Antenna structure

Abstract

This invention provides an antenna structure that can reduce manufacturing costs without increasing the size of the enclosure in which the antenna is installed. [Solution] The antenna structure of the present invention comprises an electrically insulating substrate and an antenna body formed on the first surface of the substrate, wherein the substrate and the antenna body are partially or entirely three-dimensionally curved and / or bent.

Description

Technical Field

[0005]

[0001] The present invention relates to an antenna structure having a three-dimensional shape.

Background Art

[0002] Conventionally, a film antenna used by being attached to a window glass of a house, a car, etc. for receiving television broadcasts, etc. is known. For example, Patent Document 1 discloses a film antenna in which a conductor constituting an antenna element is formed on a base material such as a resin film. In this film antenna, a folded dipole antenna is formed on the base material as the antenna element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For a dipole antenna, which is a typical antenna, when the wavelength of the radio wave to be transmitted or received is λ, a conductor (conductive pattern) having a length of λ / 4 is symmetrically arranged with respect to the feeding portion so as to have a total length of λ / 2.

[0005] Therefore, a dipole antenna generally becomes smaller when the frequency of the radio wave to be transmitted or received is high (the wavelength λ of the radio wave is short), and becomes larger when the frequency of the radio wave to be transmitted or received is low (the wavelength λ of the radio wave is long). For example, when the frequency is 2.4 GHz, λ is about 12.5 cm (λ / 2 is about 6.25 cm), and when the frequency is 400 MHz, λ is about 75 cm (λ / 2 is about 37.5 cm).

[0006] However, when a dipole antenna capable of handling several hundred MHz was installed inside the enclosure, the size of the antenna affected the size of the enclosure, leading to a problem of increased manufacturing costs for the device.

[0007] This invention has been made in view of the above problems, and aims to provide an antenna structure that can reduce manufacturing costs without increasing the size of the housing on which the antenna is installed. [Means for solving the problem]

[0008] An antenna structure according to one aspect of the present invention comprises an electrically insulating substrate and an antenna body formed on the first surface of the substrate, wherein the substrate and the antenna body are partially or entirely three-dimensionally curved and / or bent.

[0009] In the antenna structure according to the present invention, the antenna body comprises a first conductive path formed on the first surface of the substrate, a second conductive path formed on the first surface of the substrate on the same straight line as the first conductive path, and a third conductive path formed on the first surface of the substrate parallel to the first conductive path and the second conductive path, and having a length approximately equal to the combined length of the first conductive path and the second conductive path.

[0010] In the antenna structure according to the present invention, the substrate, the first conductive path, the second conductive path, and the third conductive path are curved and / or bent such that the first surface is on the outside and the second surface opposite to the first surface is on the inside.

[0011] In the antenna structure according to the present invention, the substrate, the first conductive path, the second conductive path, and the third conductive path are curved and / or bent such that the first surface is on the inside and the second surface opposite to the first surface is on the outside.

[0012] In the antenna structure according to the present invention, the first conductive path, the second conductive path, and the third conductive path are formed to be embedded in the substrate.

[0013] In the antenna structure according to the present invention, one end of the first conductive path and the second conductive path are connected to a feed line to which alternating current is supplied, and the other end of each is connected to the end of the third conductive path.

[0014] In the antenna structure according to the present invention, the antenna comprising the substrate and the antenna body is a film antenna.

[0015] In the antenna structure according to the present invention, the film antenna is partially or entirely curved and / or bent in three dimensions to match the shape of the object.

[0016] In the antenna structure according to the present invention, the film antenna has an adhesive layer formed by attaching a release sheet to its back surface, and is configured to be attachable to a desired surface. [Effects of the Invention]

[0017] According to the antenna structure of the present invention, manufacturing costs can be reduced without increasing the size of the housing on which the antenna is installed. [Brief explanation of the drawing]

[0018] [Figure 1] A plan view showing an example of the configuration of a film antenna according to one embodiment. [Figure 2] Cross-sectional view along line AA in Figure 1 [Figure 3] Cross-sectional view showing another example of a film antenna configuration. [Figure 4] Perspective view showing a film antenna curved into an arc shape. [Figure 5] Exploded perspective view showing the configuration of the antenna unit. [Figure 6] Cross-sectional view showing the configuration of the antenna unit. [Figure 7] A diagram showing a modified example of the antenna structure of a film antenna. [Figure 8]An enlarged view of region B in FIG. 6, which is a cross-sectional view showing an example of the configuration of a transmission antenna disposed in an antenna installation groove [Figure 9] A cross-sectional view showing another example of the configuration of a transmission antenna disposed in an antenna installation groove [Figure 10] A cross-sectional view showing another example of the configuration of a transmission antenna disposed in an antenna installation groove [Figure 11] A cross-sectional view showing another example of the configuration of a transmission antenna disposed in an antenna installation groove

Embodiments for Carrying out the Invention

[0019] Hereinafter, the detailed configuration of the present invention will be described with reference to the drawings. Note that the drawings based on the embodiments and modification examples in the following description are schematic, and the relationship between the thickness and width of each part and the ratio of the thickness of each part may be different from the actual situation. It should be noted that there are also parts where the dimensional relationship and ratio are different between the drawings.

[0020] Also, here, in the description of the components shown in the drawings, terms such as "front", "back", "plane", "bottom surface", "side surface", etc. in the orthographic projection method are used, but they are based on the up, down, left, and right directions when looking at the drawing paper, and the direction of the component itself is not defined.

[0021] FIG. 1 is a plan view showing an example of the configuration of a film antenna according to an embodiment. FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1.

[0022] The film antenna 1 is configured by disposing a conductive antenna body on a base material, for example, having electrical insulation and flexibility, formed in an arc shape. Specifically, the antenna structure of the present embodiment is one in which the film antenna 1 is curved and disposed in an arc shape (C shape). Note that the film antenna 1 is not limited to being curved and disposed in an arc shape (C shape), and as will be described later, it includes various disposition forms.

[0023] As shown in Figures 1 and 2, the film antenna 1 consists of an electrically insulating resin film 11 which is the base material, and a folded dipole antenna 12 which is the antenna body formed on the resin film 11.

[0024] The resin film 11 has a first surface S1 on which the folded dipole antenna 12 is formed, and a second surface S2 opposite to the first surface S1. This resin film 11 is rectangular in shape and is made of a flexible sheet-like member. However, the shape of the resin film 11 is not limited to a rectangular shape and may be other shapes. Furthermore, the material of the resin film 11 is not particularly limited and can be, for example, polyester, polyethylene, polypropylene, acrylic, polyvinyl chloride, polyethylene terephthalate (PET), polyimide, etc., but other materials may be used as long as they have electrical insulating properties.

[0025] The folded dipole antenna 12 is composed of a conductor (first conductive path) 12a, a conductor (second conductive path) 12b, and a conductor (third conductive path) 12c. The conductors 12a to 12c are antenna elements formed from metal or metal foil. The materials for the conductors 12a to 12c can be, for example, gold, silver, copper, iron, nickel, aluminum, or alloys mainly composed of these materials, but other materials that are conductive can also be used, such as indium tin oxide (ITO) or indium zinc oxide (IZO). In the case of the film antenna 1, the folded dipole antenna 12 is formed on a resin film 11, but it is not limited to this, and for example, a dipole antenna or other antennas may be formed on the resin film 11.

[0026] The conductors 12a to 12c that constitute the folded dipole antenna 12 are formed on the first surface S1 of the resin film 11. The method for forming the conductors 12a to 12c on the resin film 11 is not particularly limited, and for example, vapor deposition, sputtering, etching, electrodeposition, or printing can be used.

[0027] Conductors 12a and 12b each have a length of λ / 4 when the wavelength of the transmitted radio wave is λ, and are arranged on the same straight line, resulting in a total length of λ / 2. Conductor 12c is arranged parallel to conductors 12a and 12b and has a length of λ / 2. The parallel spacing between conductors 12a and 12b and conductor 12c is set appropriately according to the transmission frequency.

[0028] Furthermore, the lengths of the conductors 12a and 12b are not limited to λ / 4, but may be less than λ / 4 (for example, λ / 4 × 0.8). Similarly, the length of the conductor 12c is not limited to λ / 2, but may be less than λ / 2 (for example, λ / 2 × 0.8). In this way, by making the lengths of the conductors 12a and 12b less than λ / 4 and the length of the conductor 12c less than λ / 2, the film antenna 1 can be miniaturized.

[0029] One end of each of the conductors 12a and 12b is connected to a feed line 13 that constitutes an antenna cable. The other ends of the conductors 12a and 12b are connected to the ends of a parallel conductor 12c.

[0030] One end of the power supply line 13 is connected to one end of the conductors 12a and 12b, respectively. The other end of the power supply line 13 is electrically connected to a wireless communication unit provided on a circuit board (not shown).

[0031] The folded dipole antenna 12 functions as a folded dipole antenna when it is supplied with alternating current via the feed line 13. Specifically, alternating current is supplied to the folded dipole antenna 12 via the feed line 13 from a wireless communication unit provided on a circuit board (not shown), and transmission data is transmitted from the folded dipole antenna 12.

[0032] As shown in Figure 2, the film antenna 1 has a folded dipole antenna 12 formed on the first surface S1 of the resin film 11. However, the configuration is not limited to this, and other configurations such as the one shown in Figure 3 may also be used. Figure 3 is a cross-sectional view showing another example of the film antenna configuration.

[0033] As shown in Figure 3, the film antenna 1A has a folded dipole antenna 12 formed on the resin film 11 such that the first surface S1 of the resin film 11 and the upper surfaces of the conductors 12a to 12c that form the folded dipole antenna 12 are on the same plane. In other words, the film antenna 1A is formed by providing grooves in the resin film 11 for forming the conductors 12a to 12c, and embedding the conductors 12a to 12c in these grooves.

[0034] The film antenna 1 (or 1A) configured in this way is curved in an arc shape, as shown in Figure 4, such that the first surface S1 of the resin film 11 faces outward and the second surface S2 faces inward. Figure 4 is a perspective view showing the film antenna in an arc shape.

[0035] The film antenna 1, which is curved in an arc shape as shown in Figures 5 and 6, is then installed in a housing (antenna case) to form an antenna unit. Figure 5 is an exploded perspective view showing the configuration of the antenna unit. Figure 6 is a cross-sectional view showing the configuration of the antenna unit.

[0036] As shown in Figures 5 and 6, the antenna unit 30 includes a film antenna 1, an antenna case 31, and an antenna cover 32. However, the shape of the antenna unit 30 is not limited to the shapes shown in Figures 5 and 6. Furthermore, the antenna unit 30 does not necessarily have to have an antenna cover 32.

[0037] The antenna case 31 has a substantially cylindrical case body 31a. The case body 31a has a fitting hole 31b formed in the center. A circuit board (not shown) to which the feed line 13 is connected is disposed in the fitting hole 31b. As a result, alternating current is supplied from the wireless communication unit provided on the circuit board to the folded dipole antenna 12 via the feed line 13.

[0038] The case body 31a has an antenna mounting groove 31c formed around the circumference from the flat surface toward the thicker part. The antenna mounting groove 31c is a substantially circular groove. The antenna mounting groove 31c communicates with a cable insertion passage 31d that opens on the flat side of the case body 31a.

[0039] The power supply line 13 is inserted through the cable insertion passage 31d. This connects the power supply line 13 to a circuit board (not shown) located in the mating hole 31b.

[0040] The case body 31a has four locking grooves 31e on its outer circumference. It goes without saying that the number of locking grooves 31e is not limited to four. Each locking groove 31e is a roughly L-shaped recess formed along the circumferential direction, extending from the flat edge of the case body 31a towards the bottom surface.

[0041] The antenna cover 32 has a cover body 32a that is formed in a substantially annular shape. The cover body 32a has an inwardly flange-shaped top surface portion 32b on its planar side. The top surface portion 32b has an opening 32c that is hollowed out in a substantially circular shape in the center. That is, the top surface portion 32b has a ring plate shape.

[0042] The cover body 32a has four locking protrusions 32d formed on its inner circumferential wall. The number of locking protrusions 32d is not limited to four, but can be adjusted to match the number, position, and shape of the locking grooves 31e. These four locking protrusions 32d are formed at approximately equal intervals in the circumferential direction of the case body 31a.

[0043] When the antenna cover 32 is attached to the antenna case 31, each locking projection 32d of the cover body 32a engages with each locking groove 31e of the case body 31a. When the antenna cover 32 is rotated, each locking projection 32d that engages with each locking groove 31e slides in the circumferential direction and locks in place. In this way, the antenna cover 32 is fixed in place so that it does not come off the antenna case 31.

[0044] The film antenna 1 is curved in an arc shape and placed in the antenna mounting groove 31c of the antenna case 31. At this time, the film antenna 1 is fixed to the radially inward side surface that forms the antenna mounting groove 31c by adhesive, double-sided tape, etc. After the film antenna 1 is installed in the antenna mounting groove 31c, a filler material 33a such as epoxy resin, polyurethane resin, or silicone resin is injected into the antenna mounting groove 31c.

[0045] Therefore, the film antenna 1 is protected and kept airtight and / or at least watertight by being covered with the filler material 33a.

[0046] In this way, because the film antenna 1 is curved in an arc shape and placed in the antenna installation groove 31c, which is a circumferential groove, the installation space can be reduced compared to, for example, placing a dipole antenna 12 in a straight line in the antenna case 31.

[0047] Although the film antenna 1 has an arc-shaped, specifically C-shaped, antenna structure as shown in Figure 4, it is not limited to such an antenna structure, and various antenna structures as shown in Figure 7 may also be used. Figure 7 shows a modified example of the antenna structure of the film antenna.

[0048] The film antenna 1 may have an L-shaped antenna structure, as shown in Figure 7(a). Alternatively, the film antenna 1 may have a roughly circular (roughly O-shaped) antenna structure, as shown in Figure 7(b).

[0049] Furthermore, the film antenna 1 may have a C-shaped antenna structure with a bent portion, as shown in Figures 7(c) to 7(h). Specifically, the film antenna 1 may have an antenna structure in which a part of one side of a rectangle is missing, as shown in Figure 7(c). Also, the film antenna 1 may have an antenna structure in which one side of a rectangle is missing, as shown in Figure 7(d). Furthermore, the film antenna 1 may have an antenna structure in which a part of two adjacent sides of a rectangle (rhombuse) is missing, as shown in Figure 7(e).

[0050] Furthermore, the film antenna 1 may have an antenna structure in which parts of two adjacent sides of a hexagon are missing, as shown in Figure 7(f). Also, the film antenna 1 may have an antenna structure in which two adjacent sides of a hexagon are missing, as shown in Figure 7(g). Furthermore, the film antenna 1 may have an antenna structure in which parts of two adjacent sides of a decagon are missing, as shown in Figure 7(h).

[0051] Furthermore, the film antenna 1 of this embodiment is not limited to the antenna structure shown in Figures 4 and 7(a) to 7(h), but may have any shape in which part or all of the antenna is curved and / or bent in three dimensions. The antenna mounting groove 31c in which the film antenna 1 is installed is not limited to a substantially circular shape, but may have any shape that matches the shape of the film antenna 1.

[0052] Furthermore, when positioning the film antenna 1 in the antenna mounting groove 31c, as shown in Figure 8, the second surface S2 of the resin film 11, where the conductive parts 12a to 12c are not formed, may be adhered or fixed to the inner side surface forming the antenna mounting groove 31c using an adhesive layer 14 such as adhesive or double-sided tape. The film antenna 1 may have an adhesive layer 14 formed by attaching a release sheet to its back surface (the second surface S2 of the resin film 11), and may be configured to be attachable to a desired surface. By peeling off the release sheet, the adhesive layer 14 on the back surface can be attached to the desired surface. Figure 8 is an enlarged view of area B in Figure 6, and is a cross-sectional view showing an example of the configuration of a transmitting antenna placed in the antenna mounting groove.

[0053] In this case, after the film antenna 1 is installed in the antenna installation groove 31c, a filler material 33a such as epoxy resin, polyurethane resin, or silicone resin may be injected. As a result, the film antenna 1 is covered with the filler material 33a, ensuring that it is airtight and / or at least watertight, and also being reinforced in terms of strength.

[0054] Furthermore, the configuration of the film antenna 1 placed in the antenna mounting groove 31c is not limited to the configuration shown in Figure 8, but may also be the configurations shown in Figures 9 to 11. Figures 9 to 11 are cross-sectional views showing other examples of the configuration of the transmitting antenna placed in the antenna mounting groove.

[0055] As shown in Figure 9, instead of the film antenna 1, the film antenna 1A shown in Figure 3 may be used, which is formed by embedding a folded dipole antenna 12 in a resin film 11. The film antenna 1A is curved in an arc shape such that the first surface S1 of the resin film 11 is on the outside and the second surface S2 is on the inside. The film antenna 1A can then be bonded or fixed to the inner side surface circumferentially on the second surface S2, which is opposite to the first surface S1 on which the folded dipole antenna 12 is formed, by using an adhesive layer 14 such as adhesive or double-sided tape to form the antenna mounting groove 31c.

[0056] Furthermore, as shown in Figure 10, the film antenna 1 may be positioned so that the first surface S1 on which the conductors 12a to 12c of the folded dipole antenna 12 are formed faces the inner side surface of the antenna mounting groove 31c. That is, the film antenna 1 is curved in an arc shape so that the first surface S1 of the resin film 11 faces inward and the second surface S2 faces outward. The first surface S1 on which the conductors 12a to 12c of the resin film 11 are formed may be bonded or fixed to the inner side surface forming the antenna mounting groove 31c using an adhesive layer 14.

[0057] Furthermore, as shown in Figure 11, the film antenna 1A may be positioned so that the first surface S1 on which the conductors 12a to 12c of the folded dipole antenna 12 are formed faces the inner side surface of the antenna mounting groove 31c. That is, the film antenna 1A is curved in an arc shape so that the first surface S1 of the resin film 11 faces inward and the second surface S2 faces outward. Then, similar to the configuration in Figure 10, the first surface S1 on which the conductors 12a to 12c of the resin film 11 are formed can be bonded or fixed to the inner side surface forming the antenna mounting groove 31c using the adhesive layer 14.

[0058] According to the configuration shown in Figures 10 and 11, the resin film 11 functions as a protective member that protects the folded dipole antenna 12. Therefore, according to the configuration in Figures 10 and 11, the folded dipole antenna 12 is protected by the resin film 11 and the adhesive layer 14. After installing the film antenna 1 or 1A in the antenna installation groove 31c, the filler material 33a may or may not be injected.

[0059] As described above, in this embodiment, the film antenna 1 is curved in an arc shape and can be placed in the antenna mounting groove 31c, which is a substantially circular circumferential groove, thus saving space in the structure of the antenna unit 30. By saving space in the antenna unit 30, the housing in which the antenna unit 30 is installed can also be made more space-saving, which in turn reduces the manufacturing cost of the device equipped with it.

[0060] Therefore, with the film antenna of this embodiment, the manufacturing cost of the device equipped with it can be reduced without increasing the size of the housing in which the antenna is installed.

[0061] The components of the embodiments described above can be combined with each other insofar as they do not contradict each other, and various modifications can be made without departing from the spirit of the present invention. Furthermore, the above embodiments include inventions of various stages, and various inventions can be extracted by appropriate combinations of the multiple components disclosed.

[0062] For example, if the problem described can be solved and the effects described can be obtained even if some of the constituent elements shown in the embodiment are deleted, then the configuration with the deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0063] 1.1A~1C Film Antenna 11 Resin film 12. Folded Dipole Antenna 12a~12c Conductor 13 Power line 14 Adhesive layer 30 Antenna Units 31 Antenna Case 31a Case body 31b Fitting hole 31c Antenna mounting groove 31d Cable insertion passage 31e Locking groove 31f Cable entry passage 32 Antenna cover 32a Cover body 32b Top section 32c opening 32d Locking protrusion 33a Filler

Claims

1. A substrate having electrical insulating properties, The antenna body is formed on the first surface of the above substrate, An antenna structure characterized in that the above-mentioned base material and the above-mentioned antenna body are partially or entirely three-dimensionally curved and / or bent.

2. The antenna body comprises a first conductive path formed on the first surface of the substrate, A second conductive path formed on the first surface of the substrate in the same straight line as the first conductive path, A third conductive path is formed on the first surface of the substrate, parallel to the first conductive path and the second conductive path, and having a length approximately equal to the combined length of the first conductive path and the second conductive path. The antenna structure according to claim 1, characterized by comprising the above.

3. The antenna structure according to claim 2, characterized in that the substrate, the first conductive path, the second conductive path, and the third conductive path are curved and / or bent such that the first surface is on the outside and the second surface opposite to the first surface is on the inside.

4. The antenna structure according to claim 2, characterized in that the substrate, the first conductive path, the second conductive path, and the third conductive path are curved and / or bent such that the first surface is on the inside and the second surface opposite to the first surface is on the outside.

5. The antenna structure according to claim 2, characterized in that the first conductive path, the second conductive path, and the third conductive path are formed to be embedded in the substrate.

6. The antenna structure according to claim 2, characterized in that one end of the first conductive path and the second conductive path are connected to a power supply line through which alternating current is supplied, and the other end of each is connected to the end of the third conductive path.

7. The antenna structure according to claim 1, characterized in that the antenna comprising the substrate and the antenna body is a film antenna.

8. The antenna structure according to claim 7, characterized in that the film antenna is partially or entirely curved and / or bent in three dimensions to match the shape of the object.

9. The antenna structure according to claim 8, characterized in that the film antenna has an adhesive layer formed by attaching a release sheet to its back surface, and is configured to be attachable to a desired surface.

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