JP3424075B2 - Method for manufacturing magnetic recording medium, magnetizing head for manufacturing magnetic recording medium, and magnetic transfer device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium manufacturing method, and more particularly to a technique for recording a predetermined information signal on a magnetic recording medium used in a magnetic recording / reproducing apparatus. The present invention also relates to a magnetizing head used in a method of manufacturing a magnetic recording medium .

[0002]

2. Description of the Related Art In recent years, a magnetic recording / reproducing apparatus tends to have a high recording density in order to realize a small size and a large capacity.
In the field of hard disk drives, which are typical magnetic storage devices, the surface recording density has already reached 10 Gbit / in.
Equipment exceeding ² (15.5 Mbit / mm ² ) has been commercialized, and currently 20 Gbit / in ² (31.0
It is recognized that the technological progress is so rapid that the practical application of the areal recording density exceeding Mbit / mm ² ) is discussed.

As a technical background for enabling such a high recording density, there is a great improvement in the linear recording density due to the improvement of the medium performance, the head / disk interface performance, and the advent of a new signal processing method such as partial response. It is a factor. However, recently, the increasing tendency of the track density greatly exceeds the increasing tendency of the linear recording density, which is a main factor for improving the areal recording density. This is based on the contribution of the practical application of the magnetoresistive element type head, which is far superior to the conventional induction type magnetic head in reproducing output performance. At present, the practical application of the magnetoresistive element type head makes it possible to reproduce a track width signal of only a few μm or less with good S / N. On the other hand, it is expected that the track pitch will reach the submicron region in the near future with further improvement in head performance.

In order for the head to accurately scan such a narrow track and reproduce the signal with good S / N, the head tracking servo technique plays an important role. Regarding such tracking servo technology, in the present hard disk drive, a tracking servo signal, an address information signal, a reproduction clock signal, etc. are recorded at a constant angular interval in one round of the disk, that is, in an angle of 360 degrees. Area (below,
Referred to as preformat). By reproducing these signals at regular intervals, the magnetic head can accurately scan the track while confirming and correcting the position of the head.

Since the tracking servo signal, address information signal, reproduction clock signal and the like described above serve as reference signals for the head to scan the track accurately, accurate positioning accuracy is ensured during recording. Required. In a current hard disk drive, after the disk is incorporated into the drive, preformat recording is performed by a magnetic head whose position is strictly controlled using a dedicated servo recording device.

Conventionally, the following problems have been encountered in preformat recording of servo signals, address information signals, and reproduction clock signals by a magnetic head using the dedicated servo recording device as described above.

First of all, recording by a magnetic head is basically line recording based on relative movement between the head and the medium. For this reason, in the above method of performing recording while strictly controlling the position of the magnetic head using the dedicated servo recording device, it takes a lot of time for preformat recording, and the dedicated servo recording device is considerably expensive. Due to this, the cost becomes very high.

Secondly, due to the spacing between the head and the medium and the spread of the recording magnetic field due to the pole shape of the recording head,
There is a problem in that the transition of magnetization at the end of the preformat-recorded track lacks steepness. The current tracking servo technology detects the position of the head based on the amount of change in the reproduction output when the head scans off the track. Therefore, the pre-format-recorded signal track is not only excellent in S / N when the head accurately scans the track as when reproducing the data information signal recorded between the servo areas, but also in the head. It is required that the reproduction output change amount when scanning off the track, that is, the off-track characteristic is steep. The above problem is contrary to this requirement, and makes it difficult to realize an accurate tracking servo technique for submicron track recording in the future.

Therefore, the following method has been proposed as a means for solving the problems of the conventional preformat recording using the magnetic head.

For example, in Japanese Unexamined Patent Publication No. 10-40544, a master information carrier is formed by forming a magnetic portion made of a ferromagnetic material in a pattern shape corresponding to an information signal on the surface of a substrate, and the surface of this master information carrier. To the surface of a sheet-shaped or disk-shaped magnetic recording medium on which a ferromagnetic thin film or a ferromagnetic powder coating layer is formed, and by applying a predetermined magnetic field, a pattern corresponding to the information signal formed on the master information carrier. A method of recording a shaped magnetization pattern on a magnetic recording medium is disclosed.

In the structure disclosed in Japanese Patent Laid-Open No. 10-40544, the recording magnetic field generated from the ferromagnetic thin film on the surface of the master information carrier magnetized in one direction causes
A magnetic pattern corresponding to the ferromagnetic thin film pattern of the master information carrier is transferred and recorded (magnetic transfer) on the magnetic recording medium. That is, by forming a ferromagnetic thin film pattern corresponding to a tracking servo signal, an address information signal, a reproduction clock signal, etc. on the surface of the master information carrier by a photolithography technique or the like, a preparatory pattern corresponding to these is formed on the magnetic recording medium. Format recording can be performed.

While the conventional recording by the magnetic head is basically the dynamic line recording based on the relative movement between the head and the medium, the feature of the above configuration is that the relative movement between the master information carrier and the medium is involved. It is not a static face recording. Due to such characteristics, Japanese Patent Laid-Open No. 10-40544
The technique disclosed in the publication can exhibit the following extremely effective effects with respect to the above-mentioned problems in preformat recording.

First, since it is surface recording, the time required for preformat recording is much shorter than that of the conventional recording method using a magnetic head. Further, an expensive servo recording device for performing recording while strictly controlling the position of the magnetic head is unnecessary. Therefore, the productivity in preformat recording can be significantly improved and the production cost can be reduced.

Secondly, since the master information carrier and the magnetic recording medium are static recording without relative movement, the surface of the master information carrier and the surface of the magnetic recording medium are brought into close contact with each other, so that the gap between them can be reduced. Pacing can be minimized. Further, unlike the recording by the magnetic head, the recording magnetic field does not spread due to the pole shape of the recording head. Therefore, the magnetic transition at the track end portion in the preformat recording is compared with the recording by the conventional magnetic head. It has excellent steepness and enables more accurate tracking.

[0015]

By the way, in recording an information signal using such a magnetic transfer technique, an array pattern corresponding to an information signal provided on a master information carrier is once used as a magnetization pattern on a magnetic recording medium. Since it is a method of transfer recording on the magnetic recording medium, it is important to uniformly and stably perform the magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium over the entire surface of the magnetic recording medium.

However, depending on various conditions at the time of preformat recording, the quality of the reproduced signal may be deteriorated or may be unstable depending on the position on the magnetic recording medium. Deterioration of the reproduction signal quality leads to a malfunction of servo tracking of the magnetic recording / reproducing apparatus.

In some cases, the deterioration phenomenon of signal quality can be prevented to some extent by experimentally optimizing various conditions during preformat recording.

However, when mass-producing magnetic recording / reproducing devices using the preformat recording technique, from the viewpoints of quality assurance of the product and improvement of production yield, a wide permissible range to some extent under appropriate preformat recording conditions. is necessary.

Under proper recording conditions derived by trial and error experimental techniques in the current preformat recording technology, the proper range allowable from the viewpoint of signal quality is very narrow, and product quality assurance during mass production, It is hard to say that it is sufficiently practical from the viewpoint of improving the production yield.

The present inventors have repeatedly conducted various experiments and studies to solve this problem, and as a result, have found that the above-mentioned signal quality deterioration phenomenon is due to the following action. The case where the magnetic recording medium is a disk-shaped magnetic recording medium will be described.

The length of each ferromagnetic thin film pattern on the master information carrier in the disk circumferential direction is the predetermined pulse interval on the time axis in the reproduced signal when the information recorded and transferred is reproduced by the magnetic head. Is designed to get you. However, since the rotational speed of the transferred disk-shaped magnetic recording medium is constant, the peripheral speed at one point on the disk is higher on the disk outer circumference than on the disk inner circumference. Therefore, in order to obtain a constant pulse interval from the inner circumference to the outer circumference in the signal waveform when a certain transferred and recorded signal is reproduced by the magnetic head, the length of the ferromagnetic thin film pattern in the disk circumferential direction is set to the outer circumference. It needs to be large.

That is, in order to obtain a constant pulse interval in a certain kind of signal, the lengths of the individual ferromagnetic thin films on the master information carrier and the intervals between the individual ferromagnetic thin films are set at the outer circumference rather than the inner circumference. Is getting bigger.

On the other hand, since the ferromagnetic thin film is deposited at a constant film forming rate by using a sputtering method or the like, its film thickness is generally constant regardless of the inner circumference and the outer circumference.
That is, the cross section of each ferromagnetic thin film has an elongated shape in which the ratio of length to film thickness (= length / film thickness) is smaller toward the inner circumference and the ratio of length to film thickness is larger toward the outer circumference.

In this way, in a ferromagnetic thin film pattern having a different cross-sectional shape, when a magnetic field for magnetic transfer is applied by a magnetizing head, the magnetization process and Transfer recording characteristics to the magnetic recording medium are different. That is, when the magnetic characteristics of the magnetic recording medium are uniform over the entire surface of the disk, the value of the applied magnetic field that obtains the optimum value in the leakage flux that contributes to the magnetization reversal and the optimum value in the transfer recording characteristics is the disk-shaped magnetic recording medium. Depends on the radial position of. Therefore, when transfer recording is performed in an applied magnetic field that can obtain good signal quality on the inner circumference side, the signal quality on the outer circumference side is below the allowable limit, or conversely, good signal quality is obtained on the outer circumference side. When transfer recording is performed in an applied magnetic field that can be applied, a phenomenon occurs in which the signal quality on the inner peripheral side deteriorates below the allowable limit.

The present invention has been made in view of the above circumstances, and is a master information carrier to be applied to a magnetic recording medium such as a disk-shaped magnetic recording medium, particularly a fixed hard disk medium, a removable hard disk medium, and a large capacity flexible medium. It is an object of the present invention to make it possible to perform magnetic transfer of the pattern corresponding to the above information signal uniformly and stably over the entire surface of the magnetic recording medium.

[0026]

The method of manufacturing a magnetic recording medium according to the present invention is premised on the following. A master information carrier on which a ferromagnetic thin film pattern corresponding to an information signal is formed is used. This master information carrier is superposed on a disk-shaped magnetic recording medium, and the magnetic head is magnetized to magnetize the magnetic portion of the pattern corresponding to the information signal on the master information carrier. As a result, the magnetic flux leaking from the magnetic portion of the pattern acts on the magnetic recording medium superposed on the master information carrier, and the pattern corresponding to the information signal on the master information carrier is magnetically transferred to the magnetic recording medium.

The present invention solves the above-mentioned problems by taking the following means in such a magnetic recording medium manufacturing method. That is, the magnetic flux for magnetic transfer is applied from the magnetizing head to the magnetic portion of the pattern corresponding to the information signal on the master information carrier by the leakage magnetic flux of the magnetizing head. The magnetic field is applied in a state where the applied magnetic field is reduced toward the outer peripheral side of the recording medium.

The operation of the present invention is as follows. The present inventors have clarified the magnetic mechanism that makes the optimum magnetic field value different in the radial position of the disk as follows.

In other words, the outer peripheral pattern having a large length / thickness ratio (= length / thickness) has a small demagnetizing field in the direction in which the magnetic field is applied by the magnetizing head, and is saturated at a smaller magnetic field value. Easy to reach. On the contrary, in the pattern on the inner circumference where the ratio of the length to the film thickness is small, the demagnetizing field in the direction of the applied magnetic field by the magnetizing head is larger than that on the outer circumference. Therefore, in order to obtain the same value in the leakage magnetic flux that contributes to the magnetization reversal of the region corresponding to the space between the ferromagnetic thin films on the disk-shaped magnetic recording medium, the applied magnetic field needs to be larger at the inner circumference than at the outer circumference. become. In this way, when transfer recording is performed using the applied magnetic field that can obtain the optimum leakage magnetic flux at the outer periphery and the optimum signal quality,
Sufficient magnetization reversal cannot be obtained in the region between the ferromagnetic thin films on the inner circumference side, and the signal quality deteriorates. On the contrary, when transfer recording is performed using an applied magnetic field capable of obtaining the optimum leakage magnetic flux in the inner circumference and obtaining the optimum signal quality, the ferromagnetic thin film on the outer circumference side reaches saturation. In other words, the application of the applied magnetic field causes leakage flux even on the ferromagnetic thin film, causing unnecessary magnetization reversal of the magnetic recording medium, resulting in deterioration of signal quality.

As described above, the optimum value of the magnetic field to be applied to the magnetic recording medium by the magnetic flux leaking from the magnetizing head is
Based on the finding that the inner peripheral side is larger than the outer peripheral side, in the present invention, the magnetic field applied to the master information carrier by the magnetic flux leaking from the magnetizing head is applied to the outer peripheral side of the magnetic recording medium. The magnetic field is configured to be smaller than the applied magnetic field on the inner circumference side. As a result, a sufficient magnetization reversal is obtained on the inner peripheral side, and the generation of reverse polarity leakage magnetic flux on the ferromagnetic thin film is suppressed below the permissible range on the outer peripheral side, so that good magnetic reversal is achieved regardless of the radial position of the magnetic recording medium. The signal quality can be obtained.

According to the present invention having this structure, the magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium can be uniformly and stably performed over the entire surface of the magnetic recording medium.

With respect to the magnetizing head used in the above-mentioned magnetic recording medium manufacturing method, the present invention has a surface of the magnetizing head facing the master information carrier, that is, a head main surface, as follows. That is, with respect to the distance between the main surface of the head and the master information carrier, the outer peripheral side of the magnetic recording medium is set to a larger distance, the inner peripheral side of the magnetic recording medium is set to a smaller distance, and the distance is monotonously and continuously. It is formed in a changing tapered shape or curved shape.

According to the invention of the magnetizing head,
In carrying out the above-mentioned magnetic recording medium manufacturing method capable of performing magnetic transfer of a pattern corresponding to an information signal on the master information carrier to the magnetic recording medium uniformly and stably over the entire surface of the magnetic recording medium, a comparison is made. It can be realized easily and inexpensively.

Further, according to the present invention, it is possible to realize a hard disk drive having a built-in magnetic recording medium preformatted by using the above magnetic recording medium manufacturing method.

Further, according to the present invention, a magnetic recording / reproducing apparatus incorporating a magnetic recording medium in which a magnetic pattern of a predetermined information signal is magnetically transferred to a magnetic film in advance by using the above-described magnetic recording medium manufacturing method is realized. be able to.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

In the magnetic recording medium manufacturing method of the present invention , the master information carrier is superposed on the disk-shaped magnetic recording medium, and the master information is applied by a magnetic field applied by a magnetizing head.
Through the magnetizing magnetic part of the support, a magnetic recording medium manufacturing method of magnetically transferring information signals corresponding pattern on the master information carrier with the magnetic flux leakage from the magnetic portion to the magnetic recording medium, wherein Master information carrier and before
The distance between the recording magnetizing head and the head is larger on the outer peripheral side.
The magnetizing head by facing each other
Applied magnetic field is smaller toward the outer circumference of the magnetic recording medium.
It is characterized in that the magnetic transfer is performed in the state of being.

The operation of the magnetic recording medium manufacturing method of the present invention is substantially the same as that described in the above section [Means for Solving the Problems]. That is,
The magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium can be uniformly and stably performed over the entire surface of the magnetic recording medium. The magnet of the present invention
The method of manufacturing a magnetic recording medium is the method of manufacturing the master information carrier and the recording medium.
The distance between the magnetic head and the magnetic head is much larger on the outer peripheral side.
Since the magnetic transfer is performed by facing each other in the state of
Simply adjust the spacing of the magnetizing head from the carrier
Master information for magnetic recording media can be obtained by a simple method.
Magnetic recording of magnetic transfer of pattern corresponding to information signal on carrier
Can be performed uniformly and stably over the entire surface of the medium
It That is, it is possible to respond relatively easily and inexpensively.
Wear.

[0039]

[0040]

The magnetic recording medium manufacturing method of the present invention is
In one embodiment, as the magnetizing head, a magnetizing head obtained by joining a first magnetic core half body and a second magnetic core half body in a gap forming state is used. According to this embodiment , since the magnetizing head of the type with a gap is used, the magnetic flux emitted from the gap to the outside is larger than that of the magnetizing head of the type without a gap. It becomes easier to act on the corresponding pattern.

The magnetic recording medium manufacturing method of the present invention is
In one embodiment, the magnetizing head includes the first
At least one of the magnetic core half body and the second magnetic core half body is composed of a permanent magnet. This is to form an annular magnetic path for magnetization.

The magnetic recording medium manufacturing method of the present invention is
In one embodiment, the magnetizing head includes the first
The magnetizing head is used in which the magnetic core half body and the second magnetic core half body are joined together with a permanent magnet interposed therebetween .

In this embodiment , a permanent magnet is interposed between the first magnetic core half body and the second magnetic core half body on the opposite side of the gap, so that the first magnetic core half body and the second magnetic core half body are separated from each other. The magnetic core halves can be uniformly magnetized in the direction along the annular magnetic path of the magnetic circuit formed by them. As the interposing permanent magnet, it is possible to use a block-shaped rectangular parallelepiped. Compared with a magnetizing head that uses a yoke-type permanent magnet, a magnetizing head that uses a rectangular parallelepiped permanent magnet is cheaper,
Magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium can be carried out at a lower cost.

The magnetic recording medium manufacturing method of the present invention is
In one embodiment, the magnetizing head includes the first
A magnetic head in which at least one of the magnetic core half body and the second magnetic core half body includes a DC excitation winding.
To use.

In this embodiment, it is necessary to uniformly magnetize the yoke-shaped first and second magnetic core halves in a direction along the annular magnetic path of the magnetic circuit formed by them. Depending on the shape of the core, it may be difficult to magnetize uniformly along the annular magnetic path. When the core is excited by the DC excitation winding, the first magnetic core half body and the second magnetic core half body are uniformly magnetized in the direction along the annular magnetic path of the magnetic circuit formed by the first magnetic core half body and the second magnetic core half body. Will be sure to do.

The magnetic recording medium manufacturing method of the present invention is
In one embodiment, as the magnetizing head, a magnetizing head composed of a substantially hexahedral permanent magnet block is used.
It This magnetizing head is a gapless type.

In this embodiment, since it has a substantially hexahedral shape (rectangular parallelepiped shape), it is necessary to have a stronger residual magnetic flux density than the gap type, but since the shape is simple, it is inexpensive and the uniform magnetic flux is uniform. Is easy to magnetize and is easy to handle.

The magnetic recording medium manufacturing method of the present invention is
In one embodiment , prior to the step of magnetic transfer, a step of applying a DC erasing magnetic field to the magnetic recording medium to magnetize the magnetic recording medium in a certain direction, and the master information carrier is attached to the magnetized magnetic recording medium. In the step of magnetic transfer in the superposed state, by applying a magnetic field having a polarity opposite to the DC erasing magnetic field to the magnetic part of the master information carrier by using the magnetizing head, A pattern corresponding to the information signal is magnetically transferred to the magnetic recording medium.

In this embodiment, the magnetic recording medium is subjected to direct current erasure in advance to be uniformly magnetized, and a magnetic field having a reverse polarity is applied to the magnetic recording medium in the uniformly magnetized state to thereby obtain the master information. Since the pattern corresponding to the information signal on the carrier is magnetically transferred, the steepness of the magnetization transition at the boundary between the information signal region and the non-information signal region is high.

The magnetic recording medium manufacturing method of the present invention is
One In embodiments, the DC erasing magnetic field applied to the magnetic recording medium, applies a substantially constant DC erasing magnetic field in the radial direction of the magnetic recording medium.

In this embodiment , the magnetic field applied from the magnetizing head to the master information carrier when magnetically transferring the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium is applied to the outer peripheral side as described above. It is preferable to make the magnetic field smaller than the applied magnetic field on the inner circumference side. However, regarding the initial magnetization (DC erase) of the magnetic recording medium prior to magnetic transfer, it is preferable to make the DC erase magnetic field different in the radial direction. is not. For the initial magnetization, a constant DC erasing field in the radial direction has favorable results in the subsequent magnetic transfer of the pattern corresponding to the information signal on the master information carrier.

The above embodiment relates to a magnetizing head used in the above-described magnetic recording medium manufacturing method.

In the magnetizing head for manufacturing a magnetic recording medium of the present invention , the master information carrier is a disk-shaped magnetic recording medium.
The magnetic part of the master information carrier is
The magnetic flux leaked from the magnetic part
The pattern corresponding to the information signal on the master information carrier is
A method of manufacturing a magnetic recording medium for magnetically transferring to a magnetic recording medium
For magnetizing the magnetic part of the master information carrier
A magnetizing head for applying an applied magnetic field, comprising:
The head is composed of the first magnetic core half and the second magnetic core half.
The first magnetic core half and the second magnetic core half
On the main surface of the head where the body faces the master information carrier
The magnetic recording, which is bonded in a gap forming state,
To reduce the applied magnetic field toward the outer peripheral side of the medium,
The main surface of the head should be spaced apart from the master information carrier.
It becomes monotonically and continuously larger toward the outer peripheral side of the magnetic recording medium.
The taper shape or curved surface
It is a sign .

A magnetizing head for manufacturing the magnetic recording medium of the present invention.
The action of the do is as follows. In order to perform the magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium uniformly and stably over the entire surface of the magnetic recording medium, for the magnetic field applied from the magnetizing head to the master information carrier, It is better to make the outer peripheral side applied magnetic field smaller than the inner peripheral side applied magnetic field, but one of the simplest measures in the magnetizing head for compensating for this is the tenth invention. There is. That is, the head main surface of the magnetizing head that faces the master information carrier is not uniform in the dimension of separation from the master information carrier as in the conventional case, but is provided with a difference in the radial direction. Based on the distance on the inner circumference side, the distance is gradually increased toward the outer circumference. It is described as monotonous and continuous. The shape may be a tapered shape or a curved shape. Note that the shape may be the same as that of the conventional one, and the posture may be tilted.

For magnetization for producing the above-mentioned magnetic recording medium of the present invention
In the head , the magnetizing head further comprises a first magnetic core half body and a second magnetic core half body, and the first magnetic core half body and the second magnetic core half body are in a gap formation state. It is said to be joined to. This describes that the magnetizing head in the present invention is of the type with a gap. In the gap type magnetizing head, the magnetic flux emitted from the gap to the outside easily acts on the pattern corresponding to the information signal on the master information carrier, as compared with the non-gap type magnetizing head. Therefore, the degree of magnetization in the magnetic core may be low.

For magnetization for producing the above-mentioned magnetic recording medium of the present invention
In one embodiment of the head, at least one of the first magnetic core half body and the second magnetic core half body is composed of a permanent magnet.

In this embodiment, it is preferable that the first magnetic core half body and the second magnetic core half body are uniformly magnetized in the direction along the annular magnetic path of the magnetic circuit constituted by them. However, the homogenization of the magnetization direction is realized by configuring at least one of the magnetic core halves with a permanent magnet. In addition, as a permanent magnet, Nd-Fe-B or Sm is used.
A rare earth magnet containing a material such as —Co as a main component is preferable.

For magnetization for producing the magnetic recording medium of the present invention.
Head, in one embodiment, the a first magnetic core half body and the second magnetic core halves are joined in a state of interposing the permanent magnet therebetween.

In this embodiment , the permanent magnet to be interposed between the first magnetic core half body and the second magnetic core half body on the opposite side of the gap is usually a block type rectangular parallelepiped. It becomes possible. A magnetizing head using a rectangular parallelepiped permanent magnet can be realized at a lower cost than a magnetizing head using a yoke-type permanent magnet. Further, as a material forming the first and second magnetic core halves, various types of ferromagnetic materials having soft magnetism or semi-hard magnetism can be used instead of permanent magnet materials.

The ferromagnetic materials forming the first and second magnetic core halves have sufficiently high saturation magnetic flux densities so that the magnetic flux supplied from the permanent magnet does not cause significant magnetic saturation locally. Preferably, for example, F
e, Fe-Co alloys, Fe-Si based soft magnetic alloy materials and the like are preferable.

For magnetization for producing the above-mentioned magnetic recording medium of the present invention
Head, in one embodiment, at least one of said first magnetic core half body and the second magnetic core half is provided with a DC excitation winding.

In this embodiment, it is necessary to uniformly magnetize the first and second magnetic core halves having the yoke shape in the direction along the annular magnetic path of the magnetic circuit formed by them. Depending on the shape of the core, it may be difficult to magnetize uniformly along the annular magnetic path. On the other hand, if the core is excited by the DC excitation winding, the magnetization directions can be made uniform, and the first and second windings can be made uniform.
The material forming the magnetic core half body does not have to be a permanent magnet material, and various types of ferromagnetic materials having soft magnetism or semi-hard magnetism can be used. That is, it is not necessary to provide a permanent magnet as a constituent element of the magnetic core, the troublesomeness of magnetizing in a proper direction can be eliminated, and the yoke-shaped magnetic core half body can be easily formed.

The magnetizing head of the present invention carries the master information.
With the body overlaid on the disk-shaped magnetic recording medium
By magnetizing the magnetic part of the master information carrier,
The master information carrier with the leakage magnetic flux from the magnetic part
A pattern corresponding to the above information signal is magnetically recorded on the magnetic recording medium.
In the method of manufacturing a magnetic recording medium for transfer, the master information is
Magnetization that gives an applied magnetic field to magnetize the magnetic part of the carrier
And a magnetizing head, wherein the magnetizing head has a substantially hexahedral shape.
The permanent magnet block of
To reduce the applied magnetic field toward the outer peripheral side of the recording medium,
Heads facing the hexahedral master information carrier
When the main surface is separated from the master information carrier,
A test that increases monotonically and continuously toward the outer circumference of the magnetic recording medium.
Characterized by being formed into a curved or curved shape
is doing. This magnetizing head is a gapless type.

The operation of the magnetizing head of the present invention is as follows. Since it is a roughly hexahedral shape (rectangular parallelepiped shape), it is necessary to have a stronger residual magnetic flux density than the gap type, but since the shape is simple, it is inexpensive and it is easy to magnetize uniform magnetic flux. It is also easy to handle.

[0066]

[0067]

[0068]

[0069]

(Specific Embodiments) Hereinafter, specific embodiments of the magnetic recording medium manufacturing method according to the present invention will be described with reference to the drawings.

(Embodiment 1) A method of manufacturing a magnetic recording medium (a method of recording on a magnetic recording medium) according to Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 shows an outline of a recording apparatus for carrying out the recording method according to the present embodiment. In FIG. 1, a disk-shaped hard disk 1 as a magnetic recording medium has a donut disk-shaped non-magnetic substrate surface having a central hole 1a.
It is configured by forming a ferromagnetic thin film containing Co or the like as a main component by a sputtering method.

Reference numeral 2 denotes a disc-shaped master information carrier which is arranged so as to be in contact with the surface of a magnetic film made of a ferromagnetic thin film of the hard disk 1. The master information carrier 2 is generally the hard disk. A signal area 2a having a diameter larger than that of the hard disk 1 and formed of a ferromagnetic thin film having a fine array pattern corresponding to an information signal to be magnetically transferred to the hard disk 1 is provided on the surface of the side in contact with the hard disk 1. .

Reference numeral 3 denotes a disk holder for holding the hard disk 1, and a chuck portion 3a for positioning and holding the hard disk 1 is provided at the tip of the disk holder 3. Further, inside the disk holder 3, there is provided a suction hole 3b communicating with the central hole 1a of the hard disk 1 and having one end connected to the exhaust duct 4.

Further, the exhaust device 5 is provided at the end of the exhaust duct 4.
When the exhaust device 5 is started, the space between the hard disk 1 and the master information carrier 2 becomes a negative pressure state through the exhaust duct 4 and the suction hole 3b of the disk holder 3, and as a result, , The master information carrier 2 is sucked in the direction of the hard disk 1, and the hard disk 1 is superposed on the master information carrier 2 while being positioned. At this time, a slight gap groove may be formed on the surface of the master information carrier 2 in a region other than the signal region 2a, and air between the hard disk 1 and the master information carrier 2 may be sucked through the gap groove. .

The magnetizing head 6 is for transferring and recording from the master information carrier 2 to the hard disk 1, and corresponds to the information signal formed on the master information carrier 2 by the magnetic field applied from the magnetizing head 6. The ferromagnetic thin film pattern is magnetized, and an information signal is recorded on the hard disk 1 by the magnetic flux leaked therefrom (magnetic transfer).

This magnetizing head 6 has, for example, as shown in FIG. 2, a first magnetic core half 6b made of a ferromagnetic material.
And a second magnetic core half 6c made of a ferromagnetic material having a winding 6a are opposed to each other to form an annular magnetic circuit having a gap 6d. An exciting current is applied to the winding 6a. By doing so, the gap 6d has an arrow A
As shown by, a leakage magnetic flux is generated from the first magnetic core half body 6b toward the second magnetic core half body 6c, and the direction of the applied magnetic flux is changed to change the direction of the leakage magnetic flux generated in the gap 6d. be able to.

The arrow B indicates the direction of the internal magnetic flux generated in the magnetic core halves 6b and 6c when the leakage magnetic flux in the direction shown in FIG. 2 is generated.

Further, as shown in FIG. 3, the magnetizing head 6
The shape of the gap 6d is the same arc shape as the tracking scanning trajectory (rotational trajectory of the head actuator tip) of the recording / reproducing magnetic head on the head main surface that is the surface facing the master information carrier 2. Therefore, the direction of the magnetic field generated in the gap 6d is always perpendicular to the tracking scanning orbit, and the ferromagnetic thin film of the master information carrier 2 is perpendicular to the tracking scanning direction of the recording / reproducing magnetic head in all tracks. Is magnetized. That is, the recording / reproducing magnetic head is magnetized in the same direction as the head gap length direction.

Next, an example of the master information carrier used in the magnetic recording medium manufacturing method of the present invention will be described.

FIG. 4 schematically shows a plane of an example of the master information carrier 2. As shown in FIG. 4, one side of the master information carrier 2 that is in contact with the surface of the ferromagnetic thin film of the hard disk 1. On the surface of the
a is formed.

An enlarged view of the portion C surrounded by the dotted line in FIG. 4 is schematically shown in FIG. As shown in FIG. 5, in the signal area 2a, at a position corresponding to a digital information signal recorded on the hard disk 1, for example, preformat recording, a magnetic portion formed of a ferromagnetic thin film in a pattern shape corresponding to the information signal is formed. A master information pattern is formed. In FIG. 5, the hatched portion is a magnetic portion formed of a ferromagnetic thin film. The master information pattern shown in FIG. 5 is obtained by sequentially arranging areas of the clock signal, the tracking servo signal, the address information signal, etc. in the track length direction. The master information pattern shown in FIG. 5 is an example, and the configuration, arrangement, etc. of the master information pattern will be appropriately determined according to the digital information signal recorded on the hard disk 1.

For example, in a hard disk drive, when a reference signal is first recorded on a magnetic film of the hard disk and preformat recording such as a tracking servo signal is performed based on the reference signal, the master information carrier is used for the hard disk. Only the reference signal used for pre-format recording is transferred and recorded on the magnetic film in advance, and the hard disk is installed in the drive housing. Pre-format recording such as tracking servo signals is performed using the magnetic head of the hard disk drive. It may be performed. In this case, the final preformat recording is performed by the magnetic head mounted in the drive as in the conventional method. However, since the drive itself can refer to the reference signal transferred and recorded to complete the final preformat recording without using an expensive dedicated servo recording device, the final preformat information signal is As in the case of direct transfer recording,
The cost merit is greater than that of the conventional method.

A partial cross section of the region shown in FIGS. 4 and 5 is shown in FIG.
Shown in. As shown in FIG. 6, the master information carrier 2 is S
A plurality of fine array patterns corresponding to information signals are formed on one main surface 10b of the disk-shaped substrate 10 made of a non-magnetic material such as an i substrate, a glass substrate, a plastic substrate, that is, the surface on the side where the surface of the hard disk 1 contacts. Recess 10 in shape
a is formed, and the ferromagnetic thin film 11 which is a magnetic part is embedded in the recess 10a of the base 10 so as to be formed. Here, in order to bring the hard disk 1 and the master information carrier 2 into close contact with each other uniformly using the recording apparatus shown in FIG. 1 to obtain good recording characteristics, the surface 11a of the ferromagnetic thin film 11 is as flat as possible and the substrate is One main surface 10
It is preferable to have a configuration projecting with respect to 0b.

As the ferromagnetic thin film 11, a hard magnetic material,
Many kinds of magnetic materials can be used regardless of whether they are semi-hard magnetic materials or soft magnetic materials, as long as they can transfer and record digital information signals on a magnetic recording medium (hard disk). For example, Fe, Co, an Fe-Co alloy, or the like can be used. In order for the master information carrier to generate a sufficient recording magnetic field regardless of the type of magnetic recording medium on which the information signal is recorded, it is preferable that the saturation flux density of the magnetic material is large. In particular, 2000 Oersted (1
For a magnetic disk with a high coercive force exceeding 59 kA / m) or a flexible disk with a large magnetic layer thickness, sufficient recording may not be possible when the saturation magnetic flux density is 0.8 Tesla or less. 0.8
A magnetic material having a saturation magnetic flux density of Tesla or more, preferably 1.0 Tesla or more is used.

The thickness of the ferromagnetic thin film 11 depends on the bit length, the saturation magnetization of the magnetic recording medium and the film thickness of the magnetic layer. For example, the bit length is about 1 μm, and the saturation magnetization of the magnetic recording medium is about 50.
0 emu / cc (500 kA / m), 50 nm to 500 when the thickness of the magnetic layer of the magnetic recording medium is about 20 nm.
It may be about nm.

Here, in such a recording method, in order to obtain a good recording signal quality, based on the arrangement pattern shape of the soft magnetic thin film or the semi-hard magnetic thin film as the ferromagnetic thin film provided on the master information carrier, During preformat recording, it is desirable to excite this to uniformly magnetize it, and it is desirable to uniformly perform DC erasure on a magnetic recording medium such as a hard disk before signal recording using the master information carrier.

Next, a procedure for recording an information signal corresponding to the pattern shape formed on the master information carrier on a hard disk which is a disk-shaped magnetic recording medium will be described.

First, as shown in FIG. 7, the magnetizing head 6 is used.
When the disk is brought close to the hard disk 1, the disk is rotated in parallel with the hard disk 1 with the central axis of the hard disk 1 as a rotation axis, so that the hard disk 1 is magnetized in one direction in advance as shown by an arrow in FIG. 8 (initial magnetization).

Next, as shown in FIG. 1, with the master information carrier 2 positioned and superposed on the hard disk 1, the exhaust device 5 is started to start the master information carrier 2 through the center hole 1a of the hard disk 1. Are sucked, and the surface of the master information carrier 2 on which the ferromagnetic thin film 11 is formed and the hard disk 1 are superposed so as to be uniformly adhered over the entire surface.

After that, as shown in FIG. 9, the magnetic field applied by the magnetizing head 6 has a polarity opposite to that of the initial magnetization, and the center of the hard disk 1 held by the disk holder 3 is rotated. By rotating the magnetizing head 6 in parallel with the master information carrier 2 as a center, a DC exciting magnetic field is applied to the master information carrier 2. As a result, the ferromagnetic thin film 11 of the master information carrier 2 is magnetized,
Then, as shown in FIG. 10, an information signal corresponding to the pattern shape of the magnetic portion formed by the ferromagnetic thin film 11 is recorded in a predetermined area 1b of the hard disk 1 which is superposed on the master information carrier 2. The arrow shown in FIG. 10 indicates the direction of the magnetization remaining outside the area 1b of the hard disk 1 where the information signal is recorded.

FIG. 11 shows details of the magnetization during recording of the information signal. As shown in FIG. 11, in the state where the master information carrier 2 is closely attached to the hard disk 1 which is a magnetic recording medium, a magnetic field is applied to the master information carrier 2 from the outside to magnetize the ferromagnetic thin film 11 to thereby hard disk 1 An information signal can be recorded on the magnetic recording layer 1c made of a ferromagnetic thin film. That is, by using the master information carrier 2 formed by forming the ferromagnetic thin film 11 in a predetermined pattern shape on the non-magnetic substrate 10, the hard disk 1 which is a magnetic recording medium for digital information signals.
Can be magnetically transferred and recorded.

Here, the transfer recording method will be described in more detail. The above-mentioned pre-format recording process is shown in FIG. 12, where FIG. 12 (a) is a DC erasing process of the hard disk 1 which is a magnetic recording medium, and FIG. 12 (b) is an information signal recording process using the master information carrier 2. , And FIG. 7C show the remanent magnetization state of the hard disk 1 after preformat recording, in cross sections in the information signal track length direction. When this magnetic recording medium is a hard disk, the information signal track length direction coincides with the disk circumferential direction.

As shown in FIG. 12A, the magnetic recording layer 1c on the hard disk 1 has a magnetization 13 in a fixed direction by a DC erasing magnetic field 12 prior to transfer recording of an information signal using the master information carrier 2. So that the direct current is uniformly erased. Next, as shown in FIG. 12B, the surface of the master information carrier 2 on which the ferromagnetic thin film 11 is formed in the array pattern shape corresponding to the information signal is formed on the magnetic recording layer 1c on the hard disk 1 which is a magnetic recording medium. Then, the ferromagnetic thin film 11 is excited by the direct-current exciting magnetic field 14 from the magnetizing head 6. At this time, the polarity of the DC excitation magnetic field 14 is
The polarity is opposite to that of the DC erasing magnetic field 12. As a result, the magnetization 13 on the hard disk 1 is reversed by the leakage magnetic flux 15 only in the portion between the ferromagnetic thin films 11. As a result, after removing the master information carrier 2, a pattern of the magnetization 13 corresponding to the array pattern shape of the ferromagnetic thin films 11 formed on the master information carrier 2 can be recorded on the hard disk 1.

As described above, in the method of transfer recording from the master information carrier to the magnetic recording medium of the present invention, the master information carrier has an array pattern shape corresponding to a predetermined digital information signal to be recorded on the magnetic recording medium. A magnetic portion made of a ferromagnetic thin film is formed in advance, the magnetic recording medium is brought into contact with the master information carrier, and the array pattern shape formed on the master information carrier is transferred and recorded on the magnetic recording medium as a magnetization pattern. In such a method, it is important to reliably and accurately transfer the array pattern of the magnetic parts formed on the master information carrier as the corresponding magnetization pattern.

However, when the present inventors performed preformat recording on a magnetic recording medium such as a hard disk using the above-mentioned configuration, the quality of the reproduced signal deteriorates depending on various conditions during preformat recording. Alternatively, a phenomenon of unknown origin, which is unstable depending on the position on the magnetic recording medium, was observed. When such reproduction signal quality is deteriorated, it may be difficult to perform servo tracking of the magnetic recording / reproducing apparatus using the preformat recording signal.

In some cases, such a deterioration phenomenon of signal quality can be prevented to some extent by experimentally optimizing various conditions during preformat recording. However, when mass-producing magnetic recording / reproducing devices using the above-described pre-format recording technology, from the viewpoints of product quality assurance and production yield improvement, a wide range of acceptable pre-format recording conditions is acceptable. Range is required. Under the proper recording conditions derived by trial and error experimental methods in the current pre-format recording technology, the appropriate range allowed from the viewpoint of signal quality is very narrow, product quality assurance in mass production, and production yield. It is hard to say that it is sufficiently practical from the viewpoint of improvement.

The present inventors have repeatedly conducted various experiments and studies to solve this problem, and as a result, have found that the above-mentioned phenomenon of signal quality deterioration is due to the following action.

The lengths of the individual ferromagnetic thin film patterns on the master information carrier 2 in the disk circumferential direction as shown in FIGS. 4 and 5 are the same as those obtained when the transferred and recorded information is reproduced using the magnetic head. The signal is designed to obtain a predetermined pulse interval on the time axis. However, since the rotation speed of the hard disk transferred and recorded in the hard disk drive is constant, the peripheral speed at one point on the disk is higher on the disk outer circumference than on the disk inner circumference. Therefore, in order to obtain a constant pulse interval from the inner circumference to the outer circumference in the signal waveform when a certain transferred and recorded signal is reproduced by the magnetic head, the length of the ferromagnetic thin film pattern in the disk circumferential direction is set to the outer circumference. It needs to be large. That is, to explain with reference to the sectional view of FIG. 6, in order to obtain a constant pulse interval in a certain kind of signal, the length of each ferromagnetic thin film 11 on the master information carrier 2 and each ferromagnetic thin film 11 are obtained. The distance between the outer peripheral side is larger than the inner peripheral side.

On the other hand, since the ferromagnetic thin film 11 is deposited at a constant film forming rate by using the sputtering method or the like, its thickness is generally constant regardless of the inner circumference side and the outer circumference side. . That is, the cross section of each ferromagnetic thin film 11 has an elongated shape in which the ratio of the length and the film thickness (= length / film thickness) is smaller toward the inner circumference and is larger toward the outer circumference.

As described above, in the ferromagnetic thin film patterns having different cross-sectional shapes, when a DC exciting magnetic field 14 is applied as shown in FIG. The process and transfer recording characteristics to the disk-shaped magnetic recording medium are different. That is, when the magnetic characteristics of the disk-shaped magnetic recording medium are uniform over the entire surface of the disk, the value of the DC magnetic field 14 that obtains the optimum value in the leakage flux 15 that contributes to the magnetization reversal and the optimum value in the transfer recording characteristics is It depends on the radial position of the disk-shaped magnetic recording medium. Therefore, when transfer recording is performed in the DC excitation magnetic field 14 capable of obtaining good signal quality on the inner circumference side, the signal quality on the outer circumference side is below the allowable limit, or conversely, good signal quality on the outer circumference side. When the transfer recording is performed in the DC exciting magnetic field 14 that can obtain the above, there occurs a phenomenon that the signal quality on the inner peripheral side deteriorates to the allowable limit or less.

As a result of examining the above phenomenon in more detail, the present inventors have clarified the magnetic mechanism for making the optimum DC exciting magnetic field value different depending on the radial position of the disk as follows.

That is, the outer peripheral pattern having a large length / thickness ratio (= length / thickness) has a small demagnetizing field in the direction in which the DC exciting magnetic field 14 is applied, and thus tends to reach saturation at a smaller magnetic field value. On the contrary, in the pattern on the inner circumference where the ratio of the length to the film thickness is small, the demagnetizing field in the direction in which the DC exciting magnetic field 14 is applied is larger than that on the outer circumference. Therefore, in order to obtain the same value in the leakage magnetic flux 15 that contributes to the magnetization reversal of the region corresponding to between the ferromagnetic thin films on the hard disk 1, a DC exciting magnetic field larger than the outer circumference is required in the inner circumference. . As described above, when the optimum leakage magnetic flux 15 is obtained on the outer circumference and the transfer recording is performed using the DC exciting magnetic field capable of obtaining the optimum signal quality, the area corresponding to the ferromagnetic thin film on the inner circumference side is sufficient. The magnetization reversal cannot be obtained, and the signal quality is deteriorated. On the contrary, when the optimum leakage magnetic flux 15 is obtained in the inner circumference and the transfer recording is performed by using the direct-current exciting magnetic field capable of obtaining the optimum signal quality, the ferromagnetic thin film 11 on the outer circumference side reaches saturation. That is, the application of the direct-current exciting magnetic field 14 generates a magnetic flux on the ferromagnetic thin film 11 having a polarity opposite to that of the initial magnetization of the hard disk 1, and demagnetizes or erases the initial magnetization, which deteriorates the signal quality.

As described above, it has been found that the optimum value of the DC exciting magnetic field to be applied to the hard disk 1 by the magnetic flux leaking from the magnetizing head 6 is larger on the inner side of the disk than on the outer side thereof. Based on the present invention, the magnetic field applied to the master information carrier 2 by the magnetic flux leaking from the magnetizing head 6 is such that the applied magnetic field on the outer peripheral side of the hard disk 1 is smaller than the applied magnetic field on the inner peripheral side. To do. As a result, sufficient magnetization reversal is obtained on the inner circumference side, and on the outer circumference side, the generation of leakage magnetic flux of opposite polarity on the ferromagnetic thin film is suppressed below the allowable range,
Good signal quality can be obtained regardless of the disk radial position.

Regarding the magnetic field applied to the master information carrier 2 by the magnetic flux leaking from the magnetizing head 6, the present inventors have a structure in which the applied magnetic field on the outer peripheral side of the hard disk 1 is smaller than the applied magnetic field on the inner peripheral side. A magnetic head 6 and a magnetic recording method using the same have been found, which can realize the above relatively easily and inexpensively.

That is, in the magnetic recording medium manufacturing method of the present invention, by using the magnetizing head 6 having a specific configuration and shape, the magnetic flux leaking from the magnetizing head 6 is applied to the master information carrier 2. For magnetic fields,
The applied magnetic field on the outer peripheral side of the hard disk 1 can be configured to be smaller than the applied magnetic field on the inner peripheral side.

Below, with respect to the magnetic field applied to the magnetizing head 6 used in the magnetic recording medium manufacturing method of the present invention, that is, the master information carrier 2, the applied magnetic field on the outer peripheral side is higher than the applied magnetic field on the inner peripheral side. Magnetizing head 6 for reduction
The configuration of will be described.

(Second Embodiment) FIG. 13 shows an example of a magnetizing head of the present invention. FIG. 13 shows a master information carrier in which a magnetizing head 6 is constructed by forming a ring-shaped magnetic circuit having a gap 6d by opposing a first magnetic core half body 6b and a second magnetic core half body 6c. It is a perspective view which shows the mode that it was arrange | positioned facing 2. In the magnetizing head 6 shown in FIG. 13, the distance D _O between the master information carrier 2 and the magnetizing head 6 at the position corresponding to the outer peripheral side of the hard disk 1 is at the position corresponding to the inner peripheral side of the hard disk 1. The master information carrier 2 is larger than the separation dimension D _I between the magnetizing head 6 and the master information carrier 2
The distance between the hard disk 1 and the hard disk 1 is configured to change monotonously and continuously in the radial direction of the hard disk 1. In order to realize such a configuration, in the example shown in FIG. 13, the head main surface, which is one main surface of the magnetizing head 6 facing the master information carrier 2, is processed into a tapered shape. It may be processed into a curved shape depending on the embodiment. With such a configuration, even when the first magnetic core half body 6b and the second magnetic core half body 6c are uniformly excited, the magnetic flux leaking from the magnetizing head 6 is applied to the master information carrier 2. It is possible to configure the generated magnetic field to be smaller at the position corresponding to the outer peripheral side of the hard disk 1 than at the position corresponding to the inner peripheral side.

The cross section parallel to the annular magnetic path of the magnetic circuit in the magnetizing head 6 shown in FIG. 13, that is, the track length direction of the information signal, for example, the cross section in the circumferential direction of the hard disk 1 which is a disk-shaped magnetic recording medium. An example is shown in FIG.
Shown in.

FIG. 14 shows an example in which, in addition to the configuration of FIG. 13, both or one of the first magnetic core half body 6b and the second magnetic core half body 6c is made of a permanent magnet material.
First magnetic core half 6b and second magnetic core half 6c
Both or one of them is uniformly magnetized in the direction along the annular magnetic path of the magnetic circuit formed by them. This first
As a permanent magnet material constituting at least one of the magnetic core half body 6b and the second magnetic core half body 6c, one having a residual magnetic flux density of 1.0 tesla or more and a coercive force of 10,000 oersted (796 kA / m) or more is preferable. . As a permanent magnet having such characteristics, Nd-Fe-B and Sm-
A rare earth magnet containing a material such as Co as a main component can be used.

A cross section parallel to the annular magnetic path of the magnetic circuit in the magnetizing head 6 shown in FIG. 13, that is, a cross section in the track length direction of the information signal, for example, in the circumferential direction of the hard disk 1 which is a disk-shaped magnetic recording medium. Another example is shown in FIG.

In the example shown in FIG. 15, in addition to the configuration of FIG. 13, at least one of the first magnetic core half body 6b and the second magnetic core half body 6c has a winding 6a for direct-current exciting them. Is arranged. In the example of FIG. 15, the winding 6a is provided on the side of the second magnetic core half body 6c.

In the embodiment shown in FIG. 14, the first magnetic core half body 6b and the second magnetic core half body 6c each having a yoke shape are uniformly oriented in the direction along the annular magnetic path of the magnetic circuit constituted by them. However, depending on the shape of the core, it may be difficult to uniformly magnetize in the direction along the annular magnetic path. On the other hand, in the configuration of the example shown in FIG. 15, since the core is excited by the winding current, the material forming the first and second magnetic core halves 6b and 6c may not be the permanent magnet material. It is possible to use various types of ferromagnetic materials having soft magnetism or semi-hard magnetism. That is, it is not necessary to provide a permanent magnet as a constituent element of the magnetic core, and it is possible to eliminate the trouble of magnetizing in a proper direction.

A cross section parallel to the annular magnetic path of the magnetic circuit in the magnetizing head 6 shown in FIG. 13, that is, the track length direction of the information signal, for example, the cross section in the circumferential direction of the hard disk 1 which is a disk-shaped magnetic recording medium. Another example is shown in FIG.

In the present embodiment, in addition to the above configuration, the first magnetic core half body 6b and the second magnetic core half body 6c.
And are opposed to each other through the permanent magnet 6e.

Therefore, in the structure shown in FIG. 16, the material forming the first and second magnetic core halves 6b, 6c is not a permanent magnet material, but a strong magnetic material having various kinds of soft magnetic properties or semi-hard magnetic properties. A magnetic material can be used. In addition, these first and second magnetic core halves 6b, 6c
The ferromagnetic material that constitutes the magnetic flux is supplied from the permanent magnet 6e so as not to cause significant magnetic saturation locally.
It is preferable to have a sufficiently high saturation magnetic flux density. In the present embodiment, Fe, Fe—Co alloy, Fe—Si
The soft magnetic alloy material of the system is used.

As described above, in the embodiment shown in FIG. 14, the yoke-shaped first and second magnetic core halves are uniformly arranged in the direction along the annular magnetic path of the magnetic circuit constituted by them. It is necessary to magnetize, but depending on the core shape, it may be difficult to magnetize uniformly in the direction along the annular magnetic path.

On the other hand, in the structure shown in FIG. 16, only the permanent magnets 6e are arranged along the annular magnetic path of the magnetic circuit constituted by the first magnetic core half body 6b and the second magnetic core half body 6c. Direction, that is, in the horizontal direction of the paper surface in FIG.
Since a block type rectangular parallelepiped shape can be used,
Compared to the magnetizing head illustrated in FIG. 14, it can be manufactured easily and at low cost.

In the structure of FIG. 16, the permanent magnet 6e used for a part of the annular magnetic path is preferably a residual magnetic flux density of 1.0 Tesla or more and a coercive force of 10000 Oersted (like the magnetic core in the above structure. 796kA /
m) or more is used. Further, as the permanent magnet having such characteristics, a rare earth magnet containing a material such as Nd-Fe-B or Sm-Co as a main component can be used.

(Embodiment 3) FIG. 17 shows another example of the magnetizing head of the present invention. FIG. 17 is a perspective view showing a state in which the magnetizing head 6 constituted by the permanent magnet block 6f having a substantially hexahedral shape is arranged so as to face the master information carrier 2. In the magnetizing head 6 shown in FIG. 17,
The distance D _O between the master information carrier 2 and the magnetizing head 6 at the position corresponding to the outer peripheral side of the hard disk 1 is
Greater than the separation dimension D _I of the master information carrier 2 and the magnetizing head 6 at a position corresponding to the inner peripheral side of the hard disk 1, and radially spaced dimensions of the hard disk 1 between the master information carrier 2 It is configured to change monotonously and continuously.

In order to realize such a structure, in the example shown in FIG. 17, the head main surface which is one main surface of the magnetizing head 6 facing the master information carrier 2 is processed into a taper shape. However, it may be processed into a curved surface according to the embodiment.

With such a configuration, the magnetizing head 6
Even when is composed of a substantially hexahedral permanent magnet block 6f, the magnetic field applied to the master information carrier 2 by the magnetic flux leaking from the magnetizing head 6 is:
The applied magnetic field on the outer peripheral side of the hard disk 1 can be configured to be smaller than the applied magnetic field on the inner peripheral side.

The permanent magnet block 6f is, for example, uniformly magnetized in the direction shown by the arrow E in the figure, and is provided on the master information carrier 2 by the leakage magnetic flux generated as shown by the arrow F. The obtained ferromagnetic thin film pattern can be magnetized.

As described above, in the embodiment as shown in FIG. 14, the yoke-shaped first and second magnetic core halves are arranged in the direction along the annular magnetic path of the magnetic circuit constituted by them. However, depending on the shape of the core, it may be difficult to uniformly magnetize in the direction along the annular magnetic path.

On the other hand, in the configuration shown in FIG.
Similar to the configuration shown in FIG. 6, only the permanent magnet block 6f is
The direction shown by the arrow E, that is, in FIG. 17, the magnet may be uniformly magnetized in the lateral direction of the paper surface, and the permanent magnet block 6f may have a substantially hexahedral shape. It can be manufactured more easily and cheaply than the magnetizing head.

The permanent magnet block 6f used in the structure of FIG. 17 preferably has a residual magnetic flux density of 1.0 tesla or more and a coercive force of 10000 oersteds (796 kA), like the permanent magnet 6e in the structure shown in FIG.
/ M) or more is used. Further, as the permanent magnet having such characteristics, a rare earth magnet containing a material such as Nd-Fe-B or Sm-Co as a main component can be used.

The magnetizing head 6 illustrated in FIGS. 13 to 17 exhibits the effects of the present invention when used in the transfer recording process illustrated in FIG. 9, and is illustrated in FIG. In the DC erasing process, the effect is not necessarily exhibited. Therefore, in the DC erasing process illustrated in FIG. 7, the magnetizing head having the conventional configuration illustrated in FIG. 3 can be used. That is, also in this case, the effect of the present invention can be sufficiently obtained as long as the magnetizing head having the configuration of the present invention is used in the transfer recording process illustrated in FIG.

The embodiments of the magnetizing head 6 used in the magnetic recording medium manufacturing method of the present invention have been described above. The spacing between the magnetizing head 6 and the hard disk 1 is set within an appropriate range. The magnetizing head 6
With respect to the magnetic field applied to the master information carrier 2 by the magnetic flux leaking from the hard disk 1, the applied magnetic field on the outer peripheral side of the hard disk 1 can be configured to be smaller than the applied magnetic field on the inner peripheral side. Since it is possible to sufficiently widen the allowable range of spacing between the magnetizing head 6 and the hard disk 1, the magnetizing head 6 is moved relative to the master information carrier 2 in the process of transferring and recording the information signal. Even when a certain amount of spacing variation occurs during movement, a high-quality reproduced signal can be obtained stably, and a sufficient performance margin is provided from the viewpoint of product quality assurance during mass production and improvement of production yield. It is possible to perform preformat recording having

Furthermore, in the above description, the description has been made mainly with a focus on application to a hard disk mounted in a hard disk drive or the like as a magnetic recording medium, but the present invention is not limited to this. It can be applied to a disk-shaped magnetic recording medium such as a flexible magnetic disk, and the effects of the invention can be obtained in the same manner as described above.

Regarding the information signals recorded on the magnetic recording medium, the description has been made with a focus on preformatted signals such as tracking servo signals, address information signals and reproduction clock signals. The applicable information signal is not limited to the above. For example, it is possible in principle to record various data signals, audio and video signals using the configuration of the present invention. In this case, the magnetic recording medium manufacturing method of the present invention allows mass production of soft disk media.

[0131]

As described above, according to the present invention, a pattern corresponding to an information signal on a master information carrier for a magnetic recording medium, particularly a disk-shaped magnetic recording medium such as a fixed hard disk medium, a removable hard disk medium and a large capacity flexible medium. Magnetic transfer can be performed uniformly and stably over the entire surface of the magnetic recording medium. That is, a high-density information signal can be magnetically transferred and recorded in a short time with high reliability and high productivity.

Moreover, when the information signal of the master information carrier is transcribed and recorded on the magnetic recording medium, the quality of the transcribed and recorded signal is not deteriorated, and the quality assurance of the product in mass production and the improvement of the production yield can be achieved. From the viewpoint, it is possible to provide a recording technique having a sufficiently excellent signal quality.

In particular, in performing the magnetic transfer of the pattern corresponding to the information signal on the master information carrier to the magnetic recording medium uniformly and stably over the entire surface of the magnetic recording medium, both the master information carrier and the magnetizing head are used. A great effect can be exerted by a simple improvement in which they are opposed to each other with the distance between them increasing toward the outer peripheral side.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of an example of an apparatus for carrying out signal recording on a magnetic recording medium according to a first embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a magnetizing head according to the first embodiment.

FIG. 3 is a plan view showing one main surface of the magnetizing head of Embodiment 1 facing the master information carrier (the same applies to the conventional example).

FIG. 4 is a plan view showing an example of a master information carrier used in the recording method of the present invention.

FIG. 5 is an explanatory diagram for explaining an example of an array pattern of information signals formed on a master information carrier.

FIG. 6 is a sectional view showing an example of a master information carrier according to the present invention.

FIG. 7 is a perspective view showing a situation in which a unidirectional magnetic field is applied to the hard disk in the recording method according to the present invention.

8 is a perspective view schematically showing the situation of a hard disk magnetized in one direction by the process shown in FIG.

FIG. 9 is a perspective view showing a state in which an information signal is transferred and recorded on a hard disk by the recording method according to the present invention.

10 is a perspective view schematically showing a state of a hard disk on which an information signal has been recorded by the process shown in FIG.

11 is an explanatory diagram for explaining a state of a magnetization pattern when an information signal is transferred and recorded on a hard disk by the process shown in FIG.

FIG. 12 is a schematic diagram showing a preferable recording state of preformat recording using a master information carrier in the present invention.

FIG. 13 is a perspective view showing an example of a configuration when a magnetizing head used in the recording method of the present invention is arranged so as to face a master information carrier.

FIG. 14 is a sectional view showing an example of a magnetizing head used in the recording method of the present invention.

FIG. 15 is a sectional view showing another example of a magnetizing head used in the recording method of the present invention.

FIG. 16 is a cross-sectional view showing another example of a magnetizing head used in the recording method of the present invention.

FIG. 17 is a perspective view showing another example of the configuration when the magnetizing head used in the recording method of the present invention is arranged so as to face the master information carrier.

[Explanation of symbols]

1 hard disk 2 Master information carrier 2a Signal area 6 Magnetizing head 6a winding 6b First magnetic core half 6c Second magnetic core half 6d gap 6e Permanent magnet 6f permanent magnet block 10 Non-magnetic substrate 11 Ferromagnetic thin film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI G11B 5/325 G11B 5/325 D 5/84 5/84 Z (56) Reference JP 2002-216305 (JP, A) Open 2001-297429 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 5/62-5/86 G11B 5/127 G11B 5/187 G11B 5/325

Claims (15)

(57) [Claims] 1. A magnetic head applied with a master information carrier superposed on a disk-shaped magnetic recording medium.
A magnetic field of the master information carrier through a magnetic field to magnetically transfer a pattern corresponding to an information signal on the master information carrier to the magnetic recording medium with a leakage magnetic flux from the magnetic part. A method of manufacturing a magnetic recording medium, wherein the master information carrier and the magnetizing head are provided between the two.
Face each other with the separation dimension increasing toward the outer circumference
The magnetic field applied by the magnetizing head.
When performing magnetic transfer with the recording medium being made smaller toward the outer circumference,
A method for manufacturing a magnetic recording medium, comprising: As claimed in claim 2, wherein the magnetizing head, claims characterized by using a magnetizing head comprising a first magnetic core half body and a second magnetic core halves joined to the gap formation state
Item 2. A method of manufacturing a magnetic recording medium according to Item 1 . 3. A magnetizing head in which at least one of the first magnetic core half body and the second magnetic core half body is composed of a permanent magnet is used as the magnetizing head. The method of manufacturing a magnetic recording medium according to claim 2 . 4. A magnetizing head as the magnetizing head, wherein the first magnetic core half body and the second magnetic core half body are joined together with a permanent magnet interposed therebetween. The method of manufacturing a magnetic recording medium according to claim 2, which is used. 5. A magnetizing head in which at least one of the first magnetic core half body and the second magnetic core half body has a DC excitation winding is used as the magnetizing head. The magnetic recording medium manufacturing method according to claim 2 . 6. The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetizing head is a magnetizing head made of a substantially hexahedral permanent magnet block. 7. A step of applying a DC erasing magnetic field to the magnetic recording medium to magnetize it in a fixed direction prior to the step of magnetic transfer, wherein the master information carrier is attached to the magnetized magnetic recording medium. In the step of magnetic transfer in the superposed state, by applying a magnetic field having a polarity opposite to the DC erasing magnetic field to the magnetic part of the master information carrier by using the magnetizing head, 7. The method of manufacturing a magnetic recording medium according to claim 1, wherein a pattern corresponding to an information signal is magnetically transferred onto the magnetic recording medium. 8. The DC erasing magnetic field applied to the magnetic recording medium, according to claim, characterized in that applying a substantially constant DC erasing magnetic field in the radial direction of the magnetic recording medium
7. The method for manufacturing a magnetic recording medium according to 7 . 9. The master information carrier is a disk-shaped magnetic recording medium.
The magnetic field of the master information carrier is superimposed on the recording medium.
The magnetic flux leaks from the magnetic part by magnetizing the magnetic part.
With the pattern corresponding to the information signal on the master information carrier
Made of a magnetic recording medium for magnetically transferring a core to the magnetic recording medium
Magnetizing the magnetic part of the master information carrier in the manufacturing method
A magnetic head for applying an applied magnetic field for the magnetic head , wherein the magnetic head comprises a first magnetic core half and a second magnetic core.
A half body, and the first magnetic core half body and the second magnetic core half body
Head of the magnetic core half of which faces the master information carrier
The main surface is bonded in a gap forming state, and the applied magnetic field becomes smaller toward the outer peripheral side of the magnetic recording medium.
So that the main surface of the head is the master information carrier.
Outside the magnetic recording medium
It is formed in a tapered shape or a curved shape that becomes larger toward the circumference.
Magnetization for manufacturing magnetic recording media characterized by
head. 10. The magnetic recording medium manufacturing method according to claim 9, wherein at least one of the first magnetic core half body and the second magnetic core half body is made of a permanent magnet. Magnetizing head. 11. A magnetic claim 9, wherein the the first magnetic core half body and the second magnetic core halves are joined in a state of interposing the permanent magnet therebetween Magnetizing head for manufacturing recording media. 12. The magnetic of claim 9, wherein at least one of said first magnetic core half body and the second magnetic core half is provided with a DC excitation winding Magnetizing head for manufacturing recording media. 13. A disk-shaped magnetic material for a master information carrier.
Of the master information carrier in a state of being superposed on the recording medium.
By magnetizing the magnetic unit, the leakage magnetic of the magnetic portion or al
A bundle of information signals corresponding to the information signals on the master information carrier.
Magnetic recording medium for magnetically transferring turns to the magnetic recording medium
In the manufacturing method, the magnetic portion of the master information carrier is magnetized.
A magnetic head for applying an applied magnetic field to the magnetic head, wherein the magnetic head is a substantially hexahedral permanent magnet block.
And the applied magnetic field becomes smaller toward the outer peripheral side of the magnetic recording medium.
To the hexagonal master information carrier
The main surface of the facing head is separated from the master information carrier.
The dimensions are monotonous and continuous.
It is formed in a larger tapered shape or curved shape
A magnetizing head for producing a magnetic recording medium, which is characterized in that: 14. A master information carrier having a disk-shaped magnetic field.
Of the master information carrier in a state of being superposed on the recording medium.
By magnetizing the magnetic part, the leakage magnetic field from the magnetic part
A bundle of information signals corresponding to the information signals on the master information carrier.
Magnetic transfer device for magnetically transferring turns to the magnetic recording medium
And an applied magnetic field for magnetizing the magnetic part of the master information carrier.
And a magnetic head for providing a magnetic field, the magnetic head comprising a first magnetic core half and a second magnetic core.
A half body, and the first magnetic core half body and the second magnetic core half body
Head of the magnetic core half of which faces the master information carrier
The main surface is bonded in a gap-formed state, and the applied magnetic field becomes smaller toward the outer peripheral side of the magnetic recording medium.
So that the main surface of the head is the master information carrier.
Outside the magnetic recording medium
It is formed in a tapered shape or a curved shape that becomes larger toward the circumference.
A magnetic transfer device characterized in that 15. A disk-shaped magnetic material for a master information carrier.
Of the master information carrier in a state of being superposed on the recording medium.
By magnetizing the magnetic part, the leakage magnetic field from the magnetic part
A bundle of information signals corresponding to the information signals on the master information carrier.
Magnetic transfer device for magnetically transferring turns to the magnetic recording medium
And an applied magnetic field for magnetizing the magnetic part of the master information carrier.
And a magnetizing head for providing a magnetic field, the magnetizing head being a substantially hexahedral permanent magnet block.
And the applied magnetic field becomes smaller toward the outer peripheral side of the magnetic recording medium.
To the hexagonal master information carrier
The main surface of the facing head is separated from the master information carrier.
The dimensions are monotonous and continuous.
It is formed in a larger tapered shape or curved shape
A magnetic transfer device characterized by the above.