radio wave reflector

Abstract

Provided is a radio wave reflecting plate that has excellent light transmissivity.　This radio wave reflecting plate comprises: a plurality of separate regions that are arranged in a matrix, and each have a first region and one or more second regions other than the first region; a connection region that is located in the gaps between the plurality of separate regions, has a lattice shape, and is connected to the plurality of separate regions; a first substrate that has a plurality of patch electrodes, each patch electrode being located in the first region of a single corresponding separate region among the plurality of separate regions; a second substrate that has a common electrode, said common electrode facing the plurality of patch electrodes and being located in the connection region and the respective first regions of the separate regions; and a liquid crystal layer that is retained between the first substrate and the second substrate and faces the plurality of patch electrodes.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to radio wave reflectors. [Background technology]

[0002] Research is underway on radio wave reflectors that can control the direction of radio wave reflection using liquid crystals. In these radio wave reflectors, reflection control units having reflective electrodes are arranged in one (or two) dimensions. In the radio wave reflector, it is necessary to adjust the dielectric constant of the liquid crystal so that the phase difference of the reflected radio waves is constant between adjacent reflection control units. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-103201 [Patent Document 2] Special Publication No. 2019-530387 [Overview of the project] [Problems that the invention aims to solve]

[0004] This embodiment provides a radio wave reflector with excellent light transmittance. [Means for solving the problem]

[0005] A radio wave reflector according to one embodiment is A plurality of individual regions arranged in a matrix along mutually orthogonal X and Y axes, each of which comprises a first region and one or more second regions other than the first region, A connecting region located in the gap between the plurality of individual regions, having a grid-like shape and connected to the plurality of individual regions, A first substrate having multiple patch electrodes, wherein each patch electrode is located in a first region of a corresponding individual region among the multiple individual regions, A second substrate having a common electrode, wherein the common electrode is located in the first region and the connection region of each of the individual regions and faces the plurality of patch electrodes in a direction parallel to the Z axis which is perpendicular to the X axis and the Y axis, respectively, the second substrate, The system comprises a liquid crystal layer held between the first substrate and the second substrate, and facing the plurality of patch electrodes. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a cross-sectional view showing a radio wave reflector according to the first embodiment. [Figure 2] Figure 2 is a plan view showing a radio wave reflector according to Example 1 of the first embodiment described above. [Figure 3] Figure 3 is an enlarged plan view showing a part of the radio wave reflector according to Embodiment 1 described above, and is a diagram showing multiple individual regions, connection regions, and surrounding regions. [Figure 4] Figure 4 is an enlarged plan view showing multiple patch electrodes and multiple connecting wires according to the above embodiment 1. [Figure 5] Figure 5 is an enlarged plan view showing a part of the common electrode according to the above embodiment 1. [Figure 6] Figure 6 is an enlarged cross-sectional view showing a part of the radio wave reflector according to Embodiment 1 described above, and shows a single reflection control unit. [Figure 7] Figure 7 is an enlarged cross-sectional view showing a part of the radio wave reflector according to Embodiment 1 described above, and shows a plurality of reflection control units. [Figure 8] Figure 8 is a timing chart showing the change in voltage applied to the patch electrode over time in the driving method for the radio wave reflector according to Embodiment 1 described above. [Figure 9] Figure 9 is an enlarged plan view showing a part of the radio wave reflector according to Embodiment 2 of the first embodiment described above, and is a diagram showing multiple individual regions, connection regions, and surrounding regions. [Figure 10] Figure 10 is an enlarged plan view showing multiple patch electrodes and multiple connection wires according to the above embodiment 2. [Figure 11]FIG. 11 is an enlarged plan view showing a part of the common electrode according to the second embodiment. [Figure 12] FIG. 12 is an enlarged plan view showing a part of the radio wave reflector according to the fifth embodiment of the first embodiment, and is a view showing a plurality of individual regions, connection regions, and peripheral regions. [Figure 13] FIG. 13 is an enlarged plan view showing a plurality of patch electrodes and a plurality of connection wirings according to the fifth embodiment. [Figure 14] FIG. 14 is an enlarged plan view showing a part of the common electrode according to the fifth embodiment. [Figure 15] FIG. 15 is an enlarged plan view showing a part of the radio wave reflector according to the modified example of the first embodiment, and is a view showing a plurality of individual regions, connection regions, and peripheral regions. [Figure 16] FIG. 16 is an enlarged plan view showing a plurality of patch electrodes and a plurality of connection wirings according to the modified example. [Figure 17] FIG. 17 is an enlarged plan view showing a part of the common electrode according to the modified example. [Figure 18] FIG. 18 is a plan view showing a radio wave reflector according to the second embodiment. [Figure 19] FIG. 19 is an enlarged cross-sectional view showing a part of the radio wave reflector according to the second embodiment. [Figure 20] FIG. 20 is an enlarged plan view showing a plurality of patch electrodes according to the second embodiment, and is a view for explaining an example of a voltage applied to the plurality of patch electrodes in a driving method of the radio wave reflector. [Figure 21] FIG. 30 is an enlarged plan view showing a plurality of patch electrodes according to the second embodiment, and is a view for explaining another example of a voltage applied to the plurality of patch electrodes in a driving method of the radio wave reflector. [Figure 22] FIG. 22 is an enlarged plan view showing a plurality of patch electrodes of the radio wave reflector according to the modified example of the second embodiment. [Figure 23] FIG. 23 is an enlarged plan view showing a part of the common electrode of the radio wave reflector according to the modified example of the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0007] The embodiments of the present invention will be described below with reference to the drawings. Note that the disclosure is merely an example, and modifications that can be easily conceived by those skilled in the art while maintaining the spirit of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, 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 in each drawing, elements similar to those described above in previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0008] (First embodiment) First, a first embodiment will be described. Figure 1 is a cross-sectional view showing a radio wave reflector RE according to this first embodiment. The radio wave reflector RE can reflect radio waves and functions as a relay device for radio waves.

[0009] As shown in Figure 1, the radio wave reflector RE comprises a first substrate SUB1, a second substrate SUB2, and a liquid crystal layer LC. The first substrate SUB1 has an electrically insulating base material 1, a plurality of patch electrodes PE, and an alignment film AL1. The base material 1 is formed in a flat plate shape and extends along the XY plane, which includes mutually orthogonal X and Y axes. The alignment film AL1 covers the plurality of patch electrodes PE.

[0010] The second substrate SUB2 is positioned opposite the first substrate SUB1 with a predetermined gap between them. The second substrate SUB2 has an electrically insulating base material 2, a common electrode CE, and an alignment film AL2. The base material 2 is formed in a flat plate shape and extends along the XY plane. The common electrode CE faces a plurality of patch electrodes PE in a direction parallel to the Z axis, which is perpendicular to the X and Y axes, respectively. The alignment film AL2 covers the common electrode CE. In this embodiment, the alignment film AL1 and the alignment film AL2 are each horizontal alignment films.

[0011] The first substrate SUB1 and the second substrate SUB2 are joined together by a sealing material SE placed at their respective peripheries. The liquid crystal layer LC is provided in the space enclosed by the first substrate SUB1, the second substrate SUB2, and the sealing material SE. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2. The liquid crystal layer LC faces multiple patch electrodes PE on one side and a common electrode CE on the other.

[0012] Here, the thickness of the liquid crystal layer (LC) (cell gap) is d. l Let's assume the thickness is d. l This is greater than the thickness of the liquid crystal layer in a typical liquid crystal display panel. In this embodiment, the thickness d l It is 50 μm. However, if the reflection phase of the radio waves can be sufficiently adjusted, the thickness d l The thickness may be less than 50 μm. Alternatively, to increase the reflection angle of radio waves, the thickness d l The thickness may exceed 50 μm. The liquid crystal material used in the liquid crystal layer LC of the radio wave reflector RE is different from the liquid crystal material used in ordinary liquid crystal display panels.

[0013] A common voltage is applied to the common electrode CE, and the potential of the common electrode CE is fixed. In this embodiment, the common voltage is 0V. A voltage is also applied to the patch electrode PE. In this embodiment, the patch electrode PE is AC driven. The liquid crystal layer LC is driven by a so-called longitudinal electric field. The voltage applied between the patch electrode PE and the common electrode CE acts on the liquid crystal layer LC, causing the dielectric constant of the liquid crystal layer LC to change.

[0014] When the dielectric constant of the liquid crystal layer (LC) changes, the propagation speed of radio waves in the LC also changes. Therefore, by adjusting the voltage applied to the LC, the reflection phase of radio waves can be adjusted. Consequently, the direction of reflection of radio waves can be adjusted. In this embodiment, the absolute value of the voltage applied to the LC is 10V or less. This is because the dielectric constant of the LC saturates at 10V. However, depending on the dielectric constant of the LC, the voltage at which it saturates will differ, so the absolute value of the voltage applied to the LC may exceed 10V. For example, if an improvement in the response speed of the liquid crystal is required, a voltage exceeding 10V may be applied to the LC, followed by a voltage of 10V or less. The first substrate SUB1 has an incident surface Sa on the side opposite to the side facing the second substrate SUB2. In the figure, the incident wave w1 is the radio wave incident on the radio wave reflector RE, and the reflected wave w2 is the radio wave reflected by the radio wave reflector RE. In this first embodiment, the frequency band of the incident wave w1 is assumed to be 28 GHz.

[0015] Next, several embodiments of the first embodiment will be described. (Example 1 of the first embodiment) First, let's describe Example 1 of the first embodiment. Figure 2 is a plan view showing the radio wave reflector RE according to this Example 1. As shown in Figure 2, multiple patch electrodes PE are arranged in a matrix with spacing along the X and Y axes, respectively. In the XY plane, the multiple patch electrodes PE have the same shape and size.

[0016] Multiple patch electrodes PE are arranged at equal intervals along the X-axis and also at equal intervals along the Y-axis. Multiple patch electrodes PE are included in multiple patch electrode groups GP that extend along the Y-axis and are arranged along the X-axis. Multiple patch electrode groups GP include the first patch electrode group GP1 to the eighth patch electrode group GP8.

[0017] The first patch electrode group GP1 has multiple first patch electrodes PE1, the second patch electrode group GP2 has multiple second patch electrodes PE2, the third patch electrode group GP3 has multiple third patch electrodes PE3, the fourth patch electrode group GP4 has multiple fourth patch electrodes PE4, the fifth patch electrode group GP5 has multiple fifth patch electrodes PE5, the sixth patch electrode group GP6 has multiple sixth patch electrodes PE6, the seventh patch electrode group GP7 has multiple seventh patch electrodes PE7, and the eighth patch electrode group GP8 has multiple eighth patch electrodes PE8. For example, the second patch electrode PE2 is located between the first patch electrode PE1 and the third patch electrode PE3 in the direction along the X axis.

[0018] Each patch electrode group GP includes multiple patch electrodes PE arranged along the Y-axis and electrically connected to one another. In this embodiment 1, the multiple patch electrodes PE of each patch electrode group GP are electrically connected by connecting wires L. The first substrate SUB1 extends along the Y-axis and has multiple connecting wires L arranged along the X-axis. The connecting wires L extend to the region of the substrate 1 that does not face the second substrate SUB2. Unlike this embodiment 1, the multiple connecting wires L may be connected one-to-one with the multiple patch electrodes PE.

[0019] In this embodiment 1, the multiple patch electrodes PE arranged along the Y-axis and the connecting wiring L are integrally formed from the same conductor. However, the multiple patch electrodes PE and the connecting wiring L may be formed from different conductors. The patch electrodes PE, the connecting wiring L, and the common electrode CE are formed from a metal or a conductor equivalent to metal. The connecting wiring L may be connected to the pads of an outer lead bonding (OLB) (not shown).

[0020] The connecting wire L is a thin wire, and its width is sufficiently small compared to the length Px1 described later. The width of the connecting wire L is several μm, on the order of μm. In this embodiment 1, the width of the connecting wire L is 5 μm. The connecting wire L needs to have sufficient conductivity to transmit the control signal (voltage) applied to the patch electrode PE, but if the width of the connecting wire L is too wide, it will lead to a decrease in the reflectivity of the reflected wave w2. It is desirable for the width of the connecting wire L to be as small as possible. When the connecting wire L is formed using photolithography, it is desirable to make the width of the connecting wire L as small as possible, for example, 1 to 2 μm. Also, if the width of the connecting wire L is too large, it will change the sensitivity of the frequency components of the radio waves, which is undesirable. The sealing material SE is placed at the periphery (square-frame-shaped peripheral region PA) of the area where the first substrate SUB1 and the second substrate SUB2 face each other.

[0021] Figure 2 shows an example in which eight patch electrodes PE are arranged along the X-axis and eight along the Y-axis. However, the number of patch electrodes PE can be varied. For example, 100 patch electrodes PE may be arranged along the X-axis, and multiple patches (e.g., 100) may be arranged along the Y-axis. The length of the radio wave reflector RE (first substrate SUB1) along the X-axis is, for example, 40 to 80 cm.

[0022] Figure 3 is an enlarged plan view showing a part of the radio wave reflector RE according to the above embodiment 1, and shows multiple individual regions IA, a connection region CA, and a surrounding region PA. As shown in Figure 3, the region where the first substrate SUB1 and the second substrate SUB2 face each other comprises multiple individual regions IA, a connection region CA, and a peripheral region PA. The multiple individual regions IA and the connection region CA are regions surrounded by the peripheral region PA.

[0023] Multiple individual regions IA are arranged in a matrix along the X and Y axes, respectively. Each individual region IA has a first region A1 and one or more second regions A2 other than the first region A1. Connecting regions CA are located in the gaps between the multiple individual regions IA, have a grid-like shape, and are connected to the multiple individual regions IA.

[0024] More specifically, the first region A1 is a frame-shaped region with a square outer perimeter and a square inner perimeter. In the first region A1, the centroid of the outer perimeter and the centroid of the inner perimeter are the same in a plan view. Each individual region IA has a second region A2. The second region A2 is the region enclosed by the first region A1 and has a square shape.

[0025] Each individual region IA has a length Px1 along the X-axis and a length Py1 along the Y-axis. Within the connected region CA, the area between a pair of adjacent individual regions IA along the X-axis has a length Px2 along the X-axis. Within the connected region CA, the area between a pair of adjacent individual regions IA along the Y-axis has a length Py2 along the Y-axis.

[0026] The first region A1 has lengths Pxa along the X-axis and Pya along the Y-axis. Length Pxa corresponds to the distance between the opposing outer and inner edges of each region in the first region A1 that extends adjacently to the second region A2 along the Y-axis and adjacently to the second region A2 along the X-axis. Length Pya corresponds to the distance between the opposing outer and inner edges of each region in the first region A1 that extends adjacently to the second region A2 along the X-axis and adjacently to the second region A2 along the X-axis. The second region A2 has lengths Pxb along the X-axis and Pyb along the Y-axis.

[0027] In this embodiment 1, lengths Pxa and Pya are each 250 μm (Pxa = Pya = 250 μm), and lengths Pxb and Pyb are each 1000 μm (Pxb = Pyb = 1000 μm). From the above, lengths Px1 and Py1 are each 1.50 mm (Px1 = Py1 = 1.50 mm).

[0028] Furthermore, lengths Px2 and Py2 are each 50 μm (Px2 = Py2 = 50 μm). Multiple individual regions IA are arranged in a first pitch along the X-axis and in a second pitch along the Y-axis. In this embodiment 1, the first pitch and the second pitch are each 1.55 mm.

[0029] Figure 4 is an enlarged plan view showing multiple patch electrodes PE and multiple connecting wires L according to this embodiment 1. As shown in Figure 4, each patch electrode PE has a frame-like shape and is located in the first region A1 of a corresponding individual region IA among a plurality of individual regions IA. In this embodiment 1, each patch electrode PE is located throughout the first region A1 of a corresponding individual region IA and not in the second region A2. The patch electrode PE has a first opening OP1 in the second region A2. In the region inside the peripheral region PA, the connecting wiring L is located in the connecting region CA.

[0030] The shape of each patch electrode PE is 90° rotationally symmetric in a plan view. The contour of the patch electrode PE is square. Note that the contour of the patch electrode PE (individual region IA) is not limited to the square shape of this embodiment 1, but a square, circle, or other shape is desirable. Focusing on the outer shape of the patch electrode PE, a shape with a vertical-to-horizontal aspect ratio of 1:1 is desirable. This is because a 90° rotationally symmetric structure is desirable to accommodate transverse and longitudinal polarization.

[0031] Figure 5 is an enlarged plan view showing a part of the common electrode CE according to this embodiment 1. As shown in Figure 5, the common electrode CE is located in multiple individual regions IA, a connection region CA, and a peripheral region PA, and is continuously provided in multiple individual regions IA, a connection region CA, and a peripheral region PA. In this embodiment 1, the common electrode CE is located in the entire connection region CA. The portion of the common electrode CE located in each individual region IA has a frame-like shape and is located in the entire first region A1 but not in the second region A2. The portion of the common electrode CE located in each individual region IA has a second opening OP2 in the second region A2.

[0032] The shape of the portion of the common electrode CE located in each individual region IA is 90° rotationally symmetrical in a plan view. In this embodiment 1, the contour of the portion of the common electrode CE located in each individual region IA is square. However, the contour of the portion of the common electrode CE located in each individual region IA is not limited to the square shape in this embodiment 1. For example, if the contour of the patch electrode PE (individual region IA) is a perfect circle, then the contour of the portion of the common electrode CE located in each individual region IA may also be a perfect circle. Furthermore, regarding the shape of the portion of the common electrode CE located within each individual region IA, a shape with a vertical-to-horizontal aspect ratio of 1:1 is desirable.

[0033] As shown in Figures 3 to 5, as described above, it is desirable that the shapes of the portions of each patch electrode PE and common electrode CE located in each individual region IA be 90° rotationally symmetrical in a plan view. It is desirable that the shapes of the portions of the common electrode CE located in each individual region IA be identical to the shapes of the respective patch electrodes PE. It is desirable that the portions of the common electrode CE located in each individual region IA overlap with the corresponding patch electrode PE among the multiple patch electrodes PE in a plan view.

[0034] In this embodiment 1, the patch electrode PE, connecting wiring L, and common electrode CE are each made of a metal, for example, TAT, and have light-shielding properties. The above-mentioned TAT has a three-layer laminated structure (Ti-based / Al-based / Ti-based), and has a lower layer made of a metal material mainly composed of Ti, such as Ti (titanium) or alloys containing Ti, an intermediate layer made of a metal material mainly composed of Al, such as Al (aluminum) or alloys containing Al, and an upper layer made of a metal material mainly composed of Ti, such as Ti or alloys containing Ti. Inside the peripheral region PA, the regions in which multiple patch electrodes PE and common electrode CE allow light (visible light) to pass through are multiple second regions A2, or in other words, multiple first light-transmitting regions where the first aperture OP1 of the patch electrode PE and the second aperture OP2 of the common electrode CE overlap. In each individual region IA of this embodiment 1, the aperture ratio is substantially 44%.

[0035] Multiple portions of the common electrode CE located in multiple individual regions IA only need to be electrically connected to each other. Therefore, the common electrode CE does not need to be located throughout the entire connection region CA, and the connection region CA may have multiple third apertures. In that case, within the peripheral region PA, the regions in which the multiple patch electrodes PE and the common electrode CE allow light transmission are the multiple first light transmission regions and the multiple second light transmission regions overlapping the multiple third apertures.

[0036] Figure 6 is an enlarged cross-sectional view showing a part of the radio wave reflector RE according to this embodiment 1, and shows a single reflection control unit RH. In Figure 6, the base material 1 and other components are omitted from the illustration. As shown in Figure 6, the thickness d of the liquid crystal layer LC l The (cell gap) is held by multiple spacers SS. In this embodiment 1, the spacers SS are columnar spacers formed on the second substrate SUB2 and protruding toward the first substrate SUB1.

[0037] The cross-sectional diameter of the spacer SS in the direction parallel to the X-axis is 10 to 20 μm. While the length of the patch electrode PE in the direction parallel to the X-axis and the length of the patch electrode PE in the direction parallel to the Y-axis are on the order of millimeters, the cross-sectional diameter of the spacer SS in the X-direction is on the order of micrometers. Therefore, it is necessary to have multiple spacer SS regardless of whether they are in a region facing the patch electrode PE or not. Also, the proportion of the individual region IA in which multiple spacer SS exist is about 1%.

[0038] Therefore, even if a spacer SS is present in the first region A1, the influence of the spacer SS on the reflected wave w2 is minimal. The spacer SS may be formed on the first substrate SUB1 and protrude towards the second substrate SUB2. Alternatively, the spacer SS may be a spherical spacer.

[0039] The radio wave reflector RE comprises multiple reflection control units RH. Each reflection control unit RH includes one patch electrode PE from among multiple patch electrodes PE, a portion of the common electrode CE facing the patch electrode PE, and a region of the liquid crystal layer LC located in the individual region IA. In each reflection control unit RH, the liquid crystal layer LC is present in at least the entirety of the first region A1.

[0040] When no voltage is applied between the patch electrode PE and the common electrode CE, the dielectric constant in the first region A1 of the liquid crystal layer LC and the dielectric constant in the second region A2 of the liquid crystal layer LC are the same. When a voltage is applied between the patch electrode PE and the common electrode CE, the dielectric constant in the second region A2 of the liquid crystal layer LC does not change substantially, but the dielectric constant in the first region A1 of the liquid crystal layer LC changes. The dielectric constant in the first region A1 of the liquid crystal layer LC is proportional to the voltage applied between the patch electrode PE and the common electrode CE. Therefore, when a voltage is applied between the patch electrode PE and the common electrode CE, the dielectric constant in the first region A1 of the liquid crystal layer LC and the dielectric constant in the second region A2 of the liquid crystal layer LC are different from each other.

[0041] FIG. 7 is an enlarged cross-sectional view showing a part of the radio wave reflector RE according to the first embodiment, and is a view showing a plurality of reflection control units RH. In FIG. 7, illustration of spacers SS and the like is omitted. As shown in FIG. 7, each reflection control unit RH functions to adjust the phase of a radio wave (incident wave w1) incident from the incident surface Sa side according to the voltage applied to the patch electrode PE, and reflect the radio wave to the incident surface Sa side to obtain a reflected wave w2. In each reflection control unit RH, the reflected wave w2 is a combined wave of the radio wave reflected by the patch electrode PE and the radio wave reflected by the common electrode CE.

[0042] In the direction along the X-axis, the patch electrodes PE are arranged at equal intervals. Let the length between adjacent patch electrodes PE be d k . The length d k corresponds to the distance from the geometric center of one patch electrode PE to the geometric center of the adjacent patch electrode PE. In the first embodiment, the reflected wave w2 will be described as having the same phase in the first reflection direction d1. In the X-Z plane of FIG. 7, the first reflection direction d1 is a direction that forms a first angle θ1 with the Z-axis. The first reflection direction d1 is parallel to the X-Z plane.

[0043] For the radio waves reflected by the plurality of reflection control units RH to have the same phase in the first reflection direction d1, it is only necessary that the phases of the radio waves are the same on the straight two-dot chain line. For example, it is only necessary that the phase of the reflected wave w2 at point Q1b and the phase of the reflected wave w2 at point Q2a are the same. The physical straight-line distance from point Q1a to point Q1b of the first patch electrode PE1 is d k × sin θ1. Therefore, when paying attention to the first reflection control unit RH1 and the second reflection control unit RH2, the phase of the reflected wave w2 from the second reflection control unit RH2 may be delayed by a phase amount δ1 from the phase of the reflected wave w2 from the first reflection control unit RH1. Here, the phase amount δ1 is represented by the following formula. δ1 = d k × sin θ1 × 2π / λ

[0044] Next, the driving method for the radio wave reflector RE will be described. Figure 8 is a timing chart showing the change in voltage applied to the patch electrode PE for each period in the driving method for the radio wave reflector RE according to this embodiment 1. In Figure 8, the first period Pd1 to the fifth period Pd5 of the driving period of the radio wave reflector RE are shown.

[0045] As shown in Figures 7 and 8, when the operation of the radio wave reflector RE is started, during the first period Pd1, voltages V are applied to multiple patch electrodes PE so that the radio waves reflected by the multiple reflection control units RH are in phase in the first reflection direction d1. For example, a first voltage V1 is applied to the first patch electrode PE1, a second voltage V2 is applied to the second patch electrode PE2, a third voltage V3 is applied to the third patch electrode PE3, and a fourth voltage V4 is applied to the fourth patch electrode PE4. The absolute value of the voltage V applied to each patch electrode PE is the same throughout the entire period Pd.

[0046] With the potential of the common electrode CE as the reference, the polarity of the voltage applied to each patch electrode PE is periodically reversed. For example, the patch electrodes PE are driven at a drive frequency of 60 Hz. As described above, the patch electrodes PE are AC driven.

[0047] Even when period Pd changes to another period Pd, the phase difference δ1 between the radio wave reflected in the first reflection direction d1 by one reflection control unit RH and the radio wave reflected in the first reflection direction d1 by the adjacent reflection control unit RH is maintained. In this embodiment, the phase difference δ1 is 30°. Therefore, a phase difference of 210° is given between the radio wave reflected in the first reflection direction d1 by the first reflection control unit RH1 including the first patch electrode PE1 and the radio wave reflected in the first reflection direction d1 by the eighth reflection control unit RH8 including the eighth patch electrode PE8. In this embodiment 1, the radio wave reflector RE can provide a phase difference of up to 240° between the radio waves reflected in the first reflection direction d1 by one reflection control unit RH and the radio waves reflected in the first reflection direction d1 by another reflection control unit RH.

[0048] Furthermore, the attenuation of the reflected wave amplitude was investigated for the radio wave reflector RE of this embodiment 1. The investigation revealed that the attenuation of the reflected wave amplitude was suppressed, with a maximum of -9 dB. Note that 0 dB is the case when radio waves are totally reflected by the radio wave reflector RE.

[0049] (Example 2 of the first embodiment) Next, an embodiment 2 of the first embodiment will be described. Figure 9 is an enlarged plan view showing a part of the radio wave reflector RE according to this embodiment 2, and shows multiple individual regions IA, a connection region CA, and a peripheral region PA. As shown in Figure 9, the radio wave reflector RE of this embodiment 2 differs from that of embodiment 1 in terms of the shape and dimensions of the first region A1, and the shape, dimensions, and number of the second region A2.

[0050] The first region A1 is a grid-like region and includes a frame-shaped region A1a and a grid-like region A1b that is surrounded by and connected to the frame-shaped region A1a. The frame-shaped region A1a has a square outer edge and a square inner edge. In the frame-shaped region A1a, the centroid of the outer edge and the centroid of the inner edge are the same in a plan view.

[0051] The grid region A1b comprises a plurality of first linear regions A1c and a plurality of second linear regions A1d. The plurality of first linear regions A1c extend in a direction parallel to the X-axis and are spaced apart in a direction parallel to the Y-axis. The plurality of second linear regions A1d extend in a direction parallel to the Y-axis and are spaced apart in a direction parallel to the X-axis, and intersect the plurality of first linear regions A1c.

[0052] Each individual region IA has multiple second regions A2. Each of the multiple second regions A2 is a region enclosed by a frame-shaped region A1a, multiple first linear regions A1c, and multiple second linear regions A1d, and each has a square shape.

[0053] Each frame-shaped region A1a has a length Pxa1 along the X-axis and a length Pya1 along the Y-axis. Length Pxa1 corresponds to the distance between the opposing outer and inner edges in each region of the frame-shaped region A1a that extends along the Y-axis. Length Pya1 corresponds to the distance between the opposing outer and inner edges in each region of the frame-shaped region A1a that extends along the X-axis.

[0054] Each second linear region A1d has a length Pxa2 in the direction along the X-axis, and each first linear region A1c has a length Pya2 in the direction along the Y-axis. Each of the second regions A2 has a length Pxb1 along the X-axis and a length Pyb1 along the Y-axis.

[0055] In this embodiment 2, lengths Pxa1 and Pya1 are each 50 μm (Pxa1=Pya1=50 μm). Note that lengths Pxa1 and Pya1 are identical and can be selected within the range of, for example, 50 to 70 μm. Lengths Pxa2 and Pya2 are each 25 μm (Pxa2=Pya2=25 μm). Lengths Pxb1 and Pyb1 are each 50 μm (Pxb1=Pyb1=50 μm). Lengths Px1 and Py1 are each 2.45 mm (Px1=Py1=2.45 mm).

[0056] Furthermore, lengths Px2 and Py2 are each 50 μm (Px2 = Py2 = 50 μm). Multiple individual regions IA are arranged in a first pitch along the X-axis and in a second pitch along the Y-axis. In this embodiment 2, the first and second pitches are each 2.5 mm.

[0057] In Figure 9, for the sake of clarity, five first linear regions A1c and five second linear regions A1d are shown within each individual region IA. However, as can be seen from the dimensions above, each individual region IA actually has more than five first linear regions A1c and more than five second linear regions A1d.

[0058] Figure 10 is an enlarged plan view showing multiple patch electrodes PE and multiple connecting wires L according to this second embodiment. As shown in Figure 10, each patch electrode PE has a grid-like shape and is located in the first region A1 of a corresponding individual region IA among a plurality of individual regions IA. In this embodiment 2, each patch electrode PE is located throughout the first region A1 of a corresponding individual region IA and is not located in a plurality of second regions A2. Each patch electrode PE has a first opening OP1 in its respective second region A2. In the region inside the peripheral region PA, the connecting wiring L is located in the connecting region CA.

[0059] As shown in Figures 10 and 9, each patch electrode PE comprises a first frame-shaped electrode PEa, a plurality of first linear electrodes PEb, and a plurality of second linear electrodes PEc. The first frame-shaped electrode PEa is located in a frame-shaped region A1a and has a frame-like shape. The plurality of first linear electrodes PEb are located one-to-one in the plurality of first linear regions A1c and extend in a direction parallel to the X-axis. The plurality of second linear electrodes PEc are located one-to-one in the plurality of second linear regions A1d, extend in a direction parallel to the Y-axis, intersect with the plurality of first linear electrodes PEb, and are integrally formed with the first frame-shaped electrode PEa and the plurality of first linear electrodes PEb. The shape of each patch electrode PE is 90° rotationally symmetrical in a plan view. The contour of the patch electrode PE is square.

[0060] Figure 11 is an enlarged plan view showing a part of the common electrode CE according to this embodiment 2. As shown in Figure 11, the portion of the common electrode CE located in each individual region IA has a grid-like shape, is located throughout the first region A1, and is not located in the second region A2. The portion of the common electrode CE located in each individual region IA has a second opening OP2 in each of the second regions A2.

[0061] As shown in Figures 11 and 9, the portion of the common electrode CE located in each individual region IA has a second frame-shaped electrode CEa, a plurality of third linear electrodes CEb, and a plurality of fourth linear electrodes CEc. The second frame-shaped electrode CEa is located in frame-shaped region A1a and extends parallel to the first frame-shaped electrode PEa. The plurality of third linear electrodes CEb are located one-to-one in the plurality of first linear regions A1c and extend parallel to the plurality of first linear electrodes PEb. The plurality of fourth linear electrodes CEc are located one-to-one in the plurality of second linear regions A1d, extend parallel to the plurality of second linear electrodes PEc, intersect with the plurality of third linear electrodes CEb, and are formed integrally with the second frame-shaped electrode CEa and the plurality of third linear electrodes CEb.

[0062] The shape of the portion of the common electrode CE located in each individual region IA is 90° rotationally symmetric in a plan view. In this embodiment 2, the contour of the shape of the portion of the common electrode CE located in each individual region IA is square.

[0063] As shown in Figures 9 to 11, within the peripheral region PA, the regions in which multiple patch electrodes PE and common electrode CE allow light (visible light) to pass through are multiple second regions A2, or in other words, multiple first light-transmitting regions where multiple first apertures OP1 of the patch electrodes PE and multiple second apertures OP2 of the common electrode CE overlap. In each individual region IA of this embodiment 2, the aperture ratio is substantially 40%.

[0064] In this embodiment 2, the radio wave reflector RE can provide a phase difference of up to 290° between the radio waves reflected in the first reflection direction d1 by one reflection control unit RH and the radio waves reflected in the first reflection direction d1 by another reflection control unit RH. Furthermore, the attenuation of the reflected wave amplitude was investigated for the radio wave reflector RE of this second embodiment. The investigation revealed that the attenuation of the reflected wave amplitude was suppressed, with a maximum of -9 dB.

[0065] (Example 3 of the first embodiment) Next, we will describe Embodiment 3 of the first embodiment. The radio wave reflector RE of Embodiment 3 differs from that of Embodiment 2 in terms of the shape and dimensions of the individual region IA. As shown in Figure 9, in this embodiment 3, lengths Pxa1 and Pya1 are each 50 μm (Pxa1=Pya1=50 μm). Note that lengths Pxa1 and Pya1 are identical and can be selected within the range of, for example, 50 to 70 μm. Lengths Pxa2 and Pya2 are each 30 μm (Pxa2=Pya2=30 μm). Lengths Pxb1 and Pyb1 are each 150 μm (Pxb1=Pyb1=150 μm). Lengths Px1 and Py1 are each 2.15 mm (Px1=Py1=2.15 mm).

[0066] Furthermore, the lengths Px2 and Py2 are each 50 μm (Px2 = Py2 = 50 μm). Multiple individual regions IA are arranged in a first pitch along the X-axis and in a second pitch along the Y-axis. In this embodiment 3, the first pitch and the second pitch are each 2.2 mm.

[0067] In each individual region IA of this embodiment 3, the aperture ratio is substantially 60%. In this embodiment 3, the radio wave reflector RE can provide a phase difference of up to 270° between the radio waves reflected in the first reflection direction d1 by one reflection control unit RH and the radio waves reflected in the first reflection direction d1 by another reflection control unit RH. Furthermore, the attenuation of the reflected wave amplitude was investigated for the radio wave reflector RE of this embodiment 3. The investigation revealed that the attenuation of the reflected wave amplitude was suppressed, with a maximum of -9 dB.

[0068] (Example 4 of the first embodiment) Next, Embodiment 4 of the first embodiment will be described. The radio wave reflector RE of Embodiment 4 differs from that of Embodiment 2 in terms of the shape and dimensions of the individual region IA. As shown in Figure 9, in this embodiment 4, lengths Pxa1 and Pya1 are each 50 μm (Pxa1=Pya1=50 μm). Note that lengths Pxa1 and Pya1 are identical and can be selected within the range of, for example, 50 to 70 μm. Lengths Pxa2 and Pya2 are each 25 μm (Pxa2=Pya2=25 μm). Lengths Pxb1 and Pyb1 are each 25 μm (Pxb1=Pyb1=25 μm). Lengths Px1 and Py1 are each 2.55 mm (Px1=Py1=2.55 mm).

[0069] Furthermore, the lengths Px2 and Py2 are each 50 μm (Px2 = Py2 = 50 μm). Multiple individual regions IA are arranged in a first pitch along the X-axis and in a second pitch along the Y-axis. In this embodiment 3, the first pitch and the second pitch are each 2.6 mm.

[0070] In each individual region IA of this embodiment 4, the aperture ratio is substantially 23%. In this embodiment 4, the radio wave reflector RE can provide a phase difference of up to 180° between the radio waves reflected in the first reflection direction d1 by one reflection control unit RH and the radio waves reflected in the first reflection direction d1 by another reflection control unit RH. Furthermore, the attenuation of the reflected wave amplitude was investigated for the radio wave reflector RE of this embodiment 4. The investigation revealed that the attenuation of the reflected wave amplitude was suppressed, with a maximum of -2.5 dB.

[0071] (Example 5 of the first embodiment) Next, Embodiment 5 of the first embodiment will be described. Figure 12 is an enlarged plan view showing a part of the radio wave reflector RE according to Embodiment 5, and shows multiple individual regions IA, a connection region CA, and a peripheral region PA.

[0072] As shown in Figure 12, the radio wave reflector RE of this embodiment 5 differs from that of embodiment 1 in terms of the shape and dimensions of the first region A1 and the shape, dimensions, and number of the second region A2. The first region A1 is a cross-shaped region and has a first linear region A1c and a second linear region A1d. The first linear region A1c extends in a direction parallel to the X-axis. The second linear region A1d extends in a direction parallel to the Y-axis and intersects with the first linear region A1c.

[0073] Each individual region IA has multiple secondary regions A2. These secondary regions A2 are regions enclosed by the primary region A1 and the connecting region CA, or regions enclosed by the primary region A1, the connecting region CA, and the surrounding region PA, and each has a square shape.

[0074] The second linear region A1d has a length Pxa2 in the direction along the X-axis, and the first linear region A1c has a length Pya2 in the direction along the Y-axis. Each of the second regions A2 has a length Pxb1 along the X-axis and a length Pyb1 along the Y-axis.

[0075] In this embodiment 5, lengths Pxa2 and Pya2 are each 1000 μm (Pxa2 = Pya2 = 1000 μm). Lengths Pxb1 and Pyb1 are each 1000 μm (Pxb1 = Pyb1 = 1000 μm). Lengths Px1 and Py1 are each 3.0 mm (Px1 = Py1 = 3.0 mm).

[0076] Furthermore, lengths Px2 and Py2 are each 50 μm (Px2 = Py2 = 50 μm). Multiple individual regions IA are arranged in a first pitch along the X-axis and in a second pitch along the Y-axis. In this embodiment 5, the first pitch and the second pitch are each 3.05 mm.

[0077] Figure 13 is an enlarged plan view showing multiple patch electrodes PE and multiple connecting wires L according to this embodiment 5. As shown in Figure 13, each patch electrode PE has a cross shape and is located in the first region A1 of one of the multiple individual regions IA. In this embodiment 5, each patch electrode PE is located throughout the first region A1 of the corresponding individual region IA and is not located in the multiple second regions A2.

[0078] As shown in Figures 13 and 12, each patch electrode PE has a first linear electrode PEb and a second linear electrode PEc. The first linear electrode PEb is located in the first linear region A1c and extends in a direction parallel to the X-axis. The second linear electrode PEc is located in the second linear region A1d, extends in a direction parallel to the Y-axis, intersects with the first linear electrode PEb, and is formed integrally with the first linear electrode PEb. The shape of each patch electrode PE is 90° rotationally symmetrical in a plan view.

[0079] Figure 14 is an enlarged plan view showing a part of the common electrode CE according to this embodiment 5. As shown in Figure 14, the portion of the common electrode CE located in each individual region IA has a cross shape, is located throughout the first region A1, and is not located in the second region A2.

[0080] As shown in Figures 14 and 12, the portion of the common electrode CE located in each individual region IA has a third linear electrode CEb and a fourth linear electrode CEc. The third linear electrode CEb is located in the first linear region A1c and extends parallel to a plurality of first linear electrodes PEb. The fourth linear electrode CEc is located in a plurality of second linear regions A1d, extends parallel to the second linear electrodes PEc, intersects with the third linear electrode CEb, and is formed integrally with the third linear electrode CEb. The shape of the portion of the common electrode CE located in each individual region IA is 90° rotationally symmetric in plan view.

[0081] In this embodiment 5, multiple third linear electrodes CEb arranged in a direction parallel to the X-axis are connected in the connection region CA and formed integrally. Multiple fourth linear electrodes CEc arranged in a direction parallel to the Y-axis are connected in the connection region CA and formed integrally.

[0082] As shown in Figures 12 to 14, within the peripheral region PA, the regions in which multiple patch electrodes PE and a common electrode CE allow light (visible light) to pass through are multiple second regions A2 and the regions within the connecting region CA where the common electrode CE is not formed. In other words, these are multiple first light-transmitting regions overlapping multiple second regions A2 and multiple second light-transmitting regions within the connecting region CA where the common electrode CE is not formed. In each individual region IA of this embodiment 5, the aperture ratio is substantially 44%.

[0083] In this embodiment 5, the radio wave reflector RE can provide a phase difference of up to 240° between the radio waves reflected in the first reflection direction d1 by one reflection control unit RH and the radio waves reflected in the first reflection direction d1 by another reflection control unit RH. Furthermore, the attenuation of the reflected wave amplitude was investigated for the radio wave reflector RE of this embodiment 5. The investigation revealed that the attenuation of the reflected wave amplitude was suppressed, with a maximum of -9 dB.

[0084] According to the radio wave reflector RE of the first embodiment configured as described above, the radio wave reflector RE is equipped with a plurality of reflection control units RH. Radio waves in the 28GHz band used in 5G (fifth-generation mobile communication system) have strong directivity, so the communication environment deteriorates if there are obstacles (coverage holes). Therefore, as a countermeasure, a radio wave reflector RE can be placed and the reflected wave w2 can be utilized. Since the direction of the reflected wave w2 can be controlled by the radio wave reflector RE, it can respond to changes in the radio wave environment.

[0085] Each reflection control unit RH has a region in its individual region IA that allows light (visible light) to pass through. In other words, the individual region IA has a region where neither the patch electrode PE nor the common electrode CE is formed. The radio wave reflector RE can transmit visible light in the second region A2. When the radio wave reflector RE is placed in an environment, it can be made to blend into the landscape. For example, a person looking at the radio wave reflector RE can see the background behind the radio wave reflector RE through the reflector RE. From the above, it is possible to obtain a radio wave reflector RE with excellent light transmittance.

[0086] Assuming a frequency band of 28 GHz for the incident wave w1, the patterns of the patch electrode PE and common electrode CE in the individual region IA are not specific and can be varied in various ways, as illustrated in Examples 1 to 5 above. For example, in Examples 1 to 5 above, Example 1 is the embodiment in which the pitch of the multiple individual regions IA is minimized. Therefore, Example 1 is advantageous for increasing the resolution of the multiple reflection control units RH.

[0087] On the other hand, among the above embodiments 1 to 5, embodiment 5 is the embodiment in which the pitch of the multiple individual regions IA is maximized. Therefore, embodiment 5 is advantageous for increasing the size of the radio wave reflector RE.

[0088] (Modified version of the first embodiment) Next, a modified version of the first embodiment will be described. Figure 15 is an enlarged plan view showing a part of the radio wave reflector RE according to this modified version, and shows multiple individual regions IA, a connection region CA, and a peripheral region PA. As shown in Figure 15, the radio wave reflector RE of this modified example differs from that of the above-described embodiment 2 in terms of the shape of the first region A1 and the number of the second region A2.

[0089] The first region A1 comprises a frame-shaped region A1a, a first linear region A1c, and a second linear region A1d. The multiple second regions A2 are areas enclosed by the frame-shaped region A1a, the first linear region A1c, and the second linear region A1d, and each has a square shape.

[0090] Figure 16 is an enlarged plan view showing multiple patch electrodes PE and multiple connecting wires L according to this modified example. As shown in Figure 16, each patch electrode PE is located in the first region A1 of a corresponding individual region IA among multiple individual regions IA. In this modified example, each patch electrode PE is located in the entire frame-shaped region A1a of the corresponding individual region IA, in a part of the first linear region A1c, in a part of the second linear region A1d, and not in any of the multiple second regions A2.

[0091] As shown in Figures 16 and 15, each patch electrode PE has a first frame-shaped electrode PEa, a plurality of first linear electrodes PEb, and a plurality of second linear electrodes PEc. In this modified example, each patch electrode PE has three first linear electrodes PEb and three second linear electrodes PEc.

[0092] Multiple first linear electrodes PEb are located in the first linear region A1c, extending in a direction parallel to the X-axis and spaced apart in a direction parallel to the Y-axis. Multiple second linear electrodes PEc are located in the second linear region A1d, extending in a direction parallel to the Y-axis and spaced apart in a direction parallel to the X-axis, intersecting with the multiple first linear electrodes PEb, and are integrally formed with the first frame electrode PEa and the multiple first linear electrodes PEb. The shape of each patch electrode PE is 90° rotationally symmetrical in a plan view. The contour of the patch electrode PE is square.

[0093] Figure 17 is an enlarged plan view showing a part of the common electrode CE according to this modified example. As shown in Figure 17, the parts of the common electrode CE located in each individual region IA are located in the entire frame-shaped region A1a, in a part of the first linear region A1c, in a part of the second linear region A1d, and not in any of the multiple second regions A2.

[0094] As shown in Figures 17 and 15, the portion of the common electrode CE located in each individual region IA has a second frame-shaped electrode CEa, a plurality of third linear electrodes CEb, and a plurality of fourth linear electrodes CEc. In this modified example, the portion of the common electrode CE located in each individual region IA has three third linear electrodes CEb and three fourth linear electrodes CEc.

[0095] Multiple third linear electrodes CEb are located in the first linear region A1c and extend parallel to multiple first linear electrodes PEb. In a plan view, each third linear electrode CEb overlaps with its corresponding first linear electrode PEb.

[0096] Multiple fourth linear electrodes CEc are located within multiple second linear regions A1d, extend parallel to multiple second linear electrodes PEc, intersect with multiple third linear electrodes CEb, and are integrally formed with the second frame electrode CEa and the multiple third linear electrodes CEb. In a plan view, each fourth linear electrode CEc overlaps with the corresponding second linear electrode PEc. The shape of the portion of the common electrode CE located in each individual region IA is 90° rotationally symmetric in a plan view.

[0097] As shown in Figures 15 to 17, within the peripheral region PA, the regions in which multiple patch electrodes PE and common electrodes CE allow light (visible light) to pass through are multiple second regions A2 and regions within each first region A1 in which multiple first linear electrodes PEb, multiple second linear electrodes PEc, multiple third linear electrodes CEb, and multiple fourth linear electrodes CEc are not formed. In this modified example, the same effects as those of the first embodiment described above can be obtained.

[0098] (Second embodiment) Next, a second embodiment will be described. The radio wave reflector RE is configured in the same way as in Embodiment 1 of the first embodiment, except for the configuration described in this embodiment. Figure 18 is a plan view showing the radio wave reflector RE according to this embodiment. In the figure, a dot pattern is applied to the sealing material SE, and diagonal lines are applied to the multiple patch electrodes PE.

[0099] As shown in Figure 18, the first substrate SUB1 has multiple signal lines SL, multiple control lines GL, multiple switching elements SW, a drive circuit DR, a drive circuit DC, and multiple lead wires LE instead of connection lines L and lines WL.

[0100] Multiple signal lines SL extend along the Y-axis and are aligned along the X-axis. Signal lines SL are connected to drive circuit DC. Multiple control lines GL extend along the X-axis and are aligned along the Y-axis. Signal lines SL and control lines GL extend within the region enclosed by peripheral region PA. Drive circuit DR is located in peripheral region PA. Multiple control lines GL are connected to drive circuit DR.

[0101] The switching element SW is located near the intersection of one signal wire SL and one control wire GL, and is electrically connected to both the signal wire SL and the control wire GL. Multiple lead wires LE are connected to the drive circuit DR on one end and to the pad p of the OLB on the other end. The lead wires LE may also be connected to the drive circuit DC.

[0102] Figure 19 is an enlarged cross-sectional view showing a part of the radio wave reflector RE according to this second embodiment. As shown in Figure 19, insulating layers 11, 12, 13, 14, 15, 16, 17, and an alignment film AL1 are formed in order on the substrate 1. Insulating layers 11 to 17 are either inorganic insulating layers or organic insulating layers. In this embodiment, insulating layer 16 is an organic insulating layer and is formed of, for example, a resin.

[0103] Insulating layers 11 to 15 and 17 are each inorganic insulating layers. Insulating layer 11 is made of SiO (silicon oxide). Insulating layer 12 has a lower layer made of SiN (silicon nitride) and an upper layer made of SiO. Insulating layer 13 is made of SiO. Insulating layer 14 is made of SiN. Insulating layer 15 is made of SiO or SiN. Insulating layer 17 is made of SiN.

[0104] The control wiring GL and conductive layer CO1 are provided on an insulating layer 11 and covered with an insulating layer 12. A semiconductor layer SMC is provided on the insulating layer 12. The semiconductor layer SMC is superimposed on the control wiring GL. The semiconductor layer SMC is formed of an oxide semiconductor (OS), which is a transparent semiconductor. Typical examples of oxide semiconductors include indium gallium zinc oxide (InGaZnO), indium gallium oxide (InGaO), indium zinc oxide (InZnO), zinc tin oxide (ZnSnO), zinc oxide (ZnO), and transparent amorphous oxide semiconductor (TAOS). However, the semiconductor layer SMC is not limited to an oxide semiconductor and may be formed of amorphous silicon or low-temperature polycrystalline silicon as polycrystalline silicon.

[0105] The conductive layer CO2 and the connecting wiring layer CL1 are provided on the insulating layer 12 and the semiconductor layer SMC, and are covered with the insulating layer 13. The connecting wiring layer CL1 contacts the conductive layer CO1 through contact holes formed in the insulating layer 12. The conductive layer CO2 and the connecting wiring layer CL1 are in contact with the semiconductor layer SMC and are electrically connected. Of the regions in the semiconductor layer SMC to which the conductive layer CO2 is connected and the regions to which the connecting wiring layer CL1 is connected, one is the source region and the other is the drain region. The semiconductor layer SMC has a channel region between the source region and the drain region.

[0106] The gate electrode GE is provided on the insulating layer 13 and covered by the insulating layer 14. The gate electrode GE is electrically connected to the control wiring GL. The gate electrode GE overlaps at least the channel region of the semiconductor layer SMC. The control wiring GL, semiconductor layer SMC, gate electrode GE, etc., constitute a switching element SW as a TFT (thin film transistor).

[0107] The region of the control wiring GL that overlaps with the semiconductor layer SMC functions as a gate electrode. Therefore, the switching element SW is a dual-gate type TFT. However, the switching element SW may also be a bottom-gate type TFT or a top-gate type TFT.

[0108] The conductive layer CO3 and the connecting wiring layer CL2 are provided on the insulating layer 14 and covered by the insulating layer 15. The conductive layer CO3 contacts the gate electrode GE through contact holes formed in the insulating layer 14. The connecting wiring layer CL2 contacts the connecting wiring layer CL1 through contact holes formed in the insulating layers 13 and 14.

[0109] Insulating layers 16 and 17 are provided sequentially on insulating layer 15. The patch electrode PE is provided on insulating layer 17 and is covered with the alignment film AL1. The patch electrode PE contacts the connecting wiring layer CL2 through contact holes formed in insulating layers 15, 16, and 17.

[0110] A common electrode CE and an alignment film AL2 are provided in order on the surface of the substrate 2 facing the first substrate SUB1. The control wiring GL, conductive layers CO1, CO2, CO3, connecting wiring layers CL1, CL2, and gate electrode GE are formed of metal as a low-resistance conductive material. The control wiring GL and gate electrode GE may be formed of Mo (molybdenum), W (tungsten), or alloys thereof. The connecting wiring layers CL1, CL2 may be formed of TAT or MAM.

[0111] The above-mentioned MAM has a three-layer laminated structure (Mo-based / Al-based / Mo-based), comprising a lower layer made of a metallic material mainly composed of Mo, such as Mo or alloys containing Mo; an intermediate layer made of a metallic material mainly composed of Al, such as Al or alloys containing Al; and an upper layer made of a metallic material mainly composed of Mo, such as Mo or alloys containing Mo.

[0112] As shown in Figures 18 and 19, multiple patch electrodes PE can be driven individually by active matrix driving. Therefore, multiple patch electrodes PE can be driven independently. For example, the direction of the reflected wave w2 reflected by the radio wave reflector RE can be set to a direction parallel to the YZ plane. Alternatively, the direction of the reflected wave w2 reflected by the radio wave reflector RE can be set to a direction parallel to a third plane other than the XZ plane and the YZ plane. The third plane is defined by the Z axis and a third axis other than the X and Y axes in the XY plane.

[0113] Figure 20 is an enlarged plan view showing a plurality of patch electrodes PE according to the second embodiment of this invention, and is a diagram for illustrating an example of the voltage applied to the plurality of patch electrodes PE in the driving method of the radio wave reflector RE. As shown in Figure 20, the reflection direction d of the reflected wave w2 reflected by the radio wave reflector RE can be tilted 45° downwards to the right. The voltages V applied to the patch electrodes PE are the first voltage V1, the second voltage V2, ..., the seventh voltage V7.

[0114] Figure 21 is an enlarged plan view showing a plurality of patch electrodes PE according to this second embodiment, and is a diagram for illustrating another example of the voltage applied to the plurality of patch electrodes PE in the method of driving the radio wave reflector RE. As shown in Figure 21, the reflection direction d of the reflected wave w2 reflected by the radio wave reflector RE can be tilted to the upper left at 22.5°. The voltages V applied to the patch electrodes PE are the first voltage V1, the second voltage V2, ..., the seventh voltage V7.

[0115] According to the radio wave reflector RE of the second embodiment configured as described above, the same effects as in Example 1 of the first embodiment can be obtained. Since each patch electrode PE can be driven independently, the degree of freedom of the reflection direction d of the reflected wave w2 reflected by the radio wave reflector RE can be increased.

[0116] (Modified version of the second embodiment) Next, a modification of the second embodiment will be described. This modification of the second embodiment is the same as Example 5 (Figure 12) of the first embodiment with respect to the multiple individual regions IA, connection region CA, and peripheral region PA.

[0117] Figure 22 is an enlarged plan view showing multiple patch electrodes PE of the radio wave reflector RE according to this modified example. As shown in Figure 22, the first region A1 is a cross-shaped region and has a first linear region A1c extending in a direction parallel to the X-axis and a second linear region A1d extending in a direction parallel to the Y-axis and intersecting the first linear region A1c.

[0118] Each patch electrode PE has a plurality of first linear electrodes PEb and a plurality of second linear electrodes PEc. The plurality of first linear electrodes PEb are located in the first linear region A1c, extending in a direction parallel to the X-axis and spaced apart in a direction parallel to the Y-axis. The plurality of second linear electrodes PEc are located in the second linear region A1d, extending in a direction parallel to the Y-axis and spaced apart in a direction parallel to the X-axis, intersecting with the plurality of first linear electrodes PEb and being formed integrally with the plurality of first linear electrodes PEb.

[0119] Figure 23 is an enlarged plan view showing a part of the common electrode CE of the radio wave reflector RE according to this modified example. As shown in Figure 23, the portion of the common electrode CE located in each individual region IA has a plurality of third linear electrodes CEb and a plurality of fourth linear electrodes CEc.

[0120] Multiple third linear electrodes CEb are located in the first linear region A1c and extend parallel to multiple first linear electrodes PEb. In a plan view, each third linear electrode CEb overlaps with its corresponding first linear electrode PEb.

[0121] Multiple fourth linear electrodes CEc are located in the second linear region A1d, extend parallel to multiple second linear electrodes PEc, intersect with multiple third linear electrodes CEb, and are integrally formed with multiple third linear electrodes CEb. In a plan view, each fourth linear electrode CEc overlaps with the corresponding second linear electrode PEc.

[0122] The portion of the common electrode CE located in each individual region IA has a third linear electrode CEb and a fourth linear electrode CEc. The third linear electrode CEb is located in the first linear region A1c and extends parallel to multiple first linear electrodes PEb. The fourth linear electrode CEc is located in multiple second linear regions A1d, extends parallel to the second linear electrodes PEc, intersects with the third linear electrode CEb, and is formed integrally with the third linear electrode CEb. The shape of the portion of the common electrode CE located in each individual region IA is 90° rotationally symmetric in plan view.

[0123] In this modified example, multiple third linear electrodes CEb arranged in a direction parallel to the X-axis are connected in the connection region CA and formed integrally. Multiple fourth linear electrodes CEc arranged in a direction parallel to the Y-axis are connected in the connection region CA and formed integrally. In this modified example, the same effects as those of the second embodiment described above can be obtained.

[0124] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0125] For example, the radio wave reflector RE of the second embodiment may be fitted with the patch electrode PE and common electrode CE according to each embodiment and modification of the first embodiment. The radio wave reflector RE of the first embodiment may be fitted with the patch electrode PE and common electrode CE according to a modification of the second embodiment.

[0126] In the first embodiment described above, the wires for connecting multiple patch electrodes PE are not limited to the connection wiring L in the same layer as the patch electrodes PE. The wires for connecting adjacent patch electrodes PE may be bridge wiring in a different layer from the patch electrodes PE. The bridge wiring is connected to one patch electrode PE through a contact hole and to the other patch electrode PE through another contact hole.

[0127] The liquid crystal mode used in the radio wave reflector RE can be any mode that allows a longitudinal electric field to be applied to the liquid crystal layer (LC). Therefore, TN (Twisted Nematic) mode, ECB (Electrically Controlled Birefringence) mode, or π-cell can be applied to the radio wave reflector RE.

Claims

1. A plurality of individual regions arranged in a matrix along mutually orthogonal X and Y axes, each of which comprises a first region and one or more second regions other than the first region, A connecting region located in the gap between the plurality of individual regions, having a grid-like shape and connected to the plurality of individual regions, A first substrate having a plurality of patch electrodes, wherein each patch electrode is located in a first region of a corresponding individual region among the plurality of individual regions, A second substrate having a common electrode, wherein the common electrode is located in the first region and the connection region of each of the individual regions and faces the plurality of patch electrodes in a direction parallel to the Z axis which is perpendicular to the X axis and the Y axis, respectively, the second substrate, A radio wave reflector comprising a liquid crystal layer held between the first substrate and the second substrate and facing the plurality of patch electrodes.

2. The radio wave reflector according to claim 1, wherein the plurality of patch electrodes and the common electrode are each made of metal.

3. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes has the cross shape and is located in the first region. The radio wave reflector according to claim 2, wherein the portion of the common electrode located in each of the individual regions has the cross shape and is located in the first region.

4. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes is A plurality of first linear electrodes located in the first linear region, extending in a direction parallel to the X-axis and arranged at intervals in a direction parallel to the Y-axis, The second linear region includes a plurality of second linear electrodes located in the second linear region, extending in a direction parallel to the Y-axis, arranged at intervals in a direction parallel to the X-axis, intersecting with the plurality of first linear electrodes, and being integrally formed with the plurality of first linear electrodes. The portion of the common electrode located in each of the individual regions is, A plurality of third linear electrodes located in the first linear region and extending parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 2, further comprising: a plurality of fourth linear electrodes located in the second linear region, extending parallel to the plurality of second linear electrodes, intersecting the plurality of third linear electrodes, and integrally formed with the plurality of third linear electrodes.

5. The first region is a frame-shaped region, The second region is the region enclosed by the first region, Each of the aforementioned patch electrodes has the frame-like shape and is located in the first region. The radio wave reflector according to claim 2, wherein the portion of the common electrode located in each of the individual regions has the frame shape and is located in the first region.

6. The first region is a grid-like region, comprising a frame-shaped region and a grid-like region surrounded by the frame-shaped region and connected to the frame-shaped region. The grid-like region comprises a plurality of first linear regions extending in a direction parallel to the X-axis and spaced apart in a direction parallel to the Y-axis, and a plurality of second linear regions extending in a direction parallel to the Y-axis and spaced apart in a direction parallel to the X-axis, intersecting the plurality of first linear regions. Each of the aforementioned patch electrodes is A first frame-shaped electrode located in the frame-shaped region and having a frame-shaped shape, A plurality of first linear electrodes are positioned one-to-one in the plurality of first linear regions and extend in a direction parallel to the X-axis, It has a plurality of second linear electrodes that are positioned one-to-one in the plurality of second linear regions, extend in a direction parallel to the Y axis, intersect with the plurality of first linear electrodes, and are integrally formed with the first frame electrode and the plurality of first linear electrodes, The portion of the common electrode located in each of the individual regions is, A second frame-shaped electrode located in the frame-shaped region and extending parallel to the first frame-shaped electrode, A plurality of third linear electrodes are positioned one-to-one in the plurality of first linear regions and extend parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 2, further comprising: a plurality of fourth linear electrodes positioned one-to-one in the plurality of second linear regions, extending parallel to the plurality of second linear electrodes, intersecting the plurality of third linear electrodes, and integrally formed with the second frame electrode and the plurality of third linear electrodes.

7. The shape of the portion of the common electrode located in each of the individual regions is the same as the shape of each of the patch electrodes. The radio wave reflector according to claim 1, wherein the portion of the common electrode located in each of the individual regions overlaps with a corresponding patch electrode among the plurality of patch electrodes in a plan view.

8. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes has the cross shape and is located in the first region. The radio wave reflector according to claim 7, wherein the portion of the common electrode located in each of the individual regions has the cross shape and is located in the first region.

9. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes is A plurality of first linear electrodes located in the first linear region, extending in a direction parallel to the X-axis and arranged at intervals in a direction parallel to the Y-axis, The second linear region includes a plurality of second linear electrodes located in the second linear region, extending in a direction parallel to the Y-axis, arranged at intervals in a direction parallel to the X-axis, intersecting with the plurality of first linear electrodes, and being integrally formed with the plurality of first linear electrodes. The portion of the common electrode located in each of the individual regions is, A plurality of third linear electrodes located in the first linear region and extending parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 7, comprising: a plurality of fourth linear electrodes located in the second linear region, extending parallel to the plurality of second linear electrodes, intersecting the plurality of third linear electrodes, and integrally formed with the plurality of third linear electrodes.

10. The first region is a frame-shaped region, The second region is the region enclosed by the first region, Each of the aforementioned patch electrodes has the frame-like shape and is located in the first region. The radio wave reflector according to claim 7, wherein the portion of the common electrode located in each of the individual regions has the frame shape and is located in the first region.

11. The first region is a grid-like region, comprising a frame-shaped region and a grid-like region surrounded by the frame-shaped region and connected to the frame-shaped region. The grid-like region comprises a plurality of first linear regions extending in a direction parallel to the X-axis and spaced apart in a direction parallel to the Y-axis, and a plurality of second linear regions extending in a direction parallel to the Y-axis and spaced apart in a direction parallel to the X-axis, intersecting the plurality of first linear regions. Each of the aforementioned patch electrodes is A first frame-shaped electrode located in the frame-shaped region and having a frame-shaped shape, A plurality of first linear electrodes are positioned one-to-one in the plurality of first linear regions and extend in a direction parallel to the X-axis, It has a plurality of second linear electrodes that are positioned one-to-one in the plurality of second linear regions, extend in a direction parallel to the Y axis, intersect with the plurality of first linear electrodes, and are integrally formed with the first frame electrode and the plurality of first linear electrodes, The portion of the common electrode located in each of the individual regions is, A second frame-shaped electrode located in the frame-shaped region and extending parallel to the first frame-shaped electrode, A plurality of third linear electrodes are positioned one-to-one in the plurality of first linear regions and extend parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 7, comprising: a plurality of fourth linear electrodes positioned one-to-one in the plurality of second linear regions, extending parallel to the plurality of second linear electrodes, intersecting the plurality of third linear electrodes, and integrally formed with the second frame electrode and the plurality of third linear electrodes.

12. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes has the cross shape and is located in the first region. The radio wave reflector according to claim 1, wherein the portion of the common electrode located in each of the individual regions has the cross shape and is located in the first region.

13. The first region is a cross-shaped region, comprising a first linear region extending in a direction parallel to the X-axis and a second linear region extending in a direction parallel to the Y-axis and intersecting the first linear region. Each of the aforementioned patch electrodes is A plurality of first linear electrodes located in the first linear region, extending in a direction parallel to the X-axis and arranged at intervals in a direction parallel to the Y-axis, The second linear region includes a plurality of second linear electrodes located in the second linear region, extending in a direction parallel to the Y-axis, arranged at intervals in a direction parallel to the X-axis, intersecting with the plurality of first linear electrodes, and being integrally formed with the plurality of first linear electrodes. The portion of the common electrode located in each of the individual regions is, A plurality of third linear electrodes located in the first linear region and extending parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 1, further comprising: a plurality of fourth linear electrodes located in the second linear region, extending parallel to the plurality of second linear electrodes, intersecting with the plurality of third linear electrodes, and integrally formed with the plurality of third linear electrodes.

14. The first region is a frame-shaped region, The second region is the region enclosed by the first region, Each of the aforementioned patch electrodes has the frame-like shape and is located in the first region. The radio wave reflector according to claim 1, wherein the portion of the common electrode located in each of the individual regions has the frame shape and is located in the first region.

15. The first region is a grid-like region, comprising a frame-shaped region and a grid-like region surrounded by the frame-shaped region and connected to the frame-shaped region. The grid-like region comprises a plurality of first linear regions extending in a direction parallel to the X-axis and spaced apart in a direction parallel to the Y-axis, and a plurality of second linear regions extending in a direction parallel to the Y-axis and spaced apart in a direction parallel to the X-axis, intersecting the plurality of first linear regions. Each of the aforementioned patch electrodes is A first frame-shaped electrode located in the frame-shaped region and having a frame-shaped shape, A plurality of first linear electrodes are positioned one-to-one in the plurality of first linear regions and extend in a direction parallel to the X-axis, It has a plurality of second linear electrodes that are positioned one-to-one in the plurality of second linear regions, extend in a direction parallel to the Y axis, intersect with the plurality of first linear electrodes, and are integrally formed with the first frame electrode and the plurality of first linear electrodes, The portion of the common electrode located in each of the individual regions is, A second frame-shaped electrode located in the frame-shaped region and extending parallel to the first frame-shaped electrode, A plurality of third linear electrodes are positioned one-to-one in the plurality of first linear regions and extend parallel to the plurality of first linear electrodes, The radio wave reflector according to claim 1, further comprising: a plurality of fourth linear electrodes positioned one-to-one in the plurality of second linear regions, extending parallel to the plurality of second linear electrodes, intersecting the plurality of third linear electrodes, and integrally formed with the second frame electrode and the plurality of third linear electrodes.

16. The radio wave reflector according to claim 1, wherein the shape of each of the patch electrodes and the common electrode located in each of the individual regions is 90° rotationally symmetrical in a plan view.

17. The radio wave reflector according to claim 16, wherein the outline of the shape is square.

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