JP2008140798A - Metallization film and metallization film capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallization film capacitor exhibiting good current resistance while suppressing individual variation in current resistance. <P>SOLUTION: In the metallization film capacitor, a metal thin film of at least one layer is formed on one side of a dielectric film and processed to have a corrugation at the opposite side end portions for forming a metallicon electrode. A relation is determined between the pitch length and the amplitude of a wave at the side end portion of the dielectric film for forming a margin and the pitch length and the amplitude of a wave at the side end portion not forming a margin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metallized film capacitor having particularly low dielectric loss tangent (hereinafter referred to as “tan δ”) characteristics and excellent current resistance, and a metallized film used for such a capacitor.

  With the rapid development of digital home appliances in recent years, the characteristics of capacitors that are used in large numbers on semiconductor substrates inside devices have come to be regarded as important. In particular, in a digital device such as a thin display, it is necessary to increase a current flowing through a semiconductor substrate inside the device as the function increases, and an improvement in current resistance of a capacitor is required.

  Conventionally known methods for improving the current resistance of a capacitor include a method for suppressing self-heating of the capacitor and a method for increasing the mechanical strength of the metallicon junction of the capacitor. For example, as a method for suppressing self-heating, there is a method for suppressing Joule heat generated by increasing the thickness of a metal thin film formed on a dielectric film to form a low resistance film.

In addition, as a method of increasing the mechanical strength of the metallized joint portion of the capacitor, for example, a method of forming a notch in the side end portion of the film using laser light (see Patent Document 1), or a constant angle with respect to the shaft A method of increasing the contact area with the metallicon when the films are laminated and increasing the bonding strength by forming a film-side end in a sine wave shape using a film slitter having a bending cutter (Patent Document 2) Have been proposed).
Japanese Patent Laid-Open No. 2-198122 JP 2005-324315 A

  By the way, the conventional method of thickening a metal thin film formed on a dielectric film to make it a low-resistance film is to reduce the energy of partial destruction due to uneven thickness of the dielectric film and short-circuit current generated in the defective part. In order to increase the size, there is a problem that dielectric breakdown tends to occur and the life of the capacitor is shortened.

  Further, in the method of Patent Document 1 in which the bonding strength of the metallicon is increased, the bonding strength between the metallicon and the film is increased by increasing the contact area of the metallicon, but the current resistance characteristics of the obtained capacitor vary greatly. There was a drawback. Furthermore, with the recent increase in current of devices, the current resistance of film capacitors has become an issue.

  The present invention has been made to solve the above-mentioned drawbacks of the prior art, and the present invention is a metallized film capacitor having a good bonding strength between a metallicon and a metal thin film, a low tan δ, and an improved current resistance. And a metallized film constituting such a metallized film capacitor.

At least one metal thin film is formed on one surface of the dielectric film, and the metallized film is formed so that both side end portions of the dielectric film have a wave shape.
Further, in the side edge processed into the corrugated shape of the dielectric film, the pitch length of the corrugated shape of the side end portion forming the margin and the pitch of the corrugated shape of the side end portion not forming the margin. You may form so that length may differ.

  Further, in the side edge processed into the corrugated shape of the dielectric film, the amplitude of the corrugated shape of the side end forming the margin is Lm1, and the amplitude of the corrugated shape of the side end not forming the margin is When Lm2, the relationship between Lm1 and Lm2 may be formed so that Lm1> Lm2.

  A metallized film capacitor formed by laminating one of the metallized films has good bonding strength between the metallicon and the metal thin film, and has little variation in production. Further, tan δ is low, and the current resistance can be improved.

  According to the metallized film of the present invention, it is possible to stably provide a metallized film capacitor having good metallicon bonding strength and good current resistance.

  An embodiment of the present invention will be described with reference to the drawings. Note that the drawings are schematic diagrams for easy understanding of the film structure of the product of the present invention, and therefore the size and the like are different from the actual ones.

  FIG. 1 is a diagram showing a structure of a metallized film according to the present embodiment. 1A is a plan view and FIG. 1B is a cross-sectional view. The metallized film (1) of the present invention forms a metal thin film (3) on the upper surface (7) of the dielectric film (2), and the upper surface (7) of one side end (10) of the dielectric film (2). ) Is provided with a margin (4) where no metal thin film is formed. A metal thin film is formed on the upper surface (7) of the other side end (12). Further, both side end portions (10, 12) of the dielectric film are cut into a corrugated shape.

  In the present specification, the surface on which the metal thin film (3) is formed on the dielectric film (2) is the upper surface (7), the opposite surface is the lower surface (8), and the side where the margin (4) is provided. The side end portion (10) is the margin side end portion (10), the side end portion (12) on the side with the metal thin film is the electrode side end portion (12), and the margin side end portion (10) and the electrode side end portion (12 ) Are referred to as a margin side end surface (11) and an electrode side end surface (13), respectively.

  Further, the distance from the top of the peak of the corrugated shape to the bottom of the trough at the side end portion cut into the corrugated shape is called amplitude. There are also amplitudes Lm1 (20) on the margin side end (10) side and amplitude Lm2 (21) on the electrode side end (12) side. In addition, a wave-shaped peak means the part protruded to the outer side of the dielectric film (2), and a trough means the part dented to the inner side of the dielectric film (2).

  The width (6) of the margin (4) is the distance between the top of the dielectric film (2) (7) and the peak of the corrugated peak at the margin end (10) to the metal thin film (3). Say. The width (5) of the metal thin film refers to the distance from the top of the corrugated crest of the electrode end (12) to the margin (4) on the upper surface (7) of the dielectric film (2).

  The margin side end portion (10) is a portion longer than the amplitude Lm1 (20) and shorter than the margin width (6) from the margin side end surface (11). The electrode side end portion (12) is a portion longer than the amplitude Lm2 (21) from the electrode side end surface (13) and shorter than the width (5) of the metal thin film.

  Next, the material and manufacturing method of each part of this metallized film will be described. The dielectric film (2) that can be used for the metallized film of the present invention is not particularly limited as long as it is a film substrate on which a conductive metal can be deposited, but polyethylene, non-stretched or stretched polypropylene, polymethylpentene, cycloolefin. Organic polymer film composed of a single polymer, a mixture of two or more of these, and a polymer alloy From the viewpoint of excellent withstand voltage characteristics, tan δ, and insulation resistance characteristics when a capacitor is formed, an unstretched or stretched polypropylene film is particularly preferably used.

  Moreover, even if various coatings, sputtering, CVD, and vapor deposition films are provided on the vapor deposition surface side of these film bases in order to improve various characteristics such as increasing the dielectric constant, as long as the object of the present invention is achieved. The kind of film base material is not particularly limited.

  The polypropylene film preferably used as the film substrate of the dielectric film (2) is a film made of a copolymer of propylene and another α-olefin (for example, ethylene, butene, etc.) in addition to a film made of a homopolymer of polypropylene. Or a film made of a blend of polypropylene and another α-olefin polymer (for example, polyethylene, polybutene, etc.).

  Moreover, the additive contained in the film base material of the dielectric film (2) is not particularly limited, and may be appropriately selected and added as long as the target properties of the present invention are not affected. .

  The film substrate surface may be subjected to surface treatment such as corona discharge treatment, flame treatment, plasma treatment, or lamination of an adhesive coating layer, a resin coating layer, a resin layer by melt extrusion, etc. It is preferable to perform the corona discharge treatment from the viewpoint that it is easy to make the wet tension uniform.

  The thickness of the dielectric film used in the present invention is not particularly limited and can be appropriately determined according to the application in which the capacitor is used. From the viewpoint of reducing the size and increasing the capacity of the capacitor, the thickness is preferably 0.1 μm or more and 10 μm or less. The thickness is preferably 2 μm or more and 7 μm or less.

  Examples of the material of the metal thin film (3) that can be used for the metallized film of the present invention include aluminum, zinc, tin, nickel, chromium, iron, copper, titanium, and alloys containing these. From the viewpoint of the electrical characteristics and productivity of the capacitor, zinc, aluminum, or an alloy containing them is preferable. More preferably, the metal layer contains 90% by mass or more of aluminum. Specifically, it is preferable from the viewpoint of moisture resistance to use aluminum alone or an aluminum alloy containing 90% by mass or more of aluminum.

  The metal thin film (3) can be formed by, for example, a vacuum film forming method. There are various vacuum deposition methods such as vacuum deposition, sputtering, laser brazing, etc., which can be determined appropriately depending on the type of metal thin film to be formed, but vacuum deposition is effective from the viewpoint of production efficiency. .

  The thickness of the metal thin film (3) is not particularly limited and can be appropriately determined according to the application, but is preferably 5 nm or more and 300 nm or less from the viewpoint of miniaturization, high frequency characteristics, moisture resistance, and the like. The metal thin film (3) may have a so-called heavy edge structure in which the film thickness of the metal thin film (3) is inclined from one side end portion forming the metallicon electrode to the opposite side end portion facing each other. . Further, the metal thin film (3) may have a structure in which one or more metal thin films are laminated for the purpose of imparting moisture resistance and conductivity.

  The film resistance value of the metal thin film (3) is preferably in the range of 0.5 to 50Ω / □. If the film resistance is less than 0.5Ω / □, the original capacitor characteristics may not be obtained, for example, a self-healing failure occurs and the insulation resistance deteriorates. If it exceeds 50Ω / □, the series equivalent resistance may increase and tan δ may deteriorate. In order to make the film resistance within the above range, it is possible to adjust by means such as control of the thickness of the metal thin film and selection of the metal material.

  “□” indicates that the sample is square. When the four-terminal method is used when measuring the resistance value, if the sample is a square, the measured resistance value is constant regardless of the size of the sample. Therefore, for example, 50Ω / □ represents that the resistance value measured for the square sample is 50Ω.

  As a method of forming a corrugated shape at the side end of the metallized film (1) in the present invention, there are, for example, a method using a slitter device and a method using laser light. As a method using a slitter device, a corrugated shape can be formed by cutting a film using a slitter device provided with a curved cutter. On the other hand, the method using laser light is a method of forming a corrugated shape by irradiating laser light so as to draw a wave on the side edge of the film. From the viewpoint of mass production, the former slitter device is used. The method used is preferred.

  FIG. 2 is a cross-sectional view showing the structure of the metallized film capacitor (100) according to the present embodiment. More specifically, two metallized films (1 and 50) are overlapped and wound twice, and a metallicon (110) treated at both ends is cut along the core (101). It is.

  The metallized film (50) is a metallized film provided with a margin (4) on the side end surface opposite to the metallized film (1). After the metallized film capacitor (100) of the present invention is laminated and wound so that the margins of the metallized film (1) and the metallized film (50) are alternately opposite to each other, 110) It has been processed. In FIG. 2, two metallized films are paired and wound twice. However, a structure in which a plurality of metallized films are laminated and wound may be used. May be.

  Between the laminated metallized film (1) and metallized film (50), a margin (4) and a shift width (106) are provided in the metallized film for the purpose of ensuring an insulation distance (102). As described above, the margin (4) is a distance from the margin side end surface to the metal thin film (3). In the two metallized films laminated so that the margins (4) are staggered, the shift width (106) is the margin side end face of one metallized film and the electrode side end face of the other metallized film when laminated. Is the distance.

  As for the margin (4), it is preferable that the insulation distance (102) is determined from the viewpoint of the electrical characteristics of the capacitor, and the width is 0.1 to 5 mm. On the other hand, when the margin side end of the metallized film (1) is outside the electrode side end of the metallized film (50), the margin side end is a hindrance to intrusion of the metallicon (110). Become. As a result, the junction area (for example, the portion denoted by reference numeral 111 in FIG. 2) between the metallicon (110) and the metal thin film (3) is reduced, causing a problem that the current resistance characteristics of the capacitor are deteriorated.

  Therefore, it is preferable to provide the shift width (106) so that the margin side end of the metallized film (1) is inside the electrode side end of the metallized film (50). Here, the inside means the direction in which the margin side end of the metallized film (1) and the margin side end of the metallized film (50) approach. Furthermore, if the displacement width (106) is too large, the strength of the metallized film capacitor is weakened and causes deformation, so 0.1 to 2 mm is preferable.

  Subsequently, the structure of the metallized film capacitor according to the present embodiment will be described in detail below. As described above, with only the conventional technique of cutting one side edge of a metallized film into a wave shape, when a large number of capacitors are produced, individual current resistance varies greatly, It became clear that the electric current was insufficient.

  The inventors have found that the cause of the lack of current resistance is due to the bonding state between the side end of the metallized film and the metallicon. Furthermore, the inventor has laminated a plurality of metallized films having a corrugated shape on both ends of the dielectric film and wound them to form a metallized film capacitor, thereby increasing the bonding strength between the film and the metallicon. It was found that the variation in individual current resistance was small and the current resistance was improved.

  According to the study, the electrode-side end of the metallized film has a corrugated shape, and as shown in FIG. 2, the film collapses (for example, a portion indicated by reference numeral 115 in FIG. 2). Further, by forming the side end portion forming the margin into a corrugated shape, a film collapse (for example, a portion indicated by reference numeral 114 in FIG. 2) also occurs in the corrugated portion at the margin side end portion. As a result, a gap is secured between the films (for example, a portion 116 in FIG. 2).

  Since the shift width (106) is set, the electrode side end portion is set to be easily joined to the metallicon, but the margin side end portion is also preferably joined to the metallicon. Of course, if the metallicon to be joined to the margin side end is joined to the metal thin film of the metallized film, the electrodes will not conduct each other, so that it will not serve as a capacitor. Therefore, the metallicon to be joined to the margin side end must not come into contact with the metal thin film of the metallized film.

  It was considered that the variation in the current resistance characteristics found by the inventors was caused by insufficient bonding between the metallicon and the margin side end. Thus, by applying a corrugated cutting process to both the electrode side end and the margin side end, it is possible to sufficiently secure the bonding between the margin side end and the metallicon.

  By doing in this way, compared with the metallized film which performed the corrugated cutting process only to one side edge part of the metallized film conventionally performed, as mentioned above, between the films in a metallicon junction part. A gap is secured in the metal, making it easier for the metallicon to enter. Further, the margin side end portion and the metallicon can be sufficiently joined. As a result, the contact area between the metal thin film of the metallized film and the metallicon is increased, the electric conduction is good, and the joint strength of the metallicon is further strengthened.

  Next, the corrugated shape of the metallized film will be described with reference to the drawings. FIG. 3 is an enlarged view showing a wave shape at the side end when the metallized films (1) and (50) are in a laminated state. The front of the drawing is a metallized film (1), and the rear is a metallized film (50). Both have an upper surface in front of the drawing.

  A part of the metal thin film (3) of the metallized film (1) and the boundary (16) between the margin (4) are visible. Here, the pitch length is defined. The pitch length is the distance from the top of one peak of the corrugated shape at the side edge to the top of the next peak.

  Similarly to the case of the wavelength, there are two pitch lengths Lp1 (30) at the margin side end and pitch length Lp2 (31) at the electrode side end. In FIG. 3, the pitch length Lp1 (30) at the margin side end of the metallized film (1) and the pitch length Lp2 (31) at the electrode side end of the metallized film (50) are shown.

  When the pitch length Lp1 (30) at the margin side end and the pitch length Lp2 (31) at the electrode side end are the same length, the corrugations of the metallized films (1) and (50) as shown in FIG. The shape of the metallized film (50) is wound in an overlapping manner in the longitudinal direction, and the corrugated shape at the electrode side end of the metallized film (50) becomes a shadow of the corrugated shape at the marginal end of the metallized film (1). May interfere.

  As a result, the metal thin film of the metallized film is poorly bonded to the metallicon, and the current resistance is reduced. Therefore, it is preferable that the pitch length Lp1 (30) of the margin side end portion is different from the electrode side end portion pitch length Lp2 (31).

  Further, either Lp1 or Lp2 may be longer, but Lp1 / Lp2 is preferably 0.01 or more and 100 or less. More preferably, Lp1 / Lp2 is 0.2 or more and 5 or less. This is because if one of them is too long, the effect of forming the corrugated shape at the side end is lost. Further, when both Lp1 and Lp2 are too long, it is impossible to efficiently secure a gap between the films as in the conventional method in which the corrugated cutting process is not performed. Therefore, both Lp1 and Lp2 are preferable. Is preferably 0.1 mm or more and 10 mm or less, more preferably 1 mm or more and 5 mm or less.

  FIG. 4 shows a side end portion of the laminated metallized film as in FIG. The state which the metallized film (50) has overlapped on the metallized film (1) is shown. 4A is a plan view and FIG. 4B is a cross-sectional view. In the plan view of FIG. 4A, the waveform shape of the margin side end portion of the metallized film (50) and the waveform shape of the electrode side end portion of the metallized film (1) are visible. Yes.

  As described with reference to FIG. 1, the amplitude of the wave shape at the margin side end is Lm1 (20), and the amplitude of the wave shape at the electrode side end is Lm2 (21).

  Now, FIG. 4 shows a case where Lm1 (20) is smaller than Lm2 (21), but the marginal end of the metallized film (1) is tilted, and the metallicon becomes the metallized electrode. It becomes difficult to enter the electrode side end of the film (50). As a result, the metal thin film (3 (50)) of the metallized film and the metallicon are poorly bonded, and the current resistance decreases. In addition, in the meaning of the metal thin film (3) of a metallized film (50), it represented as a metal thin film (3 (50)).

  On the other hand, FIG. 5 shows a case where Lm1 (20) is larger than Lm2 (21). FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view. In this case, even when the margin side end of the metallized film (1) falls down, the metal thin film (3 (50)) of the metallized film (50) and the metallicon are in a good bonding state. Therefore, Lm1 (20) is preferably larger than Lm2 (21). On the other hand, if Lm1 and Lm2 are too large, the mechanical strength of the capacitor will be reduced and deformation will occur. If it is too small, it will be impossible to efficiently secure a gap between the films as in the conventional method. . Therefore, both Lm1 and Lm2 are preferably 0.05 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 2 mm or less. Lm1 / Lm2 is greater than 1 and preferably 100 or less. Furthermore, Lm1 / Lm2 is more preferably greater than 1 and 20 or less.

  Next, examples showing the effects of tan δ and current resistance of a metallized film capacitor using the metallized film of the present invention will be described. The present invention is not limited to these examples.

  The characteristics and numerical values of the film capacitors obtained in each Example and Comparative Example are defined below including the measurement method and evaluation method.

[Method for evaluating physical properties]
(1) Film thickness
According to JIS C 2151 (1990 edition), the thickness of 10 layers of films was measured with an electronic microphone meter, and the average value obtained by averaging 5 points was divided by the number of metallized films (10) to obtain the metallized film thickness.

(2) Resistance value of metal thin film A metallized film sample having a width of 10 mm and a length of 250 mm was prepared. By measuring the metal film resistance between 100 mm electrodes by the 4-terminal method and multiplying the measured value by (measurement width (= 10 mm) / distance between electrodes (= 100 mm)), the film per 10 mm width and 10 mm distance between electrodes Resistance was calculated. The unit is displayed as Ω / □.

(3) Pitch length and amplitude of corrugated shape at side end portion Magnified by a factor of 50 with a Nikon Corporation projector, and the length of each part is measured with a Nikon digital counter CM-6S.

(4) Margin and shift width Magnify 50 times with Nikon Corporation projector and measure the length of each part with Nikon Digital Counter CM-6S.

(5) Capacitor capacity and tan δ
Using LCR METER AG-4311 manufactured by Ando Electric Co., Ltd., the capacitance of the metallized film capacitor and the tan δ at a frequency of 50 kHz were measured. tan δ is an index indicating the electrical loss of the capacitor. A smaller value indicates a capacitor with less loss. The unit is percent (%). A plurality of capacitors are measured to obtain the average of the capacity and tan δ, which are referred to as the average capacity and the average tan δ, respectively. Further, the measurement position was a position 25 mm above the soldered portion of the lead wire to be soldered on the metallicon.

(6) Current resistance A current of 10 μsec is applied to the metallized film capacitor to be evaluated, and a current value at which a breakdown state occurs is defined as a breakdown current value. The peak current of the applied current is increased from 350A by 50A. Application was performed 10 times for each current value. That is, for example, when the breakdown current value is 450 A, it means that after 300 times of 350 A, 400 A, and 450 A currents are applied, a total of 30 times, and then a breakdown state is reached.

It was evaluated by measuring tan δ at a frequency of 50 kHz of the metallized film capacitor after 10 times of current application for one current value. If the amount of change in tan δ after application was 50% or more, it was determined that the metallized film capacitor had broken down. The amount of change in tan δ is a value shown below.
Tan δ variation (%) = (tan δ after current application−tan δ before current application) × 100 / tan δ before current application

20 capacitors to be evaluated were measured for each of the production conditions. The number of breakdown capacitors at each current value was counted, and a breakdown current value of 650 A or more was judged as a good capacitor. Regarding the variation in current resistance, a current value width obtained by subtracting the minimum breakdown current value from the maximum breakdown current value among the evaluated capacitors was defined as a variation, and a current value width of 150 A or less was determined as a favorable variation.
(7) Comprehensive evaluation Comprehensive evaluation of the capacitor was performed according to the following criteria.
A: The breakdown current value of all capacitors is 650 A or more and the variation is 150 A or less.
○: The breakdown current value of all capacitors is 650 A or more, but the variation is larger than 150 A.
Δ: There is a capacitor having a breakdown current value of 650 A or more.
X: The breakdown current value of all the capacitors is less than 650A.
Next, manufacturing conditions of each sample will be described.

(Example 1)
The dielectric film was a biaxially stretched polypropylene having a thickness of 5.0 μm. First, a mask for forming a margin was formed in the longitudinal direction of the dielectric film in a vacuum deposition machine, and aluminum was deposited as a metal material. For example, a method of applying an oil component is conceivable for the mask, but the method is not limited thereto.

  Next, the deposited film was slit so as to have a margin of 1.5 mm and a width of 20 mm. Here, the slitter apparatus used was equipped with a curved cutter, so that the film cut surface could form a corrugated shape. The obtained metallized film had a corrugated shape at both side edges, and the pitch length of the corrugated shape at the marginal edge was 1.5 mm and the amplitude was 0.5 mm.

  On the other hand, the pitch length of the corrugated shape at the electrode side end was 2.5 mm and the amplitude was 0.5 mm. Here, when the film resistance value of the obtained metallized film was measured, it was 3.5Ω / □. Next, the obtained two metallized films are laminated so that the margins are opposite to each other, wound with a shift width of 0.5 mm, metallized, and soldered to the electrode terminals. Produced.

  Twenty metallized film capacitors were prepared and the capacitance and tan δ were measured. The average capacitance of the 20 capacitors was 0.51 μF, and the average tan δ was 0.135%. When the current resistance of these capacitors was evaluated, good results were obtained. In all samples, the breakdown current value is 650 A or more and the variation is 150 A or less, and the results are shown in Tables 1 and 2.

(Example 2)
Example except that the pitch length of the corrugated shape at the margin side end is 2.5 mm and the amplitude is 0.4 mm, and the pitch length of the corrugated shape at the electrode side end is 1.5 mm and the amplitude is 0.4 mm. A metallized film capacitor similar to 1 was obtained. The obtained 20 metallized film capacitors had an average capacity of 0.49 μF and an average tan δ of 0.14%. When the current resistance was evaluated, all samples had a breakdown current value of 650 A or more and a variation of 150 A or less, which was a good result. The results are shown in Tables 1 and 2.

(Example 3)
Example except that the pitch length of the wave shape at the margin side end is 2.5 mm and the amplitude is 0.7 mm, and the pitch length of the wave shape at the electrode side end is 2.5 mm and the amplitude is 0.25 mm. A metallized film capacitor similar to 1 was obtained. The obtained 20 metallized film capacitors had an average capacity of 0.5 μF and an average tan δ of 0.142%. When the current resistance was evaluated, all samples had a breakdown current value of 650 A or more and a variation of 150 A or less, which was a good result. The results are shown in Tables 1 and 2.

Example 4
Example except that the corrugated pitch length at the margin side end is 2.5 mm and the amplitude is 0.5 mm, and the corrugated pitch length at the electrode end is 2.5 mm and the amplitude is 0.5 mm. A metallized film capacitor similar to 1 was obtained. The obtained 20 metallized film capacitors had an average capacity of 0.5 μF and an average tan δ of 0.146%. When the current resistance evaluation was performed, the variation was 150 A or more, but there were four samples having a breakdown current value of 650 A or more. The results are shown in Tables 1 and 2.

(Comparative Example 1)
A slitter device equipped with a linear cutter was used in the film cutting step, and a metallized film capacitor similar to Example 1 was obtained except that both side ends of the metallized film were straight. The obtained 20 metallized film capacitors had an average capacity of 0.49 μF and an average tan δ of 0.18%. When the current resistance evaluation was performed, the breakdown current value of all the samples was 600 A or less, which was defective. The results are shown in Tables 1 and 2.

(Comparative Example 2)
A slitting device equipped with a linear cutter was used for the margin-side film cutting step, and a metallized film capacitor similar to that of Example 1 was obtained except that the margin-side end was a straight line. The obtained 20 metallized film capacitors had an average capacity of 0.5 μF and an average tan δ of 0.15%. When the current resistance evaluation was performed, the breakdown current value of all the samples was 600 A or less, which was defective. The results are shown in Tables 1 and 2.

Note) The numerical value of the applied current item indicates the number of samples that are destroyed by the applied current.

  The difference between Examples 1 to 4 and Comparative Examples 1 and 2 is whether or not both end portions are cut into corrugated shapes. In the comparison of the value of tan δ, Examples 1 to 4 show smaller values than Comparative Examples 1 and 2, and it can be seen that the capacitors of Examples 1 to 4 using the metallized film of the present invention have less heat loss. Further, in the withstand current characteristics, there are capacitors that are not broken in Examples 1 to 4 until 650 A, whereas Comparative Examples 1 and 2 are all broken by 600 A. Therefore, it can be seen that the characteristics of both the tan δ and the current resistance characteristics are improved by cutting the both end portions into a corrugated shape.

  The difference between the first and second embodiments and the fourth embodiment is whether the pitch length Lp1 at the margin side end portion is different from or equal to the pitch length Lp2 at the electrode side end portion. Both the first and second embodiments and the fourth embodiment are provided with respect to the point that the corrugated cutting process is performed on both end portions.

  Comparing the value of tan δ, Examples 1 and 2 are smaller than Example 4, and Examples 1 and 2 have less loss. Further, regarding the current resistance characteristics, it can be seen that in Example 4, there is a sample that does not break down to 650 A or more, but there is a sample that is broken in a lower current value, and the variation is large. That is, it can be seen that if the corrugated cutting process is applied to both end portions and the pitch length is different, the “variation in current resistance” is reduced.

  The difference between the third embodiment and the fourth embodiment is whether the amplitude of the margin side end portion Lm1 is different from or equal to the amplitude of the electrode side end portion Lm2. In Example 3, since tan δ and current resistance characteristics are the same as those in Examples 1 and 2, the difference in characteristics from Example 4 is the same as in the case of pitch length. That is, even if the pitch length is the same, if the amplitudes are different, it is possible to obtain a capacitor having high current resistance characteristics, a small “variation in current resistance”, and a small tan δ.

  From the above results, the metallized film of the present invention has a corrugated shape cut on both side ends, and more preferably, the margin side end amplitude Lm1 is the electrode side end amplitude Lm2. A larger metallized film. The capacitor of the present invention is a capacitor produced by laminating this metallized film.

The term “cut” or “cut” is used throughout this specification, but is not limited to cutting a film using a slitter device. For example, a hole is formed using a laser beam. It also includes processing methods such as burning out. Further, in the present specification, the description has been given mainly with the “wave shape” as a sine curve, but the present invention is not limited to this, and a triangular wave shape, a trapezoidal shape, a square shape, These bonds are included. Further, a combination of periodic curves other than a sine curve may be used. For example, the shape may be such that the amplitude and pitch length change at a constant period.

It is the schematic diagram and sectional drawing which showed the structure of the metallized film regarding this invention. It is sectional drawing which showed the structure of the metallized film capacitor regarding this invention. It is an enlarged view which shows the lamination | stacking state of the side edge part of the metallized films (1) and (50) regarding this invention. It is an enlarged view which shows the lamination | stacking state of the side edge part of the metallized films (1) and (50) regarding this invention. It is an enlarged view which shows the lamination | stacking state of the side edge part of the metallized films (1) and (50) regarding this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metallized film 2 Dielectric film 3 Metal thin film 4 Margin 50 Metallized film 106 Shift width 110 Metallicon

Claims (6)

A metallized film in which at least one metal thin film is formed on the top surface of a dielectric film,
The metallized film has two opposing side edges cut into a corrugated shape,
The upper surface of one side end is an electrode side end on which the metal thin film is formed,
The upper surface of the other side end is a metallized film that is a margin side end where the metal thin film is not formed. Pitch length (Lp2) of the corrugated shape at the electrode side end,
The metallized film according to claim 1, wherein a pitch length (Lp1) of the corrugated shape at the margin side end portion is different. The pitch length (Lp2) of the corrugated shape at the electrode side end portion and the pitch length (Lp1) of the corrugated shape at the margin side end portion are:
The metallized film according to claim 2, wherein Lp1 / Lp2 is 0.01 or more and 100 or less. The amplitude (Lm2) of the corrugated shape at the electrode side end is:
The metallized film according to any one of claims 1 to 3, wherein the metallized film is smaller than an amplitude (Lm1) of the corrugated shape at the margin side end. The amplitude (Lm2) of the corrugated shape at the electrode side end and the amplitude (Lm1) of the corrugated shape at the margin side end are:
The metallized film according to claim 4, wherein Lm1 / Lm2 is greater than 1 and 100 or less. A capacitor having a structure in which the metallized film according to claim 1 is laminated.