JP2001332889A - Method for manufacturing electromagnetic wave shielding light transmitting window material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture an electromagnetic wave shielding light transmitting window material having a mesh-like conductive pattern with less line width and high numerical aperture. SOLUTION: Firstly, as shown in (1) and (2), dots 2 are printed on a transparent film 1 using a material soluble in a solvent such as water. Then, as shown in (3), a conductive material layer 3 is formed so as to cover all exposed surfaces of the film 1 on the dot 2 as well as between dots 2. The film 1 is washed in a solvent such as water. Thus, as shown in (4), the soluble dot 2 dissolves and the conductive material on the dot 2 is also released from the film 1 and removed. A conductive pattern 4 comprising the conductive material formed in the region between the dots is formed on the film 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding light transmission useful as a front filter of a plasma display panel (PDP) or a window material (for example, a sticking film) of a building requiring an electromagnetic wave shield such as a hospital. The present invention relates to a method for manufacturing a window material, and more particularly to a method for manufacturing an electromagnetic wave shielding light transmitting window material having a conductive pattern formed on a film.

[0002]

2. Description of the Related Art In recent years, with the spread of office automation equipment and communication equipment, electromagnetic waves generated from these equipment have become a problem. That is, there is a concern that the electromagnetic waves may affect the human body, and malfunctions of precision equipment due to the electromagnetic waves have become a problem.

Therefore, as a front filter of a PDP of an OA device, a window material having an electromagnetic wave shielding property and a light transmitting property has been conventionally developed and put to practical use. Such a window material is also used as a window material in a place where precision equipment is installed, such as a hospital or a laboratory, in order to protect precision equipment from electromagnetic waves such as mobile phones.

[0004] The conventional electromagnetic wave shielding light transmitting window material has a structure in which a conductive mesh material such as a wire mesh or a transparent conductive film is interposed between transparent substrates such as an acrylic plate to be integrated. I have.

The conductive mesh used for the conventional electromagnetic shielding light transmitting window material generally has a wire diameter of 10 to 500.
It is about 5 to 500 mesh in μm, and the aperture ratio is less than 75%.

[0006] In the conventional conductive mesh, generally, the conductive fiber constituting the mesh has a large wire diameter, the coarser the mesh, and the thinner the wire, the finer the mesh.
This is because it is possible to form a coarse mesh with fibers having a large wire diameter, but it is very difficult to form a coarse mesh with fibers having a small wire diameter.

For this reason, in the conventional electromagnetic wave shielding light transmitting window material using such a conductive mesh, even a material having a good light transmittance is at most about 70%, and it is possible to obtain a good light transmittance. There was a disadvantage that it could not be done.

Further, in the conventional conductive mesh, there is a problem that moire (interference fringes) is easily generated in relation to the pixel pitch of the light emitting panel on which the electromagnetic wave shielding light transmitting window material is mounted.

It is conceivable that both light transmittance and electromagnetic wave shielding properties can be achieved by using a transparent conductive film in combination. However, the transparent conductive film has a drawback that it is not easy to establish conduction with the housing. is there.

That is, in the case of a conductive mesh, as described above, the periphery of the conductive mesh protrudes from the periphery of the transparent substrate, the protruding portion is bent, and conduction from the bent portion to the housing is achieved. However, in the case of a transparent conductive film, if the peripheral portion of the transparent conductive film protrudes from the peripheral portion of the transparent substrate and is bent, the film is torn at the fold portion and conduction with the housing cannot be achieved.

It is also conceivable to form a transparent conductive film directly on the bonding surface of one transparent substrate instead of the transparent conductive film. In this case, the transparent conductive film is formed on the other transparent substrate. Therefore, conduction from the transparent conductive film to the housing cannot be achieved.

Therefore, when a transparent conductive film is used, it is necessary to make a design change such as forming a through hole in a transparent substrate to provide a conduction path with the transparent conductive film. The work of assembling the window material and assembling it into the housing becomes complicated.

In order to solve such problems and prevent the moire phenomenon, an electromagnetic wave shielding light transmitting window material having extremely excellent light transmittance, electromagnetic wave shielding property, and heat ray (near infrared ray) cutting property is provided. In addition, a method is proposed in which a conductive ink is printed in a grid pattern with a line width of 200 μm or less and an aperture ratio of 75% or more on the surface of a transparent plate in a pattern.

In such an electromagnetic-shielding light-transmitting window material, a conductive layer having a desired pattern shape can be formed by pattern printing. It is much larger than
Even a grid-shaped conductive layer having a fine line with a line width of 200 μm or less and an aperture ratio of 75% or more and a high aperture ratio can be easily formed. In addition, a conductive print film having such a fine line and a coarse conductive layer formed thereon can obtain good light transmittance and prevent a moire phenomenon.

The aperture ratio is calculated from the mesh line width and the number of lines existing in one inch width.

[0016]

As the above-mentioned conductive ink, one obtained by dispersing conductive fine particles in a binder (ink medium) is used. In order to maintain the ink, the viscosity of the ink needs to be sufficiently high. For this reason, the ink line width could not be significantly reduced, and the aperture ratio could not be significantly increased.

An object of the present invention is to provide a method for producing an electromagnetic wave shielding light transmitting window material having a mesh-like conductive layer having a sufficiently small line width and an extremely high aperture ratio.

[0018]

According to the present invention, there is provided a method for producing an electromagnetic wave shielding light transmitting window material, wherein dots are formed on a film surface by using a substance soluble in a solvent, and a dot is formed on the film surface with respect to the solvent. A conductive material layer made of an insoluble conductive material, and contacting the film surface with the solvent to remove the dots and the conductive material layer on the dots.

According to the method of manufacturing the electromagnetic wave shielding light transmitting window material, the conductive fine particles are not dispersed in the material soluble in the solvent, and the dots can be printed and formed with a low-viscosity material. . For this reason, fine and minute printing can be performed so as to significantly reduce the interval between dots. Since the narrow region between the dots is a region where the conductive material later remains and becomes a mesh-shaped conductive layer, according to the present invention, a significantly thin conductive mesh pattern can be formed with high accuracy. it can. By reducing the line width, the aperture ratio of the mesh can be increased.

According to the method of the present invention, for example, an aperture ratio of 75%
An electromagnetic shielding light transmitting window material having the above conductive mesh pattern can be easily manufactured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an example of the present invention.
First, dots 2 are printed on a transparent film 1 using a material soluble in a solvent such as water as described above. Then
As described above, the conductive material layer 3 is formed so as to cover the entire exposed surface of the film 1 on the dots 2 and between the dots 2. Next, the film 1 is washed with a solvent such as water. At this time, if necessary, ultrasonic irradiation, brush,
A dissolution promoting means such as rubbing with a sponge or the like may be used in combination.

As a result, as shown in FIG.
Is dissolved, and the conductive material on the dots 2 is also peeled off from the film 1 and removed. Then, the conductive pattern 4 made of the conductive material formed in the region between the dots remains on the film 1. Since the conductive pattern 4 occupies the area between the dots 1, it has a mesh shape as a whole.

Therefore, the mesh-shaped conductive pattern 4 having a small line width is formed by reducing the gap between the dots 2. Also, by increasing the area of each dot 2, a mesh-shaped conductive pattern 4 having a large aperture ratio is formed. The printing material soluble in water or the like for forming the dots 2 does not need to disperse the fine particles, and a low-viscosity material is sufficient. With this low-viscosity printing material, dots can be printed in a fine dot pattern.

After the above-described steps, the substrate is subjected to finish washing (rinsing) if necessary, and dried to obtain an electromagnetic wave shielding light transmitting window material.

Next, preferred examples of each of the above materials will be described.

As the transparent film 1, polyester,
Polyethylene terephthalate (PET), polybutylene terephthalate, polymethyl methacrylate (PMM
A), acrylic plate, polycarbonate (PC), polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion-crosslinked ethylene-methacrylic acid copolymer , Polyurethane, cellophane, etc., preferably PE
T, PC, and PMMA.

The thickness of the transparent film varies depending on the application of the electromagnetic wave shielding light transmitting window material and the like, but is usually about 1 μm to 5 mm.

The dots formed on the film 1 are preferably formed by printing. As a printing material, a solution of a material that is soluble in a solvent that removes dots is used. As a solvent for removing the dots, an organic solvent may be used, but water is preferable because it is inexpensive and has an adverse effect on the environment. Water is normal water, acid,
It may be an aqueous solution containing an alkali or a surfactant. The printing material may be mixed with a pigment or a dye in order to make it easier to confirm the printing condition.

In view of the fact that the solvent is water,
As the dot forming material, a water-soluble polymer material is preferable, and specifically, polyvinyl alcohol and the like are suitable.

The dots 2 are printed such that the film exposed area between them is meshed. Preferably,
Printing is performed so that the line width of the exposed film area is 30 μm or less. As a printing method, gravure printing, screen printing, inkjet printing, and electrostatic printing are preferable, but gravure printing is preferable for thinning.

The nature of the dot is a mystery such as a circle, an ellipse, and a square, but is preferably a square, especially a square.

The printing thickness of the dots is not particularly limited, but is usually about 0.1 to 5 μm.

After printing the dots, they are preferably dried, and then the conductive material layer 3 is formed. As this material, a metal or alloy such as aluminum, nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, copper, titanium, cobalt, lead or a conductive oxide such as ITO is preferable.

If the thickness of the conductive material layer 3 is too small, the electromagnetic wave shielding performance will be insufficient, which is not preferable. If the thickness is too large, the thickness of the obtained electromagnetic wave shielding light transmitting window material is affected, and the viewing angle is reduced. Because it narrows,
The thickness is preferably about 0.5 to 100 μm.

The conductive material layer 3 may be formed by a vapor phase plating method such as sputtering, ion plating, vacuum deposition, or chemical vapor deposition, liquid phase plating (electrolytic plating, electroless plating, etc.), printing, coating, and the like. Examples include vapor phase plating in a broad sense (sputtering, ion plating,
Vacuum vapor deposition, chemical vapor deposition) or liquid phase plating are preferred.

After the formation of the conductive material layer 3, as described above,
The dots 2 are removed using a solvent, preferably water, and dried as necessary to obtain an electromagnetic wave shielding light transmitting window material.

The electromagnetic wave shielding light transmitting window material may be formed of a single film or a continuous web film unwound from a roll.

[0039]

The present invention will be described more specifically with reference to the following examples.

Example 1 A 20% aqueous solution of polyvinyl alcohol was printed in dot form on a polyethylene film having a thickness of 500 μm.
Each dot has a square shape with one side of 234 μm, the interval between the dots is 20 μm, and the dot arrangement is a square lattice. The printing thickness is about 5 μm after drying.

On top of this, aluminum is coated with an average film thickness of 10 μm.
m was vacuum deposited. Next, it was immersed in water at room temperature and rubbed with a sponge to dissolve and remove the dot portion, then rinsed with water and dried to obtain an electromagnetic wave shielding light transmitting window material.

The conductive layer on the surface of the film is a square lattice that exactly corresponds to the negative pattern of dots.
The line width was 20 μm and the aperture ratio was 77%. The average thickness of the conductive layer (aluminum layer) was 10 μm.

[0043]

As described above, according to the present invention, an electromagnetic wave shielding light transmitting window material having a mesh-shaped conductive pattern having a small line width and a high aperture ratio can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a method for manufacturing an electromagnetic wave shielding light transmitting window material according to an embodiment.

[Explanation of symbols]

 Reference Signs List 1 film 2 dot 3 conductive material layer 4 conductive pattern

Claims (8)

[Claims] 1. A dot is formed on a film surface with a substance soluble in a solvent, a conductive material layer made of a conductive material insoluble in the solvent is formed on the film surface, and the film surface is A method for producing an electromagnetic wave shielding light transmitting window material, comprising removing the dots and a conductive material layer on the dots by contacting with a solvent. 2. The method according to claim 1, wherein the solvent is water. 3. The method according to claim 2, wherein the substance soluble in the solvent is a water-soluble polymer material. 4. The method according to claim 3, wherein the water-soluble polymer material is polyvinyl alcohol. 5. The method according to claim 1, wherein the dots are formed by printing. 5. The method according to claim 1, wherein the dots are formed by printing. 6. The method according to claim 1, wherein the conductive material layer is formed by vapor phase plating or liquid phase plating. 7. The method according to claim 1, wherein the conductive material layer is formed by coating. 8. The method according to claim 1, wherein the dots and the conductive material layer on the dots are removed to form a grid-like conductive material pattern having an aperture ratio of 75% or more. A method for producing an electromagnetic wave shielding light transmitting window material.