Method for manufacturing a metallized film, method for manufacturing a film capacitor, and manufacturing apparatus for a metallized film

Abstract

To provide a manufacturing method of metalized film capable of manufacturing a metalized film that is thinner and has a higher degree of orientation than the conventional one.SOLUTION: The manufacturing method of a metalized film 1 includes: a stretching step of stretching a dielectric film 2 while transporting the same in a transport direction; and a vapor deposition step of depositing a metal 3 over the stretched dielectric film 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to a method for manufacturing a metallized film, a method for manufacturing a film capacitor, and an apparatus for manufacturing a metallized film. More specifically, the present disclosure relates to a method for manufacturing a metallized film in which a metal is vapor-deposited on a dielectric film, a method for manufacturing a film capacitor using the metallized film, and an apparatus for manufacturing a metallized film.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a metal magnetic thin film type magnetic recording medium. In this method for manufacturing a metal magnetic thin film type magnetic recording medium, when vapor-depositing a metal magnetic thin film on a non-magnetic support, the non-magnetic support is stretched in the width direction within the range of its elastic deformation, and both side ends in the width direction of the non-magnetic support are pressed against a cooling can, and the vapor-deposition is performed while maintaining the state of being stretched in the width direction within the range of the elastic deformation of the non-magnetic support.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as in Patent Document 1, simply stretching the non-magnetic support in the width direction within the range of its elastic deformation easily releases the residual stress, so the non-magnetic support easily returns to its original state before stretching. Therefore, it is difficult to reduce the thickness of the non-magnetic support or change its structure.

[0005] An object of the present disclosure is to provide a method for manufacturing a metallized film capable of manufacturing a metallized film that is thinner and has a higher degree of orientation than conventional ones, a method for manufacturing a film capacitor having high withstand voltage and capable of achieving miniaturization, and an apparatus for manufacturing a metallized film.

Means for Solving the Problem

[0006] The method for manufacturing a metallized film according to one aspect of the present disclosure includes a stretching step of stretching a dielectric film in the transport direction while transporting the dielectric film, and a vapor deposition step of vapor depositing a metal on the stretched dielectric film.

[0007] The method for manufacturing a film capacitor according to one aspect of the present disclosure includes an element forming step of winding or laminating the metallized film manufactured using the method for manufacturing the metallized film to form a main body portion, forming a pair of electrodes on the main body portion, and connecting a bus bar to the pair of electrodes to form a capacitor element, and a sealing step of sealing the capacitor element with resin.

[0008] The manufacturing apparatus for a metallized film according to one aspect of the present disclosure includes a feeding unit that feeds out a dielectric film, a first stretching roll, and a second stretching roll having a peripheral speed higher than that of the first stretching roll, and a stretching processing unit that stretches the dielectric film conveyed from the feeding unit in the transport direction by bridging the dielectric film over the first stretching roll and the second stretching roll, a vapor deposition processing unit that vapor deposits a metal on the dielectric film stretched by the stretching processing unit to form a metallized film, and a winding unit that winds up the metallized film.

Advantages of the Invention

[0009] According to the present disclosure, it is possible to manufacture a metallized film that is thinner and has a higher degree of orientation than conventional ones.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] 1. Summary The manufacturing method of the metallized film 1 according to this embodiment includes a stretching step and a vapor deposition step. In the stretching step, the dielectric film 2 is stretched in the conveying direction while being conveyed. Thereby, the thickness of the dielectric film 2 can be reduced. Also, the structure (internal structure, etc.) of the dielectric film 2 can be changed. Specifically, when the dielectric film 2 has a crystalline region and an amorphous region, the molecular chains in the crystalline region and the amorphous region are oriented in the conveying direction. That is, after stretching compared to before stretching, the degree of orientation of the crystalline region and the amorphous region of the dielectric film 2 increases. And in the vapor deposition step, the metal 3 is vapor-deposited on the dielectric film 2 stretched as described above.

[0012] In this embodiment, by making the conveying direction of the dielectric film 2 coincide with the stretching direction of the dielectric film 2, even after the stretching step, it is possible to make it difficult for the dielectric film 2 to return to its original state before stretching. Conversely, if the conveying direction of the dielectric film 2 and the stretching direction of the dielectric film 2 are orthogonal as in Patent Document 1, it is considered that after the stretching step, the dielectric film 2 easily returns to its original state before stretching.

[0013] Therefore, according to this embodiment, it is possible to manufacture a metallized film that is thinner and has a higher degree of orientation than before.

[0014] 2. Details Hereinafter, the manufacturing method of the metallized film 1, the manufacturing method of the film capacitor 10, and the manufacturing apparatus 100 of the metallized film 1 according to this embodiment will be described with reference to the drawings. Each figure is a schematic diagram, and the size of each component in the figure does not necessarily reflect the actual dimensions. Note that since the manufacturing apparatus 100 of the metallized film 1 is suitable for directly implementing the manufacturing method of the metallized film 1, first, the manufacturing apparatus 100 of the metallized film 1 will be described, and then the manufacturing method of the metallized film 1 and the manufacturing method of the film capacitor 10 will be described in order.

[0015] (1) Manufacturing Apparatus of Metallized Film <Overall Structure> As shown in FIG. 1, the manufacturing apparatus 100 for the metallized film 1 according to the present embodiment includes a feeding unit 5, a stretching unit 6, a heat treatment unit 91, a cooling treatment unit 93, a masking treatment unit 97, a vapor deposition unit 7, and a winding unit 8.

[0016] The dielectric film 2, which is the material of the metallized film 1, is conveyed from the feeding unit 5, passes through the stretching unit 6, the heat treatment unit 91, the cooling treatment unit 93, and the masking treatment unit 97, is processed into the metallized film 1 in the vapor deposition unit 7, and the metallized film 1 is wound up by the winding unit 8. In this way, the feeding unit 5 is arranged on the most upstream side in the conveying direction of the dielectric film 2, and the winding unit 8 is arranged on the most downstream side.

[0017] The manufacturing apparatus 100 for the metallized film 1 further includes a first housing chamber 41, a second housing chamber 42, and a vacuum pump 45. The first housing chamber 41 and the second housing chamber 42 are partitioned by a partition plate 43. The partition plate 43 has an opening 44. The first housing chamber 41 and the second housing chamber 42 communicate with each other through the opening 44.

[0018] The first housing chamber 41 houses the feeding unit 5, the stretching unit 6, the heat treatment unit 91, the cooling treatment unit 93, the masking treatment unit 97, and the winding unit 8. Note that the first housing chamber 41 also houses a part of the vapor deposition unit 7 (a part of the can roll 70).

[0019] The second housing chamber 42 houses the vapor deposition unit 7.

[0020] The vacuum pump 45 is connected to the second housing chamber 42. By operating the vacuum pump 45, the inside of the second housing chamber 42 can be evacuated. Since the first housing chamber 41 communicates with the second housing chamber 42 through the opening 44, the inside of the first housing chamber 41 can also be evacuated. Since the vacuum pump 45 is directly connected to the second housing chamber 42, it is easier to make the second housing chamber 42 have a higher vacuum than the first housing chamber 41. Note that "vacuum" means a state of a space filled with a gas at a pressure lower than the normal atmospheric pressure (101.3 kPa at 20°C).

[0021] Thus, the feeding section 5, stretching section 6, heat treatment section 91, cooling treatment section 93, masking treatment section 97, vapor deposition section 7, and winding section 8 are arranged under vacuum. Hereinafter, the feeding section 5, stretching section 6, heat treatment section 91, cooling treatment section 93, masking treatment section 97, vapor deposition section 7, and winding section 8 will be described in order.

[0022] <Feeding section> The feeding section 5 is a portion for feeding the dielectric film 2. Specifically, the feeding section 5 has a feeding roll 50. The feeding roll 50 is a roll around which the long dielectric film 2 is wound in a cylindrical shape. The feeding roll 50 is rotatably arranged.

[0023] The material of the dielectric film 2 is not particularly limited, and examples thereof include crystalline plastics. Examples of the crystalline plastic include polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and polyethylene naphthalate (PEN).

[0024] The thickness of the dielectric film 2 is not particularly limited, and for example, it is 1.0 μm or more and 10.0 μm or less.

[0025] <Stretching section> The stretching section 6 is a portion for stretching the dielectric film 2 conveyed from the feeding section 5 in the conveying direction. The stretching section 6 is arranged on the downstream side in the conveying direction from the feeding section 5. The stretching section 6 has a first stretching roll 61 and a second stretching roll 62.

[0026] The first stretching roll 61 is arranged parallel to and rotatably with respect to the feeding roll 50. The dielectric film 2 conveyed from the feeding section 5 is first bridged over the first stretching roll 61.

[0027] The second stretching roll 62 is arranged on the downstream side in the conveyance direction from the first stretching roll 61. Further, the second stretching roll 62 is arranged in parallel and rotatably with respect to the first stretching roll 61. The dielectric film 2 conveyed from the first stretching roll 61 is then bridged over to the second stretching roll 62.

[0028] Here, the peripheral speed of the second stretching roll 62 is faster than the peripheral speed of the first stretching roll 61. That is, the peripheral speed of the upstream first stretching roll 61 is slow, and the peripheral speed of the downstream second stretching roll 62 is fast. Thus, due to the difference in the peripheral speeds of the first stretching roll 61 and the second stretching roll 62, when the dielectric film 2 conveyed from the pay-out section 5 is bridged over the first stretching roll 61 and the second stretching roll 62, it is stretched in the conveyance direction. The section between the first stretching roll 61 and the second stretching roll 62 is the stretching section. That is, the dielectric film 2 is stretched in the stretching section.

[0029] <Heat treatment section> The heat treatment section 91 is a part that performs a process of heating the dielectric film 2 stretched by the stretching process section 6. The heat treatment section 91 is arranged so as to face the dielectric film 2 existing in the stretching section. In the present embodiment, the heat treatment section 91 has an infrared heater. The dielectric film 2 is heated while being stretched by irradiating the infrared rays from the infrared heater to the dielectric film 2 in the stretching section.

[0030] The infrared rays preferably contain at least either near-infrared rays (wavelength: 780 nm or more and 2.5 μm or less) and mid-infrared rays (wavelength: 2.5 μm or more and 4 μm or less). Thereby, while reducing temperature unevenness, the dielectric film 2 can be heated uniformly. Further, when the dielectric film 2 contains volatile components (such as moisture and additives described later), it becomes easier to evaporate and remove the volatile components.

[0031] <Cooling treatment section> The cooling treatment unit 93 is a part that performs the process of cooling the heated dielectric film 2. The cooling treatment unit 93 is arranged on the downstream side in the conveyance direction from the stretching treatment unit 6 and the heating treatment unit 91.

[0032] The cooling treatment unit 93 has at least one or more (three in this embodiment) cooling rolls 93a, 93b, 93c. Further, the cooling rolls 93a, 93b, 93c are arranged parallel and rotatably to the first stretching roll 61 and the second stretching roll 62. The dielectric film 2 that is stretched and heated in the stretching treatment unit 6 is cooled by being conveyed while contacting the outer peripheral surfaces of the cooling rolls 93a, 93b, 93c.

[0033] Note that the second stretching roll 62 may have a cooling function. In this case, the second stretching roll 62 can cool the dielectric film 2 to such an extent that the heated dielectric film 2 does not adhere to the second stretching roll 62.

[0034] <Masking treatment unit> The masking treatment unit 97 is a part that performs the process of masking the portion (non-vapor deposition portion) on one surface (single surface) of the dielectric film 2 where the metal 3 is not vapor-deposited. Masking can be performed by applying oil. The masked portions become the non-vapor deposition portions 20a, 20b in the metallized film 1 (see FIG. 2A). In this embodiment, oil is applied along the longitudinal direction L at one end portion in the short-side direction (width direction) S of the dielectric film 2.

[0035] The masking treatment unit 97 is arranged on the downstream side in the conveyance direction from the cooling treatment unit 93. In the masking treatment unit 97, oil can be applied to the dielectric film 2 by flexographic printing. That is, the masking treatment unit 97 has a printing roll 94 and a backup roll 95. The printing roll 94 and the backup roll 95 are arranged parallel and rotatably to the cooling rolls 93a, 93b, 93c.

[0036] The printing roll 94 is a roll for applying oil to the non-vapor-deposited portion of one surface of the dielectric film 2.

[0037] The backup roll 95 is disposed on the other surface side of the dielectric film 2. The backup roll 95 is a roll for pressing the dielectric film 2 against the printing roll 94. In the following, unless otherwise specified, the "other surface" means the surface opposite to the one surface.

[0038] <Vapor Deposition Processing Unit> The vapor deposition processing unit 7 is a portion that performs a process of vapor-depositing the metal 3 on the dielectric film 2 stretched by the stretching processing unit 6. Thereby, the metallized film 1 is formed.

[0039] The vapor deposition processing unit 7 is disposed on the downstream side in the conveyance direction from the masking processing unit 97. The vapor deposition processing unit 7 includes an evaporation source 30, a crucible 71, and a can roll 70.

[0040] The evaporation source 30 contains the metal 3 to be vapor-deposited on the dielectric film 2. The metal 3 is not particularly limited, and examples thereof include aluminum and zinc.

[0041] The crucible 71 is a heat-resistant container for housing the evaporation source 30 and heating the evaporation source 30 to evaporate the metal 3. The heating method of the evaporation source 30 is not particularly limited, and examples thereof include resistance heating, electron beam heating, arc discharge heating, high-frequency induction heating, and laser heating.

[0042] The can roll 70 is a roll for cooling the dielectric film 2 while conveying the dielectric film 2 on which the metal 3 is vapor-deposited. By the can roll 70, the heat load on the dielectric film 2 due to vapor deposition can be reduced, and the occurrence of wrinkles and tears in the dielectric film 2 can be suppressed. The temperature of the can roll 70 is not particularly limited, and for example, it is -20°C or higher and 0°C or lower.

[0043] The can roll 70 is rotatably disposed at the opening 44 of the partition plate 43. The rotation axis of the can roll 70 is parallel to the partition plate 43. A part of the can roll 70 is disposed in the first storage chamber 41, and the remaining part of the can roll 70 is disposed in the second storage chamber 42.

[0044] The dielectric film 2 is conveyed while being in close contact with the outer peripheral surface of the can roll 70. Metal 3 is vapor-deposited on one surface of the dielectric film 2 (the surface not in contact with the outer peripheral surface of the can roll 70). However, metal 3 is not vapor-deposited on the portion masked by oil. On the other hand, metal 3 is not vapor-deposited on the other surface of the dielectric film 2 (the surface in close contact with the outer peripheral surface of the can roll 70).

[0045] <Take-up section> The take-up section 8 is a portion for winding up the metallized film 1. The take-up section 8 is disposed on the downstream side in the conveyance direction from the vapor deposition processing section 7. Specifically, the take-up section 8 has a take-up roll 80. The take-up roll 80 is rotatably disposed.

[0046] <Others> The manufacturing apparatus 100 for the metallized film 1 may further include at least one or more (two in this embodiment) preheating rolls 92 (92a, 92b). In this embodiment, the preheating roll 92 is disposed between the pay-out section 5 and the stretching processing section 6. In particular, the preheating roll 92 is disposed immediately before the stretching processing section 6. The preheating roll 92 is a roll for heating the dielectric film 2 before stretching. The preheating roll 92 is disposed parallel and rotatably to the first stretching roll 61 and the second stretching roll 62.

[0047] Also, the manufacturing apparatus 100 for the metallized film 1 may further include at least one or more (four in this embodiment) guide rolls 96 (96a, 96b, 96c, 96d). The guide roll 96 is a roll for changing the conveyance direction of the dielectric film 2 or the metallized film 1. The guide roll 96 is disposed parallel and rotatably to other rolls (such as the pay-out roll 50). The location where the guide roll 96 is disposed is not particularly limited.

[0048] (2) Method for manufacturing a metallized film Next, a method for manufacturing the metallized film 1 according to the present embodiment will be described. The method for manufacturing the metallized film 1 can be carried out using the above-described manufacturing apparatus 100 for the metallized film 1.

[0049] The method for manufacturing the metallized film 1 according to the present embodiment includes a stretching step, a cooling step, a masking step, a vapor deposition step, and a winding step. The stretching step, the cooling step, and the vapor deposition step are carried out under vacuum. Thereby, when the dielectric film 2 contains volatile components, it becomes easier to evaporate and remove the volatile components. Examples of the volatile components include moisture and additives. These volatile components are components that can inhibit the vapor deposition of the metal 3 on the dielectric film 2. Further, by carrying out the vapor deposition step under vacuum, it is possible to suppress the metal 3 from colliding with the gas molecules in the second storage chamber 42 before reaching the dielectric film 2. Furthermore, the evaporation temperature of the evaporation source 30 can be lowered to facilitate vapor deposition.

[0050] <Stretching step> In the stretching process, the dielectric film 2 is stretched in the conveying direction while being conveyed. The dielectric film 2 is conveyed from the pay-out section 5 to the stretching processing section 6. Then, since the dielectric film 2 is spanned from the first stretching roll 61 to the second stretching roll 62, it is conveyed from the first stretching roll 61 to the second stretching roll 62. At this time, since the peripheral speed of the second stretching roll 62 is faster than the peripheral speed of the first stretching roll 61, the dielectric film 2 is stretched in the conveying direction. Thereby, the thickness of the dielectric film 2 can be reduced. Further, when the dielectric film 2 has a crystalline region and an amorphous region, the molecular chains in the crystalline region and the amorphous region are oriented in the conveying direction. That is, the degree of orientation of the crystalline region and the amorphous region in the dielectric film 2 increases after stretching compared to before stretching. In this way, by increasing the degree of orientation of the crystalline region and the amorphous region in the plane perpendicular to the thickness direction of the dielectric film 2, breakdown is less likely to occur when a voltage is applied in the thickness direction of the dielectric film 2. That is, when the stretched dielectric film 2 and the non-stretched dielectric film 2 are compared with the same thickness, the former stretched dielectric film 2 can reduce the leakage current flowing in the thickness direction of the dielectric film 2.

[0051] Preferably, in the stretching process, the dielectric film 2 is plastically deformed. That is, by adjusting the difference in peripheral speed between the first stretching roll 61 and the second stretching roll 62, a force exceeding the yield point is applied to the dielectric film 2. In this way, when the dielectric film 2 is plastically deformed instead of elastically deformed, it is possible to prevent the dielectric film 2 from returning to its original shape even after passing through the stretching processing section 6. That is, the dielectric film 2 can continue to maintain a state in which its thickness is reduced and its structure is changed.

[0052] Furthermore, in the present embodiment, the dielectric film 2 is heated in the stretching step. That is, the dielectric film 2 in the stretching section is heated by the heat treatment unit 91. The heating temperature at this time is not particularly limited as long as it exceeds the glass transition temperature (Tg) of the dielectric film 2. This makes it easier to stretch the dielectric film 2. Further, when the dielectric film 2 contains volatile components, the volatile components are evaporated and it becomes easier to further remove them. The volatile components may be present in a larger amount in the amorphous region than in the crystal region.

[0053] Preferably, in the stretching step, the dielectric film 2 is heated to a temperature equal to or higher than the crystallization temperature (Tc). This makes it possible to prepare for crystallizing the dielectric film 2 in the oriented state.

[0054] Here, the "crystallization temperature (Tc)" is the temperature at which the dielectric film 2 starts to crystallize. As an example of the measurement of the crystallization temperature (Tc), using a DSC (differential scanning calorimeter), first, the dielectric film 2 is heated to a temperature 30°C higher than the end temperature of the melting peak, held at this temperature for 10 minutes, and then cooled at a cooling rate of 5°C / min or 10°C / min to a temperature approximately 50°C lower than the end of the crystallization peak to draw a DSC curve. From the obtained DSC curve, the crystallization peak temperature (Tpc) is obtained. Generally, the crystallization peak temperature (Tpc) is regarded as the crystallization temperature (Tc). As a specific example of the crystallization temperature (Tc), when the dielectric film 2 is a polypropylene (PP) film, the crystallization temperature (Tc) is about 120°C.

[0055] The upper limit value of the heating temperature when heating the dielectric film 2 in the stretching step is not particularly limited, but for example, it is the melting point or softening point of the dielectric film 2. As a specific example, when the dielectric film 2 is a polypropylene (PP) film, the upper limit value of the heating temperature is about 170°C or higher and 190°C or lower.

[0056] <Cooling step> In the cooling process, the stretched dielectric film 2 is cooled between the stretching process and the vapor deposition process. In the present embodiment, the dielectric film 2 heated while being stretched is cooled. As a result, the molecular chains in the dielectric film 2 are easily crystallized in an oriented state. Thus, the crystallization of the molecular chains in the dielectric film 2 in an oriented state is sometimes referred to as "oriented crystallization" hereinafter.

[0057] The cooling rate is not particularly limited, but for example, it is 0.01 °C / min or more and 10 °C / min or less.

[0058] Preferably, in the cooling process, the dielectric film 2 is cooled to a temperature lower than the crystallization temperature (Tc). Thereby, the oriented crystallization of the dielectric film 2 can be further promoted. That is, the crystallinity of the dielectric film 2 in the oriented state can be increased. The crystallinity is the fraction of the crystal region with respect to the whole of the crystal region and the amorphous region. Thus, the crystal region in the dielectric film 2 in the oriented state can increase compared to the amorphous region. Since leakage current hardly flows in the crystal region compared to the amorphous region, when the crystallinity of the dielectric film 2 in the oriented state increases, breakdown is less likely to occur when a voltage is applied in the thickness direction of the dielectric film 2. Also, as the amorphous region decreases compared to the crystal region, volatile components are less likely to remain in the dielectric film 2.

[0059] The lower limit value of the cooling temperature when cooling the dielectric film 2 is not particularly limited, but for example, it is the glass transition temperature (Tg) of the dielectric film 2. As a specific example, when the dielectric film 2 is a polypropylene (PP) film, the lower limit value of the cooling temperature is about -20 °C or more and 0 °C or less.

[0060] <Masking process> In the masking process, a portion (non-vapor deposition portion) where the metal 3 is not vapor deposited on one surface of the oriented and crystallized dielectric film 2 is masked. In the present embodiment, oil is applied along the longitudinal direction L at one end of the short side direction S of the dielectric film 2.

[0061] <Evaporation process> In the evaporation process, metal 3 is evaporated onto the stretched dielectric film 2. In this embodiment, metal 3 is evaporated onto the orientation-crystallized dielectric film 2. Thereby, the metallized film 1 is formed.

[0062] Here, if the volatile components remaining in the dielectric film 2 are removed as much as possible before the evaporation process, the evaporation density of the metal 3 can be increased.

[0063] In this embodiment, on one surface of the orientation-crystallized dielectric film 2, metal 3 is evaporated except for one end portion on one side in the short side direction S of the dielectric film 2. Since oil is applied to one end portion on one side in the short side direction S of the dielectric film 2, metal 3 is not evaporated.

[0064] <Winding process> In the winding process, the metallized film 1 is wound. The metallized film 1 is a long film. One surface of the metallized film 1 has a vapor deposition portion 3a and a non-vapor deposition portion 20a (see FIG. 2A). The vapor deposition portion 3a is a portion where metal 3 is vapor-deposited. The thickness of the vapor deposition portion 3a is not particularly limited, but is, for example, 5 nm or more and 100 nm or less. The non-vapor deposition portion 20a is a portion where metal 3 is not vapor-deposited. That is, it is a portion where the dielectric film 2 is exposed. On the other hand, since the other surface of the metallized film 1 was in close contact with the outer peripheral surface of the can roll 70, metal 3 was not vapor-deposited and the dielectric film 2 was exposed.

[0065] Also, in this embodiment, there is no winding process of winding the stretched dielectric film 2 between the stretching process and the vapor deposition process. Since the thickness of the stretched dielectric film 2 is thin, if it is wound up once, wrinkles and tears may occur. In this embodiment, the dielectric film 2 after the stretching process is conveyed to the vapor deposition process without being wound up, so that the occurrence of wrinkles and tears in the stretched dielectric film 2 can be suppressed. The metallized film 1 after the vapor deposition process has metal 3 vapor-deposited thereon, so its strength is improved compared to the simply stretched dielectric film 2. Therefore, even if the metallized film 1 is wound up, the occurrence of wrinkles and tears can be suppressed.

[0066] <Function and effect> As described above, the method for manufacturing the metallized film 1 according to this embodiment includes a stretching process and a vapor deposition process.

[0067] In the stretching process, the dielectric film 2 is stretched in the conveyance direction while being conveyed. Thereby, the thickness of the dielectric film 2 can be made thinner. For example, when the thickness of the dielectric film 2 before stretching is 2.3 μm, the thickness of the dielectric film 2 after stretching becomes 2.1 μm, and the thickness can be reduced by about 10%.

[0068] Also, the structure (internal structure, etc.) of the dielectric film 2 can be changed. That is, when the dielectric film 2 is stretched, the molecular chains in the dielectric film 2 are oriented in the stretching direction.

[0069] And in the vapor deposition process, metal 3 is vapor-deposited on the stretched dielectric film 2.

[0070] As described above, in this embodiment, by making the conveyance direction of the dielectric film 2 and the stretching direction of the dielectric film 2 coincide, it is possible to make it difficult for the dielectric film 2 to return to its original state before stretching even after the stretching process.

[0071] Therefore, according to the present embodiment, a metallized film that is thinner and has a higher degree of orientation than conventional ones can be manufactured.

[0072] (3) Method for manufacturing a film capacitor Next, a method for manufacturing the film capacitor 10 according to the present embodiment will be described with reference to the drawings. Although the X-axis, Y-axis, and Z-axis that are mutually orthogonal are illustrated in the drawings, these axes are only illustrated for convenience of explanation and do not limit the direction of the film capacitor 10 and have no physical entity. Also, hereinafter, "side view" means viewing along the Y-axis direction.

[0073] The method for manufacturing the film capacitor 10 according to the present embodiment includes an element formation step and a sealing step. Hereinafter, the element formation step and the sealing step will be described in order.

[0074] <Element formation step> In the element formation step, a capacitor element 16 is formed (see FIG. 2B). The capacitor element 16 is of a wound type or a stacked type. In the present embodiment, a wound type capacitor element 16 is formed. Hereinafter, the case of forming a wound type capacitor element 16 will be described.

[0075] First, as shown in FIG. 2A, the metallized film 1 manufactured by using the above-described method for manufacturing the metallized film 1 is wound to form the main body portion 13. Specifically, two metallized films 1 (the first metallized film 11 and the second metallized film 12) are prepared, and these metallized films 1 are stacked and wound. Note that the lengths of the two metallized films 1 in the short side direction S are equal.

[0076] That is, the first metallized film 11 has a vapor-deposited portion 3a and a non-vapor-deposited portion 20a. The vapor-deposited portion 3a and the non-vapor-deposited portion 20a are present on one surface of the first dielectric film 2a. The vapor-deposited portion 3a is present in a portion excluding one end portion (right end portion) in the short-side direction S of the first dielectric film 2a. The non-vapor-deposited portion 20a is present at one end portion (right end portion) in the short-side direction S of the first dielectric film 2a. There is no vapor-deposited portion 3a on the other surface of the first dielectric film 2a.

[0077] On the other hand, the second metallized film 12 has a vapor-deposited portion 3b and a non-vapor-deposited portion 20b. The vapor-deposited portion 3b and the non-vapor-deposited portion 20b are present on one surface of the second dielectric film 2b. The vapor-deposited portion 3b is present in a portion excluding the other end portion (left end portion) in the short-side direction S of the second dielectric film 2b. The non-vapor-deposited portion 20b is present at the other end portion (left end portion) in the short-side direction S of the second dielectric film 2b. There is no vapor-deposited portion 3b on the other surface of the second dielectric film 2b.

[0078] Then, the other surface of the first metallized film 11 and one surface of the second metallized film 12 are opposed and overlapped, and in this state, the two metallized films 1 are wound in the longitudinal direction L to obtain a cylindrical wound body 13a (see FIG. 2A). By pressurizing the wound body 13a in the Z-axis direction, a flat wound body 13b is obtained (see FIG. 2B). The flat wound body 13b has a substantially rectangular shape in side view and has a three-dimensional shape extending in the Y-axis direction. In the present embodiment, the flat wound body 13b is used as the main body portion 13.

[0079] Next, a pair of electrodes 14 are formed on the main body portion 13. Specifically, the electrodes 14 are formed at both ends of the main body portion 13 in the Y-axis direction. The electrodes 14 can be formed by a metal spraying method.

[0080] Next, a bus bar 15 is connected to the pair of electrodes 14 to form a capacitor element 16. The bus bar 15 is a conductive member extending in the Z-axis direction. The pair of bus bars 15 are arranged side by side in the Y-axis direction and parallel to the Z-axis direction. The material of the bus bar 15 is not particularly limited, and examples thereof include copper and the like.

[0081] In the case of forming the multilayer capacitor element 16, the metallized films 1 are laminated to form the main body portion 13. For example, the first metallized film 11 and the second metallized film 12 are cut into a predetermined size, and these are alternately laminated in the thickness direction (Z-axis direction) to form the main body portion 13. The steps after forming the main body portion 13 are the same as those in the case of the wound capacitor element 16.

[0082] <Sealing step> In the sealing step, as shown in FIG. 2C, the capacitor element 16 is sealed with the resin 17. Thereby, the film capacitor 10 can be manufactured.

[0083] The resin 17 is not particularly limited, and examples thereof include thermosetting resins such as epoxy resins. A sealing portion 18 is formed of a cured product of the resin 17. The sealing portion 18 seals the capacitor element 16. That is, the capacitor element 16 is buried in the sealing portion 18. In the present embodiment, the sealing portion 18 has a rectangular parallelepiped shape. In the Z-axis direction, a pair of bus bars 15 project from the surface facing the +Z side of the sealing portion 18. By applying a voltage between the pair of bus bars 15, the film capacitor 10 can be charged.

[0084] <Function and effect> According to the present embodiment, the film capacitor 10 having high withstand voltage can be easily manufactured. That is, in the above-described metallized film 1, the degree of orientation of the crystal region and the amorphous region increases in the plane perpendicular to the thickness direction of the dielectric film 2, so that dielectric breakdown is less likely to occur when a voltage is applied in the thickness direction of the dielectric film 2. Since the film capacitor 10 is manufactured using such a metallized film 1, the withstand voltage of the film capacitor 10 can be increased.

[0085] According to this embodiment, it is also possible to easily manufacture the film capacitor 10 that can achieve miniaturization. The above-described metallized film 1 is thinner than before. Since the film capacitor 10 is manufactured using such a metallized film 1, miniaturization of the film capacitor 10 can be achieved as compared with a conventional product of the same capacitance.

[0086] Furthermore, according to this embodiment, it is also possible to easily manufacture the film capacitor 10 that can achieve high capacitance. As described above, since the metallized film 1 is thinner than before, high capacitance of the film capacitor 10 can be achieved as compared with a conventional product of the same dimensions.

[0087] 3. Modification Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and can be appropriately changed without departing from the technical idea of the present disclosure.

[0088] In the above embodiment, the heat treatment unit 91 has an infrared heater, but it may have a heating roll.

[0089] In the above embodiment, the manufacturing apparatus 100 of the metallized film 1 includes a preheating roll 92, but it may not include the preheating roll 92.

[0090] In the above embodiment, one end portion in the short side direction S of the dielectric film 2 is masked, but the masked portion is not particularly limited.

Explanation of Reference Numerals

[0091] 1 Metallized film 10 Film capacitor 13 Body portion 14 Electrode 15 Bus bar 16 Capacitor element 17 Resin 2 Dielectric film 3 Metal 5 Pay-out portion 6 Stretching treatment unit 61 First stretching roll 62 Second stretching roll 7 Vapor deposition treatment section 8 Take-up section 91 Heat treatment section 93 Cooling treatment section 100 Production apparatus for metallized film

Claims

1. A stretching step of stretching the dielectric film in the conveying direction while conveying the dielectric film, and a vapor deposition step of vapor-depositing a metal on the stretched dielectric film, and the stretching step and the vapor deposition step are carried out under vacuum, A method for manufacturing a metallized film.

2. In the stretching step, the dielectric film is plastically deformed, The method for manufacturing a metallized film according to claim 1.

3. In the stretching step, the dielectric film is bridged to a second stretching roll that is arranged downstream of the first stretching roll in the conveying direction and has a peripheral speed higher than that of the first stretching roll, The method for manufacturing a metallized film according to claim 1 or 2.

4. In the stretching step, the dielectric film is heated, The method for manufacturing a metallized film according to any one of claims 1 to 3.

5. In the stretching step, the dielectric film is heated to a temperature equal to or higher than the crystallization temperature, The method for manufacturing a metallized film according to claim 4.

6. Between the stretching step and the vapor deposition step, a cooling step of cooling the stretched dielectric film is further included, The method for manufacturing a metallized film according to claim 4 or 5.

7. In the cooling step, the dielectric film is cooled to a temperature lower than the crystallization temperature, The method for manufacturing a metallized film according to claim 6.

8. The cooling step is carried out under the vacuum, The method for manufacturing a metallized film according to claim 6 or 7.

9. The metallized film manufactured by using the method for manufacturing a metallized film according to any one of claims 1 to 8 is wound or laminated to form a main body portion, a pair of electrodes are formed on the main body portion, and a bus bar is connected to the pair of electrodes to form a capacitor element, and an element forming step; A sealing step of sealing the capacitor element with resin, and A method for manufacturing a film capacitor.

10. A feeding section for feeding a dielectric film, A stretching processing section for stretching the dielectric film conveyed from the feeding section in the conveying direction, A vapor deposition processing section for vapor-depositing a metal on the dielectric film stretched by the stretching processing section to form a metallized film, A winding section for winding the metallized film, and the stretching processing section and the vapor deposition processing section are arranged under vacuum, A manufacturing apparatus for a metallized film.

11. The stretching processing section is It has a first stretching roll and a second stretching roll having a peripheral speed higher than that of the first stretching roll, The dielectric film is stretched by being bridged over the first stretching roll and the second stretching roll, The manufacturing apparatus for a metallized film according to claim 10.

12. The manufacturing apparatus for a metallized film further includes a heat treatment unit that heats the dielectric film stretched by the stretching unit, The manufacturing apparatus for a metallized film according to claim 10.

13. The manufacturing apparatus for a metallized film further includes a cooling treatment unit that cools the heated dielectric film, The manufacturing apparatus for a metallized film according to claim 12.

14. The heat treatment unit and the cooling treatment unit are arranged under the vacuum, The manufacturing apparatus for a metallized film according to claim 13.

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