JP3241348B2 - Method for manufacturing translucent electromagnetic wave shielding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excellent electromagnetic wave shielding effect capable of effectively shielding electromagnetic waves emitted from a display section of an electronic apparatus such as a CRT (CRT), a PDP (Plasma Display Panel). The present invention relates to a method for manufacturing a light-transmitting electromagnetic wave shielding member having a light-transmitting property.

[0002]

2. Description of the Related Art In recent years, various reports have been made on the effects of electromagnetic waves radiated from electric devices on the human body.
Accordingly, there is an increasing interest in techniques for shielding electromagnetic waves radiated from a surface screen such as a CRT. In order to shield electromagnetic waves radiated from an electric device, a method is generally known in which a housing of the electric device is made of a metal body or a metal plate is attached to the housing. However, for example, CRT or P
To shield the electromagnetic waves emitted from the DP display screen,
A metal plate cannot be used as it is because it is required to have an excellent electromagnetic wave shielding effect (shielding effect) and an excellent light transmission. Conventionally, for the purpose of shielding electromagnetic waves emitted from a display screen such as a CRT by covering the screen, for example, (1) a mesh made of a fiber mixed with a highly conductive metal filament, (2) stainless steel, tungsten Transparent substrate in which fibers of a conductive material such as
No. 4, JP-A-5-269912, JP-A-5-269912
327274) and (3) a transparent substrate having a metal or metal oxide vapor-deposited film formed on its surface (Japanese Patent Laid-Open No. 1-2
No. 7,880, JP-A-5-323101).

[0003]

However, when the mesh (1) is used, the display screen becomes dark, and the contrast and resolution are reduced. The transparent member of the above (2) has a problem that the manufacturing method becomes complicated and the cost becomes high and the display screen becomes dark because the fiber is embedded therein. In the case of the above (3), when the deposited film is made thin enough to maintain a sufficient translucency, the surface resistance of the film is reduced, and the attenuation characteristics of electromagnetic waves are also reduced. Incompatible with the shielding effect.

[0004] In addition to the above examples, ink or paint mixed with highly conductive metal powder is printed as a grid or stripe pattern by screen printing on a member that covers a display screen such as a CRT and shields electromagnetic waves. The formed transparent substrate (JP-A-62-57297, JP-A-9-2839)
Japanese Patent Application Laid-Open No. 2-52499 discloses a method in which a network-like pattern made of a conductive paint is printed on a surface of a transparent substrate by screen printing and baked in a vacuum. However, even if the above member is used, it is not possible to achieve both a sufficient electromagnetic wave shielding effect and a sufficient translucency.

Here, in order to achieve both an excellent electromagnetic wave shielding effect and an excellent translucency, it is necessary to optimize the line width of the pattern and the gap (pitch) between the patterns, and further reduce the electric resistance of the pattern. is there. No consideration has been given to such a viewpoint in the technique described in the above-mentioned publication, and it is considered that consideration for the method of forming a pattern is also insufficient. For example, in order to obtain sufficient translucency, it is preferable to make the line width of the pattern extremely thin and increase the interval between them, but in this case, the shielding effect becomes insufficient. Further, it is difficult to form a pattern having an extremely thin line width of several tens of μm by a method such as screen printing or the like, which causes problems such as variations in the line width of the pattern and generation of a large number of locations where the pattern is interrupted. .

On the other hand, in order to enhance the shielding effect, it is preferable to reduce the electrical resistance of the pattern as much as possible. However, in the case of a general conductive paste comprising conductive fine powder and a binder resin, the specific resistance is sufficiently small. However, when an extremely thin pattern is formed, the electric resistance between the patterns becomes extremely high, and it is difficult to sufficiently enhance the shielding effect. Here, if the film thickness of the pattern is increased, the electric resistance is reduced. However, it is extremely difficult to form a large film thickness for an extremely thin line width, and the viewing angle of the electromagnetic wave shielding member is narrow. It becomes one of the causes of lowering the translucency.

JP-A-3-35284 describes that a film made of a conductive material is formed on the surface of a transparent plastic substrate by vapor deposition and the like, and then patterned by chemical etching.
No. 82 describes that a geometric pattern made of a conductive material is provided on the surface of a transparent substrate by a chemical etching process.

According to the methods described in these patent publications, very fine patterns can be formed with high accuracy. However, in the etching process, since the photo phosphorus method is used to form a fine pattern, the manufacturing cost is extremely high, which is disadvantageous in cost. In particular, in order to support large screens such as PDPs,
Exposure equipment and etching equipment must be increased in size, and the manufacturing equipment becomes very expensive.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to manufacture a light-transmitting electromagnetic wave shielding member excellent in both light-transmitting properties and electromagnetic wave shielding effects by a simple method and at low cost. It is to provide a method.

[0010]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the present inventors have focused on a printing method which is advantageous in terms of cost as a pattern forming method.
As a result of intensive studies to apply an intaglio offset printing method using a blanket excellent in ink releasability since a fine pattern is formed with a line width of 40 μm, the present invention has been completed.

That is, the present invention provides: 1) a conductive black powder other than carbon (A), an average particle diameter of 30 nm or less, a channel black, a furnace black or a lamp, by an intaglio offset printing method using an ink release blanket. A conductive material mainly composed of carbon black (B), a binder resin (C) and a solvent (D) selected from carbon blacks for black coloring materials.
An electrically conductive resin composition , wherein the weight ratio of the conductive fine powder (A) to the carbon black (B) is A / B = 30.
0/1 to 20/1, and the conductive powder
(A) and the total amount of the carbon black (B),
When the weight ratio with the binder resin (C) is [(A) +
(B)] / (C) = 12/1 to 7/1 , using the conductive resin composition, the printed pattern is formed in a stripe shape or a grid shape on the surface of the transparent substrate. And the following formula (1): 1 ≦ Sk / Ss ≦ 9 (1) (where Ss is the total surface area of the printed electromagnetic wave shield pattern portion, and Sk is the surface of the transparent substrate) A method of manufacturing a light-transmitting electromagnetic wave shielding member, characterized by forming an electromagnetic wave shielding pattern that satisfies the following conditions: said selectively electroplating the shield pattern portion 1) a method of manufacturing a Kouki mounting of the light-transmitting electromagnetic wave shielding member, it is intended to cover.

According to the manufacturing method of the present invention, since an extremely fine pattern forming the electromagnetic wave shield pattern portion is formed by printing, it is possible to obtain a light-transmitting electromagnetic wave shield pattern member simply and at low cost. In addition, productivity can be improved and costs can be reduced. In addition, the light-transmitting electromagnetic wave shielding member obtained by the manufacturing method of the present invention has excellent light-transmitting properties because the printing pattern is very thin, several tens of μm, and carbon black is added to the conductive powder. With this, the resistance can be made very small even in a thin film having a thickness of several μm, and an excellent electromagnetic wave shielding effect is exhibited.
Even if the display screen of the RT tube or the like is covered, electromagnetic waves can be highly shielded without impairing the visibility of the display screen.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive resin composition used in the present invention has the composition and the mixing ratio as described above. The preparation method will be described below. In the present conductive resin composition, a typical example of the conductive powder (A) other than carbon is a metal powder, and specific examples thereof include powders of silver, copper, gold, nickel, and palladium. . These metal powders may be used alone or in combination of two or more, and may be a plated body (eg, silver-plated copper) or an alloy body. Among these metal powders, silver powder is particularly preferable because an oxide having high insulating properties is hardly generated, and copper powder is also preferably used.

The higher the packing density of the metal powder in the present conductive resin composition, the higher the conductivity of the electromagnetic wave shielding pattern portion and the higher the electromagnetic wave shielding effect. On the other hand, the conductivity of the electromagnetic wave shield pattern portion is not determined only by the volume resistivity of the metal powder itself to be used, but largely depends on the contact resistance between the metal powders in the pattern portion. For example, even if metal particles are densely filled inside the electromagnetic wave shielding pattern portion, if the contact resistance between the metal powders is large, the conductivity of the entire pattern becomes low.

The shape of the conductive powder (A) is not particularly limited, and may be spherical, scaly or millet-shaped, and may be 0.1 to 100 μm in size. Specifically, a scaly shape having a size of 0.1 to 20 μm is preferably used in consideration of increasing the contact surface between the metal powders. The conductive composition
Carbon black (B) in the product
Black, furnace black or lamp black
Used as fine powder having an average particle diameter of 30 nm or less.
You.

As the binder resin (C), for example, a thermoplastic resin such as a polyester resin, a polyimide resin, a polyethylene resin, a polystyrene resin, an acrylic resin, a polyamide resin, a phenol resin, an epoxy resin, an amino resin or a thermosetting resin. Can be used. The solvent (D) is used to prepare a viscous paste suitable for printing on a composition containing the conductive powder (A), carbon black (B) and the binder resin (C) by intaglio offset printing. Is added. As the solvent, for example, a solvent having a boiling point of 150 ° C. or more is suitable. When the boiling point of the solvent is lower than 150 ° C., the solvent tends to dry during printing, and the paste tends to change with time.

Specific examples of the solvent (D) include, for example, alcohols (eg, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, bentadecanol, stearyl alcohol, ceryl alcohol, cyclohexanol, Terpineol), alkyl ethers [ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monophenyl ether,
Diethylene glycol, diethylene glycol monobutyl ether (butyl carbitol), cellosolve acetate, butyl cellosolve acetate, potassium lupitol acetate, butyl carbitol acetate, etc.], and the like.

When a higher alcohol is used as the solvent, there is a possibility that the drying property and fluidity of the ink may be reduced. Therefore, butyl carbitol, butyl cellosolve, ethyl carbitol, butyl cellosolve acetate, which have better drying properties than these, may be used. Butyl carbitol acetate may be used in combination. In the conductive resin composition,
As described above, the mixing ratio of the conductive powder (A) to the carbon black (B) is (A) / (B) = 300/1 to 20 /
1 (weight ratio), more preferably from 200/1 to 4
0/1. The amount of the binder resin (C) used is, for example, [(A) + (B)] / (C) = 15 with respect to the total amount of the conductive powder (A) and the carbon black (B).
/ 1 to 5/1 (weight ratio), but more preferably 12/1 to 7/1.

In the above mixing ratio, (A) / (B)
Is greater than 300/1, the effect of improving the conductivity by carbon black (B) is no longer observed, while if it is less than 20/1, the conductivity is degraded. Further, in [(A) + (B)] / (C), 15
When the ratio is larger than / 1, the amount of the binder resin is too small, so that the printability, the strength of the coating film, etc. are significantly reduced,
Conversely, if the ratio is less than 5/1, the ratio of the conductive powder becomes too small, so that good conductivity cannot be obtained.

Next, as described above, the amount of the solvent (D) is appropriately selected so that the conductive resin composition becomes a paste having a viscosity suitable for printing by intaglio offset printing. The viscosity is usually adjusted so as to be 50 to 2,000 poise (P).
It is 00-1,000P. If the viscosity exceeds the above range, printability is reduced and a fine pattern cannot be formed,
Conversely, if the ratio is lower than the above, the ratio of the conductive powder in the paste becomes small, and the conductivity is not sufficiently satisfied.

The conductive resin composition is, as described above,
It can be prepared by mixing a predetermined amount of each component of (A), (B), (C) and (D), sufficiently stirring and mixing, and kneading. As shown in FIG. 1, for example, as shown in FIG. 1, a transparent electromagnetic wave shielding member 1 which is an object of the manufacturing method of the present invention has an electromagnetic wave shielding pattern portion 10 made of the conductive resin composition printed on the surface of a transparent substrate 2. Things. Hereinafter, a method of forming the electromagnetic wave shielding pattern will be described.

The pattern shape of the electromagnetic wave shield pattern portion includes, for example, a stripe pattern 11 shown in FIG.
The grid-like patterns 12 and 13 shown in FIGS. 3 and 4 are exemplified. The pattern shape of the electromagnetic wave shield pattern portion may be a geometric pattern in addition to the above-mentioned stripe shape and lattice shape. That is, for example, a triangle such as an equilateral triangle, an isosceles triangle, and a right triangle; a square, a rectangle, a rhombus,
Squares such as parallelograms and trapezoids; (regular) hexagons, (positive) octagons, (positive) dodecagons, (positive) N-gons such as decagons; circles, ellipses, stars, etc. A geometric pattern obtained by repeating various graphic units may be used as the electromagnetic wave shield pattern unit 10. In such a geometric pattern, the graphic unit may be a combination of two or more types. Further, from the viewpoint of smoothly removing static electricity from the electromagnetic wave shielding member, it is preferable that each figure unit in the geometric pattern is continuous.

As a specific example of a pattern shape composed of a geometric pattern, for example, as shown in FIG.
(A)), a rhombus pattern (FIG. 5 (b)), a regular hexagonal pattern (FIG. 5 (c)), and the like. FIG.
In (c), the hatched portion indicates the electromagnetic wave shield pattern portion 10, and the non-hatched portion indicates the region 20 where the pattern portion is not formed.

In the case where the pattern has a rectangular lattice shape, there are two types of pattern line intervals. In this case, it is sufficient that each line interval is within a predetermined range described later. In the case where the pattern is a geometric pattern, the line width refers to the width of one unit (that is, a constituent unit such as a triangle, a quadrangle, an N-gon, a circle, an ellipse, etc.) constituting the geometric pattern. Means the distance between the units, finds the square root of the area of one unit (that is, the length of one side when one unit is squared), and calculates the square root from the distance at the center position between adjacent units. The subtracted value is the distance between units.

In the present invention, the pattern of the electromagnetic wave shield pattern portion 10 is changed to a stripe pattern 11 shown in FIG. 1, a grid pattern 12 shown in FIGS.
13, when the line width of the pattern portion 10 is 5 to 40 μm
m and the following equation (1): 1 ≦ Sk / Ss ≦ 9 (1) (where Ss and Sk have the same meanings as described above).

It is difficult to form the pattern portion 10 so that the line width is less than 5 μm, and the line is apt to be broken, which leads to a decrease in the electromagnetic wave shielding effect. Conversely, if the line width exceeds 40 μm, the pattern portion 10 becomes easily recognizable visually, leading to a decrease in light transmission. The line width is particularly preferably from 10 to 30 μm in the above range. On the other hand, if the value of Sk / Ss is smaller than 1, the pattern area becomes large and the translucency is reduced, and if it is larger than 9, the electromagnetic wave shielding effect is reduced. Sk /
The value of Ss is preferably 5 to 8 in the above range.

As the transparent substrate used in the present invention, a glass or a film having sufficient transparency to visible light is used. After printing the conductive resin composition on the transparent substrate, a heating step or a heating step is performed. A material having sufficient heat resistance is preferable because it undergoes an ultraviolet irradiation step. Specifically, soda lime glass, polycarbonate, polyether sulfone (PES resin), polymethyl methacrylate (PMMA resin), polyimide resin, polyethylene terephthalate (PET resin) and the like are mentioned, and among them, very high permeability is provided. PET films are desirable because they are good and inexpensive.

Although the thickness of the transparent substrate is not particularly limited,
From the viewpoint of maintaining the translucency of the electromagnetic wave shielding member, the thinner the better. That is, it is usually set in the range of 0.05 to 5 mm depending on the form (film shape, sheet shape) at the time of use and the required mechanical strength. In the present invention, as described above, the translucent electromagnetic wave shielding member is formed by printing an electromagnetic wave shielding pattern portion on the transparent base material in a predetermined pattern by an intaglio offset printing method using a blanket having excellent ink release properties. Then, it is manufactured by heat curing or ultraviolet curing.

The intaglio offset printing method is excellent in that the linearity of the formed line is good and an extremely fine pattern can be reproduced with high precision. Further, by using a blanket having excellent ink release properties, a pattern having a uniform thickness can be formed even when the line width of the pattern is extremely small. Examples of the intaglio used in the present invention include a flat plate having a predetermined concave portion formed on the surface of a substrate, a flat plate wound, a cylindrical plate, and a columnar plate.

Examples of the base material include soda lime glass, non-alkali glass, quartz, low alkali glass,
In addition to glass substrates such as low expansion glass, fluorine resin, polycarbonate (PC), polyether sulfone (PE
S), a resin plate of polyester, polymethacrylic resin, etc.
Metal substrates such as stainless steel, copper, nickel, and low expansion alloy invar can be used. Above all, it is particularly preferable to use a glass-made one which can form the edge shape of the pattern very sharply.

The intaglio concave portion is formed by a photolithography method, an etching method, an electroforming method, or the like, as in the prior art. The line width, cotton interval, and depth of the intaglio recess are appropriately set within the above-described range according to the shape of the electromagnetic wave shield pattern portion. The blanket used in the present invention is not particularly limited as long as it is excellent in the releasability of the ink, and examples thereof include a blanket whose surface is made of silicone rubber, fluororesin, fluororubber or a mixture thereof. . Among them, silicone rubber is excellent in ink releasability and is preferably used. Examples of the silicone rubber include various types of silicone rubber such as a millable type, a room temperature curing type, and an electron beam curing type. Among them, a room temperature curing type addition type silicone rubber generates no by-products at the time of curing. In addition, a thin printed coating film can be reproduced with high accuracy, and therefore, it is preferably used.

As an index indicating the ink releasability of the blanket, for example, the surface energy of the blanket surface can be mentioned, and its value is preferably 15 to 30 dyn / cm, more preferably 18 to 25 dyn / cm. preferable. The surface rubber layer made of these silicone rubbers
The surface is preferably smooth, and specifically, the surface roughness is preferably 0.5 μm or less in terms of 10-point average roughness,
More preferably, it is 0.3 μm or less. The hardness (JIS-A) of the silicone rubber is preferably 20 to 80 degrees, more preferably 30 to 60 degrees.

The support of the blanket may be any as long as it has a flat surface, such as polyethylene terephthalate (PET), polyether sulfone (PES),
Plastics such as polyester and polycarbonate (PC), and metal plates such as aluminum and stainless steel can be used. A porous layer may be formed between the surface rubber layer and the support.

The shape of the transfer member is a sheet-like member wound around a cylindrical body, a roller-like member, or a curved elastic member used for pad printing or the like if there is no printing displacement. You may. In the case of a thermosetting ink, the pattern of the conductive resin composition printed and formed on the transparent substrate is cured by heating at 80 to 250 ° C. for 10 to 120 minutes. In the case of an ultraviolet curable ink, the ultraviolet light should be 1-1.
Irradiated for 0 minutes. Thus, an electromagnetic wave shielding member as an object of the present invention is obtained.

Next, by performing electrolytic plating, the resistance can be further reduced, and the electromagnetic wave shielding property can be further improved. As electrolytic plating, resistance,
Electrolytic copper plating is effective in view of cost. Such electrolytic copper plating is performed by reducing copper ions in a copper plating solution by an electrolysis reaction and depositing copper on a conductive pattern portion provided on a cathode (electrodeposition). It is necessary to have the conductivity required for the electrolysis reaction, and the smaller the electric resistance, the shorter the electrolysis time can be set and the higher the productivity.

Examples of the copper plating solution used for the electrolytic copper plating include an acidic bath such as a copper sulfate plating solution and a Hofuka copper plating solution, and an alkaline bath such as a copper pyrophosphate plating solution and a copper cyanide plating solution. Among them, it is preferable to use a copper pyrophosphate solution which is excellent in uniform electrodeposition property and fine particle plating and has low toxicity of the plating solution. Plating conditions are appropriately set according to the thickness of the coating layer. The thickness of the coating layer is set in consideration of both the shielding property and the productivity, and is usually 1 μm to 10 μm. Even if the thickness is 10 μm or more, the shielding performance is almost the same without change.

[0037]

EXAMPLES The present invention will be described more specifically with reference to examples along with comparative examples. Examples 1 to 8 and Comparative Examples 1 to 7 [Preparation of Conductive Resin Composition] (A) Conductive Fine Powder; A flaky silver powder having a particle size of 0.2 to 10 μm was used. (B) Carbon black; the following three types were used.

Carbon black (1): conductive carbon black Printex XE2 (manufactured by Degussa) carbon black (2): high-grade carbon blank Col
or BlackFW200 (made by Deggsa) carbon black (3): high-grade carbon black # 2
600B (manufactured by Mitsubishi Chemical Corporation) (C) Binder resin; the following polyester resin was used (manufactured by Sumitomo Rubber Industries, Ltd.).

Ester of trimellitic anhydride and neobentyl glycol (weight average molecular weight: 20,000) (D) Solvent: butyl carbitol acetate was used. In addition, amine-blocked p-paratoluenesulfonic acid was used as a curing catalyst. The amount added was 5 parts by weight with respect to 100 parts by weight of the resin in all the formulations.

The above polyester resin, silver powder, carbon black (1) to (3), and a solvent were blended in the composition shown in Table 1, and after the curing catalyst was added in the above amounts, the mixture was thoroughly stirred and mixed. The conductive resin composition was prepared by kneading with this roll. In the intaglio printing, the line width of the printed matter is 25 μm and the line interval is 225.
The concave shape was set so as to be μm (closing rate 81%, Sk / Ss = 4.3).

[Measurement of Specific Resistance] The specific resistance of the conductive resin composition prepared with the composition shown in Table 1 was measured. The results are also shown in [Table 1]. Here, the specific resistance was measured by the following method. 100 ℃ × 1hour and 150 ℃ × 1
The conductive resin composition cured by heating for 4 hours was measured with a four-probe resistance meter (Loresta IP ICP-T25 manufactured by Mitsubishi Yuka).
0) and was calculated. [Preparation of Transparent Electromagnetic Wave Shielding Member] A transparent polyethylene terephthalate (PE) having a thickness of 0.1 mm is formed on a transparent substrate.
T) Film was used.

When the electromagnetic wave shield pattern portion was formed by intaglio offset printing, an intaglio plate made of soda-lime glass having a predetermined pattern was used.
The surface of the blanket is made of silicone rubber (JIS-A
Additional RTV silicone rubber with a hardness of 40 degrees, ten-point average roughness of the surface of 0.3 μm, surface free energy of 21 dyn /
cm) of a silicone blanket.

The conductive resin composition obtained above is printed on the transparent substrate by the intaglio offset printing method using the silicone blanket and the intaglio, and then cured by heating in an oven at 130 ° C. for 1 hour. Thus, a translucent electromagnetic wave shield member having a lattice-like electromagnetic wave shield pattern portion was obtained. [Evaluation of Physical Properties of Transparent Electromagnetic Wave Shield Member] The following physical property evaluations were performed on the translucent electromagnetic wave shield members obtained in the above Examples and Comparative Examples. The results are shown in [Table 1].

Electromagnetic Wave Shielding Property Electromagnetic wave shielding performance in a frequency range of IMHz to 300 MHz was measured by the KEC method of Kansai Electronics Industry Promotion Center. Table 1 shows the evaluation results of the attenuation rate at 300 MHz. Evaluation criteria ×: 0 to 30 dB Δ: 30 to 45 dB ○: 45 dB or more Visibility evaluation (1) Affixed to the front surface of a PDP panel and visually evaluated according to the following criteria.

Evaluation Criteria: The pattern is visible. ：: The pattern cannot be confirmed.

[0046]

[Table 1]

As is evident from the results shown in Table 1, in Examples 1 to 8, the paste was prepared by blending carbon black with silver powder at a weight ratio of 1/300 to 22.5 / 1. Has a lower specific resistance (improves conductivity),
Electromagnetic shielding is improved. In addition, the curing temperature is 130 ° C
In the case of 100 ° C., the difference in specific resistance is greater when carbon is added and when carbon is not added than in the case of, and considering the heat resistance of the transparent substrate, etc. It can be said to be advantageous. Examples 9 to 14 and Comparative Examples 8 to 13 The conductive paste of Example 4 was used, and
Printing was performed using an intaglio having a line width and a line interval, and an electromagnetic wave shielding member was produced in the same manner as in the above-described embodiment.

With respect to the produced electromagnetic wave shielding member, evaluation of electromagnetic wave shielding property and visibility evaluation (1) were performed in the same manner as in Table 1. The visibility evaluation (2) was evaluated according to the following criteria. The results are shown in [Table 2]. Visibility evaluation (2) Affixed to the front surface of the PDP panel and visually evaluated according to the following criteria.

Evaluation Criteria: The screen was very dark. Δ: The screen became slightly dark. ：: The screen was not so dark.

[0050]

[Table 2]

From the results shown in Table 2, by adjusting the line width and the cotton interval and adjusting the Sk / Ss value to 1 or more and 9 or less, the visibility (transmittance) is maintained while the electromagnetic wave shielding property is maintained at a certain level or more. )
It can be seen that the improvement of the above can be achieved. Comparative Example 14 Using the conductive paste used in Example 4, a screen printing machine attempted grid patterning with a line width of 35 μm and a line interval of 300 μm, but the line width varied and the pattern was disconnected. Many were seen. Therefore, P
When the film was attached to the front of the DP and visually evaluated, unevenness was found overall. In addition, because the pattern was broken, the electromagnetic wave shielding performance was poor. Comparative Example 14 The conductive paste used in Example 4 was patterned by a screen printing machine in a grid pattern having a line width of 35 μm and a line interval of 300 μm. However, the cotton width varied, and there were many places where the pattern was broken. Was seen. Therefore, PDP
When the film was attached to the front surface and visually evaluated, unevenness was found overall. Further, since the pattern was broken, the electromagnetic wave shielding performance was poor.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a translucent electromagnetic shield member, and FIG. 1B is an enlarged cross-sectional view of the AA portion.

FIG. 2 is a schematic diagram showing an example of a stripe pattern.

FIG. 3 is a schematic diagram showing an example of a lattice pattern.

FIG. 4 is a schematic view showing another example of a lattice pattern.

FIGS. 5A to 5C are schematic diagrams showing examples of geometric patterns. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent electrode shield member 2 Transparent base material 10 Electromagnetic shield pattern part 11 Stripe pattern 12 Lattice pattern 13 Lattice pattern WS Line width Wk Line spacing Wt Film thickness

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2000-13088 (JP, A) JP-A-5-75290 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 9/00

Claims (2)

(57) [Claims] 1. A conductive fine powder other than carbon (A), having an average particle diameter of 30 n by an intaglio offset printing method using an ink releasable blanket.
m or less, a conductive resin composition mainly composed of carbon black (B), a binder resin (C) and a solvent (D) selected from carbon blacks for coloring materials of channel black, furnace black or lamp black.
It is one, the weight ratio of the conductive fine powder (A) and the carbon black (B) is, A / B = 300 / 1~20 /
1 and the conductive powder (A) and the car
Bonblack (B) and the binder resin
The weight ratio with (C) is [(A) + (B)] / (C) = 1
Using the conductive resin composition in the range of 2/1 to 7/1 , the printed pattern is formed in a stripe or grid pattern on the surface of the transparent substrate, and the line width of the pattern is 5 to 40 μm.
And the following equation (1): 1 ≦ Sk / Ss ≦ 9 (1) (where Ss is the total surface area of the printed electromagnetic wave shield pattern portion, and Sk is the electromagnetic wave shield pattern portion formed on the surface of the transparent substrate. Wherein the total area of the non-existing regions is shown). Wherein After intaglio offset printing method according to claim 1 Symbol placement of the light-transmitting electromagnetic wave shielding member for selectively electroplating the electromagnetic wave shielding pattern portion.