WO2008066215A1

WO2008066215A1 - Self aligned multi turn type apparatus for manufacturing thin film tape

Info

Publication number: WO2008066215A1
Application number: PCT/KR2006/005325
Authority: WO
Inventors: Jai-Moo Yoo; Kook-Chae Chung; Jae-Woong Ko; Young-Kuk Kim; Young-Hwan Kim
Original assignee: Korea Institute of Machinery and Materials KIMM
Current assignee: Korea Institute of Machinery and Materials KIMM
Priority date: 2006-11-28
Filing date: 2006-12-08
Publication date: 2008-06-05
Anticipated expiration: 2009-05-28
Also published as: KR100824670B1

Abstract

Disclosed herein is a self-aligned multi-turn type apparatus for manufacturing a thin film tape, including a pair of reels disposed so as to be spaced apart from each other; a roller assembly located between the pair of reels and comprised of a rotation shaft and a plurality of rollers fixed on the rotation shaft; and a tape-shaped substrate which is unwound from one of the pair of reels, passes around the rollers in a multi-turn manner and is then wound on the other reel, wherein each of the rollers is formed such that a circumferential surface thereof is inclined toward both ends thereof based from a lengthwise center thereof.

Description

SELF ALIGNED MULTI TURN TYPE APPARATUS FOR MANUFACTURING THIN FILM TAPE

Technical Field

The present invention relates to a self-aligned multi-turn type apparatus for manufacturing a thin film tape, and, more particularly, to a self-aligned multi-turn type apparatus for manufacturing a thin film tape, which can uniformly deposit a buffer layer and a superconducting layer on a metal tape, which is used for a superconducting wire, using a multi-turn method.

Background Art

Research on a superconducting wire has been actively conducted since high-temperature superconductors were discovered in 1986. Since high- temperature superconducting power cables can be developed using a long metal tape having a length of 1 km or more, which is fabricated by putting the superconducting wire to practical use, it is possible to supply electric power at high efficiency, high density and high capacity, and high-current transmission can be realized thanks to low loss, so that substations may not be necessary, the insulation cost of cable can be reduced, and civil affairs or electronic interference phenomena, which are caused by radio waves occurring in the vicinity of large cities, can be solved.

Here, the term "superconductor" refers to a phenomenon in which the electrical resistance of a conductor disappears at ultra-low temperatures (below a critical transition temperature) and thus current flows freely without obstruction. Generally, such a thin film tape for a superconducting wire includes a metal tape, a buffer layer, a superconducting layer and a protective layer, and is manufactured by sequentially depositing a buffer layer, a superconducting layer and a protective layer on a metal tape, which is a substrate.

Examples of deposition methods for forming a buffer layer, a superconducting layer, and the like may include pulsed laser deposition (PLD),

E-beam evaporation, R.F. sputtering, D. C. sputtering, thermal evaporation, metal organic chemical vapor deposition (MOCVD), metal organic deposition (MOD), and the like. Further, methods of manufacturing a thin film tape using such deposition methods may include a batch type method and a reel to reel type method.

The former batch type method is a method of forming a buffer layer, a superconducting layer, and the like by winding a metal tape, which is a substrate, on a cylinder and then depositing necessary materials on the metal tape using any one of the above deposition methods while rotating the cylinder.

The batch type method is advantageous in that a thin film tape for a superconducting wire, having a desired length, can be manufactured by adjusting the size of a cylinder, but is disadvantageous in that a deposition process is performed at a high temperature (700 ^°C or higher), and thus a metal tape expands, thereby causing many problems.

The latter reel to reel type method is a method of forming a buffer layer, a superconducting layer, and the like by unwinding a metal tape from one reel, depositing necessary materials on the unwound metal tape and then rolling the deposited metal tape on the other reel. The reel to reel type method is advantageous in that the thickness of the thin film deposited on the metal tape can be freely adjusted and the necessary material can be uniformly deposited on the metal tape because the moving velocity of the metal tape can be controlled. Therefore, recently, the reel to reel type method has been chiefly used in order to manufacture a thin film tape.

However, the reel to reel type method is disadvantageous in that productivity is decreased because the moving velocity of the metal tape is limited.

In order to solve the above problems, a multi-turn type method has been proposed. As shown in FIG. 1, in the multi-turn type method, while a metal tape T is repeatedly wound from one reel 1 to the other reel 2, the metal tape T is diagonally passed around two rollers 4a and 4b several times, which rotate about their rotation shafts 3 a and 3b, respectively. During the passage, a thin film layer is deposited on the metal tape T, which is located between the two rollers 4a and 4b, thereby solving the above problems.

In this case, the rollers 4a and 4b, having the same shape and size, may be provided in a plural number. The rollers 4a and 4b are fitted with the rotation shafts 3a and 3b, respectively, by fitting bearings 5, provided in the center of each of the rollers 4a and 4b, on each of the rotation shafts 3a and 3b and thus the rollers 4a and 4b can smoothly rotate. However, as shown in FIG. 2, since edge flanges 6, serving to prevent members wound on the rollers 4a and 4b from disengaging and to center and align them, are provided on opposite edges of each of the rollers 4a and 4b, there is a problem in that the edge of the metal tape T comes into contact with the edge flange 6, so that the metal tape T is warped or folded by friction, with the result that the multi-turning of the metal tape T cannot be easily performed.

Furthermore, there is a problem in that, when the number of turns of the metal tape T increases, the tension applied to the metal tape T is rapidly increased, thus increasing the work load. As a result, working efficiency is decreased, and, more exceedingly, the metal tape T is torn.

Further, in order to solve the above problems, there is disclosed a method of manufacturing a thin film tape without performing the multi-turning of a metal tape T, by increasing the width of the metal tape T, directly moving the metal tape T from one reel 1 to the other reel 2 while depositing a thin film layer on the metal tape T, and then slitting the metal tape T deposited with the thin film layer at a desired width.

For example, in this method, if a thin film tape that is actually used for a superconducting wire has a width of 4 mm, the thin film tape is manufactured by depositing a thin film layer on a metal tape having a width of 4 cm and then slitting the metal tape deposited with the thin film layer at a width of 4 mm.

However, this method is only a desperate measure and is also problematic in that the quality of the manufactured thin film tape is degraded because the width of the metal tape is large, and thus the metal tape is not uniformly deposited with the thin film layer. For this reason, new type of methods of manufacturing a thin film tape, which can solve the above problems even when the multi-turn type method is used, are keenly required.

Disclosure of the Invention

Technical tasks to be solved by the invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a self-aligned multi-turn type apparatus for manufacturing a thin film tape, by which a thin film layer can be uniformly deposited on a substrate in a longitudinal direction and a width direction, and the problems in which the thin film tape is damaged, folded, warped and ruptured are completely solved because the substrate does not come into contact with the edges of rollers, thus enabling the manufacture o f a high-grade thin film tape regardless of deposition velocity and tape length.

Technical Solution

Li order to accomplish the above object, the present invention provides a self-aligned multi-turn type apparatus for manufacturing a thin film tape, including a pair of reels disposed so as to be spaced apart from each other; a roller assembly located between the pair of reels and comprised of a rotation shaft and a plurality of rollers fixed on the rotation shaft; and a tape-shaped substrate which is unwound from one of the pair of reels, passes around the rollers in a multi-turn manner and is then wound on the other reel, wherein each of the rollers is formed such that a circumferential surface thereof is inclined toward both ends thereof based from a lengthwise center thereof.

Here, each of the rollers has an inclination angle ranging from above 0° to below 90°.

Further, the tape-shaped substrate is made of metal or nonmetal. Furthermore, each of the rollers includes a bearing therein such that the bearing is in rolling contact with the roller, so as to connect the roller with the rotation shaft.

Further, the present invention provides a self-aligned multi-turn type apparatus for manufacturing a thin film tape, including a pair of reels disposed so as to be spaced apart from each other; a roller assembly located between the pairs of reels and comprised of a rotation shaft and a plurality of rollers fixed on the rotation shaft; and a tape-shaped substrate which is unwound from one of the pair of reels, passes around the rollers in a multi-turn manner and is then wound on the other reel, wherein each of the rollers is formed such that a circumferential surface thereof is curved on a lengthwise center thereof and curved and inclined toward both ends thereof.

Advantageous Effects

According to the present invention, since a substrate is aligned along the center of the roller even when a thin film tape is manufactured through a multi- turn type method, the problems in which the thin film tape is damaged, folded, warped and ruptured do not occur, and a coated layer can be uniformly formed thereon, thus manufacturing a high-grade thin film tape.

Brief Description of Drawings

FIG. 1 is a schematic view showing a conventional multi-turn type apparatus for manufacturing a thin film tape;

FIG. 2 is an illustrative sectional view showing a roller used for the conventional apparatus;

FIG. 3 is an illustrative schematic view showing a roller according to Example 1 of the present invention; and

FIG. 4 is an illustrative schematic view showing a roller according to Example 2 of the present invention.

Best Mode for Carrying Out the Invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. 3 is an illustrative schematic view showing a roller according to

Example 1 of the present invention, and FIG. 4 is an illustrative schematic view showing a roller according to Example 2 of the present invention.

A thin film tape for a superconducting wire according to the present invention is manufactured using a conventional reel to reel method. That is, the thin film tape is manufactured by sequentially depositing a buffer layer, a superconducting layer and a protective layer on a substrate, which is a base material, through the multi-turn method shown in FIG. 1.

In particular, in the present invention, the substrate is not limited to metallic material, and thus it is possible to make the substrate using non-metallic materials as well as metallic materials.

The reason why the substrate can be made of non-metal materials as well as metal materials is that the substrate can be uniformly deposited thereon with thin film layers, such as a buffer layer, a superconducting layer, a protective layer, etc. regardless of the deposition velocity over the entire surface of the thin film tape, thus accurately realizing the performance and characteristics of the thin film tape depending on the use thereof.

In this case, the buffer layer serves to impart a buffering function between the substrate and the superconducting layer, which prevents the diffusion of the metal element into the superconducting layer. Also, the buffer layer decreases the lattice mismatch between the substrate and the superconducting layer, and thus enabling the alignment of the substrate to lead to the alignment of the superconducting layer. Examples of deposition materials may include CeO₂,

Y₂O₃, LaMnO₃, SrTiO₃, MgO, YSZ, and the like, and the substrate may be deposited with only one deposition material, or may be deposited with deposition materials in the form of a multi-layered thin film, such as a two-layered thin film or three-layered thin film, if necessary.

Meanwhile, the superconducting layer is chiefly composed of Y₁Ba₂Cu₃O₇-X(YBCO), in which Y may be replaced by rare earth elements. In order to protect the superconducting layer in air, a protective layer, which is chiefly composed of silver (Ag), is deposited on the superconducting layer.

Rollers for manufacturing a thin film tape including these uniformly thin film layers may have the following shapes.

[Example 1] As shown in FIG. 3, the roller 100 for manufacturing a thin film tape according to Example 1 of the present invention is comprised of a plurality of rollers 100 having the same size and form, which is fixed on a rotation shaft 120.

That is, the rotation shaft 120 is provided thereon with the plurality of divided rollers 100 such that they are closely connected with each other, and thus the rollers 100 appear as one roller.

Further, in order to assure the smooth rotation of the rollers 100, bearings 130 are provided between the rotation shaft 120 and the rollers 100 in a number equal to the number of rollers 100.

In this case, the rollers 100 are prepared in a form in which edge flanges ('6' of FIG. 2) are removed therefrom.

In particular, in addition to the elimination of the edge flanges, the rollers 100 are provided with inclined surfaces 101-110, which are tapered toward opposite ends from the centers of the rollers 100.

For example, it will be easily appreciated that the roller 100 is comprised of the plurality of rollers, which are sequentially provided with first inclined surfaces 101, second inclined surfaces 102, third inclined surfaces 103, fourth inclined surfaces L 04, fifth inclined surfaces 105, sixth inclined surfaces 106, seventh inclined surfaces 107, eighth inclined surfaces 108, ninth inclined surfaces 109, and tenth inclined surfaces 110 from the left side of FIG. 3. A pair of roller assemblies A is provided, and is disposed such that they are spaced apart from each other. Then, reels (T of FIG. 1) are positioned at the outsides of respective roller assemblies A. In this configuration, a tape-shaped substrate wound on one reel is unwound and then closely wound on the second inclined surface 102 of an opposite roller. Then, the tape-shaped substrate is closely wound on the third inclined surface 103 of the adjacent one roller, and is closely wound on the fourth inclined surface 104 of the opposite roller, the fifth inclined surface 105 of the adjacent one roller, the sixth inclined surface 106 of the opposite roller, the seventh inclined surface 107 of the adjacent one roller, the eighth inclined surface 108 of the opposite roller, and the ninth inclined surface 109 of an approach roller, in this order. Subsequently, the tape-shaped substrate is wound on the other reel, thereby realizing a multi-turn procedure.

In this procedure, since the tape-shaped substrate moves on downwardly- inclined surfaces of the rollers 100 which are inclined toward each other, the tension of the tape-shaped substrate and the component of the force, which is applied to the tape-shaped substrate in the moving direction of the tape-shaped substrate, is exerted in the inclining direction of the rollers 100, and thus the tape- shaped substrate does not deviate from the rollers 100 while it travels on the rollers.

That is to say, since the tape-shaped substrate, which moves around the rollers, is always located on the inclined surface of the rollers 100, it is possible to prevent the tape-shaped substrate from deviating from the rollers 100. Further, since each of the rollers 100 has no edge flange, there is no problem of extension, damage or rupture of the tape-shaped substrate.

As such procedures are repeatedly conducted, desired thin film layers may be deposited on the tape-shaped substrate while the tape-shaped substrate moves from the inclined surface of one roller to the inclined surface of the other roller, that is, while the multiple turns are carried out.

The thin film layer may be a buffer layer, a superconducting layer, or a protective layer, as described above. The thin film layer may be deposited on the substrate using the same method as conventional deposition methods. That is, examples of the deposition method may include pulsed laser deposition (PLD), E-beam evaporation, R.F. sputtering, D. C. sputtering, thermal evaporation, metal organic chemical vapor deposition (MOCVD), metal organic deposition (MOD), and the like. In this case, the inclination angle of each of the inclined surfaces of the rollers may range from above 0° to below 90°, and more preferably may range from 10° to 45°. This reason why the angle thereof is set within the above range is that the centering of the tape-shaped substrate, that is, the self alignment thereof, is most accurate within this angular range. [Example 2]

As shown in FIG. 4, the configuration of the roller according to Example 2 of the present invention is the same as that of the roller described in Example 1, except that each of the inclined surfaces 101 '— 110' of the rollers 100' in Example 2 is a curved surface having a predetermined curvature radius, rather than a tapered surface.

As shown in FIGS. 4 A and 4B, the curved surface is designed such that the radius (R) of a circle, which is defined by the curved surface, is equal to or larger than the radius (r) of a circle, which is defined by a curved surface formed on the lengthwise center of each of the rollers 100'. In the above Example 2, since the curved surface of the roller is maximally curved and downwardly inclined, when the tape-shaped substrate moves from one reel to the other reel, the force by which the center of the width of the substrate wound on the inclined surfaces 101'~l 10', that is, the curved surfaces of the rollers 100' is forced towards the center of the rollers 100', is maximized, thus smoothly maintaining a multi-turn procedure.

This multi-turn procedure using the rollers 100' is conducted as in Example 1.

Moreover, it is described in Example 1 that the substrate may be deposited thereon with a buffer layer, a superconducting layer, a protective layer, and the like, but, if necessary, in addition to these layers, a ferroelectric layer, a magnetic layer, and the like may further be deposited on the substrate.

In this way, a thin film tape for a superconducting wire can be easily manufactured in a lengthwise or widthwise direction thereof without damage, regardless of length. In the present invention, the thin film tape is manufactured using the rollers 100 and 100' described in Examples 1 and 2. That is, during the multi- turn procedure, heat treatment is conducted, thus forming a plurality of thin film layers on the substrate.

Industrial Applicability

As described above, the self-aligned multi-turn type apparatus for manufacturing a thin film tape is advantageous in that, since a substrate is aligned along the center of roller even when a thin film tape is manufactured through a multi-turn type method, problems in which the thin film tape is damaged, folded, warped and ruptured do not occur, and a coated layer can be uniformly formed thereon, thus manufacturing a high-grade thin film tape.

Claims

Claims:

1. A self-aligned multi-turn type apparatus for manufacturing a thin film tape, comprising: a pair of reels disposed so as to be spaced apart from each other; a roller assembly located between the pair of reels and comprised of a rotation shaft and a plurality of rollers fixed on the rotation shaft; and a tape-shaped substrate which is unwound from one of the pair of reels, passes around the rollers in a multi-turn manner and is then wound on the other reel, wherein each of the rollers is formed such that a circumferential surface thereof is inclined toward both ends thereof based from a lengthwise center thereof.

2. The apparatus according to claim 1 , wherein each of the rollers has an inclination angle ranging from above 0° to below 90°.

3. The apparatus according to claim 1 or 2, wherein the tape-shaped substrate is made of metal or nonmetal.

4. The apparatus according to claim 1 or 2, wherein each of the rollers includes a bearing therein such that the bearing is in rolling contact with the roller, so as to connect the roller with the rotation shaft.

5. A self-aligned multi-turn type apparatus for manufacturing a thin film tape, comprising: a pair of reels disposed so as to be spaced apart from each other; a roller assembly located between the pairs of reels and comprised of a rotation shaft and a plurality of rollers fixed on the rotation shaft; and a tape-shaped substrate which is unwound from one of the pair of reels, passes around the rollers in a multi-turn manner and is then wound on the other reel, wherein each of the rollers is formed such that a circumferential surface thereof is curved on a lengthwise center thereof and curved and inclined toward both ends thereof.

6. The apparatus according to claim 5, wherein the curved surface of the roller is formed such that a curvature radius of a circle, which is defined by the curved surface which is inclined toward the both ends, is equal to or larger than a curvature radius of a circle, which is defined by the curved surface formed on the lengthwise center of each of the rollers.

7. The apparatus according to claim 5 or 6, wherein the tape-shaped substrate is made of metal or nonmetal.

8. The apparatus according to claim 5 or 6, wherein each of the rollers includes a bearing therein such that the bearing is in rolling contact with the roller, so as to connect the roller with the rotation shaft.