Title:
【発明の名称】光学式情報再生装置および記録媒体
Document Type and Number:
Japanese Patent JP3063805
Kind Code:
B2
Abstract:
Light emitted from a semiconductor laser is collimated by a collimator lens into a parallel beam. The parallel beam enters a phase plate which provides a phase difference of pi to a half of the beam. The beam, which has passed through the phase plate, enters an objective lens and is converged onto an optical disc. The optical disc has a number of mark sets along the track, each mark set comprising optically detectable two marks. The beam from the optical disc is collected into the objective lens and is reflected by a polarized beam splitter into a light detector. The output from a light-element of the light detector is delivered to a differential amplifier and a summing amplifier. The outputs from the differential amplifier and summing amplifier are input to a divider. The output from the divider is delivered to an information reproducing unit. The information reproducing unit reproduces information recorded on the optical disc on the basis of the input, and outputs the reproduced information.
Inventors:
Chiaki Sato
Application Number:
JP419092A
Publication Date:
July 12, 2000
Filing Date:
January 13, 1992
Export Citation:
Assignee:
Olympus Optical Co., Ltd.
International Classes:
G11B7/00; G11B7/005; G11B7/007; G11B7/013; G11B7/135; (IPC1-7): G11B7/005; G11B7/007; G11B7/135
Domestic Patent References:
| JP428016A | ||||
| JP4262814A | ||||
| JP4247329A | ||||
| JP3141033A |
Attorney, Agent or Firm:
Takehiko Suzue