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Patent Searching and Data


Title:
OPTICAL DISK AND OPTICAL DISK RECORDING AND REPRODUCING DEVICE
Document Type and Number:
Japanese Patent JPH07296416
Kind Code:
A
Abstract:

PURPOSE: To substantially increase the recording density of an optical disk without changing a laser wavelength and the numerical aperture of an objective lens by recording fresh information in land parts in addition to the information recorded as pits.

CONSTITUTION: The spectral rays respectively detected by photodetecting elements SE 11, SEM 1, SE 31, SEM 2, SEM 3 of a photodetector SE are used in the following manner: A focus error signal is formed in accordance with the output signal of the element SEM 1. A bit reproducing signal is formed in accordance with the sum of the output signals of the elements SEM 2, SEM 3. A change over as to whether the information is reproduced in accordance with the bit reproducing signal or the information is reproduced in accordance with a magneto-optical reproduction signal is controlled by a system controller. A tracking error signal is formed from the difference between the elements SE 11 and SE 31. The signal is required to be inverted its polarity according to the case the pit parts are reproduced and the case the land parts are recorded/reproduced.


Inventors:
WASHIMI SATOSHI
Application Number:
JP10605294A
Publication Date:
November 10, 1995
Filing Date:
April 20, 1994
Export Citation:
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Assignee:
SANYO ELECTRIC CO
International Classes:
G11B11/105; G11B7/00; G11B7/005; G11B7/09; G11B7/24035; G11B7/24085; G11B7/24091; G11B11/10; (IPC1-7): G11B7/24; G11B7/00; G11B7/09; G11B11/10
Attorney, Agent or Firm:
Maruyama Akio