OPTICAL ABSOLUTE VALUE ENCODER

摘要

PROBLEM TO BE SOLVED: To provide an optical absolute value encoder that reduces a read error by decreasing an unstable area generated with making high resolution to then realize detection with high accuracy and high resolution. SOLUTION: A photodetector 700 detects an irradiated beam radiated from an LED 6 via a detecting track 5a consisting of an M series slit array and an interpolation multiplication slit array. The photodetector 700 comprises a beam receiving cell array A group and a B group having a beam receiving cell width 0.35P-0.40P, and a beam receiving cell array A' group and B' group having a beam receiving cell width 0.5P for an interpolation multiplication assuming that a periodical pitch between cells is a P. A detection signal output by these beam receiving cell arrays is input to the CPU 100 of a printed circuit board 8 and then the information of an absolute position is obtained.