Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1999-07-26
2001-09-18
Tran, Thang V. (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S116000, C369S053150, C369S047530, C369S047500
Reexamination Certificate
active
06292448
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an information record medium for automatically determining a record power with respect to the information record medium such as an optical disc, and recording the information thereon.
2. Description of the Related Art
There is a write once (WO: Write Once) type optical disc, in which information can be written to the same location only once by using a condition change of organic pigment, as an optical record medium capable of postscript-writing.
For example, triphenyl-methane type pigment, fluoran type pigment, cyanine type pigment or the like is used as a record material, in the write once type optical disc using the organic pigment for the record film. By using those record materials, a pit is formed by the rear flow mechanism in which a vapor pressure in the vicinity of the surface of a record portion made from the record material is increased by the radiation of a light beam and the like, and this vapor pressure causes a fused portion to be peripherally expanded, which can correspond to “1” or “0” of digital data.
By the way, in the optical disc using the organic type pigment, a temperature at which the above-mentioned rear flow is induced is different depending on the record material. Thus, a power (electric power) of the light beam irradiated to form the pit is different for each kind of optical disc.
Therefore, in order to record the information onto the optical disc using the organic type pigment, a laser power optimal for the optical disc of each kind is encoded and recorded on a part of the optical disc, for example, a control track or a lead in area.
However, even if the same record material is used, the performance may be slightly different for each individual disc, in many cases. For this reason, the optimal laser power may not be irradiated onto the individual optical disc, if the laser power is uniformly applied for each kind of the optical disc.
That is, if the laser power is uniformly applied to the same type of optical disc as in the conventional technique, the influence resulting from the change of ambient environment, the change of record/reproduction performance for each optical disc or the like leads to a trouble that the information cannot be stably recorded.
So, a calibration of the laser power may be carried out prior to the actual start of the recording operation. In this calibration, a test signal is recorded on a test record region, which is prepared on the optical disc, by gradually changing the laser power, and the recorded test signal is reproduced. Then, the information is actually recorded at a record power which is obtained by the calibration to be optimal for the combination of a recorder and a record medium.
However, the record medium may have a defect caused by crack, dust and the like. The existence of such a defect on a location to which the test signal is written results in a problem that the signal quality of a record signal (i.e. the test signal) cannot be checked correctly.
In short, even if the test signal is recorded at the record power which is supposed to be optimal, when the defect is present on the recorded location, the reproduction signal for the test signal is not admitted to be the optimal signal. Thus, the record power used to record this test signal is not set as the optimal record power. On the contrary, although the test signal is not recorded at the optimal record power, the defect may cause the reproduction signal for this test signal to be admitted to be the optimal signal, and also cause a non-optimal record power to be erroneously set as the optimal record power. As a result, even if such a calibration has been performed, there may be a case where the information is not actually recorded at the record power optimal for the combination of the recorder and the record medium.
On the other hand, the recording operation with the optimal record power may not be performed not only in a case that the defect is present at the record position but also in a case that an abnormal condition in the servo system e.g., an external disturbance is generated at the time of recording.
SUMMARY OF THE INVENTION
The present invention is proposed in view of the above mentioned problems. It is therefore an object of the present invention to provide an information recording apparatus, which can set an optimal record power irrespectively of the presence or absence of a detect in a test record region of an information record medium, and also in a case that the external disturbance is generated.
The above object of the present invention can be achieved by a first information recording apparatus, in which before information is recorded onto an information record medium by irradiating a light beam, a test signal is recorded for each of a plurality of unit test record regions forming a test record region on the information record medium, with a plurality of different record powers, and then the test signal recorded in each of the unit test record regions is reproduced, and further an optimal record power for the light beam is selected on the basis of a condition of the reproduced test signal. The first information recording apparatus is provided with: a re-writable memory device for storing power set values to obtain the plurality of different record powers respectively, in response to location information which identifies respective one of the unit test record regions; a recording device for recording the test signal in the test record region on the basis of a constant record clock signal; a location information generating device for generating the location information at a cycle corresponding to a record time for each of the unit test record regions; a record controlling device for reading out the power set value stored in the re-writable memory device in accordance with the generated location information and then outputting the read out power set value to the recording device; a defect detecting device for detecting a defect in respective one of the unit test record regions, in which a recording operation is performed by the recording device; and a power set value storing device for storing the power set value, which is read out in accordance with one location information by the record controlling device when the defect is detected, into the re-writable memory device such that the stored power set value corresponds to another location information different from the one location information.
According to the first information recording apparatus, at first the location information identifying the respective one of the unit test record regions is generated at a cycle corresponding to a record time for each of the unit test record regions by the location information generating device. Then, the power set value stored in the re-writable memory device is read out by the record controlling device in accordance with the generated location information, and is outputted to the recording device. Then, the test signal is recorded by the recording device on the basis of a constant record clock signal, with the record power based on the power set value for each of the unit test record regions, which is identified by the location information in the test record region prepared on the information record medium. Since the power set value is set so that the record power different for each of the unit test record regions can be obtained, by reproducing the test signal for each of the unit test record regions after recording the test signal in the above mentioned manner, it is possible to evaluate the reproduction conditions of the test signals in accordance with the respective record powers, so that the optimal record power of the light beam can be selected on the basis of this evaluation. Further, when the defect in the unit test record region in which the recording operation is performed is detected by the defect detecting device, the power set value read out by the record controlling device on the basis of one location information which identifies the unit test record region
Shimoda Yoshitaka
Yoshida Masayoshi
Pioneer Corporation
Pitney Hardin Kipp & Szuch LLP
Tran Thang V.
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