JP2002288848A - Optical disk device and adjusting method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an optical disk device to show stable servo characteristics with simple constitution in the recording and reproduction of a DVD-RAM or the like in which a recording area and a non-recording area are mixed. SOLUTION: This optical disk device 100 is provided with a data presence-or- absence deciding circuit 160 which decides the presence or absence of recorded data on a position on an optical disk 101 to which servo gain is initially adjusted, a gain finely-adjusting part 162 consisting of a gain correction table 161 for adjusting the initially adjusted servo gain based on the result of the decision made by the data presence-or-absence deciding circuit 160 and a register 151 which stores the result of the adjustment of the servo gain so that the servo gain corrected by the gain finely-adjusting part 162 may be set when a recording or reproduction is made to the optical disk 101. By this, it is possible to make an adjustment so that average servo gains in both the recording area and non-recording area of the optical disk (DVD-RAM) 101, which are each different in reflection of a laser light, may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk device, and more particularly to an optical disk device capable of reproducing and recording data and a method of adjusting the same.

[0002]

2. Description of the Related Art Conventionally, an optical disk apparatus uses a focus servo that exactly matches a focus position of an objective lens of an optical head to a recording surface of an optical disk, and a tracking servo that causes a laser beam applied to the optical disk to follow a track. Is required.

The focus servo and the tracking servo calculate an output signal of a multi-segmented photodetector for detecting the reflected light from the optical disk to generate a focus error signal and a tracking error signal. This is realized by servo-controlling each object based on the results.

By the way, when considering mass production of an optical disk device, the characteristics of a servo loop of a focus servo and a tracking servo (hereinafter, referred to as “servo characteristics”) are as follows.
The designed characteristics generally differ from device to device by an amount corresponding to the characteristic variation of each produced pickup, and also change with time.

[0005] Further, considering that reproduction from a plurality of optical discs is performed by the same optical disc apparatus, even if the optical disc specifications are the same, the reflectivity of each disc,
The focus error signal, tracking error signal, RF signal, and the like change for each disk due to factors such as differences in pit shape and environmental temperature.

Therefore, in the optical disk device, the variation in the actual servo characteristics caused by these factors is absorbed by adjusting the gain of the servo equalizer. In other words, the gain adjustment result is stored in a register when the optical disk device is manufactured, and the adjustment result stored in the register is read out during normal reproduction and set in the servo equalizer, thereby realizing the actual servo of the optical disk device. The characteristics can be made closer to the designed characteristics.

[0007]

Incidentally, in such a conventional optical disk device, there are the following problems in an optical disk device for recording / reproducing a recordable / reproducible optical disk, for example, a DVD-RAM or the like.

That is, in a DVD-RAM or the like in which a data recording area / non-recording area is mixed, the reflectivity of laser light differs between the recording area and the non-recording area, and the servo characteristics are affected. That is, such a DVD-RA
In an optical disk device that performs recording and reproduction of M and the like, a servo loop gain of a focus servo and a tracking servo (hereinafter, referred to as “servo gain”) at the time of manufacturing the device.
Is adjusted in the recording area and the servo gain is set to be optimum in this recording area, the servo gain becomes too high in the non-recording area, and a product with an unstable servo system is manufactured. On the other hand, when the servo gain is adjusted to the optimum value in the non-recording area, the servo gain in the recording area is too low, and the servo system is also unstable.

Therefore, in order to avoid the fluctuation of the servo gain due to the reflectance difference between the recording area and the non-recording area, the change in the servo gain is sequentially detected by monitoring the amplitude value of the full addition signal during recording and reproduction. An optical disk device or the like equipped with an AGC circuit that always optimizes the servo gain has been put to practical use.

However, in an optical disk device in which gain is adjusted by an AGC circuit, there is a problem of occurrence of an adjustment error due to an offset shift of the AGC circuit. In some devices, an offset circuit is further added in order to reduce the influence of the offset shift. However, the additional circuit is complicated and expensive, causing a problem in cost. If such a gain adjustment function is not provided, of course, the resonance characteristics and the like of the actuator of the optical head are strictly controlled, and the servo system is controlled so that this amplitude variation falls within the range of the servo gain margin and phase margin. It is necessary to configure the parts with extremely high precision, which causes problems in cost and part production.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. For example, when recording or reproducing an optical disk having a mixed recording area / non-recording area, stable servo characteristics can be exhibited with a simple configuration. The present invention provides an optical disk device and a method for adjusting the same.

[0012]

To achieve the above object, an optical disk apparatus according to the present invention comprises an optical head, servo means for applying servo to an objective lens of the optical head, and a radius on the optical disk. Initial adjustment means for initially adjusting the servo gain of the servo means in a state where servo is applied to the objective lens of the optical head by the servo means at an arbitrary position in the direction, and recording data at the arbitrary position on the optical disk. Data presence / absence determination means for determining the presence / absence of, gain correction means for correcting the servo gain initially adjusted by the initial adjustment means based on the determination result by the data presence / absence determination means, and gain corrected by the gain correction means. This correction is performed so that the servo gain is set for the servo means during recording or reproduction of the optical disk. Characterized by comprising a servo gain storing means for the adjustment result to memory retention of that.

Further, in the optical disk device according to the present invention, the optical disk is a recordable / reproducible disk having a higher reflectance of light in a non-recording area than in a recording area, and the gain correction means includes: When the data presence / absence determination unit determines that there is recording data at the arbitrary position, the gain is corrected so as to increase the gain, and when it is determined that there is no recording data, the gain is corrected so as to decrease the gain. And

[0014] Further, the optical disk device according to the present invention comprises:
The data presence / absence determining means determines presence / absence of recording data on the optical disk based on a detection result of a full addition signal, an error correction signal, or a synchronization signal generated based on a signal obtained from the optical disk through the optical head. It is characterized by doing.

Further, in the method of adjusting the optical disk apparatus according to the present invention, the servo gain of the servo means is initially adjusted in a state where the servo is applied to the objective lens of the optical head at an arbitrary position on the optical disk in the radial direction. Performing, determining the presence or absence of the recording data at the arbitrary position on the optical disc, correcting the initially adjusted servo gain based on the determination result of the presence or absence of the recording data, Storing the corrected servo gain adjustment result so that the servo gain is set for the servo means during recording or reproduction of the optical disk.

Further, in the adjusting method of the optical disk device according to the present invention, the optical disk is a recordable / reproducible disk having a higher light reflectance in a non-recording area than in a recording area, and the servo gain is corrected in the step of correcting the servo gain. The correction is made to increase the gain when it is determined that there is recording data at the position on the optical disk where the servo gain has been initially adjusted, and to reduce the gain when it is determined that there is no recording data. It is characterized by doing.

As described above, according to the present invention, the initial adjustment of the loop gain is performed with the servo, that is, the focus servo or the tracking servo applied to the objective lens (and the optical head main body) of the optical head. Whether the position (track) on the optical disk traced by the objective lens of the optical head is a data recording area,
And detects whether the non-storage area, and fine adjustment of the servo gain in response to the detection result, and stores holding the adjustment result of the fine adjustment servo gain.

Therefore, according to the present invention, at the time of reproduction or recording of, for example, a DVD-RAM or the like in which a recording area / non-recording area having different laser beam reflectivities coexist, the servo gain is set between the recording area and the non-recording area. For example, it is possible to read out the adjustment result finely adjusted so as to have an average servo gain and to reproduce or record such an optical disk in a state in which the gain is set, so that the entire area of the optical disk such as a DVD-RAM can be read. Thus, a gain margin and a phase margin can be secured, and a stable servo characteristic can be exhibited in the optical disk device.

Here, in the present invention, the optical disk is a recordable / reproducible disk having a higher reflectance of light in a non-recording area than the reflectance of light in a recording area, and an initial adjustment of a servo gain on the optical disk. When there is recording data at the position, correction is, of course, made to increase the gain, and when there is no recording data, adjustment is made to decrease the gain.

In the present invention, the presence or absence of the recorded data at the position on the optical disk where the servo gain has been initially adjusted can be used, of course, based on the signal obtained from the optical disk through the optical head. The determination can be made from the detection result of the generated full addition signal, error correction signal, or synchronization signal. As a result, the influence of the presence or absence of data on the optical disk can be minimized with a simple configuration without using an AGC circuit or the like, and the optical disk device can exhibit stable servo characteristics.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a configuration of an optical disk device according to an embodiment of the present invention.

As shown in FIG.
Is, for example, a DVD capable of recording / playback of high-density data
A RAM drive device, which is an optical disk (DVD-
While the (RAM) 101 is driven to rotate by the spindle motor 102, information is recorded / reproduced via the optical head 103. The optical head 103 drives the optical disc 1 by the feed motor 104 during recording and reproduction of the optical disc 101.
01 in the radial direction. Also, the optical head 103
Are driven in a focus direction and a tracking direction of the optical head 103 by, for example, an actuator 105 using an electromagnetic coil.

FIG. 2 is a diagram showing the configuration of the optical system of the optical head 103. In the figure, a laser beam emitted from a semiconductor laser 201 as a light source is collimated by a collimator lens 202, guided to an objective lens 204 via a beam splitter 203, and narrowed down by the objective lens 204. Then, the light is irradiated on the recording surface of the optical disc 101 as a minute spot. The reflected light from the optical disk 101 irradiated with the laser beam in this way reflects off the beam splitter 203 and
5 guides the light to a photodetector 206 comprising a multi-segment detector.

The output signal of the photodetector 206 is input to the analog operation circuit 106. In the analog operation circuit 106, the objective lens 20 with respect to the recording surface of the optical disc 101 is
4, a focus error signal FE indicating an error of the focus position (focus error), and a tracking error signal TE indicating an error (tracking error) of the position of the irradiation laser beam with respect to the track on the optical disk 101 in the tracking direction (radial direction of the optical disk 101). , And a full sum signal RF.

FIG. 3 shows a specific configuration of the photodetector 206 and the analog arithmetic circuit 106. The photodetector 206 includes four divided areas 21 each having a detection surface divided into two in the track tangential direction and the track width direction of the optical disc 101.
It is a quadrant detector having 1, 212, 213, 214. When the output signals from the divided areas 211, 212, 213 and 214 to A, B, C, and D, respectively, the optical detector 206, an analog operation circuit 106, FE = (A +
C)-(B + D), TE = (A + B)-(C + D), R
By the calculation of F = (A + B + C + D), a focus error signal FE, a tracking error signal TE, and a full addition signal (high-frequency signal) RF are generated.

The analog operation circuit 106 includes the photodetector 2
-Current conversion amplifiers 221 to 224, 231 to 23 for converting the output signal (current signal) 06 into a voltage signal
4, 241 to 244 and a focus error signal calculation unit 2
51, a tracking error signal calculation section 252 and a full addition signal calculation section 253 are provided. Here, the current-voltage conversion amplifier 2 inserted before the focus error signal calculation unit 251 and the tracking error signal calculation unit 252
21 to 224 and 231 to 234 are configured by variable gain amplifiers, and the gain is controlled by a balance control signal BC from a system controller 120 described later.

Here, the optical disk device 10 of the present embodiment
The reproduction operation based on 0 will be schematically described. As shown in FIG. 1, when information recorded on the optical disk 101 is reproduced, a reproduced signal corresponding to the information recorded on the optical disk 101 appears in the full addition signal RF signal output from the analog arithmetic circuit 106. The full addition signal RF is input to the data extraction circuit 117 via the header signal detection circuit 116, where the data signal portion is extracted and binarized, and the bit clock and the synchronization signal are extracted and generated. Is done.

The binarized signal by the data extraction circuit 117 is input to the CD / DVD data signal processing circuit 118, error correction using the demodulation and ECC for RAM119 here is performed. CD / DVD data signal processing circuit 118
The signal demodulated and error-corrected by the encoder / decoder 1 is controlled by the system controller 120.
21 or input to the data buffer 122.

Next, the recording operation of the optical disk device 100 will be schematically described. A data signal input from the outside is buffered in the data buffer 122,
After the ID data, parity bit, etc. are added by the CD / DVD data signal processing circuit 118, the ECC RAM
Error correction coding (ECC encoding) using 119 and modulation are performed. The data signal after the error correction encoding / modulation is input to the LD driver 123 while being synchronized with the bit clock, and the LD driver 123 drives the semiconductor laser 201 of FIG. The signal is recorded.

On the other hand, header information is written in the optical disk 101 in advance in the form of pre-pits or the like. When the optical head 101 reads the header information during recording / reproduction on the optical disk 101, all the information output from the analog arithmetic circuit 106 is output. header signal is detected by the header signal detecting circuit 116 from the added signal RF. The detected header signal is supplied to the system controller 120, and the optical disk 1
01 is used for servo control in the header part,
The data extraction circuit 117 is used for information extraction in the header.

Further, the rotation speed control of the optical disk 101 by the optical disk device 100 will be described. The rotation speed control method of the optical disk 101 is roughly classified into CLV
There are a (constant linear velocity) method and a CAV (constant angular velocity) method, and the spindle motor 102 is driven by different methods according to these methods. That is, when the rotation speed control method of the optical disk 101 is the CLV method, the synchronization signal extracted by the data extracting circuit 117 is supplied to the spindle motor control circuit 124 and the linear velocity (with the optical disk 101 and the irradiation The rotational speed of the spindle motor 102 is controlled so that the relative speed of the laser beam is constant. Also, the optical disk 1
When the rotational speed control method of the optical disk 01 is the CAV method, the FG signal generated inside the spindle motor 102 is supplied to the spindle motor control circuit 124, and the angular velocity, that is, the optical disk 1
01 so that the rotation speed of the spindle motor 1 is constant.
02 is controlled.

Next, the tracking servo system and the focus servo system of the optical disk device of the present embodiment will be further described. As shown in FIG.
The tracking error signal TE output from 06 is input to the tracking servo equalizer 107, where gain and phase are compensated. Inside the tracking servo equalizer 107, the tracking error signal TE
Is input to a multiplier 110 for gain compensation. Gain multiplied by multiplier 110 (servo loop gain)
Is provided by the servo gain adjustment circuit 131 under the control of the system controller.

The tracking error signal after gain and phase compensation output from the tracking servo equalizer 107 is supplied to the feed motor 104 via the feed motor control circuit 112 and the feed motor driver 113. The feed motor 104 is driven by a feed motor driver 113 under the control of a feed motor control circuit 112, and controls the optical head so that the laser beam from the optical head 103 scans a target track specified by a system controller 120 described later. 103 is an optical disk 101
In the radial direction.

The tracking error signal TE after gain and phase compensation output from the tracking servo equalizer 107 is supplied to the feed motor 104 via the feed motor control circuit 112 and the feed motor driver 113. The feed motor 104 is driven by a feed motor driver 113 under the control of a feed motor control circuit 112, and controls the optical head so that the laser beam from the optical head 103 scans a target track specified by a system controller 120 described later. 103 is moved in the radial direction of the optical disk 101.

The output signal of the tracking servo equalizer 107 is further supplied to an actuator driver 114 for tracking. The actuator 105 is driven by the actuator driver 114 and moves the laser beam emitted from the optical head 103 onto the optical disc 101 in the tracking direction (radial direction of the optical disc 101) so that the tracking error becomes zero.

On the other hand, the focus error signal FE output from the analog arithmetic circuit 106 is input to a focus servo equalizer 108, where gain and phase are compensated. The multiplier 111 in the focus servo equalizer 108 is for gain compensation, and the gain multiplied by the multiplier 111 (servo loop gain) is
Gain adjustment circuit 131 under the control of the system controller
Given by

The focus error signal after gain and phase compensation output from the focus servo equalizer 108 is used as the focus servo actuator driver 11.
5 is supplied. The actuator 105 is driven by an actuator driver 115, and controls the objective lens 2 in the optical head 103 so that the focus error becomes zero.
04 is moved in the focusing direction (optical axis direction).

The focus error signal FE and the tracking error signal T output from the analog operation circuit 106
E is also input to the automatic gain adjustment circuit 131, and the tracking error signal TE and the full addition signal RF are also input to the automatic balance adjustment circuit 132.

The gain adjusting circuit 131 sets a focus servo loop gain (hereinafter, referred to as “focus gain”) and a tracking servo loop gain (hereinafter, referred to as “tracking gain”) under the control of the system controller 120. The gain is adjusted by supplying the gain control signal GC to the multiplier 110 in the focus servo equalizer 107 and the multiplier 111 in the tracking servo equalizer 108, and the adjustment result is stored in a register 151 described later. I do.

On the other hand, the balance adjustment circuit 132 adjusts the balance of the focus error signal FE and the balance of the tracking error signal TE in the analog arithmetic circuit 106 under the control of the system controller 120. current in the analog operation circuit 106 a signal BC - voltage amplifier 221-22
4, the adjustment is performed by supplying the gain control signals to 231 to 234, and the adjustment results are stored in registers (not shown).

Here, the servo gain adjustment circuit 131 provided in the optical disk device 100 according to the present embodiment will be described in detail.

The servo gain adjusting device 131 can automatically adjust the focus gain or the tracking gain at the time of manufacturing the optical disk device 100.
At the time of normal recording / reproduction.
This is a circuit for reading out the adjustment result stored in 51 and setting it to the servo equalizers 107 and 108, respectively, so that the servo characteristics of the optical disk device 100 approach the designed ideal characteristics.

That is, the servo gain adjusting device 13
As shown in FIG. 4, reference numeral 1 denotes a sine wave (reference wave) having a frequency of, for example, about 4 KHz to 6 KHz as a disturbance signal related to the resonance characteristic of the actuator 105 of the optical head 103.
A sine wave generation circuit 152 for generating M, a focus error signal FE or a tracking error signal TE digitally converted via an A / D converter 153, and an adder 154 in the tracking servo equalizer 107 or the focus servo equalizer 108. M and phase compensation filter 155, D / A converter 1
A bandpass filter 156 for extracting a frequency component substantially the same as a sine wave from the signal N that has passed through the focus / tracking servo system after passing through 50 or the like, and a signal output from the bandpass filter 156 and a sine Wave M
157, a loop filter 158 for removing a high frequency component of the signal output from the phase comparison circuit, and an averaging / identification circuit for sampling and identifying the signal output from the loop filter 158. 1
In addition to the objective lens 20 of the optical head 103, when the loop gain is initially adjusted with focus servo or tracking servo applied to the objective lens 204 of the optical head 103 (and the main body of the optical head 103).
Position (track) on the optical disk traced in step 4
But whether the recording area of the data, determines data existence judging circuit 160 whether the non-storage area, and on the basis of the data existence signal outputted from the data existence judging circuit 160, corrects the servo gain is initially adjusted Gain fine-tuning unit 162 comprising a gain correction table 161 for outputting a signal for performing the adjustment, the output signal of averaging / identifying circuit 159 and the output signal of gain fine-tuning unit 162 are added, and the servo gain adjusted by this addition is adjusted. As a result, an adder 163 for storing and holding in the register 151 is provided.

The data presence / absence determination circuit 160 calculates the amplitude result of the full addition signal RF output from the analog operation circuit 106 and the CD / DVD data signal processing circuit 118, for example.
CD / DV regarding the error line number result of the error correction signal obtained through the system controller 120 or the synchronization signal extracted by the data extracting circuit 117.
System controller 12 via D signal processing circuit 118
Based on the VFO (Voltage Frequency Oscillator) detection result from 0, the presence or absence of recorded data at an arbitrary position on the optical disc 101 is determined.

Here, the optical disc 101 is a DVD in which recording areas / non-recording areas having different laser beam reflectivities are mixed.
As shown in FIG. 5, in the recording area, the phase shift between the response signal N obtained by superimposing the sine wave M on the focus error signal FE or the tracking error signal TE and the sine wave M Ideal deviation Φ0
(Deg), the deviation amount becomes Φb (deg), and the servo gain is-
It will be reduced by 3 dB.

On the other hand, in the non-recording area, the response signal N obtained by superimposing the sine wave M on the signal FE or the signal TE and the sine wave M
And the servo gain becomes a gain value +3 dB higher than the ideal gain of the design value.

Therefore, the gain correction table 161 has a calculation formula of H (correction gain [dB]) = (loop gain [dB] of unrecorded area−loop gain [dB] of recording area) / 2. . If the optical disc 101 is
In the case of the present embodiment which is a VD-RAM, H = 2 to 3
dB is a suitable correction gain value.

That is, when the data presence / absence signal received from the data presence / absence determination circuit 160 is a signal indicating the presence of data, the gain correction table 161 records information for adjusting the servo gain by, for example, 3 dB higher.
When the data presence / absence signal received from the data presence / absence determination circuit 160 is a signal indicating no data, information for adjusting the servo gain by 3 dB is recorded. As a result, the servo gain can be adjusted to an intermediate level of the recording / non-recording area, that is, a target design gain value.

Next, a method of adjusting the focus gain and the tracking gain which is automatically performed at the time of manufacturing the optical disk device 100 having the above-described structure will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG.

First, a state in which focus servo or tracking servo is applied to the objective lens 204 of the optical head 103 at an arbitrary position in the radial direction on the optical disk 101, that is, the track of the optical disk 101 is applied to the objective lens 204 (and the optical head 103). In the traced state, a sine wave M having a frequency of, for example, about 4 KHz to 6 KHz is generated as a disturbance signal, and the sine wave M is superimposed on the focus error signal FE or the tracking error signal TE.

The phase comparison circuit 157 measures the phase difference between the response signal N and the sine wave M that have returned through the focus / tracking servo system, and the averaging / identification circuit 159 identifies the signal. The initial adjustment of the focus gain or tracking gain is completed (S1).

Next, the objective lens 204 of the optical head 103 on the optical disk 101 in a state where the focus / racking servo is performed by the data presence / absence determination circuit 160.
Is detected (S2), and the presence or absence of the recording data at this initial adjustment position is determined (S3).

When the servo gain initial adjustment position is in the recording area (YES in S3), the data presence / absence determination circuit 160
, A signal indicating data presence is transmitted to the gain correction table 161, and a signal for adjusting the servo gain higher by H (+3) dB is transmitted to the adder 163 (S
4) On the other hand, when the initial adjustment position of the servo gain is in the non-recording area (NO in S3), the data presence / absence determination circuit 160
, A signal indicating no data is transmitted to the gain correction table 161, and a signal for adjusting the servo gain lower by H (−3) dB is transmitted to the adder 163 (S
5). ,

These signals for correction transmitted to the adder 163 are added to the signal output from the averaging / identifying circuit 159, that is, the signal of the initially adjusted servo gain to correct the initial gain. They are respectively stored and held in the focus gain and the register 151 as the final adjustment result of the tracking gain and. In such a process, the adjustment of the servo gain is automatically completed.

Thereafter, at the time of recording / reproducing of the optical disk 101, each adjustment result of the tracking gain or the servo gain recorded in the register 151 is sent to the multipliers 100 and 111 of the focus servo equalizer 107 and the tracking servo equalizer 108, respectively. By performing recording / reproduction by setting the gain as the gain control signal GC, it becomes possible to reproduce characteristics closer to the designed servo characteristics on an actual device.

As described above, the optical disc apparatus 100 of the present embodiment sequentially performs the initial adjustment of the loop gain with the focus servo or the tracking servo applied to the objective lens 204 (and the optical head body) of the optical head 103 individually. The optical disk 101 traced by the objective lens 204 of the optical head 103 at the time of the initial adjustment of the gain
Whether the upper position (track) is the data recording area,
In addition to detecting whether the area is a non-storage area, the focus gain and the tracking gain are finely adjusted according to the detection result, and the finely adjusted servo gain adjustment results are stored and held.

Therefore, according to the present embodiment, D where mixed recording / non-recording areas having different laser beam reflectivities are mixed.
At the time of reproduction or recording of the VD-RAM, an adjustment result obtained by finely adjusting the servo gain between the recording area and the non-recording area so as to have an average servo gain, for example, is read out. Since reproduction or recording can be performed, a gain margin and a phase margin can be secured over the entire area of the optical disc 101, and the optical disc apparatus 100 can exhibit stable servo characteristics.

As described above, the present invention has been described in detail with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. For example, CD-R and CD other than DVD-RAM
The present invention may be applied to a drive device for recording / reproducing recording / reproducing media such as RW.

[0059]

As described above, according to the present invention, the position on the optical disk traced by the objective lens of the optical head at the time of the initial adjustment of the gain of the focus servo or tracking servo is the data recording area. And the servo gain is corrected in accordance with the detection result, and the corrected result can be stored and held. For example, a DVD in which recording areas / non-recording areas having different light reflectivities coexist. -In a RAM or the like, it is possible to perform reproduction or recording of this optical disc in a state where the servo gain is set to be an average servo gain between the recording area and the non-recording area, thereby stabilizing the optical disc apparatus. Servo characteristics can be exhibited.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an optical disk drive device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an optical system provided in the optical disk device of FIG.

FIG. 3 is a diagram illustrating a photodetector and an analog arithmetic circuit that constitute a part of the optical system of FIG. 2;

FIG. 4 is a block diagram showing in detail a servo gain adjustment circuit constituting the optical disk device of FIG. 1;

FIG. 5 is a diagram illustrating phase characteristics of a servo closed loop of the optical disk device of FIG. 1;

FIG. 6 is a flowchart showing a method for adjusting a servo loop gain of the optical disk device of FIG. 1;

[Explanation of symbols]

100 optical disk device, 101 optical disk, 103
... optical head, 104 ... feed motor, 105 ... actuator, 106 ... analog arithmetic circuit, 107 ... tracking servo equalizer, 108 ... focus servo equalizer, 110, 111 ... gain multiplier, 117 ... data extraction circuit, 118 ... CD / DVD Data signal processing circuit, 119: ECC RAM, 120: system controller, 131: servo gain adjustment circuit, 151: register, 152: sine wave generation circuit, 157: phase comparison circuit, 160: data presence / absence determination circuit, 161: gain Correction table, 162: Gain fine adjustment unit, 204: Objective lens.

Claims (5)

[Claims] And 1. A optical head, a servo means for servo control on the objective lens of the optical head, a servo on the objective lens of the optical head by said servo means at an arbitrary position in the radial direction on the optical disk Initial adjustment means for initially adjusting the servo gain of the servo means in a state where the data is applied; data presence / absence determination means for determining the presence / absence of recording data at the arbitrary position on the optical disc; Gain correction means for correcting the servo gain that has been initially adjusted by the initial adjustment means, and the servo gain corrected by the gain correction means is set for the servo means during recording or reproduction of the optical disk. Storage means for storing and holding the corrected servo gain adjustment result. Optical disk apparatus according to symptoms. 2. The optical disc device according to claim 1, wherein the optical disc is a recordable / reproducible disc having a higher reflectance of light in a non-recording area than in a recording area, and wherein the gain correction means is provided on the optical disc. Correction to increase the gain when the data presence / absence determination means determines that there is recording data at the arbitrary position, and correction to decrease the gain when it is determined that there is no recording data. Characteristic optical disk device. 3. The optical disk device according to claim 1, wherein said data presence / absence determining means includes a full addition signal, an error correction signal, or a synchronization signal generated based on a signal obtained from said optical disk through said optical head. An optical disc device, wherein the presence or absence of recorded data on the optical disc is determined based on a detection result. 4. A step of initially adjusting the servo gain of the servo means while servo is applied to the objective lens of the optical head by the servo means at an arbitrary position in the radial direction on the optical disc; Determining the presence / absence of recording data at a position; correcting the initially adjusted servo gain based on the determination result of the presence / absence of the recording data; and wherein as set for the servo means adjusting method of an optical disk apparatus characterized by a step of storing and holding the adjustment results of the corrected servo gain. 5. The method for adjusting an optical disk device according to claim 4, wherein the optical disk is a recordable / reproducible disk having a higher light reflectance in a non-recording area than in a recording area, and correcting a servo gain. In the above, when it is determined that there is recording data at the position on the optical disk where the servo gain is initially adjusted, the gain is corrected so as to increase the gain,
And a correction method for lowering the gain when it is determined that there is no recording data.