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:
Jan. 30, 2001
Filed:
Aug. 28, 1998
Seiji Kajiyama, Gifu, JP;
Yasuyuki Kanou, Gifu, JP;
Masato Yamada, Aichi, JP;
Yoichi Tsuchiya, Gifu, JP;
Shuichi Ichiura, Gifu, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
The optical pickup device includes a two wavelength semiconductor laser (,) selectively generating a laser beam having the wavelength of 635 nm and laser beam having the wavelength of 780 nm, a collimator lens (,), a hologram (,) formed on a surface of collimator lens (,), a polarizing glass (,) having an annular polarizing region (,) and an objective lens (,). Hologram (,) does not diffract the laser beam having the wavelength of 635 nm, and diffracts outward the laser beam having the wavelength of 780 nm. Therefore, virtual light source of the laser beam having the wavelength of 780 nm comes closer to the collimator lens (,) than the light source of the laser beam having the wavelength of 635 nm. Therefore, objective lens (,) focuses the laser beam having the wavelength of 635 nm on a recording surface of a transparent substrate (,) of a DVD, and focuses the laser beam having the wavelength of 780 nm on a recording surface of a transparent substrate (,) of a CD-R. Accordingly, the optical pickup device is capable of reproducing both DVD and CD-R having transparent substrates of different thicknesses.