JPH08124335A - Method for writing servo information and device therefor - Google Patents

Abstract

PURPOSE: To write high quality servo information without deteriorating a mechanical resonance characteristic of an actuator by positioning a head in a fixed position even when a vibration is given to a carriage. CONSTITUTION: A relative displacement Xd between an optical pickup 12 to be positioned by an optical pickup positioning device 13 and a slider 2 recorded on its recording layer with a displacement detecting pattern is detected by a displacement detecting circuit 14. A VCM 5 is controlled to be driven by a VCM control circuit 6 in accordance with a value of the displacement Xd, so that the carriage 4 is moved to make the slider 2 follow the optical pickup 12, and the head on the slider 2 is positioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo information writing method and a writing apparatus, and more particularly to a servo information writing method and a writing apparatus suitable for writing servo information for head track positioning in a magnetic disk device.

[0002]

2. Description of the Related Art Servo information of a magnetic disk device is used to position a head on a target track.
Generally, the servo information is externally written by using the head of the servo writer, or written by using the head of the magnetic disk device itself. In recent years, along with the increase in recording density, the data surface servo that writes servo information in a part of the data surface is more mainstream than the servo surface servo that has a disk surface dedicated to servo information. The servo information is written by the latter method. It is supposed to be.

Further, in the case of a small magnetic disk, due to the problems of space and impact resistance, driving of the head and carriage is
A rotary type actuator that rotates the carriage around the rotation axis is used. Conventionally, the positioning of the head is
The position of one point of the carriage is detected by a high-resolution laser length meter, and the actuator is driven so as to match the target position. To measure the position with a laser length meter, a mirror for reflecting laser light is installed at the measurement point. This mirror lowers the mechanical resonance frequency of the actuator and further adds the mechanical resonance generated at the mirror mounting portion. Therefore, it is necessary to lower the zero-cross frequency of the positioning servo loop, which lowers the positioning accuracy of the head. Furthermore, the external actuator is provided with another actuator and a laser length meter, the external actuator and the internal actuator are connected, and the head is moved to a predetermined position by positioning the external actuator with the laser length meter. In positioning, the significant deterioration of mechanical resonance characteristics due to the external actuator and its connection has become a more serious problem.

For such deterioration of the mechanical resonance characteristic of the actuator, it is mounted on an optical disk plate and a rotary encoder formed on the head rotation support mechanism as described in, for example, Japanese Patent Laid-Open No. 5-274833. A method has been proposed in which the optical head detects a relative displacement between the head rotation support mechanism and the rotary encoder, and positions the head rotation support mechanism so as to keep the value of the relative displacement constant.

[0005]

By the way, the vibration caused by the spindle motor or the like for rotating the magnetic disk is transmitted to the rotary shaft of the carriage to vibrate the carriage and the head. In the conventional head positioning method,
Even with respect to such vibration, the carriage position measurement point is controlled so as to stand still at the target position. Therefore, the vibration transmitted from the rotary shaft of the carriage is transmitted with the position measurement point of the carriage that is stationary as a fulcrum, and the head vibrates without stopping. When the head vibrates, the position of servo information to be written shifts. When positioning a track with such servo information, the interval between adjacent tracks is not constant,
A data reproduction error may occur due to the interference of data on adjacent tracks. Furthermore, it is expected that the track spacing will become narrower as the recording density becomes higher in the future, and the solution of the above problems becomes a more important issue.

The vibrations transmitted to the head have opposite phases or are amplified depending on the position of the position measuring point of the carriage, and become smaller as the measuring point gets closer to the head.
In the method of mounting the optical disk plate as in the above-mentioned known example, it is difficult to install the optical disk plate near the head because the mechanical resonance characteristic is deteriorated. Further, if the optical disc plate is made smaller and lighter in order to prevent the mechanical resonance characteristic from deteriorating, the processing, the mounting method, the mounting accuracy and the like of the optical disc plate become a problem.

The object of the present invention is to position the head at a fixed position and write high-quality servo information without deteriorating the mechanical resonance characteristics of the actuator, and even if vibration is applied to the carriage from the outside. A servo information writing method and a writing device are provided.

[0008]

To achieve the above object, the present invention provides a slider having a head mounted thereon, a slider supporting member, or a carriage with a recording layer whose light reflection state changes, and the recording layer is provided with a laser beam. In advance, the relative position between the optical pickup for detecting the displacement of the slider and the disk-shaped recording medium is recorded by the displacement detection pattern recorded in 1., and the slider is moved based on the output from the optical pickup, The head is positioned based on the relative position to the slider, and servo information is written on the disk-shaped recording medium by the head.

Further, by a carriage driven by a carriage driving means, a slider carrying a head movably supported on the disk-shaped recording medium is positioned, and the head writes servo information on the disk-shaped recording medium. In the information writing method, the slider, the slider supporting member, or the carriage is provided with a recording layer whose light reflection state is changed by irradiation of laser light, and the slider is displaced by a displacement detection pattern recorded by the laser light on the recording layer. The relative position between the optical pickup and the disc-shaped recording medium, the carriage drive means is driven based on the output from the optical pickup to move the carriage, and the optical pickup and the slider are moved. Relative position error is a predetermined target By keeping, it is characterized in that for positioning the head.

Further, a slider for mounting a head movably supported on a disk-shaped recording medium by a carriage, a support member for the slider or the carriage is provided with a displacement detection pattern, and the displacement detection pattern is used for the slider. The relative position between the optical pickup for detecting the displacement and the disc-shaped recording medium is accurately positioned, and the carriage is moved by the carriage driving means for driving the carriage based on the output from the optical pickup, and the optical pickup and the optical pickup are moved. In a servo information writing method of positioning the slider by maintaining a relative position error of the slider at a predetermined target value and writing servo information to the disk-shaped recording medium by the head, the displacement detection pattern with respect to the optical pickup is written. Came in which was set to detect and correct.

Further, a slider for mounting a head movably supported on a disk-shaped recording medium by a carriage, a support member for the slider or the carriage is provided with a displacement detection pattern, and the displacement detection pattern is used for the slider. The relative position between the optical pickup for detecting the displacement and the disc-shaped recording medium is accurately positioned, and the carriage is moved by the carriage driving means for driving the carriage based on the output from the optical pickup, and the optical pickup and the optical pickup are moved. In the servo information writing method, the slider is positioned so as to follow the optical pickup by keeping a relative position error of the slider at a predetermined target value, and servo information is written to the disk-shaped recording medium by the head. Movement information of flop or the disc-shaped recording medium to input as a feedforward information to said carriage driving means is obtained so as to control the movement of the carriage.

[0012]

According to the above construction, the displacement detecting pattern is recorded by the laser on the recording layer provided on the slider on which the head is mounted, the slider supporting member or the carriage, and the displacement of the slider is detected from the displacement detecting pattern in a non-contact manner. The relative position between the optical pickup and the disc-shaped recording medium is accurately positioned, and the carriage is driven to keep the output from the optical pickup at a predetermined target value so that the slider follows the optical pickup. Further, a highly accurate displacement detection pattern can be formed without deteriorating the mechanical resonance characteristics of the actuator, and there is no position detection error due to the disturbance displacement transmitted to the carriage, and the head can be accurately positioned.

Further, by detecting and correcting the inclination of the displacement detection pattern with respect to the optical pickup, it is possible to prevent an error in the detected displacement due to the inclination of the optical axis of the optical pickup, and to accurately position the head. Furthermore, by inputting the movement information of the optical pickup or the disk-shaped recording medium to the carriage driving means as feedforward information, the carriage can be made to follow the optical pickup in a stable manner.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a servo track writer according to an embodiment of the present invention. As shown in Figure 1,
This servo track writer supports a disk 1 on which servo information is written, a slider 2 on which a head for writing servo information on the disk 1 is mounted, a load arm 3 for pressing the slider 2 against the disk 1, and a slider 2 via the load arm 3. A carriage 4 positioned at an arbitrary position on the disk 1, a VCM (voice coil motor) 5 that drives the carriage 4, a VCM control circuit 6 that controls the drive current I of the VCM 5 according to the value of the displacement Xd, and a head on the slider 2. A servo information writing circuit 7 for writing servo information on the disk 1 by using it, a spindle 8 for stacking and holding a plurality of disks 1, a spindle motor 9 for rotating the spindle 8, and a spindle motor drive for driving the spindle motor 9 at a constant rotation. Circuit 10, MPU (micro A processor) 11, an optical pickup 12 for detecting a displacement detection pattern recorded on the recording layer on the back surface of the slider 2, an optical pickup positioning device 13 for moving and accurately positioning the optical pickup 12,
A displacement detection circuit 14 that detects the displacement Xd from the output of the optical pickup 12, a clock head 15 that generates a clock that serves as a reference when writing servo information, and the like.

A plurality of disks 1 are stacked and held on a spindle 8 and are rotated by a spindle motor 9. The spindle motor 9 is driven by a spindle motor drive circuit 10 and kept at a constant rotation speed.
The slider 2 is supported by the carriage 4 via the load arm 3, and is moved on the disk 1 by driving the carriage 4 by the VCM 5.

The optical pickup positioning device 13 is capable of highly accurate positioning using a laser length measuring device or the like, and moves the optical pickup 12 on the same rotation axis and the same radius as the slider 2 to accurately move it to a predetermined position. Position. As shown in FIG. 2, a recording layer 16 is provided on the back surface of the slider 2, and a displacement detection pattern 17 is recorded on it.
This displacement detection pattern 1 by the optical pickup 12
The position of 7 is detected. The displacement detection circuit 14 detects the relative displacement Xd between the optical pickup 12 and the slider 2 from the output of the optical pickup 12. The VCM control circuit 6 controls the drive current I of the VCM 5 according to the value of the displacement Xd, drives the carriage 4 so that the displacement Xd is zero, that is, the slider 2 is directly below the optical pickup 12, and the slider 2 on the slider 2 is moved. Position the head.

The clock head 15 first writes a clock signal of a constant frequency for one rotation outside the recording area of the disk, and reproduces the clock signal when writing servo information. The servo information writing circuit 7 includes a slider 2
With the head positioned at the target position, the head on the slider 2 is used to write the servo information on the disk 1 in synchronization with the clock signal reproduced by the clock head 15.
The MPU 11 controls the entire servo track writer.

FIG. 3 shows a flow chart of a procedure for writing servo information. Hereinafter, the step is abbreviated as S. First, the HDA is installed on the servo track writer (S1), and the position detection pattern 17 is recorded on the recording layer 16 (S2). Next, a command is sent to the spindle motor drive circuit 10 to activate the spindle motor 9 and wait until the number of revolutions stabilizes (S3), and the clock signal is written by the clock head 15 for one revolution (S4). Then, the slider 2 is pressed and fixed to the outermost stopper (S5), and the optical pickup 12 is moved to above the slider 2 (S6). The optical pickup 12 performs autofocus pull-in to focus the laser spot (S7). In that state, the servo of the carriage 4 is pulled in, and the slider 2 is brought into a state of following the optical pickup 12 (S8). When the slider 2 is in the follow-up state, the optical pickup 12 is moved to a predetermined servo information writing position at a speed and an acceleration so as not to miss the follow-up (S9), the slider 2 is positioned, and a command is given to the servo information writing circuit 7. The servo information is sent and the servo information is written to the disk 1 in synchronization with the clock signal reproduced by the clock head 15 (S10). When the writing of the servo information for one track is completed, the optical pickup 12 is moved to the next servo information writing position.
In this way, the positioning of the slider 2 and the writing of the servo information are repeated, and when the servo information is written in all the tracks, the spindle motor 9 is stopped (S11),
Finish writing the servo information.

In the structure shown in FIG. 1, the optical pickup 12 is accurately positioned, and the carriage 4 is driven to position the slider 2 so as to follow the optical pickup 12, thereby lowering the mechanical resonance characteristic of the actuator. Even if vibration is applied to the carriage 4, the head on the slider 2 can be positioned at a fixed position, and high-quality servo information can be written. The details will be described below.

FIG. 2 shows a displacement detecting pattern 17 recorded on a recording layer 16 provided on a slider and an optical pickup 12.
It is a figure which shows an example of the relationship of. The optical pickup 12 emits laser light toward the displacement detection pattern 17 and detects reflected light to detect the relative displacement between the displacement detection pattern 17 and the optical pickup 12. The displacement detection pattern 17 is recorded on the recording layer 16 by irradiation with laser light.
The recording layer 16 is formed by forming a film on the slider 2 by sputtering or the like, which is made of a substance whose light reflection state is changed by laser light irradiation. For example, if a substance that can control the phase change between the crystalline phase and the amorphous phase by the laser light intensity is used, the displacement detection pattern 17 is generated due to the difference in reflectance between the crystalline phase and the amorphous phase.
Can be formed. Optical recording using such a phase change
This is a technology that has been put to practical use in optical disk devices. Less than,
In this embodiment, it is assumed that the reflectance is changed by the phase change and the displacement detection pattern 17 is recorded, and the reflectance of the recorded portion is lowered.

As shown in FIG. 4, the displacement detection pattern 1
Data 7 is recorded by the optical pickup 12 in a state where the spindle motor 9 is stopped at the first stage of writing servo information. FIG. 5 shows an example of the configuration of the optical pickup actuator. Inside the optical pickup 12, the objective lens 20 is supported by a W balance link mechanism 21, and is displaced vertically and horizontally by a magnetic circuit (not shown). Unlike the optical disc pickup, the optical pickup 12 of the present embodiment is arranged so that the horizontal displacement direction of the objective lens 20 is orthogonal to the displacement detection direction. By displacing the objective lens 20 in the horizontal direction, the position of the main spot 18 of the laser beam is moved to record a linear displacement detection pattern 17 as shown in FIG.

FIG. 6 shows a flow chart of a recording procedure of the displacement detection pattern 17. The optical pickup 12 and the slider 2
To the position of the recording layer 16 (S1), and the autofocus is pulled in (S2). Next, the optical pickup positioning device 13 moves the optical pickup 12 to the recording position of the displacement detection pattern 17 (S3), and the actuator in the optical pickup 12 is driven to drive the main spot 18.
Is scanned in a direction orthogonal to the displacement detection direction to record the displacement detection pattern 17 (S4). The movement of the optical pickup 12 and the recording of the displacement detection patterns 17 are repeated to record the necessary number of displacement detection patterns 17. After the recording is completed, the optical pickup positioning device 13 causes the optical pickup 12 to move all the displacement detection patterns 1
7 is moved and the displacement signal Xd is measured (S5).
If the displacement signal Xd is abnormal, change the recording position (S
6) The displacement detection pattern 17 is recorded again. Therefore,
The recording layer 16 is made sufficiently wide so that the displacement detection pattern 17 can be rewritten. If there is no abnormality in the measured displacement signal Xd, a table for linearity correction, which will be described later, is created using this displacement signal Xd (S7), and the recording of the displacement detection pattern 17 ends. When the displacement of the slider 2 is detected, the internal actuator of the optical pickup 12 is locked in the horizontal direction.

By the way, the vertical displacement of the objective lens 20 is caused by the main spot 18 and the sub-spot 1 of the laser beam.
Used for autofocus control of 9a and 19b. In the magnetic disk device, depending on the shape and inclination of the disk 1,
Since the disk surface in contact with the slider 2 moves up and down by about several μm, the slider 2 also moves up and down following this. Therefore, the optical pickup 12 has an autofocus function so that the laser beam can be focused on the displacement detection pattern 17 by following the vertical movement of the slider 2.

The photodetector (PD) 22 receives the reflected light of the main spot 18 and the sub-spots 19a and 19b, and detects the autofocus signal Af and the displacement Xd of the slider 2. As shown in FIG. 7, the optical pickup 12 has two sub-spots 19a and 19b for displacement detection in the displacement detection direction across the main spot 18 at intervals of the line width of the displacement detection pattern 17. Vice spot 19
The powers a and 19b are suppressed to such an extent that the displacement detection pattern 17 does not change. Similarly, when the displacement of the slider 2 is detected, the power of the main spot is lowered.

FIG. 8 shows an example of the structure of the PD 22. PD2
Reference numeral 2 includes a main spot PD 220 that receives the reflected light of the main spot 18, and sub spot PDs 221a and 221b that receive the reflected light of the sub spots 19a and 19b. The difference between the outputs E and F of the sub-spot PDs 221a and 221b is calculated by the displacement detection circuit 14 and output as the displacement Xd.

[0026]

## EQU00001 ## Xd = E-F The main spot PD 220 is divided into four areas, and an autofocus control signal Af is generated from the outputs A, B, C, D of each area by the following equation. To do.

[0027]

## EQU00002 ## Af = (A + D)-(B + C) Further, the push-pull signal Xd 'is generated from the output of the main spot PD 220 by the following equation.

[0028]

## EQU3 ## Xd '= (A + B)-(C + D) The displacement of the slider 2 can also be detected by this push-pull signal Xd', and in that case, the sub-spots 19a and 19b.
Becomes unnecessary. However, the displacement detection sensitivity is less than that of the sub spot 19.
Since it is lower than the displacement Xd detected by a and 19b, high-precision positioning is difficult.

By the way, in FIG. 4, a plurality of linear displacement detection patterns are recorded on the recording layer 16, but this is because the slider 2 moves out of the detection range of the optical pickup 12 due to an external impact or the like. And carriage 4
This is to prevent the runaway. Displacement detection pattern 1
If the number is set to seven, the detection range of the optical pickup 12 is widened, and the possibility of runaway is reduced.

FIG. 9 is a diagram showing an example of the relationship between the displacement detection pattern 17 and the displacement output Xd of the displacement detection circuit 14. The solid line represents the displacement output Xd, which has a shape close to a sine wave. In actuality, in order to stabilize the control and improve the positioning accuracy, the displacement output Xd is linearly corrected and converted into a triangular wave indicated by the dotted line in FIG.
The linearity correction is performed according to the following procedure. First, the optical pickup 12 is scanned in the displacement detection direction to capture the displacement output waveform Xd and approximate it with a sine wave. This sine wave is converted into a triangular wave, and the value of the triangular wave value corresponding to each value of the sine wave is stored in the table. When the displacement is actually detected, the linearity correction is performed by replacing the detected displacement Xd with the value in this table. In this embodiment, a linearity correction table is created when the displacement detection pattern 17 is recorded.

A displacement detecting pattern 17 as shown in FIG.
Even if the slider 2 moves due to an impact, the displacement output Xd
It is possible to return to the original position by counting the number of peaks and moving in the opposite direction by the number of peaks. Figure 10
FIG. 8 is a diagram showing another example of the relationship between the displacement detection pattern 17 and displacement output. By combining the sum A + B + C + D of the detection outputs of the main spots 18 and the displacement detection pattern 17 shown in FIG. 10, it is possible to more reliably detect a specific line. The value of the dotted line Q shown in FIG. 10, which is obtained by binarizing the sum of the main-spot detection outputs with an appropriate threshold, may be used for the detection of this specific line.

The distance between the displacement detection patterns 17 is
It is not limited to the track pitch (1.6 μm or the like) of the optical disc, and is arbitrary. For example, the distance between the displacement detection patterns 17 is made equal to the distance at which servo information is recorded (for example, 1/2 the track pitch). Then, even if the optical pickup 12 is not moved, the displacement detecting pattern 17 to be tracked is shifted by one, whereby the slider 2 can be accurately positioned at the next servo information recording position, and the servo information writing time is shortened. it can. The optical pickup 12 moves a corresponding amount at a time after recording a predetermined number of servo information. Further, the same effect can be obtained even if the interval between the displacement detection patterns 17 is set to be an integral fraction of the interval at which servo information is recorded. At this time, the characteristics of the optical system such as the diameter of the laser spot of the optical pickup 12 are determined by the displacement detection pattern 1
If it is optimized according to the interval of 7, it is possible to detect the displacement with high accuracy.

Further, the flying height of the slider 2 is different between the inner peripheral side and the outer peripheral side of the disk 1 and tilts with respect to the disk surface. This inclination is due to the PD 22 of the reflected light from the optical pickup 12.
The optical pickup 12 has a function of detecting and correcting the inclination of the slider 2 because it causes a positional deviation from the position and an error of the detected displacement Xd. FIG. 11 shows an example of a method for detecting the inclination of the slider 2. The light emitting element 2 is provided on a part of the recording layer 16.
The light of No. 3 is reflected, and the inclination is detected at the position of the reflected light of the light receiving element 24. In the light receiving element 24, a plurality of PDs are linearly positioned, and the inclination of the slider 2 is detected from the position of the PD receiving the light. When the range of the tilt of the slider 2 is narrow, the light receiving element 24 may be a PD divided into two and the tilt may be detected from the output difference of the PD. The optical pickup 12 is tilted according to the tilt thus detected.

Further, the deviation of the beam generated by tilting the optical pickup 12 is corrected by driving the optical pickup positioning device 13 to move the optical pickup 12. However, if the tilt is small enough that the reflected light does not deviate from the PD in the optical pickup,
The error of the displacement Xd may be corrected by calculation. The light emitting element 23 and the light receiving element 24 are the optical pickup 1
2 may be configured inside or may be installed outside the optical pickup 12.

FIG. 12 is a diagram showing an embodiment in which the recording layer 16 and the displacement detection pattern 17 are formed on the load arm 3. In recent years, in response to lower flying height of the slider 2,
The shape of the slider 2 tends to be smaller, and the recording layer 16
It is conceivable that the space for installing the displacement detection pattern 17 cannot be secured. In such a case, as shown in FIG. 12, the recording layer 16 and the displacement detection pattern 17 may be formed at a position near the head on a member supporting the slider 2 such as the load arm 3 or the like.

By the way, in these embodiments, the movement from one track of the slider 2 to the next track is as follows.
Since the movement is performed by following the movement of the optical pickup 12, there is a delay in the movement of the slider 2 with respect to the optical pickup 12, and in some cases the operation may become unstable. Therefore, the optical pickup positioning device 13
The movement information Sf such as the speed and acceleration of the optical pickup 12 is input to the VCM control circuit 6 as feedforward information to drive the carriage 4 and move the slider 2. Therefore, since the movement of the optical pickup 12 is known in advance, the slider 2 can be made to follow stably.

According to the embodiment of the present invention, since the displacement detection pattern 17 is recorded by the optical pickup 12 in a state where the magnetic disk device is attached to the servo track writer, the dimensional error of each component of the magnetic disk device and the servo track. The displacement detection pattern 17 can be formed at an accurate position without being affected by an attachment error to the writer. Further, even if the slider 2 is displaced to some extent by an impact from the outside, the head can be stably positioned on the slider 2 because the detection range of the optical pickup 12 has a width. In the embodiment of the present invention, the optical pickup 12 is moved to change the relative position to the disc 1. However, the optical pickup 12 may be fixed and the disc 1 side may be moved. .

FIG. 13 shows another example in which the structure of the optical pickup actuator is different from that in FIG. The optical pickup 1 displacement detection pattern 17 is recorded by the optical pickup 12 on the servo track writer.
This may be recorded in another recording device after the state of the parts or the device is assembled. In that case, the objective lens 20 of the optical pickup 12 is required to be displaced only in the vertical direction in response to autofocus, and in the displacement detection direction of the slider 2 as in a normal optical disc pickup as shown in FIG. Alternatively, the objective lens may be displaced.

When the optical pickup of FIG. 13 is used, when a large displacement occurs, it can be followed by the displacement of the objective lens 20 of the optical pickup 12, so that the servo system of the slider 2 becomes stable, and the optical pickup 12 is moved, for example. Sometimes the operation of the slider 2 does not become unstable.
When the slider 2 is accurately positioned, it is necessary to detect the displacement Xd of the slider 2 with high accuracy.
The objective lens 20 is fixed at the center of the optical axis. In order to fix the objective lens 20 at the center of the optical axis, the relationship between the displacement output Xd and the push-pull output Xd 'may be expressed by the following equation.

[0040]

## EQU00004 ## Xd-K.Xd '= 0 Here, K is a coefficient for correcting the difference in sensitivity between the displacement output Xd and the push-pull output Xd' with respect to displacement.

The recording layer 16 does not have to be directly formed on the slider or the like, but the recording layer 16 separately formed on a thin substrate or the like may be attached later. As for the material of the recording layer 16, a magnetic layer used in magneto-optical recording is used.
The displacement detection pattern 17 may be configured by a difference in polarization angle of reflected light depending on the magnetization direction, or may be configured by a dye layer,
The reflectance may be changed by destroying the dye layer with laser light, and as long as the reflection state of light is changed by laser light, it is not limited to the above-described embodiments of the present invention. Absent.

Further, the number of the displacement detection patterns 17 is arbitrary, and it is possible to detect displacement sufficiently even with one pattern.
The shape is not limited to the line. The optical pickup 12 also
In combination with the displacement detection pattern 17, the slider 2
Arrangement and number of laser spots are arbitrary as long as the output changes depending on the displacement. The optical pickup actuator is not limited to the Versus method using the W balance link in the above embodiment, but may be a pin method that drives the objective lens around the pin, or any other method.
Further, the beam of the optical pickup 12 is not limited to visible light, but may be infrared light or ultraviolet light, and need not be coherent light such as a laser beam.

By the way, according to the above-described embodiment of the present invention, the head is positioned, the fixed head is installed inside the magnetic disk device, and the fixed head is used as a clock head for writing servo information. It becomes possible to write servo information in. In that case, the recording layer 16 of the slider 2 of the case and the detection range portion of the displacement detection pattern 17 are made transparent windows.

[0044]

According to the present invention, a displacement detecting pattern is recorded by a laser on a recording layer provided on a slider having a head mounted thereon, a slider supporting member, or a carriage, and the displacement of the slider is contactlessly moved from the displacement detecting pattern. The relative position between the optical pickup to be detected and the disk-shaped recording medium is accurately positioned, and the carriage is driven to make the slider follow the optical pickup so that the output from the optical pickup is kept at a predetermined target value. A highly accurate displacement detection pattern can be formed in the vicinity without deteriorating the mechanical resonance characteristics of the actuator, and there is no position detection error due to disturbance displacement transmitted to the carriage, and accurate head positioning is possible.

Further, by detecting and correcting the inclination of the displacement detection pattern with respect to the optical pickup, an error in the detected displacement due to the inclination of the optical axis of the optical pickup can be prevented and the head can be accurately positioned. Furthermore, by inputting the movement information of the optical pickup or the disk-shaped recording medium to the carriage driving means as feedforward information, the carriage can be made to follow the optical pickup in a stable manner.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a servo track writer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a displacement detection pattern formed on a slider and an optical pickup in this embodiment.

FIG. 3 is a flow chart showing an example of a servo information writing procedure in the present embodiment.

FIG. 4 is a diagram showing an example of recording a displacement detection pattern in the present embodiment.

FIG. 5 is a diagram showing an example of a relationship between an optical pickup actuator and a displacement detection pattern in the present embodiment.

FIG. 6 is a flowchart showing an example of a displacement detection pattern recording procedure in the present embodiment.

FIG. 7 is a diagram showing a relationship between a displacement detection pattern, a laser spot, and a displacement output in this embodiment.

FIG. 8 is a diagram showing an example of the configuration of a photodetector of the optical pickup according to the present embodiment.

FIG. 9 is a diagram showing an example of a relationship between displacement detection patterns and displacement outputs in the present embodiment.

FIG. 10 is a diagram showing another example of the relationship between the displacement detection pattern and the displacement output in the present embodiment.

FIG. 11 is a diagram showing an example of a method for detecting the inclination of the slider in the present embodiment.

FIG. 12 is a diagram showing an example in which a displacement detection pattern is formed on a load arm as another embodiment of the present invention.

13 is a diagram showing another example different from the relationship between the optical pickup actuator and the displacement detection pattern shown in FIG.

[Explanation of symbols]

 1 Disk 2 Head 3 Load Arm 4 Carriage 5 VCM (Voice Coil Motor) 6 VCM Control Circuit 7 Servo Information Writing Circuit 8 Spindle 9 Spindle Motor 10 Spindle Motor Drive Circuit 11 MPU (Microprocessor) 12 Optical Pickup 13 Optical Pickup Positioning Device 14 Displacement detection circuit 15 Clock head 16 Recording layer 17 Displacement detection pattern 18 Main spots 19a, 19b Sub-spot 20 Objective lens 22 Photodetector (PD) 220 Main spot PD 221a, 221b Sub-spot PD 23 Light emitting element 24 Light receiving element

Claims (15)

[Claims] 1. A slider on which a head is mounted, a slider supporting member, or a carriage is provided with a recording layer whose light reflection state changes, and displacement of the slider is detected by a displacement detection pattern recorded on the recording layer with laser light. Positioning the relative position between the optical pickup and the disk-shaped recording medium in advance, moving the slider based on the output from the optical pickup, and positioning the head based on the relative position between the optical pickup and the slider, A servo information writing method, wherein servo information is written on the disk-shaped recording medium by the head. 2. A servo for writing servo information on the disk-shaped recording medium by the slider, which is mounted with a head movably supported on the disk-shaped recording medium, by a carriage driven by a carriage driving means. In the information writing method, the slider, the slider supporting member, or the carriage is provided with a recording layer whose light reflection state is changed by irradiation of laser light, and the slider is displaced by a displacement detection pattern recorded by the laser light on the recording layer. The relative position between the optical pickup and the disc-shaped recording medium, the carriage drive means is driven based on the output from the optical pickup to move the carriage, and the optical pickup and the slider are moved. Keep the relative position error at a predetermined target value The servo information writing method is characterized in that the head is positioned thereby. 3. The servo information writing method according to claim 1 or 2, wherein the recording layer is formed by another member in advance and is attached to the slider or the slider supporting member. Method. 4. The servo information writing method according to claim 1, wherein the recording layer comprises a magnetic layer in which a polarization angle of reflected light changes depending on a magnetization direction, and the recording layer is changed in accordance with a change in polarization angle of the reflected light. A servo information writing method, wherein an optical pickup detects displacement of the slider. 5. The servo information writing method according to claim 1, wherein the recording layer is made of a material whose reflectance changes by irradiation with laser light, and the optical pickup changes according to the reflectance of the recording layer. Detecting the displacement of the slider. 6. The servo information writing method according to claim 1 or 2, wherein the recording layer is made of a material capable of controlling a phase change between a crystalline phase and an amorphous phase by the intensity of laser light, A servo information writing method, wherein the optical pickup detects displacement of the slider based on a change in reflectance due to a phase difference. 7. The servo information writing method according to claim 1 or 2, wherein the displacement detection pattern is recorded on the recording layer at a first stage of writing servo information. . 8. The servo information writing method according to claim 7, wherein the displacement detection pattern is recorded on the recording layer by the optical pickup that detects displacement of the slider. . 9. A slider carrying a head movably supported on a disk-shaped recording medium by a carriage,
Alternatively, a displacement detection pattern is provided on the slider support member or the carriage, and the relative position between the optical pickup for detecting the displacement of the slider and the disk-shaped recording medium is positioned by the displacement detection pattern, and the optical pickup Based on the output from the carriage, the carriage is moved by a carriage driving unit that drives the carriage, and the slider is positioned by maintaining the relative position error between the optical pickup and the slider at a predetermined target value, and the head is moved by the head. A servo information writing method for writing servo information to the disk-shaped recording medium, comprising detecting and correcting an inclination of the displacement detection pattern with respect to the optical pickup. 10. A slider having a head movably supported on a disk-shaped recording medium by a carriage, a support member of the slider, or a carriage is provided with a displacement detection pattern, and the displacement detection pattern is used to provide the displacement detection pattern. The relative position of the optical pickup for detecting the displacement of the slider and the disk-shaped recording medium is positioned, and the carriage is moved by the carriage driving means for driving the carriage based on the output from the optical pickup, and the optical pickup and In the servo information writing method, the slider is positioned so as to follow the pickup by keeping a relative position error of the slider at a predetermined target value, and servo information is written to the disk-shaped recording medium by the head. if In addition, the servo information writing method is characterized in that movement information of the disc-shaped recording medium is input to the carriage driving means as feedforward information to control movement of the carriage. 11. A magnetic disk drive in which servo information is written by the method for writing servo information according to claim 1 or 2. 12. A displacement detecting pattern is formed on a slider, a slider supporting member or a carriage,
A magnetic disk device, wherein a window capable of detecting the displacement detection pattern from the outside is provided in the housing. 13. A recording layer, which is formed on a slider, a slider supporting member, or a carriage, and whose light reflection state changes by irradiation of laser light, and a displacement detection pattern can be externally recorded and detected on the recording layer. A magnetic disk device characterized in that a possible window is provided in the housing. 14. A recording medium on which servo information is written, a head for writing servo information on the recording medium, a slider on which the head is mounted, a carriage for movably supporting the slider on the recording medium, and A carriage driving means for driving a carriage, a recording layer formed on the slider, the slider supporting member, or the carriage, the reflection state of which is changed by irradiation of a laser beam, and a displacement detection pattern recorded on the recording layer. An optical pickup that detects the displacement of the slider in a non-contact manner by means of positioning, a positioning means that positions the relative position of the optical pickup and the recording medium, and the carriage so that the output from the optical pickup is maintained at a predetermined target value. A servo information writing device comprising a control circuit for controlling a driving means. 15. A recording medium on which servo information is written, a head for writing servo information on the recording medium, a slider on which the head is mounted, a carriage for movably supporting the slider on the recording medium, and A carriage driving means for driving a carriage; a displacement detecting pattern formed on the slider, the slider supporting member or the carriage; an optical pickup for detecting the displacement of the slider in a non-contact manner by the displacement detecting pattern; Positioning means for positioning the relative position of the optical pickup and the recording medium, inclination correction means for detecting and correcting the inclination of the displacement detection pattern with respect to the optical pickup, and output from the optical pickup to a predetermined target value. Control for controlling the carriage driving means so as to keep Servo information writing device consisting of a road.