JPH01226143A - Manufacture of chip type film capacitor - Google Patents

Abstract

PURPOSE:To obtain an excellent capacitor element with improved adhesiveness and humidity-resistant properties by a method wherein the capacitor elements are provided between a pair of covering sheets and the covering sheets and the capacitor elements are bonded to each other with thermosetting resin prepreg. CONSTITUTION:A pair of metallized plastic films are wound around a drum 1 to form a wound unit 3 composed of a plurality of layers with spacers 2a, 2b and 2c placed in between. Metal sprayed parts 4 for leading out electrodes are formed on both the end parts of the wound unit 3. The wound unit 3 is subjected to a thermal treatment and preliminarily cut into a plurality of capacitor elements 5. Protrusions 6a are formed on a covering sheet 6 and the elements 5 are accommodated in recessed 6b formed by the protrusions 6a. After another covering sheet 7 is applied, a pressurizing and heating curing treatment is performed to form a belt-shape cured unit 8. Solder is applied to the cured unit 8 by flame-coating to form metallic contact parts 10 for leading out external electrodes. The metal sprayed parts 10 are impregnated, thermally cured and, further, polished. Plating is applied to the metal sprayed parts 10 and the sheets 6 and 7 are cut and divided. With this constitution, the excellent capacitor element can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a chip-type film capacitor.

2. Description of the Related Art In recent years, efforts have been made to make electronic devices more multifunctional and smaller, and the electronic components used in these devices have become lighter, thinner, shorter and smaller. A typical example of this is the conversion of electronic components into chips.

Among chip-type capacitors, chip-type film capacitors currently have a larger volume and projected area than chip-type tantalum electrolytic capacitors and chip-type ceramic capacitors. In other words, a chip-type film capacitor is made by winding a pair of metallized plastic films with a thickness of 1.5 to 3 μm around a circular drum with a diameter of 600 mm several hundred times, and then winding the film around the drum several hundred times through a spacer. This process is repeated to form multiple layers, metallized on both end faces, heat treated and pre-cut into semicircular shapes, then cut to predetermined dimensions, and a lead frame is welded to the metallized part to make it suitable for surface mount construction. However, in order to improve shape and dimensional accuracy, chip-type film capacitors are manufactured using molding such as transfer molding (injection molding) as an exterior packaging method.

Problems to be Solved by the Invention However, molding such as transfer molding requires an exterior thickness of 0.5 am or more, and even if the dielectric film is made thinner, the exterior thickness ratio increases, making it difficult to use other chip capacitors. In addition, the investment cost for equipment such as welding machines and molding machines for welding external extraction electrodes such as lead frames is high, and the more the outer thickness is reduced to 1 (1), the more the internal elements are There were drawbacks such as a significant decrease in yield due to the outflow of water, and an increase in costs.

Means for Solving the Problems The present invention aims to provide a method for manufacturing a chip-type film capacitor that eliminates the above-mentioned drawbacks, and is manufactured by the following process sequence.

(b) A winding step of winding a pair of metallized plastic films around a drum a predetermined number of times to form a multi-layered wound product through a spacer; Spray the material,
(c) a process of heat treatment at a predetermined temperature; (d) a process of preliminary cutting into multiple pieces; and (v) a process of forming a capacitor element with a predetermined capacitance. (f) At least one of the exterior sheets made of a base material input heat-curing resin prepreg sheet is cut at a predetermined distance from a pair of strip-shaped base material input heat-curing resin prepreg sheets that have been subjected to mold release treatment on one side and have the same width as the width of the metallicon side of the capacitor element. forming a convex portion or molding it into an uneven shape, accommodating and arranging the capacitor element in the formed concave portion, and performing pressure and heat curing treatment to a predetermined size to form a band-shaped cured product; g) a metallicon step in which the strip-shaped cured product is stacked in multiple stages via spacers wider than the cured product, and then solder is sprayed on both end faces to form a metallicon portion for drawing out external electrodes; A step of impregnating and thermosetting the electrode lead-out metal contact portion with a low-viscosity liquid thermosetting resin; (a) polishing the external electrode lead-out metal contact portion; and (v) plating the polished external electrode lead-out metal contact portion. and (l) cutting and dividing the exterior sheet portion interposed between the capacitor elements. The element is packaged by a pair of exterior sheets made of Xtt thermosetting resin prepreg sheets, at least one of which is formed into a concavo-convex shape, and the exterior sheet and the exterior sheet, and the exterior sheet and the capacitor element are Since it is bonded with thermosetting resin prepreg, it improves adhesion and moisture resistance, and the capacitor element has a viscosity of 20% to further improve moisture resistance.
The treatment is carried out with a low viscosity liquid thermosetting resin having a low surface tension of 0 to 400 CPS and a low surface tension of 20 to 30 dynes. In addition, only a resin curing line and a cutting machine are required as equipment, and the exterior process can be made continuous.

EXAMPLE Hereinafter, one example of the method for manufacturing a chip-type film capacitor of the present invention will be described.

As shown in Fig. 2, a circular drum 1 with a diameter of 600 mm is used as a winding core, and a polyethylene terephthalate film with a thickness of 25 μm is wound a predetermined number of times to form a spacer 2a, and aluminum is deposited on the outer periphery of the spacer 2a as a vapor-deposited electrode. Metalized polyethylene terephthalate film (hereinafter referred to as M PET film) or metalized polyphenylene sulfide film (hereinafter referred to as MI'PS) with a thickness of 1.5 to 3 μm.
A pair of films) are superimposed and wound 500 times to form the
A layer 3a is formed, a spacer 2b is formed on the outer periphery of this first layer 3a in the same manner as described above, and a pair of MPET films or MPPS films are superimposed on the outer periphery of this spacer 2b in the same manner as described above to form the first IJ 3 a. The second layer 3b is formed by winding the second layer 3b, for example, 496 times so as to obtain the same capacitance as .A spacer 2C is formed on the outer periphery of this second layer 3b in the same manner as above, and on the outer periphery of this spacer 2C. Similarly to the above, a pair of MPET films or MPPS films are superimposed and wound, for example, 492 times to obtain the same capacitance as the first layer 3a, to form the third layer 3C.
A spacer 2d is formed on the outer periphery of the layer 3C in the same manner as described above.
A layer winding 3 is formed. Then, zinc or zinc and solder is thermally sprayed onto both ends of this 3N winding 3 to form an electrode lead-out metallic contact portion 4 having a thickness of about 0.2 mm.

Thereafter, heat treatment is performed at a temperature of about 170°C (preferably in the range of 160 to 180°C) for about 2 hours (1 to 3 hours is also acceptable), and after the heat treatment is completed, the three-layer wound product 3 is removed from the circular drum 1 and the As shown in FIG. 3, the capacitor element 5 is first cut into two halves in a semicircular shape, and then finely cut into a width of 3 x m, for example, to produce a large number of capacitor elements 5 having a predetermined capacitance. As shown in FIG.
, 1 to 0.31 m thick) or a heat-resistant film base epoxy prepreg sheet such as a polyimide film or polyphenylene sulfide film. In order to form concave portions 6a, convex portions 6b are continuously formed at predetermined intervals, and in the concave portions 6a formed between convex portions 6b of the exterior sheet 6, as shown in FIG. The capacitor element 5 is fitted and arranged as shown in FIG.
It is heat-treated at a temperature of about 150° C. for about 15 minutes under a pressure of about 10 kg/cd to harden it to a predetermined size, thereby forming a band-shaped cured product 8 covered with a sheet as shown in FIG.

As shown in FIG. 8, the band-shaped cured product 8 thus formed is stacked in multiple stages (in FIG. As shown in FIG.
1) is formed. This external electrode lead metallicon part 10 has a viscosity of 200 to 500 cps and a low surface tension of 20
A liquid epoxy resin with a viscosity ratio of ~30 dynes l of 10 to 3
After impregnating with 0ml and 11g for 3 minutes, it is cured by heating at a temperature of about 120°C for about 2 hours. Thereafter, the external electrode lead-out metallic contact portion 10 is polished to the end of the spacer 9. The surface of the external electrode lead-out metallic contact portion 10 is microporous and has poor solderability due to the impregnated and thermoset resin, so electroless plating with tin, nickel, etc. or solder with a melting point of 180° C. (40% tin) is applied. After that, as shown in FIG. 10, the convex portions 6b of the exterior sheet 6 between the capacitor elements 5 (the portions indicated by the dashed line) are coated with a coating layer of 3.5 mm, for example. A chip-type film capacitor 1 shown in Fig. 1 is made by cutting into 12 pieces to the width of the crane.
Make a large number of 3.

In the above embodiment, as shown in FIG. 4, convex portions 6b are continuously formed at predetermined intervals in order to form concave portions 6a into which capacitor elements 5 are fitted in band-shaped exterior sheet 6, As shown in FIG. 5, the capacitor element 5 is fitted into the recess 6a formed between the convex portions 6b of the exterior sheet 6, and as shown in FIG. Although a case has been described in which a band-shaped exterior sheet 7 made of a planar material is placed, other embodiments shown in FIGS. 11 to 15 are manufactured in the same manner as in the previous embodiment.

The material of the exterior sheet in other embodiments shown in FIGS. 11 to 15 is the same as that of the exterior sheet of the previous embodiment.

In FIG. 11, capacitor elements 5 are continuously placed at predetermined intervals on a flat band-shaped exterior sheet 6.
Then, the exterior sheet 7 is made of the same material as the exterior sheet 6 and has convex portions 7b continuously formed at a predetermined interval so that a concave portion 7a is formed at the position where the capacitor element 5 is fitted. The capacitor element 5 is placed on top of the capacitor element 5.
This is a case in which the holder is fitted into the recess 7a.

In FIG. 12, a band-shaped exterior sheet 6 is continuously molded to have concave and convex portions to form predetermined shaped concave portions 6c and convex portions 6d, and a capacitor element 5 is fitted and arranged in the concave portion 6c of the exterior sheet 6. This is a case where a planar band-shaped exterior sheet 7 made of the same material as the exterior sheet 6 is placed.

In FIG. 13, capacitor elements 5 are successively placed at predetermined intervals on a flat band-shaped exterior sheet 6.
Then, an exterior sheet 7 made of the same material as the exterior sheet 6 and provided with a recess 7e and a protrusion 7f of a predetermined shape so that a recess 7e is formed at the position where the capacitor element 5 fits is placed over the capacitor element 5. This is a case where the capacitor element 5 is placed and fitted into the recess 7e.

FIG. 14 shows that convex portions 6h are continuously formed at predetermined intervals in order to form concave portions 6g into which capacitor elements 5 fit in a band-shaped exterior sheet 6.
The capacitor element 5 is placed in the concave portion 6g formed between the convex portion 6h and the convex portion 6h.
The exterior sheet 6 is made of the same material as the exterior sheet 6, and convex portions 7h are continuously formed at predetermined intervals so that a recess 7g is formed at the position where the capacitor element 5 is fitted. A recess 7g formed between the convex portions 7h of the sheet 7
This is a case where the capacitor element 5 is fitted to the convex portion 6h and the convex portion 7h are joined.

FIG. 15 shows that a band-shaped exterior sheet 6 is continuously molded to have concave and convex portions to provide a recess 61 and a convex portion 6j of a predetermined shape, and a capacitor element 5 is fitted and arranged in the recess 61 of the exterior sheet 6. An exterior sheet 7 made of the same material as the exterior sheet 6 and provided with a recess 71 and a protrusion 7j of a predetermined shape so that a recess 71 is formed at a position where the capacitor element 5 fits is placed on the capacitor element 5. This is a case where the convex portion 6j and the convex portion 7j are joined by placing the capacitor element 5 in the concave portion 71 and joining the convex portion 6j and the convex portion 7j.

In the examples described above, M P E T film or MPPS film was used, but other metallized plastic films may be used, and although a three-layer winding is shown, windings with four or more layers may also be used. It may be.

Furthermore, the shape of the drum is not limited to a circular shape.

Effects of the Invention As mentioned above, the method for manufacturing a chip-type film capacitor of the present invention employs (A) a sheet exterior method, and has an exterior thickness of 0 and 3 a.
Since an exterior sheet with a size of less than m is used, the capacitor can be made smaller than conventional chip-type film capacitors formed by molding of this type.

(13) Since a lead frame is not used, a molding machine and a welding machine are not required, and only a pressure/heat curing line and a cutting machine are required, and the amount of equipment investment can be significantly reduced.

(C) The area of the external electrode lead-out metallic contact portion is large (by applying electroless plating or low melting point solder immersion plating with tin, nickel, etc., solderability by flow, reflow, etc. can be improved.

(D) Dimensional accuracy can be made comparable to that of conventional molding methods.

(E) Since a low viscosity liquid thermosetting resin is used, the moisture resistance of the capacitor can be improved.

(F) Productivity is higher than conventional molding methods due to reduction in capital investment and continuity of the exterior process, and therefore production costs are low and economical.

It has the following effects and has great industrial and practical value.

[Brief explanation of the drawing]

Fig. 1 to Fig. 15 show the manufacturing process of the chip-type film capacitor of the present invention, Fig. 1 is a perspective view of the finished product, and Fig. 2 is a cross-section of the main part of the three-layer wound product wound around a circular drum. Figure 3 is a front view of a 3N roll divided into two semicircular parts, Figure 4 is a perspective view of a band-shaped exterior sheet in which convex portions are continuously formed at predetermined intervals, and Figure 5. 6 is a perspective view of one capacitor element shown in the concave portion of the exterior sheet shown in FIG.
The figure is a perspective view of a planar strip-shaped exterior sheet made of the same material as in FIG. 5, which is in the middle of being placed. FIG. FIG. 9 is a perspective view of a three-tier stack of cured products with external electrode extraction metallic parts formed on the side end faces. FIG. 10 is a strip-shaped cured product just before completion of a chip-type film capacitor. The perspective views and FIGS. 11 to 15 show that at least one of a pair of band-shaped exterior sheets is formed with a convex portion at a predetermined interval or molded into an uneven shape, and a capacitor element is fitted into the formed concave portion. It is a front sectional view of another example arranged. l: Circular drums 2a, 2b, 2c, 2d, 9 Varnish spacer 3: 3-layer winding 3a: 1st layer winding 3b: 2nd layer winding 3C: 3rd layer winding 4: Electrode lead metallicon Part 5: Capacitor element 6.7: Strip-shaped exterior sheets 6a, 6c, 6g, 6L 7a, 7e, 7g. 71: Recesses 6b, 6d, 6h, 6h, 7b, 7d, 7h. 7j: Convex portion 8: Band-shaped cured product 10: External electrode lead-out metallic contact portion 11: Plating N 12; Cutting location 13: Tinop type film capacitor

Claims (1)

[Claims] A winding step of winding a pair of metallized plastic films around a drum a predetermined number of times to form a multi-layered wound product through a spacer, and forming electrode lead-out metallic contact portions on both end faces of the multi-layered wound product. a metallicon step, a step of heat-treating the multilayer winding at a predetermined temperature, a step of preliminarily cutting the multilayer winding into a plurality of pieces after the heat treatment, and forming a capacitor element with a predetermined capacitance. At least one of the exterior sheets made of a heat-curing resin prepreg sheet is cut at a predetermined distance from a pair of belt-shaped base material input heat-curing resin prepreg sheets that have been subjected to mold release treatment on one side and have the same width as the width of the metallicon side of the capacitor element. forming a convex portion or molding the capacitor element into an uneven shape, accommodating and arranging the capacitor element in the formed concave portion, and performing pressure and heat curing treatment to a predetermined size to form a band-shaped cured product; A metallicon process in which the cured product is stacked in multiple stages via spacers wider than the cured product and solder is thermally sprayed on both end surfaces to form an external electrode lead metallicon part, and the external electrode lead metallicon part is coated with a low viscosity liquid thermosetting material. A step of impregnating and thermosetting with a resin, a step of polishing the external electrode lead-out metallic contact portion, a step of plating the external electrode lead-out metal contact portion, and a cutting of the exterior sheet portion interposed between the capacitor elements. A method for manufacturing a chip-type film capacitor, comprising the step of dividing.