JPH1153114A - Low reflection glass for substrate of touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low reflection glass for substrate of a touch panel, in which light reflection is reduced, glare feeling is dissolved and transparency is increased by forming multiple-layer films constituted of transparent oxide having specified refractive indexes and a thick film with a simple and efficient means. SOLUTION: In the substrate glass of the touch panel in which a transparent conductive film is formed on one face of the transparent substrate, a transparent oxide film 9 having the refractive index higher than the substrate 3 is stacked as the first layer from a substrate-side and a transparent oxide film 10 having the refractive index lower than the substrate 3 as the second layer on the surface and the back of the transparent glass substrate. Then, a transparent conductive film 2 is formed on one face of the substrate with the film and visible radiation reflectance is set to be 6% order or below with the light interruption operation of mutual films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistive touch panel disposed on various display devices and the like, that is, a conductive film is formed on the back surface of a transparent transparent surface plate, A conductive film pattern is formed on the upper surface of the transparent substrate, and the conductive film of both plates is brought into contact with each other by pressing an appropriate position of the surface plate, thereby conducting and inputting. The present invention relates to a low-reflection glass for a substrate of a touch panel, in which the light reflectance of the film-coated substrate is reduced and the transparency is improved.

[0002]

2. Description of the Related Art In display devices and the like, a low-reflection film is formed on the surface of a glass substrate or non-glare processing for forming fine irregularities is performed, thereby suppressing glare (glare) and improving transparency. Is known.

As for the touch panel, Japanese Patent Laid-Open No. 7-2099
In No. 3, non-glare processing, which provides fine irregularities on the surface of the resistive sheet (transparent conductive film) attached to the upper and lower panels that make up the touch panel, prevents interference fringes (Newton rings) and improves visibility Is disclosed.

Japanese Patent Application Laid-Open No. 5-127882 discloses that a λλ retardation plate, a polarizing plate,
It is disclosed that by laminating a non-glare-treated film, surface reflection is reduced, and antiglare properties, image contrast, and the like are improved.

[0005] Japanese Patent Application Laid-Open No. 6-124159 discloses a method of forming a thin ITO layer and a very thin SiOx layer alternately on an ITO film on a transparent substrate in a touch panel (touch key) to reduce light transmittance. It is disclosed to enhance.

The present invention is different from the known examples in that a multilayer film made of a transparent oxide having a specific refractive index and a specific thickness is formed by an easy and efficient means to reduce light reflection. An object of the present invention is to provide a low-reflection glass for a substrate of a touch panel, which eliminates glare and has increased transparency.

[0007]

According to the present invention, there is provided a glass for a touch panel substrate in which a transparent conductive film is formed on one side of a transparent glass substrate, wherein the first layer is formed on the front and back surfaces of the transparent glass substrate as the first layer from the substrate side. A transparent oxide film having a higher refractive index than the substrate, and then, as a second layer thereon, a transparent oxide film having a lower refractive index than the substrate is laminated, and a transparent conductive film is formed on one surface of the substrate with the film. In addition, the visible light reflectance is reduced to the order of 6% or less by the light interference effect between the films.

In one embodiment of the present invention, the first layer from the transparent glass substrate side has a refractive index n1 of 2.05 to 2.25,
A transparent oxide film having a thickness d1 of 90 to 120 nm, and then as a second layer thereon, a refractive index n2 of 1.43 to 1.48 and a thickness d2 of 30 to 60
a transparent oxide film having a thickness of about 10 nm to 25 nm, and a main wavelength of transmitted light of 480 to 560 nm and a transmission color of blue. It is preferable to use one that exhibits a green color.

In the above, the first layer is made of Ti
O ₂ , or TiO ₂ or Ta ₂ O ₅ with SiO ₂ , ZrO ₂ , SnO ₂ ,
A mixture of at least one of Al ₂ O ₃ , wherein the second layer film is made of SiO ₂ , or SiO ₂ , TiO ₂ , Ta ₂ O ₅ ,
It is preferable to use a mixture of one or more of ZrO ₂ , SnO ₂ , and Al ₂ O ₃ .

In another embodiment of the present invention, the first layer from the transparent glass substrate side has a refractive index n1 of 1.75 to 1.85,
A transparent oxide film having a thickness d1 of 30 to 80 nm, and then a second
As a layer, the refractive index n2 is 1.43 to 1.48, the film thickness d2 is 60 to 100
A transparent oxide film having a thickness of about 10 nm is formed on one side of the transparent oxide film, and a film having a thickness d3 of about 10 to 25 nm is formed. Those having a yellowish color are preferred.

In the above, the first layer is made of Si
O ₂ , TiO ₂ , ZrO ₂ , SnO ₂ , Al ₂ O ₃ and Ta ₂ O ₅ are appropriately mixed and prepared, and the second layer film is SiO ₂ , or SiO ₂ , TiO ₂ , It is preferable to use a mixture of at least one of ZrO ₂ , SnO ₂ , Al ₂ O ₃ , and Ta ₂ O ₅ .

In each of the above cases, the films of the first layer and the second layer are formed by a sol-gel method, and each film formed by the sol-gel method is formed on both sides of a glass substrate by a dipping method. It is desirable that the films are formed at the same time and at the same thickness.

[0013]

FIG. 4 shows a schematic partial structure of a general resistive touch panel in a display device. A transparent conductive material such as ITO is provided on an image display side of a main body 1 of a liquid crystal display device or the like. A substrate glass 3 on which a film pattern 2 is formed;
A transparent transparent surface plate 6 made of thin glass, resin or the like on which a transparent conductive film 5 such as ITO is formed via a spacer 4;
By pressing and bending the transparent surface plate 6 with a finger or a touch pen 7 from above, the transparent conductive film 5 of the surface plate 6 and the transparent conductive film pattern 2 of the glass for a substrate 3 come in contact with each other and are input. It is.

Incidentally, in the case of a transparent and clear float plate glass (mainly a soda-lime glass: a refractive index of about 1.5 to 1.6) commonly used for a substrate glass of a touch panel, the visible light transmittance is about 1 mm in glass thickness.
It is on the order of 91% and the visible light reflectance is on the order of 8%. In addition, as the glass for the substrate, in addition to the above-mentioned soda-lime glass, aluminosilicate glass, borosilicate glass and the like are also used, but their refractive indexes are almost in the range of 1.5 to 1.6, and the thickness is 0.2. Those having a size of a little less than mm to about 3 mm are employed.

As the transparent conductive film applied to the glass for the substrate,
In some cases, a Nesa (SnO ₂ ) film is used, but an ITO film (refractive index: around 1.95) is often used from the viewpoints of ease of patterning, conductivity, transparency, transparency, etc., and its thickness is suitable for touch panels. Taking into account the film resistance, transparency, etc., it is about 10 to 25 nm.

As shown in FIG. 2, the float plate glass having a thickness of 1.1 mm is used as a substrate glass 3 for a touch panel.
A transparent conductive film, for example, an ITO film 2 (refractive index n3
= 1.95, film thickness d3 = 10 to 25 nm), the ITO film surface side (arrow 8 side in the figure: the same applies to the following examples)
, The visible light transmittance is 90% or less, and the visible light reflectance exceeds 8%. For example, the visibility is poor, the glare is strong, and it cannot be said that it is suitable as a glass for a substrate.

Further, as shown in FIG.
m float glass to touch panel substrate glass 3
After forming one layer of low-reflection film 9 on both surfaces, an ITO film 2 (refractive index n3 = 1.95, film thickness d3 = 10 to 25) is formed on one surface.
nm), the refractive index of the low-reflection film 2 is set to about 1.45 and the refractive index of the low-reflection film 2 is set to about 1.45 in consideration of cancellation by interference of each reflected wave in the multiple reflection on the front and back surfaces of the ITO film and the low reflection film. Even in the case of a thickness of about 70 nm, the visible light transmittance slightly exceeds 90% on the ITO film side, and the visible light reflectance exceeds 8%. It is not suitable as glass for substrates.

On the other hand, as shown in FIG. 1, the same float plate glass having a thickness of 1.1 mm is used as the glass 3 for the substrate.
On both surfaces thereof, a transparent oxide film 9 higher than the substrate 3 as a first layer and a transparent oxide film 10 lower than the substrate as a second layer thereon are further laminated. By forming the ITO film 2 on one side and appropriately setting the thickness in consideration of the light interference between the films, the visible light reflectance can be reduced to the order of 6% or less.

That is, in one embodiment, the first layer 9 has a refractive index n1 of 2.05 to 2.25 and a thickness d1 of 90 to 120 nm.
As the transparent oxide film of the second layer 10, the refractive index n2 is 1.
43 ~ 1.48, film thickness d2 30 ~ 60nm to form a transparent oxide film,
Further, if an ITO film 2 (refractive index n3 = 1.95) is formed on one surface thereof with a film thickness d3 in the range of about 10 to 25 nm, the visible light transmittance is about 92 to 94% and the visible light reflectance is About 5 to 6.5%, the main wavelength of transmitted light is 480 to 560 nm, the transmitted color is pale blue or green, and it is less visibly tired, good, and suitable as low reflection glass .

The material of the first layer 9 is as follows.
Adopt TiO ₂ (refractive index 2.15) or TiO ₂ or Ta ₂ O
₅ (refractive index 2.3 to 2.5), SiO ₂ (refractive index 1.45), ZrO
₂ (refractive index: 1.90), SnO ₂ (refractive index: 1.85), and Al ₂ O ₃ (refractive index: 1.65), which are appropriately mixed.

The material of the second layer film 10 is as follows.
Adopted SiO _2, or _{SiO 2, TiO 2, Ta 2} O 5, ZrO 2,
A mixture of at least one of SnO ₂ and Al ₂ O ₃ is appropriately adopted.

In another embodiment, the first film 9 is a transparent oxide film having a refractive index n1 of 1.75 to 1.85 and a film thickness d1 of 30 to 80 nm. The rate n2 is 1.43-1.
48, a transparent oxide film having a film thickness d2 of 60 to 100 nm is formed, and an ITO film 5 (refractive index n3 = 1.95) is further formed on one surface thereof with a film thickness d3.
If the film is formed in the range of about 10 to 25 nm, the visible light transmittance is
93-95%, visible light reflectance is about 4-6%,
When the main wavelength of the transmitted light is around 570 nm, the transmitted color is slightly yellowish, and the glare is suppressed and good, and it can be applied as a low reflection glass.

In both of the above embodiments, the means for forming the first and second layer films include a spray method of preparing a coating solution, coating the coating solution on a substrate, heating and forming a film.
Dipping method, flow coating method, roller coating method,
Various chemical vapor deposition (CVD) methods, such as spin coating, or adjusting the organometallic compound vapor and spraying it on the substrate, as well as decomposing and forming a film, preparing a metal (oxide) target, Physical vapor deposition (PV
Although various methods such as D) method can be adopted, a dipping method which can efficiently form films of the same thickness on both surfaces of the substrate at the same time is preferable. As the coating solution, an organic metal compound such as a metal alkoxide or a metal β-diketonate is used. It is preferable to use a coating solution obtained by so-called sol-gel method of heating and forming a film by using a metal oxide sol solution as a starting material and a metal oxide sol solution as a starting material.

As the means for forming the ITO film, the above-mentioned various methods can be adopted, but the CVD method and the PVD method are often employed. A method called a pyrosol in which an aerosol of the salt is brought into contact with the above and an oxide film (ITO) is formed by thermal decomposition is awarded.

The refractive index and the thickness of each of the above films have a close correlation with each other. If the refractive index and the thickness of any of the films are out of the above ranges, the visible light transmittance and the visible light reflection are reduced. Rate and dominant wavelength range cannot be obtained.

[0026]

[Example 1: One embodiment] [Example 1-1] As a glass for a substrate of a touch panel,
A soda-lime glass (refractive index: 1.52) prepared by a float method plate with a size of 300 mm x 400 mm and a thickness of 1.1 mm was prepared, and both sides were polished with ceria, rinsed with water, and further wiped with a cloth soaked with isopropyl alcohol. . This is the temperature
In a clean room kept at 25 ° C. and a humidity of 50%, first and second low reflection films were formed by a sol-gel dipping method, and an ITO film was formed by a CVD method.

As a film forming raw material for the first layer, a trace amount of an acid catalyst and water are added to a solution obtained by diluting isopropyl titanate with isopropyl alcohol, and the mixture is stirred. It was prepared by adding isopropyl alcohol to 0.45 wt% to obtain a titania sol solution. The viscosity of this solution was about 3.0 mPa · s.

The glass substrate was immersed in a bath containing the solution, pulled up at a speed of about 4.5 mm / s so that the thickness after firing became the desired thickness, and the coating liquid was applied to both surfaces of the glass substrate. . This was further heated at 270 ° C. for 15 minutes to form a titania gel film.

As a material for forming a film for the second layer, a trace amount of an acid catalyst and water are added to a solution of tetraethoxysilane diluted with isopropyl alcohol, and the mixture is stirred.
Isopropyl alcohol was added to adjust to 30 wt% to obtain a silica sol solution. The viscosity of this solution is about 2.8
mPa · s.

The glass substrate on which the first layer film is formed is immersed in the bath containing the solution, and is pulled up at a speed of about 1.2 mm / s so that the film thickness after firing becomes the desired thickness. After coating the coating solution on both sides of the glass substrate with a layer film,
After heating for 1 minute, a silica gel film was formed on the titania gel film.

Further, the glass substrate was heated and fired at 470 ° C. for 30 minutes to complete a low reflection film comprising a first layer of titania film and a second layer of silica film on both surfaces of the glass. On one side of this two-layer glass-coated glass substrate, aerosolized indium salt and tin salt are introduced and thermally decomposed to form an ITO film by the so-called CVD-pyrosol method, completing low-reflection glass for touch panel substrates. did.

[0032] Note that low reflection glass has a refractive index n1 is 2.15 as the first layer film, TiO ₂ film having a thickness d1 is 104 nm, the refractive index n2 of 1.45 as the second layer film, the thickness d2 is 42 nm SiO ₂ IT with a refractive index n3 of 1.95 and a film thickness d3 of 19 nm
Consists of an O film.

The low reflection glass for the substrate of the touch panel is as follows:
93.8% visible light transmittance at normal incidence, visible light reflectance
5.6%, the visible light reflectance can be reduced by about 5% and the visible light transmittance can be improved by about 5% compared to the case where a 19nm ITO film is formed directly on a glass plate. Was suppressed.

Further, it has a transmission color tone of light bluish green (the main wavelength of the transmitted light is 546 nm), has no visual fatigue or discomfort, and is suitable as a low reflection glass for a substrate of a touch panel.

Example 1-2 A glass substrate similar to that of Example 1-1 was prepared. A solution in which tantalum ethoxide and silicon ethoxide are mixed at a solute concentration (molar ratio in terms of oxide) of 85:15 as a film forming raw material of the first layer, diluted with isopropyl alcohol, and an acid catalyst, water and the like are added. Then, isopropyl alcohol was further added to adjust the solute concentration to 0.40% by weight to obtain a sol solution of tantalum oxide and silica. The viscosity of this solution was about 2.8 mPa · s.

The glass substrate is immersed in a bath containing the solution, pulled up at a speed of about 4.6 mm / s, and then heated at about 300 ° C.
Heat for 10 minutes and apply the first layer of tantalum oxide on both sides of the glass.
A silica composite gel film was formed.

Next, the glass substrate on which the first layer was applied was immersed in the same silica sol solution as used for the second layer in Example 1-1, and was pulled up at a speed of about 1.3 mm / s. About 3
By heating at 00 ° C. for 10 minutes, a silica gel film was formed on the tantalum oxide-silica composite gel film.

Further, the glass substrate was heated and baked at 470 ° C. for 30 minutes, and the first layer of tantalum oxide (85 wt%) was formed on both surfaces of the glass.
A low reflection film composed of a silica (15 wt%) composite film and a second layer silica film was completed.

On one side of this two-layer film-coated glass substrate, an actual
In the same manner as in Example 1-1, an ITO film is formed by CVD and touch
Completed low reflection glass for panel substrates. The low reflection
Glass has a refractive index n1 of 2.15 and a thickness d1 of 1 as a first layer film.
00nm Ta _TwoO_Five ・ SiO_TwoThe refractive index n2 is 1.4 as the film and the second layer film.
5.SiO with thickness d2 of 48nm_TwoFilm, and a transparent conductive film on one side
Thus, an ITO film having a refractive index n3 of 1.95 and a thickness d3 of 16 nm is formed.

The low reflection glass for the substrate of the touch panel is as follows:
94.3% visible light transmittance at normal incidence, visible light reflectance
5.1%, visible light reflectivity can be reduced by about 5% and visible light transmittance can be improved by about 5%, compared to a case where a 16nm ITO film is formed directly on a glass plate. Was suppressed. In addition, the transmission color tone was green (the main wavelength of the transmitted light was 515 nm), and there was no feeling of fatigue or discomfort in sight, and thus it was suitable as a low reflection glass for a touch panel substrate.

Example 1-3 The same glass substrate as in Example 1-1 was immersed in the first-layer titania sol solution prepared in Example 1-1, and the glass substrate was pulled up at a speed of about 4.6 mm / s. Was coated with a coating solution. This was further heated at 270 ° C. for 15 minutes to form a titania gel film.

Aluminum sec-butoxide was diluted with isopropyl alcohol and adjusted by adding an acid catalyst and water, while silicon ethoxide was similarly diluted by isopropyl alcohol and adjusted by adding an acid catalyst and water. The aluminum sol solution and the silica sol solution were mixed at a solute concentration ratio (molar ratio in terms of oxide) of 15:85, and isopropyl alcohol was added to adjust the solute concentration to 0.30 wt%. Obtained. The viscosity of this solution was about 2.5 mPa · s, which was used as a film forming raw material for the second layer.

The glass substrate on which the one layer is formed is immersed in this solution, pulled up at a speed of about 1.5 mm / s,
Heat at 70 ° C for 15 minutes to apply alumina
A silica gel film was formed.

Further, the glass substrate was heated and baked at 470 ° C. for 30 minutes to complete a low reflection film comprising a first layer of titania film and a second layer of alumina / silica composite film on both surfaces of the glass. An ITO film was formed on one surface of the two-layer film-coated glass substrate by the CVD method in the same manner as in Example 1-1, and a low-reflection glass for a touch panel substrate was completed.

The low-reflection glass is a TiO ₂ film having a refractive index n1 of 2.15 and a thickness d1 of 105 nm as a first layer film, and an Al ₂ O 3 film having a refractive index n2 of 1.47 and a thickness d2 of 45 nm as a second layer film. O ₃ · SiO ₂ film, furthermore, as a transparent conductive film on one side, the refractive index n3 is 1.95, the film thickness d3 is 16
It consists of nm ITO film.

The low reflection glass for the substrate of the touch panel is as follows:
94.2% visible light transmittance at normal incidence, visible light reflectance
5.2%, visible light reflectance can be reduced by about 5% and visible light transmittance can be improved by about 5%, compared to the case where a 16nm ITO film is simply formed directly on a glass plate. Was suppressed.

Further, although the transmission color tone was slightly yellowish, it was green (the main wavelength of transmitted light was 557 nm), and it was suitable for low reflection glass for a substrate of a touch panel without a feeling of fatigue or discomfort on visual perception.

[Comparative Example 1-1] An ITO film having a thickness of 19 nm was formed directly on one surface of a glass substrate by the same CVD method as in Example 1-1 without forming a low-reflection laminated film on the same glass substrate as in Example 1-1.
A thick film was formed to form a glass for a substrate of a touch panel.

The visible light reflectance of this glass at normal incidence was 10.7%, and the visible light transmittance was 88.7%. When this is incorporated into a display device as a touch panel, the surrounding background is reflected as a reflected image, and the screen is very hard to see with glare, making it uncomfortable and tired, making it unsuitable for touch panels. Met.

Comparative Example 1-2 A glass substrate similar to that of Example 1-1 was immersed in a titania sol solution for the first layer similar to that of Example 1-1, pulled up at a speed of 6.0 mm / s, and further dried. ° C
For 15 minutes to form a first layer of titania gel film. Then, it was immersed in the same silica sol solution for the second layer as in Example 1-1, pulled up at a speed of 4.0 mm / s, and further heated to 270 ° C.
For 15 minutes to form a titania gel film for the second layer,
After that, it is heated and baked at 470 ° C for 30 minutes.
A two-layer film composed of a titania film as a layer and a silica film as a second layer was completed.

An ITO film was formed on one surface of the glass substrate with the two-layer film by the CVD method in the same manner as in Example 1-1, and a glass for a substrate of a touch panel was completed. The glass was made of TiO ₂ having a refractive index n1 of 2.15 and a thickness d1 of 130 nm as a first layer film.
Film with a refractive index n2 of 1.45 and a thickness d2 of 70 nm
SiO ₂ film, furthermore as one side transparent conductive film refractive index n3 is 1.95,
It is made of an ITO film having a thickness d3 of 19 nm.

The glass for a substrate of the touch panel has a visible light transmittance of 91.7% at normal incidence and a visible light reflectance of 7.4%. The transmittance is low while the reflectance is high as compared with the embodiment, and the transmission color is low. Yellow (primary wavelength is 587nm)
It is not suitable for touch panels.

Comparative Example 1-3 A glass substrate similar to that of Example 1-1 was immersed in a titania sol solution for the first layer similar to that of Example 1-1, pulled up at a speed of 3.0 mm / s, and further dried. ° C
For 15 minutes to form a first layer of titania gel film. Then, it was immersed in the same silica sol solution for the second layer as in Example 1-1, pulled up at a rate of 0.6 mm / s, and further heated to 270 ° C.
For 15 minutes to form a silica gel film for the second layer, and then heat at 470 ° C. for 30 minutes to form a two-layer film consisting of the first titania film and the second silica film on both surfaces of the glass. completed.

An ITO film was formed on one surface of the glass substrate provided with the two-layer film by the CVD method in the same manner as in Example 1-1 to complete a glass for a substrate of a touch panel. In addition, this glass has a refractive index n1 of 2.15 and a thickness d1 of 80 nm as a first layer film.
S film having a refractive index n2 of 1.45 and a film thickness d2 of 25 nm as a _second film and a second layer film
iO ₂ film, furthermore as one side transparent conductive film refractive index n3 is 1.95,
It is made of an ITO film having a thickness d3 of 19 nm.

The glass for the substrate of the touch panel has a transmitted color of bluish green (main wavelength is 481 nm) and has no unnaturalness in color tone, but has a visible light transmittance of 78.2% at normal incidence and a visible light reflectance of 21%. The reflectance is extremely high while the transmittance is extremely low as compared with the embodiment, and is not suitable for touch panels.

Comparative Example 1-4 A glass substrate similar to that in Example 1-1 was prepared. As a film forming raw material for the first layer, isopropyl titanate and ethyl silicate were mixed at a molar ratio of 50:50 in terms of oxide to prepare a solute concentration of 0.42% by weight in an isopropyl alcohol solvent. -A silica composite sol solution was obtained.

The glass substrate was immersed in a bath containing this solution, pulled up at a speed of about 3.9 mm / s, and then heated at about 270 ° C. for 15 minutes.
After heating for 1 minute, a first layer of titania-silica composite gel film was formed on both surfaces of the glass.

Example 1 as a film forming raw material for the second layer
-1 Prepare the same silica sol solution (with a solute concentration of 0.40 wt%), immerse the first-layer-film-forming glass substrate in a bath containing the solution, and pull up at a speed of about 3.9 mm / s. ,about
By heating at 270 ° C. for 15 minutes, a silica gel film was formed on the titania-silica composite gel film.

Further, the glass substrate was heated at 470 ° C. for 30 minutes to form a two-layer film composed of a first-layer titania-silica composite film and a second-layer silica film on both surfaces of the glass. The glass with a two-layer film has a refractive index as a first layer film.
n1 is 1.79, film thickness d1 is a SiO ₂ / TiO ₂ film having a thickness of 77 nm, and as a second layer film, refractive index n2 is 1.45 and film thickness d2 is 95
It consisted of a ₂ nm nm SiO ₂ film and had a very low reflectivity of 0.8% for visible light.

An ITO film was formed on one surface of the glass substrate provided with a two-layer film by the CVD method in the same manner as in Example 1-1 to complete a substrate glass for a touch panel. However, this glass had a visible light reflectance of 8.1%, which was as high as unformed glass, and was unsuitable for touch panels.

Comparative Example 1-5 A glass substrate similar to that of Example 1-1 was prepared. A glass substrate was immersed in the same second-layer silica sol solution as in Example 1-1, pulled up at a speed of 4.0 mm / s to form a film, heated at 270 ° C. for 15 minutes, and further formed at 480 ° C. For 30 minutes to obtain a silica film.

An ITO film was formed on one surface of the glass with the silica film by the CVD method in the same manner as in Example 1-1. as a result,
A glass for a touch panel substrate was formed in which a silica film having a refractive index of 1.45 and a thickness of 70 nm was formed on both sides of a glass plate, and an ITO film having a refractive index of 1.95 and a thickness of 19 nm was formed on one side.

The glass for the substrate of the touch panel thus formed has a visible light transmittance of 91.3% and a visible light reflectance of 8.2%, and has a reflectance of about 2.5% as compared with the glass for the touch panel substrate of Example 1-1. High and the main wavelength of transmitted light is 570nm
And yellow, which was not preferable for touch panels.

[0064]

[Example 2: Another aspect] [Example 2-1] As a glass for a substrate of a touch panel,
Same as Example 1-1, size 300mm × 400mm, thickness 1.1m
Prepare a soda-lime glass (refractive index: 1.52), which is made by float plate making of m, and grind both surfaces with ceria,
Rinse with water and wipe with a cloth soaked in isopropyl alcohol. In a clean room maintained at a temperature of 25 ° C. and a humidity of 50%, the first and second layers for low reflection are formed by a sol-gel dipping method, and ITO is formed by a CVD method.
A film was formed.

As a film forming raw material for the first layer, a small amount of an acid catalyst and water are added to a solution obtained by diluting tetraethoxysilane with isopropyl alcohol, followed by stirring. Separately, a solution obtained by diluting isopropyl titanate with isopropyl alcohol is prepared. A small amount of an acid catalyst and water are added and stirred, and both these solutions are mixed so that the molar ratio in terms of silica: titania becomes 50:50, and the solute concentration in terms of oxide is about 0.42 wt%.
Was prepared by further adding isopropyl alcohol to obtain a silica-titania sol solution. The viscosity of this solution was about 2.5 mPa · s.

The glass substrate was immersed in a bath containing the solution, pulled up at a rate of about 2.0 mm / s so that the thickness after firing became a desired thickness, and the coating liquid was applied to both surfaces of the glass substrate. . This was further heated at 270 ° C. for 15 minutes to form a silica-titania gel film.

As a film forming raw material for the second layer, a small amount of an acid catalyst and water are added to a solution of tetraethoxysilane diluted with isopropyl alcohol, and the mixture is stirred.
Isopropyl alcohol was added so as to be 40 wt% to obtain a silica sol solution. The viscosity of this solution is about 2.9m
Pa · s.

The glass substrate on which the first layer film is formed is immersed in a bath containing the solution, and is pulled up at a speed of about 3.0 mm / s so that the film thickness after firing becomes the desired thickness. After coating the coating solution on both sides of the glass substrate with a layer film,
After heating for a minute, a silica gel film was formed on the silica-titania gel film.

Further, the glass substrate was heated and baked at 470 ° C. for 30 minutes to form a first layer of silica / titania film on both surfaces of the glass,
A low-reflection film made of a second-layer silica film was completed. This 2
On one side of the glass substrate with a layer film, aerosolized indium salt and tin salt are guided and pyrolyzed at about 500 ° C.
An ITO film was formed by the so-called CVD-pyrosol method, and a low-reflection glass for a touch panel substrate was completed.

The low-reflection glass had a refractive index n1 of 1.80 and a thickness d1 of 50 nm as a first layer film, and a SiO ₂ / TiO ₂ film having a thickness of 50 nm, and a refractive index n2 of 1.45 and a thickness d2 of 85 nm as a second layer film. SiO ₂ film, further refractive index n3 is 1.95 as the transparent conductive film layer of the single-sided, film thickness d3 is 19nm
Consisting of ITO film.

The low reflection glass for a substrate of the touch panel is as follows:
94.8% visible light transmittance at normal incidence, visible light reflectance
This is 4.5%, which reduces visible light reflectance by about 6% and improves visible light transmittance by about 6%, compared to a 19-nm ITO film formed directly on a glass plate. Was suppressed. In addition, the transmission color tone was light yellow (the main wavelength of transmitted light was 568 nm), which did not impair the visibility, and was sufficiently applicable as a low-reflection glass for a touch panel substrate.

[Example 2-2] A glass plate (1.8 mm thick) having the same float method as that of Example 2-1 was prepared.
-1 Cleaned and prepared similarly.

As a film forming raw material of the first layer, zirconium tetraethoxide was dissolved in isopropyl alcohol, and an acid catalyst, water and the like were added and adjusted. To the same material, an isopropyl alcohol solution of silicon ethoxide, which was similarly adjusted, was added. The oxides were mixed at a molar ratio of 80:20, and the solute concentration was further adjusted to 0.30 wt% to obtain a zirconia-silica sol solution. The viscosity of this solution was about 3.0 mPa · s.

The glass substrate was immersed in a bath containing this solution, pulled up at a speed of about 4.0 mm / s, and then heated at about 300 ° C.
Heating was performed for 10 minutes to form a first-layer zirconia-silica composite gel film on both surfaces of the glass.

Next, the glass substrate on which the one layer was applied was immersed in the same silica sol solution as used for the second layer in Example 2-1 and pulled up at a speed of about 2.5 mm / s. About 3
By heating at 00 ° C. for 10 minutes, a silica gel film was formed on the zirconia-silica composite gel film.

Further, the glass substrate was heated and baked at 470 ° C. for 30 minutes to form a first layer of zirconia (80 mol%) on both surfaces of the glass.
A low-reflection film composed of a silica (20 mol%) composite film and a second-layer silica film was completed.

An ITO film was formed on one surface of the glass substrate provided with a two-layer film by the CVD method in the same manner as in Example 2-1 to complete a low reflection glass for a substrate of a touch panel. The low reflection glass has a refractive index n1 of 1.79 and a thickness d1 of 70 as the first layer film.
a ₂ nm thick ZrO ₂ · SiO ₂ film, a SiO ₂ film with a refractive index n2 of 1.45 and a thickness d2 of 75 nm as a _second layer film, and an ITO film with a refractive index n3 of 1.95 and a thickness d3 of 16 nm as a transparent conductive film on one side. Consists of a membrane.

The low reflection glass for the substrate of the touch panel is as follows:
95.7% visible light transmittance at normal incidence, visible light reflectance
3.7%, visible light reflectance can be reduced by about 6.5%, and visible light transmittance can be improved by about 6.5%, compared to a case where a 16nm ITO film is simply formed directly on a glass plate. Was suppressed. In addition, the transmission color tone was light yellow (the main wavelength of the transmitted light was 567 nm), and did not impair the visual sensation, and could be adequately applied as a low reflection glass for a touch panel substrate.

Example 2-3 The same glass substrate as in Example 2-1 was immersed in the first-layer titania / silica sol solution prepared in Example 2-1 and pulled up at a speed of about 2.0 mm / s. The coating liquid was applied on both sides of the substrate. At 270 ° C
Heating for 15 minutes formed a titania-silica gel film.

Further, aluminum sec-butoxide was diluted with isopropyl alcohol and adjusted by adding an acid catalyst and water, while silicon ethoxide was similarly diluted by isopropyl alcohol and adjusted by adding an acid catalyst and water.
The aluminum sol solution and the silica sol solution were mixed at a solute concentration ratio (molar ratio in terms of oxide) of 15:85, and isopropyl alcohol was added to adjust the solute concentration to 0.30 wt%. Obtained. The viscosity of this solution was about 2.5 mPa · s, which was used as a film forming raw material for the second layer.

The glass substrate on which the one layer was formed was immersed in this solution, pulled up at a speed of about 4.8 mm / s,
Heat at 70 ° C for 15 minutes to apply alumina
A silica gel film was formed.

Further, the glass substrate was heated and fired at 470 ° C. for 30 minutes to complete a low reflection film comprising a first layer of titania film and a second layer of alumina / silica composite film on both surfaces of the glass. An ITO film was formed on one surface of the glass substrate with the two-layer film by the CVD method in the same manner as in Example 2-1 to complete a low-reflection glass for a substrate of a touch panel.

The low-reflection glass has a refractive index n1 of 1.80 and a thickness d1 of 50 nm as a TiO ₂ .SiO ₂ film as a first layer film, and a refractive index n2 of 1.47 and a thickness d2 of 80 nm as a second layer film. Al ₂ O ₃・ SiO
_It is composed of two films and an ITO film having a refractive index n3 of 1.95 and a film thickness d3 of 16 nm as a transparent conductive film on one side.

The low reflection glass for the substrate of the touch panel is as follows:
94.6% visible light transmittance at normal incidence, visible light reflectance
4.8%, the visible light reflectance can be reduced by about 5.5% and the visible light transmittance can be improved by about 5.5%, compared to the case where a 16nm ITO film is simply formed directly on a glass plate, and the visibility is good and the glare is good. Was suppressed.

Although the transmission color tone was slightly yellow (the main wavelength of the transmitted light was 564 nm), there was no visual fatigue or uncomfortable feeling, and the glass was suitable as a low reflection glass for a touch panel substrate.

Comparative Example 2-1 The same glass substrate as in Example 2-1 was immersed in the same first layer titania / silica sol solution as in Example 2-1 and pulled up at a speed of 5.0 mm / s. Further heating was performed at 270 ° C. for 15 minutes to form a first layer of titania-silica gel film. Then, it is immersed in the same silica sol solution for the second layer as in Example 1, pulled up at a speed of 4.0 mm / s, and further heated at 270 ° C. for 15 minutes to form a titania gel film for the second layer. By heating and baking at 470 ° C. for 30 minutes, a two-layer film composed of a first-layer titania film and a second-layer silica film on both surfaces of the glass was completed.

An ITO film was formed on one surface of the glass substrate provided with a two-layer film by a CVD method in the same manner as in Example 2-1 to complete a glass for a substrate of a touch panel. In addition, this glass was made of TiO _2.
SiO ₂ film, the refractive index n2 is 1.45 and the film thickness d2 is 100
nm of SiO ₂ film, further refractive index n3 as a transparent conductive film of one side 1.
95, consisting of an ITO film with a thickness d3 of 19 nm.

The glass for the substrate of the touch panel has a visible light transmittance of 87.4% at normal incidence and a visible light reflectance of 12.0%.
And the reflectance is high while the transmittance is low as compared with the embodiment,
It is not suitable for touch panels.

[Comparative Example 2-2] A glass substrate similar to that of Example 2-2 was replaced with a zirconia for the first layer similar to that of Example 2-2.
Dipped in a silica sol solution, pulled up at a speed of 1.6 mm / s,
It was further heated at 300 ° C. for 10 minutes to form a first layer of a zirconia-silica gel film. Then, it was replaced with the second
Dipped in a silica sol solution for the layer, pulled up at a speed of 1.5 mm / s, and further heated at 300 ° C. for 10 minutes to form a silica gel film for the second layer, and then heated at 470 ° C. for 30 minutes, A two-layer film comprising a first layer of zirconia-silica film and a second layer of silica film on both surfaces was completed.

An ITO film was formed on one surface of the glass substrate provided with a two-layer film by the CVD method in the same manner as in Example 2-1 to complete a glass for a touch panel substrate. Note the glass has a refractive index n1 as the first layer film is 1.79, the film thickness d1 is 30nm of ZrO ₂ · Si
O ₂ film, the refractive index n2 is 1.45 and the film thickness d2 is 50 nm as the second layer film.
SiO ₂ film, furthermore as one side transparent conductive film refractive index n3 is 1.95,
It is made of an ITO film having a thickness d3 of 19 nm.

The glass for the substrate of the touch panel has a visible light transmittance of 83.7% at normal incidence and a visible light reflectance of 15.7%, and the transmittance is almost the same as that obtained by directly forming an ITO film on a glass plate. Although it is low, it has a high reflectance and is not suitable for touch panels.

Comparative Example 2-3 The same glass substrate as in Example 2-1 was immersed in the same titania / silica sol solution as in Example 1, pulled up at a speed of 3.9 mm / s, and then heated at about 270 ° C. for 15 minutes.
After heating for 1 minute, a first layer of titania-silica gel film was formed on both surfaces of the glass.

Next, the glass substrate on which the first layer film was formed was immersed in the same silica sol solution as in Example 2-1 to obtain about 3.9 mm / s.
Then, the mixture was heated at about 270 ° C. for 15 minutes to form a silica gel film on the titania silica gel film.

Further, the glass substrate was heated at 470 ° C. for 30 minutes to form a first layer of titania-silica film on both sides of the glass,
A two-layer film composed of a two-layer silica film was completed. The two-layer film-coated glass substrate has a refractive index n1 of 1.79 and a film thickness d1 as a first layer film.
Is 77 nm SiO ₂ / TiO ₂ film, refractive index n2 is 1.4 as the second layer film
5.The thickness d2 is composed of 95nm SiO ₂ film, and the visible light reflectance is
It had a very low reflectivity of 0.8%.

An ITO film was formed on one surface of the glass substrate provided with a two-layer film by the CVD method in the same manner as in Example 2-1 to complete a substrate glass for a touch panel. However, this glass had a visible light reflectance of 8.1%, which was as high as bare glass on which a low reflection film and an ITO film were not formed, and was unsuitable for touch panels.

Comparative Example 2-4 A glass substrate similar to that in Example 2-1 was prepared. A glass substrate was immersed in a silica sol solution of the second layer in the same manner as in Example 2-1 and pulled up at a speed of 4.0 mm / s to form a film. For 30 minutes to obtain a silica film.

An ITO film was formed on one side of this glass with a silica film by the CVD method in the same manner as in Example 2-1. as a result,
A glass for a touch panel substrate was formed in which a silica film having a refractive index of 1.45 and a thickness of 70 nm was formed on both sides of a glass plate, and an ITO film having a refractive index of 1.95 and a thickness of 19 nm was formed on one side.

The glass for a substrate of the touch panel thus formed has a visible light transmittance of 91.3% and a visible light reflectance of 8.2%, and has a reflectance of about 4% as compared with the glass for a touch panel substrate of Example 2-1. It was expensive and was not preferable for touch panels.

[0099]

As described above, according to the low reflection glass for a substrate of a touch panel of the present invention, a multi-layered film made of a transparent oxide having a specific refractive index and a film thickness is formed by an easy and efficient means to reduce light reflection. This has the effect of reducing, reducing glare, and increasing transparency.

[Brief description of the drawings]

FIG. 1 is a schematic partial side cross-sectional view of a glass substrate provided with a low-reflection two-layer film over a glass for a substrate of a touch panel.

FIG. 2 is a schematic partial side sectional view of a glass substrate for a touch panel, which is a glass substrate on which a low reflection film is not formed.

FIG. 3 is a schematic partial side sectional view of a glass substrate provided with a low-reflection single-layer film over a glass for a substrate of a touch panel;

FIG. 4 is a schematic partial sectional side view of the entire touch panel.

[Explanation of symbols]

 2 Transparent conductive film (ITO film) 3 Glass for touch panel substrate 9 First layer transparent oxide film 10 Second layer transparent oxide film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Moriguchi 1510 Oguchicho, Matsusaka-shi, Mie Central Glass Co., Ltd. Inside Glass Research Laboratories (72) Inventor Shigeo Yamada 12-8, Goi-minamikachi, Ichihara-shi, Chiba Nisso Chemical Co., Ltd. Inside the Production Engineering Laboratory

Claims (5)

[Claims] 1. A glass for a touch panel substrate having a transparent conductive film formed on one surface of a transparent glass substrate, wherein a transparent oxide having a higher refractive index than the substrate is provided on the front and back surfaces of the transparent glass substrate as a first layer from the substrate side. A transparent oxide film having a lower refractive index than that of the substrate, and a transparent conductive film formed on one surface of the substrate with the film,
A low-reflection glass for a substrate of a touch panel, wherein the visible light reflectance is reduced to the order of 6% or less by a light interference effect between films. 2. As a first layer from the transparent glass substrate side,
A transparent oxide film having a refractive index n1 of 2.05 to 2.25 and a thickness d1 of 90 to 120 nm, and then a second layer thereon has a refractive index n2 of 1.43
~ 1.48, a transparent oxide film with a film thickness d2 of 30 ~ 60nm is formed, and on one surface thereof, an ITO film is formed with a film thickness d3 in a range of about 10 ~ 25nm, and the main wavelength of transmitted light 2. The low-reflection glass for a touch panel substrate according to claim 1, wherein the glass has a wavelength of 480 to 560 nm and a transmission color of blue to green. 3. As a first layer from the transparent glass substrate side,
The refractive index n1 is 1.75 to 1.85, the thickness d1 is 30 to 80 nm, a transparent oxide film, and then as a second layer thereon, the refractive index n2 is 1.43 to
1.48, a transparent oxide film with a thickness d2 of 60 to 100 nm is formed, and an ITO film is further formed on one surface with a thickness d3 in a range of about 10 to 25 nm, and the main wavelength of transmitted light is 2. The low reflection glass for a substrate of a touch panel according to claim 1, wherein the transmission color exhibits a slightly yellowish color at around 570 nm. 4. The low reflection glass for a touch panel substrate according to claim 1, wherein the first and second layers are formed by a sol-gel method. 5. The low-reflection glass for a touch panel substrate according to claim 1, wherein the film formed by the sol-gel method is simultaneously formed on both surfaces of the glass substrate by a dipping method.