JPH0442433A - Thin film magnetic recording disk and thin film magnetic recording disk drive device - Google Patents

Abstract

PURPOSE:To perform recording/reproduction with high density by providing plural concentric circular grooves with specific depth set along a circumferential direction at a substrate, and providing magnetic film only in the grooves. CONSTITUTION:The plural concentric circular grooves with depth of 50-3,000Angstrom set along the circumferential direction are provided at the substrate, and the magnetic film 28 are provided only in the grooves. Therefore, the surface of the magnetic film 28 is formed at a position lower than a protrusive part where no magnetic film 28 is formed, and also, a thin film magnetic recording disk 1 always comes in contact with a slider plane 29 as moving the slider plane 29 of the magnetic head slidably on the protrusive part where no magnetic film 28 is formed when a recording/reproduction operation is performed. Thereby, no recording of a track position signal is required, and also, no dedicated servo head is required, and furthermore, overwrite characteristic can be improved and noise reduction can be attained, which enables the recording/ reproduction with high density to be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin film magnetic recording disk and a thin film magnetic recording disk drive device used for magnetic recording and reproduction of information.

BACKGROUND OF THE INVENTION In recent years, demands for higher capacity and faster processing speed for external storage devices for computers have been increasing, and thin-film magnetic recording disk drives are rapidly replacing the floppy magnetic recording disk drives that have been used for a long time. It is starting to be used.

A conventional thin film magnetic recording disk and a thin film magnetic recording disk drive device will be described below.

As shown in FIG. 7, a magnetic film 11 such as a magnetic metal alloy or a magnetic metal oxide is formed on a substrate such as an IV minium alloy 9 coated with a nickel-phosphorus film 1o, and a protective film 12 is formed on the substrate. is formed, and a lubricant 13 is further applied. On the surface of the substrate, many concentric grooves called textures are formed along the circumference. The radial pitch of the texture is very small compared to the track width of the magnetic head, and the width and depth of the grooves are not uniform, and the centerline average roughness Ra of the surface is generally about 60 to 200. be. A magnetic film 11 is formed on the substrate by a sputtering method, a vapor deposition method,
Since the film is usually formed to a thickness of 4,000 to 4,000 mm using the plating method, the film is uniformly and continuously formed on the surface of the substrate, regardless of the grooves in the texture. Carbon is often used as the protective film 12, and a lubricant 13 made of an organic material is applied to the outer surface.

As shown in FIG. 8, the thin film magnetic recording disk drive device is different from the floppy magnetic recording disk drive device.
The structure is such that several thin-film magnetic recording disks 1 are fixed to a motor spindle 4 inside the device and used while being isolated from the external environment.

2 is a magnetic head, 3 is a head arm, 5 is a motor, 6 is a carriage, 7 is a moving coil, and 8 is a permanent magnet.

As shown in FIGS. 9 and 10, the slider 19 of the magnetic head 2 includes an air bearing surface 14, a track portion 16, a gap 16, and a head core 18 provided with a coil 17. The arrow indicates the force pushing the slider 19;
The arrow C indicates the air flow, and the arrow C indicates the direction of movement of the substrate 20.

Reference numeral 21 indicates a magnetic film of the substrate 20.

The operation of the thin film magnetic recording disk drive device configured as described above will be described below.

The magnetic head 2 for recording and reproducing information is usually a magnetic head 2 called a floating head, which stands still in contact with the surface of the thin-film magnetic recording disk 1 when not in operation, but when started, the magnetic head 2 is in contact with the surface of the thin-film magnetic recording disk 1. When the magnetic recording disk 1 starts rotating, it reaches a floating state while sliding on the surface of the thin film magnetic recording disk 1, and during operation it reaches a floating state of 0.215 microns to 0.5 microns.
It flies without contacting the thin film magnetic recording disk 1 with a flying height of 4 microns.

Furthermore, when stopping, the rotational speed of the disk decreases and the disk slides to a stop, contrary to when starting.

Such a method is called a contact start nullop (CSS) method.

A floppy magnetic recording disk is made by coating a resin mixed with magnetic iron oxide to a thickness of several microns on a flexible planutic substrate several tens of microns thick.Furthermore, the resin is impregnated with a lubricant. Therefore, problems are unlikely to occur even if recording and reproducing operations are continued with the magnetic head constantly sliding on the disk surface. However, thin-film magnetic recording disks use metal magnetic materials with strong magnetism to increase recording capacity, and to improve recording and reproducing characteristics, the magnetic film must be thin. In order to increase the recording density and to speed up the processing speed, the relative speed of the thin film magnetic recording disk and the magnetic head during operation is significantly faster than that of a floppy magnetic recording disk. Therefore, it is easily damaged due to unexpected foreign matter getting caught during sliding or floating by the magnetic head. To avoid this phenomenon, when using thin-film magnetic recording disks, it is necessary to use a floating head that flies above the thin-film magnetic recording disk during recording and playback operations, and also to In order to reduce the coefficient of friction during contact, texture on the substrate, a protective film, a lubricant, etc. are required.

In the process of recording and reproducing, information is written in a plurality of discrete bands called concentric tracks, rather than using the entire area of the magnetic film on the disk surface. In thin film magnetic recording disks currently in use, the track width is about 20 microns, and the spacing between the tracks is about several microns. In this case, the width of the gap portion for generating the magnetic field of the corresponding magnetic head and obtaining the regenerative electromotive force is about 20 microns. During operation, the magnetic head floats on this track while the disk rotates at high speed, and when it is desired to record or reproduce other information, the magnetic head moves in the radial direction while floating, reaching other trunks. . Normally, in order to accurately detect the trunk position on a homogeneous and continuous magnetic film, data called servo information is written in advance at each track position, and a magnetic head called a servo head is used to specifically read out this data. It will be done.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, as the recording capacity increases, there is a need to reduce the flying height of the magnetic head in order to improve the efficiency of recording and reproduction. 1' 5
The flying height of microns to 0.4 microns is about to become 0.1 microns or less. In this case, as the flying height becomes lower, there is an increased chance that the magnetic head will collide with the disk while it is floating or moving in the radial direction of the disk to search for the track position, and furthermore, the magnetic head will fly during CSS. The problem is that the time it takes for the slide to stop and the time it takes for the slide to stop are longer, increasing the chances of damage to the protective film or the magnetic film.

It is still necessary to further reduce the center line average roughness R& of the surface of the substrate itself as the flying height of the magnetic head is lowered. The friction coefficient and the dynamic friction coefficient increase, causing problems such as adsorption phenomena and scraping of the carbon paste.

Furthermore, because the magnetic film of conventional thin-film magnetic recording disks is a homogeneous and continuous magnetic metal thin film, it is impossible to perfectly align the trunk positions when writing or reading information, even with the use of servosynutems. Yes, if you want to record new data on top of a previously recorded track,
Data may be recorded at a radial position on a thin film magnetic recording disk that is slightly offset from the track on which previous data was recorded. When the read head reads a signal from this track, it will also pick up previously recorded signals on the thin film magnetic recording disk at the edges of the track. For this reason, there is a problem that the characteristics normally called override characteristics deteriorate, and during the recording process, the leakage magnetic field from the recording head forms an undesirable magnetization pattern at the edge of the track that is unrelated to the original information, and during the reproduction process, the information is This magnetization pattern becomes noise when reading the data, causing an error.

In order to alleviate the above problems, a flat substrate is used, and magnetic films and non-magnetic films are alternately formed in the radial direction of the thin-film magnetic recording disk to form a plurality of concentric discrete magnetic film tracks. There is a method of manufacturing (for example, Japanese Patent Application Laid-Open No. 1-279
Publication No. 421). In this method, separation of the magnetic film is performed by lithography, and the regions between the tracks are filled with a nonmagnetic material different from that of the substrate.

Further, the usage in combination with a magnetic head is based on the premise that it is used in a conventional manner, and the magnetic head flies above the disk surface during operation. According to this method, override characteristics and noise reduction due to leakage magnetic fields are improved by using discrete magnetic film tracks, but C8S
There has been little improvement in the characteristics and flying characteristics of the magnetic head, and the manufacturing method, which involves etching the magnetic film using phosphorography and then filling the void with non-magnetic material, is extremely complicated. was.

The present invention solves the above-mentioned conventional problems. It is not necessary to record trunk position signals, and without using a dedicated servo head, it is possible to improve override characteristics and reduce noise p, and enables high-density recording and playback. An object of the present invention is to provide a highly reliable thin film magnetic recording disk and a thin film magnetic recording disk drive device.

Means for Solving the Problem In order to achieve this object, the thin film magnetic recording disk and thin film magnetic recording disk drive device of the present invention provide a substrate with a plurality of concentric circles along the circumferential direction having a depth of 60 to 3,000 people. A structure including a groove and a magnetic film only in the groove, and a substrate having a plurality of concentric grooves and a magnetic film track having a flat surface only in the groove, and a magnetic film track having a flat surface only in the groove. A thin film magnetic recording disk is used in which the surface of the substrate forming the area between the magnetic film tracks is at a height of 60 to 3000 mm above the surface of the magnetic film tracks, and the slider surface of the magnetic head for recording and reproduction is located between the magnetic film tracks. It has a configuration that slides over the area.

Function: With this configuration, the surface of the magnetic film of the thin-film magnetic recording disk is formed at a position lower than the surface of the protrusion on which no magnetic film is formed. Further, during the recording/reproducing operation, the slider surface of the magnetic head slides on the protrusion on which no magnetic film is formed, so that the thin-film magnetic recording disk and the slider section are always in contact with each other.

EXAMPLE A first example of the present invention will be described below with reference to the drawings. The shape of the plastic substrate injection molded using a mold with grooves made of polyetherimide has multiple concentric grooves in the circumferential direction, and the groove width is constant from the inner circumference to the outer circumference. is 5 microns, groove depth is 330O
The groove center pitch is 7 microns. The depth of the groove is determined so that the distance between the recording/reproducing head and the magnetic film formed in the groove is the maximum distance allowed to obtain designed electromagnetic conversion characteristics. That is, it is also possible to change the depth of the grooves between the inner and outer circumferential sides of the disk. In addition, the shape of the groove is vertical to the depth direction from the surface, and the bottom surface of the groove is finished as flat as possible. The side surfaces of the groove may not be the above-mentioned vertical surfaces, but may be diagonal surfaces that become narrower at the top in the height direction.

Further, it is desirable that the surface of the ridge portion between the grooves be as flat as possible.

As shown in FIG. 2, after a plastic substrate 22 is heated and sufficiently exposed, a metal thin film is sequentially formed using a spattering method. The metal thin film has a film thickness of 2000 mm.
Human chromium membrane23. A cobalt, nickel, and chromium alloy film 24 with a thickness of 60 degrees and a chromium film 25 with a thickness of 300 degrees are formed in this order. The above film attachment can be done by vapor deposition,
Metsuki.

You may also use CVD or the like.

Next, as shown in FIG. 3, the ridges on the surface of the substrate 22 are removed at high speed using a head made of ceramic and having grid-like notches in the slider section (Watzful head) to prevent floating even at high circumferential speeds. The parts are slid and the thin metal film on the surface of the ridges is scraped off and cleaned. To remove the metal thin film,
You can also rub it with wrapping tape that has abrasive particles attached. Then, as shown in FIG. 4, a carbon film 27 having a thickness of 200 mm is formed on the surface using the same sputtering method.

As shown in FIG. 6, a lubricant may be applied instead of the carbon film 26 to form a lubricant film 27 with a thickness of 20 mm.
As shown in the figure, a lubricant may be further applied on the carbon film 26 with a thickness of 200 mm to form a lubricant film 27 with a thickness of 20 mm. In this case, the distance between the surface of the gap portion of the magnetic head and the surface of the magnetic film track is 7208.

As described above, according to this embodiment, the substrate is provided with a plurality of concentric grooves having a depth of 60 to 3000 people along the circumferential direction,
By providing a magnetic film only in this groove, the sliding surface of the magnetic head always slides only on the protrusion of the thin-film magnetic recording disk, thereby eliminating damage to the magnetic film of the thin-film magnetic recording disk. I can do it.

A second embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a magnetic film 28 is formed in the groove portion of the thin-film magnetic recording disk 1, and is in contact with the slider portion 29 of the magnetic helad 2 via the protruding portion of the thin-film magnetic recording disk 1. There is. The width of the gap portion 3o of the magnetic head is designed to be wider than the width of the magnetic film 28 in the groove of the thin-film magnetic recording disk 1, that is, the width of the track. Both when the slider surface 29 and the gap portion 3o of the magnetic head 2 perform recording and reproducing operations while sliding in the circumferential direction of the thin-film magnetic recording disk 1, and when detecting the track position while sliding in the radial direction. The structure is such that it never comes into contact with the magnetic film 28.

Regarding magnetism, the magnetic field 2 has a three-rail shape, the two slider parts 29 are made of polyetherimide, and only the part where the magnetic flux flows between the gap parts 30 of the interrails is made of ferrite. Also, care was taken to ensure that the seven-point rail did not protrude beyond the slider portion 29.

The magnetic head may be a currently used floating head or a type of magnetic head for floppy disks. However, the material of the slider surface of the magnetic head should be determined by the material of the thin-film magnetic recording disk to be slid on, and if that material is plastic, the material of the slider surface of the magnetic head should also be made of plastic material. This is desirable because one side is not selectively worn away. The load applied to the magnetic head may be such that it can follow the fluctuations in the running direction of the protrusion of the thin-film magnetic recording disk, since the lifting force from the magnetic film surface acts on the magnetic head during running.

As described above, according to this embodiment, the substrate has a plurality of concentric grooves, the magnetic film tracks are formed only in the grooves, and the surface forming the area between the magnetic film tracks is Using a thin-film magnetic recording disk that is higher than the surface, the slider surface of the magnetic head slides in the area between the magnetic film tracks, so that during recording and reproducing operations, thin-film magnetic recording without a magnetic film is formed. Since the slider surface of the magnetic head slides on the protrusion of the recording disk at high speed and can be used in a state where the thin film magnetic recording disk and the slider surface are always in contact with each other, it is possible to reduce the Even when levitating, the film is not damaged, and information can be recorded and reproduced stably and efficiently at high density. In addition, since the contact area of the magnetic head with the disk when it is stationary and when it is sliding is small, the coefficient of static friction and the coefficient of dynamic friction are small, and adhesion phenomena and destruction of the surface of the thin-film magnetic recording disk are less likely to occur. Furthermore, since the magnetic head always slides in contact with the protrusion of the thin-film magnetic recording disk, no sudden impact force is generated due to biting of dust or the like. Furthermore, since the gap width of the magnetic head is wider than the magnetic film track width of the disk, no track deviation occurs during recording and reproduction, and therefore, override characteristics are improved.

Furthermore, since the leakage magnetic field from the recording head does not reach the edge of the track, noise caused by this can also be reduced.

Effects of the Invention As is clear from the description of the embodiments above, the present invention has a configuration in which a substrate is provided with concentric grooves and a magnetic film is provided only in the grooves, and a flat surface is provided in the concentric grooves of the substrate. Using a thin film magnetic recording disk in which magnetic film tracks are formed and the surface of the substrate in the area between the magnetic film tracks is higher than the surface of the magnetic film tracks, the slider surface of the magnetic head is moved between the magnetic film tracks. This structure prevents damage to the magnetic film, eliminates the need to record track position signals, eliminates the need for a dedicated servo head, and improves override characteristics and reduces noise. Therefore, it is possible to realize an excellent thin film magnetic recording disk and a thin film magnetic recording disk drive device that can perform high-density recording and reproduction.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing the positional relationship between the magnetic head and the thin film magnetic recording disk of a thin film magnetic recording disk drive device according to a second embodiment of the present invention, and FIGS. FIG. 7 is a partial cross-sectional view of a conventional thin-film magnetic recording disk; Fig. 8 is a configuration diagram of a conventional thin film magnetic recording disk drive device, Fig. 9 is a perspective view showing the configuration of the same floating head, and Fig. 10 shows the operating state of the slider of the same magnetic head and the thin film magnetic recording disk. FIG. 1... Thin film magnetic recording disk, 2...
Magnetic head, 16...Track section, 18...
...Head core, 19...Slider, 22.
...Substrate, 23.25...Chromium film, 24...Cobalt-nickel-chromium alloy film, 26...Carbon film, 27...・
Lubricating film, 28...Magnetic film, 29...Slider surface, 30...Gap portion. Name of agent: Patent attorney Shigetaka Awano #1 or 1 personζ
) Aji Ward

Claims (2)

[Claims] (1) The depth of multiple concentric circles along the circumferential direction of the board is 6
A thin film magnetic recording disk comprising grooves of 0 to 3000 Å and a magnetic film only within the grooves. (2) The substrate has a plurality of concentric grooves, a magnetic film track having a flat surface is formed in the groove, and the surface of the substrate forming the area between the magnetic film tracks is the surface of the magnetic film track. A thin film magnetic recording disk drive device using a thin film magnetic recording disk having a height of 50 to 3000 Å, in which a slider surface of a magnetic head for recording and reproduction slides in an area between the magnetic film tracks.