LED is cold and can work for up to several hundred thousand of hours. Meanwhile, it's small, low voltage, rapid responding, and requires no warming. Light sources with low efficiency and high power consumption are being replaced by LED.

 

Common light sources available on the market include incandescent lamps, fluorescent lights, and HID lamps etc. In recent years, great progress has been achieved on the efficiency and cost of LED. Comparing to the coming incandescent lamps, the LED is power-saving, small, and directive.