WO2003045126A1

WO2003045126A1 - Electromagnetic wave shielding light transmitting window material and method for producing the same

Info

Publication number: WO2003045126A1
Application number: PCT/JP2002/011545
Authority: WO
Inventors: Hidefumi Kotsubo; Yasuhiro Morimura; Itsuo Tanuma
Original assignee: Bridgestone Corporation
Priority date: 2001-11-20
Filing date: 2002-11-06
Publication date: 2003-05-30
Also published as: AU2002365993A1; JPWO2003045126A1

Abstract

In order to produce an electromagnetic wave shielding light transmitting window material having a conductive pattern of small line width and a high opening ratio, a metal foil (3) is bonded onto a transparent film (1) using an adhesive (2). A resist is then printed in a lattice form onto the metal foil (3) thus forming a resist pattern (4). Thereafter, the metal foil (3) not covered with the resist pattern (4) is removed by etching.

Description

Description: EMI shielding light transmitting window material and method for producing the same

The present invention relates to an electromagnetic wave shielding light transmitting window material useful as a front filter of a plasma display panel (PDP), a window material of a building requiring an electromagnetic wave shield such as a hospital (for example, a sticking film), and a method of manufacturing the same. In particular, the present invention relates to an electromagnetic wave shielding light transmitting window material formed by forming a conductive pattern on a film and a method for producing the same. Background of the Invention

In order to shield electromagnetic waves generated from equipment such as office automation equipment and communication equipment, window materials that have electromagnetic wave shielding properties and are light transmissive have been developed as front filters for equipment. This window material is also used as a window material in places where precision equipment is installed, such as hospitals and laboratories, in order to protect precision equipment from electromagnetic waves such as mobile phones.

A conventional electromagnetic wave shielding light transmitting window material has a pair of transparent substrates such as an acrylic plate, and a conductive mesh or a transparent conductive film such as a wire mesh interposed between the transparent substrates. These are integrated.

The conductive mesh used for the conventional electromagnetic shielding light transmitting window material is generally about 5 to 500 mesh with a wire diameter of 10 to 500 μm, and the aperture ratio is 75%. Is less than. The aperture ratio is calculated from the line width of the mesh and the number of lines existing in one inch width. In the conventional electromagnetic shielding light transmitting window material using the conductive mesh, the light transmittance is at most about 70%.

In a conventional conductive mesh, moire (interference fringes) is likely to occur in relation to the pixel pitch of a light emitting panel to which an electromagnetic wave shielding light transmitting window material is attached.

By using a transparent conductive film instead of a mesh, it is conceivable to achieve both light transmittance and electromagnetic shielding properties.However, the transparent conductive film is not compatible with the housing. It is not easy to achieve conduction.

The periphery of the conductive mesh protrudes from the periphery of the transparent substrate, and the periphery is bent, and the periphery is electrically connected to the housing. If the edge of the transparent conductive film protrudes from the edge of the transparent substrate and is bent, the film will tear at the fold.

An object of the present invention is to provide an electromagnetic wave shielding light transmitting window material having a conductive pattern having a sufficiently small line width and an extremely high aperture ratio, and a method for manufacturing the same. According to the method for producing an electromagnetic wave shielding light transmitting window material of the present invention, an electromagnetic wave shielding light transmitting window material having a conductive pattern formed of metal on a surface of a transparent film is produced. The method includes the steps of: bonding a metal foil to the surface of the transparent film; forming a resist pattern having the same pattern as the conductive pattern on the surface of the metal foil; Removing the metal foil not covered by the resist pattern to form the conductive pattern.

This resist for forming a resist pattern has a low viscosity, and a fine and precise resist pattern is formed. The conductive pattern formed under the resist pattern has a significantly smaller line width and therefore a larger aperture ratio.

According to the present invention, for example, an electromagnetic wave shielding light transmitting window material having a conductive pattern having a line width of 200 m or less and an aperture ratio of 75% or more can be manufactured.

The electromagnetic wave shielding light transmitting window material of the present invention is manufactured by the method of the present invention. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1, 2, 3, 4 and 5 are cross-sectional views illustrating an example of the method of the present invention. Detailed description

In the example of the present invention shown in FIGS. 1 and 2, an adhesive 2 is used on a transparent film 1. And the metal foil 3 is bonded. Next, as shown in FIG. 3, a resist is printed in a grid pattern on the metal foil 3 to form a resist pattern 4. Next, as shown in FIG. 4, the etching process is performed, and the metal foil 3 not covered with the resist pattern 4 is removed. Then, as shown in FIG. 5, the resist pattern 4 is removed.

The above etching process removes only the portion of the metal foil 3 that is not covered with the resist pattern 4, and the metal foil 3 below the resist pattern 4 remains without being etched and is made of metal. The conductive pattern becomes 3 A. The adhesive 2 may remain on the transparent film 1 without being removed if it is transparent. By this etching, the adhesive 2 may be removed together with the metal foil 3, the adhesive 2 may be removed by using a solvent after the etching, and the adhesive 2 may be removed together with the removal of the resist pattern 4. Alternatively, the adhesive 2 may be removed after the removal of the resist pattern 4.

Since the conductive pattern 3A is formed below the lattice-shaped resist pattern 4, it has the same lattice shape as the resist pattern 4. By reducing the line width of the resist pattern 4, a lattice-shaped conductive pattern 3A having a small line width is formed. By reducing the line width of the grid-like resist pattern 4 and increasing the area of the opening of the resist pattern 4, a grid-like conductive pattern 3A having a large aperture ratio is formed.

In the present invention, the resist pattern 4 is not removed, and the processing may be stopped in the state of FIG. 4 to provide an electromagnetic wave shielding light transmitting window material. By doing so, the conductive pattern 3A becomes an electromagnetic wave shielding light transmitting window material covered with the resist. This resist has an antireflection function. When the blackening process described later is performed, the resist is removed. Next, preferred examples of each of the above materials will be described.

As a material of the transparent film 1, a transparent synthetic resin which is not eroded by an etching solution is used. Examples of this synthetic resin include polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyarylate, polycarbonate, polymethyl methacrylate, and triacetate. Hardness is preferred. The thickness of the transparent film 1 is preferably about 50 to 300 μπι in order to provide rigidity to the electromagnetic wave shielding light transmitting window material to facilitate handling.

As the metal foil 3, metals or alloys such as aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, and zinc are preferable, and among these, copper is preferable. Pure metals or alloys of aluminum, nickel, chromium, zinc, tin, silver or gold are preferred.

The thickness of the metal foil 3 is preferably about 0.1 to 20 μπι. If the thickness is less than 0.1 μππι, electromagnetic wave shielding performance will be insufficient. If the pattern 3 厚 is thicker than 20 μπι, the viewing angle of the electromagnetic wave shielding light transmitting window material will be narrowed, and the etching will also spread in the width direction. Α may not be formed.

As the adhesive 2 for bonding the metal foil 3 to the transparent film 1, a general-purpose and highly transparent material such as an epoxy-based, urethane-based, or acrylic-based adhesive can be used. The layer thickness of the adhesive 2 may be about 5 to 50 μπι.

The resist pattern 4 formed on the metal foil 3 is preferably formed by printing. As the printing material, those commercially available as a photo resist or the like are preferable, and among them, a solution containing an acrylic polymer as a main component is preferable. When a pattern is printed using a photo resist, an etching process is performed after curing by irradiating energy rays such as ultraviolet rays.

The resist pattern 4 is preferably printed so as to form a lattice. Preferably, the line width is printed so as to be not more than 200 μm, particularly preferably not more than 100 μm, especially not more than 30 μm. Daravia printing, screen printing, flexo printing, and offset printing are suitable as printing methods, but gravure printing is preferable for thinning.

The printing thickness of the resist pattern 4 is not particularly limited, but is usually about 0:! To 10 µm.

The etching solution is selected depending on the material of the metal foil 3. It is sufficient to use various types of etching liquid itself. For example, metal foil is copper, iron, anoremi, nickel, For chromium, zinc, tin, etc., a ferric chloride solution can be used. After the formation of the conductive pattern 3A, a blackening treatment may be performed to impart antiglare properties. In addition, a metal foil previously blackened may be bonded to the transparent film 1. As a method of blackening, it is possible to adopt oxidation treatment of a metal film, black plating treatment of a chromium alloy or the like.

The electromagnetic wave shielding light transmitting window material manufactured in this manner may be composed of a single film, or may be a continuous web-like film unwound from a roll. Example

Hereinafter, an example will be described, but this example is an example of the present invention, and the present invention is not limited thereto.

Example 1

On a polyethylene terephthalate film having a thickness of 100 μm, a blackened copper foil having a thickness of 12 m was bonded with a two-component curing epoxy adhesive (layer thickness: 20 μπι). On this, a UV-curable resist ink (PHOTOEDP-500, manufactured by Nippon Paint) was printed in a grid pattern, and then cured by UV irradiation. The lattice was regularly arranged in the form of a square lattice. The line width of the lattice was 20 μm, one side of the lattice was 250 μm, and the aperture ratio was 80%. The print thickness is about 2 μm after UV curing. Next, an etching treatment was performed using a ferric chloride-based etchant. After that, the resist pattern was removed using an aqueous sodium hydroxide solution (3%) as a resist remover to obtain an electromagnetic wave shielding light transmitting window material. The adhesive (the part of the adhesive not covered by the conductive pattern 3A) remained on the film without being removed. The conductive pattern on the surface of this film is regularly arranged in a square lattice, and, like the resist pattern, the line width is 20 μππ, one side of the lattice is 250 μππι, and the aperture ratio is 80%.

As described above, an electromagnetically shielded light transmitting window material having a conductive pattern with a small line width and a high aperture ratio is manufactured.

Claims

The scope of the claims

1. A method for producing an electromagnetic shielding light-transmitting window material in which a conductive pattern made of metal is formed on a surface of a transparent film,

Bonding a metal foil to the surface of the transparent film,

Forming a resist pattern having the same pattern as the conductive pattern on the surface of the metal foil;

Then, an etching process is performed to remove the metal foil not covered by the resist pattern to form the conductive pattern.

2. The method according to claim 1, wherein the resist pattern is formed in a lattice pattern.

3. The method according to claim 1, wherein the resist pattern is formed by printing.

4. The method for producing an electromagnetic wave shielding light transmitting window material according to claim 1, wherein after forming the conductive pattern, the conductive pattern is blackened.

5. The transparent film according to any one of claims 1 to 4, wherein the transparent film is selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polycarbonate, polymethyl methacrylate, polyarylate and triacetate. A method for producing an electromagnetic-shielding light-transmitting window material, comprising at least one kind.

6. The method according to claim 5, wherein the transparent film has a thickness of 50 to 300 μπι.

7. The electromagnetic wave according to any one of claims 1 to 6, wherein the metal foil is a metal foil made of at least one of copper, aluminum, nickel, chromium, zinc, tin, silver, and gold. A method for manufacturing a light-transmitting window material having a shielding property.

8. The method according to any one of claims 1 to 7, wherein the thickness of the metal foil is 0. Method for producing wave-shielding light-transmitting window material. A method for producing an electromagnetic wave shielding light-transmitting window material, which has a thickness of 1 to 20 μm.

9. The method for manufacturing an electromagnetic wave shielding light transmitting window material according to any one of claims 1 to 8, wherein the resist for forming the resist pattern is mainly composed of acryl polymer. .

10. The method of manufacturing an electromagnetic wave shielding light transmitting window material according to any one of claims 1 to 9, wherein the metal foil is adhered with an adhesive.

11. The electromagnetic shield according to any one of claims 1 to 10, wherein the conductive pattern has a line width of 200 μππ or less and an aperture ratio of 75% or more. Of producing a transparent light transmitting window material.

12. An electromagnetic wave shielding light transmitting window material manufactured by the method according to any one of claims 1 to 11.