JP2002047032A - Substrate with photocatalyst membrane and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate with a photocatalyst membrane easily produced on a large scale which has excellent durability and decomposing ability of contaminated materials. SOLUTION: The method of producing a substrate with a photocatalyst membrane comprises the steps of spreading TiO2 microparticles (photoactive microparticles) 2 having anatase-type crystal structure and particle size of 5 to 10 nm by a spray-gun onto a glass substrate 1 to fix on the surface of the glass substrate 1, heat-treating and sputtering to form SiO2 membrane 3 (cover) covering the TiO2 microparticles 2 so that the TiO2 microparticles 2 and the SiO2 membrane 3 constitute a photocatalyst membrane 4 in which the ratio of TiO2/SiO2 is controlled to be within 20/80 to 70/30 on weight basis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate with a photocatalyst film and a method for producing the same, and more particularly, to a substrate with a photocatalyst film used for various glass articles such as window glass and lighting equipment, and the production of the substrate with a photocatalytic film. About the method.

[0002]

2. Description of the Related Art Conventionally, in a glass article such as a window glass or a lighting fixture, a photocatalytic film is applied on a glass substrate to decompose contaminants adhering to the surface of the photocatalyst. It prevents dirt from adhering to the surface of the article.

That is, this type of substrate with a photocatalytic film is
The contaminants adhering to the surface can be decomposed by the oxidizing action (photocatalytic reaction) of the photocatalyst, thereby exhibiting a so-called self-fouling property (self-cleaning function) to maintain the cleanliness of the substrate surface. Can be.

[0004] As the substrate with a photocatalytic film,
Using titanium dioxide fine particles (TiO ₂ fine particles) as a photoactive substance that causes a photocatalytic reaction, TiO ₂ —SiO ₂ ,
A photocatalyst in which a photocatalyst film made of a mixed material of TiO ₂ —SnO ₂ or TiO ₂ —Al ₂ O ₃ is formed on a glass substrate has already been proposed (Japanese Patent Application Laid-Open No. 11-9994).

In the prior art, a photocatalyst film made of the above-mentioned hybrid material (binary material) is formed on the surface of a glass substrate, and the photocatalyst film contains 10 wt% to 30 wt% of TiO ₂ fine particles. Have been.

In the prior art, for example, TiO _2-
When forming a photocatalytic film with a mixed material of SiO ₂ , a mixed solution of an alkoxytitanium compound and an alkoxysilane compound is prepared, and then TiO ₂ fine powder is dispersed and suspended in the mixed solution to form a suspension. The photocatalyst is manufactured by preparing, then immersing and applying a glass substrate to the suspension, and then performing a baking treatment.

[0007]

[SUMMARY OF THE INVENTION However, in the conventional art, for example, in the case of forming the photocatalytic film composite material of the TiO ₂ -SiO _2, in the photocatalyst film is TiO ₂ particles and the SiO ₂ are mixed Therefore, the TiO ₂ fine particles exist near the film surface or are exposed on the film surface, so that the film surface is easily damaged, and the TiO ₂ fine particles are easily peeled off from the film surface. There was a problem that it was inferior.

Further, in the above-mentioned prior art, the above-mentioned composite material is applied on a glass substrate by immersing a glass substrate in a suspension. There is a problem in that it is not suitable for manufacturing a relatively large glass article such as a window glass, even though it is suitable for manufacturing such a relatively small glass article.

The present invention has been made in view of the above problems, and has a photocatalytic film-coated substrate having good self-contamination resistance, excellent durability, and easy mass production. It is intended to provide a manufacturing method.

[0010]

The present inventors have conducted intensive studies to improve the mechanical strength of a photocatalyst film, and as a result, coating the photoactive fine particles with a metal oxide may damage the film surface. In addition, it has been found that the separation resistance can be improved, whereby a substrate with a photocatalytic film having excellent mechanical strength can be obtained, and the durability of the substrate with a photocatalytic film can be dramatically improved. Was.

[0011] The present invention has been made based on such knowledge, and the substrate with a photocatalytic film according to the present invention is characterized in that photoactive fine particles exhibiting a photocatalytic action are dispersed on a transparent substrate and the photoactive fine particles are dispersed. A coating made of a metal oxide is formed on the transparent substrate so as to cover the transparent substrate.

Further, since the above-mentioned substrate with a photocatalyst film is required to have excellent transparency, the metal oxide is required to have good transparency. It is preferable to use silicon oxide as the material.

The substrate with a photocatalyst film is prepared by suspending photoactive fine particles in a solvent such as water in advance to prepare a suspension, and spraying the suspension on a glass substrate with a spray gun or the like. After that, heat treatment is performed to evaporate the liquid, thereby fixing the photoactive fine particles to the glass substrate, and thereafter, by performing a sputtering process using a predetermined metal material (for example, silicon) as a target material, easily manufactured. be able to.

That is, according to the method of manufacturing a substrate with a photocatalytic film according to the present invention, after photoactive fine particles exhibiting a photocatalytic action are scattered on a transparent substrate, heat treatment is performed, and thereafter, sputtering is performed using a predetermined metal material as a target. Alms,
Forming a coating made of a metal oxide on the transparent substrate on which the photoactive fine particles are dispersed; further preparing the suspension by suspending the photoactive fine particles in a predetermined solvent; After the turbid liquid is sprayed on the transparent substrate, the heat treatment is performed to evaporate the suspension on the transparent substrate, thereby fixing the photoactive fine particles on the transparent substrate.

According to the above-described manufacturing method, the photoactive fine particles are spread on the transparent substrate without immersing the transparent substrate in the suspension as in the prior art, and then the sputtering process is performed. Even when used as a large-sized glass article, it can be easily mass-produced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view schematically showing a substrate with a photocatalytic film according to the present invention.

In FIG. 1, reference numeral 1 denotes a glass substrate made of soda lime or the like. The surface of the glass substrate 1 has a particle size of 5 nm to 10 nm having an anatase crystal structure.
TiO ₂ fine particles (photo-active fine particles) 2 are dispersed, and the glass substrate 1 is further covered with S 2 so as to cover the TiO ₂ fine particles 2.
An TiO ₂ film 3 (coating) is formed, and the TiO ₂ fine particles 2 and Si
The O ₂ film 3 forms the photocatalytic film 4.

In the present embodiment, the photocatalyst film 4 has a composition ratio of TiO ₂ and SiO ₂ in weight% of TiO _2.
/ SiO ₂ = 20/80 to 50/50.

The reason why the composition ratio of TiO ₂ and SiO ₂ is set to TiO ₂ / SiO ₂ = 20/80 to 50/50 by weight% is as follows.

The ratio of TiO ₂ to SiO ₂ is 20 wt.
%, The SiO ₂ content is 80% or more, so that the thickness of the SiO ₂ film is large, and thus the mechanical strength of the film itself is excellent.
_{(2) Since} the content of the fine particles 2 is low, a desired photocatalytic reaction cannot be promoted, and consequently, contaminants on the film surface cannot be sufficiently decomposed, and a desired self-fouling property is secured. Can not.

On the other hand, when the ratio of TiO ₂ to SiO ₂ is 5
When the content exceeds 0 wt%, the content of the TiO ₂ fine particles 2 in the photocatalytic film 4 increases to 50 wt% or more, so that the self-fouling property is excellent, but the SiO ₂ content in the film is small. As a result, the thickness of the SiO ₂ film 3 also becomes thin, so that the film surface is easily scratched, the peeling resistance is reduced, and the mechanical strength is deteriorated.

Therefore, in the present embodiment, TiO ₂ and Si
The composition ratio of O ₂ is TiO ₂ / SiO ₂ = 20/80 by weight%.
５０50/50.

Next, a method of manufacturing the substrate with a photocatalytic film will be described.

FIG. 2 is a manufacturing process diagram showing the manufacturing process of the substrate with a photocatalytic film.

That is, a glass substrate 1 of a predetermined shape made of soda lime or the like is prepared.
_{(2) The} suspension in which the fine particles 2 are suspended is sprayed on the glass substrate 1. Specifically, first, TiO ₂ fine particles 2 having an anatase type crystal structure and having a particle size of 5 nm to 10 nm are suspended in an aqueous solution and a binder (for example, a phosphorus-based substance)
By mixing the aqueous solution, thereby TiO ₂ fine particles 2 5
Make a wt% suspension. After diluting the suspension, the diluted suspension is sprayed on the glass substrate 1.

As the above-mentioned suspension, it is preferable to use a commercially available photocatalyst solution from the viewpoint of production efficiency. For example, TKC-304 manufactured by Teica Co., Ltd. can be used.

Next, the process proceeds to a heat treatment step 6 where the temperature is 150
About 30 minutes to 60 minutes at about 300 ° C. to 300 ° C., glass substrate 1
Is heated to evaporate the suspension adhered on the glass substrate 1.

Next, the process proceeds to the sputtering step 7 where Si
Is used as a target material, a sputtering process is performed under a predetermined reduced pressure using a mixed gas of Ar and O ₂ as a sputtering gas to form a SiO ₂ film 3 on the surface of the glass substrate 1 containing the TiO ₂ fine particles 2, A firing process is performed accordingly. That is, the process proceeds to the firing step 8 as necessary,
By performing the baking treatment under a temperature condition of 00 ° C. to 500 ° C., the adhesion of the coating can be improved. Then, the desired photocatalytic film 4 is formed on the glass substrate 1 in this manner.
Is formed, and a substrate with a photocatalytic film is obtained.

FIG. 3 is a diagram showing the details of the above-mentioned manufacturing method. In the present embodiment, as shown in FIG. 3, a series of manufacturing steps are continuously performed, whereby a desired substrate with a photocatalytic film is obtained. Can be easily mass-produced.

That is, in the spraying step 5, the above-mentioned suspension is supplied to the spray gun 9, and the suspension is sprayed from the spray gun 9 onto the glass substrate 1 moving on the conveyor 10 in the direction of arrow A. Thereby, the TiO ₂ fine particles 2 are fixed to the glass substrate 1 via the binder in the suspension. Next, in a heat treatment step 6, the glass substrate 1 is heated by the heater 11.
Is heated at 150 ° C. to 300 ° C. for 30 minutes to 60 minutes to evaporate the moisture adhering on the glass substrate 1.

Next, the process proceeds to a sputtering step 7, where a predetermined sputtering process is performed using the sputtering apparatus 12.

The sputtering device 12 is, specifically,
It has a gas inlet 13 for introducing a sputtering gas, a vacuum exhaust port 14 for reducing the pressure inside the apparatus, and opening / closing valves 15a and 15b for supplying and discharging the glass substrate 1 as a film-forming object. are doing. Two cathodes (first and second cathodes 16a and 16b) to which a negative voltage is applied by a DC power supply are provided at the upper part of the apparatus, and a heater 17 is provided at the lower part of the apparatus. I have.

Then, in the sputtering apparatus 12,
Silicon is adhered as a target material 18 to the lower surfaces of the first and second cathodes 16a and 16b, and a sputtering gas is supplied to the gas inlet 1 under predetermined sputtering conditions.
The target material 18 is irradiated with the accelerated sputtering gas ions supplied from 3 and accelerated, thereby causing the sputtering gas ions to fly off. On the other hand, the glass substrate 1 is heated to 100 ° C. to 350 ° C. by the heater 17.
And is conveyed on the conveyor 10 in the direction of arrow B,
Sputtering gas ions flipped off from the first and second cathodes 16a and 16b are deposited on the surface of the glass substrate 1, and an SiO ₂ film 3 is formed on the glass substrate 1. In this sputtering step 7, sputtering is performed using two cathodes 16a and 16b, but one or two cathodes may be used as appropriate according to the thickness of the SiO ₂ film to be formed. The sputtering process is performed.

After the completion of the above-mentioned sputtering process, a firing process may be carried out at a temperature of 200 ° C. to 500 ° C., if necessary, in order to improve the adhesion of the film.

As described above, in the present embodiment, after the suspension is sprayed on the glass substrate 1 by the spray gun 9, heat treatment is performed, and then the first and second cathodes 16a, 16b
, The SiO ₂ film 3 having a desired thickness is easily formed on the glass substrate 1 so as to cover the TiO ₂ fine particles 2. In addition, since the glass substrate 1 is not immersed in the suspension but the suspension is sprayed on the glass substrate 1 and the TiO ₂ fine particles 2 are fixed on the glass substrate 1, the glass substrate 1 is large-sized. Even in this case, mass production can be easily performed.

The present invention is not limited to the above embodiment.

[0038] In the above embodiment, by using the TiO ₂ fine particles 2 having a crystal structure of anatase as the light active particulate, Tayca Corporation under the commercial suspension of TiO ₂ fine particles 2 of such anatase TKC-304 is exemplified, but it goes without saying that other commercially available suspensions can be used as long as the photoactive fine particles can be dispersed and fixed on the glass substrate.

In the above embodiment, the film is formed of SiO.
₂ shows the case where the film 3 is formed, but the film is formed of SiO ₂ −
It is also preferable to form the film by Al ₂ O ₃ or a mixed film of SiO _{2 and} TiO ₂ .

That is, Al ₂ O ₃ or TiO ₂ is S
Since the refractive index is higher than that of iO ₂ , the glass substrate 1 is formed by forming a coating so as to have a composition gradient such that the content of SiO ₂ increases gradually as the distance from the surface of the glass substrate 1 increases. The refractive index gradually decreases from the side to the film surface, whereby the reflectance from the glass substrate 1 can be reduced. Moreover, since SiO ₂ has excellent hydrophilicity, by forming SiO ₂ on the film surface side, it is possible to easily remove contaminants by washing with water or the like.

In this case, for example, when forming a mixed film of SiO _{2 and} TiO _{2 on} the glass substrate 1, titanium is set as the target material in the first cathode 16a of FIG. Sets silicon as a target material, and performs a sputtering process under predetermined sputtering conditions while moving the glass substrate 1 on which the TiO ₂ fine particles 2 are fixed in the direction of arrow B, thereby increasing the SiO ₂ component near the film surface. A mixed film having a composition gradient as described below can be formed.

In particular, in this case, by narrowing the distance between the first cathode 16a and the second cathode 16b, a photocatalytic film having a desired composition gradient can be obtained smoothly.

In addition, at least one element selected from the group consisting of Fe (iron), Al (aluminum), Ni (nickel) and V (vanadium) is added to the suspension in a trace amount (for example, 0.1 wt%). ) Is also preferred. Specifically, for example, when Fe is contained, Fe
Ore dissolved in sulfuric acid, or acetylacetonato complex of Fe or ethylenediamine tetracomplex of Fe (F
A mixture of a chelate compound such as e-EDTA) and a suspension is used. Then, a small amount of F
By adding e, Al, Ni, V, etc., the light absorption edge in the light transmission spectrum of the film can be shifted to the longer wavelength side by 5 nm or more, and therefore, the light absorption characteristics of the TiO ₂ fine particles 2 dispersed therein In combination with this, light can be absorbed in a wider wavelength range, and a larger catalytic activity can be obtained.

[0044]

Next, embodiments of the present invention will be described specifically.

The present inventors respectively prepared test pieces falling within the scope of the present invention (Examples 1 to 3) and test pieces falling outside the scope of the present invention (Comparative Examples 1 to 2). Each was evaluated for film properties.

Example 1 First, a spray liquid (suspension) in which TKC-304 manufactured by Teica having the following liquid properties was diluted 1/10 and TiO ₂ fine particles having an anatase type crystal structure were suspended. ) Was prepared.

[Liquid Properties of TKC-304] Solvent: Water Hydrogen ion concentration: Neutral (pH = 7) TiO ₂ concentration: 5 wt% Ti shape: Anatase crystal Binder: Phosphorus Is spread on the glass substrate 1 by using, and then the glass substrate 1 is
The TiO ₂ fine particles 2 were fixed on the glass substrate 1 by heating at a temperature of 200 ° C. to evaporate the water on the glass substrate 1. Next, Si containing a small amount of B (boron) is used as the target material 18, and a mixed gas of Ar and O ₂ (Ar / O ₂ = 40 /
60), the gas pressure was adjusted to 0.4 Pa, and a sputtering process was performed. Then, the SiO ₂ film 3 is formed on the glass substrate 1 so as to cover the TiO ₂ fine particles 2.
Was formed, and a test piece of Example 1 was produced.

The supply amount of the sputtering gas is as follows:
The ratio of TiO _{2 to} SiO ₂ , that is, TiO ₂ / Si
O ₂ was prepared so that TiO ₂ / SiO ₂ = 40/60, and the thickness of the formed SiO ₂ film 3 was 300 nm.

Embodiment 2 Fe-
A solution containing 0.5% by weight of EDTA was diluted 1/10 to prepare a spray liquid, and the spray liquid was sprayed on the glass substrate 1 with a spray gun 9, and then the glass substrate 1 was sprayed for 30 minutes. Glass substrate 1 heated at a temperature of 200 ° C.
The TiO ₂ fine particles 2 were fixed on the glass substrate 1 by evaporating the moisture adhering to the substrate. Next, target material 1
8 as a Si-Al alloy (Si: 90 wt%, Al: 1)
(0 wt%), and subjected to a sputtering process in substantially the same manner as in Example 1. Then, after forming the SiO ₂ film 3 on the glass substrate 1 in this manner, a baking treatment was performed at a temperature of 500 ° C., and a test piece of Example 2 was produced.

In the second embodiment, the supply amount of the sputtering gas is such that TiO ₂ / SiO ₂ is TiO ₂ / Si
O ₂ = 30/70
The thickness of the O ₂ film 3 was 500 nm.

[Embodiment 3] Al-
A solution containing 0.1 wt% of EDTA was diluted 1/10 to prepare a spray solution, and the spray solution was sprayed on the glass substrate 1 by a spray gun 9, and then subjected to the same heat treatment and sputtering as in Example 1. Glass substrate 1
An SiO ₂ film 3 was formed thereon, and thereafter, a baking treatment was performed at a temperature of 500 ° C., thereby producing a test piece of Example 3.

In the third embodiment, the supply amount of the sputtering gas is such that TiO ₂ / SiO ₂ is TiO ₂ / Si
O ₂ = 50/50
The thickness of the O ₂ film 3 was 400 nm.

COMPARATIVE EXAMPLE 1 Next, the inventors of the present invention
A test piece in which the TiO ₂ fine particles 2 were exposed on the glass substrate 1 without forming the _two films 3 was prepared.

That is, a solution obtained by diluting TKC-304 to 1/10 was used as a spray liquid, and the spray liquid was sprayed on the glass substrate 1 with a spray gun 9, and then the glass substrate 1 was sprayed at 200 ° C. for 60 minutes. The test piece of Comparative Example 1 was manufactured by heating at a temperature to completely evaporate the moisture attached to the glass substrate 1.

[Comparative Example 2] Next, the inventors of the present invention reported that TiO 2
A test piece was prepared by laminating _two films on a glass substrate by sputtering.

That is, as the target material 18, Ti
Using a metal, a mixed gas of Ar and O ₂ (Ar / O ₂ = 50/50) is used as a sputtering gas, the gas pressure is adjusted to 0.4 Pa, and a sputtering process is performed. Then, a TiO ₂ film was laminated thereon to prepare a test piece of Comparative Example 2.

Next, the film properties (self-fouling property, mechanical strength, hydrophilicity) of each of the above test pieces were evaluated.

The self-stain resistance was evaluated by leaving each test piece outdoors for one month and comparing the stain condition with the glass substrate alone. The mechanical strength is determined according to JIS R3221.
6.4. Abrasion test (load 100g / c)
m ² ) and evaluated by the presence or absence of surface damage. Further, the hydrophilicity was evaluated by spraying water on each of the test pieces and visually checking the repellency of the water.

Table 1 shows the film properties of each test piece.

[0060]

[Table 1]

In Table 1, with respect to the self-contamination resistance, ◎ indicates that there was a clear effect as compared with the glass substrate alone, and Δ indicates that there was some effect as compared with the glass substrate alone. The crosses indicate the case where no effect was observed as compared with the glass substrate alone. Regarding mechanical strength, ◎ indicates good, Δ indicates acceptable, and × indicates unacceptable. Regarding the hydrophilicity, the symbol 〇 indicates that water occupies an area of 60% or more on the membrane surface and spread, and the symbol x indicates that water occupies less than 30% of the area on the membrane surface. .
In addition, in this example and a comparative example, water is 30 to 60% on the film surface.
Was not obtained.

As is clear from Table 1, in Comparative Example 1, since the TiO ₂ fine particles 2 were fixed on the glass substrate 1, the TiO ₂ fine particles caused a catalytic reaction by light irradiation to decompose contaminants on the surface. it is, therefore compared to the glass substrate itself which TiO ₂ fine particles 2 are not fixed, but self antifouling properties is good, TiO ₂ fine particles from the glass substrate of TiO ₂ fine particles because they are not covered by the SiO ₂ film peeling inferior in mechanical strength occurs, also, TiO ₂ is Si
Since it does not have an affinity for water unlike O ₂ , it was confirmed that it was inferior in hydrophilicity.

Comparative Example 2 was excellent in mechanical strength because only a TiO ₂ film was formed on a glass substrate.
With respect to self-staining properties, it was confirmed that the same degree of stains as in the case of the glass substrate alone remained, and that the hydrophilicity was poor.

On the other hand, in Examples 1 to 3, the TiO ₂ fine particles 2 were fixed on the glass substrate 1,
SiO ₂ film 3 on glass substrate 1 so as to cover O ₂ fine particles 2
Is formed, when irradiated with light, the photocatalytic reaction by the TiO ₂ fine particles 2 is promoted to improve the self-contamination resistance, and the TiO ₂ fine particles 2 are covered with the SiO ₂ film 3 to provide a mechanical strength. or scratched greatly improved the surface, or the photocatalyst film 4 (TiO ₂ fine particles 2 and the SiO ₂ film 3) is avoided that peeled from the glass substrate 1, SiO ₂ film 3 is further formed a coating Since it has affinity for water, good results can be obtained for hydrophilicity.

[0065]

As described above in detail, in the substrate with a photocatalytic film according to the present invention, photoactive fine particles exhibiting a photocatalytic action are scattered on a transparent substrate, and the transparent substrate covers the photoactive fine particles. As described above, since a coating made of a metal oxide (silicon oxide) is formed, the photocatalytic action of the photoactive fine particles is not impaired, and therefore, it has a good self-fouling property and also has excellent durability. Thus, a substrate with a photocatalyst film can be obtained.

Further, in the method of manufacturing a substrate with a photocatalytic film according to the present invention, a photoactive fine particle exhibiting a photocatalytic action is dispersed on a transparent substrate, and then subjected to a heat treatment, and thereafter, a predetermined metal material (silicon) is treated with a target material. A sputtering process is performed to form a coating made of a metal oxide on the transparent substrate on which the photoactive fine particles are dispersed, and a suspension is prepared by suspending the photoactive fine particles in a predetermined solvent. After the suspension is sprayed on the transparent substrate, the heat treatment is performed to evaporate the suspension on the transparent substrate, and the photoactive fine particles are fixed on the transparent substrate. As described above, by dispersing the photoactive fine particles on the transparent substrate without immersing the transparent substrate in the suspension, it is possible to easily mass-produce a substrate with a photocatalytic film that can be used for various glass articles.

Further, in the present invention, since the photoactive fine particles can be embedded in the coating made of metal oxide having a small refractive index, the reflected color can be made inconspicuous.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a substrate with a photocatalytic film according to the present invention.

FIG. 2 is a manufacturing process diagram showing a method for manufacturing a substrate with a photocatalytic film according to the present invention.

FIG. 3 is a diagram showing details of a method for manufacturing the substrate with a photocatalytic film.

[Explanation of symbols]

Reference Signs List 1 glass substrate (transparent substrate) 2 TiO ₂ fine particles (photoactive fine particles) 3 SiO ₂ film (coating)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuro Kawahara 3-1-1, Doshomachi, Chuo-ku, Osaka-shi, Osaka Inside Nippon Sheet Glass Co., Ltd. (72) Daisuke Arai 3-chome, Doshucho, Chuo-ku, Osaka-shi, Osaka No. 5-11 Nippon Sheet Glass Co., Ltd. F-term (reference) 4G059 AA01 AA07 AB01 AB09 AB11 AC22 EA04 EA05 EA18 EB04 EB06 GA01 GA05 GA12 4G069 AA03 AA08 AA11 BA02A BA02B BA04A BA04B BA48A BB04A BB04B05A04 BB04B05A05 BA46 BD00 CA06

Claims (5)

[Claims] 1. A photo-active fine particle exhibiting a photocatalytic action is spread on a transparent substrate, and a coating made of a metal oxide is formed on the transparent substrate so as to cover the photo-active fine particles. Substrate with a photocatalytic film. 2. The substrate with a photocatalytic film according to claim 1, wherein the metal oxide is a silicon oxide. 3. The transparent substrate on which the photoactive fine particles exhibiting the photocatalytic action are sprayed on a transparent substrate and then subjected to a heat treatment, and then subjected to a sputtering process using a predetermined metal material as a target material. A method for producing a substrate with a photocatalytic film, comprising forming a film made of a metal oxide thereon. 4. The method according to claim 3, wherein said predetermined metal material is silicon. 5. A suspension in which the photoactive fine particles are suspended in a predetermined solvent to prepare a suspension, and the suspension is sprayed on the transparent substrate, and then subjected to the heat treatment to perform a heat treatment on the transparent substrate. The method for producing a substrate with a photocatalyst film according to claim 3 or 4, wherein the suspension is evaporated to fix the photoactive fine particles on the transparent substrate.