BEST MODE FOR CARRYING OUT THE INVENTION

[0099] A display filter, a display apparatus and a method for production of the same according to the present invention are now described in detail with reference to the preferred embodiments shown in the accompanying drawings.

[0100] The display filter according to the invention functions as a light control film having filter characteristics which correct a visible light spectrum of a display screen by containing a dye having an absorption maximum in a wavelength range of from 570 to 605 nm.

[0101] Further, the display filter according to the invention functions as an electromagnetic wave shielding body having filter characteristics which shield an electromagnetic wave from a display screen by comprising a transparent electrically conductive layer having a surface resistance of from 0.01 to 30 Ω/square.

[0102] Further, the display filter according to the invention functions as a near-infrared ray filter having filter characteristics which shield a near-infrared ray from the display screen by containing a near-infrared absorbing dye having an absorption maximum in a wavelength range of from 800 to 1100 nm.

[0103] The display filter having such functions is bonded directly on a surface of the display such as a plasma display whereby improvements such as cost reduction, a weight reduction/a thickness reduction, an enhancements of a panel protection property, workability at the time of a problem occurrence, and productivity can be aimed for.

[0104] The electromagnetic wave shielding body according to the present invention comprises at least a transparent electrically conductive layer (D), having at least a surface resistance of from 0.01 to 30 Ω/square, which has been formed on one major surface of a polymer film (B) and a transparent adhesive layer (C) formed on the other major surface of the polymer film (B), and further comprises an electrically conducting portion formed on the transparent electrically conductive layer (D), and a functional transparent layer (A) formed thereon directly or via the transparent adhesive layer.

[0105] Further, the electromagnetic wave shielding body according to the invention comprises at least a transparent electrically conductive layer (D), having at least a surface resistance of from 0.01 to 30 Ω/square, which has been formed on one major surface of a polymer film (B) and a functional transparent layer (A) formed on the other major surface of the polymer film (B), and further comprises a electrically conductive adhesive layer and a transparent adhesive layer (C) on the transparent electrically conductive layer (D) Further, the electromagnetic wave shielding body according to the invention comprises at least a polymer film (B), a transparent electrically conductive layer (D), having at least a surface resistance of from 0.01 to 30 Ω/square, which has been formed on one major surface of a polymer film (B), a transparent adhesive layer (C) and a functional transparent layer (A) formed on the other major surface of the polymer film (B).

[0106] Further, the light control film according to the invention comprises at least a polymer film (B), a functional transparent layer (A), having an anti-reflection property and/or an anti-glare property, which has been formed on one major surface of the polymer film (B), a transparent adhesive layer (C) formed on the other major surface of the polymer film (B), and further comprises a dye, and has visible light ray transmittance of from 55 to 90%.

[0107] 1. Polymer Film (B)

[0108] A polymer film (B) functions as a substrate of a filter, for example, the substrate for forming a transparent electrically conductive layer (B) and, since a display filter according to the invention is formed directly on a surface of the display, a transparent polymer film is used.

[0109] The polymer film (B) is not particularly limited so long as it is transparent in a visible wavelength region. Specific examples thereof include polyethylene terephthalate, polyethersulfone, polystyrene, polyethylene naphthalate, polyarylate, polyether ether ketone (PEEK), polycarbonate, polyethylene, polypropylene, a polyamide such as nylon 6, a polyimide, a cellulose type resin such as triacetylcellulose, polyurethane, a fluorine type resin such as polytetrafluoroethylene, a vinyl compound such as polyvinyl chloride, polyacrylic acid, a polyacrylic ester, polyacrylonitrile, an addition polymer of a vinyl compound, polymethacrylic acid, a polymethacrylate, a vinylidene compound such as polyvinylidene chloride, a vinylidene fluoride/trifluoroethylene copolymer, a vinyl compound such as ethylene/vinyl acetate copolymer, and, further, a copolymer of a fluorine type compound, a polyether such as polyethylene oxide, an epoxy resin, polyvinyl alcohol, and polyvinyl butyral; however, the invention is not limited to these examples.

[0110] The polymer film is ordinarily in a thickness of from 10 to 250 μm. When the polymer film is unduly thin, it is difficult to form a filter directly on a surface of the display and flexibility thereof is restricted. Therefore, it is favorable that the thickness of the polymer film (B) is 50 μm or more, and more preferably 75 μm or more. Further, when the thickness thereof is more than 250 μm, flexibility is unduly scarce whereupon there is a case in which it is not suitable to utilize the film wound in roll form. Further, in such an application which requires high transparency as in applications according to the invention, the polymer film having a thickness of about 100 μm has broadly been used.

[0111] The transparent polymer film to be used in the invention has flexibility whereupon a transparent electrically conductive layer can continuously be formed thereon by a roll-to-roll method; hence, along transparent laminate having a large area can efficiently be produced. Further, a filter in film form can easily be formed directly on a surface of the display by means of lamination. Still further, it is favorable that, when a substrate glass of the display is broken, the filter, in which the polymer film is a substrate, bonded directly on the surface of the display can prevent glass pieces from being scattered.

[0112] In the invention, a surface of the polymer film (B) may previously be subjected to a sputtering treatment, a corona discharge treatment, a flame treatment, an etching treatment such as ultraviolet ray irradiation and electron beam irradiation, and prime coating thereby improving adhesiveness of the overlying transparent electrically conductive layer (D) to the polymer film (B). Further, any desired inorganic material layer, for example, made of a metal or the like may be formed between the polymer film (B) and the transparent electrically conductive layer (D). Furthermore, if necessary, a dust prevention treatment such as solvent cleaning and ultrasonic cleaning may be performed, before a transparent electrically conductive film is formed.

[0113] Further, a hard coat film (F) may have been formed on at least one major surface of the polymer film (B) so as to increase scratch resistance of the transparent laminate.

[0114] 2. Hard Coat Layer (F)

[0115] As a hard coat film which comes to be a hard coat layer (F), mentioned is a thermosetting resin, a photo-curable type resin or the like, such as an acrylic type resin, a silicone type resin, a melamine type resin, a urethane type resin, an alkyd type resin, and a fluorocarbon type resin; on this occasion, there is no particular limitation on a type and a forming method thereof. Thickness of the film is from about 1 to about 100 μm. Further, it is permissible that the hard coat layer (F) may contain at least one dye to be described below.

[0116] 3. Transparent Electrically Conductive Layer (D)

[0117] In the electromagnetic wave shielding body according to the invention, a transparent electrically conductive layer (D) is formed on one major surface of a polymer film (B). The term “transparent electrically conductive layer (D)” as used herein is intended to include any transparent electrically conductive film composed of a mono-layered thin film or a multi-layered thin film. Further, the term “transparent laminate (H)” as used herein is intended to include any member in which the transparent electrically conductive layer (D) is formed on a major surface of the polymer film (B).

[0118] As the mono-layered transparent electrically conductive film, mentioned is an electrically conductive mesh such as the metallic mesh, an electrically conductive film having a lattice type pattern or a transparent electrically conductive thin film such as a metallic thin film and an oxide semiconductor thin film.

[0119] As the multi-layered transparent electrically conductive film, mentioned is a multi-layered thin film in which a metallic thin film and a high-refractive-index transparent thin film are laminated to each other. The multi-layered thin film in which the metallic thin film and the high refractive-index transparent thin film are laminated to each other has advantageous characteristics in any one of electric conductivity, near-infrared ray cutting-off capacity and visible light ray transmittance, due to electric conductivity which a metal such as silver has and a near-infrared ray reflection characteristics which a free electron of the metal has and, further, prevention of reflection to be caused by a metal in a specified wavelength region by means of the high-refractive-index transparent thin film.

[0120] In order to obtain a display filter having both electromagnetic wave shielding capacity and near-infrared ray cutting-off capacity, a multi-layered thin film in which a metallic thin film having both high electric conductivity for absorbing the electromagnetic wave and a multiplicity of reflection interfaces for reflecting the electromagnetic wave, and the high-refractive-index transparent thin film are laminated to each other is preferable.

[0121] While, according to the VCCI, Class A, which sets a regulated limit for industrial use, indicates that a radiation field intensity should be less than 50 dBμV/m, whereas Class B, which sets a regulated limit for domestic use, indicates that the radiation-field intensity should be less than 40 dBμV/m. However, in a frequency band extending from 20 MHz to 90 MHz, the radiation field intensity from the plasma display exceeds 40 dBμV/m in the plasma display having a diagonal size of about 20 inches and 50 dBμV/m in the plasma display having a diagonal size of about 40 inches. Thus, these types of plasma displays can not be put to domestic use as they are.

[0122] As a size of a screen and electric power consumption thereof become higher, the radiation field intensity of the plasma display becomes higher whereupon it is necessary to use an electromagnetic wave shielding material having high shielding effectiveness.

[0123] The present inventors have conducted an intensive study and found that; in order to obtain electromagnetic wave shielding capacity necessary for the plasma display as well as high visible light ray transmittance and low visible light ray reflectance, it is necessary that the transparent electrically conductive layer (D) has electric conductivity of a low resistance such that a surface resistance thereof is from 0.01 to 30 Ω/square, more preferably from 0.1 to 15 Ω/square, and still more preferably from 0.1 to 5 Ω/square. The visible light ray transmittance and the visible light ray reflectance, as used herein, indicate values calculated in accordance with JIS (R-3106) on the basis of the wavelength dependence of transmittance and reflectance.

[0124] Further, the present inventors have found that; in order to shield an intense near-infrared ray emitted from the plasma display up to such a level as causes no problem in actual use, it is required to allow a light ray transmittance minimum in a wavelength range of from 800 to 1100 nm of the near-infrared ray in the display filter to be 20% or less and, further, in order to satisfy such a requirement, it is necessary that the transparent electrically conductive layer itself has a near-infrared ray cutting-off property from the reason that a number of constitutional members is required to be decreased and there is a limitation on a near-infrared ray absorption by using a dye. Reflection by the free electron of the metal can be utilized, in order to cut off the near-infrared ray in the transparent electrically conductive layer.

[0125] As the metallic thin film layer becomes thicker, the visible light ray transmittance becomes lower, while as the metallic thin film layer becomes thinner, the reflection of the near-infrared ray becomes weaker. However, by superimposing at least one layer of a laminate constitution in which the metallic thin film layer having a given thickness is interposed between the high-refractive-index transparent thin film layers, it is possible to enhance the visible light ray transmittance and, at the same time, increase a total thickness of the metallic thin film layer. Further, by controlling a number of layers and/or thickness of each layer, it is possible to allow the visible light ray transmittance, the visible light ray reflectance, the near-infrared ray transmittance, a transmitted color and a reflected color to be changed within a given range.

[0126] Ordinarily, as the visible light ray reflectance becomes higher, lighting equipment and the like are more mirrored in the screen whereupon effect to prevent the reflection on the surface of the representation portion is reduced thereby deteriorating visibility and contrast. Further, as the reflected color, an imperceptible color of, for example, white-, blue- or purple-base is preferable. Under these circumstances, as the transparent electrically conductive layer, a multi-layered lamination which is optically designed and controlled in an easy manner comes to be preferable.

[0127] In the electromagnetic wave shielding body according to the invention, it is preferable to use the transparent laminate (H) in which the transparent electrically conductive layer (D) that is a multi-layered thin film is formed on one major surface of the polymer film (B).

[0128] A preferable transparent electrically conductive layer (D) according to the invention is formed by firstly laminating a repeating unit (Dt)/(Dm) comprising a high-refractive-index transparent thin film layer (Dt) and one metallic thin film layer (Dm) in this order on the polymer film (B) while repeating such repeating unit from 2 times to 4 times and, then, further, laminating at least one high-refractive-index transparent thin film layer (Dt) on the resultant laminate, is characterized in that a surface resistance thereof is from 0.1 to 5 Ω/square, and has properties excellent in low resistivity for electromagnetic wave shielding capacity, near-infrared ray cutting-off capacity, transparency, and visible light ray reflectance. Further, unless otherwise stated, the term “multi-layered thin film” as used herein is intended to include a transparent electrically conductive film of a multi-layered lamination in which at least one layer of a laminate constitution where a metallic thin film layer is interposed between the high-refractive-index transparent thin film layers is superimposed.

[0129] In the transparent electrically conductive layer according to the invention, the repeating unit is preferably laminated from 2 times to 4 times. That is, the transparent laminate (D) according to the invention in which the transparent electrically conductive layer is laminated on one major surface of the polymer film (B) has a layer constitution of (B)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt), (B)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt) or (B)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt)/(Dm)/(Dt). When the repeating unit is laminated more than 5 times, a restriction on a production apparatus and productivity becomes a serious problem, and, further, there is a tendency in which the visible light ray transmittance is deteriorated and the visible light ray reflectance is increased. On the other hand, when a repeating time is one time, it is difficult to simultaneously satisfy the low resistivity, the near-infrared ray cutting-off capacity and the visible light ray reflectance.

[0130] Further, the present inventors have found that, in the multi-layered thin film in which the repeating unit is laminated from 2 times to 4 times, in order to allow the near-infrared ray cutting-off capacity, the visible light ray transmittance, and the visible light ray reflectance to be characteristics simultaneously advantageous to the plasma display, a surface resistance thereof is from 0.1 to 5 Ω/square.

[0131] Further, it is conceivable that an electromagnetic wave intensity to be emitted from the plasma display is lowered in the future. In such a case, it is anticipated that, even when the surface resistance of the electromagnetic wave shielding body is from 5 to 15 Ω/square, sufficient electromagnetic wave shielding characteristics can be obtained. It is also conceivable that the electromagnetic wave intensity to be emitted from the plasma display is further lowered. In such a case, it is also anticipated that, even when the surface resistance of the electromagnetic wave shielding body is from 15 to 30 Ω/square, sufficient electromagnetic wave shielding characteristics can be obtained. On the other hand, it is also conceivable that, based on a different point of view from an emitted electromagnetic wave intensity, when a larger screen and a smaller thickness of the plasma display is required for, the surface resistance of the electromagnetic wave shielding body is required to be from 0.01 to 1 Ω/square.

[0132] As a material of the metallic thin film layer (Dm), silver is advantageous because it is excellent in electric conductivity, an infrared reflection property and visible light ray transmittance when it is laminated in multiple layers However, silver lacks chemical and physical stability whereupon it tends to be deteriorated under actions of a contaminant, water vapor, heat, light and other factors present in the environment. Accordingly, an alloy composed of silver and at least one metal, having high environmental stability, for example, gold, platinum, palladium, copper, indium, tin or the like, and a metal which is stable to these environmental factors can favorably used. Particularly, gold and palladium are favorable because these metals are excellent in environmental resistance and optical characteristics.

[0133] Although no particular limitation is placed on a content of silver in such a silver-containing alloy, it is desirable that the electric conductivity and optical characteristics thereof do not differ substantially from those of the silver thin film; on this occasion, the content is in a range of from about 50% by weight or more to less than about 100% by weight. However, since an addition of another metal to silver ordinarily impairs an excellent electric conductivity and optical characteristics of silver, it is desirable that, when a plurality of metallic thin film layers are employed, if possible, at least one of the metallic thin film layers uses silver without allowing silver to be an alloy thereof, or only a metallic thin film layer on a first layer and/or an outermost layer as viewed from the substrate is allowed to be an alloy.

[0134] Thickness of the metallic thin film layer (Dm) is determined by optical design and experiment, on the basis of electric conductivity, optical characteristics and the like. No particular limitation is placed on the thickness thereof, provided that the transparent electrically conductive layer has required characteristics. However, it is necessary, based on electric conductivity and the like, that a thin film is not of an island type structure, but in a continuous state and is preferably 4 nm or more. When the metallic thin film layer is unduly thick, there occurs a problem in transparency; therefore, it is preferably 30 nm or less. When a multiple of the metallic thin film layers exist, all of such layers are not necessarily of the same thickness and do not necessarily comprise silver or an alloy thereof.

[0135] In order to deposit the metallic thin film layer (Dm), there may be employed any of conventionally known methods such as sputtering, ion plating, vacuum deposition, and metal plating.

[0136] No particular limitation is placed on the transparent type film constituting the high-refractive-index transparent thin film layer (Dt), so long as the transparent thin film has transparency in a visible region and have an effect of preventing light reflection in the visible region of the metallic thin film layer; however, a high-refractive-index material having a refractive index of not less than 1.6, preferably not less than 1.8, and more preferably not less than 2.0 against a visible light ray is used. Specific examples of materials which form such a transparent thin film include oxides of metals such as indium, titanium, zirconium, bismuth, tin, zinc, antimony, tantalum, cerium, neodymium, lanthanum, thorium, magnesium, and gallium; mixtures of these metal oxides; and zinc sulfide.

[0137] In these oxides and the sulfide, the metal and an oxygen atom or a sulfur atom may be present in nonstoichiometric proportions; however, the oxides and the sulfide are permissible, so long as optical characteristics thereof are not substantially modified. Among the materials, zinc oxide, titanium oxide, indium oxide, and a mixture of indium oxide and tin oxide (ITO) are advantageously used because they not only have high transparency and a high refractive index, but also has a high-speed film formation, good adhesion to the metallic thin film layer and the like.

[0138] Thickness of the high-refractive-index transparent thin film layer (Dt) can be determined by an optical design and an experiment, on the basis of the optical characteristics of the polymer film (B) (hereinafter referred to also as “transparent substrate”), thickness and optical characteristics of the metal thin film layer, a refractive index of the transparent thin film layer, and the like; on this occasion, although no particular limitation is placed on the thickness thereof, it is preferably in a range of from 5 to 200 nm and more preferably from 10 to 100 nm. Respective thickness of high-refractive-index transparent thin film layers of from a first layer to a (n+1)th layer (n being equal to or larger than 1) are not necessarily the same thereamong and, further, the high-refractive-index transparent thin film layers are not necessarily made of the same transparent thin film material.

[0139] In order to form the high-refractive-index transparent thin film layer (Dt), there may be employed any of conventionally known methods such as sputtering, ion plating, ion beam assisted deposition, vacuum deposition, and wet coating.

[0140] In order to improve the environmental resistance of the transparent electrically conductive layer (D), any desired protective layer of an organic material or an inorganic material may be provided on a surface of the transparent electrically conductive layer to such an extent as does not detract from the electric conductivity and optical characteristics thereof. Further, in order to improve the environmental resistance of the metallic thin film layer, the adhesion between the metallic thin film layer and the high-refractive-index transparent thin film layer and the like, any desired inorganic material layer may be formed between the metallic thin film layer and the high-refractive-index transparent thin film layer to such an extent as does not detract from the electric conductivity and the optical characteristics thereof. Specific examples of these inorganic materials include copper, nickel, chromium, gold, platinum, zinc, zirconium, titanium, tungsten, tin, and palladium and, further, alloys composed of two or more of these metals. Thickness thereof is preferably in a range of from about 0.2 nm to about 2 nm.

[0141] In order to obtain a transparent electrically conductive layer (D) having desired optical characteristics, a thin film material of each layer, a number of layers, film thickness of each layer and the like may be determined by performing an optical design which utilizes a vector method using optical constants (refractive index and extinction coefficient) of the transparent polymer film (B) and the thin film material, a method using an admittance diagram and the like while taking into consideration electric conductivity, that is, a type and thickness of the material of the metallic thin film needed for the electromagnetic wave shielding capacity to be aimed for. In this occasion, it is preferable that an adjacent layer which is formed on the transparent electrically conductive layer (D) is taken into consideration. This is attributable to the fact that, since an entrance medium for light entering the transparent electrically conductive layer formed on the transparent polymer film (B) is different from an entrance medium having a refractive index of 1 such as air and vacuum, a transmitted light color (as well as transmittance, reflected light color and reflectance) undergoes changes. Namely, in a case in which the transparent adhesive layer (C) is interposed when the functional transparent layer (A) is formed on the transparent electrically conductive layer (D), designing is performed while taking into consideration an optical constant of the transparent adhesive layer (C). Further, when the functional transparent layer (A) is disposed directly on the transparent electrically conductive layer (D), designing is performed while taking into consideration the optical constant of a material which contacts the transparent electrically conductive layer (D).

[0142] It has been found that, by designing the transparent electrically conductive layer (D) in such a manner as described above, when a bottom layer and a top layer as viewed from the polymer film (B) are thinner than any other layer interposed therebetween in the high-refractive-index transparent thin film layer (Dt), or a bottom layer as viewed from the polymer film (B) is thinner than any other layer in the metallic thin film layer (Dm), and an adhesive which has a refractive index of from 1.45 to 1.65, a thickness of from 10 to 50 μm and an extinction coefficient of about 0 is an adjacent layer, reflectance of the transparent laminate is not significantly increased, that is, an increase of interfacial reflectance by forming the adjacent layer is 2% or less.

[0143] It has been found that, particularly in the transparent electrically conductive layer composed by repeating the repeating unit 3 times, that is, by 7 layers, when a second layer in the midst of the metallic thin film layer (Dm) composed of 3 layers is thicker than any other layer, in a case in which the adhesive is the adjacent layer, reflectance of the transparent laminate is not significantly increased.

[0144] Further, the optical constant can be measured by using an ellipsometry (elliptically polarized light analytical method) or an Abbe refractometer and, further, film formation can be performed by controlling a number of layers, film thickness and the like while observing the optical characteristics.

[0145] An atomic composition of the transparent electrically conductive layer formed in such a manner can be measured according to a method such as Auger electron spectroscopy (AES) inductively coupled plasma (ICP), and Rutherford backscattering spectrometry (RBS). Further, a layer construction and film thickness can be measured by observation in a depth direction by means of Auger electron spectroscopy, observation of a cross-section under a transmission type electron microscope, or the like.

[0146] The film thickness is controlled by carrying out film formation on the basis of the previously established relationship between the film-forming conditions and the film formation rate, or by monitoring the film thickness during film formation by means of a quartz oscillator or the like.

[0147] Except for a method of using the transparent electrically conductive thin film, there is also a method of using a electrically conductive mesh as the transparent electrically conductive layer. Although a mono-layer metallic mesh is described below as an example of the electrically conductive mesh, the electrically conductive mesh according to the invention is not limited to this example.

[0148] In the mono-layered metallic mesh, a copper mesh layer is ordinarily formed on a polymer film. Ordinarily, a copper foil is bonded on the polymer film and, then, the resultant copper foil-bonded polymer film is processed to be in a mesh state.

[0149] Both of flat-rolled copper and electrolytic copper are usable as the copper foil to be employed in the invention; however, porous metallic layer is preferably used and, on this occasion, a pore diameter thereof is preferably from 0.5 to 5 μm, more preferably from 0.5 to 3 μm, and still more preferably from 0.5 to 1 μm. When the pore diameter is larger than these pore diameters, there is a fear of causing a problem in patterning, whereas, when the pore diameter is smaller than these pore diameters, it is difficult to expect an enhancement of light ray transmittance. Further, porosity of the copper foil is in a range of preferably from 0.01 to 20% and more preferably from 0.02 to 5%. The term “porosity” as used herein is intended to include a value specified by P/R, wherein R represents a volume; and P represents a pore volume. For example, provided that, when the pore volume of the copper foil agsinst 0.1 cc of the volume thereof is measured by mercury porosity, the pore volume is 0.001 cc, the porosity can be defined as 1%. On this occasion, the copper foil to be used may be such a copper foil as has been subjected to any type of surface treatments. Specific examples of the surface treatments include chromate processing, surface roughening, pickling, and zinc/chromate processing.

[0150] Thickness of the copper foil is preferably from 3 to 30 μm, more preferably from 5 to 20 μm, and still more preferably from 7 to 10 μm. When the thickness is more than these thickness, there occurs a problem that a prolonged time is required for etching, while, when the thickness is less than these thickness, there occurs a problem that electromagnetic wave shielding capacity is deteriorated.

[0151] An open area ratio of a light transmission part is from 60% to 95%, and more preferably from 65% to 90%, and still more preferably from 70% to 85%. A shape of an open area portion is not particularly limited, but it is preferable that the shape thereof is in a form of an regular triangle, a regular tetragon, a regular hexagon, a circle, a rectangle, a rhombus, or the like, shapes of such open area portions are all alike and the open area portions are aligned within a surface thereof. As for a representative size of the open area portion of the light transmission part, it is preferable that a side or a diameter thereof is in a range of, preferably from 5 to 200 μm, and more preferably from 10 to 150 μm. When the size is unduly large, the electromagnetic wave shielding capacity is deteriorated, while, when the size is unduly small, an unfavorable influence will be given to an image on a display. Further, it is preferable that width of a metal in other portions than the open area portions is preferably from 5 to 50 μm. Namely, a pitch is preferably from 10 to 250 μm. When the pitch is smaller than such a width, forming itself becomes extremely difficult, while, when the pitch is larger than such width, an unfavorable influence will be given to the image.

[0152] A substantial sheet resistance of a metallic layer having the light transmission part, as used herein, is a sheet resistance measured by a 4-terminal method having an interval between electrodes at least 5 times as large as the repeating unit of the pattern by utilizing an electrode at least 5 times as large as the pattern. For example, when the open area portion has a shape of a regular tetragon having a side of 100 μm, and are regularly aligned, while the metallic layer is 20 μm wide, measurements can be conducted by disposing electrodes each having a diameter of 1 mm with an interval of 1 mm therebetween. Alternatively, a pattern-bearing film is processed to be in strip form and, then, electrodes are disposed at both ends thereof in a longitudinal direction and, thereafter, resistance (R) thereof is measured to obtain the expression: the substantial sheet resistance=R×b/a, wherein a represents length in a longitudinal direction; and b represents length in a transverse direction. A value obtained in such a manner as described above is preferably from 0.01 Ω/square to 0.5 Ω/square, and more preferably from 0.05 Ω/square to 0.3 Ω/square. When a value which is smaller than these values is tried to obtain, the film becomes unduly thick to be unable to sufficiently obtain the opening area portion, while, when a value becomes larger than these values, sufficient electromagnetic wave shielding capacity can not be obtained.

[0153] As for a method of laminating a silver foil on a polymer film, a transparent adhesive is used. Examples of adhesives include those of an acrylic type, a urethane type, a silicone type, and a polyester type; however, adhesives are not particularly limited to these types. A two-component type and a thermosetting type are favorably used. Further, it is preferable that the adhesive is excellent in chemical resistance. It is permissible that, after the adhesive is applied to the polymer film, the silver foil can be bonded to the resultant adhesive-applied polymer film, or the silver foil is applied with the adhesive and then bonded.

[0154] As for a method of forming the light transmission part, a printing method and a photo-resist method can be used. In the printing method, it is of a common practice to allow a mask layer to form a pattern by a screen printing method utilizing a printing resist material. In a method of using a photo-resist material, the photo-resist material is solidly formed on a metallic foil by a roll coating method, a spin coating method, an entire-surface printing method, a transfer printing method, or the like and, then, is exposed to light and developed by using photomask to perform resist patterning. After the resist patterning is completed, a metallic portion which will be an opening area portion is removed by a wet etching method whereby a metallic mesh having the light transmission part of a desired opening area shape and opening area ratio can be obtained.

[0155] 4. Transmission Characteristics

[0156] Visible light ray transmittance in a light transmission portion of an electromagnetic wave shielding body is preferably from 30 to 85%, and more preferably from 50 to 80%. When the visible light ray transmittance is less than 30%, luminance is unduly decreased to deteriorate visibility. Further, in order to obtain contrast, there are some cases in which it is necessary that the visible light ray transmittance is 85% or less, and more preferably 80% or less.

[0157] Further, the visible light ray transmittance in a light control film is preferably from 55 to 90%, and more preferably from 60 to 85%. When the visible light ray transmittance is less than 55%, the luminance is unduly decreased to deteriorate the visibility. Further, in order to obtain contrast, there are some cases in which it is necessary that the visible light ray transmittance is 85% or less, and more preferably 80% or less.

[0158] Further, As used herein, the visible light ray transmittance (Tvis) and the visible light ray reflectance (Rvis) are calculated in accordance with JIS (R-3106) on the basis of the wavelength dependence of transmittance and reflectance.

[0159] 5. Color Characteristics and Dye

[0160] When a transmitted color of a display filter is rich in a tint of from yellowish green tint to green, contrast of the display is decreased and, further, color purity thereof is deteriorated and a white color representation sometimes becomes greenish. This phenomenon is attributable to the fact that light in a wavelength of around 550 nm which is a yellowish green color to green color is the highest in visibility.

[0161] When the visible light ray transmittance and the visible light ray reflectance in a multi-layered film are taken into serious consideration, the multi-layered thin film ordinarily lacks in a transmitted color tone. As the electromagnetic wave shielding capacity, that is, electric conductivity and near-infrared ray cutting-off capacity becomes larger, it becomes necessary to allow a total thickness of a metallic thin film to be larger. However, as the total thickness of the metallic thin film becomes larger, there is a tendency in which the color becomes more of from a green color to a yellowish green color. Therefore, it is required that, in the electromagnetic wave shielding body used for a plasma display, the transmitted color thereof is neutral gray or blue gray. This is attributable to a deterioration of the contrast due to strong green color transmission, weak luminescence of blue color compared with that of red or green color, a preference for white color having a slightly higher color temperature than that of a standard white color, and the like. Further, it is desirable that, as the transmission characteristics of the electromagnetic wave shielding body, a chromaticity coordinate of white color representation on the plasma display is as near to a blackbody locus as possible.

[0162] When the multi-layered thin film is used in the transparent electrically conductive layer (D), it is important to allow the transmitted color of the electromagnetic wave shielding body to be neutral gray or blue gray by correcting a color tone of the multi-layered thin film. Such a correction of the color tone can be performed if only a dye having absorption in a visible wavelength region is used. For example, when an greenish tint exists in the transmitted color of the transparent electrically conductive layer (D), the correction to gray can be performed by using a dye of red color, while, when a yellowish tint exists in the transmitted color, the correction can be performed by using a dye of from blue to violet color.

[0163] In a color plasma display, a red color luminescent phosphor such as (Y, Gd, Eu)BO ₃ , a green color luminescent phosphor such as (Zn, Mn) ₂ SiO ₄ , and a blue color luminescent phosphor such as (Ba, Eu)MgA ₁₀ O ₁₇ : Eu which emit light by being excited by a vacuum ultraviolet light that is generated by direct or alternating electric current discharge in a rare gas are formed in display cells which constitute pixels. The phosphors are selected on a basis of color purity, a coating property to a discharge cell, a short period of residual luminescent time, luminous efficiency, thermal resistance and the like whereupon many of the phosphors now in practical use have yet to be improved in color purity thereof. Particularly, emission spectrum of the red color luminescent phosphor indicates several luminescent peaks over a wavelength range of from about 580 nm to about 700 nm whereupon, since a luminescent peak in a side of a relatively intense short wavelength is luminescence of from yellow color to orange color, there occurs a problem in which color purity of red color luminescence is deteriorated to approach to that of orange color luminescence. When a mixed gas of Xe and Ne is used as a rare gas, the color purity of the orange color luminescence brought about by radiative relaxation of an Ne-excited state is also deteriorated. As to green color luminescence and blue color luminescence, a position of a peak wavelength and broadness of luminescence are factors of deteriorating the color purity thereof.

[0164] Height of the color purity can be indicated, for example, in terms of an area of color reproduction gamut which is shown by an area of a triangle formed by connecting 3 vertices of red, green and blue colors in a coordinate system defined by Commission Internationale d'Eclairage (CIE) in which hue and saturation are represented by abscissa chromaticity x and ordinate chromaticity y, respectively. Due to a low color purity, the color reproduction gamut of luminescence of the plasma display is narrower than that which is shown by chromaticity of 3 colors of RGB defined by an NTSC (National Television System Committee) system.

[0165] Further, not only migration of luminescence between display cells, but also a state, in which luminescence of each color contains a broad range of unnecessary light thereby allowing necessary light to be obscure, becomes a factor of deteriorating color purity as well as contrast of the plasma display. Further, the contrast of the plasma display is ordinarily deteriorated at a bright time in which external light emitted from, for example, lighting equipment and the like is present in a room compared with a dark time. This is attributable to the fact that a substrate glass, a phosphor and the like reflect the external light whereupon unwanted light prevents necessary light from being conspicuous. A contrast ratio of the plasma display panel is from 100 to 200 at the dark and from 10 to 30 at the time of the bright occasion of about 100 lx of an environmental luminance whereupon an improvement thereof becomes a target to be pursued. The fact that the contrast is low is also a factor of narrowing the color reproduction gamut.

[0166] In order to enhance the contrast, there is a method in which a neutral density (ND) filter is provided in front of the display thereby decreasing transmission over an entire visible wavelength region to reduce the reflection of the external light and the like at the substrate glass or the phosphor; however, in this method, when the visible light ray transmittance is significantly low, luminance and sharpness of the image are deteriorated whereupon no significant improvement on the color purity is not noticed.

[0167] The present inventors have found that enhancement of the color purity and contrast of the luminescent color of the color plasma display can be achieved by decreasing the unwanted luminescence and the reflection of the external light which cause to deteriorate the color purity and contrast of the luminescent color.

[0168] Further, the present inventors have found that an application of a dye is capable of not only controlling color of the electromagnetic wave shielding body to be neutral gray or neutral blue but also decreasing the unwanted luminescence and the reflection of the external light which cause to deteriorate the color purity and contrast of the luminescent color. Furthermore, the present inventors have found that this is particularly conspicuous when the red color luminescence is near to orange and that the color purity of the red color luminescence can be improved by decreasing the luminescence in a wavelength of from 580 nm to 605 nm which causes such deterioration.

[0169] In the display filter according to the invention, decrease of the unwanted luminescence and reflection of the external light can be conducted by allowing a dye having an absorption maximum in a wavelength of from 570 nm to 605 nm to be contained in the shielding body. On this occasion, it is necessary that transmission of light in a wavelength range of from 615 nm to 640 nm in which luminescence peak indicating a red color exists is not markedly impaired.

[0170] Ordinarily, a dye has a broad absorption range whereupon there is a risk in which even a dye having a desired absorption peak absorbs luminescence in a favorable wavelength as well by absorbing a trailing end portion thereof simultaneously. When luminescence by Ne is present, orange color luminescence can be decreased to enhance the color purity of the luminescence from RGB display cells.

[0171] Further, green color luminescence of the color plasma display has a broad band and there is a case in which a peak position thereof exists, for example, in a side of somewhat longer wavelength than that of green color required by the NTSC system, that is, in a side of yellowish green.

[0172] The present inventors have found that the color purity can be enhanced by absorption of a short wavelength side of a dye having an absorption maximum at a wavelength of from 570 nm to 605 nm thereby absorb-trimming a long wavelength side of the green color luminescence and, further, trimming the unwanted luminescence, and/or shifting the peak.

[0173] In order to enhance the color purity of the red color luminescence as well as green color luminescence, it is preferable that minimum transmittance of the electromagnetic wave shielding body in a wavelength of from 570 nm to 605 nm is allowed to be 80% or less against a required transmittance of the red color luminescence at a peak position by using a dye having an absorption maximum in a wavelength of from 570 nm to 605 nm.

[0174] When the color purity of the blue color luminescence is low, the unwanted luminescence is decreased, a peak wavelength is shifted and a dye to absorb bluish green color luminescence may be used, in the same manner as in the cases of red color luminescence and green color luminescence. Further, absorption by the dye decreases incidence of an external light into the phosphor thereby allowing the reflection of the external light on the phosphor to be decreased. These procedures can also enhance the color purity and contrast.

[0175] As a method of allowing a dye to be contained in the display filter according to the invention, there is a method which uses at least one state selected from the group consisting of: (1) a polymer film in which at least one type of dye is kneaded in a transparent resin; (2) a polymer film prepared by first emulsify-dissolving at least one type of dye in a concentrated resin solution of a resin or a resin monomer/an organic solvent and, then, subjecting the resultant concentrated resin solution containing the dye to casting processing; (3) a material prepared by first adding at least one type of dye to a mixture of a resin binder and an organic solvent to prepare a coating material and, then, applying the thus-prepared coating material on a transparent substrate; and (4) a transparent adhesive containing at least one type of dye.

[0176] The term “contain” as used herein is intended to include states of being contained in a substrate, in a layer such as a coating film and in an adhesive as well as states of being coated on surfaces of the substrate and the layer.

[0177] As dyes, ordinary dyes or pigments which have a desired absorption wavelength in a visible region may be permissible. Types thereof are not particularly limited; however, examples of such dyes and pigments include organic dyes which are ordinarily available in the market such as those of an anthraquinone type, a phthalocyanine type, a methine type, an azomethine type, an oxazine type, an azo type, a styryl type, a coumarin type, a porphyrin type, a dibenzofuranone type, a diketopyrrolopyrrole type, a rhodamine type, and a xanthene type, a pyrromethene type. The type and concentration thereof are determined depending on an absorption wavelength/absorption coefficient of the dye, a tone of a transparent electrically conductive layer, transmission characteristics/transmittance required for the electromagnetic wave shielding body, a medium for dispersing the dye, a type/thickness of a coating film and the like; on this occasion, the type and concentration are not particularly limited.

[0178] When a multi-layered thin film is used in the transparent electrically conductive layer (D), in a case in which, though the near-infrared ray cutting-off capacity as well as the electromagnetic wave shielding capacity is held, higher near-infrared ray cutting-off capacity is required, or in another case in which the transparent electrically conductive layer does not hold the near-infrared ray cutting-off capacity, it is permissible to use one or more types of near-infrared absorption dyes together with the dyes described above in order to impart the display filter with the near-infrared ray cutting-off capacity.

[0179] No particular limitation is placed on the near-infrared absorbing dye, so long as it can supplement the near-infrared ray cutting-off capacity of the transparent electrically conductive layer and can absorb an intense near-infrared ray emitted from the plasma display to such an extent as is suitable for practical purposes; further, no particular limitation is placed on the concentration of the near-infrared absorbing dye. Examples of such near-infrared absorbing dyes include compounds of a phthalocyanine type, anthraquinone type, a dithiol type, and a diiminium type.

[0180] Since a temperature of a panel surface of the plasma display panel is high and a temperature of the electromagnetic wave shielding body goes up particularly in a high temperature atmosphere, it is preferable that the dye to be used in the invention has thermal resistance, for example, such that it does not significantly deteriorate itself by being decomposed at 80° C. or the like.

[0181] Further, there are some dyes which are deficient in light resistance as well as thermal resistance. When deterioration thereof by luminescence of the plasma display or an ultraviolet ray/a visible light ray of the external light comes to be a problem, it is important to decrease deterioration of the dye to be caused by the ultraviolet ray or the visible light ray by using a member which contains an ultraviolet ray absorbing agent or another member which does not allow an ultraviolet ray to pass through, or to use a dye which is not significantly deteriorated by the ultraviolet ray or the visible light ray. The same is true with cases of heat, light, moisture and a mixed environment thereof. When the dye is deteriorated, the transmission characteristics of the electromagnetic wave shielding body are changed.

[0182] As a practical matter, a case in which the surface temperature of the plasma display panel goes up to a range of from 70° C. to 80° C. is stipulated in Japanese Unexamined Patent Publication JP-A 8-220303 (1996). Further, light emitted from the plasma display panel is stipulated, for example, as 300 cd/m ² (Fujitsu Limited, Image Site, Catalog AD 25-000061C Oct., 1997M) whereupon, when light having this value is irradiated for 20,000 hours provided that a solid angle is 2π, such irradiation comes to be 2π×20,000×300=38,000,000 (lx·hr); therefore, it is understood that light resistance of several ten millions (lx·hr) is practically required.

[0183] Further, in order to disperse a dye in a medium or a coating film, a dissolving property thereof into an appropriate solvent is important. It is permissible to allow two or more types of dyes having different absorption wavelengths from each other to be contained in one medium or coating film.

[0184] The display filter according to the invention has excellent transmission characteristics/transmittance which do not significantly impair luminance/visibility of the color plasma display and can enhance color purity and contrast of luminescent color of the color plasma display. The present inventors have found that, when at least one of one or more types of dyes which are to be contained is a tetraazaporphyrin compound, since the tetraazaporphyrin compound has a major absorption wavelength in a wavelength the same as or similar to that of unwanted luminescence of from 570 to 605 nm which is particularly required to be decreased and has a comparatively small absorption wavelength band, loss of luminance derived from absorption of favorable luminescence can be reduced; hence, a display filter which is excellent in capacity for enhancing transmission characteristics/transmittance, color purity and contrast of luminescence color was able to be obtained.

[0185] The tetraazaporphyrin compound used in the invention can be expressed by the foregoing formula (1). The formula (1) will hereinafter be also abbreviated as the following structural formula (2): 2

[0186] wherein A ^m and A ⁿ each individually represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, an amino group, a carboxyl group, a sulfonic acid group, an alkyl group having carbon atoms of from 1 to 20, a halogenoalkyl group, an alkoxy group, an alkoxyalkoxy group, an aryloxy group, a monoalkylamino group, dialkylamino group, an aralkyl group, an aryl group, a heteroaryl group, an alkylthio group, or arylthio group; A ^m and A ⁿ each individually may form a ring except an aromatic ring via a connecting group; and M represents two hydrogen atoms, a divalent metal atom, a trivalent metal atom having one substituent, a tetravalent metal atom having two substituents, or an oxy metal atom.

[0187] Specific examples of the tetraazaporphyrin compound expressed by the formula (1) are described below. In the formula, specific examples of from A ¹ to A ⁸ include a hydrogen atom; halogen atoms such as fluorine, chlorine, bromine and iodine atom; a nitro group; a cyano group; a hydroxy group; an amino group; a carboxyl group; a sulfonic acid group; linear-chain, branched-chain or cyclic alkyl groups each having carbon atoms of from 1 to 20 such as a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, aniso-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, a 2-methylbutyl group, a 1-methylbutyl group, aneo-pentyl group, a 1,2-dimethylpropyl group, a 1,1-dimethylpropyl group, a cyclo-pentyl group, an n-hexyl group, a 4-methylpentyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 1-methylpentyl group, a 3,3-dimethylbutyl group, a 2,3-dimethylbutyl group, a 1,3-dimethylbutyl group, a 2,2-dimethylbutyl group, a 1,2-dimethylbutyl group, a 1,1-dimethylbutyl group, a 3-ethylbutyl group, a 2-ethylbutyl group, a 1-ethylbutyl group, a 1,2,2-trimethylbutyl group, a 1,1,2-trimethylbutyl group, a 1-ethyl-2-methylpropyl group, a cyclo-hexyl group, an n-heptyl group, a 2-methylhexyl group, a 3-methylhexyl group, a 4-methylhexyl group, a 5-methylhexyl group, a 2,4-dimethylpentyl group, an n-octyl group, a 2-ethylhexyl group, a 2,5-dimethylhexyl group, a 2,5,5-trimethylpentyl group, a 2,4-dimethylhexyl group, a 2,2,4-trimethyl pentyl group, an n-nonyl group, a 3,5,5-trimethylhexyl group, an n-decyl group, a 4-ethyloctyl group, a 4-ethyl-4,5-dimethylhexyl group, an n-undecyl group, an n-dodecyl group, a 1,3,5,7-tetramethyloctyl group, a 4-butyloctyl group, a 6,6-diethyloctyl group, an n-tridecyl group, a 6-methyl-4-butyloctyl group, a n-tetradecyl group, an n-pentadecyl group, a 3,5-dimethylheptyl group, a 2,6-dimethylheptyl group, a 2,4-dimethylheptyl group, a 2,2,5,5-tetramethylhexyl group, a 1-cyclo-pentyl-2,2-dimethylpropyl group, and a 1-cyclo-hexyl-2,2-dimethylpropyl group;

[0188] halogenoalkyl groups each having carbon atoms of from 1 to 20 such as a chloromethyl group, a dichloromethyl group, a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and a nonafluorobutyl group;

[0189] alkoxy groups each having carbon atoms of from 1 to 20 such as a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, an iso-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentoxy group, an iso-pentoxy group, a neo-pentoxy group, an n-hexyloxy group, and an n-dodecyloxy group;

[0190] alkoxyalkoxy groups each having carbon atoms of from 2 to 20 such as a methoxyethoxy group, an ethoxyethoxy group, a 3-methoxypropyloxy group, and a 3-(iso-propyloxy)propyloxy group;

[0191] aryloxy groups each having carbon atoms of from 6 to 20 such as a phenoxy group, a 2-methylphenoxy group, a 4-methylphenoxy group, a 4-t-butylphenoxy group, a 2-methoxyphenoxy group, and a 4-iso-propylphenoxy group;

[0192] a monoalkylamino groups each having carbon atoms of from 1 to 20 such as a methylamino group, an ethylamino group, an n-propylamino group, an n-butylamino group, and an n-hexylamino group;

[0193] dialkylamino groups each having carbon atoms of from 2 to 20 such as dimethylamino group, diethylamino group, a di-n-propylamino group, a di-n-butylamino group, and an N-methyl-N-cyclohexylamino group;

[0194] aralkyl groups each having carbon atoms of from 7 to 20 such as a benzyl group, a nitrobenzyl group, a cyanobenzyl group, a hydroxybenzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a dichlorobenzyl group, a methoxybenzyl group, an ethoxybenzyl group, a trifluoromethylbenzyl group, a naphthylmethyl group, a nitronaphthylmethyl group, a cyanonaphthylmethyl group, a hydroxynaphthylmethyl group, a methylnaphthylmethyl group, and a trifluoromethylnaphthylmethyl group;

[0195] aryl groups each having carbon atoms of from 6 to 20 such as a phenyl group, a nitrophenyl group, a cyanophenyl group, a hydroxyphenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a dichlorophenyl group, a methoxyphenyl group, an ethoxyphenyl group, a trifluoromethylphenyl group, an N,N-dimethylaminophenyl group, a naphthyl group, a nitronaphthyl group, a cyanonaphthyl group, a hydroxynaphthyl group, a methylnaphthyl group, and a trifluoromethylnaphthyl group; heteroaryl groups such as a pyrrolyl group, a thienyl group, a furanyl group, an oxazoyl group, an isoxazoyl group, an oxadiazoyl group, an imidazoyl group, a benzoxazoyl group, a benzothiazoyl group, a benzimidazoyl group, a benzofuranyl group, and an indoyl group;

[0196] alkylthio groups each having carbon atoms of from 1 to 20 such as a methylthio group, an ethylthio group, an n-propylthio group, an iso-propylthio group, an n-butylthio group, an iso-butylthio group, a sec-butylthio group, a t-butylthio group, an n-pentylthio group, an iso-pentylthio group, a 2-methylbutylthio group, a 1-methylbutylthio group, a neo-pentylthio group, a 1,2-dimethylpropylthio group, and a 1,1-dimethylpropylthio group; arylthio groups each having carbon atoms of from 6 to 20 such as a phenylthio group, a 4-methylphenylthio group, a 2-methoxyphenylthio group, and a 4-t-butylphenylthio group.

[0197] Examples in which combinations of A ¹ and A ² , A ³ and A ⁴ , A ⁵ and A ⁶ , and A ⁷ and A ⁸ each form a ring via a connecting group include —CH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ CH ₂ CH(NO ₂ )CH ₂ —, —CH ₂ CH(CH ₃ )CH ₂ CH ₂ —, and —CH ₂ CH(Cl)CH ₂ CH ₂ —.

[0198] Examples of divalent metals shown as M include Cu, Zn, Fe, Co, Ni, Ru, Rh, Pd, Pt, Mn, Sn, Mg, Hg, Cd, Ba, Ti, Be, and Ca.

[0199] Examples of trivalent metals each having one substituent include Al—F, Al—Cl, Al—Br, Al—I, Ga—F, Ga—Cl, Ga—Br, Ga—I, In—F, InCl, In—Br, In—I, Tl—F, Tl—Cl, Tl—Br, Tl—I, Al—C ₆ H ₅ , Al—C ₆ H ₄ (CH ₃ ), In—C ₆ H ₅ , In—C ₆ H ₄ (CH ₃ ), Mn (OH), Mn (OC ₆ H ₅ ) Mn[OSi(CH ₃ ) ₃ ], and Fe—Cl, Ru—Cl.

[0200] Examples of tetravalent metals each having two substituents include CrCl ₂ , SiF ₂ , SiCl ₂ , SiBr ₂ , SiI ₂ , SnF ₂ , SnCl ₂ , SnBr ₂ , ZrCl ₂ , GeF ₂ , GeCl ₂ , GeBr ₂ , GeI ₂ , TiF ₂ , TiCl ₂ , TiBr ₂ , Si(OH) ₂ , Sn(OH) ₂ , Ge(OH) ₂ , Zr(OH) ₂ , Mn(OH) ₂ , TiA ₂ , CrA ₂ , SiA ₂ , SnA ₂ , and GeA ₂ , wherein A represents any one of an alkyl group, a phenyl group, a naphthyl group and a derivative thereof; and Si(OA′) ₂ , Sn(OA′) ₂ , Ge(OA′) ₂ , Ti(OA′) ₂ , and Cr(OA′) ₂ , wherein A′ represents any one of an alkyl group, a phenyl group, a naphthyl group, a trialkylsilyl group, a dialkylalkoxysilyl group and a derivative thereof; Si(SA″) ₂ , Sn(SA″) ₂ , and Ge(SA″) ₂ wherein A″ represents any one of an alkyl group, a phenyl group, a naphthyl group and a derivative thereof.

[0201] Examples of oxy metals include VO, MnO, and TiO.

[0202] Preferably, mentioned are Pd, Cu, Ru, Pt, Ni, Co, Rh, Zn, VO, TiO, Si(Y) ₂ , Ge(Y) ₂ , wherein Y represents any one of a halogen atom, an alkoxy group, an aryloxy group, an acyloxy group, a hydroxy group, an alkyl group, an aryl group, an alkylthio group, an arylthio group, a trialkylsilyloxy group, a trialkyl tin oxyo group, and a trialkyl germanium oxy group.

[0203] More preferably, mentioned are Cu, VO, Ni, Pd, Pt, and Co.

[0204] The present inventors have further found that, when the azaporphyrin compound expressed by the formula (1) is, for example, a tetra-t-butyl-tetraazaporphyrin complex or a tetra-neo-pentyl-tetraazaporphyrin complex, the compound is comparatively easily produced, a dissolving property thereof against a solvent and the complex itself are stable, the compound is excellent in absorption characteristics and, as a result of having been imparted with a t-butyl group or a tetra-neo-pentyl group, the compound is allowed to have a third dimensional form which enhances the dissolving property against a solvent and, accordingly, the dye has come to be easily contained and, on the basis of this finding, an excellent electromagnetic wave shielding body was able to be obtained.

[0205] In the display filter according to the invention, the methods (1) to (4) which allow the dye to be contained can be conducted in at least one layer selected from the group consisting of a polymer film (B) containing a dye, a transparent adhesive layer (C) or a second transparent adhesive layer containing a dye to be described below, a functional transparent layer (A) containing a dye to be described below, and the hard coat layer (F), containing a dye, which has been described above. The functional transparent layer (A) containing a dye to be described below may be any one of a film which contains a dye and, further, has various types of functions, a material in which a film which contains a dye and, further, has various types of functions is formed on a polymer film, and a material in which a film having various types of functions is formed on a substrate containing a dye.

[0206] Further, in the invention, at least two types of dyes having different absorption wavelengths from each other may be contained in a medium or a coating film, or at least two dye layers may be present.

[0207] First of all, a method (1) which comprises kneading a resin together with a dye and hot-molding the thus-kneaded resin will be described.

[0208] It is preferable to use a resin material which has transparency as high as possible when formed into a plastic plate or a polymer film. Specific examples of such resin materials include, but are not limited to, polyethylene terephthalate, polyether sulfone, polystyrene, polyethylene naphthalate, polyarylate, polyether ether ketone, polycarbonate, polyethylene, polypropylene, polyamides such as nylon 6, polyimides, cellulose type resins such as triacetylcellulose, polyurethane, fluorine-containing compounds such as polytetrafluoroethylene, vinyl compounds such as polyvinyl chloride, polyacrylic acid, polyacrylic esters, polyacrylonitrile, addition polymers of vinyl compounds, polymethacrylic acid, polymethacrylate, vinylidene compounds such as polyvinylidene chloride, copolymers of vinyl compounds or fluorine-containing compounds such as a vinylidene fluoride/trifluoroethylene copolymer, and an ethylene/vinyl acetate copolymer, polyethers such as polyethylene oxide, epoxy resins, polyvinyl alcohol, and polyvinyl butyral.

[0209] As to a preparation method, a processing temperature, a film-forming condition and the like may vary somewhat according to a dye used and a base polymer. However, usually employed are (i) a method in which a dye is mixed to powders or pellets of a base polymer, and the resulting mixture is heat-melted at a temperature of from 150 to 350° C. and formed into a plastic plate; (ii) a method in which a film is formed by an extruder; (iii) a method in which a raw film is prepared by an extruder and, then, uniaxially or biaxially stretched to a size 2 to 5 times an original size at a temperature of from 30 to 120° C. to form a film having a thickness of from 10 to 200 μm, and the like. An additive commonly used at the time of molding resins, such as a plasticizer, may be added during kneading. Although an amount of the dye to be added may vary according to absorption coefficient of the dye, thickness of a polymeric molded article to be made, intended absorption intensity, intended transmission characteristics/transmittance and the like, it usually ranges from 1 ppm to 20%, based on the weight of the polymeric molded article as a substrate.

[0210] In a casting method (2), a dye is add-dissolved in a concentrated solution of resin in which a resin or a resin monomer is dissolved in an organic solvent and, on this occasion, a plasticizer, a polymerization initiator, or an anti-oxidant is added, as desired, and the resultant concentrated solution is poured onto a mold or a drum which has a required surface contour to obtain a plastic plate or a polymer film through subsequent solvent evapolation/drying or polymerization/solvent evapolation/drying processing.

[0211] A resin selected from the group consisting of an aliphatic ester type resin, an acrylic type resin, a melamine resin, a urethane resin, an aromatic ester type resin, a polycarbonate resin, an aliphatic polyolefin resin, an aromatic polyolefin resin, a polyvinyl type resin, a polyvinyl alcohol resin, a polyvinyl-modified resin (PVB, EVA or the like) and a resin monomer of a copolymer resin thereof is usually used. As the solvent, there is used a solvent selected from the group consisting of solvents of a halogen type, an alcohol type, a ketone type, an ester type, an aliphatic hydrocarbon type, an aromatic hydrocarbon type, an ether type and a mixture type thereof.

[0212] Although a concentration of the dye may vary according to absorption coefficient of the dye, thickness of the plate or the film, intended absorption intensity, intended transmission characteristics/transmittance and the like, it is usually in a range of from 1 ppm to 20%, based on the weight of the resin monomer.

[0213] A concentration of the resin is usually in a range of from 1 to 90%, based on the entire coating material.

[0214] As to a method (3) which comprises preparing a coating material and, then, performing a coating operation, employed are a method in which a dye is dissolved in a binder resin and an organic solvent to prepare a coating material, a method in which a dye that has previously been pulverized (50 to 500 nm) is dispersed in an uncolored acrylic emulsion-based coating material to prepare an acrylic emulsion-based aqueous coating material and the like.

[0215] In the former method, a resin selected from the group consisting of an aliphatic ester type resin, an acrylic type resin, a melamine resin, a urethane resin, an aromatic ester type resin, a polycarbonate resin, an aliphatic polyol