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:
Oct. 12, 2004
Filed:
Dec. 18, 2000
Ikuya Kikuchi, Tsurugashima, JP;
Takanori Maeda, Tsurugashima, JP;
Mitsuru Sato, Tsurugashima, JP;
Masayuki Iwasaki, Tsurugashima, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
A variable optical unit is provided with at least two phase-shift regions for providing light with phase differences. Phase-shift amount of the phase-shift region is adjusted by the applied voltage in accordance with birefringence of an information medium. A light beam emitted from a light source is incident on the variable optical unit through a collimator lens and a beam splitter. The light beam is polarized in accordance with the aforementioned phase-shift amount of the variable optical unit and converged by an objective lens to radiate the information medium. The reflected light polarized due to the effect of the birefringence of the information medium is polarized again according to the phase-shift amount of the variable optical unit. The reflected light is thereby polarized in the direction in which the beam splitter can reflect the reflected light and then the reflected light reflected by the beam splitter is detected by the condenser lens and an optical detector.