How%20to%20Color%20LEDs

1
How to Color LEDs
LEDColor Standard Brightness Standard Brightness Standard Brightness Standard Brightness High Brightness High Brightness High Brightness High Brightness
LEDColor ChipMaterial lpk(NM) Iv(mcd) ViewingAngle ChipMaterial lpk(NM) Iv3(mcd) ViewingAngle
Red GaAsP/GaP 635 120 35 AS AlInGaP 635 900 30
Orange GaAsP/Gap 605 90 30 AS AlInGaP 609 1,300 30
Amber GaAsP/Gap 583 100 35 AS AlInGaP 592 1,300 30
Yellow Gap 570 160 30 -- -- -- --
Green Gap 565 140 24 GaN 520 1,200 45
Turquoise -- -- -- -- GaN 495 2,000 30
Blue -- -- -- -- GaN 465 325 45
Slide By Adam Bull
2
How to Color LEDs

• The approach is based on encapsulating
  semiconductor
• quantum dots and engineering their surfaces
• Doing so will effectively emit visible light when
  excited by near-ultraviolet
• light emitting diodes (LEDs).

Slide By Adam Bull
3
How to Color LEDs

• The quantum dots strongly absorb light in the
  near UV
• range and re-emit visible light that has its
  color
• determined by both their size and surface
  chemistry.

Slide By Adam Bull
4
How to Color LEDs

• The discretized nature of quantum dot bands means
  that
• the energy separation between the valence and
  conduction
• bands (the band gap) can be altered with the
  addition or the
• subtraction of just one atom, making for a size
  dependent
• Band gap.
• Predetermining the size of the QLEDs dots would
• fix the emitted photon wavelength at the
  appropriate
• specified color, even if it is not naturally
  occurring,
• an ability limited only to dots.
• The extremely small size and versatility of form
  for quantum
• dots allows them to be inserted into any medium
  necessary,
• paint, water, plastics and more.

Slide By Adam Bull
5
General Applications of LEDs

• Architectural Lighting
• Used for Exterior and Interior Lighting
• The GardenLED Series by LEDtronics Only Requires
  Only 12-Volts DC to Operate

• Traffic Lights
• Currently Being Installed in California

• Remote Controls
• Infrared LEDs

• Sources
• LED Uses 12 Watts of Power By Loretta Conley
  lthttp//www.ledtronics.com/product_news/mae_articl
  e_020005.htmgt
• California 'Green Lights' Energy Savings With
  New Traffic Signals By Rob Schlichting
  lthttp//www.energy.ca.gov/releases/2002_releases/2
  002-03-14_led_signals.htmlgt
• Mills, Evan (2005). "The Specter of Fuel-Based
  Lighting". Science 308 1263-1264.
  lthttp//en.wikipedia.org/wiki/LEDBlue_and_white_L
  EDsgt

Slide By Joe Iannucci
6
General Applications of LEDs

• Christmas Lights
• Use About 1/10 of the Electrical Current Used By
  Incandescent Lights

• Dot Matrix Arrangements
• Used for Message Displays

• Sources
• What are LED Christmas Lights? By Bryan
  Pedersen lthttp//www.wisegeek.com/what-are-led-chr
  istmas-lights.htmgt
• Mills, Evan (2005). "The Specter of Fuel-Based
  Lighting". Science 308 1263-1264.
  lthttp//en.wikipedia.org/wiki/LEDBlue_and_white_L
  EDsgt

Slide By Joe Iannucci
7
Applications of LEDs with Quantum Dots

• Screens and Displays
• Still in Development
• Quantum dot-Organic Light-Emitting Devices
  (QD-OLED) Will Replace Liquid Crystal Displays
  (LCD)
• Unlike LCDs, Quantum Dots Generate Their Own
  Light and Can be Tuned to Emit Any Color
• Displays Thin and Very Bright

• Sources
• Quantum-Dot LED May Be the Future of Screens lt

Slide By Joe Iannucci
8
Applications of LEDs with Quantum Dots

• White Light LEDs
• Used to Emit White Light in Laptops, Car
  Interiors, Building Interiors, and Flashlights

• Sources
• Mighty Small Dots lthttp//www.llnl.gov/str/Lee.h
  tmlgt

Slide By Joe Iannucci
9
White Light LEDs

• Researchers at Vanderbilt University Have
  Recently Created a True White Light LED
• Before This Development, White LEDs Had a Blue
  Tint

• How Does It Work?
• Extremely Small Quantum Dots Coat a Blue LED
• Quantum Dots Glow White in Response to the Blue
  Light
• Creates Light Similar to That Created by Common
  Incandescent Bulbs

• Sources
• Quantum Dots That Produce White Light Could Be
  the Light Bults Successor By David F. Salisbury
  lthttp//www.physorg.com/news7421.htmlgt
• Mills, Evan (2005). "The Specter of Fuel-Based
  Lighting". Science 308 1263-1264.
  lthttp//en.wikipedia.org/wiki/LEDBlue_and_white_L
  EDsgt

Slide By Joe Iannucci
10
Advantages of LEDs

• Can emit light of an intended color without the
  use of a filter.
• Design of the package allows light to be focused.
• Insensitive to vibration/shock.
• Hard to break.
• Long life span and give off less heat.

Slide By Ryan McCombs
11
Disadvantages of LEDs

• Currently more expensive than traditional
  lighting.
• Performance largely depends on the ambient
  temperature of the operating environment.

Slide By Ryan McCombs
12
Why use Quantum Dot LEDs?

• Can be tuned to emit at any visible or infrared
  wavelength (color).
• Can be fabricated into a great variety of forms
  and media.
• Allows for incredible flexibility of form,
  letting quantum dots operate in matrixes, sheets,
  films, water solutions, gels, inks, and
  three-dimensional arrays.

Slide By Ryan McCombs
13
Advantages over Organic Light Emitting Diodes

• Retain high quantum yields.
• Retain luminosities over long lifetimes.
• OLEDs have poor photostability and a short
  lifetime.

Tiny quantum dots in a glass tube produce white
light when stimulated by an ultraviolet laser
beam. www.livescience.com
Slide By Ryan McCombs
14
Other Advantages of QLEDs

• The Department of Energy has estimated that LED
  lighting could reduce U.S. energy consumption for
  lighting by 29 percent by 2025, saving the
  nation's households about 125 million in the
  process.
• Infrared radiation in light bulbs produces large
  amounts of heat which accounts for low energy
  efficiency

Slide By Ryan McCombs