JPH1126984A - Electromagnetic wave shield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shield which is excellent not only in electromagnetic wave shielding but also in transparency, and is suitably used for an electromagnetic wave shielding filter or the like of an image display device. SOLUTION: An electromagnetic wave shield is formed on a surface of a transparent resin base material, in which a conductive portion made of a conductive fine powder and a binder resin and formed by a line drawing a pattern composed of many squares or circles of the same shape is formed. Wherein the width of the line constituting the conductive portion is 5 to 25 μm, and the pattern pitch is 50 to 2000 μm.
m electromagnetic wave shield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shield, and more particularly, to an electromagnetic wave shield having excellent electromagnetic wave shielding properties, excellent transparency, and suitably used for an electromagnetic wave shielding filter of an image display device.

[0002]

2. Description of the Related Art Conventionally, as a method of shielding electromagnetic waves, a method of attaching an aluminum foil or a copper foil to a plastic film, a method of forming a thin film of tin-doped indium oxide, antimony-doped tin oxide, silver or the like have been known. ing. However, these methods are not used as an electromagnetic wave shielding filter of an image display device because of lack of transparency or insufficient transparency.

[0003] On the other hand, in order to obtain good transparency and electromagnetic wave shielding properties, a method of depositing a conductive metal on a transparent substrate and etching it to form a mesh, a method of attaching a conductive fiber, and the like are also available. Are known. However, these methods have economical problems and are not transparent enough to satisfy market requirements.

Japanese Patent Application Laid-Open Nos. Sho 62-57297 and Hei 3-53594 disclose electromagnetic waves by printing a conductive paint or the like on a transparent substrate in a grid-like or stripe-like or honeycomb-like pattern. Although a method of providing transparency together with shielding is disclosed, the line width of these patterns is 100
It is about μm, and still does not have sufficient transparency so that it can be used as an electromagnetic wave shielding filter of an image display device.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art relating to an electromagnetic wave shield, and therefore, the present invention has excellent electromagnetic wave shielding properties and excellent transparency. It is an object of the present invention to provide an electromagnetic wave shield suitably used for an electromagnetic wave shield filter or the like of an image display device.

[0006]

According to the present invention, there is provided a conductive resin comprising a conductive resin powder and a binder resin formed on a surface of a transparent resin base material by drawing a plurality of square or circular patterns having the same shape. An electromagnetic wave shield having a portion formed thereon, wherein the width of a line forming the conductive portion is 5 to 25 μm and the pattern pitch is 50 to 2000 μm.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The resin used for the transparent resin substrate in the present invention includes, for example, a saturated polyester resin, a polycarbonate resin, a poly (meth) acrylate resin, an alicyclic polyolefin resin, and polystyrene. Resin, polyvinyl chloride resin, polyvinyl acetate resin and the like.

The transparent resin substrate in the present invention can be formed into a film by a known method such as a method of melt-molding these resins by extrusion molding, calender molding, compression molding, injection molding, or the like, or a method of dissolving in a solvent and casting. It is formed into a shape or a sheet, and its thickness is from 10 μm
It is about 5 mm. In addition, these transparent resin base materials may contain additives generally used, for example, phenol-based, phosphorus-based antioxidants, halogen-based, phosphorus-based flame retardants, heat stabilizers, ultraviolet absorbers, lubricants, and the like. , An antistatic agent and the like may be added.

In the present invention, the conductive portion formed on the surface of the transparent resin substrate is made of a conductive fine powder and a binder resin. Here, as the conductive fine powder, gold, silver,
A simple metal such as platinum, palladium, nickel, copper, and aluminum, and a carbon material such as carbon black and graphite are used.
It is about 01 to 10 μm.

As the binder resin, an acrylic resin, a polyester resin, a polyvinyl chloride resin or the like is used. In addition, the content of the conductive fine powder in the conductive portion is 75 to the total amount with the binder resin.
It is about 95% by weight.

In the present invention, the conductive portion formed on the surface of the transparent resin substrate is constituted by a line drawing a pattern consisting of a number of squares or circles of the same shape. Here, the pattern consisting of a large number of squares or circles of the same shape is a triangle,
Or, each of the squares such as squares, rectangles, rhombuses, etc. may be adjacently drawn in a lattice shape, for example, each of the turtle-shaped squares may be drawn adjacently,
In addition, various squares or circles may be independently drawn.

What is important in the present invention is that the width of a line constituting the conductive portion by the pattern is 5 to 25 μm and the pitch of the pattern is 50 to 2000 μm. If the line width is less than 5 μm or the pattern pitch exceeds 2000 μm, a sufficient electromagnetic wave shielding effect cannot be obtained, and the line width is 2 μm.
If it exceeds 5 μm or the pattern pitch is less than 50 μm, the transparency will be insufficient. In addition, the height of these lines is 2 to
It is preferably 15 μm from the viewpoint of electromagnetic wave shielding.

In the present invention, a typical printing technique is used to form the conductive portion on the surface of the transparent resin substrate. In order to obtain a stable line width and pattern pitch, especially screen printing is used. Is preferred. For screen printing, for example, 75 to 95% by weight of the conductive fine powder, 25 to 5% by weight of the binder resin, and 100 to 100 parts by weight thereof, 3 to 65% by weight of a solvent such as toluene, xylene, methyl ethyl ketone, or cyclohexanone. Parts, and dispersants 1 to 1 such as anionic and nonionic surfactants
From 10 parts by weight, a conductive ink having a viscosity of 1,000 to 100,000 cps, preferably about 3,000 to 20,000 cps is prepared, and the screen is formed using a screen having a resist coating obtained by printing a pattern such as the square of the line width and the pattern pitch. Printing can be performed by a conventionally known method of printing on the surface of a transparent resin substrate.

At this time, prior to printing, the surface of the transparent resin substrate may be subjected to a known surface treatment such as a corona discharge treatment, a plasma discharge treatment, a flame treatment, a chemical treatment, and a primer treatment.

[0015] In the electromagnetic wave shield of the present invention, it is preferable that a protective film is laminated on the conductive portion formed on the surface of the transparent resin substrate. Resins are used, and the resins are laminated by a known method such as dry lamination, wet ramie, extrusion lamination, and the like.

A flat panel display such as a CRT, an electroluminescence display (ELD), a plasma display (PDP), and a liquid crystal display (LCD) is further provided with a near-infrared absorption layer, an antireflection layer, an anti-scratch layer and the like. And the like, and is suitably used for an electromagnetic wave shielding filter of an image display device.

[0017]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. Example 1 Polyethylene terephthalate resin film (thickness 100
μm) is screen printed with a DuPont special gold ink containing fine gold powder using a 500-mesh stainless steel wire mesh (opening 25 μm) screen with a PDP screen printer (Microtech). In this way, a conductive part in which a square pattern was drawn in a grid pattern with a line width of 15 μm, a pattern pitch of 1000 μm, and a line height of 5 μm was formed, and an electromagnetic wave shield was manufactured.

With respect to the obtained electromagnetic wave shielding body, the electromagnetic wave shielding property and the transparency were evaluated, and the results are shown in Table 1. In addition, the electromagnetic wave shielding property measures the attenuation (dB) in the frequency range of 30 to 500 MHz, and the transparency is such that the standing electromagnetic wave shielding body is visually observed at a distance of 1 m and the pattern cannot be confirmed. 、, when it could be confirmed was evaluated as ×.

Example 2 A silver ink made by Jujo Kako (“JELC”) containing silver fine powder
OM SH-1 "), the conductive portion in which a square pattern was drawn had a line width of 20 μm, a pattern pitch of 1000 μm, a line height of 3 μm, and a 100 μm thick polyethylene terephthalate film on the conductive portion. Except that the protective film was laminated, an electromagnetic wave shielding body was manufactured in the same manner as in Example 1, and the electromagnetic wave shielding property and the transparency were measured. The results are shown in Table 1.

Comparative Example 1 An electromagnetic wave shield was manufactured in the same manner as in Example 1, except that the line width of the conductive portion in which the square pattern was drawn was 100 μm and the pattern pitch was about 6670 μm. The measurement was performed and the results are shown in Table 1.

[0021]

[Table 1]

[0022]

According to the present invention, it is possible to provide an electromagnetic wave shield having excellent electromagnetic wave shielding properties and excellent transparency, and which is suitably used for an electromagnetic wave shielding filter of an image display device.

Claims (6)

[Claims] 1. An electromagnetic wave shield comprising a transparent resin substrate and a conductive portion formed of a plurality of lines each having a shape of a plurality of squares or circles of the same shape and formed of conductive fine powder and a binder resin on a surface of the transparent resin substrate. The width of a line constituting the conductive portion is 5 to 25 μm, and the pitch of the pattern is 50 to 2000 μm.
m. 2. A conductive part comprising a line drawing a pattern,
The electromagnetic wave shield according to claim 1, which is formed by printing. 3. The electromagnetic wave shield according to claim 2, wherein the printing is by screen printing. 4. A conductive part comprising a line drawing a pattern,
2. The image display device according to claim 1, wherein the display device is formed in a grid shape depicting a square.
4. The electromagnetic wave shield according to any one of claims 1 to 3. 5. The electromagnetic wave shield according to claim 1, wherein the conductive fine powder is at least one selected from the group consisting of gold, silver, platinum, palladium, and nickel. 6. The electromagnetic wave shield according to claim 1, wherein a protective film is laminated on a conductive portion formed by a pattern-drawn line.