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:
Aug. 21, 1979
Filed:
Jan. 17, 1978
Akiyoshi Suzki, Tokyo, JP;
Yoichi Hirabayashi, Machida, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed in this specification is a scanning device which scans an object having a flat reflection surface and an inclined reflection surface with an inclination relative to the flat reflection surface such as, for example, a mask and a wafer to be used in manufacturing IC, LSI, etc., with light beam, and detects only the reflected light from the inclined reflection surface with a light detector. In order to make it possible to detect only the reflected light from the inclined reflection surface with the light detector, a telecentric objective lens is used as the scanning lens in this scanning device, and the original point of deflection of the above-mentioned scanning light beam coincides with the center of the pupil of this telecentric objective lens. In addition, a filter is disposed on the pupil surface to intercept light from the flat reflection surface. An optical system between the scanning device and the object is of f-.theta.lens characteristics in order to compensate the non-linearity of the scanning beam caused by uniform angular velocity movement of the scanning device or the like.