A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated.When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.
An LED is often small in area (less than 1 mm2) and integrated optical components may be used to shape its radiation pattern.

Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared light. Infrared LEDs are still frequently used as transmitting elements in remote-control circuits, such as those in remote controls for a wide variety of consumer electronics. The first visible-light LEDs were also of low intensity, and limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.
Early LEDs were often used as indicator lamps for electronic devices, replacing small incandescent bulbs. They were soon packaged into numeric readouts in the form of seven-segment displays, and were commonly seen in digital clocks.

Recent developments in LEDs permit them to be used in environmental and task lighting. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, and faster switching. Light-emitting diodes are now used in applications as diverse as marine lighting, aviation lighting, automotive headlamps, advertising, general lighting, traffic signals, camera flashes and even LED wallpaper.

One of the benefits of the LED is its long lifetime. Because they have no movable parts or filaments that may break, LED’s can have long lifetime. 

We normally define the lifetime of a LED as the time expected for it to drop to 70 % of its initial light output. A typical lifetime is 50.000 hours. But this is heavily dependant on the temperature inside the diode itself. At high temperatures, the blue chip and phosphor layer degenerates and the LED will eventually lose light.

• Energy saving: 80% compared to incandescent lights. 75% compared to halogen lights. 50% compared to compact fluorescent lights.
• Average life span: 
LED lights over 50.000 hours.  Incandescent lights 1.000 hours. Halogen lights 2000 hours. Compact fluorescent lights 6000 hours.
• Eco-compatibility: LED lights are built without the use of dangerous raw materials.
• They do not contain mercury, chrome lead or xenon and they are compliant to RoHS European regulations regarding use of polluting materials.
• Low heat generation.
• No emission of UV rays.
• No emission of IR rays.
• Ample spectrum of color temperature (°K)
• No electromagnetic emission.
• Higher performance compared to traditional systems.
• Bump resistant.
• Reliability in temperature variations.