Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-11-12
2001-10-30
Huber, Paul W. (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S047530
Reexamination Certificate
active
06310846
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a recording conditions controlling method for an optical memory device, for optimizing recording conditions, such as light quantity of a light beam or magnetic field strength of externally applied magnetic field, in an optical memory device which records information by projection of a light beam or application of an external magnetic field to an optical recording medium.
BACKGROUND OF THE INVENTION
Despite active research on high-density optical disks in recent years, there has still been a problem that high-density recording is difficult to be carried out due to the fact that uniform recording is prevented by the change in size of record marks as caused by a change in recording light quantity of a light beam projected on an optical disk or by a change in recording magnetic field strength of an externally applied magnetic field applied on a magneto-optical disk.
As a method for solving this problem, a control method of recording light quantity as disclosed in Japanese Unexamined Patent Publication No. 16965/1997 (Tokukaihei 9-16965) has been available. This method is adopted in a so-called light modulation recording device which records data by turning on or off a light beam, and optimizes the recording light quantity during the on state. The following will describe the above method referring to FIG.
12
.
First, in
FIG. 12
, record marks
102
are recorded on a track
101
. When the recording light quantity is increased, the record marks elongate, as indicated by the broken line. This changes a duty ratio, which is the ratio of a record mark
102
to a portion (non-record mark)
103
other than the record mark
102
. The change in duty ratio appears as a change in read signal so that a read signal
104
a
as indicated by the solid line is changed to a read signal
104
b
as indicated by the broken line. The change in duty ratio is detected with ease by detecting the DC components of these read signals. Further, when record marks are recorded beforehand by a plurality of different recording light quantities in a predetermined range, by searching a duty ratio of 1 to 1 from these record marks, it is possible to determine the optimum recording light quantity, which is the recording light quantity at which the duty ratio is 1 to 1.
However, when the control of recording light quantity is carried out on a disk with a small heat capacity by the described conventional method, a problem is presented that the optical disk is heated excessively by the maximum light quantity in a predetermined range of the recording light quantity and the optical disk is destroyed by the heat. The same problem is also presented when the environment temperature is high, whereby the optical disk is excessively heated by the maximum light quantity and the disk is destroyed by the heat.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a recording conditions controlling method for an optical memory device, for realizing stable recording conditions so as to prevent destruction of an optical recording medium by heat, which occurs when a heat capacity of the optical recording medium is small and/or when environment temperature is high.
In order to achieve the above-mentioned object, a recording conditions controlling method in accordance with the present invention (a) controls a reproducing condition in accordance with a reproducing signal read from a first mark of an optical recording medium so as to determine an optimum reproducing condition which minimizes an error rate of reproducing data; and (b) records a second mark by controlling a recording condition in accordance with the optimum reproducing condition and determines a recording condition which maximizes an amplitude of a reproducing signal from the second mark so as to record information on the optical recording medium in accordance with the recording condition thus determined.
In this method, the recording condition is controlled in two steps. First, the reproducing condition is controlled in accordance with the reproducing signal read from the first mark of the optical recording medium. By this control, the optimum reproducing condition which minimizes the error rate of reproducing data is determined. This optimum reproducing condition follows the heat capacity of the optical recording medium and/or with the environment temperature.
Then, the recording condition is controlled in accordance with the optimum reproducing condition thus determined, and the second mark is recorded. The recording condition which maximizes the amplitude of the reproducing signal from the second mark recorded is determined. This recording condition is determined in accordance with the optimum reproducing condition that follows the heat capacity of the optical recording medium and/or with the environment temperature, and therefore becomes the optimum recording condition. The information to be recorded is recorded on the optical recording medium in accordance with this optimum recording condition. As a result, it is possible to prevent destruction of the optical recording medium by heat when the heat capacity of the optical recording medium is small and/or when the environment temperature is high, thus realizing stable recording conditions.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5398227 (1995-03-01), Miyaoka et al.
patent: 5617400 (1997-04-01), Fuji
patent: 09016965 (1997-01-01), None
Angell David G.
Dike Bronstein Roberts & Cushman IP Group
Hartnell, III George W.
Huber Paul W.
Sharp Kabushiki Kaisha
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