JP2001222824A - Optical head feed control method and information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical head feed control method capable of executing stable seek operation and tracking control operation by preventing the occurrence of off-tracking in reproducing or recording the information on an optical information recording medium and an information recording and reproducing device. SOLUTION: A controller 17 compares the captured output level Vlpf of an LPF 16 with a prescribed threshold level Vth and in the case of Vlpf>=Vth, the controller performs an actuator feed by microstep driving of a stepping motor 20 via a stepping motor driver 19 after lapse of a period when jump operation is not carried out during the prescribed pause time. When Vlpf<Vth is thereafter attained after lapse of the prescribed pause time, a jump trigger signal tj is outputted to a jump pulse forming circuit 15. The jump pulse forming circuit 15 forms a signal j and supplies this signal via an adder circuit 13 to a tracking driver. A tracking actuator 9 is driven according to this jump signal j, by which the tracking jump operation is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for condensing light from a light source and recording / reproducing information on a disk-shaped rotating optical information recording medium in a radial direction of rotation of the optical information recording medium. FIELD OF THE INVENTION The present invention relates to an optical head feed control method for performing feed control for moving an optical head and an information recording / reproducing apparatus using the optical head, and in particular, to tracking control for causing an objective lens of the optical head to follow a desired track on an optical information recording medium, The present invention relates to an optical head feed control method and an information recording / reproducing apparatus for performing a track jump control for jumping a light spot to an inner or outer track.

[0002]

2. Description of the Related Art A light beam from a light source is narrowed down to a minute beam light by an optical system having an objective lens, and a recording medium capable of optically recording and reproducing information, that is, recording as minute pits on an optical disk, or an optical disk An optical disk device that reads the pits already recorded on the optical disk device has been developed,
It has been widely used as a storage device for computers and the like. In such a device, for a track following operation and a seek operation for seeking a desired track,
It has a tracking actuator for driving the objective lens in a direction substantially perpendicular to the concentric or spiral track, and an optical head moving means for moving an optical head equipped with the tracking actuator in the radial direction of the optical disk. In the track following operation, the tracking actuator is driven in accordance with the polarity and level of a tracking error signal obtained from the light receiving signal read by the optical head, and the light beam is controlled to always follow the track center.

The optical head moving means drives the entire optical head in the radial direction of the disk so that the objective lens operates near the operation center of the tracking actuator.
By the way, in a seek operation for searching for a desired track, generally, after moving the optical head to the vicinity of the desired track by the optical head moving means, control is performed so that the light beam is positioned on the desired track by a track jump operation or the like. I have. To perform this seek operation at high speed,
It is necessary to move the optical head accurately and at high speed to the vicinity of a desired track by the optical head moving means. For this reason, a stepping motor is usually used as the optical head moving means.

FIG. 6 is a plan view (a) showing a schematic configuration of a DVD-RAM disk, which is a kind of a conventionally used optical disk, and FIG. 6 (b) showing a track configuration by enlarging a portion thereof. In a DVD-RAM disk, a land / groove recording / reproducing method for recording / reproducing information on both a convex track (land track) and a concave track (groove track) formed in advance is adopted. Are replaced every one rotation of the disk. Each track is divided into a plurality of areas (sectors). Further, the disk is also divided into a plurality of areas (zones) in the radial direction, and the number of sectors per track increases in the outer peripheral zone. In the DVD-RAM disk, a large storage capacity is obtained by adopting the above configuration.

As shown in FIG. 6A, a land / groove switching position 30 at which a land track and a groove track are switched is between the last sector of each track and the first sector of the next track, and has a radius of the disk. It is a position aligned with the direction. Also, as shown in FIG.
At the beginning of each sector, a CAPA (complimentary alloca) which is shifted by 1/4 track with respect to the track center and in which address information of the sector is recorded in an uneven pit row.
ted pit address) portion is formed.

FIG. 7 is a partially enlarged view showing the vicinity of the CAPA section of a DVD-RAM disk. As shown in the figure, a plurality of pits are formed in the CAPA section, and address information of the sector is obtained by reading reflected light from the pits. Land / groove switching position 3
0 is in the CAPA section located in the same radial direction of the disk. The user can record information in the user area following the CAPA section, in which land tracks and groove tracks are formed in advance. The land track and the groove track are formed spirally, and are not formed concentrically. When the land track makes a full spiral, it switches to a groove track, and when the groove track makes a full spiral, it switches to a land track. In this way, the tracks are switched in a land, groove, land, groove,.

In this DVD-RAM disk, a push-pull method is usually used as a method for detecting a tracking error signal. According to this method, the polarity of the tracking error signal is inverted between a land track and a groove track. Has become. FIG. 8 is a waveform diagram showing a tracking error signal between a land track and a groove track. As shown in the figure, for example, if it is assumed that a tracking error signal of a positive polarity is generated when the light beam deviates from the track center in the inner circumferential direction in the land track, the light beam is shifted from the track center in the groove track. When it deviates in the inner circumferential direction, a tracking error signal of negative polarity is generated. For this reason, the polarity of the tracking error signal is inverted at the moment of switching between the land track and the groove track, so that the direction of the deviation from the track center and the polarity of the tracking error signal are always the same. The timing of switching between the land track and the groove track at the land / groove switching position 30 is detected by the CAPA unit.

By the way, when the rotational speed of the disk is shifted, such as during a seek operation, address information cannot be obtained from the CAPA section. Therefore, the timing of switching between the land track and the groove track is detected. Can not do it. However, in the DVD-RAM, even in such a state, the pits of the concave and convex portions of the CAPA portion are formed so that the light beam follows the same track again.

FIG. 9 is a diagram showing an operation at a portion where a track switches from a land track to a groove track. In FIG. 9A, if it is assumed that the light beam enters the groove track from the land track, the center of the groove track at the time of entry is at an unstable position for tracking, and the tracking error at the time of entry of the light beam. According to the polarity of the signal (FIG. 9B), the tracking actuator is driven so that the light beam is directed to the center of the land track on either the inner side or the outer side of the groove track.

However, as described above, in the CAPA portion immediately before entering the groove track from the land track, the uneven pit rows formed there are formed by being shifted from these tracks by 1/4 track in the disk radial direction. Therefore, the pit train generates a tracking error signal such that the light beam apparently deviates from the track center toward the outer periphery of the disk. Therefore, tracking control is performed to return the light beam to the inner circumferential direction of the disk.

As a result, the tracking actuator is accelerated in the inner circumferential direction of the disk, and at the position of the groove track immediately after passing the CAPA portion, the light beam is shifted from the track center in the inner circumferential direction of the disk. As a result, a tracking error signal for driving the actuator in the inner circumferential direction of the disk is generated in the portion where the land track is switched to the groove track, and the light beam is drawn toward the land track on the inner circumferential side of the groove track. Thus, the light beam follows the same land track as before one round of the disk.

FIG. 10 is a schematic configuration diagram showing an optical head driving mechanism for moving an optical head using a stepping motor in a radial direction. In the figure, stepping motor 2
At 0, a drive shaft called a lead screw 23 having a spiral groove formed at a constant pitch P is attached. The optical head 3 is mounted so as to engage with this groove and move in a direction perpendicular to the optical axis of the objective lens 8 (that is, in a disk radial direction (not shown)). Thus, each time the stepping motor 20 makes one rotation, the optical head 3 moves in the radial direction of the disk by the pitch P of the groove of the lead screw 23.

The number N of pulses applied to the stepping motor
Is determined according to the basic step angle θ ° (degree), and Φ = N ·
It is given by θ. Also, the moving amount Δ of the optical head at this time
Since X is given by ΔX = P · Φ / 360 = P · N · θ / 360, the optical head 3 moves in proportion to the given pulse number N. Thus, in the optical head driving mechanism using the stepping motor 20, the optical head 3
Is determined by the number N of pulses applied to the stepping motor 20, and the error does not accumulate according to the number N of pulses even if the number N of pulses input increases. There is no need to detect with a sensor, etc.
The feature is that the optical head 3 can be accurately moved to the vicinity of a desired track by the open loop.

In order to move the optical head 3 in the radial direction with high accuracy, it is necessary to reduce the basic step angle θ of the stepping motor 20 and the groove pitch P of the lead screw 23. On the other hand, to speed up the seek operation,
It is necessary to increase the feed amount per step or increase the frequency of the pulse. It is necessary to increase the basic step angle θ and the groove pitch P of the lead screw 23 in order to increase the feed amount per step (P · θ). Will not be compatible with

When the pulse frequency is increased, the torque generated by the stepping motor 20 decreases,
Above a predetermined pulse frequency, a phenomenon called step-out occurs in which the stepping motor 20 does not rotate even if a pulse is applied. When this step-out phenomenon occurs, there is a problem that the number of applied pulses and the moving distance of the optical head 3 do not match, and the accuracy of the moving distance deteriorates.

As a method for achieving both high precision of the optical head feed and high speed of the seek operation, a driving method of a stepping motor called a micro step driving method is known. In this micro-step drive system,
By changing the amplitude of the pulse applied to the stepping motor, a rotation angle smaller than the basic step angle can be obtained. FIG. 11 shows a waveform of a driving signal and a measurement result of a pickup moving amount when a two-phase stepping motor used in an optical disk device is driven by a two-phase excitation driving method (a) and a micro step driving method (b). It is.

The two-phase excitation driving method is the most general driving method for a stepping motor, and has a phase of 9%.
This is a driving method in which a stepping motor is rotated by alternately applying two pulse signals shifted by 0 °. Each time the phase of the drive signal of each phase is shifted by 90 °, the stepping motor rotates by one step. Therefore, the stepping motor rotates by four steps in one cycle (360 °) of the drive signal.

On the other hand, in the micro-step drive system, the phase of a drive signal is divided into a plurality of phases, and a drive current having an amplitude corresponding to each phase is caused to flow through a coil of a stepping motor. A pseudo sine wave whose phase is shifted by 90 ° is formed. Thereby, the stepping motor can be rotated at an angle smaller than the basic step angle.

[0019]

However, when the stepping motor is minutely rotated by the step feed,
A large acceleration occurs in the optical head, which causes the following problems. That is, first, if such a step feed is performed at the time of a track jump, the track jump cannot be accurately performed.

Here, the track jump operation will be described with reference to FIG. However, FIG. 12A shows a case where no step feed is performed during a track jump, and FIG. 12B shows a case where step feed is performed during a track jump. First, a case where no step feed is performed at the time of a track jump will be described with reference to FIG.

As shown in (a), when the jump trigger signal tj is given at time t ₀ , as shown in (c),
The jump trigger signal tj is generated at the level “H”, which causes the tracking actuator to (e).
Is supplied, and as shown in (f), the tracking actuator moves the light beam in the direction of the movement destination track at the acceleration Aj. Since this light beam shifts from the track that has been following up along with the movement, the tracking error signal detected increases as shown in (b), and the intermediate position (to the next track) (Half to the destination track).

Time t ₁ when time Tj has elapsed from time t ₀
When the tracking error signal becomes 0, it means that the light beam has moved half of the distance to the movement destination track, and by detecting this, the detection time (time t
₁ ) Invert the polarity of the jump signal j as shown in (c). As a result, as shown in (e), the polarity of the tracking actuator drive signal tc is also inverted, and the tracking actuator decelerates the moving light beam by applying acceleration (-Aj). By performing this deceleration for the same time Tj as the above acceleration, the light beam reaches the adjacent track at the time t ₂ at the time t _2, and the relative speed of the light beam to the track at this time is reduced. I have.

Here, the tracking control based on the ordinary feedback is to prevent the light beam from deviating from the center of the track. If the tracking control is performed when performing the track jump, the track jump is prevented. Works. Therefore, during the track jump operation (time t _{0 to} t ₂ ), as shown in (d), the tracking control by the feedback is not performed.

At time t ₂ , the tracking control is turned on (d). At this time, since the light beam is located substantially at the center of the adjacent track and the relative speed with respect to the track is small, (b) is shown. Thus, the tracking error signal is also sufficiently small. For this reason, as shown in (e), the drive signal tc of the tracking actuator for tracking control is small, and normal tracking control is immediately performed, so that the light beam stably follows the adjacent track. .

On the other hand, when stepping is performed by a stepping motor during a track jump, FIG.
In (b), as shown in (f), as a result of this step feed, a unidirectional acceleration As due to the movement of the optical head is applied to the tracking actuator, and a track jump is performed in this state. .

At time t ₀ , a jump trigger signal tj (a)
The jump signal j (c) and the drive signal tc (e) of the tracking actuator after the application of
As in the case of (a), as shown in (f), in addition to the accelerations Aj and (-Aj) due to the jump signal j, the tracking actuator has the acceleration due to the movement of the optical head.
As will be added, acceleration (Aj + As) and deceleration (-Aj + As)
And the balance between them will be lost. Thus, at time t ₂ the track jump is completed, not the relative speed between the light beam and the track is small, the light beam even after the time t ₂ is Yuki moves it away from the centers of adjacent tracks,
Even the tracking control is turned on at time t _2, the larger the tracking error (B) is, the problem that arises and may fail to track jump.

Also, as described above, even in a state where the switching timing between the land track and the groove track cannot be detected in the DVD-RAM disk, the CA is so controlled that the light beam can follow the same track.
An uneven pit row is formed in the PA portion. However, at the time of switching from land track to groove track,
When the tracking actuator is accelerated in the outer peripheral direction of the disk by the micro-step drive of the stepping motor and the optical head moves, the light beam is shifted from the track center toward the outer peripheral direction at the position of the groove track past the CAPA section. . At this time, since the track switching timing is not detected, the polarity of the tracking error signal is not inverted.

As a result, a tracking error signal for driving the tracking actuator in the outer peripheral direction of the disk is generated, the light beam is drawn toward the land track on the outer peripheral side of the disk, and the track followed by the light beam is shifted. There is. In the worst case, when the optical head is moved by the micro-step driving of the stepping motor, the tracking is often lost in the land / groove switching unit due to the acceleration applied to the actuator, and it takes much time to perform the tracking again. There was a problem.

The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to prevent occurrence of tracking loss when reproducing or recording information on an optical information recording medium. It is another object of the present invention to provide an optical head feed control method and an information recording / reproducing apparatus capable of performing stable seek operation and tracking control operation.

[0030]

In order to solve the above-mentioned problems, the present invention condenses a light beam from a light source on a track having a servo polarity switching portion formed on a rotating optical information recording medium. When the optical head for recording or reproducing the data is optically moved in the radial direction of the optical information recording medium dynamically by the optical head feeding mechanism, the light beam condensing point is not at least in the servo polarity switching portion of the track. Sometimes, the optical head is fed, and the servo polarity switching unit is, for example, a land / groove switching unit. Further, the servo polarity switching unit is adjacent to the light beam converging point by moving the objective lens of the optical head. The optical head feed is performed after a predetermined time has elapsed since the track jump control to the track was performed, or a predetermined time after the optical head feed was performed. After There has elapsed, in which to perform the track jump control.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of an optical head feed control method and an information recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an optical disk such as a DVD-RAM disk on which spiral land tracks and groove tracks are formed, 2 denotes a spindle motor for rotating and driving the optical disk 1, and 21 denotes a spindle for supplying a drive current to the spindle motor 2. The driver 22 outputs a control signal to the spindle driver 21 to
Is a spindle control circuit for controlling rotation at a predetermined rotation speed. An FG pulse having a frequency proportional to the number of rotations of the spindle motor 2 is output from the spindle driver 21 and is taken into the controller 17.

Reference numeral 3 denotes an optical head arranged so as to be movable in the radial direction of the optical disk 1. Reference numeral 4 denotes a light emitting element composed of a semiconductor laser for outputting a light beam. Reference numeral 5 denotes a plurality of light receiving sections.
In this example, the light receiving element is composed of a photodiode that detects the reflected light from the optical disk 1 and is divided into two parts. A half mirror 6 transmits a part of the incident light and reflects the remaining light. A collimator lens for converting the outgoing light into a parallel light beam, or converging the parallel light beam reflected by the optical disc 1 to the light receiving element 5, and 8 for converging the parallel light beam from the collimator lens 7 to the optical disc 1, or And 9 is a tracking actuator for controlling the track position of the light beam by moving the objective lens 8 in the disk radial direction.

Reference numeral 11 denotes a light receiving signal generated by the light receiving element 5 and, based on the light receiving signal, a signal such as a tracking error signal te indicating a deviation between the light beam irradiated on the optical disk 1 and the track center. A signal generation circuit for generating 1
Reference numeral 2 denotes a tracking control circuit that generates a tracking control signal based on the tracking error signal te supplied from the signal generation circuit 11, and reference numeral 13 denotes a tracking control signal output from the tracking control circuit 12 and an output from a jump pulse generation circuit 15 described later. The adder circuit 14 adds the jump signal j with the light beam according to the tracking actuator drive signal tc supplied from the adder circuit 13 so that the light beam follows the track or according to the jump signal j. Tracking actuator 9 so that a track jumps to a track
This is a tracking driver that drives.

Reference numeral 15 denotes a jump pulse generating circuit for generating a jump signal j output to the adder circuit 13;
Is an LPF that passes only the low frequency components of the tracking control signal output from the tracking control circuit 12.
(Low Pass Filter), 17 is a controller for controlling the entire information recording / reproducing device, 18 is a device for receiving a reproduced signal from the signal generating circuit 11 and transmitting the reproduced signal to a pit of a CAPA section formed in advance on the optical disc 1. An address reproduction circuit for extracting a corresponding address information signal and outputting the address information signal to a controller 17, a stepping motor driver 19 for electrically driving a stepping motor 20 described below under the control of the controller 17, It is a stepping motor that moves in the direction.
FIG. 1 omits parts of the optical head that are not necessary for the description of the present invention. Further, the arrangement of the components constituting the optical head does not necessarily have to be as shown in the drawing, and the components themselves may have the same function.

Next, the operation of this embodiment will be described. The light beam emitted from the light emitting element 4 controlled to have a predetermined output by the laser driver 10 is transmitted to the half mirror 6,
The light is irradiated onto the optical disc 1 via the collimator lens 7 and the objective lens 8. A spiral track is formed on the recording / reproducing surface of the optical disc 1. The reflected light from the optical disk 1 passes through the objective lens 8, the collimator lens 7, and the half mirror 6 again, and enters the respective light receiving portions of the light receiving element 5. The light receiving signal of each light receiving section of the light receiving element 5 is output to the signal generation circuit 11. The signal generation circuit 11
Based on these light receiving signals, the tracking error signal te and CA
A reproduction signal corresponding to the pit of the PA section is generated, and the tracking control circuit 12 and the address reproduction circuit
To supply.

The address information signal extracted by the address reproducing circuit 18 is output to the controller 17. The controller 17 determines the position of the light beam on the optical disc 1 (accurately, the track on which the light beam is irradiated) based on the address information signal from the CAPA unit.
When a land / groove switching position is detected (that is, when address information of the first sector of the track is detected), a jump trigger signal jt is generated and output to the jump pulse generation circuit 15. Jump pulse generation circuit 15
Is added to the tracking control signal output from the tracking control circuit 12 via the adding circuit 13 and supplied to the tracking driver 14. When the tracking driver 14 drives the tracking actuator 9 by the jump signal j, a track jump operation for forcibly moving the light beam to an adjacent track is performed. As a result, the action of the CAPA section that switches between the land track and the groove track forces the light beam to return to the original track and to move to the next adjacent track.

The tracking control signal output from the tracking control circuit 12 is supplied to a tracking driver 14 via an adding circuit 13, and the tracking driver 14 drives the tracking actuator 9 so that the light beam follows a predetermined track. I do. in this case,
In the address reproducing circuit 18, when the address information of the first sector at the time of switching between the land track and the groove track is detected by the address information from the signal generating circuit 11, the polarity of the tracking error signal te is inverted. As a result, the light beam forcibly moved to the next adjacent track by the above track jump stably follows this track by the tracking control based on the tracking error signal te whose polarity has been inverted. .

In this manner, the light beam follows the tracks sequentially in the order of land, groove, land, groove,.... Further, the tracking control signal output from the tracking control circuit 12 is the LPF 1
6 is also output to the controller 17. The controller 17 detects a deviation of the objective lens 8 from the actuator operation center position based on the output level Vlpf of the LPF 16, and controls the objective lens 8 via the stepping motor driver 19 so that the objective lens 8 always operates at the operation center position of the tracking actuator 9. To drive the stepping motor 20 by microstepping.

In this way, the light beam moves in the radial direction of the optical disc 1 while following the track,
The optical head also moves. In order to record information on a desired track on the optical disc 1, it is necessary to move the optical head 3 to search (seek) for the desired track.

To search for a desired track on the optical disk 1, the optical head 3 is moved by operating the stepping motor 20, and after roughly aligning the optical head 3, the tracking actuator 9 is operated and the objective lens 8 is moved. By shaking, the light beam causes a track jump to perform fine positioning. The accuracy of the alignment by the stepping motor 20 is approximately 2 near the target track (land track or groove track).
It is on the order of being located on any of the zero tracks.
Therefore, from that position, the tracking actuator 9
Is operated to swing the objective lens 8, thereby causing a track jump to be performed, so that the light beam is positioned on the target track.

FIG. 2 is a schematic diagram showing the correlation between the objective lens 8 and the actuator 9 when searching for a desired track on the optical disk 1. Fig. 2 (a) shows "Before actuator feed".
Is a state in which the objective lens 8 is swung so that the light beam is positioned on the target land track (or groove track). In this state, the objective lens 8
Deviates from the position of the operation center of the tracking actuator 9. If this state is left as it is, the tracking control operation is unstable and the tracking is easily lost.
As shown in “b” after “actuator feed”,
By operating the stepping motor 20, the entire optical head 3 including the tracking actuator 9 is moved so that the objective lens 8 comes to the operation center position of the tracking actuator 9. Hereinafter, this feed operation is referred to as actuator feed.

An FG pulse having a frequency proportional to the rotation speed of the spindle motor 2 is generated from the spindle driver 21 and output to the controller 17. This FG pulse is always a fixed number (here, 6) during one rotation of the optical disc 1.
To occur). Therefore, when the optical disk 1 is loaded, the timing of generation of each FG pulse and the absolute position on the optical disk 1 have a one-to-one correspondence, whereby the absolute position on the optical disk 1 corresponding to the FG pulse is determined. be able to.

Therefore, at the time of starting reproduction of the optical disk 1, the stepping motor 20 is operated to move the optical head 3 so that the light beam is positioned, for example, on the substantially innermost track of the optical disk 1, and thereafter, the spindle The control circuit 22 controls the spindle motor 20 so that the rotation speed of the optical disc 1 becomes a predetermined rotation speed when the light beam is at the position of the innermost track. When the rotation speed of the optical disk 1 reaches the predetermined rotation speed, a tracking servo is applied so that the light beam follows the innermost land track (or groove track).

In this state, the address information is read from the CAPA section of the innermost track of the optical disk 1 in this state, and based on this, the detection timing of the land / groove switching section 30 (accordingly, the polarity inversion timing of the tracking error signal te) ) Can be measured. Detection timing information of the land / groove switching unit 30;
By comparing the absolute position irradiated with the light beam on the disk 1 determined from the FG pulse, the optical disk 1
During one rotation, it is possible to determine between which FG pulse and which FG pulse the land / groove switching unit 30 exists. Since the positions at which the land track and the groove track are switched are aligned in the radial direction of the optical disc 1, the positional relationship between the FG pulse and the land / groove switching unit 30 is such that the light beam is at any position from the inner circumference to the outer circumference of the optical disc 1. Even so, it is constant.

FIG. 3 shows a land / groove switching signal, an FG count value, an FG pulse, a one-phase and two-phase drive signal of the spindle motor 20 and an LPF1 at the time of actuator feed.
6 is a timing chart showing a specific example of an output signal relationship of No. 6; Here, as described above, it is assumed that six FG pulses are generated for one rotation of the optical disk 1, and the first, second,...
And This example shows a case where the land / groove switching unit 30 is provided between the third FG pulse and the fourth FG pulse. When the output level Vlpf of the LPF 16 is equal to or higher than the predetermined threshold Vth, the controller 17
It is determined that the deviation from the actuator operation center position is large. If this deviation is large, the controller 17
Drives the actuator such that the objective lens 8 approaches the center of operation of the actuator by microstep driving the stepping motor 20.

At this time, the timing for performing the micro-step driving is the period of the land / groove switching unit 30 (therefore, the polarity of the tracking error signal te is inverted during this period), that is, from the generation of the third FG pulse to the fourth FG.
Avoid the period until the pulse is generated. As a result, the rotation speed of the optical disk 1 immediately after the seek operation of the desired track is changed to the optical disk 1 where the light beam is located at that time.
Even before the rotation speed corresponding to the upper zone is settled, even when the address information is not obtained, it is possible to avoid the tracking loss when the land / groove switching unit 30 detects. When the controller 17 performs such an actuator feed, the optical head 3 moves in a direction in which the deviation of the objective lens 8 from the actuator operation center position decreases, and as a result, the output level Vlpf of the LPF 16 decreases.

Next, the operation of the track jump of this embodiment will be described. 4 is a flowchart showing the track jump processing of this embodiment, and FIG. 5 is a tracking error signal te, a jump trigger signal tj, a one-phase and two-phase drive signal of the spindle motor 20 and an LPF at this time.
FIG. 14 is a signal waveform diagram showing 16 output signals Vlpf.

In FIG. 4, first, L is detected to detect a deviation of the objective lens 8 from the actuator operation center position.
The output level Vlpf of the PF 16 is taken into the controller 17 (step 1). The output level Vlpf of the taken LPF 16 is compared with a predetermined threshold level Vth (step 2). If Vlpf <Vth, it is determined that the deviation of the objective lens 8 from the center of the actuator operation is small. A jump trigger signal tj is output to the generation circuit 15 (step 3).

The jump pulse generation circuit 15 having received the jump trigger signal tj generates a jump signal j and outputs it to the addition circuit 13. The jump signal j is supplied to the tracking driver 14, and the tracking driver 14 drives the tracking actuator 9 according to the jump signal j to perform a track jump operation. In this way, by repeating the track jump processing, the deviation of the objective lens 8 from the actuator operation center position increases. When this deviation increases, LPF
The 16 output levels Vlpf also increase.

In step 2, as shown in FIG. 5, when Vlpf ≧ Vth, it is determined that the deviation of the objective lens 8 from the actuator operation center position is large.
After a period in which the jump operation is not performed for a predetermined pause time Tjb (FIG. 5) (step 4), the controller 17
Drives the stepping motor 20 via the stepping motor driver 19 by micro-stepping to perform actuator feed (step 5). As a result, the optical head 3 moves in a direction in which the deviation of the objective lens 8 from the actuator operation center position decreases, and as shown in FIG.
The output level Vlpf of the PF 16 decreases. After a predetermined pause time Tja (FIG. 5) elapses after the actuator is fed (step 6), the processing from step 1 is repeated again.

It should be noted that the predetermined pause time Tjb is, for example, equal to or longer than the time until the response of the previous track jump substantially converges. The pause time Tja is, for example, equal to or longer than the time until the response of the actuator feed by the micro-step drive converges. As described above, by not performing the actuator feed by the stepping motor 20 before and after the track jump operation, a stable track jump can be performed.

[0052]

According to the present invention described above, when the tracking control, the track jump control, and the optical head feeding are performed, the optical head is not located at the servo polarity switching section of the optical information recording medium. For example, after a predetermined time has elapsed since the track jump control was performed, the optical head feeding is performed, or after a predetermined time has elapsed since the optical head feeding is performed, the track jump control is performed. Since it is performed, when reproducing or recording information on the optical information recording medium, it is possible to prevent occurrence of tracking loss and to perform a stable seek operation and tracking control operation.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an optical head feed control method and an information recording / reproducing apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a correlation between an objective lens and an actuator when searching for a desired track on an optical disc.

FIG. 3 is a timing chart showing a specific example of a relationship between various signals at the time of actuator feed.

FIG. 4 is a flowchart showing a track jump process.

FIG. 5 is a signal waveform diagram showing a specific example of a relationship between various signals during a track jump process.

6A is a plan view showing a schematic configuration of a DVD-RAM disk according to a conventional example, and FIG. 6B is an enlarged view of the portion showing a track configuration.

FIG. 7 is a partially enlarged view showing a portion near a CAPA portion of a DVD-RAM disk.

FIG. 8 is a waveform diagram showing a tracking error signal between a land track and a groove track.

FIG. 9 is a diagram illustrating an operation at a portion where a track switches from a land track to a groove track.

FIG. 10 is a schematic configuration diagram illustrating an optical head driving mechanism that moves the optical head in a radial direction.

FIG. 11 shows a waveform of a driving signal and a measurement result of a pickup moving amount when a two-phase stepping motor is driven by a two-phase excitation driving method (a) and a micro step driving method (b).

FIG. 12 is a signal waveform diagram showing various signal waveform shapes during a track jump operation.

[Explanation of symbols]

 Reference Signs List 1 optical disk (information recording medium) 2 spindle motor 3 optical head 4 light emitting element (semiconductor laser) 5 light receiving element (photodiode) 7 collimator lens 8 objective lens 9 tracking actuator 11 signal generation circuit 12 tracking control circuit 13 addition circuit 15 jump pulse Generation circuit 16 LPF (Low Pass Filter) 17 Controller 18 Address reproduction circuit 20 Stepping motor 22 Spindle control circuit 30 Land / groove switching position

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D117 AA02 AA08 EE09 EE17 FF25 FF30 JJ06 JJ10 5D118 AA13 BA01 CA14 CD03

Claims (7)

[Claims] 1. An optical head for recording or reproducing information by condensing a light beam from a light source on a track having a servo polarity switching unit formed on a rotating optical information recording medium by an optical head feed mechanism. An optical head feed control method for feeding an optical head that moves dynamically in the radial direction of an information recording medium, wherein the optical head feed is performed when the focal point of the light beam is not at least in the servo polarity switching unit of the track. An optical head feed control method characterized in that: 2. The servo polarity switching section according to claim 1, wherein the servo polarity switching section is a land / groove switching section that switches from a convex land track to a concave groove track or from the groove track to the land track. Optical head feed control method. 3. A signal according to claim 1, wherein a signal synchronized with the rotation of the optical information recording medium is detected, and the fact that the focal point is in a period not including the servo polarity switching unit is based on the signal. An optical head feed control method, wherein the optical head feed is detected during the period. 4. The optical head according to claim 1, wherein the optical head is moved by moving an objective lens of the optical head to a track jump of a converging point of the light beam to an adjacent track. An optical head feed control method, wherein the control is performed after a predetermined time has elapsed since the control was performed. 5. The optical head according to claim 1, wherein a track jump control for moving a focus point of the light beam to an adjacent track by moving an objective lens of the optical head is performed. An optical head feed control method, wherein the control is performed after a predetermined time has elapsed after the feed. 6. An information recording / reproducing apparatus, wherein the optical head feed is performed by the optical head feed control method according to claim 1. 7. The information recording / reproducing apparatus according to claim 6, wherein the optical head feed mechanism is constituted by a stepping motor.