JPH03259427A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain normal tracking servo by detecting the maximum value of a tracking error signal and its minimum value or the both in the vicinity of the maximum and minimum values at the time of starting focus servo, and adjusting the gain of the tracking servo depending on the difference between both the values. CONSTITUTION:When an optical pickup 10 moves up to a home position along the radial direction of an optical disk 1 and the optical disk 1 is rotated once and only the focus servo is initiated, a servo gain adjustment means 70 detects a maximum value and a minimum value or both the values in the vicinity of the maximum and minimum values of tracking error signals S32, S34 and S71 and obtains a difference between both the values, and acts like adjusting the tracking servo gain based on the obtained difference. Thus, the tracking servo gain is automatically adjusted to set the gain in response to an optical disk medium in use and normal recording and reproduction is attained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an optical information recording/reproducing device such as a write-once type or a read-only type optical disk device, or an erasable/rewritable magneto-optical disk device; In particular, the present invention relates to an optical information recording and reproducing device that is equipped with an automatic tracking servo gain adjustment function and is compatible with recording media such as optical disks and magneto-optical disks (hereinafter collectively referred to simply as "optical disk media").

(Conventional technology) Conventionally, as a technology in this field, Kazuo Terada, "Key Points of Optical Pickup System Design", [6]
-10-31> Japan Industrial Technology Center, P, 151, 1
52,161.

As described in this document, a conventional optical information recording/reproducing device, for example, an optical disk device, irradiates a light beam onto a recording layer provided on an optical disk, which is an optical disk medium, and the reflected light causes a focus error ( an optical pickup that detects focusing errors) and tracking errors (tracing errors with respect to tracks on an optical disk) and outputs detection signals for controlling focus servo and tracking servo; and outputs focus error signals and tracking error signals from the detection signals. a servo error signal generation means; a drive means for outputting a focus drive current and a tracking drive current based on the focus error signal and the tracking error signal; and an actuator for moving in the tracking direction.

In this optical disc device, for example, a spindle motor rotates the optical disc, and a drive unit moves an optical pickup in a focusing direction and a tracking direction via an actuator based on a focus error signal and a tracking error signal output from a servo error signal generating means. Feedback control (servo) is performed to eliminate focus errors and tracking errors, and the information on the optical disc is read.

In this type of optical information recording and reproducing device, the optical disk medium records and reproduces information by optical means, so it has the characteristics of large capacity and long life, and is used for various purposes such as document files. has been done.

(Problems to be Solved by the Invention) However, the apparatus with the above configuration has the following problems.

In conventional optical information recording and reproducing devices, such as optical disk devices, optical disks are generally not compatible, and types of optical disks that can be used normally are specified for each manufacturer or model.

That is, in general, when looking at the characteristics of various types of optical disks, they have almost the same characteristics in terms of reflectance and recording sensitivity. This is because when forming the recording layer, the material and amount to be deposited or sputtered can be controlled relatively easily.

However, there are tracks (pre-prepared on an optical disc)
The depth and shape of the grooves differ for each type of optical disc, that is, for each optical disc that can be used in a specific optical disc device.

For this reason, when different types of optical discs are used in the same optical disc device, the amplitude of the tracking error signal obtained by the optical pickup will differ significantly. Therefore, if the tracking gain of an optical disk device is adjusted to suit a certain type of optical disk, for other types of optical disks, if the amplitude of the resulting tracking error signal is large, the tracking gain will become too high and the tracking servo loop will On the other hand, if the amplitude of the obtained tracking error signal is small, the tracking gain becomes insufficient, leading to an increase in tracking error.

Due to these problems, conventional optical disc devices
The optical discs were not compatible, and it was not possible to take full advantage of the portability (replaceability) of the optical disc, which is one of the major advantages of optical disc devices.

In order to improve the performance of optical disk devices, there is a need to improve access time and reduce costs, but in particular, the problem of compatibility of optical disk media is one that needs to be resolved first. Met.

Such problems are not limited to optical disk devices;
For example, this problem also occurs in magneto-optical disk devices.

The present invention provides an optical information recording and reproducing device that solves the problem of the prior art in that the amplitude of the tracking error signal varies greatly depending on the optical disk medium used, and normal tracking servo is not performed. It is something to do.

(Means for Solving the Problems) In order to solve the above problems, the present invention irradiates a light beam onto an optical disk and outputs a detection signal for controlling a focus servo and a tracking servo from the light from the optical disk. a servo error signal generating means for generating a focus error signal and a tracking error signal based on the detection signal; and a driving means for outputting a driving current for focusing and tracking based on the output of the servo error signal generating means. , an optical information recording/reproducing apparatus comprising an actuator for moving the optical pickup in a focusing direction and a tracking direction using the driving current, and a servo gain adjusting means is provided.

Here, the servo gain adjustment means detects a maximum value and a minimum value of the tracking error signal at the time of starting the focus servo, or both values in the vicinity thereof, and adjusts the gain of the tracking servo based on a subtracted value between the two values. It has a function.

(Function) According to the present invention, since the optical information recording/reproducing device is configured as described above, for example, the optical pickup moves to the home position along the radial direction of the optical disc after power is turned on or after disc loading (installation). However, when the optical disk rotates and only the focus servo starts, the servo gain adjustment means detects the maximum value and the minimum value of the tracking error signal, or both values in the vicinity thereof, calculates the subtracted value of both values, and calculates the subtracted value between the two values. It works to adjust the tracking servo gain based on the obtained subtraction value.As a result, the tracking servo gain is automatically adjusted and the gain is set according to the optical disc medium used, allowing normal recording and playback operations. .

Therefore, the above problem can be solved.

(Embodiment) FIG. 1 shows a first embodiment of the present invention, and is a block diagram of a configuration of a magneto-optical disk device, which is one of optical information recording and reproducing devices.

In this magneto-optical disk device, an optical pickup 10 is provided near an optical disk 1 that is rotated by, for example, a spindle motor. This optical pickup 10 irradiates a light beam onto the optical disc 1 and outputs a detection signal FE for focus servo control and a detection signal TE for tracking servo control from the reflected light, and also outputs a detection signal FE for focus servo control and a detection signal TE for tracking servo control.
It has a function of outputting reproduction detection signals PDI and PD2 of recorded information. This optical pickup 10 includes a semiconductor laser 11. Beam splitter 12, 14, objective lens 1
3. 1/4 wavelength plate 15, polarizing beam splitter 16, photodetector 17 for outputting reproduction detection signal PDI, photodetector 18 for outputting reproduction detection signal PD2, laser mirror 19, detection signal TE for tracking servo control
For example, a two-part photodetector 20 for outputting
, a cylindrical lens (plano-convex lens) 21, and a two-segment photodetector 22 for outputting a detection signal FE for focus servo control.

A servo error signal generation means 30 is connected to the output side of the photodetector 20.22.

The servo error signal generating means 30 generates a detection signal FE.

TE is input, and a servo error signal for focus servo and tracking servo, that is, focus error signal 831. S33 and tracking error signal S32. S
This circuit generates 34 and amplifies it. This servo error signal generation means 30 includes a differential amplifier 31 that generates a focus error signal S31 from the detection signal FE, a differential amplifier 32 that generates a tracking error signal S32 from the detection signal TE, and a differential amplifier 32 that amplifies the focus error signal S31. and an amplifier 34 that amplifies the tracking error signal S32 and outputs the amplified tracking error signal S34.

A driving means 50 is connected to the output side of the amplifier 33 via a phase compensation port fa40 for compensating for phase lag and lead, and a notch filter (narrowband filter) 42 for preventing focus high-order resonance. .

On the other hand, a driving means 50 is connected to the output side of the amplifier 34 via a phase compensation circuit 41.

The drive means 50 includes a focus side drive section 51 that performs voltage/current conversion on the output of the notch filter 42 and outputs a focus drive current f, and a focus side drive section 51 that performs voltage/current conversion on the output of the phase compensation circuit 41 and outputs a focus drive current f. The tracking side drive section 52 outputs a drive current It. An optical pickup 10 is provided on the output side of this driving means 50.
An actuator 60 equipped with is connected. The actuator 60 moves the objective lens 1 by means of an objective lens vertical drive coil operated by a focus drive current If.
3 in the focus direction, and also moves the optical pickup 10 in the radial direction of the optical disc 1 using the tracking drive current It.

Further, the amplifier 34 is connected to a servo gain adjustment means 70, which is a feature of this embodiment. The servo gain adjustment means 70 detects the maximum and minimum values of the amplitude of the tracking error signal S34 obtained when only the focus servo is on when starting the focus servo, calculates the subtracted value of both values, and calculates the subtracted value of the two values. It has a function to automatically adjust the tracking servo gain based on the subtraction value.

The servo gain adjustment means 70 includes, for example, an analog/digital converter (hereinafter referred to as A/D converter) 71 that converts an analog tracking error signal S34 into a digital signal, a maximum value register, and a minimum value register. A maximum/minimum value calculation unit 72 calculates the maximum and minimum values of the digital tracking error signal S71 output from the /D conversion unit 71, and calculates the maximum value of the tracking error signal S71 based on the output of the maximum/minimum value calculation unit 72. The amplitude calculation unit 73 is composed of an amplitude calculation unit 73 that calculates the subtraction value between the value and the minimum value and calculates the error with a predetermined amplitude reference value, and a digital/analog converter (hereinafter referred to as a D/A converter). It is composed of a gain setting section 74 that provides an output signal S74 for setting the tracking servo gain based on the calculation result to the amplifier 34.The maximum/minimum value calculation section 72 and the amplitude calculation section 73 are composed of a calculation unit, etc. It may consist of individual circuits, or it may consist of a central processing unit (hereinafter referred to as
It is executed under program control of a CPU (called a CPU).

Figure 2 shows the amplifier 3 on the tracking servo side in Figure I.
FIG. 4 is a circuit diagram showing an example of the configuration of No. 4. FIG.

This amplifier 34 includes an operational amplifier circuit A1 and an output signal S7.
tracking error signal S3
The input terminal of the operational amplifier circuit A1 is connected to the ground, for example. In the amplifier 34, the output signal S7
Depending on the signal value of 4, the resistance value R3d1 between the source (S) and drain (D) of the FET 1 changes, and the amplification factor changes.

The servo operation of the magneto-optical disk device configured as described above will be explained.

First, a light beam emitted from the semiconductor laser 11 in the optical pickup 10 passes through the beam splitter 12 and is focused onto the optical disc 1 by the objective lens 13 . The reflected light from the optical disk 1 passes through an objective lens 13 and a beam splitter 12, and is further split into beams for servo control and signal detection by a beam splitter 14. The separated light beam for signal detection is: 1. The light passes through the /4 wavelength plate 15 and is separated by the polarizing beam splitter 16 to obtain a magneto-optical signal and a preformat signal, which are reproduced signals, and are received by the photodetector 17. Here, the playback detection signals PDI and PD2 output from the photodetectors 17 and 18, respectively, are added (
=PD1+PD2), a preformat signal (ID signal) is obtained. This is a method in which signals such as track addresses and sector addresses are recorded in advance in the form of pits on the surface of an optical disk using concavities and convexities.

Furthermore, the playback detection signal PD1. PD2 differential (=PDI-
PD2>, a magneto-optical signal is reproduced.

This is a signal in which data is recorded by recording the magnetization direction of the recording layer in the optical disk 1 in the form of bits, and the magnetization direction, that is, "1" and "0" is reproduced by the Kerr effect.

Further, the light beam for servo control separated by the beam splitter 4 in the optical pickup 10 is transmitted to the laser mirror 1
9 , part of the light beam is split for tracking and the rest for focusing, and the tracking light beam is received by a two-segment photodetector 20 .

The focusing light beam is a cylindrical lens 2
1 and is received by the two-segment photodetector 22. One photodetector 20 outputs a detection signal TE for tracking servo control, and the other photodetector 22 outputs a detection signal FE for focus servo control, which are applied to differential amplifiers 31 and 32, respectively.

One differential amplifier 31 inputs the detection signal FE and outputs a focus error signal S31, and the other differential amplifier 32 inputs the detection signal TE and outputs a tracking error signal S32. The focus error signal S31 is
The focus error signal 833 is amplified by the amplifier 33 to become the amplified focus error signal S33, and the focus error signal 833 is subjected to phase compensation for delay and lead in the phase compensation circuit 40, and a notch filter for preventing high-order focus resonance. The signal is applied to the drive unit 51 via 42.

The output of the notch filter 42 is subjected to voltage/current conversion by a driving section 51, and the driving section 51 outputs a focusing driving current If to be supplied to the actuator 60. The actuator 6o performs focusing control by vertically moving the objective lens 13 using an objective lens vertical drive coil provided therein.

Further, the tracking error signal S32 outputted from the other amplifier 32 is amplified by the amplifier 34, and the amplified tracking error signal s34 is sent to the phase compensation circuit 41.
The drive unit 52 performs voltage/current conversion, and the tracking drive current It is output from the drive unit 52.
is output.

The actuator 60 is driven by this tracking drive current It, and tracking control is performed.

As described above, the objective lens 13 is driven so as to irradiate a precisely focused light beam onto the optical disc 1 in response to the surface wobbling of the rotating optical disc 1, and a focusing operation is performed. Furthermore, a tracking operation is performed along a track pre-stamped (formed) on the optical disc 1, a servo is performed so that the focus error signal S31 and the tracking error signal S32 become O, and data recording/reproducing operation is performed. is executed.

Next, a method for automatically adjusting the tracking servo gain will be explained with reference to FIGS. 3, 4, and 5.

In addition, FIG. 3 is a waveform diagram showing the tracking error signal S34 when only the focus servo is on, FIG. 4 is a flowchart of maximum and minimum value calculation in the servo gain adjustment means 70 of FIG. 1, and FIG. It is a flowchart of settings.

First, the power is turned on or the disc is loaded, the optical pickup 10 is moved to the home position by the actuator 60, and the optical disc is rotated.

Thereafter, a focus search operation is started by a control signal from a control circuit including a CPU (not shown), and only the focus servo operates. At this time, the tracking error signal S34 outputted from the amplifier 34 crosses, for example, several tens of tracks because the optical disc 1 normally has disc eccentricity. Therefore, as shown in Figure 3,
A tracking error signal S34 is obtained having an output waveform that oscillates between the maximum amplitude TEmax and the minimum amplitude TEmin.

When the servo gain adjustment means 70 receives the tracking error signal S34, it adjusts the tracking error signal S3.
4 is converted into a digital signal by the A/D converter 71. The tracking error signal S71 converted into a digital signal is converted into the maximum value (TEmax in FIG. 3) and the minimum value (TEmax in FIG. TEmin> in the figure is calculated.

That is, in the flowchart of FIG. 4, when maximum and minimum value calculations are started, in step 100, the minimum value register Rmin in the maximum and minimum value calculating section 72 is set to an initial value of 10000, and the maximum value register Rmax is set as an initial value. For example, O is set as the value. In step 101,
The value of the tracking error signal S71 is the minimum value register R
It is determined whether the value is smaller than the content of min. If it is smaller, the content of the minimum value register Rmin is replaced with the value of the tracking error signal 871 in step 102. In step 101, when the value of the tracking error signal S71 is larger than the contents of the minimum value register Rmin, the contents of the minimum value register Rmin are left unchanged.

Next, in step 103, it is determined whether the value of the tracking error signal S71 is greater than the content of the maximum value register Rmax. If the value is larger than that, in step 104, the contents of the maximum value register Rmax are replaced with the value of the tracking error signal S71, and the tracking error signal S
When the value of 71 is smaller than the contents of the maximum value register Rmax, the contents of the maximum value register Rmax are left unchanged.

The above arithmetic processing is performed through step 105, for example, in 5 steps.
Repeat for 00m5 to find the maximum and minimum values.

In addition, in step 105, since there are generally variations in disk eccentricity and the number of waves of the tracking error signal S34 differs depending on the optical disk 1, the maximum and minimum value calculation processing is repeated for several times, for example, 500 m5 of the optical disk 1. This is desirable. However, this time of 500 m5 may be set to a desired time shorter than this.

When this maximum and minimum value calculation process is completed, the amplitude calculation section 73
Calculation processing for tracking servo gain setting is performed. The method of setting the tracking servo gain by the amplitude calculating section 73 will be explained using the flowchart shown in FIG.

In the flowchart of FIG. 5, when the calculation process is started, the amplitude calculation unit 73 performs D
/Initial value of gain setting section 74 consisting of A converter■
Set α and initialize. Then, gain setting section 7
The output signal S74 of 4 is output from the FE in the amplifier 34 shown in FIG.
It is input to the gate (G) of T1. Thereby, the amplification factor of the amplifier 34 is set. Next, in step 201,
After the maximum and minimum value calculation unit 72 calculates the maximum and minimum values of the tracking error signal S71 at the set initial value α, the amplitude calculation unit 73 performs step 202.
Then, the subtracted value TEmax-TEm of the maximum value and minimum value is
in is calculated, and in step 203, the subtraction value TEmax-
Compare TEmin with the amplitude reference value ■gS, and calculate Δv
Calculate the error of gs=vgs(TEmax-TEmin).

Furthermore, in step 204, it is determined whether or not the absolute value of ΔVgS is less than or equal to a predetermined threshold value β, and if the determination result is not less than or equal to the threshold value β, in step 205, D /A converter set value ■α
=Vα+ is corrected by Δvgs (a constant of 1) and reset.

The reset output signal S74 of the D/A converter in the gain setting unit 74 is applied to the gate (G) of FET1 of the amplifier 34.
input to the terminal. The resistance value of this FET1 changes depending on the gate voltage, and when the gate voltage increases, the source (S
) and drain (D>) decreases, and the input resistance of the amplifier 34 decreases, so the amplification factor R of the amplifier 34 decreases.
f/Rsd1 increases. For example, the subtracted value TEmax-TEmin of the obtained tracking error signal 871
is smaller than the amplitude reference value ■gS, Δ■gS becomes a positive value, and the value of Vα reset by the gain setting unit 74 becomes larger than the previous value of Vα, and the output signal S74
The signal value, that is, the gate voltage value of FET1 becomes high. Therefore, the gain of the amplifier 34 increases, and the amplitude of the tracking error signal S34 increases. This is repeated and when the absolute value of Δvgs becomes equal to or less than the threshold value β, it is assumed that the standard tracking servo gain is secured, and the tracking servo is turned on in step 206. Also,
Subtraction value TEmax-T of tracking error signal 871
Even when Emin is larger than the amplitude reference value vgs, the controller operates in the same manner and if it is determined that the reference tracking servo gain is secured, the tracking servo is turned on in step 206.

As described above, in the magneto-optical disk device of this embodiment, even if different types of optical disks are used and the amplitude value of the tracking error signal is different for each optical disk,
This has the advantage that the tracking servo gain is automatically adjusted by the servo gain adjustment means when the power is turned on or when loading is started, depending on the amplitude value of the tracking error signal specific to the optical disc used. Therefore, the magneto-optical disk device of this embodiment makes it possible to have optical disk compatibility, has excellent portability (replaceability), and enables stable tracking servo operation with minimum tracking error. .

FIG. 6 shows a second embodiment of the present invention, and is a circuit diagram of a servo gain adjusting means 70a.

This servo gain adjustment means 70a is provided, for example, in place of the servo gain adjustment means 70 in the magneto-optical disk device shown in FIG.

This servo gain adjustment means 70a has a function of performing the same operation as the servo gain adjustment means 70 in an analog manner,
Maximum amplitude detection port #l70a-1. Minimum amplitude detection circuit 70
a-2, a differential detection circuit 70a-3, a sample and hold circuit 70a-4, and an inverter circuit #170a-5.

The maximum amplitude detection circuit 70a-1 rectifies and smoothes the maximum side of the output waveform of the tracking error signal S34, and includes diodes D1. It has a capacitor C1 and a resistor R1, and the minimum amplitude detection circuit 70a-2 rectifies and smoothes the minimum side of the tracking error signal 834, and has a diode D2, a capacitor C2, and a resistor R2. Here, for example, the resistors R1 and R2 have the same resistance value R, and the capacitors C1 and C2 have the same capacitance C. Furthermore, a resistor R1 and a capacitor Cl,
The resistance R2 and the capacitor C2 have a smoothing time constant T=RXC of, for example, 10 times or more of one period of the tracking error signal S32 and a gain setting interval of 500 m.
It is set to about 5 or less Looms.

The differential detection port i'J70a-3 has an input resistance Ri 1°R
i2, a feedback resistor Rfl, a reference resistor Rf2, and a differential amplifier circuit A2. Here, for example, the input resistance Ril
and Ri2 have the same resistance value Ri, and the feedback resistance Rfl
and the reference resistance Rf2 have the same resistance value Rf.

The sample and hold circuit 70a-4 has the following characteristics:
It has a FET2 whose gate is controlled by a TT signal St, a capacitor Cs, and a buffer B1.

The inverter circuit 70a-5 is composed of, for example, an inverting amplifier.

Next, the operation of the servo gain adjusting means 70a will be explained with reference to FIG.

Tracking error signal S3 from the output side of amplifier 34
4 is input to the servo gain adjustment means 70a, the maximum amplitude detection diagram #170a-1 and the minimum amplitude detection circuit 70a
-2 holds the maximum and minimum peaks of the tracking error signal S34, respectively. As a result, on the maximum side of the tracking error signal S34, the signal 534a
is smoothed and held, and on the minimum side the signal 534b
is smoothed and held. Each signal 534a and 5
34b is TEmax for diode Di, D2;
Each voltage is about 0.5V lower than TEmin. The smoothed signals 534a and 534b are output to the amplitude detection circuit 70a-3.

In the amplitude detection circuit 70a-3, the signals 534a and 534
When TE
max-TEmin is calculated and the result of the calculation is output to the sample hold circuit 70a=4.

In the sample and hold circuit 70a-4, while the tracking servo is off, the run-7 signal St is at a high level, so the resistance value Rsd2 between the source (S) and drain (D) of the FET2 is several tens to several tens of times. 100Ω, and the output of the differential amplifier circuit A2 charges the capacitor Cs. When the tracking servo is turned on, the run
- Han signal St becomes low level, and resistance value Rsd2 of FET2 becomes several MΩ. As a result, the output of the differential amplifier circuit A2, which has been charged in the capacitor Cs, is
It is held and becomes an output signal S74 through the inverter circuit 70a5, and is output to the gate (G) of the FETI of the amplifier 34.
) terminal. As a result, the gate voltage of FET1 changes according to the signal value of output signal S74, and amplifier 3
The amplification factor of 4 is controlled, the tracking servo gain is automatically adjusted, and the tracking servo is operated.

In the servo gain adjustment means 70a, the amplitude reference value corresponding to vgs of the servo gain adjustment means 70 is the set value of Rf/Ri of the differential amplifier BA2, and the amplification factor Rf/Ri is the set value of the differential amplifier BA2.
As Ri increases, the amplification factor of the amplifier 34 decreases, and the tracking servo gain tends to decrease. This Rf/Ri
The amplitude reference value is set by setting the value.

As described above, the servo gain adjustment means 70a can also perform the automatic adjustment of the tracking servo gain that was digitally performed by the servo gain adjustment means 70 in FIG. Almost the same action and effect can be obtained.

Furthermore, an advantage of this second embodiment is that there is no need to perform program processing, and the processing speed can be increased.

Note that the present invention is not limited to the illustrated embodiment, and various modifications are possible. Examples of such modifications include the following.

(i> The circuit configuration of the servo gain adjustment means 70 and 70a can be modified. For example, the FETs 1 and 2 can be configured with ordinary transistors.

(ii) The optical pickup 10, servo error signal generating means 30, etc. shown in FIG. 1 can also be modified into circuit configurations other than those shown.

(iii) Although the above embodiment has been explained using a magneto-optical disk as an example, the present invention can be widely applied to write-once type and read-only type optical disk devices.

(Effects of the Invention) As described in detail above, according to the present invention, since the servo gain adjustment means is provided, the maximum value and minimum value of the tracking error signal can be adjusted at the time of starting the focus servo after turning on the power or after loading the disk. Alternatively, it is possible to detect both values in the vicinity thereof, obtain a subtracted value between the two values, and automatically adjust the tracking servo gain based on the obtained subtracted value.

As a result, even if the amplitude of the tracking error signal varies depending on the optical disk medium used, for example due to differences in the depth and shape of the track groove, the tracking servo gain can be automatically adjusted according to the optical disk medium. will be held.

Therefore, in the optical information recording/reproducing apparatus of the present invention, it is possible to make the optical disc medium compatible, and stable tracking servo operation with minimum tracking error is possible.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram of a magneto-optical disk showing a first embodiment of the present invention, FIG. 2 is a circuit diagram of an amplifier in FIG. 1,
Fig. 3 is a waveform diagram of the tracking error signal when only the focus servo is on, Fig. 4 is a flowchart of maximum and minimum value calculations, Fig. 5 is a flowchart of tracking servo gain setting, and Fig. 6 is a waveform diagram of the tracking error signal when only the focus servo is on. FIG. 3 is a circuit configuration diagram of a servo gain adjustment means showing an embodiment. 1... Optical disc, 10... Optical pickup, 30
... Servo error signal generation means, 31.32 ... Differential amplifier, 33.34 ... Amplifier, 50 ... Drive means, 51.52 ... Drive section, 60 ... Actuator, 70 .70a... Servo gain adjustment means, 71.
...A/D conversion section 72...maximum and minimum value calculation section, 73.
...Amplitude calculation section, 74...Gain setting section, FE...
Detection signal for focus servo control, TE...detection signal for tracking servo control, If...drive current for focus, It...drive current for tracking, PDI,
PD2...Reproduction detection signal, S31.833...Focus error signal, 832,834. S71...Tracking error signal.

Claims (1)

[Scope of Claims] An optical pickup that irradiates a light beam onto an optical disk and outputs a detection signal for controlling a focus servo and a tracking servo from the light from the optical disk, and a focus error signal and tracking based on the detection signal. servo error signal generation means for generating an error signal; drive means for outputting a drive current for focusing and tracking based on the output of the servo error signal generation means; and driving the optical pickup in the focus direction and the tracking direction using the drive current. In an optical information recording and reproducing apparatus, the optical information recording and reproducing apparatus includes an actuator for moving the tracking error signal, the maximum value and minimum value of the tracking error signal at the time of starting the focus servo, or both values in the vicinity thereof are detected, and the subtracted value of the two values is used to determine the tracking error signal. An optical information recording/reproducing device comprising: servo gain adjustment means for adjusting the gain of a tracking servo.