LED Lamp Research and development

US Department of Energy

In May 2008 the U.S. Department of Energy (DOE) announced details of the Bright Tomorrow Lighting Prize competition. The L Prize is the first government-sponsored technology competition designed to spur lighting manufacturers to develop high quality, high efficiency solid-state lighting products to replace the common light bulb. The competition will award cash prizes, and may also lead to opportunities for federal purchasing agreements, utility programs, and other incentives for winning products. Continue reading “LED Lamp Research and development”

Comparison LED Lamp to other lighting technologies

* Incandescent lamps (light bulbs) create light by running electricity through a resistive filament, thereby heating the filament to a very high temperature so that it glows and produces visible light. A broad range of visible frequencies are naturally produced, yielding a pleasing warm yellow or white color quality. Incandescent light however, is highly inefficient, as approximately 98% of the energy input is emitted as heat.[3] A 100-watt 120 VAC light bulb produces about 1,700 lumens, about 17 lumens per watt. Incandescent lamps are relatively inexpensive to produce. The typical lifespan of an AC incandescent lamp is around 1,000 hours[4] They work well with dimmers. Most existing light fixtures are designed for the size and shape of these traditional bulbs. Continue reading “Comparison LED Lamp to other lighting technologies”

Using LED lamps on household AC power

A single LED is a low-voltage solid state device and cannot be directly operated on household AC current without some circuit to control current flow through the lamp. A series resistor could be used to limit current, but this is inefficient since most of the applied voltage would be wasted on the resistor. A single series string would minimize dropper losses, but one LED failure would extinguish the whole string. Paralleled strings increase reliability. In practice usually 3 strings or more are used. Continue reading “Using LED lamps on household AC power”

LED Lamp Technology overview

General purpose lighting requires white light. LEDs by nature emit light in a very small band of wavelengths, producing strongly colored light. The color is characteristic of the energy bandgap of the semiconductor material used to make the LED. To create white light from LEDs requires either mixing light from red, green, and blue LEDs, or using a phosphor to convert some of the light to other colors. Continue reading “LED Lamp Technology overview”