JPH0778349A - Tracking control device for optical disk reproducing device - Google Patents

Abstract

PURPOSE:To control a tracking servo in an appropriate balanced state by performing feedback to a balance adjusting means until an output signal of an A/D converter is contained within the prescribed range. CONSTITUTION:At the time of controlling tracking of a disk, the disk is rotated, each reflected light of each auxiliary beam is detected (5, 6), each detected signal is supplied to a balance adjusting circuit 7. Initial data set in a memory 18 is supplied to the circuit 7 through a D/A converter 19. A CPU 17 judges whether a signal from an A/D converter 16 is contained within the prescribed range, increases or decreases the initial data of the memory 18 so that a signal from the converter 16 is contained within the prescribed range and makes the memory 18 store it. After that, when the signal from the converter 16 is contained within the prescribed range based on the judgement of the CPU 17, a switch 9 is turned on, a tracking driving circuit 10 is turned on and a tracking servo is driven and controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking control device for an optical disk reproducing apparatus for reproducing an information signal recorded on a disk by a light beam.

[0002]

2. Description of the Related Art In an optical disk reproducing apparatus, a focus servo and a tracking servo are necessary in order to accurately read an information signal recorded on the disk.
The tracking servo controls the light beam so that it does not deviate from the center of the track.By detecting the deviation from the center of the track, that is, tracking error, and moving the entire pickup based on this detection signal, the light beam Is moved in the disk radial direction to control the tracking error to zero.

A conventional tracking control device for this purpose, as shown in FIG. 5 which is an explanatory view of the present invention, has a main beam 1 for reading an information signal of a disc and a first auxiliary beam 2 for detecting a tracking error. The second auxiliary beam 3 is provided so that the first auxiliary beam 2 and the second auxiliary beam 3 are symmetrical with respect to the direction along the pit track 4 about the main beam 1 and the direction orthogonal thereto. A light beam is incident. Also, these first
The reflected light from the auxiliary beam 2 and the second auxiliary beam 3 is, as shown in FIG. 6, a first photodetector 51 and a second photodetector 52.
Detected by and respectively, and the detected current signal Ie
And the current signal If are supplied to the voltage signal Ve and the voltage signal V by the I / V converter 53 and the I / V converter 54, respectively.
After being converted to f, the voltage signal Ve and the voltage signal Vf become the tracking error voltage Ve-Vf by the subtractor 55.

More specifically, when the main beam 1 shown in FIG. 5 exists at the center of the pit track 4, the current signal Ie of the first photodetector 51 and the current signal If of the second photodetector 52 are Becomes equal, and the tracking error voltage Ve −
Vf becomes zero. The main beam 1 is the pit track 4
Of the tracking error voltage Ve due to the difference between the current signal Ie of the first photodetector 51 and the current signal If of the second photodetector 52 depending on the magnitude of the deviation.
-Vf becomes nonzero. The non-zero tracking error voltage Ve-Vf is given to the tracking control circuit 57 via the switch 56, whereby the main beam 1 and the first auxiliary beam 2 are supplied in accordance with the magnitude of the tracking error voltage Ve-Vf. Second auxiliary beam 3
And are controlled by the tracking coil 57 in the radial direction of the disk.

By the way, in the above tracking control device, the dispersion of the diffraction grating that divides the main beam 1 of the pickup into the first auxiliary beam 2 and the second auxiliary beam 3, the first photodetector 51 and the second photodetector. Even if the main beam 1 is located at the center of the pit track 4, the tracking error voltage Ve-Vf may not be zero due to variations in the device 52.

As a conventional coping method in this case, in order to balance the signal Ve and the signal Vf, a semi-fixed resistor 59 is mounted and the disk is rotated with the switch 56 in the OFF state. When the beam 1 exists at the center of the pit track 4, the semi-fixed resistor 59 is adjusted at the time of certifying the product so that the voltage Ve-Vf output from the subtractor 55 becomes zero.

[0007]

However, in the tracking control device of the conventional optical disk reproducing device described above,
Considering the increase in the number of man-hours in today's production process and variations in the reflected light of various discs, the main beam 1 becomes the pit track 4
Tracking error voltage Ve
There is a problem that -Vf does not become zero and it is rather difficult to stabilize the tracking servo. That is,
Generally, there is a variation every time the disc is started, and if it is fixed uniformly by the semi-fixed resistor 59, the regular reference position, that is, the main beam 1 exists at the center of the pit track 4. Since the control from the position becomes impossible, the balance adjustment becomes rather complicated.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to always keep a proper tracking error voltage, including variations in diffraction grating and variations in reflected light for each disc. An object of the present invention is to provide a tracking control device of an optical disk reproducing device that can control tracking servo in a state.

[0009]

According to a first aspect of the present invention, there is provided a tracking control device for an optical disk reproducing apparatus, which comprises: a main beam for reading an information signal recorded on a disk; A first auxiliary beam and a second auxiliary beam used for error detection, a first photodetector and a second photodetector that detect reflected light of each of the first auxiliary beam and the second auxiliary beam, and the first light An optical disc reproducing apparatus including a first differential amplifier that subtracts each signal generated by a detector and a second photodetector, and a tracking drive circuit that drives a tracking servo based on the output of the first differential amplifier. In the tracking control device, a positive-side detector that detects the output signal of the first differential amplifier to the positive side, and a negative-side detector that detects the output signal of the first differential amplifier to the negative side A second differential amplifier that subtracts the two signals of the positive-side detector and the negative-side detector, an A / D converter that converts an analog signal of the second differential amplifier into a digital signal, and the above A / D A judging means for judging whether or not the digital signal from the converter is within a predetermined range, a storing means for storing predetermined initial data, and an A / based on the judgment of the judging means.
Increase / decrease control means for increasing / decreasing the initial data of the storage means so that the digital signal from the D converter falls within a predetermined range and storing the same in the storage means, and D for converting the increase / decrease data stored in the storage means into an analog signal. / A converter and the above D / A
Balance adjusting means for adjusting the balance of the analog signals of the first photodetector and the second photodetector based on the analog conversion data in the converter and outputting to the first differential amplifier.
The switch for turning on / off the drive of the tracking servo and the switch for turning the switch on when the digital signal from the A / D converter is within a predetermined range based on the judgment of the judging means.
An ON control means for setting to N is provided.

According to a second aspect of the present invention, there is provided a tracking control device for an optical disc reproducing apparatus, wherein the tracking control device for the optical disc reproducing device according to the first aspect stores the storage means every time the disc is rotated. The execution control means for executing the storage of the increase / decrease data and the median value setting means for setting the initial data to the median value within the predetermined range are provided.

According to a third aspect of the present invention, there is provided a tracking control device for an optical disc reproducing apparatus, wherein the initial data after power-on is set to the tracking control device for an optical disc reproducing apparatus according to the first aspect. Provided are a median value setting means for setting the median value within a predetermined range, and an increase / decrease data holding means for setting the increase / decrease data stored in the storage means each time the disk is started to the hold data at the previous disk startup. It is characterized by being.

[0012]

According to the structure of claim 1, when the tracking control of the disk is performed, first, the switch is turned off to rotate the disk, and the reflected light of each of the first auxiliary beam and the second auxiliary beam is detected. The respective signals generated by the first photodetector and the second photodetector are input to the balance adjustment circuit.

In parallel with this balance adjustment circuit, predetermined initial data preset and input to the storage means is input to D /
It is converted into an analog signal by the A converter and input. The initial data is set so that 0 V is applied to the D / A converter at first, and when there is no difference in the magnitude of each signal generated by the first photodetector and the second photodetector, Since the balance adjustment circuit outputs the signals generated by the first photodetector and the second photodetector to the first differential amplifier as they are, they are balanced.

Here, for example, the output from the first differential amplifier is not 0V due to variations in the diffraction grating and the disks.

At this time, the output signal from the first differential amplifier is detected by the positive-side detector and the negative-side detector into two types of DC voltage, the positive-side and the negative-side, and the detected signals are respectively detected. The difference is subtracted by the two differential amplifiers, and the unbalanced amount in the first differential amplifier is output to the determination means as a digital signal in the A / D converter.

The judging means judges whether or not the digital signal from the A / D converter is within a predetermined range. Then, the increase / decrease control means increases / decreases the initial data of the storage means based on the judgment of the judgment means so that the digital signal from the A / D converter falls within a predetermined range and stores it in the storage means. Then, the D / A converter converts the increase / decrease data stored in the storage means into an analog signal, and based on the analog conversion data in the D / A converter, the balance adjusting means causes the first photodetector to operate. And the balance of the analog signal between the second photodetector and the second photodetector is adjusted and output to the first differential amplifier.

Next, the output signal of the first differential amplifier is detected again into two types of DC voltage on the positive side and the negative side, and output to the judging means via the second differential amplifier and the A / D converter. Then
The above-mentioned processing is repeated until the digital signal from the A / D converter falls within the predetermined range.

Through such repetitive processing, A / D
The digital signal from the converter falls within a predetermined range, and the tracking error is balanced.

After that, the ON control means turns on the switch when the digital signal from the A / D converter is within a predetermined range based on the judgment of the judgment means, so that the tracking drive circuit is turned on and the tracking servo is turned on. Are driven and controlled.

As a result, it is possible to control the tracking servo by always keeping the tracking error voltage in an appropriate balance state, including the variation of the diffraction grating and the variation of the reflected light for each disk.

According to the second aspect of the present invention, the execution control means stores the increase / decrease data in the storage means each time the disk is started to rotate, so that it is possible to change the environment or the type of disk. Also makes it possible to obtain an appropriate value.

Further, since the median value setting means sets the initial data to the median value within the predetermined range, assuming that the variation of the optical pickup is zero, the adjustment completion time can be minimized. .

As a result, it is possible to improve the operability of the tracking control device.

Further, according to the third aspect of the invention, the turning-on median value setting means sets the initial data after turning on the power to a median value within the predetermined range, so that at first, variations in the optical pickup occur. Assuming zero, the adjustment completion time can be minimized.

On the other hand, if the initial data is always set to the median value within the predetermined range, it takes time to absorb the variations of the optical pickup. Since the increase / decrease data stored in the storage means in 1 above is set as the hold data at the time of the previous disk startup, only the time required for the variation tracking correction due to the change in the environment is required. Therefore, the time required to complete the adjustment can be shortened.

As a result, it is possible to improve the operability of the tracking control device.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 5, the optical disk reproducing apparatus of this embodiment comprises a main beam 1 for reading an information signal of a disk (not shown), a first auxiliary beam 2 for detecting a tracking error, and a second auxiliary beam 3. The first auxiliary beam 2 and the second auxiliary beam 3 are incident so that the light beams are symmetrical with respect to the direction along the pit track 4 about the main beam 1 and the direction orthogonal thereto. It is like this.

A tracking control device for controlling the main beam 1 so as not to deviate from the center of the pit track 4 includes a first photodetector 5 and a second photodetector 6 as shown in FIG. The first auxiliary beam 2 and the second auxiliary beam
The reflected light from the auxiliary beam 3 is detected by the first photodetector 5 and the second photodetector 6, respectively.

The above-mentioned first photodetector 5 and second photodetector 6
Are connected to a balance adjusting circuit 7 as balance adjusting means. This balance adjustment circuit 7 uses the respective I / V converters (not shown) to convert the current signal Ie and the current signal If detected by the first photodetector 5 and the second photodetector 6 into a voltage signal Ve and a voltage signal. The voltage signal Ve is converted into Vf, and the voltage signal Ve is balanced by an adjustment voltage Vc from a D / A converter 19 described later. That is, as shown in FIG. 2, the balance adjusting circuit 7 includes two FETs (Field Effect Transistors) 20.
21 and Ve> Vf when the adjustment voltage Vc is a positive voltage, and Ve <V when the adjustment voltage Vc is negative.
The balance is adjusted to be f.

The balance adjusting circuit 7 is connected to a first differential amplifier 8, and the first differential amplifier 8 has a tracking drive circuit 10 having a tracking coil 11 via a switch 9 as shown in FIG. It is connected to the.

The first differential amplifier 8 outputs the difference between the voltage signal Ve and the voltage signal Vf output from the balance adjusting circuit 7. In addition, the tracking drive circuit 10 energizes the tracking coil 11 to move an optical pickup (not shown) in the tracking direction to move the main beam 1, the first auxiliary beam 2, and the second auxiliary beam 3 in the radial direction of the disc. It is something to move.

On the other hand, the output terminal 12 of the first differential amplifier 8 has a positive side detector 13 for detecting the positive side portion and a negative side for detecting the negative side portion from the output signal of the first differential amplifier 8. The positive-side detector 13 and the negative-side detector 14 are respectively connected to the detector 14, and the positive-side detector 13 and the negative-side detector 14 are connected to the second differential amplifier 15,
And a CPU (Central Processing Unit) 17 via an A / D converter 16 for converting an analog signal into a digital signal.
It is connected to the.

The CPU 17 has a function as a judging means for judging whether or not the data input value is within a predetermined range based on the data input from the A / D converter 16, and the judging means. It has a function as an increase / decrease control means for increasing / decreasing initial data of the memory 18 to be described later so as to make the digital signal of the A / D converter 16 fall within a predetermined range based on the judgment of FIG.

Further, the CPU 17 has a function as an ON control means for turning on the switch 9 when the digital signal of the A / D converter 16 falls within a predetermined range based on the judgment of the judgment means.

Further, the CPU 17 has a function as an execution control means for storing the increase / decrease data in the memory 18 every time the disk is started and a median value setting means for setting the above-mentioned initial data to a median value within a predetermined range. On the other hand, a power-on median value setting means for setting the initial data after power-on to a median value within the predetermined range, and the increase / decrease data stored in the memory 18 each time the disk is booted, It has a function as an increase / decrease data holding unit which is set in the held data.

A memory 18 as a storage means capable of storing 8-bit data is connected to the CPU 17 and the memory 18 is designed to initially store initial data.

Further, the CPU 17 is connected to the balance adjusting circuit 7 via a D / A converter 19, and the output signal of the CPU 17 is converted into a digital signal by the D / A converter 19 into an analog signal. Is output to the balance adjusting circuit 7. At this time, the D / A converter 19 outputs the adjustment voltage Vc of 0V as the adjustment signal when the output signal of the CPU 17 is 80H, and the CPU 1
When the output signal of 7 exceeds 80H, the adjustment voltage Vc of the positive voltage is output, and when the output signal of the CPU 17 is less than 80H, the adjustment voltage Vc of the negative voltage is output.

The tracking control of the tracking control device of the optical disk reproducing device having the above configuration will be described with reference to the flowchart of FIG.

First, as shown in FIG. 3, initial data 80H (Hex display value) is written in the memory 18 as balance data (S1). Further, since the tracking servo is not driven at first, the switch 9 of the tracking drive circuit 10 is turned off (S2). Then, after determining whether or not the disc is mounted (S
3) After the focus becomes OK (S4), the spindle motor is driven to rotate the disc (S5).

As a result, as shown in FIGS. 1 and 2, the reflected lights from the first auxiliary beam 2 and the second auxiliary beam 3 are detected by the first photodetector 5 and the second photodetector 6, respectively. The balance adjustment circuit 7 adjusts the balance between the voltage signal Ve and the voltage signal Vf described below.

First, since the adjustment voltage Vc from the D / A converter 19 has the initial data of 0 V, the signals from the first photodetector 5 and the second photodetector 6 are directly the voltage signal Ve. And the voltage signal Vf is output to the first differential amplifier 8.

By the way, at this time, variations in the diffraction grating,
Alternatively, when there is a deviation in the tracking error balance on the disc, the voltage signal Ve is not equal to the voltage signal Vf,
The output of the first differential amplifier 8 is as shown in FIGS. That is, when voltage signal Ve> voltage signal Vf, the output shown in FIG. 4A is obtained, and when voltage signal Ve <voltage signal Vf, the output shown in FIG. 4C is obtained. In addition,
When voltage signal Ve = voltage signal Vf, the output shown in FIG.

The tracking error voltage Ve-Vf of the first differential amplifier 8 is the positive side detector 13 and the negative side detector 1.
4 detects the positive side and the negative side respectively, and the second differential amplifier 15 obtains the DC voltage of the tracking error. For example, assuming that the voltage signal Ve> the voltage signal Vf due to the variation of the diffraction grating or the disk, the output of the second differential amplifier 15 becomes a positive voltage, and the A / D converter 16 outputs A.
The data after the / D conversion (8 bits) is 80H or more.

Now, returning to the flowchart of FIG. 3,
After S5, the CPU 17 determines whether the data input value from the A / D converter 16 is between 70H and 90H (S6). If the data input value is between 70H and 90H, the switch 9 is turned on (S7), and the tracking servo is turned on by the tracking drive circuit 10.
And shifts to the normal reproduction operation (S8).

On the other hand, when the data input value is not within the range of 70H to 90H, it is judged whether the data input value is larger than 80H or not, so that voltage signal Ve> voltage signal V
It is determined whether f or voltage signal Ve <voltage signal Vf (S
9). That is, when the data input value is larger than 80H, the voltage signal Ve> the voltage signal Vf.
The CPU 17 writes a numerical value lower than the reference value 80H in the memory 18 and outputs it to the D / A converter 19 (S1).
0). As a result, the D / A converter 19 outputs the negative voltage adjustment voltage Vc, so that the balance adjustment circuit 7:
The output voltage Ve decreases, which causes the first differential amplifier 8
Therefore, the tracking error voltage Ve-Vf of the above will decrease. Then, by returning to S6 of FIG. 3, the determination as to whether or not the data input value is between 70H and 90H is repeated.

On the other hand, when the data input value is smaller than 80H, the voltage signal Ve is smaller than the voltage signal Vf. Therefore, the CPU 17 raises the data value of the memory 18 and outputs it to the D / A converter 19 (S11). ), In the balance adjustment circuit 7, the output voltage Ve increases, which causes the tracking error voltage Ve-Vf of the first differential amplifier 8.
Will decrease, and the process will return to S6 again. Then, the check operation is repeated until the data input value to the CPU 17 finally falls within the range of 70H to 90H, that is, until the tracking error balance reaches an appropriate value, whereby the tracking servo is always performed in the optimum balance state. To do so.

As described above, when performing tracking control of the disc, the tracking control device of the optical disc reproducing device of the present embodiment first turns the switch 9 to the OFF state to rotate the disc, and then the first auxiliary beam and the second auxiliary beam. The respective signals generated by the first photodetector 5 and the second photodetector 6 that detect the reflected light of each auxiliary beam are input to the balance adjustment circuit 7.

In parallel with this balance adjusting circuit 7,
Predetermined initial data preset in the memory 18 is
It is converted into an analog signal by the D / A converter 19 and input. It should be noted that the initial data is set such that 0 V is applied to the D / A converter 18 at first, so that there is a difference in the magnitude of each signal generated in the first photodetector 5 and the second photodetector 6. If not, the balance adjustment circuit 7 outputs the signals generated by the first photodetector 5 and the second photodetector 6 to the first differential amplifier 8 as they are, so that the signals are balanced.

Here, for example, the output from the first differential amplifier 8 may not be 0V due to variations in the diffraction grating and the disks.

At this time, the output signal of the first differential amplifier 8 is detected by the positive-side detector 13 and the negative-side detector 14 into two types of DC voltage, that is, the positive side and the negative side, and each of the detected direct-current voltages is detected. The signal is subtracted by the second differential amplifier 15, and the unbalanced amount in the first differential amplifier 8 is A / D converter 16
As a digital signal, the CPU 17 as a judgment means
Is output to.

The CPU 17 determines whether the digital signal from the A / D converter 16 is within a predetermined range. Next, the CPU 17 as the increase / decrease control means makes the memory 18 so that the digital signal from the A / D converter 16 falls within a predetermined range based on the judgment of the CPU 17 as the judgment means.
The initial data of is increased or decreased and stored in the memory 18. Next, the D / A converter 19 converts the increase / decrease data stored in the memory 18 into an analog signal, and based on the analog conversion data in the D / A converter 19, the balance adjusting circuit 7 causes The balance of analog signals of the photodetector 5 and the second photodetector 6 is adjusted and output to the first differential amplifier 8.

Next, the output signal of the first differential amplifier 8 is detected again into two types of DC voltage on the positive side and the negative side, and the CPU 1 is processed via the second differential amplifier 15 and the A / D converter 16.
To the A / D converter 16 by the same processing as described above.
Is repeated until the digital signal from is within a predetermined range.

By repeating such processing, A / D
The digital signal from the converter 16 falls within a predetermined range, and the tracking error balance is achieved.

After that, the CPU 17 as ON control means
However, based on the judgment of the CPU 17 as the judgment means, A
Since the switch 9 is turned on when the digital signal from the / D converter 16 is within the predetermined range, the tracking drive circuit 10 is turned on and the tracking servo is drive-controlled.

As a result, it is possible to control the tracking servo by keeping the tracking error voltage in a proper balance state, including the dispersion of the diffraction grating and the dispersion of the reflected light of each disk.

Further, the tracking control device of the optical disc reproducing apparatus of the present embodiment has the CPU 1 as the execution control means.
7 causes the memory 18 to store the increased / decreased data every time the disk is started to rotate, so that an appropriate value can be obtained even if the environment changes or the type of the disk changes.

Further, the CPU 1 as the median value setting means
7 sets the initial data within the predetermined range (70H to 90H)
Is set to the median value (80H), it is possible to minimize the adjustment completion time, assuming that the variation of the optical pickup is zero. As a result, it is possible to improve the operability of the tracking control device.

Further, in the tracking control device of the optical disc reproducing apparatus of the present embodiment, the CPU 17 as the median value setting means at power-on sets the initial data after power-on to the median value within the predetermined range. Assuming that the variation of the optical pickup is zero, the adjustment completion time can be minimized.

On the other hand, if the initial data is always set to the median value within the predetermined range, it takes time to absorb the variations of the optical pickup. However, after the second time, the CPU 17 as the increase / decrease data holding means makes the disk Since the increase / decrease data stored in the memory 18 at each start-up is set as the holding data at the previous start-up of the disk, only the time required for the variation tracking correction due to the change in the environment is required. Therefore, the time required to complete the adjustment can be shortened. As a result, it is possible to improve the operability of the tracking control device.

[0061]

As described above, the tracking control apparatus for the optical disk reproducing apparatus according to the first aspect of the present invention includes the positive side detector for detecting the output signal of the first differential amplifier to the positive side, and the first differential amplifier. Negative side detector for detecting the output signal of the negative side to the negative side, a second differential amplifier for subtracting the two signals of the positive side detector and the negative side detector, and a digital signal for the analog signal of the second differential amplifier. A / D converter for converting into a digital signal, determination means for determining whether or not the digital signal from the A / D converter is within a predetermined range, storage means for storing predetermined initial data, and determination by the determination means. Based on the above, the increase / decrease control means for increasing / decreasing the initial data of the storage means so that the digital signal from the A / D converter falls within a predetermined range and storing the same in the storage means, and the increase / decrease data stored in the storage means are analog signals. D / A converter for converting to The balance adjusting means for adjusting the balance of the analog signals of the first photodetector and the second photodetector based on the analog conversion data in the D / A converter and outputting the balance to the first differential amplifier, and tracking. A switch for turning on / off the servo drive and an ON control means for turning on the switch when the digital signal from the A / D converter is within a predetermined range based on the judgment of the judgment means are provided. It is a composition.

As a result, when the tracking control of the disk is performed and the output of the first differential amplifier is not 0 V due to variations in the diffraction grating and the disks, the switch is turned off first. Then rotate the disc. Next, the output signal of the first differential amplifier is detected into two types of DC voltage on the positive side and the negative side, which is output to the determination means via the second differential amplifier and the A / D converter, and the D / A Feedback is made to the balance adjusting means via the converter. Then, the processing is repeated until the digital signal from the A / D converter falls within the predetermined range. By such an iterative process, the digital signal from the A / D converter falls within a predetermined range, and the tracking error balance is achieved. After that, the ON control means turns on the switch when the digital signal from the A / D converter is within the predetermined range based on the judgment of the judgment means, so that the tracking drive circuit is turned on and the tracking servo is driven and controlled. To be done.

As a result, it is possible to control the tracking servo by keeping the tracking error voltage always in an appropriate balance state, including the dispersion of the diffraction grating and the dispersion of the reflected light of each disk.

As described above, the tracking control device for the optical disk reproducing apparatus according to the second aspect of the present invention, in the tracking control device for the optical disk reproducing apparatus according to the first aspect, increases / decreases data to / from the storage means each time the disk is started to rotate. And a median value setting device for setting the initial data to a median value within the predetermined range.

As a result, the execution control means causes the storage means to store the increased / decreased data every time the disk is started, so that an appropriate value can be obtained even if the environment changes or the type of the disk changes. Becomes

Further, since the median value setting means sets the initial data to the median value within the predetermined range, assuming that the variation of the optical pickup is zero, the adjustment completion time can be minimized. .

As a result, the operability of the tracking control device can be improved.

As described above, the tracking control device for the optical disc reproducing apparatus according to the third aspect of the present invention is the tracking control device for the optical disc reproducing apparatus according to the first aspect, wherein the initial data after power-on is within the predetermined range. There is provided a median value setting means at the time of closing for setting the median value and an increase / decrease data holding means for setting the increase / decrease data stored in the storage means each time the disk is started as the hold data at the previous disk startup. It is a composition.

As a result, the turning-on median value setting means sets the initial data after turning on the power to a median value within the predetermined range. Therefore, assuming that the variation of the optical pickup is zero at first, adjustment is made. It is possible to minimize the completion time.

On the other hand, if the initial data is always set to the median value within the predetermined range, it takes time to absorb the variation of the optical pickup. Since the increase / decrease data stored in the storage means in 1 above is set as the hold data at the time of the previous disk startup, only the time required for the variation tracking correction due to the change in the environment is required. Therefore, the time required to complete the adjustment can be shortened.

As a result, the operability of the tracking control device can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a tracking control device of an optical disk reproducing device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a balance adjustment circuit of the tracking control device.

FIG. 3 is a flowchart showing a processing procedure of balance adjustment in the tracking control device.

FIG. 4 is a waveform diagram showing an output signal of the first differential amplifier in the tracking control device, (a) being Ve> V.
f and (b) show Ve = Vf, and (c) shows Ve <Vf.

FIG. 5 is a plan view showing a positional relationship between a main beam and an auxiliary beam in the optical disc reproducing apparatus.

FIG. 6 shows a conventional example and is a block diagram showing a configuration of a tracking control device of an optical disc reproducing device.

[Explanation of symbols]

1 Main Beam 2/3 Auxiliary Beam 4 Pit Track 5 First Photo Detector 6 Second Photo Detector 7 Balance Adjusting Circuit (Balance Adjusting Means) 8 First Differential Amplifier 9 Switch 10 Tracking Drive Circuit 13 Positive Side Detector 14 Negative side detector 15 Second differential amplifier 16 A / D converter 17 CPU (judging means, increase / decrease control means, ON control means, execution control means, median value setting means, input median value setting means, increase / decrease data holding means ) 18 memory (storage means) 19 D / A converter

Claims (3)

[Claims] 1. A main beam for reading an information signal recorded on a disc, a first auxiliary beam and a second auxiliary beam used for tracking error detection, and a first auxiliary beam and a second auxiliary beam, respectively. A first photodetector and a second photodetector that detect reflected light, a first differential amplifier that subtracts each signal generated by the first photodetector and the second photodetector, and a first differential A tracking control device for an optical disk reproducing device, comprising a tracking drive circuit for driving a tracking servo based on the output of an amplifier, comprising: a positive side detector for detecting the output signal of the first differential amplifier to a positive side; A negative-side detector that detects the output signal of the differential amplifier to the negative side, a second differential amplifier that subtracts the two signals of these positive-side detector and negative-side detector, and an analog signal of the second differential amplifier The de An A / D converter for converting into a digital signal,
A judging means for judging whether or not the digital signal from the A / D converter is within a predetermined range, a storing means for storing predetermined initial data, and a digital signal from the A / D converter based on the judgment of the judging means. An increase / decrease control means for increasing / decreasing the initial data of the storage means so that the signal falls within a predetermined range and storing the same in the storage means; and a D / A converter for converting the increase / decrease data stored in the storage means into an analog signal, The first photodetector and the second photodetector based on the analog conversion data from the D / A converter.
A balance adjusting means for adjusting the balance of the analog signal with the photodetector and outputting it to the first differential amplifier, a switch for turning ON / OFF the drive of the tracking servo, and A / D conversion based on the judgment of the judging means. An ON control means for turning on the switch when a digital signal from the device is within a predetermined range, and a tracking control device for an optical disk reproducing device. 2. An execution control means for executing storage of increase / decrease data in the storage means each time the disk is started, and a median value setting means for setting the initial data to a median value within the predetermined range. The tracking control device of the optical disk reproducing device according to claim 1, wherein 3. A start-up median value setting means for setting the above-mentioned initial data after power-on to a median value within the predetermined range, and the increase / decrease data stored in the storage means at each time of start-up of the disk for the previous disk start-up. 2. The tracking control device for an optical disk reproducing device according to claim 1, further comprising an increase / decrease data holding means for setting the holding data at the time.