Calculation method in photoelectric encoder and photoelectric encoder

摘要

PROBLEM TO BE SOLVED: To provide a photoelectric encoder capable of calculating a relative movement amount between a scale and a head with high accuracy even when a lens array having a plurality of small diameter lenses is used. A photoelectric encoder 1 includes a scale 2, a lens array 5 having a first lens 51 and a second lens 52, a head 3 including a light source 4 and an imaging means 6, and a calculation means 7. The calculation means 7 includes a signal generation unit 71 that generates a sine wave signal, an analysis region extraction unit 72 that extracts the first analysis region H1 and the second analysis region H2, and a second analysis region H2 based on the inter-region distance d. A sine wave signal is generated from the sine wave signal to one end of the first analysis region H1 so as to overlap the sine wave signal of the first analysis region H1, and the generated sine wave signal and the sine wave signal of the first analysis region H1 are combined. A movement amount calculation unit 74 that calculates a relative movement amount based on the sine wave signal synthesized by the signal synthesis unit 73 is provided. [Selection diagram] Fig. 4