激光投影成像中影响激光散斑抑制的参数分析及实验研究  

Parameter Analysis and Experimental Study of Influence on Laser Speckle Suppression in Laser Projection Imaging

作　　者：黄艳 Huang Yan(Electronic Engineering Department,Zhangzhou Institute of Technology,Zhangzhou 363000,Fujian,China)

机构地区：[1]漳州职业技术学院电子工程学院,福建漳州363000

出　　处：《激光与光电子学进展》2022年第13期107-112,共6页Laser & Optoelectronics Progress

基　　金：福建省中青年教师教育科研项目(JAT201264)。

摘　　要：激光散斑是阻碍激光投影显示技术发展的一大瓶颈。基于复合散斑衬比度分析法,对影响激光投影系统中复合散斑衬比度的参数进行了分析,即统计独立散斑图样个数N和探测器成像镜头在投影屏幕上的分辨基元面积内的散射光波的相干面元的数量M。可通过调节投影镜头和成像镜头的数值孔径、投影距离及观测距离等参数改变N和M,从而达到改善激光投影系统中散斑现象的目的。并在简化的投影系统中,就随机相位片上照射光斑面积、照明系统数值孔径对激光投影成像中散斑衬比度的影响进行了系统实验分析。实验结果表明,在投影镜头尺寸一定的基础上,适当增加照射在随机相位片上光斑的面积,可有效降低散射屏幕上二次散斑图样的衬比度,且投影镜头数值孔径的减小会增加散斑现象,这为激光投影系统的小型化提出了一大挑战。该结论可为以旋转随机相位片抑制激光投影成像中的散斑提供系统设计指导。Laser speckles create a bottleneck that hinders the development of laser projection display technology.Based on the compound speckle contrast analysis method,the parameters affecting the composite speckle lining ratio in a laser projection system are analyzed.These parameters include the number N of independent speckle samples and the number M of scattered light wave coherent elements within a single imaging-lens resolution element on the projection screen.The occurrence of speckles in the laser projection system can be reduced by changing parameters N and M.These changes can be achieved by adjusting the numerical apertures of the projection-lens and imaging-lens,projection distance,and observation distance.In the simplified projection model,the effects of the random-diffuser spot area and projection-lens numerical aperture on the speckle contrast in laser projection imaging were experimentally analyzed.The results reveal that for a certain size of the projection lens,the contrast of the secondary speckle pattern on the scattering screen can be reduced by increasing the area of the diffuser spot.The occurrence of speckles increases when the numerical aperture is reduced,thereby posing a challenge for the miniaturization of the laser projection system.The findings of this work can provide guidance for the use of a rotating random diffuser in the design of speckle suppression systems for laser projection imaging.

关 键 词：相干光学与统计光学 激光散斑 散斑抑制 复合散斑 随机相位片 散斑衬比度 

分 类 号：O436[机械工程—光学工程]