波前编码系统相位板视场效应的消除

Elimination of Field Effect of Wavefront Coding System

通过在光学系统的光阑面上加入一个非球面相位板,使得光学系统的成像对离焦不敏感·但当入射视场角较大时,图像的边缘发生变形且难以恢复·针对此问题,提出了两种解决方案,方案一是把相位板移至光路中光线较为平缓的区域,但不是系统的光阑位置;方案二是保持相位板位置不变,优化整个光学系统,使相位板前的光线能够平缓地入射到相位板·实验中对一个EFL=12.5mm,F/#=1.3,半视场角为13.5°的波前编码实际系统进行仿真比较,得出方案二可以有效地消除波前编码相位板引入的视场效应·

Wavefront coding technology could make the optical system insensible to the defocus by adding an aspherical phase mask in the pupil plane of the optical system. But when the incident angle gets larger, the edges of the image become distorted and hard to be restored. To sovle this problem, two methods are proposed. One is to move the phase mask to the plane where the ray gently incident on the phase mask, but it is not the pupil plane. Another is to optimize the whole optical system to make the ray gently incident on the phase mask on the pupil plane. The parameters of the system are： EFL=12.5 mm, F/# = 1.3, the maximal 1/2 filed angle is 13.5°. The simulation results show that the second method is very effective to eliminate the effect which is caused by the large field.