| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an absolute encoder with high resolution. <P>SOLUTION: This absolute encoder includes: a scale in which a plurality of marks including at least two types of marks are arrayed along a first direction with fixed cycles; a detector for detecting the prescribed number of marks in the plurality of marks by a plurality of photoelectric conversion elements arranged along the first direction with pitches smaller than the cycles; and a calculation part for calculating the absolute position in the first direction of the scale with respect to the detector based on the output of the detector. The calculation part generates a data string configured of the prescribed number of data by quantizing the amplitude of each of the prescribed number of cyclic signals output from the detector, and converts the data string into first position data with the cycles as units, and calculates second position data shorter than the length of the cycle with the resolution of the length of divisions obtained by dividing the cycle from the phase of at least one of the prescribed number of cyclic signals, and generates data showing the absolute position in the first direction of the scale by synthesizing the first position data with the second position data. <P>COPYRIGHT: (C)2012,JPO&INPIT |
