WO2009119632A1 - Method of adjusting recording strategy - Google Patents

Abstract

An optical information recording/reproducing method comprises a step of reading predetermined information previously stored in an overwritable optical information recording medium, a step of selecting any information from among the predetermined information, another predetermined information previously stored in a device for recording/reproducing information on/from the medium, and information obtained by mixing the predetermined information and the other predetermined information and adjusting a recording strategy for recording on the optical information recording medium on the basis of the selected information, and a step of generating a recording signal on the basis of the adjusted recording strategy. The step of adjusting the strategy comprises a step of setting an initial value to each of plural parameters of the waveform of a pulse-train type strategy, a step of selecting first recording power on the basis of the initial value set to each of the plural parameters, a step of selecting reference erase power on the basis of the selected first recording power, a step of selecting reference recording power on the basis of the initial value set to each of the plural parameters, the selected first recording power, and the selected reference erase power, and a step of selecting the length of a reference cooling pulse on the basis of the initial value set to each of the plural parameters, the selected first recording power, the selected reference erase power, and the reference recording power.

Description

Recording strategy adjustment method

The present invention relates to a recording strategy adjusting method for recording information on an optical information recording medium, and an optical information recording / reproducing apparatus using the method, and in particular, there is an overwrite that integrally deletes and records information. The present invention relates to a recording strategy adjusting method for recording information on a possible optical information recording medium, and an optical information recording / reproducing apparatus using this method.

An optical disc device is a device that records information on an optical disc or reads recorded information using an optical head. In such an optical disc apparatus, there are several factors that influence the performance of the optical disc apparatus during recording or reproduction.

As for recording, the control of the amount of irradiation light that forms the recording mark is a very important factor. Control of the amount of irradiation light generally includes control of output levels such as recording power and bias power, and control of the pulse width and pulse position (time direction) of a laser pulse. In this technical area, both controls are collectively referred to as a recording strategy.

1A to 1E are waveform chart groups showing a plurality of examples in the recording strategy. 1A to 1E, the horizontal axis represents the passage of time, and the vertical axis represents the recording signal intensity. As shown in FIGS. 1A to 1E, there are various types of recording strategies, and the output level and pulse shape differ depending on the recording medium and recording speed. FIG. 1A is a waveform diagram showing an example of a pattern to be recorded in a recording strategy. FIG. 1B is a waveform diagram showing an example of a pulse train recording strategy for overwrite recording in the recording strategy. FIG. 1C is a waveform diagram showing an example of a pulse train type recording strategy for non-overwrite recording in the recording strategy. FIG. 1D is a waveform diagram showing an example of a simple rectangular recording strategy in the recording strategy. FIG. 1E is a waveform diagram showing an example of a partially emphasized rectangular recording strategy in the recording strategy.

In the case of HD DVD (High Definition DVD), the next-generation DVD that has begun to be shipped in recent years, the pulse train type recording strategy for both write-once HD DVD-R, rewritable HD DVD-RW and HD DVD-RAM. Is mainly used.

In an optical disc apparatus having such various strategies, usually, when a medium is loaded, the type of the disc, the name of the medium manufacturer, etc. are first read from the disc. Then, the recording power called OPC (Optimum Power Control) is adjusted by using a strategy corresponding to each medium and a recommended recording strategy embedded in the medium, which is calibrated by a typical apparatus in advance. The optical disc medium has an area for adjusting the recording power in a part of the disc, and only the adjustment of the recording power is appropriately performed in the area. As a method for adjusting the recording power, there are known a β method for obtaining a β value by inspecting asymmetry obtained from reproduction amplitudes of a long mark and a short mark, and a γ method for judging from the degree of saturation of the recording mark amplitude. In the conventional DVD-R, the β method is used, and in the overwritable DVD-RW and DVD + RW, the γ method is generally used. However, the method is not limited to this. The recording strategy is not regulated as appropriate, and only the information calibrated in advance or the information embedded in the disc can be relied upon.

Here, some performance indexes used in the optical disc will be described. FIG. 2 is a diagram illustrating an example of the β value calculation method described above. In the time chart of FIG. 2, the horizontal axis represents the passage of time, and the vertical axis represents the strength of the reproduction signal. As shown in FIG. 2, first, 11T peak level A and 11T bottom level B with respect to Ref are obtained from long marks and short marks, for example, 11T and 3T reproduction waveforms.
β = 0.5 × (AB) / (A + B) (1)
It is calculated from the following definition formula.

Ref is set at the center of the short mark playback amplitude. The above equation (1) means the difference between the center of the maximum amplitude and the center of the minimum amplitude using the signal level such as the minimum value, maximum value, and average level (average voltage) of each pattern. , Used synonymously with asymmetry. This index can be obtained by analog processing. However, even if digital processing is used, it can be calculated by capturing a desired signal from the reproduction signal.

Further, by utilizing the fact that the β value correlates with the jitter σ which is an evaluation index of the recording signal quality and the number of errors, it can be determined that the device can be used when the β value is within a certain range. Therefore, the β value itself does not guarantee performance. If the correspondence between the β value and an absolute value index of performance, for example, the number of errors, error rate, and jitter value, the value is meaningful. Therefore, the β value is mainly used as an adjustment target value. Since analog processing is possible, detection is possible even if the signal quality of the recorded pattern sequence is poor. This means that the dependence on the recorded state is low. Further, the β value is an index that can determine the direction in which the recorded signal is shifted, and is also an index that has polarity.

Here, the polarity of the β value also varies depending on the configuration of the circuit used and whether the reflectance of the recording part is higher or lower than the reflectance of the unrecorded part. However, in this specification, as the recording power increases, when the recorded mark becomes relatively longer than the space, the β value has a negative (minus) polarity, and conversely, the recording mark is relatively relative to the space. The β value when it becomes shorter is expressed as having a positive polarity. FIG. 3 shows an example of a time chart when the mark is relatively long with respect to the space as compared with FIG. In this case, for example, the changing direction of the β value changing as shown in FIGS. 2 to 3 is downward, and the value is negative.

Further, PRML (Partial Response Maximum Likelihood) detection is used for HD DVD, which is a next-generation DVD that is further densified. Since HD DVD cannot measure jitter itself, an index called PRSNR (Partial Response Signal to Noise Ratio) has been introduced. PRSNR is a signal quality evaluation index instead of jitter, and is an index adopted in HD DVD, and is an SNR (Signal to Noise Ratio) value in PRML detection. Further, the PRSNR can be converted into an error rate. The higher this value, the better the signal quality, and the opposite of jitter and error rate. Non-Patent Literature 1 (Japan Journal of Applied Physics Vol.43, No. 7B, 2004, pp. 4859-4862 “Signal-to-Noise Ratio in a PRML Detection”, S. OHKUBOet. Details of PRSNR are also disclosed, including conversion of.

As another method for evaluating the quality of the reproduced waveform, there is a method for directly obtaining the error rate and the number of error bytes. These are indexes indicating the absolute value of performance. However, in the case of a signal recorded in a state where the recording strategy is largely deviated, the extraction of the synchronous clock becomes severe, and it is difficult to use it universally under various conditions.

Next, since the recording strategy has a great influence on the recording / reproducing performance of the optical disc, many recording methods (recording strategies) and adjustment methods for recording strategies have been devised.

In relation to the above, Patent Document 1 (Japanese Patent Laid-Open No. 10-64064) discloses an invention relating to an optical disk recording method and an apparatus therefor.
Japanese Patent Application Laid-Open No. 2004-151867 has a description of adjusting erase power and bottom power other than write power. This is done by changing the write power first, and then changing the erase power and bottom power to perform test recording. After test recording, reproduce the data to determine whether the asymmetry value or the modulation depth becomes the target value. Alternatively, the optimum values of the writing power, the erasing power, and the bottom power at which the error rate is the lowest are obtained, and actual recording is performed using a combination of these optimum values.

Patent Document 2 (Japanese Patent Laid-Open No. 2000-90435) discloses an invention relating to a recording apparatus.
In Patent Document 2, the time of the final cooling pulse ECP and the time of the leading heating pulse SP in the continuous cooling pulse CP are determined according to the value of (center of amplitude of minimum recording mark) / (center of amplitude of maximum recording mark). A method is described in which the asymmetry of a mark after recording by a mark edge recording method on a phase change optical disk is corrected by correcting any one, two, or three of the multi-pulse duty.

Here, as a specific adjustment, the start pulse and the multi-pulse duty are adjusted so that the start heating pulse SP is 1T and the multi-pulse duty is 0.5T, and the width of the start heating pulse SP is increased by T / 4 or T There is a description that the strategy is changed so that the ratio of the center of amplitude becomes 1 by decreasing the duty of the multi-pulse at the time of T / 8 and decreasing the duty of the multi-pulse at the same time. This is an adjustment method in which the head heating pulse and the multi-pulse are simultaneously changed in a decreasing direction so that the amplitude center is always as close to 1 as possible.

Patent Document 3 (Japanese Patent Laid-Open No. 2003-85755) discloses an invention relating to a recording method for a phase change optical disc.
In Patent Document 3, trial recording is performed on a phase-change optical information recording medium by changing the heat duty and the recording power of the multi-pulse part of the recording strategy, and the β value of the reproduction RF signal in the trial recording area is obtained. The maximum value of the β value is acquired for each heat duty, and the heat duty that takes the largest value among the maximum values is described as the heat duty of the multi-pulse part, and the recording speed is the β value for the fluctuation of the recording power. The description of changing the fluctuation slope within the range of -5% / mW to 3% / mW and the recording power at the time of test recording is within ± 2% of the fluctuation of the β value relative to the fluctuation of the recording power. There are descriptions that vary within the range.

Patent Document 4 (Japanese Patent Application Laid-Open No. 2004-55115) discloses an invention relating to a recording method of an optical recording medium.
In Patent Document 4, recording is performed while changing the level of the cooling pulse in the recording pulse signal in the test recording based on the recording condition obtained from the disc, and the test recording data is reproduced to evaluate the reproduction signal waveform. There is a description of setting the cooling level at which the target asymmetry value is obtained as the optimum cooling level.

Patent Document 5 (Republished WO 2005/034109) discloses an invention relating to an information recording apparatus.
Patent Document 5 has a description relating to an information recording apparatus including a recording unit, a calculating unit, a measuring unit, and a correcting unit. Here, the recording means is for irradiating the information recording medium with a laser beam having a recording power corresponding to the set value to record the recording information on the information recording medium. The calculating means reproduces the test recording information recorded while changing the setting value in the recording means, thereby creating correlation information indicating the correlation between the setting value and the reproduction quality, and at the same time the target having the desired reproduction quality. This is for obtaining a reference set value for obtaining reproduction quality. The measuring means is for measuring the reproduction quality by reproducing the recorded information recorded using the reference set value in the recording means. When the reproduction quality measured by the measuring means is different from the target reproduction quality, the correction means obtains a correction amount of the reference set value based on the correlation information, and the corrected set value based on the correction amount is a new reference This is for correcting the reference set value so as to be the set value.

Patent Document 6 (Japanese Patent Application Laid-Open No. 2007-58939) discloses an invention relating to an optical disk device.
In Patent Document 6, the recording device compares the manufacturer and version information of the loaded recording medium, and if there is corresponding information, uses that information. If not, the recording light waveform, recording output, and recording light wavelength are used. Search for information on the recording method such as, if there is matching information, use that information, otherwise use the reference recording method or the recording method recorded on the recording medium to perform test recording and record There is a description of evaluating the quality and adjusting the recording waveform, recording power, and erasing power.

Patent Document 7 (Japanese Patent Laid-Open No. 2007-149238) discloses an invention relating to an optical disk device.
Patent Document 7 has a description relating to an optical disk apparatus that records or reproduces information by irradiating an optical disk with laser light. The optical disk apparatus includes a disk motor, a motor drive circuit, a laser diode, a laser drive circuit, a temperature detection unit, a β measurement unit, a recording power correction factor calculation unit, and a control unit. Here, the disk motor and the optical disk are driven to rotate. The motor drive circuit is for driving a disk motor. The laser diode is for emitting laser light. The laser drive circuit is for driving a laser diode. The temperature detecting means is for detecting the temperature of the laser diode or the vicinity thereof. The β measuring means is for measuring the β value of the recording mark recorded on the optical disc from the reproduction signal based on the reflected laser beam from the optical disc. The recording power correction factor calculation means calculates the difference between the preset target β value and the measured β value, calculates the recording power correction factor on the high power level side of the recording strategy according to the difference, and calculates This is for outputting the resulting signal to the laser drive circuit side. The control means is for controlling the motor drive circuit, the β measurement means, and the recording power correction factor calculation means. This optical disk apparatus, when the temperature of the laser diode or the vicinity thereof changes exceeding the reference value, temporarily stops the recording operation based on the output of the temperature detecting means, measures the β value of the recording mark by the β measuring means, and measures Based on the result, the recording power correction rate calculation means calculates the recording power correction rate on the high power level side of the recording strategy, and corrects the recording power on the high power level side of the recording strategy with the calculated correction rate.

Patent Document 8 (Japanese Patent Laid-Open No. 2007-149304) discloses an invention relating to an optical disc recording / reproducing apparatus.
Patent Document 8 describes an optical disc recording / reproducing apparatus that performs recording / reproduction using a laser beam having a set power with respect to a rewritable optical disc having multiple recording layers. The optical disk recording / reproducing apparatus includes a first setting recording unit, a DC erasing unit, a recording state detecting unit, a DC erasing power determining unit, an erasing power calculating unit, and a second setting recording unit. And a recording power determination means and a recording power calculation means. Here, the first setting recording means includes a recording power for changing the recording layer from the crystalline state to the amorphous state under predetermined recording conditions, an erasing power for changing the recording layer from the amorphous state to the crystalline state, and the recording layer. The bias power to prevent thermal diffusion during recording is set, and a test recording signal is recorded in a predetermined area of the optical disc by a laser beam in which the set recording power, erasing power and bias power are changed in a predetermined order. Is to do. The DC erasure unit is a DC erasure unit that erases the area of the optical disc on which the test recording signal is recorded by the first setting recording unit, with the power related to the set erasing power as a reference, and the level of the erasing power changes stepwise. This is for recording with a laser beam of only power. The recording state detection means reproduces the area of the optical disc on which the test recording signal is recorded, and modulates the reproduction signal, a γ value that is a parameter indicating the normalized slope characteristic of the modulation degree, and the asymmetry of the reproduction signal It is for detecting at least one of parameters (β value or asymmetry value) representing sex. The determination means for DC erasing power reproduces a plurality of areas having different erasing powers recorded by the DC erasing power by the DC erasing power, and the DC erasing power among the values detected by the recording state detecting means. This is for determining a detection value that matches a predetermined detection value or detection condition for power. The erasing power calculation means is for multiplying the DC erasing power value in the region where the detection value is matched by the DC erasing power determination means by a predetermined first coefficient to obtain an optimum erasing power level. Is. The second setting recording means changes the setting value of the erasing power in the first setting recording means to the erasing power value detected by the erasing power calculating means, and is different from the area recorded by the DC erasing means of the optical disc. This is for recording a test recording signal in the area by a laser beam with only the recording power varied. The recording power determining means reproduces the area recorded by the second setting recording means and determines whether the value detected by the recording state detecting means matches a predetermined detection value or detection condition for recording power. Is to do. This is for obtaining the optimum recording power level by multiplying the recording power value in the region where the detection value is coincident by the recording power determination means by a predetermined second coefficient. This optical disc recording / reproducing apparatus is characterized in that an optimum erasing power value and recording power value at the time of optical disc recording are derived.

Patent Document 9 (Japanese Patent Application Laid-Open No. 2007-157196) discloses an invention related to an optical disk device.
Patent Document 9 has a description relating to an optical disc apparatus for recording and reproducing data on an optical disc. This optical disc apparatus includes a signal forming circuit, an optical pickup, a detection circuit, and a control circuit. Here, the signal forming circuit is for generating the first test signal. The optical pickup records the first test signal by irradiating the optical disc with laser light based on the first test signal supplied from the signal forming circuit, and reproduces the first test signal from the optical disc. Is for. The detection circuit is for obtaining a β value indicating asymmetry from the first test signal reproduced by the optical pickup. The control circuit is for setting the optimum recording power Pwo from the recording power at which the β value acquired by the detection circuit becomes the target β value. The signal forming circuit generates, as the first test signal, a test signal in which the erasing power Pe is fixed and the recording power Pw is changed.

Patent Document 10 (Japanese Patent Laid-Open No. 2007-226916) discloses an invention relating to an optical recording / reproducing apparatus.
Japanese Patent Application Laid-Open No. 2003-228561 describes an optical recording / reproducing apparatus in which information is recorded by a front edge and a rear edge of a mark formed on a recording medium on which information is recorded by a laser. The optical recording / reproducing apparatus includes a recording pulse shift setting unit, a mark edge position evaluation unit, an assumption unit, a sensitivity calculation unit, and a write strategy calculation unit. Here, the recording pulse shift setting section determines the space between one mark and the immediately preceding space length between the other mark located immediately before the one mark and the other mark located immediately after the one mark. The write pulse write strategy is set by shifting the front and rear edges of the recording pulse, which is the recording waveform of the laser, in accordance with the space length. The mark edge position evaluation unit detects the front edge and the rear edge of the mark formed based on the write strategy, and detects the front mark edge position error, which is the position error of the mark front edge, and the rear edge position error, which is the position error of the mark rear edge. This is for detecting a mark edge position error. The assumption unit assumes that the front mark edge position error is represented by a first linear function having the shift amount of the front edge of the recording pulse and the shift amount of the rear edge of the recording pulse as variables, and the rear mark edge position. This is because it is assumed that the error is expressed by a second linear function having the shift amount of the front edge of the recording pulse and the shift amount of the rear edge of the recording pulse as variables. The sensitivity calculation unit performs test recording for each combination of the immediately preceding space length and the immediately following space length, and then performs first recording based on the front mark edge position error and the rear mark edge position error detected by the mark edge position evaluating unit. This is for calculating the sensitivity expressed by each proportional coefficient included in the linear function and the second linear function. The write strategy calculation unit is for calculating the write pulse write strategy based on the sensitivity.

* The recording strategy adjustment items have a wide range of parameters such as recording pulse width and multiple power levels. Accordingly, not only does it take a long time to optimize the parameters, but adjustment without a guide may not necessarily result in adjustment that brings out the desired performance. In addition, depending on the skill level of the coordinator, there is a problem that the effect of optimization varies.

On the other hand, in Patent Document 3, it is necessary to limit the recording speed in order to obtain the maximum value of β. When the absolute value of the fluctuation slope is defined, it is necessary to adjust another condition to the state. For this reason, it is not versatile and is not always a simple method.

As in Patent Document 2, even if the adjustment is performed without any policy, sufficient recording / reproducing performance cannot always be obtained. In particular, in the method in which the head heating pulse and the multi-pulse are simultaneously changed in a decreasing direction, when the combination of the initial pulse widths is bad, it is not always easy to draw out the best medium performance and the versatility is poor.

It is known that the erasing power affects the performance in the recording strategy. According to the method of Patent Document 1, the recording power is first determined. However, this recording power requires the optimum recording power at the erasing power used when determining the recording power, and may not always have a desired performance. Such a problem becomes a remarkable problem particularly in the case of a medium to be adjusted for the first time. Furthermore, the asymmetry values used for determining the recording power and the erasing power are the same value, and it is complicated to adjust the erasing power with respect to the erasing power at the time of determining the recording power. In addition, the waveform shape parameters used for recording are not mentioned at all, are unclear as a guideline, and it is difficult to obtain knowledge about a comprehensive adjustment method including a recording strategy.

Similarly, in Patent Document 4 and Patent Document 6, there are a large number of strategy parameters, each of which affects each other, so the combination and adjustment order are also important. Even if only the adjustment of one parameter of the recording strategy is known, there is no description on how to adjust various other recording parameters. Therefore, it is not always possible to make an adjustment that brings out the best recording performance.

In summary, there is no known general-purpose method that can adjust the strategy reliably and quickly in recording strategy adjustment for information recording on an overwritable information recording medium in which erasing and recording are performed integrally. .

Here, it is not impossible to execute combinations of all parameters, but it takes a lot of time to make adjustments using a suitable combination and a proper procedure without having an adjustment policy. It just costs In such a method, the adjustment cannot be performed quickly, and there is a high possibility of falling into the local optimum adjustment, and the recording strategy cannot always be adjusted reliably.

The present invention has been devised to solve the above problems. An object of the present invention is to provide a general-purpose method for quickly and surely adjusting a recording strategy used for recording information on an overwritable information recording medium in which erasing and recording are performed integrally. is there.

An optical information recording / reproducing method according to the present invention includes a step of reading predetermined information stored in advance on an overwritable optical information recording medium, a predetermined information, and an apparatus for recording / reproducing information on the medium. Recording for selecting any one of the predetermined information and the information obtained by mixing the predetermined information and the other predetermined information, and recording on the optical information recording medium based on the selected information Adjusting the strategy, and generating a recording signal based on the adjusted recording strategy. The step of adjusting the strategy is to set an initial value for each of the plurality of parameters in the waveform of the pulse train type strategy, and to select the first recording power based on the initial value set for each of the plurality of parameters. Selecting a reference erase power based on the selected first recording power, an initial value set for each of the plurality of parameters, a selected first recording power, and a selected reference erase A step of selecting a reference recording power based on the power, an initial value set for each of the plurality of parameters, a selected first recording power, a selected reference erasing power, and a reference recording power. And selecting a length of the reference cooling pulse based on. The step of setting an initial value for each of the plurality of parameters includes a step of setting a predetermined initial value of the recording pulse width as a width common to a plurality of recording pulses included in the waveform, and a predetermined width of the cooling pulse included in the waveform. A step of setting an initial value of the cooling pulse width, a step of setting a predetermined bottom power initial value as the value of the bottom power of the waveform, and a predetermined initial value of erasing power as the value of the erasing power of the waveform Step. The step of selecting the first recording power is a step of sequentially setting a plurality of values included in a predetermined range as a value of the first recording power, and each of the plurality of values is selected on the optical information recording medium. Based on the first recording power, the step of recording the signal, the step of reproducing the recorded signal from the optical information recording medium for each of the plurality of values, and the reproduced signal for each of the plurality of values And measuring an asymmetry value and selecting a most preferred first recording power value based on the measured asymmetry value. The most preferable criterion for selecting the first recording power value is that the absolute value of the asymmetry value corresponding to the first recording power value exceeds a predetermined value. The step of selecting the reference erasing power includes a step of sequentially setting a plurality of values included in a predetermined range as a value of the reference erasing power, and a reference set on the optical information recording medium for each of the plurality of values. A step of recording a signal with erasing power, a step of reproducing a recorded signal from the optical information recording medium for each of a plurality of values, and a plurality of values based on the reproduced signals for each of the values, Measuring an amplitude value and an asymmetry value; and selecting a most preferable reference erasure power value based on the measured amplitude value and the asymmetry value. The criterion for selecting the most preferable reference erasing power value is a value lower than the erasing power in the vicinity where the decrease rate of the amplitude value reaches the maximum value, and the polarity of the asymmetry value is the result of the first recording power selection step. It is the same and the absolute value of the asymmetry value is minimized.

An optical information recording / reproducing apparatus according to the present invention includes a reproduction signal reading circuit unit, a recording strategy adjustment unit, and a recording signal generation circuit unit. Here, the reproduction signal reading circuit unit reads predetermined information stored in advance on an overwritable optical information recording medium. The recording strategy adjustment unit selects one of the predetermined information, another predetermined information held in advance by itself, and information obtained by mixing the predetermined information and another predetermined information, and selects the selected information. Based on the above, the recording strategy for recording on the optical information recording medium is adjusted. The recording signal generation circuit unit generates a recording signal based on the recording strategy adjusted by the recording strategy adjustment unit. The recording strategy adjustment unit includes a pulse train waveform parameter setting unit, a first recording power selection unit, a reference erase power selection unit, a reference recording power selection unit, and a reference cooling pulse selection unit. Here, the pulse train waveform parameter setting unit sets an initial value for each of a plurality of parameters in the waveform of the pulse train type strategy. The first recording power selection unit selects the first recording power based on the initial values set for each of the plurality of parameters. The reference erasing power selection unit selects the reference erasing power based on the selected first recording power. The reference recording power selection unit selects the reference recording power based on the initial value set for each of the plurality of parameters, the selected first recording power, and the selected reference erasing power. The reference cooling pulse selection unit determines the length of the reference cooling pulse based on the initial value set for each of the plurality of parameters, the selected first recording power, the selected reference erasing power, and the reference recording power. It is to select the size. The initial value set for each of the plurality of parameters in the waveform of the pulse train type strategy includes a predetermined recording pulse width initial value set as a width common to the plurality of recording pulses included in the waveform, and a cooling pulse included in the waveform. A predetermined cooling pulse width initial value set as the width, a predetermined bottom power initial value set as the value of the bottom power of the waveform, and a predetermined erase power initial value set as the value of the erasing power of the waveform It comprises. The first recording power selection unit includes a first setting unit, a first recording unit, a first reproduction unit, a first measurement unit, and a first selection unit. The first setting unit sequentially sets a plurality of values included in a predetermined range as the value of the first recording power. The first recording unit records signals for each of the plurality of values on the optical information recording medium with the first recording power set by the first setting unit. The first reproduction unit reproduces the signal recorded by the first recording unit from each of the plurality of values from the optical information recording medium. The first measuring unit measures an asymmetry value for each of the plurality of values based on the signal reproduced by the first reproducing unit. The first selection unit selects the most preferable first recording power value based on the asymmetry value measured by the first measurement unit. The most preferable criterion for selecting the first recording power value is that the absolute value of the asymmetry value corresponding to the first recording power value exceeds a predetermined value. The reference erasing power selecting unit includes a second setting unit, a second recording unit, a second reproducing unit, and a second measuring unit. The second setting unit sequentially sets a plurality of values included in a predetermined range as the reference erasing power value. The second recording unit records signals for each of the plurality of values on the optical information recording medium with the reference erasing power set by the second setting unit. The second reproducing unit reproduces the signal recorded by the second recording unit for each of the plurality of values from the optical information recording medium. The second measurement unit measures an amplitude value and an asymmetry value for each of the plurality of values based on the signal reproduced by the second reproduction unit. The second selection unit selects the most preferable reference erasing power value based on the amplitude value measured by the second measurement unit and the asymmetry value. The criterion for selecting the most preferable reference erasing power value is a value lower than the erasing power in the vicinity where the decrease rate of the amplitude value reaches the maximum value, and the polarity of the asymmetry value is the result of the first recording power selection step. It is the same and the absolute value of the asymmetry value is minimized.

The objects, effects, and features of the above invention will become more apparent from the description of the embodiments in conjunction with the accompanying drawings.

FIG. 1A is a waveform diagram showing an example of a pattern to be recorded in a recording strategy. FIG. 1B is a waveform diagram showing an example of a pulse train recording strategy for overwrite recording in the recording strategy. FIG. 1C is a waveform diagram showing an example of a pulse train type recording strategy for non-overwrite recording in the recording strategy. FIG. 1D is a waveform diagram showing an example of a simple rectangular recording strategy in the recording strategy. FIG. 1E is a waveform diagram showing an example of a partially emphasized rectangular recording strategy in the recording strategy. FIG. 2 is a diagram for explaining the definition of the β value. FIG. 3 is a diagram illustrating an example in which the mark is relatively long with respect to the space as compared with FIG. 2. FIG. 4 is a block diagram for explaining the outline of the information recording / reproducing apparatus according to the first embodiment of the present invention. FIG. 5 is a block diagram for explaining the outline of the system controller in the information recording / reproducing apparatus according to the first embodiment of the present invention. FIG. 6 is a schematic block diagram of the RF circuit unit used in the example of the first embodiment of the present invention. FIG. 7 is a flowchart of a recording strategy adjustment method according to this embodiment. FIG. 8A is a waveform diagram for explaining a 5T mark to be recorded in the pulse train type recording strategy according to the present invention. FIG. 8B is a waveform diagram illustrating a pulse train waveform at a 5T mark of the pulse train type recording strategy according to the present invention. FIG. 9 is a graph showing an example of the relationship between the maximum amplitude value Vpp of the reproduction signal and the asymmetry β value when the recording power Pp is changed under the condition that the erasing power is not substantially applied to the area where the recording mark is not formed. It is. FIG. 10 is a graph showing an example of the relationship between the maximum amplitude Vpp of the reproduction signal and the asymmetry β value when the erasing power Pe is increased with the recording power as the first recording power. FIG. 11 is a diagram showing an example in which the amplitude does not show a saturation tendency even when the recording power is increased. FIG. 12 is a diagram showing an example of a change in the asymmetry value β when the recording power Pp is lowered with the erasing power as the reference erasing power. FIG. 13 shows the parameter set No. It is a table | surface which shows 1, 2, 3, 4. FIG. 14 is a graph showing an example of the relationship of the best PRSNR value in each parameter set in a certain parameter set. FIG. 15 is a block diagram for explaining the configuration of the recording strategy adjuster when it is implemented by a computer. FIG. 16 is a block diagram for explaining each function when the system controller is implemented by a computer.

Hereinafter, a recording strategy adjusting method and an optical information recording / reproducing apparatus according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 4 is a block diagram for explaining the outline of the information recording / reproducing apparatus according to the first embodiment of the present invention. The information recording / reproducing apparatus according to the present embodiment includes a spindle drive system 12, an optical head 13, a servo controller 14, an LD (Laser Diode, laser diode) driver 15, a modulator 16, and an RF (Radio Frequency) circuit unit. 17, a demodulator 18, and a system controller 19.

The optical head 13 includes an objective lens 21, a beam splitter 22, a laser diode 23, a photodetector 24, and a preamplifier 25.

FIG. 5 is a block diagram for explaining the outline of the system controller 19 in the information recording / reproducing apparatus according to the first embodiment of the present invention. The system controller 19 includes a recording strategy adjuster 26 and a CPU 27.

The spindle drive system 12 is physically connected to the optical disk 11. On the other hand, the spindle drive system 12 is electrically connected to the system controller 19. In addition, the system controller 19 is connected to the servo controller 14, the LD driver 15, and the modulator 16. On the other hand, the servo controller 14 is electrically connected to the objective lens 21. On the other hand, the objective lens 21 is optically connected to the optical disc 11. On the other hand, the modulator 16 is electrically connected to the LD driver 15. On the other hand, the LD driver 15 is electrically connected to the laser diode 23. On the other hand, the laser diode 23 is optically connected to the beam splitter 22. In addition, the beam splitter 22 is optically connected to the objective lens 21 and the photodetector 24, respectively. On the other hand, the photodetector 24 is electrically connected to the preamplifier 25. On the other hand, the preamplifier 25 is electrically connected to the RF circuit unit 17. On the other hand, the RF circuit unit 17 is electrically connected to the demodulator 18 and the system controller 19. On the other hand, the demodulator 18 is electrically connected to the system controller 19. In the system controller 19, the recording strategy adjuster 26 is electrically connected to the CPU 27.

An example in the present embodiment will be described. In this embodiment, the LD 23 used in the optical head 13 has a wavelength of 405 nm, an NA (numerical aperture) of 0.65, and a maximum output power of 12 mW. Further, PRML detection is used for reproduction, and a Viterbi decoder for PR (1, 2, 2, 2, 1) is used.

As an optical disc 11, that is, a reproduction information recording medium, an HD DVD-RW capable of overwrite recording is prepared. This time, the recording layer of this HD DVD-RW uses an inorganic material corresponding to a short wavelength. This inorganic material is a type in which the reflectance is lowered when recording is performed, and an optical disk 11 of a kind called high-to-low media is used. As a physical structure of the optical disk, a guide groove called a pregroove is formed on a transparent disk-shaped substrate made of polycarbonate and having a thickness of 0.6 mm and a diameter of 12 cm. During recording and reproduction, a light beam of an information recording / reproducing apparatus, that is, an optical disc drive can be scanned along the guide groove. A recording film is formed on the substrate. As the physical format, an in-groove format having a bit pitch of 0.15 μm and a track pitch of 0.40 μm was used. As the modulation / demodulation code, an ETM (Eight to Twelve Modulation) code based on (1, 7) RLL is used.

The operation of each component of the information recording / reproducing apparatus in this embodiment will be described. The spindle drive system 12 is for driving the optical disc 11. The optical head unit 13 is for irradiating the optical disk 11 with light and detecting the reflected light. The RF circuit unit 17 is for performing processing such as filtering on the input signal. The demodulator 18 is for demodulating the input signal. The system controller 19 is for controlling the entire apparatus. The modulator 16 is for modulating a signal to be recorded. The LD driver 15 is for driving the LD 23. The servo controller 14 is for controlling servo signals. The beam splitter 22 is for reflecting the light from the LD 23 to the objective lens 21 and allowing the reflected light from the optical disk 11 to pass through the photodetector 24.

A recording strategy adjuster 26 is built in the system controller 19. The recording strategy adjuster 26 is for controlling adjustment of the pulse width of each pulse of the recording strategy or power relation such as recording power, erasing power, bias power and the like. Note that a storage unit (not shown) for storing predetermined information in advance may be further incorporated in the system controller 19. The predetermined information stored here will be described later.

A characteristic element of the present invention is the recording strategy adjuster inside the system controller of FIG. In this embodiment, the RF circuit unit 17 measures an amplitude value, a PRSNR value, and an asymmetry β value as signal quality. This measurement result is stored as a correspondence between the amplitude value or asymmetry value and the recording power or erasing power. The measurement result is sent to the CPU 27 in the system controller together with a predetermined determination value used for determining the performance index and its corresponding relationship under various conditions. The CPU 27 performs various determinations and selections using these data.

The signal from the photodetector 24 is input to the RF circuit unit 17 and subjected to processing such as filtering, equalizing, and PLL. When PRML is used, processing such as Viterbi decoding is also performed here.

FIG. 6 is a schematic block diagram of the RF circuit unit 17 used in this embodiment. The RF circuit unit 17 includes a pre-filter 31, an AGC (Auto Gain Controller, auto gain controller) 32, an ADC (Analog / Digital Converter, A / D converter) 33, and a PLL (Phase Locked Loop, Phase Locked Loop) 34. And an adaptive equalizer 35, a discriminator 36, and a signal quality calculator 40. The signal quality calculator 40 includes a PRSNR calculator 37, an asymmetry calculator 38, and an amplitude calculator 39.

The prefilter 31 is connected to the AGC 32. On the other hand, the AGC 32 is connected to the ADC 33, the asymmetry calculator 38, and the amplitude calculator 39. On the other hand, the ADC 33 is connected to the PLL 34. On the other hand, the PLL 34 is connected to the adaptive equalizer 35. On the other hand, the adaptive equalizer 35 is connected to a discriminator 36 and a PRSNR calculator 37. In addition, the discriminator 36 is connected to an adaptive equalizer 35 and a PRSNR calculator 37.

The asymmetry β value and amplitude value of the signal that has passed through the AGC are calculated in an analog manner by a β value calculator or an amplitude calculator. This β value calculator or amplitude calculator includes a peak detector, a bottom detector, and a calculator.

This β value calculator or amplitude calculator can also perform these calculations digitally. In that case, there is a configuration example in which the asymmetry β value and the amplitude value are calculated by a digital processing β value calculator or an amplitude calculator after using a signal digitized by the ADC. At this time, the digital processing type β value calculator or the amplitude calculator includes a peak detector, a bottom detector, an average calculator, and an arithmetic unit.

The signal after adaptive equalization and the data string signal after Viterbi decoding are input to the PRSNR calculator, and the PRSNR value is calculated. Noise at each time required for PRSNR calculation includes the data string signal after Viterbi decoding, the ideal signal waveform obtained by convolution integration of (1, 2, 2, 2, 1) vector, and the signal after adaptive equalization (actual Signal waveform). Also in the PRML detector, the asymmetry value can be calculated using the difference between the ideal signal waveform and the signal after the equalization (actual signal waveform). When a PRML detector is used, a pattern selector is added, and asymmetry can be calculated from the minimum reproduction amplitude by the shortest mark (space) and the long mark (space) indicating the maximum reproduction amplitude. It is also possible to calculate from an amplitude corresponding to a mark (space) that is 1T longer than the shortest mark (space) and a long mark (space) indicating the maximum reproduction amplitude. For example, the minimum mark (space) is 2T, the mark (space) 1T longer than 2T is 3T, and the maximum amplitude is 8T or 13T.

The PRSNR value, asymmetry value, and amplitude value are sent from the RF circuit unit 17 to the recording strategy adjuster 26. The recording strategy adjuster 26 receives the number of PI errors obtained from the demodulated data string from the demodulator 18. The recording strategy adjuster 26 recognizes the correspondence between the recording conditions and the signal quality based on these data, controls a series of adjustment sequences, and adjusts the optimum recording strategy. The PI error (number) means the total number of rows in which an error is detected by the parity on the inner side of ECC (Error Correction Code), and is used in the meaning that is almost qualitatively equal to the error rate. The

At this time, the recording strategy adjuster 26 controls the adjustment method shown in FIG.

FIG. 7 is a flowchart of a recording strategy adjustment method in this embodiment. This flowchart includes a start step, a pulse train waveform parameter setting step S100, a first recording power selection step S200, a reference erase power selection step S300, a reference recording power selection step S400, and a reference cooling pulse width selection step S500. A search setting range end step S600, a pulse train waveform parameter change step S700, a final strategy selection step S800, and an end step.

In this flowchart, steps S100 to S600 are sequentially executed in this order from the start step. In step S600, if the search setting range is complete, the process proceeds to step S800, and if not complete, the process proceeds to step S700. When the pulse train waveform parameter is changed in step S700, the process returns to step S100. When a final strategy is selected in step S800, the process proceeds to an end step.

As a recording strategy, a pulse train type strategy of (k-1) rule consisting of a plurality of pulses is used. For example, when the recording mark length is kT (k is a natural number of 2 or more, T is a channel clock period), for example, recording is performed according to a rule that the recording mark length is formed by k-1 recording (heating) pulse groups. It is a strategy.

8A and 8B are diagrams for explaining a pulse train type recording strategy according to the present invention. FIG. 8A is a waveform diagram for explaining a 5T mark to be recorded in the pulse train type recording strategy according to the present invention. FIG. 8B is a waveform diagram illustrating a pulse train waveform at a 5T mark of the pulse train type recording strategy according to the present invention. Here, the horizontal axis represents the passage of time, and the vertical axis represents the intensity of the pulse signal.

First, as a step not shown in the flowchart of FIG. 7, the information recording / reproducing apparatus reads information held in advance in a specific area of the disc. This information is, for example, Disc Manufacturing information including information on the disc manufacturer name, production location, and disc type. Based on these pieces of information, it is determined that the optical disk is a medium manufactured by the medium manufacturer R and is a High-to-Low type HD DVD-RW that has a low reflectance when recording is performed. Here, some or all of the information may be insufficient. In preparation for such a case, it is desirable that the optical information recording / reproducing apparatus according to the present invention holds predetermined information corresponding to an assumed medium in advance. This predetermined information may be stored in, for example, a storage unit (not shown) included in the system controller 19. If the feature of the medium can be limited, the optical information recording / reproducing apparatus according to the present invention may select and use corresponding information from predetermined information. In addition, if the feature of the medium cannot be limited, an average parameter may be used as an initial value. Further, as parameters relating to recording, parameters relating to recording may be used as long as the pulse width and recording power in the recording strategy are held in the medium. At this time, it is desirable to appropriately determine and operate in advance whether to use medium information, apparatus information, or information as a combination of both. Subsequently, the recording area is searched to determine in which area the mark is recorded. A region where a pattern row is not formed is specified, and the steps shown in the flowchart of FIG. 7 are sequentially performed.

In the pulse train waveform parameter setting step S100, in the pulse train recording strategy, all recording (heating) pulses have the same pulse width, and the cooling pulse following the last pulse is set to a predetermined initial value. In this example, the description will be made assuming that there is no cooling pulse (zero value), but the initial value is not limited to this. For example, it may be set as a minimum value that can be set, and may be a value larger than zero. In order to clarify the adjustment effect by cooling, it is preferable to set the value as small as possible (the cooling width is small). In FIG. 8B, the first pulse, the intermediate pulse, and the last pulse correspond to recording (heating) pulses. Furthermore, the head pulse, the intermediate pulse, and the last pulse all have the same pulse width of 0.40 T (T is the channel clock period). Further, the pulse width search range in the pulse train is set to 0.40T to 0.70T, and the step width to be changed within this range is set to 0.10T.

Since it is known that the influence of the bottom power is almost hidden by the influence of other parameters, this embodiment is fixed at 0.1 mW.

Erase power is fixed at 1.0 mW as power that is not substantially applied. There is no cooling pulse at this point.

In the first recording power selection step S200, the recording power is increased by 1.0 mW from 6.0 mW, which is about half the maximum output power, based on the setting in step S100. Further, recording is performed in units of 1 ECC block, the recorded area is reproduced, and the asymmetry value is measured. At this time, the relationship as shown in FIG. 9 is obtained.

FIG. 9 is a graph showing an example of the relationship between the maximum amplitude value Vpp of the reproduction signal and the asymmetry β value when the recording power Pp is changed under the condition that the erasing power is not substantially applied to the area where the recording mark is not formed. It is. In this graph, the horizontal axis represents the recording power Pp, one of the vertical axes represents the asymmetry β value of the reproduction signal when the recording power is changed, and the other vertical axis represents the amplitude value Vpp corresponding to the same reproduction signal. Show. In this example, the amplitude value is an amplitude in a mark space of 8T or more. Asymmetry is shown up to a power exceeding -30%.

Here, for example, a recording power Pp = 10 mW at which asymmetry is −25% is selected. This is the first recording power selection step S200. Note that the asymmetry changes as the recording power increases, since the mark becomes longer relative to the space. Further, as a predetermined value, if the direction in which the mark is relatively long with respect to the space is a minus direction, the asymmetry value is preferably about −25% or more, but is not limited thereto. Here, 25% indicates that a sufficiently large mark is recorded even at the shortest mark length in the configuration and recording density of the present embodiment.

This step is characterized by finding a recording power that can sufficiently form a mark using the asymmetry β value. In the present invention, the recording power with the absolute value of asymmetry exceeding a predetermined value eliminates the need for extra recording.

For example, as an example, an amplitude saturation detection method that changes the recording power and detects the degree of saturation of the specific mark amplitude is taken as an example. This method is a method in which recording power is changed, recording is performed until the amplitude value becomes substantially constant, and a power capable of sufficiently forming a mark is obtained from the relationship between the amplitude and the recording power. That is, since it is necessary to increase the power until the amplitude becomes substantially constant, it is necessary to perform recording more than necessary. Furthermore, as shown in FIG. 11, even if the recording power is increased, the amplitude may not show a saturation tendency, which is not always a good method.

In the reference erasing power selection step S300, first, the power of 10 mW selected in the first recording power selection step S200 is fixed as the recording power. Next, while increasing the erasing power from 1 mW to 5 mW in increments of 0.5 mW, recording is performed in units of ECC blocks, and the recorded area is reproduced. As shown in FIG. 10, the correspondence between the amplitude value Vpp and the asymmetry β value is obtained with respect to the erasing power Pe.

FIG. 10 is a graph showing an example of the relationship between the maximum amplitude Vpp of the reproduction signal and the asymmetry β value when the erasing power Pe is increased with the recording power as the first recording power. In this graph, the horizontal axis represents the erase power Pe, one of the vertical axes represents the asymmetry β value of the reproduction signal when the erase power is changed, and the other vertical axis represents the amplitude value Vpp corresponding to the same reproduction signal. Show.

Here, the amplitude value is lower than the erasing power in the vicinity where the change decreases significantly, the polarity of the asymmetry is the same as the result of the first recording power selection step (“−: minus” in this example), and its absolute value Is selected as a reference erase power, which is Pe = 4.0 mW.

In the reference recording power selection step S400, first, as determined in the reference erase power selection step S300, the erase power is set to 4.0 mW. Next, the recording power is gradually reduced from 10 mW to 8.0 mW in increments of 0.2 mW, recording is performed in units of ECC blocks, and the recorded area is reproduced. With respect to the decrease in recording power, the polarity of the asymmetry value in the reference erasing power selection step S300 changes in polarity (in this example, changes from-: minus to +: plus), and its absolute value is a second predetermined value. The recording power that is equal to or less than the value of is selected as the reference recording power.

Here, the second predetermined value is (+) 2%. Therefore, as the change step size of the recording power in this example, 9.4 mW is selected as the reference recording power from FIG. This is the second recording power selection step.

FIG. 12 is a graph showing an example of a change in the asymmetry value β when the recording power Pp is lowered with the erasing power as the reference erasing power. In this graph, the horizontal axis represents the recording power Pp, and the vertical axis represents the asymmetry β value of the reproduction signal when the recording power is changed.

A relationship as shown in FIG. 12 is obtained as a change in the asymmetry value β (%) when the recording power Pp is changed from 10 mW to 8.8 mW. When the second predetermined value is set to + 2%, recording, reproducing the recorded portion, obtaining the β value of the reproduction signal, determining whether or not the predetermined value is exceeded, as follows: It is also possible to repeat the procedure of lowering the recording power and continuing the recording, and stop recording at this step when recording is performed at 9 mW.

Subsequently, in the reference cooling pulse width selection step S500, the reference recording power is set to 9.4 mW and the reference erase power is set to 4.0 mW. Then, a cooling pulse is arranged subsequent to the last pulse of the pulse train, and the pattern width is recorded by changing the pulse width of the cooling pulse to a plurality of pulse width conditions increased by approximately 0.03T.

The reproduction signal quality value obtained from the reproduction signal corresponding to each cooling pulse width obtained by reproducing the recorded pattern sequence is measured, and the cooling pulse width when the better reproduction signal quality is obtained is determined as the reference cooling pulse width. Select as

The PRSNR is 23 when the cooling pulse width is 0.09T. This is the cooling pulse width selection step.

In the search setting range end determination step S600, if the search of the search range of the set pulse width has been completed, the process proceeds to the final strategy selection step S800. This time, since the search of the search range of the set pulse width is 0.40T to 0.70T, it is determined that the pulse width is within the range and the search range has not ended. Therefore, in the pulse train waveform parameter changing step S700, the pulse width is set to 0.50T, and the process returns to the pulse train waveform parameter setting step S100.

After each step from step S100 to step S600 is repeated until the corresponding parameter is selected when the pulse width is 0.70T, in this example, the search of the search range ends with a pulse width of 0.70T. The process proceeds to final strategy selection step S800.

At this point, for example, a combination of the reference recording power, the reference erasing power, and the reference cooling pulse width is obtained as shown in FIG.

Fig. 13 shows parameter set No. It is a table | surface which shows 1, 2, 3, 4. For each parameter set, a pulse width, a reference recording power, a reference erase power, and a reference cooling pulse width are set.

In the final strategy selection step S800, the parameter set No. that gives the best PRSNR value or the minimum number of PI errors is selected. 3 is selected.

In the final strategy selection step S800, if there is a parameter set having the same performance, a parameter having a possibility of less performance degradation is selected. For example, in the case shown in FIG. 14, by comparing the difference with the adjacent performance, the difference between the parameter set 3 and the adjacent performance is small. Good. Alternatively, the final parameter may be obtained by calculating an average or median of parameter sets that have a predetermined performance or higher. For example, in FIG. 14, when the average of the parameter groups 2 and 3 having a PRSNR value exceeding 20 is used as a parameter, the pulse width is 0.55 T, the reference recording power is 9.3 mW, and the reference erase power is 4.0 mW. Therefore, the reference cooling pulse width is 0.045T.

FIG. 14 is a graph showing an example of the relationship of the best PRSNR value in each parameter group in a certain parameter group. In this graph, the horizontal axis represents each parameter set, and the vertical axis represents PRSNR corresponding to each parameter set.

In the reference recording power selection step S400, if the predetermined performance is satisfied, the reference cooling pulse width selection step S500 may not necessarily be executed. In this case, assuming that the PRSNR value is about 20 as the predetermined performance, the parameter set No. in FIG. With 1, the PRSNR is 21. Here, although it is inferior to the performance carried out until the final adjustment, depending on the apparatus, there is no problem in operation, it is possible to make the adjustment faster by applying this method.

In addition, after the reference erasing power is selected in step S300, the selection of the reference recording power may be performed by overwrite recording in step S400.

Further, on the basis of the parameters obtained above, the power adjustment step size for searching for the recording power and the erasing power may be further reduced to perform detailed power adjustment. In this case, it is preferable to perform detailed adjustment by over-write recording.

Further, as detailed adjustments other than the power, the adjustment of the first pulse width and the adjustment of the final pulse width of the pulse train strategy may be divided into 2T, 3T, 4T or more, and further detailed adjustment may be performed.

Also, a pattern corresponding adjustment for adjusting the leading or final pulse width may be performed according to the space length immediately before or after the recording mark. In this case, the adjustment time becomes long, but there is a possibility that a parameter that draws higher performance can be found.

Since which adjustment is performed and how much is related to adjustment accuracy and adjustment time, it is preferable to determine in advance at the device design stage in consideration of various constraints.

As described above, using a pulse train having regularity with the same pulse width, first, a power for sufficiently forming a recording mark is found (first recording power selection step S200). Next, a reference erase power is selected below (reference erase power selection step S300). Next, a reference recording power is selected under the reference erasing power (reference recording power selection step S400). Furthermore, by adjusting the cooling pulse lastly (reference cooling pulse width selection step S500), it becomes possible to correct the distortion of the recording mark, thereby improving the linearity. The asymmetry value is mainly used for selection, and the asymmetry change direction is determined by the recording power, erasing power, or the width of the cooling pulse following the last pulse in the pulse train, with the asymmetry value being zero. Adjustments are made using the knowledge that changes.

FIG. 15 is a block diagram for explaining the configuration of the recording strategy adjuster 26 when it is implemented as a computer or a part of a computer. In this case, the recording strategy adjuster 26 can be understood as comprising a memory 52, an input device 53, an output device 54, and a bus 51 connecting them. As a CPU necessary for the recording strategy adjuster 26 to operate as a computer, a CPU 27 connected to the recording strategy adjuster 26 is used as shown in FIG.

In the recording strategy adjusting method according to the present invention described above, each step shown in FIG. 7 is preferably implemented in a computer as a program.

FIG. 16 is a block diagram for explaining each function when the system controller 19 is implemented as a computer or a part of a computer. In this case, the recording strategy adjuster 26 includes a pulse train waveform parameter designing unit 61, a first recording power selecting unit 62, a reference erasing power selecting unit 63, a reference recording power selecting unit 64, and a reference cooling pulse width selecting unit. 65, a search setting range determination unit 66, a pulse train waveform parameter change unit 67, and a final strategy selection unit 68.

Here, the pulse train waveform parameter design unit 61 performs an operation corresponding to step S100. The first recording power selection unit 62 performs an operation corresponding to step S200. The reference erasing power selection unit 63 performs an operation corresponding to step S300. The reference recording power selection unit 64 performs an operation corresponding to step S400. The reference cooling pulse width selection unit 65 performs an operation corresponding to step S500. Search setting range determination unit 66 performs an operation corresponding to step S600. The pulse train waveform parameter changing unit 67 performs an operation corresponding to step S700. The final strategy selection unit 68 performs an operation corresponding to step S800.

Steps S200 to S500 are respectively a parameter setting within a predetermined range, a recording on the optical disc with the set parameter, a reproduction of the recorded signal, a measurement based on the reproduced signal, and a parameter based on the measurement result. Is selected. Therefore, the first recording power selection unit 62, the reference erasing power selection unit 63, the reference recording power selection unit 64, and the reference cooling pulse width selection unit 65 are respectively a setting unit, a recording unit, and a reproduction unit. It can be understood that the measurement unit and the selection unit are provided.

(Second Embodiment)
The configuration of the information recording / reproducing apparatus in the second embodiment of the present invention is substantially the same as that of the first embodiment. However, another operation is added in the reference recording power selection step S400 in the operation of the recording strategy adjuster 26. As a result, restrictions on the parameter setting accuracy can be relaxed, so that more versatile adjustment is possible.

The reference recording power selection step S400 and subsequent steps that are characteristic of this embodiment will be described below. A detailed description of the configuration of the information recording / reproducing apparatus and an operation description from step S100 to step S300, which are the same processes as those in the first embodiment, are omitted.

In the reference recording power selection step S400, the erasing power is fixed to 4.0 mW as determined in the reference erasing power selection step S300. Next, the recording power is gradually reduced from 10 mW to 8.0 mW in increments of 0.2 mW, recording is performed in units of ECC blocks, and the recorded area is reproduced. With respect to the decrease in recording power, the polarity of the asymmetry value in the reference erasing power selection step S300 changes in polarity (in this example, changes from-: minus to +: plus), and its absolute value is a second predetermined value. The recording power that is equal to or less than the value of is selected as the reference recording power.

Here, unlike the first embodiment, the second predetermined value is (+) 5%. For example, when the recording power Pp is changed from 10 mW to 8.8 mW, the case where the relationship shown in FIG. 12 is obtained as the change of the asymmetry value β (%) is used. In this case, two reference recording powers, 9.2 mW and 9.4 mW, are selected. This is the second recording power selection step S400 in the second embodiment.

Subsequently, in the reference cooling pulse width selection step S500, two cases are selected as the reference cooling pulse width. That is, when the reference recording power is 9.2 mW and the reference erasing power is 4.0 mW (set A), and when the reference recording power is 9.4 mW and the reference erasing power is 4.0 mW (set B). There are two ways.

For each of the two cases, a cooling pulse is first placed following the last pulse in the pulse train. Next, the pattern row is recorded by changing the pulse width of the cooling pulse to a plurality of pulse widths increased by approximately 0.03T. Next, the reproduction signal quality value obtained from the reproduction signal corresponding to each cooling pulse width obtained by reproducing the recorded pattern sequence is measured. In this way, the cooling pulse width when better reproduction signal quality is obtained is selected as the reference cooling pulse width.

The PRSNR is 22 when the cooling pulse width that provides the best performance in Set A is 0.09T. In the set B, the PRSNR is 23 when the cooling pulse width is 0.06T. Therefore, in this case, the set B having the better PRSNR is selected. The recording power and erasing power selected in this adjustment are the powers in Set B, and the cooling pulse width is 0.06T. This is the cooling pulse width selection step in the second embodiment.

Since the search setting range end determination step S600 and subsequent steps are the same as those in the first embodiment, description thereof is omitted.

Also in the second embodiment, as in the first embodiment, the reference cooling pulse width selection step S500 is not necessarily executed if the predetermined performance is satisfied in the reference recording power selection step S400. Also good. If the PRSNR is about 20 as the predetermined performance, it is preferable that the reference recording power is selected with an index indicating the absolute value of the performance in the reference recording power selection step S400. That is, in the present embodiment, when the reference recording power selection step S400 is completed, the PRSNR is 20 for the set A and the PRSNR is 22 for the set B, and the parameters of the set B remain. In this case, the adjustment can be performed at a higher speed.

The reason why such a method is effective is that the setting accuracy of the cooling pulse width and the degree of influence thereof may be different. Consider a case where the asymmetry value is 0% or more and the second predetermined value is within a range of about + 5% to + 10%, for example, + 10%. At this time, the recording power corresponding to the range of the asymmetry value from 0% to 10% is obtained. However, depending on the step size of the search power, a plurality of cases where the asymmetry is + 10% or less may be obtained. Therefore, by adjusting the cooling pulse width for each combination and determining the final parameter combination with an index indicating the absolute performance, a more versatile method is obtained.

(Other embodiments)
The setting range of the pulse width or recording and erasing power, and the change step width in the present invention are not limited to the above-described embodiment, but are preferably changed as appropriate according to the head and circuit configuration to be used.

Further, in the above embodiment, the area unit used for the test recording is 1 ECC unit, but the present invention is not limited to this. In that case, there may be a case where each of a plurality of sector units, a plurality of frame units, or a combination thereof is used.

In the recording pulse adjustment (pulse width adjustment) in the present invention, the pulse change position is preferably the same front end or rear end.

Further, the present invention is not limited to a wavelength of 405 nm and NA of 0.65, and can be applied to any wavelength and numerical aperture NA.

In the above embodiment, the class PR (12221) is used, but other classes such as PR (1221) and PR (3443) can be used in the same manner.

In addition, the ETM used in the HD DVD as a modulation code has been described so far, but other modulation codes can be used similarly. In that case, for example, the shortest data length may be kT (k is a natural number of 3 or more).

In the above embodiment, the HD DVD is used as the optical disc, but a Blu-ray disc (BD disc) may be used.

Also, in the case of a medium having a signal polarity in the direction in which the recorded mark becomes brighter, so-called Low-to-High polarity, the polarity of the β value may be reversed.

In addition, although the PRSNR value is used as the performance index, other performance index may be used. For example, the number of error bytes or an error rate (PRSNR can be converted into an error rate) may be used. Alternatively, SAM (Sequence Amplitude Margin) may be used. Further, even an index based on SAM, an index that can be basically replaced with an error rate index may be used. In addition, the total number of rows in which an error is detected by the number of error bytes generated in a predetermined number of ECC blocks or the parity on the inner side of the ECC, which is an index used in a qualitatively equivalent sense to the error rate. A PI error that is a number may be used. Jitter may be used in a system that does not use PRML detection.

It should be noted that the present invention is not limited to the above-described embodiments, and it is obvious that each embodiment can be appropriately changed within the scope of the technical idea of the present invention.

The present invention can be widely applied as a recording / reproducing apparatus and a recording strategy adjusting method for a high-density optical disc, and can obtain an effect of remarkably increasing the reliability of the recording / reproducing apparatus.

According to the present invention, the adjustment of the recording strategy can be performed quickly and reliably. The reason is that it is possible to find the first recording power at which the mark can be sufficiently formed at a high speed, and to find the reference erasing power below it. Further, this is because the next parameter search range can be narrowed down by selecting the reference erasing power. Moreover, it is because the reference recording power can be obtained at high speed by having a necessary guideline that the power should be reduced from the first recording power.

Also, by paying attention to the change direction of the asymmetry value due to the change of the parameter and its absolute value, it is possible to prevent the adjustment from being locally optimized, so that a reliable adjustment is possible.

Also, the area of the medium used for recording adjustment can be reduced. The reason is that, as compared with the case where all parameter combinations are used, since a procedure with a line of sight is used, waste can be eliminated. Furthermore, having a prospect as a procedure makes it possible to make a wide and versatile adjustment without requiring much experience and skill in adjusting the recording strategy.

The optical information recording / reproducing program according to the present invention is readable by a computer for causing the computer to execute each of the steps in the optical information recording method according to the present invention.
The recording strategy adjustment program according to the present invention is readable by a computer for causing the computer to execute each step in the recording strategy adjustment method according to the present invention.

The recording medium according to the present invention records a computer-readable optical information recording / reproducing program for causing the computer to execute each step in the optical information recording method according to the present invention.
The recording medium according to the present invention records a recording strategy adjustment program readable by a computer for causing the computer to execute each of the steps in the recording strategy adjustment method according to the present invention.

As mentioned above, although this invention was invented with reference to embodiment, this invention is not limited to the said embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

The content of Japanese Patent Application No. 2008-78922, which is the basic application of the present application, is incorporated into the present application by the disclosure of this application number.

Claims (12)

1. Reading predetermined information stored in advance on an optical information recording medium capable of overwriting;
   Either one of the predetermined information, another predetermined information held in advance in an apparatus for recording / reproducing information on the medium, and information obtained by mixing the predetermined information and the other predetermined information. Selecting and adjusting a recording strategy for recording on the optical information recording medium based on the selected information;
   Generating a recording signal based on the adjusted recording strategy,
   The step of adjusting the strategy includes:
   Setting an initial value for each of a plurality of parameters in the waveform of the pulse train strategy;
   Selecting a first recording power based on an initial value set for each of the plurality of parameters;
   Selecting a reference erase power based on the selected first recording power;
   Selecting a reference recording power based on an initial value set for each of the plurality of parameters, the selected first recording power, and the selected reference erasing power;
   The length of the reference cooling pulse is selected based on the initial value set for each of the plurality of parameters, the selected first recording power, the selected reference erasing power, and the reference recording power. Comprising the steps of:
   The step of setting an initial value for each of the plurality of parameters includes:
   Setting a predetermined recording pulse width initial value as a width common to a plurality of recording pulses of the waveform;
   Setting a predetermined initial value of the cooling pulse width as the width of the cooling pulse of the waveform;
   Setting a predetermined bottom power initial value as the value of the bottom power of the waveform;
   A step of setting a predetermined initial value of erasing power as a value of erasing power that the waveform has,
   The step of selecting the first recording power includes:
   Sequentially setting a plurality of values included in a predetermined range as the value of the first recording power;
   For each of the plurality of values, recording a signal on the optical information recording medium based on the selected first recording power;
   Replaying the recorded signal from the optical information recording medium for each of the plurality of values;
   Measuring an asymmetry value for each of the plurality of values based on the reproduced signal;
   Selecting the most preferred first recording power value based on the measured asymmetry value,
   The criterion for selecting the most preferable first recording power value is that the absolute value of the asymmetry value corresponding to the first recording power value exceeds a predetermined value,
   The step of selecting the reference erasing power includes:
   Sequentially setting a plurality of values included in a predetermined range as the value of the reference erasing power;
   For each of the plurality of values, recording a signal on the optical information recording medium with the set reference erasing power;
   Replaying the recorded signal from the optical information recording medium for each of the plurality of values;
   Measuring an amplitude value and an asymmetry value based on the reproduced signal for each of the plurality of values;
   Selecting the most preferred reference erasure power value based on the measured amplitude value and the asymmetry value;
   The criterion for selecting the most preferable reference erasing power value is a value lower than the erasing power in the vicinity where the decrease rate of the amplitude value reaches the maximum value, and the polarity of the asymmetry value is the first recording power selection step. An optical information recording / reproducing method, wherein the absolute value of the asymmetry value is minimized.
2. In the optical information recording / reproducing method according to claim 1,
   Of the plurality of parameters in the waveform of the pulse train type strategy, after changing a width common to the plurality of recording pulses within a predetermined search range, setting an initial value for each of the plurality of parameters, Repeating the steps of selecting the first recording power, selecting the reference erasing power, selecting the reference recording power, and selecting a length of the reference cooling pulse;
   Selecting the most preferred recording strategy in each of the widths common to the plurality of recording pulses,
   The step of repeating the five steps is:
   An optical information recording / reproducing method comprising: a step of selecting the most preferable recording strategy when it is determined that an end of a search range having a width common to the plurality of recording pulses is determined.
3. In the optical information recording and reproducing method according to claim 2,
   The step of selecting the reference recording power includes
   Sequentially setting a plurality of values included in a predetermined range as the reference recording power value;
   For each of the plurality of values, recording a signal on the optical information recording medium with the set reference recording power;
   Replaying the recorded signal from the optical information recording medium for each of the plurality of values;
   Measuring an asymmetry value for each of the plurality of values based on the reproduced signal;
   Selecting the most preferred reference recording power value based on the measured asymmetry value,
   The criterion for selecting the most preferable reference recording power value is that the polarity of the asymmetry value in the step of selecting the reference erasing power changes with respect to the decrease in the reference recording power, and its absolute value is The optical information recording / reproducing method is to be equal to or less than a second predetermined value.
4. In the optical information recording / reproducing method according to claim 2 or 3,
   The step of selecting the length of the reference cooling pulse includes:
   Sequentially setting a plurality of values included in a predetermined range as the length of the reference cooling pulse;
   For each of the plurality of values, recording a signal on the optical information recording medium with the set reference cooling pulse length;
   Replaying the recorded signal from the optical information recording medium for each of the plurality of values;
   Measuring a reproduced signal quality value for each of the plurality of values based on the reproduced signal;
   Selecting a length of a reference cooling pulse having the best measured reproduction signal quality value. An optical information recording / reproducing method.
5. In the optical information recording / reproducing method according to any one of claims 2 to 4,
   Selecting the most preferred recording strategy comprises:
   An optical information recording / reproducing method comprising a step of selecting a recording strategy with less performance deterioration when a plurality of the preferred recording strategies are found.
6. In the optical information recording / reproducing method according to any one of claims 1 to 5,
   A recording strategy adjustment method comprising the step of adjusting the recording strategy.
7. A reproduction signal readout circuit unit for reading out predetermined information stored in advance on an optical information recording medium capable of overwriting;
   Based on the selected information by selecting any one of the predetermined information, another predetermined information held in advance by itself, and information obtained by mixing the predetermined information and the other predetermined information. A recording strategy adjusting unit for adjusting a recording strategy for recording on the optical information recording medium,
   A recording signal generation circuit unit that generates a recording signal based on the recording strategy adjusted by the recording strategy adjustment unit;
   The recording strategy adjustment unit
   A pulse train waveform parameter setting unit for setting an initial value for each of a plurality of parameters in the waveform of the pulse train type strategy;
   A first recording power selection unit for selecting a first recording power based on an initial value set for each of the plurality of parameters;
   A reference erasing power selection unit for selecting a reference erasing power based on the selected first recording power;
   A reference recording power selection unit for selecting a reference recording power based on an initial value set for each of the plurality of parameters, the selected first recording power, and the selected reference erasing power;
   The length of the reference cooling pulse is selected based on the initial value set for each of the plurality of parameters, the selected first recording power, the selected reference erasing power, and the reference recording power. And a reference cooling pulse selection unit
   Initial values set for each of the plurality of parameters in the waveform of the pulse train strategy are as follows:
   A predetermined recording pulse width initial value set as a width common to a plurality of recording pulses of the waveform;
   A predetermined cooling pulse width initial value set as the width of the cooling pulse of the waveform;
   A predetermined bottom power initial value set as a value of the bottom power of the waveform;
   A predetermined erase power initial value set as a value of the erase power that the waveform has,
   The first recording power selection unit includes:
   A first setting unit that sequentially sets a plurality of values included in a predetermined range as the value of the first recording power;
   For each of the plurality of values, a first recording unit that records a signal on the optical information recording medium with a first recording power set by the first setting unit;
   For each of the plurality of values, a first reproducing unit that reproduces a signal recorded by the first recording unit from the optical information recording medium;
   For each of the plurality of values, a first measurement unit that measures an asymmetry value based on a signal reproduced by the first reproduction unit;
   A first selection unit that selects a most preferable first recording power value based on the asymmetry value measured by the first measurement unit;
   The criterion for selecting the most preferable first recording power value is that the absolute value of the asymmetry value corresponding to the first recording power value exceeds a predetermined value,
   The reference erasure power selection unit is
   A second setting unit that sequentially sets a plurality of values included in a predetermined range as the value of the reference erasing power;
   For each of the plurality of values, a second recording unit that records a signal on the optical information recording medium with a reference erasing power set by the second setting unit;
   For each of the plurality of values, a second reproduction unit that reproduces a signal recorded by the second recording unit from the optical information recording medium;
   For each of the plurality of values, a second measurement unit that measures an amplitude value and an asymmetry value based on a signal reproduced by the second reproduction unit;
   A second selection unit that selects a most preferable reference erasing power value based on the amplitude value measured by the second measurement unit and the asymmetry value;
   The criterion for selecting the most preferable reference erasing power value is a value lower than the erasing power in the vicinity where the decrease rate of the amplitude value reaches the maximum value, and the polarity of the asymmetry value is the first recording power selection step. An optical information recording / reproducing apparatus having the same absolute value as the asymmetry value, which is the same as the above result.
8. The optical information recording / reproducing apparatus according to claim 7,
   The recording strategy adjustment unit
   Of the plurality of parameters in the waveform of the pulse train type strategy, after changing a width common to the plurality of recording pulses within a predetermined search range, the pulse train waveform parameter setting unit and the first recording power selection A pulse strain waveform parameter changing unit for operating the reference erasing power selecting unit, the reference recording power selecting unit, and the reference cooling pulse selecting unit,
   A final strategy selecting unit for selecting a most preferable recording strategy in each of the widths common to the plurality of recording pulses;
   An optical information recording / reproducing apparatus, further comprising: a search setting range determination unit that operates the final strategy selection unit when it is determined that a search range having a width common to the plurality of recording pulses is ended.
9. In the optical information recording / reproducing apparatus according to claim 8,
   The reference recording power selection unit is
   A third setting unit that sequentially sets a plurality of values included in a predetermined range as the value of the reference recording power;
   For each of the plurality of values, a third recording unit that records signals on the optical information recording medium at a reference recording power set by the third setting unit;
   For each of the plurality of values, a third reproducing unit that reproduces the signal recorded by the third recording unit from the optical information recording medium;
   For each of the plurality of values, a third measurement unit that measures an asymmetry value based on the signal reproduced by the third reproduction unit;
   A third selection unit that selects a most preferable reference recording power value based on the asymmetry value measured by the third measurement unit;
   The criterion for selecting the most preferable reference recording power value is that the polarity of the asymmetry value measured by the first measurement unit changes with respect to the decrease in the reference recording power, and the absolute value is the first value. 2. An optical information recording / reproducing apparatus that is less than or equal to a predetermined value of 2.
10. In the optical information recording / reproducing apparatus according to claim 8 or 9,
    The reference cooling power selection unit is
    A fourth setting unit that sequentially sets a plurality of values included in a predetermined range as the length of the reference cooling pulse;
    For each of the plurality of values, a fourth recording unit that records a signal on the optical information recording medium at the length of the reference cooling pulse set by the fourth setting unit;
    A fourth reproduction unit for reproducing the signal recorded by the fourth recording unit from the optical information recording medium for each of the plurality of values;
    For each of the plurality of values, a fourth measurement unit that measures a reproduction signal quality value based on the signal reproduced by the fourth reproduction unit;
    An optical information recording / reproducing apparatus comprising: a fourth selection unit that selects a length of a reference cooling pulse having the best reproduction signal quality value measured by the fourth measurement unit.
11. In the optical information recording / reproducing apparatus according to any one of claims 8 to 10,
    An optical information recording medium control unit for recording the signal generated by the recording signal generation circuit unit on the optical information recording medium, and reproducing an arbitrary signal recorded on the optical information recording medium;
    A system controller for controlling the recording signal generation circuit unit, the optical information recording medium control unit, and the reproduction signal readout circuit unit;
    The system controller is
    Comprising the recording strategy adjustment unit;
    The recording signal generation circuit unit is connected to the first recording unit, the second recording unit, the third recording unit, and the fourth recording unit,
    The reproduction signal readout circuit unit is connected to the first reproduction unit, the second reproduction unit, the third reproduction unit, and the fourth reproduction unit. Optical information recording / reproduction device.
12. 12. A recording strategy adjusting unit in the optical information recording / reproducing apparatus according to claim 7.

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