WO2023242887A1

WO2023242887A1 - Antenna device

Info

Publication number: WO2023242887A1
Application number: PCT/JP2022/023560
Authority: WO
Inventors: 拓弥宮坂; 真悟山浦; 研悟西本
Original assignee: 三菱電機株式会社
Priority date: 2022-06-13
Filing date: 2022-06-13
Publication date: 2023-12-21
Also published as: JPWO2023242887A1; TW202349791A

Abstract

The present invention comprises: a liquid crystal display (13) having a conductive thin film (131, 132); a metal housing (11) with the liquid crystal display (13) built into one side; a GND electrode (15) that is disposed to face the one side of the metal housing (11) with a gap therebetween; and an antenna conductor (14) that allows visible light to pass therethrough, is disposed in the same plane as the GND electrode (15) with a gap therebetween, and covers the liquid crystal display (13). The antenna conductor (14) has: a first gap portion (145) that is provided on the inside of the antenna conductor (14) on the reverse side from the GND electrode (15) side; and a second gap portion (146) that communicates with the first gap portion (145) and is provided on the outer periphery of the antenna conductor (14) on the reverse side from the GND electrode (15) side. The thin film (131, 132) does not face the gap between the GND electrode (15) and the antenna conductor (14) and does not face the first gap portion (145).

Description

antenna device

The present disclosure relates to an antenna device in which an antenna conductor capable of transmitting visible light is mounted on a liquid crystal display.

In recent years, the development of transparent antennas, which are antenna conductors using transparent conductive materials with high transmittance to visible light, has progressed. In this transparent antenna, a transparent conductive film is formed on a base material such as glass, making it possible to mount the antenna while maintaining invisibility.

The conductivity of the transparent conductive material used in this transparent antenna decreases as the light transmittance increases. For example, in the case of a conductive material with high transmittance, its conductivity is about 1/100 that of copper, aluminum, or the like. That is, in transparent conductive materials, there is a trade-off relationship between light transmittance and electrical conductivity.
Therefore, in this transparent antenna, when a conductive material having a high transmittance for visible light is used to improve non-visibility, there is a problem that radiation efficiency decreases.

Therefore, in order to solve this problem, a method has been proposed in which a GND electrode is provided with a gap between the metal casing and power is supplied to the gap between the transparent antenna and the GND electrode (for example, the patent (See Reference 1). Here, the GND electrode is capacitively coupled to a metal casing that is larger in size than the GND electrode, so that current also flows through the metal casing. This makes it possible to suppress the concentration of current to the transparent antenna and prevent the radiation efficiency of the transparent antenna from decreasing.

International Publication No. 2018/235260

On the other hand, when a transparent antenna is mounted on a liquid crystal display, an indium tin oxide film (hereinafter referred to as "ITO film") is present directly under the transparent antenna.
In this case, when current flows through the transparent antenna, current also flows through the ITO film due to capacitive coupling between the transparent antenna and the ITO film. Furthermore, since the ITO film has a large resistance value, loss in the ITO film increases, resulting in a problem in that the radiation efficiency of the transparent antenna decreases.
Another problem with conventional transparent antennas is that it is not possible to change the frequency at which the radiation efficiency becomes high.

The present disclosure has been made to solve the above-mentioned problems, and even when an antenna conductor capable of transmitting visible light is arranged on a liquid crystal display, it is possible to prevent a decrease in radiation efficiency compared to the conventional method, Another object of the present invention is to provide an antenna device that can adjust the frequency at which the radiation efficiency becomes high.

An antenna device according to the present disclosure includes a liquid crystal display having a conductive thin film, a metal casing with a built-in liquid crystal display on one side, and a GND electrode placed facing the one side of the metal casing with a gap therebetween. and an antenna conductor capable of transmitting visible light, disposed on the same plane as the GND electrode with a gap therebetween, and covering the liquid crystal display, the antenna conductor being provided on the inside opposite to the GND electrode side. and a second gap portion communicating with the first gap portion and provided on the outer periphery on the opposite side to the GND electrode side, and the thin film is formed between the GND electrode and the antenna conductor. , and do not face the first gap.

According to the present disclosure, with the above configuration, even when an antenna conductor capable of transmitting visible light is arranged on a liquid crystal display, a decrease in radiation efficiency can be prevented and the radiation efficiency can be improved compared to the conventional art. It becomes possible to adjust the increasing frequency.

1 is a perspective view showing a configuration example of an antenna device according to Embodiment 1. FIG. FIG. 2 is a perspective view showing a configuration example of a metal casing in Embodiment 1. FIG. 3 is a diagram showing an example of the configuration of the back side of the protective glass in Embodiment 1. FIG. FIG. 2 is a top view showing a configuration example of the antenna device according to Embodiment 1, with the protective glass removed. 1 is an exploded perspective view showing a configuration example of a liquid crystal device in Embodiment 1. FIG. FIG. 2 is a top view showing a configuration example of the antenna device according to Embodiment 1, showing only a metal housing, a first ITO film, and a first glass. FIG. 2 is a top view showing a configuration example of the antenna device according to Embodiment 1, showing only a metal housing, an antenna conductor, and a first ITO film. 1 is a cross-sectional view showing a configuration example of an antenna device according to Embodiment 1. FIG. FIG. 2 is a top view showing a configuration example of the antenna device according to Embodiment 1, and is a diagram illustrating an image of magnetic current generated in the antenna device. 1 is a cross-sectional view showing a configuration example of an antenna device according to Embodiment 1, including a magnetic current generated in the antenna device. FIG. FIG. 2 is a top view showing a configuration example of the antenna device according to Embodiment 1 in which the antenna conductor is changed to a monopole antenna. 12 is a graph showing an example of frequency characteristics of radiation efficiency in the antenna device according to Embodiment 1 and the antenna device shown in FIG. 11. FIG. 7 is a graph showing an example of frequency characteristics of radiation efficiency when changing the length of the second gap in the antenna device according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of the antenna device according to Embodiment 1, with a first L-shaped element and a second L-shaped element removed from the antenna conductor. 15 is a graph showing an example of frequency characteristics of radiation efficiency when changing the length of the large-area antenna shown in FIG. 14. FIG. FIG. 7 is a top view showing a configuration example of an antenna device according to Embodiment 2, showing only a metal housing, an antenna conductor, and a first ITO film. FIG. 7 is a diagram illustrating an image of magnetic current generated in the antenna device according to Embodiment 2. FIG. FIG. 7 is a top view showing another configuration example of the antenna device according to Embodiment 2, showing only the metal casing, the antenna conductor, and the first ITO film. FIG. 7 is a top view showing another configuration example of the antenna device according to Embodiment 2, showing only the metal casing, the antenna conductor, and the first ITO film. FIG. 7 is a top view showing a configuration example of an antenna device according to Embodiment 3, showing only a metal casing, an antenna conductor, and a first ITO film. FIG. 12 is a perspective view showing a configuration example of the vicinity of the power feeding section in the antenna device according to Embodiment 4, with the metal casing removed. FIG. 12 is a top view showing a configuration example of the vicinity of the power feeding unit in the antenna device according to Embodiment 4, with the metal casing and the feeding rigid board removed. 23A and 23B are diagrams showing a configuration example of a rigid board for power feeding in Embodiment 4, in which FIG. 23A is a diagram showing the front surface, and FIG. 23B is a diagram showing the back surface. FIG. 7 is a cross-sectional view showing a configuration example of an antenna device according to a fourth embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
Embodiment 1.
FIG. 1 is a perspective view showing a configuration example of an antenna device 1 according to the first embodiment.
The antenna device 1 is a device in which an antenna conductor 14 that can transmit visible light is mounted on a liquid crystal device (liquid crystal display) 13. As shown in FIG. 1, this antenna device 1 includes a metal housing 11 and a protective glass 12.

The metal casing 11 is a metal casing in which a liquid crystal device 13 is built in on one side (the top side in FIG. 1). This metal casing 11 has an opening on one side. Note that the opening surface of the metal housing 11 is not shown in FIG. 1 because the protective glass 12 exists directly above it.

FIG. 2 is a perspective view showing a configuration example of the metal casing 11 in the first embodiment.
As shown in FIG. 2, the metal housing 11 has a dimension in the x direction of Cx, a dimension in the y direction of Cy, and a dimension of the z direction of Cz. Further, the metal housing 11 has an open surface on one surface in the +z direction. Further, the metal housing 11 has bezels 111 to 114 having a width of Cb at the edge of the opening surface. Therefore, the area of the opening surface is {(Cx-2*Cb)*(Cy-2*Cb)}. Further, the metal casing 11 has metal walls 115 to 118 on the side surfaces and a metal plate 119 on the bottom surface.

The protective glass 12 is a glass for protecting the liquid crystal device 13 built into the metal casing 11 located directly below.
Note that the user visually recognizes the liquid crystal device 13 from the +z direction with respect to the protective glass 12.

FIG. 3 is a diagram showing an example of the configuration of the back surface of the protective glass 12 in the first embodiment, and FIG. 4 is a top view showing an example of the configuration of the antenna device 1 according to the first embodiment. Note that FIG. 4 shows a state in which the protective glass 12 has been removed.
As shown in FIGS. 3 and 4, an antenna conductor 14 and a GND electrode 15 are mounted on the back surface of the protective glass 12. Further, a power feeding section 16 is arranged between the gap between the antenna conductor 14 and the GND electrode 15. Then, by applying AC power to this power feeding section 16, the antenna conductor 14 is excited. That is, of the feed line (not shown) wired from the user interface (not shown) of the liquid crystal device 13, the signal line side is connected to the antenna conductor 14, and the GND side is connected to the GND electrode 15.

The antenna conductor 14 is a conductor that can transmit visible light, is disposed on the same (substantially the same meaning) plane as the GND electrode 15, and covers the liquid crystal device 13 with a gap therebetween. The antenna conductor 14 is made of a transparent conductive material that can transmit visible light. Here, an example will be described in which the antenna conductor 14 is a transparent conductive film and has a rectangular shape.
As shown in FIG. 4, this antenna conductor 14 includes a transmission line 141, a large area antenna 142, a first L-shaped element 143, and a second L-shaped element 144.

The transmission line 141 is a straight line with one end facing the GND electrode 15 with a gap therebetween, and the other end connected to the large area antenna 142. This transmission line 141 is a line for transmitting the power excited by the power feeding section 16 to the large area antenna 142, the first L-shaped element 143, and the second L-shaped element 144.

The large-area antenna 142 is a planar conductor arranged to cover a first ITO film 131 and a second ITO film 132, which will be described later, in the liquid crystal device 13. Further, this large-area antenna 142 also partially covers the

bezels

112 and 114 of the metal housing 11.

The first L-shaped element 143 is an L-shaped conductor that is in contact with one of both sides of the large-area antenna 142. This first L-shaped element 143 has a first linear line portion 1431 and a second linear line portion 1432. The first linear line portion 1431 is in contact with one of both side surfaces of the large area antenna 142. In FIG. 1, the first linear line portion 1431 is in contact with the left side of the large-area antenna 142. Further, the second linear line portion 1432 is not in contact with the large-area antenna 142, and one end thereof is in contact with the end of the first linear line portion 1431.

Note that the width of the first L-shaped element 143 is the same (including substantially the same meaning) as the width of the

bezels

112 and 113 in the metal housing 11. The first L-shaped element 143 is arranged so as to overlap the

bezels

112 and 113 in the metal housing 11.
In FIG. 4, the first L-shaped element 143 overlaps a portion of the bezel 112 and a portion of the bezel 113. In FIG.

The second L-shaped element 144 is an L-shaped conductor that is in contact with the other of both sides of the large-area antenna 142. This second L-shaped element 144 has a first linear line portion 1441 and a second linear line portion 1442. The first straight line portion 1441 is in contact with the other side of both sides of the large area antenna 142. In FIG. 1, the first linear line portion 1441 is in contact with the right side of the large area antenna 142. Further, the second linear line portion 1442 is not in contact with the large-area antenna 142, and one end thereof is in contact with the end of the first linear line portion 1441.

Note that the width of the second L-shaped element 144 is the same (including substantially the same meaning) as the width of the

bezels

114 and 113 in the metal housing 11. The second L-shaped element 144 is arranged so as to overlap the

bezels

114 and 113 in the metal housing 11.
In FIG. 4, second L-shaped element 144 overlaps a portion of bezel 114 and a portion of bezel 113. In FIG.

The first L-shaped element 143 and the second L-shaped element 144 are arranged line-symmetrically with respect to the x-axis.

Note that, as shown in FIG. It is configured by providing two gap portions 146.
The first gap portion 145 is a gap provided inside the antenna conductor 14 on the side opposite to the GND electrode 15 side. In FIG. 3, the first gap 145 has a rectangular shape.
The second gap 146 communicates with the first gap 145 and is a gap provided on the outer periphery of the antenna conductor 14 on the side opposite to the GND electrode 15 side. The width of the second gap portion 146 is configured to be shorter than the width of the first gap portion 145.

Note that a slight gap is left in the portion where the antenna conductor 14 and the metal casing 11 face each other. That is, the antenna conductor 14 is not in contact with the metal housing 11.

Further, in the above description, the first L-shaped element 143 overlaps a portion of the bezel 112 and a portion of the bezel 113. However, the present invention is not limited thereto, and the first L-shaped element 143 may not overlap the bezel 112 and the bezel 113.
Furthermore, in the above description, the second L-shaped element 144 overlaps a portion of the bezel 114 and a portion of the bezel 113. However, the present invention is not limited thereto, and the second L-shaped element 144 may not overlap the bezel 114 and the bezel 113.

The GND electrode 15 is a linear electrode placed facing one surface (opening surface) of the metal casing 11 with a gap provided therebetween. That is, the GND electrode 15 is not in contact with the metal casing 11. Further, as shown in FIG. 4, most of the GND electrode 15 is disposed directly above and opposite to the bezel 111 of the metal housing 11 with a gap therebetween.

Note that the GND electrode 15 has an insufficient size as a GND size. However, this GND electrode 15 is capacitively coupled with the bezel 111 of the metal casing 11 directly below, and the metal casing 11 is also used as a GND, thereby ensuring a sufficient GND size.

Furthermore, it is also possible to directly connect the power supply section 16 to the metal casing 11 without using the GND electrode 15. However, in this case, the structure becomes complicated and power supply becomes difficult, so capacitive coupling using the GND electrode 15 can more easily supply power.

Note that FIGS. 3 and 4 show a case where the GND electrode 15 is configured line-symmetrically with respect to the x-axis. However, the present invention is not limited to this, and the GND electrode 15 may not be configured line-symmetrically with respect to the x-axis.

Further, FIG. 4 shows a case where the power feeding unit 16 is arranged at the center (including the meaning of approximately the center) in the y direction (side of the bezel 111). However, the present invention is not limited to this, and the power feeding section 16 may not be arranged at the center of the side of the bezel 111.

FIG. 5 is an exploded perspective view showing a configuration example of the liquid crystal device 13 in the first embodiment.
The liquid crystal device 13 has a first ITO film 131, a second ITO film 132, a first glass 133, and a second glass 134, as shown in FIG. As shown in FIG. 5, the liquid crystal device 13 includes a first ITO film 131, a first glass 133, a second ITO film 132, and a second glass 134 stacked in this order from the +z direction.

The first ITO film 131 is mounted on one surface (the upper surface in FIG. 5) of the first glass 133. Further, the second ITO film 132 is mounted on the other surface (the lower surface in FIG. 5) of the first glass 133. Note that in FIG. 5, the first ITO film 131, the second ITO film 132, and the first glass 133 are shown separated for ease of viewing.
Further, here, an example will be described in which the first ITO film 131 and the second ITO film 132 are configured in a rectangular shape.

The first ITO film 131 and the second ITO film 132 have a high sheet resistance value. For example, the sheet resistance values are, for example, 50Ω/□ and 31Ω/□. Therefore, if the antenna conductor 14 is placed directly above the first ITO film 131 and the second ITO film 132 and a current flows on the antenna conductor 14, the antenna conductor 14 and the first ITO film 131 and the second ITO film 132 are capacitively coupled. In this case, current also flows through the first ITO film 131 and the second ITO film 132, resulting in loss, leading to a reduction in the radiation efficiency of the antenna conductor 14.

Note that only four members, the first ITO film 131, the second ITO film 132, the first glass 133, and the second glass 134, are shown here as the constituent elements of the liquid crystal device 13; In reality, there are many more parts included.

FIG. 6 is a top view showing a configuration example of the antenna device 1 according to the first embodiment, and shows only the metal housing 11, the first ITO film 131, and the first glass 133.
As shown in FIG. 6, the first glass 133 has a dimension in the x direction of (Cx-2*Cb) and a dimension in the y direction of (Cy-2*Cb). That is, the first glass 133 has the same size (including substantially the same meaning) as the opening surface of the metal housing 11. Therefore, the first glass 133 exactly overlaps the opening surface of the metal housing 11.
Although the second glass 134 is not shown in FIG. 6 because it cannot be seen when viewed from directly above, it is the same size (including approximately the same meaning) as the first glass 133, and is directly above the second glass 134. The positional relationship when viewed from above is also the same as that of the first glass 133.

Further, the first ITO film 131 is arranged at a distance of Dm from the edge of the bezels 111 to 114 of the metal housing 11. Therefore, the area of the first ITO film 131 is {(Cx-2*Cb-2*Dm)*(Cy-2*Cb-2*Dm)}.
Although the second ITO film 132 is not shown in FIG. 6 because it is not visible when viewed from directly above, it has the same size (including substantially the same meaning) as the first ITO film 131, The positional relationship seen from directly above is also the same as that of the first ITO film 131.

FIG. 7 is a top view showing a configuration example of the antenna device 1 according to the first embodiment. Note that in FIG. 7, the protective glass 12 is removed, and only the first ITO film 131 is shown as the liquid crystal device 13.
As shown in FIG. 7, the large area antenna 142 has a dimension in the x direction of (Cx-2*Cb-2*Dm), which is the same (approximately) as the first ITO film 131 and the second ITO film 132. (with the same meaning). Therefore, the large-area antenna 142, the first ITO film 131, and the second ITO film 132 exactly overlap on the x-axis.
Further, the large area antenna 142 has a dimension in the y direction of Cy, and is designed to cover the

bezels

112 and 114 of the metal housing 11.

That is, in the antenna device 1 according to the first embodiment, the first ITO film 131 and the second ITO film 132 are arranged between the GND electrode 15 and the antenna conductor 14 and in the first gap 145. Not facing each other.

FIG. 8 is a sectional view taken along the line aa' of the antenna device 1 shown in FIG.
As shown in FIG. 8, the GND electrode 15 is capacitively coupled to the bezel 111 in the metal housing 11, and current is passed through the metal housing 11 as well, thereby ensuring GND. At this time, the smaller the distance DC between the protective glass 12 and the metal housing 11, the closer the distance between the GND electrode 15 and the bezel 111 in the metal housing 11 becomes, and thus the amount of coupling increases.

Next, the effects of the antenna device 1 according to the first embodiment configured as described above will be explained.
First, the arrangement of the wave sources that prevents the radiation efficiency of the antenna device 1 from decreasing will be explained.
FIG. 9 shows a radiated magnetic current source formed by a current flowing through the antenna conductor 14 in the antenna device 1 according to the first embodiment. Note that FIG. 9 shows a state in which the protective glass 12 has been removed.
As shown in FIG. 9, when power is excited to the antenna conductor 14 by the power feeding section 16, a current flows on the antenna conductor 14. At this time, the large-area antenna 142 operates as a patch antenna, and

magnetic currents

51a and 51b are generated in the gap (Dm). These

magnetic currents

51a and 51b serve as radiation sources, and the antenna device 1 radiates electromagnetic waves.

FIG. 10 is a sectional view taken along the line bb' shown in FIG.
As shown in FIG. 10, the first ITO film 131 and the second ITO film 132 do not exist directly under the

magnetic currents

51a and 51b generated in the gap (Dm). Therefore, in the antenna device 1 according to the first embodiment, the current flowing through the first ITO film 131 and the second ITO film 132 can be suppressed, and the radiation efficiency of the antenna device 1 can be prevented from decreasing, compared to the conventional method. becomes.

FIG. 11 is a top view showing a configuration example of the antenna device 1 according to the first embodiment in which the antenna conductor 14 is changed to a monopole antenna 21. Note that FIG. 11 shows a state in which the protective glass 12 has been removed.
As shown in FIG. 11, in the monopole antenna 21, the current 51c flowing on the monopole antenna 21 directly serves as a radiation source. In this case, the first ITO film 131 and the second ITO film 132 exist directly under the current 51c. Therefore, in this case, a strong current flows also in the first ITO film 131 and the second ITO film 132, leading to a decrease in the radiation efficiency of the antenna device 1b.

FIG. 12 is a diagram showing an example of frequency characteristics of radiation efficiency in the antenna device 1 according to the first embodiment and the configuration shown in FIG. 11. Note that the radiation efficiency shown in FIG. 12 does not take into account mismatch loss, and shows the case where it is normalized at the reference frequency (f0). In FIG. 12, a solid line indicates an example of the frequency characteristic of radiation efficiency in the case of the antenna device 1 according to the first embodiment, and a broken line indicates an example of the frequency characteristic of radiation efficiency in the configuration shown in FIG. 11.
As shown in FIG. 12, it can be confirmed that the radiation efficiency of the antenna device 1 according to the first embodiment is higher than that of the configuration shown in FIG. 11.

Next, a method of changing the frequency at which the radiation efficiency becomes high in the antenna device 1 according to the first embodiment will be described.
In the antenna device 1 according to the first embodiment, as shown in FIG. 9, in the antenna conductor 14, the tip of the first L-shaped element 143 and the tip of the second L-shaped element 144 are separated from each other. A gap 146 is provided. In the antenna device 1 according to the first embodiment, by adjusting the length Ls of the second gap 146, the length of the first L-shaped element 143 and the second L-shaped element 144 can be adjusted. The current path length changes, and the magnetic current length of the magnetic current 51a can be adjusted. As a result, in the antenna device 1 according to the first embodiment, it is possible to adjust the frequency at which the radiation efficiency becomes high.

FIG. 13 is a diagram showing an example of the frequency characteristics of radiation efficiency when Ls, which is the length of the second gap 146, is changed in the first embodiment. Note that the radiation efficiency shown in FIG. 13 does not take mismatch loss into consideration.
Note that, as shown in FIG. 7, Ls takes a maximum value of Cy.
As shown in FIG. 13, two frequencies with high radiation efficiency appear except for the case where Ls=Cy. In this way, the antenna device 1 according to the first embodiment has a wide adjustable range of frequencies where the radiation efficiency is high.

Note that when Ls=Cy, the first L-shaped element 143 and the second L-shaped element 144 are not present, and only the large-area antenna 142 is present. Therefore, the current distributions forming the

magnetic currents

51a and 51b are symmetrical. As a result, the two

magnetic currents

51a and 51b become like a patch antenna that operates at a single frequency, and the radiation efficiency becomes high only at one frequency, approximately f0.

FIG. 14 is a diagram showing a configuration example in the case where the first L-shaped element 143 and the second L-shaped element 144 are removed from the antenna device 1 according to the first embodiment. Note that FIG. 14 shows a state in which the protective glass 12 has been removed.
As shown in FIG. 14, as a system in which the frequency can be adjusted, the first L-shaped element 143 and the second L-shaped element 144 are removed from the antenna conductor 14, and the length of the large-area antenna 142 in the x direction is One possible method is to change La. From FIG. 6, the maximum value of La is Cx-2*Cb-2*Dm. Here, for convenience, it is assumed that Lax=Cx-2*Cb-2*Dm.

FIG. 15 is a diagram showing an example of frequency characteristics when La is changed in the configuration shown in FIG. 14. Note that the radiation efficiency shown in FIG. 15 does not take mismatch loss into consideration.
As shown in Fig. 15, the frequency at which the radiation efficiency increases is changing, but compared to Fig. 13, the adjustable range is smaller and the amount of reduction in radiation efficiency (the amount of efficiency reduction) is also larger. I understand.

Here, it is assumed that a frequency variable amount defined by the following formula (1) is used as an index indicating how much the frequency can be adjusted.
Frequency variable amount = variable amount of frequency that increases radiation efficiency / lowest frequency among frequencies that increases radiation efficiency (1)

In this case, in the antenna device 1 according to Embodiment 1, the amount of frequency variation is 55%, and in the configuration shown in FIG. 14, the amount of frequency variation is 20%. Therefore, it can be seen that the antenna device 1 according to the first embodiment can obtain about 2.5 times the amount of frequency variation as compared to the configuration shown in FIG. 14.
Further, in the antenna device 1 according to the first embodiment, the efficiency decrease amount is 2.9 dB, and in the configuration shown in FIG. 14, the efficiency decrease amount is 4.5 dB. Therefore, it can be seen that the antenna device 1 according to the first embodiment suppresses the efficiency drop by 1.6 dB compared to the configuration shown in FIG. 14.

As described above, according to the first embodiment, the antenna device 1 includes the liquid crystal device 13 having the first ITO film 131 and the second ITO film 132, and the metal device 13 having the liquid crystal device 13 built-in on one side. A casing 11 and a GND electrode 15 which is disposed facing each other with a gap between them on one surface of the metal casing 11, and a GND electrode 15 which can transmit visible light and which is disposed on the same plane as the GND electrode 15 with a gap between them. An antenna conductor 14 that covers the liquid crystal device 13 is provided, and the antenna conductor 14 communicates with a first gap 145 provided on the inside opposite to the GND electrode 15 side, and communicates with the first gap 145 and connects the GND electrode The first ITO film 131 and the second ITO film 132 are provided between the GND electrode 15 and the antenna conductor 14, and a second gap 146 provided on the outer periphery on the opposite side to the , are not opposed to the first gap portion 145. As a result, the antenna device 1 according to the first embodiment prevents a decrease in radiation efficiency compared to the conventional art even when the antenna conductor 14 capable of transmitting visible light is disposed on the liquid crystal device 13, and It becomes possible to adjust the frequency at which efficiency is high.

Embodiment 2.
FIG. 16 is a top view showing a configuration example of the antenna device 1 according to the second embodiment. Note that FIG. 16 shows a state in which the protective glass 12 has been removed.
In the antenna device 1 according to the second embodiment shown in FIG. 16, the configuration of the large area antenna 142 is changed from the antenna device 1 according to the first embodiment. The other configuration example of the antenna device 1 according to the second embodiment shown in FIG. 16 is the same as the configuration example of the antenna device 1 according to the first embodiment, and only the different parts will be described with the same reference numerals. conduct.

A large area antenna 142 in the second embodiment shown in FIG. 16 has a cutout in a portion not facing the first ITO film 131 and the second ITO film 132, compared to the large area antenna 142 in the first embodiment. It has a built-in structure. That is, the first gap 145 in the second embodiment is configured to have a bent shape within the plane of the antenna conductor 14.

Here, the large area antenna 142 in the first embodiment has a dimension in the x direction of (Cx-2*Cb-2*Dm), and the first ITO film 131 and the second ITO film 132 in the x direction. It is the same as the size (including the meaning of approximately the same). Therefore, this large-area antenna 142 exactly overlaps the first ITO film 131 and the second ITO film 132, and is covered by both the first ITO film 131 and the second ITO film 132 as well as the large-area antenna 142. There were parts that weren't there. In the antenna device 1 according to the first embodiment, the principle of a patch antenna is based on the rectangular portion of the large-area antenna 142 that exists on the first ITO film 131 and the second ITO film 132. It is considered that

currents

51a and 51b are generated and radiate electromagnetic waves.

On the other hand, in the second embodiment, a cutout is made in a portion of the large-area antenna 142 that does not overlap the first ITO film 131 and the second ITO film 132. As a result, in the antenna device 1 according to the second embodiment, the antenna device 1 according to the first embodiment is covered with both the first ITO film 131 and the second ITO film 132 and the large-area antenna 142. The missing part will be increased.

FIG. 17 is a diagram showing the magnetic current generated in the configuration shown in FIG. 16.
Even if the portion not covered by the first ITO film 131, the second ITO film 132, or the large area antenna 142 increases, the principle of the patch antenna remains the same. Therefore, as shown in FIG. 17, the magnetic current generated in the antenna device 1 according to the second embodiment is the same as that in the antenna device 1 according to the first embodiment. Therefore, the effects obtained with the antenna device 1 according to the second embodiment are the same as the effects obtained with the antenna device 1 according to the first embodiment.

Further, FIGS. 18 and 19 are top views showing another configuration example of the antenna device 1 according to the second embodiment. Note that FIGS. 18 and 19 show a state in which the protective glass 12 is removed.
FIG. 16 shows a case where cutouts are provided at both ends of the large area antenna 142. In FIG. However, the present invention is not limited to this. For example, as shown in FIG. 18, the notch may be provided only at one end (the left side in FIG. 18), or, for example, as shown in FIG. 19, the notch may be provided at both ends. The lengths of the parts provided may be different from each other. Even with this configuration, the same effects as above can be obtained.

Therefore, according to the antenna device 1 of the second embodiment, the large area antenna 142 has a structure in which a cutout is made in a portion that does not overlap the first ITO film 131 and the second ITO film 132. However, the same effects as those of the antenna device 1 according to the first embodiment can be obtained.

Embodiment 3.
FIG. 20 is a top view showing a configuration example of the antenna device 1 according to the third embodiment. Note that FIG. 20 shows a state in which the protective glass 12 has been removed.
In the antenna device 1 according to the third embodiment shown in FIG. 20, the configuration of the antenna conductor 14 is changed from the antenna device 1 according to the first embodiment. The other configuration example of the antenna device 1 according to the third embodiment shown in FIG. 20 is the same as the configuration example of the antenna device 1 according to the first embodiment, and the same reference numerals are given and only different parts will be explained. conduct.

As shown in FIG. 20, in contrast to the antenna conductor 14 in Embodiment 1, in the antenna conductor 14 in the third embodiment, the part covering the metal housing 11 (bezels 112 to 114) is different from the part covering the liquid crystal device 13. It is constructed using a material with high conductivity. Note that, as a material having high electrical conductivity for the portion covering the liquid crystal device 13, for example, a solid silver film or a copper foil can be used. In FIG. 20, a portion of the antenna conductor 14 made of a material with high conductivity is shown in a different color from the other portions.

Here, since the bezels 111 to 114 portions of the metal housing 11 are not display portions of the liquid crystal device 13, the antenna conductor 14 does not need to be transparent.
Therefore, as shown in FIG. 20, by using a non-transparent but highly conductive material for the part of the antenna conductor 14 that faces the above-mentioned part, the antenna device 1 according to the first embodiment On the other hand, further improvement in radiation efficiency is expected.

As described above, according to the antenna device 1 of the third embodiment, by using a highly conductive material such as a solid silver film for the portion of the antenna conductor 14 where the bezels 111 to 114 overlap, The radiation efficiency is further increased compared to the antenna device 1 according to No. 1.

Note that in the above, a case has been shown in which the configuration of the antenna conductor 14 is changed in the antenna device 1 according to the first embodiment. However, the present invention is not limited to this, and the configuration of the antenna conductor 14 may be changed in the antenna device 1 according to the second embodiment, and the same effects as described above can be obtained.

Embodiment 4.
FIG. 21 is a perspective view showing a configuration example of a power feeding portion of the antenna device 1 according to the fourth embodiment. Note that FIG. 21 shows a state in which the metal casing 11 is removed.
In the antenna device 1 according to the fourth embodiment shown in FIG. 21, the configuration of the power feeding section 16 is changed from the antenna device 1 according to the first embodiment. The other configuration example of the antenna device 1 according to the fourth embodiment shown in FIG. 21 is the same as the configuration example of the antenna device 1 according to the first embodiment, and the same reference numerals are given and only different parts will be explained. conduct.

In the power feeding section 16 in the fourth embodiment, a rigid power feeding board 161 is provided.
The power feeding rigid board 161 is a board for feeding power, which is placed opposite to the GND electrode 15 and the antenna conductor 14 at a location other than the location overlapping with the opening surface of the metal housing 11. The power feeding rigid board 161 is assumed to be a dielectric board made of resin such as FR-4 with copper foil mounted on both sides, but is not limited thereto.

FIG. 22 is a diagram showing an example of an arrangement location of the power feeding rigid board 161. Moreover, FIG. 23 is a diagram showing an example of the configuration of the power feeding rigid board 161. Further, FIG. 24 is a cross-sectional view showing a configuration example of the antenna device 1 according to the fourth embodiment.
As shown in FIGS. 22 to 24, a conductive pattern is printed on the power feeding rigid board 161. This conductor pattern is designed so that when the feeding rigid board 161 is placed on the transmission line 141 and the GND electrode 15 in the antenna conductor 14, it is traced exactly to the part facing the transmission line 141 and the GND electrode 15. It is a conductor pattern formed in Note that the location indicated by the reference numeral 221 in FIG. 22 is the location where the power feeding rigid board 161 is arranged.

That is, the power feeding rigid board 161 has a conductor pattern 1611 traced on the transmission line 141 side and a conductor pattern 1612 traced on the GND electrode 15 side as conductor patterns.

Note that in the power feeding rigid board 161, a conductive pattern 1611 and a conductive pattern 1612 are printed on the front and back surfaces, respectively.
In addition, in the power feeding rigid board 161, the conductor pattern 1611 formed on the front surface is electrically connected to the conductor pattern 1611 formed on the back surface through a through hole (not shown), and the conductor pattern 1612 formed on the front surface is electrically connected to the conductor pattern 1611 formed on the back surface. It is electrically connected to the conductive pattern 1612 through a through hole (not shown).

22, the rigid board for power feeding 161 is electrically connected to the transmission line 141 via the conductor pattern 1611, and the GND electrode 15 and the conductor are connected to each other. Conductivity is established through the pattern 1612.

Further, in the power supply rigid board 161, a power supply signal line (not shown) is connected to a surface not in contact with the transmission line 141 and the GND electrode 15 side, and is connected to a user interface of the liquid crystal device 13, etc.
Further, by providing a matching circuit on the signal line connection side of the feeding rigid board 161, it is possible to easily match the impedance of the antenna.

Note that the power feeding rigid board 161 may be arranged so as to be in physical contact with the transmission line 141 and the GND electrode 15, or may be arranged with a gap therebetween.
Further, the conductor pattern on the power feeding rigid board 161 may be different between the front and back surfaces, and the conductor pattern may also have an arbitrary shape.

As described above, according to the antenna device 1 of the fourth embodiment, by using the feeding rigid board 161, power can be fed by simply arranging the board. This results in a simpler power supply structure.

Note that the above describes a case where the configuration of the power feeding section 16 is changed in the antenna device 1 according to the first embodiment. However, the present invention is not limited to this, and the configuration of the power feeding section 16 may be changed in the antenna device 1 according to the second and third embodiments, and the same effects as described above can be obtained.

Note that in Embodiments 1 to 4, the case where the antenna conductor 14 is a transparent conductive film has been described as an example. However, the present invention is not limited thereto, and the antenna conductor 14 may be any conductor as long as it can transmit visible light.　　　

Furthermore, in Embodiments 1 to 4, the case where the liquid crystal device 13 has the first ITO film 131 and the second ITO film 132 has been described as an example. However, the present invention is not limited to this, and even if the liquid crystal device 13 has a conductive thin film other than an ITO film, the same effects as described above can be obtained by adopting the configurations shown in Embodiments 1 to 4. It will be done.

Furthermore, in Embodiments 1 to 4, the case where the first ITO film 131, the second ITO film 132, and the antenna conductor 14 were configured in a rectangular shape was explained as an example. However, the shapes of the first ITO film 131, the second ITO film 132, and the antenna conductor 14 are not limited to this, and can be changed as appropriate.

Note that it is possible to freely combine each embodiment, to modify any component of each embodiment, or to omit any component in each embodiment.

The antenna device according to the present disclosure can prevent a decrease in radiation efficiency and adjust the frequency at which the radiation efficiency becomes higher than before even when an antenna conductor that can transmit visible light is arranged on a liquid crystal display. Therefore, it is suitable for use in an antenna device or the like in which an antenna conductor capable of transmitting visible light is mounted on a liquid crystal display.

1 antenna device, 11 metal housing, 12 protective glass, 13 liquid crystal device (liquid crystal display), 14 antenna conductor, 15 GND electrode, 16 power feeding section, 21 monopole antenna, 51a, 51b magnetic current, 51c current, 111-114 Bezel, 115-118 Metal wall, 119 Metal plate, 131 First ITO film, 132 Second ITO film, 133 First glass, 134 Second glass, 141 Transmission line, 142 Large area antenna, 143 First L-shaped element, 144 second L-shaped element, 145 first gap part, 146 second gap part, 161 power feeding rigid board, 1431 first straight line part, 1432 second straight line part Line part, 1441 First straight line part, 1442 Second straight line part, 1611 Conductor pattern, 1612 Conductor pattern.

Claims

a liquid crystal display having a conductive thin film;
a metal casing with the liquid crystal display built-in on one side;
a GND electrode disposed opposite to one surface of the metal casing with a gap therebetween;
an antenna conductor capable of transmitting visible light, disposed on the same plane as the GND electrode with a gap therebetween, and covering the liquid crystal display;
The antenna conductor is
a first gap provided on the inside opposite to the GND electrode side;
a second gap part communicating with the first gap part and provided on the outer periphery on the opposite side to the GND electrode side;
The antenna device, wherein the thin film does not face between the GND electrode and the antenna conductor and does not face the first gap.
The antenna device according to claim 1, wherein the antenna conductor is made of a transparent conductive material that can transmit visible light.
The antenna device according to claim 1 or 2, wherein the first gap portion is configured to have a bent shape within a plane of the antenna conductor.
The antenna device according to any one of claims 1 to 3, wherein the antenna conductor partially covers the metal casing.
The antenna device according to any one of claims 1 to 4, wherein the thin film and the antenna conductor are configured in a rectangular shape.
5. The antenna device according to claim 4, wherein a portion of the antenna conductor that covers the metal casing is made of a material having higher conductivity than a portion that covers the liquid crystal display.
The antenna device according to any one of claims 1 to 6, further comprising a power feeding rigid board that is arranged to face the GND electrode and the antenna conductor and feeds power.
It is characterized by comprising a power feeding section that is provided between the GND electrode and the antenna conductor at the center in a direction perpendicular to the direction connecting the GND electrode and the antenna conductor, and that feeds power. An antenna device according to any one of claims 1 to 6.
The antenna device according to any one of claims 1 to 8, wherein the GND electrode is configured line symmetrically with respect to a direction connecting the GND electrode and the antenna conductor.