Blue LED

The first blue LEDs that can achieve commercial information using gallium nitride substrates which was invented by Shuji Nakamura in 1993 during a career at Nichia Corporation in Japan.
LED was then popular in the late 90's.

Blue LED can be combined into the red and green LEDs that have been there before to create white light.

With white LED light is now the majority are made by coating a substrate of gallium nitride (GaN) with yellow phosphorus.
Because the color yellow stimulates the red and green color receivers in the human eye, the combination of yellow and blue phosphors of the substrate will give the impression of a white color for the human eye.

White LEDs can also be made by coating the phosphor blue, red and green in the substrate near ultraviolet is more or less similar to the way fluorescent lamps work.

Current methods for creating white light from LEDs is to not use phosphorus at all but uses a zinc selenide substrate which can emit blue light from the active area and the yellow light from the substrate itself.