JP2017175542A - antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna which integrates multiple antenna functions with good space efficiency and secures preferable invisibility.SOLUTION: An antenna 10 includes: a base material 20 formed into a sheet shape; a net-like first antenna layer 30 provided at the base material 20 and having light blocking effect and conductivity; and a net-like second antenna layer 40 provided at the base material 20 and having light blocking effect and conductivity. The first antenna layer 30 overlaps with the second antenna layer 40 when viewed in a normal direction of the base material 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna in which an antenna layer for receiving, transmitting or transmitting / receiving radio waves is provided on a base material.

  For example, in an automobile, it is installed on a windshield or the like as an antenna for receiving various radio waves such as TV radio waves and FM radio waves, and radio waves related to position coordinate information from GPS (global positioning system) satellites used in car navigation systems. A film antenna is known. A general film antenna is configured by providing an antenna layer made of a metal foil or the like on a transparent substrate such as a transparent polyester film. In such a film antenna, the antenna layer is opaque. Therefore, the antenna layer is in a state where it can be visually observed, although it does not significantly disturb the field of view. On the other hand, an antenna that improves invisibility by forming the antenna layer with a transparent ITO film (indium oxide film) is also known.

  A film antenna having an opaque antenna layer made of a metal foil or the like has good conductivity, but it is difficult to use it appropriately in applications where invisibility is strongly required. Therefore, the application range is restricted. For example, when it is provided on the screen of a display panel of a mobile phone, the visibility is remarkably impaired, making application difficult. On the other hand, when an ITO film is used, it can be applied to a display panel or the like. However, since the conductivity of the ITO film is generally inferior to that of metal, if the transparency is to be secured at a general several tens of nanometers, a situation in which the performance as an antenna cannot be sufficiently obtained may occur. Therefore, even when the ITO film is used, there is a problem of limitation of the application range. In addition, since the ITO thin film is more fragile than the metal foil, there is a problem that cracks and breaks are likely to occur when deformation is applied during the manufacturing process.

  In view of the above problems, the present inventors have previously proposed an antenna in which an antenna layer provided on a transparent substrate is formed in a mesh shape (see Patent Document 1 and Patent Document 2). According to this antenna, good invisibility and conductivity can be ensured. Such a so-called transparent antenna is considered to be able to further improve the quality by applying an invisibility technique or the like in the mesh electrode of the touch panel.

JP 2011-66610 A JP 2011-66691 A

  By the way, there is a case where a function of transmitting and receiving a plurality of radio waves having different frequencies is desired particularly in an automobile or a mobile phone. In this case, it is preferable to aggregate a plurality of antenna functions in a narrow area.

  The present invention has been made in consideration of the above-described points, and an object of the present invention is to provide an antenna that can secure a suitable invisibility while aggregating a plurality of antenna functions with high space efficiency.

The antenna of the present invention
A base material formed into a sheet,
A mesh-shaped first antenna layer provided on the base material and having light shielding properties and conductivity;
A mesh-like second antenna layer provided on the base material and having light shielding properties and conductivity;
When viewed from the normal direction of the base material, the first antenna layer overlaps the second antenna layer.

  In the antenna according to the present invention, the first antenna layer includes a plurality of first antenna conductors arranged in a mesh pattern on the base material, and a plurality of first antenna opening regions are defined by the plurality of first antenna conductors. The second antenna layer may include a plurality of second antenna conductors arranged in a mesh pattern on the base material, and a plurality of second antenna opening regions may be defined by the plurality of second antenna conductors. .

In the antenna according to the present invention, the first antenna layer has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the first antenna opening region having a constant shape intersects. The antenna layer has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the second antenna opening region of a constant shape intersects, and the first antenna layer and the second antenna layer are The mesh pattern shapes are arranged so as to be similar to each other and in the same direction, and each pitch of the first antenna opening areas in each direction in which the first antenna opening areas are arranged is determined by the second antenna opening area. May be an integral multiple of each pitch of the second antenna aperture region in each direction in which the antennas are arranged.
Further, when viewed from the normal direction of the base material, the first antenna conductor that defines the first antenna opening region includes at least two or more second antennas that define the second antenna opening region. The conductive wire may overlap and overlap with a linear portion that is connected in a straight line.
In addition, the first antenna layer has a mesh pattern shape arranged at a constant pitch in each of two directions where the first antenna opening area of a constant rectangular shape intersects, and the second antenna layer is The second antenna opening region having a fixed rectangular shape may have a mesh pattern shape arranged at a fixed pitch in each of two directions intersecting each other.

In the antenna according to the present invention, an average value m of the area of the first antenna opening area in the first antenna layer and a standard deviation σ of the area of the first antenna opening area may satisfy the following expression.
3 ≦ 3σ / m × 100 ≦ 20

In the antenna according to the present invention, an average value m of the area of the second antenna opening area in the second antenna layer and a standard deviation σ of the area of the second antenna opening area may satisfy the following expression.
3 ≦ 3σ / m × 100 ≦ 20

  In the antenna according to the present invention, at least one of the first antenna layer and the second antenna layer is a main body layer made of a metal material, and is opposite to the base material side and / or the base material with respect to the main body layer. And a low reflection layer made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface, the thickness of the low reflection layer is 10 nm to 60 nm, The reflection Y value may be 30% or less.

  In the antenna according to the present invention, the substrate may be transparent.

In the antenna according to the present invention, the first antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other through the transparent adhesive layer. 1 ratio of the total light reflectance was measured in conformity with JIS Z 8722 of the transparent adhesive layer side surface of the antenna layer _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R SCI) is 0. It may be 4 or less.

In the antenna according to the present invention, the second antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other through the transparent adhesive layer. the ratio of the total light reflectance was measured in conformity with JIS Z 8722 of the transparent adhesive layer side surface of the second antenna layer _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R SCI) is 0. It may be 4 or less.

  In the antenna according to the present invention, the base material may include a first base material on which the first antenna layer is provided and a second base material on which the second antenna layer is provided.

  In the antenna according to the present invention, the first base material and the second base material may be transparent.

In the antenna according to the present invention, the first antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other of the first base material via a transparent adhesive layer, diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the first antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is It may be 0.4 or less.

In the antenna according to the present invention, the second antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other of the second base material via a transparent adhesive layer, diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the second antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is It may be 0.4 or less.

  According to the present invention, it is possible to secure suitable invisibility while aggregating a plurality of antenna functions in a space efficient manner.

FIG. 1 is a plan view of an antenna according to an embodiment of the present invention. FIG. 2 is an enlarged view of an example of a region indicated by II in FIG. 3 is a cross-sectional view of the antenna taken along line III-III in FIG. FIG. 4 is a diagram showing a mobile phone to which the antenna shown in FIG. 1 is applied. FIG. 5 is a diagram showing an automobile to which the antenna shown in FIG. 1 is applied. FIG. 6 is a diagram showing a building to which the antenna shown in FIG. 1 is applied. FIG. 7 is a diagram showing an RFID tag to which the antenna shown in FIG. 1 is applied. FIG. 8 is a view corresponding to the cross-sectional view of the antenna of FIG. 3, and is a cross-sectional view of the antenna in a modified example. FIG. 9 is a plan view of an antenna according to another modification of the present invention. FIG. 10 is an enlarged view of an example of a region indicated by X in FIG. 11 is a cross-sectional view of the antenna along the line XI-XI in FIG. FIG. 12 is a plan view of an antenna layer of an antenna according to still another modified example of the present invention. FIG. 13 is an enlarged view of FIG. FIG. 14 is a diagram showing a general image display mechanism.

  Embodiments of the present invention will be described below with reference to the drawings.

  In this specification, terms such as “layer”, “sheet”, and “film” are not distinguished from each other based only on the difference in designation. For example, the “layer” is a concept including a member that can be called a sheet or a film. Furthermore, as used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “parallel” and “orthogonal”, length and angle values, and the like are bound to a strict meaning. Therefore, it should be interpreted including the extent to which similar functions can be expected. In the drawings referred to in this embodiment, the same portions or portions having similar functions are denoted by the same reference symbols or similar symbols, and repeated description thereof may be omitted. In addition, the dimensional ratio in the drawing may be different from the actual ratio for convenience of explanation, or a part of the configuration may be omitted from the drawing.

(Schematic configuration of antenna)
1 is a plan view of an antenna 10 according to an embodiment of the present invention, FIG. 2 is an enlarged view of a region indicated by II in FIG. 1, and FIG. 3 is taken along line III-III in FIG. It is sectional drawing. As shown in FIGS. 1 to 3, the antenna 10 according to the present embodiment is a so-called transparent antenna, which is formed in a sheet shape and is provided on the transparent base material 20, and is provided on the base material 20. A pair of mesh-like first antenna layers 30 having a property and a pair of mesh-like second antenna layers 40 provided on the base material 20 and having light shielding properties and conductivity.

  The illustrated antenna 10 is configured as a half-wave dipole antenna capable of transmitting a plurality of radio waves having different frequencies as an example. The base member 20 is provided with a first extraction electrode portion 13 </ b> A that is electrically connected to a part of the outer peripheral portion of each of the pair of first antenna layers 30 and extends outward from the first antenna layer 30. Each first antenna layer 30 is electrically connected to a common first feeding part 7A via a corresponding first extraction electrode part 13A and external wiring. Similarly, the base material 20 is provided with a second extraction electrode portion 13B that is electrically connected to a part of the outer peripheral portion of each of the pair of second antenna layers 40 and extends outward from the second antenna layer 40. Yes. Each second antenna layer 40 is electrically connected to a common second feeding part 7B via a corresponding second extraction electrode part 13B and external wiring.

  Each of the power supply units 7A and 7B corresponds to an AC power supply that supplies a signal to be transmitted as an AC current (voltage), and includes an oscillation circuit, a modulation circuit, an amplification circuit, and the like. When the antenna 10 is configured as a receiving half-wave dipole antenna, a receiving circuit including a tuning circuit, an amplifier circuit, a frequency conversion circuit, a demodulation (detection) circuit, and the like is connected instead of the power feeding units 7A and 7B. .

  In the half-wave dipole antenna, the length (L11 + L12) of the first antenna layer 30 and the length (L21 + L22) of the second antenna layer 40 shown in FIG. 1 are ½ times the wavelength of the radio wave to be transmitted or received. When the frequency of the radio wave transmitted or received by the first antenna layer 30 is 2.45 GHz, the wavelength is about 122.4 mm, so the length (L11 + L12) of the first antenna layer 30 is about 61.2 mm. The length of one first antenna layer 30 is about 30.6 mm. Since the second antenna layer 30 transmits or receives radio waves having a frequency different from that of the first antenna layer 30, the length (L21 + L22) of the second antenna layer 40 is the length (L11 + L12) of the first antenna layer 30. Is different. In the example shown in FIG. 1, the length (L21 + L22) of the second antenna layer 40 is longer than the length (L11 + L12) of the first antenna layer 30. In addition, although the dimension of the width | variety E1 of the 1st antenna layer 30 and the width | variety E2 of the 2nd antenna layer 40 is suitably set by the resistance of the desired antenna layers 30 and 40, for example, it may be about 5-50 mm. Good. In the example shown in FIG. 1, the width E <b> 2 of the second antenna layer 40 is larger than the width E <b> 1 of the first antenna layer 30.

(Layer structure)
The layer configuration of the antenna 10 of the present embodiment will be described with reference to FIG. In the present embodiment, the antenna 10 is composed of a single-layer member having a first surface 20a and a second surface 20b with which the base material 20 faces each other. The first antenna layer 30 and the first extraction electrode portion 13A are provided on the first surface 20a of the base material 20 via the transparent adhesive layer 12, and the transparent adhesive is provided on the second surface 20b of the base material 20. A second antenna layer 40 and a second extraction electrode portion 13B are provided via the layer 12. That is, the first antenna layer 30 and the second antenna layer 40 are provided at different positions in the normal direction of the substrate 20. In the present embodiment, the first antenna layer 30 includes a main body layer 31a made of a metal material, and a low reflection layer 31b made of copper nitride laminated on the side opposite to the base material 20 side with respect to the main body layer 31a. , Including. Similarly, the second antenna layer 40 includes a main body layer 41a made of a metal material, and a low reflection layer 41b made of copper nitride laminated on the side opposite to the base material 20 side with respect to the main body layer 41a. Yes.

  Moreover, in this Embodiment, in the 1st antenna layer 30, the surface by the side of the base material 20 (surface by the side of the transparent adhesive layer 12) is the smooth surface 30a with low light scattering property, and what is the base material 20 side? The opposite surface is a non-smooth surface 30b. Similarly, in the second antenna layer 40, the surface on the base material 20 side (the surface on the transparent adhesive layer 12 side) is a smooth surface 40a having a low light scattering property, and is a surface opposite to the base material 20 side. Is a non-smooth surface 40b. Here, the smooth surface in the present embodiment means “mirror surface”, and the non-smooth surface means “rough surface”. In the metal foil manufacturer, the surface of the outer surface (front and back surfaces) of the metal foil is subjected to physical or chemical treatment that increases the degree of unevenness on the surface, and the surface on the side where the degree of unevenness is relatively increased. It is called “rough surface” (otherwise, “roughened surface” or “matte surface”). On the other hand, the surface on the other side is referred to as “mirror surface” (also referred to as “smooth surface”, “glossy surface”, or “mirror surface”). “Rough surface” and “mirror surface” as used in the present embodiment are defined as the same terms as “rough surface” and “mirror surface” as described by the metal foil manufacturer as described above.

  In the example shown in FIG. 3, the first antenna layer 30 and the second antenna layer 40 are exposed to the outside, but the first antenna layer 30 and the second antenna layer 40 are transparent resin layers as necessary. It may be covered. Such a resin layer can be formed, for example, by applying a liquid composition containing a resin to the uneven surface formed by the first antenna layer 30 and the second antenna layer 40 on the base material 20. The liquid composition is not particularly limited as long as it contains a transparent resin, and a known resin may be appropriately employed.

  In the present embodiment, the base material 20 is a single layer, but the base material 20 may have a multilayer structure including a plurality of layers. The first antenna layer 30 and the second antenna layer 40 have a multilayer structure, but may have a single layer structure. As will be described later, the low reflection layers 31b and 41b are provided to reduce the reflectance, but a blackening layer may be used instead of the low reflection layers 31b and 41b. Further, the surface of the first antenna layer 30 and the second antenna layer 40 on the base material 20 side is a smooth surface, and the opposite surfaces are non-smooth surfaces, but both surfaces are smooth surfaces. The surfaces on both sides may be non-smooth surfaces. Hereinafter, each component of the antenna 10 will be described in detail.

(Base material)
As the base material 20, for example, a sheet or plate made of an organic material such as resin or an inorganic material such as glass is used. When it is strongly desired to secure a field of view in the antenna 10, the higher the transparency of the base material 20, the better. In this case, it is desirable that the base material 20 has a light transmittance such that the light transmittance in the visible light region of 380 to 780 nm is 70% or more, more preferably 80% or more. The light transmittance can be measured using a spectrophotometer (for example, UV-3100PC manufactured by Shimadzu Corporation) and a value measured in the air at room temperature. Further, the haze value of the substrate 20 in accordance with JIS K 7105-1981 is preferably 10% or less, more preferably 2.0% or less, and particularly preferably 1.0% or less. .

  Examples of the resin used as the material of the substrate 20 include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, terephthalic acid-isophthalic acid-ethylene glycol copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, and the like. Polyester resins such as polyester resins, polyamide resins such as nylon 6, polyolefin resins such as polypropylene, polymethylpentene and cycloolefin polymers, acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymers, Examples thereof include cellulose resins such as triacetyl cellulose, imide resins, and polycarbonate resins. These resins may be used alone or as a plurality of types of mixed resins (including polymer alloys). When the substrate 2 is a resin film, a uniaxially stretched or biaxially stretched film is more preferable in terms of mechanical strength. In addition, additives such as a filler, a plasticizer, and an antistatic agent may be appropriately added to these resins as necessary.

  Examples of the glass constituting the substrate 20 include soda glass, potash glass, borosilicate glass, and quartz glass. Usually, glass is used in the form of a thick plate.

  The thickness of the substrate 20 is not particularly limited, but is usually 12 to 5000 μm, preferably 50 to 500 μm, more preferably 50 to 200 μm in the case of a film, and 500 to 3000 μm in the case of a plate. Within such a thickness range, the mechanical strength is sufficient, warping, loosening, breakage, etc. are prevented, and it is easy to supply and process in a continuous belt shape. In addition, as the base material 20, what consists of a flexible resin film or board is especially preferable at the point that manufacturing process aptitude is favorable and a weight and a price can also be reduced. Moreover, in the base material 20 which consists of resin films etc., well-known, such as corona discharge treatment, plasma treatment, ozone treatment, flame treatment, primer treatment, pre-heat treatment, dust removal treatment, vapor deposition treatment, alkali treatment, etc. The easy adhesion treatment may be performed. The base material 20 may be colored transparent or opaque.

(Transparent adhesive layer)
The transparent adhesive layer 12 can bond the first antenna layer 30 and the second antenna layer 40 to the base material 20 and can be of any kind as long as it has sufficient transparency in the present embodiment. Is not particularly limited. However, in the present embodiment, after the first antenna layer 30 and the second antenna layer 40 are bonded to the metal foil and the base material 20 via the transparent adhesive layer 12, the metal foil is etched into a pattern shape. Therefore, it is preferable that the transparent adhesive layer 12 has etching resistance. Specific examples include polyurethane resins such as polyurethane ester resins and two-component curable urethane resins, acrylic resins, polyester resins, and epoxy resins. The transparent adhesive layer 12 may be an ultraviolet curable type or a thermosetting type. In particular, from the viewpoint of adhesion to the base material 20, a polyurethane resin, an acrylic resin, a polyester resin, particularly a two-component curable urethane resin is preferable.

  The film thickness of the transparent adhesive layer 12 is preferably in the range of 0.5 μm to 50 μm, particularly in the range of 1 μm to 20 μm. Thereby, the base material 20 and the 1st antenna layer 30 and the 2nd antenna layer 40 can be adhere | attached firmly, and a base material is formed in the case of the etching which forms the 1st antenna layer 30 and the 2nd antenna layer 40 This is because 20 can be prevented from being affected by an etching solution such as iron oxide. Moreover, it is preferable that the refractive index of the transparent adhesive layer 12 exists in the range of 1.41-1.59 from a viewpoint of interface reflection reduction by the refractive index difference with the base material 20, and also 1.48-1. It is preferable to be within the range of 52.

(First antenna layer)
Next, the first antenna layer 30 will be described with reference to FIG. The first antenna layer 30 includes a plurality of first antenna conductors 31 arranged in a mesh pattern on the first surface 20 a of the base material 20, and the plurality of first antenna opening regions 32 are formed by the plurality of first antenna conductors 31. It is defined. In the present embodiment, the first antenna conducting wire 31 extends between two branch points 33 at a plurality of branch points 33 scattered in the first antenna layer 30 to define a first antenna opening region 32. Means the part.

The first antenna layer 30 in the present embodiment has a mesh pattern shape in which the first antenna opening regions 32 having a certain rectangular shape are spread without gaps. Specifically, the first antenna opening regions 32 are arranged at a constant pitch in a first direction d ₁ and a second direction d ₂ that intersect each other. That is, the first antenna aperture area 32, a first antenna conductor 31 a plurality of which are arranged at a constant pitch P11 in the direction of each orthogonal linearly extending and first direction d ₁ in the first direction d _1, each Is defined by a plurality of first antenna conductors 31 that extend linearly in the second direction d _{2 and} are arranged at a constant pitch P 12 that is the same as the constant pitch P 11 in a direction orthogonal to the second direction d ₂ . . As a result, the first antenna opening regions 32 included in the illustrated first antenna layer 30 are all formed in the same quadrangular shape, in particular, a rhombus shape. Note that the above-described mesh pattern shape means a symbol determined by the shape, pitch, size, and the like of the opening region in the present embodiment.

  As shown in FIG. 1, in the present embodiment, each of the pair of first antenna layers 30 is formed in a rectangular shape as indicated by the first contour line FL1, and is disposed so as to face each other. ing. Here, as shown in FIG. 1 and FIG. 2, the contour line FL1 is a line defined by connecting ends of the plurality of first antenna conductors 31 located on the outermost periphery in the first antenna layer 30 with straight lines. More specifically, it means a line defined by sequentially connecting adjacent end portions of the end portions of the plurality of first antenna conducting wires 31 located on the outermost periphery in a straight line. In the present embodiment, the first antenna layer 30 has a rectangular shape, but such a shape is not particularly limited as long as a desired radio wave can be transmitted or received. Or a meandering shape.

  Further, as described above, the first antenna layer 30 (first antenna conductive wire 31) in the present embodiment has the main body layer 31a and the low reflection layer 31b made of copper nitride, and the low reflection layer. Since 31b is copper nitride, it contains copper as a main component, but the main body layer 31a also contains copper as a main component. Therefore, the first antenna layer 30 generally contains copper as a main component. However, the material of the first antenna conductor 31 is not limited to copper, and may be formed of, for example, gold, silver, aluminum, or the like.

  The thickness of the first antenna layer 30 may be appropriately selected from the viewpoints of high conductivity, processability, mechanical strength, etc. depending on the material. Specifically, when the main component is copper, the thickness is 0.1 μm or more and 20 μm or less is preferable, and 0.5 μm or more and 5 μm or less is more preferable. The thickness of the second antenna layer 30 is more preferably 1 μm or more and 3 μm or less. When the thickness is small, the conductivity and mechanical strength are lowered, and when the thickness is thick, the workability is lowered.

  Further, in the present embodiment, the first antenna layer 30 is formed in a mesh pattern shape in which the rectangular first antenna opening regions 32 are regularly arranged, but the mesh pattern shape of the first antenna layer 30 is It may be a pattern shape such as a honeycomb pattern shape, a square lattice shape, a rectangular lattice shape, a triangular lattice shape, or a Voronoi mesh, in which irregularly shaped opening regions are irregularly defined.

(Second antenna layer)
Next, the second antenna layer 40 will be described with reference to FIG. Similarly to the first antenna layer 30, the second antenna layer 40 includes a plurality of second antenna conductors 41 arranged in a mesh pattern on the second surface 20 b of the substrate 20, and the plurality of second antenna conductors 41 A plurality of second antenna opening regions 42 are defined. The second antenna conducting wire 41 means a linear portion that extends between two branch points 43 at a plurality of branch points 43 scattered in the second antenna layer 40 to define the second antenna opening region 42. Yes.

  As shown in FIGS. 1 and 2, the second antenna layer 40 in the present embodiment overlaps with the first antenna layer 30 when viewed from the normal direction of the substrate 20. Details of this will be described later.

As shown in FIG. 2, the second antenna layer 40 in the present embodiment has a mesh pattern shape in which second antenna opening regions 42 having a fixed rectangular shape are spread without gaps. Accordingly, the second antenna opening regions 42 are arranged at a constant pitch in the first direction d ₁ and the second direction d ₂ that intersect each other. That is, the second antenna aperture region 42 includes a plurality of second antenna conductor 41 which are arranged at a predetermined pitch P21 in the direction of each orthogonal linearly extending and first direction d ₁ in the first direction d _1, each are defined but the plurality of second antenna conductor 41 which are arranged at a constant pitch P21 of the same constant pitch P22 in the direction orthogonal to the extending and the second direction d ₂ linearly in the second direction d _2, by . As a result, the second antenna opening regions 42 included in the illustrated second antenna layer 40 are all formed in the same quadrangular shape, in particular, a rhombus shape.

  As shown in FIG. 1, in the present embodiment, each of the pair of second antenna layers 40 is formed to have a rectangular external shape as shown by the second contour line FL2, and are arranged to face each other. ing. Here, as shown in FIGS. 1 and 2, the contour line FL2 is a line defined by connecting the ends of a plurality of second antenna conductors 41 located on the outermost periphery in the second antenna layer 40 with straight lines. More specifically, it means a line defined by sequentially connecting adjacent end portions of the end portions of the plurality of second antenna conducting wires 41 located on the outermost periphery in a straight line. In the present embodiment, the second antenna layer 40 has a rectangular shape, but such a shape is not particularly limited as long as a desired radio wave can be transmitted or received. Or a meandering shape.

As described above, the second antenna layer 40 (second antenna conductor 41) in the present embodiment also includes the main body layer 41a and the low reflection layer 41b made of copper nitride, and the low reflection layer 41b. Since copper is copper nitride, it contains copper as a main component, but the main body layer 41a also contains copper as a main component. Therefore, the second antenna layer 40 contains copper as a main component as a whole. In addition, the material of the 2nd antenna conducting wire 41 is not restricted to copper, For example, you may form from gold | metal | money, silver, aluminum, etc.
In addition, with respect to a portion where the first antenna layer and the second antenna layer overlap in plan view, in order to reinforce the insulation between the first antenna layer and the second antenna layer, the opposing surfaces of both antenna layers The layer in the vicinity of the surface of at least one or both of these may be formed partially or entirely with an insulator such as a resin.
In the case of forming a layer made of an insulator such as the resin, it is the same as the metal layer using a plate printing method such as silk screen printing, intaglio printing, flexographic printing, or a plateless printing method such as ink jet printing. The width | variety of this, or the process which can form width and thickness can be used.

  The thickness of the second antenna layer 40 may be appropriately selected according to the material from the viewpoints of processability, mechanical strength, high conductivity, etc., but increases the invisibility by suppressing variations in light transmittance. For this purpose, the thickness is preferably the same as that of the first antenna layer 30. Therefore, the thickness of the second antenna layer 40 is preferably 0.1 μm or more and 20 μm or less, and more preferably 0.5 μm or more and 5 μm or less. The thickness of the second antenna layer 40 is more preferably 1 μm or more and 3 μm or less.

  In the present embodiment, the second antenna layer 40 is formed in a mesh pattern shape in which square-shaped second antenna opening regions 42 are regularly arranged, but the mesh pattern shape of the second antenna layer 40 is It may be a pattern shape such as a honeycomb pattern shape, a square lattice shape, a rectangular lattice shape, a triangular lattice shape, or a Voronoi mesh, in which irregularly shaped opening regions are irregularly defined.

(Relationship between the first antenna layer and the second antenna layer)
Hereinafter, the relationship between the first antenna layer 30 and the second antenna layer 40 will be described in detail. As shown in FIG. 1, the region defined by the first contour line FL1 overlaps the region defined by the second contour line FL2, and when viewed from the normal direction of the base material 20, The first antenna layer 30 overlaps the second antenna layer 40. In the example shown in FIG. 1, the entire area of the first antenna layer 30 overlaps with the second antenna layer 40 and the second antenna layer 40 is formed in a wider area than the first antenna layer 30, so that the second antenna layer Reference numeral 40 denotes a position surrounding the entire outer peripheral portion of the pair of first antenna layers 30. In the illustrated example, the first antenna layer 30 and the second antenna layer 40 are parallel to each other.

In the present embodiment, the first antenna layer 30 is constant in each of the first direction d ₁ and the second direction d ₂ , which are two directions where the first antenna opening area 32 having a constant rectangular shape intersects. The first direction d ₁ and the second direction have a mesh pattern shape arranged at the pitches P11 and P12, and the second antenna layer 40 is two directions in which the second antenna opening region 42 having a certain rectangular shape intersects. Each of d ₂ has a mesh pattern shape arranged at a constant pitch P21, P22, and the first antenna layer 30 and the second antenna layer 40 are similar in mesh pattern shape to each other and in the same direction. Is arranged.

In this embodiment, where each pitch P11, P12 of the first antenna aperture area 32 in each of the first direction d ₁ and the second direction d ₂ of the first antenna aperture region 32 is arranged is, corresponding, first 2 an integral multiple of the pitch P21, P22 of the second antenna aperture region 42 in the antenna aperture region 42 each of the first direction _{d 1} and the second direction _{d 2} arranged, in particular is twice. As is clear from FIG. 2, when viewed from the normal direction of the base material 10, the first antenna conductor 31 that defines the first antenna opening region 32 has at least the second antenna opening region 42. Two or more (two in this example) second antenna conductors 41 coincide with and overlap the linear portions that are connected in a straight line. According to such an arrangement, in the portion where the first antenna layer 30 and the second antenna layer 40 overlap, the antenna layer (in this example, the first antenna layer with the finer eye) when viewed from the normal direction of the substrate 10. 2) The mesh pattern shape of the antenna layer 40) appears on the appearance, and the invisibility depending on the smaller antenna layer is obtained, so that the invisibility of the entire antenna 1 is suppressed from being lowered by the overlapping of the plurality of antenna layers. The

  Note that the pitches P11 and P12 of the first antenna opening region 32 are not limited to twice the pitches P21 and P22 of the second antenna opening region 42, and may be viewed from the normal direction of the substrate 20 as long as they are integer multiples. In this case, the first antenna conductor 31 can be made to coincide with the second antenna conductor 41 as described above, and it is possible to suppress a decrease in invisibility.

  In addition, the first antenna layer 30 in this example has a mesh pattern shape arranged at a constant pitch in each of two directions where the first antenna opening area 32 having a constant square shape intersects, and the second antenna The layer 40 has a mesh pattern shape arranged at a constant pitch in each of two directions where the second antenna opening area 42 having a constant rectangular shape intersects. However, instead of this aspect, the first antenna layer 30 has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the first antenna opening regions 32 having a constant shape such as a triangle intersect. You may have. Similarly, the second antenna layer 40 may have a mesh pattern shape arranged at a constant pitch in each of two or more directions where the second antenna opening area 42 having a constant shape such as a triangle intersects. Good. Also in this aspect, the first antenna layer 30 and the second antenna layer 40 are arranged so that the mesh pattern shapes are similar to each other and in the same direction, and in each direction in which the first antenna opening regions 32 are arranged. Each pitch of the first antenna opening area 32 may be an integral multiple of each pitch of the second antenna opening area 42 in each direction in which the second antenna opening area 42 is arranged.

  In the present embodiment, as described above, the entire area of the first antenna layer 30 overlaps with the second antenna layer 40. More specifically, the second antenna layer 40 has an outer peripheral portion of the first antenna layer 30. It is located outside, especially surrounding the whole area. When an antenna having a mesh-like antenna layer is applied to an actual product, the antenna layer is assumed to be installed locally on, for example, a part of a windshield or a part of a display of a mobile phone. The The inventor of the present invention has found that the problem that the antenna layer becomes easy to be visually recognized due to the local installation mode arises in earnest research premised on such installation mode peculiar to the antenna. Then, in order to solve this problem, the idea was to make the antenna layer invisible. As described above, when the second antenna layer 40 is located outside the outer peripheral portion of the pair of first antenna layers 30, particularly when located so as to surround the entire area, the second antenna layer 40 causes the first antenna layer 30 to be surrounded by the second antenna layer 40. Does not appear to be locally installed, and the first antenna layer 30 becomes inconspicuous. Thereby, the invisibility of the 1st antenna layer 30 can be raised easily.

(Main layer and low reflection layer in the first antenna layer and the second antenna layer)
As described above, in the present embodiment, even if the first antenna layer 30 and the second antenna layer 40 are overlapped, a device that does not reduce the invisibility is made, but in the present embodiment, In addition, the above-described main body layers 31a and 41a and low reflection layers 31b and 41b have been devised to further increase invisibility and improve visibility in the field of view. Hereinafter, the main body layers 31a and 41a and the low reflection layers 31b and 41b will be described. In this example, in the 1st antenna layer 30 and the 2nd antenna layer 40, the structure of the main body layer 31a and the main body layer 41a is the same, and the structure of the low reflection layer 31b and the low reflection layer 41b is the same. . Therefore, hereinafter, the main body layer 31a and the main body layer 41a will be described together, and the low reflection layer 31b and the low reflection layer 41b will be described together.

  Specifically, first, the main body layers 31a and 41a are layers for mainly ensuring conductivity, and more specifically within a range of 0.5 μm to 5 μm so that the thickness thereof is, for example, 20 μm or less. It is configured as follows. Accordingly, it is possible to suppress an increase in the thickness of the first antenna lead 31 or the second antenna lead 41 as a whole, and external light or video light (display installation on the side surface of the first antenna lead 31 or the second antenna lead 41). Can be prevented from being reflected. Thereby, the improvement of invisibility and the improvement of visibility are achieved.

As described above, reducing the thickness of the main body layers 31a and 41a can obtain the effect of improving the invisibility and improving the visibility, while the electric resistance value of the first antenna lead 31 or the second antenna lead 41 is low. It can lead to becoming bigger. It is not desirable for the first antenna lead 31 and the second antenna lead 41 to have an excessively large resistance. Therefore, in the present embodiment, a metal material having a specific resistance equal to or lower than a desired value is used as a material constituting the main body layers 31a and 41a. For example, the specific resistance is 4.0 × 10 ^−6. Metal materials that are (Ωm) or less are used. Thereby, the electrical resistance values of the first antenna conductor 31 and the second antenna conductor 41 can be sufficiently reduced. For example, the sheet resistance values of the main body layers 31a and 41a can be set to 0.3Ω / □ or less. As a metal material having a specific resistance of 4.0 × 10 ⁻⁶ (Ωm) or less for constituting the main body layers 31a and 41a, for example, a metal such as gold, silver, copper, and aluminum is 90% by weight or more. The containing material (metal simple substance, metal alloy, etc.) can be used. In the present embodiment, a material containing 99% by weight of copper is used as the main body layers 31a and 41a. In the present embodiment, the main body layers 31 a and 41 a are made of a copper foil (copper thin film) laminated on the base material 20 via the transparent adhesive layer 12.

  On the other hand, metal materials such as copper have high conductivity but exhibit a metallic luster. For this reason, when an untreated metal material is used as the first antenna conductor 31 or the second antenna conductor 41, the visibility is hindered by the metallic luster of the first antenna conductor 31 or the second antenna conductor 41. In particular, since copper exhibits a reddish color peculiar to copper, it is more conspicuous than other metal materials such as silver, and this impedes visibility.

  In order to reduce such metallic luster peculiar to copper, for example, the conductive wire is oxidized to form a blackening treatment layer made of copper oxide on the surface of the conductive wire, thereby blackening (blackening) the surface of the conductive wire. Technology is known. However, the blackening treatment layer formed by the blackening treatment needs to have a certain thickness. Specifically, although it is a document related to the touch panel technology, for example, JP 2012-79238 A discloses a range of 0.2 μm or more and 2 μm or less as a preferable thickness of the blackening treatment layer. Further, a value of 2 μm is mainly adopted as the thickness of the conducting wire. In the conductive wire in which the blackening layer is formed in this way, reflection not to be ignored occurs not only on the surface of the conductive wire but also on the side surface of the conductive wire, or the image light from the display device is hindered by the side surface of the conductive wire. It is possible that

  Therefore, the present inventor does not blacken the main body layers 31a and 41a in the present embodiment, but suppresses metallic luster on the surfaces of the main body layers 31a and 41a as compared with the main body layers 31a and 41a. Further, thin low reflection layers 31b and 41b are provided. As a result, the metallic luster of the first antenna conductor 31 or the second antenna conductor 41 is reduced. Specifically, the low reflection layers 31b and 41b are layers made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface. The film thickness of the low reflection layers 31b and 41b is in the range of 10 nm to 60 nm, for example, 40 nm. The reflection Y value (also referred to as luminous reflectance) of the low reflection layers 31b and 41b is 30% or less, and preferably 27% or less. Here, the reflection Y value is a value according to the provisions of JIS Z 8722-1982, and means a reflectance with respect to light having a wavelength of around 550 nm.

  Generally, when the surface of a layer made of copper nitride is exposed to the atmosphere, the surface of the layer made of copper nitride may contain oxygen atoms by reacting with oxygen in the atmosphere (natural oxidation). However, according to the knowledge of the present inventors, the copper nitride that can be naturally oxidized in the copper nitride layer is copper nitride at a depth of about 0.1 nm from the surface. Therefore, when a layer made of copper nitride contains oxygen atoms at a depth of 5 nm or more from the surface, the oxygen atoms are not oxygen atoms derived from the natural oxidation of the surface, but from copper nitride at the time of film formation, for example. It can be considered that oxygen atoms are intentionally added to the layer. That is, the layer made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface means a layer made of copper nitride intentionally added with oxygen atoms, although the method for adding oxygen atoms is not particularly limited. . Note that the expression “a layer made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface” means that oxygen atoms are contained at a depth of 5 nm or more from the surface and oxygen atoms are also contained at a depth of less than 5 nm from the surface. Naturally, it includes a layer made of copper nitride.

  In the low reflection layers 31b and 41b configured using such copper nitride, the metallic luster is reduced as compared with the metallic luster in the main body layers 31a and 41a. The tinged color has been reduced. Further, the low reflection layers 31b and 41b formed using such copper nitride have a significantly reduced reflection Y value compared to a layer made of copper nitride not containing oxygen atoms at a depth of 5 nm or more from the surface. Has been. For this reason, in this Embodiment, it becomes possible to suppress that invisibility and visibility fall by the reflected light from the 1st antenna conducting wire 31 or the 2nd antenna conducting wire 41. FIG.

  The low reflection layers 31b and 41b have a smaller thickness than the main body layers 31a and 41a. Specifically, the low reflection layers 31b and 41b have a thickness in the range of 10 nm to 60 nm. Therefore, it is suppressed that the thickness of the whole conducting wire becomes large. This suppresses reflection of external light or the like on the side surface of the first antenna conductor 31 or the second antenna conductor 41.

  Moreover, the reflectance of the light in the 1st antenna conducting wire 31 or the 2nd antenna conducting wire 41 can be made low also by setting the thickness of the low reflection layers 31b and 41b in the range of 10 nm-60 nm. Although this is not limited, for example, thin film interference occurring in the low reflection layers 31b and 41b can be mentioned. The thin film interference is a phenomenon in which light reflected on one surface of the low reflection layers 31b and 41b interferes with light reflected on the other surface of the low reflection layers 31b and 41b. By setting the thicknesses of the low reflection layers 31b and 41b within the above-mentioned range of 10 to 60 nm, thin film interference occurs so as to weaken the reflected light, whereby light in the first antenna lead 31 or the second antenna lead 41 is generated. It can be considered that the reflectivity of is reduced.

  A method for forming the thin low reflection layers 31b and 41b as described above is not particularly limited, and a known thin film forming method such as a sputtering method, a vacuum evaporation method, a CVD method, an ion plating method, an electron beam method, or the like. Can be used. For example, when sputtering is used, oxygen is applied to a depth of 5 nm or more from the surface by applying discharge power to a target made of copper in an environment where nitrogen gas and oxygen gas controlled to a predetermined partial pressure exist. A layer made of copper nitride containing atoms can be obtained.

  In the present embodiment, the low reflection layers 31b and 41b are laminated on the main body layers 31a and 41a. However, the low reflection layers 31b and 41b are the surfaces of the main body layers 31a and 41a on the base material 20 side or the base layers. You may laminate | stack on the surface of the material 20, and the surface on the opposite side. Further, a blackening layer may be used in place of the low reflection layers 31b and 41b. For example, although the low reflection layer 31b is provided in the main body layer 31a, an aspect in which a blackening layer is provided in the main body layer 41a may be employed.

(Surface characteristics of the first antenna layer and the second antenna layer)
Moreover, in this Embodiment, the device for reducing the haze in the antenna 10 is also made | formed. Hereinafter, the surface characteristics of the first antenna layer 30 and the second antenna layer 40 in the present embodiment will be described. In the present embodiment, in order to reduce haze in the antenna 10, the surface of the first antenna layer 30 and the second antenna layer 40 on the base material 20 side is devised. In this example, the surface characteristics of the first antenna layer 30 and the second antenna layer 40 are the same. Therefore, hereinafter, the first antenna layer 30 and the second antenna layer 40 will be described together.

Specifically, in the present embodiment, the total light reflectance ( _RSCI) measured according to JIS Z 8722 of the smooth surfaces 30a, 40a of the first antenna layer 30 and the second antenna layer 40 on the transparent adhesive layer 12 side. ) (R _SCE / R _SCI ) ratio of diffuse light reflectivity (R _SCE ) to 0.4) or less.

As described above, in the present embodiment, the main body layers 31a and 41a are made of a copper foil (copper thin film) laminated on the base material 20 with the transparent adhesive layer 12 interposed therebetween. In this case, the opening regions 32 and 42 of the first antenna layer 30 and the second antenna layer 40 provided on the base material 20, that is, the exposed surface of the transparent adhesive layer 12, on the base material 20 side of the copper foil. The fine uneven shape of the facing surface (smooth surface with low light scattering property) is transferred. Therefore, the diffusion of the surface of the transparent adhesive layer 12 exposed from the opening regions 32 and 42 of the first antenna layer 30 and the second antenna layer 40 with respect to the total light reflectance ( _RSCI ) measured in accordance with JIS Z8722. The ratio (R _SCE / R _SCI ) of the light reflectivity (R _SCE ) and the conductors 31 and 41 of the first antenna layer 30 and the second antenna layer 40, that is, the first antenna layer 30 and the second antenna layer 40. the ratio of the surface in contact with the transparent adhesive layer 12 total light reflectance was measured in conformity with JIS Z 8722 of (lower smooth surface of the light scattering) _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE} / R _SCI ) is considered to be an equivalent value.

Therefore, in the present embodiment, the numerical value of the light reflectance ratio ( _RSCE / _RSCI ) on the surface of the transparent adhesive layer 12 exposed from the opening regions 32, 42 of the first antenna layer 30 and the second antenna layer 40 is Because it is difficult to measure directly (because most of the light is transmitted through the exposed adhesive layer);
Base material 20 / transparent adhesive layer 12 / first antenna layer 30 and second antenna layer 40
In the laminate, measurement light is incident from the base material 20 side, passes through the intervening base material 20 and the transparent adhesive layer 12, and is reflected on the surfaces of the first antenna layer 30 and the second antenna layer 40. The numerical value of (R _SCE / R _SCI ) is measured by light and evaluated indirectly.

  As a result of the experiments by the present inventors, the surface of the copper foil to be bonded to one surface of the base material 20 via the transparent adhesive layer 12 is smooth and exposed to the opening regions 32 and 42 to which the surface is transferred. It was confirmed that the surface of the transparent adhesive layer 12 to be able to reduce the haze of the antenna 10 obtained when light transmission is mainly parallel light transmitted light.

  Further, the present inventor has found that the surface of the metal foil can be distinguished from the rough surface and the mirror surface in appearance, but there is no difference in the numerical value represented by the JIS B 0601 arithmetic average roughness Ra. Here, the arithmetic average roughness Ra of JIS B 0601 is the reference length L extracted from the roughness curve in the direction of the average line, and the absolute value of the deviation from the average line of the extracted part to the measurement curve is summed. The average value. Further, in the experiment, even when the Ra of the rough surface of a certain metal foil is larger than the Ra of the rough surface of a metal foil different from this, when an antenna is produced from these metal foils, a metal with a large Ra It was also found that the foil had a smaller haze value after the etching treatment. Furthermore, in a certain metal foil, the mirror surface Ra is smaller than the rough surface Ra, but it has also been found that the mean square roughness Rq measured in a minute range is larger in the mirror surface than in the rough surface.

  From the above results, the present inventor found that the arithmetic mean roughness Ra was between the haze value transferred to the surface of the transparent adhesive layer 12 in the open regions 32 and 42 after the etching process and the appearance of the metal foil surface. We found that there was no correlation. The correlation between the ten-point average roughness (specified in JIS B 0601 (1994 version)) that has been used as an index of specularity in the past and the haze transferred to the adhesive layer surface is the same. Not clear. Moreover, the average roughness showing the uneven | corrugated shape on the surface of metal foil changes with the methods to measure. From this, in the same arithmetic mean roughness Ra, the surface shape having a high unevenness frequency and a close unevenness interval has a large haze value after the etching process, while the unevenness frequency is low and the uneven interval is low. It is considered that the haze value after the etching process is small in a surface shape with a sparse and many flat portions.

  That is, conventionally, the haze after the etching process has been reduced in correlation with the ten-point average roughness Rz because the conditions such as the roughness of the rough surface of the metal foil surface, the density of the protrusions, etc. It is concluded that it is not a design standard that can be widely applied in general when the manufacturing method of metal foil, the rough surface fine uneven shape of the surface, the density of protrusions, etc. vary in various ways. The

As a result of the above studies, the present inventors can reduce the haze after the etching process with good correlation by making the surface of the copper foil to be bonded to the transparent adhesive layer 12 side into a mirror surface with low light scattering property. I found. Specifically, the surface of the copper foil to be bonded to one surface of the substrate 20 via the transparent adhesive layer 12 is a diffused light with respect to the total light reflectance ( _RSCI ) measured in accordance with JIS Z8722. When the ratio of reflectance ( _RSCE ) ( _RSCE / _RSCI ) is in the range of 0.4 or less, the first antenna layer 30 after the etching process and the surface regardless of the arithmetic mean roughness Ra of the surface, It has been found that the haze of light transmitted through the opening regions 32 and 42 of the second antenna layer 40 can be reduced. Therefore, as described above, with respect to the total light reflectance ( _RSCI ) measured according to JIS Z 8722 of the smooth surfaces 30a, 40a of the first antenna layer 30 and the second antenna layer 40 on the transparent adhesive layer 12 side. It is specified that the ratio of diffused light reflectance ( _RSCE ) ( _RSCE / _RSCI ) is 0.4 or less. This ratio (R _SCE / R _SCI ) is more preferably 0.3 or less.

The ratio of the total light reflectance diffuse light reflectance for _{(R SCI) (R SCE)} (R SCE / R SCI) is an indicator that the surface shape of the metal foil (copper foil) represents whether easily scatters light When the shape of the surface of the metal foil (copper foil) is transferred to the transparent adhesive layer 12, the value directly affects the haze of the transmitted light of the antenna obtained. In the present embodiment, the surfaces of the first antenna layer 30 and the second antenna layer 40 on the base material 20 side are smooth surfaces 30a and 40a having low light scattering properties (select such surfaces of the copper foil). the by), the ratio of the diffuse light reflectance to the total light reflectance of the surface of the transparent adhesive layer 12 in the opening region 32, 42 of the first antenna layer 30 and the second antenna layer _{40 (R SCI) (R SCE} ) ( _RSCE / _RSCI ) can be set to the above specific range, and the surface of the transparent adhesive layer 12 has a shape that hardly scatters transmitted light, so that haze can be reduced. In addition, the said specific reflective characteristic is acquired by raising the polish degree of the rolling roll surface which contacts the copper foil which forms the 1st antenna layer 30 and the 2nd antenna layer 40. FIG.

Total light reflectance was measured in accordance with JIS Z 8722-1982 of the copper foil surface in the present embodiment _{(R SCI)} is in conformity with JIS Z 8722-1982, spectrophotometer (e.g., Konica Minolta Sensing CM-3600d) manufactured by Co., Ltd. is set to the reflection mode, the light source is standard light D65, the visual field is 2 °, the measurement diameter is 4 mmφ or more, and both the diffuse reflection light and the specular reflection light are reflected in the detector. The Y value (Y of tristimulus values XYZ) is measured by setting the SCI (Special Component Include) mode in which the (integrated) intensity of the total reflected light is measured. Further, JIS Z 8722-1982 diffuse light reflectance was measured according to the copper foil surface _{(R SCE)} is similarly using spectrophotometer, a light source, field of view, and measuring the diameter is the same as the The detector is set to an SCE (Special Component Exclude) mode that measures the (integral) intensity of only the diffuse reflected light of the reflected light, and the Y value (Y of tristimulus values XYZ) is measured. is there. Here, the tristimulus value XYZ is defined by JIS Z 8722-1982. A sample placed in an ideal environment is illuminated with a standard light source, and the spectroscopic analysis result of reflected light from the sample is calculated. It is a value to be determined.

As described above, the degree of haze reduction has a low dependency (correlation) on the arithmetic average roughness Ra defined in JIS B 0601. However, if the value of Ra becomes too large, there is generally no mistake in increasing the surface irregularities, so the haze of the exposed surface of the transparent adhesive layer 12 tends to increase (weak correlation). In view of this point, it can be said that it is preferable to select a small Ra within a possible range on the assumption that a specific light reflectance ratio (R _SCE / R _SCI ) is set. Usually, Ra is set to 0.2 μm or less, more preferably 0.15 μm or less.

(Use)
Next, the use of the antenna 10 according to the present embodiment will be described. As an application of the antenna 10, first, an antenna for a mobile phone is cited. In this case, for example, as shown in FIG. 4, the antenna 10 may be attached to a part of the casing 1 a of the mobile phone 1. The antenna 10 is configured to receive and transmit radio waves for telephone / internet communication functions, television and radio broadcasts, GPS (Global Positioning System) satellites, and the like. May be. The illustrated mobile phone 1 is of a two-fold type, and includes a display screen (subwindow) 1b on the outer surface in a folded state. And the antenna 10 is affixed on the whole display range of the display screen 1b. A feeding electrode (not shown) of the antenna 10 is connected to a transmission / reception unit in the mobile phone 1 via an input / output terminal provided on the outer frame of the display screen 1b. The antenna 10 may be partially attached to a part of the display screen 1b.

  The antenna 10 may be a car navigation antenna. In this case, for example, as shown in FIG. 5, the antenna 10 may be attached to the windshield 2 a of the automobile 2. The antenna 10 may be connected to the TV tuner of the car navigation device 2b and configured to transmit and receive radio waves from GPS satellites.

  The antenna 10 may be a security system antenna. In this case, for example, as shown in FIG. 6, the antenna 10 may be attached to the window glass 3 a of the building 3. The antenna 10 may be configured to transmit a signal to the receiving device when the window glass 3a is broken, thereby detecting an abnormality.

  The antenna 10 may be a product management antenna. In this case, for example, as shown in FIG. 7, in the RFID (radio frequency identification) tag 4 including the IC chip 4a and the antenna 10, when the antenna 10 receives the calling radio wave from the reader / writer, the RFID chip 4a stores the calling radio wave in the memory of the IC chip 4a. The antenna 10 may be configured to transmit information to the reader / writer. Thereby, information processing such as product entry / exit, inventory, and sales management may be performed.

The antenna 10 may be configured to receive radio waves of ETC (Electric Toll Collection System) (not shown).
In addition, in the range which does not inhibit the function of the 1st and 2nd antenna layer, the layer which expresses another function other than both antenna layers may be provided side by side. As a layer which expresses another function, the position detection electrode layer which comprises a touch panel and a touch switch is mentioned, for example. In particular, it is preferable that a touch panel or a touch switch having a mesh electrode pattern that is the same as or similar to the two antenna layers is provided. Here, the antenna layer and the touch panel or touch switch layer may be insulated or electromagnetically shielded from each other on the same layer as the antenna layer, or provided on different layers. For example, in FIG. 5, it is preferable that the antenna is on the outer surface side of the vehicle and the other functions are on the inner side of the vehicle.

(Antenna manufacturing method)
Next, a method for manufacturing the antenna 10 will be described. In the manufacturing method of the present embodiment, first, the total light reflectance was measured in conformity with JIS Z 8722 _{(R SCI)} diffuse light reflectance for the ratio of _{(R SCE) (R SCE /} R SCI) is 0.4 A step of preparing a copper foil having the following surfaces is performed. The copper foil used here has a surface having the specific reflection characteristics (smooth surface with low light scattering property).

Next, the copper foil is placed on the first surface 20a that is one surface of the base material 20 and the second surface 20b that is the other surface through the transparent adhesive layer 12, and the R _SCE / R _SCI is 0. The process of laminating | stacking the surface below 4 facing the base material 20 is performed. In this step, first, a base material 20 is prepared, and a transparent adhesive layer 12 is formed by coating the first surface 20a and the second surface 20b of the base material 20 with a transparent adhesive. As a layer forming method of the transparent adhesive layer 12, a known layer forming method, for example, a coating method such as roll coating, comma coating, gravure coating, die coating, or screen printing or gravure in which partial formation in an arbitrary shape is easy. Printing methods such as printing can be appropriately employed. Next, the copper foil is laminated on the surface of the transparent adhesive layer 12 of the substrate 20 with the smooth surface side having a low light scattering property facing.

  Next, a copper nitride layer to be the low reflection layers 31b and 41b after completion is laminated on the copper foil on the transparent adhesive layer 12 of each of the first surface 20a and the second surface 20b. As a method for forming the copper nitride layer, a thin film forming method such as a sputtering method can be used as described above.

  Next, a process of forming the first antenna layer 30 and the second antenna layer 40 by etching the copper foil and the copper nitride layer into a predetermined pattern shape is performed. In this step, first, a resist layer is provided in a predetermined mesh pattern shape corresponding to the first antenna layer 30 and the second antenna layer 40 on the copper foil and the copper nitride layer laminated on the base material 20, and the resist The first antenna layer 30 and the second antenna layer 40 are formed by an etching method of removing the resist layer after removing the copper foil and the copper nitride layer that are not covered with the layer by etching (corrosion). . Among the etching processing methods, it is preferable to adopt a so-called photolithography method from the viewpoint of fine processing accuracy.

  In the present embodiment, a photolithography method is performed as follows. That is, first, a photosensitive resist layer is formed in a predetermined pattern on the copper nitride layer of the substrate 20. The photosensitive resist layer has photosensitivity to light in a specific wavelength range, for example, ultraviolet rays. The type of the photosensitive resist layer is not particularly limited. For example, a photodissolvable photosensitive resist layer may be used, or a photocurable photosensitive resist layer may be used. Here, an example in which a photodissolvable photosensitive resist layer is used will be described.

  The photosensitive resist layer is formed in a pattern corresponding to the pattern of the first antenna layer 30 and the second antenna layer 40. For example, first, the photosensitive resist layer is coated on the entire surface of the copper nitride layer with a coater using a coater, and then the photosensitive resist material is exposed and developed in a predetermined pattern. Thus, a photosensitive resist layer having a predetermined pattern shape is formed.

  Next, copper foil and copper nitride are etched using the photosensitive resist layer as a mask. As described above, both the copper foil and the copper nitride are configured to contain copper. For this reason, copper foil and copper nitride can be etched simultaneously using the etching liquid which can dissolve copper. For example, an aqueous ferric chloride solution is used as the etching solution.

  Next, the photosensitive resist layer remaining on the main body layers 31a and 41a and the low reflection layers 31b and 41b formed by etching is washed with a chemical solution that dissolves and removes the film, and a film removal process is performed. Thereby, the photosensitive resist layer can be removed. In this manner, the first antenna layer 30 having the main body layer 31a and the low reflection layer 31b is provided on the first surface 20a of the substrate 20, and the second antenna layer 40 having the main body layer 41a and the low reflection layer 41b is used as the base. By being provided on the second surface 20b of the material 20, the antenna 10 of the present embodiment is manufactured.

(effect)
The antenna 10 according to the present embodiment described above includes a base material 20 formed in a sheet shape, a mesh-shaped first antenna layer 30 provided on the base material 20 and having light shielding properties and conductivity, and a base. A second antenna layer 40 having a mesh shape provided on the material 20 and having light shielding properties and conductivity. When viewed from the normal direction of the base material 20, the first antenna layer 30 is a second antenna layer. It overlaps with 40. According to such an antenna 10, both the first antenna layer 30 and the second antenna layer 40 have a mesh shape, and overlap each other when viewed from the normal direction of the base material 20, so that a plurality of antennas can be efficiently used in space. It is possible to secure suitable invisibility while consolidating functions.

  In the antenna 10 according to the present embodiment, the first antenna layer 30 has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the first antenna opening regions 32 having a constant shape intersect. The second antenna layer 40 has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the second antenna opening region 42 having a constant shape intersects, and the second antenna layer 40 and the first antenna layer The two antenna layers 40 are arranged so that the mesh pattern shapes are similar to each other and in the same direction, and each pitch of the first antenna opening regions 32 in each direction in which the first antenna opening regions 32 are arranged is It is an integral multiple of each pitch of the second antenna opening area 42 in each direction in which the second antenna opening area 42 is arranged. According to such an antenna 10, when viewed from the normal direction of the base material 20, the first antenna conductor 31 overlaps the second antenna conductor 41, and the first antenna conductor 31 is externally connected to the second antenna conductor 41. An integrated state can be obtained. In this case, in the antenna 10, the first antenna conductor 31 does not affect the light shielding property, and the transmittance is defined by the second antenna opening region 42. In other words, when viewed from the normal direction of the substrate 20, the mesh pattern shape of the finer antenna layer (in this example, the second antenna layer 40) appears on the appearance and is invisible depending on the finer antenna layer. Sex can be obtained. Thereby, it can suppress that the invisibility of the whole antenna 1 falls by a some antenna layer overlapping.

  Further, in the antenna 10 according to the present embodiment, at least one of the first antenna conductor 31 and the second antenna conductor 41 is composed of a main body layer 31a, 41a made of a metal material and a base material with respect to the main body layers 31a, 41a. Low reflection layers 31b and 41b made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface, laminated on the side opposite to the 20 side and / or the base material 20, and the low reflection layers 31b and 41b Is 10 nm to 60 nm, and the reflection Y value of the low reflection layers 31b and 41b is 30% or less. According to such an antenna 10, it is possible to suppress the reddish light from reaching the observer due to the metallic luster of copper by the low reflection layers 31b and 41b. Moreover, since the film thickness of the low reflection layers 31b and 41b is 10 nm to 60 nm and the reflection Y value of the low reflection layers 31b and 41b is 30% or less, preferably 27% or less, the first antenna conductor 31 or the second It can suppress that visibility falls by the reflected light from the antenna conducting wire 41. FIG. Further, since both the main body layers 31a and 41a and the low reflection layers 31b and 41b contain copper, the main body layers 31a and 41a and the low reflection layer 31b can be obtained by using an etchant that can selectively dissolve copper. 41b can be formed simultaneously. For this reason, the man-hour required in order to produce the 1st antenna layer 30 and the 2nd antenna layer 40 can be made small.

Furthermore, in the antenna 10 in the present embodiment, the first antenna layer 30 and the second antenna layer 40 include copper as a main component, and are provided on one surface of the base material 20 via the transparent adhesive layer 12. Ratio of diffused light reflectivity (R _SCE ) to total light reflectivity (R _SCI ) measured in accordance with JIS Z 8722 on the transparent adhesive layer 12 side surfaces of the first antenna layer 30 and the second antenna layer 40 (R _SCE / R _SCI ) is 0.4 or less. According to such an antenna 10, since the surface of the transparent adhesive layer 12 has a shape that hardly scatters transmitted light, haze can be reduced.

  Various modifications can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(Modification including a plurality of base materials)
In the embodiment described above, the number of the base material 20 is one, but the base material 20 may include a plurality of base materials. Below, although the base material 20 demonstrates the modification which contains two base materials, the base material 20 may contain the 3 or more base materials.

  FIG. 8 is a cross-sectional view of the antenna corresponding to FIG. In the example shown in FIG. 8, the base material 20 includes a first base material 21 and a second base material 22. The first base material 21 is provided with a first antenna layer 30, and the second base material 22 is provided with a second antenna layer 40. The first base material 21 and the second base material 22 are laminated and joined to each other by the transparent joining layer 15. Even with such a configuration, it is possible to secure suitable invisibility while aggregating a plurality of antenna functions in a space efficient manner.

  The transparent bonding layer 15 is not particularly limited as long as the transparent bonding layer 15 has sufficient transparency and can bond the first base material 21 and the second base material 22, and the transparent adhesive layer 12 is not limited. It may be the same. Moreover, since the film thickness of the transparent joining layer 15 adheres the 1st base material 21 and the 2nd base material 22, it is preferable that it is the same as the film thickness of the 2nd antenna layer 40, or more. . Furthermore, the refractive index of the transparent bonding layer 15 is preferably in the range of 1.41 to 1.59 from the viewpoint of interface reflection reduction due to the difference in refractive index between the first base material 21 and the second base material 22, Furthermore, it is preferable to be within the range of 1.48 to 1.52. The transparent bonding layer 15 is not only provided between the first base material 21 and the second base material 22 and not provided with the second antenna layer 40, but also the second antenna opening of the second antenna layer 40. It also exists in region 42. That is, the second antenna layer 40 is embedded in the transparent bonding layer 15.

Moreover, in this modification, the 1st antenna layer 30 contains copper as a main component, and is provided in any one of a pair of mutually opposing surfaces of the 1st base material 21 through the transparent adhesive layer 12. FIG. but the ratio of total light reflectance was measured in conformity with JIS Z 8722 of the first antenna layer 30 transparent adhesive layer 12 side surface _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R SCI ) May be 0.4 or less. Similarly, the second antenna layer 40 includes copper as a main component, and is provided on any one of a pair of surfaces facing each other of the second base material 22 with the transparent adhesive layer 12 interposed therebetween. the ratio of the second transparent adhesive layer 12 side total light reflectance was measured in conformity with JIS Z 8722 of the surface of the antenna layer 40 _{(R SCI)} diffuse light reflectance for _{(R SCE) (R SCE /} R SCI) is It may be 0.4 or less.

(Modification with mesh layer)
In addition to the embodiment described above, a mesh layer 50 may be further provided on at least one surface of the substrate 20. 9 to 11 are diagrams for explaining the antenna 10 provided with the mesh layer 50. FIG. 9 is a plan view showing an antenna 10 of the present modification corresponding to FIG. FIG. 10 is an enlarged view of a region indicated by X in FIG. 9 corresponding to FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10, corresponding to FIG.

  As shown in FIG. 9, the antenna 10 of the present modification includes a mesh-like mesh layer 50 having a light shielding property on the first surface 20 a of the substrate 20. Similar to the first antenna layer 30 and the second antenna layer 40, the mesh layer 50 includes a plurality of mesh conductors 51 arranged in a mesh pattern on the substrate 20, and a plurality of mesh openings are formed by the plurality of mesh conductors 51. Region 52 is defined. The mesh conducting wire 51 means a linear portion that extends between two branch points 53 at a plurality of branch points 53 scattered in the mesh layer 50 and defines a mesh opening region 52.

  10 and 11, when the base material 20 is viewed from the normal direction, the mesh layer 50 is a portion of the first surface 20a of the base material 20 where the first antenna layer 30 is not provided, that is, One antenna layer 30 is provided outside. Therefore, when the base material 20 is viewed from the normal direction, the mesh layer 50 overlaps the second antenna layer 40 at the overlapping portion R. A gap G is provided between the first antenna layer 30 and the mesh layer 50. Even with such a configuration, the invisibility of the antenna layer 20 can be easily increased.

  Moreover, in this modification, when viewed from the normal direction of the base material 20, for example, the first antenna layer 30 in all four directions among the four directions of the top, bottom, left, and right determined on the base material 20 corresponding to the top, bottom, left, and right of the drawing. The mesh layer 50 is located on the outside. The present invention is not limited to such a mode. For example, the mesh layer 50 is located outside the first antenna layer 30 in at least two of the above four directions, ie, the upper, lower, left, and right directions. Is preferred. This is because the first antenna layer 30 can be made sufficiently inconspicuous.

(Modified example with variable opening area)
FIG. 12 is a plan view of the first antenna layer 30 of the antenna 10 according to the modified example in which the opening area is varied, FIG. 13 is an enlarged view of FIG. 12, and FIG. 14 is a general image display. It is a figure which shows the mechanism 5. FIG. As shown in FIGS. 12 and 13, in this modified example, in the first antenna layer 30, the first antenna opening region 32 has its opening area changed by changing its shape without greatly disturbing the periodicity of the arrangement. It is designed to be scattered. Although not shown, the second antenna layer 40 is the same. This modification differs from the above-described embodiment in this point.

In the display area of the image display mechanism 5 shown in FIG. 14, pixels P for forming an image are regularly arranged. The antenna 10 is also assumed to be installed on a film that covers the image display mechanism 5. In the general image display mechanism 5, pixels are arranged at a constant pitch both in the horizontal direction (direction d _x in FIG. 14) in the installation state of the image display mechanism 5 and in the direction d _y (for example, the vertical direction) orthogonal to the horizontal direction. P is arranged. Note that, as in the example illustrated in FIG. 14, each pixel P generally includes a plurality of subpixels RP, GP, and BP. When the antenna 10 overlaps the image display mechanism 5 having the pixel arrangement, when the opening areas 32 and 42 of the first antenna layer 30 and the second antenna layer 40 of the antenna 10 are regularly arranged, the regularity of the pixel P is determined. There is a possibility that a striped pattern resulting from the (periodic) pattern and the arrangement pattern of the opening regions 32 and 42 of the first antenna layer 30 and the second antenna layer 40, that is, moire, is visually recognized.

  In general, in a member having a mesh pattern, it has been considered that making the mesh pattern irregular, that is, breaking the periodicity of the pattern arrangement is effective for invisibility of moire. However, according to the study by the present inventors, the pattern of the first antenna layer 30 and the second antenna layer 40 is aperiodic to such an extent that the moire is sufficiently inconspicuous, that is, the opening regions 32 and 42 are not made. When regularly arranged, moire can be made inconspicuous, but in turn, it has been found that shading unevenness due to density variation of the open regions 32 and 42 becomes conspicuous. That is, it has been found that the moire reduction and the shading reduction are incompatible with each other. Until now, various measures for invisibility of such moire or shading unevenness have been studied, but none of them has effectively made both moire and shading unevenness inconspicuous.

  On the other hand, the inventors of the present invention have an opening area of the opening regions 32 and 42, in other words, a region inside the plurality of conducting wires 31 and 41 surrounded by the plurality of conducting wires 31 and 41 that define the opening regions 32 and 42. Focusing on the variation of the area, we conducted extensive research. As a result, the inventors of the present invention can make the moire inconspicuous very effectively by imposing restrictions on the variation in the opening area of the opening regions 32 and 42, and at the same time, the unevenness of the shade is extremely effective. It was found that both can be made inconspicuous. Such an effect simply performs pattern irregularization as moiré invisibility, while simply pattern regularization as shading unevenness, resulting in both moire and shading unevenness. It can be said that this is a remarkable effect that exceeds the predicted range from the state of the art that could not be made invisible. Hereinafter, a preferable distribution of the opening areas of the opening regions 32 and 42 in the first antenna layer 30 and the second antenna layer 40 will be described from the viewpoint of making both moire and shading unevenness invisible.

First, it is preferable that the average value m of the opening area of the opening region 32 in the first antenna layer 30 and the standard deviation σ of the area of the opening region 32 satisfy the following formula (a).
3 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 20 (a)

  In addition, Formula (a) can also be described as 3 ≦ 3σ / m × 100 ≦ 20. When this formula (a) is satisfied, it is possible to effectively prevent the moire and the shading unevenness from being visually recognized due to the target first antenna layer 30. Similarly, regarding the second antenna layer 40, it is preferable that the above-described formula (a) is satisfied when the average value m of the opening area of the opening region 42 and the standard deviation σ of the area of the opening region 42 are used.

Here, when the graph normal variable X of the standard normal distribution conforms to N (m, σ ² ), the probability that X is included in the range where the deviation from the average value m is ± 1.5 × σ or less is 86.64%. . Therefore, “m + 1.5σ” in the equation (a) indicates that the distribution of the opening areas 32 and 42 included in one target first antenna layer 30 and second antenna layer 40 follows a normal distribution. Assuming that the aperture area value is within 86.64% centered on the average among all aperture area values of all aperture regions 32 and 42 included in one first antenna layer 30 and second antenna layer 40. It means the maximum value at. Similarly, “m−1.5σ” in the formula (a) indicates that the distribution of the opening areas 32 and 42 included in one target first antenna layer 30 and second antenna layer 40 is a normal distribution. Assuming that the first and second antenna layers 30 and 40 are included in one of the first antenna layer 30 and the second antenna layer 40, the opening area is within 86.64% centered on the average among all opening area values of the opening areas 32 and 42. It means the minimum value among the values.

When the present inventor has conducted extensive research, when the formula (a) is satisfied, that is, for the average value (m) of “3σ” which is the difference between “m + 1.5σ” and “m−1.5σ”. When the ratio is 3% or more and 20% or less as a percentage, both moire and shading unevenness can be effectively made inconspicuous to such an extent that it does not become a problem in normal use in combination with the image display mechanism 5. It was. Further, when the following expression (b) was satisfied, it was made inconspicuous to the extent that neither moiré nor shading unevenness was felt in normal observation. Furthermore, when the following formula (c) is satisfied, even if the presence of moiré and shading unevenness is carefully observed, it is possible to make the moiré and shading unevenness invisible to such an extent that they cannot be visually recognized. .
4 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 15 (b)
5 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 10 (c)

Furthermore, as a result of repeated studies by the inventors of the present invention, when the following equation (d) is satisfied, it should be made inconspicuous to the extent that neither moiré nor shading is felt in normal observation. When the following equation (e) is satisfied, even if the presence of moiré shading is carefully observed, it can be made invisible to the extent that both moiré and shading unevenness cannot be visually recognized. It was.
4 ≦ (((m + 2σ) − (m−2σ)) / m) × 100 ≦ 25 (d)
5 ≦ (((m + 2σ) − (m−2σ)) / m) × 100 ≦ 15 (e)

Here, when the graph normal variable X of the standard normal distribution follows N (m, σ ² ), the probability that X is included in the range where the deviation from the average value m is ± 2 × σ or less is 95.44%. That is, in the expressions (d) and (e), the ratio of the opening areas 32 and 42 that should consider the opening area values of all the opening areas 32 and 42 increases as compared with the expressions (a) to (c). . Therefore, it is possible to control the overall distribution of the opening areas of the opening regions 32 and 42 included in the first antenna layer 30 and the second antenna layer 40 with higher accuracy. For this reason, the ratio in the formulas (d) and (e) represented by “((m + 2σ) − (m−2σ)) / m) × 100” represents “((m + 1.5σ) − (m It is considered that the same effect can be ensured even if the ratio is set larger than the ratio in the formulas (b) and (c) represented by −1.5σ)) / m) × 100 ”.

  In addition, the opening area of each opening area | region 32 and 42 contained in one 1st antenna layer 30 and the 2nd antenna layer 40 can be specified based on the image data acquired by an image processing apparatus as an example. For example, first, an enlarged photograph of the first antenna layer 30 and the second antenna layer 40 is taken from the normal direction of the film with a camera-equipped microscope to obtain an image in which the opening region is black and the mesh portion is white. Next, the illumination unevenness is removed from the image by a spatial frequency high-pass filter, and further binarized using a discriminant analysis method (for example, binarization processing by Otsu). Thereafter, the number of pixels in the closed region is counted for the binarized image, and the number of pixels is converted to the actual size. The conversion to the actual size can be calculated from the image resolution.

  Returning to FIG. 12, an example of the first antenna layer 30 in this modification is shown. The pattern of the first antenna layer 30 includes the first antenna layer 30 according to this modification, which is formed by a plurality of line segments 61 that extend between two intersections 63 and define an opening region (opening) 62. Based on the reference mesh pattern 60 (see FIG. 13) that is the basis for generation, the reference mesh pattern is determined to be modified so as to be irregularly arranged as appropriate. More specifically, the pattern of the first antenna layer 30 includes a reference mesh pattern 60 in which the opening regions 62 are regularly arranged. In other words, the reference mesh pattern 60 in which the opening regions 62 are arranged with periodicity. As a basis, the shape of the opening region 62 is changed to such an extent that the moire can be sufficiently invisible while maintaining the uniformity of the arrangement position of the opening region 62 so as not to cause unevenness in density. It is determined by varying the opening area.

  In the present modification, the patterns of the first antenna layer 30 and the second antenna layer 40 are determined based on the reference mesh pattern 60 shown in FIG.

  Hereinafter, an example of a method for determining the pattern of the first antenna layer 30 and the second antenna layer 40 in this modification will be described. In the method described below, a step of determining a reference mesh pattern 60 formed from a plurality of line segments 61 extending between two intersection points 63 and defining an open region 62, and the intersection point 63 of the reference mesh pattern 60 is determined. Based on the step of determining the positions of the branch points 33 and 43 in the first antenna layer 30 and the second antenna layer 40 based on the line segment 61 of the determined branch points 33 and 43 and the reference mesh pattern 60, the first antenna And determining the positions of the conducting wire 31 and the second antenna conducting wire 41. Hereinafter, each step will be described in order.

First, in the step of determining the reference mesh pattern 60, a regular pattern serving as a basis for the first antenna layer 30 and the second antenna layer 40, that is, the reference mesh pattern 60 is determined. The reference mesh pattern 60 determined here is formed of a plurality of line segments 61 that extend between two intersections 63 and define an open region 62. In this reference the mesh pattern 60, are regularly arranged in the first direction d ₁ and the second direction d ₂ similar to the direction described in the embodiment the opening region 62 of constant geometry intersects. The reference mesh pattern 60 may include a plurality of types of opening regions 62, and the various types of opening regions 62 may be regularly arranged in two or more directions that intersect.

As shown in FIG. 13, in the illustrated reference mesh pattern 60, a fixed rectangular opening region 62 is a pattern that is spread without gaps. The opening regions 62 are arranged at a constant pitch in the first direction d ₁ and the second direction d ₂ that intersect each other. Especially, referring mesh pattern 60 shown is, with each plurality of the first straight line 60a group arranged at a constant pitch P1 in a direction perpendicular to the extending and first direction d ₁ linearly in the first direction d ₁ , defined and a second straight line 60b group, each of which is arranged in the second direction d ₂ in a straight line in the extension and the second direction perpendicular to the direction d ₂ constant pitch P1 and the same constant pitch P2, by ing. As a result, all the opening regions 62 included in the reference mesh pattern 60 are formed in the same quadrangular shape, particularly, a rhombus shape.

By the way, generally, from the viewpoint of making the moire caused by the interference between the pixel arrangement of the image display mechanism 5 and the first antenna layer 30 and the second antenna layer 40 invisible, the pixel arrangement directions d _x and d _y in the image display mechanism 5 On the other hand, it is preferable to incline the arrangement direction of the opening regions 32 and 42 of the first antenna layer 30 and the second antenna layer 40. On the other hand, when the present inventors have repeated experiments, in order to invisible moire with square lattice arrayed pixels P shown in FIG. 14, further, even for diagonal d _o of the pixel, the aperture It was effective to incline the arrangement direction of the regions 32 and 42. This is because, as shown in FIG. 14, the light-shielding portions are arranged at regular intervals, with the wide portions 5a1 of the light-shielding portions (for example, black matrix) 5a that define the pixels P arranged at diagonal positions of the pixels P. This is probably because moire between the thick portion 5a1 of 5a and the opening regions 32 and 42 is likely to occur.

The general pixels P arranged in a square lattice have a square shape when viewed from the normal direction of the substrate, that is, in plan view. When using such a pixel P, the diagonal _{d o} is, 45 ° inclined with respect to the pixel arrangement direction _d x, _{d y.} Then, when the present inventors have confirmed, in order to invisible moire between the pixel P of a square shape, the arrangement direction of the opening region 32, 42, orthogonal pixel arrangement direction d _x, one of the d _y d _The angle formed with respect to _x is preferably 30 ° or more and 40 ° or less, more preferably 33 ° or more and 37 ° or less, and most preferably 35 °. In other words, in order to invisible moire between the pixel P of square shape, angular arrangement direction of the opening region 32, 42, which forms with the other d _y of SEQ direction d _x, d _y of pixels perpendicular Is preferably 50 ° or more and 60 ° or less, more preferably 53 ° or more and 57 ° or less, and most preferably 55 °.

On the other hand, in the pattern determination method of the first antenna layer 30 and the second antenna layer 40 described here, the opening regions 32 and 42 of the first antenna layer 30 and the second antenna layer 40 are generally the openings of the reference mesh pattern 60. It follows the arrangement direction of the region 62. The arrangement direction of the opening area 62 in the reference mesh pattern 60 becomes the first direction _{d 1} and the second direction _{d 2.} Therefore, the first direction _{d 1} and the second direction _{d 2} determining the orientation of the opening region 62 included in the reference mesh pattern 60, the arrangement direction _d x of the pixel P that is perpendicular, to one in which _{d x} of _{d y} The angle is preferably 30 ° or more and 40 ° or less, more preferably 33 ° or more and 37 ° or less, and the angles θ _1x and θ _2x of 35 ° may be formed as shown in FIG. Most preferred. The angle θ _x formed by the first direction d ₁ and the second direction d ₂ is preferably 60 ° or more and 80 ° or less, more preferably 66 ° or more and 74 ° or less, as shown in FIG. Most preferably, the angle is 70 °. Further, the first direction d ₁ and the second direction d ₂ determining the orientation of the opening region 62 included in the reference mesh pattern 60, 50 ° to 60 ° with respect to the other d _y of the pixel arrangement direction orthogonal Is more preferable, and an angle between 53 ° and 57 ° is more preferable, and it is most preferable that the angles θ _1y and θ _2y are 55 ° as shown in FIG.

  Next, the process of determining the positions of the branch points 33 and 43 based on the intersection 63 of the reference mesh pattern 60 will be described. In this step, the position of one branch point 23 is determined from one intersection 63 of the reference mesh pattern 60. Specifically, each branch point 33 is arranged on the corresponding intersection point 63 of the reference mesh pattern 60 or at a position shifted from the corresponding intersection point 63 by a length equal to or less than a predetermined length. At this time, the opening regions 32 of the first antenna layer 30 and the second antenna layer 40 finally obtained by irregularly determining the amount of deviation and the direction of deviation from the corresponding intersection 63 of each branch point 33, The shape of 42 does not become constant, and moire can be made inconspicuous effectively. In addition, when the amount of deviation selected irregularly becomes 0, the branch points 33 and 43 may be positioned on the corresponding intersection 63. In addition, by providing a restriction on the amount of deviation from the corresponding intersection 63 of each of the branch points 33 and 43, the conditions of the above-described equations (a) to (e) are satisfied and finally determined. The regularity or uniformity to the extent that shading unevenness can be avoided in the pattern of the first antenna layer 30 and the second antenna layer 40 is ensured.

It should be noted that the amount of deviation of each branch point 33, 43 from the corresponding intersection 63 is less than half the arrangement pitch of the opening regions 62 in order to avoid the conductors 31, 41 from coming into contact with other conductors. Is preferred. This is because if one conductor 31, 41 overlaps with another conductor 31, 41, the portion is visually recognized and may cause uneven shading. Specifically, in order to avoid that the wire 31, 41 is in contact with other conductors 31 and 41, the deviation amount from the corresponding intersection 63 of each branch point 33 and 43, orthogonal to the first direction _{d 1} less than half of the first straight line 60a group arrangement pitch P1 in the direction, and may be less than half of the second straight line 60b groups the arrangement pitch P2 in a direction perpendicular to the second direction d _2.

Further, instead of determining both the amount of deviation from the corresponding intersection 63 and the direction of deviation for each branch point 33, 43, each branch point 33, 43 is preset from the corresponding intersection 63. The deviation amounts in the two directions may be determined respectively. As an example, the arrangement direction _d x of the pixel P of the image display device 5, the deviation amount [delta] _x of the corresponding intersection 63 to _{d y,} [delta] _y (see FIG. 13), then determined for each branch point 33 and 43 You may make it go. In this example, below a certain percentage of arrangement pitch p _x of the opening region 62 along one of the arrangement direction d _x of the pixel P (e.g., 10% or less, preferably 5% or less) is to become so shift amount [delta] _x determined so as to be, and, below a certain percentage of the arrangement pitch p _y open area 62 along the other arrangement direction d _y of the pixel P (e.g., 14% or less, preferably 7% or less) amount deviation such that δ _By determining _y , a restriction may be imposed on the amount of deviation of the branch point 33 from the corresponding intersection 63.

  Next, the process of determining the positions of the conducting wires 31 and 41 will be described. When the positions of the branch points 33 and 43 in the first antenna layer 30 and the second antenna layer 40 are determined as described above, the positions of the conducting wires 31 and 41 are then determined based on the determined branch points 33 and 43. decide. Specifically, the positions of the conductors 31 and 41 so as to extend between the two branch points 33 and 43 respectively corresponding to the two intersections 63 located at both ends of a certain line segment 61 of the reference mesh pattern 60. To decide. The path of the conducting wires 31, 41 between the two branch points 33, 43 may be a straight line, a curved line, a broken line, or a combination of a straight line and a curved line. Also good. Moreover, the line width of the conducting wires 31 and 41 can be set to 0.2 μm or more and 2 μm or less as described above, or may be a thickness outside this range.

  In this way, the first antenna layer 30 and the second antenna layer 40 are formed. Since the positions of the branch points 33 and 43 of the first antenna layer 30 and the second antenna layer 40 are determined based on the position of the intersection 63 of the reference mesh pattern 60 having regularity, the obtained first antenna is obtained. In the layer 30 and the second antenna layer 40, the opening regions 32 and 42 are evenly dispersed to a certain extent, and it is possible to suppress the occurrence of shading. However, the positions of the branch points 33 and 43 are deviated from the positions of the corresponding intersection points 63 by an amount within a predetermined range selected irregularly. Therefore, in the obtained first antenna layer 30 and second antenna layer 40, the regularity or the regularity of the shape or opening area of the opening regions 32 and 42 is lost, and a problem due to moire can be avoided.

  The first antenna layer 30 and the second antenna layer 40, the patterns of which have been determined as described above, are formed by patterning the copper foil or the like formed on the substrate 20 using a photolithography technique. Can be made on top.

In the modification as described above, the average value m of the opening areas 32 and 42 included in the first antenna layer 30 and the second antenna layer 40 and the standard deviation σ of the areas of the opening areas 32 and 42 are expressed by the following equation. (A) is satisfied. As a result, it is possible to effectively prevent the moire and the shading from being visually recognized due to the first antenna layer 30 and the second antenna layer 40 that are the object.
3 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 20 (a)

In addition, the average value m of the opening areas 32 and 42 included in the first antenna layer 30 and the second antenna layer 40 and the standard deviation σ of the area of the opening areas 32 and 42 are expressed by the formula (b) or the formula ( When d) is satisfied, it can be made inconspicuous to the extent that neither moiré nor shading unevenness is felt in normal observation, and further, the formula (c) or the formula (e) In the case where it is satisfied, even if the presence of moire and shading unevenness is carefully observed, it is possible to make it invisible to the extent that both moire and shading unevenness cannot be visually recognized.
4 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 15 (b)
5 ≦ (((m + 1.5σ) − (m−1.5σ)) / m) × 100 ≦ 10 (c)
4 ≦ (((m + 2σ) − (m−2σ)) / m) × 100 ≦ 25 (d)
5 ≦ (((m + 2σ) − (m−2σ)) / m) × 100 ≦ 10 (e)

  In addition, although several modifications with respect to embodiment mentioned above were demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

DESCRIPTION OF SYMBOLS 10 Antenna 12 Transparent adhesive layer 15 Transparent joining layer 20 Base material 20a 1st surface 20b 2nd surface 21 1st base material 22 2nd base material 30 1st antenna layer 30a Smooth surface 30b Non-smooth surface 31 1st antenna conducting wire 31a Body layer 31b Low reflection layer 32 First antenna opening 33 Branch point 40 Second antenna layer 40a Smooth surface 40b Non-smooth surface 41 Second antenna conductor 41a Body layer 41b Low reflection layer 42 Second antenna opening 43 Branch point 50 Mesh layer 60 Reference mesh pattern 61 Line segment 62 Open area 63 Intersection FL1 Contour line

Claims (15)

A base material formed into a sheet,
A mesh-shaped first antenna layer provided on the base material and having light shielding properties and conductivity;
A mesh-like second antenna layer provided on the base material and having light shielding properties and conductivity;
The antenna, wherein the first antenna layer overlaps the second antenna layer when viewed from the normal direction of the substrate. The first antenna layer includes a plurality of first antenna conductors arranged in a mesh pattern on the base material, and defines a plurality of first antenna opening regions by the plurality of first antenna conductors,
The said 2nd antenna layer contains the some 2nd antenna conducting wire arrange | positioned at the said base material at mesh | network form, The some 2nd antenna opening area is defined by these 2nd antenna conducting wire. The described antenna. The first antenna layer has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the first antenna opening regions of a constant shape intersect,
The second antenna layer has a mesh pattern shape arranged at a constant pitch in each of two or more directions where the second antenna opening regions of a constant shape intersect,
The first antenna layer and the second antenna layer are arranged so that the mesh pattern shapes are similar to each other and in the same direction,
Each pitch of the first antenna opening area in each direction in which the first antenna opening area is arranged is an integral multiple of each pitch of the second antenna opening area in each direction in which the second antenna opening area is arranged. The antenna according to claim 2.   When viewed from the normal direction of the base material, the first antenna conductor that defines the first antenna opening area includes at least two or more second antenna conductors that define the second antenna opening area. The antenna according to claim 3, wherein the antenna overlaps with a linear portion connected in a straight line. The first antenna layer has a mesh pattern shape arranged at a constant pitch in each of two directions in which the first antenna opening regions of a constant rectangular shape intersect,
5. The antenna according to claim 3, wherein the second antenna layer has a mesh pattern shape arranged at a constant pitch in each of two directions in which the second antenna opening regions having a constant rectangular shape intersect. . The antenna according to claim 2, wherein an average value m of the area of the first antenna opening region in the first antenna layer and a standard deviation σ of the area of the first antenna opening region satisfy the following expression.
3 ≦ 3σ / m × 100 ≦ 20 The antenna according to claim 6, wherein an average value m of the area of the second antenna opening region in the second antenna layer and a standard deviation σ of the area of the second antenna opening region satisfy the following expression.
3 ≦ 3σ / m × 100 ≦ 20 At least one of the first antenna layer and the second antenna layer is
A body layer made of a metal material;
A low reflection layer made of copper nitride containing oxygen atoms at a depth of 5 nm or more from the surface, laminated on the base material side and / or on the opposite side of the base material with respect to the main body layer;
Including
The film thickness of the low reflection layer is 10 nm to 60 nm,
The antenna according to any one of claims 1 to 7, wherein the reflection Y value of the low reflection layer is 30% or less.   The antenna according to any one of claims 1 to 8, wherein the base material is transparent. The first antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other through the transparent adhesive layer,
Diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the first antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is The antenna according to claim 9, wherein the antenna is 0.4 or less. The second antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other through the transparent adhesive layer,
Diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the second antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is The antenna according to claim 9, wherein the antenna is 0.4 or less.   The said base material contains the 1st base material in which the said 1st antenna layer is provided, and the 2nd base material in which the said 2nd antenna layer is provided, The any one of Claim 1 thru | or 8 An antenna.   The antenna according to claim 12, wherein the first base material and the second base material are transparent. The first antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other of the first base material via a transparent adhesive layer,
Diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the first antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is The antenna according to claim 13, wherein the antenna is 0.4 or less. The second antenna layer includes copper as a main component, and is provided on any one of a pair of surfaces facing each other of the second base material via a transparent adhesive layer,
Diffuse light reflectance to the total light reflectance was measured according to JIS Z 8722 of the transparent adhesive layer side surface of the second antenna layer _{(R SCI)} ratio _{(R SCE) (R SCE /} R SCI) is The antenna according to claim 13, wherein the antenna is 0.4 or less.

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