| US 7,586,621 B2 | ||
| Displacement-measuring optical scale and optical encoder using same | ||
| Hiroshi Watanabe, Utsunomiya (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, (Japan) | ||
| Filed on May 29, 2008, as Appl. No. 12/128,747. | ||
| Application 12/128747 is a division of application No. 11/282184, filed on Nov. 18, 2005, granted, now 7,394,062. | ||
| Claims priority of application No. 2004-338895 (JP), filed on Nov. 24, 2004. | ||
| Prior Publication US 2009/0040529 A1, Feb. 12, 2009 | ||
| Int. Cl. G01B 11/02 (2006.01); G01D 5/34 (2006.01) | ||
| U.S. Cl. 356—499 | 5 Claims |
| 1. An optical encoder, comprising:
an optical scale for generating an incremental signal and a reference position signal; and
a substrate included within the optical scale, which has a first surface and a second surface which is opposite to the first
surface,
wherein a diffraction grating is formed on the first surface of the substrate so as to generate the incremental signal, and
a pattern is formed on the second surface of the substrate, on the same optical axis of the diffraction grating, so as to
generate the reference position signal, and
wherein a light beam which is not used for generating the incremental signal among light beams projected onto the diffraction
grating and reflected by or transmitted though the diffraction grating is incident onto the pattern and used for generating
the reference position signal.
|