The LED emits more light per watt than other lighting such as incandescent bulbs. Its efficiency is not affected by the shape and size, unlike light bulbs or fluorescent tubes, but depends on the materials it is manufactured, current that feed, or how it manages heat dissipation.
Typical LEDs are designed to operate with no more than 60 milliwatts [mW] of electric power. Around 1999. Philips Lumileds introduced power LEDs capable of operation in continuous use 1 watt [W]. These LEDs incorporate a piece of semiconductor material much larger than conventional LEDs to match the higher power operation. In addition, the semiconductor material parts are mounted on metal parts to allow heat dissipation. Mentioned efficiency refers only to the LED operating at low temperature in a laboratory. When the temperature is higherand, efficiency is reduced.
The problem is that the efficiency decreases rapidly with increasing power, increasing temperature the intensity of light.
In figure 1 shows a comparison of efficiency between devices such as LED lighting, halogen lights, fluorescent or incandescent bulbs can reach today to about 208 lm/W white LEDs at normal operating temperature.
