As everyone knows, the visible light spectrum has a wavelength range of 380 nm to 760 nm, which is the seven-color light that can be perceived by the human eye - red, orange, yellow, green, cyan, blue, and purple, but the light of each of the seven colors is A monochromatic light.
For example, the peak wavelength of red light emitted by an LED is 565 nm. There is no white light in the spectrum of visible light, because white light is not monochromatic light, but composite light synthesized by a variety of monochromatic lights, just as sunlight is white light synthesized by seven monochromatic lights, while in color televisions White light is also composed of three primary colors red, green, and blue.
Thus, to make the LED emit white light, its spectral characteristics should include the entire visible spectral range. However, it is impossible to manufacture LEDs of this performance under process conditions. According to people's research on visible light, white light that can be seen by human eyes requires at least two kinds of light mixing, that is, two-wavelength light (blue light + yellow light) or three-wavelength light (blue light + green light + red light) mode. . The above two modes of white light require blue light, so the ingestion of blue light has become a key technology for manufacturing white light, that is, the "blue light technology" currently chased by major LED manufacturing companies. There are only a few manufacturers in the world who have mastered "Blu-ray technology", so the promotion and application of white LEDs, especially the promotion of high-brightness white LEDs in China, has a process.