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:
Mar. 11, 2008
Filed:
Jul. 01, 2003
Takeshi Mizuno, Tokyo, JP;
Takeshi Mizuno, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical-recording-medium playback apparatus includes a first optical member which focuses light emitted from a light-emitting unit on an optical recording medium, a second optical member which focuses light reflected by the optical recording medium, a light-receiving unit which receives the light focused by the second optical member, and a pinhole which is disposed between the second optical member and the light-receiving unit. The focal point of the light focused by the first optical member and that of the light focused by the second optical member correspond to each other. Accordingly, when the pinhole only transmits light which passes through positions around the focal point of the second optical member, stray light from positions around the focal point of the first optical member (in particular, light reflected by recording layers other than the one from which information is read out) can be removed.