基于定抛物面调制的直下式匀光照明透镜设计

对于近场大角度的匀光照明系统，透镜的一般设计方法是采用内表面为球形的自由曲面透镜设计,计算的自由曲面透镜只需考虑一次折射。但是当角度达到一定范围时，在透镜的内表面容易发生全反射，导致目标面照度不均匀。为了在近场照明系统中得到更大角度的配光，提出一种以合适的抛物面作为自由曲面透镜的内表面的设计方法，内抛物面先对光源的能量进行一次扩散，再计算自由曲面面型，通过模拟仿真，实现了在距离光源15 mm处形成半径40 mm的光斑，均匀度达到95%，能量利用率达到97.8%，相对于传统的直下式透镜，提高了照明的均匀度，同时减少了箱体的厚度。

LED direct backlight lens design based on modulation of paraboloid inner surface for uniform illumination

In the system of near-field uniform lighting, lens design methods commonly use sphere as the inner surface, and the calculation of the free-form surface only considers primary reflection . But when the angle reaches a certain scope, total reflection on the free-form surface of the lens is easy to occur ,which will lead to the poor illumination performance. In order to get the larger light distribution in the near-field lighting system ,a free-form lens design method based on the modulation of the parabolic inner surface was proposed. The parabolic can diffuse the energy of the light source, and then calculate the free-form surface. Through simulation, the uniform light spot with 40 mm radius can be realized at 15 mm distance away from light source, while the uniformity reaches 95%, the efficiency reaches 97.8%. Comparing with traditional direct lens, the uniformity is enhanced and the height of backlight box is decreased by using the structure of this lens.