JPH08179101A - Glass with optical thin film and its production - Google Patents

Abstract

PURPOSE: To obtain a glass plate having a thin film of which thickness is graded within a specified value in the vertical direction by applying a flow coating method and to make this plate applicable to windshield for automobile as well. CONSTITUTION: This glass plate with on optical thin film is obtd. by providing the surface of the transparent glass plate with thin film layer of graded film thickness increased or decreased in the thickness of at least one layer of the optical thin films in such a manner that the vertical film thickness difference of the thin film change gradually in a perpendicular direction at a value selected within 100nm with respect to a distance 100cm in the perpendicular direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass with an optical thin film in which a thin film layer having a specific thickness is formed on one surface of a glass plate by a flow coating method which is a wet coating method using a solution for film formation. Regarding manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as a uniform film forming method on a substrate using a wet method, spin coating, dip coating, spraying, roll coating, flow coating and brush coating, pad printing or paste is used. Although there are printing methods and the like, many efforts have been made so far in order to obtain a uniform thin film having a uniform film thickness. For example, the optical characteristics are sequentially changed along one direction of the substrate. There have been few studies on the preparation of such a thin film having a gradient film thickness.

Further, generally, in dipping, nozzle coating, spraying, etc. in which a substrate is set up and a film is formed, a liquid sagging phenomenon may occur between the film formation and the film drying, resulting in film unevenness.

Therefore, Japanese Patent Application Laid-Open No. 1-
In Japanese Patent No. 43368, a thin film coating method and apparatus are proposed, in which a container is filled with a coating solution to a predetermined level in a state where an opening surface of a container having one side opening is closely attached to a glass substrate, and then a predetermined coating liquid is applied. A method for extracting at a speed is described.

Further, for example, in Japanese Patent Application No. 5-127211 filed by the applicant of the present invention, a film forming method is proposed, and the substrate is raised slightly obliquely from the horizontal depending on the size of the substrate or the film forming area. Incline up and down freely, and at least on the upper surface side of the substrate, 1
The side surface of the container is opened and the container is in close contact with the solution, and the container in the close contact state is filled with the solution to a level according to the size of the substrate or the film formation area. Then, the container filled with the solution remains in close contact with the substrate. In order to control the rising speed according to the film thickness so that the solution level moves as the upper opening side of the container rises, the tilted substrate is rotated and coated until the solution is released from the substrate. The thickness of the film is controlled from either the film formation start side or the film formation end side so as to gradually attenuate within a certain width from a predetermined thickness or to a predetermined thickness.

Further, for example, in Japanese Patent Application No. 6-148938 filed by the applicant of the present invention, a thin film coating method is proposed, in which the deposition surfaces of two substrates are placed in parallel so as to face each other.
Spacers are placed around the three sides of both sides and the lower side of the substrate to provide a space, and the substrate and the spacer are brought into close contact with each other, and the coating solution is supplied from the supply / drain port that opens only one surface of the upper side formed by the close contact. It is described that the film is put to a predetermined level, then the solution is withdrawn from the supply / drainage port at a speed according to the predetermined film thickness, the film forming tank is disassembled, and the film substrate is taken out to form a film. The thickness of the film can be controlled to be gradually attenuated from a predetermined thickness or to a predetermined thickness within a constant width from either side of the film end.

In addition, for example, a thin film coating apparatus disclosed in Japanese Patent Laid-Open No. 6-218311 is disclosed.

[0008]

Problems to be Solved by the Invention In the above-mentioned thin film coating method and apparatus described in, for example, Japanese Patent Application Laid-Open No. 1-43368, and the film forming method described in Japanese Patent Application No. 5-127211, for example, an automobile is used. Although it is sufficiently suitable for uniformly forming a thin film having a small area on a windshield for use in a car, it is difficult to apply it to a device for forming a film on the entire surface of a windshield.

Further, for example, in the thin film coating method described in Japanese Patent Application No. 6-148938, although a thin film having a graded film thickness can be made practical enough, it has a complicated shape and can be mass-produced and the tact time can be improved. It is not always sufficient when productivity is required.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is one of the methods of leaning a glass plate to deposit a film. In the nozzle flow coating method in which a solution is made to flow from the upper part of a film to form a film, if the concentration and viscosity of the solution and the leaning angle of the glass plate are controlled, the change in the upper and lower film thicknesses (Δt) is almost constant. A thin film with a slope is obtained,
It is a thin film with a gradient film thickness that can be used for automobile window glass, etc.
For example, by using it as a reflection reduction film applied to the windshield of an automobile, it is possible to secure a high reflection reduction performance in a wider field of view of the driver, so that the glare can be suppressed in a wider range, and no misidentification or discomfort appears. The present invention provides a useful glass with an optical thin film such as Uru and a method for producing the same.

That is, according to the present invention, in an optical thin film formed on the surface of a transparent glass plate, the difference in film thickness between the upper and lower sides of the thin film is selected in a vertical direction at a value selected within 100 nm with respect to a vertical distance of 100 cm. A glass with an optical thin film, characterized by comprising at least one of the optical thin films having a graded thin film layer which is increased or decreased so as to gradually change.

In addition, in a flow coating method for forming an optical thin film by surface-flowing a thin film forming solution from the upper end of a glass plate which is vertical or has a predetermined inclination angle, the solute concentration and the viscosity of the solution. In addition, at least one of the leaning angles of the glass plate-like body is selected and controlled so that the vertical film thickness difference of the optical thin film formed on the glass plate-like body is 100 nm with respect to the vertical distance of 100 cm.
A method for producing glass with an optical thin film, characterized in that the value is selected within the range.

Further, after the solution is made to flow down on the entire surface and the solution is spread over the entire surface, a drying step is further performed in which the glass plate is tilted at a predetermined angle with respect to the horizontal direction. Manufacturing method of glass with thin film.

Further, the thin film forming solution is a sol-gel coating solution containing at least one organic metal compound or its hydrolysis and a solvent, and the solute concentration in terms of oxide in the solution is 0.01 mol / l. 5 mol / l
And a solution having a viscosity of 0.1 to 100 cP, respectively.

Here, at least one layer of the optical thin film is increased so as to gradually change in the vertical direction by a selected value within 100 nm with respect to a vertical distance of 100 cm for the vertical thickness difference of the thin film. Or, it is assumed that the glass is provided with a thin film layer with a reduced film thickness, for example, the film thickness difference between the upper and lower parts of the thin film is gradually increased in the vertical direction to exceed 100 nm with respect to the vertical distance of 100 cm. When it comes to change,
This is because the in-plane distribution of the film thickness in the glass plate, especially the uniformity of the film thickness in the lateral direction is gradually impaired, and not only the reflection reducing effect is lost but also an optical discomfort may occur. At least one layer of the thin film is increased or decreased in order to exhibit the optical characteristics such as optimum reflection reduction according to the mounting angle and the viewing angle of the driver in the window glass for automobiles. This is because it may be necessary to appropriately combine one or more layers.

In the flow coating method, at least one or more of the solute concentration and viscosity of the solution and the leaning angle of the glass plate-shaped body are selected and controlled by, for example, the shape of the glass plate-shaped body. , The size and thickness or the thin film forming solution to be used are appropriately selected and combined to secure the uniformity of the film thickness distribution in the gradient film thickness, and prevent the occurrence of cracks and pinhole-like defects in the thin film after firing. , To obtain a stronger thin film.

Further, the glass plate is accompanied by a drying step in which the solution is spread on the entire surface after the solution is allowed to flow down and the glass plate is tilted at a predetermined angle with respect to the horizontal direction. Depending on the shape and size of the thin body or the properties of the thin film forming solution used, the so-called liquid sagging phenomenon is prevented between the coating film and the cure, and the desired gradient film thickness is maintained normally, and there is no film unevenness. This is to obtain the highest graded thin film.

Further, the solution for forming a thin film is a sol-gel coating solution containing at least one or more organic metal compound or its hydrolysis and solvent, for example, among metal alkoxide compounds or metal acetylacetonate compounds. Using at least one compound or two or more compounds, it is stable, it is easy to control the average molecular weight when preparing a solution, and it is excellent in abrasion resistance, durability and optical properties. This is because it can be obtained at a low cost.

For example, as the metal alkoxide compound, when only an alkoxy group is bonded to all metal atoms, that is, not only methoxide, ethoxide, isopropoxide and the like, but also a part thereof is substituted with a methyl group, an ethyl group and the like. For example, it may contain monomethyl alkoxide, monoethyl alkoxide, or the like, or may be partially substituted with halogen such as chlorine. The metal acetylacetonate compounds include not only compounds in which only acetylacetone groups are bonded to all metal atoms, but also compounds in which some of them are substituted with alkoxy groups such as methylalkoxy groups and ethylalkoxy groups.

Further, the metal may be Si, Ti or Zr.
It is preferable to select, for example, tetramethoxysilane, tetraethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, titanium tetraisopropoxide, titanium monochlorotriisopropoxide, and titanium. Acetyl acetonate, zirconium normal butoxide, zirconium acetyl acetonate and the like are preferable, and other examples include dimethyldiethoxysilane, dimethyldimethoxysilane, titanium tetranormal butoxide, zirconium tetraisopropoxide, zirconium tetraoctylate and the like.

Further, regarding hydrolysis, the type of catalyst (for example, hydrochloric acid, nitric acid, acetic acid, maleic acid, etc.), the amount of addition thereof, that is, the PH value (for example, PH = 1 to 6, preferably 2 to 2).
5) and reaction temperature (for example, 20 to 80 ° C, preferably 25 to 80 ° C)
70 ° C) and the like to control the hydrolysis reaction process. Depending on the compound, the reaction time and the like may be different and may not necessarily be common to all. Further, as the alcohol solvent (solvent) in the present alcohol solution, methyl alcohol, ethyl alcohol, isopropyl alcohol or butyl alcohol, and polyhydric alcohol such as methoxypropanol can be adopted.

Further, the reason that the solute concentration in terms of oxide in the solution for forming a thin film is 0.01 mol / l to 5 mol / l means that a thin film is difficult to form if the solute concentration is less than 0.01 mol / l.
When it exceeds 5 mol / l, for example, in the nozzle flow coating method, the amount of the solution applied to the surface of the glass plate during film formation is larger than in the dipping method, so that the film thickness tends to become thick and uneven film thickness is likely to occur. In addition, cracks may be generated or peeled off when dried.

The viscosity of the solution is determined to be 0.1 to 100 cP because when it is less than 0.1 cP, the difference between the upper and lower film thickness is unlikely to occur, and a normal thin film is difficult to be formed. This is because the thickness difference becomes large, but it becomes difficult to control, the in-plane film thickness distribution becomes very poor, and the drying of the coating film becomes slow, and white turbidity, a crack phenomenon, and peeling easily occur during drying. A more preferable viscosity is about 1 to 10 cP. There is also the use of thickeners.

Further, the film firing of the glass plate-like body with a thin film having a gradient film thickness after the coating is preferably carried out appropriately in each step such as in-line heating and bending treatment and / or air-cooling strengthening treatment. .

Further, as the thin film of the gradient thin film layer, Si is used.
It is preferable to be composed of one or more of O ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , and B ₂ O ₃ , and SiO ₂ (1.
45), or TiO ₂ with a relatively high refractive index (about 2.25), ZrO ₂ (about 1.95) and SiO ₂ with a relatively low refractive index (1.
45), Al ₂ O ₃ (about 1.65), and B ₂ O ₃ (about 1.60) are mixed in various ways to freely control the refractive index as needed. 1.8
The following thin film should be used, and the durability should be excellent.

Further, the glass plate may be either colorless or colored as long as it is transparent glass, that is, for example, blue, bronze, gray or green glass, etc. In particular, it is a blue-colored glass or window material for automobiles. It is more preferable that the color tone is a gold color system, a green color system, and especially a green color system or a gold color system, so that it is easy to obtain the heat ray / ultraviolet absorption performance. It goes without saying that it can be used not only as a single plate, but also as a heat ray reflective glass, a multi-layered or laminated glass, a strengthened glass, a strength-up glass, a bent glass and the like. Furthermore, it goes without saying that the glass substrate may be inorganic or organic.

[0027]

As described above, the glass with an optical thin film of the present invention and the method for producing the same specify the difference in the thickness of the thin film on the surface of the transparent glass plate within 100 nm with respect to the vertical distance of 100 cm. The specified condition is defined by the provision of a thin film layer having a gradient thickness in which at least one of the optical thin films is increased or decreased so that the selected value gradually changes in the vertical direction. By controlling the manufacturing method so as to provide a thin film layer with a gradient film thickness of the specified value, even in a large area glass plate such as window glass for automobiles and window glass for construction, basically no masking is required In addition, there is no unevenness in the film thickness distribution along the gradient film thickness, and it is possible to give a gradient function to the optical properties with excellent film thickness controllability, resulting in a film that is optically uniform, homogeneous, and rich in variations, and cracks. Or It is a high quality film with no defects such as separation or turbidity, and liquid sagging phenomenon, and a thin film with excellent adhesion resistance and durability due to strong adhesion, saving the amount of film forming solution compared to the conventional method. It is possible to provide a glass with an optical thin film and a method for producing the same, which is simple, stable, reliable, and has no complicated steps, is highly productive, can be produced more efficiently, and is useful in a wide range of fields.

Further, for example, if it is adopted on the inside of the vehicle as a reflection reducing film of a windshield for automobiles, the reflection of the dashboard on the windshield when viewed from the inside of the vehicle can be effectively reduced according to the incident angle. For automobiles, it can suppress glare, improve transparency by suppressing reflections, prevent misidentification and discomfort, and have high durability, which is friendly to the occupants such as drivers and people and the environment. It will be an excellent glass with an optical thin film as a window material, and other new optical products.

[0029]

The present invention will be described below in detail with reference to examples. However, the present invention is not limited to the embodiment.

Example 1 Si alkoxide and Ti alkoxide were mixed so that the molar ratio in terms of oxide was 95: 5, a small amount of water and an acid catalyst were added and hydrolyzed, and this was further mixed with isopropyl alcohol. Then, the solute concentration in terms of oxide was diluted to about 0.04 wt% and the mixture was stirred for about 1 hour. The viscosity of this solution is about 2.
It was 4 cP. This solution was put into a washing bottle to give a coating solution.

Next, in a clean room kept at a temperature of about 25 ° C. and a humidity of about 55%, a glass plate having a length of about 1 m, a width of 1.5 m, and a thickness of about 2 mm was set at an angle (tilt angle) from the horizontal. )But
The coating solution in the washing bottle was flown down along the upper end of the glass plate at a constant pressure so as to be 10 °, and a coating film was formed on almost the entire one surface of the glass plate. Even after the entire solution flowed down on the glass plate, the coating film was kept as it was for about 10 minutes so that it was sufficiently dried.

The glass plate body with a coating film thus obtained was once about 2
After being placed in a dryer at 50 ° C. for curing for about 30 minutes, it was further placed in a baking furnace whose ambient temperature was kept at about 650 ° C. and baked for about 90 seconds.

The obtained SiO ₂ TiO ₂ film-coated glass plate was sufficiently cooled and the thickness of the thin film was measured. At a position 150 mm from the upper end of the glass plate, 37 to 38 nm and 450 mm were measured.
The film thickness gradually increases from 46 to 48 nm and 57 to 58 nm at the position of 750 mm, and the rate of increase is about 20 nm with respect to the vertical difference of 60 cm. A plate-shaped body could be obtained.

Example 2 A solution obtained by mixing and hydrolyzing an Si alkoxide and a Ti alkoxide prepared in Example 1 was further added, and the solute concentration in terms of oxide was about 0.03 wt% with isopropyl alcohol.
The resulting solution was diluted with water and stirred for about 1 hour, and then placed in a washing bottle to give a coating solution. The viscosity of this solution was about 2.1 cP.

Next, in a clean room kept at a temperature of about 25 ° C. and a humidity of about 55%, the same as in Example 1, the vertical length is about 1 m,
A glass plate with a width of 1.5 m and a thickness of about 2 mm is laid on a support so that the angle (tilt angle) from the horizontal is 80 °, and the coating solution in the washing bottle is placed on the top of the glass. It was made to flow down along a part with a constant pressure, and the coating film was formed on substantially the entire one surface of the glass plate. Even after all the solution had flowed down on the glass substrate, it was kept as it was for about 15 minutes so that this coating film was sufficiently dried.

The obtained coated glass plate was used in Example 1.
The same heat history process was performed. The obtained glass plate with SiO ₂ / TiO ₂ film was sufficiently cooled and the thickness of the thin film was measured. As a result, about 35 nm and 45 nm were measured at a position 150 mm from the upper end of the glass plate.
The film thickness gradually increases from 56 to 58 nm at the 0 mm position and from 84 to 86 nm at the 750 mm position.
A glass plate having a thickness of 40 nm and having a desired thin film layer having a gradient film thickness could be obtained.

Example 3 A commercially available silica sol solution prepared using an alkoxide of Si as a starting material [eg, "Colcoat P" manufactured by Nippon Corcoat Co., Ltd., or "Atron NSi" manufactured by Nippon Soda Co., Ltd.] was mixed with ethyl alcohol and ethyl acetate. The mixture was diluted with a mixed solution of normal butyl alcohol and 0.1 mol / l and stirred for about 30 minutes. The viscosity of this solution was about 3.0 cP. This solution was put into a washing bottle to give a coating solution.

Next, in a clean room kept at a temperature of about 27 ° C. and a humidity of about 50%, a glass plate having a length of about 50 cm, a width of 50 cm, and a thickness of about 1.1 mm was set at an angle (tilt angle) from the horizontal. )But
The coating solution in the washing bottle was caused to flow down along the upper end of the glass plate at a constant pressure so as to be 80 °, and a coating film was formed on almost the entire one surface of the glass plate. After all the solution flowed down on the glass plate, the glass substrate was tilted so that the tilt angle was 45 °, and the coating film was held for about 8 minutes so that it was sufficiently dried.

The glass plate with a coating film thus obtained was once about 2
After being placed in a dryer at 50 ° C. for curing for about 30 minutes, it was further placed in a baking furnace whose ambient temperature was kept at about 550 ° C. and baked for about 15 minutes.

The obtained glass plate with a SiO ₂ TiO ₂ film was sufficiently cooled and the film thickness was measured. The film thickness gradually increased from the upper part to the lower part of the glass plate. ,
About 30 nm at a position 75 mm from the upper end of the glass plate and about 55 nm at a position 375 mm from the upper end of the glass plate, and the rate of increase was about 25 nm for a vertical difference of 30 cm. It was possible to obtain a glass plate having a desired thin film layer having a gradient film thickness.

[0041]

As described above in detail, the present invention provides a glass with an optical thin film having at least one specified thin film layer with a gradient film thickness, a solute concentration of a solution, a viscosity, and a condition of a tilt angle of a glass plate. By adopting a manufacturing method that controls to a specified thin film layer with a graded film thickness, it is possible to provide a graded function with excellent optical characteristics even in a large-area, high-grade glass plate, and it has high quality and durability. It is possible to produce a thin film with good properties on one side without masking, simply, stably, reliably and speedily and efficiently, and when applied to automobile window glass, etc. It is useful in a wide range of fields, such as improved transparency, preventing eye fatigue, etc., and improving safety, and being friendly to both human and physical aspects and the environment. Those capable of providing a university with a thin film glass and its manufacturing method.

Claims (4)

[Claims] 1. In an optical thin film formed on the surface of a transparent glass plate, the difference in film thickness between the upper and lower parts of the thin film is measured by a vertical distance.
It is characterized by comprising at least one of the optical thin films having a gradient thin film layer which is increased or decreased so as to gradually change in the vertical direction at a selected value within 100 nm with respect to 100 cm. Glass with optical thin film. 2. A solute concentration and viscosity of the solution in a flow coating method in which an optical thin film is formed by surface-flowing a thin film-forming solution from the upper end of a glass plate which is vertical or leans against a predetermined inclination angle. In addition, at least one of the inclination angles of the leaning of the glass plate is selected and controlled, and the vertical film thickness difference of the optical thin film formed on the glass plate is selected within 100 nm for a vertical distance of 100 cm. A method for producing glass with an optical thin film, which is characterized in that 3. A drying step, which is carried out after the solution is spread on the entire surface by allowing the solution to flow down on the surface and further tilting the glass plate at a predetermined angle with respect to the horizontal direction. A method for producing glass having an optical thin film as described above. 4. The thin film-forming solution is a sol-gel coating solution containing at least one organic metal compound or its hydrolysis and a solvent, and the solute concentration in terms of oxide in the solution is 0.01 mol / l to 4. The method for producing a glass with an optical thin film according to claim 2, wherein the viscosity of the solution is 5 mol / l and the viscosity of the solution is 0.1 to 100 cP.