JPH0765358A - Magnetic recording medium and magnetic recorder - Google Patents

Abstract

PURPOSE:To enable tracking control with high accuracy at a low cost by detecting tracking signals with a magnetic head floating on a magnetic recording medium from the local magnetic field formed in a servo pit part. CONSTITUTION:A magnetic disk 1 has a magnetic film with which magnetic recording and reproducing of information are possible. This disk has a second region (RAM region) 40 where a user is able to magnetically record and reproduce the information and a first region (ROM region) 39 preformed with the magnetically reproducible information. The RAM region 40 and the ROM region 39 are provided with concentrical or spiral tracks. Data are recorded and reproduced and/or reproduced along these tracks. The preform pits are formable by etching a Cr film in such a case and the easy formation thereof with high accuracy is possible and, therefore, the formation of the preformatted magnetic recording medium at a low cost in a large quantity is possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording apparatus for magnetically recording and reproducing digital information while controlling the tracking of a magnetic head, and a magnetic recording medium used therefor.

[0002]

2. Description of the Related Art In a conventional magnetic recording medium in which digital information is recorded by a magnetic head, the eccentricity of the magnetic recording medium is made sufficiently small, the track width is made sufficiently wide, and the precision of the magnetic recording device mechanism is improved. Since the method of reducing the relative position error between the magnetic recording medium and the magnetic head is adopted, it is not necessary to perform tracking control. Further, in a magnetic recording medium for recording digital information, a magnetic film is sputtered on a disk substrate, for example, an aluminum substrate,
After the initial magnetization, a servo writer or a magnetic recording device is used to initialize one by one with a magnetic head.

[0003]

In order to make the recording track width of the magnetic recording medium narrower to achieve higher density, it is necessary to further improve the processing accuracy of the magnetic recording medium and the mechanical portion of the magnetic recording apparatus. However, as a result, the productivity of the recording medium (magnetic disk) is lowered, and the mechanical section of the magnetic recording apparatus is required to have high precision.
It becomes a very large-scale magnetic recording device.

In the past, fixed information peculiar to a computer could not be replica-formed in advance on a magnetic disk. Therefore, as personal computer software, software pre-recorded on a floppy disk was purchased. The complicated work of transferring the information from the floppy disk to the magnetic disk was necessary. As the scale of the software increases, the number of floppies increases to tens, which reduces the operability of the device and makes it difficult for the user to use. Moreover, in the magnetic disk medium, it is necessary to sputter a magnetic film on a disk substrate, for example, an aluminum substrate, to initially magnetize it, and then to initialize it by a magnetic head one by one with a servo writer or a magnetic recording device. It has been difficult to duplicate a large amount of disk media.

An object of the present invention is to perform highly accurate tracking control of a magnetic head by preforming servo pits that can be magnetically detected on a magnetic recording medium.
An object of the present invention is to provide a magnetic recording device that enables highly reliable high density recording.

It is another object of the present invention to preform servo pits and data pits that can be detected magnetically, thereby enabling highly accurate tracking control of the magnetic head and easily duplicating the magnetic recording medium. To provide.

[0007]

According to the present invention, a magnetic recording medium provided with preformed magnetically readable servo pits having magnetic characteristics different from those of a recording magnetic film is used. It is characterized in that a tracking signal or a synchronizing signal is magnetically detected from the magnetic flux distribution generated in the magnetic field, and the position of the magnetic head is servo-controlled to magnetically record / reproduce information.

In the magnetic recording medium of the present invention, meandering servo pits, track address pits, and data pits which can be magnetically read on the magnetic recording medium are preformed, and the pit portion is locally a recording magnetic film. Is a magnetic recording medium having a magnetic film structure having different magnetic characteristics, for example, a saturation magnetization reduced.

In the magnetic recording medium of the present invention, magnetically reproducible information is provided in the first area (R) in advance.
OM area) and a second area (RAM area) in which a user can magnetically record and reproduce information. The information in the first area (ROM area) can be duplicated even though it can be magnetically reproduced.
It is preferable to record fixed information peculiar to the device to be used such as software peculiar to the computer in the area.

According to one characteristic, the first region (R
The OM area) and the second area (RAM area) are angle-divided and mixed. Then, the first region (R
In the OM area, the magnetically reproducible information (ROM
Information) is preformed with a magnetic characteristic partially different from that of the recording magnetic film. In addition, the first area (ROM
In the area), a large number of magnetically reproducible servo marks preformed with magnetic characteristics partially different from those of the recording magnetic film are periodically provided along the track, and the magnetic marks are provided between the servo marks. Is provided with reproducible information (ROM information).

According to another feature, in the second area (RAM area) as well, magnetically reproducible servo marks preformed with magnetic characteristics partially different from those of the recording magnetic film are tracked. A large number of them are periodically provided along with the space between these servo marks to be a user information recording area.

[0012]

The magnetic recording apparatus of the present invention uses a magnetic recording medium in which servo pits whose magnetic characteristics are partially different from those of the recording magnetic film are preformed as marks for detecting tracking signals, and are formed in the servo pits. A magnetic head that floats over the magnetic recording medium from a local magnetic field generated by
Since the tracking signal is detected, the tracking signal can be detected with a high S / N ratio only by the magnetic head, and the size is small.

According to the recording medium of the present invention, servo marks (servo pits) having different magnetic characteristics from those of the recording magnetic film are preformed, and these preformed pits can be magnetically detected. The magnetic recording medium of the present invention can be duplicated, and the same magnetic recording medium can be produced in large quantities at low cost.

Further, according to the magnetic recording medium of the present invention, the first area (ROM area) in which magnetically reproducible information is provided in advance and the second area in which the user can magnetically record and reproduce information are provided. Since it has an area (RAM area), by storing fixed information peculiar to a device to be used such as software peculiar to a computer in this first area (ROM area), a user can create a floppy disk for each software program. From the magnetic recording medium to the magnetic recording medium. In addition, the information in the first area (ROM area) can be duplicated even though it can be magnetically reproduced, and a large number of magnetic recording media having the same pattern can be accurately manufactured.

Further, by providing a large number of servo marks in the first area (ROM area) and the second area (RAM area) periodically along, for example, concentric circles or spiral tracks, the servo marks can be formed. The generated magnetic flux distribution is magnetically detected by the magnetic head to obtain a tracking signal, and information is recorded in the second area (RAM area) or the first area (ROM area) while controlling the servo position of the magnetic head. Information in the area) can be read out.

[0016]

FIG. 1 shows a magnetic recording medium according to an embodiment of the present invention, showing tracking pits and clock pits provided on recording tracks formed on the recording surface of this magnetic recording medium. In FIG. 1A, a magnetic recording medium substrate 1 is made of glass, resin, or aluminum, and as shown in FIG. 1B, a number of tracking servo pits 3 are periodically arranged along tracks 2 and 2 '. , 3 ', 4,
4'is created by ion milling or reactive ion etching. In this way, as the servo mark, a pair of pits 3 and 4 (3 ', 4') distributed to the left and right with respect to the center line of the tracks 2, 2'is used. The tracking servo pit can be shared between the adjacent tracks 2 and 2 ', as shown in FIG. 1 (c). Also, FIG.
As shown in (d), the tracking pits may be formed wide so as to partially overlap each other when viewed in the circumferential direction. Reference numerals 35 and 35 'are clock pits provided along the center lines of the tracks 2 and 2', and these clock pits are also preformed by ion milling or reactive ion etching. Further, these preform pits 3, 4, 35, 3'4 ', 35' may be provided so as to be inclined with respect to the tracks 2, 2 ', as shown in FIG. Recording is performed with a tilted magnetic head. By doing so, crosstalk between the tracks 2 and 2'is eliminated, and the track pitch can be narrowed.

2A and 2B show servo pits 3, 3 ', 4, 4'or clock pits 35, 3 of the present invention.
5 shows a cross-sectional view of preform pits such as 5 ′ viewed along the disc circumferential direction, that is, the data recording direction.

FIG. 2A shows a diagram in which the magnetic head reproduces the preform pit portion. In the figure, 5 indicates a recording magnetic film formed on the substrate 1.

FIG. 2B shows the magnetic film structure near the preform pit portion 3. The structure of the magnetic film other than the preform pit portion 3 is, for example, 300 to 500 n as a base film on the aluminum (Al) or glass substrate 1.
A Cr film 32 having a thickness of m is formed by a sputtering method, and a ferromagnetic film 33 such as CoNiZr is formed on the Cr film 32 from 50 nm to 70 nm.
nm, and a protective film 34 of C or the like is further formed thereon by the sputtering method.

In the preform pit portion, the Cr base film 32 is formed.
Are partially removed, and the ferromagnetic film 33 and the protective film 3 are removed.
Only 4 are formed. After the film formation, the magnetic recording medium is initially magnetized uniformly by the magnet while rotating. The magnetization direction 6 coincides with the disk circumferential direction, that is, the data recording direction.

The Cr underlayer 32 has the effect of increasing the saturation magnetization Ms of the ferromagnetic film 33. Since there is no Cr underlayer 32 in the preform pit portion, the saturation magnetization at that location is small. When the recording magnetic film 5 is magnetized in one direction 6 by the initial magnetization, there is no leakage magnetic field at a place apart from the preform pit. However, in the preform pit portions such as the servo pits 3, 3 ', 4, 4', the saturation magnetization in that portion is smaller than that in the other portions, so that both walls 7, 8 of the preform pit are positive. A negative magnetic pole is formed, and as a result, a magnetic field is generated in the preform pit portion. The strength of this magnetic field is the largest at the center of the preform pit and symmetrical, and becomes smaller as it deviates from the center. In this way, the magnetic head 10 detects the magnetic flux 9 formed by the preform pit portions 3, 3 ′, 4, 4 ′, whereby a tracking signal can be obtained.

FIG. 3 shows the magnetic flux 11 passing through the magnetic coil 12 when the magnetic head 10 travels in the preform pit portion in the direction perpendicular to the data recording direction.
This magnetic flux 11 becomes large when the dimension of the magnetic head 10 in the direction perpendicular to the data recording direction is made substantially the same as the width of the preform pit in the direction perpendicular to the data recording direction, and a desired output signal is obtained. In FIG. 3, the magnetic flux 11 is symmetrical with respect to the center of the pit, and although the magnitude of the track deviation can be known from this, the direction of the track deviation cannot be detected.

FIG. 4 shows a recording medium according to an embodiment of the present invention. In order to detect the size and direction of the track deviation, a pair of servo pits 3 meandering with respect to the track center on the magnetic recording medium are used as servo marks. , 4 are formed. FIG. 4 shows a case where one magnetic head 10 can both record and reproduce data and detect a tracking signal. The track is divided into a servo area for detecting a tracking signal and a periodic signal and a data area for recording data, and a large number of tracks are provided periodically along the track. These servo area and data area are detected in a time division manner by one magnetic head that scans along the center line of the track. In the figure, the pit indicated by 35 is a preformed pit related to the clock and the access mark.
A magnetic film structure similar to that of the servo pit 3 in (b) is preformed on the substrate 1. Reference numeral 36 is a groove formed between the tracks to reduce crosstalk in reading data between the tracks. This groove 36
Is also preformed with the same structure as the servo pits 3 and 4. Reference numeral 37 indicates data magnetically recorded in the data area by the magnetic head. As described above, the preformed pits in the servo area are preformed by locally removing the magnetic characteristics different from those of the recording magnetic film, for example, by removing the underlayer film by etching, and the magnetic flux distribution generated in these servo areas is determined by the magnetic head. The sample is magnetically detected by the servo amplifier to obtain a tracking signal, and the magnetic head is servo-controlled based on the tracking signal, and desired RAM data (for example, code data) is stored in the user information recording area (data area) between the servo areas. 37 plays the track.
The magnetic film is a magnetic thin film for in-plane recording, and RAM data 3
A magnetic head 7 magnetically records and reproduces in-plane.

FIG. 5 is an embodiment of the present invention shown in FIG. 2 (b).
A method of producing a magnetic medium having no Cr underlayer in the pit portion shown in FIG. In FIG. 5, for example, a pattern of information to be provided in advance on the magnetic recording medium 1 with ultraviolet laser light on a chrome photomask, that is, magnetically reproducible servo pits 3, 4 and clock pits 35 provided in advance in the servo area, etc. Pattern of the preform pits and ROM data to be described later is recorded, then developed, the resist in the exposed area is dissolved, and the metal film is etched, the servo pits and clock pits shown in FIGS. As a result, the chrome mask 21 on which the pattern consisting of the rows of preform pits is recorded is obtained. Figure 5
In (a), a Cr thin film 32 is sputtered on an aluminum or glass disk substrate 1, a positive resist 22 is applied, and a metal mask 21 is brought into close contact with the disk substrate 1 on which the Cr film and the photoresist are formed to expose it. To do. Figure 5
In (b), after the positive resist 22 is exposed, the resist in the pit portion is dissolved by the development, but the other resist remains. In FIG. 5C, for example, the Cr thin film 32 in the pit portion where there is no resist is removed by etching by the reactive ion etching method. In FIG. 5D, the resist 22 in the unexposed portion on the disc is removed with an organic solvent, for example. In (e), C is formed on the pattern of the Cr thin film 32.
The ferromagnetic film 33 such as NiZr and the protective film 34 are uniformly formed by the sputtering method.

As described above, the magnetic recording medium shown in FIG. 5 can be used to form the magnetic recording medium having no Cr underlayer 32 only in the preform pit portion shown in FIG. 2B. The method of FIG. 5 can also form any pattern other than pits on the mask 21. For example, if a linear groove is formed, a linear groove having a magnetic characteristic different from that of the recording magnetic film is formed on the magnetic recording medium. It is possible to remodel.

In the above description, as shown in FIG. 4, it is assumed that the data area is a magnetic recording medium which can be freely recorded and erased by the magnetic head. Here, a disk having this function is named a disk having a RAM function. However, as a usage of the further expanded disk, the area 40 having the RAM function as shown in FIG. 6 is used.
And a ROM, that is, a disk form in which the read-only area 39 is mixed. With such a configuration, there is an advantage that the reproduction-only information and the rewritable information can be simultaneously accessed in a short time.

That is, the magnetic disk 1 has a magnetic film capable of magnetically recording and reproducing information, and can be magnetically reproduced with the second area (RAM area) 40 where the user can magnetically record and reproduce information. And a first area (ROM area) 39 on which various information is preformed. In FIG. 6, the RAM area 40 is provided on the outer peripheral side and the ROM area 39 is provided on the inner peripheral side. In FIG. 7, the RAM area 40 is provided on the outer peripheral side and the ROM area 39 is provided on the inner peripheral side, and the ROM areas 39 are angularly divided and mixed in the RAM area 40. The RAM area 40 and the ROM area 39 are provided with concentric or spiral tracks, and data is recorded / reproduced and / or reproduced along these tracks.

FIG. 8 shows data recording tracks in the ROM area 39. In FIG. 8, a data track is composed of a combination of a plurality of servo areas periodically provided along the track and a data area in which user information between the servo areas is recorded.

Preform pits 3, 4, in the servo area
The groove 35 between the tracks 35 and the tracks in the data area is the same as that shown in FIG. The pits 38 in the data area are formed on the disk substrate in the same manner as the preform pits 3, 4, 35 in the servo area in the ROM 39 area.

As described above, in the ROM area 39, the pits in the servo area and the ROM data 38 in the data area are both
As described above, the base film is locally removed by etching. A magnetic head magnetically samples and detects a magnetic flux distribution generated in these servo areas to obtain a tracking signal, and while controlling the servo position of the magnetic head based on the tracking signal, the ROM data 38 in the data area between the servo areas Play along the centerline of the track.

The ROM data 38 is only reproduced by the magnetic head and is not recorded by the magnetic head.

According to this embodiment, the ROM is used as the magnetic recording medium.
Not only can information be recorded in replicas at low cost,
Since ROM information and RAM information are mixed, when used in a device such as a personal computer, a software program or the like can be preliminarily formed in the magnetic recording medium as ROM information. Therefore, a floppy is used to copy the software to the magnetic recording medium. You can save time.

Further, by providing a large number of servo marks in advance in the first area (ROM area) and the second area (RAM area), the magnetic flux distribution generated in the servo marks is magnetically generated by the magnetic head. The information can be recorded / reproduced in the second area (RAM area) or the information in the first area (ROM area) can be read while detecting the servo position and controlling the servo position.

[0034]

According to the present invention, high-density recording is achieved by tracking the magnetic head with high accuracy. Further, since the preform pits can be formed by etching the Cr film and can be performed with high accuracy and easily, a large amount of preformatted magnetic recording media can be produced at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a magnetic recording medium of the present invention.

FIG. 2 is a diagram for explaining the operation principle of magnetic signal reproduction used in the present invention.

FIG. 3 is a diagram for explaining the operation principle of magnetic signal reproduction used in the present invention.

FIG. 4 is a diagram showing a data recording track.

FIG. 5 is a diagram for explaining an embodiment of a magnetic recording medium manufacturing method according to the present invention.

FIG. 6 is a diagram showing an example of a magnetic recording medium of the present invention.

FIG. 7 is a diagram showing an example of a magnetic recording medium of the present invention.

FIG. 8 is a diagram showing a data reproduction-only track in a ROM area.

Claims (7)

[Claims] 1. A magnetic recording medium having a ferromagnetic magnetic film on which magnetically readable information is recorded, wherein the magnetic property is different from that of the magnetic film, and a series of preformed servo pits or data pits or A magnetic recording medium in which linear grooves are provided in the track direction. 2. The magnetic recording medium according to claim 1, wherein the servo pits on the recording medium are wobbled in a direction perpendicular to the data recording direction or in a direction maintaining a constant angle. 3. The magnetic film is formed of a ferromagnetic magnetic film and a non-ferromagnetic underlayer film, and the preformed servo pits or data pits are formed by removing the non-ferromagnetic underlayer film. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is a magnetic recording medium. 4. The preformed servo pits or data pits are characterized in that the non-ferromagnetic underlayer film is not present, so that the saturation magnetization of the ferromagnetic film is small in that part. Item 3. The magnetic recording medium according to item 3. 5. The magnetic recording medium according to claim 3, wherein Cr is used as the underlayer film. 6. A tracking signal is detected by detecting a magnetic field generated in the preformed servo pit from the magnetic recording medium according to claim 1 by a magnetic head, and the tracking signal is detected by the tracking signal. A magnetic recording device for magnetically recording and reproducing information on a magnetic recording medium while controlling the position of the magnetic head. 7. The magnetic recording apparatus according to claim 6, wherein the width of the pit in the direction perpendicular to the data recording direction is about the same as the width of the magnetic head in the direction orthogonal to the track.