KR20100061315A - Optical disk drive and write strategy decision method thereof - Google Patents

Abstract

The recording policy determination method of the optical disc drive which forms marks and spaces on the optical disc by laser light to display the recording information according to the present invention, and records or reproduces the information, corresponds to a power meter and a pulse width meter, Evaluating recording quality while varying on a two-dimensional matrix by combining at least two of the parameters defining pulses, and based on the evaluation result of the recording quality, the power meter and pulse width meter indicating a specific recording quality. Determining the parameters of the as a policy parameter.

Description

Optical disc drive and how to determine its recording policy {OPTICAL DISK DRIVE AND WRITE STRATEGY DECISION METHOD THEREOF}

 The present invention relates to an optical disc drive. More specifically, the present invention relates to a recording policy determination method and an optical disc drive that can determine in a short time and accurately an optimal recording policy for an optical disc drive whose recording policy is unknown.

The recording of information on the optical disc is performed by converting recording information given from a personal computer (PC) or the like into an EFM (Eight to Fouteen Modulation) signal. However, due to the difference in the composition of the optical disk used, the heat storage or cooling rate of the recording medium may vary. Since problems such as poor mark formation due to such a feature occur, even if the EFM signal is to be recorded as it is, a desired mark or space cannot be formed.

For this reason, a method of determining recording parameters (hereinafter, referred to as a write policy) unique to each optical disc to be used for the recording waveform as a reference and maintaining good recording quality is adopted. However, in order to determine the write policy peculiar to each optical disc to be used, there is a problem in that the burden on the developer is large, and in addition, it is difficult to cope with the write policy for the optical disc such as released after the end of the development of the disc drive.

In the policy adjustment of the rewritable disc, the recording characteristics are guaranteed from the direct overwrite (DOW (0)) starting from the unrecorded area to the direct overwrite (DOW (1000)) for 1000 duplicate input recordings. It is common to decide on a record policy. In normal cases, however, the recording characteristics and the recording conditions of the DOW 1 and the DOW 1000 are in a trade-off relationship with each other. For this reason, in the adjustment of a policy, it is important to balance each other efficiently in a short time.

By the way, in the present situation, if the recording characteristics of the direct overwrite (DOW (1)) which starts the adjustment of the policy on the basis of the disc recommendation policy or the existing adjustment completion policy and makes one duplicate input recording, the DOW ( 1000) recording characteristics are measured. As a result, when sufficient power margin cannot be secured, each pulse width, peak power, peak power, and erase power of the top pulse, the top cleaning pulse, the multi pulse, the last pulse, and the cooling pulse of the recording multi pulses The comparison value of is changed in a complex manner, a large amount of data of the recording characteristics of the DOW (0) to DOW (1000) are collected, and a policy for securing a sufficient power margin is selected and determined. For this reason, it is a fact that a huge amount of time is spent adjusting policy.

Japanese Laid-Open Patent Publication No. 2005-038473 discloses a light emission pattern in which the pulse setting means and the power setting means change the recording power in multiple stages at different pulse widths and every bottom power of a multi-pulse having recording power, erasing power and bottom power. Set, test writing to the optical disc, duplicate writing to the area, evaluate the reproduced signal with the reproduced signal evaluating means, determine the pulse width and the bottom power at which the power margin satisfies the reference value, There is a description that the recording power that can secure the recording characteristic of the center of the power margin under the following is called the optimum recording power.

Japanese Laid-Open Patent Publication No. 2006-260668 stores a table in which the optimal recording policy is set for each piece of identification information of an optical disc in the memory of the system controller. An average recording policy is set for an optical disc without identification information, and identification information is provided. In the case where data is recorded on an optical disc that does not exist, there is a description that the test data is recorded with an average recording policy, and a policy in which the detection rate of the synchronization signal is equal to or greater than a predetermined value is set as an optimal policy. By the way, Japanese Laid-Open Patent Publication No. 2005-038473 and Japanese Laid-Open Patent Publication No. 2006-260668 do not consider the recording quality of the DOW 1000.

In Japanese Laid-Open Patent Publication No. 2008-016164, the control unit reads the recommended recording policy in a predetermined area of an unknown disk, reads the corresponding correction parameter from the memory, corrects the recommended recording policy, and applies the recommended recording policy of completion of correction. On the basis of this, there is a description that the recording pattern is converted into a recording pulse, the OPC is executed, and then the actual data recording is started. However, it is difficult to guarantee all the disc qualities only by correcting the recommended recording policy.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a recording policy determination method and an optical disk drive that can accurately and optimally determine an optimal recording policy in a short time for an optical disk drive whose recording policy is unknown.

The recording policy determination method of the optical disk drive of the present invention corresponds to a power meter and a pulse width meter, and evaluates the recording quality while changing on a two-dimensional matrix by combining at least two of the parameters defining the recording multi-pulse. Wow; And based on the evaluation result of the recording quality, determining parameters of the power meter and pulse width meter indicating a specific recording quality as policy parameters.

In this embodiment, in the evaluating step, the recording power is obtained such that the recording quality of the direct overwrite which makes redundant input recording by changing the value of one of the at least two parameters is a desired limit value.

In this embodiment, in the determining step, any parameter whose recording power corresponds to a target value is determined as a policy parameter.

In this embodiment, the method further includes subtracting or adding a predetermined correction amount from any one of the parameters to determine the final policy parameter.

In this embodiment, the duplicated input recording is characterized in that one time.

An optical disc drive for forming a mark and a space indicating recording information on an optical disc by the laser light according to the present invention, and recording or reproducing the information corresponds to a power meter and a pulse width meter and defines a parameter for defining a multi-pulse for recording. A calculation process for evaluating recording quality while combining at least two of them on a two-dimensional matrix, and parameters representing a particular recording quality based on the evaluation result of the recording quality as policy parameters of the power system and pulse width meter. A write policy operation control unit for determining; And a recording pulse adjusting unit for generating and outputting a recording pulse string with reference to the determined policy parameter.

According to the present invention, it is possible to provide a recording policy determination method and an optical disk drive of an optical disk drive that can determine an optimal recording policy in a short time and accurately for an optical disk whose recording policy is unknown in the optical disk drive.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, embodiment of an optical disk drive recording policy determination method and an optical disk drive by this invention is demonstrated in detail.

Fig. 10 is a basic functional block diagram of an optical disc drive for executing the method according to the present invention. In Fig. 10, the optical disc 1 is an optical recording medium capable of recording, reproducing and erasing information (only RW and RAM) by a semiconductor laser. For example, the optical disc 1 includes a CD-R, a CD-RW, a DVD ± R, a DVD-RW, a DVD-RAM, and the like.

The ROM 220 is a nonvolatile memory that stores a recommended write policy or an existing adjusted write policy for an unknown disk. By the designer, the ROM 220 stores a write policy corresponding to various disks and the like. The write policy memory unit 218 temporarily stores the write policy memory parameter calculated by the write policy operation control unit 216.

The write policy operation control unit 216 sets initial conditions of each policy based on the recommended write policy read from the ROM 220 or the existing adjusted write policy. The write policy calculation control unit 216 sends the set data to the recording pulse adjustment unit 226, and records predetermined data on the optical disc 1. Further, on the basis of the recording result recorded under the initial condition, the data discrimination calculating unit 212 calculates the calculated calculation result and determines the peak power Pp and epsilon with the best recording quality.

In addition, in order to determine the pulse width of the target policy parameter according to the present invention based on Pp and ε, the policy parameters of the power meter and the pulse width meter (e.g., top pulse, top cleaning pulse, multi pulse, last pulse, The value of any two parameters among pulse widths such as cooling pulses and powers such as peak power, erase power, bias power, comparison of the erase power and the peak power (?), Etc. The conditions for requesting the recording quality can be set. Alternatively, the pulse width of the target policy parameter can be determined by setting a condition for obtaining the minimum value of the DOW (less than 50 times) of any one parameter or the lower limit peak power of the DOW (1). Alternatively, the pulse width of the target policy parameter can be determined by correcting the policy parameter corresponding to the minimum value of the lower limit peak power and sending it to the recording pulse adjustment unit 226.

Subsequently, the result of the recording is compared and judged based on the calculation result calculated by the data discrimination calculating unit 212, and the optimum values of the policy parameters of the power meter and the pulse width meter indicating the optimal recording quality are determined. That is, the optimum value of the two parameters is determined with the position obtained by the minimum position, the maximum position, the center value of the slice level, or the center value of the recording quality on the two-dimensional matrix, or the DOW (1) of any one parameter. The value corresponding to the minimum value of the lower limit peak power in () is determined as the optimal value of the policy parameter, or a predetermined correction amount is added or subtracted to the value of the policy parameter corresponding to the minimum value to determine the optimal value. This operation is repeated for other policy parameters or combinations thereof to determine the optimum value for all or part of the policy parameters. At this time, the data of the optimum pulse width of the determined target policy parameter is stored in the final policy memory unit 218, and is read as appropriate during the user's operation.

The recording pulse adjusting unit 226 inputs pulse setting parameter data from the final policy calculation control unit 216, generates a recording pulse string, and outputs the generated pulse string to the laser driver 228. The laser driver 228 generates a laser diode driving pulse signal in response to the input recording pulses, outputs the pulse signal to the semiconductor laser in the optical pickup 200, and the semiconductor laser writes predetermined data to the optical disc 1.

The head amplifier 202 calculates the reflected light amount by the reflected light detected by the optical pickup 200 from the optical disk 1, generates an RF signal indicating the total amount of the light, and the semiconductor laser of the optical pickup 200. A focus error signal, which is a signal for detecting a focus error, and a tracking error signal, which is a signal for detecting a track error, are generated.

The binarization circuit 204 is a reproduction signal generation circuit which forms a detection signal from the head amplifier 202 and generates binary digital signals according to marks and spaces. In other words, the binarization circuit 204 binarizes various signals of analog 3T, 4T, 5T, ... outputted from the head amplifier 202 and always adjusts a threshold for correcting the pulse waveform.

The clock error measuring unit 208 measures the determination parameter for determining the pulse width of the target policy parameter. That is, the clock error measuring unit 208 acquires data from the binarization circuit 204 and measures errors of edges and clock edges of various signals. As for the pulse edge of a recording pulse train, a predetermined amount (DELTA) T increases and decreases according to conditions, and the change amount dT of the mark edge measured at this time is measured. At this time, the recording quality for each error may correspond.

The RAM 210 is a memory that temporarily stores data measured by the clock error measuring unit 208. That is, in the RAM 210, the mark edge measured when the clock error of the various signals set by the write policy operation control unit 216, the number of samples for each signal type, and the prescribed amount ΔT of the reproduction signal recorded by the other write policy are moved. Change amount dT and the like are stored.

The data discrimination calculating unit 212 calculates an error with respect to the amount of change of various signals set by the write policy calculation control unit 216 based on the measurement data stored in the RAM 210. The calculated data is output to the write policy operation control unit 216 so that the recording quality of each error can correspond.

Next, policy parameters targeted by the present invention will be described. 2 is a pulse waveform diagram showing a multi-pulse waveform of a target policy parameter. In FIG. 2, the target policy parameters are the pulse width Top of the top pulse of the recording multi-pulse, the pulse width Tpc of the top cleaning pulse, the pulse width Tmp of the multi-pulse, and the pulse width of the last pulse ( Tlw) and five pulse widths of the cooling pulse pulse width Tcw will be described. In addition, parameters defining powers such as peak power Pp, erase power Pe, bias power Pb, and epsilon are added to the policy parameters as targets. Policy parameters may be combined. Pp for melting the recording area of the disc and Pe for crystallizing the recording area have a relationship of ε = Pe / Pp. Pb forming a recording mark by quenching assumes a case of zero.

Next, an embodiment of the first method of the present invention will be described. FIG. 3 is a recording quality table showing the lower limit peak power at which the recording quality when the pulse widths of the cooling pulse and the last pulse are changed two-dimensionally in the DOW 1 becomes a desired limit value. In FIG. 3, it is assumed that the minimum point of the lower limit peak power exists in Tcw of 6-9 and Tlw of 19-22 shown in ellipse. Calculating this minimum point by two-dimensional two-order approximation yields Tlw = 20.33, Tcw = 7.72, and a correlation coefficient of 0.91. The optimal pulse width can be determined by using the pulse width values at this time as the pulse widths of the cooling pulse and the last pulse. This operation can be repeated for a combination of other policy parameters to determine the optimum pulse width of all target policy parameters. In addition, since the recording characteristic of the DOW 1000 is not required, the policy can be adjusted in a short time.

FIG. 11 is a recording quality table showing the block error rate when the epsilon and the peak power are changed two-dimensionally in the DOW 1. In the case of this table, the values determined as a result of the two-dimensional quadratic approximation are Pp = 28.9 mW and ε = 0.27. In order to make this extensive matrix measurement and to calculate the minimum position of the PIE, more accurate recording power can be determined.

Next, the Example of the 2nd method of this invention is described. Fig. 4 is a recording quality table showing the DOW (1) block error rate (PIE) when the width and peak power of the last pulse are changed two-dimensionally, and the lower limit peak power for each last pulse width at this time. Is also shown. In FIG. 4, the change in Tlw of the lower limit peak power Pp is described in detail in FIG. 8, but since it is similar to the power margin, it is possible to determine Tlw in the relationship between Tlw and Pp. This Pp? Represents the recording power at which the recording quality of direct overwrite recording becomes a desired threshold value, and the PIE may be replaced by jitter.

For this reason, the method of calculating | requiring the graph of Pp (s) with respect to Tlw is demonstrated. FIG. 5 is a Pp-PIE characteristic diagram showing the relationship between the peak power using the pulse width of the last pulse as a parameter and the block error rate of the DOW (1) proxy in the DOW (1). In Fig. 5, attention is paid to the intersection of the lower limit slice level 1280 of the PIE set in advance by each curve having Tlw as a parameter and the standard value.

Fig. 6 is a Tlw-Pp? Characteristic diagram showing the relationship between the width of the last pulse and the lower limit peak power. In Fig. 6, the solid line is obtained by plotting Pp? Determined at the intersection with the lower slice level 1280 as the angular curve of Fig. 5 and Tlw of the curve. The dashed line is a quadratic function approximation of the plotted curve, with a correlation coefficient of 0.9903. In addition, the value of the pulse width which shows the minimum value by this quadratic function approximation is 0.645. Thereby, the secondary curve of FIG. 6 is obtained by numerical calculation based on the data collected in FIG. 5, and it is possible to automatically obtain Tlw. For this reason, by repeating this operation for each policy parameter, it is possible to determine all the policy parameters in a short time and precisely with the DOW 1 alone. In addition, the DOW 1 may be a DOW (50 or less).

Next, an embodiment of the third method of the present invention will be described, and the relationship between the upper limit peak power Pp u and the lower limit peak power Pp? And the power margin of the peak power Pp will be described. Fig. 7 is a power margin diagram showing the relationship between the peak power at the time of rewriting and the block error rate. The upper limit slice level 1700 and the lower limit slice level 1280 of the PIE are set in advance as standard values.

In Fig. 7, from Pp and PIE in DOW (0) to DOW1000, Pp in DOW 1000 first intersects the upper slice level 1700 of PIE, and Pp u is 32.1 mW. It is. In addition, Pp in the DOW 1 intersects with the lower limit slice level 1280 of the PIE for the first time, and Pp is 22.4 mW. From this, the power margin is PpU-Pp? = 32.1-22.4 = 9.7 mW. The policy adjustment of the rewritable disc requires a lot of time to perform the DOW 1000 recording required for this how to adjust this power margin widely. 7, the recording characteristics of the DOW 1 and the DOW 1000 are in a trade-off relationship with each other.

A third embodiment of the present invention will be described. Fig. 8 is a correlation diagram showing the relationship between the lower limit peak power when the last pulse is changed in the DOW 1 and the upper limit peak power when the last pulse is changed in the DOW 1000 and the power margin. to be. In FIG. 8, Pp u and power margin are approximated to a quadratic curve having a maximum with respect to Tlw. In contrast, Pp? Is approximated to a quadratic curve having a minimum value for Tlw, and a peak is remarkable compared to Pp P. In addition, the Tlw with the minimum Pp and the Tlw with the maximum power margin almost coincide. It is presumed that the power margin is maximized by obtaining Tlw whose Pp is minimum.

Fig. 9 is an extreme table obtained by quadratic approximation of Tlw, which is the minimum of the lower limit peak power of each disk, and Tlw, which is the maximum power margin. The difference (Δ-b / (2a)) between Tlw, which is the maximum power margin and Tlw, which is the lowest peak power minimum, is unbalanced, but is -0.1 as an average value. By subtracting the correction value from the calculated Tlw that is the calculated Pp minimum, the absolute value of this value can be obtained as a correction value Tlw. At this time, the corrected Tlw becomes Tlw which enlarges the power margin. For this reason, a more accurate optimum Tlw can be determined by obtaining the correction value of Tlw and subtracting this correction value from Tlw which becomes the minimum of calculated Pp ?.

1 is a flowchart illustrating a method of determining a recording policy of an optical disc drive according to the present invention. In FIG. 1, initial setting of each policy is performed based on the disc recommendation policy or the existing adjustment completion policy (step 110). Based on this initial setting, the recording quality is determined by changing the epsilon and Pp in the two-dimensional matrix, and Pp and epsilon which are the best recording quality are determined (step 120). Based on this Pp and [epsilon], the edge position optimization (EPO) operation of determining the pulse width of the target policy parameter is started (step 130). If it is caused by any two combinations of the target policy parameters, it changes to a two-dimensional matrix. The recording quality is determined to determine the optimum pulse widths of the two target policy parameters whose recording quality on the two-dimensional matrix is the best (steps 140, 170, 180). The same process is repeated until all target policy parameters have been determined (step 190).

If the result is a combination of any one of the target policy parameters and the lower limit peak power, the pulse width of any one of the target policy parameters is changed to determine the minimum value of the lower limit peak power at the time of DOW (1), The optimum pulse width of the one target policy parameter corresponding to the minimum value of the peak power is determined (steps 150, 170, 180). The same process is repeated until all target policy parameters have been determined (step 190).

If the correction value is combined as a result of the combination of any one of the target policy parameters and the lower limit peak power, the lower limit peak power at the time of DOW (1) is changed by changing the pulse width of any one of the target policy parameters. The minimum value is obtained, and the optimum pulse width is determined by subtracting or adding a predetermined correction value from the pulse width of the one target policy parameter corresponding to the minimum value of the lower limit peak power (steps 160, 170, 180). The same process is repeated until all target policy parameters have been determined (step 190).

As described above, the present invention provides an optical disc drive recording policy determination method and an optical disc drive capable of determining an optimal recording policy in a short time and accurately with respect to an optical disc in which the recording policy is unknown in the optical disc drive. It becomes possible.

1 is a flowchart showing a recording policy determination method according to the present invention;

2 is a pulse waveform diagram showing a multi-pulse waveform of a target policy parameter;

3 is a recording quality table when the widths of cooling pulses and last pulses are changed two-dimensionally in the DOW 1;

4 is a recording quality table when the last pulse width and peak power are changed two-dimensionally in the DOW 1;

5 is a Pp-PIE diagram in which the width of the last pulse in the DOW 1 is parameterized;

Fig. 6 is a Tlw-Ppｌ diagram showing the relationship between the width of the last pulse and the lower limit peak power;

7 is a power margin diagram based on the peak power and the block error rate using the number of rewrites as a parameter;

8 is a correlation diagram of upper and lower limit peak power and power margin for a last pulse;

9 is an extreme table obtained by quadratic approximation of Tlw, which is the minimum of the lower limit peak power of each disk, and Tlw, which is the maximum of the power margin;

10 is a basic functional block diagram of an optical disk drive for executing the method according to the present invention; And

11 is a recording quality table when the epsilon and peak power in the DOW 1 are changed two-dimensionally.

Claims (6)

In a recording policy determination method of an optical disc drive, in which marks and spaces are formed on an optical disc by laser light to display recording information, and information is recorded or reproduced: Evaluating the recording quality while changing on the two-dimensional matrix by combining at least two of the parameters corresponding to the power meter and the pulse width meter and defining the recording multi-pulse; And And determining, as policy parameters, parameters of the power meter and pulse width meter indicating a specific recording quality, based on the evaluation result of the recording quality. The method of claim 1, In the evaluating step, the recording policy determination method of the optical disc drive for obtaining the recording power such that the recording quality of the direct overwrite for redundant input recording is changed by changing the value of any one of the at least two parameters. . The method of claim 2, And in the determining step, determines any parameter corresponding to the target value as the target value as a policy parameter. The method of claim 3, wherein And subtracting or adding a predetermined correction amount from the one parameter to determine a final policy parameter. The method of claim 2, And recording the duplicated input once. In an optical disc drive in which a mark and a space indicating recording information are formed on an optical disc by laser light, and the information is recorded or reproduced: An arithmetic process that corresponds to a power meter and a pulse width meter and evaluates the recording quality while changing on a two-dimensional matrix by combining at least two of the parameters defining the recording multi-pulse, and based on the evaluation result of the recording quality. A write policy operation control unit that determines parameters indicating a specific recording quality as policy parameters of the power system and the pulse width system; And And a recording pulse adjusting unit for generating and outputting a recording pulse string with reference to the determined policy parameter.

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