JP2000114769A - Electromagnetically shielding glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electromagnetically shielding glass which has not only an electromagnetically shielding performance between 0.1 MHz and 1 GHz but also in a broad range of 1-20 GHz. SOLUTION: The electromagnetically shielding glass is a laminated glass made up of inorganic or organic glasses and a conductive net having a mesh size of 65-150 meshes disposed therebetween, a conductive net having a mesh opening of 10-50 mm is provided parallel thereto and close to a surface of at least one of the glasses or as separated therefrom, and has an electromagnetically shielding performance of 60 dB or more at frequencies of 0.1 MHz-20 GHz.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
In addition to having high electromagnetic shielding performance between Hz, 1
It has excellent electromagnetic shielding performance even up to
The present invention relates to an electromagnetic shielding glass that can also shield (attenuate) electromagnetic waves in mobile phones and PHSs on order.

[0002]

2. Description of the Related Art It is well known that a conductive mesh of about 100 mesh has an excellent electromagnetic shielding performance between 0.1 MHz and 1 GHz, and has been widely used for electromagnetic shielding of various electronic devices. Have been.

Japanese Patent Application Laid-Open No. 6-48284 discloses an electromagnetic shielding plate in which a mesh of conductive wires arranged vertically and horizontally is sandwiched between a pair of transparent plates, and a conductive wire between another pair of transparent plates. An electromagnetic shielding structure is disclosed in which an electromagnetic shielding plate sandwiching a mesh body having an array of conductive wires inclined with respect to the array of conductive wires of the mesh body is arranged in parallel close proximity to each other. When the mesh size is 100 to 150 mesh, the electromagnetic interference performance at 0.1 MHz to 1 GHz is remarkably improved, and the arrangement of both nets is oblique to each other. It is described that can be prevented.

Japanese Patent Application Laid-Open No. 2-302098 discloses that an intermediate layer between an upper layer and a lower transparent plate has a diameter of 80 to 80 mm.
Specified 300 mesh fine mesh conductive net and wire diameter
A transparent electromagnetic wave shielding material having a superposed structure with a coarse mesh conductive net having a mesh of 50 mesh or less or a numerical aperture of 2600 or less / cm ² is disclosed. In addition, it describes that an electromagnetic shielding performance in a magnetic field shield can be exhibited.

In recent years, electronic devices have been diversified, and mobile phones and P
The number of electronic devices using a frequency band of 1 GHz or more, such as HS, is increasing, and the problem that these devices affect other devices as a noise source or are adversely affected is increasing. The above-mentioned known examples do not show particularly excellent electromagnetic shielding performance with respect to the electromagnetic wave of 1 GHz or more.

The present invention has been made in view of the above situation, and has been developed in the range of 0.1 MHz to 1 GHz.
It is an object of the present invention to provide an electromagnetic shielding glass having a wide electromagnetic shielding performance over 1 to 20 GHz as well as an electromagnetic shielding performance in between.

[0007]

According to the present invention, there is provided a laminated glass having a fine conductive mesh having a mesh size of 65 to 150 mesh sandwiched between inorganic or organic glasses, at least one of which is close to or separated from a glass surface. And the eyes open 10-50
This is an electromagnetic shielding glass in which conductive meshes with coarse roughness of mm are juxtaposed, and the electromagnetic shielding performance at a frequency of 0.1 MHz to 20 GHz is -60.
It is an electromagnetic shielding glass of not less than dB.

In the above, it is preferable that the distance between the fine conductive mesh and the coarse conductive mesh is 2 to 300 mm. In addition, in the unit 'dB' indicating the amplification or attenuation rate in the electromagnetic wave, + indicates amplification,-indicates attenuation (shielding side), and the negative value is higher than -60 dB, that is, attenuation (shielding) performance. Is higher.

[0009]

[Embodiment] As described above, the mesh size is 65 to 150.
The conductive mesh of fine mesh (opening of 208 to 104 μm) shows excellent electromagnetic shielding performance at a frequency of 0.1 MHz to 1 GHz, and exhibits a shielding performance of -60 dB or more. In the frequency range of 175 to 125 μm, the frequency exceeds -60 dB in the above frequency range, so that it is frequently used. However, when the frequency exceeds 1 GHz, the shielding performance gradually decreases. According to the tests and examinations of the present inventor, when the fine conductive nets are arranged side by side with the fine conductive nets at intervals, the electromagnetic shielding performance of more than -60 dB over 1 GHz and around 20 GHz is exhibited. I understand.

The distance between the fine and coarse conductive nets is
It is preferably about 2 to 300 mm, and in this range, it exhibits excellent electromagnetic shielding performance with mutual influence and action. On the other hand, if it is in contact with each other or is too close to each other, the electromagnetic shielding effect is more than the above. Tend to be inferior,
If it exceeds 300 mm, not only will the mutual influence and action be weakened, but it will also be uncomfortable because a large space must be taken.
More preferably, it is 3 to 100 mm.

Opening of coarse conductive net (interline spacing)
Is set to 10 to 50 mm, and even if it is less than 10 mm or more than 50 mm, it cannot exhibit a good electromagnetic shielding effect particularly over a frequency of 1 GHz to 20 GHz. It is more preferably 10 to 30 mm. The shape of the mesh is not specified, but it is usually a tortoiseshell (hexagon)
What is easy to form a net, such as a shape, a square, and a rhombus, may be used.

The material of the net is not specified, and a known material such as a copper wire, a steel wire, or a material provided with a blackened oxide film for preventing reflection can be used.

Although the thickness of the wire of both nets is not specified, a wire having an appropriate thickness not to impair the transparency is adopted. The diameter of the wire of the coarse conductive mesh (the band may be a band, in which case the width of the band)
The thickness is set to about 0.2 to 2 mm according to the mesh size.

1A to 1F are side sectional views showing several examples of the form of the electromagnetic shielding glass according to the present invention. FIG.
In A, a fine conductive network 1 is sandwiched between both glass plates 3, 3 via a known interlayer 2, 2, such as ethylene vinyl acetate polymer or polyvinyl butyral, to form a laminated glass 4. A coarse conductive net 5 is attached so as to be in contact with the outer surface of the sash frame 4, and both are fitted into the upper and lower conductive sash frames 6, 6, and the fine conductive net 1 is directly connected to the sash frame. 6 and 6 or a conductive structure such as a conductive structure such as a conductive tape (not shown) disposed on an end surface of the laminated glass 4. The conductive net body 5 is also welded to the sash frames 6 and 6 or is brought into contact with the sash frames 6 and 6 via a conductive sealing material (not shown) to form a conductive structure. The same applies to the example).

The glass may be inorganic glass such as soda-lime-silica glass or organic glass such as polycarbonate.
Various types up to 10 mm or more can be adopted. For example, one glass is made of inorganic glass having a thickness of 5 to 6 mm, the other glass is made of an organic glass having a thickness of 1 mm or less, and a fine conductive mesh is provided between the two in the middle. It may be sandwiched between a film and a transparent adhesive.

FIG. 1B shows that the same laminated glass 4 is fitted in the sash frames 6 and 6 and the coarse conductive net 5 is disposed outside the sash frames, for example, soldered to the outside of the sash frames 6 and 6. FIG. 1C shows a three-layer laminated glass having a central glass 3 and a glass 3 on one side.
A fine conductive net 1 is sandwiched between the glass 3 at the center and the glass 3 'on the other side with a coarse conductive net 5 sandwiched between the central glass 3 and the glass 3' on the other side via an intermediate film. In this example, the integrated three-layer laminated glass 4 ′ is fitted into the sash frames 6, 6.

FIG. 1D shows an example in which the laminated glass 4 and the multi-layered glass 7 having a single-pane glass 3 "interposed therebetween are provided with a coarse conductive net 5 on the inner surface side of the single-pane glass 3". In FIG. 1E, a multi-layered glass 7 'in which two pieces of the laminated glass 4 are arranged via a space is fitted into sash frames 6, 6, and a coarse conductive net 5 is stretched outside the sash frames. For example, FIG. F shows an example of a multiple glass 7 ″ similar to FIG. E, in which a coarse conductive net 5 is added to the surface of one laminated glass 4 on the inner space side.

It is needless to say that various variations of the electromagnetic shielding glass can be obtained by further combining FIGS. 1A to 1F, all of which are within the scope of the present invention.
Of course, fine conductive net, any of coarse conductive net,
Alternatively, if a plurality of both are arranged, the electromagnetic shielding performance is further improved.

FIG. 2 is a front view showing an example of a mesh of a coarse conductive mesh. FIG. 2A is a plan view showing a gap between mesh-shaped meshes (parallel sides).
FIG. 2B shows a wire having a diameter of 15 mm and a wire thickness of 0.91 mmφ, and FIG. 2B shows a wire having a diamond-shaped eye (diagonal line) interval of 20 mm and a wire thickness of 0.45 mmφ. As described above, as for the shape of the mesh, an arbitrary shape, in particular, a shape that is easy to form a net may be adopted.

[0020]

EXAMPLES Example 1 A pair of float glass sheets having a size of 100.times.100 cm and a thickness of 3 mm were used, and an ethylene vinyl acetate polymer (EV
A) and arrange the mesh size between 100 mesh (approx.
150μm), a conductive (copper) mesh with a wire thickness of about 100μm is sandwiched, depressurized and heated by the usual method to cure the interlayer, integrate the glass, and form a laminated glass with a conductive mesh. Was prepared.

On the other hand, as shown in FIG. 2A, a mesh-like mesh was formed, the distance between the eyes (parallel sides) was 15 mm, and the thickness of the wire was 0.2 mm.
A 91 mmφ coarse conductive net (made of steel) was prepared. After winding a commercially available conductive tape around the periphery of the laminated glass, the tape is brought into contact with the sash frame, and the net-sash frame is conducted. As shown in FIG. Fitted in aluminum sash frame 6.

The coarse conductive net 5 was stretched outside the sash frame and fixed to the sash frame by soldering. The distance between the conductive nets 1 and 5 is about 3.5 mm. According to the U.S. mill standard MIL-STD 285, 0.1M
Electromagnetic waves were transmitted over a frequency range from Hz to 20 GHz, and the electromagnetic shielding performance (electromagnetic wave attenuation rate) was measured for horizontal polarization and vertical polarization.

As a result, the average attenuation is about -66 dB from 0.1 MHz to 1 GHz, the average is about -65 dB attenuation from 1 GHz to 20 GHz, and does not fall below -60 dB at any frequency. And good shielding performance.

Incidentally, the electromagnetic shielding performance between frequencies 1 and 2 GHz used in mobile phones and PHSs is as shown in the graphs of FIG. 3 (horizontal polarization plane) and FIG. Yes, showing excellent shielding performance.

[Comparative Example 1] In Example 1, the laminated conductive net was omitted, and only the laminated glass containing the conductive net was used. 1 A similar test was performed.

As a result, the average attenuation was about -63 dB from 0.1 MHz to 1 GHz, but the average attenuation was -40 dB or less from 1 GHz to 20 GHz.

Incidentally, the electromagnetic shielding performance between frequencies 1 and 2 GHz used in mobile phones and PHSs is as shown in the lines of Comparative Example 1 in the graphs of FIG. 3 (horizontal polarization plane) and FIG. 4 (vertical polarization plane). Yes, the average decay rate is -40dB
Or -40 several dB, which is a significant difference from the first embodiment.

Example 2 A laminated glass containing a fine conductive net was produced in the same manner as in Example 1 except that a float plate glass having a thickness of 5 mm was used. On the other hand, the mesh shape shown in FIG.
A coarse conductive net which was opened and had a wire diameter was prepared. As shown in FIG. 1A, with a rough conductive net 5 attached to one surface of the laminated glass 4, both are fitted into an aluminum sash frame 6. The inner conductive net 1 was electrically connected to the sash frame 6 by soldering a conductive tape wound around the periphery of the laminated glass, and the coarse conductive net 5 was soldered to a sash frame. The distance between the conductive nets 1 and 5 is about 5 mm.

The same test as in Example 1 was carried out.
Shows an average attenuation of about -65 dB from 1 MHz to 1 GHz,
At ~ 20 GHz, the average attenuation is about -63 dB.
It does not fall below -60dB at any frequency,
It showed good shielding performance.

[0030]

According to the present invention, not only the electromagnetic shielding performance between 0.1 MHz and 1 GHz but also the excellent electromagnetic shielding performance over a wide range from 1 GHz to 20 GHz can be exhibited.

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[Procedure amendment]

[Submission date] November 24, 1998 (1998.11.
24)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Added

[Correction contents]

[Brief description of the drawings]

1A to 1F are side sectional views showing some examples of the form of an electromagnetic shielding glass according to the present invention.

FIGS. 2A and 2B are front views showing examples of a coarse conductive mesh.

FIG. 3 is a graph showing the electromagnetic shielding performance between 1 and 2 GHz on the horizontal plane of polarization, and the vertical axis indicates the electromagnetic shielding performance (−).
dB), and the horizontal axis indicates frequency (GHz).

FIG. 4 is a graph showing the electromagnetic shielding performance between 1 and 2 GHz in the vertical polarization plane, and the vertical axis represents the electromagnetic shielding performance (−).
dB), and the horizontal axis indicates frequency (GHz).

[Description of Signs] 1 Fine conductive net 2 Interlayer 3 Glass plate 4 Laminated glass 5 Coarse conductive net 6 Conductive sash frame 7, 7 ', 7 "Multi-glass

Claims (2)

[Claims] 1. A laminated glass in which a fine conductive mesh having a mesh size of 65 to 150 mesh is sandwiched between inorganic or organic glasses, is close to or separated from at least one glass surface, and an opening of the mesh is 10 or less. An electromagnetic shielding glass in which a coarse conductive net of up to 50 mm is juxtaposed, wherein the electromagnetic shielding performance at a frequency of 0.1 MHz to 20 GHz is -60 dB or more. 2. The electromagnetic shielding glass according to claim 1, wherein the distance between the fine conductive net and the coarse conductive net is 2 to 300 mm.