ENCODER

摘要

PROBLEM TO BE SOLVED: To constitute a signal called a Z signal which provides a measurement reference value and which has not been implemented before or signals for detecting an optical system for measuring the number of revolutions and an optical system to form light called A phase and B phase for detecting a travelling or rotating direction in one micro encoder to be incorporated in a compact motor and a robot arm and used. SOLUTION: By providing one pattern for generating a Z signal at a location corresponding to a reference location within the range of extent of a light beam with which the surface of a scale 9 to form A-phase and B-phase light is irradiated in the vicinity of a periodic pattern on the scale 9, three signals of A phase, B phase and the Z signal are obtained by one beam. The light beam with which the scale 9 is irradiated is inclined with respect to the surface of the scale 9 for performing this measurement.