The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1989
Filed:
Sep. 04, 1987
Ryozo Hiraga, Yokohama, JP;
Hiroshi Echizen, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A wafer position detecting device includes a laser source, a mirror for receiving the laser beam and reflecting it to a photosensor. Optically between the laser source and the photosensor, there is located a wafer cassette containing plural semiconductor wafers in the manner that the optical path of the laser is parallel to the surface of the wafer in the cassette, namely that the laser beam can incident on the edge of the wafer parallel to the surface thereof. Relative movement is caused between the wafer and the laser beam in the direction perpendicular to the wafer surface. The space or the wafer can be detected on the basis of the output of the photosensor.