| US 7,573,658 B2 | ||
| Optical element holding apparatus and exposure apparatus | ||
| Ichiro Onuki, Kawasaki (Japan); Kenichi Kobayashi, Utsunomiya (Japan); Kenji Yoshida, Utsunomiya (Japan); and Jun Ota, Utsunomiya (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, (Japan) | ||
| Filed on Oct. 26, 2007, as Appl. No. 11/925,271. | ||
| Claims priority of application No. 2006-291938 (JP), filed on Oct. 27, 2006. | ||
| Prior Publication US 2008/0123203 A1, May 29, 2008 | ||
| Int. Cl. G02B 7/02 (2006.01) | ||
| U.S. Cl. 359—822 [359/823] | 3 Claims |
| 1. A holding apparatus, comprising:
a driving part configured to move the optical element; and
a measuring part configured to measure a coordinate of the optical element,
wherein the measuring part includes a first measurement part including an incremental sensor and configured to measure positions
of three points of the optical element in a direction of an optical axis of the optical element, and a second measurement
part including an absolute sensor and configured to measure positions of the three points in the direction of the optical
axis, wherein the holding apparatus is configured to calibrate a measurement value of the first measurement part based on
a measurement value of the second measurement parts,
wherein number of coordinates measured by the measuring part among a degree of freedom of the optical element is greater than
a driving degree of freedom of the driving part.
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