JPH10334624A - Optical-information-record reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the vibration and heating when a stepping motor is driven, and to move an optical pickup stably when the stepping motor is used for the movement of the optical pickup. SOLUTION: In this device, a pulse-rate pattern variable means 16 changes the frequency of the driving pulses of a stepping motor (pulse rate) and outputs the pulses. A pulse-rate measuring means 13 measures the changing rate of the pulse rate. A driving-voltage variable means 14 decreases the amplitude of the pulse-shaped voltage for driving the stepping motor in correspondence with the pulse rate and the rate of change of the pulse rate. In this way, the amplitude of the driving voltage can be lowered at the part where the pulse rate is low and the changing rate of the pulse rate (acceleration) is low. The generation of the surplus torque of the stepping motor is decreased, and the vibration and heating of the motor by the surplus torque are suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus used for a CD-ROM drive or the like.

[0002]

2. Description of the Related Art In recent years, an optical information recording / reproducing apparatus has been required to have high-speed access performance for sending an optical pickup to a target position on a disk in a short time. An optical information recording / reproducing apparatus using a stepping motor has been commercialized as a traverse motor for sending an optical pickup. Since the stepping motor rotates at a constant basic step angle with respect to the drive pulse, it is easy to open-control the moving amount of the optical pickup feed, and the pickup feed mechanism can be simplified since no position detecting means is required. Further, since the stepping motor rotates in synchronization with the frequency (pulse rate) of the driving pulse, speed control can be easily realized.

Hereinafter, a conventional optical information recording / reproducing apparatus will be described with reference to the drawings. FIG. 8 is a block diagram showing a configuration of a conventional optical information recording / reproducing apparatus. FIG. 9 shows a conventional drive pulse frequency change waveform (pulse change) when the stepping motor is continuously fed in order to send the optical pickup 3 at high speed. FIG. 6 is a diagram showing a temporal relationship among a rate pattern), generated torque, and required torque.

In FIG. 8, reference numeral 1 denotes a disk having a spiral information track, 2 denotes a spindle motor for rotating the disk 1, 3 denotes an optical pickup, and 4 denotes an objective lens mounted on the optical pickup 3.

[0005] The objective lens 4 is provided so as to be electromagnetically movable in the vertical and horizontal directions by a focus actuator and a tracking actuator (not shown) built in the optical pickup 3 respectively. Reference numeral 5 denotes a focus servo means, which drives the focus actuator based on a focus error signal indicating the amount of displacement of the objective lens 4 from the disk 1 so that the objective lens 4 keeps a constant distance from the disk 1. Reference numeral 6 denotes a tracking servo means, and the disk 1 of the objective lens 4
The tracking actuator is driven so that the objective lens 4 follows an arbitrary track on the disk 1 based on a tracking error signal which is an amount of displacement from an upper track center.

Reference numeral 7 denotes a stepping motor for moving the optical pickup 3, reference numeral 8 denotes a stepping motor driving means for applying a pulsed driving voltage to the coil of the stepping motor 7 in accordance with the input pulse, and reference numeral 9 denotes the optical pickup 3. Optical pickup position detecting means 10 for detecting the current position of the optical pickup 3 from the address information included in the read data, and an optical pickup 3 based on the current position detected by the optical pickup position detecting means 9 and a target address inputted from outside. A pulse number calculating means 11 for calculating the number of stepping motor driving pulses necessary for moving the stepping motor, a pulse frequency input to the stepping motor driving means 8 based on the number of pulses calculated by the pulse number calculating means 10 changes at a constant frequency ( Pulse output with pulse rate pattern) Rate pattern creating means, 12 is a lead screw for transmitting the torque of the stepping motor 7 in the optical pickup 3 with the optical pickup 3 for holding movably in the radial direction of the disk 1.

The operation of the conventional optical information recording / reproducing apparatus having the above-described configuration for transmitting the optical pickup 3 at a high speed will be described below. In order to read information from the disk 1 by the optical pickup 3, the objective lens 4 is shown by the focus servo means 5 so that it is always in focus on the disk 1 and the tracking servo means 6 so that it always follows the tracks of the disk 1. Not controlled by an electromagnetic actuator. In order to access an arbitrary track, first, the number of pulses required for moving from the current optical pickup position detected by the optical pickup position detecting means 9 to the target is calculated by the pulse number calculating means 10.

Next, while the operation of the tracking servo means 6 is stopped, the pulse rate pattern creating means 11
Then, the stepping motor 7 is driven by the stepping motor driving means 8 at a pulse rate as shown in FIG. After the movement, the tracking servo means 6 is operated again to record and reproduce information. In FIG. 9A, the pulse rate is output as follows by the pulse rate creating means 11 constituted by a microcomputer or the like. That is, the pulse rate is set at a frequency at which the stepping motor 7 can be started from a stop state without step-out (that is, the stepping motor 7 loses synchronization with the input pulse rate and does not rotate normally). The output is started, and thereafter, the pulse rate is increased at a constant pulse rate change rate up to a predetermined frequency, and the pulse rate is reduced so as to be symmetrical with the pulse rate increase, and the output of the pulse is stopped.

On the other hand, there is known a control method called micro-step drive in which a basic step angle of a stepping motor is divided into n (n is an integer of 2 or more) and a positioning resolution of the stepping motor is multiplied by n. Hereinafter, a description will be given of a stepping motor driving unit employing conventional micro-step driving.

FIG. 10 is a block diagram schematically showing the internal structure of a general stepping motor. In FIG. 10, 10a represents a voltage applied to the A-phase coil, and 10b represents a voltage applied to the B-phase coil. The rotor 10c has one or more pairs of magnetic poles N and S in the rotation direction. The number of magnetic poles differs depending on the type of the stepping motor. Point P on rotor
Starts rotating when the voltage 10a applied to the A-phase coil and the voltage 10b applied to the B-phase coil change,
It stops at the point where the balance between the magnetic force generated from the coil and the friction load is stabilized, that is, at the mechanical stability point. Points 10X and 10Z represent two points adjacent to each other among several mechanical stable points existing in the rotor 10c.
The rotation angle from the point 10X to the point 10Z is the basic step angle of the stepping motor. Point 10Y represents one of several mechanically unstable points existing between point 10X and point 10Z. In order to rotate the stepping motor slightly, it is necessary to stop the rotor 10c at a mechanically unstable point between the basic step angles as shown by a point 10Y.

Next, phase A and phase B of the stepping motor
The voltage applied to each coil of the phase will be described. FIG. 11 is a waveform diagram showing a conventional stepping motor drive voltage. The waveform diagram shown in FIG. 11 shows a control method called a 1-2 phase excitation method in which a basic step angle of a stepping motor is divided into two and rotated by a half step angle. There is also known a control method in which the basic step angle of the stepping motor is divided into n parts (n is an integer of 2 or more) more finely than the ス テ ッ プ step angle, and the stepping motor is rotated by 1 / n step angles. For simplicity, among the control methods for driving the stepping motor by dividing the basic step angle into n steps, the stepping motor drive voltage in the case where the stepping motor is driven by the smallest number of divisions will be described.

In FIG. 11, reference numeral 11a denotes a drive voltage waveform representing the voltage applied to the A-phase coil of the stepping motor on the time axis. 11b is a drive voltage waveform representing the voltage applied to the B-phase coil of the stepping motor on the time axis. However, when the state of the stepping motor drive voltage applied to each of the A-phase and B-phase coils in FIG. 11 is 11X, the point P in FIG. 10 is at the 10X position. Similarly, in the state 11Y and the state 11Z, the point 10Y,
It is assumed that it is at a rotation position of 10Z. The voltage waveform when the stepping motor is rotated in the forward direction changes from left to right in FIG. The voltage waveform when the stepping motor is rotated in the reverse direction changes from right to left in FIG.

In FIG. 11, the voltage state changes from 11X to 1
When changing to 1Z, there is an intermediate state 11Y. In state 11Y, only the A-phase coil of FIG.
Phase coils are not energized. Therefore, it is possible to move to the point 10Y located between the point 10X and the point 10Z in FIG. 10, and it is possible to move the stepping motor to a position at a half step angle of the basic step angle. By driving the stepping motor by dividing the basic step angle by n, the stepping motor can be rotated by a small amount. When used for pickup feed of a disk device, the pickup can be moved by a small amount in the radial direction of the disk during recording and reproduction of the disk or at the time of accessing an arbitrary track.

[0014]

However, the above-mentioned conventional configuration has the following problems at the time of accessing an arbitrary track.

The first problem will be described. As shown in FIG. 11, when the amplitude of the drive voltage of the stepping motor is constant, excess torque is generated at the time of low pulse rate driving as shown in FIG. 9B. When excess torque is generated, the stepping motor rotates while vibrating. The vibration is transmitted to the optical pickup via the lead screw 12, and the control of the objective lens 4 becomes unstable. In the worst case, a focus jump or a tracking loss is caused.

Heat generation has also been a problem due to the excess current flowing through the motor coil, which is a cause of the excess torque.

The mechanism by which the generation of surplus torque causes vibration will be described in detail below.

FIG. 12 is a waveform diagram showing the voltage applied to the A-phase and B-phase coils of the stepping motor and the time change of the displacement of the rotation angle of the stepping motor. FIG.
In (a), 12a1, 12a2, and 12a3 represent voltages applied to the A-phase coil. In FIG. 12B, 1
2b1, 12b2, and 12b3 represent voltages applied to the B-phase coil. In FIG. 12C, 12c1 represents the rotational angular displacement of the stepping motor when 12a1 and 12b1 are applied to the A-phase and B-phase coils, respectively.
Similarly, 12c2 and 12c3 are waveform diagrams showing rotational angular displacements of the stepping motor when 12a2 and 12b2 and 12a3 and 12b3 are applied to the A-phase and B-phase coils, respectively.

In the drawing, 12X, 12Z, and 12W represent combinations of the voltage applied to the coil of the stepping motor and the rotational displacement of the stepping motor, respectively. In FIGS. When the voltage is 12X, the rotational displacement of the stepping motor is 12 in FIG.
The position becomes the X position. Similarly, in FIGS. 12A and 12B, the state of the voltage applied to the coil of the stepping motor is 1 respectively.
In the state of 2Z, 12W, the rotational displacement of the stepping motor is at the position of 12Z, 12W in FIG. 12 (c). Further, in FIGS.
Since the time of X, 12Z and 12W is the pulse period, the reciprocal of this is the pulse rate.

When the stepping motor is driven, FIG.
As shown in (a) and (b), the difference in the magnitude of the voltage applied to the A-phase and B-phase coils, that is, the difference in the magnitude of the generated torque causes a difference in the rotation settling to the target stepping motor rotation angle. . A-phase and B-phase coil voltage is 1
In the case of 2a1 and 12b1, the rotation angle of the stepping motor rotates while greatly vibrating as in 12c1.
This is because an excessive torque is generated with respect to the pulse rate, that is, the motor rotation speed.

Conversely, if the generated torque is too small (the A-phase and B-phase coil voltages are 12a3 and 12b3, respectively), the stepping motor rotation angle becomes the next coil voltage before being displaced to the target rotation angle as indicated by 12c3. Switch to
Eventually, the motor rotation speed will not be synchronized with the drive pulse, and in the worst case, the motor will not rotate, causing a step-out phenomenon. On the other hand, the optimal torque for the pulse rate (the A-phase and B-phase coil voltages are 12a2, 1
In the case of 2b2), the rotation angle of the stepping motor is 12
As shown by c2, the motor is switched to the next coil voltage around the point where the motor is almost displaced to the target rotation angle, so that the motor rotates smoothly.

As shown in FIG. 11, when the amplitude of the driving voltage of the stepping motor is constant, excess torque is generated at the time of low pulse rate driving as shown in FIG. 9B.

When excess torque is generated, 12c in FIG.
As shown in FIG. 1, the stepping motor rotates while vibrating. The vibration is transmitted to the optical pickup via the lead screw 12, and the control of the objective lens 4 becomes unstable. In the worst case, a focus jump or a tracking loss is caused. Heat generation has also been a problem due to excess current flowing through the motor coil, which is a cause of excess torque.

The second problem is that, by increasing the positioning resolution of the stepping motor by n times, a torque variation occurs when the stepping motor driving voltage shown in FIG. In the excitation state 11X, 11Z to the basic step angle in FIG.
A constant voltage is applied to both the B phase, but in the excitation state 11Y to the mechanical instability point, a constant voltage is applied only to the A phase,
The B-phase voltage is zero. As a result, a relatively large torque is generated at the basic step angle, but the torque is smaller at the mechanical instability point. In other words, there is a difference between the basic step angle and the magnitude of the generated torque at other mechanical instability points, so the vibration of the stepping motor during the movement of the optical pickup is further increased, and in the worst case, the stepping motor loses synchronism. cause. Further, when the optical pickup 3 is moved to a mechanically unstable point, only one phase is driven when the optical pickup 3 is stopped.
There is also a problem that the accuracy of the stop position is deteriorated.

In view of the above problems, the present invention suppresses the vibration and heat generation of the motor and enables the optical pickup to move at high speed by effectively controlling the torque generated by the motor when the stepping motor is continuously fed at high speed. And an optical information recording / reproducing apparatus. In order to further improve the positioning performance, an optical information recording / reproducing apparatus capable of moving the optical pickup stably and at high speed even when the stepping motor is driven by dividing the basic step angle by n (n is an integer of 2 or more). To provide.

[0026]

In order to solve the above-mentioned problems, an optical information recording / reproducing apparatus according to the present invention comprises means for creating a temporal change pattern of frequency, and means for making the temporal change pattern variable. The means for varying the frequency of the pulse signal is provided, and as the frequency of the pulse signal increases,
The frequency change rate is configured to be small. Further, a means for varying the amplitude of the pulse-shaped drive voltage applied to the stepping motor is provided, and the amplitude of the drive voltage is increased as the frequency of the pulse signal increases. A pulse rate measuring means for measuring a frequency of the pulse signal; a track speed detecting means for detecting a moving speed of an objective lens mounted on the optical pickup means based on a tracking error signal output from the optical pickup means; Lens vibration detecting means for detecting the amount of vibration of the objective lens based on the output of the rate measuring means and the output of the track speed detecting means, and providing a pulse-like drive voltage to the stepping motor based on the output of the lens vibration detecting means. It is configured to apply.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 Hereinafter, an embodiment 1 of the present invention will be described with reference to the drawings. The same reference numerals are given to the same components as in the conventional example. FIG. 1 is a block diagram showing a configuration of an optical information reproducing apparatus according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a pulse rate, generated torque and required torque, and time of drive voltage in the first embodiment of the present invention. FIG.

In FIG. 1, 1 is a disk having a spiral information track, 2 is a spindle motor for rotating the disk 1, 3 is an optical pickup, 4 is an objective lens mounted in the optical pickup 3, and 5 is a focus. Actuator means for driving the focus actuator based on a focus error signal indicating the amount of displacement of the objective lens 4 from the disk 1 so that the objective lens 4 keeps a constant distance from the disk 1. Reference numeral 6 denotes a tracking servo means, which controls the tracking actuator so that the objective lens 4 follows an arbitrary track on the disk 1 based on a tracking error signal indicating the amount of displacement of the objective lens 4 from the track center on the disk 1. Drive. 7 is a stepping motor for moving the optical pickup 3; 8 is a stepping motor driving means for applying a pulsed driving voltage to the coil of the stepping motor 7 according to the input pulse; 9 is read by the optical pickup 3 The optical pickup position detecting means 10 for detecting the current position of the optical pickup 3 from the address information included in the read data moves the optical pick 3 from the current position detected by the position detecting means 9 and a target address inputted from outside. Number calculating means for calculating the number of stepping motor driving pulses required for
1 is a pulse rate pattern creating means for outputting a two-phase signal input to the stepping motor driving means 8 at a constant frequency change (pulse rate pattern) based on the number of pulses calculated by the pulse number calculating means 10, and 13 is a pulse rate pattern A pulse rate measuring means including a timer or the like for measuring the pulse rate of the creating means 11;
Reference numeral 15 denotes a pulse rate change rate measuring means constituted by a timer or the like for measuring a pulse rate change rate of the pulse rate pattern creating means 11, and 14 denotes a measured value of the pulse rate measuring means 13 and a pulse rate change rate measuring means 15.
A driving voltage varying means 16 for changing the driving voltage of the stepping motor driving means 8 based on the measured value of the stepping motor driving means 16;
Pulse rate pattern creating means 11 based on the measured value of 5
The pulse rate changing means 12 for changing the pulse rate change rate of the optical disk 1 is a lead screw for holding the optical pickup 3 movably in the radial direction of the disk 1 and transmitting the torque of the stepping motor 7 to the optical pickup 3.

In FIG. 2, (a) is a pulse rate,
(B) shows the torque generated by the stepping motor and the torque required for driving at the pulse rate of (a), and (c) shows the amplitude of the driving voltage. The output of the pulse rate (a) is started at a frequency at which the stepping motor 7 can be started from the stopped state without stepping out.

The operation of the optical information recording / reproducing apparatus of the present invention configured as described above will be described below. In order to read information from the disk 1 by the optical pickup 3, the objective lens 4 is controlled by the focus servo means 5 so that the objective lens 4 is always focused on the disk 1, and the tracking servo means 6 is configured to always follow the track of the disk 1. It is controlled by an electromagnetic actuator.

Next, to access an arbitrary track,
First, in order to determine the current position of the optical pickup 3,
Data including address information on the disk 1 is read by the optical pickup 3. From the address information, the current optical pickup position is detected by the optical pickup position detecting means 9, and the number of pulses required for moving from the detected current optical pickup position to the target track is calculated by the pulse number calculating means 10. Next, the operation of the tracking servo means 6 is stopped, and the stepping motor driving means 8 is driven by the pulse rate pattern creating means 11 constituted by a microcomputer or the like at a pulse rate as shown in FIG.
Is used to drive the stepping motor 7 to move the optical pickup 3. At this time, the rate of change of the pulse rate is switched at the timing shown in FIG. 2A, and the driving voltage of the stepping motor driving means 8 is changed to the level shown in FIG.
Variable as shown in (c). After the optical pickup 3 is moved, the tracking servo means 6 is operated again to record and reproduce information.

The frequency (pulse rate) of the pulse output from the pulse rate pattern creating means 11 and the rate of change of the frequency (pulse rate change rate) are measured by the pulse rate measuring means 11 and the pulse rate change rate measuring means 13, respectively. It measures and inputs the measurement result to the pulse rate pattern variable means 16. Pulse rate pattern variable means 1
Reference numeral 6 denotes a microcomputer or the like, and stores in advance a relationship between a pulse rate calculated from a torque characteristic of a motor to be used and a friction load of a mechanism and a pulse rate change rate (motor acceleration) in a memory or the like. In accordance with this intercourse,
By switching the pulse rate change rate of the pulse rate pattern creating means 11 by the pulse rate pattern changing means 16 during the movement of the optical pickup, the pulse rate as shown in FIG.
Since most of the generated torque is used as the acceleration torque, the generation of the surplus torque can be suppressed. Each output of the pulse rate measuring means 13 and the pulse rate change rate measuring means 15 is also input to the driving voltage varying means 14, and the driving voltage varying means 14 is constituted by a microcomputer, a transistor, a resistor, etc. 2 (c), the voltage amplitude applied to the coil of the stepping motor 7 of the stepping motor driving means 8 is controlled so that
Control as follows.

With the above configuration, as shown in FIG. 2 (a), by switching the pulse rate change rate, it is possible to accelerate at the maximum torque during acceleration and to suppress vibration by suppressing excess torque. In addition, during deceleration, the drive voltage is gradually reduced to minimize the generation of excess torque of the stepping motor 7 as shown in FIG. 2B, and the optimal driving force for the optical pickup 3 via the lead screw 12 is obtained. Optical pickup 3 without vibrating the lens.
Can be moved at high speed.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described.
The embodiment will be described with reference to the drawings. The same reference numerals are given to the same components as in the conventional example. FIG. 3 is a block diagram showing a configuration of an optical information reproducing apparatus according to Embodiment 2 of the present invention, and only a portion different from the conventional apparatus will be described. 13 is a pulse rate pattern creating means 11
Pulse rate measuring means for measuring the pulse rate of
Is a pulse rate change rate measuring means for measuring the change rate of the pulse rate of the pulse rate pattern creating means 11, and 17 is a stepping motor driving means 8 according to the measured values of the pulse rate measuring means 13 and the pulse rate change rate measuring means 15.
Is a drive voltage change rate varying means for making the change rate of the drive voltage variable. FIG. 4 is a waveform diagram showing, on a time axis, voltages applied to the A-phase and B-phase coils of the stepping motor 8 according to the second embodiment of the present invention.

The operation of the optical information recording / reproducing apparatus of the present invention configured as described above will be described with reference to FIG. What is different from the first embodiment is that the drive voltage amplitude of the stepping motor 7 is changed according to the measured values of the pulse rate measuring means 13 and the pulse rate change rate measuring means 15 instead of the drive voltage amplitude of the stepping motor 7. And the rate of change (K) at the fall. Instead of instantaneously changing the drive voltage of the stepping motor in a stepwise manner, as shown in FIG. 4, where torque is not required during low-speed rotation, the rate of change (K) is reduced and the drive voltage is reduced over time. By gradually changing it in proportion, the change of the starting torque generated in the stepping motor is suppressed to a small value to suppress the vibration of the motor,
When torque is required, such as during acceleration or high-speed movement, the drive voltage is changed instantaneously by increasing the rate of change of the drive voltage of the stepping motor 7 to generate a large starting torque. With this configuration, it is possible to move the optical pickup 3 stably and at high speed.

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described.
The embodiment will be described with reference to the drawings. The same reference numerals are given to the same components as in the conventional example. FIG. 5 is a block diagram showing the configuration of an optical information reproducing apparatus according to the third embodiment of the present invention, and only the parts different from the conventional apparatus will be described. 13 is a pulse rate measuring means for measuring the pulse rate of the pulse rate pattern creating means 11. Reference numeral 18 denotes a track speed detecting means for measuring the speed at which the objective lens 4 crosses the track in the tracking error signal which detects the displacement of the objective lens 4 from the track based on the output of the optical pickup 3. 19
Are pulse rate measuring means 13 and track speed detecting means 1
The lens vibration detecting means 14 detects the amount of vibration of the objective lens 4 with respect to the optical pickup 3 based on the difference from the output value of the lens 8. The driving voltage of the stepping motor driving means 8 is determined based on the detected amount of the lens vibration detecting means. This is a drive voltage variable unit that changes the amplitude.

The operation of the optical information recording / reproducing apparatus of the present invention configured as described above will be described with reference to FIG.

The difference from the first embodiment is that the amplitude of the drive voltage of the stepping motor 7 is not changed by the pulse rate and the pulse rate change rate, but is changed according to the lens vibration amount detected by the lens vibration detecting means 19. This is to vary the amplitude of the drive voltage of the stepping motor 7.

As described in the description of the first embodiment,
When the optical pickup 3 is moved by driving the stepping motor 7, vibrations are generated in the stepping motor 7 substantially in accordance with the torque characteristics of the motor and the load characteristics of the mechanism. The vibration is transmitted to the objective lens 4 and moves with the optical pickup 3 while vibrating.

Here, the moving speed of the objective lens 4 is regarded as equivalent to the rotation speed of the stepping motor 7, so that the objective lens 4 detected by the track speed detecting means 18 is obtained.
Is compared with the pulse rate detected by the pulse rate measuring means 13 (that is, the target speed of the stepping motor 7), the vibration amount of the stepping motor 7 is obtained as the vibration amount of the objective lens 4. If the detected amount of vibration is positive (track speed> pulse rate), it indicates that the optical pickup 3 has advanced too far with respect to the pulse rate, that is, that the torque is excessive, so that the drive voltage of the stepping motor 7 is Decrease the amplitude of
On the other hand, if the detected amount of vibration is negative (track speed <pulse rate), it indicates that the optical pickup 3 is behind the pulse rate, that is, the torque is insufficient. Variable so as to increase the amplitude of the drive voltage. With this configuration, even if the mechanical friction load or the like fluctuates with time, the stepping motor 7 generates an optimal torque, transmits the driving force to the optical pickup 3 via the lead screw 12, and The pickup 3 can be moved stably.

(Embodiment 4) Hereinafter, Embodiment 4 of the present invention will be described.
The embodiment will be described with reference to the drawings. The same components as those of the conventional example and the third embodiment are denoted by the same reference numerals. FIG. 6 is a block diagram showing a configuration of an optical information reproducing apparatus according to the fourth embodiment of the present invention, and only parts having a different configuration from the optical information reproducing apparatus according to the third embodiment will be described. Reference numeral 20 denotes switch means for switching an input to a tracking actuator (not shown) to either the output of the tracking servo means 6 or the output of the lens vibration detecting means 19, and is constituted by electronic circuit means such as a transistor.

The operation of the optical information recording / reproducing apparatus of the present invention configured as described above will be described with reference to FIG. What is different from the conventional example is that when the optical pickup 3 is moved by driving the stepping motor 7,
Instead of opening the tracking servo means 6, the measurement value of the lens vibration detecting means 19 is applied to the tracking actuator.

As described in the first embodiment, when the optical pickup 3 is moved by driving the stepping motor 7, the stepping motor 7 generates vibration substantially corresponding to the torque characteristics of the motor and the load characteristics of the mechanism. Then, the vibration is transmitted to the objective lens 4 in the optical pickup 3 and moves with the optical pickup 3 while vibrating.

Here, by subtracting the pulse rate (ie, the target speed of the stepping motor 7) detected by the pulse rate measuring means 13 from the moving speed of the objective lens 4 detected by the track speed detecting means 18, The speed error with respect to the target rotation speed of the stepping motor 7 is obtained. Since the stepping motor 7 rotates in synchronism with the pulse rate, it is detected by the lens vibration detecting means 19 by assuming that the pulse rate, that is, the rotation speed of the stepping motor 7 and the moving speed of the optical pickup 3 are equivalently equivalent. The velocity error is considered to be the relative velocity of the objective lens 4 with respect to the optical pickup 3, that is, the amount of vibration with respect to the optical pickup 3. Therefore, the detection value of the lens vibration detection means 19 is fed back to the tracking actuator in the optical pickup 3 by the switch means 20 so that the relative speed of the lens becomes zero.

With this configuration, the vibration of the objective lens 4 with respect to the optical pickup 3 can be suppressed even while the optical pickup 3 is moving, so that the objective lens 4
And the displacement of the objective lens 4 after the movement of the optical pickup 3 can be reduced to zero, so that the error from the target track after the movement of the optical pickup 3 is reduced, and the remaining distance to the target track is reduced. The time required for movement can be reduced, and access performance can be improved.

Embodiment 5 Hereinafter, Embodiment 5 of the present invention will be described.
Will be described with reference to the drawings. FIG. 7 is a waveform diagram showing, on a time axis, the voltage applied to the A-phase and B-phase coils of the stepping motor and the torque generated by the stepping motor when the optical pickup is moved in the fifth embodiment.

FIG. 7A is a waveform diagram when the stepping motor is continuously fed in the forward direction from the basic step angle.
In FIG. 7A, reference numerals 7a1, 7b1, and 7c1 denote a voltage applied to the A-phase coil, a voltage applied to the B-phase coil, and a torque generated by the stepping motor, respectively. FIG. 7 (b)
FIG. 7 is a waveform diagram when a stepping motor is continuously fed in a forward direction from a mechanically unstable point other than the basic step angle. In FIG. 7B, 7a2, 7b2, and 7c2 are A
These are the voltage applied to the phase coil, the voltage applied to the B-phase coil, and the torque generated by the stepping motor. FIG. 7C is a waveform diagram when the stepping motor is continuously fed in the forward direction up to the basic step angle. In FIG. 7C, 7a
Reference numerals 3, 7b3, and 7c3 denote a voltage applied to the A-phase coil, a voltage applied to the B-phase coil, and a torque generated by the stepping motor, respectively. FIG. 7D is a waveform diagram when the stepping motor is continuously fed in the forward direction to a mechanical instability point other than the basic step angle. In FIG. 7D, 7a
Reference numerals 4, 7b4, and 7c4 denote a voltage applied to the A-phase coil, a voltage applied to the B-phase coil, and a torque generated by the stepping motor, respectively.

With respect to the stepping motor drive voltage expressed as described above, the operation at the start of continuous feed will be described below with reference to FIGS. 7 (a), 7 (b) and 10.

As shown in FIG. 7A and FIG. 10, when continuous feed is performed in the forward direction from the basic step angle position 10X,
The drive voltage to the next forward basic step angle position 10Z after 10X is applied to the A-phase and B-phase coils, and then only the drive voltage to the basic step angle position is applied to the A-phase and B-phase coils in succession. Since a constant voltage is always applied to both the A-phase and B-phase coils during feeding, the stepping motor can be driven without torque fluctuation.

As shown in FIG. 7B and FIG.
When performing continuous feed in the forward direction from the mechanical instability point 10Y other than the basic step angle, a drive voltage to the nearest basic step angle 10Z in the forward direction of 10Y is applied to the A-phase and B-phase coils, and thereafter By sequentially applying only the drive voltage to the basic step angle position to the A-phase and B-phase coils, a constant current is always applied to both the A-phase and B-phase coils during continuous feed. Can be driven. Next, the operation at the end of the continuous feed will be described with reference to FIGS. 7 (c), 7 (d) and 10. However, during continuous feed, only the drive voltage to the basic step angle is applied to the A-phase and B-phase coils.

As shown in FIGS. 7 (c) and 10, when the continuous feed in the forward direction ends at the basic step angle position 10Z, the drive voltage to the last basic step angle position Z is changed to the A phase and the B phase. And the continuous feed drive of the stepping motor ends without torque fluctuation.

As shown in FIG. 7D and FIG. 10, when the continuous feed in the forward direction ends at a mechanical instability point Y other than the basic step angle, only the last 10Y is driven. By applying a drive voltage to the mechanical instability point to the A-phase coil and making the magnitude of the drive voltage larger than the coil voltage to the basic step angle for a certain period of time, preventing a decrease in torque generated at the time of stoppage Thereby, the movement accuracy to the mechanical instability point 10Y can be improved.

[0053]

As described above, the optical information recording / reproducing apparatus according to the present invention measures the pulse rate and the pulse rate change rate, and switches the pulse rate change rate and the drive voltage of the stepping motor in accordance with the measured values. This enables the optical pickup to be moved in an optimal state. In addition, during acceleration, the stepping motor is driven with the maximum torque, and the pulse rate change rate is varied so as not to generate excess torque, so that stable and high-speed access can be easily realized by suppressing vibration.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical information recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2A is a waveform diagram showing a stepping motor driving pulse rate in the first embodiment of the present invention. FIG. 2B is a waveform diagram showing a stepping motor generated torque in the first embodiment of the present invention. FIG. 4 is a waveform chart showing a stepping motor drive voltage according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of an optical information recording / reproducing device according to a second embodiment of the present invention.

FIG. 4 is a waveform diagram showing a coil voltage of a stepping motor according to a second embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of an optical information recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of an optical information recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 7A is a waveform diagram when the stepping motor is continuously fed in the forward direction from the basic step angle, and FIG. 7B is a waveform diagram when the stepping motor is continuously fed in the forward direction from a mechanical instability point other than the basic step angle. Waveform diagram (c) is a waveform diagram when the stepping motor is continuously fed in the forward direction to the basic step angle. (D) is a waveform diagram when the stepping motor is continuously fed in the forward direction to a mechanical instability point other than the basic step angle.

FIG. 8 is a block diagram showing a configuration of a conventional optical information recording / reproducing apparatus.

9A is a waveform diagram showing a conventional stepping motor driving pulse rate, and FIG. 9B is a waveform diagram showing a conventional stepping motor generated torque.

FIG. 10 is a configuration diagram of a stepping motor.

FIG. 11 is a waveform diagram showing coil voltage in a conventional stepping motor in a 1-2-phase excitation system.

FIG. 12 is a waveform diagram showing a coil voltage and a stepping motor rotation angular displacement of a conventional stepping motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc 2 Spindle motor 3 Optical pickup 4 Objective lens 5 Focus servo means 6 Tracking servo means 7 Stepping motor 8 Stepping motor driving means 9 Optical pickup position detecting means 10 Number of pulses calculating means 11 Pulse rate pattern creating means 12 Lead screw 13 Pulse rate Measuring means 14 Drive voltage varying means 15 Pulse rate change rate measuring means 16 Pulse rate pattern varying means

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor ▲ Yoshi ▼ Shuichi Tadashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Inside the company (72) Inventor Kiyoshi Masaki 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (14)

[Claims] 1. A disc on which information is spirally recorded, a motor for rotating the disc, an optical pickup means for reading information recorded on the disc while following an information track, and Traversing means having a stepping motor for moving the optical pickup means by a predetermined distance; stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor; and varying the frequency of the pulse signal And an optical information recording / reproducing apparatus. 2. The means for varying the frequency of a pulse signal includes means for creating a temporal change pattern of frequency and means for varying the temporal change pattern. 2. The optical information recording / reproducing apparatus according to 1. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the rate of change of the frequency is reduced as the frequency of the pulse signal increases. 4. A disk on which information is spirally recorded, a motor for rotating the disk, an optical pickup means for reading information recorded on the disk while following information tracks, and Traverse means having a stepping motor for moving the optical pickup means by a predetermined distance; stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor; and pulses applied to the stepping motor. An optical information recording / reproducing apparatus comprising means for varying the amplitude of the drive voltage. 5. The optical information recording / reproducing apparatus according to claim 4, wherein the amplitude of the driving voltage is increased as the frequency of the pulse signal is increased. 6. A disk on which information is spirally recorded, a motor for rotating the disk, an optical pickup means for reading information recorded on the disk while following an information track, and Traverse means having a stepping motor for moving the optical pickup means by a predetermined distance; stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor; and pulses applied to the stepping motor. Means for varying at least one of the rising and falling slopes of the drive voltage. 7. The optical information recording / reproducing apparatus according to claim 6, wherein the slope of the rise or fall of the drive voltage increases as the frequency of the pulse signal increases. 8. A disc on which information is spirally recorded, a motor for rotating the disc, an optical pickup means for reading information recorded on the disc while following an information track, and Traverse means having a stepping motor for moving the optical pickup means by a predetermined distance, stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor, and measuring the frequency of the pulse signal Pulse rate measuring means to
A track speed detecting means for detecting a moving speed of an objective lens mounted on the optical pickup means based on a tracking error signal output by the optical pickup means; and an output of the pulse rate measuring means and the track speed detecting means. Lens vibration detecting means for detecting the amount of vibration of the objective lens based on the output, and applying a pulse-like driving voltage to the stepping motor based on the output of the lens vibration detecting means. Optical information recording / reproducing device. 9. A disc on which information is spirally recorded, a motor for rotating the disc, an optical pickup means for reading information recorded on the disc while following an information track, Traverse means having a stepping motor for moving the optical pickup means by a predetermined distance, stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor, and measuring the frequency of the pulse signal Pulse rate measuring means to
A track speed detecting means for detecting a moving speed of an objective lens mounted on the optical pickup means based on a tracking error signal output by the optical pickup means; and an output of the pulse rate measuring means and the track speed detecting means. A tracking actuator mounted on the optical pickup means and configured to move the objective lens in a tracking direction, the tracking actuator being configured to include a lens vibration detection unit that detects a vibration amount of the objective lens based on an output; A light comprising: tracking servo means for controlling the tracking actuator based on an error signal; and switch means for switching an input to the tracking actuator in the tracking servo means to the lens vibration detecting means. Information recording and reproducing apparatus. 10. A disc on which information is spirally recorded, a motor for rotating the disc, an optical pickup means for reading information recorded on the disc while following an information track, and Traverse means having a stepping motor for moving the optical pickup means by a predetermined distance; stepping motor driving means for driving a stepping motor coil based on a pulse signal for driving the stepping motor; and information track for the optical pickup means. A tracking mode for moving the optical pickup means between information tracks, a movement start mode for transitioning from the tracking mode to the movement mode, and a tracking start mode for transitioning from the movement mode to the start mode. Contain and include stepping The basic step angle of the motor n division (n is an integer of 2 or more) optical information recording and reproducing apparatus according to claim to be provided to be driven small step angle. 11. The optical information recording / reproducing apparatus according to claim 10, wherein a fine step angle drive is performed in the following mode, and a basic step angle drive is performed in the movement mode. 12. In the movement start mode, when the stepping motor is rotated from a mechanical instability point other than the basic step angle, the stepping motor is driven by a pulse signal directed to the nearest basic step angle in the rotation direction. 11. The optical information recording / reproducing device according to claim 10, wherein the process is started. 13. In the following start mode, when a stepping motor is rotated to a mechanical instability point other than the basic step angle, only a pulse signal directed to the last mechanical instability point is set to a fine step angle drive, and all other steps are set to a basic step angle drive. 11. The optical information recording / reproducing apparatus according to claim 10, wherein the optical information recording / reproducing apparatus is a step angle drive. 14. In the following start mode, when the stepping motor is rotated to a mechanical instability point other than the basic step angle, a pulse signal applied to the stepping motor at the start of outputting a pulse signal toward the last mechanical instability point. 11. The optical information recording / reproducing apparatus according to claim 10, wherein the amplitude of the driving voltage is increased for a predetermined time.