LED technology has advanced significantly. LEDs are now commonly used for lighting applications due to their energy efficiency and long lifespan. LEDs operate by passing electricity through crystalline solids unlike conventional lighting methods. Early LEDs could only produce red light but advances in materials allow different colors to be produced. White LEDs use a blue LED combined with yellow phosphor. Manufacturing LEDs is a complex process involving growing semiconductor wafers, dicing dies, packaging, and testing. Proper heat management is important for LED lifespan and performance. LEDs have many applications from indoor lighting to automotive due to their controllability and flexibility. Further advances may allow multi-color chips and integrated circuits on LEDs.

1. PREPARED BY: UNDER THE SUPERVISION OF:
DEPARTMENT OF ELECTRICAL ENGINEERING
ER. ABHINAB KUMAR
(ASSISTANT PROFESSOR)
RAHUL KUMAR
BACHELOR OF TECHNOLOGY
ELECTRICAL ENGINEERING
(3RD YEAR)
ROLL NO:1473420034
A
PRESENTATION ON
LED TECHNOLOGY
RAJKIYA ENGINEERING COLLEGE BANDA

2. •ABOUT SSL
•INTRODUCTION
•CURRENT TECHNOLOGY
•CONSTRUCTION
•HEAT ISSUES
•LED COLOUR
•PHOSPHOR TECHNOLOGY
•SPECTRAL DISTRIBUTION OF
WHITE LIGHT
•LED MANUFACTURING STAGES
•LEAD USEFUL CHARACTERICTICS
•LEAD SYSTEM DESIGN
•APPLICATIONS
•CONTROLLABILITY
•THE FUTURE
•DISADVANTAGES
•CONCLUSION

3. What is Solid State Lighting
•Heating up bits of wire
Conventional Methods of converting electrical energy to light
•Passing Electricity through gas at near vacuum
•Passing Electricity through gas above atmospheric pressure

4. How About LED’s
•Passing Electricity through small amounts of crystalline solids
•Solid State device
Works well with other semiconductors
•Initially used for panel indicators
•Discovered in 1962 by Nick Holonyak
•In 1963 he predicted white LEDS with 10X efficiency of
Incandescent

5. Early LED colour
•Initially red mass produced from 1969
•GaAsP Gallium Arsenide Technology
produced red, amber and yellow early
green produced by IR and phosphor
•GaAIA Gallium Aluminum Arsenide High
brightness red LEDs from 1984
•InGaN Indium Gallium Nitride Technology
produced blue and green
•Allowed development of White LED

6. Current Technology
•Based on InGaN and A AnGaP
•Many colours possible
•Colour varies with growth
temperature of active layer
•Efficiency drops in Green
•Different compositions behave
differently
•Reds and ambers have shorter life
and greater colour shifts
Blues more stable

7. Construction of LEDs
•Standard 5mm LED
•Epoxy body sometimes coloured
•Leads identified for polarity
•Reflector maximises light output
•Die, semiconductor that emits light

8. Construction of LEDs
•High output LEDs
•Large die with reflector
•Mounted to Slug heat sink
•Leads exit to side clear of light path
•Moulded lens gathers and directs light
•Various distribution patterns
•Many different packages

9. LED Colour
•Each type of LED emits light
in a narrow band width
•Good for saturated colour
•Limited for RGB mixed white

10. White LEDs
•Fluorescence; uses blue die with phosphor
•Combination of Blue from die and Yellow from
phosphor gives
visual white
Colour not even across LED
Warmer colours less efficient

11. Phosphor technology
•Best is Itrium Aluminium Garnate Cerium
•Produces broad spectrum yellow
•90% efficient converting blue to yellow
•Deficient in Red
•Strontium Sulphide Europium
•Produces increased red
•Much less efficient
•Can create pink tinge in 2700K range
•Importance of even thickness Consistent
colour
•Match binning of phosphor with LED
•Recent development of phosphor wafers or
better control of thickness

12. Spectral Distribution of White

13. White Light LEDs
•Research goal to create white light
directly from die
•ZnSe (Zinc Selenide) is a candidate
technology not high output
•Development as Zinc Oxide
nanostructure semiconductor RGB

14. LED Manufacturing Stages
•Reasons for product variation
•The Wafer
•The Die
•The Package

15. The Wafer
•Disk of the crystalline material that forms
semiconductor
•Grown on mineral substrate: Epitaxy
Saphire, Silicone Carbide 2” or 6”
diameter
Aim to use 12” Silicone for economy
•Tightly controlled conditions to achieve
uniform result
•First layer grown at 1000°C
•Second at 700°C
•Final at 1000° C
•Risk of changes to middle layer
Substrates flex
•Varies thickness of layers
•Process takes 5 to 6 hours

16. The Die
•Wafer literally “diced” like
carrots!
•Dies “binned”
•For colour (chromaticy)
•For forward voltage
•For output

17. Packaging
•Connections made to die
•Die inserted in package
•Many dies in same package
•Device tested for:
forward voltage
colour (chromacity)
lumen output
LEDs then Binned

18. Binning
•Much discussed aspect of LEDs
•At end of production line
measurements made
fraction of a second
device at room temperature 25°C
fully automated process
First stage of quality control
•Possibly the most important
aspects tested:
Colour
Lumen Output
Forward Voltage

19. Heat Issues
•Temperature in die
 determines LED survival
 determines operating life
 determines light output
 determines efficiency
•Higher the temperature
lower light output
lower the efficiency
•Critical temperature much lower than
conventional lamps
•LED internal temperatures 100°C to
150°C absolute maximum depends on
chip

20. LEDs‐ Useful Characteristics
• Electrically Efficient
• Long Lifetime
• Low radiated heat
• Emit pure colors without filters (more
efficient)
• Intensity can be varied over operational
range with little
spectral shift
• Rapid on/off capability
• Small size allows unprecedented
flexibility in application
• Rugged
– Solid state
– Not damaged by repeated on/off cycles
– No fragile glass envelope
• No hazardous materials (e.g. mercury)

21. LEDs‐ Useful Characteristics
‐Can Match Spectrum to Application

22. LEDs‐ Useful Characteristics
•Highly flexible Advanced
Lighting Control Systems
HELIAC adaptive lighting system

23. LED System Design
“Standard” 5mm
Standard surface‐mount (SMT)
High‐power emitter types
Pre‐packaged high‐power
arrays

24. LED System Design
Optics
– Commercially available
– Custom / application specific
•Diffusers
•Lens
•Collimators
•Remote Phosphor

25. LED Mechanical Components &
Configuration
Power and signal
distribution
Arrays of LEDs
(actively or passively
cooled
Optics and protection
mechanisms
Control box
(many configurations
possible)

26. APPLICATIONS
•LED Plant Lighting in Space
•System Configuration; Overhead Bars
•Large Sole Source Lighting Arrays
•IN DOMESTIC USES
•IN AUTOMOBILES
•FOR INDICATION

27. LED Plant Lighting in Space
Astroculture‐4
1994
First LED plant
lighting in
space
Veggie‐01
2014

28. System Configuration; Overhead Bars

29. Large Sole Source Lighting Arrays

30. Controllability
•LEDs easy to control - they are
an electronic component!
•Facades of light easy to do
Imagery allows architecture to
change day and night
•Reactive and interactive
surfaces, walls and ceilings
•LEDs deliver colour easily and
efficiently compared with
other light sources

31. The Future
•Field of light products much more likely to be
successful
•optimizes use of LED and existing backlight
technology
•opens possibilities for fittings not to be
rectangular or circular
•no longer are fitting sizes restricted by set
dimensions of lamps
•First product recall, High efficiency LEDs
recalled from fittings manufacturers
•Production halted for 4 months
•Line voltage LEDs
•Seol semiconductor Acriche
2W & 4W 120V and 230V warm and cool white
30LmW to 40 LmW headline efficacy
•No transformer losses
•Simplified Wiring

32. The Future
•Multi colour chips on same
wafer - White by color mixing
Complex circuits on chip -
•Zinc Oxide Nanotechnology
Semiconductor
•LED materials can also
produce energy from light
•LED detectors / emitters
•Development of
Photovoltaics using InGaN
junctions

33. Environmental Issues
•Price per lumen of LED exceeds all other
light sources
•Revenues consumed by continuous
development
•Additional cost must be argued on basis
of:-
low maintenance
low energy in use
System has finite life
Not always determined before
installation
•Whole system will require replacement
at end of life
•- Issues with WEEE for disposal and re-
cycling

34. • LEDs are currently more expensive, price per lumen,
on an initial capital cost basis, than more conventional
lighting technologies.
• LED performance largely depends on the
ambient temperature of the operating
environment. Over-driving the LED in high
ambient temperatures may result in
overheating of the LED package, eventually
leading to device failure. Adequate
heat-sinking is required to maintain long life
• LEDs must be supplied with the correct
current. This can involve series resistors
or current-regulated power supplies

35. Conclusion
•LEDs increasingly common in lighting
applications
•They remain the most complex light-
source to design and
specify
•Manufacturers are guardians of
knowledge
•Big players potential to monopolize
design to installation
•Professional Lighting Design community
must learn more
•Personal research and demanding
information from suppliers
•Professionals must determine the
suitable light-source for every
application
•LEDs will never be the universal light-
source for all applications

36. Thank you

37. QUERIES?