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. 08, 1987
Filed:
Feb. 27, 1987
Shigeto Kanda, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A tracking error signal is detected by irradiating an information pattern recorded on an information carrying member with first and second light beams, the second light beam being incident on the information carrying member at a position which is spaced from the incidence position of the first light beam at least in the direction orthogonal to the tracing direction of the information pattern, the light beams modulated by the information pattern being independently photoelectrically converted, an envelope-detection being effected with respect to the outputs obtained by the conversion, and on the basis of the output signals formed by the envelope-detection, the tracking error signal being produced.