JPH04301212A - Magnetic disk - Google Patents

Abstract

PURPOSE:To provide the magnetic disk which is high in production yield and eliminates the problem of a degradation in envelope waveform by decreasing its groove forming regions. CONSTITUTION:The magnetic disk D which is formed with grooves G for guiding the tracks of a magnetic head H on both sides of the concentrical or spiral tracks T is constituted by forming the grooves in a part of a circumferential or radial direction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to magnetic disks.

0002

2. Description of the Related Art As a method for improving the recording density of magnetic disks, guide grooves are provided between concentric or spiral tracks on magnetic disks, and magnetic heads are used for recording and/or recording.
Alternatively, a composite head has been proposed that is provided with a head for reproduction and an optical sensor or a pair of capacitance detection electrodes for tracking the guide groove. FIG. 8 is a schematic diagram showing a part of the magnetic disk enlarged and shown linearly. A guiding groove G is provided between each track T over the entire circumference and corresponding to all the tracks T.

FIG. 9 is a partial cross-sectional view of a magnetic head H and a magnetic disk D for explaining the conventional tracking method. The magnetic disk has a magnetic film formed on an aluminum substrate, has a groove G with a V-shaped cross section, and has a land portion as a recording track T. The magnetic head H includes a recording/reproducing head (not shown) and a pair of electrodes 11 and 12 arranged in parallel in the radial direction (horizontal direction in the drawing). The capacitance between the electrodes 11, 12 and the magnetic disk D is controlled by the distance between the electrodes 11, 12 and the conductive magnetic film. The electrode 11, relative to the radial center of the track T;
12 are located symmetrically, the capacitance between both electrodes 11, 12 and the magnetic disk D is equal; however, for example, if the magnetic head H shifts to the right in the figure, the capacitance of the electrode 12 on the right side increases. While the capacitance of the electrode 11 becomes smaller, the capacitance of the electrode 11 becomes larger. Track T tracking of the magnetic head H measures such electrostatic capacitance, and controls the radial position of the magnetic head H so that both capacitances are equal.

0004

[Problems to be Solved by the Invention] The groove G requires precision on the order of microns. Therefore, there is a problem that the manufacturing yield is poor. Furthermore, if the groove width changes in the circumferential direction, the magnetic head H will move slightly in the radial direction accordingly. Therefore, there is a problem that the envelope waveform of the reproduced signal deteriorates. The present invention has been made to solve these problems, and provides a magnetic disk that has a high manufacturing yield by reducing the groove forming area, and that does not have the problem of envelope waveform deterioration, and a magnetic disk device loaded with the same. The purpose is to provide.

[0005]

[Means for Solving the Problems] In the first invention, a guide groove is provided in a part of the circumferential direction. In the second invention, a guide groove is provided in a part of the radial direction.

[0006]

In the first aspect of the invention, tracking control of the magnetic head is performed in the portion where the groove is formed. In the second invention, one pair of the plurality of pairs of electrodes is involved in tracking the groove, thereby controlling the tracking of the magnetic head. Since the grooves are only formed in a portion of any magnetic disk, the manufacturing yield is improved accordingly, and the envelope waveform is also improved accordingly.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially enlarged view of a magnetic disk according to the first invention. The track T is formed around the entire circumference,
The guide groove G is formed in a part of the circumferential direction between the tracks T. Specifically, grooves G are provided over appropriate lengths at several specific angle ranges in the circumferential direction. It is appropriate that the formation area be 5 to 20% of the entire circumference. If it is less than 5%, a problem will arise in terms of tracking accuracy. Moreover, if it exceeds 20%, no significant effect in improving manufacturing yield will be obtained. The circumferential position of the groove G may differ depending on the radial position,
Alternatively, they may be arranged as shown in the figure.

FIG. 2 is a cross-sectional view showing the vicinity of the magnetic head H of a magnetic disk device in which the magnetic disk D is loaded. The comparison of capacitance between a pair of electrodes 11 and 12 is exactly the same as in the conventional device. Note that the groove shape may be V-shaped or rectangular. FIG. 3 is a schematic partially enlarged view of the second embodiment of the first invention. In this embodiment, a groove G is formed in each part of M sectors in one rotation. The groove forming area in each sector is preferably 5 to 20% as in the first embodiment.

In the case of the first invention as described above, tracking control is performed in the region where the groove G is formed, and the tracking control is not performed in the region where the groove is not formed. In the second embodiment, since each of these non-control periods is short, there is an advantage that there is less possibility of falling off track.

FIG. 4 shows a magnetic disk according to the second invention. In the second invention, as shown in the figure, grooves G are provided all around the circumference at a pitch of N tracks (three tracks in the figure). The magnetic disk D of the second invention requires a magnetic head in which N pairs of electrodes are arranged in parallel in the radial direction of the magnetic disk D (horizontal direction in the figure) as shown in FIG. In the illustrated state, the electrodes 11 and 12 are in the groove G.
, G, and recording or reproduction is being performed on a track T1 located between the central electrodes 13 and 14 at this time. Recording on a track T2 between the illustrated electrodes 11 and 12,
Alternatively, in the case of reproduction, the magnetic head H must be moved to the left so that the recording/reproducing head (not shown) is positioned above the track T2. Under this condition, tracking is performed in relation to the electrodes 13, 14 and the grooves G, G.

Conversely, when recording/reproducing on the track T3 located between the electrodes 15 and 16 in the illustrated state, the magnetic head H moves to the right and the recording/reproducing head moves to the track T3.
3. You need to come to the top. Under this condition, the electrodes 16,1
Tracking is performed in relation to 7 and the grooves G and G on the right side of the figure.

[0012] In the magnetic disk of the second invention, since tracking is performed on all tracks all around the circumference, the tracking accuracy is exactly the same as that of the conventional magnetic disk. FIG. 6 shows a second embodiment of the second invention. This has a groove G formed in a part of the radial direction and a part of the circumferential direction. For the same reason as described for the first invention, the grooves G are provided at several locations in the circumferential direction, and occupy 5 to 20% of the circumference. FIG. 7 shows a method for manufacturing a magnetic disk according to the present invention. A photoresist 22 is deposited on an aluminum substrate 21 whose surface has been plated with Ni--P (a).

Next, a mask 2 is formed according to the pattern for forming the grooves G.
(b) and develop the photoresist. Next, etching is performed by ion milling using the remaining photoresist 22 as a mask (c). Next, the photoresist 22 is removed by oxygen plasma treatment. The convex portions (lands) thus formed become tracks T, and the concave portions become grooves G. Furthermore, 0.3 μm thick Cr
A layer 24 and a 0.05 μm thick CoNiCr layer 25 are deposited in this order by a continuous sputtering method.

The manufacturing of the magnetic disk of the present invention is not limited to the above-mentioned method, but may also be performed by a stamper method, vapor deposition, or plating method. In addition, the magnetic disk has a recording layer CoNiCr layer 2.
A protective film and a lubricating film may be further formed on the film. Groove G
may be provided not only on the substrate as in the above-mentioned embodiments, but also on the recording layer, protective film, or lubricating film. Further, the guide groove tracking means is not limited to the capacitance detection type, but may be an optical sensor type.

[0015]

According to the present invention as described above, since the area in which the guide groove G is formed is smaller than that of the conventional method, the manufacturing yield is improved accordingly. As a result, the accuracy of the formed groove G increases, and the envelope waveform is improved.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged view of a magnetic disk of a first invention.

FIG. 2 is an explanatory diagram of a tracking method using a magnetic disk according to the first invention.

FIG. 3 is a schematic diagram of a second embodiment of the magnetic disk according to the first invention.

FIG. 4 is a partially enlarged view of a magnetic disk according to a second invention.

FIG. 5 is an explanatory diagram of a tracking method using a magnetic disk according to the second invention.

FIG. 6 is a schematic diagram of a second embodiment of a magnetic disk according to the second invention.

FIG. 7 is an explanatory diagram of a method for manufacturing a magnetic disk according to the present invention.

FIG. 8 is a partially enlarged view of a conventional magnetic disk.

FIG. 9 is an explanatory diagram of a conventional magnetic disk tracking method.

[Explanation of symbols]

D Magnetic disk G groove T track H Magnetic head 11 Electrode 12 Electrode 13 Electrode 14 Electrode 15 Electrode 16 Electrode

Claims (2)

[Claims] Claim 1: Concentric or spiral track (T)
Grooves (G) for track guidance of the magnetic head (H) on both sides of the
In the magnetic disk (D) in which the groove (
G) is a magnetic disk characterized in that it is formed in a part in the circumferential direction. Claim 2: Concentric or spiral track (T)
Grooves (G) for track guidance of the magnetic head (H) on both sides of the
In the magnetic disk (D) in which the groove (
G) is a magnetic disk characterized in that it is formed in a portion in the radial direction.