WO2005059600A1

WO2005059600A1 - Antifogging element

Info

Publication number: WO2005059600A1
Application number: PCT/JP2003/016109
Authority: WO
Inventors: Hideyuki Kikuchi
Original assignee: Murakami Corporation
Priority date: 2003-12-16
Filing date: 2003-12-16
Publication date: 2005-06-30

Abstract

An antifogging element which has excellent antifogging properties and can suppress exothermic body reflection, enabling obtaining excellent images free of catching of exothermic body reflection images and which can be produced with low cost. In particular, antifogging element (1) characterized by comprising transparent substrate member (2); transparent hydrophilic thin film (3) disposed on the front surface side of the transparent substrate member (2) and comprising a photocatalyst reactant and a hydrophilic substance; transparent conductive thin film (4) disposed on the back side of the transparent substrate member (2) and comprising a conductive substance; and transparent reflection preventive thin film (5) disposed on the back side of the transparent conductive thin film (4) and comprising a low refractive index substance.

Description

Description Anti-fog element Technical field

The present invention relates to an antifogging element having an antifogging property on the surface side of a substrate member such as a glass plate, and particularly to an antifogging element configured as a hood glass for a camera.

Background art

Japanese Patent Application Laid-Open No. H07-2632201 (paragraph numbers [00002], [00003], It is proposed in Figure 5 and Figure 6). As shown in Fig. 11 (a), the dew condensation panel 101 as an anti-fog element is formed on the back side of the glass plate 102 in a shape suitable for the heat generating area suitable for preventing dew condensation. Thin-film layer 103 made of tin oxide, zinc oxide, etc., an electrode film 105 connected to this thin-film layer 103 for energization, and a power supply terminal 100 to which a power supply wire 107 is connected. And a protective glass plate 104 provided on the thin film layer 103, the electrode film 105, and the like for preventing and protecting from electric shock. In the dew condensation preventing panel 101, the thin film layer 103 is energized, and the heat generated raises the temperature of the surface of the glass plate 102 to prevent dew condensation.

However, in the dew condensation panel 101, water droplets adhering to the surface of the glass plate 102 have a ball shape due to the water repellency of the glass plate 102. For this reason, even when the thin film layer 103 was energized, the water droplets did not easily evaporate, and the antifogging property was insufficient.

An anti-fog element that has solved such a problem is disclosed in No. 4 (paragraph numbers [0 17], [0 36], Figure 12). As shown in Fig. 11 (b), the window glass for automobiles as an anti-fog element 201 is made of a transparent electrode such as ITO on the front side of a transparent glass substrate 202 constituting the window glass body. film 2 0 4, Ding 1 0 ₂ film 2 0 3 and, overall sequentially deposited porous S i 〇 ₂ film 2 0 3 b has been configured transparent. In this automotive window glass 201, the porous SiO ₂ film 203b exhibits hydrophilicity, and the attached water droplets are spread not in a ball shape but in a thin film shape (the contact area with air is reduced). (It spreads and evaporates easily.) In addition, clip electrodes 205 and 206 are mounted on the upper side and lower side of the laminated body of the transparent glass substrate 202 and the transparent electrode film 204, and the transparent electrode is supplied from the power supply 2007. Ri by the energizing the membrane 2 0 4, and the transparent electrode film 2 0 4 fever, effectively removing the spread water droplets into a thin film shape with porous S i 0 ₂ film 2 0 3 b surface ing. Also, in T i 0 ₂ film 2 O 3 a, photoexcited Ri by the porous S i 0 ₂ film 2 0 3 b the transmitted sunlight other rays, electrons and holes pairs are generated. Then, the electron-positive:? Ri by the tooth pair, organic substances adhering to the porous S i 0 ₂ film 2 0 3 b of the opening is decomposed and removed. Therefore, the hydrophilicity of the porous SiO ₂ film 203 b is prevented from lowering, and the anti-fogging property can be maintained for a long period of time.

However, in the anti-fog element disclosed in Japanese Patent Application Laid-Open No. 10-36144, the porous SiO ₂ film exhibiting hydrophilicity and the transparent electrode film serving as a heating element are provided on the surface side of the transparent glass substrate. , It is possible to remove the fogging generated on the front side of the transparent glass substrate, but it is not possible to remove the fogging generated on the back side of the transparent glass substrate, and the antifogging property is insufficient. There was a problem. In particular, if the anti-fog element is a camera hood glass, the temperature of the inside and outside air of the storage container tends to be different, so the air inside the storage container will be on the back side (inside air side) of the hood glass. The water vapor will condense and cause fogging I'm sorry. In addition, when used in cold regions or high altitudes, the above phenomenon is particularly remarkable.

It is also described that the transparent electrode film is disposed on the back side of the transparent glass substrate.However, since ITO or the like used for the transparent electrode film has a large refractive index, light is not reflected on the transparent electrode film. appear. Therefore, when the anti-fog element is a camera hood glass, the reflected image of the transparent electrode film appears in the camera image transmitted through the anti-fog element, and a good image cannot be obtained. Was.

Further, since the transparent electrode film or the like as a heating element is disposed on the surface side of the transparent glass substrate, the heating element is exposed to the outside air. As a result, it is necessary to consider the durability of the heating element, for example, acid resistance, etc., and there is a problem that the materials and the like constituting the heating element are limited, and the manufacturing cost is increased.

Further, in the anti-fog element of JP-A-07-263210, as in JP-A-10-364144, a thin film layer made of tin oxide, indium oxide or the like is used. When the light is reflected and used for a camera, the reflected image appears in the camera image, and there is a problem that a good image cannot be obtained.

In view of the above, the present invention solves the above-mentioned problem, has excellent anti-fog properties, suppresses reflection of the heating element, and obtains a good image without reflection of the reflection image of the heating element. The purpose is to provide an antifogging element that can be manufactured at low cost. Disclosure of the invention

In the present invention that solves the above problems, a first invention is a transparent substrate member, a transparent hydrophilic thin film provided on the surface side of the transparent substrate member and containing a photocatalytic reaction substance and a hydrophilic substance, A transparent conductive thin film provided on the back surface side of the transparent substrate member and containing a conductive substance; and a further back surface of the conductive thin film And a transparent anti-reflection thin film containing a low-refractive-index substance.

In the present invention, “front side” means a side of the anti-fogging element that comes into contact with the outside air, and “back side” means a side of the anti-fogging element that does not come into contact with the outside air.

According to the configuration, the hydrophilic substance of the hydrophilic thin film imparts hydrophilicity to the surface side of the transparent substrate member, and water droplets attached to the surface side of the transparent substrate member evaporate in a thin film form. Further, when the hydrophilic thin film contains the photocatalytic reactant, electron-hole pairs are generated from the photocatalytic reactant by photoexcitation. The electron and hole pairs react with air and water to produce o ₂ — (superoxide ion) and · OH (hydroxyl radical), which are attached to the hydrophilic thin film by the O and · OH. Organic matter is decomposed and removed. As a result, the hydrophilicity of the hydrophilic thin film does not decrease. In addition, due to the heat generated by the conductive thin film, water droplets attached to the back surface of the transparent substrate member evaporate. In addition, the antireflection film bridges a large difference in refractive index between the conductive thin film and air. Further, since the conductive thin film and the antireflection film are provided on the back surface side of the transparent substrate member, it is not exposed to the outside air, and it is not necessary to consider durability. Further, in the second invention, a transparent first intermediate thin film is provided between the transparent substrate member and the hydrophilic thin film, and the refractive index of the first intermediate thin film is different from the refractive index of the hydrophilic thin film and the transparent thin film. This is configured as an anti-fog element having an intermediate value of the refractive index of the substrate member.

According to the configuration, the first intermediate thin film fills a large difference in refractive index between the hydrophilic thin film and the transparent substrate member. In a third aspect of the present invention, the antireflection thin film is configured as an antifogging element having a laminated structure in which two or more thin films are laminated.

According to the configuration, the large refractive index difference between the conductive thin film and the air is filled by the laminated structure of the antireflection thin film. Further, a fourth invention provides a transparent substrate member, provided on a front surface side of the transparent substrate member, a transparent hydrophilic thin film containing a photocatalytic reactant and a hydrophilic substance, provided on a back surface side of the transparent substrate member. A transparent second intermediate thin film, further provided on the back side of the second intermediate thin film, and a transparent conductive thin film containing a conductive material, wherein the refractive index of the second intermediate thin film is The antifogging element has an intermediate value between the refractive index of the substrate member and the refractive index of the conductive thin film.

According to the above configuration, due to the hydrophilicity of the hydrophilic thin film, water droplets adhered to the surface side of the transparent substrate member evaporate in a thin film shape. In addition, since the hydrophilic thin film contains the photocatalytic reactant, organic substances attached to the hydrophilic thin film are decomposed and removed by electrons and holes generated from the photocatalytic reactant by photoexcitation, and the hydrophilic thin film is removed. Does not decrease in hydrophilicity. In addition, due to the heat generated by the conductive thin film, water droplets attached to the back surface of the transparent substrate member evaporate. In addition, the second intermediate thin film fills a large difference in refractive index between the transparent substrate member and the conductive thin film. Brief Description of Drawings

FIG. 1 (a) is a perspective view showing the configuration of a camera hood, and (b) is a cross-sectional view taken along the line X-X of (a) of the first embodiment of the anti-fog element according to the present invention. FIG. 7C is a schematic diagram showing the configuration of the cross section of the modification of FIG. 5B in an enlarged manner in the width direction. FIG. 2 (a) is a second embodiment of the anti-fogging element according to the present invention, (b) is a third embodiment, and (c) is an enlarged cross-sectional configuration of the fourth embodiment in the width direction. FIG.

FIG. 3 is a spectral transmittance characteristic diagram of the first embodiment of the anti-fog element according to the present invention.

FIG. 4 is a spectral transmittance characteristic diagram of the first embodiment of the antifogging element according to the present invention.

FIG. 5 is a spectral transmittance characteristic diagram of the first embodiment of the anti-fogging element according to the present invention.

FIG. 6 is a spectral transmittance characteristic diagram of a third embodiment of the anti-fogging element according to the present invention.

FIG. 7 is a spectral transmittance characteristic diagram of a third embodiment of the anti-fogging element according to the present invention.

FIG. 8 is a spectral transmittance characteristic diagram of a third embodiment of the antifogging element according to the present invention.

FIG. 9 is a spectral transmittance characteristic diagram of the third embodiment of the antifogging element according to the present invention.

FIG. 10 is a spectral transmittance characteristic diagram of a fourth embodiment of the antifogging element according to the present invention.

FIGS. 11 (a) and (b) are schematic diagrams showing the cross-sectional configuration of a conventional anti-fog element enlarged in the width direction. BEST MODE FOR CARRYING OUT THE INVENTION

Next, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 (a) is a perspective view showing the configuration of a camera hood, and (b) is an enlarged cross-sectional view of the configuration of (a) of the first embodiment of the antifogging element, taken along the line X-X-ray. hand (C) is a schematic diagram showing the cross-sectional configuration of the modification of (b) enlarged in the width direction, FIG. 2 (a) is the second embodiment, and (b) is the third embodiment Form, (c) is a schematic diagram showing a cross-sectional configuration of the fourth embodiment enlarged in the width direction, FIGS. 3 to 5 are spectral transmittance characteristic diagrams of the first embodiment of the anti-fog element, 6 to 9 are spectral transmittance characteristic diagrams of the third embodiment of the anti-fog element, and FIG. 10 is a spectral transmittance characteristic diagram of the fourth embodiment of the anti-fog element. The anti-fog element of the present invention is used as a hood glass for a camera as shown in FIG. 1 (a). However, the anti-fog element of the present invention is not limited to camera hood glass, but may be an element requiring anti-fog properties, for example, window glass for automobiles. FIG. 1 (b) shows a first embodiment of the present invention. As shown in FIG. 1 (b), the anti-fogging element 1 includes a transparent substrate member 2, a hydrophilic thin film 3, a conductive thin film 4, and an anti-reflection thin film 5. Hereinafter, each configuration will be described in detail.

(1) Transparent substrate member

The transparent substrate member 2 is a plate-like substrate containing transparent glass or acrylic resin. The anti-fogging element can take various shapes according to the use status and application, and for example, may be a thin film. In addition, plastics other than acrylic resin can be used as long as the material has transparency, and more preferably, it has heat resistance and insulating properties. Further, the thickness of the transparent substrate member 2 is preferably 1 to 1 Omm.

(2) Hydrophilic thin film

The hydrophilic thin film 3 is a transparent thin film containing a photocatalytic reaction substance and a hydrophilic substance. The hydrophilic property of this hydrophilic substance imparts hydrophilicity to the hydrophilic thin film 3 As a result, the water droplets adhering to the hydrophilic thin film 3 do not become beads but become a thin film, and the anti-fog element 1 has anti-fog properties. Further, it is preferable that the hydrophilic thin film 3 is formed in a porous shape. Due to this porous shape, the wettability of the surface of the hydrophilic thin film 3 is improved by capillary action, and the hydrophilicity is enhanced.

Further, the hydrophilic substance is preferably an inorganic oxide, and more preferably a metal oxide. Metal oxides, for example, an _{_{S i 0 2, A 1 2}} 0 3 or mixtures thereof, these metal oxides show a hydrophilic since it has a hydrophilic OH groups on the surface.

Further, the photocatalytic reaction substance, T i O have Z n O, S N_〇 _2, Z n S, the semiconductor is preferably composed mainly of C d S or mixtures thereof, T i 0 ₂ reactivity, sustained Most preferred in terms of safety and safety. The photocatalytic reactant is photoexcited by irradiation with sunlight or the like (light having energy equal to or greater than the band gap of the semiconductor), and electron-hole pairs are generated in the photocatalytic reactant. The electron-hole pairs react with air and water in the hydrophilic thin film 3 to generate oxidizing O ₂ (superoxide ion) and '〇H (hydroxyl radical). These 0 ₂ -and · OH efficiently decompose and remove contaminants attached to the porous surface and openings of the hydrophilic thin film 3, such as organic substances such as wax or NOX in the atmosphere (photocatalytic reaction). ). As a result, a decrease in hydrophilicity of the hydrophilic thin film 3 is prevented, and the antifogging property can be maintained for a long time.

The hydrophilic thin film 3 in FIG. 1 (b) is formed by dispersing (mixing) a photocatalytic reactant in a hydrophilic substance to form a porous film. As shown in the figure, a laminate in which a porous hydrophilic functional thin film 3b containing a hydrophilic substance is laminated on the surface side of a reactive thin film 3a containing a photocatalytic reactant may be used. The porous opening of the hydrophilic functional thin film 3b of this laminate is reactive It is more advantageous to reach the surface of the thin film 3a for the decomposition and removal of the organic matter by the electron-pair. However, even if the porous opening does not reach the surface of the reactive thin film 3a (that is, is closed on the way to the surface of the reactive thin film 3a), the electron-hole pair does not [Because it passes through the transparent hydrophilic functional thin film 3b, the photocatalytic reaction proceeds sufficiently, and organic matter can be decomposed and removed.

The hydrophilic thin film 3, the reactive thin film 3a, and the hydrophilic functional thin film 3b may be formed by physical vapor deposition (PVD) such as ion plating and sputtering, thermal CVD, and plasma CVD. It is preferable to carry out by a conventionally known thin film forming method such as a chemical vapor deposition (CVD) method such as VD. The thickness of each thin film is preferably 50 to 100 nm in the case of a single-layer hydrophilic thin film 3 in consideration of the hydrophilicity, photocatalytic reactivity, thin film strength and the like of the hydrophilic thin film 3. In the case of the hydrophilic thin film 3 of the laminate, the reactive thin film 3a preferably has a thickness of 50 to 100 nm, and the hydrophilic thin film 3b has a thickness of 5 to 100 nm.

(3) Conductive thin film

Electroconductive thin film 4, a transparent conductive material, _{_{e.g., ITO, I n 2 0 3}} , S N_〇 _{_2,} T a ₂ 0 ₅ or including a material which generates heat by energization, such as a mixture thereof. Further, since the conductive thin film 4 is provided on the back side of the transparent substrate member 2, water droplets (fogging) generated on the back side of the transparent substrate member can be removed, and the anti-fogging property is excellent. In particular, as shown in FIG. 1 (a), when the anti-fog element 1 is used for a camera hood 10 in which the temperature of the inside and outside air tends to be different (the transparent substrate member 2 tends to be fogged). It is advantageous. In the anti-fog element (camera hood glass) 1, the conductive thin film 4 is housed in the camera hood 10, so that the conductive thin film 4 is not exposed to the outside air. Therefore, the material constituting the conductive thin film 4 only needs to consider the above-described electrical conductivity (heat generation), and the durability due to exposure to the outside air, For example, there is no need to consider chemical resistance. As a result, the range of selection as a constituent material is expanded, the conductive thin film 4 can be formed with an inexpensive material, and the manufacturing cost of the anti-fog element 1 can be reduced. In addition, in combination with the hydrophilic thin film 3, usually, the hydrophilic thin film 3 prevents the front side of the transparent substrate member 2 from fogging, and only when the rear side of the transparent substrate member 2 becomes fogged, By causing the conductive thin film 4 to generate heat when energized to prevent fogging on the rear surface side, the amount of energization can be reduced, and the running cost of the anti-fogging element 1 can be reduced.

The conductive thin film 4 is preferably formed by a PVD method, a CVD method, a printing method, a coating method, or the like, similar to the method for forming the hydrophilic thin film 3. The thickness of the conductive thin film 4 is preferably 10 to 100 nm in consideration of heat generation, thin film strength, reflection characteristics and the like. Although not shown, the conductive thin film 4 is connected to an electrode (electrode film) for conducting electricity.

(4) Anti-reflective thin film (single layer)

Antireflection film 5, the transparent low refractive index material, for _{example, S i 0 2, A 1} 2 0 3, C e F 3, L a F 3, B a F 2, C a F 2, L i F, N including _{_{a 3 a l F 6, N}} a F, M g F 2, a 1 2 0 3 and Z r 0 mixture of ₂ or the like is also a combination of these. By providing the anti-reflection thin film 5, the reflection at the conductive thin film 4 of (3) can be suppressed. The method for forming the anti-reflection thin film 5 is preferably performed by the same PVD method, CVD method, or the like as the hydrophilic thin film 3. The thickness of the antireflection thin film 5 is preferably 50 to 150 nm in consideration of antireflection characteristics, light interference suppression characteristics, and the like. If it is less than 50 nm, the effect of preventing reflection and the effect of suppressing light interference are small, and light transmitted through the anti-fog element tends to have an interference color. In addition, the strength of the thin film is small and it is easy to be ruptured, and the film thickness is too thin to control the film formation. If the thickness exceeds 15 O nm, the antireflection effect tends to decrease, and the conductive thin film 4 Reflection is not suppressed, and the reflection image of the conductive thin film 4 easily appears in the image transmitted through the anti-fog element 1.

FIGS. 3 to 5 show spectral transmittance characteristics of the anti-fog element. In the figure, (A) is a spectral transmittance characteristic diagram of the anti-fogging element having no anti-reflection thin film, and (B 1) to (B 6) are anti-fogging elements of the present invention having an anti-reflection thin film (single layer). FIG. 4 is a spectral transmittance characteristic diagram of FIG.

FIG. 3 shows an example in which a SiO ₂ film (Si i _{2 has} a refractive index of 1.46) is used as an anti-reflection thin film (single layer).

(A) S i 0 ₂ / T i 〇 ₂ Z glass / ITO

Transparent glass 1. 9 mm (hereinafter, simply referred to as a transparent glass.) T i 〇 on the surface of ₂ film 2 0 0 nm, are sequentially deposited S i 〇 ₂ film 2 0 nm, ITO on the back surface of the transparent glass An anti-fog element with a thickness of 200 nm. Incidentally, the refractive index, S i O ₂ force SI. 4 6, T i 0 ₂ is 2.3 5, glass is 1. 5 2, ITO 2. 0 6.

_{(B 1) S i 0 2} / T i 〇 ₂ / Glass _{/ ITO / S i 0 2 5} 0 nm

T i 0 ₂ film 2 0 0 nm on a surface of a transparent glass, sequentially deposited S i 0 ₂ film 2 0 nm, ITO film 2 0 0 nm on the back surface of the transparent glass, the S i 〇 ₂ film 5 0 nm Antifogging elements formed sequentially.

_{(B 2) S i 0 2} / T i 0 2 / Glass / ITO / S i 〇 ₂ 1 5 0 nm T i on the surface of the transparent glass 0 ₂ film 2 0 0 nm, the S i 〇 ₂ film 2 0 nm sequentially deposited, ITO layer 2 0 O nm on the back surface of the transparent glass, S i 0 ₂ film 1 5 0 nm sequentially deposited anti-fog element.

FIG. 4 shows an example in which a MgF ₂ film (the refractive index of MgF ₂ is 1.38) is used as an anti-reflection thin film (single layer).

(A) S i 0 ₂ / T i 〇 ₂ / glass / ITO

Antifogging element having the same configuration as (A) in Fig. 3. _{(B 3) S i 0 2} ZT i 0 2 / Garasuno _{ITO / M g F 2 5 T} i 0 on the surface of the 0 nm transparent glass ₂ film 2 0 0 nm, S i 0 2 film sequentially formed 2 0 nm and, ITO film 2 0 0 nm on the back surface of the transparent glass, M g F ₂ film 5 0 nm sequentially deposited anti-fog element.

(B 4) S i 0 ₂ T i 〇 ₂ Z glass / ITO / M g F ₂ l 50 nm T i 〇 ₂ film 200 nm, S i 〇 ₂ film 20 nm on transparent glass surface sequentially deposited, ITO layer 2 0 0 nm on the back surface of the transparent glass, M g F ₂ film 1 5 0 eta sequentially deposited anti-fog element m.

Figure 5 is a anti-reflection film (single layer) A 1 ₂ 0 ₃ film (refractive index of A l ₂ 〇 ₃ 1.6 7) is an example of using,

(A) S i 0 ₂ / T i O ₂ / glass Ϊ TO

Antifogging element having the same configuration as (A) in Fig. 3.

(B 5) S i 0 ₂ ZT i 0 ₂ / Glass ITO / A 1 ₂ ₃ 0 0 5 0 nm A Ti 0 ₂ film 200 nm and a S i 〇 ₂ film 20 nm are sequentially formed on the surface of the transparent glass. film, ITO film 2 0 0 n on the underside of a transparent glass, im, a 1 ₂ 0 ₃ film 5 0 nm sequentially deposited anti-fog element.

_{(B 6) S i 0 2} ZT i 0 2 Z glass _{_{/ ITO / A 1 2 0 3}} 1 5 0 nm T i on the surface of the transparent glass 0 ₂ film 2 0 0 nm, the S i 0 ₂ film 2 0 nm sequentially deposited, ITO layer 2 0 0 nm on the back surface of the transparent glass, a 1 ₂ 0 ₃ film 1 5 0 eta sequentially deposited anti-fog element m.

As shown in FIGS. 3 to 5, it was found that the presence of the anti-reflection thin film increased the transmittance in the visible light region, and prevented reflection on the conductive thin film (B 1 to B6). Next, a second embodiment of the present invention is shown in FIG. 2 (a). As shown in FIG. 2 (a), the anti-fog element 1 is composed of a transparent substrate member 2 and a hydrophilic thin film. 3, a conductive thin film 4, and an anti-reflection thin film 5, and a first intermediate thin film 6 provided between the transparent substrate member 2 and the hydrophilic thin film 3. Hereinafter, each configuration will be described in detail. The transparent substrate member 2, the hydrophilic thin film 3, the conductive thin film 4, and the anti-reflection thin film 5 have the same configurations as in the above (1) to (4), and thus the description is omitted.

(5) First intermediate thin film

The refractive index of the first intermediate thin film 6 has an intermediate value between the refractive index of the hydrophilic thin film 3 and the refractive index of the transparent substrate member 2. Then, its refractive index is smaller than the refractive index of the hydrophilic thin film 3, and larger structure is preferably made than the refractive index of the transparent substrate member 2, for _{_{example, ITO, I n 2 0 3}} , S n 0 _{_{2, Z n O, W0 3}} , T a 2 0 5, Z r 〇 inorganic oxides such as _2, composite inorganic oxides such as a mixture of a 1 ₂ 0 ₃ and L a, or transparency of a combination of these Including. By providing the first intermediate thin film 6, it is possible to suppress the reflection at the hydrophilic thin film 3 of the above (2). This first intermediate thin film 6 is preferably formed by a PVD method, a CVD method, or the like, similar to the method for forming the hydrophilic thin film 3. Further, the first intermediate thin film 6 is formed by laminating a plurality of thin films containing the above-mentioned inorganic oxide, composite inorganic oxide, or a combination thereof. The refractive index of the hydrophilic thin film 3 and the transparent substrate 2 It may have a refractive index between the above and a single-layer thin film.

The thickness of the first intermediate thin film 6 is preferably 5 to 200 nm in consideration of antireflection characteristics, light interference suppression characteristics, and the like. If it is less than 5 nm, the effect of preventing reflection and the effect of suppressing light interference are small, and light transmitted through the anti-fog element tends to have an interference color. In addition, the film thickness is too thin, and it is easy to control the film formation. If it exceeds 200 nm, the antireflection effect tends to be small, the reflection on the hydrophilic thin film 3 is not suppressed, and the reflection image of the hydrophilic thin film 3 is easily reflected on the image transmitted through the anti-fog element 1. FIG. 2 (b) shows a third embodiment of the present invention. As shown in FIG. 2 (b), the anti-fogging element 1 includes a transparent substrate member 2, a hydrophilic thin film 3, a conductive thin film 4, and an anti-reflective thin film 5a. It has a laminated structure where two or more thin films are laminated (a thin film 51 and a thin film 52 in FIG. 2 (b)). Hereinafter, each configuration will be described in detail. Note that the transparent substrate member 2, the hydrophilic thin film 3, and the conductive thin film 4 have the same configurations as in the above (1) to (3), and thus description thereof will be omitted.

(6) Anti-reflective thin film (laminated)

The anti-reflection thin film 5a is formed by laminating two or more transparent thin films containing substances having different refractive indexes. For example, the thin film 52 is formed of a low-refractive index substance, for example, S i 0 ₂ , A 1 ₂ 〇 ₃ , C e F or L a F or B a F ₂ヽ C a F ₂ , L i F, N a ₃ A l F ₆ , N a F, M g F ₂ , A 1 ₂ 0 ₃ and Z r 0 mixture of ₂ or consists like a combination of these, a thin film 5 1, sea urchin by which the refractive index is larger than the refractive index of the thin film 5 2, for _{example, T i O 2, Z r} O ₂ , Ta ₂ 〇 ₅ etc. Then, the refractive index of the entire antireflection thin film 5 a is set to be smaller than the refractive index of the conductive thin film 4. By providing the antireflection film 5a (thin films 51, 52), reflection at the conductive thin film 4 of (3) can be suppressed. This anti-reflection thin film 5a is preferably formed by the same PVD method, C VD method or the like as in the case of the hydrophilic thin film 3. The thickness of the antireflection thin film 5a (thin film 51, 52) is appropriately set in consideration of antireflection characteristics and the like.

6 to 9 show spectral transmittance characteristics of the anti-fog element. In the figure, (A) is a spectral transmittance characteristic diagram of the antifogging element having no antireflection thin film (lamination), and (B7;) to (B10) are the present invention having an antireflection thin film (lamination). FIG. 5 is a spectral transmittance characteristic diagram of the anti-fog element of FIG. Figure 6 is an example using the T i 〇 ₂ film and the S i 〇 ₂ film as an antireflection film (laminate),

_{(A) S i 0 2 /} T i 0 2 / Glass / ITO

Antifogging element having the same configuration as (A) in Fig. 3.

(B 7) S i 0 ₂ / T i 0 ₂ Z glass / ITO / two layers (T i O no S i 0 ₂

)

T i 0 ₂ film 2 0 0 nm on a surface of a transparent glass, S i 0 ₂ film 2 0 nm are sequentially deposited, ITO layer 2 0 O nm on the back surface of the transparent glass, T i 0 ₂ film 2 5 nm, S i 0 ₂ film 4 5 nm, T i 〇 ₂ film 2 7 0 nm, 3 1 〇 ₂ film 1 3 0 11 111 sequentially deposited anti-fog element.

Figure 7 is an example of using the Z r 〇 ₂ film and the S i 〇 ₂ film as an antireflection film (laminate),

(A) S i 0 ₂ / T i O ₂ Z glass / ITO

Antifogging element having the same configuration as (A) in Fig. 3.

(B 8) S i O ₂ / T i 0 ₂ Glass 1 TO / S i 〇 ₂ 2 layers (Z r O ₂

/ sio ₂ )

T i 0 ₂ film 2 0 O nm on the surface of the transparent glass, S i 〇 ₂ film 2 are sequentially deposited 0 nm, ITO film 2 0 0 nm on the back surface of the transparent glass, S i 〇 ₂ film 4 5 nm, Z r 〇 ₂ film 2 5 nm, S i 〇 ₂ film 4 5 nm, Z R_〇 ₂ film 2 7 0 nm, S i 0 2 film 1 3 0 nm sequentially deposited anti-fog element.

Figure 8 is an example of using the T a ₂ 0 ₅ film and S i 〇 ₂ film as an antireflection film (laminate),

_{(A) S i 0 2 /} T i 0 2 / Glass / ITO

Antifogging element having the same configuration as (A) in Fig. 3.

(B 9) S i 0 ₂ ZT i 0 ₂ Z glass / ITO / 3 layer (T a ₂₀ o S i 0 ₂

) T i 0 ₂ film 2 0 0 nm on a surface of a transparent glass, S i 0 ₂ film 2 are sequentially deposited 0 nm, ITO film 2 0 0 nm on the back surface of the transparent glass, T a ₂ 0 ₅ film 2 5 nm , S i 〇 ₂ film _{2 5 nm, T a 2 0} 5 film 1 6 0 nm, S i 〇 ₂ film _{3 0 nm, T a 2 0} 5 film 1 2 0 nm, S i 0 2 film 1 3 0 nm , Anti-fog element ₀

Figure 9 is an example of using the T a ₂ 0 ₅ film and M g F ₂ film as an antireflection film (laminate),

(A) S i 0 ₂ / T i 〇 ₂ / glass / ITO

Antifogging element having the same configuration as (A) in Fig. 3. .

(B1 0) S i Ο, / Ύ i 0 ₂ / glass ZITO / T a, O _s / M g F ₂ T i 0 ₂ film 200 nm, S i 0 ₂ film 20 on transparent glass surface nm are sequentially deposited, ITO layer 2 0 0 nm on the back surface of the transparent glass, T a ₂ 〇 ₅ film 2 7 0 η m, M g F 2 film 1 3 0 nm sequentially deposited anti-fog element.

As shown in FIGS. 6 to 9, it was found that the presence of the anti-reflection thin film (lamination) increased the transmittance in the visible light region, and prevented reflection in the conductive thin film. (See B7-: B10). FIG. 2 (c) shows a fourth embodiment of the present invention. As shown in FIG. 2 (c), the anti-fogging element 1 has a transparent substrate member 2, a hydrophilic thin film 3, and a conductive thin film 4, and has a structure between the transparent substrate member 2 and the conductive thin film 4. It has a second intermediate thin film 7 provided on the substrate. Hereinafter, each configuration will be described in detail. Note that the transparent substrate member 2, the hydrophilic thin film 3, and the conductive thin film 4 have the same configurations as in the above (1) to (3), and thus description thereof will be omitted.

(7) Second intermediate thin film

The refractive index of the second intermediate thin film 7 has an intermediate value between the refractive index of the transparent substrate member 2 and the refractive index of the conductive thin film 4. And the refractive index of the transparent substrate member Greater than 2 of the refractive index, and is preferably is also smaller configuration Ri by the refractive index of the conductive thin film 4, for _{_{example, A 1 2 0 3, WO}} M g inorganic oxides such as O, A 1 ₂ 0 Includes composite inorganic oxides such as a mixture of ₃ and La, or transparent materials combining these. By providing the second intermediate thin film 7, the reflection at the conductive thin film 4 of (3) can be suppressed. This second intermediate thin film 7 is preferably formed by a PVD method, a CVD method, or the like, similar to the method for forming the hydrophilic thin film 3. The second intermediate thin film 7 is formed by laminating a plurality of thin films containing the above-described inorganic oxide, composite inorganic oxide, or a combination thereof, and the refractive index of the transparent substrate member 2 and the conductive thin film 4 It may have a refractive index intermediate between the refractive index of the film and a single-layer thin film.

The thickness of the second intermediate thin film 7 is preferably 5 to 200 nm in consideration of the antireflection effect. If the film thickness is outside the above range, the effect of suppressing reflection at the conductive thin film 4 tends to be small, and the reflection image of the conductive thin film 4 tends to be reflected on the image transmitted through the anti-fog element 1.

FIG. 10 shows a spectral transmittance characteristic diagram of the anti-fog element. In the figure, (A) is a spectral transmittance characteristic diagram of the anti-fogging element without the second intermediate thin film, and (B 11) is a spectral transmittance characteristic diagram of the anti-fogging element of the present invention having the second intermediate thin film. It is. The first 0 figure as the second intermediate thin an example using A 1 ₂ 〇 ₃ _{film, (A) S i 0 2} ZT i 0 2 glass / I TO

Antifogging element having the same configuration as (A) in Fig. 3.

(B 1 1) S i ο ₂ / τ i 〇 ₂ Z glass ZA 1 ₂ o ₃ ZITO

T i 0 ₂ film 2 0 0 nm on a surface of a transparent glass, S i 0 ₂ film successively deposited 2 0 nm, A 1 ₂ 0 ₃ film 5 O nm on the back surface of the transparent glass, 1 chome 〇 film 2 0 An antifogging element in which 0 11 111 is sequentially formed. The refractive index, S i 0 ₂ is 1. 4 6, T i O 2 is 2.3 5, glass _{1. 5 2, A 1 2 0} 3 force 1. 6 7, ITO is 2.0 6 It is. As shown in FIG. 10, it was found that the presence of the second intermediate thin film increased the transmittance in the visible light region and prevented reflection on the conductive thin film (see B11). ). The present invention is not limited to the first to fourth embodiments. For example, a configuration in which a second intermediate thin film 7 is added to the second embodiment (FIG. 2A), a third embodiment (FIG. 2 (b)) in which at least one of first intermediate thin film 6 and second intermediate thin film 7 is added. First intermediate thin film 6 is added in the fourth embodiment (FIG. 2 (c)). The configuration may be as follows. Industrial applicability

According to the first aspect, the hydrophilic thin film evaporates water droplets adhered to the surface side of the transparent substrate member, thereby preventing clouding. Further, the photocatalytic reaction substance of the hydrophilic thin film does not decrease the hydrophilicity of the hydrophilic thin film, and maintains the anti-fogging property. In addition, the conductive thin film prevents water droplets adhering to the back surface of the transparent substrate member from evaporating, thereby preventing fogging. As a result, the present invention can be applied to an anti-fog element typified by a hood glass for a camera which requires excellent anti-fog properties. In addition, the anti-reflection thin film suppresses reflection at the conductive thin film caused by a difference in refractive index, and prevents a reflected image of the conductive thin film from being reflected on an image transmitted through the anti-fog element, thereby providing a good image. It can be applied to anti-fog elements such as required camera hood glass. Furthermore, since there is no need to consider the durability of the conductive thin film and anti-reflective thin film, there are no restrictions on the constituent materials, and the anti-fog element represented by camera hood glass, which requires low cost, is required. Can be applied. Further, according to the second invention, the difference in the refractive index can be reduced by the first intermediate thin film. Reflection of the hydrophilic thin film that occurs is suppressed, and the reflected image of the hydrophilic thin film does not appear in the image transmitted through the anti-fog element, and a good image is required. It can be applied to devices. According to the third aspect of the present invention, the laminated structure of the anti-reflection thin film enhances the anti-reflection effect in the visible ray region, and the image transmitted through the anti-fog element becomes closer to the real image. As a result, the present invention can be applied to an anti-fog element typified by a camera hood glass requiring a good image. According to the fourth aspect, the reflection of the conductive thin film caused by the difference in the refractive index is suppressed by the second intermediate thin film, and the reflected image of the conductive thin film is displayed on the image transmitted through the anti-fog element. This can be applied to an anti-fog element typified by a hood glass for a camera that requires no good image.

Claims

The scope of the claims

1. A transparent substrate member,

A transparent hydrophilic thin film provided on the surface side of the transparent substrate member and containing a photocatalytic reactant and a hydrophilic substance;

A transparent conductive thin film provided on the back side of the transparent substrate member and containing a conductive substance;

An anti-fog element comprising: a transparent anti-reflection thin film further provided on the back side of the conductive thin film and containing a low refractive index substance.

2. A transparent first intermediate thin film is provided between the transparent substrate member and the hydrophilic thin film, and the refractive index of the first intermediate thin film is determined by the refractive index of the hydrophilic thin film and the refractive index of the transparent substrate member. The anti-fogging element according to claim 1, wherein the anti-fogging element has an intermediate value of the following.

3. The anti-fogging element according to claim 1, wherein the anti-reflection thin film has a laminated structure in which two or more thin films are laminated.

4. A transparent substrate member,

A transparent second intermediate thin film provided on the back side of the transparent substrate member, and a transparent conductive thin film further provided on the back side of the second intermediate thin film and containing a conductive substance,

The anti-fogging element, wherein a refractive index of the second intermediate thin film has an intermediate value between a refractive index of the transparent substrate member and a refractive index of the conductive thin film.