FI78795B - CONNECTOR SAMT FOERFARANDE OCH ANORDNING FOER FRAMSTAELLNING AV DENSAMMA. - Google Patents

Description

1 7879S

Capacitor and method and apparatus for making

The present invention is directed to a capacitor comprising a plurality of layers having opposite edges, each layer comprising a dielectric substrate and a metal film extending from one edge toward the other edge, the layers being arranged so that a metal film of one layer is separated by an adjacent layer of dielectric material. that the edges of the first layer group on one side of the capacitor are outside the second edges of the second layer group and that the edges of the second layer group on the opposite side of the capacitor are outside the second edges of the first layer group, with the first group layers alternating and the edges outside each group are coated with an electrically conductive material to join the metal film layers of each group. The invention also relates to a method of manufacturing such capacitors and to a manufacturing apparatus.

One such method and apparatus is described in U.S. Pat. No. 3,670,378. , then a metallic spray coating is applied to the edges of the base coil to join the metallic films and then the base coil is separated from the rectangular insulating layers to form separate capacitor bodies. The capacitor bodies thus obtained have interwoven metal layers separated by dielectric layers. Vaccines from one group comprising dielectric substrates and metallic films. protrude from one side of the capacitor body, while another group of substrates and films protrude from the other side of the capacitor body. The metal coating is attached so that it electrically connects the metal films of the protruding layer group. Thus, two electrodes or "capacitor plate" arrays are provided which are die-electrically isolated from each other but which are woven together.

In the above arrangement, it sometimes happens that during the winding phase, the layers to be wound intertwine or move off their intended paths, as a result of which one or more layers will be incorrectly positioned with respect to the adjacent layers. If the distance or difference between the coefficient groups is not sufficient, the capacitor may short-circuit or have a lower than intended dielectric strength in one or more regions. Joe the difference is excessive, the capacitance of the capacitor decreases.

It is an object of the present invention to provide a first-class commercial capacitor of the said general type, which has a different structure and a considerably lower cost of the manufacturing method.

Another object of the present invention is to provide said type of match which substantially reduces the possibility of short-circuiting the capacitor during winding as a result of incorrect placement of the metallic and dielectric films.

It is a further object of the invention to provide a method by which the manufacture of capacitors is much faster than is possible with the methods and devices currently available.

Yet another object of the invention is to provide a device adapted to feed the capacitor-forming layers to a drum or transfer wheel directly from a laminating or 3 78795 spreading rollers. Such an arrangement prevents the feedstock from moving in an unsupported state, which reduces the entanglement of the capacitor layers and the resulting misalignment.

To achieve the above objects, the capacitor according to the invention is characterized in that each layer has a metal film-free area adjacent to but separate from one edge, so that a narrow edge film strip remains on the other edge, said strip area separating from the rest of the metal film.

The method according to the invention comprises the steps of forming first and second webs of material each having a dielectric substrate, a metallic film coating and narrow, parallel and longitudinal non-metallic areas, the webs being cut along parallel lines to form strips, the strips being wound on the first and second web strips of the second web from the strips of the second web to form a plurality of adjacent capacitance structure rings, each having alternately metallic and dielectric layers, wherein in each structure the strips of each web project laterally from the metal edge band of the second web for electrically bonding the metallic films of said webs, and the structure is divided into ka across the sections to form capacitors, and the method is characterized in that the webs are cut along parallel lines displaced from the non-metallic areas so that each formed strip has a narrow metallic edge film strip extending inwardly from the other longitudinal edge of the strip to the non-metallic area.

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Finally, the device according to the invention comprises a first and a second storage roll containing webs, each web having a dielectric substrate with a metal well coating and a rotating drum separate from the storage rollers, the device being characterized by first and second laminating rollers separated circumferentially from the drum circumference. unused roll connected to and parallel to each of the laminating rolls to form a pair of rolls with it, and means for cutting the webs into strips before winding the strips onto a drum to form alternating layers of metal and dielectric material, the laminating rollers being sufficiently close and the cutting members are located sufficiently close to the laminating rollers so that the strips are supported substantially along their entire length prior to winding on the drum.

A thin layer of adhesive may be applied to the Taines in at least a portion of the electric field regions of the capacitors, however, the adhesive layer is not applied to the area where the web is cut or to laterally projecting portions of the structure where the metal coating is sprayed. The purpose of the adhesive layer is to fix the lamination sufficiently so that the wound capacitor structure can be processed without disassembling the lamination.

In one embodiment, the webs may be passed through a station where a plurality of laser beams can be burned out to form precisely separated, non-metallic areas of the metal. These non-metallic regions can be made much narrower by laser beam firing than could be achieved with commercially available materials with conventional non-metallic regions that are much wider than necessary in capacitors with low rated voltages.

The invention will be explained in more detail below with reference to the accompanying drawings. Figure 1 is a schematic view of a device according to the invention constructed in accordance with the method and intended for carrying out this method. Figure 2 is a partial cross-sectional view taken along line 2-2 of Figure 1. Figure 3 is a partial plan view on an enlarged scale of the structure of Figure 2. Figure 4 is a partial cross-sectional view on an enlarged scale taken along line 4-4 of Figure 3. Figure 5 is an enlarged, schematic view, partly in cross-section, taken along line 5-5 of Figure 1. Figure 6 is a greatly enlarged partial cross-sectional view of parts of a capacitor according to the invention. Fig. 7 is an enlarged part of Fig. 2 and shows a structure for applying the adhesive to the dough. Fig. 8 is a schematic view showing a laser off-combustion station forming non-metallic areas when the web is unloaded from its storage grate.

Figure 1, to which reference is now made, shows two storage rolls 2, 4 from which the webs A, B are unloaded. Each web A, B comprises a dielectric substrate 6 and a metal film 8. The substrate 6 may be a suitable plastic, such as a resin sold under the trademark "Mylar" ®. The film 8 may be aluminum deposited from the vapor phase, and both the substrate 6 and the metal film 8 are very thin. By way of example but not limitation, the substrate 6 may have a thickness of the order of 25.4 microns or less, while the thickness of the metal foil may often be of the order of 500 A. Each web A, B has a plurality of parallel non-metallic regions 10 it becomes clear what comes to web B. However, it will be appreciated that a similar series of non-metallic regions are fitted to the web A. The non-metallic regions 10 may be preformed on the webs A, B or may be formed by a laser firing method which will be explained later. In any case, the webs pass over a series of rollers for cutting strips or for alternating layering or alternating winding on a drum or a large diameter transfer wheel 20.

More specifically, the web A passes over a freewheeling roll 12a, the axis of rotation of which is displaceable to control the weaving of the web A 6 78795. The idle roll 12a moves inwards and outwards as a unit together with the storage roll 2 under the control of a conventional edge guide sensor (not shown) to adjust the weaving. From the idle roll 12 the web passes the above edge guide sensor to the tension sensing roll 14a. The tension sensing roller sends a signal to an adjustable brake switch (not shown) on which the steal tube 2 is mounted. This adjustment in a closed loop keeps the voltage at some preset value. The device also includes a laminating roll 16a. Between the rollers 14a, 16a there is a web cutting station where the web A is cut into several strips before passing around the laminating roll 16a and wound on a drum or transfer wheel 22. Similarly, the web B passes over the transfer roll 12b and from there to the tension sensing roll 14b 16b, where the roll 12b responds to another edge control sensor (not shown) to adjust the weaving of the web B, while the tension sensing roll 14b signals the adjustable, non-shown brake switch on which the storage roller 4 is mounted to a preset value.

The cutting station of the web B includes a plurality of parallel blades, such as razor blades 21b, which cooperate with the support bar 22b of the polished web over which the web B passes. For the web A, the cut includes parallel razor blades 21a (Fig. 7) cooperating with the web support bar 22a. From each web, the cutting station forms a plurality of strips which immediately advance on the roll 16a and 16b, respectively, and then up onto the drum 20. As a result, the strips are supported along their entire length prior to winding on the drum 20. Because the strips do not move in the space without support, entanglement is avoided and the strips can be accurately positioned on the drum 20. This is in contrast to prior art arrangements that use edge guides, which are sometimes unsatisfactory, to prevent web entanglement.

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The laminating rollers are pressed against the drum or transfer wheel 20, and the razor blades can act directly in the narrow slits of the rollers 16a, 16b. In any case, the cutting arrangement of the webs gives even cuts by means of razor blades without wrinkling of the web material. This is particularly important because uniform cuts are difficult to achieve without wrinkling as thin a web material as is used in the present invention. In the present device, the rollers 16a, 16b may be located either 90 ° apart, as shown in Figure 1, or 180 ° apart.

The web B is cut into a plurality of strips 18b, as shown in Figures 2-4. The web A is also cut to form strips 18a, which, like the strips 18b, eventually form capacitor layers, as shown in Figure 6.

The intersection lines of the web B are offset from the non-metallic areas 10 to form metallic edge film strips 24 at one edge of each strip 18b. However, a similar cut is made at the web A, with the difference that the cut line of each blade 21a is offset from the cut line compared to Fig. 3 to form similar edge film strips 24 on the strips 18a. If the blade 21b is located on the left side of the metal-free area 10 when cutting the web B (see Fig. 3), then the blade 21 is located on the right side of the adjacent metal-free area for the web A, as indicated by the arrows 21aa in Fig. 3.

The strips are placed simultaneously on the drum 20 to form the layered pattern shown in Figure 5. In this case, several rings 30 with a capacitor structure are formed, from which separate capacitors can be manufactured. Figure 5 shows only one of the rings 30 in cross section for the sake of clarity. In addition, the sources of the different strips, i.e. from the stock roll A or B, are shown together in the structure 30 of Figure 5. It will also be seen that the strips are not shown to scale, but rather are considerably abbreviated. However, next to the drum 20 8 78795 there is a first winding of layers A, as shown by the five lowest layers of Figure 5. The strips are then alternately deposited and shifted from each other while being wound on a drum 20 to form the pattern shown in the alternating layers A and B of Figure 5. A further group of layers is then wound on top of the group of alternating layers A and B. The inner and outer layers act as reinforcements, while the interwoven layers A and B or strips form the active part of the capacitor structure.

Each individual ring 30 can be removed from the drum 20 and their sides 32, 35 are coated in a conventional manner with a metallic spray coating (Figure 6). The ring 30 can then be cut at right angles to the edges 32, 34 to form a capacitor assembly. This piece can then be re-cut in the transverse direction to form separate capacitor units.

Figure 6 shows an enlarged cross-sectional pattern through several alternating layers of a capacitor. It can be seen that on the other side of the capacitor, the metallized films 8a and the base 6a project laterally outside the adjacent edges 36 of the layers 18b. The metallized spray coating 40 connects the electrically metallized films 8a to form a series of capacitor electrodes or plates, this being made possible by the space between the layers or strips 18a. The space between the upper left metal coating 40 of the upper part of Fig. 6 and the metallized layer 8b of the strip 18b is at least the width of the non-metallic area 10 plus the width of the metallic edge film strip 24. The strip 24 is thus in fact a "floating" electrode. Thanks to the floating electrode formed by the strip 24, the entire width of the metallized area is exploited; dielectric separation along the surfaces of the layers, which reduces the possibility of a short circuit or capacitor change from a predetermined value.

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On the other side of the capacitor, the layers 18b, as shown at the bottom of Figure 6, protrude from the edge 37 of the layers 18a to receive the right-hand metal jet coating 40 shown at the bottom of Figure 6. The metallic edge film strip 24 in the lower part of Figure 6 is located on top of the layer 18a and likewise acts as a "floating" electrode, so that the metal-free areas 10 can be fully utilized, as described above.

In a modified form of the invention shown in Figure 7, a suitable thin adhesive can be applied to the web A by an applicator 50 located immediately before the point where the cutting step is performed. Epoxy resin is one type of adhesive that can be used, but the invention is not limited thereto. The adhesive is applied in the cutting area or web dimension area where the metal spray coating is applied. The purpose of the adhesive, if required, is to lock the lamination together after this has been wound on the drum 20 so that the structures 30 can be handled without unloading the lamination. The adhesive can be applied with a film thickness substantially less than 25.4 μm, and the adhesive can thus be used without substantially reducing the effective capacitance to volume ratio.

The web material used in the present invention can be purchased equipped with non-metallic areas. However, these metal-free ranges are usually slightly larger than is required for low voltage capacitors. As shown in Fig. 8, the non-metallic areas 10 can therefore be formed while the web A or B is unloaded from the storage roll. This can be accomplished by passing the web through a laser degassing station 52 where laser beams 53 can be used to burn off the precipitated metal and form a very narrow metal-free area 10 that is much narrower than commercially available webs. Material costs are thus reduced, as is the size of the capacitor. The stress sensing and edge control control systems used in the present invention are available from Advanced Web Systems, Inc. 4973 Colt Road, P.O. Box 6025, Rockford, Illinois 61125.

Claims (13)

A capacitor comprising a plurality of layers (16a, 18b) having opposite edges, each layer comprising a dielectric substrate (6) and a metal film <8) extending from one edge toward the other edge, the layers being arranged so as to: that the metal film <8) of one layer is separated from the metal film of the adjacent layer (6) by the layers (18a, 18b) being displaced so that on the other side of the capacitor the edges of the first layer group <18a) are outside the second edges of the second layer group (18b), and that on the opposite side of the capacitor the edges of the second layer group (18b) are located outside the second edges of the first layer group (18a), the first group layers (18a) alternating with the second group layers (18b) and the edges outside each group are electrically conductive coated (40) for joining the metal film layers of each group, known u in that each layer comprises a metal film-free area (10) adjacent to but separate from one edge, so that a narrow edge film strip (24) remains at the other edge, said area of the strip separating from the rest of the metal film (8). Capacitor according to claim 1, characterized in that the non-metallic region (10) and the narrow, metallic edge film (24) together have a width which is a small fraction of the width of the associated layer. Capacitor according to claim 2, characterized by reinforcement layers on opposite sides of the first and second layer groups. A method of manufacturing capacitors, the method comprising the steps of forming first and second webs of material (A, B) each having a dielectric region of 78795 (6), a metallic Jcal coating (Θ), and narrow, parallel, and longitudinal non-metallic regions (10) , the webs are cut along parallel lines to form strips, the strips are wound from the first and second doughs alternately on a drum (20), and during winding strips of the second web are transferred from the strips of the second web to form a plurality of adjacent capacitance rings (30). ), wherein in each structure the layers of the strips of each web protrude laterally from the metal edge film strip (24) of the strips of the other web, the capacitance structure rings (30) are separated, the laterally projecting portions of each structure are coated with a metallic material (40) for electrically joining the metallic films of said webs, and the structure is divided across the strips to form capacitors, characterized in that the webs are cut along parallel lines displaced from the non-metallic areas so that each formed strip has a narrow metallic peripheral strip (24) extending inwardly from the strip from the longitudinal edge to the metal-free area. Method according to Claim 4, characterized in that the webs are subjected to tension over both web lengths and the webs are cut to tension lengths. A method according to claim 5, characterized in that an adhesive is placed between the strips of each structure during their winding. Apparatus for manufacturing capacitors, comprising first and second storage rolls (2, 4) containing webs, each dough having a dielectric region (6) provided with a metal film coating (8) and a rotating drum (20) separate from the storage rollers, characterized by i2 78795 of a first and a second laminating roll (16a, 16b) separated in the circumferential direction with respect to the circumference of the drum from an unused roll (14a, 14b) connected to each laminating roll and arranged separately therefrom and parallel thereto to form together with it. lapar, and means (21a, 21b) for cutting the webs into strips before the strips are wound on the drum, alternately forming layers of metallic and dielectric material, the laminating rollers (16a, 16b> being located sufficiently close to the drum (20) and the cutting members (21a, 21b) being sufficiently close to the laminating rolls, so that the strips are supported mainly by o in length before winding on the drum. Device according to Claim 7, characterized in that the lamination rollers (16a, 16b) are separated from each other by approximately 90 degrees on the circumference of the drum (20). Device according to Claim 7, characterized in that the laminating rollers (16a, 16b) are separated from each other approximately 180 by the circumference of the drum (20). Device according to claim 8 or 9, characterized by means (50) between the rollers of a pair of rollers for applying the adhesive to the surface of the web. 10,78795 Device according to Claim 10, characterized in that the gluing means (50) are arranged between the tension-sensing roller and the cutting means. Apparatus according to claim 11, characterized by a laser (1) for forming a plurality of longitudinal parallel and non-metallic areas in the web before cutting the web. 13,78795