JP2004241761A - Electromagnetic wave shielding sheet and method for manufacturing the same - Google Patents

Abstract

【Task】
Provided is a method of manufacturing an electromagnetic wave shielding sheet that shields electromagnetic waves and is excellent in brightness and mesh accuracy, and that can be manufactured in a short process with low yield, good yield, and low cost.
[Solution]
At least (a) a step of applying a conductive treatment layer to one surface of the transparent base material to prepare a metal-plated transparent base material by electrolytic plating; and (b) a metal plating layer of the metal-plated transparent base material; And a step of forming the conductive treatment layer into a mesh by a photolithography method, and a method of manufacturing the conductive processing layer, the method including no adhesive layer.
[Selection diagram] FIG.

Description

  The present invention relates to an electromagnetic wave shielding sheet for shielding (shielding) an electromagnetic wave generated from a display such as a CRT or a PDP. More specifically, the present invention relates to an electromagnetic wave shielding sheet having excellent transparency and mesh accuracy. The present invention relates to an inexpensive sheet for electromagnetic wave shielding, which has a small number of steps and a good yield in a short process, and a method for manufacturing the same.

  In the present specification, “ratio”, “part”, “%”, and the like indicating the composition are based on mass unless otherwise specified, and “/” indicates that they are integrally laminated. "PDP" is "plasma display element", "AR" is "anti-reflection", "AG" is "anti-glare", "NIR" is "near infrared", "EMI" is "electromagnetic wave", and " "PET" is "polyethylene terephthalate" and is an abbreviation, synonym, functional expression, common name, or industry term. Further, “anti-reflection” generally uses the “anti-reflection and / or anti-glare” function.

(Background of Technology) In recent years, with the advancement of functions and the increasing use of electric and electronic devices, electromagnetic noise interference (EMI) has increased, and electromagnetic waves have also been generated in displays such as CRTs and plasma display panels (PDPs). appear. A plasma display panel is a combination of glass having a data electrode and a fluorescent layer and glass having a transparent electrode, and when operated, generates a large amount of electromagnetic waves, near-infrared rays, and heat. Usually, a front plate including an electromagnetic wave shielding sheet is provided on the front surface of the plasma display panel to shield electromagnetic waves. The shielding property of the electromagnetic wave generated from the front surface of the display needs a function of 30 dB or more in 30 MHz to 1 GHz. Also, near-infrared rays having a wavelength of 800 to 1,100 nm generated from the front surface of the display may cause other devices such as VTRs to malfunction, and thus need to be shielded.
Furthermore, in order to make the display image on the display easier to see, the metal mesh (line portion) for shielding electromagnetic waves is difficult to see, and the mesh pattern accuracy is good and the mesh is not disturbed. , Visible light transmittance).
Furthermore, the plasma display panel is characterized by a large screen, and the size (external dimensions) of the electromagnetic wave shielding sheet is, for example, 621 × 831 mm for the 37-inch type, 983 × 583 mm for the 42-inch type, and there are even larger sizes. .
For this reason, the electromagnetic wave shielding sheet shields electromagnetic waves, is excellent in transparency and mesh accuracy, and has a low yield and good inexpensive electromagnetic wave shielding sheet in a short process in the manufacturing process with less warpage or air bubble mixing. Is required.

(Prior art) Conventionally, the following three methods are usually used for producing a sheet for electromagnetic wave shielding having a mesh-like metal layer.
(1) A method is known in which conductive ink is printed in a pattern on a transparent base material, and metal plating is performed on the conductive ink layer (see, for example, Patent Documents 1 and 2; JP-A-2000-13088). JP-A-2000-59079). However, the pattern formed by printing has poor accuracy, and the mesh metal-plated on the pattern has a poor appearance, and the display image is inferior in visibility, so that it is practically used as an electromagnetic wave shielding sheet for a high-definition display. Can not be used.
(2) A method is known in which a conductive ink or a photosensitive coating solution containing a chemical plating catalyst is applied to the entire surface of a transparent base material, the coating layer is formed into a mesh by photolithography, and then metal plating is performed on the mesh. (For example, see Non-Patent Documents 1 and 2). However, although the pattern accuracy of the mesh is good, there is a disadvantage that it is difficult to maintain uniformity of the plating thickness because plating is performed after the pattern. Further, in the manufacturing process, since the resistance of the conductive ink is high, there is a problem that plating time is long and productivity is low.
(3) A method of laminating a transparent substrate and a metal foil with an adhesive and then forming the metal foil into a mesh shape by a photolithography method is known (for example, see Patent Documents 3 and 4). However, although the pattern accuracy of the mesh is good, warpage is likely to occur because different materials are laminated. In addition, since the roughness of the metal foil is transferred to the surface of the adhesive in the mesh opening and remains in an uneven shape, light is irregularly reflected by the roughness, and the transparency of the mesh opening is poor. There is. Further, in the manufacturing process, there is a possibility that wrinkles or bubbles may be mixed due to lamination using an adhesive. Further, since the surface of the adhesive in the mesh opening is made transparent by filling the roughness thereof, there is a problem that one additional step is required as a transparentizing step.

JP-A-2000-13088 JP 2000-59079 A JP-A-11-145678 JP-A-10-41682 Sumitomo Osaka Cement Co., Ltd. New Materials Division, New Materials Research Laboratories, New Materials Research Group, “Photo-Resolution Chemical Plating Catalyst”, [online], date not listed, Sumitomo Osaka Cement Co., Ltd., On March 7], the Internet <URL: http: // www. socnb. com / product / hproduct / display. html> Sumitomo Osaka Cement Co., Ltd. New Materials Research Division, New Materials Research Laboratory, New Materials Research Group, “Metal Fine Pattern Forming Materials”, [online], date not listed, Sumitomo Osaka Cement Co., Ltd., [January 7, 2003 Date search], Internet <URL: http: // www. socnb. com / product / hproduct / display. html>

  Therefore, the present invention has been made to solve such a problem. The object is to provide an electromagnetic wave shielding sheet that is arranged on the front of a display such as a CRT or PDP to shield electromagnetic waves generated from the display, and that is excellent in transparency and mesh accuracy so that a display image can be viewed easily. It is to be. It is still another object of the present invention to provide a method of manufacturing an electromagnetic wave shielding sheet that can be manufactured in a short process with good yield and low cost, with less warpage or air bubble mixing in the manufacturing process.

To solve the above issues,
The method for producing an electromagnetic wave shielding sheet according to the invention of claim 1 is a method for producing an electromagnetic wave shielding sheet having a mesh-like metal layer on one surface of a transparent substrate, wherein at least (a) one of the transparent substrates A step of preparing a transparent substrate having a metal layer formed thereon as a metal plating layer by electroplating a conductive treatment layer on the surface of (a), and (b) forming a metal plating layer and a conductive layer on the metal-plated transparent substrate. And forming the treatment layer into a mesh by a photolithography method.
In the method for manufacturing an electromagnetic wave shielding sheet according to the second aspect of the present invention, the transparent substrate is glass, and the steps (a) and (b) are performed in a single-wafer state.
An electromagnetic wave shielding sheet according to a third aspect of the present invention is the electromagnetic wave shielding sheet having a mesh-like metal layer on one surface of a transparent substrate, wherein at least (a) a conductive treatment is applied to at least one surface of the transparent substrate. Providing a transparent substrate on which a metal layer is formed as a metal plating layer by electroplating, and (b) applying a metal plating layer and a conductive treatment layer of the metal plating transparent substrate to each other by photolithography. And a step of forming into a mesh by using the method described above.
An electromagnetic wave shielding sheet according to a fourth aspect of the invention has a blackening layer on at least one surface of the metal plating layer.
An electromagnetic wave shielding sheet according to a fifth aspect of the present invention has an anticorrosion layer on at least one surface of the metal plating layer or the blackening layer.
The electromagnetic wave shielding sheet according to the invention of claim 6, wherein at least the surface of the metal plating layer of the transparent substrate is mat-shaped, and the material of the transparent substrate is a polyester resin. is there.
In the electromagnetic wave shielding sheet according to the invention of claim 7, the material of the transparent base material is glass, and all the constituent materials are made of inorganic materials.

(Points of the Invention) The present inventors diligently studied and found that no adhesive was used and that the entire structure was made of inorganic material. Therefore, the present invention has been achieved by providing a conductive material layer mainly including a metal layer directly on a substrate. For this reason, excellent heat resistance, no adverse effects due to the adhesive, less warpage or mixing of air bubbles in the production process, a short process with good yield, and low cost production.
According to the first aspect of the present invention, there is little warpage or mixing of air bubbles in the manufacturing process, and the production can be performed at a good yield in a short process at low cost. In addition, since the metal layer is provided on the transparent substrate by the electrolytic plating method, the thickness of the metal layer is uniform, and a desired plating thickness can be obtained in a short time, so that the production efficiency is high, and in order to pattern after plating, Problems such as disconnection are unlikely to occur. Furthermore, since there is no adhesive layer at the mesh openings, the transparent base material is exposed and flat, and the transparency is good. Is provided.
According to the second aspect of the present invention, it is possible to easily perform processing at a high temperature in the preceding and subsequent steps, to reduce warpage and mixing of bubbles in the manufacturing process, and to manufacture an electromagnetic wave shielding sheet that can be manufactured in a single-wafer process with a high yield. A method is provided.
According to the third aspect of the present invention, since a conventional transparent substrate and a metal layer that are separately manufactured are not laminated, warpage (also referred to as curling) due to aging or aging due to a so-called bimetal effect is small. In addition, there are few wrinkles, warpages, bubbles, etc., which are likely to occur in the step of laminating with an adhesive.Furthermore, the mesh openings have no irregularities where the roughness of the conventional metal foil is transferred, and the mesh openings are transparent. Therefore, an electromagnetic wave shielding sheet that shields electromagnetic waves and allows a display image to be easily viewed is provided.
According to the fourth aspect of the present invention, there is provided an electromagnetic wave shielding sheet capable of displaying a display image with high contrast and good visibility since a line portion of a mesh is difficult to see.
According to the fifth aspect of the present invention, a highly durable electromagnetic wave shielding sheet is provided because the blackened layer is prevented from falling off and the mesh-like metal is hardly rusted.
According to the sixth aspect of the present invention, since reflection of external light is low and reflection can be reduced, the display quality of a display image is high, and further, the contrast can be increased by using the blackening layer in combination, so that good visibility can be achieved. An electromagnetic wave shielding sheet is provided.
According to the present invention of claim 7, the electrode plate is provided by providing an electrode on the back surface of the glass because the warpage and the inclusion of air bubbles are small, the yield is good in a short process, and the production is inexpensive. The present invention provides an electromagnetic wave shielding sheet capable of reducing the distortion of glass and performing high-temperature treatment.

If the electromagnetic wave shielding sheet 1 of the present invention is arranged on the front surface of a display such as a CRT or PDP, it shields electromagnetic waves generated from the display, has excellent transparency and mesh accuracy, and has a good appearance. Therefore, display quality such as brightness and contrast of the display image is high, and the display image can be viewed well.
In addition, the electromagnetic wave shielding sheet 1 of the present invention has a metal layer side flattened as necessary, and further has a light absorber layer that absorbs visible and / or near infrared rays of a specific wavelength as needed. It may be a front plate. When such a front panel is arranged on the front of the display, it can shield electromagnetic waves generated from the display, have appropriate transparency, and can easily view an image displayed on the display.
In the present specification, the electromagnetic wave shielding sheet of the present invention is mainly described for displays such as CRTs and PDPs, but it is needless to say that the sheet can be used for various types of electromagnetic waves other than displays.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view of the electromagnetic wave shielding sheet of the present invention.
FIG. 2 is a perspective view schematically showing a part of the electromagnetic wave shielding sheet of the present invention.
FIG. 3 is a sectional view taken along the line AA and a sectional view taken along the line BB of FIG.
FIG. 4 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. 2 after the blackening process.
FIG. 5 is a cross-sectional view of the electromagnetic wave shielding sheet showing one embodiment of the present invention.

(Overall Structure) As shown in FIG. 1, the electromagnetic wave shielding sheet 1 of the present invention comprises a mesh portion 103 and a grounding frame portion 101. The grounding frame 101 is grounded when installed on a display. As shown in FIG. 2, the mesh portion 103 includes a plurality of openings (also referred to as cells) 105 surrounded by a line 107. A mesh outer peripheral portion 104 may be provided between the mesh portion 103 and the grounding frame portion 101.
Further, a conductive material layer 109 is laminated on one surface of the transparent base material 11 via a conductive treatment layer 13. The conductive material layer 109 has a mesh shape in which the openings 105 are densely arranged, and the mesh includes the openings 105 and lines 107 forming a frame. As shown in FIG. 2, the width of the line portion 107 is referred to as a line width W, and an interval between lines is referred to as a pitch P.

  (Structure of Layer) FIG. 3A shows a cross section crossing the opening, in which the opening 105 and the line 107 are alternately formed, and FIG. 3B shows a cross section traversing the line 107. A line 107 consisting of 109 is formed continuously. The conductive material layer 109 mainly includes a metal plating layer (also simply referred to as a metal layer) 21. In addition, the conductive processing layer 13 and, if necessary, at least one surface of the metal plating layer 21 are blackened. It is provided with layers 23A and / or 23B. Further, rust prevention layers 25A and / or 25B are provided so as to cover at least one surface of the metal plating layer 21 and, when a blackening layer is provided, to cover the blackening layers 23A and / or 23B. The rust prevention layer may be provided at least on the blackening layer side. The rust preventive layers 25A and 25B have a rust preventive function of the metal plating layer 21 and the blackening layers 23A and 23B, and also prevent the blackening layers 23A and 23B from falling off. Therefore, the conductive material layer 109 includes the metal plating layer 21 as essential, and includes the blackening layers 23A and / or 23B and the rust prevention layers 25A and / or 25B as necessary.

  (Manufacturing method) The method for manufacturing the electromagnetic wave shielding sheet 1 of the present invention comprises the steps of (a) applying a conductive treatment layer to at least one surface of the transparent base material, and forming a metal layer as a metal plating layer by electrolytic plating thereon. A step of preparing the formed transparent substrate; and (b) a step of forming the metal plating layer and the conductive treatment layer of the metal-plated transparent substrate into a mesh by a photolithography method. First, first, a metal layer on the transparent substrate via the conductive treatment layer, and laminated at the same time as the layer formation by electrolytic plating method, and then processed into a mesh shape, including the material used, This will be described in detail.

(A) a step of applying a conductive treatment layer to one surface of the transparent base material and preparing a transparent base material on which a metal layer is formed as a metal plating layer (transparent base material) Various resin films and glasses can be applied as long as the resin has sufficient transparency, insulation, heat resistance, mechanical strength and the like to withstand use conditions and production.
As the glass, quartz glass, borosilicate glass, soda lime glass, or the like can be used. It is preferably a non-alkali glass which has a small coefficient of thermal expansion, excellent dimensional stability and workability in high-temperature heat treatment, and does not contain an alkali component in the glass, and which can also be used as an electrode substrate. Can be exemplified. The thickness of the glass is usually about 1 to 5 mm.

  Examples of the resin film include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Resin, polyamide resin such as nylon 6, polyolefin resin such as polypropylene and polymethylpentene, acrylic resin such as polyacrylate, polymethacrylate, polymethyl methacrylate, styrene resin such as ABS resin, and triacetyl cellulose And cellulose-based resins, imide-based resins and polycarbonates. It is used as a film, sheet, or board made of at least one layer of these resins, and these shapes are collectively referred to as a film in this specification. Usually, a polyester film such as polyethylene terephthalate or polyethylene naphthalate is preferably used because of its transparency, heat resistance and low cost, and polyethylene terephthalate is most suitable.

  When the transparent substrate 11 is made of a resin film, it may be a copolymer resin containing these resins as a main component, a mixture (including an alloy), or a laminate of a plurality of layers. The transparent substrate may be a stretched film or an unstretched film, but is preferably a film stretched in a uniaxial or biaxial direction for the purpose of improving strength. The thickness of the transparent substrate 11 can be generally about 12 to 1000 μm, preferably 50 to 700 μm, and most preferably 100 to 500 μm. If the thickness is less than this, the mechanical strength is insufficient, causing warpage or sagging. If the thickness is more than this, the performance becomes excessive and the cost is wasted.

  Instead of providing the blackening layer in FIG. 5 or in combination with the blackening layer, at least the surface of the transparent substrate 11 on which the metal plating layer is to be provided is processed into a mat shape so that the metal plating layer becomes matte. May be formed. In the mat-shaped metal layer, reflection of external light is low and glare can be reduced, so that the display quality of a display image is high. Further, when used in combination with the blackening layer, the contrast can be increased and good visibility can be obtained. However, when the surface of the transparent substrate 11 is matted, it is necessary to flatten the opening 105 by filling the mat-shaped fine irregularities with a flattening resin or an adhesive. The higher the transparency of the transparent substrate 11, the better, but preferably the visible light transmittance is 80% or more.

  The transparent substrate 11 is subjected to a corona discharge treatment, a plasma treatment, an ozone treatment, a frame treatment, a primer (also called an anchor coat, an adhesion promoter, and an easy-adhesive) treatment, and a pre-heat treatment on the conductive treatment surface prior to the conductive treatment. Alternatively, an easy adhesion treatment such as dust removal treatment, vapor deposition treatment, alkali treatment, or the like may be performed. When the transparent substrate is a resin film, additives such as a filler, a plasticizer, and an antistatic agent may be added as necessary.

  (Conductivity treatment) Conductivity treatment is performed on the transparent substrate 11 prior to metal electrolytic plating. As a method of the conductive treatment, a thin film of a known conductive material may be formed. The conductive material is made of, for example, a metal such as gold, silver, copper, iron, nickel, and chromium, or an alloy of these metals. Further, a transparent metal oxide such as tin oxide, ITO, or ATO may be used. The conductive treatment may be a single layer or a multi-layer. These materials are formed by a known method such as a vacuum deposition method, a sputtering method, and an electroless plating method to form the conductive treatment layer 13. The thickness of the conductive treatment layer 13 may be an extremely thin layer of about 0.001 to 1 μm, as long as necessary conductivity can be obtained at the time of plating.

  (Metal plating layer) A metal plating layer 21 is formed on the surface of the conductive treatment layer 13 to obtain a metal plating transparent substrate. As a material of the metal plating layer 21, for example, a metal having conductivity enough to shield electromagnetic waves, such as gold, silver, copper, iron, nickel, and chromium, or an alloy containing these metals can be used. The metal plating layer 21 may be a single layer or a multilayer, and is preferably made of copper or a copper alloy from the viewpoint of ease of electrolytic plating and conductivity. When a blackening layer and / or a chromate (treatment) layer is provided, copper or a copper alloy is preferable also from the viewpoint of adhesion and the like. The thickness of the metal plating layer 21 is about 1 to 100 μm, preferably 5 to 20 μm. If the thickness is less than this, mesh processing by the photolithography method becomes easy, but the electric resistance value of the metal increases and the electromagnetic wave shielding effect is impaired, and above this, the desired high-definition mesh shape cannot be obtained. As a result, the substantial aperture ratio is reduced, the light transmittance is reduced, the visual angle is also reduced, and the visibility of the image is reduced.

  (Blackening layer) In order to absorb external light to the electromagnetic wave shielding sheet 1 and improve the visibility of an image on the display, blackening processing is performed on the observation side of the mesh-shaped conductive material layer 109 to obtain contrast. It is necessary to give a feeling. For this purpose, a blackening layer 23A and / or 23B is provided on at least one side of the metal plating layer 21 as necessary. The blackening layer 23A may be formed by roughening and / or blackening the surface of the metal plating layer 21. In the case where the blackening layer 23A is provided on the surface of the transparent base material 11, the metal base layer 21 may be provided after conducting a conductive treatment on the transparent base material and providing the black plating layer.

  As the blackening layers 23A and 23B, formation of metal oxides and metal sulfides and various methods can be applied. In the case of iron, it is usually exposed to steam at a temperature of about 450 to 470 ° C. for 10 to 20 minutes to form an oxide film (blackened film) of about 1 to 2 μm. An oxide film (blackening film) may be used. In the case of copper, cathodic electrodeposition is preferred in which copper is subjected to a cathodic electrolysis treatment in an electrolytic solution composed of sulfuric acid, copper sulfate, cobalt sulfate or the like to attach cationic particles. By providing the cationic particles, the particles are roughened, and at the same time, a black color is obtained. As the cationic particles, copper particles and alloy particles of copper and another metal can be used, but copper-cobalt alloy particles are preferable. The average particle diameter of the cationic particles is preferably about 0.1 to 1 μm from the viewpoint of black density.

  In the present specification, the roughening and the blackening are collectively referred to as a blackening layer. The preferred black density of the blackened layer is 0.6 or more. The black density was measured by using COLOR CONTROL SYSTEM's GRETAG SPM100-11 (manufactured by KIMOTO Co., Ltd., trade name) with an observation viewing angle of 10 degrees, an observation light source D50, and an illumination type of standard density ANSIIT, and white color. After calibration, the test specimen is measured. The light reflectance of the blackening layer is preferably 5% or less. The light reflectance is measured using a haze meter HM150 (trade name, manufactured by Murakami Color Co., Ltd.) according to JIS-K7105. Instead of the measurement of the reflectance, the reflectance may be represented by a Y value of the reflection by a color difference meter. In this case, the Y value is preferably 10 or less.

(Rust preventive layer) Further, the rust preventive layer covers at least one side of the metal plating layer 21 and, if a blackened layer is provided, covers at least one side of the blackened layers 23A and / or 23B. 25A and / or 25B are provided.
The rust-proof layers 25A and 25B are preferably provided at least on the blackening layer in order to prevent rust and to prevent the blackening layer from falling off or deforming. As the rust prevention layer 25B, an oxide of nickel, zinc, and / or copper, or a chromate treatment layer can be applied. Nickel, zinc, and / or copper oxide may be formed by a known plating method, and has a thickness of about 0.001 to 1 μm, preferably 0.001 to 0.1 μm.

  In the case where the rust-preventive layer 25A is provided on the blackening layer 23A of the transparent substrate 11, the conductive process is performed on the transparent substrate, and the rust-preventive layer 25A is provided by the same material and method as in the above-described 25B. Good. In this case, a black plating layer (corresponding to the blackening layer 23A), a metal plating layer 21, and, if necessary, a blackening layer 23B and a rust prevention layer 25B are sequentially provided on the surface of the rust prevention layer 25A. Go.

(Chromate) In the chromate treatment, a chromate treatment liquid is applied to a material to be treated and treated. As the coating method, a roll coat, a curtain coat, a squeeze coat, an electrostatic atomization method, an immersion method, or the like can be applied. When the chromate treatment is performed on one side, it may be applied on one side by roll coating or the like, and when performed on both sides, it may be performed by a dipping method. As the chromate treatment liquid, an aqueous solution containing 3 g / l of CrO ₂ is usually used. In addition, a chromate treatment solution in which a part of hexavalent chromium is reduced to trivalent chromium by adding a different oxycarboxylic acid compound to an aqueous solution of chromic anhydride can also be used. The color changes from pale yellow to yellowish brown depending on the amount of hexavalent chromium deposited. However, trivalent chromium is colorless, and if trivalent and hexavalent chromium are controlled, transparency without practical problems can be obtained. Can be As the oxycarboxylic acid compound, tartaric acid, malonic acid, citric acid, lactic acid, glycolic acid, glyceric acid, tropic acid, benzylic acid, hydroxyvaleric acid or the like is used alone or in combination. Since the reducibility differs depending on the compound, the addition amount is determined while grasping the reduction to trivalent chromium.
Specifically, Alsurf 1000 (manufactured by Nippon Paint Co., Ltd., trade name of chromate treatment agent), PM-284 (manufactured by Nippon Parkerizing Co., Ltd., trade name of chromate treatment liquid) and the like can be exemplified. In addition, the chromate treatment prevents the rust prevention function and the blackening layer from falling off or deformed, and further enhances the effects of the blackening layers 23A and 23B.

  The blackening layers 23A and 23B and the rust prevention layers 25A and 25B may be provided at least on the observation side, and the contrast is improved and the visibility of the image on the display is improved. Further, it may be provided on the other surface, that is, on the display surface side, and stray light generated from the display can be suppressed, so that the visibility of the image is further improved.

(B) A step of forming the metal plating layer (metal layer) and the conductive treatment layer of the metal-plated transparent base material into a mesh by a photolithography method. The metal layer (metal) of the metal-plated transparent base material prepared as described above. (Plating layer) A resist layer is provided on the surface of 21, mesh-patterned, a portion of the metal layer 21 not covered with the resist layer is removed by etching, and then the resist layer is removed. Metal layer. Furthermore, existing equipment can be used, and many of these manufacturing steps are performed continuously, so that high quality, high production efficiency, high yield, and inexpensive production can be achieved.

  (Photolithography method) A photolithography method in which a resist layer is provided in a mesh pattern on the surface of the conductive material layer of the laminate, and a portion of the conductive material layer not covered with the resist layer is removed by etching, and then the resist layer is removed. To make a mesh. In addition, the conductive material layer is a generic name of the conductive processing layer 13, the metal layer 21, and, if necessary, the blackening layers 23A and / or 23B and the rust preventing layers 25A and / or 25B.

  (Masking) First, the surface of the conductive material layer 109 of the laminate of the transparent base material 11 and the conductive material layer 109 is formed into a mesh shape by photolithography. In this step as well, a roll-shaped laminate that is continuously wound in a belt shape is processed (called a winding process or a roll-to-roll process). While the laminate is continuously or intermittently conveyed, masking, etching, and resist peeling are performed in a stretched state without looseness. When glass is used as the transparent substrate 11, it is processed one by one (referred to as a single-wafer processing or single-wafer process).

  First, in masking, for example, a photosensitive resist is applied onto the conductive material layer 109, dried, and then tightly exposed with a predetermined pattern plate (photomask), water-developed, hardened, and baked. I do. In addition, any of a negative type and a positive type of a photosensitive resist can be used. When the photosensitive resist is a negative type, the mesh pattern of the pattern plate is a positive (positive image) having transparent line portions. When the photosensitive resist is a positive type, the mesh pattern of the pattern plate is a negative (negative image) having a transparent opening. The exposure pattern is a pattern desired as an electromagnetic wave shielding sheet, and is composed of at least a mesh portion pattern. If necessary, as shown in FIG. 1, a pattern of a grounding frame portion is added to the outer periphery of the mesh portion.

  In the winding process, a resist such as casein, PVA, gelatin or the like is applied to the surface of the conductive material layer 109 while continuously or intermittently transporting the belt-shaped laminate (transparent substrate 11 and conductive material layer 109). By dipping (dipping), curtain coating, pouring, and the like. Further, the resist may be a dry film resist instead of the coating, and the workability can be improved. In the case of a casein resist, baking is performed at 200 to 300 ° C., but the temperature is preferably as low as possible in order to prevent warpage of the laminate.

  (Etching) Etching is performed after masking. As the etchant used for the etching, a solution of ferric chloride and cupric chloride which can be easily used in circulation in the present invention in which etching is performed continuously is preferable. The etching is basically the same as the equipment for manufacturing a shadow mask for a color TV cathode-ray tube for etching a strip-shaped continuous steel material, particularly a thin plate having a thickness of 20 to 80 μm. That is, the existing manufacturing equipment for the shadow mask can be diverted, and the entire process from masking to etching can be performed continuously and continuously, which is extremely efficient. Single-wafer processing in the case of using glass as the transparent substrate 11 has been performed for a long time. After the etching, the substrate may be washed with water, stripped of resist with an alkaline solution, washed, and then dried. Since the transparent substrate is exposed on the surface of the mesh opening thus formed, the transparency of the mesh opening is good.

(Mesh) The mesh part 103 is composed of a plurality of openings 105 surrounded by a line 107 part. The shape of the opening 105 in plan view is not particularly limited. For example, for example, a triangle such as a regular triangle, a square such as a square, a rectangle, a rhombus, a trapezoid, a polygon such as a hexagon or an octagon, a circle, or an ellipse Shapes and the like can be applied. A mesh is formed by combining a plurality of these openings.
From the viewpoint of aperture ratio, mesh invisibility, and image visibility, the mesh portion 103 preferably has a line width W of 5 to 25 μm and a line-to-line pitch of 150 to 500 μm.
The bias angle formed by the line with one side of the edge of the electromagnetic wave shielding sheet is 45 degrees in the illustration of FIG. 1, but is not limited thereto. It may be appropriately selected in consideration of light emission characteristics.

  (Modification) The electromagnetic wave shielding sheet and the method of manufacturing the same according to the present invention are indispensable. However, in order to further form a front plate, as shown in FIG. 5, a flattening layer 29, a near infrared ray (NIR) An absorption layer 31A and / or 31B, an antireflection (AR) layer, a hard coat layer, an antifouling layer, an antiglare layer, and the like may be provided. Furthermore, since the whole structure using inorganic material as the transparent substrate 11 is an inorganic material, an electrode can be provided by providing an electrode on the back surface of the glass, or the glass can be distorted or processed at a high temperature. .

  (Planarization) When the mesh is formed, the mesh line portion 107 becomes a convex portion due to the thickness of the metal, but the opening portion 105 is opened by removing the metal plating layer to form a cavity and a concave portion. The part forms an uneven surface. For this reason, a flattening operation may be required. When an adhesive or a pressure-sensitive adhesive is applied in the next step, the uneven surface of the mesh portion is difficult to completely fill with the adhesive or the like, and air tends to remain in the concave portion. If air remains in the concave portion, light is scattered and whitened at the adhesive / adhesive interface, and the display image becomes unclear, which is not preferable. For the flattening, a transparent resin is applied to and embedded in the concave portion. However, if the resin does not penetrate into every corner of the concave portion, bubbles remain and the transparency is deteriorated. For this reason, it is diluted with a solvent or the like and applied with a low viscosity and dried, or applied while degassing air, and further, a base film coated with an adhesive is laminated, and the remaining air bubbles are removed. The flattening layer 29 is formed with care.

  The flattening layer 29 may have high transparency, good adhesion to the conductive material layer of the mesh, and good adhesion to the adhesive in the next step. However, if the surface of the flattening layer 29 has protrusions, dents, and unevenness, it is not preferable because moire, interference unevenness, and Newton's ring occur when installed on the front surface of the display. As a preferable method for preventing such a problem, after applying a heat or ultraviolet curable resin as a resin, laminating on a substrate having excellent flatness and releasable, and curing the applied resin with heat or ultraviolet light Then, the peelable substrate is peeled and removed. The surface of the flattening layer 29 is transferred to the surface of the flat base material to form a smooth surface.

  The resin used for the flattening layer 29 is not particularly limited, and various natural or synthetic resins, heat or ionizing radiation curable resins, and the like can be applied. However, the durability, applicability, ease of flattening, and flatness of the resin are used. Therefore, an acrylic ultraviolet curable resin is preferable.

  (NIR Layer) Further, a light absorbing agent that absorbs a specific wavelength band of visible and / or near-infrared rays may be added to the resin used for the flattening layer 29. For example, in the case of a PDP, light in the 570 to 620 nm band of the neon atom spectrum is radiated in addition to the image light. Since the color reproduction of the image is disturbed by absorbing light in this band, discomfort is suppressed, and the band color reproduction of the image is improved. In the case of a PDP, near infrared rays (NIR) in a specific wavelength band are radiated in addition to image light. Such a near product line has the same wavelength band as the near-infrared ray used for communication of the remote control device, and thus causes malfunction and needs to be removed. The specific wavelength of such near-infrared rays is about 780 to 1100 nm. It is desirable to absorb 80% or more of the wavelength range of 780 to 1000 nm. The near-infrared absorbing agent (referred to as NIR absorbing agent) is not particularly limited, but has a sharp absorption in a near-infrared region, a high light transmittance in a visible light region, and a specific wavelength in a visible light region. Dyes without large absorption can be applied. As a visible light region emitted from a PDP display, there are usually many orange colors which are neon light, and therefore, those which absorb to some extent around 780 to 900 nm are preferable. Examples of the dye include diimonium compounds, cyanine compounds, phthalocyanine compounds, naphthalocyanine compounds, naphthoquinone compounds, anthraquinone compounds, and dithiol complexes. When the NIR absorber is not added to the flattening layer 29, another layer having an NIR absorber (referred to as an NIR layer) may be provided on at least one surface.

  (NIR Separate Layer) The NIR layer is provided on the flattening layer 29 side and / or the transparent substrate 11 side on the opposite side, and when provided on the flattening layer 29 side, the NIR layer 31B shown in FIG. When it is provided on the surface of the base material 11, it is the NIR layer 31A shown in FIG. The NIR layer 31B and the NIR layer 31A are formed by laminating a commercially available film having an NIR absorber (for example, Toyobo Co., Ltd., trade name No. 2832) with an adhesive, or by applying the above NIR absorber to a binder. You may. As the binder, a polyester resin, a polyurethane resin, an acrylic resin, or a curing type utilizing a reaction of an epoxy, acrylate, methacrylate, isocyanate group or the like which is cured by heat or ultraviolet rays can be applied.

  (AR layer) Further, although not shown, an antireflection layer (referred to as an AR layer) may be provided on the observation side of the electromagnetic wave shielding sheet. The anti-reflection layer is for preventing reflection of visible light, such as sunlight and illumination light, incident on the display from the outside, and has a single-layer or multi-layer configuration with many specifications on the market. At least an antireflection layer and / or an antiglare layer is provided on the surface of the transparent base film 11 in order to provide an antireflection function. Further, a commercially available transparent film having an anti-reflection function such as an anti-reflection film TAC-AR1 (trade name, manufactured by Dai Nippon Printing Co., Ltd.) may be used. The anti-reflection function reduces reflection of a screen caused by external light from the sun, a fluorescent lamp, or the like incident on the PDP screen and reflected. Further, by suppressing the reflectance of the surface, the contrast of the image is improved, and as a result, the visibility of the image is improved.

(Anti-reflection layer) In the present specification, the so-called "anti-reflection layer" means a structure in which one or more transparent dielectric layers are laminated on the surface of the transparent base material 11.
The refractive index of the outermost layer of the dielectric layer is determined by adjusting the refractive index of the outermost layer to the layer immediately below it (a transparent substrate, a dielectric layer immediately below, or a hard coat layer when an antireflection layer is laminated on a hard coat layer as described later). (Coating layer), and the optical thickness (refractive index × geometric thickness) of the dielectric layer is set to １ ／ of the wavelength of light to be prevented from being reflected. With such a configuration, the reflected light from each layer interface is attenuated by interference.

Typical layer configurations of the antireflection layer include (1) transparent base film / [low refractive index layer], (2) transparent base film / [high refractive index layer / low refractive index layer], (3) Transparent base film / [low refractive index layer / high refractive index layer / low refractive index layer], (4) transparent base film / [high refractive index layer / medium refractive index layer / low refractive index layer] and the like. . Here, [] indicates the configuration of the antireflection layer.
Examples of the material of each layer constituting the anti-reflection layer include, for the low refractive index layer, inorganic materials such as magnesium fluoride (MgF ₂ ) and cryolite, or a low refractive index resin composition as described later. For the high refractive index layer, inorganic substances such as titanium dioxide, zinc sulfide, and antimony oxide are exemplified. The antireflection layer is produced by a known dry coating method such as vapor deposition or sputtering, or a wet coating method such as roll coating or lip die coating.

  Specifically, (1) a high-refractive-index layer made of zinc sulfide having a refractive index of 2.3 and a low-refractive-index layer made of magnesium fluoride having a refractive index of 1.38 (a transparent base film) / [High-refractive-index layer / low-refractive-index layer / high-refractive-index layer / low-refractive-index layer]) in this order. The optical thickness of each layer is set to １ ／ of the D line (≒ 590 nm) of the sodium atom spectrum in the vicinity of the middle of the visible light band. (2) A low-refractive-index layer composed of a low-refractive-index resin composition is applied on the surface of a transparent base film by a lip-die coating method and laminated. The optical thickness of the low-refractive-index layer is set to ≒ of the D line (≒ 590 nm) of the sodium atom spectrum at a wavelength near the middle of the visible light band.

  The low-refractive-index resin composition comprises a dispersion of transparent fine particles having an average particle diameter of 5 to 300 nm in an ionizing radiation-curable resin containing a fluorine atom in a molecule. The low-refractive-index resin composition is applied to the surface of a transparent base material film, cross-linked by irradiation with ionizing radiation, and cured, so that an average pore size of 0.01 to 100 nm is formed inside and / or on the surface of the cured coating film. A large number of air-containing pores are formed, forming a porous coating. Such an ionizing radiation-curable resin containing a fluorine atom in the molecule itself has a lower refractive index than ordinary resins, and the coating film is porous and contains air, so that the average refractive index of the coating film is increased. The index approaches the refractive index of air (1.0), resulting in a lower refractive index of the coating.

  The ionizing radiation-curable resin containing a fluorine atom in the molecule is a polymer having a number average molecular weight of about 20,000 to 500,000, which contains a fluorine atom in the molecule and has an ionizing radiation-curable functional group. A compound having a radically polymerizable unsaturated group such as a (meth) acryloyl group and a cationically polymerizable functional group such as an epoxy group is an essential component. (Here, “(meth) acryloyl group” means “acryloyl group or methacryloyl group”). Examples of the ionizing radiation-curable resin containing a fluorine atom in such a molecule include homopolymers of fluorine atom-containing monomers such as fluoroethylene, or fluorine atom-containing monomers and pentaerythritol triacrylate. It is obtained as a copolymer with a monomer containing no fluorine atom. If necessary, a monomer having three or more ionizing radiation-curable functional groups in one molecule may be added to the polymer. The monomer may or may not contain a fluorine atom. Note that as the ionizing radiation, an electron beam, ultraviolet light, or the like is typically used.

  As the fine particles, particles such as hollow particles and porous particles containing air inside the particles themselves contain air. Alternatively, even if the particles themselves do not contain air, when dispersed in the ionizing radiation-curable resin, air is attached to the surroundings to produce fine-particle bubbles, and a plurality of (primary) particles are aggregated. It may be a material that aggregates and contains air. Examples of the fine particles include hollow silica particles, porous silica particles, colloidal silica, and acrylic aggregated particles. The addition amount of the fine particles is about 1 to 400 parts by mass with respect to 100 parts by mass of the ionizing radiation curable resin containing a fluorine atom in the molecule.

(Hard coat layer, antifouling layer, antiglare layer) Further, the antireflection (AR) layer may be provided with a hard coat layer, an antifouling layer, and an antiglare layer.
(Hard Coat Layer) The hard coat layer is a layer having a hardness of H or more in a pencil hardness test according to JIS-K5400, and is a polyfunctional (meta) such as polyester (meth) acrylate, urethane (meth) acrylate, and epoxy (meth) acrylate. ) Acrylate prepolymer, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate and other polyfunctional (meth) acrylate monomers, etc., alone or as a mixture of two or more, are coated. Cured with heat or ionizing radiation.

  (Anti-glare layer) In the present specification, a so-called "anti-glare layer" is a method of causing a display image to be glazed by diffusing (scattering) light by fine irregularities on the surface of the layer or fine refractive index fine particles dispersed inside the layer. It is called the one that prevents the feeling of flicker. Regarding the optical properties of the antiglare property, the haze value is 3% or more, preferably 3 to 40%, more preferably 5 to 30%. When the haze value is less than 3%, the antiglare property is insufficient, and when the haze value exceeds 40%, the light transmittance deteriorates. The 60 ° gloss is 100 or less, more preferably 90 or less, and even more preferably 50 to 85. If the 60 ° gloss exceeds 100, the antiglare property becomes insufficient due to the surface gloss due to reflection. The transmission clarity is 100 or more, more preferably 150 or more, and further preferably 200 to 300. If the transmission sharpness is less than 100, the visibility is insufficient. The total light transmittance is 70% or more, more preferably 75% or more, and further preferably 80 to 95%. When the total light transmittance is less than 70%, transparency is insufficient. Is generally good for antiglare property, visibility, light transmittance, transparency and the like.

  The antiglare layer may be a known one, and is preferably a layer containing an inorganic filler such as silica, or a layer having a fine uneven surface that irregularly reflects external light. Examples of the layer containing an inorganic filler include acrylic resins such as polyacrylate copolymers including ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and t-butyl acrylate, diene resins, polyester resins, and silicone resins. In the curable resin, silica particles having an average particle diameter of usually 30 μm or less, preferably about 2 to 15 μm, and about 0.1 to 10 parts by mass of silica particles are dispersed with respect to 100 parts by mass of the resin. It is applied and dried by a reverse roll coat, a die coat or the like so that the thickness after drying is about 5 to 30 μm, and is cured by irradiation with heat, ultraviolet rays or electron beams as necessary.

  As a layer having a fine uneven surface, a transparent resin is applied and the unevenness is embossed on the coating film, or the transparent resin is applied to a plate cylinder having the unevenness, cured by UV, and then peeled off to remove the unevenness on the surface. A well-known method of transferring or applying a transparent resin to a shaping film having unevenness, curing with UV, and then peeling to transfer the unevenness to the surface can be applied.

(Anti-fouling layer) The anti-fouling layer is generally a water-repellent and oil-repellent coat to which a siloxane-based or fluorinated alkylsilyl compound can be applied. A fluorine-based or silicone-based resin used as a water-repellent paint can be suitably used. For example, when the low refractive index layer of the antireflection layer is formed of SiO ₂ , a fluorosilicate-based water-repellent paint is preferably used.

  (Sheet formation) In the case of manufacturing by winding, the members are cut to obtain one electromagnetic wave shielding sheet 1 for each sheet. The electromagnetic wave shielding sheet 1 is attached to a transparent substrate such as glass, and if necessary, combined with an NIR layer, an AR layer, a hard coat layer, an antifouling layer, and an antiglare layer to form a display front plate. It becomes. The substrate has a rigidity with a thickness of 1 to 10 mm for a large display, and a plastic film with a thickness of 0.01 to 0.5 mm is used for a small display such as a character display tube. , May be selected as appropriate according to the size and use of the display. Here, since the electromagnetic wave shielding sheet 1 is once set as a display front plate and then placed on the front of the display, the transparent substrate 11 side is the observation side, but it may be directly adhered to the front of the spray.

  (Electrode plate) When the transparent substrate 11 is made of glass, the entire layer structure is an inorganic substance, so that a high-temperature treatment can be performed. For this reason, an electrode is provided on the back surface of the glass plate as the transparent base material 11 to serve as an electrode plate, which can also be used as an electrode plate of a PDP or LCD, thereby saving resources. In addition, distortion of glass generated during glass production or processing can be removed by heat treatment.

FIG. 6 is a cross-sectional view of the electromagnetic wave shielding sheet of the present invention adhered to a display surface.
(Direct attachment) In this case, the metal plating layer side in the mesh shape is the observation side, and at least a blackening layer and a rust prevention layer may be provided on the metal plating layer side. Since the grounding frame 101 is exposed to the surface, the electrodes are easily pulled out and the ground is easily taken. Further, since the grounding frame portion 101 is blackened and the black surface is the observation side, the black printing provided in the frame shape of the front glass plate is unnecessary, the process can be shortened, and the cost is advantageous. is there.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but is not limited thereto.

(Cu plating only) As a transparent substrate, a continuous belt-shaped (called winding) PET film A4300 (manufactured by Toyobo Co., Ltd., biaxially stretched polyethylene terephthalate) having a thickness of 100 μm was prepared. On one surface of the transparent substrate, a copper layer (conductive treatment layer) having a thickness of 0.5 μm was provided by a vacuum evaporation method to form a conductive treatment layer. A copper layer (metal plating layer) having a thickness of 10 μm was formed on the surface of the conductive treatment layer by electrolytic plating to form a metal layer, and a conductive material layer including the conductive treatment layer and the metal layer was formed on a transparent substrate. Thus, a copper-plated transparent substrate (metal-plated transparent substrate) was prepared. A mesh is formed on the copper layer surface of the copper-plated transparent substrate by photolithography.
For the formation of the mesh by the photolithography method, a production line for a color TV shadow mask, which performs from masking to etching in a continuous band, was used. First, a negative photosensitive resist of casein was applied over the entire surface of the conductive material layer by a flowing method. The substrate was transported to the next station, and was subjected to contact exposure using a pattern plate of a negative pattern (opening was light-shielding, line was translucent) having the following shape. While transporting the stations one after another, water development was performed to leave the resist only at the exposed portions, hardening treatment was performed, and baking was performed at 100 ° C.
The shape of the pattern plate is such that the mesh portion has an opening of the mesh portion having a square shape in plan view with a line width of 22 μm, a line interval (pitch) of 300 μm, and a bias angle of 49 degrees. An outer peripheral portion of a 5 mm wide mesh made of a square mesh with a space of 300 μm in plan view was provided, and the outer peripheral portion was further formed as a grounding frame portion (earth portion) made of a continuous film having no 5 mm wide opening ( The overall plan view shape is as shown in FIG. 1).
Further, it is conveyed to the next station, and using a ferric chloride solution at 40 ° C. and 40 ° Bohm as an etching solution, spraying is performed by a spray method to etch away only the conductive material layer in the non-resist forming portion, and to perform etching. Was formed. While successively transporting the station, the sheet was washed with water, the resist was peeled off, washed, dried at 100 ° C., and then cut into a desired size to obtain the electromagnetic wave shielding sheet of Example 1.

  (Matte PET) A matte mirror having a thickness of 100 μm (trade name of a biaxially stretched polyethylene terephthalate film having a matte surface) manufactured by Toray Co., Ltd. In the same manner as in Example 1, an electromagnetic wave shielding sheet was obtained.

  (Cu plating / blackening layer) Copper-cobalt alloy particles having an average particle diameter of 0.3 μm by a cathodic electrodeposition method on the copper layer (metal plating layer) surface of the copper-plated transparent substrate obtained in Example 1. An electromagnetic wave shielding sheet was obtained in the same manner as in Example 1 except that a blackening layer was formed and a metal-plated transparent substrate was used.

  (Cu plating / blackening layer / rust prevention layer) PM-284 (manufactured by Nippon Parkerizing Co., Ltd.) was used as a chromate treatment liquid for the blackening layer surface of the copper plating transparent substrate with the blackening layer obtained in Example 3. Chromate treatment liquid (trade name), coated by a roll coating method, dried, subjected to chromate treatment, provided with a rust-proof layer, and used as a metal-plated transparent substrate in the same manner as in Example 3. Thus, an electromagnetic wave shielding sheet was obtained.

(PET / conductive / black plating / metal plating / blackening layer)
As a metal-plated transparent substrate, a 100 μm thick matte mirror (trade name of a biaxially stretched polyethylene terephthalate film having a matte surface manufactured by Toray Industries, Inc.) and a conductive treatment layer (0.5 μm thick by sputtering) ITO (formed of ITO), blackening layer (formed of 1 μm thick copper-cobalt particle layer by plating), metal plated layer (formed of 10 μm of copper by electrolytic plating), blackened layer (plated) An electromagnetic wave shielding sheet was obtained in the same manner as in Example 1 except that a copper-cobalt particle layer having a thickness of 1 μm was formed by a method.

(Glass / Cu plating only) Soda-lime glass having a thickness of 3 mm was prepared as a transparent base material, and a copper layer (conductive treatment layer) having a thickness of 0.3 μm was provided on one surface thereof by a sputtering method. A copper layer (metal layer) having a thickness of 10 μm was provided on the surface of the conductive layer by electrolytic plating. A mesh is formed on the copper layer surface of the copper-plated glass substrate by photolithography.
The formation of the mesh by the photolithography method is as follows. First, a negative photosensitive dry resist film is attached to the entire surface of the conductive material layer on a sheet-by-sheet basis, and a negative pattern having the following shape (opening is light-shielding, Using a pattern plate having a light-transmitting line portion, the substrate was exposed in close contact, and developed with water to leave a resist on only the exposed portion, hardening was performed, and further baked at 100 ° C.
The shape of the pattern plate is such that the mesh portion has an opening of the mesh portion having a square shape in plan view with a line width of 22 μm, a line interval (pitch) of 300 μm, and a bias angle of 49 degrees. An outer peripheral portion of a 5 mm wide mesh made of a square mesh with a space of 300 μm in plan view was provided, and the outer peripheral portion was further formed as a grounding frame portion (earth portion) made of a continuous film having no 5 mm wide opening ( The overall plan view shape is as shown in FIG. 1).
Further, using a ferric chloride solution of 40 ° C. and 40 ° Baume as an etchant, spraying is performed by a spray method to etch away only the conductive material layer in the non-resist forming area, thereby forming an opening, washing with water. The resist was peeled off, washed, and dried at 100 ° C. to obtain an electromagnetic wave shielding sheet.

  (Glass / Cu plating / blackening layer) A blackening layer composed of copper-cobalt alloy particles having an average particle diameter of 0.3 μm is formed on the copper layer (metal layer) surface by cathodic electrodeposition, and the metal plating transparent substrate is formed. Except for using the material, an electromagnetic wave shielding sheet was obtained in the same manner as in Example 6.

  (Glass / Cu plating / blackening layer / rust prevention layer) PM-284 (Nihon Parkerizing) was used as a chromate treatment solution for the blackening layer surface of the copper plating transparent substrate with the blackening layer obtained in Example 7. Chromate treatment solution (trade name, manufactured by Co., Ltd.), applied by a roll coating method, dried, subjected to chromate treatment, provided with a rust-proof layer, and used as a metal-plated transparent substrate, in the same manner as in Example 6. Thus, an electromagnetic wave shielding sheet was obtained.

  (Comparative Example 1, adhesive laminating method) As a conductive material layer, a blackening layer composed of copper-cobalt alloy particles having an average particle diameter of 0.3 μm and a rust prevention layer composed of a chromate (treatment) layer having a thickness of 10 μm were added. Using the electrolytic metal foil of the above, a chromate (treated) layer surface of the copper-cobalt alloy particles and a PET film A4300 (a product name of a biaxially stretched polyethylene terephthalate film manufactured by Toyobo Co., Ltd.) having a layer thickness of 100 μm were After lamination by dry lamination with a two-component curing type polyurethane adhesive, aging was performed at 56 ° C. for 4 days. As the adhesive, the main agent was polyol Takerak A-310 and the curing agent was isocyanate A-10 (both manufactured by Takeda Pharmaceutical Co., Ltd., trade name), and the coating amount was 7 μm in thickness after drying. The formation of the mesh by photolithography was performed in the same manner as in Example 1 to obtain an electromagnetic wave shielding sheet.

(Comparative Example 2, solid coating of photosensitive coating solution containing chemical plating catalyst-photolithography-copper plating) To PET film A4300 (product name of biaxially stretched polyethylene terephthalate film manufactured by Toyobo Co., Ltd.) having a thickness of 100 µm as a transparent substrate. A negative photosensitive coating solution containing a chemical plating catalyst having the following composition was applied to the entire surface by spin coating at 1500 rpm for 20 seconds, and prebaked at 50 ° C. for 15 minutes. As the above-mentioned photosensitive coating solution containing a chemical plating catalyst, a photosensitive coating solution containing SOC-PA (trade name of palladium (Pd) -based photo-resolution chemical plating catalyst manufactured by Sumitomo Osaka Cement Co., Ltd.) was used.
Next, by a photolithography method using a negative pattern plate having the same shape as in Example 1, ultraviolet exposure, development with ion-exchanged water, washing, and formation of a mesh were performed. By baking for a minute, a mesh-like Pd catalyst layer was obtained.
Further, a 10 μm-thick copper layer is formed on the mesh by an electroless plating method in which it is immersed in OPC750 (trade name of an electroless copper plating solution manufactured by Okuno Pharmaceutical Co., Ltd.), washed, dried, and then dried. The sheet was cut into dimensions to obtain an electromagnetic wave shielding sheet.

(Results) The electromagnetic wave shielding sheets of Examples 1 to 8 were excellent in electromagnetic wave shielding properties and mesh accuracy, and excellent in transparency. In addition, when these were processed into a front plate and placed on the front of a display such as a PDP, the electromagnetic waves generated from the display were shielded, and an image was displayed to evaluate the visibility. Met.
Furthermore, in the production, warpage and mixing of air bubbles were small, and the production was good in a short process and the production was inexpensive.
In Comparative Example 1, many bubbles having a diameter of about 50 μm were mixed in the adhesive, and the transparency was poor. In addition, in the electromagnetic wave shielding sheet near the winding core of the winding, the yield was reduced due to warpage, and the production efficiency in the cutting and assembling process was significantly reduced.
In Comparative Example 2, although the accuracy of the mesh was good, the uniformity of the plating layer thickness in the mesh surface was poor, and the electromagnetic wave shielding effect was uneven. At the time of manufacture, the plating time was as long as about 80 minutes per 2 μm, and the productivity was poor.

  (Combined use as an electrode plate) After the electromagnetic wave shielding sheet obtained in Example 6 was annealed by high-temperature heat treatment at 200 ° C. for 30 minutes, ITO was applied to the glass surface opposite to the metal layer by a sputtering method. When an electrode was formed with a thickness of 5 μm, no distortion was observed in the glass plate, and the ITO film functioned as an electrode.

It is a top view of the sheet for electromagnetic wave shielding of the present invention. It is a perspective view showing typically a part of sheet for electromagnetic wave shielding of the present invention. FIG. 3 is an AA sectional view and a BB sectional view of FIG. 2. FIG. 3 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. 2 after blackening processing. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the sheet for electromagnetic wave shielding which shows one Example of this invention. It is sectional drawing of the sheet for electromagnetic wave shielding of this invention stuck on a display surface.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Electromagnetic wave shielding sheet 11 Transparent base material 13 Conductive treatment layer 21 Metal plating layer 23A, 23B Blackening layer 25A, 25B Rust prevention layer 29 Flattening layer 31A, 31B NIR layer 101 Grounding frame 103 Mesh 105 Opening 107 Line part 109 Conductive material part

Claims (7)

In the method for producing an electromagnetic wave shielding sheet having a mesh-shaped metal layer on one surface of a transparent substrate, at least (a) a conductive treatment layer is applied to one surface of the transparent substrate, and electrolytic plating is performed on the conductive treatment layer. A step of preparing a transparent substrate having a metal layer formed thereon as a metal plating layer; and (b) a step of forming the metal plating layer and the conductive treatment layer of the metal-plated transparent substrate into a mesh by photolithography. A method for producing an electromagnetic wave shielding sheet, comprising: The method for producing an electromagnetic wave shielding sheet according to claim 1, wherein the transparent substrate is glass, and the steps (a) and (b) are performed in a single-wafer state. In an electromagnetic wave shielding sheet having a mesh-shaped metal layer on one surface of a transparent substrate, at least (a) a conductive treatment layer is applied to one surface of the transparent substrate, and a metal plating layer is formed thereon by electrolytic plating. Preparing a transparent substrate having a metal layer formed thereon, and (b) forming a metal plating layer and a conductive treatment layer of the metal-plated transparent substrate into a mesh by photolithography. An electromagnetic wave shielding sheet, which is manufactured. The electromagnetic wave shielding sheet according to claim 3, wherein a blackening layer is provided on at least one surface of the metal plating layer. The electromagnetic wave shielding sheet according to any one of claims 3 to 4, further comprising a rust preventive layer on at least one surface of the metal plating layer or the blackening layer. The electromagnetic shielding material according to any one of claims 3 to 5, wherein at least the surface of the metal plating layer of the transparent substrate is mat-shaped, and the material of the transparent substrate is a polyester resin. Sheet. The electromagnetic wave shielding sheet according to any one of claims 3 to 5, wherein the material of the transparent substrate is glass, and all the constituent materials are made of an inorganic substance.

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