My INSURER PTE LTD - Insurtech Innovation Award 2024
White led
1.
2. Introduction
Working of LED
How is white LED
light made with LED
White LED structure
Application
Advantages
Disadvantages
Conclusion
3. Light emitting diode known as LED in the electronic
industry are poised to replace all conventional light
sources .The LED is simply a semiconductor diode that
emits light when an electric current is passed through
it.
It is fourth and latest generation of light sources.
The white LED lamp is equivalent to 60watt
incondescent bulb in size and brightness but lasts 25
times longer and runs on less than 10watts.
4. 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
The e- combine with the holes resulting in
emission of photons I,e light
This effect is called electroluminescence.
5. Now a time there are two ways of making white LED
1.MIXED COLOUR LIGHT
When red ,blue and green LED located adjacent to one
another and the amount of their out put mixed
properly the resultant light is white.
2.USING BLUE LED WITH PHOSPHOR COATING
When we incorporate the phosphor in the body of a
blue led with a peak wavelength around 450to470
nanometers some of the blue light will become yellow
and some will mix with that yellow light will become
white.
8. Street and outdoor lighting
Freezer case lighting
Landscape ,market
,decoration , lawn ,home ,
public places lighting etc.
Back light in cell phones,
computer , electronics etc.
Special lighting and military
use
It is also applied in toys ,
gifts , flash light etc.
9. Small in size
Longer life time compare to other
electric source
Do not contain toxic materials such as
mercury
Radiated very little heat
Good stability
10. White LED prices are higher than that of
incandescent bulb
Temperature dependent
Cause more light pollution than other
light sources
Under cool white LED illumination the
colour of the objects is perceived
differently
11. Given the remarkable technological
innovation of past few year and it is
expected that the marketing expectation
and the public requirement will increase and
the cost of the white LED will decrease . In the
other hand the range of uses of LED will
increase within the context of saving energy
and the need for thinner designs .