Radio wave reflecting element, radio wave reflecting device equipped with radio wave reflecting element, and antenna

Abstract

The electromagnetic wave reflecting element includes a patch electrode, an insulating film, an auxiliary electrode, a liquid crystal layer, and a counter electrode. The insulating film is located on the patch electrode. The auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the patch electrode. The liquid crystal layer is located on the auxiliary electrode, and the counter electrode is located on the liquid crystal layer. The patch electrode and the auxiliary electrode are configured to be individually subjected to variable potentials.

Description

Technical Field

[0001] One embodiment of the present invention relates to an electromagnetic wave reflecting element utilizing a liquid crystal, an electromagnetic wave reflecting device having the electromagnetic wave reflecting element, and a driving method thereof. Alternatively, one embodiment of the present invention relates to a phase shifter utilizing a liquid crystal, an antenna having the phase shifter, a phased array antenna equipped with the antenna, and a driving method thereof. Background Technology

[0002] Liquid crystal molecules exhibit anisotropic dielectric constants. Therefore, by adjusting the electric field applied to the liquid crystal layer containing the liquid crystal molecules, the orientation of the liquid crystal molecules can be controlled, thereby controlling the dielectric constant of the liquid crystal layer. By utilizing this characteristic, it is possible to realize radio wave reflectors that can control the reflection angle of incident radio waves, and phased array antennas that can transmit directional radio waves in a selected direction (see, for example, Patent Documents 1 to 3).

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 11-103201 Patent Document 2: Japanese Patent Application Publication No. 2019-530387 Patent Document 3: Japanese Patent Application Publication No. 2022-25914 Summary of the Invention

[0004] The problem that the invention aims to solve One objective of one embodiment of the present invention is to provide an electromagnetic wave reflecting device having a liquid crystal layer and capable of rapidly switching electromagnetic wave reflection characteristics, and a driving method thereof. Alternatively, one objective of one embodiment of the present invention is to provide a phased array antenna having a liquid crystal layer and capable of rapidly switching the transmission direction of electromagnetic waves, and a driving method thereof.

[0005] Methods for solving problems One embodiment of the present invention is an electromagnetic wave reflecting element. The electromagnetic wave reflecting element includes a patch electrode, an insulating film, an auxiliary electrode, a liquid crystal layer, and a counter electrode. The insulating film is located on the patch electrode. The auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the patch electrode. The liquid crystal layer is located on the auxiliary electrode, and the counter electrode is located on the liquid crystal layer. The patch electrode and the auxiliary electrode are configured to be individually subjected to variable potentials.

[0006] One embodiment of the present invention is an electromagnetic wave reflecting device. This electromagnetic wave reflecting device includes a plurality of electromagnetic wave reflecting elements configured in a matrix shape having multiple rows and multiple columns. Each of the plurality of electromagnetic wave reflecting elements includes a patch electrode, an insulating film, an auxiliary electrode, a liquid crystal layer, and a counter electrode. The insulating film is located on the patch electrode. The auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the patch electrode. The liquid crystal layer is located on the auxiliary electrode. The counter electrode is located on the liquid crystal layer and is shared by the plurality of electromagnetic wave reflecting elements. The patch electrode and the auxiliary electrode are configured to be individually applied with variable potentials.

[0007] One embodiment of the present invention is an antenna. The antenna includes antenna electrodes and a phase shifter. The phase shifter has a microstrip line, an insulating film, an auxiliary electrode, a liquid crystal layer, and a counter electrode. The microstrip line and the antenna electrodes exist in the same layer. The insulating film is located on the microstrip line. The auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the microstrip line. The liquid crystal layer is located on the auxiliary electrode, and the counter electrode is located on the liquid crystal layer. The antenna electrodes are electrically insulated from the microstrip line through the insulating film.

[0008] One embodiment of the present invention is a phased array antenna. The phased array antenna has multiple antennas. Each antenna has an antenna electrode and a phase shifter. The phase shifter has a microstrip line, an insulating film, an auxiliary electrode, a liquid crystal layer, and a counter electrode. The microstrip line and the antenna electrode exist in the same layer. The insulating film is located on the microstrip line. The auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the microstrip line. The liquid crystal layer is located on the auxiliary electrode, and the counter electrode is located on the liquid crystal layer. The antenna electrode is electrically insulated from the microstrip line through the insulating film. Attached Figure Description

[0009] [ Figure 1 [Image 1] is a schematic top view of an electromagnetic wave reflecting device according to one embodiment of the present invention.

[0010] [ Figure 2 [Image 1] is a schematic top view of an electromagnetic wave reflecting element according to one embodiment of the present invention.

[0011] [ Figure 3 [Illustrated end view of an electromagnetic wave reflecting element according to one embodiment of the present invention.]

[0012] [ Figure 4 [Illustrated end view of an electromagnetic wave reflecting element according to one embodiment of the present invention.]

[0013] [ Figure 5 [Image 1] is a schematic top view of an electromagnetic wave reflecting element according to one embodiment of the present invention.

[0014] [ Figure 6[This is an example of a timing diagram of an electromagnetic wave reflection device according to an embodiment of the present invention.]

[0015] [ Figure 7 [ ] is a schematic end view illustrating a driving method for an electromagnetic wave reflection device according to an embodiment of the present invention.

[0016] [ Figure 8 [ ] is a schematic end view illustrating a driving method for an electromagnetic wave reflection device according to an embodiment of the present invention.

[0017] [ Figure 9 [ ] is a schematic end view illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention.

[0018] [ Figure 10 [Image 1] is a schematic diagram illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention.

[0019] [ Figure 11 [Image 1] is a schematic diagram illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention.

[0020] [ Figure 12 [Image 1] is a schematic diagram illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention.

[0021] [ Figure 13 [Image 1] is a schematic top view of an electromagnetic wave reflecting element according to one embodiment of the present invention.

[0022] [ Figure 14 [Image 1] is a schematic top view of a phased array antenna according to one embodiment of the present invention.

[0023] [ Figure 15 [Illustrated top view of an antenna according to one embodiment of the present invention]

[0024] [ Figure 16 [Illustrated end view of an antenna according to one embodiment of the present invention]

[0025] [ Figure 17 [Illustrated end view of an antenna according to one embodiment of the present invention]

[0026] [ Figure 18 [Illustrated end view of an antenna according to one embodiment of the present invention]

[0027] [ Figure 19 [This is an example of a timing diagram of an antenna according to an embodiment of the present invention.]

[0028] [ Figure 20[Image 1] is a schematic diagram illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention.

[0029] [ Figure 21 [Image 1] is a schematic diagram illustrating a driving method for an electromagnetic wave reflection device according to one embodiment of the present invention. Detailed Implementation

[0030] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings and the like. However, the present invention can be implemented in various ways without departing from its spirit and is not to be interpreted as limited to the description of the embodiments illustrated below.

[0031] With regard to the accompanying drawings, to make the explanation clearer, the width, thickness, shape, etc. of each part are sometimes schematically shown compared to the actual form, but this is merely an example and does not limit the interpretation of the invention. In this specification and the drawings, elements having the same function as those described with respect to previously shown figures are sometimes labeled with the same reference numerals and repeated descriptions are omitted. When multiple identical or similar configurations are generally represented, the reference numerals are used; when these multiple configurations are represented individually, hyphens and natural numbers are used after the reference numerals. Additionally, when representing a part of a configuration, lowercase letters are used after the reference numerals.

[0032] In this specification and claims, when expressing the manner of configuring other structures on top of a certain structure, the phrase "on top of" includes, unless otherwise specified, two situations: configuring other structures directly above a certain structure in connection with it, and configuring other structures above a certain structure with another structure in between.

[0033] In this specification and claims, the expression "a structure is exposed from other structures" refers to a situation where a portion of a structure is not covered by other structures, and also includes a situation where the portion not covered by other structures is further covered by another structure. Furthermore, this expression also includes a situation where a structure is not connected to other structures.

[0034] In this invention, when multiple membranes are formed by processing a single membrane, these multiple membranes sometimes have different functions and roles. However, these multiple membranes originate from membranes formed as the same layer in the same process, and have substantially the same layer structure, the same material, and the same morphology. Therefore, these multiple membranes are defined as membranes existing in the same layer.

[0035] In this specification and claims, the expression "orthogonal" for two structures includes not only the state where the two structures intersect perpendicularly (90°), but also the state where they intersect at an angle of 90° ± 10°. Similarly, the expression "parallel" for two structures includes not only the case where the angle between the extension directions of the two structures is 0°, but also the case where the angle is 0° ± 10°.

[0036] <First Implementation> The following describes an embodiment of the present invention, including an electromagnetic wave reflecting element, an electromagnetic wave reflecting device comprising the same, and a method for driving the electromagnetic wave reflecting device.

[0037] 1. Radio wave reflection device (1) Overall structure of the radio wave reflection device One embodiment of the present invention provides an electromagnetic wave reflecting device, a so-called liquid crystal metasurface reflector, which utilizes the change in dielectric constant resulting from an orientation change in the liquid crystal layer induced by an electric field, thereby exhibiting the function of reflecting incident electromagnetic waves in a chosen direction. There is no limitation on the frequency of the wavelengths that can be reflected, for example, in the range of 400 MHz to 50 GHz. This electromagnetic wave reflecting device can be used for the reflection of typical electromagnetic waves in the 400 MHz to 6.0 GHz band, the 2.5 GHz to 4.7 GHz band, and the 24 GHz to 50 GHz band.

[0038] Figure 1 The diagram shows a schematic top view of an electromagnetic wave reflecting device 100. The electromagnetic wave reflecting device 100 includes a substrate 102 and... Figure 1 The opposing substrates (not shown) have patterned insulating films, semiconductor films, conductive films, liquid crystal layers, etc., disposed between them. By appropriately stacking these films, multiple electromagnetic wave reflecting elements 120 arranged in a matrix shape with multiple rows and columns can be formed. In addition to the electromagnetic wave reflecting elements 120, the electromagnetic wave reflecting device 100 also includes a scan line driving circuit 106 for supplying scan signals to the electromagnetic wave reflecting elements 120, and a signal line driving circuit 108 for supplying control signals. The scan line driving circuit 106 and the signal line driving circuit 108 can be formed from insulating films, semiconductor films, or conductive films formed on the substrate 102, or they can be formed by mounting an integrated circuit formed on a semiconductor substrate on the substrate 102. The number of scan line driving circuits 106 and signal line driving circuits 108 can be one or more. For example, as shown... Figure 1 As shown, two scan line drive circuits 106 can be disposed on the substrate 102 in such a way that multiple radio wave reflecting elements 120 are sandwiched between them. The signal line drive circuit 108 is disposed on one side of the substrate 102.

[0039] Figure 1Although not shown in the diagram, multiple scan lines (hereinafter referred to as gate lines) and multiple signal lines extend from the scan line driving circuit 106 and the signal line driving circuit 108, respectively, and are electrically connected to the electromagnetic wave reflecting element 120. Therefore, the electromagnetic wave reflecting element 120 is electrically connected to the corresponding gate lines and signal lines. Multiple terminals 110 are also provided on the substrate 102, through which external circuitry (not shown) supplies various signals for driving the electromagnetic wave reflecting element 120. The scan line driving circuit 106 and the signal line driving circuit 108 generate scan signals and control signals respectively based on the supplied signals and supply them to the electromagnetic wave reflecting element 120.

[0040] (2) Structure of electromagnetic wave reflecting element Figure 2 The diagram shows a schematic top view of an electromagnetic wave reflecting element 120. Figure 3 and Figure 4 The text shows the directions along the lines. Figure 2 A schematic diagram of the end face obtained by the dotted lines AA' and BB'. Figure 2 The diagram shows a portion of the configuration of the radio wave reflecting elements 120 adjacent in the column direction (second gate line 116-2 and first gate line 116-1).

[0041] like Figure 2 As shown, the radio wave reflecting device 100 has two gate lines (first gate line 116-1 and second gate line 116-2) for supplying scanning signals to a plurality of radio wave reflecting elements 120 arranged in each of a plurality of rows, and a signal line 118 for supplying control signals to a plurality of radio wave reflecting elements 120 arranged in each of a plurality of columns. The first gate line 116-1 and the second gate line 116-2 extend in the row direction, and the signal line 118 extends in the column direction. That is, the signal line 118 intersects with the first gate line 116-1 and the second gate line 116-2.

[0042] Each electromagnetic wave reflecting element 120 includes at least two transistors (a first transistor 140 and a second transistor 150), and a portion of each of the first gate line 116-1 and the second gate line 116-2 constitutes the gate electrode of the first transistor 140 and the second transistor 150, respectively. In other words, the first transistor 140 and the second transistor 150 are connected to different gate lines, namely the first gate line 116-1 and the second gate line 116-2. Therefore, the first gate line 116-1 is electrically connected to the gate electrode of the first transistor 140 disposed in the row of electromagnetic wave reflecting elements 120 arranged therein. On the other hand, the second gate line 116-2 is electrically connected to the gate electrode of the second transistor 150 disposed in the row of electromagnetic wave reflecting elements 120 arranged therein. The scan line driving circuit 106 supplies potential to the first gate line 116-1 and the second gate line 116-2 individually. Therefore, in each of the radio wave reflecting elements 120, the first transistor 140 and the second transistor 150 can be driven and controlled independently.

[0043] Regarding signal line 118, in each row, a portion of it functions as terminal 146 of the first transistor 140, and another portion functions as terminal 156 of the second transistor 150 (see [link]). Figure 3 , Figure 4 Therefore, when considering a radio wave reflecting element 120, the signal line 118 is electrically connected to the first transistor 140 and the second transistor 150 of the radio wave reflecting element 120, and is also electrically connected to the first transistor 140 and the second transistor 150 in each of the radio wave reflecting elements 120 in the same row as the radio wave reflecting element 120.

[0044] Therefore, the number of gate lines 116 is twice that of a conventional liquid crystal display device. However, the number of radio wave reflecting elements provided in a radio wave reflecting device is generally much smaller than the number of pixels provided in a liquid crystal display device, thus reducing the load on the scan line driving circuit 106. Therefore, the scan line driving circuit 106 can be used to switch all the radio wave reflecting elements 120 on and off at high speed.

[0045] like Figure 3 and Figure 4 As shown, the first transistor 140 and the second transistor 150 are disposed on the substrate 102 directly or via an undercoating 122, which is an optional configuration. Figure 2 and Figure 3In the example shown, the first transistor 140 is composed of a gate electrode 142, a gate insulating film 124 on the gate electrode 142, a semiconductor film 144 located on the gate insulating film 124 and overlapping the gate electrode 142, and terminals 146 and 148 electrically connected to the semiconductor film 144. Similarly, the second transistor 150 is composed of a gate electrode 152, a gate insulating film 124 on the gate electrode 152, a semiconductor film 154 located on the gate insulating film 124 and overlapping the gate electrode 152, and terminals 156 and 158 electrically connected to the semiconductor film 154. Figures 2 to 4 In the example shown, both transistor 140 and transistor 150 have a bottom-gate structure, but there are no restrictions on their structure. Transistor 140 and transistor 150 can also have a top-gate structure, or they can have gate electrodes above and below the semiconductor film. There are also no restrictions on the vertical relationship between terminals 146 and 148 and semiconductor film 144; the former can be below the latter. The same applies to the vertical relationship between terminals 156 and 158 and semiconductor film 154.

[0046] A planarization film 128 is provided on the first transistor 140 and the second transistor 150 to provide a flat surface due to their unevenness. As an optional configuration, a first interlayer insulating film 126 may be provided between the first transistor 140 and the second transistor 150 and the planarization film 128.

[0047] The above-described structure can be formed by appropriately employing known structures and materials, therefore detailed descriptions are omitted. In short, the substrate 102 can include inorganic insulators such as glass and quartz, semiconductors such as silicon, polymers such as polyimide, polycarbonate, and polyester, and metals such as aluminum, copper, and stainless steel. When a conductive material such as a metal is included, it is preferable to provide a base coating 122 on the surface where the power supply wave reflecting element 120 is disposed, i.e., on the surface of the substrate 102 opposite to the substrate 104. The substrate 102 may or may not transmit visible light. Furthermore, the substrate 102 can be flexible. The base coating 122, the gate insulating film 124, and the first interlayer insulating film 126 can be formed from one or more layers of silicon-containing inorganic compounds such as silicon oxide and silicon nitride. The gate insulating film 124 can be configured as a so-called high-k material including hafnium silicate, nitrogen-containing hafnium silicate, hafnium oxide, nitrogen-added hafnium aluminate, yttrium oxide, etc. Gate line 116, signal line 118, gate electrodes 142 and 152, and terminals 146, 148, 156, and 158 may be configured to contain metals such as titanium, molybdenum, tungsten, copper, and aluminum, or alloys containing metals selected from these metals. Semiconductor films 144 and 154 may contain Group 14 elements such as silicon, or may be formed as oxides containing Group 13 elements such as indium and gallium. Planarization film 128 may be configured to contain polymers such as polyimide, polyamide, acrylic resin, and silicone resin.

[0048] It should be noted that, Figures 2 to 4 In this diagram, only the first transistor 140 and the second transistor 150 are shown between the planarization film 128 and the substrate 102, but each electromagnetic wave reflecting element 120 may also include one or more transistors, one or more capacitors, and other various elements.

[0049] A liquid crystal element 160 is disposed on the planarization film 128. The liquid crystal element 160 has a first electrode (hereinafter referred to as a patch electrode) 162, a second electrode (hereinafter referred to as an auxiliary electrode) 166, a second interlayer insulating film 164, a first alignment film 168 and a second alignment film 172, a liquid crystal layer 170, and a counter electrode 174 as its basic components.

[0050] The patch electrode 162 is electrically connected to a terminal 148 of the first transistor 140 via an opening in the planarization film 128 and the first interlayer insulating film 126. Thus, when the first transistor 140 is turned on, a control signal is applied to the patch electrode 162 via the signal line 118 through the terminal 146, the semiconductor film 144, and the terminal 148. On the other hand, the auxiliary electrode 166 is electrically connected to a terminal 158 of the second transistor 150 via an opening in the planarization film 128, the first interlayer insulating film 126, and the second interlayer insulating film 164. Thus, when the second transistor 150 is turned on, a control signal is applied to the auxiliary electrode 166 via the signal line 118 through the terminal 156, the semiconductor film 154, and the terminal 158. Therefore, by appropriately switching the first transistor 140 and the second transistor 150 on and off, a selectable potential (i.e., a variable potential) can be supplied to the patch electrode 162 and the auxiliary electrode 166. The patch electrode 162 and the auxiliary electrode 166 may be configured to contain the metal or alloy described above, or may contain conductive oxides that exhibit light transmittance, such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0051] There are no restrictions on the shape (planar shape) of the patch electrode 162, but the patch electrode 162 preferably has a shape including a regular polygon with multiple intersecting axes of symmetry, such as a square. By adopting such a shape, both vertically polarized and horizontally polarized waves of the incident radio wave can be reflected efficiently.

[0052] Here, the auxiliary electrode 166 includes at least one, preferably multiple, slits 166a. The slits 166a overlap with the patch electrode 162, thus a portion of the patch electrode 162 is exposed from the auxiliary electrode 166. The length and width of the slits 166a are appropriately selected based on the frequency of the reflected electromagnetic wave. For example, the length is 2 mm to 100 mm or 2 mm to 30 mm, and the width is 1 μm to 100 μm or 1 μm to 10 μm. Therefore, the aspect ratio (length / width) of the slits 166a also depends on the frequency of the reflected electromagnetic wave, for example, 10 to 10000. The number of slits 166a provided in each auxiliary electrode 166 is also appropriately selected based on the frequency of the electromagnetic wave. It should be noted that... Figure 2 In the example shown, the slit 166a extends in a straight line, but each slit 166a may also have one or more bends. Here, a slit refers to an opening provided in the membrane, the outline of which has a closed shape and is independent from the outermost periphery of the membrane.

[0053] Or, such as Figure 5 As shown, the auxiliary electrode 166 may also have one or more notches 166b instead of slits 166a. Therefore, the auxiliary electrode 166 may have a comb-like shape. Here, a notch refers to a defect on the surface of the membrane, its outline having an open shape, forming part of the outermost periphery of the membrane. The notches 166b are located between adjacent comb teeth, and the patch electrode 162 is exposed at the notches 166b. The length, width, and aspect ratio of the notches 166b can also be appropriately set according to the aforementioned ranges related to the length, width, and aspect ratio of the slit 166a.

[0054] The second interlayer insulating film 164 is sandwiched between the patch electrode 162 and the auxiliary electrode 166 to electrically insulate them. Therefore, the second interlayer insulating film 164 can also be composed of one or more films, for example, containing a silicon-containing inorganic compound.

[0055] Both the first alignment film 168 and the second alignment film 172 are configured to cover the patch electrode 162 and the auxiliary electrode 166, and sandwich the liquid crystal layer 170. The first alignment film 168 and the second alignment film 172 are configured to control the orientation of the liquid crystal molecules constituting the liquid crystal layer 170 between them. The first alignment film 168 and the second alignment film 172 can be continuously configured across a plurality of electromagnetic wave reflecting elements 120. In other words, the first alignment film 168 and the second alignment film 172 can be configured to be shared by all electromagnetic wave reflecting elements 120 without being separated between adjacent electromagnetic wave reflecting elements 120.

[0056] Both the first alignment film 168 and the second alignment film 172 contain polymers such as polyimide and polyester. The first alignment film 168 and the second alignment film 172 are formed using wet film-forming methods such as inkjet printing, spin coating, printing, and dip coating, and their surfaces are subjected to a friction treatment. Alternatively, the first alignment film 168 and the second alignment film 172 can also be formed by a photo-alignment treatment. By using a friction treatment or a photo-alignment treatment, the first alignment film 168 and the second alignment film 172 can align liquid crystal molecules in a constant direction along the main surfaces of the substrate 102 and the opposing substrate 104. Therefore, in the absence of an electric field in the liquid crystal layer 170, the liquid crystal molecules are uniformly aligned, and their long axis direction is approximately parallel to the main surface of the substrate 102. The orientation direction (alignment direction) of the liquid crystal molecules in the first alignment film 168 and the second alignment film 172 can be optionally set; it can be parallel or perpendicular to the length direction of the slit 166a or the notch 166b, or it can be tilted at an optional angle from the length direction. Furthermore, the orientation directions of the first orientation film 168 and the second orientation film 172 can be the same or different. For example, the orientation directions of the first orientation film 168 and the second orientation film 172 can be orthogonal to each other.

[0057] The liquid crystal layer 170 contains liquid crystal molecules. The structure of the liquid crystal molecules is not limited. Therefore, the liquid crystal molecules can be nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, or chiral nematic liquid crystals. The thickness of the liquid crystal layer 170 is, for example, 20 μm to 100 μm or 30 μm to 50 μm. Although not shown, spacers for maintaining this thickness throughout the entire electromagnetic wave reflecting device 100 can be provided within the liquid crystal layer 170.

[0058] The counter electrode 174 can be configured as a single electrode integrated across the multiple electromagnetic wave reflecting elements 120 in a manner shared by all of them. Therefore, the counter electrode 174 is also referred to as the common electrode. Since the electromagnetic wave reflecting elements 120 may or may not transmit visible light, the counter electrode 174, like the patch electrode 162 and the auxiliary electrode 166, can also contain the aforementioned metal or alloy, or conductive oxides such as ITO or IZO. A common potential, serving as a constant potential, is supplied to the counter electrode 174 directly or via the signal line drive circuit 108 from an external circuit not shown. Due to the potential difference between the counter electrode 174 and the patch electrode 162 and / or between the counter electrode 174 and the auxiliary electrode 166, a longitudinal electric field is generated in the liquid crystal layer 170. The orientation of the liquid crystal molecules changes due to this longitudinal electric field, thereby controlling the dielectric constant of the liquid crystal layer 170.

[0059] Here, the liquid crystal element 160 is configured such that the distance D2 between the patch electrode 162 and the auxiliary electrode 166 (the distance from the upper surface of the patch electrode 162 to the lower surface of the auxiliary electrode 166) is less than the distance D1 between the auxiliary electrode 166 and the counter electrode 174 (the distance from the upper surface of the auxiliary electrode 166 to the lower surface of the counter electrode 174). The distance D2 is mainly determined by the second interlayer insulating film 164, for example, it is 50 nm or more and 5 μm or less. The distance D1 is mainly determined by the liquid crystal layer 170, the first alignment film 168, and the second alignment film 172. For example, the distance D2 can be set in the range of 100 times or more and 1000 times or more and 500 times the distance D1.

[0060] The opposing substrate 104 can have the same structure as the substrate 102. It is made of sealing material 112 ( Figure 1 The substrate 102 and the opposing substrate 104 are sealed together, and the liquid crystal layer 170 is sealed within the space formed by the sealing material 112, the substrate 102, and the opposing substrate 104. Figure 3 , Figure 4 As shown, a base coating 130 for preventing impurities in the opposing substrate 104 from diffusing towards the liquid crystal layer 170 can be provided on the surface of the opposing substrate 104 on the side of the liquid crystal layer 170. The base coating 130 can also have the same configuration as the base coating 122.

[0061] 2. Driving method of radio wave reflection device The following uses Figures 6 to 12 Explain the driving method of the radio wave reflecting device 100. Figure 6 This is an example of a timing diagram for driving the radio wave reflecting device 100. Here, for a radio wave reflecting element 120, the potential changes applied to the counter electrode 174, patch electrode 162, and auxiliary electrode 166 are schematically shown in seven consecutive frames. Figures 7 to 9 This is a schematic end view of a portion of an electromagnetic wave reflecting element 120. Figures 10 to 12 These are schematic end-view views of multiple radio wave reflecting elements 120. For ease of viewing, only a portion of the configuration is shown in these figures, for example... Figures 10 to 12 Only the patch electrode 162, auxiliary electrode 166, liquid crystal layer 170, and counter electrode 174 are shown. Figures 7 to 9 In the image, ellipses are used to schematically represent liquid crystal molecules.

[0062] according to Figure 6In the timing diagram, the radio wave reflecting device 100 is in the off state in frames 1, 4, and 7. Conversely, in frames 2 and 5, the radio wave reflecting device 100 is in the on state, forming an electric field in the liquid crystal layer 170. Therefore, the reflection direction of the incident radio wave can be controlled in frames 2 and 5. In the example shown here, the electric field strength formed in the liquid crystal layer 170 is different in frames 2 and 5, with the latter being greater than the former. Frames 3 and 6 are also referred to as the overdrive period; as described later, by setting these frames, high-speed switching of the radio wave reflection direction can be achieved.

[0063] (1) Cutoff status In the first frame, the same potential is supplied to the patch electrode 162, auxiliary electrode 166, and counter electrode 174 in all the electromagnetic wave reflecting elements 120. Here, this potential is described as a ground potential (0V), but the potential applied to the patch electrode 162, auxiliary electrode 166, and counter electrode 174 is a relative potential with respect to an optionally determined potential. In this state, these electrodes are at the same potential relative to each other, no electric field is generated in the liquid crystal layer 170, and the liquid crystal molecules in the liquid crystal layer 170 are uniformly oriented according to the orientation directions of the first alignment film 168 and the second alignment film 172. Figure 7 As a result, the dielectric constant of the liquid crystal layer 170 is the same across all the electromagnetic wave reflecting elements 120. Therefore, as shown in the schematic end-face view of the plurality of electromagnetic wave reflecting elements 120... Figure 10 As shown by the dashed arc, the electromagnetic wave incident from the patch electrode 162 side ( Figure 10 The diffusion (phase) of the reflected wave generated by the reflection of the solid hollow arrow (in the image) on the surface of the opposing electrode 174 does not change. Therefore, the incident electromagnetic wave is positively reflected by the electromagnetic wave reflecting device 100, providing a reflected wave with the same angle of incidence as the angle of incidence. Figure 10 (The dashed hollow arrow in the middle).

[0064] (2) On state In the second frame following the first frame, the radio wave reflecting element 120 is turned on. Specifically, the potential V0 of the counter electrode 174 is maintained at 0V, and in each radio wave reflecting element 120, the first transistor 140 is turned on while the second transistor 150 is kept off. In this state, an optional potential (here, a potential of +aV) different from the ground potential is supplied to the patch electrode 162 from the signal line 118. Thus, the potential V of the patch electrode 162... p Become +aV.

[0065] Then, the first transistor 140 is turned off. As a result, the potential V of the patch electrode 162... pThe voltage is maintained at +aV. Next, while maintaining the first transistor 140 in the off state, the second transistor 150 is turned on, in which a selectable potential (here, a potential of +aV) different from the ground potential is supplied from the signal line 118. Thus, the potential V of the auxiliary electrode 166... a This becomes a1V. It should be noted that in the above description, the potential V of the patch electrode 162 is set. p Then set the potential V of the auxiliary electrode 166. a However, their order is optional. Additionally, the potential V of the patch electrode 162... p and the potential V of auxiliary electrode 166 a The electrodes can be the same or different from each other, but it is preferable that these electrodes have the same potential so that no transverse electric field is generated due to the potential difference between the patch electrode 162 and the auxiliary electrode 166.

[0066] Through the above operations, a potential difference is generated between the patch electrode 162 and the counter electrode 174, and between the auxiliary electrode 166 and the counter electrode 174, thus generating a longitudinal electric field within the liquid crystal layer 170 (see...). Figure 8 (The dashed arrow in the image). The potential V of the patch electrode 162 at this time... p and the potential V of auxiliary electrode 166 a The phase change of the reflected wave is determined by the direction of reflection of the incident electromagnetic wave. The phase change depends on the change in the dielectric constant of the liquid crystal layer 170; the greater the change in dielectric constant, the greater the phase change. Furthermore, the change in dielectric constant depends on the electric field strength generated in the liquid crystal layer 170. Therefore, to cause a significant phase change in the reflected wave, a potential V is applied to the patch electrode 162 and the auxiliary electrode 166 in relation to the counter electrode 174. o Significantly different potentials are acceptable.

[0067] When a longitudinal electric field is generated, although the intensity of the electric field also matters, the liquid crystal molecules will stand upright with their long axes aligned close to the direction of the electric field, exhibiting a curved orientation, a vertical orientation, or a similar orientation. As a result, due to the anisotropy of the dielectric constant of the liquid crystal molecules, the dielectric constant of the liquid crystal layer 170 varies. Therefore, by varying the intensity of the longitudinal electric field for each electromagnetic wave reflecting element 120, it is possible to vary the phase of the reflected wave for each electromagnetic wave reflecting element 120. Figure 11 The result is, as Figure 11 As shown by the straight line, it is possible to tilt the equiphase surface of the reflected wave, that is, to tilt the incident electromagnetic wave (…). Figure 11 The change in the reflection direction of the solid line hollow arrow (see) Figure 11 (dashed hollow arrow).

[0068] Depending on the tilt of the phase plane, there are sometimes electromagnetic wave reflecting elements 120 where the phase change of the reflected wave exceeds 360°. In this case, the potential of the patch electrode 162 is controlled by causing the electric field generated in the liquid crystal layer 170 to change periodically. Specifically, as... Figure 12 As shown, the electromagnetic wave reflecting device 100 is driven in such a way that the longitudinal electric field in the liquid crystal layer 170 changes periodically in the row or column direction, thereby forming a unit cycle in the row or column direction of a plurality of electromagnetic wave reflecting elements 120, in which the longitudinal electric field intensity continuously increases or decreases. In each unit cycle, the longitudinal electric field intensity is adjusted in such a way that an equiphase surface, represented by a solid straight line, is formed. Figure 12 In the example shown, the phase change within one unit cycle is continuously varied by θ1, θ2, θ3 (θ1 < θ2 < θ3). Furthermore, during adjacent unit cycles, the radio wave reflecting device 100 is driven such that the phase difference between the equiphase surfaces is 360°. In this way, by driving the radio wave reflecting device 100, a comprehensive equiphase surface, represented by the dashed line, can be obtained, enabling the incident radio waves (… Figure 12 The change in the reflection direction of the solid line hollow arrow (see) Figure 12 (dashed hollow arrow).

[0069] Then, with the radio wave reflecting element 120 returned to the off state, in the third frame, the potential V of the counter electrode 174 is adjusted. o Maintaining the potential V of the patch electrode 162 at 0V p Maintaining the potential V of the auxiliary electrode 166 at +aV is achieved. a Returning to the initial potential of 0V. This creates a potential difference between the patch electrode 162 and the auxiliary electrode 166, resulting in, as... Figure 9 As shown, a lateral electric field is generated between the patch electrode 162 and the auxiliary electrode 166. On the other hand, a potential difference still exists between the patch electrode 162 and the counter electrode 174, but as mentioned above, the distance D1 is much larger than the distance D2, so the longitudinal electric field can be ignored compared to this lateral electric field. As a result, in the third frame, the liquid crystal molecules that were upright in the second frame can be forcibly returned to their original uniform orientation using the lateral electric field. Through the contribution of the driving force brought by this lateral electric field, the orientation of the liquid crystal layer 170 can be quickly returned to its original state. Then, in the fourth frame, by adjusting the potential V of the patch electrode 162... p It returns to the initial potential (0V), thus transitioning to the cutoff state.

[0070] Then, in the case of transitioning to the conduction state that causes a further significant change in the dielectric constant (frame 5), larger potentials are applied to the patch electrode 162 and the auxiliary electrode 166, respectively. Figure 6In the example, the potential is +bV (b>a). Then, the transition back to the cutoff state is the same: in the sixth frame after the fifth frame, no potential difference is set between the auxiliary electrode 166 and the counter electrode 174, but a potential difference is set between the auxiliary electrode 166 and the patch electrode 162, thereby forming a lateral electric field. This allows the alignment state of the liquid crystal layer 170 to quickly return to a uniform alignment.

[0071] It should be noted that in the above example, in the consecutive on-state frames (in this case, frames 2 and 5), the potential V of the patch electrode 162 and the auxiliary electrode 166 is... p and V a The polarity of V relative to the potential of the counter electrode 174 o The properties are the same, but the potential V of the patch electrode 162 and the auxiliary electrode 166 can be changed between frames of continuous conduction states. p and V a The polarity is reversed. By employing this so-called reverse drive, burn-in of the liquid crystal layer 170 can be prevented.

[0072] As described above, in the electromagnetic wave reflecting device 100 according to one embodiment of the present invention, the thickness of the liquid crystal layer 170 is much larger than that of a liquid crystal display device. Therefore, in the same driving method as liquid crystal display devices, such as IPS (In-Plane Switching) liquid crystal display devices, the response speed of the liquid crystal is low, making high-speed switching impossible. This is because, when the liquid crystal molecules return to uniform alignment, only the van der Waals forces between the liquid crystal molecules and the first alignment film 168 and the second alignment film 172 can be utilized. In contrast, in the electromagnetic wave reflecting device 100 according to one embodiment of the present invention, in order to control the reflection direction of the electromagnetic wave, when the liquid crystal molecules, which have been aligned using a longitudinal electric field, return to uniform alignment, the van der Waals forces and the transverse electric field between the auxiliary electrode 166 and the patch electrode 162 can be utilized. Therefore, uniform alignment can be quickly reproduced, and as a result, the reflection characteristics of the electromagnetic wave reflecting device 100 can be switched on and off at high speed. Therefore, by applying one embodiment of the present invention, an electromagnetic wave reflecting device capable of rapidly changing the reflection direction of electromagnetic waves can be provided.

[0073] 3. Variations In the above configuration, two gate lines 116 are arranged in each row, through which the first transistor 140 and the second transistor 150 are controlled independently. On the other hand, in each of the plurality of electromagnetic wave reflecting elements 120 arranged in each column, the first transistor 140 and the second transistor are both electrically connected to the same signal line 118. Therefore, potential is supplied to the patch electrode 162 and the auxiliary electrode 166 from the common signal line 118, respectively.

[0074] The configuration of the radio wave reflecting device 100 according to one embodiment of the present invention is not limited to the configuration described above, and various modifications can be made. For example, such as Figure 13 As shown, a gate line 116 can also be provided in each row, and two signal lines (first signal line 118-1 and second signal line 118-2) can be provided in each column. The first signal line 118-1 and the second signal line 118-2 extend along the column direction. In each row, a portion of each of the first signal line 118-1 and the second signal line 118-2 constitutes terminals 146 and 156 of the first transistor 140 and the second transistor 150, respectively. In other words, the first transistor 140 and the second transistor 150 are connected to different signal lines, namely the first signal line 118-1 and the second signal line 118-2. Therefore, the first signal line 118-1 is electrically connected to the terminal 146 of the first transistor of the plurality of electromagnetic wave reflecting elements 120 arranged in the column in which it is arranged. On the other hand, the second signal line 118-2 is electrically connected to the terminal 156 of the second transistor 150 of the plurality of electromagnetic wave reflecting elements 120 arranged in the column in which it is arranged. The first signal line 118-1 and the second signal line 118-2 are individually controlled by the signal line driving circuit 108 and are supplied with variable potentials. Therefore, in each electromagnetic wave reflecting element 120, optional potentials can be supplied to the first transistor 140 and the second transistor 150 from the first signal line 118-1 and the second signal line 118-2, respectively.

[0075] Gate line 116 extends along the row direction and intersects with first signal line 118-1 and second signal line 118-2. Regarding gate line 116, in each column, a portion functions as the gate electrode 142 of the first transistor 140, and another portion functions as the gate electrode 152 of the second transistor 150. Therefore, considering a wave reflector 120, gate line 116 is electrically connected to the first transistor 140 and the second transistor 150 of that wave reflector 120, and in each wave reflector 120 in the same row as the first wave reflector 120, it is also electrically connected to the first transistor 140 and the second transistor 150. Thus, in each row, the first transistor and the second transistor are simultaneously driven.

[0076] With Figure 2 Similarly, in this modified example of the radio wave reflecting device 100, which includes the radio wave reflecting element 120, the number of signal lines 118 is twice that of a conventional liquid crystal display device. However, the number of radio wave reflecting elements in the reflecting device is significantly reduced compared to the number of pixels in a liquid crystal display device, thus reducing the load on the signal line driving circuit 108. Therefore, it is possible to switch all the radio wave reflecting elements 120 on and off at high speed to supply the corresponding control signals.

[0077] In this modified example, by appropriately selecting the potential supplied via the first signal line 118-1 and the second signal line 118-2 during overdrive, a transverse electric field can also be formed between the patch electrode 162 and the auxiliary electrode 166. Therefore, the liquid crystal molecules that stand upright during conduction can be quickly returned to a uniform orientation, thereby enabling high-speed switching of the direction of electromagnetic wave reflection.

[0078] <Second Implementation Method> In this embodiment, an antenna, a phased array antenna including the antenna, and a method for driving the phased array antenna according to one embodiment of the present invention will be described. Sometimes, descriptions of configurations that are the same as or similar to those described in the first embodiment are omitted.

[0079] 1. Phased array antenna (1) Overall structure of phased array antenna A phased array antenna refers to a plurality of antennas arranged in a straight line or a circle. By adjusting the phase of the AC signal supplied to each antenna, highly directional radio waves can be transmitted in a chosen direction. There is no limitation on the wavelength of the radio waves that can be transmitted using the phased array antenna according to one embodiment of the present invention, for example, in the range of 400 MHz to 50 GHz. This phased array antenna can be used for the transmission of radio waves in typical frequency bands of 400 MHz to 6.0 GHz, 2.5 GHz to 4.7 GHz, and 24 GHz to 50 GHz.

[0080] Figure 14 The diagram shows a schematic top view of the phased array antenna 200. (See diagram for reference.) Figure 14 As shown, the phased array antenna 200 has a substrate 202 and Figure 14 Various patterned insulating films, semiconductor films, conductive films, liquid crystal layers, etc., are disposed between opposing substrates (not shown). By appropriately stacking these films, in addition to multiple antennas 210, a driving circuit 206 for driving each antenna 210 and transmission wiring 208 for transmitting AC signals to the antennas 210 are formed. Multiple terminals (not shown) are formed on the substrate 202, through which various signals are supplied to the driving circuit 206 from an external circuit (not shown). The driving circuit 206 generates signals (scanning signals, control signals) for driving each antenna 210 based on the supplied signals, and transmits these signals via… Figure 14 Wiring, not shown, is supplied to antenna 210. Substrate 202 and opposing substrate are fixed to each other by sealing material 212, which protects multiple antennas 210, drive circuit 206, and transmission wiring 208. A portion of transmission wiring 208 traverses through sealing material 212 and is exposed from opposing substrate.

[0081] Figure 14In the example shown, multiple antennas 210 are arranged in one direction, but there are no restrictions on the arrangement of the antennas 210. For example, the multiple antennas 210 can be arranged in a circle, or they can be arranged in a matrix shape with multiple rows and multiple columns.

[0082] (2) Antenna structure Figure 15 The diagram shows a schematic top view of an antenna 210. Figures 16 to 18 The text shows the directions along the lines. Figure 15 The diagram shows the end face obtained by the dashed lines CC´, DD´, EE´. As shown in these figures, the antenna 210 has an antenna electrode 280, a phase shifter 220, and at least two transistors (a first transistor 240 and a second transistor 250) for driving the phase shifter 220 as its main components.

[0083] Phase shifter 220 is disposed between antenna electrode 280 and transmission wiring 208. Transmission wiring 208 is a conductive film containing metals such as molybdenum, tungsten, titanium, aluminum, and copper, or alloys selected from these metals. It receives AC signal input from a transmitter (not shown) and transmits the AC signal to the phase shifter 220 of each antenna 210 using capacitive coupling. Figure 14 In the example shown, the transmission cabling 208 has a branch structure, with multiple branch ends reaching the vicinity of the corresponding phase shifter 220. Therefore, AC signals with the same phase and frequency are supplied to the phase shifter 220.

[0084] Phase shifter 220 is a component that has the function of changing the phase of an AC signal. By changing the phase amount for each antenna 210, it can give directivity to the radio waves transmitted from the phased array antenna 200 and transmit the radio waves in an optional direction.

[0085] The antenna electrode 280 is also a conductive film containing metal or alloy, as described above, and transmits radio waves at a frequency corresponding to the AC signal input from the phase shifter 220 via capacitive coupling. Therefore, the antenna electrode 280 preferably has a shape including a regular polygon with multiple intersecting axes of symmetry, such as a square. For example, although it also depends on the frequency, it is sufficient to configure the antenna electrode 280 to have a square shape with one side being 2 mm to 30 mm.

[0086] from Figures 15 to 17As can be seen, the phased array antenna 200 has two gate lines (first gate line 214-1 and second gate line 214-2) for supplying scanning signals to multiple antennas 210, and a signal line 216 for supplying control signals. The first gate line 214-1 and the second gate line 214-2 extend along the arrangement direction of the multiple antennas 210 and are electrically connected to all of the antennas 210. On the other hand, the signal lines 118 that intersect with the gate lines 214 are set in the same number as the antennas 210 and are electrically connected to the corresponding antennas 210.

[0087] Each antenna 210 includes at least two transistors (a first transistor 240 and a second transistor 250) for driving the phase shifter 220. A portion of the first gate line 214-1 and a portion of the second gate line 214-2 constitute the gate electrodes of the first transistor 240 and the second transistor 250, respectively. In other words, the first transistor 240 and the second transistor 250 are connected to different gate lines, namely the first gate line 214-1 and the second gate line 214-2. Therefore, the first gate line 214-1 is electrically connected to the gate electrode of the first transistor 240 of all antennas 210. On the other hand, the second gate line 214-2 is electrically connected to the gate electrode of the second transistor 250 of all antennas 210. A potential (scanning signal) is supplied to the first gate line 214-1 and the second gate line 214-2 individually by the driving circuit 206. Therefore, in each antenna 210, the first transistor 240 and the second transistor 250 can be driven and controlled independently of each other. Compared to a conventional liquid crystal display device, the number of gate lines 214 is twice that of a conventional liquid crystal display device. However, generally speaking, the number of antennas provided in a phased array antenna is overwhelmingly reduced compared to the number of pixels provided in a liquid crystal display device, thus reducing the load on the driving circuit 206. Therefore, it is possible to switch the conduction and cutoff of all antennas 210, and more specifically, the phase shifters 220 included in the antennas 210, at high speed.

[0088] Regarding each signal line 216, a portion of it functions as terminal 246 of the first transistor 240, and another portion functions as terminal 256 of the second transistor 250 (see [link]). Figure 15 Therefore, each signal line 216 is electrically connected to the first transistor 240 and the second transistor 250 of an antenna 210, and each transistor is supplied with a separate potential (i.e., a variable potential) as a control signal.

[0089] like Figure 16 and Figure 17 As shown, the first transistor 240 and the second transistor 250 are disposed on the substrate 202 directly or via an undercoating 222, which is an optional configuration. Figure 15 and Figure 16In the example shown, the first transistor 240 is composed of a gate electrode 242, a gate insulating film 224 on the gate electrode 242, a semiconductor film 244 located on the gate insulating film 224 and overlapping the gate electrode 242, and terminals 246 and 248 electrically connected to the semiconductor film 244. Similarly, the second transistor 250 is composed of a gate electrode 252, a gate insulating film 224 on the gate electrode 252, a semiconductor film 254 located on the gate insulating film 224 and overlapping the gate electrode 252, and terminals 256 and 258 electrically connected to the semiconductor film 254. Figures 15 to 17 In the example shown, both transistor 240 and transistor 250 have a bottom-gate structure, but there are no restrictions on their structure. Transistors 240 and 250 can also be top-gate structures, or they can have gate electrodes above and below the semiconductor film. There are also no restrictions on the vertical relationship between terminals 246 and 248 and semiconductor film 244; the former can be below the latter. The same applies to the vertical relationship between terminals 256 and 258 and semiconductor film 254.

[0090] A planarization film 228 is provided on the first transistor 240 and the second transistor 250 to provide a flat surface for absorbing the unevenness caused by them. Optionally, a first interlayer insulating film 226 may be provided between the first transistor 240 and the second transistor 250 and the planarization film 228. In addition to the first transistor 240 and the second transistor 250, each antenna 210 may also include one or more transistors, one or more capacitor elements, and other various components. The configuration from the substrate 102 to the planarization film 228 is the same as that in the first embodiment, therefore further description is omitted.

[0091] Phase shifter 220 is disposed on planarization film 228. Phase shifter 220 has a basic structure consisting of microstrip line 260, second interlayer insulating film 262, auxiliary electrode 264, first alignment film 266 and second alignment film 270, liquid crystal layer 268, and counter electrode 272.

[0092] The microstrip line 260 is electrically connected to a terminal 248 of the first transistor 240 through an opening provided in the planarization film 228 and the first interlayer insulating film 226. Thus, when the first transistor 240 is turned on, a control signal is applied to the microstrip line 260 from the signal line 216 via the terminal 246, the semiconductor film 244, and the terminal 248. The microstrip line 260 is an electrode with a large aspect ratio (e.g., a length / width ratio of 2 to 500). Figure 14 , Figure 15In the example shown, its length direction is arranged perpendicularly to the direction in which the multiple antennas 210 are arranged. The length of the microstrip line 260 can be set to, for example, 1 mm to 10 mm and the width to be set to 20 μm to 500 μm. The microstrip line 260 is constructed to contain metals such as molybdenum, tungsten, titanium, aluminum, and copper, or alloys containing metals selected from these metals.

[0093] Depend on Figure 18 It is understood that the microstrip line 260 can be configured to exist in the same layer as the antenna electrode 280 and the transmission wiring 208. Therefore, the microstrip line 260, the antenna electrode 280, and the transmission wiring 208 can have the same composition and thickness. The microstrip line 260, the antenna electrode 280, and the transmission wiring 208 are isolated from each other and electrically insulated by the second interlayer insulating film 262. The spacing between the microstrip line 260 and the antenna electrode 280, and the spacing between the microstrip line 260 and the transmission wiring 208, can be set, for example, to be more than 1 μm and less than 20 μm.

[0094] On the other hand, the auxiliary electrode 264 is electrically connected to a terminal 258 of the second transistor 250 via openings provided in the planarization film 228, the first interlayer insulating film 226, and the second interlayer insulating film 262. Thus, when the second transistor 150 is turned on, a control signal is applied to the auxiliary electrode 264 from the signal line 216 via the terminal 256, the semiconductor film 254, and the terminal 258. Therefore, by appropriately switching the first transistor 240 and the second transistor 250 on and off, a selectable potential (i.e., a variable potential) can be supplied to the microstrip line 260 and the auxiliary electrode 264. The auxiliary electrode 264 may also be configured to contain the aforementioned metal or alloy, or may contain a transparent conductive oxide such as ITO or indium zinc oxide (IZO). The microstrip line 260 and the auxiliary electrode 264 are electrically insulated by the second interlayer insulating film 262 located between them. The second interlayer insulating film 262 may also be composed of one or more films containing a silicon-containing inorganic compound.

[0095] Here, the auxiliary electrode 264 has at least one, preferably multiple, notches 264a. Figure 15In other words, the auxiliary electrode 264 can have a comb-like shape. The notch 264a overlaps with the microstrip line 260, thus a portion of the microstrip line 260 is exposed from the auxiliary electrode 264. While also depending on the frequency, for example, the length of the notch 264a is 10 μm to 400 μm, the width is 1 μm to 100 μm, and the aspect ratio (length / width) is 2 to 400. The number of notches 264a provided on each auxiliary electrode 264 can be appropriately selected from, for example, a range of 10 to 100. Alternatively, although not shown, similar to the radio wave reflecting element 120 of the first embodiment, each auxiliary electrode 264 can also have one or more slits. The length, width, aspect ratio, and number of the slits can also be appropriately selected from the above ranges.

[0096] Both the first alignment film 266 and the second alignment film 270 are configured to cover the microstrip line 260 and the auxiliary electrode 264, and sandwich the liquid crystal layer 268. The alignment directions of the first alignment film 266 and the second alignment film 270 can be arbitrarily set; they can be parallel or perpendicular to the length direction of the notch 264a (or slit), or they can be tilted at an arbitrary angle from the length direction. In addition, the alignment directions of the first alignment film 266 and the second alignment film 270 can be the same or different. For example, the alignment directions of the first alignment film 266 and the second alignment film 270 can be orthogonal. The configuration of the first alignment film 266, the second alignment film 270, and the liquid crystal layer 268 can adopt the same configuration as that of the first alignment film 168, the second alignment film 172, and the liquid crystal layer 170 of the radio wave reflecting element 120 of the first embodiment, so further description is omitted.

[0097] The counter electrode 272 is disposed on the liquid crystal layer 268 through the second alignment film 270. The counter electrode 272 can be configured as a single electrode integrated across multiple phase shifters 220 in a manner shared by multiple phase shifters 220. Therefore, the counter electrode 272 is also called the common electrode. A common potential, which is a constant potential, is supplied to the counter electrode 272 directly or via the drive circuit 206 from an external circuit not shown. Due to the potential difference between the counter electrode 272 and the microstrip line 260 and / or between the counter electrode 272 and the auxiliary electrode 264, a longitudinal electric field is generated in the liquid crystal layer 268. The orientation of the liquid crystal molecules changes due to this longitudinal electric field, thereby controlling the dielectric constant of the liquid crystal layer 268. The phase shifters 220 may be transparent or opaque to visible light. Therefore, similar to the microstrip line 260 and the auxiliary electrode 264, the counter electrode 272 may also contain the aforementioned metal or alloy, or conductive oxides such as ITO or IZO.

[0098] The phase shifter 220 is configured such that the distance D3 between the microstrip line 260 and the auxiliary electrode 264 (the distance from the upper surface of the microstrip line 260 to the lower surface of the auxiliary electrode 264) is less than the distance D4 between the auxiliary electrode 264 and the counter electrode 272 (the distance from the upper surface of the auxiliary electrode 264 to the lower surface of the counter electrode 272). (See [link to previous section]) Figure 18 The distance D3 is mainly determined by the second interlayer insulating film 262, for example, it is 50 nm to 5 μm. The distance D4 is mainly determined by the liquid crystal layer 268, the first alignment film 266, and the second alignment film 270, and is approximately the sum of the thickness of the liquid crystal layer 268 (for example, 20 μm to 50 μm, or 30 μm to 50 μm) and the thickness of the first alignment film 266 and the second alignment film 270. For example, the distance D4 can be set in the range of 200 times to 500 times the distance D3.

[0099] The opposing substrate 204 can have the same structure as the substrate 202. It is made of sealing material 212 ( Figure 14 The substrate 102 and the opposing substrate 104 are sealed together, and the liquid crystal layer 268 is sealed within the space formed by the sealing material 212, the substrate 202, and the opposing substrate 204. Figures 16 to 18 As shown, a base coating 230 for preventing impurities in the opposing substrate 204 from diffusing towards the liquid crystal layer 268 can be provided on the surface of the opposing substrate 204 on the side of the liquid crystal layer 268. The base coating 230 can also have the same configuration as the base coating 222.

[0100] 2. Driving methods for phased array antennas The following uses Figures 19 to 21 Explain the driving method of the phased array antenna 200. Figure 19 This is an example of a timing diagram for driving a phased array antenna 200. Here, for one antenna 210, the potential changes applied to the counter electrode 272, microstrip line 260, and auxiliary electrode 264 are schematically shown over seven consecutive frames. Figure 20 and Figure 21 This is a schematic end view of the liquid crystal layer 268 and the antenna electrodes 280 of the plurality of antennas 210.

[0101] according to Figure 19 In the timing diagram, phase shifter 220 is in the off state in frames 1, 4, and 7. Conversely, in frames 2 and 5, phase shifter 220 is in the on state, forming an electric field in the liquid crystal layer 268. Therefore, the transmission direction of the radio wave can be controlled in frames 2 and 5. In the example shown here, the electric field strength formed in the liquid crystal layer 268 is different in frames 2 and 5, with the latter being greater than the former. Frames 3 and 6 are also referred to as overdrive periods; as described later, by setting these frames, high-speed switching of the radio wave transmission direction can be achieved.

[0102] (1) Cutoff status In the first frame, the same potential (e.g., 0V ground potential) is supplied to the microstrip line 260, auxiliary electrode 264, and counter electrode 272 in all antennas 210. In this state, these components are at the same potential, and no electric field is generated in the liquid crystal layer 268. Therefore, although not shown, similar to the liquid crystal layer 170 of the electromagnetic wave reflecting element 120 in the first embodiment, the liquid crystal molecules in the liquid crystal layer 268 are uniformly aligned according to the orientation directions of the first alignment film 266 and the second alignment film 270. As a result, the dielectric constant of the liquid crystal layer 170 is the same across all antennas 210. The phase of the AC signal transmitted from the transmission wiring 208 to the microstrip line 260 varies according to the dielectric constant of the liquid crystal layer 268. In the off state, the dielectric constant of the liquid crystal layer 170 is the same across all phase shifters 220, thus as shown in the schematic end view of the plurality of antennas 210. Figure 20 As shown by the dashed arc, the spread (phase) of the radio waves transmitted from the top and bottom of the antenna electrode 280 is the same. Therefore, the radio waves are transmitted towards the front direction of the phased array antenna 200 (the side where the antenna electrode 280 is located) in a direction pointing towards the normal direction of the antenna electrode 280 (see [reference]). Figure 20 (The arrow in the image).

[0103] (2) On state In the second frame following the first frame, phase shifter 220 is turned on. Specifically, the potential V0 of the counter electrode 272 is maintained at 0V, and in each phase shifter 220, the first transistor 240 is turned on while the second transistor 250 is kept off. In this state, an optional potential (here, a potential of +aV) different from the potential V0 of the counter electrode 272 is supplied from signal line 216 to microstrip line 260. Thus, the potential V of microstrip line 260... m Become +aV.

[0104] Then, the first transistor 240 is turned off. Consequently, the potential V of the microstrip line 260... m The voltage is maintained at +aV. Next, while maintaining the first transistor 240 in the off state, the second transistor 250 is turned on, in which a selectable potential (here, a potential of +aV) different from the potential V0 is supplied from the signal line 216. Thus, the potential V of the auxiliary electrode 264... a It becomes +aV. It should be noted that in the above explanation, the potential V of the microstrip line 260 is set. m Then set the potential V of the auxiliary electrode 264. a However, their order is optional. Additionally, the potential V of microstrip line 260... m and the potential V of auxiliary electrode 264a The electrodes can be the same or different from each other, but it is preferable that these electrodes have the same potential so that no transverse electric field is generated due to the potential difference between the microstrip line 260 and the auxiliary electrode 264.

[0105] Through the above operations, a potential difference is generated between the microstrip line 260 and the counter electrode 272, and between the auxiliary electrode 264 and the counter electrode 272. As a result, although not shown, a longitudinal electric field is generated within the liquid crystal layer 268, similar to the liquid crystal layer 170 of the electromagnetic wave reflecting element 120 in the first embodiment (see...). Figure 8 (The dashed arrow in the image). The potential V of the microstrip line 260 at this point... m and the potential V of auxiliary electrode 264 a The phase of the AC signal transmitted via the microstrip line 260 is determined by the direction of the radio wave transmission. As described above, the phase of the AC signal transmitted via the microstrip line 260 varies according to the dielectric constant of the liquid crystal layer 268; the greater the change in dielectric constant, the greater the phase change. Furthermore, the change in dielectric constant depends on the electric field strength generated in the liquid crystal layer 268. Therefore, to cause a significant phase change in the AC signal, a potential V relative to the counter electrode 272 is applied to the microstrip line 260 and the auxiliary electrode 264. o Significantly different potentials are acceptable.

[0106] Similar to the electromagnetic wave reflecting element 120 in the first embodiment, when a longitudinal electric field is generated, the liquid crystal molecules stand upright. As a result, due to the anisotropy of the dielectric constant of the liquid crystal molecules, the dielectric constant of the liquid crystal layer 268 changes. Therefore, by varying the intensity of the longitudinal electric field for each phase shifter 220, the phase of the AC signal can be varied for each antenna 210. The result is that... Figure 21 As shown by the dashed semicircle, the phase of the radio wave transmitted from the antenna electrode 280 can be changed for each antenna 210, causing the equiphase surface to tilt, that is, the direction of the radio wave transmitted to the antenna electrode 280 side can be changed (see...). Figure 21 (Hollow arrow).

[0107] Then, with the phase shifter 220 returned to the off state, in the third frame, the potential V of the counter electrode 272 is adjusted. o Maintaining the potential V of the microstrip line at 260° at 0V m Maintaining the potential V of the auxiliary electrode 264 at +aV. a Returning to the initial potential of 0V, a potential difference is generated between the microstrip line 260 and the auxiliary electrode 264. As a result, similar to the liquid crystal layer 170 of the electromagnetic wave reflecting element 120, a transverse electric field is generated between the microstrip line 260 and the auxiliary electrode 264 (see [link to relevant documentation]). Figure 9On the other hand, a potential difference still exists between microstrip line 260 and counter electrode 272, but as mentioned above, distance D3 is much larger than distance D4, so the longitudinal electric field can be ignored compared to the transverse electric field. As a result, in the third frame, the liquid crystal molecules that were upright in the second frame can be forced back to their original uniform orientation using the transverse electric field. With the contribution of the driving force brought by the transverse electric field, the dielectric constant of liquid crystal layer 268 can be rapidly restored to its original dielectric constant. Then, in the fourth frame, by adjusting the potential V of microstrip line 260... m It returns to the initial potential (0V), thus transitioning to the cutoff state.

[0108] Then, in the case of transitioning to the conduction state that causes a further significant change in the dielectric constant (frame 5), larger potentials are applied to the microstrip line 260 and the auxiliary electrode 264, respectively. Figure 19 In the example, the potential is +bV (b>a). Then, the transition to the cutoff state is the same: in the sixth frame after the fifth frame, no potential difference is set between the auxiliary electrode 264 and the counter electrode 272, but a potential difference is set between the auxiliary electrode 264 and the microstrip line 260, thereby forming a lateral electric field. This allows the alignment state of the liquid crystal layer 268 to quickly return to a uniform alignment.

[0109] It should be noted that, similar to the radio wave reflecting element 120, the phase shifter 220 can also employ inverted driving to prevent burn-in of the liquid crystal layer 268. That is, the potential V of the microstrip line 260 and the auxiliary electrode 264 can be adjusted between consecutive on-frame states. m and V a The polarity of V relative to the potential of the counter electrode 174 o In other words, it's a reversal.

[0110] As described above, similar to the radio wave reflecting device 100, in the antenna 210 and the phased array antenna 200 equipped with the antenna 210 according to one embodiment of the present invention, when the liquid crystal molecules erected by the longitudinal electric field are brought back to a uniform orientation, van der Waals forces and the transverse electric field between the auxiliary electrode 264 and the microstrip line 260 can also be utilized. Therefore, a uniform orientation can be rapidly reproduced, and as a result, the radio wave transmission direction of the phased array antenna 200 can be switched on and off at high speed. Therefore, by applying one embodiment of the present invention, a phased array antenna capable of rapidly changing the radio wave transmission direction can be provided.

[0111] As embodiments of the present invention, the above-described embodiments can be appropriately combined and implemented as long as they do not contradict each other. Furthermore, embodiments in which those skilled in the art appropriately add, delete, or design changes to the constituent elements or design of the radio wave reflecting elements or devices based on the various embodiments, or embodiments in which steps are added, omitted, or conditions are changed, are included within the scope of the present invention as long as they possess the spirit of the present invention.

[0112] Even if other effects are different from those achieved through the above-described embodiments, if they are clearly known from the description in this specification or can be easily predicted by those skilled in the art, they shall of course be understood as effects achieved through the present invention.

[0113] Explanation of reference numerals in the attached figures 100: Radio wave reflecting device; 102: Substrate; 104: Opposing substrate; 106: Scan line driving circuit; 108: Signal line driving circuit; 110: Terminal; 112: Sealing material; 116: Gate line; 116-1: First gate line; 116-2: Second gate line; 118: Signal line; 118-1: First signal line; 118-2: Second signal line; 120: Radio wave reflecting element; 122: Undercoat layer; 124: Gate insulating film; 126: First interlayer insulation. 128: Planarization film; 130: Undercoat layer; 140: First transistor; 142: Gate electrode; 144: Semiconductor film; 146: Terminal; 148: Terminal; 150: Second transistor; 152: Gate electrode; 154: Semiconductor film; 156: Terminal; 158: Terminal; 160: Liquid crystal element; 162: Patch electrode; 164: Second interlayer insulating film; 166: Auxiliary electrode; 166a: Slit; 166b: Notch; 168: First alignment film; 170: Liquid crystal element. Crystal layer, 172: Second alignment film, 174: Counter electrode, 200: Phased array antenna, 202: Substrate, 204: Counter substrate, 206: Driving circuit, 208: Transmission wiring, 210: Antenna, 212: Encapsulation material, 214: Gate line, 214-1: First gate line, 214-2: Second gate line, 216: Signal line, 220: Phase shifter, 222: Undercoat layer, 224: Gate insulating film, 226: First interlayer insulating film, 228: Planarization film, 23 0: Undercoat layer, 240: First transistor, 242: Gate electrode, 244: Semiconductor film, 246: Terminal, 248: Terminal, 250: Second transistor, 252: Gate electrode, 254: Semiconductor film, 256: Terminal, 258: Terminal, 260: Microstrip line, 262: Second interlayer insulating film, 264: Auxiliary electrode, 264a: Notch, 266: First alignment film, 268: Liquid crystal layer, 270: Second alignment film, 272: Counter electrode, 280: Antenna electrode.

Claims

1. An electromagnetic wave reflecting element, which possesses: Patch electrodes; The insulating film on the patch electrode; An auxiliary electrode, located on the insulating film, having at least one slit or notch overlapping the patch electrode; The liquid crystal layer on the auxiliary electrode; and The opposing electrode on the liquid crystal layer The patch electrode and the auxiliary electrode are configured to be individually applied with variable potentials.

2. The electromagnetic wave reflecting element as described in claim 1, wherein, The distance between the auxiliary electrode and the counter electrode is greater than the distance between the auxiliary electrode and the patch electrode.

3. The electromagnetic wave reflecting element as described in claim 1, wherein, The counter electrode is configured to be subjected to a constant potential.

4. The electromagnetic wave reflecting element as claimed in claim 1, further comprising a first transistor and a second transistor electrically connected to the patch electrode and the auxiliary electrode, respectively.

5. The radio wave reflecting element as described in claim 1, further comprising: The first alignment film between the auxiliary electrode and the liquid crystal layer; and The second alignment film between the liquid crystal layer and the counter electrode.

6. An electromagnetic wave reflecting device comprising a plurality of electromagnetic wave reflecting elements configured in a matrix shape having multiple rows and multiple columns. Each of the plurality of electromagnetic wave reflecting elements has: Patch electrodes; The insulating film on the patch electrode; An auxiliary electrode, located on the insulating film, having at least one slit or notch overlapping the patch electrode; The liquid crystal layer on the auxiliary electrode; and The counter electrode is located on the liquid crystal layer and is shared by the plurality of electromagnetic wave reflecting elements. The patch electrode and the auxiliary electrode are configured to be individually applied with variable potentials.

7. The radio wave reflecting device as described in claim 6, wherein, The distance between the auxiliary electrode and the counter electrode is greater than the distance between the auxiliary electrode and the patch electrode.

8. The radio wave reflecting device as described in claim 6, wherein, The counter electrode is configured to be subjected to a constant potential.

9. The radio wave reflecting device as described in claim 6, wherein, Each of the plurality of electromagnetic wave reflecting elements also includes a first transistor and a second transistor, which are electrically connected to the patch electrode and the auxiliary electrode, respectively.

10. The radio wave reflecting device as claimed in claim 6, wherein, Each of the plurality of radio wave reflecting elements also possesses: The first alignment film between the auxiliary electrode and the liquid crystal layer; and The second alignment film between the liquid crystal layer and the counter electrode.

11. The radio wave reflecting device as claimed in claim 9, further comprising: The first gate line and the second gate line extending along the row direction; and The signal lines that intersect the first gate line and the second gate line, The first gate line is electrically connected to the first transistor of the first electromagnetic wave reflecting element selected from the plurality of electromagnetic wave reflecting elements. The second gate line is electrically connected to the second transistor of the first electromagnetic wave reflecting element. The signal line is electrically connected to the first transistor and the second transistor of the first electromagnetic wave reflecting element.

12. The radio wave reflecting device as claimed in claim 11, wherein, The signal line is electrically connected to the first transistor and the second transistor, which are selected from the plurality of electromagnetic wave reflecting elements and are located in the same column as the first electromagnetic wave reflecting element in the second electromagnetic wave reflecting element.

13. The radio wave reflecting device as claimed in claim 9, further comprising: Gate lines extending along the row direction; and The first signal line and the second signal line that intersect the gate line, The gate line is electrically connected to the first transistor and the second transistor of the first electromagnetic wave reflecting element selected from the plurality of electromagnetic wave reflecting elements. The first signal line is electrically connected to the first transistor of the first electromagnetic wave reflecting element. The second signal line is electrically connected to the second transistor of the first electromagnetic wave reflecting element.

14. The radio wave reflecting device as claimed in claim 13, wherein, The gate line is electrically connected to the first transistor and the second transistor, which are selected from the plurality of electromagnetic wave reflecting elements and are located in the same row as the first electromagnetic wave reflecting element in a second electromagnetic wave reflecting element.

15. An antenna, which includes antenna electrodes and a phase shifter. The phase shifter has: The microstrip line exists in the same layer as the antenna electrode; The insulating film on the microstrip line; An auxiliary electrode is located on the insulating film and has at least one slit or notch overlapping the microstrip line; The liquid crystal layer on the auxiliary electrode; and The opposing electrode on the liquid crystal layer The antenna electrodes are electrically insulated from the microstrip line through the insulating film.

16. The antenna as claimed in claim 15, wherein, The distance between the auxiliary electrode and the counter electrode is greater than the distance between the auxiliary electrode and the microstrip line.

17. The antenna of claim 15, further comprising: The transmission cabling exists in the same layer as the microstrip line and is electrically insulated from the microstrip line by the insulating film.

18. The antenna as claimed in claim 15, wherein, The microstrip line and the auxiliary electrode are configured to be individually subjected to variable potentials. The counter electrode is configured to be subjected to a constant potential.

19. The antenna of claim 15, further comprising a first transistor and a second transistor electrically connected to the microstrip line and the auxiliary electrode, respectively.

20. The antenna of claim 15, further comprising: The first alignment film between the auxiliary electrode and the liquid crystal layer; and The second alignment film between the liquid crystal layer and the counter electrode.

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