White light led
Any one know that the wavelength range of visible light between 380nm～760nm，human eyes can saw seven kind of color in 380nm～760nm. the seven kind of color is red, yellow ,orange, green, glen , blue and ultraviolet respectively , they are signal color, for example green led lit that wavelength is 565nm. so there are not white light in optical spectrum of visible light. the white light is not signal color light. fox example the blue light and yellow light mix to white light, and mix up the blue light and green light with red light produce white light. the key step of white production is blue light.

Let’s summarize what is important note
*The engineer utilized bright of red green and blue to producing white light, in general the ratio of luminous of red green and blue is 3：6：1.
*The blue light (InGaN) LED to stimulate the yellow phosphor to producing
white light.
*The blue light (InGaN) LED to stimulate the RGB (red,green,blue )phosphor to producing white light