How to achieve white light of LED lamp beads?
There are three paths for LED to emit white light: 1) blue LED chip + yellow phosphor; 2) purple LED chip + red + green + blue phosphor; 3) blue LED chip + green LED chip + red LED chip. Among the three ways of Baiguang, industrialization has been achieved. The most economical and practical approach is to coat the blue LED chip with yellow phosphor, and the light efficiency of the WLED using this approach is as high as 250lm/W. The market competition of lighting products is becoming more and more fierce and the heat dissipation environment of lighting lamps is getting worse and worse. LED light sources must have better thermal characteristics to meet market needs. The thermal characteristics of the LED light source usually adopt the light output heat and cold ratio. WLED's light output heat and cold ratio, that is, the ratio of the photoelectric parameters of the LED light source at high temperature to the photoelectric parameters at room temperature. This indicator can verify the thermal stability of the LED light source. Phosphors play a vital role in the realization of white light. The phosphor is an inorganic luminescent material with an orderly arranged crystal structure. The stability of its performance is related to the following factors: material system, dispersion coefficient, powder-to-glue compatibility, powder morphology and other four major characteristics. The influencing factors of the WLED light output heat and cold ratio are related to the WLED device materials, and the fluorescent material is the key material. There is no report on the influence of the physical properties of phosphors on the ratio of light output of WLEDs. It is also very important to solve the problem of the thermal characteristics of the LED light source. It is of practical significance to explore the relationship between the physical properties of phosphors and the ratio of light output of WLEDs. .
