JPH0972761A - Cover glass for instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel self-cleaning cover glass for instrument having contamination-proof function based on high fat and oil decomposing activity and high optical transparency. SOLUTION: The glass cover being fixed to an instrument is deposited, at least partially on the outer surface of a glass plate 1, with titanium oxide 2 exhibiting photocatalytic action. The titanium oxide 2 exhibits linear transmittance of 50% or above for the light having wavelength of 550nm, 50% or less for the light having wavelength of 350nm, and has the power for decomposing 0.5μg or more of linolic acid per 1cm<2> of titanium oxide per hour upon irradiation with UV-rays containing at least a part of light having wavelength in the range of 300-400nm at an intensity of 5mW/cm<2> . This composition realizes a novel self-cleaning cover glass for instrument having excellent fat and oil decomposing properties and exhibiting high transparency to visible light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover glass for measuring instruments used in various electronic devices and meters, electronic display devices and the like having an antifouling function based on an excellent oil and fat decomposing ability, and in particular, oil and fat contents such as hand dust and sebum. The present invention relates to a new instrument cover glass having a novel self-cleaning property, which is effective for disintegrating efficiently and sterilizing floating bacteria and molds attached thereto and antibacterial.

[0002]

2. Description of the Related Art In recent years, various coatings have been applied to instrument cover glasses and lenses used in various meters, measuring instruments and display devices for the purpose of preventing reflection. For example, taking an automobile instrument as an example, an attempt has been made to perform surface coating by a sputtering method or the like in order to prevent reflection of the cover glass and improve design. However, when handling or using such a cover glass, mist of sebum or organic matter such as fingers that is inevitably attached,
No effective one has been developed for contamination by airborne bacteria, especially for the attachment of mold, and a suitable solution has been found only for frequent cleaning with a wiping cloth or the like.

On the other hand, conventionally, attempts have been widely made to remove and decompose pollutants and the like in the air by utilizing a photocatalyst centered on titanium oxide (for example, JP-A-6-385 and JP-A-6-385). 6-49677, etc.).
In addition, it is 1 μm on the quartz glass substrate by RF sputtering method.
An attempt to attach a thin titanium oxide thin film to a photo-semiconductor electrode for hydrogen generation (see JP-A-60-44053),
Attempts have also been made to attach a titanium oxide film to the surface of an eyeglass lens by the ion plating method to decompose the surrounding malodorous components (see Japanese Patent Laid-Open No. 223909/1990).

[0004]

[Problems to be Solved by the Invention] The above-mentioned JP-A-2-223909
In the air purifying glasses described in the publication, although a titanium oxide thin film is provided on the instrument cover glass surface by a physical method such as an ion plating method, the identification of titanium oxide and the crystal structure of the thin film, the deodorizing effect of Almost no objective structure or data disclosure has been made regarding judgments.

In the prior art, in order to obtain a photocatalytic action of high practical level by forming titanium oxide into a thin film, titanium oxide sol is formed on a substrate by sintering, or fine powder of titanium oxide is applied and baked together with a binder. It was thought that there was no suitable method. However, in the former case, it is necessary to set the sintering temperature to a temperature higher than the glass softening point in order to obtain a film strength that can withstand practical use even if one having high activity and light transparency to some extent is obtained. It was difficult to apply it to commercial glass. Further, in the latter case, since it is a finely powdered titanium oxide, the light transmittance is extremely low, which is a fatal defect for a lens, and further, since the surface irregularities are severe, dirt and dust are likely to be attached.

An optical semiconductor thin film formed by a physical film forming method such as a sputtering method is disclosed in JP-A-60-44053, which is formed on a quartz substrate for generating hydrogen as an optical semiconductor. Thus, it is unsuitable for the photocatalyst thin film for the purpose of the present invention for decomposing oils and fats applied to the instrument cover glass. It is true that a quartz substrate can be used as a cover glass for instruments, although a thin titanium oxide thin film can be obtained with some activity. As described in the examples of the present invention, unless the precoat thin film layer according to the present invention is provided or the film thickness of the titanium oxide thin film is not provided, the instrument cover having a practical composition is used unless it is thickened. This is because high fat and oil decomposition activity cannot be obtained with glass.

The conventional glass with titanium oxide, which uses powder or sol, is substantially opaque and has low light transmittance. For example, in the case of an automobile instrument, a light source is installed in the instrument to emit light. It was difficult to reach the surface (titanium oxide layer) on the outer surface of the cover glass where pollutants in the atmosphere are most likely to adhere. Therefore, the light that can be used is limited to the weak light inside the vehicle, which is the light from the outside of the instrument.Therefore, the amount of light is much smaller than that with a transparent titanium oxide thin film, and the amount of decomposed pollutants is also small. On the other hand, there is a drawback that dirt and oil mist are easily attached due to the unevenness of the surface.

The present invention has been made under the above-mentioned background, and as a cover glass for various instruments, it is transparent to light in the visible light region, its surface is smooth and stain resistant, and its photocatalytic activity is high. The purpose of the present invention is to provide a new instrument cover glass having self-cleaning properties such that highly adhered oils and fats can be efficiently decomposed by light.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, a measuring instrument cover glass according to the present invention is (Structure 1) a measuring instrument cover glass which is attached to measuring instruments, and which is at least a measuring instrument of a glass plate. A titanium oxide thin film having a photocatalytic action is provided on at least a part of the surface arranged on the outer side when being attached to the titanium oxide thin film. Linear transmittance for 5
Ability to decompose linoleic acid to 0.5 μg or more per 1 cm ² of the titanium oxide thin film per hour when irradiated with ultraviolet light having an intensity of 5 mW / cm ² which is 0% or less and contains at least a part of light of 300 to 400 nm. And the film thickness of the titanium oxide thin film is 0.1 to 5 μm.
As a structure of the structure 1 or 2, the structure 3 is characterized in that the titanium oxide thin film contains at least anatase crystal, and the structure of any one of structures 1 to 3 As (Structure 4), the titanium oxide thin film contains at least one additive selected from the group consisting of silver, copper, and zinc in an amount of 0.05 to 5 atom% with respect to the titanium atom. As an aspect of any one of configurations 1 to 4, (configuration 5) is a configuration characterized in that a precoat thin film is provided between the glass plate and the titanium oxide thin film, and as an aspect of this configuration 5, (configuration 6) ) The thickness of the precoat thin film is 0.02 to 1 μm.
m is a constitution, and as a mode of constitution 5 or 6, (constitution 7) the precoat thin film is a thin film made of a material containing SiO ₂ as a main component.
As an aspect of any one of configurations 5 to 7, (configuration 8), at least one layer of the precoat thin film includes a thin film made of a material containing indium oxide and / or tin oxide as a main component, As an aspect of any one of Configurations 1 to 8, (Configuration 9) is characterized in that the glass plate is made of glass containing soda lime glass as a main component.

[0010]

According to the above-mentioned structure 1, the instrument cover glass is attached to the instrument, and has a photocatalytic oxidation on at least a part of the surface of the glass plate which is arranged on the outside when attached to the instrument. Providing a titanium thin film,
This titanium oxide thin film has a linear transmittance of 50% or more for light having a wavelength of 550 nm, and a linear transmittance of 50% or less for light of a wavelength of 350 nm.
Ultraviolet light including a part of light of ~ 400nm is 5mW / cm
A cover glass for various instruments, which is characterized in that it has a capability of decomposing linoleic acid at 0.5 μg / cm ² per 1 cm ² of the titanium oxide thin film when irradiated with an intensity of ^2. As the above, it is possible to extremely effectively absorb the light having a wavelength of 400 nm or less that induces the photocatalytic action while sufficiently securing the required light transmittance, and effectively decompose even the fat and oil component in an amount that adheres in a normal environment. It is possible to obtain an epoch-making self-cleaning performance. Of course, since it has the ability to decompose even fats and oils, which are generally said to be very difficult to decompose, it also has antibacterial and deodorizing functions. Therefore, when this instrument cover glass is used as, for example, instrument instrument cover glass for automobiles, various measuring instruments, or cover glass for analytical instruments, airborne bacteria, dust, etc. can be removed as well as conventionally. It was very difficult to remove these oils and fats such as hand deposits, organic mist and oils and fats that adhere when placed indoors or outdoors. Without adding
The epoch-making effect that the desired clean state can be automatically maintained can be obtained.

According to the constitution 2, the titanium oxide thin film having a film thickness of 0.1 to 5 μm has sufficient photocatalytic activity, and at the same time has a linear transmittance of 50% or more for light of a wavelength of 550 nm measured by the above-mentioned measuring method. The titanium oxide thin film it has can be easily obtained. If the film thickness is less than 0.1 μm, sufficient photocatalytic activity may not be obtained, and if the film thickness exceeds 5 μm, the film becomes cloudy and has a wavelength of 5 μm.
The linear transmittance for light of 50 nm is less than 50%, and there is a possibility that sufficient transparency may not be secured, which is not preferable.

According to the constitution 3, the titanium oxide thin film contains the anatase crystal, whereby the titanium oxide thin film can have a higher catalytic activity.

According to the structure 4, the titanium oxide thin film is provided with silver,
By adding at least one additive selected from the group consisting of copper and zinc in an amount of 0.05 to 5 atomic% with respect to the titanium atom, it is possible to improve the catalytic activity, particularly the antibacterial activity. These additives can be added by various addition methods, but as a method for uniformly adding a trace amount of additives, the photoreduction method by photocatalysis is the easiest and excellent in this case. As a result, for example, in the case of adding silver, there is an advantage that the antibacterial activity can be maintained high not only when light is irradiated but also when light is not irradiated, and in the case of copper, excellent antifungal property can be exhibited. In the case of adding zinc, there is an advantage, and the solid acidity of titanium oxide can be lowered so that even an acidic substance can be easily adsorbed on the surface, which is advantageous for their decomposition and removal. Further, since such an additive is often required to have a visible light transmissive property particularly as a cover glass for an instrument, it is indispensable to add a very small amount of this additive. The above-mentioned photoreduction method is also one of the most excellent methods in that respect, and the titanium oxide thin film according to the present invention serves its purpose.

According to the constitution 5, by providing the precoat thin film between the instrument cover glass and the titanium oxide thin film, a part of the components of the instrument cover glass diffuses and permeates into the titanium oxide thin film to form the titanium oxide thin film. It is possible to prevent adverse effects such as a decrease in photocatalytic action. Moreover, this has made it possible to expand the range of choices for the material of the instrument cover glass. Furthermore, when a titanium oxide thin film is formed directly on the instrument cover glass, even if the components in the instrument cover glass penetrate into the titanium oxide thin film, it does not reach titanium oxide that performs charge separation. It was necessary to increase the film thickness of titanium oxide in the above, but since it is no longer necessary, a sufficient photocatalytic action can be achieved even if the film thickness of the titanium oxide thin film is remarkably reduced regardless of the material of the instrument cover glass. It became possible to obtain. As a result, it is often the case that the glass plate used to set the desired refractive index according to the type and purpose of various instruments must have various compositions, but even if such composition changes are made, the activity is sufficiently high. It became possible to make a thin photocatalytic thin film.

As long as the thickness of the precoat thin film is 0.02 to 1 μm as in the constitution 6, even when considering general substances that can be adopted as the precoat thin film, sufficient transparency is ensured and the glass plate is removed. The effect of preventing the permeation of the inhibitory substance can be obtained. On the contrary, if the thickness is less than 0.02 μm, a sufficient permeation-inhibiting effect cannot be obtained, and even if a film having a thickness exceeding 1.0 μm is formed, the permeation-inhibiting effect does not have any further advantage. Is complicated, and transparency may not be secured depending on the material, which is not preferable.

When the precoat thin film is usually formed on the glass plate as the substrate by using a material containing SiO ₂ as a main component as in the constitution 7, the best transparency and the substance permeation prevention effect can be secured.

In addition, since an instrument using a cover glass usually has sophisticated electronic equipment in many cases, if a conductive thin film is provided on the surface of the cover glass as in the constitution 8, noise from the outside will be generated. Also, it is possible to protect the circuit by preventing malfunction due to electromagnetic waves.

As in Structure 9, as the material of these instrument cover glasses, soda lime glass which is commonly used can be used, and relatively inexpensive cover glass can be manufactured. .

[0019]

[Embodiment]

<Embodiment 1> FIG. 1 is a sectional view of an instrument cover glass according to Embodiment 1 of the present invention. Hereinafter, the instrument cover glass of Example 1 will be described with reference to FIG.

In FIG. 1, the instrument cover glass of this embodiment comprises a glass plate 1 made of soda lime glass and a titanium oxide thin film 2 formed on the surface thereof. The titanium oxide thin film 2 is a titanium oxide thin film containing anatase crystal and having a thickness of 4.4 μm. This instrument cover glass was prepared as follows.

First, the diameter 120 made of soda lime glass
mm glass plate 1 having a thickness of 2 mm is set in a pyrosol film forming apparatus, and titanium tetraisopropoxide 0.5 mo is prepared.
A raw material solution prepared by dissolving 1 l in 1 L of acetylacetone was ultrasonically atomized and introduced into the above apparatus at 20 ml / min to form a film at 500 ° C. for 60 minutes. As a result, the titanium oxide thin film 2 was uniformly formed on the surface of the glass plate 1. By observing the fracture surface with a scanning electron microscope (SEM), it was confirmed that the titanium oxide thin film 2 having a film thickness of 4.4 μm was formed on the glass plate 1. When the thin film on this cover glass was observed by thin film X-ray diffraction analysis, it was a titanium oxide crystal containing anatase crystal.

Then, the cover glass having the titanium oxide photocatalyst thin film thus obtained was measured for the harmful substance decomposing ability as an index of photocatalytic activity and the light linear transmittance as an index of transparency by the following method.

Method for Measuring Decomposition Ability of Hazardous Substances Decomposition activity of fats and oils was measured as an index of decomposability of harmful substances, and as a representative example, the decomposition activity of salad oil containing linoleic acid as a main component was investigated. On the surface of the titanium oxide thin film 2 on the cover glass having a diameter of 120 mm, a thin paper was applied to the surface of the titanium oxide thin film 2 so that the film thickness was 0.1 to 0.15 mg / cm ² .
The coating amount was determined by measuring the weight before and after coating. A high pressure mercury lamp was installed so that the surface of the cover glass was 5 mW / cm ^2, and after irradiation, the weight of the cover glass at a given time was measured with a precision balance to determine the relationship between the elapsed time and the amount of change in weight. And

Measurement of linear light transmittance A cover glass having a titanium oxide thin film was attached to a light transmittance measuring cell to prepare a cover glass having the same composition but not having a titanium oxide thin film. With one side being the sample side and the other side being the reference side, the linear transmittance for light of wavelengths of 550 nm and 365 nm was measured by a Shimadzu UV-3100PC spectrophotometer.

The result of the measurement by the above-mentioned method is that the salad oil decomposition activity is 11.5 μg / Hr · cm ² , the wavelength is 550 nm.
The linear transmittance with respect to the light of 65% and the linear transmittance with respect to the light having a wavelength of 365 nm were 12%, and it was confirmed that it has excellent fat and oil decomposition activity and sufficient transparency.

Further, from the other surface (rear surface) of the container in which the cover glass having the titanium oxide thin film 2 is placed on one surface of the glass plate 1, a black light FL1 which is an ultraviolet lamp.
3 mW / cm ² on the surface on which the titanium oxide thin film was attached by irradiating light with 0BLB (trade name of Toshiba Lighting & Technology Co., Ltd.)
When the salad oil-decomposing activity was similarly examined by adjusting the light irradiation intensity to 1), it was confirmed that a salad oil-decomposing activity of 6.5 μg / Hr · cm ² was obtained. This indicates that in the case of the cover glass of the present invention in which the titanium oxide photocatalyst film is attached to the glass plate, not only the light from the surface on the side where the titanium oxide thin film is provided, but also the light from the back surface can be sufficiently utilized. (In this embodiment, a black light is incorporated inside the measuring device to prevent contamination on the outside of the cover glass of the measuring device).

<Examples 2 to 4> Except that the thickness of the titanium oxide thin film was changed in the same manner as in Example 1, it had the same structure as in Example 1 and was manufactured by the same method. The film thickness, salad oil decomposing activity measurement result and light linear transmittance measurement result of each example are listed in the table of FIG. 3 and the detailed description thereof is omitted.

As shown in the table of FIG. 3, it can be seen that each Example has excellent salad oil degrading activity and sufficient transparency.

Example 5 In this example, silver is added to the titanium oxide thin film 2 of Example 1. A cover glass having a diameter of 120 mm was attached in the same manner as in Example 1 until a titanium oxide thin film had a thickness of 3.6 μm and a width of 15 c.
m, length 15 cm, depth 1 cm into a glass container, 1
% 50% aqueous silver nitrate solution was added, a 400 W high-pressure mercury lamp was irradiated for 10 minutes, and ultraviolet light was irradiated for 40 minutes to deposit a small amount of metallic silver on the titanium oxide thin film by photoreduction.
The amount of deposited silver was determined by the SEM-EDS method, and the results of measuring the salad oil decomposing activity and the results of measuring the linear light transmittance are summarized in the table of FIG.

As shown in the table of FIG. 3, it can be seen that each Example has excellent salad oil degrading activity and sufficient transparency.

<Examples 6 to 8> These examples are shown in FIG.
As shown in FIG. 3, a precoat thin film made of a SiO ₂ film was formed by dip coating between the titanium oxide thin film 2 and the cover glass 1 in the first embodiment.
It has the same structure as the above and is manufactured by the same method.
The thickness of the precoat thin film and the titanium oxide thin film of each example,
In addition, the measurement result of the activity for decomposing salad oil and the measurement result of the linear light transmittance are listed in FIG. 3 and the detailed description thereof is omitted.

As shown in the table of FIG. 3, as compared with Examples 1 to 4 in which the pre-coated thin film layer was not used, even if the titanium oxide thin film was thinned, excellent salad oil decomposing activity was exhibited, and therefore higher transparency was obtained. It turns out that you can secure.

<Embodiment 9> This embodiment has the same structure as that of Embodiment 6, and a precoat thin film 3 made of a SiO ₂ film having a thickness of 0.05 μm is formed on the glass plate 1 by dip coating. Further, the titanium oxide thin film 2 is formed on the same by dip coating. The cover glass with the pre-coated thin film 3 was immersed in a raw material solution prepared by dissolving 0.5 mol of titanium tetraisopropoxide in 1 L of acetylacetone, slowly pulled up at a pulling rate of 0.5 cm / sec, dried at room temperature, and baked at 400 ° C. This operation was repeated 13 times to form a titanium oxide thin film having a thickness of 1.4 μm. The results of the salad oil degrading activity and the results of the linear light transmittance measurement are shown in the table of FIG. 3, and the detailed description thereof is omitted.

As shown in the table of FIG. 3, it can be seen that excellent salad oil decomposing activity and linear light transmittance are exhibited.

<Embodiment 10> In this embodiment, as shown in FIG. 4, a precoat thin film 3 made of a SiO ₂ film is formed on a glass plate 1 by dip coating in the same manner as in Embodiments 6 to 8. Then, the pre-coated thin film 3
A second precoat thin film, which is a precoat thin film 4 made of an indium oxide thin film (ITO film) containing 8% tin oxide, is formed thereon to a film thickness of 0.2 μm by the pyrosol device, and then the same as in Example 1. The titanium oxide thin film 2 is provided by the method, and the film thickness of the pre-coated thin film and the fat and oil decomposition activity measurement result and the light linear transmittance measurement result are listed in a table in FIG. 3 and the detailed description thereof is omitted. To do.

As can be seen from the table of FIG.
Similar to the case of 8, a thin film having a higher salad oil decomposing activity than that of the titanium oxide thin film having no precoat layer was obtained. In addition, in the case of Example 10, since the transparent conductive film was pre-coated, the electromagnetic waves passing through the glass body were weakened, and the adhesion of dust due to static electricity was reduced.

Comparative Example 1 Diameter 12 used in Example 1
By the same method as in Example 1 using a cover glass of 0 mm, a titanium oxide thin film having a thickness of 0.05 μm was attached to the surface of the cover glass, and in the same manner as in Example 1, salad oil decomposition activity, visible light linear transmittance, The ultraviolet linear transmittance was measured.
The measurement results are listed in a table in FIG. 3 and the detailed description thereof is omitted.

As shown in the table of FIG. 3, in this comparative example, the transparency in the visible light region is good, but the photocatalytically active salad oil decomposing ability is very low.

[0039] In the same manner as <Comparative Example 2> Example 6, the film thickness of SiO ₂ on the surface of a glass plate having a diameter of 120 mm 0.
A 1 μm pre-coated thin film was applied by a dip coating method, and then the same method as in Example 6 was applied to a film thickness of 5.5 μm.
The same method as in Example 1 was used to measure the salad oil degrading activity, visible light linear transmittance, and ultraviolet linear transmittance. The measurement results are listed in a table in FIG. 3 and the detailed description thereof is omitted.

As shown in the table of FIG. 3, in this comparative example, although the activity of decomposing salad oil was excellent, the linear transmittance of visible light was as low as 45% and the glass surface was cloudy. .

As the glass plate used for the instrument cover glass of the present invention, glass for physics and chemistry equipment such as borosilicate glass can be used, but it is a glass used for ordinary plate glass or window glass. However, there is no particular limitation regarding the material.

When the cover glass of the substrate is soda lime glass or the like, the salad oil decomposing activity of the titanium oxide thin film is inhibited by an alkaline component such as sodium that diffuses from the substrate. It is desirable to provide a pre-coated thin film on. As a result, it is possible to advantageously use inexpensive glass such as soda lime glass in which alkali components may diffuse.

The titanium oxide thin film has a thickness of 0.1 μm to 5 μm.
If it is less than 0.1 μm, it is transparent but its activity is low, so that it is not practical, and if it exceeds 5 μm, the activity can be maintained high and coloring due to light interference is reduced, but the film is However, defects such as peeling of the film and a long film forming time tend to occur.

Further, the film thickness of titanium oxide to be formed is made large, for example, 0.3 μm to 5 μm, the sodium concentration in the titanium oxide thin film is gradually decreased, and titanium oxide in the vicinity of the thin film surface is utilized as a photocatalyst. It is also possible, in which case the pre-coated thin film can be omitted.

The precoat thin film has a thickness of 0.02 μm to 1 μm.
If it is less than 0.02 μm, the ability to prevent alkali diffusion is low, and if it exceeds 1 μm, the ability to prevent alkali diffusion is not hindered, but the light transmittance is lowered and the film forming conditions are complicated, which is not preferable. By providing a pre-coated thin film, it is possible to prevent the diffusion of alkaline components such as sodium from the substrate, so that it is possible to reduce the thickness of the titanium oxide thin film and obtain a cover glass for instruments that is more transparent in the visible light region. You can

The composition of the pre-coated thin film is not limited as long as it has a high visible light transmittance and can suppress the diffusion of sodium from the substrate. For example, a SiO ₂ thin film, a tin oxide thin film, an indium-added tin oxide thin film, an oxide Indium thin film, tin-doped indium oxide thin film, germanium oxide thin film, alumina thin film, zirconia thin film, SiO ₂ + MOx
(MOx is P ₂ O ₅ , B ₂ O ₃ , ZrO ₂ , TiO ₂ ,
At least one kind of metal oxide selected from Ta ₂ O ₅ and Nb ₂ O ₅ ) thin film can be mentioned as an example, but from the viewpoint of alkali diffusion preventing ability, it is a silicon oxide thin film or SiO ₂ containing P ₂ O. ₅ was added about 5 wt% film is particularly desirable.

When a conductive thin film is provided in one layer of the pre-coated thin film to impart an electromagnetic wave shielding function, a tin oxide thin film, an indium-added tin oxide thin film, and an oxide having both transparency to visible light and conductivity are provided. An indium thin film, a tin-added indium oxide thin film, and the like are preferable, and among them, an indium oxide transparent thin film containing 5 to 10% tin oxide is preferable because it has a high visible light transmittance and excellent conductivity.

Furthermore, the necessary condition for obtaining a titanium oxide thin film having high photocatalytic activity is that at least an anatase crystal is required. Since the anatase crystal undergoes a phase transition at a high film forming temperature or a high heat treatment temperature after the film formation and a part thereof changes to a rutile crystal, a titanium oxide thin film of anatase crystal containing a rutile crystal is also suitably used. However, if all the anatase crystals are converted to rutile crystals at high temperature, the titanium oxide thin film becomes cloudy due to the phase transition, which reduces the visible light transmittance, which is not preferable.

In the present invention, as the film forming method of the titanium oxide thin film and the pre-coated thin film, all the film forming methods which are usually used can be used. That is, the chemical vapor deposition method (C
VD method), spray method, spraying method of sol solution, pyrolysis method of thermally decomposing mist by ultrasonic waves, dip method, spin coating method, printing method, etc., as well as physical film forming method Various film forming methods such as a sputtering method, a vacuum evaporation method, an ion plating method, and a thermal spraying method using fine powder or sol can be adopted. Above all, considering the film formation on the window glass, the CVD method, the spray method,
A film forming method that can be incorporated into a window glass manufacturing process such as a pyrosol method is advantageous when industrial production is considered.
However, a film formation method that requires maintaining the substrate at a temperature higher than the glass softening point, for example, a temperature higher than 600 ° C. is preferable because it accelerates the deformation of the glass plate as the substrate and the diffusion of alkali components such as sodium from the substrate. Absent.

As a chemical agent for producing a pre-coated thin film,
The ones to produce a _{SiO 2, Si (OCH 3)} 4, Si (O
There are silicon alkoxides such as C ₂ H ₅ ) ₄ and SiCH ₃ (OCH ₃ ) ₃ and condensates thereof, and silicon halides such as SiCl _{4, and} as tin oxide-forming materials, Sn
(OCH ₃ ) ₄ , Sn (OC ₂ H ₅ ) ₄ , Sn (OC ₄ H ₉ ) ₄ , Sn
(AcAc) ₄ , Sn (OCOC ₇ H ₁₅ ) ₄ , SnCl ₄ , etc.,
In (OCH ₃ ) ₃ , which produces indium oxide,
_{In (OC 2 H 5) 3} , InCl 3, In (AcAc) 3, In (NO 3) 3
・ There are nH ₂ O, etc., and those that generate germanium oxide include Ge (OC ₂ H ₅ ) ₄ , Ge (OC ₄ H ₉ ) ₄ , GeCl
There are ₄ etc., and Al (O
_{C 2 H 5) 3, Al} (OC 3 H 7-i) 3, Al (OC 4 H 9)
₃ , In (AcAc) ₃ , In (NO 3) ₃ , nH ₂ O, etc.,
P (OC ₂ H ₅ ) ₃ , PO
_{(OCH 3) 3, PO (} OC 2 H 5) 3, H 3 PO 4, include P ₂ O _5, as producing boron oxide, B (OCH
₃ ) ₃ , B (OC ₂ H ₅ ) ₃ , B (OC ₄ H ₉ ) ₃ , B (AcAc)
₃ , BCl ₃ , H ₃ BO _3, etc., and these normally usable compounds or mixtures thereof can be used. In the chemical formula, AcAc represents CH ₃ COCHCOCH ₃ (acetylacetonate).

As a chemical agent for producing a titanium oxide thin film,
Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₃ H _7-i ) ₄ , Ti (OC ₄ H ₉ )
₄ , titanium alkoxides such as Ti (OC ₄ H ₉ ) ₂ Cl ₂ , titanium alkoxides with glycols such as ethylene glycol, carboxylic acids such as acetic acid and lactic acid, alkanolamines such as triethanolamine, β-diketones such as acetylacetone. An addition reaction product or complex with a compound, and a chloride such as TiCl ₄ dissolved in a general-purpose alcohol such as ethanol, a solvent such as acetic acid ester or β-diketone, or a mixture thereof can be used.

Various additives can be added by known methods to accelerate the photocatalytic reaction. For example, a trace amount of metal (gold, platinum, palladium, silver, copper, zinc) is uniformly supported on a titanium oxide thin film by a photodeposition method utilizing a photocatalytic reaction to such an extent that light transmission is not lost, and the oil decomposition activity It is also possible to impart a high self-cleaning property due to the improvement or a high antibacterial activity.

Further, in order to impart an electromagnetic wave shielding function, an indium-doped tin oxide film is formed on the precoat layer to impart conductivity, and a titanium oxide thin film is further formed on the indium-doped tin oxide film to form an electromagnetic wave from the outside. Can be shielded by the window glass according to the present invention.

[0054]

As described above in detail, the instrument cover glass according to the present invention is an instrument cover glass that is attached to instruments, and is placed outside at least when the glass plate is attached to the instrument. A titanium oxide thin film having a photocatalytic action is provided on at least a part of the surface, and the titanium oxide thin film has a linear transmittance of 50% or more for light with a wavelength of 550 nm and a linear transmittance of 50% or less for light with a wavelength of 350 nm. Yes, at least 300-400n
characterized in that it is composed of a material capable of decomposing linoleic acid by 0.5 μg or more per 1 cm ² of the titanium oxide thin film when irradiated with ultraviolet light containing a part of m light at an intensity of 5 mW / cm ^2. By adopting the above-mentioned configuration, it is possible to extremely effectively absorb the light having a wavelength of 400 nm or less that induces the photocatalytic action while sufficiently securing the light transmittance normally required as a cover glass for various instruments and adhere in a normal environment. This makes it possible to obtain an epoch-making self-cleaning performance that effectively decomposes the amount of fats and oils components.

[Brief description of drawings]

FIG. 1 is a sectional view of an instrument cover glass according to a first embodiment.

FIG. 2 is a sectional view of an instrument cover glass according to a sixth embodiment.

FIG. 3 is a table showing characteristics of instrument cover glasses according to Examples 1 to 10 and Comparative Examples 1 and 2.

FIG. 4 is a sectional view of an instrument cover glass according to a tenth embodiment.

[Explanation of symbols]

1 ... Glass plate, 2 ... Titanium oxide thin film, 3 ... Pre-coated thin film.

Front page continued (71) Applicant 592116165 Kazuhito Hashimoto 2 New City Hongodai D Building 213 No. 2703, 2073 Iijima-cho, Sakae-ku, Yokohama-shi, Kanagawa (71) Applicant 594180092 Tomoda YAMADA 3-12 Morinosato, Atsugi-shi, Kanagawa Bell Breeze Morinosato Building No. 2 Building No. 301 (72) Inventor Akira Fujishima 710 Nakamaruko Nakahara-ku, Kawasaki City, Kanagawa Prefecture 5 (72) Inventor Kazuhito Hashimoto 2073 Iijima Town, Sakae-ku Yokohama City, Kanagawa Prefecture New City Hongodai D Building 213 (72) Invention Author Tomokazu YATA 3-12, Morinosato, Atsugi City, Kanagawa Prefecture Bell Breeze Morinosato No. 2 Building No. 301 (72) Inventor Shigemichi Miyama 680 Takada, Odawara City, Kanagawa Prefecture (72) 345 Takada, Odawara City, Kanagawa Prefecture Japan Soda Co., Ltd. Odawara Research Institute (72) Inventor Tokuyoshi Saito 22-1 Otemachi, Chiyoda-ku, Tokyo Inside Soda Co., Ltd.

Claims (9)

[Claims] 1. A cover glass for an instrument, which is attached to an instrument, wherein a titanium oxide thin film having a photocatalytic action is provided on at least a part of a surface of a glass plate which is arranged outside when attached to the instrument. The titanium oxide thin film has a linear transmittance of 50% or more for light having a wavelength of 550 nm and a linear transmittance of 5 for light having a wavelength of 350 nm.
Ability to decompose linoleic acid to 0.5 μg or more per 1 cm ² of the titanium oxide thin film per hour when irradiated with ultraviolet light having an intensity of 5 mW / cm ² which is 0% or less and contains at least a part of light of 300 to 400 nm. A cover glass for an instrument, which is characterized by comprising 2. The titanium oxide thin film has a thickness of 0.1 to 5 μm.
It is m, The instrument cover glass of Claim 1 characterized by the above-mentioned. 3. The instrument cover glass according to claim 1, wherein the titanium oxide thin film contains at least anatase crystal. 4. The titanium oxide thin film contains at least one additive selected from the group consisting of silver, copper and zinc in an amount of 0.05 to 5 atom% based on titanium atoms. 5. The instrument cover glass according to any one of 1 to 3. 5. The instrument cover glass according to claim 1, further comprising a precoat thin film provided between the cover glass and the titanium oxide thin film. 6. The thickness of the pre-coated thin film is 0.02 to 1
The cover glass for a measuring instrument according to claim 5, wherein the cover glass for a measuring instrument is μm. 7. The precoat thin film is a thin film made of a material containing SiO ₂ as a main component.
Or the instrument cover glass according to item 6. 8. The instrument according to claim 4, wherein at least one layer of the pre-coated thin film contains a thin film made of a material containing indium oxide and / or tin oxide as a main component. cover glass. 9. The cover glass is made of glass whose main component is soda lime glass.
8. The instrument cover glass according to any one of 1 to 7.