JPH03200011A - Magnetic medium and its manufacture - Google Patents

Abstract

PURPOSE:To easily and surely magnetize a face to be magnetized at a fine pitch and to obtain a high output by intermittently forming many magnetized parts consisting of magnetic films on the face to be magnetized of a base material consisting of a non-magnetic body. CONSTITUTION:A magnetic film is formed on the upper surface of the base material 11 consisting of a cupper-made disk. Masking materials are formed on the upper peripheral edge of the magnetic film at a prescribed pitch and then the magnetic film on the base material 11 is etched by ion beam etching to remove the film. Then the masking material is removed by dipping it into a peeling solution to form many magnetized parts 12 consisting of magnetic films each of which has a plane rectangular shape on the upper peripheral edge part of the base material 11. Then magnetizing yokes 15, 16 are arranged on the upper and lower parts of the base material 11 to magnetize the base material 11.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a magnetic medium in which only the magnetized part is made of a magnetic film and the other parts are made of a non-magnetic material, and a method for manufacturing the same. It relates to something that can be magnetized accurately and instantaneously and that can also provide high output.

"Prior art" A magnetic encoder, etc. that is used to read information recorded on magnetic media with a certain regularity using a magnetic sensor, output the output of this magnetic sensor as information such as position information, and perform automatic control. Magnetic devices have been developed and are now in widespread use.

The shape of the magnetic media used in this type of magnetic device is
There are various shapes such as disk-shaped or drum-shaped, but all have one thing in common: either the entire magnetized surface is made of magnetic material, or the entire magnetized surface is made of a magnetic material layer. It is said that it forms a

Conventionally, when magnetizing a magnetic medium having the above configuration, two methods described below are known.

The first method, as shown in FIG. The magnetic yoke 3 is brought close to the magnetized surface 5 of the magnetic medium 4, and a magnetic field is applied to the magnetic medium 4 for magnetization. Through this magnetization process, the magnetized surface 5 has N poles and S poles spaced at intervals equal to the distance between the magnetic pole protrusions 2.
The poles are formed alternately in sequence.

As shown in FIG. 7, the second method is to bring the C-shaped magnetizing yoke 7 close to the magnetized surface 9 of the magnetic medium 8 and magnetize it in one place, and then move the magnetizing yoke 7 or the magnetic medium 8 is moved a predetermined distance to make the magnetizing yoke 7 face another part of the magnetic medium 8, magnetization is performed again here, and after magnetization, the magnetic yoke 7 or the magnetic medium or medium 8 is moved again to S and N poles are intermittently formed on the magnetic medium 8 by repeatedly performing the operation of magnetizing a portion.

"Problem to be Solved by the Invention" Incidentally, in order to improve the recording density of the magnetic medium 4.8, it is necessary to make the magnetization interval as small as possible.

However, the magnetizing yoke 3 used in the first method is
The structure has a large number of magnetic pole protrusions 2, which have a complicated shape, and if a problem arises in the dimensional accuracy when forming the magnetic pole protrusions 2.2, there is a risk that the magnetization interval may fluctuate. Furthermore, since the magnetization interval is limited by the machining accuracy of the magnetic pole protrusions 2, there is a problem that there is a limit to the improvement in the recording density of the magnetic media.

Further, in the second method, since the magnetized surface 9 is magnetized one point at a time, magnetization takes time and has a problem of poor efficiency.

In addition, in the magnetic media 4.8, the entire surfaces of the magnetized parts 5 and 9 are made of magnetic material, and the north and south poles must be alternately magnetized with a predetermined distance between them. Because lines of magnetic force emerge in loops from the N and S poles, which are placed apart from each other, to the surface of the magnetized surface 5.9, when obtaining output from a magnetic head, etc., the N and S poles are There is a possibility that an extra output may be obtained due to the loop-shaped lines of magnetic force existing between the two, and in order to eliminate the influence of this extra output, there is a problem in that it is necessary to reduce the gap of the magnetic head.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a magnetic medium that can be easily and reliably magnetized at a fine pitch and that can obtain high output because it can be magnetized with the same polarity, and a method for manufacturing the same.

"Means for solving the problem" In order to solve the problem, the invention stated in claim 1 has the following features:
A large number of magnetized parts made of a magnetic film are intermittently formed on the magnetized surface of a base material made of a non-magnetic material.

In order to solve the above problem, the invention described in claim 2 has the following features:
A magnetic film is formed on the entire magnetized surface of a base material made of a non-magnetic material, this magnetic film is partially covered with a mask material, and then the parts of the magnetic film not covered with the mask material are removed. A magnetized part made of a magnetic film is formed by selectively removing it by etching, and then magnetic poles are arranged to sandwich the magnetized part from the front side and the back side, and all of the magnetized parts are simultaneously covered. It is magnetized.

In order to solve the above problem, the invention described in claim 3 has the following features:
The magnetized surface of the base material made of a non-magnetic material is partially covered with a mask material, and a magnetic film is formed on the magnetized surface of the base material that is not covered with the mask material to form a magnetized part. Next, magnetic poles are arranged so as to sandwich the magnetized surface from the front side and the back side, and all of the magnetized parts are simultaneously magnetized.

"Effect" Each magnetized part is individually magnetized on the magnetized surface made of non-magnetic material, and each magnetized part is magnetized independently, so the same polarity is placed above the magnetized surface of the base material. This makes it possible to magnetize the material so that it faces. Therefore, the magnetic field of the magnetized part is present at a position farther away than in conventional magnetic media, which improves output and enables magnetic detection at a position further away from the magnetized part.

A large number of magnetized parts are formed at a distance from each other on the magnetized part of a non-magnetic base material, and a base material made of a non-magnetic material is provided between each magnetized part, so that the By arranging magnetic poles on both sides of the magnetic surface and applying a magnetic field, all the magnetized parts are magnetized simultaneously.

The present invention will be explained in more detail below.

FIG. 1 shows an example in which the present invention is applied to a magnetic medium for a rotary encoder. The magnetic medium 10 of this example has a top surface (adhered surface) of a disc-shaped base material II made of a non-magnetic material. Magnetic surface) At a constant pitch on the outer periphery of IIA @
A large number of thin magnetized portions I2 are formed.

The base material 11 is made of a non-magnetic metal material such as copper, aluminum, or stainless steel.

Note that the constituent material of the base material 11 may be any material other than metal material as long as it is strong enough to withstand the film forming process and etching process described later.

The magnetized portions I2 are made of magnetic films having a planar rectangular shape formed on the upper surface 11A of the base material 11, and are formed in large numbers at a constant pitch on the circumferential portion of the upper surface of the base material I+.

An example of a method for manufacturing the magnetic media 10 by forming the magnetized portion 12 on the base material 11 will be described below.

Once a disk-shaped base material 11 is prepared, a magnetic film is formed on the entire upper surface of the base material 11 by a thin film forming method such as a vacuum evaporation method, a sputtering method, or a plating method. Specifically, as the magnetic film, 5ffiCOs, 5llC
Films such as O+t, NdtFe14B, etc. can be used.

Once the magnetic film is formed, a mask material is formed on the upper surface of the magnetic film so as to cover a portion of the base material If corresponding to the formation position of the magnetized portion 12. Specifically, a mask material made of a positive resist (trade name: 0FPfl-5000, manufactured by Tokyo Ohka) can be used. Further, as a method for forming this mask material on the upper surface 11A of the base material 11, a spin cord method or the like can be used.

Once the mask material is formed on the upper surface 11A of the substrate 11, wet etching or plasma etching is performed by immersing the base material 11 on which the mask material is formed in an etching solution.
The portion of the magnetic film that is not covered by the mask material is removed using one of the dry etching techniques typified by sputter etching, ion beam etching, and the like.

After performing this etching, if the mask material on the base material 11 is removed by means such as immersing it in a stripping solution, the base material E
As shown in FIG. 3, magnetized portions 13 made of a magnetic film are formed at a constant pitch on the upper surface layer seam portion of 1. As shown in FIG. Note that, if necessary, the mask material may be left on the magnetic film as a protective layer.

Next, as shown in FIG. 3, the base material 11 is magnetized with its upper and lower sides sandwiched between plate-shaped magnetizing yokes 1516. For this magnetization, if the upper magnetizing yoke 15 is the N pole and the lower magnetizing yoke 16 is the S pole, as shown in FIG.
Each magnetized part I3... is independent on the base material 11 made of a non-magnetic material, so an S pole is formed on the upper side of each magnetized part 13, and an N pole is formed on the lower side. A magnetic portion 12 is formed.

By magnetizing as described above, all the magnetized parts 13 can be simultaneously magnetized and magnetized 1112 . . . can be formed. Therefore, the magnetized portions 12 can be formed much more easily and quickly than in the conventional method. Furthermore, the precision in forming the magnetized portion 12 depends on the precision in forming the mask material on the base material, and the precision in forming the mask material is difficult to achieve during microfabrication in the field of manufacturing semiconductor integrated circuits. As is commonly used, it can be formed with extremely high precision on the micron order.

In addition, when magnetized as described above, the upper side of the base material 11,
That is, it becomes possible to magnetize the tips of each magnetized portion I2 with the same polarity as shown in FIG. 4. Therefore, compared to conventional magnetic media in which the entire surface of the magnetized surface is made of a magnetic material, the magnetic field can be applied to a far position on the base material. Therefore, in the magnetic media IO having the above structure, compared to conventional magnetic media, a sufficiently high output can be obtained even when the magnetic head is placed at a distance from the top surface of the base material 11 to read information. It will be done.

Note that when manufacturing magnetic media, the method described below can also be performed.

A base material 11 equivalent to the above example is prepared, and this base material! The size is such that it can cover the entire top surface of l,
A mask material having minute through holes formed at a predetermined pitch on the peripheral edge is formed on the base material If.

The through holes in the peripheral edge of this mask material are formed so as to correspond to positions on the magnetized surface of the base material 11 where the magnetized portions are to be formed. To form this masking material, a preformed masking material may be attached onto the base material II, or a preliminary masking material may be formed on the substrate 11, and then a masking material may be formed on the entire surface. Thereafter, only the portion on which the preliminary mask material has been formed may be removed by etching or the like to obtain a mask material with through holes formed in the portion from which the preliminary mask material has been removed.

Next, look through the mask material to see the top surface of the mask material and the base material l! A magnetic film is formed on the upper surface by the above-mentioned film forming method such as vacuum evaporation. After forming the magnetic film, the mask material is applied to the base material 11.
remove from As the means for removing the mask material, the means explained in the previous example may be used.

By removing the mask material from the base material II, magnetized parts made of magnetized layers are formed on the base material II at a predetermined pitch.

Therefore, if the magnetic medium is then magnetized as shown in FIG. 3 using a magnetizing yoke in the same manner as in the previous example, a magnetic medium can be obtained and the same effect as in the previous example can be obtained.

“Example” A disc-shaped base material made of copper is used, and SmCo is coated on the top surface of this base material.
A magnetic film with a thickness of 50 μm was formed. Next, a rectangular mask material made of positive type resist was formed at a predetermined pitch on the periphery of the upper surface of this magnetic film, and then the magnetic film on the base material was etched and removed by ion beam etching. Subsequently, the mask material was removed by immersing it in 8111 liquid, and a large number of magnetized parts made of magnetic films having a planar rectangular shape were formed at a pitch of 50 μm on the periphery of the upper surface of the base material.

After this, as shown in FIGS. 3 and 4, magnetizing yokes were placed above and below the base material and magnetized.

Recorded information was read from the magnetic media obtained as described above using a magnetic head.

During reading, we measured the change in output when changing the gap between the magnetic head and the magnetic medium. The results are shown in FIG. 5 by circles.

Furthermore, by the conventional method explained based on FIG.
Comparison magnetic media was created by magnetizing a magnetic film made of CrCo one point at a time at the same pitch as the magnetic media described above, and the recorded information was read in the same way as the magnetic media described above to determine the change in output. was measured. The results are shown in FIG. 5 by the symbol Δ.

From the results shown in FIG. 5, it was found that the magnetic media manufactured according to the method of the present invention can provide higher output even if the gap is wider.

"Effects of the Invention" As explained above, the present invention has the following advantages:
Since a large number of magnetized parts made of a magnetic film are formed intermittently, when forming the magnetized parts, the magnetized parts are sandwiched between both sides of the base material with a magnetizing yoke and magnetized, so that they can be magnetized all at once on the base material. A large number of magnetized parts can be formed at the same time, which has the effect of making magnetic media easier to manufacture than in the past.

Moreover, since the magnetized parts are each formed independently on the non-magnetic base material, there is no need to alternately magnetize the N pole and the S pole adjacently. For this reason, it is possible to form a magnetized part by aligning the same magnetic poles toward the upper side of the base material, compared to conventional magnetic media in which magnetic poles are formed alternately.
It becomes possible to detect the magnetic field at a farther position on the substrate, and it becomes possible to obtain high output even if the gap between the successive head and the magnetic medium is increased.

On the other hand, a mask material is coated on the base material to form a magnetic film,
By removing the mask material, the magnetized portions of the magnetic film can be formed only at required positions, and the magnetized portions can also be formed all at once. In addition, the formation accuracy of the magnetized part is derived from the formation accuracy of the mask material, but since the mask material can be easily formed with sufficiently fine precision, the magnetized part can be formed with high precision at a fine pitch. A magnetized portion can be formed by forming a magnetized portion.

[Brief explanation of drawings]

FIG. 1 is a plan view of a magnetic medium according to an embodiment of the present invention, FIG. 2 is a side view of the magnetic medium, and FIG. 3 is a side view for explaining an example of a method of magnetizing the magnetic medium. Figure 4 is an enlarged view to explain an example of the same magnetization method, Figure 5 is a diagram showing the relationship between the output of the magnetic media and the gap obtained in the example, and Figure 6 is an example of the conventional magnetization method. FIG. 7 is an explanatory diagram showing another example of the conventional magnetization method. IO: Magnetic media, II: Base material, IIA: Top surface (
(Magnetized part), 12... Magnetized part, 13... Magnetized part,
15.16... Magnetizing yoke.

Claims (3)

[Claims] (1) A magnetic medium characterized in that a large number of magnetized parts made of a magnetic film are intermittently formed on a magnetized surface of a base material made of a non-magnetic material. (2) After forming a magnetic film on the entire magnetized surface of a base material made of a non-magnetic material and partially covering this magnetic film with a mask material, the magnetic material in the part not covered with the mask material The body film is selectively removed by etching to form a magnetized part made of a magnetic film, and then a magnetizing yoke is arranged so as to sandwich the magnetized surface from the front side and the back side. A method for manufacturing magnetic media characterized by magnetizing all parts at the same time. (3) The magnetized surface of the base material made of non-magnetic material is partially covered with a mask material, and a magnetic film is formed on the magnetized surface of the base material not covered with the mask material to form the magnetized part. 1. A method for manufacturing a magnetic media, which comprises forming a magnetized surface, and then arranging a magnetizing yoke so as to sandwich the magnetized surface from the front side and the back side to simultaneously magnetize all of the magnetized parts.