JPH0689431A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the magnetic tape having excellent recording and reproduc ing characteristics at a low production cost. CONSTITUTION:Evaporating sources 5a, 5b are disposed by at least one unit each on the right and left with respect to the vertical line running the center of a cylindrical can 4 at the time of forming a magnetic layer by a vacuum vapor deposition method on a substrate 1 traveling along this cylindrical can 4. The part where the substrate 1 starts to be in contact with the cylindrical can 4 is set in the position lower than the part where vapor deposition starts. The part where the substrate 1 parts from the cylindrical can 4 is set in the position lower than the part where the vapor deposition ends.

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 having excellent high density recording characteristics.

[0002]

2. Description of the Related Art The density of magnetic recording / reproducing devices is increasing year by year, and a magnetic recording medium having excellent short wavelength recording / reproducing characteristics is desired. At present, a coated magnetic recording medium in which magnetic powder is coated on a substrate is mainly used, and the characteristics have been improved so as to satisfy the above-mentioned demand, but it is almost the limit.

Thin film magnetic recording media have been developed to exceed this limit. The thin film magnetic recording medium is manufactured by a vacuum deposition method, a sputtering method, a plating method, etc.
It has excellent short wavelength recording / reproducing characteristics. As the magnetic layer in the thin film magnetic recording medium, Co, Co-Ni, Co-Ni-P, Co-
O, Co-Ni-O, Co-Cr, Co-Ni-Cr, etc. are being studied.

From the viewpoint of application to magnetic tapes, Co-O and Co-Ni-O films formed by oblique vapor deposition are considered to be the most suitable of these, and Co-Ni-O is the most suitable. A vapor-deposited tape having a magnetic layer of has been already put into practical use as a tape for a Hi8 system VTR. An example of a method for manufacturing a vapor deposition tape for Hi8 type VTR will be described below with reference to FIG. (FIG. 2) is an example of the internal structure of the conventional vacuum vapor deposition apparatus for producing the said vapor deposition tape. The substrate 1 made of a polymer material runs along the cylindrical can 4 in the direction of arrow A. Evaporated atoms 7 evaporated from the evaporation source 5 adhere to the substrate 1 to form a magnetic layer. An electron beam evaporation source is suitable as the evaporation source 5, and the evaporation material 6 is filled with an alloy such as Co or Co—Ni. The electron beam evaporation source is used as the evaporation source in order to evaporate a refractory metal such as Co at a high evaporation rate. A shield plate 8 is provided to limit the incident angle of vaporized atoms to the substrate and prevent unnecessary vaporized atoms from adhering to the substrate.
The larger the incident angle of the vaporized atoms to the substrate with respect to the film normal, the higher the reproduction output can be obtained. Reference numeral 9 is a gas inlet for introducing oxygen into the vacuum chamber during vapor deposition. By optimizing the position and the amount of oxygen introduced, a vapor deposition tape having excellent recording / reproducing characteristics and practical characteristics can be obtained. Reference numerals 2 and 3 are a supply roll and a winding roll for the substrate 1, respectively.

[0005]

[Problems to be Solved by the Invention] In the future, the demand for higher output in the short wavelength region will become increasingly stronger for magnetic tapes. One way to meet this demand is to increase the angle of incidence of vaporized atoms on the substrate.

However, conventionally, it has been difficult to stably obtain a high-power medium by simply increasing the incident angle of vaporized atoms to the substrate. Therefore, in order to solve this, the present inventors have made various studies and found that it is extremely effective to provide an underlayer of CoO, CoNiO or the like. However, in order to form the magnetic layer on the underlying layer and the conventional method using the vacuum vapor deposition apparatus shown in FIG. 2, the conventional method using the vacuum vapor deposition apparatus is used. Must be repeated twice. Alternatively, in order to form the underlayer and the magnetic layer by one-time substrate traveling according to the conventional method, a vacuum vapor deposition apparatus provided with two cylindrical cans must be used. When the magnetic layer is formed by any of these methods, the recording / reproducing characteristics are improved, but whichever method is used, the production cost is increased.

Therefore, it has been desired to develop a manufacturing method for forming an underlayer and a magnetic layer while suppressing an increase in production cost as low as possible.

[0008]

Means for Solving the Problems The present invention has achieved the above-mentioned needs, and in forming a magnetic layer by a vacuum deposition method on a substrate traveling along a cylindrical can,
At least one evaporation source is arranged on the left and right with respect to the vertical line passing through the center of the cylindrical can, and the portion where the substrate starts contact with the cylindrical can is located at a position lower than the vapor deposition start portion, and the substrate is cylindrical. It is characterized in that the portion away from the can is located at a position lower than the vapor deposition end portion.

[0009]

According to the method of the present invention, only one cylindrical can is required for vapor deposition of the underlayer and the magnetic layer, and the film can be formed by traveling the substrate once. Therefore, the production cost is greatly increased. It is possible to provide a magnetic tape having improved recording / reproducing characteristics.

[0010]

EXAMPLE An example of the present invention will be described with reference to FIG.

FIG. 1 shows an example of the inside of a vacuum vapor deposition apparatus for carrying out the method of the present invention. The substrate 1 made of a polymer material runs along the cylindrical can 4 in the direction of arrow A. As the evaporation sources, two evaporation sources 5a and 5b are arranged. These evaporation sources and cylindrical can 4
A shield plate indicated by 8a, 8b, 8c, and 8d is disposed between and to prevent unnecessary evaporated atoms from adhering to the substrate. Between the shield plates 8a and 8b and between the shield plates 8c and 8d, openings are formed so that desired evaporation atoms pass from the respective evaporation sources and adhere to the substrate. That is, the evaporated atoms 7a evaporated from the evaporation source 5a pass through the opening 10a between the shield plates 8a and 8b and adhere to the substrate 1. The evaporated atoms 7b evaporated from the evaporation source 5b pass through the opening 10b between the shield plates 8c and 8d and adhere to the substrate. Reference numerals 6a and 6b denote evaporation materials filled in the evaporation sources 5a and 5b, respectively. Reference numerals 9a and 9b are gas introduction ports for introducing a gas such as oxygen into the vacuum chamber during vapor deposition. 16
Reference numerals a, 16b, 16c, and 16d denote free rollers that restrict the traveling of the substrate 1.

The evaporation sources 5a and 5b are arranged as follows. The evaporation source 5a is arranged on the left side of the vertical line 11 passing through the center of the cylindrical can 4, and the evaporation source 5b is arranged on the right side thereof. Moreover, the portion 12 where the substrate 1 starts contacting the cylindrical can 4 is located at a position lower than the vapor deposition starting portion 13, and the portion 14 where the substrate 1 separates from the cylindrical can 4 is located.
However, it is at a position lower than the vapor deposition end portion 15.

The substrate having the above-described structure is caused to travel to evaporate the evaporated atoms for the underlayer from the evaporation source 5a, and the evaporation source 5b.
From the above, by forming a film while evaporating evaporated atoms for the magnetic layer, the underlayer and the magnetic layer can be formed by traveling the substrate once.

Next, a second embodiment of the present invention will be described with reference to FIG. The vacuum vapor deposition apparatus of FIG. 3 is basically the same as that of FIG. 1, but differs from that of FIG. 1 in that two evaporation sources for the magnetic layer are arranged. That is, in (FIG. 3), the underlayer is formed by the evaporation source 5a as in (FIG. 1), but the magnetic layer is formed by the evaporation sources 5b and 5b.
It is formed by c. 6b and 6c are evaporation sources 5 respectively.
It is a vaporized substance filled in b and 5c. Evaporated atoms 7b and 7c evaporated from the respective evaporation sources pass through the openings 10b and 10c of the shield plates 8c, 8e and 8f and adhere to the substrate 1. 9b and 9c are gas inlets. Also in the vacuum vapor deposition apparatus of FIG. 3, the portion 14 where the substrate 1 separates from the cylindrical can 4 is located at a position lower than the vapor deposition end portion 15. By the method as described above, the underlayer and 2
A magnetic layer having a layered structure can be formed by running the substrate once. Moreover, since the magnetic layer has a two-layer structure, it is possible to reduce noise as compared with the medium manufactured by the vacuum vapor deposition apparatus (FIG. 1).

The specific examples of the present invention will be described below, and the recording / reproducing characteristics of the vapor deposition tape produced by the method of the present invention and the vapor deposition tape produced by the conventional method will be compared.

A vapor deposition tape was produced by using a vacuum vapor deposition apparatus having a basic structure as shown in FIG. The cylindrical can 4 had a diameter of 1.5 m, and a polyethylene terephthalate film having a tape thickness of 7 μm was used as the substrate 1. Co was used as the evaporation substances 6a and 6b. Oxygen was introduced from the gas inlet 9a, and a film thickness of 0.
A 02 μm non-magnetic CoO film was formed. Oxygen was also introduced from the gas inlet 9b to form a Co—O partial oxide film having a film thickness of 0.15 μm as a magnetic layer on the CoO film.

The medium produced as described above is slit into a tape shape, and a gap length of 0.15 made of sendust is formed.
The recording / reproducing characteristics were evaluated using a ring type magnetic head of μm. As a result, a commercially available Hi8 system VTR vapor deposition tape manufactured by the conventional method was used with 2 dB at a recording wavelength of 3.8 μm, 5 dB at 0.54 μm, and 0.38 μm.
A reproduction output of 7 dB higher at m was obtained.

As described above, the magnetic tape produced by the method of the present invention has a higher reproduction output than the conventional vapor deposition tape. Further, the productivity is high because the substrate can be manufactured by running the substrate once. Further, since only one cylindrical can is required for vapor deposition, the traveling system of the vacuum vapor deposition device does not become complicated.

As a specific example, the case where Co is used as the evaporation material 6a for the underlayer has been described above. However, the present invention is not limited to this, and the characteristics of the magnetic layer can be obtained even when other metals or alloys are used. If it can be improved, the adoption of the production method of the present invention is effective. Further, as the evaporation material 6b for the magnetic layer, Co-Ni, Co-Fe, Co-Ni-Fe, Co-Cr, Co-Ni-Cr are used.
An alloy or the like may be used. When Co-Cr or Co-Ni-Cr alloy is used as the evaporation material for the magnetic layer, higher reproduction output can be obtained by not introducing oxygen into the vacuum chamber. Although the polyethylene terephthalate film has been described as the substrate, it goes without saying that the same applies to a polymer film such as a polyimide film, a polyamide film, a polyetherimide film, or a polyethylene naphthalate film.

[0020]

According to the present invention, a magnetic tape having excellent recording / reproducing characteristics can be provided at a low production cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of the inside of a vacuum vapor deposition apparatus in an embodiment of the present invention.

FIG. 2 is a diagram showing an outline of the inside of a vacuum vapor deposition apparatus in a conventional example.

FIG. 3 is a diagram showing an outline of the inside of a vacuum vapor deposition apparatus in one embodiment of the present invention.

[Explanation of symbols]

 1 Substrate 2 Supply Roll 3 Winding Roll 4 Cylindrical Can 5, 5a, 5b, 5c Evaporation Source 6, 6a, 6b, 6c Evaporation Material 7, 7a, 7b, 7c Evaporated Atom 8, 8a, 8b, 8c, 8d, 8e, 8f Shielding plate 9, 9a, 9b, 9c Gas inlet port 10a, 10b, 10c Opening part 11 Vertical line passing through the center of the cylindrical can 12 Part where the substrate starts contact with the cylindrical can 13 Deposition start part 14 Substrate Is separated from the cylindrical can 15 Vapor deposition end part 16a, 16b, 16c, 16d Free roller A Substrate traveling direction

Claims (1)

[Claims] 1. When forming a magnetic layer by a vacuum deposition method on a substrate traveling along a cylindrical can, at least one unit is evaporated to the left and right with respect to a vertical line passing through the center of the cylindrical can. The source is arranged, the part where the substrate starts contacting the cylindrical can is located at a position lower than the deposition start part, and the part where the substrate is separated from the cylindrical can is located at a position lower than the deposition end part. Manufacturing method of magnetic recording medium.