JP2004185675A - Optical disk device, its status measuring method, and status measuring position setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device which can control the power for recording to an optical disk correctly and at a high speed, its status measuring method and a status measuring position setting method with respect to the optical disk device which can record a signal on the disk at a plurality of recording speeds, its status measuring method, and the status measuring position setting method. <P>SOLUTION: In the status measuring method of the optical disk device (1) which records a signal while rotating a disk (2) at a prescribed rotation speed set in advance from a plurality of rotation speeds, and varying the recording speeds, when the rotation speed of the disk (2) is reduced at a prescribed signal status measuring position, a status of a signal at a reduced rotation speed is estimates based on already measured results at a same recording speed of other rotation speed, and recording power at a reduced rotation speed is controlled based on the guessed signal state. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device, a method of measuring a state thereof, and a method of setting a state measurement position, and more particularly to an optical disk device capable of recording a signal on a disk at a plurality of recording speeds, a method of measuring a state of the optical disk, and a method of setting a state measurement position.
[0002]
[Prior art]
For a compact disk-recordable (CD-R) or a compact disk-rewritable (CD-RW) disk, the optimum recording power of the laser differs depending on the manufacturer or the like. For this reason, in an optical disk device for recording information on a compact disk-recordable (CD-R) or compact disk-rewriteable (CD-RW) disk, when the disk is mounted and a recording instruction is issued, an OPC (optimum power control) is performed. ) The processing is executed. The OPC process is a process for measuring the optimum recording laser power, and is performed using a PCA (power calibration area) set on the inner circumference of the optical disc.
[0003]
Here, OPC will be described.
[0004]
In the OPC, first, a predetermined signal is recorded on the PCA while changing the recording power of the laser at a predetermined recording speed in 15 steps. Next, the signal recorded on the PCA is reproduced, and 15 types of β values are obtained from the peak value and the bottom value of the reproduced signal.
[0005]
FIG. 12 is a diagram for explaining a method of measuring the β value.
[0006]
The β value is determined based on the following equation (1), where A1 is the peak value of S1 and A2 is the bottom value of the signal in FIG.
[0007]
β = (A1 + A2) / (A1-A2) (1)
FIG. 13 is a diagram showing the relationship between the recording power and the β value.
[0008]
As shown in FIG. 13, the β value changes quadratically, and the recording power pw0 at which the β value becomes the smallest is the optimum recording power.
[0009]
Therefore, the recording power at which the minimum β value is obtained from the 15 types of β values obtained based on equation (1) is set as the optimum recording power at the predetermined recording speed.
[0010]
By performing the above operation at each recording speed, the optimum recording power at each recording speed is obtained. The obtained optimum recording power for each recording speed is set in a register of the microcomputer and used at the time of signal recording (for example, see Patent Document 1).
[0011]
[Patent Document 1]
JP-A-2002-298356 (paragraph numbers [0019] to [0012], FIG. 2)
[0012]
[Problems to be solved by the invention]
In the conventional optical disk device, the recording power is set based on the optimum recording power set by the OPC, and the radial position of the optical disk is not considered. Therefore, there is a problem that the recording power cannot be set accurately.
[0013]
The present invention has been made in view of the above points, and an object of the present invention is to provide an optical disk apparatus capable of controlling the recording power on an optical disk at high speed and accurately, a method of measuring the state of the optical disk, and a method of setting a state measurement position.
[0014]
[Means for Solving the Problems]
The present invention relates to a method for measuring a state of an optical disk device (1) for rotating a disk (2) at a predetermined rotational speed among a plurality of preset rotational speeds and recording a signal while varying a recording speed. When the rotation speed of the disk (2) is reduced at the signal state measurement position, the state of the signal at the reduced rotation speed is estimated and estimated based on the results of the other rotation speeds already measured at the same recording speed. The recording power at the reduced rotation speed is controlled based on the signal state.
[0015]
According to the present invention, when the rotation speed of the disk (2) is reduced at a predetermined signal state measurement position, the state of the signal at the reduced rotation speed is obtained by measuring the signal state at the same recording speed of another rotation speed. By controlling the recording power at the reduced rotation speed based on the estimated signal state, the optimum recording can be performed without measuring the signal state when the rotation speed of the disk (2) is reduced. Recording can be performed with power.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing an embodiment of an optical disk apparatus according to the present invention.
[0017]
The optical disk device 1 according to the present embodiment is a drive capable of recording and / or reproducing a CD-R, a CD-RW, and the like, and is configured to record a signal in a constant angle velocity (CAV) system. The outermost circumference is set so that the maximum recording speed such as 48 ×, 42 ×, or 36 × can be obtained at the outermost circumference.
[0018]
The configuration mainly includes a turntable 11, a spindle motor 12, an optical pickup 13, a thread motor 14, an interface 15, a memory 16, a memory controller 17, an encoder 18, a laser controller 19, a read amplifier 20, a decoder 21, and a servo controller 22. , A driver 23, a microcomputer 24, and a WPC position table 25.
[0019]
The optical disk 2 is mounted on the turntable 11. The turntable 11 is rotated by the spindle motor 12 to rotate the optical disc 2 in, for example, the direction of arrow A. The spindle motor 12 rotates according to a drive signal from a driver 23.
[0020]
The optical pickup 13 is disposed so as to face the optical disc 2, and irradiates the optical disc 2 by converging the light beam L by the objective lens 31. The optical pickup 13 incorporates an actuator (not shown) for swinging the objective lens 31 in the direction of arrow B to perform tracking control and swinging the objective lens 31 in the direction of arrow C to perform focus control. . The actuator is driven by a drive signal from a driver 23, and swings the objective lens 31 in directions of arrows B and C to perform tracking and focus control.
[0021]
The driver 23 supplies drive signals to the spindle motor 12, the sled motor 14, and an actuator (not shown) for performing the tracking and focus control according to a control signal from the servo controller 22. The thread motor 14 is a motor for moving the optical pickup 13 in the radial direction of the optical disk 2, that is, in the direction of arrow B.
[0022]
The servo controller 22 generates a control signal for controlling the actuator and the sled motor 14 for performing tracking and focus control based on the tracking error signal and the focus error signal supplied from the read amplifier 20, and supplies the control signal to the driver 23. I do. Further, the servo controller 22 controls the rotation of the spindle motor 12 and controls the actuator and the sled motor 14 based on an instruction from the microcomputer 24. For example, the rotation speed of the spindle motor 12 is controlled in accordance with the recording speed specified by the microcomputer 24. Further, based on an instruction from the microcomputer 24, the focus and tracking actuators are turned off, and the thread motor 13 is driven to execute a seek operation.
[0023]
The optical pickup 13 has a built-in photodetector (not shown). The photodetector detects a focus error signal, a tracking error signal, and a recording signal, and supplies them to the read amplifier 20. The read amplifier 20 amplifies the focus error signal and the tracking error signal and supplies the amplified signal to the servo controller 22. The read amplifier 20 amplifies the recording signal and supplies the amplified signal to the decoder 21 and the microcomputer 24.
[0024]
The decoder 21 decodes a recording signal from the read amplifier 20. The data decoded by the decoder 21 is temporarily stored in the memory 16 by the memory controller 17. The data stored in the memory 16 is supplied to the host computer via the interface 15 that interfaces with the host computer. In addition, the memory 16 is configured by a random access memory (RAM) and is used as a buffer memory. The memory controller 17 controls communication between the interface 15, the memory 16, the encoder 18, and the decoder 21.
[0025]
The recording data from the host computer is temporarily stored in the memory 16 via the interface 15 and then supplied to the encoder 18. The encoder 18 encodes the recording data and generates a recording signal. The recording signal encoded by the encoder 18 is supplied to a laser controller 19. The laser controller 19 drives a laser diode (not shown) built in the optical pickup 13.
[0026]
The laser diode emits light based on a drive signal from the laser controller 19. The light beam emitted from the laser diode is converged by the objective lens 31 and irradiated on the optical disc 2.
[0027]
During recording, the laser controller 19 causes a laser diode incorporated in the optical pickup 13 to emit light based on a recording signal from the encoder 18. For example, the laser diode increases the intensity of the light beam when the recording signal from the laser controller 19 is at a high level, and decreases the intensity of the light beam when the recording signal is at a low level. The pits are formed on the optical disc 2 when the intensity of light from the laser diode is high. By the above operation, pits are formed on the optical disc 2 according to the recording signal. During reproduction, the laser controller 19 irradiates the optical disc 2 with light having an intensity at which no pits are formed.
[0028]
At this time, the laser controller 19 controls the intensity of light emitted from the laser diode based on an instruction from the microcomputer 24. When the microcomputer 24 instructs to increase the light intensity from the microcomputer 24, the laser controller 19 increases the level of the drive signal supplied to the laser diode, thereby increasing the intensity of the light emitted from the laser diode. When the microcomputer 24 instructs the microcomputer 24 to decrease the light intensity, the laser controller 19 reduces the level of the drive signal supplied to the laser diode, thereby decreasing the intensity of the light emitted from the laser diode.
[0029]
The WPC position table 25 stores the position where WPC is performed for each recording speed.
[0030]
FIG. 2 shows a data configuration diagram of the WPC position table 25.
[0031]
As shown in FIG. 2, the WPC position table 25 indicates the WPC position in absolute time (min). In this embodiment, irrespective of the recording speed, the absolute time is "0", "5'34" 22 ","12'52"18","22'24" 01 ","34'49"18", WPC is set to be executed at the positions of "51'02" 27 "and"72'15"16.
[0032]
3 and 4 are diagrams illustrating a change in recording speed with respect to the absolute time on the optical disc 2, and FIG. 5 is a diagram illustrating a change in recording speed with respect to the radius on the optical disc 2.
[0033]
4 and 5, "●" indicates the WPC position when the WPC position is performed at the absolute time shown in FIG.
[0034]
The signal state is measured at the position shown in FIG. At this time, when the absolute time is “00′00” 00, the recording speed at 48 × speed is 20.9 ×. At the absolute time "05'34" 22 ", the recording speed at 48-times speed becomes 23.9 times, and at 42-times speed, which is a recording speed reduced by one step from 48-times speed, the recording speed is 20.9 times. It becomes. This is the same as the recording speed in the absolute time "00'00" 00 "of 48 times speed.
[0035]
At the absolute time "12'52" 18 ", the recording speed at 48-times speed becomes 27.3 times and the recording speed at 42-times speed becomes 23.9 times. At this time, the recording speed at 42 × is the same as the recording speed at the absolute time “05′34 ″ 22” at 48 ×.
[0036]
Further, at the absolute time "22'24" 01 ", the recording speed at 48-times speed becomes 31.2 times, and the recording speed at 42-times speed becomes 27.3 times. At this time, the recording speed of 42 × speed is the same as the recording speed of the 48 × speed in the absolute time “12′52 ″ 18”.
[0037]
At the absolute time "34'49" 18 ", the recording speed at 48-times speed becomes 35.6 times, and the recording speed at 42-times speed becomes 31.2 times. The 42 × speed recording speed is the same as the 48 × speed absolute time “22′24 ″ 01”.
[0038]
Further, at the absolute time "51'02" 27 ", the recording speed at 48-times speed becomes 40.7 times, and the recording speed at 42-times speed becomes 35.6 times. At this time, the recording speed at 42 × speed is the same as the recording speed at the absolute time “34′49 ″ 18” at 48 × speed.
[0039]
At the absolute time “72′15 ″ 16”, the recording speed at 48 × is 46.5 × and the recording speed at 42 × is 40.7 ×. At this time, the recording speed at 42 × speed is the same as the recording speed at the absolute time “51′02 ″ 27” at 48 × speed.
[0040]
Therefore, the absolute times "00'00" 00 ","05'34"22","12'52" 18 ","22'24"01","34'49" 18 ", and"51'02". 27 "and"72'15"16" are WPC positions, and signal measurement is performed. For example, as a result of measuring a signal state at an absolute time "05'34" 22 ", the recording speed is reduced from 48x speed to 42x speed. When reduced, the recording speed is 20.9 times. At this time, if the recording has been performed at 48 × speed up to the absolute time “05′34 ″ 22”, the WPC has already been performed at 20.9 × at the absolute time “00′00” 00 ”. Therefore, it is assumed that the WPC result at the absolute time "05'34" 22 at the 42-times speed is substantially the same as the WPC measurement result at the absolute time "00'00" 00 "at the 48-times speed. Therefore, when the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “05′34 ″ 22”, the WPC result at the absolute time “00′00 ″ 00” at the 48 × speed is substituted to newly add There is no need to perform WPC.
[0041]
Similarly, when the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “12′52 ″ 18”, a new WPC result at the 48 × speed absolute time “05′34 ″ 22” is used instead. No WPC is required. When the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “22′24 ″ 01”, a new WPC result at the 48 × speed absolute time “12′52 ″ 18” is substituted. WPC becomes unnecessary. Further, when the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “34′49 ″ 18”, a new WPC result at the 48 × speed absolute time “22′24 ″ 01” is used instead. WPC becomes unnecessary.
Similarly, when the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “51′02 ″ 27”, a new WPC result at the 48 × absolute time “34′49 ″ 18” is substituted. No WPC is required. Further, when the recording speed is reduced from 48 × speed to 42 × speed at the absolute time “72′15 ″ 16”, a new WPC result at the 48 × absolute time “51′02 ″ 27” is substituted. WPC becomes unnecessary.
[0042]
That is, as shown in FIG. 4 and FIG. 5, when the recording speed at the 48x speed is reduced to 42x at the 48x WPC position, the recording speed at the 42x speed is reduced to the recording speed at the 48x WPC position. The WPC position is set to match.
[0043]
For the sake of simplicity, the description has been made with respect to the 48 × speed and the 42 × speed as an example. However, by setting the same at a recording speed of 36 × or less, when the recording speed is reduced by WPC, a new speed is set. It is not necessary to perform a proper WPC.
[0044]
Next, the recording operation of the microcomputer 24 for realizing the above operation will be described in detail.
[0045]
FIG. 6 shows a flowchart of the microcomputer 24 during a recording operation.
[0046]
When the optical disk 2 is inserted in step S1-1 and recording of a signal on the inserted optical disk 2 is instructed in step S1-2, the microcomputer 24 executes OPC (optimum power control) in step S1-3. . The OPC is performed using a PCA (power calibration area) provided on the inner peripheral side of the optical disc 2.
[0047]
In the OPC, as in the related art, a predetermined signal is recorded on the PCA at a predetermined recording speed while changing the recording power in 15 steps. Next, a signal recorded on the PCA is generated, and a β value at each recording power is obtained from the peak value and the bottom value according to the equation (1). Next, in the OPC process, the recording power at which the minimum β value is obtained from the 15 levels of β values obtained is set as an optimum recording power in a register built in the microcomputer 24. The above processing is performed at each recording speed, the optimum recording power at each recording speed is obtained, and the optimum recording power is set in a register built in the microcomputer 24. Thus, the OPC process ends.
[0048]
Next, the microcomputer 24 starts a recording operation in step S1-4. At this time, the microcomputer 24 performs the recording operation at the optimum recording power set corresponding to the recording speed among the optimum recording powers obtained by the OPC in step S1-3. When the WPC position is set in advance in the WPC position table 25 in step S1-5, the microcomputer 24 performs a WPC process in step S1-6. At this time, the microcomputer 24 detects the absolute time included in the wobble signal extracted from the wobble formed in advance on the optical disc 2 and compares the detected absolute time with the absolute time set in the WPC position table 25 to thereby determine the WPC position. Is determined.
[0049]
The WPC process is a process of obtaining a β value at a preset position and obtaining an optimum recording power. In the WPC process, for example, since the characteristics of the β value are different between the inner circumference and the outer circumference of the disk 2, optimal recording cannot be performed on the outer circumference of the disk 2 only by the optimum recording power obtained by the OPC. This is a process performed to correct the optimum recording power at the set position.
[0050]
The microcomputer 24 repeats steps S1-4 to S1-6 until there is a recording end instruction in step S1-7, and if there is a recording end instruction in step S1-7, stops the recording operation in step S1-8. The processing ends.
[0051]
Next, the WPC process will be described in detail.
[0052]
FIG. 7 shows a flowchart of the microcomputer 24 at the time of the WPC process.
[0053]
When the WPC process is started, the microcomputer 24 first stops the recording operation in step S2-1. Next, the microcomputer 24 seeks the recording signal before a predetermined time in step S2-2.
[0054]
FIG. 8 is a diagram illustrating the operation of the WPC process.
[0055]
In FIG. 8, the WPC process is started at time t1, the recording operation is stopped, and at time t2 after the operation waiting time Δt1 has elapsed from time t1, seek is performed at time t3 before time Δt3, and the recorded signal S1 is read. At this time, the recorded signal S1 is a signal recorded at a time t0 before the time Δt0 from the time t1 at which the recording operation is stopped. As a result, the signal S1 after the elapse of the predetermined time T = (Δt0 + Δt1 + Δt2) can be read. By setting the predetermined time T to about 4 seconds, it is possible to handle almost all optical disks. Note that the predetermined time T is not limited to 4 seconds, and the time required for the characteristics, that is, the β value to stabilize, and the time during which the β value can be acquired can be minimized. Set to.
[0056]
Further, the predetermined time T may be switched according to the manufacturer of the optical disk or the like.
[0057]
The microcomputer 24 acquires the peak value A1 and the bottom value A2 of the signal S1 recorded before the predetermined time T in step S2-3, and obtains the β value. By obtaining the β value from the signal S1 before the predetermined time T, the characteristic, that is, the characteristic, that is, the β value is obtained after the β value is stabilized, so that the accurate β value can be obtained. Therefore, an appropriate recording power can be accurately obtained.
[0058]
At this time, the WPC process can be performed in a short time by setting the recording time Δt0, the operation waiting time Δt1, and the seek time Δt2 to the minimum required.
[0059]
Returning to FIG. 7, the description will be continued.
Next, in step S2-4, the microcomputer 24 determines whether or not the β value is within an allowable range of the recording power control, that is, within a limit range.
[0060]
If the β value is within the limit range in step S2-4, the microcomputer 24 determines in step S2-5 whether the β value is within the allowable range.
[0061]
If the β value is within the allowable range in step S2-5, the microcomputer 24 restarts the recording operation in step S2-6 without changing the recording power. If the β value is out of the allowable range in step S2-5, the microcomputer 24 changes the recording power so that the β value becomes smaller in step S2-7, and then resumes the recording operation in step S2-6. .
[0062]
If the value of β is out of the limit range in step S2-4, the microcomputer 24 cannot respond to the change in the recording power, and thus executes the recording speed reduction process in step S2-8. The recording speed reduction process is a process of reducing the recording speed by one step. For example, if the recording speed is 24 ×, the control is performed such that the recording speed is set to 20 ×, and the process returns to step S2-2, and the recording speed is reduced. Then, the optimum recording power is determined again.
[0063]
Here, the recording speed reduction processing in step S2-8 will be described in detail.
[0064]
FIG. 9 shows a processing flowchart of the recording speed reduction processing.
[0065]
The microcomputer 24 reduces the recording speed by one step in step S3-1. For example, if the speed is 48 ×, the speed is 42 ×, and if the speed is 42 ×, the speed is 36 ×.
[0066]
Next, in step S3-2, the microcomputer 24 acquires the optimum recording power set at the WPC position before the WPC position at the recording speed before the reduction. For example, when the speed is reduced from 48 × speed to 42 × speed at the absolute time “05′34 ″ 22”, the optimum recording power obtained as a result of the WPC at the 48 × speed and the absolute time “00′00 ″ 00” is reduced. get.
[0067]
Next, the microcomputer 24 sets the acquired optimum recording power to the optimum recording power at the current position at the reduced recording speed. For example, when the speed is reduced from 48 × speed to 42 × speed at the absolute time “05′34 ″ 22”, the optimum recording power obtained as a result of the WPC at the 48 × speed and the absolute time “00′00” 00 ”is reduced. The optimum recording power at 42 × speed and the absolute time “05′34 ″ 22” is set.
[0068]
Next, the microcomputer 24 restarts the recording operation with the optimum recording power acquired in step S3-4. For example, from the 42 × speed and the absolute time “05′34 ″ 22”, the recording operation is restarted with the optimum recording power obtained as a result of the WPC at the 48 × speed and the absolute time “00′00” 00 ”.
[0069]
As described above, WPC at the time of reducing the recording speed can be omitted. Therefore, it is possible to quickly shift to the recording operation. Further, as a result of measuring the state of the signal recorded at the same recording speed at the time of the transition, recording can be performed with the obtained recording power, so that accurate recording can be performed.
[0070]
In this embodiment, in the WPC process, the signal recorded before the predetermined time T is reproduced to obtain the β value after the β value is stabilized, and control such as the recording power is performed. The β value may be obtained by reproducing the latest signal later.
[0071]
FIG. 10 shows a flowchart of a modification of the WPC process of the microcomputer 24. In the figure, the same reference numerals are given to the same processing parts as in FIG. 6, and the description thereof will be omitted.
[0072]
In this embodiment, after stopping the recording operation in step S2-1, the microcomputer 24 starts a timer in step S4-1 and waits for a predetermined time to elapse in step S4-2. After a predetermined time has elapsed in step S4-2, the microcomputer 24 seeks the latest recording signal in step S4-3, reads the peak value and bottom value of the latest recording signal, and calculates the β value in step S2-3. Measure.
[0073]
FIG. 11 is an operation explanatory diagram of a modified example of the WPC process.
[0074]
After the recording operation is completed at the position p0, the position p2 of the latest signal S11 is sought at the position p1 after the elapse of the time Δt11, the latest signal S11 is read, and the β value is measured from the peak value and the bottom value.
[0075]
At this time, by setting the predetermined time Δt11 in consideration of the seek time Δt12 from the position p1 to the position p2, a signal can be read in a minimum necessary time.
[0076]
In the present embodiment, an optical disk device for recording a signal on a compact disk-recordable (CD-R) or compact disk-rewritable (CD-RW) disk has been described. However, a DVD-RAM, MO (magneto It can be provided to other recordable optical disk devices such as optical.
[0077]
Further, the characteristic measuring method according to the present embodiment can be applied without being limited to a recording method such as a CLV method, a CAV method, and a zone CLV method.
[0078]
【The invention's effect】
As described above, according to the present invention, when the rotation speed of the disk is reduced at the predetermined signal state measurement position, the state of the signal at the reduced rotation speed is already measured at the same recording speed of the other rotation speeds. By controlling the recording power at the reduced rotation speed based on the estimated signal condition based on the result, the optimum recording power can be obtained without measuring the signal condition when the disk rotation speed is reduced. It has features such that recording can be performed, and therefore, signal recording can be performed at high speed and accurately.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an optical disk apparatus according to an embodiment of the present invention.
FIG. 2 shows a data configuration diagram of a WPC position table 25.
FIG. 3 is a diagram showing a change in a recording speed with respect to an absolute time on an optical disc 2;
FIG. 4 is a diagram showing a change in recording speed with respect to an absolute time on the optical disc 2;
FIG. 5 is a diagram showing a change in recording speed with respect to a radius on the optical disc 2;
FIG. 6 is a flowchart at the time of a recording operation of the microcomputer 24;
FIG. 7 is a flowchart at the time of WPC processing of the microcomputer 24;
FIG. 8 is a diagram illustrating the operation of the WPC process.
FIG. 9 is a processing flowchart of a recording speed reduction processing.
FIG. 10 is a flowchart of a modified example of the WPC process of the microcomputer 24. .
FIG. 11 is a diagram illustrating an operation of a modification of the WPC process.
FIG. 12 is a diagram for explaining the measurement operation of β.
FIG. 13 is a diagram showing a relationship between recording power and β value.
[Explanation of symbols]
1 optical disk device, 2 optical disk
11 turntable, 12 spindle motor, 13 optical pickup
14 thread motors, 15 interfaces, 16 memories
17 memory controller, 18 encoder, 19 laser controller
20 read amplifier, 21 decoder, 22 servo controller
23 drivers, 24 microcomputers, 25 WPC position table
31 Objective lens

Claims (8)

In an optical disk device that rotates a disk at a predetermined rotation speed among a plurality of rotation speeds set in advance and records a signal while changing a recording speed,
A signal state measuring means for stopping the recording operation at a preset state measuring position and measuring the state of the signal,
When the rotation speed of the disk is reduced based on the measurement result of the signal state measurement unit, the state of the signal at the reduced rotation speed is determined based on the result of the measurement at the same recording speed of the other rotation speeds. Signal state estimating means for estimating,
An optical disk device comprising: a recording power control unit that controls recording power at the reduced rotation speed based on the signal state estimated by the signal state estimation unit. 2. The optical disk device according to claim 1, wherein the signal state estimating unit uses a result measured at a higher rotation speed. In the signal state measurement unit, recording is performed at a signal state measurement position for measuring a signal state when recording the disk at a predetermined rotation speed at a recording speed when the disk is reduced from a predetermined rotation speed. 3. The optical disk device according to claim 1, wherein the position is set in advance. In a method for measuring a state of an optical disk device for rotating a disk at a predetermined rotation speed among a plurality of rotation speeds set in advance and recording a signal while changing a recording speed,
When the rotation speed of the disk is reduced based on the measurement result at a predetermined signal state measurement position, the state of the signal at the reduced rotation speed is determined based on the result of the measurement at the same recording speed of the other rotation speeds. Guess,
A method for measuring a state of an optical disk device, comprising controlling recording power at the reduced rotation speed based on an estimated signal state. 5. The method according to claim 4, wherein a result measured at a higher rotation speed is used. A signal state measurement position for measuring a signal state when recording the disk at a predetermined rotation speed is set in advance to a position where recording is performed at a recording speed when the disk is reduced from a predetermined rotation speed. The method for measuring the state of an optical disk device according to claim 4 or 5, wherein: A method for setting a state measurement position of an optical disk device that rotates a disk at a predetermined rotation speed among a plurality of rotation speeds set in advance and records a signal while changing a recording speed,
A state measurement position at a higher rotational speed of the disk, which is set to a position at which the recording speed is the same as a recording speed when the disk is reduced to a lower rotational speed at the state measurement position; Position setting method. A step of setting a state measurement position at a higher recording speed at a higher rotation speed of the disk;
When the rotational speed of the disk is reduced at the state measurement position, a position at which the recording speed is the same as the recording speed at the reduced rotational speed is set as the state measurement position. Item 7. The method for setting a state measurement position of an optical disk according to Item 7.

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