| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an encoder capable of preventing deterioration of its measurement accuracy even if detection of Lissajous signals is stopped. <P>SOLUTION: An encoder includes: a scale; a light source for emitting light to the scale and varying light quantity in accordance with a current to be supplied; a light receiving section for receiving light reflected on the scale and outputting two-phase sine-wave signals out-of-phase; an error detector for detecting errors including an amplitude error on the basis of an ideal Lissajous waveform included in Lissajous waveforms formed with the two-phase sine-wave signals to dynamically update a current correction value with a new correction value obtained by accumulation calculation of detected errors; and a light source driving processing section for adjusting a current to be supplied to the light source in accordance with the correction value based on the amplitude error. <P>COPYRIGHT: (C)2013,JPO&INPIT |
