狭缝投影位置传感技术及其在精密定位中的应用

Position Sensor with Slit Projection for Precision Positioning

提出了一种基于狭缝投影的位置传感技术,阐述了此技术的传感原理及其在精密定位中的应用。准直激光束照明的投影狭缝由一个透镜以掠入射角度投影在被测物体上,狭缝投影经过被测物体表面的反射和另一个透镜的成像在探测双缝上形成投影狭缝像。探测双缝放大成像在双像限探测器上,投影狭缝像透过探测双缝的光强分别被双像限探测器的两个像限所接收,通过检测双像限探测器两个像限上的光强获得被测物体的位置。实验验证了此传感技术的可行性,其位置重复测量偏差小于32 nm(1σ)。

A position sensor based on slit projection is developed. Its measurement principle and application in precision positioning are described, A projection slit is illuminated by a collimated laser beam, The projection slit is projected onto an object to be measured with grazing incidence through a lens. After being reflected by the object, the projection slit is imaged on a detection double slit through another lens. A magnified image of the detection double slit is formed on a bi-cell detector, and the light intensities through the detection double slit are detected by the bi-cell detector. In this way, the position of the measured object can be obtained by detecting the light intensities on two separated parts of the bi-cell detector, In the experiment, the feasibility of the sensor is verified, The repeatability variation is less than 32 nm （1σ）.