JP2002348145A - Near-infrared-ray shielding glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, at a low cost, a near-infrared-ray shielding glass which has a high visible-light transmittance of >=80% and a low solar-light transmittance of <=60% by adjusting the combination of high refractive-index films and low refractive-index films laminated on a glass plate and adjusting the number of the lamination. SOLUTION: The near-infrared-ray shielding film is manufactured by laminating a low refractive-index film, a high refractive-index film, a low refractive- index film, a high refractive-index film, and a low refractive-index film in this order. When the thickness of the glass plate is 3 mm, the visible light transmittance is >=80% and the solar light transmittance is <=60%. The low refractive-index film essentially consists of silicon oxide. The high refractive- index film essentially consists of titanium oxide and its refractive index in 350-800 nm wavelength is >=2.6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near-infrared shielding glass in which films having different refractive indexes are alternately laminated on the surface of a glass plate.

[0002]

2. Description of the Related Art Conventionally, an ultraviolet shielding glass or a near infrared shielding glass in which a transparent thin film containing silicon oxide, titanium oxide or tin oxide as a main component is laminated on the surface of a glass plate has been widely known. These ultraviolet or near-infrared shielding glasses exhibit ultraviolet or near-infrared shielding performance by alternately laminating low-refractive-index films and high-refractive-index films and utilizing the optical interference effect of a multilayer film structure. It is. Regarding this optical interference effect, the effect is more likely to be obtained as the refractive index difference between the low refractive index film and the high refractive index film is large.However, in a conventional multilayer film, it cannot be said that the combination has been thoroughly studied, There was room for improvement. For example, Japanese Patent Application Laid-Open No. 10-291839 discloses a refractive index of 1.
An ultraviolet heat ray reflective glass article having a three-layer structure comprising a low refractive index film having a refractive index of 6 or less and a high refractive index film having a refractive index of 2.0 to 2.6 is described. The sunlight transmittance of the glass articles described in the examples of this publication was 61% or more, and the near-infrared ray blocking performance was not always sufficient.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem. The purpose is to adjust the combination of the low refractive index film and the high refractive index film to be laminated on the glass plate and the number of the laminated layers so that the visible light transmittance is as high as 80% or more, and An object of the present invention is to provide a near-infrared shielding glass having a low light transmittance of 60% or less at a low cost.

[0004]

In order to solve the above-mentioned problems, the near-infrared shielding glass according to the first aspect of the present invention has a low refractive index film, a high refractive index film, and a low refractive index film on a glass plate. A film, a high-refractive-index film and a low-refractive-index film are laminated in this order, and when the glass plate is 3 mm, the visible light transmittance is 80% or more and the sunlight transmittance is 60% or less. And the low refractive index film is a film mainly composed of silicon oxide, the high refractive index film is mainly composed of titanium oxide, and has a refractive index at a wavelength of 350 to 800 nm of 2.
6 or more films.

A near-infrared shielding glass according to a second aspect of the present invention is the near-infrared shielding glass according to the first aspect of the present invention, wherein the film mainly composed of titanium oxide is formed by a thermal decomposition method. The glass temperature immediately before film formation in the method is 55
0 ° C or higher.

[0006]

Embodiments of the present invention will be described below in detail. In addition, it is not limited to the following embodiment.

This near-infrared blocking glass has a low refractive index film mainly composed of silicon oxide on a glass plate and a high refractive index film mainly composed of titanium oxide and having a refractive index of 2.6 or more at a wavelength of 350 to 800 nm. The refractive index film and 5 are alternately arranged in this order.
The layers are laminated. The low-refractive-index film containing silicon oxide as a main component is a film having a basic skeleton of Si-O bonds, and includes a film in which the valence of silicon is partially changed and a film containing an alkali component and other dopants. It is. Examples of the dopant include fluorine, chlorine, silicon, aluminum, zinc, copper, indium, bismuth, gallium, boron, vanadium, manganese, and zirconium. The concentration of these dopants is 0.02% by weight
The following is preferred. Further, a silicon oxycarbide film containing carbon or a silicon oxynitride film containing nitrogen may be used. The thickness of the film containing silicon oxide as a main component is preferably 200 nm or less.

The low refractive index film has a refractive index at a wavelength of 550 nm of 1.42 to 1.50. As described above, as the refractive index of the low refractive index film is lower and the refractive index of the high refractive index film is higher, the near-infrared blocking effect is better exhibited. Therefore, it is preferable that the low refractive index film is a film having a refractive index of 1.46, that is, a film made of substantially pure silicon dioxide (hereinafter, referred to as a “silica film”). Since a film containing silicon oxide as a main component has a dense and strong basic skeleton, if it is directly formed on the surface of a glass plate, it exhibits an excellent alkali barrier function. By exhibiting the alkali barrier function, it is possible to prevent the film containing titanium dioxide as a main component from being deteriorated at the time of film formation and over time. This is because the glass plate is heated in the formation of the film mainly composed of titanium dioxide, so that if the film mainly composed of silicon oxide does not exist, the alkali component in the glass plate is mainly composed of titanium dioxide. This is because thermal diffusion to the inside of the resulting film causes a deterioration phenomenon such as changing the crystal structure of titanium dioxide. In addition, the alkali component in the glass diffuses to the periphery over time, so that the deterioration gradually progresses as in the previous period. Therefore, by providing a film mainly composed of silicon oxide on the surface of the glass plate, the refractive index of the film mainly composed of titanium oxide is made to be 2.6 or more, and the refractive index is maintained for a long time. Can be.

On the other hand, a high refractive index film, that is, a film containing titanium oxide as a main component, has a refractive index of at least 2.6 at a wavelength of 350 to 800 nm and contains the above-mentioned dopant. When a dopant is contained, its content is preferably 0.02% by weight or less, and the thickness of the high refractive index film is preferably 100 nm or less. When this high refractive index film is made of titanium dioxide, it can have a crystal structure of anatase, brookite or rutile.
The crystal structure of a film containing titanium oxide as a main component varies depending on the film formation conditions. For example, when forming a film by the CVD method, anatase type is mainly generated under relatively low temperature conditions, and rutile type is mainly generated under relatively high temperature conditions. When a film is formed by a thermal decomposition method described later, the glass temperature immediately before the film formation is as high as 550 ° C. or higher, so that the crystal grain size becomes relatively large, and the refractive index at a wavelength of 350 to 800 nm is reliably set to 2.6 or more. Become.

As described above, first, a low-reflection film having an alkali barrier function is formed on a glass plate, a high-refractive index with a small deterioration of the crystal structure is formed thereon, and these films are alternately laminated in five layers. By doing so, the near-infrared blocking function can be exhibited more effectively than in the case of three layers. As a result, a visible light transmittance of 80 mm was obtained on a glass plate having a thickness of 3 mm.
% And a sunlight transmittance of 60% or less, a performance not achieved with the conventional transparent laminated film type near-infrared shielding glass.

As the glass plate, various commercially available glasses such as soda lime glass, borosilicate glass, alumina silicate glass and high silicate glass can be used.
In particular, soda lime glass formed by the float method is preferable because it has high transmittance and can be obtained at low cost. Soda lime glass exhibits various transmission colors by adding a small amount of a coloring component such as a transition metal element.
For example, a soda-lime glass exhibiting green, blue, bronze or gray transmitted light can be obtained by appropriately adjusting and adding divalent and trivalent iron and other coloring components. However, if the content of the coloring component is too high, the visible light transmittance of the near-infrared blocking glass is less than 80%, so that the visible light transmittance of the glass plate is preferably 85% or more. Incidentally, as the glass becomes thicker, the visible light transmittance decreases, and in the case of soda lime glass in which the transmitted light is clear, the thickness satisfying the visible light transmittance of 85% or more is 4 mm or less. When the thickness is 3 mm, the visible light transmittance is about 90% and the solar transmittance is about 85%.

The method for forming a film containing silicon oxide as a main component and a film containing titanium oxide as a main component is not particularly limited. For example, a sol-gel method, a solution immersion method, a thermal decomposition method (such as a chemical vapor deposition method or a spray method) or a vacuum evaporation method (such as a sputtering method) can be used. In the production of this near-infrared shielding glass, it is necessary to form a five-layer film, and if the film-forming process is complicated, the production cost increases significantly. Therefore, among the above-described manufacturing methods, the thermal decomposition method utilizing the heat of the glass ribbon proceeds in the pyrolysis method capable of continuously forming a film, particularly in the forming step of the glass ribbon when the glass plate is manufactured by the float method. Chemical vapor deposition (hereinafter referred to as “online CVD”)
Is the best. According to the online CVD method,
Since a five-layer film can be formed simultaneously with the formation of the glass plate, the production cost can be greatly reduced. In addition, since a film having a uniform thickness can be instantaneously formed over a large area, it is suitable for manufacturing window glass and roofing materials for buildings. Further, since the film is formed at a temperature higher than the softening point of the glass, defects such as pinholes (film missing) hardly occur.

When forming a film containing titanium oxide as a main component by the thermal decomposition method, the present inventors have set the temperature of the glass plate to 5 ° C.
It has been found that by setting the temperature to 50 ° C. or higher, the crystal growth is promoted to increase the grain size, and the refractive index of the film can be set to 2.6 or higher over the entire wavelength range of 350 to 800 nm. From this, if a film mainly composed of the second titanium oxide (fourth film counted from the glass plate surface) is formed while the glass ribbon temperature is 550 ° C. or higher in the online CVD method, In order to increase the refractive index, it is no longer necessary to perform high-temperature heating to carry out crystal transition, and the production cost can be suppressed.

Hereinafter, the online CVD method will be specifically described with reference to the drawings. As shown in FIG. 2, in this apparatus, the molten metal flows out of a melting furnace (float kiln) 11 into a tin float tank (float bath) 12 and moves at a predetermined distance from the surface of the glass ribbon 10 moving in a strip shape on the tin bath 15. A predetermined number of coaters 16 (three coaters 16a, 16b, 16c in the illustrated embodiment) are arranged. From these coaters, gaseous raw materials are supplied, and a film is continuously formed on the glass ribbon 10. By utilizing at least five coaters, the glass ribbon 10
On top, a film containing silicon oxide as a main component and a film containing titanium oxide as a main component can be continuously and alternately formed.
The glass ribbon 10 on which the five-layer film is formed is pulled up by the rollers 17 and sent to the annealing furnace 13. In addition, the glass plate annealed in the annealing furnace 13 is cut by a float-type general-purpose cutting device (not shown) into a glass plate having a predetermined size. In addition, 98% by volume of nitrogen and 2% by volume of hydrogen are supplied into the tin float tank space so that the inside of the tin float tank space is maintained at a slightly higher pressure than the outside of the tank. To hold.

From the first coater 16a, the third coater 16c and the fifth coater (not shown) along the flow of the glass ribbon, monosilane, disilane, trisilane, monochlorosilane, dichlorosilane, 1,2-dimethyl Silane, 1,1,2-trimethyldisilane, 1,
A silane-based material such as 1,2,2-tetramethyldisilane, tetramethylorthosilicate and / or tetraethylorthosilicate, oxygen, steam, dry air,
A gas mixture with an oxidizing material such as carbon dioxide, carbon monoxide, nitrogen dioxide and / or ozone is constantly blown toward the glass ribbon in a fixed amount. When the silane-based gas is used, it is preferable to use an unsaturated hydrocarbon gas such as ethylene, acetylene or toluene in combination in order to prevent the reaction of silane until the gas reaches the glass ribbon surface.

Further, from the second coater 16b and the fourth coater (not shown), titanium tetrachloride and / or
Alternatively, a constant amount of a mixed gas of a titanium raw material such as titanium isopropoxide and an oxidizing raw material such as oxygen, water vapor, dry air and / or ozone is constantly blown toward the glass ribbon.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The temperature of the glass plate was measured using a thermocouple at a position slightly upstream of the glass transport from the portion where the film was formed.

Example 1 A soda-lime glass plate having a thickness of 3 mm, which was cut into a size of 100 × 100 mm in advance, was placed on a mesh belt, passed through a heating furnace, and heated to about 600 ° C. While further transporting the heated glass plate, a mixed gas consisting of monosilane, oxygen and nitrogen was supplied from a coater installed above the glass transport path, and a 77 nm-thick silica film (first film: 2a) was molded. After the glass plate was gradually cooled, it was again placed on a mesh belt, passed through a heating furnace, and heated to 630 ° C. While further transporting the heated glass plate, a mixed gas comprising titanium isopropoxide (steam), oxygen and nitrogen is supplied from a coater provided above the glass transport path, and a 70 nm-thick oxidized film is formed on the silica film. A film containing titanium as a main component (second film: 3a) was formed. After the glass plate was gradually cooled, it was again placed on a mesh belt, passed through a heating furnace, and heated to 600 ° C. While further transporting this heated glass plate, a mixed gas consisting of monosilane, oxygen and nitrogen was supplied from a coater installed above the glass transport path, and a 154 nm-thick silica was deposited on the titanium oxide-based film. A film (third film: 2b) was formed. After the glass plate was gradually cooled, it was again placed on a mesh belt, passed through a heating furnace, and heated to 630 ° C. While further transporting the heated glass plate, a mixed gas comprising titanium isopropoxide (steam), oxygen and nitrogen is supplied from a coater installed above the glass transport path,
On the silica film, a 70 nm-thick film mainly composed of titanium oxide (fourth film: 3b) was formed. After the glass plate was gradually cooled, it was again placed on a mesh belt, passed through a heating furnace, and heated to 600 ° C. While further transporting the heated glass plate, a mixed gas consisting of monosilane, oxygen and nitrogen is supplied from a coater provided above the glass transport path, and a film having a thickness of 77
A silica film having a thickness of 5 nm (fifth film: 2c) was formed. The visible light transmittance and the sunlight transmittance of the glass plate having the five-layer film were measured according to JIS Z 8722. As a result, the visible light transmittance was 85.3% and the sunlight transmittance was 55.3%. there were. Further, in order to measure the refractive indexes of the above-mentioned film containing titanium oxide as a main component and the silica film, each film was formed on soda lime glass having a thickness of 3 mm. The deposition conditions are
The film containing titanium oxide as a main component was the same as the second film, and the thickness was 70 nm. The silica film was the same as the first film, and the thickness was 80 nm. For these films, the refractive index at a wavelength of 350 to 800 nm was measured using a spectroscopic ellipsometer. As a result, the film composed mainly of titanium oxide had a refractive index of 2.77 at a wavelength of 800 nm, and the refractive index monotonically increased as the wavelength became shorter, and was 3.73 at a wavelength of 350 nm. Similarly, the silica film also has a large refractive index on the short wavelength side, and has a wavelength of 80 nm.
The refractive index is 1.45 at 0 nm, and 1.48 at 350 nm.
Met.

(Comparative Example 1) Thickness 3 of the same composition as in Example 1
mm soda lime glass plate was prepared. A 77-nm-thick silica film, a 88-nm-thick titanium oxide-based film, a 154-nm-thick silica film, a 88-nm-thick titanium-oxide-based film, and a 77-nm-thick silica film on a glass plate Were formed in this order by an electron beam evaporation method. The visible light transmittance and the sunlight transmittance of the glass plate having the five-layer film are represented by J
As a result of measurement according to IS Z 8722, the visible light transmittance was 89.7% and the sunlight transmittance was 70.2%.
In addition, each of the film containing titanium oxide as a main component and the silica film was formed on soda lime glass having a thickness of 3 mm by electron beam evaporation. Note that a film containing titanium oxide as a main component has a thickness of 90 nm, and a silica film has a thickness of 80 nm.
And Using a spectroscopic ellipsometer, the wavelength
The refractive index up to 800 nm was measured. The refractive index of the film containing titanium oxide as a main component was 2.17 at a wavelength of 800 nm, and the refractive index monotonically increased as the wavelength became shorter, and was 2.68 at a wavelength of 350 nm. Similarly, the silica film also increased its refractive index at a short wavelength, showing a refractive index of 1.45 at a wavelength of 800 nm and 1.47 at a wavelength of 350 nm.

(Comparative Example 2) Five layers were formed in the same manner as in Example 1 except that the forming conditions of the second film and the fourth film were set such that the surface temperature of the glass plate was 500 ° C and their film thickness was 88 nm. A glass plate with a membrane was produced. As a result of measuring the visible light transmittance and the sunlight transmittance of this glass plate according to JIS Z 8722, the visible light transmittance was 87.7% and the sunlight transmittance was 66.8%. Further, in order to measure the refractive index of the film containing titanium oxide as a main component, this film was formed on soda lime glass having a thickness of 3 mm under the above-mentioned forming conditions of the second film. Wavelength 35 using a spectroscopic ellipsometer
As a result of measuring the refractive index at 0 to 800 nm, this film was found to have a wavelength of 8 nm.
The refractive index was 2.18 at 00 nm, and monotonically increased as the wavelength became shorter, and was 2.73 at a wavelength of 350 nm.

The following can be understood from the comparison between the above-described embodiment and the comparative example. It is understood that by increasing the refractive index of the film containing titanium oxide as a main component, the visible light transmittance of the electromagnetic wave shielding film composed of five layers can be increased and the sunlight transmittance can be suppressed. When a film mainly composed of titanium oxide is formed by a thermal decomposition method, if the surface temperature of the glass plate is set to 550 ° C. or more, the refractive index at a wavelength of 350 to 800 nm can be reliably set to 2.6 or more. I understand.

[0022]

As described above, according to the present invention, a film mainly composed of titanium oxide having a refractive index of 2.6 or more at a wavelength of 350 to 800 nm can be obtained by a simple method. Then, by alternately laminating five low-refractive-index films containing silicon oxide as a main component and high-refractive-index films containing this titanium oxide as a main component on a glass plate, the visible light transmittance is high, and Near-infrared shielding glass with low sunlight transmittance can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the near-infrared shielding glass of the present invention.

FIG. 2 is a view schematically showing an apparatus capable of manufacturing the near-infrared shielding glass of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass plate 2 Film containing silicon oxide as a main component (low refractive index film) 3 Film containing titanium oxide as a main component (high refractive index film) 10 Glass ribbon 11 Melting furnace 12 Tin float tank 13 Annealing furnace 15 Tin bath 16 Coater 17 roller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kubota Teruhobo 4-7-28 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Inside Nippon Sheet Glass Co., Ltd. (72) Momoe Kokubo 4-7-1, Kitahama, Chuo-ku, Osaka City, Osaka Prefecture No. 28 Nippon Sheet Glass Co., Ltd. F-term (reference) 2H048 FA05 FA12 FA13 FA24 GA04 GA09 GA12 GA33 GA60 4F100 AA20B AA20D AA21C AA21E AG00A BA05 BA10A BA10B EH66C EH66E JD10 JN01 JN18B JN18C JN18Y00 EJE YE01Y01E01E01E01E01 GA02 GA04 GA12

Claims (2)

[Claims] 1. A low-refractive-index film, a high-refractive-index film on a glass plate,
A low-refractive-index film, a high-refractive-index film, and a low-refractive-index film are laminated in this order, and when the glass plate is 3 mm, the visible light transmittance is 80% or more, and the sunlight transmittance is 60% or less, wherein the low-refractive-index film is a film containing silicon oxide as a main component, and the high-refractive-index film is mainly composed of titanium oxide, and has a refractive index of 2.6 at a wavelength of 350 to 800 nm. The near-infrared shielding glass which is the above film. 2. The method according to claim 1, wherein the film containing titanium oxide as a main component is formed by a thermal decomposition method.
The near-infrared shielding glass according to claim 1, which is not lower than ° C.