Title:
OBJECTIVE LENS FOR OPTICAL DISK AS WELL AS OPTICAL HEAD DEVICE USING THE SAME AND OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE
Document Type and Number:
Japanese Patent JP3515712
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an objective lens which is composed of one element of lens and is capable of satisfying good condensing characteristics meeting any of two kinds of output disks varying in substrate thicknesses.
SOLUTION: The objective lens 2 is composed of the single lens of a both side aspherical surface and the surface 3 on a light source side is formed as a rotationally symmetric aspherical surface. The surface on the optical disk 6 side of the objective lens 2 is divided into an inner peripheral region 4 and an outer peripheral region 5 and the boundary between the inner peripheral region 4 and the outer peripheral region 5 is provided with a difference in level 7 of about 0.3 μm (of the optical axis direction) nearly parallel to the optical axis. Spherical aberrations are corrected in correspondence to the optical disks of the different substrate thicknesses in the inner peripheral region 4 and outer peripheral region 5 of the objective lens 2.
Inventors:
Tanaka, Yasuhiro
Yamagata, Michihiro
Sasano, Tomohiko
Yamagata, Michihiro
Sasano, Tomohiko
Application Number:
JP17717799A
Publication Date:
April 05, 2004
Filing Date:
June 23, 1999
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G02B13/00; G02B13/18; G11B7/135; (IPC1-7): G02B13/00; G02B13/18; G11B7/135
Attorney, Agent or Firm:
池内 寛幸 （外１名）
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