JP2010243981A - Transparent heat ray reflection sheet and heat ray shielding window glass using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent heat ray reflection sheet which has high transparency in a visible light region, has high reflectivity in an infrared region, and has a large area, at a low cost. <P>SOLUTION: A transparent heat ray reflection film is the transparent heat ray reflection sheet including a base material and a metal grating or metal dots comprising a reflective material disposed at equal intervals in a two-dimensional grating shape on the base material. For the transparent heat ray reflection sheet, visible light transmittance is 50% or higher and the maximum value of reflectance in the wavelength region of the wavelength 900 nm to 1,500 nm is 50% or higher. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a transparent heat ray reflective sheet having high transparency in the visible light region and having high reflectivity in the infrared light region from near infrared rays to infrared rays, and a heat ray shielding window glass using this sheet. .

  In recent years, there has been an increasing demand for a heat ray-shielding glass that shields the heat ray region of solar rays flowing into the interiors of houses and buildings and automobiles, thereby reducing the heat sensation and the load on the air conditioner. In particular, in an automobile or a building having a large wall surface occupancy ratio of the window glass, the amount of incident sunlight is large, and the room temperature rise in summer is remarkable. In order to suppress the increase in room temperature and to achieve an appropriate temperature, the output of the air conditioner must be considerably increased, so that not only is the load imposed on the air conditioner, but the energy consumption is also considerable. In the case of an automobile, the compressor of an air conditioner is also driven by the engine, so that gasoline consumption and exhaust gas emission are increased. Furthermore, in a cold region, heat from heating is dissipated outside the room through the window glass in the winter season, and extra heating energy is required, which is not preferable from the viewpoint of energy saving.

  In order to solve the above-mentioned problems, attempts have been made to provide a heat ray reflective film on the surface of the window glass to suppress the temperature rise in the room or the interior of the vehicle, and to prevent the heating heat in the winter in cold regions.

  The light emitted from the sun has a wide spectrum from the ultraviolet region to the infrared light region. Visible light has a wavelength range from 380 nm to 780 nm ranging from purple to yellow to red light, and occupies about 45% of sunlight. As for infrared light, those close to visible light are called near-infrared rays (wavelengths of 780 nm to 2500 nm), and more than that are called mid-infrared rays and occupy about 50% of sunlight. The light energy in this region is as small as about one-tenth or less compared with ultraviolet light, but its thermal effect is large, and when absorbed by a substance, it is released as heat and causes a rise in temperature. For this reason, it is also called a heat ray, and by blocking these rays, the temperature rise in the room can be suppressed. In addition, it is possible to suppress the heat of the winter in the cold region from being dissipated outside the room.

  Examples of the substance having the ability to reflect heat rays with a single material include conductive substances such as metal and tin-doped indium oxide (ITO). These substances have a specific characteristic that they have a free electron density of a certain level or more, and reflect light on the longer wavelength side than a certain wavelength and transmit light on the shorter wavelength side by plasma reflection by this free electron. Yes. It is known that the wavelength serving as the boundary exists in the visible light region for metals and in the near-infrared light region for semiconductors.

Japanese Patent Laid-Open No. 2001-179887 JP 2005-343732 A JP 2007-152773 A Japanese Patent Laid-Open No. 7-70363 JP 2004-217432 A JP-A-8-239244 JP 11-317593 A JP 2002-328234 A

  The most common heat ray reflective film is mainly focused on direct sunlight shielding, and is formed by forming a metal thin film on glass by vapor deposition or sputtering (Patent Document 1). However, in order to shield more heat, the metal film must be thickened, and as a result, there is a drawback that transparency is lowered. In addition, there is a problem that electromagnetic waves are reflected by the metal film, making it difficult for the mobile phone to communicate.

  On the other hand, when importance is attached to transparency, sputtering of a transparent conductive oxide material such as tin-doped indium oxide (ITO), tin oxide, or zinc oxide is performed by sputtering with a plasma reflection rising in the near infrared region. And a method of forming by spray pyrolysis (Patent Document 2, Patent Document 3). As another method, there is a method in which the particle diameter of an oxide is set to 0.1 μm or less so as to reduce light scattering, and a coating is formed by uniformly dispersing the oxide (Patent Document 4). According to this method, a highly transparent heat ray reflective film can be obtained by an inexpensive manufacturing method. However, in these cases, although the transparency in the visible light region is high, the reflection in the infrared light region is not sufficient.

  In order to increase the reflectance in the infrared light region while maintaining the transparency in the visible light region as much as possible, as another aspect, a laminated film in which metal thin films such as Ag and oxide thin films are alternately laminated (patents) Document 5) discloses a laminated film formed by laminating a plurality of oxide thin films having different refractive indexes (Patent Document 6). However, when the heat ray reflective film is formed in a large area by this method, there is a problem that the manufacturing cost becomes high. In addition, it is difficult to freely change the design of transmission and reflection characteristics according to the application and customer's request, and there are many restrictions on the constituent materials.

  Also, an electromagnetic wave shield that transmits visible light and shields electromagnetic waves by providing a grid-like metal structure on a substrate is generally known (Patent Document 7). This is because the gap between the metal grids is as wide as several to several tens of micrometers, so the transmittance in the visible light region is high, but the transmittance in the infrared light region is also high, so it cannot be used for heat ray reflection. .

  A wire grid polarizer is known as a product having a narrow metal lattice spacing (Patent Document 8). This is because the interval between the metal gratings is as narrow as several tens to several hundreds of nanometers and is a one-dimensional grating. Sex is not ensured. In addition, even when two wire grid polarizers are stacked such that the metal grids are orthogonal to each other like an electromagnetic wave shield, the transmittance in the visible light region is lowered and transparency is not ensured.

  The present invention has been made in view of such a point, and has a transparent heat ray reflective sheet that has high transmittance in the visible light region and high reflectivity in the infrared light region, and has a large area at low cost. The purpose is to provide.

  The transparent heat ray reflective sheet of the present invention comprises a base material, and a metal grid composed of a reflective material arranged at equal intervals in a two-dimensional lattice pattern on the base material, and the transparent heat ray reflective sheet comprises: The visible light transmittance is 50% or more, and the maximum reflectance is 50% or more in a wavelength region from 900 nm to 1500 nm.

  In the transparent heat ray reflective sheet of the present invention, the pitch interval of the metal grid is 800 nm or less, the maximum height in the cross-sectional view of the metal grid is 20 nm or more, and the width W1 and the pitch in the cross-sectional view. It is preferable that the relationship W1 / P1 between the distance P1 is 0.05 or more and 0.40 or less.

  The transparent heat ray reflective sheet of the present invention comprises a base material and metal dots made of a reflective material arranged at regular intervals on the base material, and the transparent heat ray reflective sheet has a visible light transmittance. Is 50% or more, and the maximum reflectance exceeds 50% in the wavelength region of 900 nm to 1500 nm.

  In the transparent heat ray reflective sheet of the present invention, the pitch interval of the metal dots is 2000 nm or less, the maximum height in the cross-sectional view of the metal dots is 20 nm or more, and the width W2 and the pitch in the cross-sectional view. It is preferable that the relationship W2 / P2 between the distance P2 is 0.30 or more and 0.70 or less.

  In the transparent heat ray reflective sheet of the present invention, the reflective material is preferably composed of a material selected from the group consisting of aluminum, an aluminum alloy, silver, and a silver alloy.

  The heat ray blocking window glass of the present invention comprises a plate glass and the transparent heat ray reflective sheet attached on the plate glass.

  The light beam separation method of the present invention is characterized in that visible light and infrared light are separated by irradiating the transparent heat ray reflective sheet with light beams in the entire wavelength region.

  The transparent heat ray reflective sheet of the present invention comprises a base material, and a metal grid composed of a reflective material arranged at equal intervals in a two-dimensional lattice pattern on the base material, and the transparent heat ray reflective sheet comprises: The visible light transmittance is 50% or more, and the maximum reflectance is 50% or more in the wavelength region from 900 nm to 1500 nm. Therefore, the visible light region has high transmittance and the infrared light region. Is a large-area transparent heat ray reflective sheet that has high reflectivity and can be produced at low cost. In addition, this transparent heat ray reflective sheet has a small attenuation of electromagnetic waves due to reflection and absorption, and can use electronic devices such as mobile phones without hindrance, and the metal grid or metal dot is an inorganic substance, so that it is resistant to heat and light. Excellent durability.

It is a schematic sectional drawing of the transparent heat ray reflective sheet which concerns on embodiment of this invention. It is a schematic sectional drawing of the transparent heat ray reflective sheet which concerns on embodiment of this invention. It is a schematic sectional drawing of the heat ray blocking window glass which concerns on implementation of this invention. 1 is a schematic cross-sectional perspective view of a multilayer heat ray blocking window glass according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The transparent heat ray reflective sheet which concerns on embodiment of this invention arrange | positions regularly the metal grid or metal dot comprised with the reflective material on a base material, It is characterized by the above-mentioned.

  Fig.1 (a) is a schematic sectional drawing which shows an example of the transparent heat ray reflective sheet | seat which concerns on embodiment of this invention. The transparent heat ray reflective sheet shown in FIG. 1A is mainly composed of a base material 1 and a two-dimensional metal lattice 2 arranged on the base material 1. The metal grid 2 is provided at a predetermined interval (pitch).

  The material constituting the substrate 1 is not particularly limited as long as it is a resin that is substantially transparent in the visible light region. For example, polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin resin (COP) ), Amorphous thermoplastic resins such as cross-linked polyethylene resin, polyvinyl chloride resin, polyarylate resin, polyphenylene ether resin, modified polyphenylene ether resin, polyetherimide resin, polyether sulfone resin, polysulfone resin, polyether ketone resin Crystalline thermoplastics such as polyethylene terephthalate (PET) resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal resin, polyamide resin And resins, acrylic, epoxy, include ultraviolet (UV) curable resin or thermosetting resin such as urethane. A substrate made of PET resin or polycarbonate resin is preferable because it is inexpensive and has good weather resistance. Moreover, transparent inorganic solid base materials, such as glass and sapphire, may be sufficient.

  The metal grating 2 is preferably made of a material (reflective material) exhibiting reflectivity with respect to the infrared light region. As the reflective material, Al, In, Sn, Sb, Bi, Cu, Ag, Au, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Pd, Pt Metals such as these, alloys thereof, tin-doped indium oxide (ITO), zinc oxide, tin oxide, niobium-added titanium oxide, ruthenium oxide, iridium oxide, and other conductive oxides can be used. In particular, Al, Al alloy, Ag, and Ag alloy are preferable because of high reflectivity in the infrared light region.

  By setting the dimension and pitch interval of the metal grid 2 in a cross-sectional view within a predetermined interval range, the infrared light region can be reflected and the visible light region can be transmitted. Preferably, the pitch interval is 800 nm or less, the maximum value of the height of the metal grid in the cross-sectional view is 20 nm or more, and the relationship W1 / P1 between the width W1 and the pitch interval P1 in the cross-sectional view is 0. It is preferable that it is 05 or more and 0.40 or less. The width W1 and the pitch interval P1 in the cross-sectional view are dimensions in a cross-sectional view of the metal grid 2 as shown in FIG.

  When the pitch interval of the metal grating 2 is wider than 800 nm, the transmittance in the visible light region is lowered and the visibility is extremely deteriorated. The minimum pitch interval is preferably 100 nm or more from the viewpoint of workability. Further, when the value of W1 / P1 is less than 0.05, the transmittance in the visible light region can be kept high, but the reflectance in the infrared light region is lowered and the effect of heat ray reflection is reduced. When the value of W1 / P1 is larger than 0.40, the reflectance in the infrared light region can be kept high, but the transmittance in the visible light region is lowered and visibility is deteriorated. Both the visible light transmittance and the infrared light reflectance are preferably 50% or more. When used for an automotive window glass, the visible light transmittance is more preferably 70% or more.

  The shape when the metal grid 2 is observed from above the transparent heat ray reflective sheet may be a circular grid, a triangular grid, a hexagonal grid, etc. in addition to the square grid as shown in FIG. The pitch interval and the value of W1 / P1 can be selected as appropriate.

  In addition, the shape of the metal grid 2 in FIG. 1B in the cross-sectional view is not particularly specified, and may be a wedge shape or a shape with a curvature at the top, but increases the reflectivity of the infrared light region. Since at least the metal grating 2 needs to have a large cross-sectional area, a rectangular shape is considered suitable.

  The metal grid 2 can be formed by a method such as vacuum deposition, sputtering, or plating. The metal lattice 2 can be obtained by forming a reflective material film on the smooth surface of the substrate and then patterning the reflective material into a lattice shape. The metal lattice 2 can also be formed by forming a reflective material on a substrate having irregularities by vapor deposition or sputtering with oblique incidence. Alternatively, the metal lattice 2 can be obtained by filling a concave portion with a reflective material by a vacuum deposition method, a sputtering method, a plating method, or the like on a base material that has been previously subjected to a concave lattice patterning process. The patterning process can be performed by a photolithography method, a nanoimprint method, or the like.

  The medium around the metal grid 2 may be air or may be filled with resin or the like. In the case of filling with a resin or the like, the metal lattice side of the transparent heat ray reflective sheet may be bonded to glass or the like using a resin containing an adhesive component.

  Fig.2 (a) is a schematic sectional drawing which shows another form of the transparent heat ray reflective sheet | seat of this invention. Here, a case where the reflective material is arranged in a dot shape at equal intervals will be described. The transparent heat ray reflective sheet shown in FIG. 2A is mainly composed of a base material 1 and metal dots 3 arranged on the base material 1. The metal dots 3 are provided at a predetermined interval (pitch).

  The metal dots 3 are preferably made of a material (reflective material) exhibiting reflectivity with respect to the infrared light region. As the reflective material, Al, In, Sn, Sb, Bi, Cu, Ag, Au, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Pd, Pt Metals such as these, alloys thereof, tin-doped indium oxide (ITO), zinc oxide, tin oxide, niobium-added titanium oxide, ruthenium oxide, iridium oxide, and other conductive oxides can be used. In particular, Al, Al alloy, Ag, and Ag alloy are preferable because of high reflectivity in the infrared light region.

  By setting the interval between the metal dots 3 within a predetermined pitch interval range, the infrared light region can be reflected and the visible light region can be transmitted. Preferably, the pitch interval is 2000 nm or less, the maximum height of the metal dots in the cross-sectional view is 20 nm or more, and the relationship W2 / P2 between the width W2 and the pitch interval P2 in the cross-section is 0.30. It is preferable that it is 0.70 or less. The width W2 and the pitch interval P2 in the cross sectional view are the dimensions in the cross sectional view of the metal dot 3 as shown in FIG.

  If the pitch interval of the metal dots 3 is wider than 2000 nm, the reflectance in the infrared light region is lowered, and the effect of heat ray reflection is reduced. The minimum pitch interval is preferably 100 nm or more. When the pitch interval is narrowed, the transmittance in the visible light region is lowered. Further, if the value of W2 / P2 is less than 0.30, the transmittance in the visible light region can be kept high, but the reflectance in the infrared light region is lowered and the effect of heat ray reflection is reduced. When the value of W2 / P2 is larger than 0.70, the reflectance in the infrared light region can be kept high, but the transmittance in the visible light region is lowered and the visibility is deteriorated. Both the visible light transmittance and the infrared light reflectance are preferably 50% or more. When used for an automotive window glass, the visible light transmittance is more preferably 70% or more.

  The shape when the metal dots 3 are observed from above the transparent heat ray reflective sheet may be hemispherical dots, cylindrical dots, etc., in addition to the square columnar dots as shown in FIG. And the value of W2 / P2 can be selected as appropriate.

  In addition, the cross-sectional shape of the metal dots 3 in FIG. 2B is not particularly specified, and may be a wedge shape or a shape with a curvature at the top, but at least to increase the reflectivity in the infrared light region. Since the cross-sectional area of the metal dots 3 needs to be large, a rectangular shape is considered suitable.

  The metal dots 3 can be formed by a method such as a vacuum deposition method, a sputtering method, or a plating method. The metal dots 3 can be obtained by forming a reflective material film on the smooth surface of the substrate and then patterning the reflective material into dots. Further, the metal dots 3 can also be formed by forming a reflective material on a substrate having irregularities by oblique incidence vapor deposition or sputtering. Further, the metal dots 3 can also be obtained by filling a concave portion with a reflective material by a vacuum deposition method, a sputtering method, a plating method, or the like on a base material that has been previously subjected to a concave dot patterning process. The patterning process can be performed by a photolithography method, a nanoimprint method, or the like.

  The medium around the metal dots 3 may be air or may be filled with resin or the like. When filling with resin etc., you may bond the metal dot side of a transparent heat ray reflective sheet to glass etc. using resin containing an adhesive component.

  FIG. 3 is a schematic cross-sectional view of the heat ray blocking window glass according to the embodiment of the present invention. The heat ray blocking window glass is mainly composed of a plate glass 4 and a transparent heat ray reflective sheet 5 attached on the plate glass 4. That is, the heat ray blocking window glass has a structure in which the transparent heat ray reflective sheet 5 shown in FIG. 1A or 2A is attached to the plate glass 4 through the transparent adhesive layer 6. The surface on which the metal grid 2 or the metal dots 3 are disposed may be bonded so as to be on the plate glass side or may be bonded on the opposite side. When it is bonded to the plate glass side, the metal grid 2 or the metal dots 3 are not exposed, and the shape is protected by the base material 1, which is preferable.

  FIG. 4 is a schematic cross-sectional perspective view showing an example of a multilayer window glass. The multi-layer type window glass is a window glass in which a hollow layer 8 is provided between two plate glasses 41 and 42 by a spacer 7, and each member is fixed by a sealant agent 9 that prevents moisture intrusion and diffusion of internal air. Is done. Thus, heat insulation performance improves by passing the hollow layer 8 between two glass. In this configuration, in order to further improve the heat insulation performance and prevent condensation caused by a temperature difference between the inside and outside of the room, a desiccant is installed in a portion in contact with the hollow layer 8 so that the enclosed air is in a dry state. It is preferable to keep. In this case, a rare gas such as argon gas may be enclosed in the hollow layer 8.

  By sticking a transparent heat ray reflective sheet on one side of this multilayer window glass, visible light from the outside can be transmitted and infrared light can be reflected when it is placed on the window glass of a house or car.

  As described above, according to the present invention, a transparent heat ray reflective sheet having high transparency in the visible light region and high reflectivity in the infrared light region, and a heat ray shielding window glass using the same are obtained. Therefore, the energy required for cooling can be greatly reduced by suppressing the temperature rise in the room or the vehicle. Moreover, a transparent heat ray reflective sheet having a large area can be produced at low cost. Furthermore, since the metal grid | lattice or metal dot which has a function which reflects a heat ray is an inorganic substance, it is excellent in durability with respect to a heat | fever or light.

  Next, examples performed for clarifying the effects of the present invention will be described. In addition, the dimension, material, etc. in the following embodiment are illustrative and can be appropriately selected and implemented. Other modifications can be made without departing from the scope of the present invention.

[Example 1]
In the transparent heat ray reflective sheet shown in FIG. 1 (a), the substrate 1 was a polyethyl terephthalate (PET) film having a thickness of 100 μm, and aluminum was formed to a thickness of about 100 nm by a sputtering method. After that, a photoresist is applied on the aluminum film, and a two-dimensional lattice pattern as shown in FIG. 1A is formed by photolithography, and then reactive dry etching using a chlorine-based gas is performed. This was performed to remove the exposed aluminum from the resist pattern. Finally, the photoresist was dissolved and removed with a chemical solution to obtain a two-dimensional lattice-like aluminum lattice. At this time, the lattice interval (P1) in the cross sectional view of the aluminum lattice was about 200 nm, the lattice width (W1) was about 22 nm, and W1 / P1 = 0.11.

  As a result of measuring the transmittance and reflectance of the obtained transparent heat ray reflective sheet, the visible light transmittance at a wavelength of 500 nm is about 81%, the infrared light reflectance at a wavelength of 1500 nm is about 79%, and exhibits heat insulation performance. It turns out that it has sufficient infrared light reflection performance to do.

  A transparent double-sided pressure-sensitive adhesive film was laminated on the surface of the obtained transparent heat ray reflective sheet on which the aluminum lattice was provided, and bonded to a plate glass. As a result of measuring the transmittance and the reflectance in this state, good visible light transmittance and infrared light reflectance were confirmed although there was a difference of about 3% compared to the state where the plate glass was not bonded.

[Example 2]
In the transparent heat ray reflective sheet shown in FIG. 1 (a), the substrate 1 was a polyethyl terephthalate (PET) film having a thickness of 100 μm, and aluminum was formed to a thickness of about 100 nm by a sputtering method. After that, a photoresist is applied on the aluminum film, and a two-dimensional lattice pattern as shown in FIG. 1A is formed by photolithography, and then reactive dry etching using a chlorine-based gas is performed. This was performed to remove the exposed aluminum from the resist pattern. Finally, the photoresist was dissolved and removed with a chemical solution to obtain a two-dimensional lattice-like aluminum lattice. At this time, the lattice interval (P1) in the cross sectional view of the aluminum lattice was about 600 nm, the lattice width (W1) was about 200 nm, and W1 / P1 = 0.33.

  As a result of measuring the transmittance and reflectance of the obtained transparent heat ray reflective sheet, the visible light transmittance at a wavelength of 500 nm is about 55%, the infrared light reflectance at a wavelength of 1700 nm is about 72%, and exhibits heat insulation performance. It turns out that it has sufficient infrared light reflection performance to do.

  A transparent double-sided pressure-sensitive adhesive film was laminated on the surface of the obtained transparent heat ray reflective sheet on which the aluminum lattice was provided, and bonded to a plate glass. As a result of measuring the transmittance and the reflectance in this state, good visible light transmittance and infrared light reflectance were confirmed although there was a difference of about 3% compared to the state where the plate glass was not bonded.

[Example 3]
In the transparent heat ray reflective sheet shown in FIG. 2A, the base material 1 was a polyethyl terephthalate (PET) film having a thickness of 100 μm, and silver was formed to a thickness of about 40 nm by a sputtering method. Then, after applying a photoresist on the silver film and forming a dot-like pattern as shown in FIG. 2A using a photolithography method, wet etching using a phosphoric acid solution is performed, and the resist The exposed silver from the pattern was removed. Finally, the photoresist was dissolved and removed with a chemical solution to obtain a silver dot pattern. At this time, the dot interval (P2) in the cross sectional view of the silver dots was about 800 nm, the dot width (W2) was about 500 nm, and W2 / P2 = 0.63.

  As a result of measuring the transmittance and reflectance of the obtained transparent heat ray reflective sheet, the visible light transmittance at a wavelength of 500 nm is about 70%, the infrared light reflectance at a wavelength of 1500 nm is about 85%, and exhibits heat insulation performance. It turns out that it has sufficient infrared light reflection performance to do.

  A transparent double-sided pressure-sensitive adhesive film was laminated on the surface of the obtained transparent heat ray reflective sheet on which the silver dot pattern was provided, and bonded to a plate glass. As a result of measuring the transmittance and the reflectance in this state, good visible light transmittance and infrared light reflectance were confirmed although there was a difference of about 3% compared to the state where the plate glass was not bonded.

[Comparative Example 1]
In the transparent heat ray reflective sheet shown in FIG. 1 (a), the substrate 1 was a polyethyl terephthalate (PET) film having a thickness of 100 μm, and aluminum was formed to a thickness of about 100 nm by a sputtering method. After that, a photoresist is applied on the aluminum film, and a two-dimensional lattice pattern as shown in FIG. 1A is formed by photolithography, and then reactive dry etching using a chlorine-based gas is performed. This was performed to remove the exposed aluminum from the resist pattern. Finally, the photoresist was dissolved and removed with a chemical solution to obtain a two-dimensional lattice-like aluminum lattice. At this time, the lattice spacing (P1) in the cross sectional view of the aluminum lattice was about 850 nm, the lattice width (W1) was about 400 nm, and W1 / P1 = 0.47.

  As a result of measuring the transmittance and reflectance of the obtained transparent heat ray reflective sheet, the visible light transmittance at a wavelength of 500 nm is about 20%, the infrared light reflectance at a wavelength of 1500 nm is about 62%, and in the visible light region. It can be seen that the visibility is not excellent.

[Comparative Example 2]
In the transparent heat ray reflective sheet shown in FIG. 2A, the substrate 1 was a polyethyl terephthalate (PET) film having a thickness of 100 μm, and silver was formed to a thickness of about 100 nm by a sputtering method. Then, after applying a photoresist on the silver film and forming a dot-like pattern as shown in FIG. 2A using a photolithography method, wet etching using a phosphoric acid solution is performed, and the resist The exposed silver from the pattern was removed. Finally, the photoresist was dissolved and removed with a chemical solution to obtain a silver dot pattern. At this time, the dot interval (P2) in the cross sectional view of the silver dots was about 2200 nm, the dot width (W2) was about 1600 nm, and W2 / P2 = 0.73.

  As a result of measuring the transmittance and reflectance of the obtained transparent heat ray reflective sheet, the visible light transmittance at a wavelength of 500 nm is about 65%, the infrared light reflectance at a wavelength of 1500 nm is about 25%, and the heat ray reflection performance is It turns out that it is insufficient.

  As described above, the transparent heat ray reflective sheet according to the present invention has high transparency in the visible light region and high reflectivity in the infrared light region. Alternatively, the energy required for cooling can be greatly reduced by suppressing the temperature rise in the vehicle. In addition, a transparent heat ray reflective sheet having a large area can be produced at low cost.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. For example, the dimensions, materials, and the like in the above-described embodiment are illustrative, and can be changed as appropriate. Other modifications can be made without departing from the scope of the present invention.

  According to the transparent heat ray reflective sheet of the present invention, since the visible light transmittance is high and the infrared light reflectance is high, it is suitable for heat ray shielding applications.

DESCRIPTION OF SYMBOLS 1 Base material 2 Metal lattice 3 Metal dot 4,41,42 Plate glass 5 Transparent heat ray reflective sheet 6 Transparent adhesive layer 7 Spacer 8 Hollow layer 9 Sealant agent

Claims (7)

  A transparent heat ray reflective sheet comprising: a base material; and a metal lattice composed of a reflective material arranged at equal intervals in a two-dimensional lattice pattern on the base material, wherein the transparent heat ray reflective sheet is visible A transparent heat ray reflective sheet characterized by having a light transmittance of 50% or more and a maximum reflectance of 50% or more in a wavelength region of a wavelength of 900 nm to 1500 nm.   The pitch interval of the metal grid is 800 nm or less, the maximum height of the metal grid in a cross-sectional view is 20 nm or more, and the relationship W1 / P1 between the width W1 and the pitch interval P1 in the cross-sectional view. 2 or more and 0.40 or less, The transparent heat ray reflective sheet of Claim 1 characterized by the above-mentioned.   A transparent heat ray reflective sheet comprising a base material and metal dots made of a reflective material arranged at equal intervals on the base material, wherein the transparent heat ray reflective sheet has a visible light transmittance of 50. %, And the maximum value of the reflectance is 50% or more in a wavelength region of wavelengths from 900 nm to 1500 nm.   The pitch interval of the metal dots is 2000 nm or less, the maximum height of the metal dots in a cross-sectional view is 20 nm or more, and the relationship W2 / P2 between the width W2 and the pitch interval P2 in the cross-sectional view. It is 0.30 or more and 0.70 or less, The transparent heat ray reflective sheet | seat of Claim 3 characterized by the above-mentioned.   The said reflective material is comprised by what was chosen from the group which consists of aluminum, an aluminum alloy, silver, and a silver alloy, The transparent heat ray reflection in any one of the Claims 1-4 characterized by the above-mentioned. Sheet.   A heat ray shielding window glass comprising: a plate glass; and the transparent heat ray reflective sheet according to any one of claims 1 to 5 attached on the plate glass.   A light beam separation method, wherein visible light and infrared light are separated by irradiating the transparent heat ray reflective sheet according to any one of claims 1 to 6 with all light rays.

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