JPH06150310A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the process for production of the magnetic recording medium capable of improving productivity while assuring good durability at the time of forming protective films. CONSTITUTION:After magnetic metallic thin films are formed on a continuous substrate 22, the protective films are formed by a plasma CVD method on these magnetic metallic thin films. This continuous substrate 22 is made to travel several times between a pair of electrodes 25a and 25b at this time. The continuous substrate 22 is otherwise spirally wound around the peripheral surface of a roll past between a pair of these electrodes 25a and 25b and is made to travel in this state. A pair of the electrodes are adequately parallel flat plate electrodes connected to a high-frequency power source. These parallel flat plate electrodes and the above-mentioned continuous substrate 22 may be disposed in parallel or may be disposed approximately perpendicularly to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium in which a protective film is formed on a metal magnetic thin film formed as a magnetic layer on a non-magnetic support.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, a powder magnetic material such as an oxide magnetic powder or an alloy magnetic powder on a non-magnetic support is used as a vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, A so-called coating type magnetic recording medium is widely used in which a magnetic coating material is formed by coating a magnetic coating material dispersed in an organic binder such as a polyurethane resin and drying.

On the other hand, with the increasing demand for high-density magnetic recording, Co--Ni alloys, Co--Cr alloys, C
A metal magnetic material such as o--O is coated with a polyester film or polyamide by plating or a vacuum thin film forming means (vacuum deposition method, sputtering method, ion plating method, etc.).
A so-called metal magnetic thin film type magnetic recording medium, which is directly deposited on a non-magnetic support such as a polyimide film, has been proposed and put into practical use.

This metal magnetic thin film type magnetic recording medium is excellent not only in coercive force and squareness ratio but also in electromagnetic conversion characteristics at short wavelengths, and in addition, the magnetic layer can be extremely thinned for recording demagnetization and reproduction. There are various advantages such as a significantly small thickness loss at the time and the fact that it is not necessary to mix a binder, which is a non-magnetic material, in the magnetic layer, so that the packing density of the magnetic material can be increased.

Further, in order to improve the electromagnetic conversion characteristics of this type of magnetic recording medium and obtain a larger output, the magnetic layer is obliquely formed when forming the magnetic layer of the magnetic recording medium. The so-called oblique vapor deposition method, in which vapor deposition is performed on a substrate, is predominant.

In the meantime, in the metal magnetic thin film type magnetic recording medium, the track density and the recording density have been increased along with the high density magnetic recording as described above. Since the spacing loss increases as the recording density is increased, the surface of the medium tends to be smoothed in order to prevent the adverse effect. However, if the surface of the medium is too smooth, the magnetic head and the medium will be attracted,
Friction force increases. For this reason, the shearing force generated in the medium becomes large, and the magnetic recording medium may be damaged significantly.

Under these circumstances, a method of forming a protective film on the surface of the magnetic layer has been studied for the purpose of improving the durability of the medium. In particular, good results have been obtained by using a carbon film having excellent wear resistance as a protective film. This carbon protective film can be formed by, for example, a sputtering method or a CVD method.

[0008]

The method of forming the above carbon protective film by the sputtering method is to accelerate an inert gas such as Ar gas by using an electric field or a magnetic field, and repel the target atoms by its kinetic energy. , A physical process of forming a film by depositing the ejected atoms on a substrate. However, in this process, it is necessary to dispose the substrate opposite to the target, and the structure of the film forming apparatus is limited.

Further, although the above-mentioned sputtering method is widely adopted because it can form many kinds of films, it has a drawback that the film forming rate is very slow and the productivity is poor.

On the other hand, the above-mentioned CVD method is a chemical process in which the energy of plasma generated by using an electric field or a magnetic field is used to cause a chemical reaction in a gas as a raw material to form a film. Among them, in the parallel plate plasma CVD method, when the substrate is introduced between the pair of electrodes, usually,
The substrate is mounted on one electrode. Conventionally, in the parallel plate plasma CVD method, plasma is only used in the direction parallel to the electrode surface as a method of attaching the substrate, and the plasma in the depth direction between electrodes (perpendicular to the electrode surface) is used. Is not used. Therefore, it cannot be said that the plasma generated between the electrodes is used efficiently, and improvement thereof is desired.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and provides a method of manufacturing a magnetic recording medium capable of realizing excellent productivity in forming a protective film. With the goal.

[0012]

A method of manufacturing a magnetic recording medium according to the present invention is proposed to achieve the above-mentioned object. That is, the first invention of the present application is, in a method of manufacturing a magnetic recording medium in which a metal magnetic thin film and a protective film are sequentially formed on a continuous substrate, when the protective film is formed, the continuous substrate causes a gap between a pair of electrodes. It is characterized by being run multiple times.

A second invention of the present application is a method of manufacturing a magnetic recording medium in which a metal magnetic thin film and a protective film are sequentially formed on a continuous substrate, and when the protective film is formed, the continuous substrate is a pair. It is characterized in that the roll is wound around the peripheral surface of the roll passing through between the electrodes so as to run.

The method of manufacturing a magnetic recording medium of the present invention comprises forming a metal magnetic thin film as a magnetic layer on a continuous substrate and then forming a protective film on the surface of the magnetic layer. The plasma CVD method is used as. In the plasma CVD method, the continuous substrate is caused to run a plurality of times between a pair of electrodes, or is wound around a circumferential surface of a roll passing between the pair of electrodes in a spiral shape and made to run. As a result, the substrate is continuously introduced between the pair of electrodes, the productivity is improved, and the use efficiency of the plasma generated between the electrodes can be increased.

As the pair of electrodes, a parallel plate electrode connected to a high frequency power source can be used. At this time, the parallel plate electrode and the continuous substrate may be arranged in parallel or substantially vertically. In any case, the substrate is continuously introduced between the pair of electrodes, and the plasma in the depth direction generated between the electrodes is used. Therefore, for example, a discharge coil connected to a high frequency power source may be used as the electrode. In this case, the discharge coil is wound around the cylindrical plasma generation chamber, and the rotating roll is arranged on the central axis of the cylindrical plasma generation chamber. Then, the continuous substrate is spirally wound around the peripheral surface of the rotating roll and allowed to run.

The protective film material may be carbon, SiO ₂ , ZrO ₂ or the like, but is not particularly limited. These may be a single layer film, a multilayer film or a composite film. In the magnetic recording medium manufactured according to the present invention, as the material forming the metal magnetic thin film as the magnetic layer, any material can be used as long as it is a ferromagnetic metal material normally used in this type of magnetic recording medium. good.

For example, ferromagnetic metals such as Fe, Co and Ni, Fe--Co, Co--Ni and Fe--Co--N.
i, Fe-Cu, Co-Cu, Co-Au, Co-P
t, Mn-Bi, Mn-Al, Fe-Cr, Co-C
r, Ni-Cr, Fe-Co-Cr, Co-Ni-C
Ferromagnetic alloys such as r and Fe-Co-Ni-Cr can be mentioned. These may be a single layer film or a multilayer film. Further, an underlayer or an intermediate layer may be provided between the substrate and the metal magnetic thin film, or in the case of a multi-layer film, in order to improve the adhesive force between the layers and control the coercive force. Further, for example, the vicinity of the surface of the magnetic layer may be an oxide for improving the corrosion resistance.

As a method of forming the metal magnetic thin film, a vacuum vapor deposition method of heating and evaporating a ferromagnetic metal material under vacuum to deposit it on a non-magnetic support, or an evaporation of a ferromagnetic metal material in a discharge is performed. So-called PVD techniques such as an ion plating method and a sputtering method in which an atom on the target surface is knocked out by Ar ions generated by glow discharge in a sputtering atmosphere containing Ar gas as a main component can be used.

Of course, the structure of this magnetic recording medium is not limited to the above-mentioned structure, but may be changed without departing from the scope of the present invention, for example, a back coat layer may be formed or a base may be formed if necessary. There is no problem in forming an undercoat layer on the film surface or forming various functional layers such as a lubricant layer and a rust preventive agent layer. In this case, as the material contained in the non-magnetic pigment, the resin binder, or the lubricant layer or the rust preventive layer contained in the back coat layer, any conventionally known material can be used.

A non-magnetic support made of a non-magnetic material can be used as the continuous substrate, and any conventionally known substrate material for this type of magnetic recording medium can be used.

[0021]

When the protective film is formed on the metallic magnetic thin film formed as the magnetic layer on the continuous substrate, the plasma CVD method is adopted as the method for forming the protective film, so that a relatively high film forming rate is secured. It Further, in the plasma CVD method, the continuous substrate is caused to travel a plurality of times between a pair of electrodes, or is wound around a circumferential surface of a roll passing between the pair of electrodes in a spiral shape so that the continuous substrate travels between the pair of electrodes. The substrate is continuously introduced into the substrate, the productivity is improved, and the plasma generated in the depth direction between the electrodes is used.

[0022]

EXAMPLES Specific examples to which the present invention is applied will be described in detail below with reference to the drawings and experimental results. Example 1 In this example, a metal magnetic thin film was formed by vapor deposition on a base film, and then plasma CVD was performed while the base film was run between a pair of electrodes a plurality of times to form a protective film on the metal magnetic thin film. This is an example of forming a carbon film.

First, the structure of the vacuum vapor deposition apparatus used in this embodiment will be described. As shown in FIG. 1, in this vacuum vapor deposition apparatus, a counterclockwise rotation is made in a vacuum chamber 1 which is evacuated from the exhaust ports 15 and 15 provided at the head and the bottom to make the inside a vacuum state. A feed roll 3 that rotates at a constant speed in the direction and a winding roll 4 that rotates at a constant speed in the clockwise direction in the drawing are provided. A tape-shaped base film from the feed roll 3 toward the winding roll 4. 2 are run sequentially.

A cooling can 5 having a diameter larger than that of each of the rolls 3 and 4 is disposed in the middle of the traveling of the base film 2 from the feed roll 3 to the winding roll 4 side. The cooling can 5 is provided so as to draw the base film 2 downward in the figure, and is configured to rotate at a constant speed in the clockwise direction in the figure. In addition, a cooling device (not shown) is provided inside the cooling can 5 so as to suppress deformation of the base film 2 due to temperature rise.

The feed roll 3 and the take-up roll 4 are as described above.
The cooling can 5 and the cooling can 5 each have a cylindrical shape having a length substantially the same as the width of the base film 2.

Therefore, the base film 2 is sequentially fed from the feed roll 3, moved and run along the peripheral surface of the cooling can 5, and further wound on the winding roll 4 in sequence. ing. The rolls 3 and 4 are provided between the feed roll 3 and the cooling can 5 and between the cooling can 5 and the take-up roll 4.
Guide rolls 6 and 7 each having a smaller diameter are provided, and the feed roll 3 to the cooling can 5 and the cooling can 5
To a predetermined tension is applied to the base film 2 which runs over the take-up roll 4, so that the base film 2 runs smoothly.

In the vacuum chamber 1, a crucible 8 is arranged below the cooling can 5, and the crucible 8 is filled with a ferromagnetic metal material 9. The crucible 8 has a width substantially the same as the width of the cooling can 5.

On the other hand, an electron gun 10 for heating and evaporating the ferromagnetic metal material 9 filled in the crucible 8 is attached to the side wall of the vacuum chamber 1. This electron gun 10
Is arranged at a position where the ferromagnetic metal material 9 in the crucible 8 is irradiated with the electron beam X emitted from the electron gun 10. The ferromagnetic metal material 9 heated and evaporated by the electron gun 10 is cooled by the cooling can 5.
Is vapor-deposited on the base film 2 which runs at a constant speed on the peripheral surface of
A metal magnetic thin film, which is a magnetic layer, is formed.

A shutter 13 is provided between the cooling can 5 and the crucible 6 and near the cooling can 5.
Is provided. This shutter 13 has the cooling can 5 described above.
It is formed so as to cover a predetermined region of the base film 2 which runs at a constant speed along the peripheral surface of the base film 2, and controls the incident direction of the ferromagnetic metal material 9 to the surface of the base film 2. That is, in the evaporated ferromagnetic metal material 9, the minimum incident angle θ ₁ with respect to the surface of the base film 2 is regulated by the end of the shutter 13 on the feed roll 3 side, and a predetermined angle range θ _{2 to} θ. ₁ is obliquely evaporated.

Further, during such vapor deposition, oxygen gas is supplied to the vicinity of the surface of the base film 2 through an oxygen gas inlet 14 provided through the side wall of the vacuum chamber 1 and obtained. The magnetic properties, durability and weather resistance of the metal magnetic thin film have been improved.

In this vacuum deposition, the degree of vacuum in the vacuum chamber 1 is maintained at, for example, 1 × 10 ^-4 Torr, and the oxygen gas is introduced into the vacuum chamber 1 through the oxygen gas inlet 14 at, for example, 250 cc / min. Introduced in proportion. In this case, the incident angle of the ferromagnetic metal material 9 with respect to the base film 2 is in the range of 45 to 90 °. Further, the metal magnetic thin film serving as the magnetic layer is formed by vapor deposition in the cooling can 5 to have a thickness of 2000 liters, for example. The composition of the ingot used as the ferromagnetic metal material 9 is, for example, Co ₈₀ Ni ₂₀ (numerical values represent% by weight).

Next, the structure of the parallel plate type plasma CVD apparatus used in this embodiment will be described. As shown in FIG. 2, in this plasma CVD apparatus,
A feed roll 23a and a take-up roll 23b, which are rotated at a constant speed in the counterclockwise direction in the figure, are placed in a vacuum chamber 21 which has been evacuated from an exhaust port 29 provided in the side wall and has a vacuum inside.
And the tape-shaped base film 22 on which the metal magnetic thin film is formed by the vacuum evaporation method as described above is sequentially run from the feed roll 23a to the winding roll 23b. There is.

An intermediate roll 24, which rotates at a constant speed in the clockwise direction in the figure, is arranged in the middle of the base film 22 running from the feed roll 23a to the take-up roll 23b. The intermediate roll 24 is provided so as to pull out the base film 22 laterally in the drawing, and the base film 22 that has passed through the intermediate roll 24 reverses the traveling direction and travels back. .

The feed roll 23a, the take-up roll 23b and the intermediate roll 24 each have a cylindrical shape having a length substantially the same as the width of the base film 22.

Therefore, the base film 22 is sequentially fed from the feed roll 23a, and the vacuum chamber 21
Around the central portion of the inside of the drawing, it travels and travels in one lateral direction in the drawing, passes through the peripheral surface of the intermediate roll 24, runs back, and is further wound by the winding roll 23b in sequence. Has been done. In addition, the feed roll 23
a and the intermediate roll 24, and the intermediate roll 24
Between the feed roll 23a and the take-up roll 23b, the guide rolls 28a, 2 having a smaller diameter than the feed roll 23a and the take-up roll 23b and the same diameter as the intermediate roll 24.
8b are provided respectively, and a predetermined tension is applied to the base film 22 that runs from the feed roll 23a to the intermediate roll 24 and from the intermediate roll 24 to the winding roll 23b, so that the base film 22 smoothly moves. It is designed to run.

On the other hand, in the vacuum chamber 21, a pair of parallel plate electrodes 25a, 25b are sandwiched between the guide rolls 28a, 28b and the intermediate roll 24 so as to sandwich the base film 22 therebetween in the vertical direction in the figure. It is arranged to face each other.
Of these, one electrode 25a is grounded and the other electrode 2
5b is connected to a sufficiently grounded high frequency power source 27, and by applying a predetermined voltage to the electrode 25b by the high frequency power source 27, plasma is generated between the electrodes 25a and 25b. This electrode 2
5a and 25b are the base films 22 that travel back and forth between the guide rolls 28a and 28b and the intermediate roll 24.
Is arranged in parallel with.

Therefore, the base film 22 is designed to run twice between the electrodes 25a and 25b, and a protective film is formed while running back and forth between the guide rolls 28a and 28b and the intermediate roll 24. It is designed to be done. As described above, by configuring the base film 22 to pass between the electrodes 25a and 25b a plurality of times, the plasma in the depth direction generated between the electrodes 25a and 25b can be utilized, and the use of plasma The efficiency is improved.

When performing such plasma CVD,
A raw material gas is supplied to the vicinity of the surface of the base film 22 that passes through the peripheral surface of the intermediate roll 24 through a gas introduction port 26 that penetrates through the side wall of the vacuum chamber 21, and a predetermined atmosphere is created. Is being adjusted.

Then, using the vacuum vapor deposition apparatus and the plasma CVD apparatus having the above-mentioned constitutions respectively, the Co—Ni alloy is obliquely vapor-deposited in the oxygen gas atmosphere on the undercoated base film to obtain the film thickness. After depositing a metal magnetic thin film of 0.2 μm as a magnetic layer by vapor deposition, carbon was deposited on this metal magnetic thin film to form a protective film having a thickness of 15 nm. Further, a back coat and a top coat were applied to this and cut into a predetermined tape width to obtain a sample tape. In this example, in order to improve the electromagnetic conversion characteristics deteriorated by the formation of the protective film (to reduce the spacing loss), the drying conditions at the time of undercoating were appropriately adjusted, and the surface properties of the undercoated base film were adjusted. Controlled. The production conditions for this sample tape are as shown below.

<Production conditions of sample tape> Base film material: polyethylene terephthalate Base film thickness: 10 μm Base film width: 150 mm Undercoat: Water-soluble latex containing acrylic ester as a main component (surface protrusion density of about 1000)
10,000 pieces / mm ² ) Backcoat: Applying a mixture of carbon and urethane binder to a thickness of 0.6 μm Topcoat: Applying perfluoropolyether Slit width: 8 mm Protective film formation method: Parallel plate plasma CVD
Method Gas used for forming protective film: ethylene Vacuum degree for forming protective film: 7 to 9 Pa

Example 2 In this example, a metallic magnetic thin film was formed on a base film by vapor deposition in the same manner as in Example 1 described above, and then a pair of the base films were formed by using a parallel plate type plasma CVD apparatus shown in FIG. In this example, the carbon film is formed as a protective film on the metal magnetic thin film by performing plasma CVD while the electrode is reciprocated twice (four times in total).

First, the plasma CVD used in this embodiment.
The configuration of the device will be described. In addition, this plasma CV
The device D has the same basic structure as the plasma CVD device used in the first embodiment, and the same components are designated by the same reference numerals and the description thereof is omitted. That is,
In this plasma CVD apparatus, the feed roll 23a
The intermediate rolls 24a and 24c, which rotate at a constant speed in the clockwise direction in the figure, and the intermediate roll 24b, which rotates at a constant speed in the counterclockwise direction in the figure, are provided in the middle part where the base film 22 runs from the take-up roll 23b side. It is arranged.

The intermediate rolls 24a and 24c are provided so as to pull out the base film 22 to the right side in the figure, and the intermediate roll 24b is provided so as to be pulled out to the left side in the figure, and these intermediate rolls 24a and 24b are provided. , 2
The base film 22 that has passed 4c is configured so as to reverse the traveling direction and travel back. In addition,
Each of the intermediate rolls 24a, 24b, and 24c has a cylindrical shape having a length substantially the same as the width of the base film 22 like the feed roll 23a and the winding roll 23b.

Therefore, the base film 22 is sequentially fed from the feed roll 23a, and the vacuum chamber 21
After traveling around a substantially central portion in one of the lateral directions in the figure, the vehicle passes the peripheral surface of the intermediate roll 24a and turns back, and then passes through the peripheral surface of the intermediate roll 24b and turns back again. The electrodes 25a, 25
After reciprocating twice between b, it is sequentially wound around the winding roll 23b.

In this embodiment, three intermediate rolls 2 are used.
4a, 24b, 24c is configured to allow the base film 22 to travel between the electrodes 25a, 25b four times, but the invention is not limited to this, and the base film may be formed between the pair of electrodes by a method such as increasing the number of intermediate rolls. You may make it run many times.

Therefore, a sample tape was obtained under the same manufacturing conditions as in Example 1 using the same vacuum vapor deposition apparatus as in Example 1 and the plasma CVD apparatus having the above-described structure.

Example 3 In this example, a metal magnetic thin film was formed on a base film by vapor deposition in the same manner as in Example 1, and then the above-mentioned base film was formed by using a parallel plate type plasma CVD apparatus shown in FIG. Plasma CVD is performed while traveling twice between a pair of electrodes arranged in a direction in which the electric field generation direction is orthogonal to the traveling direction of the base film, and a carbon film is formed as a protective film on the metal magnetic thin film. It is an example.

First, the plasma CVD used in this embodiment.
The configuration of the device will be described. In addition, this plasma CV
The device D has the same basic structure as the plasma CVD device used in the first embodiment, and the same components are designated by the same reference numerals and the description thereof is omitted.

That is, in this plasma CVD apparatus, the guide rolls 28a, 2 are provided in the vacuum chamber 21.
8b and the intermediate roll 24, the pair of parallel plate electrodes 30a, 30 sandwiching the base film 22 that reciprocates.
b is arranged to face each other. These electrodes 30a and 30b are connected to a high frequency power source 27, and a plasma is generated by applying a predetermined voltage between the electrodes 30a and 30b by the high frequency power source 27.
The electrodes 30a, 30b are connected to the guide rolls 28a, 28
It is arranged in parallel with the width direction of the base film 22 that travels back and forth between b and the intermediate roll 24, that is, in the direction in which the electric field generation direction is orthogonal to the running direction of the base film 22.

Therefore, a sample tape was obtained under the same manufacturing conditions as in Example 1 using the same vacuum vapor deposition apparatus as in Example 1 and the plasma CVD apparatus having the above-described structure.

Example 4 In this example, a metal magnetic thin film was formed on a base film by vapor deposition in the same manner as in Example 1, and then the base film was spirally formed on the peripheral surface of a roll which passed between a pair of electrodes. In this example, the carbon film is formed as a protective film on the metal magnetic thin film by performing plasma CVD while winding and running.

First, the structure of the parallel plate type plasma CVD apparatus used in this embodiment will be described. As shown in FIG. 5, in this plasma CVD apparatus, the inside of the vacuum chamber 91 is evacuated from the exhaust port 99 provided in the side wall and is kept in a vacuum state. The feed roll 93a and the take-up roll 93b are arranged on a diagonal line, and the tape-like tape is formed from the feed roll 93a toward the take-up roll 93b on which the metal magnetic thin film is formed by the vacuum deposition method as described above. The base film 92 is designed to run sequentially.

A rotating roll 94, which rotates at a constant speed in the clockwise direction in the figure, is disposed in the middle of the base film 92 running from the feed roll 93a to the take-up roll 93b. The rotating roll 94 is provided so as to pull out the base film 92 to a substantially central portion in the drawing,
The base film 92 is spirally wound around the rotating roll 94 so that the base film 92 does not overlap with the base film 92, and the base film 92 runs.

Therefore, the base film 92 is sequentially fed out from the feed roll 93a, supported by the peripheral surface of the rotary roll 94, moved and run, and further taken up by the take-up roll 93b. Has been done. Here, the diameter of the rotating roll 94 was 10 cm. On the other hand, in the vacuum chamber 91, a pair of parallel plate electrodes 95a and 95b are arranged so as to face each other in the vertical direction in the figure with a rotating roll 94 around which the base film 92 is spirally wound between them. Of these, one electrode 95a is grounded and the other electrode 95b is connected to a sufficiently grounded high frequency power source 97.
By applying a predetermined voltage to the electrode 95b by means of 7, plasma is generated between the electrodes 95a and 95b. The electrodes 95a and 95b are arranged so that the plasma generation direction between the electrodes 95a and 95b and the axial direction of the rotating roll 94 are orthogonal to each other.

Therefore, the base film 92 is adapted to run while being supported by the peripheral surface of the rotating roll 94 passing between the electrodes 95a and 95b, and while passing through the peripheral surface of the rotating roll 94. A protective film is formed. In this way, by adopting a configuration in which the base film 92 moves along the peripheral surface of the rotating roll 94, the same effect as that of the first embodiment can be obtained.

When performing such plasma CVD,
A raw material gas is supplied to the vicinity of the surface of the base film 92 passing through the peripheral surface of the rotating roll 94 through a gas inlet 96 provided through the side wall of the vacuum chamber 91, and a predetermined atmosphere is created. Is being adjusted.

Therefore, a sample tape was obtained under the same manufacturing conditions as in Example 1 using the same vacuum vapor deposition apparatus as in Example 1 and the plasma CVD apparatus having the above configuration.

Example 5 In this example, a metallic magnetic thin film was formed by vapor deposition on a base film in the same manner as in Example 1, and then a cylindrical plasma generation in which a discharge coil connected to the high frequency power source was wound. A rotating roll is arranged on the central axis of the chamber, plasma CVD is performed while the base film is spirally wound around the rotating roll and running, and a carbon film is formed on the metal magnetic thin film as a protective film. This is an example of film formation.

First, the structure of the parallel plate type plasma CVD apparatus used in this embodiment will be described. As shown in FIG. 6, in this plasma CVD apparatus, a constant speed rotation is performed in a clockwise direction in the drawing in a vacuum chamber 101 which has been evacuated from an exhaust port 109 provided in a side wall portion and has a vacuum inside. Feed roll 103a and take-up roll 103b
And are arranged on a diagonal line, and these feed rolls 10
The tape-shaped base film 102 on which the metal magnetic thin film is formed by the vacuum evaporation method as described above is sequentially run from 3a toward the winding roll 103b.

A rotating roll 104, which rotates at a constant speed in the clockwise direction in the figure, is disposed in the middle of the base film 102 running from the feed roll 103a to the take-up roll 103b. The rotary roll 104 has the same structure as the rotary roll 94 of the plasma CVD apparatus used in the above-described fourth embodiment, and a detailed description thereof will be omitted here.

Here, the diameter of the rotating roll 104 was 10 cm.

On the other hand, in the vacuum chamber 101, a cylindrical plasma generating chamber 100 is arranged around the rotating roll 104 and on the same central axis as the rotating roll 104, around which the discharge coil 110 is wound. It That is, the rotating roll 104 passes through the center of the plasma generation chamber 100.
Will be arranged. The discharge coil 110
Is connected to a high frequency power source 107, and by applying a predetermined voltage to the discharge coil 110 by the high frequency power source 107, plasma is generated in the plasma generation chamber 100.

Therefore, the base film 102 is adapted to run while being supported by the peripheral surface of the rotating roll 104 passing through the central portion of the plasma generating chamber 100, while passing through the plasma generating chamber 100. A protective film is formed on. In this way, by adopting a configuration in which the base film 102 moves along the peripheral surface of the rotating roll 104, the same effect as that of the first embodiment can be obtained.

When performing such plasma CVD,
The raw material gas is supplied to the vicinity of the surface of the base film 102 passing through the peripheral surface of the rotating roll 104 through a gas inlet 106 provided through the side wall of the vacuum chamber 101, and a predetermined atmosphere is created. Is being adjusted.

Therefore, a sample tape was obtained under the same manufacturing conditions as in Example 1 using the same vacuum vapor deposition apparatus as in Example 1 and the plasma CVD apparatus having the above configuration.

Comparative Example 1 A sample tape in which a metal magnetic thin film was vapor-deposited and formed on a base film under the same production conditions as in Example 1 using the same vacuum vapor deposition apparatus as in Example 1 above, and a protective film was not formed. Was produced.

Comparative Example 2 Using the same vacuum vapor deposition apparatus as in Example 1 above, a metal magnetic thin film was formed by vapor deposition on a base film, and then carbon was sputtered on the metal magnetic thin film using the sputtering apparatus shown in FIG. A sample tape was produced under the same production conditions as in Example 1 except that the protective film was formed.

The structure of the sputtering apparatus is as follows. As shown in FIG. 7, in the above-described sputtering apparatus, the feed roll 113a and the take-up roll 113b are arranged in a vacuum chamber 111 which is evacuated from an exhaust port 119 provided in a side wall portion and has a vacuum inside. Has been set up,
The base film 112 is sequentially run from the feed roll 113a toward the winding roll 113b.

The guide rolls 118a, 1b are provided between the feed roll 113a and the winding roll 113b.
18b are provided respectively, and a predetermined tension is applied to the base film 112 running from the feeding roll 113a to the winding roll 113b so that the base film 112 runs smoothly.

On the other hand, in the vacuum chamber 111, a target electrode 115 to which a high frequency power source 117 is connected is disposed below the base film 112, and moves from the feed roll 113a toward the take-up roll 113b. The running base film 112 is configured to be sputtered. In addition, the gas introduction port 1 provided by penetrating the side wall of the vacuum chamber 111.
A sputter gas is supplied between the base film 112 and the target electrode 115 via 16.

The conditions for such sputtering are shown below. <Sputtering conditions> Method: DC magnetron sputtering target material: Carbon input power: 5 W / cm ² Working gas: Ar gas Vacuum degree during sputtering: 2 Pa Protective film thickness: 15 nm

Comparative Example 3 Using the same vacuum vapor deposition apparatus as in Example 1 above, a metal magnetic thin film was formed by vapor deposition on a base film, and then the conventional parallel plate type plasma CVD apparatus shown in FIG. 8 was formed on this metal magnetic thin film. Was used to form a carbon protective film under the same production conditions as in Example 1 above to obtain a sample tape.

The structure of the plasma CVD apparatus is as follows. As shown in FIG. 8, in the plasma CVD apparatus, the inside of the vacuum chamber 121, which is evacuated from the exhaust port 129 provided in the side wall portion to be in a vacuum state,
A feed roll 123a and a take-up roll 123b are provided, and the base film 122 is sequentially run in one direction from the feed roll 123a toward the take-up roll 123b.

The guide rolls 128a, 1b are provided between the feed roll 123a and the take-up roll 123b.
28b are provided respectively, and a predetermined tension is applied to the base film 122 running from the feed roll 123a to the winding roll 123b so that the base film 122 runs smoothly.

On the other hand, in the vacuum chamber 121, a pair of parallel plate electrodes 125 with the base film 122 sandwiched therebetween.
a and 125b are provided. Of these, one electrode 12
5a is grounded so that the base film 122 passes near the surface of the electrode 125a. The other electrode 125b is connected to a sufficiently grounded high frequency power source 127, and when a predetermined voltage is applied to the high frequency power source 127, plasma is generated between the electrode 125a and the electrode 125a, and plasma CVD is performed. To be done.

Also, the electrode 125 is inserted through a gas inlet 126 provided through the side wall of the vacuum chamber 121.
A raw material gas is supplied between a and 125b.

With respect to the sample tapes produced in Examples 1 to 5 and Comparative Examples 1 to 3 as described above,
Still durability and productivity were examined. The results are shown in Table 1 below. Still durability is 8mm VTR (Video Tape Recorder), EVS-9 manufactured by Sony Corporation.
00 (trade name) was measured by a remodeling machine.

Further, the productivity is as follows when the protective film is formed.
The evaluation was made by the feed rate of the base film for securing a certain level of productivity when the thickness of the resulting protective film was set to 15 nm.

[0079]

[Table 1]

As shown in Table 1, in each of the present examples, the productivity at the time of forming the protective film was dramatically improved in all cases, and was 8 times or more that in the case of forming the protective film by the sputtering method. This is twice as large as when using a conventional parallel plate plasma CVD apparatus. Also, regarding the still durability, it was found that the sample tape manufactured in this example showed good results.

When the magnetic recording medium of the present invention as described above is applied to the following system, it is possible to secure excellent still durability by improving the surface property of the medium and expect good results. You can

A. Structure of recording / reproducing apparatus As a digital VTR for digitizing a color video signal and recording it on a recording medium such as a magnetic tape, a component type digital VT of a D1 format for a broadcasting station is used.
Composite digital V in R and D2 format
TR has been put to practical use.

The former D1 format digital VTR
Is 1 for the luminance signal and the first and second color difference signals.
After A / D conversion at a sampling frequency of 3.5 MHz and 6.75 MHz, a predetermined signal processing is performed and recording is performed on a magnetic tape. Since the sampling frequency of these component components is 4: 2: 2. 4: 2:
It is also called two methods.

On the other hand, in the latter D2 format digital VTR, the composite color video signal is sampled with a signal having a frequency four times the frequency of the color subcarrier signal, A / D converted, and subjected to predetermined signal processing. , I try to record on a magnetic tape.

In any case, these digital VTs are
Since R is designed on the premise that both are used for broadcasting stations, image quality is given the highest priority, and a digital color video signal in which one sample is A / D converted into, for example, 8 bits is substantially compressed. It is designed to record without doing anything. Therefore, for example, a D1 format digital VTR can obtain a reproduction time of at most about 1.5 hours even if a large cassette tape is used, which is unsuitable for use as a general domestic VTR.

Therefore, here, for example, a signal having a shortest wavelength of 0.5 μm is recorded for a track width of 5 μm, and the recording density is 4 × 10 ⁵ bit / mm ² or more, or 8 × 10 ⁵ bit / mm ² In addition to realizing the above, by using a method that compresses the recorded information in a form that causes little reproduction distortion, recording / reproduction for a long time even when using a narrow magnetic tape with a tape width of 8 mm or less Shall be applied to a digital VTR capable of

The structure of this digital VTR will be described below.

A. Signal Processing Unit First, the signal processing unit of the digital VTR used in this embodiment will be described. FIG. 9 shows the entire structure on the recording side. Digital luminance signal Y and digital color difference Y formed from three primary color signals R, G, B from a color video camera, for example, are provided at input terminals indicated by 31Y, 31U and 31V. The signals U and V are supplied. In this case, the clock rate of each signal is the same as the frequency of each component signal of the D1 format. That is, each sampling frequency is 13.5 MHz, 6.75 MH
z, and the number of bits per sample is 8 bits. Therefore, the input terminals 31Y,
As the data amount of signals supplied to 31U and 31V,
It becomes about 216 Mbps. The data amount of about 167 Mb is removed by the effective information extracting circuit 32 which removes the blanking time data from this signal and extracts only the information of the effective area.
Compressed to ps.

Then, the luminance signal Y of the output of the effective information extraction circuit 32 is supplied to the frequency conversion circuit 33,
The sampling frequency is converted from 13.5 MHz to 3/4 thereof. As the frequency conversion circuit 33, for example, a thinning filter is used so that aliasing distortion does not occur. The output signal of this frequency conversion circuit 33 is
The order of the luminance data supplied to the blocking circuit 35 is converted into the order of blocks. The block forming circuit 35 is provided for the block encoding circuit 38 provided in the subsequent stage.

FIG. 11 shows the structure of a block as a unit of coding. This example is a three-dimensional block, for example, 2
By dividing the screen across the frames, a large number of unit blocks of (4 lines × 4 pixels × 2 frames) are formed as shown in FIG. In addition, in FIG. 11, a solid line indicates an odd field line, and a broken line indicates an even field line.

Of the outputs of the effective information extraction circuit 32, two color difference signals U and V are supplied to the sub-sampling and sub-line circuit 34, and the sampling frequency is converted from 6.75 MHz to half thereof, and then 2 One digital color difference signal is selected for each line
It is combined with the channel data. Therefore, a line-sequential digital color difference signal is obtained from the sub-sampling and sub-line circuit 34. FIG. 12 shows the pixel configuration of the signal subsampled and sublined by the subsampling and subline circuit 34.
In FIG. 12, ◯ indicates a sub-sampling pixel of the first color difference signal U, Δ indicates a sampling pixel of the second dye signal V, and x indicates the position of the pixel thinned by the sub-sample.

The line-sequential output signal from the sub-sampling and sub-line circuit 34 is supplied to the blocking circuit 36. Similar to the one blocking circuit 35, the blocking circuit 36 converts color difference data in the scanning order of the television signal into data in the block order. The blocking circuit 36, like the blocking circuit 35 on the one hand, stores the color difference data (4 lines × 4 pixels × 2 frames).
Convert to the block structure of. Then, the output signals of the blocking circuit 35 and the blocking circuit 36 are combined circuits 3
7 is supplied.

In the synthesizing circuit 37, the luminance signal and the color difference signal converted in the order of blocks are converted into 1-channel data, and the output signal of the synthesizing circuit 37 is supplied to the block coding circuit 38. As the block encoding circuit 38, an encoding circuit (referred to as ADRC) adapted to the dynamic range of each block and a DCT as described later.
(Discrete Cosine Transform)
m) A circuit or the like can be applied. The block coding circuit 38
The output signal from is further supplied to the framing circuit 39 and converted into data having a frame structure. In the framing circuit 39, the pixel clock and the recording clock are changed.

Next, the output signal of the framing circuit 39 is supplied to the error correction code parity generation circuit 40, and the error correction code parity is generated. The output signal of the parity generation circuit 40 is supplied to the channel encoder 41, and channel coding is performed so as to reduce the low frequency part of the recorded data. Channel encoder 41
Output signal of the pair of magnetic heads 43 via recording amplifiers 42A and 42B and a rotary transformer (not shown).
It is supplied to A and 43B and recorded on the magnetic tape. The audio signal and the video signal are separately compression-coded and supplied to the channel encoder 41.

By the above-mentioned signal processing, the input data amount 216 Mbps is reduced to about 167 Mbps by extracting only the effective scanning period, and further it is reduced to 84 Mbps by the frequency conversion, the sub-sample and the sub-line. This data is compressed and coded by the block coding circuit 38 to be compressed to about 25 Mbps, and additional information such as parity and audio signal after that is added, and the recording data amount is 31.56 Mbps.
Becomes

Next, the structure on the reproducing side will be described with reference to FIG. At the time of reproduction, as shown in FIG. 10, first, reproduction data from the magnetic heads 43A and 43B is supplied to the channel decoder 45 via the rotary transformer and the reproduction amplifiers 44A and 44B. The channel decoder 45 demodulates the channel coding, and the output signal of the channel decoder 45 is supplied to the TBC circuit (time axis correction circuit) 46. In this TBC circuit 46, the time-axis fluctuation component of the reproduction signal is removed. The reproduced data from the TBC circuit 46 is the ECC circuit 47.
The error correction code and the error correction using the error correction code are performed. The output signal of the ECC circuit 47 is supplied to the frame decomposition circuit 48.

The frame decomposition circuit 48 separates each component of the block coded data from each other, and
The clock of the recording system is changed to the clock of the pixel system. The respective data separated by the frame decomposing circuit 48 are supplied to the block decoding circuit 49, the restored data corresponding to the original data is decoded in each block unit, and the decoding data is supplied to the distribution circuit 50. The distribution circuit 50 separates the decoded data into a luminance signal and a color difference signal. The luminance signal and the color difference signal are supplied to the block decomposition circuits 51 and 52, respectively. The block decomposing circuits 51 and 52 convert the decoding data in the order of blocks into the order of raster scanning, contrary to the blocking circuits 35 and 36 on the transmitting side.

The composite luminance signal from the block decomposition circuit 51 is supplied to the interpolation filter 53. In the interpolation filter 53, the sampling rate of the luminance signal is 3 fs to 4 fs.
(4fs = 13.5 MHz). The digital luminance signal Y from the interpolation filter 53 is taken out to the output terminal 56Y.

On the other hand, the digital color difference signal from the block decomposition circuit 52 is supplied to the distribution circuit 54, and the line-sequential digital color difference signals U and V are separated into the digital color difference signals U and V, respectively. The digital color difference signals U and V from the distribution circuit 54 are supplied to the interpolation circuit 55 and are interpolated. The interpolator 55 interpolates the data of the thinned lines and pixels using the restored pixel data, and the sampling rate from the interpolator 55 is 2f.
s digital color difference signals U and V are obtained and output terminal 5
6U and 56V are taken out respectively.

B. Block Coding As the block coding circuit 38 in FIG.
C (Adaptive Dynamic Range C
oding) encoder is used. The ADRC encoder detects the maximum value MAX and the minimum value MIN of a plurality of pixel data included in each block, and the maximum value M
The dynamic range DR of the block is detected from the AX and the minimum value MIN, the coding adapted to this dynamic range DR is performed, and the requantization is performed by the bit number smaller than the bit number of the original pixel data. As another example of the block encoding circuit 38, the pixel data of each block is converted into a DCT (Discrete Cosine Tr).
After the transformation, the coefficient data obtained by the DCT may be quantized, and the quantized data may be run-length Huffman-encoded and compression-encoded.

Here, an example of an encoder that uses an ADRC encoder and in which image quality deterioration does not occur even when multi-dubbing is performed will be described with reference to FIG. In FIG. 13, for example, a digital video signal (or digital color difference signal) in which one sample is quantized into 8 bits is input to the input terminal 57 from the synthesizing circuit 37 of FIG. The blocked data from the input terminal 57 is supplied to the maximum value / minimum value detection circuit 59 and the delay circuit 60. The maximum value / minimum value detection circuit 59 detects the minimum value MIN and the maximum value MAX for each block. From the delay circuit 60, the input data is delayed by the time required to detect the maximum value and the minimum value. The pixel data from the delay circuit 60 is supplied to the comparison circuit 61 and the comparison circuit 62.

The maximum value MAX from the maximum / minimum value detection circuit 59 is supplied to the subtraction circuit 63, and the minimum value MIN is supplied to the addition circuit 64. The subtraction circuit 63 and the addition circuit 64 are supplied from the bit shift circuit 65 with a value of one quantization step width (Δ = 1 / 16DR) when non-edge matching quantization is performed with a fixed length of 4 bits. The bit shift circuit 65 is configured to shift the dynamic range DR by 4 bits so as to perform division by (1/16). The subtraction circuit 63 obtains a threshold value of (MAX-Δ), and the addition circuit 64 obtains a threshold value of (MIN + Δ). The threshold values from the subtraction circuit 63 and the addition circuit 64 are supplied to the comparison circuits 61 and 62, respectively. The value Δ defining this threshold is not limited to the quantization step width and may be a fixed value corresponding to the noise level.

The output signal of the comparison circuit 61 is the AND gate 6
6 and the output signal of the comparison circuit 62 is supplied to the AND gate 67. The input data from the delay circuit 60 is supplied to the AND gate 66 and the AND gate 67. The output signal of the comparison circuit 61 becomes high level when the input data is larger than the threshold value. Therefore, the output terminal of the AND gate 66 has the pixel data of the input data included in the maximum level range of (MAX to MAX-Δ). Is extracted. On the other hand, the output signal of the comparison circuit 62 becomes high level when the input data is smaller than the threshold value. Therefore, the output terminal of the AND gate 67 has (MIN to MIN).
Pixel data of the input data included in the minimum level range of + Δ) is extracted.

The output signal of the AND gate 66 is supplied to the averaging circuit 68, and the output signal of the AND gate 67 is supplied to the averaging circuit 69. These averaging circuits 68, 69
Calculates the average value for each block, and the reset signal of the block period from the terminal 70 is averaged by the averaging circuits 68, 69.
Is being supplied to. From the averaging circuit 68, (MAX ~
The average value MAX ′ of the pixel data belonging to the maximum level range of (MAX−Δ) is obtained, and the averaging circuit 69 outputs (MIN).
The average value MIN ′ of the pixel data belonging to the minimum level range of ˜MIN + Δ) is obtained. The subtraction circuit 71 subtracts the average value MIN ′ from the average value MAX ′.
From the dynamic range DR '.

Further, the average value MIN 'is supplied to the subtraction circuit 72, and the average value MIN' is subtracted from the input data passed through the delay circuit 73 in the subtraction circuit 72 to form the data PDI after removal of the minimum value. . The data PDI and the modified dynamic range DR ′ are used by the quantization circuit 74.
Is supplied to. In this embodiment, the number of bits n assigned to quantization is 0 bit (code signal is not transferred),
It is a variable length ADRC that is any one of 1 bit, 2 bits, 3 bits, and 4 bits, and is subjected to edge matching quantization. The allocated bit number n is determined for each block in the bit number determination circuit 75, and the data of the bit number n is supplied to the quantization circuit 74.

The variable length ADRC has a dynamic range D
Efficient encoding can be performed by reducing the number of allocated bits n in a block having a small R ′ and increasing the number of allocated bits n in a block having a large dynamic range DR ′. That is, the threshold values for determining the number of bits n are set to T1 to T4 (T1 <T2 <T3 <
T4), the code signal is not transferred to the block of (DR ′ <T1), only the information of the dynamic range DR ′ is transferred, and the block of (T1 ≦ DR ′ <T2) is (n = 1). The block of (T2 ≦ DR ′ <T3) is (n = 2), the block of (T3 ≦ DR ′ <T4) is (n = 3), and the block of (DR ′ ≧ T4) is The block is (n = 4).

In such variable length ADRC, the threshold values T1.about.
By changing T4, the generated information amount can be controlled (so-called buffering). Therefore, the variable length ADRC can be applied to a transmission line such as the digital video tape recorder of the present invention which requires that the amount of generated information per field or frame be a predetermined value.

In the buffering circuit 76 for determining the threshold values T1 to T4 for making the generated information amount a predetermined value, a plurality of threshold value sets (T1, T2, T3, T4), for example, 3 are set.
Two sets are prepared, and these sets of thresholds are distinguished by the parameter code Pi (i = 0, 1, 2, ... 31). The generated information amount is set to monotonically decrease as the number i of the parameter code Pi increases. However, the quality of the restored image deteriorates as the amount of generated information decreases.

Threshold value T from buffering circuit 76
1 to T4 are supplied to the comparison circuit 77, and the dynamic range DR ′ through the delay circuit 78 is supplied to the comparison circuit 77. The delay circuit 78 delays DR ′ by the time required for the buffering circuit 76 to determine the threshold set. In the comparison circuit 77, the dynamic range DR ′ of the block is compared with each threshold value, the comparison output is supplied to the bit number determination circuit 75, and the allocated bit number n of the block is determined. In the quantizing circuit 74, the data PDI after the minimum value removal via the delay circuit 79 is converted into the code signal DT by the edge matching quantization using the dynamic range DR ′ and the allocated bit number n. The quantization circuit 74 is composed of, for example, a ROM.

The modified dynamic range DR 'and average value MIN' are output via the delay circuits 78 and 80, respectively, and the parameter code Pi indicating the set of the code signal DT and the threshold value is output. In this example, the signal that has been non-edge-match quantized is edge-match quantized newly based on the dynamic range information, so that image deterioration when dubbing is small.

C. Channel Encoder and Channel Decoder Next, the channel encoder 41 and the channel decoder 45 of FIG. 9 will be described. In the channel encoder 41, as shown in FIG. 14, an adaptive scramble circuit to which the output of the parity generation circuit 40 is supplied,
A plurality of M-sequence scramble circuits 81 are prepared, and among them, the M-sequence is selected so as to obtain an output with the least high frequency component and DC component with respect to the input signal. The precoder 82 for the partial response class 4 detection method performs arithmetic processing of 1 / 1-D ² (D is a unit delay circuit). This precoder 82
Is output and recorded and reproduced by the magnetic heads 43A and 43B via the recording amplifiers 42A and 42B, and the reproduction output is amplified by the reproduction amplifiers 44A and 44B.

On the other hand, in the channel decoder 45, as shown in FIG. 15, the arithmetic processing circuit 83 on the reproducing side of the partial response class 4 performs 1 + D arithmetic on the outputs of the reproducing amplifiers 44A and 44B. Further, in the so-called Viterbi decoding circuit 84, the noise-resistant data is decoded by the calculation using the correlation and the accuracy of the data with respect to the output of the calculation processing circuit 83. The output of the Viterbi decoding circuit 84 is supplied to the descrambling circuit 85, the data rearranged by the scrambling process on the recording side is returned to the original series, and the original data is restored. With the Viterbi decoding circuit 84 used in this embodiment, the reproduction C / N conversion is improved by 3 dB as compared with the case of performing decoding for each bit.

D. The traveling magnetic heads 43A and 43B are attached to the drum 86 in an integrated structure as shown in FIG. A magnetic tape (not shown) is obliquely wound around the peripheral surface of the drum 86 at a winding angle slightly larger than 180 ° or slightly smaller than 180 °.
A and the magnetic head 43B are configured to scan the magnetic tape at the same time.

Further, the directions of the gaps of the magnetic head 43A and the magnetic head 43B are inclined to the opposite sides (for example, the magnetic head 43A is inclined + 20 ° with respect to the track width direction, and the magnetic head 43B is inclined -20 °. Is set so that the amount of crosstalk between adjacent tracks is reduced by so-called azimuth loss during reproduction.

17 and 18 show magnetic heads 43A,
This shows a more specific structure when 43B is an integral structure (so-called double azimuth head). For example, the magnetic head 43 is integral with the upper drum 86 rotated at a high speed.
A and 43B are attached, and the lower drum 87 is fixed. Here, the winding angle θ of the magnetic tape 88 is 16
6 °, drum diameter φ is 16.5 mm.

Therefore, on the magnetic tape 88, one field of data is divided into five tracks and recorded. With this segment system, the length of the track can be shortened, and the error due to the linearity of the track can be reduced.

As described above, by performing the simultaneous recording with the double azimuth head, the error amount due to the linearity can be reduced as compared with the case where the pair of magnetic heads are arranged at the facing angle of 180 °. In addition, since the head-to-head distance is small, the pairing adjustment can be performed more accurately. Therefore, with such a traveling system, recording / reproducing can be performed on a narrow track.

[0118]

As is apparent from the above description, in the present invention, plasma CVD is used as the method of forming the protective film.
When the protective film is formed by adopting the method, the substrate travels between the pair of electrodes a plurality of times, or the substrate is spirally wound around a roll passing through the pair of electrodes and travels. With such a structure, it is possible to utilize the plasma generated in the depth direction between the electrodes. Therefore, according to the present invention, when the protective film is formed by the plasma CVD method, the use efficiency of plasma can be increased, and high productivity can be realized while ensuring excellent durability.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a vacuum vapor deposition apparatus used in the manufacture of a magnetic recording medium to which the present invention is applied.

FIG. 2 is a schematic diagram showing a first configuration example of a plasma CVD apparatus used in manufacturing a magnetic recording medium to which the present invention is applied.

FIG. 3 is a schematic diagram showing a modified example of the first configuration example of the plasma CVD apparatus.

FIG. 4 is a schematic diagram showing a second configuration example of the plasma CVD apparatus.

FIG. 5 is a schematic diagram showing a third configuration example of a plasma CVD apparatus.

FIG. 6 is a schematic diagram showing a modification of the fourth configuration example of the plasma CVD apparatus.

FIG. 7 is a schematic diagram showing a configuration of a sputtering apparatus used when forming a protective film.

FIG. 8 is a schematic diagram showing a configuration of a conventional parallel plate type plasma CVD apparatus used when forming a protective film.

FIG. 9 is a block diagram showing a configuration on a recording side of a signal processing unit of a digital VTR which compresses and records a digital image signal in a form such that reproduction distortion is small.

FIG. 10 is a block diagram showing a configuration of a signal processing unit on the reproduction side.

FIG. 11 is a schematic diagram showing an example of a block for block coding.

FIG. 12 is a schematic diagram for explaining subsampling and sublines.

FIG. 13 is a block diagram showing an example of a block encoding circuit.

FIG. 14 is a block diagram showing an outline of an example of a channel encoder.

FIG. 15 is a block diagram illustrating an outline of an example of a channel decoder.

FIG. 16 is a plan view schematically showing an example of the arrangement of magnetic heads.

FIG. 17 is a plan view showing a configuration example of a rotating drum and a winding state of a magnetic tape.

FIG. 18 is a front view showing a configuration example of a rotating drum and a winding state of a magnetic tape.

[Explanation of symbols]

 1 ... Vacuum chamber 2 ... Base film 3 ... Feed roll 4 ... Winding roll 5 ... Cooling can 8 ... Crucible 9 ... Ferromagnetic metal material 10 ... Electron gun 13 ... Shutter 14 ... Oxygen gas inlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Sato, 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Kazumasa Chiba, 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (5)

[Claims] 1. A method of manufacturing a magnetic recording medium in which a metal magnetic thin film and a protective film are sequentially formed on a continuous substrate, wherein the continuous substrate travels between a pair of electrodes a plurality of times when the protective film is formed. And a method for manufacturing a magnetic recording medium. 2. A method of manufacturing a magnetic recording medium in which a metal magnetic thin film and a protective film are sequentially formed on a continuous substrate, wherein the continuous substrate passes between a pair of electrodes when the protective film is formed. A method of manufacturing a magnetic recording medium, characterized in that the magnetic recording medium is spirally wound around a surface and runs. 3. A parallel plate electrode connected to a high frequency power source is used as the pair of electrodes, and the parallel plate electrode and the continuous substrate are arranged in parallel.
A method for manufacturing the magnetic recording medium described. 4. The magnetic recording according to claim 1, wherein parallel plate electrodes connected to a high frequency power source are used as the pair of electrodes, and the parallel plate electrodes and the continuous substrate are arranged substantially vertically. Medium manufacturing method. 5. A method of manufacturing a magnetic recording medium in which a metal magnetic thin film and a protective film are sequentially formed on a continuous substrate, and a cylinder around which a discharge coil connected to a high frequency power source is wound when the protective film is formed. A method of manufacturing a magnetic recording medium, characterized in that a rotating roll is arranged on a central axis of a mold plasma generating chamber, and the continuous substrate is spirally wound around a peripheral surface of the rotating roll to run.