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. 09, 2007
Filed:
Mar. 04, 2004
Noriaki Nishi, Tokyo, JP;
Masaru Tezuka, Kanagawa, JP;
Noriaki Nishi, Tokyo, JP;
Masaru Tezuka, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical head in which pre-formatted signals may be detected as variations in the amplitude or the phase in the pre-formatted signals are suppressed, and a recording and/or reproducing apparatus employing the optical head, are disclosed. The optical head includes a light source, an objective lensfor condensing a light beam radiated from the light sourceon a recording track of an optical recording medium, and a photodetector unitfor receiving the light beam reflected back from said recording track. The photodetector unitincludes a first light receiving sectionand a second light receiving section. With a track pitch Tp of the optical recording medium, the wavelength λ of the light beam radiated from the light source, the numerical aperture NA of the objective lens and with λ/(Tp·NA)≧4/3, the first light receiving section receives the light of one of two light spot areas lying on both sides of a center area of a light spot of the reflected light beam passing through the center of the light spot for extending along the length of the recording track. The second light receiving section receives the light of the other of the two light spot areas.