MDCP: Patent Abstact US05003521: Optical disk discriminating device

US05003521 Optical disk discriminating device

Assignee Sony Corporation

Assign./Filed March 26, 1991/ Aug. 18, 1988

Inventors Yoshida; Tadao, Fujiie; Kazuhiko, Ando; Ryo

Summary Discriminating between recordable and pre-recorded discs.

Abstract An objective lens (3) of an optical pick up head (10) is moved in a direction of the optical axis, and a signal level of the output detected by the optical pick up head (10) before and after a focussed state is compared with predetermined reference levels (Vref<SUB>1</SUB>) and (Vref<SUB>2</SUB>) level comparators (32) and (33), In order to discriminate the reproduction-only disk from the recording disk by utilizing a difference in the reflection factor on the recording surface on the optical disk (20). Operation of the optical disk recording/reproducing apparatus is automatically switched over depending upon the kind of the optical disk.

US05003521	Optical disk discriminating device
Assignee	Sony Corporation
Assign./Filed	March 26, 1991/ Aug. 18, 1988
Inventors	Yoshida; Tadao, Fujiie; Kazuhiko, Ando; Ryo
Summary	Discriminating between recordable and pre-recorded discs.
Abstract	An objective lens (3) of an optical pick up head (10) is moved in a direction of the optical axis, and a signal level of the output detected by the optical pick up head (10) before and after a focussed state is compared with predetermined reference levels (Vref<SUB>1</SUB>) and (Vref<SUB>2</SUB>) level comparators (32) and (33), In order to discriminate the reproduction-only disk from the recording disk by utilizing a difference in the reflection factor on the recording surface on the optical disk (20). Operation of the optical disk recording/reproducing apparatus is automatically switched over depending upon the kind of the optical disk.