Photocatalyst element, method and device for preparing the same

TECHNICAL FIELD The present invention relates to a photocatalyst body, a method of manufacturing a photocatalyst body, and a photocatalyst body manufacturing apparatus, and particularly relates to the promotion of the production of an active body by light irradiation The photocatalyst body, the manufacturing method of the photocatalyst body, and the manufacturing apparatus of the photocatalyst body.

2. Description of the Related Art In recent years, a photocatalyst thin body using titanium dioxide has attracted attention. "Photocatalyst" refers to a substance that has semiconductor characteristics, and when it is irradiated with energy light that is larger than the band gap energy of its own conductive electron band and charge band, it will be in an excited state to generate electron and hole pairs.

Titanium dioxide with an anatase crystal structure is irradiated with light with a wavelength of 387 nm or less, and it is excited by light, and at the same time it causes a decomposition reaction based on an oxidation-reduction reaction and a hydrophilic reaction opposite to the decomposition reaction (activity). At present, it is known that the metal oxides that cause these two reactions at the same time are titanium oxide, tin oxide, and zinc oxide. The metal oxides that only cause the decomposition reaction are known titanate and ferrous oxide, and the metal oxides that only cause the hydrophilic reaction. There are three oxide hooks.

Moreover, the characteristics of the above-mentioned substances can be used to obtain self-cleaning effects, decontamination effects, antibacterial effects, etc., and various materials and products covering the photocatalyst body have been proposed.

As a manufacturing method of such a photocatalyst body, various methods such as a binder method, a sol-gel method, and a vacuum vaporization method have been proposed.

The adhesive method refers to a method in which fine particles of titanium oxide are sprayed on an adhesive with adhesive properties, applied to a predetermined substrate, and then heated and dried. However, the use of this method will bury the particulate titanium oxide between the binders, so the problem of affecting the function of the photocatalyst body is likely to occur.

In addition, the sol-gel method refers to applying solvents such as titanium-containing chelated titanium and titanium alkoxide to a predetermined substrate, drying it, and calcining it at a high temperature of 500°C or more to produce a photocatalyst

02821432.3 Dikang. However, since it has to go through a high-temperature burning process of more than 500 Ό, it is prone to extremely restricted matrix material selection in terms of heat resistance.

In view of the shortcomings of these manufacturing methods, it is recommended to use manufacturing methods such as vacuum evaporation and sputtering.

For example, in Patent No. 2901550, it has been clearly proposed to use a vacuum filling method to form a photocatalyst body with a laminated structure of titanium oxide and silicon oxide.

In addition, in Patent Publication No. 2000-126613, a method of depositing silicon oxide using a reactive sputtering method has been clearly proposed.

In response to this, the inventors used a sputtering method to form a titanium oxide film under various conditions and evaluated various material properties. As a result, they found that the titanium oxide film formed under different conditions from the past has a unique structure different from the past. Furthermore, in these titanium oxide films, it was found that the characteristics of the photocatalyst body were significantly improved compared with the above-mentioned conventional titanium oxide films.

The present invention is based on a known principle, and its purpose is to optimize the characteristics of the photocatalyst body and improve the production performance. At the same time, it also provides a photocatalyst body with good maintenance characteristics in the dark, a method for manufacturing a photocatalyst body, and a photocatalyst body. Manufacturing device.

SUMMARY OF THE INVENTION The first type of photocatalyst body of the present invention is a photocatalyst body having a photocatalytic film composed of a titanium oxide compound. The photocatalytic film is porous, and the ratio of the arithmetic average surface roughness Ra to the film thickness is 0.02 or more. , This is the characteristic of the catalyst.

Therefore, the arithmetic average roughness Ra of the surface of the photocatalyst body can be 1.3 nm or more.

The second type of photocatalyst body of the present invention is a photocatalyst body having a photocatalytic film composed of a titanium oxide compound. The photocatalyst film is porous and has a (112) diffraction peak with a titanium oxide anatase structure. The intensity ratio of the (101) diffraction peak of the mineral structure is below 5, which is the characteristic of the catalyst.

The third type of photocatalyst body of the present invention is a photocatalyst body having a photocatalytic film composed of a titanium oxide compound. The photocatalyst film is porous and has a (215) diffraction peak of titanium oxide anatase structure and titanium oxide anatase The intensity ratio of the (101) diffraction peak of the ore structure is below 100, which

02821432.3 The first feature is the catalyst.

In any of the aforementioned photocatalyst bodies, the thickness of the photocatalytic film is between 40 nm and 100 nm.

A buffer layer made of silicon oxide may be provided under the above-mentioned photocatalytic film.

The refractive index of the photocatalyst body is 2.7 or less.

A silicon oxide film may be provided above the photocatalytic film.

In this case, the thickness of the aforementioned silicon oxide film is between 3 nm and 7 nm.

In addition, the method for producing a photocatalyst body of the present invention is a method for producing a photocatalyst body having a photocatalyst film composed of a titanium oxy compound, by sputtering a target containing titanium under an oxygen-containing atmospheric condition, with a temperature of less than 0.6 nm/sec. The film formation rate deposits the above-mentioned photocatalytic film, which is a characteristic of the catalyst.

Therefore, when the film formation speed is R and the surface temperature of the photocatalytic film deposition is T, the photocatalytic film can be deposited at a temperature that satisfies the formula R^2.36exp(-410(l/T)). membrane.

The second method of manufacturing a photocatalyst body of the present invention is a method for manufacturing a photocatalyst body of a photocatalyst film composed of a titanium oxy compound by sputtering a target containing titanium under atmospheric conditions containing 3 Pascals to 5 Pascals of oxygen. Depositing the above-mentioned photocatalytic film is a characteristic of the catalyst.

The third method for manufacturing a photocatalyst body of the present invention is a method for manufacturing a photocatalyst body having a photocatalytic film composed of a titanium oxy compound. The target is deposited by sputtering a target containing titanium under atmospheric conditions containing 10% to 30% oxygen. The accumulation of the above-mentioned photocatalytic film is a characteristic of the catalyst.

In the first to third methods of manufacturing a photocatalyst body, a buffer layer made of silicon oxide may be deposited before depositing the above-mentioned photocatalytic film.

Furthermore, it may include a step of depositing silicon oxide on the photocatalyst body.

In addition, the photocatalyst body manufacturing apparatus of the present invention is a photocatalyst body manufacturing apparatus having a photocatalyst film composed of a titanium oxy compound, and is equipped with a first type of film forming chamber capable of maintaining a pressure lower than atmospheric pressure, and the above-mentioned first type of film is formed. The chamber is equipped with a power supply for supplying voltage to the target, a heating means for heating the substrate, a gas introduction device for introducing a reactive gas including oxygen into the first type of film forming chamber, and a controller that can control the heating device. Film forming chamber

02821432.3 First, sputtering is used to form a photocatalytic film composed of a titanium oxide compound on the substrate, and the controller controls the heating means so that the film formation rate R of the photocatalyst body and the temperature T of the substrate surface satisfy the formula RW2 ,36exp(410(l/T)), which is the characteristic of the manufacturing device.

Therefore, when the photocatalyst film is sputtered, the controller controls the gas introduction device so that the pressure in the first type film forming chamber is 3 Pascals to 5 Pascals.

When the photocatalytic film is sputtered, the controller controls the gas introduction device so that the oxygen content in the first type film forming chamber is between 10% and 30%.

It is even equipped with a heating chamber with the heating device, and a transport device for transporting the substrate from the heating chamber to the first type of film forming chamber. After the substrate is heated in the heating chamber, the substrate can be transported by the transport device. To the above-mentioned first type film forming chamber, the above-mentioned photocatalytic film is sputtered.

Equipped with a second type of film forming chamber capable of forming a silicon oxide film, it is possible to form a silicon oxide film on the substrate before sputtering the photocatalyst body.

Equipped with a third type of film forming chamber capable of forming a silicon oxide film, a silicon oxide film can be formed on the substrate after the photocatalyst body is sputtered.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing the structure of a photocatalyst body in a state where the present invention is implemented.

FIG. 2 is a schematic diagram of the surface of the photocatalytic film 10.

FIG. 3 is a schematic diagram showing the cross-sectional structure of the photocatalytic film 10.

Fig. 4 is a schematic diagram showing the configuration of important parts of the sputtering apparatus used in the experiment.

Fig. 5 is a graph showing the temperature change of the substrate 100 during sputtering.

Figure 6 is an electron micrograph of the surface of the photocatalytic film obtained by reactive sputtering.

Figure 7 is an electron micrograph of the surface of the photocatalytic film obtained by reactive sputtering.

FIG. 8 is a graph showing an example of the result of the paraffin decomposition and hydrophilicity experiment of the photocatalytic film 10 using the present invention.

02821432.3 Figure 9 is a graph showing the relationship between the surface finish and contact angle of the photocatalytic film measured by AMF (Atomic Force Microscopy: Atomic Force Microscopy).

Figure 10 is a graph depicting the contact angle of the ratio Ra/T of the surface roughness Ra of the samples A to D to the respective film thickness.

Fig. 11 is a graph showing the X-ray diffraction pattern of the photocatalytic film of Sample C.

Figure 12 is the diffraction pattern after data processing is performed on the diffraction pattern of Figure 10 to remove background noise.

Figure 13 is a graph obtained by performing the same X-ray diffraction pattern measurement on the photocatalytic film of Sample A and removing the background noise.

Figure 14 is a graph plotting the refractive index and density ratio under all pressures.

Figure 15 is a list of the photocatalytic film formation conditions of the implementation examples by the present inventors using the DC sputtering method.

Fig. 16 is a list of the film forming conditions of the photocatalytic film of the comparative example by the present inventors using the DC sputtering method.

Fig. 17 is a graph showing the relationship between the oxygen partial pressure during sputtering and the contact angle of the obtained photocatalytic film.

Fig. 18 is a graph showing the relationship between the total pressure during sputtering and the contact angle of the obtained photocatalytic film.

Fig. 19 is a graph showing the relationship between the film formation speed during sputtering and the contact angle of the obtained photocatalytic film.

Figure 20 is a graph showing the relationship between the film thickness of the photocatalytic film formed by sputtering and the contact angle.

Figure 21 is a flowchart showing the procedure of the wet decomposition performance test.

Figure 22 is an example of a graph showing the results of the wet decomposition performance test.

Fig. 23 is a schematic diagram showing an example of the cross-sectional structure of a photocatalyst body provided with a buffer layer.

Figure 24 is a graph showing the results of the paraffin decomposition and hydrophilicity test.

Fig. 25 is a schematic diagram showing a cross-sectional structure of a photocatalyst body according to a second embodiment of the present invention.

02821432.3 Figure 26 is an example showing the result of the paraffin decomposition hydrophilicity test of the photocatalytic film with the layered structure of Figure 25.

Fig. 27 is a graph showing the results of the paraffin decomposition hydrophilicity test of the photocatalytic film according to the second embodiment of the present invention.

Fig. 28 is a graph showing the results of the paraffin decomposition hydrophilicity test of the photocatalytic film according to the second embodiment of the present invention.

Fig. 29 is a graph showing the results of the paraffin decomposition hydrophilicity test of the photocatalytic film according to the second embodiment of the present invention.

Fig. 30 is a graph showing the change in contact angle when the photocatalytic film according to the second embodiment of the present invention is maintained in a dark place.

Figure 31 is a graph showing the photocatalytic action of the photocatalyst bodies of the present invention and the comparative example.

Figure 32 is a graph showing a sample DX-ray diffraction pattern.

Figure 33 is a graph showing the IX line diffraction pattern of Comparative Example.

Figure 34 is a graph showing the photocatalytic effects of the photocatalyst bodies of the present invention and the comparative example in comparison.

Figure 35 is a graph showing the photocatalytic action of the photocatalyst body of the present invention and the comparative example in comparison.

Fig. 36 is a conceptual diagram illustrating the configuration of important parts of the photocatalyst body manufacturing apparatus of the present invention.

Fig. 37 is a conceptual diagram showing the configuration of important parts of an example Ti()2 film forming chamber 230 (or 240).

Fig. 38 shows a modified example of the manufacturing apparatus of the photocatalyst body of the present invention.

Fig. 39 is a vertical cross-sectional view of the TiC) 2 film forming chambers 230 and 240.

DESCRIPTION OF EMBODIMENTS In order to explain the present invention in more detail, the present invention will be explained based on the drawings. As a result of independent research and experiments conducted by the present inventors, it is shown that the activity of photocatalytic materials such as titanium oxide can be significantly improved after being porous. The reactive sputtering method has greatly improved the cost compared with the past.

02821432.3 The first film speed, at the same time, by adjusting the sputtering pressure and substrate temperature within an appropriate range of film forming parameters, Ogi obtained this porous photocatalyst body material, which has different material properties from the past.

Moreover, the porous photocatalyst body material can be covered with silicon oxide with a predetermined film thickness, which does not actually hinder the function of the photocatalyst body, can protect the surface, and has excellent dark space maintenance characteristics.

The embodiments of the present invention will be described in detail below with reference to specific examples.

(First Embodiment) First, a porous photocatalytic film according to the first embodiment of the present invention and a method of manufacturing the same will be described.

Fig. 1 is a schematic diagram illustrating the structure of a photocatalyst body illustrating the implementation state of the present invention.

In other words, the photocatalyst body of the present invention is covered with a thin-film photocatalytic film 10 on a predetermined substrate 100. Titanium oxide (TiOx) is used as the material of the photocatalytic film 10. In the present invention, this oxidation The photocatalytic film 10 made of titanium is porous.

FIG. 2 is a schematic diagram of the surface state of the photocatalytic film 10. That is, the figure shows the surface of a photocatalytic film with a film thickness of 135 nm formed on a substrate with titanium oxide. A large number of particles G of 10nm or less can be seen on this surface, but these particles must be densely filled to form gaps S between particles.

FIG. 3 is a schematic diagram showing a cross-sectional view of the photocatalytic film 10. As shown in the figure, a gap S is formed between countless particles G, and a film structure with a very large surface area is obtained.

Such a porous photocatalyst film 10 greatly improves the function of the photocatalyst body compared with the past.

Hereinafter, the photocatalytic film of the present invention will be described in detail with reference to its manufacturing method.

The photocatalytic film of the present invention is produced by a reactive sputtering method.

Fig. 4 is a schematic diagram showing the configuration of important parts of the sputtering apparatus used in the experiment. That is, inside the vacuum chamber 101, a target 102 made of metallic titanium is provided in contact with the cathode 103. On the contrary, a substrate 100 on which a photocatalytic film is deposited is provided on the anode 104 side.

At the time of film formation, first, the chamber 101 is brought into a vacuum state by the vacuum exhaust pump 106, and the discharge gas of hydrogen (Ar) and oxygen (02) is introduced from the gas supply source 107. Then, Lee

02821432.3 The first power supply 110 applies an electric field between the anode 104 and the cathode 103 to start the plasma discharge 108. Then, sputtering to the surface of the target 102 is started, and metal titanium and oxygen are combined on the substrate 100 to form a titanium oxide film 10. Therefore, the power supplied from the power source 110 may be either a DC (direct current) power source or an RF (high frequency wave) power source.

In the following specific examples, unless otherwise specified, the DC sputtering method of a DC power supply is used to form the photocatalytic film.

Also, at the time of sputtering, the substrate 100 is placed in the reaction chamber 101 (ground potential). As will be described later, in such a sputtering device, a photocatalytic film with a predetermined film quality is obtained by adjusting the supply power of plasma discharge, the pressure and composition of the surrounding gas during sputtering, the temperature of the substrate, and the like.

Then, the temperature of the substrate 100 is confirmed by the thermostatic label 109 attached to it.

Fig. 5 is a graph showing an example of the temperature change of the substrate 100 during sputtering. The film-forming conditions A-C are the temperature change of the substrate temperature from room temperature to the start of sputtering. The conditions are as follows.

Conditional supply DC power, deposition rate, full pressure, oxygen partial pressure

A 2kW

18nm/min IPa

30%

B 2kW

22nm/min

3.5Pa

30%

C 3kW

36nm/min 5Pa

30% It can be seen from Fig. 5 that when sputtering starts with room temperature as the substrate temperature, the temperature of the substrate 100 rises with time due to the thermal radiation from the sputtering source, corresponding to the tendency of the supply power to reach the saturation temperature.

The saturation temperature mainly depends on the power supply. When the power is 2kW, the temperature is approximately

230°C; when the power is 3kW, the temperature is about 300°C.

However, film deposition sometimes ends before reaching the saturation temperature. For example, the deposition rate of condition C is 36 nm/min, and the time required to form a titanium oxide film with a film thickness of 135 nm is 3 minutes and 45 seconds, so the maximum substrate temperature when the deposition starts from room temperature is about 230°C. In addition, since air needs to be removed before sputtering, the substrate can be heated in advance to start sputtering from a state higher than room temperature. In this case, since the state where the temperature starts to rise is close to the saturation temperature, the temperature may sometimes be lower than the saturation temperature during the deposition when heating in advance.

Figures 6 and 7 are electron displays on the surface of the photocatalytic film obtained by reactive sputtering.

02821432.3 The micro-mirror photo. In other words, Figures (a) to (d) are surface photographs of samples A to D of the titanium oxide film, respectively.

Figures 6 and 7 are photos of the same sample at different magnifications. The length of the rod in the lower right corner of the photo in Figure 6 is 300nm, which is equivalent to 119nm in Figure 7.

The sample A was formed under the above condition A, the sample B was formed under the above condition B, and the samples C and D were formed under the above condition C. Moreover, any sample is deposited on the silicon wafer used as the substrate 100, through the SiO2 buffer layer, deposited titanium oxide as a photocatalytic film, the film thickness of the titanium oxide 10: sample A-C is 135nm, sample D is 50nm .

As shown in Figures 6 and 7, the surface of sample A has a dense structure of fine particles, and the particles are densely packed.

In contrast, countless particles with a diameter of tens of nm or less can also be seen on the surface of the sample B-D. These particles are not dense and have gaps. That is, it is porous.

Therefore, the particles of sample D are smaller than those of samples B and C, which can be considered to be due to the large difference in film thickness.

The photocatalytic effect of the photocatalytic film 10 thus obtained was evaluated by the "paraffin wax (WAX) decomposition hydrophilic test". In this test, after the photocatalyst body with the photocatalytic film 10 acts, it is a test for evaluating the "decomposition effect" and the "hydrophilic effect". "Decomposition" refers to the effect of decomposing organic materials such as paraffin wax by using active oxygen such as free radicals and superoxide generated on the surface of the photocatalyst body. "Hydrophilic effect" refers to the effect of improving the hydrophilicity of the surface of the photocatalytic film. The contents of the paraffin decomposition and hydrophilicity test carried out by the inventors are as follows: (1) The surface of the photocatalytic film 10 was washed with a neutral washing liquid to make it hydrophilic.

(2) Coat the surface of the photocatalytic film 10 with paraffin wax and dry at room temperature for 1 hour. The paraffin wax used here is produced by Shure Rast Company under the trademark "Hero", and its main ingredient is Brazilian palm wax.

(3) After cleaning the surface of the photocatalytic film 10 with a neutral washing liquid, it is dried at 50°C.

(4) While irradiating with invisible light (BLB), the contact angle of the water droplets formed on the surface of the photocatalytic film 10 is periodically measured. The paraffin wax formed on the surface of the photocatalytic film 10 is decomposed by the photocatalyst body because it is irradiated with invisible light (BLB). With paraffin remaining on the surface, the contact angle of the water droplets is large, and after the paraffin is decomposed, the contact angle of the water droplets becomes smaller.

02821432.3 Therefore, it can be said that even if the intensity of the invisible light is small, the more decomposed or the smaller the contact angle of the water droplets after the prescribed time is irradiated, the more active the photocatalyst body is.

FIG. 8 is a graph showing an example of the result of the paraffin decomposition and hydrophilicity experiment of the photocatalytic film 10 using the present invention. Here, data on the above-mentioned sample D in Figs. 5 to 7 is displayed. Moreover, the irradiation intensity of invisible light is 500pW/cm2, 50jiW/cm2, lO^W/cm²The data.

Here, the irradiation intensity of 500pW/cm2 is close to the usual paraffin decomposition hydrophilicity test, the irradiation intensity of 50pW/cin2 is slightly lower, and the irradiation intensity of 10yW/cm² is the lowest.

It can be seen from Figure 8 that the contact angle before the invisible light irradiation is about 83 degrees, but when the irradiation intensity is 500pW/cm2 and SOuW/cn?, the contact angle drops sharply while the invisible light is irradiated. About 9 degrees after hours, about 5 degrees after 2 hours, and about 3 degrees after 10 hours, the paraffin is quickly decomposed.

What's more interesting is that even with the ultra-weak light with an irradiation intensity of 1 OjiW/cn?, photocatalysis can be obtained. In other words, the rate of decrease of the contact angle is very slow, about 56 degrees after 3 hours, about 22 degrees after 6 hours, and dropped to 4 degrees after 12 hours. As described in detail below, compared with the past photocatalytic film, the effect of the photocatalyst body can be obtained under such ultra-weak light, which should be specifically explained.

The inventors adjusted various film forming conditions in the reactive sputtering method to form photocatalytic films of various film qualities. Hereinafter, the relationship between the material properties of the photocatalytic film and the film formation parameters will be sequentially described.

First of all, define the parameters of the "porosity" of the photocatalytic film uniformly, and pay attention to the "surface finish" of the film.

Figure 9 is a graph showing the relationship between the surface finish and the contact angle of the photocatalytic film measured by AMF (Atomic Force Microscopy: Atomic Force Microscopy). That is, the horizontal axis of the figure represents the surface roughness of the photocatalytic film made of titanium oxide. In addition, the vertical axis of Fig. 9 represents the contact angle of water droplets after being irradiated with invisible light (irradiation intensity of 500 jiW/cm2) for 1 hour in the same paraffin decomposition and hydrophilicity test as described above.

The four samples A-D depicted in Fig. 9 are the same as the samples A-D described in Figs. 5 to 8.

02821432.3 Figure 9 shows that when the photocatalytic film (Sample A) with a surface finish Ra of about 0.9 μm, even if the invisible light is irradiated for 1 hour, the contact angle is about 83 degrees, which is very large. In contrast, when the surface roughness Ra is 1.3nm (sample D), the contact angle rapidly drops to 9 degrees under the same conditions; when the surface roughness Ra is 3.5nm (sample B), the contact angle is about 8 degrees; When the surface roughness Ra is 3.65 nm (Sample C), the contact angle drops below 8 degrees.

In other words, if the surface roughness Ra is greater than 1 nm, the effect of the photocatalyst body increases rapidly.

Here we pay attention to the relationship between film forming conditions, film thickness, and surface finish, and draw the following conclusions:

<td>sample</td><td>Deposition rate</td><td>All pressure</td><td>Film thickness</td><td>Surface finish</td>

<td>A</td><td>]8nm copies</td><td>IPa</td><td>135nm</td><td>0.9nm</td>

<td>B</td><td>22nm/min</td><td>3.5Pa</td><td>135nm</td><td>3.5nm</td>

<td>C</td><td>36nm/min</td><td>5Pa</td><td>135nm</td><td>365nm</td>

<td>D</td><td>36nm part</td><td>5Pa</td><td>50nm</td><td>1.3nm</td>

That is, as the "deposition speed" and "total pressure" increase, the surface roughness Ra also increases. It can be seen from the surface photos in Figures 6 and 7, that the greater the surface finish, the larger the gap between the "particles".

As described in the following implementation examples, the deposition speed of the sample BD is increased by 10 times or faster than the past photocatalytic film formation examples using the reactive sputtering method.

In other words, the deposition rate is greatly increased compared with the past, and all parameters such as pressure and substrate temperature are adjusted to obtain a porous photocatalytic film. The film thicknesses of samples B to D are within the usual film thickness range as the photocatalytic film. Therefore, if the surface cleanliness Ra is greater than 1.3 nm, a porous film with a high-quality photocatalyst function will be obtained.

The surface roughness Ra of the sample D is smaller than that of the sample C under the same film forming conditions, because the film thickness is different. According to the data in Figure 9, the surface finish Ra is depicted by the normalization of the film thickness.

Figure 10 is a graph depicting the contact angle of the ratio of the surface roughness Ra of the samples A to D to the respective film thickness Ra/T.

02821432.3 From this figure, we can know that the Ra/T of sample A is about 0.0062, and the Ra/T of sample B-D is concentrated in the range of 0.026-0.027, divided into 2 groups. In the case of the former (sample A), the contact angle after invisible light irradiation is about 83 degrees or more; in the case of the latter (samples B~D), the contact angle after invisible light irradiation is 7 degrees ~9 degrees, sharply reduced.

For example, if the contact angle after being irradiated with invisible light for 1 hour is less than 30 degrees as the scope of the present invention, the ratio of the film thickness to the surface roughness, namely Ra/T, is preferably above 0.02. Similarly, if the contact angle is less than 10 degrees as the scope of the present invention, the ratio of the film thickness to the surface roughness, namely Ra/T, is preferably above 0.025.

That is to say, while the deposition speed in the present invention is greatly improved compared with the past, by adjusting the total pressure and substrate temperature, the density of the formed photocatalytic film is reduced, and the particles are finer, and the gaps between the particles are formed. Porous photocatalytic film. Therefore, it can be known that for such a porous photocatalytic film, if the surface roughness exceeds a predetermined value, the characteristics of the photocatalyst body will be greatly improved.

Moreover, it can be inferred that the reason why the photocatalytic effect is activated after the degree of porosity is increased is due to the porosity and the increase in the surface area of the photocatalytic film, and at the same time, the defects of the catalytic effect are appropriately improved near the particle surface.

Compared with the past, the present invention greatly accelerates the deposition speed and rapid film formation, so the film formation time is greatly shortened, which is the greatest advantage of the present invention. For example, when a photocatalyst body with a film thickness of 200 nin is formed into a film, the deposition time used to take 100 minutes (1 hour and 40 minutes), but now it is shortened to less than 10 minutes with the present invention. As a result, the yield of the photocatalytic film is drastically improved, and the cost is reduced.

Compared with the past, the present invention can form a film at a lower substrate temperature, so the requirements for the heat resistance of the substrate are greatly reduced. In other words, organic materials such as plastics with poor heat resistance that could not be used in the past can be used as substrates, which broadens the application range of the photocatalytic film.

Hereinafter, the film formation parameters and related conditions are listed to illustrate various characteristics of the photocatalytic film of the present invention.

Fig. 11 is a graph showing the X-ray diffraction pattern of the photocatalytic film of Sample C.

As shown in the figure, the deafness value is very high, TiO₂The diffraction peak of is very weak and very broad. In other words, the crystals are disordered, the crystal particles are fine and contain many defects.

02821432.3 Figure 12 is the diffraction pattern after data processing is performed on the diffraction pattern of Figure 11 to remove background noise. The diffraction pattern described here is related to the TiO with "anatase structure"₂Diffraction peaks correspond to high-order reflections.

Figure 13 is a graph obtained by performing the same X-ray diffraction pattern measurement on the photocatalytic film of Sample A and removing the background noise.

As shown in Figure 13, although the Ti()2 diffraction peak of the anatase structure is obtained, the height of the reflection peak appears different from Figure 12 (Sample C). Specifically, compared with the comparison table of the diffraction peak intensity corresponding to the anatase (101) diffraction peak that appears when the diffraction angle is about 25 degrees, and the sample C (Figure 12), the main peak in sample A (Figure 13) The relative strength is higher.

The intensity ratios of other main diffraction peaks and (101) diffraction peaks are as follows:

<td>Intensity ratio of diffraction peaks</td><td>Sample A</td><td>Sample C</td>

<td>(101) / (112)</td><td>10.4</td><td>3.8</td>

<td>(101) / ( 200 )</td><td>7.5</td><td>3.7</td>

<td>(101) / (105)</td><td>6.3</td><td>/ 2.2</td>

<td>(101) / ( 204 )</td><td>10.7</td><td>3.9</td>

<td>(101) / (215)</td><td>&gt;300</td><td>9.6</td>

<td>From the above intensity ratio, it can be known that</td><td>Sample A</td><td>(101) The intensity ratio of diffraction peaks is very</td>

High, the same film structure as the [110] direction is obtained. In contrast, the intensity ratio of the (101) diffraction peak in sample C is very low. That is to say, the homotropy in sample C is very low, and a majority of crystal sets with random orientation relationships are formed.

Even from the X-ray diffraction data, the present invention uses a faster, high-pressure, and low-temperature deposition of the photocatalytic film than in the past, forming a porous film with many gaps. It is precisely because of this unique porous structure that dramatically improves the role of the photocatalyst body.

From the results of the paraffin decomposition hydrophilic test (Figure 9 and Figure 10), as the photocatalytic film of the present invention, the intensity ratio of the (112) diffraction peak to the (101) diffraction peak is about 5 or less, or (105) ) The intensity ratio of the diffraction peak to the (101) diffraction peak is about 4 or less, and the intensity ratio of the (215) diffraction peak to the (101) diffraction peak is about 100 or less.

Next, the film quality dependence on the total pressure during sputtering will be explained.

02821432.3 The DC power supply during sputtering was set at 2kW, the oxygen partial pressure was fixed at 30%, a titanium oxide film was deposited, and the refractive index and density ratio were measured. The result is as follows:

<td>All pressure</td><td>Refractive index Ν</td><td>Density ratio</td>

<td>IPa</td><td>2.73</td><td>1</td>

<td>2Pa</td><td>2.69</td><td>0.94</td>

<td>3Pa</td><td>2.63</td><td>0.88</td>

<td>5Pa</td><td>2.3</td><td>0.829</td>

An ammonia atmosphere (He-Ne) laser polarization ellipsometer is used to measure the above refractive index. Moreover, the effective medium approximation method of the spectroscopic polarized light ellipticity meter is used to evaluate the density ratio.

Figure 14 is a graph depicting the refractive index and density ratio under all pressures.

It can be seen from this graph that if the total pressure during film formation is increased, the refractive index and density will gradually decrease. This is because as the total pressure increases, the porous photocatalytic film will become rougher accordingly.

In addition, the composition and absolute value of the density of the photocatalytic film of sample B (formed at a total pressure of 3.5 Pa) were measured by the Rupifer backscattering analysis method (RBS). The measurement conditions are as follows:

<td>Energy decomposition ability</td><td>24keV</td>

<td>Incident energy</td><td>2.0 MeV</td>

<td>Angle of incidence</td><td>0 degree</td>

<td>Incident ion</td><td>4He⁺</td>

<td>Incident beam diameter</td><td>1.0mm</td>

<td>Test current</td><td>ΙΟηΑ</td>

<td colspan="2">The RBS measurement results of sample B are as follows:</td>

<td>O/Ti</td><td>2.02</td>

<td>density</td><td>4.45g/cm³</td>

<td colspan="2">Here, the measurement accuracy of O/Ti value is about ±5%, and the measurement accuracy of density is also ±5%</td>

about.

In the present invention, since Sample B is porous and has a low-density photocatalytic film formed, the above-mentioned excellent photocatalytic body characteristics are obtained. In other words, from the above measurement results

02821432.3 It can be known that in the present invention, if the density of the photocatalyst body is less than 4.45g/cm³At this time, a porous photocatalytic film with excellent photocatalytic effect will be achieved.

Next, the relationship between the film formation conditions during sputtering and the characteristics of the photocatalytic film will be explained. The inventors used the DC sputtering device in Fig. 4 to change various reactive sputtering conditions to form a photocatalytic film and study its characteristics.

Fig. 15 is a list of the photocatalytic film forming conditions of the implementation examples by the present inventors using the DC sputtering method.

Figure 16 is also a list of the photocatalytic film forming conditions of the comparative example by the present inventors using the DC sputtering method.

In other words, here the "oxygen partial pressure (%)", "total pressure (Pa)", "film formation speed (nm/sec), "temperature (°C)", and "film thickness (nm) during sputtering ) as a parameter to study the relationship with the characteristics of the obtained photocatalytic film.

The temperature during sputtering refers to the average temperature during the sputtering process when the substrate is heated in the preparation chamber before being transported to the sputtering chamber. The carrier gas during sputtering is hydrogen (Ar) ο Using the paraffin decomposition hydrophilic test as the evaluation method of the photocatalytic film, the contact angle of the water droplets after being irradiated with invisible light with an intensity of 500p\V/cm2 for 1 hour is 10 degrees The following are qualified, and more than 10 degrees is considered unqualified.

First, the effect of oxygen partial pressure on the photocatalytic film during sputtering will be explained.

Fig. 17 is a graph showing the relationship between the oxygen partial pressure during sputtering and the contact angle of the obtained photocatalytic film. The horizontal axis of the graph represents the oxygen partial pressure during reactive sputtering, and the vertical axis represents the contact angle of water droplets after being irradiated with invisible light (500|iW/cm2) for 1 hour in the paraffin decomposition hydrophilicity test.

All the samples depicted in Figure 17 are under the condition that the total pressure during sputtering is 5 Pa, the DC input power is 2kW, the film formation speed is 0.3nm/sec, and the temperature is 330°C. The film thickness is 50nm. Deposited.

It can be seen from Figure 17 that the oxygen partial pressure during sputtering is in the range of 10% to 30%, the contact angle is very small, and a very good photocatalytic effect is obtained. In contrast, if the oxygen partial pressure is too low or too high, the contact angle will increase.

This is because if the gas partial pressure during sputtering is too low or too high, the oxygen in the resulting photocatalytic film is not within the normal composition range, or the combination of metal elements and oxygen is unstable

02821432.3 First decision.

In addition, the inventors found through observation that when the oxygen partial pressure is 30% or less, the formed photocatalytic film is opaque, and is in an opaque state with a metallic color. This is because the oxygen partial pressure is too low, and the resulting photocatalytic film has insufficient oxygen content.

On the contrary, if the oxygen partial pressure during sputtering is in the range of 10% to 30%, the resulting photocatalytic film will be transparent, and good properties of the photocatalyst body can be maintained. This is because the oxygen in the photocatalytic film is within the normal composition range, and the combination of metal elements and oxygen is stable. The electron-hole pairs excited in the film after light irradiation have a long life span, and the photocatalytic effect is reduced. activation.

Next, the influence of the total pressure during sputtering on the photocatalyst body will be explained.

Fig. 18 is a graph showing the relationship between the total pressure during sputtering and the contact angle of the obtained photocatalytic film. The horizontal axis of the graph represents the total pressure during reactive sputtering, and the vertical axis represents the contact angle of the water droplets after being irradiated with invisible light (GOOjiWcn) in the paraffin decomposition hydrophilic test for seven hours.

All the samples depicted in Figure 18 are deposited under the conditions of a sputtering oxygen partial pressure of 30%, a film formation rate of 0.3 to 0.6 nm/sec, and a temperature of 330 °C. The film thickness is 50 nm. Into.

It can be seen from Figure 18 that the total pressure during sputtering is 2Pa, and the contact angle of water droplets is about 14 degrees, but if the total pressure is 3Pa, the contact angle will drop to 4 degrees, and a very good photocatalytic effect is obtained. This is because if the total pressure of Gao is too low, the actual oxygen supply will decrease, and the film quality of the photocatalytic film will no longer be "porous" as shown in Figures 2 and 3.

On the other hand, if the total pressure is 5 Pa, the contact angle of water droplets is about 4 degrees, but if the total pressure is 6 Pa, the contact angle will quickly rise to 86 degrees. This is because if the overall pressure is too high, the film quality of the photocatalytic film, the bonding state of the metal element and the oxygen will change.

The above results show that the total pressure during sputtering is between 3 Pa and 5 Pa, and good photocatalyst characteristics will be obtained.

Next, the influence of the film formation speed during sputtering on the photocatalytic film will be described.

Figure 19 shows the relationship between the film formation rate during sputtering and the contact angle of the obtained photocatalytic film.

02821432.3 First series chart. The horizontal axis of the graph represents the film formation rate in reactive sputtering, and the vertical axis represents the contact angle of water droplets after being irradiated with invisible light (500uW/cin2) for 1 hour in the paraffin decomposition hydrophilicity test.

All samples depicted in Figure 19 are deposited under the conditions of sputtering with an oxygen partial pressure of 30%, a total pressure of 3 Pa to 5 Pa, and a temperature of 330°C. The film thickness is 40 nm to 100 nm. Accumulated.

It can be seen from Figure 19 that when the film formation speed is within the range of 0.2 to 0.6 nm/sec, the contact angle of the water droplet is below 10 degrees, and excellent photocatalysis is obtained. If the film formation speed increases to 0.7nm/sec, the contact angle will increase to 17 degrees. This is because if the film formation speed is too fast, the film quality of the photocatalytic film and the bonding state of the metal element and oxygen will be lowered.

The above results indicate that the film formation speed is preferably in the range of 0.2 to 0.6 nm/sec.

On the other hand, the film-forming speed has a great influence on the "yield". For example, if a 50nm photocatalytic film is deposited, the film formation speed is set to 0.2um/sec, and the time required for film formation is 250 seconds (more than 4 minutes). In contrast, setting the film formation speed to 0.4 nm/sec reduces the time required for film formation by half, that is, 125 seconds (approximately 2 minutes). Therefore, from a production point of view, the film formation speed is preferably faster, preferably 0.4 nm/sec or more.

Next, the influence of the temperature during sputtering on the photocatalytic film will be explained.

The inventors studied the relationship between "temperature" and "film formation speed" during sputtering. From the data in the table of Figs. 15 and 16, it can be known that the effect is "acceptable", that is, invisible light irradiation The contact angle of the water droplets after 1 hour is below 10 degrees. The following approximate formula is derived to show the relationship between the "temperature T" and the "film formation rate R" during sputtering.

R^2.36exp(-410(l/T)) (1) For the film formation rate R, the "temperature T" satisfies the conditions within the range of the above formula, and when the photocatalytic film is sputtered, a "qualified" photocatalyst body can be obtained characteristic. The relational expression of (1) above can be qualitatively explained for the following reasons.

During reactive sputtering, the metal elements sputtered on the target and oxygen molecules in the gas fly toward and are adsorbed on the deposition surface of the substrate. These elements migrate (move). After reaching the deposition surface, they are combined and fixed in a predetermined grid position. Part of the energy necessary for these metal elements and oxygen to migrate to the deposition surface is supplied by the heating of the substrate.

02821432.3 When the first film formation speed is very high, the supply speed of metal elements and oxygen flying to the deposition surface increases. Before the surface fully migrates, it is likely to be in an incompletely bonded state and be fixed in an unstable position. Therefore, by increasing the temperature of the substrate and promoting the migration of the surface, it becomes a suitable bonding state and is fixed in a stable position. When the film formation speed is high, it is better to increase the temperature T of the substrate.

In the present invention, by setting the temperature to satisfy the range of the above formula (1), a photocatalytic film having an excellent photocatalytic effect can be obtained.

Next, the influence of the film thickness on the photocatalytic film is explained.

Figure 20 is a graph showing the relationship between the film thickness of the photocatalytic film formed by sputtering and the contact angle. The horizontal axis of the graph represents the film thickness during reactive sputtering, and the vertical axis represents the contact angle of water droplets after being irradiated with invisible light (GOOpW/cn?) in the paraffin decomposition hydrophilic test for 1 hour.

All samples depicted in Figure 20 have an oxygen partial pressure of 30% during sputtering, a total pressure of 3 Pa to 5 Pa, a temperature of 330°C, and a film formation rate of 0.34 to 0.4 nm/sec. Under the conditions of deposition.

It can be seen from Figure 20 that when the film thickness is 20 nm, the contact angle is about 65 degrees, which is very large; when the film thickness is 30 nm, the contact angle will drop to 18 degrees. When the film thickness is increased to 40 nm, the contact angle will drop to 6 degrees, and a good photocatalytic effect is obtained. On the other hand, when the upper limit of the film thickness in the evaluation range is 170 nm, a good photocatalytic effect can be obtained. In other words, the film thickness is preferably 40 nm or more.

After studying the "decomposition effect and the "hydrophilic effect" of the photocatalytic film, the inventors conducted a "wet decomposition performance test" in order to study the relationship between the "decomposition effect" and the film thickness. Methylene blue ( C16H18N3S-C1) is used as a decomposed pigment. Methylene blue is a green organic pigment, which basically does not decompose after being irradiated by ultraviolet rays. Due to the decomposition activity of the photocatalyst body, it will irreversibly decompose and become colorless, which can be used for photocatalytic film. Decomposable evaluation.

Figure 21 is a flowchart showing the procedure of the wet decomposition performance test.

First of all, as shown in step S1, use purified water, surfactants and even ultrasonic purification as needed to clean the test product of the vaporized titanium film. Irradiate the cleaned test product with an invisible fluorescent lamp with a wavelength of 360nm and an intensity of lmW/cm2 or more for more than 24 hours, and then use the photocatalyst body to decompose the remaining organic pollution on the surface after cleaning.

02821432.3 Next, as shown in step S2, methine blue is saturated and adsorbed on the surface of the test product. That is to say, in order to use the adsorption of methine blue on the surface of the test product to offset the changes in the spectrum, the first is to use methine blue to adsorb on the surface before reaching the saturation level. The concentration of methine blue used as the adsorption solution is 0.02 mmol/l. After the test product is in contact with the new adsorption solution for 12 hours, the absorbance of the adsorption solution will decrease and the adsorption will be repeated.

In this way, methine blue is adsorbed on the surface of the test product, and after reaching a saturated state, the initial absorption spectrum is measured in step S3. At this time, the concentration of methine blue test solution is 0.01mmol/l.

In step S4, the spectrum after light irradiation is measured. In other words, fill the cup with the methine blue test solution, and then make it contact with the surface of the test product, and irradiate lmW/cm²20 minutes of UV light. Immediately after light irradiation, the absorption spectrum of the methine blue test solution was measured. Then, the measured test solution was quickly poured back into the cup, brought into contact with the surface of the test product, and irradiated with ultraviolet light for another 20 minutes.

In this way, the absorption spectrum of the methine blue test solution after ultraviolet irradiation was measured every 20 minutes, and the measurement was performed 9 times before the total irradiation time reached 3 hours. The higher the decomposition characteristics of the photocatalytic film, the more quickly the methine blue can be decomposed and decolorized. The light absorption characteristics are reduced.

Figure 22 is a graph showing the results of the wet decomposition performance test. The film thickness and the vertical axis of the photocatalytic film in the figure represent the decomposition activity index (nanomol/L/min) converted from absorbance.

It can be known from this figure that the decomposition activity index of the photocatalytic film increases with the increase of the film thickness, and after the film thickness reaches 100 nm, it is basically saturated. In other words, from the point of view of "decomposition", the decomposition characteristics of the photocatalytic film obtained by the sputtering method will reach a saturated state after the film thickness exceeds 100 nm.

In the paraffin decomposition hydrophilic test in Figure 20, when the film thickness of the photocatalytic film is less than 100nm, it has a good photocatalyst function. Therefore, within this film thickness range, the "hydrophilic characteristics" of the photocatalytic film will be reduced. Will make a difference.

On the other hand, the inventors have observed through observation that if the thickness of the photocatalytic film exceeds 80 nm, ghosts reflected by light may be visually observed. Therefore, from this point of view, the film thickness is preferably between 40 nm and 80 nm. Moreover, from the viewpoint of yield, the thinner the photocatalytic film, the better.

Next, the function of the "buffer layer" provided between the substrate and the photocatalytic film will be explained.

02821432.3 Figure 23 is a schematic diagram showing the cross-sectional structure of the photocatalyst body of the buffer layer.

A buffer layer 50 is provided on a predetermined substrate 100, and a photocatalytic film 10 is formed on the buffer layer. The material of the buffer layer 50 can be, for example, silicon oxide.

By providing such a buffer layer 50, it is possible to prevent impurities from mixing into the photocatalyst body from the substrate 100. Moreover, the surface texture of the substrate 100 is changed, and the initial stage of the deposition of the photocatalytic film 10 can be controlled in a more ideal state.

For example, when soda lime glass is selected as the substrate 100, alkaline elements such as sodium (Na) contained in the glass will diffuse into the photocatalytic film 10, reducing the characteristics of the photocatalyst body. In this case, by providing the buffer layer 50 made of silicon oxide or the like, the diffusion of impure substances is prevented, and the degradation of the photocatalytic properties is prevented.

Moreover, when the surface of the substrate 100 has microscopic irregularities, by providing a buffer layer 50 of an appropriate thickness, the surface irregularities can be alleviated, and the initial stage of the deposition of the photocatalytic film 10 can be closer to the ideal state.

The inventors selected soda lime glass as the substrate 100, silicon oxide as the buffer layer 50, and titanium oxide as the photocatalytic film 10 to study the effect of the buffer layer 50.

Figure 24 is a graph showing the results of the paraffin decomposition and hydrophilicity test.

That is, the horizontal axis of the graph represents the irradiation time of invisible light (500 pW/cm2), and the vertical axis represents the contact angle of the water droplet.

This figure shows the results of the photocatalyst bodies in which the thickness of the buffer layer 50 is 0 nm, 20 nm, 50 nm, 100 nm, and 260 nm, respectively. In addition, the photocatalytic film 10 of all samples was deposited by the reactive sputtering method, the oxygen partial pressure during sputtering was 30%, the total pressure was 5 Pa, the temperature was about 330°C, and the film formation speed was 0.5 nm. /Sec, the film thickness is 50nm.

It can be seen from Figure 24 that when the film thickness of the buffer layer 50 is in the range of 0-20 nm, the contact angle of the water droplets after being irradiated with invisible light for 1 hour is greater than 50 degrees. On the contrary, when the film thickness of the buffer layer 50 is 50 nm, the After 1 hour, the contact angle of the water droplet dropped to 14 degrees. Even when the film thickness of the buffer layer 50 is 100 nm, the contact angle after 1 hour of irradiation is 10 degrees, and when the film thickness of the buffer layer 50 is 260 nm, the contact angle after 1 hour of irradiation drops to 4 degrees.

Therefore, setting the buffer layer 50 to a certain thickness can improve the photocatalyst body

02821432.3 The first characteristic.

(Second Embodiment) / As the second embodiment of the present invention, a photocatalyst body in which a coating layer such as silicon oxide is deposited on a photocatalytic film having a photocatalytic action such as titanium oxide will be described below.

Fig. 25 is a schematic view showing a cross-sectional structure of a photocatalytic film according to a second embodiment of the present invention.

The photocatalyst body of this embodiment has a structure in which a photocatalyst film 10 is provided on a substrate 100, and a coating layer 20 is deposited thereon. Here, the photocatalytic film 10 is the same porous layer as the photocatalytic film 10 such as titanium oxide described in FIGS. 1 to 24. Furthermore, an oxide such as silicon oxide is selected as the coating layer 20.

The coating layer 20 moderately protects the surface of the photocatalytic film 10 within a range that does not affect the photocatalytic effect, and at the same time has the effect of maintaining hydrophilicity. In other words, under light conditions, as described in Figs. 1 to 24, the porous photocatalyst film 10 acts as an activating photocatalyst body, decomposes the attached matter, and maintains high hydrophilicity. However, in a state without light, the photocatalytic effect of the photocatalytic film 10 cannot be exerted. In contrast to this, the coating layer 20 maintains the hydrophilicity to achieve the effect of maintaining the surface and preventing the adhesion of contaminants.

Therefore, if the film thickness of the coating layer 20 is too thick, the photocatalytic effect of the photocatalytic film 10 will be hindered. On the contrary, if the film thickness of the coating layer 20 is too thin, the hydrophilicity will be insufficient.

Fig. 26 is a graph showing the results of the paraffin decomposition hydrophilicity test of the photocatalytic film having the layered structure of Fig. 25. Here, soda lime glass is used as the substrate 100. Furthermore, the sample D in the first embodiment and the titanium oxide film formed under the same conditions are selected as the photocatalytic film 10. On the other hand, the coating layer 20 deposited thereon is selected from silicon oxide. The photocatalytic film 10 is continuously deposited by a reactive sputtering method using a mixed gas of van (Ar) and oxygen (02). The DC input power is 300W, the total pressure is 3.5Pa, and the oxygen partial pressure is 30%.

Figure 26 depicts the data of five samples with the film thickness of the coating layer 20 being Onm, 3nm, 5nm, 7nm, and 14nm. It can be seen from this figure that, in the initial state contact angle before the invisible light is irradiated, all the samples provided with the coating layer 20 are smaller than the samples without the coating layer 20. That is, the coating layer 20 can improve the hydrophilicity of the surface.

On the contrary, after observing the contact angle irradiated by invisible light, if the coating layer 20 is

02821432.3 When the thickness of the first film is 3nm~7nm, it will be found that the sample (SiO₂The sample with a film thickness of Onm) and roughly the same paraffin decomposition characteristics, the photocatalysis is basically not hindered. Moreover, the intensity of the unusual light used here is 50μηι/«ιι²As described above, the strength is lower than that used in the general paraffin decomposition and hydrophilicity test, and the coating layer in the above-mentioned film thickness range will not substantially hinder the photocatalytic effect.

However, when the film thickness of the silicon oxide layer 20 is 14 nm, the decrease in the contact angle becomes smaller, and the effect of the photocatalyst body will be affected.

From the result of Fig. 26, it can be seen that the thickness of the coating layer 20 is preferably between 3 nm and 7 nm. Figures 27 to 29 are graphs showing the results of the paraffin decomposition hydrophilicity test of the photocatalytic film according to the second embodiment of the present invention. The photocatalytic film selected here is the same titanium oxide film as the sample D in the first embodiment as the photocatalytic film 10, and a silicon oxide film with a film thickness of 7 nm is selected as the coating layer 20.

Moreover, the sample data without the covering layer 20 was selected as the respective comparative examples.

Figure 27 shows the invisible light intensity of 500μιη/«ιι²According to the data at the time, under this irradiation intensity, the present embodiment provided with the coating layer 20 showed excellent hydrophilicity before and after irradiation.

Moreover, Figure 28 shows that the invisible light intensity is 50μπι/ειιι²According to the data under weak light, under this irradiation intensity, the photocatalytic film of this embodiment shows excellent hydrophilicity before irradiation, and after irradiation, the hydrophilicity is approximately the same as that of the comparative example.

On the other hand, Figure 29 is the data when the invisible light irradiation intensity is 10 μm/cm? ultra-weak light. Under this irradiation intensity, the photocatalytic film of this embodiment has shown excellent performance until 7 hours after irradiation. Hydrophilicity. This is because under the effect of ultra-weak light, the hydrophilicity of the coating layer 20 is stronger than the photocatalytic effect of the photocatalytic film 10.

As described above, according to this embodiment, if the light intensity is small before irradiation or when the light intensity is small, excellent hydrophilicity can be maintained.

Fig. 30 is a graph showing the change in contact angle when the photocatalytic film according to the second embodiment of the present invention is maintained in a dark place.

Here, the invisible light is irradiated first, and after the melting angle is close to 0, the light source is blocked and the dimension is measured

02821432.3 The result of the contact angle change in the dark place.

It can be seen from this figure that when the coating layer 20 is not provided, the contact angle increases in a relatively short period of time due to light blocking, and it increases to about 45 degrees after 8 days. On the other hand, in the sample of the present embodiment provided with the coating layer 20, the increase in the melting angle is very slow, and the thicker the coating layer 20 is, the more its rise is suppressed. That is, the thicker the film thickness of the coating layer 20, the stronger the maintaining hydrophilic property in the dark place.

As described above, according to this embodiment, by providing the coating layer 20 with a predetermined film thickness range on the photocatalytic film 10 such as titanium oxide, the photocatalytic action is not substantially hindered, and excellent dark space maintenance characteristics can be obtained. As a result, the surface hydrophilicity can be maintained at a high level no matter in the light state, or in the state where the light is weak or blocked.

Hereinafter, the embodiments of the present invention will be described in detail with reference to practical examples.

(First embodiment) First, as the first embodiment of the present invention, a photocatalyst body of the first embodiment of the present invention was produced, and compared with a comparative example produced by a conventional method.

Figure 31 is a graph showing the photocatalytic action of the photosilking agent of the present invention and the comparative example. The figure shows the results of the paraffin decomposition and hydrophilicity test. The invisible light intensity in Zhuangli is δΟΟμπι/οιη².

The photocatalyst body of the present invention shown here is the same as the above-mentioned sample D as the photocatalyst film of the first embodiment of the present invention. Moreover, the reactive sputtering method was used to make Comparative Example 1 and Comparative Example 2, and at the same time describe their characteristics.

The respective film forming conditions are summarized as follows.

<td></td><td>Sample D</td><td>Comparative example 1</td><td>Comparative example 2</td>

<td>Film forming method</td><td>DC sputtering</td><td>RF sputtering</td><td>RF sputtering</td>

<td>Input power</td><td>3kW</td><td>220 W</td><td>220 W</td>

<td>Deposition rate</td><td>36nm part</td><td>3.5nm/min</td><td>3.5nm/min</td>

<td>All pressure</td><td>5 Pa</td><td>2.7 Pa</td><td>2.7 Pa</td>

<td>Oxygen partial pressure</td><td>30%</td><td>.·^,τ11%</td><td>50%</td>

<td>Substrate temperature</td><td>280 °C below</td><td>300 Ό</td><td>400 Ό</td>

Because the above sample D was subjected to heating gas exhaust in the preparation chamber before sputtering deposition

02821432.3 In the first treatment, the initial temperature during deposition is higher than room temperature. The deposition is performed under the condition that the maximum temperature during the deposition does not exceed 280°C. Moreover, the background pressure of the vacuum chamber before the film formation of any of the above samples is reduced to 8x10⁴Pa below.

It can be seen from Fig. 31 that the contact angle before invisible light irradiation is 75 degrees in the present invention (Sample D), 85 degrees in Comparative Example 2, and 90 degrees in Comparative Example 2. After being irradiated with invisible light, the contact angle of the photocatalytic film of the present invention dropped sharply, and dropped to about 9 degrees after 1 hour. In contrast, the contact angles of Comparative Example 1 and Comparative Example 2 were 36 degrees and 51 degrees, respectively. Therefore, the photocatalytic film of the present invention exhibits a remarkable photocatalytic effect compared with the photocatalytic film made by the sputtering method in the past.

Moreover, the surfaces of Comparative Example 1 and Comparative Example 2 consist of particles that are 10 times as large as in Fig. 6(a) and Fig. 7(b) in a dense aggregate state, rather than porous.

Next, the X-ray diffraction pattern is measured.

Figure 32 is a graph showing the X-ray diffraction pattern of sample D.

Figure 33 is a graph showing the X-ray diffraction pattern of Comparative Example 1.

The diffraction peak in the figure corresponds to the diffraction peak of ΤΚ2 of the "anatase structure".

After comparing Figure 32 (Sample D) and Figure 33 (Comparative Example 1), the intensity of the diffraction peaks corresponding to the background level and the comparison table between peaks are quite different regardless of whether they are measured under the same conditions. That is, in Comparative Example 1 (Figure 33), the intensity of the diffraction peak is very large compared to the background intensity, and sharp and powerful diffraction peaks appear. Except for the low-dimensional (101) and (200) diffraction peaks, there are almost no diffraction peaks.

In contrast, in the sample C of the present invention (Figure 32), the intensity of the diffraction peaks corresponding to the background level is relatively low, and weak diffraction peaks are obtained. Moreover, many high-dimensional diffraction peaks appear.

After studying the comparison table of the intensity of other diffraction peaks corresponding to the (101) diffraction peak of anatase, in the case of Comparative Example 1 (Figure 32), the intensity of the (101) and (200) diffraction peaks are overwhelmingly high , Obtained a strong directional structure in the low-dimensional orientation.

On the contrary, in the case of sample D (the 32nd Yu) of the present invention, the intensity comparison table of the (101) diffraction peak is very low, and many high-dimensional diffraction peaks can be observed. In other words, it is presumed that there are many turbulent crystal flows with low orientation in the sample D of the present invention.

02821432.3 The ratio of the intensity of the other main diffraction peak to the intensity of the (101) diffraction peak is as follows: The intensity of the diffraction peak is compared to sample D. Comparative example 1 (101) / (112) 3.7 &gt;1000 (101)/ (105) 6.3 -270 Understanding the above After the intensity ratio, the (101) diffraction peak intensity ratio in Comparative Example 1 is all high, and a strong oriented film structure is obtained. In contrast, in sample D, the (101) diffraction peak intensity ratio is very low.

In other words, it can be seen from the results that the photocatalytic film of Comparative Example 1 has very good crystallinity, while the sample D of the present invention is porous and contains many fine particle aggregates composed of crystal defects.

After comparing the film forming conditions of the present invention and the comparative example, the deposition speed of the present invention is more than 10 times faster, the overall pressure is high, and the substrate temperature is low. In other words, these comparative examples formed films under the conditions of high temperature, low pressure, and low speed. Generally speaking, after the film is deposited at high temperature and low speed, its crystallinity is good and the film texture is dense. This is also consistent with the surface structure and X-ray refraction results.

In this regard, compared with the past, the present invention greatly increases the deposition rate, forms a film under high pressure and low temperature, forms a unique porous photocatalytic film, and significantly improves the function of the photocatalyst body.

(Second embodiment) As a second embodiment of the present invention, the photocatalytic action of the photocatalyst body of the second embodiment of the present invention and the conventional photocatalyst body under the action of weak light will be compared and discussed.

First, the substance shown in Figure 25 was trial-produced as the photocatalyst body of the present invention. Here, soda lime glass is selected as the substrate 100, the buffer layer of silicon oxide is deposited with a thickness of 50nm, and the photocatalytic film 10 and the coating layer 20 are continuously deposited.

The photocatalytic film 10 is the same as the sample B described in the first embodiment. Furthermore, silicon oxide with a film thickness of 7 nm was deposited as the coating layer 20 by reactive sputtering.

On the other hand, a titanium oxide film with a film thickness of 100 nm was deposited on the same substrate and buffer layer using a vacuum evaporation method as Comparative Example 3, and then a silicon oxide film with a film thickness of 15 nm was deposited on the same substrate and buffer layer by a vacuum evaporation method. When depositing titanium oxide, select TizOs as the evaporation source, and input oxygen into the vacuum chamber to make the oxygen partial pressure reach 1.3xl2-2pa and evaporate electrons.

02821432.3 The first beam. The deposition rate of titanium oxide is 18nm/min, and the substrate temperature is 200°C.

When depositing silicon oxide, use SiO2 as the evaporation source, and input oxygen into the vacuum chamber to make the oxygen partial pressure reach 2.6x10 ²Pa, the deposition rate of the electron beam silicon oxide evaporated is 30nm/min, and the substrate temperature is 200°C.

Figure 34 is a graph showing the photocatalytic effects of the photocatalyst bodies of the present invention and the comparative example in comparison. This figure shows the result of the paraffin decomposition and hydrophilization test, where the intensity of the invisible light is 50μιη/«η²The faint light.

It can be seen from Fig. 34 that in the initial state, the contact angle of the present invention and the comparative example is about 17.4 degrees, but the descending speeds after invisible light irradiation are different. The contact angle of the photocatalyst body of the present invention dropped to 4 degrees after being irradiated for 1 hour, and in the case of Comparative Example 3, it was maintained at about 11 degrees.

Even if the photocatalyst body of the present invention is 50μιη/«η²Compared with the photocatalyst body with a laminated structure in the past, the photocatalytic effect is higher. This is because the photocatalytic effect of the photocatalytic film 10 is large, and the layer thickness of the coating layer 20 is set within an appropriate range.

(The third implementation example) Next, through the third implementation example of the present invention, the photocatalytic action of the photocatalyst body of the second embodiment of the present invention and the conventional photocatalyst body under the action of ultra-weak light will be compared and studied. .

In this embodiment, the substance shown in Figure 25 is trial-produced as the photocatalyst body of the present invention. Here, soda lime glass is selected as the substrate 100, a buffer layer of silicon oxide is deposited with a thickness of 50 nm, and the photocatalytic film 10 and the coating layer 20 are continuously deposited.

The photocatalytic film 10 is the same as the sample D described in the first embodiment. Furthermore, silicon oxide with a film thickness of 7 nm was deposited as the coating layer 20 by reactive sputtering.

On the other hand, the same sample as in the second implementation example was prepared as Comparative Example 3.

Figure 35 is a graph showing the photocatalytic effects of the photocatalyst bodies of the present invention and the comparative example in comparison. This figure shows the results of the paraffin decomposition and hydrophilization test, where the invisible light irradiation intensity is 10pm/cm² of ultra-weak light.

It can be seen from Figure 35 that in the sample of Comparative Example 3, even if the invisible light is irradiated, the melting angle does not decrease, but only slightly floats up and down. This shows that the lOjun/cn? is super weak

02821432.3 Under the action of the first light, almost no photocatalysis is produced.

On the contrary, in the sample of the present invention, after the invisible light is irradiated, although it is slow, the contact angle does decrease, resulting in a photocatalytic effect.

In other words, the photocatalyst body of the present invention can obtain a photocatalytic effect even under the action of ultra-weak light of 10 pm/cni'. Compared with the conventional photocatalyst body having a laminated structure, the photocatalytic effect is active. This is because the photocatalytic effect of the photocatalytic film 10 is large, and the layer thickness of the coating layer 20 is set within an appropriate range.

(Fourth embodiment) Through the fourth embodiment of the present invention, a suitable manufacturing device for producing the photocatalyst body of the present invention will be explained.

Fig. 36 is a conceptual diagram showing the configuration of important parts of the photocatalyst body manufacturing apparatus of the present invention. The figure (a) shows its planar structure, and the figure (b) shows its cross-sectional structure.

The manufacturing apparatus of this example is set above the main chamber 200 that can be evacuated, and includes SK) 2 film forming chamber 210, heating chamber 220, Ti() 2 film forming chamber 230, TiCh film forming chamber 240, Si ®Film forming chamber 250, road gate 260.

A transport table 400 is provided in the main chamber 200, and the substrate 100 is loaded on this transport table 400 and can be transported to the bottom of each chamber. As shown in FIG. 36(b), the substrate 100 is transported by the transport table 400 to the bottom of each chamber, and then transported by the elevator 600. For example, as shown in FIG. 36(b), after the substrate 100 is transported to the TiO 2 film forming chamber 230, the elevator 600 and the substrate holder 420 are simultaneously raised and transported to the space of the film forming chamber 230.

In the case of the manufacturing apparatus of this example, the substrates 100 introduced into the room from the gate 260 are sequentially transported by the transport table 400, the buffer layer 50 is formed in the SiO2 film forming chamber 210, and heated to a predetermined temperature in the heating chamber 220, A TK) 2 film (photocatalytic film) 10 with a predetermined film thickness is formed in the TiO2 film forming chambers 230 and 240, and then SiO is formed in the Si() 2 film forming chamber 250₂The covering layer 20 is finally taken out from the road gate 260.

In the heating chamber 220, for example, a lamp such as a quartz lamp is used to heat the substrate 100 to a predetermined temperature.

Figure 37 is a conceptual diagram of the important components of the Ti() 2 film forming chamber 230 (or 240). Set a titanium (Ti) target 102 in the film forming chamber, and pass the mass flow controller (MFC)

02821432.3 Section

600 and 610 can respectively input reactant gases such as hydrogen and oxygen.

The substrate holder 420 is not completely sealed in the film forming chamber 230, and an opening (not shown in the figure) may be appropriately provided therebetween. In other words, the inside of the film forming chamber 230 is exhausted using the vacuum exhaust system that communicates with the main chamber 200 through this opening.

A reactive gas containing oxygen, such as nitrogen and oxygen, is respectively input into the film forming chamber 230 through MFCs 600 and 610, and a target voltage is applied through a DC power supply 510 to perform reactive DC sputtering.

In this embodiment, the controller 500 can be used to control the actions of heating devices such as lamps installed in the heating chamber 220. Specifically, as shown in Figs. 15 and 16, when the film formation rate R and the substrate temperature T satisfy the following relational expressions, control can be implemented.

R^2.36exp(-410(l/T)) (1) For example, when a photocatalyst body is manufactured, a predetermined film forming speed is input to the controller 500. The controller 500 calculates the temperature range that satisfies the above formula (1) at this speed, determines the heating conditions in the heating chamber in advance, and performs preheating, so as to maintain this temperature range during film formation.

As shown in Figure 15 and Figure 16, in order to produce a good photocatalyst body, the total pressure is preferably between 3 Pascal and 5 Pascal, and the oxygen partial pressure is between 10% and 30%. Therefore, the above-mentioned conditions can be satisfied simultaneously by the controller 500 and the MFC 600 and 610.

The film formation speed is mainly determined by the input power of the DC power supply 510, but it is also affected by the total pressure and the partial pressure of oxygen. From this point, it is best to use the controller 500, MFC600.610 for control.

According to the input power of the DC power supply 510, the substrate temperature changes differently during film formation. In this regard, the controller 500 may be considered to control the heating device provided in the heating chamber 220.

The controller 500 can control the DC power supply 510. In other words, in order to obtain a predetermined film formation speed, the power input from the DC power supply 510 to the target can be controlled.

Instead of inputting the film formation speed after deciding in advance, it is better to decide the film formation temperature in advance. That is, the film forming temperature is specified in advance, and the film forming speed is calculated by the above-mentioned relational expression at this film forming temperature, and the controller 500 can control the DC power supply 510.

Moreover, it is not necessary to determine the film formation speed and film formation temperature in advance, the controller can control these,

02821432.3 The film is formed again. At this time, under the condition that the above-mentioned relational expression (1) is satisfied, the controller 500 determines the film formation speed and the film formation temperature, and performs film formation.

As described above, in this embodiment, the controller 500 appropriately controls the relationship between the substrate heating condition and the film forming speed, and a stable photocatalyst body with excellent photocatalytic properties and excellent reproducibility can be manufactured.

Fig. 38 is a conceptual diagram showing a modified example of the photocatalyst body medium manufacturing apparatus of the present invention. This figure shows the planar structure of the manufacturing apparatus. With the conveyor 700 as the center, a vertical Si() 2 film formation chamber 210, a heating chamber 220, a Ti() 2 film formation chamber 230, and ΤΚ) 2 are sequentially arranged around it. The film forming chamber 240, the SiO2 film forming chamber 250, and the gate 260.

The conveying device 700 has a bracket 720 that can carry a substrate, and is radial, and can be rotated in the direction of arrow A, or can be conveyed in the direction of arrow B.

Fig. 39 is a vertical cross-sectional view of the TK) 2 film forming chambers 230 and 240. The elements and symbols described in this figure are the same as those in figure 37, so detailed explanations are omitted.

The substrate 100 placed on the substrate holder 720 is rotated and transported to the front of the chamber by the transport device 700, and then transported to the direction of the chamber, and the holder 720 is used to form a sealed state in the chamber. In this state, the film forming chamber 230 (240) is evacuated using a turbo molecular pump (TMP) 110.

In the film forming chamber 230 (240), hydrogen and oxygen are input, and reactive sputtering is performed. At this time, as shown in FIG. 37, the film forming speed and the film forming temperature are controlled by the controller 500 to satisfy the above equation (1). For example, if the film formation speed is specified in advance, the controller 500 calculates that the substrate heating condition satisfying the above formula (1) at the film formation speed, and uses the controller 500 to control the operation of the heating device installed in the heating chamber 220 to heat the substrate. In the case of this modified example, the controller 500 not only controls the heating device, but also controls the DC power supply 510. At this time, the controller 500 controls the DC power supply 510 to perform Ti() 2 film formation.

As shown in Figure 15 and Figure 16, in order to produce a good photocatalyst body, the total pressure is preferably between 3 Pascal and 5 Pascal, and the oxygen partial pressure is between 10% and 30%. Therefore, the controller 500 performs control so as to satisfy the above-mentioned conditions at the same time.

The manufacturing apparatus of this modified embodiment, by appropriately controlling the relationship between the substrate heating condition and the film forming speed according to the controller 500, can be manufactured with good reproducibility, stability, and performance.

02821432.3 The photocatalyst body with the characteristics of the photocatalyst body of the second color.

In FIGS. 36 to 39, specific examples in which the substrate 100 is heated in advance in the heating chamber 220 provided in the film forming chamber are listed.

However, the present invention is not limited to these. For example, the present invention is also applicable to manufacturing devices in which the substrate heating device is installed in the film forming chambers 230 and 240, and the same effect can be obtained. In the case of such a manufacturing device, the controller 500 controls the substrate heating device to satisfy the above formula (1) before performing film formation.

The embodiment of the present invention has been described with reference to the above-mentioned specific examples. However, the present invention is not limited to these specific examples.

For example, the photocatalytic film of the present invention is not limited to titanium oxide (TiO₂), the same effect can be obtained by adding prescribed elements to titanium oxide, and these are included in the scope of the present invention.

When the photocatalytic film of the present invention is formed by sputtering, the reactant gas input into the chamber is not limited to hydrogen and oxygen, but can also be other gases, such as a mixed gas of gases other than ammonia and oxygen, or a mixed gas of gases other than nitrogen and oxygen. .

As described above, the present invention can provide a photocatalyst body with a better photocatalytic effect by forming a unique porous photocatalytic film that is different from the conventional one.

This catalyst medium not only does not reduce the photocatalytic effect by depositing silicon oxide with a prescribed film thickness, but also maintains a high level of hydrophilicity in the dark.

Since the present invention greatly increases the deposition speed and forms the photocatalytic film, it can greatly increase the output, improve the production performance, and greatly reduce the cost.

As the photocatalyst body coating of the present invention, the surface of the photocatalyst body of the present invention can be covered, for example, automobile rearview mirror, car body or window glass, and can also be used for various mirrors such as bathrooms, exterior wall materials for buildings, and bathrooms. Wall materials, toilets, drains, road signs, various signs, etc.

When used in the rearview mirror of a car, the photocatalytic film has the function of accelerating water flow and anti-fogging, which can obtain a clearer vision and ensure safety. In addition, when it is used for car bodies, road signs, and exterior wall materials for buildings, it can clean itself by rain.

In short, the present invention can improve a cheaper high-performance photocatalyst body, can be used in various covering material markets, and has obvious advantages in the industry.

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