Title:
OPTICAL PICKUP DEVICE AND SEMICONDUCTOR LASER APC CIRCUIT
Document Type and Number:
Japanese Patent JPH1027378
Kind Code:
A
Abstract:
To provide an optical pickup device capable of converging lights up to a diffraction limits for both optical disks different in substrate thickness by using a bi-focal hologram and preventing shifting of diffraction states in photodetectors.
A hologram element 109 is disposed between a semiconductor laser 101 and a collimator lens 104, a light 110 directly transmitted without being diffracted in the hologram element 109 is converged on a DVD disk 108 by an objective lens 105, a primary diffracted light diffracted by the hologram element 109 is converged on a CD disk 106 thicker than the DVD disk 108 by the objective lens 105.
Inventors:
TAGUCHI AISAKU
YUKI YOICHI
MOTOJIMA SUMIO
JUSO HIROMI
YUKI YOICHI
MOTOJIMA SUMIO
JUSO HIROMI
Application Number:
JP18522996A
Publication Date:
January 27, 1998
Filing Date:
July 15, 1996
Export Citation:
Assignee:
SHARP KK
International Classes:
G02B5/32; G11B7/09; G11B7/125; G11B7/135; H01S5/00; (IPC1-7): G11B7/135; G02B5/32; G11B7/09; G11B7/125; H01S3/18
Attorney, Agent or Firm:
Shusaku Yamamoto