WO2011052029A1

WO2011052029A1 - Information recording device and method, and computer program

Info

Publication number: WO2011052029A1
Application number: PCT/JP2009/068350
Authority: WO
Inventors: 正次布施; 淳一古川
Original assignee: パイオニア株式会社
Priority date: 2009-10-26
Filing date: 2009-10-26
Publication date: 2011-05-05
Also published as: JPWO2011052029A1

Abstract

An information recording device (1) particularly comprises a first calculating means for calculating the asymmetry value and the degree of modulation when recording information using the target laser power of laser light and the target laser power using a recording strategy for recording the information at a first recording speed at the first recording speed, an acquisition means for acquiring a special OPC strategy which specifies the waveform of the laser light used to calculate the optimum laser power of the laser light when recording the information at the first recording speed at a second recording speed different from the first recording speed on the basis of the recording strategy, an adjustment means for performing (i) the adjustment of laser power specified by the special OPC strategy based on at least either the asymmetry value or the degree of modulation, and (ii) the adjustment of the recorded waveform specified by the special OPC strategy, and a second calculating means for calculating the optimum laser power using the adjusted special OPC strategy at the second recording speed, and records the information at the first recording speed using the calculated optimum laser power and the recording strategy.

Description

Information recording apparatus and method, and computer program

The present invention is provided in an information recording apparatus that records information by irradiating an information recording medium such as an optical disk with laser light, and controls a laser driving apparatus that controls irradiation while changing the output of the laser light, The present invention relates to a technical field of an information recording apparatus including a laser driving device.

In general, in an information recording apparatus that records data by irradiating a laser beam to an information recording medium such as an optical disk, the type of the optical disk, the type of the information recording apparatus, and the like are obtained by OPC (Optimum Power Calibration) processing. Depending on the recording speed or the like, for example, the optimum laser power of the laser beam used for the recording operation or the like is set. In other words, laser power calibration is performed. For this reason, it becomes possible to irradiate laser light with an appropriate laser power, and a suitable recording operation can be realized. Typically, when an optical disc is loaded and a command for data recording is input, the light intensity of the test writing data is switched sequentially and gradually with respect to the PCA (Power Calibration Area) provided on the optical disc. Thus, the so-called trial writing process is executed. Thereafter, the test writing data recorded in this manner is reproduced, and the reproduction result is determined based on a predetermined evaluation standard, and the optimum laser power is set.

Also, in the technical field of information recording devices, a technology for increasing the information recording speed by increasing the rotational speed of the optical disc has been developed. For example, in a CD-ROM which is an example of an optical disk, the recording speed of data is increased to 24 times or 48 times as the rotation speed of the optical disk increases.

When the rotational speed of the optical disk is increased in this way, generally, it is preferable that the OPC process is performed at the same linear speed (that is, actual double speed) as when data is actually recorded. However, since the OPC process is generally performed on the innermost circumference side of the optical disk, the linear velocity is hardly generated at the same rotation speed, and the rotation is controlled in the OPC process when executing recording at a relatively high speed. There is a technical problem that the actual linear velocity cannot be realized on the innermost circumference side due to restrictions such as the motor standard. In particular, in CLV (Constant-Liner-Velocity) in which the linear velocity is constant in any recording area of the optical disc, the innermost circumferential rotation speed is larger than the outermost circumferential rotation speed. For this reason, for example, in order to realize a recording speed or linear velocity of 8 × speed in a DVD as a specific example of an optical disk, high-speed rotation of 12000 rpm is required on the innermost circumference side. Such high-speed rotation is difficult to realize due to the motor standard, and has a technical problem that the optical disk rotating at the rotation speed is also damaged. In addition, even if such high-speed rotation is realized, the servo that controls the motor becomes unstable, and further, there is a technical problem that the detection accuracy of recording quality such as asymmetry and β decreases. ing.

In response to such a background, a technique for performing the OPC process on the outermost peripheral side of the optical disc has been studied. Generally, the outermost peripheral side is compared with the region from the inner peripheral portion to the middle peripheral portion of the disc. Thus, it is difficult to make the quality of the recording layer uniform in the substrate molding stage, and there is a technical problem that non-uniformity in recording sensitivity occurs to some extent in the manufacturing stage. Further, at the outermost periphery of the optical disc, when a user handles the optical disc, contamination such as scratches and fingerprints is likely to occur, and the uniformity of recording sensitivity may be further impaired. For this reason, even if the OPC process is performed on the outermost peripheral side of the optical disk, there may be a problem in the accuracy of the calculated optimum laser power.

In view of such a technical problem, for example, in Patent Document 1, a plurality of OPC processes are performed on the outer peripheral PCA, and an abnormal value caused by an effect of a scratch, a fingerprint, or the like is excluded, thereby suitable recording. A technique for setting power is disclosed. Further, in Patent Document 2, an OPC process using a special OPC strategy is executed at a recording speed that is different from the actual recording speed and at which the OPC process can be executed in the innermost PCA. Thus, a technique for obtaining an optimum recording power at an actual recording speed is disclosed. Patent Document 3 discloses a so-called recording compensation technique that adjusts the position (in other words, pulse width) of a recording pulse defined in the recording strategy in accordance with the recording speed.

JP 2001-331940 A International Publication No. 05/043515 Pamphlet International Publication No. 09/016753 Pamphlet

As described above, in the OPC process using the outer peripheral portion of the optical disc, when determining the recording laser power without considering the nonuniformity of the recording sensitivity, the recording laser power different from the original optimum power is set as the optimum recording power. There is a risk of being set. For example, the configuration disclosed in Patent Document 1 is a configuration in which a suitable recording laser power is obtained by excluding abnormal values from results obtained by a plurality of times of OPC processing. However, a reduction in the accuracy of the recording laser power due to the nonuniformity of the recording sensitivity is not completely avoided.

Further, in the configuration described in Patent Document 2, as the ratio of the actual double speed linear velocity of the optical disk during recording and the linear velocity at the time of performing OPC processing increases, the recording laser power acquisition system by OPC decreases. There is a technical problem. In addition, this method requires that a dedicated OPC strategy for performing OPC is set in advance, and for such an unknown optical disk in which such a dedicated OPC strategy is not set, in other words, There is also a technical problem that OPC processing cannot be performed at different recording speeds.

Due to the above-described decrease in the accuracy of the OPC process, the recording quality of the data is deteriorated, and reading of the recorded data becomes unstable during reproduction, so that the accuracy of the OPC can be improved as much as possible. preferable.

The present invention has been made in view of the above-described conventional problems, for example, and an information recording apparatus and method capable of executing, for example, laser beam calibration processing in consideration of the recording sensitivity of an optical disc during high-speed rotation, It is another object of the present invention to provide a computer program for realizing such an information recording apparatus.

In order to solve the above-described problems, an information recording apparatus of the present invention includes a recording unit that irradiates an information recording medium with laser light and records information on the information recording medium, and the first recording at a first recording speed. First calculation means for calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power, using a recording strategy for recording the information at a speed And calculating an optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed based on the recording strategy. Acquisition means for acquiring a special OPC strategy that defines a waveform of the laser beam to be used; and (i) the special OPC strategy based on at least one of the asymmetry value and the modulation degree And (ii) adjusting means for adjusting a recording waveform specified in the special OPC strategy based on the recording speed, and the adjustment adjusted at the second recording speed. The information is recorded at the first recording speed by using a second calculation means for calculating the optimum laser power using a special OPC strategy, and the calculated optimum laser power and the recording strategy. Control means for controlling the recording means.

In order to solve the above problems, an information recording method of the present invention includes a recording step of irradiating an information recording medium with laser light to record information on the information recording medium, and the first recording at a first recording speed. A first calculation step of calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power, using a recording strategy for recording the information at a speed And calculating an optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed based on the recording strategy. An acquisition step of acquiring a special OPC strategy that defines a waveform of the laser light to be used; and (i) the special OPC strategy based on at least one of the asymmetry value and the modulation degree And (ii) an adjustment step for adjusting a recording waveform specified in the special OPC strategy based on the recording speed, and the adjustment performed at the second recording speed. A second calculation step of calculating the optimum laser power using a special OPC strategy, and the information is recorded at the first recording speed using the calculated optimum laser power and the recording strategy. A control step of controlling the laser power of the laser beam in the recording step.

In order to solve the above problems, a computer program according to the present invention includes a recording means for irradiating an information recording medium with laser light to record information on the information recording medium, and the first recording speed at the first recording speed. And a first calculation means for calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power, using a recording strategy for recording the information in , Based on the recording strategy, used to calculate an optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed. Acquisition means for acquiring a special OPC strategy that defines a waveform of the laser light to be generated; and (i) the special OPC based on at least one of the asymmetry value and the modulation degree Adjustment of the laser power specified in the C strategy, and (ii) adjusting means for adjusting the recording waveform specified in the special OPC strategy based on the recording speed, and adjusted at the second recording speed The information is recorded at the first recording speed using a second calculation means for calculating the optimum laser power using the special OPC strategy and the calculated optimum laser power and the recording strategy. A computer program for recording control for controlling a computer provided in an information recording apparatus comprising: control means for controlling the recording means; wherein the computer comprises the recording means, the first calculating means, and the second calculating means. It functions as at least a part of the calculation means, the acquisition means, the adjustment means, and the control means.

In order to solve the above problems, an information recording medium of the present invention defines an information recording area for recording information and a waveform of the laser beam used for recording the information at a first recording speed. A control area for recording a recording strategy to be recorded, wherein the information recording area has a portion where the information can be recorded at the first recording speed and a second recording speed different from the first recording speed. And a portion where the information can be recorded.

The operation and other advantages of the present invention will be clarified from the embodiments described below.

It is the schematic which shows roughly the structure of the information recording medium of a present Example. It is a block diagram which shows roughly the structure of the information recording device of a present Example. It is a flowchart which shows an example of the OPC processing operation by the information recording device of a present Example. It is a flowchart which shows an example of adjustment operation of the OPC strategy by the information recording device of a present Example. It is the typical timing chart which showed OPC processing of 16 power steps. FIG. 5 is a schematic diagram showing waveforms of a normal OPC strategy and a special OPC strategy in a recording pulse for each recording speed. It is a graph which shows the relationship between the recording power in an information recording device, (beta), and a modulation degree.

<1>
An embodiment according to the information recording apparatus of the present invention comprises a recording means for irradiating an information recording medium with laser light to record information on the information recording medium, and the information at the first recording speed at the first recording speed. First calculation means for calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power, using a recording strategy for recording The laser used for calculating the optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed based on a strategy. An acquisition means for acquiring a special OPC strategy that defines a light waveform; and (i) specified in the special OPC strategy based on at least one of the asymmetry value and the modulation factor. Adjustment of laser power, and (ii) adjustment means for adjusting a recording waveform defined in the special OPC strategy based on the recording speed, and the special OPC strategy adjusted at the second recording speed. And controlling the recording means to record the information at the first recording speed using the second calculating means for calculating the optimum laser power and the calculated optimum laser power and the recording strategy. Control means.

According to the embodiment of the information recording apparatus of the present invention, information including various data such as video information, music information, computer data, etc., for example, spiral or concentric circles is obtained by the operation of the recording means. It can be recorded on an information recording medium such as an optical disk having a track. At this time, the information recording medium mounted on the information recording apparatus is rotated by an operation of a spindle motor or the like included in the information recording apparatus, and a recording speed (for example, linear speed) corresponding to the rotation speed (typically linear speed) (for example, The information is recorded at a first recording speed and a second recording speed described later in detail.

In the present embodiment, in particular, information is recorded at the first recording speed using a second recording speed different from the first recording speed according to the rotational speed of the information recording medium when actually recording information. It is possible to calculate the optimum laser power for this purpose. Specifically, the optimum laser power is calculated by OPC processing in which laser power adjustment is performed by performing trial writing on the information recording medium at the second recording speed. In the OPC process at this time, a special OPC strategy different from the recording strategy used for recording actual information is used.

Here, the recording strategy is control information that defines the waveform of a laser beam (for example, pulse width and amplitude described later) used when information is recorded at the first recording speed, for example, for 8x described later. For example, a recording strategy. Such a recording strategy is generally recorded in advance in an area where management information of an information recording medium is recorded, or can be generated relatively easily from some information recorded in advance. . For example, in an information recording medium that is a BD (Blu Ray Disc), a recording strategy can be created relatively easily based on strategy data stored in a disc information file (Disc Information File).

The special OPC strategy is control information that defines the waveform of the laser beam used when obtaining the optimum laser power of the laser beam at the first recording speed. For example, a special OPC strategy described later or 6x Special OPC strategy. That is, the special OPC strategy defines the waveform of the laser beam that can calculate the optimum laser power at the first recording speed by recording information such as an OPC pattern at the second recording speed (in other words, trial writing). ing. Here, the “optimum laser power” in the present invention is not limited to literally the most suitable laser power for information recording, but also a laser power that can record information more appropriately during recording. It is a broad intent. More specifically, the optimum laser power is such that, for example, the influence of asymmetry does not affect the recording operation, or the error rate is zero or can be realized in such a low state that the recording operation is not substantially affected. It is preferable that the laser power be

In the present embodiment, the OPC process using the recording strategy is executed at the first recording speed by the operation of the first calculating means, and the optimum laser power for recording information at the first recording speed (that is, the present embodiment) Target laser power in the form) is calculated. The recording strategy is obtained by reading what is previously recorded on the information recording medium as described above. Note that before calculating the target laser power using the recording strategy, the recording strategy may be optimized by performing a so-called recording compensation operation with an OPC process interposed therebetween. By performing such a recording compensation operation, it is possible to enjoy the advantage that the recording strategy can be adjusted so that information can be recorded with higher accuracy.

By the way, the calculated target laser power may not necessarily enable appropriate information recording depending on the rotational speed for realizing the first recording speed or the standard limitation of the spindle motor. For example, when the first recording speed is relatively high and the OPC process cannot be performed by the PCA provided on the innermost circumference side of the information recording medium, the OPC process is performed on the outermost PCA instead. However, the laser power calculated by the OPC process in the outermost peripheral PCA is likely to cause a problem in accuracy due to the above-described problems. Accordingly, in such a case, when information is recorded using the target laser power calculated by performing the OPC process at the first recording speed (typically, at the outer peripheral side PCA), the recording quality is There is a technical problem that can cause degradation.

On the other hand, in order to calculate the optimum laser power at the first recording speed, it is not necessary to actually perform the OPC process at the first recording speed, and information such as an OPC pattern is obtained at a second recording speed different from the first recording speed. It can also be realized by recording.

In order to realize the OPC processing at such different recording speeds (that is, the second recording speed), the embodiment of the information recording apparatus of the present invention specifically calculates the optimum laser power at the first recording speed. A special OPC strategy that defines the waveform of the laser beam to be used is used. That is, the OPC process at the second recording speed is performed using a strategy different from the normal recording strategy used when recording information such as content at the first recording speed.

A plurality of such special OPC strategies are stored in advance in correspondence with the medium information of the information recording medium in storage means such as a memory provided in the information recording apparatus as will be described later, and are used for recording information. A special OPC strategy that matches the recording characteristics of the information recording medium to be recorded is acquired by the acquisition means. According to such a configuration, a special OPC strategy can be acquired relatively easily.

On the other hand, when the special OPC strategy is not stored in advance, in other words, for an information recording medium unknown to the information recording apparatus, the acquisition unit records information on the information recording medium at the second recording speed, for example. A special OPC strategy may be created based on the recording strategy.

However, when the optimum laser power is calculated using such a special OPC strategy as it is, the accuracy is not always suitable for information recording. For this reason, according to the embodiment of the information recording apparatus of the present invention, it is calculated by OPC processing using the special OPC strategy by adjusting at least one of the laser power and the pulse width defined in the special OPC strategy. The accuracy of the optimum laser power can be further improved.

Specifically, the adjusting means of the present embodiment adjusts at least one of a laser power and a recording waveform for recording information defined in the special OPC. At this time, the adjusting means uses at least one of a modulation factor and an asymmetry value as parameters indicating a recording condition in the OPC process for calculating the target laser power performed using the recording strategy by the operation of the first calculating means. Based on the above, the laser power adjustment specified in the special OPC strategy is performed. The asymmetry value is a meaning indicating a calculated value of asymmetry.

At this time, the adjusting means, specifically, the parameters such as the modulation degree and the asymmetry value are within a predetermined range based on the value in the recording condition when the target laser power is calculated by the OPC process at the first recording speed (for example, Then, the laser power is regulated as specified in the special OPC strategy so as to be about ± 5%. For example, when considering the case where the information recording medium is a BD, the adjusting means uses the laser mark corresponding to the peak of the recording mark among the plurality of types of laser power defined in the special OPC strategy as a reference. The so-called space power output that regulates the normal power and the space portion is adjusted.

According to such special OPC strategy adjustment, the output of the laser power specified in the special OPC strategy is adjusted as described above. For this reason, β such as the modulation degree and the asymmetry value is adjusted to be substantially equal to that at the time of recording at the first recording speed. This reduces the average recording laser power in the recording means, can suppress changes in characteristics and damage of the recording film of the information recording medium due to excessive heat irradiation, and is suitable for loss of linearity of the β curve due to modulation degree saturation. It becomes possible to prevent. For this reason, it is possible to use a recording sensitivity range substantially equivalent to that at the time of recording at the first recording speed, and it is possible to calculate the optimum laser power with higher accuracy.

Further, the adjusting means may adjust the recording waveform defined in the special OPC strategy. At this time, the adjusting means typically adjusts the pulse width in the recording waveform defined in the special OPC strategy by recording compensation based on the difference in recording speed. At this time, as will be described later, for short marks (specifically, 2T marks and 3T marks in the case of BD, etc.), for example, the pulse width is adjusted in accordance with the ratio between the first recording speed and the second recording speed. Is done. On the other hand, for other recording waveforms excluding such short marks, the pulse width is adjusted according to the recording speed ratio for the highest power portion, and the overall pulse length is adjusted for the other portions. Therefore, the pulse width is adjusted as appropriate.

Then, the second calculation means calculates the optimum laser power at the first recording speed by, for example, recording an OPC pattern or the like at the second recording speed using the laser light defined by the special OPC strategy. The recording of the OPC pattern or the like is preferably performed by the recording unit under the control of the second calculation unit. Then, by the operation of the control means, the recording means (particularly, the laser beam) is controlled so as to record information with the calculated optimum laser power.

As described above, in the present embodiment, the target laser power obtained by the OPC process performed at the first recording speed used for information recording is not adopted as it is. With reference to the recording conditions in the OPC process for calculating the target laser power, a target value of an OPC process using a special OPC strategy (hereinafter referred to as a special OPC process as appropriate) is determined, and the first recording speed is The laser power calculated as a result of the special OPC process at a different second recording speed is adopted as the optimum laser power. For this reason, it is possible to calculate the optimum laser power with high accuracy even under the condition where the optimum laser power with high accuracy cannot be calculated by the OPC processing at the first recording speed. For example, ZCLV (Zone Constant Linear) (Velocity) It is possible to enjoy advantages such as maintaining stable recording quality at the rotation speed switching point.

Such a special OPC strategy is preferably stored in advance in storage means such as a memory provided in the information recording apparatus as described in Patent Document 2 described above. However, since the laser power and recording waveform defined in the special OPC strategy change according to the information recording medium on which information is recorded and the recording speed, all of the special OPC strategies corresponding to each of these various conditions are used. It is difficult to register in advance. Further, there is a possibility that a special OPC strategy cannot be set for an unknown information recording medium. However, according to the information recording apparatus of the present embodiment, the special OPC strategy is acquired from the recording strategy used for recording information, and the special OPC strategy is adjusted. Therefore, the special OPC strategy is not registered in advance. Even the information recording medium can enjoy the effects described above.

As described above, by adjusting the special OPC strategy based on the recording condition in the OPC processing using the recording strategy, it is possible to calculate a suitable optimum laser power suitable for information recording. For example, by adjusting the laser power specified in the special OPC strategy so that parameters such as the degree of modulation and asymmetry become appropriate values, information recording caused by excessive heat irradiation as the average recording power decreases. It becomes possible to suppress the characteristic change and breakage of the recording film of the medium. Further, there is an advantage that it is possible to prevent the loss of linearity of the β curve due to saturation of the modulation degree. By such an adjustment, as a result, it is possible to use a recording sensitivity range that is almost the same as when the OPC process is performed at the first recording speed.

As a result, according to the first embodiment of the information recording apparatus of the present invention, the optimum laser power at the first recording speed is appropriately and accurately calculated without actually recording information at the first recording speed. It becomes possible to do. Therefore, for example, even when the first recording speed is relatively high or relatively low compared with the second recording speed, the optimum laser power can be appropriately calculated.

Note that the information recording apparatus according to the present embodiment can calculate the optimum laser power with higher accuracy when the first recording speed is higher than the second recording speed as described later. On the other hand, it is naturally possible to enjoy the same benefits even when the first recording speed is lower than the first recording speed. That is, the optimum laser power at the first recording speed can be obtained by performing, for example, the OPC process at a second recording speed higher than the first recording speed at which information is actually recorded. In addition, in this case, since an OPC pattern, for example, can be recorded at a relatively high second recording speed, there is also an advantage that the time required for calculating the optimum laser power can be reduced.

<2>
In one aspect of the information recording apparatus of the present invention, the adjusting means adjusts a pulse width corresponding to a code other than a short mark in a recording waveform defined in the special OPC strategy.

According to this aspect, the pulse width of the recording waveform defined in the special OPC strategy typically includes the second recording speed when performing the OPC process using the special OPC strategy, and the special OPC strategy. Adjustment is made based on the first recording speed at the time of recording of information using the basic recording strategy.

In other words, the adjustment means adjusts the recording waveform defined in the special OPC strategy by performing a so-called recording compensation operation that optimizes the special OPC strategy (in other words, the shape or waveform of the recording pulse) according to the recording speed. To do.

Specifically, by optimizing the pulse width of the special OPC strategy according to the clock difference between the first recording speed and the second recording speed (for example, the rate of change in the pulse width of the clock), It becomes possible to adjust to a more suitable special OPC strategy.

Note that the adjusting means basically does not adjust the pulse width of a pulse corresponding to a so-called short mark in the recording waveform defined in the special OPC strategy. Here, the short mark basically indicates a shortest mark or a mark having a length in the vicinity of the shortest mark among a plurality of pulses having a pulse width that is an integral multiple of the clock frequency of the recording signal. It is the purpose. For example, when recording information on a BD is considered, there are marks having a length of 2T to 9T. At this time, the short marks generally indicate 2T and 3T marks.

Since a pulse corresponding to such a short mark generally does not change the pulse width when converted to a clock according to the recording speed, it is not necessary to adjust the pulse width.

With this configuration, the special OPC strategy can be adjusted more suitably, and the optimum laser power can be calculated with high accuracy. In addition, there is an advantage that the load applied to the adjustment operation can be reduced by not adjusting the portion of the recorded waveform that does not require adjustment.

<3>
In another aspect of the embodiment of the information recording apparatus of the present invention, the adjusting means includes: (i) adjusting the ratio of the space power to the peak power defined in the special OPC strategy based on the asymmetry value; and (ii ) At least one of adjustment of the ratio of the middle power to the peak power defined in the special OPC strategy based on the modulation degree is performed.

According to this aspect, the adjusting means adjusts the laser power defined in the special OPC strategy based on at least one of the modulation degree and the asymmetry value detected by the OPC process using the special OPC strategy. Specifically, at least one of the modulation degree and the asymmetry value is within a predetermined range based on the value in the recording condition when the target laser power is calculated by the OPC process at the first recording speed using the recording strategy (for example, Then, the laser power is regulated as specified in the special OPC strategy so as to be about ± 5%. For example, when considering the case where the information recording medium is a BD, the adjusting means uses the laser mark corresponding to the peak of the recording mark among the plurality of types of laser power defined in the special OPC strategy as a reference. The so-called space power output that regulates the normal power and the space portion is adjusted. At this time, the modulation degree can be adjusted by adjusting the power output of the mark portion, and the asymmetry can be adjusted by adjusting the space power output. In this way, the laser power is adjusted by the adjusting means.

<4>
In another aspect of the embodiment of the information recording apparatus of the present invention, the first recording speed is higher than the second recording speed.

According to this aspect, it is possible to appropriately calculate the optimum laser power for recording information at a recording speed that cannot be obtained by actually operating the information recording medium. In particular, in an information recording medium that records information by rotating an optical disc such as a DVD or a BD, for example, in the rotation for a recording operation in CLV, the rotation on the innermost circumference side compared to the outermost circumference side of the disc Tends to increase the linear velocity. For this reason, in performing the OPC process for calculating the optimum laser power when recording information at a relatively high rotational speed (for example, the rotational speed for realizing the first recording speed), typically, the innermost circumference of the disk is used. In some cases, it is not possible to realize proper information recording by the PCA provided on the side. However, in the OPC process using the PCA on the outermost peripheral side of the disk, the calculation accuracy of the optimum laser power is low for the reasons described above, and there is a technical request to perform the OPC process on the PCA on the innermost peripheral side if possible.

However, according to the present embodiment, the OPC process is performed at the second recording speed by rotating the information recording medium at the rotational speed that realizes the second recording speed that is relatively lower than the first recording speed. Thus, there is a great advantage that the optimum laser power for recording information at the first recording speed can be appropriately calculated.

<5>
Another aspect of the embodiment of the information recording apparatus of the present invention is to obtain medium information for specifying the information recording medium, and (i) store the medium information and the special OPC strategy related to the information recording medium. And (ii) storage means for performing at least one of recording on the information recording medium, wherein the acquisition means is medium information in which medium information acquired from the information recording medium is stored in the storage means If it matches, the special OPC strategy stored corresponding to the medium information is acquired.

According to this aspect, the acquisition unit can acquire the special OPC strategy stored in the storage unit relatively easily. Specifically, the acquisition means is information currently used from a combination of a plurality of types of medium information and special OPC strategies registered in firmware stored in advance for operating the information recording apparatus. The medium information of the recording medium is searched, and the corresponding special OPC strategy is acquired. For this reason, the acquisition unit can acquire the special OPC strategy relatively easily by reading the data related to the special OPC strategy.

Further, by adjusting the acquired special OPC strategy by the adjusting means, it becomes possible to acquire a more accurate OPC strategy based on the recording quality on the information recording medium.

Further, the special OPC strategy generated or adjusted as described above is stored in the information recording apparatus or recorded on the information recording medium by the operation of the storage means. For this reason, the above-mentioned effect can be enjoyed by referring to the stored or recorded special OPC strategy at the next recording / reproducing operation. For this reason, it is possible to perform recording of information with a more accurate optimum laser power.

<6>
An embodiment of the information recording method of the present invention includes a recording step of irradiating an information recording medium with laser light to record information on the information recording medium, and the information at the first recording speed at the first recording speed. A first calculation step of calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power using a recording strategy for recording The laser used for calculating the optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed based on a strategy. An acquisition step of acquiring a special OPC strategy that defines a light waveform; and (i) a special OPC strategy based on at least one of the asymmetry value and the modulation degree. Adjustment of laser power, and (ii) an adjustment step of adjusting a recording waveform defined in the special OPC strategy based on the recording speed, and the special OPC strategy adjusted at the second recording speed. A second calculating step for calculating the optimum laser power, and the information in the recording step so as to record the information at the first recording speed using the calculated optimum laser power and the recording strategy. A control step of controlling the laser power of the laser light.

According to the embodiment of the information recording method of the present invention, similarly to the above-described embodiment of the information recording apparatus of the present invention, using the special OPC strategy acquired in the acquisition step and adjusted in the adjustment step, The optimum laser power can be calculated in the second calculation step. Then, the power of the laser beam can be controlled in the control process, and information can be recorded with the optimum laser power in the recording process. In particular, as described above, the optimum laser power at the first recording speed can be obtained by recording an OPC pattern or the like at the second recording speed, for example. For this reason, it is possible to appropriately perform laser beam calibration processing even during high-speed recording operation (that is, during high-speed rotation).

Incidentally, in response to the various aspects of the embodiments of the information recording apparatus of the present invention described above, the embodiments of the information recording method of the present invention can also adopt various aspects.

<7>
According to an embodiment of the computer program of the present invention, there is provided recording means for irradiating an information recording medium with laser light to record information on the information recording medium, and at a first recording speed, the information is recorded at the first recording speed. First recording means for calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when recording the information using the target laser power using a recording strategy for recording, and the recording strategy The laser beam used for calculating the optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed. Acquisition means for acquiring a special OPC strategy that defines the waveform of (i), and (i) the special OPC strategy based on at least one of the asymmetry value and the modulation factor (Ii) adjusting means for adjusting a recording waveform specified in the special OPC strategy based on the recording speed; and the special OPC adjusted at the second recording speed. Second recording means for calculating the optimum laser power using a strategy; and the recording so as to record the information at the first recording speed using the calculated optimum laser power and the recording strategy. A computer provided in an information recording apparatus (that is, an embodiment according to the above-described information recording apparatus of the present invention, and preferably including various aspects thereof) including control means for controlling the means A computer program for recording control, the computer comprising the recording means, the first calculation means, the second calculation means, the acquisition means, and the adjustment means Function as at least one portion of the fine said control means.

According to the embodiment of the computer program of the present invention, the computer program is read from a recording medium such as a ROM, a CD-ROM, a DVD-ROM, and a hard disk that stores the computer program, and executed. If the computer program is downloaded to a computer via communication means and then executed, the above-described embodiment of the information recording apparatus of the present invention can be realized relatively easily.

Incidentally, in response to the various aspects of the embodiment of the information recording apparatus of the present invention described above, the embodiment of the computer program of the present invention can also adopt various aspects.

According to an embodiment of the computer program product of the present invention, an information recording medium is irradiated with laser light to record information on the information recording medium, and the information is recorded at the first recording speed at the first recording speed. First calculation means for calculating a target laser power of the laser beam and an asymmetry value and a modulation degree when the information is recorded using the target laser power, using a recording strategy for recording The laser used for calculating the optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed based on a strategy. Acquisition means for acquiring a special OPC strategy that defines a light waveform; and (i) the special OPC strike based on at least one of the asymmetry value and the modulation degree Adjustment of the laser power specified in the stage, and (ii) adjustment means for adjusting the recording waveform specified in the special OPC strategy based on the recording speed, and the adjustment adjusted at the second recording speed The information is recorded at the first recording speed by using a second calculation means for calculating the optimum laser power using a special OPC strategy, and the calculated optimum laser power and the recording strategy. A computer provided in an information recording apparatus (that is, an embodiment according to the above-described information recording apparatus of the present invention, and preferably including various aspects thereof) including a control means for controlling the recording means. Executable program instructions are clearly embodied, and the computer includes the recording means, the first calculation means, the second calculation means, and the acquisition means. Function as at least one portion of said adjusting means and said control means.

According to the embodiment of the computer program product of the present invention, if the computer program product is read into a computer from a recording medium such as a ROM, a CD-ROM, a DVD-ROM, and a hard disk storing the computer program product, or For example, if the computer program product, which is a transmission wave, is downloaded to a computer via communication means, the above-described embodiment of the information recording apparatus of the present invention can be implemented relatively easily. More specifically, the computer program product may be configured by computer-readable code (or computer-readable instruction) that functions as an embodiment of the information recording apparatus of the present invention described above.

Incidentally, in response to the various aspects of the embodiment of the information recording apparatus of the present invention described above, the embodiment of the computer program product of the present invention can also adopt various aspects.

<8>
An embodiment according to the information recording medium of the present invention includes an information recording area for recording information, and a recording strategy for defining a waveform of the laser beam used for recording the information at a first recording speed. A control area for recording, wherein the information recording area includes a portion where the information can be recorded at the first recording speed and a second recording speed different from the first recording speed. And a site where recording is possible.

According to the embodiment of the information recording medium of the present invention, information including various contents such as video information and music information or data information for a computer is recorded in the information recording area. In the control area, the above recording strategy is recorded. Therefore, an information recording apparatus such as a DVD recorder can enjoy various benefits of various aspects of the above-described information recording apparatus according to the above-described information recording apparatus relatively easily by reading the recording strategy recorded in the control area. I can do it.

As described above, according to the embodiment of the information recording apparatus of the present invention, the recording apparatus, the first calculation means, the acquisition means, the second calculation means, the adjustment means, and the control means are provided. According to the embodiment of the information recording method of the present invention, the information recording method includes a recording step, a first calculation step, an acquisition step, a second calculation step, an adjustment step, and a control step. According to the embodiment of the computer program of the present invention, the computer is caused to function as at least a part of the recording unit, the first calculation unit, the acquisition unit, the second calculation unit, the adjustment unit, and the control unit. According to the embodiment of the information recording medium of the present invention, the information recording area and the control area are provided. Accordingly, it is possible to calculate the optimum laser power at the recording speed used for recording actual information, preferably at an arbitrary recording speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1) Introduction In the following description, the constant x is a predetermined reference value, and the recording speed of data on the optical disk is indicated by 4x, 6x and 8x. That is, the recording speed represented by 8x is approximately twice the recording speed represented by 4x. This reference value x may be determined according to the standard of the drive or optical disc, or may be arbitrarily determined by the manufacturer of the information recording / reproducing apparatus. In the following description, the description will proceed assuming that there are three types of recording speeds of the optical disc 100: 4x, 6x, and 8x. It goes without saying that the configuration described in the present embodiment can be realized even when recording speeds other than those exemplified above are used. A specific example of “first recording speed” in the present invention corresponds to “8x recording speed” in the present embodiment, and “second recording speed” in the present invention corresponds to “4x recording speed” in the present embodiment. This corresponds to “speed” or “6 × recording speed”.

Also, here is a brief explanation of the various strategies that appear frequently in the following explanation. “Lx recording strategy (l = 4, 6, 8)” is strategy information used to control the waveform of a laser beam for recording various data including normal contents at a recording speed of lx. It is. That is, it corresponds to a specific example of “recording strategy” in the present invention.

“Special OPC strategy for mx (m = 4, 6)” is a waveform of a laser beam when an OPC pattern described later is recorded at a recording speed of mx in order to calculate an optimum laser power at a recording speed of 8x. Strategy information used for control. That is, it corresponds to a specific example of “special OPC strategy” in the present invention.

(2) Basic Configuration of Optical Disc Next, with reference to FIG. 1, the basic configuration of the optical disc 100 that is the target of the recording operation of the information recording apparatus 1 according to the present embodiment will be described. FIG. 1 is a schematic plan view showing the basic structure of the optical disc 100, and is a schematic conceptual diagram of the recording area structure in the radial direction of the optical disc 100. As shown in FIG.

As shown in FIG. 1, an optical disc 100 is a specific example of an “information recording medium” in the present invention, and has a recording surface on a disc main body having a diameter of about 12 cm on the inner peripheral side with a center hole 101 as a center. A PCA (Power Calibration Area) 111, an RMA (Recording Management Area) 112, a lead-in area 113, a data recording area 114, a lead-out area 115, and an outer PCA 116 that constitute one specific example of the “information recording area” in the present invention. For example, BD (Blu-dayluDisc) is provided. For example, a groove track and a land track are alternately provided in a spiral shape or a concentric shape around the center hole 101. On this track, the data pattern is divided and recorded in units of ECC blocks. The ECC block is a data management unit capable of error correction. In this embodiment, the optical disc 100 may be a write-once recording medium that can record a data pattern only once, or a rewritable recording medium that can record a data pattern multiple times. There may be.

Particularly in this embodiment, as shown in the lower part of FIG. 1, a control area 113 a which is a specific example of the “control area” in the present invention is provided in the lead-in area 113. In the control area 113a, an 8x recording strategy to be described later is recorded. Here, the 8x recording strategy is control information for controlling the waveform of a laser beam for recording data at a recording speed of 8x.

In general, in data recording by an information recording apparatus that records data by rotating the optical disc 100, particularly CLV recording, the rotational speed of the optical disc 100 for realizing one recording speed is from the outer circumference side to the inner circumference. Increasing toward the side. For this reason, there are cases where the recording speed that can be realized on the outer peripheral side cannot be realized on the inner peripheral side due to the limitation of the spindle motor standard for rotating the optical disc 100 or the like. In the present embodiment, in particular, the inner circumference side PCA 111 can record data at a recording speed of 4x, and cannot record data at a recording speed of 8x. , It is assumed that data can be recorded at recording speeds of 4x and 8x.

(3) Basic Configuration Example of Information Recording Device Next, the basic configuration of the information recording device according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram schematically showing the basic configuration of the information recording apparatus 1 according to this embodiment.

As shown in FIG. 2, the information recording apparatus 1 according to the present embodiment includes a spindle motor 310, an optical pickup (PU) 320, a CPU 330, an AFE (Analog Front End) 340, and a signal re-recording / reproducing. Part 350.

The spindle motor 310 rotates and stops the optical disc 100 and operates when accessing the optical disc. More specifically, the spindle motor 310 is configured to rotate and stop the optical disc 100 at a predetermined speed while receiving spindle servo from a servo unit (not shown) or the like.

The spindle motor 310 typically operates to rotate the optical disc 100 at a rotation speed capable of realizing a designated recording speed under the control of the CPU 330. For example, when recording data at a recording speed of 8x, the spindle motor 310 operates so that the optical disc 100 rotates faster than when recording data at a recording speed of 4x or 6x. When data is recorded at a recording speed of 6x, the spindle motor 310 operates so that the optical disc 100 rotates at a higher speed than when data is recorded at a recording speed of 4x. In this embodiment, a description will be given of a configuration that uses a recording speed of 8x when recording data, and a recording speed of 4x when recording an OPC pattern for OPC processing.

The optical pickup 320 is a laser device that writes data by irradiating the optical disc 100 with the laser beam LB, and receives an electric current to irradiate the laser beam (not shown). A laser diode driver (LDD: Laser Diode Driver) 321 that controls the supply of current to the LD and the OEIC (Opto-) that receives reflected light from the optical disc 100 and converts it into an electrical signal (for example, a reproduction signal). Electronic (Integrated (Circuit) Circuit) 322 and the like. More specifically, the optical pickup 320 realizes data writing by irradiating the optical disk 100 while modulating the laser light LB with the writing laser power under the control of the LDD 321. Alternatively, the laser beam LB may be irradiated with a power different from the one power, and the reading light may be converted into a reproduction signal by the OEIC 322, thereby reproducing the data recorded on the optical disc 100.

The CPU 330 is connected to each part of the spindle motor 310, the optical pickup 320, the AFE 340, and the signal recording / reproducing unit 350, and controls the entire information recording apparatus 1 by giving instructions to the respective control means. The CPU 330 is connected to the memory 331.

The memory 331 is used in general data processing in the disk drive 300, such as a buffer area for recording / reproducing data and an area used as an intermediate buffer when converted into data usable by the signal recording / reproducing means 350. The memory 331 includes a ROM area in which a program for performing operations as these recorder devices is stored, a buffer used for compression / decompression of video data, and a RAM area in which variables necessary for program operation are stored. .

In the present embodiment, in particular, the memory 331 records an 8x recording strategy and a 4x recording strategy. The memory 331 may store a 4x special OPC strategy or other various strategies. Normally, software for operating the CPU 330 is stored in the memory 331.

The AFE 340 indicates various peripheral circuits connected to the optical pickup 320, the CPU 330, and the information recording / reproducing unit 350, respectively. The AFE 340 includes, for example, a conversion circuit that converts an analog signal such as a reproduction signal photoelectrically converted by the OEIC 322 into digital data, and preferably a clock signal generation circuit that is used when data is recorded.

The signal recording / reproducing unit 350 is a DSP (Digital Signal Processor) that performs generation of a clock signal used at the time of data recording and data recording / reproducing processing, and includes a strategy generating unit 351, a strategy evaluating unit 352, and a special OPC strategy generating. 353, special OPC strategy evaluation unit 354, AD conversion circuit 355, γ detection unit 356, β detection unit 357, jitter detection unit 358, and optimum power estimation unit 359. The signal recording / reproducing unit 350 transmits a recording signal to the optical pickup 320 by the operation of each of these units, and performs recording / reproducing on the optical disc 100 by controlling the spindle motor 310 and the optical pickup 320.

Specifically, the operation of the optical pickup 320 is controlled based on the recording strategy for each data pattern generated by the strategy generating unit 351 (that is, 8x recording strategy), and data recording is performed. At this time, the strategy evaluation unit 352 performs a recording compensation operation for adjusting the 8 × recording strategy based on the jitter measured by the jitter detection unit 358 and the like. Further, under the control of the CPU 330, the OPC process for calculating the optimum laser power at the recording speed of 8x (that is, a specific example of the target laser power in the present invention) is performed using the 8x recording strategy.

In this embodiment, in particular, a special OPC process for calculating the optimum laser power at the recording speed of 8x using the 4x special OPC strategy generated in the special OPC strategy generation unit 353 under the control of the CPU 330. Is implemented. In the OPC processing, an OPC pattern defined by a 4x special OPC strategy is recorded after rotating the optical disc 100 so as to realize a recording speed of 4x.

The γ detection unit 356 is configured to receive an input of the reproduction signal of the optical disc 100 from the optical pickup 320 and measure the modulation degree in the data. Similarly, the β detector 357 is configured to detect an asymmetry value or β value, and the jitter detector 358 is configured to detect a jitter value.

The optimum power estimation unit 359 is configured to receive an input of a modulation degree, a β value, and a jitter value measured from a reproduction signal obtained by reproducing an OPC pattern, and to estimate an optimum laser power.

(4) Basic Operation Example Next, with reference to FIGS. 3 to 7, the basic operation of the information recording apparatus according to the present embodiment will be described. 3 and 4 are flowcharts showing the flow of the basic operation of the information recording apparatus according to the present embodiment. In particular, FIG. 3 shows the flow of the optimum laser power determination operation by the OPC process, and FIG. 4 shows a flow of a special OPC strategy adjustment operation in the operation of FIG. FIG. 5 is a schematic timing chart showing the OPC process of 16 power steps. FIG. 6 is a schematic diagram showing waveforms of a recording strategy and a special OPC strategy in a recording pulse for each recording speed. FIG. 7 is a graph showing the relationship between β and recording power in the special OPC strategy adjustment operation.

As shown in FIG. 3, under the control of the CPU 330, it is determined whether or not the OPC process at the recording speed of 8x can be executed in the inner peripheral side PCA 111 of the optical disc 100 (step S101). Typically, since the OPC process is performed by recording an OPC pattern on the optical disc 100, in other words, in step S101, is it possible to realize a recording speed of 8x in the inner peripheral side PCA? This is an operation for determining whether or not.

As a result of this determination, for example, when it is determined that the OPC process at the recording speed of 8x cannot be realized in the inner peripheral PCA 111 of the optical disc 100 as in the optical disc 100 in the above-described embodiment (step S101: No). ), OPC processing at other recording speeds is performed in order to realize the OPC processing in the inner peripheral side PCA 111. The purpose of this OPC processing is to calculate an optimum laser power at a recording speed of 8 × that cannot be realized by the inner peripheral side PCA 111 by performing OPC pattern recording at a recording speed that can be realized by the inner peripheral side PCA 111. And In order to perform such OPC processing, a special OPC strategy different from the normal recording strategy is required.

In order to acquire such a special OPC strategy, a special OPC strategy for executing a special OPC process in the lead-in area 112 of the optical disc 100 or other parts, or in a memory provided in the information recording apparatus 1 or the like. Is stored (step S102). In other words, it is determined whether or not the recording characteristics of the optical disc 100 at this time are known to the information recording apparatus 1. Here, the special OPC strategy is a 4x special OPC strategy as described above, for example.

When the special OPC strategy is not stored in advance in the optical disc 100 or the memory in the information recording apparatus 1 (step S102: No), the information recording apparatus 1 of the present embodiment performs a series of steps S103 to S107 shown below. Generate and adjust special OPC strategies by action. By performing the special OPC process using such a special OPC strategy, it is possible to calculate the optimum laser power at different recording speeds. In order to perform such special OPC processing, a target value corresponding to the recording strategy that is the basis for generating the special OPC strategy and the optimum recording speed of the optimum laser power is required.

First, the OPC process using the 8x recording strategy is executed in the outer peripheral PCA 116 of the optical disc 100 (step S103). At this time, the 8x recording strategy is generated based on, for example, disk information information recorded on the optical disc 100 in advance. The optimum laser power calculated by the OPC process at this time is temporarily stored in the memory as the provisional optimum laser power.

Here, a detailed description of the OPC process is added. First, under the control of the CPU 330, the optical pickup 320 is moved to the outer peripheral PCA 116, and the recording power is sequentially switched (for example, 16 stages different from each other) by the operations of the strategy generation unit 351 and the LDD 321. An OPC pattern as shown in FIG. 5 is recorded on the outer peripheral side PCA 116. In such an OPC pattern, for example, a recording pattern in which short pits (marks) corresponding to 2T pulses and long pits (spaces) corresponding to 8T pulses are alternately formed with spaces of the same length as one example. For example, the pattern may be a combination of marks and spaces having other lengths, or may be a random pattern. In this embodiment, a waveform defined by the 8 × recording strategy is used as the waveform of the laser beam at this time, and a predetermined OPC pattern is recorded. In a special OPC process to be described later, a waveform defined by a 4x special OPC strategy is used, and a predetermined OPC pattern is recorded.

The LDD 321 drives the semiconductor laser in the optical pickup 320 so that the recording power is sequentially switched in accordance with the OPC pattern output from the strategy generation unit 351.

Furthermore, after completion of such trial writing to the OPC area, the OPC pattern that has been trial-written in the OPC area is reproduced under the control of the CPU 330. Specifically, a peak value and a bottom value of envelope detection of the RF signal are sampled from an RF signal input to an envelope detector (not shown). Then, after such OPC pattern reproduction is performed in one OPC process, for example, according to the number of recorded OPC patterns, the optimum power estimation unit 359 determines the optimum laser power. That is, the peak value and bottom value (in other words, the signal level for generating marks and spaces) of the shortest code length (for example, 2T) and the longest code length (for example, 8T) in these OPC patterns, for example, From the asymmetry calculated based on each of I2H, I2L, I8H, and I8L), for example, the optimum laser power is calculated such that the jitter value indicating the quality of the recording characteristics is near the minimum.

Subsequently, the strategy evaluation unit 352 performs recording compensation of the 8x recording strategy, and the corrected 8x recording strategy is temporarily stored in the memory (step S104). Specifically, referring to the jitter value detected by the jitter detector 358 when data is recorded using the 8x recording strategy, the edge adjustment of the recording waveform defined in the 8x recording strategy is performed.

The outer PCA 116 executes the OPC process using the corrected 8x recording strategy, and the optimum laser power in the 8x recording strategy estimated by the optimum power estimation unit 359 in the γ detection unit 356 and the β calculation unit 357. Each of the degree of modulation and the β value at the time of output is measured (step S105).

Next, the operation of the special OPC strategy generation unit 353 generates a 4x special OPC strategy for performing the special OPC process at a recording speed of 4x (step S106). At this time, the 4x special OPC strategy is generated based on the 8x recording strategy stored in advance in the optical disc 100 or the information recording apparatus 1.

Here, with reference to FIG. 6, an aspect of generating a special OPC strategy based on the recording strategy will be described. FIG. 6 is a schematic diagram showing respective waveforms of NRZI, recording strategy (recording waveform), and special OPC strategy (special OPC recording waveform) in a recording pulse at a recording speed. In the present embodiment, in particular, the maximum amplitude of the L-type strategy waveform shown in FIG. 6 is the peak power (Pw), the minimum amplitude is the cooling power (Pc) for cooling, and one step lower than the peak power. The power is called middle power (Pm), and the power between middle power and cooling power is called space power (Ps).

As shown in the graph on the left side of FIG. 6A, when recording “2T pattern” data on the optical disc 100 at a recording speed of 8 ×, a laser beam corresponding to a pulse of 2 ns is irradiated. When recording “4T pattern” data, a laser beam corresponding to an L-shaped pulse as shown in the graph on the right side of FIG. The shape of these pulses is defined based on an 8 × recording strategy, for example, under the control of the CPU 330.

6B, when recording “2T pattern” data on the optical disc 100 at a recording speed of 6 ×, a laser beam corresponding to a pulse of 3 ns is irradiated. When recording “4T pattern” data, a laser beam corresponding to an L-shaped pulse as shown in the graph on the right side of the middle stage of FIG. 6B is irradiated. The shape of these pulses is defined based on a 6 × recording strategy under the control of the CPU 330, for example.

On the other hand, when the “2T pattern” OPC pattern is recorded at the recording speed of 6 × in order to calculate the optimum laser power at the recording speed of 8 ×, as shown in the lower left side of FIG. Based on the OPC strategy, a laser beam corresponding to a pulse of 2 ns is irradiated. That is, a pulse having the same shape as that for recording a “2T pattern” at a recording speed of 8 × is irradiated. On the other hand, when the “4T pattern” OPC pattern is recorded at a recording speed of 6 ×, a laser beam corresponding to an L-type pulse as shown in the lower right part of FIG. 6B is irradiated. The pulse width at this time is adjusted so that the highest power portion is the same or substantially the same as when recording the data of “4T pattern” at the recording speed of 8 ×, and the recording speed is set for the other portions. Shortly adjusted according to the ratio.

As shown in the graph on the left side of the middle stage of FIG. 6C, when recording “2T pattern” data on the optical disc 100 at a recording speed of 4 ×, a laser beam corresponding to a pulse of 4 ns is irradiated. Further, when the data of “4T pattern” is recorded, a laser beam corresponding to an L-type pulse as shown in the graph on the right side of the middle stage of FIG. 6C is irradiated. The shape of these pulses is defined based on a 4 × recording strategy, for example, under the control of the CPU 330.

On the other hand, when the “2T pattern” OPC pattern is recorded at the recording speed of 4 × in order to calculate the optimum laser power at the recording speed of 8 ×, as shown in the lower left of FIG. Based on the OPC strategy, a laser beam corresponding to a pulse of 2 ns is irradiated. That is, a pulse having the same shape as that for recording the “2T pattern” at the recording speed of 8 × is irradiated. On the other hand, when an “4T pattern” OPC pattern is recorded at a recording speed of 4 ×, a laser beam corresponding to an L-shaped pulse as shown on the lower right side of FIG. The pulse width at this time is adjusted so that the highest power portion is the same or substantially the same as when recording the data of “4T pattern” at the recording speed of 8 ×, and the recording speed of the other portions is the same. Shortly adjusted according to the ratio.

As described above, the 4x special OPC strategy and the 6x special OPC strategy for calculating the optimum laser power at the recording speed of 8x are the lasers defined by the 4x recording strategy or the 6x recording strategy originally used when recording data. It is adjusted to record an OPC pattern by irradiating a laser beam having a shorter pulse compared to the pulse of the beam. More specifically, according to the 6x special OPC strategy, a pulse for recording short mark data such as “2T pattern” is shortened from 3 ns to 2 ns (ie, about 67%). The The pulse for recording the data of “4T pattern” is adjusted so that the pulse width of the highest power portion is the same as or substantially the same as that of the 8x recording strategy. It is shortened according to the ratio of recording speed. On the other hand, according to the 4x special OPC strategy, a pulse for recording data of a short mark such as a “2T pattern” is shortened from 4 ns to 2 ns (that is, about 50 percent). In addition, the pulse for recording data other than the short mark portion such as “4T pattern” is adjusted so that the pulse width of the highest power portion is the same as or substantially the same as that of the 8x recording strategy. The pulse width is reduced according to the recording speed ratio.

That is, in any case, based on the special OPC strategy, the pulse width is set closer to the pulse width defined by the 8x recording strategy than the pulse width defined by the recording strategy used when recording original data. Changes. In particular, in the shortest pattern “2T pattern” data and other pattern data having the highest power, a laser beam having the same pulse width as the pulse width originally used for recording data at a recording speed of 8 ×. Is irradiated. More specifically, relatively short pattern data (for example, a so-called short mark portion such as “2T pattern”) is relatively shorter, and relatively long pattern data (for example, “11T pattern”) is The 4x special OPC strategy and the 6x special OPC strategy are set so as not to be shortened as the data of a relatively short pattern changes.

In this way, OPC patterns can be recorded at recording speeds of 4x and 6x using pulse widths that are the same, approximately the same as, or approximate to, the pulse shape defined by the 8x recording strategy. At this time, the peak power of the laser beam defined by the 8x recording strategy shown in FIG. 6A and the 4x special OPC strategy or 6x special OPC strategy shown in FIGS. 6B and 6C are used. The specified peak power of the laser beam is the same. Therefore, according to the special OPC processing using the 4x special OPC strategy or the 6x special OPC strategy, the optimum laser power of the 8x recording strategy can be determined according to the 8x recording speed used at the time of actual recording.

It should be noted that the special OPC strategy generated in this way does not necessarily allow the optimum laser power of the 8x recording strategy to be appropriately calculated depending on, for example, characteristics such as the recording sensitivity of the optical disc. Specifically, the β value or the modulation degree for realizing the optimum laser power in the 8x recording strategy may differ between the 8x recording strategy and the generated 4x special OPC strategy. When the special OPC process is performed using such a 4x special OPC strategy, the calculated optimum laser power may be different from the optimum laser power in the 8x recording strategy.

For this reason, the generated special OPC strategy is not used as it is in the actual special OPC processing, and typically, the adjustment of the recording power and the recording waveform that defines the special OPC strategy is performed by the adjustment operation described later. After being implemented, it is used for special OPC processing. Hereinafter, such a special OPC strategy before adjustment is referred to as a temporary special OPC strategy for convenience.

As described above, a 4x temporary special OPC strategy with an adjusted pulse width is generated. Subsequently, specifically, the special OPC strategy evaluation unit 354 performs an adjustment operation on the generated 4x temporary special OPC strategy. Such a temporary special OPC strategy adjustment operation will be described with reference to the flowchart of FIG.

First, trial writing of data is performed on the outer peripheral side PCA 116 of the optical disc 100 using the generated 4x temporary special OPC strategy (step S201). At this time, the degree of modulation and β at the time of data recording are measured by the γ detector 356 and the β detector 357, respectively. Note that the position in the PCA of the optical disc 100 where the trial writing using the 4x temporary special OPC strategy is performed has a recording sensitivity difference from the position where the OPC process using the 8x recording strategy described above (step S104) is performed. Small is preferable. If the recording sensitivity difference is small, trial writing may be performed in the inner peripheral PCA 111.

Subsequently, the modulation degree in the recording with the detected temporary special OPC strategy is based on the modulation degree corresponding to the optimum laser power in the 8x recording strategy measured in step S105 (hereinafter referred to as a reference modulation degree as appropriate). It is determined whether or not the predetermined value (step S202). Here, the predetermined value typically means a value included in a predetermined range centered on the reference modulation degree, and is, for example, a value within 5% of the reference modulation degree. .

Here, when the measured modulation degree is larger than a predetermined range centered on the reference modulation degree (step S203: Yes), the special OPC strategy generation unit 353 sets the recording power of the 4x temporary special OPC strategy. Among them, the ratio of the normal recording power (that is, middle power) Pm to the peak power Pw at the time of recording is reduced by a predetermined amount (step S204). On the other hand, when the measured modulation degree is lower than the predetermined value (step S203: No), the ratio of the middle power Pm to the peak power Pw is increased (step S205). Thereafter, trial writing is performed again, the modulation degree is measured (step S206), and the process is looped until the modulation degree falls within the predetermined value shown in step S202.

The recording power adjustment based on β is performed in parallel with the modulation degree adjustment in steps S202 to S206. First, β in recording with the detected temporary special OPC strategy is a predetermined value based on β corresponding to the optimum laser power in the 8x recording strategy measured in step S105 (hereinafter referred to as reference β as appropriate). Whether it is a value or not is determined (step S207). Here, the predetermined value typically means a value included within a predetermined range centered on the reference β, and is, for example, a value within 5% of the reference β.

Here, when the measured β is larger than a predetermined range centered on the reference β (step S208: Yes), the special OPC strategy generation unit 353 uses the recording power in the 4x temporary special OPC strategy, The ratio of the space power Ps to the peak power Pw at the time of recording is reduced by a predetermined amount (step S209). On the other hand, when the measured β is lower than the predetermined value (step S208: No), the ratio of the space power Ps to the peak power Pw is increased (step S210). Thereafter, trial writing is performed again, β is measured (step S211), and looping is performed until β falls within the predetermined value shown in step S207.

Then, for the 4x temporary special OPC strategy whose recording power is adjusted, the pulse adjustment by the recording compensation is performed again on the recording waveform other than the short mark portion (step S212).

レーザー With this series of operations, the laser power and pulse width specified in the 4x temporary special OPC strategy are adjusted. Hereinafter, the 4x temporary special OPC strategy adjusted by such an operation will be referred to as a 4x special OPC strategy for convenience. An example of adjusting the 4x temporary special OPC strategy will be described in detail later.

After the adjustment of the 4x temporary special OPC strategy is completed and the 4x special OPC strategy is acquired, the 4x special OPC strategy is stored (step S108), and the 4x special OPC is performed at the 4x recording speed in the inner peripheral PCA 111. An OPC process using a strategy (that is, a special OPC process) is performed (step S109). By this special OPC process, the optimum laser power for recording data at a recording speed of 8x is calculated.

When the 4x special OPC strategy is stored in advance in the information recording apparatus 1 or the optical disc 100 (step S102: Yes), the stored special OPC strategy is acquired instead of generating the temporary special OPC strategy as described above. Is done.

However, the special OPC strategy acquired in this way may not necessarily be able to properly calculate the optimum laser power of the 8x recording strategy depending on characteristics such as the recording sensitivity of the optical disc. Specifically, the β value or the degree of modulation for realizing the optimum laser power in the 8x recording strategy may differ between the 8x recording strategy and the acquired 4x special OPC strategy. When the special OPC process is performed using such a 4x special OPC strategy, the calculated optimum laser power may be different from the optimum laser power in the 8x recording strategy. Therefore, in the present embodiment, the adjustment operation is also performed for the special OPC strategy acquired in this way. Hereinafter, the special OPC strategy acquired in this way is also referred to as a temporary special strategy for the sake of convenience.

First, the OPC process (that is, the special OPC process) is performed using the acquired 4x special OPC strategy (that is, the temporary special OPC strategy) at the recording speed of 4x in the outer peripheral side PCA 116 in the optical disc 100 (step S40). S111). At this time, the modulation degree and β value when the optimum laser power in the 4x provisional special OPC strategy is output, which is estimated by the optimum power estimation unit 359, is measured (step S112).

Subsequently, using the 8x recording strategy, the OPC process at the recording speed of 8x is performed in the outer peripheral PCA 116, and the optimum laser power in the 8x recording strategy estimated by the optimum power estimation unit 359 is output. The modulation factor and β value are measured (step S113).

Based on the measured modulation degree and β value, the 4x temporary special OPC strategy adjustment operation is performed in the same manner as the special OPC strategy adjustment operation described above (step S107). Then, the optimum laser power for performing data recording at the recording speed of 8x is calculated by the special OPC process (step S109) using the adjusted 4x special OPC strategy.

In the example described above, the case where the inner peripheral side PCA 111 cannot achieve the recording speed of 8x has been described as an example. However, the inner peripheral side PCA 111 performs OPC processing (that is, at least the data of the data) at the recording speed of 8x. Recording and reproduction) may be possible. In this case (step S101: Yes), the inner PCA 111 performs the OPC process at the recording speed of 8x using the generated 8x recording strategy (step S121). At this time, 8x recording strategy recording compensation may be performed from the obtained result (step S122). As a result, an 8x recording strategy capable of calculating the optimum laser power with higher accuracy can be acquired.

(5) Adjustment Example of Temporary Special Strategy Next, with reference to FIG. 7, an adjustment example of a 4x temporary special OPC strategy based on the β value will be described as an example of adjustment of the temporary special OPC strategy. FIG. 7 is a graph showing an example of the relationship between the optimum laser power obtained by the OPC process and the β value. The result of the OPC using the 4x temporary special OPC strategy at the recording speed of 4x (4x A graph of the result of OPC using a recording strategy at a recording speed of 8x (temporary special OPC: solid line portion) and a recording speed of 8x (8x recording OPC: one-dot broken line portion) is shown. FIG. 7A shows a case where the result of OPC using the 4x temporary special OPC strategy is not linear in the vicinity of the optimum laser power in the 8x recording strategy, and FIG. The case where the result of OPC using the 4x temporary special OPC strategy is linear in the vicinity of the optimum laser power in the recording strategy is illustrated.

First, description will be made with reference to FIG. The result of OPC using the 4x provisional special OPC strategy typically differs from the OPC performed using the recording strategy at the recording speed of 8x in the characteristic of recording power versus β value. For this reason, even if the OPC using the 4x provisional special OPC strategy is simply performed, the β value corresponding to the optimum laser power calculated by the OPC performed using the recording strategy at the recording speed of 8x is the reference value described above. It is different from β. Hereinafter, in each strategy, the β value that realizes the optimum laser power calculated by the OPC performed using the recording strategy at the recording speed of 8 × is referred to as a target β. That is, the target β in the 8x recording strategy becomes the reference β. Further, the difference between the targets β for each strategy (that is, in FIG. 7A, the difference between the target β of the 4 × provisional special strategy and the target β of the 8 × recording strategy) is referred to as Δ target β.

Therefore, as shown in the above steps S207 to S211, in the 4x temporary special OPC strategy, the target β measured at the time of recording with the 4x temporary special OPC strategy is within a predetermined range centered on the reference β. The recording power (that is, the ratio of the space power Ps to the peak power Pw) is adjusted. For example, in the example of FIG. 7A, since the target β measured during recording with the 4 × provisional special OPC strategy is larger than the reference β, the ratio of the space power Ps to the peak power Pw is adjusted to decrease. . By adjusting the recording power in this way, the result graph of OPC using the 4x temporary special OPC strategy is shifted to the right side in FIG. For this reason, the β value corresponding to the optimum laser power in the result of OPC using the 4 × provisional special OPC strategy approaches the target β (that is, the Δ target β decreases). As a result, according to the OPC process using the 4x temporary special OPC strategy adjusted in this way (that is, the 4x special OPC strategy), the 8x recording is performed in the recording power region equivalent to the optimum laser power of at least the 8x recording strategy. It is possible to realize a recording power vs. β value characteristic substantially equal to that when OPC is performed using a recording strategy at a speed.

Note that there is a possibility that an appropriate optimum laser power cannot be calculated in a portion where the relationship between the recording power calculation result by the 4x special OPC process and the corresponding β value is not linear. For this reason, in the 4x special OPC strategy, in an area where a recording power substantially equal to the optimum laser power at a recording speed of at least 8x is output, as shown in FIG. It is preferable to adjust so as to be a portion having linearity in the correspondence relationship.

According to the adjustment operation of the special OPC strategy in this embodiment, the target β at the recording speed of 4x is within a predetermined range (for example, within a range of about plus or minus 5%) based on the target β at the recording speed of 8x. The recording power is regulated as specified in the 4x special OPC strategy. Specifically, the β value is adjusted with respect to the recording power by adjusting the output of the space power Ps based on the peak power Pw among the plurality of recording powers defined in the 4x special OPC strategy as described above. Is done. That is, by adjusting the special OPC strategy, the value of the above-described Δ target β is adjusted to be further reduced.

Also, by adjusting the 4x special OPC strategy, it is possible to perform the OPC process so that the OPC result at the recording speed of the OPC result at the recording speed of 4x becomes substantially the same graph.

On the other hand, the recording power adjustment operation of the 4x temporary special OPC strategy using the modulation degree is also performed in the same manner based on the β value, and preferably the modulation degree for the optimum power by OPC using the 8x recording strategy is The reference modulation degree is approached. As shown in steps S202 to S206 in FIG. 4, by adjusting the output of the middle power Pm based on the peak power Pw, it is possible to suitably adjust the degree of modulation during data recording. In this embodiment, the modulation degree that realizes the optimum recording power at the recording speed of 8x is set as the reference modulation degree, and the modulation degree that realizes the optimum laser power at the recording speed of 4x is based on the reference modulation degree. The output of the middle power Pm is adjusted so as to be within a predetermined range (for example, within a range of about plus or minus 5%).

In this way, by adjusting the recording power on the generated 4x special OPC strategy (that is, 4x provisional special OPC strategy) based on the modulation degree and the β value, at least in the vicinity of the optimum power, 8x A special OPC strategy (that is, a 4x special OPC strategy) in which the characteristics of the recording power vs. β value (or modulation degree) are substantially the same as the OPC performed using the recording strategy at the recording speed of 4 can be obtained. . By performing OPC processing at a recording speed of 4x using such a 4x special OPC strategy, a laser beam having a recording power equivalent to the actual emission power at a recording speed of 8x and a pulse width equivalent to that is obtained. OPC processing can be performed. Accordingly, it is possible to reduce or eliminate an error in the optimum laser power due to a characteristic change between the current value input to the optical pickup 320 and the power of the laser beam actually emitted from the optical pickup 320. As a result, by recording the OPC pattern at a recording speed of 4x, the optimum laser power at the recording speed of 8x can be calculated appropriately and with high accuracy.

In particular, even when another information recording apparatus with different output power for performing the OPC process is used or when the output power is changed due to the aging of the optical pickup, the OPC process is performed using the 4x special OPC strategy. To achieve a recording power vs. β value characteristic that is roughly equivalent to that obtained when OPC is performed using a recording strategy at a recording speed of 8x in a recording power region equivalent to at least the optimum laser power of the recording strategy of 8x. I can do it. For this reason, the optimum laser power at the recording speed of 8x can be appropriately obtained by performing the OPC process at the recording speed of 4x by using the special OPC strategy without being affected by the characteristics such as the laser power in the information recording apparatus. It is possible to calculate.

Even if the method described in the present embodiment is not used, the OPC processing is performed using the 4x recording strategy without using the OPC strategy, and the optimum laser power at the recording speed of 8x can be calculated from the result. I can do it. However, in this case, since the 4x recording strategy is a strategy determined without considering the recording speed of 8x, the optimum recording power obtained by performing the OPC process using the 4x recording strategy is also 8x. The recording power at the time of recording data at a recording speed is not taken into consideration and is greatly different. Further, since the pulse width differs greatly between the recording speed of 4x and the recording speed of 8x, the influence of ringing on the emission waveform of the laser light is also different, and the accuracy of the OPC processing becomes unstable. For this reason, although it can be said that it is possible to calculate the optimum laser power as a prediction, the accuracy is not necessarily high depending on a change in characteristics or the like.

As described above, according to the information recording apparatus of this embodiment, even if the OPC process is not actually performed at the recording speed of 8x, if the OPC process is performed at a lower speed, for example, 4x, the 8x The optimum laser power at the recording speed can be calculated. In particular, as the recording speed increases, the rotation speed of the optical disc 100 increases accordingly. For this reason, the rotation speed cannot be realized especially on the inner circumference side of the optical disk, or even if the rotation speed is realized, the optical disk 100 may be damaged, the servo may become unstable, If the detection accuracy is lowered, there is a possibility that the OPC process cannot be performed appropriately. This embodiment solves such inconvenience, and even if the recording speed becomes high, if the OPC process is performed at a lower recording speed, the optimum laser power at the high recording speed can be calculated. Has advantages.

Further, according to the information recording apparatus of the present embodiment, when performing OPC processing (that is, special OPC processing) at a different recording speed that originally requires a special strategy, the special OPC strategy is changed from the original recording strategy. Can be generated. Further, it is possible to adjust the recording power and the recording waveform defined in the special OPC strategy that is generated or acquired from the memory or the like (that is, the temporary special OPC strategy). For this reason, special OPC strategy is not prepared in advance, in other words, special OPC processing can be performed even for unknown optical disks, and also for known optical disks for which special OPC strategies are prepared. It is possible to carry out a special OPC process with higher accuracy.

Furthermore, in this embodiment, the recording power defined in the special OPC strategy is adjusted for the special OPC strategy created or acquired. Specifically, the output of the space power Ps defined in the 4x special OPC strategy is adjusted so that the value of the target β becomes a predetermined value based on the target β at the recording speed of 8x. By adjusting in this way, special OPC processing using a recording sensitivity range substantially equivalent to that at the actual double speed recording such as 8x can be performed. This is effective in improving the calculation accuracy of the optimum laser power by the special OPC process.

On the other hand, the modulation degree corresponding to the optimum laser power by the 4x special OPC strategy is defined in the 4x special OPC strategy so that the modulation degree for realizing the optimum laser power at the recording speed of 8x becomes a predetermined value as a reference. The output of the middle power Pm is adjusted. In this way, by adjusting the output of the middle power Pm (and hence the average recording power) based on the target modulation degree, it is possible to prevent thermal change or damage of the recording film due to excessive recording power. Become.

In the above-described embodiment, the OPC process is performed at a slower recording speed of 4x in order to calculate the optimum laser power at a higher recording speed of 8x. In order to calculate the optimum laser power at the recording speed, it is natural that the OPC process may be performed at a higher recording speed of 8 × and using the 8 × special OPC strategy. That is, the optimum laser power at the 4x recording speed can be obtained by performing the OPC process at the 8x recording speed that is higher than the 4x recording speed at which data is actually recorded. In addition, in this case, since the OPC pattern can be recorded at a relatively high recording speed of 8 ×, there is an advantage that the time required for calculating the optimum laser power can be reduced.

In the above-described embodiments, the optical disc 100 that is a BD as an example of the information recording medium and the recorder according to the optical disc 100 as an example of the information recording apparatus have been described. However, the present invention is not limited to the optical disc and the recorder. The present invention can also be applied to various information recording media corresponding to high-density recording or high transfer rate and its recorder.

The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and information recording accompanying such changes is possible. An apparatus, an information recording method, a computer program, an information recording medium, and the like are also included in the technical scope of the present invention.

1 Information recording apparatus 100 Information recording medium 111 Inner peripheral side PCA
116 Outer peripheral side PCA
300 Information Recording Device 310 Spindle Motor 320 Optical Pickup 330 CPU
350 Signal recording / playback unit

Claims

Recording means for irradiating the information recording medium with laser light to record information on the information recording medium;
Using a recording strategy for recording the information at the first recording speed at the first recording speed, the target laser power of the laser beam and the asymmetry when recording the information using the target laser power First calculating means for calculating a value and a modulation degree;
Based on the recording strategy, it is used to calculate the optimum laser power of the laser beam when recording the information at the first recording speed at a second recording speed different from the first recording speed. Obtaining means for obtaining a special OPC strategy that defines the waveform of the laser beam;
(i) adjustment of the laser power defined in the special OPC strategy based on at least one of the asymmetry value and the modulation degree; and (ii) adjustment of the recording waveform defined in the special OPC strategy based on the recording speed. Adjusting means for performing
Second calculating means for calculating the optimum laser power using the adjusted special OPC strategy at the second recording speed;
An information recording apparatus comprising: control means for controlling the recording means to record the information at the first recording speed using the calculated optimum laser power and the recording strategy.
2. The information recording apparatus according to claim 1, wherein the adjusting means adjusts a pulse width corresponding to a code other than a short mark in a recording waveform defined in the special OPC strategy.
The adjusting means includes (i) adjusting a ratio of a space power to a peak power defined in the special OPC strategy based on the asymmetry value, and (ii) a peak defined in the special OPC strategy based on the modulation degree. The information recording apparatus according to claim 1, wherein at least one of adjustment of a ratio of middle power to power is performed.
2. The information recording apparatus according to claim 1, wherein the first recording speed is higher than the second recording speed.
Acquiring medium information specifying the information recording medium, and (i) storing the medium information and the special OPC strategy related to the information recording medium, and (ii) recording on the information recording medium Storage means for performing at least one of them,
The acquisition unit acquires a special OPC strategy stored corresponding to the medium information when the medium information acquired from the information recording medium matches the medium information stored in the storage unit. The information recording apparatus according to claim 1.
A recording step of irradiating the information recording medium with laser light to record information on the information recording medium;
Using a recording strategy for recording the information at the first recording speed at the first recording speed, the target laser power of the laser beam and asymmetry when recording the information using the target laser power A first calculation step of calculating a value and a modulation degree;
Based on the recording strategy, it is used to calculate the optimum laser power of the laser light when recording the information at the first recording speed at a second recording speed different from the first recording speed. An acquisition step of acquiring a special OPC strategy that defines the waveform of the laser beam;
(i) adjustment of the laser power defined in the special OPC strategy based on at least one of the asymmetry value and the modulation degree; and (ii) adjustment of a recording waveform defined in the special OPC strategy based on the recording speed. An adjustment process to perform
A second calculation step of calculating the optimum laser power using the adjusted special OPC strategy at the second recording speed;
A control step of controlling the laser power of the laser light in the recording step so as to record the information at the first recording speed using the calculated optimum laser power and the recording strategy. A characteristic information recording method.
Using a recording means for recording information on the information recording medium by irradiating the information recording medium with laser light, and a recording strategy for recording the information at the first recording speed at the first recording speed, Based on the recording strategy, first calculation means for calculating a target laser power of the laser light, an asymmetry value and a modulation degree when recording the information using the target laser power, and the first recording speed are: Obtain a special OPC strategy that defines the waveform of the laser beam used to calculate the optimum laser power of the laser beam when recording the information at the first recording rate at a different second recording rate. Acquisition means; (i) adjustment of laser power defined in the special OPC strategy based on at least one of the asymmetry value and the modulation factor; and (ii) the recording speed And adjusting means for adjusting the recording waveform defined in the special OPC strategy based on the degree, and using the special OPC strategy adjusted at the second recording speed, a second laser beam for calculating the optimum laser power. Provided in an information recording apparatus comprising: calculating means; and control means for controlling the recording means so as to record the information at the first recording speed using the calculated optimum laser power and the recording strategy. A recording control computer program for controlling a computer,
A computer program that causes the computer to function as at least part of the recording unit, the first calculation unit, the second calculation unit, the acquisition unit, the adjustment unit, and the control unit.
An information recording area for recording information;
A control area for recording a recording strategy that defines a waveform of a laser beam used for recording the information at a first recording speed;
The information recording area includes a portion where the information can be recorded at the first recording speed and a portion where the information can be recorded at a second recording speed different from the first recording speed. A characteristic information recording medium.