Title:
OPTICAL PICKUP-USE OBJECT LENS, OPTICAL PICKUP AND OPTICAL DISK UNIT
Document Type and Number:
WIPO Patent Application WO/2002/069014
Kind Code:
A1
Abstract:
An optical pickup-use object lens (15) having a numerical aperture of at least 0.8, for correcting light, within a wavelength range of several nm based on up to 420 nm, for chromatic aberration at an image point on the optical axis. The object lens comprises, in an arranged order from a light source, a first lens group (GR1) having a compound plane (S¿2?) of a refraction plane (S¿2r?) and a diffraction plane (S¿2d?), and a second lens group (GR2) having a positive refraction power, wherein the compound plane of the first lens group is formed by adding a diffraction plane having a positive refraction power onto an aspherical refraction plane having a negative refraction power, and a lens constituting the second lens group uses a single lens including at least one aspherical plane. This small object lens enables an effective chromatic aberration correction and a laser beam condensation up to a diffraction limit.
More Like This:
Inventors:
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
HINENO SATOSHI (JP)
Application Number:
PCT/JP2002/001866
Publication Date:
September 06, 2002
Filing Date:
February 28, 2002
Export Citation:
Assignee:
SONY CORP (JP)
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
TAKAHASHI TOYOKAZU (JP)
HINENO SATOSHI (JP)
International Classes:
G02B9/04; G02B27/00; G11B7/135; G11B7/22; (IPC1-7): G02B13/00; G02B13/18; G11B7/135
Foreign References:
| JP2001296472A | 2001-10-26 | |||
| US5629799A | 1997-05-13 | |||
| JPS634213A | 1988-01-09 |
Attorney, Agent or Firm:
Koike, Akira (Yamato Seimei Bldg. 1-7, Uchisaiwai-cho 1-chome Chiyoda-ku Tokyo, JP)
Download PDF: