The scale which extends to optical

摘要

PROBLEM TO BE SOLVED: To provide an optical displacement measurement apparatus achieved in downsizing.;SOLUTION: A light source 3 is placed at one side 15 of a scale 9, while a reflective section 5 is placed at the other side 17 of the scale 9. Light L from the light source 3 is reflected by the reflective section 5 obliquely downward and is irradiated to an optical grating 7 of the scale 9 through an optical grating 31. The light is reflected by the optical grating 7 and is received by a first light receiving section 35. A light component L1, which is a portion of the light of the light source 3, is incident on a reference signal mark 67 of the scale 9 from the light source 3 and is reflected thereby to be received by a second light receiving section 69.;COPYRIGHT: (C)2006,JPO&NCIPI