Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1998-04-03
2001-02-13
Hindi, Nabil (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S053130, C369S121000
Reexamination Certificate
active
06188653
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical data recording and reproducing apparatus and a method thereof, and an optical storage medium, such as a CD (Compact Disc) and DVD (Digital Video Disc, Digital Versatile Disc) for storing data which are recorded and reproduced by the apparatus and method.
Phase-change recording to record signals on optical storage media such as PDs and DVD-RAMs employs a laser beam that is irradiated on each optical storage medium to change a state of a recording layer of the optical storage medium from an amorphous state to a crystalline state and vise-versa.
Such phase-change recording type optical storage media are in the amorphous state just after layer formation. The amorphous state exhibits a low reflectivity as shown in FIG.
1
and hence a problem lies in picking up the laser beam reflected from the recording layer.
In order to solve the problem, a laser beam is irradiated on the optical storage media to raise a temperature of the recording layer to a temperature Tx at which the recording layer is in the crystalline state. The irradiation changes the recording layer from the amorphous state to the crystalline state that exhibits a high reflectivity as shown in
FIG. 1
with no difficulty in picking up the reflected laser beam.
The laser beam is again irradiated on the optical storage media to raise a temperature of the recording laser higher than a temperature Tmp at which the recording layer is in the amorphous state. The irradiation changes the recording layer from the crystalline state to the amorphous state.
As described above, the laser beam is controlled in signal recording so that it exhibits a bottom power to raise the temperature of the recording layer high than the temperature Tx and a peak power to raise the temperature of the recording layer higher than the temperature Tmp.
FIG. 2
illustrates a recording layer of a phase-change recording type optical storage medium D with pits P in the amorphous state while the other portions C in the crystalline state. This amorphous-crystalline state combination enables new signal over-writing on the storage medium D on which other signals have already been recorded.
Reproduction of the recorded signals is done by controlling the laser beam to decrease the temperature of the recording layer lower than the temperature Tx, the laser beam being irradiated on the recording layer and reflected therefrom.
The phase-change recording type rewritable optical storage media with large storage capacity as described above are highly applicable to data communications via optical fibers of high transfer rate and satellites, for example.
Such optical storage media are particularly applicable, for instance, to pay-per-view type video-on-demand service. Under the service, data, for example, containing many movies are compressed and transferred to users and recorded on the user's optical storage medium. Each user pay fees only for the movies they have watched among the recorded many movies.
However, under such service, a software such as a movie that has expired the term for use should be erased from the user's optical storage medium in order to protect copyright of the software.
SUMMARY OF THE INVENTION
A purpose of the present invention is to provide an optical data recording and reproducing apparatus and a method thereof capable of erasing signals while reproducing the signals from an optical storage medium.
Another purpose of the present invention is to provide an optical storage medium on and from which signals are recorded and reproduced by the apparatus and method.
The present invention provides an optical data processing apparatus comprising: an optical pick-up to selectively generate and irradiate a first laser beam and a second laser beam on an optical storage medium having a recording layer on which main data has been recorded, the main data including data to be reproduced and reproduction management data, the laser beam selection being made according to the reproduction management data, the first laser beam having a first laser power capable of carrying (reproducing) the main data without erasing when reflected from the optical storage medium and the second laser beam having a second laser power capable of erasing the main data from the optical storage medium while carrying (reproducing) the main data when reflected from the optical storage medium; and a reproducer to reproduce the data to be reproduced carried by the first or the second laser beam.
Further, the present invention provides a method of data processing comprising the steps of: selectively generating a first laser beam and a second laser beam; irradiating the first or the second laser beam on an optical storage medium having a recording layer on which main data has been recorded, the main data including data to be reproduced and reproduction management data, the laser beam selection being made according to the reproduction management data, the first laser beam having a first laser power capable of carrying the main data without erasing when reflected from the optical storage medium and the second laser beam having a second laser power capable of erasing the main data from the optical storage medium while carrying the main data when reflected from the optical storage medium; and reproducing the data to be reproduced carried by the first or the second laser beam.
Further, the present invention provides an optical storage medium having a layer for storing main data including data to be reproduced and reproduction management data, in reproduction of the main data, a first laser beam or a second laser beam being irradiated on the optical storage medium according to the reproduction management data, the first laser beam having a first laser power capable of carrying the main data without erasing when reflected from the optical storage medium and the second laser beam having a second laser power capable of erasing the main data from the optical storage medium while carrying the main data when reflected from the optical storage medium.
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Eguchi Hideharu
Nagano Hirofumi
Hindi Nabil
Jacobson Price Holman & Stern PLLC
Victor Company of Japan Ltd.
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