JPS6081047A - Window glass for electromagnetic shielding - Google Patents

Abstract

PURPOSE:To shield electromagnetic waves and to inhibit the penetration of infrared rays by laminating an electrically conductive transparent thin film for electromagnetic shielding and a heat rays reflecting film on the outside of a glass substrate and an electrically conductive transparent thin film for electromagnetic shielding and a film for preventing the reflection of visible light on the inside. CONSTITUTION:An electrically conductive transparent thin film 2 for electromagnetic shielding such as an ITO film made of a solid soln. consisting of In2O3 and SnO2 and a heat rays reflecting film 3 are laminated on the outside of a glass substrate 1 to be exposed to the air for a car window or the like. An electrically conductive transparent thin film 2 made of the same material as the film 2 and a film 4 for preventing the reflection of visible light are laminated on the inside of the substrate 1 to manufacture window glass for electromagnetic shielding. The film 3 is formed by alternately laminating TiO2 layers 3a and SiO2 layers 3b. The film 4 is made of SiO2 or the like. When this window glass is used, a noise due to extraneous electric waves can be controlled, the penetration of solar radiation can be inhibited, and the field of clear vision can be ensured.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an electromagnetic shielding window glass.

The electromagnetic shielding window glass of the present invention can be used as a window glass for vehicles, aircraft, and buildings. for example,
When the electromagnetic shielding windshield of the present invention is used in an automobile window glass, it is possible to prevent noise (EMI: electromagnetic interference) caused by external radio waves from being caused to in-vehicle electronic devices, and it is also possible to suppress the intrusion of solar radiation into the vehicle interior. This is useful for ensuring good visibility, preventing noise, and preventing increases in vehicle interior temperature.

[Prior art]

In automobiles, external radio waves enter through the windshield. This external radio wave may become noise to in-vehicle electronic equipment. Conventionally, in order to prevent such EMI, measures have been taken for EMI resistance among in-vehicle electronic devices, but no measures have been taken for the window glass itself. Therefore, the number of electronic components for EMI countermeasures increased, causing an increase in costs.

Furthermore, the temperature inside the vehicle increases due to solar radiation, and the ineffectiveness of the air conditioner causes great discomfort when riding, especially in the summer or when parking during the day. Conventionally, as a countermeasure against this problem, a heat ray reflecting film that reflects wavelengths in the infrared region, which has little effect on daylighting, has been provided on the windshield of a car, but it has not been said to be sufficient.

In addition, due to the diversification of user preferences, the number of meters has increased,
Along with this, the number of lighting devices and luminous intensity at night are increasing. As a result, a reflected image may be created on the front windshield or side window glass, obstructing the driver's field of vision. Although these problems can be addressed by installing a rheostand (a device that freely controls the illuminance of meters and instrument panels when driving at night) or by devising the shape of the meter hood and panel, the fundamental It has not been resolved.

Therefore, it has been desired to solve the above problem with the window glass itself.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art described above, and aims to provide an electromagnetic shielding window glass that can shield electromagnetic waves, significantly inhibit the intrusion of infrared rays, and prevent reflections on the glass. .

[Structure of the invention]

According to the present invention, a transparent conductive thin film for electromagnetic shielding and a heat ray reflective film are laminated in this order on the outer surface of the glass substrate when in use, while an electromagnetic shielding film is laminated on the inner surface of the glass substrate when in use. This is achieved by an electromagnetic shielding window glass characterized in that a transparent conductive thin film for use with visible light and an anti-reflection film for visible light are laminated in this order.

As previously mentioned, the electromagnetic shielding window glass of the present invention has a transparent conductive thin film for electromagnetic shielding and a heat ray reflective film laminated on the outside of a glass substrate, and a transparent conductive thin film for electromagnetic shielding and a visible light antireflection film on the inside. It is characterized by the fact that it has been set up.

In the present invention, commonly used tempered glass, partially tempered glass, laminated glass, etc. can be used as the glass substrate.

As a material for the transparent conductive thin film, for example, ITO (a solid solution of indium oxide (In20i) and tin dioxide (Sn02)) can be used. Since the electromagnetic shielding window glass of the present invention needs to be transparent, the thickness of the transparent conductive thin film is set in the range of 100 to several microns so that electromagnetic waves in the visible wavelength range are transmitted. Note that the thickness of the transparent conductive thin film does not directly affect the structure of the heat ray reflective film, so it can be determined as appropriate within the above range.

Therefore, it is possible to increase the film thickness for the purpose of improving the electromagnetic shielding effect and the infrared absorption effect of the transparent conductive thin film.

Note that the transparent conductive thin film can also be used as one of the optical thin films constituting a heat ray reflective film or a visible light antireflection film.

Further, it is desirable that the surface resistance (sheet resistance) of the transparent conductive thin film for electromagnetic shielding is several hundreds of ohms or less.

The transparent conductive thin film may be directly grounded by a supporting member such as a conductive adhesive, a spacer, a dam, or a clip that contacts the window glass, or may be grounded by high frequency through capacitive coupling.

In the present invention, a conventionally known optical thin film is used as the heat ray reflective film. An optical thin film is a thin film formed on the surface of a substrate such as glass for the purpose of preventing reflection, increasing reflection, etc. on the substrate surface, and utilizes the interference effect of light. An optical thin film may be formed of only one layer, but it may also be formed as a so-called multilayer film in which high refractive index materials and low refractive index materials are alternately laminated. As high refractive index substances, zirconium oxide (zro2), titanium oxide (T i O□), etc. are used, and as low refractive index substances, silicon dioxide (Sin), magnesium fluoride (M
g F 2 ) etc. are used.

Optical ml! When @ is formed as a multilayer film, the antireflection effect and the reflection increasing effect can be further enhanced. Furthermore, it is possible to widen the wavelength range of light that causes reflection prevention or increased reflection, and increase the degree of freedom in selecting the material forming the thin film in relation to its refractive index.

In the present invention, for example, TiO2 is used as the heat ray reflective film.
A multilayer film in which a film and a 5i02 film are laminated can be used. At this time, the film thickness of each optical thin film in the heat ray reflective film is λ/4 (λ: wavelength of infrared rays to be reflected) in optical film thickness. However, the thickness of the top layer of the heat ray reflective film is λ
/8.

In the present invention, the visible light antireflection film may be made of, for example, cerium fluoride (CeF), zirconium oxide (Z
r02) and magnesium fluoride (Mg Ot ) can be used. In addition, silicon dioxide (SiO
The optical thin film of 2) may be a single layer, or a transparent conductive thin film and a silicon dioxide optical thin film may be laminated. These optical thin films are laminated in the above order from the inner surface of the glass substrate toward the inside of the vehicle. The thickness of these optical thin films is 0.0
5μ to 0.3μ is desirable.

The above-mentioned transparent conductive thin film, heat ray reflective film, and visible light antireflection film are formed on a glass substrate or the like by an appropriate surface treatment technique such as a vacuum coating method, sputtering, or ion blasting.

[Action of the invention]

Infrared rays incident from the outside world cause phase interference in the heat ray reflective film, and are suppressed from entering the vehicle interior, resulting in most (50%)
degree) is reflected back to the outside world. The remaining infrared rays are absorbed (approximately 20 to 30% of the incident infrared rays) while passing through the electromagnetic shielding transparent conductive thin film, and a total of 70 to 80% of the infrared rays are prevented from entering the vehicle interior.

On the other hand, radio waves incident from the outside world are electromagnetically shielded by the transparent conductive thin film, and high-frequency current induced in the transparent conductive thin film flows to the podium via the grounding section, preventing radio waves from entering the vehicle interior.

Furthermore, the anti-reflection film for visible light greatly suppresses reflection of visible light, reducing reflections on the glass.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

(a) In the electromagnetic shielding window glass of the present invention, the heat ray blocking rate is improved by 20 to 30% as a whole, since the transparent conductive thin film acts to absorb heat rays, compared to when only a heat ray reflective film is used.

(b) According to the present invention, it is possible to simultaneously prevent the intrusion of external radio waves, the intrusion of infrared rays, and the reflection on the glass with one glass, and it is very effective and practical in terms of cost performance.

(c) Since the transparent conductive thin film is provided on both sides of the glass substrate, the electromagnetic shielding effect is large.

(d) The heat ray reflective film and the visible light antireflection film are excellent in durability because they serve as protective films for the transparent conductive thin film.

(E) Costs for EMI resistance of electronic devices can be reduced, and the cooling performance of air conditioners can be improved.

(f) The purpose of use of the window glass is to be multi-functional.
Product appeal improves.

(g) Since sputtering can be performed simultaneously on the same surface, labor savings in production can be achieved.

(H) The thickness of the transparent conductive thin film for electromagnetic shielding can be set arbitrarily, and the optimal thickness can be selected depending on the purpose and necessity.

〔Example〕

Next, preferred embodiments of the present invention will be described with reference to the drawings.

(First Example) Fig. 1 is a perspective view showing an automobile to which the electromagnetic shielding window glass of the present invention is applied, Fig. 2 is a cross-sectional view taken along - I11 is a partially enlarged view.

In FIG. 1, the electromagnetic shielding window glass of the present invention is attached to the hunting area &Ii.

In FIG. 2, 1 is a glass substrate, and a transparent conductive thin film is formed on the outer surface of the glass substrate 1.
A film 2 is provided, and a heat ray reflective film 3 is further provided on 1TO1jJ2.
is provided. On the other hand, an ITO film 2 and a visible light anti-reflection film 4 are provided on the inner surface of the glass substrate 1. The electromagnetic shielding window glass 5 of the present invention is formed by the glass substrate 1, the 11'0 film 2, the heat ray reflective film 3, and the visible light antireflection film 4. The electromagnetic shielding window glass 5 is
It is fixed between the window frame 6 and the molding 7 with a conductive adhesive 8. In addition, 9 is a dam that prevents the conductive adhesive 8 from protruding, and 10 is an electromagnetic shielding window glass 5 and a window frame 6.
This is a spacer that fills the gap and prevents the electromagnetic shielding window glass 5 from shifting downward.

The ITO film 2 is grounded to the body (window frame 5) with a conductive adhesive 8.

As shown in a partially enlarged view in FIG. 3, the heat ray reflecting film 3 is composed of six layers of optical thin films. This optical thin film is made of titanium oxide (T i 02), which is a high refractive index material.
3 a and silicon dioxide (SiO2) 3 which is a low refractive index substance
b are used and are laminated alternately.

Titanium oxide optical thin film 3a and silicon dioxide optical film 1
The optical film thickness nd (n is the refractive index, d is the film thickness) of %3b is 1/4 of the wavelength of the infrared rays to be reflected. Also,
The optical thickness nd of the silicon dioxide optical thin film 3b forming the uppermost layer is 178 times the wavelength of the infrared rays.

For example, if the wavelength of the infrared rays to be reflected is set to about 11050n, the refractive index of titanium oxide corresponding to this wavelength is about 2.3, and the refractive index of silicon dioxide is about 1.45, so in this case, the oxidized Film thickness of titanium optical thin film 3a: 1
The thickness of the optical thin film 3b of silicon dioxide is 18
Approximately 10 people 8, the top layer silicon dioxide optical thin film 3b
Only about 900 people will be 8.

The thickness of the ITO film 2 can be set arbitrarily, but in this example, the outer ITO film 2a is one of the optical thin films constituting the antireflection film 4, so the film thickness is approximately 680 λ/8.
The inner ITO film 2b is a visible light anti-reflection film 4.
Irrespective of this, the film thickness was set at 5,000 people.

Furthermore, as an antireflection film 4 for visible light, an optical thin film 4a of silicon dioxide was provided. At this time, the wavelength of visible light to be prevented from being reflected was set to 520 nm, and the thickness of the optical thin film 4a of silicon dioxide was approximately 900 nm.

The ITO film 2, the heat ray reflective film 3, and the visible light antireflection film 4 were formed on the glass substrate 1 and the ITO film 2, respectively, by RF magnetron sputtering.

After sputtering, heat treatment was performed at 350° C. for 90 minutes.

The electromagnetic shielding window glass obtained as a result has an infrared reflectance of 50% due to the heat ray reflection film and an infrared absorption rate of 25% due to the TTO film, so a total of 7 infrared rays
5% were blocked. Therefore, it was possible to maintain coolness in the vehicle interior and reduce the load on the air conditioner.

Further, the electromagnetic shielding window glass of this example is r'ro
The electromagnetic shielding effect was improved by 10 to 20 dB compared to the conventional one without a film.

Furthermore, in a conventional window glass without an anti-reflection film for visible light, the reflectance for visible light was 4.5% both inside and outside, but in the electromagnetic shielding window glass of this example, the reflectance for visible light was 1.0% on the outside. %, and 2.5% on the inner side, significantly preventing reflection. Therefore, the reflection on the glass was reduced.

(Second Embodiment) FIG. 4 is a schematic diagram of an electromagnetic shielding window glass showing a second embodiment.

The difference between the second embodiment and the first embodiment is that the film thickness of the ITO film is opposite to that of the first embodiment;
This is substantially the same as the example.

The electromagnetic shielding window glass of the second embodiment has the same infrared shielding effect and electromagnetic shielding effect as the first embodiment, but the reflectance of visible light is opposite inside and outside. Therefore, the reflection of indoor lighting etc. on the glass is more reduced in the second embodiment.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. For example, a single layer film of magnesium fluoride and aluminum oxide (Al2O,) or a three-layer film of cerium fluoride, zirconium oxide, and magnesium fluoride can be used as an antireflection film for visible light.

It should be noted that since electronic devices are concentrated in the front of a car, the electromagnetic shielding effect can be quite effective simply by providing it on the windshield glass of the car.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an automobile to which the electromagnetic shielding windshield of the present invention is applied, Fig. 2 is a sectional view taken along nn of Fig. FIG. 4 is a schematic diagram of an electromagnetic shielding window glass according to a second embodiment of the present invention. 1 - Glass substrate 2 - - Transparent conductive thin film (ITO film) 2 a - Outer transparent conductive thin film 2 b - Inner transparent conductive thin film 3 - Heat ray reflective film 3 a --Titanium monoxide film (optical thin film) 3b--
-Silicon dioxide 191i (optical thin film) 4-1~--Visible light antireflection film 4a---Silicon dioxide film (optical thin film) 5-111 Electromagnetic shielding window glass 6---Window frame 7- ----- Molding 8 ----- Conductive adhesive 9 ----- Dam 10 ----- Spacer Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A transparent conductive thin film for electromagnetic shielding and a heat ray reflective film are laminated in this order on the outer surface of the glass substrate when in use, while a transparent conductive thin film for electromagnetic shielding is laminated on the inner surface of the glass substrate when in use. An electromagnetic shielding window glass characterized by having a transparent conductive thin film and a visible light antireflection film laminated in this order. (2. In claim 1, the transparent conductive thin film for electromagnetic shielding is made of ITO (indium Mide).
An electromagnetic shielding window glass characterized in that it is a solid solution of In203) and tin dioxide (SnO2). (3) The electromagnetic shielding window glass according to claim 1, wherein the heat ray reflective film is a laminate of titanium oxide and silicon dioxide. (4) The electromagnetic shielding window glass according to claim 1, wherein the visible light antireflection film is made of a silicon dioxide film.