JP2006048824A - Lens tilt learning control method and optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens tilt learning control method capable of performing lens tilt learning control within a short time, and an optical disk device capable of shortening start time by using the method. <P>SOLUTION: The lens tilt learning control method for performing learning control to maintain the proper state of a relative angle between an objective lens and an optical disk when a laser beam converged from the objective lens is applied to the optical disk to record/reproduce information includes dividing an optical disk area for executing tilt learning into a plurality in the diameter direction of the optical disk, executing tilt learning only in the innermost peripheral area of the divided optical disk areas at the starting time, determining the execution of tilt learning at a seeking destination when seeking occurs, and executing tilt learning in an area including the position before seeking to the position when tilt learning is not executed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides learning control so that the relative angle between the objective lens and the optical disc is maintained in an appropriate state in order to maintain the recording / reproducing characteristics even when the optical disc is inclined with respect to the objective lens. The present invention relates to a lens tilt learning control method and an optical disc apparatus having the lens tilt learning control function.

  As optical disc devices, audio CDs, CD-ROMs, CD-R / RWs, DVDs, and the like have already been put into practical use, and application to various fields and development for high performance are being actively conducted. . Particularly recently, with the rapid market expansion of personal computers, the penetration rate of built-in optical disk devices in personal computers has increased.

  Information is recorded on or reproduced from the optical disc by irradiating the optical disc with laser light condensed by an objective lens. In order to perform accurate recording / reproduction, it is necessary that the distance between the objective lens and the optical disk is properly maintained, which is performed by acquiring a focus error signal.

  In a recordable DVD drive device, the relative angle between the objective lens and the optical disk is maintained in an appropriate state in order to maintain the recording / reproducing characteristics even when the optical disk is inclined with respect to the objective lens. In this way, lens tilt learning control is performed.

  The conventional lens tilt learning control measures the tilt at a plurality of points while moving the optical pickup with respect to the entire surface of the optical disc, and obtains an approximate curve of tilt over the entire surface of the optical disc, and its approximate curve. Based on the above, a tilt control technique for applying a tilt drive value corresponding to the position to the tilt actuator when seeking to a position in an arbitrary radial direction of the optical disk has been used.

As an example of a conventional lens tilt learning control method, a technique for performing tilt learning over the entire surface of an optical disk is described in (Patent Document 1).
JP 2003-281761 A

  However, according to the conventional method, tilt measurement must be performed over the entire surface of the optical disk at the time of startup, and the time required for startup becomes longer. Further, since the state of warping of the optical disk changes as the temperature changes, the learned tilt curve shifts and it is necessary to learn over the entire surface of the optical disk again.

  The present invention has been made to solve the above-described problems, and a lens tilt learning control method capable of performing lens tilt learning control in a short time, and shortening a startup time using the lens tilt learning control method. An object of the present invention is to provide an optical disc apparatus capable of performing the above.

The present invention has been made in order to solve the above-described problem. When information is recorded / reproduced by irradiating the optical disk with laser light condensed by the objective lens, the objective lens is placed between the optical disk and the optical disk. In the lens tilt learning control method for performing learning control so as to maintain the relative angle of the optical disk in an appropriate state, the optical disk area to be subjected to tilt learning is divided into a plurality of radial directions of the optical disk, and the innermost of the divided optical disk areas is Tilt learning is performed only in the circumferential region, and when seek occurs, it is determined whether or not tilt learning is performed at the seek destination, and if tilt learning is not performed, before seeking to that position The lens tilt learning control method is characterized in that tilt learning is performed in a region including the position.

  According to the present invention, the lens tilt learning control can be performed in a short time, and the activation time can be shortened. In addition, even if the optical disk warpage changes due to a change in temperature, when a seek occurs, tilt learning is performed at a predetermined temperature in the vicinity of the seek destination. Can be performed.

  According to the first aspect of the present invention, when the optical disk is irradiated with the laser light condensed by the objective lens and information is recorded and reproduced, the relative angle between the objective lens and the optical disk is in an appropriate state. In the lens tilt learning control method for performing learning control so as to maintain the same, the optical disk area for which the tilt learning is performed is divided into a plurality of areas in the radial direction of the optical disk, and the tilt learning is performed only in the inner peripheral area of the divided optical disk area at the time of startup. When the seek occurs, it is determined whether or not the tilt learning is performed at the seek destination.If the tilt learning is not performed, the area including the position is searched before seeking to the position. A lens tilt learning control method characterized by performing tilt learning.

  When starting up, tilt learning is performed only in the area on the inner circumference side of the optical disk area, and tilt learning in other areas is performed based on a predetermined determination every time a seek occurs, thereby shortening the time required for starting up. It is possible to improve the efficiency of tilt learning and shorten the time. In addition, even if the optical disk warpage changes due to a change in temperature, when a seek occurs, tilt learning is performed at a predetermined temperature in the vicinity of the seek destination. Can be performed.

  According to the second aspect of the present invention, the tilt actuator in which the objective lens is movable in the tilt direction with respect to the radial direction of the optical disc, the tilt driving means for driving the tilt actuator, and the recording with respect to the tilt of the disc with respect to the objective lens are recorded. / Tilt learning means for learning the tilt amount or tilt drive voltage of the objective lens with the optimum reproduction characteristics, and tilt curve calculation for calculating the tilt curve over the entire surface of the optical disk based on the learned tilt amount or tilt drive voltage In an optical disc apparatus comprising: means and a tilt control means for applying a tilt drive voltage at a corresponding disc radial position to the tilt drive means when seeking to an arbitrary optical disc radial position based on a tilt curve. Is divided into multiple parts in the radial direction of the optical disc, An optical disk apparatus characterized by comprising a means for tilt learning and tilt curve calculation only in the region.

  Since the tilt learning and tilt curve calculation are performed only in the area on the inner circumference side at the time of activation, the time required for activation can be shortened. It is possible to improve the efficiency of tilt learning and reduce the time.

  According to a third aspect of the present invention, in the second aspect, after a start-up, when a seek occurs in the area where the tilt learning and the tilt curve calculation are not performed during the start-up, the tilt curve in the area including the target address It is characterized by having means for performing tilt learning at an optical disc radial position necessary for calculation, and calculating a tilt curve in the region based on the learned tilt amount or tilt drive voltage.

This makes it possible to improve the efficiency and time of tilt learning and tilt curve calculation.

  According to a fourth aspect of the present invention, in the third aspect, there is provided means for performing tilt learning and calculating a tilt curve only in a seek before recording is performed in an area including the target address among the divided areas of the optical disk. It is characterized by that. By performing tilt learning and tilt curve calculation only at the seek before recording, tilt learning is performed only in the necessary area when tilt learning is required, so the efficiency of tilt learning and tilt curve calculation Is achieved.

  The invention according to claim 5 is the tilt learning according to claim 2, wherein the tilt learning tilt amount or the tilt drive voltage or the tilt curve data for each tilt learning point is stored for each temperature or temperature range of an arbitrary step. A value storage means is provided.

  By providing the tilt learning value storing means, it is possible to cope with a change in the state of warping of the optical disk due to a temperature change.

  According to a sixth aspect of the present invention, in the fifth aspect, when a predetermined temperature change occurs at the time of startup, a seek is generated in which the target address is a region where tilt learning and tilt curve calculation are not performed at the changed temperature. In this case, the tilt learning is performed at the optical disc radius position necessary for the tilt curve calculation in the area including the target address, and the tilt curve is calculated in the area based on the learned tilt amount or the tilt drive voltage. The value storing means has means for storing the learned value.

  As a result, even if the state of the optical disk warpage changes due to a temperature change, the tilt learning is performed every time a seek occurs, so that an optical disk apparatus capable of performing the tilt learning corresponding to the temperature change can be realized. .

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram of an optical disc apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a recordable optical disk, 2 is a pickup module, and the pickup module 2 is irradiated with light on a spindle motor 3 that rotates the optical disk 1 variably or at a constant rotation, and the optical disk 1. Thus, the optical pickup 4 for recording predetermined information on the optical disc 1 or reading information based on the reflected light of the light irradiated on the optical disc 1, the carriage 5 on which the optical pickup 4 is mounted, and the carriage 5 with the radius of the optical disc 1. A feed unit 6 that is driven to reciprocate in a direction and a feed motor 7 that is a drive source of the feed unit 6 are fixed, and a small / thin optical disc 1 is realized by such a configuration. 8 is an analog signal processing unit, 9 is a servo processing unit, 10 is a motor driving unit, 11 is a digital signal processing unit, 12 is a laser driving unit, and 13 is a controller.

  The operation of the optical disk apparatus configured as described above according to the embodiment of the present invention will be described. In FIG. 1, a pickup module 2 moves a spindle motor 3 that rotates an optical disc 1, an optical pickup 4 for reading an information signal of the optical disc 1, and a carriage 5 on which the optical pickup 4 is mounted in the radial direction of the optical disc 1. The feed section 6 is configured.

  The feed unit 6 includes a feed motor 7, a gear (not shown), a screw shaft (not shown), and the like, and the carriage 5 moves between the inner periphery and the outer periphery of the optical disk 1 by rotating the feed motor 7. It is configured.

  The analog signal processing unit 8 generates a focus error signal and a tracking error signal based on a signal output from an optical sensor (not shown) in the optical pickup 4 in the carriage 5 configured in the pickup module 2. Output to the servo processing unit 9.

  The servo processing unit 9 is an A / D converter that converts the analog signal sent from the analog signal processing unit 8 into a digital signal, a memory that temporarily stores the digital signal converted by the A / D converter, and a memory By an arithmetic circuit that calculates a recorded digital signal or a digital signal sent from an A / D converter by a predetermined method, a D / A converter that converts the digital signal calculated by the arithmetic circuit into an analog signal, or the like Thus, the filter signal processing and various calculation processes are performed by digital calculation so that the light beam spot follows the information track of the optical disc 1. For this reason, various parameter settings and sequence control can be flexibly performed by command from the controller 13.

  The servo processing unit 9 performs control for moving the objective lens mounted on the optical pickup 4 in the focus direction / tracking direction via the motor driving unit 10, transfer control for the feed unit 6, and rotation control for the spindle motor 3. Do.

  During the reproduction operation, the optical pickup 1 is irradiated with light from the optical pickup 4, the reflected light from the optical disk 1 is received by a light receiving element (not shown), and the reproduction output from the optical pickup 4 according to the received light. A signal is input to the digital signal processing unit 11 via the analog signal processing unit 8.

  The digital signal processing unit 11 includes a data slicer, a data PLL circuit, a jitter measurement circuit, an error correction unit, a modulation / demodulation unit, a buffer memory, a laser control unit, and the like, and is effective for the host (HOST in the figure) side. It is transferred as data.

  During the recording operation, the data sent from the host is modulated by the digital signal processing unit 11, and the laser control unit sends a predetermined light source such as a laser (not shown) in the optical pickup 4 via the laser driving unit 12. A current is supplied, the light source is caused to emit light in a pulse shape, for example, and recording is performed on an information track of the optical disc 1. The controller 13 controls the entire optical disk apparatus configured as described above.

  In the lens tilt learning control method according to the present invention, the optical disc area to be subjected to tilt learning is divided into a plurality of radial directions of the optical disc, and at the time of start-up, tilt learning is performed only in the innermost area of the divided optical disc areas. And obtain a tilt approximation curve in this region. When a seek occurs, if tilt learning has already been performed at the seek destination, a tilt drive value corresponding to the position is applied to the tilt actuator based on the learned tilt curve. If tilt learning is not performed at the seek destination when seek occurs, tilt learning is performed in the area that includes the position before seeking to that position, and based on the tilt curve learned in this area. The tilt drive value corresponding to the position is applied to the tilt actuator. When the temperature changes by a certain temperature, tilt learning is performed in the seek destination area.

  FIG. 2 shows a learning condition determination processing procedure in the lens tilt learning control method according to the embodiment of the present invention.

When a learning condition determination instruction is issued (S1), it is determined whether or not tilt learning is performed based on information on the target seek position and its temperature (S2). If the tilt learning has not been performed, the tilt learning condition is satisfied (S3), and the learning condition determination process is terminated (S4). If the tilt learning is performed, the tilt learning condition is not satisfied (not established) (S5), and the learning condition determination process is terminated (S4).

  In order to perform the above processing, a table for storing the learned tilt drive voltage is provided in a matrix format for seek position and temperature. This table will be described later. The learning temperature is a step of about 5 to 15 ° C, and the tilt drive voltage at each point of the temperature is extracted from the table according to the current temperature, and the tilt drive voltage curve (function) with respect to the disk radius is calculated based on that. To do.

  FIG. 3 is a diagram illustrating an example in which tilt learning is performed by dividing the entire area of the optical disk into four parts, and FIG. 4 is a diagram illustrating a tilt calculation method at a position on the optical disk. FIG. 5 is a diagram showing a processing procedure of the lens tilt learning control method according to the embodiment of the present invention.

  As shown in FIG. 3, an optical disc 1 having a tilt or warp is divided into four areas, area 1, area 2, area 3, and area 4, from the inner circumference side to the outer circumference side, and tilt measurement is performed in each area. Made. P1 to P8 are focus low frequency drive voltage measurement points (Fc low frequency drive voltage measurement points), and P12 to P78 are tilt calculation points, that is, two Fc low frequency drives for calculating an average tilt. This is the midpoint between voltage measurement points.

  As shown in FIG. 4, Δh, which is the difference between the lens height h (Pn) at the position Pn and the lens height h (Pn + 1) at the adjacent measurement position Pn + 1, is divided by the interval between Pn and Pn + 1. The tilt expressed by the tilt angle t (n n + 1) is defined as the tilt.

If V (Pn) is the focus drive voltage at Pn and α is the focus sensitivity (displacement / drive voltage),
h (Pn) = V (Pn) × α
It can be expressed as.

Also, if β is tilt sensitivity (tilt amount / drive voltage), V (Pn + 1) is a focus drive voltage at Pn + 1, and Vt (Pn n + 1) is a tilt drive voltage that generates a tilt of t (n n + 1),
t (n n + 1) = Tan ⁻¹ (Δh / l)
= Tan ⁻¹ ((V (Pn + 1) −V (Pn)) × α / l)
= Vt (Pn n + 1) × β
When t (n n + 1) is sufficiently small,
Tant (n, n + 1) ≈ (V (Pn + 1) −V (Pn)) × α / l
Therefore,
Vt (Pn n + 1) = (V (Pn + 1) −V (Pn)) × α / l / β
It becomes.

  Details of the processing procedure of the lens tilt learning control method when the entire area of the optical disk is divided into four will be described with reference to FIG.

  When the tilt learning process is started (S11), it is determined whether or not it is during activation learning (S12). If it is during activation learning, the tilt learning of P12 and P23 is performed (S17), and the tilt learning is performed. The process ends (S28).

When it is not during start-up learning, it is determined whether or not it is before seek of area 1 (S13), and when it is before seek of area 1 is determined whether or not the tilt learning conditions of P12 and P23 are satisfied. (S16). As a result, when the tilt learning conditions of P12 and P23 are satisfied, the tilt learning of P12 and P23 is performed (S17), and the tilt learning process is ended (S28). If the tilt learning conditions of P12 and P23 are not satisfied, the tilt learning process is terminated as it is (S28).

  When it is not before seek of area 1, it is determined whether or not it is before seek of area 2 (S14). When it is before seek of area 2, whether or not the tilt learning conditions of P12 and P23 are satisfied. Is determined (S18). As a result, when the tilt learning condition of P12 and P23 is satisfied, the tilt learning of P12 and P23 is performed (S19), and it is determined whether or not the tilt learning condition of P45 is satisfied (S20). . If the tilt learning conditions of P12 and P23 are not satisfied, it is immediately determined whether or not the tilt learning conditions of P45 are satisfied (S20).

  If it is determined that the tilt learning condition of P45 is satisfied, the tilt learning of P45 is performed (S21), and the tilt learning process ends (S28). If the tilt learning condition of P45 is not satisfied, the tilt learning process is terminated as it is (S28).

  When it is not before seek of area 2, it is determined whether or not it is before seek of area 3 (S15), and when it is before seek of area 2, whether or not the tilt learning condition of P45 is satisfied. A determination is made (S22). As a result, when the tilt learning condition of P45 is satisfied, the tilt learning of P45 is performed (S23), and it is determined whether or not the tilt learning conditions of P67 and P78 are satisfied (S24). When the tilt learning condition of P45 is not satisfied, it is immediately determined whether or not the tilt learning conditions of P67 and P78 are satisfied (S24).

  If it is determined that the tilt learning conditions of P67 and P78 are satisfied, the tilt learning of P67 and P78 is performed (S25), and the tilt learning process ends (S28). If the tilt learning conditions of P67 and P78 are not satisfied, the tilt learning process is terminated as it is (S28).

  When it is not before the seek of area 3, it is determined whether or not the tilt learning conditions of P67 and P78 are satisfied (S26). If it is determined that the tilt learning conditions of P67 and P78 are satisfied, the tilt learning of P67 and P78 is performed (S27), and the tilt learning process ends (S28). If the tilt learning conditions of P67 and P78 are not satisfied, the tilt learning process is terminated as it is (S28).

  FIG. 6 is a diagram showing means for performing tilt learning at Pn and Pn + 1 shown in FIG.

  When an instruction to start tilt learning is given (S31), seek is made to the position of Pn (S32), and the focus low-frequency driving voltage (Fc low-frequency driving voltage) is measured at Pn (S33). Next, seek is performed to the position of Pn + 1 (S34), and the focus low-frequency driving voltage (Fc low-frequency driving voltage) is measured at Pn + 1 (S35). Based on these measurement results, a tilt drive voltage of Pn (n + 1) is calculated (S36).

  Next, a determination is made as to whether or not measurement at Pn + 2 is necessary (S37). If necessary, seek is made to the position of Pn + 2 (S38), and the focus low-frequency drive voltage (Fc low-frequency) is detected at Pn + 2. Drive voltage) is measured (S39). Based on the measurement result, the tilt drive voltage of Pn (n + 1) (n + 2) is calculated (S40), and the tilt learning is terminated (S41). If measurement at Pn + 2 is not necessary, the tilt learning is immediately terminated (S41).

  FIG. 7 shows a timing chart of tilt learning at the time of activation, comparing the present invention with a conventional one based on a tracking error signal (TE signal). FIG. 7A shows the present invention, and FIG. 7B shows the conventional one.

  In the present invention, as shown in FIG. 7A, measurement is sequentially performed at P1, P2, and P3 on the innermost circumference side of the optical disc, learning in area 1 is terminated, and the learning start point is restored. On the other hand, as shown in FIG. 7B, in the conventional apparatus, measurement is sequentially performed for P1 to P8 over the entire surface of the optical disc, and learning for the entire surface is completed and the learning start point is restored. . Therefore, according to the learning method of the present invention, the time required for activation can be significantly reduced.

  FIG. 8 is a diagram illustrating the driving principle of the tilt actuator. FIG. 8A shows a case where tilt driving is not performed, and FIG. 8B shows a case where optimum tilt driving is performed so that the outer peripheral side of the objective lens is raised according to the tilt of the optical disc.

  In FIG. 8A, the objective lens has a relative tilt with respect to the optical disc, and the recording / reproducing characteristics are not optimal. At this time, the driving forces of the Fc actuator 1 (inner peripheral side) and the Fc actuator 2 (outer peripheral side) are both F0 and equal.

In FIG. 8B, the objective lens has no relative tilt with respect to the optical disc, and the recording / reproducing characteristics are optimized. In the case of tilt driving to an upward slope, the driving force F1 of the Fc actuator 1 (inner circumference side) is
F1 = F0-FT
And the driving force F2 of the Fc actuator 2 (outer peripheral side) is
F2 = F0 + FT
It is.

  As described above, the Fc actuator according to the present invention has two driving means on the inner peripheral side (Fc1) and the outer peripheral side (Fc2), and generates the same driving force in both, that is, applies the same voltage. In this case, normal Fc driving without tilt is performed. If the constant driving force (applied voltage) is added to one of the driving forces (applied voltage) and the same driving force (applied voltage) is subtracted from the other, the Fc driving force on the inner and outer sides can be reduced. The balance is lost and tilt occurs. In this actuator system, the Fc actuator and the tilt actuator are combined using the above driving method.

  The driving force of the Fc actuator is generated by arranging a coil (not shown) on the inner peripheral side (Fc1) and the outer peripheral side (Fc2) on the movable part including the objective lens, and applying a voltage to each coil as described above. The Lorentz force generated between the magnet and the magnet fixed to the base (carriage). In addition, it is possible to independently provide a dedicated actuator for generating a tilt. In this case, the Fc actuator is not divided into two parts on the inner peripheral side and the outer peripheral side.

  FIG. 9 is a diagram illustrating a configuration of an Fc low-frequency drive voltage measurement circuit and a tilt actuator control / drive circuit.

The focus error signal (FE signal) is input to the Fc actuator via the Fc actuator driving circuit via the filter shown in FIG. 9, and is also input to the arithmetic circuit via the Fc low-frequency driving voltage measuring circuit. In the Fc low-frequency driving voltage measurement circuit, measurement is performed with a sampling number equal to or greater than one rotation in consideration of a case where tilt fluctuation of the rotation period occurs due to the surface shake of the optical disk. In the arithmetic circuit, the optimum tilt drive voltage at the tilt measurement point from the Fc low range drive voltage,
That is, the tilt drive voltage that provides the best reproduction / recording quality is calculated. Further, a tilt drive voltage curve (function) continuous over the entire surface of the disc is obtained from the tilt drive voltage calculated discretely with respect to the optical disc radius, and the optimum tilt at an arbitrary optical disc radius position is obtained from the curve (function). The driving value can be obtained.

  The calculation result by the calculation circuit is input to the tilt actuator through the tilt actuator control circuit and the tilt actuator drive circuit. In the tilt actuator control circuit, when the destination optical disk radial position information is input, such as when seeking, a tilt drive voltage is set in accordance with the radial position.

  Next, the tilt learning drive voltage temperature table will be described based on (Table 1).

(Table 1) shows how the tilt learning drive voltage temperature table is filled when the following operation is performed over time. The drive voltage Vt shown in (Table 1) indicates learning positions and temperatures in a matrix format, and is described in a format of Vt (learning position-temperature).

  (1) Start-up at a drive temperature of 35 ° C. → Left 12 and tilt 23 are learned and stored in a table.

  (2) After starting at a drive temperature of 45 ° C., seek is first generated in area 2 → tilt 12, tilt 23, and tilt 45 are learned and stored in the table (learning of tilt 12 may be omitted).

  (3) After the start at the drive temperature of 55 ° C., seek occurs in area 3 for the first time → tilt 45, tilt 67, and tilt 78 are learned and stored in the table (learning of tilt 78 may be omitted).

  (4) Seek generation → tilt 67 and tilt 78 is first learned in area 4 after starting at a drive temperature of 65 ° C. and stored in the table.

  As can be seen from (Table 1), there are many areas that do not require learning depending on the drive temperature, and only necessary minimum learning is performed without unnecessary learning that is not actually used. , Learning efficiency can be improved.

  FIG. 10 shows a tilt drive curve when linear interpolation approximation is performed between two learning positions in the radial direction of the optical disk based on the tilt learning drive voltage. P12, P23, P45, P67, and P78 are tilt calculation points in FIG. In the divided tilt learning, an approximated curve is calculated for this curve partially depending on the temperature (or the entire surface when seek occurs in all areas). In the present invention, in order to generate an approximate curve with a small number of learning points, it is desirable to perform linear interpolation between two measurement points.

  INDUSTRIAL APPLICABILITY The present invention can be used as an optical disc apparatus that can perform lens tilt learning control in a short time and can shorten the startup time.

1 is a block diagram of an optical disc apparatus according to an embodiment of the present invention. The figure which shows the learning condition discrimination | determination processing procedure in the lens tilt learning control method which concerns on embodiment of this invention. The figure which shows the example which carries out the tilt learning by dividing the whole area | region of an optical disk into 4 parts The figure which shows the calculation method of the tilt in the position on an optical disk The figure which shows the process sequence of the lens tilt learning control method which concerns on embodiment of this invention. The figure which shows the implementation means of tilt learning FIG. 6 is a timing chart of tilt learning at start-up, showing a comparison between the present invention and a conventional one based on a tracking error signal (TE signal). Diagram showing the drive principle of the tilt actuator The figure which shows the structure of Fc low-pass drive voltage measuring circuit, and a tilt actuator control and drive circuit FIG. 6 is a diagram showing a tilt driving curve when linear interpolation approximation is performed between two learning positions in the radial direction of the optical disk based on the tilt learning driving voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Pickup module 3 Spindle motor 4 Optical pick-up 5 Carriage 6 Feed part 7 Feed motor 8 Analog signal processing part 9 Servo processing part 10 Motor drive part 11 Digital signal processing part 12 Laser drive part 13 Controller

Claims (6)

Lens tilt learning that performs learning control so that the relative angle between the objective lens and the optical disc is maintained in an appropriate state when information is recorded / reproduced by irradiating the optical disc with the laser beam condensed by the objective lens. In the control method, the optical disc area where the tilt learning is performed is divided into a plurality of radial directions of the optical disc, and at the start-up, the tilt learning is performed only in the inner peripheral area of the divided optical disc area, and when seek occurs It is determined whether or not tilt learning is performed at the seek destination, and if tilt learning is not performed, tilt learning is performed in an area including the position before seeking to the position. Tilt learning control method. Tilt actuator in which the objective lens is movable in the tilt direction with respect to the radial direction of the optical disc, tilt drive means for driving the tilt actuator, and objective lens having optimum recording / reproduction characteristics with respect to the disc tilt relative to the objective lens Tilt learning means for learning the tilt amount or tilt driving voltage of the optical disc, tilt curve calculating means for calculating a tilt curve over the entire surface of the optical disk based on the learned tilt amount or tilt driving voltage, and the tilt curve In addition, in an optical disc apparatus comprising a tilt control means for applying a tilt drive voltage at a corresponding disc radius position to the tilt drive means when seeking to an arbitrary optical disc radial position, the optical disc area is divided into a plurality of areas in the radial direction of the optical disc. Divide and tilt only at the inner circumference area at startup Optical disk apparatus characterized by comprising means for performing a tilt curve calculation and. After the start, when a seek occurs in the area where the tilt learning and the tilt curve calculation are not performed at the start, the tilt learning is performed at the optical disc radius position necessary for the tilt curve calculation in the area including the target address. 3. The optical disc apparatus according to claim 2, further comprising means for calculating a tilt curve in the region based on the learned tilt amount or tilt drive voltage. 4. The optical disk apparatus according to claim 3, further comprising means for performing tilt learning and calculating a tilt curve only in a seek before recording is performed in an area including the target address among the divided areas of the optical disk. 3. A tilt learning value storing means for storing tilt learning tilt amount or tilt driving voltage or tilt curve data for each tilt learning point for each temperature or temperature range of an arbitrary step. Optical disk device. Necessary for tilt curve calculation in the area including the target address when a predetermined temperature change has occurred since the start, and a seek using the target address in the area where tilt learning and tilt curve calculation has not been performed at the changed temperature A means for performing tilt learning at an optical disc radius position, calculating a tilt curve in the region based on the learned tilt amount or tilt drive voltage, and storing the learned value in the tilt learned value storing means The optical disk apparatus according to claim 5.

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