Method for manufacturing metal fine wire pattern sheet, method for manufacturing band-pass filter sheet manufactured using same, metal fine wire pattern sheet, and band-pass filter sheet using same

Abstract

A method for manufacturing a metal fine wire pattern sheet of the present application comprises: a first step of forming a photoresist layer on a conductive surface of a master; a second step of removing a part of the photoresist layer formed in the first step by a photolithography method, thereby forming a resist body for fine wire pattern formation; a third step of electrodepositing a metal by electroforming on the conductive surface of the master on which the resist body for fine wire pattern formation has been formed in the second step, thereby forming a metal fine wire pattern layer; and a fourth step of transferring the metal fine wire pattern layer formed in the third step from the master onto a base material layer to dispose the metal fine wire pattern layer on a surface of the base material layer, thereby forming the metal fine wire pattern sheet.

Description

Method for manufacturing a metal fine wire pattern sheet, method for manufacturing a bandpass filter sheet manufactured using the same, metal fine wire pattern sheet, and bandpass filter sheet using the same 【0001】 This application relates to a method for manufacturing a metal fine wire pattern sheet, a method for manufacturing a bandpass filter sheet manufactured using the same, a metal fine wire pattern sheet, and a bandpass filter sheet using the same. 【0002】 With the development of wireless communication technologies represented by mobile phones, various devices and sensors are being wirelessly connected to networks. Also, in the medical field, from the perspective of infection prevention, equipment is becoming cordless, and medical devices are starting to be wirelessly connected. These communications require high-speed large-capacity at relatively short distances and use high frequencies. With the increase in devices using such high frequencies, the risk of malfunctions due to electromagnetic noise generated by the devices and interference with the used electromagnetic waves, etc., causing problems in electronic devices and communications is increasing. Furthermore, in recent years, the installation of millimeter-wave radars for the purpose of preventing automobile collision accidents has also started. Malfunctions in devices in these medical and automotive fields affect human lives, so there must be no malfunction. Therefore, there is an increasing need to apply electromagnetic noise suppression sheets, which are measures for preventing malfunctions caused by electromagnetic noise of devices and the interference caused thereby, so-called EMC (Electromagnetic Compatibility), to circuit elements and transmission lines that transmit and receive electromagnetic waves from the millimeter-wave band to the sub-millimeter-wave band. 【0003】 By providing electromagnetic noise suppression sheets to society, it is possible to contribute to the achievement of three of the 17 goals of the Sustainable Development Goals (SDGs) established by the United Nations: Goal 3 (Ensure healthy lives and promote well-being for all people of all ages), Goal 9 (Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation), and Goal 12 (Ensure sustainable consumption and production patterns). 【0004】Meanwhile, as the field of technology related to information transmission using radio waves is expected to develop further in the future, there is a need for radio wave absorbing sheets that absorb unwanted radio waves of a specific frequency while transmitting necessary radio waves of a specific frequency, for example, in antenna transceivers that receive and transmit radio waves from the air. 【0005】 Patent Document 1 proposes an electromagnetic interference type electromagnetic interference absorbing sheet using a metal fine wire pattern sheet in which multiple loop-shaped conductive patterns are formed in a matrix on a resin substrate. The electromagnetic interference type electromagnetic interference absorbing sheet of Patent Document 1 is thought to have frequency selectivity that absorbs electromagnetic waves of specific frequencies and transmits electromagnetic waves of specific frequencies, and can be used as a sheet-shaped bandpass filter. Here, Patent Document 1 states that printing methods and the like can be used as a method for manufacturing the above-mentioned metal fine wire pattern. 【0006】 However, while conductive inks are used in printing methods, there are limitations to wire thinning using conductive inks, making it difficult to form fine wire patterns that can handle high-frequency bands. Furthermore, conductive inks contain electrically insulating vehicles, which limits their conductivity. In addition, when resin substrates are used, the adhesion between the metal wire pattern and the resin substrate is low, making it difficult to improve the reliability of the metal wire pattern sheet. Therefore, improving the reliability of the metal wire pattern sheet limits the types of substrates that can be used. 【0007】 Furthermore, Patent Document 2 proposes an electromagnetic wave shielding material using a metal fine wire pattern sheet having a patterned metal foil layer on an electrically insulating substrate. The electromagnetic wave shielding material of Patent Document 2 has frequency selectivity that shields only electromagnetic waves in a specific frequency band and can be used as a sheet-type bandpass filter. Patent Document 2 proposes that the above-mentioned metal fine wire pattern be formed by an etching method. 【0008】In this case, there is no problem with the conductivity of the metal wire patterns formed by the etching method. However, while the etching method can form mesh-like metal wire patterns such as grids or nets where the metal wires forming the pattern are interconnected, it is not possible to form patterns where the metal wires forming the pattern are not interconnected and are isolated, such as loop-shaped metal wire patterns, due to limitations in the mask shapes that can be used in the etching process. 【0009】 JP2022-135025A JP11-251784A 【0010】 This invention solves the above problem and provides a method for manufacturing a metal fine wire pattern sheet that can be used as a bandpass filter having frequency selectivity that shields radio waves of a specific frequency while transmitting radio waves of a specific frequency. 【0011】 The present invention relates to a method for manufacturing a metal fine wire pattern sheet, comprising a base layer and a metal fine wire pattern layer, and is characterized by comprising: a first step of forming a photoresist layer on the conductive surface of a matrix having conductivity on at least its surface; a second step of removing a part of the photoresist layer formed in the first step by photolithography to form a resist body for forming a fine wire pattern; a third step of electrodepositing a metal onto the conductive surface of the matrix on which the resist body for forming a fine wire pattern was formed in the second step by electroforming to form a metal fine wire pattern layer; and a fourth step of transferring the metal fine wire pattern layer formed in the third step from the matrix onto the base layer and arranging the metal fine wire pattern layer on the surface of the base layer to form a metal fine wire pattern sheet. 【0012】 The present invention's method for manufacturing a bandpass filter sheet is characterized by manufacturing a bandpass filter sheet using the present invention's method for manufacturing a metal fine wire pattern sheet. 【0013】The metal fine wire pattern sheet of the present invention comprises a base layer, an adhesive layer, and a metal fine wire pattern layer, wherein the metal fine wire pattern layer is arranged on one side of the base layer via the adhesive layer, the thickness of the adhesive layer is 20 to 100 μm, the metal fine wire pattern layer is composed of a metallic material including at least one selected from the group consisting of silver, copper, copper alloy, nickel, and nickel alloy, the line width of the metal fine wire pattern layer is 5 μm or more and 500 μm or less, its thickness is 1 μm or more and 100 μm or less, and the metal fine wires forming the pattern of the metal fine wire pattern layer are not connected to each other and are isolated for each pattern. 【0014】 The bandpass filter sheet of the present invention is characterized by using the metal fine wire pattern sheet of the present invention. 【0015】 According to this invention, it is possible to manufacture a metal fine wire pattern sheet and a bandpass filter sheet using the same, which have high frequency selectivity that shields radio waves of a specific frequency while transmitting radio waves of a specific frequency, are compatible with high frequency bands, have conductive, adhesive and highly reliable fine wire patterns, and have a high degree of freedom in the shape of the pattern that can be formed. 【0016】 Figures 1A to 1H are schematic cross-sectional views showing an example of the first half of the manufacturing process for the metal fine wire pattern sheet of the first embodiment. Figures 2A to 2J are schematic cross-sectional views showing an example of the second half of the manufacturing process for the metal fine wire pattern sheet of the first embodiment. Figures 3A to 3C are schematic cross-sectional views showing an example of the transfer process for the metal fine wire pattern sheet of the second embodiment. Figures 4A to 4D are schematic cross-sectional views showing an example of the transfer process for the metal fine wire pattern sheet of the third embodiment. Figure 5 is a schematic diagram showing the pattern shape of the metal fine wire pattern layer of the bandpass filter sheet of Example 1. Figure 6 is a diagram showing the transmission spectrum of the bandpass filter sheet of Example 1. Figure 7 is a diagram showing the reflection spectrum of the bandpass filter sheet of Example 1. 【0017】 <Method for Manufacturing Metal Fine Wire Pattern Sheets> First, embodiments of the method for manufacturing metal fine wire pattern sheets according to the present invention will be described in the order of the first embodiment, the second embodiment, and the third embodiment. 【0018】(First Embodiment) The first embodiment of the present invention is a method for manufacturing a metal wire pattern sheet, comprising a base layer and a metal wire pattern layer, comprising: a first step of forming a photoresist layer on the conductive surface of a matrix having conductivity on at least its surface; a second step of removing a part of the photoresist layer formed in the first step by photolithography to form a resist body for forming a wire pattern; a third step of electrodepositing a metal onto the conductive surface of the matrix on which the resist body for forming a wire pattern was formed in the second step by electroforming to form a metal wire pattern layer; and a fourth step of transferring the metal wire pattern layer formed in the third step from the matrix onto the base layer and arranging the metal wire pattern layer on the surface of the base layer to form a metal wire pattern sheet. 【0019】 In the manufacturing method of the metal fine wire pattern sheet of this embodiment, by combining photolithography, electroforming, and transfer methods, it is possible to efficiently manufacture a metal fine wire pattern sheet that can be used as a bandpass filter having frequency selectivity that shields radio waves of a specific frequency while transmitting radio waves of a specific frequency. 【0020】 More specifically, the manufacturing method for metal fine wire pattern sheets of this embodiment does not use a printing method, but combines an electroforming method and a transfer method, making it possible to form fine wire patterns with high conductivity, adhesion, and reliability. Furthermore, in the manufacturing method of this embodiment, since the fine wire pattern is formed indirectly on the substrate by the transfer method rather than directly on the substrate, the range of substrate types that can be selected can be broadened, resulting in a manufacturing method with high substrate selectivity. Moreover, in the manufacturing method of this embodiment, it is of course possible to form mesh-like metal fine wire patterns such as grid-like or net-like patterns in which the metal fine wires are interconnected, but it is also possible to form isolated metal fine wire patterns in which the metal fine wires forming the pattern are not interconnected and are isolated for each pattern. Here, isolated metal fine wire patterns include, for example, a matrix-shaped pattern in which at least one type of pattern, such as a plurality of rectangular or circular patterns, is arranged vertically and horizontally. 【0021】The manufacturing method of the metal fine wire pattern sheet according to this embodiment will be described below with reference to the drawings. Figure 1 is a schematic cross-sectional view showing an example of the first half of the manufacturing process of the metal fine wire pattern sheet according to this embodiment, and Figure 2 is a schematic cross-sectional view showing an example of the second half of the manufacturing process of the metal fine wire pattern sheet according to this embodiment. 【0022】 <Photolithography Process> First, as shown in Figure 1A, a matrix 10 having conductivity on at least its surface is prepared. The type of matrix 10 is not particularly limited as long as it has conductivity on its surface, but usually a metal plate such as a stainless steel plate is used. 【0023】 Next, as shown in Figure 1B, a photoresist layer 11 is formed on the surface of the matrix 10. Negative and positive type photoresists can be used for the photoresist layer 11, but in this embodiment, an example using a negative type photoresist will be described. The thickness of the photoresist layer 11 is not particularly limited, but in this embodiment, the thickness of the photoresist layer 11 is adjusted by laminating one or more negative type photosensitive dry film resists to match the thickness of the metal fine wire pattern layer to be formed. 【0024】 Next, as shown in Figure 1C, a pattern film mask 12 having a shielding portion 12a corresponding to the metal fine wire pattern to be formed is placed in close contact with the photoresist layer 11. Then, as shown in Figure 1D, exposure is performed by irradiating with ultraviolet light L to form exposed portions 11a and unexposed portions 11b on the photoresist layer 11. After that, as shown in Figures 1E and 1F, the pattern film mask 12 is removed and the unexposed portions 11b are dissolved and removed to form a resist body 11c for forming a fine wire pattern on the mold 10. 【0025】 <Electroforming Process> Next, the mold 10 on which the resist body 11c for forming the fine wire pattern is formed is placed in an electroforming tank (not shown) prepared under predetermined conditions. As shown in Figure 1G, an electrodeposited metal such as nickel, nickel alloy, copper, or copper alloy is electroformed onto the surface of the mold 10 that is not covered by the resist body 11c, to a thickness approximately the same as the thickness of the resist body 11c, thereby forming a metal fine wire pattern layer 13 as an electrodeposited metal layer. 【0026】 Next, as shown in Figure 1H, the resist body 11c for forming the fine wire pattern is removed to obtain a mold 10 with a metal fine wire pattern layer 13 formed on its surface. 【0027】 <Transfer Process> First, as shown in Figure 2A, an adhesive sheet 14 is prepared, which consists of a laminate of a release film 14a and an adhesive layer 14b. 【0028】 Next, as shown in Figures 2B and 2C, the adhesive layer 14b side of the adhesive sheet 14 is bonded onto the metal fine wire pattern layer 13 formed on the mold 10 in the electroforming process described above. 【0029】 Next, as shown in Figure 2D, the integrated product of the adhesive sheet 14 and the metal wire pattern layer 13 is separated from the mold 10, and the metal wire pattern layer 13 is transferred to the adhesive sheet 14. 【0030】 Next, as shown in Figure 2E, the release film 14a is peeled off from the adhesive sheet 14 onto which the metal wire pattern layer 13 has been transferred. Then, as shown in Figure 2F, a base film 15 made of resin film or the like is bonded onto the remaining adhesive layer 14b to produce the metal wire pattern sheet 20 of this embodiment, as shown in Figure 2G, in which the metal wire pattern layer 13 is arranged on one side of the base film 15 (base layer) via the adhesive layer 14b. 【0031】 In the above transfer process, a two-layer adhesive sheet with a release film was used. However, a three-layer adhesive sheet with a release film consisting of a release film / adhesive layer / release film may be prepared first, and one of the release films may be peeled off before use. Alternatively, instead of the above adhesive sheet, an adhesive may be applied directly to the metal fine wire pattern layer 13 formed on the mold 10 to form an adhesive layer, and the base film may be attached on top of that. Furthermore, an adhesive sheet with a base film may be used from the beginning, and the adhesive layer side of the adhesive sheet with a base film may be bonded to the metal fine wire pattern layer 13 formed on the mold 10. This eliminates the need for the step of replacing the release film and the base film. 【0032】<Additional Steps> The method for manufacturing the metal wire pattern sheet of this embodiment may be further modified by the following additional steps. For example, as shown in Figures 2H and 2I, the adhesive layer 16b side of an adhesive sheet 16, which has an adhesive layer 16b formed on a release film 16a, is further bonded to the metal wire pattern layer 13 side of the metal wire pattern sheet 20 produced in the transfer step. At this time, it is preferable to bond them in a vacuum atmosphere so that no gap is formed between the metal wire pattern layer 13 and the adhesive layer 16b. 【0033】 Next, as shown in Figure 2J, by replacing the release film 16a of the bonded adhesive sheets 16 with a base film 17 made of a resin film or the like, a metal wire pattern sheet 30 can be produced that has base films 15 and 17 on both sides of the metal wire pattern layer 13. 【0034】 (Second Embodiment) A second embodiment of the method for manufacturing a metal wire pattern sheet of the present invention will be described with reference to Figure 3. Figure 3 is a schematic cross-sectional view showing an example of the transfer process for a metal wire pattern sheet of the second embodiment. The manufacturing method of this embodiment comprises the same steps as the method for manufacturing a metal wire pattern of the first embodiment, except that the transfer process is modified as described below. 【0035】 First, as shown in Figure 3A, a metal fine wire pattern layer 13 is formed on the matrix 10 in the same manner as in the first embodiment. 【0036】 Next, as shown in Figure 3B, a resin material 18 is applied to the metal wire pattern layer 13 and cured to form an integrated product of the metal wire pattern layer 13 and the cured resin layer 18. 【0037】 Next, as shown in Figure 3C, the integrated material is peeled from the mold 10 to produce the metal wire pattern sheet 40 of this embodiment, in which the metal wire pattern layer 13 is placed on one side of the resin layer 18 (base layer). 【0038】 Subsequently, if necessary, additional steps can be performed in the same manner as in the first embodiment to produce a metal wire pattern sheet having a base layer on both sides of the metal wire pattern layer. 【0039】(Third Embodiment) A third embodiment of the method for manufacturing the metal fine wire pattern sheet of the present application will be described based on FIG. 4. FIG. 4 is a schematic cross-sectional view showing an example of the transfer process of the metal fine wire pattern sheet of the third embodiment. The manufacturing method of the present embodiment includes the same steps as the manufacturing method of the metal fine wire pattern of the first embodiment, except that the transfer process is changed as follows. 【0040】 First, as shown in FIG. 4A, in the same manner as in the first embodiment, a metal fine wire pattern layer 13 is formed on the master mold 10. 【0041】 Next, as shown in FIG. 4B, the resin material 18 is filled and cured on the metal fine wire pattern layer 13 in the molding die 19, so as to form, as shown in FIG. 4C, an integrated body of the metal fine wire pattern layer 13 and the cured resin layer 18. 【0042】 Subsequently, as shown in FIG. 4D, the integrated body is peeled off from the master mold 10 to produce the metal fine wire pattern sheet 50 of the present embodiment in which the metal fine wire pattern layer 13 is disposed on one side of the resin layer 18 (base material layer). 【0043】 Thereafter, if necessary, an additional process is performed in the same manner as in the first embodiment to produce a metal fine wire pattern sheet provided with base material layers on both sides of the metal fine wire pattern layer. 【0044】 Next, the metal fine wire pattern sheet manufactured by the manufacturing method of the present embodiment will be described based on FIG. 2G. FIG. 2G is a schematic cross-sectional view showing an example of the metal fine wire pattern sheet manufactured by the manufacturing method of the present embodiment. In FIG. 2G, the metal fine wire pattern sheet 20 includes a base material layer 15, an adhesive layer 14b, and a metal fine wire pattern layer 13, and the metal fine wire pattern layer 13 is disposed on one side of the base material layer 15 via the adhesive layer 14b. Further, the thickness of the adhesive layer 14b is set to 20 to 100 μm, the metal fine wire pattern layer 13 is composed of a metal material containing at least one selected from the group consisting of silver, copper, copper alloy, nickel, and nickel alloy, the line width of the metal fine wire pattern layer 13 is set to 5 μm or more and 500 μm or less, and its thickness is set to 1 μm or more and 100 μm or less. Furthermore, the metal fine wires forming the pattern of the metal fine wire pattern layer 13 are not connected to each other and are isolated for each pattern. 【0045】 <Base material layer> As the base material layer, a resin film can be used. Examples of the resin film include resin films made of polyolefin resins (such as polyethylene, polypropylene, etc.), polyester resins (such as polyethylene terephthalate: PET, polyethylene naphthalate: PEN, polybutylene terephthalate: PBT, polybutylene naphthalate: PBN, etc.), olefin resins (such as cycloolefin polymer: CO, etc.), liquid crystal polymers (LCP), etc. Among these, a polyethylene terephthalate (PET) film is more preferable from the viewpoints of mechanical properties and price. 【0046】 The thickness of the base material layer is not particularly limited, but is preferably 10 to 1000 μm, more preferably 25 to 250 μm. 【0047】 <Metal fine wire pattern layer> Examples of the metal material constituting the metal fine wire pattern layer include iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, silver, cadmium, osmium, iridium, platinum, gold, etc. and alloys thereof. From the viewpoint of conductivity, silver, copper, copper alloys, nickel, nickel alloys, etc. are preferable, and nickel alloys are particularly preferable. 【0048】 The line width of the metal fine wire pattern layer is adjusted according to the use of the metal fine wire pattern sheet. The line width of the metal fine wire pattern layer manufactured by the manufacturing method of the present embodiment can be adjusted to 5 μm or more and 500 μm or less, enabling fine wire formation that is difficult to achieve by a printing method using conductive ink. That is, forming a metal fine wire pattern layer with a uniform line width of 50 μm or less is difficult by a printing method using conductive ink, but according to the manufacturing method of the present embodiment, fine wire formation that is difficult by a printing method is possible. Also, when the metal fine wire pattern sheet of the present embodiment is used as a band-pass filter sheet, depending on the radio wave absorption characteristics, a metal fine wire pattern layer with a line width of 50 μm or more may be required, but in the manufacturing method of the present embodiment, by adjusting the exposure mask, a metal fine wire pattern layer with a line width of 50 μm or more can also be easily formed. The line width of the metal fine wire pattern layer is preferably 5 μm or more and 50 μm or less, more preferably 5 μm or more and 40 μm or less. 【0049】 The line width of the metal wire pattern layer can be measured by observing the surface of the metal wire pattern sheet. Furthermore, if the metal wire pattern layer is covered with a material that does not transmit visible light, the line width can be measured by X-ray inspection or CT scan. In addition, the metal elements constituting the metal wire pattern layer can be identified by measuring the cross-section of the metal wire pattern layer using SEM-EDX. 【0050】 Furthermore, the thickness of the metal wire pattern layer manufactured by the manufacturing method of this embodiment can be adjusted according to the application of the metal wire pattern sheet, but is usually set to 1 μm or more and 100 μm or less. In addition, the ratio of the surface area of ​​the metal wire pattern layer to the surface area of ​​the base layer is preferably 10% or more and 50% or less. Furthermore, the electrical resistivity of the metal wire pattern layer is 1 × 10⁻⁶ -6 It is preferable that it is Ω·m or less, and 1 × 10 -7 It is more preferable that the value is Ω·m or less. 【0051】 The pattern shape of the metal wire pattern layer manufactured by the manufacturing method of this embodiment can be arranged in any shape depending on the application of the metal wire pattern sheet. It is possible to arrange mesh-like metal wire patterns such as grids or nets in which the metal wires are interconnected, as well as isolated metal wire patterns in which the metal wires forming the pattern are not interconnected and are isolated for each pattern. As mentioned above, these isolated metal wire patterns cannot be arranged by conventional etching methods. 【0052】 <Adhesive layer> The adhesive layer has the function of joining the base material layer and the metal fine wire pattern layer. 【0053】The adhesive constituting the above-mentioned adhesive layer is not particularly limited, but for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, epoxy adhesives, etc., can be used. In this specification, the term "adhesive" is used consistently, but in this specification, "adhesive" includes both so-called adhesives (which have elasticity and strong adhesive strength from the beginning) and adhesives (which are liquids that react and harden into a solid and have adhesive properties). The thickness of the above-mentioned adhesive layer is not particularly limited as long as it can exhibit the desired adhesive strength, but 20 to 100 μm is preferred. 【0054】 <Method for Manufacturing a Bandpass Filter Sheet> Next, an embodiment of the method for manufacturing a bandpass filter sheet according to the present invention will be described. The method for manufacturing a bandpass filter sheet according to this embodiment is a method for manufacturing a bandpass filter sheet including a substrate layer and a metal wire pattern layer using the method for manufacturing a metal wire pattern sheet according to the present invention described above, and includes: a first step of forming a photoresist layer on the conductive surface of a master mold having conductivity on at least its surface; a second step of removing a part of the photoresist layer formed in the first step by photolithography to form a resist body for forming a wire pattern; a third step of electrodepositing metal by electroforming onto the conductive surface of the master mold on which the resist body for forming a wire pattern was formed in the second step to form a metal wire pattern layer; and a fourth step of transferring the metal wire pattern layer formed in the third step from the master mold onto the substrate layer and arranging the metal wire pattern layer on the surface of the substrate layer to form a metal wire pattern sheet. 【0055】 In the method for manufacturing a bandpass filter sheet according to this embodiment, by combining photolithography, electroforming, and transfer methods, it is possible to manufacture a bandpass filter with good frequency selectivity for electromagnetic waves in the high frequency range from several hundred GHz to the terahertz band. In particular, the bandpass filter manufactured by the manufacturing method of this embodiment can be given a high filtering function that selectively transmits electromagnetic waves in the 170 to 370 GHz band and shields electromagnetic waves of other frequencies. 【0056】More specifically, the manufacturing method for bandpass filter sheets in this embodiment does not use printing, but combines electroforming and transfer methods, making it possible to form highly conductive, adhesive, and reliable fine wire patterns. Furthermore, in this manufacturing method, since the fine wire pattern is formed indirectly on the substrate by the transfer method rather than directly on the substrate, the range of substrate types that can be selected can be broadened, resulting in a manufacturing method with high substrate selectivity. Moreover, in this manufacturing method, it is possible to form mesh-like metal fine wire patterns such as grids and nets in which metal fine wires are interconnected, but it is also possible to form isolated metal fine wire patterns in which the metal fine wires forming the pattern are not interconnected and are isolated for each pattern. Here, isolated metal fine wire patterns include, for example, matrix-shaped patterns in which at least one type of pattern, such as a plurality of rectangular or circular patterns, is arranged vertically and horizontally. 【0057】 The shape of the metal wire pattern layer of the bandpass filter sheet manufactured by the manufacturing method of this embodiment is not particularly limited, but it is preferable to have a matrix shape in which at least one type of isolated pattern, such as a plurality of rectangular or circular shapes, is arranged vertically and horizontally, or a mesh shape such as a grid or net. It is also possible to have a pattern shape that combines a matrix shape and a mesh shape. By having the metal wire pattern layer in such a shape, it is possible to shield (reflect or absorb) radio waves of a specific frequency in the areas where the metal wire pattern layer is arranged, and to transmit radio waves of a specific frequency in the areas where the metal wire pattern layer is not arranged. For this reason, by using the bandpass filter sheet of this embodiment, it is possible to realize a radio wave reflector (absorber) that reflects (or absorbs) radio waves of a specific frequency, or a bandpass filter that transmits radio waves of a specific frequency. 【0058】 Furthermore, the wire width of the metal wires constituting the metal wire pattern layer is preferably 5 μm or more and 500 μm or less. Furthermore, the ratio of the surface area of ​​the metal wire pattern layer to the surface area of ​​the substrate layer is preferably 10% or more and 50% or less. Furthermore, the thickness of the metal wire pattern layer is preferably 1 μm or more and 100 μm or less. 【0059】The metal wire pattern layer can be formed in a single electroforming process if its thickness is equal to or less than the wire width of the metal wire. Furthermore, if the thickness of the metal wire pattern layer is to be greater than or equal to the wire width, a process consisting of forming a photoresist layer, removing the photoresist layer by photolithography, and electroforming is used. This process involves forming a metal wire pattern layer with a thickness equal to the wire width, then forming another photoresist layer, aligning it, removing the photoresist layer in the same location as the metal wire pattern layer, and then performing electroforming. This allows for the formation of an electrodeposited layer thicker than the wire width. While repeating the above process makes it possible to form a metal wire pattern layer with a thickness exceeding twice the wire width, if the aspect ratio of the metal wire pattern layer becomes too large, it becomes prone to distortion during the transfer process to the substrate layer. Therefore, it is preferable to limit the thickness of the metal wire pattern layer to approximately twice the wire width. 【0060】 Furthermore, the electrical resistivity of the above-mentioned metal fine wire pattern layer is 1 × 10⁻⁶ -6 It is preferable that it is Ω·m or less, and 1 × 10 -7 It is more preferable that the resistivity is Ω·m or less. The lower the electrical resistivity, the higher the reflectivity can be for the same pattern. By manufacturing a bandpass filter sheet having the above configuration, high frequency selectivity can be imparted to the bandpass filter sheet. 【0061】 The components of the bandpass filter sheet manufactured by the manufacturing method of this embodiment will be described below with reference to Figure 2G. Figure 2G is a schematic cross-sectional view of a bandpass filter sheet made of a metal wire pattern sheet 20 manufactured by the manufacturing method of this embodiment, in which a metal wire pattern layer 13 is arranged on one side of a base film 15 (base layer) via an adhesive layer 14b. 【0062】 <Substrate Layer> The substrate layer functions as a support for the metal fine wire pattern layer, and also functions as a dielectric layer when the bandpass filter sheet is used as an electromagnetic interference type (λ / 4 type, also called a reflection type) bandpass filter. 【0063】A resin film can be used as the base layer. Examples of such resin films include polyolefin resins (polyethylene, polypropylene, etc.), polyester resins (polyethylene terephthalate: PET, polyethylene naphthalate: PEN, polybutylene terephthalate: PBT, polybutylene naphthalate: PBN, etc.), olefin resins (cycloolefin polymer: CO, etc.), and liquid crystal polymers (LCP). Among these, polyethylene terephthalate (PET) film is more preferred in terms of mechanical properties and cost. Furthermore, when the base layer is to function as a dielectric layer, a resin film made of a cycloolefin polymer with a low dielectric constant is preferred as the base layer. 【0064】 The thickness of the above-mentioned substrate layer is not particularly limited, but is preferably 10 to 1000 μm, and more preferably 25 to 250 μm. 【0065】 <Metal Wire Pattern Layer> The above metal wire pattern layer functions as a radio wave reflection and transmission layer that shields radio waves of specific frequencies while simultaneously imparting frequency selectivity to the bandpass filter sheet, allowing radio waves of specific frequencies to pass through. 【0066】 Examples of metal materials constituting the above-mentioned fine metal wire pattern layer include iron, cobalt, nickel, copper, zinc, ruthenium, rhodium, palladium, silver, cadmium, osmium, iridium, platinum, gold, and alloys thereof. From the viewpoint of conductivity, silver, copper, copper alloys, nickel, nickel alloys, etc., are preferred. 【0067】 <Adhesive Layer> The adhesive layer has the function of joining the substrate layer and the metal fine wire pattern layer, and can also function as the dielectric layer mentioned above together with the substrate layer. 【0068】The adhesive constituting the above-mentioned adhesive layer is not particularly limited, but for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, epoxy adhesives, etc., can be used. In this specification, the term "adhesive" is used consistently, but in this specification, "adhesive" includes both so-called adhesives (which have elasticity and strong adhesive strength from the beginning) and adhesives (which are liquids that react and harden into a solid and have adhesive properties). The thickness of the above-mentioned adhesive layer is not particularly limited as long as it can exhibit the desired adhesive strength, but 20 to 100 μm is preferred. 【0069】 The following describes a bandpass filter sheet manufactured by the manufacturing method of the metal fine wire pattern sheet according to the first embodiment of this application. 【0070】 (Example 1) <Photolithography Process> A stainless steel plate was used as a mold, and a negative-type photosensitive dry film resist was laminated to form a photoresist layer. Using a pattern film mask having shielding areas corresponding to the metal fine-line pattern to be formed, ultraviolet light was irradiated to expose the plate, and the unexposed areas were dissolved and removed to form a resist body for forming a predetermined fine-line pattern on the stainless steel plate. 【0071】 <Electroforming Process> Next, the stainless steel plate on which the resist body for forming the fine wire pattern was formed was placed in an electroforming bath prepared under predetermined conditions. Ni-Co was electroformed as the electrodeposited metal on the surface of the stainless steel plate that was not covered by the resist body, to a thickness approximately the same as the thickness of the resist body for forming the fine wire pattern, and the resist body for forming the fine wire pattern was removed, thereby forming a 40 μm thick metal fine wire pattern layer (electrodeposited layer) consisting of a Ni-Co alloy layer on the stainless steel plate. 【0072】<Transfer Process> Next, a base material-less double-sided adhesive sheet (manufactured by Nichiei Shinka Co., Ltd., product name: MHM-FWD50) with a three-layer structure consisting of release film / adhesive layer (thickness: 50 μm) / release film was used for the transfer process by peeling off one side of the release film and using it as the adhesive sheet. After that, the remaining release film of the adhesive sheet was replaced with a 75 μm PET film (manufactured by Toyobo Co., Ltd., product name: A4380), and a primary bandpass filter sheet was fabricated by forming a predetermined metal fine wire pattern on the PET film (base layer) via the adhesive layer. 【0073】 <Additional Steps> Finally, an adhesive sheet, from which one side of the release film of the substrate-less double-sided adhesive sheet (manufactured by Nichiei Shinka Co., Ltd., product name: MHM-FWD50) was peeled off, was bonded to the metal wire pattern layer side of the fabricated primary bandpass filter sheet. At this time, the bonding was carried out in a vacuum atmosphere to prevent the formation of a gap between the metal wire pattern layer and the adhesive sheet. Subsequently, the remaining release film of the bonded adhesive sheet was replaced with the PET film (manufactured by Toyobo Co., Ltd., product name: A4380), thereby fabricating the bandpass filter sheet of Example 1, which has PET film (substrate layer) on both sides of the metal wire pattern layer. 【0074】 Figure 5 schematically shows the pattern shape of the metal wire pattern layer of the bandpass filter sheet of this embodiment. The pattern shape of the metal wire pattern layer shown in Figure 5 is formed from a matrix shape 1 in which multiple rectangular patterns are arranged vertically and horizontally, and a mesh shape 2. Each rectangular pattern constituting the matrix shape 1 has an opening 1a in the center, and the center of each rectangular pattern is positioned at the center of the opening 2a of each mesh in the mesh shape 2. 【0075】 The dimensions of the pattern shape of the metal fine wire pattern layer described above were set as follows, assuming a frequency of 300 GHz for electromagnetic waves to be transmitted through the bandpass filter sheet, in order to find conditions that allow for good transmission of electromagnetic waves with a wider bandwidth. 【0076】As shown in Figure 5, the pitch a of mesh shape 2 is 0.60 mm, the spacing b inside the mesh of mesh shape 2 is 0.56 mm, the line width c of mesh shape 2 is 0.04 mm, the outer length d of the rectangular pattern constituting matrix shape 1 is 0.42 mm, the width e (opening size) of the rectangular pattern is 0.34 mm, and the line width f of the rectangular pattern is 0.04 mm. The arrangement pitch of the rectangular pattern is also set to 0.60 mm, the same as the pitch a of the mesh shape. The vertical and horizontal dimensions of the above pattern shape are the same. 【0077】 (Example 2) In Figure 5, the pitch a of mesh shape 2 was set to 0.43 mm, the spacing b inside the mesh of mesh shape 2 was set to 0.415 mm, the line width c of mesh shape 2 was set to 0.015 mm, the outer length d of the rectangular pattern constituting matrix shape 1 was set to 0.285 mm, the width (opening size) e of the rectangular pattern was set to 0.255 mm, and the line width f of the rectangular pattern was set to 0.015 mm. The arrangement pitch of the rectangular pattern was set to the same 0.43 mm as the pitch a of the mesh shape, and the thickness of the electrodeposited layer was set to 10 μm. Except for these differences, the bandpass filter sheet of Example 2 was manufactured in the same manner as in Example 1. 【0078】 (Example 3) In Figure 5, the pitch a of mesh shape 2 was set to 0.38 mm, the spacing b inside the mesh of mesh shape 2 was set to 0.37 mm, the line width c of mesh shape 2 was set to 0.005 mm, the outer length d of the rectangular pattern constituting matrix shape 1 was set to 0.265 mm, the width (opening size) e of the rectangular pattern was set to 0.255 mm, the line width f of the rectangular pattern was set to 0.05 mm, the arrangement pitch of the rectangular pattern was set to 0.38 mm, the same as the pitch a of the mesh shape, and the thickness of the electrodeposited layer was set to 5 μm. Except for these other conditions, the bandpass filter sheet of Example 3 was manufactured in the same manner as in Example 1. 【0079】Next, the radio wave transmission and reflection characteristics of the bandpass filter sheet of Example 1 were measured using a THz spectroscopic imaging device (Advantest Corporation, product name: TAS-7400TS). The measurement conditions were: frequency range: 0 to 3 THz, frequency resolution: 1.9 GHz, number of integrations: 4096. In addition, to eliminate the influence on the spectroscopic measurement, the measurements were performed in a desiccator with a humidity of 10% or less. For transmission measurements, background measurements were performed without the sample in place, and for reflection measurements, background measurements were performed using a metal standard plate as the sample before evaluating the measurement sample. 【0080】 Based on the above measurement results, Figure 6 shows the transmission spectrum and Figure 7 shows the reflection spectrum of the bandpass filter sheet of Example 1 in the 100-700 GHz range. From Figures 6 and 7, it was confirmed that the bandpass filter sheet of Example 1 is a film that has a bandpass filter function, with low reflection and high transmission of radio waves from approximately 220 GHz to approximately 380 GHz, thus transmitting almost all radio waves in this band, and cutting off radio waves around 150 GHz by reflection. 【0081】 Furthermore, when similar measurements were performed on Example 2, the results showed that the transmission attenuation of 180 GHz radio waves was large, and the reflection attenuation of 300 GHz to 400 GHz radio waves was large. Similarly, when measurements were performed on Example 3, the results were the same as in Example 2, showing that the transmission attenuation of 180 GHz radio waves was large, and the reflection attenuation of 300 GHz to 400 GHz radio waves was large. From these results, it was confirmed that the bandpass filter sheets of Example 2 and Example 3 are films that have a bandpass filter function that selectively cuts 180 GHz radio waves. 【0082】 Furthermore, visual inspection of the measurement samples from Examples 1, 2, and 3 revealed that the transparency of the measurement samples was greatest in Example 3, followed by Example 2 and then Example 1. This is likely because reducing the line width of the metal fine wire pattern layer reduced the total area of ​​the metal fine wire pattern layer in the measurement sample, thereby improving the transparency of the measurement sample. 【0083】With respect to embodiments of the present application including the above-described Examples 1 to 3, the following additional embodiments are further disclosed. (Additional Embodiment 1) A method for manufacturing a metal wire pattern sheet comprising a substrate layer and a metal wire pattern layer, comprising: a first step of forming a photoresist layer on the conductive surface of a matrix having conductivity on at least its surface; a second step of removing a part of the photoresist layer formed in the first step by photolithography to form a resist body for forming a wire pattern; a third step of electrodepositing a metal onto the conductive surface of the matrix on which the resist body for forming a wire pattern was formed in the second step by electroforming to form a metal wire pattern layer; and a fourth step of transferring the metal wire pattern layer formed in the third step from the matrix onto the substrate layer and arranging the metal wire pattern layer on the surface of the substrate layer to form a metal wire pattern sheet. (Appendix 2) The method for manufacturing a metal wire pattern sheet according to Appendix 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the adhesive layer by bonding an adhesive layer onto the metal wire pattern layer, and then peeling the integrated product from the master mold. (Appendix 3) The method for manufacturing a metal wire pattern sheet according to Appendix 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the cured resin layer by applying a resin material onto the metal wire pattern layer and curing it, and then peeling the integrated product from the master mold. (Appendix 4) The method for manufacturing a metal wire pattern sheet according to Appendix 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the cured resin layer by filling a resin material onto the metal wire pattern layer in a molding die and curing it, and then peeling the integrated product from the master mold. (Appendix 5) A method for manufacturing a metal wire pattern sheet according to any one of the appendix embodiments 1 to 4, further comprising the step of laminating a substrate to the metal wire pattern layer side of the metal wire pattern sheet manufactured in the fourth step.(Appendix 6) A method for manufacturing a metal wire pattern sheet according to any one of Appendix 1 to 5, wherein the metal wire pattern layer includes a matrix shape in which at least one type of rectangular or circular pattern is arranged vertically and horizontally. (Appendix 7) A method for manufacturing a metal wire pattern sheet according to any one of Appendix 1 to 6, wherein the metal wire pattern layer includes a mesh shape. (Appendix 8) A method for manufacturing a metal wire pattern sheet according to any one of Appendix 1 to 7, wherein the wire width of the metal wires constituting the metal wire pattern layer is 5 μm or more and 500 μm or less. (Appendix 9) A method for manufacturing a metal wire pattern sheet according to any one of Appendix 1 to 8, wherein the ratio of the surface area of ​​the metal wire pattern layer to the surface area of ​​the base layer is 10% or more and 50% or less. (Appendix 10) A method for manufacturing a metal wire pattern sheet according to any one of Appendix 1 to 9, wherein the thickness of the metal wire pattern layer is 1 μm or more and 100 μm or less. (Appendix 11) The electrical resistivity of the metal wire pattern layer is 1 × 10. -6A method for manufacturing a metal fine wire pattern sheet according to any of the appendix embodiments 1 to 10, wherein the resistance is Ω·m or less. (Appendix Embodiment 12) A method for manufacturing a bandpass filter sheet comprising a substrate layer and a metal fine wire pattern layer, comprising: a first step of forming a photoresist layer on the conductive surface of a matrix having conductivity on at least its surface; a second step of removing a part of the photoresist layer formed in the first step by photolithography to form a resist body for forming a fine wire pattern; a third step of electrodepositing a metal onto the conductive surface of the matrix on which the resist body for forming a fine wire pattern was formed in the second step by electroforming to form a metal fine wire pattern layer; and a fourth step of transferring the metal fine wire pattern layer formed in the third step from the matrix onto the substrate layer and arranging the metal fine wire pattern layer on the surface of the substrate layer to form a metal fine wire pattern sheet. (Appendix 13) The method for manufacturing a bandpass filter sheet according to appendix 12, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the adhesive layer by bonding an adhesive layer onto the metal wire pattern layer, and then peeling the integrated product from the mold. (Appendix 14) The method for manufacturing a bandpass filter sheet according to appendix 12, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the cured resin layer by applying a resin material onto the metal wire pattern layer and curing it, and then peeling the integrated product from the mold. (Appendix 15) The method for manufacturing a bandpass filter sheet according to appendix 12, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of filling the metal wire pattern layer with a resin material in a molding die and curing it to form an integrated product of the metal wire pattern layer and the cured resin layer, and then peeling the integrated product from the master mold. (Appendix 16) The method for manufacturing a bandpass filter sheet according to any one of appendix 12 to 15, further including a step of laminating a substrate to the metal wire pattern layer side of the metal wire pattern sheet produced in the fourth step.(Appendix 17) A method for manufacturing a bandpass filter sheet according to any one of appendix forms 12 to 16, wherein the metal fine wire pattern layer includes a matrix shape in which at least one type of rectangular or circular pattern is arranged vertically and horizontally. (Appendix 18) A method for manufacturing a bandpass filter sheet according to any one of appendix forms 12 to 17, wherein the metal fine wire pattern layer includes a mesh shape. (Appendix 19) A method for manufacturing a bandpass filter sheet according to any one of appendix forms 12 to 18, wherein the line width of the metal fine wires constituting the metal fine wire pattern layer is 5 μm or more and 500 μm or less. (Appendix 20) A method for manufacturing a bandpass filter sheet according to any one of appendix forms 12 to 19, wherein the ratio of the surface area of ​​the metal fine wire pattern layer to the surface area of ​​the substrate is 10% or more and 50% or less. (Appendix 21) A method for manufacturing a bandpass filter sheet according to any one of appendix forms 12 to 20, wherein the thickness of the metal fine wire pattern layer is 1 μm or more and 100 μm or less. (Appendix 22) The electrical resistivity of the metal fine wire pattern layer is 1 × 10. -6A method for manufacturing a bandpass filter sheet according to any of the appendix embodiments 12 to 21, wherein the density is Ω·m or less. (Appendix Embodiment 23) A metal fine wire pattern sheet comprising a base layer, an adhesive layer, and a metal fine wire pattern layer, wherein the metal fine wire pattern layer is arranged on one side of the base layer via the adhesive layer, the thickness of the adhesive layer is 20 to 100 μm, the metal fine wire pattern layer is composed of a metallic material including at least one selected from the group consisting of silver, copper, copper alloy, nickel, and nickel alloy, the line width of the metal fine wire pattern layer is 5 μm or more and 500 μm or less, and its thickness is 1 μm or more and 100 μm or less, and the metal fine wires forming the pattern of the metal fine wire pattern layer are not connected to each other and are isolated for each pattern. (Appendix Embodiment 24) The metal fine wire pattern sheet according to appendix embodiment 23, wherein the metal fine wire pattern layer is composed of a metallic material including a nickel alloy, and the line width of the metal fine wire pattern layer is 5 μm or more and 40 μm or less. (Appendix Form 25) A bandpass filter sheet comprising a base layer, an adhesive layer, and a metal fine wire pattern layer, wherein the metal fine wire pattern layer is disposed on one side of the base layer via the adhesive layer, the thickness of the adhesive layer is 20 to 100 μm, the metal fine wire pattern layer is composed of a metallic material including at least one selected from the group consisting of silver, copper, copper alloy, nickel, and nickel alloy, the line width of the metal fine wire pattern layer is 5 μm or more and 500 μm or less, and its thickness is 1 μm or more and 100 μm or less, and the metal fine wires forming the pattern of the metal fine wire pattern layer are not connected to each other and are isolated for each pattern. (Appendix Form 26) The bandpass filter sheet according to Appendix Form 25, wherein the metal fine wire pattern layer is composed of a metallic material including a nickel alloy, and the line width of the metal fine wire pattern layer is 5 μm or more and 40 μm or less. 【0084】This application can also be implemented in forms other than those described above. The embodiments disclosed herein are examples and are not limiting. The scope of this application shall be interpreted in accordance with the claims attached, which take precedence over the description in the above specification, and all modifications within the scope equivalent to the claims shall be included in the claims. 【0085】 1 Matrix shape 1a Opening 2 Mesh shape 2a Opening 10 Master mold 11 Photoresist layer 12 Pattern film mask 13 Metal wire pattern layer 14 Adhesive sheet 15 Substrate film (substrate layer) 16 Adhesive sheet 17 Substrate film 18 Resin material (resin layer) 19 Molding die 20, 30, 40, 50 Metal wire pattern sheet

Claims

1. A method for manufacturing a metal wire pattern sheet comprising a base layer and a metal wire pattern layer, comprising: a first step of forming a photoresist layer on the conductive surface of a matrix having conductivity on at least its surface; a second step of removing a portion of the photoresist layer formed in the first step by photolithography to form a resist body for forming a wire pattern; a third step of electrodepositing metal onto the conductive surface of the matrix on which the resist body for forming a wire pattern was formed in the second step by electroforming to form a metal wire pattern layer; and a fourth step of transferring the metal wire pattern layer formed in the third step from the matrix onto the base layer and arranging the metal wire pattern layer on the surface of the base layer to form a metal wire pattern sheet.

2. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the adhesive layer by bonding an adhesive layer onto the metal wire pattern layer, and then peeling the integrated product from the mold.

3. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of forming an integrated product of the metal wire pattern layer and the cured resin layer by applying a resin material onto the metal wire pattern layer and curing it, and then peeling the integrated product from the mold.

4. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the transfer step of the metal wire pattern layer in the fourth step includes a step of filling the metal wire pattern layer with a resin material in a molding die and curing it to form an integrated product of the metal wire pattern layer and the cured resin layer, and then peeling the integrated product from the master mold.

5. A method for manufacturing a metal wire pattern sheet according to claim 1, further comprising the step of laminating a substrate to the metal wire pattern layer side of the metal wire pattern sheet manufactured in the fourth step.

6. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the metal wire pattern layer includes a matrix shape in which at least one of a plurality of rectangular or circular patterns are arranged vertically and horizontally.

7. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the metal wire pattern layer includes a mesh shape.

8. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the wire width of the metal wires constituting the metal wire pattern layer is 5 μm or more and 500 μm or less.

9. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the ratio of the surface area of ​​the metal wire pattern layer to the surface area of ​​the base material layer is 10% or more and 50% or less.

10. The method for manufacturing a metal wire pattern sheet according to claim 1, wherein the thickness of the metal wire pattern layer is 1 μm or more and 100 μm or less.

11. The electrical resistivity of the metal fine wire pattern layer is 1 × 10 -6 A method for manufacturing a metal fine wire pattern sheet according to claim 1, wherein the ohm is less than or equal to Ω·m.

12. A method for manufacturing a bandpass filter sheet, characterized by manufacturing a bandpass filter sheet using the method for manufacturing a metal fine wire pattern sheet described in any one of claims 1 to 11.

13. A metal wire pattern sheet comprising a base layer, an adhesive layer, and a metal wire pattern layer, wherein the metal wire pattern layer is disposed on one side of the base layer via the adhesive layer, the thickness of the adhesive layer is 20 to 100 μm, the metal wire pattern layer is composed of a metallic material including at least one selected from the group consisting of silver, copper, copper alloy, nickel, and nickel alloy, the wire width of the metal wire pattern layer is 5 μm or more and 500 μm or less, and its thickness is 1 μm or more and 100 μm or less, and the metal wires forming the pattern of the metal wire pattern layer are not connected to each other and are isolated for each pattern.

14. The metal fine wire pattern sheet according to claim 13, wherein the metal fine wire pattern layer is made of a metal material including a nickel alloy, and the line width of the metal fine wire pattern layer is 5 μm or more and 40 μm or less.

15. A bandpass filter sheet characterized by using the metal fine wire pattern sheet described in claim 13 or 14.

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