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. 25, 1987
Filed:
Jun. 14, 1985
Yuzo Ono, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A focus error detector for an optical head utilizes a transmission type diffraction grating and an optical system for converging a beam issuing from a light source onto an object and converting light reflected from the object to a collimated beam to cause the collimated beam to become incident to the diffraction grating at a proper angle of incidence. A photodetector having a plurality of light-sensitive sections, is positioned relative to the grating such that it receives rays diffracted substantially from the grating in the direction of reflection of the diffraction grating. Photodetector data are used to calculate focus correction signals which are supplied to servo-mechanisms providing physical adjustments to the optical system.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile