Dynamic information storage or retrieval – Storage medium structure – Optical track structure
Reexamination Certificate
1998-11-24
2001-05-15
Dinh, Tan (Department: 2651)
Dynamic information storage or retrieval
Storage medium structure
Optical track structure
Reexamination Certificate
active
06233219
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording medium to/from which data can be recorded and reproduced, and a reproducing apparatus therefor.
2. Description of the Related Art
Magneto-optical recording media have been recently known as recording media to/from which data can be recorded and reproduced at high density, and in such a medium, tracks of lands and grooves are formed. Data is recorded and reproduced to/from the lands and grooves.
Address information is recorded as wobbles at a sidewall of a groove in an address region rather than a usual magneto-optical signal, and a data region is formed adjacent to the address region in the magneto-optical recording medium. In the data region, clocking wobbles different from the wobbles formed according to the address information are formed at one or both sidewalls of the groove. The clocking wobbles formed in the data region are reproduced, and a synchronizing signal for recording or reproducing a data signal is generated from thus reproduced wobble signal.
Since data is reproduced from a magneto-optical recording medium conventionally by irradiating the medium with three beams, and if address information is recorded by wobbling a sidewall of a groove in the magneto-optical recording medium, the address information corresponding to data recorded or to be recorded at the groove may be recorded but address information corresponding to data recorded or to be recorded at a land is not available by reproducing data from the land, because the waveforms of wobbles formed at both sidewalls of the land are different from each other.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a recording medium from which address information can be reproduced both at a land and a groove, and a reproducing apparatus therefor.
The object of the invention is achieved by providing a recording medium as follows: the recording medium includes a substrate having a main surface, the substrate includes a groove formed at the main surface and a land formed at the main surface and adjacent to the groove, and the land has first and second sidewalls wobbled according to the address of data recorded or to be recorded in the land.
Another object of the invention is achieved by providing a recording apparatus including first and second detectors provided in series in the tangential direction of a track for generating first and second detection signals, respectively based on detected reflected light, a subtracter for subtracting the second detection signal from the first detection signal, thereby generating a clock signal, third and fourth detectors provided in series in the tracking direction for generating third and fourth detection signals, respectively, according to detected reflected light, and an address information reproducing circuit for reproducing address information by performing addition/subtraction between the third and fourth detection signals.
An advantage of the present invention resides in that the address information may be accurately reproduced by irradiating a single beam of laser light.
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Copy of Japanese Patent Office Action for corresponding Japanese Patent Application No. 10-520301, including translation, mailed Aug. 29, 2000.
Hori Yoshihiro
Matsuyama Hisashi
Armstrong Westerman Hattori McLeland & Naughton LLP
Dinh Tan
Sanyo Electric Co,. Ltd.
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