Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
2000-08-29
2003-04-29
Edun, Muhammad (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S047360, C369S047500, C369S053110
Reexamination Certificate
active
06556524
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optimum-recording-speed determining method for determining whether or not a given recording speed to be used for optical disk recording achieves appropriate recording that permits reproduction of recorded information with minimized reading errors or which recording speed permits reproduction of recorded information with minimized reading errors, and a recording-speed setting method and optical disk recording method based on such an optimum-recording-speed determination.
Today, recording on writable optical disks, such as write-once optical disks like CD−R and DVD−R media and rewritable optical disks like DVD+RW and DVD−RW media, is performed at increased speeds relative to a normal (non-increased or one-time) reproducing speed, such as a double speed, quadruple speed and the like, with a view to reducing a necessary recording time.
For appropriate optical disk recording that permits subsequent reproduction of recorded information with minimized reading errors, it has been conventional to change the so-called “recording strategy” such as by adjusting a power level, irradiation time, irradiation timing, etc. of a recording laser light beam in accordance with a selected one of the recording speed increase ratios.
Recently, it has been found that as the recording speed increase ratio is raised, appropriate recording tends to become more difficult to achieve by just changing the recording strategy (e.g., adjusting the power level, irradiation time, irradiation timing, etc. of the recording laser light beam), even with a same type of media (optical disks), depending on the manufacturer of the media, and thus there would be manufactured media prone to frequently cause reading errors. Consequently, it has been found that even recording speeds, settable in a recording drive (i.e., optical disk recording apparatus), have to be properly restricted depending on the media used.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide an optimum-recording-speed determining method for determining whether or not a recording speed to be used for optical disk recording achieves appropriate recording that permits reproduction of recorded information with minimized reading errors or which recording speed permits reproduction of recorded information with minimized reading errors, and an improved recording-speed setting method and optical disk recording method based on such an optimum-recording-speed determination.
According to an aspect of the present invention, there is provided a method of determining an optimum recording speed of an optical disk, which comprises the steps of: performing test recording on the optical disk at a given recording speed while changing a recording laser power level, and reproducing results of the test recording from the optical disk; measuring parameter values pertaining to reproduced signal quality on the basis of the reproduced results; and determining, on the basis of the parameter values, whether there is achieved any laser power level that can provide reproduced signal quality falling within a predetermined acceptable range, When it is determined that there is achieved the laser power level that can provide reproduced signal quality falling within the predetermined acceptable range, the given recording speed is judged as a proper recording speed, while when it is determined that there is achieved no laser power level that can provide reproduced signal quality falling within the predetermined acceptable range, the given recording speed is judged as an improper recording speed. With such arrangements, a determination can be made as to whether or not the recording speed to be used provides for appropriate recording that permits reproduction of recorded information with minimized reading errors.
According to another aspect of the present invention, there is provided a method of determining an optimum recording speed of an optical disk, which comprises the steps of: performing test recording on the optical disk while changing a recording speed and a recording laser power level, and reproducing results of the test recording from the optical disk; measuring parameter values pertaining to reproduced signal quality on the basis of the reproduced results; and determining, on the basis of the parameter values, whether there is achieved any laser power level that can provide reproduced signal quality falling within a predetermined acceptable range. Recording speed achieving the laser power level that can provide reproduced signal quality falling within the predetermined acceptable range is judged as a proper recording speed, while another recording speed achieving no laser power level that can provide reproduced signal quality falling within the predetermined acceptable range is judged as an improper recording speed.
The above-mentioned parameter values pertaining to reproduced signal quality may include at least parameter values relating to the total number of synchronization signals detected within a predetermined time period and a ratio between top and bottom peaks of a reproduced HF signal. Here, a recording speed achieving a laser power level that allows both of the parameter values relating to the total number of detected synchronization signals and the ratio between top and bottom peaks to fall within respective acceptable ranges may be judged as a proper recording speed. Results of the judgement may be displayed visually. Even at a recording speed which allows the optical disk recording apparatus to perform appropriate recording that permits reproduction of recorded information with minimized reading errors, a buffer memory within the recording apparatus, during actual recording, would cause a buffer underrun condition, i.e., run out of data, if a host computer, such as a personal computer, has low processing capabilities and can only transmit recording data at a low rate, with the result that the optical disk recording apparatus fails in the recording. To avoid such inconveniences, it is preferred that the optimum recording-speed determining method of the invention further comprise the steps of: causing the recording data to be transferred from a host computer to an optical disk recording apparatus so that the optical disk recording apparatus records the recording data onto the optical disk with a reproducing laser power level while changing the recording speed within a recording speed range settable in the optical disk recording apparatus; determining whether the buffer memory of the optical disk recording apparatus will cause buffer underrun during recording of the recording data, to thereby identify one or more recording speeds that can avoid the buffer underrun; and then performing the test recording by use of one of the recording speeds that can avoid the buffer underrun.
According to still another aspect of the present invention, there is provided a method of setting a recording speed of an optical disk, in which one or more recording speeds judged as proper through any one of the above-described speed determining methods is displayed in such a manner that one of the displayed recording speeds can be set for use in actual recording on the basis of a speed designating operation by a user.
According to still another aspect of the present invention, there is provided a method of setting a recording speed of an optical disk, in which one or more recording speeds judged as proper through any one of the speed determining methods is stored onto a predetermined area of the optical disk, and in which as the optical disk is re-loaded into the optical disk recording apparatus, information indicative of the recording speeds judged as proper is read out from the predetermined area and displayed in such a manner that one of the displayed recording speeds can be set for use in actual recording on the basis of a speed designating operation by a user without a need for performing the test recording again. Thus, for an optical disk for which the
Edun Muhammad
Pillsbury & Winthrop LLP
Yamaha Corporation
LandOfFree
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