JPH0963078A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the correct detection of attendant information by changing the relative positional relation between an objective lens and an optical axis while applying an offset on the position sensor output of the objective lens to eliminate the asymmetry of a track signal being the output of a track signal arithmetic circuit. SOLUTION: In an optical disk device detecting attendant information, plural track light receiving elements detecting a diviation, a track signal arithmetic circuit 5a generating a track signal by the difference in output between I/V conversion circuits, a position sensor detecting the deviation of the objective lens from the neutral point of a track orthogonal direction, a position sensor arithmetic circuit 12 and an offset impressing means 13 applying the offset on the output of the position sensor are provided. Then, a wobble signal is detected from the output of the track signal arithmetic circuit 5a by changing the asymmetry of the track signal while changing an offset amount to be applied from the offset impressing means 13 according to the track signal being the output of the track signal arithmetic circuit 5a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc for detecting a reproduction signal RF on a track by causing a light beam to follow a track on the optical disc and detecting incidental information such as an address of the optical disc on which track wobble is recorded. The present invention relates to an apparatus, and more particularly, to an optical disk apparatus that enables accurate detection of incidental information.

[0002]

2. Description of the Related Art Generally, when detecting incidental information from an optical disk having a structure for recording incidental information in which a groove for tracking is wobbled, it is detected from a difference in light receiving element output for detecting a track signal. However, if there is an imbalance in the amount of light incident on the light receiving element for track signal detection, common mode noise cannot be sufficiently removed when the difference is taken,
There is a problem that the incidental information cannot be detected accurately.

That is, if there is no imbalance, the common-mode noise removal ratio becomes sufficiently large to allow accurate detection, but if imbalance occurs, it becomes difficult to perform accurate detection. Such a problem is particularly pronounced when the incidental information is detected in a recorded area of an optical disc for recording or reproducing data due to the intensity of reflected light such as CD-R, and the incidental information cannot be detected. In some cases, it cannot be done.

Needless to say, it is desirable to adjust the optical system so that an imbalance in light quantity does not occur, but there is a limit to the mechanical adjustment, and it may occur later due to changes with time or warpage of the media. The imbalance that is given is inevitable. As one method for solving such inconvenience, a reproduction signal RF is generated from a sum signal of two light receiving elements divided in the track tangential direction, and the two light receiving element outputs are normalized by the reproduction signal RF to obtain a normal signal. A method of detecting incidental information from the difference between the converted signals has been proposed (Japanese Patent Laid-Open No. 6-290462).

In this case, the reproduction signal RF is several 100K.
Although the signal band is higher than Hz, it is difficult to widen the band of a normalizing circuit (for example, a dividing circuit), and if such a circuit is intentionally constructed, there is a disadvantage that the cost is increased. In addition, since the reproduction signal RF is used for normalization, there is a problem that this circuit cannot be operated during the recording operation.

[0006]

As described in the prior art, generally, for detecting incidental information such as an address recorded by wobbling a tracking groove, for example, a pair of light receiving elements for detecting a track signal. It is detected from the output difference. In this case, if there is an imbalance in the amount of light incident on the light receiving element for track signal detection, common-mode noise cannot be sufficiently removed when the difference between the light receiving element outputs is taken.
There is a problem that the incidental information cannot be detected accurately.

[0007] Such a problem is particularly prominent when detecting incidental information in a recorded area of an optical disk for recording or reproducing data depending on the intensity of reflected light, like a CD-R. Conversely, if there is no such imbalance, the common-mode noise removal ratio can be made sufficiently large, and the incidental information can be accurately detected. According to the present invention, an offset is given to the output of the position sensor of the objective lens to change the relative positional relationship between the objective lens and the optical axis, thereby removing the asymmetry of the track signal output from the track signal calculation circuit. (Inventions of claims 1 to 13).

[0008]

According to a first aspect of the invention, focus control means for focusing a light beam from a semiconductor laser on an optical disk by an objective lens, track control means, and moving the objective lens in a radial direction of the optical disk. In the optical disk device, which is provided with a carriage servo means for causing the light beam to follow the track on the optical disk to detect the reproduction signal on the track and to detect the incidental information of the track-wobble-recorded optical disk. A plurality of track light receiving elements for detecting the deviation of the light flux from the track center, an I / V conversion circuit for converting the output from the track light receiving elements into a current / voltage, and an I / V
A track signal calculation circuit that generates a track signal based on the difference in the output from the conversion circuit, a position sensor that detects the deviation from the neutral point of the objective lens in the direction orthogonal to the track, and a position sensor calculation circuit that calculates the output from the position sensor. And an offset applying means for applying an offset to the output of the position sensor, and the asymmetry of the track signal is changed by changing the offset amount applied from the offset applying means in accordance with the track signal output from the track signal arithmetic circuit. The wobble signal is detected from the output of the track signal calculation circuit.

According to a second aspect of the present invention, in the optical disc device according to the first aspect, the offset application amount given to the output of the position sensor is determined so that the asymmetry of the track signal in the state where the focus servo is applied is minimized. There is.

According to a third aspect of the present invention, in the optical disc device according to the first aspect, the step jump executing means is provided, and the offset application amount given to the output of the position sensor performs step jump from the track-on state, It is determined so that the asymmetry of the track signal is minimized.

According to a fourth aspect of the present invention, in the optical disk device according to the first aspect, the reproduction signal mixing amount detecting means for detecting the mixing amount of the reproduction signal into the track signal is provided, and the offset application amount given to the output of the position sensor is , It is determined so that the mixing of the reproduced signal with the track signal in the track-on state is minimized.

According to a fifth aspect of the invention, in the optical disc device according to the first to fourth aspects, the amount of offset applied to the output of the position sensor is changed depending on the radial position of the optical disc.

According to a sixth aspect of the invention, in the optical disk device according to the first to third or fifth aspects, the offset is applied during the reproducing operation and the offset is not applied during the recording operation.

According to a seventh aspect of the present invention, in the optical disk device of the first to third or fifth aspects, the offset during the reproducing operation is determined by the output of the track signal arithmetic circuit when the high frequency superposition is on, and the recording operation is being performed. The offset of is determined by the output of the track signal operation circuit when the high frequency superposition is off.

According to the invention of claim 8, in the optical disk device of claims 1 to 7, the offset is not applied when the incidental information is not detected.

According to a ninth aspect of the invention, in the optical disk device according to the first to eighth aspects, the amount of offset to be applied is limited.

According to a tenth aspect of the invention, in the optical disc device according to the first to ninth aspects, the offset amount to be applied is adjusted when the power is turned on or when the optical disc is inserted.

According to an eleventh aspect of the invention, in the optical disk device according to the first to tenth aspects, a temperature detecting means is provided, and the offset amount to be applied is readjusted according to the temperature change.

According to a twelfth aspect of the present invention, in the optical disk device according to the first to tenth aspects, the offset amount to be applied is readjusted at predetermined time intervals.

According to a thirteenth aspect of the present invention, in the optical disc apparatus of the first to tenth aspects, the offset amount to be applied is readjusted immediately before the data recording or reproducing operation.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to an optical disc device for detecting incidental information such as an address of an optical disc on which track wobble recording is performed, and more specifically, it realizes an optical disc device which enables accurate detection of incidental information. The invention of claim 1 is the basic invention, and the inventions of claims 2 to 13 are all based on the invention of claim 1. First, an example of the overall configuration of the optical disc device of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of the optical disk device of the present invention. In the figure, 1 is an optical disk, 2 is a spindle motor, 3 is an optical pickup, 4 is focus control means, 4
a is a focus signal arithmetic circuit, 5 is track control means,
5a is a track signal operation circuit, 6 is a carriage servo means, 7 is a preamplifier section, 8 is an addition circuit, 9 is a servo controller, 10 is an asymmetry detecting means, and 11 is a CP.
U and 12 are position sensor arithmetic circuits, 13 is an offset applying means, FE is a focus error signal, and TE.
Indicates a track error signal, and RF indicates a reproduction signal.

The structure and operation of the optical disk device shown in FIG. 1 are as follows. The optical disc 1 is rotationally driven by a spindle motor 2. Optical pickup 3
Includes a semiconductor laser, an optical system, a focus actuator, a track actuator, a four-division light receiving element, and a position sensor (not shown), and irradiates the optical disc 1 with laser light. This optical pickup 3
Receives the reflected light from the optical disc 1 and gives its output to the focus control means 4 and the track control means 5 via the preamplifier section 7 in the next stage.

The focus control means 4 produces a focus error signal FE from the received light receiving signal, and the track control means 5 similarly produces a track error signal TE from the light receiving signal. Further, the reproduction signal RF of the optical disc 1 is generated by giving the output of the preamplifier section 7 to the addition circuit 8 and adding them. The preamplifier section 7 shown in FIG. 1 has the following configuration.

FIG. 2 is a circuit diagram showing an example of the detailed configuration of the preamplifier section 7 and its peripheral circuits in FIG. Reference numerals in the figure are the same as those in FIG.
22D indicates an I / V conversion circuit, and Vref indicates a reference voltage.

As shown in FIG. 2, the preamplifier section 7 corresponds to the four-divided light receiving elements 21A to 21D and corresponds to the I / V.
The conversion circuits 22A to 22D are composed of a total of four I / V conversion circuits. That is, the four-division light receiving elements 21A to 2
1D output corresponds to the corresponding I / V conversion circuit 22A
22D, the current-voltage conversion is performed, and the current-voltage conversion is applied to the next-stage track signal operation circuit 5a and focus signal operation circuit 4a.

In the track signal operation circuit 5a and the focus signal operation circuit 4a, the I / V conversion circuits 22A to 22D are provided.
The output of is calculated. As shown in FIG. 1, the track signal calculation circuit 5a is built in the track control means 5, and the focus signal calculation circuit 4a is built in the focus control means 4.

Then, as shown in FIG. 1, the reproduction signal RF generated by the focus signal arithmetic circuit 4a in the focus control means 4 has a phase correction circuit (not shown) and a drive for stabilizing the servo system. It is output as a control signal to the focus actuator of the optical pickup 3 via an amplifier (not shown). The focus servo system has such a configuration. The same applies to the track servo system, which is a reproduction signal RF generated by the track signal arithmetic circuit 5a in the track control means 5.
Is output as a control signal to the track actuator of the optical pickup 3 via a phase correction circuit (not shown) and a drive amplifier (not shown) for stabilizing the servo system.

The focus control means 4 and the track control means 5 are controlled by the servo controller 9. The reproduction signal RF is also supplied to the carriage servo means 6 via a phase correction circuit (not shown) and a drive amplifier (not shown),
These constitute a carriage servo system for moving the optical pickup 3 in the radial direction of the optical disc 1.
The optical pickup 3 will be described below with reference to FIGS. 3 and 4.

FIG. 3 is an exploded perspective view showing the main structure of the optical system provided inside the optical pickup 3. In the figure, the four-division light receiving element 21 is the same as that in FIG. 2, 31 is an aspherical objective lens, 32 is a quarter wavelength plate, 33 is a deflection prism, 34 is a collimating lens, 3
5 is a polarization beam splitter, 36 is a cylindrical lens, 37 is a semiconductor laser, and 38 is a high frequency superposition module.

FIGS. 4A and 4B are views showing the main structure of the optical system of the optical pickup 3 shown in FIG. 3, in which FIG. 4A is a side view and FIG. . The reference numerals in the figure are the same as those in FIG. 3, and 21A to 21D indicate the respective light receiving elements of the four-division light receiving element 21.

The light emitted from the semiconductor laser 37 is incident on the polarization beam splitter 35. At this time, since the deflection direction of the laser light is the vertical direction, 100% of the laser light that has entered the polarization beam splitter 35 enters the collimator lens 34. Since the collimator lens 34 converts the diffused light into parallel light, the deflection prism 33 has
The vertically polarized parallel light is incident.

The laser light reflected by the deflection prism 33 passes through the aspherical objective lens 31 via the quarter-wave plate 32 and enters the optical disc 1. After passing through the quarter-wave plate 32, the polarization direction of the laser light becomes circularly polarized light, and the reflected light from the optical disk 1 becomes circularly polarized light in the opposite direction and enters the quarter-wave plate 32 again. This quarter wave plate 3
After passing through 2, the light has a horizontal polarization direction and is incident on the polarization beam splitter 35 via the collimator lens 34.

In this state, since the polarization direction is horizontal, 100% of the incident light is the cylindrical lens 36.
To the four-division light receiving element 21. As shown in the front view (light receiving surface) of FIG. 4 (2), the four-divided light receiving element 21 is composed of four light receiving elements A to D. This 4
The divided light receiving element 21 corresponds to the four divided light receiving elements 21A to 21D shown in FIG.

Here, each element A of the four-division light receiving element 21
D (corresponding to the four-division light receiving elements 21A to 21D in FIG. 2) output (based on the amount of incident light)
, The generated focus error signal FE, track error signal TE, and reproduction signal RF can be expressed by the following equations. The circuit for generating the reproduction signal RF is not shown. Signal FE = (A + C)-(B + D) Signal TE = (A + B)-(C + D) Signal RF = A + B + C + D

Next, the position sensor built in the optical pickup 3 will be described in detail. At first,
The objective lens provided in the optical pickup 3 will be described. Next, FIG. 5 shows the structure of the known aspherical objective lens 31 shown in FIGS. 3 and 4 above.

FIG. 5 shows the aspherical objective lens 31.
It is a figure which shows the principal part structure. In the figure, 41 is a lens holder, 42 is a support spring, 43 is a support spring fixing member,
44 is a slit, 45 is a light emitting diode (LED), 4
6A and 46B are a pair of light receiving elements, 47 is a lens position sensor housing, and arrow P is the moving direction of the lens holder 41.

The aspherical objective lens 31 shown in FIG.
It is configured to be movable in a direction perpendicular to the paper surface (optical axis direction) and a direction indicated by an arrow P (direction perpendicular to the optical axis).
The reason why the movement in the optical axis direction is possible is to collect the light emitted from the aspherical objective lens 31 onto the optical disk (1 in FIG. 1) placed horizontally with respect to the paper surface. Further, the movement in the direction of the arrow P is to follow the light condensed on the track on the optical disk.

This aspherical objective lens 31 is supported by a lens holder 41, and the lens holder 41 has a support spring 42,
It is held by the support spring fixing member 43. Also,
The slit 44 is fixed to the lens holder 41, and a part of the light emitted from the light emitting diode 45 is received by the light receiving element 4.
6A, 46B are arranged so as to be incident on 6A, 46B, and the amount of light incident on the pair of light receiving elements 46A, 46B changes according to the movement of the lens holder 41 in the direction of arrow P, and the aspherical objective lens 31 The amount of movement in the direction of arrow P can be detected.

The structure including the light emitting diode 45 and the light receiving elements 46A and 46B is used as a lens position sensor,
Alternatively, it is called a position sensor. The positional relationship of this lens position sensor is fixed by a lens position sensor housing 47. Next, slit 4
4 and the lens position sensor will be described.

FIG. 6 is a view for explaining the positional relationship between the slit 44 shown in FIG. 5 and the lens position sensor. (1) shows the case where the slit 44 is in the normal position, and (2) shows the slit 44.
Is a diagram showing a case where the slit 44 moves in the direction of the arrow Q, and (3) is a diagram showing a case where the slit 44 moves in the direction of the arrow R. Reference numerals in the drawing are the same as those in FIG. 5, LB indicates laser light, and arrows Q and R indicate the moving direction of the slit 44.

As described above, the lens position sensor (position sensor) includes the light emitting diode 45 and the light receiving elements 46A and 46B. In the normal state (when the aspherical objective lens 31 is not moved), the slit 44 is at the position shown in FIG. 6 (1).
When the slit 44 moves to the right (the direction of arrow Q), the relationship shown in FIG. 6 (2) is obtained.

On the contrary, when the slit 44 moves leftward (in the direction of arrow R), the relationship shown in FIG. 6 (3) is obtained.
Therefore, the laser light LB emitted from the light emitting diode 45 is received by the light receiving element 46 according to the position of the slit 44.
The amount of light incident on A and 46B changes. Therefore, the displacement of the slit 44 (the position of the aspherical objective lens 31) can be known by detecting the amount of light incident on the pair of light receiving elements 46A and 46B. Next, a position calculation circuit using this lens position sensor will be described.
In the following description, this lens position sensor is referred to as a position sensor.

FIG. 7 is a functional block diagram showing a configuration example of the position sensor arithmetic circuit 12 shown in FIG. Reference numerals in the drawing are the same as those in FIG. 5, 51 is a position sensor, 52A and 52B are I / V conversion circuits, 53 is an addition circuit, 54 is a subtraction circuit, and 55 is an integration circuit.

The position sensor arithmetic circuit 12 shown in FIG. 7 is an arithmetic circuit for calculating the light receiving output from the pair of light receiving elements 46A and 46B of the position sensor 51, that is, the lens position sensor shown in FIG. First, I / V
The conversion circuit 52A converts the current output from one light receiving element 46A into a voltage, and the I / V conversion circuit 52B converts the current output from the other light receiving element 46B into a voltage. Then, the subtraction circuit 54 uses the two I / V conversion circuits 5
The voltages output from 2A and 52B are subtracted.

On the other hand, the adder circuit 53 similarly has two I /
The voltages output from the V conversion circuits 52A and 52B are added. The integrating circuit 55 integrates the output from the adding circuit 53, and controls the light emitting diode (LED) 45 so that the amount of light input to the pair of light receiving elements 46A and 46B becomes constant. Give a control signal. The position sensor arithmetic circuit 12 is configured as described above.

The offset applying means 13 is, for example, D / A.
A DC offset is given to the subtraction circuit 54 in the position sensor arithmetic circuit 12 by a signal from the CPU (central processing unit) 11 shown in FIG.
In this case, the CPU 11 applies the offset voltage from the track error signal TE shown in FIG. Specifically, while changing the offset voltage, the change in the asymmetry of the track error signal TE is observed, and when the asymmetry becomes a predetermined value or less, the offset voltage at that time is supplied, and thereafter, the fobble signal (address Incidental information such as
Hereinafter, simply referred to as a fobble signal).

Here, the meaning of giving an offset voltage and
The asymmetry of the track error signal TE will be described. First, the offset voltage will be described. When the track servo is applied, the subtraction circuit 54 outputs the output of the position sensor 51 corresponding to the eccentricity of the optical disc 1. And the position sensor 5
Since the carriage servo is applied so that the output of 1 becomes "0", applying the offset voltage by the offset applying means 13 has the same result as shifting the optical axis.

Next, asymmetry will be described. Regarding the outputs of the four-divided light receiving elements 21A to 21D shown in FIG. 2 and FIG. 4, the (sum of light amounts incident on the light receiving elements 21A and 21B) and (sum of light amounts incident on the light receiving elements 21C and 21D) There is a difference between. This state is shown in FIG. 8 below.

FIG. 8 is a timing chart showing an example of the variation state of the track error signal TE. In the figure, the horizontal axis represents time, the vertical axis represents the signal TE, and Vref represents the reference voltage.

The track error signal TE shown in FIG.
Shows a signal waveform in a state where focus servo is applied by the focus control means 4 in FIG. 1 and track servo is not applied. As shown in FIG. 8, there is a difference between the amplitude above the reference voltage Vref of the track error signal TE and the amplitude below it. This is called asymmetry.

FIG. 9 is a diagram showing the relationship between the intensity distribution of the amount of light incident on the light receiving surfaces of the four-division light receiving elements 21A to 21D and the asymmetry. (1) shows the case where the spot center is on the left side of the light receiving surface. (2) shows the case where the spot center coincides with the center of the light receiving surface, and (3) shows the case where the spot center is on the right side of the light receiving surface.

In FIG. 9, in the four-divided light-receiving elements 21A to 21D shown in FIG. 4, the circle in each light-receiving element indicates the spot received at the time of detecting the fobble signal. Further, the track error signal TE shown below shows the track error signal in the state where the focus servo is applied and the track servo is not applied. Even if the spot is irradiated in the middle of the four-division light receiving elements 21A to 21D, the intensity distribution of the received light amount is not uniform.

For example, in FIG. 9A, the intensity distribution of the spot is large on the left side of the four-divided light receiving elements 21A to 21D, that is, on the side of the light receiving elements 21A and 21B, and on the right side, that is, on the side of the light receiving elements 21C and 21D. The asymmetry at time is shown. The track error signal TE of FIG. 9 (1) is the output of the track signal operation circuit 5a of FIG. 2 and has a large amplitude on the upper side of the reference voltage Vref and a small amplitude on the lower side. On the other hand, in FIG. 9 (3), the state of the intensity distribution of the spot is reversed, and the four-division light receiving elements 21A to 21D are shown.
5A shows asymmetry when the left side (light receiving elements 21A and 21B side) is small and the right side (light receiving elements 21C and 21D side) is large.

In this case, the track error signal TE has a small amplitude on the upper side and a large amplitude on the lower side of the reference voltage Vref. Further, FIG. 9 (2) shows a case of an ideal spot intensity distribution. In the case of FIG. 9 (2), the left side of the four-division light receiving elements 21A to 21D (light receiving elements 21A, 2
Since the amounts of light received on the 1B side) and on the right side (the light receiving elements 21C and 21D sides) are equal, the asymmetry is in the best state. In this case, the track error signal T
In E, the upper side amplitude and the lower side amplitude of the reference voltage Vref are equal.

9 (1) to 9 (3), variations in sensitivity of the light receiving elements 21A to 21D, variations in current / voltage conversion of the I / V conversion circuits 22A to 22D in FIG. 2 and track signals. Variations and the like of the arithmetic circuit 5a are ignored.
The case where the intensity distribution of the light amount received by the four-division light receiving elements 21A to 21D is not uniform has been described above. in this way,
Even if the intensity distribution of the amount of received light is small enough to ignore the variation, each of the light receiving elements 21A to 21D.
Of the sensitivity of the I / V conversion circuits 22A to 22D at the time of current / voltage conversion, and the track signal calculation circuit 5a.
The asymmetry as described above also occurs due to the variation of the. Asymmetry may also occur due to variations in spot positions.

As described above, since asymmetry is caused by various causes, it cannot be kept in the best state as shown in FIG. 9 (2) in all cases. By the way, this asymmetry calculates the amplitude of the upper side and the amplitude of the lower side of the reference voltage Vref with respect to the track error signal TE shown in FIGS. It can be detected by converting it with a converter or the like and outputting it as digital data to the CPU 11.

Embodiment of the Invention of Claim 1 As described above, the invention of claim 1 is the basic invention. In the optical disk device of the present invention, as shown in FIG.
For the track error signal TE shown in (3), if the upper side amplitude and the lower side amplitude of the reference voltage Vref are calculated, the calculation result is converted by an A / D converter or the like and output to the CPU 11 as digital data. However, by detecting asymmetry and removing its influence, it is possible to accurately detect a fable signal (supplementary information such as an address). Therefore, in the optical disc apparatus for detecting the incidental information of the track-fobble-recorded optical disc shown in FIG. 1, a plurality of track light-receiving elements (four divisions in FIG. 2) for detecting the deviation of the condensed light flux from the track center. Light receiving elements 21A-2
1D), the I / V conversion circuits (I / V conversion circuits 22A to 22D in FIG. 2) for converting the outputs from these track light receiving elements into current / voltage, and the difference between the outputs from these I / V conversion circuits. And a position sensor (5 in FIG. 7) for detecting a deviation from the neutral point of the objective lens in the direction perpendicular to the track.
1), a position sensor calculation circuit (12) for calculating the output from the position sensor, and an offset applying means (1) for giving an offset to the output of the position sensor.
3) is provided, the asymmetry of the track signal is changed by changing the offset amount given by the offset applying means in accordance with the track signal output from the track signal calculation circuit, and the fobble is output from the output of the track signal calculation circuit. The signal is detected (the invention of claim 1).

FIG. 10 is a flow chart showing the main processing flow when the offset amount is set in the optical disk device of the present invention. In the figure, # 1 to # 7 indicate steps.

This control is performed by the CPU 11. In step # 1, the CPU 11 rotationally drives the spindle motor 2 by a spindle motor driver (not shown). In step # 2, the semiconductor laser is turned on by the driver circuit of the semiconductor laser (37 in FIG. 3).

In step # 3, the servo controller 9 is instructed and the focus control means 4 activates the focus servo. In step # 4, the asymmetry detecting means 10 detects asymmetry from the track error signal TE. In step # 5, it is determined whether the detected asymmetry has the minimum value.

If the asymmetry has not reached the minimum value, the flow advances to step # 6 to apply the offset by the offset applying means 13. Then, in step # 5,
When it detects that the asymmetry is at the minimum value,
Go to step # 7. In step # 7, the CPU 11
The offset value when the asymmetry becomes the minimum value,
This is given to the position sensor arithmetic circuit 12, and the flow of FIG. 10 is terminated.

Embodiment 2 of the Invention of Claim 2 The invention of claim 2 has the same hardware configuration as that of the invention of claim 1, and the optical disk device having the configuration of FIG. 1 invention). In the optical disk device of FIG. 1, the offset application amount of the offset application unit 13 is the minimum asymmetry when the focus control unit 4 performs focus servo (in FIG. 8 and FIG. It is characterized in that it is determined so that the difference from the side amplitude is minimum).

The control performed by the CPU 11 is similar,
This is executed according to the flowchart shown in FIG. According to the invention of claim 2, in the optical disk device of claim 1 described above, the track signal is detected in a state where focus servo is applied, and the relative positional relationship between the objective lens and the optical axis is changed, The asymmetry of the track signal is minimized. Therefore, it is possible to more accurately remove the asymmetry of the track signal as compared with the optical disk device according to the first aspect, and it is possible to more accurately detect the incidental information.

Embodiment 3 of the Invention of Claim 3 In the invention of claim 2 described above, the track signal is detected with only the focus servo applied, and the asymmetry of the track is measured. In this case, there is a possibility that the focused light beam crosses the track, causing fluctuations in the focus signal and defocusing, and it may not be possible to accurately remove the asymmetry. . The invention of claim 3 has the same hardware configuration as that of the invention of claim 1 described above, and is premised on the optical disk device having the configuration of FIG. 1 described above (the invention of claim 1).

According to the invention of claim 3, in the optical disk device of claim 1, the asymmetry is the minimum when the track servo is applied by the track control means 5 (see FIG. 8).
9 and FIG. 9 is characterized in that the difference between the amplitude above the reference voltage and the amplitude below the reference voltage is the minimum).
As described above, in the third aspect of the invention, in the optical disc apparatus of the first aspect, the step jump is performed, and the track signal is measured in that state to minimize the asymmetry.

FIG. 11 is a timing chart showing an example of the fluctuation state of the track error signal TE at the moment when the step jump is performed. The horizontal axis of the figure is the time, and the vertical axis is the signal T.
E is shown.

Since the track error signal TE at the moment of performing the step jump traverses the track, this FIG.
It changes as shown in 1. By measuring the asymmetry at this point, it is possible to obtain the offset application amount that minimizes the asymmetry without being affected by the fluctuation of the focus signal.

FIG. 12 is a flow chart showing the main processing flow when setting the offset amount in the optical disk device of the third aspect of the invention. In the figure, # 11 to # 1
8 indicates a step.

This control is also performed by the CPU 11. Step # 11 executes steps # 1 to # 3 of the flowchart shown in FIG. That is, CPU1
1 drives the spindle motor 2 to rotate (step # 1 in FIG. 10) and turns on the semiconductor laser (step # 1).
2) Further, the focus controller 4 is instructed to apply the focus servo by the focus control means 4 (step # 3).

At step # 12, the servo controller 9
The track control means 5 makes a step jump. In step # 13, the asymmetry detecting means 10 detects asymmetry from the track error signal TE. In step # 14, it is determined whether the detected asymmetry has the minimum value.

When the asymmetry is not the minimum value, the process proceeds to step # 16, and the offset applying means 13 applies the offset. And step # 15
Then, when it is detected that the asymmetry is the minimum value, the process proceeds to step # 17. In step # 17, the CPU
11 calculates the offset value at the time when the asymmetry becomes the minimum value. When the offset value is obtained, the offset value is given to the position sensor arithmetic circuit 12 by the offset applying means 13.

In step # 18, the CPU 11 instructs the servo controller 9 to end the step jump by the track control means 5 to bring the track servo state and to end the flow of FIG. Through the processing in steps # 11 to # 18 described above, the track signal in the state where the step jump is performed is measured, and the offset value that provides the minimum asymmetry is obtained. Therefore, the asymmetry of the track signal can be removed without being affected by the focus fluctuation, and the incidental information can be detected more accurately.

According to a fourth aspect of the present invention, in the optical disc device according to the fourth aspect, in the optical disc device according to the first aspect, the reproduction signal RF mixing amount detection means is provided, and the mixing amount of the reproduction signal RF into the track signal is minimum. As described above, the characteristic is that the relative positional relationship between the objective lens and the optical axis is changed.

FIG. 13 is a diagram showing a waveform example for explaining a state in which the reproduction signal RF is mixed in the wobble signal. (1) is a normal wobble signal (a state in which the reproduction signal RF is not mixed), (2) ) Is the wobble signal mixed with the reproduction signal RF, (3)
Indicates the mixed reproduction signal RF.

The wobble signal is 4 when reproducing at double speed.
4.1KHz ± 2KHz (hence 42.1KHz-4
The signal is FM-modulated by the address supplementary information at 6.1 KHz) and has an amplitude of about 100 mVpp. On the other hand, since the reproduction signal RF has a large amplitude of about 1 Vpp, it tends to affect the wobble signal. In addition, mV
pp and Vpp indicate voltages between positive and negative peak values.

For example, as shown in FIG. 13 (1), when the reproduction signal RF is mixed in with the normal wobble signal, FIG. 13 (2)
Distortion occurs in the waveform like. The mixed reproduction signal RF in this case is shown in FIG. 13 (3). The frequency of the reproduction signal RF is 785 KHz (EF
Equivalent to 11T by M modulation: EFM modulation is EIGHT TO
FORTEEN MODURATION method) -2.8
The signal frequency is 8 MHz (equivalent to 3T by EFM modulation).
Next, a circuit for extracting only the reproduction signal RF from the wobble signal mixed with the reproduction signal RF as shown in FIG. 13B will be described.

FIG. 14 is a functional block diagram showing an embodiment of a circuit for extracting the reproduction signal RF mixed in the wobble signal in the optical disk device of the fourth aspect of the invention. Reference numerals in the figure are the same as those in FIG. 1, 61 is a high-pass filter, 62 is a peak hold circuit, 63 is an A / D conversion circuit, and 64 is a CPU.

The high-pass filter 61 is a filter that passes only the high frequency component of the track error signal TE output from the track signal calculation circuit 5a shown in FIG. For example, as shown in FIG. 13 (2), when a waveform mixed with the reproduction signal RF is input, only the mixed reproduction signal RF is passed. Since the wobble signal is 46.1 KHz (maximum) during double speed reproduction, if the cutoff frequency is set to about 500 KHz, the wobble signal can be blocked and only the reproduction signal RF can be passed.

The reproduction signal RF that has passed through the high pass filter 61, that is, the reproduction signal RF component mixed in the wobble signal is processed by the peak hold circuit 62 in the next stage.
The amplitude value is retained. The held value is A /
The analog value is converted into a digital value by the D conversion circuit 63, and the converted digital value is output to the CPU 64.

The CPU 64 changes the offset amount by the offset applying means 13 shown in FIG. 1 according to the output value of the A / D conversion circuit 63, and minimizes the reproduction signal RF component mixed in the wobble signal. Find an offset value like this. By setting the offset value thus obtained in the offset applying means 13, the asymmetry is improved. As a result, optimum wobble signal detection becomes possible. The above operation is shown in the flow.

FIG. 15 is a flow chart showing the main processing flow when setting the offset amount in the fourth embodiment of the present invention. In the figure, # 21 to # 26 indicate steps.

This overall control is also performed by the CPU 1 shown in FIG.
1 is performed. Step # 21 is the same as steps # 1 to # 3 in FIG. 10, and the CPU 11 causes the spindle motor 2 to rotate and drive by the spindle motor driver (not shown) and the driver circuit (not shown) of the semiconductor laser 37. The semiconductor laser 37 (FIG. 3) is turned on. In addition, the servo controller 9
The focus control means 4 activates the focus servo.

At step # 22, the CPU 11 instructs the servo controller 9 to apply the track servo by the track control means 5. In step # 23, the mixing amount of the reproduction signal RF is detected by the reproduction signal RF mixing amount detecting means shown in FIG.

At step # 24, it is checked whether or not the mixing amount of the reproduction signal RF is minimized. In this case, the offset that minimizes the mixed amount is obtained by a known difference method algorithm.

At the next step # 25, the offset applying means 13 applies the offset. If the mixing amount of the reproduction signal RF is not the minimum, the process returns to the previous step # 23 to detect the mixing amount of the reproduction signal RF.
Then, when it is detected in step # 24 that the mixing amount of the reproduction signal RF is minimum, the CPU 11 determines the offset amount when the mixing amount of the reproduction signal RF is minimum in the position sensor in step # 26. It is given to the arithmetic circuit 12.

By the processing of steps # 21 to # 26 described above, the relative positional relationship between the objective lens and the optical axis is changed so that the mixing amount of the reproduction signal RF into the track signal is minimized. Therefore, it is possible to detect the incidental information more accurately as compared with the optical disc device according to the first aspect.

Embodiment of the Invention of Claim 5 The invention of claim 5 aims to eliminate the influence of warpage or the like that occurs in the optical disk, and the inventions of claims 1 to 4 described so far. All can be applied. According to a fifth aspect of the present invention, in the optical disc apparatus according to the first to fourth aspects, the amount of offset applied to the output of the position sensor is changed depending on the radial position of the optical disc.

FIG. 16 is a side view showing an example of a state in which a warped optical disk is set in the apparatus. The reference numerals in the figure are the same as those in FIG. 1, and 3'denotes the moving position of the optical pickup 3.

Although the warp of the optical disc 1 is emphasized in FIG. 16, microscopically, almost all the optical discs 1 have such a tilt (tilt: hereinafter referred to as tilt). There is. Therefore, depending on the radial position of the optical disc 1, the amount of light incident on each of the light receiving elements A to D of the four-division light receiving element of the optical pickup 3 changes as shown in FIG.

Therefore, it is necessary to change the applied amount to the position sensor arithmetic circuit 12 output from the offset applying means 13, that is, the offset amount, according to the radial position on the optical disc 1. By performing such control, the wobble signal can be detected regardless of the tilt generated on the optical disc 1.

More specifically, the CPU 11 detects the position on the optical disk 1 in the radial direction in the state where the focus control means 4 applies the focus servo and the track control means 5 applies the track servo. The position in the radial direction can be detected by a wobble signal,
It is also possible to detect by reproducing the subcode recorded on the optical disc 1 as the reproduction signal RF. The radial position on the optical disc 1 is set to a predetermined value (here, 10 minutes, 30 minutes according to ISO,
At 60 minutes), the offset adjustment is performed by the method described in the embodiments of claim 2 and claim 3. In the following flow, the offset adjusting method is the step jump method described in the invention of claim 3, but it goes without saying that the adjusting method described in the invention of claim 2 can also be used.

FIG. 17 is a flow chart showing the main processing flow when the offset amount is set in the fifth embodiment of the present invention. In the figure, # 31 to # 42 indicate steps.

This control is also performed by the CPU 11. Step # 31 is the same as steps # 1 to # in FIG.
3, the CPU 11 rotationally drives the spindle motor 2 by a spindle motor driver (not shown), and turns on the semiconductor laser 37 (FIG. 3) by a driver circuit (not shown) of the semiconductor laser 37. Further, a command is given to the servo controller 9, and the focus servo is applied by the focus control means 4.

At step # 32, the CPU 11 commands the servo controller 9 to apply the track servo by the track control means 5. In step # 33, CPU1
1 detects the position on the optical disc 1 in the radial direction. In step # 34, a predetermined position (for example, 10
Min) is accessed.

When a predetermined position (for example, 10 minutes according to ISO) is accessed, the process proceeds to step # 35, and the CPU
Reference numeral 11 instructs the servo controller 9 to perform a step jump by the track control means 5. Step # 3
At 6, the asymmetry detecting means 10 detects the asymmetry from the track error signal TE. Step #
At 37, it is determined whether the detected asymmetry has the minimum value.

When the asymmetry is not the minimum value, the process proceeds to step # 38, and the offset applying means 13 applies the offset. And step # 37
Then, when it is detected that the asymmetry is the minimum value, the process proceeds to step # 39. In step # 39, the CPU
Reference numeral 11 gives the offset value when the asymmetry becomes the minimum value to the position sensor arithmetic circuit 12 by the offset applying means 13.

The process proceeds to step # 40 to end the step jump, and the track servo state is set. Then, the process returns to step # 33, and the same processing is repeated. In the previous step # 34, a predetermined position (for example, 10
If it is not accessed as a result of checking whether or not (Min) is accessed, the process proceeds to step # 41. In step # 41, it is checked whether a predetermined position (for example, 30 minutes according to ISO) has been accessed.

When a predetermined position (for example, 30 minutes according to ISO) is accessed, the process proceeds to step # 35, and when not accessed, the process proceeds to step # 42. Similarly in step # 42, it is checked whether or not a predetermined position (for example, 60 minutes according to ISO) has been accessed.

By the above processing, the optical disc 1
The wobble signal can be detected regardless of the tilt of. Therefore, the influence of the warp of the optical disc is removed, and the incidental information can be accurately detected.

Embodiment 6 of the Invention of Claim 6 In the optical disk device of claim 6, the inventions of claims 1 to 3
Alternatively, the optical disk device of the fifth aspect is characterized in that the offset is applied during the reproducing operation and the offset is not applied during the recording operation. Since there are many points in common with the optical disk device of claim 7, the related points will be described together. Generally, in a writable optical disc, high frequency superposition is performed in order to reduce the noise level of a semiconductor laser which is a light source.

However, in the high frequency superimposition, the peak power of the semiconductor laser exceeds the maximum rating during the recording operation. Therefore, it is necessary to turn off the high frequency superposition during recording. The problem in this case is that the track asymmetry changes when high frequency superimposition is not performed. It should be noted that this problem similarly occurs during reproduction operation (not only during reproduction of data but also during focus servo operation or seek operation) and during recording operation, and the track asymmetry changes.

As described above, when the asymmetry changes during recording and during reproduction, the position sensor output is taken into consideration in the optical disk device according to any one of claims 1 to 3 or 5 without considering ON / OFF of high frequency superposition. If the amount of offset application that gives the value is determined, in some cases, it becomes difficult to detect the incidental information at the time of recording.

FIG. 18 is a diagram showing a track error signal TE in a state where focus servo is applied and track servo is not applied. (1) shows a waveform when the high frequency superposition is off, and (2) shows a waveform when the high frequency superposition is on. Show.

The track error signal TE is the output of the track signal operation circuit 5a shown in FIG.
The output is centered around f. First, FIG.
(2) is the track error signal TE when the light output from the semiconductor laser 37 is subjected to high frequency superposition (on) in the high frequency superposition module 38 shown in FIG. On the other hand, FIG. 18 (1) shows the track error signal TE when the high frequency superimposition is not applied (OFF).

As is clear from FIGS. 18 (1) and 18 (2), there is a difference in the asymmetry when the high frequency superposition is on and when the high frequency superposition is off. Normally, when writing information on the optical disc 1, the high frequency superimposition is turned off, and when reproducing the written information, the high frequency superposition is turned on. The reason is,
From the viewpoint of reducing the noise of the semiconductor laser 37, it is preferable to turn on the high frequency superposition. However, when writing (recording) is performed with the high frequency superimposition turned on,
The life of the semiconductor laser 37 is adversely affected.

Therefore, a control for turning off the high frequency superimposition at the time of writing information and turning on the high frequency superposition at the time of reproducing the information is used. Therefore, it is necessary to change the offset amount output from the offset applying unit 13 between recording and reproducing.

FIG. 19 is a functional block diagram showing an embodiment of the wobble signal detection circuit at the time of recording on the optical disc 1 in the optical disc apparatus of the invention of claim 6. Reference numerals in the figure are the same as those in FIG. 2, 71 is a sample hold switching signal generating means, 72A to 72D are sample hold switching switches, and 73A to 73D are sample hold circuits.

In FIG. 19, the preamplifier section 7, the track signal operation circuit 5a, and the four-divided light receiving elements 21A to 21 are used.
D is the same as in FIG. Then, at the time of recording on the optical disc 1, the sample hold switching signal generating means 7 is provided between the preamplifier section 7 and the track signal arithmetic circuit 5a.
There are provided sample and hold changeover switches 72A to 72D and sample and hold circuits 73A to 73D which are controlled to be switched by a signal from 1.

More specifically, in the sample hold switch 72A (same for 72B to 72D), the output of the four-division light receiving element 21A (21B to 21D) is the preamplifier section 7.
This is a switch for sample-holding the current-voltage converted signal by the sample-hold circuit 73A (73B to 73D) in the next stage. At the time of recording, the sample hold changeover switches 72A to 72D shown in FIG.
Is controlled by a signal from the sample hold switching signal generating means 71.

Sample hold switching signal generating means 71
Generates a pulse signal, and turns off the sample-and-hold changeover switches 72A to 72D at the time of recording. Therefore, the voltages sampled and held by the sample-and-hold circuits 73A to 73D at the next stage are supplied to the track signal operation circuit 5a. Is entered. The wobble signal at the time of recording is not affected by asymmetry as compared with that at the time of reproduction, because no pit is written on the optical disc 1. Therefore, the offset applying unit 1 is used in consideration of asymmetry during recording.
Even if the offset voltage is not applied to the position sensor arithmetic circuit 12 by 3, the wobble signal can be detected.

When an offset voltage is applied to the position sensor arithmetic circuit 12 by the offset applying means 13, the high frequency superimposition is off during recording.
In consideration of the fact that the high frequency superimposition is different from the asymmetry when the high frequency superposition is off (reproducing), the offset amount may be determined from the output of the track signal operation circuit 5a when the high frequency superimposing is off (reproducing). invention). The method of applying the offset voltage to the position sensor arithmetic circuit 12 by the offset applying means 13 is the same as the method already described.

The CPU 11 controls the optical disk 1 such as a write command from an initiator (for example, a host computer).
When the command for performing the recording operation is received, the offset given to the position sensor arithmetic circuit 12 is set to "0". When the reference voltage of the subtraction circuit 64 in FIG. 7 is not at the GND level, the reference voltage may be applied as an offset. The above operation is shown in the flow.

FIG. 20 is a flow chart showing the main processing flow of ON / OFF control of high frequency superposition in the sixth embodiment of the present invention. In the figure, # 51-
# 52 indicates a step.

At step # 51, it is checked whether the CPU 11 has received a command for recording on the optical disc 1 from an initiator (for example, a host computer). When the recording command is received, in the next step # 52,
The offset given to the position sensor arithmetic circuit 12 is set to "0".

As described above, in the invention of claim 6, no offset is given to the output of the position sensor during the recording operation in which the high frequency superimposition is turned off. Therefore, during the reproducing operation, the same effect as that of the optical disk device according to any one of claims 1 to 3 or 5 is obtained, and no abnormal offset is given during the recording operation, so that the incidental information can be detected. is there.

Embodiment of the Invention of Claim 7 As described above, the optical disk device of claim 7 has a lot in common with the optical disk device of claim 6, and the related points have been described. The optical disk device according to claim 7 is the optical disk device according to any one of claims 1 to 3 or 5, characterized in that the offset of the position sensor output is changed when the high frequency superposition is on and when it is off. There is. The hardware configuration, the control of the CPU 11 and the like are the same as those of the optical disk device according to claim 7, and are as described in the embodiment of the invention according to claim 6. Therefore, during the reproducing operation, the claims 1 to 3
Alternatively, an effect similar to that of the optical disk device according to the fifth aspect can be obtained, an accurate offset can be given even during the recording operation, and the incidental information can be accurately detected.

Embodiment 8 of the Invention of Claim 8 In the above-mentioned optical disk device of claims 1 to 7, detection of incidental information during reproduction of the reproduction signal RF and incidental information during recording of the reproduction signal RF are carried out. Although an offset was applied to the position sensor output to detect information, applying the offset during seek, which does not require the detection of incidental information, causes adverse side effects such as instability of the servo system. There are cases. The optical disk device according to claim 8 is characterized in that, in the optical disk device according to claims 1 to 7, the offset is not applied when the incidental information is not detected.

The hardware configuration is the same as that shown in FIGS. 1 and 7, and will be described with reference to FIGS. 1 and 7. In the control of the servo system, applying an offset voltage to the position sensor arithmetic circuit 12 by the offset applying means 13 means shifting the aspherical objective lens (31 in FIG. 3) from the optical axis by the position sensor 51 in FIG. To do. Therefore, it may not be preferable in terms of servo control to perform track crossing with the optical axis misaligned. Therefore, in the optical disk device according to the eighth aspect, the offset voltage is not applied to the position sensor arithmetic circuit 12 by the offset applying means 13 when the track crosses. The operation of the offset applying means 13 is as described above. Next, the above operation will be described with a flow.

FIG. 21 is a flow chart showing the main processing flow when the offset amount is set in the eighth embodiment of the invention. In the figure, # 61 to # 64 indicate steps.

This control is also performed by the CPU 11 shown in FIG. Step # 61 is the flow shown in FIG. 12 described above, and shows the whole in one step. The optical disk device of claim 8 also performs the same operation as that of the optical disk device of claim 3 except when crossing a track (at the time of seek), and therefore has the same flowchart.

Then, in step # 62, it is checked whether or not the seek operation is performed. When seeking (when the optical pickup 3 is moved in the radial direction of the optical disc 1), the process proceeds to step # 63, and the offset given to the position sensor arithmetic circuit 12 is set to "0". When the reference voltage of the subtraction circuit 64 in FIG. 7 is not at the GND level, the reference voltage may be applied as an offset.

At step # 64, it is checked whether the seek operation is completed. When the seek operation is completed,
The flow of FIG. 21 ends. As described above, at the time of seek, the offset given to the position sensor arithmetic circuit 12 is set to "0". Therefore, in the optical disk device of the eighth aspect, the inconvenience that the position detection is impossible in the optical disk devices of the first to seventh aspects is avoided, and the incidental information is detected in a stable state. Moreover, since the servo is also stabilized, it is possible to accurately detect the incidental information.

Embodiment of the Invention of Claim 9 In the optical disk device of claims 1 to 8 described above, there is no limitation on the offset amount given to the position sensor output. However, the output of the position sensor is also limited in the dynamic range due to the power supply voltage of the circuit, etc., and if an excessive offset is applied, there is a problem that the original purpose of the position sensor is not to accurately detect the position of the objective lens. is there. Further, by giving an excessive offset, the optical axis shift of the objective lens becomes too large, which may cause side effects such as instability of the servo.

According to the optical disk device of claim 9, claim 1
The optical disk device according to claim 8 is characterized in that the applied offset amount is limited. Therefore, it is possible to avoid the inconvenience that the position of the objective lens cannot be detected by applying an excessive offset, and the servo is stabilized, so that the incidental information can be accurately detected.

FIG. 22 is a functional block diagram showing the essential structure of an optical disk device according to the ninth aspect of the present invention. The reference numerals in the figure are the same as those in FIG. 1, and 14 indicates a non-volatile memory.

The optical disk device shown in FIG. 9 is different only in that a nonvolatile memory 14 is added to the optical disk device shown in FIG. As already mentioned,
Depending on the offset application amount by the offset application means 13, the aspherical objective lens of the optical pickup 3 (3 in FIG.
The amount of deviation from the optical axis in 1) is determined. However, when the aspherical objective lens is shifted from the optical axis by giving the offset in this way, the following problems occur.

That is, there is a limit to the dynamic range due to the power supply voltage of the subtraction circuit 54 for generating the output of the position sensor 51 shown in FIG. 7, and when an excessive offset is applied, the aspherical objective lens of the optical pickup 3 is applied. The position detection (31 in FIG. 3) cannot be performed accurately. Therefore, in the optical disk device according to the ninth aspect of the present invention, as shown in FIG.
A predetermined value is stored in the non-volatile memory 14 shown in FIG. 2, and the CPU 11 causes the position sensor arithmetic circuit 12 via the offset applying means 13 within the range of the predetermined value.
The offset voltage is applied to.

By thus limiting the amount of offset to be applied, it is possible to avoid the inconvenience that the objective lens becomes unstable due to the application of an excessive offset, and the wobble signal can be accurately detected. More specifically, in the optical disk device according to the ninth aspect, a step jump is performed while the focus servo and the track servo are applied, and the asymmetry detecting means 10 detects the asymmetry.

Then, it is judged that the asymmetry is the minimum, and if it is not the minimum, it is judged whether the offset value to be set is within the range recorded in the nonvolatile memory 14, and then the offset is set. Apply. If the offset value to be applied is outside the range recorded in the nonvolatile memory 14, the maximum (or minimum) value within the range is applied. Next, the above operation will be described with a flow.

FIG. 23 is a flow chart showing the main processing flow when setting the offset amount in the ninth embodiment of the present invention. In the figure, # 71 to # 80 indicate steps.

This control is also performed by the CPU shown in FIG. 1 and FIG.
Performed by 11. Step # 71 corresponds to FIG.
Similar to steps # 1 to # 3, the CPU 11 rotationally drives the spindle motor 2 by a spindle motor driver (not shown), and the semiconductor laser 37 by a driver circuit (not shown) of the semiconductor laser 37.
(Fig. 3) is turned on. Further, a command is given to the servo controller 9, and the focus servo is applied by the focus control means 4.

At step # 72, the CPU 11 commands the servo controller 9 to apply the track servo by the track control means 5. In step # 73, CPU1
1 instructs the servo controller 9 to perform a step jump by the track control means 5. Step # 74
Then, the asymmetry detecting means 10 detects the asymmetry from the track error signal TE.

At step # 75, the CPU 11 checks whether or not the asymmetry is at the minimum value. If the asymmetry is not at the minimum, step #
Proceeding to 76, it is checked whether the offset amount applied by the offset applying means 13 is within the range of the predetermined value stored in the nonvolatile memory 14. If it is within the predetermined value range, in step # 77,
An offset is applied by the offset applying means 13,
The process returns to step # 74 again, and the same processing is repeated.

On the other hand, as a result of checking in step # 76, if the result is not within the range of the predetermined value, the process proceeds to step # 78. In step # 78, the CPU 11
By applying the maximum (or minimum) offset within the range of the predetermined value stored in the nonvolatile memory 14,
The flow of 3 ends. If the result of checking in the previous step # 75 is that the asymmetry is the minimum value, the process proceeds to step # 79.

At step # 79, the CPU 11 gives the offset value at the time when the asymmetry becomes the minimum value to the position sensor arithmetic circuit 12 by the offset applying means 13. Proceeding to step # 80, the CPU 11
The servo controller 9 is instructed to perform the track control means 5
Thus, the step jump is ended, the track servo state is established, and the flow of FIG. 23 is ended. As described above, in the optical disk device of the ninth aspect, the applied offset amount is limited. Therefore, it is possible to avoid the inconvenience that the position of the objective lens cannot be detected by applying an excessive offset, and the servo is stabilized, so that the incidental information can be accurately detected.

Embodiment 10 of the Invention of Claim 10 The value of the asymmetry of the track signal greatly changes due to variations in the optical disc in addition to variations in the optical disc device. In the optical disk device according to the first to ninth aspects, there is a case where the incidental information cannot be accurately detected when the optical disks are exchanged. Claim 1
The optical disk device of No. 0 is characterized in that the offset amount given to the output of the position sensor is readjusted when the power is turned on or the optical disk is inserted in the optical disk device of the first to ninth aspects.

FIG. 24 is a diagram showing a main part configuration of an optical disc insertion detector in an optical disc device according to a tenth aspect of the present invention, wherein (1) is a functional block diagram and (2) is a structural diagram. Reference numerals in the figure are the same as those in FIG.
Is a media-in switch, and 83 is a drive housing.

As shown in FIGS. 24 (1) and 24 (2), a media-in switch 82 is provided which is pushed by the optical disc 1 and is turned on when the optical disc 1 is inserted into the drive housing 83. This media-in switch 82
When is turned on, the signal line 81 changes to L level, for example.

When the CPU 11 detects this state, it is determined that the optical disk has been inserted. Then, at this point, the offset amount applied by the offset applying means 13 is adjusted. It should be noted that the adjustment can be made at the same time when the CPU 11 is reset when the power is turned on. Next, the above operation will be described with a flow.

FIG. 25 is a flow chart showing the main processing flow at the time of setting the offset amount in the tenth embodiment of the present invention. In the figure, # 81 to # 82
Indicates a step.

In step # 81, it is checked whether or not an optical disk has been inserted (it is also possible to check whether or not the power is turned on). When it is detected that the optical disc is inserted, the offset amount is readjusted in step # 82. Therefore, the incidental information can be accurately detected regardless of variations in the optical disc.

Embodiment 11 of the Invention of Claim 11 In the optical disk device of claim 1 to claim 10,
If the warp of the disk changes due to a temperature change or the asymmetry changes due to the temperature characteristic of the optical system, the incidental information cannot be accurately detected. The optical disk device according to claim 11 is characterized in that, in the optical disk device according to claim 1 to claim 10, the offset amount given to the output of the position sensor is readjusted due to a temperature change.

FIG. 26 is a functional block diagram showing a main structure of a temperature detecting section in the optical disk device according to the tenth aspect of the present invention. Reference numerals in the figure are the same as those in FIG. 1, 91 is a temperature sensor, 92 is a resistor, 93 is a buffer amplifier, 94 is an A / D conversion circuit, and X is a point on the signal line.

The temperature sensor 91 is a sensor for detecting the temperature of the optical disk device (drive), and is a thermistor whose resistance value changes according to the temperature. For example,
The thermistor is an element whose resistance value decreases as the temperature rises and conversely increases as the temperature falls.

In FIG. 26, the temperature sensor 91 is connected in series with the resistor 92 and is lowered to the GND level. By connecting in this way, the voltage at the point X on the signal line fluctuates due to temperature changes. The voltage at the point X is buffered by the buffer amplifier 93 in the next stage and output to the A / D conversion circuit 94 in the next stage. In addition,
The buffer amplifier 93 is inserted to reduce the error in the detected temperature due to the input current required by the A / D conversion circuit 94.

The A / D conversion circuit 94 converts the detected analog voltage value into a digital value and outputs it to the CPU 11. When the CPU 11 detects a temperature change based on the output from the temperature detector of FIG. 26, the CPU 11 adjusts the offset amount applied by the offset applying unit 13 at that time. The above operation will be described with a flow.

FIG. 27 is a flow chart showing the flow of main processing when setting the offset amount in the eleventh embodiment of the present invention. In the figure, # 91 to # 93
Indicates a step.

In step # 91, the CPU 11 detects the temperature inside the drive by the output of the A / D conversion circuit 94. In step # 92, the CPU 11 again detects the temperature by the output of the A / D conversion circuit 94, and checks whether the difference from the temperature at the previous detection is a predetermined value or more.

If the difference from the temperature at the previous detection is a predetermined value or more, the process proceeds to step # 93, and the offset amount applied by the offset applying means 13 is adjusted. Therefore, the influence of the temperature change is removed, and the incidental information can be accurately detected.

Embodiment 12 of the Invention of Claim 12 In the optical disk device of claim 11, the offset amount is readjusted in response to a change in asymmetry due to temperature change or the like, but the passage of time is not taken into consideration. The invention of claim 12 is also premised on the inventions of claims 1 to 10, and is more accurate by readjusting the offset amount due to aging as well as the temperature change similar to the optical disk device of claim 11. The feature is that the asymmetry of the track signal can be removed.

FIG. 28 is a functional block diagram showing the structure of the main part of the timer unit of the optical disk device of the twelfth aspect of the invention. Reference numerals in the figure are the same as those in FIG. 1, and 101 indicates a timer circuit.

FIG. 28 shows a circuit in which the timer circuit 101 outputs a time signal to the CPU 11 at regular time intervals. As the timer circuit 101,
A counter composed of a flip-flop and an oscillator may be used, or a timer LSI may be of a type that outputs a signal at regular intervals. Upon receiving the signal from the timer circuit 101, the CPU 11 adjusts the offset amount applied by the offset applying means 13 by the arbitrary method described above. The above operation will be described with a flow.

FIG. 29 is a flow chart showing the main processing flow when setting the offset amount in the twelfth embodiment of the present invention. In the figure, # 101 to # 1
02 indicates a step.

At step # 101, the CPU 11 checks the presence / absence of a signal from the timer circuit 101. When the signal from the timer circuit 101 is received, step # 102
Then readjust the offset amount.

As described above, in the disk device of the twelfth aspect, in the optical disk device of the first to tenth aspects, the offset amount given to the position sensor output is readjusted with time. Therefore, the influence of the change in asymmetry due to the passage of time is removed, and accurate incidental information can be detected. In addition, if the readjustment interval is sufficiently short, the effect of temperature change is also removed.

Embodiment 13 of the Invention of Claim 13 The invention of claim 13 is also based on the invention of claims 1 to 10, and is characterized by the timing of readjustment of the offset amount given to the position sensor output. ing. As described above, in the thirteenth embodiment of the present invention, the offset amount given to the output of the position sensor is readjusted immediately before the data recording or reproducing operation, so that the incidental information can always be accurately detected. become.

FIG. 30 is a functional block diagram showing an embodiment of the system configuration to which the optical disk device of the present invention is connected. Reference numerals in the figure are the same as those in FIG. 1, 111 is an initiator, 112 is a SCSI interface device, and 113 is a SCSI (Small Computer System Interface) controller.

In FIG. 30, the initiator 111
Is a device that issues a command to an optical disk device (not shown), for example, a host computer. The initiator 111 issues a command for recording or reproducing data to the SCSI controller 113 via the SCSI interface device 112, and the SCSI controller 1
13 informs the CPU 11 of the contents of the command. CP
If the received command is a command for recording / reproducing information on the optical disc, the U 114 readjusts the offset amount of the offset applying unit 13 by the method described above. The above operation is shown by a flow.

FIG. 31 is a flow chart showing the main processing flow when setting the offset amount in the thirteenth embodiment of the present invention. In the figure, # 111 and # 1
12 shows a step.

This control is also performed by the CPU 11. In step # 111, the CPU 11 monitors whether or not the command for recording or reproducing on the optical disc 1 is received from the initiator 121. When the command is received, the offset amount is readjusted in the next step # 112, and the flow of FIG. 31 is ended.

As described above, in the disk device of claim 13, in the optical disk device of claims 1 to 10, the offset amount given to the position sensor output is readjusted immediately before the data recording or reproducing operation. There is.
Therefore, it is always possible to accurately detect the incidental information.

[0163]

According to the optical disk device of the present invention, an offset is given to the output of the position sensor of the objective lens to change the relative positional relationship between the objective lens and the optical axis. The asymmetry of a certain track signal is removed. Therefore,
It becomes possible to detect the incidental information accurately with an inexpensive configuration that does not require the addition of a special circuit.

According to the optical disk device of claim 2,
In the optical disc apparatus, the track signal is detected while the focus servo is applied, and the relative positional relationship between the objective lens and the optical axis is changed to minimize the asymmetry of the track signal. Therefore, it is possible to more accurately remove the asymmetry of the track signal as compared with the optical disk device according to the first aspect, and it is possible to more accurately detect the incidental information.

According to the optical disk device of claim 3,
In the optical disc device of,
In that state, the track signal is measured to minimize the asymmetry. Therefore, the asymmetry of the track signal can be removed without being affected by the focus fluctuation, and the incidental information can be detected more accurately.

According to the optical disk device of claim 4,
In the optical disc device, the RF signal mixing amount detecting means is provided, and the relative positional relationship between the objective lens and the optical axis is changed so that the mixing amount of the RF signal into the track signal is minimized. Therefore, it is possible to detect the incidental information more accurately as compared with the optical disc device according to the first aspect.

According to the optical disk device of claim 5, claim 1
Therefore, in the optical disk device according to the fourth aspect, the offset application amount given to the output of the position sensor is changed depending on the radial position of the optical disk. Therefore, the influence of the warp of the optical disc is removed, and the incidental information can be accurately detected.

According to the optical disk device of claim 6, claim 1
Therefore, in the optical disk device according to the third or fifth aspect, the offset is applied during the reproducing operation, and the offset is not applied during the recording operation. As described above, since the position sensor output is not offset during the recording operation in which the high frequency superposition is turned off, the same effect as that of the optical disk device according to claim 1 to claim 3 or claim 5 is obtained during the reproducing operation. Since the abnormal offset is not given during the recording operation, the incidental information can be detected.

According to the optical disk device of claim 7, claim 1
Therefore, in the optical disk device according to claim 3 or 5, the offset of the position sensor output is changed when the high frequency superposition is on and when it is off. Therefore, during the reproducing operation, the same effects as those of the optical disk device according to the first to third or fifth aspects can be obtained, and during the recording operation, it becomes possible to give an accurate offset and to detect the incidental information. Can be done accurately.

According to the optical disk device of claim 8, claim 1
Therefore, in the optical disk device according to the seventh aspect, the offset is not applied when the incidental information is not detected. Therefore, the servo does not become unstable unnecessarily, and the incidental information is detected in a stable state, so that the incidental information can be accurately detected.

According to the optical disk device of claim 9, claim 1
Therefore, in the optical disk device according to the eighth aspect, the applied offset amount is limited. Therefore, it is possible to avoid the inconvenience that the position of the objective lens cannot be detected by applying an excessive offset, and the servo is stabilized, so that the incidental information can be accurately detected.

According to a tenth aspect of the optical disc apparatus of the first to ninth aspects, the offset amount given to the output of the position sensor is readjusted when the power is turned on or when the optical disc is inserted. Therefore,
The incidental information can be accurately detected regardless of variations in the optical disc.

According to the optical disk device of the eleventh aspect, in the optical disk device of the first to tenth aspects, the offset amount given to the position sensor output is readjusted due to the temperature change. Therefore, the influence of the temperature change is removed, and the incidental information can be accurately detected.

According to the disk device of claim 12, claim 1
Therefore, in the optical disk device according to the tenth aspect, the offset amount given to the position sensor output is readjusted with time. Therefore, the influence of the change in asymmetry due to the passage of time is removed, and accurate incidental information can be detected. In addition, if the readjustment interval is sufficiently short, the effect of temperature change can be eliminated.

According to the disk device of claim 13, claim 1
Therefore, in the optical disk device of the tenth aspect, the offset amount given to the output of the position sensor is readjusted immediately before the data recording or reproducing operation. Therefore, it is always possible to accurately detect the incidental information.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an embodiment of the main configuration of an optical disk device of the present invention.

2 is a circuit diagram showing an example of a detailed configuration of a preamplifier section 7 and its peripheral circuits in FIG.

FIG. 3 is an exploded perspective view showing a main structure of an optical system provided inside the optical pickup 3.

FIG. 4 is a diagram showing a main configuration of an optical system of the optical pickup 3 shown in FIG.

FIG. 5 is a diagram showing a main part configuration of an aspherical objective lens 31.

6 is a diagram illustrating a positional relationship between a slit 44 shown in FIG. 5 and a lens position sensor.

7 is a functional block diagram showing a configuration example of a position sensor arithmetic circuit 12 shown in FIG.

FIG. 8 is a timing chart showing an example of a variation state of the track error signal TE.

FIG. 9 is a diagram showing the relationship between the intensity distribution of the amount of light incident on the light receiving surfaces of the four-division light receiving elements 21A to 21D and the asymmetry.

FIG. 10 is a flowchart showing a main processing flow when setting an offset amount in the optical disc device of the present invention.

FIG. 11 is a timing chart showing an example of a variation state of the track error signal TE at the moment of performing a step jump.

FIG. 12 is an optical disk device according to a third aspect of the invention,
It is a flow chart which shows the flow of the main processing at the time of offset amount setting.

FIG. 13 is a diagram of a waveform example for explaining a state in which the reproduction signal RF is mixed in the wobble signal.

FIG. 14 is an optical disk device according to a fourth aspect of the invention,
It is a functional block diagram which shows one Example of the circuit which takes out the reproduction | regeneration signal RF mixed with the wobble signal.

FIG. 15 is a flowchart showing a main processing flow when setting an offset amount in the fourth embodiment of the present invention.

FIG. 16 is a side view showing an example of a state in which a warped optical disk is set in the apparatus.

FIG. 17 is a flowchart showing a main processing flow when setting an offset amount in the fifth embodiment of the invention.

FIG. 18 is a diagram showing a track error signal TE when focus servo is applied and track servo is not applied.

FIG. 19 is an optical disk device according to a sixth aspect of the invention,
FIG. 3 is a functional block diagram showing an embodiment of a wobble signal detection circuit at the time of recording on the optical disc 1.

FIG. 20 is a flowchart showing a main processing flow of on / off control of high frequency superposition in the sixth embodiment of the invention.

FIG. 21 is a flowchart showing a flow of main processing when setting an offset amount in the eighth embodiment of the present invention.

FIG. 22 shows an optical disk device according to a ninth aspect of the present invention.
It is a functional block diagram showing the composition of the important section.

FIG. 23 is a flowchart showing a main processing flow when setting an offset amount in the ninth embodiment of the present invention.

FIG. 24 is a diagram showing a main configuration of an optical disc insertion detection section in an optical disc device according to a tenth aspect of the present invention.

FIG. 25 is a flowchart showing a main processing flow when setting an offset amount in the tenth embodiment of the invention.

FIG. 26 is a functional block diagram showing a main configuration of a temperature detection unit in the optical disk device of the invention of claim 10;

FIG. 27 is a flowchart showing a flow of main processing when setting an offset amount in the eleventh embodiment of the present invention.

FIG. 28 is a functional block diagram showing a main configuration of a timer section of an optical disk device according to a twelfth aspect of the invention.

FIG. 29 is a flowchart showing a main processing flow when setting an offset amount in the twelfth embodiment of the present invention.

FIG. 30 is a functional block diagram showing an embodiment of a system configuration to which the optical disk device of the present invention is connected.

FIG. 31 is a flowchart showing a main process flow when setting an offset amount in the thirteenth embodiment of the present invention.

[Explanation of symbols]

 1 Optical Disk 2 Spindle Motor 3 Optical Pickup 4 Focus Control Means 4a Focus Signal Calculation Circuit 5 Track Control Means 5a Track Signal Calculation Circuit 6 Carriage Servo Means 7 Preamplifier Section 8 Adder Circuit 9 Servo Controller 10 Asymmetry Detection Means 11 CPU 12 Position Sensor Calculation Circuits 13 Offset applying means

Claims (13)

[Claims] 1. An optical disc comprising: a focus control unit for focusing a light beam from a semiconductor laser on an optical disc by an objective lens; a track control unit; and a carriage servo unit for moving the objective lens in a radial direction of the optical disc. In an optical disc device that detects the reproduction signal on the track by detecting the incidental information of the optical disc on which track wobble recording is performed by causing the light flux to follow the upper track, the deviation of the condensed light flux from the track center is detected. A plurality of track light-receiving elements, an I / V conversion circuit that converts the output from the track light-receiving element into a current / voltage, and a track signal calculation circuit that generates a track signal based on the difference between the outputs from the I / V conversion circuit. , Detection of deviation from the neutral point of the objective lens in the direction orthogonal to the track A position sensor, a position sensor arithmetic circuit that calculates an output from the position sensor, and an offset applying unit that gives an offset to the output of the position sensor, according to a track signal that is an output of the track signal arithmetic circuit. The wobble signal is detected from the output of the track signal arithmetic circuit by changing the asymmetry of the track signal by changing the offset amount given from the offset applying means. 2. The optical disk device according to claim 1, wherein the offset application amount given to the output of the position sensor is determined so that asymmetry of a track signal in a state where focus servo is applied is minimized. Optical disk device. 3. The optical disk device according to claim 1, further comprising step jump executing means, wherein an offset application amount given to the output of the position sensor is step jump from a track-on state,
An optical disk device, characterized in that the asymmetry of a track signal during a step jump is determined to be a minimum. 4. The optical disk device according to claim 1, further comprising a reproduction signal mixture amount detection means for detecting a mixture amount of the reproduction signal into a track signal, wherein an offset application amount given to an output of the position sensor is track-on. An optical disk device, characterized in that the reproduction signal is determined so as to be minimally mixed with the track signal in the state. 5. The optical disk device according to any one of claims 1 to 4, wherein the offset application amount given to the output of the position sensor is changed depending on the radial position of the optical disk. 6. The optical disk device according to claim 1, wherein an offset is applied during the reproducing operation and no offset is applied during the recording operation. 7. The optical disk device according to claim 1, wherein the offset during the reproducing operation is determined by the output of the track signal operation circuit when the high frequency superposition is on, and the offset during the recording operation is the high frequency superposition. An optical disk device characterized by being determined by the output of a track signal calculation circuit when it is off. 8. The optical disk device according to claim 1, wherein an offset is not applied when the incidental information is not detected. 9. The optical disk device according to claim 1, wherein the applied offset amount is limited. 10. The optical disk device according to claim 1, wherein an applied offset amount is adjusted when the power is turned on or when the optical disk is inserted. 11. The optical disk device according to any one of claims 1 to 10, further comprising: a temperature detecting means, and readjusting an offset amount applied according to a temperature change. 12. The optical disk device according to claim 1, wherein the applied offset amount is readjusted at predetermined time intervals. 13. The optical disk device according to claim 1, wherein the offset amount to be applied is readjusted immediately before a data recording or reproducing operation.