Patent ID: 6803560
Filing Date: 2004-10-12
Classification: G01D

Abstract:
An optical encoder comprising:a light irradiating system; an optical scale having a grating for transmitting or reflecting incident light; four light-receiving elements disposed essentially in a line; and an optical system constructed so as to amplitude-modulate light, traveling from said light irradiating system to said optical scale and transmitted or reflected by the grating, by a dividing element in which a plurality of V-shaped grooves are juxtaposed, and so as to divide the amplitude-modulated light into beams along a plurality of different directions to guide the beams to respective light-receiving elements; wherein said dividing element is comprised of repetitions of such structure that a plurality of V-grooves, each having two planes of mutually different slope magnitudes, are juxtaposed at a predetermined pitch to form four beams having different phases arranged for reception by the four light-receiving elements.