Self heating principle of LED light source cob phosphor

When the LED blue light shines on the luminescent material (phosphor), part of it is reflected, scattered and transmitted, and the rest is absorbed. Some of the absorbed light is used as luminescence transition, emitting photons, and some are used as lattice vibration to produce quenching. Luminescence and quenching are two independent and competitive processes in luminescent materials. When quenching is dominant, luminescence is weak and efficiency is low, and vice versa. The fluorescence quantum efficiency is the ratio of the number of photons emitting secondary radiation fluorescence to the number of primary radiation photons absorbing excitation light per unit time.

As shown in the figure, taking the yellow powder of a company as an example, assuming that the blue light power of LED is 4W, the actual white light power is 1.38w after the absorption efficiency of phosphor (74%), internal quantum efficiency (79%) and external quantum efficiency (59%), and it can be concluded that the actual conversion efficiency of phosphor is 34.5%, and others are converted into heat or re converted by other phosphor particles.