Electromagnetic wave control element

Abstract

The present invention addresses the problem of providing an electromagnetic wave control element which has little variation in the reflectance of electromagnetic waves in a plane. The present invention comprises, in the following order: a metasurface member including a metasurface structure in which a plurality of fine structures are arranged; an intermediate layer disposed in contact with the metasurface member; and a liquid crystal film disposed in contact with the intermediate layer and including a liquid crystal layer in which the orientation of a liquid crystal compound is fixed.

Description

Technical Field

[0001] The present invention relates to an element for electromagnetic wave control using a metasurface structure. Background Art

[0002] High-frequency radio waves (millimeter waves and terahertz waves) required for high-capacity wireless communications have high straightness. Therefore, for example, in order to transmit radio waves to the entire area of ​​a room, a reflector installed on a wall or the like is required to bend the radio waves in any direction.

[0003] However, a typical reflector is a regular reflector, and the incident angle and the outgoing angle are equal, so there is a problem that, for example, radio waves have difficulty reaching the deep part of the room.

[0004] On the other hand, there has been proposed a device that uses a dynamic element such as liquid crystal to bend and reflect electromagnetic waves in a direction different from regular reflection.

[0005] For example, in non-patent document 1, Figure 8 As conceptually shown in FIG. 1 , an electromagnetic wave control element (light beam steering element) is described in which a liquid crystal layer 104 is sandwiched between a metasurface structure 100 and an electrode layer 102 .

[0006] exist Figure 8 In the electromagnetic wave controlling element shown, the metasurface structure 100 is formed by arranging fine structures 100a that serve as resonators, similarly to known metasurface structures.

[0007] In this electromagnetic wave controlling element, each of the fine structures 100a constituting the metasurface structure 100 functions not only as a reflector but also as an electrode. That is, the fine structures 100a and the electrode layer 102 form an electrode pair.

[0008] Furthermore, the electrode layer 102 also functions as a reflection layer for incident electromagnetic waves.

[0009] As an example, the liquid crystal layer 104 is a layer formed by aligning a liquid crystal compound LC. Figure 8 In the example shown, the liquid crystal compound LC is, as an example, a rod-shaped liquid crystal compound.

[0010] In this electromagnetic wave controlling element, when no voltage is applied between the fine structure 100 a and the electrode layer 102 , the longitudinal direction of the liquid crystal compound LC, that is, the direction of the optical axis, is aligned with the thickness direction.

[0011] When a voltage is applied between the fine-structure body 100 a and the electrode layer 102 in this state, the alignment state of the liquid crystal compound LC changes depending on the magnitude of the applied voltage.

[0012] In the example shown in the figure, as an example, the liquid crystal compound LC is tilted with respect to the thickness direction according to the magnitude of the voltage applied between the fine structure body 100 a and the electrode layer 102 .

[0013] exist Figure 8 As an example, a high voltage is applied to the microstructure 100a on the left side of the figure, and a low voltage is applied to the microstructure 100a on the right side of the figure. As a result, the liquid crystal compound LC in the region of the microstructure 100a on the left side of the figure is greatly tilted, and the length direction is close to the main surface of the liquid crystal layer 104. On the other hand, the liquid crystal compound LC in the region of the microstructure 100a on the right side of the figure is tilted less, and the length direction is close to the thickness direction of the liquid crystal layer 104.

[0014] The greater the tilt of the liquid crystal compound LC, that is, the closer the length direction of the liquid crystal compound LC is to the surface of the liquid crystal layer 104, the greater the refractive index of the liquid crystal layer 104. On the contrary, the smaller the tilt of the liquid crystal compound LC, that is, the closer the length direction of the liquid crystal compound LC is to the thickness direction of the liquid crystal layer 104, the smaller the refractive index of the liquid crystal layer 104.

[0015] Therefore, in this state, the refractive index of the liquid crystal layer 104 is large in the region of the microstructure 100a on the left side of the figure where the inclination of the liquid crystal compound LC is large, and is small in the region of the microstructure 100a on the right side of the figure where the inclination of the liquid crystal compound LC is small.

[0016] Therefore, in the region of the microstructure 100a on the left side of the figure having a large refractive index, the phase of the incident electromagnetic wave changes more greatly than in the region of the microstructure 100a on the right side of the figure having a small refractive index.

[0017] Therefore, in the region of the fine-structure body 100a on the left side in the figure, the optical path of the electromagnetic wave is apparently longer than that of the region of the fine-structure body 100a on the right side in the figure.

[0018] Therefore, when electromagnetic waves are incident from the normal direction of the liquid crystal layer 104, even if the electromagnetic waves are incident at the same time, the electromagnetic waves incident on the area of ​​the microstructure 100a on the left side of the figure where the optical path length is long are emitted from the reflecting device more slowly than the electromagnetic waves incident on the area of ​​the microstructure 100a on the right side of the figure where the optical path length is short.

[0019] As a result, the electromagnetic wave incident on the reflecting device from the normal direction and reflected is reflected obliquely to the left side in the figure so that the wave surfaces are aligned, rather than being specularly reflected in the normal direction.

[0020] Previous technical literature

[0021] Non-patent literature

[0022] Non-patent literature 1: Jingbo Wu et al., Liquid crystal programmable metasurface for terahertz beam steering, Applied Physics Letters, 116, 131104 (2020) Summary of the invention

[0023] Technical issues to be solved by the invention

[0024] In the electromagnetic wave control element described in Non-Patent Document 1, the orientation of the liquid crystal compound constituting the liquid crystal layer is not fixed, and the reflection direction of the electromagnetic wave is changed by changing the orientation of the liquid crystal compound in the liquid crystal layer.

[0025] On the other hand, as an electromagnetic wave control element formed by combining a metasurface structure and a liquid crystal layer containing a liquid crystal compound, there is also known a structure in which the liquid crystal compound constituting the liquid crystal layer is fixed.

[0026] Here, according to the research conducted by the inventors, in an electromagnetic wave control element formed by combining a metasurface structure and a liquid crystal layer in which a liquid crystal compound is fixed, the reflectivity of electromagnetic waves within a plane has a large deviation, and this needs to be improved.

[0027] The object of the present invention is to solve the problems of the prior art and to provide an electromagnetic wave control element having a metasurface structure and a liquid crystal layer having a liquid crystal compound fixed thereto, and having a small deviation in the reflectivity of electromagnetic waves within the plane.

[0028] Means for solving technical problems

[0029] In order to solve the problem, the present invention has the following structure.

[0030] [1] An electromagnetic wave control element comprising:

[0031] A metasurface component, comprising a metasurface structure composed of a plurality of microstructures;

[0032] an intermediate layer disposed in contact with the metasurface component; and

[0033] The liquid crystal film is arranged in contact with the intermediate layer and includes a liquid crystal layer in which the orientation of the liquid crystal compound is fixed.

[0034] And the middle layer is an adhesive layer or an orientation layer.

[0035] [2] The electromagnetic wave control element according to [1], wherein:

[0036] The metasurface structure acts on electromagnetic waves with a frequency of 0.1 to 0.3 THz.

[0037] [3] The electromagnetic wave control element according to [1] or [2], wherein:

[0038] The thickness of the intermediate layer is 50 μm or less.

[0039] [4] The electromagnetic wave control element according to any one of [1] to [3], wherein

[0040] A reflective layer is provided on the side of the metasurface component opposite to the intermediate layer or on the side of the liquid crystal film opposite to the intermediate layer.

[0041] [5] The electromagnetic wave control element according to any one of [1] to [4], wherein the intermediate layer is in contact with the liquid crystal layer.

[0042] [6] The electromagnetic wave control element according to any one of [1] to [5], wherein the intermediate layer is in contact with the metasurface structure.

[0043] Effects of the Invention

[0044] According to the present invention, there is provided an electromagnetic wave control element having a metasurface structure and a liquid crystal layer to which a liquid crystal compound is fixed, and having small deviation in reflectance of electromagnetic waves within a plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a diagram conceptually showing an example of the electromagnetic wave controlling element of the present invention.

[0046] Figure 2 This is a diagram conceptually showing an example of a metasurface structure.

[0047] Figure 3 This is a conceptual diagram for explaining a liquid crystal layer.

[0048] Figure 4 This is a diagram conceptually showing another example of the electromagnetic wave controlling element of the present invention.

[0049] Figure 5 This is a diagram conceptually showing another example of the electromagnetic wave controlling element of the present invention.

[0050] Figure 6 This is a diagram conceptually showing another example of the electromagnetic wave controlling element of the present invention.

[0051] Figure 7 This is a diagram conceptually showing another example of the electromagnetic wave controlling element of the present invention.

[0052] Figure 8This is a diagram conceptually showing an example of a conventional electromagnetic wave controlling element. DETAILED DESCRIPTION

[0053] Hereinafter, the electromagnetic wave controlling element of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

[0054] In the present specification, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0055] In this specification, “the same” includes an error range generally allowed in the technical field.

[0056] The following figures are conceptual diagrams for explaining the electromagnetic wave control element of the present invention, and therefore, the shape, size, thickness, positional relationship, etc. of each component may not necessarily be the same as the actual one.

[0057] Figure 1 1 conceptually shows an example of the electromagnetic wave controlling element of the present invention.

[0058] Figure 1 The electromagnetic wave controlling element 10 shown includes, from the top of the figure, an alignment layer 12 , a liquid crystal layer 14 , an adhesive layer 16 , a metasurface structure 18 , and a reflective layer 24 .

[0059] The super surface structure 18 is composed of a plurality of microstructures arranged on a support 20. The super surface structure 18 shown in the figure is composed of three types of microstructures 28a, 28b, and 28c arranged on a support 20.

[0060] In the electromagnetic wave control element 10, as an example, the support 20 and the metasurface structure 18 constitute the metasurface component of the present invention, and the liquid crystal layer 14 and the alignment layer 12 constitute the liquid crystal film of the present invention. In addition, in the electromagnetic wave control element 10, the adhesive layer 16 becomes the intermediate layer of the present invention.

[0061] The electromagnetic wave controlling element 10 shown in the figure is composed of a metasurface member (metasurface structure 18 ) and a liquid crystal film (liquid crystal layer 14 ) bonded together via an adhesive layer 16 as an intermediate layer.

[0062] Figure 2 A top view of the metasurface structure 18 is conceptually shown in FIG.

[0063] The top view is a view of the electromagnetic wave controlling element 10 viewed from the stacking direction of each layer. In other words, the top view is a view of the electromagnetic wave controlling element 10 viewed from the normal direction of the main surface of each layer constituting the electromagnetic wave controlling element 10.

[0064] Here, the main surface refers to the largest surface of a sheet-like object (film, plate-like object, layer, membrane), usually both surfaces in the thickness direction.

[0065] Furthermore, the normal direction refers to a direction perpendicular to a plane or the like. That is, in the electromagnetic wave controlling element 10 , the normal direction refers to a direction perpendicular to the main surface of each layer.

[0066] exist Figure 2 In the example shown, the microstructures constituting the supersurface structure 18 are two-dimensionally arranged on one main surface of a sheet-like support 20 in the X direction and the Y direction that are orthogonal to each other.

[0067] In addition, Figure 1 In the figure, the X direction is the lateral direction toward the right side in the figure, and the Y direction is the direction toward the inner side perpendicular to the paper surface in the figure.

[0068] Specifically, it is assumed that on the main surface of the support 20, Figure 2 The square regions with a side length of P1 indicated by the dotted line are arranged two-dimensionally in the x direction and the y direction. In the following description, for convenience, the square region with a side length of P1 is also referred to as "region P1".

[0069] Furthermore, the microstructures constituting the super surface structure 18 are plate-shaped with a square plane shape. The super surface structure 18 has three types of microstructures, namely, the smallest microstructure 28a, the largest microstructure 28c, and the intermediate microstructure 28b. Each microstructure is configured so that the direction of the square coincides with the center of the region P1 assumed to be the support body 20.

[0070] And, if Figure 2 As shown, in the super surface structure 18, the order of the microstructure 28a, the microstructure 28b and the microstructure 28c is repeatedly arranged in the X direction. That is, in the super surface structure 18, in the X direction, the microstructures are arranged in the manner of the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, the microstructure 28c, the microstructure 28b, the microstructure 28c, the microstructure 28a, the microstructure 28b, ...

[0071] On the other hand, the same fine structures are arranged in the Y direction.

[0072] The metasurface structure 18 performs phase modulation of an incident electromagnetic wave by utilizing the resonance of the microstructure as a resonator due to the arrangement of unit cells composed of one microstructure and the space in the imaginary square region P1.

[0073] Here, as a preferred embodiment, the metasurface structure 18 shown in the figure acts on electromagnetic waves with a frequency of 0.1 to 0.3 THz and modulates the phase of the electromagnetic waves of this frequency. That is, as a preferred embodiment, the metasurface structure 18 acts on electromagnetic waves with a wavelength of 1 to 3 mm and modulates the phase of the electromagnetic waves of this wavelength.

[0074] Furthermore, a reflection layer 24 for reflecting electromagnetic waves with a frequency of 0.1 to 0.3 THz is provided on the surface of the support body 20 opposite to the metasurface structure 18 .

[0075] That is, in Figure 1 In the electromagnetic wave controlling element 10 shown, the reflective layer 24 is provided on the side of the metasurface member opposite to the adhesive layer 16 (intermediate layer).

[0076] The liquid crystal layer 14 is a layer in which a liquid crystal compound is aligned and fixed.

[0077] In the electromagnetic wave control element 10 of the present invention, the liquid crystal layer 14 also modulates the phase of the incident electromagnetic wave in the same manner as the metasurface structure 18 .

[0078] In the electromagnetic wave control element 10 having such a metasurface structure 18, a liquid crystal layer 14 and a reflective layer 24, the phase of the electromagnetic wave incident from the orientation layer 12 side is modulated by the liquid crystal layer 14 and the metasurface structure 18, and the phase of the electromagnetic wave reflected by the reflective layer 24 is modulated again by the metasurface structure 18 and the liquid crystal layer 14 and emitted.

[0079] Thus, the electromagnetic wave controlling element 10 reflects the incident electromagnetic wave in a direction different from the direction of specular reflection (regular reflection).

[0080] For example, when an electromagnetic wave enters the liquid crystal layer 14 in the normal direction, the electromagnetic wave is reflected in a direction tilted with respect to the normal direction, rather than being reflected in the normal direction.

[0081] As described above, the super-surface structure 18 is composed of fine structures arranged on one surface of the support 20 .

[0082] The support 20 is not limited, and any of various known sheet-like materials can be used as long as it can support the microstructure and transmit the electromagnetic waves acted on by the metasurface structure 18, that is, electromagnetic waves with a frequency of 0.1 to 0.3 THz.

[0083] In the following description, unless otherwise specified, electromagnetic waves refer to electromagnetic waves of this frequency.

[0084] As the support 20, for example, there can be illustrated a metal substrate having an oxide insulating layer such as a silicon substrate having silicon oxide, a substrate composed of an oxide such as silicon oxide, a semiconductor substrate such as a germanium substrate and a chalcogenide glass substrate, a polyacrylic resin film such as polymethyl methacrylate, a cellulose resin film such as cellulose triacetate, a cycloolefin polymer film, a polyethylene terephthalate (PET) film, a resin film such as a polycarbonate film and a polyvinyl chloride film, and a glass plate, etc. As commercial products of cycloolefin polymer films, for example, the trade name "ARTON" manufactured by JSR Corporation and the trade name "ZEONOR" manufactured by ZEON CORPORATION, etc. can be illustrated.

[0085] The thickness of the support 20 is not limited either, as long as it is appropriately set according to the material forming the support 20 so as to support the microstructure, obtain the required transmittance to electromagnetic waves, and obtain sufficient strength according to the purpose of the electromagnetic wave control element 10.

[0086] In addition, in the electromagnetic wave controlling element 10 of the present invention, the metasurface structure 18 is not limited to having the support 20 .

[0087] That is, in the electromagnetic wave controlling element of the present invention, if possible, a microstructure may be arranged on the surface of another layer such as an intermediate layer to form a super-surface structure 18 .

[0088] A plurality of fine structures are arranged on one surface of the support 20. The super surface structure 18 is formed by the arrangement of the fine structures.

[0089] As described above, the super surface structure 18 is a structure formed by separating microstructures and arranging them two-dimensionally on a plane, and is basically composed of an arrangement of unit cells formed by a microstructure and the space around the microstructure. In the example shown in the figure, a unit cell is composed of a microstructure and a square region P1 with one side of the microstructure being P1.

[0090] Furthermore, in the example shown in the figure, three fine structures 28 a , 28 b , and 28 c having different sizes are arranged to form the super-surface structure 18 .

[0091] In the electromagnetic wave control element of the present invention, the metasurface structure is basically a known metasurface structure (metamaterial). Therefore, in the electromagnetic wave control element 10 of the present invention, the metasurface structure is not limited to Figure 2 The structures shown in the above can utilize various well-known metasurface structures.

[0092] That is, in the present invention, there are no limitations on the shape and forming material of the microstructure, the arrangement of the microstructure, the interval (pitch) between the microstructures, the planar shape and size of the unit cell, and the like.

[0093] Furthermore, the reflection characteristics of the electromagnetic waves acted on by the element 10 for electromagnetic wave control according to the present invention can be designed by a known method. As an example, the amplitude and phase of the electromagnetic wave modulated by the phase of the microstructure used can be calculated using commercially available simulation software, and the arrangement of the microstructure can be set in a manner that becomes the distribution of the target phase modulation amount.

[0094] In the electromagnetic wave control element 10, as a preferred embodiment, the metasurface structure 18 acts on electromagnetic waves with a frequency of 0.1 to 0.3 THz. Therefore, the metasurface structure 18 selects a microstructure so that it can appropriately act on electromagnetic waves of this frequency, and further sets the arrangement of the microstructure, the planar shape and size of the unit cell, etc.

[0095] The metasurface structure 18 is basically composed of an arrangement of unit cells formed by one microstructure and a space around the microstructure. The metasurface structure 18 modulates the phase of an incident electromagnetic wave by utilizing the resonance of the microstructure through the arrangement of the unit cells.

[0096] Here, in the electromagnetic wave control element 10 of the present invention, the number of microstructures in one unit cell is basically one, but the present invention is not limited to this. That is, in the electromagnetic wave control element of the present invention, according to the target optical properties, the size of the microstructure, the forming material and shape, and the size of the unit cell, one unit cell can have multiple microstructures as needed. In this case, one unit cell can have different microstructures. However, in the case where one unit cell has multiple microstructures, basically, the phase modulation amount in the space where each resonator of the unit cell is located is equal.

[0097] In the electromagnetic wave controlling element 10 of the present invention, the material forming the microstructure constituting the metasurface structure 18 is not limited, and various materials used as resonators in known metasurface structures can be used.

[0098] As the material for forming the microstructure, metals and dielectrics can be exemplified. In the case of metals, copper, gold, and silver can be preferably exemplified from the viewpoint of low optical loss, etc. On the other hand, in the case of dielectrics, silicon, titanium oxide, and germanium can be preferably exemplified from the viewpoint of large refractive index and ability to perform large phase modulation, etc.

[0099] Likewise, the shape of the microstructure constituting the metasurface structure 18 is not limited, and various shapes used as resonators in known metasurface structures can be used.

[0100] As an example, in addition to a plate-like object having a square planar shape as described above, there can also be exemplified a plate-like object having a rectangular planar shape, a cross-shaped solid such as a crossed rectangular solid, a rectangular solid, a cylindrical shape, a V-shaped solid such as connecting rectangular solids at the ends as shown in Japanese Patent Gazette No. 2018-046395, a roughly H-shaped solid such as H-steel, and a roughly C-shaped solid such as a C-channel, etc.

[0101] Furthermore, as shown in Japanese Patent Application Publication No. 2018-046395, V-shaped solids and cross-shaped solids can utilize various shapes obtained by adjusting the angle formed by two rectangular parallelepipeds.

[0102] In addition, it is also possible to use the Figure 5 The three-dimensional shape of the bottom surface shown, etc.

[0103] In the super surface structure 18, only one of the microstructures may be used, or multiple microstructures may be used simultaneously. Figure 2 As shown, the same microstructures may be arranged in the same orientation, in different orientations, or in a mixture of the same orientation and different orientations.

[0104] The reflective layer 24 reflects electromagnetic waves that are incident from the alignment layer 12 side and transmit through the liquid crystal layer 14 , the adhesive layer 16 , and the metasurface structure 18 .

[0105] The reflective layer 24 is not limited, and various known sheet-shaped materials can be used as long as they can reflect the electromagnetic waves acted on by the metasurface structure 18. In the example shown in the figure, as a preferred embodiment, the metasurface structure 18 acts on electromagnetic waves with a frequency of 0.1 to 0.3 THz.

[0106] At this time, as the reflective layer 24, for example, there can be illustrated a metal layer such as copper, aluminum, gold, and silver, an inorganic conductive material such as ITO (tin-doped indium oxide), an organic conductive material such as polythiophene represented by PEDOT (poly 3,4-ethylenedioxythiophene), and graphene, etc. In addition, the inorganic conductive material, the organic conductive material, and the graphene, etc. are transparent to visible light, but function as a reflective layer for electromagnetic waves of the above frequency.

[0107] The thickness of the reflective layer 24 is not limited either, and may be appropriately set according to the material forming the reflective layer 24 so as to reflect electromagnetic waves at a desired reflectivity.

[0108] The electromagnetic wave control element of the present invention has a liquid crystal film in addition to the metasurface member including the metasurface structure 18 and the support 20 .

[0109] As described above, in the electromagnetic wave controlling element 10 shown in the figure, the liquid crystal film includes the liquid crystal layer 14 and the alignment layer 12 .

[0110] The liquid crystal layer 14 is a layer in which a liquid crystal compound is aligned and fixed.

[0111] The electromagnetic wave control element 10 of the present invention has a liquid crystal layer 14 formed by aligning and fixing liquid crystal compounds in addition to the metasurface structure 18 , and the phase of the electromagnetic wave passing through the liquid crystal layer 14 is modulated according to the refractive index of the liquid crystal layer 14 .

[0112] The electromagnetic wave control element 10 of the present invention, by having such a liquid crystal layer 14, can compensate for the interference of the phase modulation of the electromagnetic wave caused by the discreteness of the fine structure constituting the supersurface structure 18, compensate for the interference of the phase modulation of the electromagnetic wave caused by the difference in the size of the fine structure constituting the supersurface structure 18, compensate for the interference of the phase modulation of the electromagnetic wave caused by the difference in the shape of the fine structure constituting the supersurface structure 18, control the phase modulation amount of the electromagnetic wave in the electromagnetic wave control element 10 and control the reflection direction of the incident electromagnetic wave, etc.

[0113] In the present invention, the alignment of the liquid crystal compound in the liquid crystal layer 14 is not limited, and various alignments can be used.

[0114] As an example, when the liquid crystal compound is a rod-shaped liquid crystal compound, examples include a horizontal orientation in which the length direction, i.e., the optical axis originating from the liquid crystal compound, is parallel to the main surface of the liquid crystal layer 14, a vertical orientation in which the length direction is perpendicular to the thickness direction of the liquid crystal layer 14, and an orientation in which the length direction is inclined relative to the main surface of the liquid crystal layer 14.

[0115] In the case of horizontal orientation, for example, the longitudinal direction may coincide with the X direction or the Y direction, or the longitudinal direction may be oriented in a direction having an angle with respect to the X direction and the Y direction.

[0116] Furthermore, the orientation of the liquid crystal compound in the liquid crystal layer 14 may have a liquid crystal orientation pattern that changes periodically. For example, there may be exemplified a liquid crystal orientation pattern that changes in a manner of continuous rotation (rotation at a constant rotation angle) in the longitudinal direction of the above-mentioned X direction or Y direction, a liquid crystal orientation pattern that changes in a manner of discontinuous rotation (rotation at a non-constant rotation angle) in the longitudinal direction of the above-mentioned X direction or Y direction, and a liquid crystal orientation pattern in which the orientation in the X direction and the orientation in the Y direction in one direction are alternately repeated at a predetermined length (period).

[0117] Furthermore, when the microstructures constituting the super surface structure are arranged in a periodic pattern, it is also possible to preferably utilize a liquid crystal orientation pattern corresponding to the arrangement pattern of the microstructures.

[0118] For example, Figure 2 As shown, in the illustrated example of the super surface structure 18, small-sized microstructures 28a, medium-sized microstructures 28b, and large-sized microstructures 28c are repeatedly arranged in this order in the X direction. And each microstructure is arranged at the center of a square region P1 with a side length of P1.

[0119] Correspondingly, if Figure 3 As conceptually shown in FIG. 1 , a liquid crystal alignment pattern can be exemplified in which a predetermined alignment pattern is repeated using a region P2 formed by combining three regions P1 in the X direction where the fine structures 28 a , 28 b , and 28 c are arranged as one unit.

[0120] In addition, Figure 3 In order to simplify the drawings, only the support body 20, the metasurface structure 18 and the liquid crystal layer 14 are shown.

[0121] exist Figure 3 In the example shown, as an example, the region P1 is divided into three regions along the X direction, and the region P2 is divided into nine regions from Φ1 to Φ9 along the X direction. Specifically, the region P1 where the small-sized fine structures 28a are arranged is divided into regions Φ1 to Φ3, the region P1 where the medium-sized fine structures 28b are arranged is divided into regions Φ4 to Φ6, and the region P1 where the large-sized fine structures 28c are arranged is divided into regions Φ7 to Φ9.

[0122] The liquid crystal compound is horizontally aligned in the nine regions, and each region determines the angle of the length direction of the liquid crystal compound with respect to the X direction. In addition, in Φ1 to Φ9, there may be regions where the angle of the length direction of the liquid crystal compound with respect to the X direction is equal.

[0123] In this example, the liquid crystal layer 14 has a liquid crystal alignment pattern in which the region P2 composed of the nine alignment states Φ1 to Φ9 is set as one period and the one period is repeated in the X direction.

[0124] In addition, Figure 3 In the example shown, there is no limitation on dividing the area P1 into three, and the area P1 may be one area, or may be divided into two or four or more areas.

[0125] Furthermore, the number of divisions may be different in the region P1 corresponding to each microstructure.

[0126] In addition, when the liquid crystal compound is a discotic liquid crystal compound, the direction that coincides with the direction orthogonal to the disc surface becomes the optical axis derived from the liquid crystal compound. Therefore, when the liquid crystal compound is a discotic liquid crystal compound, an orientation state in which the direction of the optical axis is oriented in the same manner as the above-mentioned liquid crystal compound is exemplified.

[0127] In the electromagnetic wave controlling element 10 of the present invention, the liquid crystal layer 14 may be produced by a known method according to the alignment of the liquid crystal compound in the liquid crystal layer 14 .

[0128] Therefore, the liquid crystal compound forming the liquid crystal layer 14 is not limited, and may be a rod-like liquid crystal compound or a disc-like liquid crystal compound.

[0129] -Rod-like liquid crystal compound-

[0130] As the rod-like liquid crystal compound, preferably used are azomethines, azoxides, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolans and alkenylcyclohexylbenzonitriles.

[0131] As the rod-like liquid crystal compound, not only the low-molecular liquid crystal molecules as described above but also high-molecular liquid crystal molecules can be used.

[0132] In the liquid crystal layer 14, it is more preferable that the rod-like liquid crystal compound is polymerized and fixed in alignment. That is, the liquid crystal layer 14 is preferably a layer in which a polymerizable rod-like liquid crystal compound is polymerized and fixed.

[0133] As the polymerizable rod-like liquid crystal compound, there can be used Makromol. Chem., Vol. 190, p. 2255 (1989), Advanced Materials, Vol. 5, p. 107 (1993), Advanced Ph otonics Compounds described in Volume 2, Item 036002 (2020), U.S. Patent No. 4,683,327, U.S. Patent No. 5,622,648, U.S. Patent No. 5,770,107, International Publication No. 95 / 022,586, International Publication No. 95 / 024455, International Publication No. 97 / 000600, International Publication No. 98 / 023580, International Publication No. 98 / 052905, Japanese Patent Application No. 1-272551, Japanese Patent Application No. 6-016616, Japanese Patent Application No. 7-110469, Japanese Patent Application No. 11-080081 and Japanese Patent Application No. 2001-064627.

[0134] Furthermore, as the rod-like liquid crystal compound, for example, compounds described in JP-A-11-513019 and JP-A-2007-279688 can also be preferably used.

[0135] -Disc-like liquid crystal compounds-

[0136] As the discotic liquid crystal compound, for example, the discotic liquid crystal compounds described in JP-A-2007-108732 and JP-A-2010-244038 can be preferably used.

[0137] The liquid crystal layer 14 in which the liquid crystal compound is aligned and fixed may be formed in the same manner as a known liquid crystal layer in which the alignment of the liquid crystal compound is fixed.

[0138] For example, the alignment layer 12 for aligning a liquid crystal compound is formed by applying a composition containing a liquid crystal compound and the like, drying the composition, and polymerizing the liquid crystal compound as necessary.

[0139] In the electromagnetic wave controlling element 10 of the present invention, the thickness of the liquid crystal layer 14 is not limited and may be appropriately set according to the material forming the liquid crystal layer 14 and the target refractive index, that is, the target phase modulation amount, and the like.

[0140] The thickness of the liquid crystal layer 14 is preferably 1 to 10000 μm, more preferably 10 to 5000 μm, and even more preferably 100 to 2000 μm.

[0141] As described above, in the electromagnetic wave controlling element 10 shown in the figure, the alignment layer 12 and the liquid crystal layer 14 constitute a liquid crystal film.

[0142] As an example, the electromagnetic wave control element 10 shown in the figure is formed as a laminated film in which an orientation layer 12 is formed on the surface of a liquid crystal layer support and a liquid crystal layer 14 is formed on the surface of the orientation layer 12. Next, the liquid crystal layer 14 is made to face an adhesive layer 16 described later, and the laminated film is adhered to the adhesive layer 16. Thereafter, the liquid crystal layer support is peeled off from the laminated film, and the orientation layer 12 and the liquid crystal layer 14 are transferred to the adhesive layer 16, thereby forming a liquid crystal film.

[0143] In the electromagnetic wave control element 10 of the present invention, the orientation layer 12 for orienting the liquid crystal compound constituting the liquid crystal layer 14 can use various known orientation layers as long as they have a required transmittance to electromagnetic waves.

[0144] As the orientation layer 12, for example, there can be exemplified a friction-treated film composed of an organic compound such as a polymer, an inclined vapor-deposited film of an inorganic compound, a film having microgrooves, and a film formed by accumulating an LB (Langmuir-Blodgett) film based on the Langmuir-Blodgett method of organic compounds such as ω-tricosanoic acid, dioctadecylmethylammonium chloride and methyl stearate.

[0145] The alignment layer 12 formed by rubbing treatment can be formed by rubbing the surface of the polymer layer with paper or cloth a plurality of times in a predetermined direction.

[0146] Preferred examples of materials used for the alignment layer 12 include polyimide, polyvinyl alcohol, polymers having polymerizable groups described in Japanese Unexamined Patent Publication No. 9-152509, and materials used for forming the alignment layer 12 described in Japanese Unexamined Patent Publication Nos. 2005-97377, 2005-99228, and 2005-128503.

[0147] In the electromagnetic wave control element of the present invention, the orientation layer 12 is preferably a so-called photo-orientation layer formed by irradiating a photo-orientation material with polarized light or non-polarized light as the orientation layer 12. That is, in the electromagnetic wave control element of the present invention, the orientation layer 12 is preferably an orientation layer 12 formed by coating a composition containing a photo-orientation material on a liquid crystal layer support.

[0148] Examples of the photo-alignment material that can be used in the alignment layer 12 of the present invention include Japanese Patent Application Publication No. 2006-285197, Japanese Patent Application Publication No. 2007-076839, Japanese Patent Application Publication No. 2007-138138, Japanese Patent Application Publication No. 2007-094071, Japanese Patent Application Publication No. 2007-121721, Japanese Patent Application Publication No. 2007-140465, Japanese Patent Application Publication No. 2007-15 Azo compounds described in Japanese Patent Publication No. 6439, Japanese Patent Publication No. 2007-133184, Japanese Patent Publication No. 2009-109831, Japanese Patent No. 3883848 and Japanese Patent No. 4151746, aromatic ester compounds described in Japanese Patent Publication No. 2002-229039, and aromatic ester compounds described in Japanese Patent Publication No. 2002-265541 and Japanese Patent Publication No. 2002-317013 The photo-alignment unit-containing maleimide and / or alkenyl-substituted nadic imide compound described in Japanese Patent Nos. 4205195 and 4205198, the photo-crosslinkable silane derivatives described in Japanese Patent No. 2003-520878, Japanese Patent No. 2004-529220, and Japanese Patent No. 4162850, the photo-crosslinkable polyimide, the photo-crosslinkable polyamide, and the photo-crosslinkable ester are described in Japanese Patent No. 2003-520878, Japanese Patent No. 2004-529220, and Japanese Patent No. 4162850. Preferred examples include compounds capable of photodimerization described in JP-A-9-118717, JP-A-10-506420, JP-A-2003-505561, International Publication No. 2010 / 150748, JP-A-2013-177561, and JP-A-2014-012823, in particular cinnamate compounds, chalcone compounds, and coumarin compounds.

[0149] Among them, azo compounds, photo-crosslinkable polyimides, photo-crosslinkable polyamides, photo-crosslinkable esters, cinnamate compounds (cinnamoyl compounds), and chalcone compounds can be preferably used as the photo-alignment material.

[0150] The thickness of the alignment layer 12 is not limited, and may be appropriately set according to the material forming the alignment layer 12 so as to obtain a desired alignment function.

[0151] The thickness of the alignment layer 12 is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm.

[0152] The method for forming the alignment layer 12 is not limited, and various known methods corresponding to the material for forming the alignment layer 12 can be used.

[0153] For example, if the alignment layer 12 uses a photo-alignment material, a composition including the photo-alignment material to be the alignment layer 12 is applied to the surface of the liquid crystal layer support and dried, and then the alignment layer 12 is exposed to, for example, polarized light or non-polarized ultraviolet light.

[0154] Furthermore, in the case of forming an orientation pattern corresponding to the liquid crystal orientation pattern, an orientation layer 12 having a desired orientation pattern can be formed by repeatedly performing the following steps: masking unnecessary areas, exposing the composition to incident linear polarized light corresponding to the orientation direction of the target liquid crystal compound, changing the position of the mask and the direction of the linear polarized light according to the formed orientation pattern, and exposing the composition again.

[0155] Figure 1 The electromagnetic wave control element 10 shown is constructed by bonding a supersurface component having a support body 20 and a supersurface structure 18 with a reflective layer 24 formed on one side of the support body 20 and a liquid crystal film having an orientation layer 12 and a liquid crystal layer 14 with an adhesive layer 16 in a manner such that the supersurface structure 18 and the liquid crystal layer 14 are opposite to each other.

[0156] In the electromagnetic wave controlling element 10 , the metasurface member is thereby arranged in contact with the adhesive layer 16 as an intermediate layer, and further, the adhesive layer 16 as an intermediate layer is arranged in contact with the liquid crystal film.

[0157] The electromagnetic wave controlling element 10 of the present invention has such a structure, so that the variation in the reflectivity of electromagnetic waves within the plane is small, and as a result, an electromagnetic wave controlling element with high reflectivity is realized.

[0158] As described above, the electromagnetic wave controlling element 10 is a reflection-type electromagnetic wave controlling element that reflects electromagnetic waves incident from the orientation layer 12 side.

[0159] Specifically, the electromagnetic wave incident on the electromagnetic wave control element 10 from the orientation layer 12 side is phase-modulated by the refractive index (birefringence) possessed by the liquid crystal layer 14. The electromagnetic wave whose phase is modulated by the liquid crystal layer 14 is then phase-modulated by the resonance (resonance) based on the fine structure in the metasurface structure 18 and then reflected by the reflective layer 24. The electromagnetic wave reflected by the reflective layer 24 is phase-modulated again by the resonance based on the fine structure in the metasurface structure 18. The electromagnetic wave whose phase is modulated by the metasurface structure 18 is then phase-modulated by the refractive index possessed by the liquid crystal layer 14 and is emitted as an electromagnetic wave reflected by the electromagnetic wave control element 10.

[0160] Furthermore, the electromagnetic wave reflected by the electromagnetic wave control element 10 is not regularly reflected by the phase modulation performed by the metasurface structure 18 and the liquid crystal layer 14, but is emitted at an angle different from regular reflection. For example, when the electromagnetic wave is incident on the electromagnetic wave control element 10 from the normal direction, the electromagnetic wave is emitted in a direction having an angle with respect to the normal direction.

[0161] In such an electromagnetic wave controlling element 10 , it is important that the liquid crystal layer 14 is uniformly provided on the entire surface of the metasurface structure 18 without causing deflection or deformation of the liquid crystal layer 14 .

[0162] That is, the electromagnetic wave control element 10 using the liquid crystal layer 14 and the metasurface structure 18 controls the phase of the incident electromagnetic wave through the liquid crystal layer 14 and the metasurface structure 18 and emits the electromagnetic wave in a desired direction.

[0163] Therefore, if the positional relationship between the liquid crystal layer 14 and the metasurface structure 18 in the transmission direction of the electromagnetic wave is partially different due to the deflection of the liquid crystal layer, etc., appropriate phase control cannot be performed in this portion. As a result, a reduction in reflectivity and a deviation in the reflection direction occur locally in the plane, resulting in a deviation in the reflectivity of the electromagnetic wave in the plane.

[0164] In contrast, as described above, in the electromagnetic wave control element 10 of the present invention, the metasurface component is configured to contact the intermediate layer, and the intermediate layer is configured to contact the liquid crystal film. In the example shown in the figure, the intermediate layer is the adhesive layer 16, so the metasurface component is bonded to the adhesive layer 16, and the adhesive layer 16 is bonded to the liquid crystal film.

[0165] That is, in the electromagnetic wave control element 10 of the present invention, the positional relationship between the liquid crystal layer 14 and the metasurface structure 18 is defined by the intermediate layer, and the liquid crystal layer 14 is uniformly disposed over the entire surface without being warped relative to the metasurface structure 18 .

[0166] Therefore, according to the electromagnetic wave controlling element 10 of the present invention, the phase of the electromagnetic wave can be appropriately controlled over the entire surface in the plane direction. As a result, the electromagnetic wave can be reflected with high reflectivity while suppressing the variation in reflectivity of the electromagnetic wave within the plane.

[0167] In particular, as a preferred embodiment, Figure 1 In the electromagnetic wave controlling element 10 shown, the metasurface structure 18 is in contact with the adhesive layer 16 as an intermediate layer, and the adhesive layer 16 as an intermediate layer is in contact with the liquid crystal layer 14 , so that this effect can be more preferably obtained.

[0168] In the electromagnetic wave controlling element 10 of the present invention, the adhesive layer 16 may be a layer formed of a known adhesive as long as it has a required transmittance to electromagnetic waves.

[0169] Therefore, the adhesive that forms the adhesive layer 16 may be an adhesive, or a bonding agent, or a material having the characteristics of both an adhesive and a bonding agent. In addition, an adhesive is an adhesive that has fluidity when attached and then becomes solid. On the other hand, a bonding agent is an adhesive that is a soft solid in a gel state (rubber state) when attached and does not change the gel state afterwards.

[0170] As an adhesive, a tackiness adhesive is mentioned as an example.

[0171] Examples of the tackiness adhesive include pressure-sensitive adhesives, drying-curing adhesives, and chemical reaction adhesives.

[0172] Examples of the chemical reaction type adhesive include an active energy ray curing type adhesive.

[0173] Pressure-sensitive adhesives usually contain polymers and may also contain solvents. As polymers, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes and polyethers can be cited. Among these pressure-sensitive adhesives, pressure-sensitive adhesives containing acrylic polymers have excellent optical transparency, moderate wettability or cohesiveness, excellent adhesion, and high weather resistance or heat resistance. They are not easy to float or peel off under heating or humidification conditions, so they are preferred. As acrylic polymers, for example, it is preferred that the alkyl group of the ester part is a (meth) acrylate with an alkyl group of 1 to 20 carbon atoms such as methyl, ethyl or butyl, and a copolymer of a (meth) acrylic monomer having a functional group such as (meth) acrylic acid or hydroxyethyl (meth) acrylate. The pressure-sensitive adhesive containing such a copolymer has excellent adhesion, and even when it is removed after being attached to the transfer body, no residual glue will be generated on the transfer body, and it can be removed relatively easily, so it is preferred. The glass transition temperature of the acrylic polymer is preferably below 25°C, and more preferably below 0°C. The mass average molecular weight of the acrylic polymer is preferably 100,000 or more.

[0174] Moreover, commercially available products such as NCF-F619, NCF-F632, and NCF-F692 manufactured by LINTEC Corporation can also be preferably used as the adhesive.

[0175] The thickness of the adhesive layer 16 is not limited, and may be appropriately set according to the material forming the adhesive layer 16 so as to exhibit desired properties such as adhesive force (orientation force).

[0176] In the present invention, the adhesive layer 16 (intermediate layer) is preferably substantially thin. That is, the distance between the supersurface member and the liquid crystal film is preferably short, and the distance between the supersurface structure 18 and the liquid crystal layer 14 is particularly preferably short.

[0177] Specifically, the thickness of the adhesive layer 16 is preferably 60 μm or less, more preferably 50 μm or less, and further preferably 30 μm or less.

[0178] By setting the thickness of the adhesive layer 16 to 60 μm or less, it is possible to more appropriately suppress the variation in the reflectance of electromagnetic waves within the plane, thereby improving the reflectance of electromagnetic waves, which is preferable from such a viewpoint.

[0179] Furthermore, in the present invention, the distance between the metasurface structure 18 and the liquid crystal layer 14 is preferably 150 μm or less, more preferably 110 μm or less, and further preferably 80 μm or less.

[0180] The refractive index of the adhesive layer 16 is not limited, but is preferably close to the refractive index of the liquid crystal layer 14 .

[0181] Specifically, the refractive index of the adhesive layer 16 (intermediate layer) is preferably 1.3 to 1.7, more preferably 1.4 to 1.67, and even more preferably 1.44 to 1.60.

[0182] By setting the refractive index of the adhesive layer 16 to 1.3 to 1.7, unnecessary reflection at the interface of the adhesive layer 16 can be suppressed, and as a result, the reflectivity can be improved and stray light can be reduced, which is preferable from these viewpoints.

[0183] Figure 1 The electromagnetic wave control element 10 shown has an orientation layer 12 for orienting the liquid crystal compound on the electromagnetic wave incident surface side of the liquid crystal layer 14, but the present invention is not limited to this. That is, the electromagnetic wave control element of the present invention may not have the orientation layer 12, and the liquid crystal layer 14 may become the incident and emitting surface of the electromagnetic wave. In other words, the liquid crystal film in the electromagnetic wave control element of the present invention may be formed only by the liquid crystal layer 14.

[0184] As described above, in the manufacture of the electromagnetic wave control element 10, as an example, an alignment layer 12 is formed on the surface of a liquid crystal layer support, and a stacked film is formed on the surface of the alignment layer 12. Next, the liquid crystal layer 14 is made to face the adhesive layer 16 described later, and the stacked film is adhered to the adhesive layer 16. Thereafter, the liquid crystal layer support is peeled off from the stacked film, and the alignment layer 12 and the liquid crystal layer 14 are transferred to the adhesive layer 16, thereby forming a liquid crystal film.

[0185] At this time, the alignment layer 12 is peeled off from the laminated film together with the liquid crystal layer support. Thus, an electromagnetic wave control element can be obtained by laminating the liquid crystal layer 14, the adhesive layer 16, the metasurface structure 18, the support 20 and the reflective layer 24 in this order from the electromagnetic wave incident side.

[0186] Alternatively, the electromagnetic wave control element of the present invention may have a layer structure in which a liquid crystal layer support, an orientation layer 12, a liquid crystal layer 14, an adhesive layer 16, a metasurface structure 18, a support 20 and a reflective layer 24 are stacked in order from the incident side of the electromagnetic wave.

[0187] That is, the liquid crystal film in the electromagnetic wave controlling element of the present invention may be the above-mentioned laminated film having a three-layer structure of a liquid crystal layer support, an alignment layer 12 , and a liquid crystal layer 14 .

[0188] Therefore, in this structure, the liquid crystal layer supporting body becomes the incident and emitting surface of electromagnetic waves.

[0189] In the structure where the liquid crystal layer support body serves as the incident and emitting surfaces of electromagnetic waves, the liquid crystal layer support body is preferably formed of a material with low retardation so as not to affect the incident electromagnetic waves and the emitted electromagnetic waves.

[0190] Specifically, the liquid crystal layer support in the structure is preferably formed of low-retardation materials such as cycloolefin copolymer (COCC), triacetyl cellulose (TAC), diacetyl cellulose (DAC), methyl cellulose (MC), polyimide (PI), (meth) acrylic polymer, polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polycarbonate (PC), polyphenylene ether (PPE), polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), perfluoroethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), epoxy resin and phenolic resin.

[0191] The thickness of the liquid crystal layer support is not limited either, and may be appropriately set to a thickness capable of supporting the alignment layer 12 and the liquid crystal layer 14 according to the forming material, and is preferably 50 to 1000 μm, and more preferably 80 to 700 μm.

[0192] In addition, the structures of various liquid crystal films can also be used in various electromagnetic wave control elements shown below.

[0193] Figure 1 In the electromagnetic wave control element 10 shown, the adhesive layer 16 is used as an intermediate layer in contact with the metasurface member and the liquid crystal film, but in the electromagnetic wave control element of the present invention, an orientation layer for orienting the liquid crystal compound of the liquid crystal layer 14 can also be used as an intermediate layer.

[0194] Figure 4 An example thereof is conceptually shown in FIG. Figure 4 In the electromagnetic wave control element shown, due to multiple use with Figure 1Since the electromagnetic wave controlling element shown in the figure has the same components, in the example shown below, the same reference numerals are given to the same components, and the description will be mainly focused on the different parts.

[0195] Furthermore, the effects of the liquid crystal layer 14 and the super surface structure 18 are also the same as those described above. Figure 1 The electromagnetic wave control elements shown are the same.

[0196] Figure 4 The electromagnetic wave control element shown includes an alignment layer 26 as an intermediate layer covering a supersurface structure 18 formed on a surface of a support 20 , and includes a liquid crystal layer 14 on the side of the alignment layer 26 opposite to the supersurface structure 18 .

[0197] Therefore, in this example, the metasurface component is configured to be in contact with the alignment layer 26 as an intermediate layer, and the alignment layer 26 as an intermediate layer is configured to be in contact with the liquid crystal film. In addition, in this structure, as a preferred embodiment, the metasurface structure 18 is configured to be in contact with the alignment layer 26 as an intermediate layer, and the alignment layer 26 as an intermediate layer is configured to be in contact with the liquid crystal layer.

[0198] As a result, Figure 1 The electromagnetic wave controlling element shown can also suppress the variation in the reflectivity of electromagnetic waves within a plane, thereby improving the reflectivity of electromagnetic waves.

[0199] The alignment layer 26 as an intermediate layer is not limited, and known alignment layers such as the alignment layers exemplified in the above alignment layer 12 can be used. Among them, among the alignment layers 26 as intermediate layers, an alignment layer using a photo-alignment material (photo-alignment layer) is preferably used.

[0200] As described above, the alignment layer 12 using the photoalignment material is formed by coating a composition containing the photoalignment material, and the liquid crystal layer 14 in which the liquid crystal compound is aligned by the alignment layer is also formed by coating a composition containing the liquid crystal compound.

[0201] Therefore, by using a photo-alignment layer as the alignment layer 26 , the super-surface member and the alignment layer 26 , and the alignment layer 26 and the liquid crystal layer 14 are in close contact with each other over the entire surface.

[0202] As a result, the super surface member can be preferably arranged in contact with the intermediate layer, and the intermediate layer can be preferably arranged in contact with the liquid crystal film.

[0203] In the electromagnetic wave controlling element of the present invention described above, the intermediate layer (adhesive layer 16 , alignment layer 26 ) is in direct contact with the liquid crystal layer 14 and the metasurface structure 18 , but the present invention is not limited thereto.

[0204] That is, in the electromagnetic wave control element of the present invention, if the supersurface member including the supersurface structure is arranged in contact with the intermediate layer, and the intermediate layer is arranged in contact with the liquid crystal film including the liquid crystal layer 14, various layer structures can be used.

[0205] For example, in a structure using the alignment layer 26 as an intermediate layer, the super surface member may have an alignment layer forming film for forming the alignment layer 26 . Figure 5 An example thereof is conceptually shown in FIG.

[0206] Figure 5 The electromagnetic wave control element shown has an alignment layer forming film 32 covering the surface of the metasurface structure 18, and an alignment layer 26 as an intermediate layer is formed on the surface of the alignment layer forming film 32. That is, in this example, the metasurface component is composed of the support 20, the metasurface structure 18 and the alignment layer forming film 32.

[0207] The alignment layer forming film 32 can be any known film (sheet) as long as it has the required transmittance for electromagnetic waves and can form the alignment layer 26 on the surface. From the viewpoint of being able to be closely attached to the entire surface like the alignment layer 26, the alignment layer forming film 32 is preferably a film formed of a material that can be formed by a coating method.

[0208] Specifically, examples of the material for forming the alignment layer forming film 32 include polyvinyl alcohol (PVA), polyimide, an azo-based photo-alignment material, a cinnamoyl-based photo-alignment material, a chalcone-based photo-alignment material, and a stilbene-based photo-alignment material.

[0209] The thickness of the alignment layer forming film 32 is not limited, and may be appropriately set to a thickness capable of forming the alignment layer 26 according to the forming material and the like.

[0210] Here, as described above, the thickness of the alignment layer 26 as the intermediate layer is preferably 50 μm or less, but when the alignment layer 26 is formed on the alignment layer forming film 32, the total thickness of the alignment layer 26 and the alignment layer forming film 32 is preferably 50 μm or less. Furthermore, the total thickness of the alignment layer 26 and the alignment layer forming film 32 is more preferably 30 μm or less, and further preferably 10 μm or less.

[0211] By setting the total thickness of the alignment layer 26 and the alignment layer forming film 32 to 50 μm or less, it is preferable from the viewpoint that the variation in the reflectance of electromagnetic waves within the plane can be more appropriately suppressed, thereby improving the reflectance of electromagnetic waves.

[0212] In the above examples, the reflective layer 24 is disposed on the side of the metasurface component opposite to the intermediate layer, but the present invention is not limited thereto.

[0213] That is, in the electromagnetic wave controlling element of the present invention, the reflective layer 24 may be provided on the side of the liquid crystal film opposite to the intermediate layer. Figure 6 An example thereof is conceptually shown in FIG.

[0214] Figure 6 The electromagnetic wave control element shown has the following structure: a super surface component having a support body 20 and a super surface structure 18 and a liquid crystal film having a liquid crystal layer support body 30, an orientation layer 12 and a liquid crystal layer 14 are bonded together with an adhesive layer 16 in such a way that the support body 20 of the super surface component and the liquid crystal layer 14 of the liquid crystal film are opposite to each other.

[0215] exist Figure 6 In the electromagnetic wave controlling element shown, a reflective layer 24 is provided on the side of the liquid crystal layer supporting body 30 of the liquid crystal film opposite to the alignment layer 12 .

[0216] Therefore, in this example, the electromagnetic wave is incident from the metasurface structure 18, is phase-modulated in the metasurface structure 18 and the liquid crystal layer 14 and is incident on the reflective layer 24, is reflected by the reflective layer 24, is phase-modulated in the liquid crystal layer 14 and the metasurface structure 18, and is emitted from the metasurface structure 18 as a reflected electromagnetic wave.

[0217] Figure 7 Another example is conceptually shown in FIG.

[0218] Figure 7 The electromagnetic wave control element shown comprises: a liquid crystal film having a liquid crystal layer 14, an orientation layer 12 and a liquid crystal layer support 30; and a metasurface component having a reflective layer 24 formed on the side of the support 20 opposite to the metasurface structure 18, and having a support 20 and a metasurface structure 18.

[0219] The electromagnetic wave control element has a structure in which a liquid crystal layer support body 30 of a liquid crystal film and a metasurface structure body 18 of a metasurface member are bonded together by an adhesive layer 16 so as to face each other.

[0220] The polarization state (polarization wave state) of the electromagnetic wave that the electromagnetic wave controlling element of the present invention is used for is not limited, and may be unpolarized light, linearly polarized light, circularly polarized light, or elliptically polarized light.

[0221] When the electromagnetic wave is linearly polarized light and the microstructures are two-dimensionally arranged in the orthogonal X and Y directions, the electromagnetic wave is preferably incident so that the polarization direction of the electromagnetic wave coincides with the X or Y direction.

[0222] As mentioned above, the electromagnetic wave controlling element of the present invention has been described in detail, but the present invention is not limited to the above-mentioned examples, and various improvements and changes can be made without departing from the scope of the present invention.

[0223] Example

[0224] Hereinafter, the features of the present invention will be described in more detail with reference to examples.

[0225] In addition, the embodiment shown below is an example showing an example of the present invention. Therefore, the present invention should not be limitedly interpreted by the specific examples shown below.

[0226] [Example 1]

[0227] <Production of metasurface components>

[0228] As a support, a COP film was produced by the method described in Japanese Patent No. 4991170. The thickness of the support (COP film) was 40 μm.

[0229] Next, the prepared support was cut into 4×4 cm squares. The surface of the cut support was ultrasonically cleaned (45 kHz) and then placed in the film-forming position inside the sputtering film-forming device. After the pressure inside the device was reduced, argon gas was introduced, and Cu was sputtered on the target to form a copper layer with a thickness of 200 μm on the surface of the support.

[0230] By sequentially performing the formation of the copper layer on each side of the support, a copper layer with a thickness of 200 nm was formed on both sides.

[0231] Next, the photosensitive transfer member (negative transfer material 1) described in Japanese Patent Application Laid-Open No. 2020-204757 was released, and one cover film was peeled off from the photosensitive transfer member.

[0232] Next, the photosensitive transfer member and one surface (copper layer) of the support having copper layers formed on both sides were laminated so that the photosensitive resin layer exposed by peeling off the cover film and the copper layer were in contact with each other, thereby obtaining a laminated body. The lamination process was performed under the conditions of a roll temperature of 100° C., a linear pressure of 1.0 MPa, and a linear speed of 4.0 m / min.

[0233] Prepared with Figure 2 The photomask shown corresponds to a super-surface structure in which small, medium and large square microstructures are repeatedly arranged in the X direction and the same microstructures are arranged in the Y direction orthogonal to the X direction.

[0234] The obtained laminate was irradiated with 100 mJ / cm2 from the cover film side of the photosensitive transfer member through the photomask. 2 An ultra-high pressure mercury lamp (exposure main wavelength: 365 nm) is used to expose the photosensitive resin layer.

[0235] The length of one side of the square region P1 was set to 1041 μm.

[0236] The small-sized microstructure was a square with a side length of 400 μm, the medium-sized microstructure was a square with a side length of 820 μm, and the large-sized microstructure was a square with a side length of 935 μm.

[0237] Therefore, the photomask is formed so that the openings of this size are arranged in the X direction and the Y direction corresponding to the center of the region P1.

[0238] After the photosensitive transfer member is exposed, the photomask is removed and the cover film is peeled off from the photosensitive transfer member.

[0239] Thereafter, shower development was performed for 30 seconds using a 1.0 mass % sodium carbonate aqueous solution at a liquid temperature of 25° C., thereby forming a resist pattern composed of a photosensitive transfer member on the copper layer.

[0240] The laminated body on which the resist pattern was formed was subjected to copper etching at 23° C. for 30 seconds using a copper etching solution (Cu-02 manufactured by KANTO CHEMICAL CO., INC.).

[0241] Thereafter, the resist pattern was peeled off using propylene glycol monomethyl ether acetate, thereby forming a super surface structure.

[0242] Thus, the Figure 1 and Figure 2 The metasurface component shown is composed of a support body and a metasurface structure body, in which a reflective layer is formed on one side of the support body.

[0243] That is, the metasurface component has a metasurface structure on one surface of a support body (COP film) with a thickness of 40 μm, in which a square area P1 with a side length of 1041 μm is set as a square grid in the X direction and the Y direction, and at the center of the square area P1, a square plate-like microstructure with a thickness of 200 nm and a side length of 400 μm, a square plate-like microstructure with a thickness of 200 nm and a side length of 820 μm, and a square plate-like microstructure with a thickness of 200 nm and a side length of 935 μm are repeatedly arranged in sequence in the X direction, and the same resonators are arranged in the Y direction.

[0244] Furthermore, a copper layer serving as a reflective layer is provided on the other surface of the support (COP film).

[0245] <Production of Liquid Crystal Film>

[0246] As a liquid crystal layer support, a cellulose acylate film (thickness 60 μm, manufactured by FUJIFILM Corporation, TG60) was prepared.

[0247] The following alignment layer forming composition 1 was applied to the surface of the liquid crystal layer support using a wire bar.

[0248] The liquid crystal layer support body on which the coating film was formed was dried with hot air at 60° C. for 60 seconds and further dried with hot air at 100° C. for 120 seconds to form an alignment layer.

[0249] Next, a rubbing treatment was performed once (roller rotation speed: 1000 rpm / spacer thickness 1.8 mm, stage speed 1.8 m / min) to obtain a thin film with an alignment layer. The alignment layer had a film thickness of 100 nm.

[0250]

[0251] [Chemical formula 1]

[0252]

[0253] The following liquid crystal composition was continuously coated on the formed alignment layer using a wire bar.

[0254] The coating film was heated to 80°C on a hot plate and then irradiated with a high pressure mercury lamp at 300 mJ / cm in a nitrogen atmosphere. 2 The coating film was irradiated with ultraviolet rays having a wavelength of 365 nm at an irradiation amount to fix the alignment of the liquid crystal compound.

[0255] This liquid crystal fixing layer was applied in a stacked manner, and heated and ultraviolet-cured under the same conditions as above to prepare a laminated film having a liquid crystal layer having a film thickness of 500 μm.

[0256]

[0257] Liquid crystal compound L-1

[0258] [Chemical formula 2]

[0259]

[0260] Leveling agent T-1

[0261] [Chemical formula 3]

[0262]

[0263] <Manufacturing of components for electromagnetic wave control>

[0264] The produced metasurface member and the laminated film were bonded using a 15 μm thick adhesive layer (manufactured by LINTEC Corporation, NCF-F619, refractive index of about 1.47) serving as an intermediate layer so that the metasurface structure and the liquid crystal layer faced each other.

[0265] Then, the liquid crystal layer support (cellulose acylate film) was peeled off from the laminated film to prepare Figure 1 The electromagnetic wave control element shown.

[0266] [Example 2]

[0267] In the preparation of the laminated film of Example 1, a laminated film was prepared in the same manner as in Example 1, except that the following composition 2 for forming an alignment layer was used instead of the composition 1 for forming an alignment layer.

[0268]

[0269] [Chemical formula 4]

[0270]

[0271] Using this laminated film and the same supersurface member as in Example 1, the liquid crystal layer was made to face the supersurface structure, and the laminated film and the supersurface member were adhered in the same manner as in Example 1.

[0272] Then, the liquid crystal layer support and the alignment layer were peeled off from the laminated film, and the surface of the laminated film was free of the alignment layer. Figure 1 The electromagnetic wave control element shown.

[0273] In addition, the size of the microstructure is optimized according to the structure of the element for electromagnetic wave control.

[0274] Furthermore, unless otherwise specified, similarly to Example 1, a reflective layer is provided on the surface of the support body of the metasurface component on the opposite side to the metasurface structure.

[0275] The above points are also applicable to other examples.

[0276] [Example 3]

[0277] A film was prepared in the same manner as in Example 1 except that a UV curable adhesive (manufactured by TOAGOSEI CO., LTD., ARON IX UVX-6282, refractive index of about 1.48) was used as an intermediate layer instead of the 15 μm thick adhesive layer (manufactured by LINTEC Corporation, NCF-F619). Figure 1 The electromagnetic wave control element shown.

[0278] The thickness of the adhesive layer was 5 μm.

[0279] [Example 4]

[0280] A film was prepared in the same manner as in Example 1 except that two 30 μm thick adhesive layers (manufactured by LINTEC Corporation, NCF-F619, with a refractive index of about 1.47) were used as the intermediate layer instead of the 15 μm thick adhesive layer (manufactured by LINTEC Corporation, NCF-F619). Figure 1 The electromagnetic wave control element shown.

[0281] Therefore, in this example, the thickness of the adhesive layer (intermediate layer) is 60 μm.

[0282] [Example 5]

[0283] A COP film was prepared as a liquid crystal layer support by the method described in Japanese Patent No. 4991170. The thickness of the liquid crystal layer support was 40 μm.

[0284] An alignment layer was formed on the surface of the liquid crystal layer support in the same manner as in Example 1, and a liquid crystal layer was formed on the alignment layer in the same manner as in Example 1, thereby producing a laminated film.

[0285] The laminated film was used as a liquid crystal film, and the liquid crystal film and the same super surface component as in Example 1 were glued in a manner such that the liquid crystal layer support body (COP film) was opposite to the super surface structure body and in the same manner as in Example 1, thereby producing a Figure 7 The electromagnetic wave control element shown.

[0286] [Example 6]

[0287] To 1 part by mass of the photo-alignment material E-1 having the following structure were added 41.6 parts by mass of butoxyethanol, 41.6 parts by mass of dipropylene glycol monomethyl ester and 15.8 parts by mass of pure water, and the obtained solution was pressure filtered using a 0.45 μm membrane filter to prepare a photo-alignment layer coating liquid.

[0288] [Chemical formula 5]

[0289]

[0290] On the surface of the supersurface structure of the same supersurface component as Example 1, the above-mentioned orientation layer forming composition 1 is applied in a manner to a film thickness of 500 nm, dried with hot air at 60°C for 60 seconds, and then dried with hot air at 100°C for 120 seconds, thereby forming an orientation layer forming film.

[0291] Next, the prepared photo-alignment layer coating liquid was applied to the alignment layer-forming film and dried at 60° C. for 1 minute. The obtained coating film (film thickness 50 nm) was irradiated with linearly polarized ultraviolet light (illuminance 4.5 mW / cm 2 , cumulative irradiation 300mJ / cm 2 ) is formed as an intermediate layer with an orientation limiting force in the horizontal direction (photo-orientation layer, with a refractive index of about 1.52).

[0292] A liquid crystal layer with a thickness of 500 μm was formed on the surface of the formed alignment layer in the same manner as in Example 1, thereby producing Figure 5 The electromagnetic wave control element shown.

[0293] [Example 7]

[0294] On the surface of the supersurface structure of the same supersurface member as in Example 1, the following alignment layer forming composition 3 was applied so as to have a film thickness of 500 nm.

[0295]

[0296] [Chemical formula 6]

[0297]

[0298] [Chemical formula 7]

[0299]

[0300] [Chemical formula 8]

[0301]

[0302] The alignment layer forming composition 3 was dried at 100° C. The dried coating film was irradiated with polarized ultraviolet light (10 mJ / cm 2 , using an ultra-high pressure mercury lamp), an orientation layer (photo-orientation layer, with a refractive index of about 1.51) having an orientation limiting force in the horizontal direction is formed as an intermediate layer.

[0303] A liquid crystal layer with a thickness of 500 μm was formed on the surface of the formed alignment layer in the same manner as in Example 1, thereby producing Figure 4 The electromagnetic wave control element shown.

[0304] [Example 8]

[0305] A COP film was prepared as a liquid crystal layer support by the method described in Japanese Patent No. 4991170. The thickness of the liquid crystal layer support was 40 μm.

[0306] An alignment layer was formed on the surface of the liquid crystal layer support in the same manner as in Example 1, and a liquid crystal layer was formed on the alignment layer in the same manner as in Example 1, thereby producing a laminated film.

[0307] The stacked film is used as a liquid crystal film, and the liquid crystal film and the same super surface component as in Example 1 are glued in a manner such that the liquid crystal layer is opposite to the super surface structure and in the same manner as in Example 1, and a liquid crystal layer support (COP film) is provided on the surface. In addition, Figure 1 The same electromagnetic wave control element.

[0308] [Example 9]

[0309] In Example 1, the liquid crystal layer support (cellulose acylate film) was not peeled off from the laminated film, and the laminated film was used as a liquid crystal film as an electromagnetic wave control element.

[0310] [Example 10]

[0311] As a liquid crystal layer support, a cellulose acylate film (thickness 60 μm, manufactured by FUJIFILM Corporation, TG60) was prepared.

[0312] The alignment layer forming composition 1 was applied to the surface of the liquid crystal layer support using a wire bar.

[0313] The liquid crystal layer support body on which the coating film was formed was dried with hot air at 60° C. for 60 seconds and further dried with hot air at 100° C. for 120 seconds to form a PVA film. The thickness of the PVA film was 500 nm.

[0314] The photo-alignment layer coating liquid used in Example 6 was applied to the surface of the PVA film and dried at 60° C. for 1 minute to form a photo-alignment layer. The thickness of the photo-alignment layer was 50 nm.

[0315] The produced laminate having a photo-alignment layer was cut into a size of 4×4 cm.

[0316] On the other hand, a stripe mask was prepared in which a transmissive portion with a width of 347 μm and a light shielding portion with a width of 2776 μm were alternately formed. In this mask, the arrangement direction of the stripes corresponded to the X direction of the metasurface structure, and the length direction of the stripes corresponded to the Y direction of the metasurface structure.

[0317] The photo-alignment layer was covered by a mask in such a way that the end of the transmissive portion in the width direction was consistent with one end of the photo-alignment layer and the transmissive portion was located in the plane of the photo-alignment layer. Next, a UV exposure device was used to irradiate the photo-alignment layer with UV rays as linearly polarized light using a wire grid polarizer (proflux PPL02 manufactured by MOXTEK, Inc.) set in such a way that the absorption axis angle was 0° (= region Φ1). The illuminance of the UV rays was 4.5 mW / cm 2 The cumulative exposure is 300mJ / cm 2 .

[0318] In addition, the angle of the absorption axis refers to the angle relative to the width direction of the stripe, with the clockwise direction being positive. That is, when the angle of the absorption axis is 0°, it means that the angle of the absorption axis is consistent with the width direction (X direction) of the stripe. And, when the angle of the absorption axis is 90°, it means that the angle of the absorption axis is consistent with the length direction (Y direction) of the stripe.

[0319] Next, the mask was moved 347 μm in the width direction of the stripes, the wire grid polarizer was rotated so that the angle of the absorption axis became 16° (= region Φ2), and the photo-alignment layer was irradiated with linearly polarized ultraviolet light. Next, the mask was moved 347 μm in the width direction of the stripes, the wire grid polarizer was rotated so that the angle of the absorption axis became 86° (= region Φ3), and the photo-alignment layer was irradiated with linearly polarized ultraviolet light.

[0320] By changing the angle of the absorption axis of the wire grid polarizer, the mask was moved and the ultraviolet irradiation to the photo-alignment layer was performed to regions Φ4, Φ5, ..., Φ9. Thus, a photo-alignment layer having a stripe-shaped alignment pattern with a width of 347 μm and in which regions Φ1 to Φ9 with varying alignment direction angles were repeated was produced.

[0321] In addition, the angles of the absorption axis of the wire grid polarizer are set to 0° in region Φ1, 16° in region Φ2, 86° in region Φ3, 86° in region Φ4, 0° in region Φ5, 6° in region Φ6, 68° in region Φ7, 29° in region Φ8, and 4° in region Φ9.

[0322] A liquid crystal layer having a thickness of 500 μm was formed on the photo-alignment layer thus produced in the same manner as in Example 1, thereby producing a laminated film.

[0323] The angle of the absorption axis of the wire grid polarizer when forming the optical alignment layer is as described above. Therefore, the formed liquid crystal layer has a stripe shape with a width of 347 μm and the angle of the optical axis of the liquid crystal compound in the stripe repeats the liquid crystal alignment pattern of region Φ1 (0°), region Φ2 (16°), region Φ3 (86°), region Φ4 (86°), region Φ5 (0°), region Φ6 (6°), region Φ7 (68°), region Φ8 (29°) and region Φ9 (4°) in the arrangement direction of the stripe.

[0324] Then, using AxoScan (manufactured by Axometrics), it was confirmed that the direction of the optical axis (slow axis) of the liquid crystal compound in the stripes was at the above angle.

[0325] The same supersurface member and the produced laminated film as in Example 1 were bonded in the same manner as in Example 1 so that the supersurface structure and the liquid crystal layer faced each other. During bonding, the X and Y directions of the supersurface structure and the liquid crystal layer were aligned.

[0326] Furthermore, the liquid crystal layer support (cellulose acylate film), the PVA film and the photo-alignment layer were peeled off from the laminated film, and no alignment layer was present on the surface. Figure 1 The same electromagnetic wave control element.

[0327] [Example 11]

[0328] In the same manner as in Example 6, an alignment layer forming film was formed on the surface of the supersurface structure of the supersurface component, and an alignment layer (photo-alignment layer) was formed on the surface of the alignment layer forming film.

[0329] The alignment layer was exposed to linearly polarized ultraviolet light in the same manner as in Example 10, thereby forming a stripe-shaped alignment pattern.

[0330] By forming a liquid crystal layer on the alignment layer having the alignment pattern in the same manner as in Example 1, a liquid crystal layer having the same striped liquid crystal alignment pattern as in Example 10 was formed, thereby producing a liquid crystal layer having the same striped liquid crystal alignment pattern as in Example 10. Figure 5 The same electromagnetic wave control element.

[0331] [Example 12]

[0332] In the formation of the metasurface component of Example 1, a copper layer was formed only on one side of the support (COP film), and a metasurface structure was formed in the same manner as in Example 1 using the copper layer, thereby producing a metasurface component.

[0333] On the other hand, as a liquid crystal layer support, a similar COP film was prepared, and a copper layer was formed on one surface in the same manner.

[0334] The alignment layer forming composition 3 used in Example 7 was applied to the surface of the liquid crystal layer support body where the copper layer was not formed to a film thickness of 500 nm and dried at 100° C. The dried coating film was irradiated with polarized ultraviolet light (10 mJ / cm 2 , using an ultra-high pressure mercury lamp), an alignment layer (photo-alignment layer) having an alignment restricting force in the horizontal direction is formed.

[0335] A liquid crystal layer having a thickness of 500 μm was formed on the surface of the formed alignment layer in the same manner as in Example 1, thereby producing a laminated film having a reflective layer on one side of a liquid crystal layer support.

[0336] The prepared laminated film was used as a liquid crystal film, and the prepared super surface component and the liquid crystal film were adhered with an adhesive (manufactured by LINTEC Corporation, NCF-F619) having a thickness of 15 μm as an intermediate layer in such a manner that the support body and the liquid crystal layer were opposite to each other, thereby preparing a Figure 6 The same electromagnetic wave control element.

[0337] [Comparative Example 1]

[0338] The same liquid crystal film and metasurface member as those in Example 1 were stacked without using an adhesive so that the liquid crystal layer and the metasurface structure faced each other, thereby producing an electromagnetic wave control element.

[0339] [evaluate]

[0340] <Reflectivity measurement>

[0341] The reflectance and reflection variation of the produced electromagnetic wave controlling element were measured by the following method.

[0342] A two-dimensional Sub-THz imaging camera (Tera-1024, manufactured by Terasense) was used to capture the diffraction reflection at the designed angle (73.7°) when light was incident from the normal direction of the electromagnetic wave control element being manufactured and reflected using an Impatt Diode (manufactured by Terasense) with a central wavelength of 100 GHz as the light source.

[0343] The integrated value of the brightness of all pixels of the imaging camera is taken as the reflection intensity in that direction.

[0344] The reflection intensities in the -1st order (-73.7°), 0th order (regular reflection, 0°), and +1st order (73.7°) directions were measured, and these were designated as P-1, P0, and P1, respectively.

[0345] The reflectance ratio (P1 / (P-1+P0+P1) in the designed direction (+1st order, 73.7°) is defined as reflectance.

[0346] Then, 10 locations of 4 cm square in the plane of the electromagnetic wave controlling element were measured by the above method, and the standard deviation of the measurement results was taken as the deviation of the reflectance.

[0347] The evaluation criteria are as follows.

[0348] <<Reflectivity>>

[0349] A: Reflectivity is more than 80%

[0350] B: Reflectivity is 60% or more and less than 80%

[0351] C: Reflectivity is 50% or more and less than 60%

[0352] D: Reflectivity less than 50%

[0353] <<Deviation>>

[0354] A: Less than 20%

[0355] B: 20% or more

[0356] The results are shown in Table 1 below.

[0357] [Table 1]

[0358]

[0359] As shown in the above table, the electromagnetic wave control element of the present invention having an intermediate layer configured in contact with a liquid crystal film having a liquid crystal layer and a supersurface component having a supersurface structure has less deviation in the surface direction of electromagnetic wave reflection and better reflectivity than the comparison example without an intermediate layer.

[0360] In particular, as shown in Example 1 (adhesive layer 15 μm) and Example 4 (adhesive layer 60 μm), by setting the thickness of the intermediate layer to 50 μm or less, a more preferred reflectivity can be obtained. Furthermore, as shown in Example 10 and Example 11, by setting the liquid crystal layer to a liquid crystal layer having a liquid crystal orientation pattern, a further preferred reflectivity can be obtained.

[0361] From the above results, the effects of the present invention are obvious.

[0362] Industrial Applicability

[0363] The present invention can be preferably used in a reflector for electromagnetic waves, a beam steering device, and the like.

[0364] Explanation of symbols

[0365] 10-electromagnetic wave control element, 12-orientation layer, 14, 104-liquid crystal layer, 16-adhesive layer, 18, 100-super surface structure, 20-support body, 24-reflection layer, 28a, 28b, 28c-microstructure, 30-liquid crystal layer support body, 32-orientation layer forming film, LC-liquid crystal compound.

Claims

1. An electromagnetic wave control element, comprising: A metasurface component, comprising a metasurface structure composed of a plurality of microstructures; an intermediate layer, configured to contact the metasurface component; and a liquid crystal film disposed in contact with the intermediate layer and including a liquid crystal layer in which the orientation of the liquid crystal compound is fixed, And the intermediate layer is an adhesive layer or an orientation layer.

2. The electromagnetic wave control element according to claim 1, wherein: The metasurface structure acts on electromagnetic waves with a frequency of 0.1 to 0.3 THz.

3. The electromagnetic wave control element according to claim 1 or 2, wherein: The thickness of the intermediate layer is 50 μm or less.

4. The electromagnetic wave control element according to claim 1 or 2, wherein: A reflective layer is provided on a side of the metasurface component opposite to the intermediate layer or a side of the liquid crystal film opposite to the intermediate layer.

5. The electromagnetic wave control element according to claim 1 or 2, wherein: The intermediate layer contacts the liquid crystal layer.

6. The electromagnetic wave control element according to claim 1 or 2, wherein: The intermediate layer is in contact with the supersurface structure.

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