Two-dimensional absolute encoder and scale therefor

摘要

A two-dimensional absolute encoder includes; a scale on which marks are arranged at predetermined pitches along first and second directions; a detector configured to detect a number of marks arranged in each direction; and a processor configured to obtain an absolute position of the scale in the each direction based on outputs from the detector. Each mark has one of characteristic corresponding to information of a quantized code used for indicating a position in the each direction. The processor is configured to generate a code sequence including the number of codes based on detection of the number of marks and information corresponding to the characteristic, and to obtain an absolute position of the scale in the each direction based on the code sequence.

主权项

1. A two-dimensional absolute encoder comprising:
a scale on which a plurality of marks are two-dimensionally arranged with a predetermined space therebetween at a predetermined pitch along a first direction and a second direction; a detector configured to detect a first number of marks arranged in the first direction, and to detect a second number of marks arranged in the second direction; and a processor configured to respectively 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 characteristics corresponding to pairs of information of a first quantized code for indicating a position of the scale in the first direction and information of a second quantized code for indicating a position of the scale in the second direction, and the processor is configured to generate a first code sequence including the first number of the first quantized code based on detection of the first number of marks and information of the pairs corresponding to the characteristics, to obtain an absolute position of the scale in the first direction based on the first code sequence, to generate a second code sequence including the second number of the second quantized code based on detection of the second number of marks and the information of the pairs corresponding to the characteristics, and to obtain an absolute position of the scale in the second direction based on the second code sequence.