JPH0334613B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a metal thin film magnetic recording medium. In recent years, a vapor-deposited tape in which a ferromagnetic metal thin film is formed on a polymer molded substrate by vapor deposition has appeared as a medium suitable for short wavelength recording, and has attracted attention. This medium has long attracted attention as a medium that can theoretically reduce loss at short wavelengths, and has been studied on a laboratory scale for use in digital recording. Recently, it has been put to practical use in some audio applications, and development for video applications is currently active in various fields. When aiming for video applications, it is important to establish production technology that can meet the size of demand.
This field is still in its infancy, and there are many aspects that remain to be expected for future progress. An object of the present invention is to provide a method for preventing the occurrence of wrinkles, which is a problem when obtaining long media. The method currently in practical use involves electron beam evaporation of a ferromagnetic material such as Co or CoNi onto a polymer molded substrate that moves along a rotating support in the presence of a small amount of oxygen. The surface of the substrate used here is higher than that of the substrates used in the conventional roll deposition field.
Smooth and poor handling. Therefore, it has the disadvantage that wrinkles are likely to occur, and a common countermeasure against wrinkles, whether winding in air or in vacuum, is to use a curved rubber roller. This uses the force component generated outward from the center in the width direction of the board, and the thickness of the board is 10 μm.
It is always used when the diameter is less than 10 μm.
At present, when it is larger than m, mechanical loss is large due to its structure, so it is not used much at present. The inventor found that when the evaporation length was increased, 10μ
Even if the diameter is more than m, it is essential to use a curved rubber roller, and I have come across this phenomenon several times where simply having a roller is not enough. In this case, although there is no perfect regularity, the appearance of wrinkles is
If you follow from the start of vapor deposition, wrinkles tend to become more frequent later in the process. They do not occur in the same position. Even if you adjust the contact angle of the curved rubber roller with the substrate, it is almost impossible to eliminate wrinkles. .
It has the following features. The present invention is based on the hypothesis that the main cause of the above is the static electricity of the substrate, and when the substrate is exposed to weakly ionized gas such as DC glow, AC glow, and high frequency glow, wrinkles do not occur within a practical range. This was done based on the discovery that it could be suppressed. The present invention will be explained below using the drawings. The figure shows the configuration of a winding vapor deposition apparatus used in an example of the present invention. As shown in the figure, one or both sides of the polymer molded substrate 2 coming out from the feed shaft 1 are exposed to weakly ionized gas via an intermediate roller 3. 4 and 5 schematically show discharge electrodes. It goes without saying that the weakly ionized gas region should be surrounded by a wall with operating pressure so that the vapor deposition atmosphere can be maintained at a predetermined degree of vacuum. The conditions for the weakly ionized gas need to be maintained at a value with sufficient margin, depending on the type and length of the substrate, as well as the moving speed of the substrate. The charge-free substrate is guided to the surface of a rotating support 7 via a curved rubber roller 6. Therefore, for example, oblique evaporation is performed in which the incident angle is regulated by a mask 9 that limits a portion of the vapor flow generated from the electron beam evaporation source 8. The deposited substrate is wound up on a winding shaft 10. Using this apparatus, the present invention was carried out while winding up a polyethylene terephthalate film having a width of 50 cm. The experimental results are shown in the table below.

[Table] The effect of the present invention was even more remarkable when the experiment was carried out using PET with a width of 80 cm. The present invention was also effective even when the deposition length reached 10,000 m. Furthermore, it was also effective when applied to the formation of perpendicularly magnetized CoCr films on other substrates, sputtering, and ion plating. As described above, the present invention prevents the occurrence of wrinkles,
Since magnetic recording media of excellent quality can be easily obtained, its industrial value is great.

[Brief explanation of the drawing]

The figure is a diagram showing an example of the configuration of main parts of a vapor deposition apparatus used to carry out the present invention. 2... Substrate, 4, 5... Discharge electrode, 6... Curved rubber roller, 7... Rotating support, 8...
Evaporation source.

Claims (1)

[Claims] 1. A magnetic layer is formed by vapor deposition on a polymer molded substrate that moves along a rotating support, and when forming the magnetic layer, the substrate is exposed to a weakly ionized gas, and then a curved roller is used to form the magnetic layer. A method for producing a magnetic recording medium, comprising: guiding the substrate onto the support.