Patent ID: 9267820
Filing Date: 2016-02-23
CPC Classification: G01D

Claim Text:
1. A two-dimensional absolute encoder comprising: a scale having a plurality of marks arranged thereon along a first direction and a second direction different from each other; a detector configured to perform first detection that detects a first number of marks arranged in the first direction and second detection that detects a second number of marks arranged in the second direction; and a processor configured to obtain absolute positions of the scale in the first direction and the second direction based on outputs from the detector, wherein each of the plurality of marks has one of a plurality of different characteristic values each corresponding to a combination of a quantized first code for indicating a position in the first direction and a quantized second code for indicating a position in the second direction, a number of the plurality of different characteristic values being smaller than a number of the combinations; and the processor is configured to generate a first code sequence including the first number of the first codes based on a result of the first detection, obtain an absolute position of the scale in the first direction based on the first code sequence, generate a second code sequence including the second number of the second codes based on a result of the second detection, and obtain an absolute position of the scale in the second direction based on the second code sequence.