JP2929688B2 - Optical disc apparatus and tracking offset adjustment method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc device that adjusts a tracking offset every time an information signal is recorded and reproduced, and a tracking offset adjusting method used in the optical disc device. .

B. Summary of the Invention The present invention relates to recording of an information signal on an optical disc and / or
Alternatively, at the start of reproduction, a tracking error signal representing a displacement corresponding to a displacement of the objective lens with respect to an arbitrary track of the optical disc in one direction and a displacement in the other direction opposite to the one direction is generated. The tracking offset amount is detected based on the tracking error signal, and the tracking offset is reduced based on the detected tracking offset amount. An optical disc device capable of suppressing a tracking offset and enabling good recording and / or reproduction of an information signal and a tracking offset adjusting method used in the optical disc device.

C. Prior Art Conventionally, an optical disc device that records and / or reproduces an information signal using an optical disc that is an optical recording medium has been used.

This type of optical disk is mounted on an optical disk rotation operation mechanism and rotated, and a signal recording area of the rotated optical disk is operated by a light beam emitted from an optical pickup device to record or record an information signal. Playback is performed.

In this optical disk device, it is necessary to converge and irradiate a light beam on a recording track formed concentrically or spirally on a signal recording surface of the optical disk. That is, the optical disc device writes an information signal on the recording track by irradiating the recording track with a light beam, or detects the amount of light, the polarization direction, and the like of the return light of the light beam irradiated on the recording track. Thus, the information signal written on the recording track is read.

When the optical disk is rotated by the disk rotation operation mechanism, if the center of curvature of the recording track and the drive shaft of the spindle motor which is the rotation center of the disk rotation operation mechanism are eccentric, the recording track is synchronized with the rotation of the optical disk. The optical disk moves in the radial direction. Therefore, in the optical pickup device, a deviation between the beam spot where the light beam is focused and the recording track, that is, a tracking error is detected, and the entire optical pickup device or the light beam is focused according to the tracking error. It is necessary to drive and displace the objective lens in the radial direction of the optical disc.

As a means for detecting a tracking error, a so-called three-beam optical pickup device has been proposed. This three-beam optical pickup device divides a light beam emitted from a light source such as a semiconductor laser into three light beams using a light beam splitting means such as a diffraction grating.
As shown in FIG. 7, three beam spots m, s ₁ and s ₂ are formed on the optical disk on which the recording tracks t are formed.

In this optical pickup device, a main spot m located at the center among the three beam spots m, s ₁ , and s ₂ is a beam spot for writing and / or reading an information signal to and from a recording track t. is there. Then, the first and second sub-spots s ₁ and s ₂ formed in pairs on both sides of the main spot m are formed between the main spot m and the recording track t in the direction of arrow r in FIG. This is a beam spot for detecting a deviation in the radial direction of the optical disc, that is, a tracking error. Each of these sub spots s _1, s _2, when the main spot m is positioned on the recording track t, for each recording track t, 7 in the arrow r ₁ and radial directions of the arrow r ₂ direction of the optical disk And are formed at positions shifted by an equal distance in opposite directions.

And the first sub spot s ₁ is the main spot m
7 an arrow in the drawing but the direction of displacement with respect to the first recording track t subspots s ₁ with respect to the recording track t
Moving to r ₁ direction, and moves with the main spot m, the amount of deviation of the recording track t is made large. At this time, the second sub-spot s ₂ moves together with the seventh in the arrow r ₁ direction is the direction of the deviation of the first recording track t subspots s ₁ main spot m,
The amount of deviation from the recording track t is reduced.

The second sub-spot s _2, to the main scan raised dot m recording track t, when moving in the direction of the deviation of 7 in the arrow r ₂ the direction of the second recording tracks t subspots s ₂ In addition, the amount of deviation from the recording track t is increased. At this time, the first sub-spot s ₁ is in the direction of the deviation of the second sub-spots s ₂ of the recording tracks t to move the seventh in the arrow r ₂ direction, the amount of deviation of the recording track t Is made smaller.

Since the reflectance of light is different between the recording track t and the portion deviating from the recording track t, in this optical pickup device, the difference between the reflected light amounts of the sub-spots s ₁ and s ₂ is the recording of the main spot m. This corresponds to the direction and amount of deviation from the track t. Therefore, each sub-spot
The reflected light amounts of s ₁ and s ₂ are detected independently, and a tracking error is detected from the difference between these detection signals. When the main spot m is located on the recording track t, the difference obtained from the detection signals of the sub spots s ₁ and s ₂ becomes zero.

An optical disk device provided with such an optical pickup device is, as shown in FIG.
The first optical detection signal E obtained by detecting the return light of the first sub-spot s ₁ from the optical pickup device 103 disposed opposite to the optical disk 102 rotated by 1
If a second optical detection signal F obtained by detecting the second sub-spots s ₂ of the return light is detected independently.
These light detection signals E and F are sent to the RF amplifier 104, respectively.

In the RF amplifier 104, the first light detection signal E is amplified by a first comparator 109 serving as an amplifier. Also,
The second light detection signal F is supplied to a second comparator 110 serving as an amplifier.
Amplified by These first and second comparators 109, 11
Outputs of 0 are subtracted from each other by a subtractor 111 and output as a tracking error signal Te.

The tracking error signal Te is sent to the drive control circuit 106 via the equalizer circuit 105. The drive control circuit 106
Based on the sent tracking error signal Te, the driving device 107 is controlled so as to move the optical pickup device 103 or the objective lens in the radial direction of the optical disc 102. At this time, the drive control circuit 106 sets the first light detection signal E and the second
Drive device such that the difference in the detection power of the light detection signal F becomes zero
Control 107. That is, the optical pickup device 103 or the objective lens is driven and displaced in the radial direction of the optical disc 102 in accordance with the tracking error signal Te, and the position is controlled so that the main spot m is positioned on the recording track t.

Incidentally, the tracking error signal may cause a so-called tracking offset due to a change in characteristics of an optical device or a photodetector constituting the optical pickup device 103, or a characteristic of an element constituting a circuit such as the RF amplifier 104. When this tracking offset occurs, the tracking error signal Te becomes zero when the difference between the detection powers of the first light detection signal E and the second light detection signal F becomes zero when the main spot m is located on the recording track t. Will not be. Then, the position of the optical pickup device 103 is controlled so as to form the main spot m at a position deviated from the recording track t. Main spot m is recording track t
If it is formed at a further deviated position, it becomes impossible to perform good writing and / or reading of the information signal on the recording track t.

Therefore, in the optical disk device, a variable resistor 108 is connected to the RF amplifier 104 so that a tracking offset does not occur. This variable resistor 108 is connected to the second comparator 1
The second comparator 110 is configured to vary the amplification gain. In this optical disk device, the variable resistor 108 is adjusted in the manufacturing process, and the tracking resistor is adjusted so as not to generate a tracking offset.

In this tracking offset adjustment, the center of the amplitude of the tracking error signal Te output from the RF amplifier 104 becomes 0 while the operation of moving the optical pickup device 103 or the objective lens by the drive control circuit 106 is stopped. Is adjusted as follows.

D. Problems to be Solved by the Invention By the way, as described above, in an optical disk device that is adjusted so that the tracking offset becomes 0 at the time of manufacturing using the variable resistor 108, the tracking offset is equal to the optical pickup device 103. The adjustment is made in accordance with the initial specification of the constituent optical device, the light detecting element, or the constituent element of the circuit such as the RF amplifier 104. Therefore, in this optical disk device, if the characteristics of the optical device, the photodetector, and the elements constituting each circuit change over time, the tracking offset may increase.

That is, in this optical disc device, there is a possibility that the information signal cannot be recorded and / or reproduced properly after being used for a long time.

Further, in the optical disk device, an adjustment process for setting the tracking offset to 0 cannot be omitted in the manufacturing process, and the manufacturing process cannot be simplified.

Therefore, an object of the present invention is proposed in view of the above-mentioned circumstances, and it is possible to suppress occurrence of a tracking offset, accurately record and / or reproduce an information signal, and facilitate manufacturing. An object of the present invention is to provide a simple optical disk and a tracking offset adjusting method used in the optical disk device.

E. Means for Solving the Problems In order to solve the above problems and achieve the above object, an optical disk device according to the present invention irradiates an optical disk with a light beam from an objective lens and detects reflected light from the optical disk. Based on the detection unit and the reflected light detected by the detection unit, the objective lens corresponds to a shift in one direction with respect to an arbitrary track of the optical disc and a shift in another direction opposite to the one direction. A tracking error generating means for generating a tracking error signal indicating the amount of displacement, and a tracking error corresponding to one of a displacement in one direction and a displacement in the other direction outputted from the tracking error generating means. Tracking offset adjusting means for adjusting the signal offset amount; and a signal output from the tracking error generating means. And equalizer means for performing Tsu King equalizer process to the error signal, a driving means for the objective lens is driven in the radial direction of the optical disc based on the tracking error signal equalizer process has been performed from said equalizer means,
Low-frequency component extraction means for extracting a low-frequency component of the tracking error signal output from the tracking error generation means, and polarity determination for determining the polarity of the low-frequency component of the tracking error signal extracted by the low-frequency component extraction means Means, a shift voltage generating means for generating a first shift voltage for shifting in an inner circumferential direction of the optical disk and a second shift voltage for shifting in an outer circumferential direction of the optical disk to the driving means, and a tracking servo loop opened. In this state, the first shift voltage and the second shift voltage generated by the shift voltage generating means are sequentially applied to the driving means, and the first and second shift voltages are applied to the tracking offset adjusting means in accordance with the polarity obtained from the polarity determining means. It is provided with control means for controlling the offset amount.

F. Function The optical disc apparatus according to the present invention includes a first shift voltage for shifting the objective lens in the inner circumferential direction of the optical disc to a driving unit that drives the objective lens in the radial direction of the optical disc while the tracking servo loop is opened. A second shift voltage for sequentially shifting the objective lens in the outer circumferential direction of the optical disk is sequentially applied, and the offset amount in the tracking offset adjusting means according to the polarity obtained from the polarity determining means for determining the polarity of the low frequency component of the tracking error signal Is controlled.

G. Embodiment Hereinafter, an optical disc device and a tracking offset adjustment method according to the present invention will be described with reference to the drawings.

An optical disk device according to the present invention records or reproduces an information signal using an optical disk which is an optical recording medium. As shown in FIG. 1, the optical disk device has a disk rotation operation mechanism 101 that holds the center of the optical disk 102 and rotates the optical disk.

Also, the optical disk device has a disk rotation operation mechanism 101.
An optical pickup device 103 is provided so as to face the optical disc 102 mounted on the optical disc 102. The optical pickup device 103 includes a light source such as a semiconductor laser, an objective lens and other optical devices that converge and irradiate a light beam emitted from the light source onto a signal recording surface of the optical disk 102, and further returns light reflected from the optical disk 102. A light detector for detecting light is provided.

The optical pickup device 103 used here is a so-called three-beam type optical pickup device, and as shown in FIG. 7, the signal recording on the optical disk 102 on which the recording track t is formed concentrically or spirally. a light beam is irradiated onto the surface to form a three beam spots of the main spot m, the first sub-spot s ₁ and second sub-spots s _2. This optical pickup device 103
By forming a main spot m on the recording track t, an information signal is written on the recording track t, or by detecting return light of the main spot m formed on the recording track t from the optical disk 102, The information signal written at t is read. Then, the difference between the light amounts of the sub-spots s ₁ and s ₂ of the return light from the optical disk 102 corresponds to a shift between the recording track t and the main spot m, that is, a tracking error.

The optical pickup device 103 individually detects the light amount of the return light from the optical disk 102 for each of the first and second sub-spots s ₁ and s ₂ by a photodetector. And the first
The detection signal detected based on the sub-spot s ₁ of the first
The output as an optical detection signal E, and outputs a detection signal detected based on the second sub-spots s ₂ as the second optical detection signal F. In the optical pickup device 103, a detection signal detected based on the main spot m is output as a read signal G and supplied to a control device 17 described later.

In this optical disk device, the first and second light detection outputs E and F are sent to an RF amplifier (high frequency amplifier) 1.

The RF amplifier 1 includes first and second comparators 2,
3 is provided. The input terminal of the first comparator 2 receives a first light detection signal E and is grounded via first and second resistors 4 and 5 connected in series. Also,
The output terminal of the first comparator 2 is grounded via a third resistor 6 and a second resistor 5 connected in series.
The amplification factor of the first light detection output E supplied to the first comparator 2 is determined by the resistance values of the first to third resistors 4, 5, and 6.

The second photodetection signal F is input to the input terminal of the second comparator 3 and the fourth terminal
, And a grounding via a variable resistance section 8 constituting a tracking offset adjusting means. The output terminal of the second comparator 3 is grounded via a fifth resistor 9 and a variable resistor 8 connected in series. The amplification factor of the second light detection output F supplied to the second comparator 3 is determined by the resistance values of the fourth and fifth resistors 7, 9 and the variable resistor section 8.

The variable resistor section 8 includes sixth to ninth four resistors 10, 11, 12, and 13 connected in parallel with each other. 6th resistor 10
Has one end connected to the fourth resistor 7 and the fifth resistor 9 and the other end grounded. The seventh resistor 11 has one end connected to the fourth resistor 7 and the fifth resistor 9 and the other end grounded via the first switching transistor 14. The eighth resistor 12 has one end connected to the fourth resistor 7 and the fifth resistor 7.
And the other end is grounded via the second switching transistor 15. The ninth resistor 13 is
One end is connected to the fourth resistor 7 and the fifth resistor 9, and the other end is grounded via the third switching transistor 16.

First to third switching transistors 14, 15, 16
The switching of is controlled by the control device 17 which constitutes a tracking offset adjusting means having a CPU. That is, the control device 17 controls the switching transistors 14, 1
By selectively turning on the conductive layers 5 and 16, the combined resistance value of the variable resistance section 8 can be changed, and the amplification factor of the second light detection output F in the second comparator 3 can be changed.
The combined resistance value of the variable resistance section 8 is changed in eight steps.

Then, the output signals of the first and second comparators 2 and 3 are sent to a subtractor 18 and subjected to a subtraction process. The output signal of the subtractor 18 is output from the RF amplifier 1 as a tracking error signal Te. This tracking error signal Te
Is a difference signal between the output signals of the first and second comparators 2 and 3. Therefore, when the combined resistance value of the variable resistance unit 8 is variably operated and the amplification factor in the second comparator 3 changes, the signal The center value of the level fluctuation, that is, the tracking offset is changed.

Here, as shown in FIG. 5, the tracking offset corresponds to the combined resistance value of the variable resistance section 8 in eight stages, as shown in FIG.
It can be changed in eight steps. Assuming that the value of the tracking offset that can be changed in this way is TO ₃ , this TO ₃ is 0H
To 7H. Here, 0H to 3H correspond to +3 to +0 in the offset level, and 4H to 7H.
Corresponds to −0 to −3 in the offset level. Incidentally, in this FIG. 5, the first switching transistor 14 is indicated by TO2 _P, H conductive state, L indicates respectively the insulated state. Similarly, the second
The third switching transistor 16 is TO0 _P , H is conductive, and L is an insulating state. The switching transistor 15 of TO1 _P , H indicates a conductive state, and L indicates an insulating state.

The tracking error signal Te is sent to an input terminal of an equalizer circuit 19 constituting a movement control means together with the control device 17. Further, the tracking error signal Te forms a part of the equalizer circuit 19 through the low-pass filter 20,
The signal is sent to the comparator circuit section 21 which constitutes the detecting means together with the control device 17.

The low-pass filter 20 has a tenth resistor 22 to which the tracking error signal Te is input from one end and the other end is connected to the comparator circuit unit 21, and a capacitor in which the other end of the tenth resistor is connected in series. 23 and the fourth switching transistor 24 are grounded. The switching of the fourth switching transistor 24 is controlled by the control device 17. That is, the control device 17 can perform the switching control of the fourth switching transistor 24 to be in the conductive state, so that the low-pass filter 20 can be in the operating state.

Tracking error signal sent to equalizer circuit 19
Te is subjected to predetermined signal processing by the equalizer circuit 19 and sent to the drive control circuit 25. This drive control circuit 25
Drives and controls the driving device 107 provided in the optical pickup device 103 in accordance with the sent tracking error signal Te. The drive device 107 is controlled by the drive control circuit 25, and controls the position of the optical pickup device 103 by moving the entire optical pickup device 103 or the objective lens in the radial direction of the optical disc 102.

Therefore, the objective lens has a tracking error signal
The optical disk follows the recording track t according to Te
It is moved in the radial direction of 102. That is, the optical disk device has a so-called tracking servo function.

This optical disk device also has a so-called focus servo function. In other words, in this optical disc device, the focal point of the light beam emitted from the objective lens based on the output signal from the optical pickup device 103 and the signal recording surface of the optical disc are displaced in a direction perpendicular to the signal recording surface, That is, a focus error is detected, and a focus error signal indicating the amount of the focus error is generated. The objective lens is moved in the direction of the optical axis of the objective lens based on the focus error signal, and the position of the objective lens is controlled so that the light beam is focused on the signal recording surface of the optical disk.

The control device 17 supplies a control signal such as a track jump signal to the equalizer circuit 19, and
In addition, it controls the movement of the objective lens in the radial direction of the optical disk 102 and controls the disk rotation operation mechanism 101. At this time, the comparator circuit section 21 generates a TZC signal, which is a signal indicating a result of comparing the tracking error signal Te with the reference level signal, and sends the signal to the control device 17. The control device 17 controls the optical disc 1 based on the TZC signal.
Optical pickup device 103 operated to move in the radial direction of 02
Control the acceleration and deceleration of the vehicle.

Further, the control unit 17 is connected to the operation unit 26 and the display unit 27, and various operation modes are selected.
A display such as an operation state is performed.

In this optical disk apparatus, an optical disk 102 is mounted on a disk rotation operation mechanism 101, and a control device 17 is provided before recording and / or reproducing information signals on the optical disk 102.
Adjustment of the tracking offset value TO ₃ is carried out by.

That is, the optical disk 102 is
The controller 17 sets various initial values in step st1, as shown in the flowchart of FIG. 2, and proceeds to step st2. By setting the initial value in this step st1, the tracking offset value TO ₃
Is set to 4H after each first switching transistor 14 is turned on. Further, the fourth switching transistor 24 for operating the low-pass filter 20 is in a state in which the low-pass filter 20 is not operated, that is, in a directly connected state. Furthermore, the focus gain, which is the amplification factor for the focus error signal, the tracking gain, which is the amplification factor for the tracking error signal Te, are initialized, the focus servo function is activated, and the tracking servo function is not activated. Is made.

Then, in step st2, the control device 17 adjusts the focus offset, and proceeds to step st3.
The adjustment of the focus offset in step st2 is performed based on the focus error signal using the comparator circuit unit 21 by controlling the movement of the objective lens in the optical axis direction.

In step st3, the control device 17 controls the disk rotation operation mechanism 101 to rotate the optical disk 102, and moves the optical pickup device 103 to the innermost peripheral side of the optical disk 102. Further, the control device 17 turns on the light source of the optical pickup device 103 and activates the focus servo function so that the respective beam spots m, s ₁ and s ₂ are formed on the signal recording surface of the optical disc 102.
Then, the control device 17 proceeds to step st4.

In step st4, the control device 17 adjusts the tracking offset. That is, the control device 17 proceeds to a tracking offset adjustment subroutine shown in FIG. In step st8, the control device 17 turns on the fourth switching transistor 24 to turn on the low-pass filter 20, and then proceeds to step st9.

In step st9, the control device 17 clears a counter for counting the number of times the tracking offset has been detected, and proceeds to step st10. This counter is
It is built into the control device 17.

In step st10, the control device 17 sets TO3 to 4H as the initial value of the tracking offset value, and proceeds to step st11.

From step st11 to step st14, the control device 17
Controls the movement of the objective lens in the radial direction of the optical disc 102, and detects the center value of the level fluctuation of the tracking error signal Te at this time.

That is, in step st11, the control device 17 moves the objective lens to the inner peripheral side of the optical disc 102 for 0.4 ms. At this time, a tracking jump signal is output from the control device 17 and sent to the equalizer circuit 19, as shown by (A) in FIG. At this time, as shown by (B) in FIG. 6, the tracking error signal Te indicates that the main beam m
, The signal fluctuates with the maximum amplitude across 0V. Then, the control device 17 proceeds to step st12.

Next, in step st12, the control device 17 moves the objective lens to the outer peripheral side of the optical disc 102 for 0.8 ms, and proceeds to step st13.

The control device 17 detects a TZC signal generated by the comparator circuit unit 21 in step st13. Here, the time constant of the low-pass filter 20 is lower than the frequency of the fluctuation of the tracking error signal Te when the objective lens is controlled to move in the radial direction of the optical disc 102, and the period of the tracking jump, that is, 0.4 to 0.8. Is also set short. Therefore, the tracking error signal Te is
After passing through the low-pass filter 20, the signal corresponds to the center value of the amplitude, and the TZC signal is a signal indicating the polarity of the center value. Then, the control device 17 proceeds to step st14.

In step st14, the control device 17 moves the objective lens to the inner peripheral side of the optical disc 102 for 0.4 ms, returns the objective lens to the initial position, and proceeds to step st15.

In step st15, the control device 17 sets the center value of the amplitude of the tracking error signal Te to 0 V based on the TZC signal.
, Ie, whether the TZC signal is “H” or −, ie, whether the TZC signal is “L”. And TZC
If the signal is “H”, the process proceeds to step st16, and if the signal is “L”, the process proceeds to step st17.

In step st16, the control device 17 decreases the tracking offset value TO3 by 1, and proceeds to step st18. That is, TO ₃ up to this point, if assumed to be 4H, the TO ₃ and 3H. However, at this time, since the tracking offset value TO ₃ cannot be made smaller than 0, this value is not reduced when TO ₃ is 0.

In step st17, the control device 17 increases the tracking offset value TO3 by 1, and
Proceed to t18. That, TO3 up to this point is if a was 4H, the TO ₃ and 5H. At this time, since the tracking offset value TO ₃ cannot be made larger than 7, when TO ₃ is 7, this value is not increased.

In step ST18, the control unit 17, the tracking offset is such that the tracking offset value TO ₃ set in step st16 or step ST17, the first to third switching transistors 14, 15 and 16
, Ie, TO2 _P , TO1 _P , TO0 _P shown in FIG.
Is selectively controlled to “H” or “L”. And the control device 17
Proceeds to step st19 as shown in FIG.

In step st19, the control device 17 increases the value of the counter by 1 and proceeds to step st20.

In step st20, the control device 17 determines whether or not the value of the counter is 3, and if it is 3, proceeds to step st21. If not, returns to step st11 to perform the movement control for the objective lens again.

In step st21, the controller 17, the value TO ₃ of the tracking offset is either a 0H or 7H, or to determine neither 0H and 7H. If the tracking offset value TO ₃ is 0H or 7H, step st2
Proceed to 2 and if neither 0H nor 7H, step st23
Proceed to.

In step st22, the control device 17 indicates that an error has occurred in the adjustment of the tracking offset. Here, if the tracking offset value TO ₃ is 0H, in the adjustment of the tracking offset performed by repeating the steps st11 to st18 three times, the step st16 is executed three times, and it is not yet completed. This is because the adjustment of the tracking offset may not be completed. If the tracking offset value TO ₃ is 7H, the step st17 has been executed three times in the tracking offset adjustment, and the tracking offset adjustment is still completed as in the case where the TO ₃ is 0H. This is because they may not have done so. An instruction that an error has occurred in the adjustment of the tracking offset by the control device 17 is sent to, for example, the display unit 27 or the like, and the display unit 27 performs a predetermined display. Then, the control device 17 proceeds to step st23.

In step st23, the control device 17 sets the fourth switching transistor 24 to the cut-off state and the low-pass filter 20 to the non-operating state, and then proceeds to step st5 shown in FIG.
Return to

In step st5, the control device 17 activates the tracking servo function, and proceeds to step st6.

In step st6, the control device 17 adjusts the focus gain, and proceeds to step st7. The adjustment of the focus gain is performed based on the amplitude of the focus error signal.

In step st7, the control device 17 adjusts the trekking gain, and ends the program. This tracking gain adjustment is performed based on the amplitude of the tracking error signal.

In this optical disk device, when the optical disk 102 is mounted on the disk rotation operation mechanism 101, the tracking offset value is set by the controller 17 as described above.
Adjustment of TO ₃ is performed. Therefore, in this optical disk device, the optimal tracking offset is set for each optical disk 102 without being affected by the aging of the characteristics and the like of various optical devices constituting the optical pickup device 103 and the elements constituting each electronic circuit. Good recording and / or reproduction of an information signal can be performed.

H. Effects of the Invention As described above, the optical disc apparatus and the tracking offset adjustment method according to the present invention provide a method of recording and / or reproducing information signals on an optical disc in one direction with respect to an arbitrary track of the optical disc when the objective lens is started. Generating a tracking error signal representing a displacement and a displacement corresponding to the displacement in the other direction opposite to the one direction; detecting a tracking offset amount based on the tracking error signal; Since the offset amount is controlled so as to reduce the tracking offset based on the amount, the tracking offset can be adjusted for each optical disk, and the optical pickup device and various circuits constituting the optical disk device can be adjusted. Even if the characteristics change over time, In response to a change is adjusted tracking offset can always be recorded and / or reproduced satisfactory information signal.

Further, in the manufacturing process, it is possible to eliminate the necessity of adjusting the tracking offset, thereby simplifying the manufacturing process of the optical disc device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of an optical disk device according to the present invention. FIG. 2 is a flow chart for explaining the operation of the control device constituting the tracking offset adjusting device of the optical disk device, and FIGS. 3 and 4 are flow charts for explaining the operation of the tracking offset adjustment of the control device. FIG. 5 is a correspondence table for explaining options of resistance values in the variable resistance section constituting the tracking offset adjusting device. FIG. 6 is a time chart showing waveforms of a track jump signal supplied to a drive control circuit when the objective lens is moved in the radial direction of the optical disk and a tracking error signal at this time in the optical disk apparatus according to the present invention. . FIG. 7 is an enlarged plan view schematically showing the arrangement of beam spots formed on an optical disk by a three-beam optical pickup device. FIG. 8 is a block diagram showing a configuration of a conventional optical disk device. DESCRIPTION OF SYMBOLS 1 ... RF amplifier 2 ... 1st comparator 3 ... 2nd comparator 8 ... Variable resistance part 17 ... Control device 18 ... Subtractor 19 ... Equalizer circuit 21 ... Comparator circuit part 25 ... … Drive control circuit 102… optical disk 103… optical pickup device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 7/09-7/095

Claims (4)

(57) [Claims] A detecting means for irradiating the optical disk with a light beam from an objective lens and detecting reflected light from the optical disk; and detecting an reflected light from the optical disk based on the reflected light detected by the detecting means. Tracking error generating means for generating a tracking error signal representing a displacement in one direction with respect to the track and a displacement in another direction opposite to the one direction; and a tracking error signal output from the tracking error generating means. Tracking offset adjusting means for adjusting the offset amount of the tracking error signal corresponding to one of the displacement in one direction and the displacement in the other direction; and a tracking error signal output from the tracking error generating means. Equalizer means for performing equalizer processing on the Driving means for driving the objective lens in the radial direction of the optical disk based on the tracking error signal on which the equalizer processing has been performed, and a low-frequency component for extracting a low-frequency component of the tracking error signal output from the tracking error generating means. Band component extracting means, polarity determining means for determining the polarity of the low frequency component of the tracking error signal extracted by the low frequency component extracting means, and a first shift for shifting to the driving means in the inner circumferential direction of the optical disk. A shift voltage generating means for generating a voltage and a second shift voltage for shifting the voltage in the outer circumferential direction of the optical disk; and a first shift voltage generated by the shift voltage generating means and a second shift voltage when the tracking servo loop is opened. Are sequentially applied to the driving means, and the trap voltage is applied in accordance with the polarity obtained from the polarity determining means. An optical disc device comprising a control unit for controlling an offset amount by a king offset adjusting unit. 2. The time constant of the low-frequency component extracting means is set shorter than the application time of the first shift voltage and the second shift voltage generated by the shift voltage generating means. The optical disk device according to claim 1, wherein 3. The optical disk device according to claim 1, wherein after the tracking offset adjustment, the low-frequency component extracting means is controlled to be inoperative. 4. A detecting means for irradiating an optical disk with a light beam from an objective lens and detecting reflected light from the optical disk, and based on the reflected light detected by the detecting means, an optional part of the optical disk of the objective lens. Tracking error generating means for generating a tracking error signal representing a displacement in one direction with respect to the track and a displacement in another direction opposite to the one direction; and a tracking error signal output from the tracking error generating means. Tracking offset adjustment means for adjusting the offset amount of the tracking error signal, equalization means for performing equalization processing on the tracking error signal output from the tracking error generation means, and tracking error subjected to equalization processing from the equalization means. Above based on the signal Driving means for driving the objective lens in a radial direction of the optical disc; and a tracking error signal output from the tracking error generating means, the tracking error signal being equivalent to one of a displacement in one direction and a displacement in another direction. A low-frequency component extracting means for extracting a low-frequency component; a polarity determining means for determining the polarity of a low-frequency component of the tracking error signal extracted by the low-frequency component extracting means; The tracking offset adjusting method in the optical disc apparatus provided with a first shift voltage for shifting the optical disc and a shift voltage generating means for generating a second shift voltage for shifting the outer circumferential direction of the optical disc, the tracking offset adjustment method includes: A first step of applying a first shift voltage from the shift voltage generating means to the driving means; A second step of applying a second shift voltage from the shift voltage generating means to the driving means, and a third step of detecting a polarity obtained from the polarity determining means during the application of the first and second shift voltages. And a fourth step of changing an offset amount in the tracking offset adjusting means according to the polarity obtained from the polarity determining means.