JPH0573823A - Magnetic head for magnetic disk device - Google Patents

Abstract

PURPOSE:To promote the recording density without narrowing the width of information to be recorded in a track of a magnetic disk with regard to a magnetic head for magnetic disk device used for recording and reproducing a signal to the rotating magnetic disk. CONSTITUTION:The magnetic head 5 is composed of magnetic poles 11a-11d divided along both directions in the tangential direction of the track 4 of the magnetic disk 3 and in the orthogonal direction to this direction, having coils 12a-12d wound independently around the individual magnetic poles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for a magnetic disk device used for recording / reproducing signals on / from a rotating magnetic disk.

With the increase in the amount of information processing in computer systems in recent years, the capacity and size of magnetic disk devices have been increased, and in order to cope with this, further improvement in the recording density of magnetic disks is desired. It is rare.

[0003]

2. Description of the Related Art FIG. 8 is a perspective view of a conventional magnetic head 81. The magnetic head 81 is made of Fe—Ni alloy or the like, and has two magnetic poles 82 a and 82 b divided along the tangential direction of the track 4 of the magnetic disk 3 and one magnetic pole 82.
and a coil 83 wound around a.

By passing a write current through the coil 83 and switching the direction of the current between a forward direction and a reverse direction, the track 4 is magnetized in two types along the tangential direction and in the opposite directions. State information SD
1, 2 are recorded.

[0005]

When the above-described conventional magnetic head 81 is used, in order to further improve the recording density, the width of each information SD1 and SD2 (the length of the track 4 in the tangential direction). However, there is a limit in terms of manufacturing technology of the magnetic head 81 and reliability of recording and reproduction.

Even when perpendicular recording is performed instead of longitudinal recording as described above, since there are two types of magnetization states, the width of information must be reduced in order to improve the recording density. No, there is still a limit to this.

It is an object of the present invention to provide a magnetic head capable of improving the recording density without reducing the width of the information recorded on the track of the magnetic disk.

[0008]

In order to solve the above-mentioned problems, a magnetic head according to the invention of claim 1 provides a signal to a rotating magnetic disk 3 as shown in FIGS. 1, 5 and 6. In the magnetic heads 5, 5a, 5b for the magnetic disk device for recording and reproducing data, magnetic poles 11a to 11d divided along both the tangential direction of the track 4 of the magnetic disk 3 and the direction orthogonal thereto, The magnetic poles are independently wound and coils 12a to 12d.

A magnetic head according to a second aspect of the present invention comprises coils 13a and 13b wound around two magnetic poles adjacent to each other in the direction orthogonal to the tangential direction. In the magnetic head according to the invention of claim 3, the coils 14a, 14b are wound around two magnetic poles adjacent to each other in the tangential direction.
It is configured with.

[0010]

The magnetic pole 11 is divided along both the tangential direction of the track 4 of the magnetic disk 3 and the direction orthogonal to the tangential direction.
Four types of information magnetized in any of the tangential direction and the radial direction are recorded on the magnetic disk 3 by a to 11d.

These four types of information correspond to each magnetic pole 1.
It is read and reproduced by the coils 12a to 12d wound around 1a to 11d. When the coils 13a, 13b or the coils 14a, 14b are provided, the reading of information is performed by the coils 13a, 13b, 14a, 1
4b or in combination with the coils 12a to 12d.

[0012]

1 is a perspective view of a magnetic head 5 according to the present invention,
FIG. 2 is a bottom view of the magnetic head 5 shown in FIG. The magnetic head 5 is made of Fe-Ni alloy or other alloy,
Four magnetic poles 11a to 11d divided along both the tangential direction of the track 4 of the magnetic disk 3 (direction of arrow M1) and the direction orthogonal to this (direction of arrow M2), and
Each of the magnetic poles 11a to 11d has independently wound coils 12a to 12d.

FIG. 3 is a block diagram of a head controller 20 for driving the magnetic head 5 or reproducing a signal from the magnetic head 5. The head controller 21 includes a write controller 22 and a read controller 23. The write controller 22 outputs write signals SW1 to SW4 to the respective coils 12a to 12d of the magnetic head 5 based on the data D0 and D1 for writing 2 bits and the read / write signal R / W.

Further, the read control section 23 synthesizes the read signals SR1 to SR4 from the coils 12a to 12d based on the read / write signal R / W and encodes them to output 2-bit data D0 and D1.

FIG. 4 shows a write signal SW1 for the magnetic head 5.
It is a figure which shows an example of the state of-SW4. Magnetic disk 3
Is written on the track 4 by a combination of turning on and off currents (write signals) in a constant direction with respect to the respective coils 12a to 12d of the magnetic head 5.

For example, in order to write the information SD1 in FIG. 1, as shown in FIG. 4, write signals SW1 and SW are written.
4 is turned on, and the write signals SW2 and SW3 are turned off. As a result, a current flows only in the coils 12a and 12d, and this current causes the magnetic head 5 of the track 4 to move.
Is magnetized in a direction from the outside in the radial direction of the magnetic disk 3 toward the center, and the information SD1 is written.

Similarly, the write signal SW shown in FIG.
The magnetic forces generated in the magnetic poles 11a to 11d are combined by 1 to SW4, and the corresponding information SD is generated.
2 to SD4 are written.

As described above, according to the magnetic head 5, the write signals SW1 to S for the four coils 12a to 12d are written.
By combining W4, information SD1 to SD4 of four types of magnetization states can be recorded, and the recording density is doubled as compared with the conventional longitudinal recording.

Information SD1 to S recorded in this way
When D4 is read by the magnetic head 5, each coil 1
Currents having waveforms of directions and strengths corresponding to changes in the magnetic poles due to the information SD1 to SD4 are generated in 2a to 12d, so that the read control unit 23 synthesizes these currents and records the information SD1 to 2d. 4 is reproduced and data D0, D1
Output as.

FIG. 5 is a perspective view of a magnetic head 5a according to a second embodiment of the present invention. This magnetic head 5a has basically the same structure as the above-mentioned magnetic head 5, and in addition to the structure of the above-mentioned magnetic head 5, a tangential direction of the track 4 of the magnetic disk 3 (direction of arrow M1). ) A coil 13 wound around two magnetic poles 11a and 11b and two magnetic poles 11c and 11d which are adjacent to each other in a direction orthogonal to
It has a and 13b.

The coils 13a and 13b are used for reading the information SD2 and SD4 magnetized in the tangential direction of the track 4. Therefore, in the magnetic head 5a, writing to the magnetic disk 3 is performed by the coil 12a.
Is performed by outputting write signals SW1 to SW4 to .about.12d, and the read from the magnetic disk 3 is read signals SR1 to SR4 from the coils 12a to 12d and read signals SR5 and SR6 from the coils 13a and 13b.
The information SD2 and SD4 magnetized in the tangential direction of the track 4 are read out by the coils 13a and 13b.

According to this magnetic head 5a, the coil 13
Since the currents generated by combining the changes in the magnetic fluxes in the magnetic poles 11a and 11b and the magnetic poles 11c and 11d are generated in a and 13b, respectively, the read signals SR1 to SR4 from the separate coils 12a and 12b and the coils 12c and 12d are generated. The mixing of noise is reduced and the signal-to-noise ratio at the time of reproduction is improved as compared with the case of combining.

FIG. 6 is a perspective view of a magnetic head 5b of a third embodiment according to the present invention, and FIG. 7 shows a head controller 20b for driving the magnetic head 5b of FIG. 6 or reproducing a signal from the magnetic head 5b. It is a block diagram.

This magnetic head 5b has, in addition to the structure of the magnetic head 5a of the second embodiment, a coil wound over two magnetic poles 11b and 11c and two magnetic poles 11a and 11d which are adjacent to each other in the tangential direction of the magnetic disk 3. 14a, 14
b.

The coils 14a and 14b are used for the magnetic disk 3
It is used for reading the information SD1 and SD3 magnetized in the radial direction. Therefore, the magnetic head 5
In b, the write signals SW1 to SW4 are applied to the coils 12a to 12d for writing to the magnetic disk 3 as described above.
Is performed, but the reading from the magnetic disk 3 is performed by the coils 13a, 13b and the coil 14.
This is performed by synthesizing the read signals SR5 to SR8 from a and 14b.

The write controller 24 writes the write signals SW1 to SW to the write coils 12a to 12d of the magnetic head 5b based on the write data DW0 and DW1.
4 is output.

Further, the read control unit 25 includes the coil 13
The read signals SR5 to SR8 from the coils a and 13b and the coils 14a and 14b are combined and encoded to output 2-bit data DR0 and DR1.

According to this magnetic head 5b, the coil 13
a, 13b and coils 14a, 14b each have 2
Since a current is generated by combining the changes in the magnetic flux in one magnetic pole, the mixing of noise is further reduced as compared with the case where the read signals SR1 to SR4 from the separate coils 12a to 12d are combined, and the signal during reproduction is reduced. The noise-to-noise ratio is further improved.

In the above embodiment, independent write signals SW1 to SW1 to coils 12a to 12d, respectively.
SW4 is output, but as shown in FIG. 4, write signals SW1 and SW3 and write signals SW2 and SW
The waveforms of 4 are opposite to each other.
And 12c and the coils 12b and 12d may be connected in series or in parallel, and a write signal may be output to the connected body. In that case, a write signal that changes in the positive and negative directions may be output.

[0030]

According to the present invention, the recording density of the magnetic disk can be improved without reducing the width of the information recorded on the track of the magnetic disk.

According to the inventions of claims 2 and 3, the signal-to-noise ratio can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic head according to the present invention.

FIG. 2 is a bottom view of the magnetic head shown in FIG.

FIG. 3 is a block diagram of a head controller that drives a magnetic head or reproduces a signal from the magnetic head.

FIG. 4 is a diagram showing an example of a write signal to a magnetic head.

FIG. 5 is a perspective view of a magnetic head of a second embodiment according to the present invention.

FIG. 6 is a perspective view of a magnetic head of a third embodiment according to the present invention.

7 is a block diagram of a head controller that drives the magnetic head of FIG. 6 or reproduces a signal from the magnetic head.

FIG. 8 is a perspective view of a conventional magnetic head.

[Explanation of symbols]

 3 magnetic disk 4 track 5, 5a, 5b magnetic head 11a-11d magnetic pole 12a-12d coil 13a, 13b coil 14a, 14b coil

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takenori Oshima 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (3)

[Claims] 1. A tangential direction of a track (4) of a magnetic disk (3) in a magnetic head (5, 5a, 5b) for a magnetic disk device for recording / reproducing a signal to / from a rotating magnetic disk (3). And the magnetic poles (1
1a) (11b) (11c) (11d), and a coil (12a) independently wound for each magnetic pole
(12b) (12c) (12d). A magnetic head for a magnetic disk device, comprising: 2. Coils (13a) (13b) wound around two magnetic poles adjacent to each other in a direction orthogonal to the tangential direction.
The magnetic head for a magnetic disk device according to claim 1, further comprising: 3. A magnetic head for a magnetic disk drive according to claim 1, further comprising coils (14a) (14b) wound around two magnetic poles adjacent to each other in the tangential direction. ..