JP2001084605A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize focus control even when the influence of crossing a groove is large and to improve reliability by reducing control the gain of a focus control section to a prescribed value when a signal detected by a groove crossing quantity detecting section is larger than a prescribed level, and reducing rotation speed of information carrier by a rotation part to a prescribed value. SOLUTION: When a focus error signal exceeds a prescribed value decided by a groove crossing deciding section 26, a microcomputer 40 which receives the decision result by the groove crossing deciding section 26 reduces an amplifrication factor of a first gain adjusting section 28. Consequently, current flowing in a focus actuator 10 is reduced. Thereby, the damage of the actuator 10 can be prevented. Simultaneously, the computer 40 outputs a rotation speed decreasing command to a disk motor control section 31 as well, to reduce the output signals of the control section 31 and a disk motor driving circuit 33. Consequently, the increase of focus control residue with respect to the wobbling of the surface of an optical disk 36 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only information carrier in which information is recorded by uneven pits, an information carrier capable of recording and reproducing information by a difference in the amount of reflected light due to a phase change, or a read-only information carrier. The present invention relates to an optical disc apparatus for recording and reproducing information carriers in which areas and recordable areas are mixed, and is particularly effective for a stable focus control method.

[0002]

2. Description of the Related Art In a conventional optical disk apparatus, a rotating disk-shaped information carrier (hereinafter referred to as an optical disk) is condensed and irradiated with a light beam from a light source such as a semiconductor laser to record or reproduce a signal. I have.

When reproducing a signal with this optical disk device, a relatively weak light beam of a constant light amount is irradiated onto the optical disk, and the reflected light modulated by the optical disk is detected and reproduced. In signal recording, information is written on a recording material film on an optical disk by modulating the intensity of a light beam according to the signal to be recorded.
No. 0802).

FIG. 8 is a schematic diagram of a read-only optical disk. In FIG. 8A, reference numeral 36a denotes a read-only optical disk, and FIG. 8B shows an enlarged cross section of the optical disk 36a when cut perpendicular to the information surface of the optical disk 36a. The structure of the optical disc 36a will be described with reference to FIG. Reference numeral 100 denotes a base material of the optical disk 36a, which is mainly made of transparent plastic or the like. Reference numeral 102 denotes a reflective film, which is a thin metal film for reflecting a light beam irradiated to obtain information on the optical disc 36a.
00 is covered. Reference numeral 101 denotes a pit,
2 is a depression on the base material 100 covered with 2, and the information signal is recorded according to the presence or absence of the depression. A protection film 103 protects and covers the pits 101 and the reflection film 102. 104 is an information track, which is a pit 1 as an information signal
8 are arranged in the circumferential direction as shown in FIG. The information tracks 104 are spirally formed at a constant interval of about 0.74 μm.

[0005] Such a read-only disc is referred to as an RO
It is called M disk.

FIG. 9 is a schematic diagram of an optical disk capable of recording and reproducing. In FIG. 9A, reference numeral 36b denotes an optical disk capable of reproducing and recording. In FIG. 9A, 105 is R
It is an OM area and has the same structure as a ROM disk, and information is recorded as a row of pits 101. 106 is RAM
The area is covered with a phase-change recording film capable of phase change (not shown), and is an area where recording and reproduction are possible. The interval between the information tracks is about 0.74 μm in both the ROM area and the RAM area. FIG. 9B shows an enlarged cross section of the optical disc 36b when the RAM area 106 of the optical disc 36b is cut perpendicular to the information surface. In FIG. 9B, 1
09 is a recordable area in the user data area.
Reference numeral 06 denotes a land track which is formed of a convex groove, and 107 denotes a groove track which is a concave groove. Reference numeral 108 denotes an information track, which is a land track 106 and a groove track 107.
The information signal is expressed by an amorphous (non-crystalline) state and a crystalline state of the phase change film. Reference numeral 110 denotes an address area in which recording is not possible, and address information is recorded in advance as a row of pits 101 when the optical disc 36b is manufactured.

Hereinafter, such a disk is called a RAM disk.

A conventional optical disk reproducing apparatus for reproducing such a ROM disk and a RAM disk will be described.

FIG. 17 is a block diagram showing a configuration of focus control of a conventional optical disk device. FIG. 10 is a diagram illustrating division of the light receiving unit of the photodetector.

In FIG. 17, reference numeral 4 denotes an optical pickup module which collectively performs a process of generating a light beam and receiving light reflected from an optical disk. 36 is an optical disk,
There are an optically readable ROM disk and an optically readable and writable RAM disk. 2
Is a laser unit of the optical pickup module 4, which generates a light beam for reading information recorded on the optical disk 36. Reference numeral 1 denotes an objective lens that focuses a beam spot of a light beam generated and output by the laser unit 2 of the optical pickup module 4 on the optical disk 36 in order to read information from an information track on the optical disk 36. 1
Reference numeral 0 denotes a focus actuator which moves the objective lens 1 in a direction substantially perpendicular to the information surface of the optical disk 36 in order to adjust the focus of the beam spot of the light beam to the information surface of the optical disk 36. Reference numeral 3 denotes a first light receiving unit inside the optical pickup module 4, which receives the reflected light of the light beam irradiated on the optical disk 36 again through the objective lens 1, and receives the reflected light for processing by an electric circuit. It consists of a photodetector that generates a current according to the amount.

Here, the photodetector of the first light receiving section 3 will be described with reference to FIG. The photodetector is composed of four divided photodetectors 3A, 3B, 3C, and 3D as shown in FIG. 10, and the focus error signal, tracking An error signal can be generated.

Reference numerals 12, 13, 14, and 15 in FIG. 17 denote first, second, third, and fourth I / V converters, respectively, which are photodetectors of the first light receiving section 3 of the optical pickup module 4. The currents generated in 3A, 3B, 3C, and 3D are converted into voltages. This is to eliminate the influence of disturbance generated from other circuits. 16 is a first adder,
The outputs of the I / V converter 12 and the fourth I / V converter 15 are added. A second adder 17 adds the outputs of the second I / V converter 13 and the third I / V converter 14. 21
Is a second differential amplifier, which subtracts the output signal of the second adder 17 from the output signal of the first adder 16 to generate a focus error signal in order to generate a focus error signal. Reference numeral 24 denotes a first A / D converter, which converts a focus error signal, which is an analog signal, into a digital signal that can be processed. Numeral 35 denotes a DSP which calculates a drive output for focus drive from a focus error signal converted into a digital signal, and performs digital calculations such as a drive calculation of a disk motor.

Reference numeral 28 in the DSP 35 denotes a first gain adjustment unit which amplifies or attenuates a focus error signal as an input signal and outputs the signal. Reference numeral 29 denotes a phase compensating unit which uses the output signal of the first gain adjusting unit 28 as an input signal in order to secure a gain margin and a phase margin for focus control, and amplifies and outputs the signal at an amplification factor according to the frequency band. A phase characteristic of an output signal with respect to an input signal is changed. 30 is D / A
A focus drive output signal (phase compensation unit 29) calculated from the focus error signal inside the DSP 35 by the converter.
Is converted into an analog signal. A focus drive circuit 32 is a focus drive output signal (D / A converter 30) calculated and output by the DSP 35.
The focus actuator 10 is driven in accordance with the output signal of the focus actuator 10). Numeral 34 denotes a disk motor for rotating the optical disk 36. Reference numeral 31 denotes a disk motor control unit which controls the disk motor 34 to rotate at a target rotation speed. 33 is a disk motor drive circuit,
5 is a circuit that realizes driving in accordance with the disk motor drive output signal calculated and output in step 5. Reference numeral 11 denotes a transfer table on which the optical pickup module 4 and the objective lens 1 are installed, which substantially moves the light beam spot in the radial direction of the optical disk 36.

The focus control operation of the conventional optical disk apparatus configured as described above will be described below with reference to FIGS. First, in FIG. 17, a light beam generated from the laser unit 2 in the optical pickup module 4 is applied to an optical disk 36 (ROM disk, R disk).
In order to read information recorded on an optical disc 36, the information is focused on the optical disc 36 by the objective lens 1.

The light beam reflected by the reflection film 102 of the optical disk 36 returns to the optical pickup module 4 via the objective lens 1 again. The light beam reflected by the optical disk 36 is applied to the photodetector of the first light receiving section 3 through a path different from the incident light inside the optical pickup module 4. The photodetector has a four-divided structure as shown in FIG. 10, and the photodetectors 3A, 3B, 3C, 3
The light beam applied to the D portion is converted into a photocurrent according to the amount of light received. Thereafter, the photocurrent generated in the 3A section of the photodetector is converted into a voltage corresponding to the current amount by the first I / V converter 12 in FIG.

Similarly, the photocurrents generated in the 3B, 3C, and 3D sections of the photodetector are second, third, and fourth I / V, respectively.
The converters 13, 14, 15 convert the photocurrent into a voltage. First I / V converter 12 and fourth I / V converter 15
Are added by the first adder 16. Similarly, the voltages output from the second I / V converter 13 and the third I / V converter 14 are added by a second adder 17. That is, a sum signal of the light receiving units on the diagonal line of the photodetector in FIG. 10 is generated.

The sum signals generated by the first adder 16 and the second adder 17 are output from the output signal of the first adder 16 by the second differential amplifier 21 to the second adder 17. Subtract output signal.

This calculation is to calculate (3A light reception amount + 3D light reception amount)-(3B light reception amount + 3C light reception amount). By performing this calculation, the information surface of the optical disk 36 of the light beam is obtained. A focus error signal indicating the above convergence state is obtained (for example, JP-A-50-99561). This detection method is generally called an “astigmatism method”. In a far area where the light beam spot and the objective lens 1 are sufficiently separated, the light beam is susceptible to crossing of the groove, and the light beam is Is characterized in that the quality of the focus error signal is degraded by the influence of the traversing of the groove due to the influence of the ± first-order light of the reflected light when traversing.

Therefore, in an information recording system using pits such as a ROM disk, this noise is relatively small,
In a structure such as an AM disk (for example, a land-groove method), this noise component appears remarkably.

This focus error signal is transmitted to the DSP 35
Is digitized by the first A / D converter 24 inside the
The signal is amplified or attenuated by the first gain adjustment unit 28 in the DSP 35 and output. After that, in order to secure the gain margin and the phase margin of the focus control loop characteristic in the phase compensating unit 29, the output signal of the first gain adjusting unit 28 is used as an input signal, and the first signal is amplified at the amplification factor according to the frequency band. By amplifying and outputting the output signal of the gain adjustment unit 28, the phase characteristic of the output signal with respect to the input signal is changed.

After the operations of the first gain adjustment unit 28 and the phase compensation unit 29 are performed inside the DSP 35, the D / A converter 30 generates an analog drive signal.

A drive voltage is applied from the focus drive circuit 32 to the focus actuator 10 based on the analog drive signal.
0 is controlled so that the objective lens 1 is moved substantially perpendicularly to the optical disc 36 so that the beam spot of the light beam is focused on the information surface of the optical disc 36.
Hereinafter, this control is referred to as focus control.

Accordingly, since the objective lens 1 is controlled in accordance with the focus error signal, the beam spot of the light beam is originally located on the information recording surface of the optical disk 36, but when the light beam spot crosses the information track. The beam spot of the light beam is shifted due to the signal quality deterioration of the focus error signal due to the crossing of the groove.
6 is instantaneously controlled to a position different from the position on the information recording surface. In other words, the larger the noise component due to crossing the groove included in the focus error signal, the more unstable the focus control becomes in terms of the system. Especially when performing high-speed playback, the control cannot be stabilized, and the focus control often shifts. However, in general, the process of recovering from the loss of focus control consumes a great deal of time, which hinders the information reading performance. Further, in the worst case, a huge current flows through the focus actuator 10 based on instantaneous noise due to the influence of the groove crossing.
May lead to damage to

[0024]

As described above, in the focus control using the astigmatism method in the conventional optical disk apparatus, the fur area is easily affected by ± 1st order return light. That is, when the beam spot of the light beam traverses the information track of the optical disk, the influence of the groove crossing on the focus error signal appears remarkably, and the quality of the focus error signal deteriorates.

That is, when the beam spot of the light beam traverses the information track, a large disturbance enters the focus error signal, and as a result, the signal for driving the focus actuator is greatly violent. Due to this effect, there is a problem that the focus control is frequently lost, and in some cases, the focus actuator 10 is damaged.

The present invention has been made in view of the above problems, and has as its object to provide a stable and highly reliable focus control even when the influence of groove crossing is large.

[0027]

In focus control using an astigmatism method or the like, when a beam spot of a light beam crosses an information track of an optical disk, the influence of groove crossing appears remarkably on a focus error signal. The quality of the error signal is degraded.

The effect of the groove crossing is not constant due to the combination of the individual variation of the optical pickup module and the individual variation of the optical disk.

The focus control is performed, and a tracking error signal (for example, phase difference tracking, disclosed in
-165737. Measures the magnitude of the focus error signal when the beam spot crosses the information track without tracking control to make the beam spot of the light beam scan on the information track of the optical disk based on (push-pull tracking). I do.
If the measured value exceeds a predetermined value, it is determined that the current combination of the optical pickup module and the optical disk has a large influence of groove crossing, and the focus control gain is reduced and the rotation speed of the disk motor is reduced.

By reducing the focus control gain, a large disturbance due to the influence of the groove crossing can be transmitted to the focus actuator with a smaller level than usual, and the focus actuator becomes violent due to the disturbance due to the groove crossing, and the focus control becomes unstable. And an effect of preventing the focus actuator from being damaged by an excessive focus drive signal.

At the same time, by lowering the rotation speed of the disk motor, it is possible to reduce the increase in the focus control residual due to the decrease in the focus control gain, and it is possible to perform stable focus control even at a low focus control gain. Become.

[0032]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, there is provided a rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined rotation speed, and a light beam directed toward the information carrier. Converging means for irradiating and converging light; light detecting means having a plurality of light receiving portions for detecting reflected light or transmitted light of the light beam from the information carrier; and a predetermined calculation of a plurality of light receiving portion outputs of the light detecting means. Focusing error detecting means for detecting a signal corresponding to the convergence state of the light beam, and a tracking state of the light beam to an information track by performing a predetermined calculation on outputs of a plurality of light receiving portions of the light detecting means. Tracking error detecting means for detecting a signal corresponding to the first and second moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; A second moving unit that moves the converging unit in a radial direction of the information carrier, and the first moving unit that is driven in response to a signal from the focus error detecting unit; Focus control means for controlling the light beam to converge, and tracking for controlling the light beam to scan the information track correctly by driving the second moving means in response to a signal from the tracking error detection means. Control means for detecting the magnitude of a signal synchronized with the information track crossing of the light beam appearing on the focus error detecting means when the tracking control means is deactivated and the focus control means alone is operated. Means when the signal detected by the groove traversing amount detecting means is larger than a predetermined level. By reducing the control gain of the control means to a predetermined value, and reducing the rotation speed of the information carrier by the rotation means to a predetermined value, the combination of an optical pickup module and an optical disk having a large influence of groove crossing can be realized. In addition, the focus control can be stably performed, and the focus actuator is prevented from being damaged.

According to a second aspect of the present invention, a rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined number of rotations, and irradiating and converging a light beam toward the information carrier. Converging means, light detecting means having a plurality of light receiving portions for detecting reflected light or transmitted light of the light beam from the information carrier, and performing a predetermined calculation on a plurality of light receiving portion outputs of the light detecting means, A focus error detecting means for detecting a signal corresponding to a convergence state of the light beam; and a signal corresponding to a tracking state of the light beam to an information track by performing a predetermined operation on a plurality of light receiving unit outputs of the light detecting means. Tracking error detecting means for detecting the position of the information carrier; first moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; A second moving means for moving the means in the radial direction of the information carrier, and the first moving means driven in response to a signal from the focus error detecting means, wherein the light beam is focused on the information carrier surface in a predetermined manner. Focus control means for controlling to be in a state, and driving the second moving means in accordance with a signal from the tracking error detection means,
Tracking control means for controlling the light beam to correctly scan on the information track; and information on the light beam appearing on the focus error detecting means when the tracking control means is deactivated and only the focus control means is operated. Groove crossing amount detecting means for detecting the magnitude of a signal synchronized with track crossing, wherein the signal detected by the groove crossing amount detecting means is a predetermined value when the focus control means operates and the tracking control means does not operate. After reducing the control gain of the focus control when the level is larger than the level and reducing the rotation speed of the rotation unit to a predetermined value,
By returning the control gain of the focus control means and the rotation speed of the rotation means to normal settings when the tracking control means is operating, focus control can be stably performed even with a combination of a head and an optical disk having a large influence of groove crossing, and Not only can the focus actuator be prevented from being damaged, but also the optical pickup module and the optical disk, which have a large influence of groove crossing, by returning the control gain and the rotation speed of the focus control to predetermined settings during tracking control. Even in the case of combination, there is an effect that the reproduction can be performed at the same data transfer rate as the combination having no influence of the groove crossing during the continuous data reproduction without the search operation.

According to a third aspect of the present invention, in the groove traversing amount detecting means, the magnitude of the signal synchronized with the track traversal of the light beam appearing in the focus error detecting means is determined by the absolute value of the output signal of the focus error detecting means. The detection is performed based on the integrated value of the values, and has an effect that erroneous detection due to disturbance appearing momentarily can be prevented.

According to a fourth aspect of the present invention, the groove traversing amount detecting means determines the magnitude of the signal synchronized with the track traversal of the light beam appearing in the focus error detecting means to the local maximum of the output signal of the focus error detecting means. The control system is configured to detect the average of the average value and the minimum value of the values, and to detect the groove crossing amount based on the amplitude obtained from the difference. Also has the effect that the groove crossing amount can be correctly detected.

According to a fifth aspect of the present invention, a rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined number of rotations, and irradiating and converging a light beam toward the information carrier. Converging means, light detecting means having a plurality of light receiving portions for detecting reflected light or transmitted light of the light beam from the information carrier, and performing a predetermined calculation on a plurality of light receiving portion outputs of the light detecting means, A focus error detecting means for detecting a signal corresponding to a convergence state of the light beam; and a signal corresponding to a tracking state of the light beam to an information track by performing a predetermined operation on a plurality of light receiving unit outputs of the light detecting means. Tracking error detecting means for detecting the position of the information carrier; first moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; A second moving means for moving the means in the radial direction of the information carrier, a gain adjusting means for adjusting an output signal of the tracking error detecting means to a predetermined level, and an output signal of the focus error detecting means. A focus calculating means for calculating an output signal; and a focus for driving the first moving means in accordance with a signal from the focus calculating means and controlling the light beam to be in a predetermined convergence state with respect to the information carrier surface. Control means, and tracking control means for driving the second moving means according to the signal of the tracking error detection means, and controlling the light beam to scan the information track correctly, A signal obtained by multiplying the focus error signal by the tracking error signal by a predetermined gain is added or subtracted, and based on the signal after the calculation, By performing focus control, it is possible to construct a focus control system that is less affected by groove crossing, and to achieve stable focus control without changing the rotation speed or focus control gain even in the case of a combination of a head and an optical disk that is significantly affected by groove crossing. And the damage of the focus actuator can be prevented.

According to a sixth aspect of the present invention, there is provided a rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined rotation speed, and irradiating and converging a light beam toward the information carrier. Converging means, light detecting means having a plurality of light receiving portions for detecting reflected light or transmitted light of the light beam from the information carrier, and performing a predetermined calculation on a plurality of light receiving portion outputs of the light detecting means, A focus error detecting means for detecting a signal corresponding to a convergence state of the light beam; and a signal corresponding to a tracking state of the light beam to an information track by performing a predetermined operation on a plurality of light receiving unit outputs of the light detecting means. Tracking error detecting means for detecting the position of the information carrier; first moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; A second moving means for moving the means in the radial direction of the information carrier, a gain adjusting means for adjusting an output signal of the tracking error detecting means to a predetermined level, and an output signal of the focus error detecting means. A focus calculating means for calculating an output signal; and a focus for driving the first moving means in accordance with a signal from the focus calculating means and controlling the light beam to be in a predetermined convergence state with respect to the information carrier surface. Control means, tracking control means for driving the second moving means in response to a signal from the tracking error detection means, and controlling the light beam to scan the information track correctly, and gain of the gain adjustment means. When the tracking control means is deactivated and only the focus control means is operated for setting, Are those having a groove crossing detecting means for detecting the magnitude of the signal synchronized with the light beam of the information track crossing appearing in Kasuera detecting means, based on the detected amount by the groove crossing detecting means,
The gain of the gain adjustment unit is adjusted so that the tracking error signal after the gain adjustment by the gain adjustment unit becomes equal to the groove crossing amount included in the focus error signal. By performing this gain adjustment, it is possible to obtain the signal of the focus calculation unit irrespective of the individual variation of the influence amount of the groove crossing.By performing the focus control based on the output signal of the focus unit, the gain of the gain adjustment unit is reduced. A focus control system that is less affected by the groove crossing can be constructed for a fixed system. Therefore, even in the case of a combination of a head and an optical disk having a great influence of the groove crossing, the focus control can be stably performed without changing the rotation speed and the focus control gain, and the damage of the focus actuator can be prevented. .

According to a seventh aspect of the present invention, there is provided a phase comparison means for comparing the phase of the first focus error signal which is the output signal of the focus error detection means with the phase of the output signal of the tracking error detection means. In the case of the same phase, the focus calculation means performs the subtraction processing, and in the case of the opposite phase, the focus calculation means performs the addition processing, thereby always reducing the focus error signal. This has the effect that an error signal can be reduced.

According to the invention described in claim 8 of the present invention, an information track composed of concentric or spiral concave and convex grooves is divided into predetermined areas, and the position of each divided block is indicated. A rotating means for rotating an information carrier having an address portion in which an address is recorded in a pit called a pit between blocks of an information track at a predetermined number of rotations, and a converging means for irradiating and converging a light beam toward the information carrier. A light detecting means having a plurality of light receiving portions for detecting the reflected light or transmitted light of the light beam from the information carrier; and Focus error detecting means for detecting a signal corresponding to the convergence state; and information of the light beam by performing a predetermined calculation on outputs of a plurality of light receiving portions of the light detecting means. Tracking error detecting means for detecting a signal corresponding to a tracking state on a rack; first moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; and A second moving means moving in the radial direction of the information carrier, and a noise signal on an output signal of the focus error detecting means appearing in synchronization with the light beam traversing the track;
Gain adjusting means for adjusting the output signal of the tracking error detecting means to a predetermined level; focus calculating means for calculating the output signal of the gain adjusting means on the output signal of the focus error detecting means; and signals of the focus calculating means Focus control means for driving the first moving means in accordance with the control signal so that the light beam is brought into a predetermined convergence state with respect to the information carrier surface, and the second control means in response to a signal from the tracking error detection means. The signal amplitude of the focus error detecting means when the light beam scans the address portion of the information carrier and the tracking control means for controlling the light beam to scan the information track correctly by driving the moving means. Address disturbance detecting means for detecting, wherein a detection signal of the address disturbance detecting means is at a predetermined level. When the value is larger, the control gain of the focus control means is reduced to a predetermined value, and the rotation speed of the information carrier by the rotation means is reduced to a predetermined value. If the signal amplitude of the focus error signal is larger than a predetermined level, the control gain of the focus control means is reduced and the rotation speed is set low, so that tracking can be performed even in the case of a combination of a head and an optical disk which is greatly affected by groove crossing. There is an effect that the focus control can be stably performed during the control and damage to the focus actuator can be prevented.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of focus control of an optical disk apparatus according to Embodiment 1 of the present invention. Members and portions similar to those in the related art are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 1, reference numeral 26 denotes a groove crossing determination unit which measures the magnitude of the focus error signal FE which has been A / D converted by the first A / D converter 24, and is internally set to a predetermined value. By comparing the magnitude with the specified value, it is determined whether or not the influence of the groove crossing is large. Reference numeral 40 denotes a microcomputer which checks whether or not the groove crossing determination unit 26 determines that the influence of groove crossing is large. Based on the result, the amplification factor of the first gain adjustment unit 28 and the control rotation speed of the disk motor control unit 31 are determined. Set.

The focus control operation of the optical disc device according to the first embodiment of the present invention configured as described above will be described below with reference to FIG. When the focus control is performed and the tracking control is not performed, in addition to the original focus error signal FE, the influence of the groove crossing when the light beam crosses the information track is included in the output signal of the second differential amplifier 21. Noise signal.

The amount of the noise signal generated is not constant due to manufacturing variations of the optical pickup module 4 and the type of the optical disk 36.

FIG. 11 shows this state. Groove crossing determination unit 2
Although the focus error signal measured at 6 is a digital signal, it is shown here as an analog signal. FIG. 11A shows a focus error signal in the case where the influence of the groove crossing is relatively small, and a relatively large group of pulses in the tracking control OFF state is noise at the time of groove crossing.
It is smaller than the specified value defined in. When the groove crossing determination unit 26 determines that the magnitude of the focus error signal FE is smaller than the specified value, the microcomputer 40 sets the first gain adjustment unit 28 to the normal gain. DSP3
Reference numeral 5 denotes a first gain adjustment unit 28 that performs gain adjustment based on a focus error signal at a normal amplification factor, and sends the gain to a focus drive circuit 32 via a phase compensation unit 29 and a D / A converter 30. And the focus actuator 10
Focuses the beam spot of the light beam on the optical disc 3
The objective lens 1 is placed on the optical disk 3 so as to match the information surface of the optical disk 3.
6 is controlled to move substantially vertically. At this time, no excessive current flows through the focus actuator 10, and stable focus control can be performed.

Next, the operation when the influence of the groove crossing is large will be described.

FIG. 11B shows a focus error signal in the case where the influence of the groove crossing is large. A large pulse group, which is noise at the time of groove crossing, exceeds the specified value determined by the groove crossing determination unit 26. In this case, if the first gain adjustment unit 28 keeps the normal amplification factor, the noise when crossing the groove is large, so that an excessive current flows through the focus actuator as shown in FIG. In addition, there is a risk that the focus actuator 10 may be damaged.

Therefore, as shown in FIG. 11B, when the focus error signal exceeds the specified value determined by the groove crossing determination unit 26, the microcomputer 40 receiving the determination result by the groove crossing determination unit 26 performs the first gain adjustment. The amplification factor of the section 28 is reduced. As a result, the focus actuator 1
The current flowing to 0 is reduced as shown in FIG. 11E. Thereby, damage to the focus actuator 10 can be prevented.

However, in order to reduce the excessive current flowing through the focus actuator 10, the first gain adjusting unit 2
By simply reducing the amplification factor of 8, the control residual due to the focus control increases as compared with the normal amplification factor, so that the stability of the focus control decreases. Therefore, when decreasing the amplification factor of the first gain adjustment unit 28, the microcomputer 40 simultaneously outputs a rotation speed reduction command to the disk motor control unit 31 and outputs the output of the disk motor control unit 31 and the disk motor drive circuit 33. Decrease the signal. As a result, the rotation speed of the optical disk 36 by the disk motor 34 is reduced, the increase in the residual focus control for the surface shake of the optical disk 36 is suppressed, and stable focus control can be performed.

The determination range of the groove traversing determination unit 26 is limited to focus error signals before and after the light beam spot crosses the information track when the focus control is performed and the tracking control is not performed. Highly accurate groove crossing determination is possible.

(Embodiment 2) FIG. 1 is a block diagram showing a configuration of focus control of an optical disk device according to Embodiment 2 of the present invention. Conventional technology and Embodiment 1
Members and portions similar to those described above are denoted by the same reference numerals, and description thereof is omitted.

As in the first embodiment, when the focus control is performed and the tracking control is not performed, the focus error signal FE which is the output signal of the second differential amplifier 21 is output.
The microcomputer 40 sends a determination start command from the microcomputer 40 to the groove crossing determination unit 26 in order to determine whether or not is greatly affected by groove crossing.

When the groove crossing determination section 26 determines that the magnitude of the focus error signal FE is smaller than the specified value, the microcomputer 40 sets the first gain adjustment section 28 at the normal amplification rate, and A normal rotation command is output to the disk motor control unit 31. The DSP 35 performs gain adjustment at the first gain adjustment unit 28 based on the focus error signal at a normal amplification rate, and the phase compensation unit 29
The focus actuator 10 is sent to the focus drive circuit 32 via the D / A converter 30, and the focus lens 10 moves the objective lens 1 with respect to the optical disc 36 so that the beam spot of the light beam is focused on the information surface of the optical disc 36. Is controlled to move vertically. At this time, no excessive current flows through the focus actuator 10, and stable focus control can be performed.

Next, the operation when the influence of the groove crossing is large will be described.

When the groove crossing determination section 26 determines that the magnitude of the focus error signal FE is larger than the specified value, the microcomputer 40 sets the first gain adjustment section 28 to be smaller than the normal amplification rate and controls the disk motor control. Part 31
Output deceleration command to

At this time, the DSP 35 performs gain adjustment at the first gain adjustment unit 28 with a smaller amplification factor based on the focus error signal.
The focus actuator 10 is sent to the focus drive circuit 32 via the D / A converter 30, and the focus lens 10 moves the objective lens 1 with respect to the optical disc 36 so that the beam spot of the light beam is focused on the information surface of the optical disc 36. Is controlled to move vertically. At this time, since the gain of the first gain adjustment unit 28 is smaller than usual, the FE signal after gain adjustment output from the first gain adjustment unit 28 becomes smaller than usual, and the focus actuator 1
An excessive current does not flow to 0, and stable focus control can be performed.

If the tracking control is not performed, the focus control becomes unstable because the light beam spot crosses the information track of the optical disk 36 and the focus error signal FE is affected by the groove crossing. Since the light beam spot always exists on the information track, the focus error signal is not affected by the groove crossing (FIG. 12). Therefore, when it is determined that the influence of the groove crossing is small, the DSP 35 directly starts the tracking control when the microcomputer 40 turns on the tracking control (not shown), but it is determined that the influence of the groove crossing is large. If the microcomputer 4
0 turns on the tracking control (not shown). At the same time, the microcomputer 40 returns the adjustment gain of the first gain adjustment unit 28 of the focus control to the normal gain, and the disk motor control unit 31 has the normal rotation speed. Sends a command to rotate the disk motor, and the DSP 35 performs tracking control with the same focus control gain and disk motor speed as when the influence of groove crossing is small (not shown).

Thus, even when the influence of groove crossing is large, it is possible to take in data without reducing the reproduction speed at the time of reproducing continuous data, and to prevent the focus actuator 10 from being damaged, while providing stable focus control. Becomes possible.

(Embodiment 3) FIG. 2 is a block diagram showing a configuration of focus control of an optical disk apparatus according to Embodiment 3 of the present invention. Members and portions similar to those of the prior art and the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 2, reference numeral 50 denotes an absolute value converter, which can easily handle the FE signal fluctuation amount as an AC component.
Convert to absolute value from reference value. Reference numeral 51 denotes an integration unit which integrates the FE signal whose absolute value has been converted by the absolute value conversion unit 50 for a certain period of time and outputs it.

The operation for determining the magnitude of the influence of the groove crossing amount will be described.

FE generated by second differential amplifier 21
The signal is converted into a digital signal by the first A / D converter 24 in the DSP 35 and becomes an input signal of the groove crossing determination unit 26. The digital signal converted by the first A / D converter 24 The FE signal of the signal (FIG. 2A) is converted into an absolute amount from the reference position by the absolute value converter 50 (FIG. 2).
b) Integrator 51 integrates for a fixed period of time and outputs (FIG. 2c).

The output signal of the integration section 51 indicates the amount of influence of the FE signal on the groove crossing. The larger the output signal, the greater the effect of the groove crossing.

As shown in FIG. 2C, the groove crossing determination unit 26 has a groove crossing determination value therein, and when the output signal of the integrating unit 51 exceeds the groove crossing determination value, the influence of groove crossing is large. The microcomputer 40 makes a judgment and notifies the microcomputer 40 of the judgment result. When the microcomputer 40 receives the determination result that the magnitude of the FE signal is larger than the groove crossing determination value from the groove crossing determination unit 26, the microcomputer 40 sets the first gain adjustment unit 28 to be smaller than the normal gain.

At this time, the DSP 35 outputs the FE signal to the first
The gain actuator 28 performs amplification at a smaller amplification factor than normal, and sends it to the focus drive circuit 32 via the phase compensator 29 and the D / A converter 30 so that the focus actuator 10 The objective lens 1 is controlled to move in a direction substantially perpendicular to the optical disc 36 so that the spot focus is adjusted to the information surface of the optical disc 36. At this time, since the gain of the first gain adjustment unit 28 is smaller than normal, the FE signal after the gain adjustment output from the first gain adjustment unit 28 becomes smaller than normal, and an excessive current flows through the focus actuator 10. There is no flow, and damage to the focus actuator 10 can be prevented.

However, in order to reduce an excessive current flowing through the focus actuator 10, the first gain adjusting unit 2
By simply reducing the amplification factor of 8, the control residual due to the focus control increases as compared with the normal amplification factor, so that the stability of the focus control decreases. Therefore, when decreasing the amplification factor of the first gain adjustment unit 28, the microcomputer 40 simultaneously outputs a rotation speed reduction command to the disk motor control unit 31 and outputs the output of the disk motor control unit 31 and the disk motor drive circuit 33. Decrease the signal. As a result, the rotation speed of the optical disk 36 by the disk motor 34 is reduced, the increase in the residual focus control for the surface shake of the optical disk 36 is suppressed, and stable focus control can be performed.

The operation in the case where the FE signal which is the output signal of the second differential amplifier 21 includes disturbance noise will be described with reference to FIGS.

In FIG. 2, if the FE signal converted into a digital signal by the first A / D converter 24 includes disturbance noise, which is a large pulse as shown in FIG. The signal converted into an absolute value at the time becomes an output signal in a state where disturbance noise is included as shown in FIG. 13B.

However, if the integration period is sufficiently long with respect to the frequency of the disturbance noise when the integration period is integrated by the integration unit 51, the output signal of the integration unit 51 is not affected by the disturbance noise as shown in FIG. 13C. It has the feature of outputting a signal. Thus, the groove traversing determination unit 26 can perform determination without being affected by disturbance noise that is a large pulse.

With the above-described processing for determining the groove crossing amount based on the output signal of the integrating section 51, even if a large pulse is generated in the FE signal due to disturbance noise or the like, the influence of the groove crossing is not immediately reduced without reducing the gain of the focus control. It is determined that the influence of the groove crossing is large when the mixing of the large pulse signal of the FE signal due to the above is continuous to some extent, so that it is possible to perform the groove crossing determination having an effect of preventing erroneous detection due to disturbance appearing momentarily. An optical disk device can be provided.

(Embodiment 4) FIG. 3 is a block diagram showing a configuration of focus control of an optical disk apparatus according to Embodiment 4 of the present invention. Members and portions similar to those of the prior art and the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 3, reference numeral 52 denotes an upper peak detecting unit.
The maximum value of the input FE signal is detected and output. A lower peak detector 53 detects and outputs a minimum value of the input FE signal. Numeral 54 denotes an amplitude calculating section for obtaining the amplitude of the FE signal by taking the output difference between the upper peak detecting section 52 and the lower peak detecting section 53.

The operation for determining the magnitude of the influence of the groove crossing amount will be described.

As shown in FIG. 3A, the second differential amplifier 2
1 is the first A / A signal in the DSP 35.
The FE signal of the digital signal converted by the first A / D converter 24 is converted into a digital signal by the D converter 24 and becomes an input signal of the groove crossing determination unit 26.
The signal is divided into two and becomes the input signals of the upper peak detector 52 and the lower peak detector 53, respectively.

The upper peak detector 52 generates a signal that follows the fluctuation of the upper peak of the FE signal, which is the input signal, as shown in FIG. 3B, and the lower peak detector 53 generates, as shown in FIG. A signal that follows the fluctuation of the lower peak of the FE signal that is the input signal is generated. The amplitude calculation unit 54 generates an amplitude of the FE signal by using an output signal of the upper peak detection unit 52 that is an upper peak value of the FE signal and an output signal of the lower peak detection unit 53 that is a lower peak value of the FE signal. Is an input signal, the difference between them is calculated, and as shown in FIG.
A signal indicating the amplitude of E is output.

The output signal indicating the amplitude of the FE indicates the control error of the focus control and the amount of influence of the FE signal crossing the groove. The larger the output signal, the greater the influence of the FE signal crossing the groove.

As shown in FIG. 3C, the groove crossing determination unit 26 has a groove crossing determination value therein, and when the output signal of the amplitude calculator 54 exceeds the groove crossing determination value, the influence of groove crossing is large. And notifies the microcomputer 40 of the determination result.

When the microcomputer 40 receives from the groove crossing determining section 26 a result of the determination that the influence of groove crossing contained in the FE signal is large, the microcomputer 40 sets the first gain adjusting section 28 to be smaller than the normal gain.

At this time, the DSP 35 amplifies the signal at a gain smaller than usual in the first gain adjuster 28 based on the FE signal, and focuses via the phase compensator 29 and the D / A converter 30. By sending the focus signal to the drive circuit 32, the focus actuator 10 is controlled to move the objective lens 1 in a direction substantially perpendicular to the optical disc 36 so that the beam spot of the light beam is focused on the information surface of the optical disc 36. At this time, the first gain adjustment unit 28
Is smaller than usual, the first gain adjustment unit 2
The FE signal after the gain adjustment output from 8 becomes smaller than usual, so that an excessive current does not flow through the focus actuator 10, and damage to the focus actuator 10 can be prevented.

However, in order to reduce the excessive current flowing through the focus actuator 10, the first gain adjustment unit 2
By simply reducing the amplification factor of 8, the control residual due to the focus control increases as compared with the normal amplification factor, so that the stability of the focus control decreases. Therefore, when decreasing the amplification factor of the first gain adjustment unit 28, the microcomputer 40 simultaneously outputs a rotation speed reduction command to the disk motor control unit 31 and outputs the output of the disk motor control unit 31 and the disk motor drive circuit 33. Decrease the signal. As a result, the rotation speed of the optical disk 36 by the disk motor 34 is reduced, the increase in the residual focus control for the surface shake of the optical disk 36 is suppressed, and stable focus control can be performed.

The operation in the case where the FE signal which is the output signal of the second differential amplifier 21 contains a large offset component will be described with reference to FIGS.

In FIG. 3, when the FE signal converted into a digital signal by the first A / D converter 24 contains a large offset component as shown in FIG. The output signal of the detection unit 53 is a signal affected by the offset component included in the FE signal as shown in FIG. 14B.

Here, as shown in FIG. 14B, when a judgment value is set for judging the magnitude of the influence of the groove crossing included in the FE signal by the output signal of the upper peak detector, when the influence of the groove crossing is small. However, it is erroneously determined that the influence of the groove crossing is large due to the influence of the offset.

Therefore, only the FE amplitude is extracted.

The upper peak detector 52 and the lower peak detector 53
Each of the output signals includes an offset component. However, the difference between the output signal of the upper peak detection unit and the output of the lower peak detection unit is calculated by the amplitude calculation unit 54, so that the offset components included in the respective output signals are included. The components cancel each other out, and the FE amplitude irrelevant to the offset component can be extracted. By setting a determination value as shown in FIG. 14C with respect to the output signal of the amplitude calculation unit 54, the difference in the offset component of the FE signal due to the individual variation and the change in the focus control residual during the reproduction cause the FE signal to change. Even in a control system in which the offset component fluctuates, the groove traversing determination unit 26 can make a determination that is not affected by the offset component. With this, when there is an offset component in the focus error signal, or even in a control system in which a stationary residual of focus control fluctuates relatively largely, a groove crossing determination having an operation of correctly detecting the groove crossing amount is performed. It is possible to provide an excellent optical disk device capable of performing such operations.

(Embodiment 5) FIG. 4 is a block diagram showing a configuration of focus control of an optical disk device according to Embodiment 5 of the present invention. Members and portions similar to those of the prior art and the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

Reference numeral 18 denotes a third adder for adding the outputs of the first I / V converter 12 and the third I / V converter 14. 1
Reference numeral 9 denotes a fourth adder, which adds the outputs of the second I / V converter 13 and the fourth I / V converter 15. 20 is a first differential amplifier, which is a push-pull tracking error signal pp
In order to generate TE, a differential signal between the output signal of the third adder 18 and the output signal of the fourth adder 19 is output.

The situation will be described with reference to FIG. Third
The output signal of the adder 18 is a signal indicating the total amount of received light detected by the divided light receiving units 3A and 3C of the photodetector shown in FIG. 10, and the output signal of the fourth adder 19 is the light It is a signal indicating the total amount of received light detected by the divided light receiving sections 3B and 3D of the detector.

The output signal of the first differential amplifier 20, which is the difference between the two, is the difference in the longitudinal direction of the information track in the divided light receiving section of the photodetector as shown in FIG. This is the signal ppTE.

A gain adjuster 23 in FIG. 4 amplifies the ppTE signal amplitude, which is the output signal of the first differential amplifier 20, at a predetermined fixed amplification factor. Reference numeral 22 denotes a focus computing unit, which is a ppT whose gain is adjusted as an output signal of the gain adjuster 23 from an FE signal which is an output signal of the second differential amplifier 21.
By subtracting the E signal, a focus error signal FE2 that is less affected by groove crossing is created. Reference numeral 25 denotes a second A / D converter, which converts a focus error signal FE2, which is an analog signal, which is less affected by groove crossing, into a digital signal that can be processed in the DSP 35.

The focus control operation of the optical disk apparatus according to the fifth embodiment of the present invention having the above-described configuration will be described below with reference to FIGS.

When focus control is performed and tracking control is not performed, the beam spot of the light beam
FIG. 15 shows a state when the information track on the optical disk 36 is crossed.

In FIG. 15, FIG. 15A shows the ppTE signal when the information track is traversed, and FIG. 15B shows the FE signal when the information track is traversed.

As shown in FIG. 15A, the ppTE signal indicates the reference voltage VREF when the beam spot of the light beam is located on the information track of the optical disc 36, and the difference from the reference voltage VREF increases as the beam spot deviates from the information track. Become.

On the other hand, the FE signal greatly affected by the groove crossing is shown in FIG.
As shown in FIG. 5b, the effect of groove crossing is synchronized with the change of the ppTE signal. Therefore, as a means for removing the influence of the groove crossing of the FE signal, it is possible to reduce the influence of the groove crossing by subtracting a signal obtained by amplifying the ppTE signal at a predetermined amplification rate from the FE signal.

Hereinafter, the processing will be described in detail.

The ppTE signal (FIG. 15A), which is the input signal of the gain adjuster 23 and is the output of the first differential amplifier, is amplified by the gain adjuster 23 at a predetermined fixed amplification factor and output.

Here, in the combination of the standard optical pickup module 4 and the standard optical disc 36, the predetermined fixed amplification factor is p amplified by this fixed amplification factor.
The pTE signal amplitude is determined in advance so as to correspond to or be slightly smaller than the influence amount of the groove crossing included in the amplitude of the FE signal (FIG. 15B) which is the output signal of the second differential amplifier 21.

From the FE signal, which is the output signal of the second differential amplifier 21, the amplified ppTE signal corresponding to the amount of influence of the groove crossing contained in the FE signal is subtracted by the focus calculator 22. Is performed, and the focus error signal (FE2 signal (FIG. 1)
Output from the focus calculator 22 as 5c)).

The DSP 35 does not perform focus control based on the FE signal, but performs control based on the FE2 signal.

The first gain adjuster 28 amplifies the FE2 signal amplitude and sends it to the focus drive circuit 32 via the phase compensator 29 and the D / A converter 30. Focus control is performed by moving the objective lens 1 in a direction substantially perpendicular to the optical disc 36 so that the beam spot of the beam is focused on the information surface of the optical disc 36.

At this time, since the FE2 signal hardly includes the influence of the groove crossing, the first gain adjustment unit 28
The output FE2 signal after the gain adjustment is sufficiently small, so that an excessive current does not flow through the focus actuator 10, and damage to the focus actuator 10 can be prevented.

By the above operation, even when the optical pickup module 4 and the optical disk 36 are combined and the influence of the crossing of the groove included in the FE signal is large, an excessive current does not flow through the focus actuator 10 and the focus actuator 10 While preventing damage, stable focus control becomes possible. In addition, since the disk motor 34 has no relation to the rotation speed of the disk motor 34, the disk motor control unit 31 only needs to control the disk motor 34 at a normal rotation speed even when the influence of the groove crossing is large. In addition to this, it is possible to provide an excellent optical disk device which is advantageous from the viewpoint of keeping the speed constant and from the viewpoint of power saving.

(Embodiment 6) FIG. 5 is a block diagram showing a configuration of focus control of an optical disk device according to Embodiment 6 of the present invention. Members and portions similar to those of the prior art and the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

Reference numeral 18 denotes a third adder for adding the outputs of the first I / V converter 12 and the third I / V converter 14. 1
Reference numeral 9 denotes a fourth adder, which adds the outputs of the second I / V converter 13 and the fourth I / V converter 15. 20 is a first differential amplifier, which is a push-pull tracking error signal pp
In order to generate TE, a differential signal between the output signal of the third adder 18 and the output signal of the fourth adder 19 is output.

This will be described with reference to FIG. Third
The output signal of the adder 18 is a signal indicating the total amount of received light detected by the divided light receiving portions 3A and 3C of the photodetector shown in FIG. 10, and the output signal of the fourth adder 19 is the light shown in FIG. It is a signal indicating the total amount of received light detected by the divided light receiving sections 3B and 3D of the detector.

The output signal of the first differential amplifier 20, which is the difference between them, is the difference in the longitudinal direction of the information track in the divided light receiving section of the photodetector as shown in FIG. This is the signal ppTE.

In FIG. 5, reference numeral 41 denotes a third A / D converter, which converts a ppTE signal, which is an analog signal, into a digital signal that can be processed in the DSP 35. Reference numeral 44 denotes a groove traversing amount calculating unit, which is a first A for the digitized ppTE signal amplitude which is the output signal amplitude of the third A / D converter 41.
FE which is an output signal of the / D converter 24
Calculate the signal amplitude ratio. Reference numeral 43 denotes a second gain adjustment unit, which is a pp digitized by the third A / D converter 41.
The TE signal is amplified at an amplification factor corresponding to the ratio specified by the groove crossing amount calculation unit 44. Reference numeral 42 denotes a focus calculation unit that subtracts the gain-adjusted ppTE signal, which is the output signal of the second gain adjustment unit 43, from the digitized FE signal that is the output signal of the first A / D converter. ,
A focus error signal FE2 that is less affected by groove crossing is generated.

The focus control operation of the optical disk device according to the sixth embodiment of the present invention configured as described above will be described below with reference to FIGS.

When focus control is performed and tracking control is not performed, the beam spot of the light beam
FIG. 15 shows a state when the information track on the optical disk 36 is crossed. In FIG. 15, FIG. 15A shows the ppTE signal when the information track is traversed, and FIG. 15B shows the FE signal when the information track is traversed.

As shown in FIG. 15A, the ppTE signal indicates the reference voltage VREF when the beam spot of the light beam is located on the information track of the optical disc 36, and the difference from the reference voltage VREF increases as the beam spot deviates from the information track. Become.

On the other hand, the FE signal greatly affected by the groove crossing is shown in FIG.
As shown in FIG. 5b, the effect of groove crossing is synchronized with the change of the ppTE signal. Therefore, as a means for removing the influence of the groove crossing of the FE signal, it is possible to reduce the influence of the groove crossing by subtracting a signal obtained by amplifying the ppTE signal at a predetermined amplification rate from the FE signal.

Hereinafter, the processing will be described in detail.

The FE signal generated by the second differential amplifier 21 and the pp signal generated by the first differential amplifier 20 shown in FIG.
The TE signal is converted into a digital signal by the first A / D converter 24 and the third A / D converter 41 in the DSP 35, respectively.

The FE signal (FIG. 15b) and the ppTE signal (FIG. 15a) converted into these digital signals are fetched as input signals to the groove crossing amount calculation unit 44, and the groove crossing amount calculation unit 44 It calculates how many times the amplitude is the ppTE amplitude, and outputs the calculation result as a set value of the second gain adjustment unit 43. The second gain adjuster 43 amplifies the digitized ppTE signal based on the set value.

For example, if the amplitude of the FE signal output from the first A / D converter 24 is 4 and the amplitude of the ppTE signal output from the third A / D converter 41 is 10, the groove crossing amount The calculation result of the calculation unit 44 is 4/10 = 0.4, and this value becomes the amplification factor of the second gain adjustment unit 43. Therefore the second
The amplitude of the output signal of the gain adjustment unit 43 is 10 (ppT
E) × 0.4 = 4, which matches the amplitude of the FE signal.

The second gain adjuster 43 amplifies the digitized ppTE signal based on the gain calculated by the groove crossing amount calculator 44.

The ppTE signal is supplied to the second gain adjuster 43
Since the signal has been converted into a signal substantially equal to the influence of the groove crossing included in the digitized FE signal which is the output signal of the first A / D converter 24, the focus calculation unit 42 By subtracting the amplified ppTE signal from the amplified FE signal, a focus error signal FE2 (FIG. 15c) having a small influence component due to groove crossing is generated.

The DSP 35 does not perform focus control based on the FE signal, but performs control based on the FE2 signal.

The first gain adjuster 28 amplifies the FE2 signal amplitude and sends the amplified signal to the focus drive circuit 32 via the phase compensator 29 and the D / A converter 30. Focus control is performed by moving the objective lens 1 in a direction substantially perpendicular to the optical disc 36 so that the beam spot of the beam is focused on the information surface of the optical disc 36.

At this time, since the FE2 signal hardly includes the influence of groove crossing, the first gain adjustment unit 28
The output FE2 signal after the gain adjustment is sufficiently small, so that an excessive current does not flow through the focus actuator 10, and damage to the focus actuator 10 can be prevented.

By the above operation, the influence of the groove crossing is removed from the FE signal due to the effect of the actual groove crossing.
Even when the influence of the groove crossing included in the FE signal is large due to the variation of the FE signal, an excessive current does not flow through the focus actuator 10 and the damage to the focus actuator 10 is prevented, and the stable focus control can be performed. Also,
Since it is irrelevant to the rotation speed of the disk motor 34, the disk motor control unit 31 only needs to control the disk motor 34 at a normal rotation speed even in a state where the influence of the groove crossing is large, which is advantageous for high-speed playback. In addition, it is possible to provide an excellent optical disk device that is advantageous in terms of power saving in that the speed is kept constant.

(Embodiment 7) FIG. 6 is a block diagram showing a configuration of focus control of an optical disk apparatus according to Embodiment 7 of the present invention. Conventional technology and Embodiment 6
Members and portions similar to those described above are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 3 denotes a first light receiving portion inside the optical pickup module 4, which receives the reflected light of the light beam irradiated on the optical disk 36 again through the objective lens 1 and receives the reflected light for processing by an electric circuit. The optical disk 3 is made of a photodetector that generates a current according to the amount of the light beam.
6 is supported. 45 is an optical pickup module 4
The internal second light receiving unit receives the reflected light of the light beam irradiated onto the optical disk 36 again through the objective lens 1 and outputs a current corresponding to the amount of the received light beam for processing by the electric circuit. The first light receiving unit 3 of the optical disk 36 corresponds to the optical disk 36 which is made of a photodetector for generating light. 40 is a microcomputer,
The user selects whether to use the first light receiving unit 3 or the second light receiving unit 45 in the optical pickup module 4 according to the optical disc 36 to be mounted. Reference numeral 46 denotes a second focus operation unit which converts a gain-adjusted ppTE signal which is an output signal of the second gain adjustment unit 43 from a digitized FE signal which is an output signal of the first A / D converter 24. By performing the subtraction or the addition, the focus error signal FE2 having little influence of the groove crossing is generated. The selection between addition and subtraction is determined depending on whether the microcomputer 40 selects the first light receiving section 3 or the second light receiving section 45, and the light receiving section in which the polarities of the FE signal and the ppTE signal are the same. The subtraction processing is selected for the light receiving section, and the addition processing is selected for the light receiving sections having different polarities.

The focus control operation of the optical disk device according to the seventh embodiment of the present invention configured as described above will be described below with reference to FIGS.

FIG. 15 shows a state where the optical pickup module 4 of FIG. 6 crosses the information track on the optical disk 36 of FIG. 6 when the focus control is performed and the tracking control is not performed. 15A and 15B show a ppTE signal when the information track is traversed and an FE signal when the information track is traversed when the first light receiving unit in FIG. 6 is selected, respectively. FIGS. 15D and 15E respectively show FIGS. 7 shows a ppTE signal when the information track is traversed and an FE signal when the information track is traversed when the second light receiving unit in FIG. 6 is selected.

As shown in FIGS. 15A and 15D, ppT
When the optical pickup module 4 shown in FIG. 6 is positioned on the information track of the optical disc 36, the E signal indicates the reference voltage V.
REF, and the reference voltage V
The difference from REF increases.

On the other hand, when the influence of the groove crossing on the FE signal is large, as shown in FIGS. 15B and 15E, the effect of the groove crossing appearing on the FE signal is synchronized with the change of the ppTE signal. Therefore, by subtracting or adding a signal obtained by amplifying the ppTE signal at a predetermined amplification rate from the FE signal as a means for removing the effect of the FE signal crossing the groove,
It is possible to reduce the effects of groove crossing.

The processing will be described in detail below.

The FE signal generated by the second differential amplifier 21 and the pp signal generated by the first differential amplifier 20 in FIG.
The TE signal is converted into a digital signal by the first A / D converter 24 and the third A / D converter 41 in the DSP 35, respectively.

The FE signal (FIGS. 15B and 15E) converted into these digital signals and the ppTE signal (FIG. 15A and FIG.
FIG. 15D) is fetched as an input signal of the groove crossing amount calculating section 44, and the groove crossing amount calculating section 44 sets the FE signal amplitude to ppT
The number of times the E amplitude is calculated, and the calculation result is output as a set value of the second gain adjustment unit 43. The second gain adjuster 43 converts the ppTE digitized based on the set value.
Amplify the signal.

For example, when the amplitude of the FE signal output from the first A / D converter 24 is 4 and the amplitude of the ppTE signal output from the third A / D converter 41 is 10, the groove crossing amount The calculation result of the calculation unit 44 is 4/10 = 0.4, and this value becomes the amplification factor of the second gain adjustment unit 43. Therefore the second
The amplitude of the output signal of the gain adjustment unit 43 is 10 (ppT
E) × 0.4 = 4, which matches the amplitude of the FE signal.

The ppTE signal is supplied to the second gain adjuster 43
Since the signal is converted into a signal substantially equal to the influence of the groove crossing included in the digitized FE signal which is the output signal of the third A / D converter 41, the second focus calculation unit 46
Are the FE signal digitized according to the light receiving unit selected by the microcomputer 40 and the amplified ppTE
If the signals are light receiving units having the same polarity, the amplified ppTE signal is subtracted from the FE signal (FIG. 15c). If the signals are light receiving units having different polarities, the ppT signal amplified to the FE signal is used.
By adding the E signal (FIG. 15F), the focus error signal FE2 (FIG. 15
c, FIG. 15f) is generated.

The DSP 35 does not perform focus control based on the FE signal, but performs control based on the FE2 signal.

The amplitude of the FE2 signal is amplified by the first gain adjusting section 28, and the amplified signal is sent to the focus driving circuit 32 via the phase compensating section 29 and the D / A converter 30. Focus control is performed by moving the objective lens 1 in a direction substantially perpendicular to the optical disc 36 so that the beam spot of the beam is focused on the information surface of the optical disc 36.

At this time, since the FE2 signal hardly includes the influence of crossing the groove, the first gain adjustment unit 28
The output FE2 signal after the gain adjustment is sufficiently small, so that an excessive current does not flow through the focus actuator 10, and damage to the focus actuator 10 can be prevented.

By the above operation, the influence of the groove crossing is removed from the FE signal due to the effect of the actual groove crossing.
When the influence of the groove crossing included in the FE signal is large due to the variation of the FE signal, the focus actuator 10 is excessively large even when two or more light receiving units are provided and the polarity of the ppTE signal generated from each light receiving unit is opposite. While no current flows, damage to the focus actuator 10 is prevented, and stable focus control is possible. In addition, since the disk motor control unit 31 has no influence on the rotation speed of the disk motor 34, the disk motor control unit 31 may control the disk motor 34 at a normal rotation speed even in a state where the influence of the groove crossing is large.
It is possible to provide an excellent optical disk device which is advantageous for high-speed playback and which is advantageous in terms of power saving in terms of keeping the speed constant.

(Embodiment 8) An optical disk mounted on an optical disk device according to Embodiment 8 of the present invention is an optical disk 36b having a RAM area shown in FIG.
As shown in FIG. 2, the data area is composed of a user data area 109 and an address area 110. In the user data area, signals are recorded due to the difference in crystal state of the phase change film. When the beam spot of the light beam is located on the address area 110, a large disturbance component (influence of groove crossing) may be included in the FE signal, which is a focus error signal. This causes control to become unstable.

FIG. 7 is a block diagram showing a configuration of focus control of an optical disk device according to Embodiment 8 of the present invention. Members and portions similar to those of the prior art and the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

37 is a fifth adder for the first to fourth I / Vs
It outputs a signal AS, which is the sum of the outputs of the converters and indicates the total amount of received light detected by the photodetector shown in FIG. 38 is the fourth
The A / D converter converts the total received light amount signal AS, which is an analog signal, detected by the photodetector into a digital signal that can be processed in the DSP 35. Reference numeral 39 denotes an address disturbance detection unit which determines whether the beam spot of the light beam passes through the address area 110 of the optical disk 36b during tracking control by comparing the amount of influence of groove crossing included in the FE signal with a predetermined value. I do.

Whether the beam spot of the light beam is located on the address area 110 where a disturbance component occurs in the FE signal is detected from the magnitude of the AS signal.

A microcomputer 40 sets the amplification factor of the first gain adjustment unit 28 and the target disk motor rotation speed setting of the disk motor control unit based on the detection result of the address disturbance detection unit 39.

The focus control operation of the optical disk device according to the eighth embodiment of the present invention having the above-described configuration will be described below with reference to FIGS. 7, 9, and 16.

As shown in FIG. 9B, an information track (land track 106) adjacent to the pit 101 of the address area 110 used for a generally recordable optical disk (for example, PD or DVD-RAM) is used. , Groove tracks 107) (FIG. 9)
When reproducing the optical disc 36b of (b)), when the beam spot of the light beam passes over the address area 110, the influence of the groove crossing on the focus error signal may occur. When the influence of the groove crossing is large, the focus control becomes unstable. Therefore, this embodiment is effective in such a state.

FIG. 16 shows a state where the beam spot of the light beam passes over the address area 110 on the optical disk 36 in FIG. 7 during the tracking control. In FIG. 16, FIG. 16a shows an FE signal during reproduction of a recordable disc, and FIG. 16b shows an AS signal.

FIG. 16A shows an address area 110 (FIG. 9).
(B)) This is an FE signal at the time of passage, and is greatly affected by crossing the groove.

At this time, as shown in FIG. 16, the signal AS signal obtained by adding the total light amount detected by the first light receiving section 3 inside the optical pickup module 4 is small.
By detecting that the AS signal falls below a predetermined amount, F
Address area 1 where E signal is greatly affected by groove crossing
10 can be detected.

Hereinafter, the processing will be described in detail.

When the tracking control is being performed, the fifth
Adder 37 performs addition of the output signals of the first adder 16 and the adder 17 of Ta-a-ai 2 to obtain the sum signal of all the divided light-receiving units of the photodetector as shown in FIG. That is, the first light receiving unit 3 inside the optical pickup module 4
An AS signal is generated by adding the total amount of reflected light from the disk 36 detected by the photodetector.

The AS signal is converted to a digital signal by the fourth A / D converter 38 so that the DSP 35 can perform the operation, and then output to the address disturbance detection unit 39.

The address disturbance detecting section 39 performs the first A / D
The FE signal and the AS signal digitized by the converter 24 and the fourth A / D converter 38, respectively, are fetched, and as shown in FIG. When the signal falls below the address detection level which is a predetermined value, it is determined that the influence of the groove crossing included in the FE signal in the address area is large, and the result is output to the microcomputer 40.

In the tracking control state, the microcomputer 40 receives from the address disturbance detecting section 39 a result indicating that the influence of the groove crossing included in the FE signal in the address area is large, the first gain adjusting section 28.
Is reduced from the normal state to a predetermined gain, and the disk motor target rotation speed of the disk motor control unit 31 is set to a predetermined value smaller than the normal state.

Here, when the detection result of the address disturbance detection section 39 determines that the influence of the groove crossing included in the FE signal in the address area is small, the first gain adjustment section 28 and the disk motor control section Numerals 31 respectively maintain the current amplification factor and the target rotation speed of the disk motor.

By the above operation, focus control is normally performed by the same operation as the conventional technology. However, the influence amount of the groove traversing amount included in the FE signal in the address area is determined by the address disturbance detecting unit 39 to the specified value. When it is determined that the above is the case, the focus error signal FE is
8, the gain is adjusted at a lower amplification factor than usual, and the phase compensator 29 performs a phase compensation process, and the D / A converter 3
At 0, an analog drive signal is generated. A drive voltage is applied to the focus actuator 10 from the focus drive circuit 32 based on the analog drive signal. As a result of the first gain adjustment unit 28 adjusting the gain at a lower amplification factor than normal, an excessive current Does not flow, preventing damage to the focus actuator 10 and enabling stable focus control.

However, in order to reduce an excessive current flowing through the focus actuator 10, the first gain adjuster 2
By simply reducing the amplification factor of 8, the control residual due to the focus control increases as compared with the normal amplification factor, so that the stability of the focus control decreases. Therefore, when decreasing the amplification factor of the first gain adjustment unit 28, the microcomputer 40 simultaneously outputs a rotation speed reduction command to the disk motor control unit 31 and outputs the output of the disk motor control unit 31 and the disk motor drive circuit 33. By lowering the signal,
It is possible to provide an excellent optical disk device that can reduce the rotational speed of the optical disk by the disk motor, suppress an increase in residual focus control with respect to surface deviation of the optical disk, and perform stable focus control. it can.

[0156]

According to the present invention as described above,
Prevents burnout of the focus actuator due to excessive current due to the effect of groove crossing, and reduces the influence of disturbance due to the effect of groove crossing. Can be improved. As a result, it is possible to provide a highly reliable optical disk device that is compatible with variations in the accuracy of the optical pickup and various types of disks.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an optical disk device according to Embodiments 1 and 2 of the present invention.

FIG. 2 is a diagram showing a configuration of an optical disk device according to a third embodiment of the present invention;

FIG. 3 is a diagram showing a configuration of an optical disk device according to a fourth embodiment of the present invention;

FIG. 4 is a diagram showing a configuration of an optical disk device according to a fifth embodiment of the present invention;

FIG. 5 is a diagram showing a configuration of an optical disc device according to a sixth embodiment of the present invention;

FIG. 6 is a diagram showing a configuration of an optical disk device according to a seventh embodiment of the present invention;

FIG. 7 is a diagram showing a configuration of an optical disk device according to an eighth embodiment of the present invention;

FIG. 8 is a schematic diagram (a perspective view and a sectional view) of a ROM disk used in the present invention.

FIG. 9 is a schematic diagram of a RAM disk used in the present invention.

FIG. 10 is a diagram showing division of a light receiving section of a photodetector used in the present invention.

FIG. 11 is a diagram for explaining an FE signal in a case where the FE signal is affected by groove crossing in the first embodiment of the present invention;

FIG. 12 is a diagram for explaining the influence of groove crossing on an FE signal when tracking control is performed in the second embodiment of the present invention.

FIG. 13 is a diagram for explaining an FE signal in a case where the FE signal is affected by crossing a groove according to the third embodiment of the present invention;

FIG. 14 is a diagram for explaining an FE signal in a case where the FE signal is affected by crossing a groove according to the fourth embodiment of the present invention;

FIG. 15 is a diagram for explaining a push-pull tracking error signal, a focus error signal, and a newly created FE signal which is not affected by groove crossing in the fifth, sixth, and seventh embodiments of the present invention.

FIG. 16 is a diagram for explaining a relationship between an FE signal and an AS signal when a light beam crosses an information track on a recordable optical disc when tracking control is performed in the eighth embodiment of the present invention.

FIG. 17 is a diagram showing a configuration of focus control of a conventional optical disc device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Laser part 3 First light receiving part 4 Optical pickup module 10 Focus actuator 11 Transfer stand 12 First I / V converter 13 Second I / V converter 14 Third I / V converter 15 Fourth I / V converter 16 First adder 17 Second adder 18 Third adder 19 Fourth adder 20 First differential amplifier 21 Second differential amplifier 22 Focus calculator Reference Signs List 23 Gain adjuster 24 First A / D converter 25 Second A / D converter 26 Groove crossing determination unit 28 First gain adjuster 29 Phase compensation unit 30 D / A converter 31 Disk motor control unit 32 Focus drive circuit 33 Disk motor drive circuit 34 Disk motor 35 DSP 36 Optical disk 37 Fifth adder 38 Fourth A / D converter 39 Address disturbance detector 40 My Computer 41 third A / D converter 42 focus operation unit 43 second gain adjustment unit 44 groove crossing amount operation unit 45 second light receiving unit 46 second focus operation unit 50 absolute value conversion unit 51 integration unit 52 Upper peak detector 53 Lower peak detector 54 Amplitude calculator 100 Base material 101 Pits 102 Reflective film 103 Protective film 104 Information track 105 ROM area 106 Land track 107 Groove track 108 Information track

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirodori Ishibashi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Katsuya Watanabe 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 5D118 AA24 AA28 BA01 BB02 CA02 CD02 CD03

Claims (8)

[Claims] 1. A rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined number of revolutions, a converging means for irradiating and converging a light beam onto the information carrier, and an information carrier for the light beam. Light detection means having a plurality of light receiving portions for detecting reflected light or transmitted light from
Focus error detection means for detecting a signal corresponding to the convergence state of the light beam by performing a predetermined operation on the outputs of the plurality of light receiving sections of the light detecting means, A tracking error detecting means for detecting a signal corresponding to a tracking state of the light beam on the information track by performing an operation, and a moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier. (1) moving means, a second moving means for moving the converging means in the radial direction of the information carrier, and the first moving means in response to a signal from the focus error detecting means, wherein the light beam A focus control means for controlling a predetermined convergence state with respect to the carrier surface; and a second movement means for driving the second movement means in accordance with a signal from the tracking error detection means. And tracking control means for the light beam is controlled so as to correctly scan over the information track,
A groove traversing amount detecting means for detecting a magnitude of a signal synchronized with traversing the information track of the light beam appearing in the focus error detecting means when the tracking control means is deactivated and only the focus controlling means is operated. When the signal detected by the groove traversing amount detecting means is larger than a predetermined level, the control gain of the focus control means is reduced to a predetermined value, and the rotation speed of the information carrier by the rotating means is reduced to a predetermined value. An optical disc device characterized by the above-mentioned. 2. A control gain for focus control is reduced when a signal detected by a groove traversing amount detecting means is greater than a predetermined level when the focus control means is operating and the tracking control means is not operating, and the rotational speed of the rotating means is reduced. 2. The optical disc apparatus according to claim 1, wherein after the tracking control means is operated, the control gain of the focus control means and the rotation speed of the rotation means are returned to a normal setting. 3. The groove traversing amount detecting means detects the magnitude of a signal synchronized with the track traversal of the light beam appearing in the focus error detecting means based on an integral value of an absolute value of an output signal of the focus error detecting means. 2. The optical disk device according to claim 1, wherein the optical disk device is configured as described above. 4. The groove traversing amount detecting means determines the magnitude of a signal synchronized with the track traversal of the light beam appearing in the focus error detecting means by calculating the average of the maximum value and the minimum value of the output signal of the focus error detecting means. 2. The optical disk apparatus according to claim 1, wherein the optical disk apparatus is configured to detect the groove traversing amount based on the detected amplitude and the amplitude obtained from the difference. 5. A rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined number of revolutions, a converging means for irradiating and converging a light beam on the information carrier, and an information carrier for the light beam. Light detection means having a plurality of light receiving portions for detecting reflected light or transmitted light from
Focus error detection means for detecting a signal corresponding to the convergence state of the light beam by performing a predetermined operation on the outputs of the plurality of light receiving sections of the light detecting means, A tracking error detecting means for detecting a signal corresponding to a tracking state of the light beam on the information track by performing an operation, and a moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier. 1 moving means, a second moving means for moving the convergence means in a radial direction of the information carrier, a gain adjusting means for adjusting an output signal of the tracking error detecting means to a predetermined level, and a focus error detecting means. A focus calculating means for calculating an output signal of the gain adjusting means on an output signal; and the first calculating means in response to the signal of the focus calculating means. Focus control means for driving a moving means and controlling the light beam to be in a predetermined convergence state with respect to the information carrier surface, and driving the second moving means in accordance with a signal of the tracking error detecting means, An optical disc device comprising: a tracking control unit for controlling the light beam to scan the information track correctly. 6. A rotating means for rotating an information carrier having a spiral or concentric information track at a predetermined number of revolutions, a converging means for irradiating and converging a light beam onto the information carrier, and an information carrier for the light beam. Light detection means having a plurality of light receiving portions for detecting reflected light or transmitted light from
Focus error detection means for detecting a signal corresponding to the convergence state of the light beam by performing a predetermined operation on the outputs of the plurality of light receiving sections of the light detecting means, A tracking error detecting means for detecting a signal corresponding to a tracking state of the light beam on the information track by performing an operation, and a moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier. 1 moving means, a second moving means for moving the convergence means in a radial direction of the information carrier, a gain adjusting means for adjusting an output signal of the tracking error detecting means to a predetermined level, and a focus error detecting means. A focus calculating means for calculating an output signal of the gain adjusting means on an output signal; and the first calculating means in response to the signal of the focus calculating means. Focus control means for driving a moving means and controlling the light beam to be in a predetermined convergence state with respect to the information carrier surface, and driving the second moving means in accordance with a signal of the tracking error detecting means, Tracking control means for controlling the light beam to correctly scan on the information track; and the tracking control means inactive for setting the gain of the gain adjustment means and the focus when the focus control means alone is operated. A groove traversing amount detecting means for detecting a magnitude of a signal synchronized with the information track traversing of the light beam appearing in the error detecting means, and setting a gain of the gain adjusting means based on the amount detected by the groove traversing amount detecting means; An optical disc device characterized by the above-mentioned. 7. A phase comparison means for comparing a phase of a first focus error signal, which is an output signal of the focus error detection means, with a phase of an output signal of the tracking error detection means. 7. The optical disk device according to claim 5, wherein the focus calculation means performs an addition process when the phase is opposite. 8. An information track composed of concentric or spiral grooves, and an information track are divided into predetermined areas, and an address indicating the position of each divided block is assigned between each block of the information track. A rotating means for rotating an information carrier having an address portion recorded in a pit called a pit at a predetermined number of rotations; a converging means for irradiating and converging a light beam toward the information carrier; and a converging means for transmitting the light beam from the information carrier. A light detecting means having a plurality of light receiving portions for detecting reflected light or transmitted light, and a signal corresponding to the convergence state of the light beam is detected by performing a predetermined operation on outputs of the plurality of light receiving portions of the light detecting means A tracking state of the light beam on an information track by performing a predetermined calculation on outputs of a plurality of light receiving sections of the focus error detecting means and the light detecting means; Tracking error detecting means for detecting a corresponding signal; first moving means for moving the convergence means in a direction substantially perpendicular to the information surface of the information carrier; and Second to move
Moving means, and gain adjustment for adjusting the output signal of the tracking error detecting means to a predetermined level in order to reduce a noise signal on the output signal of the focus error detecting means which appears in synchronization with the light beam traversing the track. Means for calculating the output signal of the gain adjusting means to the output signal of the focus error detecting means, and the first signal processing means in response to the signal of the focus calculating means.
Focus control means for controlling the light beam to be in a predetermined convergence state with respect to the information carrier surface; and driving the second movement means in response to a signal from the tracking error detection means. Tracking control means for controlling the light beam to scan the information track correctly; and address disturbance detection means for detecting a signal amplitude of the focus error detection means when the light beam scans the address portion of the information carrier. Wherein the control gain of the focus control means is reduced to a predetermined value when the detection signal of the address disturbance detection means is higher than a predetermined level, and the rotation speed of the information carrier by the rotation means is reduced to a predetermined value. An optical disc device characterized by performing: