JPH11243296A - Transparent electromagnetic shield member and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent electromagnetic shield member which is superior in electromagnetic shielding and transparency and possessed of a reticulate conductive pattern that is high in visibility and a manufacturing method thereof. SOLUTION: A transparent member is formed in a manner where a copper thin-film layer 2 (100 to 2,000 Å) where a reticulate conductive pattern is provided through sputtering and a copper thick film layer 4 (1 to 10 μm) formed by plating are successively laminated on a transparent base 1 so as to be more than 50% in total light tansmittance Tt , wherein the reticulate conductive pattern is set lower than 200 m>/square in electrical resistance. Furthermore, the surface of the conductive pattern is colored brown to black with copper oxide and copper sulfide. The transparent member is formed in a manner where a copper thin film layer is formed on a polyethylene terephthalate(PET) base, then a reticulate pattern is exposed through a photolithography method, the exposed pattern is electroplated with copper, a residual resist 3 on a non- patterned part is removed, and the copper thin-film layer on a non-patterned part is removed by chemically etching the entire surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved transparent member for shielding electromagnetic waves and a method for manufacturing the same. The member is effective for shielding electromagnetic waves from electronic information equipment such as a plasma display.

[0002]

2. Description of the Related Art Electromagnetic waves emitted from various electronic information devices and, conversely, electromagnetic waves received from other worlds have become a problem as factors that cause malfunctions of the devices.

Various measures have already been proposed and implemented as measures to prevent equipment failures due to electromagnetic waves. For example, as an electronic information device, a CRT
In a plasma display monitor, in particular, an electromagnetic wave emitted from the inside of the monitor through the screen becomes an obstacle. Therefore, a method of loading an electromagnetic wave shielding material on the screen is generally adopted. In such a case, the shielding material must not be opaque at first, but must be transparent and effectively shield electromagnetic waves.

As the electromagnetic wave shielding material which does not lose its transparency, firstly, a material in which a conductive mesh fabric is bonded to a transparent sheet, or a material in which a transparent sheet is printed in a grid pattern by using a conductive ink have been proposed. However, in these things, transparency and electromagnetic wave shielding are incompatible,
On the other hand, if the transparency is to be increased, the electromagnetic wave shielding property is reduced. Therefore, with the intention of improving this, a sheet obtained by laminating a copper foil (or plate) on a transparent sheet, or a copper layer provided by electroless plating copper on the sheet, and after forming a mesh-like pattern, There has been proposed a shield material in which a non-mesh pattern portion is chemically etched with a ferric chloride aqueous solution or the like and removed by etching to form a copper mesh pattern on the sheet. For example, Japanese Utility Model Laid-Open Publication No. 64-44697 and Japanese Patent Laid-Open No. 5-283.
No. 889 can be mentioned.

[0005]

However, the above publications are not sufficiently satisfactory in the following points. In other words, in the case of copper foil, it is necessary to first provide an adhesive layer with an adhesive between the transparent sheet, but it is almost impossible to completely reduce the transparency due to this adhesive layer, Especially in the case of a mesh pattern with an unnecessarily thick layer of copper foil, there is a very high risk of peeling even with slight bending, and for the required electromagnetic shielding effect, copper foil is an unnecessarily thick layer. However, this thick layer makes it easy to perform side etching for chemical etching for producing a conductive pattern. As a result, it is difficult to obtain the pattern according to the initially set mesh pattern, and the line width is reduced. Irrespective of width or thickness, unevenness is likely to occur, and it is difficult to always obtain stable quality.

On the other hand, also in the case of electroless plating of copper, the transparent sheet is not directly plated, but a transparent anchor layer is first provided on the sheet, and the plating is performed thereon. The anchor layer is made of a polymer having fine pores or an inorganic compound. However, the existence of the anchor layer whatever the anchor layer inevitably reduces the overall transparency as described above. Further, since the mesh pattern is formed via the anchor layer, the adhesive strength of the transparent sheet is limited, and is not sufficient particularly for bending. Further, before the plating, pre-treatment generally performed conventionally (such as surface activation with a palladium catalyst) is required,
In addition, the production efficiency is poor as well as the management in production.

SUMMARY OF THE INVENTION The present invention is directed to a transparent member for electromagnetic wave shielding which does not conflict with the transparency and electromagnetic wave shielding properties directly without the use of an adhesive or the like. In order to find a means that can also be manufactured quickly, a sharp study has been made.

[0008]

That is, the present invention provides a transparent member for shielding electromagnetic waves and a method for manufacturing the same. First, the transparent member is described in claims 1 and 2 and the method for manufacturing the transparent member. Are described in claims 9 and 10, respectively. Claims 2 to 8 are provided as inventions dependent on claim 1 or 2.

Therefore, first, claim 1 which is the basis of the present invention.
Then, on the transparent substrate (1), the mesh conductive pattern is formed of a copper or alloy thin film layer (2) by a physical thin film forming means and a copper thickness by a plating means such that the total light transmittance is 50% or more. The conductive pattern is formed by sequentially laminating with the film layer (4), and the electric resistance value of the conductive pattern is 200 mΩ / □.
Provided is a transparent member for electromagnetic wave shielding described below.

According to a second aspect of the present invention, in order to provide visibility to the first aspect, a transparent member for electromagnetic wave shielding, in which a brown to black colored layer (5) is provided on the copper thick film layer (4), is provided. provide.

[0011] Claim 9 corresponds to claim 1,
The manufacturing method comprises sequentially performing the following steps (a) to (e). (B) A first step of forming a thin film layer having a thickness of 100 to 2000 mm on one surface of a sheet-like thermoplastic resin having a total light transmittance of 60% or more by sputtering copper or an alloy thereof. (B) A second step of developing the thin film layer by a photolithography method to expose a mesh pattern. (C) A third step in which copper is electrolytically plated on the mesh pattern to form a copper thick film layer having a thickness of 1 to 10 μm. (D) Next, a fourth step of removing and removing the remaining resist in the non-mesh pattern portion. (E) Finally, the entire surface is chemically etched to dissolve and remove the copper or its alloy thin film layer in the non-mesh pattern portion, and the copper or its alloy thin film layer is formed by sputtering and the copper thick film layer is formed by electrolytic plating. The fifth step of obtaining a mesh conductive pattern.

According to a tenth aspect, there is provided a manufacturing method corresponding to the second aspect. After performing the steps (a) to (e) described in the ninth aspect, the method further proceeds to the next (f). The sixth step described is performed to obtain a transparent member for electromagnetic wave shielding with improved visibility. (F) A sixth step of oxidizing or sulfurizing the copper surface of the mesh conductive pattern obtained in (e) to form a brown to black copper oxide or copper sulfide surface layer. Incidentally, the manufacturing method described in claims 9 and 10 corresponds to claim 1 or 2
The present invention is provided as one preferred embodiment of the transparent member for electromagnetic wave shielding described in (1), and is not limited only to this manufacturing method. The details will be described below in order.

[0013]

First, in claim 1 or 2,
The transparent substrate (1) is basically provided on the premise that at least a display screen or the inside of the device can be seen through the transparent member for shielding electromagnetic waves of the present invention, and preferably has a transmittance of 65% or more of the total light transmittance. In addition, it is preferable to have excellent heat resistance, weather resistance, non-shrinkage, mechanical strength, chemical resistance and the like. The shape is generally sheet-like (about 0.05 to 2 mm in thickness)
However, depending on the place of use, it may be bent. Specifically, a transparent substrate made of an inorganic substance such as a glass plate, polymethyl methacrylate, a copolymer of polystyrene or styrene with acrylonitrile or methyl methacrylate, poly (4-methylpentene-
1), an amorphous cyclic olefin polymer, such as polypropylene or cyclopentene, norbornene, tetracyclododecane, etc., alone or copolymerized with ethylene or the like, polyethylene terephthalate, polyethylene naphthalate, polyarylate, polyether sulfone, polycarbonate, Examples thereof include transparent thermoplastic substrates such as various liquid crystal polymers and transparent substrates made of acrylic, urethane, epoxy and silicone thermosetting transparent resins.

The choice of the transparent substrate is determined in consideration of various conditions, but the transparency (total light transmittance) is 6%.
It is desirable to select from a substrate made of a thermoplastic resin having 5% or more, preferably 85% or more. still,
The total light transmittance (hereinafter referred to as Tt) in the present invention is JT
It is a value (%) measured by a turbidity meter type NDH-20D manufactured by Nippon Denshoku Industries Co., Ltd. manufactured based on IS K7105 (1981). The larger this value is, the more transparent and excellent the visibility is. Will be.

Further, the mesh of the conductive pattern is
For example, a grid is formed by the same width or different width, and the opening part is not only a quadrangle but also a state crossing obliquely at a certain angle, that is, a case where the opening part is a rhombus, or about a pentadecagonal. It is not specified because the polygonal shape, that is, the opening may be a pentagonal to pentagonal shape. Note that it is necessary to determine what to do with the mesh, that is, what kind of aperture the mesh has, based on the assumption that both Tt and the electromagnetic wave shielding effect are high. Tt as a transparent member for electromagnetic wave shielding obtained is 50% or more, preferably 60%
Since it is more preferably 65% or more, it is necessary to determine it based on this.

The physical thin film forming means is generally called or practically used metal or nonmetal, especially in the case of thin film forming technology, chemical thin film forming means (plating method or C
VD method), specifically, there are three methods: a sputtering method, a vacuum deposition method, and an ion plating method. These are commonly used to convert the metal or nonmetal into a gaseous or ionic state by some method, receive it on the surface of a transparent substrate, and deposit it into a thin film. Use copper or its alloy.

Among the above physical means, a sputtering method or an ion plating method is preferable. Among them, the sputtering method is more preferable. This is because the ion plating method is vapor deposition with higher energy than the sputtering method, and the vapor deposition efficiency (speed) is accordingly high. However, because the temperature of the vapor deposition atmosphere is high, the selection of the transparent substrate is not limited, and the sputtering method is more preferable overall.

The sputtering method, the ion plating method, and the vacuum deposition method are methods generally used and have no special conditions.

The copper or its alloy formed by the thin film forming means is preferably pure copper as much as possible for copper, and its alloy is mainly made of copper, for example, Cu / Zn (brass), Cu / Sn (bronze), Cu
/ Al, Cu / Ni, Cu / Pd, phosphor bronze, Cu / B
alloys such as e. It should be noted that whether copper or an alloy thereof is used, the presence of a metal that is insoluble in an inorganic acid aqueous solution used for chemical etching should be avoided.

The means of plating with copper refers to either electrolytic plating or electroless plating, with electrolytic plating being more preferred. This is because a copper thick film layer having a required thickness can be stacked more quickly than electroless plating.

The present invention is configured by using the above means for the following reasons. First, the mesh conductive pattern formed on the transparent substrate is specified mainly by copper,
This is because it is easy to produce a shielding material having higher adhesion to the substrate and higher transparency and electromagnetic shielding properties than other metals. This means that a thin film is first deposited on the surface of the substrate by means of a physical thin film forming means such as sputtering. By adopting such means, it is possible to obtain a direct and extremely high adhesion without intervening a conventional pretreatment or a special adhesive. In addition, since the thin film in the non-patterned portion is easily and completely removed by the chemical etching for forming the conductive pattern, this has no effect on the transparency.

The presence of the thin film layer made of copper or an alloy thereof significantly improves the next means of laminating on the layer, that is, plating means, particularly, applicability of copper plating by electrolytic plating. , And the copper thick film layer can be formed directly and with extremely strong adhesion. Here, in particular, since plating means is employed, the thickness of copper required for imparting excellent electromagnetic wave shielding properties can be freely and easily and quickly obtained.

In the case of lamination by the above two means, the line width often observed by chemical etching for forming a conductive pattern is reduced (lack of reproducibility in one body). Substantially no side etching phenomenon can be achieved and a desired mesh conductive pattern can be reproduced, so that a mesh having a smaller line width can be obtained with a lower electric resistance value. That is, higher transparency and electromagnetic wave shielding properties can be obtained.

Copper or alloy thin film layer (2) corresponding to first layer
Is provided for forming a copper thick film layer (4) by plating.
In the copper thick layer corresponding to the layer. Therefore, it is preferable that the film thickness of the thin film layer (2) is made as thin as possible, and conversely, the second copper thick film layer is made thicker.

With respect to the thickness of each of the layers, it is preferred that the first layer be thinner and the second layer be thicker, but there are reasonable thicknesses as follows. That is, the thin film layer (2) made of copper or its alloy to be the first layer has a thickness of about 100 to
The thickness is 2,000 °, preferably 300 to 1700 °, and the thickness of the copper thick film layer (4) as the second layer is about 1 to 10 μm, preferably 2 to 8 μm. This is because, if the first layer is too thin, the copper thick film layer formed by plating the second layer has a high electric resistance value, so that it is impossible to perform speedy plating (in particular, electrolytic plating). On the other hand, if the thickness is too large, the removal time of the non-pattern portion in the chemical etching performed for forming the conductive pattern becomes longer, which results in a side etching phenomenon,
This is due to the fact that the line width of the conductive pattern tends to be thin, and the line is not faithfully reproduced. On the other hand, the second
The layers do not shield the required electromagnetic waves in the thinner direction. Conversely, if the thickness is too large, it is more than necessary and the electromagnetic wave shielding effect will not be further improved.

The conductive pattern is formed by laminating the first layer and the second layer, and further has an electric resistance value of the pattern itself, here, an electric resistance value per unit area, that is, a surface resistance value of 200 mΩ. / □ or less, preferably 5 to 150 mΩ / □, more preferably 5 to 50 mΩ / □. This electric resistance value is specified as described above because it is a very important factor for obtaining the required electromagnetic wave shielding property. However, here, the electric resistance value exceeds 200 mΩ / □. This is not good because the electromagnetic wave shielding effect is small and lacks practicality. On the other hand, as for the lower limit, the closer to 0 mΩ / □, the better. However, for this lower limit, transparency, ie, Tt
Becomes small, so that it is not preferable to make it too small.
It is better to aim at more than mΩ / □.

As described above, since the electric resistance directly appears as an electromagnetic wave shielding effect, the smaller the resistance, the better, but the Tt generally decreases. It is required to maximize the transparency Tt and maximize the electromagnetic wave shielding effect. To this end, it is conceivable that the line width and pitch interval of the conductive pattern to be formed are made as small as possible, and the thickness of copper forming the pattern is further increased. This is also possible in the configuration of the present invention, and it can be said that this is also a revolutionary invention. Note that the electrical resistance value referred to in the present invention is obtained by measuring the copper mesh conductive pattern of the obtained mesh with LORESTA (Loresta, trade name: MCP, manufactured by Mitsubishi Yuka Co., Ltd.).
−TESTERFP) and a dedicated MCP probe (measured by four terminals) connected to the copper surface of the pattern, and the four terminals were firmly brought into contact with the copper surface of the pattern, and the measurement was performed at different locations.

Further, the brown to black colored layer (5) according to the second aspect is more easily viewed when the display screen is viewed through the finally obtained transparent member for electromagnetic wave shielding and can be stared for a longer time. Characteristics that do not feel tired much in the eyes,
That is, it is provided to improve the visibility. This characteristic varies depending on the color, and is generally brown to black, and is more preferably closer to black than pure brown.

The coloring layer (5) is provided on the copper surface and its type is not specified, but it is preferable that the coloring layer (5) be as thin as possible and firmly adhere to the copper surface. In this sense, it is preferable to use copper oxide or copper sulfide, and it is also preferable that the surface of the copper be oxidized or sulfidized to change the surface layer to copper oxide or copper sulfide to form a colored layer.

Next, a manufacturing method according to claims 9 and 10 will be described. First, a method for manufacturing a transparent member for electromagnetic wave shielding according to claim 1 will be exemplified in claim 9, because this is a means for achieving the object of the present invention more effectively. .

First, in the first step (a),
As the transparent substrate (1), the sheet-like thermoplastic resin having at least 65% or more of Tt of the transparent substrate (1) is used. Among them, sheets of polyethylene terephthalate, polyethylene naphthalate, and amorphous polyolefin are preferable.
The thickness of the sheet is preferably about 0.1 to 1 mm in view of handleability and the Tt. Then, copper or an alloy thereof is targeted on one surface of the sheet by sputtering to a thickness of 100 mm.
Sputter-deposited into a thin film of up to 2000 °. In this sputtering, the sheet does not need to be subjected to any pretreatment, and can be immediately performed.However, in some cases, the surface may be subjected to pretreatment such as degreasing and washing or glow or corona discharge treatment. is there. The sputtering may be performed under general conditions, but is preferably performed under the following conditions. That is, 10 ^-1 to 10 ^-2
This is a low gas pressure sputtering performed under a low gas pressure of not more than Torr (the gas is an inert gas such as argon). This low gas pressure sputtering is a tripolar glow discharge, a dipolar glow R
This corresponds to sputtering by F discharge, magnetron, or ion beam, but sputtering by magnetron is more preferable. This is because the speed of the formed thin film is high, the purity is high, and the temperature generated in the vacuum chamber of the sputtering apparatus is low (at most around 100 ° C.).

Next, in the second step (b), the thin film layer of copper or its alloy obtained in the above step is developed by photolithography to expose a desired mesh pattern. Here, the photolithography method generally involves the application of a photosensitive resist → vacuum adhesion of a masking film → exposure → development for dissolving and removing exposed or unexposed portions → exposure of a desired mesh pattern. Say. Here, the photosensitive resist is classified into a negative type and a positive type. In the case of the negative type, when exposed to ultraviolet rays, only that portion is photo-cured.
The positive type has the opposite light characteristics to the negative type, and the portion that has received ultraviolet light is photolyzed. If both development processes are performed,
Unexposed portions are dissolved and removed, and in the positive type, exposed portions are dissolved and removed. Therefore, as the masking film, a positive film is used for the negative type (the mesh pattern is black), and a negative film is used for the positive type (the mesh pattern is transparent).

The photosensitive resist is not specified, but generally, an acrylic type is used for a negative type and a diazo type is used for a body type. Since the resist is generally in a liquid state, it is applied by a method of applying the resist. However, the resist may be in the form of a film, such as a dry film. When the content of the mesh pattern, particularly a pattern that is not a fine pattern, is desired, the mesh pattern can be directly exposed on the thin film layer by a printing method instead of the photolithography method. it can.

Next, in the third step (c), copper is electrolytically plated on the thin film layer of the exposed mesh pattern portion up to the previous step, based on the thin film layer, and the thickness is 1 to 10 μm. Laminate copper. The conditions for the electrolytic plating may be in accordance with the commonly used copper plating. For example, when using a copper sulfate plating bath adjusted to contain copper sulfate and sulfuric acid as main components, the thin film-forming thermoplastic resin sheet is immersed in the copper-containing plating bath as an anode, and the cathode current density is adjusted to 0.1%. 5-6 A / dm ² , the solution temperature 15-30 ° C.,
The plating is performed at a plating rate of 0.1 to 1.2 μm / min. Of course,
Other methods, for example, copper plating with a plating bath containing cuprous cyanide and sodium cyanide as main components, that is, copper cyanide plating, or copper plating with a plating bath containing copper pyrophosphate and potassium pyrophosphate as main components, That is, copper pyrophosphate plating may be used.

Next, in the fourth step (d), the photosensitive resist layer in the non-mesh pattern portion remaining without being exposed in the above step is removed. The peeling removal is generally performed by spraying or rocking immersion using a stripping chemical solution of various organic solvents or alkaline aqueous solutions.

The last step (e), which is the fifth step, is to chemically etch the entire surface at the same time, and the chemical etching time is at least that of the copper or alloy thin film layer in the non-reticulated pattern portion. Until dissolved and removed. Therefore, the time depends on the thickness of the thin film layer. Since the entire surface is chemically etched at the same time,
The thickness of the layer by the copper electroplating in the third step corresponds to the thickness of the thin film layer, and is thinned by chemical etching. However, compared with the thickness of the thin film layer (100 to 2000 °), The thick copper layer by plating is much thicker (1
-10 μm), there is no substantial change in the electric resistance value.

Here, the chemical etching is an operation of chemically dissolving and removing copper or its alloy with an etching solution. Therefore, the etchant is not limited as long as the copper or its alloy is dissolved. Generally, it is an aqueous solution of ferric chloride or cupric chloride which is usually used, but it is preferable to use an aqueous solution of sulfuric acid / hydrogen peroxide or the like which can be etched milder than these. This is because if the chemical etching here simply removes the very thin layer of sputtered copper or its alloy in the non-meshed pattern, the desired conductive pattern will form itself. In other words, this is different from the case where a conductive pattern is formed by chemically etching a thick copper layer. The chemical etching time is completed in a short time of about 20 to 50 seconds, but immediately after the completion, it is washed with water and dried to complete the entire process.

Next, the sixth step (f) according to claim 10 will be described. In the sixth step, when only the copper color of the copper conductive pattern obtained in claim 9 lacks visibility as described above, the surface of the conductive pattern is colored with a different color. This is a step performed for improvement.
Here, since it is preferable that the different color is changed from brown to black, this is performed with copper oxide or copper sulfide. This coloring with copper oxide makes the conductive pattern come into contact with an oxidizing agent to chemically oxidize the copper surface to form a surface layer of copper oxide.
On the other hand, coloring with copper sulfide is performed by contact with a sulfurizing agent. Therefore, unlike the method of providing a new coloring layer by coating or the like with a different kind of material, the coloring is performed by such a chemical method. Not even.

There are various oxidizing agents, but an aqueous solution of an alkaline strong oxidizing agent is preferred. For example, there is an aqueous solution in which sodium chlorite has been made alkaline with sodium hydroxide, and it is only necessary to immerse the aqueous solution, and the immersion time may be several minutes. By changing the sodium hydroxide concentration, sodium chlorite concentration, immersion time, etc. in the aqueous solution, it is thought to be derived from the crystal structure of the generated copper oxide, but the color can be freely changed from brown to black. Can be. The sulfurizing agent is, for example, an aqueous solution containing sulfur or an inorganic compound thereof (eg, potassium sulfide) as a main component. Here, in the case of sulfur, since it is not efficient by itself, quick lime, casein and, if necessary, potassium sulfide as an auxiliary agent are added to form an aqueous solution. On the other hand, in the case of potassium sulfide, an aqueous solution is formed using ammonium chloride or the like in combination to promote the reaction.
The touching time, temperature, etc. may be appropriately determined by experiment in any case. The thickness of the surface layer made of copper oxide varies depending on the oxidation or sulfidation time, but it is necessary to make the electric resistance not more than 200 mΩ / □ by increasing the thickness.

FIG. 1 further shows the structure of the structure obtained by processing in each of the steps (a) to (f). The figure shows a part of the structure in cross section. In this figure, 1 is a sheet-like thermoplastic resin having a Tt of 65% or more, 2 is a thin film layer obtained by sputtering copper or an alloy thereof,
2a is a portion where the mesh pattern is exposed by the lithography method, 3 is a portion where the photosensitive resist 3a coated on the entire surface is left, 4 is a copper thick film layer laminated on the exposed thin film layer by electrolytic plating, and 5 is an oxidized film. It is a copper surface layer. FIG. 2 is a perspective view of (f), and 6 is an opening, and Tt is increased or decreased depending on the total area of the opening.

In addition to the manufacturing method described above, for example, after copper sputtering and electrolytic plating are performed in advance, chemical etching is performed together with photolithography, or first, copper sputtering is performed to obtain the obtained copper. Chemical etching of the thin film layer together with photolithography,
The thin film is patterned. Next, copper may be electroplated, and only the pattern portion may be electroplated with copper and laminated. However, the manufacturing method according to claim 9 is preferable to these methods for the following reasons.

That is, the reason is faithful reproducibility especially for the original pattern. This reproducibility is nothing but a change in the line width of the pattern itself and no side etching. Therefore, it is possible to freely obtain an electric resistance value, that is, an electromagnetic wave shield as desired. The excellent reproducibility means that a thinner wire and a thicker copper layer can be stacked thereon. This means that to obtain the desired electrical resistance,
Instead of increasing the line width, it is possible to increase the thickness of the copper to be laminated with a smaller line width, so that even if the electromagnetic wave shielding property is increased, the decrease in the overall transparency can be kept extremely small. You can do it. That is, it is easier to improve the electromagnetic wave shielding property by lowering the electric resistance and also to improve the overall Tt than in other manufacturing methods.
In addition, the reproducibility of the conductive pattern was confirmed by the above-mentioned manufacturing method.
As described above, the test was performed with a pitch of 100 μm or more and a thickness of 10 μm or less. The value obtained by dividing 2.54 cm by the pitch is the mesh degree.

[0043]

Next, the above-mentioned manufacturing method will be described in more detail with reference to examples. In addition, the electromagnetic wave shielding effect (sex) referred to in the text and the example
Is based on the Kansai Electronics Industry Promotion Center Act (generally KEC
Frequency 1
It is expressed by the attenuation rate (dB-dB) of the electromagnetic wave measured in the range of 00 to 1000 MHz (megahertz).

Example 1 (Example corresponding to claim 9) Thickness 125 μm, size 400 × 1000 mm, Tt =
90% biaxially oriented polyethylene terephthalate (hereinafter P
Before the next sputtering was performed, first, glow discharge was performed to perform pretreatment. The PET film of this preprocessing in a vacuum chamber of a magnetron-type sputtering apparatus, and arranged to face the copper target, air argon fully purged vacuum of 2 × 10 ^-3 Torr obtained environment, the applied voltage Sputter deposition was repeated three times at 1 m / min at 9 kW DC.

The thickness of the copper thin film obtained above is 120
It was uniform at 0 ° (± 100 °). A part of the film was cut off and subjected to a tape peeling test, but there was no appearance that the copper thin film was peeled off.

Next, a positive resist was coated on the vapor-deposited surface of the obtained copper-deposited PET film by a roll coater to provide the resist layer having a thickness of 5 μm. Then, a line width of 15 μm and a pitch of 150 μm are formed on the surface of the resist layer.
A negative film depicting a m-shaped mesh pattern (mesh degree = 170) (masking film depicted in a mesh with a transparent pattern portion and a black non-pattern portion) was exposed in vacuum and then exposed. (The light was irradiated at 130 mJ / cm ² using an ultra-high pressure mercury lamp as a light source.) By this exposure, the resist at the mesh pattern portion was
Since it was decomposed, this portion was dissolved and removed with a developing solution, and finally washed with water and dried. The resist in the non-pattern portion remains in close contact with the copper deposition surface. Therefore, the non-patterned portion is masked, and the patterned portion has the copper deposition layer exposed.

Next, copper was electrolytically plated on the exposed mesh pattern under the following conditions. That is, a mixture of copper sulfate, sulfuric acid, and water was used as a plating solution, the bath temperature was 23 ° C., the cathode current density was 1.7 A / dm ² , the plating rate was 0.
Electroplating was performed at 3 μm / min. Then, it was thoroughly washed with water and dried.

Next, while the acetone was sprayed on the whole surface of the electroplated product, the resist was brushed with a light touch to dissolve and remove the remaining resist in the non-pattern portion, washed with water, and dried. The obtained part was cut out, the cross section was enlarged under a microscope and observed, and the laminated copper plating layer had a very sharp prismatic shape, a width of 15.1 μm, and a thickness (height) of 4. It was 9 μm. Here, the reason why the copper plating layer was laminated very sharply in a prismatic shape was that a frame was formed in advance by a photoresist, and since this frame was formed accurately and sharply, copper was formed along this frame. It is considered that they were stacked.

Next, the copper-plated product was immersed in acetone to dissolve and remove the remaining non-pattern resist, washed with water and dried, and then etched entirely under the following conditions.

As a chemical etching solution, an aqueous solution containing sulfuric acid and hydrogen peroxide was used, placed in a bath, and etched with stirring. Etching time is 30
Seconds, water was washed and dried immediately after 30 seconds. PET
A sharp conductive pattern of 170 mesh was formed on the film, and even when bent at 180 °, there was no peeling at all. The line width of the formed conductive pattern was 15 μm, and the thickness was 4.8 μm. The pattern had a prismatic shape and no side etching was observed. Table 1 summarizes the electric resistance value, the electromagnetic wave attenuation rate, and the Tt.

[0051]

[Table 1]

(Embodiment 2) (Embodiment Corresponding to Claim 10) In the same manner as in Embodiment 1, except that the following conditions are changed, first, a mesh-shaped conductive pattern made of copper is made of a PET film through each step. Laminated on top.・ Thickness of thin film layer formed by copper sputtering is 1
700Å ・ Positive resist coating thickness is 7μm ・ Negative film pattern image is mesh pattern with line width 25μm / pitch 250μm (mesh degree = 101) ・ Copper electroplating thickness is 6.8μm ・ Chemical etching Time is 50 seconds

The thickness of the conductive pattern obtained above is:
The line width was 6.6 μm, the line width was 25.0 μm, there was no side etching, and the cross-sectional observation showed a sharp prismatic shape.

Next, in order to color the surface of the formed copper conductive pattern from brown to black, an aqueous solution containing sodium hydroxide and sodium chlorite was used as an oxidation bath at 70 ° C. for 5 minutes. Was immersed. After 5 minutes passed, it was taken out, washed and dried. The copper in the pattern turned black-brown and the thickness of the colored layer was about 0.52 μm. The electric resistance value, electromagnetic wave attenuation rate, and Tt are shown in Table 1.
Summarized in

Further, the obtained colored conductive pattern PE
When the T film was suspended on the screen of the plasma display at a distance of 10 mm and the image was viewed, the T film was easier to see than the uncolored product of Example 1 and could be visually recognized without eyestrain.

(Example 3) (Example corresponding to claim 10) First, a mesh-shaped conductive pattern made of laminated copper was formed on a PET film under the same conditions as in Example 2. Then, it is added to quick lime, casein and potassium sulfide, and dissolved in distilled water to prepare a sulfurization bath.
Indirect at 60C for 60 seconds. It was immediately taken out, washed and dried. The pattern surface was colored and was blacker and sharper than in Example 2. Of course, this pattern did not adversely affect the pattern.

(Comparative Example 1) (Electric resistance value was 200 mΩ /
Exceeding □) In Example 1, except that the following conditions were changed, the respective steps were sequentially performed under the same conditions to obtain a P having a conductive pattern for comparison.
An ET film was prepared.・ The pattern image of the off-negative film has a line width of 13 μm /
Mesh pattern with a pitch of 200 μm (mesh degree = 195) ・ Lamination thickness of 0.8 μm by electrolytic plating of copper

The line width of the copper conductive pattern on the obtained PET film is 10 to 12 μm, and the thickness of the copper is 0.6 to 0.5 μm.
It was not constant at 67 μm. About this variation,
It is considered that the line width of the mesh pattern and the thickness of the copper plating were too small, resulting in thinning by chemical etching and unevenness in the electrolytic plating of copper.

Table 1 summarizes the electrical resistance value, electromagnetic wave attenuation rate, and Tt of the obtained product.

The electromagnetic wave shielding transparent member according to the first or second aspect of the present invention can be used as it is. However, in consideration of the fact that the pattern is formed of copper and damage due to external force, etc. In use, it is preferable to provide a protective film on the entire surface. As for the choice of the protective film, it is a matter of course that the protective film has a strong adhesion, but it is considered that it has excellent transparency, barrier properties against moisture and oxygen, impact resistance, heat resistance, chemical resistance and the like. There is a need to. Specific examples include those based on acrylic, urethane-based, and silicone-based curable organic substances, and those based on inorganic compounds such as silicon dioxide. Incidentally, the protective film of silicon dioxide is more preferable than the above-mentioned organic type, which can be formed by sputtering silicon dioxide to physically form a protective film, but chemically coating, for example, a perhydropolysilazane solution, This can be decomposed into silicon dioxide by heating or adding water, or a silicon dioxide protective film can be formed by a sol-gel method using a polyfunctional alkoxysilane.

[0061]

The present invention is configured as described above, and has the following effects.

The transparent substrate and the conductive pattern of the copper mesh formed thereon are laminated via a copper (or alloy thereof) thin film layer formed directly by a technique such as sputtering. It has extremely high adhesion to the substrate. This resists bending and does not peel off even when used for a long time in high temperature and high humidity.

As described above, since the copper conductive pattern is formed directly without the use of an adhesive or the like as in the conventional case, there is no reduction in transparency.

Further, since the electric resistance of the conductive pattern required to obtain excellent electromagnetic wave shielding properties is formed by plating copper with a narrower width and a larger layer thickness, the electromagnetic wave shielding effect and the high transparency are obtained. It is a member which has.

Further, with respect to the method of manufacturing the transparent member for electromagnetic wave shielding of the present invention, by using the method according to the ninth aspect, there is no concern about thin side etching of the pattern, and the manufacturing can be easily performed with a high yield. Now you can do it.

Further, the surface layer of the mesh conductive pattern can be colored from brown to black with copper oxide or copper sulfide. Even at the gaze of the eyes, the feeling of eye fatigue is small.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one obtained in each of the manufacturing steps of claims 9 and 10.

FIG. 2 (f) is a perspective view.

[Explanation of symbols]

 1. 1. Sheet-like thermoplastic resin 2. Sputtered copper thin film layer 3. Residual photosensitive resist Copper plating layer 5. Copper oxide colored surface layer 6, opening

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C23C 26/00 C23C 26/00 F C25D 3/38 C25D 3/38 (72) Inventor Toshinori Okamoto 163 Morikawaramachi, Moriyama City, Shiga Prefecture Gunze Corporation Shiga Research Laboratory (72) Inventor Masanori Yamamoto 163 Morikawaramachi, Moriyama City, Shiga Prefecture Gunze Corporation Shio Research Laboratory

Claims (10)

[Claims] 1. A total light transmittance of 50 on a transparent substrate (1).
% Or more, the mesh conductive pattern is formed by sequentially laminating a copper or its alloy thin film layer (2) by a physical thin film forming means and a copper thick film layer (4) by a plating means, And the electric resistance value of the conductive pattern is 200 m
A transparent member for electromagnetic wave shielding, characterized by being Ω / □ or less. 2. The electromagnetic wave shielding transparent member according to claim 1, further comprising a brown to black colored layer (5) provided on the copper thick film layer (4). 3. The transparent substrate (1) has a total light transmittance of 65.
% Or more of the sheet-like thermoplastic resin. 4. The method according to claim 1, wherein said physical thin film forming means is a sputtering method or an ion plating method.
3. The transparent member for electromagnetic wave shielding according to item 1. 5. The transparent member for electromagnetic wave shielding according to claim 1, wherein the plating means is an electrolytic plating method. 6. The transparent member for electromagnetic wave shielding according to claim 1, wherein the thickness of the thin film layer (2) of copper or an alloy thereof is 100 to 2000 °. 7. The thick copper layer (4) has a thickness of 1 to 10 μm.
The transparent member for an electromagnetic wave shield according to claim 1, wherein m is m. 8. The transparent member for electromagnetic wave shielding according to claim 2, wherein the colored layer (5) is made of copper oxide or copper sulfide. 9. The method according to claim 1, wherein the steps (a) to (e) are sequentially performed. (A) A first step of forming a thin film layer having a thickness of 100 to 2000 mm on one side of a sheet-like thermoplastic resin having a total light transmittance of 65% or more by sputtering copper or an alloy thereof. (B) A second step of developing the thin film layer by a photolithography method to expose a mesh pattern. (C) A third step of laminating a copper thick film layer having a thickness of 1 to 10 μm by electroplating copper on the mesh pattern. (D) Next, a fourth step of removing and removing the remaining resist in the non-mesh pattern portion. (E) Finally, the entire surface is chemically etched to dissolve and remove the copper or its alloy thin film layer in the non-mesh pattern portion, and the copper or its alloy thin film layer is formed by sputtering and the copper thick film layer is formed by electrolytic plating. The fifth step of obtaining a mesh conductive pattern. 10. The method for manufacturing a transparent member for electromagnetic wave shielding according to claim 2, further comprising the following step (f). (F) A sixth step of oxidizing or sulfurizing the copper surface of the mesh conductive pattern obtained in (e) to form a brown to black copper oxide or copper sulfide surface layer.