JP2009015883A - Optical disc apparatus and control method thereof - Google Patents

Abstract

The present invention provides an optical disc apparatus capable of calculating and setting an optimum recording power by changing the recording power over a wide range in OPC using the β value of the optical disc, and a control method therefor.
When recording data on a recordable optical disk by changing the recording power in the OPC of the optical disk apparatus, the bias power of the recording power is multiplied by a predetermined first coefficient to the standard value of the bias power of the recordable optical disk. The recorded power is recorded, and the recorded data is reproduced, and the recording power obtained by multiplying the provisional recording power calculated based on the measured β value by the predetermined second coefficient is set as the optimum recording power.
[Selection] Figure 1

Description

  The present invention relates to an optical disc apparatus that handles CD, DVD, HD DVD, and the like.

  A plurality of types of recording density optical disks called CD (Compact Disc) standards and DVD (Digital Versatile Disk) standards are already widely used. In recent years, by recording information using laser light of a blue-violet wavelength, In addition, an ultra-high density optical disk HD DVD (High Density Digital Versatile Disk) with a further increased recording density has been put on the market.

  When data is recorded on the recordable optical disk among the above optical disks, it is necessary to record with an appropriate recording power. For this reason, trial writing is performed on the PCA (Power calibration area) of the optical disc, and this data is reproduced to determine the optimum recording power. This series of processing is called OPC (Optimum Power Control). Yes. Since OPC varies depending on the operating environment of the optical disk device, the state of the mounted optical disk, the recording speed, etc., it is executed before the start of recording in order to determine the optimum recording power under conditions close to the actual recording operating environment. .

  As one of the specific methods of OPC, random pattern (random data) or regular pattern data is recorded and the recorded data is reproduced while changing the recording power to PCA in several steps or more than a dozen steps. Then, there is a method of evaluating the β value or error rate, or various waveform data, and determining an optimum recording power by a calculation method based on each index.

  The β value is a value indicating the degree of upper and lower imbalance of the RF signal of the reproduction signal, and is used when evaluating the reproduction signal quality. The β value is calculated by β = (A−B) / (A + B) where A is the peak voltage of the envelope when the RF signal is AC-coupled and B is the bottom voltage of the envelope of the RF signal. Usually, when β≈0, the unbalance is small and the reproduction signal quality is good, and it is used as one index of OPC.

However, there are various types of optical discs used for recording, and there is a problem that an optimal β value is not always obtained for an optical disc mounted on an optical disc apparatus. In order to solve this problem, a method for determining the β value by determining whether or not the default β value is included in a range in which the change rate of the β value for each recording power is equal to or greater than a predetermined threshold is considered. . (For example, refer to Patent Document 1.)
JP 3722017 A

  In an HD DVD-R type optical disc that records information using a blue-violet laser beam, there are recording marks from 2T (T is the minimum bit interval) to 14T, but the 2T signal is on the information recording surface. Smaller than spot size. Bias power is required to generate the 2T mark, but in the conventional OPC recording power swing method and recording pattern applied to DVD-R type optical discs, the space is increased depending on the bias power at high power. There is a problem that the signal portion is also recorded.

  Therefore, in the high power region, the line formation of the recording power and β value collapses rapidly, and a false β value appears that is detected as the optimal β value even though it is not the optimal β value, Incorrect recording power may be set from the false β value.

  FIG. 7 is a diagram showing the relationship between the recording power and the β value in the conventional DVD-R OPC. When the recording power is low, the β value is large. As the recording power increases, the β value decreases, the β value becomes zero, and when the recording power increases further, the β value further decreases. As the power increases, the rate of change decreases. In a relatively small power range with β value ≈ 0, the relationship between the recording power and the β value is a linear relationship. The recording power at the optimum β value is the optimum recording power. For example, the recording power is set to 20 mW for DVD-R 4 × recording and 40 mW for 8 × recording.

  FIG. 8 is a schematic diagram of a recording data signal and a laser emission waveform when recording on a conventional DVD-R. In this case, the bias power Pb is 0.5 mW to 1 mW (milli-Watt), and the recording power is 20 mW for 4 × recording and 40 mW for 8 × recording as described above.

  FIG. 9 is a diagram showing the relationship between the recording power and the β value in the conventional HD DVD-R OPC. As in the DVD-R, in a relatively low power range, the relationship between the recording power and the β value is a linear relationship. However, as the recording power increases, the β value starts to increase, and the β value becomes approximately zero. Value exists. In this state, the portion of the space signal with a small bit interval such as 2T or 3T is not in a state where it has been firmly recorded until the mark recording by the bias power, but becomes a pseudo recording state in which it is not in an unrecorded state. Rises, and a false optimum β value in which β value≈0 appears. The recording power by the false optimum β value at the position where the recording power is large is not actually the optimum recording power. Since such a phenomenon occurs, there is a problem that the recording power cannot be shaken until the recording power becomes large.

  FIG. 10 is a schematic diagram of a recording data signal and a laser emission waveform when recording on a conventional HD DVD-R. In this case, the bias power Pb is 5 mW to 7 mW, and the recording power is 12 mW to 15 mW in 1 × speed recording. Conventionally, when the recording power is changed from a small power to a large power, the laser emission waveform is changed in a similar shape. Therefore, the bias power Pb also changes. When Pb exceeds 8 mW, the above-described indication of the pseudo recording state appears.

  The purpose of OPC is to check the recording state and the reproduction state in consideration of the operating environment such as optical disk variation, optical disk device variation, temperature, etc. It is desirable to calculate and set the correct recording power.

  The present application has been made in view of the above circumstances, and an optical disc apparatus capable of calculating and setting an optimum recording power by changing a recording power over a wide range in an OPC using a β value, and a control method thereof. The purpose is to provide.

  In order to achieve the above object, an optical disc apparatus according to the present invention includes a recording means for recording data on a recordable optical disc by changing recording power, and a reproduction for reproducing the data recorded by the recording means and generating an RF signal. Means, β value measuring means for measuring the β value from the RF signal generated by the reproducing means, and recording power calculating means for calculating and setting the recording power based on the β value measured by the β value measuring means And the recording means records at a recording power obtained by multiplying a standard value of the recording power of the recordable optical disc by a predetermined first coefficient, and the recording power calculation means adds the measured β value to the measured β value. The recording power obtained by multiplying the recording power calculated based on the predetermined second coefficient is set as the optimum recording power.

  In order to achieve the above object, the method of controlling an optical disc apparatus according to the present invention includes a step of recording data on a recordable optical disc by changing recording power, and reproducing the data recorded by the recording means to generate an RF signal. A step of measuring the β value from the RF signal generated by the reproducing means, and a step of calculating and setting the recording power based on the β value measured by the β value measuring means. In the recording step, recording is performed with a recording power obtained by multiplying a standard value of the recording power of the recording optical disc by a predetermined first coefficient, and the measured β is calculated in the step of calculating and setting the recording power. A recording power obtained by multiplying the recording power calculated based on the value by a predetermined second coefficient is set as an optimum recording power.

  According to the present invention, in the OPC using the β value of the HD DVD-R optical disk, it is possible to calculate and set the optimum recording power by changing the recording power over a wide range, thereby being stable with respect to the HD DVD-R. Recording operation becomes possible.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an optical disc apparatus 1 to which the present invention is applied. The optical disc 2 is an optical disc capable of recording user data such as HD DVD-R and HD DVD-R DL (Dual layer). A track is formed in a spiral shape on the information recording surface of the optical disc 2, and this optical disc 2 is rotationally driven by a disc motor 3. The disk motor 3 is controlled by a disk motor control circuit 4.

  Information recording and reproduction with respect to the optical disc 2 are performed by the optical pickup 5. The optical pickup 5 is provided with an objective lens 6, and the objective lens 6 can be moved in the focusing direction (the optical axis direction of the lens) by driving the focus direction drive coil 7, and the track direction drive coil 8. Can be moved in the tracking direction (direction orthogonal to the optical axis of the lens).

  The modulation circuit 9 modulates data supplied from the host device 23 via the interface circuit 22 during information recording, and provides the modulated data to the laser control circuit 10. The laser control circuit 10 supplies a write signal to the laser diode 11 in the optical pickup 5 based on the modulated data supplied from the modulation circuit 9 at the time of information recording (mark formation).

  The laser diode 11 generates laser light according to the voltage supplied from the laser control circuit 10. Laser light emitted from the laser diode 11 is irradiated onto the optical disc 2 through the optical component 12 and the objective lens 6. The reflected light from the optical disk 2 is guided to the photodetector 13 in the optical pickup 5 through the objective lens 6 and the optical component 12. An output signal from the photodetector 13 is supplied to the RF amplifier 14.

  The RF amplifier 14 generates a focus error signal and a tracking signal. The focus error signal and the tracking signal are A / D converted and output to the CPU 19 via the bus 18. The CPU 19 generates a focussing control signal and a tracking control signal. These signals are supplied to the focus direction drive coil and the track direction drive coil of the optical pickup 5, and the objective lens 6 is controlled so that the laser light follows the track on the information recording surface of the optical disk 2 and is always in a just focus. The Further, the RF amplifier 14 generates a data reproduction signal of the recording data and outputs it to the data reproduction circuit 16. Further, the RF amplifier 14 supplies an RF signal to the β value measurement circuit 15.

  The β value measurement circuit 15 holds the peak voltage of the envelope when the RF signal is AC-coupled, holds the bottom voltage of the envelope of the RF signal, further A / D converts the hold value, To the CPU.

  The data reproduction circuit 16 reproduces the recording data based on the reproduction clock signal from the PLL circuit 17. The reproduction data reproduced by the data reproduction circuit 16 is error-corrected by an error correction circuit (not shown) using an attached error correction code, and then output to the host device 23 via the interface circuit 22.

  The disk motor control circuit 4, modulation circuit 9, laser control circuit 10, β value measurement circuit 15, data reproduction circuit 16, PLL circuit 17 and the like are controlled by a CPU (Central Processing Unit) 19 via a bus 18.

  The CPU 19 comprehensively controls the optical disc recording / reproducing apparatus 1 in accordance with an operation command supplied from the host device 23 via the interface circuit 22. The CPU 19 uses a RAM (Random Access Memory) 20 as a work area such as a buffer memory at the time of recording and reproduction, and performs predetermined control according to a program stored in a ROM (Read Only Memory) 21. The ROM 21 stores an OPC processing program.

  In the ROM 21, standard values of recording power and bias power of various optical disks are stored. These data are stored in the ROM 21 in the manufacturing process of the optical disc apparatus 1. For the HD DVD-R type optical disc 2, the OPC stores the first coefficient K1 that is multiplied by the standard value of the recording power and the standard value of the bias power, and is calculated based on the measured β value. The second coefficient K2 multiplied by the recording power is stored.

  FIG. 2 is a flowchart showing the operation of OPC using the β value. In S1, the optical disc 2 is loaded in the optical disc apparatus 1, and in the initial operation, the CPU 19 acquires the ID of the optical disc 2. The CPU 19 determines the type of the loaded optical disk. Although the recommended recording power may be included in the information of the ID of the optical disc, the CPU 19 temporarily loads it into the RAM 20.

  In S <b> 2, the CPU 19 acquires a standard value of recording power and a standard value of bias power from the ROM 21 based on the type of optical disc determined in S <b> 1. If the optical disc 2 is an HD DVD-R type or HD DVD-R DL type optical disc, the first coefficient K1 and the second coefficient K2 are also acquired.

  In S <b> 3, the CPU 19 records predetermined recording data in the PCA area of the optical disc 2 while changing the recording power sequentially from several steps to several tens of steps from the small recording power to the large recording power. Here, it is divided into 15 stages as an example. The range from the small power to the large power is preferably in the range of ± 40% to ± 50% of the standard value of the recording power. When the optical disc 2 is of the HD DVD-R type, the recording power and the bias power are recorded with a recording power obtained by multiplying the standard values of the recording power and the bias power by the first coefficient K1 (K1 <1).

  FIG. 3 is a schematic diagram of a recording data signal and a laser emission waveform when recording on an HD DVD-R / DL. The standard value of the recording power Pw is 12 mW to 15 mW at 1 × speed, the standard value of the bias power Pb is 5 mW to 7 mW, and the first coefficient K1 is 0.6 to 0.8. For example, when the optical disc 2 having a standard value of the bias power Pb of 6 mW is multiplied by, for example, a first coefficient K1 of 0.7, the bias power Pb is 4.2 mW. If the standard value of the recording power Pw is 12 mW at 1 × speed, the recording power Pw is 8.4 mW. The recording power Pw used as a reference in OPC is 8.4 mW and the bias power Pb is 4.2 mW. For example, when the recording power is changed within a range of ± 40% with respect to the reference recording power, the recording power is 5.0 mW to 11.8 mW, and when this is divided into 15 stages, recording is performed at about 0.48 mW. It will be recorded while changing the power. The bias power Pb is 2.5 mW to 5.9 mW. By multiplying by the first coefficient K1 of 0.6 to 0.8, the bias power is reduced, and even when recording is performed with a large recording power, the situation where Pb exceeds 8 mW is eliminated and the pseudo recording state of the space signal portion Can be avoided. However, if a larger recording power is supplied, a pseudo recording state of the space signal portion occurs.

  Returning to FIG. 2, the β value is calculated by the β value measuring means in S4. The recorded data is reproduced, and the RF signal generated by the RF amplifier is supplied to the β value measuring circuit 15. The β value measuring circuit 15 holds the peak voltage of the envelope when the RF signal is AC-coupled. The bottom voltage of the envelope of the signal is held, and the hold value is A / D converted and transmitted to the CPU via the bus 18. The CPU calculates and calculates the β value from the A / D converted peak value A and bottom value B using the equation β = (A−B) / (A + B).

  In HD DVD-R, the β value obtained here is a temporary β value. Since the bias power Pb is multiplied by the first coefficient K1, it differs from the β value of the original bias power Pb not multiplied by the first coefficient K1.

  In S5, the optimum power is calculated by the recording power calculation means. The recording power at β≈0 is the optimum recording power. However, in HD DVD-R, the β value calculated at S4 is a provisional β value, and the optimum recording power calculated from the provisional β value is also Temporary recording power. The CPU 19 calculates the original optimum recording power by taking out the second coefficient K2 from the ROM 19 and multiplying the provisional optimum recording power by the second coefficient K2. The optimum bias power can be calculated in the same manner as the recording power.

  FIG. 4 is a diagram showing the relationship between the recording power and the provisional β value in HD DVD-R / DL OPC. The recording power at β≈0 when the bias power Pb is multiplied by the first coefficient K1 is smaller than the original recording power. When the first coefficient K1 is 0.6 to 0.8, it is necessary to multiply the optimum recording power obtained from the temporary β value by the second coefficient K2 (K2> 1). When the first coefficient K1 is 0.6 to 0.8, K2 is 1.3 to 1.5 from the experimental results. The optimum recording power is a value obtained by multiplying the recording power calculated from the temporary β value by, for example, a value of 1.4.

  As described above, by multiplying the standard recording power and bias power by the first coefficient K1, even when the recording power Pw is varied from ± 40% to ± 50%, pseudo recording of the space portion can be prevented. The provisional β value can be calculated from a state in which the recording power and the β value are in a proportional relationship. Further, the optimum recording power and bias power can be calculated by multiplying the recording power and bias power calculated from the temporary β value by the second coefficient K2.

  FIG. 5 is a schematic diagram of a recording data signal and a laser emission waveform when recording on the HD DVD-R / DL in the second embodiment. The recording data is characterized in that when recording data is recorded on the recording optical disk by changing the recording power, data excluding marks with a small bit interval such as 2T is recorded.

  Marks and spaces having small bit intervals such as 2T and 3T are easily affected by the magnitude of the bias power Pb. The mark is not recorded firmly when the bias power Pb is low, and the space is in a pseudo recording state when the bias power Pb is large. In particular, when the space portion is in the pseudo recording state, the proportional relationship between the recording power and the β value is hindered.

  FIG. 6 is a diagram showing the relationship between the recording power and the β value when the 2T mark is removed in HD DVD-R / DL OPC. By not recording the 2T mark and 2T space signals, even if the recording power increases, the state in which the β value increases as the recording power increases as shown in FIG. 12 does not occur. If the 3T mark is not recorded, such a state does not occur.

  As described above, in HD DVD-R / DL, when the optimum recording power is determined using the β value, marks with a small bit interval such as 2T that are easily affected by the magnitude of the bias power Pb are excluded. By writing the data on a trial basis, the linear relationship between the recording power and the β value can be maintained, the recording power can be varied from ± 40% to ± 50%, and the recording power range in OPC can be ensured.

1 is a block diagram showing a configuration of an optical disc apparatus 1 to which the present invention is applied. The flowchart which shows operation | movement of OPC using (beta) value. The schematic diagram of the recording data signal and laser emission waveform at the time of recording on HD DVD-R / DL. The figure which showed the relationship between the recording power and provisional beta value in HD DVD-R / DL OPC. The schematic diagram of the recording data signal and laser emission waveform at the time of recording on HD DVD-R / DL in 2nd Embodiment. The figure which showed the relationship between recording power at the time of excluding 2T mark in OPC of HD DVD-R / DL, and (beta) value. The figure which showed the relationship between the recording power and (beta) value in the OPC of the conventional DVD-R. The schematic diagram of the recording data signal and laser emission waveform at the time of recording on the conventional DVD-R. The figure which showed the relationship between the recording power and beta value in OPC of the conventional HD DVD-R. The schematic diagram of the recording data signal and laser emission waveform at the time of recording on the conventional HD DVD-R.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 2 Optical disk 3 Disk motor 5 Optical pick-up 9 Modulation circuit 10 Laser control circuit 13 Photo detector 14 RF amplifier 15 β value measurement circuit 16 Data reproduction circuit 17 PLL
18 Bus 19 CPU
20 RAM
21 ROM

Claims (6)

Recording means for recording data on a recordable optical disk by changing recording power;
Reproducing means for reproducing the data recorded by the recording means to generate an RF signal;
Β value measuring means for measuring the β value from the RF signal generated by the reproducing means;
Recording power calculating means for calculating and setting recording power based on the β value measured by the β value measuring means,
The recording means records with a recording power obtained by multiplying a standard value of the recording power of the recordable optical disc by a predetermined first coefficient,
The optical disc apparatus, wherein the recording power calculation means sets, as an optimum recording power, a recording power obtained by multiplying a recording power calculated based on the measured β value by a predetermined second coefficient.   2. The optical disc apparatus according to claim 1, wherein the first coefficient is 0.6 to 0.8, and the second coefficient is 1.3 to 1.5. Recording means for recording data on a recordable optical disk by changing recording power;
Reproducing means for reproducing the data recorded by the recording means to generate an RF signal;
Β value measuring means for measuring the β value from the RF signal generated by the reproducing means;
Recording power calculating means for calculating and setting recording power based on the β value measured by the β value measuring means,
The optical disc apparatus is characterized in that the recording means records data excluding marks with small bit intervals when recording data on the recordable optical disc by changing recording power.   4. The optical disc apparatus according to claim 3, wherein the small bit interval mark is a 2T mark.   4. The optical disk apparatus according to claim 3, wherein the marks having a small bit interval are 2T and 3T marks. Recording data on a recordable optical disk by changing the recording power; and
Reproducing the data recorded in the step of recording the data to generate an RF signal;
Measuring a β value from the RF signal generated in the step of generating the RF signal;
Calculating and setting a recording power based on the β value measured in the step of measuring the β value,
In the recording step, recording is performed with a recording power obtained by multiplying a standard value of the recording power of the recordable optical disc by a predetermined first coefficient,
In the step of calculating and setting the recording power, a recording power obtained by multiplying the recording power calculated based on the measured β value by a predetermined second coefficient is set as an optimum recording power. A method for controlling an optical disk apparatus.

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