JPH09148781A - Filter for preventing leakage of electromagnetic wave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress electromagnetic wave leaking from a plasma display panel without having any effect on the image. SOLUTION: The filter 2 for preventing leakage of electromagnetic wave is fixed to the front face of a plasma display panel 1 such that a conductive mesh is arranged on the plasma display panel 1 side and the conductive mesh is grounded through a ground piece 3. In the filter 2 for preventing leakage of electromagnetic wave, the conductive mesh comprising longitudinal and lateral mesh wires crossing perpendicularly is provided on one side of a transparent resin plate while inclining at an angle of about 45 deg. against the horizontal axis thereof. Density of the mesh is set at about 100 lines/inch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for preventing electromagnetic wave leakage, and more particularly to a filter suitable for suppressing electromagnetic waves leaking from the display surface of a plasma display panel.

[0002]

2. Description of the Related Art Plasma display panels (hereinafter,
"PDP") is being used in various display devices because of its thin depth and light weight.
The light emission of this PDP uses plasma discharge, so that unnecessary electromagnetic waves are leaked to the outside. Its frequency components span the band from about 30 to 130 MHz. Therefore, it is necessary to suppress electromagnetic wave leakage as much as possible so as not to interfere with other devices (for example, information processing devices). Conventionally, as a method of suppressing the electromagnetic wave leakage, for example, a metal film 42 having a thickness of about 0.2 μm is formed on the surface of a transparent acrylic plate 41 as shown in FIG.
Attached to the PDP display surface by vapor deposition (ITO treatment), or, as shown in FIG. 2B, a transparent acrylic plate having a conductive mesh 43 made of metal or the like provided on one surface thereof as shown in the figure. The leakage of electromagnetic waves to the outside has been suppressed by grounding the metal film or the conductive mesh.

[0003]

However, the method using a metal film [FIG. 4 (A)] cannot obtain a sufficient suppressing effect because the thickness thereof is as thin as about 0.2 μm. [FIG. 4 (B)], although the suppression effect is high, there is an adverse effect of lowering the brightness and sharpness of the image. Further, since the method using a metal film uses an acrylic plate, interference between the acrylic plate and the PDP display surface may cause optical Newton rings (bright and dark ring zones), which may make the image uncomfortable. there were. As described above, the suppression effect is not sufficient in the conventional method, or
It was affecting the image. The present invention has been made under such a background, and without affecting the image,
Moreover, it is an object of the present invention to provide an electromagnetic wave leakage prevention filter having a large suppression effect.

[0004]

According to the present invention, there is provided a conductive resin mesh on one surface of a transparent resin plate, wherein conductive meshes are formed such that mesh lines in the vertical direction and the mesh lines in the horizontal direction are orthogonal to each other. A filter for preventing electromagnetic wave leakage, comprising the conductive mesh on the transparent resin plate such that an angle formed by a horizontal mesh line and a horizontal axis of the transparent resin plate is a predetermined acute angle, Is attached to the front surface of the display surface of the plasma display panel so that the conductive mesh is on the side of the plasma display panel, and the conductive mesh is grounded via a grounding piece to suppress electromagnetic waves leaking from the display surface of the plasma display panel. A filter for preventing electromagnetic wave leakage is provided.

[0005]

The electromagnetic wave leaked from the PDP is shielded by the grounded conductive mesh. In addition, the conductive mesh is PD
The inclination of P with respect to the horizontal scanning direction allows the image to be displayed without lowering the brightness or the like.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetic wave leakage prevention filter according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a state in which an electromagnetic wave leakage prevention filter according to the present invention is attached to a PDP, FIG. 2 is a conceptual view of the structure of the electromagnetic wave leakage prevention filter according to the present invention, and FIG. 3 is a partially enlarged view of FIG. In FIG. 1, 1 is a PDP (plasma display panel), 2 is an electromagnetic wave leakage prevention filter according to the present invention, 3 is a grounding piece for grounding a conductive mesh, and 4 and 5 are casings of this apparatus. The electromagnetic wave leakage prevention filter 2 according to the present invention is
The PDP display device 1 is attached and used as shown in FIG. In this case, the conductive mesh side described below is the PDP display surface side, and the conductive mesh is grounded via the grounding piece.

A conceptual diagram of the structure of the electromagnetic wave leakage prevention filter 2 is shown in FIG. As shown in the figure, a conductive mesh 22 made of metal or the like is provided on one surface of a transparent resin plate (for example, an acrylic plate) 21. As a material of the conductive mesh 22, for example, a material obtained by subjecting a base material such as polyester to electroless plating of copper or nickel has been already put into practical use. Further, there are various mesh wires having a diameter of about 30 to 60 μm. The conductive mesh 22 is provided at a predetermined acute angle θ with respect to the transparent resin plate 21 as shown in FIG. In addition,
The vertical mesh lines 23 and the horizontal mesh lines 24 that form the mesh are orthogonal (90 degrees). When the filter is attached to the PDP by providing the angle θ shown in the figure (Fig. 1)
It is possible to prevent a decrease in the brightness and sharpness of the image. This is P
This is because the horizontal scanning line and the mesh line in the DP display do not overlap each other. From the above, when the angle θ is around 45 degrees, the decrease in brightness and the like is minimized.

There is a mesh density as another component of this mesh, and there is a method of expressing the mesh density by using the number of meshes per unit length. For example, there is a method of expressing by the number of meshes per inch, and this expression is used in this specification. This mesh density affects both the image and the electromagnetic wave leakage suppression effect. That is, if the mesh is too coarse, the decrease in brightness and the like will decrease, but the electromagnetic wave leakage prevention effect will decrease, and if the mesh is too subdivided, the electromagnetic wave leakage prevention effect will increase, but brightness will decrease. Therefore, the mesh density is about 1 as a decrease in brightness and the effect of preventing electromagnetic wave leakage.
It is suitable to set it to around 00 (lines / inch).

On the other hand, in the filter according to the present invention, a transparent resin plate such as an acrylic plate is used. However, when such a transparent resin plate is provided in front of the PDP display surface, it causes an optical Newton ring. sell. This Newton's ring becomes remarkable when the resin plate and the PDP display surface are in close contact with each other. Therefore, face-to-face contact must be avoided. On the other hand, in this filter, as shown in the enlarged view of FIG. 3, since the conductive mesh 22 is provided on the transparent resin plate 21, the presence of the mesh inherently causes the transparent resin plate 1
It is avoided that the PDP and the PDP come into close contact with each other. Therefore, when used for a long time, the resin plate 21 is heated due to the temperature rise on the surface of the PDP, and even if the resin plate 21 warps on the PDP 1 side, the existence of the conductive mesh 22 prevents surface contact.
Further, since this conductive mesh is grounded via the grounding piece 3 as shown in FIG. 1, it is possible to prevent the above-mentioned face-to-face contact from this grounding structure as well, and thus prevent the generation of Newton's rings. The ground piece 3 is at ground potential (ground potential) via the screw 6. In the grounding by the grounding piece 3, in order to reduce the contact resistance between the same-mesh mesh 22 and the grounding piece 3, a conductive adhesive may be used on the contact surfaces of both to bond them. It is also effective to use a resilient grounding piece such as a grounding spring as the grounding piece 3 in order to reduce the contact resistance.

[0010]

As described above, according to the present invention, the mesh density is about 1 on one surface of a transparent resin plate such as an acrylic plate.
Since a conductive mesh of 00 metal or the like was applied, and the method of applying the conductive mesh was such that the line in the lateral direction of the mesh and the horizontal axis of the transparent resin plate were about 45 degrees, this filter was used. By attaching the conductive mesh to the display surface of the PDP and grounding the conductive mesh, it is possible to suppress electromagnetic waves leaking from the PDP without causing adverse effects such as reduction in image brightness. As a result, about 30 to 300 MHz
The PDP electromagnetic wave leakage that leaks in the band is suppressed, interference with other devices can be prevented, and deterioration of the display image is prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a filter according to the present invention for preventing electromagnetic wave leakage as a PD.
It is a side view of the state attached to P.

FIG. 2 is a perspective view showing a structural concept of an electromagnetic wave leakage prevention filter according to the present invention.

FIG. 3 is a partially enlarged side view of an electromagnetic wave leakage prevention filter attached state in FIG.

FIG. 4A and FIG. 4B are perspective views showing a structural concept of a conventional electromagnetic wave leakage prevention filter.

[Explanation of symbols]

 1 Plasma display panel (PDP) 2 Electromagnetic wave leakage prevention filter 3 Grounding piece 4 Housing 21 Transparent resin plate 22 Conductive mesh 23 Vertical mesh line 24 Horizontal mesh line

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroomi Otsu 1116 Suenaga, Takatsu-ku, Kawasaki City Inside Fujitsu General Limited

Claims (5)

[Claims] 1. A transparent resin plate, wherein a conductive mesh is formed on one surface of a transparent resin plate in which vertical and horizontal mesh lines are formed so as to be orthogonal to each other. An electromagnetic wave leakage prevention filter, characterized in that the conductive mesh is provided on the transparent resin plate such that an angle formed by the horizontal axis of the transparent resin plate is a predetermined acute angle. 2. The electromagnetic wave leakage prevention filter according to claim 1, wherein the predetermined acute angle is about 45 degrees. 3. The electromagnetic wave leakage prevention filter according to claim 1, wherein the conductive mesh of the electromagnetic wave leakage prevention filter has a mesh density of about 100 meshes per inch. 4. The electromagnetic wave leakage prevention filter is attached to the front surface of the display surface of the plasma display panel so that the conductive mesh is on the plasma display panel side, and the conductive mesh is grounded via a grounding piece. The electromagnetic wave leakage prevention filter according to claim 1, wherein the filter is provided for suppressing electromagnetic waves leaking from the panel display surface. 5. The electromagnetic wave leakage prevention filter is attached to the front surface of the display surface of the plasma display panel so that the conductive mesh is on the plasma display panel side, and the conductive mesh and the ground piece are bonded with a conductive adhesive. The electromagnetic wave leakage prevention filter according to claim 1, wherein the filter is grounded through the grounding piece to suppress electromagnetic waves leaking from the display surface of the plasma display panel.