JP2012169354A - Front filter for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter for plasma display in which contact state of a conductive pattern layer and a conductive gasket is excellent, and the ground resistance is reduced.SOLUTION: Various functional layers 300 are laminated on a conductive pattern layer 10 side at a part of an electromagnetic wave shield layer 100, having the conductive pattern layer 10 containing conductive particles and a resin binder formed in a predetermined pattern on a transparent substrate 20, excepting the peripheral edge thereof, with an adhesive layer 200 interposed therebetween, and the conductive pattern layer 10 side at the peripheral edge of the electromagnetic wave shield layer 100 is connected, at least partially, with a metal frame ground part via a conductive gasket 400. In such a filter, a metal layer having a projecting end corner and a recessed central part is formed on the surface of the conductive pattern layer 10 of the electromagnetic wave shield layer 100, and a blackened layer of an acicular metal is formed on the surface of the metal layer.

Description

  The present invention relates to a plasma display filter suitable for being placed on the front surface of a plasma display.

In recent years, with the increase in size and thickness of image display devices, plasma displays (PDP) have attracted attention.
Since PDP uses plasma discharge for light emission, unnecessary electromagnetic waves in the 30 MHz to 1 GHz band may leak to the outside and affect other devices (for example, remote control devices, information processing devices, etc.). Therefore, a film-like electromagnetic wave shielding member for shielding (shielding) electromagnetic waves that leak while maintaining the transparency of image light on the front side (observer side) of the plasma display panel used in the plasma display device. It is common to provide it.
In the present invention, the term “electromagnetic wave” means an electromagnetic wave in the vicinity of the KHz to GHz band whose frequency is centered on the above range. It does not include infrared rays, visible rays, ultraviolet rays, X-rays, etc. (for example, electromagnetic waves having a frequency in the infrared band are referred to as infrared rays).

Electromagnetic wave shielding member materials that can be used for the front surface of plasma displays include silver sputtered thin films and copper mesh, but silver sputtered thin films are expensive and cover the entire surface, so visible light (line) Poor compatibility between transparency and electromagnetic wave shielding. Since the copper mesh has an opening, the transparency is high, but the copper foil is etched by a photolithography method to create a mesh shape.
In recent years, an electromagnetic shielding member has been proposed in which a conductive paste or ink containing a catalyst for electroless plating is printed on a transparent substrate by pattern printing, such as intaglio printing, and copper is deposited thereon to form a fine line pattern. (Patent Documents 1 and 2), it can be said that the method is more economical and more productive than the copper foil etching method.

  The present applicant transfers a conductive material composition onto a transparent substrate by intaglio printing, and in an electromagnetic wave shielding material formed with a conductive pattern, the pattern breakage based on the transfer failure of the conductive material composition Have proposed an electromagnetic shielding material that does not cause defects such as poor shape, insufficient transfer rate, and low adhesion (Patent Document 3). In this invention, the primer on the surface of the conductive ink composition filled in the recess (cell) of the intaglio plate is pressure-bonded with a transparent substrate on which a primer layer capable of maintaining fluidity is formed until it is cured. The primer layer is cured through a pressure-bonding process in which the layer and the conductive ink in the recess are in close contact with each other without a gap, and then the transparent substrate is peeled off from the plate surface, and the conductive ink composition in the recess is cured on the primer layer. Transcript.

According to such an intaglio printing method, since there is no transfer failure of the conductive composition, the pattern shape of the original intaglio is faithfully transferred to the conductive convex pattern layer.
As an intaglio, a square lattice mesh pattern in which the cross-sectional shape (main cut surface shape) perpendicular to the running direction (longitudinal direction) of the linear pattern is trapezoidal with the bottom part or semicircular or elliptical at the bottom part When the intaglio is used, the top of the conductive convex pattern layer has a flat surface, a semicircle or an ellipse.

When a metal plating layer and a blackening layer are provided by a conventional method on the conductive convex pattern layer made of such a top-shaped conductive composition, the main cut surface shape of the blackening layer surface is also a flat surface or It becomes a semicircle or elliptical shape.
However, the electromagnetic shielding sheet produced in this manner has a large amount of contact with the working part such as a guide roll in the subsequent functional film laminating process, and therefore the amount of the blackened layer worn and peeled off is large. In particular, when a blackened layer of acicular crystals with a good degree of blackening is formed by attenuation due to multiple reflection between the needlelike structures and light diffusion action, the phenomenon is remarkable, and the effect of forming the blackened layer is greatly impaired. .
In addition, when a blackened layer in which the substance itself is light-absorbing is provided on the surface of the metal plating layer by a conventional method, the effect of improving the image contrast under strong light such as external light irradiation is still It is insufficient. That is, the blackened layer has a tendency that the lower the light reflectance, the lower the mobility of free electrons and the lower the conductivity, and hence the electromagnetic wave reflectivity, that is, the electromagnetic wave shielding property. .
Therefore, conventionally, it is difficult to achieve both antireflection performance and electromagnetic wave shielding performance for the blackened layer.

On the other hand, in order to exert an electromagnetic wave shielding function, it is indispensable that the electromagnetic shielding material is electrically connected to the grounded portion at the peripheral portion thereof, and makes electrical contact with the exposed conductive pattern layer. A conductive gasket made of a conductive material such as a sponge-like or rubber-like elastic core material and a metal mesh covering it between the conductive pattern layer and the grounding part in order to ensure sufficient and lower the grounding resistance Is often provided.
However, when a conventional metal plating layer and blackening layer are provided on the conductive pattern layer of the electromagnetic shielding layer, there is a problem that the contact between the conductive gasket and the peripheral portion of the electromagnetic shielding layer is poor and the ground resistance is high. there were.

JP 2001-102792 A Japanese Patent Laid-Open No. 11-174174 International Publication No. 08/149969 Pamphlet

  An object of the present invention is to provide an electromagnetic wave shielding layer having a patterned conductive layer subjected to a blackening treatment, including an electromagnetic wave shielding layer in which the blackened layer is less likely to fall off and has good antireflection against external light, and the periphery of the electromagnetic wave shielding layer For plasma displays in which the conductive pattern layer is connected to the ground via a conductive gasket, and the conductive pattern layer is in good contact with the conductive gasket and the ground resistance is reduced To provide a filter.

  The present invention provides an adhesive layer on the conductive pattern layer side of the portion excluding the peripheral portion of the electromagnetic wave shielding layer having a conductive pattern layer containing conductive particles and a resin binder formed in a predetermined pattern on a transparent substrate. Various functional layers are laminated, and the conductive pattern layer side of the periphery of the electromagnetic wave shielding layer is a filter in which at least a part thereof is connected to the metal frame grounding part via a conductive gasket, The conductive pattern layer of the shielding layer has a metal layer with a corner portion protruding on the surface and a recessed central portion, and a needle-like metal blackening layer formed on the surface of the metal layer. The present invention provides a front filter for a plasma display.

When the top of the conductive pattern is a flat surface and a blackened layer, especially a blackened layer of acicular microcrystals with good blackness, is formed on it, a guide roll or the like is used in the functional film laminating process, which is a subsequent process. Since the contact area with the rigid member is large, the amount of the blackened layer worn out and peeled off is large, but in the present invention in which the top of the conductive pattern layer is recessed, the contact area with the guide roll or the like is small and the surface of the recess Because of the non-contact, the blackened layer on the surface of the concave portion is prevented from being worn out or exfoliated.
In addition, the acicular crystal that forms the blackened layer absorbs and scatters many times while the incident light is multiple-reflected on the surface between the needles, attenuates a lot of light, and the amount of reflected light is greatly increased. Decrease. Moreover, since the acicular crystal is made of a conductive metal, it also has good conductivity (that is, electromagnetic wave shielding).
The present invention provides a conductive gasket in which the conductive pattern on the periphery of the electromagnetic wave shielding layer is flexible and conductive by a throwing effect due to a specific fine structure on the surface of the blackened layer on the surface of the conductive pattern. Sufficiently penetrates into a sufficient contact state, thereby reducing the ground resistance and exhibiting a good electromagnetic wave shielding function.

(A): It is a schematic diagram which shows the structure of the cross section orthogonal to the running direction (longitudinal direction) of the linear pattern of the electromagnetic wave shielding layer in the front filter for plasma displays of this invention. (B): In (A), it is an enlarged view of the electromagnetic wave shielding layer portion in contact with the conductive gasket. It is a schematic diagram which shows the structure of the cross section orthogonal to the running direction (longitudinal direction) of the filament pattern of the electromagnetic wave shielding material of this invention. It is the scanning electron micrograph which looked at the electromagnetic wave shielding material of this invention (Example 1) from the blackening layer side (sequential magnification expansion from (A) to (D)).

As shown in FIGS. 1A and 1B, the front filter for a plasma display according to the present invention is composed of an electromagnetic wave shielding layer 100, an adhesive layer 200, and various functional layers 300, and the conductivity of the peripheral portion of the electromagnetic wave shielding layer. The pattern 10 is in contact with the conductive gasket 400.
Hereinafter, these will be described in detail.

(Electromagnetic wave shielding layer)
The electromagnetic wave shielding layer 100 used in the present invention has a conductive pattern layer 10 containing conductive particles 1 and a resin binder 2 formed in a predetermined pattern on a transparent substrate 20, and the conductive pattern layer. The metal layer 3 is formed on the surface of the metal plate 3 with the end corners of both side edges protruding and recessed in the center, and the surface of the metal layer 3 is formed with a blackened layer 4 of acicular metal. It is what.
Hereinafter, the structure and manufacturing method of the electromagnetic wave shielding layer 100 will be described.

(Transparent substrate)
The transparent substrate 20 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as transparency in the visible region (light transmission), heat resistance, and mechanical strength. A plate-like rigid body such as a transparent inorganic plate or a resin plate may be used. However, a flexible resin film (or sheet) is preferable in consideration of suitability for continuous processing with a roll-to-roll having excellent productivity. The roll-to-roll refers to a processing method in which the material is unwound and supplied from a winding (roll), appropriately processed, and then wound and stored in the winding.

Examples of resins for resin films and resin plates include polyesters such as polyethylene terephthalate, polyethylene naphthalate, ethylene glycol-1,4 cyclohexanedimethanol-terephthalic acid copolymer, and ethylene glycol-terephthalic acid-isophthalic acid copolymer. Examples thereof include resins, acrylic resins such as polymethyl methacrylate, polyolefin resins such as polypropylene and cycloolefin polymers, cellulose resins such as triacetyl cellulose, polycarbonate resins, and polyimide resins. Among them, polyethylene terephthalate is a transparent base material whose biaxially stretched film is preferable in terms of heat resistance, mechanical strength, light transmittance, cost, and the like.
Examples of the transparent inorganic material include soda glass, potassium glass, borosilicate glass, lead glass, and other transparent ceramics such as PLZT, quartz, and the like.

  The thickness of the transparent substrate 20 is basically not particularly limited and is appropriately selected depending on the application. When a flexible resin film is used, it is, for example, about 12 to 500 μm, preferably about 25 to 200 μm. In the case of using a resin or transparent inorganic plate, the thickness is, for example, about 500 to 5000 μm.

In addition, known additives such as an ultraviolet absorber, a colorant, a filler, a plasticizer, and an antistatic agent can be appropriately added to the resin of the transparent substrate as necessary.
The transparent base material may be obtained by performing known easy adhesion treatment such as corona discharge treatment, primer treatment, and ground treatment on the surface.

(Conductive pattern layer)
The conductive pattern layer 10 in the electromagnetic wave shielding layer 100 of the optical sheet of the present invention includes the conductive particles 1 and the resin binder 2, and when the primer layer is formed on the transparent substrate 20 or on the transparent substrate, It is a layer provided in a predetermined pattern on the primer layer.
The pattern shape is a mesh line pattern, and a (mesh or lattice) shape is representative, but a stripe (parallel line group or stripe pattern) shape, a spiral shape, or the like is also used. In the case of a mesh shape, the unit cell shape may be a triangle such as a regular triangle or an unequal side triangle, a square such as a square, rectangle, trapezoid or rhombus, a polygon such as a hexagon or octagon, a circle or an ellipse. Used. In addition, a random mesh pattern or a pseudo-random mesh pattern can be used for the purpose of reducing moire. The line width and the inter-line pitch may be dimensions that are usually employed. For example, the line width can be 5 to 50 μm, and the line-to-line pitch can be 100 to 500 μm. The aperture ratio (ratio of the total area of the openings in the total area of the predetermined pattern formation region) is usually about 50 to 95%.
The line width is required to be further refined in order to obtain a more highly transparent line. From this viewpoint, it is preferably 30 μm or less, particularly 20 μm or less.

In addition, the thickness of the conductive pattern layer 10 varies depending on the resistance value of the conductive pattern layer, but from the balance between the conductive performance and the adhesion suitability of other members on the conductive pattern layer, the central portion ( In the measurement at the top of the projection pattern, it is usually 2 μm or more and 50 μm or less, preferably 5 μm or more and 20 μm or less.
This electroconductive pattern layer 10 can be obtained by forming electroconductive ink containing the electroconductive particle 1 and the resin binder 2 on a base material or a transparent primer layer by the printing method mentioned later.

As the conductive particles 1, the surface of the low resistivity metal particles such as gold, silver, platinum, copper, nickel, tin, and aluminum, or the surface of the high resistivity metal particles, resin particles, non-metallic inorganic particles, etc. is gold or silver. Preferred examples include particles coated with a low resistivity metal such as spherical, spheroidal, regular polyhedral, truncated polyhedral, scaly, disk, dendritic, fibrous, etc. You can choose.
These materials and shapes may be appropriately mixed and used. Since the size of the conductive particles is arbitrarily selected according to the type, it cannot be specified unconditionally. be able to. Although content of the electroconductive particle in an electroconductive composition is arbitrarily selected according to the electroconductivity of an electroconductive particle or the form of particle | grains, for example, among 100 mass parts of solid content of an electroconductive composition, it is electroconductive. The particles can be contained in the range of 40 to 99 parts by mass. In the present specification, the average particle diameter refers to a value measured by a particle size distribution meter or TEM (transmission electron microscope) observation.

As the resin binder 2, any of thermosetting resins, ionizing radiation curable resins, and thermoplastic resins can be used. Examples of the thermosetting resin include resins such as melamine resin, polyester-melamine resin, epoxy-melamine resin, phenol resin, polyimide resin, thermosetting acrylic resin, thermosetting polyurethane resin, and thermosetting polyester resin. Examples of the ionizing radiation curable resin include those described later as the primer material. Examples of the thermoplastic resin include thermoplastic polyester resin, polyvinyl butyral resin, thermoplastic acrylic resin, and thermoplastic polyurethane resin. Can be mentioned. In addition, when using a thermosetting resin, you may add a curing catalyst as needed. When using an ionizing radiation curable resin, a photopolymerization initiator may be added as necessary.
Further, in order to obtain fluidity suitable for filling the concave portion of the plate, these resins are usually used as a varnish dissolved in a solvent. There is no restriction | limiting in particular in the kind of solvent, The solvent generally used for printing ink can be used. The content of the solvent is usually about 10 to 70% by mass, but it is preferably as small as possible within a range where necessary fluidity is obtained. In addition, when an ionizing radiation curable resin is used, a solvent is not necessarily required because it is inherently fluid.

  The conductive pattern layer 10 has, on its surface, at least one side edge, preferably, an end corner of both side edges protrudes, and a metal layer 3 having a recessed central portion is formed, and on the surface of the metal layer. The needle-shaped metal blackening layer 4 is formed. Due to this surface structure, the abrasion and exfoliation of the needle-like crystals on the surface of the blackened layer are improved, the external light antireflection property is good, and the anchoring effect by this structure allows the metal mesh and the adhesive layer to be separated. There is an effect of improving the adhesion.

(Other layers such as primer layer)
In the electromagnetic wave shielding layer of the present invention, it is preferable to provide a primer layer between the transparent substrate 20 and the conductive pattern layer in order to improve the adhesion between the transparent substrate 20 and the conductive pattern layer 10.
The primer layer has good adhesion to both the transparent substrate and the conductive pattern layer, and is a transparent layer for ensuring light transmittance of the opening (conductive pattern layer non-formed portion).
Furthermore, when the conductive pattern layer is formed by a specific intaglio printing method as described later, the primer layer is provided on the transparent substrate in a state where fluidity can be maintained, and contacts the intaglio at the time of intaglio printing. It is a layer that is formed as a layer that is solidified from a liquid state during the process, and is a solidified layer when the final conductive member is formed.

The material constituting such a transparent primer layer is not particularly limited in nature, but in the present invention, a specific intaglio printing method as described below is recommended as a method for forming the conductive pattern layer, and therefore the primer layer is also uncured. A layer formed by coating and curing (solidifying) an ionizing radiation curable resin composition containing a liquid (fluid) ionizing radiation polymerizable compound in a state is suitably used. Hereinafter, this material will be mainly described in detail.
As the ionizing radiation polymerizable compound, monomers and / or prepolymers that are polymerized and cured by a reaction such as crosslinking with ionizing radiation are used.
Examples of such monomers include radically polymerizable monomers such as methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) ) Monofunctional (meth) acrylates such as acrylate, dipropylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) a Polyfunctional (meth) acrylates of various (meth) acrylates such relations and the like. Here, the expression (meth) acrylate means acrylate or methacrylate. Examples of the cationic polymerizable monomer include alicyclic epoxides such as 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, glycidyl ethers such as bisphenol A diglycidyl ether, 4-hydroxybutyl vinyl ether And vinyl ethers, and oxetanes such as 3-ethyl-3-hydroxymethyloxetane.
Such prepolymers (or oligomers) include, for example, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate, and silicon (meth) acrylate as radical polymerizable prepolymers. And various (meth) acrylate prepolymers such as polythiol prepolymers such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. Other examples of the cationic polymerizable prepolymer include novolac type epoxy resin prepolymer and aromatic vinyl ether type resin prepolymer.
These monomers or prepolymers may be used alone or in combination of two or more types of monomers, two or more types of prepolymers, or one type of monomer, depending on the required performance, coating suitability, etc. A mixture of the above and one or more prepolymers can be used.

When ultraviolet rays or visible rays are employed as the ionizing radiation, a photopolymerization initiator is usually added. As a photopolymerization initiator, in the case of a radical polymerizable monomer or prepolymer, a compound such as a benzophenone-based, thioxanthone-based, benzoin-based, or acetophenone-based compound, or in the case of a cationic polymerization-based monomer or prepolymer, Metallocene, aromatic sulfonium and aromatic iodonium compounds are used. These photopolymerization initiators are added in an amount of about 0.1 to 5 parts by mass with respect to 100 parts by mass of the composition comprising the monomer and / or prepolymer.
In addition, as the ionizing radiation, ultraviolet rays or electron beams are typical, but in addition, electromagnetic waves such as visible rays, X-rays and γ rays, or charged particle beams such as α rays and various ion rays are used. You can also.

  The ionizing radiation curable composition may contain a solvent, but in that case, since a drying step is required after coating, it is a type that does not contain a solvent (non-solvent type or solvent-free type) in consideration of cost. preferable.

  The thickness of the primer layer (evaluated by the thickness of the non-formed portion of the conductive pattern layer 10) is not particularly limited, but is usually formed to be about 1 μm to 100 μm after curing. Further, the thickness of the primer layer is usually about 1 to 50% of the total value of the conductive pattern layer and the primer layer (total thickness. Altitude difference between the top of the conductive pattern layer and the surface of the transparent substrate). It is.

  Further, other layers may be formed or processed as necessary. For example, when the durability against rust is insufficient, a rust prevention layer may be provided on the conductive pattern layer. The rust preventive layer can be provided by a conventionally known material and method.

Next, a representative embodiment of the present invention will be exemplified to describe a method for manufacturing an electromagnetic wave shielding layer.
(Method for forming conductive pattern layer)
In this step, the conductive pattern layer is formed using a conductive composition (also referred to as conductive ink or conductive paste) containing conductive particles and a resin binder on one surface of the transparent substrate.
The predetermined pattern of the conductive pattern layer can be formed by various known printing methods such as silk screen printing, flexographic printing, and intaglio printing.
Further, in order to improve the adhesion between the transparent substrate and the conductive pattern layer, when a primer layer is provided between the transparent substrate and the conductive pattern layer, as a method for producing the conductive member, Intaglio printing using a specific primer described in Patent Document 3 is recommended.
The outline of this intaglio printing method will be described below.

  In the intaglio printing method, a conductive composition is applied to a plate surface having a concave pattern (also referred to as a cell) formed in a predetermined pattern on the surface, and then the conductive composition adhering outside the concave section is scraped off. A conductive composition is filled in the recess, and a transparent base material on which one side of the liquid primer layer is formed is pressure-bonded in such a direction that the primer layer is in contact with the intaglio, and the conductive composition and the primer layer in the recess In this state, the primer layer is solidified from a liquid state to a solid state, and then the transparent substrate is separated from the intaglio plate to release the conductive material on the solidified primer layer on the transparent substrate. The composition is transferred and printed.

  After printing, that is, after release, the conductive pattern layer that is still in the liquid state is appropriately subjected to drying operation, heating operation, cooling operation, chemical reaction operation, etc., and the conductive ink is solidified to form the conductive pattern layer. Finalize. Further, the conductive composition may be semi-cured on the plate and completely cured after the release.

In general, in intaglio printing, when conductive ink is supplied to the plate surface, the excess ink is scraped off with a doctor blade or the like and the ink is filled in the plate recesses, a dent is generated on the surface of the filled ink. However, due to the concave portions, there were problems such as poor adhesion to the transparent substrate and a decrease in the transfer rate of the ink onto the transparent substrate.
On the other hand, in the intaglio printing of Patent Document 3, printing is performed through a liquid and fluid primer layer even when a depression (dent) is formed on the upper part of the conductive ink filled in the intaglio depression. The layer can be poured into the recess and brought into close contact, and then the primer layer is solidified, and then the transparent substrate is released from the intaglio, so that the conductivity of the predetermined pattern can be achieved through the primer layer solidified on the transparent substrate. The pattern layer can be formed even with fine lines without occurrence of printing defects such as disconnection and shape defects due to insufficient transfer, and insufficient ink adhesion. Thus, as a result of the primer layer flowing in and filling the depressions formed on the surface of the ink filled in the intaglio depressions, the resulting conductive member has a portion where the thickness of the primer layer is formed on the conductive pattern layer. Becomes thicker than the thickness of the portion where the conductive pattern layer is not formed.

(Metal layer)
In the electromagnetic wave shielding layer in the present invention, the metal layer 3 is formed on the surface of the conductive pattern layer 10 by an electrolytic plating method in order to further improve the conductivity.
The power supply to the conductive pattern layer 10 is performed from an electrode such as a current-carrying roll brought into contact with the surface on which the conductive pattern layer 10 is formed. However, the conductive pattern layer 10 is conductive enough to be electroplated (for example, 100Ω / □ or less), so that electroplating can be performed without any problem. Examples of the material constituting the metal layer 3 include copper, silver, gold, chromium, nickel and the like, which are highly conductive and can be easily plated.
As plating conditions, a bath temperature of 20 to 60 ° C., a current density of 0.001 to 10 A / dm ² , and a plating time of about 1 to 10 minutes are preferable. By increasing the current density, power concentration occurs at the end corners of the conductive pattern layer, and plating is likely to occur. In particular, if the end portion of the conductive pattern layer protrudes before plating, the metal-plated conductive pattern layer has a surface shape in which the end portion protrudes and the central portion is recessed.
In addition, the higher the current density, the more the difference in plating layer growth rate between the corner and the central part, the relatively high current density at the corner and the concave and convex surface shape with the central part of the top recessed. easy. At that time, by making the cross-sectional shape of the conductive pattern layer 10 trapezoidal, rectangular or square as shown in FIG. 1B, the current density at the end portion is relatively increased as compared with the central portion. Can do. In particular, if the end corners of the conductive pattern layer protrude before the plating, this tendency is further strengthened.
Increasing the current density, in addition to this, creates a groove in the surface of the top metal layer, in particular a trough-shaped groove having a branching, meandering or both form as shown in FIG. It becomes easy.
When such a concave groove, in particular, a trough-shaped concave groove having a branching shape, a meandering shape, or both of them is present on the top of the conductive pattern layer, a light beam incident on the concave groove is formed in the concave groove. Attenuates as a result of repeated reflections in a complex path many times. Further, when the light is reflected without being attenuated, it becomes irregular reflection, and the amount of reflected light directed toward the line of sight of the image observer decreases. Therefore, it contributes to the improvement of antireflection of external light such as sunlight and electric light.
In the electromagnetic wave shielding layer of the present invention, the step difference between the end projection and the central recess of the metal-plated conductive pattern layer is about 1 to 3 μm.

(Blackening treatment)
In the present invention, after forming the metal layer, the blackening process is performed to form the blackened layer 4 on the surface of the metal layer.
The blackened layer 4 is composed of a metal needle crystal. The metal constituting the blackened layer may be the same as or different from the metal constituting the metal layer 3, but from the standpoint of reducing the amount of reflected light and achieving high conductivity, the metal having the highest conductivity should be used. For example, gold, silver, platinum, copper, nickel or the like is used.
For example, the blackening treatment is performed by cathodic electrolysis using an electrolytic bath in which copper sulfate pentahydrate and sulfuric acid are dissolved in water. A blackening layer 4 made of a needle-like crystal of metal is formed.
In the roughening treatment, a metal granular projection is deposited by cathodic electrolysis (first layer), and then metal plating is applied thereon to prevent the projection from falling off (second layer) to form a metal coating. The rough surface of the metal which consists of acicular crystals as a whole is made by.
As the blackening treatment (roughening treatment) condition, it is preferable to increase the current density (especially the first layer) because needle crystals are easily formed.
The length of the needle crystal of the blackened layer 4 is about 0.1 to 1 μm, and the diameter is about 1/20 to 1/2 of the length.
Such a needle crystal absorbs and scatters many times while the incident light beam is multiple-reflected on the surface between the needles, attenuates a lot of light, and greatly reduces the amount of reflected light.
As shown in FIG. 1B, when the concave portion with the end portion protruding as described above is formed on the top of the conductive pattern layer 10 and the blackening layer 4 made of needle crystals is further formed on the surface thereof. The effect of preventing reflection of external light is further enhanced by the synergistic effect of the incident light attenuation action of both the recessed portion and the needle crystal.

[Functional layers]
In the present invention, the electromagnetic wave shielding layer 100 is used by being laminated and composited with one or more of various functional layers 300 through the adhesive layer 200.
Examples of the functional layer include an optical functional layer (optical filter layer) such as a near-infrared absorbing layer, a neon light absorbing layer, a toning layer, an ultraviolet absorbing layer, an antireflection layer, an antiglare layer, and a contrast enhancement layer comprising a so-called thin film microlouver layer. Or other functional layers such as a hard coat layer, an impact resistant layer (impact absorbing layer), an antifouling layer, an antistatic layer, an antibacterial layer, and an antifungal layer.
The functional layer is composed of a single layer or a plurality of layers bonded with an adhesive.
The antireflection layer is positioned on the uppermost side (observer side), and the impact resistant layer is positioned on the lower side (PDP side). The other functional layer can be located at any position.
Moreover, a near-infrared absorption layer, a neon light absorption layer, a toning (coloring) layer, and an ultraviolet absorption layer can be formed by containing the absorber in any one or more of the adhesive layers.

[Adhesive layer (adhesive layer)]
The adhesive layer 200 is a layer that has a role of bonding the functional layer 300 and the electromagnetic wave shielding layer 100, or bonding the filter of the present invention to the image display apparatus main body or the image display apparatus substrate, and contains various absorbents. It is a layer that can be various optical functional layers by making it.
The adhesive used for the adhesive layer is basically not particularly limited, and has adhesiveness (adhesive strength), transparency, coating suitability, etc., among the known adhesives, and preferably itself. An uncolored one is appropriately selected. Various natural or synthetic resins can be used, and heat or ionizing radiation curable resin can be applied as a cured form.
The adhesive preferably used is in a form called an adhesive. An example of the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. The acrylic pressure-sensitive adhesive is a polymer containing at least a (meth) acrylic acid alkyl ester monomer. Generally, it is a copolymer of a (meth) acrylic acid alkyl ester monomer having an alkyl group having about 1 to 18 carbon atoms and a monomer having a carboxyl group. In the present invention, (meth) acrylic acid means acrylic acid and / or methacrylic acid.

[Conductive gasket]
In the filter for plasma display of the present invention, the conductive pattern layer 10 at the periphery of the electromagnetic wave shielding layer is connected to the grounding portion through the conductive gasket 400.
This conductive gasket is made of a flexible and elastic core material such as sponge-like or rubber-like polyurethane resin and a conductive material such as a metal mesh covering the conductive material. This is for connecting the layer and a grounding part such as a metal frame in an electrically conductive state. The degree of elasticity of the conductive gasket 400 is such that the entire conductive pattern layer 10 bites into the conductive gasket as shown in FIG. 1B, and the specific surface microstructure on the surface of the conductive pattern layer is within the conductive gasket. It is just enough to bite into.
The conductive gasket is typically a polygonal shape such as a quadrangular or octagonal shape, a circular shape, or an elliptical shape, and the area covering the grounding region is sufficient to obtain a sufficiently low grounding resistance. However, it is preferable to cover the area as wide as possible, and it is more preferable to cover the entire periphery.
In the plasma display filter of the present invention, the conductive pattern on the periphery of the electromagnetic wave shielding layer bites into the conductive gasket due to the throwing effect due to the specific fine structure on the surface of the blackened layer on the surface of the conductive pattern layer. By being in the contact state, the ground resistance is reduced and a good electromagnetic wave shielding function is exhibited.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.

[Example 1]
(Manufacture of electromagnetic shielding sheets)
First, an intaglio was prepared. The intaglio plate mechanically cuts the surface of a cylindrical plate made by coating a copper plating layer on the surface of a hollow iron cylinder, and then electroplating a chromium film on the front surface, A square-pattern mesh pattern-shaped recess having a depth of 20 μm, a line width of 20 μm, and a vertical / horizontal line repetition period of 300 μm was formed to obtain an intaglio for printing. The main cutting plane shape orthogonal to the running direction (longitudinal direction) of the line pattern of the intaglio depression is a trapezoidal shape with a width of the bottom (side closer to the center of the cylinder), and both bottom angles of the bottom corners are Each of the base angles exposed to the cylindrical surface part was 75 degrees, and each base angle of the corners exposed to the cylindrical surface part was 105 degrees, the height of the trapezoid was 20 μm, and the length of the base exposed to the cylindrical surface part of the trapezoid was 20 μm.
Further, at the bottom of the concave part of the trapezoidal main cut surface (corresponding to the top in the conductive pattern layer), the central part protrudes by being curved by 2 μm from the end corner (in the conductive pattern layer, the central part of the top is the end). The shape is curved corresponding to a 2 μm curve and recessed from the corner).
Next, as a transparent substrate, an uncolored transparent biaxially stretched polyethylene terephthalate (PET) film (A4300 manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and a width of 1080 mm × 2000 m was prepared. An ultraviolet curable resin composition for a primer layer was applied and formed on one surface of the transparent substrate so that the dry film thickness was 10 μm. The application method employs a normal gravure reverse roll coating method, and the UV curable resin composition includes 44 parts by mass of a monofunctional monomer composed of 35 parts by mass of an epoxy acrylate prepolymer, 12 parts by mass of a urethane acrylate prepolymer, and phenoxyethyl acrylate. 9 parts by mass of trifunctional monomer composed of ethylene oxide-modified isocyanuric acid triacrylate, and further 3 parts by mass of Irgacure 184 (substance name: 1-hydroxy-cyclohexyl-phenyl-ketone, manufacturer: Ciba Specialty Chemicals) as a photoinitiator We used what we did. The viscosity at this time was about 1300 cps (25 ° C., B-type viscometer), and the primer layer after application showed fluidity when touched, but did not flow down from the PET film.
On the other hand, a silver paste, which is a conductive composition, is applied to the plate surface of the prepared cylindrical intaglio using a pick-up roll, and the conductive composition other than the concave portion is scraped off with a steel doctor blade to conduct electricity only in the concave portion. The composition was filled.
Then, a PET film on which a primer layer in a fluid state is formed between the roll-shaped intaglio plate in a state where the conductive composition is filled in the concave portion and the nip roll, and the pressing force of the nip roll against the roll-shaped intaglio plate ( The flowable primer layer is caused to flow into the recess of the conductive composition existing in the recess by an urging force, and the conductive paste and the fluidity-maintained primer layer are brought into close contact with each other without any gap, and part of the primer Was infiltrated into the conductive composition in the recess.
Next, the intaglio roll was further rotated and irradiated with ultraviolet rays from a high-pressure mercury lamp, and the primer layer in a fluid state made of the ultraviolet curable resin composition was cured. Due to the curing of the primer layer, the conductive paste in the recesses of the intaglio roll is in close contact with the cured primer layer, and then the film is peeled from the intaglio roll by the nip roll on the outlet side, and the conductive composition layer is formed on the primer layer. Was transferred and formed. The film thus obtained is passed through a drying zone at 130 ° C. and dried with hot air for 60 seconds, the solvent in the conductive composition is evaporated, and the conductive conductive composition is deposited on the primer layer. A square-shaped conductive convex pattern layer having a thickness of 19 μm (thickness of the concave portion at the center in the pattern width direction), a line width of 20 μm, and a vertical / horizontal line repetition period of 300 μm was formed. The obtained conductive pattern layer had a shape in which the central portion of the top portion was curved and recessed by 1.5 μm from the end corner portion. In addition, many trough-like concave grooves that branch and meander were formed on the top surface.
The conductive composition contains 93 parts by mass of silver powder having an average particle diameter of about 2 μm as the conductive powder, 7 parts by mass of thermoplastic polyester urethane resin as the resin binder, and 25 parts by mass of butyl carbitol acetate as the solvent. After sufficiently stirring and mixing, it was prepared by kneading with three rolls.

Next, the transparent substrate on which the mesh pattern was formed was plated.
As a plating solution, water (3000 L) is used as a solvent, copper sulfate pentahydrate (75 g / L), sulfuric acid (180 g / L), hydrochloric acid (60 mg / L), and hydrocarbon-based high as an orientation controlling component. A molecular plating additive (40 mL / L) was mixed to prepare a plating solution.
The plating conditions were bath volume (500 mL), stirring (air stirring), bath temperature (25 ° C.), current density (2 A / dm ² ), plating time (5 min), and the film thickness was 2.0 μm. . The coating deposited by plating was annealed at 120 ° C. for 60 minutes to obtain a metal layer made of copper.
Plating is likely to occur where the distance between the portion to be plated and the anode electrode plate is short, and current density is concentrated at the corners, resulting in thick plating. The conductive pattern layer of the present example has a trapezoidal main cut surface and the top end corner is pointed, and the end corner protrudes from the center, so the obtained copper-plated mesh pattern The top part of the surface was a surface shape in which the end corner part protruded and the central part was recessed.

After the plating treatment, a blackening treatment was performed.
The blackening treatment was performed by cathodic electrolysis using an electrolytic bath having the following bath composition and roughening treatment.
(First layer)
Copper sulfate pentahydrate 70g / L
Sulfuric acid 100g / L
Liquid temperature 40 ℃
Current density 40A / dm ²
Electrolysis time 5 seconds Anode Platinum (2nd layer)
Copper sulfate pentahydrate 250g / L
Sulfuric acid 100g / L
Liquid temperature 45 ℃
Current density 20A / dm ²
Electrolysis time 30 seconds Anode Platinum Under the above conditions, the corners of both side edges of the mesh pattern protrude, the central part is recessed, and the top surface is branched and meandering as shown in FIGS. A blackening layer made of needle-like crystals made of copper was formed on the surface of the surface-shaped copper plating layer on which many concave grooves were formed.
Next, the electromagnetic wave shielding sheet on which the blackened layer was formed was cut into a rectangle having a size of 1000 mm × 600 mm. At that time, the angle (bias angle) formed between the long side and the mesh (conductive pattern layer) linear portion running direction was set to 45 degrees.

(Preparation of antireflection layer)
A transparent base material made of a biaxially stretched transparent polyethylene terephthalate (PET) film (A4300, manufactured by Toyobo Co., Ltd.) having a width of 1000 mm and a thickness of 100 μm whose surface was subjected to easy adhesion treatment was set in a paper feeding unit. The antireflective filter in which a high-refractive index layer and a low-refractive index layer were sequentially formed was formed on the easy adhesion treatment surface of the PET film. Here, the high refractive index layer is formed by applying a composition (trade name “KZ7973”, manufactured by JSR Corporation) in which ultrafine zirconia particles are dispersed in an ultraviolet curable resin onto the PET film, followed by drying and curing. The cured product layer has a thickness of 3 μm and a refractive index of 1.69. The low refractive index layer is formed on the high refractive index layer with a fluororesin-based ultraviolet curable resin (trade name “TM086, manufactured by JSR Corporation”). )) Was applied and dried and cured to prepare an antireflection layer that would be a cured product having a thickness of 100 nm and a refractive index of 1.41.

(Manufacture of contrast enhancement layer)
First, on one surface of a transparent substrate as a support comprising a continuous strip-shaped transparent biaxially stretched polyethylene terephthalate (PET) film roll-rolled with a width of 1000 mm and a thickness of 188 μm that has been subjected to easy adhesion treatment on one side,
Epoxy acrylate prepolymer: 40 parts by weight Urethane acrylate prepolymer: 10 parts by weight Monofunctional acrylate monomer composed of phenoxyethyl acrylate: 45 parts by weight Trifunctional acrylate monomer composed of ethylene oxide-modified isocyanuric acid triacrylate: 10 parts by weight Silicon resin release Agent: 1 part by mass Photopolymerization initiator 1-hydroxy-cyclohexyl-phenyl-ketone (trade name Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd.): Liquid UV curable resin composition comprising 3 parts by mass of a mixed solution The product was applied so that the film thickness after curing was 90 μm. Next, the main cut surface shape that is linearly connected in the circumferential direction along the surface direction of the roll mold surface and orthogonal to the extending direction has a height of 85 μm, the length of the base on the plate surface side is 10 μm, and from the plate Roll gold formed with a convex strip group (same shape as the dark colored strip portion and reverse concave / convex) in which a plurality of strip-shaped convex portions having a trapezoidal shape with a base of 4 μm on the far side are arranged in parallel with each other at a period of 45 μm By irradiating ultraviolet rays from a high pressure mercury lamp with the coated ultraviolet curable resin composition sandwiched between the mold and the PET film, the ultraviolet curable resin composition is crosslinked and cured to form a transparent resin layer, Thereafter, by releasing the roll mold, the surface of the transparent resin layer is linearly connected in one direction along the surface direction of the surface of the transparent resin layer, and the main cut surface has a height of 85 μm and a transparent resin. The length of the part corresponding to the longer base on the layer surface side is One surface of the transparent substrate having a transparent resin layer (translucent region) having a concave groove group having a trapezoidal shape with a length corresponding to the bottom of 10 μm and the shorter side on the PET film side of 4 μm Formed on top.
Next, 20 parts by mass of black spherical particles containing carbon black having an average particle diameter (median diameter) of 3.8 μm as a dark colorant in 100 parts by mass of the urethane acrylate prepolymer constituting the resin binder, photopolymerization start A black and liquid ultraviolet curable resin composition prepared by mixing 2 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals) as an agent was prepared. The black liquid composition is applied to the groove of the transparent resin layer, and then the coating film is squeezed with an iron doctor blade to scrape and remove only the black liquid composition outside the groove. The black liquid composition was filled only in the groove, and then this was irradiated with ultraviolet light from a mercury lamp to be crosslinked and cured to form a dark stripe, thereby completing a contrast enhancement layer (microlouver layer). .
It should be noted that the longer bottom surface of the dark colored strip portion 6a after curing has a recessed portion whose surface is recessed toward the shorter bottom side due to the pressure during curing shrinkage and doctor blade scraping. It was. The lowest part of the recessed part was recessed by 3 μm from the surface of the transparent resin layer of the contrast improving layer.

(Preparation of adhesive layer)
Acrylic adhesives (Toyo Ink Co., Ltd., pressure-sensitive adhesive “Olivein” (trade name: BPS6271), solid content 27%) and curing agent BXX5627 (Toyo Ink Manufacturing Co., Ltd.), UV absorber CyasorbUV24 (Cytech) The composition for adhesive layers which mix | blended 4 mass% was prepared.
This pressure-sensitive adhesive layer composition was applied on a release film having a thickness of 38 μm so as to have a thickness of 25 μm, dried at 100 ° C. for 2 minutes, and then the coated surface was laminated with another 38 μm release film, A pressure-sensitive adhesive layer-forming film (1) in which a pressure-sensitive adhesive layer was provided between two release films was produced. Then, it cut | judged to the rectangle smaller 30 mm in length and width than the dimension of the sheet-like electromagnetic shielding sheet.

From 1-H benzotriazole to acrylic adhesive (Toyo Ink Co., Ltd., pressure-sensitive adhesive “Olivein” (trade name: BPS6271), solid content 27%) and curing agent BXX5627 (Toyo Ink Manufacturing Co., Ltd.) The composition for adhesive layers which mix | blended 2 mass% of antioxidant which becomes this was produced.
This pressure-sensitive adhesive layer composition was applied on a release film having a thickness of 38 μm so as to have a thickness of 25 μm, dried at 100 ° C. for 2 minutes, and then the coated surface was laminated with another 38 μm release film, A pressure-sensitive adhesive layer-forming film (2) in which a pressure-sensitive adhesive layer was provided between two release films was produced. Then, it cut | judged to the rectangle smaller 30 mm in length and width than the dimension of the sheet-like electromagnetic shielding sheet.

Acrylic adhesive (Toyo Ink Co., Ltd., pressure-sensitive adhesive "Olivein" (trade name: BPS6271), solid content 27%) and curing agent BXX5627 (Toyo Ink Manufacturing Co., Ltd.) as a near infrared absorbing compound, 0.05% by mass of phthalocyanine compound “IR12” (trade name, Nippon Shokubai Co., Ltd.), 0.02% by mass of phthalocyanine compound “IR14” (trade name, Nippon Shokubai Co., Ltd.) and diimmonium compound “ "IRG-068" (trade name, Nippon Kayaku Co., Ltd.) was blended in an amount of 0.03% by mass. Furthermore, 0.01% by mass of neon light absorber “TAP2” (trade name, Yamada Chemical Co., Ltd.) made of a tetraazaporphyrin-based compound was blended. Further, 0.05% by mass of a toning dye (KAYASET (manufactured by Nippon Kayaku Co., Ltd.)) was mixed and mixed thoroughly to prepare a composition (3) for the pressure-sensitive adhesive layer.
This pressure-sensitive adhesive layer composition was applied on a release film having a thickness of 38 μm so as to have a thickness of 25 μm, dried at 100 ° C. for 2 minutes, and then the coated surface was laminated with another 38 μm release film, An adhesive layer forming film in which an adhesive layer was provided between two release films was produced. Then, it cut | judged to the rectangle of the same magnitude | size as the dimension of the electromagnetic wave shielding sheet which turned into a sheet.

(Preparation of front filter for plasma display)
A functional layer was prepared by laminating the transparent substrate side of the antireflection filter and the opposite surface of the contrast improving layer on the dark color portion forming side through the pressure-sensitive adhesive layer forming film (1) from which the release film was sequentially peeled off.
The surface on the dark color part forming side of the contrast enhancement layer of the functional layer and the surface on the conductive pattern layer forming side of the electromagnetic wave shielding sheet are bonded together via the adhesive layer forming film (2) in which the release film is sequentially peeled off. An optical sheet was obtained. In addition, it bonded together so that the bias angle of the dark color part filament of a contrast improvement layer and the mesh pattern of an electromagnetic wave shielding layer might be set to 42 degrees.
At that time, the electromagnetic wave shielding layer was attached in such a positional relationship that the peripheral portion of the electromagnetic wave shielding layer was exposed as a grounding region without being covered with the functional layer by a width of 15 mm.
The above-mentioned pressure-sensitive adhesive layer-forming film (3) from which the release film has been sequentially peeled is attached to the transparent substrate side of the electromagnetic wave shielding sheet of the optical sheet thus obtained, and the reworking property is applied to the PDP body. An adhesive layer was formed to complete a front filter for plasma display.

  The conductive pattern layer side of the peripheral portion of the electromagnetic wave shielding layer of the front filter for plasma display has a rectangular main cut surface made of a sponge-like polyurethane resin core material and a metal mesh covering the entire periphery. It is in contact with a conductive gasket (manufactured by Taiyo Wire Mesh Co., Ltd., Soft Shield 3500, Part No. 3224 (width 7 mm × thickness 1 mm)), and is connected to a metal frame grounding portion made of aluminum through this.

The electromagnetic wave shielding sheet of Example 1 had a small contact area between the blackened layer and the operation site such as the guide roll in the functional film laminating process as a subsequent process, and the blackened layer was hardly worn or peeled off.
In addition, the PDP front filter of Example 1 and Comparative Example 1 to be described later is displayed in parallel in a room under the same external light presence condition, and both white and black images of the same condition are displayed in parallel on the same PDP. When comparing the luminance ratio (contrast) of both black and white images,
Contrast of Example 1> Contrast of Comparative Example 1.
Then, as schematically shown in FIG. 1B, the conductive pattern on the periphery of the electromagnetic wave shielding layer bites into the conductive gasket due to the anchoring effect due to the specific fine structure on the surface of the blackened layer of the conductive pattern. By being in a sufficient contact state, the ground resistance was reduced and a good electromagnetic wave shielding function was exhibited.

[Comparative Example 1]
At the time of manufacturing the intaglio, a negative photosensitive resist film was applied to the surface of a cylindrical plate material obtained by coating a hollow iron cylindrical surface with a copper plating layer, and the square of the same line width and repetition cycle as in Example 1 was used. The lattice pattern is exposed with an Ar ion laser, and the copper layer is exposed by washing away the unexposed portion on the surface of the cylindrical plate material, and the resist film is left only in the pattern portion of the square lattice. The copper layer of the resist non-formation portion is corroded with an aqueous solution to form a square lattice mesh pattern-shaped recess having a depth of 20 μm, a line width of 20 μm, and a vertical / horizontal line repetition period of 300 μm on the surface of the cylindrical plate. Intaglio was obtained.
A square lattice mesh pattern-shaped recess having a period of 300 μm was formed to obtain an intaglio for printing.
Otherwise, an electromagnetic wave shielding sheet was produced in the same manner as in Example 1.
In the case of the plate-making method, the main cut surface shape of the linear pattern of the concave portion of the plate due to corrosion (etching) is an elliptical shape at the bottom (corresponding to the top of the conductive pattern layer) and the intaglio printing is performed on the plate The cross-sectional shape of the conductive pattern layer was a beautiful semi-elliptical shape with few surface irregularities, and the top portion protruded from the center portion rather than the end portion, and became a smooth curved surface shape convex upward. Even if the plating process was applied to it, the shape of the substrate was affected as it was, resulting in a plating layer shape with a beautiful roundness. Moreover, neither an end corner part nor a ditch | groove was formed in the top surface of the obtained electroconductive pattern layer.
After the plating process, a blackening process was performed. The blackening treatment is performed by immersing the transparent substrate with the mesh pattern and the copper plating layer in a mixed solution of 50 g / L sodium chlorite aqueous solution and 20 g / L sodium hydroxide aqueous solution at a bath temperature of 90 ° C. for 2 minutes. The chemical conversion treatment is performed. Thereby, the copper plating layer surface becomes a copper oxide and is blackened.
Otherwise, the front filter for plasma display of Comparative Example 1 was produced in the same manner as in Example 1.

The electromagnetic wave shielding sheet of Comparative Example 1 had a large contact area between the blackened layer and an operating site such as a guide roll in the functional film laminating process as a post process, and the blackened layer was worn and peeled off.
The adhesion between the electromagnetic wave shielding layer and the pressure-sensitive adhesive layer of the PDP front filter of Comparative Example 1 was poorer than that of the PDP front filter of Example 1.
In addition, the PDP front filter of Example 1 and Comparative Example 1 is displayed indoors in the same external light presence condition, and both white and black images of the same condition are displayed in parallel on the same PDP. When comparing the brightness ratio (contrast) of the image,
Contrast of Example 1> Contrast of Comparative Example 1.
The surface of the blackened layer of the conductive pattern is a beautiful semi-elliptical shape with little surface irregularity, and there is no protrusion at the end corner, and there is no anchoring effect due to the specific fine structure as in Example 1. Therefore, the conductive pattern at the periphery of the electromagnetic wave shielding layer does not bite into the conductive gasket and the contact state between the two is insufficient, so that the ground resistance is not reduced and the electromagnetic wave shielding function is not sufficient.

DESCRIPTION OF SYMBOLS 1 Conductive particle 2 Resin binder 3 Metal layer 4 Blackening layer 10 Conductive pattern layer 20 Transparent base material 100 Electromagnetic wave shielding layer 200 Adhesive layer 300 Various functional layers 400 Conductive gasket

Claims (1)

  Various functions through an adhesive layer on the conductive pattern layer side of the electromagnetic wave shielding layer excluding the peripheral portion of the electromagnetic wave shielding layer having a conductive pattern layer containing conductive particles and a resin binder formed in a predetermined pattern on a transparent substrate Layers, and the conductive pattern layer side of the periphery of the electromagnetic wave shielding layer is a filter in which at least a part thereof is connected to the metal frame grounding part through an electrically conductive gasket. The metal pattern layer is formed with a metal layer with end corners projecting and recessed central parts on the surface, and a needle-like metal blackening layer formed on the surface of the metal layer. A front filter for a plasma display.