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. 24, 2009
Filed:
Jul. 28, 2004
Yoshiaki Komma, Hirakata, JP;
Eishin Mori, Kyoto, JP;
Naoya Hotta, Sagamihara, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical pick-up capable of reproducing information excellently on both CD and DVD, which are significantly different in terms of three kinds of factors, a base material thickness, a wavelength of a light source, and NA, and detecting TE signals by three kinds of methods, that is, the phase difference method, the PP method, and the 3-beam method, which are necessary to record and reproduce information. The optical pick-up is formed by integrating laser light sources having two kinds of wavelengths (λ) for detecting TE signals; photodetectors, and hologram for generating the diffracted light for detecting signals. The distance dbetween the center of the photo detecting portion PDand the light emitting spot of the first semiconductor laser light source and a distance dbetween the center of the photo detecting portion PDand the light emitting spot of the second semiconductor laser light source substantially satisfy the following relationship:λ