JPH08339501A - Device for recording data and method therefor - Google Patents

Abstract

PURPOSE: To simplify the operation of writing a reproducing only data to the discoid recording medium, and to improve productivity of a discoid recording medium. CONSTITUTION: This is a data recorder for recording the data to a magnetic disk 1 on which a recessed part 14 and a projection part 13 corresponding to the data are formed, and which is coated with magnetic layers 31 and 32 along the formed recessed part 14 and projection part 13. The device is equipped with a magnetic head 2 which is opposed to the recessed part 14 and the projection part 13 and impresses a magnetic field M1 on the recessed part 14 and the projection part 13, and the magnetic field is impressed on recessed part 14 and the projection part 13 in one direction, and also a reverse magnetic field M2 is impressed on the projection part 13 in the reverse direction by the magnetic head 2. The ROM data are written by magnetizing the recessed part 14 and the projection part 13 in the different directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data recording method for recording data on a disk-shaped recording medium having a concave portion and a convex portion corresponding to the data, and a magnetic layer coated along the formed concave portion and the convex portion. The present invention relates to a recording device and a data recording method using the data recording device.

[0002]

2. Description of the Related Art Data recorded in a read-only memory (ROM) in a conventional magnetic recording medium such as a magnetic disk 1 shown in FIG. The data is written in each ROM as a recording medium by using a magnetic head for recording.

[0003]

Generally, in the field of magnetic tapes, the magnetic transfer method has become widespread. By the way, the ROM data recorded by this magnetic transfer method cannot be randomly accessed. Further, a ROM type optical disk, for example, a so-called CD-ROM disk is formed with a stamper, and a large number of optical disks can be produced at one time by using this stamper. However, since data access to an optical disk such as a CD-ROM disk is generally slower than data access to a magnetic disk, the usage of the optical disk is limited.

On the other hand, some methods have been proposed for writing data in a ROM by preforming servo pits.

For example, in a method of forming a servo pit by etching or demagnetizing a magnetic film,
Since the manufacturing process of the magnetic recording medium is complicated, it is difficult to reduce the price of each ROM.

In addition, it is known that a large amount of magnetic recording medium can be supplied at low cost by a method of forming concavo-convex servo pits by molding plastic, glass or the like.

Specifically, as described in Japanese Patent Laid-Open No. 3-228219, a method has been proposed in which two magnetic heads having different gap lengths are used to write a servo signal in an uneven servo pit. There is.

When writing ROM data to the magnetic layer deposited on the surface of this magnetic recording medium, the data recording apparatus first rotates the magnetic disk 1 in the direction shown by the arrow a as shown in A of FIG. While the magnetic gap length g
gap magnetic field M ₁ to generate giving direct recording current to the magnetic head 2a of _a, is applied to the magnetic disk 1, the recess 1
4 and the entire surface of the magnetic layer 12 of the convex portion 13 are magnetized in one direction, that is, the direction indicated by the arrow m ₁ .

Next, as shown in FIG. _15B , while rotating the magnetic disk 1 in the direction indicated by the arrow a, a DC recording current is applied to the magnetic head 2b having a magnetic gap length g _b ,
The generated gap magnetic field M ₂ is applied to the magnetic layer of the convex portion 13 of the magnetic disk 1, and the convex portion 13 is in the direction opposite to the direction indicated by the arrow m ₁ , that is, in the direction indicated by the arrow m _2. Magnetize sequentially.

According to the procedure described above, the convex portion 13 and the concave portion 14 are magnetized in opposite directions, and data is written in the ROM. However, in this method, it is necessary to use two magnetic heads for writing a signal, and the use means for using these two magnetic heads is complicated, which may cause great difficulty.

Therefore, the present invention has been made in view of the above-mentioned circumstances, and data for which reproduction-only data can be written in a disk-shaped recording medium can be simplified and productivity of the disk-shaped recording medium can be improved. An object is to provide a recording device and a data recording method using the data recording device.

[0012]

In order to solve the above-mentioned problems, a data recording device of the present invention is provided with recesses and protrusions corresponding to data, and the magnetic layer is formed along the recesses and protrusions formed. In a data recording device for recording data on a disk-shaped recording medium to which is adhered, a magnetic field generating means is provided which is opposed to the concave portion and the convex portion and which applies a magnetic field to the concave portion and the convex portion. The magnetic field generating means applies a magnetic field in one direction to the concave portion and the convex portion, and applies a reverse magnetic field in the opposite direction to the convex portion.

Further, in order to solve the above-mentioned problems, the data recording apparatus of the present invention is provided with concave portions and convex portions corresponding to data, and a magnetic layer is deposited along the formed concave portions and convex portions. In a data recording device for recording data on a disc-shaped recording medium, a magnet that faces the recess and the projection and applies a magnetic field in one direction to the recess and the projection, and A magnetic field generating means for applying a magnetic field in a direction opposite to the direction of the magnetic field is provided.

Further, it is possible that the magnet applies a magnetic field to the magnetic layers of a plurality of disk-shaped recording media at the same time.

Further, in the data recording method of the present invention, in order to solve the above-mentioned problems, concave portions and convex portions corresponding to data are formed, and a magnetic layer is deposited along the formed concave portions and convex portions. In a data recording method for recording data on a disk-shaped recording medium, a magnetic field generated by applying a DC recording current to a magnetic head facing the magnetic layer is applied to the magnetic layer to magnetize the magnetic layer in one direction. One magnetizing process,
A magnetic field having a direction opposite to the direct current recording current applied to the magnetic head in the first magnetization step and applying a current smaller than the direct current recording current to the magnetic head generates a reversal magnetic field and the magnetic layer of the convex portion. And a second magnetization step of reversely magnetizing the magnetic layer of the convex portion.

Further, in order to solve the above-mentioned problems, the data recording method of the present invention forms concave portions and convex portions corresponding to data, and deposits a magnetic layer along the formed concave portions and convex portions. In a data recording method for recording data on a disk-shaped recording medium, a magnetic field generated by applying a DC recording current to a magnetic head facing the magnetic layer is applied to the magnetic layer to magnetize the magnetic layer in one direction. One magnetizing process,
A reversal magnetization that gives a current in a direction opposite to the DC recording current applied to the magnetic head in the first magnetization step is generated from the position of the magnetic head with respect to the magnetic layer in the first magnetization step. Is applied to the magnetic layer of the convex portion from a position far away from the magnetic layer, and the second magnetic step of reversely magnetizing the magnetic layer of the convex portion is performed.

Further, in order to solve the above-mentioned problems, the data recording method of the present invention is provided with recesses and protrusions corresponding to data, and a magnetic layer is deposited along the recesses and protrusions formed. In the data recording method for recording data on a disk-shaped recording medium, two magnets are arranged so as to sandwich the disk-shaped recording medium, and magnetic poles different from each other are made to face each other, and the centers of the facing surfaces are displaced from each other by a predetermined distance. ,
To apply a magnetic field generated between the two magnets to the magnetic layer to magnetize the magnetic layer in one direction, and to reverse magnetize the magnetic layer magnetized in the first magnetizing step. The second magnetic process for applying a magnetic field to the magnetic layer of the convex portion to reverse magnetize the magnetic layer of the convex portion by the magnetic field generating means for generating the magnetic field.

The first magnetizing step may be a step of magnetizing the magnetic layers of a plurality of disk-shaped recording media at the same time.

[0019]

According to the data recording apparatus of the present invention, the magnetic field generating means applies a magnetic field to the magnetic layers of the concave and convex portions of the disk-shaped recording medium to move the magnetic layers of the concave and convex portions in one direction. The magnetic layer is magnetized, and a reversal magnetic field in the opposite direction is applied to the convex portion to reverse magnetize the magnetic layer of the convex portion.

According to the data recording apparatus of the present invention,
The magnet applies a magnetic field to the magnetic layers of the concave and convex portions of the disk-shaped recording medium to magnetize the magnetic layers of the concave and convex portions in one direction, and the magnetic field generating means reverses the direction of the convex portions. Is applied to reversely magnetize the magnetic layer of the convex portion.

According to the data recording method of the present invention,
In the first magnetizing step, a magnetic field generated by applying a DC recording current to the magnetic head is applied to the magnetic layer of the disk-shaped recording medium to magnetize the magnetic layer in one direction. In the second magnetizing step, the direction is opposite to the direct current recording current applied to the magnetic head in the first magnetizing step, and a current smaller than the direct current recording current is applied to the magnetic head to cause inversion. A magnetic field is applied to the magnetic layer of the convex portion to reverse magnetize the magnetic layer of the convex portion.

According to the data recording method of the present invention,
In the first magnetizing step, a magnetic field generated by applying a DC recording current to the magnetic head is applied to the magnetic layer of the disk-shaped recording medium to magnetize the magnetic layer in one direction. In the second magnetization step, a reversal magnetic field is generated by applying a current in a direction opposite to the DC recording current applied to the magnetic head in the first magnetization step, and the generated magnetic field in the first magnetization step A voltage is applied to the magnetic layer of the convex portion from a position distant from the position of the magnetic head with respect to the layer to reverse-magnetize the magnetic layer of the convex portion.

According to the data recording method of the present invention,
In the first magnetizing step, two magnets are arranged with the disc-shaped recording medium sandwiched therebetween, and magnetic poles different from each other are made to face each other and the centers of the facing surfaces are displaced from each other by a predetermined distance.
A magnetic field generated between the two magnets is applied to the magnetic layer to magnetize the magnetic layer in one direction. In the second magnetizing step,
A magnetic field is applied to the magnetic layer of the convex portion by magnetic field generating means for generating a magnetic field for reversing the magnetization of the magnetic layer magnetized in the first magnetizing step, and the magnetic layer of the convex portion is changed to the above-mentioned magnetic layer. The magnetization is performed in the direction opposite to the direction magnetized in the first magnetizing step, that is, reverse magnetization.

[0024]

Embodiments of the data recording apparatus and the data recording method of the present invention will be described below with reference to the drawings.

In the following embodiments, a case will be described as an example in which read-only memory (ROM) data is written to a magnetic disk having concavo-convex portions formed concentrically in advance.

The magnetic disk is, as shown in FIG.
It has a so-called data track 17, which is a concentric area for writing ROM data.

As shown in FIG. 2, the data track 17 has a length W in the track width direction of about 5 μm and a length L along the running direction of the magnetic disk 1 of 0.7 to 2.9 μm.
The rectangular convex portion 13 formed to have a size is a portion formed in a pattern corresponding to the ROM data to be recorded.

The pattern composed of the convex portions 13 and the concave portions 14 is formed by the reactive ion etching method, the so-called RIE method,
The photopolymer method, so-called glass 2P method, is applied to the magnetic disk 1 and formed on a non-magnetic support having a thickness of 0.9 mm, for example. The convex portion 13 and the concave portion 14
As the depth of the pattern composed of, for example, a depth of 0.2 μm
What is used.

The magnetic disk 1 has a thickness of 15
0 nm chromium underlayer and 30 nm thick Co-Pt
And a carbon protective film having a thickness of 10 nm are sequentially deposited by the sputtering method.

In each embodiment of the data recording method described below, for example, as shown in FIG. 2, the convex portion 13 is magnetized in the direction shown by the arrow m _s , and the concave portion 14 is magnetized in the direction opposite to the arrow m _s. The ROM data is written by magnetizing in the direction indicated by the arrow m _t and by making the directions of magnetization opposite to each other.

Here, in the first embodiment of the data recording apparatus, as shown in FIGS. 3A and 3B, for example, a concave portion 14 and a convex portion 13 corresponding to data are formed, and the formed concave portion 14 and In a data recording device for recording data on a magnetic disk 1 which is a disk-shaped recording medium having magnetic layers 31 and 32 adhered along the convex portion 13, the concave portion 14 is opposed to the concave portion 14 and the convex portion 13 in the data recording device. And the convex portion 13
Is provided with a magnetic head 2 as a magnetic field generating means for applying a magnetic field M ₁ to the concave portion 14 and the convex portion 13, and the magnetic field generating means applies a magnetic field in one direction to the concave portion 14 and the convex portion 13.
The reverse magnetic field M ₂ is applied to the convex portion 13 in the opposite direction.

Although not shown, a control means for controlling the above-mentioned operation is provided, and in the embodiment of the data recording method described below, the operation of the magnetic field generating means according to the operation of the control means is concretely described. An example will be described.

In the first embodiment of the data recording method showing the control contents of the control means in the first embodiment of the data recording apparatus, as shown in FIGS. The convex portion 13 is formed on the non-magnetic support 11, and the magnetic layer 3 is formed along the formed concave portion 14 and convex portion 13.
In a data recording method for recording ROM data on a disk-shaped recording medium on which the magnetic layers 1 and 32 are adhered, as shown in FIG. 3A, the magnetic head 2 facing the magnetic layers 31 and 32.
A magnetic field M ₁ generated by applying a DC recording current to the magnetic layer 3
₁ and 32 to magnetize the magnetic layers 31 and 32 in one direction, that is, in the arrow m ₁ , and as shown in FIG. Two
In the opposite direction to the DC recording current given to
A reversal magnetic field M ₂ is applied to the magnetic head 2 to generate a current smaller than the DC recording current, and is applied to the magnetic layer 32 of the convex portion 13 to reverse magnetize the magnetic layer 32 of the convex portion 13. And a magnetizing step.

In the first magnetization step of the above embodiment of the data recording method, in the magnetic head 2, the magnetic gap G filled with the gap material has the gap length g ₀ and the magnetic layer 32 of the convex portion 13 is different from the magnetic layer 32. And face each other at a position separated by a predetermined distance d. This distance d is a value set according to the magnitude of the DC recording current or the first DC current supplied to the magnetic head 2 in the first magnetization step, and the magnetic field M
Sufficient value is taken to apply ₁ to both magnetic layers 31 and 32.

Therefore, by applying the magnetic field M ₁ to the magnetic layers 31 and 32 while rotating the magnetic disk 1 in the direction indicated by the arrow a and scanning the magnetic disk 1 with the magnetic head 2, The magnetic layers 31 and 32 corresponding to the track width of the magnetic head 2 are sequentially magnetized in the direction indicated by the arrow m ₁ .

Further, in the second magnetizing step, the DC recording current supplied to the magnetic head 2 is reduced in the opposite direction to the DC recording current in the first magnetizing step, whereby the magnetic field from the magnetic head 2 is reduced. A weak reversal magnetic field M ₂ is generated in the opposite direction to M ₁ . The magnetic head 2 is the same magnetic head as the magnetic head 2 used in the first magnetizing step, and is the same as the magnetic head 32 in the first magnetizing step from the position separated by the distance d from the magnetic layer 32. Then, the reversal magnetic field M ₂ is applied. The DC recording current or the second DC current supplied to the magnetic head 2 in the second magnetization step applies the reversal magnetic field M ₂ to only the magnetic layer 32 of the convex portion 13 from a position separated by the distance d. The size is such that it is applied.

Therefore, when the reversal magnetic field M _{2 is applied} to the magnetic disk 1 by rotating the magnetic disk 1 in the direction indicated by the arrow a while scanning the magnetic disk 1 with the magnetic head 2, the magnetic force of the magnetic field strength causes the magnetism of the protrusions 13 to increase. Since the magnetic layer 31 is applied to the layer 32 but not to the magnetic layer 31 of the recess 14, the magnetic layer 32 can be reversed-magnetized.

Here, for example, if the gap length g ₀ is 0.
When a magnetic head having a track width of 4 μm, a track width of 100 μm and a coil winding number of 28 is used and the first DC current is 60 mA, the second DC current (mA) is used.
And the reproduction output (dBm) have a curve 41 as shown in FIG. The relative speed between the magnetic head and the magnetic disk 1 is 6 m / s, and the distance d is 0.13 μm.

According to the curve 41, when the second DC current has a magnitude of about 7 to 10 mA, the reproduction output takes a maximum value, and the reproduction output generally has a sufficient S / N ratio for servo control. ROM recorded on the magnetic layers 31 and 32 by
It can be seen that the reproduction output is large enough to reproduce the data.

Further, for example, the gap length g ₀ is 0.4
When a magnetic head having a track width of 10 μm and a track width of 10 μm is used and the first direct current is set to 60 mA, a curve having the same tendency as the curve 41 can be obtained. In particular, the second direct current is set to 8 mA and the ROM is set to 8 mA. When a magnetic disk on which data was recorded was reproduced by a reproducing magnetic head, it was found that the ROM data can be reproduced at an S / N ratio necessary for signal processing, which is processing after reading the ROM data. .

The data recording apparatus of the first embodiment may have the same configuration, and the control content of the control means may be the same as that of the second embodiment of the data recording method shown below.

Therefore, in the second embodiment of the above data recording method, as shown in FIGS. 5A and 5B, the concave portion 14 and the convex portion 13 corresponding to the data are formed on the non-magnetic support 11,
Along the formed concave portion 14 and convex portion 13, the magnetic layer 31,
In a data recording method for recording data on a disk-shaped recording medium to which 32 is attached, as shown in FIG. 5A, a magnetic field generated by applying a DC recording current to the magnetic head 2 facing the magnetic layers 31 and 32. M ₁ is applied to the magnetic layers 31 and 32 to move the magnetic layers 31 and 32 in one direction, that is, the arrow m.
_In the first magnetization step of magnetizing in the direction shown in FIG. 1 and in the first magnetization step as shown in FIG.
The reversal magnetic field M ₂ that is generated by applying a current in the direction opposite to the DC recording current applied to the magnetic head 2 is separated from the position of the magnetic head 2 with respect to the magnetic layer 32 of the convex portion 13 in the first magnetization step. Position, that is, when the distance between the magnetic head 2 and the magnetic layer 32 in the first magnetization step is a distance d ₁ and the distance between the magnetic head 2 and the magnetic layer 32 in the second magnetization step is a distance d ₂ , From the position where the distance d ₁ <distance d ₂ is applied to the magnetic layer 32 of the convex portion 13, the convex portion 1
And a second magnetization step of reversing the magnetization of the third magnetic layer 32.

In the first magnetizing step of the second embodiment of the data recording method, the magnetic head 2 has a magnetic gap filled with a gap material, like the magnetic head 2 used in the first embodiment. G has a gap length g ₀ . The distance d ₁ is a value set according to the magnitude of the DC recording current or the first DC current supplied to the magnetic head 2 in the first magnetizing step, and the first DC current is The value is sufficient to apply the magnetic field M ₁ generated by being supplied to the magnetic head 2 to both the magnetic layers 31 and 32.

Therefore, as shown in FIG. 5A, the magnetic field M ₁ is applied to the magnetic layers 31 and 32 while rotating the magnetic disk 1 in the direction shown by the arrow a, whereby the magnetic layers 31 and 32 are applied. Is magnetized in the direction indicated by arrow m ₁ .

Further, in the second magnetizing step, as shown in FIG.
As indicated by B, the reversal magnetic field M ₂ generated by supplying a second DC current having the same magnitude as the first DC current but in the opposite direction to the magnetic head 2 is generated at a distance d larger than the distance d _{1. 2}
When the magnetic field is applied to the magnetic disk 1 with only the distance, the reversal magnetic field M ₂ is applied to the magnetic layer 32 of the convex portion 13 but not to the magnetic layer 31 of the concave portion 14, and therefore only the magnetic layer 32 is reverse-magnetized. can do.

For example, in the first magnetizing step, the gap length g ₀ of the magnetic head is 0.4 μm, the track width is 100 μm, the number of coil turns is 28, and the first DC current is 60 mA. The distance d ₁ is 0.13
μm, and the number of rotations of the magnetic disk at the time of recording the ROM data is 3600 rotations per minute (rpm). In the second magnetizing step, the distance d _{2 is set} to 1.0 μm, and the rotation speed of the magnetic disk is increased to 9400 rpm. When the magnetic disk on which the ROM data has been recorded in this way is reproduced by the reproducing magnetic head, the ROM data is reproduced at the S / N ratio necessary for signal processing, which is the processing after reading the ROM data. I found that I could do it.

In the magnetic head, the gap length g ₀ is 0.3 μm and the track width is 10 μm.
It was found that even for a magnetic disk on which data was recorded with the first direct current of 50 mA, a reproduction signal with a sufficient S / N ratio was read when the reproduction was performed by the reproduction magnetic head.

According to the first embodiment of the data recording device and the first and second embodiments of the data recording method, the magnetic disk having the concave and convex portions formed on the surface and the magnetic layer deposited thereon Conventionally, when recording ROM data on a disk, two types of magnetic heads having different gap lengths were used, so it was necessary to provide a space and a process for exchanging the magnetic head to be used. The ROM data can be written on the magnetic disk by using one magnetic head, and the space and the process for exchanging the magnetic head can be deleted.
Writing M data is simplified and productivity is improved.

In the second embodiment of the data recording apparatus, as shown in FIGS. 6A and 6B, for example, the concave portion 14 and the convex portion 13 corresponding to the data are formed, and the formed concave portion 1 is formed.
In the data recording device for recording data on the magnetic disk 1 which is a disk-shaped recording medium having the magnetic layers 31 and 32 adhered along with the concave portions 14 and the convex portions 13, Permanent magnets 21 and 22 for applying a magnetic flux M ₁₁ in one direction to the concave portion 14 and the convex portion 13.
And a magnetic head 2 as magnetic field generating means for applying a reversing magnetic field M ₂ to the convex portion 13 in the direction opposite to the direction of the magnetic field.

Although not shown, a holding body for holding the above two permanent magnets as described above and a control means for controlling the above operation are provided, and the following data recording method is carried out. A specific example of the operation of the permanent magnets 21 and 22 and the magnetic field generating means according to the operation of the control means will be described by way of example.

The third embodiment of the data recording method showing the control contents of the control means in the second embodiment of the data recording apparatus corresponds to data as shown in FIGS. 6A and 6B. In the data recording method for recording data on the disk-shaped recording medium on which the concave portions 31 and the convex portions 32 are formed, and the magnetic layers 31 and 32 are adhered along the formed concave portions 14 and the convex portions 13, As shown in FIG. 2, the two permanent magnets 21 and 22 are arranged so as to sandwich the disk-shaped recording medium, and different magnetic poles are made to face each other and the centers of the facing surfaces are displaced from each other by a predetermined distance. Two
The magnetic flux M ₁₁ generated between the magnetic layers 1 and 22 is applied to the magnetic layers 31 and 32.
6 is applied to the magnetic layers 31 and 32 to magnetize the magnetic layers 31 and 32 in one direction, that is, the direction indicated by the arrow m ₁ .
As shown in FIG. 5, in the magnetic head 2 which is the magnetic field generating means for generating the reversal magnetic field M ₂ for reversing the magnetization of the magnetic layer 32 magnetized in the first magnetizing step, the magnetic layer 32 of the convex portion 13 is formed. The reversal magnetic field M ₂ is applied to the convex portion 13
Second magnetization step of reversely magnetizing the magnetic layer 32.

In the first magnetizing step of the third embodiment, as shown in FIG. 7, the permanent magnets 21 and 22 have the same length as the radius of the magnetic disk 1 and have different polarities. Thus, the magnetic disks 1 are opposed to each other. Further, as shown in A of FIG. 6, the permanent magnets 21 and 22 are arranged at positions where the facing surfaces do not coincide with each other.
By applying the magnetic flux M ₁₁ between them by rotating the magnetic disk 1 in the direction shown by the arrow a and scanning the magnetic disk 1 only once, the magnetic layers 31 and 32 are collectively unidirectionally, that is, the arrow. Magnetize in the direction indicated by m ₁ .

In the second magnetization step, the reversal magnetic field M ₂ is applied by using the magnetic head 2 in which the magnetic gap G filled with the gap material has a gap length g _{0 of} 0.4 μm and a track width of 100 μm. By generating and applying the reversal magnetic field M ₂ to the magnetic layer 32 of the convex portion 13 from a position separated by a predetermined distance, the magnetic layer 32 of the convex portion 13 is generated.
Only is reverse magnetized in the direction indicated by the arrow m ₂ , which is the opposite direction of the arrow m ₁ .

Here, as shown in FIG. 6A and FIG. 7, the magnetic disk 1 when the permanent magnets 21 and 22 are arranged.
The distribution of the magnetic flux density on the surface of is obtained by static magnetic field analysis as shown in A and B of FIG.

Now, the permanent magnets 21 and 22 will be described.

FIG. 8A shows a model of the first embodiment of the above data recording method in which permanent magnets 21 'and 22' having the same shape as the permanent magnets 21 and 22 are arranged at predetermined positions. FIG. Here, the direction along the circumferential direction of the magnetic disk 1 is the x axis, and the direction away from the surface of the magnetic disk 1 is the z axis. The permanent magnet 21
The length in the x-axis direction of ′ and 22 ′ is 6 mm, and the length in the z-axis direction is 20 mm.

FIG. 8B shows z between the magnetic pole end faces of both permanent magnets.
With the axial distance z ₀ of 6 mm, the permanent magnet 21
It is a figure which shows the distribution of the magnetic flux density of the x component of the x-axis direction in the said model when the symmetry point of 'and 22' is made into an origin. At the position where each magnetic flux density is observed, the value of x in the right direction from the origin in FIG. 8A is positive, and the value of x in the left direction is negative.

According to FIG. 8B, the magnetic flux density takes the maximum in the rightward direction on the z-axis side of each permanent magnet 21 ', 22', and the outer side of each permanent magnet 21 ', 22'. Maximum leftward near the side. Further, the maximum magnetic flux density in the leftward direction is approximately 1/3 of the maximum magnetic flux density in the rightward direction. In addition, this static magnetic field analysis is based on the assumption that the magnetic flux density in the magnetic flux direction of the magnet is 1.38 [T].

Further, in the above model, the maximum magnetic flux density in the rightward direction is 0.69 [T]. Therefore, assuming that the relative permeability μ of air is 1, the magnitude of the magnetic field generated here is It becomes 6900 Oersted (Oe).

Therefore, when writing ROM data to a magnetic disk coated with a magnetic layer having a coercive force of, for example, 1900 [Oe], the permanent magnets 21 and 22 used in the first magnetizing step ((( 1.38 [T]) × 10
⁴ [Oe · T ^-1 ]) x 1900 [Oe] / (6900
[Oe] × 10 ⁴ [Oe · T ⁻¹ ]) = 0.38 [T] It is preferable to use a permanent magnet that generates a magnetic flux density of about or more.
The upper limit of the permanent magnet used in this first magnetizing step is
It is determined within a range in which the magnetic layer is not magnetized by the opposite magnetic field generated by the opposite poles of the permanent magnets 21 and 22.

The second embodiment of the data recording device can also be used as a data recording device for simultaneously recording on a plurality of magnetic disks.

Therefore, as shown in FIG. 9, the permanent magnet 2 is used in the first magnetizing step when recording on a plurality of magnetic disks.
3 and 24 are opposed to each other with a housing-shaped drive device 30 incorporating a plurality of magnetic disks 1 so as to have polarities different from each other. Furthermore, the permanent magnets 23 and 24 are
The permanent magnets 23, 2 are arranged at positions where the facing surfaces do not match.
By applying the magnetic flux between the magnetic disks 4 while rotating the magnetic disks 1, the entire surface of the magnetic layer adhered to the concave portions and the convex portions on the magnetic disks 1 is magnetized in one direction.

In the second magnetizing step, a reversal magnetic field is generated by using a magnetic head having a magnetic gap G filled with a gap material having a gap length g _{0 of,} for example, 0.4 μm and a track width of 10 μm. By applying the reversal magnetic field to the magnetic layer of the convex portion from a position separated by a predetermined distance, only the magnetic layer of the convex portion is inversely magnetized.

In FIG. 9, the permanent magnets 23 and 24 are arranged so that the magnetic poles different from each other face each other.
The magnetic disks 1 are arranged at positions displaced from each other along the circumferential direction of the magnetic disk 1 with a distance of 0 between them and at a distance d _{4 of,} for example, 3 mm. Further, the drive device 30 has a thickness s of, for example, 10 mm, and a plurality of, for example, four magnetic disks 1 can be incorporated therein.

As the permanent magnets 23 and 24, 1.
A magnetic field of 38 × 10 ⁴ [Oe] is generated, for example, S
An mCo-based permanent magnet is used. FIG. 10 shows the distribution of the magnetic flux density of the x component in the x-axis direction obtained by performing the static magnetic field analysis with the circumferential direction of the magnetic disk 1 as the x-axis using this SmCo-based permanent magnet.

In FIG. 10, as in FIG. 8B, the magnetic flux density takes the maximum in the right direction on the z-axis side of the permanent magnets 23, 24, and the permanent magnets 23, 24 are also made.
Takes the maximum in the leftward direction near the outer side surface of. Further, the maximum magnetic flux density in the rightward direction is 0.162 [T], so that when the relative permeability μ of air is 1, the magnitude of the magnetic field generated here is 1620 [Oe].

According to FIG. 10, a permanent magnet which generates a magnetic field of 1.38 × 10 ⁴ is sufficient for recording on a magnetic disk coated with a magnetic layer having a coercive force of about 1600 [Oe]. It can be seen that it is a permanent magnet that generates a magnetic field of various strengths.

When the control means is caused to perform the control shown in the third embodiment of the data recording method, a magnetic head is used as the magnetic field generating means used in the second magnetizing step. However, a permanent magnet can be used as the magnetic field generating means.

Then, referring to FIGS. 11A and 11B, a modification in which a permanent magnet is used as the magnetic field generating means in the data recording method of the third embodiment will be described.

In the modification of the third embodiment of the above data recording method, the concave portions 14 and the convex portions 13 corresponding to the data are formed, and the magnetic layer 3 is formed along the formed concave portions 14 and the convex portions 13.
In a data recording method for recording data on a magnetic disk 1 which is a disk-shaped recording medium to which 1 and 32 are attached,
As shown in FIG. 11A, the two permanent magnets 21, 22
Are arranged with the disc-shaped recording medium sandwiched between them, and different magnetic poles are made to face each other and the centers of the facing surfaces are offset from each other by a predetermined distance, and the magnetic flux M ₁₁ generated between the two permanent magnets 21 and 22 is described above. A first magnetization step of applying the magnetic layers 31 and 32 to magnetize the magnetic layers 31 and 32 in one direction, that is, the direction indicated by the arrow m _1, and the first magnetization step as shown in FIG. 11B. A reversal magnetic field M ₂ is applied to the magnetic layer 32 of the convex portion 13 by a U-shaped permanent magnet 23 as a magnetic field generating means for generating a magnetic field for reversing the magnetization of the magnetic layer magnetized in the process. , The magnetic layer 32 of the convex portion 13
And a second magnetization step for reversing magnetization.

In a modification of the third embodiment of the data recording method, the permanent magnet 2 is used in the first magnetizing step.
Similar to the first magnetizing step in the third embodiment, as shown in FIG. 7, the reference numerals 1 and 22 have the same length as the radius of the magnetic disk 1 and are magnetized so that their polarities are different from each other. They are opposed to each other with the disc 1 in between. Further, as shown in A of FIG. 11, the permanent magnets 21 and 22 are arranged at positions where the facing surfaces do not coincide with each other, and the magnetic flux M between the permanent magnets 21 and 22 is increased.
₁₁ , rotate the magnetic disk 1 in the direction shown by the arrow a,
By scanning the magnetic disk 1 once and applying it,
The entire surfaces of the magnetic layers 31, 32 are collectively magnetized in one direction, that is, the direction indicated by the arrow m ₁ .

The permanent magnets 21 and 22 used in the first magnetizing step have the same shape and arrangement as the permanent magnets shown in FIGS. 6 to 8 and generate magnetic fields of the same strength. .

In the second magnetizing step, a reversal magnetic field M ₂ is generated using the U-shaped permanent magnet 25,
The switching field of M ₂ from a distance by a predetermined distance by applying the magnetic layer 32 of the convex portion 13, an arrow m ₂ only magnetic layer 32 of the convex portion 13 to the arrow m ₁ in the opposite direction Reverse magnetization is performed in the direction shown in.

Here, the permanent magnet 25 will be described.

FIG. 12A is a view showing a state in which a permanent magnet 25 'having the same shape as the permanent magnet 25 is viewed from one side.

In FIG. 12A, the rotation direction of the magnetic disk is x-axis, and the direction perpendicular to the recording surface of the magnetic disk is z-axis. The permanent magnet 25 'has a width w ₁ and a width w ₂ of each magnetic pole end of 6 mm, a distance x ₁ between the magnetic poles of 2 mm, and a length L _z in the z-axis direction of 20 mm. is there.

FIG. 12B shows the size shown in FIG. 12A, and the magnetic flux density in the magnetic flux direction is 1.
Using the permanent magnet 25 'of 38 [T], the distance z ₁ from the magnetic pole to the recording surface of the magnetic disk was set to 6 mm, and the static magnetic field analysis described above was performed and x in the x-axis direction was obtained.
It is a figure which shows the distribution of the magnetic flux density of a component.

According to FIG. 12B, the magnetic flux density has a maximum in the rightward direction on the z-axis side of each magnetic pole, and has a maximum in the leftward direction near the outer side surface of each magnetic pole. Moreover, since the maximum magnetic flux density in the right direction is 0.207 [T], assuming that the relative permeability μ of air is 1, the magnitude of the magnetic field generated here is 2070 [Oe].

Here, in the first embodiment of the data recording method, particularly as shown in FIG. 4, the second DC current is set to about 1/5 of the first DC current. If the strength of the magnetic field generated in the second magnetization step is set to about 1/5 of the strength of the magnetic field generated in the first first magnetization step, the read ROM data is written to the read head. It is shown that the reproduction output at the time of reproduction takes the maximum value.

That is, when the magnetic layer 32 of the convex portion 13 is inversely magnetized, when a magnetic field having a magnitude of about ⅕ of the strength of the magnetic field that magnetizes all the magnetic layers 31 and 32 is applied, reproduction is performed. ROM data that maximizes output can be written.

Therefore, when writing ROM data of a magnetic disk to which a magnetic layer having a coercive force of, for example, 1900 [Oe] is written, the strength of the applied magnetic field required in the second magnetization step of the above modification is 1900 x (1/5) = 38
It becomes 0 [Oe]. Then, as the permanent magnet 25,
13800 [Oe] x 380 [Oe] / 2070 [O
e] = 2533 [Oe], a permanent magnet that generates a magnetic field, that is, the generated magnetic flux density is 0.2533.
It is understood that the permanent magnet of [T] may be used.

In the data recording apparatus adopting the modified example of the third embodiment of the above data recording method, the permanent magnets 21 and 2 are used.
The magnetic layers 31 and 32 of the magnetic disk 1 can be formed by simply disposing the magnetic disks 2 and 25 at predetermined positions and rotating them on the magnetic disk 1.
Can be magnetized, and only the magnetic layer 32 of the convex portion 13 can be inversely magnetized, that is, ROM data can be written, and the work of writing ROM data is simplified and the productivity is improved.

Furthermore, in the above modification, an example in which a U-shaped permanent magnet such as the permanent magnet 25 is used has been described, but similarly when two bar magnets are used, in the second magnetization step as well. Only the magnetic layer 32 of the convex portion 13 can be inversely magnetized. The polarities of the two bar magnets are arranged so as to be opposite to those of the permanent magnets 21 and 22 used in the first magnetizing step. The two bar magnets have a length equal to or longer than the radius of the magnetic disk 1.

Also by this, it becomes possible to write the ROM data in the ordinary drive device, which is impossible by the conventional method, so that the data recording device can be simplified and the productivity can be improved.

By the way, in the third embodiment of the data recording method and its modification, the two permanent magnets are not used in the first magnetizing step, and only a single permanent magnet is magnetized in one direction. It's difficult.

Therefore, A and B of FIG. 13 and A of FIG.
B shows the distribution of the magnetic flux density of the x component obtained by performing the static magnetic field analysis on the periphery of the single rod-shaped permanent magnet 26.

FIG. 13A shows a state in which the longitudinal direction of the permanent magnet 26 is the x axis and the axis passing through the boundary between the S pole and the N pole of the permanent magnet 26 is the z axis.

In FIG. 13B, the x-axis is the direction along the circumferential direction of the magnetic disk for recording ROM data, and the z-axis is the direction perpendicular to the recording surface of the magnetic disk. Distance z from the side surface of the permanent magnet 26
₃ shows the distribution of the magnetic flux density in the x-axis direction on the N-pole side when ₃ is 0.1 μm and the strength of the magnetic field generated from the permanent magnet 26 is 13800 [Oe]. Further, the magnetic flux density is positive in the z-axis direction, that is, the rightward component in FIG. 13A, and the leftward component is negative.

According to FIG. 13B, it is shown that the magnetic flux density becomes negative in the portion slightly below the magnetic pole end surface of the permanent magnet 26 and becomes positive in the outer portion. Further, although the distribution of the magnetic flux density on the S pole side is not shown, it is considered that a curve symmetrical to the distribution of the magnetic flux density on the N pole side and the z axis can be obtained. Therefore, since the magnetic flux density, that is, the direction of the magnetic field differs depending on the relative position to the permanent magnet 26, it is shown that a uniform magnetic field cannot be applied in one direction in the first magnetization step.

Further, FIG. 14A shows a state in which the direction perpendicular to the longitudinal direction of the permanent magnet 26 is the x axis and the longitudinal direction is the z axis.

Similar to FIG. 13B, in FIG. 14B, the x-axis is the direction along the circumferential direction of the magnetic disk for recording ROM data, and the z-axis is perpendicular to the recording surface of the magnetic disk. Direction of the permanent magnet 26,
The separation distance z ₄ from the end surface on the pole side is 0.1 μm, and the strength of the magnetic field generated from the permanent magnet 26 is 13800.
The distribution of the magnetic flux density of the x component in the x-axis direction on the one N-pole side obtained by bisecting the permanent magnet 26 along the z-axis when [Oe] is shown. Further, the magnetic flux density is positive in the z-axis direction, that is, the rightward component in FIG. 13A, and the leftward component is negative.

According to FIG. 14B, in the magnetic flux density, the direction of the magnetic field is uniform in the positive x direction. Also,
Although not shown, the distribution of the magnetic flux density on the other N-pole side divided into two parts is considered to be a curve symmetrical to the z-axis in the opposite direction to the distribution of the magnetic flux density in B of FIG. To be Therefore, it is shown that the direction of the magnetic field differs depending on the relative position with respect to the permanent magnet 26, and thus it is also impossible to apply a uniform magnetic field in one direction in the first magnetization step.

Therefore, in order to solve the above problems,
As shown in the third embodiment of the data recording method and its modification, the two permanent magnets are arranged so as to face each other with the magnetic pole ends of opposite polarities being slightly offset from each other with the magnetic disk for recording ROM data interposed therebetween. Thereby, in the first magnetization step, the magnetization directions of the magnetic layers 31 and 32 can be reliably aligned in the same direction.

[0094]

As described above, according to the data recording apparatus of the present invention, since the read-only data is written on the disk-shaped recording medium by the single magnetic head, the number of magnetic heads can be reduced as compared with the conventional one. Therefore, it is possible to reduce the number of parts and the mounting space, and further it is possible to improve the productivity of the disc-shaped recording medium in which the read-only data is recorded.

According to the data recording method of the present invention,
Since the write-only data is written to the disk-shaped recording medium with a single magnetic head, the step of replacing the magnetic head in the conventional data recording method can be eliminated, and the write-only data write operation is simplified. The productivity of the disc-shaped recording medium is improved.

Further, according to the data recording apparatus and the data recording method of the present invention, when the read-only data is recorded on the disc-shaped recording medium, the magnetic field is applied to the disc-shaped recording medium by using the permanent magnet. Since the disc-shaped recording medium needs to be scanned only once, the read-only data can be written in the disc-shaped recording medium by adding a simple configuration to the ordinary data recording device and the data recording method. It is possible to improve the productivity of the disc-shaped recording medium.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a magnetic disk used in this embodiment.

FIG. 2 is a diagram showing the relationship between the concavo-convex pattern formed on the magnetic disk and the direction of written magnetization.

FIG. 3 is a diagram illustrating a configuration of a first embodiment of a data recording apparatus of the present invention and a first embodiment of a data recording method applied to the first embodiment of the data recording apparatus.

FIG. 4 is a graph showing the relationship between the second direct current and the reproduction output in the first embodiment of the above-mentioned data recording method.

FIG. 5 is a diagram illustrating a second embodiment of the data recording method applied to the first embodiment of the data recording device.

FIG. 6 is a diagram for explaining the configuration of the second embodiment of the data recording apparatus of the present invention and the third embodiment of the data recording method applied to the second embodiment of the data recording apparatus.

FIG. 7 is a perspective view showing permanent magnets arranged on a magnetic disk in a first magnetizing step of a third embodiment of the data recording method.

FIG. 8 is a diagram showing a distribution of magnetic flux density around a permanent magnet used in a first magnetizing step of a second embodiment of the data recording device.

FIG. 9 is a diagram illustrating an example in which the third embodiment of the data recording method is applied to a normal drive device.

FIG. 10 is a graph showing a distribution of magnetic flux density around a permanent magnet used in a first magnetizing step of an application example of the third embodiment of the data recording method.

FIG. 11 is a diagram illustrating an operation of a modified example of the third embodiment of the data recording method.

FIG. 12 is a diagram showing a distribution of magnetic flux density around a permanent magnet used in a second magnetizing step of the modified example.

FIG. 13 is a diagram showing a distribution of magnetic flux density in the longitudinal direction of a single rod-shaped permanent magnet.

FIG. 14 is a diagram showing a distribution of magnetic flux density in a direction perpendicular to the longitudinal direction of a single rod-shaped permanent magnet.

FIG. 15 is a diagram showing a schematic configuration of a conventional data recording device.

[Explanation of reference numerals] 2 magnetic heads 21, 22, 23, 24, 25 permanent magnets

Claims (7)

[Claims] 1. A data recording apparatus for recording data on a disk-shaped recording medium having a concave portion and a convex portion corresponding to data formed thereon, and a magnetic layer applied along the formed concave portion and the convex portion. And a magnetic head that faces the convex portion and applies a magnetic field to the concave portion and the convex portion, and the magnetic head applies a magnetic field in one direction to the concave portion and the convex portion, and to the convex portion. A data recording device characterized by applying a reversal magnetic field in the opposite direction. 2. A data recording device for recording data on a disk-shaped recording medium having a concave portion and a convex portion corresponding to data formed thereon, and a magnetic layer deposited along the formed concave portion and the convex portion. And a magnet that faces the convex portion and applies a magnetic flux in one direction to the concave portion and the convex portion, and a magnetic field generation unit that applies a magnetic field to the convex portion in a direction opposite to the direction of the magnetic field. A data recording device comprising: 3. The data recording device according to claim 2, wherein the magnet applies a magnetic flux to the magnetic layers of a plurality of disk-shaped recording media at the same time. 4. A data recording method for recording data on a disk-shaped recording medium on which a concave portion and a convex portion corresponding to data are formed, and a magnetic layer is attached along the formed concave portion and the convex portion. A magnetic field that applies a DC recording current to a magnetic head facing the layer to generate a magnetic field in the magnetic layer to magnetize the magnetic layer in one direction; and the magnetic head in the first magnetizing step. And a reverse magnetic field generated by applying a current smaller than the direct current recording current to the magnetic head to the magnetic layer of the convex portion, and A second magnetization step of reversibly magnetizing the layer. 5. A data recording method for recording data on a disk-shaped recording medium having a concave portion and a convex portion corresponding to data formed thereon, and a magnetic layer applied along the formed concave portion and the convex portion. A magnetic field that applies a DC recording current to a magnetic head facing the layer to generate a magnetic field in the magnetic layer to magnetize the magnetic layer in one direction; and the magnetic head in the first magnetizing step. A reverse magnetization that gives a current in a direction opposite to the direct current applied to the magnetic layer is generated, and a magnetic layer of the convex portion is formed from a position farther than the position of the magnetic head with respect to the magnetic layer in the first magnetization step And a second magnetization step of reversely magnetizing the magnetic layer of the convex portion. 6. A data recording method for recording data on a disk-shaped recording medium having a concave portion and a convex portion corresponding to data formed, and a magnetic layer adhered along the formed concave portion and convex portion, comprising: The magnets are arranged so as to sandwich the disk-shaped recording medium, and magnetic poles different from each other are made to face each other and the centers of the facing surfaces are displaced from each other by a predetermined distance, and a magnetic flux generated between the two magnets is applied to the magnetic layer. By a first magnetization step of magnetizing the magnetic layer in one direction with a magnetic field generating means for generating a magnetic field for inversely magnetizing the magnetic layer magnetized in the first magnetization step. A second magnetization step of applying a reversal magnetic field to the layer to reverse magnetize the magnetic layer of the convex portion. 7. The data recording method according to claim 6, wherein the first magnetizing step is a step of magnetizing magnetic layers of a plurality of disk-shaped recording media at the same time.