JP3876676B2 - Optical disk device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to power optimization of an optical disk apparatus, and more particularly to an apparatus for recording data on a recordable optical disk.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, recordable optical disk devices are known and are commercialized as DVD-R and the like.
[0003]
In a recordable optical disk device such as a DVD-R, a recording power optimization process called OPC (Optimum Power Control) is performed prior to actual data recording. The OPC records the test data in a test area provided at a predetermined position on the optical disk by changing the recording power in a plurality of sectors in a plurality of sectors, for example, 16 steps in 16 sectors, and each test data for each sector is recorded. And evaluate the signal quality. The β value is usually used as the quality of the reproduction signal. The β value is a parameter calculated from β = (A + B) / (A−B) from the peak voltage (A) and the bottom voltage (B) of the envelope of the AC coupled reproduction RF signal, and this value is It is optimal in the case of a predetermined range (for example, 0.04 to 0.05). The AC-coupled reproduction RF signal is a signal obtained by removing the DC component of the reproduction RF signal and making only the AC component. Then, the recording power at which a desired β value (reference β value) is obtained is selected as the optimum recording power, and thereafter data is recorded with this optimum recording power.
[0004]
In JP-A-7-85494, a β value lower than a desired β value and a β value higher than a desired β value are obtained, and a linear approximation is performed from the power stage when these two β values are obtained. Describes that the virtual power stage of the recording power at which a desired β value is obtained is obtained, and the recording power of the power stage closest to the virtual power stage is set as the optimum recording power.
[0005]
[Problems to be solved by the invention]
However, there are various types of optical discs used for recording, and there are variations in recording characteristics and quality from one optical disc to another, so there can be various reference β values. Although it is possible to select an optimum recording power using a default β value (for example, β = 0.04) prepared in advance, if the reference β value differs for each optical disc, the optimum recording quality is not necessarily obtained. It is not necessarily obtained. For this reason, in some cases, the recording power may be set based on a β value higher than the original optimum β value. As a result, the RF signal may be distorted due to thermal waveform distortion and may not be reproduced.
[0006]
Although a table may be provided in advance in a microcomputer or the like built in the optical disk device, and the reference β value may be calculated and stored for each disk medium manufacturer, the processing at the time of manufacturing the device becomes complicated. In addition, it is not possible to insert an optical disc that does not store the reference β value.
[0007]
Also, the optical disk device (drive) of the same manufacturer calculates the β value of the same optical disk due to differences in optical characteristics such as LD (laser diode) wavelength variations of optical pickups and accuracy errors of the components that make up the β value calculation circuit. Even so, the value will be different for each drive. As a result, even if there is a combination of a drive and an optical disk that can obtain the optimum recording power with the reference β value (for example, β = 0.04), the other drive selects the optimum recording power using the reference β value. However, the optimum recording quality is not always obtained.
[0008]
Although it is possible to calculate the β value calculation error for each optical disk device in advance at the time of manufacturing the device and correct the reference β value for each disk medium manufacturer, the processing becomes more complicated. Further, when the change with time or the characteristic of the pickup occurs, the correction accuracy is lowered.
[0009]
The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an apparatus capable of recording data with high quality by setting an optimum recording power for each optical disk and each optical disk apparatus. It is in.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in an optical disc apparatus for recording data on an optical disc having a read-only area in which an embossed portion is formed in advance, the embossed portion of the optical disc is played and the β value of the playback signal is set to means for calculating as a 1β value, and means for recording the pits while changing the recording power in a predetermined test area of the optical disc, the β value of the reproduction signal to reproduce the pits recorded in the respective recording power first Means for calculating as a 2β value, means for storing the calculated second β value in association with recording power, means for calculating a target β value by multiplying the first β value by a predetermined coefficient, and the recording Means for selecting a recording power corresponding to the target β value based on the correspondence between the power and the second β value, and means for setting a strategy suitable for the optical disc. Wherein the recording data on the optical disc at the recording power and the set strategies are.
[0011]
According to the present invention, in an optical disc apparatus for recording data on an optical disc having a read-only area in which an embossed portion is formed in advance, means for reproducing the embossed portion of the optical disc and calculating the β value of the reproduced signal as the first β value Means for recording pits by changing recording power in a predetermined test area of the optical disc; means for reproducing pits recorded at each recording power and calculating a β value of the reproduced signal as a second β value; means for storing the calculated first 2β value in association with the recording power, and means for calculating a target β value by adding or subtracting a predetermined value for the first 1β value, the recording power and the 2β value And a means for selecting a recording power corresponding to the target β value, and a means for setting a strategy suitable for the optical disc. Wherein the recording data on the optical disk in power and set strategy.
[0013]
The target β value is preferably calculated according to land recording and groove recording.
[0014]
Thus, in the optical disc apparatus of the present invention, when recording data on an optical disc having a read-only area in which an embossed portion is formed in advance, the recording power is optimized based on the β value obtained by reproducing the embossed portion of the optical disc. Turn into. The β value obtained by reproducing the embossed portion is different for each optical disc or each optical disc apparatus. Further, since the embossed portion is formed in advance at the time of manufacturing the optical disc, the β value is the best condition value. By setting the target β value based on this β value, it is possible to set an appropriate target β value in the combination of the optical disc and the optical disc apparatus, and to optimize the power. Also, by setting a strategy suitable for the optical disc, pits having a desired size and shape can be formed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
【Example】
FIG. 1 is a block diagram showing a main configuration of the optical disc apparatus according to the present embodiment. The optical disk device is composed of an optical pickup unit 12, a control unit 14, and a signal processing unit 16.
[0017]
The optical pickup unit 12 performs recording and reproduction by irradiating the optical disk 100 rotated by the spindle motor 10 with laser light. A drive signal for recording is supplied from the control unit 14, and data is recorded by forming pits having a length of 3T to 14T (where T is a reference period of the length in the track direction) on the optical disc 100. Further, the reproduction RF signal obtained from the reflected light by irradiating the laser beam with the reproduction power is output to the signal processing unit 16.
[0018]
The signal processing unit 16 demodulates the input RF signal and outputs it as reproduction data. Although not shown, demodulation is performed by removing noise with a filter (for example, LPF), shaping the waveform with an equalizer, generating a synchronous clock with a PLL circuit, and extracting reproduced data. Further, the signal processing unit 16 extracts a tracking error signal and a focus error signal from the optical pickup unit 12 and outputs a servo signal to the optical pickup unit 12. Further, the signal processing unit 16 supplies an RF signal to the control unit 14.
[0019]
The control unit 14 generates a drive signal for driving an LD (laser diode) in the optical pickup unit 12 based on the recording signal supplied from the host device. Further, the control unit 14 performs recording power optimization (OPC) prior to actual data recording. As described above, the OPC records the test data in a test area provided at a predetermined position on the optical disk by changing the recording power for every 16 sectors in, for example, 16 sectors, and records each test data for each sector. Reproduction is performed by detecting the β value. After calculating the β value for each recording power, the control unit 14 sequentially stores the β value as a function of recording power (β value vs. power function), and selects the recording power at which the target β value is obtained as the optimum recording power. To do. Specifically, a β value obtained by reproducing a previously formed embossed portion of the optical disc 100 is set as a target β value, and a recording power that can obtain the target β value is selected. Conventionally, the control unit 14 uses a default value (for example, 0.04) as a reference β value (target β value). Set dynamically according to the setting.
[0020]
When the optimum recording power is selected and data is recorded, the control unit 14 can further control the recording power by ROPC (Running Optimum Power Control). Here, ROPC compares the reflected light intensity of the pits during OPC and data recording, and corrects the optimum recording power as needed to maintain the reflected light intensity constant.
[0021]
FIG. 2 is a block diagram illustrating a configuration of the control unit 14. Specifically, the control unit 14 is configured by a DSP or the like, and includes a recording signal generation unit 14a, an LD (laser diode) drive signal generation unit 14b, a β value calculation unit 14c, a storage unit 14d, and a calculation unit 14e as functional blocks. .
[0022]
The recording signal generation unit 14a modulates the recording signal by 8/16 and outputs the recording signal at a transfer rate corresponding to the recording speed of the optical disc 100. The recording signal may be output after being corrected according to the optimal strategy (recording pulse emission waveform rule) set for each type of optical disc 100 and each manufacturer in order to form a pit having a desired size and shape. Is preferred.
[0023]
During OPC, 16 stages of recording power pulses stored in advance in a table format in the storage unit 14d are output, and the LD of the optical pickup unit 12 is driven via the LD drive signal generation unit 14b.
[0024]
The β value calculation unit 14c calculates the β value for each recording power by β = (A + B) / (A−B) from the AC-coupled RF signal envelope of the test data respectively recorded at the recording power of 16 levels in the OPC. To calculate. However, A is a peak voltage and B is a bottom voltage. The calculated β value is sequentially supplied to the storage unit 14d. There are two types of β values calculated by the β value calculating unit 14c. The first is a β value of a reproduction RF signal obtained by reproducing an embossed portion formed in advance of the optical disc 100, and the second is the value of the optical disc 100. This is the β value of a reproduction RF signal obtained by reproducing pits recorded with various recording powers in the test area. The β value of the embossed part is also supplied to the storage part 14d.
[0025]
The storage unit 14d reproduces the pit recorded by changing the recording power in a predetermined test area of the optical disc 100 in addition to the β value obtained by reproducing the embossed portion of the optical disc 100 calculated by the β value calculating unit 14c. The β value obtained in this way is stored. The β value obtained by reproducing the pit recorded in the test area is stored in association with the recording power. For example, the two-dimensional data is (power Pw1, β1), (power Pw2, β2). The relationship between the recording power and the β value can be approximated by a function (β vs. power function) and stored as a parameter of this function.
[0026]
The calculation unit 14e obtains the recording power corresponding to the target β value, which is the β value of the embossed part stored in the storage unit 14d, from the relationship between the recording power stored in the storage unit 14d and the β value. Then, the recording power at which this target β value is obtained is selected as the optimum recording power and supplied to the recording signal generation unit 14a.
[0027]
In the present embodiment, the embossed portion means information pits (prerecords) formed in advance in the control data zone 102, which is a reproduction-only area in the inner peripheral portion of the optical disc 100, as shown in FIG. When calculating the β value of the embossed portion, the information pits in the control data zone 102 may be reproduced.
[0028]
Hereinafter, the operation of the control unit 14 in the present embodiment will be described in detail.
[0029]
FIG. 4 is a process flowchart of the control unit 14 in OPC. First, when receiving a recording command from the host device, the control unit 14 drives the optical pickup unit 12 to reproduce the information pits of the embossed portion formed in advance with a predetermined reproduction power (S101). Then, the β value is detected from the AC-coupled reproduction RF signal envelope obtained at this time, and βe, which is the β value, is stored in the storage unit 14d (S102). This βe is different for each optical disc 100 and each optical disc device, and is generally the most reliable optimum value than the β value obtained by reproducing data after recording data on the optical disc 100 by the optical disc device. This is because the data pits are recorded under the best conditions because they are information pits in the embossed portion formed in advance when the optical disc is manufactured.
[0030]
Next, the control unit 14 drives the optical pickup unit 12 to form pits by variously changing the recording power in a test area formed in a predetermined area of the optical disc 100, and reproducing the pits to obtain a β value. Is calculated and stored in the storage unit 14d (S103). Specifically, test data is recorded in a predetermined test area (PCA) of the optical disc 100 with recording power that gradually increases in 16 steps. The power at this time is Pw1, Pw2,..., Pw16. Then, the test data recorded with each recording power is sequentially reproduced, and its β value is calculated. The β values for each recording power are β1, β2,..., Β16, respectively.
[0031]
FIG. 5 is a diagram showing β1 to β16 obtained by recording pits by sequentially changing the recording power Pw1 to Pw16 in the test area and reproducing each pit with a predetermined reproduction power. The horizontal axis is the recording power (mW), and the vertical axis is the β value. The β value generally increases as the recording power increases and changes almost linearly. However, when the recording power exceeds a certain value, the inclination of the β value with respect to the recording power change, that is, the β value change rate becomes small. This portion can be said to be a recording power range in which the RF signal causes thermal waveform distortion.
[0032]
After storing the relationship between the recording power and the β value, the control unit 14 sets βe obtained by reproducing the information pit in the embossed portion as a target β value (S104). Based on the relationship between the recording power stored in the storage unit 14d and the β value, the control unit 14 selects a recording power (optimal recording power) that provides the target β value and sets the power of the laser diode of the optical pickup unit 12 Control and record data with the optimum recording power (S105). If the correspondence between the recording power and the β value is stored discretely (Pwi, βi) (i = 1, 2,...) In the storage unit 14d, the recording corresponding to the target β value is performed. The power may be calculated by interpolation processing.
[0033]
FIG. 6 is a diagram showing the relationship between βe (target β value) and the optimum recording power Pwo described above. Βe, which is the β value of the embossed portion (information pit), is a reference β value determined by the combination of the optical disc 100 and the optical disc apparatus, and indicates the reproduction signal quality of the optical disc 100 and the optical disc apparatus. This reproduction signal quality βe is set to a target β value at the time of data recording. The recording power Pwo at which this target β value is obtained is set as the optimum recording power. It should be noted that the recording power Pwo is not a recording power determined based on a fixed β value, but dynamically changes according to a β value βe at the embossed portion.
[0034]
As described above, in this embodiment, since the recording power is optimized with the β value obtained by reproducing the pre-embossed portion of the optical disc 100 as the target β value, when recording data on another optical disc 100 and A case where data is recorded by another optical disk apparatus can also be handled.
[0035]
FIG. 7 is a diagram showing characteristics when data is recorded on the optical disc A and the optical disc B by the optical disc apparatus according to the present invention. In the figure, the solid line is the characteristic of the optical disc A, and the alternate long and short dash line is the characteristic of the optical disc B. In the optical discs A and B, the β values obtained by reproducing the embossed portions are different from βea and βeb, respectively, and the target β values are also different due to this. As a result, the optimum recording power is also Pwoa and Pwob, respectively. If the target β value (reference β value) is a fixed value, the optical disc A sets the recording power based on a β value lower than the original optimum β value βea. For this reason, the recording power becomes small and sufficient recording quality cannot be obtained, and the reproduction signal quality may be deteriorated. In the optical disc B, the recording power is set based on a β value higher than the original optimum β value βeb. Therefore, it can be seen from the figure that the recording power becomes large and excessive, and the RF signal may be distorted due to thermal waveform distortion, making it impossible to reproduce.
[0036]
FIG. 8 is a diagram showing characteristics when data is recorded on the same optical disc by the optical disc apparatus A and the optical disc apparatus B according to the present invention. In the figure, the solid line is the characteristic of the optical disc apparatus A, and the alternate long and short dash line is the characteristic of the optical disc apparatus B. If the optical disk device is different, an error occurs in the β value measurement due to variations in parts even in the same configuration and the same manufacturing process. In the optical disc apparatuses A and B, the β values obtained by reproducing the embossed part of the same optical disc are different from βea and βeb, respectively, and the target β values are also different due to this. As a result, the optimum recording power becomes Pwoa and Pwob, respectively. If the target β value (reference β value) is a fixed value regardless of the optical disk device, the optical disk device A sets the recording power with a β value lower than the original optimum β value βea as a reference. As a result, the recording power is reduced. Further, in the optical disk apparatus B, the recording power is increased because the recording power is set based on a β value higher than the original optimum β value βeb. In other words, it can be seen from the figure that even though recording is performed on the same optical disk, the recording power varies greatly depending on the optical disk device, and the optimum recording quality may not be obtained. However, since the optical disk apparatus according to the present invention can absorb variations in the apparatus, recording is performed with an optimum recording power as viewed from the optical disk side.
[0037]
The target β value βd may be calculated using the β value βe obtained by reproducing the embossed portion. Specifically, using the coefficient Dw,
[Expression 1]
βd = βe · Dw (1)
To calculate the target β value βd. Here, Dw is, for example, a value satisfying −1.5 <Dw <1.5 (however, 0 is not included). The meaning of the formula (1) is as follows. If there is an error in the β value measurement of the optical disk device (drive) or if there is a drive error in the LD in the optical pickup unit, βe measured by the drive is varied by a predetermined amount or a predetermined ratio to calculate a target β value βd, If the target β value (reference β value) at the time of actual data recording is used, the recording power with the error offset can be set with higher accuracy.
[0038]
The coefficient Dw can be a fixed value (for example, D = 1.2) for each optical disk device (drive) or each disk medium manufacturer, and may be stored in advance in the storage unit of the drive.
[0039]
Further, when data is recorded on both the land portion and the groove portion of the optical disc 100, the recording characteristics are different between the land portion and the groove portion. Therefore, the above processing is performed on the land portion and the groove portion, respectively. It is also preferable to set the optimum recording power and the optimum recording power at the time of groove recording. In this case, the other target β value may be calculated by multiplying the target β value based on βe, which is one of the reference β values, by a predetermined coefficient. Also, different values can be used for the land portion and the groove portion for calculating the target β value βd based on the reference β value βe.
[0040]
As mentioned above, although embodiment of this invention was described, this invention is not limited to this, A various change is possible. For example, in this embodiment, the case where the target β value is calculated based on the expression (1) has been described. For example, M is set to a predetermined value (−5.0 <M <5.0).
[Expression 2]
βd = βe + M (3)
It is also possible to calculate the target β value, and the target β value can be calculated by an arbitrary arithmetic expression using βe which is the reference β value, βd = f (βe).
[0041]
【The invention's effect】
As described above, according to the present invention, the optimum recording power can be set for each optical disc and each optical disc apparatus. Also, by setting a strategy suitable for the optical disc, pits having a desired size and shape can be formed.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a main part of an optical disc apparatus according to an embodiment.
2 is a configuration block diagram of a control unit in FIG. 1;
FIG. 3 is a configuration diagram of an optical disc.
FIG. 4 is a process flowchart of a control unit according to the embodiment.
FIG. 5 is a graph showing the relationship between recording power and β value.
FIG. 6 is an explanatory diagram showing a relationship between a target β value and optimum power.
FIG. 7 is an explanatory diagram showing characteristics of the optical disc A and the optical disc B;
FIG. 8 is an explanatory diagram showing characteristics of the optical disc apparatus A and the optical disc apparatus B;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Spindle motor 12 Optical pick-up part 14 Control part 16 Signal processing part 100 Optical disk

Claims (3)

In an optical disc apparatus for recording data on an optical disc having a read-only area in which an embossed portion is formed in advance,
Means for calculating with the β value of the reproduction signal and the 1β value plays the embossed portion of the optical disc,
Means for recording pits by changing recording power in a predetermined test area of the optical disc;
Means for reproducing a pit recorded at each recording power and calculating a β value of the reproduced signal as a second β value;
Means for storing the calculated second β value in association with the recording power;
Means for multiplying the first β value by a predetermined coefficient to calculate a target β value;
Means for selecting a recording power corresponding to the target β value based on the correspondence between the recording power and the second β value;
Means for setting a strategy suitable for the optical disc;
And recording data on the optical disc with a selected recording power and a set strategy. In an optical disc apparatus for recording data on an optical disc having a read-only area in which an embossed portion is formed in advance,
Means for reproducing the embossed portion of the optical disc and calculating the β value of the reproduced signal as the first β value;
Means for recording pits by changing recording power in a predetermined test area of the optical disc;
Means for reproducing a pit recorded at each recording power and calculating a β value of the reproduced signal as a second β value;
Means for storing the calculated second β value in association with the recording power;
Means for calculating a target β value by adding or subtracting a predetermined value for the first 1β value,
Means for selecting a recording power corresponding to the target β value based on the correspondence between the recording power and the second β value;
Means for setting a strategy suitable for the optical disc;
And recording data on the optical disc with a selected recording power and a set strategy. The apparatus according to claim 1 or 2,
The target β value is calculated according to each of land recording and groove recording .

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