The principle of blue LED+YAG phosphor is to coat a layer of YAG phosphor on a blue chip with a wavelength of 460nm, excite the phosphor with a blue LED to generate yellow light with a wavelength of 555nm complementary to blue light, and mix the complementary yellow light with blue light to obtain white light. It is unrealistic to make a breakthrough in chip manufacturing/epitaxial materials in a short time. The industry generally believes that new phosphor materials are an effective way to break through the international patent barrier of white LED. For example, OSRAM's TAG aluminate yellow phosphor is a successful case of breaking through the patent of YAG phosphor (other main phosphor technologies used to realize white LED include Toyota Synthetic, Intemet and Tridonic silicate series phosphors, etc.). ). At present, almost all yellow powders on the domestic market are YAG aluminate phosphors patented in Japan and Asia. Therefore, in order to take the initiative in the white LED market, China needs its own white LED phosphor technology. Dr. Wang of Yuji Xinguang Co., Ltd. said that nitride yellow phosphor is expected to replace YAG aluminate phosphor to avoid patent barriers related to Japanese chemistry.