基于二维零位光栅的高精度平面定位系统

A Two-Dimensional Zero-Reference Grating-Based High-Precision Planar Positioning System

随着微电子工业和纳米加工技术的快速发展,对超高精度的定位基准的要求也越来越高．提出一种基于特殊编码的非周期性二维零位光栅的平面定位传感器,采用在二维方向上的非周期性鳊码产生一个表征鲍对零位的最大输出峰．当两块二维零位光栅的相互位置完全对准时,透过的光强达到峰值,峰值的半宽仅为一个光栅栅格尺寸：当两块二维零位光栅的相互位置稍有移动时,透过光强急剧衰减．用光电接受器件接受透射光强信号,经过电路处理,反馈给定位驱动装置,可以在平面内同时实现x和y方向高精度的定位要求．采用栅格常数为5μm的光栅做实验,可以达到优于20nm的定位精度．实验表明,该平面定位系统可以满足高精度平面定位的要求,有着广泛的应用空间．

With the development of micro fabrication and nano technology, the demand for ultrahigh precise positioning is becoming more and more important. In this article, a planar positioning sensor based on specially coded two-dimensional zero-reference grating is proposed, the zero reference signals are obtained from the nonperiodic code in both x and y direction. When the two gratings are in the correct alignment position, the maximal output signal will be detected, the width of the peak is only one element width of the grating. If there is relatively small misalignment in either the x direction or the y direction, the output intensity will fall rapidly. The output intensity is detected by a photodiode and transmitted to the positioning actuator to meet the needs for high-precision planar positioning. The width of the grating elements is 5 μm, therefore the accuracy better than 20 nm can be reached. Experiment proves that this system has the advantages of ultrahigh precision and both x and y directions positioning.