JP3287862B2 - Disk drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive device which performs coarse adjustment and fine adjustment when tracking a head element on a target track.

[0002]

2. Description of the Related Art In a disk drive device, a head base is provided so as to be movable with respect to a chassis, and a driving force of a motor is transmitted to the head base. A pair of head elements are mounted on the head base, and the pair of head elements are displaced in the radial direction of the disk. In order to control the position of the head element with respect to the target track, fine adjustment is generally performed after coarse adjustment is performed due to demand for quickness. Since the position of the disk is not constant, particularly in the case of a removable disk, the coarse adjustment is performed by moving the head base at high speed based on the rotation angle of an external scale corresponding to the track position of the disk, for example, a stepping motor. The head element is moved to the vicinity of the track (within one track width), and the fine adjustment is to just-track the head element to the target track based on the position information recorded on the disk.

On the other hand, in recent years, the recording density of a disk as a recording medium has been increased, and as a part of this, the track density has been increased and the track width has become extremely narrow. Therefore, the coarse adjustment cannot be performed only by controlling the rotation angle of the stepping motor.
As disclosed in Japanese Patent Publication No. 83, a device using an optical scale has been proposed.

FIG. 7 shows a schematic view of a measuring point using this optical scale. In FIG. 7, an optical scale 50 having slit holes 50a formed at regular intervals is attached to the head base and moves together with the head base. A light-emitting element 51 and a light-receiving element 52 constituting an optical sensor are arranged on the fixed side of the optical scale 50 opposite to both sides facing each other, and a slit plate 53 is interposed between the optical scale 50 and the light-emitting element 51. . When the head base moves, a substantially triangular signal is output from the light receiving element 52, and a scale signal is created from this output signal to perform coarse adjustment.

[0005]

However, in the optical scale 50, a slit hole 50a is formed by an exposure process after a masking process is performed on a glass material or the like.
In this exposure process, the more the light from a single light source is located farther from the light source, the more the incident light is inclined, so that all the slit holes 50a are not formed in the same shape, which causes a deterioration in measurement accuracy. In view of the above, the present invention has been made in view of the fact that there is a limit in the measurement accuracy of an optical scale.
(Registered trademark)) to provide a disk drive device capable of performing coarse adjustment with high accuracy.

[0006]

According to the present invention, there is provided a disk drive apparatus comprising: a head base movably provided by a motor in a radial direction of a mounted disk; In a disk drive device for tracking a head element attached to a table to a target track, a pair of magnetic cells provided on the head base side are provided.
Sensor and a fixed side on the movement locus of this magnetic sensor.
S pole and N pole alternately at twice the interval of the magnetic sensor
And a magnetic scale magnetized on the pair of magnetic sensors.
In the range of -45 ° to + 45 ° of one output signal
The one output signal and one of the pair of magnetic sensors
The output signal in the range of + 45 ° to + 135 °
A signal obtained by inverting the polarity of the other output of the magnetic sensor;
+ 135 ° to + of one output signal of a pair of magnetic sensors
The polarity of the one output signal in the range of 225 ° is inverted.
Inverted signal and one output signal of the pair of magnetic sensors
The magnetic cell in the range of + 225 ° to + 315 °
The signal obtained by adding the other output signal of the
Position signal generating means, and a signal obtained by differentiating the position signal.
Direction signal generating means for forming a direction signal;
A first ratio comparing one output signal of the sensor to the other output
Comparison signal, one output signal of the pair of magnetic sensors and another
Or a second comparison signal that compares the output with the opposite polarity
The pulse obtained at every 1/4 wavelength interval is used as a scale signal.
A scale signal generating means, and the scale signal based on the direction signal;
Set the counting means for counting and the target count value
Target count setting means, and the counting means and
A first ratio for comparing each output from the target count setting means
Comparing means for comparing the position signal with a predetermined voltage value.
Comparison means and the inner circumferential side with respect to the track center of the disc.
A signal recorded with a 1/2 track deviation from the
AB signal for detecting B signal recorded with a / 2 track shift
Signal detection means, and the A signal and the B signal at predetermined timings.
A third comparing means for comparing the signals peak-held at
And the position of the head element with respect to the target track.
When coarsely adjusting the position, the output of the first comparing
Based on the signal obtained by adding the output of the second comparing means
Control the motor to center the track within the target track
When finely adjusting the position of the head element, the third ratio
The motor is controlled based on the output signal of the comparing means .

According to another aspect of the present invention, there is provided a disk drive device, wherein a head base is provided so as to be movable in a radial direction of a mounted disk by a driving force of a motor, and a head element mounted on the head base is moved to a target track. in the disk drive apparatus for tracking, the head base side
Magnetic scale with provided S pole and N pole alternately magnetized
And move at an interval of 1/2 of the magnetization interval of this magnetic scale
A magnetic sensor provided on a fixed side of the trajectory;
Of one output signal of the magnetic sensor from -45 ° to + 45 °
The one output signal in the range and the pair of magnetic cells.
Range of + 45 ° to + 135 ° of one output signal of the sensor
The polarity of the other output of the magnetic sensor at
Signal and +1 of one output signal of the pair of magnetic sensors.
The one output signal in the range of 35 ° to + 225 °
Signal with the polarity reversed, and one of the pair of magnetic sensors
Output signal in the range of + 225 ° to + 315 °
A signal obtained by adding the other output signal of the magnetic sensor
A position signal generating means for forming a position signal;
Direction signal generating means for converting the divided signal into a direction signal;
Compare one output signal and the other output of a pair of magnetic sensors
The first comparison signal and one of the pair of magnetic sensors.
A second comparison of the output signal and the output with the other polarity inverted
Look at the pulse for each quarter wavelength interval obtained from the comparison signal.
A scale signal generating means for forming a scale signal; and
Counting means for counting by a direction signal, and a target cow
Target count setting means for setting a count value;
Output from the target means and the target count setting means
First comparing means for comparing the position signal with a predetermined voltage value.
The second comparing means for comparing the data with the center of the track of the disk
A signal recorded on the inner circumference side shifted by 1/2 track
B signal recorded with a 1/2 track offset from the
AB signal detecting means for outputting the A signal and the B signal
The third comparison of the peak-held signal at the timing of
Comparing means for the target track,
When the position of the pad element is roughly adjusted, the first comparing means
To the signal obtained by adding the output of
Control the motor based on the
When finely adjusting the position of the head element at the center of the rack
The motor is controlled based on the output signal of the third comparing means.
It is intended to be controlled.

[0008]

The magnetic scale is manufactured by moving a magnetic material disposed in the vicinity of a single magnetic head at a constant speed and magnetizing the magnetic material, so that all of the magnetic scales are regularly magnetized.
Therefore, the output of the magnetic sensor for detecting the magnetic force of the magnetic scale can be obtained with extremely high accuracy, and the scale signal generated thereby has high accuracy, so that accurate coarse adjustment can be performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show one embodiment of the present invention. In FIG. 2, a rail 1 is fixed to a chassis (not shown), and a head base 2 is slidably provided on the rail 1. A pair of head elements H (shown in FIG. 1) are attached to the head base 2, and the head base 2 is configured to be moved by a driving force of a motor 3 (shown in FIG. 1). . The movement of the head base 2 causes the head element H to move.
Is displaced in the radial direction of the disk D (shown in FIG. 1).

A groove 1a is formed in the upper surface of the rail 1 in the longitudinal direction, and a magnetic scale 4 is embedded in the groove 1a. The magnetic scale 4 is, for example, a magnescale
(Registered trademark) , a magnetic material is arranged close to a single magnetic head, and this magnetic material is moved at a constant speed to alternately magnetize the S pole and the N pole. Therefore, even if the magnetic scale 4 is regulated and magnetized in all positions and has a long dimension, the magnetization is not disturbed.

A pair of magnetic sensors S ₁ and S ₂ are provided on the bottom side of the head base 2 at a position facing the magnetic scale 4. As shown in FIG. 3, the pair of magnetic sensors S ₁ and S ₂ are arranged in parallel with the moving direction of the head base 2, and the interval d is set to の of the magnetization interval d of the magnetic scale 4. I have. Therefore, the output of the pair of magnetic sensors S ₁ and S ₂ is 9
0 ° phase becomes shifted sine wave, the SIN wave output of convenience one magnetic sensor S ₁ subsequent description, the output of the other of the magnetic sensors S ₂ and COS wave. The magnetic sensors S ₁ , S
₂ can be of any type as long as it produces an output signal proportional to the strength of the magnetic force.

FIG. 1 is a circuit block diagram of a tracking system. In FIG. 1, the outputs of the pair of magnetic sensors S ₁ and S ₂ are both input to the waveform processing circuit 5. The configuration of the waveform processing circuit 5 is shown in FIG.

In FIG. 4, a signal having the SIN wave input and the COS wave input as they are and a signal inverted through the respective inverting circuits 6 and 7 are respectively guided to a selecting circuit 8, and the SIN wave and COS signals are supplied to the selecting circuit 8. Wave, -SIN wave, and -COS wave are input. Further, the SIN wave input is also guided to the switching timing generation circuit 9, and the switching timing generation circuit 9 outputs the SIN wave in the range of -45 ° to 45 ° to 45 °.
In the range of 135 ° to 135 °, the −COS wave is set to 135 ° to 225 °.
The switching control signal is output to the selection circuit 8 to select the -SIN wave in the range of ° and the COS wave in the range of 225 to 315 °. The selection circuit 8 has four switches for selectively outputting four types of input signals, and the opening and closing of the switches are controlled based on a switching control signal.

Each output of the selection circuit 8 is guided to an adder 10, where a signal synthesized is used as a position signal. The position signal is data substantially corresponding to the position between the following scale signals as shown in FIG. The output of the adder 10 is guided to a differentiating circuit 11, and the output of the differentiating circuit 11 is used as a direction signal.

The waveform processing circuit 5 includes two comparators 1
2, 13 and one comparator 12 has a SIN wave and CO
An S wave is guided, and one comparator 12 has a SIN wave> C
An H signal is output at the time of an OS wave. A SIN wave and a −COS wave are guided to the other comparator 13, and the other comparator 1
3 outputs an H signal when −COS wave> SIN wave. The outputs of the comparators 12 and 13 are input to the inverting circuits 14 and 15 to generate inverted signals of SIN-COS> 0 and -SIN-COS> 0.

The outputs of the comparators 12 and 13 and the inverting circuits 1
The outputs 4 and 15 are selectively input to four AND circuits 17 to 20. The AND circuit 17 has (SIN-CO
S)> 0and (−COS−SIN)> 0, the H signal is output, and the AND circuit 18 outputs (SIN−
When the condition of COS)>0and-(-COS-SIN)> 0 is satisfied, an H signal is output. And circuit 19
Is -(-COS-SIN) > 0and- (SIN-CO
S)> 0 is output when the condition of> 0 is satisfied, and the AND circuit 20 outputs (-COS-SIN)> 0and- (SIN).
−H signal is output when the condition of −COS)> 0 is satisfied. From these four AND circuits 17 to 20, A in FIG.
To D are output, and these signals are input to the rising edge detection circuit 21. The rising edge detection circuit 21 outputs a pulse when detecting the rising edge of each input signal, and this pulse is output at a quarter wavelength interval of the SIN wave. This pulse is used as a scale signal.

Returning to FIG. 1, the scale signal and the direction signal of the waveform processing circuit 5 are input to the counter 23. The counter 23 counts up the number of pulses of the scale signal,
When the rising and falling edges of the direction signal are detected, the counting direction is reversed. The output of the counter 23 is a comparator 24
Is led to. The count value setting unit 25 generates a target count value based on a control signal from a CPU (central processing unit) 26 and outputs the target count value to the comparison unit 24. The comparing section 24 compares the count value of the counter 23 with the target count value, and outputs the error as an analog signal.

The position signal of the waveform processing circuit 5 is guided to a comparison unit 27, and a target voltage value of a voltage value setting unit 28 is also guided to the comparison unit 27. The voltage value setting unit 28 is a CPU
The target voltage is generated by the control signal from the control signal 26, but the target voltage value may be constant. The comparing section 27 compares the position signal of the waveform processing circuit 5 with the voltage of the target voltage value and outputs an error signal.

[0019] is led to the adder 29 the output each through a closing switch SW _1, SW ₂ of the comparison unit 24 with the comparison section 27, the opening and closing switch SW _1, SW ₂ are CPU2
6 is controlled by the switching control signal. CPU26
Distinguishes between the coarse adjustment process and the fine adjustment process based on the rotation state of the motor 3 and the like, and closes the switches SW ₁ and SW ₂ in the coarse adjustment process.
In the state and fine adjustment process, the switches SW ₁ and SW ₂ are controlled to be open.

On the other hand, the outputs of the pair of head elements H are guided to an AB detector 31 via an amplifier 30, and are output from the AB detector 31.
Detects the A signal recorded in the A area 41 and the B signal recorded in the B area 42 with reference to the start signal of the index area 40 in FIG. A detected
The signal and the B signal are respectively held by the peak hold circuits 32 and 33 at a voltage value corresponding to the pickup amount. The output of each of the peak hold circuits 32, 33 is
4 and the comparing section 34 outputs the error signal to the adder 29
Output to The output of the adder 29 is the motor driving amplifier 3
5 is supplied to the motor 3 for driving the head base.

In the above configuration, when the target track data is input to the CPU 26 when the head base 2 is at the reference position, coarse adjustment is performed first. That is, the CPU 26 sends a control signal to the count value setting unit 25 and the voltage value setting unit 28. The target count value and the target voltage value are input to the comparison units 24 and 27 by the count value setting unit 25 and the voltage value setting unit 28, and a large error signal is output to the adder 29, so that the motor 3 is driven at high speed.

Then, the pair of magnetic sensors S ₁ and S ₂ move on the magnetic scale 4 to output sine waves, respectively, and the scale signal is output from the waveform processing circuit 5 to the counter 23.
Every time the count value of the counter 23 increases, the error signal of the comparison unit 24 decreases, and the speed of the motor 3 gradually decreases.
Then, when the count value of the counter 23 matches the target count value, the error signal of the comparison unit 24 becomes zero.

When the head base 2 goes too far beyond the target track due to disturbance or the like, the motor 3 rotates in the reverse direction because the positive and negative values of the error signal are opposite. The counter 23 recognizes this reverse rotation based on the direction signal, counts down the subsequent scale signal, and if the count value matches the target count value, the error signal of the comparison unit 24 becomes zero.

When the error signal of the comparison unit 24 becomes zero, only the error signal between the position signal and the target voltage value is obtained. The motor 3 is controlled so that the error signal becomes zero in the same manner as described above, and the coarse adjustment is performed. Ends.

When the coarse adjustment is completed, the switches SW ₁ and SW ₂
Is opened and fine adjustment is started. In the coarse adjustment stage, the head element H is located within a half track width with respect to the center C of the target track, and the head element H picks up the A signal and the B signal. Then, the motor 3 is controlled so that the pickup amounts of the A signal and the B signal are equal to each other, and the track is just-tracked.

In this embodiment, fine adjustment can be performed by using a position signal in addition to the scale signal as a coarse adjustment scale. However, the magnetization pitch of the magnetic scale 4 can be reduced, or a scale signal with a narrow interval can be used. By doing so, coarse adjustment can be performed using only the scale signal.

[0027]

According to the present invention as described above, according to the present invention, header
A pair of magnetic sensors provided on the side of the base, and the magnetic sensors
Is provided on the fixed side on the movement locus of
A magnetic scale with S poles and N poles alternately magnetized at twice the interval
S pole and N pole provided on the head base side
And a magnetic scale that is alternately magnetized
On the fixed side of the trajectory at half the magnetizing interval
And a magnetic sensor, wherein the pair of magnetic sensors
In the range of -45 ° to + 45 ° of one output signal
The one output signal and one of the pair of magnetic sensors
The output signal in the range of + 45 ° to + 135 °
A signal obtained by inverting the polarity of the other output of the magnetic sensor;
+ 135 ° to + of one output signal of a pair of magnetic sensors
The polarity of the one output signal in the range of 225 ° is inverted.
Inverted signal and one output signal of the pair of magnetic sensors
The magnetic cell in the range of + 225 ° to + 315 °
The signal obtained by adding the other output signal of the
Position signal generating means, and a signal obtained by differentiating the position signal.
Direction signal generating means for forming a direction signal;
A first ratio comparing one output signal of the sensor to the other output
Comparison signal, one output signal of the pair of magnetic sensors and another
Or a second comparison signal that compares the output with the opposite polarity
The pulse obtained at every 1/4 wavelength interval is used as a scale signal.
A scale signal generating means, and the scale signal based on the direction signal;
Set the counting means for counting and the target count value
Target count setting means, and the counting means and
A first ratio for comparing each output from the target count setting means
Comparing means for comparing the position signal with a predetermined voltage value.
Comparison means and the inner circumferential side with respect to the track center of the disc.
A signal recorded with a 1/2 track deviation from the
AB signal for detecting B signal recorded with a / 2 track shift
Signal detection means, and the A signal and the B signal at predetermined timings.
A third comparing means for comparing the signals peak-held at
And the position of the head element with respect to the target track.
When coarsely adjusting the position, the output of the first comparing
Based on the signal obtained by adding the output of the second comparing means
Control the motor to center the track within the target track
When finely adjusting the position of the head element, the third ratio
Controlling the motor based on the output signal of the comparing means.
With this arrangement, a sine wave with much higher precision than that of the magnetic sensor is obtained, and the scale signal and the position signal generated by the sine wave are also high in precision.

Further, in the conventional optical scale, only a material having a thermal expansion coefficient is not small, but in the magnetic scale of the present invention, the magnetic expansion coefficient of Cu, Fe, Ni alloy or the like is infinitely close to zero. Since these materials are used, there is also an effect that the use of these materials hardly changes the temperature and improves the accuracy.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a tracking system (embodiment).

FIG. 2 is a perspective view of the vicinity of a head base (example).

FIG. 3 is a diagram showing the relationship between a magnetic sensor and a magnetic scale (Example).

FIG. 4 is a circuit block diagram of a waveform processing circuit (example).

FIG. 5 is an output waveform diagram of each section (Example).

FIG. 6 is a view showing a track pattern of a disk (Example).

FIG. 7 is a schematic view of a measurement point of an optical scale (conventional).

[Explanation of symbols]

2 ... Head base, 3 ... Motor, 4 ... Magnetic scale, 5 ...
Waveform processing circuit, D: disk, H: head element, S ₁ ,
S ₂ : Magnetic sensor.

Continuation of the front page (72) Inventor Hiroyuki Watanabe 1-2-1-11 Ikenota, Taito-ku, Tokyo Inside Iwa Corporation (72) Inventor Yoshihiro Kanda 1-2-11 Ikenota, Taito-ku, Tokyo Inside Aiwa Corporation (72) Inventor Takumi Usui 1-2-1-11 Ikenohata, Taito-ku, Tokyo Inside Iwa Co., Ltd. (56) References JP-A-60-14117 (JP, A) JP-A-60-185269 (JP, A) JP-A-63-132312 (JP, U) JP-B-58-51603 (JP, B2) JP-A-1-180603 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 21 / 08,21 / 02

Claims (2)

(57) [Claims] 1. A disk drive apparatus comprising: a head base movably provided by a motor in a radial direction of a mounted disk; and a head element mounted on the head base tracking a target track. A pair of magnetic sensors provided on the base side, and provided on a fixed side on a movement locus of the magnetic sensors;
The S and N poles are alternately magnetized at twice the interval of the magnetic sensor.
A magnetic scale which, to -45 ° for one of the output signals of the pair of magnetic sensors
The one output signal in the range of + 45 ° and the one output signal;
+ 45 ° to +13 of one output signal of the pair of magnetic sensors
Polarity of the other output of the magnetic sensor in the range of 5 °
And the output of one of the pair of magnetic sensors
The signal in the range of + 135 ° to + 225 ° of the signal;
A signal obtained by inverting the polarity of the other output signal and the pair of magnetic signals
+ 225 ° to + 315 ° of one output signal of the sensor
Add the other output signal of the magnetic sensor in the range
Position signal creating means for making the obtained signal a position signal, and a direction signal for making a signal obtained by differentiating the position signal a direction signal
Generating means for outputting one output signal and the other output of the pair of magnetic sensors;
A first comparison signal compared with one of the pair of magnetic sensors;
Comparison of the output signal of
Pulse for each quarter wavelength interval obtained from the comparison signal of 2
A scale signal generating means for forming a scale signal as a scale signal; and a counter for counting the scale signal by the direction signal.
A counting means, a target count setting means for setting a target count value, and each of the counting means and the target count setting means.
First comparing means for comparing the output, and second comparing means for comparing the position signal with a predetermined voltage value
And 1/2 track toward the inner circumference with respect to the track center of the disc.
A signal recorded with deviation and no 1/2 track on the outer circumference
An AB signal detecting means for detecting a B signal recorded by recording the A signal and the B signal at a predetermined timing;
Third comparing means for comparing the read signals, and coarsely adjusting the position of the head element with respect to the target track.
When adjusting, the output of the first comparing means and the second ratio
The motor is controlled based on the signal obtained by adding the output of the comparing means.
Controlling the head element at the track center within the target track.
When the position is finely adjusted, the output signal of the third comparing means is used.
A disk drive device, wherein the motor is controlled based on: 2. A disk drive apparatus comprising: a head base movably provided in a radial direction of a mounted disk by a driving force of a motor; and a head element mounted on the head base tracking a target track. The S pole and N pole provided on the base side are magnetized alternately.
Magnetic scale and one of the magnetizing intervals of this magnetic scale
The magnetic sensor provided on the fixed side on the movement locus at an interval of 1/2
And -45 ° to one output signal of the pair of magnetic sensors.
The one output signal in the range of + 45 ° and the one output signal;
+ 45 ° to +13 of one output signal of the pair of magnetic sensors
Polarity of the other output of the magnetic sensor in the range of 5 °
And the output of one of the pair of magnetic sensors
The signal in the range of + 135 ° to + 225 ° of the signal;
A signal obtained by inverting the polarity of the other output signal and the pair of magnetic signals
+ 225 ° to + 315 ° of one output signal of the sensor
Add the other output signal of the magnetic sensor in the range
Position signal creating means for making the obtained signal a position signal, and a direction signal for making a signal obtained by differentiating the position signal a direction signal
Generating means for outputting one output signal and the other output of the pair of magnetic sensors;
A first comparison signal compared with one of the pair of magnetic sensors;
Comparison of the output signal of
Pulse for each quarter wavelength interval obtained from the comparison signal of 2
A scale signal generating means for forming a scale signal as a scale signal; and a counter for counting the scale signal by the direction signal.
A counting means, a target count setting means for setting a target count value, and each of the counting means and the target count setting means.
First comparing means for comparing the output, and second comparing means for comparing the position signal with a predetermined voltage value
And 1/2 track toward the inner circumference with respect to the track center of the disc.
A signal recorded with deviation and no 1/2 track on the outer circumference
An AB signal detecting means for detecting a B signal recorded by recording the A signal and the B signal at a predetermined timing;
Third comparing means for comparing the read signals, and coarsely adjusting the position of the head element with respect to the target track.
When adjusting, the output of the first comparing means and the second ratio
The motor is controlled based on the signal obtained by adding the output of the comparing means.
Controlling the head element at the track center within the target track.
When the position is finely adjusted, the output signal of the third comparing means is used.
A disk drive device, wherein the motor is controlled based on: