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:
May. 19, 1998
Filed:
Nov. 02, 1995
Hiroyuki Yamazaki, Tokyo, JP;
Takashi Matsumaru, Tokyo, JP;
Konica Corporation, Tokyo, JP;
Abstract
A device for recording and reproducing on an optical information recording medium, includes a light source composed of a semiconductor laser to emit a divergent luminous flux; an objective lens to receive the divergent luminous flux and to converge the divergent luminous flux onto the optical information recording medium; and a tracker for tracking a converged luminous flux on the optical information recording medium by moving the objective lens in a direction perpendicular to an optical axis. The objective lens has an astigmatism so that a quantity of the astigmatism of a wavefront emitted from the objective lens shows a minimum value at a position where the objective lens is moved in the direction perpendicular to the optical axis by a tracking operation of the tracker.