Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
2000-06-23
2004-07-06
Tran, Thang V. (Department: 2653)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S112100
Reexamination Certificate
active
06760296
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical integrated device, an optical pickup, and an optical disk apparatus, and is applicable to an optical disk apparatus for playing back a compact disk and a DVD (Digital Video Disk). The present invention resides in dividing feedback light with a diffraction grating and detecting the divided feedback light with a light-detecting element. Laser beam sources having different wavelengths are spaced a predetermined distance from each other in order to make up for the difference between diffraction angles of the diffraction grating thereby enabling access to a plurality of types of optical disks with a simple arrangement.
2. Brief Description of the Related Art
Conventional compact disk players as optical disk apparatus have an optical pickup which applies a laser beam to the information-recorded surface of a compact disk and processes detected feedback light of the applied laser beam for thereby reproducing various types of data recorded on the compact disk.
Optical pickups for such compact disk players are classified into a group in which a light-emitting element and a light-detecting element are disposed independently of each other, and another group in which a light-emitting element and a light-detecting element are integrally combined with each other. The optical pickups of the latter group are smaller in size and more reliable than the optical pickups of the former group.
Optical disk apparatus for playing back DVDs may be reduced in size and simplified in structure if their optical pickup is constructed using an optical integrated device. It is considered highly convenient if such optical disk apparatus for playing back DVDs are capable of playing back compact disks.
In such an application, if a light-emitting element and a light-detecting element for DVDs and a light-emitting element and a light-detecting element for compact disks are integrally combined into an optical integrated device, then an optical disk apparatus can be constructed which is capable of playing back both compact disks and DVDs.
However, when the light-emitting elements and the light-detecting elements are integrated respectively for DVDs and compact disks, the optical integrated device tends to be complex in structure. The present invention has been made in view of the above shortcomings of the prior art, and provides an optical integrated device, an optical pickup, and an optical disk apparatus which are capable of accessing a plurality of types of optical disks with a simple arrangement.
BRIEF SUMMARY OF THE INVENTION
It is an overall object of this invention therefore to provide an optical disk apparatus of the type described that is capable of accessing a plurality of types of optical disks with an uncomplicated arrangement.
To solve the above problems, the invention is applied to an optical integrated device, an optical pickup, or an optical disk apparatus. The optical integrated device comprises a first laser beam source for emitting a first laser beam having a first wavelength, a second laser beam source spaced a predetermined distance from the first laser beam source, for emitting a second laser beam having a second wavelength different from the first wavelength, a diffraction grating for dividing each of the feedback light corresponding to the first laser beam and the feedback light corresponding to the second laser beam into a plurality of rays, and a light-detecting element for commonly detecting the feedback light corresponding to the first laser beam and the feedback light corresponding to the second laser beam, with respect to at least a certain one of the rays divided by the diffraction grating.
According to the invention, the second laser beam source is spaced a predetermined distance from the first laser beam source, and the distance may be selected to divide the feedback light into a plurality of rays with the diffraction grating and detect feedback light corresponding to the first laser beam and feedback light corresponding to the second laser beam with the common light-detecting element, so that the overall structure can be simplified.
REFERENCES:
patent: 5621716 (1997-04-01), Kojima et al.
patent: 5982732 (1999-11-01), Yamanaka
patent: 6240053 (2001-05-01), Akiyama
patent: 6272098 (2001-08-01), Takahashi et al.
Baba Tomohiko
Imai Satoshi
Nakano Satoshi
Sato Katsutoshi
Yukawa Hiroaki
Kananen Ronald P.
Rader & Fishman & Grauer, PLLC
Sony Corporation
Tran Thang V.
Vuong Bach
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