直下式LED平板灯的均匀照明设计

Direct-down LED panel light design for uniform illumination

针对超薄LED平板灯导光板价格昂贵以及传统直下式LED平板灯厚度厚和LED数量多等问题,设计了新型直下式LED平板灯。基于边缘光线理论,对光源和目标面进行网格划分并形成映射关系,由Snell公式推导出内外自由曲面的微分方程,采用迭代法计算出内外自由曲面数据,设计实现适用于直下式LED平板灯的大角度二次光学透镜。研究表明:双自由曲面大角度透镜可实现对LED 150°的大角度配光,其照度均匀度为0.86,且能量利用率为99.5%。在不同厚度下,利用大角度二次光学透镜的LED单元阵列距高比(D/H)约等于3时,目标面上的照度均匀度均达到0.88以上。通过对新型直下式LED平板灯照明效果进行模拟,结果完全满足国家建筑照明设计标准,且LED的使用数量为相同功率下传统直下式LED平板灯的30%,减小了20mm的厚度,大大降低了LED平板灯的生产成本。

According to the problems of high price of the ultra-thin LED panel light,high thickness and large quantity of LED for traditional direct-down LED panel light,a new direct-down LED panel light source is designed.The light source and target plane are meshed to form the mapping relationship based on the edge-ray theory.The differential equation of inner and outer freeform-surface is deduced on the basis of Snell formula,and the corresponding data of freeform-surface are calculated by using the iteration method.The secondary optical lens with large view angle for the new direct-down LED panel light is designed.Researches show that the double freeform-surface lens with large view angle can realize large angle light distribution with 1 5 0°,the illumination uniformity is 0.8 6,and the energy utilization is99.5%.When the distance-height ratio（D/H）of LED array for the secondary optical lens with large view angle is approximately equal to 3,the illumination uniformity of the target surface is above 0.88 under different thicknesses.The new direct-down panel light illumination is simulated.The results completely conform to the national building lighting standards.In addition,the number of used LEDs is 30%of that of traditional panel light sources under the same power,and the thickness is reduced by 20 mm,greatly cutting down the production cost of LED flat light.