JP2007109306A - Optical disk recording method, optical disk recording device, and optical disk recording program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that reproduction failure may occur due to degradation of a recording and reproduction state unless optimum recording is strictly carried out when recording is performed to a 1st recording layer of an optical disk with two or more recording layers. <P>SOLUTION: In once test writing, the ratio of erasing power to writing power is fixed to a predetermined value and a test signal is recorded on the optical disk with the writing power changed variously; the recorded test signal is reproduced and values concerning a modulation factor and asymmetry of the reproduced signal are detected; and the writing power is determined so that the value concerning a modulation factor near a preset value can be obtained, and the erasing power is determined so that the value concerning the asymmetry near a preset value can be obtained; and actual recording is carried out by controlling the power of a light beam by combining each determined value of the writing power and the erasing power. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc recording method, an optical disc recording apparatus, and an optical disc recording apparatus for performing trial writing in a trial writing area of an optical disc in order to obtain an optimum recording power of a light beam for recording information on a rewritable optical disc having a plurality of recording layers, The present invention relates to an optical disc recording program.

  Currently, DVD-R discs, which are write once optical discs according to the DVD (Digital Versatile Disc) standard, and DVD-RW discs, which are rewritable optical discs, are widely used. FIG. 18A schematically shows a cross-sectional structure of a DVD-R disc or DVD-RW disc having only one recording layer. In the figure, an optical disc 100 has a power calibration area (PCA) 101, a recording management area (RMA) 102, and a lead-in area (Lead-In) from the inner periphery toward the outer periphery. 103, a data area 104, and a lead-out area 105.

  The PCA area 101 and the RMA area 102 constitute an R information area 106. The data area 104 is an area where user data is recorded. The lead-in area 103 and the lead-out area 105 are buffer areas provided for overrun of the recording / reproducing head (optical pickup) when accessing the data area 104. A part of the lead-in area 103 as shown in FIG. 18B is called a control data zone. There, information on the entire optical disc such as the size of the optical disc and reference conditions for recording such as recording power and recording waveform pattern are recorded in advance when the optical disc is manufactured.

  The optical disc drive apparatus trial-writes a predetermined signal while changing the recording conditions on the target optical disc 100 before starting the main recording on the data area 104 of the DVD-R disc or the DVD-RW disc, and performs trial writing. The optimum recording condition is acquired based on the characteristics of the reproduction signal acquired by reproducing the recorded area, and the main recording is performed under the optimum recording condition. Thereby, good recording quality can be obtained.

  Obtaining the optimum recording condition based on the reproduction signal from the trial-written area in this way is called OPC (Optimum Power Control), but the PCA area 101 in FIG. 18A is prepared for performing this OPC. It is an area that has been. Further, the RMA area 102 in FIG. 18A is an area in which recording management information for managing the transition of the recording state of the lead-in area 103, the data area 104, and the lead-out area 105 and OPC information is recorded. is there. In the RMA 102, recording is performed in units of RMD (Recording Management Data) blocks that are blocked and error-correction-coded in the same manner as user data in the data area 104.

  As shown in the perspective view of FIG. 19, the DVD-R disc and the DVD-RW disc have a groove track 201 as an information track on a recording layer and a land track 202 for guiding a light beam 203 to the groove track 201. Are alternately formed in the radial direction of the optical disk. Further, on the land track 202, address information and the like on the optical disc are recorded as land pre-pits (LPP) 204 at the pre-format stage when the optical disc is manufactured (see, for example, Patent Document 1). Recording on a DVD-R disc or a DVD-RW disc is performed based on the LPP 204. In addition to the address information, the LPP stores reference conditions for recording such as recording power and recording waveform pattern.

  Now, the capacity that the user wants to record is increasing year by year, and DVD-R discs and DVD-RW discs having two recording layers are being developed to meet this demand. FIG. 20 is a schematic cross-sectional view of an example of the dual-layer DVD-R disc and DVD-RW disc. As shown in the figure, in a single-sided dual-layer DVD-R disc or DVD-RW disc, a first recording layer 301 and a second recording layer 302 are laminated in the optical axis direction of a light beam 402 during recording and reproduction. Thus, the light beam 402 is condensed on the first recording layer 301 by the objective lens 401 or transmitted through the first recording layer 301 and condensed on the second recording layer 302.

  The recording area of the first-layer recording layer 301 closer to the optical pickup (light beam 402) has a PCA area 311, an RMA area 312, a lead-in area (Lead-In) 313, data, from the inner circumference toward the outer circumference. The area is divided into an area (Data Area) 314 and an intermediate area (Middle Area) 315. The recording area of the second recording layer 302 includes a PCA area 321, an RMA area 322, a lead-out area 323, a data area 324, and an intermediate area from the inner periphery toward the outer periphery. It is divided into an area (Middle Area) 325.

  That is, in the first recording layer 301, the lead-out area 105 is changed to the intermediate area 315 with respect to the single-layer DVD-R disc shown in FIG. The second recording layer 302 has substantially the same structure as the first recording layer 301, but a lead-out area 323 is provided instead of the lead-in area 313. The first recording layer 301 is recorded from the inner peripheral side toward the outer peripheral side, and the second recording layer 302 is recorded from the outer peripheral side toward the inner peripheral side.

Before the main recording is performed in the data area 314 of the first recording layer 301, OPC is performed in the PCA area 311 of the first recording layer 301, and before the main recording is performed in the data area 324 of the second recording layer 302, the second recording layer 301 is recorded. OPC is performed in the PCA area 321 of the first recording layer 302. The usage of the PCA area is determined as shown in FIG. That is, for the PCA area 311 of the first recording layer 301, trial writing is performed from the area boundary on the outer peripheral side to the inner peripheral side. On the other hand, for the PCA area 321 of the second recording layer 302, trial writing is performed from the area boundary on the inner circumference side to the outer circumference side. At this time, the area of the first recording layer 301 located on the incident side of the second-layer PCA area 321 is left unrecorded. Accordingly, when the OPC process is performed a plurality of times and the radial distance between the recorded small area of the PCA area 311 and the recorded small area of the PCA area 321 becomes a certain distance or less, the further OPC process is performed. Cannot be done.
Since the DVD-RW disc is a rewritable medium, in this case, the OPC process can be performed again by DC erasing the recorded area in the PCA area.

  Between the optimum recording power of the second recording layer 302 obtained in the unrecorded state of the first recording layer 301 and the optimum recording power of the second recording layer 302 obtained in the recording state of the first recording layer 301. Is known to have a difference inherent to each optical disc. Recording to the data area 324 of the second recording layer 302 is determined to be performed through the recorded first recording layer 301. Therefore, the value of this power difference is pre-recorded on each optical disc. The optical disc apparatus records the first recording layer 301 by subtracting the value of the pre-recorded power from the optimum recording power of the second recording layer 302 obtained when the first recording layer 301 is not recorded. The optimum recording power of the second recording layer 302 in the state is calculated.

  By the way, a DVD-RW disc is an optical disc that can be rewritten a plurality of times with respect to a DVD-R disc that can be recorded only once and cannot be rewritten. Usually, the number of rewritable times is several thousand times or more. The DVD-RW disc uses a phase change material. For recording on a DVD-RW disc, a light beam whose recording power changes into ternary values Pw, Pe, and Pb as shown in FIG. 2, for example, is used. Pw is a writing power, and this power changes the state of the recording film from the crystalline state to the amorphous state to form a mark. Pe is an erasing power, and the power Pe returns from the amorphous state to the crystalline state, and the old mark is erased (overwritten). Pb is a bottom power, which corresponds to the power at the bottom of a divided pulse obtained by so-called pulse division recording, and functions to prevent heat from being diffused by light beam irradiation during recording.

  As described in Patent Document 2, an asymmetry value β (an index representing the non-target property of the HF signal) or a modulation degree is used as a characteristic parameter for determining the quality of a recording state when performing OPC of a phase change optical disc. The value γ obtained from is used.

  In Patent Document 2, first, the erasing power and the bottom power are fixed, the writing power is changed, the test recording signal is recorded, the portion is reproduced, and the characteristic parameters for judging the quality of the recording state are measured. Thus, the optimum writing power is obtained. Next, use the writing power, fix the bottom power, change the erasing power, record the test recording signal, and reproduce the portion to measure the characteristic parameters that determine the quality of the recording state Then, the optimum erasing power is obtained. Finally, the write power and erase power are used, the bottom power is changed, the test recording signal is written, the portion is reproduced, and the characteristic parameters for judging the quality of the recording state are measured, thereby determining the optimum bottom. Ask for power. A method is described in which the writing power, the erasing power, and the bottom power obtained as described above are obtained and the main recording is performed in the data area.

  Here, it is described that β or γ or an error rate is used as a characteristic parameter for determining the quality of the recording state. Since the optimum recording state is the recording state in which the error rate is finally the best, it seems that the error rate itself may be used as a characteristic parameter for determining the quality of the recording state. However, since an error rate that can withstand practical use cannot be measured unless a large amount of data is actually recorded, it takes a long time to use for OPC and consumes a lot of PCA area. It is not actually used as a characteristic parameter.

JP-A-10-293926 Japanese Patent No. 3259642

  In a DVD-RW disc having two recording layers, which is currently under development, the recording film of the first recording layer is changed to a single-layer DVD-RW disc in order to transmit the recording laser light to the second recording layer. It needs to be considerably thinner than that. Therefore, it is difficult to manage the recording conditions as compared with a single-layer DVD-RW disc. In our research, it has been found that if the optimum recording is not strictly performed, particularly in the first recording layer, the recording / reproducing state deteriorates, and many errors occur during reproduction or defective reproduction occurs.

  As shown in FIG. 12, the dual-layer DVD-RW disc (double-layer optical disc) has an allowable ε (ratio of the erasing power Pe to the write power Pw) compared to the single-layer DVD-RW disc (single-layer optical disc). The range is known to be very narrow. Therefore, it is necessary for the recording apparatus to record information after determining the optimum Pw and the optimum Pe with high accuracy.

  It has also been found that the recording / reproducing characteristics change with the number of recordings. Here, the number of times of recording is the first time when recording on a new optical disk shipped from the factory for the first time, and then the second time when recording again on the recorded portion. For example, even when DC erasure is performed between the first time and the second time, the recording / reproducing state of the second recording is greatly different from the first time. FIG. 22 shows the measurement results of the number of times of recording and the reproduction error rate when recording is performed using the same recording conditions. As can be seen from the figure, the error rate at the time of the second recording is relatively poor, and the reproduction error rate is relatively good for the 1000th time and after the 10th time. 23A and 23B show measurement results of the write power Pw and the reproduction error rate, and measurement results of the erase power Pe and the reproduction error rate. As can be seen from the figure, the reproduction error rate greatly changes with the change in the write power Pw or the erase power Pe. It can also be seen that there is a difference between the optimum writing power Pw or erasing power Pe at the first recording and the optimum writing power Pw or erasing power Pe at the second recording.

  Based on the above knowledge, the present invention is a recording such as the first recording layer (layer closer to the light beam) of an optical disc having a plurality of recording layers (for example, a DVD-RW disc having two recording layers). It was created for the purpose of performing good recording on a recording layer having a characteristic with a narrow power margin. Specifically, in the first trial writing to the first recording layer, the erasing power is written. The test signal is recorded while changing the write power stepwise with a constant ratio to the write power, and the recorded test signal is reproduced, and the values related to the modulation degree and asymmetry of the reproduction signal are detected simultaneously. An optical disc that determines the writing power so as to obtain a modulation degree close to a preset value and at the same time determines the erasing power so that a value relating to asymmetry close to the preset value is obtained Recording method, its recording device, and to provide the recording program.

In order to solve the above-described problems, the present invention provides an optical disc recording method, an optical disc recording apparatus, and an optical disc recording program having the configurations of (1) to (3).
(1) Write power for forming marks by changing the state of the recording film from the crystalline state to the amorphous state, and erasing power for returning from the amorphous state to the crystalline state and erasing old marks to form a mark non-formation section And rewritable optical disc recording in which new information is written while erasing old information recorded on the optical disc by using a light beam in which the bottom power of the divided pulse in the mark formation section by pulse division recording is set In the method
In one trial write, the test signal is recorded on the optical disc by changing the write power in various ways by fixing the ratio of the erase power and the write power to a predetermined value, and the recorded test signal is reproduced. In addition, the modulation power and the asymmetry value of the reproduction signal are simultaneously detected to determine the writing power so as to obtain a value related to the modulation degree close to the preset value, and at the same time, the asymmetry close to the preset value. Determining an erasing power so as to obtain a value according to
And a step of performing actual recording by controlling the power of the light beam by a combination of the determined values of the writing power and the erasing power.
(2) Write power for forming a mark by changing the state of the recording film from a crystalline state to an amorphous state, and an erasing power for forming an unmarked section by erasing an old mark by returning from the amorphous state to the crystalline state And rewritable optical disc recording, in which new information is written while erasing old information recorded on the optical disc, using a light beam in which the bottom power at the bottom of the divided pulse in the mark formation section by pulse division recording is set In the device
In one trial write, the test signal is recorded on the optical disc by changing the write power in various ways by fixing the ratio of the erase power and the write power to a predetermined value, and the recorded test signal is reproduced. In addition, by simultaneously detecting the modulation level and the asymmetry value of the reproduction signal, the writing power is determined so as to obtain a value related to the modulation level close to the preset value, and at the same time, the asymmetry close to the preset value. Means for determining the erasing power so as to obtain a value according to
An optical disk recording apparatus comprising: a recording unit that performs actual recording by controlling the power of a light beam by a combination of the determined values of the writing power and the erasing power.
(3) Write power for forming marks by changing the state of the recording film from the crystalline state to the amorphous state, and erasing power for returning from the amorphous state to the crystalline state and erasing old marks to form a mark non-formation section And a recording means for performing a recording process of writing new information while erasing old information recorded on the optical disk using a light beam in which the bottom power of the divided pulse in the mark formation section by pulse division recording is set A rewritable optical disc recording program for executing a control means for controlling
In one trial write, the ratio of the erase power and the write power is fixed to an appropriate value, and the test signal is recorded on the optical disc by changing the write power in various ways, and the recorded test signal is reproduced. Then, the value related to the modulation degree and asymmetry of the reproduction signal is detected at the same time to determine the writing power so as to obtain a value related to the modulation degree close to the preset value, and at the same time, close to the preset value. Determining an erasing power so that a value relating to asymmetry is obtained;
An optical disc recording program comprising the step of performing actual recording by controlling the power of a light beam with a combination of the determined values of the writing power and the erasing power.

In the rewritable type optical disc having a plurality of recording layers (recording films), the present invention can provide the optimum write power Pw in the modulation degree and asymmetry particularly when performing OPC of the recording layer having a characteristic with a narrow recording power margin. Simultaneously detecting such a value and determining the optimum write power from the value related to the degree of modulation and also determining the optimum erase power from the value related to asymmetry, so that only one trial write is required and the time required for OPC is reduced. Is possible.
Also, since the optimum values are derived for each of the writing power and erasing power, the value of ε recommended by the optical disc manufacturer described in the LPP or control data of the optical disc is shifted between production lots or the recording device Even when the optimum value deviates from the value recommended by the optical disc manufacturer due to variations in the optical disc, the optimum writing power and erasing power can be accurately set by the OPC of the present invention.

  As described above, the present invention provides a recording power such as the first recording layer (layer closer to the light beam) of an optical disc having a plurality of recording layers (for example, a DVD-RW disc having two recording layers). It was created for the purpose of performing good recording on a recording layer having a narrow margin characteristic. Specifically, in the first trial writing to the first recording layer, the erasing power and writing are performed. The test signal is recorded while changing the write power stepwise with a constant ratio with the power, the recorded test signal is reproduced, and the value relating to the modulation degree and asymmetry of the reproduced signal is detected simultaneously, Optical disc recording that determines write power so as to obtain a modulation factor close to a preset value and at the same time determines erase power so that a value related to asymmetry close to a preset value is obtained Law, the recording apparatus, there is provided the recording program.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of a recording / reproducing system including an embodiment of an optical disk recording apparatus according to the present invention. In the figure, the recording / reproducing system includes a host device 10, an optical disc device 20 which is an embodiment of the optical disc recording device of the present invention, and a single-sided dual layer having two recording layers as shown in FIG. DVD-RW disc 30. The host device 10 instructs the optical disc device 20 to record or reproduce the DVD-RW disc 30. The host device 10 is, for example, a personal computer. The host device 10 and the optical disk device 20 may be housed in the same housing. Such a form is employed in an optical disc recorder, for example. The DVD-RW disc 30 is loaded in the optical disc apparatus 20.

  The optical disk apparatus 20 is connected to the system controller 21 for controlling the entire apparatus, the recording / reproducing circuit 22 for recording and reproducing on the single-sided dual layer DVD-RW disk 30, and the recording / reproducing circuit 22 to emit and reflect the light beam. An optical pickup 23 for receiving a beam, a program memory 24 in which a control program for the system controller 21 is stored, a data memory 25 for temporarily storing data to be recorded on and reproduced from the DVD-RW disc 30, and a configuration thereof It comprises an internal bus 26 that connects elements, an IF 27 that interfaces the host device 10 with the internal bus 26, and a recording state detection circuit 28. The recording / reproducing circuit 22 and the optical pickup 23 are a recording unit for recording trial information and management information on a single-sided dual-layer DVD-RW disc 30 (an optical disc having a plurality of recording layers), and a reproducing unit for information recorded on the optical disc. Function as. The recording state detection circuit 28 functions as a means for performing measurement for calculating a characteristic parameter for determining whether the recording state is good or not when reproducing the portion where the trial writing has been performed. The measurement value measured by the recording state detection circuit 28 is sent to the system controller 21 via the internal bus 26, and the system controller 21 performs an operation using the measurement value according to the contents of the program memory 24 to calculate a characteristic parameter. The recording condition is determined from the calculation result.

  The single-sided dual-layer DVD-RW disc 30 is a phase change type recording medium, and records information by reversibly changing a crystalline phase and an amorphous phase. As shown in FIG. 2, actual recording is performed by using a light beam as a light emission waveform of a multi-pulse train. The drive pulse of the light beam is a pulse modulated by recording data (recording data, NRZI data). For example, in the period of certain NRZI data shown in the figure, a drive pulse as shown in the figure is generated.

  In FIG. 2, “Pw” is a level as write power, “Pe” is a level as erase power, and “Pb” is a level as bottom power. Further, “T” in FIG. 2 is a channel clock period, and “Ttop” and “Tmp” are pulse periods of write power. As can be seen from FIG. 2, the drive power of the erase power Pe is generated during the low level period of the NRZI data, while the write power Pw and the bottom power Pb alternately appear during the high level period of the NRZI data. It becomes.

  As described above, during the high level period of the NRZI data, the write power of the level Pw and the bottom power of the level Pb are alternately output, so that the condition of the phase change type recording medium is changed by the rapid cooling condition of heating → cooling. An amorphous phase is formed in the recording layer (mark formation section), and during the low level period of the NRZI data, a crystalline phase is formed in the recording layer of the phase change recording medium due to a slow cooling condition only by heating with the erase power of level Pe. Formed (unmarked section).

  In the data area or the like, direct over recording is used in which recording is performed on a recorded small area with a similar light emission waveform. On the other hand, in the PCA area, a technique is used in which OPC processing is performed by performing DC erasure with a predetermined erasing power after performing DC erasure on a small area once trial-written. This is because the optimum recording power may not be accurately obtained in direct over recording. When user data or the like is recorded in the data area, recording is started from the first recording layer, and recording to the second recording layer is started after recording of the first recording layer is completed. Recording on the second recording layer is performed such that the recording light beam passes through the recorded area of the first recording layer.

  A specific example of the recording state detection circuit 28 is shown in FIG. A reproduction signal obtained by reading the recording signal of the DVD-RW disc 30 with the light beam emitted from the optical pickup 23 is output from the optical pickup 23 to the recording / reproducing circuit 22 and the recording state detection circuit 28. What is input to the recording state detection circuit 28 is an HF (High Frequency) signal in the reproduction signal RF. The HF signal is input to the peak level detection circuit 43 in FIG. The output of the peak level detection circuit 43 is A3. The peak level detection circuit 43 detects the + side peak of the HF signal by analog processing.

  Further, the HF signal is cut by a high-pass filter 40 in FIG. 3 to obtain a signal as shown in FIG. The output of the high pass filter 40 is input to a peak level detection circuit 41 and a bottom level detection circuit 42. The outputs of the peak level detection circuit 41 and the bottom level detection circuit 42 are A1 and A2, respectively. The peak level detection circuit 41 and the bottom level detection circuit 42 detect the + side peak and the − side peak of the HF signal from which the DC component is cut, by analog processing, respectively. The data A1 to A3 are sent to the system controller 21, and the data A1 to A3 are used to perform calculations for obtaining characteristic parameters in the system controller 21. One of the characteristic parameters is a value β indicating the degree of asymmetry of the HF signal. β is obtained by the following calculation.

       β = (A1 + A2) ÷ (A1-A2)

  In a single-sided dual-layer DVD-RW disc, asymmetry characteristics are not linear when recording is performed with a fixed ratio of write power and erase power, as shown in FIG. 11, and the maximum value is near the optimum recording power at which jitter is lowest. Indicates. When the writing power is low, the asymmetry is shallow, and the asymmetry becomes shallow even with a high recording power near the optimum recording power. From this characteristic, there is a method for setting the recording power at which asymmetry or β is near the maximum value to the optimum power. Further, as another method for determining the quality of the recording state by asymmetry, there is a method using the following parameter Δβ obtained from the characteristic of β.

Δβ = (dβ / dPw) × (Pw / β)
That is, the parameter Δβ is obtained by differentiating the characteristics of asymmetry β.
Since Δβ has a linear characteristic as shown in FIG. 11, it is easy to obtain the target recording power.

  Although the asymmetry of the parameter representing the non-target property of the HF signal is omitted in the description of the β value, the same detection and effect can be expected. As the configuration for detecting this asymmetry, the β value detection configuration and the modulation degree detection configuration can be used. That is, the asymmetry value is calculated by the following equation using the signal A1, the signal A2, and the signal A3.

Asymmetry = [(I14H + I14L) − (I3H + I3L)] /
2 [(I14H-I14L)]
The signal I14H, the signal I14L, the signal I3H, and the signal I3L in the above equations are expressed by the following equations.
I14H = A3
I14L = A3- (A1-A2)
I3H = A3
I3L = A3- (A1-A2)

  When this detection is performed, recording is performed in a region from a predetermined address in the OPC region while alternately outputting a recording waveform pattern of test recording, for example, a single pattern of 3T and 14T as a set. When DC erasing power is applied to the area from the same address, recording is performed while changing the power step by step for each set. Next, when the area from the same address is reproduced to detect the recording state, the level of each HF signal is reproduced at the timing corresponding to the writing area of 3T and 14T to detect the signal A1, the signal A2, and the signal A3. Then, the above calculation can be realized.

One of the other characteristic parameters is a value m indicating the modulation degree of the HF signal. The degree of modulation m is obtained by the following calculation.
m = (A1-A2) ÷ A3

  The modulation degree m changes according to the write power Pw as shown in FIG. In general, when the writing power Pw is low, the amplitude of the reproduced HF signal is small, so the modulation degree m is small. As the writing power Pw increases, the amplitude of the reproduced HF signal increases, so that the modulation degree m increases. When the write power Pw increases to some extent, the modulation degree m becomes saturated. Since there are few reproduction errors when recording is performed with the writing power Pw at the beginning of saturation, the writing power value at that time can be determined as the optimum writing power Pwo.

As another method for determining the quality of the recording state based on the modulation degree, there is a method using the following parameter γ obtained from the characteristic of the modulation degree m.
γ = (dm / dPw) × (Pw / m)

  That is, the parameter γ is obtained by differentiating the characteristic of the modulation degree m. γ also varies with the write power Pw as shown in FIG.

  When all the OPC area is used and there is no free area, the optimum erase power is continuously emitted with DC (hereinafter referred to as DC erase), and the mark recorded by trial writing is erased so that it can be used again for OPC. become. When all of the data is recorded in the OPC area and DC erasure is repeated many times, in the case of the first layer of the RW double-layer optical disc, as shown in FIG. 13, β representing the asymmetry value is between 1 to 6 recording times. It changes a lot. In this case, it is difficult to obtain the optimum power using β as an index, but FIG. 14 shows the power characteristics of asymmetry with respect to the number of repeated recordings. In FIG. 14, DOW0 indicates the first recording, DOW1 indicates the overwrite once, and DOW10 indicates the tenth overwrite. Although the absolute value of the asymmetry varies depending on the number of recordings, the recording power near the maximum value of the asymmetry is less affected by the number of recordings. Further, as shown in FIG. 15, it was found that the power characteristic of γ obtained by differentiating the modulation degree is less affected by the number of recordings.

  In the present invention, OPC is performed using the characteristics of γ and β maximum values, which are less affected by the number of repeated recordings. The test writing is performed only once, and the value related to the modulation factor and asymmetry is detected at the same time. Γ is calculated from the modulation factor and used to determine the writing power, and the maximum value of β or the derivative value of β is calculated from the asymmetry. Used to determine the erase power.

  The optical disk apparatus 20 as an embodiment of the optical disk recording apparatus of the present invention shown in FIG. 1 performs the operation of any one of the following embodiments according to a program stored in the program memory 24. There is a feature. Moreover, the DVD-RW disc 30 which is an embodiment of the optical information recording medium of the present invention is pre-recorded with data for performing the operation of any one of the embodiments described below. And / or an area for storing data is secured.

  FIG. 6 shows the R information area of the single-sided dual-layer DVD-RW disc 30 for explaining the test writing operation of the optical disc recording apparatus according to the first embodiment of the present invention. FIG. 6A shows the state of the R information area of a new optical disc.

  When the DVD-RW disc 30 is loaded into the optical information recording device 20 or when an instruction is received from the host device 10, the optical information recording device 20 performs an OPC operation. The operation when performing OPC in the PCA area 311 of the first recording layer 301 will be described with reference to the flowcharts of FIGS.

  (S1) When the OPC operation is started, first, the latest RMD of the DVD-RW disc 30 is read to obtain the next area after the small area used in the previous OPC operation. In the case of the new optical disk of FIG. 6A, since there is no small area used in the previous OPC, the first small area used in the PCA area 311, that is, the outermost small area in the PCA area 311 is used. To do. Access to the small area is performed based on address information recorded as LPP.

Next, as shown in FIG. 9, the test power of the predetermined test signal is written by changing the write power Pw to 10 levels (S3).
At this time, the bottom power Pb of the write pulse in FIG. 2 is fixed at a predetermined value, and the erase power Pe is changed with the write power as a value obtained by multiplying the write power by a predetermined value ε. For example, ε has a value of 0.5. As shown in FIG. 9, the range in which the write power is applied is referred to as the OPC range, and the central power that is the reference at this time is referred to as Pdef. For the OPC range, there are methods such as shaking in 10 steps in the range of + 40% and -30% with respect to Pdef, or shaking in increments of 1 mW in the range of +5 mW and -4 mW with respect to Pdef. It should be noted that the number of steps is not necessarily 10 and may be an appropriate number of steps.

  Next, while reproducing the small area written by trial (S4), the system controller 21 calculates γ for each writing power using the value measured by the recording state detection circuit 28 (S5). The write power Ptarget is determined such that the calculated value of γ is a predetermined set value and a value close to γtarget. Further, a value obtained by multiplying Ptarget by a predetermined coefficient ρ is set as the optimum write power Pwo (S6).

        Pwo = ρ × Ptarget

  γtarget is 1.5, for example, and ρ is 1.22, for example. As the ε, Pdef, γtarget, and ρ values, values recorded in advance in the LPP or the control data zone at the time of manufacturing the optical disk may be used, or each optical disk type commercially available in the nonvolatile memory in the optical information recording apparatus 20 may be used in advance. The measurement result may be stored and the value may be used.

  In Patent Document 2, it is described that an asymmetry value may be used as a characteristic parameter for obtaining an optimum value of write power. However, in the case of the first recording layer of a single-sided dual-layer DVD-RW disc. It is easier to obtain good characteristics by using the modulation degree. FIG. 10 shows a graph of the write power Pw and the values of γ and β obtained in our study. The values of γ calculated from the measured values are aligned on the curve throughout the OPC range. Therefore, it is possible to accurately determine the write power Ptarget at which the calculated γ is close to the value of γtarget.

  Next, β for each erasing power is calculated (S7). Further, the value of β is differentiated to calculate Δβ to determine an erasing power Peor that is close to a predetermined set value, Δβtarget (S8). Δβtarget has a value of 0, for example. As this value, a value recorded in advance in the LPP or the control data zone at the time of manufacturing the optical disk may be used, or a measurement result of each commercially available optical disk type is stored in advance in a nonvolatile memory in the optical information recording apparatus 20. However, the value may be used.

  Before the end of the OPC operation, the address information of the small area in the PCA area used this time is stored in the RMD and recorded in the RMA (S9). As the address information, a value recorded as LPP is used.

  In Patent Document 2, it is described that the degree of modulation may be used as a characteristic parameter for obtaining the optimum value of the erasing power Pe. However, in the case of a single-sided dual layer DVD-RW disc, an asymmetry value is used. Good characteristics can be obtained more easily. FIG. 11 shows a graph of the erase power Pe and the values of γ and β obtained in our study. The value of Δβ calculated from the measured value is on a straight line, and the target value can be easily obtained. Therefore, it is possible to accurately determine the erasing power Peor at which the calculated Δβ value is close to the target value Δβtarget. On the other hand, since the value of γ calculated from the measured value depends on Po, it is difficult to accurately determine Peor using the value of γ. When the optimum erasing power Peor is determined experimentally by using the value of γ, there are many cases where it deviates from the optimum value.

  FIG. 16 to FIG. 17 show the results of comparing the errors in the write power and the erase power with respect to the proper value when ε is obtained based on γ and Δβ in the state where the value of ε is shifted to the proper value ± 10%. . In the modulation power method using γ as an index, the writing power has a smaller error of ε standard value ± 10%, but in the asymmetry method using Δβ as an index, the error is larger at an ε standard value of −10%. On the other hand, the erasing power is asymptotically −10% in the asymmetry method using Δβ as an index, and there are few errors. Therefore, the writing power Pw is determined using the modulation degree, and the erasing power Pe is determined using asymmetry.

  When the OPC operation as described above is executed many times, the small area where trial writing has been performed in the PCA area increases as shown in FIG. 6B. As shown by an arrow 61 in FIG. 6B, the PCA area 311 of the first recording layer is used for OPC from a small area on the outer peripheral side. On the other hand, the PCA area 321 of the second recording layer is used for OPC from a small area on the inner peripheral side as indicated by an arrow 62.

  When the number of OPCs is further increased, the state of the PCA area becomes as shown in FIG. In FIG. 6C, the distance between the innermost radial position of the used area of the PCA area 311 of the first recording layer and the outermost radial position of the used area of the PCA area 321 of the second recording layer is as follows. It is less than the threshold value Wth. In such a state, there is no new small area that can be used for trial writing in the PCA area, so the optical information recording apparatus 20 DC erases the recorded small area. This may be performed based on a command from the host device 10 or may be performed automatically by the optical information recording device 20 without a command. Here, the PCA area 311 of the first recording layer is used for trial writing from the outermost address S to the position of the address A in the PCA area 311, and the values of the address S and the address A are used in the optical disc apparatus 20. Stored in the data memory.

In DC erasing, irradiation is performed while maintaining the recording power of the light beam at the erasing power. In the state where the DC erasure is completed, the PCA area is in an unrecorded state as in FIG.
In the OPC operation for the PCA area 311 of the next first recording layer, the PCA area 311 is used again from the outermost small area.

  FIG. 6D shows a state where the OPC operation is performed as described above, and there is no longer a small area that can be used for test writing. In the case of FIG. 6D, regarding the first recording layer PCA area 311, the area from the outermost address S to the small area at the address B in the PCA area 311 is used for test writing. From this state, the PCA area is DC erased.

  After the DC erasure, the small area on the outermost periphery of the PCA area 311 of the first recording layer is used again for OPC.

As described above, in this embodiment, the ratio of the write power and the erase power is made constant, the write power is changed, the test recording signal is written, the portion is reproduced, and the target modulation degree or target The write power for obtaining a value close to γ is obtained, and the write power at the time of recording in the data area is determined from the value. Next, an erasing power capable of obtaining a value close to the target asymmetry value is obtained, and the erasing power at the time of recording in the data area is determined based on the erasing power. It is possible to decide by trial writing.
As shown in FIG. 8, the order of determining the writing power and the erasing power may be determined after the erasing power is determined.

  As for the shape of the recording pulse, a shape obtained by modifying the shape of FIG. 2 may be used.

  The present invention is not limited to the above embodiments and examples. For example, the recording medium to which the present invention is applied is also applicable to a rewritable optical disc in which three or more recording layers are laminated. be able to. The present invention also includes a computer program that causes a computer to execute each configuration of the optical information recording apparatus according to the above-described embodiments and examples. In this case, the computer program may be taken into the computer from a recording medium, or may be distributed via a communication network and downloaded to the computer.

1 is a block diagram of an optical disc recording / reproducing apparatus showing an embodiment of the present invention. It is an example of the light emission waveform of the laser beam used for recording of a rewritable optical disk. It is a block diagram of a recording state detection circuit that detects a value related to a modulation degree and a value related to asymmetry. It is a wave form diagram explaining the peak and bottom of the waveform from which the direct current component of the HF signal was cut. It is a graph explaining the calculated values of the degree of modulation m and γ detected by the recording state detecting means. The R information area | region of the single-sided double layer DVD-RW disc for demonstrating the test writing operation | movement of Example 1 of an optical information recording device is shown. It is an example of the flowchart of OPC operation | movement of this invention. It is another example of the flowchart of OPC implementation of this invention. It is a wave form diagram explaining the stepwise power change of recording laser power. It is a graph which shows an example of the value of write power Pw and (gamma), (beta). It is a graph which shows the correlation of the jitter of RW double layer disc, and asymmetry. It is the graph which compared the epsilon power margin of the RW double layer disc with the RW single layer disc. It is a graph which shows the rewrite frequency characteristic of asymmetry (beta) of a RW double layer disk. 6 is a graph showing the power margin and the number of rewrite times dependency of RW double-layer disc with respect to β. It is a graph which shows the power margin of RW double layer disc, and rewrite frequency dependence about (gamma). It is the graph which compared the writing power determination precision of the RW double layer disk by the method using a modulation degree, and the method using an asymmetry. It is the graph which compared the erasing power determination accuracy of the RW double layer disc by the method using the modulation degree and the method using asymmetry. It is a schematic diagram of a cross-sectional structure of a DVD-R disc or a DVD-RW disc having only one recording layer. It is a perspective view of a DVD-R disc or a DVD-RW disc. An example of schematic structure sectional drawing of a double layer disk is shown. It is a figure explaining the OPC recording order of the PCA area | region of a double layer disc. It is a graph which shows the rewriting characteristic of a RW disc about a reproduction error rate. It is a graph explaining the power margin and recording frequency of a RW double layer disc.

Explanation of symbols

20 Optical disk device (optical disk recording device)
21 System controller (control means)
22 Recording / reproducing circuit (recording means)
30 DVD-RW disc (optical disc)
301 First recording layer (recording film)
302 Second recording layer (recording film)
203 Light beam Pw Write power Pe Erase power Pb Bottom power

Claims (3)

Write power for forming a mark by changing the state of the recording film from the crystalline state to the amorphous state, erasing power for returning from the amorphous state to the crystalline state and erasing the old mark to form a mark non-forming section, and pulse division In the rewritable type optical disc recording method in which new information is written while erasing old information recorded on the optical disc using a light beam in which the bottom power of the divided pulse in the mark formation section by recording is set,
In one trial write, the test signal is recorded on the optical disc by changing the write power in various ways by fixing the ratio of the erase power and the write power to a predetermined value, and the recorded test signal is reproduced. In addition, by simultaneously detecting the modulation level and the asymmetry value of the reproduction signal, the writing power is determined so as to obtain a value related to the modulation level close to the preset value, and at the same time, the asymmetry close to the preset value. Determining an erasing power so as to obtain a value according to
And a step of performing actual recording by controlling the power of the light beam by a combination of the determined values of the writing power and the erasing power. Write power for forming a mark by changing the state of the recording film from the crystalline state to the amorphous state, erasing power for returning from the amorphous state to the crystalline state and erasing the old mark to form a mark non-forming section, and pulse division In a rewritable type optical disc recording apparatus in which new information is written while erasing old information recorded on the optical disc using a light beam in which the bottom power of the divided pulse in the mark formation section by recording is set,
In one trial write, the test signal is recorded on the optical disc by changing the write power in various ways by fixing the ratio of the erase power and the write power to a predetermined value, and the recorded test signal is reproduced. In addition, by simultaneously detecting the modulation level and the asymmetry value of the reproduction signal, the writing power is determined so as to obtain a value related to the modulation level close to the preset value, and at the same time, the asymmetry close to the preset value. Means for determining the erasing power so as to obtain a value according to
An optical disk recording apparatus comprising: a recording unit that performs actual recording by controlling a light beam power with a combination of the determined values of the writing power and the erasing power. Write power for forming marks by changing the state of the recording film from the crystalline state to the amorphous state, erasing power for returning from the amorphous state to the crystalline state and erasing old marks to form a mark non-formation section, and pulse division Controls a recording means for performing a recording process of writing new information while erasing old information recorded on the optical disk using a light beam in which the bottom power of the divided pulse in the mark forming section by recording is set. A rewritable optical disc recording program for executing a control means,
In one trial write, the ratio of the erase power and the write power is fixed to an appropriate value, the write power is changed variously, the test signal is recorded on the optical disc, and the recorded test signal is reproduced. Then, the value related to the degree of modulation and asymmetry of the reproduction signal is detected at the same time, the writing power is determined so as to obtain a value related to the degree of modulation close to the preset value, and at the same time, close to the preset value Determining an erasing power so that a value relating to asymmetry is obtained;
An optical disc recording program comprising the step of performing actual recording by controlling the power of a light beam by a combination of the determined values of the writing power and the erasing power.

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