JPH06340450A - On-vehicle windshield - Google Patents

Abstract

PURPOSE:To increase the transmittance of the front windshield, to lower its reflectivity and to improve its see-through property, safety and durability by forming a low- reflection thin film having a specific structure on the front surface of a planar glass body. CONSTITUTION:The front surface side of an inner glass plate 3 of the on-vehicle windshield is coated with the thin film 5 of a first layer having a middle refractive index and is coated thereon with the thin film of a refractively high refractive 6 index and further thereon with the thin film 6 of a low refractive index in this order. The prescribed region of the low-reflection thin film or the prescribed region where of the first layer thin film 5 of the refractive index higher than the relatively low refractive index of the outermost thin film 6 is exposed is coated with the fresh layer of the thin film, by which combiner glass 10 for a head up display (HUD) to be made copresent with the wavelength selective reflection film in the partial area in the wavelength selective reflection film or nonwavelength selective reflection film. Another layer of the fresh laminated thin films 11 is formed in the prescribed partial area within the region where the first layer of Fig. is exposed and outer glass plate 2 is superposed on the inner glass plate 3 with its film surface side as the exposed surface side, by which the on-vehicle windshield 1 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces, for example, the reflection phenomenon of the dashboard or the peripheral portion thereof which appears on the windshield when driving a vehicle, prevents the visual disturbance of the driver with sufficient transparency, and improves safety. Among them can contribute to the improvement of, part of it combines combine performance for heads up display (HUD),
The present invention relates to a useful window glass for a vehicle, which can display various kinds of information necessary for a driver or an occupant with good visibility and appropriately.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made and partially implemented for low reflection glass, glass with a combiner for HUD and glass belonging to the category. In particular, in window glass for vehicles, high-performance multi-function glass with various functionalities has been used in recent years, and it is safer not only for drivers and passengers in the vehicle but also for oncoming vehicles. In the midst of the ever-increasing demand for products that are highly habitable and environmentally friendly,
Glasses having the above-mentioned low reflection or the above combiner and the properties belonging to the category have been proposed, respectively.

Particularly, in a conventional low reflection film used for a windshield mounted on a vehicle window at a specific inclination angle,
The purpose is to reduce the reflected light from the front, the angle of incidence with the vertical line of the windshield surface (hereinafter referred to as the normal), for example, for oblique incident light of 50 ° ~ 70 ° or more,
The low reflection effect is reduced to half or almost none.For example, when the driver's dashboard or surrounding objects are reflected on the windshield, the visibility of the foreground during driving decreases and the safety is reduced. It will be expressed.

On the other hand, for example, Japanese Patent Application Laid-Open No. 3-17601 describes a method of forming an antireflection coating, in which a coating of a reactive composition containing a light metal oxide precursor, a non-aqueous solvent, and water is used as a substrate. Formed on, heated and concentrated for a sufficient time, and exposed the concentrated coating to an atmosphere containing fluorine gas or a fluorine-producing gaseous compound at an elevated temperature for a sufficient time to oxidize the coating light metal. By substituting at least a part of the oxygen atoms of the substance with fluorine atoms, a coating having a light metal fluoride concentration gradient with respect to the coating thickness and exhibiting excellent antireflection performance for the entire visible light spectrum can be obtained. What is to be obtained is disclosed.

As a laminate of two layers of antireflection film, for example, Japanese Patent Laid-Open No. 64-70701 discloses a transparent plate having a conductive antireflection film. In addition, the refractive index is 1.90 to 2.50 and the film thickness is 200 Å to 40
0 Å high-refractive-index dielectric film, and the refractive index on the surface is 1.35 ~
A low refractive index dielectric film having a film thickness of 1.50 and a film thickness of 700Å to 1200Å is disclosed.

Further, for example, Japanese Patent Application Laid-Open No. 4-357134, which has been filed by the present applicant, describes a vehicle reflection-reducing glass.
A thin film with a refractive index of 1.8 to 1.9 and a film thickness of 700 to 900Å, and then a thin film with a refractive index of 1.4 to 1.5 and a film thickness of 1100 to 1300Å are laminated to cover the glass surface at an incident angle of 50 to 70 °. It is disclosed that the rate is reduced by 4.5 to 6.5%.

Further, as a laminate of three layers of antireflection film, for example, Japanese Patent Laid-Open No. 61-189501 discloses a transparent low reflection plate, in which the three layers of antireflection film are closer to the substrate side than the air side. The refractive index of the antireflection film of the second layer is increasing from the substrate side toward the air side, and the refractive index of the first layer is n ₁ from the air side toward the substrate side. = 1.
30 to 1.45, the refractive index of the second layer is n ₂ = 1.95 to 2.15, and the refractive index of the third layer is n ₃ = 1.60 to 1.80. The optical thicknesses n ₁ d ₁ and n ₂ d _2, n ₃ d ₃ and each approximately _{n 1 d 1 = λ 0/} 4,
_{n 2 d 2 = λ 0/} 2, n 3 d 3 = λ 0/4 ( where lambda ₀ is the center wavelength) is disclosed to be.

Furthermore, for example, Japanese Patent Application Laid-Open No. 4-357135, which has been filed by the present applicant, describes a reflection-reducing glass for a vehicle, and one surface of the transparent glass substrate has a refractive index of 1.8 to 1.9. With a film thickness of 700 to 1000Å, a refractive index of 2.05 to 2.3 and a film of 1300 to 1600Å, and a film of a refractive index of 1.4 to 1.5 and a film of 1100 to 1300Å. 4.5 to 6.5 from the reflectance on the glass surface
It is known to disclose what is made by reducing it by%.

On the other hand, as a vehicle HUD combiner,
For example, Japanese Patent Application Laid-Open No. 1-43 which the applicant has already filed
No. 368 discloses a thin film coating method and apparatus therefor, or, for example, Japanese Patent Application Laid-Open No. 4-131530 discloses glass for multi-color display head-up display. .

[0010]

As described above, for example, in Japanese Patent Application Laid-Open No. 3-17601, the sol-gel technique is used to form a coating having a light metal fluoride concentration gradient with respect to the coating thickness. It is difficult to say that the method to do is necessarily highly efficient, productive and economical with complicated working steps. Further, for example, in those disclosed in JP-A-64-70701 and JP-A-61-189501, it is not always possible to obtain a sufficient and stable desired reflection reduction for the above-mentioned specific oblique incident light. Furthermore, it is difficult to say that both of them have the durability required for a vehicle.

Further, the ones described in the above-mentioned JP-A-4-357134 and JP-A-4-357135, which the applicant of the present invention has already applied, reduce visual obstruction due to glare of a dash board, for example, while driving a vehicle. It is useful to be able to.

Therefore, a thin film having a high reflectance is formed on a part of the surface of each of the various low reflection glasses described above by simply adopting, for example, JP-A-1-43368 or JP-A-4-131530. When a combiner for HUD is provided, interference with a low-reflection thin film may occur in some cases, resulting in a darker color and higher stimulus purity, resulting in a decrease in visible light transmittance, or as a combiner, the target characteristics are obtained. If the thin films are laminated in multiple layers of, for example, 5 layers or more, not only the appearance quality of the film is deteriorated, but also the film strength is easily deteriorated.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and for example, a thin film laminate in which two or three layers in which thin films having specified refractive indexes and film thicknesses are combined are coated. This allows, for example, the visible light transmittance of the windshield to be 70% or more, and the reflectance of the reflected light at a predetermined oblique incident light to be reduced by about 4.5 to 6.5%. A low-reflective thin film that does not cause a noticeable change in the color tone of the low-reflective thin film, or a predetermined region where the first thin film is exposed from the glass surface of the low-reflective thin film. By newly coating the laminated thin film on the
It is possible to provide an area suitable for a combiner at the same time, and to display various driving information with more excellent visibility and sensation, so that misidentification, discomfort, or eye fatigue does not occur. A window glass for a vehicle having safety and high durability.

That is, according to the present invention, in a low reflection thin film formed on the surface of a glass plate, in a predetermined region on the low reflection thin film or among the thin films constituting the low reflection thin film,
At least the first layer thin film is exposed in a predetermined region from the glass surface, and the predetermined region is made of a thin film having a refractive index higher than the relatively low refractive index of the outermost surface layer thin film, and the whole or partial region of the predetermined region. A window glass for a vehicle, characterized in that it is formed by coating at least one laminated thin film.

The window glass for a vehicle as described above, characterized in that the predetermined region in which the low reflection thin film is coated with at least one laminated thin film is formed of a wavelength selective reflection film.
Further, the predetermined region where at least the first thin film is exposed from the glass surface in the low reflection thin film is formed of a non-wavelength selective reflective film, and the entire region in which at least one layer of laminated thin film is covered on the predetermined region or A window glass for a vehicle as described above, characterized in that a partial region is made of a wavelength selective reflecting film.

Further, the above-mentioned window glass for vehicles is characterized in that the low reflection thin film is formed by coating and laminating two or three thin films having different refractive indexes. Furthermore,
The above-mentioned vehicle window glass is used as a combiner glass for heads-up display, respectively.

Here, the low reflection thin film is, for example, a two-layer low reflection thin film having different refractive indexes, and the refractive index n ₁ = 1.8 to 2.1 as the first layer from the glass surface side and the film. A thin film layer having a thickness of d ₁ = 700 to 2300Å is coated, and then a refractive index of n ₂ = 1.4 to 1.5 and a film thickness of d ₂ = as an outermost surface thin film layer on the first thin film layer. 1100 ~ 1300 Å is formed by coating and laminating thin film layers, and further, with respect to visible light incident on the film surface side at an incident angle between the vertical line of the surface and 50 ° ~ 70 °, in the thin film coating laminated surface The reflectance is 4.5 to 6.5% from the reflectance on a glass surface without a usual thin film coating.
It is made by reducing it.

Further, for example, a three-layer low-reflection thin film having different refractive indexes, where the first layer from the glass surface side has a refractive index of n ₁ = 1.8 to 1.95 and a film thickness of d ₁ = 700 to 1000Å A thin film layer is coated, and then a second film is formed on the first thin film layer.
As the second layer, the refractive index is n ₂ = 2.1 to 2.3 and the film thickness is d ₂ = 130
A thin film layer having a thickness of 0 to 1650Å is coated, and a refractive index n ₃ = 1.4 to 1. as an outermost surface thin film layer on the second thin film layer.
5 and a film thickness of d ₃ = 1100 to 1300Å is laminated by coating, and the incident angle with respect to the vertical line of the surface is 50.
With respect to visible light incident on the film surface side in the range of ° to 70 °, the reflectance on the laminated surface of the thin film coating is reduced by 4.5 to 6.5% from the reflectance on the glass surface without the ordinary thin film coating. .

Further, the first thin film is made of Si.
O ₂ (n = 1.45), TiO ₂ (n = 2.25), ZrO ₂ (n = 1.95)
)), Al ₂ O ₃ (n = 1.65), B ₂ O ₃ (n = 1.60), and a mixture of two or more of them. This is because by combining various kinds of materials having a relatively low refractive index and mixing them, it is easy to obtain a composite film having a refractive index of 1.8 to 2.1 that can be freely controlled, and the durability becomes excellent.

Furthermore, as the second thin film, Ti is used.
O _2, Ta ₂ O _5, either of ZrO _2, or SiO _2, TiO _2, Zr
It is composed of a mixture of two or more kinds of O ₂ , Ta ₂ O ₅ , Al ₂ O ₃ and B ₂ O ₃ , and in particular the adhesion to the first thin film and the third thin film. Is excellent, and the durability as a coated laminated thin film layer is also improved to be excellent. Furthermore, not only a single component but also those having high and low refractive indexes can be freely compounded and controlled in the same manner as described above. This is because it becomes easy to obtain the value of the required refractive index.

Furthermore, when a high refractive index thin film having a refractive index of about 2.3 or more is used and the thin film layer is made into a multi-layer thin film layer exceeding three layers, in particular oblique incident light, multiple Due to interference and the like, coloring and reflection tend to become stronger and stronger. For example, the visible light transmittance is 70% or more, or the reduction in reflection is difficult to reach a desired value. Unless the values of the refractive index and the film thickness of the second layer and the third layer thin film are skillfully combined with the above-mentioned specific values, the incident angle with the vertical line of the surface is between 50 ° and 70 °. For visible light on the film surface side, the reflectance on the laminated surface coated with the thin film cannot be reduced by 4.5 to 6.5% from the reflectance on the glass surface without the ordinary thin film coating, and it is assumed that extremely thin coloring is expressed. Almost in sight This is because it tends to be difficult to produce to the extent that it cannot be opened, and it is difficult to say that it has sufficient durability.

The incident angle with the vertical line of the surface is 50.
With respect to the visible light incident on the film surface side in the range of ° to 70 °, the reflectance on the laminated surface of the thin film coating is 4.5 to 6.5% lower than the reflectance on the glass surface without the ordinary thin film coating. Generally, the mounting angle of the windshield of an automobile is about 40 ° to 20 °, and the dashboard and its peripheral parts are reflected on the inner surface of the windshield to cause a phenomenon of reflection, which is not preferable for a driver or the like. This is because the incident angle of the light is 50 ° to 70 ° with respect to the vertical line of the surface. In addition, the reflectance is 4.5
If it is reduced by ~ 6.5%, it becomes difficult for the driver, etc. to visually recognize the above-mentioned reflection and it is not bothersome, and it is possible to reduce eye fatigue and mental irritation of the driver, etc. This is because it is possible to change a dashboard color tone whose main color is black to, for example, a lighter color tone, thereby making it more varied.

The reflectance of the reflected light also follows the change in the incident angle, and for example, the reflectance increases as the incident angle increases. In addition, the above-mentioned three-layer thin film stack has a lower reflectance of reflected light at normal incidence with respect to the film surface than the two-layer thin film stack, and for the reflected light lower than the incident angle, Not only is the effect of reducing reflection better than that of a thin layer of layers, but the stimulation purity can be suppressed to a low level depending on the combination of the thin layers, and a sense of discomfort can be eliminated from the outside of the vehicle.

Here, the newly coated laminated thin film has a refractive index of n ₄ = 2.0 to 2.5 and a film thickness of d ₄
= 500-2000Å is an oxide thin film, such as Ti
And an alkoxide sol composed of Si and / or Zr, and specifically, for example, TiO ₂ , TiO ₂ and SiO ₂ , or
It is an oxide thin film such as SiO ₂ and ZrO ₂ .

Further, at least 1 is formed on the low reflection thin film.
The reason that the predetermined area covering the laminated thin film of layers is made of the wavelength selective reflection film is that the non-wavelength selective reflection of the predetermined area in which at least the first thin film is exposed from the glass surface by the low reflection thin film. The entire area or partial area where at least one layer of laminated thin film is covered with a wavelength-selective reflective film has both the function of a low reflective thin film and a combiner for HUD, It is possible to obtain the target characteristics as the combiner while suppressing the interference with the reflective thin film to a slight degree, not producing a dark color, the stimulation purity is not high, and the desired high visible light transmittance is maintained. You can
Furthermore, the appearance quality of the film is not deteriorated, and the film strength is excellent.

Further, when it is used as a window glass for a vehicle, there is a legal regulation that a visible light transmittance of 70% or more is required, so that a metal thin film having an extremely high reflectance is used. In general, the refractive index is about 1.8-2.
An oxide single layer film of about 0 is used. The thin film having this refractive index is used as the first thin film from the glass surface of the above-mentioned low reflection glass. Therefore, in order to form a further low reflection film, it is formed on the first thin film. At least the second layer or the second and third layers are removed to expose the thin film of the first layer in a part of a predetermined area.
It is a combiner for HUD.

Further, the glass substrate 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 blue or gold for automobile window materials. It is more preferable that the color tone is a system color, a green color color, and particularly a gold color tone, which easily obtains 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.

Among them, laminated glass using at least colored glass is the most preferable window material for automobiles.

[0029]

As described above, the window glass for a vehicle of the present invention, for example, uses a thin film having a medium refractive index on the glass surface side and / or a thin film having a low refractive index of a low degree on the thin film, and then has a low refractive index. By combining the above thin films etc. to form a thin film stack of, for example, 2 layers or 3 layers, for example, the visible light transmittance in the windshield satisfies 70% or more and, for example, 50 ° to 70 ° from the dashboard etc. The reflectance of the light reflected from the inner surface of the glass can be reduced by about 4.5 to 6.5% with respect to the obliquely incident light that is incident at, and especially the reflection phenomenon of the dashboard or these peripheral parts is reduced, and The glass with a low-reflection thin film that enhances the transparency, has no glare when viewed from the inside and outside of the vehicle, and is suppressed to the extent that coloring is hardly present, and provides excellent transparency. A new laminated thin film is appropriately coated on a predetermined region of the reflective thin film or on a predetermined region where the first thin film on the glass surface side having a higher refractive index than the outermost surface thin film is exposed. By
It becomes the intended HUD combiner for coexistence of the wavelength selective reflection film in the partial area of the wavelength selective reflection film or the non-wavelength selective reflection film, and can display various or various displays that enhance the visibility and visibility of various driving information. It is a window glass for a vehicle that is not useful as a window material for an automobile, because it does not cause misidentification or discomfort and is highly durable and safe for passengers such as drivers. .

[0030]

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

Example 1 As shown in FIG. 1, the size is about 1.5 mx 1.0 m and the thickness is about 2 mm.
The inner glass plate 3, which was a bronze-colored float glass, was thoroughly washed with filtered water and dried by blowing dry air, and then only one side of this glass was covered with a masking tape.

The alkoxide of Ti and Si is converted into oxide in advance.
60 mol: 40 mol are mixed, further diluted with a solvent containing isopropyl alcohol as a main component so as to have a solid content concentration of about 3.0 wt%, sufficiently mixed and stirred, and then about 2 cP (for example, about 1 to 3 cP is preferable. The alkoxide sol solution of 1) was prepared.

Then, the inner glass plate 3 was immersed in the preparation solution, and then gently pulled up at a constant speed of about 3.8 mm / sec to form a film. After the pulling up was completed, the coating film was dried by standing for about 1 minute. Then, the masking tape on the back surface was gently peeled off, and the inner glass plate 3 was placed in a baking furnace having an ambient temperature of about 270 ° C. and baked for about 7 minutes to form the first thin film 5.

Next, the inner glass plate 3 is washed and dried in the same manner as described above, and the entire non-film-forming surface is again covered with a masking tape to cover it so that the solid content is about 6.0 wt% and about 2 cP. After gently immersing it in the Si alkoxide sol solution prepared (for example, about 1 to 3 cP is preferable),
The coating was performed by pulling up at a constant speed of about 3.2 mm / sec.
The inner glass plate 3 was allowed to stand for about 1 minute as in the case of the first layer to dry the coating film, and then the masking tape on the back surface was gently peeled off and removed to form the outermost surface layer thin film 6.

Further, the inner glass plate 3 is set on a screen for screen printing with the coating film side facing up, as disclosed in Japanese Patent Application Laid-Open No. 151238/1991 proposed by the present applicant. The alkoxide decomposition paste prepared by mixing water, polyethylene glycol, citric acid and a filler was applied to a predetermined area on the coating surface of the glass plate 3 where the HUD combiner was to be formed, using a 180 mesh nylon screen plate. Screen printed. The glass was placed again in a baking furnace having an ambient temperature of about 270 ° C. and baked for about 15 minutes. After that, a peeling treatment is performed to remove the alkoxide decomposition paste portion burned on the surface of the outermost surface thin film 6, which is the coating surface of the inner glass plate, using approximately 0.5N sodium hydroxide and 1N sulfuric acid aqueous solution.

In the predetermined area where the alkoxide-decomposing paste is removed by the peeling process, the outermost surface thin film 6 formed with the alkoxide of Si together with the paste is also removed. As a result, the inner glass plate 3 is Two layers of thin film systems having different refractive indexes are formed on the entire one surface, and the second outermost surface layer thin film 6 is not formed in a predetermined region of the thin film system, and the first layer thin film 5 is formed. It was exposed, and the HUD combiner section 10 was formed.

Then, after washing and drying the inner glass plate in the same manner as above, the solid content concentration was adjusted to about 4.5 wt% only in a predetermined partial area in the area where the first layer was exposed.
Using Ti alkoxide sol, another layered thin film 11 was newly formed by the pattern film forming method disclosed in the above-mentioned official gazette of the present applicant.

The outer glass plate 2 which is another float colorless glass with the film surface side of the inner glass plate 3 as the exposed surface side
It was piled up and supplied to a production line for manufacturing a vehicle windshield for bending and heating. Further, the glass was used as a laminated glass through a polyvinyl butyral film (PVB) 4 to obtain a vehicle window glass 1 which is a windshield with an automobile thin film.

Obtained vehicle window glass1Is the glass
When the thin film laminated part of was measured with an ellipsometer,
The first thin film 5 on the glass surface has a refractive index n.₁= 1.90 film
Thickness d₁= About 750Å TiO₂・ SiO₂Thin film, the second thin film
The outermost surface thin film 6 has a refractive index n ₂= 1.45 and film thickness d₂= About 1200
Å SiO₂It is a thin film.
For visible light incident at an incident angle θ of about 61 ° with the incident light,
The reflectance of the reflected light is about 10%, and a thin film layer is formed.
The reflectance is reduced by about 6% compared to the case without
It becomes a low reflection film, and the visible light transmittance is about 83-84%.
there were.

On the other hand, in the HUD combiner portion 10 which is the above-mentioned predetermined region, the portion where the TiO ₂ .SiO ₂ thin film which is the first thin film 5 is exposed has a visible light reflectance of about 19% and a visible light reflectance of about 19%. The transmittance was about 72-73%, and the optical characteristics required as a non-wavelength selective reflection combiner for HUD (hereinafter referred to as neutral combiner), which showed almost flat reflection characteristics in the visible region, were exhibited. Furthermore, in the laminated thin film portion where a thin film is further formed on the exposed first layer, there is a peak at around 530 nm for visible light with an incident angle θ = 61 ° and the reflectance is about 24%. It is a selective reflection film that selectively reflects the green color, and exhibits the characteristics of a wavelength selective reflection combiner. Further, when the durability of the thin film portion of the glass was examined, it was found to have all the durability such as abrasion resistance and chemical resistance required as a window glass for vehicles.

Example 2 In the same manner as in Example 1, as shown in FIG. 2, a first thin film 7, which is a thin film similar to that in Example 1, was formed on only one surface of the glass plate. The pulling rate of the glass plate during film formation is about 3.8 mm / sec.

Then, on the same surface as that on which the first thin film 7 was formed, the alkoxide of Ti as the second thin film was diluted with isopropyl alcohol so as to have a solid content concentration of about 5.0 wt% and sufficiently stirred. Using the alkoxide sol solution thus prepared, the same film formation as in Example 1 and a drying operation were performed. At that time, the pulling speed of the glass plate is about 3.6 mm /
The second thin film 8 is formed as shown in FIG. Next, only a part of the predetermined region was etched by the same method as in Example 1 to peel off only the second layer thin film 8.

Then, as the third thin film, the first
On the same surface side where both the thin films of the second layer and the second layer were formed, the inner glass plate 3 was pulled up with the same Si alkoxide sol solution as that used for the second thin film of Example 1. The film was formed at a speed of about 3.3 mm / sec, and then the same region where the second layer thin film was peeled off was processed by the same method as the second layer thin film peeling process, The eye thin film was peeled off and dried at about 270 ° C. for 15 minutes to obtain the outermost surface thin film 9 as the third thin film as shown in FIG.

Furthermore, the second and third layers are removed, and the first embodiment is formed over the entire predetermined region where the first layer is exposed.
The laminated thin film 11 was formed with the same Ti alkoxide sol as in Example 1 by the method previously proposed and proposed by the present application.

Then, in the same manner as in Example 1, 3
The inner glass plate 3 on which the layer coating film was formed was used as a laminated glass in the same manner as in Example 1 to obtain a vehicle window glass 1 which was a windshield with an automotive thin film as shown in FIG.

Obtained window glass for vehicle1Is the glass
Using the ellipsometer, as in Example 1,
As a result of measurement, the thin film 7 of the first layer on the glass surface side was refracted.
Rate n ₁= 1.90 and film thickness d₁= 750 Å TiO₂・ SiO₂Thin film, first
The second layer of thin film 8 has a refractive index n₂= 2.20 and film thickness d₂= About 1200Å
TiO₂The outermost surface thin film 9 which is the thin film and the third thin film is bent.
Folding rate n₃= 1.45 and film thickness d₃= About 1250Å SiO₂Become a thin film
And the incident angle θ with the vertical line to the film surface is about 61 °
The reflectance is about 11% with respect to the incident visible light,
Reflection of the reflected light compared to the case where no film layer is formed
The rate was reduced by about 5%, resulting in a low reflection film.

Further, the thin films of the second and third layers are removed,
Further, on the portion on which a new laminated thin film 11 is formed, the selective reflection characteristics similar to those of Example 1 are shown with respect to the visible light with the incident angle θ = 63 °, and it is necessary as a wavelength selective reflection combiner for HUD. It has excellent optical properties. Further, when the durability of the thin film portion of the glass was examined, it was found that, as in Example 1, it also possessed all the durability such as abrasion resistance and chemical resistance required for a window glass for a vehicle.

Example 3 In the same manner as in Example 1, the same solution as used in Example 1 was used to form a two-layer thin film on the entire surface of one surface of the float glass in the same order.

However, only in the film formation of the first layer, the glass pulling speed was changed to about 4.0 mm / sec. The same alkoxide sol of Ti as that used in Example 1 and Example 2 was used only in a predetermined region on the side where the glass thin film thus obtained was formed, and the example previously proposed by the applicant was proposed. The laminated thin film 11 was formed by the method disclosed in the publication described in 1.

Further, the obtained glass was made into a laminated glass by the same operation as in Examples 1 and 2, and was prepared as shown in FIG.
Window glass for vehicles that is a windshield with a thin film for automobiles
Got 1 .

When the obtained window glass 1 for a vehicle was measured by an ellipsometer in the same manner as in Example 1, the first thin film 5 on the glass surface side had a refractive index n ₁ = 1.90 and a film thickness d ₁ = About 8
TiO ₂ · SiO ₂ thin film of Å, the outermost surface layer film 6 is a thin film of the second layer has a SiO ₂ thin film having a thickness d ₂ = about 1200Å in refractive index n ₂ = 1.45, a further predetermined area The formed thin film of the third layer is a TiO ₂ thin film having a refractive index n ₃ = 2.20 and a film thickness d ₃ = about 1000Å, and in a portion where only two thin films are formed, a line perpendicular to the film surface is formed. The reflectance of visible light incident at an incident angle θ of about 61 ° is about 10%, and the reflectance of that reflected light is higher than that of glass without a thin film layer under the same conditions. The reflectance was reduced by about 6%, resulting in a low reflection film.

On the other hand, in a predetermined region of the laminated thin film 11 in which another thin film is formed, the same reflection characteristic for 61 ° incident light as described above exhibits selective reflection characteristic having a reflection dominant wavelength at about 530 nm. The visible light reflectance was about 36%. In addition, the visible light transmittance of the region is about 71%,
° We showed the optical characteristics required for a wavelength selective reflection combiner for HUD that selectively reflects green light to incident light.
Further, when the durability of the thin film portion of the glass was examined, it was found that both the low reflection film portion and the combiner portion had all the durability such as abrasion resistance and chemical resistance required as a window glass for a vehicle.

The film forming method in the present invention may be, for example, a spin coating method in addition to the dipping method.
In particular, the laminated thin film may be formed by screen printing or the like. Needless to say, the viscosity and the like are adjusted variously according to each film forming method or film forming condition.

[0054]

As described above, according to the present invention, for example, the visible light transmittance is reduced by the low reflection thin film composed of two or three layers in which thin films having the specified refractive index and film thickness are combined.
The reflectance for obliquely incident light of 50 ° to 70 ° is reduced by about 4.5 to 6.5%, and the glass surface side having a specified refractive index or a predetermined region of the laminated thin film is satisfied. In the predetermined area where the first thin film of is exposed,
By appropriately covering the laminated thin film, the phenomenon of reflection on the dashboard or these peripheral parts is reduced,
As a combiner for the HUD that enhances the driver's see-through performance, the display and multiple displays that enhance the visibility and visual sensation of various driving information can be displayed, and misidentification or eye fatigue can be prevented to improve safety. At the same time, it is possible to efficiently provide a useful window glass for a vehicle such as a wider choice of dashboard materials and colors.

[Brief description of drawings]

FIG. 1 is a partially enlarged side sectional view of a vehicle window glass according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged side sectional view of a vehicle window glass according to a second embodiment of the present invention.

FIG. 3 is a partially enlarged side sectional view of a vehicle window glass according to a third embodiment of the present invention.

[Explanation of Codes] 1 Window glass for vehicle 3 Inner glass plate 5 First layer thin film 6 Outermost surface layer thin film 7 First layer thin film 8 Second layer thin film 9 Outermost surface layer thin film 10 Combiner for HUD Part 11 laminated thin film

Claims (5)

[Claims] 1. A low-reflection thin film formed on the surface of a glass plate, which is the first thin film from the glass surface in a predetermined region on the low-reflection thin film or among the thin films constituting the low-reflection thin film. At least exposed in a predetermined region, the predetermined region is a thin film having a higher refractive index than the relatively low refractive index of the outermost surface thin film, the entire or partial region of the predetermined region,
A window glass for a vehicle, which is formed by coating at least one laminated thin film. 2. The window glass for a vehicle according to claim 1, wherein the predetermined region in which the low reflection thin film is coated with at least one laminated thin film is formed of a wavelength selective reflection film. 3. A predetermined region where at least the first thin film is exposed from the glass surface of the low reflective thin film is a non-wavelength selective reflective film, and the predetermined region is covered with at least one laminated thin film. 2. The window glass for a vehicle according to claim 1, wherein the whole area or a partial area is made of a wavelength selective reflecting film. 4. The window glass for a vehicle according to claim 1, wherein the low reflection thin film is formed by coating and laminating two or three thin films having different refractive indexes. 5. A window glass for a vehicle according to claim 1, wherein the window glass for a vehicle having the above-mentioned structure is used as a combiner glass for a heads-up display.