JPH06111309A - Vapor deposition device for magnetic recording medium - Google Patents

Abstract

PURPOSE:To continuously form two layers of vapor deposition type magnetic layers having different column structures on a nonmagnetic base material and to simultaneously form a back coating layer on the rear surface. CONSTITUTION:First and second guide bodies 4, 5 are provided above a can 3. The opposite spacing between a first route A of the nonmagnetic base material 8 heading toward the can 3 from the first guide body 4 and a second route B of the nonmagnetic base material 8 heading toward the second guide body 5 from the can 3 is so set as to be narrower on the guide body 4, 5 side than the can 3 side. An evaporating source 9 of a magnetic material is disposed into the space held by the first and second routes A, B. An evaporating source 15 for metal for forming the back coating layer is disposed below the can 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition apparatus used for manufacturing magnetic recording media.

[0002]

2. Description of the Related Art As a magnetic recording medium such as a magnetic tape, a vapor deposition type in which a magnetic material is deposited on a non-magnetic base material in a vacuum to form a magnetic layer is compared to a conventional coating type. Since the magnetic layer does not contain a binder, the density of the magnetic material can be increased, and it is attracting attention as being promising for high-density recording.

FIG. 3 shows a conventional vapor deposition apparatus used for manufacturing a vapor deposition type magnetic recording medium. The vacuum container 21 is evacuated by a vacuum pump 22. Inside the vacuum container 21, there is provided a cylindrical can 23 that rotates with an axis line in the horizontal direction, and a take-up roll 24 and a take-up roll 25 are provided above the can 23. Where the unwind roll
The non-magnetic base material 26 unwound from 24 moves along the lower peripheral surface of the can 23 and is wound up by the winding roll 25.

Below the can 23, a magnetic material evaporation source 27 is provided.
The crucible 28 is provided with a magnetic material 29 such as a Co—Ni alloy, and the magnetic material 29 is heated and evaporated by an electron beam emitted from an electron beam gun (not shown). Then, the vapor flow is regulated by the shield plate 30 toward the can 23, and the magnetic material is deposited on the non-magnetic base material 26 moving along the can 23.

In the case of the apparatus shown in FIG. 3, the oblique deposition shown in FIG.
A magnetic layer 31 having a column structure as shown in FIG. Further, when forming the magnetic layer, the oblique vapor deposition direction is changed and the vapor deposition is performed twice, so that the column structure (inclination direction) is different on the non-magnetic substrate 26 as shown in FIG.
It is known that when the magnetic layers 32 and 33 of the two layers are formed to have the same overall film thickness, the column does not become thicker, the characteristics in the high frequency range are improved, and the dependence of the magnetic recording / reproducing characteristics on the medium running direction can be extremely reduced. (Japanese Patent Laid-Open No. 63-63
-113928 gazette).

[0006]

However, when the magnetic layer is composed of two layers having different column structures, if the vapor deposition is simply performed twice, the cost is increased due to the increase of the man-hours, and the vapor deposition apparatus ( In particular, two evaporation sources are required and the apparatus becomes large. Therefore, JP-A-53-877
By utilizing the technique disclosed in Japanese Patent Publication No. 06 (FIG. 3), as shown in FIG. It was considered to carry out two-layer vapor deposition continuously at 27.

However, in this case, the central portion having the highest vapor density in the vapor flow from the evaporation source 27 is blocked by the shield plate 33, so that the vapor deposition efficiency is poor. Further, when manufacturing a magnetic recording medium, the back surface of the non-magnetic base material (the surface opposite to the magnetic layer) is provided with conductivity to prevent electrification, and surface stability (friction coefficient) is controlled to ensure running stability. To prevent warpage due to the balance with the magnetic layer on the surface side, a backcoat layer is coated with a coating of carbon dispersed in a binder, but this is a separate process from the magnetic layer formation. , Productivity was poor.

In view of the above-mentioned conventional problems, the present invention enables continuous vapor deposition of two magnetic layers with one evaporation source of a magnetic material and can be efficiently performed. An object of the present invention is to provide a vapor deposition apparatus for a magnetic recording medium that can be simultaneously formed by vapor deposition.

[0009]

Therefore, according to the present invention, a non-magnetic base material for a magnetic recording medium is provided in a vacuum container with its axis lined out in a substantially horizontal direction, and the peripheral surface on the lower side thereof is wound. Above the cylindrical can to be hung, a first guide body that guides the non-magnetic base material toward the can and a second guide body that guides the non-magnetic base material from the can are provided from the first guide body. While the facing distance between the first path of the non-magnetic base material toward the can and the second path of the non-magnetic base material from the can toward the second guide is narrower on the guide side than on the can side, An evaporation source of a magnetic material for forming a magnetic layer is arranged in a space sandwiched by the first and second paths, and an evaporation source of a metal for forming a back coat layer is arranged below the can, thereby forming a magnetic recording medium. Configure a vapor deposition device.

Further, it is preferable to provide an oxygen introducing pipe for introducing oxygen in the vicinity of the vapor deposition site of the metal for forming the back coat layer.

[0011]

In the above structure, one magnetic material evaporation source deposits the magnetic material on the non-magnetic base material on the first path and the non-magnetic base material on the second path. At this time, the first
Since the moving direction of the non-magnetic base material on the path is opposite to the moving direction of the non-magnetic base material on the second path, oblique deposition is performed in different directions, and two magnetic layers having different column structures are formed. Are continuously formed.

Here, if the distance between the first and second guide bodies is made sufficiently small, the escape of the magnetic material from the evaporation source can be minimized, and the vapor deposition efficiency is improved. Also,
By arranging the evaporation source of the metal for forming the back coat layer below the can, the metal is vapor-deposited on the back surface of the non-magnetic base material in the middle where the two magnetic layers are formed on the front surface of the non-magnetic base material. At the same time, a back coat layer is formed.

When an oxygen introducing pipe for introducing oxygen is provided in the vicinity of the metal deposition site for forming the back coat layer, the surface roughness of the back coat layer is roughened by the oxidation action, and the back coat layer is formed by simple vacuum deposition. It is possible to prevent the running stability from being deteriorated due to excessive smoothness. Further, the oxide film also improves the corrosion resistance.

[0014]

Embodiments of the present invention will be described below with reference to FIGS. With reference to FIG. 1, the vacuum container 1 is evacuated by a vacuum pump 2. Inside the vacuum container 1, there is provided a cylindrical can 3 that rotates with an axis line in the horizontal direction. In addition, cooling water circulates inside the can 3.

Above the can 3, first and second guide bodies 4 and 5 are provided. The first and second guide bodies 4 and 5 are guide rolls that can rotate together, and are arranged parallel to each other and parallel to the can 3. An unwinding roll 6 is provided beside the first guide body 4, and a take-up roll 7 is provided beside the second guide body 5.

Here, the first guide body 4 guides the non-magnetic base material 8 such as a PET (polyethylene terephthalate) film which is unwound from the unwinding roll 6 and can 3
The second guide body 5 guides the non-magnetic base material 8 from the can 3 to be wound around the winding roll 7. Also,
Opposing distance between the first path A of the non-magnetic base material 8 from the first guide body 4 to the can 3 and the second path B of the non-magnetic base material 8 from the can 3 to the second guide body 5. However, the guide body 4, 5 side (upper side) is narrower than the can 3 side (lower side),
The first and second guide bodies 4 and 5 are arranged close to each other. The space S is about 5 to 10 mm. The inclination angles θ of the first and second paths A and B are 20 to 45 °.

In a space above the can 3 and sandwiched by the first and second paths A and B, a Cr— crucible 10 made of MgO, a Co—Ni alloy, and Co—C are used as an evaporation source 9 of the magnetic material.
A magnetic material 11 such as an r alloy or a Co-Cr-Ta alloy is put in and provided, and the magnetic material 11 is heated and evaporated by an electron beam emitted from an electron beam gun (not shown). Note that the electron beam gun may be arranged anywhere as long as the electron beam is appropriately deflected and focused by a deflection coil, a focusing coil, or the like to irradiate the magnetic material 11. Reference numeral 12 is a shielding plate that prevents downward diffusion of the vapor flow.

Further, cooling plates 13 and 14 for cooling the non-magnetic base material 8 are provided along the first and second paths A and B on the side opposite to the side where the magnetic material evaporation source 9 is located (back side). It is arranged. With reference to FIG. 2, the cooling plates 13 and 14 will be described with reference to FIG. 2. The cooling water inlet 13a is provided on the lower side and the cooling water outlet 13b is provided on the upper side.
By this, the cooling water is made to flow around and the non-magnetic base material 8 at the vapor deposition site is cooled from the back surface side.

Below the can 3, as a metal evaporation source 15 for forming a back coat layer, a CrO crucible 16 made of MgO
A metal 17 such as 1, Zn, Sn, Ni, or Ag is put in and provided, and the metal 11 is heated and evaporated by an electron beam emitted from an electron beam gun (not shown). In addition, as the metal for forming the back coat layer, the price,
From the viewpoint of vapor deposition rate and stability after oxidation, Al is optimal.

A shielding plate 18 for restricting the vapor deposition range of the evaporation source 15 is arranged between the crucible 16 and the can 3. The tip of the oxygen introducing tube 19 led from the outside of the vacuum container 1 to the inside is arranged toward the deposition site of the evaporation source 15. The amount of oxygen introduced can be adjusted by a flow rate control valve (not shown).

Next, the operation will be described. After being unwound from the unwinding roll 6, the non-magnetic base material 8 is guided by the first guide body 4 toward the can 3, and is guided by the second guide body 5 from the can 3 to the unwinding roll 7. The first is
In the first route A from the guide body 4 to the can 3, the magnetic material from the evaporation source 9 is attached to the surface of the non-magnetic base material 8 to deposit the first layer, and the can 3 to the second layer. In the second route B toward the guide body 5, the magnetic material from the evaporation source 9 is attached again onto the vapor deposition surface of the first layer of the non-magnetic base material 8 to vapor deposit the second layer.

At this time, the nonmagnetic substrate 8 on the first path A
Is opposite to the moving direction of the non-magnetic substrate 8 on the second path B, so that the evaporation source 9 of a single magnetic material is used, but oblique vapor deposition is performed in different directions. Of two different magnetic layers (see FIG. 5) are continuously formed. The distance S between the first and second guide bodies 4 and 5 is 5
It can be made as small as -10 mm, and most of the vapor can be attached to the non-magnetic base material 8 without letting the vapor from the evaporation source 9 escape, resulting in good vapor deposition efficiency. And since the vapor deposition rate can be increased correspondingly, productivity is also improved.

Further, in the process of the non-magnetic base material 8 moving on the lower peripheral surface of the can 3 with its back surface facing outward, oxygen is introduced into the back surface of the non-magnetic base material 8 by the oxygen introducing pipe 19. While being received, the metal evaporated from the evaporation source 15 of the metal for forming the back coat layer adheres to form the back coat layer. Therefore, according to the present apparatus, the two magnetic layers on the front surface side of the non-magnetic base material and the back coat layer on the back surface side can be simultaneously formed, and the productivity is significantly improved.

In forming the back coat layer by vapor deposition,
The reason for introducing oxygen is as follows. If the back coat layer is formed by simple vacuum deposition, that is, if it is a metal, the surface becomes too smooth and running stability deteriorates.Therefore, oxygen is introduced during vapor deposition to control the friction coefficient of the back coat layer. Then, the surface is roughened by the oxidizing action. By introducing oxygen, not only the surface roughness can be controlled but also the corrosion resistance can be improved.

Here, it is desirable to set the amount of oxygen introduced so that the surface resistance (resistance value) of the back coat layer is 5 to 10 ⁵ Ω / sq. That is, the introduction of oxygen weakens the metal bond and lowers the conductivity. Therefore, the resistance value is determined and the amount of oxygen introduced is regulated. A resistance value of 5 to 10 ⁵ Ω / sq means that the resistance value is 5 Ω.
If it is lower than / sq, the amount of oxygen is small and the friction coefficient of the back coat layer becomes too high. Resistance value is 10 ⁵ Ω / sq
If it is higher, the coefficient of friction becomes too high, and the conductivity becomes too low, which may lead to the attachment of dust. The target should be approximately 10 ³ Ω / sq. The center line average roughness corresponds to Ra = 8 to 20 nm.

By the apparatus of this embodiment, as a non-magnetic substrate
Using a 9.8 μm PET film, Co-
A total of two layers of Ni alloy (80% -20%) was vapor deposited to form a magnetic layer of 1500Å, and a back coat layer was formed on the back surface by vapor deposition of Al of 1000Å. Regarding the amount of oxygen introduced, the purity is 99.998.
% Oxygen was introduced at 25 cc / min. Then, 20Å top coat of perfluoropolyether (for example, product name "Homblin" manufactured by Montedison Co., Ltd.) was applied as a protective layer on the magnetic layer. After that, slit it to a width of 8 mm, put it in an 8 mm videotape cassette, and set it to a single frequency of 1 MHz.
The signals of MHz are recorded, these are reproduced, and the output (dB) and C / N (dB) are compared with the commercially available Sony Corporation 8mm reference tape (assuming the tape is 0dB).
Was measured. Also, for testing the backcoat layer, dropout and backcoat surface resistance were measured. still,
For the measurement of dropout, a dropout counter was used, and a dropout of −16 dB output within 10 μs was defined as dropout.

As a comparative example, a general vapor deposition apparatus as shown in FIG. 3 was used to deposit a single layer of Co—Ni alloy (80% -20%) on a 9.8 μm PET film surface at 1500 Å. Then, a 20Å top coat of perfluoropolyether was applied as a protective layer thereon. After that, on the back surface, a back coat layer having a particle size of 20 nm and a particle size of 60 nm was 1:
0.5μ thickness of the paint prepared by dispersing the carbon mixed in 1 in the binder in which vinyl chloride and urethane are mixed in 1: 1.
It was applied so that it would be m. The other conditions were the same as those in the example, and the same measurement was performed.

The results are shown in Tables 1 and 2.

[0029]

[Table 1]

[0030]

[Table 2]

From the results shown in Table 1, particularly in the high range (7 MHz), both the output and the C / N became large and excellent characteristics were obtained, and two layers of magnetic layers were obtained in the one manufactured by the apparatus of this example. The effect of vapor deposition was recognized. Further, from the results of Table 2, the dropout in the device manufactured by the apparatus of this example is about 30% lower than that in the comparative example. It is considered that this is because the backcoat layer was not applied to prevent scratches and dust, and the backcoat layer did not contain a binder to improve conductivity, so that dust could be prevented from adhering.

In the above-mentioned embodiment, if a small amount of oxygen is introduced from the outside toward the non-magnetic substrate 8 during the vapor deposition in the first and second paths A and B, the magnetic property is increased by the oxidation. There is an advantage that the corrosion resistance of each layer of the layers is improved and the two magnetic layers can be clearly separated.

[0033]

As described above, according to the present invention, two magnetic layers having different column structures can be continuously formed at one time by a single evaporation source of a magnetic material, and the vapor deposition efficiency can be improved. And good productivity can be obtained. Further, the back coat layer can be formed on the back surface by vapor deposition at the same time when the two magnetic layers are formed, and the productivity of the magnetic recording medium is significantly improved.

When an oxygen introducing pipe for introducing oxygen is provided in the vicinity of the vapor deposition site of the metal for forming the back coat layer, the back coat layer is provided with an appropriate surface roughness by the oxidation action to improve running stability. It is possible to obtain the effect of ensuring the corrosion resistance and improving the corrosion resistance.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vapor deposition apparatus showing an embodiment of the present invention.

FIG. 2 is a schematic view of a cooling plate in the above embodiment.

FIG. 3 is a schematic diagram showing a conventional example of a vapor deposition device.

FIG. 4 is a structural diagram of a single-layer magnetic layer.

FIG. 5 is a structural diagram of a two-layer magnetic layer.

FIG. 6 is a schematic view showing a conventional example of a vapor deposition apparatus for obtaining a two-layer type magnetic layer.

[Explanation of symbols]

 1 vacuum container 2 vacuum pump 3 can 4 first guide body 5 second guide body 6 unwinding roll 7 winding roll 8 non-magnetic base material 9 evaporation source of magnetic material 10 crucible 11 magnetic material 12 shielding plate 13, 14 Cooling plate 15 Evaporation source of metal for forming backcoat layer 16 Crucible 17 Metal for forming backcoat layer 18 Shielding plate 19 Oxygen introducing pipe A First route B Second route

Claims (2)

[Claims] 1. A can above and above a cylindrical can which is provided in a vacuum container with an axis line in a substantially horizontal direction and around which a non-magnetic base material for a magnetic recording medium is wound. A first guide body that guides the non-magnetic base material that faces the first guide body and a second guide body that guides the non-magnetic base material from the can are connected to the first guide body of the non-magnetic base material that faces the can from the first guide body. The path and the second path of the non-magnetic base material from the can to the second guide body are arranged such that the facing distance between the path and the guide body side is narrower than the can side, while the space sandwiched by the first and second paths. A vapor deposition apparatus for a magnetic recording medium, wherein an evaporation source of a magnetic material for forming a magnetic layer is arranged in the above, and an evaporation source of a metal for forming a back coat layer is arranged below the can. 2. An apparatus for depositing a magnetic recording medium according to claim 1, wherein an oxygen introducing pipe for introducing oxygen is provided in the vicinity of a vapor deposition site of the metal for forming the back coat layer.