为了与3DLP投影机中分光合光棱镜组实现对接，设计了一种基于3DLP投影机的超长后截距双远心照明光路，工作波段为400~700 nm，放大倍率为1.9倍，物方数值孔径为0.4，像方数值孔径为0.2，后截距达到140 mm，物方远心度和像方远心度都小于1°，采用尺寸为7.6 mm×4.8 mm×62 mm的方棒匀光和0.67 inch的DMD芯片，中继照明系统满足了方棒要与DMD相匹配的要求，并且具有高的照度均匀性和80%的能量利用率。

The 3DLP projector with long interception and double telecentric illumination light path is designed. The operating wavelength of the illumination light path is 400~700 nm. The magnification is 1.9. The object space numerical aperture is 0.4. The image space numerical aperture is 0.2. The backward interception reaches 140 mm. Besides, the telecentric angle of object space and image space are both less than 1°. The square rods with the size of 7.6 mm×4.8 mm×62 mm and 0.67 inch DMD chips are used. The relaying illumination system satisfies the match requirements between DMD and square rods. At the same time, the high illuminance uniformity and 80% utilization rate of the light energy are obtained.