| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical position measuring apparatus which generates scan detection signals to which polarization coding is performed and whose phases are shifted, and is constituted as simply as possible. <P>SOLUTION: The present invention relates to an optical position measuring apparatus for detecting a relative position between a reference scale and a scan detection plate which are movably arranged to be mutually relative along at lest one measuring direction. A light flux emitted from a light source is divided into at least two spectroscopic light fluxes for orienting polarization states at a right angle between each other by a first lattice. The spectroscopic light fluxes are integrated again to become one synthetic light flux, and a plurality of scan detection signals relevant to movement are generated in a detection unit from the synthetic light flux. Polarization means is arranged on light paths of the spectroscopic light fluxes, a polarization action of the polarization means to the spectroscopic light fluxes to be made incident on the light paths is periodically updated by using a polarization period along a degree of freedom of a motion of the reference scale, and the polarization period of the polarization means at the time is larger than a scale period of the first lattice. <P>COPYRIGHT: (C)2012,JPO&INPIT |
