JP3057875U - Optical disk recording device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In an optical disk recording apparatus for recording data on a write-once optical disk or an RW type optical disk, it is possible to grasp the recording sensitivity state of the optical disk in addition to the criterion of the optimum power level based on the β value. By providing such a determination criterion, the optimum power level can be accurately detected, and as a result, more stable recording characteristics can be obtained. SOLUTION: In addition to a β value obtained from a maximum value and a minimum value of an RF signal, a modulation degree of the RF signal (11 Tp-p / 11) is obtained.
Ttop × 100) was used as a criterion for determining the optimum power level. As a result, the state of the recording sensitivity of the optical disc can be grasped, and when the recording sensitivity of the optical disc is poor,
It is possible to avoid a recording operation in which the recording characteristics are poor.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to an optical disc recording apparatus for recording various data on an optical disc, and more particularly to a technique for optimizing a recording laser power.

[0002]

[Prior art]

 Conventionally, a write-once optical disc (CD (Compact Disk) -WO (Write Once)) has been known as an optical disc on which data can be written only once. A rewritable (RW) disc is known as a rewritable optical disc. An optical disk device for recording data on an optical disk such as these generally has a power calibration function for detecting an optimum power level of a recording laser beam. When recording data, an OPC (Optical Mum) is used. A power calibration operation called Power Control) is performed.

[0003] An OPC operation in a conventional optical disk device will be described with reference to FIGS. As shown in FIG. 4, on the recording surface of the optical disc 2, a data area 46 for storing various data and a test recording area 50 (PCA: Power Calibration Area, hereinafter referred to as PCA) for detecting the optimum power of the laser beam. , PCA) are provided. The PCA 50 includes a test area 50a and a count area 50b, and the test area 50a includes 100 partitions P001 to P100. Each partition P001 to P100 is composed of 15 frames F1 to F15. In one OPC operation, one of the partitions P001 to P100 is used, and the test signal is applied to the fifteen frames F1 to F15 constituting the partitions P001 to P100 with the laser power of 15 steps. Record This test signal is an EFM (Eight to Fourteen Modulation) signal composed of a pulse train having a time width of 3 to 11 times the reference time width T, and a pit having 9 different lengths is recorded in a frame. Has become.

Next, by irradiating these frames F1 to F15 with laser light and detecting reflected light from the optical disk 2, a test signal is reproduced and respective reproduced signals (hereinafter referred to as RF signals) are reproduced. The maximum value, the minimum value, and the DC average value of the reproduced signal are measured, and the β value is calculated using these values. Here, three of the 15 RF signals are shown in FIG. These three waveform diagrams show that the recording laser power Pw at the PCA is smaller than the reference power Po, larger than the reference power Po, and larger than the reference power Po in the order of left, center, and right. Shows the RF signal when test recording was performed. The signal with the longest period is a signal due to the longest pit formed by the EFM signal having a time width 11 times the reference time width T (hereinafter, referred to as an 11T signal). This is a short pit formed by an EFM signal having a time width three times the reference time width T (hereinafter, referred to as a 3T signal). Numeral 60 indicates the RF signal value based on the reflected light from the mirror surface of the optical disk 2 having no pits. The peak value of the 11T signal coincides with the RF signal value 60 of this mirror surface. RFDC indicates the average value of the RF signal. A1 is the absolute value of the signal difference between the maximum value of the RF signal (maximum value of the 11T signal) and RFDC, and A2 is the absolute value of the signal difference between the minimum value of the RF signal (minimum value of the 11T signal) and RFDC. Indicates the value.

When these A1 and A2 are measured, the β value is calculated by the following equation (1), and the laser power that records the portion where the β value is close to the optimum is determined as the optimum power level. Used as the laser power to be recorded on β value (%) = ((A1 + A2) / (A1−A2)) × 100 (1)

As shown in the waveform diagram on the left side of FIG. 5, when the power level PW of the laser beam is lower than the reference power level P0, the RF signal amount of the 3T signal increases, and the RFDC rises. This is because the lower the power level PW, the smaller the depth of the pits formed on the optical disk 2 and the greater the amount of reflected light. On the other hand, as shown in the waveform diagram on the right side of FIG. 5, when the power level PW increases, deep pits are formed on the optical disk 2 and the amount of reflected light decreases, so that the RF signal amount of the 3T signal decreases. RFDC drops. As a result, the values of A1 and A2 change, and the β value changes from low to high in proportion to the height of the recording laser power.

In this type of power calibration (OPC) method, in order to detect an optimum power level, one partition is divided into a plurality of areas, and a test recording operation is performed on the plurality of test areas a plurality of times. In addition, there is known a method of calculating a β value and setting a power level at which the finally obtained β value matches a target value as an optimum power level (for example, see JP-A-7-287847). ). Similarly, in order to detect the optimum power level, an area having two frames as one unit is provided, and a long test signal is test-recorded in this area. There is known a method for obtaining a β value more accurately by reducing the size (for example, Japanese Patent Application Laid-Open No. 5-144004).

[0008]

[Problems to be solved by the invention]

 However, in any of the OPC methods described above, since only the β value is used as a criterion for determining the optimum power level, for example, as shown in FIG. On the other hand, even when OPC is performed, the optimum power may be obtained. However, if the recording operation is performed on the data area 46 with that power, the final recording characteristics (jitter, block error rate, etc.) deteriorate because the amplitude of the reproduced RF signal is low, and the recorded signal cannot be reproduced. May disappear.

The present invention has been made in order to solve the above-mentioned problem, and can capture the state of the recording sensitivity of an optical disk in addition to the conventional criterion for determining the optimum power level based on the β value. It is an object of the present invention to provide an optical disk recording device that can accurately detect an optimum power level by providing such a criterion, and as a result, can obtain more stable recording characteristics.

[0010]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention records a test signal in a power calibration area of an optical disk by using laser beams of two or more different power levels, and reproduces the test signal to produce a laser beam. A power calibration function is provided to detect the optimum power level of the optical disc, and the power calibration is performed in an optical disc recording device that records various data in the data area of the optical disc using the laser beam of the optimum power level detected by this power calibration operation. A test recording means for recording a test signal in the power calibration area with laser beams having different power levels at different stages during operation, and a test from the power calibration area where test recording is performed by the test recording means. Signal reproducing means for reproducing the signal and outputting the reproduced signal, and measuring the maximum value, the minimum value and the DC average value of the reproduced signal from the signal reproducing means at each power level, An optimum power level determining means for performing a predetermined operation using the local minimum value and the DC average value, comparing the operation value with a preset target value, and determining a power level in which the two coincide with each other as an optimum power level; A comparison means for measuring the modulation degree of the reproduced signal with respect to the optimum power level determined by the optimum power level determination means, and comparing the modulation degree with a preset reference value, based on a comparison result by the comparison means. Means for determining whether or not to perform a recording operation on the data area of the optical disk using the laser beam having the optimum power level, and receiving an instruction from the determination means. Data recording means for performing a recording operation on the data area of the optical disc by using the laser beam of the optimum power level, and the judgment means determines the data only when the modulation degree is equal to or more than the reference value. It instructs the recording means to perform a recording operation.

In this configuration, the calculated value obtained from the maximum value, the minimum value, and the DC average value of the reproduction signal is compared with a preset target value, and the power level at which the two values match is determined as the optimum power level. I do. Next, the modulation level of the reproduction signal for the optimum power level is measured, and the modulation level is compared with a reference value. If the modulation level is equal to or higher than the reference value, the laser beam having the optimum power level is used. Performs recording operation on the data area of the optical disk. As described above, in addition to the calculated value obtained from the maximum value, the minimum value, and the DC average value of the reproduction signal, the degree of modulation is used as a criterion for determining the optimum power level, so that the recording sensitivity state of the optical disk can be captured. It becomes possible.

If the modulation degree of the reproduction signal for the above-mentioned optimum power level is less than the reference value, the optimum power level is multiplied by a predetermined coefficient so that the modulation degree of the reproduction signal becomes higher than the optimum power level. Correction means may be further provided, and the data recording means may perform a recording operation on the data area of the optical disc using the laser beam having the power level corrected by the optimum power level correction means.

In this configuration, when the amplitude of the reproduced signal at the time of the test recording operation is small and the modulation degree of the reproduced signal for the optimum power level is less than the reference value, the reproduction signal is not compared with the optimum power level. The correction is performed by applying a predetermined coefficient so that the modulation degree becomes high, and the recording operation is performed on the data area of the optical disk by using the laser light of the corrected power level.

The test recording means has a power level higher than the optimum power level determined by the optimum power level determining means when the modulation degree of the reproduced signal for the optimum power level is less than the reference value. The test signal may be recorded again in the power calibration area using laser light.

In this configuration, when the amplitude of the reproduction signal at the time of the test recording operation is small and the modulation degree of the reproduction signal for the optimum power level is less than the reference value, the power level is higher than the optimum power level. Perform the test recording operation again using the laser beam. This makes it possible to accurately detect the optimum power level.

Further, the test recording means records the test signal using an EFM signal composed of pulse signals having different time widths from each other, and the comparing means determines the optimum power level determined by the optimum power level determining means. It is desirable that the modulation degree of the reproduction signal having the longest time width is measured and the modulation degree of the reproduction signal is compared with a preset reference value. In this configuration, the degree of modulation in the reproduction signal having a long time width, which is most significantly affected by the recording sensitivity of the optical disk, is used as the criterion for determining the optimum power level, so that the optimum power level can be accurately detected.

[0017]

[Embodiment of the invention]

 Hereinafter, an optical disk recording device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the electrical configuration of the optical disk recording device. The optical disk recording device 1 has a power calibration function for detecting an optimum power level of a recording laser beam, and can record various data on the optical disk 2 using the laser beam having the optimum power level. is there. A recording control circuit 4 is connected to a central processing unit 3 (hereinafter, referred to as CPU: determining means) for controlling the entire recording apparatus 1. The recording control circuit 4 is configured to control a control signal from the CPU 3 and an encoder. In response to the test signal from the control circuit 5, a drive control signal is output to the laser drive circuit 6 and the servo circuit 7. The encoder 5 converts the information to be written into an EFM signal composed of a pulse train having a time width 3 to 11 times the reference time width, and outputs the EFM signal. The optical pickup 8 has a built-in semiconductor laser (not shown), condenses the laser light from the semiconductor laser, irradiates the target position on the optical disk 2 with the laser light, and converts the reflected light into an electric signal. This is a unit that converts the information into information and reproduces the information. The semiconductor laser of the optical pickup 8 is controlled by controlling the power supply from a laser drive circuit 6, and the position of the optical pickup 8 is controlled by a servo circuit 7. These recording control circuit 4, encoder 5, laser drive circuit 6, servo circuit 7, and optical pickup 8 constitute the test recording means and data recording means of the present invention.

The RF amplifier circuit 10 (signal reproducing means) amplifies and demodulates an electric signal read by the optical pickup 8. The RF signal (reproduced signal) from the RF amplifier circuit 10 is a β detection circuit. It is sent to the 20 and 11T modulation degree detection circuit 30. The β value detected by the β detection circuit 20 is compared with a target β value (target value) in a β value comparison circuit 21. The β detection circuit 20 and the β value comparison circuit 21 It constitutes the optimal power level determining means of the invention. The detection value detected by the 11T modulation degree detection circuit 30 is compared with a reference value SV in an 11T modulation degree comparison circuit 31. These 11T modulation degree detection circuit 30 and 11T modulation degree comparison circuit 31 constitutes the comparison means of the present invention. The details of the operations of the β detection circuit 20, the β value comparison circuit 21, the 11T modulation degree detection circuit 30, the 11T modulation degree comparison circuit 31, and the like will be described later. The CPU 3 is also connected to a rotation control circuit 13 for controlling a spindle motor 12 for rotating the optical disk 2, and a CD tray open / close switch 14 for inserting and removing a tray on which the optical disk 2 is mounted.

Next, FIG. 2 is a flowchart showing the OPC operation of the optical disk recording apparatus 1, and FIG. 3 shows an RF signal output from the RF amplifier circuit 10. The OPC operation of the device 1 will be described. The optical disc 2 has a test area 50a composed of 100 partitions P001 to P100 as shown in FIG. 4 described above, and each partition P001 to P100 is composed of 15 frames F1 to F15. The OPC operation is performed when a write instruction to the data area 46 is issued.

When the optical disk 2 is placed on the tray and the CD tray open / close switch 14 is operated to set the optical disk 2, the CPU 3 first sets the laser power to an initial value, and then sets the laser power to the test area 50a of the PCA. A search is performed, and a test signal is recorded on the fifteen frames F1 to F15 constituting the partition P001 with laser light having 15 power levels (S1). The power levels at this time are power levels PW1 to PW15 in 15 steps obtained by dividing the output between the maximum value and the minimum value of the laser light into 15 parts. Next, the test signals recorded in these frames F1 to F15 are read back, and the A1 and A2 at the respective power levels PW1 to PW15 are measured by the β detection circuit 11, and the β value is calculated from the above equation (1). Calculated based on The β value is compared with a preset target β value in the β value comparison circuit 21, and the power level at which the two values match is determined as the optimum power level (S3). The above operation is the same as the conventional OPC operation.

Next, in the 11T modulation degree detection circuit 30, the modulation degree of the reproduction signal (11T signal) having the longest time width with respect to the optimum power level (hereinafter referred to as 11T modulation degree) is calculated based on the following equation (2). (S4). 11T modulation degree = 11Tp-p / 11Ttop × 100 (%) (2) Here, 11Tp-p is a signal in the state 61 where no light returns at all with the RF signal 60 in the mirror surface portion of the optical disk 2 having no pits. 11Ttop indicates the signal difference between the maximum value of the RF signal and the no-signal level (GND level).

Next, the 11T modulation factor is compared with a preset reference value SV in an 11T modulation factor comparison circuit 31 (S5). Here, as shown in FIG. 3A, when the amplitude of the RF signal is large and the 11T modulation degree is equal to or larger than the reference value (YES in S5), it is determined that the recording sensitivity of the optical disc 2 is good. Then, it instructs the recording control circuit 4 to record various data in the data area of the optical disk 2 with the laser beam of the optimum power level, and performs the recording operation (S6). On the other hand, as shown in FIG. 3B, when the RF signal is small and the 11T modulation degree is less than the reference value (NO in S5), the recording sensitivity of the optical disc 2 is not good, and it is determined in S3. At the optimum power level, an NG determination is made that recording with good recording characteristics cannot be performed on the optical disc 2. Here, if this NG determination is the first time (YES in S7), a laser beam having a power level higher than the optimum power level is selected (S9), the process returns to S2, and the OPC operation is performed again. If the second NG determination is made in S7 (NO in S7), it is determined that an OPC operation error is not possible to detect the optimum power level (S8), and the recording operation for the data area is performed. Do not do.

As described above, in addition to the β value, the 11T modulation degree is used as a criterion in the OPC operation, so that the recording sensitivity state of the optical disk 2 can be grasped. Therefore, when the recording sensitivity of the optical disk 2 is extremely low, it is possible to avoid a recording operation in which recording characteristics such as jitter and block error rate are deteriorated.

Further, when the 11T modulation degree of the RF signal for the optimum power level is less than the reference value SV, the test recording operation is performed again using a power level higher than the optimum power level. Even if the recording sensitivity of the optical disk 2 is not good, the optimum power level can be detected more accurately. Further, since the 11T modulation degree, which is most significantly affected by the recording sensitivity of the optical disc 2, is used as the criterion for determining the optimum power level, the optimum power level can be detected accurately.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, when the 11T modulation degree is less than the reference value SV, the test recording operation is performed again by using a laser beam having a power level higher than the above-mentioned optimum power level. However, the present invention is not limited to this. For example, the optical power is corrected by applying a predetermined coefficient so that the modulation degree of the RF signal becomes higher than the optimum power level, and the laser beam having the corrected power level is used for the optical disc. The recording operation may be performed on the second data area 46. As a result, as described above, when the recording sensitivity of the optical disc 2 is extremely low, it is possible to avoid a recording operation in which the recording characteristics become poor.

[0026]

[Effect of the invention]

 As described above, according to the optical disk recording apparatus of the present invention, in addition to the maximum value and the minimum value of the reproduction signal, the modulation factor is used as a criterion during the power calibration operation. Therefore, it is possible to avoid a recording operation in which the recording characteristics become poor.

When the modulation degree of the reproduction signal for the optimum power level is less than the reference value, the test recording operation is performed again using a power level higher than the optimum power level, thereby achieving recording. It is possible to accurately detect the optimum power level even for an optical disk with low sensitivity.

Further, correction is performed by applying a predetermined coefficient to the optimum power level so as to increase the modulation degree of the reproduction signal, and the data of the optical disk is obtained by using the laser light of the corrected power level. By performing the recording operation on the area, when the recording sensitivity of the optical disc is low, it is possible to avoid the recording operation in which the recording characteristics are deteriorated.

Further, since the degree of modulation in the reproduction signal having the longest time width, which is most significantly affected by the recording sensitivity of the optical disk, is used as a criterion for determining the optimum power level, it is possible to accurately detect the optimum power level. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an optical disc recording device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an OPC operation of the optical disc recording device.

FIGS. 3A and 3B are waveform diagrams of an RF signal reproduced during an OPC operation, respectively.

FIG. 4 is a diagram illustrating an OPC operation on a test area of the optical disc according to the present invention and a conventional optical disc.

FIG. 5 is a waveform diagram of an RF signal reproduced during a conventional OPC operation.

FIG. 6 is a waveform diagram of an RF signal for explaining a conventional problem.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical disk recording device 2 Optical disk 3 CPU (determination means, optimal power level correction means) 4 Recording control circuit (test recording means, data recording means) 5 Encoder (test recording means, data recording means) 6 Laser drive circuit (test recording means) 7 Servo circuit (test recording means, data recording means) 8 Optical pickup (test recording means, data recording means) 10 RF amplifier circuit (signal reproducing means) 20 β detection circuit (optimum power level determining means) 21 β value comparison circuit (optimal power level determination means) 30 11T modulation degree detection circuit (comparison circuit) 31 11T modulation degree comparison circuit (comparison circuit) 46 data area 50 power calibration area P001 to P100 Partition F1 to F15 Frame SV Reference value

Claims (4)

[Utility model registration claims] A power for detecting an optimum power level of a laser beam by recording a test signal in a power calibration area of an optical disc with laser beams having two or more different power levels and reproducing the test signal. An optical disc recording apparatus that has a calibration function and records various data in a data area of the optical disc using a laser beam having an optimum power level detected by the power calibration operation; Test recording means for recording a test signal in the power calibration area with laser light having a plurality of power levels; and reproducing the test signal from the power calibration area on which test recording has been performed by the test recording means. A signal reproducing means for outputting a reproduced signal, and measuring a maximum value, a minimum value and a DC average value of the reproduced signal from the signal reproducing means at each power level, and measuring these maximum value, minimum value and DC An optimal power level determining means for performing a predetermined operation using the average value, comparing the operation value with a preset target value, and determining a power level at which the two values coincide with each other as an optimum power level; A comparison unit that measures a modulation degree of the reproduction signal for the optimum power level determined by the level determination unit, and compares the modulation degree with a preset reference value; based on a comparison result by the comparison unit, Determining means for determining whether or not to perform a recording operation on a data area of the optical disk using a laser beam having an optimum power level; Data recording means for performing a recording operation on the data area of the optical disc by using the laser beam having the optimum power level, wherein the determining means determines that the modulation degree is equal to or more than a reference value. An optical disk recording apparatus for instructing the data recording means to perform a recording operation. 2. When the modulation degree of the reproduction signal for the optimum power level is less than a reference value, the optimum coefficient is multiplied by a predetermined coefficient so that the modulation degree of the reproduction signal is higher than the optimum power level. Power level correcting means, wherein the data recording means performs a recording operation on a data area of the optical disk by using a laser beam having a power level corrected by the optimum power level correcting means. The optical disk recording device according to claim 1, wherein: 3. The test recording device according to claim 1, wherein the modulation level of the reproduction signal with respect to the optimum power level is less than a reference value, the power level being higher than the optimum power level determined by the optimum power level determining device. 2. The optical disc recording apparatus according to claim 1, wherein a test signal is recorded again in the power calibration area using a laser beam having the following. 4. The test recording means records the test signal by an EFM signal composed of pulse signals having different time widths from each other, and the comparing means comprises an optimum power level determined by the optimum power level determining means. 4. The method according to claim 1, wherein a modulation degree of the reproduction signal having the longest time width is measured, and the modulation degree of the reproduction signal is compared with a preset reference value. An optical disk recording apparatus according to any one of claims 1 to 3.