JP2003059221A - Loading method for head slider, and disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loading method for a head slider and a disk apparatus adopting the load/unload system that can reduce a possibility of collision between the head slider and a recording medium even in the case of the head slider whose floating amount is as small as several tens of nanometers. SOLUTION: The head slider approaches the surface of the recording medium along a slope from a top of a swell existing on the surface toward the bottom of the swell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for loading a flying type head slider onto a recording medium, and a flying type magnetic disk device, optical disk device, magneto-optical disk device or the like using the same. The present invention relates to a load / unload type recording / reproducing apparatus having a head slider.

[0002]

2. Description of the Related Art Conventionally, in a disk device such as a magnetic disk device, an optical disk device, or a magneto-optical disk device using a flying head slider, the distance between the head slider and the recording medium during recording / reproducing ( Keeping the flying height constant), that is, improving the followability of the head slider to the recording medium, is the most important issue for obtaining desired characteristics such as high reproducibility during recording and reproduction.

The main factors that cause the flying height to fluctuate during recording and reproduction are disturbances such as vibrations and drops, and vertical movements of the medium surface when the recording medium is rotated due to mounting errors that occur during the manufacture of the disk device. That is, there is a runout.

Conventionally, in order to eliminate the influence of factors such as disturbances such as vibrations and drops, the development of a head support mechanism for maintaining a stable flying height and the design of the air-lubricated surface of the head slider for improving the followability. And so on.

Further, with respect to the surface runout caused by the deviation of the mounting angle of the recording medium with respect to the rotation axis, for example, the amount of the surface runout is measured by a sensor and the flying height is made constant by supplementing the amount of the surface runout. In order to achieve this, a technique for moving the head support mechanism up and down has been proposed (eg, JP-A-3-288).
No. 382).

[0006]

However, in recent disk devices, especially magnetic disk devices, with the demand for higher capacity and smaller size, and with the drastic increase in recording density of recording media, The flying height required for a recording medium, which is required for a recent head slider, is about 10 (nm), which is extremely smaller than that of the conventional one. It has become clear that another major problem arises in addition to the improvement of the following capability.

Particularly in a load / unload type disk device, when the head slider is loaded on the recording medium, the head slider collides with the recording medium, and in the worst case, the head slider records on the recording medium. It will damage the layers, making recording and playback impossible,
Is the problem.

Conventionally, 10 (n
Since a protective layer having a thickness of about m) is provided, it is unlikely that the recording layer will be damaged by the collision between the head slider and the recording medium. However, recent high density recording for low flying height recording In the medium, the protective layer has a number (n
It was found that the thickness of the recording layer is extremely thin, and therefore the possibility that the collision between the head slider and the recording medium will damage the recording layer is extremely high.

The present invention has been made in view of the above-mentioned problems, and in a load / unload type disk device, even if the head slider has an extremely small flying height of several tens (nm), the loading of the head slider is performed. An object of the present invention is to provide a head slider loading method and a disk device capable of reducing the possibility of collision between the head slider and the recording medium at the time.

[0010]

A method of loading a head slider according to the present invention is characterized in that the head slider is brought close to a surface of a recording medium along a slope from a ridge portion to a valley portion of a waviness. There is. As a result, it is possible to reduce the possibility of collision between the head slider on which the head is mounted and the surface of the recording medium during loading, so that it is possible to perform highly reliable loading of the head slider.

Further, from the time when the apex of the ridge of the undulation on the surface of the recording medium passes directly below the position of the center of gravity of the head slider to the start of loading, the position of a quarter wavelength from the apex of the undulation passes. By doing so, the possibility of collision between the head slider and the surface of the recording medium can be further reduced.

Further, the disk device of the present invention comprises a sensor for measuring the waveform of the undulation of the surface of the recording medium, a head slider, a supporting means for supporting the head slider, and a head slider by the supporting means based on the output from the sensor. The head slider is characterized in that the head slider is brought closer to the surface along the slope extending from the peak to the valley of the undulation.

As a result, it is possible to reduce the possibility of collision between the head slider on which the head is mounted and the surface of the recording medium at the time of loading, so that it is possible to realize a highly reliable loading of the head slider. It becomes possible to provide.

The control means of the head slider may further include storage means for storing the waveform information of the undulation on the surface of the recording medium, based on the waveform information of the undulation measured in advance by the sensor and stored in the storage means. If the waveform of the undulation is measured in advance by controlling the loading timing, it is not necessary to perform the measurement each time the head slider is loaded, so the head slider can be loaded more easily and more reliably. It is possible to provide a disc device that can do this.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In the embodiments of the present invention, a magnetic disk device having a flying magnetic head will be described in detail as an example of the disk device.

The inventors of the present invention have used a load / unload type (hereinafter referred to as L / UL type) magnetic disk device,
The cause of collision between the head slider and the magnetic recording medium was investigated. In addition, AE (Acoustic Emiss)
ion sensor was mounted on the head slider, and the presence or absence of collision between the head slider and the magnetic recording medium was confirmed from the output waveform thereof.

As a result, the relationship between the surface wobbling caused by the waviness of the surface of the magnetic recording medium and the timing when the head slider is loaded onto the magnetic recording medium (hereinafter referred to as the load timing) has a relationship. It was found to affect the rate of collisions with the medium.

The waviness of the surface of the magnetic recording medium is a mounting error with respect to the rotating shaft of the magnetic recording medium, and bending and distortion of the magnetic recording medium during manufacturing of the magnetic recording medium, especially during cooling after molding the substrate. Caused by. The undulation on the surface of the magnetic recording medium has a shape approximated by a waveform having an amplitude of about 1 (μm) and a wavelength of about several (mm).

As described above, it has been clarified that the ratio of collision between the head slider and the magnetic recording medium varies depending on the difference in load timing. Therefore, regarding the correlation between the load timing and the occurrence of collision, investigated.

(First Embodiment) In the present invention,
The air-lubricated surface 22 (hereinafter referred to as ABS surface) has a shape as shown in FIG. 1, a length of 1.235 (mm), and a width of 1.
(Mm) head slider 21 is used, and the waviness of the surface is a sine wave having a wavelength of 6.175 (mm) and an amplitude of 1.0 (μm). The examination was conducted with a relative speed of 8 (m / s).

Further, the load applied from the suspension to the head slider 21 is 2 (gf) (19.6 (m
N)) and loaded by performing a free fall from a height of 10 (μm).

The behavior of the head slider 21 is analyzed by Y. Mitsuya, Y. Morita,
Z. Deng, Synopsis of the In
international Tribology Con
ference Nagasaki, 2000, p28
The numerical analysis program of the dynamic modified Reynolds equation by the time finite element method described in Section 5 was used.

In this analysis, as shown in FIG. 2, the angle formed by the head slider 21 and the traveling direction of the magnetic recording medium 91 is the pitch angle θ, and the minimum distance between the head slider 21 and the magnetic recording medium 91 is h _min. Further, the tangential direction of the surface of the magnetic recording medium 91 at the point where a perpendicular line drawn from the center of gravity 93 of the head slider 21 so as to be orthogonal to its traveling direction intersects with the magnetic recording medium 91, and the bottom surface (ABS surface) of the head slider 21. Angle to the direction relative pitch angle θr
Was used.

Then, the four load timing conditions as shown in FIG. 3 were examined.

The horizontal axis of FIG. 3 shows the coordinates on the magnetic recording medium, and the vertical axis thereof is the head slider 21 on which the magnetic head is mounted.
Of showing the distance h _g between the center of gravity and the magnetic recording medium surface. Solid line 1
Reference numeral 1 denotes a waviness shape on the surface of the magnetic recording medium, and a broken line 12
Indicates the loading locus of the head slider 21, that is, the behavior of the head slider 21.

That is, 1. In Case I, when the minimum portion of the bottom of the undulation valley comes directly below the position of the center of gravity of the head slider 21, the loading is started.

2. In Case II, the timing for starting the loading is set when the position where a quarter wavelength has passed from the minimum of the bottom of the swelling valley is directly below the position of the center of gravity of the head slider 21.

3. In Case III, when the maximum portion of the peak of the undulation reaches directly below the position of the center of gravity of the head slider 21, the loading is started.

4. In Case IV, the loading is started at the time when the portion of the peak of the undulation that has passed a quarter wavelength from the maximum is just below the position of the center of gravity of the head slider 21.

The results of analyzing the behavior of the head slider 21 for each load timing are shown in FIGS.
It will be described with reference to the drawings.

First, the behavior of the head slider 21 is calculated assuming that there is no undulation on the surface of the magnetic recording medium, and the behavior of the head slider 21 is stable at about t = 0.9 (ms) from the start of loading. Then, the loading operation ends (hereinafter, this time is referred to as load time), and the final flying height of the head slider 21 at this time is 16
(Nm).

Next, in each of the above-mentioned load timings (Case I, II, III, IV), the horizontal axis is the time axis showing the time from the start of loading, and the vertical axis is the relative pitch angle θr and The calculation results are shown in order by taking the change in the minimum distance h _min during loading. Further, in the drawings, the shape of the undulation is also shown for reference.

FIG. 4 shows the analysis result in Case I. Looking at the locus of the minimum distance h _min indicated by the solid line 42, it is about 0.7 (m) from the start of loading.
After the elapse of s), the value of the minimum distance h _min becomes negative, and it can be seen that the head slider 21 collides with the surface of the magnetic recording medium. At almost the same time, it can be seen that the value of the relative pitch angle θr indicated by the broken line 43 also becomes a negative value, and it can be seen that the head slider 21 and the surface of the magnetic recording medium collide with each other.

Next, FIG. 5 shows the analysis result in Case II. Looking at the locus of the minimum distance h _min shown by the solid line 52, it is about 0.5 after the loading starts.
After 5 (ms), the value of the minimum distance h _min becomes negative,
It can be seen that the head slider 21 collides with the surface of the magnetic recording medium. At almost the same time, the value of the relative pitch angle θr indicated by the broken line 53 also becomes negative, which also indicates that the head slider 21 collides with the surface of the magnetic recording medium.

Further, FIG. 6 shows the analysis result in Case III, and the minimum distance h shown by the solid line 82 thereof.
Looking at the locus of _min , about 0.4 (ms) after loading starts, the value fluctuates a little, and the value of the relative pitch angle θr shown by the broken line 83 becomes negative. It exhibits unstable behavior. Then, after about 0.75 (ms) from the loading, the minimum distance h
The value of _min becomes almost 0, and the head slider 21 and the magnetic recording medium are likely to come into contact with each other, but about 0.8 (ms)
After that, it can be seen that the value of the minimum distance h _min becomes positive, and the flying characteristic of the head slider 21 becomes stable. Further, it can be seen from the value of the relative pitch angle θr indicated by the broken line 83 that the head slider 21 behaves similarly.

Furthermore, FIG. 7 shows the analysis result in Case IV, and the minimum distance h shown by the solid line 72 thereof.
_From the locus of _min , it can be seen that the head slider 21 and the magnetic recording medium do not collide with each other and the most stable loading is performed among the four conditions.

As a result, the timing of starting the loading starts from the time when the peak of the ridge of the undulation on the surface of the magnetic recording medium, that is, the maximum point, passes immediately below the position of the center of gravity of the head slider 21 on which the magnetic head is mounted. It is desirable to start loading before a position separated by a quarter wavelength of the swell passes (corresponding to Case III to Case IV in this embodiment).
Thus, it can be seen that stable loading can be performed.

The timing for starting loading is Ca
If it is faster than seIII, the possibility of collision with the ridge of the undulations on the surface of the magnetic recording medium during loading increases, and the timing of starting loading is CaseIV.
If it is too late, there is a high possibility that the head slider 21 may collide with the ridge of the undulation before the behavior of the head slider 21 stabilizes.

That is, by loading the head slider 21 along the slope of the surface of the magnetic recording medium from the ridge to the valley of the undulation, the head slider 21 can be stably floated at a low flying height.

By using such a loading method in consideration of the load timing, compared with the conventional method in which the load timing is not considered, the load time is required to pass one wave of the swell just below the head slider 21. Even when the time is longer than that, stable loading can be performed.

(Second Embodiment) Further, by forming a magnetic disk device using the head slider loading method as described in the first embodiment of the present invention, it is more stable than the conventional device. It is possible to form a magnetic disk device capable of loading the head slider.

In the present embodiment, a magnetic disk device using the head slider loading method in consideration of the load timing described in the first embodiment will be described in detail.

The disk device of the present invention is characterized in that it has a sensing means such as an optical sensor or an electrostatic capacitance type sensor as a constituent element in order to realize the above-described method for loading the head slider. And

FIG. 8 is a plan view showing the structure of the disk device of the present invention.

In the magnetic disk device 29, the magnetic recording medium 19 is rotatably held by the spindle motor 5, and its rotation is connected through a flexible printed wiring board (hereinafter referred to as FPC) 27 to control means 23. Controlled by.

Further, the housing 15 is provided with the sensor 14 which is the above-mentioned sensing means. By using this sensor 14, the undulation of the surface of the magnetic recording medium 19, specifically, the sensor 14 and The value of the distance from the surface of the magnetic recording medium 19 is detected.

Here, as the sensor 14, it is possible to use the above-mentioned capacitance type sensor, an optical sensor or the like, and the detected signal is transmitted to the control means 23 via the FPC 27.

A head slider 1 having a magnetic head (not shown) mounted on the side thereof facing the magnetic recording medium 19 is supported by a support arm 2.

The support arm 2 is rotatably held by a rotary shaft 3 and has a voice coil motor (VCM) 3
When the head slider 1 is rotated by the action of 0, the head slider 1 is moved onto an arbitrary track on the magnetic recording medium 19. The voice coil motor 30 includes a coil 16 held by a coil holder 17 provided on the support arm 2,
Magnet 20 provided in housing 15 and housing 15
And a yoke 24 provided on the.

The coil 16 and the control means 23 are connected to the FPC 2
7 are connected, and the current supplied to the coil 16 is controlled by the control means 23, so that the above-described rotation operation can be controlled.

When the rotation of the magnetic recording medium 19 is stopped, the guide portion 2a provided at the tip of the supporting arm 2 is provided with a ramp to prevent the head slider 1 and the magnetic recording medium 19 from contacting and adsorbing. It is held by the holding portion 18b so as to ride on the inclined portion 18a of the portion 18.

The sensor 14 may be provided at any location of the housing 15 capable of detecting the value of the distance from the surface of the magnetic recording medium 19, or the inclined portion 18a of the ramp portion 18 may be used. Surface facing the magnetic recording medium 19 of
That is, it may be provided in the portion shown in the area AA in FIG.

By thus configuring the magnetic disk device 29, during recording / reproduction of the magnetic disk device 29,
Since the head slider 1 can be loaded at a load timing that matches the shape of the undulation while detecting the undulation of the surface of the magnetic recording medium 19, a more stable flying characteristic than that of the conventional magnetic disk device can be obtained. It is possible to provide the magnetic disk device having the same.

The operation will be described in more detail below.

FIG. 9 is a block diagram showing the configuration of the magnetic disk device 29 of the present invention, and the arrows show the flow of signals.

In FIG. 9, the control means 23 is the sensor 1
4 from the sensing information, specifically, the information about the distance between the sensor 14 and the magnetic recording medium 19, and based on the information, sends a control signal to the spindle motor 5 and the voice coil motor 30. , Control.

A specific processing flow of the method of loading the head slider 1 is shown in FIG.

In FIG. 10, first, step S121.
When the loading of the head slider 1 is started, the control means 23 sends a command to the spindle motor 5 to start the rotation.

As a result, the spindle motor 5 rotates and the magnetic recording medium 19 starts rotating.

Next, in step S122, the output signal from the sensor 14, specifically, the numerical value of the distance between the sensor 14 and the surface of the magnetic recording medium 19 is sent to the control means 23. From the numerical value, in step S123, the waviness on the surface of the magnetic recording medium 19 is
Right below the head slider 1, it is judged whether or not the maximum.

When it is determined in step S123 that the undulation is maximum, the timing voice coil motor 3 is controlled by the control means 23 at the time when loading should be started.
A signal for loading 0 is transmitted, and the processing flow ends.

By constructing such a magnetic disk device 29, it is possible to realize the head slider loading method of the present invention.

Further, in order to realize the head slider loading method of the present invention, a magnetic disk device 29 having a storage means 115 as shown in FIG. 11 may be used.

When such a magnetic disk device 29 is used, it is necessary to perform the pretreatment as shown in FIG. 12 before loading the head slider 1.

That is, the shape of the undulation in the portion of the surface of the magnetic recording medium 19 where the head slider 1 is to be loaded is sensed by the sensor 14, and the result is stored in the storage means 115 for each sector. deep.
Note that various well-known memories can be used as the storage unit 115.

In step S161 of FIG. 12, first, the spindle motor 5 is rotated by a command from the control means 23, and at the same time, sensing is performed by the sensor 14 for each index pulse of the spindle motor 5, whereby magnetic recording is performed. Information such as the shape of the medium 19 relating to the waviness of the area where the head slider 1 is to be loaded is acquired, and in the following step S162,
The acquired information is stored in the storage unit 115.

In step S163, when it is confirmed that the information about the swell in all the areas of the track to be loaded by the head slider 1 can be stored, then in step S164, from the information acquired by the storage means 115. The control means 23 calculates the information of the index pulse that maximizes the swell, that is, the optimum area for loading of the track on which the head slider 1 is to be loaded, and in step S165, the position of the index pulse or the like is calculated. The information is stored in the storage unit 115, and the process ends.

The head slider 1 is actually used as the magnetic recording medium 1.
When loading to No. 9, the position information of the optimum area for loading, which is stored in step S165, is called from the storage means 115, and the head slider 1 is always loaded to the optimum area.
A command is transmitted from the control means 23 to the voice coil motor 30.

The magnetic disk device 29 having such a configuration can also realize the head slider loading method of the present invention. In this case, each time the head slider 1 is loaded, the sensor 14 performs sensing. No need.

As described above, in the magnetic disk device 29 having the structure in which the information regarding the optimum area for loading the head slider 1 is acquired in advance, the head slider 1 is mounted without mounting the sensor 14. By maintaining the height substantially unaffected by the undulation and analyzing the intensity of the output from the magnetic head, etc., the undulation state of the surface of the magnetic recording medium 19 is detected, and a similar loading method is realized. It may be configured to do so.

In this case, in the block diagram shown in FIG. 11, a magnetic head is inserted instead of the sensor 14,
In the process flow shown in FIG. 12, step S161
The magnetic head performs the sensing shown in (2).

With such a structure of the magnetic disk device 29, it is possible to realize the head slider loading method of the present invention without separately providing means for detecting the shape of the undulation.

By configuring the magnetic disk device 29 as described in the present embodiment, it is possible to reduce the possibility of collision between the head slider and the magnetic recording medium during loading even when the flying height is low. It is possible to form the disk device 29.

In the embodiments of the present invention, the magnetic head is taken as the head and the magnetic disk device is shown as the disk device. However, the head loading method and the disk device of the present invention are not limited to this. Without limitation, floating heads such as magnetic heads, optical heads, magneto-optical heads, and magnetic disk devices,
It is needless to say that the present invention can be applied to all disk devices including a floating head such as optical disk devices and magneto-optical disk devices.

[0076]

As described above, by using the loading method and the disk device of the present invention, it is possible to reduce the probability of collision between the head slider and the recording medium at the time of loading. Therefore, it is possible to provide a stable and highly reliable disk device.

[Brief description of drawings]

FIG. 1 is a perspective view of a head slider according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a coordinate system according to the first embodiment of this invention.

FIG. 3 is an explanatory diagram of load timing conditions according to the first embodiment of this invention.

FIG. 4 is a diagram showing an example of an analysis result according to the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of an analysis result according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an example of an analysis result according to the first embodiment of the present invention.

FIG. 7 is a diagram showing an example of an analysis result according to the first embodiment of the present invention.

FIG. 8 is a plan view showing the configuration of the disk device of the present invention.

FIG. 9 is a block diagram showing the configuration of a disk device of the present invention.

FIG. 10 is a flowchart showing a processing flow of a head slider loading method of the present invention.

FIG. 11 is a block diagram showing the configuration of a disk device according to the present invention.

FIG. 12 is a flowchart showing a processing flow of a head slider loading method of the present invention.

[Explanation of symbols]

1,21 head slider 2 Support arm 2a Guide part 3 rotation axes 5 Spindle motor 14 sensors 15 housing 16 coils 17 Coil holder 18 Lamp part 18a inclined part 18b holding part 19 magnetic recording media 20 magnets 22 Air lubricated surface (ABS surface) 23 Control means 24 York 27 Flexible Printed Circuit Board (FPC) 29 Magnetic disk unit 30 voice coil motor (VCM) 91 Magnetic recording medium 93 center of gravity 115 storage means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshihiro Ueno             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5D076 AA01 BB01 CC05 FF21 GG12

Claims (4)

[Claims] 1. A method of loading a head slider, characterized in that the head slider is brought close to the surface of a recording medium along a slope extending from a ridge portion to a valley portion of the surface. 2. From the time when the apex of the ridge of the undulation on the surface of the recording medium passes immediately below the position of the center of gravity of the head slider, the position of a quarter wavelength from the apex of the undulation starts from the start of loading. The method of loading a head slider according to claim 1, wherein the method is performed before the head passes. 3. A sensor for measuring the waveform of the waviness of the surface of a recording medium, a head slider, a supporting means for supporting the head slider, and a loading of the head slider by the supporting means based on an output from the sensor. A disk device comprising control means for controlling the timing, wherein the head slider is brought closer to the surface along a slope extending from the ridge to the valley. 4. The control means further comprising storage means for storing undulation waveform information of the surface of the recording medium, the control being based on the undulation waveform information measured in advance by the sensor and stored in the storage means. 4. The disk drive according to claim 3, wherein the means controls the loading timing of the head slider.