JP2010056520A - Optical filter and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical filter which is an electromagnetic-wave shielding filter, low in cost and usable, using aluminum; solves the problem of poor pattern precision of an aluminum pattern formed by chemical etching which results from replacing a material of a metal pattern at a less expensive aluminum using copper, and has superior preventive properties of optical specular reflection. <P>SOLUTION: A filter having electromagnetic-wave shielding properties and the optical specular reflection preventing property includes: a metal pattern layer 2; a flattened layer 5, which consists of a transparent resin and of which the surface is a flat surface, resulting from embedded unevenness of the metal pattern layer 2; and an optical specular antireflection layer 6 laminated on a transparent substrate 1, in this order. In the filter, the metal pattern layer 2 consists of an aluminum layer, the thickness of an oxide film 3 of aluminum, at least on an upper surface (an aluminum layer surface located far from the transparent substrate) is in the range of 0-13 Å. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical filter for various uses, and particularly to a filter having electromagnetic wave shielding properties and optical specular reflection prevention properties, which is suitable for being placed on the front surface of an image display device (display), and a method for producing the same.

  Currently, electromagnetic wave shielding filters are used for applications such as disposing on the front surface of a display, and among them, there are typically plasma display (also referred to as PDP) applications. In an electromagnetic wave shielding filter for a plasma display, a mesh pattern is often used as a metal pattern that achieves both electromagnetic wave shielding performance and light transmittance. A metal pattern (EMI mesh) can be formed by bonding a metal foil to a transparent substrate with a transparent adhesive and then chemically etching the metal foil into a mesh shape by a photolithography method (Patent Documents 1 and 2). ).

As a metal material of the metal foil, there are many documents that are not particularly limited in Patent Documents (Patent Documents 1 and 2). Examples of metals include high conductivity, such as aluminum (Patent Document 2), in addition to copper. However, in actuality, the EMI mesh of the electromagnetic wave shielding filter distributed in the market uses only copper, specifically, copper foil, and does not use aluminum foil and has not been put into practical use.
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).

  In addition, the display filter is required to have an electromagnetic wave shielding property and an optical filter function such as antireflection of extraneous light. When an antireflection agent is applied to a transparent substrate on which a metal pattern is formed, the metal pattern layer and the transparent substrate are used. As a result, uneven coating of the antireflective agent and mixing of bubbles occur, and the antireflection effect becomes insufficient. In order to solve this problem, a transparent flattening layer for flattening the unevenness between the metal pattern layer and the transparent substrate is provided by coating, and an antireflection layer having a lower refractive index than the flattening layer is provided on the upper surface. It has been proposed to provide the film by coating or sheet lamination (Patent Document 3).

JP 2003-318596 A Japanese Patent No. 3388682 JP-A-11-337702

In recent years, the promotion of the spread of image display devices (displays) has been hampered by expensive electromagnetic shielding filters, and in order to reduce the cost of electromagnetic shielding filters, the use of aluminum foil that is less expensive than copper foil is considered. It is done.
Therefore, we studied electromagnetic wave shielding filters using aluminum foil cheaper than copper foil as the metal material of the metal pattern (EMI mesh) with the aim of lowering the cost. Has the following problems to be solved. The following problems are not noticeable when the line width and thickness of the pattern are about 100 μm or more. It has also been found that the line width and thickness of the pattern are particularly manifested when the line width and thickness are reduced to about 10 to 20 μm or less in order to pursue transparency for high-quality display applications.

(A) Aluminum itself has high activity, and an aluminum oxide film is present on the surface, which becomes a corrosion-resistant film and inhibits chemical etching.
(B) When a portion of the oxide film in the region in contact with the etching solution is removed, the aluminum itself is chemically active, so that the removed portion is rapidly etched against the portion that has not yet been removed. Therefore, uniform and stable etching is difficult.
(C) As a result of the above (a) and (b), the contour of the line portion of the metal pattern has a zigzag shape. In other words, aluminum is inferior in the pattern accuracy of the line compared to the case of copper foil.

As a result, a fine pattern (for example, a line width of 10 to 20 μm and a pattern thickness of about 10 to 20 μm) required by the image display device cannot be obtained as compared with the copper foil. Then, the unevenness leads to unevenness in the area ratio of the opening that realizes light transmittance, leading to unevenness in the surface of the display screen, and disconnection leads to deterioration in electromagnetic wave shielding performance.
Further, adding one flattening layer in order to prevent uneven coating of the antireflective agent and mixing of bubbles leads to a rise in processing cost and a decrease in production efficiency due to an increase in processing time and the number of processes.

That is, the object of the present invention is to eliminate the poor pattern accuracy of an aluminum pattern formed by chemical etching, which occurs when the material of the metal pattern is changed from copper to inexpensive aluminum, and to provide an inexpensive and practical electromagnetic wave using aluminum. An object of the present invention is to provide an optical filter that is a shielding filter and has excellent optical specular reflection prevention.
In addition to this, it is an object to provide an optical filter having excellent optical mirror surface antireflection properties without coating unevenness and mixing of bubbles.
Another object of the present invention is to provide a method for manufacturing an optical filter without increasing the processing cost and reducing the production efficiency due to the increase in processing time and the number of processes.

  Therefore, the present invention provides a metal pattern layer, a flattening layer made of a transparent resin, filling the unevenness of the metal pattern layer to make the surface flat, and an optical specular antireflection layer in this order on a transparent substrate. The filter is a laminated filter, wherein the metal pattern layer is an aluminum pattern layer, and the thickness of the aluminum oxide film on at least the upper surface of the aluminum pattern layer (the surface of the aluminum layer far from the transparent substrate) is 0 to Provided is a filter that is 13 mm and a method for manufacturing the same.

  In this way, by defining the thickness of at least the aluminum oxide film on the upper surface side to be thin, stable etching is possible when the aluminum pattern is formed by chemical etching, and the etching quality is improved. In addition, the defect that causes disconnection is eliminated, the pattern accuracy is improved, and as a result, variations in electromagnetic shielding properties (surface resistance value) and haze (cloudiness value) can be avoided. As a result, an electromagnetic wave shielding filter that is inexpensive in terms of material can be put into practical use by using aluminum that is less expensive than copper.

According to the filter of the present invention, even when aluminum which is cheaper than copper is used for the metal pattern, the line contour zigzag and disconnection at the time of chemical etching formation are eliminated, the pattern accuracy is improved, and electromagnetic wave shielding ( Variations in the surface resistance) and haze increase can be avoided, and an inexpensive electromagnetic wave shielding filter can be put into practical use.
Moreover, since the aluminum oxide film can be chemically etched as it is in terms of production, an additional removal process of the oxide film is unnecessary, and the manufacturing process is not complicated and the cost is increased.
In addition, the filter of the present invention is provided with a flattened layer whose surface is flat by filling the unevenness of the metal pattern layer, and an optical specular antireflection layer, thereby providing excellent optical specular antireflection as well as electromagnetic shielding properties. Therefore, the optical filter is suitable for a display.

It is typical sectional drawing which shows an example of the optical filter of this invention. It is explanatory drawing when manufacturing the optical filter of this invention by the lamination method.

FIG. 1 is a conceptual cross-sectional view showing a layer configuration of one form of an optical filter according to the present invention.
In the case of the figure, an aluminum pattern 2 is formed on one surface of the transparent substrate 1, and the aluminum pattern 2 has an upper surface (surface far from the transparent substrate 1) and a lower surface (on the side close to the transparent substrate 1). (Surface) has an oxide film 3 of aluminum, and the thickness of the oxide film on at least the upper surface is in the range of 0 to 13 mm. And in the example of the figure, this aluminum pattern 2 is adhered and fixed to the transparent base material 1 by the transparent adhesive layer 4 on the surface of the oxide film 3 on the lower surface side and laminated. The transparent adhesive layer 4 is formed on the entire surface of the transparent substrate 1 including the opening of the aluminum pattern.
The optical filter according to the present invention comprises a flattening layer 5 made of a transparent resin and having a flat surface on the surface of the aluminum pattern 2 having the oxide film 3 on the surface. The antireflection layer 6 is laminated in this order. In FIG. 1, the upper side is the viewer (viewer) side, and the lower side is the image display apparatus side.
Hereinafter, the configuration of the optical filter of the present invention will be described in detail.

[Transparent substrate]
The transparent substrate 1 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as transparency in the visible region (light transmittance), heat resistance, and mechanical strength, such as glass and ceramics. 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, potash glass, borosilicate glass, lead glass, and other transparent ceramics such as PLZT and quartz.

  The thickness of the transparent substrate 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.

[Aluminum pattern]
The aluminum pattern 2 is a pattern layer formed of aluminum, and the layer itself is opaque, but by providing a pattern in which an unformed portion of the layer such as an opening is provided, both electromagnetic wave shielding performance and light transmittance are achieved. Layer. The aluminum pattern 2 of the present invention has an aluminum oxide film 3 having a specific thickness range of 0 to 13 mm on at least the upper surface thereof. Note that 1Å = 0.1 nm.

  Aluminum in the aluminum pattern is mainly composed of aluminum, and may be aluminum alloy in addition to aluminum pure metal. These are collectively referred to as aluminum in the present invention. However, since the conductivity decreases when the purity of aluminum is low, the purity is shielded against electromagnetic waves. Higher is preferable in terms of performance, and aluminum having a purity of 99.0% or more is preferable. The aluminum pattern using aluminum having a purity of 99.0% or more is made of a foil conforming to the aluminum foil defined in JIS H4160 (aluminum and aluminum alloy foil) and JIS H4170 (high purity aluminum foil). It can be formed by using it.

  Note that the aluminum pattern is not formed from an aluminum foil, but an aluminum pattern formed from an aluminum vapor deposition film formed by vapor deposition, for example, a vacuum vapor deposition method, on a transparent substrate may be used.

  The thickness of the aluminum pattern may be appropriately selected from the viewpoints of electromagnetic wave shielding performance, processability, mechanical strength, and the like, specifically 1 to 100 μm, preferably 5 to 20 μm, more preferably 8 to 15 μm. If the thickness is thin, electromagnetic wave shielding performance, mechanical strength and the like are lowered, and if the thickness is thick, workability is lowered.

  The shape of the aluminum pattern in plan view is, for example, a known pattern in which both electromagnetic wave shielding performance and light transmittance such as a mesh shape and a stripe shape are compatible. Among them, a mesh shape and a square lattice shape are typical, and in addition, examples of the lattice shape include a rectangular lattice, a rhombus lattice, a hexagonal lattice, and a triangular lattice. The mesh has a plurality of openings having these shapes, and the openings are line portions (line portions or line portions) that define the openings. The line part is usually a line having a uniform width, and usually the opening part and the opening part are all the same shape and the same size.

  In addition, the above pattern is a solid pattern in which an opening is not provided for grounding continuity in the periphery of the four sides that does not affect the image display of the electromagnetic wave shielding filter in a display application, or a grounding area with a small occupied area ratio. May be provided around an internal image display area having an opening.

  The line width of the line portion of the pattern is, for example, 5 to 50 μm, and is 5 to 30 μm, more preferably 5 to 20 μm, from the standpoint of the effect of the present invention. The line interval (pitch), which is a line repetition period, is, for example, 100 to 500 μm.

(Pattern formation)
In order to form the pattern of the aluminum pattern, it can be formed by chemical etching after laminating an aluminum layer such as an aluminum foil on the transparent base material before pattern formation.
For pattern formation of the resist pattern during chemical etching, a known pattern formation method such as a photolithography method (pattern exposure method) or a printing method may be appropriately selected. Among these, the photolithography method is a preferable method compared to the printing method in that a highly accurate pattern such as a line width required for the electromagnetic wave shielding filter and its uniformity can be stably formed.

A known etching solution may be appropriately selected and used as an etching solution for chemically etching the aluminum pattern. For example, an acidic etching solution containing ferric chloride.
The etching is performed including the aluminum oxide film in the resist pattern non-formation portion on the upper surface of the aluminum layer. It is not particularly necessary to remove the aluminum oxide film on the upper surface as a pretreatment for etching.
Then, the aluminum oxide film 3 on the upper and lower surfaces corresponding to the resist pattern forming portion remains as the oxide film 3 on the upper and lower surfaces of the aluminum pattern 2.

[Aluminum oxide film]
An aluminum oxide film is a layer containing an aluminum oxide. When an aluminum pattern is formed using an aluminum foil, the aluminum oxide film exists on both the top and bottom surfaces of the foil. When the pattern is formed, the thickness of the first etched side, that is, the upper surface side is defined. The upper limit of the thickness of the aluminum oxide film on at least the upper surface of the aluminum pattern is 13 mm, preferably 12 mm, more preferably 10 mm, and still more preferably 8 mm.
By setting the upper limit of the thickness of the aluminum oxide film on at least the upper surface as described above, stable chemical etching is possible even if the oxide film is still present, and copper is changed to inexpensive aluminum. The pattern accuracy defect can be avoided.

  By the way, normally manufactured aluminum foil is manufactured by a rolling method, and manufactured and stored at normal temperature (20 ° C., around 50% RH), such as aluminum ingot rolling process, foil manufacturing process through annealing process, and subsequent storage in air. By doing so, an active aluminum irreversibly forms an oxide film of aluminum on the surface, but it does not become a thin oxide film as in the present invention, but is thicker than 15 mm, usually about 20 to 100 mm. It becomes an oxide film.

In addition, the lower limit of the thickness of the aluminum oxide film on the upper surface of the aluminum pattern is 0 (zero), that is, no oxide film may be present from the viewpoint of not inhibiting chemical etching.
However, the aluminum oxide film is said to be a passive film, and during the process of processing, transporting and storing the aluminum foil, oxidation or corrosion progresses (inadvertently or undesirably) inside the aluminum foil. In this respect, an oxide film as a dense aluminum passivating film having a thickness of about 2 to 3 mm may be formed.

  In addition, the aluminum pattern in which the aluminum oxide film does not exist on the upper (lower) surface is formed on the transparent substrate in vacuum and in an inert gas on the transparent substrate, and the aluminum layer is formed before the oxide film is formed. This can be achieved by coating the upper surface with a resin to block the oxidation reaction. Thereafter, when a predetermined pattern is formed by chemical etching, an aluminum pattern having no aluminum oxide film on the upper (lower) surface is obtained.

  There are various ways to reduce the thickness of the aluminum oxide film as described above, but when aluminum foil is used for the aluminum pattern, the aluminum foil is made by rolling, and then manufactured by annealing. However, it can adjust to the target thickness by adjusting rolling conditions and annealing conditions.

  For example, when removing the rolling oil adhering to the surface of the aluminum foil after rolling during annealing, the gas composition of the annealing atmosphere is controlled so that the surface is not oxidized (the oxygen concentration is lowered), aluminum There are methods such as removing the aluminum oxide film on the foil surface with chemicals. Although there is a method of not annealing, rolling oil is not preferable because it adversely affects the photolithography method.

  The thickness of the aluminum oxide film is measured by X-ray photoelectron spectroscopy (XPS), which is a kind of Hunter Hall method and X-ray fluorescence analysis.

The aluminum oxide film is usually formed on both the front and back surfaces of the foil, that is, both the upper surface and the lower surface from the foil manufacturing process. Among these, since it is the oxide film on the upper surface that affects the chemical etching for pattern formation of the aluminum pattern, the present invention defines a specific thickness (thinness) for at least the aluminum oxide film on the upper surface. In addition, the aluminum oxide film on the bottom surface usually has a negligible contribution to the generation of mesh shape burrs during chemical etching compared to the aluminum oxide film on the top surface, so it is not necessary to specify it from the point of pattern accuracy. Absent. However, if the film thickness is too large, the mesh shape due to the aluminum oxide film remaining in the opening may be adversely affected, and the transparency of the opening may be reduced. For this reason, it is recommended that the aluminum oxide film on the lower surface is preferably less than the minimum visible light wavelength of 380 nm, more preferably 200 nm or less. For example, the thickness of the aluminum oxide film on the lower surface is set to 0 to 13 mm as in the upper surface. As one embodiment of the present invention, by adjusting the thickness of the aluminum oxide film on the lower surface before chemical etching and the processing conditions for chemical etching, the pattern opening has a minimum wavelength of visible light of less than 380 nm (for example, 3 to 3). A transparent aluminum oxide film having a thickness of 13 Å) can be left to protect the transparent adhesive layer or transparent substrate exposed to the opening during chemical etching from coloring by the corrosive liquid.
However, if the lower surface aluminum oxide film has the same thickness as that of the upper surface oxide film, the thickness of the lower surface aluminum oxide film is defined to be the same as the thickness of the upper surface aluminum oxide film. be able to.

(Blackening treatment layer)
The aluminum pattern may have a blackened layer on the surface.
The blackening treatment layer is a layer for improving external light absorption and image contrast by suppressing light reflection by the aluminum pattern and the oxide film on the surface. The blackening treatment layer is provided when external light absorption and image contrast improvement are required. When there is an oxide film on the surface or surface of the aluminum pattern, the blackening treatment layer is a layer that is provided on the surface of the film to reduce the light reflectance.

  Here, the surface refers to a surface such as an upper surface, a lower surface, or a side surface. The surface on which the blackening treatment is performed to form the blackening treatment layer may be surfaces according to requirements, such as only the upper surface, the upper surface and both side surfaces, only the lower surface, and all surfaces of the upper surface, both side surfaces, and the lower surface. This is the same as a known blackening process. Among these, the surface in contact with the transparent adhesive in the presence of the transparent adhesive layer is the lower surface. Further, in order to use the electromagnetic wave shielding filter with the upper surface side of the observer side, it is preferable to form a blackening treatment layer on at least the upper surface, more preferably on both side surfaces and the lower surface on the image display element side. A blackening treatment layer is preferably formed.

  As the blackening treatment layer, any known electromagnetic shielding filter may be employed as appropriate. For example, as the blackening treatment layer, an inorganic material such as a metal, an organic material such as a black resin, or the like can be used. The inorganic material is, for example, a metal compound such as a metal or an alloy, a metal oxide, or a metal sulfide, and can be formed by a known blackening process such as a plating method. Moreover, as black resin, it can form as a layer which contained the black coloring agent in resin, for example.

[Transparent adhesive layer]
The transparent adhesive layer 4 is a layer for fixing the aluminum pattern to the transparent substrate. For example, when the aluminum pattern is formed from an aluminum foil, the transparent adhesive layer 4 is used for bonding and fixing the aluminum foil to the transparent substrate. . The transparent adhesive layer can be omitted when an aluminum pattern is formed from an aluminum layer directly laminated on a transparent substrate by aluminum vapor deposition.

  The transparent adhesive layer may be a transparent adhesive so as not to impair the light transmission through the openings of the aluminum pattern, and a known transparent adhesive may be used as appropriate. For example, urethane adhesive, acrylic adhesive, epoxy adhesive, rubber adhesive, and the like. Among these, urethane adhesives, for example, two-component curable urethane adhesives are preferable in terms of adhesive strength. As the two-component curable urethane-based adhesive, an adhesive using a polyol as a main agent and a polyisocyanate compound as a curing agent can be used. Examples of the polyol include acrylic polyol, polyester polyol, polyurethane polyol, polyether polyol, and polyester polyurethane polyol. The polyisocyanate compound is, for example, an aromatic isocyanate compound such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, hydrogenated tolylene diisocyanate, isophorone diisocyanate, etc. Examples thereof include aliphatic to alicyclic isocyanate compounds. These isocyanate compounds can also be used in the form of multimers or adducts. A plurality of polyols and polyisocyanate compounds may be used.

  The transparent adhesive layer can be formed by applying a transparent adhesive to one or both of the aluminum foil and the transparent substrate by a known forming method, and then laminating them with the adhesive interposed therebetween. The forming method includes a coating method and a printing method.

[Planarization layer]
The metal pattern layer has a concavo-convex surface (the opening is concave and the wire ridge is convex). And, since the material for forming the optical specular antireflection layer is generally poor in performance to fill the unevenness and flatten the surface, when the optical specular antireflection layer is formed directly on the metal pattern layer, When the optical specular antireflection layer does not completely fill the unevenness of the metal pattern layer, the unevenness remaining on the surface of the optical specular antireflection layer scatters image light. Further, even when the optical specular antireflection layer is completely filled with the unevenness of the metal pattern layer, the air in the recesses of the metal pattern layer remains without being sufficiently replaced and becomes bubbles. The image light is scattered to cause the image to become cloudy, and to reduce the image quality such as a decrease in the contrast of the image and a blurring of the outline at the edge of the image. In order to prevent this, a planarizing layer is interposed between the metal pattern layer and the optical specular reflection preventing layer.

The flattening layer is a layer that fills the unevenness of the metal pattern layer and has a flat surface, and is made of a transparent resin. The resin is appropriately selected from thermoplastic resins, thermosetting resins, ionizing radiation curable resins, and the like.
As the thermoplastic resin, acrylic resin, thermoplastic polyester resin, vinyl chloride-vinyl acetate copolymer, cellulose resin, polyolefin resin, and the like are used.
Here, examples of the acrylic resin include polymethyl (meth) acrylate, polybutyl (meth) acrylate, methyl (meth) acrylate-ethyl (meth) acrylate copolymer, and methyl (meth) acrylate-butyl (meth) acrylate copolymer. Polymer, methyl (meth) acrylate-styrene copolymer, methyl (meth) acrylate-ethylene copolymer, methyl (meth) acrylate-2hydroxyethyl (meth) acrylate copolymer, methyl (meth) acrylate-2hydroxy 3 Examples include phenyloxypropyl (meth) acrylate copolymer, methyl (meth) acrylate-2hydroxyethyl (meth) acrylate-styrene copolymer, and the like (where (meth) acrylate means acrylate or methacrylate).
Examples of the thermoplastic polyester resin include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and 1,4 cyclohexane dimethanol, and many such as terephthalic acid, isophthalic acid, maleic acid, fumaric acid, and adipic acid. Examples include those obtained by condensation polymerization with a basic acid.
Examples of the vinyl chloride-vinyl acetate copolymer include a vinyl chloride-vinyl acetate copolymer having a vinyl acetate content of about 5 to 20% by mass and an average degree of polymerization of about 350 to 900. If necessary, it may further be copolymerized with carboxylic acids such as maleic acid, fumaric acid and (meth) acrylic acid.
Examples of the cellulose resin include nitrocellulose (nitrified cotton), cellulose acetate, and cellulose acetate propionate.
Examples of the polyolefin resin include polyethylene, polypropylene, polymethylpentene, and cyclic polyolefin.
As the thermosetting resin, for example, a thermosetting urethane resin, a thermosetting unsaturated polyester resin, an epoxy resin, or a phenol resin is used.
Here, as the urethane resin, for example, (polyvalent) polyol and (polyvalent) isocyanate are reacted. Examples of the (polyvalent) polyol include acrylic polyol, polyester polyol, polyether polyol, polyurethane polyol and the like. (Polyvalent) isocyanates include 2,4 tolylene diisocyanate, xylene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate and other aromatic isocyanates, 1,6 hexamethylene diisocyanate, hydrogenated tolylene diisocyanate, isophorone diisocyanate aliphatic (or fat Cyclic) isocyanates.
As the ionizing radiation curable resin, a monomer (monomer) that is polymerized and cured by a reaction such as crosslinking with ionizing radiation, or a prepolymer or an oligomer is used. As the monomer, for example, a radical polymerizable monomer, specifically, 2-ethylhexyl (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) Examples thereof include various (meth) acrylates such as acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. Examples of the prepolymer (or oligomer) include radically polymerizable prepolymers, specifically, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, triazine (meth) acrylate, and the like. (Meth) acrylate prepolymers, polythiol prepolymers such as trimethylolpropane trithioglycolate, pentaerythritol tetrathioglycolate, and unsaturated polyester prepolymers. Other examples include cationically polymerizable prepolymers such as novolac epoxy resin prepolymers and aromatic vinyl ether resin prepolymers.
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.
As the photopolymerization initiator, in the case of a radically polymerizable monomer or prepolymer, a benzophenone-based, acetophenone-based, thioxanthone-based, benzoin-based compound, etc., or in the case of a cationic polymerization-based monomer or prepolymer, , Metallocene-based, aromatic sulfonium-based and aromatic iodonium-based 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.
The ionizing radiation is typically ultraviolet rays or electron beams, but in addition, electromagnetic waves such as visible rays, X rays and γ rays, or charged particle rays such as α rays and various ion rays are used. You can also.

  In the constituent materials of these planarization layers, additives can be appropriately added as necessary. Examples of the additive include a heat stabilizer, a radical scavenger, a plasticizer, a surfactant, an antistatic agent, an antioxidant, an ultraviolet absorber, an infrared absorber, a dye (colored dye, colored pigment), and an extender pigment. And a light diffusing agent.

  The thickness of the flattening layer is such that the thickness of the metal pattern opening that is the maximum thickness is equal to or greater than the thickness of the metal pattern layer in order to fill the unevenness of the metal pattern layer and make the surface flat. Preferably, the thickness is set to be about 1 to 5 μm thicker than the thickness of the metal pattern layer.

(Formation method)
As a method for forming the planarization layer, the resin is usually softened or fluidized to such an extent that the unevenness of the metal pattern layer can be filled. More preferably, in a liquid state, it is positioned between the metal pattern layer formed on the transparent substrate and the optical specular antireflection layer, and is applied so as to fill the irregularities of the metal pattern layer. . The fluidity here is not limited to Newtonian viscosity, but may be dilatancy or thixotropic non-Newtonian viscosity. The viscosity should be sufficient to fill the unevenness of the metal pattern layer, and is appropriately adjusted according to the processing conditions and the degree of the unevenness during coating or transfer (when the flattening layer is formed by transfer). .
The object to be coated is applied only to the uneven side of the metal pattern layer, applied only to the optical mirror surface antireflection layer side, or divided and applied to both the uneven side of the metal pattern layer and the optical mirror surface antireflection layer side. Either of these is possible. After coating, the liquid film is solidified or cured to form a flattened layer.
In addition, it is also possible to select a form in which a flattening layer previously formed by coating on a transfer sheet is transferred to a metal pattern layer alone or together with an optical specular reflection preventing layer.

In the form in which the planarizing layer is directly coated on the uneven surface of the metal pattern layer to form it, if it is a monomer or prepolymer that is liquid at room temperature, it is used as the coating liquid. If necessary, dilute to an appropriate viscosity with a diluent such as an organic solvent. Such a coating solution is applied onto the metal pattern layer. After that, if the solvent is diluted, the solvent or the prepolymer is removed by heating, ionizing radiation irradiation or the like after drying and removing the solvent. The polymer is cross-linked or polymerized to be cured (solidified) to form a flattened layer. In the case of the said thermosetting resin and ionizing radiation curable resin, it is based on this form exclusively. As the coating method, roll coating, gravure roll coating, bar coating, curtain flow coating, die coating, comma coating, spray coating or the like is applied.
Among the thermoplastic resin or the ionizing radiation curable resin, particularly those having a high molecular weight and an uncured product in a solid state even at room temperature, once solvent-diluted and formed on a substrate, the solvent is added. Resin consisting of a polymer that is solid at room temperature as in the case of using an uncured product of the ionizing radiation curable resin obtained by drying and removing (this form is also included in the thermoplastic resin). In this case, it is heated to the melting point or the melting temperature or higher to be liquefied (also referred to as melting), or is made into a solution with an organic solvent. Such a liquid or solution is applied onto the metal pattern layer, and then cooled to a melting point or a melting temperature or lower, or the solvent is dried and solidified to form a flattened layer. In particular, in the case of the above-mentioned thermoplastic resin, it is exclusively based on this form. As a coating method in the case where a thermoplastic resin is melted and used, a melt extrusion coating method from a T die is a typical one. Of the thermoplastic resins, in particular, when an uncured material in the solid state at room temperature of the ionizing radiation curable resin is used for the adhesive layer, the adhesive layer is heated and liquefied, cooled and solidified once. After the bonding is completed, it is preferable to further perform irradiation with ionizing radiation or curing. By curing in this manner, the adhesive layer that has been cooled and solidified is improved in adhesive strength, strength, and heat resistance, and the adhesive is not melted or softened again even when heated again.
On the other hand, in a form in which the planarizing layer is transferred and formed on the uneven surface of the metal pattern layer, a transfer sheet having a configuration in which the planarizing layer is previously formed as a transfer layer on a release substrate as described later. Keep it easy. Next, the transfer sheet is pressure-bonded onto the metal pattern layer so that the surface on the flattening layer side of the transfer sheet is in contact with the metal pattern layer side. If the planarization layer has fluidity at that time, it remains in that state, and if the planarization layer does not have fluidity at that time, the planarization layer is heated and softened or melted. Fluidize by such methods. Next, the fluid flattening layer is filled in the irregularities of the metal pattern layer, and is replaced with air in the irregularities. During this process, the side surface opposite to the metal pattern side of the flattening layer comes into contact with the flat surface of the release substrate and the deformation is restricted, so that the flat surface is kept flat. Thereafter, the planarizing layer is left on the metal pattern layer side, and only the peeling substrate is peeled off.
In this transfer mode, an optical specular antireflection layer is further formed on the release substrate as a transfer layer;
If it is set as the structure of a peeling base material / optical mirror surface antireflection layer / flattening layer, an optical mirror surface antireflection layer can be formed simultaneously with the flattening layer on the metal pattern layer, which is preferable. In such a transfer form, the planarization layer also functions as an adhesive layer that adheres the transfer layer to the transfer target.

[Optical mirror antireflection layer]
One of the following antiglare layers or antireflection layers is selected. Alternatively, both can be provided in combination.

(Anti-glare layer)
An antiglare layer (Anti Glare layer, abbreviated as AG layer) is formed by roughening the light incident surface or dispersing light diffusing particles in the layer in order to scatter or diffuse extraneous light. Is. In this roughening treatment, a method of forming fine irregularities directly on the surface of the substrate by sandblasting or embossing or the like; roughening the surface of the substrate; in a resin binder that is cured by radiation or heat or a combination thereof; A method of providing a roughened layer with a coating film containing an inorganic filler such as silica or an organic filler such as resin particles as light diffusing particles, and having microscopic irregularities corresponding to the filler protruding on the coating film surface; And a method of forming a porous film having a sea-island structure on the substrate surface. As the resin of the resin binder, a curable acrylic resin, an ionizing radiation curable resin, or the like is preferably used in the same manner as the hard coat layer described below because surface strength is desired as the surface layer.
In the case where the light diffusing particles are dispersed in the layer, a refractive index difference (preferably 0.14 or more) is provided between the filler dispersed in the coating film and the coating film binder resin. Select materials to have. In the case of this form, the coating surface may be a flat surface (smooth surface).
The thickness of the antiglare layer is not particularly limited, but is preferably 0.07 μm or more and 20 μm or less.
Further, when the average interval between the irregularities of the antiglare layer is Sm, the average inclination angle of the irregularities is θa, and the ten-point average roughness of the irregularities is Rz, Sm is 60 to 250 μm and θa is 0 It is preferable that the angle is 3 ° to 1.0 ° and Rz is 0.3 to 1.0 μm.
In addition, said Sm, (theta) a, and Rz are based on JISB06011994, For example, it can measure with a surface roughness measuring device ("SE-3400" by Kosaka Laboratory).

(Antireflection layer)
The antireflection layer (Anti Reflection layer, abbreviated as AR layer) is a single layer of a low refractive index layer, or a low refractive index layer and a high refractive index layer, and the low refractive index layer is positioned in the uppermost layer. A multilayer structure in which the layers are alternately laminated is generally used, and can be formed by a dry film formation method such as vapor deposition or sputtering, or by using a wet film formation method such as coating.
Here, the high (low) refractive index layer means that the refractive index of the layer is relatively high compared to a layer adjacent to the layer (for example, a planarization layer or a low (high) refractive index layer) ( Means low).
When the antireflection layer is further provided with an abrasion resistance function, it is formed by appropriately using a material having high hardness as described in the section of the following abrasion resistance function (hard coat) layer.

In order to improve the antireflection effect, in principle, the refractive index of the low refractive index layer is preferably set to the square root of the refractive index of the layer immediately below. For example, if the layer immediately below has a refractive index of 1.50, the refractive index of the low refractive index layer is 1.23, and if the layer directly below has a refractive index of 2.10, the refractive index of the low refractive index layer is 1.45. It is. Even if this value cannot be completely matched, it is designed to be as close to this value as possible.
Examples of the material having such a low refractive index include LiF (refractive index n = 1.36), MgF ₂ (refractive index n = 1.38), 3NaF · AlF ₃ (refractive index n = 1.4), AlF ₃ (Refractive index n = 1.37), Na ₃ AlF ₆ (refractive index n = 1.33), NaF (refractive index n = 1.33), CaF ₂ (refractive index n = 1.44), Na ₃ AlF ₆ Inorganic low-reflective material in which inorganic material such as (refractive index n = 1.33), SiO ₂ (refractive index n = 1.45) is finely divided and contained in acrylic resin or epoxy resin, fluorine-based material -Organic low reflection materials, such as a silicone type organic compound, a thermoplastic resin, a thermosetting resin, and a radiation curable resin, can be mentioned.

  Further, fine particles having voids may be used for the low refractive index layer. The fine particles having voids form a structure in which fine particles are filled with gas and / or a porous structure containing gas, and are in inverse proportion to the gas occupancy ratio in the fine particles compared to the original refractive index of the fine particles. It means fine particles having a reduced refractive index. The present invention also includes fine particles capable of forming a nanoporous structure inside and / or at least part of the surface depending on the form, structure, aggregation state, and dispersion state of the fine particles inside the coating film. It is. The fine particles having voids may be either inorganic or organic, and include, for example, those made of metal, metal oxide, and resin, and preferably silicon oxide (silica) fine particles.

Furthermore, a material in which a sol obtained by dispersing ultrafine silica particles of 5 to 30 nm in water or an organic solvent and a fluorine-based film forming agent can be used. The sol in which the ultrafine silica particles of 5 to 30 nm are dispersed in water or an organic solvent is obtained by a method of dealkalizing alkali metal ions in alkali silicate salt by ion exchange or the like, or neutralizing alkali silicate salt with mineral acid. A known silica sol obtained by condensing active silicic acid known by the method, etc., a known silica sol obtained by condensing alkoxysilane with hydrolysis in an organic solvent in the presence of a basic catalyst, and the above-mentioned An organic solvent-based silica sol (organosilica sol) obtained by substituting water in the aqueous silica sol with an organic solvent by a distillation method or the like is used. These silica sols can be used in both aqueous and organic solvent systems. In producing the organic solvent-based silica sol, it is not necessary to completely replace water with the organic solvent. The silica sol contains solids 0.5 to 50 wt% concentration as SiO _2. Various structures such as a spherical shape, a needle shape, and a plate shape can be used for the structure of the ultrafine silica particles in the silica sol. As the film forming agent, alkoxysilane, metal alkoxide, hydrolyzate of metal salt, or fluorine-modified polysiloxane can be used. According to a preferred embodiment of the low refractive index layer, “fine particles having voids” are preferably used.

  The low-refractive index layer is prepared by diluting the above-described material into a solvent, for example, by spin coating, roll coating, printing or the like on a predetermined layer such as a high-refractive index layer or a flattening layer and drying it. Thereafter, it can be obtained by curing with heat or radiation (in the case of ultraviolet rays, the above-mentioned photopolymerization initiator is used). Alternatively, the low refractive index layer can be provided by a vapor phase method (or dry coating method) such as vacuum deposition, sputtering, plasma CVD, or ion plating.

The high refractive index layer is formed by using a binder resin having a high refractive index in order to increase the refractive index, adding ultrafine particles having a high refractive index to the binder resin, or using these in combination. To do. The refractive index of the high refractive index layer is preferably in the range of 1.55 to 2.70.
As the resin used for the high refractive index layer, any resin can be used as long as it is transparent, and thermosetting resins, thermoplastic resins, ionizing radiation (including ultraviolet rays) curable resins, and the like can be used. . Thermosetting resins include phenolic resin, melamine resin, polyurethane resin, urea resin, diallyl phthalate resin, guanamine resin, unsaturated polyester resin, amino alkyd resin, melamine-urea cocondensation resin, silicon resin, polysiloxane resin, etc. A curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier and the like can be added to these resins as necessary.
As ultrafine particles having a high refractive index, for example, ZnO (refractive index n = 1.9), TiO ₂ (refractive index n = 2.3 to 2.7), which can also have an ultraviolet shielding effect, fine particles of CeO ₂ (refractive index n = 1.95) also may be antistatic effect to prevent adhesion of dust are granted, SnO ₂ (refractive index n = 1.95) doped with antimony or Fine particles of ITO (refractive index n = 1.95), Cs _0.33 WO ₃ (fine particles of cesium-containing tungsten oxide (refractive index n = 2.5 to 2.6), which can also obtain a near infrared shielding effect, In addition, fine particles of gold goethite (diamond, C; refractive index n = 2.37 to 2.47), which can also provide an effect of wear resistance, can be given as other fine particles such as Al ₂ O ₃ (refractive index). _{n = 1.63), La 2 O} 3 ( refractive index n 1.95), ZrO ₂ (refractive index _{n = 2.05), Y 2 O} 3 ( refractive index n = 1.87), and the like. These fine particles are used alone or as a mixture, the organic A colloidal dispersion dispersed in a solvent or water is favorable in terms of dispersibility, and the particle size is preferably 1 to 100 nm, and preferably 5 to 20 nm from the transparency of the coating film.

In order to provide a high refractive index layer, the material described above is diluted with a solvent, for example, provided on a substrate by wet coating such as spin coating, roll coating, printing, etc. The photopolymerization initiator may be used for curing. Alternatively, the high refractive index layer can be provided by a vapor phase method (or dry coating method) such as vacuum deposition, sputtering, plasma CVD, or ion plating.
The thickness of the low refractive index layer is not particularly limited. Usually, the product of the refractive index and the thickness of the low refractive index layer is about ¼ of the wavelength of visible light (380 nm to 780 nm) at which the reflectance should be minimized. (95 to 195 nm).

(Abrasion resistant functional layer)
The scratch-resistant (hard coat) layer preferably exhibits a hardness of “H” or higher in a pencil hardness test specified by JISK5600-5-4 (1999). The material is not particularly limited as long as the same transparency as the substrate can be realized.
The scratch-resistant (hard coat) layer is usually formed as a cured resin layer. As the position and form to be formed, either one of the constituent layers of the optical specular antireflection layer is used, or it is formed as an independent separate layer between the optical specular antireflection layer and the flattening layer.
As the curable resin to be used, an ionizing radiation curable resin, other known curable resins, or the like may be appropriately employed according to required performance. Examples of the ionizing radiation curable resin include acrylate-based, oxetane-based, and silicone-based resins. For example, acrylate-based ionizing radiation curable resins are, for example, polyfunctional (meth) acrylate prepolymers such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, or trimethylolpropane tri (meth) ) Trifunctional or higher polyfunctional (meth) acrylate monomers such as acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc., alone or in combination of two or more selected from these It can be formed as a coating film using an ionizing radiation curable resin.
The scratch resistance function (hard coat) can be formed by a wet film formation method such as coating on the flattening layer or the optical specular antireflection layer by diluting the material with a solvent as necessary.
The thickness of the scratch-resistant functional layer is not particularly limited, but is preferably 1.0 μm or more and 20 μm or less, more preferably 3.0 μm or more and 5 μm or less.

[Method of forming optical mirror antireflection layer]
As a method of forming the optical specular antireflection layer 6 on the flattening layer, a method of transferring the optical specular antireflection layer from the transfer sheet (a flattening layer is formed on the optical specular antireflection layer on the transfer sheet). Both layers may be simultaneously transferred onto the conductive pattern layer), a method of laminating and laminating an optical specular antireflection layer previously formed on a support made of a transparent resin sheet (lamination method), or flattening Any of the methods of coating the optical specular antireflection layer directly on the layer may be used.
Hereinafter, the transfer method and the laminating method will be described.

(Transfer method)
In the present invention, a transfer method using a transfer sheet in which an optical specular antireflection layer or an optical specular antireflection layer and a flattening layer are detachably laminated on a peelable substrate is formed as an optical specular antireflection layer. This is one of the preferable methods.
In order to transfer the optical specular antireflection layer onto the flattening layer previously formed on the conductive pattern layer, first, the optical specular antireflection layer forming side of the transfer sheet is brought into contact with the flattening layer surface and applied. The transfer sheet and the planarizing layer are laminated by pressing. Depending on the pressure alone or the material of the adhesive layer or planarizing layer, an adhesive layer is interposed between the optical anti-reflection layer and the planarizing layer by heating, ionizing radiation irradiation, etc., as appropriate. Adhering with or without intervening. Thereafter, only the peelable substrate is peeled and removed, and the optical specular reflection preventing layer is left on and adhered to the planarizing layer.
Moreover, you may obtain the transfer sheet which laminated | stacked the optical specular reflection prevention layer and the planarization layer on the peelable base material, and may transfer this to a metal pattern layer by various transfer methods. After the transfer, the peelable substrate is peeled off together with the release layer, and a filter with an optical specular antireflection layer in which a flattening layer is embedded in the unevenness of the metal pattern layer can be obtained.

(Peelable substrate)
It consists of an appropriate base material sheet. If necessary, it is preferable to form a release layer on the transfer layer side in order to ensure releasability (also referred to as releasability) from the transfer layer.
As the substrate sheet, a sheet having high strength and dimensional stability (elastic modulus) with respect to stress, heat resistance (especially when overheating during transfer), and high surface smoothness is selected. A resin sheet having a thickness of about 20 to 100 μm or a paper having a basis weight of 20 to 100 g / m ² is used. Examples of the resin include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and polyolefin resins such as polypropylene and polymethylpentene. As the paper, high quality paper, parchment paper, glassine paper, sulfuric acid paper or the like that is as uniform as possible is used.
The release layer is formed when the base sheet itself has insufficient peelability from the optical specular reflection preventing layer (transfer layer). For the release layer, a material having high adhesion to the base sheet and high releasability from the transfer layer is selected.
As a material for the release layer, melamine resin, silicon resin, polyolefin resin, or the like is used. If necessary, a release agent made of wax, fluororesin or the like is added thereto. The thickness of the release layer is usually about 0.1 to 5 μm.

(Transfer layer)
It is a layer transferred from the peelable substrate side to the planarizing layer side. It consists of at least the optical specular antireflection layer. In addition, an adhesive layer and other transfer layers are included as necessary.
The adhesive layer as one element of the transfer layer is made of a material having adhesion to both the optical specular antireflection layer and the planarizing layer.
As the material of the adhesive layer, for example, an acrylic resin, a vinyl chloride-vinyl acetate copolymer, a thermoplastic polyester resin, or the like selected from the same materials as those exemplified in the planarization layer as the thermoplastic resin may be used. Can be used. In addition, thermosetting resins or ionizing radiation curable resins can also be used.
The thickness of the adhesive layer is usually about 1 to 30 μm.
There are three forms of forming the adhesive layer.
(1) Instead of forming a transfer layer, an adhesive layer is separately applied on a planarizing layer that has been formed in advance on a conductive pattern. Then, on the adhesive layer on the planarizing layer, the optical specular reflection preventing layer is formed by any one of direct coating, transfer, or lamination of lamination sheets.
Further, when the optical specular antireflection layer itself has a sufficient adhesive force to the planarizing layer, the adhesive layer can be omitted.
(2) An adhesive layer is previously formed as a transfer layer on the transfer sheet. On the other hand, a planarization layer is formed in advance on the conductive pattern layer. In this state, the adhesive layer is transferred from the transfer sheet onto the planarizing layer. If both the adhesive layer and the optical specular reflection preventing layer are formed as a transfer layer on the transfer sheet, the adhesive layer and the optical specular reflection preventing layer are simultaneously formed in one transfer step. Can do. In this case as well, the adhesive layer can be omitted if the optical specular antireflection layer itself has a sufficient adhesive force to the planarizing layer.
(3) An adhesive layer (flattening layer and adhesive layer combined layer) that can also function as a flattening layer as a transfer layer is previously formed on the transfer sheet. On the other hand, no planarization layer is formed on the conductive pattern layer. In this state, the adhesive layer is transferred from the transfer sheet onto the conductive pattern layer. At the time of bonding, the adhesive layer is given fluidity by heating or the like, and the adhesive layer is filled in the unevenness of the conductive pattern layer, and the surface of the adhesive layer is flattened, and then the adhesive layer Solidify. Thus, the formation of the planarizing layer is completed simultaneously with the formation of the adhesive layer on the conductive pattern layer. Even in this form, if both the adhesive layer and the flattening layer combined layer and the optical specular antireflection layer are formed as a transfer layer on the transfer sheet, the flattening layer is formed in one transfer step. The formation of the adhesive layer and the formation of the optical specular reflection preventing layer can be performed simultaneously.
The other transfer layer provided as necessary is, for example, a layer containing a near-infrared absorbing agent, an ultraviolet absorbing agent, a neon light absorbing agent, various coloring dyes, an antistatic agent, etc. in a resin as appropriate. Functions as an infrared absorbing layer.

  The flattening layer can be provided on the optical mirror antireflection layer and other transfer layer (provided if necessary) to be the outermost layer of the transfer layer. By applying a thermal transfer method to such a transfer sheet, the transfer layer is transferred onto the metal pattern layer, and a filter with an optical specular antireflection layer in which a flattening layer is embedded in the unevenness of the metal pattern layer is obtained.

  Such a transfer sheet can be in the form of a single sheet cut into a desired size or shape, or in the form of a continuous belt wound up on a roll (roll).

(Lamination method)
As a method for forming the optical mirror surface antireflection layer 6 in the present invention, a laminating method is a preferable method in addition to the above-described transfer method.
In the laminating method, an optical mirror antireflection layer is formed on one surface of the transparent base sheet 10, and an adhesive layer 11 of a thermoplastic resin having a thickness capable of forming a planarizing layer by filling the unevenness of the metal pattern layer on the other surface. An optical specular antireflection sheet 12 formed into a film is prepared, and the adhesive layer side of the thermoplastic resin is superimposed on the electromagnetic wave shielding filter in a direction facing the metal pattern layer, Is heated to above the melting point or melting temperature of the thermoplastic resin to cause the adhesive layer to become a liquid, and then cooled to below the melting point to the melting temperature to solidify (also referred to as solidification), thereby preventing optical specular reflection. The sheet is pasted (laminated or laminated) on the mesh pattern electromagnetic wave shielding filter.
The transparent base sheet 10 may be appropriately selected from known materials and thicknesses in consideration of required physical properties such as light transmittance in the visible region, heat resistance, and mechanical strength, and is a resin sheet having a thickness of 20 to 200 μm. Is preferred. Examples of the resin include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, and polyolefin resins such as polypropylene and polymethylpentene.
As described above, the optical specular antireflection layer is appropriately composed of an antiglare layer (AG layer) or an antireflection layer (AR layer), and a hard coat layer (HC layer).
The thermoplastic resin adhesive is solid at room temperature (0 to 30 ° C. or around), and is melted at around 100 ° C., and then cooled to a melting point or below the melting temperature to be solidified. A material having adhesion to both the layer and the substrate sheet. The thermoplastic resin adhesive used in such a form is also called a hot melt adhesive, a heat-sensitive adhesive, a heat seal adhesive, or the like. To do. Examples of such a thermoplastic resin adhesive material include, as a thermoplastic resin, various acrylic resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymer listed in the material of the planarizing layer. A coalescence, a thermoplastic polyester resin, etc. can be used conveniently. The adhesive layer of the thermoplastic resin fills the unevenness of the metal pattern layer and becomes a flattening layer, and the thickness thereof needs to be equal to or greater than the thickness of the metal pattern layer.

When manufacturing a filter having electromagnetic wave shielding properties and optical specular antireflection properties suitable for disposing on the front surface of the display by the laminating method, the following method is used.
An optical specular antireflection sheet formed by forming an optical specular antireflection layer on one side of the base sheet and an adhesive layer of a thermoplastic resin on the other side, and the adhesive layer side of the thermoplastic resin being a metal Overlaying on the electromagnetic wave shielding filter in the direction facing the pattern layer, a heat roller is applied from above the optical specular reflection preventing layer and moved in one direction, and heat pressure is applied intermittently. The portion to which the heat pressure is applied is a portion where an optical specular reflection preventing sheet is adhered to an electromagnetic wave shielding filter and an optical specular reflection preventing layer is provided. When used as a front filter of an image display device, it corresponds to a region facing the screen. The part where the heat pressure is not applied is outside the area facing the screen when it is used as the front filter of the image display device and hits the grounding area, but here the optical specular antireflection sheet is not adhered to the electromagnetic wave shielding filter. (As shown in FIG. 2, the optical mirror surface antireflection sheet 12 and the thermoplastic resin adhesive layer 11 are in a state of floating from the aluminum pattern 2), and the metal pattern layer is exposed without providing the optical mirror surface antireflection layer. is there. Only heating may be used, but usually both heating and pressurization are applied. For heating and pressurization (application of hot pressure), the periphery of a cylindrical core material such as iron is usually pressed by a heating roller whose surface is covered with a heat-resistant elastic body such as silicon rubber. As the hot pressure condition by such a heating roller, a temperature of 100 to 220 ° C., a pressure of 0.1 to 50 kgf / cm ² , and a time of 1 to 60 seconds are preferable. Heated or heated and pressurized, the molten adhesive sufficiently fills the unevenness of the aluminum pattern, sufficiently replaces the air in the recess, and the surface opposite to the aluminum pattern (upper surface side) of the adhesive layer is After sufficiently flattening, the thermoplastic resin adhesive layer 11 is cooled to its melting temperature or below its melting point, and finally to room temperature, to solidify the thermoplastic resin adhesive layer 11. For such cooling, it is sufficient to leave it alone in room temperature air. However, in the case of cooling more efficiently, means such as spraying cold air, contact with a cooling roller, and immersion in cold water are adopted.
Next, the laminate obtained by intermittently laminating the optical specular reflection preventing sheet on the electromagnetic shielding filter thus obtained is applied to the electromagnetic shielding filter of the adhesive layer of the optical specular reflection preventing sheet as shown in FIG. In view of the boundary between the bonded portion and the non-bonded portion and the workability, more preferably, the half-cut blade 13 from the optical mirror antireflection layer side at a position about 1 to 10 mm away from the boundary portion to the non-bonded portion side (outside) And half cut. The half-cut blade cuts the optical specular antireflection layer and the transparent base sheet, and bites into the surface layer of the adhesive layer 11 only slightly.
Next, for the laminate after the half cut in which the optical mirror surface antireflection sheet is cut, when the adhesive layer not applied with heat pressure peels off the non-adhesive optical mirror surface antireflection sheet portion to the electromagnetic wave shielding filter, the aluminum pattern The metal pattern layer is exposed on the grounding region on the periphery of the layer 2. Then, in the middle of the exposed portion of the metal pattern layer, the entire length from the optical mirror surface antireflection layer 6 shown in FIG. The laminate sheet is cut into sheets.
Of the peripheral portion of the optical filter for one screen that has been completed, the entire cut portion (the entire periphery of the peripheral portion or a part thereof) has a predetermined width in the long side direction and the short side direction, and the metal pattern layer is exposed. Yes.
In the case of the transfer method, a half-cut process is not necessary when manufacturing a single-wafer filter. Since the optical mirror surface antireflection layer and the adhesive layer / flattening layer are formed on the release film, the optical mirror surface antireflection layer portion and the adhesive are adhered to the electromagnetic wave shielding filter on the peripheral edge when the release film is peeled off. The agent layer portion can be peeled off to expose the metal pattern layer. On the other hand, in the laminating method that does not have such a configuration, it is necessary to half-cut the optical specular antireflection sheet at the boundary between the adhesive layer of the adhesive layer of the optical specular antireflection sheet and the non-adhesive part.
Further, as an embodiment of the optical filter of the present invention, for the various laminated structures described above, 1 selected from optical filter layers other than the optical specular antireflection layer or various functional layers other than the optical filter. The form which added the layer more than the layer in the suitable position between layers is mentioned.
Examples of optical filter layers other than the optical specular antireflection layer include a near infrared absorption filter layer, an ultraviolet absorption filter layer, a neon light absorption filter layer that absorbs neon light emission of the PDP, and a color correction that corrects a display image to a desired color tone. Specific light transmission (coloring) filter layers such as functions, and the fine louver type filter layers described in JP-A-2007-272161 and the like can be mentioned.
As various functional layers other than such an optical filter, in addition to the anti-scratch function (hard coat) layer exemplified above as a part of the constituent layers of the antireflection layer, an impact resistant layer (impact absorbing layer), an antistatic layer, a contamination Examples include a prevention layer, an antibacterial layer, an antibacterial layer, and a flameproof or flame retardant layer.
Of these, the embodiment in which the above-mentioned minute louver type filter layer is laminated will be described in detail as an example.
The fine louver type filter layer has a wedge-shaped black portion made of a black resin and extending in one direction in a transparent resin layer (thickness of about 20 to 5000 μm) and having a rectangular or triangular column shape. It has a configuration in which a large number are embedded and arranged at predetermined intervals with their existing directions being parallel to each other. A light-transmitting portion (opening) made of a transparent resin is formed between the adjacent wedge-shaped black portions, and optically has a structure in which a ridge, a lattice, or an armor door is miniaturized. The cross section (main cut surface) of the black portion on the wedge orthogonal to the extending direction is a quadrangle, and preferably a trapezoidal shape. The arrangement period of the black part on the wedge (in the direction orthogonal to the main cut surface) is usually about 10 to 1000 μm, and the height of the main cut surface (the length measured in the normal direction of the layer) is the layer. About 10 to 100% of thickness, width of main cut surface (length measured in the direction perpendicular to the normal, evaluation is based on average length of upper and lower bases for trapezoids, and base for triangles The evaluation is about 10 to 1000 μm and the base angle is about 70 to 120 degrees. In addition, the width of the translucent portion between the wedge-shaped black portions (the length measured in a direction perpendicular to the normal of the layer, and the average of the upper and lower bases when the main cut surface of the translucent portion is trapezoidal) (Evaluated by length) is about 10 to 1000 μm.
When the main cut surface of the translucent part is trapezoidal, the change (increase / decrease) in the thickness direction of the cross-sectional area (opening area) in the direction parallel to the sheet surface of the translucent part is (1) Observation of the image display device A form in which the opening area increases toward the viewer, (2) a form in which the opening area does not change toward the viewer of the image display device, and (3) a mode in which the opening area decreases toward the viewer of the image display device, There are three forms. What is necessary is just to design according to a use, the objective, and required performance (viewing angle, image contrast at the time of external light incidence, etc.).
Usually, a transparent resin sheet is further laminated on one or both sides of the front and back of the transparent resin layer for reasons such as reinforcing the strength of the transparent resin layer in which the black portion on the wedge is arranged and ease of production. It is preferable to do.

  The optical filter of the present invention can be used for various applications. In particular, plasma displays (PDP), cathode ray tube displays (CRT), liquid crystal displays (LCDs) used in display units of television receivers, various measuring instruments and instruments, various office equipment, various medical equipment, computer equipment, telephones, etc. ), Suitable for a front filter of an image display device such as an electroluminescent display (EL), and particularly suitable for a plasma display. In addition, electromagnetic shielding such as windows of various home appliances such as windows of buildings such as houses, schools, hospitals, offices, stores, vehicles, vehicles, airplanes, ships, microwave ovens, etc. It can also be used for antireflection applications.

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

[Example 1]
(Aluminum mesh production)
First, a continuous strip-shaped rolled aluminum foil having a thickness of 12 μm was prepared as a metal foil for an aluminum pattern. When the thickness of the oxide film on the surface of this aluminum foil was measured, it was 8 mm on both the upper and lower surfaces.
Further, as a transparent substrate, a continuous belt-like uncolored transparent biaxially stretched polyethylene terephthalate film having a polyester resin primer layer formed on one side was prepared.
Next, the primer layer surface of the transparent substrate and the glossy surface of the aluminum foil are cured with respect to 12 parts by mass of a transparent two-component curable urethane resin-based adhesive (polyester polyurethane polyol having an average molecular weight of 30,000 as a main component). (Including 1 part by mass of xylylene diisocyanate-based prepolymer as an agent) and then cured at 50 ° C. for 3 days to form a continuous strip of aluminum having a 7 μm thick transparent adhesive layer between the aluminum foil and the transparent substrate. A foil laminated sheet was obtained.
Next, the aluminum foil of the aluminum foil laminated sheet is subjected to a chemical etching process using a photolithography method, and a frame-like area is formed in the mesh-like area including the opening and the line part, and the outer edge surrounding the mesh-like area. An aluminum pattern having a grounding region with no opening was formed.
Specifically, the etching was consistently performed from masking to etching on the continuous belt-like laminated sheet using a production line for a color TV shadow mask. That is, after applying a photosensitive etching resist on the entire surface of the aluminum foil of the laminated sheet, a desired mesh pattern is closely exposed, developed, hardened, and baked to form a resist on the area corresponding to the mesh opening. After forming the resist pattern in which the layer is not formed, the aluminum foil in the resist layer non-formed part is removed by etching with an acid aqueous etchant containing ferric chloride to have a mesh-like opening. An aluminum pattern was formed, and then washing with water, stripping of the resist, washing, and drying were sequentially performed.
The mesh shape of the mesh area (image display area) is such that the line width of the linear line portion whose opening is a square and non-opening is 20 μm, the line interval (pitch) is 300 μm, and the height of the line portion. When cut into a rectangular sheet of 12 μm, the bias angle defined as the minor angle formed by the line portion and the long side of the rectangle was 49 degrees. Thus, the intermediate body of the electromagnetic wave shielding filter of width dimension 605mm was obtained, and it wound up in roll shape.
The obtained roll-shaped electromagnetic shielding filter intermediate is continuously supplied to the blackening device using rolls, tows, and rolls, and a nickel compound blackening layer is formed on the aluminum pattern surface of the intermediate. And wound up to obtain an electromagnetic wave shielding filter.
As for the pattern accuracy of the obtained aluminum pattern, the variation in the line width of the mesh is 4.5 μm, the surface unevenness has no problem in appearance, and there is also a variation in the surface electrical resistance value at a level that hinders electromagnetic shielding properties. There wasn't. Moreover, when observed visually, the cloudiness resulting from the bubble in a mesh pattern opening part was not recognized.

(Production of AR transfer sheet)
Release substrate preparation:
A long biaxially stretched polyethylene terephthalate (PET) film having a width of 1000 mm and a thickness of 100 μm having a melamine resin release layer formed on one side was prepared.
Formation of antireflection layer:
As a composition for forming a low refractive index layer constituting an antireflection layer, 1.95 parts by mass of pentaerythritol triacrylate (PETA), 1-hydroxy-cyclohexyl-phenyl-ketone [Ciba Specialty as a photopolymerization initiator, 0.1 parts by mass of trade name “Irgacure 184” manufactured by Chemicals Co., Ltd. was added, and then a treated silica sol-containing solution [fine particles having voids (average particle size 60 nm), solid content of silica sol 20% by mass, solvent: methyl isobutyl ketone] 12.3 parts by mass, and silica particle-containing solution [manufactured by Nacalai Tesque, trade name “sicical”, giant particles (average particle size 100 nm), silica particle solid content 20% by mass, solvent: methyl isobutyl ketone] 1.23 mass After mixing the parts, add 83.5 parts by mass of methyl isobutyl ketone and UV cure A coating solution for forming a low refractive index layer in the form of a conductive resin composition was prepared.
The low refractive index layer-forming coating solution was applied to the release layer of the PET film at a dry weight of 0.1 g / m ² (bar coating), and then dried at 40 ° C. for 60 seconds. Thereafter, using a UV irradiation device made of high-pressure mercury vapor, the film was cured by UV irradiation at an irradiation dose of 200 mJ / cm ² to form a low refractive index layer, and an antireflection layer was continuously formed.
The film thickness after curing of the low refractive index layer was 90 nm and the refractive index was 1.44.
Next, 100 parts by mass of a composition obtained by mixing a urethane acrylate prepolymer and 1,6 hexanediol diacrylate, 5 parts by mass of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator, and 300 parts by mass of methyl cellosolve were mixed and homogenized. A coating agent comprising a radiation curable resin is applied onto the antireflection layer (low refractive index layer) by a roll coater method, dried at 80 ° C., and then irradiated with a 80 W high pressure mercury lamp to form a hard coating layer having a thickness of 3 μm. Formed.
On the hard coat layer, a solution comprising 10 parts by mass of a thermoplastic polyester resin, 40 parts by mass of toluene, and 50 parts by mass of methyl ethyl ketone was continuously applied at a rate of 50 m / min by a reverse roll coating method and dried to a thickness of 15 μm. An adhesive layer (also used as a flattening layer) was formed to obtain an antireflection transfer sheet.

(Production of AR layer on mesh)
The antireflection transfer sheet thus obtained was transferred onto the mesh by the thermal transfer method, and the adhesive layer side of the transfer sheet was brought into contact with the mesh side of the electromagnetic wave shielding film, and the surface was brought to 140 ° C. Pressurization was performed with a heated silicon rubber roll (with iron core), and heating was performed simultaneously. The melted adhesive layer is filled into the mesh recesses and then cooled in a room temperature (23 ° C.) atmosphere to solidify the adhesive layer, and the surface of the PET film is formed on the surface of the adhesive layer. The flat surface was shaped, and the surface of the adhesive layer that had been cooled and solidified (hard coat layer interface) was flattened. That is, in this case, the adhesive layer functions as a planarizing layer. Thereafter, the polyethylene terephthalate film was peeled off together with the release layer, and an optical filter of Example 1 comprising a mesh with an antireflection layer was produced.

[Example 2]
In Example 1, except that the following points were changed for the mesh pattern-shaped electromagnetic wave shielding layer (particularly, the formation of the planarizing layer on the metal pattern layer) and the AR transfer sheet (particularly, the thickness of the adhesive layer). The optical filter of Example 2 was produced in the same manner as Example 1.
Similar to Example 1, an excellent surface free from surface unevenness, variation in electric resistance value, and white turbidity due to mixing of bubbles was obtained.
(Formation of mesh pattern electromagnetic shielding layer)
On the metal pattern layer of the electromagnetic wave shielding film produced in the same manner as in Example 1, a solution comprising 10 parts by mass of a thermoplastic polyester resin, 40 parts by mass of toluene, and 50 parts by mass of methyl ethyl ketone was applied with a bar coater and dried. A flattened layer having a dry thickness (measured from the surface of the transparent substrate 1 and having a film thickness at the opening) of 15 μm was formed.
(Production of AR transfer sheet)
The hard coat layer was formed in the same manner as the AR transfer sheet of Example 1. Next, a solution comprising 10 parts by weight of a thermoplastic polyester resin, 40 parts by weight of toluene and 50 parts by weight of methyl ethyl ketone is continuously applied to the hard coat layer at a rate of 50 m / min by a reverse roll coating method, and dried. A 1 μm adhesive layer was formed to obtain an antireflection transfer sheet.

[Example 3]
(Preparation of optical mirror antireflection sheet)
A long biaxially stretched polyethylene terephthalate (PET) film having a width of 500 mm and a thickness of 100 μm was prepared.
A coating agent made of the same ionizing radiation curable resin as used in Example 1 was applied onto the PET film, dried, and then irradiated with a high-pressure mercury lamp to form a 6 μm thick hard coat layer.
Furthermore, a low refractive index layer-forming coating solution constituting the same antireflection layer as used in Example 1 was applied thereon, dried, and then irradiated with a high-pressure mercury lamp to give a low refractive index having a thickness of 150 μm. A layer was formed.
On a PET film opposite to the surface on which the hard coat layer and the low refractive index layer are formed, a vinyl chloride / vinyl acetate heat melting adhesive (DIC, heat sealant A-100Z) is added to toluene and methyl ethyl ketone. The diluted solution was applied to a mixed solvent having a mass ratio of 1: 1 to 1 and the diluted solvent was dried to form an adhesive layer having a thickness of 30 μm.
Thus, an optical specular antireflection sheet having an AR layer on one side and a melt-type adhesive layer on the back side was obtained.
(Attachment of optical specular reflection prevention sheet and electromagnetic wave shielding filter)
The mesh-like aluminum pattern side of the mesh pattern-like electromagnetic shielding film having a width of 605 mm obtained in the same manner as in Example 1 and the adhesive layer side of the optical mirror surface antireflection sheet having a width of 500 mm obtained above are opposed to each other. Combined.
By pressing a heat roller with a heating width of 510 mm that covers the iron core surface from the AR layer of the specular antireflection sheet, the adhesive of the thermoplastic resin melts to form a mesh. Into the aluminum pattern recess and fills the mesh recess without leaving bubbles. Then, it cooled in room temperature (23 degreeC) atmosphere, this adhesive layer was solidified, and the optical filter which laminated the optical specular reflection prevention sheet on the mesh pattern-form electromagnetic wave shielding filter was obtained.
Here, hot pressing conditions of heat roller temperature 110 ° C., a pressure 30 kgf / cm ^2, the time 20 seconds. The heat roller was moved in the flow direction to apply heat pressure intermittently. The portion to which the heat pressure is applied is the central portion of the aluminum pattern 2 where the AR layer is provided by adhering the optical mirror surface antireflection sheet to the electromagnetic wave shielding filter, the distance in the flow direction is 1100 mm, and the portion to which the heat pressure is not applied is the optical mirror surface The part where the antireflection sheet was not adhered to the electromagnetic wave shielding filter and the metal pattern layer was exposed without providing the AR layer was a distance of 200 mm in the flow direction.
(Half cut of a light mirror antireflection sheet)
Next, a laminated body obtained by intermittently laminating an optical specular reflection preventing sheet on the mesh pattern electromagnetic shielding filter obtained in this way is bonded to the electromagnetic shielding filter of the adhesive layer of the optical specular reflection preventing sheet. A half-cut blade (Flexible Pinnacle Die made by Tsukaya Cutlery; blade size 595 mm × 1105 mm) was inserted from the AR layer side 42.5 mm outside the boundary of the non-adhered portion and half-cut. Here, the clearance between the lowered half-cut blade and the backing plate is 125 μm, and the half-cut blade cuts the AR layer and the PET film and bites into the surface layer of the adhesive layer only slightly.
Next, with respect to the laminate after the half cut obtained by cutting the optical mirror surface antireflection sheet, a non-adhesive optical mirror surface antireflection sheet is applied to the electromagnetic wave shielding filter to which heat pressure is not applied, and the outer portion from the half cut line is disposed. When peeled off, the aluminum pattern layer (metal pattern layer) in the peripheral region on the mesh is exposed. And the long laminated body sheet | seat was cut | judged and cut into pieces by cutting all in the middle of the exposed part pinched by the metal pattern layer adjacent to a flow direction.
In the completed optical filter for one screen, the metal pattern layer is exposed with a width of 95 mm in the long side direction, and the metal pattern layer is exposed with a width of 47 mm in the short side direction. In addition, destruction, disconnection, etc. were not looked at by the metal pattern layer of the location where the half cut blade of the long side direction both ends entered.

[Comparative Example 1]
A mesh with an antireflection layer was produced in the same manner as in Example 1 except that an aluminum foil having a surface oxide film thickness of 15 mm was used.
The pattern accuracy of the obtained aluminum pattern is that the mesh line is frequently disconnected (line width variation of 20 μm or more), the surface appearance is noticeable in appearance, the surface resistance value varies greatly, and the electromagnetic wave shielding property is Compared with the case of Example 1, it decreased.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Aluminum pattern 3 Aluminum oxide film 4 Transparent adhesive layer 5 Flattening layer 6 Optical mirror surface antireflection layer 10 Transparent base material sheet 11 Adhesive layer of thermoplastic resin 12 Optical mirror surface antireflection sheet 13 Half cut blade

Claims (3)

On the transparent substrate, a metal pattern layer, a flattening layer made of a transparent resin, filling the unevenness of the metal pattern layer and having a flat surface, and an optical mirror antireflection layer are laminated in this order,
The metal pattern layer is an aluminum pattern layer, and the thickness of the aluminum oxide film on at least the upper surface of the aluminum pattern layer (the surface of the aluminum pattern layer far from the transparent substrate) is 0 to 13 mm. A filter having electromagnetic shielding properties and optical specular reflection prevention properties. A method for producing a filter having an electromagnetic wave shielding property and a light mirror surface antireflection property, wherein a metal pattern layer and a light mirror surface antireflection layer are formed on one surface of a transparent substrate,
A metal pattern layer forming step of forming an aluminum pattern layer having an aluminum oxide film thickness of 0 to 13 mm on at least the upper surface on the transparent substrate;
After the metal pattern layer forming step, a transfer sheet is prepared by releasably laminating an optical specular antireflection layer on a peelable substrate, and the metal pattern layer is filled with irregularities so that the surface is flat. The transfer sheet is overlapped with the optical mirror surface antireflection layer side facing the metal pattern layer side with the forming layer interposed therebetween, so that the optical mirror surface antireflection layer is formed on the metal pattern layer and the planarizing layer. 2. The production of a filter having electromagnetic wave shielding properties and optical mirror surface antireflection properties according to claim 1, comprising: an optical mirror surface antireflection layer transfer step of laminating layers and peeling and removing the peelable substrate. Method. A method for producing a filter having an electromagnetic wave shielding property and a light mirror surface antireflection property, wherein a metal pattern layer and a light mirror surface antireflection layer are formed on one surface of a transparent substrate,
A metal pattern layer forming step of forming an aluminum pattern layer having an aluminum oxide film thickness of 0 to 13 mm on at least the upper surface on the transparent substrate;
After the metal pattern layer forming step, an optical mirror antireflection layer is formed on one surface of the substrate, and an adhesive layer of a thermoplastic resin having a thickness capable of forming a planarizing layer by filling the unevenness of the metal pattern layer on the other surface. The optical specular antireflection sheet formed into a film is overlaid on the metal pattern layer with the thermoplastic resin adhesive layer facing the metal pattern layer, and this is over the melting point or the melting temperature of the thermoplastic resin. The electromagnetic wave shielding property and optical specular reflection according to claim 1, further comprising: an optical specular antireflection sheet laminating step of heating to make the adhesive layer into a liquid, and then cooling to solidify. A method for manufacturing a filter having preventive properties.

Images