Selective Wavelength Reflector

Abstract

To provide a selected wavelength reflector which has high transmittance at a wavelength which is not a wavelength for reflection and can optimize a selected wavelength highly accurately.SOLUTION: The present invention is formed in such a manner that a plurality of unit patterns 13 each having at least one metal structure 12 is regularly arranged vertically and horizontally along a surface of the base body 11 in the surface of a translucent base body 11. The unit pattern 13 is shaped so that the metal structure 12 is in the shape of + when is seen from a vertical direction with respect to the surface of the base body 11. When a width of a vertical line and a horizontal line of the + shape is denoted by w(nm) and a length of the vertical line and the horizontal line is denoted by l(nm), and a length of one side of the unit pattern 13 is denoted by Λ(nm), relations of 240≤l≤370, 30≤w≤90, and 360≤Λ≤450 are satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to selective wavelength reflectors. [Background technology]

[0002] Conventionally, heat ray shielding materials that reflect infrared rays have been developed to prevent the penetration of heat rays through windows of automobiles or buildings, etc. Examples of such heat ray shielding materials include a metal particle-containing layer that contains at least one type of metal particles, in which the metal particles are approximately hexagonal or approximately disc-shaped flat metal particles at 60% or more by number, and the main planes of the flat metal particles are planarly oriented within a range of 0° to ±30° relative to one surface of the metal particle-containing layer (see, for example, Patent Document 1).

[0003] A method has been developed for forming an array of submicron-scale patterns on the surface of glass for optical purposes such as light reflection (see, for example, Patent Document 2), but the pattern is an array and does not have a planar spread. Also, a transparent sheet has been developed in which a transparent pattern having infrared reflectivity and regularity is printed on the surface of a transparent substrate (see, for example, Patent Document 3), but this is used by attaching it to the front of a display and is not intended for natural light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-118347 A [Patent Document 2] Special Publication No. 2009-517310 [Patent Document 3] JP 2008-26958 A Summary of the Invention [Problem to be solved by the invention]

[0005] The heat ray shielding material described in Patent Document 1 has excellent reflectance at selected wavelengths such as infrared rays, but has the problem that the transmittance at other wavelengths is reduced because the metal particles are randomly arranged. In addition, because the metal particles are randomly arranged, it is difficult to accurately select the wavelengths to be reflected and transmitted, that is, to optimize the selected wavelengths.

[0006] The present invention has been made with attention to such problems, and aims to provide a selective wavelength reflector that has high transmittance at wavelengths other than the wavelength to be reflected and can optimize the selected wavelength with high precision. [Means for solving the problem]

[0007] In order to achieve the above object, the selective wavelength reflector of the present invention is formed by arranging, on a surface of a light-transmitting substrate, a plurality of unit patterns each having one or more metallic structures, regularly and vertically and horizontally along the surface of the substrate, and the metallic structures of the unit patterns have a + shape when viewed from a direction perpendicular to the surface of the substrate, and when the width of the vertical and horizontal lines of the + shape is w (nm), the length of the vertical and horizontal lines is l (nm), and the length of one side of the unit pattern is Λ (nm), 240≦l≦370, 30≦w≦90, and 360≦Λ≦450, and More than 900nm It is characterized in that the maximum reflectance of light having a wavelength of 40% or more and the maximum transmittance of light having a wavelength of 350 nm to 780 nm is 50% or more.

[0008] The selective wavelength reflector according to the present invention has excellent wavelength selectivity, since it can reflect or transmit any wavelength by adjusting the shape and size of the metallic structures of the unit pattern. In addition, by finely adjusting the shape and size of the metallic structures, it is possible to increase the reflectance of light of a selected wavelength and increase the transmittance of wavelengths other than the selected wavelength. In addition, since such unit patterns are regularly arranged, it is possible to optimize the selected wavelength with higher accuracy than when they are arranged randomly.

[0009] In this way, the selective wavelength reflector according to the present invention can be optimally designed to reflect or transmit light of a desired wavelength based on the concept of metamaterials. The selective wavelength reflector according to the present invention can be manufactured using, for example, semiconductor microfabrication technology or nanoimprint technology, and even large-area selective wavelength reflectors can be manufactured at low cost.

[0010] In the selective wavelength reflector according to the present invention, the substrate may be made of any material and shape as long as it is translucent, and is made of, for example, translucent glass or plastic. The selective wavelength reflector according to the present invention can be used, for example, as windows for buildings and automobiles. In addition, for example, by designing it to reflect light in the ultraviolet region, it can be used as an ultraviolet cut filter for displays of mobile phones, personal computers, televisions, etc., and by designing it to be difficult for light from oblique directions to pass through, it can be used as an anti-peeping filter for displays of mobile phones, personal computers, televisions, etc. In addition, in the selective wavelength reflector according to the present invention, it is preferable that the unit patterns are arranged so as to be in contact with adjacent unit patterns.

[0011] The selective wavelength reflector according to the present invention may be configured to selectively reflect wavelengths of 780 nm to 1100 nm in the near infrared region, while at the same time having high transmittance for visible light with wavelengths of 350 nm to 780 nm. In this case, the amount of reflected energy of light with wavelengths of 780 nm to 1400 nm is 8.0 W / m 2 More than 10.0 W / m is preferable. 2 More preferably, it is 15.0 W / m or more. 2 It is more preferable that the reflected energy of light having a wavelength of 780 nm to 2500 nm is 9.0 W / m 2 More than 10.0 W / m is preferable. 2 More preferably, it is 20.0 W / m or more. 2Here, the amount of reflected light energy is the integrated value of the product of the energy of sunlight with AM (air mass) 1.5 and the reflectance of the selective wavelength reflector according to the present invention for each wavelength in the target wavelength range. I do. Well In addition, the maximum transmittance of light having a wavelength of 350 nm to 780 nm is preferably 50% or more, and more preferably 70% or more. In this case, it can be used as a near-infrared reflection filter. For example, when used as windows for buildings or automobiles, it can prevent the temperature inside a building or automobile from increasing due to sunlight in summer, and can reduce the power consumption of air conditioners, thereby contributing to power saving and energy saving.

[0012] The selective wavelength reflector according to the present invention may be configured to selectively reflect wavelengths of 350 nm to 780 nm in the visible light region and at the same time have high transmittance for near infrared rays with wavelengths of 780 nm to 1100 nm. In this case, it is preferable that the maximum transmittance of light with wavelengths of 780 nm to 1100 nm is 35% or more and the minimum transmittance of light with wavelengths of 350 nm to 780 nm is 5% or less. In this case, it can be used as a near infrared transmission filter. For example, when used as a window for a building or factory, it can reflect visible light from indoor lighting into the room and efficiently discharge heat trapped in the room to the outside.

[0013] In the selective wavelength reflector according to the present invention, the + shapes of the metal structures may be connected to adjacent unit patterns to form a lattice shape, or adjacent unit patterns may not be connected to each other and each unit pattern may be independent. When the metal structures form a lattice shape, the metal structures can be heated by passing electricity through them, and fog, frost, ice, etc., adhering to windows, etc. can be removed.

[0014] In the selective wavelength reflector according to the present invention, the length and width of the metallic structures in the unit pattern along the surface of the substrate and the height from the surface of the substrate are preferably 10 nm to 650 nm. In this case, the selective wavelength reflector can be configured to selectively transmit or reflect wavelengths in the near infrared region and the visible light region.

[0015] In the selective wavelength reflector according to the present invention, the metal structure may be made of gold, silver, copper or aluminum. In this case, the reflectance of the wavelength to be reflected can be effectively increased while the transmittance of the wavelength can be effectively decreased. Also, the transmittance of the wavelength to be transmitted can be effectively increased while the reflectance of the wavelength can be effectively decreased.

[0016] In the selective wavelength reflector according to the present invention, the substrate may be plate-shaped, and a plurality of reflective layers each consisting of the substrate and the unit pattern may be laminated. In this case, the reflectance of a desired wavelength can be increased by increasing the number of layers. The selective wavelength reflector according to the present invention may have a film made of ITO (indium tin oxide) on the front or back side of the substrate. In this case, the reflectance can be increased from the near infrared region to the infrared region by configuring the unit pattern to selectively reflect wavelengths in the near infrared region. The substrate may have a light-transmitting covering material to cover the surface of the substrate and the metal structure, or may have a light-transmitting covering material to cover only the metal structure. Effect of the Invention

[0017] According to the present invention, it is possible to provide a selective wavelength reflector that has high transmittance at wavelengths other than the wavelength to be reflected and that can optimize the selected wavelength with high precision. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view showing an example of a selective wavelength reflector according to an embodiment of the present invention. [Diagram 2]FIG. 11 is a plan view showing modified examples of a selective wavelength reflector according to an embodiment of the present invention, in which the metallic structures are (a) modified in a shape having lattice-like holes, (b) modified in a circular shape, (c) modified in a + shape, (d) modified in a triangular shape arranged in a first pattern, (e) modified in a triangular shape arranged in a second pattern, and (f) modified in a plurality of different sized circular shapes. [Diagram 3] 1(a) to 1(f) are cross-sectional views showing an example of a method for manufacturing a selective wavelength reflector according to an embodiment of the present invention. [Figure 4] FIG. 1 shows a unit pattern of a metal structure having a shape with a +-shaped hole, (a) a plan view of the unit pattern, (b) a cross-sectional view of the same, (c) a plan view of the unit pattern of a metal structure having a + shape, and (d) a cross-sectional view of the same, used in simulating the cross-structure of a selective wavelength reflector according to an embodiment of the present invention. [Diagram 5] 1 is a graph showing the relationship between the wavelength of light and the reflectance and transmittance, illustrating the results of Example 1 (a structure in which the metal structure is made of gold and forms a +-shaped hole) of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention. [Figure 6] 1A and 1B show the results of Example 2 (the metal structure is made of gold and forms a +-shaped hole) of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and the transmittance when l is changed, and (b) is a graph showing the relationship between the wavelength of light and the transmittance when w is changed. [Figure 7] FIG. 11 shows the results of Example 3 (the metal structure is made of gold and forms a + shape) of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance when h is changed, and (b) is a graph showing the relationship between the wavelength of light and transmittance. [Figure 8] FIG. 11 shows the results of Example 4 (the metal structure is made of gold and forms a + shape) of a simulation of a cross structure of a selected wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance when θ is changed, and (b) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the figures indicate the values ​​of θ). [Figure 9] FIG. 11 shows the results of Example 5 (the metal structure is made of silver and has a + shape) of a simulation of a cross structure of a selected wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance when θ is changed, and (b) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the figures indicate the values ​​of θ). [Figure 10] FIG. 11 shows the results of Example 6 (the metal structure is made of aluminum and has a + shape) of a simulation of a cross structure of a selected wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance when θ is changed, and (b) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the figures indicate the values ​​of θ). [Figure 11] FIG. 17 shows the results of Example 7 (where the metal structure is made of aluminum and forms a + shape) of a simulation of a cross structure of a selected wavelength reflector according to an embodiment of the present invention, for a structure larger in size than that shown in FIG. 10 , where (a) is a graph showing the relationship between the wavelength of light and reflectance, and (b) is a graph showing the relationship between the wavelength of light and transmittance when θ is changed (the numbers in the figures indicate the value of θ). [Figure 12] FIG. 13 shows the results of Example 8 (the metal structure is made of gold and forms a + shape) of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance, and (b) is a graph showing the relationship between the wavelength of light and transmittance when the size of the structure (parameter k) is changed. [Figure 13] FIG. 13 shows the results of Example 8 (the metal structure is made of gold and forms a + shape) of a simulation of a cross structure of a selected wavelength reflector according to an embodiment of the present invention, in which (a) is a graph showing the relationship between the wavelength of light and reflectance, and (b) is a graph showing the relationship between the wavelength of light and transmittance when the size of the structure (parameter p) is changed. [Figure 14]FIG. 9 is a cross-sectional view showing a unit pattern for Example 9 (where the metal structure is made of gold and forms a + shape) of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention, (a) a cross-sectional view showing a unit pattern for two layers, (b) a graph showing the relationship between the wavelength of light and the reflectance for one layer and two layers, and (c) a graph showing the relationship between the wavelength of light and the transmittance for one layer and two layers. [Figure 15] FIG. 10 is a diagram showing a cross structure simulation example 10 of a selective wavelength reflector according to an embodiment of the present invention (the metallic structures are made of gold and have a +-shaped structure, with four structures formed in a unit pattern with two rows and two columns, and there are two sizes). (a) is a plan view showing the unit pattern, (b) is a graph showing the relationship between the wavelength of light and reflectance, showing the results of a simulation when θ is changed, and (c) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the diagram indicate the value of θ). [Figure 16] FIG. 17 shows the results of a simulation of Example 11 of a cross structure simulation of a selective wavelength reflector according to an embodiment of the present invention (the metal structures are made of gold and have a +-shaped structure, four of which are formed in a unit pattern with two rows and two columns, and there are two sizes) for a structure larger than that shown in FIG. 15, where (a) is a graph showing the relationship between the wavelength of light and the reflectance, and (b) is a graph showing the relationship between the wavelength of light and the transmittance (the numbers in the figures indicate the values ​​of Λ). [Figure 17] FIG. 12 shows the results of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention (the metal structures are made of gold and have a +-shaped structure, with four structures formed in a unit pattern with two rows and two columns, and there are two sizes) for a structure larger than that shown in FIG. 15, where (a) is a graph showing the relationship between the wavelength of light and reflectance, and (b) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the figures indicate the values ​​of θ). [Figure 18]FIG. 13 shows the results of a simulation of Example 13 of a cross structure of a selective wavelength reflector according to an embodiment of the present invention (the metal structures are made of gold and have a + shape, four structures are formed in a unit pattern with two rows and two columns, and there are two sizes) for a structure larger than that shown in FIG. 17, where (a) is a graph showing the relationship between the wavelength of light and reflectance, and (b) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the figures indicate the values ​​of θ). [Figure 19] 17 is a graph showing the relationship between the wavelength of light and the reflectance and transmittance, showing the results of a simulation of Example 14 of a cross structure simulation of a selective wavelength reflector according to an embodiment of the present invention (the metal structures are made of silver, have a +-shaped structure, four are formed in a unit pattern with two rows and two columns, and there are two sizes). The graph shows the relationship between the wavelength of light and the reflectance and transmittance, showing the results of a simulation of a structure of the same size as that shown in FIG. [Figure 20] FIG. 15 shows the results of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention (the metal structure is made of gold, has a +-shaped structure, and is formed in a unit pattern of four structures with two rows and two columns, and there are two sizes of these structures), in which a Ti film for adhesion is provided between the metal structure and the base, and the thickness of the Ti film is changed. (a) is a graph showing the relationship between the wavelength of light and the reflectance, and (b) is a graph showing the relationship between the wavelength of light and the transmittance (the numbers in the figures indicate the thickness of the Ti film). [Figure 21] FIG. 15 shows the results of a simulation of a cross structure of a selective wavelength reflector according to an embodiment of the present invention (the metal structure is made of gold and has a +-shaped structure, with four structures formed in a unit pattern with two rows and two columns, and there are two sizes) in which a Cr film for adhesion is provided between the metal structure and the base, and the thickness of the Cr film is changed. (a) is a graph showing the relationship between the wavelength of light and the reflectance, and (b) is a graph showing the relationship between the wavelength of light and the transmittance (the numbers in the figures indicate the thickness of the Cr film). [Figure 22]FIG. 16 is a diagram showing a cross structure simulation example 16 of a selective wavelength reflector according to an embodiment of the present invention (the metallic structures are made of gold and have a +-shaped structure, with nine structures of three rows and three columns formed in the unit pattern, and there are three different sizes); (a) is a plan view showing the unit pattern, (b) is a graph showing the relationship between the wavelength of light and reflectance, showing the results of a simulation when θ is changed, and (c) is a graph showing the relationship between the wavelength of light and transmittance (the numbers in the diagram indicate the value of θ). [Diagram 23] FIG. 22 shows the results of a simulation of the cross structure of a selective wavelength reflector according to an embodiment of the present invention, with one, two (FIG. 15), and three (FIG. 22) types of metal structure sizes, and with θ=0°, (a) a graph showing the relationship between the wavelength of light and the reflectance, and (b) a graph showing the relationship between the wavelength of light and the transmittance. [Figure 24] FIG. 13 is a graph showing the relationship between the wavelength of light and the reflectance and transmittance when t is changed, showing the results of Example 17 (a lattice-shaped structure in which the metal structure is made of gold) of a simulation of a mesh structure of an example of a selective wavelength reflector according to an embodiment of the present invention shown in FIG. [Diagram 25] 13 is a graph showing the relationship between the wavelength of light and the reflectance and transmittance when a and g are changed, showing the results of Example 18 (the metal structure is made of gold and has a lattice-like structure) of a simulation of a mesh structure of a selective wavelength reflector according to an embodiment of the present invention. [Figure 26] 13 is a graph showing the relationship between the wavelength of light and the reflectance and transmittance, illustrating the results of Example 19 (a lattice-like structure in which the metal structures are made of gold, silver, and aluminum) of a simulation of a mesh structure of a selective wavelength reflector according to an embodiment of the present invention. [Figure 27] FIG. 1A is a plan view of a selective wavelength reflector according to an embodiment of the present invention, in which four different patterns of metal structures (+ shaped and made of aluminum) are regularly arranged on the surface of a substrate, and FIG. 1B is an enlarged plan view of a portion of the second region from the left shown in FIG. [Figure 28]28 is a graph showing measurement results (measured values) and simulation results (calculated values) of reflectance and transmittance for the selective wavelength reflector shown in FIG. 27, in which the metal structures have a pattern of (a) (w, l) = (80 nm, 360 nm) and (b) (w, l) = (60 nm, 340 nm). [Figure 29] 28 is a graph showing the measurement results of reflectance and transmittance for four patterns of metal structures of the selective wavelength reflector shown in FIG. 27. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 29 show selective wavelength reflectors according to embodiments of the present invention. As shown in FIGS. 1 and 2, the selective wavelength reflector 10 has a base body 11 and a structure 12 made of metal.

[0020] The substrate 11 is made of a light-transmitting material such as glass, plastic, etc. In the specific example shown in Fig. 1, the substrate 11 is made of a thin plate made of transparent SiO2. The metal structure 12 is made of gold, silver, copper or aluminum and is provided on the surface of the base 11 .

[0021] In the selective wavelength reflector 10, a plurality of unit patterns 13 each having one or more metal structures 12 are regularly arranged in the vertical and horizontal directions along the surface of the base 11 on the surface of the base 11. In the selective wavelength reflector 10, the unit patterns 13 are arranged so as to be in contact with adjacent unit patterns 13, and the metal structures 12 of a predetermined shape are arranged so as to appear periodically in the vertical and horizontal directions. In the selective wavelength reflector 10, the length and width of the metal structures 12 in the unit pattern 13 along the surface of the base 11 and the height from the surface of the base 11 are 10 nm or more and 650 nm or less.

[0022] In the selective wavelength reflector 10, the metallic structures 12 are not limited to those in a lattice shape as shown in Fig. 1, and the unit patterns 13 and the metallic structures 12 may have any shape. For example, the metallic structures 12 may have a square shape or a shape with square holes (the same as Fig. 1) as shown in Fig. 2(a), may have a circular shape or a shape with circular holes as shown in Fig. 2(b) and (f), may have a + shape or a shape with +-shaped holes as shown in Fig. 2(c), or may have a triangular shape or a shape with triangular holes as shown in Fig. 2(d) and (e). Note that Figs. 2(a) to (f) show the metallic structures 12 in a colored portion and the base 11 in a background, but the metallic structures 12 may have an inverted structure in which the colored portion shows the base 11 and the background shows the metallic structures 12.

[0023] In the selective wavelength reflector 10, metal structures 12 having the same shape but different orientations may be combined as shown in Figures 2(d) and (e), metal structures 12 having the same shape but different sizes may be combined as shown in Figures 2(b) and (f), or metal structures 12 having different shapes themselves may be combined. As shown in Figures 2(a) to (f), in the selective wavelength reflector 10, the unit patterns 13 are regularly arranged in the vertical and horizontal directions, respectively.

[0024] The selective wavelength reflector 10 can be manufactured, for example, by the method shown in FIG. 3 using semiconductor microfabrication technology or nanoimprint technology. That is, first, as shown in FIG. 3(b), a metal film 21 made of Au film, Ag film, Cu film, or Al film, which is the material of the metal structure 12, is formed by sputtering on the surface of a base 11 made of a transparent SiO2 substrate shown in FIG. 3(a). At this time, since the adhesive strength between Au and SiO2 and between Ag and SiO2 is weak, when forming the Au film or Ag film, the Au film or Ag film may be formed after forming a thin Cr film, Ti film, or ITO film on the surface of the base 11 for adhering Au or Ag to SiO2. After forming the metal film 21, a resist 22 is applied to the surface of the metal film 21 as shown in FIG. 3(c).

[0025] After applying the resist 22, as shown in FIG. 3(d), the resist 22 is partially exposed to an electron beam by electron beam (EB) patterning, and a desired pattern is formed with the remaining resist 22 through a development process. At this time, the pattern formed with the remaining resist 22 is a pattern of the planar shape of the metal structure 12 as shown in FIG. 2(a) to (f). Note that in FIG. 3(c) to (d), the desired pattern may be formed using a nanoimprint technique in which a polymer is applied and then patterned using a mold. After patterning, as shown in FIG. 3(e), the metal film 21 (including a Cr film, Ti film, or ITO film if present under the Au film or Ag film) is etched, and further, as shown in FIG. 3(f), the resist 22 is removed.

[0026] In this way, it is possible to manufacture the selective wavelength reflector 10 having the metal structures 12 provided on the surface of the base body 11. In this way, the selective wavelength reflector 10 can be manufactured using semiconductor microfabrication technology or nanoimprint technology, and even a large-area selective wavelength reflector can be manufactured at low cost.

[0027] The selective wavelength reflector 10 has excellent wavelength selectivity, being able to reflect or transmit any wavelength by adjusting the shape and size of the metal structures 12 in the unit pattern 13. In addition, by finely adjusting the shape and size of the metal structures 12, it is possible to increase the reflectance of light of a selected wavelength and increase the transmittance of wavelengths other than the selected wavelength. In addition, because such unit patterns 13 are regularly arranged, the selective wavelength can be optimized with higher precision than in the case of random arrangement.

[0028] In this way, the selective wavelength reflector 10 can be optimally designed to reflect and transmit light of a desired wavelength based on the concept of metamaterials. Since the metal structure 12 of the selective wavelength reflector 10 is made of gold, silver, copper, or aluminum, which are commonly used as metamaterial materials, the reflectance of the wavelength to be reflected can be effectively increased while the transmittance of that wavelength can be effectively decreased. Also, the transmittance of the wavelength to be transmitted can be effectively increased while the reflectance of that wavelength can be effectively decreased.

[0029] The selective wavelength reflector 10 can be used, for example, as windows for buildings and automobiles. In this case, when the metal structure 12 has a lattice shape (the inverted structure in Figs. 1 and 2(a)) or a shape having independent holes of a predetermined shape (the inverted structure in Figs. 2(b) to (f)), the metal structure 12 can be heated by passing electricity through it, and fog, frost, ice, etc. adhering to the window can be removed.

[0030] The selective wavelength reflector 10 may have a film made of ITO (indium tin oxide) on the front or back side of the base 11. In this case, the unit patterns 13 are configured to selectively reflect wavelengths in the near infrared region, thereby increasing the reflectance from the near infrared region to the infrared region.

[0031] Below, for a selective wavelength reflector 10 in which the metal structures 12 of the unit patterns 13 form a + shape (the structure of Figure 1 or Figure 2(c)) or a + shaped hole (the structure of Figure 2(a) or the inverted structure of Figure 2(c)), simulations were performed for a shape in which the metal structures 12 are independent for each unit pattern 13 without connecting adjacent unit patterns 13 (hereinafter referred to as a "cross structure"), and a shape in which adjacent unit patterns 13 are connected to form a lattice shape (hereinafter referred to as a "mesh structure").

[0032] In the simulation, the wavelength dependence of reflectance (zero-order reflection) and transmittance (zero-order transmission) was calculated by changing the size of the metal structure 12. In the simulation, the substrate 11 was made of a transparent thin plate made of SiO2, and the metal structure 12 was made of gold (Au), silver (Ag), or aluminum (Al).

[0033] [Cloth structure simulation] Here, the width of the vertical and horizontal lines of the +-shaped holes shown in Figs. 4(a) and (b) (in the case of the inverted structure of Fig. 2(c)) and the +-shaped holes shown in Figs. 4(c) and (d) (in the case of the structure of Fig. 2(c)) are w, the length of the vertical and horizontal lines are l, and the height from the substrate 11 is h. The shape of the unit pattern 13 along the surface of the substrate 11 is a square, and the length of one side is Λ. The angle of incidence of light with respect to the surface of the substrate 11 (angle with respect to the normal to the surface of the substrate 11) is θ. In the following simulations, the transmittance and reflectance are the average values ​​of p-polarized light and s-polarized light, that is, (transmittance or reflectance of p-polarized light + transmittance or reflectance of s-polarized light) / 2.

[0034] [Simulation Example 1] FIG. 5 shows the simulation results for the case where the metallic structure 12 is made of gold (Au) and has a +-shaped hole (the inverted structure in FIG. 2(c), see FIG. 4(a) and (b)), with w=30 nm, l=240 nm, h=20 nm, Λ=360 nm, and θ=0°. As shown in FIG. 5, it was confirmed that the reflectance of light of a specific wavelength in the near-infrared region of 780 nm to 1100 nm is high, the maximum reflectance is about 85%, and the transmittance is reduced to a few percent or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 50%, and the reflectance is reduced to about 20%.

[0035] In addition, the reflected energy of light with wavelengths between 780 nm and 1400 nm is 20.2 W / m 2 The reflected energy of light with wavelengths from 780 nm to 2500 nm is 25.6 W / m 2 It was.

[0036] [Simulation Example 2] The metallic structure 12 is made of gold (Au) and has a +-shaped hole (reversed structure in FIG. 2(c), see FIG. 4(a) and (b)). Simulation results for w=30 nm, l=200-300 nm, h=140 nm, Λ=360 nm, θ=0° and for w=40-100 nm, l=240 nm, h=140 nm, Λ=360 nm, θ=0° are shown in FIG. 6(a) and (b), respectively. As shown in FIG. 6(a) and (b), it was confirmed that the transmittance of light of a specific wavelength in the near-infrared region of 780 nm to 1100 nm was high at a maximum of 20% to 45%, and the transmittance of light in the visible light region of 350 nm to 780 nm was reduced to 5% or less.

[0037] In addition, as shown in Fig. 6(a), it was confirmed that as l increases, the wavelength of the transmitted light becomes longer, and the maximum transmittance and transmitted energy also increase.In addition, as shown in Fig. 6(b), it was confirmed that as w decreases, the wavelength of the transmitted light becomes longer.

[0038] [Simulation Example 3] Simulation results for the case where the metallic structure 12 is made of gold (Au) and has a + shape (see the structure in FIG. 2(c) and FIG. 4(c) and (d)), with w=30 nm, l=240 nm, h=60-140 nm, Λ=360 nm, and θ=0° are shown in FIG. 7(a) and (b). As shown in FIG. 7(a) and (b), it was confirmed that the reflectance of light of a specific wavelength in the near-infrared region of 780 nm to 1100 nm is high, the maximum reflectance is about 65-70%, and the transmittance is reduced to 10% or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 70-90%, and the reflectance is approximately 10% or less.

[0039] It was also confirmed that as the value of h increases, the wavelengths showing maximum reflectance and minimum transmittance shift toward the short wavelength side within the near infrared region of 780 nm to 1100 nm, and the value of the maximum reflectance increases slightly. In addition, the reflected energy of light with wavelengths of 780 nm to 1400 nm is 9.5 W / m when h = 60 nm. 2 , 12.2 W / m when h = 100 nm 2 , 13.3 W / m when h = 140 nm 2 In addition, the reflected energy of light with wavelengths from 780 nm to 2500 nm was 10.2 W / m when h = 60 nm. 2 , 12.9 W / m when h = 100 nm 2 , 13.4 W / m when h = 140 nm 2 It was.

[0040] [Simulation Example 4] Simulation results for the case where the metallic structure 12 is made of gold (Au) and has a + shape (see the structure in FIG. 2(c) and FIG. 4(c) and (d)), with w=30 nm, l=240 nm, h=60 nm, Λ=360 nm, and θ=0° to 60° are shown in FIG. 8(a) and (b). As shown in FIG. 8(a) and (b), it was confirmed that the reflectance of light of a specific wavelength in the near infrared region and in the vicinity of the wavelength of 780 nm to 1400 nm is high, the maximum reflectance is 60% or more, and the transmittance is reduced to 10% or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 75 to 90%, and the reflectance is approximately 15% or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is almost flat, and light in the visible light region is transmitted almost uniformly, as shown in FIG. 8(b).

[0041] [Simulation Example 5] Simulation results for the case where the metallic structure 12 is made of silver (Ag) and has a + shape (see the structure in FIG. 2(c) and FIG. 4(c) and (d)), with w=30 nm, l=240 nm, h=60 nm, Λ=360 nm, and θ=0° to 60° are shown in FIG. 9(a) and (b). As shown in FIG. 9(a) and (b), it was confirmed that the reflectance of light of a specific wavelength in the near infrared region and in the vicinity of the wavelength of 780 nm to 1200 nm is high, with the maximum reflectance being 65% or more, and the transmittance decreasing to about 5%. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, with the maximum transmittance being about 75 to 90%, and the reflectance being approximately 20% or less. It was also confirmed that the amount of reflected energy of light with a wavelength of 780 nm to 1400 nm was 11.2 W / m 2 The reflected energy of light with wavelengths from 780 nm to 2500 nm is 11.8 W / m 2 It was.

[0042] [Simulation Example 6] Simulation results for the case where the metallic structure 12 is made of aluminum (Al) and has a + shape (see the structure in FIG. 2(c) and FIG. 4(c) and (d)), w=30 nm, l=240 nm, h=60 nm, Λ=360 nm, and θ=0° to 60° are shown in FIG. 10(a) and (b). As shown in FIG. 10(a) and (b), it was confirmed that at θ=0° to 40°, the reflectance of light is highest near the boundary between the near-infrared region and the visible light region, with the maximum reflectance being about 35 to 40%. It was also confirmed that the reflectance of light in the near-infrared region of 780 nm to 1100 nm is generally high, and the transmittance is generally low. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, with the maximum transmittance being about 60 to 80%, and the reflectance decreasing to 15% or less. It was also confirmed that as the value of θ increases, the maximum reflectance decreases from approximately 40% to approximately 35%, and the minimum transmittance increases slightly.

[0043] 8 to 10, it was confirmed that under the same conditions, the reflectance in the near-infrared region is highest in silver, followed by gold and aluminum. In addition, it was confirmed that the transmittance in the visible light region is high overall for silver and gold, but decreases as the value of θ increases, and that for aluminum it is low in the wavelength region close to the near-infrared region.

[0044] [Simulation Example 7] Simulation results for the case where the metallic structure 12 is made of aluminum (Al) and has a + shape (see the structure in FIG. 2(c) and FIG. 4(c) and (d)), with w=80 nm, l=360 nm, h=60 nm, Λ=450 nm, and θ=0° to 60° are shown in FIG. 11(a) and (b). As shown in FIG. 11(a) and (b), it was confirmed that the reflectance of light in the near-infrared region and in the vicinity of the region, 780 nm to 1400 nm, was high, with the maximum reflectance being about 70% or more, and the transmittance decreasing to 10% or less. It was also confirmed that the transmittance of light in the visible light region, 350 nm to 780 nm, was high, with the maximum transmittance being about 50 to 70%, and the reflectance being approximately 20% or less. Furthermore, when compared with the results shown in Figure 10 for the same Al material, it was confirmed that as the sizes of w, l, and Λ increased, the maximum reflectance value increased, the minimum transmittance value decreased, and the wavelengths showing the maximum reflectance and minimum transmittance increased.

[0045] [Simulation Example 8] The metallic structure 12 is made of gold (Au) and has a + shape (structure in FIG. 2(c), see FIG. 4(c) and (d)), and the parameters are k and p, w=k (nm), l=p×k (nm), h=60 nm, Λ=1.5×l (nm), and θ=0°. In this case, the simulation results for k=10-30, p=8 (w=k=10-30 nm, l=8k=80-240 nm, h=60 nm, Λ=12k=120-360 nm, θ=0°) are shown in FIG. 12(a) and (b). 13(a) and (b) show the simulation results for k=30 and p=1-12 (w=k=30 nm, l=30, p=30-360 nm, h=60 nm, Λ=45, p=45-540 nm, θ=0°). Note that FIG. 8 shows the simulation results for k=30 and p=8.

[0046] 12(a) and (b), it was confirmed that as the value of k increases, the specific wavelengths showing the maximum reflectance and minimum transmittance shift to the longer wavelength side in the near infrared region of 780 nm to 1100 nm, the maximum reflectance value increases from about 40% to about 65%, and the minimum transmittance value decreases from about 20% to about 5%. From this result, it can be said that the range of wavelengths to be reflected and the reflectance can be arbitrarily set by adjusting the value of k.

[0047] 13(a) and (b), it was confirmed that as the value of p increases, the specific wavelengths showing the maximum reflectance and the minimum transmittance move to the long wavelength side within the range of 600 nm to 1500 nm from the visible light region to the near infrared region and its vicinity, the maximum reflectance value changes between about 25% to about 65%, and the minimum transmittance value changes between about 30% to about 5%. In particular, it was confirmed that when p=4 to 12, the maximum reflectance is high at about 50% or more, and the minimum transmittance is low at about 10% or less. From this result, it can be said that the range of wavelengths to be reflected and the reflectance can be arbitrarily set by adjusting not only the value of k but also the value of p.

[0048] [Simulation Example 9] As shown in FIG. 14(a), the metallic structure 12 is made of gold (Au) and has a + shape (see the structure in FIG. 2(c), and FIG. 4(c) and (d)). Two selective wavelength reflectors 10 with w=30 nm, l=240 nm, h=60 nm, and Λ=360 nm are stacked. The simulation results for θ=0° are shown in FIG. 14(b) and (c). The gap between the metallic structure 12 sandwiched between the substrates 11 is filled with SiO2, which is the same material as the substrate 11. The thickness d of the substrate 11 is set to d=20 nm. For comparison, the simulation results for a single layer of selective wavelength reflector 10 of the same size (θ=0° in FIG. 8(a) and (b)) are also shown in the figure. As shown in Figures 14(b) and (c), it was confirmed that the reflectance of light of a specific wavelength in the near-infrared region of 780 nm to 1100 nm is greater when the selective wavelength reflector 10 is two layers than when it is one layer.

[0049] In addition, the reflected energy of light with wavelengths between 780 nm and 1400 nm is 9.5 W / m2 for one layer. 2 and 12.2 W / m for two layers. 2 In addition, the reflected energy of light with wavelengths from 780 nm to 2500 nm was 10.2 W / m2 for one layer. 2 and 13.2 W / m for two layers. 2 From these results, it can be said that the reflectance can be increased by stacking a plurality of selective wavelength reflectors 10 and increasing the number of layers.

[0050] [Simulation Example 10] As shown in FIG. 15(a), the metallic structures 12 are made of gold (Au) and are in the shape of a + (see the structure in FIG. 2(c), and FIGS. 4(c) and (d)). A simulation was performed on four metallic structures 12 formed in two rows and two columns in a unit pattern 13. Of the four metallic structures 12, two diagonally positioned metallic structures 12 were grouped together, and the metallic structures 12 in each group were the same size. That is, the first metallic structure 12 was set to w1=20 nm, l1=160 nm, and h=60 nm, and the second metallic structure 12 was set to w2=25 nm, l2=200 nm, and h=60 nm. In addition, Λ=270 nm, and θ=0° to 60°. The simulation results are shown in FIG. 15(b) and (c).

[0051] As shown in Fig. 15(b) and (c), there are multiple peaks showing the maximum reflectance and the minimum transmittance, and it was confirmed that the width of the wavelength region where the reflectance is high and the transmittance is low is wider than when the size of the metal structure 12 is one type (for example, see Fig. 8). It was also confirmed that the reflectance of light in the near infrared region of 780 nm to 1100 nm is high, the maximum reflectance is about 50%, and the transmittance is reduced from about 20% to less than that. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 70 to 85%, and the reflectance is approximately 20% or less. It was also confirmed that in the visible light region, the transmittance is reduced as the value of θ increases, and the transmitted light becomes closer to red.

[0052] [Simulation Example 11] 16(a) and (b) show the simulation results when the first set of metal structures 12 is set to w1=40 nm, l1=200 nm, and h=80 nm, the second set of metal structures 12 is set to w2=50 nm, l2=260 nm, and h=80 nm, and Λ=300 to 380 nm and θ=0° in a 2-row, 2-column pattern similar to that shown in FIG. 15(a). As shown in FIG. 16(a) and (b), it was confirmed that there were multiple peaks indicating the maximum reflectance and the minimum transmittance, similar to FIG. 15. It was also confirmed that the reflectance of light in the near-infrared region and in the vicinity of 780 nm to 1200 nm was high, the maximum reflectance was about 50 to 65%, and the transmittance was reduced to about 10%. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm was high, the maximum transmittance was about 80%, and the reflectance was reduced to 10% or less.

[0053] Furthermore, compared with the results of the same Au material shown in Figure 15, it was confirmed that as the sizes of w, l, and Λ increase, the width of the wavelength region with high reflectance and low transmittance becomes wider and the maximum reflectance increases. It was also confirmed that the number of peaks showing the maximum reflectance and minimum transmittance changes depending on the size of Λ.

[0054] [Simulation Example 12] In a 2-row, 2-column pattern similar to that shown in FIG. 15(a), the first set of metal structures 12 are set to w1=40 nm, l1=200 nm, and h=60 nm, the second set of metal structures 12 are set to w2=50 nm, l2=260 nm, and h=60 nm, and Λ=300 nm and θ=0° to 60°. Simulation results are shown in FIG. 17(a) and (b) when the first set of metal structures 12 are set to w2=50 nm, l2=260 nm, and h=60 nm, and Λ=300 nm and θ=0° to 60°. As shown in FIG. 17(a) and (b), it was confirmed that there were multiple peaks indicating the maximum reflectance and the minimum transmittance, similar to FIG. 15. It was also confirmed that the reflectance of light in the near-infrared region and in the vicinity of 780 nm to 1200 nm was high, the maximum reflectance was about 50 to 65%, and the transmittance was reduced to about 10%. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm was high, the maximum transmittance was about 70%, and the reflectance was reduced to 20% or less.

[0055] In addition, compared with the results shown in Figure 15 for the same Au material, it was confirmed that as the sizes of w, l, and Λ increased, the width of the wavelength region with high reflectance and low transmittance became wider and the maximum reflectance became larger. In addition, the reflected energy of light with wavelengths from 780 nm to 1400 nm was 11.5 W / m 2 The reflected energy of light with wavelengths from 780 nm to 2500 nm is 12.9 W / m 2 It was also confirmed that in the visible light region, as the value of θ increases, the transmittance decreases and the transmitted light becomes closer to red.

[0056] [Simulation Example 13] 18(a) and (b) show the simulation results when the first set of metal structures 12 is set to w1=70 nm, l1=240 nm, and h=60 nm, the second set of metal structures 12 is set to w2=90 nm, l2=280 nm, and h=60 nm, and Λ=350 nm and θ=0° to 60° in a 2-row, 2-column pattern similar to that shown in FIG. 15(a). As shown in FIG. 18(a) and (b), it was confirmed that there were multiple peaks indicating the maximum reflectance and the minimum transmittance, similar to FIG. 15. It was also confirmed that the reflectance of light in the near-infrared region and in the vicinity of 780 nm to 1200 nm was high, the maximum reflectance was about 60 to 70%, and the transmittance was reduced to about 5%. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm was high, the maximum transmittance was about 50 to 70%, and the reflectance was reduced to 20% or less.

[0057] In addition, compared to the results in Figure 15 for the same Au material, it was confirmed that as the sizes of w, l, and Λ increased, the width of the wavelength region with high reflectance and low transmittance became wider, but compared to the results in Figure 17, it was confirmed that the width of the wavelength region with high reflectance and low transmittance hardly changed even when the sizes of w, l, and Λ increased. In addition, compared to the results in Figures 15 and 17, it was confirmed that as the sizes of w, l, and Λ increased, the maximum reflectance increased.

[0058] [Simulation Example 14] FIG. 19 shows a simulation result in a 2-row, 2-column pattern similar to that shown in FIG. 15(a), in which the metal structures 12 are made of silver (Ag), the first set of metal structures 12 are w1=40 nm, l1=200 nm, and h=60 nm, the second set of metal structures 12 are w2=50 nm, l2=260 nm, and h=60 nm, and Λ=300 nm and θ=0° are set. As shown in FIG. 19, it was confirmed that the Ag case had multiple peaks indicating maximum reflectance and minimum transmittance, as in the Au case. It was also confirmed that the reflectance of light in the near-infrared region and in the vicinity of the 780 nm to 1200 nm was high, the maximum reflectance was about 70%, and the transmittance was reduced to 10% or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm was high, the maximum transmittance was about 80%, and the reflectance was reduced to 10% or less.

[0059] In addition, when compared with Figure 17, which shows the results for the Au product under the same conditions, it was confirmed that the wavelength range in which the reflectance is high and the transmittance is low is almost the same, but the maximum reflectance value is larger. Also, the reflected energy of light with wavelengths from 780 nm to 1400 nm was 12.1 W / m 2 The reflected energy of light with wavelengths from 780 nm to 2500 nm is 13.4 W / m 2 It was.

[0060] [Simulation Example 15] 15(a), the metal structures 12 are made of gold (Au), the first set of metal structures 12 are set to w1=40 nm, l1=200 nm, h=60 nm, the second set of metal structures 12 are set to w2=50 nm, l2=260 nm, h=60 nm, Λ=300 nm, θ=0°, and an adhesive film is formed between each metal structure 12 and the base 11 to a thickness of 1 nm to 10 nm. The simulation results are shown in Fig. 20 and Fig. 21. The case where the adhesive film is a Ti film is shown in Fig. 20(a) and (b), and the case where the adhesive film is a Cr film is shown in Fig. 21(a) and (b).

[0061] As shown in Fig. 20 and Fig. 21, compared with Fig. 17 showing the results under the same conditions except for the presence of the Ti film or Cr film, it was confirmed that the wavelength ranges where the reflectance is high and the transmittance is low are almost the same, and when the thickness of the Ti film or Cr film is 1 nm and 2 nm, both the reflectance and the transmittance are almost the same as those without the Ti film or Cr film. It was also confirmed that as the Ti film or Cr film becomes thicker, the reflectance decrease amount and the transmittance increase amount in the near infrared region and in the vicinity of 780 nm to 1200 nm increase, and the reflectance increase amount and the transmittance decrease amount in the visible light region of 350 nm to 780 nm and higher wavelength side than 1200 nm increase. It was also confirmed that the Cr film has a slightly larger change in reflectance and transmittance than the Ti film in Fig. 20 compared with the Cr film in Fig. 21. It is to be noted that these results are also confirmed when the light incidence angle θ is greater than 0° and less than 60°, although not shown in the figure. From these results, it can be said that it is preferable for the adhesive film to be thin, ie, 2 to 3 nm or less, and that a Ti film is more preferable than a Cr film.

[0062] [Simulation Example 16] As shown in FIG. 22(a), the metallic structures 12 are made of gold (Au) and are in the shape of a + (see the structure in FIG. 2(c), and FIGS. 4(c) and (d)). A simulation was performed on nine metallic structures 12 formed in three rows and three columns in a unit pattern 13. The metallic structures 12 were of three different sizes, and one of each type was arranged in each row and each column. The first type of metallic structure 12 had w1=20 nm, l1=160 nm, and h=60 nm, the second type of metallic structure 12 had w2=25 nm, l2=200 nm, and h=60 nm, and the third type of metallic structure 12 had w3=30 nm, l3=240 nm, and h=60 nm. In addition, Λ=300 nm, and θ=0° to 60°. The simulation results are shown in FIG. 22(b) and (c).

[0063] As shown in Figs. 22(b) and (c), there are multiple peaks indicating the maximum reflectance and the minimum transmittance, and it was confirmed that the width of the wavelength region where the reflectance is high and the transmittance is low is wider than when the size of the metal structure 12 is one type (see Fig. 8, for example) and when the size of the metal structure 12 is two types (see Fig. 15, for example). It was also confirmed that the reflectance of light in the near infrared region and in the vicinity of the wavelength of 780 nm to 1300 nm is high, the maximum reflectance is about 45%, and the transmittance is reduced to about 20% or less. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 75 to 85%, and the reflectance is about 15% or less. It was also confirmed that in the visible light region, the transmittance is reduced as the value of θ increases, and the transmitted light becomes closer to red.

[0064] Figures 23(a) and (b) show the results of reflectance and transmittance when θ=0° for the cases where there is one size type of metal structure 12, two sizes (Figure 15), and three sizes (Figure 22). When there is one size type, the settings were w=20 nm, l=160 nm, h=60 nm, and Λ=240 nm. As shown in Figures 23(a) and (b), it is clear that the width of the wavelength region where reflectance is high and transmittance is low becomes wider as the number of sizes of metal structure 12 increases. In addition, the reflected energy amount of light with wavelengths from 780 nm to 1400 nm was 8.6 W / m when there was one size type. 2 and 9.3W / m when there are two sizes. 2 and 8.4W / m for three sizes. 2 In addition, the reflected energy of light with wavelengths between 780 nm and 2500 nm was 9.0 W / m2 when there was only one size. 2 and 9.9W / m when there are two sizes. 2 and 9.0W / m when there are three sizes. 2 It was.

[0065] [Mesh structure simulation] Here, as shown in Fig. 1, the inside of the lattice is a square, the width of the lattice line is a, the length of one side of one lattice (the distance between the centers of adjacent parallel lines) is g, and the height of the lattice from the base 11 is t. Also, it is assumed that light is always incident from a direction perpendicular to the surface of the base 11. In this case, the shape of the unit pattern 13 along the surface of the base 11 is a square, and if the length of one side is Λ, then Λ = g.

[0066] [Simulation Example 17] Simulation results for the case where the metallic structure 12 is made of gold (Au) and has a lattice shape (the structure in FIG. 1 and the inverted structure in FIG. 2(a)), a=100 nm, g=450 nm, and t=100-200 nm are shown in FIG. 24. As shown in FIG. 24, it was confirmed that the reflectance of light in the near-infrared region of 780 nm to 2500 nm is generally high, the maximum reflectance is about 45-75%, and the transmittance is reduced to about 20-50%. It was also confirmed that the transmittance of light in the visible light region of 350 nm to 780 nm is high, the maximum transmittance is about 70-85%, and the reflectance is reduced to 10% or less.

[0067] It was also confirmed that as the value of t increases, the reflectance increases overall and the transmittance decreases overall in the near infrared region. In addition, the reflected energy of light with wavelengths of 780 nm to 1400 nm was 10.3 W / m when t = 100 nm. 2 and 15.0 W / m when t=150 nm. 2 and 17.7 W / m when t = 200 nm. 2 In addition, the reflected energy of light with wavelengths from 780 nm to 2500 nm was 14.5 W / m when t = 100 nm. 2 and 21.1 W / m when t=150 nm. 2 and 25.0 W / m when t = 200 nm. 2 It was.

[0068] [Simulation Example 18] Simulation results are shown in FIG. 25 for the case where the metallic structure 12 is made of gold (Au) and has a lattice shape (the structure in FIG. 1 and the inverted structure in FIG. 2(a)), a=140-160 nm, g=a×4 (560-640 nm), and t=200 nm. As shown in FIG. 25, it was confirmed that the light transmittance is high in the near-infrared region of 780 nm to 1100 nm, the maximum transmittance is about 70-80%, and the reflectance is reduced to about 10%. In addition, it was confirmed that the light transmittance and reflectance are low in the visible light region of 350 nm to 780 nm, being approximately 20% or less.

[0069] It was also confirmed that the reflectance of light at 1100 nm to 2500 nm on the long wavelength side of the near infrared region is generally high, and as the wavelength becomes longer, the reflectance increases, the maximum reflectance becomes about 90% or more, while the transmittance decreases, and the maximum transmittance becomes about 5% or less. It was also confirmed that as the values ​​of a and g increase, both the reflectance curve and the transmittance curve shift overall to the long wavelength side.

[0070] [Simulation Example 19] Simulation results are shown in Fig. 26 for the case where the metallic structure 12 is made of gold (Au), silver (Ag) or aluminum (Al) and has a lattice shape (the structure in Fig. 1 and the inverted structure in Fig. 2(a)), with a = 100 nm, g = 400 nm, and t = 200 nm. As shown in Fig. 26, it was confirmed that gold, silver, and aluminum all have high reflectances of light in the near infrared region of 780 nm to 1000 nm, with the reflectance generally being approximately 60% or more and the transmittance being approximately 30% or less. It was confirmed that the reflectances of aluminum and silver in this region are slightly higher than that of gold.

[0071] It was also confirmed that the transmittance of light in the visible light region of 400 nm to 780 nm is high, with a maximum transmittance of approximately 80 to 90%, and the reflectance decreasing to a few percent or less. It was confirmed that the transmittance in this region is highest for silver, followed by gold and aluminum. Furthermore, when the metal structure 12 is made of gold (Au), the reflected energy amount of light in the wavelength range of 780 nm to 1400 nm is 22.5 W / m2 The reflected energy of light with wavelengths from 780 nm to 2500 nm is 30.5 W / m 2 It was.

[0072] Of the above simulation results, the selective wavelength reflectors 10 of simulation Example 1 (see FIG. 5), Examples 3 to 17 (see FIGS. 7 to 12, 14 to 24), and Example 19 (see FIG. 26) selectively reflect wavelengths of 780 nm to 1100 nm in the near-infrared region, while at the same time having high transmittance for visible light with wavelengths of 350 nm to 780 nm. For this reason, these selective wavelength reflectors 10 can be used as near-infrared reflection filters, and when used as windows for buildings or automobiles, they can prevent a rise in temperature indoors or inside a vehicle due to sunlight in the summer, and can reduce power consumption in air conditioners, etc., thereby contributing to power saving and energy conservation.

[0073] Moreover, the selective wavelength reflector 10 of the simulation example 2 (see FIG. 6) selectively reflects wavelengths of 350 nm to 780 nm in the visible light region, and at the same time has high transmittance for near-infrared rays with wavelengths of 780 nm to 1100 nm. Therefore, these selective wavelength reflectors 10 can be used as near-infrared transmission filters, and when used in windows of buildings or factories, they can reflect visible light from indoor lighting into the room and efficiently expel heat trapped inside the room to the outside.

[0074] Moreover, the selective wavelength reflector 10 of simulation Example 18 (see FIG. 25) selectively reflects wavelengths of 1100 nm to 2500 nm on the long wavelength side of the near infrared region, and at the same time has high transmittance for light of 780 nm to 1100 nm on the short wavelength side of the near infrared region. In this way, the selective wavelength reflector 10 can reflect or transmit any wavelength by adjusting the shape and size of the metal structure 12.

[0075] Moreover, the selective wavelength reflectors 10 of simulation examples 4 (see FIG. 8), 5 (see FIG. 9), 7 (see FIG. 11), 10 (see FIG. 15), 12 (see FIG. 17), 13 (see FIG. 18), and 16 (see FIG. 22) have a lower transmittance in the visible light region as the value of θ increases. For this reason, it is considered that these selective wavelength reflectors 10 are effective when used as anti-snooping filters for displays of mobile phones, personal computers, televisions, etc. EXAMPLES

[0076] The selective wavelength reflector 10 was manufactured by the method shown in FIG. 3, and the reflectance and transmittance were measured. As shown in FIG. 27, the manufactured selective wavelength reflector 10 has a substrate 11 made of transparent SiO2, and a metal structure 12 made of aluminum (Al) and formed in a + shape (see the structure in FIG. 2(c), and FIGS. 4(c) and (d)). The selective wavelength reflector 10 has a plurality of unit patterns 13, each having a metal structure 12, regularly arranged in four regions of 1.5 mm×1.5 mm on the surface of the substrate 11. The selective wavelength reflector 10 has four different patterns in which the sizes of the metal structures 12 are (w, l)=(60 nm, 340 nm), (70 nm, 350 nm), (80 nm, 360 nm), and (90 nm, 370 nm) in order from the left region in FIG. 27. In all four patterns, h=60 nm and Λ=450 nm.

[0077] The reflectance and transmittance were measured in the wavelength range of 400 to 1700 nm for all four patterns of the selective wavelength reflector 10 shown in FIG. 27. An objective lens and a spectrometer were used for the measurements. In the wavelength range of 400 to 860 nm, the reflectance was measured with an integration time of 6 msec, and 50 measurements were averaged. In the transmittance was measured with an integration time of 20 msec, and 20 measurements were averaged. In the wavelength range of 860 to 1700 nm, the reflectance was measured with an integration time of 650 msec, and two measurements were averaged. In the transmittance was measured with an integration time of 850 msec, and two measurements were averaged. In addition, the incident angle θ of light was set to 0° in both cases.

[0078] For measurements in the wavelength range of 400 to 860 nm, an objective lens "MSPlan20 (NA0.4)" manufactured by Olympus Corporation was used, and a spectrometer "HR4000CG-UV-NIR" manufactured by Ocean Optics, Inc. was used. For measurements in the wavelength range of 860 to 1700 nm, an objective lens "MIRPlan20 (NA0.4)" manufactured by Olympus Corporation was used, and a spectrometer "NIR512" manufactured by Ocean Optics, Inc. was used.

[0079] The measurement results of the reflectance and transmittance of the selective wavelength reflector 10 having the patterns of (w, l)=(80 nm, 360 nm) and (60 nm, 340 nm) are shown in Figs. 28(a) and (b), respectively. The calculation results of the simulation of the reflectance and transmittance for each pattern are also shown by dashed lines in Figs. 28(a) and (b). The simulation results of the reflectance and transmittance in Fig. 28(a) are the same as the simulation results for θ=0° in Fig. 11(a) and θ=0° in Fig. 11(b). The measurement results of the reflectance and transmittance for the four patterns shown in Fig. 27 are summarized in Fig. 29.

[0080] As shown in Figs. 28(a) and (b), it was confirmed that the measured values ​​of reflectance and transmittance were in good agreement with the calculated values ​​in the simulation for both patterns. From this, it is considered that a pattern of a metal structure 12 having a desired transmittance and reflectance can be designed based on the simulation results. In addition, as shown in Fig. 29, it was confirmed that in these four patterns, the reflectance of light in the near infrared region and its vicinity from 780 nm to 1200 to 1500 nm is high, the maximum reflectance is about 60 to 80%, and the transmittance decreases from about 10% to less. It was also confirmed that the larger the sizes of w and l, the higher the maximum reflectance. It was also confirmed that the transmittance of light in the visible light region of 680 nm or less is particularly high, about 60 to 80%, and the reflectance is about 20% or less. It was also confirmed that the smaller the sizes of w and l, the higher the transmittance, and that high transmittance is maintained up to a smaller wavelength region. [Explanation of symbols]

[0081] 10. Selective Wavelength Reflector 11 Base 12 Metal Structure 13 Unit Pattern 21 Metal Film 22 Resist

Claims

1. The present invention comprises a light-transmitting substrate having a surface on which a plurality of unit patterns each having one or more metal structures are regularly arranged in a vertical direction and a horizontal direction along the surface of the substrate, In the unit pattern, the shape of the metal structure when viewed from a direction perpendicular to the surface of the base has a + shape, and when the width of the vertical and horizontal lines of the + shape is w (nm), the length of the vertical and horizontal lines is l (nm), and the length of one side of the unit pattern is Λ (nm), 240≦l≦370, 30≦w≦90, and 360≦Λ≦450; The maximum reflectance of light having a wavelength of 780 nm or more and less than 900 nm is 40% or more, and the maximum transmittance of light having a wavelength of 350 nm to 780 nm is 50% or more. A selective wavelength reflector.

2. 2. The selective wavelength reflector according to claim 1, wherein the unit patterns are arranged so as to be in contact with adjacent unit patterns.

3. 3. The selective wavelength reflector according to claim 1, wherein the maximum reflectance of light having a wavelength of 780 nm or more and less than 900 nm is 60% or more, and the maximum transmittance of light having a wavelength of 350 nm to 780 nm is 70% or more.

4. 4. A selective wavelength reflector as described in any one of claims 1 to 3, characterized in that the length and width along the surface of the base, and the height from the surface of the base, of the metal structures in the unit pattern are 10 nm or more and 650 nm or less.

5. 5. The selective wavelength reflector according to claim 1, wherein the metallic structure is made of gold, silver, copper or aluminum.

6. The substrate has a plate shape, The reflecting layer is formed by laminating a plurality of the reflecting layers each including the base and the unit pattern.

6. A selective wavelength reflector according to claim 1 .

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