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:
Mar. 13, 2001
Filed:
Feb. 22, 1999
Yasutada Miura, Hachioji, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
A position detecting apparatus for a semiconductor wafer includes a wafer worktable supported by an X-Y stage. The worktable is rotatable about an axis on a reference center for positioning the wafer. The apparatus also includes a photoelectric sensor arranged to correspond to the edge region of the wafer on the worktable. The photoelectric sensor includes an infrared-ray emitting LED and a collimator lens for applying a parallel luminous flux to the wafer edge region, and a photo diode facing the collimator lens through the wafer edge region, all arranged on the optical axis. The photo diode outputs a signal having a level corresponding to a received light quantity. The photoelectric sensor also includes a light shielding slit plate having a slit arranged on the optical axis.