Radio wave reflector and phased array antenna

Abstract

Provided are a radio wave-reflecting plate and a phased array antenna which have high product reliability.　The radio wave-reflecting plate is equipped with a first substrate, a second substrate, a sealing material, a liquid crystal layer and a first transfer. The first substrate has a plurality of patch electrodes and a first power supply pad. The second substrate has a common electrode and a first power-receiving pad which is electrically connected to the common electrode. The first transfer contacts the first power supply pad and the first power-receiving pad. The first power supply pad uppermost layer which contacts the first transfer is formed from a transparent conductive material. The first power-receiving pad is formed from a transparent conductive material.

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a radio wave reflector and a phased array antenna. [Background technology]

[0002] Phase shifters using liquid crystals are being developed for use in phased array antennas, which can electrically control directivity. In phased array antennas, multiple antenna elements to which high-frequency signals are transmitted from corresponding phase shifters are arranged one-dimensionally (or two-dimensionally). In such phased array antennas, the dielectric constant of the liquid crystal needs to be adjusted so that the phase difference between the high-frequency signals input to adjacent antenna elements is constant.

[0003] In addition, research is also being conducted into radio wave reflectors that can control the direction of radio wave reflection using liquid crystals, similar to phased array antennas. In these radio wave reflectors, reflection control sections with reflective electrodes are arranged one-dimensionally (or two-dimensionally). In radio wave reflectors, too, 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 sections. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-103201 [Patent Document 2] Special Publication No. 2019-530387 Summary of the Invention [Problem to be solved by the invention]

[0005] The present embodiment provides a radio wave reflector and a phased array antenna with high product reliability. [Means for solving the problem]

[0006] The radio wave reflector according to one embodiment includes: a first substrate having a plurality of patch electrodes located in a first region and arranged in a matrix at intervals along X-axis and Y-axis perpendicular to each other, and a first power supply pad located in a second region outside the first region; a second substrate including: a common electrode located in the first region and facing the plurality of patch electrodes in a direction parallel to a Z-axis that is orthogonal to each of the X-axis and the Y-axis; and a first power receiving pad located in the second region and electrically connected to the common electrode and overlapping the first power supply pad in a direction parallel to the Z-axis; a sealant located in the second region and joining the first substrate and the second substrate; a liquid crystal layer held between the first substrate and the second substrate and surrounded by the sealing material; a first transfer in contact with the first power supply pad and the first power receiving pad; a top layer of the first power supply pad that contacts the first transfer is made of a transparent conductive material; the first power receiving pad is made of a transparent conductive material; The common electrode is made of a metal.

[0007] Moreover, the phased array antenna according to one embodiment includes: a first substrate having a plurality of antennas located in a radiation region and spaced apart along an X axis, a plurality of electrically independent phase control electrodes located in a phase control region adjacent to the radiation region, and a first power supply pad located in a non-radiative region outside the radiation region and the phase control region; a second substrate including: a common electrode located in the phase control region and facing the plurality of phase control electrodes in a direction parallel to a Z axis perpendicular to the X axis; and a first power receiving pad located in the non-radiative region and electrically connected to the common electrode and overlapping the first power supply pad in a direction parallel to the Z axis; a sealing material surrounding the phase control region and joining the first substrate and the second substrate; a liquid crystal layer held between the first substrate and the second substrate and surrounded by the sealing material; a first transfer in contact with the first power supply pad and the first power receiving pad; a top layer of the first power supply pad that contacts the first transfer is made of a transparent conductive material; the first power receiving pad is made of a transparent conductive material; The common electrode is made of a metal. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a radio wave reflector according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing the radio wave reflector shown in FIG. [Figure 3] FIG. 3 is a plan view showing the radio wave reflector, illustrating the common electrode, the transparent conductive layer, the power supply pad, and the like. [Figure 4] FIG. 4 is a cross-sectional view showing the radio wave reflector taken along line IV-IV in FIG. [Figure 5] FIG. 5 is an enlarged plan view showing the patch electrode shown in FIGS. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing a part of the radio wave reflector, and shows a single reflection control section. [Figure 7] FIG. 7 is an enlarged cross-sectional view showing a part of the radio wave reflector, and shows a plurality of reflection control sections. [Figure 8] FIG. 8 is a timing chart showing the change in voltage applied to the patch electrode for each period in the method for driving the radio wave reflector of the above embodiment. [Figure 9] FIG. 9 is a plan view showing a radio wave reflector according to Modification 1 of the first embodiment, showing a common electrode, a transparent conductive layer, a power supply pad, and the like. [Figure 10] FIG. 10 is a cross-sectional view showing the second substrate of the radio wave reflector taken along line XX in FIG. [Figure 11] FIG. 11 is a plan view showing a radio wave reflector according to the second embodiment. [Figure 12]FIG. 12 is an enlarged cross-sectional view showing a part of the radio wave reflector according to the second embodiment. [Figure 13] FIG. 13 is an enlarged cross-sectional view showing a part of the phased array antenna according to the third embodiment. [Figure 14] FIG. 14 is a plan view showing the phased array antenna. [Figure 15] FIG. 15 is a plan view showing the phased array antenna, illustrating the common electrode, transparent conductive layer, power supply pad, etc. [Figure 16] FIG. 16 is a cross-sectional view showing the phased array antenna taken along line XVI-XVI in FIG. [Figure 17] FIG. 17 is a plan view showing a phased array antenna according to a first modification of the third embodiment, showing a common electrode, a transparent conductive layer, a power supply pad, and the like. [Figure 18] FIG. 18 is a cross-sectional view showing the second substrate of the phased array antenna taken along line XVIII-XVIII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings will be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] (First embodiment) First, a first embodiment will be described. Fig. 1 is a cross-sectional view showing a radio wave reflector RE according to this embodiment. The radio wave reflector RE can reflect radio waves and functions as a relay device for radio waves.

[0011] As shown in Fig. 1, the radio wave reflector RE includes a first substrate SUB1, a second substrate SUB2, and a liquid crystal layer LC. The first substrate SUB1 includes 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 an XY plane including an X-axis and a Y-axis that are orthogonal to each other. The alignment film AL1 covers the plurality of patch electrodes PE.

[0012] The second substrate SUB2 is disposed opposite the first substrate SUB1 with a predetermined gap therebetween. 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 base material 1 and the base material 2 are made of glass. However, the base material 1 and the base material 2 may be made of an insulating material other than glass, such as resin.

[0013] The common electrode CE faces the patch electrodes PE in a direction parallel to the Z axis, which is orthogonal to both the X axis and the Y axis. The alignment film AL2 covers the common electrode CE. In this embodiment, the alignment films AL1 and AL2 are both horizontal alignment films.

[0014] The first substrate SUB1 and the second substrate SUB2 are joined together by a sealant SE disposed on their respective peripheries. A liquid crystal layer LC is provided in a space surrounded by the first substrate SUB1, the second substrate SUB2, and the sealant SE. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2. One side of the liquid crystal layer LC faces a plurality of patch electrodes PE, and the other side faces a common electrode CE.

[0015] Here, the thickness of the liquid crystal layer LC (cell gap) is d l The thickness d l is larger than the thickness of the liquid crystal layer of a normal liquid crystal display panel, and is, for example, about 5 to 20 times the thickness of a normal liquid crystal display device. l However, if the reflection phase of the radio wave can be adjusted sufficiently, the thickness dl Alternatively, the thickness d may be less than 50 μm in order to increase the reflection angle of the radio wave. 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. The reflection phase of the radio wave mentioned above will be described later.

[0016] 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 0 V. A voltage is also applied to the patch electrode PE. In this embodiment, the patch electrode PE is driven by an AC current. The liquid crystal layer LC is driven by a so-called vertical electric field. The voltage applied between the patch electrode PE and the common electrode CE acts on the liquid crystal layer LC, changing the dielectric constant of the liquid crystal layer LC.

[0017] When the dielectric constant of the liquid crystal layer LC changes, the propagation speed of the radio waves in the liquid crystal layer LC also changes. Therefore, by adjusting the voltage applied to the liquid crystal layer LC, the reflection phase of the radio waves can be adjusted. Ultimately, the reflection direction of the radio waves can be adjusted. In this embodiment, the absolute value of the voltage applied to the liquid crystal layer LC is 10 V or less. This is because the dielectric constant of the liquid crystal layer LC becomes saturated at 10 V. However, the absolute value of the voltage applied to the liquid crystal layer LC may exceed 10 V. For example, if an improvement in the response speed of the liquid crystal is required, a voltage exceeding 10 V may be applied to the liquid crystal layer LC, and then a voltage of 10 V or less may be applied to the liquid crystal layer LC. The first substrate SUB1 has an incident surface Sa on the side opposite to the side facing the second substrate SUB2. In the figure, an incident wave w1 is a radio wave incident on the radio wave reflector RE, and a reflected wave w2 is a radio wave reflected by the radio wave reflector RE.

[0018] Fig. 2 is a plan view showing the radio wave reflector RE shown in Fig. 1. As shown in Fig. 2, a plurality of patch electrodes PE are arranged in a matrix at intervals along both the X-axis and the Y-axis. In the XY plane, the plurality of patch electrodes PE have the same shape and the same size.

[0019] The plurality of patch electrodes PE are located in the reflection area RA, and are arranged at equal intervals along the X-axis and at equal intervals along the Y-axis. The plurality of patch electrodes PE are included in a plurality of patch electrode groups GP that extend along the Y-axis and are arranged along the X-axis. The plurality of patch electrode groups GP include a first patch electrode group GP1 to an eighth patch electrode group GP8.

[0020] The first patch electrode group GP1 has a plurality of first patch electrodes PE1, the second patch electrode group GP2 has a plurality of second patch electrodes PE2, the third patch electrode group GP3 has a plurality of third patch electrodes PE3, the fourth patch electrode group GP4 has a plurality of fourth patch electrodes PE4, the fifth patch electrode group GP5 has a plurality of fifth patch electrodes PE5, the sixth patch electrode group GP6 has a plurality of sixth patch electrodes PE6, the seventh patch electrode group GP7 has a plurality of seventh patch electrodes PE7, and the eighth patch electrode group GP8 has a plurality of 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.

[0021] Each patch electrode group GP includes a plurality of patch electrodes PE arranged along the Y-axis and electrically connected to one another. In this embodiment, the plurality of patch electrodes PE of each patch electrode group GP are electrically connected by connection wiring L. The first substrate SUB1 has a plurality of connection wirings L extending along the Y-axis and arranged along the X-axis. The connection wirings L extend to an area of ​​the base material 1 that does not face the second substrate SUB2. Unlike this embodiment, the plurality of connection wirings L may be connected one-to-one to the plurality of patch electrodes PE.

[0022] A driving circuit DC is mounted on the first substrate SUB1 in an area that does not face the second substrate SUB2. The driving circuit DC is composed of an integrated circuit. Each wiring WL connects one connection wiring L to the driving circuit DC. The driving circuit DC is connected to an outer lead bonding (OLB) pad p.

[0023] In this embodiment, the patch electrodes PE, the connection wiring L, and the wiring WL arranged along the Y-axis are integrally formed of the same conductor. The patch electrodes PE, the connection wiring L, and the wiring WL may be formed of different conductors. The patch electrodes PE, the connection wiring L, the wiring WL, and the common electrode CE are formed of metal or a conductor equivalent to metal. For example, the patch electrodes PE, the connection wiring L, and the wiring WL may be formed of a transparent conductive material such as ITO (indium tin oxide).

[0024] The connection line L is a thin wire, and its width is sufficiently smaller than the length Px described below. The width of the connection line L is on the order of micrometers, ranging from several micrometers to several tens of micrometers. However, making the width of the connection line L too large is undesirable because it changes the sensitivity to the frequency components of the radio waves. Specifically, if the line width is set to approximately 1% or less of the width or diameter of the patch electrode, it is possible to reduce unintended effects on the incident wave.

[0025] The sealant SE is located in the non-reflective area NRA outside the reflective area RA, and is disposed on the periphery of the area where the first substrate SUB1 and the second substrate SUB2 face each other. While the liquid crystal layer LC described above is formed by a drop injection method, it may also be formed by a liquid crystal injection method utilizing capillary action. In the latter case, a liquid crystal injection port is formed in the sealant SE, and liquid crystal material is injected through the liquid crystal injection port into the space surrounded by the first substrate SUB1, the second substrate SUB2, and the sealant SE, and the liquid crystal injection port is then sealed with a sealant.

[0026] 2 shows an example in which eight patch electrodes PE are arranged in each of the directions along the X-axis and the Y-axis. However, the number of patch electrodes PE can be varied in various ways. For example, 100 patch electrodes PE may be arranged in the direction along the X-axis, and a plurality of patch electrodes (e.g., 100) may be arranged in the direction along the Y-axis. The length of the radio wave reflector RE (first substrate SUB1) in the direction along the X-axis is, for example, 40 to 80 cm.

[0027] 3 is a plan view showing the radio wave reflector RE, and is a diagram showing the common electrode CE, transparent conductive layer TL, power supply pads pA1 and pA2, etc. In the figure, the common electrode CE and the seal material SE are each marked with a dot pattern, the transparent conductive layer TL is marked with diagonal lines slanting upward to the right, and the power supply pads pA1 and pA2 are marked with diagonal lines slanting downward to the right.

[0028] 3, the first substrate SUB1 has a power supply pad pA1 as a first power supply pad and a power supply pad pA2 as a second power supply pad. The power supply pads pA1 and pA2 are located in the non-reflective area NRA and face the second substrate SUB2. The power supply pads pA1 and pA2 are each connected to a pad p of the OLB, but may also be connected to the drive circuit DC.

[0029] The second substrate SUB2 has a base material 2, a common electrode CE, and a transparent conductive layer TL. The common electrode CE is located in the reflective area RA and extends to the non-reflective area NRA. The base material 2 is located in the reflective area RA and the non-reflective area NRA.

[0030] The transparent conductive layer TL is made of a transparent conductive material such as ITO. In this embodiment, the transparent conductive layer TL is located in the non-reflective area NRA. The transparent conductive layer TL also has an extension EX, a power receiving pad pB1 as a first power receiving pad, and a power receiving pad pB2 as a second power receiving pad.

[0031] The extension portion EX is provided with a gap from the common electrode CE in a plan view. The extension portion EX has a first extension portion EX1, a second extension portion EX2, a third extension portion EX3, and a fourth extension portion EX4. The first extension portion EX1 is located between the common electrode CE and an upper side SI1 of the substrate 2 and extends along the X-axis. The second extension portion EX2 is located between the common electrode CE and a lower side SI2 of the substrate 2 and extends along the X-axis. The third extension portion EX3 is located between the common electrode CE and a left side SI3 of the substrate 2 and is provided continuously from the first extension portion EX1 and extends along the Y-axis. The fourth extension portion EX4 is located between the common electrode CE and a right side SI4 of the substrate 2 and is provided continuously from the first extension portion EX1 and extends along the Y-axis.

[0032] The power receiving pad pB1 is located in the non-reflective area NRA and is provided continuously from each of the second extension portion EX2 and the third extension portion EX3. The power receiving pad pB1 overlaps each of the power supply pad pA1 and the protrusion portion CEa of the common electrode CE in a direction parallel to the Z axis. The protrusion portion CEa is located between the reflective area RA and the lower side SI2.

[0033] The power receiving pad pB2 is located in the non-reflective area NRA and is provided continuously from each of the second extension portion EX2 and the fourth extension portion EX4. The power receiving pad pB2 overlaps each of the power supply pad pA2 and the protrusion portion CEb of the common electrode CE in a direction parallel to the Z axis. The protrusion portion CEb is located between the reflective area RA and the bottom side SI2.

[0034] As described above, the first extending portion EX1, the second extending portion EX2, the third extending portion EX3, the fourth extending portion EX4, the power receiving pad pB1, and the power receiving pad pB2 are integrally formed to configure the transparent conductive layer TL.

[0035] In a plan view, the outer periphery OU1 of the common electrode CE is located closer to the reflective region RA than the outer periphery OU2 of the sealant SE, and the sealant SE, base material 1, base material 2, etc. protect the common electrode CE from the atmosphere (moisture), thereby suppressing corrosion of the common electrode CE.

[0036] FIG. 4 is a cross-sectional view showing the radio wave reflector RE taken along line IV-IV in FIG. 4, the first substrate SUB1 has a base material 1, an insulating layer 16, an insulating layer 17, a power supply pad pA1, an alignment film AL1, etc. The insulating layer 16 is formed above the base material 1. Note that an insulating layer, etc. (not shown) is interposed between the base material 1 and the insulating layer 16, but a description of the structure between the base material 1 and the insulating layer 16 will be omitted here.

[0037] The insulating layer 17 is formed on the insulating layer 16. The power supply pad pA1 and the alignment film AL1 are formed on the insulating layer 17. The insulating layers 16 and 17 are each formed of an inorganic insulating layer or an organic insulating layer. In this embodiment, the insulating layer 16 is an organic insulating layer and is formed of, for example, a resin. The insulating layer 17 is an inorganic insulating layer and is formed of, for example, SiN (silicon nitride).

[0038] The power receiving pad pB1 is electrically connected to the common electrode CE. The common electrode CE is in contact with the power receiving pad pB1 in the non-reflective area NRA. More specifically, the common electrode CE is in contact with the power receiving pad pB1 in an area closer to the reflective area RA than the seal material SE.

[0039] The common electrode CE has a three-layer structure (Ti-based / Al-based / Ti-based), with a lower layer made of a metal material whose main component is Ti (titanium) or a Ti-containing alloy, a middle layer made of a metal material whose main component is Al (aluminum) or an Al-containing alloy, and an upper layer made of a metal material whose main component is Ti or a Ti-containing alloy. The common electrode CE is formed by so-called TAT. The above-mentioned patch electrode PE is also formed by TAT.

[0040] The common electrode CE and the patch electrode PE may be formed of a metal other than TAT. For example, the common electrode CE and the patch electrode PE may be formed of a so-called MAM. In this case, the common electrode CE has a three-layer laminated structure (Mo-based / Al-based / Mo-based) including a lower layer made of a metal material containing Mo as a main component, such as Mo (molybdenum) or an alloy containing Mo; a middle layer made of a metal material containing Al as a main component, such as Al or an alloy containing Al; and an upper layer made of a metal material containing Mo as a main component, such as Mo or an alloy containing Mo.

[0041] In a direction parallel to the Z axis, the power receiving pad pB1 has a thickness T1, and the common electrode CE has a thickness T2. The thickness T1 is 50 to 100 nm. The thickness T2 is 800 to 1200 nm. To reduce the resistance of the common electrode CE, the common electrode CE has a large thickness T2 as described above. The side surface area of ​​the intermediate layer of the common electrode CE, which is primarily composed of Al, is roughly proportional to the thickness T2.

[0042] As the side surface area of ​​the intermediate layer increases, the concern about corrosion of the intermediate layer increases. Therefore, this embodiment provides a radio wave reflector RE in which the intermediate layer (common electrode CE) is resistant to corrosion, as described above and below.

[0043] In the non-reflective area NRA, the power receiving pad pB1 is located between the base material 2 and the common electrode CE in a direction parallel to the Z axis. In the manufacturing process of the second substrate SUB2, the power receiving pad pB1 is formed before the common electrode CE is formed. Therefore, compared to when the power receiving pad pB1 is formed after the common electrode CE is formed, corrosion of the common electrode CE can be suppressed, and in particular, corrosion of the side surfaces of the intermediate layer of the common electrode CE, which is mainly composed of Al, can be suppressed.

[0044] The radio wave reflector RE further includes a transfer TM1 as a first transfer. The transfer TM1 is located outside the sealing material SE. In other words, the sealing material SE is located between the transfer TM1 and the common electrode CE. From the viewpoint of product reliability, the transfer TM1 is positioned so as not to come into contact with the liquid crystal layer LC.

[0045] The transfer TM1 is in contact with the power supply pad pA1 and the power receiving pad pB1, so that the power supply pad pA1 can apply a voltage (common voltage) to the power receiving pad pB1 via the transfer TM1.

[0046] The power supply pad pA1 and the power receiving pad pB1 are located outside the radio wave reflector RE by the sealant SE and are exposed to the atmosphere. However, the power receiving pad pB1 is made of a transparent conductive material. The top layer of the power supply pad pA1 that contacts the transfer TM1 is made of a transparent conductive material such as ITO. Therefore, corrosion of the power supply pad pA1 and the power receiving pad pB1 can be suppressed compared to when the power receiving pad pB1 is made of Al or when the top layer of the power supply pad pA1 is made of Al.

[0047] The power supply pad pA1 may have a single-layer structure made of a transparent conductive layer, or may have a multilayer structure including a metal layer and a transparent conductive layer. The top layer of the power supply pad pA1 and the power receiving pad pB1 may be made of a material that is less susceptible to corrosion than Al. The top layer of the power supply pad pA1 and the power receiving pad pB1 are not limited to transparent conductive materials such as ITO, but may be made of any non-Al-based material, such as molybdenum (Mo) or tungsten (W).

[0048] 4 focuses on the relationship between the power supply pad pA1, the power receiving pad pB1, the transfer pad TM1, the protrusion CEa, etc., but the relationship between the power supply pad pA2, the power receiving pad pB2, the transfer TM2 as the second transfer, the protrusion CEb, etc. is similar. When focusing on the relationship between the power supply pad pA2, the power receiving pad pB2, the transfer TM2, the protrusion CEb, etc., in FIG. 4, the power supply pad pA1 can be replaced with the power supply pad pA2, the power receiving pad pB1 with the power receiving pad pB2, the transfer TM1 with the transfer TM2, and the protrusion CEa with the protrusion CEb. For example, the transfer TM2 is in contact with the power supply pad pA2 and the power receiving pad pB2.

[0049] FIG. 5 is an enlarged plan view showing the patch electrode PE shown in FIGS. 1 and 2. As shown in FIG. 5, the patch electrode PE has a square shape. The shape of the patch electrode PE is not particularly limited, but a square or a perfect circle is preferable. Focusing on the outer shape of the patch electrode PE, a shape with a length-to-width aspect ratio of 1:1 is preferable. This is because, in order to accommodate horizontally polarized waves and vertically polarized waves, it is preferable that the patch electrode PE have a rotationally symmetric structure of 90°.

[0050] The patch electrode PE has a length Px along the X-axis and a length Py along the Y-axis. It is desirable to adjust the lengths Px and Py according to the frequency band of the incident wave w1. Next, an example of a desirable relationship between the frequency band of the incident wave w1 and the lengths Px and Py will be shown. 2.4GHz: Px=Py=35mm 5.0GHz: Px=Py=16.8mm 28GHz: Px=Py=3.0mm

[0051] 6 is an enlarged cross-sectional view showing a part of the radio wave reflector RE, and shows a single reflection control part RH. In FIG. 6, the substrate 1 and the like shown in FIG. As shown in FIG. 6, the thickness d lThe cell gap is maintained by a plurality of spacers SS. In this embodiment, the spacers SS are columnar spacers that are formed on the second substrate SUB2 and protrude toward the first substrate SUB1.

[0052] The width of the spacer SS is 10 to 20 μm. While the lengths Px and Py of the patch electrode PE are on the order of mm, the width of the spacer SS is on the order of μm. Therefore, it is necessary to have multiple spacers SS in the area facing the patch electrode PE. Furthermore, the proportion of the area facing the patch electrode PE where multiple spacers SS exist is approximately 1%.

[0053] Therefore, even if the spacers SS are present in the above region, the effect of the spacers SS on the reflected wave w2 is slight. The spacers SS may be formed on the first substrate SUB1 and protrude toward the second substrate SUB2. Alternatively, the spacers SS may be spherical spacers.

[0054] The radio wave reflector RE includes a plurality of reflection control parts RH, each of which includes one of the plurality of patch electrodes PE, a portion of the common electrode CE facing the one patch electrode PE, and an area of ​​the liquid crystal layer LC facing the one patch electrode PE.

[0055] 7 is an enlarged cross-sectional view showing a part of the radio wave reflector RE, and shows a plurality of reflection control parts RH. In FIG. 7, the substrate 1, spacers SS, etc. are omitted from the illustration. 7, each reflection control unit RH functions to adjust the phase of the radio wave (incident wave w1) incident from the incident surface Sa side in accordance with the voltage applied to the patch electrode PE, and to reflect the radio wave toward the incident surface Sa to produce a reflected wave w2. In each reflection control unit RH, the reflected wave w2 is a composite wave of the radio wave reflected by the patch electrode PE and the radio wave reflected by the common electrode CE.

[0056] The patch electrodes PE are arranged at equal intervals along the X-axis. The distance (pitch) between adjacent patch electrodes PE is d kLet 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 this embodiment, the description will be given assuming that the reflected waves w2 are in phase in the first reflection direction d1. In the XZ 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 XZ plane.

[0057] In order for the radio waves reflected by the multiple reflection control parts RH to be in phase with each other in the first reflection direction d1, it is sufficient that the phases of the radio waves are aligned on a straight, two-dot chain line. For example, it is sufficient that the phase of the reflected wave w2 at point Q1b and the phase of the reflected wave w2 at point Q2a are aligned. The physical linear distance from point Q1a to point Q1b on the first patch electrode PE1 is d k × sin θ1. Therefore, when focusing on the first reflection control unit RH1 and the second reflection control unit RH2, it is sufficient to delay the phase of the reflected wave w2 from the second reflection control unit RH2 by a phase amount δ1 relative to the phase of the reflected wave w2 from the first reflection control unit RH1. Here, the phase amount δ1 is expressed by the following equation. δ1=d k ×sinθ1×2π / λ

[0058] Next, a method for driving the radio wave reflector RE will be described. Fig. 8 is a timing chart showing the change in voltage applied to the patch electrode PE for each period in the method for driving the radio wave reflector RE of this embodiment. Fig. 8 shows the first period Pd1 to the fifth period Pd5 of the driving period of the radio wave reflector RE.

[0059] 7 and 8, when the radio wave reflector RE starts to operate, during a first period Pd1, voltages V are applied to the patch electrodes PE so that the radio waves reflected by the reflection control units RH are in phase with each other in a 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 values ​​of the voltages V applied to each patch electrode PE are the same throughout the entire period Pd.

[0060] The polarity of the voltage applied to each patch electrode PE is periodically reversed relative to the potential of the common electrode CE. For example, the patch electrodes PE are driven at a driving frequency of 60 Hz. As described above, the patch electrodes PE are driven with AC current.

[0061] Even when the period Pd is changed 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 35°. Therefore, a phase difference of 245° is provided 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.

[0062] The radio wave reflector RE according to the first embodiment configured as described above includes a first substrate SUB1, a second substrate SUB2, a sealant SE, a liquid crystal layer LC, and a transfer TM1. The common electrode CE is made of metal. The common electrode CE corrodes when exposed to the atmosphere.

[0063] Therefore, the power receiving pad pB1 is electrically connected to the common electrode CE. The transfer TM1 is in contact with the power supply pad pA1 and the power receiving pad pB1. The power receiving pad pB1 is made of a transparent conductive material. The top layer of the power supply pad pA1 that is in contact with the transfer TM1 is also made of a transparent conductive material. The power supply pad pA1 and the power receiving pad pB1 are resistant to corrosion even when exposed to the atmosphere. This allows for a radio wave reflector RE with high product reliability.

[0064] The common electrode CE is made of metal and is a low-resistance material, so even if a high-resistance material such as the power receiving pad pB1 is mixed in the same electrical system as the common electrode CE, it does not adversely affect the reflection characteristics of the radio wave reflector RE.

[0065] Radio waves in the 28 GHz band used by 5G tend to travel in a very directional direction, so the communication environment deteriorates if there are obstructions (coverage holes). As a countermeasure, radio wave reflectors RE can be placed to utilize reflected waves w2. Radio wave reflectors RE can control the direction of reflected waves w2, making it possible to respond to changes in the radio wave environment.

[0066] (Modification 1 of the first embodiment) Next, Modification 1 of the first embodiment will be described. The radio wave reflector RE has the same configuration as that of the first embodiment, except for the configuration described in Modification 1. FIG. 9 is a plan view showing the radio wave reflector RE according to Modification 1, and is a diagram showing the common electrode CE, transparent conductive layer TL, power supply pads pA1 and pA2, etc. In the figure, the common electrode CE and sealing material SE are each given a dot pattern, the transparent conductive layer TL is given an upward-sloping diagonal line, and the power supply pads pA1 and pA2 are given a downward-sloping diagonal line. FIG. 10 is a cross-sectional view showing the second substrate SUB2 of the radio wave reflector RE along line XX in FIG. 9.

[0067] 9, the transparent conductive layer TL is located in the reflective area RA and the non-reflective area NRA. For example, the transparent conductive layer TL is located in the entire reflective area RA. The transparent conductive layer TL has power receiving pads pB1 and pB2.

[0068] 9 and 10, the common electrode CE is formed without protrusions CEa and CEb. The common electrode CE is in contact with the transparent conductive layer TL. However, the common electrode CE is not in contact with the power receiving pads pB1 and pB2 of the transparent conductive layer TL. The transparent conductive layer TL is located between the substrate 2 and the common electrode CE in a direction parallel to the Z axis. The transparent conductive layer TL may be formed as described above. In this first modification, the same effects as those in the first embodiment can be obtained.

[0069] (Second embodiment) Next, a second embodiment will be described. The radio wave reflector RE has the same configuration as that of the first embodiment, except for the configuration described in this embodiment. Fig. 11 is a plan view showing the radio wave reflector RE according to this embodiment. In the drawing, a dot pattern is applied to the sealing material SE.

[0070] As shown in FIG. 11, the first substrate SUB1 has, instead of the connection wiring L and wiring WL, a plurality of signal wirings SL, a plurality of control wirings GL, a plurality of switching elements SW, a drive circuit DR, and a plurality of lead wires LE.

[0071] A plurality of signal wirings SL extend along the Y-axis and are arranged in a direction along the X-axis. The signal wirings SL are connected to a drive circuit DC. A plurality of control wirings GL extend along the X-axis and are arranged in a direction along the Y-axis. The signal wirings SL and control wirings GL extend in the reflective area RA and the non-reflective area NRA. The drive circuit DR is located in the non-reflective area NRA. The plurality of control wirings GL are connected to the drive circuit DR.

[0072] The switching element SW is provided near the intersection of one signal line SL and one control line GL and is electrically connected to the one signal line SL and one control line GL. One side of the plurality of lead wires LE is connected to the drive circuit DR and the other side is connected to the pad p of the OLB. The lead wires LE may be connected to the drive circuit DC.

[0073] Fig. 12 is an enlarged cross-sectional view showing a portion of the radio wave reflector RE according to this embodiment. As shown in Fig. 12, insulating layer 11, insulating layer 12, insulating layer 13, insulating layer 14, insulating layer 15, insulating layer 16, insulating layer 17, and alignment film AL1 are formed in this order on substrate 1. Insulating layers 11 to 17 are each formed of an inorganic insulating layer or an organic insulating layer. In this embodiment, insulating layer 16 is an organic insulating layer formed of, for example, resin.

[0074] 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 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.

[0075] The control wiring GL and the 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 overlaid 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.

[0076] The conductive layer CO2 and the connection wiring layer CL1 are provided on the insulating layer 12 and the semiconductor layer SMC and are covered with the insulating layer 13. The connection wiring layer CL1 contacts the conductive layer CO1 through a contact hole formed in the insulating layer 12. The conductive layer CO2 and the connection wiring layer CL1 contact the semiconductor layer SMC and are electrically connected. One of the regions of the semiconductor layer SMC to which the conductive layer CO2 is connected and the other to which the connection wiring layer CL1 is connected is a source region, and the other is a drain region. The semiconductor layer SMC has a channel region between the source region and the drain region.

[0077] The gate electrode GE is provided on the insulating layer 13 and covered with the insulating layer 14. The gate electrode GE is electrically connected to the control line GL. The gate electrode GE overlaps at least the channel region of the semiconductor layer SMC. The control line GL, the semiconductor layer SMC, the gate electrode GE, etc. constitute a switching element SW as a TFT (thin film transistor).

[0078] The region of the control line GL that overlaps with the semiconductor layer SMC functions as a gate electrode. Therefore, the switching element SW is a dual-gate TFT. However, the switching element SW may be a bottom-gate TFT or a top-gate TFT.

[0079] The conductive layer CO3 and the connection wiring layer CL2 are provided on the insulating layer 14 and covered with the insulating layer 15. The conductive layer CO3 is in contact with the gate electrode GE through a contact hole formed in the insulating layer 14. The connection wiring layer CL2 is in contact with the connection wiring layer CL1 through a contact hole formed in the insulating layers 13 and 14.

[0080] The insulating layer 16 and the insulating layer 17 are provided in this order on the insulating layer 15. The patch electrode PE is provided on the insulating layer 17 and is covered with an alignment film AL1. The patch electrode PE passes through contact holes formed in the insulating layers 15, 16, and 17 and is in contact with the connection wiring layer CL2.

[0081] A common electrode CE and an alignment film AL2 are provided in this order on the surface of the base material 2 facing the first substrate SUB1. The control wiring GL, conductive layers CO1, CO2, CO3, connection 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 an alloy thereof. The connection wiring layers CL1, CL2 may be formed of TAT or MAM.

[0082] 11 and 12, multiple patch electrodes PE can be individually driven 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 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 in the XY plane other than the X axis and the Y axis.

[0083] The radio wave reflector RE according to the second embodiment configured as described above can achieve the same effects as those of the first embodiment. Because each patch electrode PE can be driven independently, the degree of freedom in the reflection direction d of the reflected wave w2 reflected by the radio wave reflector RE can be increased.

[0084] (Third embodiment) Next, a third embodiment will be described. In this embodiment, a phased array antenna AA will be described. The technologies relating to the common electrode CE, transparent conductive layer TL (power receiving pad pB), transfer TM, and power supply pad pA described in the above-mentioned embodiments and modifications can also be applied to the phased array antenna AA. FIG. 13 is an enlarged cross-sectional view showing a part of the phased array antenna AA according to the third embodiment. The phased array antenna AA is a device that emits radio waves from the antenna elements to the outside when a high-frequency signal reaches the antenna elements, and can change the direction of the radio waves.

[0085] 13, the phased array antenna AA includes 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 connection wires L, an insulating layer 25, a plurality of phase control electrodes AE, and an alignment film AL1.

[0086] The substrate 1 is formed in a flat plate shape and extends along an XY plane including an X-axis and a Y-axis that are orthogonal to each other. The connection wiring L is provided on the substrate 1. The insulating layer 25 is formed on the substrate 1 and the connection wiring L. The phase control electrode AE ​​is provided on the insulating layer 25. The phase control electrode AE ​​is connected to the connection wiring L through a contact hole formed in the insulating layer 25. The alignment film AL1 is formed on the insulating layer 25 and the phase control electrode AE, and covers the phase control electrode AE.

[0087] The second substrate SUB2 is disposed opposite the first substrate SUB1 with a predetermined gap therebetween. 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 phase control electrodes AE in a direction parallel to the Z axis, which is orthogonal to both the X axis and the Y axis. The alignment film AL2 covers the common electrode CE. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2. The liquid crystal layer LC faces a plurality of phase control electrodes AE on one side, and faces a common electrode CE on the other side.

[0088] Here, the thickness of the liquid crystal layer LC (cell gap) is d l In this embodiment, the thickness d l is 50 μm. However, the thickness d l is not particularly limited, and is determined by optimizing the size of the phase control electrode AE. If the phase of the high frequency signal propagating through the phase control electrode AE ​​can be sufficiently adjusted, the thickness d l Alternatively, the thickness d may be less than 50 μm. l The high frequency signal may exceed 50 μm. The high frequency signal will be described later.

[0089] 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 0 V. A voltage is also applied to the phase control electrode AE ​​via the connection wiring L. In this embodiment, the phase control electrode AE ​​is driven by AC. The liquid crystal layer LC is driven by a so-called vertical electric field. The voltage applied between the phase control electrode AE ​​and the common electrode CE acts on the liquid crystal layer LC, changing the dielectric constant of the liquid crystal layer LC.

[0090] When the dielectric constant of the liquid crystal layer LC changes, the propagation speed of the high-frequency signal in the liquid crystal layer LC also changes. Therefore, by adjusting the voltage applied to the liquid crystal layer LC, the phase of the high-frequency signal can be adjusted. Consequently, the radiation direction of the radio wave can be adjusted. In this embodiment, the absolute value of the voltage applied to the liquid crystal layer LC is 10 V or less. This is because the dielectric constant of the liquid crystal layer LC becomes saturated at 10 V. However, the absolute value of the voltage applied to the liquid crystal layer LC may exceed 10 V. The first substrate SUB1 has a radiation surface Sb that radiates radio waves on the side opposite to the side facing the second substrate SUB2.

[0091] Thickness of the liquid crystal layer LC d l The cell gap is maintained by a plurality of spacers SS. In this embodiment, the spacers SS are columnar spacers that are formed on the second substrate SUB2 and protrude toward the first substrate SUB1.

[0092] The width of the spacers SS is 10 to 20 μm. The spacers SS are not present in the region facing the phase control electrode AE. However, the spacers SS may be present in the above region. The spacers SS may be formed on the first substrate SUB1 and protrude toward the second substrate SUB2. Alternatively, the spacers SS may be spherical spacers.

[0093] The phased array antenna AA includes a plurality of phase shifters PH. Each phase shifter PH includes one of the plurality of phase control electrodes AE, a portion of the common electrode CE facing the one phase control electrode AE, and a region of the liquid crystal layer LC facing the one phase control electrode AE. Each phase shifter PH functions to adjust the phase of a high-frequency signal propagating through the phase control electrode AE ​​in accordance with a voltage applied to the phase control electrode AE.

[0094] Fig. 14 is a plan view showing the phased array antenna AA. As shown in Fig. 14, the substrates 1 and 2 are respectively located in a radiation area DA, a phase control area CA, and a non-radiation area NDA. The phase control area CA is an area adjacent to the radiation area DA. The non-radiation area NDA is an area outside the radiation area DA and the phase control area CA.

[0095] The first substrate SUB1 and the second substrate SUB2 are joined by a sealant SE disposed on the periphery of each substrate. The sealant SE surrounds at least the phase control area CA. In this embodiment, the sealant SE is located in the non-emitting area NDA and surrounds the emitting area DA and the phase control area CA. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2. The liquid crystal layer LC is provided in a space surrounded by the first substrate SUB1, the second substrate SUB2, and the sealant SE.

[0096] The plurality of phase control electrodes AE are located in a phase control area CA. The plurality of phase control electrodes AE extend in a direction along the Y axis and are arranged along the X axis. The plurality of phase control electrodes AE are electrically independent from each other. The connection wiring L extends to an area of ​​the base material 1 that does not face the second substrate SUB2.

[0097] The first substrate SUB1 includes a plurality of connection wirings L and a plurality of phase control electrodes AE, as well as a divider DI and a plurality of antenna elements AN. In this embodiment, the divider DI is a conductor that branches and extends multiple times, and is made of metal or a conductor equivalent to metal. The divider DI extends to an area of ​​the base material 1 that does not face the second substrate SUB2. The divider DI may be connected to a pad of an OLB (not shown). The divider DI is connected to an oscillator OS external to the phased array antenna AA.

[0098] The oscillator OS outputs a high-frequency signal in the microwave or millimeter-wave frequency band to the divider DI. The divider DI transmits the high-frequency signal to multiple phase control electrodes AE (multiple phase shifters PH) under the same conditions. Each phase control electrode AE ​​is placed on the divider DI with an insulating distance of several μm between them. The high-frequency signal passes between the divider DI and the phase control electrode AE ​​and is input to the phase control electrode AE.

[0099] Each antenna element AN has a patch electrode PE as an antenna and a protrusion PR. The patch electrode PE is located in a radiation area DA. In this embodiment, the protrusion PR is also located in the radiation area DA.

[0100] The plurality of patch electrodes PE are arranged at intervals along the X-axis. In other words, the plurality of patch electrodes PE are arranged one-dimensionally. When the plurality of patch electrodes PE are arranged one-dimensionally, driving of the plurality of patch electrodes PE can improve the phase directivity.

[0101] In this embodiment, the multiple patch electrodes PE are arranged at equal intervals in the direction along the X-axis. In the XY plane, the multiple patch electrodes PE have the same shape and the same size. In this embodiment, the patch electrode PE has a square shape. The patch electrode PE has a length of several millimeters in the direction along the X-axis and the direction along the Y-axis. However, the size of the patch electrode PE (the above length) is not particularly limited. Furthermore, the shape of the patch electrode PE is not particularly limited, and may be a circle such as a perfect circle, a rectangle other than a square, or the like.

[0102] The multiple patch electrodes PE include a first patch electrode PE1 to an eighth patch electrode PE8. For example, in the direction along the X-axis, the second patch electrode PE2 (second antenna) is located between the first patch electrode PE1 (first antenna) and the third patch electrode PE3 (third antenna).

[0103] 14 shows an example in which eight patch electrodes PE are arranged in the direction along the X-axis. However, the number of patch electrodes PE can be varied in various ways. For example, 100 patch electrodes PE may be arranged in the direction along the X-axis. Although a detailed description will be omitted, the multiple patch electrodes PE may be arranged in a matrix in the direction along the X-axis and the direction along the Y-axis. Even in this case, the multiple patch electrodes PE (antennas) correspond one-to-one to the multiple phase control electrodes AE.

[0104] Each patch electrode PE (antenna) emits radio waves based on a high-frequency signal transmitted from the corresponding phase control electrode AE. The protrusions PR are connected to the patch electrode PE. In this embodiment, the protrusions PR are formed integrally with the patch electrode PE. The protrusions PR protrude from the patch electrode PE toward the corresponding phase control electrode AE. The protrusions PR have a rectangular shape. Each protrusion PR (antenna element AN) is arranged on the phase control electrode AE ​​at an insulating distance of several μm. The multiple protrusions PR on the first substrate SUB1 include, for example, a first protrusion PR1 connected to a first patch electrode PE1.

[0105] There are no particular limitations on the gap between the phase control electrode AE ​​and the antenna element AN, and on the shapes of both elements sandwiching the gap. However, the shapes of the phase control electrode AE ​​and the antenna element AN should be determined so that the output impedance on the phase control electrode AE ​​side matches the input impedance on the antenna element AN side, preventing reflection of high-frequency signals between the phase control electrode AE ​​and the antenna element AN. For example, the antenna element AN may be formed without a protrusion PR.

[0106] Each phase control electrode AE ​​has a function of adjusting the phase of a radio frequency signal input from the distributor DI and transmitting the phase-adjusted radio frequency signal to a corresponding one of the plurality of patch electrodes PE (plurality of antennas). The plurality of phase control electrodes AE include first phase control electrodes AE1 to eighth phase control electrodes AE8 corresponding to the first patch electrode PE1 to eighth patch electrode PE8. For example, the first phase control electrode AE1 transmits a radio frequency signal to the first patch electrode PE1, the second phase control electrode AE2 transmits a radio frequency signal to the second patch electrode PE2, and the third phase control electrode AE3 transmits a radio frequency signal to the third patch electrode PE3.

[0107] For example, the gap between the first phase control electrode AE1 and the first protrusion PR1 is several μm, whereas the gap between the first phase control electrode AE1 and the second phase control electrode AE2 is several mm. Therefore, a high-frequency signal input to the first phase control electrode AE1 passes between the first phase control electrode AE1 and the first protrusion PR1 and is input to the first protrusion PR1, but does not leak to the second phase control electrode AE2.

[0108] Here, the size of the phase shifter PH (phase control electrode AE) will be described. In the XY plane, the multiple phase control electrodes AE have the same shape and the same size. In this embodiment, the phase control electrode AE ​​has a rectangular shape with its major axis along the Y axis. The phase control electrode AE ​​has a width WI in the direction along the X axis and a length LN in the direction along the Y axis. In this embodiment, WI = 100 μm and LN = 60 mm.

[0109] When the dielectric constant of the liquid crystal layer LC changes from e1 to e2 by applying a bias voltage to the liquid crystal layer LC, the phase change amount of the high frequency signal is (e2 0.5 -e1 0.5 )·LN / λ. In this embodiment, the phase shift can be controlled from 0 to 360° by the bias voltage applied to the liquid crystal layer LC. The phase shifter PH shifts the phase of the high-frequency signal by a maximum of 360°. Therefore, if the size of the phase control electrode AE ​​in the XY plane is halved to 100 μm × 30 mm, the phase shifter PH shifts the phase of the high-frequency signal by a maximum of 180°.

[0110] In a phased array antenna AA, the direction of the radiated radio waves (high frequency waves) is changed by creating a difference in the amount of phase change between adjacent phase shifters PH, but since the bias voltage to the liquid crystal layer LC is changed over time, it is necessary to fully utilize the phase change amount up to 360°. The size of the phase shifter PH (phase control electrode AE) is determined from the above considerations.

[0111] From the above, the phased array antenna AA is configured so that a phase difference of up to 360° can be imparted between the high-frequency signal transmitted by one phase shifter PH to the patch electrode PE and the high-frequency signal transmitted by another phase shifter PH to the patch electrode PE. Therefore, the phased array antenna AA is configured so that a phase difference of up to 360° can be imparted between the radio waves radiated from one patch electrode PE and the radio waves radiated from another patch electrode PE.

[0112] The connection wiring L, the phase control electrode AE, the patch electrode PE, the protrusion PR, and the common electrode CE are formed of a metal or a conductor equivalent to a metal. The liquid crystal layer LC may be provided in at least an area facing all of the phase control electrodes AE. In this embodiment, the sealing material SE is disposed on the periphery of each of the first substrate SUB1 and the second substrate SUB2 as described above. Therefore, the liquid crystal layer LC may face the plurality of antenna elements AN, the distributor DI, and the plurality of connection wirings L. The common electrode CE is located at least in the phase control area CA. The common electrode CE faces the plurality of phase control electrodes AE in a direction parallel to the Z axis.

[0113] The connecting wire L is a thin wire having a width of several micrometers, and the area of ​​the connecting wire L in the XY plane is sufficiently smaller than the area of ​​the phase control electrode AE, which makes it difficult for the connecting wire L to function as a phase shifter PH. In addition, when the phased array antenna AA radiates radio waves in any radiation direction, the phase amount of the high-frequency signal adjusted (delayed) by the phase shifter PH can be inferred from the description above using Figure 7, and a detailed explanation thereof will be omitted.

[0114] 15 is a plan view showing the phased array antenna AA, and is a diagram showing the common electrode CE, transparent conductive layer TL, power supply pads pA1 and pA2, etc. In the figure, the common electrode CE and the seal material SE are each marked with a dot pattern, the transparent conductive layer TL is marked with diagonal lines slanting upward to the right, and the power supply pads pA1 and pA2 are marked with diagonal lines slanting downward to the right.

[0115] 15, the first substrate SUB1 has power supply pads pA1 and pA2. The power supply pads pA1 and pA2 are located in the non-radiative area NDA and face the second substrate SUB2. The power supply pads pA1 and pA2 are each connected to a pad p of the OLB.

[0116] The second substrate SUB2 has a base material 2, a common electrode CE, and a transparent conductive layer TL. The common electrode CE needs to be located at least in the phase control region CA. In this embodiment, the common electrode CE faces all of the phase control electrodes AE, but also faces the antenna elements AN, the distributor DI, and the connection wiring L. Therefore, the common electrode CE is located in the emission region DA, the phase control region CA, and the non-emission region NDA. However, the common electrode CE does not need to face the antenna elements AN, the distributor DI, and the connection wiring L.

[0117] The transparent conductive layer TL is made of a transparent conductive material such as ITO. In this embodiment, the transparent conductive layer TL is located in the non-radiative area NDA. The transparent conductive layer TL also has an extension EX, a power receiving pad pB1 as a first power receiving pad, and a power receiving pad pB2 as a second power receiving pad.

[0118] The extension portion EX is provided with a gap from the common electrode CE in a plan view. The extension portion EX has a first extension portion EX1, a second extension portion EX2, a third extension portion EX3, and a fourth extension portion EX4. The first extension portion EX1 is located between the common electrode CE and an upper side SI1 of the substrate 2 and extends along the X-axis. The second extension portion EX2 is located between the common electrode CE and a lower side SI2 of the substrate 2 and extends along the X-axis. The third extension portion EX3 is located between the common electrode CE and a left side SI3 of the substrate 2 and is provided continuously from the first extension portion EX1 and extends along the Y-axis. The fourth extension portion EX4 is located between the common electrode CE and a right side SI4 of the substrate 2 and is provided continuously from the first extension portion EX1 and extends along the Y-axis.

[0119] The power receiving pad pB1 is located in the non-radiating area NDA and is provided continuously from each of the second extension portion EX2 and the third extension portion EX3. The power receiving pad pB1 overlaps each of the power supply pad pA1 and the protrusion portion CEa of the common electrode CE in a direction parallel to the Z axis. The protrusion portion CEa is located between the phase control area CA and the lower side SI2.

[0120] The power receiving pad pB2 is located in the non-radiating area NDA and is provided continuously from each of the second extension portion EX2 and the fourth extension portion EX4. The power receiving pad pB2 overlaps each of the power supply pad pA2 and the protrusion portion CEb of the common electrode CE in a direction parallel to the Z axis. The protrusion portion CEb is located between the phase control area CA and the lower side SI2.

[0121] As described above, the first extending portion EX1, the second extending portion EX2, the third extending portion EX3, the fourth extending portion EX4, the power receiving pad pB1, and the power receiving pad pB2 are integrally formed to configure the transparent conductive layer TL.

[0122] In a plan view, the outer periphery OU1 of the common electrode CE is located closer to the phase control region CA than the outer periphery OU2 of the sealant SE, and the sealant SE, base material 1, base material 2, etc. protect the common electrode CE from the atmosphere (moisture), thereby suppressing corrosion of the common electrode CE.

[0123] FIG. 16 is a cross-sectional view showing the phased array antenna AA along line XVI-XVI in FIG. 16, the first substrate SUB1 has a base material 1, an insulating layer 24, an insulating layer 25, a power supply pad pA1, an alignment film AL1, etc. The insulating layer 24 is formed above the base material 1. Note that an insulating layer (not shown) may be interposed between the base material 1 and the insulating layer 24.

[0124] The insulating layer 25 is formed on the insulating layer 16. The power supply pad pA1 and the alignment film AL1 are formed on the insulating layer 25. The insulating layers 24 and 25 are each formed of an inorganic insulating layer or an organic insulating layer.

[0125] The power receiving pad pB1 is electrically connected to the common electrode CE. The common electrode CE is in contact with the power receiving pad pB1 in the non-reflective area NRA. More specifically, the common electrode CE is in contact with the power receiving pad pB1 in an area closer to the phase control area CA than the seal material SE. The common electrode CE is formed of a metal such as TAT ​​or MAM.

[0126] In the direction parallel to the Z axis, the thickness of the power receiving pad pB1 is the same as the thickness T1 shown in Fig. 4, and the thickness of the common electrode CE is the same as the thickness T2 shown in Fig. 4. Also, this embodiment provides a phased array antenna AA in which the common electrode CE is resistant to corrosion.

[0127] In the non-reflective area NRA, the power receiving pad pB1 is located between the base material 2 and the common electrode CE in a direction parallel to the Z axis. In the manufacturing process of the second substrate SUB2, the power receiving pad pB1 is formed before the common electrode CE is formed. This makes it possible to suppress corrosion of the common electrode CE.

[0128] The phased array antenna AA further includes a transfer TM1. The transfer TM1 is located outside the sealant SE. In other words, the sealant SE is located between the transfer TM1 and the common electrode CE. From the viewpoint of product reliability, the transfer TM1 is arranged so as not to come into contact with the liquid crystal layer LC.

[0129] The transfer TM1 is in contact with the power supply pad pA1 and the power receiving pad pB1, so that the power supply pad pA1 can apply a voltage (common voltage) to the power receiving pad pB1 via the transfer TM1.

[0130] The power receiving pad pB1 is made of a transparent conductive material. The top layer of the power supply pad pA1 that contacts the transfer TM1 is also made of a transparent conductive material. This can prevent corrosion of the power supply pad pA1 and the power receiving pad pB1.

[0131] The power supply pad pA1 may have a single-layer structure made of a transparent conductive layer, or may have a multilayer structure including a metal layer and a transparent conductive layer. The top layer of the power supply pad pA1 and the power reception pad pB1 may be made of a material that is less susceptible to corrosion than Al.

[0132] In Figure 16, we have focused on the relationship between the power supply pad pA1, the power receiving pad pB1, the transfer TM1, the protrusion CEa, etc., but the relationship between the power supply pad pA2, the power receiving pad pB2, the transfer TM2 as the second transfer, the protrusion CEb, etc. is similar.

[0133] The phased array antenna AA according to the third embodiment configured as described above includes a first substrate SUB1, a second substrate SUB2, a sealant SE, a liquid crystal layer LC, and a transfer TM1. The power receiving pad pB1 is made of a transparent conductive material. The top layer of the power supply pad pA1 that contacts the transfer TM1 is also made of a transparent conductive material. The power supply pad pA1 and the power receiving pad pB1 are resistant to corrosion. This allows for a phased array antenna AA with high product reliability.

[0134] The common electrode CE is made of metal and has low resistance, so even if a high-resistance material such as the power receiving pad pB1 is present in the same electrical system as the common electrode CE, it does not adversely affect the radio wave radiation characteristics of the phased array antenna AA.

[0135] (Modification 1 of the third embodiment) Next, a first modification of the third embodiment will be described. The phased array antenna AA has the same configuration as that of the third embodiment, except for the configuration described in this first modification.

[0136] Fig. 17 is a plan view showing the phased array antenna AA according to Modification 1, illustrating the common electrode CE, transparent conductive layer TL, power supply pads pA1 and pA2, etc. In the figure, the common electrode CE and sealant SE are each marked with a dot pattern, the transparent conductive layer TL is marked with diagonal lines slanting upward to the right, and the power supply pads pA1 and pA2 are marked with diagonal lines slanting downward to the right. Fig. 18 is a cross-sectional view showing the second substrate SUB2 of the phased array antenna AA along line XVIII-XVIII in Fig. 17.

[0137] 17, the transparent conductive layer TL is located in the emitting region DA, the phase control region CA, and the non-emitting region NDA. For example, the transparent conductive layer TL is located throughout the phase control region CA. The transparent conductive layer TL has power receiving pads pB1 and pB2.

[0138] 17 and 18, the common electrode CE is formed without protrusions CEa and CEb. The common electrode CE is in contact with the transparent conductive layer TL. However, the common electrode CE is not in contact with the power receiving pads pB1 and pB2 of the transparent conductive layer TL. The transparent conductive layer TL is located between the substrate 2 and the common electrode CE in a direction parallel to the Z axis. The transparent conductive layer TL may be formed as described above. In this first modification, the same effects as those of the third embodiment can be obtained.

[0139] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0140] For example, the second substrate SUB2 may include the power receiving pads pB1 and pB2 of the transparent conductive layer TL, and therefore may include the extensions EX as necessary.

Claims

1. a first substrate having a plurality of patch electrodes located in a first region and arranged in a matrix at intervals along X-axis and Y-axis perpendicular to each other, and a first power supply pad located in a second region outside the first region; a second substrate including: a common electrode located in the first region and facing the plurality of patch electrodes in a direction parallel to a Z-axis that is orthogonal to each of the X-axis and the Y-axis; and a first power receiving pad located in the second region and electrically connected to the common electrode and overlapping the first power supply pad in a direction parallel to the Z-axis; a sealant located in the second region and joining the first substrate and the second substrate; a liquid crystal layer held between the first substrate and the second substrate and surrounded by the sealing material; a first transfer in contact with the first power supply pad and the first power receiving pad; a top layer of the first power supply pad that contacts the first transfer is made of a transparent conductive material; the first power receiving pad is made of a transparent conductive material; The common electrode is made of metal.

2. The radio wave reflector according to claim 1 , wherein, in a plan view, an outer periphery of the common electrode is located closer to the first region than an outer periphery of the sealing material.

3. the second substrate further includes an electrically insulating base material located in the first region and the second region, the common electrode extends to the second region and contacts the first power receiving pad in the second region; The radio wave reflector according to claim 1 , wherein in the second region, the first power receiving pad is located between the base material and the common electrode in a direction parallel to the Z axis.

4. the second substrate further includes a transparent conductive layer located in the second region and formed of a transparent conductive material; 2. The radio wave reflector according to claim 1, wherein the transparent conductive layer has an extension portion that is provided with a gap from the common electrode in a planar view, and the first power receiving pad that is superimposed on the common electrode in a planar view and formed integrally with the extension portion.

5. the second substrate further includes an electrically insulating base material located in the first region and the second region, and a transparent conductive layer located in the first region and the second region and formed of a transparent conductive material, the common electrode is in contact with the transparent conductive layer; The radio wave reflector according to claim 1 , wherein the transparent conductive layer has the first power receiving pad and is located between the substrate and the common electrode in a direction parallel to the Z axis.

6. Further comprising a second transfer; the first substrate further includes a second power supply pad located in the second region; the second substrate further includes a second power receiving pad located in the second region, electrically connected to the common electrode, and overlapping the second power supply pad in a direction parallel to the Z axis; the second transfer contacts the second power supply pad and the second power receiving pad; a top layer of the second power supply pad that contacts the second transfer is made of a transparent conductive material; The radio wave reflector according to claim 1 , wherein the second power receiving pad is made of a transparent conductive material.

7. each reflection control section has one patch electrode among the plurality of patch electrodes, a portion of the common electrode facing the one patch electrode, and a region of the liquid crystal layer facing the one patch electrode; the first substrate has an incident surface on a side opposite to a side facing the second substrate, 2. The radio wave reflector according to claim 1, wherein each of the reflection control sections adjusts the phase of the radio wave incident from the incident surface side in accordance with the voltage applied to the patch electrode, and reflects the radio wave toward the incident surface side.

8. a first substrate having a plurality of antennas located in a radiation region and spaced apart along an X-axis, a plurality of electrically independent phase control electrodes located in a phase control region adjacent to the radiation region, and a first power supply pad located in a non-radiative region outside the radiation region and the phase control region; a second substrate including: a common electrode located in the phase control region and facing the plurality of phase control electrodes in a direction parallel to a Z-axis perpendicular to the X-axis; and a first power receiving pad located in the non-radiative region and electrically connected to the common electrode and overlapping the first power supply pad in a direction parallel to the Z-axis; a sealing material surrounding the phase control region and joining the first substrate and the second substrate; a liquid crystal layer held between the first substrate and the second substrate and surrounded by the sealing material; a first transfer in contact with the first power supply pad and the first power receiving pad; a top layer of the first power supply pad that contacts the first transfer is made of a transparent conductive material; the first power receiving pad is made of a transparent conductive material; The phased array antenna, wherein the common electrode is made of metal.

9. 9. The phased array antenna according to claim 8, wherein, in a plan view, an outer periphery of the common electrode is located closer to the phase control region than an outer periphery of the sealing material.

10. the second substrate further includes an electrically insulating base material positioned in the emitting region, the phase control region, and the non-emitting region; the common electrode extends to the non-radiative region and contacts the first power receiving pad in the non-radiative region; The phased array antenna according to claim 8 , wherein in the non-radiating region, the first power receiving pad is located between the substrate and the common electrode in a direction parallel to the Z-axis.

11. the second substrate further includes a transparent conductive layer located in the non-emitting region and made of a transparent conductive material; 9. The phased array antenna according to claim 8, wherein the transparent conductive layer has an extension portion provided on the common electrode with a gap therebetween in a plan view, and the first power receiving pad overlapping the common electrode in a plan view and formed integrally with the extension portion.

12. the second substrate further includes an electrically insulating base material located in the emitting region, the phase control region, and the non-emitting region, and a transparent conductive layer located in the phase control region and the non-emitting region and formed of a transparent conductive material, the common electrode is in contact with the transparent conductive layer; The phased array antenna according to claim 8 , wherein the transparent conductive layer has the first power receiving pad and is located between the substrate and the common electrode in a direction parallel to the Z axis.

13. Further comprising a second transfer; the first substrate further includes a second power supply pad located in the non-radiative area; the second substrate further includes a second power receiving pad located in the non-radiative region, electrically connected to the common electrode, and overlapping the second power supply pad in a direction parallel to the Z axis; the second transfer contacts the second power supply pad and the second power receiving pad; a top layer of the second power supply pad that contacts the second transfer is made of a transparent conductive material; The phased array antenna according to claim 8 , wherein the second power receiving pad is formed of a transparent conductive material.

14. each phase shifter has one phase control electrode of the plurality of phase control electrodes, a portion of the common electrode facing the one phase control electrode, and a region of the liquid crystal layer facing the one phase control electrode; each of the phase control electrodes transmits an input high frequency signal to a corresponding one of the plurality of antennas; the phase shifter adjusts the phase of the high-frequency signal in accordance with a voltage applied to the phase control electrode; The phased array antenna according to claim 8 , wherein each of the antennas radiates a radio wave based on the high-frequency signal.

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