Title:
対物レンズ及び光ピックアップ装置
Document Type and Number:
Japanese Patent JP4807258
Kind Code:
B2
Abstract:
An objective lens is provided for an optical pickup apparatus at least reproducing information for a first optical disc, and recording and/or reproducing information for second and a third optical discs. The objective lens includes an optical surface including a common area including a diffractive structure having a cross section in a serrated shape and divided into a plurality of ring-shaped zones. Refractive index differences between media arranged at both side of the optical surface for a light flux with one and the other wavelength satisfy a predetermined condition, and the objective lens satisfies a predetermined conditions defined by using an approximate coefficient which makes a Pearson's correlation coefficient R satisfy 0.99998≰R when a depth parallel to the optical axis of step differences between the ring-shaped zones at a vertical distance from the optical axis is approximated by a least squares method.
Inventors:
Ikenaka Seino
Application Number:
JP2006514071A
Publication Date:
November 02, 2011
Filing Date:
May 24, 2005
Export Citation:
Assignee:
Konica Minolta Opto Co., Ltd.
International Classes:
G02B5/18; G02B13/00; G02B13/18; G02B27/44; G11B7/135; G11B7/00; G11B7/125
Domestic Patent References:
| JP2004030724A | 2004-01-29 | |||
| JP2004062971A | 2004-02-26 | |||
| JP2004071134A | 2004-03-04 |
Attorney, Agent or Firm:
Gwangyang International Patent Office