JP6703267B2 - Gray tone low emissivity glass - Google Patents

Description

The present invention relates to low-emission glass having a low-emission film on the glass surface, and more particularly to low-emission glass exhibiting a gray color tone.

2. Description of the Related Art In recent years, window glass using low-emission glass formed with a low-emissivity laminated film (hereinafter, also referred to as a low-emission film) is becoming popular for the purpose of improving cooling and heating efficiency. This low-emission glass takes visible light into the room, and while satisfying the daylighting properties required for window glass, the low-emission film reflects light in the near-infrared region to the infrared region. The temperature rise can be suppressed. In addition, since the heat transfer from the room to the outdoors is blocked, the ability to keep the room warm and insulate is high.

As the low-emission film as described above, a film using a metal layer containing Ag as a main component is often used. For example, in Patent Document 1, the sum of the geometrical thicknesses of the second layer and the fourth layer, which are metal layers containing Ag as a main component, is 22 to 29 nm, and the geometrical thickness of the second layer is the fourth layer. The thickness is 0.3 to 0.8 times, the total optical thickness of the first, third, and fifth dielectric layers is 220 to 380 nm, and the optical thickness of the third layer is 140 to 200 nm. Disclosed is a glass laminate for a window in which the optical thickness of one layer is 0.4 to 1.5 times the optical thickness of the fifth layer and the reflectance in the near infrared region is improved. In the example, the window glass laminate has a visible light transmittance of 70% or more and a solar radiation transmittance of about 33 to 40%.

As described above, the low-emissivity film having a visible light transmittance of 70% or more has a daylighting property, but on the other hand, for example, in an office building, sunlight or reflected light from an adjacent building is dazzling, which causes glare. For the purpose of reducing (glare), there is a demand for a window material having a visible light transmittance lower than the above 70%, and as such a window material, a low-emission glass of a type that emphasizes heat shielding is important. used. As a type that attaches importance to the heat-shielding property, a low-radiation glass having a visible light transmittance of less than 70% and a solar radiation transmittance of 40% or less is incorporated into a double-glazing unit, and the solar heat gain rate of the double-layer glass is measured. Has been studied for a double-layer glass having a value of 0.40 or less.

For example, in Japanese Patent Application Laid-Open No. 2004-163242, an absorption layer that absorbs solar radiation to some extent is provided on a transparent plate, and a laminated film including a layer containing Ag as a main component and a transparent dielectric layer as described above is formed on the absorption layer. A shielding translucent plate is disclosed. In the examples, the solar radiation transmissivity of the single plate of the solar radiation translucent plate is 21 to 35% or less, and the solar heat gain coefficient of the multi-layer glass is 0.29 to 0.40.

Further, for example, in Patent Document 3, a first dielectric layer, a first Ag layer, a first barrier layer, a first absorption layer, and a second dielectric layer are formed on a substrate. A second Ag layer, a second absorber layer, a third dielectric layer and optionally a topcoat layer, either the first absorber layer or the second absorber layer being arbitrarily selected Low emissivity coatings are disclosed. The low emissivity coating achieves chemical and mechanical durability and attractive appearance quality by providing an absorber layer on the barrier layer.

The barrier layer is generally a layer provided on the surface of the Ag layer. There is a potential problem that the Ag layer deteriorates as a low radiation film when oxidized. However, when a film above the Ag layer is formed by sputtering using a reactive gas containing oxygen, the lower Ag layer is also oxidized. Therefore, a barrier layer is provided on the surface of the Ag layer using an inert gas, and an upper layer is formed on the barrier layer. Normally, the barrier layer is oxidized by the reactive gas containing oxygen when forming the upper layer.

As the barrier layer as described above, a Zn film containing Al (hereinafter sometimes referred to as “ZnAl”), a Ti film, a Cr film, a stainless steel (Fe—Ni—Cr alloy) film, and Ni and Cr Alloy films and the like are known (for example, Patent Documents 3 to 5).

JP, 2010-195638, A Japanese Patent Laid-Open No. 11-228185 Japanese Patent Publication No. 2008-540320 JP, 7-187727, A JP, 11-343146, A

In recent years, low-emission glass using a low-emission film having two Ag layers as described above has been attracting attention as a window material for buildings. Conventionally, in the case of a building such as a building in which concrete is used for the wall surface, glass having clear or low-saturation blue, green, yellow or other transparent colors and blue or green or other reflective colors is used. In addition, the visible light transmittance was 60% or more, and it had an appropriate daylighting property. In addition, from the viewpoint of the design of the building, in order to give the appearance quality a distinctive color, the saturation of the reflection color such as blue and green is increased and the reflectance is also increased. Glass having a visible light transmittance of about 50 to 60% and a reflectance of 10 to 20% was used. On the other hand, as a glass that seeks a more sense of unity with the wall surface, there is an increasing demand for a glass that has a transmitted color with reduced saturation and lightness, and a reflectance and a reflected color that do not claim too much.

As one method of obtaining the above glass, the visible light transmittance when the thickness of the glass plate is 3 mm is as low as 50% or less, and the transmitted color is an intermediate color (for example, CIE L ^* a ^* b ^* chromaticity). Glass with a gray color tone in which a ^* and b ^* of transmitted light in the coordinate diagram are in the range of -5 to +2 respectively) can be mentioned. In order to lower the visible light transmittance, it is sufficient to increase the thickness of the Ag layer, but in that case, the reflectance increases and glare increases. However, there is a problem in that the appearance quality is impaired by the remarkable appearance of the tint, or the redness of the reflected color when viewed obliquely.

Therefore, the object of the present invention is to obtain a low-emission glass exhibiting a gray color tone with good appearance quality.

As a result of diligent studies by the inventors of the present invention on the above problems, the low-emission glass having appropriate lighting and exhibiting a gray color tone has a high reflectance of the glass surface of the low-emission glass. It turns out that there is a tendency to fall. Further investigation based on the obtained findings revealed that the barrier layer formed on the outermost Ag layer of the low emissive film has an absorption rate in the visible range to the infrared range (hereinafter referred to as "solar absorption rate"). It has been found that it is possible to make the reflectance of the glass surface of the low-emission glass to be less than 10% by setting (in some cases) within a specific range. Further, it was also found that when the solar radiation absorptivity of the barrier layer formed on the Ag layer on the glass plate side exceeds a specific amount, the reflectance of the glass surface becomes high on the contrary.

Therefore, the present invention provides a low-emission glass in which a low-emission film exhibiting a gray color tone is formed on the surface of the glass plate, and the low-emission film has a first dielectric layer and a first Ag layer in order from the surface of the glass plate. , The first barrier layer, the second dielectric layer, the second Ag layer, the second barrier layer, and the third dielectric layer, and the first barrier layer has a solar radiation absorptivity of 0. ˜6%, the second barrier layer has a solar radiation absorptivity of 20 to 35%, and the low emissivity glass has a glass surface reflectance of less than 10%, which is a gray tone low emissivity glass.

According to the present invention, it is possible to obtain a low-emission glass exhibiting a gray color tone having a good appearance quality.

It is a cross-sectional schematic diagram showing one Embodiment of the low emission film|membrane of this invention. It is a cross-sectional schematic diagram showing one Embodiment of the double glazing of this invention. It is the figure which showed a ^* and b ^* of the transmitted light of an Example and a comparative example. It is the figure which showed a ^* and b ^* of the reflected light of the glass surface of an Example and a comparative example.

The present invention provides a low-emission glass in which a low-emission film exhibiting a gray color tone is formed on the surface of the glass plate, wherein the low-emission film comprises, in order from the glass plate surface, a first dielectric layer, a first Ag layer, It has a first barrier layer, a second dielectric layer, a second Ag layer, a second barrier layer, and a third dielectric layer, and the solar radiation absorptivity of the first barrier layer is 0 to 0. 6%, the second barrier layer has a solar absorptivity of 20 to 35%, and the low-emission glass has a glass surface reflectance of less than 10%, which is a gray tone low-emission glass.

1: Explanation of terms (gray color)
The "gray color tone" in the present invention means that the visible light transmittance obtained by the method according to JIS R3106 (1998) is 50% or less when the thickness of the glass plate is 3 mm, and according to JIS Z8781-4. In the values represented by the CIE L ^* a ^* b ^* chromaticity coordinate diagram of the transmission color of the low-emission glass plate calculated as above, a ^* and b ^* are in the range of -5 to +2, respectively. And

(Solar absorption rate)
The solar absorptance of the entire low emissive film was calculated by the method based on JIS R3106 (1998). In addition, it is difficult to measure the solar absorptivity of only the barrier layer from the low-emission film that has been formed, so a glass plate/barrier layer/dielectric layer is formed and the solar absorptivity of the obtained sample is measured. The solar radiation absorptance of the barrier layer was obtained by removing the solar radiation absorptance of the glass plate and the dielectric layer from the obtained solar radiation absorptivity. The film forming conditions and the glass plate, barrier layer and dielectric layer used at this time were the same as those of the low emission film to be produced.

(Glass surface reflectance)
The reflectance of the glass surface of the low-emission film (hereinafter, also referred to as “glass surface reflectance”) was calculated by a method according to JIS R3106 (1998).

(Physical film thickness)
The physical film thickness has the same meaning as a commonly used film thickness and is simply a thin film thickness. In the present specification, from the product of the film thickness of a single-layer film produced under the same film-forming conditions as the production of the low-emissivity film and the transport speed of the substrate, the film-forming rate at the time of producing the single-layer film is determined. It is a value obtained by calculating the film thickness of the corresponding layer of the low emissivity film using the film formation rate.

(Optical film thickness)
The optical film thickness is a value represented by a product of a physical film thickness and a refractive index, and in the present specification, a refractive index at a wavelength of 550 nm of a single-layer film manufactured under the same film forming conditions as when manufacturing a low radiation film. It is a value calculated from the product of the film thickness and the film thickness. The refractive index in the present invention is obtained by measuring the transmittance and reflectance of the monolayer film with a spectrophotometer (U-4000, manufactured by Hitachi, Ltd.), and calculating from the obtained values by optical simulation (Reflectance-transmittance method). did.

(Description of membrane)
In the present specification, “ZnAl” means a film in which Zn is mixed with Al, and does not mean that Zn and Al are mixed at a ratio of 1:1. The Al content is appropriately selected, but may be, for example, 1 to 10 wt %. Further, a film in which ZnAl is oxidized is described as “AZO”, but this does not mean that Zn:Al:O becomes 1:1:1.

Further, “NiCr” indicates an alloy film mainly containing Ni and Cr, and does not indicate that Ni and Cr are mixed at a ratio of 1:1. The contents of the above components may be appropriately selected, but for example, the Ni content may be 55 to 85 wt% and the Cr content may be 10 to 25 wt %. It may also contain other elements such as Fe.

Further, "stainless steel" particularly refers to a mixture of Fe, Cr, and Ni, and may be referred to as "SUS" hereinafter. The contents of the above-mentioned three components may be appropriately selected. For example, Fe may be contained in 50 to 80 wt%, Cr may be contained in 10 to 25 wt%, and Ni may be contained in 0 to 20 wt%. It may also contain other elements such as Mn and Mo.

In addition, “ZnSn” indicates a film in which Sn is mixed with Zn, and does not indicate that Zn and Sn are mixed at a ratio of 1:1. The Sn content is appropriately selected, but may be, for example, 30 to 70 wt %. A film in which ZnSn is oxidized is described as "ZnSnO", but this does not mean that Zn:Sn:O becomes 1:1:1.

2: Low Emission Glass A preferred embodiment of the low emission film of the present invention is shown in FIG. The low emissivity film 2 is formed on the glass plate 1 and may have a lower emissivity than the ordinary glass plate 1. Further, for example, the low emissivity glass 3 on which the low emissivity film 2 is formed may have a vertical emissivity of 0.3 or less measured in accordance with JIS R3106 as a “low emissivity film”. In addition, any layer may be formed between the low-emission film and the glass plate or on the surface of the uppermost layer of the low-emission film.

Further, the gray tone low emission glass 3 of the present invention can have a glass surface reflectance of the low emission glass 3 of less than 10%. Normally, the low-emission glass 3 is used as a multi-layer glass, but the low-emission film 2 of the low-emission glass 3 is arranged so as not to come into direct contact with outdoors or indoors. That is, since the low-emission glass 3 comes into contact with the outdoors or indoors on the glass surface, it is possible to suppress glare by reducing the reflectance of the glass surface.

The low-emissivity glass of the present invention may have a low reflectance, and when viewed in a general construction environment, the transmitted color and the reflected color of the glass surface are easily recognized and easily recognized. Here, green is generally known as a color having a high relative luminous efficiency, and when the reflected color actually has a green tint, the green is strongly recognized, and together with the transmitted color, the green tint is seen as a whole. It was newly found that it is easy to see a gray tone with a tint. Further, when the reflection color is reddish, the color often becomes heterogeneous in the construction environment, and the tint becomes noticeable, making it difficult to achieve harmony with the environment. Further, when the reflection color is yellowish, yellow has a complementary color relationship with blue, and it tends to be seen as a clearly conspicuous color with respect to blue in the sky. As a result of the inventors' investigations on the above problems, it was found that even if the reflection color is in the range showing a pale blue color, it is not noticeable even when combined with the gray color of the transmission color, and a gray tone is exhibited as a whole. It was

Therefore, in the gray-tone low-emission glass 3 of the present invention, the reflection color of the glass surface is represented by CIE L ^* a ^* b ^* chromaticity coordinate diagram, where a ^* is -5 to 0 and b ^* is -12 to -5. Is preferred. It is preferable that a ^* is in the range of -5 to 0 because it is possible to suppress the reflected color of the glass surface from becoming red or green. Further, b ^* is preferably within the range of -12 to -5. Generally, the larger b ^* becomes negative, the more blue it becomes, but when b ^* is less than -12, the bluish reflection is strongly recognized, and when viewed in the construction environment, the impression is bluer than gray. May become stronger. Since blue has a low relative luminous efficiency, if it is within the above range, the bluish reflected color is not conspicuous, and the low-emission glass as a whole can exhibit a gray color tone. Further, preferably b ^* may be -10 to -5. Also, the upper limit of b ^* is set to -5, but this is to prevent the green or red tint from being stronger than blue due to the balance with a ^*, and the absolute value of a ^* should be sufficient. When it is small (a ^* is close to 0), it may exceed -5 as long as it is not yellowish.

(Glass plate)
The glass plate 1 to be used is not particularly limited, but for example, commonly used soda lime glass, alkali-free glass, highly transparent glass, air-cooled tempered glass, chemically tempered glass, reticulated glass, lined glass. It is possible to use borosilicate glass, low expansion glass, zero expansion glass, low expansion crystallized glass, zero expansion crystallized glass, and the like.

In addition to the glass plate 1 described above, a transparent substrate such as a resin may be used, and examples thereof include polyethylene terephthalate resin, polyethylene naphthalate resin, polyether sulfone resin, polycarbonate resin, polyvinyl chloride resin and the like.

The thickness of the glass plate 1 is not particularly limited, but may be 3 to 19 mm which is generally used as architectural glass. Further, the visible light transmittance and the solar radiation transmittance may be affected by the thickness of the substrate, and the transmittance tends to decrease as the thickness of the substrate increases. For example, comparing a 3 mm glass substrate used as the architectural glass and a 6 mm glass substrate, the visible light transmittance of the 3 mm glass substrate is higher by about 0.5 to 1.5%.

(Dielectric layer)
The dielectric layers 11a, 11b, 11c are transparent thin films of an oxide, a nitride, or an oxynitride containing at least one selected from the group consisting of Al, Si, Ti, Zn, In, and Sn. preferable. The first layer 11a, the second layer 11b, and the third layer 11c of the dielectric layer are for adjusting the reflection color of the low-emissivity film, and the respective film thicknesses may be appropriately adjusted according to desired characteristics. Each layer may be a laminate of two or more kinds of films. Note that it is preferable to arrange a film having a zinc oxide structure at a position in contact with the Ag layer because the crystallinity of the Ag layer is improved.

In order for the low-emission glass to have a gray color tone, the first dielectric layer 11a has a thickness of 60 to 120 nm, the second dielectric layer 11b has a thickness of 160 to 240 nm, and the third dielectric layer 11c has a thickness of 25. It is preferable that the thickness is ˜65 nm. More preferably, the first dielectric layer 11a may have a thickness of 80 to 100 nm, the second dielectric layer 11b may have a thickness of 180 to 210 nm, and the third dielectric layer 11c may have a thickness of 30 to 50 nm.

The first dielectric layer 11a acts as a base layer of the first Ag layer 12a and improves the adhesion between the first Ag layer 12a and the glass plate 1. It is preferable to use ZnO, SnO ₂ , ZnSnO, Si ₃ N ₄ and TiO ₂ . ZnO, SnO ₂ , ZnSnO, and TiO ₂ may each be an oxide film or an alloy oxide film containing an optional third component. Further, Si ₃ N ₄ may be a nitride film or an alloy nitride film containing an optional third component.

The second dielectric layer 11b is formed on the first barrier layer 13a, and is a layer that greatly affects the reflection color and the solar radiation transmittance of the low emissivity film 2. The second dielectric layer 11b has an oxide dielectric. For example, ZnO, SnO ₂ , ZnSnO, TiO _{2 and the} like can be mentioned. When forming the second dielectric layer 11b, it is possible to simultaneously oxidize the lower first barrier layer 13a by forming the film in a reactive gas atmosphere containing oxygen.

The third dielectric layer 11c is formed on the second barrier layer 13b, and is a layer that interacts with other dielectric layers to adjust the reflection color and the solar radiation transmittance. The dielectric layer 11c of the third, as in the first dielectric layer _11a, ZnO, SnO 2, ZnSnO, preferable to use _Si 3 _{N 4} and TiO _2. The third dielectric layer 11c is preferably two or more layers, and the uppermost layer 14 formed on the outermost surface side is preferably a film that improves the moisture resistance and durability of the low radiation film 2. For example, a transparent thin film of an oxide, a nitride, or an oxynitride containing at least one selected from the group consisting of Al, Si, and Ti can be mentioned. Further, it is preferable that the physical film thickness is 3 to 20 nm because the moisture resistance and the durability are improved.

(Ag layer)
The Ag layer is a layer having a function of reflecting infrared rays. Further, it is a layer containing Ag as a main component and is an Ag film or an Ag alloy film containing Ag as a main component. The Ag alloy film may contain a metal such as palladium, gold, platinum, nickel, or copper in the range of 5 wt% or less. Further, the "main component" means that Ag is contained in an amount of 90 wt% or more.

In the present invention, the total physical film thickness of the first Ag layer 12a and the second Ag layer 12b is preferably within the range of 12 to 22 nm. More preferably, it may be 13 nm to 19 nm. By setting the thickness of the Ag film within the above range, it is possible to have both a good appearance and a low radiation function. Further, by setting the film thickness of the second Ag layer 12b≧the film thickness of the first Ag layer 12a, it is possible to suppress the reflected color of the glass surface from being reddish or to suppress the saturation of the reflected color. Is possible.

(Barrier layer)
A barrier layer is formed on each of the first Ag layer 12a and the second Ag layer 12b for the purpose of preventing deterioration of Ag during the manufacturing process. The present invention obtains a gray color tone and a good appearance quality by using a layer having a solar absorptance of 20 to 35% as the second barrier layer. If necessary, a plurality of films may be laminated on both the first barrier layer 13a and the second barrier layer 13b, or two or more kinds of metal components may be mixed in one film.

The first barrier layer 13a preferably contains, as a component, at least one selected from the group consisting of oxidized ZnAl, Ti, NiCr, Nb, and stainless steel. The first barrier layer 13a is oxidized when the second dielectric layer 11b is formed, and the solar absorptivity is reduced. At this time, it is sufficient that the solar radiation absorption rate is 6% or less, and it is not necessary to completely oxidize.

The film thickness of the first barrier layer 13a may be a thickness that allows oxidation, nitriding, and oxynitriding, and may be appropriately selected according to the components and devices used. For example, in the examples of the present specification, the physical film thickness is set to 7.7 nm or less when the ZnAl film is used as the first barrier layer 13a, and about 2.6 nm or less when the Ti film is used. The appropriate film thickness range varies depending on the apparatus and film forming conditions.

The second barrier layer 13b preferably has one which is not oxidized or nitrided and is selected from the group consisting of Ti, NiCr, Nb and stainless steel. Further, if the solar absorptance is in the range of 20 to 35%, it may be partially oxidized or nitrided. If a reactive gas is used to form the third dielectric layer 11c, the third dielectric layer 11c side of the second barrier layer 13b may be oxidized or nitrided by the reactive gas. However, as a result of studies by the inventors, it was found that the thickness at which the second barrier layer 13b is oxidized or nitrided has an upper limit value, and if the film thickness is thicker than the upper limit value, the solar radiation absorption rate is increased. It becomes possible. The optimum film thickness of the second barrier layer 13b varies depending on the device and the type of film, but for example, in the examples of the present specification, when the Ti film is used, the physical film thickness is set to about 5 to 6 nm.

The sum of the optical thicknesses of the first, second and third dielectric layers is 300 to 340 nm, the physical thickness of the first Ag layer is 6 to 10 nm, and the physical thickness of the second Ag layer is It is preferably 8 to 10 nm. By setting each film thickness within the above range, b ^* of the reflection color on the glass surface can be set within the range of -12 to -5.

3: Method for producing low-emission film The method for producing the low-emission glass of the present invention will be described below.

The low-radiation transparent glass of the present invention is preferably formed by a sputtering method, an electron beam evaporation method, an ion plating method, or the like, but the sputtering method is suitable because it is easy to ensure productivity and uniformity.

The low-emissivity film is formed by the sputtering method while the glass plate 1 is being conveyed through the inside of the apparatus in which the sputtering target serving as the material of each layer is installed. At this time, the atmosphere gas used for sputtering is introduced into the vacuum chamber for film formation provided in the apparatus, and by applying a negative potential to the target, plasma is generated in the apparatus to perform sputtering. To do.

Further, the method for obtaining the desired film thickness is not particularly limited because it depends on the type of the sputtering apparatus, but a method for controlling the film thickness by changing the film formation rate by adjusting the power input to the target and the conditions of introduced gas and A method of controlling the film thickness by adjusting the substrate transport speed is widely used.

When forming each of the dielectric layers, the target to be used may be either a ceramic target or a metal target. In any case, the gas condition of the atmosphere gas to be used is not particularly limited, and the gas species and the mixing ratio may be appropriately determined from Ar gas, O ₂ gas, N ₂ gas and the like according to the target film. Further, the gas introduced into the vacuum chamber may include any third component other than Ar gas, O ₂ gas, and N ₂ gas.

When forming the second dielectric layer 11b, in a reactive gas atmosphere such as O ₂ gas, N ₂ gas or CO ₂ gas so that the first barrier layer 13a can be oxidized or oxynitrided. It is preferable to form the film.

When forming an Ag layer, an Ag target or an Ag alloy target is used as a target to be used. Ar gas is preferably used as the atmosphere gas introduced at this time, but different kinds of gas may be mixed as long as the optical characteristics of the Ag film are not impaired.

When the first barrier layer 13a is formed, the target to be used may be appropriately selected, and the atmosphere gas to be introduced may be an inert gas such as Ar. Further, at this time, the first barrier layer 13a has a film thickness that allows oxidation and nitridation in a post process as in the conventional case.

When forming the second barrier layer 13b, one layer selected from the group consisting of Ti, NiCr, Nb and SUS is formed in an inert gas atmosphere. Further, the second barrier layer 13b is preferably not thickly oxidized even after the formation of the upper dielectric film, and is preferably thick in order to leave a portion existing as a metal component. When an inert gas is used when forming the body layer 11c, the thickness may be such that the solar radiation absorptivity is 20 to 35%.

A DC power supply, an AC power supply, a power supply that superimposes AC and DC, etc. can be used as the plasma generation source, but if abnormal discharge is likely to occur when forming the dielectric layer, apply a pulse to the DC power supply. It is preferable to use the above-mentioned power source or AC power source.

4: Double glazing In the present invention, the low radiation glass 3 may be used as a single plate or a laminated glass, but as shown in FIG. 2, when it is used as a double glazing, the low radiation film 2 can be protected. It is preferable because it is possible. That is, the present invention is a multilayer glass in which the gray tone low-emission glass described above and a glass plate are integrated via a spacer, and the surface of the low-emission glass on which the low-emission film is formed is the spacer side. It is a multi-layer glass characterized in that

When used as a multi-layer glass, the surface of the low-emission glass 3 on which the low-emission film 2 is formed is opposed to another glass plate 1 at a predetermined interval so as to form a hollow layer 23, and the peripheral portion is a spacer 21 or a seal. The material 22 is used for sealing. The hollow layer 23 is filled with an inert gas such as Ar, He, Ne, Kr, Xe, dry air, N ₂ or the like, and normally dry air is used, but the heat insulation performance and sound insulation performance are further improved. Ar gas, Ne gas or the like may be used for the purpose.

The spacer 21 has a desiccant inside and is fixed between at least two glass plates via a sealing material (not shown) such as butyl rubber or silicone, and is made of a lightweight aluminum material or resin material. Be done. A portion surrounded by the spacer 21, the low-emission glass 3, and the glass plate 1 is a hollow layer 23, and the heat insulating property of the double-glazing can be changed depending on the thickness of the hollow layer 23 and the type of gas to be enclosed. It is possible.

Examples and comparative examples of the present invention will be shown below. Table 1 shows the configurations of the low-emissivity films of Examples and Comparative Examples. Regarding the notation of the barrier layer, the type and film thickness of the film immediately after the barrier layer is formed are described. Actually, when forming the upper dielectric film, a part or the whole film from the interface on the dielectric layer side is shown. It is in an oxidized state.

In each of the examples and comparative examples, film formation was performed on a soda lime glass having a thickness of 3 mm by using a magnetron sputtering device. Further, in any of the examples and the comparative examples, the glass plate and the film were not heated, and were not particularly heated except when the temperature of the glass plate was increased due to sputtering during film formation.

The thickness of each layer was adjusted to the film thickness shown in Table 1 by adjusting the transportation speed of the glass plate. In addition, as the above-mentioned transportation speed, a speed calculated for each type of film after forming a single-layer film was used.

(Examples 1 to 4, Comparative Examples 1 and 3)
First, the glass plate 1 was held by the substrate holder, and a desired target was placed in each vacuum chamber. A magnet is arranged on the back side of the target. Next, the inside of the vacuum chamber was evacuated by a vacuum pump.

Next, the first dielectric layer 11a was deposited on the glass plate 1. A Zn target (hereinafter sometimes referred to as ZnAl) containing 2 wt% of Al was used as a target, and 1100 W of power was applied to the ZnAl target from a DC power source through a power cable. At this time, while continuously operating the vacuum pump, argon gas was introduced into the vacuum chamber at 20 sccm and oxygen gas was introduced at 40 sccm, and the pressure was adjusted to 0.4 Pa. From the above, a ZnAlO film was obtained.

Next, the first Ag layer 12a was formed on the ZnAlO film. An Ag target was introduced into the target, an argon gas was introduced at 45 sccm as an atmosphere gas in the vacuum chamber, and the pressure was adjusted to 0.3 Pa. The power supplied from the DC power source was 300W. From the above, an Ag film was obtained.

Next, the first barrier layer 13a was formed on the Ag film. A ZnAl target in which 4 wt% of Al was added to the target, and argon gas was introduced at 100 sccm as an atmosphere gas in the vacuum chamber, and the pressure was adjusted to 0.7 Pa. The electric power supplied from the DC power source was 180W. From the above, a ZnAl film was obtained.

Next, a ZnAlO film was formed as the second dielectric layer 11b on the first barrier layer 13a. The film forming conditions were the same as those for the first dielectric layer 11a, except that the transport speed was adjusted to obtain a desired film thickness.

Next, the second Ag layer 12b was formed on the ZnAlO film. The film forming conditions were the same as those for the first Ag layer 12a, except that the transport speed was adjusted to obtain a desired film thickness.

Then, a Ti film was formed as a second barrier layer 13b on the Ag film. The target was a Ti target, and argon gas was introduced at 80 sccm as the atmospheric gas in the vacuum chamber, and the pressure was adjusted to 0.6 Pa. Further, the electric power supplied from the DC power source was 330 W. From the above, a Ti film was obtained.

Next, a ZnSnO film was first formed as a third dielectric layer 11c on the second barrier layer 13b. A ZnSn target containing 50 wt% of Sn added to the target, an argon gas of 10 sccm and an oxygen gas of 50 sccm were introduced as the atmosphere gas in the vacuum chamber, and the pressure was adjusted to 0.4 Pa. In addition, the power supplied by the DC power supply was set to 1100W. From the above, a ZnSnO film was obtained.

Next, a TiO ₂ film was formed on the ZnSnO film as the uppermost layer 14. A Ti target was used as a target, an argon gas of 40 sccm and an oxygen gas of 40 sccm were introduced as the atmosphere gas in the vacuum chamber, and the pressure was adjusted to 0.5 Pa. The power supplied by the DC power supply was 3050W. From the above, a TiO ₂ film was obtained.

(Example 5, Comparative Example 4)
A low radiation film was obtained in the same manner as in Example 1 except that Ti was used for the first barrier layer 13a and the transport speed was adjusted to obtain the film thickness as shown in Table 1. In forming the first barrier layer 13a, a Ti target was used as a target, an argon gas was introduced as the atmospheric gas in the vacuum chamber at 80 sccm, and the pressure was adjusted to 0.6 Pa. Further, the electric power supplied from the DC power source was 330 W.

(Comparative example 2)
A low emission film was obtained in the same manner as in Example 1 except that ZnAl was used for the second barrier layer 13b and the transport speed was adjusted to obtain the film thickness as shown in Table 1. The second barrier layer 13b was formed by introducing a ZnAl target in which 4 wt% of Al was added to the target, introducing argon gas at 80 sccm as an atmospheric gas in the vacuum chamber, and adjusting the pressure to 0.7 Pa. The electric power supplied from the DC power source was 180W.

(Optical characteristics of low emission glass)
The optical characteristics of the low-emission glass obtained in the above Examples and Comparative Examples were measured using a self-recording spectrophotometer (U-4000 manufactured by Hitachi, Ltd.). The visible light transmittance, the visible light reflectance of the glass surface, and the solar absorptance were calculated according to JIS R3106 (1998). Further, the transmission color of the low-emission glass and the reflection color of the glass surface were calculated based on JIS Z8781-4. The obtained results are shown in Table 2. The transmission colors a ^* and b ^* of the examples and the comparative examples are shown in FIG. 3, and the reflection colors a ^* and b ^* of the glass surface are shown in FIG.

(Evaluation of solar radiation absorption rate of barrier layer)
Since it is difficult to calculate the solar absorptivity of only the barrier layer portion by evaluating the solar absorptivity of the low-emission glass, the solar absorptivity of the barrier layer was measured by the following method.

First, a barrier layer was formed on a soda lime glass having a thickness of 3 mm by the same method as in the examples and comparative examples, and a dielectric layer was formed on the barrier layer to prepare a measurement sample. That is, a laminated body of glass/first barrier layer 13a/second dielectric layer 11b, and glass/second barrier layer 13b/third dielectric layer 11c is prepared, and the film of each barrier layer is formed. The type and film thickness were the same as those in the examples and comparative examples.

Regarding AZO and ZnSnO used in this example and the comparative example, even if the thickness of the dielectric layer is large, the influence on the solar radiation absorptivity of the barrier layer is small in the range where the physical thickness is 10 nm or more. I understood it. Therefore, the physical film thickness of each of the second dielectric layer 11b and the third dielectric layer 11c is set to 20 nm. The outermost layer of the third dielectric layer 11c was not formed.

Next, the solar radiation absorptivity of the obtained measurement sample was measured, and the value obtained by removing the solar radiation absorptance of the glass and the dielectric layer from the measured value was defined as the solar radiation absorptivity of the barrier layer. The solar absorptances of the glass and the dielectric layer are described in Reference Example 1 below. The obtained solar radiation absorption rate is shown in Table 3.

(Reference example 1)
In order to obtain the solar radiation absorptance of only the glass plate and the dielectric layer, a sample in which a dielectric layer was directly formed on a glass plate of soda lime glass was prepared under the same conditions as in the examples and comparative examples. When the physical film thickness of the dielectric layer was 20 nm, the solar radiation absorptance of the glass plate and the dielectric layer was 6.0% for AZO and 5.9% for ZnSnO. These values were used when calculating the solar radiation absorption rate of the barrier layer.

(Reference example 2)
The effect of the film thickness of the dielectric layer on the solar absorptivity of the barrier layer was investigated by the same method as the method for measuring the solar absorptivity of the barrier layer. As a measurement sample, a Ti film having a thickness of 2.4 nm was formed as a barrier layer on a soda-lime glass having a thickness of 3 mm, and a ZnSnO film having a physical film thickness was changed to 10 nm, 20 nm, and 30 nm as a dielectric layer thereon. Three types were prepared. The solar radiation absorptance of the barrier layer of the obtained sample was 4.1 to 4.6%, which was not significantly different.

From the above, in the range where the Ti film is 2.4 nm and the dielectric layer is 10 to 30 nm, the barrier layer is not completely oxidized even if the film thickness of the dielectric layer is changed, and in any case, the same level of solar radiation absorption is obtained. It turned out to show a rate. Therefore, it is presumed that even if the film thickness of the dielectric layer is further increased, it does not significantly affect the oxidation state of the barrier layer. This is considered to be because when the dielectric layer is formed on the barrier layer, the surface of the barrier layer is oxidized immediately after the start of film formation, so that there is no significant difference even if the film formation time is lengthened. Be done.

From the above, in each of the examples, the visible light transmittance was 50% or less, and the transmitted light had an intermediate color. Further, the reflectances of the glass surfaces were all less than 10%, and had good appearance quality with less glare. Furthermore, a ^* of the reflected light on the glass surface was in the range of -3 to -1.5, and the reddish and strong green tints were suppressed. Further, in b ^* , a noticeable tint was suppressed in the range of -10 to -6, and even if the reflected light on the glass surface was mixed with the intermediate color of the transmitted light, it showed a gray color tone as seen by the viewer. ..

On the other hand, in Comparative Examples 1 and 2 in which the solar absorptivity of the first barrier layer is about 21% and the solar absorptivity of the second barrier layer is smaller than the range of claim 1, the reflectance of the glass surface is 14%. %, which is out of the object of the present invention. Further, in Comparative Examples 3 and 4 in which the second barrier layer is within the scope of claim 1 and the solar radiation absorptivity of the first barrier layer exceeds 6%, the reflectance of the glass surface was slightly suppressed to about 10%. However, the reflectance was high as compared with the examples of the present invention. Further, from FIGS. 3 and 4, there was no comparative example in which both the transmitted color and the reflected color of the glass surface were in the same range as the example.

1: glass plate, 2: low emission film, 3: low emission glass plate, 11a: first dielectric layer, 11b: second dielectric layer, 11c: third dielectric layer, 12a: first Ag layer, 12b: second Ag layer, 13a: first barrier layer, 13b: second barrier layer, 14: uppermost layer, 21: spacer, 22, sealing material, 23: hollow layer

Claims (4)

In a low-emission glass in which a low-emission film having a gray color tone is formed on the surface of the glass plate, the low-emission film has a first dielectric layer, a first Ag layer, and a first barrier in order from the surface of the glass plate. A layer, a second dielectric layer, a second Ag layer, a second barrier layer, and a third dielectric layer,
The low emission film has an optical film thickness,
The first dielectric layer is 60 to 120 nm,
The second dielectric layer is 160-240 nm,
The third dielectric layer is 25-65 nm,
The physical thickness of the first Ag layer and the second Ag layer is 12 to 22 nm in total,
The film thickness of the second Ag layer≧the film thickness of the first Ag layer,
The first barrier layer has a solar radiation absorptivity of 0 to 6%, and the second barrier layer has a solar radiation absorptivity of 20 to 35%.
A gray tone low-emission glass, wherein the glass surface reflectance of the low-emission glass is less than 10%. In a low-emission glass in which a low-emission film having a gray color tone is formed on the surface of the glass plate, the low-emission film has a first dielectric layer, a first Ag layer, and a first barrier in order from the surface of the glass plate. A layer, a second dielectric layer, a second Ag layer, a second barrier layer, and a third dielectric layer,
The first barrier layer has a solar radiation absorptivity of 0 to 6%, and the second barrier layer has a solar radiation absorptivity of 20 to 35%.
The glass surface reflectance of the low-emission glass is less than 10%,
In the CIE L*a*b* chromaticity coordinate diagram, the reflection color of the glass surface of the low-emission glass when the thickness of the glass plate is 3 mm is a* of −5 to 0 and b* of −12 to −. Gray tone low-emission glass characterized by being 5. The gray according to claim 1 or 2, wherein the second barrier layer has at least one selected from the group consisting of Ti, NiCr, Nb, and stainless steel which is not oxidized or nitrided. Color low emissivity glass. A gray glass low-emission glass according to any one of claims 1 to 3 and a glass plate are integrated through a spacer to form a double-layer glass, and a low-emission film of the low-emission glass is formed. The double-sided glass is characterized in that the curved surface is on the spacer side.

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