JPH1149532A - Low reflection glass article and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low reflection glass article coated with an optical multilayer film capable of reducing reflectance over the wide range of the visible light region. SOLUTION: The 1st layer having a refractive index of 2.00-2.60, a dispersion coefft. ν of refractive index of 2-15 and 35-70 nm optical thickness, the 2nd layer having a refractive index of 1.35-1.55, a dispersion coefft. ν of refractive index of >=50 and 45-70 nm optical thickness, the 3rd layer having a refractive index of 2.00-2.60, a dispersion coefft. ν of refractive index of 2-15 and 45-135 nm optical thickness and the 4th layer having a refractive index of 1.35-1.55, a dispersion coefft. ν of refractive index of >=50 and 130-175 nm optical thickness are successively laminated on transparent glass substrate having a refractive index of 1.47-1.53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low-reflection glass article,
In particular, the present invention relates to a low-reflection glass article which covers the surface of a transparent glass substrate and has a function of preventing reflection of visible light, and a method for producing the same.

[0002]

2. Description of the Related Art Optical parts or consumer OA equipment, T
Many antireflection systems have been used so far to reduce the surface reflectance of V cathode ray tubes and display filters to enhance optical characteristics. These can be roughly classified into (1) a method using a surface uneven structure and (2) a method using an optical thin film system.

[0003] A method utilizing a surface uneven structure is based on a light scattering effect. This is a method in which an uneven structure having a size approximately equal to or smaller than the wavelength of light is provided on the surface of a substrate by a chemical or physical method, and the reflectance of the substrate is apparently reduced by scattering. For example, a method of etching a glass surface with hydrofluoric acid, a method of immersing glass in a supersaturated hydrofluoric acid solution to build a porous skeleton structure on the surface, a method of applying ultrafine particles such as silica to the surface, a spinodal decomposition And other methods utilizing micro phase separation.

[0004] The reduction of the reflectance by the optical thin film is due to the light interference effect. Theoretically optical film thickness n _f × d (n _f: refractive index, d: geometric thickness) of λ _0/4: formed on the thin film system is equal to (lambda ₀ the center wavelength of the design) is the substrate When the refractive index of the incident medium and the refractive index of the substrate are n ₀ and n _S , respectively, and the optical admittance of the thin film system is Y, the energy reflectance R is expressed by the following equation (1).

[0005]

R = ((n ₀ −Y) / (n ₀ + Y)) ²

Here, the non-reflection condition is Y = n ₀ . For ^{_{monolayer, Y = n 1 2 / n}} S next substrate is glass (n _S =
1.52), when the incident medium is air (n ₀ = 1) and a material having a refractive index n ₁ = 1.23 of the thin film is used,
It can be seen that the reflectance at λ ₀ becomes zero.

In the case of a two-layer structure, the composite optical admittance of a thin film system (second thin film + substrate) when one thin film (second counting from the incident medium side) is laminated on the substrate is represented by Ys.
Then, the first thin film system (the second thin film + substrate) is
The non-reflection condition when the layers are stacked is represented by the following formula 2, and the following formula 4 is obtained from the following formulas 2 and 3.

[0008]

## EQU2 ## Ys = n ₂ ² / n _S

[Number 3] ^{_{n 1 2 / Y s = n}} 0

## EQU4 ## n _S / n ₀ = n ₂ ² / n ₁ ²

That is, materials having a refractive index such that n ₂ / n ₁ = 1.23 may be combined. By selecting such two types of materials and adjusting the film thickness, an antireflection film having a reflectance of zero at a specific wavelength can be obtained.

[0010]

However, the above-mentioned method using the uneven surface structure utilizes scattering and does not essentially reduce the reflection. Therefore, there is a limit in reducing the reflectance, and the resolution is also reduced. In addition, for optical thin film systems that use optical interference to reduce reflectance,
In the case of a single layer film, a material that actually satisfies n ₁ = 1.23 and is practically durable is not known, and MgF ₂ (n _f = 1) having a refractive index close to this is not known. .38) is used. In this case, it is clear that the reflectance R of the coating surface can be reduced only to R = 1.26% by (Equation 1). In the case of a two-layer configuration, the reflectance at a specific wavelength can be made zero, but the wavelength range in which the reflectance can be reduced is narrow. For this reason, when the center wavelength is designed in the visible region, a V-shaped reflection curve in which the reflectance on the short wavelength side with high blue stimulus purity and the long wavelength side with high red stimulus purity is drawn is drawn. The reflection color was too strong to use. In addition, when the reflection color tone is improved by adjusting the refractive index, the non-reflection condition of (Equation 4) cannot be satisfied, so that the reflectance reduction effect cannot be sufficiently exhibited. It is known that, for an optical multilayer film having three or more layers, the wavelength region where the reflectance is close to zero can be increased, and at the same time, the reflection color can be improved. However, if the method of forming the thin film is a vacuum system, the equipment becomes large. Since the wet method is a multilayer film, there is a problem that the steps of coating and drying or baking are complicated and productivity is poor.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a low-reflection glass article coated with an optical multilayer film capable of reducing the reflectance in a wide range of visible light. I do.

[0012]

According to the present invention, the refractive index is 1.
On a transparent glass substrate of 47 to 1.53, 2.00 to 2.
A refractive index of 60, a refractive index dispersion coefficient ν of 2 to 15 and 35
A first layer having an optical thickness of ~ 70 nm;
A second layer having a refractive index of 1.55, a refractive index dispersion coefficient ν of 50 or more, and an optical thickness of 45 to 70 nm;
A third layer having a refractive index of 〜2.60, a refractive index dispersion coefficient ν of 2-15, and an optical thickness of 45-135 nm;
Refractive index of 35 to 1.55, refractive index dispersion coefficient ν of 50 or more
And a fourth layer having an optical film thickness of 130 to 175 nm, in which four layers are laminated in this order.

Hereinafter, the present invention will be described in detail. In the present invention, a first layer (high-refractive-index film), a second layer (low-refractive-index film), a third layer (high-refractive-index film) and a first layer (high-refractive-index film) are formed on a transparent glass substrate having a refractive index of 1.47 to 1.53. The fourth layer (low refractive index film) is laminated in that order. Here, the value of the refractive index is defined as a value for light having a wavelength of 550 nm unless otherwise specified. The range of the refractive index values of the first and third high refractive index films is 2.00 to 2.60, respectively, and the range of the high refractive index films of the second layer and the fourth layer is 1 respectively. .35 to 1.55.
To reduce the reflectance in the visible light region, the high refractive index film of the first layer is 35 to 70 nm, and the low refractive index film of the second layer is 45 nm.
To 70 nm, the high refractive index film of the third layer is 45 to 135 nm,
The low refractive index film of the fourth layer has an optical thickness of 130 to 175 nm.

The degree of the difference in the refractive index due to the difference in the wavelength of the light is defined by the refractive index dispersion coefficient ν as in the following equation (5).

[0015]

Ν = (n ₅₉₀ −1) / (n ₅₉₀ −n ₆₇₀ )

Here, n ₅₉₀ represents a refractive index at a wavelength of 590 nm, and n ₆₇₀ represents a refractive index at a wavelength of 590 nm.

The first layer, the second layer, the third layer and the fourth layer
The range of the refractive index dispersion coefficient ν of the layer is 2 to 12, 50, respectively.
Above, 2 to 12 and 50 or more. When the refractive index dispersion coefficient ν of each layer is out of the above range, small visible light reflection cannot be obtained. Table 1 summarizes the ranges of the refractive index, the optical film thickness, and the refractive index dispersion coefficient ν of the first to fourth layers. By selecting the refractive index, the optical film thickness and the refractive index dispersion coefficient ν in this manner, a low-reflection glass article having a visible light reflectance (film surface) of 0.5% or less, more preferably 0.3% or less, can be obtained. can get.

[0018]

================================ Refractive index Optical film thickness (nm) Refractive index dispersion coefficient ν --------------------- First layer 2.00 to 2.60 35 to 702 15 Second layer 1.35 to 1.55 45 to 70 50 or more Third layer 2.00 to 2.60 45 to 135 2 to 15 Fourth layer 1.35 to 1.55 130 to 175 50 or more === ==============================

The high-refractive-index films (first and third layers) according to the present invention are made of group IB (Cu, Ag, Au) of the periodic table,
Group IIA (Be, Mg, Ca, Sr, Ba, Ra),
Group IIB (Zn, Cd, Hg), Group IIIA (Sc, Y,
La, Ac), Group IIIB (B, Al, Ga, In, T)
l), Group IVA (Ti, Zr, Hf, Th), Group IVB (C, Si, Ge, Sn, Pb), Group VA (V, N
b, Ta, Pa), Group VB (N, P, As, Sb, B)
i), Group VIA (Cr, Mo, W, U), Group VIB (O, S, Se, Te, Po), Group VIIA (Mn, T)
c, Re, Np), Group VIII (Fe, Co, Ni, R)
u, Rh, Pd, Os, Ir, Pt, Pu, Am, C
It is preferable to contain at least 50 mol% of oxides of at least one element selected from m) in total. Among these, titanium (Ti), cerium (Ce), bismuth (B
i), an oxide of at least one metal selected from zirconium (Zr), niobium (Nb), and tantalum (Ta) is preferable.
O ₂ , CeO ₂ , Bi ₂ O ₃ , ZrO ₂ , Nb ₂ O ₅ , and Ta ₂ O ₅ , preferably 70 mol% in total
The content is more preferably 80 mol%, and still more preferably 90 mol%. Other components that may be included include silicon oxide and coloring components described below.

The low refractive index films (second and fourth layers) according to the present invention preferably contain silica in an amount of 70 mol% or more, more preferably 80 mol% or more, and are contained in the high refractive index film. Metal oxides, preferably from 0 to
The content is 30 mol%, more preferably 1 to 20 mol%. By including this metal oxide, the low-refractive-index film layer and the high-refractive-index film layer have close contraction coefficients in the curing process, and cracks and film peeling are unlikely to occur. Further, the adhesion at the interface between the low refractive index film layer and the high refractive index film layer can be improved. The high refractive index film includes a plurality of metal oxides, for example, titanium oxide and bismuth oxide.
When a species is contained, it is preferable that titanium oxide and bismuth oxide are contained in the low refractive index film at substantially the same ratio as that contained in the high refractive index film. Other components that may be included include the coloring components described below.

As specific embodiments of the optical thin films of the high refractive index films (first and third layers) and the low refractive index films (second and fourth layers) in the present invention, titanium oxide, oxide A film containing bismuth and silicon oxide can be exemplified. As described below, when the proportion of silicon oxide in each film is small, it is used as a high refractive index film, and when the proportion of silicon oxide in the thin film is large, it is used as a low refractive index film.

When an optical thin film containing titanium oxide, bismuth oxide and silicon oxide is used as a high refractive index film, the content of silicon oxide is preferably not more than 30 mol% in terms of SiO ₂ . A more preferred ratio is 2
0 mol% or less, more preferably 10 mol%
It is as follows.

The ratio of titanium oxide to bismuth oxide in the high refractive index film containing titanium oxide, bismuth oxide and silicon oxide of the present invention is preferably selected so as to maximize the refractive index of the film. Assuming that the oxidation states of titanium and bismuth are TiO ₂ and Bi ₂ O ₃ , respectively, the content of titanium oxide and bismuth oxide in the thin film is expressed as a molar ratio, and the content of Bi _{2 with} respect to the sum of TiO ₂ and Bi ₂ O ₃ The ratio of O ₃ , Bi ₂ O ₃ / (TiO ₂ + Bi ₂ O ₃ ), is preferably 1 to 96%, more preferably 2 to 60%, and still more preferably 3 to 50%. .

The titanium oxide in the high refractive index film, the content of bismuth oxide, and silicon oxide, as shown in FIG. _{1, TiO 2 -Bi 2 O 3} -SiO 2 ternary respectively in composition TiO _2, represents the molar ratio of Bi ₂ O _3, SiO ₂ in the coordinate point _{(TiO 2, Bi 2 O 3} , SiO 2 each mole%),
A (69, 1, 30), B (99, 1, 0), C (5,
95,0), square AB consisting of D (3,67,30)
It is necessary that the ratio be in the range of CD, and preferably, E (78,2,20), F (98,2,0), G
(40, 60, 0) and a ratio within the range of a square EFGH composed of H (32, 48, 20), more preferably I (87, 3, 10), J (97, 3, 0), K (5
0, 50, 0) and L (45, 45, 10) within the range of a square IJKL. When the content of titanium oxide, bismuth oxide, and silicon oxide in the high-refractive-index film is within the range of the square ABCD, a high-refractive-index film having a refractive index of 2.06 or more is obtained. Similarly, within the range of the square EFGH. A high-refractive-index film having a refractive index of 2.18 or more and a refractive index of 2.30 or more can be obtained in the range of the square IJKL. In the case where the optical thin film containing titanium oxide, bismuth oxide, and silicon oxide is used as a high refractive index film, components other than the above components, such as cerium oxide and zirconium oxide, must be used unless the refractive index is lowered so much. ,
Tantalum oxide, neobium oxide, tungsten oxide,
Antimony oxide or the like may be contained in a small amount, for example, 10% or less.

On the other hand, when an optical thin film containing titanium oxide, bismuth oxide and silicon oxide is used as the low refractive index film in the present invention, the content of silicon oxide is SiO 2
It is preferably at least 70 mol%, more preferably at least 80 mol%, and even more preferably at least 90 mol%, expressed as ₂ mol%.

As shown in FIG. 1, the contents of titanium oxide, bismuth oxide and silicon oxide in the low refractive index film are represented by M (0, 0,
100), N (29.5, 0.5, 70), O (1.5,
28.5, 70) must be within the range of a triangle MNO consisting of M (0, 0, 100), P
(19.5, 0.5, 80) and Q (8, 12, 80), preferably within the range of a triangle MPQ, more preferably M (0, 0, 100), R ( 9.
5,0.5,90) and S (5,5,90) within the range of the triangle MRS.

When the optical thin film containing titanium oxide, bismuth oxide and silicon oxide of the present invention is used as a low refractive index film (second and fourth layers), the ratio of titanium oxide to bismuth oxide in each film is as follows: It is preferable to approach the ratio of titanium oxide and bismuth oxide in the high refractive index films (the first layer and the third layer) to be laminated. By doing so, the difference in thermal shrinkage between the high-refractive-index film and the low-refractive-index film at the time of firing becomes small, and cracks and film peeling can be prevented. Further, the wavelength dispersion of the refractive index of the high-refractive-index film and the low-refractive-index film becomes close to each other, and the transmitted light color tone, the reflected light color tone, the visible light reflectance, etc. Optical properties are improved.

In the present invention, at least one of the high refractive index film and the low refractive index film may contain a coloring component. Examples of such a coloring component include metal ultrafine particles composed of one or more members selected from Group IB and Group VIII of the periodic table. Of these, preferred are noble metals such as Au, Pt, Pd, Rh, and Ag. These coloring component metal fine particles are preferably contained in an amount of 0.5 to 20 mol%.

The high refractive index film and the low refractive index film in the present invention can be formed by sputtering, CVD, or spray pyrolysis, but the sol-gel method is preferred from the viewpoint of cost. Is more desirable. For the coating by the sol-gel method, a spin coating method, a dip coating method, a flow coating method, a roll coating method, a gravure coating method, a flexographic printing method, a screen printing method and the like are used.

When an optical thin film containing titanium oxide, bismuth oxide and silicon oxide is formed by a sol-gel method on the high refractive index film and the low refractive index film in the present invention, the coating liquid composition is titanium It can be obtained by dissolving a hydrolyzable / condensable metal compound such as a compound, a bismuth compound, and a silicon compound in an organic solvent.

As the titanium compound, titanium alkoxide, titanium alkoxide chloride, titanium chelate and the like are used. As titanium alkoxide, titanium methoxide, titanium ethoxide, titanium n-propoxide,
Examples thereof include titanium n-butoxide, titanium isobutoxide, titanium methoxypropoxide, titanium stearyl oxide, and titanium 2-ethylhexoxide. Examples of the titanium alkoxide chloride include titanium chloride triisopropoxide, titanium dichloride diethoxide and the like. Titanium chelates include titanium triisopropoxaside (2,4-pentanedionate), titanium diisopropoxide (bis-2,4-pentanedionate), titanium allyl acetate triisopropoxide, Ethanolamine) diisopropoxide, titanium di-n-butoxide (bis-2,4-pentanedionate) and the like are used.

As the bismuth compound, bismuth nitrate, bismuth acetate, bismuth oxyacetate, bismuth acetate, bismuth chloride, bismuth alkoxide, bismuth hexafluoropentadionate, bismuth t-pentoxide, bismuth tetramethylheptanedionate and the like are used. . As the cerium compound, cerium nitrate, cerium chloride and the like are used. As the silicon compound, a compound obtained by mixing silicon alkoxide with a solvent such as alcohol, and promoting hydrolysis and polymerization with an acidic or basic catalyst is used. As the silicon alkoxide, silicon methoxide, silicon ethoxide, or an oligomer thereof is used. Examples of the acid catalyst include hydrochloric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, oxalic acid, trichloroacetic acid, trifluoroacetic acid, phosphoric acid, hydrofluoric acid, and formic acid. Ammonia and amines are used as the basic catalyst.

The organic solvent used in the coating liquid composition used to form the high refractive index film and the low refractive index film depends on the coating method, but includes methanol, ethanol, isopropanol, butanol, hexanol, octanol, Examples include methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, cellosolve acetate, diethylene glycol monoethyl ether, hexylene glycol, diethylene glycol, tripropylene glycol, diacetone alcohol and the like. As the coating liquid composition, the above-mentioned solvent may be used alone or plurally in order to adjust the viscosity, surface tension and the like of the coating liquid. Further, a small amount of a stabilizer, a leveling agent, a thickener, and the like may be added as needed.
The amount of the solvent used depends on the thickness of the high-refractive index film and low-refractive index film finally obtained, and the coating method to be used, but is usually used so that the total solid content falls within the range of 1 to 20%. Is done.

After the above-mentioned coating liquid composition is applied by the above-mentioned coating method, it is dried and / or baked by heating at a temperature of 250 ° C. or more, and then, further, a step of applying the next coating liquid thereon and drying or And / or repeating the steps of heating and firing, the ultraviolet ray reflective glass article is completed.
The film obtained in this way has excellent performance such as transparency, environmental resistance, and scratch resistance, and the process of densification of the high-refractive-index film layer and the low-refractive-index film layer even when the layers are laminated. In this case, it is possible to suppress film peeling and generation of cracks, which are likely to occur due to the difference in the thermal shrinkage in the above.

Instead of the above-described manufacturing method using drying and / or drying / firing by heating at 250 ° C. or higher, a light irradiation method described below can be used. That is, after applying the coating liquid composition by the application method,
This is a method in which a coating-drying step is repeated, in which a step of irradiating a coating film with an electromagnetic wave having a wavelength shorter than that of visible light is performed, and subsequently, a step of applying the next coating liquid is performed. Examples of electromagnetic waves having a wavelength shorter than that of visible light include γ-rays, X-rays, and ultraviolet rays. However, ultraviolet irradiation is preferable from the viewpoint of practicality of the apparatus in consideration of irradiation on a substrate having a large area. As an ultraviolet light source, an excimer lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, or the like is used. 36
Irradiate the coating film with an irradiation intensity of 10 mW / cm ² or more, preferably 50 mW / cm ² or more, more preferably 100 mW / cm ² or more, using a high-pressure mercury lamp that efficiently emits 254 nm and 303 nm with a main wavelength of 5 nm. It is desirable to do. Using such an ultraviolet light source, 1
MJ / cm ² or more, preferably 500 mJ / cm ² or more, more preferably to apply the 1000 mJ / cm ² or more radiation energy, the coating film surface coated with the coating composition of the present invention. Apply as many layers as necessary
After repeating the ultraviolet irradiation, if necessary, 500 to 80
Heat in oven heated to 0 ° C. for 10 seconds to 2 minutes. Thereby, a laminated film excellent in performance such as transparency, environmental resistance, and scratch resistance at a low temperature and hardly causing cracks is provided.

Drying and / or baking by heat may be simultaneously performed while irradiating ultraviolet rays. By simultaneously using a drying method by ultraviolet irradiation and a drying step by thermal drying at a temperature of preferably 250 ° C. or less, a coating film having excellent performance such as transparency, environmental resistance, and scratch resistance is given, and the lamination is performed. Even when the layers are stacked, it is possible to suppress film peeling and generation of cracks which are likely to occur due to a difference in heat shrinkage in the process of densification of the high refractive index film layer, the intermediate refractive index film layer, and the low refractive index film layer. By utilizing the ultraviolet irradiation as described above, the speed of the drying process can be increased, and the productivity can be dramatically improved.

As the glass substrate in the present invention, a transparent glass article having a refractive index of 1.47 to 1.53, for example, an uncolored glass plate having a transparent soda lime silicate glass composition, green color, bronze color, etc. A glass plate or the like having a performance of blocking ultraviolet rays or heat rays may be used, and a glass plate for automobiles having a thickness of 0.5 mm to 5.0 mm is preferably used, and one surface of the glass plate is used. Alternatively, the laminated film can be applied to both surfaces.

By selecting a specific range of the optical thicknesses of the high refractive index film, the intermediate refractive index film and the low refractive index film in the present invention, the reflectance at the set wavelength can be greatly reduced.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to examples. Preparation of high refractive index film forming solution composition (H solution): 24.9
g of bismuth nitrate pentahydrate (Bi raw material)
Of 2-ethoxyethanol, and 170.7 g of tetraisopropoxytitanium (Ti raw material) was added.
For 3 hours. After cooling to room temperature, a solution composition for forming a high refractive index film was obtained (H solution). In solution H, titanium and bismuth contained 9% in terms of TiO ₂ and Bi ₂ O ₃ respectively.
6 and 4 mol% were contained.

Preparation of low refractive index film forming solution composition (L solution): 150 g of ethyl silicate ("Ethyl silicate 40" manufactured by Colcoat) was mixed with 132 g of ethyl cellosolve, and 18 g of 0.1 mol / l hydrochloric acid was mixed. The mixture was stirred at room temperature for 2 hours (Liquid L1). When the amount of SiO ₂ is 9 in terms of oxides
The above solution H was mixed with the solution L1 so as to be 0 mol% to obtain a solution composition for forming a low refractive index film (solution L). In the L liquid, silicon, titanium, and bismuth are SiO ₂ , T
90, 9.8 and 0.2 in terms of iO ₂ and Bi ₂ O ₃
Each mol% was contained.

[Examples 1 to 12, Comparative Examples 1 to 8] Uncolored transparent soda-lime glass plate (thickness: 1.1 mm, visible light transmittance: 91.2%, visible light reflectance (surface on the incident light side) Only, 12 degree incidence): 4.03%, visible light reflectance (both surfaces; 12 degree incidence): 8.05%, Lab respectively.
Expressed by the chromaticity of the color system, the transmitted light chromaticity a = −0.39, b
= 0.2, transmitted light saturation ((a ² + b ² ) ^1/2 ) = 0.44, reflected light chromaticity a of only the surface on the incident light side a = 0.08, b = −
0.31, the reflected light saturation ((a ² + b ² ) ^1/2 ) = 0.32.
Reflected light chromaticity (both surfaces) a = 0.02, b = -0.4
0, the reflected light saturation ((a ² + b ² ) ^1/2 ) = 0.40) was washed with an alkaline aqueous solution for 20 minutes and then in ultrapure water for 20 minutes while irradiating with ultrasonic waves, and the substrate was washed. Obtained.

One surface of this substrate was coated with the above-mentioned H solution by a gravure coating method, and irradiated with ultraviolet light for 30 seconds at a radiation intensity of 15 mW / cm ² from a distance of 10 cm using a high-pressure mercury lamp of 160 W / cm. A one-layer film was formed. Subsequently, the L liquid is applied on the first layer film, and the same distance, irradiation intensity,
Ultraviolet irradiation was performed for an irradiation time to obtain a second layer. Subsequently, the H solution was applied on the second layer, and ultraviolet irradiation was performed using the high-pressure mercury lamp under the same conditions as above to form a third layer.
Subsequently, the L liquid was applied on the third layer, and ultraviolet irradiation was performed under the same conditions as above using the high-pressure mercury lamp to form a fourth layer. This was heated in an electric furnace heated to 720 ° C. for 30 seconds to obtain a low reflection glass plate in which a first layer, a second layer, a third layer, and a fourth layer were laminated on one surface of the substrate in that order.
The number of roll rotations in the gravure coating method of the first to fourth layers was changed to obtain various low reflection glass plates having different optical film thicknesses (Examples 1 to 12 and Comparative Examples 1 to 8). Table 2 shows the film composition of each layer.

Regarding the optical characteristics of the obtained low reflection glass plate, the visible light reflectance Rvis and the visible light transmittance Tvis conform to “JIS Z 8722”, and the reflectance is 12
It measured by the reflectance at the time of incidence. Here, the visible light reflectance of only the film surface (one surface) of the light incident from the film surface side and the visible light reflectance of both surfaces including the reflection of the back surface of the light incident from the film surface side are respectively R (S) vis And R (D) v
Notation is. The refractive index (n) was obtained by measuring the refractive index value for light having a wavelength of 550 nm by ellipsometry. Tables 3 and 4 show the refractive index (n), the refractive index dispersion coefficient (ν) defined by Expression 5, and the optical film thickness (nd), and the visible light reflectance R (S) vis only on the film surface; Expressed in the chromaticity of the Lab color system, the reflected light chromaticities a and b of the light projected from the film surface side only on the film surface (one surface) and the reflected light chromaticity ((a ² +
b ^{2) 1/2)} of each value of) shown in Tables 5 6. Then, the visible light reflectivity R (D) vis of both surfaces including the back surface and the reflected light chromaticity a of both surfaces including the reflection of the back surface with respect to the light projected from the film surface side,
b, and its respective value of the reflection Glow of ^{((a 2 + b 2)} 1/2)) shown in Table 7 Table 8, the visible light transmittance Tvis obtained while projecting light from each film surface Tables 9 and 10 show the values of the transmitted chromaticities a and b and the transmitted light saturation ((a ² + b ² ) ^1/2 ). When the same optical thin film is laminated and coated on both surfaces of the glass substrate, the value of the visible light reflectance of both surfaces including the back surface is
The visible light reflectance R (S) vis on the film surface of the low-reflection glass plate (coated only on one surface) irradiated with light from the film surface side was about twice. The visible light reflectance and reflected light chromaticity of only the film surface (one surface) are adjusted so that the back surface (non-film surface) of the glass plate is roughened, and a black paint is applied and cured to prevent light reflection on the back surface. Was measured.

FIG. 2 shows the spectral characteristics of the reflected light on the film surface when the light is incident on the low-reflection glass plate of Example 1 from the film surface side. In the figure, the reflectance of light at wavelengths of 450 nm, 550 nm and 580 nm is about 0.1 each.
%, About 0.15% and 0.01% or less.

As shown in Table 5 for Examples 1 to 12, the visible light reflectance R (S) vis on the film surface of the low-reflection glass plate of the present invention on which light was incident from the film surface side was 0.1. 12-0.48
%, Which is 0.5% or less, 4.03% of the visible light reflectance (only the surface on the incident light side) of the untreated glass substrate.
It can be seen that the effect of preventing visible light reflection is great. On the other hand, in Comparative Examples 1 to 8 in which the optical film thicknesses of the respective films were out of the range, as shown in Table 6, the visible light reflectance R (S) vis on the film surface side was 0.63 to 1.9.
Although it is 0%, which is smaller than the visible light reflectance of the untreated glass substrate (only the surface on the incident light side), the value is considerably larger than the value of the embodiment. Comparative Example 6
Although the visible light reflectance R (S) vis on the film surface side of this is a relatively small value of 0.63%, it is represented by the chromaticity of the Lab color system.
The saturation ((a ² + b ² ) ^1/2 ) of light reflected on the film surface when projected from the film surface side is as large as 62.24, which is larger than the value of 0.32 for the untreated glass substrate. However, the values in Examples 1 to 12 are 1.06 to 15.25, and the change in the saturation of the reflected light on the film surface side is not so large as in the comparative example.

Further, the visible light reflectance R (D) vis of both surfaces including the back surface is 4.12 to 4.47% in Examples 1 to 12 as shown in Table 7; It is smaller than 8.05% of the glass substrate. Example 1
The saturation of the reflected light on both surfaces including the back surface of ~ 12 is 0.47 ~
It is 5.0 or less in the range of 4.00, and the value of the untreated plate is 0.0.
The change from 40 is very small. Further, as shown in Table 9, the visible light transmittance Tvis of Examples 1 to 12 was 92.8 to 92.8.
93.2%, and the visible light transmittance Tvis 9 of the untreated plate
The value is higher than 1.2%.

[0047]

[Table 2] ============================ Film Composition of Each Layer (mol%) Layer Working Solution SiO ₂ TiO ₂ Bi ₂ O ₃ −−−−−−−−−−−−−−−−−−−−−−−−−−−−− First layer H liquid 0 964 4 Examples 1 to 12 Second layer L liquid 90 9. 8 0.2 Comparative Examples 1 to 8 Third layer H liquid 0 96 4 Fourth layer L liquid 90 9.8 0.2 ===================== =======

[0048]

[Table 3] =================================== First Layer Second Layer Third Layer Fourth Layer n ν nd n ν nd n ν nd n ν nd (nm) (nm) (nm) (nm) −−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−− Example 1 1 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 149 2 2.37 5.19 37 1.49> 100 52 2.37 5.19 90 1.49> 100 149 3 2.37 5.19 56 1.49> 100 52 2.37 5.19 90 1.49> 100 149 4 2.37 5.19 49 1.49> 100 52 2.37 5.19 66 1.49> 100 149 5 2.37 5.19 49 1.49> 100 46 2.37 5.19 90 1.49> 100 149 6 2.37 5.19 49 1.49> 100 61 2.37 5.19 66 1.49> 100 149 7 2.37 5.19 49 1.49> 100 52 2.37 5.19 97 1.49> 100 149 8 2.37 5.19 49 1.49> 100 52 2.37 5.19 78 1.49> 100 149 9 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 141 10 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 156 11 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 136 12 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 161 ===== =============================

[0049]

[Table 4] =================================== First Layer Second Layer Third Layer Fourth Layer n ν nd n ν nd n ν nd n ν nd (nm) (nm) (nm) (nm) −−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−− Comparative Example 1 2.37 5.19 26 1.49> 100 52 2.37 5.19 90 1.49> 100 149 2 2.37 5.19 73 1.49> 100 52 2.37 5.19 90 1.49> 100 149 3 2.37 5.19 49 1.49> 100 31 2.37 5.19 90 1.49> 100 149 4 2.37 5.19 49 1.49> 100 76 2.37 5.19 90 1.49> 100 149 5 2.37 5.19 49 1.49> 100 52 2.37 5.19 42 1.49> 100 149 6 2.37 5.19 49 1.49> 100 52 2.37 5.19 137 1.49> 100 149 7 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 126 8 2.37 5.19 49 1.49> 100 52 2.37 5.19 90 1.49> 100 179 ================== =================

[0050]

[Table 5]

[0051]

Table 6 ========================== Visible Light Reflected Light Chromaticity (Film Surface) Reflectance (Film Surface) ------ −−−−−−−−−− R (S) vis (%) a b (a ² + b ² ) ^1/2 −−−−−−−−−−−−−−−−−−−−−−−− −−−−− Comparative Example 1 1.39 10.60 -11.80 15.86 2 1.73 -5.32 -4.66 7.07 3 1.60 2.70 11.06 11.38 4 1.90 5.74 -18.08 18.97 5 1.07 3.97 -27.0 27.29 6 0.63 25.0 -57.0 62.24 7 1.08 5.92 -0.57 5.95 8 1.76 0.37 -10.95 10.96 =========================

[0052]

========================== Visible light Reflected light chromaticity (both sides) Reflectance (both sides) ------ −−−−−−−−−−−−− R (D) vis (%) a b (a ² + b ² ) ^1/2 −−−−−−−−−−−−−−−−−−− −−−−−−−−−− Example 1 1.14 0.57 -0.65 0.86 2 4.40 3.00 -2.65 4.00 3 4.32 -0.80 -0.47 0.93 4 4.45 -0.32 -2.53 2.55 5 4.27 0.47 -0.84 0.96 6 4.37 1.22 -2.68 2.94 7 4.12 1.48 -2.07 2.54 8 4.26 -0.31 -0.35 0.47 9 4.25 1.10 -0.11 1.11 10 4.24 0.21 1.68 1.69 11 4.47 1.61 -0.05 1.61 12 4.39 0.08 -2.46 2.46 =============== =============

[0053]

[Table 8] =========================== Visible light Reflected light chromaticity (both sides) Reflectivity (both sides) ------ −−−−−−−−−−−−− R (D) vis (%) a b (a ² + b ² ) ^1/2 −−−−−−−−−−−−−−−−−−− −−−−−−−−−−− Comparative Example 1 5.29 4.47 -5.80 7.32 2 5.62 -2.83 -2.66 3.88 3 5.49 1.30 -5.78 5.92 4 5.76 2.92 -9.76 10.19 5 5.01 1.65 -11.78 11.89 6 4.58 8.45 -20.10 21.80 7 5.03 2.46 -0.55 2.52 8 5.62 0.12 -5.92 5.92 ===========================

[0054]

[Table 9] ========================= Visible light Transmitted light chromaticity Transmittance------------------- −−− Tvis (%) a b (a ² + b ² ) ^1/2 −−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 93.2 − 0.59 0.18 0.62 2 93.0 -1.05 0.73 1.28 3 93.1 -0.35 0.11 0.37 4 92.9 -0.25 0.45 0.51 5 93.1 -0.50 0.16 0.52 6 93.0 -0.84 0.76 1.13 7 93.2 -0.82 0.55 0.99 8 93.1 -0.32 0.02 0.32 9 93.2 -0.67 0.03 0.67 10 93.1 -0.54 0.43 0.69 11 93.1 -0.77 0.00 0.77 12 92.8 -0.54 0.63 0.83 ==========================

[0055]

[Table 10]

[0056]

As described above in the detailed description of the invention,
According to the present invention, a low reflection glass article having a visible light reflectance of 0.5% or less can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing preferred compositions of a high refractive index film layer and a low refractive index film layer in the present invention.

FIG. 2 is a graph showing reflectance spectral characteristics of one example of the low reflection glass article of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02B 1/11 G02B 1/10 A

Claims (7)

[Claims] 1. A transparent glass substrate having a refractive index of 1.47 to 1.53, a refractive index of 2.00 to 2.60, a refractive index dispersion coefficient ν of 2 to 15, and an optical film thickness of 35 to 70 nm. A second layer having a refractive index of 1.35 to 1.55, a refractive index dispersion coefficient ν of 50 or more, and an optical thickness of 45 to 70 nm, and a refractive index of 2.00 to 2.60. Rate, 2-1
A third layer having a refractive index dispersion coefficient ν of 5 and an optical film thickness of 45 to 135 nm, a refractive index of 1.35 to 1.55,
A low-reflection glass article comprising: a fourth layer having a refractive index dispersion coefficient ν of 0 or more and an optical film thickness of 130 to 175 nm, in which four fourth layers are laminated in this order. 2. The method according to claim 1, wherein each of said first and third layers contains at least 70 mol% of a metal oxide selected from the group consisting of titanium, cerium, bismuth, zirconium, niobium and tantalum. The second layer and the fourth layer each contain 70 mol% or more of silica, and a total of 0 to 3 oxides contained in the high refractive index film.
The low reflection glass article according to claim 1, which contains 0 mol%. 3. The method according to claim 1, wherein each of the first layer and the third layer is
Titanium oxide, bismuth oxide, and silicon oxide were used to determine the molar ratio of TiO ₂ , Bi ₂ O ₃ , and SiO _{2 in} a TiO ₂ —Bi ₂ O ₃ —SiO ₂ ternary composition by using coordinate points (TiO ₂ , Bi ₂ O ₃ , SiO ₂ mol%)
A (69, 1, 30), B (99, 1, 0), C (5,
95,0), square AB consisting of D (3,67,30)
The second layer and the third layer each contain titanium oxide, bismuth oxide, and silicon oxide at a ratio within the range of CD, and are represented by M
(0,0,100), N (29.5,0.5,70),
The low-reflection glass article according to claim 1 or 2, which contains O (1.5, 28.5, 70) in a ratio within a range of a triangle MNO. 4. The transparent glass substrate has a thickness of 0.5 to 5.0 m.
The low reflection glass article according to any one of claims 1 to 3, which is a glass plate having a thickness of m. 5. A method according to claim 1, wherein at least one of said first to fourth layers is made of at least one metal selected from the group consisting of groups IB and VIII of the periodic table.
The low-reflection glass article according to any one of claims 1 to 4, wherein the low-reflection glass article contains from 20 to 20 mol%. 6. A step of applying a liquid composition for forming an antireflection film formed by dissolving a hydrolyzable / condensable metal compound in an organic solvent to the surface of a transparent glass substrate, and thereafter irradiating the coated surface with ultraviolet rays. 2. The method for producing a low-reflection glass article according to claim 1, comprising a step of repeating the coating step and the ultraviolet irradiation step three times on the surface of the substrate on which the coating is performed. 7. The metal compound is selected from titanium alkoxide, titanium halide or a compound selected from these chelates as a titanium raw material, and bismuth nitrate, bismuth oxyacetate, bismuth chloride, bismuth alkoxide as a bismuth raw material. Compound, cerium nitrate as a cerium raw material, a compound selected from cerium chloride, silicon alkoxide as a silica raw material,
The method for producing a low-reflection glass article according to claim 6, which is at least one kind of a compound selected from an oligomer thereof and a hydrolysis-condensation product thereof.