Absolute encoder that provides increased accuracy against defect in scale thereof
AssigneeCanon Kabushiki Kaisha
InventorKo Ishizuka
Life of this patent
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Abstract
There is provided an absolute encoder advantageous in accuracy of an output thereof against a defect in a scale thereof. In the absolute encoder, a detector detects a part of an array of marks of the scale, and outputs a data sequence corresponding to the part. A processor stores information indicating a correspondence between each of a plurality of code sequences and an absolute coordinate of motion of the scale, and outputs information of the absolute coordinate based on the data sequence and the information. The processor detects an error of the data sequence, and performs rewriting of the information based on the detected error.
Claims10
An absolute encoder comprising:
- a scale including an array of marks;
- a detector configured to detect a part of the array of marks and output a data sequence corresponding to the part;
- a memory storing information indicating a correspondence between each of a plurality of code sequences and an absolute coordinate of motion of the scale;
- and
- a processor connected to the memory and configured to:
- detect an error of the data sequence based on a degree of correlation between the data sequence and each of code sequences as a part of the plurality of code sequences in the information;
- perform rewriting of a plurality of code sequences as a part of the plurality of code sequences in the information based on the detected error;
- and
- output information of the absolute coordinate based on the data sequence and the information.
Dependencies are inferred from the claim text.