JP3398092B2 - Transparent electromagnetic wave shielding member and method of manufacturing the same - Google Patents

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 effect and a transmission effect that can effectively shield an electromagnetic wave emitted from a display portion of an electronic device such as a CRT (CRT) or PDP (plasma display panel). The present invention relates to a translucent electromagnetic wave shield member having excellent lightness and visibility and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, various reports have been made on the effects of electromagnetic waves emitted from electrical equipment on the human body.
Accompanying this, there is increasing interest in technology for shielding electromagnetic waves radiated from a surface screen such as a CRT. In order to shield the electromagnetic waves emitted from an electric device, a method is generally known in which the casing of the electric device is made of a metal body or a metal plate is attached to the casing. 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 excellent electromagnetic wave shielding effect (shielding effect) as well as excellent translucency. 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 fibers mixed with a highly conductive metal filament, (2) stainless steel, Transparent base material in which fibers of a conductive material such as tungsten are embedded (Japanese Patent Laid-Open No. 3-352)
84, JP-A-5-269912, JP-A-5
No. 327274), and (3) a transparent substrate having a vapor-deposited film of metal or metal oxide formed on the surface (Japanese Patent Application Laid-Open No. HEI-1-
No. 27880 and Japanese Patent Laid-Open No. 5-323101) are used.

[0003]

However, when the mesh of the above (1) is used, the display screen becomes dark and the contrast and resolution are lowered. The transparent member of the above (2) has a problem that the manufacturing method is complicated and the cost is high and the display screen is dark because the fiber is embedded inside. Further, in the case of (3), when the vapor deposition film is thinned to the extent that sufficient translucency can be maintained, the surface resistance of the film is lowered and the attenuation property of electromagnetic waves is also lowered. It cannot be compatible with the shielding effect.

In addition to the above examples, a member such as a CRT that covers a display screen and shields electromagnetic waves is printed with an ink or paint mixed with highly conductive metal powder as a grid or striped pattern by screen printing. Formed transparent substrate (JP-A-62-57297, JP-A-9-2839)
No. 77), a mesh pattern made of a conductive paint is printed on the surface of a transparent substrate by screen printing and baked in vacuum (Japanese Patent Laid-Open No. 52499/1990). 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 light-transmitting property, it is necessary to optimize the pattern line width and the pattern gap (pitch) and further reduce the electric resistance of the pattern. is there. It is considered that such a viewpoint is not considered in the technique described in the above publication, and that the method for creating a pattern is also insufficiently considered. For example, in order to obtain sufficient translucency, it is preferable that the line width of the pattern be extremely thin and the interval be large, but in this case, the shielding effect becomes insufficient. Further, it is difficult to form a pattern having an extremely narrow line width of several tens of μm by a method such as screen printing, and there are problems such as variations in the line width of the pattern and a large number of places where the pattern is interrupted. Occurs.

On the other hand, in order to enhance the shielding effect, it is preferable to lower the electric resistance of the pattern as much as possible, but in the case of a general conductive paste composed of 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 very high, and it is difficult to sufficiently enhance the shielding effect. Further, in order to suppress the reduction in the contrast of the display, it is necessary to make the pattern black. Therefore, if carbon or the like is used as the conductive powder, the paste can be blackened, but the conductivity is lowered and the electromagnetic wave shielding property is deteriorated.

Japanese Unexamined Patent Publication (Kokai) No. 3-35284 describes that a film made of a conductive material is formed on the surface of a transparent plastic substrate by vapor deposition or the like, and then patterned by chemical etching.
Japanese Patent Publication 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, a very fine pattern can be formed with high accuracy. However, since the photolithography method is used to form a fine pattern in the etching process, the manufacturing cost becomes extremely high, which is disadvantageous in terms of cost. In particular, in order to support large screens such as PDP,
The size of the exposure apparatus and the etching apparatus must be increased, and the manufacturing apparatus becomes very expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a transparent electromagnetic wave shield member which is excellent in both transparency and electromagnetic wave shielding effect and has good visibility, and a simple and low cost It is to provide a manufacturing method for manufacturing.

[0010]

In order to solve the above-mentioned problems, the inventors of the present invention focused on a printing method which is advantageous in terms of cost as a pattern forming method, and particularly, a fine pattern having a line width of 5 to 40 μm. The present invention has been completed as a result of earnestly researching to apply an intaglio offset printing method using a blanket having excellent ink releasability.

That is, the present invention mainly includes the following contents. 1) An electromagnetic wave shielding member having a pattern formed by printing a conductive paste containing metal powder on the surface of a transparent substrate, wherein the metal powder is (a) silver, copper, or silver.
One or more scale-like metal powders selected from the group of coated copper powders and (b) either spherical powders of palladium or platinum and having a weight ratio of (a) / (b) of 99.
9 / 0.1 to 50/50, and the total area (Ss) of the region of the transparent substrate where the shield pattern is formed.
And the total area (Sk) of the region where the shield pattern is not formed satisfy 1 ≦ Sk / Ss ≦ 9, the line width Ws of the shield pattern is 5 to 40 μm, and the film thickness Wt is 0.
A translucent electromagnetic wave shield member having a thickness of 5 to 50 μm.

2 ) In forming an optically transparent electromagnetic wave shield pattern on the surface of a transparent substrate by an intaglio printing method using a blanket having ink releasability, (1) forming a shield pattern, (a) silver, There is copper
One or more selected from the group of copper powder coated with silver or silver
Of the scaly metal powder of (b) and spherical powder of (b) palladium or platinum, and the weight ratio of (a) / (b) is 99.9 / 0.1-50 / 50. (2) The line width of the pattern is 5 to 40 μm, and the film thickness is 0.5 to
50 μm, and (3) the relationship between the total area (Ss) of the area printed with the electromagnetic wave shield pattern printed on the surface of the transparent substrate and the total area (Sk) of the area not formed with the electromagnetic wave shield pattern. Formula (1): 1 ≦ Sk / Ss ≦ 9 (1) A pattern is formed so as to satisfy, and then a method of manufacturing a transparent electromagnetic wave shield member is characterized by curing.

3 ) The method for producing a translucent electromagnetic wave shield member according to 2 ), wherein the blanket has a surface rubber made of silicone rubber.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the translucent electromagnetic wave shield member of the present invention, as described above, the metal powder comprises (a) scale-like metal powder and (b) either spherical powder of palladium or platinum and (a) ) / (B) weight ratio is 99.9 / 0.1
A pattern part is produced using a conductive paste composition of -50/50.

The scale-like metal powder referred to in (a) above is a metal powder other than palladium and platinum, where R <1.0 × 10 ⁻⁵ , where R is the volume resistivity of the metal.
However, silver powder, copper powder or copper powder coated with silver is preferable, and these may be used alone or in combination of two or more. The scale-like powder referred to here generally has a length of 0.1 to 20.
μm, width 0.05 to 15 μm, thickness 0.05 to 5 μm
A powder having a scale shape of about m is preferable. Among the scale-like powders, silver powder is particularly preferable in terms of conductivity.

Next, the spherical powder of palladium or platinum mentioned in (b) above complements the scale-like metal powder of (a) to improve the filling efficiency of the whole metal powder, and improves the surface of the scale-like metal powder. It is added for the purpose of quality. This spherical powder is
The particle diameter is preferably 5 μm or less for the purpose of enhancing the filling efficiency. The scale-like metal powder of (a) and the spherical powder of palladium or platinum of (b) are 99.9 as described above.
/0.1≤a/b≤50/50 in a weight ratio.
When the ratio of a / b is less than 99.9 / 0.1, the effect of addition is not observed, while this ratio is 50
When it exceeds / 50, the electric resistance of the conductive paste becomes higher than that when the scale-like metal powder is used alone.

From the viewpoint of increasing the conductivity of the electromagnetic wave shielding pattern portion to further enhance the electromagnetic wave shielding effect, the above-mentioned conductive paste composition increases its packing efficiency, that is, the packing density. Is preferably 2 g / cm ³ or more. On the other hand, the conductivity of the electromagnetic wave shield pattern portion is not only determined by the volume specific resistance of these metal powders themselves, but is greatly influenced by the contact resistance between the metal powders in the pattern portion. For example, even if the inside of the electromagnetic wave shield pattern portion is filled with metal particles at a high density, if the contact resistance between the metal powders is large, the conductivity of the entire pattern becomes low.

The above-mentioned conductive paste composition is prepared by mixing the above-mentioned metal powders (a) and (b) with a binder resin and a solvent. As the binder resin, any of thermosetting type, ultraviolet curing type and thermoplastic type can be used. Examples of thermosetting resins include polyester-melamine, melamine, epoxy-melamine, phenol, polyimide, acrylic, and polyurethane resins. Examples of the ultraviolet curable type include acrylic resin, and examples of the thermoplastic type include polyester, polyvinyl butyral, acryl, phenol, polyurethane and other resins. When a thermosetting resin is used, a curing catalyst such as p-toluenesulfonic acid, amine-blocked p-toluenesulfonic acid, or blocked isocyanate is added, if necessary, when the curing temperature cannot be increased. It is preferable.

The solvent is added to the formulation containing the metal powder of (a) and (b) and the binder resin to prepare a viscous paste suitable for printing by the intaglio offset printing method. . As the solvent, for example, a solvent having a boiling point of 150 ° C. or higher is suitable. The boiling point of the solvent is 15
When the temperature is lower than 0 ° C, the paste is easily dried during printing, and the paste is apt to change with time.

Specific examples of the solvent include alcohols (eg, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, bentadecanol, stearyl alcohol, ceryl alcohol, cyclohexanol, terpineol). And alkyl ethers [eg, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monophenyl ether, diethylene glycol, diethylene glycol monobutyl ether (butyl carbitol), cellosolve acetate, butyl cellosolve acetate, rupitol acetate, butyl carbitol acetate, etc.] And the like, and is appropriately selected in consideration of printability and workability.

When a higher alcohol is used as the solvent, the drying property and fluidity of the ink may be deteriorated. Therefore, butyl carbitol, butyl cellosolve, ethyl carbitol, butyl cellosolve acetate, which has a better drying property than these, may be used. Butyl carbitol acetate may be used in combination. In the conductive paste composition, the metal powders (a) and (b) are generally 100 to 2000 parts by weight with respect to 100 parts by weight of the binder resin,
It is preferably added in a proportion of 200 to 1000 parts by weight.

On the other hand, as described above, the amount of the solvent added is appropriately selected so that the conductive resin composition becomes a paste having a viscosity suitable for printing by the intaglio offset printing method. The viscosity is usually adjusted to be 50 to 2,000 poise (P), but the preferable range is 20.
It is 0 to 1,000P. When the viscosity exceeds the above range, printability is deteriorated and a fine pattern cannot be formed. On the contrary, when the viscosity falls below the ratio of the conductive powder in the paste, the conductivity cannot be sufficiently satisfied.

Appropriate additives may be added to the conductive paste composition for the purpose of quality improvement and the like. For example, by adding a black pigment or a black dye, the visibility of the electromagnetic wave shield panel can be improved. Examples of the black pigment include carbon black, but the kind and shape thereof are not particularly limited, and include channel black, carbon black for coloring materials such as furnace black or lamp black, and conductive carbon black and acetylene black. However, fine powder having an average particle diameter of 20 nm or less is preferably used.

In the present invention, the conductive paste composition is
It can be prepared by mixing the above-mentioned components in a predetermined amount, sufficiently stirring and kneading by a conventional method. In the present invention, the transparent electromagnetic wave shield member 1 is, for example, as shown in FIG. 1, an electromagnetic wave shield pattern portion 10 formed by printing on the surface of a transparent substrate 2 using the conductive paste composition. In this shield pattern, the line width of the pattern is 5 to 40 μm, the film thickness is 0.5 to 50 μm, and the total surface area (Ss) of the electromagnetic wave shield pattern portion printed on the surface of the transparent substrate and the electromagnetic wave shield pattern portion are formed. The relation with the total area (Sk) of the unfilled region is formed so as to satisfy the formula (1): 1 ≦ Sk / Ss ≦ 9 (1).

It is difficult to form the pattern portion 10 so that the line width thereof is less than 5 μm, and disconnection is likely to occur, resulting in a reduction in the electromagnetic wave shielding effect. On the contrary, if the line width exceeds 40 μm, the electromagnetic shielding performance will be deteriorated if the aperture ratio is increased for the purpose of improving the screen transparency. The line width is preferably 10 to 30 μm in the above range. As for the film thickness, when the thickness is less than 0.5 μm, the shielding effect is weak, and when it exceeds 50 μm, the viewing angle becomes narrow, which causes a problem in visibility.

On the other hand, if the value of Sk / Ss is smaller than 1, the pattern area becomes large and the translucency is deteriorated. On the contrary, if it is larger than 9, the electromagnetic wave shielding effect is deteriorated. The value of Sk / Ss is 5 to 5 in the above range.
8 is preferred. Next, a method of forming the transparent electromagnetic wave shield pattern will be described. The translucent electromagnetic wave shield pattern can be produced by printing an electromagnetic wave shield pattern portion on a transparent substrate in a predetermined pattern by an intaglio offset printing method using a blanket excellent in ink releasability, and then 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 printed and reproduced with high accuracy. Furthermore, by using a blanket having excellent ink releasability, it is possible to form a pattern having a uniform thickness even when the line width of the pattern is extremely narrow. Examples of the intaglio plate used in the present invention include a flat plate-shaped plate having a predetermined recess formed on the surface of the substrate, a flat plate-shaped plate wound around it, a cylindrical plate, and a columnar plate. The depth of the intaglio may be designed according to the desired ink film thickness, but is usually about 1 to 50 μm.

Examples of the substrate include soda lime glass, non-alkali glass, quartz, low alkali glass,
In addition to glass substrates such as low expansion glass, fluororesin, polycarbonate (PC), polyether sulfone (PE
S), polyester, resin plate such as polymethacrylic resin,
A metal substrate such as stainless steel, copper, nickel, or low expansion alloy amber can be used. Above all, it is particularly preferable to use a glass-made material that can form the edge shape of the pattern very sharply.

The intaglio recess is formed by a photolithography method, an etching method, an electroforming method, or the like, as in the conventional case. The line width, the cotton interval, and the depth of the intaglio concave portion are appropriately set within the range described above according to the shape of the electromagnetic wave shield pattern portion. In the intaglio printing method of the present invention, when a transfer body having a silicone rubber outermost layer is used, it is possible to print a very thin pattern having a line width of several tens of μm as described above. Become. As the silicone rubber, there are basically room temperature curable type and heat curable type. Among them, the room temperature curable addition type silicone rubber does not generate any by-products at the time of curing and is capable of printing a thin film. It is preferably used because the coating film can be reproduced with high accuracy.

The surface rubber layer made of these silicone rubbers preferably has a smooth surface, and specifically, the surface roughness is preferably 10 μm or less in terms of 10-point average roughness, and more preferably. It is 0.3 μm or less. The hardness (JIS-A) of the silicone rubber is preferably 10 to 70 degrees, more preferably 20 to 60 degrees.

The blanket support may have any flat surface, for example, 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-shaped member wound around a cylindrical cylinder, a roller-shaped member, or a curved elastic member used for pad printing or the like if it does not cause print misalignment. May be. As the transparent substrate used in the present invention, glass or film having sufficient translucency to visible light is used, but after printing the conductive paste composition on the transparent substrate, a heating step or an ultraviolet irradiation step Therefore, those having sufficient heat resistance are preferable. Specifically, as a film, a polyester system represented by polyethylene phthalate (PET), a polyolefin system such as polyethylene, polypropylene and polystyrene, a vinyl system such as polyvinyl chloride and polyvinylidene chloride, a polyether sulfone, a polycarbonate, a polyamide, Examples include polyimide and acrylic resin. Among these, a PET film which has good transparency and is inexpensive is preferable. In addition to the film, glass (eg, soda lime glass) can be used.

The thickness of the transparent substrate is not particularly limited,
From the viewpoint of maintaining the transparency of the electromagnetic wave shield 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 or sheet) in use and the required mechanical strength. The pattern formed by printing using the conductive paste composition on the transparent substrate is 10 to 1 at 80 to 250 ° C. in the case of a thermosetting ink.
Heat cured for 20 minutes. Further, in the case of an ultraviolet curable ink, ultraviolet rays are irradiated for 1 to 10 minutes. Thus, the transparent electromagnetic wave shield member which is the object of the present invention is obtained.

The pattern shape of the electromagnetic wave shield pattern portion in the present invention is appropriately selected. For example, the stripe pattern 11 shown in FIG. 2 and the grid patterns 12 and 13 shown in FIGS. The pattern shape of the electromagnetic wave shield pattern portion may be a geometric pattern in addition to the stripe shape and the grid shape. That is, for example, a triangle such as an equilateral triangle, an isosceles triangle, and a right triangle; a square such as a rectangle, a rectangle, a rhombus, a parallelogram, and a trapezoid; a (regular) hexagon, a (regular) octagon, a (regular) dodecagon,
(Orthogonal) N-gon such as (regular) decagon; geometrical pattern obtained by repeating various graphic units such as circle, ellipse and star may be used as the electromagnetic wave shield pattern portion 10. In such a geometric pattern, the graphic units may be a combination of two or more kinds. Further, from the viewpoint of smoothly removing the electric charge of the electromagnetic wave shield member, it is preferable that each figure unit in the geometric pattern is continuous.

As a concrete example of the geometrical pattern, for example, as shown in FIG. 5, a circular pattern (see FIG.
(A)), diamond pattern (FIG. 5 (b)), regular hexagonal pattern (FIG. 5 (c)) and the like. FIG. 5 (a)-
In (c), the hatched portion indicates the electromagnetic wave shield pattern portion 10, and the non-hatched portion indicates the region 20 in which the pattern portion is not formed.

When the pattern has a rectangular grid pattern, there are two types of line intervals in the pattern. In this case, each line interval may be within a predetermined range described later. When the pattern is a geometric pattern, the line width means the width of one unit (that is, a structural unit such as a triangle, a quadrangle, an N polygon, a circle, an ellipse, etc.) that constitutes the geometric pattern. , Is the distance between units, and calculates the square root of the area of one unit (that is, the length of one side when one unit is restrained as a square), 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 shape of the electromagnetic wave shield pattern portion 10 is the stripe pattern 11 shown in FIG. 1, the grid pattern 12 shown in FIGS.
13 or the geometric pattern shown in FIG. The translucent electromagnetic wave shield member of the present invention can be further reduced in resistance by performing electrolytic plating, and the electromagnetic wave shield property can be further improved.

Electrolytic copper plating is effective in terms of resistance and cost. Such electrolytic copper plating reduces copper ions in the copper plating solution by an electrolysis reaction,
It is carried out by depositing copper (electrodeposition) on the conductive pattern part installed on the cathode, but the conductive pattern part needs to have the conductivity necessary for the electrolysis reaction, and the smaller the electric resistance, the longer the electrolysis time. Can be set short and productivity can be improved. When electrolytic plating (electrolytic copper plating) is performed after pattern printing, the adhesiveness of the plating is better if a copper paste is prepared from copper powder and used.

Examples of the copper plating solution used for the above-mentioned electrolytic copper plating include an acid bath such as a copper sulfate plating solution and a boro-fukka copper plating solution, or an alkaline bath such as a copper pyrophosphate plating solution and a copper cyanide plating solution. Above all, 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. The 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 shield property and the productivity, but it is usually 1 μm to 10 μm, and even if the thickness is 10 μm or more, the shield performance is almost the same.

[0040]

According to the present invention, an extremely fine patterns constituting the electromagnetic wave shielding pattern portion since the formation by printing, it is possible to obtain a light-transmitting electromagnetic wave shielding member with a simple and low cost production It is possible to improve the property and reduce the cost. In addition, the transparent electromagnetic wave shield member of the present invention is excellent in translucency because the printed pattern is very thin, several tens of μm, and the film thickness is several μm.
The resistance can be made extremely small even with a thin film such as m, and the excellent electromagnetic wave shielding effect is exhibited. Therefore, even if the display screen of a CRT tube or the like is covered with the member, the visibility of the display screen is not impaired, and Can be highly blocked.

[0041]

[Preparation of conductive paste composition]

(1) Scale-like silver powder: length 0.2 to 10 μm, thickness 0.
A scaly material having a width of 1 to 2.0 μm and a width of 0.1 to 8 μm was used.

(2) Spherical powder of palladium or platinum:
In each case, spherical particles having an average particle diameter of 1 μm were used. (3) Binder resin: ester of trimellitic anhydride and neopentyl glycol (weight average molecular weight: 20,0)
The thermosetting polyester resin (00) manufactured by Sumitomo Rubber Industries, Ltd. was used. (4) Curing catalyst: amine block p obtained by neutralizing diethanolamine and p-toluenesulfonic acid
-Using paratoluenesulfonic acid. (5) Solvent: Butyl carbitol acetate acetate and a higher alcohol having 13 to 15 carbon atoms (1: 1 mixed solvent of tridecanol and pentadecanol) were used.

The above component materials were taken so as to have the respective compounding ratios shown in Examples 1 to 4 of Table 1, then sufficiently stirred and mixed, and kneaded with a three-roll to form a conductive paste composition. It was made. [Production of translucent electromagnetic wave shield member] As a transparent substrate,
100 μm thick transparent polyethylene terephthalate (P
ET) film was used. In the case of forming the electromagnetic wave shield pattern portion by the intaglio offset printing method, the intaglio made of soda lime glass having a predetermined pattern was used. The intaglio has a line width of the printed matter of 25 μm and a line spacing of 225 μm (aperture ratio 81%, Sk / Ss = 4.3).
The shape of the recess was set so that

The silicone rubber on the outermost layer of the blanket is
An addition-type RTV silicone rubber having a JIS-A hardness of 40 degrees (10-point average surface roughness of 0.3 μm) was used. A flat plate intaglio offset printer (manufactured by Sumitomo Rubber Industries, Ltd.) using the silicone blanket and the intaglio was prepared on the transparent substrate using the conductive paste compositions prepared in Examples 1 to 4 and shown in Table 1. After printing a grid pattern with square hits with a line spacing and a film thickness of 250 μm, in a clean oven at 30 ° C. at 30 ° C.
Heat cured for a minute.

[Evaluation method] Measurement of specific resistance of conductive paste Volume resistance: Measured by a four-probe four-needle method using a Loresta manufactured by Mitsubishi Chemical. Sheet resistance: Shape is about 4mm x 50
A coating film of mm × 2.0 μm was prepared, and the above probe was applied to the central portion of the coating film to measure the resistance. Measurement of electromagnetic wave shielding effect It was measured using KEC of Kansai Electronics Industry Promotion Center. The measurement frequency was evaluated by the attenuation rate at 1 GHz using the measurement of the shielding rate in the range of 1 MHz to 1 GHz as an index.

Evaluation Criteria XX 0 to 20 dB X 20 to 30 dB Δ 30 to 40 dB ◯ 40 to 60 dB ◎ 60 to dB Visual Evaluation Evaluation Criterion × There is unevenness throughout, and unevenness occurs at the viewing angle.

Δ There is slight unevenness. ○ There is no unevenness and it is uniform. Visibility evaluation It was attached to the front surface of the PDP panel and visually evaluated according to the following criteria.

Evaluation Criteria x The screen became very dark. △ The screen became slightly dark. ○ The screen did not get too dark. Manufacturing cost The cost of the method using the intaglio offset printing method is set to 1, and the cost ratio is shown when compared with this.

Table 1 shows the evaluation results of the electroconductive pastes prepared in Examples 1 to 4 and the translucent electromagnetic wave shield member produced by using the electroconductive paste.

[0050]

[Table 1]

As shown in the results of Table 1 above, the electromagnetic wave shielding members produced in Examples 1 to 4 should satisfy all the evaluation results of visual evaluation, light transmission / visibility, and electromagnetic wave shielding property. Met. Comparative Examples 1 to 3 In the formulation shown in Example 1 above, when neither palladium nor platinum powder was added (Comparative Example 1), when the amount of palladium powder added was too small (Comparative Example 2) and when palladium powder was added. When the added amount was too large (Comparative Example 3), a conductive paste composition (Table 2) was prepared in the same manner as in Example 1 except that the composition was used to prepare an electromagnetic wave shielding member in the same manner. The evaluation results are shown in Table 2.

[0052]

[Table 2]

As a result, as shown in Table 2, the paste compositions of Comparative Examples 1 to 3 all have a large specific resistance, and the electromagnetic wave shielding members produced using these compositions are inferior in electromagnetic wave shielding property. It was Comparative Example 4 A mixed solution of a polyvinyl butyrate resin and a palladium catalyst was applied to the entire surface of a PET film, and electroless plating was performed.
An etching resist is applied on the copper foil, exposed, and developed to form a resist pattern in a grid pattern, and the copper foil in the non-image area is removed by etching using ferric chloride.
Finally, the resist was peeled off to prepare an electromagnetic wave shield member. The evaluation results are shown in Table 3. As a result, according to this method, a sufficiently good shield material can be obtained in terms of performance,
Since the number of manufacturing steps is large, the manufacturing cost was 3 to 10 times that of the case of Example 1.

Comparative Example 5 The same conductive paste composition as in Example 1 was used for screen printing to obtain a line width of 50 μm and a line spacing of 250.
An attempt was made to form a grid pattern of μm, but the line shape had many irregularities and many broken portions. Table 3
As shown in the results of 1., none of the evaluation results was satisfactory.

Comparative Example 6 An electromagnetic wave shield member was manufactured in the same manner as in Example 1 except that the same conductive paste composition as in Example 1 was used and the line width of the pattern was 3 μm. As a result, the obtained panel was inferior in electromagnetic wave shielding property (Table 3). Comparative Example 7 An electromagnetic wave shield member was produced in the same manner as in Example 1 except that the same conductive paste composition as in Example 1 was used and the pattern line width was 70 μm. As a result, the obtained panel was inferior in translucency and visibility (Table 3).

Comparative Example 8 An electromagnetic wave shield member was produced in the same manner as in Example 1 except that the same conductive paste composition as in Example 1 was used and the pattern film thickness was 0.3 μm. as a result,
The obtained panel was inferior in electromagnetic wave shielding properties (Table 3). Comparative Example 9 An electromagnetic wave shield member was produced in the same manner as in Example 1 except that the conductive paste composition similar to that in Example 1 was used and the pattern film thickness was set to 60 μm. As a result, the obtained panel was inferior in translucency and visibility (Table 3).

Comparative Example 10 An electromagnetic wave shield member was produced in the same manner as in Example 1 except that the pattern was changed to Sk / Ss = 0.5 using the same conductive paste composition as in Example 1. As a result, the obtained panel was inferior in translucency and visibility (Table 3). Comparative Example 11 Example 1 was repeated except that the same conductive paste composition as in Example 1 was used and the pattern was set to Sk / Ss = 10.
An electromagnetic wave shield member was produced in the same manner as in. As a result, the obtained panel was extremely inferior in electromagnetic wave shielding property (Table 3).

[0058]

[Table 3]

[Brief description of drawings]

1A) is a perspective view showing a translucent electromagnetic shield member (pattern), and FIG. 1B is an enlarged sectional view of a portion AA thereof.

FIG. 2 is a schematic view showing an example of a striped pattern.

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

FIG. 4 is a schematic diagram showing another example of a grid pattern.

5 (a) to 5 (c) are schematic views showing an example of a pattern made of a geometric pattern.

[Explanation of symbols]

1 Translucent electrode shield member (pattern) 2 transparent substrate 10 Electromagnetic shield pattern section 11 striped patterns 12 grid pattern 13 grid pattern WS line width Wk line spacing Wt film thickness

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-9-330667 (JP, A) JP-A-1-315903 (JP, A) JP-A-10-75087 (JP, A) JP-A-8- 99476 (JP, A) JP-A-4-363247 (JP, A) JP-A-10-162647 (JP, A) JP-A-2000-299592 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) H05K 9/00

Claims (3)

(57) [Claims] 1. An electromagnetic wave shield member having a pattern formed by printing a conductive paste containing a metal powder on the surface of a transparent substrate, wherein the metal powder is (a) silver or copper.
One or more selected from the group of copper powder coated with silver or silver
Of flake-shaped metal powder of (b) and either spherical powder of (b) palladium or platinum and having a weight ratio of (a) / (b) of 99.9 / 0.1-50 / 50. The total area (Ss) of the region where the shield pattern is formed and the total area (Sk) of the region where the shield pattern is not formed satisfy 1 ≦ Sk / Ss ≦ 9 and the line width Ws of the shield pattern. Is 5-40 μm and film thickness W
A translucent electromagnetic wave shield member, wherein t is 0.5 to 50 μm. 2. When forming a transparent electromagnetic wave shield pattern on the surface of a transparent substrate by an intaglio printing method using a blanket having ink releasability, (1) forming a shield pattern, (a) silver, There is copper
One or more selected from the group of copper powder coated with silver or silver
Of the scaly metal powder of (b) and spherical powder of (b) palladium or platinum, and the weight ratio of (a) / (b) is 99.9 / 0.1-50 / 50. (2) The line width of the pattern is 5 to 40 μm, and the film thickness is 0.5 to
50 μm, and (3) the relationship between the total area (Ss) of the area printed with the electromagnetic wave shield pattern printed on the surface of the transparent substrate and the total area (Sk) of the area not formed with the electromagnetic wave shield pattern. Formula (1): 1 ≦ Sk / Ss ≦ 9 (1) A pattern is formed so as to satisfy, and then a method of manufacturing a transparent electromagnetic wave shield member is characterized by curing. 3. The method for producing a translucent electromagnetic wave shield member according to claim 2, wherein the blanket has a surface rubber made of silicone rubber.