JP2004095044A - Tilt control method for optical disk recording/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tilt control method for an optical disk recording/reproducing device, which carries out a signal recording/reproducing operation on a disk by an optical pickup. <P>SOLUTION: This optical disk recording/reproducing device uses an optical pickup 2 equipped with a tilt adjustment coil 6 for adjusting the tilting of an objective lens. A DC voltage value is obtained from a driving signal supplied to a focusing coil 4 incorporated in the optical pickup 2 at an inner peripheral and an outer peripheral positions of the disk, a relation between the position and the DC voltage value is calculated from the obtained DC voltage value, and a signal obtained by adding the DC voltage value calculated on the basis of the relation to an AC signal contained in the driving signal supplied to the focusing coil 4 is supplied to the tilt adjustment coil 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk recording / reproducing apparatus configured to record a signal on a disk by a laser radiated from an optical pickup and to perform an operation of reproducing a signal recorded on the disk by the laser.
[0002]
[Prior art]
2. Description of the Related Art Disk players that read signals recorded on a disk using an optical pickup have become widespread, but recently, in addition to a reproducing function, a signal is recorded on the disk by a laser emitted from the optical pickup. An optical disk recording / reproducing device configured to perform such operations has been commercialized. Recently, it has become possible to record a signal while controlling the rotation of the disk at a constant high linear velocity of 4 times, 8 times, 12 times, 16 times, etc. with respect to a specified recording linear velocity. An optical disk recording / reproducing apparatus having the configuration has been developed.
[0003]
In an optical disk recording / reproducing apparatus configured to be able to perform a recording / reproducing operation by rotating a disk at a high speed, it is necessary to accurately irradiate a signal track on a disk surface with laser light emitted from an optical pickup. It is required that the focus control operation and the tracking control operation be performed accurately. Such a focus control operation is performed by supplying a drive current to a focusing coil that displaces the objective lens in the disk surface direction, and a tracking control operation is performed by supplying a drive current to a tracking coil that displaces the objective lens in the disk radial direction. It is done by doing.
[0004]
[Problems to be solved by the invention]
Recently, the density of signals has been increased in order to record many signals on a disk. In order to increase the density, it is necessary to irradiate the disk surface with laser light in an optimal state. In order to perform such an operation, an optical pickup configured to perform an operation of correcting a relative angle shift between a disk and an objective lens, that is, a tilt adjustment operation, has been developed.
[0005]
An object of the present invention is to provide a tilt control method suitable for an optical disk recording / reproducing apparatus using an optical pickup capable of performing such a tilt adjustment operation.
[0006]
[Action]
The present invention relates to an optical disk recording / reproducing apparatus using an optical pickup having a tilt adjusting coil for adjusting the tilt of an objective lens, wherein a DC voltage value is obtained from a driving signal supplied to a focusing coil incorporated in the optical pickup. At the inner and outer peripheral positions of the disk, determine the relationship between the position and the DC voltage value from the determined DC voltage value, and supply the DC voltage value calculated based on the relationship to the focusing coil. A signal obtained by adding the AC signal included in the drive signal to the tilt adjustment coil is supplied to the tilt adjustment coil.
[0007]
【Example】
FIG. 1 is a block diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention, and FIG.
[0008]
In FIG. 1, reference numeral 1 denotes a disk mounted on a turntable (not shown) driven to rotate by a spindle motor (not shown), and is configured to be driven to rotate by rotation of the turntable. . Also. Position information data is recorded on the disc 1 by a groove called a wobble, and a signal recording / reproducing operation is performed based on a wobble signal obtained from the groove. 2 is a photodetector 3 which incorporates a laser diode for irradiating the disk 1 with a light beam and a monitoring diode for monitoring light emitted from the laser diode, and receives a light beam reflected from the signal surface of the disk 1. Is an optical pickup in which the disc 1 is moved in the radial direction of the disc 1 by a pickup feed motor (not shown).
[0009]
The optical pickup 2 includes a focusing coil 4 for displacing an objective lens (not shown) in the disk surface direction, a tracking coil 5 for displacing the objective lens in a radial direction of the disk 1, and an angle of the objective lens with respect to the disk 1. The tilt adjusting coil 6 for adjusting the tilt angle is incorporated.
[0010]
Reference numeral 7 denotes a focusing control operation for focusing a light beam of the optical pickup 2 on a signal surface of the disk 1 based on a signal obtained from a photodetector 3 incorporated in the optical pickup 2, and The pickup control circuit performs a tracking control operation for following a signal track on a signal surface, and is configured to output a tracking control signal based on a tracking error signal and a focusing control signal based on a focus error signal.
[0011]
Reference numeral 8 denotes a tracking coil drive circuit to which a tracking control signal output from the pickup control circuit 7 is input, and is configured to supply a drive signal to the tracking coil 5 incorporated in the optical pickup 2. . Reference numeral 9 denotes a focusing coil drive circuit to which a focusing control signal output from the pickup control circuit 7 is input, which is configured to supply a drive signal to the focusing coil 5 incorporated in the optical pickup 2. .
[0012]
FIG. 2 shows the relationship between the drive signal supplied to the focusing coil 5 at the position on the inner circumference and the position on the outer circumference of the disk 1 when the disk 1 is inclined as shown. AC signals are superimposed on A and B. The DC voltages A and B act to displace the position of the objective lens in accordance with the positional relationship between the signal surface of the disk 1 and the optical pickup 2, and differ depending on the inclination of the disk 1. become. The AC signal superimposed on the DC voltage acts to finely displace the objective lens in the direction perpendicular to the signal surface of the disk 1 in accordance with the deviation of the signal surface of the disk 1. .
[0013]
Reference numeral 10 denotes a position detection circuit for detecting the position of the optical pickup 2 based on the position information data reproduced from the disk 1. Reference numeral 11 detects a DC voltage from the drive signal output from the focusing coil drive circuit 9, and A tilt control circuit 12 for performing a tilt control operation is a memory circuit whose operation is controlled by the tilt control circuit 11.
[0014]
In such a configuration, the DC voltage A at the inner peripheral position and the DC voltage B at the outer peripheral position of the disk 1 are obtained by moving the optical pickup 2 to each position, and the values are stored in the memory circuit 12 and the values are stored in the memory circuit 12. 1 to determine the relationship between the position and the DC voltage from the position above. The tilt control circuit 11 is configured to output a DC voltage calculated based on a relationship between a DC voltage and a position derived from the DC voltage values A and B stored in the memory circuit 12. ing.
[0015]
Reference numeral 13 denotes an amplifier circuit for amplifying the signal output from the tilt control circuit 11, reference numeral 14 denotes a capacitor for cutting a DC signal from the drive signals output from the focusing coil drive circuit 9, and reference numeral 15 denotes a signal passing through the capacitor. An amplifying circuit that receives an AC signal and amplifies the signal. An adder circuit 16 adds the DC signal amplified by the amplifier circuit 13 and the AC signal amplified by the amplifier circuit 15. Reference numeral 17 denotes a tilt coil driving circuit to which the signal added by the adding circuit 16 is input, and is connected so as to supply a driving signal to the tilt adjusting coil 6 incorporated in the optical pickup 2.
[0016]
The optical disk recording / reproducing apparatus according to the present invention is configured as described above, and the operation will be described next.
[0017]
The tilt adjustment operation is started by performing a focusing control operation in a state where the optical pickup 2 is located at a predetermined position on the inner peripheral side of the disk 1, for example, a lead-in area. When such an operation is performed, a focusing control signal is output from the pickup control circuit 7 to the focusing coil drive circuit 9 based on a signal obtained from the photodetector 3 incorporated in the optical pickup 2.
[0018]
As a result, a driving signal shown in FIG. 2, that is, a signal in which an AC signal is superimposed on a DC voltage A is supplied to the focusing coil 4 from the focusing coil driving circuit 9. The objective lens is displaced to an optimum position for performing a focusing operation on the disk 1 by the DC voltage A, and a light beam is focused on a signal surface of the disk 1 which fluctuates with rotation of the disk 1 by an AC signal. A displacement operation is performed to cause the displacement.
[0019]
As described above, the focusing control operation at the predetermined position on the inner peripheral side of the disk 1 is performed. In this state, the drive signal supplied from the focusing coil drive circuit 9 to the focusing coil 4 is transmitted to the tilt control circuit 11. It has been entered. Then, the tilt control circuit 11 detects the value of the DC voltage A from the input drive signal, and stores the value in the memory circuit 12.
[0020]
When such an operation is performed, an operation of moving the optical pickup 2 to a predetermined position on the outer peripheral side of the disk 1, for example, a lead-out position, is performed. The moving operation is recorded on the disk 1. This can be performed by detecting the position information data by the position detection circuit 10. When the optical pickup 2 is moved to a predetermined position on the outer peripheral side, the focusing control operation is performed as described above. When such a focusing control operation is performed, a focusing control signal is output from the pickup control circuit 7 to the focusing coil drive circuit 9 based on a signal obtained from the photodetector 3 incorporated in the optical pickup 2.
[0021]
As a result, the driving signal shown in FIG. 2, that is, a signal in which the AC signal is superimposed on the DC voltage B is supplied to the focusing coil 4 from the focusing coil driving circuit 9. The objective lens is displaced to an optimal position for performing a focusing operation on the disk 1 by the DC voltage B, and a light beam is focused on a signal surface of the disk 1 which fluctuates with rotation of the disk 1 by an AC signal. A displacement operation is performed to cause the displacement.
[0022]
As described above, the focusing control operation is performed at a predetermined position on the outer peripheral side of the disc 1. In this state, the drive signal supplied from the focusing coil drive circuit 9 to the focusing coil 4 is input to the tilt control circuit 11. It has been done. Then, the tilt control circuit 11 detects the value of the DC voltage B from the input drive signal, and stores the value in the memory circuit 12.
[0023]
When the detection operation of the DC voltage value A at the inner peripheral position and the DC voltage value B at the outer peripheral position and the storage operation in the memory circuit 12 are performed, the difference between the DC voltage values A and B and the inner peripheral position and the outer peripheral position are determined. The relationship between the DC voltage value and the position on the disk 1 can be obtained from the relationship. Therefore, the DC voltage value corresponding to each position on the disk 1 is calculated, and the tilt control circuit 11 can output a signal of the calculated DC voltage value.
[0024]
The DC signal output from the tilt control circuit 11 is input to the amplification circuit 13, amplified, and then input to the addition circuit 16. On the other hand, the drive signal output from the focusing coil drive circuit 9 is input to an amplifier circuit 15 via a capacitor 14. The signal input to the amplifier circuit 15 is an AC signal obtained by cutting a DC signal, Is a signal for displacing the objective lens with respect to the surface shake. The AC signal amplified by the amplifier circuit 15 is input to the adder circuit 16 and added to the DC signal amplified by the amplifier circuit 13 and then input to the tilt coil drive circuit 17.
[0025]
As a result, a signal in which an AC signal is superimposed on a DC signal corresponding to a position on the disk 1 is supplied from the tilt coil driving circuit 17 to the tilt adjusting coil 6 incorporated in the optical pickup 2. Therefore, the tilt of the objective lens is adjusted by the tilt adjusting coil 6, and the optical pickup 2 can be controlled to be in an optimal state with respect to the signal surface of the disk 1.
[0026]
In the present embodiment, the position detection operation by the position detection circuit 10 is performed using the position information data recorded on the disk 1. However, the position detection operation is performed by using the rotation speed of the electric motor that moves the optical pickup 2. You can also do it. Further, the DC voltage of the drive signal supplied to the focusing coil 4 is detected at the inner peripheral position and the outer peripheral position, and the inner peripheral position is set to the innermost peripheral position of the disk 1 and the outer peripheral position is set. At the outermost position, the change in the value of the DC voltage representing the inclination of the disk 1 with respect to the optical pickup 2 becomes large, so that the relationship between the position and the DC voltage can be easily derived.
[0027]
【The invention's effect】
The present invention relates to an optical disk recording / reproducing apparatus using an optical pickup having a tilt adjusting coil for adjusting the tilt of an objective lens, wherein a DC voltage value is obtained from a driving signal supplied to a focusing coil incorporated in the optical pickup. At the inner and outer peripheral positions of the disk, determine the relationship between the position and the DC voltage value from the determined DC voltage value, and supply the DC voltage value calculated based on the relationship to the focusing coil. Since the signal obtained by adding the AC signal included in the drive signal to the tilt adjusting coil is supplied to the tilt adjusting coil, the optimum tilt adjusting operation can be performed at each position on the disk.
[0028]
Further, according to the present invention, the inner and outer peripheral positions are determined from the position information data recorded on the disc, so that the operation of setting the position to be detected can be performed accurately, and as a result, the tilt control can be performed. The relationship between the position and the DC voltage can be accurately obtained.
[0029]
In the present invention, since the inner peripheral position is the innermost peripheral position of the disk and the outer peripheral position is the outermost peripheral position of the disk, the change in the value of the DC voltage representing the inclination of the disk with respect to the optical pickup becomes large, and The relationship with the DC voltage can be easily derived.
[0030]
Further, the present invention has an advantage that the configuration is simplified because the inner peripheral position and the outer peripheral position are determined based on the number of rotations of the electric motor for moving the optical pickup.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing an embodiment of an optical disk recording / reproducing apparatus according to the present invention.
FIG. 2 is a diagram for explaining the operation of the present invention.
[Explanation of symbols]
Reference Signs List 1 disc 2 optical pickup 4 focusing coil 5 tracking coil 6 tilt adjusting coil 7 pickup control circuit 9 focusing coil drive circuit 10 position detection circuit 11 tilt control circuit 12 memory circuit 16 addition circuit 17 tilt coil drive circuit

Claims (4)

In an optical disc recording / reproducing apparatus using an optical pickup provided with a tilt adjusting coil for adjusting the tilt of an objective lens, a DC voltage value is obtained from a drive signal supplied to a focusing coil incorporated in the optical pickup. The relationship between the position and the DC voltage value is obtained from the obtained DC voltage value at the circumferential position and the outer circumferential position, and the DC voltage value calculated based on the relationship and the drive signal supplied to the focusing coil are calculated. A tilt control method for an optical disk recording / reproducing apparatus, wherein a signal obtained by adding an included AC signal is supplied to a tilt adjusting coil. 2. The tilt control method according to claim 1, wherein the inner peripheral position and the outer peripheral position are determined from position information data recorded on the disk. 3. The tilt control method according to claim 2, wherein the inner peripheral position is the innermost peripheral position of the disk, and the outer peripheral position is the outermost peripheral position of the disk. 2. The tilt control method according to claim 1, wherein the inner peripheral position and the outer peripheral position are determined based on the number of revolutions of a motor for moving the optical pickup.

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