US 9,810,555 B2
Absolute encoder that provides increased accuracy against defect in scale thereof
Ko Ishizuka, Saitama (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Apr. 17, 2015, as Appl. No. 14/689,329.
Claims priority of application No. 2014-087591 (JP), filed on Apr. 21, 2014.
Prior Publication US 2015/0300847 A1, Oct. 22, 2015
Int. Cl. G01D 5/347 (2006.01); G01D 5/244 (2006.01); G01D 5/245 (2006.01); G01D 5/249 (2006.01)
CPC G01D 5/34776 (2013.01) [G01D 5/2455 (2013.01); G01D 5/2492 (2013.01); G01D 5/2495 (2013.01); G01D 5/24466 (2013.01); G01D 5/24471 (2013.01); G01D 5/24495 (2013.01); G01D 5/34715 (2013.01); G01D 5/34746 (2013.01); G01D 5/34792 (2013.01)] 10 Claims
OG exemplary drawing
 
1. 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.