JP2021163989A - Film antenna and manufacturing method of the film antenna - Google Patents

Abstract

To provide a film antenna that enables an antenna pattern to be simply formed, and provide a manufacturing method of the film antenna.SOLUTION: A film antenna 10 includes a thin film layer 13 containing a part 16a constituting an antenna pattern and a part 16b which does not constitute the antenna pattern in the same flat face on a face of a substrate 12. The part 16a constituting the antenna pattern is constituted by a conductive film containing a metal. The part 16b which does not constitute the antenna pattern is constituted by a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide.SELECTED DRAWING: Figure 2

Description

The present invention relates to a film antenna and a method for manufacturing a film antenna.

A thin film-shaped antenna (film antenna) is known as a small antenna mounted on an electronic device such as a mobile communication terminal or a vehicle such as an automobile.

Japanese Unexamined Patent Publication No. 2012-024167

In the conventional film antenna, the antenna pattern (conductive pattern) is formed by etching or the like (Patent Document 1 or the like). When the antenna pattern of a film antenna is formed by etching, it is not possible to easily form the antenna pattern because a step of removing a part of the metal portion by etching is required.

An object to be solved by the present invention is to provide a film antenna and a method for manufacturing a film antenna, which facilitates the formation of an antenna pattern.

In order to solve the above problems, the film antenna according to the present invention has a thin film layer on the surface of the substrate, in which a portion constituting the antenna pattern and a portion not forming the antenna pattern are included in the same plane, and the antenna pattern is described. The portion constituting the antenna pattern is composed of a conductive film containing a metal, and the portion not constituting the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide. The gist is that.

Further, another film antenna according to the present invention has a thin film layer including a portion constituting the antenna pattern on the surface of the substrate, and the portion constituting the antenna pattern is composed of a conductive film containing a metal. The gist is that a discontinuous film composed of a metal oxide is provided on the surface of the thin film layer.

In the film antenna according to the present invention, it is preferable to have a discontinuous film composed of a metal oxide on the surface of the thin film layer.

The thickness of the discontinuous film is preferably 0.5 nm or more and 5.0 nm or less.

It is preferable that a mask covering the portion is arranged on the surface of the portion forming the antenna pattern, and the portion is not covered with the mask on the surface of the portion not forming the antenna pattern.

The conductive film preferably contains at least one metal of silver, copper, titanium, a silver alloy, a copper alloy, and a titanium alloy.

The discontinuous film preferably contains an oxide of at least one metal of titanium, tin, tantalum, and zinc.

The method for manufacturing a film antenna according to the present invention is a method for manufacturing a film antenna having an antenna pattern on the surface of a substrate, which includes a step of forming a metal thin film on the surface of the substrate and an antenna among the metal thin films. The portion that does not correspond to the pattern is oxidized, nitrided, or carbonized to form a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide, and the portion of the metal thin film that corresponds to the antenna pattern. The gist is to have a step of forming a conductive film containing a metal without oxidizing, nitriding, or carbonizing.

In the method for manufacturing a film antenna according to the present invention, a mask is placed on the surface of the portion of the metal thin film corresponding to the antenna pattern, and the portion of the metal thin film not corresponding to the antenna pattern is oxidized, nitrided, or It is preferable to carbonize.

Then, it is preferable to further have a step of removing the non-conductive film.

Then, oxidation, nitriding, or carbonization of the portion of the metal thin film that does not correspond to the antenna pattern is preferably performed by plasma treatment.

According to the film antenna according to the present invention, a portion having a thin film layer in which a portion forming the antenna pattern and a portion not forming the antenna pattern are included in the same plane on the surface of the substrate, and forming the antenna pattern. Is composed of a conductive film containing a metal, and the portion that does not form the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide. Pattern formation becomes easy.

Further, according to another film antenna according to the present invention, a thin film layer including a portion constituting the antenna pattern is provided on the surface of the substrate, and the portion constituting the antenna pattern is a conductive film containing a metal. Since it is configured and has a discontinuous film composed of a metal oxide on the surface of the thin film layer, the formation of an antenna pattern becomes easy.

According to the method for manufacturing a film antenna according to the present invention, there is a method for manufacturing a film antenna having an antenna pattern on the surface of a substrate, which is a step of forming a metal thin film on the surface of the substrate and a method of forming the metal thin film. Of these, the portion that does not correspond to the antenna pattern is oxidized, nitrided, or carbonized to form a non-conductive material containing at least one of metal oxide, metal nitride, and metal carbide, and corresponds to the antenna pattern among the metal thin films. Since the step of forming a conductive film containing a metal without oxidizing, nitriding, or carbonizing the portion to be formed is provided, the formation of the antenna pattern becomes simple.

It is a top view of the film antenna which concerns on one Embodiment of this invention. FIG. 5 is a cross-sectional view taken along the line AA of the film antenna shown in FIG. It is a process drawing explaining the manufacturing process of the film antenna shown in FIG. It is sectional drawing of the film antenna which concerns on other embodiment of this invention. It is sectional drawing of the film antenna which concerns on other embodiment of this invention. It is sectional drawing of the film antenna which concerns on other embodiment of this invention. It is sectional drawing of the film antenna which concerns on other embodiment of this invention. It is a perspective view of another connection structure. It is a side view of the connection structure shown in FIG.

The film antenna according to the present invention will be described in detail.

FIG. 1 shows the appearance of a film antenna according to an embodiment of the present invention. FIG. 2 shows a cross-sectional view taken along the line AA of the film antenna shown in FIG.

The film antenna 10 has a substrate 12, a thin film layer 13, and a mask 22. The thin film layer 13 includes a portion 16a (antenna pattern 16a) forming the antenna pattern and a portion 16b not forming the antenna pattern in the same plane. The portion 16a constituting the antenna pattern is composed of a conductive film containing a metal, and the portion 16b not forming the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride and a metal carbide. Has been done.

The thin film layer 13 has a three-layer structure, and discontinuous films 14 and 18 made of metal oxides are arranged on both sides of the intermediate thin film 16 including the portion 16a forming the antenna pattern, respectively. The portion of the intermediate thin film 16 covered with the mask 22 is formed of a conductive film containing a metal, and is a portion 16a forming an antenna pattern. The portion not covered by the mask 22 is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide, and is a portion 16b that does not form an antenna pattern.

The antenna pattern 16a constitutes an antenna element (antenna element). The feeding portion 28 is connected to the antenna pattern 16a via the wiring pattern 26. By attaching a power supply terminal (not shown) to the power supply unit 28, a receiver for terrestrial digital broadcasting or television broadcasting, a GPS device, a DAB (Digital Audio Broadcast) receiver, and a film antenna 10 are provided in the vehicle. Will be connected. The wiring pattern 26 is not particularly limited, but can be formed from a conductive paste or the like. Examples of the metal of the conductive paste include silver, copper and aluminum.

The substrate 12 is a base material for forming the thin film layer 13 and the like. The substrate 12 may be thin in the form of a film or sheet, or may be in the form of a plate. The substrate 12 may have light transmittance or may not have light transmission. The light transmittance means that the value of the transmittance in the wavelength region of 360 to 830 nm is 50% or more. When the substrate 12 is a light-transmitting substrate, the visibility is excellent and the design is improved. The material of the light-transmitting substrate is not particularly limited as long as it has light-transparency, can form a thin film on the surface thereof without any trouble, and has flexibility. For example, a light-transmitting polymer film, flexible glass, and the like can be mentioned.

Specific examples of the material of the light-transmitting polymer film include polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, polyamide, polybutylene terephthalate, and polyether ether ketone. , Polyvinyl chloride, polyvinylidene chloride, triacetyl cellulose, polyurethane, cycloolefin polymer, polyethylene naphthalate, polyimide, tetrafluoroethylene-ethylene copolymer and the like. These may be used alone or in combination of two or more. Among these, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, cycloolefin polymer, and polyethylene naphthalate are more preferable materials from the viewpoints of excellent light transmission, durability, and processability. Further, the light-transmitting polymer film is relatively preferably crystalline and has a small coefficient of linear expansion from the viewpoint of excellent heat resistance and the like. For example, polyethylene terephthalate, polyimide and the like can be mentioned.

The thickness of the light-transmitting polymer film may be appropriately adjusted in consideration of the application, optical properties, material type, durability and the like. For example, 25 μm or more is preferable from the viewpoint of being less likely to wrinkle or break during processing. More preferably, it is 50 μm or more. Further, from the viewpoint of flexibility, handleability, economy and the like, 500 μm or less is preferable. More preferably, it is 250 μm or less. The thickness of the flexible glass may be appropriately adjusted in consideration of the application, optical characteristics, durability and the like.

The conductive film which is the portion 16a constituting the antenna pattern contains a metal. The conductive film may be composed of only a metal component, or may contain an oxide component, a nitride component, a carbide component, or the like of a metal.

From the viewpoint of conductivity, the conductive film preferably has a surface resistance of 1000 Ω / □ or less. More preferably, it is 100 Ω / □ or less. The surface resistance can be measured by a Staroresta-GX MCP-T700 low resistivity meter (manufactured by Mitsubishi Chemical Analytech).

Examples of the metal constituting the conductive film include silver, silver alloy, gold, platinum, copper, aluminum, aluminum alloy, iron, iron alloy, titanium, titanium alloy and the like. Of these, silver, silver alloys, copper, and copper alloys are preferable from the viewpoint of light transmission and the like. Further, a silver alloy is more preferable from the viewpoint of improving durability against the environment such as heat, light, and water vapor. As the silver alloy, a silver alloy containing silver as a main component and containing at least one kind of metal element such as copper, bismuth, gold, palladium, platinum and titanium is preferable. More preferably, a silver alloy containing copper (Ag—Cu based alloy), a silver alloy containing bismuth (Ag—Bi based alloy), a silver alloy containing titanium (Ag—Ti based alloy) and the like are preferable.

The thickness of the conductive film is preferably 3.0 nm or more and 30.0 nm or less. When the thickness of the conductive film is 3.0 nm or more, the stability is excellent. From this point of view, the thickness of the conductive film is more preferably 5.0 nm or more, still more preferably 7.0 nm or more. Further, when the thickness of the conductive film is 30.0 nm or less, light transmission and economy are excellent. From this point of view, the thickness of the conductive film is more preferably 20 nm or less, still more preferably 11 nm or less. The thickness of the conductive film can be measured using a field emission electron microscope (HRTEM).

The non-conductive film, which is the portion 16b that does not form the antenna pattern, contains at least one of a metal oxide, a metal nitride, and a metal carbide. The non-conductive film may be composed of only one kind or two or more kinds of metal oxides, metal nitrides and metal carbides, or may contain a metal component. The non-conductive film is preferably composed of a non-conductive metal that is the same as the metal constituting the conductive film.

From the viewpoint of non-conductive property, the non-conductive film has a surface resistance of 1000 Ω / □ or more. More preferably, it is 2000 Ω / □ or more. The surface resistance can be measured by a Staroresta-GX MCP-T700 low resistivity meter (manufactured by Mitsubishi Chemical Analytech).

The thickness of the non-conductive film may be the same as the thickness of the conductive film. The thickness of the non-conductive film can be measured using a field emission electron microscope (HRTEM).

The discontinuous films 14 and 18 are composed of a film composed of a metal oxide. The discontinuous membrane refers to a state in which the membrane is not continuous and there are pores. For example, it refers to a state in which metal oxides are scattered in dots or islands. Metal oxides constituting the discontinuous films 14 and 18 include titanium oxide, indium oxide, tin oxide, indium and tin oxide, magnesium oxide, aluminum oxide, and zirconium oxide. Examples include substances, niobium oxides, cerium oxides, tantalum oxides, and zinc oxides. The discontinuous films 14 and 18 may contain at least one metal oxide of titanium oxide and tin oxide. In particular, it is preferable to contain an oxide of tin. Tin oxide is capable of high-speed film formation and has excellent corrosion resistance.

The discontinuous films 14 and 18 may be composed of only a metal oxide component or may contain a metal component.

The thickness of the discontinuous films 14 and 18 is preferably 0.5 nm or more and 5.0 nm or less. When the thickness of the discontinuous films 14 and 18 is 0.5 nm or more, oxidation of the metal constituting the conductive film is easily suppressed. From this viewpoint, the thickness of the discontinuous films 14 and 18 is more preferably 1.0 nm or more. On the other hand, when the thicknesses of the discontinuous films 14 and 18 are 5.0 nm or less, a non-conductive film is likely to be formed by the plasma treatment described later. From this viewpoint, the thickness of the discontinuous films 14 and 18 is more preferably 4.0 nm or less. The thicknesses of the discontinuous films 14 and 18 can be measured using a field emission electron microscope (HRTEM).

The mask 22 is arranged on the surface of the portion 16a that constitutes the antenna pattern. The mask 22 is not arranged on the surface of the portion 16b that does not form the antenna pattern, and the portion 16b that does not form the antenna pattern is not covered with the mask.

The mask 22 protects the portion of the metal thin film covered with the mask 22 from being subjected to the plasma treatment in the plasma treatment described later. Examples of the material constituting the mask 22 include acrylic resin, olefin resin, vinyl resin, ester resin, and fluororesin. Of these, acrylic resins are particularly preferable from the viewpoints of light transmission, durability, processability, and the like.

The thickness of the mask 22 is preferably 0.005 μm or more and 30 μm or less. When the thickness of the mask 22 is 0.005 μm or more, the effect of protecting the metal thin film is more excellent. From this point of view, the thickness of the mask 22 is more preferably 1.0 μm or more. On the other hand, when the thickness of the mask 22 is 30 μm or less, the appearance, light transmission, and workability are excellent. From this point of view, the thickness of the mask 22 is more preferably 20 μm or less.

The film antenna 10 can be manufactured as follows. First, as shown in FIG. 3A, the substrate 12 is prepared. Next, as shown in FIG. 3B, the discontinuous film 14, the metal thin film 15, and the discontinuous film 18 are laminated in this order on one surface of the substrate 12. Next, as shown in FIG. 3C, the mask 22 is formed at a position corresponding to a portion constituting the antenna pattern when viewed in the thickness direction. Next, plasma treatment is performed from the surface side on which the mask 22 is formed. As a result, the metal thin film 15 at a position corresponding to the portion that does not form the antenna pattern when viewed in the thickness direction is oxidized, nitrided, or carbonized. The metal thin film 15 at a position corresponding to a portion constituting the antenna pattern when viewed in the thickness direction is not oxidized, nitrided, or carbonized. From the above, the film antenna 10 can be manufactured.

The discontinuous film 14, the metal thin film 15, and the discontinuous film 18 can be formed by the vapor phase method. Examples of the vapor phase method include physical vapor deposition (PVD) such as vacuum deposition, sputtering, ion plating, MBE, and laser ablation, and chemical vapor deposition such as thermal CVD and plasma CVD. The method (CVD) can be mentioned. Of these, the sputtering method is more preferable from the viewpoints of obtaining a fine film quality and relatively easy film thickness control.

In the formation of the discontinuous film 14 and the discontinuous film 18, the target of the sputtering method may be a metal or a metal oxide. It may be an alloy of metal and metal oxide. When a metal is targeted, a thin film containing a metal oxide can be obtained by later oxidizing the formed metal thin film. When the metal oxide is targeted, the oxidation process is not required, so that the load of the oxidation treatment after the film formation can be reduced. When the alloy of the metal and the metal oxide is targeted, the load of the oxidation treatment after the film formation can be reduced as compared with the case where the metal is targeted. Further, as compared with the case where the metal oxide is targeted, the film forming rate is high and the electric power at the time of film formation is low, and the damage to the substrate 12 can be suppressed.

The plasma treatment can be performed using a predetermined plasma device. The plasma treatment is a treatment for eliminating a part of the conductivity of the metal thin film 15. In the plasma treatment, a part of the metal thin film 15 can be oxidized, nitrided, or carbonized depending on the type of gas introduced into the furnace. Plasma processing includes microwave energy and high-frequency energy as means for supplying discharge (ionization) energy that sustains discharge plasma. Of these, microwave energy is more preferable from the viewpoint of being able to process a large area quickly.

According to the film antenna 10 having the above configuration, the film antenna 10 has a thin film layer 13 on the surface of the substrate 12 in which the portion 16a constituting the antenna pattern and the portion 16b not forming the antenna pattern are included in the same plane. The portion 16a constituting the above is composed of a conductive film containing a metal, and the portion 16b not forming an antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide. Therefore, the formation of the antenna pattern becomes simple.

Further, according to the film antenna 10 having the above configuration, the step of forming the metal thin film 15 on the surface of the substrate 12 and the metal oxidation by oxidizing, nitriding, or carbonizing the portion of the metal thin film 15 that does not correspond to the antenna pattern. A non-conductive film containing at least one of a substance, a metal nitride, and a metal carbide, and a conductive film containing a metal without oxidizing, nitriding, or carbonizing the portion of the metal thin film 15 corresponding to the antenna pattern. Since the process is included, the formation of the antenna pattern becomes simple.

Next, another embodiment of the film antenna according to the present invention will be described. FIG. 4 shows another embodiment of the film antenna according to the present invention.

The film antenna 20 according to another embodiment has a substrate 12, a thin film layer 17, and a mask 22. The thin film layer 17 includes a portion 16a (antenna pattern 16a) that constitutes an antenna pattern. The portion 16a constituting the antenna pattern is made of a conductive film containing a metal. The thin film layer 17 has a three-layer structure, and discontinuous films 14 and 18 made of metal oxides are arranged on both sides of the portion 16a constituting the antenna pattern in the thickness direction, respectively. The mask 22 is arranged on the surface of the portion 16a that constitutes the antenna pattern.

The film antenna 20 does not have the discontinuous films 14 and 18 and the portion 16b that does not form the antenna pattern at positions corresponding to the portions that do not form the antenna pattern in the thickness direction as compared with the film antenna 10. The point is different. Since the film antenna 20 is the same as the film antenna 10 except for this, the same description will be omitted.

Similar to the film antenna 10, the film antenna 20 is a portion in which a discontinuous film 14, a metal thin film 15, and a discontinuous film 18 are laminated in this order on one surface of the substrate 12 to form an antenna pattern when viewed in the thickness direction. After forming the mask 22 at the position corresponding to the above and performing plasma treatment from the surface side on which the mask 22 is formed, the discontinuous film 14 at the position corresponding to the portion that does not form the antenna pattern when viewed in the thickness direction, It can be manufactured by removing the non-conductive film and the discontinuous film 18.

The non-conductive film and the like can be easily removed by wiping with a cloth or the like, removing with an adhesive tape, cleaning with water or the like, or the like.

The film antenna 20 has the same effect as that of the film antenna 10. Further, since the film antenna 20 has the non-conductive film removed as compared with the film antenna 10, the light transmittance and the designability are improved depending on the metal type. For example, when the metal constituting the non-conductive material is silver or a silver alloy, the non-conductive material has a metallic luster reflection or a glaring feeling, but the removal of the non-conductive material causes a metallic luster reflection or a glaring feeling. Is suppressed, and light transmission and designability are improved as compared with those in which the non-conductive film is not removed.

FIG. 5 shows another embodiment of the film antenna according to the present invention.

The film antenna 30 according to another embodiment has a substrate 12, a metal oxide layer 32, a thin film layer 13, and a mask 22. The thin film layer 13 includes a portion 16a (antenna pattern 16a) forming the antenna pattern and a portion 16b not forming the antenna pattern in the same plane. The portion 16a constituting the antenna pattern is composed of a conductive film containing a metal, and the portion 16b not forming the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride and a metal carbide. Has been done.

The film antenna 30 is different from the film antenna 10 in that it has a metal oxide layer 32 between the substrate 12 and the thin film layer 13. Since the film antenna 30 is the same as the film antenna 10 except for this, the same description will be omitted.

The metal oxide layer 32 functions as a high-refractive index thin film with respect to the conductive film, and can exhibit functions such as enhancing light transmission by being laminated together with the conductive film. Further, by arranging it as a low dielectric constant material, the film antenna 30 can be suitably used for next-generation 5G communication.

Examples of the metal oxide constituting the metal oxide layer 32 include titanium oxide, zinc oxide, indium oxide, tin oxide, indium and tin oxide, magnesium oxide, and aluminum oxidation. Examples include substances, oxides of zirconium, oxides of niobium, and oxides of cerium. These may be contained alone or in combination of two or more. Further, these metal oxides may be a composite oxide in which two or more kinds of metal oxides are composited. Among these, titanium oxide, indium and tin oxide, zinc oxide, tin oxide and the like are preferable from the viewpoint of having a relatively large refractive index with respect to visible light.

The thickness of the metal oxide layer 32 is preferably in the range of 10 to 100 nm. When the thickness of the metal oxide layer 32 is 10 nm or more, the effect of suppressing the migration of the metal of the conductive film is excellent. From this point of view, it is more preferably 15 nm or more, still more preferably 20 nm or more. Further, when the thickness of the metal oxide layer 32 is 100 nm or less, the light transmission is excellent. From this point of view, it is more preferably 80 nm or less, still more preferably 60 nm or less.

The metal oxide layer 32 can be formed by either a vapor phase method or a liquid phase method. As the vapor phase method, the same method as that of the metal thin film 15 can be used. As the liquid phase method, the sol-gel method can be preferably used. Compared with the gas phase method, the liquid phase method does not require evacuation or use a large amount of electric power. Therefore, it is preferable because it is advantageous in terms of cost and is also excellent in productivity.

In the sol-gel method, a coating liquid containing an organic metal compound which is a precursor of a metal oxide is coated in a thin film, and if necessary, dried to form a precursor thin film of the metal oxide thin film, and then this precursor is formed. This is a method of forming a metal oxide thin film by hydrolyzing and condensing an organic metal compound in a body thin film. Examples of the organometallic compound include metal alkoxides, metal acylates, and metal chelates. Examples of means for hydrolyzing / condensing the organic metal compound in the precursor thin film include irradiation and heating of light energy such as ultraviolet rays, electron beams, and X-rays. Of these, ultraviolet irradiation is particularly preferred.

FIG. 6 shows another embodiment of the film antenna according to the present invention.

The film antenna 40 according to another embodiment has a substrate 12, a thin film layer, and a mask 22. The thin film layer has a one-layer structure, and is composed of an intermediate thin film 16 including a portion 16a constituting the antenna pattern. The thin film layer includes a portion 16a (antenna pattern 16a) constituting the antenna pattern and a portion 16b not forming the antenna pattern in the same plane. The portion 16a constituting the antenna pattern is composed of a conductive film containing a metal, and the portion 16b not forming the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride and a metal carbide. Has been done.

The film antenna 40 is different from the film antenna 10 in that discontinuous films 14 and 18 made of metal oxides are not arranged on both sides of the intermediate thin film 16 in the thickness direction. Since the film antenna 40 is the same as the film antenna 10 except for this, the same description will be omitted.

The configuration of the film antenna 40 is particularly effective when the metal of the antenna pattern 16a is a metal such as gold that is not easily oxidized, or a metal such as titanium in which a passivation of an oxide film is likely to be formed on the surface.

FIG. 7 shows another embodiment of the film antenna according to the present invention.

The film antenna 50 according to another embodiment has a substrate 12, a thin film layer 13, and a mask 22. The thin film layer 13 includes a portion 16a (antenna pattern 16a) forming the antenna pattern and a portion 16b not forming the antenna pattern in the same plane. The portion 16a constituting the antenna pattern is composed of a conductive film containing a metal, and the portion 16b not forming the antenna pattern is composed of a non-conductive film containing at least one of a metal oxide, a metal nitride and a metal carbide. Has been done.

The film antenna 40 has a protective film 36 on the surfaces of the mask 22 and the thin film layer 13 via an adhesive layer 34, and further has a hard coat layer 38 on the surface of the protective film 36. The film antenna 40 is different from the film antenna 10 in that it has an adhesive layer 34, a protective film 36, and a hard coat layer 38. Since the film antenna 40 is the same as the film antenna 10 except for this, the same description will be omitted.

The pressure-sensitive adhesive layer 34 is capable of adhering the protective film 36 on the surfaces of the mask 22 and the thin film layer 13. The pressure-sensitive adhesive layer 34 contains a pressure-sensitive adhesive. The adhesive is one that adheres by applying pressure by utilizing the adhesiveness of the surface, and is distinguished from an adhesive that exhibits peeling resistance by solidification as a pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive include an acrylic resin-based pressure-sensitive adhesive, a silicone resin-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. Although the pressure-sensitive adhesive layer 34 is shown here, an adhesive layer containing an adhesive may be used instead of the pressure-sensitive adhesive layer 34.

The thickness of the pressure-sensitive adhesive layer 34 is not particularly limited. For example, it can be 1.0 μm or more and 100 μm or less.

The protective film 36 covers and protects the thin film layer 13. The protective film 36 may have light transmission property or may not have light transmission property. When the protective film 36 is a light-transmitting substrate, the visibility is excellent and the design is improved. The material of the light-transmitting substrate is not particularly limited as long as it has light-transparency, can form a thin film on the surface thereof without any trouble, and has flexibility. For example, a light-transmitting polymer film and the like can be mentioned. Examples of the light-transmitting polymer film used as the protective film 36 include those exemplified in the substrate 12.

The thickness of the protective film 36 is not particularly limited. For example, it can be 12 μm or more and 500 μm or less.

The hard coat layer 38 covers the surface of the thin film layer 13 and the protective film 36, and can prevent the surfaces from being scratched. The thickness of the hard coat layer 38 is preferably 0.4 μm or more from the viewpoint of excellent scratch resistance and the like. It is more preferably 0.6 μm or more, still more preferably 0.8 μm or more. On the other hand, it is preferably 2.0 μm or less from the viewpoint of excellent heat insulation (suppressing the thermal transmission rate to a low level). It is more preferably 1.6 μm or less, still more preferably 1.0 μm or less. As the hard coat layer 38, a layer containing a curable resin and a layer containing an organic-inorganic hybrid material are preferable.

As the curable resin, silicone resin, acrylic resin and the like are preferable. The silicone resin or acrylic resin may be thermosetting, photocurable, or water-curable. As the acrylic resin, acrylic / urethane resin, silicon acrylic resin, acrylic / melamine resin and the like are preferable.

The organic-inorganic hybrid material is formed of an organic material (raw material of an organic component) and an inorganic material (raw material of an inorganic component), and the organic material and the inorganic material are composited at the nano level or the molecular level. The organic-inorganic hybrid material has, for example, a network-like crosslinked structure in which an inorganic material dispersed in an organic material and an organic material cause a reaction such as a polymerization reaction, and the inorganic component is highly dispersed in the organic component via a chemical bond. It has. Since the hard coat layer 38 is made of an organic-inorganic hybrid material, the interlayer adhesion between the protective film 36 and the hard coat layer 38 is improved. It is presumed that this is because the curing shrinkage of the hard coat layer 38 is suppressed by adding an inorganic component to the material forming the hard coat layer 38.

Examples of the raw material of the organic component forming the organic-inorganic hybrid material include a curable resin. Examples of the curable resin include acrylic resin, epoxy resin, urethane resin and the like. These may be used alone or in combination of two or more. Moreover, as a raw material of an inorganic component, a metal compound and the like can be mentioned. Examples of the metal compound include Si compounds, Ti compounds, Zr compounds and the like. These may be used alone or in combination of two or more. The metal compound is a compound containing an inorganic component such as Si, Ti, and Zr, and is composed of a compound that can be compounded by causing a reaction such as a polymerization reaction with a raw material of the organic component. More specific examples of the metal compound include organometallic compounds. Examples of the organometallic compound include a silane coupling agent, a metal alkoxide, a metal acylate, a metal chelate, and a silazane.

The pressure-sensitive adhesive layer 34 can be formed by applying a pressure-sensitive adhesive on the surfaces of the mask 22 and the thin film layer 13. The protective film 36 can be formed by arranging it on the surface of the formed pressure-sensitive adhesive layer 34 and applying pressure to adhere it to the pressure-sensitive adhesive layer 34. Then, the hard coat layer 38 can be formed by applying the material forming the hard coat layer 38 on the surface of the protective film 36 and performing drying, curing, and cross-linking treatment as necessary.

Next, other connection structures will be described. 8 and 9 show other connection structures.

The film antenna is the same as the film antenna 50 shown in FIG. Therefore, the description thereof will be omitted. In the film antenna 50, the metal wiring 42 extending from the connector 44 arranged on the outside of the hard coat layer 38 from the outside of the hard coat layer 38 to penetrate the substrate 12 penetrates the antenna pattern 16a which is an antenna element (antenna element). As a result, the metal wiring 42 is electrically connected to the antenna pattern 16a. A coaxial cable 46 is connected to the connector 44.

The film antenna according to the present invention can be suitably used as a thin antenna mounted on an electronic device such as a mobile communication terminal or a vehicle such as an automobile. Further, in the film antenna according to the present invention, the antenna pattern can be used as a conductive pattern other than the purpose of the antenna. Therefore, the film antenna according to the present invention is not limited to the film antenna, and can be applied to other applications requiring a conductive pattern. Other uses include applications that require conductivity and the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, although the mask 22 is included in each of the above embodiments, the mask 22 may be removed from the film antenna of the present invention.

Further, in the film antennas shown in FIGS. 5, 6 and 7, the non-conductive film was not removed as in the film antenna shown in FIG. 2, but in the film antennas shown in FIGS. 5, 6 and 7, FIG. 4 Similar to the film antenna shown in 1, the non-conductive film may be removed.

Further, in the film antennas shown in FIGS. 4, 5 and 6, similarly to the film antenna shown in FIG. 1, the adhesive layer 34, the protective film 36 and the hard coat layer 38 are not provided, but FIGS. Similarly to the film antenna shown in FIG. 7, the film antenna shown in 6 may also be provided with the adhesive layer 34, the protective film 36, and the hard coat layer 38. In the film antenna shown in FIG. 4, when the pressure-sensitive adhesive layer 34, the hard coat layer 38, or the like is provided, the conductive film which is a portion constituting the antenna pattern and the pressure-sensitive adhesive, the curable resin, or the portion which does not form the antenna pattern. A non-conductive material made of an organic-inorganic hybrid material is included in the same plane.

Further, the shape of the antenna pattern 16a is not particularly limited, and various antenna patterns can be used depending on the application.

Further, for example, in FIGS. 8 and 9, as a connection structure of the film antenna 50, a form in which the metal wiring 42 penetrates the antenna pattern 16a from the outside of the hard coat layer 38 is shown, but from the outside of the hard coat layer 38. The film antenna 50 may be connected by the metal wiring penetrating the antenna pattern 16a and another metal wiring penetrating the antenna pattern 16a from the outside of the substrate 12 (clipping).

Further, the other connection structures shown in FIGS. 8 and 9 and the connection structure by clipping may be applied to the film antennas 10 to 40. Further, the other connection structures shown in FIGS. 8 and 9 and the connection structure by clipping include a film antenna to which the surface protection layer 24 is applied to the film antennas 10 to 40 and an adhesive layer 32 to the film antennas 20 to 40. , The protective film 34 and the surface protective layer 24 may be applied to the film antenna.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

(Example 1)
<Manufacturing of film antenna>
Sn oxidation using a DC magnetron sputtering device on the surface opposite to the easy-adhesive layer of a 50 μm-thick polyethylene terephthalate film (“Cosmo Shine (registered trademark) A4300” manufactured by Toyo Spinning Co., Ltd.) in which an easy-adhesive layer is formed on one side. A first discontinuous film containing Sn oxide was formed by sputtering on a product (“SnOx (x <1)” manufactured by Toyoshima Seisakusho) (thickness 2 nm). Next, a metal thin film (thickness 10 nm) containing an Ag—Cu alloy was formed on the surface of the first discontinuous film by sputtering. Next, a second discontinuous film containing Sn oxide was formed on the surface of the metal thin film by sputtering using Sn oxide (“SnOx (x <1)” manufactured by Toyoshima Seisakusho) as a target (thickness 2 nm). .. Next, a mask material (acrylic resin, DIC "UVT Clear-EX80112") is placed at a position corresponding to a portion constituting the antenna pattern when viewed in the thickness direction so as to obtain the antenna pattern as shown in FIG. A mask was formed by coating, drying and UV curing. Next, oxygen plasma treatment was performed on the mask to oxidize the portion of the metal thin film not covered by the mask. As described above, the film antenna of Example 1 having the structure shown in FIG. 1 was produced.

(Example 2)
A 50 μm-thick polyethylene terephthalate film (“Cosmo Shine (registered trademark) A4300” manufactured by Toyo Spinning Co., Ltd.) with an easy-adhesive layer formed on one side is used on the opposite side of the easy-adhesive layer, using a microgravure coater, as shown below. A TiOx thin film (thickness 20 nm) was formed by applying a coating liquid for forming a TiOx thin film, drying the coating film at 100 ° C. for 80 seconds, and then irradiating with ultraviolet rays to cure the sol-gel. Next, on the surface of the formed TiOx thin film, as in Example 1, a first discontinuous film containing Sn oxide, a metal thin film containing an Ag—Cu alloy, and a second discontinuous film containing Sn oxide. Was formed into a film, and oxygen plasma treatment was performed in the same manner as in Example 1. From the above, the film antenna of Example 2 was produced.

<Adjustment of coating liquid for forming TiOx thin film>
A coating for forming a TiOx thin film by blending tetra-n-butoxytitanium tetramer (“B4” manufactured by Nippon Soda) and acetylacetone in a mixed solvent of n-butanol and isopropyl alcohol and mixing for 10 minutes using a stirrer. The solution was prepared. The composition of tetra-n-butoxytitanium tetramer / acetylacetone / n-butanol / isopropyl alcohol was 6.75% by mass / 3.38% by mass / 59.87% by mass / 30.00% by mass, respectively.

(Example 3)
A film antenna was produced in the same manner as in Example 1 except that the thicknesses of the first discontinuous film containing Sn oxide and the second discontinuous film containing Sn oxide were changed.

(Example 4)
At the time of film formation of the first discontinuous film and the second discontinuous film, a film antenna was produced in the same manner as in Example 1 except that the target was changed to metal Ti and Ti oxide was obtained by natural oxidation. ..

(Example 5)
At the time of forming the second discontinuous film, the target was changed to metal Ti, Ti oxide was obtained by natural oxidation, and the thickness of the first discontinuous film was changed in the same manner as in Example 3. A film antenna was manufactured.

(Example 6)
Metal Ti is targeted on the surface opposite to the easy-adhesive layer of a 50 μm-thick polyethylene terephthalate film (“Cosmo Shine (registered trademark) A4300” manufactured by Toyo Spinning Co., Ltd.) in which an easy-adhesive layer is formed on one side, and the metal is sputtered. A metal thin film (thickness 10 nm) containing Ti was formed. The surface of this metal thin film is passivated. Next, a mask material (acrylic resin, DIC "UVT Clear-EX80112") is placed at a position corresponding to a portion constituting the antenna pattern when viewed in the thickness direction so as to obtain the antenna pattern as shown in FIG. A mask was formed by coating, drying and UV curing. Next, oxygen plasma treatment was performed on the mask to oxidize the portion of the metal thin film not covered by the mask. From the above, a film antenna was manufactured.

(Example 7)
A film antenna was produced in the same manner as in Example 6 except that the target was changed to metal Cu.

(Comparative Example 1)
In sputtering targeting Sn oxide, a film antenna was produced in the same manner as in Example 1 except that the film thickness was changed.

The conditions for the oxygen plasma treatment are as follows.
Gas type: Oxygen pressure: 13 Pa
Microwave frequency: 2.45 GHz
Output power: 500W
Irradiation time: 10 sec

Using each of the produced film antennas, the antenna function, light transmission, adhesion, and weather resistance were evaluated.

(Antenna function)
We made a λ / 2 dipole antenna compatible with terrestrial digital broadcasting, connected the TV to the antenna, and confirmed whether reception was possible. Receivable was set as "○" and non-receivable was set as "x".

(Optical transparency)
The transmittance for each wavelength was measured with a spectrophotometer (“SolidSpec3700” manufactured by Shimadzu Corporation), and the visible light transmittance was calculated in accordance with JIS A5759.

(Adhesion)
A metal thin film was cut into a grid (25 squares) at 1 mm intervals with a cutter, and a peeling test was performed with cellophane tape.

(Weatherability)
A plate glass having a thickness of 3 mm was attached to the surface of the thin film layer of the produced film antenna via an acrylic adhesive sheet having a thickness of 25 μm (“5402” manufactured by Sekisui Chemical Co., Ltd.) to prepare a test piece 1. Using the test piece 1, a xenon lamp (output 160 W / m ² ) was irradiated from the glass side for 1000 hours (measurement wavelength 300 to 390 nm). The presence or absence of discoloration of the test piece was visually confirmed.

(Film thickness measurement)
The film thickness of each thin film layer was measured by observing the cross section of the test piece with a field emission electron microscope (HRTEM) (“JEM2001F” manufactured by JEOL Ltd.).

In Comparative Example 1, the film containing Sn oxide formed by sputtering targeting Sn oxide was too thick, and the film containing Sn oxide was a discontinuous film composed of metal oxide. It is not. Therefore, even if the oxygen plasma treatment was performed from above the mask, the portion of the metal thin film not covered with the mask was not oxidized. Therefore, in Comparative Example 1, the antenna pattern was not formed on the substrate. As a result, the film antenna of Comparative Example 1 does not have an antenna function.

On the other hand, in Examples 1 to 3, the film containing Sn oxide formed by sputtering targeting Sn oxide is sufficiently thin, so that the film containing Sn oxide is a metal oxide. It is a discontinuous film composed. Therefore, the portion of the metal thin film not covered with the mask was oxidized by the oxygen plasma treatment. Therefore, in Examples 1 to 3, an antenna pattern was formed on the substrate. As a result, the film antennas of Examples 1 to 3 have an antenna function.

In Examples 4 to 5, the film containing the Ti oxide formed by sputtering targeting the metal Ti is sufficiently thin, so that the film containing the Ti oxide is discontinuous composed of the metal oxide. It is a film. Therefore, the portion of the metal thin film not covered with the mask was oxidized by the oxygen plasma treatment. Therefore, in Examples 4 to 5, an antenna pattern was formed on the substrate. As a result, the film antennas of Examples 4 to 5 have an antenna function.

In Examples 6 to 7, a mask was formed on the surface of the metal thin film, and the portion of the metal thin film not covered with the mask was oxidized by the oxygen plasma treatment. Therefore, in Examples 6 to 7, an antenna pattern was formed on the substrate. As a result, the film antennas of Examples 6 to 7 have an antenna function.

Then, it was confirmed that the film antennas of Examples 1 to 7 were also excellent in light transmission, adhesion and weather resistance.

Although the examples of the present invention have been described above, the present invention is not limited to the above examples, and various modifications can be made without departing from the spirit of the present invention.

10, 20, 30, 40, 50 Film antenna 12 Substrate 13 Thin film layer 14 Discontinuous film 15 Metal thin film 16 Intermediate thin film 16a Part that constitutes the antenna pattern 16b Part that does not form the antenna pattern 17 Thin film layer 18 Discontinuous film 22 Mask 26 Wiring pattern 28 Feeding part 32 Metal oxide layer 34 Adhesive layer 36 Protective film 38 Hard coat layer 42 Metal wiring 44 Antenna 46 Coaxial cable

Claims (11)

On the surface of the substrate, there is a thin film layer in which the portion constituting the antenna pattern and the portion not constituting the antenna pattern are contained in the same plane.
The portion constituting the antenna pattern is made of a conductive film containing a metal.
A film antenna characterized in that a portion that does not form the antenna pattern is made of a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide. A thin film layer including a portion constituting the antenna pattern is provided on the surface of the substrate.
The portion constituting the antenna pattern is made of a conductive film containing a metal.
A film antenna characterized by having a discontinuous film made of a metal oxide on the surface of the thin film layer. The film antenna according to claim 1, wherein a discontinuous film made of a metal oxide is provided on the surface of the thin film layer. The film athena according to claim 2, wherein the thickness of the discontinuous film is 0.5 nm or more and 5.0 nm or less. A claim is characterized in that a mask covering the portion is arranged on the surface of the portion constituting the antenna pattern, and the portion is not covered with the mask on the surface of the portion not forming the antenna pattern. Item 4. The film antenna according to any one of Items 1 to 4. The film antenna according to any one of claims 1 to 5, wherein the conductive film contains at least one metal of silver, copper, titanium, a silver alloy, a copper alloy, and a titanium alloy. The film antenna according to any one of claims 2 to 6, wherein the discontinuous film contains an oxide of at least one metal of titanium, tin, tantalum, and zinc. A method for manufacturing a film antenna having an antenna pattern on the surface of a substrate.
The process of forming a metal thin film on the surface of the substrate,
The portion of the metal thin film that does not correspond to the antenna pattern is oxidized, nitrided, or carbonized to form a non-conductive film containing at least one of a metal oxide, a metal nitride, and a metal carbide, and the metal thin film is formed. A method for manufacturing a film antenna, which comprises a step of forming a conductive film containing a metal without oxidizing, nitriding, or carbonizing a portion corresponding to an antenna pattern. 8. The eighth aspect of the metal thin film, wherein a mask is placed on the surface of a portion of the metal thin film corresponding to the antenna pattern, and the portion of the metal thin film not corresponding to the antenna pattern is oxidized, nitrided, or carbonized. How to manufacture a film antenna. The method for manufacturing a film antenna according to claim 8 or 9, further comprising a step of removing the non-conductive film. The method for manufacturing a film antenna according to any one of claims 8 to 10, wherein oxidation, nitriding, or carbonization of a portion of the metal thin film that does not correspond to the antenna pattern is performed by plasma treatment.

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