JP2003317270A - Optical disk drive - Google Patents

Abstract

(57) [Problem] To provide an optical disc device capable of improving the moving speed of an optical pickup in a seek operation and ensuring the stability of the seek operation. SOLUTION: In a seek operation by a stepping motor 13, a driving pulse of the stepping motor 13 is controlled or a focus servo gain is changed while monitoring a focus error signal, thereby generating a driving operation of the stepping motor 13. And the vibration given to the condenser lens of the optical pickup 11 is also suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for controlling the positioning of an optical pickup when reading / writing data from / to a disk recording medium by using a stepping motor.

[0002]

2. Description of the Related Art In recent years, an optical disk device has been widely used for reading a data signal recorded on a recording surface of a disk-shaped recording medium or writing data on the recording surface of the disk-shaped recording medium by a light beam. Recently, DVD (Digital) capable of reading and writing large-capacity data
Versatile Disk) is drawing attention as an important recording medium.

A DVD that realizes such a large capacity
Is the track spacing on the disc compared to CD (hereinafter
The track pitch (which is called the track pitch) is small, and it is necessary to move the optical pickup to the target position more accurately and at high speed, and it is possible to perform high-precision positioning for positioning control of the movement of the optical pickup. Are often used.

The optical disk device using the stepping motor for the positioning control during the movement of the optical system pickup will be described below. FIG. 7 is a block diagram showing the configuration of an optical disk device which has been conventionally used. As shown in FIG. 7, the pickup 11 including the condenser lens is attached to the lead screw 12. The lead screw 12 is directly connected to the stepping motor 13, and by driving the stepping motor 13, the lead screw 12 rotates. The rotational movement of the lead screw 12 is converted into the linear movement of the pickup 11, and as a result, the pickup 11 causes the optical disk 1 to move.
4 can be moved in the radial direction.

The general driving method of the stepping motor 13 is basically the timing shown in FIGS. 8 and 9 as an output signal from the A-phase setting D / A converter 15 and the B-phase setting D / A converter 16. The current values of the A phase and B phase of the stepping motor 13 are changed according to the waveform of the excitation pulse shown in the chart. This change in the current value of the A phase and the B phase changes the magnetic field generated from the four magnetic poles A +, A−, B +, B− of the stepping motor 13 shown in FIG.
The rotor 21 is rotated.

The acceleration and deceleration of the rotation speed of the stepping motor 13 are realized by changing the response frequency indicated by the exciting pulse change interval. Further, the constant speed rotation of the stepping motor 13 is realized by keeping the excitation pulse interval constant so that the response frequency does not change.

As the excitation method for driving the stepping motor 13, there are a two-phase excitation drive method and a 1-2-phase excitation drive method. As the excitation pulse, FIG. 8 shows the excitation in the two-phase excitation drive. FIG. 9 shows a timing chart of pulses, and FIG. 9 shows a timing chart of excitation pulses in the 1-2 phase excitation drive.

In the 1-2 phase excitation, there are one phase driving (dotted line arrow portion in FIG. 9) and two phase driving (solid line arrow portion). When driven in the 1-phase, for example, a current is passed only in the A-phase in FIG. 10 to magnetize the magnetic poles to support the rotor 21 in the 1-phase. In both phase B and phase B, a current is passed to magnetize the magnetic poles and support the rotor in two phases. Therefore, when the magnetic poles are changed to rotate the rotor,
There is a difference between the torques generated in the first phase and the second phase (that is, the force that pulls the rotor to the target position).

Therefore, the 1-2 phase excitation is disadvantageous in increasing the rotation speed (that is, increasing the above-mentioned response frequency). On the other hand, in the two-phase excitation, since the two-phase magnetic poles are always changed to cause the rotational motion, the generated torque is constant, and therefore it is advantageous in increasing the rotation speed (increasing the response frequency) compared to the 1-2-phase excitation. is there.

However, in the two-phase excitation, the distance moved by one pulse is large (corresponding to two pulses in the 1-2 phase excitation),
Particularly in a low response frequency portion, the vibration generated from the stepping motor becomes large, which may adversely affect the focus control and tracking control of the pickup 11.

From the above, according to the conventional method, only the 1-2 phase excitation method is used, or the 1-2 phase excitation method is used in the low response frequency portion and the 2-phase excitation method is used in the high response frequency portion. Method is used.

Now, the seek operation using the stepping motor will be described with reference to FIGS. 11 and 12. First, the distance from the current address and the target address to the target position is calculated (step S01), and the total number of steps of the stepping motor is calculated from the distance (step S0).
2). For example, the total number of steps to the target position can be obtained by dividing the obtained distance to the target position by the movement amount per step of the stepping motor. From the total number of steps, the number of steps for acceleration, constant speed, and deceleration is obtained (step S03). For example, it can be obtained by dividing the total number of steps into three equal parts.

Next, it is judged whether or not the number of acceleration steps exceeds a predetermined threshold value (step S04).
Two-phase excitation and a seek operation using two-phase excitation or a seek operation using only 1-2 phase excitation are determined (step S05 and step S06). The seek operation is as shown in FIG.
The trapezoidal drive is provided with an acceleration region, a constant velocity region, and a deceleration region, and seek operation is performed from the current position to the target position.

As described above, at the low response frequency in the seek operation, the 1-2 phase excitation with less vibration generated from the stepping motor is used, and at the high response frequency to increase the maximum response frequency ft in FIG. 12, the 2-phase excitation is used. Thus, in the seek operation using the stepping motor, it is possible to improve the moving speed of the pickup and ensure the stability of the seek operation.

[0015]

However, in the 1-2 phase excitation used in the conventional seek operation, the torque generated is not constant, and therefore the inclination at the dashed line in FIG. 13 at the time of acceleration cannot be increased so much. . Therefore, there has been a problem that there is a limit in reducing the moving time of the optical pickup from the current position to the target position.

If two-phase excitation is used in the entire region of FIG. 13, the generated torque is constant, so that
As indicated by the solid line, the inclination at the time of acceleration can be increased, and the moving time of the optical pickup from the current position to the target position can be shortened. However, the movement distance per pulse is large, and the vibration generated from the stepping motor becomes large especially in the low response frequency portion, which may adversely affect the lens control of the optical pickup.

From the above, in the seek operation using the stepping motor, the low response frequency portion is 1-2.
The phase excitation is used, and the part where the seek operation is performed using the 1-2 phase excitation causes the movement time of the optical pickup to be delayed.

The present invention solves the above-mentioned conventional problems, and provides an optical disk device capable of improving the moving speed of the optical pickup in the seek operation and ensuring the stability of the seek operation.

[0019]

In order to solve the above-mentioned problems, the optical disk apparatus of the present invention monitors the focus error signal FE generated from the pickup in the seek operation to the target position in the stepping motor, When the FE signal exceeds a predetermined range, the FE signal operates as follows. (1) The exciting current flowing to the stepping motor is changed within a predetermined range. (2) The response frequency of the drive pulse of the stepping motor is changed within a predetermined range. (3) Change the servo gain of the optical disk.

As described above, in the seek operation by the stepping motor, the drive pulse of the stepping motor is controlled or the focus servo gain is changed while monitoring the focus error signal, so that the stepping motor is driven. Suppress vibration,
Vibrations given to the lens of the optical pickup can also be suppressed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical disk device according to claim 1 of the present invention is a light condensing device for converging a laser beam on the surface of a track formed on a disc-shaped recording medium and having information recorded thereon to generate a focal point. An optical pickup that includes a lens and an actuator that drives the condenser lens, irradiates the recording surface of the recording medium with the laser light, and a unit that detects the amount of defocus of the laser light with respect to the surface of the track. Focus control means using the amount of focus deviation on the surface of the track, means for detecting the amount of deviation of the focus from the center of the track, and the amount of focus deviation from the center of the track Tracking control means, stepping motor for feeding and driving the optical pickup, and excitation system for the feeding driving of the stepping motor The total number of steps for feeding and driving the stepping motor is calculated from this moving distance based on the selection means for selecting the 2-phase excitation method and the 1-2-phase excitation method, and the current position and target position of the optical pickup. The control means includes a calculating means, a means for applying an exciting current to an exciting coil of the stepping motor, and a controlling means for controlling the exciting current. The controlling means controls the two-phase excitation in which the stepping motor is selected by the selecting means. While driving the optical pickup by the method, while detecting the deviation amount of the focus of the laser light, if the deviation amount exceeds a predetermined range,
The excitation current to the stepping motor is changed within a predetermined range.

According to this structure, it is possible to reduce the influence on the focus control of the optical pickup which is generated by the vibration accompanying the feed drive of the stepping motor during the seek operation by the stepping motor. The seek operation can be performed only by the two-phase excitation method capable of increasing the driving speed, the moving speed of the optical pickup in the seek operation is improved, and the stability of the seek operation is guaranteed.

An optical disk device according to a second aspect is the optical disk device according to the first aspect, wherein when the exciting current is changed, a storage means for storing the changed exciting current is provided, and the control means is When the exciting current to the stepping motor is changed, the changed exciting current is stored in the storage means, and when the optical pickup is driven again, the stored exciting current is used for driving.

According to this structure, when the exciting current is changed during the seek operation, the exciting current is stored, and the seek operation is performed using the changed exciting current from the next seek operation. From the start of the seek operation, the influence of the vibration generated by the stepping motor on the optical pickup can be reduced, and the stability of the seek operation is ensured.

An optical disk device according to a third aspect of the present invention is the optical disk device according to the first aspect, further comprising storage means for storing an exciting current before the optical pickup is driven and driven, and the control means includes the optical pickup. The exciting current is stored in the storage means before the feeding drive of No. 1 and is returned to the stored exciting current at the end of the feeding drive of the optical pickup.

According to this structure, in the feed drive of the optical pickup, the optimum excitation current is used in the seek process, and at the end of the feed drive for the seek process, it is optimal in the processes other than the seek process before the feed drive. The stability of the operation other than the seek process is secured by returning to a different exciting current.

An optical disk device according to a fourth aspect of the present invention is the optical disk device according to the first aspect, wherein even if the control means reduces the exciting current to a lower limit thereof within a predetermined range of the exciting current, When the deviation amount of the focus of the laser light exceeds a predetermined range, the selection means switches the excitation method from the two-phase excitation method to the one-two-phase excitation method.

According to this structure, when the vibration generated by the feed drive of the stepping motor is not reduced even if the exciting current is reduced, the two-phase excitation method is changed to the 1-2 phase excitation method in which the stepping motor generates less vibration. Further stability is ensured during seek operation by switching.

According to a fifth aspect of the present invention, there is provided an optical disc device, wherein a condensing lens for condensing a laser beam on a surface of a track formed on a disc-shaped recording medium and recording information to generate a focal point, and the condensing lens. An optical pickup including an actuator for driving the laser beam onto the recording surface of the recording medium, a unit for detecting a deviation amount of a focal point of the laser beam with respect to the surface of the track, Means for controlling focus using the amount of focus deviation, means for detecting the amount of deviation of the focus from the center of the track, means for tracking control using the amount of focus deviation from the center of the track, The stepping motor for feeding and driving the optical pickup and the excitation method for the feeding drive for the stepping motor are two-phase excitation method. Selection means for selecting the 1-2 phase excitation method; calculation means for calculating the total number of steps for feeding and driving the stepping motor from this moving distance based on the current position and target position of the optical pickup; A means for applying an exciting current to the exciting coil of the motor and a controller for controlling the exciting current are provided, and the controlling means sends the optical pickup by the two-phase exciting method selected by the stepping motor by the selecting means. While driving, detects the amount of focus shift of the laser light,
When the amount of deviation exceeds a predetermined range, the interval between pulses for exciting the exciting coil is changed within a predetermined range.

According to this structure, the resonance caused by the vibration caused by the driving of the stepping motor and the vibration caused by the rotation of the optical disk can be prevented by changing the response frequency of the driving pulse of the stepping motor. −
The seek operation can be performed only by the two-phase excitation method that can increase the feed drive speed as compared with the two-phase excitation method, the moving speed in the seek operation can be improved, and the stability of the seek operation can be guaranteed.

An optical disk device according to a sixth aspect of the present invention is the optical disk device according to the fifth aspect of the present invention, in which storage means for storing an interval of exciting pulses during the feed driving of the stepping motor and feed driving of the stepping motor are provided. The control means is provided with a calculating means for calculating the position of the inside optical pickup from the position before the feeding drive and the number of steps advanced from that position, and a storing means for storing the position of the optical pickup calculated by the calculating means. , If the deviation amount of the focus of the laser light is detected, and the deviation amount exceeds a predetermined range, the pulse interval and the position of the optical pickup at this time are stored in the storage means, and again. When the optical pickup is driven to pass and passes through the stored position, the stored pulse interval is not set.

According to this structure, when the focus error signal corresponding to the shift amount of the focus of the laser beam exceeds the predetermined range during the seek operation, the pulse interval and the position of the optical pickup at that time are stored, and When passing through the memorized position in the next seek operation, by not setting the memorized pulse interval, resonance at a specific position can be prevented and the stability of the seek operation using the stepping motor is secured. To do.

An optical disk device according to a seventh aspect of the present invention is the optical disk device according to the fifth aspect, in which the control means has a predetermined range based on the stored pulse interval and centered on the pulse interval. Is provided, and when the optical pickup is driven again, the pulse interval within the predetermined range is not set.

With this configuration, it is possible to further reduce the possibility that the vibration generated by the stepping motor feed drive, the vibration caused by the rotation of the optical disk, or the like will resonate, and the stability of the seek operation can be secured.

An optical disk device according to a eighth aspect of the present invention is a condensing lens for condensing a laser beam on a surface of a track formed on a disc-shaped recording medium and recording information to generate a focal point, and the condensing lens. An optical pickup including an actuator for driving the laser beam onto the recording surface of the recording medium, a unit for detecting a deviation amount of a focal point of the laser beam with respect to the surface of the track, Focus control means using a focus shift amount, means for changing the servo gain of the focus control, means for detecting the shift amount of the focus from the center of the track, and focus control from the center of the track. A means for performing tracking control using the amount of deviation, a means for changing the servo gain of the tracking control, and a means for driving the optical pickup. Based on the stepping motor, the selection means for selecting the two-phase excitation method and the one-two-phase excitation method as the excitation method for the feed drive to the stepping motor, and the current position and target position of the optical pickup. Comprising: calculating means for calculating a total number of steps for driving the stepping motor from the moving distance; means for applying an exciting current to an exciting coil of the stepping motor; and controlling means for controlling the exciting current, While the stepping motor feeds and drives the optical pickup by the two-phase excitation method selected by the selecting means,
The focus shift amount of the laser light is detected, and when the shift amount exceeds a predetermined range, the servo gain is changed within a predetermined range.

According to this structure, by increasing the servo gain, it is possible to suppress the vibration exerted on the lens of the optical pickup at an early stage, and it is possible to increase the feed drive speed as compared with the 1-2 phase excitation method. The seek operation can be performed only by the phase excitation method, the moving speed in the seek operation is improved, and the stability of the seek operation is guaranteed.

An optical disk device according to a ninth aspect is the optical disk device according to the eighth aspect, wherein when the servo gain is changed, a storage means for storing the servo gain is provided to change the servo gain. When the optical pickup is driven and driven, the changed servo gain is stored in the storage means, and when the optical pickup is driven again, the stored servo gain is used to drive and drive.

According to this configuration, when the servo gain is changed during the seek operation, the servo gain is stored and the seek operation is performed using the stored servo gain from the next seek operation. The stability of the seek operation using the stepping motor is ensured.

An optical disk device according to a tenth aspect of the present invention is the optical disk device according to the eighth aspect, further comprising storage means for storing a servo gain before feeding drive of the optical pickup, and before feeding drive of the optical pickup. The servo gain is stored in the storage means, and is returned to the stored servo gain at the end of the feed drive of the optical pickup.

According to this structure, when the seek operation using the stepping motor is completed, the servo gain before the seek operation is restored, and the lens followability is too high in the processing other than the seek operation, so that the lens of the optical pickup is controlled. It is possible to prevent the actuator from being damaged due to excessive current flowing through the actuator.

An optical disk device showing an embodiment of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) An optical disk device according to Embodiment 1 of the present invention will be described.

FIG. 1 is a diagram for explaining the overall processing flow of the seek operation using the stepping motor in the optical disk device of the first embodiment, and FIG. 2 is a diagram showing the processing flow during the seek operation. FIG. 3 is a diagram showing drive pulses for operating the stepping motor.

Now, in the overall processing flow of the seek operation using the stepping motor of FIG. 1, first, the distance from the current address and the target address to the target position is obtained (step S101), and the stepping motor is calculated from the distance. The total number of feeding steps is calculated (step S102).
From the total number of steps, the number of steps of acceleration, constant speed, and deceleration is obtained (step S103).

Then, the seek operation using the two-phase excitation is started (step S104). During the seek operation, the D / A converter for controlling the two-phase excitation is set, the stepping motor is operated, and the optical pickup is moved by the calculated total number of steps.

During the seek operation, the processing shown in FIG. 2 is performed. First, a focus error signal (hereinafter referred to as an FE signal), which is the amount of focus deviation of the laser light with respect to the recording surface of the optical disc, is monitored, and when this FE signal exceeds a predetermined range (threshold value) (step S20).
1) The exciting current is within a predetermined range (step S202)
If the stepping motor is operating 2
The exciting current flowing through the stepping motor is changed by changing the D / A converter controlling the phase excitation as shown by the arrow in FIG. 3 (step S203).

Here, the predetermined range in which the exciting current can be changed in step S202 means that the load applied from the optical pickup to the stepping motor varies, and therefore the exciting current required for the stepping motor to move the pickup. Is guaranteed.

Basically, when the FE signal exceeds a predetermined range due to the vibration generated at the time of feed driving with two-phase excitation, the vibration from the stepping motor is reduced by decreasing the exciting current flowing in the stepping motor. Therefore, the FE signal can be suppressed within a predetermined range that does not adversely affect the focus control.

By doing so, the seek operation by the two-phase excitation becomes possible, the moving speed can be improved, and the stability of the seek operation can be guaranteed. Further, by storing the set value of the D / A converter that controls the two-phase excitation corresponding to the changed exciting current (step S204), the seek operation is performed using this value even in the next seek. By doing so, the vibration generated from the stepping motor from the start of the seek operation can be reduced, and the stability of the seek operation can be secured.

Further, in seek processing and other processing,
There is an optimum exciting current for each, and at the end of the seek operation,
When the exciting current is changed during the seek, the stability of the operation in the processing other than the seek operation can be secured by returning to the exciting current before the start of the seek.

If the FE signal exceeds the predetermined range even if the exciting current is lowered to the lower limit of the predetermined range in which the exciting current can be changed, switching to 1-2 phase excitation with less vibration from the stepping motor (step S205). ). By doing so, the stability of the seek operation using the stepping motor can be further ensured. (Second Embodiment) An optical disk device according to a second embodiment of the present invention will be described. It should be noted that the description of the flow of the entire processing of the same seek operation as in the first embodiment described above is omitted, and the flow of processing during the seek operation will be mainly described.

FIG. 4 is a diagram showing the flow of processing during the seek operation in the optical disk device of the second embodiment, and FIG. 5 is a diagram showing drive pulses for operating the stepping motor.

During the seek operation, the processing of the flow shown in FIG. 4 is performed. First, a focus error signal (hereinafter referred to as an FE signal), which is the amount of deviation of the focus of the laser light with respect to the recording surface of the optical disc, is monitored, and if the FE signal exceeds a predetermined range (step S301), stepping is performed. D that controls the two-phase excitation that operates the motor
The A / A converter changes the time per step of the arrow in FIG. 5 within a predetermined range (step S30
3) Change the response frequency of the drive pulse.

Here, the method of changing the response frequency of the drive pulse can be performed, for example, by changing the drive pulse interval from the Ta pulse interval shown in FIG. 5 to the Tb pulse interval. Further, the predetermined range in which the drive pulse interval can be changed is
The range is set to avoid a large change in response frequency that affects the driving of the stepping motor.

By doing so, when the FE signal exceeds the predetermined range due to the resonance caused by the vibration generated from the stepping motor when driving the stepping motor, the vibration caused when the optical disk rotates, etc. By changing the response frequency, the frequency of the vibration generated from the stepping motor changes, and the resonance frequency can be avoided. Therefore, the FE signal can be suppressed within a predetermined range, and the seek operation with two-phase excitation can be performed. It is possible to improve the moving speed and guarantee the stability of the seek operation.

When the FE signal exceeds the predetermined range, the current position of the optical pickup and the pulse interval for excitation change are stored (step S302). Here, the position of the optical pickup is equal to the current position at the start of the seek operation and F
It can be obtained from the number of steps the stepping motor has advanced to a position where the E signal exceeds a predetermined range. By doing so, when performing a seek operation in which the FE signal passes a position exceeding a predetermined range, the seek operation is performed so that the stored pulse interval of the excitation change is not set,
The stability of the seek operation using the stepping motor can be ensured more.

Further, based on the stored pulse interval of the excitation change, by not setting a predetermined range centered on this interval as the pulse interval of the excitation change, the possibility of resonance is further reduced, The stability of the seek operation using the stepping motor can be ensured more. (Third Embodiment) An optical disk device according to a third embodiment of the present invention will be described. It should be noted that the description of the flow relating to the overall processing of the same seek operation as in the first embodiment described above will be omitted, and the processing during the seek operation will be mainly described.

FIG. 6 is a diagram showing the flow of processing during the seek operation in the optical disk device of the third embodiment. During the seek operation, the processing of the flow shown in FIG. 6 is performed. First, a focus error signal (hereinafter referred to as an FE signal), which is the amount of focus deviation of the laser light with respect to the recording surface of the optical disc, is monitored. If the FE signal exceeds a predetermined range (step S401), the laser The focus servo gain for controlling the focus of light is increased within a predetermined range (step S402).

Here, when the focus servo gain is increased, if the servo gain is set too high, an excessive current may flow to the actuator that drives the lens of the optical pickup, which may damage the actuator. , Set an upper limit. This is a predetermined range of servo gain.

In the focus control, when the servo gain of the focus is increased, the followability of the lens is improved, so that the vibration exerted on the lens of the optical pickup can be suppressed in an early stage. A predetermined range can be suppressed early, a seek operation with two-phase excitation becomes possible, the moving speed can be improved, and the stability of the seek operation can be guaranteed.

When the focus servo gain is changed during the seek operation, the set value of the servo gain is stored (step S403), and the servo gain stored from the start of the seek is calculated from the next seek operation. By performing the seek operation using the stepping motor, the stability of the seek operation using the stepping motor can be ensured.

At the end of the seek, the focus servo gain before the seek is started is returned (step S40).
5) In processing other than seek, the followability of the lens is too high, so that current may flow too much to the actuator that controls the lens of the optical pickup, and the actuator may be damaged. It can prevent damage.

[0062]

As described above, according to the present invention, in the seek operation by the stepping motor, the drive pulse of the stepping motor is controlled or the focus servo gain is changed while monitoring the focus error signal. Further, it is possible to suppress the vibration generated due to the driving of the stepping motor and also suppress the vibration applied to the lens of the optical pickup.

Therefore, during the seek operation by the stepping motor, the seek operation can be performed only by the two-phase excitation method, which can increase the feed drive speed as compared with the 1-2 phase excitation method, and the moving speed of the optical pickup in the seek operation. And the stability of seek operation can be guaranteed.

[Brief description of drawings]

FIG. 1 is a flowchart showing seek processing of an optical disk device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a process during a stepping motor feed drive in a seek process of the optical disk device according to the first embodiment.

FIG. 3 is a waveform diagram showing drive pulses of a stepping motor in the optical disk device of the first embodiment.

FIG. 4 is a flowchart showing a process during a stepping motor feed drive in a seek process of the optical disk device according to the second embodiment of the present invention.

FIG. 5 is a waveform diagram showing drive pulses of a stepping motor in the optical disc device according to the second embodiment.

FIG. 6 is a flowchart showing a process during a stepping motor feed drive in the seek process of the optical disk device according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing the configuration of an optical disc device that has been conventionally used.

FIG. 8 is a timing chart showing a two-phase excitation drive of a two-phase stepping motor in an optical disk device which has been conventionally used.

FIG. 9 is a timing chart showing 1-2 phase excitation drive of a 2-phase stepping motor in an optical disk device which has been conventionally used.

FIG. 10 is a cross-sectional view of a two-phase stepping motor used in a conventional optical disk device as viewed from the rotation axis direction.

FIG. 11 is a flowchart showing a seek process of a conventional optical disc device.

FIG. 12 is an explanatory diagram of the relationship between the number of steps and the drive pulse response frequency in the seek processing of the optical disc device of the conventional example.

FIG. 13 is an explanatory diagram showing the relationship between the moving time of the optical pickup and the response frequency of the drive pulse in the seek processing of the optical disc device of the conventional example.

[Explanation of symbols]

11 pickups 12 lead screw 13 Stepping motor 14 discs 15 A-phase setting D / A converter 16 B-phase setting D / A converter 17 Stepping motor drive driver 18 CPU 19 Focus servo and tracking servo circuit 20 Focus and tracking driver 21 Stepping motor rotor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiyuki Fujii             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. F term (reference) 5D117 AA02 BB06 CC06 FF03 FF07                       FF27 JJ02 JJ06

Claims (10)

[Claims] 1. A condensing lens for condensing a laser beam onto a surface of a track formed on a disc-shaped recording medium and having information recorded thereon to generate a focal point, and an actuator for driving the condensing lens, An optical pickup that irradiates a recording surface of the recording medium with a laser beam, a unit that detects the amount of defocus of the laser beam with respect to the surface of the track, and a focus using the amount of defocus of the surface of the track. Control means, means for detecting the amount of deviation of the focus from the center of the track, means for tracking control using the amount of deviation of the focus from the center of the track, and a stepping motor for feeding and driving the optical pickup. And selecting an excitation method for the feed drive for the stepping motor, a two-phase excitation method or a 1-2-phase excitation method. Means, calculating means for calculating the total number of steps for driving the stepping motor from the moving distance based on the current position and the target position of the optical pickup, and means for applying an exciting current to an exciting coil of the stepping motor. And a control means for controlling the exciting current, the focus of the laser light while the stepping motor drives and drives the optical pickup by the two-phase excitation method selected by the selecting means. Is detected, and when the amount of deviation exceeds a predetermined range, the exciting current to the stepping motor is changed within a predetermined range. 2. The optical disk device according to claim 1, wherein when the exciting current is changed, a storage means for storing the changed exciting current is provided, and the control means controls the exciting current to the stepping motor. An optical disk device characterized in that, when changed, the changed exciting current is stored in the storage means, and when the optical pickup is again fed and driven, it is driven by the stored exciting current. 3. The optical disk device according to claim 1, further comprising a storage unit that stores an exciting current before the optical pickup is driven to drive, and the control unit controls the exciting current before the optical pickup is driven to drive. An optical disk device, which is stored in the storage means and is configured to return to the stored exciting current when the drive driving of the optical pickup is completed. 4. The optical disk device according to claim 1, wherein the control means, even if the exciting current is lowered to a lower limit of the exciting current within a predetermined range of the exciting current, from the center of the track of the laser beam. The optical disc device is configured such that when the amount of focus deviation of the above exceeds a predetermined range, the excitation method is switched from the two-phase excitation method to the one-two-phase excitation method by the selection means. 5. A condensing lens for condensing a laser beam on a surface of a track formed on a disc-shaped recording medium and having information recorded thereon to generate a focal point, and an actuator for driving the condensing lens, An optical pickup that irradiates a recording surface of the recording medium with a laser beam, a unit that detects the amount of defocus of the laser beam with respect to the surface of the track, and a focus using the amount of defocus of the surface of the track. Control means, means for detecting the amount of deviation of the focus from the center of the track, means for tracking control using the amount of deviation of the focus from the center of the track, and a stepping motor for feeding and driving the optical pickup. And selecting an excitation method for the feed drive for the stepping motor, a two-phase excitation method or a 1-2-phase excitation method. Means, calculating means for calculating the total number of steps for driving the stepping motor from the moving distance based on the current position and the target position of the optical pickup, and means for applying an exciting current to an exciting coil of the stepping motor. And a control means for controlling the exciting current, the focus of the laser light while the stepping motor drives and drives the optical pickup by the two-phase excitation method selected by the selecting means. Is detected, and when the deviation exceeds a predetermined range, the interval of pulses for exciting the exciting coil is changed within a predetermined range. 6. The optical disk device according to claim 5, wherein a storage unit that stores an interval of an excitation pulse during feed driving of the stepping motor and a position of an optical pickup during feed driving of the stepping motor are provided. Provided is a calculating means for calculating from the position before the feeding drive and the number of steps advanced from that position, and a storing means for storing the position of the optical pickup calculated by the calculating means, and the controlling means controls the focus of the laser beam. When the deviation amount is detected and the deviation amount exceeds a predetermined range, the pulse interval and the position of the optical pickup at this time are stored in the storage means, and when the optical pickup is driven again, the deviation is detected. An optical disk device, characterized in that the stored pulse interval is not set when passing through a stored position. 7. The optical disk device according to claim 5, wherein the control means is provided with a predetermined range centered on the stored pulse interval and the optical pickup is sent again. An optical disk device characterized in that, when being driven, the pulse interval within the predetermined range is not set. 8. A condensing lens for condensing a laser beam on a surface of a track formed on a disc-shaped recording medium and having information recorded thereon to generate a focal point, and an actuator for driving the condensing lens, An optical pickup that irradiates a recording surface of the recording medium with a laser beam, a unit that detects the amount of defocus of the laser beam with respect to the surface of the track, and a focus using the amount of defocus of the surface of the track. Tracking control using means for controlling, means for changing the servo gain of the focus control, means for detecting a deviation amount of the focus from the center of the track, and deviation amount of the focus from the center of the track. Means, means for changing the servo gain of the tracking control, a stepping motor for feeding and driving the optical pickup, Based on the selection means for selecting the two-phase excitation method and the one-two-phase excitation method as the excitation method for the feeding drive to the stepping motor, and based on the current position and the target position of the optical pickup, from this moving distance The stepping motor is provided with a calculating means for calculating a total number of steps for feeding and driving the stepping motor, a means for applying an exciting current to an exciting coil of the stepping motor, and a controlling means for controlling the exciting current, wherein the stepping motor has the selection. While the optical pickup is being driven by the two-phase excitation method selected by the means, the shift amount of the focus of the laser light is detected, and when the shift amount exceeds a predetermined range, the servo gain is set to a predetermined range. An optical disk device characterized in that the optical disk device is configured to be changed. 9. The optical disk device according to claim 8, wherein when the servo gain is changed, a storage means for storing the servo gain is provided, and the servo gain is changed to drive the optical pickup. An optical disk device, wherein the changed servo gain is stored in the storage means, and when the optical pickup is driven again, the stored servo gain is used to drive the optical pickup. 10. The optical disk device according to claim 8, further comprising a storage unit that stores a servo gain before the feed drive of the optical pickup, and the servo gain is stored in the storage unit before the feed drive of the optical pickup. Remember
An optical disk device, which is configured to return to the stored servo gain when the driving of the optical pickup is completed.