JP2529077Y2 - Magnetic head for alignment disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic head for manufacturing an alignment disk used for positioning a magnetic head of a magnetic disk drive.

[Conventional technology]

In a magnetic disk drive, it is necessary to accurately determine the gap position of a magnetic head in order to ensure exchangeability with another device. As shown in FIG. 2, the cap position of the magnetic head is determined by a track position which is a radial distance from the disk center, an offset which is a circumferential distance from the disk center line, and an azimuth angle which is an inclination with respect to the disk center line. expressed.

To accurately determine the gap position, an optical method of enlarging the gap with a microscope or the like, measuring the distance from the reference position with a micrometer, etc., correcting errors and positioning,
There is a method using an alignment disk which electrically measures the output of a reference signal recorded in advance on the disk, corrects an error, and performs positioning. In recent years, the gap positioning method using an alignment disk, which is advantageous in accuracy and automation, has become mainstream.

A cat's eye signal for detecting a track position, an index burst signal for finding an offset amount, and an azimuth burst signal for finding an azimuth angle are recorded on the alignment disk.

As shown in FIG. 3 (a), the cat's eye signal is composed of an outer track signal 6a which is recorded on the outer track and the inner track of a specific track of the disc slightly eccentrically from the center O of the disc by Δι in advance, and an inner track. Side track signal 6b. As shown in FIG. 3 (b) which is an enlarged view of a portion A in FIG. 3 (a), the index burst signal 7a has a write gap of a magnetic head at a azimuth angle of 0 ° on the center of a specific track of the disk. , Are recorded at positions determined from the index signal. Similarly, azimuth burst signals 7b to 7e
Is recorded on the center of a specific track of the disk with azimuth angles θb, θc, θd, and θe, respectively. Also,
Each signal is written as an analog signal of an appropriate frequency, and the signal width is wider than the normal track width so that the output is stable even if there is a gap position shift.

When the alignment disk is read at the read gap 2 shown in FIGS. 3 (a) and 3 (b), FIG. 4 (a)
The signal output shown in FIG. 4 (b), which is an enlarged view of the portion B in FIG. 4 (a), is obtained.

With the cat's eye signal outputs 6a 'and 6b', the gap position in a specific track can be known by measuring the ratio of the two signal outputs. When the output ratio is 6b '>6a', the gap is shifted to the inner circumference side, when 6b '= 6a', the gap is in the correct position, and when 6b '<6a', the gap is the outer circumference side Represents a state of being shifted to. At the index burst signal output 7a ', the offset amount can be known by measuring the time T from the reference index signal. Azimuth burst signal output 7b '~ 7
In e ', the azimuth angle Da is obtained by the following equation (1) when the output values of the respective signals are A to D, respectively.

Here, K is an angle such that A = B or C = D.
FIG. 5 shows an example of azimuth burst signal output when K = 30 °. (A) shows a case of −30 °, (b) shows a case of ± 0 °, (c) shows a case of + 30 °, and (d) shows a case of an intermediate value between ± 0 ° and + 30 °. The expression (1) is basically obtained when θ in the following expression (2) for obtaining the azimuth loss changes.

Here, La is the azimuth loss (%), ω is the track width, θ is the head inclination (azimuth) (rad), and λ is the recording wavelength on the disk.

To position a magnetic head of a magnetic disk drive using an alignment disk, first roughly position the magnetic head at a specific track position using a cat's eye signal, and then use an index burst signal and an azimuth burst signal to set the offset amount and azimuth. The general procedure is to adjust the corners while finely adjusting the track position.

Next, a conventional example of an alignment disk manufacturing method will be described. It is assumed that the cat's eye signal has been written in advance by a device capable of rotating the disk eccentrically, and a detailed description thereof will be omitted. Here, a method of writing an index burst signal and an azimuth burst signal according to the present invention will be described.

FIG. 6 is an assembly plan view showing a main part of an apparatus for writing an index burst signal and an azimuth burst signal on an alignment disk, and FIG. 7 is a partial assembly plan view.

The magnetic head 11 is fixed to a rotating plate 8 rotatable on the base plate 14 about a rotating shaft 9 provided on the base plate 14 such that the center of the cap 12 coincides with the center of the rotating shaft 9. A dial gauge 13 is fixed to the base plate 14 via a dial gauge holder 16, and a measuring terminal 13 b is connected to a pin 1 provided on the rotating plate 8.
5 is in contact with the measuring pressure. Similarly base plate 1
The micro head 10 is fixed to 4 via a micro head holder 17, and the terminal portion 10a is pressed against the side surface of the rotating plate 8 by the tension coil spring 18 so as to prevent play.

Index burst signal to alignment disk
In writing 7a, the rotation angle of the rotating plate 8 is adjusted by the micro head 10 so that the azimuth angle of the gap 12 becomes 0 ° as shown in FIG. 7 (a). Next, as described above, the gap 12 is accurately positioned at a specific track position by the previously written cat's eye signal, and is written by the gap 12 based on an index signal generated by a spindle motor for rotating the disk.
The azimuth burst signals 7b to 7e are shown in FIGS.
As shown in the figure, the displacement amount of the pin 15 corresponding to each azimuth angle θb to θe is obtained in a triangular relation, and the obtained value is added to the reading 13a of the dial gauge when the azimuth angle is 0 °, and becomes 13a ′. The rotation angle of the rotating plate 8 is adjusted by the micro head 10 as described above, and based on the index signal,
Written by gap 12.

[Problems to be solved by the invention]

However, the index burst signal shown in FIG.
7a, and the conventional writing method of the azimuth burst signals 7b to 7e, not only requires an adjustment time for adjusting the azimuth angle of the gap 12 to the azimuth angle of each signal, but also the mechanical accuracy of the writing device, especially the gap If the center position accuracy of the center of 12 and the center of the rotating shaft 9 is not obtained, a significant error occurs in the azimuth angle. Also, the variation in the adjustment value of the azimuth angle becomes the variation in the signal accuracy as it is.

Therefore, an object of the present invention is to provide a magnetic head for an alignment disk that can write a high-accuracy signal in a short time.

[Means for solving the problem]

In the magnetic head for an alignment disk of the present invention, a plurality of gaps of a multi-gap magnetic head are arranged in a line along a circumference corresponding to the center of a specific track of the alignment disk, and the direction of each gap corresponds to an index burst signal and a corresponding burst signal. The azimuth burst signal is fixed in accordance with the azimuth angle, and the index signal and a plurality of azimuth burst signals are written in one writing.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a perspective view of the magnetic head of the present invention, and FIG.
FIG. 2B is a plan view showing a main part. Here, Side 3.5 of the 3.5-inch micro floppy disk 135 TPI specification will be described as an example.

The thin-film multi-gap magnetic head 1 has a single-layered magnetic substrate having a thickness of several tens of μm, a coil 23 wound in a plane using a photolithographic technique, a center ball 21 and a thin-film magnetic pole 22 forming a gap. A plurality is provided. Further, after the thin-film multi-gap magnetic head 1 is accurately positioned on the base 3 made of a ceramic substrate or the like, it is fixed by fixing means such as bonding, and is incorporated in an alignment disk manufacturing apparatus.

The thin-film multi-gap magnetic head 1 of the present invention has a gap 2a for an index burst signal and a center on a circumference corresponding to the center of the track 40 of the micro floppy disk, that is, on a circumference 5 of R = 32 mm. The gaps 2b to 2e for the azimuth burst signal are provided, and the signals written in the respective gaps have an azimuth angle of 0 ° and an azimuth angle θb to θe when read at the read gap position 2f of the magnetic disk device. It is set to be. The gap width is set to a track width of 0.1875 to stabilize the output even if there is a gap displacement as described above.
It is set much wider than mm.

The signal writing to the alignment disk
In 2a to 2e, an analog signal of an appropriate frequency is simultaneously written for a time corresponding to the burst width with reference to the index burst signal generated from the spindle motor.

[Effect of the invention]

In the magnetic head of the present invention, the plurality of gaps are precisely arranged at an azimuth angle suitable for writing an index burst signal and an azimuth burst signal. Therefore, as shown in the conventional example, there is no need to mechanically rotate the magnetic head having one gap, and the accuracy of the azimuth angle of each signal is improved, and the variation is significantly reduced. Further, a plurality of signals can be written at the same time, so that the time required to manufacture the alignment disk can be reduced and the cost can be significantly reduced.

[Brief description of the drawings]

1 (a) is a perspective view of the magnetic head of the present invention, FIG. 1 (b) is a plan view thereof, FIG. 2 is a plan view showing how to represent a gap position, and FIG. 3 (a) is on a disk. , FIG. 3 (b) is a partially enlarged view thereof, FIG. 4 (a) is a signal output of the alignment disk, FIG. 4 (b) is a partially enlarged view thereof, FIG. 5 ( a) to (d) are reproduction outputs of an azimuth burst signal, FIG. 6 is a plan view showing a main part of a conventional apparatus for writing an index burst signal and an azimuth burst signal, and FIGS. FIG. 4 is a diagram illustrating a state of a rotating plate when an index burst signal and an azimuth burst signal are written. 1 ... Thin-film multi-gap magnetic head, 2a-2f ... Magnetic gap, 3 ... Base, 4 ... Disk, 5 ... Specific track center circumference, 6a, 6b ... Cat eye signal, 6a ',
6b ': Cat's eye signal output, 7a: Index burst signal, 7a': Index burst signal output,
7b to 7e: azimuth burst signal, 7b 'to 7e': azimuth burst signal output, 21: center ball, 22 ...
Thin-film magnetic pole, 23 ... Coil.

Claims (1)

(57) [Scope of request for utility model registration] A magnetic head for writing at least an index burst signal and an azimuth burst signal on an alignment disk, wherein a plurality of write gaps each having a coil are arranged in a line along a write track, and the direction of the gap is adjusted. A magnetic head for an alignment disk, wherein the index burst signal and a plurality of azimuth burst signals are fixed in accordance with the azimuth angles of the index burst signal and the azimuth burst signal to be written.