Shirasu structure and manufacturing process for it

Abstract

Shirasu structure (1), which is a light control element (21) that is an antireflection material, wherein the Shirasu structure (1) comprises: a substrate (3) produced from a transparent or semi-transparent body; at least two thin transparent or semi-transparent Shirasu films (5) formed by physical vapor deposition on the substrate (3);and at least two thin transparent or semi-transparent films with a high refractive index (29), the refractive index of which is higher than that of the at least two thin transparent or semi-transparent Shirasu films (5), wherein the at least two thin transparent or semi-transparent Shirasu films (5) and the at least two thin transparent or semi-transparent films with a high refractive index (29) are formed alternately on top of each other in several layers on a surface of the substrate (3), such that the outer layer of the Shirasu structure (1) is a thin transparent or semi-transparent Shirasu film (5).

Description

TECHNICAL AREA

[0001] This invention relates to a Shirasu structure and a manufacturing process for the Shirasu structure, and in particular to a product comprising a substrate, for example, made of glass and a thin Shirasu film formed on the substrate. BACKGROUND

[0002] In recent years, volcanic Shirasu products have attracted attention as a new material with 100% naturalness and with a variety of functions such as deodorizing function, moisture control function, negative ion effect and sick house syndrome prevention function.

[0003] As an application product of a volcanic Shirasu product, a Shirasu structure 201 (see Fig. 9) as an in-house material (interior finishing material), external material (exterior finishing material) or paving material for the preservation of specific effects in practical use.

[0004] The Shirasu structure 2001 has granular or mass Shirasu 203 , formed into a mass state on a substrate 207 using a binder such as an adhesive 205 .

[0005] Technical documents relating to the state of the art include, for example, patent literature 1 and patent literature 2. LIST OF PRINTED PUBLICATIONS Patent Literature

[0006] Patent literature 1: Unexamined Japanese patent application publication 2004-339712 Patent literature 2: unexamined Japanese patent application publication 2008-101436. SUMMARY OF THE INVENTION Problems to be solved by the invention

[0007] The conventional Shirasu structure 201 It has functions such as deodorizing and moisture absorption. It is important to maintain these functions for a long time. The conventional Shirasu structure 201includes the massive Shirasu 203 and therefore has low light transmission and poor optical properties. If the substrate 207 The coating of the Shirasu is intended to provide visibility. 203 at the substrate 207 limited.

[0008] Shirasu applications are primarily in construction, and there is a need to identify new functionalities of Shirasu related to mechanical, thermal, electrical, biofunctional, segregation, and chemical properties, and to develop Shirasu applications that exhibit such functionality. Given these needs, one objective of this invention is to provide a Shirasu structure that, in addition to its deodorizing and moisture-absorbing functions, possesses excellent optical and electrical properties and is capable of maintaining these properties over a long period against aging. Another objective of this invention is to provide a manufacturing process for such a Shirasu structure. Means to solve the problems

[0009] A first aspect of this invention is a Shirasu structure that includes a substrate and a thin Shirasu film formed by vapor deposition on the substrate.

[0010] In connection with the Shirasu structure of the first aspect, a second aspect of this invention forms the thin Shirasu film by directly depositing metal oxides that form Shirasu onto the substrate.

[0011] In connection with the Shirasu structure of the first or second aspect, a third aspect of this invention makes the substrate from a transparent or semi-transparent material.

[0012] A fourth aspect of this invention configures the Shirasu structure of the first aspect such that the Shirasu structure is a light-controlling element, the substrate is a first conductive film, the thin Shirasu film is formed on a surface of a chromogenic reduction film formed on a surface of the substrate, a chromogenic oxidation film is formed on a surface of the thin Shirasu film, a second conductive film is formed on a surface of the chromogenic oxidation film, and each of the conductive films is made of a transparent or semi-transparent body, or one of the conductive films is made of a transparent or semi-transparent body and the other of a reflective film.

[0013] A fifth aspect of this invention configures the Shirasu structure of the first aspect such that the Shirasu structure is a light-controlling element, the substrate is a first conductive film, the thin Shirasu film is formed on a surface of a chromogenic oxidation film formed on a surface of the substrate, a chromogenic reduction film is formed on a surface of the thin Shirasu film, a second conductive film is formed on a surface of the chromogenic reduction film, and each of the conductive films is made of a transparent or semi-transparent body, or one of the conductive films is made of a transparent or semi-transparent body and another of a reflective film.

[0014] A sixth aspect of this invention configures the Shirasu structure of the first aspect such that the Shirasu structure is an antireflection material, the substrate is made from a transparent or semi-transparent body, and the thin Shirasu film and a thin film with a high refractive index, the refractive index being higher than that of the thin Shirasu film, are formed alternately on top of each other in a plurality of layers on a surface of the substrate.

[0015] A seventh aspect of this invention is a manufacturing process for the Shirasu structure according to any of the first to sixth aspects. The process uses as a material forming a thin film for physical vapor deposition granular or bulk Shirasu, or a sintered body of a specific size formed by sintering granular or bulk Shirasu. EFFECTS OF THE INVENTION

[0016] This invention is able to specify a Shirasu structure which has deodorizing and moisture-absorbing functions, optical and electrical properties and a peel resistance such that a thin Shirasu film hardly peels off a substrate for a long time, as well as a manufacturing method for such a Shirasu structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Fig. Figure 1 illustrates a schematic configuration of a Shirasu structure according to an embodiment of this invention.

[0018] The Fig. 2(a) and Fig. 2(b) are enlarged views illustrating a thin Shirasu film of the Shirasu structure according to the embodiment of this invention, wherein Fig. 2(a) describes a surface of the thin Shirasu film, and Fig. 2(b) a surface roughness of the thin Shirasu film along a straight line L of Fig. 2(a) explained.

[0019] Fig. 3 explains microstructures (microstructural changes depending on the shaping conditions) of the thin Shirasu film of the Shirasu structure according to the embodiment of this invention.

[0020] Fig. Section 4 describes section microstructures of the thin Shirasu film of the Shirasu structure according to the embodiment of this invention.

[0021] Fig. Figure 5 illustrates a schematic configuration of a sputtering system.

[0022] Fig. Section 6 describes a light control element according to an embodiment of this invention.

[0023] Fig. 7 describes a light control element according to an embodiment of this invention.

[0024] Fig. Section 8 describes a light control element according to an embodiment of this invention.

[0025] Fig. Figure 9 explains a schematic configuration of a Shirasu structure according to the state of the art. METHODS FOR IMPLEMENTING THE INVENTION

[0026] A Shirasu structure 1 according to one embodiment of this invention, as shown in Fig. 1 explains, a substrate 3 , which is formed, for example, into a flat plate, and a thin Shirasu film 5 .

[0027] The thin Shirasu film is formed by physical vapor deposition (PVD) such as sputtering to completely or integrally cover a surface (an area in one thickness direction of the flat substrate). 3 ) of the substrate 3 to cover.

[0028] The thin Shirasu film 5 can be formed to cover at least part of the substrate surface 3 to cover. It can be formed to cover all or part of both surfaces in one thickness direction of the flat substrate. 3to cover the substrate 3 It can have a different shape than the plate shape.

[0029] The Shirasu structure 1 It can be an interior building material, an exterior building material, or a paving material.

[0030] Volcanic Shirasu product, used as the starting material for the thin Shirasu film 5 Its purpose is explained.

[0031] The volcanic Shirasu product forms the Shirasu Plateau. The Shirasu Plateau extends from Kagoshima Prefecture to a southern part of Miyagi Prefecture in Japan and has a maximum thickness of 150 meters.

[0032] The Shirasu volcanic soil was created when an enormous pyroclastic flow accumulated in a single mass without mixing with other soil types, forming a thick stratum on the Shirasu plateau. A general type of soil consists of powdery rock mixed with various organic matter created by the actions of plants and microorganisms.

[0033] On the other hand, a volcanic Shirasu product is a powder of magma before it has formed into rocks and contains essentially no nutrients (organic matter). A volcanic Shirasu product is a high-purity inorganic ceramic material sintered from magma at very high temperatures. The volcanic Shirasu product is porous and contains volcanic glass as its main component and 60% to 80% silica components.

[0034] Shirasu, i.e., volcanic shirasu product (e.g., Takachiho-shirasu, found in the Takachiho Mountains of Kyushu, Japan), is explained in detail. An analytical result expressed as a weight percent of Takachiho-shirasu is mentioned below: 2.7% combustion loss, 67.8% SiO2, 15.1% Al2O3, 3.7% Na2O, 2.2% CaO, 2.5% Fe2O3, 2.2% K2O, 0.27% TiO2, 0.06% MnO, 0.58% MgO, 0.03% P2O5, 0.20% SO3 and less than 0.001% Cl – .

[0035] The combustion loss is due to sulfur trioxide (SO3) and is measured according to JIS R5202. Silicon dioxide (IV) (SiO2) is measured according to a aggregation weight-absorption combination method. Aluminum oxide (Al2O3), iron oxide (III) (Fe2O3), titanium dioxide (IV) (TiO2), calcium oxide (CaO), magnesium oxide (MgO), sodium oxide (Na2O), potassium oxide (K2O), manganese oxide (MnO), and phosphorus pentoxide (P2O5) are measured according to hydrofluoric acid-nitric acid-perchloric acid decomposition ICP emission spectrometry. Chloride ions (Cl) – ) are elution according to the remark 13 of the Ministry of the Environment and measured by measuring a test solution according to ion chromatography.

[0036] Shirasu other than Takachiho-Shirasu (e.g. Kagoshima-Shirasu) or Shirasu with the same composition as Takachiho-Shirasu may be used instead of Takachiho-Shirasu.

[0037] The main components of Shirasu are silica and aluminum oxide. Shirasu also contains plagioclase, quartz, titanium oxide, and similar substances. Many small air bubbles are found beneath the Shirasu grains.

[0038] Smooth, dry, powdery shirasu retains very little water and is therefore unsuitable for rice plants. During torrential rains, shirasu easily causes landslides and is therefore considered a problem.

[0039] The Shirasu structure 1 will be explained in detail. The substrate 3 the Shirasu structure 1 is a transparent or semi-transparent material (for example, a glass plate).

[0040] In contrast to the state of the art, the thin Shirasu film uses 5 It contains no binding agent like an adhesive and is formed by the direct deposition of metal oxides and the like, which constitute Shirasu, onto the substrate. 3 For example, the thin Shirasu film5 produced solely from Shirasu components. The thickness of the thin Shirasu film 5 is approximately 5 nm to 100 μm. The thin Shirasu film 5 can be formed in a thickness range of 1 nm to 1 mm or 1 nm to 10 mm.

[0041] A thin film is a film that is thin and demonstrates properties that differ from those of a large mass.

[0042] The thin Shirasu film 5 on the substrate 3 It looks flat to the naked eye. Under magnification, as in Fig. As explained in section 2, it has subtle irregularities. For example, in a scan area of ​​1 × 1 μm on the thin Shirasu film. 5 Fine holes are confirmed.

[0043] The thin Shirasu film 5 Formed by physical vapor deposition such as sputtering, its microstructure changes depending on the formation conditions.

[0044] As in Fig. As explained in section 3, a change in the temperature Ts (degrees on the Kelvin scale) of the substrate (base plate) leads to 3 and a pressure of the inert gas (e.g. argon gas Ar) to change the microstructure of the thin Shirasu film 5 Tm is the melting point of a thin film forming material (Target 11 in Fig. 5).

[0045] A Zone 1 (ZONE-1), explained in Fig. 3, is a microstructure zone that is created when the argon gas pressure is high and the temperature of the substrate is high. 3 is low. A cross-section of it is in Fig. 4(a) modeled. The thin Shirasu film 5 , formed according to the conditions of Zone 1, involving fine columns and many cavities or holes, with a reduction in density.

[0046] A Zone T (ZONE-T), explained in Fig. 3, is a microstructure zone that is created when the argon gas pressure is low and the temperature of the substrate is low. 3is low. A cross-section of it is in Fig. 4(b) modeled. The thin Shirasu film 5 , formed according to the conditions of zone T, includes fine columns and fewer cavities, forming a dense film.

[0047] A Zone 2 (ZONE-2), explained in Fig. 3, is a microstructure zone that is created when the temperature of the substrate 3 is high. A cross-section of it is shown in Fig. 4(c) modeled. The thin Shirasu film 5 , formed according to the conditions of zone 2, involves fine columns and grains that are larger than those of zone T.

[0048] A Zone 3 (ZONE-3), explained in Fig. 3, is a microstructure zone that is created when the temperature of the substrate 3 remains high. A cross-section of this is in Fig. 4(d) modeled. The thin Shirasu film 5, formed according to the conditions of zone 3, is isotropic and nearly in a mass state.

[0049] The thin Shirasu film 5 the Shirasu structure 1 It can be formed in any of the zones mentioned above. It is preferred that its formation be appropriately selected according to its use.

[0050] A manufacturing process (coating process for the thin Shirasu film) of the Shirasu structure 1 The process is explained. It uses a sputtering system. 7 , which in Fig. 5 is explained and integrally the thin Shirasu film 5 by sputtering on a surface of the substrate 3 educates.

[0051] To perform sputtering, a target is used. 11 , which serves as material (educational material for the film) for the formation of the thin Shirasu film 5 on the substrate 3 serves in a vacuum chamber 9arranged. A high voltage is applied, so that an ionized inert gas (argon gas) is present in the vacuum chamber. 9 ) on the target 11 hits.

[0052] This leads to the removal of atoms from the surface of the target. 11 The atoms reach the substrate. 3 , inside the vacuum chamber 9 is arranged, and form the thin Shirasu film 5 .

[0053] The target 11 It is produced by sintering granular or bulk (powdered or powdery) shirasu into a sintered body (an integrated body with a large number of shirasu grains or masses) of a specific size. Granular or bulk shirasu can be used as a target as is. 11 be used.

[0054] In the above explanation, only an inert gas is introduced into the vacuum chamber. 9In addition to the inert gas, an active gas (for example, oxygen O2) can be introduced. When the active gas is introduced, the atoms ejected (of the metal oxides that make up the shirasu) from the shirasu (the material for forming the thin film) react with the active gas, and the reacted compounds condense to form a thin shirasu film. 5 on the substrate 3 low.

[0055] In this way the Shirasu structure is created. 1 formed by physical vapor deposition, which forms the thin Shirasu film 5 on the surface of the substrate 3 strikes down. The Shirasu structure 1 Shirasu has original functions such as deodorizing and moisture-absorbing effects. Because of the Shirasu structure 1 Since it contains no binder, these functions last for a long time.

[0056] The deodorizing function of the Shirasu structure 1This is achieved when titanium oxide, which is in the thin Shirasu film 5 It contains a photocatalyst that decomposes odor components. The Shirasu structure 1 It is porous, so that micropores and mesopores achieve an adsorption effect, to demonstrate the moisture-absorbing function.

[0057] In accordance with the state of the art, which is in Fig. As explained in section 9, the Shirasu structure is included. 201 the granular or massive Shirasu 203 and therefore the adhesive 205 such as a binding agent is required for applying the shirasus 203 on the substrate 207 Time and effort are required to form a thin film of Shirasu. 203 on the substrate 207 On the other hand, the thin Shirasu film 5 on the Shirasu structure 1Formed by physical vapor deposition. The Shirasu structure can be produced using simple methods, without requiring the time and effort of current technology.

[0058] In the Shirasu structure 1 is the substrate 3 a glass plate on which the thin Shirasu film 5 This configuration improves optical properties (for example, the transmission of visible light).

[0059] This invention focuses on a thin film instead of grains or mass and uses sputtering as a technique for forming a thin film, the thin Shirasu film. 5(on the nanometer scale). Sputtering is an advantageous process for forming a thin film that maintains microstructures controlled at the atomic level, exhibits good quality and adhesion, and can be produced over a large, uniform area. By utilizing the advantages of sputtering, the thin Shirasu film is produced. 5 on the substrate 3 deposited without a binding agent.

[0060] This invention makes positive use of the physical properties of the thin Shirasu film, maintains the excellent functions such as deodorizing and moisture-absorbing properties of the thin Shirasu film, and achieves high transmission capacity when Shirasu is applied to the substrate (glass plate). 3 is applied, which is necessary to maintain visibility.

[0061] This will be explained in detail. The thin Shirasu film 5, formed by sputtering on a surface of the substrate (glass plate) 3 It has fine irregularities. The steps (heights in some cases) of these fine irregularities are smaller than the wavelength of visible light, and therefore visible light is transmitted through the Shirasu structure. 1 without interruption through the thin Shirasu film 5 (as if the thin Shirasu film 5 (would not exist).

[0062] According to the Shirasu structure 1 will the surface of the glass plate 3 with the thin Shirasu film 5 , which exhibits hydrophilicity, covers and therefore hardly a veil forms from the Shirasu structure when the Shirasu structure 1 with the substrate 3 made from a glass plate used as window glass or as a mirror.

[0063] If the Shirasu structure 1When used as an interior finishing material, it demonstrates deodorizing, humidity-controlling, sterilizing and negative ion-generating functions, creating a comfortable living environment.

[0064] A modern house is very draft-free, and even with some ventilation, daily life can lead to the accumulation of various substances, creating odors and humidity. To counteract this, the Shirasu structure absorbs excess moisture when humidity rises and releases it when humidity falls, thus automatically regulating indoor humidity. The Shirasu structure also deodorizes. 1 It quickly removes cigarette and pet odors and safely adsorbs chemical substances such as formaldehyde released from furniture and the like in the house.

[0065] If the Shirasu structure 1When used as an outer material, it demonstrates water resistance and moisture permeability, resulting in an attractive, warm, and practical appearance. The Shirasu structure 1 resists ultraviolet rays and exhibits essentially no color fading or degradation.

[0066] During the creation of the Shirasu structure 1 A sintered body made of granular or bulk Shirasu is used as the target. Such a Shirasu target is easy to handle.

[0067] In the explanation above, a physical vapor precipitate directly forms the thin Shirasu film. 5 on a surface of the substrate. Instead, another layer can be intermediately deposited to indirectly create the thin Shirasu film. 5 on the substrate 3 to form.

[0068] A product created by indirectly forming the thin Shirasu film 5 on the substrate 3The process of formation is explained.

[0069] The Shirasu structure 1 , formed by indirectly forming the thin Shirasu film 5 on the substrate 3 is a light control element (control element for visible light) 21 , explained in the Fig. 6 and Fig. 7(a). The light control element 21 for example, it is formed into a rectangular flat plate (see Fig. 7(a)).

[0070] The light control element 21 is an element that utilizes an EC phenomenon, where the color of the substance changes due to an oxidation-reduction reaction, and includes a substrate 3 , a chromogenic reduction film 3 , a thin Shirasu film 5 , a chromogenic oxidation film 25 and a second lead film 27 .

[0071] The substrate 3forms a first conducting film (thin film). On a surface of the first conducting film 3 A physical vapor deposition process such as sputtering is carried out to directly form the chromogenic reduction film (thin film). 23 in contact with the first leading film 3 The chromogenic reduction film 23 is produced, for example, from tungsten oxide (VI) (WO3).

[0072] The thin Shirasu film 5 is transparent or semi-transparent and is produced by physical vapor deposition such as sputtering directly onto and in contact with a surface of the chromogenic reduction film. 23 educated.

[0073] On a surface of the thin Shirasu film 5 A physical vapor deposition process such as sputtering is carried out to form the chromogenic oxidation film (thin film). 25 directly on and in contact with the thin Shirasu film 5The chromogenic oxidation film 25 is, for example, made of iridium oxide and tin oxide (IV) (IrO x + SnO2). Directly on and in contact with a surface of the chromogenic oxidation film. 25 is the second lead film 27 educated.

[0074] Each of the leading films 3 and 27 is transparent or semi-transparent and is formed, for example, from a transparent conductive film (ITO (indium tin oxide); indium oxide-tin; tin-doped indium oxide).

[0075] It is preferred that the thin Shirasu film 5 from Zone 1 (ZONE-1), explained in Fig. 3, or from Zone T (ZONE-T), explained in Fig. 3, is.

[0076] The operation of the light control element 21 will be explained.

[0077] The thin Shirasu film 5 It has subtle irregularities as mentioned above and within the thin Shirasu film. 5There are fine holes for holding water (H2O).

[0078] If there is tension between the first leading film 3 and the second lead film 27 as in Fig. 6 is explained, is imposed, monovalent cations (for example hydrogen ions H) enter + ) the chromogenic reduction film 23 , creating connections (H x WO3), for dyeing the chromogenic reduction film 23 This leads to a reduction in the transmission of visible light through the chromogenic reduction film. 23 The tension that existed between the first leading film 3 and the second lead film 27 imposed also causes monovalent anions (e.g., hydroxide ions OH) to form. – ) the chromogenic oxidation film 25 enter, generating compounds (Ir(OH) n+x As a result, the chromogenic oxidation film is formed. 25colored, reducing the transmission of visible light of the chromogenic oxidation film 25 The colored state persists even after the voltage is applied.

[0079] If a tension contrary to the case of Fig. 6 is imposed, the chromogenic reduction film 23 and the chromogenic oxidation film 25 colorless and transparent or semi-transparent, with increased transmission of visible light. The colorless and transparent or semi-transparent state persists even after the voltage is removed.

[0080] ECD (electrochromic display) according to a prior art uses the EC phenomenon that the color of the substance changes depending on an oxidation-reduction reaction and uses a liquid or fluid (or gel) body as the electrolyte film instead of the thin Shirasu film. 5 used.

[0081] Conventional ECDs, which use a liquid electrolyte film, require liquid or fluid handling during manufacturing processes, thus complicating their production. Additionally, conventional ECDs carry a risk of fluid leakage due to aging or depending on the operating environment. To address this, a prior art ECD uses a solid electrolyte film containing a rare-earth metal.

[0082] The ECD, which uses a solid electrolyte film, is expensive because it uses a rare earth metal. On the other hand, the light control element is based on 21 based on the finding that Shirasu can be used as an electrolyte film, and uses the thin Shirasu film 5 as a solid electrolyte film of the light control element 21 Because the light control element 21Since it does not use any rare earth metal, it is cost-effective, and compared to the conventional solid electrolyte film, it demonstrates a higher ionic conductivity.

[0083] In contrast to the conventional ECD, which uses a liquid electrolyte film, the light control element includes 21 simpler manufacturing processes and does not cause fluid leakage due to aging or depending on usage environments.

[0084] The light control element 21 It can be used as a light-blocking element that can easily switch between transmitting and blocking visible light. The light-blocking element is suitable for building or aircraft windows.

[0085] The thin Shirasu film 5It can be formed using a combination sputtering process, particularly RAS (radically assisted sputtering), which is used as a technique for creating a thin optical film at high speed and low temperature. This technique is capable of quickly producing the thin Shirasu film. 5 to form and increase the temperature of the substrate 3 and to suppress the like.

[0086] The RAS technique is described, for example, in the Japanese unexamined patent applications 2001-234338, H11-279757 and H11-256327.

[0087] The thin Shirasu film 5 can be formed into a single continuous product, as in Fig. 7(a) is explained. In this case, the light control element 21 Can be used as a light-blocking component as mentioned above. As in Fig. As explained in 7(b), the first leading film 3 , the chromogenic reduction film 23, the thin Shirasu film 5 , the chromogenic oxidation film 25 and the second leading film 27 subdivided and into many fine segments 31 can be divided so that an individual tension is applied to each segment. 31 imposed. In this case, the light control element 21 Can be used as an image display unit instead of an LCD.

[0088] In Fig. 6. The chromogenic reduction film 23 and the chromogenic oxidation film 25 be exchanged with each other.

[0089] The Shirasu structure 1 is used as a light control element 21 used the substrate 3 is used as the first leading film, the thin Shirasu film 5 is applied to a surface of the chromogenic oxidation film 25 formed on a surface of the substrate, the chromogenic reduction film 23is applied to a surface of the thin Shirasu film 5 formed, and the second leading film 27 is applied to a surface of the chromogenic reduction film 23 educated.

[0090] One of the leading films 3 and 27 can be created from a transparent or semi-transparent body, and the other (e.g., the first conducting film) 3 ) can be formed from a reflective film to reflect visible light.

[0091] In this case, the first leading film is 3 Produced from Al (aluminum), forming a reflective electrode film. With the first conductive film 3 , which serves as a reflective electrode film, can be the light control element 21 can be used as a glare-free mirror.

[0092] The light control element 21 can be used as an anti-reflective material (anti-reflective plate).

[0093] In this case, the substrate 3 from the anti-reflective material 21 Produced from a transparent or semi-transparent body. In antireflection material. 21 is a surface of the substrate 3 coated with an anti-reflective film (AR coating).

[0094] An example of this is explained in detail. As in Fig. As explained in section 8, it is a thin Shirasu film. 5 ( 5A ) transparent or semi-transparent and directly on and in contact with a surface of the substrate 3 formed directly on and in contact with a surface of the thin Shirasu film. 5 ( 5A ), is a thin film 29 ( 29A ) formed (e.g. titanium oxide (IV) (TiO2), whose refractive index is higher than that of the thin Shirasu film 5 ( 5A The thin film 29 Lenses with a high refractive index are also transparent or semi-transparent.

[0095] Directly on and in contact with a surface of the thin film 29 ( 29A ) with a high refractive index, is a thin Shirasu film 5 ( 5B ) formed by the thin Shirasu film 5 ( 5A ) is different. Directly on and in contact with a surface of the thin Shirasu film. 5 ( 5B ) is a thin film 29 ( 29B ) with a high refractive index (e.g. titanium oxide (IV) (TiO2)), formed by the thin film 29 ( 29A ) with a high refractive index is different.

[0096] The refractive index of the thin Shirasu film 5 is low, around 1.4 to 1.5. The thin film 29 With a high refractive index, it has a high refractive index of approximately 2.0 to 3.0. Due to the AR coating, the total reflectivity is approximately 5%.

[0097] In the explanation above, four layers of thin films are applied alternately to the substrate. 3 formed, i.e. the thin Shirasu film 5A , the thin film 29A with a high refractive index, the thin Shirasu film 5B and the thin film 29B with a high refractive index. This configuration does not limit this invention. The thin Shirasu film 5 and the thin film 29 Materials with a high refractive index can be stacked on top of each other in a multitude of layers on the substrate. 3 be ordered.

[0098] In the above explanation, the thin Shirasu film is mentioned. 5 on a surface of the substrate 3 formed, and on a surface of the thin Shirasu film 5 will the thin film 29 formed with a high refractive index. The thin Shirasu film 5 and the thin film 29Lenses with high refractive indices can be interchanged. This is because they are located on the surface of the substrate. 3 can the thin film 29 formed with a high refractive index, and on a surface of the thin film 29 The thin Shirasu film can be used with a high refractive index. 5 be formed.

[0099] As mentioned above, the AR coating is able to minimize optical loss due to reflection, and is therefore applicable to coating solar cells. Applying the "anti-reflective film" to the cell surface ensures that sunlight is reliably absorbed into the cell.

[0100] The refractive index of the thin Shirasu film is low, approximately 1.4 to 1.5, making it an optimal material for coating solar cells (especially the light condensation lens of a light condensation solar cell). Additionally, the photocatalytic properties of titanium dioxide (TiO2) contained in the thin Shirasu film provide an anti-growth effect on the solar cell.

[0101] If, on the other hand, the growth-inhibiting effect is achieved by forming a thin film of titanium oxide (TiO2), which is a photocatalytic material, instead of the thin Shirasu film on the solar cell, the high refractive index of titanium oxide (TiO2) alters the optical path of a module or condensation lens when the thin film of titanium oxide (TiO2) is in place. In this case, sunlight is not reliably absorbed into the solar cell.

[0102] Within the scope of the invention, this invention is not limited to the embodiments mentioned above. Reference symbol list 1 Shirasu structure 3 Substrat 5, 5A, 5B thin Shirasu film 11 Target 21 Light control element 23 chromogenic reduction film 25 chromogenic oxidation film 27 second leading film 29, 29A, 29B thin film with high reflectance index

Claims

[1] Shirasu structure, encompassing: a substrate, and a thin Shirasu film, formed by physical vapor deposition on the substrate. [2] Shirasu structure according to claim 1, characterized by that the thin Shirasu film is formed by direct deposition of metal oxides onto the substrate, wherein the metal oxides are the main components of volcanic Shirasu ash. [3] Shirasu structure according to claim 1 or 2, characterized by that the substrate is a transparent or semi-transparent material. [4] Shirasu structure according to claim 1, characterized in that: the Shirasu structure is a light-controlling element, the substrate is a first conductive film, and the thin Shirasu film is formed on a surface of a chromogenic reduction film that is formed on a surface of the substrate; a chromogenic oxidation film is formed on a surface of the thin Shirasu film, a second conductive film is formed on a surface of the chromogenic oxidation film; and each of the conducting films is produced from a transparent or semi-transparent body, or one of the conducting films is formed from a transparent or semi-transparent body and the other from a reflective film. [5] Shirasu structure according to claim 1, characterized by that: the Shirasu structure is a light-controlling element, wherein the substrate is a first conductive film and the thin Shirasu film is formed on a surface of a chromogenic oxidation film that is formed on a surface of the substrate; a chromogenic reduction film is formed on a surface of the thin Shirasu film; a second conductive film is formed on a surface of the chromogenic reduction film; and each of the conducting films is produced from a transparent or semi-transparent body, or one of the conducting films is formed from a transparent or semi-transparent body and the other from a reflective film. [6] Shirasu structure according to claim 1, characterized by that: the Shirasu structure is an antireflective material; the substrate is created from a transparent or semi-transparent body; and The thin Shirasu film and a thin film with a high refractive index, whose refractive index is higher than that of the thin Shirasu film, are formed alternately on top of each other in a multitude of layers on a surface of the substrate. [7] Manufacturing process for the Shirasu structure according to any one of claims 1 to 6, characterized bythat a material for forming a thin film used for physical vapor deposition is granular or bulk shirasu, or is a sintered body with a specific base, produced by sintering granular or bulk shirasu.