光栅制造与装配误差对双光栅泰伯效应微位移检测的影响分析

Analysis of the impact of grating fabrication and assembly errors on the micro-displacement detection based on double-layer grating Talbot effect

摘要:

双光栅泰伯效应微位移传感器具有分辨率高、 抗电磁干扰能力强等优势,但其精度易受光栅加工和装配误差的影响。本文利用COMSOL仿真软件,对光栅加工过程中的栅线宽度、光栅厚度、占空比以及双光栅装配过程中的层夹角、栅线夹角和双光栅间距进行误差仿真分析。最终结果表明,光栅周期加工可允许误差范围小于±0.1 μm,光栅厚度对光栅衍射效率影响可忽略不计,光栅占空比最优参数为0.5；双层光栅层夹角与栅线夹角对光栅衍射效率影响较大,双光栅层夹角可允许误差小于1°,栅线夹角可允许误差小于0.1°,光栅间距可允许误差小于±0.1 μm。上述分析将有助于后续对各类误差进行补偿,进而保证双光栅泰伯效应系统的高精度微位移检测。

Abstract:

The micro-dsplacement sensor based on double-layer grating Talbot effect has the advantages of high resolution and anti-electromagnetic interference,however,its accuracy is affected by the fabrication and assembly errors of gratings. In this paper,COMSOL software is employed to simulate and analyze the influence of the fabrication errors (including the line width,thickness and duty cycle of the grating) and assembly errors (including the included angle of layers,included angle of grid lines and grating spacing of double-layer grating) of the gratingsThe final results shows that the allowable error of the grating period is less than ±0.1 μm,the influence of the thickness of the grating on the diffraction efficiency is negligible,and the optimal value of the duty cycle is 0.5.In addition,the included angle of layers,included angle of grid lines of double-layer grating also have a significant impact on the diffraction efficiency,the allowable errors of included angle of layers, included angle of grid lines and grating spacing of double-layer grating are less than 1°,0.1° and ±0.1 μm,respectively.The analysis will be helpful to compensate for various types of errors in the future,thereby ensuring high-precision micro-displacement detection system based on grating Talbot effect.