Light-emitting diode lights

From CopperWiki

Light-emitting diode (LED) lights are a form of solid-state lighting that uses semiconductor materials. Eco friendly lighting, LEDs are more efficinet, less energy consuming, relatively maintenance free. They are however much more expensive than the regular incandescent lamp or CFL bulb used to light conventional homes.

Researchers in the early 1960s discovered that miniature crystals (gallium arsenide) gave off infrared radiation when electric current was applied. This was the first infrared LED. Then came the first visible spectrum (colored-Red) LED.

Blue LEDs were invented in 1971. White, Green, Blue, UV, Yellow, Amber, and Yellow LEDs went into commercial production in the early 90's. Red LEDs have been used in scientific and indicator devices since the early 70's.

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[edit] All about Light-emitting diode lights

The LED, a semiconductor, generates visible light when an electric current is passed through positive and negative materials. Energy is given off in the form of heat and light. Different colors and greater efficiency are created by altering the composition of the material. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared-emitting diode.

[edit] Where is it being used?

• LEDs are already in use in bicycle lights, mobile phones, camera flashes and Christmas tree lights because they are relatively cheap due to their size and brightness compared to normal bulbs.
• They are also used in street and parking lot lighting, under-counter lighting, and commercial refrigerators.
• They are very popular as lights for illuminating the outside of buildings, allowing for easy color changes.
• Television production studios are installing LED’s to save money and eliminate the need for climbing in the rafters to change bulbs or filters.
• Downlighting and outdoor and track lighting.
• Indicator lights: These can be two-state (i.e., on/off), bar-graph, or alphabetic-numeric readouts.
• LCD panel backlighting: Specialized white LEDs are used in flat-panel computer displays.
• Fiber optic data transmission: Ease of modulation allows wide communications bandwidth with minimal noise, resulting in high speed and accuracy.
• Remote control: Most home-entertainment "remotes" use IREDs to transmit data to the main unit.

[edit] How do they compare with other forms of lightings?

• Typically, a compact fluorescent bulb uses about 20 percent of the energy needed for a standard bulb to create the same amount of light. In early 2009, LED’s used about 15 percent.
• Benefits of LEDs and IREDs, compared with incandescent and fluorescent illuminating devices, include:
  • Low power requirement: Most types can be operated with battery power supplies.
  • High efficiency: Most of the power supplied to an LED or IRED is converted into radiation in the desired form, with minimal heat production.
  • Long life: When properly installed, an LED or IRED can function for decades.
• Unlike incandescent light bulbs, which light up regardless of the electrical polarity, LEDs will only light with positive electrical polarity. LEDs produce more light per watt than do incandescent bulbs, and have an extremely long life span (usually about 50,000 hours
• Conventional LEDs are made from a variety of inorganic semiconductor materials. They don't generate RF wavelengths that cause radio interference, or emit ultraviolet (UV) light -- so LEDs will not readily attract bugs and other insects.

[edit] CopperBytes

In a recent study by The Department of Energy, they’ve estimated that LEDs could reduce national energy consumption for lighting by 29% by 2025. That would save U.S. households $125 billion on their electric bills and would have a significant positive impact on our global warming, energy and emissions initiatives.

[edit] References

• Environmental LED Facts
• It's beginning to look a lot like LEDs
• Light-emitting diode
• LED History / LED Lights
• Fans of L.E.D.’s Say This Bulb’s Time Has Come
• Great bright hope to end battle of the light bulbs The New York Times
• Solid State Steps Out of the Shadows The New York Times

[edit] Source