基于DVD读取头的光学探头电路设计

摘要

As the industrial precision measurement demands more and more high accuracy and resolution, the optical probe has been widely used in industrial precision measurement. The focus error signal (FES) of DVD pickup head, namely S - curve, the part of which has a linear relationship with the out - of - focus distance. So we can take the structure of DVD pickup head for the optical probe with a little improvement, so as to measure the micro - displacement. In the study we have designed a new circuit , the circuit includes focus error signal of the DVD (S curve) processing circuit, LD control circuit etc. By tests, we can get a good S - curve through the circuit, and we could achieve the accurate measurement of the micro - component (geometric dimensions for a few millimeters to a few microns, more precision parameters for the micro nanometer scale). It has simple structure, anti - interference capability, and other outstanding features.%随着工业精密测量对于精度和分辨率的要求越来越高,光学探头在工业精密测量中得到了广泛的应用.由于DVD读取头的聚焦误差信号FES(Focus Error Signal)即S曲线的一部分与失焦距离成线性关系,因此稍作改进就可以做光学探头,用来进行微小位移的测量[1].文中给出了其电路设计,该电路分成两个部分,一个是LD功率自动控制电路,一个是FES获取电路.经过实验测试,利用该电路可以获得良好的S曲线,可实现对微器件(几何尺寸数毫米至数微米,精度参数多为微纳米数量级)的精确测量.该电路设计具有结构简单、抗干扰能力强等突出优点.