|
Picture Lights
A light-emitting diode (LED) is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction. This effect is a form of electroluminescence. more...
 Home
Bedding
Furniture
Home Decor
Miscellaneous
 Bath
Lamps, Lighting, Ceiling...
 Bathroom Lighting
Ceiling Fans
Ceiling Fixtures
Chandeliers
 More than 22'' Wide
Up to 22'' Wide
Children's Lighting
Desk Lamps
Exterior, Landscape Lighting
Lamp Posts
Light Fixtures
Other
Path Lighting
Spot Lights, Flood Lights
Floor Lamps
Lava Lamps, Party Lights
Lighting Accessories
Ceiling Fan Pulls
Lamp Finials
Lamp Shades
Light Bulbs
Lighting Remotes, Controls
Other Accessories
Multiple Lamp Sets
Neon Signs
Night Lights
Other Lamps, Lighting
Paper Lanterns
Pendant Lighting
Picture Lights
Recessed Lighting
Sconces, Wall Lamps
String Lights
Table Lamps
Asian, Oriental
Country, Americana
Mission, Arts & Crafts
Nautical
Other
Retro
Tiffany, Stained Glass
Tropical
Victorian
Western
Track Lighting
Under Cabinet Lighting
Pools & Spas
Window Treatments
Patio & Grilling
An LED is usually a small area source, often with extra optics added to the chip that shapes its radiation pattern. The color of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible, or near-ultraviolet. An LED can be used as a regular household light source.
History
In the early 20th century, Henry Round of Marconi Labs first noted that a semiconductor junction would produce light. Russian Oleg Vladimirovich Losev independently created the first LED in the mid 1920s; his research, though distributed in Russian, German and British scientific journals, was ignored. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955. Experimenters at Texas Instruments, Bob Biard and Gary Pittman, found in 1961 that gallium arsenide gave off infrared radiation when electric current was applied. Biard and Pittman were able to establish the priority of their work and received the patent for the infrared light-emitting diode. Nick Holonyak Jr., then of the General Electric Company and later with the University of Illinois at Urbana-Champaign, developed the first practical visible-spectrum LED in 1962 and is seen as the "father of the light-emitting diode". Holonyak's former graduate student, M. George Craford, invented in 1972 the first yellow LED and 10x brighter red and red-orange LEDs.
Shuji Nakamura of Nichia of Japan demonstrated the first high-brightness blue LED based on InGaN, borrowing on critical developments in GaN nucleation on sapphire substrates and the demonstration of p-type doping of GaN which were developed by I. Akasaki and H. Amano in Nagoya. The existence of the blue LED led quickly to the first white LED, which employed a Y3Al5O12:Ce, or "YAG", phosphor coating to mix yellow (down-converted) light with blue to produce light that appears white. Nakamura was awarded the 2006 Millennium Technology Prize for his invention.
LED technology
Physical function
Like a normal diode, an LED consists of a chip of semiconducting material impregnated, or doped, with impurities to create a p-n junction. As in other diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction. Charge-carriers—electrons and holes—flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.
Read more at Wikipedia.org
|
|
Contact
