JP2004127348A - Optical disk recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording device capable of preventing cross-erasure and performing satisfactory recording when information is recorded on an optical recording medium of a CLV system. <P>SOLUTION: In the optical disk recording device, information is recorded on an optical disk having a groove G0 wobbled in a sine wave shape by using a laser beam having a prescribed recording power. The optical disk recording device has a level difference detection means detecting reproducing signal levels obtained from grooves G1 and G2 adjacent to the groove G0 and detecting level differences between the obtained reproducing signal levels and a prescribed level, a clock generation circuit 16 generating a recording clock from the reproducing signal, a recording signal generation circuit 18 generating a recording signal to be recorded synchronizing with the recording clock and a recording means recording the recording signal by the recording power selected based on the level difference and previously set according to the level difference. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc recording apparatus, and more particularly to an optical disc recording apparatus having an information recording groove wobbled at a predetermined frequency and suitable for recording information on a CLV optical recording medium without cross-erasing. It is.
[0002]
[Prior art]
Conventionally, optical disks such as DVD-R and DVD-RW have been known as optical recording media on which information can be recorded and reproduced. In these optical discs, a CLV method for recording information at a constant linear velocity is adopted as a recording format.
[0003]
In an optical disk of the CLV system, a groove for recording / reproducing is wobbled from an inner periphery to an outer periphery at a constant frequency proportional to a recording frequency. When recording / reproducing information on / from this optical disk by the optical disk recording / reproducing apparatus, by detecting the wobbling frequency, the rotation of the spindle motor can be controlled so as to keep the linear velocity constant. It can be generated accurately. As described above, since the linear velocity and the recording clock frequency are constant, when recording information, it is possible to record at any position on the optical disk with the laser power under almost the same conditions.
[0004]
Furthermore, if the calibration area is provided on the optical disc, the recording power condition can be optimized by performing test writing before recording the information, so that the recording quality can be improved ( For example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-6-44563 (pages 2-4, FIG. 3)
[0006]
[Problems to be solved by the invention]
FIG. 14 is a diagram showing wobble phases in grooves adjacent to each other.
FIG. 1 shows a groove G0 formed on an optical recording medium (optical disc) and grooves G1 and G2 adjacent to the groove G0. A land LB is between the groove G0 and the groove G1, and a land LC is between the groove G0 and the groove G2.
The grooves G0, G1, G2 are wobbled.
[0007]
In an optical disc on which recording is performed by the CLV method, as shown in part A of FIG. 14, there are portions where the wobble phases between adjacent grooves (here, grooves G0 and G1) are opposite. At the place where the phase is opposite, the adjacent groove becomes extremely close. Therefore, in such a place, when information (data) is recorded on the groove, the data already recorded on the adjacent groove is erased. This causes a problem of so-called cross erase.
[0008]
This problem can be avoided by setting the laser power condition to a low value in advance so that cross-erase does not occur even in a place where the wobbles have the opposite phase. However, in this case, recording is performed under relatively low power conditions at other places where the phase is not opposite, that is, where there is little concern about cross-erase, and as a result, the recording quality deteriorates. Error rate degradation at the time occurs.
[0009]
Also, in the case where the recording power is optimized in the above-described calibration area, the recording quality can be improved, but the same problem occurs because the cross erase is not considered. Further, when the calibration area and the data area are adjacent to each other, there is a problem that cross-erase may occur even in test writing and recording.
[0010]
Therefore, the present invention has been made in view of the above problems, and provides an optical disc recording apparatus capable of preventing cross-erasing and performing good recording when recording information on an optical recording medium of a CLV system. The purpose is to do.
[0011]
[Means for Solving the Problems]
As a means for achieving the above object, the present invention relates to an optical disk recording apparatus for recording information on an optical disk having an information recording groove G0 wobbled in a sine wave shape at a predetermined frequency with a laser beam having a predetermined recording power. Then, a reproduction signal level obtained from the information recording groove G0 and the information recording grooves G1 and G2 adjacent via the land is detected, and a level difference between the obtained reproduction signal level and a predetermined level is determined. Level difference detecting means for detecting (phase shift detecting circuit 15), clock generating means for generating a recording clock from the reproduced signal (clock generating circuit 16), and a recording signal to be recorded, which is synchronized with the recording clock, is generated. A recording signal generation means (recording data generation circuit 18), and the level difference selected based on the level difference. The response to preset the recording power, the recording means for recording the recording signal (power control circuit 19, the laser drive circuit 17) is an optical disk recording apparatus characterized by comprising a, a.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings by way of preferred examples.
<Example>
First, an optical pickup unit in an embodiment of an optical disk recording device will be described.
[0013]
FIG. 1 is a configuration diagram showing an optical pickup in an embodiment of the optical disk recording apparatus of the present invention.
As shown in FIG. 1, a laser 1 of a pickup (hereinafter also simply referred to as PU) 10 emits a recording or reproducing laser beam R in accordance with a laser driving signal from a laser driving circuit 17 (see FIG. 3) described later. I do.
[0014]
The emitted laser beam R enters the collimator lens 2, exits as parallel light, and enters the diffraction element 3. In the diffraction grating 3, the laser beam R is split into a main beam RBA and two side beams RBB and RBC, and emitted from the diffraction grating 3. After passing through the beam splitter 4, the main beam RBA and the two side beams RBB and RBC are irradiated onto the optical disk 6 by the objective lens 5.
[0015]
The positions of the main beam RBA and the two side beams RBB and RBC on the optical disc 6 are shown in FIG.
FIG. 2 is a diagram showing irradiation positions of the main beam and two side beams on the optical disc.
As shown in FIG. 2, the spot of the main beam RBA is located on a groove G0 formed in the tangential direction of the disk-shaped optical disc 6, and the spots of the two side beams RBB and RBC are radially adjacent to the groove G0. Lands LB and LC, respectively.
[0016]
Returning to FIG. 1, the reflected lights RA, RB and RC corresponding to the main beam RBA and the two side beams RBB and RBC reflected from the optical disk 6 respectively pass through the objective lens 5 and then enter the beam splitter 4 and are detected. The light is reflected toward the lens 7 and emitted.
By the detection lens 7, the reflected light RA corresponding to the main beam RBA is focused on the photodetector 8A, and the reflected lights RB and RC corresponding to the two side beams RBB and RBC are focused on the photodetectors 8B and 8C, respectively.
[0017]
In the photodetector 8A, the reflected light RA corresponding to the main beam RBA is detected by a light receiving unit divided into four in the radial (radial) direction and the circumferential (tangential) direction, and the detection signal SA1 of the groove G0 is detected. , SA2, SA3 and SA4 are output.
In the photodetectors 8B and 8C, the reflected lights RB and RC corresponding to the side beams RBB and RBC are respectively detected by the light receiving portions divided into two corresponding to the radius (radial) direction on the optical disc 6, and the lands LB and RC are detected. LC detection signals SB1, SB2 and SC1, SC2 are output.
[0018]
Next, an optical disc recording apparatus of the present embodiment including the above-described pickup (PU) 10 will be described.
FIG. 3 is a block diagram showing an embodiment of the optical disk recording apparatus of the present invention.
As described above, the PU 10 divides the laser beam R into the main beam RBA and the two side beams RBB and RBC, and irradiates the groove G on the optical disc 6 and the two adjacent lands LB and LC respectively. The reflected lights RA, RB, and RC are respectively detected to output detection signals SA1 to SA4 of the groove G0 and detection signals SB1, SB2 and SC1, SC2 of the lands LB and LC.
[0019]
The detection signals SA1 to SA4 of the groove G0 are output to the reproduction signal detection circuit 11, the focus error detection circuit 12, the tracking error detection circuit 13, and the wobble signal detection circuit 14, respectively.
The detection signals SB1 and SB2 of the land LB and the detection signals SC1 and SC2 of the land LC are output to the tracking error detection circuit 13 and the phase shift detection circuit 15, respectively.
[0020]
The reproduction signal detection circuit 11 detects a reproduction signal by an operation of SA1 + SA2 + SA3 + SA4 and outputs the signal to the reproduction signal processing circuit 50. The reproduction signal processing circuit 50 includes a waveform equalization circuit 42, a binarization circuit 43, a PLL circuit 45, and a decoding circuit 44. The reproduction signal processing circuit 50 outputs reproduction information.
The focus error detection circuit 12 detects a focus error signal by an operation of (SA1 + SA3)-(SA2 + SA4), and outputs this to the servo circuit 41.
[0021]
The tracking error detection circuit 13 calculates a tracking error signal by the D-PP (differential push-pull) method by an operation (where, k is a constant) of (SA1 + SA2-SA3-SA4) -k (SB1-SB2 + SC1-SC2). This is detected and output to the servo circuit 41.
The focus error signal and the tracking error signal sent to the servo circuit 41 are used for focus control and tracking control of the PU 10.
[0022]
In the wobble signal detection circuit 14, after the operation of (SA1 + SA2-SA3-SA4), a wobble signal is extracted by a BPF (bandpass filter) and output to the clock generation circuit 16. The clock generation circuit 16 generates a clock that is phase-synchronized with the wobble signal and has a frequency that is fc / fw times the wobble signal frequency fw (fc is a recording clock frequency). Output to The recording data generation circuit 18 generates recording data based on the recording clock and the recording information sent via the CPU 20, and outputs the recording data to the laser driving circuit 17.
[0023]
The phase shift detection circuit 15 (or 15A) detects a phase shift between a groove wobble irradiated by the main beam RBA from the detection signals SB1, SB2, SC1, and SC2 of the land LB and the land LC and a groove wobble adjacent thereto. .
Hereinafter, this will be described in detail.
FIG. 4 is a configuration diagram showing a first phase shift detecting circuit in the embodiment of the optical disc recording apparatus of the present invention.
As shown in the figure, in the first phase shift detection circuit 15, a radial push-pull signal detection circuit (hereinafter simply referred to as an R-PP signal detection circuit) 21 is provided with a difference (SB1-SB2) between detection signals of the land LB. And outputs it to a BPF (bandpass filter) 23 as a radial push-pull signal PB.
[0024]
The BPF 23 extracts a signal component corresponding to the wobble frequency from the radial push-pull signal PB, and outputs the extracted signal WB to the amplitude detection circuit 25.
The amplitude detection circuit 25 detects the magnitude of the amplitude of the extraction signal WB as an amplitude value MB, and outputs it to the addition circuit 27.
Similarly, a radial push-pull signal detection circuit (hereinafter simply referred to as an R-PP signal detection circuit) 22 calculates a difference (SC1-SC2) between the detection signals of the land LC, and a BPF (bandpass filter) as the radial push-pull signal PC. 24.
[0025]
The BPF 24 extracts a signal component corresponding to the wobble frequency from the radial push-pull signal PC, and outputs an extracted signal WC to the amplitude detection circuit 26.
The amplitude detection circuit 26 detects the magnitude of the amplitude of the extraction signal WC as an amplitude value MC, and outputs it to the addition circuit 27.
The addition circuit 27 adds the amplitude values MB and MC and outputs the result as phase shift information.
[0026]
Here, the principle of the first phase shift detecting circuit will be described with reference to FIGS. 6 to 11 and FIG.
FIG. 6 is a diagram illustrating a groove when the wobble phase between adjacent grooves is the same. FIG. 7 is a graph showing detection signals by the R-PP signal detection circuit when the wobble phases between adjacent grooves are the same.
[0027]
FIG. 8 is a diagram showing grooves when the wobble phase between adjacent grooves is shifted by (1/2) × π. FIG. 9 is a graph showing a detection signal by the R-PP signal detection circuit when the wobble phase between adjacent grooves is shifted by (1/2) × π.
FIG. 10 is a diagram illustrating a groove when the wobble phase between adjacent grooves is opposite to each other. FIG. 11 is a graph showing a detection signal by the R-PP signal detection circuit when the wobble phase between adjacent grooves is opposite to each other.
FIG. 12 is a graph showing the relationship between the phase shift and the amplitude values MB and MC of the radial push-pull signal.
[0028]
As shown in FIG. 6, when there is no phase shift between the wobbles of adjacent grooves (for example, the grooves G0 and G1), that is, when the wobbles of the adjacent grooves have the same phase, the radial push of the lands LB and LC is performed. The pull signals PB and PC are detected as signals as shown in FIGS. 7A and 7B, respectively.
[0029]
As shown in FIG. 8, when the phase between wobbles of adjacent grooves (for example, grooves G0 and G1) is shifted by (1/2) × π (π is a wobble cycle), the radial push-pull signals PB and PC are changed. As shown in FIGS. 9A and 9B, respectively, the signal amplitude becomes smaller.
Further, as shown in FIG. 10, when the phase between the wobbles of the adjacent grooves (for example, the groove G0 and the groove G1) is shifted by π, that is, becomes opposite phase, the radial push-pull signals PB and PC are respectively shown in FIG. (A) and almost no detection as shown in FIG. 11 (b).
[0030]
As described above, as the phase shift between wobbles increases, the signal amplitudes of the radial push-pull signals PB and PC decrease. When the wobble is formed in a sine wave shape, the phase shift (shift) and the amplitude value As shown in FIG.
Amplitude value MB = MC = s × | cos (t / 2) | (s is a constant, t is the amount of phase shift)
The relationship is almost similar to
Therefore, the phase shift amount can be detected by detecting the amplitude value MB or MC.
[0031]
The first phase shift detection circuit 15 is configured to detect the phase shift by adding the amplitude values MB and MC of the radial push-pull signal PB and the PC in order to increase the detection accuracy. It is possible to detect the phase shift amount only by detecting the amplitude value of one of the radial push-pull signals PB and PC,
A phase shift detection circuit having such a configuration may be used.
[0032]
Next, a description will be given of a second phase shift detecting circuit in the optical disc recording apparatus of the present embodiment.
FIG. 5 is a block diagram showing a second phase shift detecting circuit in the embodiment of the optical disk recording apparatus of the present invention.
As shown in the figure, in the second phase shift detection circuit 15A, a radial push-pull signal detection circuit (hereinafter simply referred to as an R-PP signal detection circuit) 31 detects a difference (SB1-SB2) between detection signals of the land LB. An arithmetic operation is performed to obtain a radial push-pull signal PB, which is output to the delay circuit 33.
[0033]
A radial push-pull signal detection circuit (hereinafter simply referred to as an R-PP signal detection circuit) 32 calculates a difference (SC1−SC2) between the detection signals of the land LC, obtains a radial push-pull signal PC, and sends this to the addition circuit 34. Output.
The delay circuit 33 corrects a temporal shift between the radial push-pull signal PB and the radial push-pull signal PC caused by a difference in the irradiation position of the side beam RBB and the side beam RBC on the optical disk 6, and converts the radial push-pull signal PB. After being synchronized with the radial push-pull signal PC, the signal is output to the adder circuit 34 as a radial push-pull signal PBD.
[0034]
The adding circuit 34 adds the radial push-pull signal PBD and the radial push-pull signal PC after synchronization, obtains an addition signal PS, and outputs this to a BPF (bandpass filter) 35.
The BPF 35 extracts a signal component corresponding to the wobble frequency from the added signal PS, and outputs the extracted signal WS to the amplitude detection circuit 36.
The amplitude detection circuit 36 detects the magnitude of the amplitude of the extraction signal WS as an amplitude value MS and outputs it as phase shift information.
[0035]
Here, the principle of the second phase shift detection circuit 15A will be described with reference to FIGS. 6 to 11 and FIG.
As described in the first phase shift detecting circuit, when the wobbles of adjacent grooves (for example, the grooves G0 and G1) have the same phase as shown in FIG. 6, the radial push-pull signal PB And PC are detected as signals as shown in FIGS. 7A and 7B, respectively, and the added signal PS is detected as a signal as shown in FIG. 7C.
[0036]
Also, as shown in FIG. 8, when the phases of wobbles of adjacent grooves (for example, grooves G0 and G1) are shifted by (1/2) × π (π is a wobble cycle), the radial push-pull signals PB and PC 9 (a) and FIG. 9 (b), respectively, so that the added signal PS has a smaller signal amplitude as shown in FIG. 9 (c).
Further, as shown in FIG. 10, when the phases of the wobbles of the adjacent grooves (for example, the grooves G0 and G1) are shifted by π, that is, when the phases become opposite phases, the radial push-pull signals PB and PC become the signals of FIG. Since almost no detection is made as shown in FIGS. 11A and 11B, the addition signal PS is hardly detected as shown in FIG. 11C.
[0037]
Since the signal amplitudes of the radial push-pull signals PB and PC decrease as the phase shift between wobbles increases, the signal amplitude of the added signal PS also decreases. When formed in a sine wave shape, the relationship between the phase shift t and the amplitude value MS of the addition signal PS is substantially proportional as shown in FIG.
Accordingly, the phase shift amount can be detected by detecting the amplitude value MS of the addition signal PS. Further, since the amplitude value MS and the phase shift amount have a substantially proportional relationship, the first phase shift The detection circuit 15 makes it easier to obtain the phase shift amount.
[0038]
In the above description, the radial push-pull signal PB is passed through the delay circuit. However, when the radial push-pull signal PC is temporally ahead of the radial push-pull signal PB, the radial push-pull signal PB is used. The configuration may be such that the PC passes through the delay circuit.
[0039]
Next, returning to FIG. 3 again, the optical disk recording device will be described.
The phase shift information output from the phase shift detection circuit 15 (or 15A) is sent to the CPU 20.
The CPU 20 sets the recording power of the laser with a table value or a calculated value set in advance based on the phase shift information at the time of recording information (data), and sets a predetermined reproduction power at the time of reproduction.
[0040]
Here, if the phase shift amount is large, the table value or the calculation value by the calculation formula indicates that there is a portion close to the adjacent groove and the possibility of cross-erase increases, so that the recording power is reduced. In addition, when the phase shift amount is small, the possibility of the cross-erase as described above is small. Therefore, the recording power is set in advance so as to increase the recording power in order to improve the recording quality.
[0041]
An example of the setting value of the recording power will be described below.
In the case of a table value, if the wobble period is π according to the phase shift amount t,
(1) When | t | ≦ (１ ／) π, the recording power is the maximum power Pmax.
(2) When (1/4) π <| t | ≦ (2/4) π, the recording power is set to Pmax × 0.96.
(3) When (2/4) π <| t | ≦ (3/4) π, the recording power is set to Pmax × 0.92.
(4) When (3/4) π <| t | ≦ (4/4) π, the recording power is set to Pmax × 0.84.
In this way, the recording power according to the phase shift amount is set and set as a table value.
[0042]
In the case of the calculation formula, if the wobble period is π according to the phase shift amount t,
(1) When 0 ≦ | t | ≦ (1/4) π, the recording power is the maximum power Pmax (when t = 0) (point A) to Pmax × 0.98 (| t | = (1/4) ) Π) (point B). Here, when t takes an intermediate value between the points A and B, the recording power value corresponding to t on the straight line connecting the points A and B is set as the recording power value.
(2) When (1/4) π ≦ | t | ≦ (2/4) π, the recording power is Pmax × 0.98 (when | t | = (1/4) π) (point B) Pmax × 0.94 (when | t | = (2/4) π) (point C). Here, when t takes an intermediate value between the points B and C, the recording power value corresponding to t on the straight line connecting the points B and C is set as the recording power value.
[0043]
(3) When (2/4) π ≦ | t | ≦ (3/4) π, the recording power is Pmax × 0.94 (when | t | = (2/4) π) (point C) to Pmax × 0.88 (when | t | = (3/4) π) (point D). Here, when t takes an intermediate value between the points C and D, the recording power value corresponding to t on a straight line connecting the points C and D is set as the recording power value.
(4) When (3/4) π ≦ | t | ≦ (4/4) π, the recording power is Pmax × 0.88 (when | t | = (3/4) π) (point D) to Pmax × 0.80 (when | t | = (4/4) π) (point E). Here, when t takes an intermediate value between the points D and E, the recording power value corresponding to t on the straight line connecting the points D and E is set as the recording power value.
With such an approximate expression, the recording power is calculated and set according to the phase shift amount.
[0044]
The recording power set value or the reproduction power set value set as described above is output from the CPU 20 to the power control circuit 19.
The power control circuit 19 controls the laser drive circuit 17 so as to have a recording power or a reproduction power based on the set value.
The laser drive circuit 17 generates a laser drive signal with the recording data from the record data generation circuit 18 and the recording power controlled by the power control circuit 19 during recording, and drives the laser with the reproduction power controlled by the power control circuit 19 during reproduction. Generate a signal.
The laser 1 of the PU 10 is driven by these laser drive signals to perform recording or reproduction on the optical disk 6. As a result, cross-erase at the time of recording is prevented, and good recording is realized.
[0045]
In the above description, the recording power of the laser is set by a table value or a calculation formula in accordance with the phase shift information (amount). Alternatively, the upper limit value or the upper limit value and the lower limit value of the recording power in test writing may be set by a table value or a calculation formula.
In the above embodiment, a general disk-shaped optical disk has been described, but a card-shaped optical recording medium such as a digital card may be used.
[0046]
【The invention's effect】
As described above, the optical disc recording apparatus of the present invention detects the reproduction signal level obtained from the information recording groove and the adjacent information recording groove via the land, and determines the obtained reproduction level with respect to a predetermined level. Level difference detecting means for detecting a level difference between signal levels, clock generating means for generating a recording clock from the reproduction signal, recording signal generating means for generating a recording signal to be recorded, synchronized with the recording clock, Recording means for recording the recording signal with the recording power preset according to the level difference selected based on the level difference, thereby recording information on an optical recording medium of a CLV system. In this case, there is an effect that it is possible to provide an optical disc recording apparatus capable of preventing cross erase and performing good recording.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating an optical pickup in an embodiment of an optical disc recording apparatus according to the present invention.
FIG. 2 is a diagram showing irradiation positions of a main beam and two side beams on an optical disk.
FIG. 3 is a configuration diagram showing an embodiment of an optical disk recording device of the present invention.
FIG. 4 is a configuration diagram showing a first phase shift detecting circuit in the embodiment of the optical disc recording apparatus of the present invention.
FIG. 5 is a configuration diagram showing a second phase shift detecting circuit in the embodiment of the optical disc recording apparatus of the present invention.
FIG. 6 is a diagram illustrating a groove when wobble phases between adjacent grooves are the same.
FIG. 7 is a graph showing a detection signal by an R-PP signal detection circuit when wobble phases between adjacent grooves are the same.
FIG. 8 is a diagram showing grooves when the wobble phase between adjacent grooves is shifted by (1/2) × π.
FIG. 9 is a graph showing a detection signal by an R-PP signal detection circuit when a wobble phase between adjacent grooves is shifted by (1/2) × π.
FIG. 10 is a diagram illustrating a groove when wobble phases between adjacent grooves are opposite phases.
FIG. 11 is a graph showing a detection signal by an R-PP signal detection circuit when wobble phases between adjacent grooves are opposite phases.
FIG. 12 is a graph illustrating a relationship between a phase shift and amplitude values MB and MC of a radial push-pull signal.
FIG. 13 is a graph showing a relationship between a phase shift and an amplitude value MS of a radial push-pull signal.
FIG. 14 is a diagram showing a wobble phase between adjacent grooves.
[Explanation of symbols]
Reference Signs List 1 laser, 2 collimator lens, 3 diffraction grating, 4 beam splitter, 5 objective lens, 6 optical disk, 7 detection lens, 8A, 8B, 8C photodetector, 10 pickup, 11 reproduction Signal detection circuit, 12: focus error detection circuit, 13: tracking error detection circuit, 14: wobble signal detection circuit, 15, 15A: phase shift detection circuit, 16: clock generation circuit, 17: laser drive circuit, 18: recording data Generation circuit 19 Power control circuit 20 CPU R-PP signal detection circuit 22 R-PP signal detection circuit 23 BPF 24 BPF 25 Amplitude detection circuit 26 Amplitude detection circuit , 27 addition circuit, 31 R-PP signal detection circuit, 32 R-PP signal detection circuit, 33 delay circuit, 34 addition circuit, 35 BPF, 6 ... amplitude detection circuit, 41 ... servo circuit, 42 ... waveform equivalent circuit, 43 ... binarizing circuit, 44 ... decoder circuit, 45 ... PLL circuit, 50 ... reproduction signal processing circuit, 100, 100A ... optical disc recording apparatus.

Claims (1)

An optical disk recording apparatus for recording information on an optical disk having an information recording groove wobbled in a sine wave shape at a predetermined frequency with a laser beam having a predetermined recording power,
Level difference detecting means for detecting a reproduction signal level obtained from the information recording groove and an adjacent information recording groove via a land, and detecting a level difference of the obtained reproduction signal level with respect to a predetermined level; ,
Clock generating means for generating a recording clock from the reproduction signal;
Recording signal generating means for generating a recording signal to be recorded, which is synchronized with the recording clock,
An optical disk recording apparatus, comprising: a recording unit that records the recording signal with the recording power that is selected based on the level difference and that is set in advance according to the level difference.

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