LED phosphors have several classified methods under different circumstances. According to applications, phosphors can be divided into phosphors for backlit display, white light lighting, medicine, security, agriculture and agricultural and sideline products, etc. On the basis of energy sources, phosphors can be divided into vacuum ultraviolet phosphors, near ultraviolet phosphors, violet light LED phosphors, blue LED phosphors, etc. In terms of luminescence wavelengths, phosphors can be divided into ultraviolet, blue, green, yellow, red and infrared phosphors, etc. According to raw materials, phosphors can be divided into silicates, phosphate, aluminate, oxide, nitride, fluoride, and sulfide phosphors, etc. Basically, phosphors are involved in every aspect of industry and our life, with differences in performance requirements under various circumstances. Overall, manufacturers and customers of LED phosphors commonly use optical properties (emission light colors, CIE coordinates, light wavelengths), granularity characteristics, and stability (aging performance) to distinguish the merits of the phosphor performance.

As the main source of LED phosphors excitation energy, electromagnetic radiations can be obtained by inert gas discharging, violet light semiconductor chips, blue light semiconductor chips, etc. Excitation energy can be made into light emitting device carrier by a specific process route. Thus, the LED phosphors can be applied on the device and the photoluminescence process can be realized. Take white LED lighting as an instance, LED lamp can be encapsulated by mixing up the red and green phosphors with silica-gel-based materials at a certain proportion and then coating them on gallium nitride LED blue chip. The blue chip emits 450-460 nm blue light when powering up. A part of blue light is absorbed by YAG powder (yellow), Ga – YAG powder (green), SCASN phosphors (such as nitrides 1113) and then the powders emit the corresponding color. Different CCTs (correlated color temperature) and CRIs (color rendering index) of white light illumination can be adjusted by mixing the color of light emitted by phosphors and the transmissive blue light at a certain proportion. Compared with the white LED devices, the processes of the LED phosphors are different for LED backlit display, UV, infrared and other applications. But the luminescent mechanism of these applications is basically the same, which is the excitation energy from a specific light-emitting device being absorbed by the LED phosphors and then being converted to the corresponding wavelengths of light (electromagnetic waves) to meet the lighting requirements. While the above luminous requirements depend on the part of the LED chips, LED powders, LED device packaging technologies and other LED related parts. Among them, the core of luminous performance depends on phosphors, chips and LED packaging technology. So far, the core technique and technology of the chips is still under the control of a few foreign companies. Compared with other factors, the differences of LED chip performance is negligible because of the monopoly of LED chip technology. In practical applications, encapsulation technology and LED phosphors become the determinants of LED device performance. Beijing Nakamura Yuji Technology Co., Ltd and Beijing Yuji Xinguang Photonics Technology Co., Ltd，affiliated with Yuji Group, possess the state-of-the-art technology of LED phosphors and LED packaging respectively, and occupy the leading status of market in their respective fields.