Optical disk recording method and apparatus using alternative strategies of laser beam control

An optical disk recording method of recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the method comprising the steps of:

• providing a plurality of strategies which are selectable according to a model of the optical disk, the recording rate and the linear velocity for adjusting a pulse width of the laser drive signal and a power of the laser beam to form the pit;
• providing a first strategy and a second strategy for the same model of the optical disk, the same recording rate and the same linear velocity, the first strategy being designed to shorten the pulse width of the laser drive signal and increase the power of the laser beam as compared to the second strategy, the second strategy being designed to lengthen the pulse width of the laser drive signal and decrease the power of the laser beam as compared to the first strategy;
• and
• using changeably both of the first strategy and the second strategy dependently on conditions of the recording of information.

An optical disk recording method of recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the method comprising the steps of:

• providing a plurality of strategies which are selectable according to a model of the optical disk, the recording rate and the linear velocity for adjusting a pulse width of the laser drive signal to form the pit;
• specifying a target asymmetry value of a signal reproduced from the optical disk for each strategy;
• providing a first strategy and a second strategy for the same model of the optical disk, the same recording rate and the same linear velocity, the first strategy being designed to shorten the pulse width of the laser drive signal as compared to the second strategy, the second strategy being designed to lengthen the pulse width of the laser drive signal as compared to the first strategy;
• using changeably both of the first strategy and the second strategy in actual recording of information;
• performing test-recording of information on a part of the optical disk before the actual recording while sequentially changing the power of the laser beam under the strategy to be used;
• reproducing a signal from the part of the optical disk to find and set an initial power of the laser beam capable of obtaining the target asymmetry value specified for the strategy to be used;
• and
• performing the actual recording with the set initial power.

An optical disk recording method of recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk of CD recordable type moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the method comprising the steps of:

• providing a plurality of strategies which are selectable according to a model of the optical disk, the recording rate and the linear velocity for adjusting a pulse width of the laser drive signal and a power of the laser beam to form the pit, the strategies being represented by a formula (n+K)T concerning the pulse width of the laser drive signal where T is a time equivalent to a unit pit length, n is a multiplier of a length of the pit to be formed relative to the unit pit length, and K is a correction amount for the pulse width;
• providing a first strategy and a second strategy for the same model of the optical disk, the same recording rate and the same linear velocity, the first strategy being designed to set the correction amount K of the formula (n+K)T to shorten the pulse width of the laser drive signal as compared to the second strategy and to set the power of the laser beam to a level capable of obtaining an optimal asymmetry value of a signal reproduced from the optical disk, thereby decreasing jitters of the recorded information as compared to the second strategy, the second strategy being designed to set the correction amount K of the formula (n+K)T to lengthen the pulse width of the laser drive signal relative to the first strategy and to set the power of the laser beam to a level capable of obtaining an optimal asymmetry value of the reproduced signal, thereby decreasing crosstalk of the recorded information as compared to the first strategy;
• and
• using changeably both of the first strategy and the second strategy dependently on conditions of the recording of information.

An optical disk recording method of recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk of CD recordable type moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the method comprising the steps of:

• providing a plurality of strategies which are selectable according to a model of the optical disk, the recording rate and the linear velocity for adjusting a pulse width of the laser drive signal and a power of the laser beam to form the pit, the strategies being represented by a formula (n+K)T concerning the pulse width of he laser drive signal where T is a time equivalent to a unit pit length, n is a multiplier of a length of the pit to be formed relative to the unit pit length, and K is a correction amount for the pulse width;
• providing a first strategy and a second strategy for the same model of the optical disk, the same recording rate and the same linear velocity, the first strategy being designed to set the correction amount K of the formula (n+K)T to shorten the pulse width of the laser drive signal and increase the power of the laser beam as compared to the second strategy, the second strategy being designed to set the correction amount K of the formula (n+K)T to lengthen the pulse width of the laser drive signal and decrease the power of the laser beam as compared to the first strategy;
• and
• using changeably both of the first strategy and the second strategy dependently on conditions of the recording of information.

An optical disk recording method of recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk of CD recordable type moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the method comprising the steps of:

• providing a plurality of strategies which are selectable according to a model of the optical disk, the recording rate and the linear velocity for adjusting a pulse width of the laser drive signal to form the pit, the strategies being represented by a formula (n+K)T where T is a time equivalent to a unit pit length, n is a multiplier of a length of the pit to be formed relative to the unit pit length, and K is a correction amount for the pulse width;
• specifying a target asymmetry value of a signal reproduced from the optical disk for each strategy;
• providing a first strategy and a second strategy for the same model of the optical disk, the same recording rate and the same linear velocity, the first strategy setting the correction amount K of the formula (n+K)T to shorten the pulse width of the laser drive signal as compared to the second strategy, the second strategy setting the correction amount K of the formula (n+K)T to lengthen the pulse width of the laser drive signal as compared to the first strategy;
• using changeably both of the first strategy and the second strategy in actual recording of information;
• performing test-recording of information on a part of the optical disk before the actual recording while sequentially changing the power of the laser beam under the strategy to be used;
• reproducing a signal from the part of the optical disk to find and set an initial power of the laser beam capable of obtaining the target asymmetry value specified for the strategy to be used;
• and
• performing the actual recording with the set initial power.

An optical disk recording apparatus for recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the apparatus comprising:

• a strategy storage section that stores a plurality of strategies which are selectable according to a model of the optical disk and the recording rate for adjusting a pulse width of the laser drive signal and a power of the laser beam to form the pit, the strategies being provided in a first strategy version and a second strategy version for the same model of the optical disk and the same recording rate at the same linear velocity, the first strategy version being designed to shorten the pulse width of the laser drive signal as compared to the second strategy version and to set the power of the laser beam to a level capable of obtaining an optimal asymmetry value of a signal reproduced from the optical disk, thereby decreasing jitters of the recorded information as compared to the second strategy version, the second strategy version being designed to lengthen the pulse width of the laser drive signal as compared to the first strategy version and to set the power of the laser beam to a level capable of obtaining an optimal asymmetry value of the reproduced signal, thereby decreasing crosstalk of the recorded information as compared to the first strategy version;
• a disk model identification information detector section that detects disk model identification information for identifying the model of the optical disk to be recorded with the information;
• a recording rate setting section that sets the recording rate;
• a recording mode setting section that specifies one of the first strategy version and the second strategy version to be used for recording of information;
• a strategy selector section that selects a corresponding strategy from the strategy storage section according to the disk model identification information detected by the disk model identification information detector section and the recording rate specified by the recording rate setting section;
• a laser drive signal correction section that corrects the pulse width of the laser drive signal;
• a laser generator section having an optical head for generating the laser beam in response to the laser drive signal with the power capable of obtaining the optimal asymmetry value of the reproduced signal;
• and
• a control section that controls the laser drive signal correction section in accordance with the specified one of the first or second strategy version of the corresponding strategy selected by the strategy selector section to correct the pulse width of the laser drive signal and that controls the laser generator section to set the power of the laser beam to the level capable of obtaining the optimal asymmetry of the reproduced signal in accordance with the specified one of the first or second strategy version of the corresponding strategy.

An optical disk recording apparatus for recording information at a given recording rate by irradiating a laser beam modulated by a laser drive signal onto a surface of an optical disk moving at a given linear velocity relative to the laser beam, the information being recorded in the form of an alternate arrangement of pits and lands according to a mark length recording scheme, the apparatus comprising:

• a strategy storage section that stores a plurality of strategies which are selectable according to a model of the optical disk and the recording rate for adjusting a pulse width of the laser drive signal and a power of the laser beam to form the pit, the strategies being provided in a first strategy version and a second strategy version for the same model of the optical disk and the same recording rate at the same linear velocity, the first strategy version being designed to shorten the pulse width of the laser drive signal as compared to the second strategy version, the second strategy version being designed to lengthen the pulse width of the laser drive signal as compared to the first strategy version;
• a disk model identification information detector section that detects disk model identification information for identifying the model of the optical disk to be recorded with the information;
• a recording rate setting section that sets the recording rate;
• a recording mode setting section that specifies one of the first strategy version and the second strategy version to be used for recording of the information;
• a strategy selector section that selects a strategy from the strategy storage section according to the disk model identification information detected by the disk model identification information detector section and the recording rate specified by the recording rate setting section;
• a laser drive signal correction section that corrects the pulse width of the laser drive signal;
• a laser generator section having an optical head for generating the laser beam having a power modulated in response to the laser drive signal;
• an asymmetry value detector section that detects an asymmetry value of a signal reproduced from the optical disk;
• a control section that performs test-recording of information on a part of the optical disk before actual recording while sequentially changing the power of the laser beam under the selected strategy and determines an initial power of the laser beam capable of obtaining a target asymmetry value specified for the selected strategy according to the detected asymmetry value of the signal reproduced from the part of the optical disk, and further the control section controls the laser drive signal correction section in accordance with the specified one of the first or second strategy version of the selected strategy to correct the pulse width of the laser drive signal and controls the laser generator section to set the initial power of the laser beam capable of obtaining the optimal asymmetry of the reproduced signal in the actual recording of the information.