光栅传感器的各部分几何参数对莫尔信号调制度的影响

Influences of Several Parameters of Grating Sensor on the Modulation Depth of Moire Signal

本文以非相干照明的成像理论为依据,推导了计算莫尔光电信号调制度的理论公式。由公式可知,莫尔光电信号的调制度与光源的几何形状及尺寸、光栅的衍射效应、开口比、光栅副间隙、接收光栏的几何形状与尺寸等因素有关。讨论了非准直光照明时,光栅副间隙对莫尔条纹的周期和倾角的影响,比较了非准直光和准直光照明下莫尔光电信号调制度的变化情况。井以实验验证了理论公式。

In this paper the theoretical expressions of modulation depth of moire signal under the incoherent illumination are derived. It follows as a consequence that, the modulation depth of moire signal is in relation to the following factors: the geometric shape and dimensions of light source, the di- ffraction effect of grating, which relates to the line numbers of grating, the line and space ratis, the gap of grating pair, the geometric shape and dim- ensions of receiving window, etc. In addition, the influences of gap of grating pair on the period and inclination of moire fringes under the nonco- llmated illumination are discussed, and the comparisions of the changes of modulation depth of moire signals under the noncollimated illumination with that under the collimated illumination are made. Finally, some experiment results are given to verify the theoretical expresions.