JP2008049975A - Window glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly restrain the slit antenna effect of window glass. <P>SOLUTION: This window glass 10 is formed by forming a transparent conductive layer 2 having transparency and electric conductivity on a transparent base board 1. Electric resistance of the transparent conductive layer 2 increases toward a central part 10a from an end side part 10b of the glass 10. The thickness of the transparent conductive layer 2 may be reduced toward the central part 10a from the end side part 10b of the glass 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a window glass in which a transparent conductive layer having transparency and conductivity is formed on a transparent substrate, for example.

Conventionally, an electromagnetic wave shielding glass in which two transparent substrates are bonded with an adhesive layer and a conductive layer is formed between the two transparent substrates is known (for example, see Patent Document 1). The electromagnetic wave shielding glass shields an electromagnetic wave having a specific frequency by this conductive layer.
JP 2001-185894 A

  2. Description of the Related Art Conventionally, in a frame of a vehicle body that is a conductor, a frame portion on which a window glass for a vehicle that is an insulator is provided becomes a slit, and a so-called slit antenna is formed. In addition, due to the slit antenna, external radio waves from outside the passenger compartment may resonate at a frequency corresponding to the size of the slit (the length in the lateral direction of the window glass). Due to this resonance, for example, the electric field strength of the external radio wave increases several times (slit antenna effect), so that an electronic device mounted on the vehicle may be adversely affected by noise or the like due to the electric field of the external radio wave.

  On the other hand, in the conventional electromagnetic wave shielding glass, since the electromagnetic wave shielding conductive layer is formed on the entire surface of the glass, the slit antenna effect can be suppressed. For example, a radio wave from a mobile phone is necessary. There is a possibility that radio waves cannot be received in the vehicle, which is inconvenient for the user.

  The present invention is for solving such a problem, and a main object thereof is to appropriately suppress the slit antenna effect of window glass.

In order to achieve the above object, one embodiment of the present invention provides:
A glass for windows in which a transparent conductive layer having transparency and conductivity is formed on a transparent substrate,
The window glass is characterized in that the electrical resistance of the transparent conductive layer increases as it goes from the edge to the center of the glass.

  According to this one aspect, the electrical resistance of the transparent conductive layer increases as it goes from the edge of the glass to the center. Thereby, a slit antenna effect can be controlled appropriately.

  In this aspect, the thickness of the transparent conductive layer may be decreased from the edge of the glass toward the center. Thereby, it is possible to increase the electric resistance of the transparent conductive layer with a simple configuration as it goes from the edge portion to the center portion of the glass.

  In this embodiment, the transparent conductive layer may be composed so that the electrical resistance of the transparent conductive layer increases as it goes from the edge to the center of the glass. Thereby, it is possible to increase the electric resistance of the transparent conductive layer with a simple configuration as it goes from the edge portion to the center portion of the glass.

  In this aspect, the transparent conductive layer may be insulative in the vicinity of the central portion of the glass, and the conductivity may be increased toward the end side portion. Thereby, since a required radio wave can be transmitted in the vicinity of the central portion that is insulative, the user can reliably receive the required radio wave in the passenger compartment. Furthermore, the conductivity increases as it goes to the edge (the electric resistance of the transparent conductive layer gradually increases from the edge to the center), so that the electromagnetic energy is concentrated on the slit edge. Therefore, the slit antenna effect can be suppressed. That is, the slit antenna effect of the window glass can be appropriately suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the slit antenna effect of the glass for windows can be suppressed appropriately.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  A window glass 10 according to an embodiment of the present invention is disposed, for example, on a front window 11 disposed on a front side of a vehicle cabin, a rear window 12 disposed on a rear side, and on a side side. Applied to the side window 13 (FIG. 1).

  FIG. 1 is a view showing a state in which a window glass 10 according to an embodiment of the present invention is applied to a front window 11 (FIG. 2).

  The window glass 10 has a transparent and conductive transparent conductive layer 2 formed between two transparent glass plates (transparent substrates) 1, and the glass plates 1 and the transparent conductive layer 2 are bonded to each other. They are integrated (FIG. 3).

  For example, the glass plate 1 is obtained by chemically or thermally strengthening silicate glass that is usually used as glass for automobiles. The thickness of each glass plate 1 is, for example, about 3 to 5 mm. If the glass plate 1 is too thin, the penetration resistance is reduced. If the glass plate 1 is too thick, the transparency is reduced.

  For example, a conductive adhesive resin film as an adhesive layer is used between the two glass plates 1 for the transparent conductive layer 2. This conductive adhesive resin film is provided with conductivity and has an electromagnetic wave shielding property for shielding electromagnetic waves.

  The conductive adhesive resin film is formed by mixing conductive particles together with various additives in an adhesive resin such as PVB resin and EVA resin, thereby providing the above-mentioned conductivity.

  Examples of the conductive particles include (1) carbon particles or powder, (2) metals such as nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, aluminum, copper, titanium, cobalt, lead, etc. Or alloys or particles or powders of these conductive oxides, and (3) those obtained by forming a coating layer of the conductive material (1) or (2) above on the surface of plastic particles such as polystyrene or polystyrene. It is.

  Moreover, since the particle size of electroconductive particle will influence the light transmittance and the thickness of an adhesive resin film when it is too large, it is preferable that it is 0.5 mm or less, and about 0.01-0.5 mm. More preferred.

  Furthermore, if the mixing ratio of the conductive particles is excessively large, the light transmittance is impaired, whereas if it is excessively small, the electromagnetic wave shielding property is insufficient. For this reason, it is preferable to set it as 0.1 to 50 weight% by weight ratio with respect to adhesive resin (for example, EVA resin), and it is more preferable to set it as 0.1 to 20 weight%.

  In addition, although the color and glossiness of electroconductive particle are suitably selected as desired, for the windshield 11, for example, in order to maintain a high light transmittance, a color tone such as blue is preferable.

  By the way, the case where the slit antenna which consists of a slit (slot) of length L and width W is formed in conductors (conductor plate), such as a metal, is assumed. Due to the external radio wave reaching the conductor of the slit antenna, a high-frequency current having a resonance frequency corresponding to the length L of the slit flows to the slit edge (surrounding), and electromagnetic energy concentrates on the slit edge. For this reason, the high frequency current is re-radiated from the slit edge into the slit. This re-radiation of the high-frequency current greatly increases the electric field strength in the external radio wave having the resonance frequency that has passed through the slit (slit antenna effect).

  Similarly to the above, in the frame of the vehicle body that is a conductor, the frame portion where the front window 11 of the vehicle is provided becomes a slit, and the slit antenna is formed in the vehicle. For example, when an external radio wave arrives from the front of the vehicle, the electric field strength of the external radio wave having a resonance frequency corresponding to the length of the front window in the lateral direction is increased by passing through a slit antenna conventionally formed in the vehicle. Increase (solid line shown in FIG. 4).

  Therefore, in the window glass 10 according to the present embodiment, the thickness of the transparent conductive layer 2 is formed so as to gradually increase from the end portion 10b of the window glass 10 to the center portion 10a. (Figure 3). Thereby, the said slit antenna effect can be suppressed.

  In addition, since electrical conductivity becomes high as the thickness of the transparent conductive layer 2 increases, the electrical resistance value of the transparent conductive layer 2 decreases. Therefore, as described above, the thickness of the transparent conductive layer 2 is gradually increased from the end portion 10b of the window glass 10 toward the central portion 10a, so that the electric resistance value of the transparent conductive layer 2 is reduced to the window. The glass 10 can be simply configured so as to gradually increase from the end 10b to the center 10a. In this case, the electromagnetic wave shielding property of the transparent conductive layer 2 gradually decreases as it goes from the end portion 10b of the window glass 10 to the central portion 10a.

  The transparent conductive layer 2 as described above has both good electromagnetic shielding properties and light transmittance when the thickness of the layer 2 is in the range of 0.2 to 0.4 mm, for example. That is, when the thickness of the transparent conductive layer 2 is less than 0.2 mm, the electromagnetic wave shielding property is lost and the electromagnetic wave is transmitted. On the other hand, when the thickness of the transparent conductive layer 2 exceeds 0.4 mm, the light transmittance may be impaired.

  Therefore, in the vicinity of the central portion 10a of the window glass 10, the thickness of the transparent conductive layer 2 is, for example, approximately 0 mm, which is an insulator. This makes it possible to transmit necessary electromagnetic waves in the vicinity of the central portion 10a of the window glass 10. On the other hand, the thickness of the transparent conductive layer 2 gradually increases from the central portion 10a of the window glass 10 toward the end portion 10b, and is, for example, about 0.4 mm in the vicinity of the end portion 10b. . Thereby, the transparency of the edge part 10b of the glass 10 for windows is ensured, and a slit antenna effect can be suppressed reliably.

  FIG. 4 is a diagram showing an example of the relationship between the electric field strength (V / m) and the frequency (MHz) in the instrument panel in the vehicle interior when the front window 11 is irradiated with radio waves from the front of the vehicle. It is the figure which compared the glass 10 for windows which concerns on, and the conventional glass for windows. In addition, the dotted line of FIG. 4 has shown an example of the relationship between the electric field strength and the frequency in the glass 10 for windows which concerns on a present Example. Moreover, the continuous line of FIG. 4 has shown an example of the relationship between the electric field strength and frequency in the conventional window glass.

  As shown by the solid line in FIG. 4, in the window glass 10 according to the present embodiment, the slit antenna effect is suppressed, so that there is no resonance at a specific frequency. Therefore, the electric field strength is a good value that is kept low at any frequency.

  On the other hand, as shown by the broken line in FIG. 4, in the conventional window glass, the slit antenna effect is greatly generated, so that resonance occurs at a specific frequency. Therefore, the electric field strength greatly increases at this specific frequency, which may cause noise in electronic devices in the passenger compartment, for example.

  Although the case where the window glass 10 is applied to the front window 11 of the vehicle has been described as described above, the case where the window glass 10 is applied to the rear window 12 or the side window 13 of the vehicle is also abbreviated as the case of the front window 11. Since it becomes the same structure, an effect | action, and an effect, detailed description is abbreviate | omitted.

  As described above, in the window glass 10 according to the present embodiment, the thickness of the transparent conductive layer 2 is formed so as to gradually decrease from the end portion 10b of the window glass 10 to the center portion 10a. Thereby, the electrical resistance value of the transparent conductive layer 2 gradually increases from the end 10b of the window glass 10 toward the center 10a, and the vicinity of the center 10a becomes an insulator. Thereby, the electromagnetic wave energy caused by the external radio wave reaching the window glass 10 can be dispersed on the window glass 10 and can be reduced from being concentrated on the slit edge. For this reason, the slit antenna effect of the glass 10 for windows can be suppressed. In addition, since the influence of the noise with respect to the electronic device in a vehicle can be reduced by suppressing a slit antenna effect, the special EMC countermeasure is unnecessary.

  Further, in the vicinity of the center portion 10a of the window glass 10, the transparent conductive layer 2 is an insulator. Therefore, necessary radio waves from a mobile phone or the like can pass through the vicinity of the central portion 10a of the window glass 10. Therefore, since the user can reliably transmit and receive necessary radio waves in the vehicle interior, user convenience is ensured. That is, the slit antenna effect of the window glass 10 can be appropriately suppressed.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  In the above embodiment, the thickness of the transparent conductive layer 2 is formed so as to gradually decrease from the edge portion 10b of the window glass 10 to the center portion 10a. You may be comprised so that it may change gradually as it goes to the center part from the edge part of the glass for windows. For example, the transparent conductive layer may be composed so that the electrical resistance value of the transparent conductive layer gradually increases from the edge of the window glass toward the center. More specifically, as the electrical resistance value of the transparent conductive layer gradually increases from the edge portion of the window glass to the center portion, the electric resistance value of the transparent conductive layer increases from the edge portion of the window glass to the center portion. The density of the conductive particles in the transparent conductive layer may be gradually decreased.

  In the above embodiment, the conductive adhesive resin film as the transparent conductive layer 2 is formed between the two glass plates 1, but the conductive film is interposed between the two glass plates via the adhesive resin film. May be sandwiched. Moreover, the structure by which the transparent conductive layer 2 is formed on the glass plate 1 of 1 sheet may be sufficient. That is, any configuration is applicable as long as the transparent conductive layer 2 is formed on the glass plate 1.

  In the above embodiment, one glass plate 1 of the two glass plates 1 is formed with the same thickness, but as it goes from the end portion 10b of the window glass 10 to the central portion 10a, the glass plate 1 becomes transparent. A configuration in which the thicknesses of both glass plates 1 increase while the thickness of the conductive layer gradually decreases may be employed. That is, any configuration can be applied as long as the thickness of the transparent conductive layer gradually decreases from the edge portion 10b of the window glass 10 toward the center portion 10a.

  In the above embodiment, the window glass 10 is applied to each window disposed in the passenger compartment of the automobile, but is not limited thereto, and each window disposed in a moving body such as a train, a ship, and an aircraft. It is applicable to.

  INDUSTRIAL APPLICABILITY The present invention can be used for window glass used in a vehicle front window, a rear window, and a side window.

It is a figure which shows an example of the state by which the window glass which concerns on one Example of this invention was arrange | positioned in the compartment of the motor vehicle. It is a figure which shows an example of the structure by which the glass for windows which concerns on one Example of this invention was applied to the front window of a vehicle. It is a fragmentary sectional view which shows the principal part of the glass for windows which concerns on one Example of this invention. It is a figure which shows an example of the relationship between an electric field strength and a frequency, and is the figure which compared the glass for windows which concerns on a present Example, and the conventional glass for windows.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass plate 2 Transparent conductive layer 10 Window glass 10a Center part 10b Edge part 11 Front window

Claims (4)

A glass for windows in which a transparent conductive layer having transparency and conductivity is formed on a transparent substrate,
The window glass according to claim 1, wherein the electrical resistance of the transparent conductive layer increases from the edge of the glass toward the center. The window glass according to claim 1,
The thickness of the said transparent conductive layer reduces as it goes to the center part from the edge part of the said glass, The glass for windows characterized by the above-mentioned. The window glass according to claim 1,
The window glass according to claim 1, wherein the transparent conductive layer is composed so that the electric resistance of the transparent conductive layer increases from the edge to the center of the glass. The window glass according to any one of claims 1 to 3,
The window glass, wherein the transparent conductive layer is insulative in the vicinity of the central portion of the glass, and the conductivity is increased toward the end side portion.