JP5516438B2 - Thermochromic body and method for producing the same - Google Patents

Description

  The present invention relates to a thermochromic body and a method for producing the same, and more particularly to a thermochromic body having a metal underlayer and a method for producing the same. The thermochromic body of the present invention can obtain transmitted light that is more natural than before, and can be applied to, for example, heat-shielding glass.

  Vanadium dioxide is known as a material exhibiting a thermochromic phenomenon. The thermochromic phenomenon refers to a phenomenon in which optical properties change reversibly due to temperature changes. As a thermochromic phenomenon, vanadium dioxide significantly increases the light reflectance in the infrared region as it undergoes a phase transition from a monoclinic system to a tetragonal system rutile structure at about 68 ° C.

  Thus, paying attention to the property that the optical properties of vanadium dioxide change near room temperature, attempts have been made to use vanadium dioxide as a heat ray shielding material. The phase transition of vanadium dioxide is a reversible semiconductor-metal transition. By adding a small amount of tungsten described in Patent Document 1 or molybdenum described in Patent Document 2, the phase transition temperature is set to a temperature near or below room temperature. It can be reduced to temperature.

  In recent years, with increasing environmental awareness, effective use of natural energy has been actively promoted aiming at a low-carbon society. For example, in buildings, heat inflow occurs in summer and heat outflow in winter through openings such as window glass, which contributes to an increase in energy used for air conditioning.

  One way to solve these problems is to prevent wasteful heat from flowing in and out by coating the window glass with a vanadium dioxide-based material that has been adjusted to produce a thermochromic phenomenon near room temperature. As a result, it has been studied to realize energy saving of air conditioning.

  Formation of a good quality vanadium dioxide thin film having a monoclinic crystal structure is generally regarded as a highly difficult technique. For example, as described in Patent Document 1 and Patent Document 2, in order to form a vanadium dioxide-based thin film by a reactive sputtering method using a vanadium metal or vanadium alloy target, the oxygen ratio in the sputtering atmosphere is extremely high. It is necessary to control to a limited range.

  As a method for solving such a problem, for example, Patent Document 3 discloses a method for manufacturing a thermochromic body in which a transition metal base film is formed, thereby forming a vanadium dioxide film in a wide range of oxygen gas flow ratios. Has been proposed. In this method of manufacturing a thermochromic body, the range of the oxygen gas flow rate ratio in the sputtering atmosphere can be expanded by the base film of the transition metal. However, there is a problem in that the visible light transmittance of the manufactured thermochromic body is lowered because large coloring is caused by the base film of the transition metal.

The vanadium dioxide-based thin film exhibits light absorption in the visible light region. For this reason, the vanadium dioxide-based thin film is required to have excellent crystallinity so that the thermochromic characteristics can be exhibited with a thin film thickness as much as possible. However, when a vanadium dioxide-based thin film is directly formed on a glass substrate, a film mainly composed of a VO ₂ phase cannot be obtained unless the film thickness is increased to a required constant value or more.

Non-Patent Document 1 discloses that when a film is formed by reactive RF magnetron sputtering using a V ₂ O ₃ oxide target at a substrate temperature of 400 ° C., the V ₄ O ₉ phase is mainly used at a film thickness of about 200 nm. It is described that a VO ₂ phase becomes the main component when the film thickness exceeds 500 nm. Non-Patent Document 1 discloses that when a film is formed by reactive RF magnetron sputtering in an Ar-5% H ₂ atmosphere using a V ₂ O ₅ oxide target, the film is amorphous at a film thickness of 100 nm or less. It is described that a VO ₂ phase film can be obtained when the film thickness exceeds 400 nm. Actually, in order to reduce light absorption in the visible light region, it is necessary to reduce the film thickness to 100 nm or less. Therefore, practical application of direct film formation on a glass substrate is difficult at present.

In response to such a problem, for example, in Non-Patent Document 2, by forming ZnO of 30 nm or less as a base film on a glass substrate, a film thickness of 100 nm or less is obtained by a process similar to the method described in Non-Patent Document 1. However, it is described that a VO ₂ phase film can be formed. The ZnO base film used in the method described in Non-Patent Document 2 is superior in that it absorbs less visible light than the transition metal base film used in the method described in Patent Document 3. .

Thus, by the method using ZnO as a base film, a VO ₂ phase film with good crystallinity can be formed even with a thin film having a thickness of 100 nm or less. However, in this case, it becomes a two-layer laminated film in which a ZnO base film and a vanadium oxide thin film are sequentially formed on the substrate, and the vanadium oxide thin film becomes the outermost surface layer. As described in Non-Patent Document 3, since the vanadium oxide thin film made of VO ₂ phase has a high refractive index, there is a problem that if it is used as it is for the outermost surface layer, the reflectance with respect to visible light becomes high. .

As a method for solving this problem, the method described in Non-Patent Document 4 is a two-layer laminated film in which an SiO ₂ layer is used as an outermost surface layer and a VO ₂ layer is provided thereunder for the purpose of preventing reflection on the outermost surface. As a result, the transparency of the visible light wavelength region is improved while maintaining the thermochromic performance in the infrared wavelength region. However, transparency is not realized in the entire visible light wavelength range of 400 to 800 nm, and blue light with a wavelength of 400 to 500 nm on the short wavelength side is hardly transmitted. For this reason, the permeation | transmission color of a film | membrane is tinged with yellowishness, and when the practical use by thermochromic glass etc. is considered, the subject was left about visibility.

From the above points, a three-layer laminated film in which ZnO is used as a base film, a VO ₂ layer is formed on this base film, and an SiO ₂ layer is further formed on the VO ₂ layer as the outermost surface layer is effective. Is inferred. However, there is no example of actually forming a three-layer laminated film, and one of the remaining problems of Non-Patent Document 4 is that the blue light having a wavelength of 400 to 500 nm on the short wavelength side hardly transmits. As for the three-layer laminated film, no investigation has been made.

JP-A-7-331430 JP-A-8-3546 JP 2000-137251 A

Jpn. J. et al. Appl. Phys. Vol. 39 (2000) pp. 6016-6024 Jpn. J. et al. Appl. Phys. Vol. 42 (2003) p. 6523-6651 Jpn. J. et al. Appl. Phys. Vol. 43 (2004) p. 186-187 Thin Solid Films Vol. 365 (2000) pp. 5-6

  The present invention relates to a thermochromic body exhibiting high transmittance in the visible light region, particularly on the short wavelength side of a wavelength of 400 to 500 nm, and its production by appropriately controlling the film thickness of each layer of the three-layer laminated film having a thermochromic function. It aims to provide a method.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a zinc oxide thin film as a base film, a vanadium dioxide thin film composed of a VO ₂ phase having good crystallinity, and an outermost layer as In a thermochromic body provided with a three-layer laminated film in which silicon oxide thin films are sequentially laminated, by controlling the film thickness of each layer as appropriate, it is high in the visible light region, particularly on the short wavelength side of a wavelength of 400 to 500 nm. The present inventors have found that the transmittance can be realized, and have completed the present invention.

That is, the first present invention is formed on a zinc oxide thin film as a base film, a vanadium dioxide thin film formed on a zinc oxide thin film, and a vanadium dioxide thin film formed on a substrate. and a silicon oxide thin film, the wavelength lambda ₀ is 200 to 400 nm, the optical thickness of the zinc oxide based thin film is lambda _0/4, the optical thickness of the vanadium dioxide film is in lambda _0/2 the optical thickness of the silicon oxide thin film is a thermochromic material which is a λ _0/4.

According to a second aspect of the present invention, in the first aspect of the present invention, the zinc oxide thin film is selected from a thin film made of zinc oxide, or an element group consisting of zinc, aluminum, gallium, boron, and indium. It is a thermochromic body characterized by being a thin film to which one or more elements are added.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the vanadium dioxide thin film is a thin film made of vanadium dioxide, or a metal element made of vanadium dioxide, tungsten, molybdenum, tantalum, and niobium. The thermochromic body is a thin film formed by adding one or more metal elements selected from the group.

In a fourth aspect of the present invention, in the first or second aspect of the present invention, the vanadium dioxide thin film is a thin film formed by adding tungsten to vanadium dioxide, and the content of tungsten in the vanadium dioxide thin film is W / A thermochromic body characterized in that the atomic ratio represented by (V + W) is 0.001 to 0.1.

According to a fifth aspect of the present invention, in the first or second aspect of the present invention, the vanadium dioxide thin film is a thin film formed by adding molybdenum to vanadium dioxide, and the content of molybdenum in the vanadium dioxide thin film is Mo / The thermochromic body is characterized in that the atomic ratio represented by (V + Mo) is 0.001 to 0.1.

The sixth aspect of the present invention relates to a zinc oxide thin film formed on a substrate as a base film, a vanadium dioxide thin film formed on the zinc oxide thin film, and a silicon oxide formed on the vanadium dioxide thin film. and a system thin film, the wavelength lambda ₀ is 200 to 400 nm, lambda ₁ is the larger 700nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _1/4, vanadium dioxide type the optical thickness of the thin film is λ _0/2, the optical thickness of the silicon oxide thin film is a thermochromic material which is a λ _0/4.

According to a seventh aspect of the present invention, there is provided a zinc oxide thin film as a base film formed on a substrate, a vanadium dioxide thin film formed on the zinc oxide thin film, and a silicon oxide formed on the vanadium dioxide thin film. and a system thin film, the wavelength lambda ₀ is 200 to 400 nm, lambda ₃ is a greatly 700nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _0/4, vanadium dioxide type the optical thickness of the thin film is λ _0/2, the optical thickness of the silicon oxide thin film is a thermochromic material which is a lambda _3/4.

According to an eighth aspect of the present invention, there is provided a zinc oxide thin film as a base film formed on a substrate, a vanadium dioxide thin film formed on the zinc oxide thin film, and a silicon oxide formed on the vanadium dioxide thin film. and a system thin film, the wavelength lambda ₀ is 200 to 400 nm, lambda _1, lambda ₃ are both a large 600nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _1/4 , and the optical thickness of the vanadium dioxide film is lambda _0/2, the optical thickness of the silicon oxide thin film is a thermochromic material which is a lambda _3/4.

The present invention of a 9 is a solar control glass comprising a thermochromic material of any one of the present invention the first to eighth.

The present invention of a 10 forms a zinc oxide-based thin film as a base film on a substrate, a vanadium dioxide thin film formed on the zinc oxide-based thin film, a silicon oxide based film on a vanadium dioxide thin film, 200 the wavelength lambda ₀ is to 400 nm, the optical thickness of the zinc oxide based thin film and λ _0/4, the optical thickness of the vanadium dioxide thin film and λ _0/2, the optical thickness of the silicon oxide based thin film lambda a method for producing thermochromic material, characterized in that the _0/4.

According to the present invention, in a thermochromic body provided with a three-layer laminated film, by controlling the film thickness of each layer of the three-layer laminated film as appropriate, a high transmittance in the visible light region, particularly on the short wavelength side of a wavelength of 400 to 500 nm. It is possible to obtain Specifically, by setting the wavelength λ ₀ to 200 to 400 nm, high transmittance is exhibited in the visible light region, particularly in the short wavelength side of the wavelength 400 to 500 nm. Further, according to the present invention, by increasing the zinc oxide based thin film is a first film layer and / or a silicon oxide based thin film is a third thin film layer from the optical film thickness lambda _0/4, further high transmittance Indicates the rate.

It is typical sectional drawing of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability ((lambda) 0 = 300nm) in room temperature and 80 degreeC of a thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the reflectance in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the reflectance in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the reflectance in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the reflectance in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the transmittance | permeability in the room temperature of the thermochromic body provided with the 3 layer laminated film. It is a figure which shows the reflectance in the room temperature of the thermochromic body provided with the 3 layer laminated film.

Hereinafter, embodiments of the thermochromic body of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail in the following order with reference to the drawings.
1. Thermochromic body2. 2. First modification of thermochromic body 2. Second modification of thermochromic body 4. Third modification of thermochromic body 5. Method for producing thermochromic body Application example of thermochromic body 7. Example

(1. Thermochromic body)
The thermochromic body in the present embodiment will be described. As shown in FIG. 1, in the thermochromic body 1 according to the present embodiment, a zinc oxide-based thin film 11 is formed on a base 20 as a first thin film layer that is a base film. A vanadium dioxide thin film 12 is formed as a second thin film layer on the zinc oxide thin film 11, and a silicon oxide thin film 13 is formed as a third thin film layer on the vanadium dioxide thin film 12. That is, the thermochromic body 1 includes a three-layer laminated film 10 including a zinc oxide thin film 11, a vanadium dioxide thin film 12, and a silicon oxide thin film 13 on a base 20.

The thermochromic body 1, the wavelength lambda ₀ is 400nm or less, the optical thickness of the zinc oxide based thin film is lambda _0/4, the optical thickness of the vanadium dioxide film is lambda _0/2, the optical thickness of the silicon oxide based thin film is λ _0/4. In the thermochromic body 1, since the wavelength λ ₀ and the optical film thickness of each layer have such a relative relationship, a high transmittance is obtained in the visible light region, particularly in the short wavelength side of the wavelength of 400 to 500 nm, at the wavelength λ ₀ . It is possible. The wavelength λ ₀ is preferably 200 to 400 nm.

  The zinc oxide-based thin film 11 as the first thin film layer, which is the base film, is a thin film made of zinc oxide or 1 selected from the group of elements consisting of zinc, aluminum, gallium, boron, and indium. It is a thin film formed by adding more than seed elements. As a result, the vanadium dioxide thin film 12 as the second thin film layer formed on the zinc oxide thin film 11 as the first thin film layer can be formed with low crystallinity at a low substrate temperature. That is, even if the vanadium dioxide thin film 12 is an ultrathin thin film having a thickness of 100 nm or less, high crystallinity can be exhibited.

  When the zinc oxide-based thin film 11 is a thin film formed by adding one or more elements selected from the group consisting of aluminum, gallium, boron, and indium to zinc oxide, the content of each element Is preferably 0.10 or less in terms of the atomic ratio represented by (Al + Ga + B + In) / (Zn + Al + Ga + B + In). When this atomic ratio exceeds 0.10, the crystallinity of the zinc oxide thin film is low, and as a result, the vanadium dioxide thin film 12 cannot be formed with good crystallinity.

  Even when the oxide target is used as a starting material and the zinc oxide thin film 11 is formed by direct current sputtering, the atomic ratio represented by (Al + Ga + B + In) / (Zn + Al + Ga + B + In) in the oxide target is 0.10. The following is preferable. If this atomic ratio exceeds 0.10, arcing is likely to occur, making DC sputtering difficult.

In addition, the zinc oxide-based thin film 11 has high transparency and low visible light absorption. Therefore, the thickness of the zinc oxide-based thin film 11 is not particularly limited, but is preferably an integer multiple of λ- ₀ / 4 in terms of the optical thickness.

  The vanadium dioxide thin film 12 as the second thin film layer is a thin film made of vanadium dioxide, or one or more metal elements selected from the group of metal elements made of vanadium dioxide, tungsten, molybdenum, tantalum, and niobium. It is a thin film formed by adding a metal element.

The vanadium dioxide thin film 12 as the second thin film layer is a crystal film made of a VO ₂ phase represented by a monoclinic space group P2 ₁ / c. When the VO ₂ phase exceeds the transition point, it transforms into a tetragonal VO ₂ phase represented by the space group P4 ₂ / mnm, thereby exhibiting thermochromic characteristics.

  In particular, in order to control the transition point, tungsten or molybdenum is preferably contained. The content of tungsten is preferably 0.001 to 0.1, more preferably 0.01 to 0.02, in terms of the atomic ratio represented by W / (V + W). The molybdenum content is preferably 0.001 to 0.1, more preferably 0.02 to 0.045, in terms of the atomic ratio represented by Mo / (V + Mo). Note that the content of inevitable impurities is not necessarily specified by such an atomic ratio.

The vanadium dioxide-based thin film 12 is a monoclinic system represented by the space group P2 ₁ / c described in JCPDS card 44-0252 in a temperature range below the transition point from the viewpoint that excellent thermochromic characteristics can be obtained. The crystal structure of When the vanadium dioxide thin film 12 has a monoclinic crystal structure, when the metal element group is not added, a semiconductor-metal phase transition occurs at a transition temperature of 68 ° C., which is described in JCPDS Card 44-0253. Transition to the tetragonal rutile crystal structure represented by the space group P4 ₂ / mnm. When an appropriate amount of the metal element group is contained, the transition temperature at 68 ° C. can be controlled to be near room temperature.

The vanadium dioxide thin film 12 has a large light absorption. Therefore, the thickness of the vanadium dioxide-based thin film 12, thinner is preferable, it is preferably an integer multiple of lambda _0/2 in the optical film thickness. In order for the vanadium dioxide thin film 12 to effectively function as a thermochromic film, the wavelength λ ₀ is set to 400 nm or less. More preferably, it is 200 to 400 nm. By setting the wavelength λ ₀ to 200 to 400 nm, it is possible to control so that the maximum (maximum) transmittance and the minimum (minimum) reflectance are favorably obtained in the visible light wavelength range.

  Since the vanadium dioxide thin film 12 is made of vanadium dioxide, the refractive index is high (see Non-Patent Document 3). On the other hand, the silicon oxide thin film 13 has a low refractive index. For this reason, the silicon oxide thin film 13 is formed on the outermost surface of the thermochromic body for the purpose of reducing light reflection on the surface due to the high refractive index of the vanadium dioxide thin film 12. By forming the silicon oxide thin film 13 on the vanadium dioxide thin film 12, the reflectance of light on the outermost surface of the thermochromic body 1 can be effectively reduced.

The silicon oxide thin film 13 is preferably a silicon dioxide (SiO ₂ ) thin film, but is not limited thereto, and may be, for example, a SiO _{2 -x} thin film having oxygen vacancies that do not cause significant light absorption. The material of the silicon oxide thin film may be crystalline or amorphous.

The silicon oxide thin film 13 has high transparency and low absorption of visible light. Thus, although the film thickness of the silicon oxide film 13 is not particularly limited, it is preferably basically an integral multiple of lambda _0/4 in optical thickness.

  By providing such a three-layer laminated film 10, the thermochromic body 1 can obtain a high transmittance in the visible light region, particularly in the short wavelength side with a wavelength of 400 to 500 nm.

  The thermochromic body 1 is configured for the purpose of improving the transmittance in the visible light region. Specifically, the thermochromic body 1 preferably has a maximum transmittance of 50% or more and a transmittance at a wavelength of 500 nm of 40% or more.

  Generally, as a method for improving the transmittance in the visible light region, the reflectance in the visible light region is lowered. The antireflection structure is applied to a multilayer film such as a three-layer laminated film in which each layer is composed of a film having low light absorption and high transparency. In this case, when the central wavelength of the antireflection effect is λ, the optical film thickness of the low refractive index layer that is the first thin film layer from the substrate side is λ / 4, and the optical thickness of the high refractive index layer that is the second thin film layer. The film thickness is designed to be λ / 2, and the optical film thickness of the low refractive index layer or intermediate refractive index layer to be the third thin film layer is designed to be λ / 4. In this case, since the wavelengths indicating the maximum transmittance in the visible light region are substantially the same, in order to improve the transmittance in the visible light region, the wavelength 550 nm having high visibility may be set as the center wavelength λ.

The thermochromic body 1 has a film structure similar to such a normal antireflection structure. However, since the thermochromic body 1 includes the vanadium dioxide thin film 12 that absorbs relatively large visible light as the second thin film layer, the center wavelength of the antireflection effect coincides with the wavelength indicating the maximum transmittance in the visible light region. do not do. Therefore, the wavelength λ ₀ that provides a good transmittance is determined by examining the change in the transmittance of the thermochromic body 1 in the visible light region while changing the wavelength λ. In order to improve the transmittance of the blue light region, which is the short wavelength side of the visible light region having a wavelength of 400 to 500 nm, the wavelength λ ₀ is set to 400 nm or less. For example, the wavelength λ ₀ is 200 to 400 nm.

When the wavelength λ ₀ exceeds 400 nm, for example, when the wavelength λ ₀ is 500 nm, the maximum transmittance in the visible light region at the wavelength 660 nm shows about 55%, but as in the technique described in Non-Patent Document 4, Absorption of light on the short wavelength side of the visible light region having a wavelength of 400 to 500 nm is increased, and specifically, the transmittance at a wavelength of 500 nm is about 34%.

  Hereinafter, modifications of the thermochromic body in the present embodiment will be described. The modification of the thermochromic body described below has basically the same configuration as the thermochromic body 1. For this reason, the same code | symbol is attached | subjected about the structure same as the thermochromic body 1, and description is abbreviate | omitted.

(2. First modification of thermochromic body)
A thermochromic body 1A, which is a first modification of the thermochromic body in the present embodiment, is a zinc oxide-based thin film 11A as a first thin film layer that is a base film, and a first formed on the zinc oxide thin film 11A. A three-layer laminated film 10A comprising a vanadium dioxide thin film 12 as the second thin film layer and a silicon oxide thin film 13 as the third thin film layer formed on the vanadium dioxide thin film 12 is formed on the substrate 20. It becomes.

In the three-layer laminated film 10A, as described above, the wavelength λ ₀ is set to 400 nm or less in order to improve the transmittance on the short wavelength side in the visible light wavelength region. For example, a high transmittance can be obtained by setting the wavelength λ ₀ to 200 to 400 nm.

In thermochromic body 1A, vanadium dioxide-based thin film 12 an optical film thickness of lambda _0/2, that the optical thickness comprises a silicon oxide film 13 is lambda _0/4 is the same as the thermochromic material 1 . However, thermochromic body 1A is, the wavelength lambda _0, the lambda ₁ to a value larger than lambda _0, instead of the zinc oxide based thin film 11 described above, the zinc oxide based thin film 11A an optical film thickness of lambda _1/4 Is provided. λ ₁ is larger than λ ₀ and 700 nm or less.

Thus, thermochromic body 1A at a wavelength lambda ₀ ≦ 400 nm, vanadium dioxide-based thin film 12, while fixing the optical film thickness of the silicon oxide film 13, respectively lambda _0/2, the lambda _0/4, zinc oxide by the optical film thickness of the system thin film 11A and the thick lambda _1/4 than λ _0/4, it becomes possible to increase the transmittance of visible light.

The visible light transmittance can be further increased by increasing the optical film thickness. However, in order to further increase the visible light transmittance in the three-layer laminated film including the vanadium dioxide thin film 12 having a large visible light absorption, the antireflection effect is enhanced unlike the three-layer laminated film including only the transparent thin film. Too much is rather undesirable. For this reason, as described above, λ ₁ is set to 700 nm or less.

(3. Second modification of thermochromic body)
A thermochromic body 1B, which is a second modification of the thermochromic body in the present embodiment, is formed on the zinc oxide thin film 11 as a base film formed on the substrate 20 and the zinc oxide thin film 11. A three-layer laminated film 10B including a vanadium dioxide thin film 12 as a second thin film layer and a silicon oxide thin film 13B as a third thin film layer formed on the vanadium dioxide thin film 12 is provided.

In the three-layer laminated film 10B, as described above, the wavelength λ ₀ is set to 400 nm or less in order to improve the transmittance on the short wavelength side in the visible light wavelength region. The wavelength λ ₀ is, for example, 200 to 400 nm.

In thermochromic body 1B, zinc oxide based thin film 11 an optical film thickness of λ _0/4, the point that the optical film thickness is provided with a vanadium dioxide-based thin film 12 is λ _0/2, is the same as the thermochromic material 1 . However, thermochromic body 1B is the wavelength lambda _0, the lambda ₃ and larger than lambda _0, instead of silicon oxide thin film 13 described above, a silicon oxide based thin film 13B an optical film thickness of lambda _3/4 Is provided. Also in the thermochromic body 1B, as described above, λ ₃ is set to 700 nm or less for the purpose of preventing the antireflection effect from being excessively increased.

Thus, thermochromic member 1B at a wavelength lambda ₀ ≦ 400 nm, zinc oxide-based thin film 11, λ _0/4, respectively an optical film thickness of the vanadium dioxide-based thin film 12, and fixed to the lambda _0/2, the third by the optical film thickness of the thin film layer 13A and the thicker lambda _3/4 than λ _0/4, it becomes possible to increase the transmittance of visible light.

(4. Third modification of thermochromic body)
A thermochromic body 1C, which is a third modification of the thermochromic body in the present embodiment, includes a zinc oxide-based thin film 11A as a first thin film layer that is a base film formed on a base 20, and a zinc oxide-based film. A three-layer laminated film comprising a vanadium dioxide thin film 12 as a second thin film layer formed on the thin film 11A and a silicon oxide thin film 13B as a third thin film layer formed on the vanadium dioxide thin film 12 10C.

In the three-layer laminated film 10C, as described above, the wavelength λ ₀ is set to 400 nm or less in order to improve the transmittance on the short wavelength side in the visible light wavelength region. The wavelength λ ₀ is, for example, 200 to 400 nm.

In thermochromic member 1C, the point having the second thin film layer 12 an optical film thickness of lambda _0/2, is the same as the thermochromic material 1. However, in the thermochromic body 1C, λ ₁ and λ ₃ are both larger than λ ₀ with respect to the wavelength λ ₀ , and the optical film is replaced with the first thin film layer 11 and the third thin film layer 13 described above. thickness zinc-based thin film 11A and the optical film thickness oxide is lambda _1/4 comprises a silicon oxide film 13B is a lambda _3/4. Also in this thermochromic body 1C, both λ ₁ and λ ₃ are set to 600 nm or less for the purpose of preventing the above-described antireflection effect from being excessively increased.

Thus, thermochromic member 1C at a wavelength lambda ₀ ≦ 400 nm, and fixing the optical thickness of the vanadium dioxide-based thin film 12, respectively lambda _0/2, a zinc-based thin film 11A oxide, the optical film of the silicon oxide film 13B the thickness both lambda _{0 /} thicker than 4 λ _1/4, by a lambda _3/4, it becomes possible to increase the transmittance of visible light.

  As described above, the film thickness control for fixing the film thickness of the second thin film layer and increasing the film thickness of the first thin film layer and / or the third thin film layer is the first thin film layer and / or Or it is synonymous with fixing the film thickness of a 3rd thin film layer, and making the film thickness of a 2nd thin film layer thin.

(5. Method for producing thermochromic body)
In the thermochromic 1, a zinc oxide thin film 11 is formed as a base film on a base 20, a vanadium dioxide thin film 12 is formed on the zinc oxide thin film 11, and a silicon oxide thin film 13 is formed on the vanadium dioxide thin film 12. It is manufactured by forming.

  The thermochromic body 1 is formed on the substrate 20 by a conventionally known film formation method, that is, a physical film formation method such as sputtering, ion plating, or PLD described in Patent Document 1, or Patent Document 4 is manufactured by sequentially forming thin films by a chemical film forming method such as a chemical vapor deposition (CVD) method, a spray method, or a metal organic deposition (MOD) method described in 4.

  As a manufacturing method of the thermochromic body 1, a sputtering method is particularly preferable. Specific examples include direct current sputtering, direct current pulse sputtering, and high frequency sputtering. Among these methods, as described in Patent Document 1, a high-frequency sputtering method is generally applied to the formation of a vanadium dioxide thin film. Also in this embodiment, when a vanadium oxide sintered body target is used, a high frequency sputtering method is particularly preferable.

  When a vanadium metal target is used, a direct current pulse sputtering method is also useful. The DC pulse sputtering method employs a frequency of several hundred kHz lower than the general frequency of 13.56 MHz in the high frequency sputtering method, or changes the waveform of the applied current and applied voltage (for example, changes to a rectangular shape). It is included in the DC sputtering method in a broad sense.

  In the DC pulse sputtering method, the negative voltage applied to the target is periodically stopped, and a low positive voltage is applied between them to neutralize positive charging with electrons, thereby forming a film while suppressing arcing. Is possible. The direct current pulse sputtering method does not need to control the impedance matching circuit unlike the high frequency sputtering method, and has an advantage that the film forming speed is faster than the high frequency sputtering method.

  Further, the direct-current pulse sputtering method can form a vanadium dioxide-based thin film by precisely controlling the optimal oxygen amount in combination with PEM (Plasma Emission Monitor) or the like. In addition, even if it is direct current | flow sputtering method or direct current | flow pulse sputtering method, in order to implement | achieve high-speed film-forming, all have a conductive target required.

  When the thermochromic body 1 is formed by various sputtering methods, it is preferable to use a mixed gas composed of an inert gas and oxygen, particularly argon and oxygen, as a sputtering gas. Further, it is preferable to perform sputtering in a chamber of the sputtering apparatus at a pressure of 0.1 to 5 Pa, particularly 0.2 to 0.8 Pa.

For example, after evacuating to 2 × 10 ⁻⁴ Pa or less, a mixed gas composed of argon and oxygen is introduced, the gas pressure is set to 0.2 to 0.5 Pa, and the DC power with respect to the area of the target, that is, the DC power density is 1. Pre-sputtering can be performed by generating a plasma by applying power so as to be in a range of about ˜3 W / cm ² . After pre-sputtering is performed for 5 to 30 minutes to stabilize the discharge state, it is preferable to perform sputtering film formation after correcting the substrate position if necessary.

  By forming the film by heating the substrate to a predetermined temperature, a crystal film in which each layer has a desired structure can be obtained. The substrate temperature is preferably 200 ° C. or higher and 500 ° C. or lower. Alternatively, an amorphous film may be formed at a low temperature near room temperature, and then the crystal film may be formed by heat treatment in an appropriate atmosphere such as non-oxidizing property.

  The above-described thermochromic bodies 1A, 1B, and 1C can also be manufactured by the same method as the manufacturing method of the thermochromic body 1 described here.

(6. Application example of thermochromic body)
The thermochromic body 1 can be suitably applied to, for example, a heat ray shielding glass or a heat ray shielding film. In the heat ray shielding glass or the heat ray shielding film, for example, glass or film is used as the base 10, a base film 11 made of a zinc oxide thin film is formed on the base 10, and a vanadium dioxide thin film 12 is formed on the base film 11. It can be obtained by forming the silicon oxide thin film 13 on the vanadium dioxide thin film 12. At this time, the heat ray shielding glass and the heat ray shielding film are sequentially formed on the substrate 10 by laminating thin films in which the optical film thickness of each thin film layer of the base film 11, the vanadium dioxide thin film 12, and the silicon oxide thin film 13 is controlled. By doing, it can be set as the heat ray shielding film or heat ray shielding glass which can obtain a high transmittance | permeability in visible light region, especially the short wavelength side of wavelength 400-500 nm.

(7. Example)
Hereinafter, the present invention will be described in more detail with reference to examples of the present invention, but the present invention is not limited to these examples.

  The composition of the thin film of each thin film layer of the thermochromic body produced in the following examples and comparative examples was examined by ICP emission spectroscopy. The film thickness of each thin film layer was measured with a surface roughness meter (Alpha-Step IQ manufactured by Tencor). The film formation rate was calculated from the film thickness and the film formation time.

  The formation phase of the film was identified by 2θ / θ measurement using an X-ray diffractometer (Philips X′Pert PRO MPD).

  As the optical characteristics of the manufactured thermochromic body, transmittance and reflectance at room temperature and transmittance at 80 ° C. are measured using a spectrophotometer (V-570 manufactured by JASCO Corporation and U-4100 manufactured by Hitachi High-Technologies Corporation). The maximum transmittance and the minimum reflectance at a wavelength of 300 to 1000 nm at room temperature were calculated from these measurement data.

Example 1
A base film made of a zinc oxide thin film is formed as a first thin film layer on the substrate, a vanadium dioxide thin film is formed as a second thin film layer on the base film, and a third film is formed on the vanadium dioxide thin film. A silicon oxide thin film was formed as the thin film layer. Thus, a thermochromic body formed by forming a three-layer laminated film on the substrate was manufactured. In thermochromic body manufactured, first the optical thickness of the thin film layer lambda _0/4, the optical film thickness lambda _0/2 of the second thin film layer, the optical thickness of the third thin film layer lambda ₀ / It was set to 4. In Example 1, the wavelength λ ₀ was set to 300 nm.

Specifically, a magnesium oxide oxide sintered body and a vanadium dioxide oxide are applied to a nonmagnetic target cathode of a magnetron sputtering apparatus (SPF-530H, manufactured by Anelva) equipped with a DC power source and a high-frequency power source that do not have an arcing suppression function. Film formation was performed by attaching three types of sputtering targets of a sintered body and metallic silicon (silicon). As the substrate, a Corning 7059 glass substrate having a thickness of 1.1 mm was used. The inside of the chamber of the sputtering apparatus was evacuated to a vacuum of 1 × 10 ⁻⁴ Pa or less, and it was confirmed that the substrate temperature reached 400 ° C.

First, a zinc oxide thin film as a base film was formed as a first thin film layer on a glass substrate as a substrate. In forming the zinc oxide thin film, argon gas was introduced and the total gas pressure was adjusted to 0.3 Pa. The target-substrate distance was 49 mm. High-frequency plasma was generated by applying DC power of 200 W, and film formation was performed by DC sputtering. After 10 minutes of pre-sputtering, immediately above the sputtering target, i.e. the substrate is placed in a stationary opposed position, and carried out sputtering at a substrate temperature of 400 ° C., to form a zinc oxide thin film having an optical thickness of λ _0/4.

Next, a vanadium dioxide thin film was formed as a second thin film layer on the zinc oxide thin film as the first thin film layer. In forming the vanadium dioxide thin film, a mixed gas of argon and oxygen was introduced so that the oxygen ratio was 0.7%, and the gas pressure was adjusted to 0.5 Pa. The distance between the target and the substrate was 60 mm. A high-frequency plasma was generated by applying a high-frequency power of 200 W, and a film was formed by high-frequency sputtering. After 10 minutes of pre-sputtering, immediately above the sputtering target, i.e. the substrate is placed in a stationary position facing, carried out sputtering at the same substrate temperature as the zinc oxide thin film was formed of vanadium dioxide thin film having an optical thickness of λ _0/2.

Furthermore, a silicon oxide thin film was formed as a third thin film layer on the vanadium dioxide thin film as the second thin film layer. In forming the silicon oxide thin film, a mixed gas of argon and oxygen was introduced so that the oxygen ratio was 2.0%, and the gas pressure was adjusted to 0.5 Pa. The distance between the target and the substrate was 60 mm. A high-frequency plasma was generated by applying a high-frequency power of 200 W, and a film was formed by high-frequency sputtering. After 10 minutes of pre-sputtering, immediately above the sputtering target, i.e. the substrate is placed in a stationary opposed position, and carried out sputtering at the same substrate temperature as the zinc oxide thin film was formed a silicon oxide thin film having an optical thickness of lambda _0/4 .

Through the above steps, a thermochromic body including a three-layer laminated film having a wavelength λ ₀ was manufactured.

The crystallinity of the three-layer laminated film provided in the thermochromic body thus manufactured was examined by X-ray diffraction measurement. As a result, formation of a ZnO phase was confirmed in the first thin film layer, and generation of a VO ₂ phase composed of a monoclinic crystal structure of the space group P2 ₁ / c was confirmed in the second thin film layer. It was. In the 3rd thin film layer, since the diffraction peak was not confirmed, it was judged that it was amorphous.

  In FIG. 2, the transmittance | permeability in the room temperature and 80 degreeC of the thermochromic body of Example 1 is shown, respectively. 3 shows the transmittance profile at room temperature of the thermochromic body of Example 1, and FIG. 4 shows the reflectance profile of the thermochromic body of Example 1 at room temperature. 3 to 5 and 7 to 12 also show profiles of other necessary examples and comparative examples for comparison.

  As shown in FIGS. 2 and 3, the maximum transmittance is 50.8% at a wavelength of 572 nm, and the transmittance at a wavelength of 500 nm is 48.0%, which exceeds 40%. Furthermore, as shown in FIG. 4, it was found that the wavelength exhibiting the minimum reflectance of 6.7% is 388 nm, which is lower than the wavelength exhibiting the maximum transmittance.

Thus, in the thermochromic body of Example 1 which formed the zinc oxide thin film as a base film, it turned out that a high transmittance | permeability is obtained and a reflectance is reduced by setting wavelength (lambda) ₀ to 300 nm.

(Example 2 and Example 3)
A thermochromic body was manufactured in the same manner as in Example 1 except that the wavelength λ ₀ was 400 nm in Example 2 and the wavelength λ ₀ was 200 nm in Example 3.

  In FIG. 3, the transmittance | permeability profile of the thermochromic body of Example 2 and the thermochromic body of Example 3 is shown. FIG. 4 shows the reflectance profiles of the thermochromic body of Example 2 and the thermochromic body of Example 3.

  As shown in FIG. 3, in Example 2, the maximum transmittance is 55.8% at a wavelength of 624 nm, and the transmittance at a wavelength of 500 nm is 48.0%, which exceeds 40%. In Example 3, the maximum transmittance is 54.4% at a wavelength of 800 nm, and the transmittance at a wavelength of 500 nm is 44.6%, which exceeds 40%. Further, as shown in FIG. 4, in Example 2, the wavelength showing the minimum reflectance of 6.7% is 440 nm, and in Example 3, the wavelength showing the minimum reflectance of 5.7% is 266 nm. Unlike the wavelength exhibiting the maximum transmittance, the wavelength was found to be lower.

(Comparative Example 1 and Comparative Example 2)
A thermochromic body was manufactured in the same manner as in Examples 1 to 3 except that the wavelength λ ₀ was 500 nm in Comparative Example 1 and the wavelength λ ₀ was 550 nm in Comparative Example 2.

  FIG. 3 shows transmittance profiles of the thermochromic body of Comparative Example 1 and the thermochromic body of Comparative Example 2. FIG. 4 shows the reflectance profiles of the thermochromic body of Comparative Example 1 and the thermochromic body of Comparative Example 2.

  3, Comparative Example 1 shows a maximum transmittance of 55.2% at a wavelength of 660 nm, and Comparative Example 2 shows a maximum transmittance of 53.7% at a wavelength of 687 nm, while the transmittance at a wavelength of 500 nm is 40%. 33.8% (Comparative Example 1) and 30.1% (Comparative Example 2). In FIG. 4, in Comparative Example 1, the wavelength indicating the minimum reflectance of 2.3% is 572 nm, and in Comparative Example 2, the wavelength indicating the minimum reflectance of 2.2% is 622 nm. Unlike the wavelength showing the maximum transmittance, it was found to be a lower wavelength.

As is apparent from the results shown in FIGS. 3 and 4, in the thermochromic body including the three-layer laminated film, when the wavelength λ ₀ is larger than 300 nm, the transmittance profile shifts to the longer wavelength side. For this reason, when 300 nm <λ ₀ , it was found that the transmittance on the short wavelength side of the visible light region having a wavelength of 400 to 500 nm decreases as the wavelength λ ₀ is increased. Specifically, when the wavelength λ ₀ is 400 nm, the transmittance at a wavelength of 500 nm is higher than 40%, but when the wavelength λ ₀ is 500 nm or more, it is lower than 40%.

From the results of Examples 1 and 2 and Comparative Examples 1 and 2, in order to improve the transmittance on the short wavelength side of the visible light region having a wavelength of 400 to 500 nm, the wavelength λ _{0 of the} thermochromic body having a three-layer laminated structure is set. It was found that it was necessary to make the thickness 400 nm or less.

(Examples 4 to 6)
Except that thicker than the first both lambda _0/4 optical thickness of the silicon oxide thin film of the optical thickness and the third thin film layer of zinc oxide thin film layer, the same treatment as in Example 1 The thermochromic body was manufactured. Specifically, for the optical thickness of the vanadium dioxide thin film of the second thin film layer, the wavelength lambda ₀ is fixed to the lambda _0/2 at 300 nm, the optical thickness of the zinc oxide thin film lambda _1/4, a silicon oxide film the optical thickness λ _3/4, both the wavelength lambda ₁ and lambda ₃ 400 nm (example 4), 500 nm (example 5), 600 nm was set to be (example 6) corresponding optical thickness .

  In FIG. 5, the profile of the transmittance | permeability of the thermochromic body of Examples 4-6 is shown. Moreover, the reflectance profile of the thermochromic body of Examples 4-6 is shown in FIG.

  As shown in FIG. 5, in Example 4, the maximum transmittance is 59.0% at a wavelength of 604 nm, and the transmittance at a wavelength of 500 nm is 52.2%, which exceeds 40%. In Example 5, the maximum transmittance is 64.0% at a wavelength of 632 nm, and the transmittance at a wavelength of 500 nm is 50.4%, which exceeds 40%. Furthermore, in Example 6, the maximum transmittance is 65.6% at a wavelength of 662 nm, and the transmittance at a wavelength of 500 nm is 44.7%, which exceeds 40%.

  As shown in FIG. 6, in Example 4, the wavelength indicating the minimum reflectance of 8.1% is 468 nm, and in Example 5, the wavelength indicating the minimum reflectance of 7.6% is 548 nm. Then, it was found that the wavelength exhibiting the minimum reflectance of 6.2% was 624 nm, and in any case, the wavelength was lower than the wavelength exhibiting the maximum transmittance.

(Comparative Example 3)
Except that thicker than the first optical thickness and the third thin film layer of zinc oxide thin films both lambda _0/4 optical thickness of the silicon oxide thin film is a thin film layer, the same treatment as in Example 1 The thermochromic body was manufactured. Specifically, the optical thickness of the vanadium dioxide thin film of the second thin film layer is fixed wavelength lambda ₀ to 300 nm, the optical thickness of the zinc oxide thin film lambda _1/4 and the optical thickness of the silicon oxide thin film lambda ₃ / 4 was thickened so that the wavelengths λ ₁ and λ ₃ both had an optical film thickness equivalent to 700 nm.

  In FIG. 5, the transmittance | permeability profile of the thermochromic body of the comparative example 3 is shown. FIG. 6 shows the reflectance profile of the thermochromic body of Comparative Example 3.

  As shown in FIG. 5, Comparative Example 3 shows a maximum transmittance of 65.2% at a wavelength of 752 nm. On the other hand, the transmittance at a wavelength of 500 nm is only 38.3%, which is lower than 40%. As shown in FIG. 6, in Comparative Example 3, it was found that the wavelength exhibiting the minimum reflectance of 5.9% was 696 nm, which was lower than the wavelength exhibiting the maximum transmittance.

(Comparative Example 4)
Except that together thinner than the first both lambda _0/4 optical thickness of the silicon oxide film is an optical film thickness, and the third thin film layer of zinc oxide thin film is a thin film layer, as in Example 1 The process was performed and the thermochromic body was manufactured. Specifically, the optical thickness of the vanadium dioxide thin film is a second thin film layer is fixed wavelength lambda ₀ to 300 nm, the optical thickness of the optical film thickness lambda _1/4 and a silicon oxide thin film of zinc oxide thin film lambda _3/4, the wavelength lambda ₁ and lambda ₃ is made thin so as to have an optical thickness of 200nm equivalent.

  In FIG. 5, the transmittance | permeability profile of the thermochromic body of the comparative example 4 is shown. FIG. 6 shows the reflectance profile of the thermochromic body of Comparative Example 4.

  As shown in FIG. 5, in Comparative Example 4, the maximum transmittance is a low value of 44.2% at a wavelength of 656 nm, and the transmittance at a wavelength of 500 nm is only 40.7%, slightly exceeding 40%. It was. As shown in FIG. 6, in Comparative Example 4, it was found that the wavelength showing the minimum reflectance of 4.1% was 256 nm, which was lower than the wavelength showing the maximum transmittance.

Thus, thermochromic material and the first optical film thickness of the optical thickness and the third thin layer of thin layers both thicker than lambda _0/4, from the results of Example 1 and Examples 4-6 Apparently, when the wavelengths λ ₁ and λ ₃ are 300 to 600 nm, the transmittance at the wavelength of 500 nm exceeded 40%. However, as shown in the result of Comparative Example 3, the wavelengths λ ₁ and λ ₃ were 700 nm. In some cases less than 40%.

On the other hand, thermochromic material and the optical thickness of the optical thickness and the third thin film layer of the first thin film layer both thinner than lambda _0/4, as is clear from the results of Comparative Example 4, the wavelength lambda ₁ When λ ₃ is 200 nm, the antireflection effect due to the three-layer laminated film cannot be sufficiently obtained, and the transmittance in the visible light region cannot be sufficiently improved.

From the results of Example 1 and Examples 4 to 6, Comparative Example 3, and Comparative Example 4, the wavelength λ _{0 of the} thermochromic body provided with the three-layer laminated film is fixed, and the first thin film layer and the third thin film layer preferably better to thicker than the optical thickness both the lambda _0/4, the case is further fixed wavelength lambda _0, the optical of the first optical film thickness of the thin layer lambda _1/4 and the third thin film layer the thickness _{λ 3/4, λ 1,} λ 3 is effective in improving the transmittance in the visible light region is thermochromic material having a three-layer laminate film of thickening to be in the range of equivalent 300~600nm I found out.

(Comparative Example 5)
The thermochromic body provided with the two-layer laminated film was manufactured by performing the same treatment as in Example 1 except that the silicon oxide thin film serving as the third thin film layer on the outermost surface was not formed.

  In FIG. 5, the transmittance | permeability profile of the thermochromic body of the comparative example 5 is shown. FIG. 6 shows the reflectance profile of the thermochromic body of Comparative Example 5.

  As shown in FIG. 5, the thermochromic body of Comparative Example 5 has a low maximum transmittance of 42.1% at a wavelength of 790 nm, and the transmittance at a wavelength of 500 nm is only 36.5%, which is less than 40%. It was. In addition, as shown in FIG. 6, it turned out that the comparative example 5 shows very high reflectance of about 40% in the whole visible light region.

From the results of Example 1 and Comparative Example 5 as described above, when the wavelength λ ₀ is λ ₀ ≦ 400 nm, a thermo provided with a three-layer laminated film in which a silicon oxide thin film is formed as the outermost third thin film layer. It can be seen that the chromic body can obtain higher transmittance in the visible light region, particularly in the wavelength of 500 nm, compared to the thermochromic body provided with the two-layer laminated film that does not form the silicon oxide thin film as the third thin film layer. It was.

(Example 7 and Example 8)
Except that the optical film thickness of the zinc oxide thin film of the first thin film layer thicker than lambda _0/4, was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, with respect to the optical film thickness of the vanadium dioxide thin film of the second thin film layer and the silicon oxide thin film of the third thin film layer, the wavelength λ ₀ is fixed at 300 nm, and only the zinc oxide thin film has a wavelength λ ₁ of 500 nm. (example 7), 700 nm and thick so that the (example 8) equivalent optical thickness λ _1/4.

  FIG. 7 shows the transmittance profiles of the thermochromic bodies of Example 7 and Example 8. FIG. 8 shows the reflectance profile of the thermochromic body of Example 8.

  As shown in FIG. 7, in Example 7, the maximum transmittance is 55.5% at a wavelength of 616 nm, and the transmittance at a wavelength of 500 nm is 47.7%, which exceeds 40%. In Example 8, the maximum transmittance is 57.5% at a wavelength of 654 nm, and the transmittance at a wavelength of 500 nm is 42.2%, which exceeds 40%. Furthermore, as shown in FIG. 8, the wavelength at which the minimum reflectance is 10.0% in Example 7 is 362 nm, and the wavelength at which the minimum reflectance is 8.9% in Example 8 is 374 nm. In this case, it was found that the wavelength was lower than the wavelength showing the maximum transmittance.

(Comparative Example 6)
Except that the optical film thickness of the zinc oxide thin film of the first thin film layer thicker than lambda _0/4, was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, for the optical film thickness of the vanadium dioxide thin film of the second thin film layer and the silicon oxide thin film of the third thin film layer, the wavelength λ ₀ is fixed at 300 nm, and only the zinc oxide thin film has the wavelength λ ₁ made thick so that the 900nm equivalent optical thickness λ _1/4.

  In FIG. 7, the transmittance | permeability profile of the thermochromic body of the comparative example 6 is shown. FIG. 8 shows the reflectance profile of the thermochromic body of Comparative Example 6.

  As shown in FIG. 7, in Comparative Example 6, the maximum transmittance was 56.0% at a wavelength of 752 nm, but the transmittance at a wavelength of 500 nm was found to be only 38.5%, which is lower than 40%. In addition, as shown in FIG. 8, in the comparative example 6, the wavelength which shows the minimum reflectance 6.8% is 384 nm, and it turned out that it is a lower wavelength unlike the wavelength which shows the maximum transmittance | permeability.

(Comparative Example 7)
Except that the optical film thickness of the zinc oxide thin film of the first thin film layer is thinner than lambda _0/4, it was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, for the optical film thickness of the vanadium dioxide thin film of the second thin film layer and the silicon oxide thin film of the third thin film layer, the wavelength λ ₀ is fixed at 300 nm, and only the zinc oxide thin film has the wavelength λ ₁ It was thin like a 200nm equivalent optical thickness λ _1/4.

  In FIG. 7, the transmittance | permeability profile of the thermochromic body of the comparative example 7 is shown. FIG. 8 shows the reflectance profile of the thermochromic body having the three-layer structure of Comparative Example 7.

  As shown in FIG. 7, in Comparative Example 7, the transmittance at a wavelength of 500 nm is 48.2%, which exceeds 40%, but the maximum transmittance at a wavelength of 606 nm remains as low as 49.6%. As shown in FIG. 8, in Comparative Example 7, the wavelength showing the minimum reflectance of 7.7% is 378 nm, which is lower than the wavelength showing the maximum transmittance.

Thus, when the optical film thickness of the zinc oxide thin film only of the first thin film layer is thicker than lambda _0/4, as shown in the results of Examples 1, 7, 8, the wavelength lambda ₁ is 300 serving as an underlying film In the case of 700 nm, the transmittance at a wavelength of 500 nm exceeded 40%. However, as shown in the results of Comparative Example 6, the wavelength lambda ₁ is below 40% for 900 nm.

Meanwhile, as shown in the results of Comparative Example 7, and the wavelength lambda ₁ thinner than the first optical film thickness of the thin film layer lambda _0/4 as 200 nm, can not be sufficiently obtained improvement in transmittance in the visible light region.

Example 1,7,8, from the results of Comparative Examples 6 and 7, three-layer film to fix the wavelength lambda ₀ of the thermochromic material having a first optical thickness of the thin film layer only lambda _0/4 be thicker, specifically, in the visible light region of the thermochromic material be made thicker to ₁ the optical film thickness lambda _1/4 lambda is in the range of equivalent 300~700nm is equipped with a three-layer film It was found to be effective in improving the transmittance.

(Example 9 and Example 10)
Except that the optical film thickness of the silicon oxide thin film is a third thin film layer is thicker than lambda _0/4, was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, as for the optical film thickness of the zinc oxide thin film that is the first thin film layer and the optical film thickness of the vanadium dioxide thin film that is the second thin film layer, the wavelength λ ₀ is fixed at 300 nm, Only the silicon oxide thin film of this thin film layer was thickened so that the wavelength λ ₃ would be an optical film thickness corresponding to 500 nm (Example 9) and 700 nm (Example 10).

  FIG. 9 shows transmittance profiles of the thermochromic bodies of Example 9 and Example 10. FIG. 10 shows the reflectance profiles of the thermochromic bodies of Example 9 and Example 10.

  As shown in FIG. 9, in Example 9, the maximum transmittance is 58.6% at a wavelength of 614 nm, and the transmittance at a wavelength of 500 nm is 51.5%, which exceeds 40%. In Example 10, the maximum transmittance is 62.0% at a wavelength of 704 nm, and the transmittance at a wavelength of 500 nm is 43.0%, which exceeds 40%. Furthermore, as shown in FIG. 10, in Example 9, the wavelength indicating the minimum reflectance of 12.4% is 510 nm, and in Example 10, the wavelength indicating the minimum reflectance of 10.7% is 734 nm. In any case, it was found that the wavelength was relatively close to the wavelength exhibiting the maximum transmittance.

(Comparative Example 8)
Except that the optical film thickness of the silicon oxide thin film is a third thin film layer is thicker than lambda _0/4, was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, for the optical film thickness of the zinc oxide thin film as the first thin film layer and the optical film thickness of the vanadium dioxide thin film as the second thin film layer, the wavelength λ ₀ is fixed at 300 nm, only the silicon oxide thin film layer, wavelength lambda ₃ was thickened to have an optical thickness of lambda _3/4 of the corresponding 900 nm.

  FIG. 9 shows a transmittance profile of the thermochromic body of Comparative Example 8. FIG. 10 shows the reflectance profile of the thermochromic body of Comparative Example 8.

  As shown in FIG. 9, in Comparative Example 8, the maximum transmittance was 59.7% at a wavelength of 800 nm, but the transmittance at a wavelength of 500 nm was found to be only 37.9%, which is less than 40%. As shown in FIG. 10, in Comparative Example 8, it was found that the wavelength showing the minimum reflectance of 9.2% was 340 nm, which is lower than the wavelength showing the maximum transmittance.

(Comparative Example 9)
Except that the optical thickness of the silicon oxide thin film of the third thin film layer is thinner than lambda _0/4, it was treated in the same manner as in Example 1 to produce a thermochromic material. Specifically, for the optical film thickness of the zinc oxide thin film of the first thin film layer and the optical film thickness of the vanadium dioxide thin film of the second thin film layer, the wavelength λ ₀ is fixed at 300 nm and the third thin film layer Only the silicon oxide thin film was thinned so that the wavelength λ ₃ would be an optical film thickness equivalent to 200 nm.

  FIG. 9 shows a transmittance profile of the thermochromic body of Comparative Example 9. FIG. 10 shows the reflectance profile of the thermochromic body of Comparative Example 9.

  As shown in FIG. 9, in Comparative Example 9, the transmittance at a wavelength of 500 nm is 45.7%, which exceeds 40%, but the maximum transmittance at a wavelength of 620 nm is found to be a low value of 47.5%. . As shown in FIG. 10, in Comparative Example 9, it was found that the wavelength showing the minimum reflectance of 5.5% was 266 nm, which was lower than the wavelength showing the maximum transmittance.

Thus, to fix the wavelength lambda ₀ to 300 nm, if the optical film thickness of only the silicon oxide based thin film of the third thin film layer is thicker than lambda _0/4, as shown in results of Examples 1, 9, 10 to, in the case the wavelength lambda ₃ of 300~700nm is transmittance at a wavelength of 500nm exceeds 40%, as shown in the results of Comparative example 8, below 40% when the wavelength lambda ₃ of 900nm It was.

On the other hand, improved when the optical film thickness of the silicon oxide thin film of the third thin film layer is thinner than lambda _0/4, as shown in Comparative Example 9, and the wavelength lambda ₃ to 200 nm, the transmittance in the visible light region I can't let you.

From the results of Examples 1, 9, 10 and Comparative Examples 8 and 9, the wavelength λ _{0 of the} thermochromic body provided with the three-layer laminated film is fixed, and the optical film thickness of only the silicon oxide thin film of the third thin film layer is obtained. thicker than λ _0/4, the optical thickness λ _3/4 λ is by increasing the range of equivalent 300 to 700 nm, was found to be effective in improving the transmittance of the visible light region.

(Example 11)
Except having changed the 1st thin film layer into the aluminum addition zinc oxide thin film, the process similar to Example 1 was performed and the thermochromic body was manufactured. At this time, the amount of aluminum added to the zinc oxide thin film was 0.047 in terms of the Al / (Zn + Al) atomic ratio.

  In FIG. 11, the profile of the transmittance | permeability of the thermochromic body of Example 11 is shown. FIG. 12 shows the reflectance profile of the thermochromic body of Example 11.

  As shown in FIG. 11, the maximum transmittance is 52.1% at a wavelength of 574 nm, and the transmittance at a wavelength of 500 nm is 48.9%, which exceeds 40%. Furthermore, as shown in FIG. 12, the wavelength exhibiting the minimum reflectance of 7.5% is 388 nm, which is different from the wavelength exhibiting the maximum transmittance, which is a lower wavelength.

  Thus, in the thermochromic body provided with the three-layer laminated film, even when the first thin film layer is changed from the zinc oxide thin film to the aluminum-added zinc oxide thin film which is the same zinc oxide-based thin film, the wavelength is 400 to 500 nm. As for the transmittance and reflectance on the short wavelength side of the visible light region, it was found that the first thin film layer obtained high transmittance as well as the thermochromic body which is a zinc oxide thin film, and the reflectance was reduced. .

(Example 12 and Example 13)
Except that thickened optical thickness of the silicon oxide thin film of the first thin film layer optical thickness and the third thin film layer from the lambda _0/4, it was treated in the same manner as in Example 11, producing the thermochromic material did.

Specifically, with respect to the optical film thickness of the vanadium dioxide thin film of the second thin film layer, the wavelength λ ₀ is fixed to 300 nm, and the first thin film layer and the third thin film layer have wavelengths λ ₁ and λ ₃ both 400 nm (example 12), 500 nm (example 13) or equivalent having an optical thickness of lambda _1/4, and thick so that lambda _3/4.

  FIG. 11 shows transmittance profiles of the thermochromic bodies of Examples 12 and 13. FIG. 12 shows the reflectance profiles of the thermochromic bodies of Example 12 and Example 13.

  As shown in FIG. 11, in Example 12, the maximum transmittance is 57.9% at a wavelength of 610 nm, and the transmittance at a wavelength of 500 nm is 50.9%, which exceeds 40%. In Example 13, it was found that the maximum transmittance was 63.1% at a wavelength of 652 nm, and the transmittance at a wavelength of 500 nm was 45.7%, exceeding 40%. Furthermore, as shown in FIG. 12, in Example 12, the wavelength showing the minimum reflectance of 7.9% is 479 nm, and in Example 13, the wavelength showing the minimum reflectance of 6.0% is 592 nm. In this case, it was found that the wavelength was lower than the wavelength showing the maximum transmittance.

Thus, thicker than the first first both lambda _0/4 optical thickness of the silicon oxide based thin film of the optical thickness and the third thin layer of a thin film layer of aluminum doped zinc oxide thin film layer Even in the case where the first thin film layer is a zinc oxide thin film, the transmittance and reflectance on the short wavelength side of the visible light region having a wavelength of 400 to 500 nm are effective in improving the transmittance in the visible light region. I found out that

(Example 14)
Except having changed the 1st thin film layer into the gallium addition zinc oxide thin film, the process similar to Example 1 was performed and the thermochromic body was manufactured. At this time, the amount of gallium added to the zinc oxide thin film was 0.050 in terms of the Ga / (Zn + Ga) atomic ratio.

  The transmittance and reflectance profiles of the thermochromic body of Example 14 are the transmittance profile of the thermochromic body using the aluminum-added zinc oxide of Example 11 shown in FIG. 11, and the aluminum of Example 11 shown in FIG. The reflectance profiles of thermochromic bodies using added zinc oxide were almost the same curves.

(Example 15 and Example 16)
Except that thicker than the first both lambda _0/4 optical thickness of the silicon oxide thin film of the optical thickness of the gallium-doped zinc oxide thin film layer and the third thin film layer, as in Example 14 The process was performed and the thermochromic body was manufactured. Specifically, with respect to the optical film thickness of the vanadium dioxide thin film of the second thin film layer, the wavelength λ ₀ is fixed to 300 nm, and the first thin film layer and the third thin film layer have any of the wavelengths λ ₁ and λ _3. also 400 nm (example 15), 500 nm (example 16) equivalent optical thickness λ _1/4, and thick so that lambda _3/4.

  The transmittance profiles of the thermochromic bodies of Example 15 and Example 16 were almost the same curves as the profiles of the thermochromic bodies using aluminum-added zinc oxide of Example 12 and Example 13 shown in FIG. 11, respectively. . Further, the reflectance profiles of the thermochromic bodies of Examples 15 and 16 are almost the same curves as the profiles of the thermochromic bodies using the aluminum-added zinc oxide of Examples 12 and 13 shown in FIG. 12, respectively. there were.

Thus, as is clear from the results of Examples 14 to 16, even when the base film of the first thin film layer is changed from the zinc oxide thin film to the gallium-doped zinc oxide thin film of the same zinc oxide-based thin film, aluminum Almost the same result as in the case of the additive zinc oxide thin film was obtained, and it was found that, as in the case of the first thin film layer being the zinc oxide thin film, high transmittance was obtained and the reflectance was reduced. Further, by increasing from the first optical film thickness and the third both lambda _0/4 optical thickness of the silicon oxide based thin film of the thin film layer of the thin-film layer of gallium-doped zinc oxide thin film, in the visible light region It was found to be effective in improving the transmittance.

(Example 17)
A thermochromic body was produced in the same manner as in Example 1 except that the vanadium dioxide thin film of the second thin film layer was changed to a tungsten-added vanadium dioxide thin film. The tungsten addition amount of the vanadium dioxide thin film of the second thin film layer was set to 0.015 in terms of the tungsten atom number ratio represented by W / (V + W).

  The transmittance and reflectance profiles of the thermochromic body of Example 17 at room temperature and 80 ° C. were almost the same curve as the transmittance profile of the thermochromic body of Example 1 shown in FIG. 2-4. The transition temperature was 32 ° C.

(Example 18)
A thermochromic body was manufactured in the same manner as in Example 1 except that the second thin film layer was changed to a molybdenum-added vanadium dioxide thin film. The amount of tamolybdenum added to the second thin film layer was 0.032 in terms of the number of molybdenum atoms expressed by Mo / (V + Mo).

  The transmittance and reflectance profiles of the thermochromic body of Example 18 at room temperature and 80 ° C. were substantially the same curves as the transmittance and reflectance profiles of the thermochromic body of Example 1 shown in FIG. 2-4. .

  As apparent from the results shown in Examples 17 and 18, the second thin film was obtained even when the vanadium dioxide thin film of the second thin film layer of Example 1 was changed to a tungsten-added vanadium dioxide thin film or a molybdenum-added vanadium dioxide thin film. Almost the same result as in the case where the layer is a vanadium dioxide thin film was obtained, and it was found that high transmittance was obtained and reflectance was reduced.

  The conditions and results of Examples 1 to 19 and Comparative Examples 1 to 9 are summarized in [Table 1].

  11 first thin film layer, 12 second thin film layer, 13 third thin film layer, 20 substrate

Claims (10)

A zinc oxide-based thin film as a base film formed on a substrate;
A vanadium dioxide thin film formed on the zinc oxide thin film;
A silicon oxide thin film formed on the vanadium dioxide thin film,
The wavelength lambda ₀ is 200 to 400 nm, the optical thickness of the zinc oxide based thin film is λ _0/4, the optical thickness of the vanadium dioxide film is λ _0/2, the silicon oxide film thermochromic body having an optical thickness which is a λ _0/4. The zinc oxide-based thin film is a thin film made of zinc oxide, or a thin film formed by adding one or more elements selected from an element group consisting of aluminum, gallium, boron, and indium to zinc oxide. The thermochromic body according to claim 1 , wherein the thermochromic body is present. The vanadium dioxide thin film is formed by adding one or more metal elements selected from a metal element group consisting of tungsten, molybdenum, tantalum, and niobium to a thin film made of vanadium dioxide or vanadium dioxide. The thermochromic body according to claim 1 or 2 , wherein the thermochromic body is a thin film. The vanadium dioxide-based thin film is a thin film formed by adding tungsten to vanadium dioxide, and the content of the tungsten in the vanadium dioxide-based thin film is 0.001 to the atomic ratio represented by W / (V + W). The thermochromic body according to claim 1, wherein the thermochromic body is 0.1. The vanadium dioxide-based thin film is a thin film formed by adding molybdenum to vanadium dioxide, and the content of the molybdenum in the vanadium dioxide-based thin film is 0.001 to 0.001 in terms of the atomic ratio represented by Mo / (V + Mo). The thermochromic body according to claim 1, wherein the thermochromic body is 0.1. A zinc oxide-based thin film as a base film formed on a substrate;
A vanadium dioxide thin film formed on the zinc oxide thin film;
A silicon oxide thin film formed on the vanadium dioxide thin film,
The wavelength lambda ₀ is 200 to 400 nm, lambda ₁ is the larger 700nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _1/4, the optical film of the vanadium dioxide thin film the thickness is λ _0/2, thermochromic material the optical film thickness of the silicon oxide film, which is a λ _0/4. A zinc oxide-based thin film as a base film formed on a substrate;
A vanadium dioxide thin film formed on the zinc oxide thin film;
A silicon oxide thin film formed on the vanadium dioxide thin film,
The wavelength lambda ₀ is 200 to 400 nm, lambda ₃ is a greatly 700nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _0/4, the optical film of the vanadium dioxide thin film the thickness is λ _0/2, thermochromic material the optical film thickness of the silicon oxide film, which is a lambda _3/4. A zinc oxide-based thin film as a base film formed on a substrate;
A vanadium dioxide thin film formed on the zinc oxide thin film;
A silicon oxide thin film formed on the vanadium dioxide thin film,
The wavelength lambda ₀ is 200 to 400 nm, lambda _1, lambda ₃ are both a large 600nm or less than lambda _0, the optical thickness of the zinc oxide based thin film is lambda _1/4, the dioxide the optical thickness of the vanadium-based thin film is λ _0/2, thermochromic material the optical film thickness of the silicon oxide film, which is a lambda _3/4. A heat ray shielding glass comprising the thermochromic body according to any one of claims 1 to 8 . A zinc oxide thin film is formed as a base film on the substrate,
Forming a vanadium dioxide thin film on the zinc oxide thin film;
Forming a silicon oxide thin film on the vanadium dioxide thin film;
The wavelength lambda ₀ is 200 to 400 nm, the optical thickness of the zinc oxide based thin film and λ _0/4, the optical thickness of the vanadium dioxide thin film and λ _0/2, the optical of the silicon oxide film method of manufacturing a thermochromic material, characterized in that the film thickness is λ _0/4.

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