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荧光粉的吸收散射特性、粒径分布及荧光粉涂层的形状对白光LED色温角空间分布具有直接影响。通过Mie散射理论对不同形状的荧光粉涂层进行了光学计算仿真,研究了荧光粉涂层形状对白光LED空间色温分布的影响规律,以及不同形状的荧光粉涂层效率,并从中找出色温均匀性最佳的荧光粉涂层形状。根据仿真结果,采用具有精确控制喷胶量和喷涂位置功能的高速喷胶技术对1mm2大功率芯片的荧光粉涂层的涂敷工艺进行实验制作,控制器件的平均色温在5 000K,获得荧光粉涂层形状对白光LED色温角空间分布影响的测量结果与计算仿真结果相吻合。通过该方法制作的荧光粉涂层使白光LED的最小色温差异达到537K,远优于目前一般采用的荧光粉涂敷技术。
The absorption and scattering properties of phosphors, the particle size distribution and the shape of the phosphor coating have a direct impact on the color temperature and angular distribution of white LEDs. The Mie scattering theory was used to simulate the different shape of the phosphor coating. The influence of phosphor coating shape on the color temperature distribution of white LED and the coating efficiency of phosphor with different shapes were studied, and the color temperature The best uniformity of phosphor coating shape. According to the simulation result, the coating technology of phosphor coating of 1mm2 high-power chip was experimentally fabricated by the high-speed spray technology with precise control of the amount of sprayed glue and the position of spraying position. The average color temperature of the device was controlled at 5000K to obtain the phosphor The measurement results of the influence of the coating shape on the spatial distribution of the color temperature and temperature of the white LED coincide with the simulation results. The phosphor coating made by the method enables the minimum color temperature difference of the white LED to reach 537K, which is much better than the fluorescent powder coating technology commonly used at present.