在很多需要较高精度零位信号的设备中,广泛使用编码光栅传感器。为了提高从这种传感器所获得的零位信号的可重复性,必须尽量减小信号脉冲宽度,即减小光栅单元线宽,同时提高信噪比。但是,在减小线宽的同时,由衍射而产生的杂散光变得严重起来,信噪比随之降低。另一方面,从光栅的第一菲涅尔焦面位置公式可以看出,随着线宽的减小,相对移动的两块光栅板之间的距离也要减小,若线宽为0.01mm,当采用0.0008mm波长的红 Among many devices that require higher-precision zero-position signals, coded grating sensors are widely used. In order to improve repeatability of the null signal obtained from such a sensor, it is necessary to minimize the signal pulse width, that is, to reduce the grating cell line width and to improve the signal-to-noise ratio. However, while reducing the line width, the stray light caused by the diffraction becomes severe and the signal-to-noise ratio decreases accordingly. On the other hand, it can be seen from the first Fresnel focal plane position formula of the grating that as the line width decreases, the distance between two relatively moving grating plates also decreases. If the line width is 0.01 mm , When using the wavelength of 0.0008mm red