JP2008036952A - Electroconductive laminate and protective plate for plasma display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive laminate having a wide transparency/reflection band and excellent electroconductivity (electromagnetic wave shielding ability), visible light transparency and near-infrared shielding ability, and a protective plate for a plasma display. <P>SOLUTION: The electroconductive laminate 10 includes a substrate 11 and an electroconductive film 12 formed on the substrate 11. The electroconductive film 12 has a multilayer structure in which oxide layers 12a and metal layers 12b are laminated alternatively in (2n+1) layers [n is an integer of not less than 1] in total, starting from the side of the substrate 11. The oxide layers 12a contain indium and tungsten as the oxides. The metal layers 12b contain silver or a silver alloy as the primary component. The protective plate for plasma displays is constituted of a support base, the electroconductive laminate 10 placed on the support base and electrodes electrically connected with the electroconductive film of the electroconductive laminate 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a plasma display having an electromagnetic wave shielding ability which is installed on the observer side of a PDP to protect a conductive laminate and a plasma display panel (hereinafter abbreviated as PDP) body and shields electromagnetic waves generated from the PDP. It relates to a protective plate.

  The conductive laminate having transparency is used as a transparent electrode such as a liquid crystal display element, an automobile windshield, a heat mirror, an electromagnetic wave shielding window glass, and the like. Further, the conductive laminate is used as a filter that shields electromagnetic waves generated from the PDP. For example, on the viewer side of the PDP, a conductive laminate in which a total of (2n + 1) layers of oxide layers having a high refractive index and metal layers made of silver or a silver alloy are alternately laminated on the substrate, A protective plate for plasma display in which a conductive laminate is further provided on a support substrate is disposed.

As the conductive laminate, for example, the following are known.
(1) A conductive laminate in which the oxide layer is a layer made of a mixture of indium oxide and tin oxide (Patent Document 1).
(2) A conductive laminate in which the oxide layer is a layer containing zinc oxide and titanium oxide as main components (Patent Document 2).

The conductive laminate is required to have a high transmittance over the entire visible light region and a low reflectance, that is, a wide transmission / reflection band, and a high shielding property in the near infrared region. .
However, although the conductive laminate of (1) has a wide reflection band, it has a problem that the transmittance on the low wavelength side is low and the transmission band is narrow.
Although the conductive laminate of (2) has a wide transmission band, it has a problem that the reflection band is slightly narrower than that of the conductive laminate of (1).
Japanese Patent Laid-Open No. 10-217380 JP 2006-186309 A

  It is an object of the present invention to provide a conductive laminate and a plasma display protective plate having a wide transmission / reflection band and excellent conductivity (electromagnetic wave shielding property), visible light transmittance, and near-infrared shielding property. To do.

The conductive laminate of the present invention is a conductive laminate having a substrate and a conductive film formed on the substrate, and the conductive film is alternately measured from the substrate side by an oxide layer and a metal layer. (2n + 1) layers [where n is an integer of 1 or more. ] A laminated multilayer structure, wherein the oxide layer is a layer containing indium and tungsten as oxides, and the metal layer is a layer containing silver or a silver alloy as a main component.
The oxide layer is preferably a layer further containing one or more selected from the group consisting of zinc and silicon as an oxide.
The atomic ratio (W / In) of tungsten and indium in the oxide layer is preferably 0.001 to 0.035.
The number of metal layers is preferably 2-8.
The metal layer is preferably a layer made of pure silver or a layer made of a silver alloy containing at least one selected from gold, palladium and bismuth.

The protective plate for plasma display of the present invention has a support base, the conductive laminate of the present invention provided on the support base, and an electrode that is in electrical contact with the conductive film of the conductive laminate. It is characterized by that.
The protective plate for plasma display of the present invention preferably further has a conductive mesh film.

The conductive laminate of the present invention has a wide transmission / reflection band, and is excellent in conductivity (electromagnetic wave shielding property), visible light transmittance, and near-infrared shielding property.
The protective plate for plasma display of the present invention is excellent in electromagnetic wave shielding ability, has a wide transmission / reflection band, has high visible light transmittance, and has excellent near-infrared shielding properties.

<Conductive laminate>
FIG. 1 is a cross-sectional view showing an example of the conductive laminate of the present invention. The conductive laminate 10 has a base 11 and a conductive film 12.

(Substrate)
Examples of the substrate 11 include substrates that transmit visible light, such as glass plates, plastic plates, and plastic films.
As the glass, tempered glass such as air-cooled tempered glass and chemically tempered glass may be used.
Examples of the plastic include polyethylene terephthalate, polycarbonate, triacetyl cellulose, polyether sulfone, and polymethyl methacrylate.

(Conductive film)
The conductive film 12 has a total of (2n + 1) layers of oxide layers 12a and metal layers 12b alternately from the substrate 11 side [where n is an integer of 1 or more. It is a laminated multilayer structure. n is preferably from 2 to 8, and more preferably from 2 to 6.

(Oxide layer)
The oxide layer 12a is a layer containing indium and tungsten as oxides. In the oxide layer 12a, indium and tungsten are considered to exist in a form in which indium oxide, tungsten oxide, and a composite oxide thereof are mixed.

The total of indium and tungsten is preferably 90 atomic percent or more, and more preferably 95 mass percent or more in the total metal (including semimetals such as silicon) (100 atomic percent) contained in the oxide layer 12a. By setting the total of indium and tungsten within this range, the refractive index of the oxide layer 12a becomes sufficiently high, and the transmission / reflection band of the conductive film 12 becomes sufficiently wide.
The atomic ratio of each element in the oxide layer 12a is measured by ESCA (X-ray photoelectron spectroscopy) or Rutherford backscattering spectroscopy.

  The atomic ratio (W / In) between tungsten and indium in the oxide layer 12a is preferably 0.001 to 0.035, more preferably 0.002 to 0.02, and further preferably 0.003 to 0.015. . By setting the atomic ratio of tungsten and indium within this range, the oxide layer 12a tends to be amorphous. If the oxide layer 12a is amorphous, light scattering is suppressed, and the visible light transmittance of the conductive film 12 is increased.

  The oxide layer 12a may contain an oxide other than indium and tungsten. Examples of other metals include zinc and silicon. By including these metal oxides, the oxide layer 12a tends to be amorphous. If the oxide layer 12a is amorphous, light scattering is suppressed, and the visible light transmittance of the conductive film 12 is increased. In particular, zinc is preferable from the viewpoint of discharge stability during film formation.

The atomic ratio (Zn / In) between zinc and indium in the oxide layer 12a is preferably 0.001 to 0.035, and more preferably 0.003 to 0.03. By setting the atomic ratio of zinc and indium within this range, the oxide layer 12a is likely to be amorphous, and high transmittance on the short wavelength side can be obtained.
The content ratio of oxygen atoms in the oxide layer 12a is preferably 50 to 70 atomic% in the oxide layer 12a, and more preferably 55 to 65 atomic%.

The physical film thickness (hereinafter simply referred to as film thickness) of the oxide layer 12a is preferably 20 to 60 nm for the oxide layer 12a closest to the base 11 and the oxide layer 12a farthest from the base 11, and preferably 30 to 60 nm. 50 nm is more preferable, and about the other oxide layer 12a, 40-120 nm is preferable and 40-100 nm is more preferable.
The thicknesses of the respective oxide layers 12a in the conductive laminate of the present invention may all be the same, layers having the same thickness and layers having different thicknesses may be mixed, or each layer may be different. Good.

(Metal layer)
The metal layer 12b is a layer containing silver or a silver alloy as a main component. Since the metal layer 12b is formed of silver or a silver alloy, the resistance value of the conductive film 12 can be lowered.
The metal layer 12b is preferably a layer made of pure silver from the viewpoint of reducing the resistance value of the conductive film 12. Pure silver means that 99.9% by mass or more of silver is contained in the metal layer 12b (100% by mass).

  The metal layer 12b is preferably a layer made of a silver alloy containing at least one selected from gold, palladium, and bismuth from the viewpoint of suppressing diffusion of silver and consequently improving moisture resistance. The total of gold, palladium and bismuth is preferably 0.2 to 1.5% by mass in the metal layer 12b (100% by mass) so that the specific resistance is 4.5 μΩcm or less.

  2-8 are preferable and, as for the number of the metal layers 12b, 2-6 are more preferable. If there are two or more metal layers 12b, the resistance value can be made sufficiently low. If the metal layer 12b is 8 layers or less, an increase in internal stress of the conductive laminate 10 can be suppressed.

The total film thickness of the metal layer 12b is preferably 25 to 60 nm, more preferably 25 to 50 nm, for example, when the target of the sheet resistance value of the conductive laminate 10 obtained is 1.5Ω / □, and the sheet resistance value is more preferable. When the target is 0.9Ω / □, 35 to 80 nm is preferable, and 35 to 70 nm is more preferable. Regarding the film thickness of each metal layer 12b, the total film thickness is appropriately distributed according to the number of metal layers 12b. In addition, since the specific resistance of each metal layer increases as the number of the metal layers 12b increases, the total film thickness tends to increase in order to decrease the resistance.
When the number of the metal layers 12b is 2 or more, the thickness of each metal layer 12b may be the same, a layer having the same thickness and a layer having a different thickness may be mixed, and each layer may be different. May be.

  The p-th oxide layer 12a (where p is an integer of 1 or more) from the base 11 and the p-th metal layer 12b from the base 11 are preferably laminated in direct contact. If it is the said structure, the metal layer 12b is formed in the oxide layer 12a surface. The specific resistance of the metal layer 12b can be reduced by forming the metal layer 12b directly on the surface of the oxide layer 12a which is a layer containing indium and tungsten as oxides. If the specific resistance of the metal layer 12b is reduced, the sheet resistance value of the conductive laminate 10 can be reduced, so that the conductive laminate 10 having excellent electromagnetic wave shielding performance can be obtained. Further, when the specific resistance of the metal layer 12b is reduced, a desired sheet resistance value in the conductive laminate 10 can be obtained even if the film thickness per layer of the metal layer 12b is reduced. As a result, it is possible to obtain the conductive laminate 10 having a low resistance and a wide visible light transmission band and a visible light reflection band.

(Method for forming conductive film)
Examples of the method of forming the conductive film 12 (oxide layer 12a, metal layer 12b) include sputtering, vacuum deposition, ion plating, chemical vapor deposition, and the like, and stability of quality and characteristics. Sputtering is particularly preferred from the viewpoint of good. Examples of the sputtering method include a pulse sputtering method and an AC sputtering method.

For example, the conductive film 12 is formed by sputtering as follows.
(I) While introducing argon gas mixed with oxygen gas, pulse sputtering is performed on the surface of the base 11 using a mixed target containing indium oxide and tungsten oxide to form the oxide layer 12a.
(Ii) While introducing argon gas, pulse sputtering is performed using a silver target or a silver alloy target to form the metal layer 12b.
(I) The conductive film 12 is formed by repeating the operation (ii) and finally forming the oxide layer 12a by the operation (i).
The mixed target can be produced by mixing high-purity (usually 99.9%) powders of each oxide, molding and sintering using a cold isostatic press or the like.

(Protective layer)
The conductive film 12 may have a protective layer 12d on the surface of the oxide layer 12a farthest from the substrate 11. The protective layer 12d is a layer that protects the oxide layer 12a and the metal layer 12b from moisture. Further, the oxide layer 12a farthest from the substrate 11 is coated with any resin film (moisture-proof film, anti-scattering film, anti-reflection film, protective film for shielding near infrared rays, functional film such as near infrared absorbing film). It is a layer that protects from an adhesive (particularly an alkaline adhesive) when adhering.

Examples of the protective layer 12d include oxide layers and nitride layers of metals such as tin, indium, titanium, and silicon, and a layer containing indium oxide and tin oxide is preferable.
2-30 nm is preferable and, as for the film thickness of 12 d of protective layers, 3-20 nm is more preferable.

(Barrier layer)
As shown in FIG. 2, the conductive film 12 may have a barrier layer 12c on the metal layer 12b. By providing the barrier layer 12c on the metal layer 12b, oxidation of the metal layer 12b can be prevented when the oxide layer 12a is formed in an oxygen atmosphere.
Examples of the barrier layer 12c include those that can be formed in the absence of oxygen. Examples of the barrier layer 12c include a layer containing zinc oxide and aluminum oxide, a layer containing indium oxide and tin oxide, and the like.

The luminous transmittance of the conductive laminate 10 is preferably 55% or more, and more preferably 60% or more.
The transmittance of the conductive laminate 10 at a wavelength of 850 nm is preferably 5% or less, and more preferably 2% or less.
The sheet resistance (surface resistance) on the conductive film 12 side of the conductive laminate 10 is preferably 0.1 to 2.5Ω / □, and preferably 0.2 to 1.5Ω / □ in order to sufficiently secure the electromagnetic wave shielding ability. □ is more preferable, and 0.3 to 0.8Ω / □ is particularly preferable.

(Use)
The conductive laminate of the present invention is excellent in conductivity (electromagnetic wave shielding), visible light transmittance and near infrared shielding property, and when laminated on a support substrate such as glass, the transmission / reflection band becomes wide. It is useful as a filter for plasma display. When used as a filter for a plasma display, the conductive laminate may be disposed on the PDP observer side as it is, or may be disposed on the PDP observer side as a plasma display protective plate described later.

Moreover, the electroconductive laminated body of this invention can be used as transparent electrodes, such as a liquid crystal display element. The transparent electrode has good responsiveness because of low surface resistance, and good visibility because the reflectance is suppressed to the same level as glass.
Moreover, the electroconductive laminated body of this invention can be used as a motor vehicle windshield. The automotive windshield can exhibit antifogging or melting ice functions by energizing the conductive film, and since it has low resistance, the voltage required for energization can be reduced, and the reflectance can be suppressed to the same level as glass. The driver's visibility is not impaired.
Moreover, since the electroconductive laminated body of this invention has the very high reflectance in an infrared region, it can be used as a heat mirror provided in the window etc. of a building.
In addition, since the conductive laminate of the present invention has a high electromagnetic shielding effect, the electromagnetic waves radiated from the electric / electronic device are prevented from leaking outside, and the electromagnetic waves that affect the electric / electronic device enter the room from the outside. It can be used for an electromagnetic wave shielding window glass that prevents intrusion.

<Protective plate for plasma display>
Hereinafter, the example which used the electroconductive laminated body of this invention for the protective plate for plasma displays (henceforth a protective plate) is demonstrated.

(First embodiment)
FIG. 3 shows the protective plate of the first embodiment. The protective plate 1 includes a support base 20, a conductive laminate 10 provided on the support base 20, a colored ceramic layer 30 provided on a peripheral portion of the surface of the support base 20 on the conductive laminate 10 side, The scattering prevention film 40 bonded to the surface of the support base 20 opposite to the conductive laminate 10 side, the electrode 50 in electrical contact with the peripheral edge of the conductive film 12 of the conductive laminate 10, and conductive And a protective film 60 provided on the conductive laminate 10. An adhesive layer 70 is provided between the conductive laminate 10 and the support base 20, between the conductive laminate 10 and the protective film 60, and between the support base 20 and the scattering prevention film 40. The protection plate 1 is an example in which the conductive laminate 10 is provided on the PDP side of the support base 20.

The support base 20 is a transparent base having higher rigidity than the base 11 of the conductive laminate 10. By providing the support base 20, even if the material of the base 11 of the conductive laminate 10 is plastic, no warp is generated due to a temperature difference generated between the PDP side and the observer side.
Examples of the support base 20 include those similar to the base 11 of the conductive laminate 10.

  The colored ceramic layer 30 is a layer for concealing the electrode 50 so as not to be directly visible from the viewer side. The colored ceramic layer 30 can be formed, for example, by printing on the support base 20 or pasting a colored tape.

The anti-scattering film 40 is a film for preventing the fragments of the supporting base 20 from scattering when the supporting base 20 is damaged. As the scattering prevention film 40, a known film can be used.
The anti-scattering film 40 may have an antireflection function. An example of a film having both a scattering prevention function and an antireflection function is Realak (trade name) manufactured by Nippon Oil & Fats Co., Ltd. Realak (trade name) is obtained by forming an antireflection layer having a low refractive index on one side of a PET film having anti-scattering properties and applying an antireflection treatment. Moreover, the film etc. which formed the antireflective layer of a low refractive index on the film which consists of plastics by the wet or dry type are mentioned.

  The electrode 50 is provided so as to be in electrical contact with the conductive film 12 so that the electromagnetic wave shielding effect by the conductive film 12 of the conductive laminate 10 is exhibited. The electrode 50 is preferably provided on the entire periphery of the conductive film 12 in order to ensure the electromagnetic wave shielding effect of the conductive film 12. The material of the electrode 50 is superior in terms of electromagnetic wave shielding ability when the resistance is lower. The electrode 50 is formed, for example, by applying and baking a silver paste containing silver and glass frit, or a copper paste containing copper and glass frit.

  The protective film 60 is a film that protects the conductive film 12 of the conductive laminate 10. In the case where the conductive film 12 is protected from moisture, a moisture-proof film is provided. Examples of the moisture-proof film include plastic films such as polyethylene terephthalate and polyvinylidene chloride. Further, the scattering prevention film may be used as the protective film 60.

  Examples of the pressure-sensitive adhesive for the pressure-sensitive adhesive layer 70 include commercially available pressure-sensitive adhesives, such as acrylic ester copolymer, polyvinyl chloride, epoxy resin, polyurethane, vinyl acetate copolymer, and styrene-acrylic copolymer. , Polyesters, polyamides, polyolefins, styrene-butadiene copolymer rubbers, butyl rubbers, silicone resins and the like, and an acrylic pressure-sensitive adhesive is particularly preferable because good moisture resistance can be obtained. The pressure-sensitive adhesive layer 70 may contain additives having various functions such as an ultraviolet absorber.

(Second Embodiment)
FIG. 4 shows a protective plate according to the second embodiment. The protective plate 2 includes a support base 20, a conductive laminate 10 provided on one side of the support base 20, an anti-scattering film 40 provided on the conductive laminate 10, and a conductive film of the conductive laminate 10. 12 is provided with an electrode 50 that is in electrical contact with the peripheral edge portion 12 and a colored ceramic layer 30 provided on the peripheral edge portion of the surface of the support base 20 opposite to the conductive laminate 10 side. Further, the scattering prevention film 40 is provided inside the electrode 50. The protection plate 2 is an example in which the conductive laminate 10 is provided on the observer side of the support base 20.
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG.

(Third embodiment)
FIG. 5 shows a protective plate according to the third embodiment. The protective plate 3 includes the support base 20, the conductive laminate 10 bonded to the surface of the support base 20 via the pressure-sensitive adhesive layer 70, and the scattering bonded to the surface of the conductive laminate 10 via the pressure-sensitive adhesive layer 70. The prevention film 40 and the colored ceramic layer 30 provided on the peripheral edge of the surface of the support base 20 opposite to the conductive laminate 10, and the peripheral edge of the conductive mesh film 80 overlap the colored ceramic layer 30. The conductive mesh film 80 bonded to the surface of the support base 20 via the adhesive layer 70, the conductive film 12 of the conductive laminate 10, and the conductive mesh layer (not shown) of the conductive mesh film 80 are electrically connected. And an electrode 90 provided on the peripheral side portion of the protective plate 3 so as to be connected to. The protection plate 3 is an example in which the conductive laminate 10 is provided on the observer side of the support base 20 and the conductive mesh film 80 is provided on the PDP side of the support base 20.
Note that in the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as in FIG. 3 and description thereof is omitted.

The conductive mesh film 80 is obtained by forming a conductive mesh layer made of copper on a transparent film. Usually, after manufacturing a copper foil on a transparent film, it manufactures by processing in a mesh form.
The copper foil may be either rolled copper or electrolytic copper, and a known one may be used as appropriate. The copper foil may be subjected to various surface treatments. Examples of the surface treatment include chromate treatment, roughening treatment, pickling, zinc / chromate treatment, and the like. 3-30 micrometers is preferable, as for the thickness of copper foil, 5-20 micrometers is more preferable, and 7-10 micrometers is especially preferable. By setting the thickness of the copper foil to 30 μm or less, the etching time can be shortened, and by setting the thickness to 3 μm or more, the electromagnetic wave shielding property is enhanced.

The opening ratio of the conductive mesh layer is preferably 60 to 95%, more preferably 65 to 90%, and particularly preferably 70 to 85%.
The shape of the opening of the conductive mesh layer is a regular triangle, a regular square, a regular hexagon, a circle, a rectangle, a rhombus, or the like. It is preferable that the openings have the same shape and are aligned in the plane.
The size of the opening is preferably 5 to 200 μm on a side or diameter, and more preferably 10 to 150 μm. By setting one side or diameter of the opening to 200 μm or less, the electromagnetic wave shielding property is improved, and by setting it to 5 μm or more, there is little influence on the image of the PDP.
The width of the metal part other than the opening is preferably 5 to 50 μm. That is, the arrangement pitch of the openings is preferably 10 to 250 μm. By making the width of the metal part 5 μm or more, processing becomes easy, and by making the width 50 μm or less, the influence on the image of the PDP is small.

  If the surface resistance of the conductive mesh layer is made lower than necessary, the film becomes thick and adversely affects the optical performance and the like of the protective plate 3 such that the openings cannot be secured sufficiently. On the other hand, if the surface resistance of the conductive mesh layer is increased more than necessary, sufficient electromagnetic wave shielding properties cannot be obtained. Therefore, the surface resistance of the conductive mesh layer is preferably 0.01 to 10Ω / □, more preferably 0.01 to 2Ω / □, and particularly preferably 0.05 to 1Ω / □.

The surface resistance of the conductive mesh layer may be measured by a four-terminal method using an electrode that is five times or more larger than one side or diameter of the opening, and an electrode interval that is five or more times larger than the arrangement pitch of the openings. For example, if the openings are squares with a side of 100 μm and are regularly arranged via a metal part with a width of 20 μm, electrodes having a diameter of 1 mm may be arranged at intervals of 1 mm. Alternatively, the conductive mesh film is processed into a strip shape, electrodes are provided at both ends in the longitudinal direction, the resistance R is measured, and the length is obtained from the longitudinal length a and the lateral length b by the following formula. May be.
Surface resistance = R × b / a.

  When laminating a copper foil on a transparent film, a transparent adhesive is used. Examples of the adhesive include acrylic adhesives, epoxy adhesives, urethane adhesives, silicone adhesives, and polyester adhesives. The adhesive type is preferably a two-component type or a thermosetting type. Moreover, as an adhesive agent, what was excellent in chemical-resistance is preferable.

  Examples of the method for processing the copper foil into a mesh shape include a printing method and a photoresist method. In the printing method, the opening pattern is formed by screen printing. In the photoresist method, a photoresist material is formed on a copper foil by a roll coating method, a spin coating method, a full surface printing method, a transfer method, and the like, and an opening pattern is formed by exposure, development, and etching.

  The electrode 90 electrically connects the conductive film 12 of the conductive laminate 10 and the conductive mesh layer of the conductive mesh film 80. Examples of the electrode 90 include a conductive tape. By electrically connecting the conductive film 12 of the conductive laminate 10 and the conductive mesh layer of the conductive mesh film 80, the overall sheet resistance value can be further reduced, thereby further improving the electromagnetic wave shielding effect. be able to.

  Since the protective plates 1 to 3 are arranged on the front surface of the PDP, the luminous transmittance is preferably 40% or more so as not to make it difficult to see the image of the PDP. Further, the luminous reflectance is preferably less than 6%, particularly preferably less than 3%. Further, the transmittance at a wavelength of 850 nm is preferably 5% or less, and particularly preferably 2% or less.

Note that the protective plate of the present invention is not limited to the first to third embodiments. For example, heat bonding may be performed without providing the pressure-sensitive adhesive layer 70.
In addition, the protective plate of the present invention may have an antireflection layer that is an antireflection film or a low refractive index thin film, if necessary. A known film can be used as the antireflection film, and a fluororesin film is preferred from the viewpoint of antireflection properties. As the antireflection layer, the reflectance of the protective plate is lowered, and a preferable reflected color is obtained. Therefore, the wavelength at which the reflectance is lowest in the visible light region is preferably 500 to 600 nm, and preferably 530 to 590 nm. Those are particularly preferred.

  Further, the protective plate may have a near infrared shielding function. As a method for providing a near-infrared shielding function, a method using a near-infrared shielding film, a method using a near-infrared absorbing substrate, a method using a pressure-sensitive adhesive added with a near-infrared absorbing agent during film lamination, an antireflection resin film, etc. Examples thereof include a method of adding an infrared absorber to have a near infrared absorption function, a method of using a conductive film having a near infrared reflection function, and the like.

  In the conductive laminate 10 described above, since the oxide layer 12a is a layer containing indium oxide and tungsten oxide, the transmission / reflection band can be widened. In addition, since the metal layer 12b is formed on the surface of the oxide layer 12a, the resistance of the metal layer 12b is reduced, and as a result, the conductivity (electromagnetic wave shielding property) is excellent. Further, since the transmission / reflection band can be widened without increasing the number of the conductive films 12 and the conductivity is excellent, the number of the conductive films 12 can be reduced, and as a result, the visible light transmittance is also excellent.

  Further, in the protective plates 1 to 3 described above, since the conductive laminate 10 having a wide transmission / reflection band and excellent in conductivity, visible light transmittance and near-infrared shielding properties is used, Excellent electromagnetic shielding properties, wide transmission and reflection bands, high visible light transmittance, and excellent near infrared shielding properties.

Examples 1 and 4 are examples, and examples 2 and 3 are comparative examples.
(Example 1)
A conductive laminate 10 shown in FIG. 2 was produced as follows. However, n was set to 3, and the protective layer 12d was not provided.

(I) While introducing argon gas mixed with 4% by volume of oxygen gas, using a mixed target [indium oxide: tungsten oxide: zinc oxide = 98.5: 1.0: 0.5 (mass ratio)] An oxide layer having a thickness of 35 nm on the surface of the glass substrate 11 that has been subjected to pulse sputtering under conditions of a pressure of 0.73 Pa, a frequency of 50 kHz, a power density of 2.5 W / cm ² , and an inversion pulse width of 2 μs, and subjected to a cleaning process. 12a (1) was formed.

(Ii) Using a silver alloy target doped with 1.0% by mass of gold while introducing argon gas, under the conditions of pressure 0.73 Pa, frequency 50 kHz, power density 2.5 W / cm ² , and inversion pulse width 10 μsec. Pulse sputtering was performed to form a metal layer 12b (1) having a thickness of 10 nm on the surface of the oxide layer 12a (1).

(Iii) While introducing argon gas, using a mixed target [zinc oxide: aluminum oxide = 95: 5 (mass ratio)], pressure 0.73 Pa, frequency 50 kHz, power density 2.5 W / cm ² , inversion pulse width Pulse sputtering was performed under the condition of 2 μs to form a 1 nm thick barrier layer 12c (1) on the surface of the metal layer 12b (1).

In the same manner as (i), an oxide layer 12a (2) having a thickness of 70 nm was formed on the surface of the barrier layer 12c (1).
In the same manner as (ii), a metal layer 12b (2) having a thickness of 10 nm was formed on the surface of the oxide layer 12a (2).
In the same manner as (iii), a barrier layer 12c (2) having a thickness of 1 nm was formed on the surface of the metal layer 12b (2).

In the same manner as (i), an oxide layer 12a (3) having a thickness of 70 nm was formed on the surface of the barrier layer 12c (2).
In the same manner as (ii), a metal layer 12b (3) having a thickness of 10 nm was formed on the surface of the oxide layer 12a (3).
In the same manner as (iii), a barrier layer 12c (3) having a thickness of 1 nm was formed on the surface of the metal layer 12b (3).

In the same manner as (i), an oxide layer 12a (4) having a thickness of 35 nm was formed on the surface of the barrier layer 12c (3).
In this manner, the oxide layers 12a made of indium oxide, tungsten oxide, and zinc oxide and the metal layers 12b made of a silver alloy containing gold are alternately stacked on the base 11, and the barriers are formed on the metal layer 12b. A conductive laminate 10 provided with a layer 12c, having four oxide layers 12a, three metal layers 12b, and three barrier layers 12c was obtained.

About the electroconductive laminated body 10 of Example 1, the luminous transmittance (stimulus value Y prescribed | regulated in JISZ8701) measured by Tokyo Denshoku color analyzer TC1800 was 75.1%. Further, the transmittance at a wavelength of 850 nm was 2.60%.
Further, the sheet resistance (surface resistance) measured by an eddy current resistance measuring device SRM12 manufactured by Nagy was 1.176 Ω / □.
FIG. 6 shows the transmission spectrum, FIG. 7 shows the reflection spectrum, and Table 1 shows the evaluation results.

For the oxide layer 12a, the atomic ratio of each element was measured by Rutherford Backscattering Spectroscopy (RBS) using Pelletron accelerator, 3UH manufactured by National Electrostatics Corporation under the following conditions.
Beam energy: 2300 keV,
Ion species: He ⁺ ,
Scattering angle: 170 degrees, 100 degrees,
Beam incident angle: 7 degrees with respect to the normal of the sample surface
Sample current: 30 nA,
Beam irradiation amount: 40 μC.

  In the total metal (100 atomic%) contained in the oxide layer 12a, indium was 98.25 atomic%, tungsten was 0.75 atomic%, and zinc was 1.0 atomic%. Therefore, the atomic ratio (W / In) between tungsten and indium in the oxide layer 12a was 0.0076, and the atomic ratio (Zn / In) between zinc and indium was 0.010. Moreover, oxygen atom was 59.8 atomic% in all the atoms (100 atomic%) in the oxide layer 12a.

(Example 2)
Example 1 except that the mixed target used for forming the oxide layer 12a was changed to a mixed target [zinc oxide: titanium oxide = 90: 10 (mass ratio)] and the film thickness of the metal layer 12b was changed to 11 nm. Similarly, a conductive laminate was obtained.
With respect to the conductive laminate of Example 2, the luminous transmittance (stimulus value Y defined in JIS Z 8701) measured with a color analyzer TC1800 manufactured by Tokyo Denshoku was 73.9%. Further, the transmittance at a wavelength of 850 nm was 1.88%.
Further, the sheet resistance (surface resistance) measured by an eddy current type resistance measuring device SRM12 manufactured by Nagy was 1.178Ω / □.
FIG. 6 shows the transmission spectrum, FIG. 7 shows the reflection spectrum, and Table 1 shows the evaluation results.

(Example 3)
Example except that the mixed target used for forming the oxide layer 12a is changed to a mixed target [indium oxide: tin oxide = 90: 10 (mass ratio)] and the film thickness of the metal layer 12b is changed to 10.5 nm. In the same manner as in Example 1, a conductive laminate was obtained.
With respect to the conductive laminate of Example 3, the luminous transmittance (stimulus value Y defined in JIS Z 8701) measured with a color analyzer TC1800 manufactured by Tokyo Denshoku was 73.3%. Further, the transmittance at a wavelength of 850 nm was 2.21%.
The sheet resistance (surface resistance) measured by an eddy current resistance measuring device SRM12 manufactured by Nagy was 1.161 Ω / □.
FIG. 6 shows the transmission spectrum, FIG. 7 shows the reflection spectrum, and Table 1 shows the evaluation results.

  In Table 1, a wavelength band showing a transmittance of 60% or more is defined as a transmission bandwidth. The transmittance at 850 nm indicates near infrared shielding performance. Further, a wavelength band showing a reflectance of 10% or less was defined as a reflection bandwidth.

(Example 4)
A conductive laminate 10 shown in FIG. 1 was produced as follows. However, n was set to 3, and the protective layer 12d was not provided.

(I) While introducing argon gas mixed with 4% by volume of oxygen gas, using a mixed target [indium oxide: tungsten oxide: zinc oxide = 98.5: 1.0: 0.5 (mass ratio)] An oxide layer having a thickness of 35 nm on the surface of the glass substrate 11 that has been subjected to pulse sputtering under conditions of a pressure of 0.73 Pa, a frequency of 50 kHz, a power density of 2.5 W / cm ² , and an inversion pulse width of 2 μs, and subjected to a cleaning process. 12a (1) was formed.

(Ii) Using a silver alloy target doped with 1.0% by mass of gold while introducing argon gas, under the conditions of pressure 0.73 Pa, frequency 50 kHz, power density 2.5 W / cm ² , and inversion pulse width 10 μsec. Pulse sputtering was performed to form a metal layer 12b (1) having a thickness of 10 nm on the surface of the oxide layer 12a (1).

In the same manner as (i), an oxide layer 12a (2) having a thickness of 70 nm was formed on the surface of the metal layer 12b (1).
In the same manner as (ii), a metal layer 12b (2) having a thickness of 10 nm was formed on the surface of the oxide layer 12a (2).

In the same manner as (i), an oxide layer 12a (3) having a thickness of 70 nm was formed on the surface of the metal layer 12b (2).
In the same manner as (ii), a metal layer 12b (3) having a thickness of 10 nm was formed on the surface of the oxide layer 12a (3).

In the same manner as (i), an oxide layer 12a (4) having a thickness of 35 nm was formed on the surface of the metal layer 12b (3).
In this way, the conductive laminate 10 in which the oxide layers 12a made of indium oxide, tungsten oxide and zinc oxide and the metal layers 12b made of a silver alloy containing gold are alternately laminated on the substrate 11 is obtained. Thus, four oxide layers 12a and three metal layers 12b were obtained.

With respect to the conductive laminate 10 of Example 4, the luminous transmittance (stimulus value Y defined in JIS Z 8701) measured by a color analyzer TC1800 manufactured by Tokyo Denshoku was 76.2%. Further, the transmittance at a wavelength of 850 nm was 3.95%.
The sheet resistance (surface resistance) measured by an eddy current resistance measuring device SRM12 manufactured by Nagy was 1.161 Ω / □.
FIG. 8 shows the transmission spectrum, FIG. 9 shows the reflection spectrum, and Table 2 shows the evaluation results.
When the atomic ratio of each element was measured in the same manner as in Example 1 for the oxide layer 12a, the same results as in Example 1 were obtained.

  The conductive laminate and protective plate of the present invention are useful as a plasma display filter because they have excellent conductivity (electromagnetic wave shielding property), visible light transmittance and near-infrared shielding property, and a wide transmission / reflection band. is there. Moreover, the electroconductive laminated body of this invention can be used as transparent electrodes, such as a liquid crystal display element, a motor vehicle windshield glass, a heat mirror, and an electromagnetic wave shielding window glass.

It is sectional drawing which shows an example of the electroconductive laminated body of this invention. It is sectional drawing which shows the other example of the electroconductive laminated body of this invention. It is sectional drawing which shows 1st Embodiment of the protection board of this invention. It is sectional drawing which shows 2nd Embodiment of the protection board of this invention. It is sectional drawing which shows 3rd Embodiment of the protection board of this invention. It is a graph which shows the transmission spectrum in the electroconductive laminated body of Examples 1, 2, and 3. FIG. It is a graph which shows the reflection spectrum in the electroconductive laminated body of Examples 1, 2, and 3. FIG. 10 is a graph showing a transmission spectrum in the conductive laminate of Example 4. 10 is a graph showing a reflection spectrum in the conductive laminate of Example 4.

Explanation of symbols

1 Protection plate (Plasma display protection plate)
2 Protection plate (Protection plate for plasma display)
3 Protection plate (Protection plate for plasma display)
DESCRIPTION OF SYMBOLS 10 Conductive laminated body 11 Base body 12 Conductive film 12a Oxide layer 12b Metal layer 20 Support base body 50 Electrode 80 Conductive mesh film

Claims (7)

A conductive laminate having a base and a conductive film formed on the base,
The conductive film has a total of (2n + 1) layers of oxide layers and metal layers alternately from the substrate side [where n is an integer of 1 or more. ] Is a laminated multilayer structure,
The oxide layer is a layer containing indium and tungsten as oxides;
A conductive laminate, wherein the metal layer is a layer containing silver or a silver alloy as a main component.   The conductive laminate according to claim 1, wherein the oxide layer is a layer further containing one or more selected from the group consisting of zinc and silicon as an oxide.   The conductive laminate according to claim 1 or 2, wherein an atomic ratio (W / In) of tungsten and indium in the oxide layer is 0.001 to 0.035.   The electroconductive laminated body in any one of Claims 1-3 whose number of metal layers is 2-8.   The electroconductive laminate according to any one of claims 1 to 4, wherein the metal layer is a layer made of pure silver or a layer made of a silver alloy containing at least one selected from gold, palladium, and bismuth. A support substrate;
The conductive laminate according to claim 1 provided on the support substrate,
A protective plate for plasma display, comprising: an electrode in electrical contact with the conductive film of the conductive laminate. The protective plate for plasma display according to claim 6, further comprising a conductive mesh film.

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