JPH1011925A - Servo information writing device for magnetic disk drive - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a servo information writing method capable of positioning a head with high accuracy and writing high-quality servo information even when vibration is applied to a carriage. Displacement between an optical head (12) accurately positioned above a disk (1) of a magnetic disk device by an optical head positioning device (13) and a carriage (4) having a servo information writing head mounted on the carriage (4). The signal is amplified by a target 16 made of a detachable cylindrical mirror and detected by a displacement detection circuit 14. A VCM control circuit 6 drives and controls the VCM 5 according to the detected value of the displacement Xd, and moves the carriage 4 to move the optical head. 12, the head on the slider 2 is positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a servo information writing device for a magnetic disk drive.

[0002]

2. Description of the Related Art In a magnetic disk drive, servo information, which is a mark for eliminating a radial deviation from a track of a magnetic disk as a disk-shaped recording medium, is used for positioning a head on a target track. . This servo information is generally externally written using a head of a device called a servo track writer, or
Writing is performed using the head of the magnetic disk device itself. In recent years, as the recording density of magnetic disk devices has increased, the data surface servo method of writing servo information on a part of the data surface has become the mainstream, rather than the servo surface servo method having a disk surface dedicated to servo information. As a result, this servo information is usually written by the latter method.

[0003] In particular, in the case of a small magnetic disk, in order to drive a head and a slider provided with the head to an arbitrary position, the carriage is rotated about a rotation axis due to space and impact resistance problems. A rotary type actuator is used. The positioning of the head at the time of writing the servo information is performed by detecting the position of one point of the carriage with a high-resolution laser length meter and driving the actuator so as to match this position with the target position.

In order to measure the position with a laser length meter, a mirror for reflecting a laser beam is installed at a measurement point. And by installing this mirror,
The mechanism resonance frequency of the actuator is lowered, and furthermore, the mechanism resonance generated at the mirror mounting part is added, so that it is necessary to lower the zero cross frequency of the positioning servo system, which lowers the positioning accuracy of the head. I was On the other hand, the wider the bandwidth of the positioning servo system, the higher the frequency of vibration can be controlled.

Further, the head is moved to a predetermined position by connecting another actuator and a laser length measuring device to the outside, connecting the external actuator and the internal actuator, and positioning the external actuator with the laser length measuring device. In the positioning of the head by the external driving method, the significant deterioration of the mechanism resonance characteristics due to the external actuator and its connection has become a more serious problem.

[0006] As described in Japanese Patent Application Laid-Open No. 5-274833, for example, as described in Japanese Patent Application Laid-Open No. 5-274833, an optical disk plate formed on a head rotation support mechanism and an optical disk mounted on a rotary encoder are used. A method has been proposed in which a head detects a relative displacement between the head rotation support mechanism and the rotary encoder, and positions the head rotation support mechanism so that the value of the relative displacement is kept constant.

[0007]

By the way, the vibration caused by the spindle motor for rotating the magnetic disk and the like is transmitted to the rotating shaft of the carriage and also vibrates the slider including the carriage and the head. In the conventional head positioning method, however, control is performed such that the position measurement point of the carriage is stopped at the target position even with such vibration. Therefore, the vibration transmitted from the rotation axis of the carriage is transmitted with the position measurement point of the stopped carriage as a fulcrum, and the head vibrates without stopping. When the head vibrates, the position of the servo information to be written shifts. That is, when the track is positioned using such servo information, the interval between adjacent tracks is not constant, and data reproduction error may occur due to interference of data in adjacent tracks. Further, with the future increase in recording density of the magnetic disk device, it is expected that the track interval will be narrowed,
It becomes a more important issue.

The vibration transmitted to the head is reversed or amplified depending on the position of the position measurement point of the carriage, and becomes smaller as the measurement point is closer to the head. Therefore, in the method of mounting the optical disk plate as in the prior art, the mechanical resonance characteristics are reduced, and it is difficult to install the optical disk plate near the head. In addition, if the optical disk is reduced in size and weight in order to prevent a reduction in the mechanical resonance characteristics, processing, mounting method, mounting accuracy, and the like of the optical disk become problematic.
In addition, in order to detect displacement with a combination of an optical disk plate and an optical head with high accuracy, it is necessary to shorten the distance between the optical head and the optical disk plate. However, it is difficult to actually arrange the optical head. is there.

SUMMARY OF THE INVENTION It is an object of the present invention to be able to write high-quality servo information without deteriorating the mechanism resonance characteristics of an actuator and positioning a head at a fixed position even when vibration is applied to the carriage from the outside. A method of positioning a head on a disk-shaped recording medium and a method of writing servo information, a magnetic disk device using the method, a servo information writing device for the magnetic disk device, and a displacement detecting mirror for the device To provide.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method of positioning a slider mounted with a head movably supported on a rotating disk-shaped recording medium by a carriage by a carriage driving means. A servo information writing method for writing at least servo information on the rotating disk-shaped recording medium by the head,
The slider or the carriage is provided with detachable reflection means having a reflection surface, accurately positions the optical head with respect to the disk-shaped recording medium, and reflects light from the optical head by the reflection means. An amplified displacement between the optical head and the head is detected based on a change in the angle of light, and the head is positioned based on the detected amplified displacement between the optical head and the head. A servo information writing method for writing servo information on a recording medium has been proposed.

Further, the present invention provides a rotating disk-shaped recording medium, an optical head capable of positioning with high accuracy, an optical head positioning device for positioning the optical head above the disk-shaped recording medium, An optical head comprising: a slider having a head capable of writing information on a disk-shaped recording medium; and a carriage driving means for positioning a head while driving a carriage for moving the slider to the surface of the disk-shaped recording medium. A magnetic disk drive for positioning the head on the disk-shaped recording medium by detecting a relative position between the optical head and the slider, wherein the optical head or a part of the optical head positioning device, and the slider or the carriage drive At least one of the means has a detachable curved reflecting surface. There has been proposed a magnetic disk drive having a device portion for arranging a get, and further having means for detecting a relative position error between the optical head and the slider by reflected light reflected by a reflection surface of the target. You.

Further, the present invention relates to a servo information writing apparatus for a magnetic disk drive for writing servo information on a rotating disk-shaped recording medium of a magnetic disk drive by positioning a head by the above-mentioned servo information writing method. The magnetic disk device can be accurately positioned with respect to the rotating disk-shaped recording medium, and the amplified displacement of the magnetic disk device with respect to the head via a reflector or a reflection means detachable from the carriage can be used. A magnetic disk drive comprising: an optical head having displacement detection means for optically detecting; and a means for outputting a detected displacement from the displacement detection means of the optical head to a means for controlling the position of the head of the magnetic disk drive. Servo information writing device has been proposed.

In addition, the present invention provides a displacement detecting device for use as an optical coupling means of a magnetic disk device, a target of a magnetic disk device, or a curved reflecting surface of a servo information writing device for a magnetic disk device according to the present invention. A detachable displacement detection mirror, which is a mirror formed by processing a reflection film on the surface of a glass tube or a glass rod, has been proposed.

According to the present invention, there is provided an optical coupling means between a slider on which a head of a magnetic disk drive is mounted and an optical head for accurately positioning the slider above a disk-shaped recording medium;
More specifically, a target or the like having a curved reflecting surface is provided in an optical path formed therebetween, thereby detecting the displacement of the slider from the amplified angle change of the reflected light of the light incident from the optical head. Therefore, it is possible to accurately detect the displacement of the head from a distant position without deteriorating the mechanism resonance characteristics of the actuator, eliminate the position detection error due to disturbance displacement transmitted to the carriage, and achieve accurate positioning of the head. Become.

Further, according to the present invention, the target having the reflection surface is formed as a detachable separate member, so that the target can be processed with high precision and the positioning precision can be increased. In addition, it is possible to prevent a decrease in reliability due to gas generation from the adhesive when the target is directly bonded to the carriage. Further, the cost of the magnetic disk can be reduced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a servo information writing device in a magnetic disk drive according to an embodiment of the present invention.
FIG. 1 shows the configuration of a so-called servo track writer. In this figure, reference numeral 1 denotes a disk in which a plurality of magnetic recording disks, which are recording media on which data information and servo information are written, are stacked and held; A slider 3 having a write head for writing at least servo information on the disk 1, a load arm 3 for pressing the slider 2 against the disk 1, a slider 4 supporting the slider 2 via the load arm 3, 5 is a VCM that drives the carriage 4.
(Voice coil motor), 6 is a VCM control circuit that controls the drive current i of the VCM 5 according to the value of a displacement Xd detected by a displacement detection circuit described later, and 7 is a head using the head on the slider 2. A servo information writing circuit for writing servo information on the disk 1, a spindle 8 for laminating and holding a plurality of disks 1, a spindle motor 9 for rotating the spindle 8, and a spindle motor 9 for the spindle motor 9. A spindle motor driving circuit driven by rotation, 11 is an MPU (microprocessor) for controlling the entire operation, 12 is an optical head for detecting the displacement of the slider 2, and 13 is an optical head 12 for moving the optical head 12. An optical head positioning device for accurately positioning the optical head; a displacement detecting circuit for detecting a displacement Xd from an output of the optical head; Shows a clock head for generating a reference made clock for writing servo information.

The plurality of disks 1 are stacked and held on a spindle 8, and the spindle 8 is rotated by a spindle motor 9. The spindle motor 9 is driven by a spindle motor drive circuit 10 and is maintained at a constant rotation speed. The slider 2 is supported by the carriage 4 via the load arm 3, and moves on the disk 1 when the carriage 4 is driven by the VCM 5. Further, the servo information is a disk 1 in which a plurality of disks are stacked and held.
The data is written on the uppermost disk, and on the other hand, in the case of the data surface servo method, on all of those disks. In addition, it goes without saying that the slider 2 having the write head may be capable of writing data information including servo information and reading or erasing them.

The optical head positioning device 13 can perform high-precision positioning using a so-called laser length measuring device or the like, and can position the optical head 12 on the same rotation axis as the slider 2 and on the same radius. Is moved, thereby accurately positioning at a predetermined position.

Next, a so-called target 16 is attached to the back surface of the slider 2 as shown in detail in FIG.
2 detected. Then, the displacement detection circuit 1 of FIG.
In step 4, the relative displacement Xd between the optical head 12 and the slider 2 is detected from the output of the optical head 12. The VCM control circuit 6 shown in FIG. 1 controls the drive current i of the VCM 5 according to the value of the displacement Xd, that is, the displacement Xd.
While driving the carriage 4 so that d is zero (0), that is, the slider 2 is directly below the optical head 12, the slider 2
Position the upper write head.

On the other hand, the clock head 15
First, a clock signal of a constant frequency is written for one rotation outside of the recording area, and when writing servo information, the clock signal is reproduced. That is, servo information is written while the slider 2 is positioned at the target position.
The writing is performed using the write head on the slider 2. At this time, the servo information writing circuit 7 in FIG. 1 writes the servo information 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 flowchart of a procedure for writing servo information. Here, each step is abbreviated by initial "S". First, an HDA (head disk assembly) is installed on the servo track writer shown in FIG. 1 (S1). Next, a command is sent to the spindle motor drive circuit 10 to start the spindle motor 9, and waits for the rotation speed to stabilize (S2). Then, the clock signal is written by the clock head 15 for one rotation (S3). Thereafter, the slider 2 is pressed against and fixed to the outermost stopper (not shown) (S4), and the optical head 12 is moved above the slider 2 (S5). Then, in that state, the carriage 4
Is performed (S6), whereby the slider 2 is brought into a state following the optical head 12. Then, when the slider 2 enters the following state, the optical head 12 is moved to a predetermined servo information writing position at a speed and an acceleration that does not deviate from the following state (S7). Thereafter, the slider 2 is positioned, a command is sent to the servo information writing circuit 7, and the position setting of the optical head 12 and the carriage 4 is repeated (in the case of “N” in S71). If "Y" in S71), the clock head 15
The servo information is written to the disk 1 in synchronization with the clock signal reproduced in step (S8). When the writing of the servo information for one track is completed, it is determined that the writing of the previous servo information is completed (S81). In this manner, the positioning of the slider 2 and the writing of the servo information are repeated ("N" in S81). With the servo information written in all the tracks ("Y" in S81), the spindle motor 9 is stopped ( S9), the writing of the servo information ends.

According to the configuration of the servo information writing apparatus as shown in FIG. 1 of the present invention, the optical head 12 is accurately positioned, the carriage 4 is driven, and the slider 2 follows the optical head 12. By positioning,
Even if vibration is applied to the carriage 4 without lowering the mechanism resonance characteristics of the actuator, the write head on the slider 2 can be positioned at a fixed position, thereby enabling writing of high-quality servo information. This will be specifically described below.

The operation will be described again with reference to FIG.
FIG. 2 is a view showing an example of the relationship between the target 16 mounted on the slider 2 and the optical head 12. In this figure, the optical head 12 emits laser light toward the target 16 and receives the reflected light. Target 16 and optical head 1
2 is detected. This target 16
For example, a cylindrical mirror is mounted so that the axial direction of the cylinder is aligned with the radial direction of the rotational movement of the slider 2, thereby detecting the displacement Xd by a so-called optical lever displacement detection method. .

FIG. 4 shows the principle of displacement detection by the optical lever displacement detection method. In the figure, a cylindrical mirror 1 as a target is shown.
The horizontal movement Pt 6 changes the reflection angle of the laser light incident from the vertical direction, and causes a displacement Pb of the reflected light at the sensor position. This cylindrical mirror 16 has
For example, a mirror-finished cylinder or column having a smooth surface is used. Assuming that the radius of the cylindrical mirror 16 is r, and the distance (lever length) between the laser light reflection surface and the sensor is L, the following relationship is established in a small range of the displacement Pt of the cylindrical mirror 16.

[0026]

Pb ≒ (2 · L / r) · Pt (Equation 1) That is, the displacement Pt of the cylindrical mirror 16 is amplified by selecting the value of the radius r and the lever length L of the cylindrical mirror 16. Can be detected. For example, when r = 1 mm and L = 50 mm, the displacement Pb is enlarged by about 100 times. Therefore, if the displacement resolution of the sensor is 0.1 μm, the displacement detection resolution of the cylindrical mirror 16 is 1 nm, and the displacement is high. Detection becomes possible.
In the displacement detection method, it is not necessary to narrow down the laser beam as in a general optical disk displacement detection method. Therefore, a lens having a long focal length can be used, and the distance (work distance) between the optical head 12 and the target 16 composed of a cylindrical mirror can be used. )
Operability is improved.

Such an optical lever displacement detection method is used, for example, in a scanning tunneling microscope (STM). In STM, two-dimensional displacement detection is performed using a hemispherical mirror as a target. In this embodiment,
A cylindrical mirror is used as the target 16 for the purpose of allowing a one-dimensional displacement to be detected, and for the purpose of allowing a mounting error in the radial direction of the target. When the HDA is installed in the servo track writer, the cylindrical mirror 16 and the optical head 1 are caused by the component accuracy and the assembly accuracy of the HDA and the mounting accuracy of the cylindrical mirror.
The length is required to allow the displacement of 2. However, the HDA is generally made with high precision, and for example, the length of the cylindrical mirror 16 may be about 1 mm. Further, when the cylindrical mirror 16 is made of glass, if r = 1 mm, the mass becomes 0.05 g or less even if an adhesive or the like for attachment is included, and the mechanism resonance characteristic of the actuator is almost reduced. It does not deteriorate.

FIG. 5 shows a target 1 comprising a cylindrical mirror.
FIG. 6 is a diagram showing an example in which the slider 6 is mounted on a load arm 3 that holds the slider 2 instead of the slider 2. In recent years, the shape of the slider 2 has been reduced in size in response to the low flying height of the slider 2 and the like, and it may be impossible to secure a space for mounting the target 16. In such a case, as shown in FIG. 5, the target 16 may be attached to a position close to the head on a member supporting the slider 2 such as the load arm 3. Instead of this structure, as shown in FIG. 6, a target 1 such as a carriage 4 or the like that operates in conjunction with the slider 2 is used.
6 can also be attached.

As shown in FIGS. 7 and 8, a target mounting portion 36 is provided near the VCM coil 35 of the carriage 4.
And the target 16 can be attached. In this case, since the target mounting portion 36 can be made strong, processing and assembling are facilitated, and the target mounting portion 36 does not vibrate, so that highly accurate position detection can be performed. The carriage 4 near the VCM coil 35,
Alternatively, the target 16 may be directly attached to the VCM coil 35.

As such a target 16, for example, a target having a smooth surface such as a glass tube or rod coated with a mirror coating such as a metal film may be used. Further, since the position of the slider 2 is controlled so that the laser beam is incident on a specific position of the target 16, the accuracy of the curvature (radius) of the reflection surface may be within several percent, and a general inexpensive glass tube is used. It is also possible to use Therefore, the target 16 is extremely lightweight and inexpensive as described above, and it is not necessary to remove and reuse the target 16, and the target 16 can be left attached, which improves workability.

FIG. 9 shows the target 1 described above.
6 shows another example of the shape. As shown in this figure, the target 16 may use a cylinder (FIG. 9A) or a part of a cylinder (FIG. 9B), in which case the weight is further reduced. it can. For example, a part of a glass tube may be used, or a resin may be pressed to form a part of a cylinder. As the reflecting surface, not only the above-mentioned convex surface but also a concave surface may be used (FIGS. 9C and 9D). Further, the curvature of the reflection surface does not need to be constant, and may be a cross-section whose curvature changes, for example, an ellipse (FIG. 9E).
Further, if the mounting accuracy of the target 16 is sufficiently ensured, a sphere or a part thereof (FIG. 9 (f)) may be used as the target, in which case the curvature does not need to be constant. In addition, it is not necessary to be a reflecting surface, and a reflecting surface may be used inside the target 16. In other words, the target 16 only needs to convert the horizontal displacement into a reflection angle of the laser beam, and the slider 2, the load arm 3, the carriage 4, and the like are directly subjected to curved surface processing and mirror processing to form a reflection surface. May be.

FIG. 10 shows an embodiment of the optical system of the optical head 12. In the optical system according to this embodiment, LD1
The laser light emitted from 8 is collimated once by a collimator lens 24, condensed by an objective lens 19, and incident on a cylindrical mirror 16 as a target. The reflected light of the laser light by the cylindrical mirror 16 is returned to parallel light again by the objective lens 19, is separated by the beam splitter 20, and is separated by the position detecting element (PSD) 2.
3 is incident. An aperture 25 is arranged between the collimator lens 24 and the beam splitter 20 in order to narrow and reduce the diameter of the beam spot 22 incident on the PSD 23. In such a configuration, the length L of the light lever
Is the distance from the reflecting surface of the cylindrical mirror 16 to the objective lens 19.

FIGS. 11A, 11B and 11C show the structure of a position detecting element (hereinafter referred to as PSD) 23 used as a sensor for detecting the beam spot 22.
And the relationship between the displacement Pb of the beam spot and the displacement output Xd. This PSD23,
It is a sensor capable of detecting the center position of the beam 22 regardless of the intensity or diameter of the beam 22. One type detects a one-dimensional position with one sensor, and the other type detects a two-dimensional position. There is something. In the present embodiment, since one-dimensional displacement detection is sufficient, only the one using a one-dimensional PSD will be described below, but a two-dimensional PSD may be used instead.

The PSD 23 is basically made of the same material as a PD (photodetector), and one element has two output terminals. The photoelectric conversion sensitivity of the output from each output terminal is linear with respect to the position from the output terminal. As is clear from FIG. 12B, zero (0), The maximum value is at the closest position, and 中央 of the maximum value at the center. Therefore, by performing a calculation represented by the following formula from the outputs I1 and I2 from these two output terminals, a displacement output Xd having a constant detection sensitivity is always obtained regardless of the intensity and beam diameter of the beam spot 22. Obtainable.

[0035]

Xd = (I1−I2) / (I1 + I2) (Equation 2) As described above, by using the PSD as a sensor, the displacement detection sensitivity can be kept constant without performing focus control. Thus, stable displacement detection is possible with a simple configuration.

Next, one embodiment of attaching and detaching the target for attaching and detaching the target 16 to and from the carriage 4 will be described with reference to FIGS.
3, FIG. 14 and FIG. FIG.
2 shows a detachable target in which is attached to a leaf spring 40. The leaf spring 40 is bent into a U-shape, and the target 1
6 is attached, and the other two surfaces are bent inward by 90 degrees or less with respect to the surface on which the target 16 is attached.

The attachment / detachment hole 41 is provided for the purpose of inserting the attachment / detachment jig such as tweezers to expand the leaf spring 40 and for easy handling. FIG. 13 is a view of FIG. 12 as viewed from the front. FIG. 14 shows a target mounting portion 36 provided on the carriage 4 for mounting the detachable target of FIG. A rectangular parallelepiped projection is provided near the VCM coil 35 of the carriage 4.

FIG. 15 shows a state where the detachable target of FIG. 12 is mounted on the target mounting portion 36 of FIG. As described above, at the time of writing the servo information, the target mounting portion 36 can be pressed by the two surfaces of the leaf spring 40 of the detachable target by the spring force to fix the detachable target.
After writing the servo information, it can be removed.

Next, another embodiment of the target attaching / detaching mechanism is shown in FIG. 16, FIG. 17, and FIG. FIG. 16 shows a detachable target in which the target 16 is attached to a target holder 45. The target holder 45 includes a spring portion 46 and detachable plates 47 and 48. The detachable plates 47, 48 are attached to the spring portion 46, and can apply a force to the detachable plates 47, 48 to deform them inward. FIG. 17 shows FIG.
6 shows a target mounting portion 36 provided on the carriage 4 for mounting the detachable target 6. VC of carriage 4
A rectangular parallelepiped projection is provided in the approximate shape of the M coil 35, and a mounting groove 49 is provided in this projection.

FIG. 18 shows a state in which the detachable target of FIG. 16 is mounted on the target mounting portion 36 of FIG. As described above, when writing servo information, the detachable target can be fixed with high accuracy by pressing the detachable plates 47 and 48 of the detachable target against the mounting groove 49 of the target mounting portion 36 by the spring force. After writing the servo information, it can be removed.

Next, another embodiment of the target attaching / detaching mechanism is shown in FIGS. 19, 20 and 21. FIG.

FIG. 19 shows a detachable target in which the target 16 is attached to the shape memory alloy material 50. The pressing portions 51 and 52 indicate portions that come into contact with the carriage 4. 19 shows a state where the shape memory alloy material 50 is heated and then mounted on the carriage 4.

FIG. 20 shows a state where the shape memory alloy material 50 in the state of FIG. 19 is cooled. The pressing portions 51 and 52 press the carriage 4 to fix the detachable target to the carriage 4.

FIG. 21 shows the shape memory alloy material 5 in the state of FIG.
0 indicates a heated state. The pressing portions 51 and 52 contract,
Since it is separated from the carriage 4, it can be removed. As described above, the detachable target can be attached when writing the servo information, and the detachable target can be detached after the servo information is written, and the detachable target can be downsized. The attachment / detachment target may be attached to the carriage 4 at any location. Alternatively, a swage hole at the connection between the carriage 4 and the slider suspension 3 shown in FIG. 6 may be used.

Next, another embodiment of the target attaching / detaching mechanism is shown in FIGS. FIG.
Are attached to the carriage 4 by the adhesives 55 and 56, and are attached and detached. As the adhesive, a double-sided tape or the like can be used. This method is light in weight, small, and inexpensive because of its simple configuration.

FIG. 23 shows a structure in which the target 16 is adhered to the carriage 4 with an adhesive 57 and is detached. An adhesive having a low adhesive strength such as an ultraviolet curing resin can be used. This method is light in weight, small, and inexpensive because of its simple configuration.

FIG. 24 shows the case where the target 16 is
Reference numeral 8 designates a structure that is fixed to and detached from the carriage 4. The heat-peelable sheet is one in which the adhesive strength is reduced by heating, and Nitto Denko Corporation's Riba Alpha or the like can be used.
This method is lightweight, compact and inexpensive.

FIG. 25 shows that the plate spring 61 is deformed into a ring shape, and a cylindrical reflecting surface 60 is provided by mirror processing. A mounting groove 62 is provided in the carriage 4, and the leaf spring 61 is fixed to the carriage 4 by the pressing force of the leaf spring 61. This method is light in weight, small, and inexpensive because of its simple configuration.

FIG. 26 shows a state in which the target 16 is attached to the permanent magnet 63 and the permanent magnet 63 is attracted and fixed to the ferromagnetic material 64 provided on the carriage 4. This method
Lightweight, compact, and inexpensive due to simple configuration.

In this embodiment, a laser diode (LD) is used as a light source for the optical head 12. However, this light source does not need to be coherent light such as a laser beam. A light emitting diode (LED) or the like may be used, and the light source is not limited to visible light, and may be infrared light or ultraviolet light. Furthermore, by disposing an interference filter according to the wavelength of the light to be used in front of the photoelectric conversion sensor (PSD23),
The effect of disturbance light can be reduced.

In the embodiment, the optical head 12 is moved to change the relative position with respect to the disk 1. On the contrary, the optical head 12 is fixed and the disk 1 is moved. You may.

In addition, according to the embodiment, in particular, by using the above-described PSD 23 as the photoelectric conversion sensor,
The displacement detection sensitivity can be kept constant without requiring a focus mechanism, and the configuration of the optical head can be simplified. Further, by extending the beam spot in the axial direction of the target, it becomes possible to widen the allowable range of the angle error in which the target is attached.

[0053]

According to the present invention, an optical head capable of accurately positioning a magnetic disk on which servo information is to be written and an amplified displacement of a slider equipped with a head for writing servo information are detected. Thereby, the displacement of the head can be detected with high accuracy, there is no position detection error due to the disturbance displacement transmitted to the carriage, the head can be accurately positioned, and the head can be accurately positioned.
By making the mirror a separate member that can be attached and detached, high precision can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a servo information writing servo track writer according to a head positioning method according to an embodiment of the present invention.

FIG. 2 is a partial perspective view showing a relationship between a target mounted on a slider and an optical head in a servo track writer.

FIG. 3 is a flowchart showing an example of a servo information writing procedure of FIG. 1;

FIG. 4 is an explanatory diagram showing the principle of a displacement detection method using a target.

FIG. 5 is an explanatory diagram showing an example in which a target is mounted on a load arm of a magnetic disk device.

FIG. 6 is an explanatory diagram showing an example in which a target is mounted on a carriage of a magnetic disk device.

FIG. 7 is an explanatory view showing one embodiment in which a target is mounted near a VCM coil of a carriage of a magnetic disk drive.

FIG. 8 is an explanatory view showing another embodiment in which a target is mounted near a VCM coil of a carriage of a magnetic disk drive.

FIG. 9 is a perspective view showing another example of the shape of the target.

FIG. 10 is an explanatory diagram showing another configuration of the optical system of the optical head in the servo track writer of the embodiment.

FIG. 11 is an explanatory diagram showing a configuration of a position detecting element which receives a beam spot reflected by a target and outputs a displacement in the embodiment, and a displacement output relationship thereof.

FIG. 12 is a perspective view showing one embodiment of a configuration of a detachable target using a leaf spring.

FIG. 13 is a front view of FIG. 12;

FIG. 14 is an explanatory diagram of one embodiment of a detachable mounting target provided near the VCM coil.

FIG. 15 is an explanatory diagram in which the detachable target of FIG. 12 is mounted on the target mounting portion of FIG. 14;

FIG. 16 is a perspective view showing another embodiment of the configuration of the detachable target.

FIG. 17 is a perspective view showing one embodiment of a configuration of a detachable target attaching portion provided near the VCM coil.

18 is a perspective view showing a state in which the detachable target shown in FIG. 16 is attached to the target attaching section shown in FIG. 17;

FIG. 19 is an explanatory diagram showing a heating state in one embodiment of a detachable target using a shape memory alloy material.

FIG. 20 is an explanatory diagram showing a state from a heating state to a cooling state in FIG. 19;

FIG. 21 is an explanatory diagram showing a state from a cooling state to a heating state in FIG. 20;

FIG. 22 is an explanatory view showing one embodiment of a configuration for attaching and detaching a target using an adhesive.

FIG. 23 is an explanatory view showing one embodiment of a configuration for attaching and detaching a target using an adhesive.

FIG. 24 is an explanatory view showing one embodiment of a configuration in which a target is attached and detached using a heat release sheet.

FIG. 25 is an explanatory view showing one embodiment of a configuration in which a mirror-processed ring-shaped leaf spring is attached and detached.

FIG. 26 is an explanatory view showing one embodiment of a configuration for attaching and detaching a target using a permanent magnet.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc, 2 ... Slider, 4 ... Carriage, 5 ... V
CM, 12: Optical head, 13: Optical head positioning device,
14: Displacement detection circuit.

Continued on the front page (72) Inventor Marugo Goto 2880 Kozu, Odawara-shi, Kanagawa Storage Systems Division, Hitachi, Ltd.

Claims (1)

[Claims] 1. A slider having a head for writing servo information on a rotating disk-shaped recording medium of a magnetic disk drive, and a light reflecting surface provided on the slider or a member that moves in conjunction with the slider. Reflecting means by a detachable member, and capable of accurately positioning the rotating disk-shaped recording medium of the magnetic disk device, and optically controlling the amplified displacement of the head by reflected light from the reflecting means. Servo information for a magnetic disk drive, comprising: an optical head having a displacement detecting means for detecting, and means for outputting a detected displacement of the optical head from the displacement detecting means to means for controlling a position of a head of the magnetic disk drive. In the writing apparatus, the detachable member having the light reflecting surface is connected to the slider or the slider by a spring force. A servo information writing device for a magnetic disk device, which is fixed to a member that moves and moves.