The era of lamp photobiological safety standards coincided with a proliferation of solid state lighting applications, which led to much discussion on the retinal blue light hazard posed by these sources and much confusion in the interpretation of the EN 62471 standard.
Driven by the desire to circumvent issues encountered in applying this standard, and to reduce the measurement burden of luminaire manufacturers, a new approach to the evaluation of the photobiological safety of luminaires is now in place, according to the latest edition of the luminaire standard, EN 60598-1.
Whilst the new approach includes techniques to perform an analysis based on readily available information, in accordance with the reduction of measurement burden, it will be seen that this approach may lead to overly conservative results. It will also be shown that, in the analysis of sources with high blue light radiance, the determination of hazard distance may in many cases be over-estimated.
Hazard distance is rarely readily calculable for extended sources and determination by measurement can be cumbersome but can give a well-defined framework of assessment which will dispel the interpretations and uncertainties that has plagued lamp photobiological safety standards hitherto. A simple measurement-based approach is proposed.
Talk by Leslie Lyons MPhys, Bentham Instruments Limited
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Download luận văn đồ án tốt nghiệp với đề tài: Triển khai các mạng quang WDM cho phép truyền dẫn lưu lượng IP, cho các bạn làm luận văn tham khảo
Nhận viết luận văn đại học, thạc sĩ trọn gói, chất lượng, LH ZALO=>0909232620
Tham khảo dịch vụ, bảng giá tại: https://baocaothuctap.net
Download luận văn đồ án tốt nghiệp với đề tài: Triển khai các mạng quang WDM cho phép truyền dẫn lưu lượng IP, cho các bạn làm luận văn tham khảo
This presentation is about Optical detector (APD) of a specific commercial model and what does it do with addition to Laser Diode and it’s commercial use also from a specific model
Fast Thermo-Optic Optimization of High-Order SOI Microring Optical Filters be...TylerJamesZimmerling
We experimentally demonstrated a fast optimization algorithm based on the method of gradient descent for
achieving optimum spectral response of high-order silicon microring optical filters. The filter optimization was
performed on a 4th-order serially-coupled silicon microring filter by thermo-optically tuning the microring resonances using Ti/W heaters. Three different optimization objective functions were used to obtain the optimum
filter shape, namely, the single-wavelength method, the dual-wavelength method, and the total transmitted power
method. The efficacy of each optimization method was evaluated and compared based on the number of required
iterations, the ideality of optimized response, and the wavelength tuning accuracy.
How do we re-think lighting in a way that has a lower impact on the environment, while still fulfilling human needs?
How do we implement our good intentions in real life?
Gladsaxe municipality needed a lighting solution that affected a nearby bat colony as little as possible, while maintain safety on the bicycle path running through a wooded area. Taking point of departure in this case, we discuss how lighting professionals should work to translate scientific research and technical knowledge into innovative site specific projects with the lowest possible environmental impact.
Talk by: Philip Jelvard and Rune Brandt Hermannsson, Light Bureau
This presentation is about Optical detector (APD) of a specific commercial model and what does it do with addition to Laser Diode and it’s commercial use also from a specific model
Fast Thermo-Optic Optimization of High-Order SOI Microring Optical Filters be...TylerJamesZimmerling
We experimentally demonstrated a fast optimization algorithm based on the method of gradient descent for
achieving optimum spectral response of high-order silicon microring optical filters. The filter optimization was
performed on a 4th-order serially-coupled silicon microring filter by thermo-optically tuning the microring resonances using Ti/W heaters. Three different optimization objective functions were used to obtain the optimum
filter shape, namely, the single-wavelength method, the dual-wavelength method, and the total transmitted power
method. The efficacy of each optimization method was evaluated and compared based on the number of required
iterations, the ideality of optimized response, and the wavelength tuning accuracy.
How do we re-think lighting in a way that has a lower impact on the environment, while still fulfilling human needs?
How do we implement our good intentions in real life?
Gladsaxe municipality needed a lighting solution that affected a nearby bat colony as little as possible, while maintain safety on the bicycle path running through a wooded area. Taking point of departure in this case, we discuss how lighting professionals should work to translate scientific research and technical knowledge into innovative site specific projects with the lowest possible environmental impact.
Talk by: Philip Jelvard and Rune Brandt Hermannsson, Light Bureau
It’s clear that the lighting industry needs to take a lead in providing solutions that both respect the environment and protect our dark skies, but how do we balance this with the differing requirements of the people who use those spaces? Whilst we focus on ‘numbers’ and provide schemes that meet the standards and minimise ecological impact does this result in spaces that may not be inclusive by design?
And how can we deliver engaging places and spaces that people love to be in?
This paper explores how technology can help support a more holistic approach that meets both needs.
By Clare Thomas, Urbis Schreder.
Decarbonisation is one of the greatest challenges facing our generation and Distribution Network Operators (DNOs) sit at the heart of the transition to Net Zero. With millions of Electric Vehicles (EVs) charging at home, on the street and at work, often using as much power as a block of flats, DNOs will need to work with customers and stakeholders to build a smart, flexible network.
In this webinar we will examine our forecasts for the likely EV uptake, how DNOs will need to support customers wanting to connect to the electricity supply network and how innovation is helping them connect customers more quickly and cheaply.
Speaker: Neil Madgwick, UK Power Networks.
This CPD webinar covers the need for a Circular Economy and describes an ideal one. Legislation and guides relevant to the lighting industry are outlined. Circular Design principles are examined related to luminaire design, materials, manufacturing and ecosystem. As a coda the Circular Economy is put into a wider environmental impact assessment context.
Talk by Roger Sexton, Business Development at Stoane Lighting
The drive towards delivering a Net Zero economy is ramping up and now more than ever we need to take action in all aspects of our daily lives to reach this goal. But as lighting designers, how can we make this change when essentially specifying energy using products is what we do. So where do we start when embarking on this journey and importantly how can we limit our impact on the environment when delivering lighting projects?
Kristina will present the Society of Light and Lighting's (SLL) TM66 - 'Creating a Circular Economy in the Lighting Industry' with an accompanying metric - Circular Economy Assessment Method (CEAM). This will help everyone on their journey in creating a circular economy in the lighting industry.
Presented by Kristina Allison, SLL and Lighting Designer, Atkins Global.
Alec will introduce an overview of LCRIG and its aim to deliver practical solutions to help councils achieve net zero. Stressing the importance of removing silos both in the public and private sector, Alec will show how the lighting sector can team up with others. He will reveal the creation of a net zero working group which ILP members can get involved with.
Presented by Alec Peachey, Content Director, Local Council Roads Innovation Group.
“In order to be irreplaceable, one must always be different” - Coco Chanel.
Sharon and Martin talk about how and why they deliberately set up Light Collective using a different model to conventional lighting consultancies (they made their own one up!). They share their journey to date and how they shifted from lighting designers to light activists to create a unique creative consultancy (they don't know what else to call it!). Never be afraid of being different, be afraid of being the same as everyone else…
www.lightcollective.net
Presented by
Sharon Stammers and Martin Lupton - Light Collective.
We look at how the colour of surfaces within a space lit with LED lighting influences our perception of size and height, what is the first colour seen by infants and how their colour perception range grows, the influence of other colours in our daily lives, art, religion, cars, farming, and more. This is not what you would expect about colour.
Presented by
Philip Hammond - Director and Principal, BHA School of Lighting - Cape Town, South Africa.
and
Lorraine de Bruyn - Lighting Executive, Perspex SA, and student BHA School of Lighting - Johannesburg, South Africa.
We take a very different look at colour, how colour is perceived in different cultures around the world, how your choice of colour for your business brand can influence and be interpreted by your customers, iridescence and more.
Presented by
Philip Hammond - Director and Principal, BHA School of Lighting - Cape Town, South Africa.
and
Abinaya Jevaraju - Electrical & Electronics Engineer, and second year student BHA School of Lighting - Kuwait City, Kuwait.
With 80% of the built environment already in existence today, the choices we make in delivering low carbon, environmentally considered solutions must go beyond simply considering the operational efficiency of an installation. This presentation will look at what good lighting looks like for an existing space and how we can utilise already installed assets to deliver the lowest carbon impact without compromising on the needs of people.
Presented by Tim Bowes MSLL, Head of Lighting Application at Whitecroft Lighting.
Overview of technical challenges within Smart Light Concepts (SLIC) project.
In the European research project Smart Light Concepts (SLIC), researchers from Avans University of Applied Sciences and Portsmouth University explore, together with city and provincial authorities in 4 countries (Belgium, France, the Netherlands and United Kingdom), different solutions for reducing carbon emissions from public lighting.
The focus of this talk was on:
• (preliminary) results regarding energy and CO2 emissions reduction achieved by the various pilot projects
• Quantification of diminishing returns of different energy usage reduction strategies
• Differences in Public Lighting approach between different (ex) EU member states
• Technology related success & failure factors in public lighting projects
Find out more about the SLIC project here.
Speaker: Yves Prevoo, Avans University of Applied Sciences.
Hosts: Claire Gough, Chair ILP Bristol and Tom Lewis, Vice Chair ILP Bristol.
This presentation was presented as an ILP CPD webinar in August 2021 the recording is available at www.theilp.org.uk
The role of public lighting is twofold, it has to make the night time environment both safe and appear to be safe. This is not that straight forward as the perception of safety is not directly related to actual safety. The feeling of safety is dependent on a whole series of factors including personal history, location and time. Whilst it is clear that darkness reduces feelings of safety it is less obvious what is the best way to provide light to improve safety.
Speakers: Dr Jemima Unwin MSc PhD RIBA MSLL and Professor Peter Raynham CEng FILP FSLL MCIBSE, from UCL Institute for Environmental Design and Engineering (IEDE)
A session on lighting and planning, delivered by two planning policy officers from nationally protected landscapes. Paul Fellows is Head of Strategic Planning at North York Moors National Park Authority, which along with the Yorkshire Dales National Park was granted International Dark Skies status in December 2020. Natalie Beal is a policy planner at the Broads Authority. Both are Members of the Royal Town Planning Institute. Natalie and Paul will deliver an hour long session that will be in three parts. Firstly, an introduction to how the planning system works. They will then focus on how lighting can be influenced through the planning system. Finally, they will give a planner’s view on the 10 policy proposals from the Dark Skies APPG.
Speakers: Natalie Beal MRTPI, Broads Authority and Paul Fellows MRTPI from North York Moors.
An experienced street lighting team’s perspective -
Scotland has a strong focus on accelerating the provision of electric vehicle charging infrastructure. Data shows that outside of London, Scotland is way ahead of the rest of the UK in the provision of public charge points. So, what can be learnt from Westminster’s EV charging rollout? The process has been managed by a specific team, with technical input from the council’s street lighting team. This CPD presentation will give the street lighting team’s view of the in-column EV charging rollout in the council. Covering the expectations versus reality under current standards, the issues found following installation, and the ever-changing landscape of what can be allowed on the highway, this session will benefit every street lighting professional with an involvement in EV charging. The webinar will also include an overview of the issues to consider with rapid chargers.
Speaker: Dean Wendelborn BE(Civil) and Dip.Lighting (LET), Westminster City Council
Road Lighting Standards for Europe and beyond, a personal reflection.
Join ILP Ireland on a world tour, headlined by Nick Smith. You might think the European road lighting Standards would be applied the same way across all of Europe but that isn’t the case. This webinar will discuss how EN13201 is applied in various European countries and their thinking behind this. The webinar will then focus on America, looking at their approach to lighting design in USA and Canada; the Standards used, the design metrics and how they are applied. Next on the world tour will be Australia and New Zealand, again, looking at their Standards, the metrics and how they are applied. The final stop will be the middle east where a range of Standards are applied.
The world becoming less isolated with improved communications so designing for overseas clients will become more commonplace in future. This is a must see webinar for all those involved in lighting design.
Speaker: Nick Smith FILP IEng MIES, Nick Smith Associates Limited
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This presentation, created by Syed Faiz ul Hassan, explores the profound influence of media on public perception and behavior. It delves into the evolution of media from oral traditions to modern digital and social media platforms. Key topics include the role of media in information propagation, socialization, crisis awareness, globalization, and education. The presentation also examines media influence through agenda setting, propaganda, and manipulative techniques used by advertisers and marketers. Furthermore, it highlights the impact of surveillance enabled by media technologies on personal behavior and preferences. Through this comprehensive overview, the presentation aims to shed light on how media shapes collective consciousness and public opinion.
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Insight: In a landscape where traditional narrative structures are giving way to fragmented and non-linear forms of storytelling, there lies immense potential for creativity and exploration.
'Collapsing Narratives: Exploring Non-Linearity' is a micro report from Rosie Wells.
Rosie Wells is an Arts & Cultural Strategist uniquely positioned at the intersection of grassroots and mainstream storytelling.
Their work is focused on developing meaningful and lasting connections that can drive social change.
Please download this presentation to enjoy the hyperlinks!
7. www.bentham.co.uk
The Case of Lamps and Luminaires
•Which sources considered GLS?
•Result of majority of GLS evaluations: Exempt
•500 lux may not represent realistic exposure
scenario
The GLS approach led to concerns
within the lighting industry
8. www.bentham.co.uk
“New” Approach
•Actinic UV hazard (2 mW.klm-1)
•IR Hazard (marking only)
•Blue Light Hazard implementing IEC TR 62778 :
“Application of IEC 62471 for the assessment of
blue light hazard to light sources and luminaires”
IEC TC 34 New approach based on
lamp type considering:-
9. www.bentham.co.uk
Photobiological Safety in Vertical Standards
Standard UV Blue IR
60432-1 Ed 2.2 Tungsten filament lamps for domestic and similar general lighting
purposes
N N N
60432-2 Ed.2.2 Tungsten halogen lamps for domestic and similar general lighting
purposes
N N N
60432-3 Ed 2 Tungsten halogen lamps (non-vehicle) Y N Y
60968:Ed 3 Self-ballasted lamps for general lighting services Y N N
61195 Ed 2.2 Double-capped fluorescent lamps Y N N
61199 Ed 3.2 Single-capped fluorescent lamps Y N N
62035 Ed 2 Discharge lamps (excluding fluorescent lamps) Y Y N
62031 Ed 2.2 LED modules for general lighting Y Y N
62560 Ed 1 Self-ballasted LED-lamps for general lighting services by voltage > 50 V Y Y N
62776 Ed 1 Double-capped LED lamps for general lighting services Y Y N
62663-1 Ed 1 Non-ballasted LED-lamps Y Y N
60598-1 Ed 8 Luminaires Part 1: General requirements and tests Y Y N
10. www.bentham.co.uk
IEC TR 62778
Considers only blue light hazard of component lamps/ LEDs and finished product luminaires
RG1 considered “safe”
Determine if blue light hazard RG1 or below at 200mm
Significant driver to reduce measurement burden for luminaire manufacturers
12. www.bentham.co.uk
Time Dependence of Retinal Irradiance
IncreasingExposureTime
Exposure
Time (s)
Angle of Acceptance
(mrad)
<0.25 1.7
0.25-10 11√(t/10)
10-100 11
100-10000 1.1√t
>10000 100
13. www.bentham.co.uk
Blue Light Hazard RG1
Risk group definitions from IEC 62471
Risk
Group
Blue Light Hazard
No Hazard within
(s)
Acceptance Angle
(mrad)
Limit
(W.m-2 .sr-1)
Exempt 10000 100 100
Group 1 100 11 10000
Group 2 0.25 1.7 4000000
11mrad = 0.063°
16. www.bentham.co.uk
Blue Light Hazard Efficacy of Luminous
Radiation
• KB,V = EB/Ev= LB/Lv
• EB, LB blue light irradiance/ radiance
• EV, LV illuminance/ luminance
17. www.bentham.co.uk
Possible Assessment Results
Component Lamps or LEDs Finished Products
RG0 unlimited (very rare) RG0 (very rare)
RG1 unlimited RG1
Ethr
Threshold illuminance (lx) at which RG1 found
dthr
Threshold distance (m) at which RG1 found
Risk
Group
Blue Light Hazard
No Hazard within
(s)
Acceptance Angle
(mrad)
Limit
(W.m-2 .sr-1)
Exempt 10000 100 100
Group 1 100 11 10000
18. www.bentham.co.uk
Origin of Ethr
Consider blue light radiance in 11mrad FOV as irradiance , E11=L11. Ω11
RG1 blue light irradiance limit = 1 W.m-2
Use KB,V = EB/EV, set EB = 1 W.m-2, EV = Ethr
Ethr= 1/ KB,V
19. www.bentham.co.uk
Conditions for Transfer of Data
Small source, <2.2mm,
FOV under-filled
Large source, >2.2mm,
FOV over-filled
Component Lamps or
LEDs
RG0 unlimited (very rare)
RG1 unlimited
Ethr
Threshold illuminance (lx) at
which RG1 found
20. www.bentham.co.uk
One TR, Two Methods
In order of accuracy and effort…
Method A
Minimum Input
Method B
Highest Accuracy
CCT CCT and luminance Source dimensions
Spectral radiance (300 nm to 780 nm)
Ethr RG0 (unlimited)
RG1 (unlimited)
Ethr
RG0 unlimited
RG1 (unlimited)
Ethr
Includes safety factor 2
Over estimation of the hazard
None
21. www.bentham.co.uk
Limits and Classifications- Source ≥ 2.2mm
Result
(W.m-2.sr-1)
Assessment
Component Lamp/ LED Finished Product
LB <100 RG0 Unlimited RG0
LB < 10000 RG1 Unlimited RG1
LB ≥10000 Report Ethr Report dthr
• Spectral Radiance in 11mrad FOV at 200mm 300-780nm
22. www.bentham.co.uk
Limits and Classifications- Source < 2.2mm
In practice no
luminaires will be so
small!
Result
(W.m-2)
Assessment
Component Lamp/ LED Finished Product
EB < 1 Report Ethr RG1
EB >1 Report Ethr Report dthr
• Spectral Irradiance at 200mm 300-780nm
23. www.bentham.co.uk
Technique to Find dthr
Find the peak intensity, Ip (cd) , (obtained from goniophotometric data)
Ensure normalised intensity data (cd/klm) multiplied by luminaire luminous flux to obtain intensity
Determine dthr from dthr = √( Ip/Ethr )
Validity of use of inverse square law in question
25. www.bentham.co.uk
Determination of Realistic dthr
Annex D attempts to guide user towards a validation/ refinement of dthr
Includes guidance to determine dthr for one emitter of an array- how to realise this?
Determination of a realistic dthr will represent a significant challenge
28. www.bentham.co.uk
Spatially averaged radiance reduction factor typically 2-8 times
Considering overlap of FOV and LED emission area, require from √2 to √8 distance
Increased distance where multiple emitters fall within FOV
Reduction due to proportion of beam falling in pupil solid angle to be considered
Reduction Factor Required
Given typical radiance of current LED technology…
Source Blue Light Radiance
(W.m-2.sr-1)
6500K White PC-LED ~2x 104
Blue LED ~8x 104
29. www.bentham.co.uk
Omni-Directional Sources
It is likely that the computed value of dthr be overly conservative
Repeat spectral radiance measurement at 400mm and where required 600mm
It is not expected that dthr exceed this value except for blue LEDs
Report as dthr the minimum distance at which LB<10 000 W.m-2.sr-1
30. www.bentham.co.uk
Directional Sources
The narrower the beam angle, the greater dthr
Evaluate whether or not the source extends beyond circle of diameter 0.011.dthr
Repeat spectral radiance measurement at multiples of 0.5m below dthr
31. www.bentham.co.uk
Evolution of LED Techology
Some propose violet LED pumped PC-LEDs in lieu of blue LED pump ostensibly to render objects as
sunlight
Consideration should be given to the aphakic eye
Pump Blue Light
Radiance
(W.m-2.sr-1)
Aphake
Radiance
(W.m-2.sr-1)
405nm ~1.1x 104 ~1.9x 104
450nm ~1.5x 104 ~1.5x 104
32. www.bentham.co.uk
The Last Word
•The measurement procedure is simplified…. until RG1 limit exceeded!
•A measurement-based refinement of dthr will avoid excessive over-estimation
Product standards in lighting applications now consider
photobiological safety
•Please fire away...
•Or email llyons@bentham.co.uk
Any Questions?
Thank You for your attention
Editor's Notes
Measurement FOV should correspond to exposure time of risk group considered
Apply pass/ fail proceeding from Exempt risk group
It is presumed that in measuring the spectral radiance in 11mrad FOV at 200mm true radiance will be measured
Where the true radiance of the source can be measured, data may be passed from component lamp/ LED to finished product
Source smaller than 2.2mm diameter circle
Measurement FOV should correspond to exposure time of risk group considered
Apply pass/ fail proceeding from Exempt risk group
Measurement FOV should correspond to exposure time of risk group considered
Apply pass/ fail proceeding from Exempt risk group