JPH10236847A - Optical thin film, its forming composition and ultraviolet-absorbing and heat ray-reflecting glass using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical thin film having a high refractive index to enhance the selectivity in heat ray reflection and capable of absorbing UV and a UV-absorbing and heat ray-reflecting glass using the thin film. SOLUTION: This optical thin film contains titanium oxide, cerium oxide and bismuth oxide. In this case, the contents of the titanium oxide, cerium oxide and bismuth oxide are expressed by the coordinates (TiO2 mol%, CeO mol% and Bi2 O3 mol%) lie within the tetragon consisting of A(4, 1, 95), B(98, 1, 1), C(20, 79, 1) and D(3, 14, 83). Meanwhile, this UV-absorbing and heat ray- reflecting glass is formed by laminating a high-refractive-index film layer and a low-refractive-index film layer alternately on a transparent glass substrate at least in three layers, and at least one layer among the high-refractive-index films is an optical thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an optical thin film, particularly a high refractive index film suitable for providing a function of absorbing ultraviolet rays and reflecting heat rays by coating the surface of a transparent glass substrate, and the high refractive index film. And a UV-absorbing heat ray reflective glass using the high refractive index film.

[0002]

2. Description of the Related Art In recent years, ultraviolet rays and heat rays of sunlight entering a vehicle or a room are shielded to prevent deterioration of interior components.
There is an increasing demand for an ultraviolet heat ray shielding glass for preventing sunburn, reducing the feeling of heat and heat, and reducing the load on cooling equipment. In order to achieve this purpose, a high-refractive-index layer having a high-refractive-index layer and a low-refractive-index layer having an ultraviolet-absorbing ability are alternately laminated on the glass surface, or a heat-reflective glass that transmits visible light and selectively reflects heat rays. Various types of UV absorbing heat ray reflective glass have been developed.

[0003] In order to use this ultraviolet ray absorbing heat ray reflective glass as an automotive windshield in which the lower limit of the visible light ray transmittance is set to 70%, the reflectivity of only the heat ray region without reducing the visible ray transmittance. It is necessary to increase. For this purpose, for the high refractive index layer and the low refractive index layer, a method of increasing the number of interfaces (the number of layers) of these interfaces and a method of increasing the difference between the refractive index of the high refractive index layer and the refractive index of the low refractive index layer are used. There is.

For example, JP-A-6-345488 discloses that
A heat reflecting glass coated with a heat reflecting film having a two-layer structure of a high refractive index layer and a low refractive index layer is described. The low-refractive-index layer described here has an intermediate refractive index between the glass substrate and the high-refractive-index layer. This heat ray reflective glass has insufficient heat ray reflection performance because the number of layers is two and the low refractive index layer has an intermediate refractive index.

Japanese Patent Application Laid-Open No. 4-177204 discloses an ultraviolet and infrared cut filter, and Japanese Patent Application Laid-Open No. 8-104544 discloses a heat-reflection ultraviolet absorbing glass and a method for producing the same. As a high refractive index film used for the heat ray reflective glass disclosed in these publications, literature (Akio Makishima, et al.,
J. Am. Ceram. Soc., 69 [6] C-127-C-129 (1986)], a cerium oxide or an ultraviolet absorbing film containing cerium oxide and titanium oxide as main components. Used. The composition ratio of the film composed of cerium oxide and titanium oxide is selected so as to exhibit its ultraviolet absorbing ability.

JP-A-8-239244 discloses a three-layer structure of a high refractive index layer, a low refractive index layer, and a high refractive index layer.
An ultraviolet absorbing glass in which each layer has an optical thickness of 170 to 400 nm is described, wherein one of two high refractive index layers made of titanium oxide is composed of cerium oxide, preferably cerium oxide with respect to titanium oxide. Weight ratio is 0.1
It is disclosed to be contained so as to be ~ 5.0.

[0007] Japanese Patent Application Laid-Open No. 7-281023 describes a high refractive index film containing titanium oxide and bismuth oxide, and an incandescent lamp with an infrared reflecting film using the same.

[0008]

However, the above-mentioned ultraviolet / infrared cut filter (Japanese Patent Laid-Open No. 4-177204),
Heat-reflecting ultraviolet absorbing glass (Japanese Patent Laid-Open No. 8-104544)
No.) and an ultraviolet absorbing glass (JP-A-8-23924).
No. 4), the heat ray reflection performance was not maximized. In addition, the high refractive index film used in the incandescent lamp with the infrared reflective film (Japanese Patent Application Laid-Open No. 7-281023) did not exhibit sufficient ultraviolet absorbing ability.

The present invention has been made in order to solve such problems, and has an optical thin film having a high refractive index for improving heat ray reflection selecting performance and an ultraviolet absorbing performance, and using the same. It is an object of the present invention to provide an ultraviolet ray absorbing heat ray reflective glass.

[0010]

The present invention is an optical thin film containing titanium oxide, cerium oxide and bismuth oxide.

Hereinafter, the present invention will be described in detail. The optical thin film having a high refractive index in the present invention contains titanium oxide, cerium oxide and bismuth oxide. Titanium oxide helps to increase the refractive index of the thin film and gives the thin film ultraviolet absorption performance, and cerium oxide helps to give the thin film ultraviolet absorption performance. If the ratio of cerium oxide in the thin film is too small, the effect of ultraviolet absorption is not seen. Conversely, if the proportion of cerium oxide is too large, the refractive index will decrease. Thus the ratio of the content of titanium oxide and cerium oxide in the thin film, expressed in these molar ratios assuming respective oxidation states and TiO _2, CeO _2, the ratio of CeO ₂ to the total of TiO ₂ and CeO ₂ , CeO ₂ / (TiO ₂ + CeO ₂ ) needs to be 0.99 to 80%, a more preferable ratio is 20 to 60%, and a further preferable ratio is 3
0 to 50%.

The refractive index can be improved by allowing bismuth oxide to coexist in the thin film containing titanium oxide and cerium oxide. Even if the proportion of bismuth oxide in the thin film is very small, there is an effect of improving the refractive index, but if too much is added, the proportions of titanium oxide and cerium oxide relatively decrease, so that the effect of ultraviolet absorption decreases. Thus the ratio of the content of titanium oxide and bismuth oxide in the thin film, assuming the oxidation state of bismuth Bi ₂ O _3, respectively, in mole ratio of TiO ₂ and Bi ₂ O _3, TiO ₂ and Bi ₂ O the ratio of Bi ₂ O ₃ to the total of _3,
Bi ₂ O ₃ / (TiO ₂ + Bi ₂ O ₃ ) needs to be 1 to 96%, a more preferable ratio is 4 to 60%, and a still more preferable ratio is 4 to 50%.

Therefore, the content of titanium oxide, cerium oxide and bismuth oxide in the optical thin film having a high refractive index and ultraviolet absorption of the present invention is TiO ₂ -CeO ₂ -Bi ₂
In the O ₃ -based ternary composition, as shown in the graph of FIG.
The molar ratios of TiO ₂ , CeO ₂ , and Bi ₂ O ₃ are respectively represented by coordinate points (TiO ₂ mol%, CeO ₂ mol%, Bi ₂ O ₃ mol%), and A (4,1,95), B ( 98,1,1), C (20,79,
1) and D (3,14,83) must be within the range of a square ABCD, more preferably E (3,14,83).
6,9,55), F (77,20,3), G (39,59,2), H (24,38,
38), and more preferably a ratio within the range of a square EFGH consisting of I (54,23,23), J (68,29,3), K (4
9,48.5,2) and L (39,39,22) within the range of a square IJKL. The range of the square IJKL is most preferable because the refractive index of the thin film is increased, the thin film is provided with ultraviolet absorbing performance, and the thin film is less likely to be clouded.

The refractive index of a thin film of titanium oxide and cerium oxide having ultraviolet absorption performance also depends on the heating temperature for forming the thin film. In the case of a thin film obtained under the same sintering conditions, the thin film contains bismuth oxide. It can be improved in the range of 0.01 to 1.00.

[0015] The thin film obtained under the same firing conditions is made of TiO ₂
An optical thin film composed of 60 mol% and 40 mol% of CeO ₂ and having an ultraviolet absorbing performance has, for example, a refractive index of 1.99 with respect to light having a wavelength of 550 nm. An optical thin film having performance and a high refractive index (wavelength: 550 nm) of 2.00 to 2.35 can be obtained. And the optical thin film of the present invention usually has a geometric thickness of 50 to 500 nm.

Although the optical thin film of the present invention contains titanium oxide, cerium oxide and bismuth oxide, components other than the above components, such as Zr oxide, Ta oxide, Nb oxide,
A small amount of W oxide, Sb oxide, Si oxide, etc., for example, may be contained in a total of 10 mol% or less.

In a heat ray reflective glass comprising at least three layers of high refractive index films and low refractive index films alternately laminated on a transparent glass substrate, at least one of the high refractive index films
By making the layer an optical thin film having the above-mentioned ultraviolet absorbing performance and high refractive index, an ultraviolet absorbing heat ray reflective glass can be obtained. It is preferable that at least two of the at least three layers are high refractive index films. Further, it is more preferable that all the high refractive index films are optical thin films having the above-mentioned ultraviolet absorbing performance and high refractive index, since the ultraviolet absorbing performance and the heat ray reflecting performance can be enhanced.

As for the number of layers of the high refractive index film and the low refractive index film, it is desirable that the larger the number, the higher the reflectance at the set wavelength can be. However, when the number of layers is increased, cracks and pinholes are generated by baking, and the number of layers is preferably 7 or less, from the viewpoint that the film strength is reduced, or the number of coatings is increased and the cost is undesirable. More preferably, 5 layers or less, and most preferably, 3 layers.

Regarding the order of laminating the high refractive index film and the low refractive index film, the high refractive index film may be formed first on the transparent substrate and then the low refractive index film may be formed, or vice versa. They may be stacked. However, from the viewpoint of increasing the reflectance at the center wavelength of the heat ray (infrared ray) to be set, it is preferable that the number of layers is an odd number and the uppermost layer or the lowermost layer is a layer of a high refractive index film. In this case, when the number of layers is three, at least two high-refractive-index films are required, so that the high-refractive-index film must be first formed on a transparent substrate. When the number of layers is even, the optical film thickness of the lowermost or uppermost low-refractive-index film may be set to ８ of the set wavelength to improve color stability.

The high refractive index film has a thickness of 680 nm to 200 nm.
1/4 wavelength of light (heat ray) having a wavelength of 0 nm, that is, 17
It preferably has an optical thickness of 0 to 500 nm,
More preferably, it has an optical film thickness of ４ wavelength of light having a wavelength of from 00 nm to 1200 nm, that is, 175 to 300 nm, so that the visible light transmittance is not significantly reduced from the value of the transparent substrate itself. Can be increased. Further, the low refractive index film may have a refractive index smaller than that of the high refractive index film, but in order to enhance the heat ray reflection performance when alternately laminated with the high refractive index film of the present invention, It is desirable that the refractive index is equal to or lower than the refractive index of the transparent substrate. Float glass used as a transparent substrate usually has a refractive index of about 1.5. As the low refractive index film, for example, a substance having a refractive index of 1.5 or less, for example, a refractive index of 1.46 (wavelength 460 to 850 nm)
Of silica alone and a film containing silica as a main component are conveniently used, and an optical film having a wavelength of 1/4 wavelength of heat rays, that is, 170 to 500 nm, like the optical film thickness of the high refractive index film. Preferably from 700 nm to 12
１ ／ wavelength of light having a wavelength of 00 nm, that is, 175 to 3
More preferably, it has an optical thickness of 00 nm.

As described above, a high-refractive-index film having a very high refractive index is used, and the optical film thickness of the high-refractive-index film and the optical film thickness of the low-refractive-index film are set to the value of １ ／ wavelength of the heat ray. By doing so, the reflectance in the heat ray region can be selectively increased, and the visible light transmittance can be maintained at a value close to the value of the transparent substrate itself.

The high refractive index film and the low refractive index film of the present invention can be formed by a sputtering method or a CVD method, but it is more preferable to use the sol-gel method from the viewpoint of cost. 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.

The coating liquid composition by the sol-gel method used for forming the high refractive index film of the present invention comprises a titanium compound, a cerium compound, a bismuth compound and a solvent, and the titanium compound, the cerium compound and the bismuth compound are converted to an organic solvent. Obtained by mixing. As the titanium compound, titanium alkoxide, titanium alkoxide chloride, titanium chelate and the like are used. Examples of the titanium alkoxide include titanium methoxide, titanium ethoxide, titanium n-propoxide, 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.

Examples of the titanium chelate include titanium triisopropoxaside (2,4-pentanedionate), titanium diisopropoxide (bis-2,4-pentanedionate), titanium allyl acetate triisopropoxide,
Titanium bis (triethanolamine) diisopropoxide, titanium di-n-butoxide (bis-2,4-pentanedionate) and the like are used. As the cerium compound, cerium nitrate hexahydrate, cerium chloride, cerium isopropoxide, cerium t-butoxide, cerium methoxy ethoxide and the like are used. Bismuth compounds include bismuth nitrate, bismuth acetate, bismuth oxyacetate, bismuth chloride, bismuth hexafluoropentadionate,
Bismuth t-pentoxide, bismuth tetramethylheptanedionate and the like are used.

In the coating liquid composition, a titanium compound, a cerium compound, and a bismuth compound are converted into TiO ₂ , CeO ₂ , and Bi ₂ O ₃ , respectively.
Coordinate points of the molar ratio of these oxides (TiO ₂ mol%,
Expressed as CeO ₂ mol%, Bi ₂ O ₃ mol%, A (4,
1,95), B (98,1,1), C (20,79,1), D (3,14,83)
Within the range of a square ABCD consisting of
(36,9,55), F (77,20,3), G (39,59,2), H (24,
38, 38), more preferably I (54, 23, 23), J (68, 29, 3), K (49, 48.
5,2) and L (39,39,22) in a ratio within the range of a square IJKL. The range of the square IJKL is most preferable because the coating liquid composition has a long life and can be stored for a long period of time, in addition to having excellent characteristics of the film.

The sol-gel coating solution composition used for forming the low refractive index film of the present invention comprises a silicon compound and a solvent. As this composition, a composition 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, acetic acid, oxalic acid, trichloroacetic acid, trifluoroacetic acid, phosphoric acid, hydrofluoric acid, and formic acid. As the basic catalyst, ammonia and amines are used. Oxide of a metal other than silicon to silica, for example, titanium oxide, cerium oxide, bismuth oxide, aluminum oxide, zirconium oxide, etc., as long as the refractive index is not significantly increased, the mechanical strength of the film is improved, the environmental resistance is improved, Alternatively, they may be mixed to adjust the refractive index. Alternatively, ultrafine silica particles or silica particles containing fluorine or having a further reduced refractive index by being porous may be used.

The organic solvent used in the coating liquid composition used for forming 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. In the coating liquid composition of the present invention, the above-mentioned solvent may be used alone or a plurality of the solvents may be used to adjust the viscosity, surface tension and the like of the coating liquid. Also, a stabilizer,
A small amount of a leveling agent, a thickener, or 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 also on the coating method to be employed, but usually the total solid content is within the range of 1 to 20%. used.

The above-mentioned coating liquid composition is applied to a glass substrate by using the above-mentioned various application methods, and then applied at a temperature of 100 to 300 ° C. in an oxidizing atmosphere (in air).
After drying for up to 120 minutes,
By baking for 100 minutes, a high refractive index film or a low refractive index film is formed. Drying and baking operations may be performed for each of the high-refractive-index film and the low-refractive-index film to be laminated, but after applying and drying the high-refractive-index film and the low-refractive-index film, respectively, the baking is performed at once. May be performed.
Further, instead of the above-mentioned heat drying at 100 to 300 ° C., light irradiation drying may be performed for 10 seconds to 10 minutes with ultraviolet rays, visible light, or the like, or both may be used in combination.

The reason why the optical thin film of the present invention has an ultraviolet absorbing performance is presumed to be due to the Ti—O—Ce bond. The reason why the refractive index is improved when Bi is present is that titanium and bismuth in the thin film are composed of a composite oxide of titanium and bismuth, Ti _x Bi _y O _z , for example, a bismuth itanate-like compound, titanium oxide Ti
_x O _z and bismuth oxide Bi _y O _z are considered to exist alone or in a mixed state, or in a mixed state with crystalline or amorphous, and any of these contributes to the improvement of the refractive index. It is estimated to be.

By combining the high refractive index film of the present invention with a low refractive index film and laminating it on a normal non-colored glass substrate, an ultraviolet-absorbing non-colored glass substrate or an ultraviolet-absorbing colored glass substrate, the visible light transmission of the substrate glass is achieved. The visible light transmittance (Ya) of 70% or more, 60% or less and 1% less than the visible light transmittance without significantly lowering the transmittance and significantly changing the transmission color tone and the reflection color tone of the substrate glass.
Sunlight transmittance (Tg) of 5% or less and ultraviolet transmittance of 25% or less (according to ISO 9050; hereinafter, TUV (I
SO)) is obtained. Particularly, as a substrate glass, an ultraviolet transmittance Tuv (IS
By using a colored glass plate having a thickness of 2.0 to 5.0 mm having a value of O) of 10% or less, a UV absorbing heat ray reflective glass suitable for a vehicle window can be obtained.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to examples. [Examples 1 to 12 and Comparative Examples 1 and 2] Preparation of solution composition for forming high refractive index film: 24.9 g of bismuth nitrate pentahydrate (Bi raw material) was mixed with 118.6 g of 2-ethoxyethanol. Then, 170.7 g of tetraisopropoxy titanium (Ti raw material) was added, and the mixture was stirred at 60 ° C. for 3 hours. After cooling to room temperature, a solution prepared by dissolving 173.4 g of cerium nitrate hexahydrate (Ce raw material) in 120 g of 2-ethoxyethanol was added, and the mixture was stirred at room temperature for 1 hour to obtain a solution A of A1 in Table 1. A corresponding solution composition for forming a high refractive index film was obtained. By adjusting the amounts of addition of the three types of Bi raw material, Ti raw material, and Ce raw material in the same manner, they were mixed so as to have the composition ratio (molar ratio) shown in Table 1, and the 13 types of A2 to A14 Ti were mixed.
The O ₂ -CeO ₂ -Bi ₂ O ₃ containing composition was prepared. (A
liquid)

A soda-lime glass plate (thickness:
3.5 mm, visible light transmittance: 90%, sunlight transmittance: 84.7%, ultraviolet transmittance (wavelength 370 nm): 7
6.2%, refractive index: about 1.54 and 1.50 for light having wavelengths of 460 nm and 850 nm, respectively), and then applying the composition A solution by spin coating.
After drying at 50 ° C. for 1.5 hours, it was heated in an electric furnace heated to 720 ° C. for 2 minutes and fired. Each of the obtained films has a thickness of about 100 nm and its refractive index (measurement wavelength 370).
nm, 550 nm and 900 nm) and the extinction coefficient of the film itself (measuring wavelength 370 nm) are shown in Table 1. The refractive index was measured by ellipsometry. The results of observing the appearance of the film with the naked eye are shown in Table 1, and those having no abnormality in the film are described as “good”, and those having cracks in the film are described as “crack”. From the table, if the bismuth oxide content is 2.5% or more in terms of Bi ₂ O ₃ , the film has a high refractive index, that is, the refractive index at the measurement wavelength of 370 nm is 2.20 or more, and the refractive index at the measurement wavelength of 550 nm is 2.00 or more, the refractive index at a measurement wavelength of 900 nm is 1.96 or more, and 370
It is apparent that a film having an extinction coefficient of 0.15 nm or more is formed.

On the other hand, when bismuth oxide does not exist, the extinction coefficient at 370 nm is almost the same as that when bismuth oxide exists, but the refractive index is slightly small, and the film cracks and the film strength decreases. (Comparative Example 1). In addition, it is clear that when cerium oxide is not present, the ultraviolet absorbing ability is extremely small (Comparative Example 2). In addition, optical characteristics are shown by visible light transmittance (Ya: JIS Z872).
2), sunlight transmittance (Tg: JIS Z 872)
2), visible light reflectance (Ra: reflectance at an incidence of 12 degrees J
IS R 3106). The compositions of the optical films of the examples and the comparative examples are shown in TiO ₂ —CeO ₂ of FIG.
-Bi are plotted in ₂ O ₃ ternary composition chart.

[0034]

Table 1 =================================== No. Oxide Equivalent Molar Ratio Refractive Index n extinction film mol% ----------- coefficient k appearance A solution _{(TiO 2, CeO 2, Bi} 2 O 3) (370nm) (550nm) (900nm) (370nm) ----- −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 A1 (58.5, 39, 2.5) 2.26 2.03 1.96 0.19 Good 2 A2 ( 57, 38, 5) 2.34 2.11 2.03 0.22 Good 3 A3 (54, 36, 10) 2.36 2.13 2.05 0.19 Good 4 A4 (48, 32, 20) 2.51 2.27 2.19 0.18 Good 5 A5 (42, 28, 30) 2.52 2.28 2.20 0.17 Good 6 A6 (54, 24, 22) 2.57 2.30 2.21 0.17 Good 7 A7 (67, 30, 3) 2.60 2.35 2.26 0.17 Good 8 A8 (49, 48, 3) 2.24 2.02 1.96 0.17 Good 9 A9 (40, 39, 21) 2.38 2.13 2.05 0.17 Good 10 A10 (20, 20, 60) 2.28 2.05 1.98 0.20 Good 11 A11 (70, 10, 20) 2.60 2.31 2.21 0.15 Good 12 A12 (25 , 60, 15) 2.20 2.00 1.97 0.19 Good −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 A13 ( 60, 40, 0) 2.19 1.99 1.95 0.19 Crack 2 A14 (95, 0, 5) 2.68 2.37 2.28 0.018 good ========================= ===========

Examples 13 to 17, Comparative Examples 3 and 4 Preparation of low refractive index film forming solution composition (Solution B): Ethyl silicate ("Ethyl silicate 40" manufactured by Colcoat Co., Ltd.)
150 g was mixed with 132 g of ethyl cellosolve.
18 g of mol / l hydrochloric acid was added and the mixture was stirred at room temperature for 2 hours (B
liquid).

Example 13 Uncolored soda-lime glass plate (thickness: 3.5 mm, visible light transmittance: 89.3)
%, Sunlight transmittance: 72.6%, ultraviolet transmittance (37
0 nm): 57.7%, UV transmittance (Tuv (IS
O)): 53.4%) was washed by the method described in Example 1, and then the solution A4 of A4 was formed on one surface of the glass plate by spin coating, followed by 1.5 hours at 250 ° C. After drying, a first layer film was formed. Subsequently, the solution B was applied on the first layer film, and dried at 250 ° C. for 1.5 hours.
The resultant was heated in an electric furnace heated for 60 minutes and fired to form a second layer made of silica. Subsequently, on the second layer, the A4
The same liquid A was applied and dried by the method described in Example 1.
Firing was performed to form a third layer. The thickness of each layer was determined by a simulation calculation so that the transmittance of sunlight was minimized within a range in which the transmission color tone and the reflection color tone of the glass plate with the film were almost close to the color tone of the substrate. The thickness of each layer was determined in the same manner in Examples 14 to 16 and Comparative Examples 3 and 4.

The obtained heat ray reflective glass has a first layer of 98n.
m, the second layer has a geometric thickness of 151 nm, the third layer has a geometric thickness of 90 nm, visible light transmittance of 79.4%, sunlight transmittance of 58.6%, transmittance of 370 nm of 21.0%,
Tuv (ISO) was 19.4%. As for the color tone, the transmission color and the reflection color of the glass surface were the same as the color tone of the substrate. The optical thicknesses of the first layer, the second layer and the third layer have a refractive index (2.1 for light having a wavelength of 900 nm).
9, 1.46 and 2.19) were 214.6 nm, 220.5 nm and 197.1 nm, respectively.

Example 14 A green soda lime glass plate (thickness: 3.5 mm, visible light transmittance: 81.0%, sunlight transmittance: 60.8%, ultraviolet transmittance (370 nm)) was used as the substrate glass. : 52.6% and UV transmittance (Tuv (ISO): 31.4%) were used in the same manner as in Example 13. In the obtained heat ray reflective glass, the first layer was 109 nm, the second layer was 142 nm, and the third layer was 9 nm.
It has a geometric thickness of 1.5 nm and a visible light transmittance of 7
2.1%, sunlight transmittance 43.8%, transmittance at 370 nm 14.6%, Tuv (ISO) was 8.7%. As for the color tone, the transmission color and the reflection color of the glass surface were the same as the color tone of the substrate.

Example 15 A bronze-colored soda lime glass plate (thickness: 3.5 mm, visible light transmittance: 79.3%, solar light transmittance: 72.68%) was used as the substrate glass.
The procedure was performed in the same manner as in Example 13 except that the ultraviolet transmittance (370 nm): 57.7% and the ultraviolet transmittance (Tuv (ISO)): 38.2%. In the obtained heat ray reflective glass, the first layer has a thickness of 98 nm, the second layer has a thickness of 148 nm, and the third layer has a thickness of 95 nm.
with a geometric thickness of 7 nm and a visible light transmission of 72.2
%, Sunlight transmittance 52.1%, transmittance at 370 nm 16.6%, and Tuv (ISO) was 9.8%. As for the color tone, the transmission color and the reflection color of the glass surface were the same as the color tone of the substrate.

Example 16 As a substrate glass, green glass having an ultraviolet absorbing ability (thickness: 3.5 mm, visible light transmittance: 72.8%, sunlight transmittance: 48.8)
%, Ultraviolet transmittance (370 nm): 26.9%, and ultraviolet transmittance (Tuv (ISO)): 9.5%). The transmittance of the obtained glass with a film at 370 nm is 6.8%, Tuv (ISO) is 3.4%, visible light transmittance is 72.2%, and sunlight transmittance is 37.6%. The color tone in transmission and reflection was the same as that of the substrate.

Example 17 Bronze glass having an ultraviolet absorbing ability (thickness: 3.5 mm, visible light transmittance: 73.9%, sunlight transmittance: 65.3) as a substrate glass
%, Ultraviolet transmittance (370 nm): 29.7%, and ultraviolet transmittance (Tuv (ISO)): 9.6%. The transmittance of the obtained glass with a film at 370 nm is 7.4%, Tuv (ISO) is 3.7%, visible light transmittance is 72.0%, and sunlight transmittance is 49.4%. The color tone in transmission and reflection was the same as that of the substrate.

As can be seen from Examples 13 to 17, by providing a coating film consisting of three layers on various glass substrates, it is possible to maintain the visible light transmittance at a high value, especially 70% or more, and to maintain the visible light transmittance at a high value. Absorptive heat ray reflective glass, especially UV ray transmittance (Tuv (ISO)) when the sunlight ray transmittance is 60% or less and the value of (visible light ray transmittance-sunlight ray transmittance) is 15% or more.
Is 25% or less. Further, the values of the visible light transmittance, the sunlight transmittance and the ultraviolet transmittance (Tuv (ISO)) of the glass substrate are defined as Ya1, Tg1 and Tuv1, respectively. Rate and UV transmittance (Tuv (IS
O)), the values of Ya2, Tg2, and Tuv2 are defined as visible light transmittance, sunlight transmittance, and ultraviolet transmittance of the three-layer film itself, respectively (Ya2 / Ya1), (Tg).
2 / Tg1) and (Tuv2 / Tuv1),
In Examples 13 to 17, (Ya2 / Ya1) is 90% or more, (Tg2 / Tg1) is 82% or less, and (Tuv2
/ Tuv1) having a performance of 40% or less can be obtained.

Comparative Example 3 A of A4 used in Example 13
Example 13 was carried out in the same manner as in Example 13 except that the solution A of A13 in Comparative Example 1 was used instead of the solution. The obtained ultraviolet absorbing glass has a geometric thickness of 123 nm for the first layer, 159 nm for the second layer, and 109 nm for the third layer. The ultraviolet transmittance at a wavelength of 370 nm of the glass with the obtained film is 2 nm.
8.6%, Tuv (ISO) was 25.5%, and visible light transmittance was 75.0%. The sunlight transmittance is 66.7%, and the value of (Tg2 / Tg1) is 91.9%.
And Example 13 [sunlight transmittance is 58.6%,
(Tg2 / Tg1) value was 80.7%]. The color tone in transmission and reflection was almost the same as that of the substrate.

Comparative Example 4 A of A4 used in Example 13
Example 13 was carried out in the same manner as in Example 13 except that the solution A of A14 in Comparative Example 2 was used instead of the solution. The visible light transmittance of the glass with the obtained film is 78.4%, and the solar light transmittance is 6
0.1%. The transmittance at 370 nm is 54.
3%, Tuv (ISO) is 50.6%, (Tuv
v2 / Tuv1) was 94.8%, which was obtained in Example 13.
[Tuv (ISO) was 19.4%, and the value of (Tuv2 / Tuv1) was 36.3%]. The color tone in transmission and reflection was almost the same as that of the substrate.

[0045]

As described above in the detailed description of the invention,
According to the present invention, a high-refractive-index film having a very high refractive index is provided, and an ultraviolet-absorbing heat-ray reflecting glass having high heat-ray reflecting performance can be obtained while maintaining a high visible light transmittance.

[Brief description of the drawings]

FIG. 1 is a graph showing the composition of an optical thin film of the present invention.

Claims (11)

[Claims] 1. An optical thin film comprising titanium oxide, cerium oxide and bismuth oxide. 2. The optical thin film according to claim 1, wherein the contents of the titanium oxide, cerium oxide, and bismuth oxide are coordinate points (TiO _{2) of a} molar ratio of TiO ₂ , CeO ₂ , and Bi ₂ O ₃ in terms of oxide. Mol%, CeO ₂ mol%, Bi ₂ O ₃
Mol%), A (4,1,95), B (98,1,1), C
An optical thin film having a ratio within the range of a square ABCD consisting of (20,79,1) and D (3,14,83). 3. The optical thin film according to claim 1, wherein the contents of the titanium oxide, cerium oxide and bismuth oxide are coordinate points (TiO _{2) of the} molar ratio of TiO ₂ , CeO ₂ and Bi ₂ O ₃ in terms of oxide. Mol%, CeO ₂ mol%, Bi ₂ O ₃
Mol%), E (36,9,55), F (77,20,3),
Square EFG consisting of G (39,59,2) and H (24,38,38)
An optical thin film having a ratio in the range of H. 4. The optical thin film according to claim 1, wherein the contents of the titanium oxide, cerium oxide and bismuth oxide are coordinate points (TiO _{2) of the} molar ratio of TiO ₂ , CeO ₂ and Bi ₂ O ₃ in terms of oxide. Mol%, CeO ₂ mol%, Bi ₂ O ₃
Mol (%), I (54,23,23), J (68,29,
3) An optical thin film having a ratio within the range of a square IJKL consisting of K (49,48.5,2) and L (39,39,22). 5. A solution containing a titanium compound composed of a titanium alkoxide, a titanium alkoxide chloride or a titanium chelate, a cerium inorganic salt or a cerium compound composed of a cerium alkoxide and a bismuth compound composed of a bismuth inorganic salt or a bismuth alkoxide is placed on a substrate. The optical thin film according to any one of claims 1 to 4, wherein the optical thin film is obtained by coating the composition on a substrate and heating the composition at 400 to 800 ° C. 6. An optical thin film forming composition obtained by mixing and dissolving a titanium compound, a cerium compound and a bismuth compound in an organic solvent. 7. The titanium compound, the cerium compound and the bismuth compound are converted into TiO ₂ , CeO ₂ and Bi ₂ O ₃ , respectively, and coordinate points (TiO ₂ mol%, CeO ₂ mol%) of their oxide conversion molar ratios are converted. ₂ mol%, expressed as Bi ₂ O ₃ mol%), A (4,1,95), B (98,1,1), C (2
7. The composition for forming an optical thin film according to claim 6, wherein the composition is mixed and dissolved in a ratio within the range of a square ABCD comprising (0,79,1) and D (3,14,83). 8. A layer of a high-refractive-index film and a layer of a low-refractive-index film are alternately laminated on a transparent glass substrate in a total of at least three layers, and at least two of the at least three layers are high. An ultraviolet ray absorbing heat ray reflective glass, which is a refractive index film, wherein at least one of the high refractive index films is the optical thin film according to any one of claims 1 to 5. 9. The high refractive index film has a thickness of 170 to 500 nm.
The ultraviolet ray absorbing heat ray reflective glass according to claim 8, which has an optical film thickness of: 10. The ultraviolet ray absorbing heat ray reflective glass according to claim 8, wherein the low refractive index film has a refractive index of 1.6 or less and has an optical thickness of 170 to 500 nm. 11. The method according to claim 8, wherein the transparent substrate is a colored glass plate having a thickness of 2.0 to 5.0 mm and an ultraviolet transmittance (TUV (ISO)) of 10% or less. The ultraviolet absorbing heat ray reflective glass as described in the above.