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:
Jan. 06, 2004
Filed:
Feb. 28, 2003
Applicant:
Inventor:
Masayuki Iwasaki, Tsurugashima, JP;
Assignee:
Pioneer Electronic Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/00 ;
U.S. Cl.
CPC ...
G11B 7/00 ;
Abstract
A liquid-crystal panel is placed in an optical path of an optical beam from a light source to a recording surface of a recording medium for compensating wavefront aberration of the optical beam by giving a phase difference to the optical beam. The liquid-crystal panel comprises a layer of a liquid crystal material having an index of birefringence, wherein the product of the index of birefringence and thickness of the layer of the liquid crystal material is 0.4 &mgr;m or more.