基于折反耦合的超短焦投影成像系统的设计

Design of Ultrashort-Throw Projection Imaging System Based on Catadioptric Coupling

针对折反式超短焦投影成像光学系统由于结构复杂、投射比小、视场角大造成优化像差时收敛速度慢的问题,提出一种基于折反耦合点的超短焦投影成像光学系统的设计方法。通过对光学系统中折射透镜组与凹面反射镜之间各视场及孔径处光线耦合点位置的计算,将理想耦合点与实际耦合点的偏差作为评价函数来优化像差,同时采用正向设计和反向设计相结合的方式,有效提高光学系统优化效率。利用此方法设计了一个超短焦投影镜头,可在486 mm处投射100 inch(2540 mm)尺寸画面,TV畸变小于0.2%,各视场调制传递函数(MTF)在截止频率为117 lp/mm处均达0.5以上。

The complex structure,small projection ratio,and large field-of-view of the catadioptric ultrashort-throw optical projection imaging system are result in slow convergence speed of optimized aberration.Hence,we proposed a design for an ultrashort-throw optical projection imaging system based on catadioptric coupling point herein.The deviation between the ideal and observed coupling points determined by calculating the position of the light coupling point at an aperture as well as the each field-of-view between the refracting lens set and the concave mirror in the proposed optical system is used as an evaluation function to optimize the aberration.Moreover,the forward and reverse designs are combined to effectively increase the optimization efficiency of the proposed optical system.Using this technique,we designed an ultrashort-throw projection lens that can project a 100 inch(2540 mm)size picture at 486 mm,with TV distortion of less 0.2%and modulation transfer function(MTF)of each field-of-view of more 0.5 at 117-lp/mm cutoff frequency.