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:
Dec. 19, 1989
Filed:
May. 26, 1988
Masaki Kobayashi, Yamanashi, JP;
Minemasa Ohta, Yamanashi, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Pioneer Video Corporation, Yamanashi, JP;
Abstract
Herein disclosed is a device for accurately measuring an angular deviation of a flat plate such as a video disk and a digital audio disk. A light beam emitted from a light source is obliquely made incident on the flat plate. A light beam reflected by the flat plate is refracted by a convex lens and detected by a semiconductor position-sensitive detector. The convex lens and the position-sensitive detector are disposed in such a manner that the distance between a reflection point on the flat plate and the convex lens and the distance between the convex lens and the position-sensitive detector become two times the focal length and the focal length of the convex lens, respectively.