JPH06162519A - Optical pickup device - Google Patents

Abstract

PURPOSE:To always quickly complete adjustments even if various conditions are changed and to follow up changes of external factors in the case of injecting inspection signals in a servo loop and making adjustments of the characteristics of the servo loop by the response from the injection. CONSTITUTION:By a gain adjustment control circuit 13, whether an optical disk device is in a recording operation or a reproducing operation is judged; if in a reproducing operation, an instruction is given to a circuit 7 for generating inspection signals so as to make the amplitude of the inspection signals larger; and simultaneously, the average number of times for the results of a gain measurement that is performed in a gain setting circuit 12 is reduced. In the gain setting circuit 12, the gain of the servo loop is set in accordance with the average result. Thus, the amplitude of the inspection signals is increased at the time of reproduction where the control precision is not required, and the gain adjustment is performed at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc device for reading information from an optical disc by optical means.

[0002]

2. Description of the Related Art In recent years, compact disc players,
Optical disk devices such as magneto-optical disks have become widespread. In these optical disc devices, the focus servo that controls the focal position of the optical pickup so that the optical disc is always focused, and the position of the optical spot (information reading / writing point) of the optical pickup that always follows the information track are set. The tracking servo to control is indispensable. Since these servos usually generate error signals based on the reflected light from the optical disk, changes in external factors such as differences in optical disk reflectance and fluctuations in the amount of light emitted by the semiconductor laser in the optical pickup. The servo may become unstable due to the
A method has been proposed in which the current state of the servo loop is detected and the constant of the loop filter is changed. For example, the method disclosed in JP-A-1-89034 is one of them.

FIG. 4 shows a block diagram of a conventional optical disk device. The focus or tracking servo in this conventional example is realized by a servo loop including a detection system 41 that detects an error signal, a phase compensation unit 42 that performs transfer compensation, a gain adjustment unit 43, and a drive system 45 that drives a lens. When adjusting the characteristic of the servo loop (gain adjustment here), the microcomputer 40 injects the inspection signal 40 into the gain adjusting unit 43, and inputs the response signal 47 to this. The microcomputer 40 obtains the gain of the servo loop from the response signal 47, judges whether this gain is a predetermined value, and if it is not a predetermined value, adjusts the gain control signal 35 that brings the gain close to the predetermined value. It is sent to the gain control unit 44 in the unit 43.
The gain control unit 44 changes the gain of the servo loop according to the gain control signal 35.

[0004]

As described above, in the optical disk device of the type in which the inspection signal is injected from outside the servo loop to measure the characteristics of the servo loop and the characteristics of the servo loop are adjusted, it takes time to adjust the characteristics. It had a problem that it took a lot of time. This is because it is difficult to obtain a correct measurement result by one measurement for the following reasons.
This is for performing averaging processing of the measurement results of several times. That is, firstly, since the inspection signal is originally a disturbance signal for the servo loop, the amplitude is made small, and secondly, the servo loop operates so as to reduce the error signal including the inspection signal. Therefore, the amplitude of the response signal of the inspection signal becomes small. In particular, the recording type optical disk device has a stricter requirement for the control result (for example, the amount of deviation between the position of the track and the light spot in the tracking servo) than that of the reproducing type optical disk device. Therefore, it is necessary to reduce the amplitude of the inspection signal, and it is necessary to increase the average number of times to obtain a correct measurement result, which causes a problem that it takes time.

In view of the above problems, it is an object of the present invention to realize an optical disk device capable of quickly inspecting the current state of the servo loop and shortening the time required for adjusting the servo loop.

[0006]

According to the present invention, a test signal generating means for generating a test signal, a test signal injecting means for injecting a test signal generated by the test signal generating means into a servo loop, and an input signal are supplied. The state detection unit that detects the current state of the servo loop by detecting the reaction of the servo loop and the average of the detection results output by the state detection unit are averaged, and the result is taken as the current servo loop state, and this and the target state. And adjusting means for changing the characteristics of the servo loop so that the current state approaches the target state.
It is characterized by comprising an amplitude adjusting means for changing the inspection signal large during the period (2) and small during the second period.

[0007]

According to the present invention, by providing the above means, the amplitude of the inspection signal at the time of recording and reproducing is changed, or
By changing the amplitude of the inspection signal according to the recording state of the data on the optical disc, it is possible to shorten the time required from the measurement to the completion of adjustment.

[0008]

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

FIG. 1 is a block diagram of an optical disk device according to a first embodiment of the present invention. Reference numeral 1 is an optical disk, 2 is a semiconductor laser (not shown) that emits laser light, a lens 3 that narrows down the laser emitted by the semiconductor laser, a tracking actuator 4 that moves the lens 3 in the horizontal direction with respect to the optical disk 1, and an optical disk. An optical head having a tracking error signal generation circuit 5 which receives the reflected light from the optical disc 1, and outputs a tracking error signal based on the reflected light.
6 is a tracking control circuit for inputting a tracking error signal and driving the tracking actuator 4 so that the value of this signal is small, 7 is an inspection signal generating circuit for generating an inspection signal, and 8 is for injecting the inspection signal into the servo loop. Adder 9 is a drawing point 10 and 11 before and after the adder 8.
A loop gain measuring circuit for extracting the component corresponding to the inspection signal from the signal in FIG.
The gain setting circuit for inputting the measurement result of (1), averaging, and comparing with the target gain, and changing the gain of the tracking control circuit 6 according to the comparison result, 13 indicates whether the optical disk device is in the recording operation or the reproducing operation. A gain adjustment control circuit that makes a determination and instructs the inspection signal generation circuit 7 to increase the amplitude of the inspection signal if the reproduction operation is in progress, and at the same time instructs the gain setting circuit 12 to reduce the number of averaging processes. Is.

The operation of the tracking servo of the first embodiment will be described below. The tracking servo is performed by a servo loop including a tracking error signal generation circuit 5, a tracking control circuit 6 and a tracking actuator 4. That is, the tracking error signal generation circuit 5 determines whether the light spot is displaced on the inner side or the outer side with respect to the track on which the information is recorded or the information recording track based on the reflected light from the optical disc 1. The tracking error signal shown is output. A known method of generating the tracking error signal includes a three-beam method and a push-pull method which are already known, but the description thereof is omitted because it is not related to the gist of the present invention. The tracking error signal generated by the tracking error generation circuit 5 enters the tracking control circuit 6, and in the tracking control circuit 6, when the light spot is shifted to the inner circumference side, the lens 3 is shifted to the outer circumference side and the outer circumference side. When it is present, a drive signal for moving it to the inner peripheral side is supplied to the tracking actuator 4. The tracking actuator 4 moves the lens 3 in the horizontal direction with respect to the recording surface according to the drive signal output from the tracking control circuit 6.

Now, in order to measure the current gain of such a servo loop, the gain adjustment control circuit 13 controls the inspection signal generation circuit 7 and the gain setting circuit 12. First, the gain adjustment control circuit 13 checks whether or not recording is currently performed on the optical disc 1, and when recording is being performed, “small amplitude of inspection signal” and “average number of times” of gain measurement results are set. In order to do so, the inspection signal generating circuit 7 and the gain setting circuit 12 are instructed. The inspection signal generation circuit 7 receives the instruction of "small amplitude of inspection signal", and outputs an inspection signal having a frequency of a target gain intersection point and a small amplitude. The inspection signal output from the inspection signal generation circuit 7 is injected into the tracking servo loop by the adder 8. The loop gain measuring circuit 9 inputs signals from the leading and trailing points of the adder 8 and obtains a ratio of these,
Get the open loop gain of the servo loop. That is, if the signal at the pull-out point 10 is A, the signal at the pull-out point 11 is B, and all the transfer functions of the tracking control circuit 6, the tracking actuator 4, and the tracking error signal generation circuit 5 are H (S), B / A
= H (S), and the open loop characteristic can be obtained. Now, the gain data thus obtained enters the gain setting circuit 12. In the gain setting circuit 12,
First, the gain data is averaged. Since the signal of the target gain intersection frequency is used as the inspection signal, if the gain data output from the gain measuring circuit 9 is 0 dB, it can be said that the servo loop is in the optimum state. Therefore, the gain setting circuit 12 sets the gain of the tracking control circuit 6 so as to decrease the gain when the gain data is larger than 0 dB and increase the gain when the gain data is smaller than 0 dB. The tracking control circuit 6 changes the gain according to the instruction from the gain setting circuit 12 and drives the tracking actuator 4.

The above is the operation of the tracking servo during recording, but the following operation is performed during reproduction. The gain adjustment control circuit 13 instructs the inspection signal generation circuit 7 to "large amplitude of inspection signal" and the gain setting circuit 12 to "small average number". The inspection signal generation circuit 7 receives the instruction of "large amplitude" and generates an inspection signal having a large amplitude. The gain setting circuit 12 receives the instruction of "small number of averaging", reduces the number of gain data to be averaged, and sets the gain promptly. The tracking control circuit 6 changes the gain according to the instruction of the gain setting circuit 12 and drives the tracking actuator 4.

As described above, according to the present embodiment, the gain adjustment control circuit 13 changes the magnitude of the inspection signal according to whether or not the recording operation is being performed, and controls the average number of measurement results accordingly. Therefore, optimum measurement conditions can be created at the time of recording and at the time of reproduction, and the gain can always be adjusted quickly and accurately.

Next, the second embodiment will be described.
FIG. 2 is a block diagram of the optical disk device of the second embodiment. Reference numeral 21 is a magneto-optical type optical disk on which data including at least address information is recorded in advance, and 22 is a semiconductor laser 23 that emits light for irradiating the optical disk 21.
And a lens 2 that narrows down the light emitted by the semiconductor laser 23.
4. A tracking actuator 25 for moving the lens 24 in the horizontal direction with respect to the optical disc 21, and a light receiving circuit 26 for receiving the light reflected by the optical disc 21 and generating and outputting a tracking error signal and an information signal such as an address therefrom. An optical head 27 inputs a tracking error signal and supplies a drive signal to the tracking actuator 25 so as to reduce this value. A tracking control circuit 28 moves the optical spot irradiated on the optical disk 21 by one track. A kick pulse generation circuit for supplying a kick pulse to the tracking actuator 25, and 29 is a tracking actuator 25
Switch circuit for switching the signal to be supplied to 210, an inspection signal generation circuit for generating an inspection signal, 211 an adder for injecting the inspection signal into the servo loop, and 212 for the gain of the servo loop from the signals at the extraction points 213 and 214. Gain measuring circuit 215 for measuring and outputting gain data
Is a gain setting circuit for inputting gain data and setting the gain of the tracking control circuit 27 based on the gain data, 21
6 is a gain adjustment control circuit that controls the inspection signal generation circuit 210 and the gain setting circuit 215 depending on whether or not a recording operation is performed, and 217 is an address demodulation circuit that reproduces address information from the information signal output from the light receiving circuit 26. 21
Reference numeral 8 is a system controller for controlling the movement of the entire optical disk apparatus, 219 is a laser drive circuit for outputting an optical drive signal for driving the semiconductor laser 23, and 220 is the optical disk 2.
A magnetic head 221 for changing the magnetic field applied to 1 is a magnetic drive circuit for driving the magnetic head 220, and 222 is a data compression circuit for compressing digital data such as audio data inputted from the outside and supplying it to the magnetic drive circuit 221. is there.

The operation of the optical disk device of the second embodiment will be described below. At the time of reproduction, the system controller 218 supplies the drive signal from the tracking control circuit 27 to the switch circuit 29 to the tracking actuator 25 so that the laser drive circuit 219 emits the semiconductor laser 23 at the reproduction intensity. Instruct each. The semiconductor laser 23 is a laser drive circuit 219.
Light is emitted in accordance with the optical drive signal from the optical disk 21 and is applied to the optical disk 21 via the lens 24. Data such as address information is recorded on the optical disk 21, for example, by the method disclosed in Japanese Patent Laid-Open No. 1-224929. Since the difference in the method of recording the address information does not relate to the gist of the present invention, the description is omitted. The irradiated light is reflected by the optical disk 21 and enters the light receiving circuit 26. The light receiving circuit 26 generates a tracking error signal from the input light and outputs the data recorded on the optical disc 21 as an information signal. Now, the tracking error signal output from the light receiving circuit 26 is added with the inspection signal generated by the inspection signal generation circuit 210 by the adder 211, and enters the tracking control circuit 27. The tracking control circuit 27 knows the deviation direction of the light spot from the input tracking error signal. If the deviation is in the inner circumference side, the tracking actuator is moved to the outer circumference direction. Drive 25.
Since the switch circuit 29 is tilted to the tracking control circuit 27 side, the drive signal is the tracking actuator 2
5, the tracking actuator 25 moves the lens 24 in the instructed direction. Gain measurement circuit 212, gain setting circuit 215, gain adjustment control circuit 2
16 performs the same operations as the gain measuring circuit 9, the gain setting circuit 12, and the gain adjustment control circuit 13 at the time of reproduction of the first embodiment, respectively, and the gain of the servo loop of the tracking servo is always kept appropriate.

At the time of recording, the amplitude of the inspection signal cannot be increased as shown in the first embodiment, and the adjustment takes time. On the other hand, in the present embodiment, the data to be recorded is compressed to reduce the data amount, and the data is recorded intermittently so that the servo loop characteristics can be adjusted in a short time. When recording, the data to be recorded is supplied to the data compression circuit 222. In the data compression circuit 222, the input data is divided into a predetermined length, for example, every 5 seconds.
Data is compressed to about 1/5. 5 seconds worth of data
Since the data is compressed to one-half, the time required for recording can be shortened to 1 second. When the compression is completed, the system controller 218 is notified of the completion of the compression, and the compressed data is supplied to the magnetic drive circuit 221. System controller 21
In 8, the laser drive circuit 21 receives the notification of the end of compression.
9 is instructed to drive the semiconductor laser 23 at the recording intensity. The laser drive circuit 219 receives an instruction to emit light at the recording intensity and drives the semiconductor laser 23 at the recording intensity. At the same time, the magnetic drive circuit 221 drives the magnetic head 220 based on the data received from the data compression circuit 222 to record the data on the optical disc 21. When the recording of the compressed data is completed in 1 second, the system controller 218 obtains the address at the end of the recording from the address demodulation circuit 217, stores the address, restores the laser intensity for reproduction, and sends it to the gain adjustment control circuit 216. On the other hand, it is instructed to perform gain adjustment based on the amplitude of the inspection signal during reproduction and the average number of times. The gain adjustment control circuit 216 instructs the inspection signal generation circuit 210 to increase the amplitude of the inspection signal and the gain setting circuit 215 to reduce the average count, and adjusts the gain within a short time of at least 4 seconds. To do. During this time, the system controller 218
Using the kick pulse generation circuit 28 and the switch circuit 29, preparation is made so that data can be continuously recorded from the recording end position stored previously when the next compression end notification is input. That is, when the difference between the address indicating the recording end position and the address where the light spot is scanning becomes large, a kick pulse is applied to the tracking actuator 2.
Then, the process is performed such that the light spot is supplied to No. 5 and the light spot is moved to the previous or previous track. When the next compression end notification is input, the system controller 218 monitors the address output by the address demodulation circuit 217, and sets the laser drive circuit 219 to the recording intensity when the light spot scans the recording end position outside the front, The gain adjustment control circuit 216 is instructed to perform gain adjustment with the recording inspection signal amplitude and the average number of times.

As described above, in the second embodiment, the data compression circuit 222 is provided, the time required for recording data is shortened, and the remaining time is used to adjust the gain by increasing the amplitude of the inspection signal. As a result, the time required for gain adjustment can be shortened even when recording data. Since this increases the number of adjustments per unit time, it becomes possible to more closely follow changes in external factors.

The third embodiment will be described below with reference to the drawings. FIG. 3 is a block diagram of the optical disk device of the third embodiment. 2 to 4 and 6 to 11 are the same as those described in the first embodiment. Reference numeral 31 is a magneto-optical recording type optical disc having a pit portion in which data is unevenly recorded on the inner peripheral portion and a groove portion having a guide groove for recording information is arranged on the outer portion thereof, and 32 is an area scanned by a light spot. Recording state judgment circuit for judging whether or not is a pit part, 3
3 is a gain for controlling the inspection signal generation circuit 7 so as to increase the amplitude of the inspection signal if it is a pit portion and decrease the amplitude of the inspection signal if it is not a pit portion in accordance with the determination result of the recording state determination circuit 32. An adjustment control circuit, 34 is a gain setting circuit that sets the gain of the tracking control circuit 6 based on the gain data output from the gain measurement circuit 9, and 35 is a tracking error signal and total reflection indicating the amount of total reflection light from the optical disc 31. It is a light receiving circuit that outputs a light amount signal.

The operation of the third embodiment will be described below. The optical disc 31 used in this embodiment has a recommended laser intensity for recording, an address of a boundary between a pit portion and a groove portion, audio data, image data, computer data, and the like. This is something that the manufacturer of the optical disc records in advance when the disc is manufactured.
Information such as recommended laser intensity that is essential when using an optical disc and information that increases the commercial value of the optical disc, such as computer data, is the shape of unevenness that cannot be erased by a magneto-optical disc device. It is recorded in. When adjusting the gain of the servo loop in the optical disk device of this embodiment using such an optical disk, the following processing is performed.

First, the gain adjustment control circuit 33 inputs the determination result output from the recording state determination circuit 32 and determines whether or not the portion currently scanned by the light spot is a pit portion. The recording state determination circuit 32 determines the recording method using the total reflection light amount signal output from the light receiving circuit 35. That is, the total reflection light amount signal in the state where both the focus servo and the tracking servo are applied has a high frequency component because the reflected light is modulated by the unevenness at the pit portion, whereas the groove portion has no unevenness. The total reflected light amount signal has almost only a DC component. By detecting this difference, it is determined whether or not it is a pit portion. Now, the gain adjustment control circuit 33 sends an instruction to the inspection signal generation circuit 7 so that the amplitude of the inspection signal is small if it is not the pit portion and is large if it is the pit portion. This is based on the idea of injecting the minimum required inspection signal. That is, in the pit portion, the reflected light is modulated by the concavities and convexities formed on the optical disc, and components other than the actual servo error enter each error signal in the tracking error signal created by the reflected light, which becomes noise and gain measurement is performed. Adversely affect. To prevent the adverse effect of this noise, increase the amplitude of the inspection signal in the pit area,
I am trying to improve the signal-to-noise ratio. The gain measuring circuit 9 obtains the gain of the servo loop from the signals before and after the adder 8 and outputs the result to the gain setting circuit 34 as gain data. The gain setting circuit 34 inputs gain data, determines the set gain under the same conditions (average number of times, integration period, etc.) regardless of whether or not it is a pit portion, and sets the gain of the tracking control circuit 6.

As described above, in the third embodiment, it is determined whether or not the area currently scanned by the light spot is the pit portion, and the amplitude of the inspection signal is changed according to the result of the determination, so that the optical disc is read. It is possible to eliminate the influence of noise caused by the difference in the data recording method, and it is possible to adjust the gain quickly and accurately even with an optical disc in which data is recorded by a plurality of recording methods. .

In the first, second and third embodiments, the tracking servo has been described as an example.
It is clear that the same effect can be obtained in focus servo and the like.

Further, in the first and second embodiments, the average number of gain measurement results is reduced when the amplitude of the inspection signal is increased, but the average number need not necessarily be reduced. This is because it is clear that the larger the inspection signal, the more accurate the gain setting can be made each time when the same average number of times is performed, and the time required until the adjustment is finally completed (the target gain is reached). Is smaller than when the inspection signal is small.

Further, in the first, second and third embodiments, when the gain is measured, the open loop gain is obtained from the amplitude of the signal before and after the adder, but the inspection signal is injected into the servo loop. As long as the response of the servo loop to the inspection signal is detected and measured, for example, Japanese Patent Application Laid-Open No. 1-89034 and Japanese Patent Application Laid-Open No. 61-11, which are shown in the related art, are disclosed.
Any measuring method such as the method disclosed in Japanese Patent No. 82108 may be used. Further, in addition to the gain adjustment, for example, a method of measuring and adjusting the frequency characteristic may be used.

In the second embodiment, the case where the data for 5 seconds before compression is compressed to 1/5, the data is recorded in 1 second, and the gain adjustment is completed within 4 seconds has been described. The gain adjustment does not have to be particularly completed for each recording, and the gain may be measured during several recordings and averaged. In this case as well, it goes without saying that the average frequency can be reduced by increasing the magnitude of the inspection signal.

In the second embodiment, the case where the measurement adjustment processing is performed by reducing the amplitude of the inspection signal during the recording operation has been described. However, when the adjustment during the reproduction operation can obtain a sufficient adjustment result. In addition, during the recording operation, the amplitude of the inspection signal to be injected may be set to 0, or the measurement adjustment process may not be performed.

In the third embodiment, the inspection signal amplitude is changed depending on the difference between the pit portion and the groove portion. However, the inspection signal amplitude may be changed depending on whether or not data is recorded. For example, in an optical disc in which data is recorded by a difference in reflectance, such as a phase change type optical disc, a portion where data is recorded is the same as a pit being present, and data is not recorded. Since the amount of noise is larger than that of the portion, it is possible to increase the amplitude of the inspection signal at this time, and the effect is great.

Further, in the third embodiment, the recording state detection circuit 32 monitors the total reflected light amount to determine whether or not the high frequency component is included as a method of determining the pit portion and the groove portion. For example, when the address of the boundary between the pit portion and the groove portion is recorded in advance on the optical disc, it is determined whether or not it is the pit portion by comparing the current address with the address of the boundary. It does not matter which method is used for the determination.

[0029]

As described above, according to the first aspect of the invention, when the inspection signal is injected into the servo loop of the servo to measure and adjust the characteristics of the servo loop, the inspection is performed at the time of reproduction rather than at the time of recording. By increasing the amplitude of the signal, the average number of measurement results can be reduced, and the characteristics can be measured and adjusted more quickly. In particular, the optical discs currently in practical use often have a read-only area in which recording conditions are recorded in a specific area even if it is a recordable optical disk, and the optical disk device first reproduces that portion. Since the operation shifts from the recording operation to the recording operation, speeding up the adjustment during reproduction as in the present invention is very effective in speeding up the operation (start-up operation) of the entire apparatus immediately after the power is turned on or the optical disk is replaced. is there.

According to the second aspect of the invention, when data is recorded, the data to be recorded is compressed and the recording operation and the reproducing operation (loop characteristic measurement adjustment processing) are performed intermittently. It is possible to adjust the loop characteristics at high speed even during recording. For this reason, even during recording when particularly severe control results are required for the focus servo and tracking servo, it is possible to follow changes in external factors with the same fineness as during reproduction.
Great effect.

According to the third aspect of the invention, there is provided recording state judging means for judging the recording state of the data on the optical disc.
By increasing the amplitude of the inspection signal when the noise component at the time of characteristic measurement becomes large, it becomes possible to follow the change in the amount of noise due to the difference in the recording state of the optical disc.
In the optical discs actually used, the data pre-recorded by the disc manufacturer is in the form of pits, and the disc user often has a guide groove in the area where the data is added below, and this difference can be absorbed. Is very effective in practice.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of an optical disc device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an optical disc device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional optical disc device.

[Explanation of symbols]

 1, 21, 31 Optical disc 7, 210 Inspection signal generation circuit 8, 211 Adder 9, 212 Gain measurement circuit 12, 34, 215 Gain setting circuit 13, 33, 216 Gain adjustment control circuit 32 Recording state determination circuit 218 System controller 222 Data compression circuit

Claims (4)

[Claims] 1. A light emitting means for emitting light for irradiating an optical disc, a condensing means for condensing the light emitted by the light emitting means, and a focus position moving means for moving the condensing means in a direction substantially perpendicular to the optical disc. A focus error detecting means for detecting a focus position of the light condensed by the light collecting means and a positional deviation of the optical disc in the vertical direction and outputting it as a focus error signal; and inputting the focus error signal, the focus position A focus position control means for controlling the focus position moving means so as to eliminate the positional deviation between the optical disk and the optical disk; a tracking direction moving means for moving the focusing means in a substantially radial direction; and a spiral or concentric circle on the optical disk. Tracking error detecting means for detecting a deviation between the formed track and the radial position of the focal point position and outputting it as a tracking error signal; A tracking error signal is inputted, a tracking control means for controlling the tracking direction moving means so as to eliminate the positional deviation between the focus position and the track, an inspection signal generating means for generating an inspection signal, and the inspection signal, A focus servo loop including the focus error error detecting means, the focus position moving means, and the focus position controlling means, or a tracking servo loop including the tracking error detecting means, a tracking direction moving means, and a tracking controlling means, or either one of them. Inspection signal injecting means for injecting into the servo loop, state detecting means for detecting the current state of the servo loop by detecting the reaction of the servo loop to the inspection signal injected in the servo loop, and the detection result output by the state detecting means, Compare the target states and change the current state to the target state Adjusting means for changing the characteristics of the servo loop, and characteristic adjusting control means for controlling the inspection signal generating means so as to change the inspection signal large in the first period and small in the second period. An optical disk device comprising: 2. A recording state determination means for determining the recording state of the optical disc from the light reflected by the optical disc, wherein the characteristic control means changes the amplitude of the inspection signal based on the determination result output by the recording state determination means. The optical disk device according to claim 1, wherein: 3. The method according to claim 1, wherein the first period is a period for reproducing data recorded on the optical disc, and the second period is a period for recording data on the optical disc. Optical disk device. 4. A data compression means for compressing data to be recorded on an optical disc to reduce the data amount, a data recording means for recording the compressed data on the optical disc, and a data recording operation by the data recording means at the time of data recording. 4. The optical disk device according to claim 3, further comprising a system controller that alternately performs adjustment of a servo loop by a reproducing operation.