The distant phosphor configuration produces more illuminating beams than the two settings containing conformal or in-cup phosphor. When this configuration is used, though, it is difficult to manage the color standard of light-emitting diodes (LEDs). As a result, in past few years, numerous studies have focused on controlling the color standard of distant phosphor configurations. Until present, two distant phosphor configurations of single- and triple-film phosphor configurations, have been used to improve color standards. This research will investigate the ideal configuration among these configurations in terms of color rendering index (CRI), color quality scale (CQS), lumen output (LO), as well as color homogeneity for multi-chip white LEDs (WLEDs). WLEDs, operating at five different temperatures of color between 5600 K and 8500 K, are used to perform the studies. The results reveal that the three-sheet phosphor setting would be more desirable, with greater CRI, CQS, and lumen efficiency (LE) indexes. Furthermore, when using a triple-layer phosphor arrangement, color variation is reduced, resulting in a rise in color consistency. This conclusion is possibly verified by using Mie theory to analyze scattering properties in distant phosphor setup, making the study findings legitimate and important data to produce more advanced WLEDs.
(Y,Gd)BO3:Eu red phosphor for dual-layer phosphor structure to enhance the op...journalBEEI
Among the structures using for fabricating white light-emitting diodes (WLEDs) such as the conformal coating or in-cup geometries, the remote phosphor structure gives the highest luminous efficacy. However, in terms of color quality, its performance is not as good as the others. The red-light compensation has been reported as the effective solution for enhancing the color quality of WLEDs. Hence, this study adopted the idea and applied to the dual-layer phosphor structure. The phosphor used to boost the red color in light formation is (Y,Gd)BO3:Eu particle. The dual-layer remote phosphor structure was simulated with the red (Y,Gd)BO3:Eu phosphor layer above the original yellow phosphor YAG:Ce3+ one. The WLEDs with different correlated color temperatures of 5600 K, 6600 K and 7700K were experimented. Mie-theory and Lambert-Beer law were applied to examine the results. The growth in color rendering index (CRI) and color quality scale (CQS) with the increase of (Y,Gd)BO3:Eu phosphor concentration was observed. Nevertheless, the lumen efficacy would be degraded if the concentration was over a certain number. The information provided in this article is useful for the development of high-power WLED production with greater color quality.
Improvement of double-layer phosphor structure WLEDS in color homogeneity and...journalBEEI
The concept of the analysis is to put a CaAl2O4:Mn2+ green phosphor layer on top of the YAG:Ce3+ yellow phosphor layer. After that, find the added CaAl2O4:Mn2+ concentration appropriate for the highest luminous flux (LF) and color homogeneity (CH). In this analysis, five equivalent WLEDs were applied but with distinct color temperatures, including 5600 K - 8500 K. The findings showed that CaAl2O4:Mn2+ brings great benefits to increase not only the luminous flux but also the color homogeneity. Especially, the higher the CaAl2O4:Mn2+ concentration, the more the luminous flux released by WLEDs, owing to the risen content of the light of green in WLEDs. Nevertheless, as the CaAl2O4:Mn2+ concentration raised significantly, a small reduction in the color rendering metric (CRI) and color quality scale (CQS) occurred. This is supported by simulation and calculation according to the theory of Monte Carlo. The paper results are the crucial contribution to the manufacture of WLEDs with better optical performance and color homogeneity of remote phosphor configurations.
The application of (Y,Gd)BO3:Tb3+ and CaGa2S4:Mn2+ phosphors to remote white ...TELKOMNIKA JOURNAL
The remote phosphor structure is superior to the conformal phosphor and the in-cup phosphor in terms of lighting efficiency; however, managing the color quality of the remote phosphor structure has been a nuisance to the manufacturers. To address this problem, many researches were conducted and the results suggested that using dual-layer phosphor structure and triple-layer phosphor structure could improve the color quality in remote phosphor structures. The purpose of this article is to study which one between the two configurations mentioned above allows multi-chip white LEDs (WLEDs) to reach highest indexes in color rendering index (CRI), color quality scale (CQS), luminous flux (LF), and color uniformity. The color temperature of the WLEDs used for the experiments in this article is 8500 K. The result of this research shows that the triple-layer phosphor configuration has higher CRI, CQS, and LE and also able to reduce color deviation resulting in better color uniformity. This conclusion can be verified by analyzing the scattering features of the phosphor layers using the Mie-theory. Being verifiable increases the reliability of the research result and makes it a valuable reference for producing better quality WLEDs.
Using phosphor ZnB2O4:Mn2+ for enhancing the illuminating beam and hue standa...TELKOMNIKA JOURNAL
The enhancement in hue uniformity and luminous production of multiple-chip white LED lamps (MCW-LEDs) using dual-layer remote phosphor packaging designs are the emphases of this paper. We blended Mn2+ activated strontium–barium silicate (ZnB2O4:Mn2+) with the phosphor mixture and manage to record significant impacts of this new phosphor mixture on the LED lights’ lighting performance. There is evidence that the growing concentration of yellow-green-emitting ZnB2O4:Mn2+ phosphor encourages the enhancement of hue uniformity and illumination effectiveness in MCW-LEDs with mean correlated hue heats (CCTs) of roughly 8500 K, though the color quality scale is gradually deteriorating. It is possible to successfully achieve such amazing MCW-LED performance if we choose the right concentration and size of ZnB2O4:Mn2+.
Research on advancing chromatic reproduction and luminosity of a WLED using t...TELKOMNIKA JOURNAL
In this study, the use of triple-sheet phosphor arrangement (TRP) in performing significant improvements to both color quality and luminous flux of white light emitting diode (WLEDs) is introduced. The phosphor layer of CaLaB3O7:Ce3+,Mn2+ is to accomplish green-spectra enhancement for the boost of luminous efficacy (LE), while MgB2O4:Mn2+ red phosphor layer is for red-spectra enhancement to better color rendering index (CRI) of WLEDs. The changes in these two phosphors’ concentrations present considerable effects on the yellow phosphor YAG:Ce3+ concentration, the color quality scale (CQS), CRI, and LE. Findings display the decrease of YAG:Ce3+ concentration accompanying the increase of red and green phosphor concentrations, for the stabilized average correlated color temperatures (ACCTs) between 6000 and 8500 K. Results also reveal that greater content of MgB2O4:Mn2+ leads to greater CRI value. Meanwhile using the increasing CaLaB3O7:Ce3+,Mn2+ concentration, the CRI lowers considerably. CQS, on the other hand, can increase with CaLaB3O7:Ce3+,Mn2+ concentration from 10% to 14%. Especially, given the enhancement for the CRI as well as CQS, LE value will surge to more than 40% due to the reduction of scattering light and the addition of green light. The outcome of the study is a priceless reference for light emitting diode (LED) producers.
The application of double-layer remote phosphor structures in increasing WLED...IJECEIAES
The remote phosphor structure often has inferior color quality but better luminous flux in than conformal or in-cup configurations. Therefore, numerous researches study remote phosphor structure for methods to enhance it chromatic quality. This study introduces the use of dual-layer remote phosphor structure in WLEDs with identical structure but at different color temperature, 6600 K and 7700 K, to demonstrate their effect on quality indicators. The concept is placing a green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb or a red phosphor layer MgSr 3 Si 2 O 8 :Eu on the layer of yellow-emitting phosphor YAG:Ce 3+ and find the suitable concentration of the additional phosphor to create the best color quality. The results showed that the increase of CRI and CQS are affected by MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ , in particular, the higher the concentration of red phosphor gets the better CRI and CQS because the emitted red light in enhanced. The green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb, on the other hand, is beneficial for the luminous flux. The concentration of MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ and (Ce,Tb)MgAl 11 O 19 :Ce:Tb, however, need to be adjusted properly to avoid decreasing the luminous flux due to overgrowth. The Mie scattering theory and Beer’s law are the verification tools for these conclusions, which gives them the credibility to be applied in producing better quality WLEDs. 2+ ,Mn 2+
SrBaSiO 4 :Eu 2+ phosphor: a novel application for improvingthe luminous flu...IJECEIAES
This paper described in detail the chromatic homogeneity and luminous flux influences in producing better quality white LED devices with various phosphor layers (MCW-LEDs). The method is to let Eu -activated strontium–barium silicate (SrBaSiO 4 :Eu 2+ ) mixed with their phosphor compounding, which results in notable impact on lighting performance. The increase in concentration of yellow-green-emitting SrBaSiO 4 :Eu phosphor also promotes the color performance and lumen output of WLED devices at high correlated color temperature around 8500K. This is the first time this approach is applied and it results can be utilized for better understanding of optical properties interaction with phosphor materials. Although SrBaSiO 4 :Eu 2+ receives many positive responses, we still need to limit it concentration for high SrBaSiO 4 :Eu 2+ concentration is detrimental to CQS. The appropriate choice of concentration and size of SrBaSiO 4 :Eu is the principal factor to decide the performance of MCW-LEDs. 2+ 2+ 2+
The options in remote phosphor structure for better white LEDs color qualityTELKOMNIKA JOURNAL
The WLEDs configuration with remote phosphor layers has higher luminescent performance than WLEDs with dispense coating or conformal coating and is applied for many modern devices. However, managing the chromatic performance of lighting structure with remote phosphor materials is a challenging objective that demands more research. This has inspired the usage of multi phosphor configurations with distance in between the layers to improve color quality. The results of this manuscript can support the manufacturers in choosing the optimal configuration for optical performance in LEDs devices with more than one phosphor material. The simulated model used in the experments is 6500 K CCT WLEDs, which results show the triple-layers structure is more favorable in terms of color quality and light output. Besides, a notable reduction occurs in color deviation means that chromatic stability is also enhanced in WLEDs with three phosphor layers. Through experimental results, which were confirmed by the Mie-scattering theory, this research offers valuable approach and details to produce better WLEDs.
(Y,Gd)BO3:Eu red phosphor for dual-layer phosphor structure to enhance the op...journalBEEI
Among the structures using for fabricating white light-emitting diodes (WLEDs) such as the conformal coating or in-cup geometries, the remote phosphor structure gives the highest luminous efficacy. However, in terms of color quality, its performance is not as good as the others. The red-light compensation has been reported as the effective solution for enhancing the color quality of WLEDs. Hence, this study adopted the idea and applied to the dual-layer phosphor structure. The phosphor used to boost the red color in light formation is (Y,Gd)BO3:Eu particle. The dual-layer remote phosphor structure was simulated with the red (Y,Gd)BO3:Eu phosphor layer above the original yellow phosphor YAG:Ce3+ one. The WLEDs with different correlated color temperatures of 5600 K, 6600 K and 7700K were experimented. Mie-theory and Lambert-Beer law were applied to examine the results. The growth in color rendering index (CRI) and color quality scale (CQS) with the increase of (Y,Gd)BO3:Eu phosphor concentration was observed. Nevertheless, the lumen efficacy would be degraded if the concentration was over a certain number. The information provided in this article is useful for the development of high-power WLED production with greater color quality.
Improvement of double-layer phosphor structure WLEDS in color homogeneity and...journalBEEI
The concept of the analysis is to put a CaAl2O4:Mn2+ green phosphor layer on top of the YAG:Ce3+ yellow phosphor layer. After that, find the added CaAl2O4:Mn2+ concentration appropriate for the highest luminous flux (LF) and color homogeneity (CH). In this analysis, five equivalent WLEDs were applied but with distinct color temperatures, including 5600 K - 8500 K. The findings showed that CaAl2O4:Mn2+ brings great benefits to increase not only the luminous flux but also the color homogeneity. Especially, the higher the CaAl2O4:Mn2+ concentration, the more the luminous flux released by WLEDs, owing to the risen content of the light of green in WLEDs. Nevertheless, as the CaAl2O4:Mn2+ concentration raised significantly, a small reduction in the color rendering metric (CRI) and color quality scale (CQS) occurred. This is supported by simulation and calculation according to the theory of Monte Carlo. The paper results are the crucial contribution to the manufacture of WLEDs with better optical performance and color homogeneity of remote phosphor configurations.
The application of (Y,Gd)BO3:Tb3+ and CaGa2S4:Mn2+ phosphors to remote white ...TELKOMNIKA JOURNAL
The remote phosphor structure is superior to the conformal phosphor and the in-cup phosphor in terms of lighting efficiency; however, managing the color quality of the remote phosphor structure has been a nuisance to the manufacturers. To address this problem, many researches were conducted and the results suggested that using dual-layer phosphor structure and triple-layer phosphor structure could improve the color quality in remote phosphor structures. The purpose of this article is to study which one between the two configurations mentioned above allows multi-chip white LEDs (WLEDs) to reach highest indexes in color rendering index (CRI), color quality scale (CQS), luminous flux (LF), and color uniformity. The color temperature of the WLEDs used for the experiments in this article is 8500 K. The result of this research shows that the triple-layer phosphor configuration has higher CRI, CQS, and LE and also able to reduce color deviation resulting in better color uniformity. This conclusion can be verified by analyzing the scattering features of the phosphor layers using the Mie-theory. Being verifiable increases the reliability of the research result and makes it a valuable reference for producing better quality WLEDs.
Using phosphor ZnB2O4:Mn2+ for enhancing the illuminating beam and hue standa...TELKOMNIKA JOURNAL
The enhancement in hue uniformity and luminous production of multiple-chip white LED lamps (MCW-LEDs) using dual-layer remote phosphor packaging designs are the emphases of this paper. We blended Mn2+ activated strontium–barium silicate (ZnB2O4:Mn2+) with the phosphor mixture and manage to record significant impacts of this new phosphor mixture on the LED lights’ lighting performance. There is evidence that the growing concentration of yellow-green-emitting ZnB2O4:Mn2+ phosphor encourages the enhancement of hue uniformity and illumination effectiveness in MCW-LEDs with mean correlated hue heats (CCTs) of roughly 8500 K, though the color quality scale is gradually deteriorating. It is possible to successfully achieve such amazing MCW-LED performance if we choose the right concentration and size of ZnB2O4:Mn2+.
Research on advancing chromatic reproduction and luminosity of a WLED using t...TELKOMNIKA JOURNAL
In this study, the use of triple-sheet phosphor arrangement (TRP) in performing significant improvements to both color quality and luminous flux of white light emitting diode (WLEDs) is introduced. The phosphor layer of CaLaB3O7:Ce3+,Mn2+ is to accomplish green-spectra enhancement for the boost of luminous efficacy (LE), while MgB2O4:Mn2+ red phosphor layer is for red-spectra enhancement to better color rendering index (CRI) of WLEDs. The changes in these two phosphors’ concentrations present considerable effects on the yellow phosphor YAG:Ce3+ concentration, the color quality scale (CQS), CRI, and LE. Findings display the decrease of YAG:Ce3+ concentration accompanying the increase of red and green phosphor concentrations, for the stabilized average correlated color temperatures (ACCTs) between 6000 and 8500 K. Results also reveal that greater content of MgB2O4:Mn2+ leads to greater CRI value. Meanwhile using the increasing CaLaB3O7:Ce3+,Mn2+ concentration, the CRI lowers considerably. CQS, on the other hand, can increase with CaLaB3O7:Ce3+,Mn2+ concentration from 10% to 14%. Especially, given the enhancement for the CRI as well as CQS, LE value will surge to more than 40% due to the reduction of scattering light and the addition of green light. The outcome of the study is a priceless reference for light emitting diode (LED) producers.
The application of double-layer remote phosphor structures in increasing WLED...IJECEIAES
The remote phosphor structure often has inferior color quality but better luminous flux in than conformal or in-cup configurations. Therefore, numerous researches study remote phosphor structure for methods to enhance it chromatic quality. This study introduces the use of dual-layer remote phosphor structure in WLEDs with identical structure but at different color temperature, 6600 K and 7700 K, to demonstrate their effect on quality indicators. The concept is placing a green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb or a red phosphor layer MgSr 3 Si 2 O 8 :Eu on the layer of yellow-emitting phosphor YAG:Ce 3+ and find the suitable concentration of the additional phosphor to create the best color quality. The results showed that the increase of CRI and CQS are affected by MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ , in particular, the higher the concentration of red phosphor gets the better CRI and CQS because the emitted red light in enhanced. The green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb, on the other hand, is beneficial for the luminous flux. The concentration of MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ and (Ce,Tb)MgAl 11 O 19 :Ce:Tb, however, need to be adjusted properly to avoid decreasing the luminous flux due to overgrowth. The Mie scattering theory and Beer’s law are the verification tools for these conclusions, which gives them the credibility to be applied in producing better quality WLEDs. 2+ ,Mn 2+
SrBaSiO 4 :Eu 2+ phosphor: a novel application for improvingthe luminous flu...IJECEIAES
This paper described in detail the chromatic homogeneity and luminous flux influences in producing better quality white LED devices with various phosphor layers (MCW-LEDs). The method is to let Eu -activated strontium–barium silicate (SrBaSiO 4 :Eu 2+ ) mixed with their phosphor compounding, which results in notable impact on lighting performance. The increase in concentration of yellow-green-emitting SrBaSiO 4 :Eu phosphor also promotes the color performance and lumen output of WLED devices at high correlated color temperature around 8500K. This is the first time this approach is applied and it results can be utilized for better understanding of optical properties interaction with phosphor materials. Although SrBaSiO 4 :Eu 2+ receives many positive responses, we still need to limit it concentration for high SrBaSiO 4 :Eu 2+ concentration is detrimental to CQS. The appropriate choice of concentration and size of SrBaSiO 4 :Eu is the principal factor to decide the performance of MCW-LEDs. 2+ 2+ 2+
The options in remote phosphor structure for better white LEDs color qualityTELKOMNIKA JOURNAL
The WLEDs configuration with remote phosphor layers has higher luminescent performance than WLEDs with dispense coating or conformal coating and is applied for many modern devices. However, managing the chromatic performance of lighting structure with remote phosphor materials is a challenging objective that demands more research. This has inspired the usage of multi phosphor configurations with distance in between the layers to improve color quality. The results of this manuscript can support the manufacturers in choosing the optimal configuration for optical performance in LEDs devices with more than one phosphor material. The simulated model used in the experments is 6500 K CCT WLEDs, which results show the triple-layers structure is more favorable in terms of color quality and light output. Besides, a notable reduction occurs in color deviation means that chromatic stability is also enhanced in WLEDs with three phosphor layers. Through experimental results, which were confirmed by the Mie-scattering theory, this research offers valuable approach and details to produce better WLEDs.
The improvement of the color rendering index using convex-dual-layer remote p...TELKOMNIKA JOURNAL
White-light emitting diodes (WLEDs) are semiconductor light sources whose construction design is usually made up of a single pumping chip and a single light-conversion film of phosphor compound. The outstanding problem of this traditional setting is the inadequate chroma rendering index (CRI). Introducing a cluster of multiple blue chips with more than one phosphor layer is demonstrated to address that flaw of W-LEDs. This package is called the dual-film remote-phosphor multi-chip WLED. As a consequence, both the light brightness and the CRI are improved. However, for the maximum results, the test on the second layer of phosphor has been performed to continually alter the proportions and densities of phosphor within the silicone. The researchers employed a unique hue design to control the white-light light emitting diode (LED) module. When comparing the actual result to the simulated color coordinates under the hue standard of international commission on illumination (CIE) 1931, the highest difference is found to be around 0.0063 for correlated color temperatures (CCT) of 6600 K and 7700 K. Experiments indicate that the setting of multi-chip and dual-phosphorus is the optimal design for supporting CRI quality and luminous intensity.
Application of dual-layer phosphor geometries for enhancing the optical prope...TELKOMNIKA JOURNAL
This article compares the lumen output of two packages of two-remote phosphor (RP). The first package is flat dual-remote phosphor (FDRPS). The second package is concave dual-remote phosphor (CDRP). The dispersion qualities of the white-light-emitting diode are different as a result of their different cover designs, leading to a disparity between the FDRPS and CDRPS configurations. The results of the study show that the FDRPS package yields a lumen output superior to that of the CDRPS package. In the article, we can also see how the space among the phosphor films (𝑑1) and the space among the phosphor film and the light emitting diodes (LED) outer side (𝑑2) might affect the light characteristics in the CDRPS model. As the indicated distances shift, the characteristics of dispersion and absorptivity in the distant phosphor film will shift as well. Such an occurrence can have an impact on chromatic uniformity as well as optical performance in white light emitting diodes (WLEDs). If we modify the and values, it is necessary to change the phosphor YAG:Ce3+ concentration in the WLEDs to keep the correlated color temperature at 8500 K.
Dual-layer remote phosphor structure: a novel technique to enhance the color ...IJECEIAES
The effects of red light-emitting phosphor CaMgSi2O6:Eu2+,Mn2+ on the optical properties of single-layer remote phosphor structure (SRPS) and dual-layer remote phosphor structure (DRPS) are the focus of this study. The differences in color quality and luminous flux (LF) of white lightemitting diodes (WLEDs) between these two structures are also revealed and demonstrated based on the Mie theory. SRPS consists of one mixed phosphor layer betweenCaMgSi2O6:Eu2+,Mn2+ andYAG:Ce3+particles, while DRPS includes two separated layers: red phosphor layer and yellow phosphor layer. In this work, 5% SiO2 is added into the phosphor layers to increase scattering abilities. Discrepancies in structures greatly affect the optical characteristics of WLEDs. The results showed that the color rendering index (CRI) increased with the concentration in both structures with nearly equal values. Meanwhile, color quality scale (CQS) of DPRS is 74 at ACCTs ranging from 5600K to 8500K, higher than CQS of SRPS which is only 71 at 8500K. In addition, the luminous flux of DRPS is significantly higher than SRPS at 2% -14% of CaMgSi2O6:Eu2+,Mn2+. In summary, DRPS is better for color quality and lumen outputin comparison to SRPS and adding the right amount of red phosphor can enhance CQS and LF.
emote phosphor constructions usually have color quality drawbacks but are more luminous in terms of lumen, surpassing conformal phosphor or in-cup layouts of phosphor. From this disadvantage, there is a great number of studies carried out to boost the chromatic performance in remote phosphor (RP) structures. This work focuses on using a two-layer RP or dual-film RP (DFRP) to improve the color rendering indices (CRI) as well as color quality scales (CQS) for white light emitting diodes (WLEDs). Two equivalent dual remote phosphor (DRP) structures for WLEDs operating at various temperatures of color including 5600 K, 7000 K, as well as 8500 K will be employed for our study. The study’s idea involves putting one phosphor Zn2SiO4:Mn2+,P layer or one red phosphor Mg2SiO4:Mn2+ layer on top of the yellow YAG:Ce3+. Subsequently modifying the concentration for each red and green phosphor to investigate the changes in color metrics and luminous flux. As a result, a suitable red and green phosphor concentration can be determined to acquire desired outcomes for each DFRP-WLED. Obtained results show that Mg2SiO4:Mn2+ performs significant boosting on both CRI and CQS, especially when being integrated with increasing concentration, thanks to the increased red-light presence for the WLED device. In addition, the sheet of phosphor Zn2SiO4:Mn2+,P benefits the luminous flux.
The influences of calcium fluoride and silica particles on improving color ho...TELKOMNIKA JOURNAL
The LEDs lighting device with phosphor ingredient (pcLEDs) is among the most common lighting methods in recent years and evaluated by chromatic uniformity and lighting capacity. Therefore, we introduce the phosphor particles that can improve the scattering efficiency (SEPs) to apply in pcLEDs at 8500 K correlated color temperature (CCT) with the expectation to produce better pcLEDs by enhancing both quantity and quality of emitted light. Combining various materials such as CaF2 and SiO2 with yellow Y3Al5O12:Ce3+ phosphor composition in the pcLEDs simulation created by the LightTools program is the mechanism of this research. The simulated pcLEDs are tested and the results will be verified with Mie-scattering theory. The observation of the simulation leads to the conclusion about the scattering coefficients of SEPs at 455 nm and 595 nm wavelengths. The calculation showed that CaF2 is better for color homogeneity yet suffer from luminous flux deficiency as the concentration gets higher. On the other hand, SiO2 is the scattering enhancement material that can maintain high luminous flux regardless of its concentration.
Study of red-emitting LaAsO4:Eu3+ phosphor for color rendering index improvem...TELKOMNIKA JOURNAL
The remote phosphor structure is often disadvantageous in color quality but in terms of optics it is more convenient when compared to other phosphor structures such as conformal or in-cup ones. From this disadvantage, there are many studies to improve its chromatic output. In this research paper, we propose a dual-layer remote phosphor geometry for the improvement of white light-emitting diodes (WLEDs) in two parameters: color rendering index (CRI) and color quality scale (CQS). The 7700 K WLEDs are used in this study. The idea of the study is to place a red phosphor layer LaAsO4:Eu3+ on the yellow phosphor YAG: Ce3+, and then find the concentration of LaAsO4:Eu3+ in an appropriate way to achieve the highest color quality. The results showed that LaAsO4:Eu3+ bring great benefits for enhancing CRI and CQS. In particular, the greater the concentration of LaAsO4:Eu3+, the greater the CRI and CQS because the portion of red lights in WLEDs increases. However, the decrease in lumen output occurs when the concentration of LaAsO4:Eu3+ increases excessively. This is proved thanks to Mie-scattering theory and Beer-Lambert law. The results of important articles in WLEDs fabrication have greatly contributed to a higher white light quality.
Using triple-layer remote phosphor structures LaVO4:Eu3+ and ZnS:Cu,Sn to imp...TELKOMNIKA JOURNAL
This research paper investigates the novel triple remote phosphor layer for improving the remote phosphor’s angular chroma uniformity (ACU) of down-light lamps by using remote micro-patterned phosphor layers (RMPP). In addition, introducing the triple-layer (TL) RMPP is introduced to offer the potential approach to this objective. This analysis also measures the optical efficiency of the layers and the angle distribution of angular correlated color temperature (ACCT). Drawing a comparison between the traditional
dual-layer (DL) RMPP and the proposed TL is furthermore critical to this study. According to the findings, the triple-layer phosphor configuration can achieve greater hue consistency while having a correlating colour temperature (CCT) variance merely measured at 441 K. Results in the single RMPP layer are 1390 K of the remote phosphor (RP) sheet setting and
556 K for the ACCT deviation. The recreation employing finite-difference
time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in angular color uniformity (ACU). The structure of DL and TL RMPPs results in a 6.68 % and 4.69 % gain in luminous efficiency, respectively, with the standard RMPP layer at a currently driving of 350 mA. The micro-patterned layer’s scattering characteristic and mixing effect may account for the increased ACU and luminous efficiency.
The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote ...TELKOMNIKA JOURNAL
Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs.
Benefits of triple-layer remote phosphor structure in improving color quality...TELKOMNIKA JOURNAL
This document discusses the benefits of using a triple-layer remote phosphor structure to improve the color quality and luminous flux of white LEDs. It compares single-layer, dual-layer, and triple-layer phosphor configurations. The results show that the triple-layer structure is most effective at improving the color rendering index, color quality scale, and luminous efficacy. By separating the phosphor layers into yellow, red, and green, the triple-layer structure better balances the complementary colors and reduces light re-absorption losses compared to other structures. The enhanced optical performance of the triple-layer structure can be explained by Mie scattering theory and how it applies to the phosphor particle distributions in each layer. Overall,
Chroma consistency and luminous efficacy for a WLED using remote phosphor con...TELKOMNIKA JOURNAL
The light quality of white-light-emitting diodes (WLEDs), an essential element for the improvement of WLEDs performance, can now be estimated by the angular color uniformity (ACU). In this study, a single
micro-patterned layer is used to compare the variations between the traditional remote phosphor (RP) layer and the remote phosphor layer (single remote micro-patterned phosphor film (RMPP) layer). Furthermore,
we investigate the application of a novel triple remote phosphor layer to improve the ACU in RP down-light lamps. Besides, the optical efficiency of the layers as well as the distribution for the angular correlated color temperature (ACCT) were also measured experimentally. According to the findings, the dual-RMPP-layer structure can achieve better chromatic uniformity with just 441 K of correlated color temperature (CCT) variance. Meanwhile, the single RMPP layer shows an ACCT deviation of 556 K and RP film structure of 1390 K. The simulation incorporating e finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in ACU. Furthermore, compare to the traditional RP layer,
the single and dual RMPP layers configuration result in respective luminous efficiency ameliorations of 6.68% and 4.69%. The scattering principle and combining influence from the micro-molded layer may explain the enhancement in ACU as well as lumen.
Improving luminous flux and color homogeneity of dual-layer phosphor sctructureTELKOMNIKA JOURNAL
In order to clarify the main purpose of the study, we put a green phosphor layer SrBaSiO4:Eu2+
on the yellow phosphorus layer YAG:Ce3+ through using only one WLEDs structure in different color
temperatures like 5600 K, 6600 K, 7700 K. Then, we find the suitable SrBaSiO4:Eu2+ concentration in order
that the luminous flux could get the highest value. The results show that SrBaSiO4:Eu2+ brings great
benefits to increase not only optical gain but also color uniformity. Specifically, the greater
the SrBaSiO4:Eu2+ concentration, the greater the output of WLEDs because of the development of green
light component in WLEDs. However, only if the SrBaSiO4:Eu2+ concentration exceeds the level, a slight
decrease in color rendering index (CRI) can occur, which based on Monte Carlo simulation. In addition,
the results of this paper have contributed significantly to the creation of higher-powered WLEDs.
Improving the optical efficiency of white light-emitting diodes based on phos...journalBEEI
While the remote phosphor structure is not an appropriate solution for WLED color uniformity, it is more advantageous for the luminous output of WLED than the conformal phosphor or in-cup phosphor structure. Acknowledging the ability of the remote phosphor structure, many studies have been carried out to surmount the color quality disadvantage of this structure. A dual-layer remote phosphor configuration is proposed in this research paper to acquire better color quality for WLEDs through heightening the color rendering index (CRI) and the color quality scale (CQS). The color temperature of the WLED packages this study is 8500 K. By inserting a layer of green CaSO4:Ce3+,Mn2+ or red LiLaO2:Eu3+ phosphor on the yellow YAG:Ce3+ phosphor layer, the phosphor structure configuration can be constructed. Then, to get the best color quality, the concentration of added phosphor LiLaO2:Eu3+ would be changed. The findings showed the rise of CRI and CQS along with the LiLaO2:Eu3+, which implies the influence of LiLaO2:Eu3+ to the growth of red light components within WLEDs packages. The greater the concentration of LiLaO2:Eu3+ is, the more the CRI and CQS increase. Meanwhile, the luminous flux gains from the green phosphor CaSO4:Ce3+,Mn2+. Nevertheless, the luminous flux and color quality would decrease if the concentrations of both red LiLaO2:Eu3+ and green CaSO4:Ce3+,Mn2+ phosphors reach a certain corresponding level. Centered on the Mie-scattering theory and the law of Lambert-Beer, this result is illustrated. The findings in this research are vital references for manufacturing WLEDs with higher white light performance.
The application of green YF3:Er3+,Yb3+ and red MgSr3Si2O8:Eu2+,Mn2+ layers to...TELKOMNIKA JOURNAL
White light-emitting diodes (WLEDs) with quantum dots (QDs) and phosphor have pulled in huge consideration because of their incredible shading rendering capacity. In the bundling procedure, a QDs film and a phosphor silicone layer will in general be isolated for lessening the reabsorption misfortunes and keeping the QDs surface molecules in a good condition. This examination explored the bundling succession of QDs and phosphor layers to the optical and warm exhibitions of WLEDs. The emitted optical power and PL spectra were estimated and dissected, while an infrared warm imager was utilized to reenact and approve tentatively the temperature fields. The results reveal that at 60 mA, WLEDs with green QDs-on-phosphor type accomplished lumen output (LO) of 1578 lm, with shading rendering record (CRI) of Ra = 60, while the red QDs-on-phosphor type WLEDs exhibited lower LO of 1000 lm, with Ra = 82. In addition, the QDs-onphosphor type WLEDs generated less warmth than the other, and as a result, the most noteworthy temperature in this packaged type was lower than the other. Additionally, its temperature contrast can arrive at 12.3°C. Along these lines, regarding bundling arrangement, the QDs-on-phosphor type is an ideal bundling design to better the optical productivity and shading rendering capacity, as well as lower gadget temperature.
Enhancing the CRI and lumen output for the 6600 K WLED with convex-dual-layer...IJECEIAES
The traditional white LED product established with a single chip and a single phosphor results in a low color rendering index (CRI). The upgrade of LED package is comprised of two chips and one phosphor material and gives the higher CRI while keeping high luminous efficiency. Based on previous findings, the research paper performs the application of the two chips and two phosphors to enhance the color tunability of LEDs with different amounts and intensities of the two employed phosphors. Additionally, a color design model is built to serve the purpose of bettering the color fine-tuning of the white-light LED module. The maximum value of the difference between the measured CIE 1931 color coordinates and that of the simulated model is approximately 0.0063 around the 6600 K correlated color temperature (CCT). From the results, this study offers a quick approach to achieve the color fine tuning of a white-light LED module with a high CRI and luminous efficiency.
For improvements in chromatic scales and luminescent fluxes of white lights: ...TELKOMNIKA JOURNAL
This study compares red-phosphor LaOF:Eu3+ impacts on a single-film remote phosphor configuration (SRPC) and a double-film remote phosphor configuration (DRPC). Mie theory is used to demonstrate the relationship between light flux and color quality. SRPC is a phosphor layer consisting of LaOF:Eu3+ particles mixed with YAG:Ce3+. Meanwhile, DRPC is two separate films of red and yellow phosphors. To increase scattering properties, we added 5% SiO2 into phosphor layers. The differences in structure affect significantly white light emitting diodes’ (WLEDs’) optical properties. Attained figures and statistics show that the color rendering indices (CRIs) increase along with the concentrations of both structures, and these numbers are approximately similar. However, DPRC exhibits a color quality scale (CQS) of 74 in all examined chromatic temperatures (5600 K - 8500 K), which is greater than SRPC’s 71 at 8500 K. Besides, the luminous efficiencies (LEs) in DRPC are more outstanding than that of SRPC, at given LaOF:Eu3+ concentration percentages (2%-14%). To summarize, DRPC offers greater benefits in luminous flux and color quality, compared to SRPC. Choosing the proper red light phosphor concentration, on the other hand, becomes a crucial aspect of achieving the ideal CQS and LEs.
Utilizing CaCO 3 , CaF 2 , SiO 2 , and TiO 2 particles to enhance color hom...IJECEIAES
The chromatic homogeneity and luminous efficiency are two crucial elements for determining a high-quality phosphor-converted LEDs (pc-LEDs). Thus, this paper provides essential information in choosing the particles to enhance lighting properties of high performance pc-LEDs. Scattering enhancement particles (SEP) such as CaCO 3 , CaF 2 , SiO 2 , and TiO 2 , are combined with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ and applied to the lighting devices. Initially, optical simulations are carried out with the support of LightTools program. Next, the Mie-theory is applied to calculate and confirm the results. The calculation subjects are SEPs scattering properties within the band 455 -595 nm. The scattering results of TiO 2 suggest it is the optimal choice for pc-LEDs color quality in comparison to the other SEPs; however, it causes the luminous flux to decrease significantly along with the increase in its concentration. Besides, with the addition of SiO 2 grains, we can accomplish higher lumen output at all particle sizes. Meanwhile, the application of 30% CaCO 3 can decreas the CCT deviation by 620 K making CaCO 3 the potential particle to be selected for chromatic quality and light output enhancement of pc-LEDs.
Excellent color quality of phosphor converted white light emitting diodes wit...TELKOMNIKA JOURNAL
The remote phosphor structure is disadvantageous in color quality but more convenient in luminous flux when compared to conformal phosphor or in-cup phosphor structure. From this disadvantage, there are many studies to improve the color quality of the remote phosphor structure. This research will propose a dual-layer remote phosphor structure to improve color rendering index (CRI) and color quality scale (CQS) of WLEDs. The WLED package with color temperature of 8500 K is utilized in this study. The idea of the study is to locate a layer of phosphor green Y2O2S:Tb3+ or red ZnS:Sn2+ on the yellow phosphor YAG:Ce3+ film, and then finding the suitable added concentration of ZnS:Sn2+ to match the highest color quality. The results showed that ZnS:Sn2+ brings great benefits to increase CRI and CQS. The greater the ZnS:Sn2+ concentration is, the higher the CRI and CQS become owing to the rise in red light components in WLEDs. Meanwhile, the green Y2O2S:Tb3+ phosphor brings benefits to luminous flux. However, the decrease in luminous flux and color quality occurs when the concentration of ZnS:Sn2+ and Y2O2S:Tb3+ exceeds the corresponding level. This is proved by applying Mie-scattering theory and Lambert-Beer's law. The results of articles are important for WLEDs’ fabrication having higher white light quality.
Using SiO 2 nano-particles for better color uniformity and lumen output in 8...IJECEIAES
In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO 2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO 2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO 2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO 2 -doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO 2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO 2 -doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO 2 . These experimental outcomes suggest that SiO 2 is an effective material to add in WLEDs structure for better lighting efficiency.
Influence of Dual-layer and Triple-layer Remote Phosphor Package on Optical P...TELKOMNIKA JOURNAL
In this paper, the influence of the distance between phosphor layers in the dual-layer and triple- layer remote package on luminous flux and color rendering property is presented and analyzed. During the simulation, it is recognized that an appropriate distance can produce higher quality of the multi-chip white LED (MCW-LEDs) through adjusting the distance between two and three phosphor layers. According to the research results, 0.1mm is the outstanding distance between two phosphor layers so that the performance of MCW-LEDs can be accomplished the best optimal effect. In addition, the simulation results show that the dual-layer structure yielded higher optical properties than the triple-layer structure in relation to the distance. The highest lumen output of triple layer-structure can be achieved at the distance of 0.6 mm and dual-layer structure is 0.1 mm. Meanwhile, the color rendering index (CRI) changes insignificantly when the distance increases. Triple layer package is not practical for high power white LEDs due to high cost and low conversion efficiency. Dual-layer remote phosphor package with the distance between two phosphor layers of 0.1mm is an optimal structure of LEDs in improving the luminous efficiency and the color quality.
Na3Ce(PO4)2:Tb3+ and Na(Mg2–xMnX)LiSi4O10F2:Mn phosphors: a suitable selectio...TELKOMNIKA JOURNAL
This document discusses a triple-layer remote phosphor structure (TRP) to enhance the color quality and luminous flux of white light-emitting diodes (WLEDs). The TRP structure contains three phosphor layers arranged from bottom to top: yellow YAG:Ce3+ phosphor, green Na3Ce(PO4)2:Tb3+ phosphor, and red Na(Mg2–xMnX)LiSi4O10F2:Mn phosphor. Simulation results show that the red phosphor improves color rendering index while the green phosphor improves luminous flux but reduces color rendering index. The color quality scale is maximized when there is a balance between the yellow,
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
More Related Content
Similar to The better distant phosphor configurations for enhancing WLED color intensity: YVO4:Eu3+ and YF3:Mn2+
The improvement of the color rendering index using convex-dual-layer remote p...TELKOMNIKA JOURNAL
White-light emitting diodes (WLEDs) are semiconductor light sources whose construction design is usually made up of a single pumping chip and a single light-conversion film of phosphor compound. The outstanding problem of this traditional setting is the inadequate chroma rendering index (CRI). Introducing a cluster of multiple blue chips with more than one phosphor layer is demonstrated to address that flaw of W-LEDs. This package is called the dual-film remote-phosphor multi-chip WLED. As a consequence, both the light brightness and the CRI are improved. However, for the maximum results, the test on the second layer of phosphor has been performed to continually alter the proportions and densities of phosphor within the silicone. The researchers employed a unique hue design to control the white-light light emitting diode (LED) module. When comparing the actual result to the simulated color coordinates under the hue standard of international commission on illumination (CIE) 1931, the highest difference is found to be around 0.0063 for correlated color temperatures (CCT) of 6600 K and 7700 K. Experiments indicate that the setting of multi-chip and dual-phosphorus is the optimal design for supporting CRI quality and luminous intensity.
Application of dual-layer phosphor geometries for enhancing the optical prope...TELKOMNIKA JOURNAL
This article compares the lumen output of two packages of two-remote phosphor (RP). The first package is flat dual-remote phosphor (FDRPS). The second package is concave dual-remote phosphor (CDRP). The dispersion qualities of the white-light-emitting diode are different as a result of their different cover designs, leading to a disparity between the FDRPS and CDRPS configurations. The results of the study show that the FDRPS package yields a lumen output superior to that of the CDRPS package. In the article, we can also see how the space among the phosphor films (𝑑1) and the space among the phosphor film and the light emitting diodes (LED) outer side (𝑑2) might affect the light characteristics in the CDRPS model. As the indicated distances shift, the characteristics of dispersion and absorptivity in the distant phosphor film will shift as well. Such an occurrence can have an impact on chromatic uniformity as well as optical performance in white light emitting diodes (WLEDs). If we modify the and values, it is necessary to change the phosphor YAG:Ce3+ concentration in the WLEDs to keep the correlated color temperature at 8500 K.
Dual-layer remote phosphor structure: a novel technique to enhance the color ...IJECEIAES
The effects of red light-emitting phosphor CaMgSi2O6:Eu2+,Mn2+ on the optical properties of single-layer remote phosphor structure (SRPS) and dual-layer remote phosphor structure (DRPS) are the focus of this study. The differences in color quality and luminous flux (LF) of white lightemitting diodes (WLEDs) between these two structures are also revealed and demonstrated based on the Mie theory. SRPS consists of one mixed phosphor layer betweenCaMgSi2O6:Eu2+,Mn2+ andYAG:Ce3+particles, while DRPS includes two separated layers: red phosphor layer and yellow phosphor layer. In this work, 5% SiO2 is added into the phosphor layers to increase scattering abilities. Discrepancies in structures greatly affect the optical characteristics of WLEDs. The results showed that the color rendering index (CRI) increased with the concentration in both structures with nearly equal values. Meanwhile, color quality scale (CQS) of DPRS is 74 at ACCTs ranging from 5600K to 8500K, higher than CQS of SRPS which is only 71 at 8500K. In addition, the luminous flux of DRPS is significantly higher than SRPS at 2% -14% of CaMgSi2O6:Eu2+,Mn2+. In summary, DRPS is better for color quality and lumen outputin comparison to SRPS and adding the right amount of red phosphor can enhance CQS and LF.
emote phosphor constructions usually have color quality drawbacks but are more luminous in terms of lumen, surpassing conformal phosphor or in-cup layouts of phosphor. From this disadvantage, there is a great number of studies carried out to boost the chromatic performance in remote phosphor (RP) structures. This work focuses on using a two-layer RP or dual-film RP (DFRP) to improve the color rendering indices (CRI) as well as color quality scales (CQS) for white light emitting diodes (WLEDs). Two equivalent dual remote phosphor (DRP) structures for WLEDs operating at various temperatures of color including 5600 K, 7000 K, as well as 8500 K will be employed for our study. The study’s idea involves putting one phosphor Zn2SiO4:Mn2+,P layer or one red phosphor Mg2SiO4:Mn2+ layer on top of the yellow YAG:Ce3+. Subsequently modifying the concentration for each red and green phosphor to investigate the changes in color metrics and luminous flux. As a result, a suitable red and green phosphor concentration can be determined to acquire desired outcomes for each DFRP-WLED. Obtained results show that Mg2SiO4:Mn2+ performs significant boosting on both CRI and CQS, especially when being integrated with increasing concentration, thanks to the increased red-light presence for the WLED device. In addition, the sheet of phosphor Zn2SiO4:Mn2+,P benefits the luminous flux.
The influences of calcium fluoride and silica particles on improving color ho...TELKOMNIKA JOURNAL
The LEDs lighting device with phosphor ingredient (pcLEDs) is among the most common lighting methods in recent years and evaluated by chromatic uniformity and lighting capacity. Therefore, we introduce the phosphor particles that can improve the scattering efficiency (SEPs) to apply in pcLEDs at 8500 K correlated color temperature (CCT) with the expectation to produce better pcLEDs by enhancing both quantity and quality of emitted light. Combining various materials such as CaF2 and SiO2 with yellow Y3Al5O12:Ce3+ phosphor composition in the pcLEDs simulation created by the LightTools program is the mechanism of this research. The simulated pcLEDs are tested and the results will be verified with Mie-scattering theory. The observation of the simulation leads to the conclusion about the scattering coefficients of SEPs at 455 nm and 595 nm wavelengths. The calculation showed that CaF2 is better for color homogeneity yet suffer from luminous flux deficiency as the concentration gets higher. On the other hand, SiO2 is the scattering enhancement material that can maintain high luminous flux regardless of its concentration.
Study of red-emitting LaAsO4:Eu3+ phosphor for color rendering index improvem...TELKOMNIKA JOURNAL
The remote phosphor structure is often disadvantageous in color quality but in terms of optics it is more convenient when compared to other phosphor structures such as conformal or in-cup ones. From this disadvantage, there are many studies to improve its chromatic output. In this research paper, we propose a dual-layer remote phosphor geometry for the improvement of white light-emitting diodes (WLEDs) in two parameters: color rendering index (CRI) and color quality scale (CQS). The 7700 K WLEDs are used in this study. The idea of the study is to place a red phosphor layer LaAsO4:Eu3+ on the yellow phosphor YAG: Ce3+, and then find the concentration of LaAsO4:Eu3+ in an appropriate way to achieve the highest color quality. The results showed that LaAsO4:Eu3+ bring great benefits for enhancing CRI and CQS. In particular, the greater the concentration of LaAsO4:Eu3+, the greater the CRI and CQS because the portion of red lights in WLEDs increases. However, the decrease in lumen output occurs when the concentration of LaAsO4:Eu3+ increases excessively. This is proved thanks to Mie-scattering theory and Beer-Lambert law. The results of important articles in WLEDs fabrication have greatly contributed to a higher white light quality.
Using triple-layer remote phosphor structures LaVO4:Eu3+ and ZnS:Cu,Sn to imp...TELKOMNIKA JOURNAL
This research paper investigates the novel triple remote phosphor layer for improving the remote phosphor’s angular chroma uniformity (ACU) of down-light lamps by using remote micro-patterned phosphor layers (RMPP). In addition, introducing the triple-layer (TL) RMPP is introduced to offer the potential approach to this objective. This analysis also measures the optical efficiency of the layers and the angle distribution of angular correlated color temperature (ACCT). Drawing a comparison between the traditional
dual-layer (DL) RMPP and the proposed TL is furthermore critical to this study. According to the findings, the triple-layer phosphor configuration can achieve greater hue consistency while having a correlating colour temperature (CCT) variance merely measured at 441 K. Results in the single RMPP layer are 1390 K of the remote phosphor (RP) sheet setting and
556 K for the ACCT deviation. The recreation employing finite-difference
time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in angular color uniformity (ACU). The structure of DL and TL RMPPs results in a 6.68 % and 4.69 % gain in luminous efficiency, respectively, with the standard RMPP layer at a currently driving of 350 mA. The micro-patterned layer’s scattering characteristic and mixing effect may account for the increased ACU and luminous efficiency.
The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote ...TELKOMNIKA JOURNAL
Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs.
Benefits of triple-layer remote phosphor structure in improving color quality...TELKOMNIKA JOURNAL
This document discusses the benefits of using a triple-layer remote phosphor structure to improve the color quality and luminous flux of white LEDs. It compares single-layer, dual-layer, and triple-layer phosphor configurations. The results show that the triple-layer structure is most effective at improving the color rendering index, color quality scale, and luminous efficacy. By separating the phosphor layers into yellow, red, and green, the triple-layer structure better balances the complementary colors and reduces light re-absorption losses compared to other structures. The enhanced optical performance of the triple-layer structure can be explained by Mie scattering theory and how it applies to the phosphor particle distributions in each layer. Overall,
Chroma consistency and luminous efficacy for a WLED using remote phosphor con...TELKOMNIKA JOURNAL
The light quality of white-light-emitting diodes (WLEDs), an essential element for the improvement of WLEDs performance, can now be estimated by the angular color uniformity (ACU). In this study, a single
micro-patterned layer is used to compare the variations between the traditional remote phosphor (RP) layer and the remote phosphor layer (single remote micro-patterned phosphor film (RMPP) layer). Furthermore,
we investigate the application of a novel triple remote phosphor layer to improve the ACU in RP down-light lamps. Besides, the optical efficiency of the layers as well as the distribution for the angular correlated color temperature (ACCT) were also measured experimentally. According to the findings, the dual-RMPP-layer structure can achieve better chromatic uniformity with just 441 K of correlated color temperature (CCT) variance. Meanwhile, the single RMPP layer shows an ACCT deviation of 556 K and RP film structure of 1390 K. The simulation incorporating e finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in ACU. Furthermore, compare to the traditional RP layer,
the single and dual RMPP layers configuration result in respective luminous efficiency ameliorations of 6.68% and 4.69%. The scattering principle and combining influence from the micro-molded layer may explain the enhancement in ACU as well as lumen.
Improving luminous flux and color homogeneity of dual-layer phosphor sctructureTELKOMNIKA JOURNAL
In order to clarify the main purpose of the study, we put a green phosphor layer SrBaSiO4:Eu2+
on the yellow phosphorus layer YAG:Ce3+ through using only one WLEDs structure in different color
temperatures like 5600 K, 6600 K, 7700 K. Then, we find the suitable SrBaSiO4:Eu2+ concentration in order
that the luminous flux could get the highest value. The results show that SrBaSiO4:Eu2+ brings great
benefits to increase not only optical gain but also color uniformity. Specifically, the greater
the SrBaSiO4:Eu2+ concentration, the greater the output of WLEDs because of the development of green
light component in WLEDs. However, only if the SrBaSiO4:Eu2+ concentration exceeds the level, a slight
decrease in color rendering index (CRI) can occur, which based on Monte Carlo simulation. In addition,
the results of this paper have contributed significantly to the creation of higher-powered WLEDs.
Improving the optical efficiency of white light-emitting diodes based on phos...journalBEEI
While the remote phosphor structure is not an appropriate solution for WLED color uniformity, it is more advantageous for the luminous output of WLED than the conformal phosphor or in-cup phosphor structure. Acknowledging the ability of the remote phosphor structure, many studies have been carried out to surmount the color quality disadvantage of this structure. A dual-layer remote phosphor configuration is proposed in this research paper to acquire better color quality for WLEDs through heightening the color rendering index (CRI) and the color quality scale (CQS). The color temperature of the WLED packages this study is 8500 K. By inserting a layer of green CaSO4:Ce3+,Mn2+ or red LiLaO2:Eu3+ phosphor on the yellow YAG:Ce3+ phosphor layer, the phosphor structure configuration can be constructed. Then, to get the best color quality, the concentration of added phosphor LiLaO2:Eu3+ would be changed. The findings showed the rise of CRI and CQS along with the LiLaO2:Eu3+, which implies the influence of LiLaO2:Eu3+ to the growth of red light components within WLEDs packages. The greater the concentration of LiLaO2:Eu3+ is, the more the CRI and CQS increase. Meanwhile, the luminous flux gains from the green phosphor CaSO4:Ce3+,Mn2+. Nevertheless, the luminous flux and color quality would decrease if the concentrations of both red LiLaO2:Eu3+ and green CaSO4:Ce3+,Mn2+ phosphors reach a certain corresponding level. Centered on the Mie-scattering theory and the law of Lambert-Beer, this result is illustrated. The findings in this research are vital references for manufacturing WLEDs with higher white light performance.
The application of green YF3:Er3+,Yb3+ and red MgSr3Si2O8:Eu2+,Mn2+ layers to...TELKOMNIKA JOURNAL
White light-emitting diodes (WLEDs) with quantum dots (QDs) and phosphor have pulled in huge consideration because of their incredible shading rendering capacity. In the bundling procedure, a QDs film and a phosphor silicone layer will in general be isolated for lessening the reabsorption misfortunes and keeping the QDs surface molecules in a good condition. This examination explored the bundling succession of QDs and phosphor layers to the optical and warm exhibitions of WLEDs. The emitted optical power and PL spectra were estimated and dissected, while an infrared warm imager was utilized to reenact and approve tentatively the temperature fields. The results reveal that at 60 mA, WLEDs with green QDs-on-phosphor type accomplished lumen output (LO) of 1578 lm, with shading rendering record (CRI) of Ra = 60, while the red QDs-on-phosphor type WLEDs exhibited lower LO of 1000 lm, with Ra = 82. In addition, the QDs-onphosphor type WLEDs generated less warmth than the other, and as a result, the most noteworthy temperature in this packaged type was lower than the other. Additionally, its temperature contrast can arrive at 12.3°C. Along these lines, regarding bundling arrangement, the QDs-on-phosphor type is an ideal bundling design to better the optical productivity and shading rendering capacity, as well as lower gadget temperature.
Enhancing the CRI and lumen output for the 6600 K WLED with convex-dual-layer...IJECEIAES
The traditional white LED product established with a single chip and a single phosphor results in a low color rendering index (CRI). The upgrade of LED package is comprised of two chips and one phosphor material and gives the higher CRI while keeping high luminous efficiency. Based on previous findings, the research paper performs the application of the two chips and two phosphors to enhance the color tunability of LEDs with different amounts and intensities of the two employed phosphors. Additionally, a color design model is built to serve the purpose of bettering the color fine-tuning of the white-light LED module. The maximum value of the difference between the measured CIE 1931 color coordinates and that of the simulated model is approximately 0.0063 around the 6600 K correlated color temperature (CCT). From the results, this study offers a quick approach to achieve the color fine tuning of a white-light LED module with a high CRI and luminous efficiency.
For improvements in chromatic scales and luminescent fluxes of white lights: ...TELKOMNIKA JOURNAL
This study compares red-phosphor LaOF:Eu3+ impacts on a single-film remote phosphor configuration (SRPC) and a double-film remote phosphor configuration (DRPC). Mie theory is used to demonstrate the relationship between light flux and color quality. SRPC is a phosphor layer consisting of LaOF:Eu3+ particles mixed with YAG:Ce3+. Meanwhile, DRPC is two separate films of red and yellow phosphors. To increase scattering properties, we added 5% SiO2 into phosphor layers. The differences in structure affect significantly white light emitting diodes’ (WLEDs’) optical properties. Attained figures and statistics show that the color rendering indices (CRIs) increase along with the concentrations of both structures, and these numbers are approximately similar. However, DPRC exhibits a color quality scale (CQS) of 74 in all examined chromatic temperatures (5600 K - 8500 K), which is greater than SRPC’s 71 at 8500 K. Besides, the luminous efficiencies (LEs) in DRPC are more outstanding than that of SRPC, at given LaOF:Eu3+ concentration percentages (2%-14%). To summarize, DRPC offers greater benefits in luminous flux and color quality, compared to SRPC. Choosing the proper red light phosphor concentration, on the other hand, becomes a crucial aspect of achieving the ideal CQS and LEs.
Utilizing CaCO 3 , CaF 2 , SiO 2 , and TiO 2 particles to enhance color hom...IJECEIAES
The chromatic homogeneity and luminous efficiency are two crucial elements for determining a high-quality phosphor-converted LEDs (pc-LEDs). Thus, this paper provides essential information in choosing the particles to enhance lighting properties of high performance pc-LEDs. Scattering enhancement particles (SEP) such as CaCO 3 , CaF 2 , SiO 2 , and TiO 2 , are combined with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ and applied to the lighting devices. Initially, optical simulations are carried out with the support of LightTools program. Next, the Mie-theory is applied to calculate and confirm the results. The calculation subjects are SEPs scattering properties within the band 455 -595 nm. The scattering results of TiO 2 suggest it is the optimal choice for pc-LEDs color quality in comparison to the other SEPs; however, it causes the luminous flux to decrease significantly along with the increase in its concentration. Besides, with the addition of SiO 2 grains, we can accomplish higher lumen output at all particle sizes. Meanwhile, the application of 30% CaCO 3 can decreas the CCT deviation by 620 K making CaCO 3 the potential particle to be selected for chromatic quality and light output enhancement of pc-LEDs.
Excellent color quality of phosphor converted white light emitting diodes wit...TELKOMNIKA JOURNAL
The remote phosphor structure is disadvantageous in color quality but more convenient in luminous flux when compared to conformal phosphor or in-cup phosphor structure. From this disadvantage, there are many studies to improve the color quality of the remote phosphor structure. This research will propose a dual-layer remote phosphor structure to improve color rendering index (CRI) and color quality scale (CQS) of WLEDs. The WLED package with color temperature of 8500 K is utilized in this study. The idea of the study is to locate a layer of phosphor green Y2O2S:Tb3+ or red ZnS:Sn2+ on the yellow phosphor YAG:Ce3+ film, and then finding the suitable added concentration of ZnS:Sn2+ to match the highest color quality. The results showed that ZnS:Sn2+ brings great benefits to increase CRI and CQS. The greater the ZnS:Sn2+ concentration is, the higher the CRI and CQS become owing to the rise in red light components in WLEDs. Meanwhile, the green Y2O2S:Tb3+ phosphor brings benefits to luminous flux. However, the decrease in luminous flux and color quality occurs when the concentration of ZnS:Sn2+ and Y2O2S:Tb3+ exceeds the corresponding level. This is proved by applying Mie-scattering theory and Lambert-Beer's law. The results of articles are important for WLEDs’ fabrication having higher white light quality.
Using SiO 2 nano-particles for better color uniformity and lumen output in 8...IJECEIAES
In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO 2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO 2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO 2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO 2 -doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO 2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO 2 -doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO 2 . These experimental outcomes suggest that SiO 2 is an effective material to add in WLEDs structure for better lighting efficiency.
Influence of Dual-layer and Triple-layer Remote Phosphor Package on Optical P...TELKOMNIKA JOURNAL
In this paper, the influence of the distance between phosphor layers in the dual-layer and triple- layer remote package on luminous flux and color rendering property is presented and analyzed. During the simulation, it is recognized that an appropriate distance can produce higher quality of the multi-chip white LED (MCW-LEDs) through adjusting the distance between two and three phosphor layers. According to the research results, 0.1mm is the outstanding distance between two phosphor layers so that the performance of MCW-LEDs can be accomplished the best optimal effect. In addition, the simulation results show that the dual-layer structure yielded higher optical properties than the triple-layer structure in relation to the distance. The highest lumen output of triple layer-structure can be achieved at the distance of 0.6 mm and dual-layer structure is 0.1 mm. Meanwhile, the color rendering index (CRI) changes insignificantly when the distance increases. Triple layer package is not practical for high power white LEDs due to high cost and low conversion efficiency. Dual-layer remote phosphor package with the distance between two phosphor layers of 0.1mm is an optimal structure of LEDs in improving the luminous efficiency and the color quality.
Na3Ce(PO4)2:Tb3+ and Na(Mg2–xMnX)LiSi4O10F2:Mn phosphors: a suitable selectio...TELKOMNIKA JOURNAL
This document discusses a triple-layer remote phosphor structure (TRP) to enhance the color quality and luminous flux of white light-emitting diodes (WLEDs). The TRP structure contains three phosphor layers arranged from bottom to top: yellow YAG:Ce3+ phosphor, green Na3Ce(PO4)2:Tb3+ phosphor, and red Na(Mg2–xMnX)LiSi4O10F2:Mn phosphor. Simulation results show that the red phosphor improves color rendering index while the green phosphor improves luminous flux but reduces color rendering index. The color quality scale is maximized when there is a balance between the yellow,
Similar to The better distant phosphor configurations for enhancing WLED color intensity: YVO4:Eu3+ and YF3:Mn2+ (20)
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
This document describes using a snake optimization algorithm to tune the gains of an enhanced proportional-integral controller for congestion avoidance in a TCP/AQM system. The controller aims to maintain a stable and desired queue size without noise or transmission problems. A linearized model of the TCP/AQM system is presented. An enhanced PI controller combining nonlinear gain and original PI gains is proposed. The snake optimization algorithm is then used to tune the parameters of the enhanced PI controller to achieve optimal system performance and response. Simulation results are discussed showing the proposed controller provides a stable and robust behavior for congestion control.
Improving the detection of intrusion in vehicular ad-hoc networks with modifi...TELKOMNIKA JOURNAL
Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
Historically, mechanical engineering has relied heavily on human expertise and empirical methods to solve complex problems. With the introduction of computer-aided design (CAD) and finite element analysis (FEA), the field took its first steps towards digitization. These tools allowed engineers to simulate and analyze mechanical systems with greater accuracy and efficiency. However, the sheer volume of data generated by modern engineering systems and the increasing complexity of these systems have necessitated more advanced analytical tools, paving the way for AI.
AI offers the capability to process vast amounts of data, identify patterns, and make predictions with a level of speed and accuracy unattainable by traditional methods. This has profound implications for mechanical engineering, enabling more efficient design processes, predictive maintenance strategies, and optimized manufacturing operations. AI-driven tools can learn from historical data, adapt to new information, and continuously improve their performance, making them invaluable in tackling the multifaceted challenges of modern mechanical engineering.
Open Channel Flow: fluid flow with a free surfaceIndrajeet sahu
Open Channel Flow: This topic focuses on fluid flow with a free surface, such as in rivers, canals, and drainage ditches. Key concepts include the classification of flow types (steady vs. unsteady, uniform vs. non-uniform), hydraulic radius, flow resistance, Manning's equation, critical flow conditions, and energy and momentum principles. It also covers flow measurement techniques, gradually varied flow analysis, and the design of open channels. Understanding these principles is vital for effective water resource management and engineering applications.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
Generative AI solutions encompass a range of capabilities from content creation to complex problem-solving across industries. Implementing generative AI involves identifying specific business needs, developing tailored AI models using techniques like GANs and VAEs, and integrating these models into existing workflows. Data quality and continuous model refinement are crucial for effective implementation. Businesses must also consider ethical implications and ensure transparency in AI decision-making. Generative AI's implementation aims to enhance efficiency, creativity, and innovation by leveraging autonomous generation and sophisticated learning algorithms to meet diverse business challenges.
https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
Digital Twins Computer Networking Paper Presentation.pptxaryanpankaj78
A Digital Twin in computer networking is a virtual representation of a physical network, used to simulate, analyze, and optimize network performance and reliability. It leverages real-time data to enhance network management, predict issues, and improve decision-making processes.
Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...shadow0702a
This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Home security is of paramount importance in today's world, where we rely more on technology, home
security is crucial. Using technology to make homes safer and easier to control from anywhere is
important. Home security is important for the occupant’s safety. In this paper, we came up with a low cost,
AI based model home security system. The system has a user-friendly interface, allowing users to start
model training and face detection with simple keyboard commands. Our goal is to introduce an innovative
home security system using facial recognition technology. Unlike traditional systems, this system trains
and saves images of friends and family members. The system scans this folder to recognize familiar faces
and provides real-time monitoring. If an unfamiliar face is detected, it promptly sends an email alert,
ensuring a proactive response to potential security threats.
Accident detection system project report.pdfKamal Acharya
The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Transcat
Join us for this solutions-based webinar on the tools and techniques for commissioning and maintaining PV Systems. In this session, we'll review the process of building and maintaining a solar array, starting with installation and commissioning, then reviewing operations and maintenance of the system. This course will review insulation resistance testing, I-V curve testing, earth-bond continuity, ground resistance testing, performance tests, visual inspections, ground and arc fault testing procedures, and power quality analysis.
Fluke Solar Application Specialist Will White is presenting on this engaging topic:
Will has worked in the renewable energy industry since 2005, first as an installer for a small east coast solar integrator before adding sales, design, and project management to his skillset. In 2022, Will joined Fluke as a solar application specialist, where he supports their renewable energy testing equipment like IV-curve tracers, electrical meters, and thermal imaging cameras. Experienced in wind power, solar thermal, energy storage, and all scales of PV, Will has primarily focused on residential and small commercial systems. He is passionate about implementing high-quality, code-compliant installation techniques.
2. protection of river banks and bed erosion protection works.ppt
The better distant phosphor configurations for enhancing WLED color intensity: YVO4:Eu3+ and YF3:Mn2+
1. TELKOMNIKA Telecommunication Computing Electronics and Control
Vol. 21, No. 2, April 2023, pp. 424~430
ISSN: 1693-6930, DOI: 10.12928/TELKOMNIKA.v21i2.24747 424
Journal homepage: http://telkomnika.uad.ac.id
The better distant phosphor configurations for enhancing
WLED color intensity: YVO4:Eu3+
and YF3:Mn2+
Ha Thanh Tung1
, Huu Phuc Dang2
1
Faculty of Basic Sciences, Vinh Long University of Technology Education, Vinh Long Province, Vietnam
2
Faculty of Fundamental Science, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
Article Info ABSTRACT
Article history:
Received Nov 29, 2021
Revised Jul 30, 2022
Accepted Dec 27, 2022
The distant phosphor configuration produces more illuminating beams than the
two settings containing conformal or in-cup phosphor. When this configuration
is used, though, it is difficult to manage the color standard of light-emitting
diodes (LEDs). As a result, in past few years, numerous studies have focused
on controlling the color standard of distant phosphor configurations. Until
present, two distant phosphor configurations of single- and triple-film
phosphor configurations, have been used to improve color standards. This
research will investigate the ideal configuration among these configurations in
terms of color rendering index (CRI), color quality scale (CQS), lumen output
(LO), as well as color homogeneity for multi-chip white LEDs (WLEDs).
WLEDs, operating at five different temperatures of color between 5600 K and
8500 K, are used to perform the studies. The results reveal that the three-sheet
phosphor setting would be more desirable, with greater CRI, CQS, and lumen
efficiency (LE) indexes. Furthermore, when using a triple-layer phosphor
arrangement, color variation is reduced, resulting in a rise in color consistency.
This conclusion is possibly verified by using Mie theory to analyze
scattering properties in distant phosphor setup, making the study findings
legitimate and important data to produce more advanced WLEDs.
Keywords:
Correlated color temperature
Mie-scattering theory
Phosphor structure
YF3:Mn2+
YVO4:Eu3+
This is an open access article under the CC BY-SA license.
Corresponding Author:
Huu Phuc Dang
Faculty of Fundamental Science, Industrial University of Ho Chi Minh City
No. 12 Nguyen Van Bao Street, Ho Chi Minh City, Vietnam
Email: danghuuphuc@iuh.edu.vn
1. INTRODUCTION
Light-emitting diodes (LEDs) are considered the next-generation luminous origin and have been
increasingly popular over the years due to their numerous benefits, including excellent illuminating efficiency,
eco-friendliness, small design, and extended lifetime [1], [2]. White LEDs are made in one of two ways: one,
by combining single-color chips of LED with multiple colors (typically blue, red, and green), and the other,
by combining said chips with phosphor, especially phosphor-converted LEDs (pcLEDs) [3]. According to the
excellent illumination performance of the following [4]-[6], the most auspicious pcLED configuration is one that
uses a blue-pumping III-nitride-based LED chip as the excitation supply and a yellow-phosphor of Ce3+
-doped
YAG (or YAG:Ce) as the illuminator. The phosphor configuration has a massive effect on pcLED
optic efficiencies, such as illuminating efficacy (IE), angular chromatic homogeneity (ACH), and chroma
rendering intent (CRI), among other things. As a result, investigators have statistically investigated the impacts
of applied phosphors on pcLEDs with regard to particle size [7], doped weight percentage [8], attenuation
coefficient [9], and structural morphologies [10]–[12]. The majority of the researchers use the Monte Carlo
method [13] to facsimile illuminating spreading within the phosphor layer, with the Mie dispersion template [14]
2. TELKOMNIKA Telecommun Comput El Control
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425
solving the optic characteristics of the phosphor. Furthermore, the Mie template necessitates the accurate setting
of various microscopic parameters throughout the simulation, some of which are difficult to obtain.
Furthermore, though the phosphor film also contains non-spherical granules, the Mie template is a precise
scattering computation for uniform globular granules [11], [15], [16]. As a result, the simulation findings for
both output blue and yellow lightings, as well as their angular dispersion, might not match the experimental
results, making it difficult to estimate the pcLEDs’ luminous intensity correctly. Zaman et al. [17] as well as
Kim et al. [18] utilized the formation containing the dual integrating sphere to analyze the radiated strength
of the transferred and reflected illumination of a YAG:Ce film under a fiber-optic guided excitation or of a
phosphor-film sequence to provide accurate optic simulation, and enhance the Mie parameters in optic
modeling for pcLEDs, respectively. Chen et al. [19] created a 1-D architecture to compute luminous
absorbance and transformation in the phosphor layer, which White et al. [20] enhanced by taking the
dispersion impact into consideration. However, the emitted illumination’s angular distribution was ignored in
the previous studies. The computed bidirectional scattering distribution function (BSDF) was developed by
Lazidou et al. [21], Zhou et al. [22] and Wei et al. [23] to quantify optic characteristics of the phosphor layer.
For the yellow and blue light distributing intensity, the simulated findings demonstrate great accord with the
experiments. Most significantly, in comparison with the Mie-theory-based bulk scattering technique, the
BSDF model can accurately predict illumination distributions with no addressing luminous scattering and
absorption activities within the phosphor-film sequence. This model is not restricted by the particle form of
doped phosphors and may significantly reduce modeling time. Li et al. [24] also presented a planar illuminating
setup applying BSDF statistics. Li et al. [24] used BSDF on a pcLED configuration to acquire an accurate
emission luminous energy result, and subsequently improved the combining gap in the module [25], [26].
Nevertheless, the prior BSDF model does not account for variable phosphor concentration and thickness,
which can have a significant impact on illumination scattering and absorption [27], [28], making it difficult to
use in pcLEDs with a variety of phosphor configurations. The optic characteristics of YAG phosphor layers
with different concentrations and thicknesses are metered in this research. On the BSDF distributions, the
effects of concentration and thickness were addressed. The obtained data was utilized to create the BSDF
model, which took into account the modifying values of phosphorus concentration and layer thickness within
the experimental range. Eventually, the model will be used in modeling a cylindrical pcLED, ensuring its
precision and efficiency.
2. SIMULATION DETAILS
2.1. Preparing essential phosphors
YF3:Mn2+
particles with an emission peak of 2.38 and 2.60 eV and emission color of green are
increasingly common in the phosphor conversion field. The factors that affect the YF3:Mn2+
phosphors’
luminescence feature include their sizes of granules as well as concentration. YVO4:Eu3+
are the second
particles to be mentioned. They have an emission peak of 2.00 eV which is known as a type of red phosphor.
It is possible to get well-prepared YVO4:Eu3+
particles by using required ingredients with precise
concentrations in mole and weight, as shown in Table 1. If YVO4:Eu3+
is to be created, a process consisting
of three main steps of firing must be strictly followed. First, combine all the ingredients by dry grinding or
milling. After that, the firing step begins by firing the materials within open quartz boats in the condition of
air under the temperature of 1000 °C within 1 hour and powderize them. And this is followed by the next two
firing steps. The second firing step is quite similar to the first step but at 1200 °C. The materials are
powdered again, washed by NaOH (or KOH) mixed with water. The products are washed for multiple times
using pure water and leave them to dry. Eventually, the final firing step takes place as the second step, also
within open quartz boats in the condition of air under the temperature of 1200 °C within 1 hour.
Table 1. Ingredients of YVO4:Eu3+
phosphor composition
Ingredient Mole (%) By weight (g)
Y2O3 95 (of Y) 107
Eu2O3 5 (of Eu) 8.8
Nh4VO3 110 129
2.2. Simulation process
The WLEDs with nine LED chips manufactured internally are used in this study, with 1.16 W
radiating power at a 453-nm peak wavelength for each chip. The single-layer distant phosphor configuration
(SL) with a yellow phosphor layer YAG:Ce3+
coating the outside of LED chips is shown in Figure 1(a).
Figure 1(b) shows a triple-layer distant configuration (TL) with a YF3:Mn2+
phosphor layer placed between
two additional phosphor layers.
3. ISSN: 1693-6930
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(a) (b)
Figure 1. Multi-layer phosphor packages’ simulation for WLEDs: (a) Single-layer phosphor and
(b) triple-layer phosphor
All sheets of phosphor are 0.08-mm thick. If we want to sustain the correlated temperature colors
(ACCTs) at an average level, the concentration of YAG:Ce must be modified when the red or green phosphor
concentration varies. It’s also worth noting that the YAG:Ce concentrations differ depending on which ACCT
is used and which phosphor configuration is used. As a result of this, the scattering characteristics of LEDs
differ, resulting in a wide range of optic features.
Figure 2. Concentrations of YAG:Ce phosphor in TL
and SL setups for every average CCT
Figure 3. The intensity of emission in TL and SL
setups
Figure 2 shows that the yellow YAG:Ce3+
phosphor concentration performs outstanding increases at
every ACCT level in the SL configuration but the greater reduced amounts in the TL configuration. When all
distant phosphor configurations are examined at a given ACCT, the greater the YAG:Ce3+
content probably
leads to more occurring back-scattering, and the illuminating beam reduces as a consequence. On the other
hand, as said content reaches a significant level, a disparity between the three major hues that create the light
of white (yellow, red, and green) emerges, resulting in a loss of uniformity in color re-creation in the WLED
device. For the task of acquiring superior illuminating beam as well as reproducing hue features in the WLED
device, obtaining a decrease in back-scattering and maintaining the sufficiency and equal distribution of three
hues of yellow, red, and green elements are significantly critical. Furthermore, raising the red spectra could
support the CRI value, while the green spectra can affect color homogeneity and illuminating beam. Given the
aforementioned possibilities, the triple-layer phosphor looks to be the best configuration for regulating optic
features, doesn’t it? the group of researchers continues to provide essential information linked to distant
phosphor configurations, namely the emission spectrum, in order to address this question. As demonstrated in
Figure 3, the emission spectrum of distant phosphor configurations differs noticeably. When contrasted with
the other distant phosphor configurations at five distinct ACCTs, the emission spectra of the SL layout have
the minimum luminosity. This proves that the SL layout is inferior to the TL in terms of illuminating beam
intensity. Moreover, the TL configuration produces the best spectrum strength from 380 nm to 780 nm.
3. RESULTS AND DISCUSSION
It is possible to draw a comparison between the CRI of TL and SL setups using the data in Figure 4.
Apparently, regardless of ACCT values, the TL configuration obtains the maximum CRI. The CRI value rises
in tandem with the growth in ACCT, reaching its greatest point under a temperature of 8500 K. The finding
could be critical when it comes to augmenting the CRI of WLEDs using distant phosphor configurations.
4. TELKOMNIKA Telecommun Comput El Control
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427
Moreover, the TL thrives at managing CRI at high ACCT (exceeding 7000 K), which might be a challenge to
achieve. The TL configuration would be outstanding in terms of CRI benefits, or the mono-layer structure’s
(SL) CRI is relatively lower. Based on these findings, it can be stated that the TL configuration is the best
choice for mass-produced WLEDs if the aim is CRI. Despite this, CRI can access only one aspect of color
reproduction. An in-depth assessment of chromatic reproduction effects required more than a good CRI.
In the past few years, numerous studies have focused on a new indicator termed CQS, which is a composite of
CRI, viewer’s taste, and chromatic coordinates. CQS has been deemed the most essential indicator in assessing
color rendering intent and color reproduction efficiency, making it a significant and desirable achievement. CQS
of distant phosphor configurations is contrasted in this research and displayed in Figure 5. The TL obviously
displays the more excellent CQS results, which might be because of its greater CRI. The equilibrium of three
fundamental colors: yellow, green, and red, demonstrates this outcome. If the color standard is better, the CQS
value will be higher. In the meantime, unlike the CRI, the CQS value for the SL layout is largely different,
specifically, much lower than the other. Generally, the SL benefits illuminating beam but not color standard
control unless green and red-light portions are introduced. Although the SL layout has a downside in terms of
color intensity, it is advantageous in terms of manufacturing because it is easier to produce and costs less
than the remaining configurations.
It may be concluded from the results in Figure 4 that if color standards are the primary goal for
producers, choosing the TL configuration can be considered. On the other hand, we need to be concerned
with whether the illuminating beam becomes impacted if the color intensity is improved. To address this
issue, the research group is contrasting the illuminating beam created by single-layer and dual-layer
configurations. This part will give the present an explanation based on the math solution for transferred blue
illumination as well as transformed yellow illumination for an SL and a dual-sheet (DL) (for the
simplification of the mathematic system). This model also shows that a DL configuration can result in a
significant increase in LED luminosity, meaning using more distant phosphor sheets can help increase the
white-light emission intensity of the pcLED.
Figure 4. Color rendering indexes in TL and SL setups
for every average CCT
Figure 5. Color quality scale in TL and SL setups
for every average CCT
The following expressions are used to compute the transferred blue illumination as well as transformed
yellow illumination for the SL setup having a phosphor sheet breadth measured at 2ℎ in (1) and (2) and in the
DL setup with a phosphor sheet breadth measured at ℎ in (3) and (4).
𝑃𝐵1 = 𝑃𝐵0 × 𝑒−2𝛼𝐵1ℎ
(1)
𝑃𝑌1 =
1
2
𝛽1×𝑃𝐵0
𝛼𝐵1−𝛼𝑌1
(𝑒−2𝛼𝑌1ℎ
− 𝑒−2𝛼𝐵1ℎ
) (2)
𝑃𝐵2 = 𝑃𝐵0 × 𝑒−2𝛼𝐵2ℎ
(3)
𝑃𝑌2 =
1
2
𝛽2×𝑃𝐵0
𝛼𝐵2−𝛼𝑌2
(𝑒−2𝛼𝑌2ℎ
− 𝑒−2𝛼𝐵2ℎ
) (4)
Where ℎ denotes the thickness for every phosphor sheet in the distant phosphor setups; the subscripts “1” and
“2” denote SL and DL setups, respectively. When blue illumination is transmuted into yellow illumination,
𝛽 represents the transformation coefficient. 𝛾 is the yellow-illumination reflection coefficient. The optical
power generated by the LED in blue will be represented via the blue illumination (𝑃𝐵) as well as yellow
illumination (𝑃𝑌) intensities, both of which will be indicated via 𝑃𝐵0. The optical energy loss in the lighting
propagation within the setups are indicted by 𝛼𝐵 for blue illumination as well as 𝛼𝑌 for yellow illumination.
5. ISSN: 1693-6930
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The illumination effectiveness for a pcLED is clearly higher with a DL configuration than with a SL
configuration:
(𝑃𝐵2+𝑃𝑌2)−(𝑃𝐵1+𝑃𝑌1)
𝑃𝐵1+𝑃𝑌1
> 0 (5)
At the same time, Mie dispersion hypothesis [29] is employed for the task of calculating the
dispersion coefficients and cross section of spherical phosphor granules in phosphor films. Then, we can
employ the law of Lambert-Beer [30] for the task of determining the transferred illumination energy.
𝐼 = 𝐼0𝑒𝑥𝑝(−𝜇𝑒𝑥𝑡𝐿) (6)
For (6), 𝐼0 and 𝐼 represent the incident illumination (strength and the transferred illumination energy,
respectively. 𝐿 exhibits the breadth for a phosphor sheet in millimeters). µ𝑒𝑥𝑡 indicates the attenuation
coefficient. The expression for calculating attenuation coefficient is: µ𝑒𝑥𝑡 = 𝑁𝑟 × 𝐶𝑒𝑥𝑡, with 𝑁𝑟 (mm-3
) and
𝐶𝑒𝑥𝑡 (mm2
) correspondingly determine the density allocation number and the extinction cross-section for
phosphor spheres. The (5) shows that a system with many phosphor layers improves illuminating beam
more than a single layer configuration. This finding is further supported by Figure 5, which shows that the SL
configuration has the least illuminating beam of the four configurations at all ACCTs. On the contrary, the TL
configuration posseses the biggest light ray. Though it obtains the best producing color display, the outcome
dispels any questions regarding the beneficial degree of TL configuration. As the YAG:Ce3+
concentration
decreases, the TL configuration minimizes the quantity of backscattered illuminations. Furthermore, blue LED
chip lights may effortlessly bypass the YAG:Ce3+
sheet, going towards the remaining sheets. As such, the TL
configuration efficiently converts the blue illumination output generated by chips in LED. As a consequence,
the TL configuration has the maximum spectrum strength in the white light wavelength region, resulting in the
most illuminance.
Figure 6. Lumen output (LO) in TL and SL setups
for every average CCT
Figure 7. CCT deviation (D-CCT) in TL and SL
setups for every average CCT
Because of the excellent optic characteristics of WLEDs, such as CQS and LE value, the TL
configuration can be adopted. It should be noted that color homogeneity cannot be overlooked when color standard
is the objective. Color homogeneity can be improved in a variety of ways, including the use of enhanced
scattering particles and conformal phosphor design. Although chromatic constancy is improved, the illuminating
beam may be reduced as a result of these two procedures. Using the green YF3:Mn2+
phosphor and the red
YVO4:Eu3+
phosphor improves the white illuminating intensity by increasing the scattering characteristics and
the additional green or red elements within the WLEDs, see Figure 6. Furthermore, the utilization of distant
phosphor configurations improves illuminating performance by minimizing light reflection to the surface
of LED chips. However, in order to produce the best transferred energy, the phosphor layer concentration
should be regulated to an optimum level. The Lambert-Beer law in (6) proves this. The color divergence of
distant phosphor configurations is compared in Figure 7. If the color consistency is stronger, the color
divergence will be reduced. The color divergence value of the TL configuration is the lowest, as seen in the
figure. This outcome can be proven by the scattering event that occurs within the LED packet before the light
of white is formed. The more phosphor layers there are, the more dispersion occurs, which improves color
consistency. However, increased scattering events can result in a reduction in luminance. This decrease,
6. TELKOMNIKA Telecommun Comput El Control
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however, comparing to the benefits gained by minimizing backscattering, can be seen as a small sacrifice.
The reduction in backscattering is vital to both color reproduction efficiency and the function of the
conversion phosphors. Accordingly, the TL configuration may achieve the greatest color consistency while
maintaining the greatest light intensity. Besides that, for all ACCTs, the SL layout has the biggest color
variation, indicating the large difference in color display of its white light.
4. CONCLUSION
Finally, for five distinct ACCTs, this paper examines the optic effectiveness of two remote-layer
phosphor configurations: SL and TL. Additionally, the modeling procedure utilizes green YF3:Mn2+
phosphor and red YVO4:Eu3+
phosphor. The Mie hypothesis as well as the law of Lambert-Beer are also used
for the task of verifying the outcomes of the investigation. Based on these findings, complementing green
LEDs with the green phosphor layer YF3:Mn2+
improves color consistency and output luminosity. It’s clear
that the color re-generation efficiency is determined by the proportions of three fundamental colors including
blue, green, red, and yellow. It is possible for the TL configuration to uniformily regulate these primary
colors on the chroma scale. Furthermore, the decrease of backscattering in TL enables a significant rise in its
illuminating beam. The largest value of light intensity comes from the TL configuration, which supports this
conclusion. Producers can simply choose the most appropriate configuration that matches their needs relying
on the findings of this study for the task of augmenting the efficiency for their WLED products.
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BIOGRAPHIES OF AUTHORS
Ha Thanh Tung received the PhD degree in physics from University of Science,
Vietnam National University Ho Chi Minh City, Vietnam, he is working as a lecturer at the
Faculty of Basic Sciences, Vinh Long University of Technology Education, Vietnam. His
research interests focus on developing the patterned substrate with micro- and nano-scale to
apply for physical and chemical devices such as solar cells, OLED, photoanode. He can be
contacted at email: tunght@vlute.edu.vn.
Huu Phuc Dang received a Physics Ph.D degree from the University of Science,
Ho Chi Minh City, in 2018. Currently, he is a lecturer at the Faculty of Fundamental Science,
Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam. His research interests
include simulation LEDs material, renewable energy. He can be contacted at email:
danghuuphuc@iuh.edu.vn.