JPH1045435A - Low-reflection glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a low-reflection glass having an excellent surface low- reflection function and self-cleaning function capable of maintaining both functions for a long time and capable of keeping the low-reflection by making a soil such as finger mark and sweat always inconspicuous. SOLUTION: A thin film layer having a refractive index (n1 ) of 1.78-2.30 and a film thickness (d1 ) of 20-120nm is formed on at least one side surface of a transparent glass substrate as the first layer on the side of the glass, then the thin film layer having the refractive index (n2 ) of 1.46-1.90 and the film thickness (d2 ) of 40-120nm and dispersed with TiO2 fine particles having an optically active function is laminated on the first thin film layer as the second layer, and the refractive indexes satisfy (n1 )>(n2 ).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has both a function of reducing surface reflection and a function of self-cleaning. For example, self-cleaning of fingerprints, oils and other contaminants, sweat and other dirt, etc. adhering to the surface in the presence of ultraviolet rays. By eliminating
The present invention relates to a low-reflection glass capable of maintaining a surface reflection reducing function for a long time, maintaining excellent visibility and eliminating false recognition, and contributing to improvement in security and safety.

The low-reflection glass of the present invention is used as a window glass for buildings, vehicles, ships or aircraft, a touch panel for various electronic and electric devices such as a CD machine, a glass for cooking utensils, and various showcases for exhibitions. This is a useful material that can be used in a wide range of fields, such as glass, cover glass, and various display screens.

[0003]

2. Description of the Related Art Conventionally, various low-reflection glasses and glasses belonging to the category have been proposed and adopted in various fields. On the other hand, for example, in the case of interference-type low-reflection glass and the like, the film of the glass is used. Dirt such as fingerprints, sweat, hand stains, and oils and fats on the surface degrades the optical design, making low-reflection characteristics difficult to function. Conversely, the reflectivity increases and the surface becomes a low-reflection glass. Since it is no longer possible to achieve the desired purpose, various proposals have been made to prevent this, especially for touch panels and the like.

[0004] For example, Japanese Patent Application Laid-Open No. 60-49079 discloses an antifingerprint agent, which contains a compound containing a polyfluoroalkyl group or a polyfluoroether group having 4 to 21 carbon atoms. Have been.

For example, the structure of a touch panel is described in a microfilm of Japanese Utility Model Application No. 59-143325 (Japanese Utility Model Application Laid-Open No. 61-57423), and it is described that fine irregularities are provided on the surface of the touch panel body. Have been.

For example, a transparent touch panel is described in a microfilm of Japanese Utility Model Application No. 60-152692 (Japanese Utility Model Application Laid-Open No. 62-59922), and a membrane system in which substrates having electrodes formed on the surface thereof are opposed to each other. It discloses that a transparent abrasion-resistant fluorine-based resin is applied to the outer surface of a transparent substrate serving as a touch surface of a transparent touch panel.

For example, a microfilm (Japanese Utility Model Application Laid-Open No. 3-96639) of Japanese Utility Model Application No. Hei 2-5072 describes a screen for a projection type display device and a projection type display device using the same. It is described that a low reflection layer is provided on at least the observer side of the element.

For example, Japanese Patent Application Laid-Open No. 4-171521 discloses a touch panel, in which a transparent conductive film on a transparent substrate is covered with a composite transparent protective film in which an organic film is stacked on an inorganic film, and the organic film is It is described that it is the outermost layer, and that the organic film is a fluororesin film, an organic ultrafine particle film, or an organic hard coat film.

[0009] For example, Japanese Patent Application Laid-Open No. 6-110049 discloses a liquid crystal display device having an oil-repellent film, which describes that a substrate is provided with a protective film chemically bonded through a siloxane bond. Have been.

[0010] For example, Japanese Patent Application Laid-Open No. Hei 7-116623 describes a method of removing an oil film from an antireflection layer. An adhesive layer is press-bonded to an oil film adhering as a fingerprint or the like to the surface of the antireflection layer. It is described that the adhesive layer is peeled off while transferring an oil film.

On the other hand, for example, JP-A-64-70701 discloses a transparent plate having a conductive anti-reflection film, and has a refractive index of 1.90 to 2.50 and a film thickness on a metal film for imparting conductivity. 20
A film comprising a high-refractive-index dielectric film having a refractive index of 0 ° to 400 ° and a low-refractive-index dielectric film having a refractive index of 1.35 to 1.50 and a film thickness of 700 ° to 1200 ° on its surface is disclosed.

[0012] On the other hand, TiO ₂ , V ₂ O ₅ , ZnO, WO ₃ , Fe ₂ O _{3, and the} like are substances that exhibit a function of promoting the decomposition (oxidation) of stains on organic compounds when irradiated with ultraviolet rays. In particular, it is known that anatase-type crystal TiO ₂ fine particles have an excellent effect as a photocatalyst. Recently, for example, Japanese Patent Application Laid-Open No. 7-232080 discloses a multifunctional material having a photocatalytic function and a method for producing the same.

[0013]

For example, the aforementioned anti-fingerprint agent disclosed in JP-A-60-49079 is disclosed in
The transparent touch panel described in the microfilm of No. 52692 (Japanese Utility Model Application Laid-Open No. 62-59922), the screen for the projection display device described in the microfilm of Japanese Utility Model Application No. 2-5072 (Japanese Utility Model Application No. 3-96639), and Projection type display device using the same, JP-A-4-17
No. 1521 JP-A-6100
In the liquid crystal display device having an oil-repellent film described in Japanese Patent Publication No. 49, various kinds of dirt such as a fluororesin film, a protective film chemically bonded through a siloxane bond, a low-reflection layer or a silicon-based film layer are adhered. This is to provide an antifouling film to make it difficult.

In the structure of the touch panel described in the microfilm of Japanese Utility Model Application No. 59-143325 (Japanese Utility Model Application No. 61-57423), various dirts are similarly hardly adhered by forming a fine uneven surface. According to the method for removing an oil film from the antireflection layer described in JP-A-7-116623, an adhesive layer is forcibly pressed against an oil film such as a fingerprint on the surface of the antireflection layer, and the adhesive layer is adhered to the adhesive layer. It is intended to transfer the oil film and forcibly peel it off.

On the other hand, for example, the conductive anti-reflection film described in Japanese Patent Application Laid-Open No. 64-70701 is an interference type anti-reflection film. Therefore, if a film such as sweat or dirt is formed on the film surface, an optical design is required. Not only does the anti-reflective property disappear, but also the reflectance increases and the film becomes highly reflective, and the color tone changes and becomes noticeable only in the film part such as sweat and dirt on the film surface, and therefore, Frequent cleaning such as cleaning is required. In order to prevent these stains, it is not sufficient to apply only an antifouling film which makes these various stains difficult to adhere, and a self-cleaning function is provided so that the stains are not always noticeable while reducing reflection. They had to be combined.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and is directed to a two-layer antireflection thin film formed on at least one surface of a transparent glass substrate, preferably on both front and back surfaces. Using a thin film in which TiO ₂ fine particles having a photoactive effect are dispersed in the outermost thin film of the laminated thin film,
By providing a self-cleaning function, adjusting the thickness and the refractive index of each layer by appropriately combining and specifying them, and appropriately reducing the reflectance, the reflection is excellently reduced, and the visibility is high. Another object of the present invention is to provide a useful low-reflection glass having a self-cleaning function for making dirt always inconspicuous in the presence of ultraviolet rays, in addition to obtaining a low-reflection glass in addition to providing high comfort and comfort.

That is, the present invention provides a thin film layer having a refractive index n ₁ of 1.78 to 2.30 and a thickness d ₁ of 20 to 120 nm as a first layer from the glass surface side on at least one surface of a transparent glass substrate. Is formed, and then a second layer is formed on the first thin film layer.
The refractive index n ₂ as a layer th a 1.46 to 1.90 and the thickness d ₂
A low-reflection glass, which is formed by coating and laminating a thin film layer in which TiO ₂ fine particles having a photoactive action and having a wavelength of 40 to 120 nm are dispersed, and wherein the refractive index is n ₁ > n ₂ .

Further, the first thin film is made of SiO ₂ ,
The low-reflection glass described above, which is a composite film of TiO ₂ , Al ₂ O ₃ , ZrO ₂ , SnO ₂ , B ₂ O ₃ and a combination of two or more thereof.

The second layer has a photoactive effect.
Thin film with TiO ₂ fine particles dispersed, SiO ₂ , Al ₂ O ₃ , ZrO ₂ ,
The low reflection glass described above, which is a composite film comprising SnO ₂ and a combination thereof.

Further, the TiO ₂ fine particles having a photoactive effect are anatase type and have an average particle diameter of 3 nm or more and 50 nm or less.
The object of the present invention is to provide the above-described low reflection glass characterized by the following.

[0021]

DETAILED DESCRIPTION OF THE INVENTION Here, a refractive index n ₁ is 1.78 to 2.30 and 20 to the thickness d ₁ as the first layer from the glass surface side
Forming a thin film layer of 120 nm, then the first layer of the thin film layer, the refractive index n ₂ as the second layer is a 1.46 to 1.90 and the thickness d ₂ is 40~120nm and photoactive TiO ₂ with action
It comprises a thin film layer in which fine particles are dispersed by coating stack, yet the said refractive index was that made by a n _1> n ₂ is
For example, when a high refractive index thin film having a refractive index of more than 2.3 is used, and as the thin film layer becomes more than two layers and becomes a multilayer thin film layer, the reflection becomes stronger due to multiple interference, and the visible light transmittance becomes 70% or more. Alternatively, this is because the reflection reduction is unlikely to be the expected value. If the refractive index and the film thickness of the first and second thin films are not within the values, for example, the visible light reflectance becomes 3% or more. This is because the glass cannot be said to be a glass whose reflection has been reduced at all.

The first layer has a refractive index n ₁ of 1.78 to 2.
The reason for setting the value to 30 is that it is difficult to form an oxide thin film exceeding 2.30 by the Solkel method, and if it is less than 1.78, the visible light reflectance becomes 3% or more and it cannot be said that the reflection is low.

The refractive index n ₂ of the second layer is set to 1.46 to 1.
The reason for setting the value to 90 is that if it exceeds 1.90, the visible light reflectance becomes 3% or more and it cannot be said that the reflection is low, and the higher the content of the photoactive TiO ₂ fine particles, the lower the film strength becomes. This is because the TiO ₂ fine particles can hardly be dispersed and the self-cleaning function cannot be exhibited.

The reason that the refractive index satisfies n ₁ > n ₂ is that low reflection does not occur when n ₁ <n ₂ . Furthermore, for example, the refractive index n ₁ of the first layer is 1.78 to 2.30
In, the refractive index n ₂ of the second layer is from 1.46 to 1.90, the first
As the thin film layer, TiO ₂ : SiO ₂ = 40: 60 to 10 in molar ratio
It is preferable to combine a thin film having 0: 0 and a thin film having a molar ratio of photoactive TiO ₂ fine particles: SiO ₂ = 1: 99 to 50:50 as the second thin film layer. Even more preferably, a refractive index n ₁ of the first layer is 1.90 to 2.10, if the second layer having a refractive index n ₂ is from 1.54 to 1.70, as the first layer thin film layer, TiO molar ratio ₂ : A thin film in which SiO ₂ = 50: 50 to 85:15 and a thin film in which the molar ratio of photoactive TiO ₂ fine particles: SiO ₂ = 10: 90 to 30:70 are used as the second thin film layer. By combining them, a good low reflection performance and a good self-cleaning function can be obtained.

Further, the thin film of the first thin film layer is made of Si
It is preferable to use a composite film of O ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , SnO ₂ , B ₂ O ₃ and a combination of two or more selected from them. TiO ₂ (about 2.25), ZrO ₂ (about 1.95), SnO ₂ (about 1.9), SiO ₂ (about 1.45) with a relatively low refractive index, Al ₂ O
₃ (about 1.65), or B ₂ O ₃ (about 1.60) and by mixing various combinations of freely refractive index n ₁ and the control tends to give a composite film such that from 1.78 to 2.30, and durable It is because it becomes what is excellent in nature.

Further, the thin film of the second thin film layer is made of Si
O ₂ (approximately 1.45) and Al ₂ O ₃ (approximately 1.65) alone, of course, a composite film combining these SiO ₂ and Al ₂ O ₃ , ZrO ₂ and SnO ₂ alone, or SiO ₂ and Al ₂ O ₃ to ZrO ₂
And a composite film in which SnO ₂ is combined in a molar ratio of, for example, about 10% or less. In addition, the reason why the molar ratio is set to about 10% or less is that the durability is improved at this level, but if it exceeds 10%, the refractive index increases and the low reflection performance is deteriorated, and the photoactive Ti
This is because reducing the amount of the O ₂ fine particles reduces the self-cleaning function, and it is difficult to improve the durability.

The TiO ₂ fine particles having a photoactive effect have an anatase type crystal structure and an average particle diameter of preferably 3 nm to 50 nm, more preferably 4 nm to 30 nm. Things. If the particle size exceeds 50 nm, for example, the dispersibility in a coating solution will be poor, and it will be difficult to obtain a uniform film, and the haze value of the film will be high, and the visibility will be deteriorated.

Further, as a TiO ₂ fine particle dispersion having a photoactive action, for example, Taynock M-6 [manufactured by Takagi Chemical Co., Ltd., having an average particle size of 5 nm and a TiO ₂ concentration of 6% aqueous solution],
Tynoc A-6 [manufactured by Taki Kagaku Co., Ltd., average particle size is 10 nm,
TiO ₂ concentration 6% aqueous solution), ST-K series (manufactured by Ishihara Sangyo Co., Ltd., having an average particle size of 20 nm, dispersed in a SiO ₂ binder) and the like. Is preferred.

The diluting solvent is not particularly limited, but may be ethanol, methanol, isopropanol, or the like.
Acetone or a mixed solvent thereof is preferred. Furthermore, the method for forming the two-layer thin film is not particularly limited, but includes dipping, spin coating, flexographic printing, roll coating, flow coating, spraying, and printing. Or various existing coating methods, such as a coating method already proposed by the present applicant, and a film forming method combining these methods.

Further, the glass substrate may be colorless or colored as long as it is a transparent glass, that is, for example, clear, blue, bronze, gray or green glass. Alternatively, it is more preferable to use a gold color, a green color, and especially a green color tone that can easily obtain heat ray / ultraviolet absorption performance. Needless to say, it can be used not only as a single plate, but also as a multilayer, laminated glass, tempered glass, glass with increased strength, bent glass, and the like. further,
It goes without saying that the glass substrate may be inorganic or organic.

Furthermore, the photoactive titania fine particles exhibit a photoactive effect due to ultraviolet rays, not only in a place where sunlight containing a large amount of ultraviolet rays directly flows, but also in a place where sunlight shines through glass or in a sunshine. In a wide range of places and conditions, such as places where light is indirectly hit by scattering, etc., or places exposed to fluorescent lights that generate a small amount of ultraviolet light even where sunlight is not directly or indirectly (indoors) This shows the effect.

As described above, the low-reflection glass of the present invention comprises a thin film having a medium refractive index n _{1 and} a thin film having a low refractive index n ₂ in which fine particles of TiO ₂ having photoactivity are dispersed. Excellent reduction in surface reflection by combining two layers of thin film coatings with a predetermined thickness d _{1 and} d ₂ and a thickness in a specific range so that the refractive index is appropriately n ₁ > n _2. It has both a function and a self-cleaning function.For example, fingerprints, contaminants such as oils and fats, sweat and other dirt, etc. adhering to the surface can be eliminated by self-cleaning in the presence of ultraviolet rays while always being inconspicuous. It can suppress the feeling of feeling, maintain excellent visibility, eliminate misunderstandings and discomfort, and is highly durable, friendly to people and the environment, and can maintain the surface reflection reduction function and self-cleaning function for a long time And secure It is a useful low-reflection glass that contributes to the improvement of safety and security, window glass for construction, vehicles, ships or aircraft, touch panels for various electronic and electrical devices such as CD machines, and glass for cooking utensils, Various showcases and cover glass for display, various display screens
Can be adopted in a wide range of fields such as

[0033]

The present invention will be described below in detail with reference to examples. However, the present invention is not limited to such an embodiment.

Example 1 Hydrolyzed tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] and hydrolyzed isopropyl titanate [Ti (OC ₃
H ₇ ) ₄ ] was mixed at a molar ratio of 48:52, and ethanol was added thereto to dilute the solute concentration to about 0.42 mol / l to prepare an alkoxide solution for the first layer thin film. A solution of about 100 mm x 100 mm and a plate thickness of about 3 mm was added to this prepared solution.
Dipped lime glass (float glass) plate, about 4mm
/ 30 sec / sec.
By heating at 0 ° C. for about 30 minutes, a first layer thin film composed of a SiO ₂ .TiO ₂ thin film was obtained. When the viscosity of the prepared solution was measured, it was approximately
It was 2.0 mPa · s (2.0 cP).

Next, an aqueous solution of titania (TiO ₂ ) fine particles dispersed therein [Tynoc M-6, manufactured by Taki Kagaku KK, average particle size 5n
m, TiO ₂ concentration 6%] was diluted with ethanol about 6 times and stirred at room temperature for about 1 hour. Next, hydrolyzed tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] was added to this solution so that the molar ratio of silica to titania was 88:12, and the solute concentration in ethanol was about 0.25 mol / l. And stirred at room temperature for about 10 minutes using a homogenizer to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was about 2.3 mPa · s (2.3 cP).

Subsequently, the glass plate with the first layer thin film is
After being immersed in the prepared solution and pulled up at a speed of about 4 mm / sec, it was heated at about 300 ° C. for about 30 minutes to obtain a second layer thin film composed of the SiO ₂ thin film in which the TiO ₂ fine particles were dispersed.

This was fired at about 650 ° C. for about 10 minutes to obtain a low reflection glass. The refractive index and the film thickness of the first layer thin film and the second layer thin film in the obtained low reflection glass were measured with an ellipsometer [manufactured by Mizojiri Optical Co., Ltd.].
Refractive index n ₁ of the layer thin film is 1.95, the thickness d ₁ of about 77 nm, the refractive index n ₂ of the second thin film layer is 1.58, the thickness d ₂ was about 80 nm. The visible light transmittance of the low reflection glass is about 97%, and the wavelength is 550 n.
The reflectivity at m was 0.11%.

Further, stearic acid was applied to the surface of the second layer thin film of the low reflection glass by a spin coater, and irradiated with 3 mW / cm ² ultraviolet light using a black light.
The haze value was about 10.2% at the beginning, but 4.2% after 4 hours.
After 7 hours, it decreased to about 0.2%.

The low-reflection glass sufficiently exhibited a self-cleaning function and a low-reflection function, and was the intended low-reflection glass. Example 2 In the same manner as in Example 1, [Si (OC ₂ H ₅ ) ₄ ] and [Ti (OC ₃ H ₇ ) ₄ ] were mixed at a molar ratio of 22:78, and this was mixed with a solute concentration. The mixture was diluted with ethanol to a concentration of about 0.40 mol / l to prepare an alkoxide solution for the first layer thin film. To this prepared solution, soda lime glass (float glass) similar to that of Example 1 was used.
Immersing the plate, coating after the glass both sides pulled up at a rate of about 4.2 mm / sec, heated at about 250 ° C. for about 30 minutes, SiO ₂ · Ti
A first layer thin film composed of an O ₂ thin film was obtained. When the viscosity of the prepared solution was measured, it was about 1.9 mPa · s (1.9 cP).

Next, in the same manner as in Example 1, the molar ratio of silica to titania was 82:18, and the solute concentration was about
The mixture was diluted to 0.20 mol / l and stirred at room temperature for about 10 minutes using a homogenizer to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was approximately
It was 2.0 mPa · s (2.0 cP).

Subsequently, the glass sheet with the first layer thin film was
After being immersed in the prepared solution and pulled up at a speed of about 4.5 mm / sec, it was heated at about 300 ° C. for about 30 minutes to obtain a second layer thin film composed of a SiO ₂ thin film in which the TiO ₂ fine particles were dispersed.

This was fired at about 650 ° C. for about 10 minutes to obtain a low reflection glass. The refractive index and the film thickness of the first layer thin film and the second layer thin film in the obtained low reflection glass were measured with an ellipsometer [manufactured by Mizojiri Optical Co., Ltd.].
Refractive index n ₁ of the layer thin film is 2.02, the thickness d ₁ of about 80 nm, the refractive index n ₂ of the second thin film layer is 1.64, the thickness d ₂ was about 77 nm. The visible light transmittance of the low reflection glass is about 95.9%, and the wavelength is 55%.
The reflectance at 0 nm was 0.06%.

Further, stearic acid was applied to the surface of the second layer thin film of the low-reflection glass by a spin coater, and irradiated with 3 mW / cm ² ultraviolet light using a black light.
The haze value was about 10.5% initially, but 4.0% after 4 hours.
After 7 hours, it decreased to about 0.2%.

As in the case of Example 1, the low-reflection glass sufficiently exhibited a self-cleaning function and a low-reflection function, and was the intended low-reflection glass. Example 3 As in Example 1, [Si (OC ₂ H ₅ ) ₄ ] and [Ti (OC ₃ H ₇ ) ₄ ] were mixed at a molar ratio of 17:83, and this was mixed with a solute concentration. The mixture was diluted with ethanol to about 0.48 mol / l to prepare an alkoxide solution for the first layer thin film. To this prepared solution, soda lime glass (float glass) similar to that of Example 1 was used.
The plate is immersed, pulled up at a speed of about 3.0 mm / sec, coated on both sides of the glass, and heated at about 300 ° C for about 30 minutes to form SiO ₂
A first layer thin film composed of an O ₂ thin film was obtained. When the viscosity of the prepared solution was measured, it was about 2.5 mPa · s (2.5 cP).

Next, a titania (TiO ₂ ) fine particle dispersed aqueous solution [Tynoc M-6, manufactured by Taki Kagaku Co., Ltd., average particle size 5 n
m, TiO ₂ concentration 6%] was diluted with ethanol about 6 times and stirred at room temperature for about 1 hour. The solution was then hydrolyzed [Si (OC ₂ H ₅ ) ₄ ] and Al (NO ₃ ) ₃ previously dissolved in ethanol.
9H ₂ O with a molar ratio of silica, alumina and titania of 51: 3
In addition to 1:18, the solute concentration was about 0.1 with ethanol.
After dilution to 24 mol / l, an alkoxide solution for a second layer thin film was prepared in the same manner as in Example 1. When the viscosity of the prepared solution was measured, it was about 2.8 mPa · s (2.8 cP).

Subsequently, the glass plate with the first layer thin film was
After being immersed in this preparation solution and pulled up at a speed of about 3.9 mm / sec, it is heated at about 300 ° C. for about 20 minutes to form a second layer thin film comprising an Al ₂ O ₃ .SiO ₂ thin film in which the TiO ₂ fine particles are dispersed. I got

This was fired at about 650 ° C. for about 3 minutes to obtain a low reflection glass. The refractive index and the film thickness of the first layer thin film and the second layer thin film in the obtained low reflection glass were measured with an ellipsometer [manufactured by Mizojiri Optical Co., Ltd.].
Refractive index n ₁ of the layer thin film is 2.09, the thickness d ₁ of about 75 nm, the refractive index n ₂ of the second thin film layer is 1.69, the thickness d ₂ was about 76 nm. The visible light transmittance of the low reflection glass is about 95.6%, and the wavelength is 55%.
The reflectance at 0 nm was 0.04%.

Further, stearic acid was applied to the surface of the second layer thin film of the low-reflection glass by a spin coater, and irradiated with 3 mW / cm ² ultraviolet light using a black light.
The haze value was about 10.3% at the beginning, but 3.8% after 4 hours
After 7 hours, it decreased to about 0.2%.

As in the case of Example 1, the low-reflection glass sufficiently exhibited a self-cleaning function and a low-reflection function, and was the intended low-reflection glass. Comparative Example 1 Hydrolyzed [Si (OC ₂ H ₅ ) ₄ ] and an alkoxide of Ti were mixed at a molar ratio of 58:42, and isopropyl alcohol was added thereto to give a solute concentration of about 0.40 mol. / L of an alkoxide solution for a first layer thin film was prepared. A soda lime glass (float glass) plate similar to that in Example 1 was immersed in this prepared solution, pulled up at a speed of about 4.0 mm / sec, coated on both surfaces of the glass, and then at about 300 ° C. for about 30 minutes. Heat and Si
A first layer thin film composed of an O ₂ · TiO ₂ thin film was obtained. When the viscosity of the prepared solution was measured, it was about 2.0 mPa · s (2.0 cP).

Next, the hydrolyzed [Si (OC ₂ H ₅ ) ₄ ] was diluted with isopropyl alcohol to a solute concentration of about 0.35 mol / l to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was about 2.3 mPa
s (2.3 cP).

Subsequently, the glass sheet with the first layer thin film was
After being immersed in this prepared solution and pulled up at a speed of about 4.0 mm / sec, it was heated at about 300 ° C. for about 20 minutes to obtain a second layer thin film composed of a SiO ₂ thin film.

This was fired at about 650 ° C. for about 3 minutes to obtain a low reflection glass. The refractive index and the film thickness of the first layer thin film and the second layer thin film in the obtained low reflection glass were determined in Example 1.
And the refractive index n ₁ of the first layer thin film was 1.7
9, the film thickness d ₁ of about 77 nm, the refractive index n ₂ of the second thin film layer is 1.45, the thickness d ₂ was about 95 nm. The visible light transmittance of the low reflection glass is about 98.0%, and the reflectance at a wavelength of 550 nm is 0.10%.
%Met.

Further, stearic acid was applied to the second layer thin film surface of the low reflection glass by a spin coater, and irradiated with 3 mW / cm ² ultraviolet light using a black light.
The haze value, which was initially about 10.2%, did not change even after 7 hours, and stearic acid was not decomposed.

The low-reflection glass did not have a self-cleaning function and was not an intended low-reflection glass. Comparative Example 2 Si alkoxide and Ti alkoxide were in a molar ratio of 48:52.
Then, ethanol was added thereto to prepare an alkoxide solution for the first layer thin film so that the solute concentration was about 0.55 mol / l. A soda lime glass (float glass) plate similar to that in Example 1 was immersed in this prepared solution, and the solution was prepared for about 6.
After pulling up at a speed of 0 mm / sec and coating both sides of the glass,
Heating was performed at about 300 ° C. for about 30 minutes to obtain a first layer thin film composed of a SiO ₂ .TiO ₂ thin film. When the viscosity of the prepared solution was measured, it was about 2.8 mPa · s (2.8 cP).

Next, in the same manner as in Example 1, the molar ratio of silica to titania was set to 82:18, and the solute concentration was reduced to about ethanol with ethanol.
The mixture was diluted to 0.25 mol / l and stirred at room temperature for about 10 minutes using a homogenizer to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was about 2.
It was 3 mPa · s (2.3 cP).

Subsequently, the glass plate with the first layer thin film was
After being immersed in this prepared solution and pulled up at a speed of about 4.0 mm / sec, it was heated at about 300 ° C. for about 20 minutes to obtain a second layer thin film composed of the SiO ₂ thin film in which the TiO ₂ fine particles were dispersed.

This was fired at about 650 ° C. for about 10 minutes to obtain a self-cleaning glass.該得was Serufukuri - where the first thin film layer and the refractive index and film thickness of the second thin film layer in the training glass was measured in the same manner as in Example 1, the refractive index n ₁ of the first thin film layer is 1.95, the thickness d ₁ is about 140 nm, the refractive index n ₂ of the second thin film layer is 1.58, the thickness d ₂ was about 80 nm. The self-cleaning glass has a visible light reflectance of 550 nm.
m was about 8%, and the reflectance was almost the same as ordinary glass, and it was hard to say that the intended low-reflection glass was aimed at.

Comparative Example 3 In the same manner as in Comparative Example 2, an alkoxide of Si and an alkoxide of Ti were mixed at a molar ratio of 48:52, and ethanol was added thereto, so that the solute concentration was about 0.40 mol / l. Thus, an alkoxide solution for the first layer thin film was prepared. In this preparation solution,
Similar Seo Example 1 - da-lime glass (flow - sharpened) plate was dipped, after coating on glass both sides pulled up at a rate of about 2.8 mm / sec, heated at about 300 ° C. for about 30 minutes, SiO ₂
A first layer thin film made of a TiO ₂ thin film was obtained. When the viscosity of the prepared solution was measured, it was about 2.0 mPa · s (2.0 cP).

Next, as in Example 1, the molar ratio of silica to titania was 82:18, and the solute concentration was about
The mixture was diluted to 0.45 mol / l and stirred at room temperature for about 10 minutes using a homogenizer to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was about 2.
It was 8 mPa · s (2.8 cP).

Subsequently, the glass sheet with the first layer thin film was
After being immersed in the prepared solution and pulled up at a speed of about 6.0 mm / sec, it was heated at about 300 ° C. for about 20 minutes to obtain a second layer thin film composed of the SiO ₂ thin film in which the TiO ₂ fine particles were dispersed.

This was fired at about 650 ° C. for about 10 minutes to obtain a self-cleaning glass.該得was Serufukuri - where the first thin film layer and the refractive index and film thickness of the second thin film layer in the training glass was measured in the same manner as in Example 1, the refractive index n ₁ of the first thin film layer is 1.95, the thickness d ₁ is about 60 nm, the refractive index n ₂ of the second thin film layer is 1.56, the thickness d ₂ was about 140 nm. The self-cleaning glass has a visible light reflectance of 550 nm.
It was about 16% in m 2, which was not the intended low-reflection glass but high-reflection glass.

Comparative Example 4 Ethanol was added to the alkoxide of Ti to reduce the solute concentration to about 0.3.
An alkoxide solution for the first layer thin film was prepared to have a concentration of 0 mol / l. A soda lime glass (float glass) plate similar to that in Example 1 was immersed in this prepared solution, pulled up at a speed of about 3.5 mm / sec, and coated on both sides of the glass.
For about 30 minutes to obtain a first layer thin film made of a TiO ₂ thin film. When the viscosity of the prepared solution was measured, it was approximately 1.8 mPa
s (1.8 cP).

Next, as in Example 1, the molar ratio of silica to titania was set to 48:52, and the solute concentration was reduced to about 50% with ethanol.
The mixture was diluted to 0.30 mol / l and stirred at room temperature for about 10 minutes using a homogenizer to prepare an alkoxide solution for the second layer thin film. When the viscosity of the prepared solution was measured, it was about 3.
It was 0 mPa · s (3.0 cP).

Subsequently, the glass plate with the first layer thin film was
After being immersed in this prepared solution and pulled up at a speed of about 3.0 mm / sec, it was heated at about 300 ° C. for about 20 minutes to obtain a second layer thin film composed of a SiO ₂ thin film in which the TiO ₂ fine particles were dispersed.

This was fired at about 650 ° C. for about 10 minutes to obtain a self-cleaning glass.該得was Serufukuri - where the first thin film layer and the refractive index and film thickness of the second thin film layer in the training glass was measured in the same manner as in Example 1, the refractive index n ₁ of the first thin film layer is 2.20, the thickness d ₁ is about 63 nm, the refractive index n ₂ of the second thin film layer is 1.95, the thickness d ₂ was about 70 nm. The self-cleaning glass has a visible light reflectance of 550 nm.
It was about 4.2%, which was hardly the expected low-reflection glass.

[0066]

As described in detail above, the present invention provides a transparent glass substrate having a medium refractive index thin film and a photoactive
A simple two-layer thin film coating and lamination in which the low refractive index thin film containing TiO ₂ fine particles is combined with the specified refractive index and film thickness so that the refractive index of the second layer becomes smaller than the refractive index of the first layer. By using a low-reflection glass consisting of, it can be easily obtained, has both excellent surface reflection reduction function and self-cleaning function, and has a fingerprint attached to the surface,
Dirt such as oils and fats and sweat are self-cleaned in the presence of ultraviolet rays to disassemble them inconspicuously, eliminating the need for frequent cleaning, maintaining excellent visibility and eliminating misperception and discomfort. It is highly durable, is friendly to both human and physical aspects and the environment, and has a long-lasting surface reflection reduction function and self-cleaning function, contributing to improved security and safety. Window glass for architectural, vehicle, ship or aircraft use, CD
Touch panels for various electronic and electrical equipment such as machines, glass for cooking utensils, various showcases and covers for exhibitions
The present invention can provide a low-reflection glass useful in a wide range of fields such as glass and various display screens.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G02B 1/10 G02B 1/10 Z

Claims (4)

[Claims] 1. A refractive index n1 of at _least 1.78 to 2.2 on a surface of at least one side of a transparent glass substrate as a first layer from the glass surface side.
A 30 and the film thickness d ₁ to form a thin layer of 20 to 120,
Next, on the first thin film layer, as a second layer, a refractive index
n ₂ is made by coating stack a thin film layer containing dispersed TiO ₂ fine particles and the thickness d ₂ be 1.46 to 1.90 has is and photoactive action is 40 to 120 nm, yet the refractive index n _1> n ₂ is a low reflection glass. 2. The method according to claim 1, wherein the first thin film is made of SiO ₂ , TiO ₂ , Al.
_2. A composite membrane comprising ₂ O ₃ , ZrO ₂ , SnO ₂ , B ₂ O _3, and a combination of two or more of these.
The low reflection glass as described. 3. TiO ₂ having a photoactive action of the second layer
SiO ₂ , Al ₂ O ₃ , ZrO ₂ , SnO ₂
3. The low reflection glass according to claim 1, wherein the low reflection glass is a composite film obtained by combining these. 4. The TiO ₂ fine particles having a photoactive effect,
The low-reflection glass according to any one of claims 1 to 3, wherein the glass is an anatase type and has an average particle diameter of 3 nm or more and 50 nm or less.