JP2005238630A - Transparent laminate, filter for display, and plasma display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent laminate excellent in transparency, electromagnetic wave shielding properties, infrared cutting properties, and reflection preventing properties, a filter for a display, and a plasma display. <P>SOLUTION: The transparent laminate 1 has a transparent substrate 10 and a shield layer 40 in which thin transparent film layers 41a-41e and thin metal film layers 43a-43d are formed alternately. The number of the metal layers is n, and the number of the transparent layers is n+1 (n is an integer of 1 or greater). The surface resistance of the shield layer 40 is 4 Ω or below, the visible light transmittance is 40% or above, the luminous reflectance is 2% or below, and the transmittance of light greater than 800 nm in wavelength is 20% or below. The filter for the display has the laminate, and the plasma display has the laminate or the filter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a transparent laminate used as a front plate of a plasma display and a display filter. Furthermore, the present invention relates to a plasma display.

  In recent years, plasma displays have been attracting attention as being suitable for applications such as large-screen flat-screen TVs and thin-screen monitors and compatible with high-definition broadcasting. Since this plasma display uses a discharge phenomenon for its image display, it may generate a leakage electromagnetic field. However, in recent years, the leakage electromagnetic field may affect other devices. It has been pointed out. Therefore, it is required to suppress the leakage electromagnetic field within a predetermined reference value.

The standard value of the leakage electromagnetic field is indicated by the radiated electric field strength (unit: dB μV / m) which is an absolute value, and this radiated electric field strength is certified as VCCI class B for home use and class A for other uses. Need to get certified. Here, VCCI class B means that the radiation field strength in the frequency range of 30 to 230 MHz is 30 dBμV / m or less and the radiation field strength in the frequency range of 230 to 1000 MHz is 37 dBμV / m or less at a measurement distance of 10 m. Class A means that the radiation field strength in the frequency range of 30 to 230 MHz is 40 dBμV / m or less and the radiation field strength in the frequency range of 230 to 1000 MHz is 47 dBμV / m or less at a measurement distance of 10 m.
Generally, the radiated electric field intensity of a plasma display exceeds 40 dBμV / m for a diagonal 20-inch type and about 50 dBμV / m for a diagonal 40-inch type in a 20 to 100 MHz band. It is not possible.
Therefore, for example, when the radiation field intensity of the plasma display is 50 dBμV / m, an electromagnetic wave shielding body having a shielding effect of 10 dB or more for class A certification and 20 dB or more for class B certification is required.
Here, the shield effect (SE) is a value (unit: dB) representing the degree of attenuation of electromagnetic wave energy. This shielding effect is a relative evaluation represented by the following formula (1), and it can be said that the larger this value is, the more effective the shielding is. In the equation, Ei represents the incident electric field strength, Et represents the transmission electric field strength, that is, the electric field strength of the electromagnetic wave transmitted through the shield body, and the unit is V / m for both.
SE = 20 Log (Ei / Et) (1)

  In addition, the plasma display emits strong near infrared light due to excitation of gas species, and the near infrared light may act on an infrared remote controller such as a television or a video to cause a malfunction. Therefore, in the plasma display, it is required that light in the wavelength region of 800 to 1000 nm used for home video and infrared remote controllers of televisions is difficult to leak.

  As described above, in the plasma display, since it is required to suppress leakage of electromagnetic waves and near infrared rays emitted from the plasma display, a filter having electromagnetic shielding properties and near infrared cutting properties is attached to the front surface of the display. . As a matter of course, this filter must have excellent transparency with respect to the visible light region.

As a method for cutting near infrared rays, it is known to provide a near infrared absorption filter containing a near infrared absorption pigment. However, generally, near infrared absorption pigments are deteriorated by the environment such as humidity, heat, and light. There was a problem that optical characteristics such as near-infrared cutability and filter color tone change with time.
In addition, since the plasma display emits near infrared rays with high intensity over the entire near infrared wavelength region, it is necessary to use a near infrared absorption filter that can absorb near infrared rays over a wide wavelength region. However, in order to reduce the near-infrared transmittance to such an extent that it does not affect other devices, the type and amount of the dye contained in the filter must be increased, resulting in a decrease in visible light transmittance and cost. Increase became a problem.

As a method of shielding a leakage electromagnetic field (electromagnetic wave), a method of covering with a highly conductive object is known. In this method, a metal mesh or a metal fiber or synthetic resin mesh coated with metal is generally used. However, when the display is covered with these, there are problems such as generation of a portion that does not transmit light emitted from the plasma display, generation of moire fringes, and high cost due to poor yield.
Therefore, it has been studied to use a transparent conductive film such as a metal thin film or an oxide semiconductor thin film such as ITO for the electromagnetic wave shielding layer.

When a metal thin film is used as the transparent conductive film, the conductivity becomes high and the electromagnetic wave shielding property becomes high, but the metal reflects or absorbs light over a wide wavelength region, so that the visible light transmittance is high. It was difficult to get.
When an oxide semiconductor thin film is used as the transparent conductive film, the transparency is superior to that when a metal thin film is used. However, the surface resistance is 10 to 1000Ω, and the conductivity is inferior. There was a problem that was relatively high. Furthermore, the transparent conductive film made of ITO has not been obtained with a resistance that is low enough to shield an extremely high intensity electromagnetic wave emitted from a plasma display.

For these reasons, it has been proposed to use a multilayer thin film in which transparent thin film layers and metal thin film layers are alternately laminated (see, for example, Patent Documents 1 and 2). In a multilayer thin film in which transparent thin film layers and metal thin film layers are alternately laminated, a metal thin film layer such as silver exhibits conductivity and optical characteristics, and the transparent thin film layer prevents reflection of light by a metal in a specific wavelength region. Therefore, all of conductivity, near-infrared cutability, and visible light transmittance are excellent.
Japanese Patent Publication No. 8-32436 JP 2000-031687 A

However, since the thing of patent document 1 does not have the performance which shields the strong electromagnetic waves emitted from a plasma display and near infrared rays, and the use as a display filter is not assumed, it is anti-reflective. The sex was low. Therefore, the reflection of lighting etc. became a problem.
Patent Document 2 discloses a laminate used for display applications, but this laminate is not supposed to be attached to the outermost surface, and a separate antireflection layer is additionally provided on the laminate. It is done. Therefore, the reflected light and cost of the laminate itself have become a problem.
The present invention has been made in view of the above circumstances, and has a transparent laminate, a display filter, and a plasma display that are excellent in transparency, electromagnetic shielding properties, and infrared cut properties, and also excellent in antireflection properties. The purpose is to provide.

The transparent laminate, display filter, and plasma display of the present invention are as shown in the following (1) to (14).
(1) a transparent substrate;
A transparent laminate having transparent thin film layers and metal thin film layers alternately, and having a shield layer in which the number of metal thin film layers is n and the number of transparent thin film layers is n + 1 (where n is an integer of 1 or more). There,
The surface resistance value of the shield layer surface is 4Ω or less, the visible light transmittance is 40% or more, the luminous reflectance is 2% or less, and the light transmittance in a wavelength region longer than 800 nm is 20% or less. Transparent laminate.
Here, “the transparent thin film layer and the metal thin film layer are alternately provided” does not necessarily mean that the transparent thin film layer and the metal thin film layer are adjacent to each other. Another layer may be provided between them.
(2) The transparent thin film according to (1), wherein the metal thin film layer has a refractive index of light having a wavelength of 550 nm of 0.2 or less and an extinction coefficient of 5.0 or less.
(3) The number n of the metal thin film layers is 1,
The optical film thickness in the light with a wavelength of 550 nm of the transparent thin film layer closer to the transparent substrate is
When the refractive index of the transparent thin film layer> the refractive index of the transparent substrate, 45 to 90 nm,
In the case of the refractive index of the transparent thin film layer <the refractive index of the transparent substrate, 140 to 270 nm
In the range of
The optical film thickness of the transparent thin film layer far from the transparent substrate is in the range of 45 to 90 nm,
The transparent laminated body according to (1) or (2), wherein the physical film thickness of the metal thin film layer is in the range of 5 to 20 nm.
(4) The number n of the metal thin film layers is 2 or more,
The optical film thickness in the light of the wavelength of 550 nm of the transparent thin film layer closest to the transparent substrate is
When the refractive index of the transparent thin film layer> the refractive index of the transparent substrate, 45 to 90 nm,
In the case of the refractive index of the transparent thin film layer <the refractive index of the transparent substrate, 140 to 270 nm
In the range of
The optical film thickness of the transparent thin film layer farthest from the transparent substrate is in the range of 45 to 90 nm,
The optical film thickness of each other transparent thin film layer is in the range of 95 to 180 nm,
The transparent layered product according to (1) or (2), wherein the physical film thickness of each metal thin film layer is in the range of 5 to 20 nm and the total physical film thickness of the metal thin film layers is in the range of 20 to 70 nm. .
(5) The transparent laminate according to any one of (1) to (4), wherein a protective layer is provided in the shield layer.
(6) The transparent laminate according to any one of (1) to (5), wherein an antifouling layer is provided on the surface.
(7) The transparent laminate according to (6), wherein a protective layer is provided between the antifouling layer and the shield layer.
(8) The transparent laminate according to any one of (1) to (7), wherein the transparent substrate does not contain 10 ppm or more of an alkali component.
(9) The transparent laminate according to any one of (1) to (8), wherein the transparent substrate does not contain 10 ppm or more of a halogen component.
(10) The transparent laminate according to any one of (1) to (9), wherein an adhesive layer is provided on one side of the transparent substrate.
(11) The transparent laminate according to (10), wherein the adhesive layer does not contain 10 ppm or more of an alkali component.
(12) The transparent laminate according to (10) or (11), wherein the adhesive layer does not contain 10 ppm or more of a halogen component.
(13) A display filter comprising the transparent laminate according to any one of (1) to (12).
(14) A plasma display comprising the transparent laminate according to any one of (1) to (12) or the display filter according to (13).

The transparent laminate of the present invention and the display filter of the present invention are excellent in transparency, electromagnetic wave shielding properties, and infrared cut properties, and are also excellent in antireflection properties. Therefore, when the transparent laminate of the present invention and the display filter of the present invention are used, it is not necessary to separately provide an antireflection layer.
In addition, since the plasma display of the present invention does not need to be provided with an antireflection layer, the cost can be saved.

An embodiment of the present invention will be described.
In FIG. 1, sectional drawing of the transparent laminated body of this embodiment is shown. The transparent laminate 1 includes a transparent substrate 10, a hard coat layer 20 in contact with one surface of the transparent substrate 10, an inorganic layer 30 in contact with the hard coat layer 20, a shield layer 40 in contact with the inorganic layer 30, The antifouling layer 50 in contact with the shield layer 40 and the adhesive layer 60 in contact with the other surface of the transparent substrate 10 are provided. Further, the shield layer 40 includes a transparent thin film layer 41a, a protective layer 42a, a metal thin film layer 43a, a transparent thin film layer 41b, a metal thin film layer 43b, a transparent thin film layer 41c, and a metal thin film from the transparent substrate 10 side. A layer 43c, a transparent thin film layer 41d, a metal thin film layer 43d, a protective layer 42b, and a transparent thin film layer 41e are provided.

Examples of the transparent base material 10 include inorganic compound moldings such as glass and quartz, and transparent organic polymer moldings. Considering application to the surface of the plasma display, they are light and difficult to break and have flexibility. The organic polymer molded product is preferred. In addition, as long as the surface is smooth, the molded product here may be a plate (sheet) shape or a film shape.
The organic polymer molding may be transparent in the visible wavelength region, and examples of the material thereof include polyethylene terephthalate (PET), polystyrene, polyethylene naphthalate, polyarylate, polyetheretherketone, polycarbonate, polypropylene, and polyimide. Can be mentioned.
Further, the organic polymer constituting the organic polymer molded product may contain a known additive such as an ultraviolet absorber, a plasticizer, a lubricant, a colorant, an antioxidant, a flame retardant and the like.
However, from the viewpoint of preventing deterioration of the metal thin film layer, the transparent substrate 10 may not contain 10 ppm or more of each of alkalis such as sodium, potassium, calcium and magnesium and halogens such as fluorine, chlorine, bromine and iodine. It is preferable that 5 ppm or more is not included, and it is particularly preferable that it is not included at all. Transparent substrates with low alkali content and low halogen content are commercially available.

Among organic polymer molded products, it is preferable to use a highly flexible organic polymer film. When the organic polymer film is used, the transparent conductive layer can be continuously formed by a roll-to-roll method, so that the production efficiency is high, and a long and large transparent laminate can be easily produced. And the transparent laminated body obtained also becomes a film form, and when it affixes on the glass of a display, the scattering prevention effect at the time of glass breakage is exhibited.
The thickness of the organic polymer film is usually 10 to 250 μm. If the thickness of the film is less than 10 μm, the mechanical strength as a substrate is insufficient, and if the thickness exceeds 250 μm, the flexibility is insufficient, so that the film is not suitable for being wound with a roll.

It is preferable that the transparent substrate 10 has been subjected to etching treatment such as sputtering treatment, corona treatment, flame treatment, ultraviolet irradiation, electron beam irradiation, and undercoating treatment on the surface in advance. If the said process is given to the surface of the transparent base material 10, the adhesiveness with respect to another adjacent layer can be improved.
Moreover, if necessary, the transparent substrate 10 may be subjected to a dustproof treatment such as solvent cleaning or ultrasonic cleaning on the surface.

The hard coat layer 20 improves the hardness of the surface of the transparent base material 10, prevents scratches caused by scratching with a load such as a pencil, and suppresses the occurrence of cracks in the shield layer 40 due to the bending of the transparent base material 10, and is transparent. It is a layer that increases the mechanical strength of the laminate 1.
The hard coat layer 20 is made of a polymer mainly composed of a polyfunctional monomer containing two or more (meth) acryloyloxy groups in one molecule. Examples of the polyfunctional monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, tri Ethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, 3-methylpentanediol di (meth) acrylate, diethylene glycol bis β- (meth) acryloyloxypropionate, Trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (2-hydroxyethyl) isocyanate di (meth) acrylate, pentaerythritol tetra (meth) acrylate, 2,3-bis (meth) acryloyloxyethyloxymethyl [2.2.1] heptane, poly 1,2-butadiene di (Meth) acrylate, 1,2-bis (meth) acryloyloxymethylhexane, nonaethylene glycol di (meth) acrylate, tetradecane ethylene glycol di (meth) acrylate, 10-decanediol (meth) acrylate, 3,8-bis (Meth) acryloyloxymethyltricyclo [5.2.10] decane, hydrogenated bisphenol A di (meth) acrylate, 2,2-bis (4- (meth) acryloyloxydiethoxyphenyl) propane, 1,4- Bis ((meth) acryloyl Kishimechiru) cyclohexane, hydroxypivalic acid ester neopentyl glycol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, epoxy-modified bisphenol A di (meth) acrylate. In particular, acrylic resins such as acrylic acid esters, acrylamides, methacrylic acid esters, and methacrylamides that are ultraviolet curable, organic silicon resins, thermosetting polysiloxane resins, and the like are suitable. The said polyfunctional monomer may use only 1 type and may use 2 or more types together. If necessary, a monofunctional monomer may be copolymerized.
Further, the hard coat layer 20 preferably has the same or approximate refractive index as that of the transparent substrate 10 in order to ensure the transparency of the transparent laminate 1.
If the thickness of the hard coat layer 20 is in the range of 3 to 20 μm, sufficient mechanical strength is exhibited, but it is preferably in the range of 5 to 15 μm from the viewpoint of transparency, coating accuracy, and handleability.

  In the hard coat layer 20, inorganic fine particles or organic fine particles having an average particle diameter of 0.01 to 3 μm may be mixed and dispersed. By mixing these fine particles in the hard coat layer 20 and making the surface uneven, a light diffusing treatment called antiglare can be performed. These fine particles are not particularly limited as long as they are transparent, but a low refractive index material is preferable, and silicon oxide and magnesium fluoride are particularly preferable in terms of excellent stability, heat resistance and the like. Among these, hollow silicon oxide is more preferable because of its particularly low refractive index.

The hard coat layer 20 is preferably subjected to a surface treatment. By performing the surface treatment, adhesion with other adjacent layers can be improved.
Examples of the surface treatment of the hard coat layer 20 include a high-frequency discharge plasma method, an electron beam method, an ion beam method, a vapor deposition method, a sputtering method, an alkali treatment method, an acid treatment method, a corona treatment method, and an atmospheric pressure glow discharge plasma method. Is mentioned. Among these, alkali treatment is preferable.
Examples of the alkaline aqueous solution used in the alkali treatment method include aqueous solutions such as sodium hydroxide and potassium hydroxide, and alkaline aqueous solutions obtained by adding various organic solvents such as alcohol to these. As the conditions for the alkali treatment, for example, when an aqueous sodium hydroxide solution is used, it is preferably used as an aqueous solution having a concentration of 0.1 to 10N, preferably 1 to 2N. Moreover, the temperature of aqueous alkali solution is 0-100 degreeC, Preferably it is 20-80 degreeC. The alkali treatment time is 0.01 to 10 hours, preferably 0.1 to 1 hour. However, when such alkali cleaning is performed, it is necessary to perform sufficient cleaning so that no alkali component remains.

The inorganic layer 30 is a layer for enhancing the adhesion between the hard coat layer 20 and the shield layer 40. Examples of the material of the inorganic layer 30 include silicon, nickel, chromium, gold, silver, platinum, zinc, zirconium, titanium, tungsten, tin, and palladium, or alloys, oxides, and the like made of two or more of these materials. Is mentioned. The thickness of the inorganic layer 30 should just be a thickness which does not impair transparency, Preferably it is about 0.2 nm-10 nm. If the thickness of the inorganic layer 30 is too thin, the adhesion is not sufficiently improved, and if it is too thick, the transparency is impaired.
In addition, when the transparent thin film layer 41a of the shield layer 40 in contact with the inorganic layer 30 is an oxide, part or all of the metal of the inorganic layer 30 may be transformed into a metal oxide. There is no problem in effect.

The transparent thin film layers 41a to 41e in the shield layer 40 are layers having transparency with respect to visible light, and are layers that prevent light reflection in the visible region in the metal thin film layer due to a difference in refractive index with the metal thin film layer. .
As a material for forming the transparent thin film layers 41a to 41e, a material having a high refractive index in order to reduce the thickness thereof, specifically, a material having a refractive index with respect to visible light of 1.6 or more, preferably 1.7 or more. Used. Such materials include indium, titanium, zirconium, bismuth, tin, zinc, antimony, tantalum, cerium, neodymium, lanthanum, thorium, magnesium, gallium and other oxides, or mixtures of these oxides, zinc sulfide. Etc. These oxides or sulfides can be used as long as they do not significantly change the optical characteristics even if the stoichiometric composition of metal and oxygen or sulfur is different. However, when using sulfides, it is necessary to consider the influence of sulfur on the silver alloy. An organic compound can also be used if the refractive index is within the above range. In that case, metal fine particles or the like may be added to increase the refractive index.
Among these, indium oxide, a mixture of indium oxide and tin oxide (ITO), and a mixture of indium oxide and cerium oxide as a main component (ICO) have high transparency and a high refractive index, and sputtering by direct current discharge ( DC sputtering) film formation is possible, the film formation rate is high, and the adhesion with the metal thin film layer is good, which is preferable. Further, by using an oxide semiconductor thin film having relatively high conductivity such as ITO, absorption of electromagnetic waves can be increased.
For the formation of the transparent thin film layers 41a to 41e, a conventionally known method such as sputtering, ion plating, ion beam assist, vacuum deposition, or wet coating can be employed.

  The metal thin film layers 43a to 43d in the shield layer 40 are thin films made of metal, but preferably have a refractive index of light having a wavelength of 550 nm of 0.2 or less and an extinction coefficient of 5.0 or less. If the refractive index of light having a wavelength of 550 nm is 0.2 or less, the transparency is higher, and if the extinction coefficient is 5.0 or less, high transparency can be ensured even when a multilayer structure is used. Moreover, it is preferable that the metal atoms in the metal thin film layers 43a to 43d have a continuous structure rather than an island structure from the viewpoint of conductivity and the like.

Examples of a material having such a refractive index and extinction coefficient include silver or an alloy containing silver. Silver is excellent in electroconductivity, infrared reflectivity, and visible light transmittance when multilayered. In addition, an alloy containing silver increases the chemical stability and physical stability of silver, and can prevent deterioration and aggregation due to environmental pollutants, water, oxygen, alkali, halogen, sulfur, heat, light, and the like.
Examples of metals other than silver in silver alloys include gold, platinum, palladium, copper, indium, tin, bismuth and other precious metals that are stable to the environment, and metals such as rare earth that move near the silver interface and form a protective layer. preferable. Two or more kinds of these metals may be contained. Among these, substitutional elements that do not destroy the face-centered cubic lattice structure, which is a crystal structure of silver, and elements that move and precipitate at the interface after forming the metal thin film layer to form a protective film for the metal thin film layer are preferable.
The silver content in the silver-containing alloy is preferably 0.3% by mass or more and less than 30% by mass, which is in a range not largely different from the conductivity and optical characteristics of the silver thin film.

The composition of each metal thin film layer 43a-43d does not need to be the same, for example, content of silver in metal thin film layer 43a-43d and the kind of metal used besides silver may be changed.
For the formation of the metal thin film layers 43a to 43d, any of conventionally known methods such as sputtering, ion plating, vacuum deposition, plating, etc. can be employed.
In addition, when the transparent thin film layer adjacent to the metal thin film layers 43a-43d is an oxide, a part of metal of the metal thin film layers 43a-43d may change into a metal oxide. However, since such metal oxide regions in the metal thin film layers 43a to 43d are very thin, there is no problem in optical design and film formation.

In the shield layer 40, the thicknesses of the transparent thin film layers 41a to 41e and the metal thin film layers 43a to 43d are specified as follows. The optical film thickness described below is a thickness represented by (refractive index) × (physical film thickness).
The optical film thickness in the light of wavelength 550 nm of the transparent thin film layer 41a closest to the transparent substrate 10 is
If the refractive index of the transparent thin film layer> the refractive index of the transparent substrate,
(Visible light central wavelength 550 nm / 8) about ± 30%, that is, in the range of 45 to 90 nm,
If the refractive index of the transparent thin film layer is smaller than the refractive index of the transparent substrate,
(Center wavelength of visible light 550 nm × 3/8) is about ± 30%, that is, 140 to 270 nm. In addition, even when 550 nm / 2 (275 nm) is added to the above range, the same effect as when the above range is obtained may be exhibited.
Moreover, the optical film thickness of the transparent thin film layer 41e farthest from the transparent substrate 10 is in the range of (visible light center wavelength 550 nm / 8) ± 30%, that is, 45 to 90 nm, and other transparent thin film layers. The optical film thicknesses of 41b, 41c, and 41d are about (center wavelength of visible light 550 nm / 4) ± 30%, that is, in the range of 95 to 180 nm.
Furthermore, the physical film thickness of each metal thin film layer 43a-43d is 5-20 nm, and the total physical film thickness of a metal thin film layer exists in the range of 20-70 nm, Preferably it is 35-55 nm.
When the metal thin film layer and the transparent thin film layer are in the above ranges, the anti-reflection property is exhibited, and the electromagnetic wave shielding property, the infrared ray cutting property, and the transparency can be ensured.

Examples of the material of the protective layers 42a and 42b include metal materials such as silicon, chromium, gold, antimony, copper, platinum, titanium, palladium, and bismuth, oxides such as silicon oxide and titanium oxide, silicon nitride, and titanium nitride. And nitrides thereof and combinations thereof.
The thickness of the protective layers 42a and 42b may be a thickness that does not impair the transparency, and is preferably about 0.2 nm to 10 nm.
By providing such protective layers 42a and 42b, the penetration of oxygen, water, alkali, halogen, etc. into the interface between the transparent thin film layer and the metal thin film layer can be blocked to suppress the deterioration of the metal thin film layer. Further, the protective layers 42a and 42b can suppress the deterioration of the metal thin film layer when the transparent thin film layer is formed.

The antifouling layer 50 is a layer having water repellency, oil repellency, and low friction properties, and is a layer provided on the surface of the transparent laminate 1. As a material of the antifouling layer 50, for example, silicon oxide, fluorine-containing silicon compound, fluoroalkylsilazane, fluoroalkylsilane, fluorine-containing silane compound, perfluoropolyether group-containing silane coupling agent, or the like is used.
Tempered glass is attached to the surface of the plasma display in order to improve antifouling properties and scratch resistance. However, since it causes reflection, it has not been attached in recent years. In the case where no tempered glass is attached, a transparent laminate having the antifouling layer 50 as in this embodiment is suitable.

The material of the adhesive layer 60 has a refractive index of light having a wavelength of 500 to 600 nm of about 1.45 to 1.7, an extinction coefficient of about 0, and has adhesiveness. Examples of such materials include acrylic adhesives, silicon adhesives, urethane adhesives, polyvinyl butyral adhesives (PVB), ethylene-vinyl acetate adhesives (EVA), polyvinyl ethers, and saturated amorphous polyesters. And melamine resin.
Alkalis such as sodium, potassium, calcium, and magnesium contained in the adhesive layer 60 and halogens such as fluorine, chlorine, bromine, and iodine can cause deterioration of the metal thin film layer. Therefore, the pressure-sensitive adhesive layer 60 preferably does not contain 10 ppm or more of alkali and halogen, more preferably does not contain 5 ppm or more, and particularly preferably does not contain at all.

In the transparent laminate 1 having the above-described configuration, the surface resistance value of the shield layer surface is 4Ω or less, preferably 2Ω or less, more preferably 1.5Ω or less. If it has such high electroconductivity, sufficient electromagnetic wave shielding property can be improved.
Here, the surface of the shield layer 40 is a surface of the shield layer 40 in contact with the inorganic layer 30 or the antifouling layer 50 in this embodiment, and this surface is sometimes referred to as a conductive surface. The sheet resistance value is a value measured by a method based on JIS K7194 using a four-terminal four-probe resistivity meter Loresta GP (manufactured by Dia Instruments).

The visible light transmittance of the transparent laminate 1 is 40% or more, preferably 60% or more, more preferably 70% or more. When the visible light transmittance is 40% or more, the sharpness of the image is not lowered when the transparent laminate 1 is attached to the display.
Further, the luminous reflectance of the transparent laminate 1 is 2% or less, preferably 1.5% or less, more preferably 1.0% or less. With such a reflectance, it can be said that the antireflection property is sufficiently high. Therefore, it is possible to prevent the display screen from being difficult to see due to the reflection of a lighting fixture or the like on the display without providing an antireflection layer separately.
Note that the visible light transmittance and luminous reflectance in the present invention are values calculated according to JIS R-3106 from the wavelength dependency of transmittance and reflectance.

The transparent laminate 1 has a light transmittance of 20% or less in a region having a wavelength longer than 800 nm. In this way, the light transmittance in the wavelength region longer than 800 nm is 20% or less, so that even if the plasma display emits near-infrared light over the entire wavelength region of 800 to 1000 nm, it is cut to such an extent that it does not cause a practical problem. it can. Here, the light transmittance in the wavelength region longer than 800 nm is a value measured in the wavelength range of 800 to 1000 nm using a spectrophotometer U-4000 (manufactured by Hitachi High-Technology). Except for the wavelength range, it conforms to JIS R1625.
In order to obtain the light transmittance, the transparent laminate 1 may contain a near infrared absorbing dye, and when the transparent laminate 1 contains a near infrared absorbing dye, the near infrared cutting property of the shield layer 40. May be lower than the required performance. However, when the content of the near-infrared absorbing dye is too large, the visible light transmittance is reduced.
In addition, as a method of cutting near infrared rays, a method using metal free electron reflection is also conceivable, but if the metal thin film layer is thickened, the visible light transmittance is lowered, and if it is thinned, the reflection of near infrared rays is weakened. Not practical.

The transparent laminate described above has a shield layer in which metal thin film layers and transparent thin film layers are alternately provided, the surface resistance value of the shield layer surface is 4Ω or less, high electrical conductivity, and electromagnetic waves. Since it can be absorbed sufficiently, it has high electromagnetic shielding properties. Moreover, since near infrared rays are absorbed over the whole area even if it does not use a near-infrared absorption pigment | dye by a shield layer, near-infrared cut property can be ensured. Furthermore, despite having high electromagnetic shielding properties and near-infrared cutting properties, the total film thickness of each metal thin film layer and metal thin film layer is thin, and no near-infrared absorbing dye is used. The transmittance is 40% or more, and the transparency is high.
In addition, in the shield layer, the transparent thin film layer and the metal thin film layer have specific thicknesses, so that they exhibit not only electromagnetic wave shielding properties and near infrared ray cutting properties but also antireflection properties.

Note that the present invention is not limited to the above-described embodiments. In the embodiment described above, the hard coat layer, the inorganic layer, and the adhesive layer are provided, but these are not essential.
In the embodiment described above, the number n of metal thin film layers is 4 (the number of transparent thin film layers is 5), but may be other than 4.
However, the number n of the metal thin film layers is preferably 1 to 8, and more preferably 3 to 5. If n is 2 or less, it will be difficult to simultaneously secure near-infrared cut properties, antireflection properties, and electromagnetic wave shielding properties. If n is 6 or more, there will be a problem of limitations on production equipment and productivity. Visible light transmittance may be lowered.
Since the transparent thin film layer is always one more than the metal thin film layer, and the transparent thin film layer and the metal thin film layer are alternately provided, in other embodiments, the transparent thin film layer is always positioned on the surface layer on both sides of the shield layer. To do.

In FIG. 2, the number n of the metal thin film layers is 1, and the transparent laminated body having the simplest configuration in which the hard coat layer, the inorganic layer, the antifouling layer, and the adhesive layer are not provided. Indicates. This transparent laminated body 2 has the transparent base material 10 and the shield layer 40, and the shield layer 40 consists of the transparent thin film layer 45a, the metal thin film layer 46, and the transparent thin film layer 45b.
In this transparent laminated body 2, the optical film thickness in the light with a wavelength of 550 nm of the transparent thin film layer 45a closer to the transparent substrate 10 is:
If the refractive index of the transparent thin film layer> the refractive index of the transparent substrate,
(Visible light central wavelength 550 nm / 8) about ± 30%, that is, in the range of 45 to 90 nm,
If the refractive index of the transparent thin film layer is smaller than the refractive index of the transparent substrate,
(Center wavelength of visible light 550 nm × 3/8) is about ± 30%, that is, 140 to 270 nm. In addition, even when 550 nm / 2 (275 nm) is added to the above range, the same effect as when the above range is obtained may be exhibited.
The optical film thickness of the transparent thin film layer 45b far from the transparent substrate 10 is in the range of about 30% (center wavelength of visible light 550 nm / 8) ± 30%, that is, 45 to 90 nm. The physical film thickness is in the range of 5-20 nm.

In the embodiment described above, as shown in FIG. 1, the transparent thin film layer 41 e farthest from the transparent substrate 10 and the metal thin film between the transparent thin film layer 41 a and the metal thin film layer 43 a closest to the transparent substrate 10. The protective layers 42a and 42b are provided between the layer 43d, but in the present invention, the protective layers 42a and 42b may be provided only in either one or between all the transparent thin film layers and the metal thin film layers. It may be.
Furthermore, a protective layer may be provided between the antifouling layer and the shield layer. In this case, the protective layer protects the entire shield layer.

The display filter of the present invention is obtained by providing another layer on the transparent laminate. Examples of the other layers include an antiglare layer that ensures antiglare properties and an anti-Newton ring layer that suppresses the occurrence of Newton rings. These other layers can be formed by a known method.
Moreover, the plasma display of this invention comprises the said transparent laminated body or the said filter for a display. By providing the transparent laminate or the display filter in the plasma display, it is possible to provide an electromagnetic wave shielding property and an infrared ray cutting property, as well as an antireflection property. Down is possible.

On the polyethylene terephthalate substrate (transparent substrate), a hard coat layer made of a polymer of triethylene glycol (meth) acrylate containing no alkali component or halogen component is provided, and an ITO layer is formed thereon by DC sputtering. (Transparent thin film layer): 39.5 nm, Silver alloy layer containing silver and gold (metal thin film layer): 7.2 nm, ITO layer (refractive index 2.1): 76.8 nm, Silver alloy layer: 9. 3 nm, ITO layer: 72.8 nm, silver alloy layer: 10.2 nm, ITO layer: 75.8 nm, silver alloy layer: 11.8 nm, ITO layer: 37.6 nm (each film thickness is a physical film thickness) A film was formed, and an antifouling layer made of fluoroalkylsilazane was provided on the outermost surface to obtain a transparent laminate.
The surface resistance of this transparent laminate, the transmittance of visible light (wavelength 500 nm), the luminous reflectance, and the transmittance in the near infrared (wavelength 850 nm) were measured. The visible light transmittance was 75.8%, and the luminous reflection. The rate was 0.68%, the near infrared transmittance was 5%, and it was confirmed that all of the antireflection performance, the visible light transparency (transparency), and the near infrared cutability were satisfied. It was also confirmed that the sheet resistance value was 1.0Ω, and the shielding effect at 1 GHz was 40 dB or more and sufficient electromagnetic shielding properties. Furthermore, it was confirmed that the environment-resistant performance had sufficient resistance when it was allowed to stand for 500 hours or more in a constant temperature and humidity soda having a temperature of 40 ° C. and a relative humidity of 90%.

  The transparent laminate of the present invention is not limited to a plasma display, and can be suitably used for those requiring transparency, antireflection properties, electromagnetic wave shielding properties, and infrared cut properties.

It is sectional drawing which shows the transparent laminated body of one example of embodiment which concerns on this invention. It is sectional drawing which shows the transparent laminated body of the other embodiment example which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Transparent laminated body 10 Transparent base material 40 Shield layer 41a-41e, 45a, 45b Transparent thin film layer 42a, 42b Protective layer 43a-43d, 46 Metal thin film layer 50 Antifouling layer 60 Adhesion layer

Claims (14)

A transparent substrate;
A transparent laminate having transparent thin film layers and metal thin film layers alternately, and having a shield layer in which the number of metal thin film layers is n and the number of transparent thin film layers is n + 1 (where n is an integer of 1 or more). There,
The surface resistance value of the shield layer surface is 4Ω or less, the visible light transmittance is 40% or more, the luminous reflectance is 2% or less, and the light transmittance in a wavelength region longer than 800 nm is 20% or less. Transparent laminate.   2. The transparent laminate according to claim 1, wherein the metal thin film layer has a refractive index of light having a wavelength of 550 nm of 0.2 or less and an extinction coefficient of 5.0 or less. The number n of metal thin film layers is 1,
The optical film thickness in the light with a wavelength of 550 nm of the transparent thin film layer closer to the transparent substrate is
When the refractive index of the transparent thin film layer> the refractive index of the transparent substrate, 45 to 90 nm,
In the case of the refractive index of the transparent thin film layer <the refractive index of the transparent substrate, 140 to 270 nm
In the range of
The optical film thickness of the transparent thin film layer far from the transparent substrate is in the range of 45 to 90 nm,
The transparent laminated body according to claim 1 or 2, wherein the physical film thickness of the metal thin film layer is in the range of 5 to 20 nm. The number n of metal thin film layers is 2 or more,
The optical film thickness in the light of the wavelength of 550 nm of the transparent thin film layer closest to the transparent substrate is
When the refractive index of the transparent thin film layer> the refractive index of the transparent substrate, 45 to 90 nm,
In the case of the refractive index of the transparent thin film layer <the refractive index of the transparent substrate, 140 to 270 nm
In the range of
The optical film thickness of the transparent thin film layer farthest from the transparent substrate is in the range of 45 to 90 nm,
The optical film thickness of each other transparent thin film layer is in the range of 95 to 180 nm,
The transparent laminated body according to claim 1 or 2, wherein the physical film thickness of each metal thin film layer is in the range of 5 to 20 nm, and the total physical film thickness of the metal thin film layers is in the range of 20 to 70 nm.   The transparent laminate according to claim 1, wherein a protective layer is provided in the shield layer.   The transparent laminate according to any one of claims 1 to 5, wherein an antifouling layer is provided on the surface.   The transparent laminate according to claim 6, wherein a protective layer is provided between the antifouling layer and the shield layer.   The transparent substrate according to any one of claims 1 to 7, wherein the transparent substrate does not contain 10 ppm or more of an alkali component.   The transparent laminate according to any one of claims 1 to 8, wherein the transparent substrate does not contain 10 ppm or more of a halogen component.   The transparent laminate according to any one of claims 1 to 9, wherein an adhesive layer is provided on one side of the transparent substrate.   The transparent laminate according to claim 10, wherein the adhesive layer does not contain 10 ppm or more of an alkali component.   The transparent laminate according to claim 10 or 11, wherein the adhesive layer does not contain 10 ppm or more of a halogen component.   A display filter comprising the transparent laminate according to claim 1. A plasma display comprising the transparent laminate according to any one of claims 1 to 12 or the display filter according to claim 13.

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