文档介绍：LED Modern Applications and Future Advancements
Timothy Delf
Jason Brownlee
February 18, 2005
ECE 3611
Dr. Stanley G. Burns
Focus of Report
LED Background
Structure and Concepts Regarding LEDs
Future Advancements & New Technology
OLED
White LEDs
Problems Facing LED Advancements
Background
Available in multiple wavelengths & colors
Long life at 100,000 hours LED's are the light source with the longest life currently available in the world.
LED's operate as 12 and 24-volt DC systems
High luminescence efficiency
Based on the general properties of a simple twin-element semiconductor diode
LEDs don’t emit ultraviolet light, which degrades ponents, and they emit minimal infrared light, the ponent of heat
Background (Cont.)
Extremely quick refresh rate
Exceptionally wide color palette
Potential for mind-boggling efficiency
Numerous Applications (cell phones, signs, stereos, etc.)
Colors Available
Red
Amber
Yellow
Green
Blue
White
Structure and Concepts Regarding LEDs
Heart of a light emitting diode is a semiconductor chip.
The diode semiconductor contains several very thin layers of material that are sequentially deposited onto a supporting substrate.
Diode chip is mounted in a reflector cup connected to a lead frame, and is bonded to the anode and cathode terminals of the frame through miniature bonding wires.
Entire assembly is then encased in a solid epoxy dome lens
Structure and Concepts Regarding LEDs
A prises a N-type material bonded to P-type material, with electrodes on each end.
Connecting the N-type side of the diode to the negative end of a circuit and the P-type side to the positive end eliminates depletion zone.
Free electrons moving across a diode can fall into empty holes from the P-type layer.
Creates Photons - basic units of light.
All diodes can produce “light”
Most just don’t produce visible light
Wavelength of the photon must be between 400 nm and 750 nm
Even if a diode does produce visible light it must also meet these requirements t