全内反射照明光学元件损伤检测信噪比分析  

Signal noise ratio of total internal reflection edge illumination for optics damage inspection

作　　者：彭志涛[1] 魏晓峰[1] 元浩宇[1] 傅学军[1] 陈德怀[1] 孙志红[1] 刘华[1] 徐隆波[1] 

机构地区：[1]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《红外与激光工程》2011年第6期1111-1114,共4页Infrared and Laser Engineering

摘　　要：适合的光学元件照明对终端光学元件损伤检测成像至关重要。基于平板光学元件的全内反射原理,将阵列LED边缘照明光耦合进大口径光学元件,光学元件上疵点处的全内反射条件被破坏,光线从疵点出射,用相机对元件成像,散射光就会在相机CCD上形成疵点的图像,它是暗背景中的亮点,因此图像信噪比很高,解决了损伤检测过程中疵点到底归属于光学系统中哪块光学元件的难题。建立了被检测元件损伤点的信噪比模型,分析了临近损伤元件损伤对检测结果的影响。离线验证结果表明:对于310 mm×310 mm口径的平面光学元件,全口径检测分辨率优于120μm×120μm。Proper illumination of the optics to be imaged is critical for the successful performance of the final optics damage inspection.Based on total internal reflection of flat optics,the light emitting from array LED was coupled into the large aperture optics,the edge illumination methods were employed to illuminate the optics.The flaw on the optic surface disrupted the total internal reflection conditions and caused light to scatter from the optic at the flaw location,the percentage of this scattered light was collected and imaged by the camera,resulting in an image of the flaw,which appeared bright against a dark background,and without the uncertainty of which optics the flaw belongs to.The method of time-sharing illumination of large aperture optics was developed for damage imaging,and the model of signal noise ratio was developed for dark-field imaging mode.The final optics damage inspection based on edge illumination experiment system is developed specifically for the TIL final optics,the least accurately size which can be detected is 120 μm×120 μm.

关 键 词：全内反射照明 损伤检测 暗场成像 

分 类 号：O439[机械工程—光学工程]