JPH1153710A - Magnetic head and disk drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record/reproduce data on a standard recording density floppy disk and a high recording density floppy disk. SOLUTION: Two rails 2a and 2b are projected on the surface of a slider 1, opposite to the disk. A head chip 5 of a lower order mode for recording/ reproducing data in contact with the disk is set in the middle position of the rail 2a, while a head chip 6 of an upper order mode is set in the rear side of the rail 2b. The head chip 6 is brought into contact with the disk to record/ reproduce data. When the disk is rotated at high speed, the slider 1 is floated up. Under the floating state of the slider 1, a signal is recorded/reproduced. In order to make a space (a floating amt.) between the disk recording surface and a gap of the head chip 6 a prescribed value, slots 7a and 7b are provided in approximately the middle positions of the rails 2a and 2b. The slot 7a is formed by cutting a place between a recording and reproducing head 51 of the head chip 5 and an erasing head 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic head and a disk drive device applicable to a large-capacity floppy disk compatible with existing floppy disks.

[0002]

2. Description of the Related Art As a removable disk-shaped recording medium, a floppy disk having a large capacity of several tens to several hundreds of megabytes has been proposed as compared with a conventional floppy disk. The increase in the capacity of the floppy disk is achieved by the integration of various technologies such as the material of the recording medium, the structure of the head chip, the processing of the reproduction signal, and the presence or absence of the tracking servo. As one type of large-capacity floppy disk, a floating type disk has been proposed in which data is recorded / reproduced while the magnetic head is slightly lifted from the recording surface of the disk at a high rotational speed of the disk.

[0003] A large-capacity floating-type floppy disk rotates a disk at a high speed and uses the resulting pressure of an air flow to float a magnetic head. The levitation method is a technique employed in a hard disk. Actually, the slider in which the head chip is incorporated flies.

[0004]

The large-capacity Floppy Disk of the floating type that has already been proposed has a problem that it does not have compatibility with existing Floppy Disks, that is, does not have backward compatibility. Therefore, in the next several years, there has been a problem that a floppy disk drive cannot be built in a personal computer in a situation where a current floppy disk is used.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic head and a disk drive capable of recording / reproducing a floppy disk having a conventional standard recording density and a large-capacity floppy disk and realizing backward compatibility. Is to provide.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a first and second rails provided on a slider, which are extended in the direction of rotation of a disk, project in parallel to each other, and project toward the disk. A first rail for recording / reproducing data at a first recording density provided in a substantially central position of the first rail and in contact with the recording surface of the disc.
The head chip and the second rail are provided at a position on the rear side with respect to the rotation direction of the second rail, and record data at a second recording density higher than the first recording density while flying above the recording surface of the disk. And a second head chip for reproduction.

Further, according to the present invention, the first and second rails having substantially the same shape are provided substantially at the center of the first and second rails.
A magnetic head characterized by having a concave portion.

Further, the present invention provides first and second rails which are extended on the slider in a direction of rotation of the disk, project in parallel with the disk, and are provided on the slider, and provided substantially at the center of the first rail. A first head chip for recording / reproducing data at a first recording density in contact with the recording surface of the disc, and a first head chip provided at a position rearward with respect to a rotation direction of the second rail. The second recording medium having the second recording density higher than the first recording density while floating above the recording surface of the disc.
Magnetic head, comprising a second head chip for recording / reproducing data at a recording density of 1, a recording processing circuit for generating recording data to be recorded on the disk by the magnetic head, and reproducing from the disk by the magnetic head And a reproduction processing circuit for processing the reproduced data to be reproduced.

According to the present invention, an existing head chip for recording density (lower mode) and a head chip for high recording density (upper mode) can be incorporated in a common slider, thereby realizing backward compatibility. Can be.

Further, in the present invention, by providing a recess at the center of the rail, the flying height of the head for the upper mode can be made desired.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a magnetic head according to an embodiment of the present invention. FIG. 1A is a bottom view of the slider 1 as viewed from the medium side. FIG. 1B shows FIG.
3A is a side view of the slider 1 as viewed from below. FIG. further,
FIG. 1C shows a state where a part of the slider 1 is cut in a direction orthogonal to the disk rotation direction and a head chip is incorporated. Although not shown, the slider 1 is attached to the tip of a support member such as an arm and is adapted to move in the radial direction of the floppy disk.

Surface (bottom surface) of slider 1 facing disk
, Two rails 2a and 2b extending in the same direction as the disk rotation direction R are formed to protrude. The two rails 2a and 2b are parallel. The front side and the rear side are defined based on the rotation direction R of the disk. On the front side of the slider 1, front tapers 3a, 3b are formed on the rails 2a, 2b, respectively. The rear taper 3a, 3a
b is formed on each of the rails 2a and 2b. As an example, the angle between the front taper and the disk recording surface is 0.5 °, and the angle between the rear taper and the disk recording surface is 10 °.

A head chip 5 for standard density recording (lower mode) is mounted on one of the rails 2a. A head chip 6 for high recording density (upper mode) is provided on the other rail 2b.
Is incorporated. In the lower mode, the disk rotates at a standard speed (for example, 300 [rpm]). At this rotation speed, the slider 1 does not fly, and the head comes into contact with the disk to record / reproduce data. Therefore, the recording / reproducing head 51 and the erasing head 52 of the head chip 5 are arranged at the center where the contact between the slider 1 and the disk surface is most stable.

The head chip 6 is mounted on the rear side of the other rail 2b. The head chip 6 has a structure capable of increasing the linear recording density, for example, MIG (Metal In
Gap) Head structure. Also, since the track density of the lower mode is lower than that of the upper mode, the track width of the head chip 5 is larger than that of the head chip 6 for the upper mode. The width of the rail 2a needs to be larger than the track width of the head chip 5. In order to realize such backward compatibility, reducing the width of the rails 2a and 2b is restricted.

The disk rotates at a high speed (for example, 3600 rpm)
Then, an air flow is generated between the slider 1 and the disk surface, a floating pressure is generated by the air flow, and the slider 1 flies. In addition, by providing the two rails 2a and 2b, the attitude of the slider 1 can be stabilized so that the slider 1 is parallel to the disk surface in a direction perpendicular to the track direction.

Since signals are recorded / reproduced while the disk is rotating at a high speed and the slider 1 is floating, the distance (flying amount) between the disk surface and the gap between the head chip 6 is predetermined (for example, 50). [Nm]). This flying height is defined by the width of the rails 2a and 2b, assuming that the relative peripheral speed of the disk is constant. As an example, the dimensions of the rails 2a, 2b are 0.3 [m
m], the length is 3 mm, and the amount of protrusion from the slider 1 is 0.3 mm.
1 [mm]. This width is a value necessary for incorporating the head chip 5 as described above.

In order to stably control the flying height during rotation to a predetermined value, recesses (hereinafter referred to as slots) 7a and 7b are provided at substantially the center of the rails 2a and 2b. The slots 7a and 7b basically have a function of reducing the floating pressure generated by the air flow between the bottom surface of the slider 1 and the disk surface. At the positions where the slots 7a and 7b are provided, the flying pressure decreases, and the flying pressure on the slider 1 also decreases as a whole. In order to reduce the floating pressure, the slot 7
It is necessary that a and 7b have a certain depth D. As described above, the slots 7a and 7b play a considerable role in appropriately setting the flying height and the attitude of the slider 1 during flying.

By the functions of the slots 7a and 7b, the attitude as viewed from the side of the slider 6 (the state shown in FIG. 1B).
However, the flying height on the front side becomes larger than the flying height on the rear side where the head chip 6 is provided, and the state is slightly inclined. In the flying state, the rear edge of the slider 1 is a stable place where the position hardly fluctuates. Therefore, the head chip 6 of the upper mode is incorporated on the rear side.

When the slot 7a is provided at the center position of the rail 2a, since the head chip 5 is incorporated, the slot 7a is provided between the recording / reproducing head 51 and the erasing head 52.
a is formed. Therefore, the width of the slot 7a cannot be made larger than the interval between these heads 51 and 52. As an example, the distance between the heads 51 and 52 is 350 μm, and the width L of the slot 7a is 35 μm.
0 [μm], for example, when the width L of the slot 7a is 2
00 [μm]. Also, the depth D of the slot 7a
Cannot be made large enough to affect the characteristics of the head for the lower mode. Slot 7b is slot 7
Since the shape is the same as that of the slot 7a, the same restriction occurs for the slot 7b.

FIG. 2 shows the configuration of the head chip 5 for the lower mode in more detail. In FIG. 2, 53a, 53b
Is a U-shaped core made of a magnetic material, and a core 53a,
Coils 56a and 56b are wound around 53b, respectively. Cores 54a and 54b made of a magnetic material are provided so as to be in contact with the respective legs of the cores 53a and 53b.
A spacer 55 made of a non-magnetic material is arranged between the cores 54a and 54b.

A gap of the recording / reproducing head 51 is formed between the core 53a and the core 54a.
4b, a gap of the erasing head 52 is formed.
A slot 7a is formed between the recording / reproducing head 51 and the erasing head 52. That is, the core 54a, the spacer 5
5 and a part of the core 54b are cut, and the slot 7
a is formed. The edge of the slot 7a is processed so as not to damage the disk, as described later.

Referring to FIG. 3, the shape of the slots 7a and 7b will be described. FIG. 3A shows the shape of the slot 70 shown for reference. The slot 70 is an example in which the angle between the surface of the slider 1 facing the disk and the side surface of the slot is a right angle. As described above, the width L of the slot 70 and the depth D thereof are predetermined to make the flying height and the attitude of the slider 1 at the time of flying appropriate. An appropriate value of the depth D will be described later.

Since the slot 70 shown in FIG. 3A has a right-angled edge, when a flexible disk is pushed toward the slot 70 by a floating pressure during rotation, the disk bends so as to enter the slot 70. As a result, there is a problem that the disk comes into contact with the edge, thereby damaging the disk surface. to solve this problem,
In one embodiment, the angle formed between the surface of the slider 1 facing the disk and the side surface of the slot is an obtuse angle. The example shown in FIG. 3B shows a slot 7 having a V-shaped cross section by mechanical processing.
This is an example in which a and 7b are formed. The example shown in FIG. 3C is an example in which trapezoidal slots 7a and 7b each having a tapered side surface and a shallow cross section are formed by ion beam etching.

With the slots 7a and 7b whose edges are obtuse as illustrated in FIGS. 3B and 3C, even if the disk contacts the edges of the slots 7a and 7b, the possibility of damaging the disk can be reduced. . FIG.
B, and in the examples shown in FIG. 3C, by further rounding the edge, it is possible to more reliably prevent the disk from being damaged.

FIG. 4 shows an embodiment in which the slots 7a and 7b are provided at the center position as described above.
9 is a graph showing a result obtained by a computer simulation of a relationship between a depth D of a and 7b and a flying height.
FIG. 4 shows the flying height of the rear edge of the slider 1 provided with the head chip 6 (indicated by a square dot) and the flying height of the front edge (indicated by a circle dot).

In order for the head chip 6 to record data on the disk and to reproduce data from the disk, the flying height of the head chip 6 should be about 0.05 [μm] =
50 nm is an appropriate value. From the graph shown in FIG. 4, focusing on the flying height of the rear edge where the head chip 6 is provided, if the depth D of the slot is smaller than 4 [μm], the flying height is too large and D is 4 [ .mu.m], the flying height can be made substantially the target value. Also, when D is larger than 7 [μm], it can be seen that the flying height is stabilized at substantially the target value. Even if the depth D of the slot is increased, the flying height is substantially constant, and it is not necessary to increase the depth D more than necessary. However, since the head chip 5 is cut by the slot 7a, the depth is preferably up to about 20 [μm].

As described above, in one embodiment, the slots 7a and 7b are provided at the center positions of the rails 2a and 2b, whereby the flying height at the gap position of the head chip 6 in the upper mode is set to a desired value. I have. FIG.
Shows an example of the result obtained by calculating the relationship between the peripheral speed of the floppy disk and the flying height [μm] by computer simulation. In FIG. 5, the change connecting the square dots (the uppermost graph) shows the change in the flying height when no slot is provided. Further, the change (circle in the middle) connecting the circle dots indicates the change in the flying height when the slot is provided near the front side edge. Furthermore, the change (triangle below the graph) connecting the triangular dots indicates the case where the slot is provided at the center position, that is, the change in the flying height of this embodiment. For comparison, the slots in the two cases have the same shape and the same size.

The peripheral speed of a 3.5-inch floppy disk is 10 [m / sec] to 15 [m / sec].
Is used. In this range, the desired flying height is 50
When [nm] is set, both the configuration in which the slot is not provided and the configuration in which the slot is provided on the front side have an excessively large flying height, and it can be seen that one embodiment can obtain a desired flying height. To reduce the flying height, rail 2
Although it is conceivable to narrow the widths of a and 2b, as described above, in order to provide the head chip 5 for the lower mode,
Reducing the width of the rails 2a, 2b is restricted. Also, reducing the rail width has a problem in that the processing accuracy is reduced. Therefore, the width of the rails 2a and 2b is selected to be about 0.3 [mm] as described above.

FIG. 6, FIG. 7, and FIG. 8 show the results obtained by computer simulation of the distribution of the floating pressure on the axis that coincides with the rotation direction R when the disk rotates at high speed. FIG. 6 shows a pressure distribution when no slot is provided. As shown in FIG. 6, since there is no slot, a drop in the floating pressure does not occur. FIG. 7 shows a pressure distribution when a slot is provided on the front side. As shown in FIG. 7, the pressure drops sharply at the position where the slot is provided. FIG. 8 shows a pressure distribution in a case where a slot is provided at the center position, that is, in one embodiment. The pressure drops sharply due to the central slot.

The force that actually lifts the rails 2a and 2b (slider 1) substantially corresponds to the integrated value of the change in the floating pressure (the area of the portion surrounded by the graph) shown in FIGS. 6, 7, and 8, respectively. doing. Therefore, in the pressure change in FIG. 6 where the pressure does not drop, the flying height is the largest. Therefore, the flying height is too large than a desired value. Also, in the case of FIGS. 7 and 8, focusing on the pressure distribution on the rear side from the center position, the integrated value is larger in FIG. 7 and the force for floating the rear side is larger. Since the head chip 6 in the upper mode is incorporated at the rear edge, the flying height of the gap position of the head chip 6 becomes larger than that shown in FIG. 8, and a desired flying height cannot be obtained. As described above, by providing the slots at substantially the center positions of the rails 2a and 2b, a desired flying height can be obtained. Further, by providing the slot at the center position, the difference in pressure between the front and rear of the rail is reduced as compared with the case where the slot is provided on the front side, thereby stabilizing the attitude when flying.

FIG. 9 shows an example of a disk drive using a magnetic head having the above-mentioned backward compatibility. In FIG. 9, reference numeral 11 denotes a floppy disk (standard density or high density) in which tracks are formed concentrically. The floppy disk 11 is rotated by a motor 12 in a CAV (constant angular velocity) system. Reference numeral 13 denotes a magnetic head in which the lower mode head chip 5 and the upper mode head chip 6 are incorporated as shown in FIG.

An amplification circuit 21 and a digital modulation / digital demodulation circuit 2 are provided for the lower mode head chip 5.
2. The formatting / format decomposition circuit 23, the parity generation / error correction circuit 24, the buffer memory 25, and the interface 26 are connected. Similarly, an amplifier circuit 31, a digital modulation / digital demodulation circuit 32, a formatting / format decomposition circuit 33, a parity generation / error correction circuit 34, a buffer memory 35, and an interface 36 are connected to the upper mode head chip 6. You.

Reference numeral 20 denotes a control unit (comprising a microcomputer) for controlling the operation of the entire disk drive. The control unit 20 is supplied with a mode signal from the outside. The mode signal is a signal for instructing one of the upper mode and the lower mode. For example, the mode signal is generated by detecting whether or not there is a hole at a predetermined position of the case of the floppy disk.

When the floppy disk 11 is a lower mode (standard density) floppy disk, the mode signal indicates the lower mode. The control unit 20
In response to this mode signal, the tracking servo is turned off, the interface 26 is operated, and the interface 36 is not operated. In this state, when recording data, recording data from an external computer is stored in the buffer memory 25. The recording data from the buffer memory 25 is a parity generation / ECC circuit 2
4 and error-correction coded by the circuit 24 to generate parity.

The recording data and parity are supplied to a format / format decomposition circuit 23, where they are converted into data of a predetermined format having a sector structure. The formatted data is digitally modulated (for example, MFM) by the digital modulation / demodulation circuit 22. The digital modulation output is supplied to the head chip 5 via the amplifier 21.
Supplied to Then, it is recorded on the disk 11.

The data reproduced by the head chip 5 from the disk 11 is digitally demodulated by the disk modulation / demodulation circuit 22 via the amplifier circuit 21 in a manner opposite to that at the time of recording. And a formatting / format decomposition circuit 2
Parity generation / ECC
The error is corrected by the circuit 24. The data after the error correction is stored in the buffer memory 25. Then, it is taken into an external computer via the interface 26.

Even when the disk 11 is a large-capacity (high-density) floppy disk, data is recorded / reproduced in the same manner as in the lower mode described above. However, the interface 26 is set to the non-operation state, and the interface 3
6 is activated. In order to increase the track density, the tracking servo is turned on. further,
A different digital modulation method from that of the lower mode is adopted. Further, in order to increase the linear recording density, Vidabi decoding or zone CAV may be used. The disk drive device illustrated in FIG. 9 is an example configuration, and various configurations other than those illustrated are also possible. For example, FIG.
Although the low-order mode signal processing system and the high-order mode signal processing system are provided in parallel, some components may be shared. FIG. 9 shows an example in which the recording layer is formed only on one side of the floppy disk 11 for simplicity, but actually, the recording layer is formed on both sides.

[0038]

According to the present invention, a standard recording density (lower mode) head chip is incorporated at one central position of a rail provided in parallel with the slider bottom surface, and a high recording density (upper mode) is mounted on the rear side of the other rail. By incorporating the head chip of (1), a magnetic head having backward compatibility can be configured.

Further, according to the present invention, by providing a recess at the center of the rail, the flying height of the head can be set to a desired value, and the posture during flying can be stabilized.

[Brief description of the drawings]

FIG. 1 is a bottom view, a side view, and a partial sectional view showing a configuration of a magnetic head according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a lower mode head chip according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a shape of a slot according to an embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a relationship between a slot depth and a flying height for describing an embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a change in a flying height with respect to a peripheral speed of a disk.

FIG. 6 is a schematic diagram illustrating a pressure distribution with respect to a position of a rail when a slot is not provided in the rail.

FIG. 7 is a schematic diagram illustrating a pressure distribution with respect to a position of a rail when a slot is provided on a front side of the rail.

FIG. 8 is a schematic diagram illustrating pressure distribution with respect to the position of the rail in one embodiment in which a slot is provided at the center position of the rail.

FIG. 9 is a block diagram showing a configuration of an example of a disk drive using a magnetic head according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Slider, 2a, 2b ... Rail, 5 ...
Head chip for lower mode, 51: Recording / reproducing head, 52: Erase head, 6: Head chip for upper mode, 7a, 7b: Slot

Claims (4)

[Claims] A first rail provided on a slider extending in a disk rotation direction and projecting toward the disk in parallel with each other; a first rail provided on a slider; a disk provided substantially at a center position of the first rail; A first head chip for recording / reproducing data at a first recording density while being in contact with the recording surface of the second rail; and a second head provided at a position rearward with respect to the rotation direction of the second rail. A magnetic head comprising: a second head chip for recording / reproducing data at a second recording density higher than the first recording density while flying above a recording surface of the disk. 2. The magnetic head according to claim 1, wherein first and second recesses having substantially the same shape are provided at substantially center positions of the first and second rails. 3. The recording / reproducing head according to claim 2, wherein the first head chip comprises a recording / reproducing head and an erasing head, and wherein the first and second recesses are formed between the recording / reproducing head and the erasing head. A magnetic head, characterized in that: 4. A first and a second rail extending on a slider extending parallel to each other in the direction of rotation of the disk and projecting toward the disk, and provided at a substantially central position of the first rail. A first head chip for recording / reproducing data at a first recording density while being in contact with the recording surface of the second rail; and a second head provided at a position rearward with respect to the rotation direction of the second rail. A magnetic head comprising: a second head chip for recording / reproducing data at a second recording density higher than the first recording density while flying above the recording surface of the disk; A recording processing circuit for generating recording data to be recorded on the disk; and a reproduction processing circuit for processing reproduction data reproduced from the disk by the magnetic head. Disk drive device.