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. 02, 1998
Filed:
Feb. 09, 1996
Kenji Inoue, Hyogo, JP;
Makoto Umetani, Osaka, JP;
Hidenao Kataoka, Osaka, JP;
Yoshiyuki Shimizu, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An aspherical lens, which is to be used as an objective lens for an optical pickup of an optical disc apparatus, has at least one optical functional surface of the lens formed to be rotationally asymmetric so as to generate astigmatism of axial wavefront aberration for cancelling off-axis astigmatism. The lens is manufactured by press molding an optical material such as glass or resin. At least one of the dies is formed by etching a rotationally symmetric surface of a base material, unevenly. Thereby, the etched surface becomes rotationally asymmetrically aspherical in shape.