Heat ray shielding film, and method for producing heat ray shielding film

Abstract

A heat ray shielding film comprising a glass substrate, a first layer, a second layer, and a third layer, wherein: the first layer contains a crystalline tungsten oxide represented by general formula WO3-x (0≤x≤0.28); the second layer contains tungsten bronze; the third layer contains at least one compound selected from the compound group of SiO2, TiO2, WO3, Nb2O5, Al2O3, ZrO2, Ta2O5, SnO2, Si3N4, LaB6and TiN; and the layers are arranged in the order of the first layer, the second layer and the third layer, with the first layer being closest to the glass substrate.

Description

Heat shielding film, method for manufacturing a heat shielding film

[0001] This invention relates to a heat-shielding film and a method for manufacturing a heat-shielding film.

[0002] Sunlight entering through openings such as windows and doors in roofs and walls of various buildings, automobiles, railway cars, aircraft, and ships contains not only visible light but also ultraviolet and infrared rays. Of the infrared rays contained in sunlight, near-infrared rays with wavelengths of 800 nm to 2500 nm are called heat rays, and when they enter a room through openings such as windows, they cause the room temperature to rise. In order to reduce the rise in room temperature caused by heat rays, there has been a surge in demand in recent years for heat-shielding films that have a heat-shielding function that blocks heat rays while allowing sufficient visible light to enter, thereby reducing the rise in room temperature while maintaining brightness, and are used as components for windows of various buildings and vehicles, arcades, ceiling domes, carports, etc.

[0003] Therefore, various studies have been conducted on heat-shielding films.

[0004] For example, Patent Document 1 contains the general formula Cs ｘ W ｙ O ｚ A near-infrared shielding film is disclosed, which is composed of a continuous film of cesium composite tungsten oxide represented by (4.8 ≤ x ≤ 14.6, 20.0 ≤ y ≤ 26.7, 62.2 ≤ z ≤ 71.4, x + y + z = 100), wherein the continuous film includes one or more selected from orthorhombic, rhombohedral, and hexagonal crystal structures.

[0005] Japanese Patent Application Publication No. 2022-038474

[0006] Incidentally, when a heat-shielding film is formed by depositing tungsten bronze on a glass substrate, the haze of the heat-shielding film sometimes becomes high. For use in window materials and the like, a heat-shielding film with low haze is required.

[0007] One aspect of the present invention aims to provide a heat shielding film with low haze.

[0008] A heat-shielding film according to one aspect of the present invention comprises a glass substrate, a first layer, a second layer, and a third layer, wherein the first layer is crystalline and has the general formula WO３－ｘ It contains tungsten oxide represented by (0 ≦ x ≦ 0.28), the second layer contains tungsten bronze, and the third layer contains SiO ２ , TiO ２ , WO ３ , Nb ２ O ５ , Al ２ O ３ , ZrO ２ , Ta ２ O ５ , SnO ２ , Si ３ N ４ , LaB ６ , TiN, and contains one or more selected from the group of compounds, and is arranged in the order of the first layer, the second layer, and the third layer from a position close to the glass substrate.

[0009] According to the heat ray shielding film according to one aspect of the present invention, a heat ray shielding film with low haze can be provided.

[0010] FIG. 1 is an explanatory diagram of a heat ray shielding film according to one aspect of the present disclosure. FIG. 2 is an explanatory diagram of a heat ray shielding film according to another aspect of the present disclosure. FIG. 3 is a flowchart of a method for manufacturing a heat ray shielding film according to one aspect of the present disclosure.

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Heat ray shielding film] FIGS. 1 and 2 show explanatory diagrams of the heat ray shielding film of the present embodiment. FIGS. 1 and 2 are cross-sectional views of the heat ray shielding film of the present embodiment in a plane along the stacking direction of the first layer, the second layer, and the third layer. Since FIG. 2 corresponds to another configuration example of the heat ray shielding film of the present embodiment, the description will be mainly made using FIG. 1, and FIG. 2 will be used for explanation as necessary.

[0012] In this specification, when adding numbers such as first and second to the names of members such as the first layer, the second layer, and the third layer, it is only for specifying the members being described and avoiding confusion, and does not indicate the arrangement, priority, etc.

[0013] As shown in Figure 1, the heat shielding film 10 of this embodiment has a glass substrate 11, a first layer 12, a second layer 13, and a third layer 14. Furthermore, the layers can be arranged in the order of the first layer 12, the second layer 13, and the third layer 14, starting from a position close to the glass substrate 11.

[0014] The layers of the heat shielding film of this embodiment will now be described. (1) About each layer (1-1) Glass substrate The glass substrate 11 is a substrate that supports the first layer 12, the second layer 13, and the third layer 14.

[0015] The type of glass contained in the glass substrate 11 is not particularly limited, and any glass can be used. The glass contained in the glass substrate 11 may be one or more types selected from, for example, soda glass, soda-lime glass, borosilicate glass, aluminosilicate glass, chemically strengthened glass, alkali-free glass, etc. Examples of chemically strengthened glass include alkali aluminosilicate glass containing alkali metal oxides and soda glass containing alkali metal oxides.

[0016] The average thickness T11 of the glass substrate 11 is not particularly limited, but may be, for example, 0.5 mm or more and 50.0 mm or less, or 0.5 mm or more and 1.0 mm or less. (1-2) First layer The inventors of the present invention investigated the cause of high haze in a heat shielding film in which a tungsten bronze film is placed on a glass substrate.

[0017] The investigation revealed that in the heat-shielding film with increased haze, a new phase was formed, likely due to a reaction between components in the tungsten bronze and components in the glass substrate. Therefore, it was inferred that the increased haze in the heat-shielding film was due to the migration and reaction of components in the glass substrate during the deposition of the tungsten bronze film, resulting in the formation of a new compound phase.

[0018] Based on the mechanism by which haze increases in conventional heat shielding films described above, the inventors of the present invention conducted further investigations. As a result, they discovered that by placing a first layer 12 between the glass substrate 11 and the second layer 13 containing a tungsten bronze film, which can reduce the movement of components from the glass substrate 11 to the second layer 13, a heat shielding film 10 with reduced haze can be created, thus completing the present invention.

[0019] Therefore, in the heat shielding film 10 of this embodiment, a first layer 12 can be provided between the glass substrate 11 and the second layer 13. The first layer 12 is a crystalline material of general formula WO ３－ｘ It contains tungsten oxide represented by (0 ≤ x ≤ 0.28). General formula WO ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28) may be included in the first layer 12 as a film containing the tungsten oxide. Below, the general formula WO ３－ｘ Tungsten oxide, expressed as (0 ≤ x ≤ 0.28), is sometimes simply referred to as tungsten oxide. (1-2-1) Regarding the composition of the first layer, the glass used in the glass substrate contains additives to control various properties of the glass, such as the glass transition temperature. According to the inventors' research, elements such as additives contained in the glass mainly used in the glass substrate, such as Group 1 elements like alkali metals and Group 2 elements like alkaline earth metals, react with tungsten bronze, producing a different phase.

[0020] Therefore, in this embodiment, the heat shielding film 10 has a first layer 12 placed between the glass substrate 11 and the second layer 13, preventing elements such as additives contained in the glass from reaching the second layer 13 from the glass substrate 11. As a result, it is possible to prevent the formation of different phases in the second layer 13 and the increase in haze of the heat shielding film.

[0021] The first layer 12 is, as described above, the general formula WO ３－ｘ It can contain tungsten oxide represented by (0 ≤ x ≤ 0.28). Note that the first layer 12 can also be composed solely of tungsten oxide, but this does not exclude the inclusion of unavoidable impurities introduced during the manufacturing process.

[0022] Furthermore, the first layer 12 may also contain a continuous film. In this case, the continuous film may contain tungsten oxide. (Tungsten oxide) Tungsten oxide readily reacts with elements such as alkali metals and alkaline earth metals contained in the glass to form composite tungsten oxide, which is tungsten bronze. For tungsten oxide, it is in stoichiometric ratio WO ３ In that case it is a transparent inert film, but when reduced it becomes WO ３－ｘ Because it has the property of absorbing and reflecting infrared rays when it is incorporated into the composition, it can exert the effect of reducing the infrared transmittance in the heat shielding film. Tungsten oxide has a monoclinic or tetragonal crystal structure, and because it is crystallized, it incorporates elements derived from additives such as alkali metals and alkaline earth metals contained in the glass into the gaps without changing the crystal structure, and does not cause distortion in the surroundings and increase haze. For this reason, when the first layer 12 contains tungsten oxide, it is preferable that at least a portion of the tungsten oxide contained in the first layer 12 is crystallized. The presence of crystallized tungsten oxide in the first layer 12 can be confirmed, for example, by measuring the X-ray diffraction pattern, when a diffraction peak corresponding to tungsten oxide is produced.

[0023] Furthermore, tungsten oxide itself, when x (which indicates the amount of oxygen deficiency) is greater than 0, can generate a sufficient amount of free electrons to enhance the absorption and reflection properties in the near-infrared region, thereby contributing to the effect of reducing infrared transmittance in the heat shielding film.

[0024] General formula for tungsten oxide: WO ３－ｘ It is preferable that x satisfies the condition 0 ≤ x ≤ 0.28.

[0025] As described above, when the first layer 12 contains tungsten oxide, the tungsten oxide can incorporate elements derived from alkali metals and alkaline earth metals contained in the glass into the voids to form a composite tungsten oxide.

[0026] Therefore, when the first layer 12 contains tungsten oxide, the heat shielding film of this embodiment has an X-ray diffraction pattern in which the tungsten oxide phase and M ｘ１ WO ｚ１It is preferable to be able to identify the phase and the tungsten bronze phase.

[0027] The tungsten oxide phase is due to the tungsten oxide contained in the first layer 12. ｘ１ WO ｚ１ The phase is formed by the reaction of tungsten oxide with alkali metals and alkaline earth metals contained in the glass. Therefore, M ｘ１ WO ｚ１ The phase element M is one or more elements selected from alkali metals and alkaline earth metals, and x1 can satisfy 0.01 ≤ x1 < 1. z1 is not particularly limited, but for example, it may satisfy 2.5 ≤ z1 ≤ 3.0.

[0028] Alkali metal elements include Li (lithium), Na (sodium), K (potassium), rubidium (Rb), cesium (Cs), and Fr (francium).

[0029] Alkaline earth metal elements refer to alkaline earth metal elements in a broad sense, and include Be (beryllium), Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), and Ra (radium).

[0030] The tungsten bronze phase is due to the tungsten bronze contained in the second layer.

[0031] When the first layer 12 contains a film containing tungsten oxide, the heat shielding film of this embodiment, in the X-ray diffraction pattern, the phases originating from the first layer 12 and the second layer 13 are the tungsten oxide phase and M ｘ１ WO ｚ１ It may consist only of the phase and the tungsten bronze phase. (1-2-2) Regarding the average thickness of the first layer, the average thickness T12 of the first layer 12 is not particularly limited, but for example, the average thickness of the first layer 12 may be 5 nm or more and 1200 nm or less, 10 nm or more and 1200 nm or less, or 30 nm or more and 600 nm or less.

[0032] By setting the average film thickness of the first layer 12 to 5 nm or more, the amount of components contained in the glass substrate 11 that reach the second layer 13 can be particularly reduced. Therefore, the haze of the heat shielding film 10 in this embodiment can be particularly reduced.

[0033] By setting the average film thickness of the first layer 12 to 1200 nm or less, the coloration of the first layer 12 and the heat shielding film 10 can be reduced, and the visible light transmittance can be increased. In addition, by setting the average film thickness of the first layer 12 to 1200 nm or less, the time required to form the first layer 12 can be shortened, and the productivity of manufacturing the heat shielding film 10 can be increased. (1-3) Second layer (1-3-1) Composition of the second layer The second layer 13 contains tungsten bronze. The tungsten bronze contained in the second layer 13 may be included in the second layer 13 as a tungsten bronze film.

[0034] The second layer 13 is, for example, general formula A ｘ２ W ｙ２ O ｚ２ It may contain tungsten bronze (composite tungsten oxide) represented by general formula A. ｘ２ W ｙ２ O ｚ２ It is also possible to construct it solely from tungsten bronze, but even in this case, it does not eliminate the possibility of unavoidable impurities being introduced during the manufacturing process.

[0035] In the above general formula, it is preferable that x², y², and z² satisfy the following conditions: 0.2 ≤ x² / y² ≤ 0.5 and 2.5 ≤ z² / y² ≤ 3.0.

[0036] Element A may contain one or more alkali metal elements selected from K (potassium), Rb (rubidium), and Cs (cesium). Some of the alkali metal elements contained in element A may be substituted with one or more elements selected from Na (sodium), Tl (thallium), In (indium), Li (lithium), Be (beryllium), Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), Al (aluminum), and Ga (gallium).

[0037] In other words, element A includes one or more alkali metal elements selected from K, Rb, and Cs, and may further include one or more selected from Na, Tl, In, Li, Be, Mg, Ca, Sr, Ba, Al, and Ga as needed. (1-3-2) Regarding the crystal structure, the tungsten bronze contained in the second layer 13, for example, as described in the general formula above, contains element A and oxygen vacancies, which generates a sufficient amount of free electrons to enhance the absorption and reflection characteristics in the near-infrared region and can contribute to the effect of reducing the infrared transmittance in the heat shielding film. For this reason, the crystal structure of tungsten bronze is not particularly limited and can have one or more crystal structures selected from, for example, tetragonal, cubic, hexagonal, and pseudohexagonal. Pseudohexagonal means a structure that deviates from perfect hexagonal symmetry due to defects in the prism plane or bottom plane of the hexagonal crystal. Also, tungsten bronze may contain amorphous parts.

[0038] The absorption position of infrared light tends to change depending on the crystal structure of tungsten bronze. This infrared light absorption position tends to shift to longer wavelengths when the crystal structure is tetragonal compared to cubic, and further to longer wavelengths when the crystal structure is hexagonal. In addition, in conjunction with this variation in absorption position, the absorption of visible light is least in the hexagonal crystal structure, followed by the tetragonal crystal structure, and among these, the absorption of visible light is greatest in the cubic crystal structure. Therefore, for applications that transmit more visible light and shield more infrared light, it is preferable to use tungsten bronze with a hexagonal crystal structure. For this reason, the tungsten bronze contained in the second layer 13 may have, for example, a hexagonal crystal structure. (1-3-3) Regarding film thickness, the average film thickness T13 of the second layer 13 is not particularly limited, but for example, the average film thickness T13 of the second layer 13 may be 5 nm or more and 1200 nm or less, 10 nm or more and 1200 nm or less, or 30 nm or more and 600 nm or less.

[0039] By setting the average film thickness T13 of the second layer 13 to 5 nm or more, the infrared transmittance of the heat shielding film 10 can be particularly reduced, resulting in a heat shielding film with particularly excellent heat shielding properties.

[0040] Furthermore, by setting the average film thickness T13 of the second layer 13 to 1200 nm or less, the coloration of the second layer 13 and the heat shielding film 10 can be reduced, and the visible light transmittance can be increased. Also, by setting the average film thickness T12 of the second layer 13 to 1200 nm or less, the time required to form the second layer 13 can be shortened, and the productivity of manufacturing the heat shielding film 10 can be increased. (1-4) Third layer (1-4-1) Composition of the third layer The heat shielding film 10 of this embodiment may further have a third layer 14 laminated on the second layer 13.

[0041] The third layer 14 may be directly laminated on the second layer 13, or there may be any layer between the second layer 13 and the third layer 14.

[0042] The presence of a third layer 14 in the heat shielding film 10 protects the heat shielding film 10 from the outside world and prevents damage. Depending on the application of the heat shielding film 10, the third layer 14 may also have a function to improve optical properties such as visible light transmittance and infrared region reflectance by adjusting the refractive index.

[0043] Furthermore, because the heat shielding film 10 has a third layer 14, the diffusion of oxygen to the first layer 12 and the second layer 13 can be controlled when heat treatment is performed during the manufacturing process of the heat shielding film 10. For this reason, the heat treatment can be performed in an oxidizing atmosphere such as air. Even when heat treatment is performed in an oxidizing atmosphere such as air, the degree of oxidation of the tungsten bronze in the second layer 13 can be kept within an appropriate range, thereby reducing the haze of the heat shielding film 10.

[0044] The material contained in the third layer 14 is not particularly limited and can be selected according to the application of the heat shielding film 10 and the optical properties required for the heat shielding film 10. For example, the third layer 14 may be SiO ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N４ , LaB ６ , TiN, MgF ２ , HfO ２ , SiO ｘ N ｙ contains one or more selected from the group of compounds of. The third layer 14 is, for example, SiO ２ , TiO ２ , WO ３ , Nb ２ O ５ , Al ２ O ３ , ZrO ２ , Ta ２ O ５ , SnO ２ , Si ３ N ４ , LaB ６ , TiN may contain one or more selected from the group of compounds. For example, SiO contained in the third layer 14 ２ , TiO ２ , WO ３ , Nb ２ O ５ , Al ２ O ３ , ZrO ２ , Ta ２ O ５ , SnO ２ , Si ３ N ４ , LaB ６ , TiN, MgF ２ , HfO ２ , SiO ｘ N ｙ One or more compounds selected from the group of compounds of may be contained in the third layer 14 as a film containing these compounds.

[0045] For example, SiO ２ or, Nb ２ O ５ etc. have high transparency and high dielectric constant, so when using the heat ray shielding film 10 for optical devices, displays, electronic devices, etc., it is preferable to use it as the material of the third layer 14. For example, ZrO ２ or, Si ３ N ４ , Al ２ O ３It is preferable to use the heat shielding film 10 as the material for the third layer 14 when it is used in a device that requires mechanical strength and heat resistance. Also, for example, SnO ２ Yes, LaB ６ It is preferable to use the heat shielding film 10 as the material for the third layer 14 when it is used in applications where transparency, chemical stability, and high conductivity are required. There may be multiple third layers. (1-4-2) Regarding film thickness, the average film thickness T14 of the third layer 14 is not particularly limited, but for example, the average film thickness T14 of the third layer 14 may be 5 nm or more and 1200 nm or less, 10 nm or more and 1200 nm or less, or 30 nm or more and 600 nm or less.

[0046] By setting the average film thickness T14 of the third layer 14 to 5 nm or more, the heat shielding film 10 can be particularly protected, resulting in a heat shielding film with particularly excellent durability.

[0047] Furthermore, by setting the average film thickness T14 of the third layer 14 to 1200 nm or less, the time required to form the third layer 14 can be shortened, thereby increasing the productivity of the manufacturing of the heat shielding film 10. (1-5) Underlying layer Figure 2 shows another configuration example of this embodiment, a heat shielding film 20. As shown in Figure 2, the heat shielding film of this embodiment may have an underlying layer 15 between the glass substrate 11 and the second layer 13.

[0048] Figure 2 shows an example in which the underlayer 15 is placed between the glass substrate 11 and the first layer 12, but the underlayer 15 may also be placed between the first layer 12 and the second layer 13.

[0049] Substrate 15 is made of general formula SiO ａ N ｂIt may contain one or more selected from silicon oxynitride represented by the general formula SiOaNb and aluminum oxide. One or more compounds selected from silicon oxynitride represented by the general formula SiOaNb and aluminum oxide contained in the base layer 15 may be incorporated into the base layer 15 as a film containing these compounds. (1-5-1) Composition of the base layer As explained in "(1-2) First layer", the glass used for the glass substrate contains additives. According to the inventors' research of the present invention, elements such as additives contained in the glass mainly used for the glass substrate, such as Group 1 elements such as alkali metals and Group 2 elements such as alkaline earth metals, react with tungsten bronze to produce a different phase.

[0050] Therefore, the heat shielding film 10 of this embodiment has a first layer 12, which prevents elements such as additives contained in the glass from reaching the second layer 13 from the glass substrate 11. Furthermore, by having an underlayer 15, as in the heat shielding film 20 of this embodiment, it is possible to further reduce the amount of elements such as additives contained in the glass from reaching the second layer 13 from the glass substrate 11. As a result, the presence of the underlayer 15 in the heat shielding film 20 is particularly effective in preventing the formation of different phases in the second layer 13 and increasing the haze of the heat shielding film.

[0051] Silicon oxynitride and aluminum oxide have the function of preventing components in the glass used in the glass substrate 11 from migrating to the second layer 13.

[0052] The general formula for silicon oxynitride is SiO ａ N ｂ In the expression, it is preferable that a and b satisfy 0 ≤ a ≤ 2 and 0 ≤ b ≤ 1.33. (2) Physical properties, etc. The physical properties of the heat shielding film of this embodiment are not particularly limited, but it is preferable that they satisfy the characteristics described below, for example. (2-1) Haze The haze of the heat shielding film of this embodiment is preferably 6.0% or less, and more preferably 0.01% or more and 6.0% or less.

[0053] By reducing the haze of the heat-shielding film of this embodiment to 6.0% or less, particularly clear transparency can be obtained, thereby improving visibility when used in openings such as windows.

[0054] By setting the haze of the heat shielding film of this embodiment to 0.01% or more, the productivity of the heat shielding film can be increased. (2-2) Visible light transmittance The visible light transmittance of the heat shielding film of this embodiment is preferably 20% or more and 90% or less, and more preferably 50% or more and 90% or less.

[0055] By setting the visible light transmittance of the heat shielding film of this embodiment to 20% or more, visibility through the heat shielding film of this embodiment can be improved when used in openings such as window materials. Furthermore, by setting the visible light transmittance of the heat shielding film of this embodiment to 90% or less, the first layer 12, the second layer 13, and the third layer 14 can be made to a sufficient thickness, thereby particularly improving the heat shielding ability and durability of the heat shielding film of this embodiment. (2-3) Solar radiation transmittance The solar radiation transmittance of the heat shielding film of this embodiment is preferably 60% or less, and more preferably 10% or more and 50% or less.

[0056] By setting the solar radiation transmittance of the heat shielding film of this embodiment to 60% or less, the temperature rise on the indoor side can be sufficiently reduced when used in openings such as window materials. By setting the solar radiation transmittance of this embodiment to 10% or more, the productivity of the heat shielding film can be increased. [Method for manufacturing the heat shielding film] Next, an example of the configuration for manufacturing the heat shielding film of this embodiment will be described. According to the method for manufacturing the heat shielding film of this embodiment, a heat shielding film according to one aspect of the present disclosure can be manufactured. For this reason, some explanations of matters already described will be omitted. Note that the method for manufacturing the heat shielding film according to one aspect of the present disclosure is not limited to the following method for manufacturing the heat shielding film.

[0057] The method for manufacturing a heat-shielding film according to this embodiment includes a first layer deposition step, a second layer deposition step, and a third layer deposition step, and may include a deposition step in which a laminate in which the first layer, the second layer, and the third layer are laminated on a glass substrate, and a heat treatment step in which the laminate is heat-treated.

[0058] Then, in the first layer deposition process, a general formula WO is applied to the glass substrate. ３－ｘ A first layer containing tungsten oxide represented by (0 ≤ x ≤ 0.28) can be formed.

[0059] In the second layer deposition process, a second layer containing tungsten bronze can be deposited on the first layer.

[0060] In the third layer deposition process, SiO is deposited on the second layer. ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６ TiN, MgF ２ , HfO ２ SiO ｘ N ｙ A third layer containing one or more compounds selected from the group of compounds can be formed.

[0061] In the heat treatment process, the laminate obtained in the film formation process can be heat-treated in an oxygen-containing atmosphere.

[0062] The manufacturing process for the heat shielding film of this embodiment may include, for example, a first layer deposition step S1, a second layer deposition step S2, a third layer deposition step S3, and a heat treatment step S4, as shown in the flow diagram 30 in Figure 3. However, if the desired heat shielding film can be formed by omitting any of the steps, it is not necessary to go through all of the above steps.

[0063] The following describes each process. (1) Film deposition process In the film deposition process, raw material particles can be attached to the substrate by using, for example, a physical or chemical film deposition method to form a thin film. In the film deposition process, the first, second, and third layers can be deposited using one or more methods selected from, for example, vacuum deposition, sputtering, ion plating, ion beam sputtering, pulsed laser deposition (PLD), and chemical vapor deposition (CVD).

[0064] As for the sputtering method, one or more methods selected from high-frequency sputtering, pulsed sputtering, dual magnetron sputtering, etc., may be used. The materials contained in the first layer 12, the second layer 13, and the third layer 14 have already been described, so the explanation will be omitted. Each layer can be formed by selecting raw materials so as to form a layer with the desired composition according to the film formation method. (1-1) First layer film formation process The first layer film formation process will be described below.

[0065] In the first layer deposition process, the first layer can be deposited on the glass substrate. Since the glass substrate has already been explained, its explanation will be omitted here.

[0066] In the first layer deposition process, the substrate temperature during deposition is not particularly limited, and the process may be carried out at room temperature, i.e., without heating. However, depending on the characteristics required for the first layer or the heat shielding film, the substrate may be heated during the first layer deposition process. For example, if the substrate is heated and sputtering deposition is performed, the first layer will be formed on the substrate while crystal growth occurs. This makes it possible to obtain a first layer film (e.g., a thin film) with uniform crystal orientation. When heating the substrate during the first layer deposition process, the substrate temperature is not particularly limited, and the substrate temperature can be selected according to the composition of the first layer to be deposited, for example.

[0067] In the first layer deposition step, a first layer containing tungsten oxide can be deposited. In the first layer deposition step, a first layer containing a film (e.g., a thin film) containing tungsten oxide may be deposited. (1-2) Second layer deposition step The second layer deposition step will be described below.

[0068] The second layer deposition process can be carried out using the first layer deposited on the glass substrate as the substrate.

[0069] In the second layer deposition process, the substrate temperature during deposition is not particularly limited; for example, the process may be carried out at room temperature, i.e., without heating. However, depending on the characteristics required for the second layer or the heat shielding film, the substrate may be heated during the second layer deposition process.

[0070] In the second layer deposition process, a second layer containing tungsten bronze can be deposited. In the second layer deposition process, a second layer containing a film (e.g., a thin film) containing tungsten bronze may be deposited. (1-3) Third layer deposition process The third layer deposition process will be described below.

[0071] The third layer deposition process can be carried out using the second layer deposited on the glass substrate as the substrate.

[0072] In the third layer deposition process, the substrate temperature during deposition is not particularly limited; for example, the third layer deposition process may be carried out at room temperature, i.e., without heating. However, depending on the characteristics required for the third layer or the heat shielding film, the substrate may be heated during the third layer deposition process.

[0073] In the third layer deposition process, SiO ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６ TiN, MgF ２ , HfO ２ SiO ｘ N ｙ A third layer containing one or more compounds selected from the group of compounds can be formed. In the third layer formation process, SiO ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６A third layer containing one or more compounds selected from the TiN compound group may be formed. In the third layer formation step, a third layer containing a film (e.g., a thin film) containing one or more compounds selected from the above compound group may be formed. (2) Heat treatment step In the heat treatment step, the laminate formed by stacking the first layer 12, second layer 13, and third layer 14 formed in the first layer formation step, second layer formation step, and third layer formation step can be heat treated.

[0074] The atmosphere in the heat treatment process is not particularly limited, but may be selected from, for example, a vacuum atmosphere, an inert gas atmosphere, a reducing gas atmosphere such as hydrogen, and an oxidizing gas atmosphere such as oxygen. However, according to the heat shielding film manufacturing method of this embodiment, the heat treatment process can be carried out after the formation of the third layer 14, and the diffusion of oxygen to the first layer 12 and the second layer 13 can be controlled by the third layer 14. For this reason, the atmosphere in the heat treatment process can be an oxygen-containing atmosphere. The heat treatment process is preferably carried out in an atmospheric atmosphere that can be easily formed and controlled. In the heat treatment process, the heat treatment can be carried out at a heat treatment temperature of, for example, 300°C to 1000°C.

[0075] The heat treatment temperature in the heat treatment process is not particularly limited, but it is preferable to be 1000°C or lower considering the heat resistance of the glass substrate. In particular, the material contained in the first layer 12 may be heat-treated near the phase transition temperature of the desired crystal structure in order to achieve the desired crystal structure.

[0076] The heating rate and heat treatment time in the heat treatment process are not particularly limited, but in order to grow crystals in the first layer 12, it is preferable that the heating rate be 1°C / min or more, and further, after heating to the heat treatment temperature, it is preferable to hold it at the heat treatment temperature for 30 minutes or more. (3) In addition, the method for manufacturing the heat shielding film of this embodiment may also include a base layer formation step as needed.

[0077] The underlayer deposition process can be carried out using the same procedure as the first layer deposition process, except that the material used is appropriate to the material of the underlayer to be deposited.

[0078] The present invention will be described more specifically below with reference to examples, but the present invention is not limited thereto. 1. Evaluation Method (1) X-ray diffraction pattern The X-ray diffraction pattern (XRD pattern) of the obtained heat shielding film was measured using Cu-Kα rays with a D2PHASER X-ray diffractometer from BRUKER AXS. (2) Visible light transmittance, solar transmittance, and maximum reflectance at wavelengths of 780 nm to 2600 nm In measuring the optical properties of the obtained heat shielding film, transmittance and 8° incident diffuse reflectance were measured using a spectrophotometer V-670 (manufactured by JASCO Corp.), and transmittance spectra and reflectance spectra were obtained. Then, using the spectral data of transmittance and reflectance, the visible light transmittance (VLT) and solar transmittance (ST) at wavelengths of 300 nm to 2500 nm were determined in accordance with JIS R 3106 (2019). Furthermore, as an evaluation of reflectance, the maximum reflectance value in the wavelength range of 780 nm to 2600 nm was determined. (3) Haze The haze value was measured using a haze meter (HM-150N manufactured by Murakami Color Technology Laboratory Co., Ltd.) and calculated based on JIS K 7136 (2000). (4) Average film thickness The average film thickness was measured at a total of 5 locations at 1 μm intervals along the surface of the glass substrate in an SEM image taken at any one location in the cross-section of the sample, and the arithmetic mean of these measurements was taken. 2. Manufacturing conditions and evaluation results of the heat shielding film [Example 1] In Example 1, as shown in Figure 1, a heat shielding film was fabricated by sequentially laminating a first layer 12, a second layer 13, and a third layer 14 on a glass substrate 11, and evaluated. (1) Fabrication of heat shielding film (1-1) Fabrication of tungsten oxide target for first layer deposition Tungsten oxide powder was placed in a discharge plasma sintering apparatus (NJS Corporation) under conditions of a vacuum atmosphere, temperature of 870°C, and pressure of 50 MPa to produce a tungsten oxide sintered body. This sintered body was machined to a diameter of 20 mm and a thickness of 4 mm to produce a tungsten oxide target.(1-2) Preparation of a cesium tungsten oxide target for second layer deposition A cesium tungsten oxide powder (YM-01, manufactured by Sumitomo Metal Mining Co., Ltd.) with a Cs / W atomic ratio of 0.33 was introduced into a discharge plasma sintering apparatus (NJS Corporation) under vacuum conditions, a temperature of 870°C, and a pressure of 50 MPa to produce a cesium tungsten oxide sintered body. Chemical analysis of the sintered body composition revealed that the Cs / W ratio, which is the ratio of the amount of substance of Cs to W, was 0.32. This oxide sintered body was machined to a diameter of 20 mm and a thickness of 4 mm to produce a CsWO target.

[0079] Using the above target, a heat shielding film was deposited according to the flow diagram 30 shown in Figure 3. (1-3) First layer deposition process The tungsten oxide target was placed in the vacuum chamber of the pulsed laser deposition apparatus (Pascal PAC-LMBE). The maximum vacuum pressure was 1 × 10⁻⁶ －５ The pressure was kept below Pa, and during film formation, oxygen gas was introduced into the vacuum chamber to achieve a gas pressure of 6.8 Pa, and the first layer 12 was formed on a soda glass substrate.

[0080] A KrF laser (wavelength 248 nm, pulse width 25 ns) was used for irradiation, with a laser power of 150 mJ, a laser frequency of 4 Hz, and a laser irradiation time of 10 minutes. The first layer 12 was deposited under conditions where the substrate heating heater temperature reached 400°C.

[0081] Under the above conditions, in the first layer deposition process, a continuous film of tungsten oxide was deposited on the glass substrate. (1-4) In the second layer deposition process, the target used was replaced with a cesium tungsten oxide target. The maximum vacuum pressure was 1 × 10⁻⁶. －５The vacuum pressure was kept below Pa, and during film deposition, oxygen gas was introduced into the vacuum chamber to achieve a gas pressure of 6.8 Pa for the deposition of the second layer. During film deposition, a KrF laser (wavelength 248 nm, pulse width 25 ns) was used as the irradiation laser, with a laser power of 150 mJ, a laser frequency of 4 Hz, and a laser irradiation time of 10 minutes, under room temperature deposition conditions (no substrate heating). In the first layer deposition process, a continuous film of cesium tungsten oxide was deposited on top of the tungsten oxide film, which was the first layer deposited on the glass substrate. (1-5) In the third layer deposition process, the target used was replaced with an aluminum oxide target. The maximum vacuum pressure was 1 × 10⁻⁶. －５ The pressure was kept below Pa, and during film deposition, oxygen gas was introduced into the vacuum chamber to a gas pressure of 0.5 Pa to deposit the third layer. During film deposition, a KrF laser (wavelength 248 nm, pulse width 25 ns) was used as the irradiation laser, with a laser power of 150 mJ, a laser frequency of 4 Hz, and a laser irradiation time of 10 minutes, under room temperature deposition conditions (no substrate heating). In the second layer deposition process, a continuous aluminum oxide film was deposited on top of the cesium tungsten oxide film, which was the second layer deposited on the glass substrate. (1-6) Heat treatment process After the completion of the third layer deposition process, the introduction of oxygen gas was stopped, and under an atmospheric atmosphere, the substrate heating heater inside the vacuum chamber was heated at a rate of 20°C / min until the substrate reached 500°C, and the temperature was maintained for 30 minutes after heating. After that, the temperature was lowered at a rate of 50°C / min and slowly cooled to room temperature (heat treatment process). (2) Evaluation Results The heat shielding film obtained in Example 1 was evaluated according to the procedure described in "1. Evaluation Method". (2-1) X-ray Diffraction Pattern The X-ray diffraction pattern of the heat shielding film of Example 1 was measured using the measurement method described in "(1) X-ray Diffraction Pattern". Compounds identified from the X-ray diffraction pattern are listed in the "Substances Detected from XRD" column of Table 1.

[0082] As shown in Table 1, the compounds contained in the heat shielding film include tungsten oxide (o-WO) contained in the first layer 12. ３ ) and the Cs contained in the second layer 13 ０．３３ WO ３ It was identified as Cs ０．３３ WO ３Since it was identified, it was confirmed that the third layer suppressed the oxidative degradation of the second layer 13 by atmospheric oxygen. Furthermore, Na ０．０２ WO ２．８ Na was observed. ０．０２ WO ２．８ Na that has moved from the glass substrate 11 is in the WO of the first layer 12. ３ It is thought to have been produced by a reaction with Na. ０．０２ WO ２．８ The Matrix's WO ３ Since it has the same crystal system and nearly equivalent lattice constants, it does not create a large strain field in its surroundings, and therefore does not increase the haze of the heat shielding film 10. Rather, it is thought to have the effect of improving the heat shielding properties.

[0083] The third layer 14 contains Al ２ O ３ Regarding this, no peak was observed because it is amorphous. (2-2) Optical properties As shown in Table 1, the visible light transmittance was 57.75% and the solar transmittance was 30.12%, confirming excellent transmittance in the visible light region and excellent heat shielding properties. In addition, the maximum reflectance value in the wavelength range of 780 nm to 2600 nm was 57.19%, confirming excellent near-infrared reflection properties.

[0084] Furthermore, it was confirmed that the haze was also extremely low at 1.5%. [Example 2] (1) Fabrication of heat shielding film and heat shielding film structure In Example 2, as shown in Figure 2, a heat shielding film was fabricated by laminating a base layer 15, a first layer 12, a second layer 13, and a third layer 14 in order on a glass substrate 11, and was evaluated.

[0085] Specifically, in the underlayer deposition process, an aluminum oxide target was used to deposit the underlayer 15.

[0086] The underlayer film formation process was carried out under the following conditions and procedures.

[0087] An aluminum oxide target was placed inside the vacuum chamber of a pulsed laser deposition system (Pascal PAC-LMBE). The maximum vacuum pressure was 1 × 10⁻¹⁶. －５The pressure was kept below Pa, and during film formation, oxygen gas was introduced into the vacuum chamber to a gas pressure of 0.5 Pa, and the underlayer 15 was formed on a soda glass substrate.

[0088] The irradiation laser used was a KrF laser (wavelength 248 nm, pulse width 25 ns), with a laser power of 150 mJ, a laser frequency of 4 Hz, and a laser irradiation time of 10 minutes, under room temperature film deposition conditions (no substrate heating).

[0089] Under the above conditions, a continuous film of aluminum oxide was deposited on the glass substrate in the underlayer deposition process (underlayer deposition process).

[0090] The first layer deposition process was carried out under the same conditions as in Example 1, except that the first layer was deposited on top of the aluminum oxide film, which was the underlayer deposited on the glass substrate in the underlayer deposition process, instead of using a glass substrate. The second layer deposition process, the third layer deposition process, and the heat treatment process were also carried out under the same conditions as in Example 1 to produce a heat shielding film, so the explanation is omitted. (2) Evaluation results The heat shielding film obtained in Example 2 was evaluated according to the procedure described in "1. Evaluation method". (2-1) X-ray diffraction pattern The X-ray diffraction pattern of the deposited heat shielding film of Example 2 was measured using the measurement method described in "(1) X-ray diffraction pattern". The compounds identified from the X-ray diffraction pattern are listed in the "Substances detected from XRD" column of Table 1.

[0091] As shown in Table 1, the compounds contained in the heat shielding film include tungsten oxide (o-WO) contained in the first layer 12. ３ ) and the Cs contained in the second layer 13 ０．３３ WO ３ And was identified. Furthermore, Na ０．０２ WO ２．８ Na was observed. ０．０２ WO ２．８ Na that has moved from the glass substrate 11 is in the WO of the first layer 12. ３ It is thought to have been produced by a reaction with Na. ０．０２ WO ２．８ The Matrix's WO ３Since it has the same crystal system and nearly equivalent lattice constants, it does not create a large strain field in its surroundings, and therefore does not increase the haze of the heat shielding film 10. Rather, it is thought to have the effect of improving the heat shielding properties.

[0092] Al contained in the base layer 15 and the third layer 14 ２ O ３ Regarding this, no peak was observed because it is amorphous. (2-2) Optical properties As shown in Table 1, the visible light transmittance was 60.42% and the solar transmittance was 36.21%, confirming excellent transmittance in the visible light region and excellent heat shielding properties. In addition, the maximum reflectance value in the wavelength range of 780 nm to 2600 nm was 63.88%, confirming excellent near-infrared reflection properties.

[0093] Furthermore, it was confirmed that the haze was also extremely low at 1.1%. [Comparative Example 1] (1) Preparation of heat shielding film In Comparative Example 1, the third layer deposition process was not performed, and the heat treatment process was performed after the second layer deposition process. Except for the above, the heat shielding film was manufactured under the same conditions and procedures as in Example 1. (2) Evaluation results The heat shielding film obtained in Comparative Example 1 was evaluated according to the procedure described in "1. Evaluation method". (2-1) X-ray diffraction pattern The X-ray diffraction pattern of the deposited heat shielding film of Comparative Example 1 was measured using the measurement method described in "(1) X-ray diffraction pattern". Compounds identified from the X-ray diffraction pattern are listed in the "Substances detected from XRD" column of Table 1.

[0094] As shown in Table 1, the compounds contained in the heat shielding film include o-WO contained in the first layer 12. ３ Besides Na ０．０２ WO ２．８ And, Na ２ W ２ O ７ It was identified.

[0095] o-WO ３ And, Na ０．０２ WO ２．８ And, Na ２ W ２ O ７ This refers to the oxygen in the atmosphere and the components contained in the glass substrate, and the WO contained in the first layer 12. ３and Cs contained in the second layer 13 ０．３３ WO ３ It is thought that it was produced by a reaction between and . Because there is no third layer, oxidation of the second layer proceeds, and Cs ０．３３ WO ３ It is thought that it could not be identified. (2-2) As shown in Optical Properties Table 1, although the visible light transmittance was 86.49%, it was confirmed that the solar transmittance was 81.78%. In addition, it was confirmed that the maximum reflectance in the wavelength range of 780 nm to 2600 nm was 24.42%. In other words, it was confirmed that the heat shielding film of Comparative Example 1 had excellent transmittance in the visible light region, but was inferior in near-infrared reflection characteristics and heat shielding characteristics. In addition, it was confirmed that the haze was high at 9%. The reason for the high haze is that the heat shielding film of Comparative Example 1 does not have a third layer 14, so during heat treatment, oxygen from the atmosphere enters and oxygen-rich Na ２ W ６ O １９ This is thought to be due to the formation of precipitates such as those mentioned above.

[0096]

[0097] Examples of embodiments of the present disclosure are as follows:

[0098] <1> A glass substrate, a first layer, a second layer, and a third layer, wherein the first layer is crystalline and has the general formula WO ３－ｘ The second layer contains tungsten oxide represented by (0 ≤ x ≤ 0.28), the third layer contains tungsten bronze, and the third layer contains SiO ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６ A heat shielding film comprising one or more compounds selected from the TiN group, arranged in the order of the first layer, second layer, and third layer from a position close to the glass substrate.

[0099] <2> The heat shielding film according to <1>, wherein the average thickness of the first layer is 5 nm or more and 1200 nm or less, the average thickness of the second layer is 5 nm or more and 1200 nm or less, and the average thickness of the third layer is 5 nm or more and 1200 nm or less.

[0100] <3> The glass substrate and the second layer have an underlayer, and the underlayer is made of a material of the general formula SiO ａ N ｂ A heat shielding film according to <1> or <2>, comprising silicon oxynitride represented by and one or more selected from aluminum oxide.

[0101] <4> A heat-shielding film according to any one of <1> to <3>, wherein the haze is 0.01% or more and 6.0% or less.

[0102] <5> A heat-shielding film according to any of <1> to <4>, wherein the visible light transmittance is 20% or more and 90% or less.

[0103] <6> A heat-shielding film according to any of <1> to <5>, having a solar transmittance of 60% or less.

[0104] <7> A film formation step comprising a first layer formation step, a second layer formation step, and a third layer formation step, wherein a laminate is formed on a glass substrate in which the first layer, the second layer, and the third layer are laminated, and a heat treatment step is performed to heat treat the laminate, wherein in the first layer formation step, a film of general formula WO is formed on the glass substrate. ３－ｘ A first layer containing tungsten oxide represented by (0 ≤ x ≤ 0.28) is formed in the second layer formation step, a second layer containing tungsten bronze is formed on the first layer in the third layer formation step, and SiO is formed on the second layer ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６A method for manufacturing a heat-shielding film, comprising: forming a third layer containing one or more compounds selected from the TiN group; and in the heat treatment step, heat-treating the laminate in an oxygen-containing atmosphere.

[0105] <8> The method for manufacturing a heat shielding film according to <7>, wherein in the film formation step, the first layer, the second layer, and the third layer are formed using one or more methods selected from vacuum deposition, sputtering, ion plating, ion beam sputtering, pulsed laser deposition (PLD), and chemical vapor deposition (CVD).

[0106] <9> The method for manufacturing a heat shielding film according to <7> or <8>, wherein the heat treatment step is performed at a heat treatment temperature of 300°C or more and 1000°C or less.

[0107] This application claims priority based on Japanese Patent Application No. 2024-184470, filed with the Japan Patent Office on 18 October 2024, and the entire contents of Japanese Patent Application No. 2024-184470 are incorporated herein by reference.

[0108] 10 Heat-shielding film 20 Heat-shielding film 11 Glass substrate 12 First layer T12 Average film thickness 13 Second layer T13 Average film thickness 14 Third layer 15 Underlayer 30 Flowchart S1 First layer deposition process S2 Second layer deposition process S3 Third layer deposition process S4 Heat treatment process

Claims

1. It has a glass substrate, a first layer, a second layer, and a third layer. The first layer contains tungsten oxide represented by the general formula WO ３－ｘ (0 ≤ x ≤ 0.28). The second layer contains tungsten bronze. The third layer contains one or more selected from the group of compounds of SiO ２ , TiO ２ , WO ３ , Nb ２ O ５ , Al ２ O ３ , ZrO ２ , Ta ２ O ５ , SnO ２ , Si ３ N ４ , LaB ６ , TiN. The heat ray shielding film is arranged in the order of the first layer, the second layer, and the third layer from a position close to the glass substrate.

2. The heat shielding film according to claim 1, wherein the average thickness of the first layer is 5 nm or more and 1200 nm or less, the average thickness of the second layer is 5 nm or more and 1200 nm or less, and the average thickness of the third layer is 5 nm or more and 1200 nm or less.

3. The glass substrate and the second layer have an underlayer, the underlayer being of the general formula SiO ａ N ｂ A heat shielding film according to claim 1 or claim 2, comprising one or more selected from silicon oxynitride and aluminum oxide.

4. The heat shielding film according to any one of claims 1 to 3, wherein the haze is 0.01% or more and 6.0% or less.

5. A heat-shielding film according to any one of claims 1 to 4, wherein the visible light transmittance is 20% or more and 90% or less.

6. A heat-shielding film according to any one of claims 1 to 5, wherein the solar radiation transmittance is 60% or less.

7. A film formation process comprising a first layer formation process, a second layer formation process, and a third layer formation process, wherein a laminate is formed on a glass substrate in which the first layer, the second layer, and the third layer are laminated, and a heat treatment process is performed on the laminate, wherein in the first layer formation process, a film of the general formula WO is formed on the glass substrate. ３－ｘ A first layer containing tungsten oxide represented by (0 ≤ x ≤ 0.28) is formed in the second layer formation step, a second layer containing tungsten bronze is formed on the first layer in the third layer formation step, and SiO is formed on the second layer ２ , TiO ２ WO ３ Nb ２ O ５ Al ２ O ３ , ZrO ２ Ta ２ O ５ , SnO ２ Si ３ N ４ LaB ６ A method for manufacturing a heat-shielding film, comprising: forming a third layer containing one or more compounds selected from the TiN group; and in the heat treatment step, heat-treating the laminate in an oxygen-containing atmosphere.

8. The method for manufacturing a heat shielding film according to claim 7, wherein in the film formation step, the first layer, the second layer, and the third layer are formed using one or more methods selected from vacuum deposition, sputtering, ion plating, ion beam sputtering, pulsed laser deposition (PLD), and chemical vapor deposition (CVD).

9. The method for manufacturing a heat shielding film according to claim 7 or claim 8, wherein the heat treatment step is performed at a heat treatment temperature of 300°C or more and 1000°C or less.

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