JPH04333211A - Manufacture of laminated film capacitor - Google Patents

Abstract

PURPOSE:To obtain a small type laminated film capacitor at low cost by solving the problem of marginal deviation generating on a tabular capacitor bake material formed by pressue-molding a wide metllized film where a plurality of strips of margin are formed in the manufacture of a laminated film capacitor to be widely used in electronic and electric equipment. CONSTITUTION:When a wide metallized film 2, on which a plurality of strips of margin 3 are forme, is wound on a flat plate 1, the film 3 is wound up in such a manner that the part 5, where the margin is not formed, is positioned at the front and the rear ends of the above-mentioned flat plate. As a result, the deviation of margin generated on the tabular capacitor base material, which is formed by applying pressure, can be prevented.

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 multilayer film capacitors widely used in electronic and electrical equipment.

0002

BACKGROUND OF THE INVENTION In recent years, electronic and electrical equipment have become smaller and electronic components have become more densely surface-mounted, and there is a strong demand for multilayer film capacitors to be made smaller and more chip-based.

A conventional method for manufacturing a multilayer film capacitor will be explained below. The conventional manufacturing method for general multilayer film capacitors involves stacking two thin metalized films each having a single band-shaped non-metalized portion (hereinafter referred to as a margin) and winding them into a large cylinder. There are two methods: one method is to take the material and form it into a capacitor base material, and the other is to wind up a wide metallized film with multiple margins into a flat plate and form it into a capacitor base material. Among these, the latter method has extremely high productivity and is attracting attention as an excellent method for manufacturing multilayer film capacitors. In this manufacturing method, a wide metallized film with multiple margins is first wound into a flat plate (winding process), then sandwiched between hot plates and pressurized to form a plate-shaped capacitor base material. (pressure molding process). Then, the plate-shaped capacitor base material is separated from the flat plate and cut into multiple rectangular rod-shaped capacitor base materials (cutting process). Thereafter, metal spraying is applied to both end faces of the rectangular bar-shaped capacitor base material to draw out the electrodes (electrode drawing process), and the capacitor elements are cut into individual capacitor elements (cutting process). After that, lead wires are attached to both thermally sprayed metal surfaces (lead attaching process), and an exterior is applied (exterior process) to produce the product.In the latest chip-type products, suitable wires are attached to the cut surfaces of the divided capacitor elements. A protective film is attached (protective film attachment process) to create a product.

[0004] Here, the winding process in the above conventional manufacturing method will be explained with reference to the drawings.

FIG. 4 is an external view showing the winding process in the conventional manufacturing method. In FIG. 4, 1 is a flat plate;
Rotate the wide metalized film 2 in the direction of the arrow in the figure.
Wind up. On the metallized surface of the wide metallized film 2, a plurality of margins 3 are formed continuously in the length direction, each having a length corresponding to one circumference of the flat plate 1, while being left and right in the width direction of the film. . The wide metallized film 2 wound around the flat plate 1 is formed into a plate-shaped capacitor base material through a pressure forming process.

[0006]

[Problems to be Solved by the Invention] However, as shown in FIG. 5, which is a cross-sectional view of a plate-shaped capacitor base material, the plate-shaped capacitor base material 4 produced by the conventional manufacturing method has
The margin 3 is disposed while being obliquely shifted in the thickness direction of the plate-shaped capacitor base material 4. The dimension L shown in FIG.
This is a representative value representing the magnitude of the deviation of this margin 3.

[0007] The present inventors have found that this phenomenon has already occurred during the winding process, and occurs because the area near the margin of the portion folded back across the front and back width of the flat plate becomes bulky when the metallized film is wound up. It was revealed that this is the case.

[0008] Due to the deviation of the margins created in this way, conventionally it was not possible to cut the capacitor base material into square bar-shaped capacitor base materials unless the distance between each margin was sufficiently large. Furthermore, the deviation of the margins was particularly large near both ends of the plate-shaped capacitor base material, and the margins could not be cut to a predetermined width, so the capacitor base material had to be discarded. This has caused problems such as hindering the miniaturization of multilayer film capacitors and making them expensive.

[0009] In order to solve these problems, the present invention eliminates the deviation of the margins in the plate-shaped capacitor base material, thereby making it possible to reduce the distance between the margins and reducing the loss of the metallized film material. The objective is to provide a small and inexpensive multilayer film capacitor.

0010

[Means for Solving the Problems] In order to achieve this object, the method for manufacturing a multilayer film capacitor of the present invention includes the following steps: A portion where no margin is formed or a portion where the number of margin stripes is significantly reduced is provided, and the metallized film is wound onto the flat plate while being sequentially arranged at the front and rear ends of the flat plate.

[0011]

[Operation] According to the above means, the mechanical properties are made non-uniform,
Because the number of margin stripes, which causes wrinkles and bulkiness at the front and rear edges of a flat plate with a large curvature, is reduced, the metallized film rarely or never becomes bulky at the front and rear edges of the flat plate. There is no margin shift in the plate-shaped capacitor base material.

0012

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of the winding process in the first embodiment of the method for manufacturing a multilayer film capacitor according to the present invention. In FIG. 1, 1 is a flat plate, 2 is a metallized film, and 3 is a margin. 5 is a portion that does not form a margin. The wide metallized film 2 on which a plurality of margins 3 are formed is arranged intermittently with portions 5 that do not form a margin at every length corresponding to half the circumference of the flat plate 1. By rotating it, it is wound up onto a flat plate 1. In addition, the margin 3 is formed in the length direction while being left and right in the width direction of the film every length corresponding to one circumference of the flat plate 1.

Hereinafter, the difference in margin deviation between the first embodiment of the present invention and the conventional example will be explained using a specific example. As the wide metallized film 2, a 300 mm wide polyester film on which aluminum was vapor-deposited was used. This metallized film 2 was provided with a margin 3 of 51 stripes and a portion 5 where no margin was formed at predetermined positions. This was wound around an iron flat plate 1 1500 times, and then formed into a plate-shaped capacitor base material in a pressure forming process. in this case,
The maximum value of the margin deviation (L described above, hereinafter the same) in the plate-shaped capacitor base material was 0.1 mm or less. On the other hand, when winding was performed using the conventional method, the maximum margin deviation was 0.6 mm or more. As is clear from this, the method for manufacturing a multilayer film capacitor according to this example has an excellent effect in eliminating margin deviations in the plate-shaped capacitor base material.

(Embodiment 2) FIG. 2 is an external view of the winding process in a second embodiment of the method for manufacturing a multilayer film capacitor of the present invention. The difference from the embodiment shown in FIG. 1 is that a portion 6 in which the number of margin stripes is significantly reduced is provided instead of a portion that does not form a margin.

In the specific example, a portion 6 in which the number of margin stripes is significantly reduced is a portion in which five margin stripes are formed at a predetermined position. The margin of 5 articles is the same as the margin of 51 articles, with the remaining two margins at both ends, one in the center, and one article each near the middle, and eliminating the other margins. Even in that case, the maximum margin deviation in the plate-shaped capacitor base material was 0.1 mm or less.

According to the second embodiment, it is possible to eliminate margin deviations in the plate-shaped capacitor base material, and by forming continuous margins in an appropriate arrangement, it is possible to wind the film in various processes. In this case, it is possible to continuously monitor the deviation of the margin position in the width direction.

FIG. 3 is a sectional view of a plate-shaped capacitor base material made according to the embodiment of the present invention as described above. As shown in FIG. 3, in the plate-shaped capacitor base material 4,
Since the margin 3 is arranged linearly and parallel to the thickness direction of the plate-shaped capacitor base material 4, the plate-shaped capacitor base material 4 is cut to the minimum width necessary for the design in the subsequent cutting process. It can be cut into square bar-shaped capacitor base materials.

Note that instead of providing a portion where no margin is formed or a portion where the number of margin stripes is significantly reduced, there is a method of forming a non-metalized surface over the entire width of portion 5 in FIG. 1, but this method is less effective and However, due to the difference in Young's modulus between the metallized surface and the non-metalized surface, there is a drawback that the margin position deviates from side to side. Furthermore, even if the margin position is changed to a dogleg shape or the like in a predetermined portion, the deviation of the margin is reduced based on the relationship explained in the section of the effect, but it has been confirmed that the magnitude of the effect is significantly inferior.

[0020]

[Effects of the Invention] As described above, the present invention provides a wide metallized film with a plurality of margins formed intermittently in the length direction, where no margin is formed or where the number of margins is significantly reduced. By winding up the metallized film while sequentially arranging these portions at the front and rear ends of the flat plate, the distance between the margins can be reduced by eliminating the deviation of the margins in the plate-shaped capacitor base material. At the same time, the loss of the metallized film material is reduced, making it possible to realize a compact and inexpensive multilayer film capacitor, and also to realize extremely small multilayer film capacitor chips with an element width of 2 mm or less. It is.

[Brief explanation of the drawing]

FIG. 1: External view of the winding process of the method for manufacturing a multilayer film capacitor in the first embodiment of the present invention.

[Figure 2] Second
External view of the winding process of the method for manufacturing a multilayer film capacitor in the example of

[Fig. 3] A cross-sectional view of a plate-shaped capacitor base material in an embodiment of the present invention.

[Figure 4] External view showing the winding process of the conventional multilayer film capacitor manufacturing method

[Figure 5] Cross-sectional view of a conventional plate-shaped capacitor base material

[Explanation of symbols]

1 Flat plate 2 Metallized film 3 Margin 5 Parts that do not form margins

Claims (1)

[Claims] 1. A method for manufacturing a multilayer film capacitor comprising the step of winding a wide metallized film on which a plurality of strip-shaped non-metalized portions are formed into a flat plate, wherein the metallized film is discontinued in the length direction of the metallized film. Specifically, a portion where the strip-shaped non-metalized portion is not formed or a portion where the number of strips of the strip-shaped non-metalized portion is significantly reduced is provided, and the metalized film is sequentially arranged at the front and rear ends of the flat plate. A method for manufacturing a multilayer film capacitor, which comprises winding up a multilayer film capacitor.