JP3271575B2 - Optical disk recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording apparatus of a mark length recording system for recording information by forming pits by irradiating a recording surface of an optical disk with laser light.
The recording signal quality (jitter, deviation, error rate, etc.) in the case of performing recording (high-speed recording) at a speed higher than the standard speed (= 1 × speed) is improved.

[0002]

2. Description of the Related Art As one of the recording methods of a writable optical disk, there is a CD-WO (CD Write Once) standard. According to the CD-WO standard, information is 3T to 11T
(1T is 1 / 4.3218 MHz = 231.
3 ns, 2x speed: 1/2 of 1x speed, 4x speed: 1/4 of 1x speed, 6x speed: 1/6 of 1x speed, etc. Is recorded on the optical disc in combination. As shown in FIG. 2, the beam power of the recording laser beam of the CD-WO disc is set to the top power in the section where pits are formed, and is set to the bottom power in the section where lands are formed. in this case,
If a pit is formed while maintaining the top power for the length of the pit, the pit is actually formed about 1T longer due to the residual heat of the laser beam. Therefore, as a laser modulation method at the time of recording, a so-called (n−K) T + α (nT) strategy is used to shorten the duration of the top power by about KT from the pit length nT to be formed. Pit formation is performed. Note that α (nT)
Is the fine adjustment amount for each pit length. Α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧ α (11T) (α (3T)>
α (11T)).

As another strategy of the laser modulation method at the time of recording, (n−K) T + α (nT) −β (mT), where β (mT) is a correction amount for each land length immediately before is also proposed. Have been. Further, as shown in FIG. 3, the applicant of the present invention disclosed in Japanese Patent Application No. 8-233596 that, at the beginning of the start of the top power, the top power value was increased by 1 mW in 1.5T time, so that the jitter in the high-speed recording was increased. It is proposed to prevent the deterioration of the pit deviation (the amount of deviation from the regular pit length).

[0004]

The fine adjustment amount α (nT),
The time resolution (minimum time change width) of β (mT) is determined by the oscillation frequency of the crystal oscillator used. For example, 33.8M
33.8 × 4 × (98/9
6) The time resolution when a 276 MHz clock is created by × 2 circuit processing is 1/276 MHz = 3.6 n
s. When the recording speed magnification is low, such a time resolution is sufficient. However, when the recording speed magnification is high, the time per 1T is short, so that the ratio of the time resolution to the length of 1T is relatively large. For this reason, α should be set so that the jitter,
In some cases, it became impossible to set the values of (nT) and β (mT).

For example, when recording at 6 × speed, 1
The length of T is 231.3 ns / 6 = 38.55 ns, and the time resolution 3.6 ns is 3.6 / 38.55 = 0.
09T. That is, α (nT) and β (mT) are 0.0
It can be set in 9T steps. Under this time resolution, the basic strategy is (n−0.2) T + α (n
T) -0.09T, the measurement results of jitter of 3T long land and deviation of 3T long pit when recording at a 6 × speed on a phthalocyanine disc of a certain manufacturer using the laser modulation method of FIG. 4 and shown in FIG. 4 and 5, A is α (3T) = 0 and B is α (3T)
= 0.09T and C are the characteristics when α (3T) = 0.19T, respectively. 4 and 5, the horizontal axis β (%)
Is a parameter standardized in relation to the asymmetry of the reproduced waveform, and is a parameter different from the fine adjustment amount β (mT).

The 3T land jitter is required to have a β (%) of 35 or less in a range of 0 to 8%. Also, 3
The T-pit deviation is required to have β (%) of 40 or less in a range of 0 to 8%. According to FIG.
When α (3T) = 0.19T (C), the 3T land jitter is the best, but according to FIG. 5, when α (3T) = 0.19T (C), the allowable amount of 3T pit deviation is 40. Will be exceeded. Also, when α (3T) = 0.09T (B) is 3T
The pit deviation falls within the allowable range, but the 3T land jitter is considerably inferior to (C) when α (3T) = 0.19T.

As described above, in the conventional apparatus, as the recording speed magnification increases, the time resolution of the fine adjustment amounts α (nT) and β (mT) relatively increases, so that the jitter, the deviation, the error rate, etc. are optimized. It was not possible to set the values of α (nT) and β (mT) so that Increasing the oscillation frequency of the crystal oscillator increases the time resolution, so α (nT), β (mT)
Can be set to an optimum value, but the apparatus becomes expensive.

The present invention solves the above-mentioned problem in the prior art, and when the recording speed magnification is high, the fine adjustment amount α
Without increasing the time resolution of (nT) and β (mT),
It is an object of the present invention to provide an optical disk recording apparatus capable of adjusting recording signal quality such as deviation and error rate to an optimum state.

[0009]

According to the present invention, a beam power of a recording laser beam is set to a top power at which a pit is formed in a section in which a pit is formed, and after a pit is formed, the beam power is maintained until a next pit is formed. In an optical disc recording apparatus in which a pit is not formed in a section where a land is formed and the recording laser beam is irradiated on the recording surface of the optical disc to form pits and lands by a mark length recording method, In the case where recording is performed at a speed higher than the speed, control for changing the end timing of the top power from the original end timing of the pit to be formed according to the length of the pit to be formed, or according to the control and the land length to be formed. Controlling the start timing of the top power from the original end timing of the land to be formed, In a part of the top power, a portion is formed that temporarily increases the top power value with an increase power width smaller than the difference between the top power value and the bottom power value (in this specification, this increase is used). The part which is referred to as a “top power additional pulse” is controlled to vary the length of the top power additional pulse according to the pit length to be formed, or the bottom power value is added to a part of the bottom power. Is formed temporarily with a reduced power width smaller than the difference between the top power value and the bottom power value (this reduced portion is referred to as a “bottom power off pulse” in this specification), Control is performed to vary the length of the bottom power-off pulse in accordance with the length of the land to be formed, or both controls are performed.

When the top power additional pulse is lengthened, 1
As the energy input to form one pit increases, the trailing edge of the pit moves rearward,
When the top power additional pulse is shortened, the energy input to form one pit decreases, and the trailing edge of the pit moves forward to be formed. In this case, if the increased power width (the amount of increase with respect to the top power value) of the top power added pulse is smaller than the difference between the top power value and the bottom power value, the energy value of the top power added pulse per time resolution will be (I.e., the energy value per time resolution of the fine adjustment amount α (nT)). Therefore, even if the time resolution of the top power added pulse is the same as the time resolution of α (nT), adjusting the length of the top power added pulse is more energy than adjusting the length of α (nT). The amount can be finely adjusted, and the position of the trailing edge of the pit can be finely adjusted. Therefore, the position of the trailing edge of the pit can be accurately formed by roughly adjusting the fine adjustment amount α (nT) of the overall length of the top power and further adjusting the length of the top power additional pulse. it can.

On the other hand, if the bottom power-off pulse is lengthened, the energy applied to the section forming one land decreases, so that the trailing edge of the land (= the leading edge of the pit)
Are formed by moving backward, and when the bottom power-off pulse is shortened, the energy input to the section forming one land decreases, so that the trailing edge of the land moves forward and is formed. In this case, if the decreasing power width of the bottom power off pulse (the amount of decrease with respect to the bottom power value) is smaller than the difference between the top power value and the bottom power value, the energy value of the bottom power off pulse per time resolution will be Energy value of bottom power (ie, energy value per time resolution of β (mT) of fine adjustment amount)
Smaller than. Therefore, even if the time resolution of the bottom power off pulse and the time resolution of β (mT) are the same, it is better to adjust the length of the bottom power off pulse to obtain β (mT).
The amount of energy input can be finely adjusted as compared with the length T), and the position of the land trailing edge can be finely adjusted. Therefore, by roughly adjusting the fine adjustment amount β (mT) of the overall length of the bottom power and further adjusting the length of the bottom power off pulse, it is possible to accurately form the rear edge position of the land. it can.

By adjusting the length of the top power additional pulse or the bottom power off pulse, or the length of both, the recording signal quality such as jitter, deviation, and error rate can be improved. The present invention also includes control for varying the increased power width of the top power additional pulse in accordance with the pit length to be formed or control for varying the reduced power width of the bottom power off pulse in accordance with the formed land length. Although this does not hamper the operation, if the increased power width of the top power added pulse is common to each pit length, or the reduced power width of the bottom power off pulse is common to each land length, the top power added pulse or the bottom power Only the time control of the power-off pulse is required, and the variable control of the increase power width or the decrease power width is not required, so that the control becomes easy.

The top power added pulse can be formed at an arbitrary point in the section of the top power. However, if the top power addition pulse is formed at the beginning of the top power, the timing control pulse is generated in comparison with the case where the top power addition pulse is formed in the middle of the top power. Is easy, and the power at the beginning of the top power irradiation is large compared to the case where it is formed at the end of the top power, so that the pit front edge position can be formed accurately and the pit width increases at the pit rear edge. Can be suppressed. Further, the bottom power off pulse can be formed at an arbitrary position in the section of the bottom power. However, if the bottom power off pulse is formed at the beginning of the start of the bottom power, the timing control is easier than when it is formed at an intermediate position of the bottom power. In addition, since the power immediately after the end of the top power is sharply reduced as compared with the case where the power is formed at the end of the bottom power, the position of the trailing edge of the pit can be accurately formed. Further, the top power additional pulse is not limited to being formed for all pit lengths, but may be formed for only some pit lengths. The bottom power off pulse is not limited to being formed for all land lengths. Alternatively, it can be formed only on a part of the land length.

[0014]

Embodiments of the present invention will be described below. FIG. 6 shows a system configuration of an optical disk recording / reproducing apparatus 1 to which the present invention is applied. Input device 28
In, the recording speed magnification is set by an operator's operation or the like. In response to a command from the system controller 19, the disk servo circuit 16 controls the spindle motor 12 to maintain a constant linear velocity at the set recording speed magnification (1.2 m / x at 1 × speed).
s to 1.4 m / s, at 2x speed, 2x at 1x speed, at 4x speed, 4x at 1x speed, at 6x speed, 6x at 1x speed, ...
)) To control the rotation. This linear velocity constant control is performed by CD-W
In the case of the O standard, the pre-group wobble (Wobbl
Since e) is specified to be 22.05 kHz, a wobble is detected from the output signal of the optical head 13 (it can be detected from the remaining tracking error signal), and this is at a predetermined frequency (22 at 1 × speed). .05kH
z 44.1kHz at 2x speed, 88.2kHz at 4x speed
,...) Are realized by PLL control of the spindle motor 12.

The focus servo and tracking servo circuit 18 controls the focus and tracking of the laser beam 11 emitted from the semiconductor laser in the optical head 13 according to a command from the system controller 19. The tracking control is performed by detecting a pre-groove formed on the optical disc 10. The feed servo circuit 17 drives the feed motor 20 in accordance with a command from the system controller 19 to move the optical head 13 in the radial direction of the optical disk 10.

An input signal to be recorded on the optical disk 10 (CD-WO disk) is input directly to the recording signal forming circuit 22 when it is a digital signal at a speed corresponding to the recording speed magnification, and when it is an analog signal such as an audio signal. Is A / D
The signal is input to the recording signal forming circuit 22 via the converter 24.
The recording signal forming circuit 22 interleaves the input data to give an error check code, and also gives the TOC information and subcode information generated by the TOC and subcode generating circuit 23, and performs EFM modulation to perform CDM A series of serial data is formed at a transfer rate according to the format and the recording speed magnification, and is output as a recording signal.

The recording signal is modulated by a recording strategy selected by the recording signal correction circuit 26 via the drive interface 15 in accordance with the type of disk used (dye material, manufacturer, etc.), linear velocity, recording speed magnification, and the like. In response, it is input to the laser generation circuit 25. The laser generation circuit 25 drives the semiconductor laser in the optical head 13 in accordance with the recording signal, irradiates the recording surface of the optical disc 10 with laser light, and forms pits for recording. At this time, the laser power is instructed to a value corresponding to the recording speed magnification and, if necessary, the linear velocity, and the ALPC (Automatic Laser Power Control) is used.
rol) The power is controlled with high precision by this circuit. Thus, the format, transfer speed and linear speed (1.2 to 1.4 m /
Data is recorded in s).

The optical disk 10 recorded as described above
When the reproduction is performed by irradiating the reproduction laser beam (lower power than the recording laser beam) to the reproduction data, the read data is transmitted to the signal reproduction processing circuit 30.
And demodulated as a digital signal,
The signal is converted into an analog signal by the A converter 31 and output.

FIG. 1 shows a control block of recording control by the system controller 19 shown in FIG. The recording speed magnification setting means 28 corresponds to the input device 28 in FIG. 6, and sets the recording speed magnification (× 1, × 2, × 4, × 6,...) By the operation of the operator. The disc type and linear velocity determining means 32
The disc type and the linear velocity of the optical disc 10 set in the apparatus are determined. The disc type is
For example, a disk I previously recorded on the optical disk 10
The discrimination can be made by using information indicating the disc type in D. For the linear velocity, for example, the recording time (63-minute type, 74-minute type, and other intermediate types) recorded in the ATIP signal at the lead-in portion of the disk is read, and the corresponding linear velocity is determined (63 minutes). It can be calculated from the encoder output of the spindle motor or 1.4 m / s for the type and 1.2 m / s for the 74 minute type.

The recording strategy storage means 34 stores the optimal recording strategy (time modulation amount, recording power, etc.) according to the combination of the disc type, the linear velocity and the recording speed magnification. The recording strategy selection means 36 reads out a corresponding recording strategy from the recording strategy storage means 34 according to the information of the inputted disc type, linear velocity, and recording speed magnification. The control means 38 controls the recording signal correction circuit 26 in accordance with the read recording strategy to modulate the length of the pit forming portion or blank forming portion of the recording signal. Further, it controls the laser generation circuit 25 to control the laser power. Further, the disk servo circuit 16 is controlled to control the rotation of the spindle motor 12 at a speed corresponding to the commanded recording speed magnification.

The control means 38 shown in FIG.
The specific contents of the control of the irradiation time of the recording laser light and the control of the recording power according to the present invention will be described. FIG. 7 shows an example of a temporal change of the recording power of the recording laser beam by the control means 38.
(A). FIG. 7B shows the plan shapes of the pits and lands formed on the optical disk at this time. The control means 38 adjusts the beam power of the recording laser beam to the top power P at which a pit is formed in a section where the pit is formed.
t, and the bottom power Pb at which no pits are formed in a section where a land is formed after a pit is formed until the next pit is formed. Further, a top power additional pulse 40 is formed at the beginning of the top power Pt, and a bottom power off pulse 42 is formed at the beginning of the bottom power Pb.
To form In this specification, the section of the top power includes the section of the top power additional pulse 40,
The section of the bottom power includes the section of the bottom power off pulse 42.

The increased power width ΔPt of the top power added pulse 40 is set to a value smaller than the difference Pt−Pb between the top power Pt and the bottom power Pb, and is constant (for example, 1.5 mW) regardless of the pit length to be formed. ) Or a value that changes according to the length of the pit to be formed. The reduced power width ΔPb of the bottom power off pulse 42 is the difference P between the top power Pt and the bottom power Pb.
It is set to a value smaller than t-Pb, and is set to a constant value (for example, 0 mW; a finite value is also possible) regardless of the land length to be formed.

The control means 38 determines the length of the pit length nT (n = 1, 2,..., 1)
1) and the land length mT before that (m = 1, 2,...)
, 11), the basic recording strategy (n−K) T + α (nT) −β (mT), where K: constant α (nT): correction amount for each pit length, for example, α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧ α (8T) (α (3T)> α
(8T)) β (mT): correction amount for each land length immediately before, for example, β (3T) ≧ β (4T) ≧ β (5T) ≧... ≧ β (8T) (β (3T)> β
(8T)).

The control means 38 controls the pulse width ΔTt (nT) of the top power additional pulse 40 according to the pit length nT to be formed, and controls the pulse width ΔTb (mT) of the bottom power off pulse 42. Is controlled in accordance with the land length mT to be formed. Additional pulse 40,
The pulse widths ΔTt (nT) and ΔTb (mT) of the off pulse 42 are
When 6 × speed recording is performed using the basic strategy, each pit length nT and each land length mT are adjusted so that the jitter, deviation, error rate, etc. of each pit length nT and each land length mT are optimized. Set forth in
Note that the pulse width ΔT of the additional pulse 40 and the off pulse 42
Only one of the variable control of t (nT) and ΔTb (mT) may be performed.

Top power value Pt, bottom power value Pb
And the parameters ΔTt (nT), ΔTb (mT), ΔP of the additional pulse 40 and the off pulse 42
t and ΔPb are determined for each disc type and recording speed magnification, and for each linear velocity as needed.
During recording, the basic strategy and the parameters of the additional pulse 40 and the off-pulse 42 are read out at the time of recording according to the type of disc to be used, the recording speed magnification, and if necessary, the linear velocity. Then, the control signal 38 controls the recording signal correction circuit 26 and the laser generation circuit 25 of FIG. That is, the recording signal correction circuit 26 is controlled according to the time information of the basic strategy, and the parameters ΔTt (nT), ΔTb (mT), ΔPt of the top power value Pt, the bottom power value Pb, and the additional pulse 40 and the off pulse 42 are controlled. ΔPb
The laser generation circuit 25 is controlled according to. Then, a recording laser beam is emitted from the optical head 13 and irradiated on the recording surface of the optical disk 10 to form pits and lands of 3T to 11T, and information is recorded. In addition,
The time resolutions of the time adjustment amounts α (nT), β (mT), ΔTt (nT), and ΔTb (mT) are common. For example, when a 276 MHz clock is created by performing 33.8 × 4 × (98/96) × 2 circuit processing using a 33.8 MHz crystal oscillator, the time resolution is 3.6 ns, and the 6 × speed recording is performed. The case corresponds to a length of 0.09T.

Here, an example of actual recording by the optical disk recording apparatus of the present invention will be described. The same basic strategy (n-0.2) T + α (nT) as in the measurement was applied to the same phthalocyanine-based disk used in the measurement in FIGS.
Using -0.09T, the top power Pt and the bottom power Pb were set to the same conditions as in the measurement, and a top power additional pulse 40 and a bottom power off pulse 42 were added to perform 6-times speed recording. Top Hour Additional Pulse 40
The pulse width ΔTt (nT) was set as follows according to the pit length nT to be formed.

ΔTt (3T) = 1.5T ΔTt (4T) to ΔTt (11T) = 1.0T Further, the increased power width ΔP of the top power additional pulse 40
t was set to 1.5 mW common to each pit length. Further, the pulse width ΔTb (mT) of the bottom power off pulse 42 is 1.
0T, and the reduced power width ΔPb is Pb (therefore, the absolute power value of the bottom power off pulse 42 is 0 m
W).

FIGS. 8 and 9 show the results of measuring the 3T land jitter and 3T pit deviation by reproducing the recorded disk, and show the results of measurement of the 3T land jitter and 3T pit deviation (overlapped with the measurement results of FIGS. 4 and 5). 8 and 9, the characteristics A, B, and C are the characteristics A, B, and C in FIGS. 4 and 5, and the characteristic D is the characteristic obtained by recording according to the present invention. According to the characteristic D according to the recording of the present invention, the 3T land jitter is significantly improved over the characteristic B in a state where the 3T pit deviation is within an allowable range.

The present invention is particularly effective when performing high-speed recording at a speed of 6 times or more. However, when performing high-speed recording slower than that (recording at a speed magnification higher than the standard speed and lower than 6 times speed). Can also be applied.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing an embodiment of the present invention, showing the contents of recording control by a system controller of FIG. 6;

FIG. 2 is a waveform diagram showing a temporal change in laser power of a conventional recording laser.

FIG. 3 is a waveform diagram showing a temporal change in laser power of a conventional recording laser to which a top power additional pulse is added.

FIG. 4 is a graph showing a 3D image recorded using the recording laser shown in FIG. 3;
It is a T land jitter characteristic diagram.

FIG. 5 is a graph showing a 3D image recorded using the recording laser shown in FIG. 3;
It is a T pit deviation characteristic diagram.

FIG. 6 is a system configuration block diagram showing an embodiment of an optical disk recording / reproducing apparatus to which the present invention is applied.

FIG. 7 is a waveform diagram showing an example of a temporal change in laser power of a recording laser according to the present invention, and a plan view showing pit and land shapes formed by the recording laser.

FIG. 8 is a graph showing a 3D image recorded using the recording laser shown in FIG. 7;
It is a T land jitter characteristic diagram.

FIG. 9 shows a 3D image recorded by using the recording laser shown in FIG. 7;
It is a T pit deviation characteristic diagram.

[Explanation of symbols]

 10 optical disk 38 control means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B ^7/ 00-7/013 G11B 7/125

Claims (5)

(57) [Claims] 1. A beam power of a recording laser beam is set to a top power at which a pit is formed in a section in which a pit is formed, and a pit is formed in a section in which a land is formed after a pit is formed until a next pit is formed. In the optical disk recording apparatus that sets the pits and lands by the mark length recording method by irradiating the recording laser light to the recording surface of the optical disk by setting the bottom power at which no is formed, the recording is performed at a speed higher than the standard speed. When performing the control, the end timing of the top power is changed from the original end timing of the pit to be formed in accordance with the length of the pit to be formed, or the start timing of the top power is changed in accordance with the control and the land length to be formed. Control to vary from the original end timing of the land to be formed is performed, and a part of the top power is controlled. A top power additional pulse that temporarily increases the top power value with an increase power width smaller than the difference between the top power value and the bottom power value is formed, and the length of the top power additional pulse is formed to according to the pit length becomes comprises a control means for controlling to vary, control to vary the length of the top power additional pulse
Energy value of top power added pulse per time resolution
To change the end timing of the top power.
Than the energy value of the top power per your time resolution
An optical disc recording apparatus, wherein the control for changing the length of the top power additional pulse is more finely adjustable than the control for changing the end timing of the top power. 2. The beam power of a recording laser beam is set to the top power at which a pit is formed in a section in which a pit is formed, and the pit is formed in a section in which a land is formed after a pit is formed until the next pit is formed. In the optical disk recording apparatus that sets the pits and lands by the mark length recording method by irradiating the recording laser light to the recording surface of the optical disk by setting the bottom power at which no is formed, the recording is performed at a speed higher than the standard speed. When performing the control, the start timing of the top power is changed from the original end timing of the land to be formed according to the length of the land to be formed, or the end timing of the top power is changed according to the control and the length of the pit to be formed. Control is performed to vary from the original end timing of the pits to be formed, and a part of the bottom power is controlled. A bottom power off pulse for temporarily reducing the bottom power value with a reduced power width smaller than the difference between the top power value and the bottom power value is formed, and the length of the bottom power off pulse is Control means for performing a control to vary the length according to the land length to be formed; and
Energy value of bottom power off pulse per time resolution
Is controlled by changing the start timing of the top power.
Than the energy value of the bottom power per your time resolution
An optical disc recording apparatus, wherein the control for changing the length of the bottom power-off pulse is smaller than that for changing the start timing of the top power, so that the amount of energy input can be finely adjusted. 3. A beam power of a recording laser beam is set to a top power at which a pit is formed in a section in which a pit is formed, and a pit is formed in a section in which a land is formed after a pit is formed until the next pit is formed. In the optical disk recording apparatus that sets the pits and lands by the mark length recording method by irradiating the recording laser light to the recording surface of the optical disk by setting the bottom power at which no is formed, the recording is performed at a speed higher than the standard speed. When performing, control to change the end timing of the top power from the original end timing of the pit to be formed according to the length of the pit to be formed, and the start timing of the top power to be formed according to the land length to be formed. While performing control to fluctuate from the original end timing of the land, the top power is applied to a part of the top power. A pit length that forms a top power additional pulse that temporarily increases the power value with an increase power width smaller than the difference between the top power value and the bottom power value, and determines the length of the top power additional pulse And performing a control to fluctuate the bottom power value in a part of the bottom power value and temporarily reducing the bottom power value with a reduced power width smaller than the difference between the top power value and the bottom power value. Forming a power-off pulse and controlling the length of the bottom power-off pulse in accordance with the length of the land to be formed; and
Energy value of top power added pulse per time resolution
To change the end timing of the top power.
Than the energy value of the top power per your time resolution
And the length of the bottom power off pulse is reduced.
Bottom power off power per time resolution of variable control
Lus energy value, the top power start timing
Of bottom power per time resolution of control
Energy value is smaller than, the control to vary the length of the top power additional pulse, so that the amount of energy input can be finely adjusted than the control to vary the end timing of the top power, and, An optical disc recording apparatus in which the control for varying the length of the bottom power off pulse allows the amount of energy input to be more finely adjusted than the control for varying the start timing of the top power. 4. The optical disk recording apparatus according to claim 1, wherein the top power additional pulse is formed with a power value common to each pit length at the beginning of the top power. 5. The optical disk recording apparatus according to claim 2, wherein the bottom power off pulse is formed with a power value common to each bottom length at the beginning of the bottom power.