Patent ID: 9618370
Date: 2017-04-11
CPC Classifications: G01D

Claim:
1. An optical encoder comprising: a scale provided with a scale pattern that reflects or transmits light from a light source; a sensor configured to receive the light from the scale pattern, the sensor and the scale being moved relative to each other in a relative movement direction; and an intermediate pattern provided between the scale and the sensor, wherein: the sensor is provided with multiple light-receiving element groups each including plural light-receiving elements, the light-receiving elements being arranged on the sensor with a pitch P in the relative movement direction, and outputs of the plural light-receiving elements within each light-receiving element group being added together; the intermediate pattern includes a first pattern to form a first light intensity distribution with a first spatial period shorter than the pitch P and a second pattern to form a second light intensity distribution with a second spatial period longer than the pitch P; a position of the intermediate pattern and a position of the sensor are relatively fixed with each other; and the first pattern and the second pattern are arranged in a direction perpendicular to the relative movement direction.