Speckle interferometry spatial filters or the like to achieve using phase selection

U.S. Patent Number: 5392121

Abstract: It is an object of the present invention to provide a speckle interference apparatus capable of selecting given phase information at a speed higher than speckle interference fringe patterns with a higher precision. For a speckle interference apparatus in which a light beam from a light source is divided into plural light beams, and one of the light beams is passed through a measuring surface and the other light beam through a reference surface to be superposed respectively for the formation of speckle interference fringe patterns, there are arranged in the optical paths spatial filters having windows for sampling the area of a given phase among the speckle interference fringe patterns. Hence, with such filters, speckle interference fringe patterns of the same phase are produced.

Inventors: Hosaka; Kotaro (Ushiku, JP), Narumi; Hiroji (Kawasaka, JP)

Assignee: Canon Kabushiki Kaisha (Tokyo, JP)

Application Number: 07/953,045

Issued: 1995-02-21

Expired: 2007-02-21

Classes: 356/495

Field of search: 356/347,351,360,359

Click the image above to view patent images at uspto.gov within a frame.

Click here for the fulltext page on uspto.gov within a frame.