以LED为扩展光源,提出一种基于照度分布分割与反馈的方法为LED设计非常紧凑的光学自由曲面透镜,进而设计实现了大距高比(DHR)的直下式背光源。与子光学面联接构成光学面的过程相对应,总照度分布被分割为子照度分布。通过修正子光学面来调整子照度分布,使得总照度分布足够接近于目标照度分布,所需光学面就被构建出来了。该设计过程不依赖于仿真,简便易行,适用广泛。作为实例,一个非常紧凑(透镜的中心高度与LED尺寸相等)的自由曲面透镜被设计出来,作为直下式背光源的配光透镜。仿真结果表明,背光源照度分布的均匀度达到了0.91,相对标准差(RSD)低至0.020 2,总的光能利用率达到了85.5%。 LED as an extension of the light source, based on the distribution of illumination and feedback method for the LED design is very compact optical free-form surface lens, and then designed to achieve a large distance-to-height ratio (DHR) direct type backlight. Corresponding to the process of forming the optical surface by the sub-optical surfaces, the total illuminance distribution is divided into sub-illuminance distributions. By adjusting the sub-optical surface to adjust the sub-illumination distribution, so that the total illumination distribution close enough to the target illumination distribution, the required optical surface is constructed. The design process does not depend on the simulation, simple and easy to use, widely used. As an example, a very compact free-form lens (center height of the lens equals the size of the LED) is designed as a light distribution lens for a direct backlight. The simulation results show that the illuminance distribution uniformity of the backlight reaches 0.91, the relative standard deviation (RSD) is as low as 0.020 2, and the total light energy utilization rate reaches 85.5%.