What are the types of LED light sources

        There are several types of light sources:
　　1. Two primary color phosphor conversion white LED light source two primary color white LED is made of blue LED chip and YAG phosphor. The commonly used Blu ray chip is InGaN chip. In addition, a1ingan chip can also be used. The advantages of the method of blue chip LED with YAG phosphor are: simple structure, low cost, relatively simple manufacturing process, and YAG phosphor has been used in fluorescent lamps for many years, and the process is relatively mature. Its disadvantage is that the efficiency of blue LED is not high enough, which makes the efficiency of LED low; The phosphor itself has energy loss; Phosphors and packaging materials age with time, resulting in color temperature drift and shortened service life.
　　2. Three primary color phosphor converted white LED light source can effectively improve the color rendering of LED on the premise of high efficiency. The common way to obtain three primary color white LEDs is to use ultraviolet led to excite a group of three primary color phosphors that can be effectively radiated. This type of white LED has high color rendering, light color and color temperature can be adjusted, and the light efficiency of LED can be improved by using fluorescent powder with high conversion efficiency. However, there are still some defects in the method of UV LED + three primary color phosphor, such as the low aging rate of phosphor in converting UV radiation; Powder mixing is difficult; Packaging materials are easy to age under UV irradiation and have short service life.
　　3. The multi chip white LED light source encapsulates the red, green and blue LED chips together, and mixes the light they emit together to get white light. This type of white LED light source is called multi chip white LED light source. Compared with phosphor conversion white LED, the advantage of this type of LED is to avoid the energy loss of phosphor in the process of light conversion and obtain higher light efficiency; Moreover, the light intensity of LEDs with different light colors can be controlled separately to achieve the effect of full-color color change, and better color rendering can be obtained through the selection of LED wavelength and intensity. The disadvantage of this method is that the semiconductor materials of LED chips with different light colors are very different, the quantum efficiency is different, the light color is inconsistent with the change of driving current and temperature, and the attenuation speed with time is also different. In order to maintain the stability of color, it is necessary to add feedback circuits to compensate and adjust the LEDs of three colors, which makes the circuit too complex. In addition, heat dissipation is also the main problem perplexing the multi-chip white LED light source.