JPH04278216A - Magnetic disk apparatus - Google Patents

Abstract

PURPOSE:To obtain good envelope waveform and realize tracking control which is resistive to disturbance and ensures high accuracy in a magnetic disk apparatus which enables high density recording. CONSTITUTION:In a magnetic disk apparatus which realizes tracking control by detecting an electrostatic capacitance between an electrode part 2 and a magnetic disk 5 using a composite head 3 integrally structuring a magnetic head l and the electrode part 2 and a magnetic disk 5 having a guide groove 4, the pit regions in different pit patterns of the adjacent guide grooves 4 are formed in a plurality of desired areas on the circumference of the magnetic disk 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device capable of high-density recording. 2. Description of the Related Art Magnetic disk drives used as external storage devices for computer systems are required to be smaller and have larger capacities, and higher recording densities are being promoted. With this increase in recording density, there is a demand for reduction in crosstalk and improvement in tracking accuracy.

0002

[Prior Art] In order to make magnetic disk drives more compact and larger in capacity, advances are being made in terms of both linear recording density and track density. Efforts are being made to make the layers thinner and to increase the coercive force. Furthermore, although ferrite heads were mainly used as magnetic heads, thin film heads that can realize fine structures with high precision are now being used. In addition, in order to improve track density, a magnetic disk with guide grooves formed between recording tracks has been proposed, and by combining this magnetic disk with a composite head that integrates a magnetic head and electrodes, A configuration has been proposed in which tracking is performed by detecting the capacitance between the magnetic disk and the magnetic disk.

FIG. 9 is an explanatory diagram of a conventional example in which the aforementioned guide grooves are provided, in which concentric or spiral guide grooves 66 are formed on both sides of a recording track 67 of a magnetic disk 65. This guide groove 66 is shown as a schematic cross section on the right side.
Although the cross-section is triangular, other cross-sectional shapes are also possible. Using this magnetic disk 65 and a composite head 64 consisting of a magnetic head section 61 and electrode sections 62 and 63, the composite head 64 is constructed such that the capacitances of the two electrode sections 62 and 63 are approximately equal. By positioning the
The magnetic head section 61 is positioned approximately at the center of the recording track 67, and this magnetic head section 61 magnetically performs recording or reproduction on the recording track 67. Such a configuration is described, for example, in Japanese Patent Application Laid-Open No. 63-1836.
This is shown in Publication No. 05.

FIG. 10 is an explanatory diagram of a conventional example in which guide grooves are provided by pits, and a composite head 74 has a magnetic head portion made up of a yoke 71 and a coil 72, and a magnetic thin film 73 made of permalloy or the like. and an electrode section, and is attached to an actuator 79 via a cantilever 78. Further, the magnetic disk 75 is made of carbon, for example, on a substrate made of conductive polyester or the like mixed with fine carbon powder or the like.
Coated with a magnetic layer such as o-Cr, pit rows 76 are formed on both sides of a concentric or spiral recording track 77, and the pit rows 76 of adjacent pit rows 76 are arranged at different pitches to reduce static electricity caused by the electrode portion. When capacitance detection is performed, a positioning error component can be obtained by comparing the levels of frequency components. Such a configuration is, for example, disclosed in Japanese Patent Publication No. 1-404.
This is shown in Publication No. 02. Note that this publication describes the case where perpendicular magnetic recording is performed.

[0005]

Problems to be Solved by the Invention In the conventional example shown in FIG.
This is very effective in eliminating writing blur and reducing crosstalk, where the magnetic recording area spreads relative to adjacent tracks. However, the capacitance due to the electrode parts 62 and 63 is will be detected and therefore
This has the disadvantage that the influence of noise and drift increases, resulting in tracking errors.

Furthermore, in the conventional example shown in FIG. 10, since the periods of adjacent pit rows 76 are different, the change in capacitance due to the electrode portion of the composite head 74 corresponds to the period of the pit rows 76. By extracting the frequency components and comparing the levels, tracking control can be performed, which has the advantage of being resistant to external disturbances, but since the magnetic layer is continuous in the radial direction between pits, crosstalk and reproduction This causes the problem of waveform deterioration. SUMMARY OF THE INVENTION An object of the present invention is to enable highly accurate tracking control that can obtain a good envelope waveform and is resistant to external disturbances.

[0007]

[Means for Solving the Problems] The magnetic disk device of the present invention will be described with reference to FIG. A magnetic disk device comprising a magnetic disk 5 having a guide groove 4 consisting of a magnetic disk 5 and detecting the capacitance between the electrode part 2 of the composite head 3 and the magnetic disk 5 to perform tracking control of the composite head 3. In this, the guide grooves 4 are formed from pit areas formed at an arbitrary number of locations on the circumference of the magnetic disk 5, and in which pit patterns of adjacent guide grooves 4 in the radial direction are formed to be different. It is something.

Further, the guide groove 4 is constituted by pit areas formed at an arbitrary number of locations on the circumference of the magnetic disk 5, and continuous groove areas in which continuous grooves 6 are formed between the pit areas. be able to.

Further, the circumference of the magnetic disk 5 can be divided into a plurality of sectors, and the pit area of the guide groove 4 can be formed in a part of each sector. Moreover, a continuous groove area consisting of continuous grooves 6 can be formed between the pit areas.

Further, the electrode portions 2 of the composite head 3 are provided corresponding to a plurality of tracks along the radial direction of the magnetic disk 5,
The pit area of the guide groove 4 of the magnetic disk 5 can be formed for every track of the number of electrode parts 2. Further, a continuous groove region consisting of continuous grooves 6 can also be formed between pit regions.

[0011]

[Operation] The guide grooves 4 formed in the magnetic disk 5 are formed at any number of locations on the circumference of the magnetic disk 5, and since the patterns of radially adjacent pit rows are different, the electrode portions 4
When detecting capacitance using
Highly accurate tracking control that is resistant to external disturbances can be performed. Furthermore, by using the area other than the pit area as the data recording area, it is possible to improve demodulation errors due to deterioration of the envelope waveform.

Furthermore, by forming a continuous groove area between pit areas and using the recording track of this continuous groove area as a data recording area, it is possible to improve the envelope waveform and reduce crosstalk.

[0013] Furthermore, in a configuration in which a pit area is formed in a part of the sector, control similar to that of a normal sector servo is possible, and this pit area can be about 5 to 20% of the sector, and the rest can be It can be used as a data recording area.

[0014] Also, N electrode portions 2 are provided corresponding to N tracks,
When a pit area of the guide groove 4 is formed every N tracks of the magnetic disk 5, there are (N-1) tracks in which a pit area is not formed on one or both sides, and data is recorded over the entire circumference of the track. It can be a region.

[0015]

[Embodiment] FIG. 1 is an explanatory diagram of a first embodiment of the present invention, in which a composite head 3 integrally comprising a magnetic head section 1 and an electrode section 2 is attached to a head arm (not shown). ,
This head arm is moved by an actuator to position the composite head 3 on a predetermined track on the magnetic disk 5. The magnetic disk 5 has rows of short pits 4a and rows of long pits 4b alternately formed in the radial direction at an arbitrary number of locations on the circumference to form pit regions of the guide groove 4, and between these pit regions. A continuous groove region consisting of continuous grooves 6 on the circumference is formed.

The frequency of the change in capacitance between the electrode portion 2 of the composite head 3 and the magnetic disk 5 is determined by
If f1 is defined as f1, and f2 is defined as pit 4b, then in the illustrated case, the relationship is f1>f2. Therefore, frequencies f1, f
By separating the two detection signals and controlling the positioning of the composite head 3 so that the levels of the signals of each frequency f1 and f2 are equal, the magnetic head section 1 can be positioned at the center of the track. Further, pit areas can be formed at multiple locations on the circumference, and if the track area excluding the track in the pit area is used as a data recording area, adjacent tracks are magnetically separated by the grooves 6. There is no writing blur and crosstalk can be reduced. Note that data can also be recorded in the pit area, and in this embodiment, it is desirable to record data of relatively low importance.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention, in which the same reference numerals as in FIG. This is the control section. This embodiment shows a case where grooves 6 are not formed between pit areas, and a cross section of the main part of the magnetic disk 5 along the line A-B between the pits 4a, 4b and the track 7 is shown below.

Furthermore, the bandpass filter 11 has frequencies f1,
The bandpass filter 12 has a pass band of frequency f2, and detects the capacitance between the electrode section 2 and the magnetic disk 5 by the capacitance detection section 10, and detects the frequency component of f1 by the pattern of the pits 4a. Band pass filter 11 for the signal
The signal of the frequency component of f2 due to the pattern of the pits 4b is extracted by the bandpass filter 12,
The comparison control unit 13 compares the levels of the signals at frequencies f1 and f2, and controls an actuator (not shown) so that the signal levels at frequencies f1 and f2 become equal. As a result, the magnetic head section 2 of the composite head 3
can be positioned at the center of the track 7.

FIG. 3 is an explanatory diagram of a third embodiment of the present invention, in which one round of the magnetic disk is divided into n sectors, and
A pit area is formed in a part of each sector 1 to sector n, and there is a row of short pits 4a that can detect a signal of frequency f1 according to a change in capacitance, and a row of long pits 4b that can detect a signal of frequency f2. are formed alternately in the radial direction, as in each of the above-described embodiments. This pit area can be used as a sector servo area, and the other areas can be used as data recording areas. In that case, due to tracking accuracy,
It is practical to set the pit area to 5 to 20% per sector.

FIG. 4 is an explanatory diagram of a fourth embodiment of the present invention, and like the third embodiment described above, sectors 1 to n
A pit region is formed in a part of the pit region, and a continuous groove region consisting of continuous grooves 6 is further formed between each pit region. In this embodiment, since the data recording area in each sector 1 to sector n is magnetically separated from adjacent tracks by the groove 6, crosstalk can be reduced.

FIG. 5 is an explanatory diagram of a fifth embodiment of the present invention, in which a plurality of electrode sections of a composite head are provided corresponding to a plurality of tracks, and electrode sections corresponding to tracks 7-1 to 7-4 are provided. A case is shown in which four electrode sections 2-1 to 2-4 are provided. Also, a set of a row of short pits 4a that can detect a signal of frequency f1 according to a change in capacitance and a row of long pits 4b that can detect a signal of frequency f2 is arranged in tracks 7-1, every four tracks.
7-5, 7-9, . . . In addition,
The number of electrode parts can be any number of three or more.

Furthermore, when using a composite head in which a magnetic head section is provided at the position of the electrode section 2-1, when positioning on the track 7-1, the electrode section 2-1 and the pits 4a on both sides of the track 7-1 are used. , 4b, it is possible to obtain signals with frequencies f1 and f2 according to the change in capacitance between
The positioning of the magnetic head section of the composite head can be controlled so that the signal levels of f1 and f2 are approximately equal. Also, when positioning on the track 7-2, the electrode part 2-
4 can obtain signals of frequencies f1 and f2 according to changes in capacitance between pits 4a and 4b on both sides of track 7-5, so the magnetic head section of the composite head can be moved to track 7-2. The positioning can be controlled at the center. Similarly, when positioning on track 7-3, electrode part 2-
3 can obtain signals of frequencies f1 and f2 according to changes in capacitance between pits 4a and 4b on both sides of track 7-5. can be positioned at the center of

In a composite head, it is difficult to provide a plurality of magnetic head sections along the radial direction of the magnetic disk, even if a thin film head configuration is used, due to the width of the thin film coil. Also, except for the pit areas of tracks 7-1, 7-5, 7-9, etc., all can be used as data recording areas, so for example, tracks 7-2, The entire circumferences of 7-3 and 7-4 can be used as data recording areas. Therefore, highly accurate tracking control can be performed and storage capacity can be increased.

FIG. 6 is an explanatory diagram of a sixth embodiment of the present invention, and the same reference numerals as in FIG. 5 indicate the same parts. This example is
This corresponds to the case where grooves 6 are formed in the fifth embodiment, and the tracks 7-1, 7-5, . . . are formed between the grooves 6.
It is possible to reduce crosstalk in

FIG. 7 is an explanatory diagram of a seventh embodiment of the present invention, and the same reference numerals as in FIGS. 5 and 6 indicate the same parts. In this embodiment, continuous grooves 8 are formed on both sides of the track 7-3 in the sixth embodiment. In this embodiment, the continuous groove 8 is not used for tracking control, but has the advantage of preventing writing bleeding in magnetic recording and reducing crosstalk.

FIG. 8 is an explanatory diagram of the manufacturing process of an embodiment of the present invention, showing a case including the steps (a) to (e). First, as shown in (a), Ni-P plated aluminum is A photoresist 22 with a thickness of 1 μm is coated on the substrate 21 of the photoresist 21 .

Next, as shown in (b), the photoresist 22 is exposed to light using the exposure mask 23 having the pattern of the pits 4a and 4b described above, and a resist pattern is formed by a development process. For example, the exposure mask 23
The light transmitting portion 24 is formed in a pattern of pits 4a, 4b or grooves 6, 8, and the photoresist 2 is formed by a development process.
2, the pattern of the light shielding portion 25 of the exposure mask 23 remains.

Next, as shown in (c), using the resist pattern 26 of the photoresist 22 remaining after exposure and development as a mask, the substrate 2 is milled by ion milling.
Etch 1.

Next, as shown in (d), when the resist mask is removed by oxygen plasma treatment, the pits 4a,
4b, a concave portion 27 forming grooves 6 and 8, and a convex portion 28 forming a track.

Next, as shown in (e), a magnetic layer 30 is formed. (f) shows an enlarged view of the structure of the magnetic layer 30, in which, for example, a Cr layer with a thickness of 0.3 μm is formed on the substrate 21.
A CoNiCr recording layer 32 having a thickness of 0.05 μm is formed thereon. This base layer 3
1 and the recording layer 32 can be formed by a continuous sputtering method. Therefore, the area of the substrate 21 corresponding to the convex part 28 becomes a track, and the area corresponding to the concave part 27 becomes a pit area or a continuous groove area.

The depths of the pits 4a, 4b and the grooves 6, 8 are as follows:
In order to increase the S/N of the signal of the frequency component according to the capacitance change, it is desirable to set the flying height to be greater than or equal to the flying height of the composite head 3, and in order to reduce crosstalk, (e) in FIG.
As shown in (f), it is desirable that the thickness be equal to or greater than the thickness of the recording layer 32. Also, pits 4 are formed on the substrate 21 by a stamper method or the like.
It is also possible to form the recesses 27 corresponding to the grooves 6 and 8, and the magnetic layer 30 can also be formed by a vapor deposition method, a plating method, or the like. A protective layer can also be provided.

Furthermore, since the rows of pits 4a and 4b are used to obtain signals of different frequency components through capacitance detection, the pits 4a and 4b can be made to have the same size and differ only in pitch. . Moreover, it is also possible to use not only two types of patterns but also more patterns. For example, it is possible to obtain signals of frequencies f1 and f2 by capacitance detection for a certain track, and to obtain signals of frequencies f2 and f3 for adjacent tracks. In this case, the bandpass filters 11 and 12 with frequencies f1 and f2 in FIG. 2, and a bandpass filter with frequency f3 are provided, and the frequency f
1 and f2 as well as frequency f1 and f3.
This means that a configuration for comparing the levels of the signals at frequencies f2 and f3 and comparing the levels of the signals at frequencies f2 and f3 is added. Mata pit 4a
, 4b and the grooves 6, 8 may be formed in the base layer 31, the magnetic layer 32, etc. by photolithography technology, etc., instead of being formed by the recess 27 of the substrate 21.

[0033]

As explained above, according to the present invention, pit areas are formed in an arbitrary number of locations on the circumference of the magnetic disk 5, in which the pit patterns of the radially adjacent guide grooves 4 are different. Since signals of frequencies f1 and f2 are obtained by detecting the capacitance between the electrode part 2 of the composite head 3 and the magnetic disk 5, highly accurate tracking control that is resistant to external disturbances is possible, and it is also compatible with the sector servo type. Similarly, since it is possible to obtain a good envelope waveform by using the area other than the pit area for obtaining tracking information as the data recording area, it has the advantage of increasing capacity due to high track density and high linear recording density. be.

Furthermore, by forming a continuous groove region other than the pit region, high tracking accuracy can be obtained and crosstalk can be reduced, making it easy to increase the track density.

Furthermore, by providing a plurality of electrode portions in the composite head 3, it is sufficient to provide pit areas for each of a plurality of tracks on the magnetic disk 5, and the data recording area can be increased. Therefore, it is possible to increase the capacity.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram of a fifth embodiment of the present invention.

FIG. 6 is an explanatory diagram of a sixth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a seventh embodiment of the present invention.

FIG. 8 is an explanatory diagram of the manufacturing process of an embodiment of the present invention.

FIG. 9 is an explanatory diagram of a conventional example.

FIG. 10 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 Magnetic head section 2　　　Electrode part 3. Composite head 4 Guide groove 4a Pit 4b Pit 5 Magnetic disk 6 Groove

Claims (4)

[Claims] [Claim 1] A magnetic head section (1) for magnetic recording and reproduction.
A composite head (3) integrally constitutes a capacitance detection electrode part (2) and a guide groove (3) consisting of a plurality of pits.
a magnetic disk (5) having a magnetic disk (5) having a magnetic disk (4);
) by detecting the capacitance between the composite head (3) and
In a magnetic disk device that performs tracking control,
The guide grooves (4) are formed at an arbitrary number of locations on the circumference of the magnetic disk (5), and the pits of radially adjacent guide grooves (4) are formed in different patterns. A magnetic disk device characterized by comprising a pit area. 2. The guide groove (4) includes the pit area formed at an arbitrary number of locations on the circumference of the magnetic disk (5), and a continuous groove (6) formed between the pit areas. 2. The magnetic disk device according to claim 1, further comprising a continuous groove region. 3. The circumference of the magnetic disk (5) is divided into a plurality of sectors, and the guide groove (4) is formed in a part of the sector.
3. The magnetic disk device according to claim 1, further comprising a pit area formed therein. 4. The electrode portion (2) of the composite head (3) is provided corresponding to a plurality of recording tracks along the radial direction of the magnetic disk (5), and
3. The magnetic disk device according to claim 1, wherein the pit areas of the guide grooves (4) are formed for every recording track of the number of the electrode parts (2).