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. 02, 2011
Filed:
Feb. 27, 2008
Kenichi Shimada, Yokohama, JP;
Tatsuro Ide, Kawasaki, JP;
Kevin R. Curtis, Longmont, CO (US);
Ken E. Anderson, Longmont, CO (US);
Kenichi Shimada, Yokohama, JP;
Tatsuro Ide, Kawasaki, JP;
Kevin R. Curtis, Longmont, CO (US);
Ken E. Anderson, Longmont, CO (US);
Hitachi, Ltd., Tokyo, JP;
InPhase Technologies Inc., Longmont, CO (US);
Abstract
In holographic recording, it is important to form stably an interference fringe between a reference beam and a signal beam in a holographic storage medium. To suppress factors degrading stability of the interference fringe, such as fluctuation of atmospheric air, position displacement of optical components and the like during propagation of the reference and signal beams, an optical pickup and an optical information recording/reproducing apparatus adopt an optical system structure providing a higher proportion of optical components shared by the reference and signal beams optical path than conventional optical system structure. To increase the proportion of shared optical components, the signal beam and the reference beam pass through the PBS prism as parallel beams and a concave lens is placed on a reference beam path just before the objective lens.