The Influence of Different Phosphor Coating Methods on the Temperature of LED

Abstract

High-power light-emitting diodes (LEDs) with its energy saving, environmental protection, long life and other excellent performance gradually penetrated into modern lighting. In order to study the influence of different phosphor coating methods on the temperature of LED, high-power LED devices with different phosphor coating methods were designed, and the thermodynamic models are established by ANSYS software for simulation, which compares the simulation with the measured results. The main method to realize the white LED is to apply yellow phosphor to the surface of the blue-ray chip, and to get the blue-yellow mixed white light by exciting the yellow phosphor on the surface of the chip. However, in the process of blue light excitation of yellow phosphor, there will be a part of the light convert into thermal energy, due to the low thermal conductivity of the phosphor layer, phosphor is often in a high temperature state, resulting in high-power white LED light decay faster. The experimental prediction result is that the analog temperature is lower than the phosphor thermal load and the measurement temperature, and the amount of phosphors are applied affects the chip junction temperature, aluminum substrate temperature and lens top temperature. It also measures the temperature at the bottom of the aluminum substrate and the top of the lens, the calculated chip temperature is closer to the simulated phosphorus heat load temperature. In this paper, comparing the chip temperature measured by different phosphor coating methods with the simulation data, it is concluded that the temperature of the chip is the highest when the phosphor is directly in contact with the chip.