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, and a second layer, wherein: the first layer contains at least one substance selected from tungsten oxides represented by general formula WO3-x (0≤x≤0.28), silicon oxynitrides represented by general formula SiOaNb, and aluminum oxide; the second layer contains tungsten bronze; and the layers are arranged in the order of the first layer and the second 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, and a second layer, wherein the first layer is of the general formula WO ３－ｘTungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂ The material comprises one or more selected from silicon oxynitride and aluminum oxide, the second layer comprising a tungsten bronze film, and the first layer and the second layer are arranged in that order from a position close to the glass substrate.

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

[0010] Figure 1 is an explanatory diagram of a heat-shielding film according to one aspect of the present disclosure. Figure 2 is an explanatory diagram of a heat-shielding film according to another aspect of the present disclosure. Figure 3 is an explanatory diagram of a heat-shielding film according to another aspect of the present disclosure. Figure 4 is a flowchart of a method for manufacturing a heat-shielding film according to one aspect of the present disclosure.

[0011] The embodiments for carrying out the present invention will be described below with reference to the drawings, but the present invention is not limited to the embodiments described below, and various modifications and substitutions can be made to the embodiments described below without departing from the scope of the present invention. [Heat Shielding Film] Figures 1 to 3 show explanatory diagrams of the heat shielding film of this embodiment. Figures 1 to 3 are cross-sectional views of the first and second layers of the heat shielding film of this embodiment in a plane along the lamination direction. Figures 2 and 3 represent other configuration examples of the heat shielding film of this embodiment, so the explanation will mainly use Figure 1, and use Figures 2 and 3 as necessary.

[0012] In this specification, the names of components may be prefixed with "1st," "2nd," etc., such as "1st layer" and "2nd layer." However, this is merely to identify the component being described and to avoid confusion, and does not indicate its arrangement, priority, or anything of the sort.

[0013] As shown in Figure 1, the heat shielding film 10 of this embodiment has a glass substrate 11, a first layer 12, and a second layer 13. The first layer 12 and the second layer 13 can be arranged in that order, 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 and the second layer 13.

[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 ray shielding film 10 of the present embodiment, a first layer 12 can be provided between the glass substrate 11 and the second layer 13. That is, in this case, the first layer 12 is disposed close to the surface of the glass substrate 11. Particularly in the present embodiment, the first layer 12 is disposed closer to the glass substrate 11 than the second layer 13. And the first layer 12 has tungsten oxide represented by the general formula WO ３－ｘ (0 ≤ x ≤ 0.28), silicon oxynitride represented by the general formula SiO ａ N ｂ and contains one or more selected from aluminum oxide. Tungsten oxide represented by the general formula WO ３－ｘ (0 ≤ x ≤ 0.28), silicon oxynitride represented by the general formula SiO ａ N ｂ and one or more compounds selected from aluminum oxide may be contained in the first layer 12 as a film containing the selected compound. Hereinafter, tungsten oxide represented by the general formula WO ３－ｘ (0 ≤ x ≤ 0.28) and silicon oxynitride represented by the general formula SiO ａ N ｂ may sometimes be simply referred to as tungsten oxide and silicon oxynitride, respectively. (1-2-1) Regarding the composition of the first layer, the glass used for the glass substrate contains additives for controlling various properties of the glass such as the glass transition point. According to the study of the inventor of the present invention, elements such as additives contained mainly in the glass used for the glass substrate, for example, Group 1 elements such as alkali metals and Group 2 elements such as alkaline earth metals react with tungsten bronzes, resulting in the formation of heterogeneous phases.

[0020] Therefore, in the heat ray shielding film 10 of the present embodiment, the first layer 12 is disposed between the glass substrate 11 and the second layer 13, preventing elements such as additives contained in the glass from the glass substrate 11 from reaching the second layer 13. For this reason, heterogeneous phases are generated in the second layer 13, and it is possible to prevent an increase in the haze of the heat ray shielding film.

[0021] As described above, the first layer 12 has tungsten oxide represented by the general formula WO ３－ｘ (0 ≤ x ≤ 0.28), silicon oxynitride represented by the general formula SiO ａ N ｂSilicon oxynitride and aluminum oxide (Al ２ O ３ It may contain one or more selected from the following. The first layer 12 may also consist of only one or more selected from tungsten oxide, silicon oxynitride, and aluminum 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 one or more selected from tungsten oxide, silicon oxynitride, and aluminum 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 WO2 in stoichiometric ratio. 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 ｚ１ It 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 ｚ１It may consist only of the phase and the tungsten bronze phase. (Silicon oxynitride, aluminum oxide) Silicon oxynitride and aluminum oxide have the function of preventing components in the glass used in the glass substrate 11 from moving to the second layer 13.

[0032] 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. (1-2-2) Structure of the first layer As shown in Figure 1, the first layer 12 of the heat shielding film 10 of this embodiment can also be composed of a single film. In this case, the first layer 12 can contain one or more films selected from, for example, a tungsten oxide film, a silicon oxynitride film, and an aluminum oxide film.

[0033] As shown in Figure 2, the first layer 12 of the heat shielding film 20 of this embodiment may have a first film 121 containing one or more selected from, for example, silicon oxynitride or aluminum oxide, and a second film 122 containing tungsten oxide. In Figure 2, the first film 121 and the second film 122 are arranged in order from a position close to the glass substrate 11, but the embodiment is not limited to this. The second film 122 and the first film 121 may be arranged in order from a position close to the glass substrate 11. In addition, the first film 121 and the second film 122 may be arranged alternately or continuously so that there are two or more layers of each. (1-2-3) Average film thickness of the first layer The average film thickness T12 of the first layer 12 is not particularly limited, but for example, the average film 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.

[0034] 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.

[0035] 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 incorporated into the second layer 13 as a tungsten bronze film.

[0036] 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, as represented by [the formula], but even in this case, it does not eliminate the possibility of unavoidable impurities being introduced during the manufacturing process.

[0037] 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.

[0038] 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).

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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) Protective layer Figure 3 shows a heat shielding film 30, which is another example of the configuration of this embodiment. The heat shielding film of this embodiment may further have a protective layer 14 laminated on the second layer 13, as shown in the heat shielding film 30 in Figure 3. When the heat shielding film 30 has a protective layer 14, as shown in Figure 3, the first layer 12, the second layer 13, and the protective layer 14 can be laminated in that order from a position close to the glass substrate 11.

[0043] The protective layer 14 may be directly laminated on the second layer 13, or there may be any layer between the second layer 13 and the protective layer 14.

[0044] The presence of a protective layer 14 in the heat shielding film 30 protects the heat shielding film 30 from the outside world and prevents damage. Depending on the application of the heat shielding film 30, the protective 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. There may be multiple protective layers 14.

[0045] The material contained in the protective layer 14 is not particularly limited and can be selected according to the application of the heat shielding film 30 and the optical properties required for the heat shielding film 30. For example, the protective 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 N ４ LaB ６ TiN, MgF ２ , HfO ２ SiO ｘ N ｙIt may contain one or more compounds selected from the group of compounds. The protective 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 It may also contain one or more compounds selected from the group of TiN compounds.

[0046] For example, SiO ２ Yes, Nb ２ O ５ Because these materials have high transparency and high dielectric constant, it is preferable to use the heat shielding film 30 as a material for the protective layer 14 when it is used in optical devices, displays, electronic devices, etc. For example, ZrO ２ Yes, Si ３ N ４ Al ２ O ３ For example, it is preferable to use the heat shielding film 30 as the material for the protective layer 14 when it is used in a device that requires mechanical strength and heat resistance. ２ Yes, LaB ６ It is preferable to use the heat shielding film 30 as the material for the protective layer 14 when it is used in applications where transparency, chemical stability, and high conductivity are required. (2) Physical properties, etc. The physical properties of the heat shielding film of this embodiment are not particularly limited, but it is preferable that it satisfies the following characteristics, 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.

[0047] 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.

[0048] 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.

[0049] 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 and the second layer 13 can be made to a sufficient thickness, and the heat shielding ability of the heat shielding film of this embodiment can be particularly enhanced. (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.

[0050] 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.

[0051] The method for manufacturing the heat-shielding film of this embodiment may include a film formation step comprising a first layer formation step and a second layer formation step.

[0052] Then, in the first layer deposition process, a general formula WO is applied to the glass substrate. ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂ A first layer can be formed containing one or more selected from silicon oxynitride and aluminum oxide.

[0053] In the second layer deposition process, a second layer containing tungsten bronze can be deposited on the first layer.

[0054] The method for manufacturing the heat-shielding film of this embodiment may further include a heat treatment step in which the layer formed in the film formation step is heat-treated.

[0055] The manufacturing method for the heat-shielding film of this embodiment may include, for example, a first layer formation step S1 and a second layer formation step S2, as shown in the flow diagram 40 in Figure 4. The manufacturing method for the heat-shielding film of this embodiment may also include a heat treatment step S3 after the second layer formation step S2, as shown in the flow diagram 40.

[0056] Furthermore, the manufacturing process for the heat-shielding film in this embodiment may also include a film formation step and a heat treatment step for each of the first and second layers. For this reason, instead of the heat treatment step S3, a first layer heat treatment step may be included between the first layer film formation step S1 and the second layer film formation step S2, and a second layer heat treatment step may be included after the second layer film formation step. 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.

[0057] 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 film (e.g., a thin film). In the film deposition process, the first and second 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).

[0058] As for the sputtering method, one or more methods selected from high-frequency sputtering, pulsed sputtering, dual magnetron sputtering, etc. may be used. (1-1) First layer deposition process The first layer deposition process will be described below.

[0059] 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.

[0060] 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.

[0061] In the first layer deposition step, a first layer containing one or more selected from tungsten oxide, silicon oxynitride, and aluminum oxide can be deposited. In the first layer deposition step, a first layer containing a film (e.g., a thin film) containing one or more selected from tungsten oxide, silicon oxynitride, and aluminum oxide may be deposited.

[0062] The manufacturing process of the glass substrate can also include a first layer deposition process and a second layer deposition process. For example, when manufacturing a glass substrate by the float process, the first layer deposition process and the second layer deposition process can be carried out by sequentially supplying the raw materials for the first layer and the raw materials for the second layer onto the surface of the float glass that has been formed in the float tank and removed. Since the glass plate is at a sufficiently high temperature immediately after being removed from the float tank, a heat treatment process will also be carried out at the same time as the deposition process. (1-2) Second Layer Deposition Process The second layer deposition process will now be explained.

[0063] The second layer deposition process can be carried out using the first layer deposited on the glass substrate as the substrate.

[0064] 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.

[0065] 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. (2) Heat treatment process In the heat treatment process, the first layer and the second layer film deposited in the first layer deposition process and the second layer film deposition process can be heat treated. The heat treatment process may be carried out individually for the first layer and the second layer, or it may be carried out together. When the heat treatment of the first layer and the second layer is carried out together after the second layer deposition process, it may be carried out, for example, under the conditions described in the second layer heat treatment process below.

[0066] The atmosphere in the heat treatment process is not particularly limited, but it is preferably a non-oxidizing atmosphere, and may be selected from, for example, a vacuum atmosphere, an inert gas atmosphere, and a reducing gas atmosphere such as hydrogen. In the heat treatment process, the heat treatment can be carried out at a heat treatment temperature of 300°C to 1000°C under the above atmosphere. (2-1) First layer heat treatment process The first layer heat treatment process will be described below.

[0067] The atmosphere for the first layer heat treatment process is not particularly limited, but may be selected from, for example, a vacuum atmosphere, an inert gas atmosphere, and a reducing gas atmosphere such as hydrogen.

[0068] For the inert gas, for example, noble gases such as helium or argon, or nitrogen gas can be used, but argon gas is preferable because it is commonly used, readily available, and reduces the generation of by-products.

[0069] To avoid contamination with impurities, the purity of the gas used in the first layer heat treatment step is preferably 99% or higher. Furthermore, it is preferable to select the type and ratio of the gas atmosphere in order to control the degree of oxidation-reduction based on the amount of oxygen deficiency in the target product.

[0070] The heat treatment temperature in the first layer heat treatment process is not particularly limited, but it is preferably 1000°C or lower considering the heat resistance of the glass substrate. In particular, the material contained in the first layer may be heat-treated near the phase transition temperature of the desired crystal structure in order to achieve the desired crystal structure.

[0071] While there are no particular limitations on the heating rate and heat treatment time in the first layer heat treatment process, it is preferable that the heating rate be 1°C / min or more in order to promote crystal growth in the first layer, and furthermore, it is preferable to maintain the temperature at the heat treatment temperature for 30 minutes or more after it has been raised to the heat treatment temperature.

[0072] In the film formation process, if the substrate heating temperature is high and the crystals of the first layer are growing, this heat treatment step may be omitted. (2-2) Second layer heat treatment step The second layer heat treatment step will now be described.

[0073] The atmosphere in the second heat treatment process is not particularly limited, but may be selected from, for example, a vacuum atmosphere, an inert gas atmosphere, and a reducing gas atmosphere such as hydrogen.

[0074] For the inert gas, for example, noble gases such as helium or argon, or nitrogen gas can be used, but argon gas is preferable because it is commonly used, readily available, and reduces the generation of by-products.

[0075] To avoid contamination with impurities, the purity of the gas used in the second heat treatment step is preferably 99% or higher. Furthermore, it is preferable to select the type and ratio of the gas atmosphere in order to control the degree of oxidation-reduction depending on the composition of the target product, the amount of oxygen deficiency, etc.

[0076] In the second layer heat treatment process, the heat treatment temperature is not particularly limited, but it is preferably between 300°C and 1000°C. By setting the heat treatment temperature to 300°C or higher, crystallization can be promoted and the transparency of the film can be improved.

[0077] While there are no particular limitations on the heating rate and heat treatment time in the second layer heat treatment process, it is preferable that the heating rate be 1°C / min or more in order to promote crystal growth in the second layer, and further preferable that the temperature be maintained at the heat treatment temperature for 30 minutes or more after reaching the heat treatment temperature.

[0078] If the desired second layer has already been obtained in the film formation process, this heat treatment step may be omitted. (3) The method for manufacturing the heat shielding film of this embodiment may also include a protective layer formation step and a protective layer heat treatment step as needed.

[0079] The protective layer deposition process can be carried out using the same procedure as the first layer deposition process, except that the material used is appropriate for the material of the protective layer to be deposited.

[0080] Furthermore, regarding the protective layer heat treatment process, although the heat treatment conditions can be selected according to the composition of the protective layer, etc., it can be carried out using the same procedure as described in the first layer heat treatment process, for example. Note that the protective layer does not need to be crystallized, so the protective layer heat treatment process does not need to be performed, and the heat treatment may be carried out at a lower temperature than the first layer heat treatment process, etc.

[0081] The present invention will be described in more detail 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, solar heat gain coefficient, and maximum value of reflectance at wavelengths of 780 nm to 2600 nm In measuring the optical properties of the obtained heat shielding film, the transmittance and 8° incident diffuse reflectance were measured using a spectrophotometer V-670 (manufactured by JASCO Corp.), and the transmittance spectrum and reflectance spectrum were obtained. Then, using the spectral data of transmittance and reflectance, the visible light transmittance (VLT), solar radiation transmittance (ST) for wavelengths between 300 nm and 2500 nm, and solar heat gain coefficient (η) were determined in accordance with JIS R 3106 (2019). In addition, as an evaluation of reflectance, the maximum reflectance value for wavelengths between 780 nm and 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 on the cross-section of the sample, and the arithmetic mean was taken. 2. Manufacturing conditions and evaluation results of 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 and a second layer 13 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 the conditions of a vacuum atmosphere, a temperature of 870°C, and a 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.

[0082] Using the above target, a heat shielding film was deposited according to the flow diagram 40 shown in Figure 4. (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 deposition, oxygen gas was introduced into the vacuum chamber to achieve a gas pressure of 6.8 Pa to deposit the first layer.

[0083] During film deposition, a KrF laser (wavelength 248 nm, pulse width 25 ns) was used for irradiation, with an exposure laser power of 150 mJ, a laser frequency of 4 Hz, and a laser irradiation time of 10 minutes. The heater temperature for substrate heating was set to 400°C.

[0084] Under the above conditions, a continuous tungsten oxide film was deposited on a soda glass substrate in the first layer deposition process (first layer deposition process).

[0085] (1-4) In the second layer deposition process and the heat treatment process, the target used was replaced with a cesium tungsten oxide target. The maximum vacuum pressure was 1 × 10⁻⁶. －５It was set to Pa or less, and during film formation, oxygen gas was introduced into the vacuum chamber so that the gas pressure became 6.8 Pa to form the second layer. During film formation, a KrF laser (wavelength 248 nm, pulse width 25 ns) was used as the irradiation laser, the exposure laser power was 150 mJ, the laser frequency was 4 Hz, and the laser irradiation time was 10 minutes. Under the condition of room temperature film formation (without substrate heating), in the first layer film formation process, a continuous film of cesium tungstate was further formed on the tungsten oxide film which was the first layer formed on the soda glass substrate (second layer film formation process).

[0086] After the completion of the second layer film formation process, the introduction of oxygen gas was stopped, and in a vacuum atmosphere, the substrate heating heater inside the vacuum chamber was heated at 20 °C / min so that the substrate reached 500 °C, and after implementing a heat treatment process of holding for 30 minutes after the temperature rise, it was gradually cooled to room temperature at 50 °C / min (heat treatment process). (2) Regarding the evaluation results, the heat ray shielding film obtained in Example 1 was evaluated according to the procedure described in "1. Evaluation method". (2-1) X-ray diffraction pattern For the heat ray shielding film of Example 1 formed, the X-ray diffraction pattern was measured by the measurement method described in "(1) X-ray diffraction pattern". The compounds identified from the X-ray diffraction pattern are described in the column of "Substances detected from XRD" in Table 1.

[0087] As shown in Table 1, as the compounds contained in the heat ray shielding film, tungsten oxide (o-WO ３ ) contained in the first layer 12 and Cs ０．３３ WO ３ contained in the second layer 13 were identified. Further, Na ０．０２ WO ２．８ was observed. It is considered that Na ０．０２ WO ２．８ was generated by the reaction of Na that migrated from the glass substrate 11 with WO ３ in the first layer 12. Na ０．０２ WO ２．８Since it is a compound of tungsten bronze, it is considered that it does not increase the haze of the heat ray shielding film 10, but rather has the effect of enhancing the heat ray shielding property. (2-2) As shown in Table 1 of the optical properties, the visible light transmittance is 53.56% and the solar radiation transmittance is 24.49%, confirming that it is excellent in the permeability in the visible light region and the heat ray shielding property. The maximum value of the reflectance at wavelengths of 780 nm to 2600 nm is 59.07% and the solar heat gain factor is 0.44, confirming that it has excellent reflection characteristics in the near infrared region and is also excellent in the heat ray shielding property.

[0088] Also, it was confirmed that the haze was extremely low at 1.15%. [Example 2] (1) Production of heat ray shielding film and heat ray shielding film structure In Example 2, as shown in FIG. 2, a heat ray shielding film in which a first layer 12 and a second layer 13 were sequentially laminated on a glass substrate 11 was produced and evaluated. Regarding the first layer 12, it was made into a layer having a first film 121 and a second film 122.

[0089] Specifically, in the first layer film formation step, after forming the first film 121 using an aluminum oxide target, the second film 122 was formed using a tungsten oxide target in the same manner as in Example 1.

[0090] Except for the above points, each layer was formed under the same conditions as in Example 1 to have the average film thickness shown in Table 1, and a heat ray shielding film was produced. (2) Regarding the evaluation results The heat ray shielding film obtained in Example 2 was evaluated according to the procedure described in "1. Evaluation method". (2-1) X-ray diffraction pattern Regarding the heat ray shielding film formed in Example 2, the X-ray diffraction pattern was measured by the measurement method described in "(1) X-ray diffraction pattern". The compounds identified from the X-ray diffraction pattern are described in the column of "Substances detected from XRD" in Table 1.

[0091] As shown in Table 1, as the compounds contained in the heat ray shielding film, tungsten oxide (o-WO ３ ) contained in the second film 122 of the first layer 12, and Cs ０．３３ WO ３ contained in the second layer 13 were identified. Further, Na ０．０２ WO ２．８ was observed. Na ０．０２WO 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 Since it is a tungsten bronze compound, it does not increase the haze of the heat shielding film 10, and is rather thought to have the effect of improving the heat shielding properties.

[0092] Al contained in the first film 121 of the first layer 12 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 52.55% and the solar transmittance was 23.57%, confirming excellent transmittance in the visible light region. The maximum reflectance value at wavelengths of 780 nm to 2600 nm was 66.60%, and the solar heat gain coefficient was 0.47, confirming that it has excellent reflective properties in the near-infrared region and also excellent heat shielding properties.

[0093] Furthermore, it was confirmed that the haze was also extremely low at 1.2%. [Example 3] (1) Fabrication of heat shielding film and heat shielding film structure In Example 3, as shown in Figure 1, a heat shielding film was fabricated by sequentially laminating a first layer 12 and a second layer 13 on a glass substrate 11 and evaluated.

[0094] Specifically, in the first layer deposition process, a silicon oxynitride target was used instead of a tungsten oxide target to deposit the first layer 12.

[0095] Except for the points mentioned above, each layer was deposited under the same conditions as in Example 1 to achieve the film thickness shown in Table 1, and a heat shielding film was prepared. (2) Evaluation results The heat shielding film obtained in Example 3 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 3 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.

[0096] As shown in Table 1, the compounds contained in the heat shielding film include Cs contained in the second layer 13.０．３３ WO ３ It was identified.

[0097] No peak was observed for the silicon oxynitride contained in the first layer 12 because it is amorphous.

[0098] Furthermore, the Na observed in Examples 1 and 2 was ０．０２ WO ２．８ This was not observed. This is thought to be because the first layer 12 does not contain tungsten oxide and the first layer 12 containing silicon oxynitride prevents components from migrating from the glass substrate 11. (2-2) Optical properties As shown in Table 1, the visible light transmittance was 73.30% and the solar transmittance was 47.97%, confirming that it has excellent transmittance in the visible light region and excellent heat shielding properties. The maximum reflectance value at wavelengths of 780 nm to 2600 nm was 54.27%, and the solar heat gain coefficient was 0.55, confirming that it has excellent reflectivity in the near-infrared region and also excellent heat shielding properties.

[0099] Furthermore, it was confirmed that the haze was also extremely low at 2.7%. [Comparative Example 1] (1) Preparation of heat shielding film In Comparative Example 1, only the second layer deposition process and the heat treatment process were carried out, and the second layer containing tungsten bronze was directly deposited on the soda glass substrate. 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". The compounds identified from the X-ray diffraction pattern are listed in the "Substances detected from XRD" column of Table 1.

[0100] As shown in Table 1, the compounds contained in the heat shielding film include Cs contained in the second layer 13. ０．３３ WO ３ Besides Na ０．０２ WO ２．８ And, Na ２ W ２ O ７ It was identified.

[0101] Na ０．０２WO ２．８ And, Na ２ W ２ O ７ This refers to the components contained in the glass substrate and the Cs contained in the second layer 13. ０．３３ WO ３ It is thought that the following reacted to produce it. (2-2) Optical properties As shown in Table 1, the visible light transmittance was 73.06% and the solar transmittance was 51.02%, indicating excellent transmittance in the visible light region. However, the maximum reflectance at wavelengths of 780 nm to 2600 nm was 44.31%, and the solar heat gain coefficient was 0.61, confirming that the reflective properties had deteriorated and the heat shielding effect had weakened. It was also confirmed that the haze was high at 7.7%. The decrease in reflectance and increase in haze is due to the fact that the heat shielding film of Comparative Example 1 does not have the first layer 12, so the glass substrate 11 and the tungsten bronze contained in the second layer 13 reacted, and the Na produced by this reaction ２ W ２ O ７ This is thought to be due to products such as those mentioned above.

[0102]

[0103] Examples of embodiments of the present disclosure are as follows:

[0104] <1> It has a glass substrate, a first layer, and a second layer, wherein the first layer is of the general formula WO ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂ A heat shielding film comprising one or more selected from silicon oxynitride and aluminum oxide, wherein the second layer comprises tungsten bronze, and the first layer and the second layer are arranged in that order from a position close to the glass substrate.

[0105] <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, and the average thickness of the second layer is 5 nm or more and 1200 nm or less.

[0106] <3> The heat shielding film according to <1> or <2>, wherein the first layer contains tungsten oxide, and at least a portion of the tungsten oxide is crystallized.

[0107] <4> The first layer contains the tungsten oxide, and the heat shielding film, in the X-ray diffraction pattern, has a tungsten oxide phase and M ｘ１ WO ｚ１ A heat shielding film according to any one of <1> to <3>, wherein a phase (where element M is one or more elements selected from alkali metals and alkaline earth metals, and x1 satisfies 0.01 ≤ x1 < 1) and a tungsten bronze phase are confirmed.

[0108] <5> The heat shielding film according to any one of <1> to <4>, further comprising a protective layer laminated on the second layer.

[0109] <6> The protective layer is 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 The heat shielding film according to <5>, comprising one or more compounds selected from the group of TiN compounds.

[0110] <7> A heat shielding film according to any one of <1> to <6>, wherein the haze is 0.01% or more and 6.0% or less.

[0111] <8> A heat-shielding film according to any of <1> to <7>, wherein the visible light transmittance is 20% or more and 90% or less.

[0112] <9> A heat-shielding film according to any of <1> to <8>, having a solar transmittance of 60% or less.

[0113] <10> The film formation process includes a first layer formation step and a second layer formation step, wherein in the first layer formation step, a film of the general formula WO is formed on a glass substrate. ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂA method for manufacturing a heat shielding film, comprising: forming a first layer containing one or more selected from silicon oxynitride and aluminum oxide; and in the second layer formation step, forming a second layer containing tungsten bronze on the first layer.

[0114] <11> The method for manufacturing a heat shielding film according to <10>, wherein in the film formation step, the first layer and the second 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).

[0115] <12> A method for manufacturing a heat-shielding film according to <10> or <11>, further comprising a heat treatment step of heat-treating the layer formed in the film formation step.

[0116] <13> The method for manufacturing a heat shielding film according to <12>, wherein the heat treatment step is performed in an atmosphere selected from a vacuum atmosphere, an inert gas atmosphere, or a reducing gas atmosphere, at a heat treatment temperature of 300°C or more and 1000°C or less.

[0117] This application claims priority based on Japanese Patent Application No. 2024-184469, filed with the Japan Patent Office on 18 October 2024, and the entire contents of Japanese Patent Application No. 2024-184469 are incorporated herein by reference.

[0118] 10 Heat-shielding film 20 Heat-shielding film 30 Heat-shielding film 11 Glass substrate 12 First layer 121 First film 122 Second film T12 Average film thickness 13 Second layer T13 Average film thickness 14 Protective layer 40 Flowchart S1 First layer deposition process S2 Second layer deposition process S3 Heat treatment process

Claims

1. It comprises a glass substrate, a first layer, and a second layer, wherein the first layer is of general formula WO ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂ A heat shielding film comprising one or more selected from silicon oxynitride and aluminum oxide, wherein the second layer comprises tungsten bronze, and the first layer and the second layer are arranged in that order 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, and the average thickness of the second layer is 5 nm or more and 1200 nm or less.

3. The heat shielding film according to claim 1 or claim 2, wherein the first layer comprises tungsten oxide, and at least a portion of the tungsten oxide is crystallized.

4. The first layer contains tungsten oxide, and the heat shielding film, in the X-ray diffraction pattern, has a tungsten oxide phase and M ｘ１ WO ｚ１ A heat shielding film according to any one of claims 1 to 3, wherein a phase (where element M is one or more elements selected from alkali metals and alkaline earth metals, and x1 satisfies 0.01 ≤ x1 < 1) and a tungsten bronze phase are confirmed.

5. The heat shielding film according to any one of claims 1 to 4, further comprising a protective layer laminated on the second layer.

6. The protective layer is 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 , and contains one or more selected from the group of compounds of TiN. The heat ray shielding film according to claim 5.

7. A heat shielding film according to any one of claims 1 to 6, wherein the haze is 0.01% or more and 6.0% or less.

8. A heat shielding film according to any one of claims 1 to 7, wherein the visible light transmittance is 20% or more and 90% or less.

9. A heat-shielding film according to any one of claims 1 to 8, wherein the solar radiation transmittance is 60% or less.

10. The film formation process includes a first layer formation step and a second layer formation step, wherein in the first layer formation step, a film of the general formula WO is formed on a glass substrate. ３－ｘ Tungsten oxide represented by (0 ≤ x ≤ 0.28), general formula SiO ａ N ｂ A method for manufacturing a heat shielding film, comprising: forming a first layer containing one or more selected from silicon oxynitride and aluminum oxide; and in the second layer formation step, forming a second layer containing tungsten bronze on the first layer.

11. The method for manufacturing a heat shielding film according to claim 10, wherein in the film formation step, the first layer and the second 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).

12. A method for manufacturing a heat shielding film according to claim 10 or claim 11, further comprising a heat treatment step of heat treating the layer formed in the film formation step.

13. The method for manufacturing a heat shielding film according to claim 12, wherein the heat treatment step is performed in an atmosphere selected from a vacuum atmosphere, an inert gas atmosphere, or a reducing gas atmosphere, at a heat treatment temperature of 300°C or more and 1000°C or less.

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