Radio wave reflection plate, radio wave reflection device, and method for driving radio wave reflection device

Abstract

This radio wave reflection plate comprises a plurality of reflection elements, a first signal line that extends in a first direction and that supplies a control signal which includes a potential corresponding to a phase of a reflected radio wave, and a second signal line that extends in a second direction which intersects the first direction and that supplies a scanning signal, wherein: the plurality of reflection elements each include a patch electrode, a conductive layer that is disposed so as to be separated from the patch electrode along a third direction which intersects the first direction and the second direction and that faces the patch electrode, a liquid crystal layer that is disposed between the patch electrode and the conductive layer, and a switching element that is connected to the first signal line and the second signal line and that electrically connects the patch electrode and the first signal line on the basis of the control signal; and, among the plurality of reflection elements, at least two reflection elements adjacent to each other along the first direction are connected to the same first signal line and the same second signal line.

Description

Radio wave reflector, radio wave reflection device, and driving method for radio wave reflection device

[0001] One embodiment of the present invention relates to a radio wave reflector capable of controlling the traveling direction of reflected radio waves. One embodiment of the present invention also relates to a radio wave reflection device capable of controlling the traveling direction of reflected radio waves. One embodiment of the present invention also relates to a driving method for a radio wave reflection device capable of controlling the traveling direction of reflected radio waves.

[0002] A Phased Array Antenna device includes a metasurface including a plurality of antenna elements arranged in a planar shape. When a signal including an electric potential corresponding to a predetermined phase is applied to each of the plurality of antenna elements, the metasurface can control the directivity of the antenna while each of the plurality of antenna elements is in a fixed state. As a result, a high-frequency device including the metasurface can change the transmission direction of radio waves to avoid obstacles and expand the communication area.

[0003] For example, Patent Documents 1 and 2 disclose a metasurface that utilizes a change in dielectric constant caused by the alignment state of liquid crystals by adjusting the amplitude and phase of a signal applied to each of a plurality of antenna elements.

[0004] Japanese Unexamined Patent Application Publication No. 11-103201 Japanese National Publication of International Patent Application No. 2019-530387

[0005] For example, high-frequency millimeter-wave band radio waves (24 GHz to 29 GHz) are used in high-speed large-capacity communication of 5th generation communication (5G). High-frequency radio waves have high straightness and a short reach. Therefore, in an area where buildings and the like stand densely, high-frequency radio waves are blocked, and the communication quality of high-frequency radio waves decreases. For example, when a radio wave reflector that includes a plurality of antenna elements (reflective elements) and can reflect radio waves is installed near an area where radio waves are difficult to reach, the radio wave reflector can reflect radio waves into the area where radio waves are difficult to reach, thereby improving communication quality in such an area. Furthermore, a radio wave reflector with a larger reflective surface can reflect radio waves more efficiently.

[0006] Therefore, in order to improve communication quality over a wider area and more efficiently in areas where radio waves have difficulty reaching, a radio wave reflector with a large reflective surface size, i.e., a large radio wave reflector, is required. Generally, the size of an antenna element is determined by the frequency of a predetermined radio wave reflected by the antenna element, i.e., the wavelength of a predetermined radio wave. Therefore, if the size of the antenna element is changed, it becomes difficult to incident on and reflect the predetermined radio wave. Thus, it is difficult to easily change the size of the antenna element in a radio wave reflector. Furthermore, in large radio wave reflectors, since the size of the antenna element cannot be easily changed, it is necessary to place antenna elements in the area where the size of the radio wave reflector has increased. As a result, a large radio wave reflector includes a large number of antenna elements, a large number of wires for electrically connecting the large number of antenna elements, and a large number of wires for electrically connecting the large number of antenna elements to a drive circuit for driving the large number of antenna elements. Thus, the peripheral area (e.g., the frame area) within the radio wave reflector where a large number of wires are placed increases, and the parasitic capacitance and wiring resistance increase with the increase in wiring, increasing the load required to drive the large radio wave reflector. Furthermore, as the peripheral area within a large radio wave reflector increases, the probability of radio waves being reflected by areas other than the antenna element increases, resulting in an increase in so-called unwanted reflections and thus a decrease in the efficiency of radio wave reflection.

[0007] In view of these problems, one embodiment of the present invention aims to provide a radio wave reflector capable of suppressing the increase in the surrounding area. Another embodiment of the present invention aims to provide a radio wave reflecting device capable of suppressing the increase in the surrounding area. Yet another embodiment of the present invention aims to provide a driving method for a radio wave reflecting device capable of controlling the propagation direction of reflected radio waves.

[0008] A radio wave reflector according to one embodiment of the present invention includes a plurality of reflecting elements, a first signal line extending in a first direction and supplying a control signal including a potential corresponding to the phase of the reflected radio wave, and a second signal line extending in a second direction intersecting the first direction and supplying a scanning signal, wherein each of the plurality of reflecting elements includes a patch electrode, a conductive layer disposed at a distance from the patch electrode along a third direction intersecting the first and second directions and facing the patch electrode, a liquid crystal layer disposed between the patch electrode and the conductive layer, and a switching element connected to the first signal line and the second signal line and electrically connecting the patch electrode and the first signal line based on the control signal, wherein at least two adjacent reflecting elements along the first direction are connected to the same first signal line and the same second signal line.

[0009] A method for driving a radio wave reflector according to one embodiment of the present invention includes a plurality of reflector elements, a first signal line extending in a first direction and supplying a control signal including a potential corresponding to the phase of the reflected radio wave, and a second signal line extending in a second direction intersecting the first direction and supplying a scanning signal, wherein each of the plurality of reflector elements includes a patch electrode, a conductive layer disposed at a distance from the patch electrode along a third direction intersecting the first and second directions and facing the patch electrode, a liquid crystal layer disposed between the patch electrode and the conductive layer, and a switching element connected to the first signal line and the second signal line and electrically connecting the patch electrode and the first signal line based on the control signal, wherein the plurality A method for driving a radio wave reflector, comprising: a radio wave reflector having at least two adjacent reflectors among a plurality of reflectors connected to the same first signal line and the same second signal line, and a control circuit electrically connected to the first signal line and the second signal line, which supplies a control signal to the first signal line including a potential corresponding to the phase of the reflected radio wave and supplies the scanning signal to the second signal line, wherein the driving method includes supplying the control signal to the first signal line connected to at least two of the plurality of reflectors, supplying the scanning signal to the second signal line connected to the two reflectors, and reflecting the reflected radio wave at a predetermined reflection angle.

[0010] This is a plan view showing the configuration of the radio wave reflector according to the first embodiment. This is a circuit diagram showing the circuit configuration of the reflecting element according to the first embodiment. This is a plan view showing an example of the layout of the radio wave reflector according to the first embodiment. This is a plan view showing an example of the layout of the reflecting element shown in Figure 3. This is a diagram for explaining the state in which no voltage is applied between the patch electrode and the conductive layer of the reflecting element according to the first embodiment. This is a diagram for explaining the state in which a control signal is applied to the patch electrode of the reflecting element according to the first embodiment. This is a diagram for explaining the state in which a control signal is applied to the patch electrode of the reflecting element according to the first embodiment. This is a diagram showing an example of the relationship between the liquid crystal applied voltage supplied to the reflecting element according to the first embodiment and its relative phase. This is a diagram showing an example of a timing chart for explaining the driving method of the radio wave reflector according to the first embodiment. This is a diagram showing an example of the arrangement of patch electrodes and the equivalent phase plane in a comparative example. This is a diagram showing an example of the arrangement of patch electrodes and the equivalent phase plane in the radio wave reflector according to the first embodiment. This is a diagram showing the relationship between element number and element position in the radio wave reflector according to a comparative example, and the relationship between element number and center position according to the first embodiment. This is a diagram showing the relationship between element number and center position in the radio wave reflector according to the second embodiment. This is a plot diagram showing an example of the relationship between the center position and relative phase of bundled reflecting elements in the radio wave reflector according to the second embodiment. This is a plot diagram showing the simulation results of the radio wave reflector shown in Figure 14. This is a diagram showing the relationship between element number and center position in the radio wave reflector according to the third embodiment. This is a plot diagram showing an example of the relationship between the center position and relative phase of bundled reflecting elements in the radio wave reflector according to the third embodiment. This is a plot diagram showing the simulation results of the radio wave reflector according to the third embodiment.

[0011] The embodiments of the present invention will be described below with reference to the drawings. However, the present invention can be implemented in many different ways, and is not limited to the embodiments described below. In order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each drawing, elements similar to those described above with respect to previously shown drawings are denoted by the same reference numerals (or numerals followed by a, b, etc.) to omit redundant explanations. Furthermore, the letters "First," "Second," etc., attached to each element are convenient indicators used to distinguish each element and have no further meaning unless specifically explained.

[0012] In this specification, when a member or region is said to be "above (or below)" another member or region, unless otherwise specified, this includes not only cases where it is directly above (or directly below) the other member or region, but also cases where it is above (or below) the other member or region, that is, cases where another component is included between them above (or below) the other member or region.

[0013] In the specification of this application, the first direction D1 intersects the second direction D2, and the third direction D3 intersects the first direction D1 and the second direction D2 (directions corresponding to the normal direction to the D1D2 plane). For example, the first direction D1, the second direction D2, and the third direction D3 correspond to the X direction, the Y direction, and the Z direction.

[0014] In the specification of this application, when the terms identical, same, and consistent are used, the terms identical and consistent may include errors within the scope of the design.

[0015] <First Embodiment> <1-1. Overview of the Radio Wave Reflector 100> An overview of the radio wave reflector 100 will be described with reference to Figure 1. Figure 1 is a plan view showing the configuration of the radio wave reflector 100. The radio wave reflector 100 is a device that can control the direction of propagation of reflected radio waves using a metasurface (reflector 120) that utilizes the change in dielectric constant due to the orientation state of liquid crystal. The reflector or radio wave reflector may be denoted as IRS (INTELLIGENT REFLEECTING SURFACE), or as IRD (INTELLIGENT REFLEECTING DEVICE).

[0016] The radio wave reflector 100 includes an IC chip 130 and a reflector 120, and has a configuration that allows for biaxial reflection control. The reflector 120 includes a plurality of reflective elements 102 arranged in a matrix in a first direction D1 and a second direction D2. For example, the plurality of reflective elements 102 extending in the first direction D1 are arranged in the row direction, and the plurality of reflective elements 102 extending in the second direction D2 are arranged in the column direction. For example, the radio wave reflector 100 shown in Figure 1 includes 16 reflective elements 102 in a 4x4 arrangement. The number of elements in the radio wave reflector 100 shown in Figure 1 is just an example, and the number of reflective elements 102 is not limited to 16.

[0017] For example, the plurality of reflective elements 102 includes reflective elements 102a to 102h. As will be described in detail later, each of the plurality of reflective elements 102 includes a circuit 103 for driving the reflective element 102, a patch electrode 108 (see Figure 2), a conductive layer 110 (see Figure 2) that is opposite to and spaced apart from the patch electrode 108, and a liquid crystal layer 114 (see Figure 5) provided between the patch electrode 108 and the conductive layer 110. Note that the circuit 103 may include the patch electrode 108 and the conductive layer 110. The size of each patch electrode 108 of the plurality of reflective elements 102 is the same.

[0018] Furthermore, each of the multiple reflective elements 102 (circuit 103) is electrically connected to the corresponding first signal line 118, the corresponding second signal line 132, and the corresponding common wiring 113. Each patch electrode 108 of the multiple reflective elements 102 is electrically connected to the corresponding first signal line 118, and each conductive layer 110 of the multiple reflective elements 102 is electrically connected to the corresponding common wiring 113.

[0019] The IC chip 130 is connected to a plurality of first connection signal lines 119, a plurality of second connection signal lines 133, and a common wiring 113. More specifically, the IC chip 130 includes a first drive circuit 130a and a second drive circuit 130b. The first drive circuit 130a is connected to a plurality of first connection signal lines 119, and the second drive circuit 130b is connected to a plurality of second connection signal lines 133. The first drive circuit 130a is a so-called source driver (signal line drive circuit), and the second drive circuit 130b is a so-called gate driver (scan line drive circuit).

[0020] For example, multiple first connection signal lines 119 include first connection signal lines 119a and 119b. Each of the multiple first connection signal lines 119 is connected to multiple first signal lines 118. For example, multiple first signal lines 118 include first signal lines 118a to 118d, first signal lines 118a and 118b are connected to first connection signal line 119a, and first signal lines 118c and 118d are connected to first connection signal line 119b. In other words, the first connection signal line 119 branches into multiple first signal lines 118. To put it another way, the first connection signal line 119 bundles together multiple first signal lines 118.

[0021] For example, similar to the multiple first connection signal lines 119, the multiple second connection signal lines 133 include second connection signal lines 133a and 133b. Each of the multiple second connection signal lines 133 is connected to a plurality of second signal lines 132. For example, the plurality of second signal lines 132 include second signal lines 132a to 132d, with second signal lines 132a and 132b being connected to second connection signal line 133a, and second signal lines 132c and 132d being connected to second connection signal line 133b. In other words, the second connection signal line 133 branches into a plurality of second signal lines 132. To put it another way, the second connection signal line 133 bundles together a plurality of second signal lines 132.

[0022] The radio wave reflector 100 includes, as an example, a configuration in which the first connection signal line 119 is branched into two first signal lines 118, and the second connection signal line 133 is branched into two second signal lines 132. The configurations of the first connection signal line 119, the first signal line 118, the second connection signal line 133, and the second signal line 132 in the radio wave reflector 100 are not limited to those shown herein. For example, the first connection signal line 119 may be branched into three or more first signal lines 118, and the second connection signal line 133 may be branched into three second signal lines 132. The configurations of the first connection signal line 119, the first signal line 118, the second connection signal line 133, and the second signal line 132 in the radio wave reflector 100 may be appropriately adjusted according to the application, specifications, etc. of the radio wave reflector 100.

[0023] The first drive circuit 130a outputs a control signal SS to the first connection signal line 119 and a plurality of first signal lines 118 connected to the first connection signal line 119. The second drive circuit 130b outputs a scan signal SG to the second connection signal line 133 and a plurality of second signal lines 132 connected to the second connection signal line 133. The IC chip 130 outputs a common signal SC to the common wiring 113. The plurality of control signals SS include control signals SS(1) to SS(m / k), and the plurality of scan signals SG include scan signals SG(1) to SG(n / k). For example, the numerical value k is an integer greater than or equal to 2 and is a divisor of the numerical values ​​m and n.

[0024] The IC chip 130 can control the reflector 120, which includes multiple reflective elements 102 (circuits 103), by supplying signals to each of the multiple reflective elements 102 (circuits 103) to drive them. For example, the signals that drive the multiple reflective elements 102 (circuits 103) are the scanning signal SG, the control signal SS, the common signal SC, etc.

[0025] In the radio wave reflector 100, the patch electrode 108 and the conductive layer 110 may be referred to as the first electrode and the second electrode, the IC chip 130 may be referred to as the control circuit, the first drive circuit 130a and the second drive circuit 130b may be referred to collectively as the control circuit, the first drive circuit 130a may be referred to as the control circuit by itself, and the second drive circuit 130b may be referred to as the control circuit by itself.

[0026] Furthermore, in the radio wave reflector 100, when it is necessary to distinguish between multiple reflecting elements, the multiple reflecting elements are referred to as multiple reflecting elements 102a to 102h, and when it is not necessary to distinguish between multiple radio wave reflecting unit cells, the multiple reflecting elements are referred to as multiple reflecting elements 102. Similar to multiple reflecting elements, the notation for multiple first connection signal lines, multiple first signal lines, multiple control signals, multiple second connection signal lines, multiple second signal lines, multiple scanning signals, patch electrodes 108, conductive layers 110, and reflecting element groups 202 may also change depending on whether they are distinguished or not. Furthermore, multiple first connection signal lines 119 may be denoted as first connection signal lines 119(1) to 119(m / k), multiple control signals may be denoted as first control signal SS(1) to the m / k control signal SS(m / k), multiple second connection signal lines may be denoted as second connection signal lines 133(1) to 133(n / k), and multiple scanning signals may be denoted as first scanning signal SG(1) to the n / k scanning signal SG(n / k). Note that first connection signal lines 119(1) and 119(2) correspond to first connection signal lines 119a and 119b, and second connection signal lines 133(1) and 133(2) correspond to second connection signal lines 133a and 133b.

[0027] For example, reflective element 102a is connected to the first connection signal line 119a and the first signal line 118a, and the second connection signal line 133a and the second signal line 132a; reflective element 102b is connected to the first connection signal line 119a and the first signal line 118b, and the second connection signal line 133a and the second signal line 132a; reflective element 102e is connected to the first connection signal line 119a and the first signal line 118a, and the second connection signal line 133a and the second signal line 132b; and reflective element 102f is connected to the first connection signal line 119a and the first signal line 118b, and the second connection signal line 133a and the second signal line 132b. As a result, reflective elements 102a, 102b, 102e, and 102f are supplied with the same control signal SS(1) and scanning signal SG(1).

[0028] In other words, two reflective elements 102, reflective elements 102a and 102b, can be considered to be bundled together, and a set of reflective elements 202a can be considered to be supplied with the same control signal SS(1) and scanning signal SG(1). Similarly, two reflective elements 102, reflective elements 102c and 102d, can be considered to be bundled together, and a set of reflective elements 202b can be considered to be supplied with the same control signal SS(2) and scanning signal SG(1). Furthermore, four reflective elements 102, namely 102a, 102b, 102e, and 102f, can be bundled together to form a group of reflective elements 202a, which can be considered to be supplied with the same control signal SS(1) and scanning signal SG(1). Similarly, four reflective elements 102, namely 102c, 102d, 102g, and 102h, can be bundled together to form a group of reflective elements 202b, which can be considered to be supplied with the same control signal SS(2) and scanning signal SG(1).

[0029] Therefore, the radio wave reflector 100 includes a configuration in which multiple first signal lines are bundled together by a first connecting signal line, multiple second signal lines are bundled together by a second connecting signal line, and wiring arranged within the reflector 120 is bundled together by a common wiring 113 and routed to the surrounding area 122. As a result, the radio wave reflector 100 (reflector 120) can reduce the number of wires routed to the surrounding area 122 compared to the case where unbundled wiring is routed to the surrounding area 122, and can suppress an increase in the area of ​​the surrounding area 122.

[0030] Furthermore, the radio wave reflector 100 includes multiple reflective element groups 202, each to which multiple first signal lines are bundled together by a first connecting signal line, and multiple second signal lines are bundled together by a second connecting signal line, and to which the same signal (control signal and scanning signal) is supplied. As a result, although the apparent number of reflective elements in the radio wave reflector 100 is reduced, the area of ​​the patch electrodes to which the same signal (control signal and scanning signal) is supplied is increased, and the radio wave reflector 100 can suppress a decrease in the radio wave reflection efficiency and reflect radio waves more efficiently.

[0031] <1-2. Circuit Configuration of Reflecting Element 102> The circuit configuration of the reflecting element 102 will be explained with reference to Figure 2. Figure 2 is a schematic circuit diagram showing the configuration of the circuit 103 of the reflecting element 102 of the radio wave reflecting device 100. Configurations that are the same as or similar to those in Figure 1 will be explained as necessary.

[0032] Circuit 103 includes, for example, a transistor 160 and a liquid crystal element LCL. Transistor 160 includes a gate electrode 161, a source electrode 163, and a drain electrode 164. The gate electrode 161 is connected to a second signal line 132. The source electrode 163 is connected to a first signal line 118. The drain electrode 164 is connected to the first electrode of the liquid crystal element LCL. The first electrode of the liquid crystal element LCL is electrically connected to a patch electrode 108, and the second electrode of the liquid crystal element LCL is electrically connected to a conductive layer 110, which is connected to a common wiring 113.

[0033] The first and second electrodes of the liquid crystal element (LCL) are interchangeable. For the sake of explanation, the source electrode 163 of the radio wave reflector 100 will be referred to as the source electrode, and the drain electrode 164 as the drain electrode. However, depending on the voltage supplied (applied) to the source and drain electrodes of the transistor 160, the function of each electrode as a source and drain may be reversed. The transistor 160 may be referred to as a switching element.

[0034] The switching (on and off) of the switching element 134 is controlled by a scanning signal SG supplied to the second signal line 132. In response to the scanning signal SG, a reflective element 102 is selected, the switching element 134 of the selected reflective element 102 is turned on, the patch electrode 108 connected to the switching element 134 conducts to the first signal line 118, and an output signal SS is supplied. For example, the switching element 134 is formed from a thin-film transistor.

[0035] <1-3. An Example of Layout of Radio Wave Reflector 100 and Reflecting Element 102> An example of the layout of the radio wave reflector 100 and reflecting element 102 will be described with reference to Figures 3 and 4. Figure 3 is a plan view showing an example of the layout of the radio wave reflector 100. Figure 4 is a plan view showing an example of the layout when the reflecting element 102 is viewed from below (the side from which the radio waves are incident). Descriptions of the same or similar configurations as those in Figures 1 and 2 will be omitted, and descriptions of the same or similar configurations as those in Figures 1 and 2 may be provided as necessary.

[0036] As shown in Figure 3, the radio wave reflector 100 includes a dielectric substrate 104, a counter substrate 106, and a peripheral region 122. The counter substrate 106 is superimposed on the dielectric substrate 104, and the counter substrate 106 is bonded to the dielectric substrate 104 using a sealing material 128. The region enclosed by the counter substrate 106, the dielectric substrate 104, and the sealing material 128 includes a liquid crystal layer 114 (see Figure 4). Note that the dielectric substrate 104 may be referred to as the first substrate, and the counter substrate 106 may be referred to as the second substrate.

[0037] The area of ​​the dielectric substrate 104 other than where the dielectric substrate 104 and the opposing substrate 106 overlap is referred to as the peripheral region 122. The peripheral region 122 includes the IC chip 130 and terminal portion 126 arranged on the dielectric substrate 104. The terminal portion 126 is the area that forms connections with external circuits. For example, a flexible printed circuit (not shown) is connected to the terminal portion 126. Signals controlling the IC chip 130 are input from the flexible printed circuit to the terminal portion 126.

[0038] For example, the IC chip 130 shown in Figure 3 is placed on a dielectric substrate 104 (array layer 180 (see Figure 5)) using the COG (Chip on Glass) method. However, the configuration of the IC chip 130 is not limited to the above, and for example, the IC chip 130 may be placed on an FPC (Flexible printed circuits) to which the terminal portion 126 is connected, and may be mounted using the COF (Chip on Film, or Chip on Flexible, etc.) method.

[0039] Multiple patch electrodes 108 are arranged on the dielectric substrate 104 in a matrix in the first direction D1 and the second direction D2.

[0040] Multiple first connection signal lines 119 arranged on the dielectric substrate 104 extend in the first direction D1 and also extend into the peripheral region 122, and are connected to the IC chip 130 (first drive circuit 130a). The IC chip 130 (first drive circuit 130a) supplies control signals SS (outputs) corresponding to each of the multiple first connection signal lines 119.

[0041] Multiple first signal lines 118 arranged on the dielectric substrate 104 extend in the second direction D2 and into the peripheral region 122, and are connected to one of the multiple first connection signal lines 119, thereby electrically connecting to the IC chip 130. The multiple first signal lines 118 are supplied (output) from the IC chip 130 via one of the electrically connected multiple first connection signal lines 119, with a control signal SS corresponding to each of the multiple first signal lines 118.

[0042] For example, the first signal lines 118a and 118b are connected to the first connection signal line 119a, and the first signal lines 118c and 118d are connected to the first connection signal line 119b. That is, the first signal lines 118a and 118b are bundled together into a single wire by the first connection signal line 119a and supplied with a control signal SS(1) from the IC chip 130, and the first signal lines 118c and 118d are bundled together into a single wire by the first connection signal line 119b and supplied with a control signal SS(2) from the IC chip 130.

[0043] The plurality of second connection signal lines 133 disposed on the dielectric substrate 104 extend in the second direction D2 and are connected to the IC chip 130 (the second driving circuit 130b). The plurality of second connection signal lines 133 are supplied (output) with the scanning signal SG corresponding to each of the plurality of second signal lines 132 from the IC chip 130 (the second driving circuit 130b).

[0044] The plurality of second signal lines 132 disposed on the dielectric substrate 104 extend in the first direction D1, are connected to any one of the plurality of second connection signal lines 133, and are electrically connected to the IC chip 130. The plurality of second signal lines 132 are supplied with the scanning signal SG corresponding to each of the plurality of second signal lines 132 from the IC chip 130 via any one of the plurality of electrically connected second connection signal lines 133.

[0045] For example, the second signal lines 132a and 132b are connected to the second connection signal line 133a, and the second signal lines 132c and 132d are connected to the second connection signal line 133b. That is, the second signal lines 132a and 132b are combined (bundled) into a single wiring by the second connection signal line 133a, supplied with the scanning signal SG(1) from the IC chip 130, and the second signal lines 132c and 132d are combined (bundled) into a single wiring by the second connection signal line 133b, supplied with the scanning signal SG(2) from the IC chip 130.

[0046] For example, the common wiring 113 disposed on the dielectric substrate 104 extends in the second direction D2 and extends to the peripheral region 122, and is connected to the IC chip 130. The common wiring 113 is electrically connected, via the connection portion 115, to the conductive layer 110 disposed on the counter substrate 106 at the periphery of the reflection plate 120 (for example, inside the sealing material 128 on the side opposite to the side where the second connection signal line 133 is disposed in a plan view). Note that a plurality of common wirings 113 may be disposed on the dielectric substrate 104, and the common wiring 113 may extend to the peripheral region 122 and be connected to the terminal portion 126. The common wiring 113 is supplied (output) with the common signal SC from the IC chip 130.

[0047] Furthermore, the connection portion 115 connects the switching element 136 on the dielectric substrate 104 and the conductive layer 110 on the counter substrate 106. Therefore, the connection portion 115 is formed by penetrating or removing the alignment film 112a on the dielectric substrate 104 side (see FIG. 4) and the alignment film 112b on the counter substrate 106 side (see FIG. 4). For example, the connection portion 115 includes a conductive member such as a photo spacer or conductive beads. Since the liquid crystal layer 114 is disposed between the alignment film on the dielectric substrate 104 side and the alignment film on the counter substrate 106 side, the connection portion 115 in a cross-sectional view is surrounded by the liquid crystal layer 114 (see FIG. 4). Note that the connection portion 115 shown in FIG. 3 is illustrated as having the same width as the common wiring 113, but the size of the connection portion 115 can be appropriately changed according to the application or specifications of the radio wave reflection device 100, the specifications of the power-transmitting member, and the like.

[0048] The conductive layer 110 is disposed over the entire surface of the counter substrate 106 across a first direction D1 and a second direction D2. A common voltage is supplied to the conductive layer 110 from the terminal portion 126 via the common wiring 113 and the connection portion 115. For example, the common voltage may be a common voltage (voltage COM), a ground voltage (GND voltage), a 0 V voltage, or a voltage VSS.

[0049] As shown in FIG. 3 and FIG. 4, the reflective element 102 is disposed such that the conductive layer 110, the liquid crystal layer 114 (see FIG. 5), and the patch electrode 108 overlap in a plan view. The reflective element 102 includes the switching element 134.

[0050] For example, the switching element 134 is a transistor 160 (see FIG. 2) including a semiconductor layer 142a, a gate electrode 161, a source electrode 163, and a drain electrode 164. The switching element 134 is connected to the first signal line 118 via a contact hole 163a, and connected to the patch electrode 108 via a contact hole 164a. That is, the switching element 134 connects the first signal line 118 and the patch electrode 108. The conductive layer 110 is connected to the common wiring 113 (see FIG. 3) via the connection portion 115 (see FIG. 3).

[0051] The radio wave reflector 100 can control the propagation direction of reflected waves in the left-right direction of the drawing, using a reflection axis VR parallel to the second direction D2 (Y direction) as its central axis, and can also control the propagation direction of reflected waves in the up-down direction of the drawing, using a reflection axis HR parallel to the first direction D1 (X direction) as its central axis. In other words, the radio wave reflector 100 includes a reflection axis VR parallel to the second direction D2 (Y direction) and a reflection axis VH parallel to the first direction D1 (X direction), and can control the reflection angle in the direction around the reflection axis VR as the axis of rotation and in the direction around the reflection axis HR as the axis of rotation.

[0052] The patch electrodes 108 have side lengths corresponding to the frequency of the radio waves, and multiple patch electrodes 108 are formed as a rectangular collection. That is, multiple patch electrodes 108 constitute the radio wave reflection surface of the radio wave reflector 100. Furthermore, the multiple patch electrodes 108 and the conductive layer 110 are formed individually so that a potential is supplied (applied) to the liquid crystal individually to the multiple patch electrodes 108 and the conductive layer 110. The conductive layer 110 is also arranged to overlap with the patch electrodes 108.

[0053] <1-4. Overview of the operation of the reflector 120 (reflecting element 102)> The overview of the operation of the reflector 120 (reflecting element 102) will be explained with reference to Figures 5 and 6. Figure 5 is a schematic diagram showing a state in which no potential difference occurs between the patch electrode 108 and the conductive layer 110 in the reflecting element 102. Figure 6 is a diagram showing a state in which a potential difference occurs between the patch electrode 108 and the conductive layer 110 in the reflecting element 102. The explanation of configurations that are the same as or similar to those in Figures 1 to 4 will be omitted here. As will be described in detail later, the potential difference in the radio wave reflector 100 is the liquid crystal applied voltage (voltage VLC) that corresponds to the phase difference ΔΦ corresponding to the angle (reflection angle θ) at which the incident wave input to the radio wave reflector 100 is reflected, and is determined by the relationship between the liquid crystal applied voltage (voltage VLC) corresponding to the phase difference ΔΦ and the relative phase.

[0054] The radio wave reflector 100 can reflect radio waves in the direction of propagation of the reflected wave (direction of the reflection angle θ) relative to the propagation method of the incident wave by applying a voltage VLC corresponding to the phase to each group of reflecting elements 202 (multiple reflecting elements 102). There are no restrictions on the frequency of radio waves that the radio wave reflector 100 (reflecting elements 102) can reflect. For example, the frequency of radio waves that the reflecting elements 102 can reflect is 400 MHz to 300 GHz. Typically, the radio wave reflector 100 can be used to reflect radio waves in the 400 MHz to 6.0 GHz band, the 2.5 GHz to 4.7 GHz band, and the 24 GHz to 300 GHz band.

[0055] For example, one reflective element 102 includes a part of the dielectric substrate 104, a part of the array layer 180, a patch electrode 108, a part of the alignment film 112a, a part of the liquid crystal layer 114, a part of the alignment film 112b, a part of the conductive layer 110, and a part of the opposing substrate 106. Multiple reflective elements 102 share the dielectric substrate 104. The dielectric substrate 104 can be considered as a single dielectric layer. The dielectric substrate 104 is sometimes referred to as a dielectric layer.

[0056] A conductive layer 110 and common wiring 113 (see Figure 3) are provided on the first surface 106a of the opposing substrate 106. An alignment film 112b is provided on the conductive layer 110 and common wiring 113. An array layer 180 including a switching element 134 and a patch electrode 108 are provided on the first surface 104a of the dielectric substrate 104. The first surface 104a of the dielectric substrate 104 is positioned to face the first surface 106a of the opposing substrate 106. A liquid crystal layer 114 is provided between the alignment film 112a and the alignment film 112b. Although not shown in the figures, a spacer may be provided between the dielectric substrate 104 and the opposing substrate 106 to maintain a constant distance.

[0057] The reflective element 102 can change the dielectric constant of the liquid crystal layer 114 by changing the orientation state of the liquid crystal molecules 116. As a result, when the radio wave reflector 100 (reflector 120) reflects radio waves, it can delay the phase of the reflected wave.

[0058] The orientation of the liquid crystal molecules 116 in the liquid crystal layer 114 changes in response to the control signal SS supplied to the patch electrode 108 and the common signal SC supplied to the conductive layer 110, but it hardly follows the frequency of the radio waves incident on the patch electrode 108. Therefore, the reflecting element 102 can control the phase of the reflected radio waves without being affected by the incident radio waves.

[0059] Figure 5 shows a state in which no potential difference occurs between the patch electrode 108 and the conductive layer 110 (referred to as the "first state"). Figure 5 shows the case in which the alignment films 112a and 112b are horizontal alignment films. In the first state, the long axes of the liquid crystal molecules 116 are aligned horizontally with respect to the surface of the patch electrode 108 by the alignment films 112a and 112b.

[0060] Figure 6 shows the state in which the control signal SS is supplied to the patch electrode 108 (referred to as the "second state"). In the second state, for example, the liquid crystal molecules 116 are affected by the electric field and their long axes are oriented perpendicular or nearly perpendicular to the surface of the patch electrode 108. The angle at which the long axes of the liquid crystal molecules 116 are oriented can be changed according to the potential of the control signal SS supplied to the patch electrode 108 and the potential of the common signal SC supplied to the conductive layer 110. For example, the long axes of the liquid crystal molecules 116 can also be oriented in a direction intermediate between the horizontal and vertical directions.

[0061] When the liquid crystal molecules 116 have positive dielectric anisotropy, the apparent dielectric constant is higher in the second state than in the first state. Conversely, when the liquid crystal molecules 116 have negative dielectric anisotropy, the apparent dielectric constant is lower in the second state than in the first state. The liquid crystal layer 114 having dielectric anisotropy can be considered a variable dielectric layer. The reflecting element 102 can delay (or not delay) the phase of the reflected wave by utilizing the dielectric anisotropy of the liquid crystal layer 114.

[0062] <1-5. Driving Method of Radio Wave Reflector 100> The driving method of the radio wave reflector 100 will be explained with reference to Figures 7 to 9. Figure 7 is a diagram showing the state in which a voltage is supplied (applied) between the patch electrode 108 and the conductive layer 110 in the reflector element 102 used in the radio wave reflector 100. Figure 8 is a diagram to explain an example of the relationship between the voltage applied to the reflector element 102 (voltage VLC (V)) and its relative phase (deg). Figure 9 is a diagram showing an example of a timing chart to explain the driving method of the radio wave reflector 100. Explanations of configurations identical or similar to those in Figures 1 to 6 are omitted, and configurations identical or similar to those in Figures 1 to 6 may be explained as needed.

[0063] In the description of the driving method of the radio wave reflector 100 with reference to Figures 7 to 9, as an example, the driving method of the radio wave reflector 100 includes KthFRAME and K+1stFRAME. The numerical value K is a natural number greater than or equal to 1. For example, KthFRAME and K+1stFRAME each represent one frame period (1FRAME) and are referred to as the radio wave reflection period. The driving method of the radio wave reflector 100 includes the IC chip 130 outputting (supplying) a potential corresponding to the phase of each reflecting element 102 to each reflecting element 102. The driving method of the radio wave reflector 100 includes selecting a plurality of patch electrodes 108 arranged in a first direction D1 row by row during the radio wave reflection period (1FRAME). The IC chip 130 outputs (supplies) a scanning signal SG to each switching element 134 of each reflecting element 102 via the second connection signal line 133 and the second signal line 132 to select a predetermined reflecting element 102. Furthermore, the IC chip 130 outputs (supplies) a control signal SS, which includes a potential (voltage) corresponding to the phase (phase difference) according to the position of the selected reflecting element 102, to the patch electrode 108 connected to the switching element 134 of the selected reflecting element 102 via the first connection signal line 119 and the first signal line 118, so that the reflector 120 can reflect the incident wave with a predetermined reflected wave. In addition, the IC chip 130 outputs (supplies) a common signal SC to the conductive layer 110 via the common wiring 113. The IC chip 130 performs this operation row by row, and the radio wave reflector 100 can change the orientation state of the liquid crystal molecules 116 contained in the liquid crystal element LCL within the reflecting element 102 based on the potential corresponding to the phase of each reflecting element 102. As a result, the radio wave reflector 100 can reflect the incident radio waves in the desired direction.

[0064] For example, as shown in Figure 9, the control signals SS(1), SS(2), ..., SS(m / k-1) and SS(m / k) are supplied with a potential between V2 and V1, and the common signal SC is supplied with a potential COM. For example, the potential COM is a reference potential that serves as the reference for the scanning signal SG and the control signal SS, and may be an intermediate potential between potential V2 and potential V1, and may be expressed as 0V, potential VSS, or ground potential (GND potential). Also, potential V2 is a potential with the same absolute value as potential V1 but with the polarity reversed, with potential COM as the boundary, for example, potential V2 is -8V and potential V1 is +8V. Furthermore, for example, the potential difference (voltage VLC, liquid crystal applied voltage) between each patch electrode 108 of the reflective elements 102a to 102h, or the reflective element group 202 (203a, 203b, etc.) and the conductive layer 110 is supplied to the value shown in Figure 8.

[0065] For example, in the radio wave reflector 100, the ON signal may be at a high potential (High, HI) and the OFF signal may be at a low potential (Low, LO). Alternatively, in the radio wave reflector 100, the ON signal may be at a low potential and the OFF signal may be at a high potential. The high potential is greater than (higher than) the low potential. Furthermore, the high potential is greater than or equal to the maximum potential of the output signal SS and the common signal SC, and the low potential is less than or equal to the minimum potential of the output signal SS and the common signal SC.

[0066] As shown in Figure 7, the patch electrode 108a is electrically connected to the first signal line 118a and the first connection signal line 119a via the switching element 134. The switching element 134 shown in Figure 7 is electrically connected to the second signal line 132a and the second connection signal line 133a, and is turned on when the scan signal SG(1) is supplied from the IC chip 130 via the second connection signal line 133a. Therefore, the patch electrode 108a is conductive with the first signal line 118a and the first connection signal line 119a via the switching element 134, and the control signal SS(1) is supplied from the IC chip 130 via the first signal line 118a and the first connection signal line 119a. The conductive layer 110 is conductive with the common wiring 113, and the common signal SC is supplied from the IC chip 130 via the common wiring 113. The IC chip 130 outputs a scanning signal SG(1), a control signal SS(1), and a common signal SC to the reflective element 102, and a potential difference corresponding to the control signal SS(1) and the common signal SC is applied to the patch electrode 108a and the conductive layer 110a, thereby enabling the radio wave reflector 100 to reflect radio waves in the direction of the reflection angle θ.

[0067] For example, when the radio wave reflector 100 reflects an incident wave with a reflector 120 at a reflection angle θ such that the phase difference ΔΦ is 90 degrees, the IC chip 130 outputs a control signal SS to the group of reflective elements 202 (multiple reflective elements 102) that includes a voltage VLC corresponding to the element position of each reflective element group, so that the phase difference (relative phase) of adjacent reflective element groups 202 is 90 degrees.

[0068] For example, each reflective element 102 is marked with an element number n (where n is a non-negative integer) along the first direction D1, as shown in Table 1. Referring to Figure 8 and Table 1, the IC chip 130 outputs a 0V control signal SS(1) corresponding to a phase of 0 degrees to each patch electrode (108a, 108b, 108e, and 108f) of the reflective element group 202a (reflective elements 102a, 102b, 102e, and 102f), and to each patch electrode (108c, 108d, 108g, and 108h) of the reflective element group 202b (reflective elements 102a, 102b, 102e, and 102f). By outputting a 3.5V control signal SS(2) corresponding to a phase of -90 degrees, outputting a 5V control signal corresponding to a phase of -180 degrees to the group of reflective elements number 2 (not shown) adjacent to the group of reflective elements 202a along the first direction D1, and outputting a 15V control signal corresponding to a phase of -270 degrees to the group of reflective elements number 3 (not shown) adjacent to it, the radio wave reflector 100 can reflect the incident wave at a reflection angle θ.

[0069]

[0070] Referring to Figure 9, an example of how to drive the radio wave reflector 100 will be explained in more detail. For example, in the period before the KthFRAME, the IC chip 130 is supplied with the vertical retrace period control signal VSYNC. The 1FRAME of the radio wave reflector 100 is controlled by the vertical retrace period control signal VSYNC.

[0071] In KthFRAME, the IC chip 130 outputs (supplies) a common signal SC including the potential COM to the common wiring 113 and the conductive layer 110, and outputs (supplies) a scanning signal SG(1) to the second connection signal line 133a, the second signal line 132a and 132b. The IC chip 130 also outputs (supplies) a control signal SS(1) to the first connection signal line 119a, the first signal line 118a and 118b. As a result, the switching elements 134 of each of the four reflective elements 102 (reflective elements 102a, 102b, 102e, and 102f) connected to the second connection signal line 133a, the second signal lines 132a and 132b, and the first connection signal line 119a, the first signal lines 118a and 118b are turned on, and the potential included in the control signal SS(1) is supplied to the respective patch electrodes 108 of the reflective elements 102a, 102b, 102e, and 102f. In other words, the reflective elements 102a, 102b, 102e, and 102f, which are supplied with the same potential, reflect the incident wave with the same phase. Furthermore, the IC chip 130 outputs (supplies) the control signal SS(2) to the first connection signal line 119b, the first signal line 118c, and the first signal line 118d, turning on the switching element 134 of each of the four reflective elements 102 (reflective elements 102c, 102d, 102g, and 102h) connected to the first connection signal line 119b, the first signal line 118c, and the first signal line 118d, respectively, and the potential contained in the control signal SS(2) is supplied to the patch electrode 108 of each of the reflective elements 102c, 102d, 102g, and 102h. In other words, the reflective elements 102c, 102d, 102g, and 102h, which are supplied with the same potential, reflect the incident wave with the same phase. Similarly, the IC chip 130 outputs (supplies) the control signal SS(m / k-1) to the corresponding connection signal line and signal line, and the four reflective elements 102 connected to the corresponding connection signal line and signal line are supplied with the same potential and reflect the incident wave with the same phase. Similarly, the IC chip 130 outputs (supplies) the control signal SS(m / k) to the four reflective elements 102 connected to the connection signal line and signal line, and the four reflective elements 102 connected to the corresponding connection signal line and signal line are supplied with the same potential and reflect the incident wave with the same phase.

[0072] In addition, in KthFRAME, the IC chip 130 outputs (supplies) a common signal SC including potential COM to the common wiring 113 and the conductive layer 110, outputs (supplies) a scan signal SG(2) which is a shifted version of the scan signal SG(1) to the second connection signal line 133b, the second signal line 132c and 132d, and outputs (supplies) a control signal SS(1) to the first connection signal line 119a, the first signal line 118a and 118b. As a result, the switching elements 134 of each of the four reflective elements 102 (reflective elements 102c, 102d, 102g, and 102h) connected to the second connection signal line 133b, the second signal lines 132c and 132d, and the first connection signal line 119a, the first signal lines 118a and 118b are turned on, and the potential included in the control signal SS(1) is supplied to the respective patch electrodes 108 of the reflective elements 102c, 102d, 102g, and 102h. That is, the reflective elements 102c, 102d, 102g, and 102h, which are supplied with the same potential, reflect the incident wave with the same phase. Similarly, the potential contained in the control signal SS(2) is supplied to the patch electrodes 108 of each of the four reflecting elements 102 (reflecting elements 102c, 102d, 102g, and 102h) connected to the first connection signal line 119b, the first signal line 118c, and 118d, and the reflecting elements 102c, 102d, 102g, and 102h supplied with the same potential reflect the incident wave with the same phase. Similarly, the reflecting elements 102c, 102d, 102g, and 102h supplied with the same potential contained in the control signal SS(m / k-1) reflect the incident wave with the same phase, and the four reflecting elements 102 supplied with the same potential contained in the control signal SS(m / k) reflect the incident wave with the same phase.

[0073] In the K+1th FRAME, the IC chip 130 supplies each signal shown in Figure 9 to the corresponding reflective element 102, similar to the Kth FRAME, and the radio wave reflector 100 can reflect the incident wave with a phase (reflection angle) corresponding to the potential supplied in the K+1th FRAME.

[0074] In the comparative example of the radio wave reflector, among the multiple reflecting elements, the multiple reflecting elements provided along the first direction D1 receive different control signals. On the other hand, in the radio wave reflector 100, for example, among the multiple reflecting elements 102, the reflecting elements provided along the first direction D1 are bundled together, so the bundled reflecting elements (patch electrodes) receive the same control signal. In the radio wave reflector 100, the area of ​​the patch electrodes is larger than in the comparative example of the radio wave reflector due to the bundling of the reflecting elements (patch electrodes), but the driving method of the radio wave reflector 100 includes supplying the same control signal to the bundled reflecting elements (patch electrodes). As a result, the time for supplying the control signal to the bundled reflecting elements (patch electrodes) (for example, referred to as the writing time) can be the time obtained by multiplying the time for supplying the control signal to a single reflecting element in the comparative example of the radio wave reflector by the number of bundled reflecting elements. As a result, although the area of ​​the patch electrodes in the radio wave reflector 100 is larger than that of the radio wave reflector in the comparative example due to the bundling of reflective elements (patch electrodes), the driving method of the radio wave reflector 100 can ensure sufficient writing time.

[0075] <1-6. Setting the Phase Difference> Referring to Figures 10 to 12, the method for setting the phase difference of each reflecting element 102 in the radio wave reflecting device 100 will be explained. Figure 10 is a diagram showing the arrangement of patch electrodes 108P and an example of the equivalent phase plane in the radio wave reflecting device 100P according to a comparative example. Figure 11 is a diagram showing the arrangement of patch electrodes 108 and an example of the equivalent phase plane in the radio wave reflecting device 100 according to the first embodiment. Figure 12 is a diagram showing the relationship between element number n and the center position Xn of the reflecting element in the radio wave reflecting device 100P according to a comparative example, and is a diagram showing the relationship between element number n and the center position Dn of the reflecting element in the radio wave reflecting device 100 according to the first embodiment. Descriptions of configurations identical or similar to those in Figures 1 to 9 will be omitted, and configurations identical or similar to those in Figures 1 to 9 may be described as necessary.

[0076] For example, the multiple reflective elements 102P (reflective elements 102Pa to 102Pd) in the radio wave reflector 100P are not bundled together along the first direction D1 as shown in Figure 10, and control signals are supplied independently to each of them. The distance (element pitch) between the center O of one reflective element 102P and the center O of the adjacent reflective element 102P is distance d.

[0077] Furthermore, if element number n and element position Xn are inscribed on each reflective element 102P along the first direction D1, then, as shown in Figure 12, the element positions n of each reflective element 102Pa to 102Pl will be inscribed as 0 to 11 (n=0 to n=11), and the element positions Xn of reflective elements 102Pa to 102Pl will be inscribed as 0 to 11d (X0=0 to X11=11d).

[0078] Furthermore, the phase difference ΔΦ in the radio wave reflector 100P according to the comparative example is expressed by formula (1), using the element number n, the element pitch distance d, the wavelength λ of the reflected wave relative to the incident wave, and the reflection angle θ of the reflected wave relative to the incident wave.

[0079]

[0080] As shown in Figure 10, the equiphase surface 200P in the radio wave reflector 100P according to the comparative example is shown by projecting the centers O of each of the reflecting elements 102Pa to 102Pd (patch electrodes 108Pa to 108Pd) into the third direction D3 and representing the equiphase diagram when the radio waves are reflected at a reflection angle θ.

[0081] On the other hand, if we focus on one row along the first direction D1, for example, the multiple reflective elements 102 (reflective elements 102a to 102d) in the radio wave reflector 100 are bundled together in pairs along the first direction D1, as shown in Figure 11. Referring to the contents explained in "1-1. Overview of the radio wave reflector 100" to "1-5. Driving method of the radio wave reflector 100", if we focus on one row along the first direction D1, the same control signal (control signal SS(1), control signal SS(2)) is supplied to the two reflective elements 102 (102a and 102b, and 102c and 102d) bundled together along the first direction D1. For example, the two bundled reflective elements 102a and 102b are denoted as reflective element group 202a, and the two bundled reflective elements 102c and 102d adjacent to reflective element group 202a are denoted as reflective element group 202b.

[0082] The group of reflective elements 202 in the radio wave reflector 100 corresponds to one reflective element 102P in the radio wave reflector 100P, and the distance D between the center OD of the group of reflective elements 202a and the center OD of the adjacent group of reflective elements 202b in the radio wave reflector 100 corresponds to the element pitch in the radio wave reflector 100P. The distance D is twice the distance d, that is, D = 2d.

[0083] Furthermore, as shown in Figure 12, the element number n along the first direction D1 in the radio wave reflector 100 is indicated as 0 to 11 (n=0 to n=11) for each element position n of the reflecting elements 102a to 102l, similar to the element number n along the first direction D1 in the radio wave reflector 100P. Also, the center position Dn along the first direction D1 in the radio wave reflector 100 corresponds to the center position of the two bundled reflecting elements 102, that is, the center position of one reflecting element group 202, and corresponds to the element position Xn along the first direction D1 in the radio wave reflector 100P. As shown in Figure 12, the center position D0 of the reflecting elements 102a and 102b (i.e., the center position D0 of the reflecting element group 202a) is 0.5d, and the center position D1 of the reflecting elements 102c and 102d (i.e., the center position D1 of the reflecting element group 202b) is 2.5d. From the center position D1 onward, the center positions D2 to D5 are each spaced apart by the element pitch (distance D = 2d). That is, the center position of one group of reflective elements 202 is 1 / 2 (d / 2) of the distance between the centers of the smallest number n(0) and the largest number n(1) among at least two reflective elements 102, and the center position of a group of reflective elements 202b adjacent to a group of reflective elements 202a is the distance d / 2 between the centers plus the distance D (= 2d) (5 / 2d = 2.5d).

[0084] The phase difference ΔΦD in the radio wave reflector 100 is expressed by formula (2), where n is the element number, D is the element pitch, λ is the wavelength of the reflected wave relative to the incident wave, and θ is the reflection angle of the reflected wave relative to the incident wave.

[0085]

[0086] As shown in Figure 11, the equiphase surface 200Da in the radio wave reflector 100 is represented by projecting the center OD of the reflector group 202a and the respective centers O of the reflectors 102a and 102b within the reflector group 202a, and the equiphase surface 200Db is represented by projecting the center OD of the reflector group 202b and the respective centers O of the reflectors 102c and 102d within the reflector group 202b. The surface 200R that includes the respective centers OD of the projected reflector groups 202a and 202b is an ideal equiphase surface. For example, the incident wave is reflected perpendicularly to the surface 200R at the reflection angle θ.

[0087] Since the radio wave reflector 100 can supply the same signal (control signal and scanning signal) to each patch electrode 108 of a plurality of reflective elements 102 bundled together, the number of wires arranged in the peripheral region 122 can be reduced and the frame area can be made smaller compared to the patch electrode 108P of the reflective element 102P in the comparative example. As a result, the frame area relative to the effective area of ​​the radio wave reflector 100 is smaller than that of the patch electrode 108P of the reflective element 102P in the comparative example, so the external dimensions of the radio wave reflector 100 can be made smaller.

[0088] <Second Embodiment> In the first embodiment, the radio wave reflector 100 was described as having a configuration in which a group of reflectors 202, each consisting of four reflectors 102 bundled together, forms a single unit, and as another example, a configuration in which a group of reflectors 202, each consisting of two reflectors 102 bundled together along a first direction D1, forms a single unit. However, the radio wave reflector 100 is not limited to the configuration described in the first embodiment. The radio wave reflector 100 can be implemented in various ways.

[0089] For example, the radio wave reflector 100A according to the second embodiment includes, as an example of a configuration different from the first embodiment, a configuration in which a group of reflecting elements 202, in which three reflecting elements 102 are bundled together along a first direction D1, is used as a single unit. Configurations in the radio wave reflector 100A other than the configuration in which a group of reflecting elements 202, in which three reflecting elements 102 are bundled together along a first direction D1, and configurations other than those related to said configuration, are the same as the configuration of the radio wave reflector 100. Descriptions of configurations identical or similar to those of the radio wave reflector 100 are omitted, and configurations identical or similar to those of the radio wave reflector 100 may be described as necessary.

[0090] Figure 13 shows the relationship between element number n and center position Dn in the radio wave reflector 100A. Figure 14 is a plot diagram showing an example of the relationship between the center position Dn and relative phase of three bundled reflecting elements 102 (reflecting element group 202) in the radio wave reflector 100. Figure 15 is a plot diagram showing the simulation results of the radio wave reflector shown in Figure 14. Descriptions of configurations identical or similar to those in Figures 1 to 12 are omitted, and configurations identical or similar to those in Figures 1 to 12 may be described as necessary.

[0091] In the radio wave reflector 100A, multiple reflecting elements 102 are bundled together in a first direction D1, with three reflecting elements 102 (102a-102c, 102d-102f, 102g-102i, 102j-102l). Each of the bundled three reflecting elements 102 is denoted as a reflecting element group 202 (202a-202d). As described in "1-1. Overview of the Radio Wave Reflector 100" to "1-5. Driving Method of the Radio Wave Reflector 100", the bundled reflecting elements are supplied with the same scanning signal SG and the same control signal SS.

[0092] In the radio wave reflector 100A, the distance D (element pitch) between the centers of adjacent reflector groups 202 is three times the distance d, that is, the distance D (element pitch) in the radio wave reflector 100A is 3d.

[0093] As shown in Figure 13, the element number n along the first direction D1 in the radio wave reflector 100A is indicated as 0 to 11 (n=0 to n=11) for each element position n of the reflecting elements 102a to 102l, similar to the element number n along the first direction D1 in the radio wave reflector 100. Furthermore, the central position Dn along the first direction D1 in the radio wave reflector 100A corresponds to the central position of the three bundled reflecting elements 102, that is, the central position of one group of reflecting elements 202. The central position D0 of the reflecting elements 102a to 102c (i.e., the central position D0 of the reflecting element group 202a) is d, and the central position D1 of the reflecting elements 102d to 102f (i.e., the central position D1 of the reflecting element group 202b) is 4d. From central position D1 onward, central positions D2 and D3 are separated by an element pitch (distance D=3d), respectively.

[0094] Furthermore, as shown in Figure 14, the relative phase (relative phase [deg]) with respect to the center position Dn of the elements in the radio wave reflector 100A is plotted in a stepwise manner at equal intervals [mm] for each of the three bundled reflecting elements. That is, the relative phase is set (determined) so that the phase difference between adjacent groups of reflecting elements is the same phase, and the three bundled reflecting elements are supplied with a potential corresponding to the same phase according to the set (determined) relative phase by the control signal SS. The three bundled reflecting elements 102a to 102c (one group of reflecting elements 202a) are supplied with a potential VA corresponding to the same phase by the control signal SS, and the group of reflecting elements 202b adjacent to group 202a is supplied with a potential VB corresponding to the same phase according to the relative phase by the control signal SS. For example, potential VA is different from potential VB.

[0095] Furthermore, the simulation results of the relative array factor [dB] with respect to the reflection angle θ [deg] in the radio wave reflector 100A are plotted as shown in Figure 15. For example, although a detailed explanation is omitted, the simulation results shown in Figure 15 are the results calculated based on the aforementioned formula. As an example, the parameters of the radio wave reflector 100A in the simulation shown in Figure 15 are: the number of reflecting elements 102 (element number n) is 68 (the group of reflecting elements is 23), the distance d corresponding to the element pitch is 3.7 mm (distance D is 11.1 mm), the frequency of the radio waves is 28 GHz (wavelength λ is 10.71 mm), and the reflection angle θ is 15 deg. At this time, there are 23 first and second signal lines corresponding to the bundled group of reflecting elements.

[0096] For example, the array factor is one indicator of the directivity of an array antenna. Furthermore, the array factor includes, for example, the array factor at the main lobe level when the reflection angle θ is near 0 degrees, and the array factor at the side lobe level around the reflection angle θ (e.g., the grating lobe). Generally, side lobes are a source of interference and increased noise from the surroundings of a radio wave reflector, so an array factor with a low side lobe level is required. Also, since high antenna gain is required, it is important for radio wave reflectors to maintain the gain as much as possible while reducing the side lobe level.

[0097] As shown in Figure 15, the reflection angle θ increases as you move towards the positive side of the figure relative to 0 degrees, and decreases as you move towards the negative side of the figure. The relative array factor is 0 dB at the top of the figure and decreases as you move towards the negative side of the figure. The radio wave reflector 100A has its maximum relative array factor intensity when the reflection angle θ is near 0 degrees, and the grating lobes in the side lobes on the negative side of the reflection angle θ are suppressed to a sufficiently lower intensity than the maximum intensity.

[0098] Therefore, the radio wave reflector 100A can supply the same signal from the same signal line by treating the three bundled reflecting elements as a single group of reflecting elements. This reduces the number of wires arranged in the peripheral region 122 and increases the area of ​​the patch electrodes, thereby providing an antenna factor that satisfies the characteristics of a radio wave reflector.

[0099] <Third Embodiment> For example, the radio wave reflector 100B according to the third embodiment includes, as an example of a different form from the first embodiment, a configuration of reflective elements with unequal spacing, which combines a group of three radio wave reflecting elements bundled together along a first direction D1 with a group of two radio wave reflecting elements bundled together. Configurations in the radio wave reflector 100B other than the configuration of reflective elements with unequal spacing, and configurations other than those related to said configuration, are the same as the configuration of the radio wave reflector 100. Descriptions of configurations identical or similar to those of the radio wave reflector 100 are omitted, and configurations identical or similar to those of the radio wave reflector 100 may be described as necessary.

[0100] Figure 16 shows the relationship between element number n and center position Dn in the radio wave reflector 100B. Figure 17 is a plot showing an example of the relationship between the center position Dn and relative phase of a group of unequal-pitch reflecting elements in the radio wave reflector 100B. Figure 18 is a plot showing the simulation results of the radio wave reflector shown in Figure 17. Descriptions of configurations identical or similar to those in Figures 1 to 15 are omitted, and configurations identical or similar to those in Figures 1 to 15 may be described as necessary.

[0101] The multiple reflective elements 102 (multiple reflective element groups 202) in the radio wave reflector 100B include a region where the reflective elements are densely arranged and a region where the reflective elements are sparsely arranged, extending outward from the center of the multiple reflective elements 102 along a first direction D1. For example, the region where the reflective elements are densely arranged includes a reflective element group 202 (202b, 202c, 202d) in which two reflective elements 102 (102d and 102e, 102f and 102g, 102h and 102i) are bundled together, and the region where the reflective elements are sparsely arranged includes a reflective element group 202 (202a, 202e) in which three reflective elements 102 (102a to 102c, 102j to 102l) are bundled together. In other words, the radio wave reflector 100B includes a group of reflector elements 202 (202b, 202c, 202d) in which multiple pairs of reflector elements 102 (102d and 102e, 102f and 102g, 102h and 102i) are bundled together, and a group of reflector elements 202 (202a, 202e) in which multiple pairs of reflector elements 102 (102a to 102c, 102j to 102l) are bundled together. As described in "1-1. Overview of the Radio Wave Reflector 100" to "1-5. Driving Method of the Radio Wave Reflector 100", the bundled reflector elements are supplied with the same scanning signal SG and the same control signal SS.

[0102] In the radio wave reflector 100B, the distance D between the centers of the reflector element groups 202a and 202e, which are bundles of three reflector elements 102, is three times the distance d (3d), and the distance D between the centers of the reflector element groups 202b to 202d, which are bundles of two reflector elements 102, is twice the distance d (2d).

[0103] As shown in Figure 16, the element number n along the first direction D1 in the radio wave reflector 100B is indicated as 0 to 11 (n=0 to n=11) for each element position n of the reflecting elements 102a to 102l, similar to the element number n along the first direction D1 in the radio wave reflector 100. Furthermore, the central position Dn along the first direction D1 in the radio wave reflector 100B is a combination of three bundled reflecting elements and two bundled reflecting elements. For three bundled reflecting elements 102a to 102c or 102j to 102l, it corresponds to the central position of one reflecting element group 202a or 202e, and the central position D0 of the reflecting elements 102a to 102c (i.e., the central position D0 of the reflecting element group 202a) is d, and the central position D4 of the reflecting elements 102j to 102l (i.e., the central position D4 of the reflecting element group 202b) is 10d. For two bundled reflective elements 102d and 102e, 102f and 102g, or 102h and 102i, the central position D1 corresponds to that of a single reflective element group 202b, 202c, or 202d. The central position D1 of reflective elements 102d and 102e (i.e., the central position D1 of reflective element group 202b) is 3.5d, the central position D2 of reflective elements 102f and 102g (i.e., the central position D2 of reflective element group 202c) is 5.5d, and the central position D3 of reflective elements 102h and 102i (i.e., the central position D3 of reflective element group 202d) is 7.5d.

[0104] Furthermore, for example, the radio wave reflector 100B may include a configuration in which bundled reflective elements are combined, such as two bundled reflective elements, three bundled reflective elements, four bundled reflective elements, and five bundled reflective elements, starting from the center of a plurality of reflective elements 102 and moving outwards. That is, the radio wave reflector 100B may be configured such that the number of bundled reflective elements increases as the region moves from a region where reflective elements are densely arranged to a region where reflective elements are sparsely arranged. For example, the radio wave reflector 100B includes a group of reflective elements 202 (202b, 202c, 202d) in which two reflective elements 102 (102d and 102e, 102f and 102g, 102h and 102i) are bundled, and the region where reflective elements are sparsely arranged includes a group of reflective elements 202 (202a, 202e) in which three reflective elements 102 (102a to 102c, 102j to 102l) are bundled. In other words, the radio wave reflector 100B includes a group of reflectors 202 (202b, 202c, 202d) in which a plurality of two reflectors 102 (102d and 102e, 102f and 102g, 102h and 102i) are bundled together, and a group of reflectors 202 (202a, 202e) in which a plurality of three reflectors 102 (102a to 102c, 102j to 102l) are bundled together.

[0105] For example, as shown in Figure 17, the relative phase (relative phase [deg]) of the elements in the radio wave reflector 100B with respect to the center position Dn is plotted in a stepped pattern at unequal intervals [mm] by combinations of bundled five reflectors, bundled four reflectors, bundled three reflectors, and bundled two reflectors. That is, each of the bundled five reflectors, the bundled four reflectors adjacent to the bundled five reflectors, the bundled three reflectors adjacent to the bundled four reflectors, and the bundled two reflectors adjacent to the bundled three reflectors are supplied with a potential corresponding to the same phase by the control signal SS.

[0106] Furthermore, the simulation results of the relative array factor [dB] with respect to the reflection angle θ [deg] in the radio wave reflector 100B are plotted as shown in Figure 18. In the simulation for the radio wave reflector 100B, there are 24 reflecting elements, and the configuration of the simulation other than having 24 reflecting elements is the same as the configuration described in the "Second Embodiment". In this case, there are 24 first signal lines and second signal lines corresponding to the bundled reflecting elements.

[0107] As shown in Figure 18, the radio wave reflector 100B achieves its maximum intensity in relative array factor when the reflection angle θ is near 0 degrees, similar to the radio wave reflector 100A. The grating lobe in the side lobe on the negative side of the reflection angle θ is significantly lower than the maximum intensity and is reduced compared to the relative array factor in the grating lobe of the radio wave reflector 100A.

[0108] Therefore, the radio wave reflector 100B includes multiple reflecting elements (multiple groups of reflecting elements) with unequal pitch intervals, and by bundling multiple radio wave reflecting elements, it is possible to supply the same signal from the same signal line. This reduces the number of wires arranged in the peripheral region 122 and increases the area of ​​the patch electrodes, thereby providing an antenna factor that satisfies the characteristics of a radio wave reflector.

[0109] The various configurations of the radio wave reflector and radio wave reflecting device illustrated as one embodiment of the present invention can be combined as appropriate, as long as they do not contradict each other. Furthermore, any radio wave reflector and radio wave reflecting device disclosed in this specification and drawings, to which a person skilled in the art has added, deleted, or modified components, or to which processes have been added, omitted, or conditions changed, are also included in the scope of the present invention, as long as they retain the essence of the present invention.

[0110] Any effects or benefits other than those brought about by the embodiments disclosed herein are to be understood to be brought about by the present invention if they are clear from the description herein or can be easily predicted by a person skilled in the art.

[0111] 100...Radio wave reflector, 100A...Radio wave reflector, 100B...Radio wave reflector, 100P...Radio wave reflector, 102...Reflective element, 102a...Reflective element, 102b...Reflective element, 102c...Reflective element, 102d...Reflective element, 102e...Reflective element, 102f...Reflective element, 102g...Reflective element, 102h...Reflective element, 102i...Reflective element, 102j...Reflective element, 102k...Reflective element, 102l...Reflective element, 102P...Reflective element, 102Pa...Reflective element, 102Pb...Reflective element, 102Pc...Reflective element, 102Pd...Reflective element, 102Pe...Reflective element, 102Pf...Reflective element Reflecting element, 102Pg...Reflecting element, 102Ph...Reflecting element, 102Pi...Reflecting element, 102Pj...Reflecting element, 102Pk...Reflecting element, 102Pl...Reflecting element, 103...Circuit, 104...Dielectric substrate, 104a...First surface, 106...Opping substrate, 106a...First surface, 108...Patch electrode, 108a...Patch electrode, 108b...Patch electrode, 108c...Patch electrode, 108d...Patch electrode, 108e...Patch electrode, 108f...Patch electrode, 108g...Patch electrode, 108h...Patch electrode, 108P...Patch electrode, 108Pa...Patch electrode, 108Pb...Patch electrode, 10 8Pc...Patch electrode, 108Pd...Patch electrode, 110...Conductive layer, 110a...Conductive layer, 112a...Alignment layer, 112b...Alignment layer, 113...Common wiring, 114...Liquid crystal layer, 115...Connection part, 116...Liquid crystal molecule, 118...First signal line, 118a...First signal line, 118b...First signal line, 118c...First signal line, 118d...First signal line, 119...First connection signal line, 119a...First connection signal line, 119b...First connection signal line, 120...Reflector, 122...Peripheral area, 126...Terminal part, 128...Sealing material, 130...IC chip, 130a...First drive circuit, 130b...Second drive Circuit, 132...Second signal line, 132a...Second signal line, 132b...Second signal line, 132c...Second signal line, 132d...Second signal line, 133...Second connection signal line, 133a...Second connection signal line, 133b...Second connection signal line, 134...Switching element, 136...Switching element, 142a...Semiconductor layer, 160...Transistor, 161...Gate electrode, 163...Source electrode, 163a...Contact hole, 164...Drain electrode, 164a...Contact hole, 180...Array layer, 200Da...Equiphase plane, 200Db...Equiphase plane, 200P...Equiphase plane, 200R...Plane,202... Reflecting element group, 202a... Reflecting element group, 202b... Reflecting element group, 202c... Reflecting element group, 202d... Reflecting element group, 202e... Reflecting element group,

Claims

1. A radio wave reflector comprising: a plurality of reflective elements arranged in a first direction and a second direction intersecting the first direction; a first signal line extending in the first direction and supplying a control signal including a potential corresponding to the phase of the reflected radio wave; and a second signal line extending in the second direction and supplying a scanning signal, wherein each of the plurality of reflective elements comprises: a patch electrode; a conductive layer disposed at a distance from the patch electrode and facing the patch electrode; a liquid crystal layer disposed between the patch electrode and the conductive layer; and a switching element connected to the first signal line and the second signal line and electrically connecting the patch electrode and the first signal line based on the control signal, wherein at least two adjacent reflective elements along the first direction are connected to the same first signal line and the same second signal line.

2. The radio wave reflector according to claim 1, comprising a plurality of groups of reflective elements, wherein one of the plurality of groups of reflective elements comprises at least two reflective elements, and when the number n of the plurality of reflective elements arranged along the first direction and the pitch of the plurality of reflective elements is distance d, and the pitch of the plurality of groups of reflective elements is distance D, then distance D is an integer multiple of distance d, the center position of the one group of reflective elements is half the distance between the centers of the smallest number n and the largest number n among the at least two reflective elements, and the center position of a group of reflective elements adjacent to the one group of reflective elements is half the distance between the centers plus distance D.

3. The phase difference ΔΦD in the radio wave reflector is calculated using the number n of the plurality of reflecting elements arranged along the first direction, the distance D as the pitch between the plurality of reflecting elements, the wavelength λ of the reflected radio wave, and the reflection angle θ of the reflected wave. A radio wave reflector according to claim 1, represented by formula (2).

4. The radio wave reflector according to claim 1, wherein the first signal line is one of the two signal lines branched from the first connection signal line and the first connection signal line.

5. The radio wave reflector according to claim 1, wherein the second signal line is one of the two signal lines branched from the second connecting signal line and the second connecting signal line.

6. The radio wave reflector according to claim 1, wherein the size of each patch electrode of the plurality of reflecting elements is the same.

7. The radio wave reflector according to claim 1, wherein the plurality of reflecting elements are capable of reflecting radio waves in the frequency band of 24 GHz to 29 GHz.

8. A radio wave reflector comprising: a radio wave reflector according to any one of claims 1 to 7; and a control circuit electrically connected to the first signal line and the second signal line, which supplies a control signal to the first signal line that includes a potential corresponding to the phase of the reflected radio wave, and supplies the scanning signal to the second signal line.

9. A method for driving a radio wave reflector, comprising: a radio wave reflector according to any one of claims 1 to 7; and a control circuit electrically connected to the first signal line and the second signal line, which supplies a control signal to the first signal line including a potential corresponding to the phase of the reflected radio wave and supplies the scanning signal to the second signal line, wherein the driving method includes supplying the control signal to the first signal line connected to at least two of the plurality of reflecting elements, supplying the scanning signal to the second signal line connected to the two reflecting elements, and reflecting the reflected radio wave at a predetermined reflection angle.

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