LED light source and the history of the concept

LED (Light Emitting Diode), also LED ceiling light as light-emitting diodes, it is the use of solid semiconductor chip as luminescent materials, when the ends with a positive voltage, the semiconductor carrier in place complex, release excess energy and cause photon emission to produce light .
Application of the principles of semiconductor PN junction made of dimmable LED lights came in the early 1960s, first appeared in 1964, red light-emitting diodes, and then a yellow LED. Until 1994, blue, green LED was developed. 1996, developed a white LED.