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:
Jun. 24, 2003
Filed:
Dec. 04, 2000
Katsushige Yanagisawa, Nagano, JP;
Tohru Hotta, Nagano, JP;
Ikuo Kasuga, Nagano, JP;
Satoru Kishita, Tokyo, JP;
Other;
Abstract
An optical system of an optical pick-up device comprises a half mirror and a prism which serve to guide a first laser beam L for a CD and a second laser beam L for a DVD to the optical recording medium side and a common light receiving element The half mirror is set to have a ratio of a reflectance to a transmittance of 5:1 in the first laser beam L to be a P polarized light and the prism is set to have a ratio of a reflectance to a transmittance of 1:3 in the first laser beam L having a P polarization component and an S polarization component mixed. The first laser beam for a CD can be guided to the optical recording medium without a light quantity loss. At the same time, a return light Lr can be sent in a sufficient light quantity back to the light receiving element for servo signal generation. Therefore, it is possible to implement a reliable CD recording operation by using the first laser beam.