温度对GaN基LED光学性能的影响

Effect of the Temperature on the Optical Properties of GaN-Based Light-Emitting Diodes

摘要：选择两个不同厂家生产的1WGaN基LED芯片分为两组，一组为未经处理的蓝光芯片，另一组实验样品为涂敷相同荧光粉的白光芯片，两组实验样品均使用透明硅胶封装。对LED进行5～75℃范围内变温光学特性测试，设置的测试电流是350mA。测试结果表明：随着温度升高，蓝光LED主波长不受温度影响，白光LED的相关色温升高；蓝光LED光通量在一定温度范围内先小幅度升高，再小幅下降，而白光LED光通量呈单调下降趋势；蓝光和白光LED的峰值波长均发生红移，发光效率降低，并分析了温度影响LED光学性能的物理机理。

Two kinds of 1 W GaN-based LED chips from different manufacturers were chosen and tested in two groups. One group was blue LED chips, the other was white LED chips coated with fluorescent powder. The two groups were encapsulated with the same transparent silicone. The optical properties of the LED were tested from 5 ℃ to 75 ℃ variable temperature, the test current is 350 mA. The test results indicate that the main wavelength of the blue LEDs is independent from the temperature, while the white LED color temperature increases with the increase of the environment temperature. On the other hand, the luminous flux of the blue LEDs first rises slightly, then decreases with a small amplitude in the certain temperature range, but the one of the white LED drops monotonically. Moreover, the peak wavelengths of blue light and white light LED are red-shifted and the optical efficiency is decreased with the increase of the environment temperature. Based on this, the physical mechanism of the effect of the temperature on the optical properties of LED was analyzed.