Patent ID: 9417101
Filing Date: 2016-08-16
CPC Classification: G01D

Claim Text:
1. An optical encoder comprising: a light source; a scale configured to be irradiated by the light source and have a fine pitch pattern whose transmittance or reflectivity changes periodically within a first period in a measuring direction and a coarse pitch pattern whose transmittance or reflectivity changes periodically within a second period which is longer than the first period; a detection sensor array including a plurality of sensor elements arranged along the measuring direction, wherein the detection sensor array is operable under a high resolution detection mode for reading out a signal corresponding to the fine pitch pattern and a low resolution detection mode for reading out a signal corresponding to the coarse pitch pattern, wherein each sensor element within the plurality of sensor elements is configured to receive both lights from the fine pitch pattern and the coarse pitch pattern, wherein a transmittance distribution or a reflectivity distribution of the scale is a distribution obtained by summing up a modulation component which corresponds to the fine pitch pattern and a modulation component which corresponds to the coarse pitch pattern, wherein the fine pitch pattern and the coarse pitch pattern are arranged in a direction perpendicular to the measuring direction.