Title:
OPTICAL PICKUP OBJECTIVE, OPTICAL PICKUP, AND DISK DRIVE
Document Type and Number:
WIPO Patent Application WO/2002/103430
Kind Code:
A1
Abstract:
An objective for an optical pickup used for recording or reproducing an information signal on or from an optical disk. The objective comprises a resin layer (21) and a glass lens (22). The resin layer (21) has an aspherical first surface (S1) and an aspherical second surface (S2)in order from the object side. At least either of the surfaces includes a diffraction surface. The lens has a spherical second surface (S2) and an aspherical third surface (S3). The chromatic aberration to a wavelength range within several nanometers from a reference wavelength of 420 nm or less is corrected on the image surface on the optical axis is corrected. The objective has a numerical aperture (NA) of 0.8 or greater. The objective focuses a laser beam close to the diffraction limit on the image plane.
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Inventors:
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
HINENO SATOSHI (JP)
Application Number:
PCT/IB2002/001755
Publication Date:
December 27, 2002
Filing Date:
May 22, 2002
Export Citation:
Assignee:
SONY CORP (JP)
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
International Classes:
G02B27/00; G11B7/135; (IPC1-7): G02B13/00; G02B13/18; G11B7/135
Foreign References:
| JPH09311271A | 1997-12-02 | |||
| JPH06331887A | 1994-12-02 | |||
| JP2000035535A | 2000-02-02 | |||
| JP2001194581A | 2001-07-19 |
Attorney, Agent or Firm:
Koike, Akira (Toranomon 2-chome Minato-ku, Tokyo, JP)
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