The document discusses white LED technology, detailing its revolutionary role in modern lighting, including an overview of its principles, generation methods, and manufacturing processes. It highlights the advantages, such as energy efficiency and longevity, while also addressing challenges and disadvantages like blue light hazard and initial costs. The presentation emphasizes the significance of white LEDs in various applications, alongside contributing factors like quality checks and alternatives to traditional lighting sources.

1. WHITE LED
THE FUTURE LAMP

2. WHITE LED: THE FUTURE LAMP
A presentation by :
Sunanda Chakraborty (Roll # 118)
&
Kalyan Bosu (Roll # RL129)
Branch: ECE
Semester: 6

3. Content:
• Introduction
• Nobel Award on white LED
• Normal LED: Working Principle
• Generation of White LED
• Manufacturing
• Quality Check: Basic Parameters
• Uses and Applications
• Advantages and Disadvantages
• Conclusion

4. Introduction
LED goes to revolutionize the lighting technology of
modern era.
Fourth and latest generation of light sources
The white LED lamp is equivalent to 60 watt
incandescent bulb in size and brightness but lasts 25
times longer and runs on less than 10 watts

5. Isamu Akasaki and Hiroshi
Amano at Nagoya
University, Japan, and Shuji
Nakamura of the University
of California at Santa
Barbara have won the Nobel
prize in physics for the
invention of blue light-
emitting diodes – an energy-
efficient and environment-
friendly light source.

6. LED Basics

7. Working Principal of Basic LED
The LED is a semiconductor diode that emits light
when current passes through it
The n-side is heavily doped
When forward biased, the built-in potential at the
junction is reduced
The e-
from n-side get injected into p-side
 e-
combine with the holes resulting in emission of
photons i.e. light
This effect is called electroluminescence

8. Colours

9. Generation Methods of White Light
RGB synthesis
Using Blue LED with
phosphor coating
Other methods include
growing zinc selenide (ZnSe)
on a ZnSe substrate which
simultaneously emitted blue
light from diode and yellow
light from substrate

10. Processing

13. Basic parameters
Efficacy 80-160 lm/watt
Input power 2-100 watts
Color rendering index (CRI) 65-97
Correlated color temperature 2700-8000 k
Life time in hours 50,000 hours

14. Challenges
Electrical compatibility
LEDs run on dc voltage
To run from mains, miniaturized circuitry that
converts AC to DC is provided between supply and device
Thermal management
Heat sinks
Fans for cooling
Graphite foam

15. Thermal Management

16. Popular Usage of White LED:
Incandescent bulbs
Fluorescent bulbs
High intensity
discharge(HID) lamps

17. Applications
 Street and
outdoor lighting
 Architectural
lightning
 Down lights
 Freezer case
lighting
 Retail display
lighting
 Horticulture
lighting
 Portable lighting

19. Advantages
Small in size
High photoelectric conversion
efficiency
Ideal for cycling in lights
Longer life time compared to
other light sources
Do not contain toxic materials
such as mercury
Can be designed to emit light
of intended colour
Radiate very little heat
Can be dimmed

20. Disadvantages
Exceeds the safety limits of blue-light hazard
Temperature dependent
Causes more light pollution than other light sources
Voltage sensitive
High initial prices
Under cool-white LED illumination, the colour of the
objects is perceived differently

22. Thank You