Basic principle of a LED (light emitting diode)
A light emitting diode consists of multiple layers of semi-conducting material. When the diode is being used with direct current, light is produced in the active layer. The light produced is decoupled directly or by reflections. In contrast to incandescent reflector lamps, which emit a continuous spectrum, an LED emits light in a particular color. The light’s color depends on the semiconductor material used. Two material systems are mainly used, in order to produce LEDs with a high degree of brightness in all colors from blue to red and, by means of luminescence conversion, also in white. Different voltages are necessary, to operate the diode.
Advantages of LED technology
1. Energy efficient – LED’s are now capable of outputting 135 lumens/watt.
2. Long Lifetime – 50,000 hours or more if properly engineered.
3. Rugged – LED’s are also called “Solid State Lighting (SSL) as they are made of solid material with no filament or tube or bulb to break.
4. No warm-up period – LED’s light instantly – in nanoseconds.
5. Not affected by cold temperatures – LED’s “like” low temperatures and will startup even in subzero weather.
6. Directional – With LED’s you can direct the light where you want it, thus no light is wasted.
7. Excellent Color Rendering – LED%.