1. Multi-chip white light LED light source, the red, green and blue LED chips are packaged together, and the light emitted by them is mixed together, and white light can also be obtained. This type of white LED light source is called a multi-chip white LED light source. Compared with phosphor-converted white light LEDs, the advantage of this type of LED is that it avoids the energy loss of phosphors in the light conversion process, and can obtain higher light efficiency; Full-color discoloration effect, 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 decay speed with time is also different. In order to maintain the stability of the color, it is necessary to add a feedback circuit for compensation and adjustment to the LEDs of the three colors, which makes the circuit too complicated. In addition, heat dissipation is also a major problem that plagues multi-chip white LED light sources.

2. The conversion of three primary color phosphors can effectively improve the color rendering of LEDs under the premise of higher efficiency. The most common way to obtain three-primary white LEDs is to use ultraviolet LEDs to excite a group of three-primary phosphors that can be effectively radiated. This type of white LED has high color rendering, adjustable light color and color temperature, and the use of phosphors with high conversion efficiency can improve the light efficiency of the LED. However, the method of UV LED + tri-color phosphor still has certain defects, such as the low efficiency of phosphor in converting ultraviolet radiation; the powder mixing is difficult; the packaging material is easy to age under ultraviolet light and has a short lifespan.

3. Two-primary color phosphor conversion, two-primary white LED is made of blue LED chip and YAG phosphor. The commonly used blue light chips are InGaN chips, and AlInGaN chips can also be used. The advantages of the blue chip LED with YAG phosphor method are: simple structure, low cost, relatively simple manufacturing process, and YAG phosphor powder has been used in fluorescent lamps for many years, and the process is relatively mature. The disadvantage is that the efficiency of the blue LED is not high enough, so that the LED efficiency is low; the phosphor itself has energy loss; the phosphor and the encapsulation material age over time, resulting in color temperature drift and shortened life.