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:
Sep. 07, 1999
Filed:
Mar. 11, 1997
Masayuki Iwasaki, Saitama, JP;
Sakashi Ootaki, Saitama, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A compatible optical pickup for DVD and CD in which, between an objective lens and a polarizing beam splitter, there is disposed a transmission type liquid crystal panel which has transparent electrodes formed with an aperture pattern having a predetermined configuration which gives transmitted light a phase difference, such as 1/4 of a wavelength or an odd multiple thereof. The liquid crystal panel is tilted and disposed with a predetermined angle between an objective lens and said laser light source for causing a phase difference in a laser beam emitted from said laser light source, whereby the liquid crystal panel is tilted with a predetermined pretilted angle .theta. so that liquid crystal molecules are aligned, in perpendicular relation to (for P-type liquid crystal) or in parallel relation with (for N-type liquid crystal) an optical axis of the objective lens at the time when no voltage is applied.