为了弱化或消除LED失效对均匀性的影响, 提出了一种基于复眼透镜的匀化光斑整体累加方案.该方案先对单颗LED进行匀化设计, 再通过LED位置误差研究推广至LED阵列, 实现每颗LED在曝光面上均能产生相同大小的匀化光斑.然后利用软件进行仿真, 设计了一款曝光光源, 并搭建了相应实验平台.该光源最大辐照度值为18.2 mW/cm2, 均匀性为86.9%, 完全满足实际曝光指标.在此基础采用遮挡光源的方式模拟不同位置的LED失效, 进行了辐照度均匀性实验.结果表明, 少量LED失效对辐照度均匀性的影响在1%以内, 甚至LED阵列接近一半失效时均匀性仅下降5%.该设计方案可长期维持辐照度均匀性, 更适用于实际生产.

For weakening or eliminating the effect on uniformity, the method of uniform light accumulation based on fly-eye lens was presented. At first, illumination uniformity is designed for one LED. Then the same uniform light spot can be generated on the target surface from every LED, according to the study of LED position error. Next, An exposure light source is designed by a simulation optimization software. The maximum illuminance is 18.2 mW/cm2 while the uniformity is 86.9%, which meeting the exposure requirements fully. At last, an experiment is made to test the illumination uniformity with the method of blocking LEDs. The result shows that a few invalid LEDs cause less than 1% decease of uniformity. Even half of invalid LEDs lead to a result that uniformity declines by less than 5%. Thus, this method better suits actual manufacture than others by maintaining illumination uniformity for a long period.