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. 15, 2000
Filed:
Nov. 04, 1997
Kenji Yamamoto, Tokyo, JP;
Isao Ichimura, Kanagawa, JP;
Fumisada Maeda, Tokyo, JP;
Toshio Watanabe, Kanagawa, JP;
Kiyoshi Ohsato, Chiba, JP;
Sony Corporation, , JP;
Abstract
The present invention provides an objective lens unit which can be simultaneously adjusted to an NA specification and a substrate thickness of an optical recording medium. The objective lens unit for applying a beam to an optical recording medium so as to read and/or record from/to the optical recording medium includes: a first lens; a second lens; a cylindrical frame for movably supporting the second lens with respect to the first lens in a direction of an optical axis; and diaphragm means provided in the vicinity of the second lens and movable together with the second lens in the direction of the optical axis, for shading a part of the beam to be applied to the optical recording medium. The present invention also provides a recording/reproduction apparatus having the aforementioned objective lens unit, enabling to preferably write and read a data signal into/from an optical recording medium of different specifications.