Combined convolution diaphragm indicator grating

A combined convolution diaphragm marker grating is formed by a set or multiset of convolution diaphragm small windows in certain rules, in which, the convolution diaphragm is got from convolution operation by different light-transmitting gap width rectangle single slits. By designing a spectrum Gn of the marker grating, amplitude of some ultra harmonics is set to be zero in Gn and amplitude value of ultra harmonics of a coder photoelectric signal is also zero, so the ultra harmonics for suppressing photoelectric signal can be selected. This invention has a stable filter effect, good sine and cosine signals and high modulation degree (reaching to M=0.93), favorable for improving amplitude constancy and reducing signal DC components. 一种组合卷积光阑指示光栅，其光栅部分由一组或多组卷积光阑小窗口按一定规律组合而成，其中卷积光阑由不同透光缝宽矩形单缝通过卷积运算获得。通过设计指示光栅的频谱G#-[n]，使指示光栅的频谱中的某些高次谐波的幅值为零，光电编码器的光电信号的高次谐波的幅值也为零，因此可选择抑制光电信号的高次谐波。本发明滤波效果稳定，信号的正弦性较好、调制度较高(理论调制度可达M＝0.93)，有利于改善正余弦信号的等幅性和有利于减小信号的直流分量等，从而提高光电信号的综合质量，以便提高编码器的细分精度；且不改变光栅编码器的结构及频率响应特性，不增加编码器尺寸，结构紧凑，可在静态到最大工作频率范围工作。