波前编码中立方相位板的装配及加工误差对成像性能的影响  

Effect of Assembling and Machining Errors on Wavefront Coding Imaging Performance of Cubic Phase Mask

作　　者：张效栋[1] 张林[1] 刘现磊[1] 姜丽丽[1] 

机构地区：[1]精密测试技术及仪器国家重点实验室(天津大学),天津300072

出　　处：《纳米技术与精密工程》2015年第2期134-140,共7页Nanotechnology and Precision Engineering

基　　金：国家重点基础研究发展计划(863计划)资助项目(2011CB706706);国家自然科学基金资助项目(51175377)

摘　　要：在波前编码技术中,通过立方相位板的光学调制和后续图像处理,扩展了系统景深.其中系统的光学调制过程,可以用广义光瞳函数描述.系统的广义光瞳函数描述了光通过立方相位板后相位的变化过程.立方相位板是波前编码技术的关键器件,装配及加工误差直接影响系统的成像性能.本文通过推导不同误差情况下的广义光曈函数,得到了立方相位板装配及加工误差对点扩散函数(PSF)和调制传递函数(MTF)的变化规律.评估这些规律,得到了装配和加工误差对系统成像性能的变化规律,为装配和加工过程提供了基本的指导.文中分析了不同装配误差和加工误差对于系统性能的影响,其中围绕Z轴的装配误差和加工中振动引起的正弦形状误差对于MTF的影响最大.因此,在装配和加工中应尽量避免围绕Z轴的装配误差和正弦形状误差,正弦形状误差的PV值应保持在0.5μm之内.In wavefront coding,a cubic phase mask extends the field depth of an imaging system through modulation and deconvolution. The modulation could be defined by a pupil function which describes how light wave is affected after passing through the mask. As the key optical element responsible for providing the designated spatially varying path length,the machining and assembling errors（ MAEs） affect the imaging performance directly by deviating the modulation. In this paper,with derivation of the generalized pupil function under various errors,the influence rules of assembly and machining errors of cubic phase mask on imaging performance were obtained. To assess these MAEs,the point spread function（ PSF） and the modulation transfer function（ MTF） were derived. The influence rules of MAEs on imaging performance were established as well. These rules are eventually developed into the necessary and essential guidelines to the machining and assembly process. The MTF value is very sensitive to the alignment accuracy of rotation around Z-axis introduced by misassembling and to the sinusoidal-type figure error introduced by excited vibrations during machining. Therefore,the tilts around Z-axis in assembly process andthe sinusoidal-type figure error in machining process should be avoided,and the PV value of figure error should be within 0. 5 μm.

关 键 词：波前编码 装配偏转 加工误差 面型形状误差 

分 类 号：TH16[机械工程—机械制造及自动化] TG95[金属学及工艺—钳工工艺]