Blue LED chip coated with (YAG) yellow phosphor that can be excited by blue light

A yellow phosphor (YAG) yellow phosphor is applied to the blue LED chip, and the blue light emitted by the chip complements the yellow light emitted by the phosphor to form white light.
This technology is monopolized by Nichia Corporation of Japan, and a principle disadvantage of this scheme is that the emission spectrum of Ce3+ ions in the phosphor does not have continuous spectral characteristics, and the color rendering property is poor, which is difficult to meet the requirements of low color temperature illumination, and luminous efficiency. Not high enough, it needs to be improved by developing new high-efficiency phosphors.