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:
Jun. 10, 1997
Filed:
May. 23, 1996
Jun-ichi Takahashi, Tokyo, JP;
NEC Corporation, , JP;
Abstract
An optical head device which has: a light source for projecting laser light; a beam splitter for reflecting the laser light onto an optical disk; an objective for focusing the reflected light on an information recording surface of the optical disk to form a micro spot thereon; an optical detector for receiving a light component transmitted through the beam splitter of light reflected on the information recording surface and converting the light component into an electrical signal; a variable aperture device for varying a diameter of the micro spot according to an external input, the variable aperture device being provided between the beam splitter and the objective; and a variable rotation angle diffraction grating for varying a rotation angle of a sub-beam for tracking of the laser light according to an external input, the variable rotation angle diffraction grating being provided between the light source and the beam splitter.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile