POSITION MEASURING APPARATUS AND POSITION MEASURING METHOD

摘要

The present invention provides a position measuring device and a position measuring method. The position measuring method includes a step of generating measurement signals by sensing lights reflected by or transmitted through an incremental scale while having phase difference of an angle of 60 degrees within one cycle of the incremental scale; a step of displaying the sensed measurement signals as the sum of first sine waves and third sine waves of a fundamental spatial frequency; and a step of extracting phases of the first sine waves based on the measurement signals.