JP2008191395A - Near-infrared absorption filter for plasma display panel and plasma display panel - Google Patents

Abstract

A near-infrared absorption filter for PDP that has a large near-infrared absorptivity, is excellent in transparency and durability, and can be manufactured at low cost, and a PDP using the filter.
SOLUTION: The near-infrared absorption at an average dispersed particle diameter of 800 nm or less and a dispersed aggregate at a wavelength of 1200 nm to 1800 nm in an adhesive layer or / and an external force absorbing layer in a laminate constituting a near-infrared absorption filter for PDP. By dispersing the tungsten oxide fine particles and / or composite tungsten oxide fine particles having the maximum of the above, a near-infrared absorption filter for PDP that has a large near-infrared absorbing power, excellent transparency and durability, and can be produced at low cost is obtained. .
[Selection] Figure 1

Description

  The present invention has a plasma display panel (hereinafter sometimes referred to as PDP) having an adhesive layer and / or an external force absorbing layer on a substrate and a laminate having a near infrared shielding property provided on the substrate surface. The present invention relates to a near-infrared absorption filter for a plasma display panel that absorbs near-infrared rays radiated from the light emitting portion toward the front surface of the PDP, and a plasma display panel using this filter.

In recent years, PDPs have attracted attention as displays become larger and thinner. In addition to the purpose of screen protection, a filter provided with optical functions such as antireflection and color correction is installed on the surface of the PDP. In addition, details of functions required for the PDP optical filter will be described below.
(1) Near-infrared shielding function From the xenon gas used for phosphor emission of the PDP, near-infrared light is also generated at the same time in the plasma discharge process, and a part thereof is radiated to the front surface of the PDP. In particular, near-infrared rays in the wavelength range of 800 nm to 1100 nm are problematic in that they cause malfunctions of cordless phones and home appliance remote controls, and adverse effects on transmission optical communication. For this reason, near infrared rays shielding processing is given to the front surface of PDP for the purpose of preventing the above-mentioned malfunction.

  The near-infrared shielding process is performed by providing a near-infrared absorber as a filter on the front surface of the PDP. The near-infrared absorber has a visible light region (wavelength region, about 380 nm) so as not to adversely affect the luminance of the PDP. (˜780 nm) light is sufficiently transmitted, and near infrared rays having a wavelength range of 800 nm to 1100 nm are required to be shielded. As a PDP filter that absorbs near-infrared rays, conventionally, a filter in which an organic dye or a metal complex is used in combination or coated in multiple layers has been proposed.

  When an organic compound or a metal complex is used as a filter, a method of coating a base material on the surface of the PDP with a solution obtained by dissolving the organic compound or the metal complex in a solvent is generally used. Here, as a near-infrared absorber such as organic compounds and metal complexes, diimonium compounds, aminium compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds Compounds, triphenylmethane compounds, and the like. However, since these near-infrared absorbers such as organic compounds and metal complexes have low resistance to heat and light and are likely to deteriorate over time, when these organic compounds and metal complexes are used as near-infrared absorbers, the performance is prolonged. There was a problem that it was difficult to hold.

  In addition, since the near-infrared absorber has poor durability, a layer having a near-infrared shielding function cannot be provided in the vicinity of the viewing surface side surface of the PDP optical filter that is easily affected by the external environment, and is in contact with the substrate. It has been common to provide an independent layer on the surface side or the PDP bonding side. For this reason, the structure as a PDP optical filter is limited, and the number of stacked layers increases, resulting in a decrease in productivity and an increase in cost.

  On the other hand, in Patent Document 1, tungsten oxide fine particles or / and composite tungsten oxide fine particles are used as inorganic near-infrared absorbers having excellent weather resistance, and a resin or metal oxide provided in or on the substrate surface. Although a near-infrared absorption filter for PDP dispersed in an object film has been disclosed, a simpler layer structure has not been realized.

Moreover, in patent document 2, the said tungsten oxide type compound is used as a near-infrared absorber, the hard-coat layer containing hardening resin and a near-infrared absorber on one surface of a base film, and also the low refractive index containing hardening resin Constructs an antireflection film in which the layers are sequentially laminated and the transmittance in the entire range of at least 850 to 1000 nm is 30% or less, has near infrared absorption performance and antireflection performance, and has excellent scratch resistance There has been proposed an antireflection film that has a simple layer structure and is low in cost, and that can be obtained by a wet process method particularly suitable for PDP.
(2) Electromagnetic wave shielding function Moreover, in PDP, electromagnetic waves are generated simultaneously during the plasma discharge process. Leaked electromagnetic waves may affect other devices and the human body, and it is required to keep the intensity of electromagnetic wave emission within the standard. Therefore, an optical filter for PDP is generally provided with an electromagnetic wave shielding layer. Is. As a method for shielding the electromagnetic wave, a method of providing a conductive layer for shielding the electromagnetic wave on the surface of the substrate is used. For example, a method of laminating conductive thin films of metal / metal oxide on the substrate surface in multiple layers, a method of etching a thin film layer of a metal foil such as copper into a mesh shape, and the like can be mentioned.

When the mesh-like metal layer or metal-containing layer is used, the surface of the base material provided with the mesh is rough, so that a transparent resin layer that fills the gap between the meshes is used to improve the transparency of the optical filter. There is also a case. In Patent Document 3, an adhesive layer is laminated on a transparent substrate, and an electromagnetic wave shielding adhesive film in which a conductive layer of a geometrical figure is embedded in the adhesive layer is bonded to a plastic plate to shield the electromagnetic wave. There is disclosed a display using the electromagnetic wave shielding adhesive film or the electromagnetic wave shielding structural body as a structure on the front surface of a display such as a CRT, PDP, liquid crystal, EL or the like.
(3) External force absorbing function Further, as the display becomes larger, further weight reduction and thickness reduction are required, and improvement of the impact resistance of the panel has become an important issue. Therefore, in addition to the near-infrared shielding layer and the electromagnetic wave shielding layer, Patent Document 4 proposes to provide an impact relaxation layer that absorbs external force applied to the panel and relaxes the impact. As the external force absorbing layer, a resin layer such as polyurethane, ethylene vinyl acetate copolymer, and polyolefin is separately provided.

In order to meet all of the above requirements, the latest PDP optical filters are mainly composed of multilayer films in which a near-infrared shielding layer, an electromagnetic wave shielding layer, an external force absorption layer, etc. are separately produced and bonded together with an adhesive or the like to form a composite film. It has become. However, due to the multi-layer structure, the transparency of the filter is lowered to affect the brightness of the screen, and the productivity is deteriorated and the cost is increased.
JP 2006-154516 A JP 2006-201443 A JP 2000-323891 A JP 2006-293239 A

  The present invention has been made paying attention to such problems, and the problem is that the near-infrared absorbing filter for PDP, which has a large near-infrared absorbing power, has excellent durability, and can be manufactured at low cost, and the filter. It is to provide a PDP using the.

  In order to solve the above problems, the present inventors have conducted extensive research from the viewpoint of improving the weather resistance of a near infrared absorption filter for PDP and reducing the number of layers to reduce the cost. A near-infrared absorption filter for a plasma display panel having an adhesive layer and / or an external force absorption layer in a laminate having a near-infrared shielding property provided on the surface of a material, can transmit visible light and shield near-infrared rays. As inorganic material fine particles having good weather resistance, fine particles of tungsten oxide and / or composite tungsten oxide having an average dispersed particle diameter of 800 nm or less and a dispersion aggregate having a near-infrared absorption maximum at a wavelength of 1200 nm to 1800 nm, By using an inorganic material for the adhesive layer and / or external force absorbing layer, near infrared shielding performance and weather resistance Excellent, and found that for PDP near infrared absorption filter which realizes high transparency by reducing the number of laminated layers is obtained.

That is, the first invention of the present invention is for a plasma display panel having a base material and an adhesive layer, or an adhesive layer and an external force absorbing layer in a laminate having a near infrared shielding property provided on the surface of the base material. Near infrared absorption filter
In the adhesive layer, tungsten oxide fine particles and / or composite tungsten oxide fine particles having an average dispersed particle diameter of 800 nm or less and a dispersion aggregate having a near infrared absorption maximum at a wavelength of 1200 nm to 1800 nm are dispersed. A near-infrared absorption filter for a plasma display panel is provided.

  A second aspect of the present invention is the plasma display panel according to the first aspect, wherein a mesh-like metal layer or metal-containing layer having an electromagnetic wave shielding function is embedded in the adhesive layer. Provide near infrared absorption filter.

  The third invention of the present invention is characterized in that the adhesive component contained in the adhesive layer is composed of one or more selected from an acrylic adhesive, a urethane adhesive, an ester adhesive, and a silicone adhesive. The near-infrared absorption filter for plasma display panels described in the first and second inventions is provided.

4th invention of this invention is for plasma display panels which have a base material and the external force absorption layer in the laminated body which has the near-infrared shielding provided on this base-material surface, or a contact bonding layer and an external force absorption layer. Near infrared absorption filter
In the external force absorption layer, tungsten oxide fine particles and / or composite tungsten oxide fine particles having an average dispersed particle diameter of 800 nm or less and a dispersion aggregate having a near infrared absorption maximum at a wavelength of 1200 nm to 1800 nm are dispersed. A near-infrared absorbing filter for a plasma display panel is provided.

  According to a fifth aspect of the present invention, the external force absorbing component contained in the external force absorbing layer is an acrylic polymer, ethylene vinyl acetate copolymer, silicone resin, polystyrene ethylene butylene styrene block copolymer, polyurethane, polyethylene, poly A near-infrared absorption filter for a plasma display panel according to the fourth invention, comprising at least one selected from vinyl chloride, polyolefin, polystyrene, and polypropylene.

  According to a sixth aspect of the present invention, the adhesive layer or the external force absorbing layer further includes a diimonium compound, an aminium compound, a phthalocyanine compound, an organometallic complex, a cyanine compound, an azo compound, a polymethine compound, and a quinone compound. A near-infrared absorbing filter for a plasma display panel according to any one of the first to fifth inventions, which contains at least one organic compound selected from the group consisting of diphenylmethane compounds and triphenylmethane compounds I will provide a.

  In a seventh aspect of the present invention, the tungsten oxide fine particles are formed of a tungsten oxide represented by a general formula WyOz (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999). A near-infrared absorption filter for a plasma display panel according to any one of the first to sixth inventions, wherein the filter is a fine particle.

  According to an eighth aspect of the present invention, the composite tungsten oxide fine particles have the general formula MxWyOz (where the M element is H, He, an alkali metal, an alkaline earth metal, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, One or more elements selected from S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, W is tungsten, O is oxygen, 0 .001 ≦ x / y ≦ 1.1, 2.2 ≦ z / y ≦ 3.0), which is a composite tungsten oxide fine particle represented by any one of 1 to 6 Providing near-infrared absorption filters for plasma display panels

  In a ninth aspect of the present invention, the tungsten oxide fine particles or / and the composite tungsten oxide fine particles have a general formula WyOz (W is tungsten, O is oxygen, 2.45 ≦ z / y ≦ 2.999). A near-infrared absorption filter for a plasma display panel according to any one of the first to fifth inventions, comprising a magnetic phase having a composition ratio represented by:

According to a tenth aspect of the present invention, there is provided a near-infrared shielding laminate according to any one of the first to ninth aspects, on both surfaces of a base material. Provide infrared absorption filter.
An eleventh aspect of the present invention provides a plasma display panel comprising the near-infrared absorption filter for plasma display panels according to any one of the first to tenth aspects.

  The near-infrared absorbing filter for PDP of the present invention has an adhesive layer and / or an external force absorbing layer in a substrate and a laminate having a near-infrared shielding property provided on the surface of the substrate, and absorbs near-infrared rays. High strength, excellent durability, and low cost production.

  In the infrared shielding filter for PDP of the present invention, the average dispersed particle diameter is 800 nm or less and the dispersion aggregate has a wavelength as the weatherable near-infrared absorbing inorganic material fine particles that can transmit visible light and shield near-infrared rays. Since fine particles of tungsten oxide and / or composite tungsten oxide having a near infrared absorption maximum at 1200 nm to 1800 nm are used, the weather resistance and heat resistance of the optical filter are remarkably improved, and the brightness of the PDP main body is increased. While maintaining a sufficient visible light transmittance without deteriorating, it is possible to provide a near-infrared shielding property that can avoid malfunction of peripheral devices. In addition, the tungsten oxide fine particles or / and the composite tungsten oxide fine particles are dispersed separately in the adhesive layer or / and the external force absorbing layer in the laminate provided on the surface of the base material, so that they have been provided separately until now. Since the adhesive layer or / and the external force absorbing layer and the near-infrared shielding layer can be made into one layer, the number of laminated optical filters is reduced to improve the transparency, and at the same time, the productivity is reduced and the cost is reduced by reducing the number of processes. be able to.

  Furthermore, the plasma display panel using the near-infrared absorption filter for PDP of the present invention has high transparency and visible light transmittance, and is excellent in near-infrared shielding, so that the brightness of the PDP main body is not reduced. It is possible to avoid a situation in which a surrounding electronic device malfunctions due to near infrared rays generated from the PDP main body.

  Hereinafter, embodiments of the present invention will be described in detail.

  The near-infrared absorption filter for PDP according to the present invention has an adhesive layer and / or an external force absorption layer in a substrate and a laminate having a near-infrared shielding property provided on the surface of the substrate, and emits visible light. Tungsten oxide having an average dispersed particle diameter of 800 nm or less and a dispersed aggregate having a maximum of near-infrared absorption at a wavelength of 1200 nm to 1800 nm as inorganic material fine particles having good weather resistance that can transmit and shield near infrared rays And fine particles of composite tungsten oxide are used by being dispersed in the adhesive layer and / or the external force absorbing layer.

  The near-infrared absorption filter for PDP in the present invention is required to have a near-infrared absorption maximum at a wavelength of 1200 nm to 1800 nm, and the transmittance in the wavelength region is 20% or less, more preferably 10% or less. desirable. If the transmittance in the above wavelength region is larger than 20%, a sufficient near infrared shielding function cannot be obtained.

  In addition, the near-infrared absorption filter for PDP in the present invention needs to have sufficient transparency and visible light transmittance in order to maintain the clearness of the screen. Specifically, it is preferable that the visible light transmittance is 40% or more and the haze value is 5% or less. When the visible light transmittance is less than 40% or the haze value is greater than 5%, the brightness of the screen is lowered and a clear image cannot be obtained.

Next, the material used for the near-infrared absorption filter for PDP according to the present invention will be specifically described below.
(Transparent substrate)
The substrate applied to the near-infrared absorption filter for PDP of the present invention is not particularly limited as long as it is a material having high transparency to visible light, but generally a plastic film is used, and polyethylene terephthalate, polybutylene is used. Examples include terephthalate, polymethyl methacrylate, acrylic resin, polycarbonate, triacetyl cellulose, and polystyrene.
Here, the tungsten oxide fine particles and / or the composite tungsten oxide fine particles may be kneaded into a resin constituting the base material to form a plastic board or a plastic film, which may be used as a transparent base material having a near infrared absorption function.
(Tungsten oxide fine particles, composite tungsten oxide fine particles)
The tungsten oxide fine particles applied to the near-infrared absorption filter for PDP of the present invention are represented by the general formula WyOz (where W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999). The tungsten oxide fine particles function effectively as a near-infrared absorbing component.

Here, examples of tungsten oxide fine particles represented by the general formula WyOz (2.2 ≦ z / y ≦ 2.999) include W ₁₈ O ₄₉ , W ₂₀ O ₅₈ , and W ₄ O _11. . If the value of z / y is 2.2 or more, it is possible to completely avoid the appearance of an undesired WO ₂ crystal phase in the heat-absorbing material and to obtain the chemical stability of the material. I can do it. On the other hand, if the value of z / y is 2.999 or less, a sufficient amount of free electrons is generated and an efficient near-infrared absorbing material is obtained. A WyOz compound having a z / y range of 2.45 ≦ z / y ≦ 2.999 is a compound called a so-called Magneli phase and has excellent durability.

  Next, the general formula MxWyOz (wherein M element is H, He, alkali metal, alkaline earth metal, rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, One or more elements selected from Mo, Ta, Re, Be, Hf, Os, Bi, I, W is tungsten, O is oxygen, 0.001 ≦ x / y ≦ 1.1, 2.2 The composite tungsten oxide fine particles represented by ≦ z / y ≦ 3.0) also function effectively as a near-infrared absorbing component.

  The composite tungsten oxide fine particles represented by the general formula MxWyOz is excellent in durability when it has a hexagonal, tetragonal or cubic crystal structure, and is therefore selected from the hexagonal, tetragonal and cubic crystals. Preferably it contains more than one crystal structure. For example, in the case of composite tungsten oxide fine particles having a hexagonal crystal structure, preferable M elements include Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn. Examples thereof include composite tungsten oxide fine particles containing one or more selected elements.

At this time, the added amount x of the M element is preferably 0.001 or more and 1.1 or less in x / y, and more preferably around 0.33. This is because the value of x / y calculated theoretically from the hexagonal crystal structure is 0.33, and preferable optical characteristics can be obtained with the addition amount before and after this. On the other hand, the abundance Z of oxygen is preferably 2.2 or more and 3.0 or less in z / y. Typical examples include Cs _0.33 WO ₃ , Rb _0.33 WO ₃ , K _0.33 WO ₃ , Ba _0.33 WO _3, etc., but useful if x, y and z are within the above ranges. Near infrared absorption characteristics can be obtained.

  The tungsten oxide fine particles and the composite tungsten oxide fine particles described above may be used alone or in combination.

  Further, if the surfaces of the tungsten oxide fine particles and / or composite tungsten oxide fine particles are covered with an oxide containing one or more elements of Si, Ti, Zr, and Al, the weather resistance is further improved. Can be preferred.

  Since the near-infrared absorbing filter having a film in which the near-infrared absorbing material is dispersed is a near-infrared absorbing filter for PDP, the near-infrared absorbing material should efficiently absorb near-infrared while maintaining transparency. Is required. Here, the near-infrared absorbing component containing the tungsten oxide fine particles and / or composite tungsten oxide fine particles according to the present invention greatly absorbs light in the near-infrared region, particularly in the vicinity of a wavelength of 900 to 2200 nm. There are many things that turn from blue to green.

On the other hand, the tungsten oxide fine particles and / or composite tungsten oxide fine particles, which are the near-infrared absorbing material, are dispersed in the coating containing the resin or metal oxide formed on the base material, or both. , the content is, when expressed in content per unit area is preferably between ^{0.01g / m 2 ~10g / m 2} . If the content is more than 0.01 g / m ² , a sufficient near-infrared absorption effect appears, and if it is 10 g / m ² or less, a sufficient amount of visible light can be transmitted.

When the tungsten oxide fine particles or / and the composite tungsten oxide fine particles are applied as a near-infrared absorbing material, the transmittance in the visible light region at a wavelength of 380 nm to 780 nm is high, and the transmittance in the near infrared region at a wavelength of 780 nm to 1500 nm. Lower. The decrease in transmittance at the wavelength of 780 nm to 1500 nm is considered to be caused by absorption reflection caused by plasmon resonance due to conduction electrons in the tungsten oxide or composite tungsten oxide. Further, in the visible light region in the wavelength range of 380 nm to 780 nm, the amount of absorption is small compared to the absorption in the vicinity of the wavelength of 1000 nm, and thus visibility is maintained well. As a result, even if a near-infrared absorbing filter having a film in which the near-infrared absorbing material is dispersed is installed on the front surface of the display, the screen display can be confirmed sufficiently clearly, which is preferable.
(Adhesive layer)
As a first embodiment of the present invention, an near-infrared absorbing fine particle is dispersed in an adhesive layer that serves to connect a base material and other constituent layers, and an adhesive layer having a near-infrared shielding function is provided. Thereby, since the adhesive layer and the near-infrared shielding layer which have been separately provided so far can be made into one layer, it is preferable. The adhesive component contained in the adhesive layer is not particularly limited as long as it has sufficient adhesiveness. For example, an acrylic adhesive, an ester adhesive, a urethane adhesive, Examples thereof include silicone adhesives and mixtures thereof. Moreover, although the preferable thickness of the said contact bonding layer is based also on the addition amount of the near-infrared absorption fine particle to an adhesive component, it is the range of 5-50 micrometers, and 10-30 micrometers is especially preferable.
(Adhesive layer with electromagnetic shielding function)
Further, the adhesive layer having the near infrared shielding function can have an electromagnetic wave shielding function in addition to the near infrared shielding function. By forming a structure in which a mesh-like metal layer or metal-containing layer having an electromagnetic shielding function is embedded in an adhesive layer having a near infrared shielding function, three functions of a near infrared shielding function, an electromagnetic shielding function, and an adhesion function are provided. Can be achieved with one layer.

  The type of mesh electromagnetic wave shielding layer is not particularly limited as long as it has electromagnetic wave shielding properties, but copper, iron, nickel, chromium, aluminum, gold, silver, stainless steel, tungsten, chromium, Examples include those obtained by etching a metal foil such as titanium or an alloy thereof into a mesh shape, or those obtained by pattern-printing a conductive ink in which conductive fine particles such as carbon black, copper, and nickel are dispersed in a binder resin. be able to.

In the case of a mesh-like metal layer, the mesh preferably has a wire diameter of 1 μm to 1 mm and an aperture ratio of 50 to 90% made of metal fibers and / or metal-coated organic fibers. A more preferable wire diameter is 10 to 500 μm, and an aperture ratio is 60 to 90%. The opening ratio of the conductive mesh refers to the area ratio occupied by the opening portion in the projected area of the conductive mesh.
(External force absorption layer)
Further, as another embodiment of the present invention, a near-infrared shielding function is provided by dispersing near-infrared absorbing fine particles in an external force absorbing layer for mitigating the impact applied to the panel and preventing damage to the PDP. An external force absorbing layer having Thereby, since the external force absorption layer and the near-infrared shielding layer which were provided separately until now can be made into one layer, it is preferable.

  The external force absorbing component contained in the external force absorbing layer is not particularly limited as long as it is a substance having high external force absorbability. For example, acrylic polymer, ethylene vinyl acetate copolymer, silicone resin, polystyrene ethylene butylene styrene Block copolymer, polyurethane, polyethylene, polyvinyl chloride, polyolefin, polystyrene, polypropylene, ethylene acrylate copolymer, polyamide resin, polybutyral resin, epoxy resin, phenol resin, polyvinyl butyral, polystyrene, polyolefin, polydiene, Thermoplastic elastomers showing rubber elasticity such as vinyl chloride, polyurethane, polyester, polyamide, fluorine, chlorinated polyethylene, polystyrene / polyolefin copolymers, and mixtures of these It is below.

In particular, at least one selected from acrylic polymer, ethylene vinyl acetate copolymer, silicone resin, polystyrene ethylene butylene styrene block copolymer, polyurethane, polyethylene, polyvinyl chloride, polyolefin, polystyrene, polypropylene Is more preferable.
Moreover, although the preferable thickness of the said external force absorption layer is based also on the addition amount of the near-infrared absorption fine particle to an external force absorption component, it is the range of 0.3-1.5 mm.
(External force absorption layer with adhesive function)
When the external force absorbing component has sufficient adhesiveness, an external force absorbing layer can be used as the adhesive layer. By dispersing the near-infrared absorbing fine particles of the present invention in an external force-absorbing layer having adhesiveness, an adhesive function, an external-force absorbing function, and a near-infrared shielding function can be provided in one layer, which is preferable.
In particular, when a mesh-like metal layer or metal-containing layer having an electromagnetic wave function is embedded in an external force absorbing layer having an adhesive function, the four functions of a near infrared shielding function, an adhesive function, an electromagnetic wave shielding function, and an external force absorbing function are combined into one function. It is preferable that it can be combined with the layer.
(Other constituent layers)
In addition, the other constituent layers of the laminate in the infrared absorbing filter for PDP include an antireflection layer for preventing reflection of external light, a color tone correction layer for improving color reproducibility of an image, and surface contamination. Examples thereof include an antistatic layer for preventing, and a hard coat layer for improving scratch resistance.

  In addition to the adhesive layer having a near-infrared shielding function and / or an external force absorbing layer according to the present invention, the tungsten oxide or / and composite tungsten oxide fine particles, organic near-infrared absorption in one or more of the above constituent layers It is also possible to improve the near infrared shielding function by adding a material.

  Of the constituent layers, the antireflection layer will be briefly described. As a technique used for the antireflection layer, a method for preventing reflection by diffusing and scattering light by roughening a light incident surface, and alternately laminating a high refractive index material and a low refractive index material. There are methods for suppressing surface reflection.

Examples of the high refractive index material to be used include a transparent resin having a high refractive index and a material obtained by adding high refractive index fine particles to a resin. It is preferable to use ultraviolet shielding fine particles such as ZnO and CeO ₂ as the high refractive index fine particles because the ultraviolet shielding function can be imparted to the filter. In addition, it is preferable to use conductive fine particles such as ITO and ATO since antistatic curing is imparted and dust can be prevented from adhering to the screen.

  Moreover, examples of the low refractive index material used include a material in which silica fine particles are mixed with a sol fluorine resin dispersed in water or an organic solvent.

In order to form each layer of the antireflection layer, for example, a coating solution obtained by diluting the above materials with a solvent or the like is applied on a substrate by a method such as gravure coating, dried, and then cured by heat or ultraviolet rays. Good. In order to maintain transparency as an optical filter for PDP, the visible light transmittance of the high refractive index layer and the low refractive index layer is preferably 85% or more.
(Manufacturing method of near infrared absorption filter for PDP)
Next, an adhesive layer or / and an external force absorbing layer are provided in the laminate having near-infrared shielding provided on the substrate surface, and tungsten oxide fine particles or / and in the adhesive layer or / and the external force absorbing layer. An example of a method for producing a near-infrared absorption filter for PDP in which composite tungsten oxide fine particles are dispersed will be described.
(Preparation of near-infrared absorbing fine particle dispersion)
When the tungsten oxide and / or composite tungsten oxide is used as a near-infrared absorber, it is preferable to use a fine particle dispersion method as an industrially inexpensive and simple method. This is a method in which the tungsten oxide fine particles and the composite tungsten oxide fine particles are uniformly dispersed in a resin or coating provided on the filter base material, and near infrared rays transmitted therethrough are shielded.

  When producing a near-infrared absorption filter for a plasma display panel by the fine particle dispersion method, the particle diameter of the fine particles of the tungsten oxide and / or composite tungsten oxide needs to be 800 nm or less, preferably 200 nm or less, More preferably, it is 100 nm or less. When the particle diameter of tungsten oxide or composite tungsten oxide fine particles exceeds 800 nm, the light in the visible light region having a wavelength of 380 nm to 780 nm emitted from the PDP is scattered by geometrical scattering or Mie scattering. This is because it looks like frosted glass and a clear screen display cannot be obtained. When the particle diameter is 200 nm or less, the geometric scattering or Mie scattering is reduced, and a Rayleigh scattering region is obtained. In the Rayleigh scattering region, the scattered light is reduced in inverse proportion to the sixth power of the particle diameter, so that the visible light scattering is reduced and a clear screen display is possible. Further, it is more preferable that the particle diameter is 100 nm or less because scattered light is extremely reduced. On the other hand, if the particle diameter is 1 nm or more, industrial production is easy.

  Various methods such as a dry method and a wet method can be used to disperse the tungsten oxide and composite tungsten oxide fine particles, but the wet method is particularly effective when dispersing tungsten oxide and composite tungsten oxide of 200 nm or less. Specific examples include a ball mill, a sand mill, a medium stirring mill, and ultrasonic irradiation.

  Moreover, it becomes easy to stably disperse and hold the tungsten oxide and composite tungsten oxide fine particles of 200 nm or less in the liquid by adding various dispersing agents at the time of fine particle dispersion and adjusting the pH. Various types of dispersants can be selected depending on the compatibility with the solvent and binder used, and typical examples include silane coupling agents and various surfactants.

  In addition, the above tungsten oxide fine particles or / and composite tungsten oxide fine particles and diimonium compounds, aminium compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds In combination with one or more organic compounds selected from compounds and triphenylmethane compounds, the organic compounds are compensated for weaknesses such as inferior heat resistance and weather resistance, and inorganic and organic near infrared rays In the absorbent material, it is also preferable to exhibit the advantages of each other.

  Next, the prepared dispersion is mixed with an appropriate adhesive or / and an external force absorbing material, uniformly applied to the substrate surface or the surface of the laminate provided on the substrate surface, and cured by an appropriate method to be PDP. A near infrared absorption filter for use is obtained. The near-infrared shielding function can be adjusted by changing the mixing ratio of the adhesive or / and the external force absorbing material and the dispersion or the film thickness of the near-infrared shielding layer.

  Furthermore, an appropriate ultraviolet absorber, antioxidant, light stabilizer, thickener, etc. are added to any one or more of the dispersion of the near infrared absorbing material, the adhesive having the near infrared absorbing material, and the external force absorbing material. By blending, it is also preferable to improve the protective function and durability on the filter surface and to improve the workability when forming the film.

a) Configuration in which an electromagnetic wave shielding layer, an external force absorption layer, and an antireflection layer are formed on different surfaces of the substrate surface A schematic cross-sectional view of an example of the basic configuration of the near infrared absorption filter for PDP of the present invention is shown in FIG. . An electromagnetic wave shielding layer 2 is provided on one surface of the transparent substrate 1a, and the transparent substrate 1b is bonded via an adhesive layer 3a formed so as to fill the gap between the two. An antireflection layer 4 is provided on the other surface of the transparent substrate 1b. An external force absorbing layer 5 is provided on the other surface of the transparent substrate 1a, and is adhered to the glass surface of the display body via the adhesive layer 3b. When the external force absorbing layer 5 has sufficient adhesiveness, the adhesive layer 3 b may be omitted and the external force absorbing layer 5 may be bonded to the glass surface via 5.

  The tungsten oxide fine particles and / or composite tungsten oxide fine particles of the present invention are dispersed in one or more of the adhesive layers 3a and 3b and the external force absorbing layer 5, and the PDP optical filter has a near infrared shielding function. I have it. Thereby, the adhesive layer or external force absorption layer and the near infrared ray shielding layer which have been provided separately so far can be made into one layer, which is preferable.

b) Configuration in which an external force absorbing layer and an antireflection layer are formed on the same side of the substrate surface Next, FIG. 2 shows a schematic sectional view of an example of the basic configuration of the optical filter of the present invention. An electromagnetic wave shielding layer 2 is provided on the surface of the transparent substrate 1a, and is further attached to the transparent substrate 1b via an adhesive layer 3a formed so as to fill the gap between the two. An external force absorbing layer 5 is provided on the other surface of the transparent substrate 1b, and an antireflection layer 4 is further provided thereon. The other surface of the transparent substrate 21a is bonded to the glass surface of the display body through the adhesive layer 3b.

  The tungsten oxide fine particles and / or composite tungsten oxide fine particles of the present invention are dispersed in one or more of the adhesive layers 3a and 3b and the external force absorbing layer 5, and the PDP optical filter has a near infrared shielding function. I have it. Thereby, the adhesive layer or external force absorbing layer and the near infrared ray shielding layer, which have been separately provided so far, and the electromagnetic wave shielding layer can be formed into one layer, which is preferable.

c) Configuration in which electromagnetic wave shielding layer, external force absorption layer, and antireflection layer are formed on the same side of the substrate surface Next, FIG. 3 shows a schematic sectional view of an example of the basic configuration of the optical filter of the present invention. An electromagnetic wave shielding layer 2 is provided on the surface of the transparent substrate 1a, and an external force absorbing layer 5 is attached via an adhesive layer 3a formed so as to fill the gap between the two, and the antireflection layer 4 is further formed thereon. Is provided. When the adhesive layer 3b has a sufficient external force absorbing function, the external force absorbing layer 5 may be omitted. The other surface of the transparent substrate 1a is bonded to the glass surface of the display body via the adhesive layer 3b.

  The tungsten oxide fine particles and / or composite tungsten oxide fine particles of the present invention are dispersed in one or more of the adhesive layers 3a and 3b and the external force absorbing layer 5, and the PDP optical filter has a near infrared shielding function. I have it. Thereby, the adhesive layer or external force absorbing layer and the near infrared ray shielding layer, which have been separately provided so far, and the electromagnetic wave shielding layer can be formed into one layer, which is preferable.

  Hereinafter, although an example is given and explained concretely, the present invention is not limited to these examples.

  In each of the following examples, the light transmittance was measured using a spectrophotometer U-4000 (manufactured by Hitachi, Ltd.) and measured at 5 nm intervals in the wavelength range of 300 nm to 2600 nm by a method according to JIS A 5759.

  The haze value of the film was measured based on JIS K 7105.

In addition, the film thickness of the coating layer having a near-infrared shielding function was set such that the maximum transmittance in the visible light region with a wavelength of 380 nm to 780 nm was about 60 to 70%.
(Example 1)
In the structure of FIG. 1, an example in which near-infrared absorbing fine particles are added to the adhesive layer 3b is shown.

Dispersion A was prepared by mixing 18.5 parts by weight of Cs _0.33 WO ₃ powder, 63 parts by weight of 4-methyl-2-pentanone, and 18.5 parts by weight of a dispersant, and performing dispersion treatment. 1 part by weight of this liquid A and 15 parts by weight of a urethane thermosetting adhesive (solid content 20%) were mixed to prepare a near-infrared shielding adhesive B.

  A photoresist was applied on the copper foil formed on the surface of the PET film 1a having a thickness of 50 μm, and after drying, the mesh pattern was exposed with a photomask, and an etching process was performed to form a mesh resist pattern. Further, the copper foil was etched, the resist layer was peeled off, and an electromagnetic wave shielding film in which the electromagnetic wave shielding layer 2 was formed on the PET film 1a was obtained.

  On the other surface of the PET film 1a, an acrylic UV curable resin having an external force absorption function is applied and cured using an applicator to form an external force absorption layer 5 and further shields near infrared rays on the external force absorption layer 5. An adhesive layer 3b having a near infrared shielding function was formed by applying and curing the adhesive B.

  Separately, a commercially available antireflection film in which an antireflection layer 4 is formed on a TAC film 1b having a thickness of 50 μm is prepared, and a urethane thermosetting adhesive layer 3a formed so as to fill a gap between the copper meshes 2 is used. It was bonded to the TAC film 1b to obtain a near-infrared shielding filter for PDP.

As a result of measuring the optical characteristics of this filter, it was found that the visible light transmittance was 56% and the haze was 2.3%, which sufficiently transmitted visible light and maintained high transparency. Furthermore, it turned out that it has a high near-infrared shielding function with the minimum value of the near-infrared transmittance of wavelengths 1200 nm to 1800 nm being 1% or less.
(Example 2)
In the structure of FIG. 1, an example in which near-infrared absorbing fine particles are added to the adhesive layer 3a is shown.

  The near-infrared shielding adhesive B is applied with an applicator so as to fill the gap between the copper meshes 2 to form an adhesive layer 3a having both a near-infrared shielding function and an electromagnetic wave shielding function. A near-infrared shielding filter for PDP was obtained in the same manner as in Example 1 except that the adhesive layer 3b was formed using an ultraviolet curable resin.

As a result of measuring the optical characteristics of this filter, it was found that the visible light transmittance was 55% and the haze was 3.0%, which sufficiently transmitted visible light and maintained high transparency. Furthermore, it turned out that it has a high near-infrared shielding function with the minimum value of the near-infrared transmittance of wavelengths 1200 nm to 1800 nm being 1% or less.
(Example 3)
In the structure of FIG. 1, an example in which near-infrared absorbing fine particles are added to the adhesive layer 5 is shown.

  20 parts by weight of liquid A, 80 parts by weight of an acrylic ultraviolet curable resin having an external force absorbing function, and 0.3 parts by weight of a photopolymerization initiator were mixed to obtain a near infrared shielding adhesive D having an external force absorbing function. A near-infrared shielding filter for PDP was obtained in the same manner as in Example 1 except that a normal urethane-based adhesive was used for the adhesive layers 3a and 3b, and the liquid D was used for the external force absorbing layer 5.

As a result of measuring the optical characteristics of this filter, it was found that the visible light transmittance was 58% and the haze was 2.6%, which sufficiently transmitted visible light and maintained high transparency. Furthermore, it turned out that it has a high near-infrared shielding function with the minimum value of the near-infrared transmittance of wavelengths 1200 nm to 1800 nm being 1% or less.
(Comparative Example 1)
In the structure of FIG. 1, a urethane-based adhesive that does not contain near-infrared absorbing fine particles is used for both of the adhesive layers 3a and 3b, and an acrylic ultraviolet curable resin that does not contain near-infrared absorbing fine particles is used for the external force absorbing layer 5. In the same manner as in Example 1, an optical filter for PDP was used. When the optical characteristics of this filter were measured, the visible light transmittance was as high as 80% and the visible light was sufficiently transmitted. However, the transmittance at a wavelength of 800 nm was as high as 90% and the near infrared transmittance was high, and the near infrared shielding function was lacking.

It is a schematic sectional drawing of an example which shows the basic composition of the near-infrared absorption filter for PDP of this invention. It is a schematic sectional drawing of another example which shows the basic composition of the near-infrared absorption filter for PDPs of this invention. It is a schematic sectional drawing of another example which shows the basic composition of the near-infrared absorption filter for PDPs of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Transparent base material 2 Electromagnetic wave shielding layer 3a, 3b Adhesion layer 4 Antireflection layer 5 External force absorption layer

Claims (11)

A near-infrared absorption filter for a plasma display panel having a base material, an adhesive layer in a laminate having near-infrared shielding provided on the surface of the base material, or an adhesive layer and an external force absorption layer,
In the adhesive layer, tungsten oxide fine particles and / or composite tungsten oxide fine particles having an average dispersed particle diameter of 800 nm or less and a dispersion aggregate having a near infrared absorption maximum at a wavelength of 1200 nm to 1800 nm are dispersed. A near-infrared absorbing filter for plasma display panels characterized by the above.   The near-infrared absorption filter for a plasma display panel according to claim 1, wherein a mesh-like metal layer or metal-containing layer having an electromagnetic wave shielding function is embedded in the adhesive layer.   The adhesive component contained in the adhesive layer is composed of at least one selected from an acrylic adhesive, a urethane adhesive, an ester adhesive, and a silicone adhesive. Near-infrared absorption filter for plasma display panels. A near-infrared absorbing filter for a plasma display panel having a base material, an external force absorbing layer in a laminate having near-infrared shielding provided on the base material surface, or an adhesive layer and an external force absorbing layer,
In the external force absorption layer, tungsten oxide fine particles and / or composite tungsten oxide fine particles having an average dispersed particle diameter of 800 nm or less and a dispersion aggregate having a near infrared absorption maximum at a wavelength of 1200 nm to 1800 nm are dispersed. A near-infrared absorbing filter for a plasma display panel.   The external force absorbing component contained in the external force absorbing layer is an acrylic polymer, ethylene vinyl acetate copolymer, silicone resin, polystyrene ethylene butylene styrene block copolymer, polyurethane, polyethylene, polyvinyl chloride, polyolefin, polystyrene, polypropylene. 5. The near-infrared absorption filter for plasma display panel according to claim 4, comprising at least one selected.   In addition to the adhesive layer or external force absorbing layer, diimonium compounds, aminium compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds, triphenylmethane compounds The near-infrared absorption filter for plasma display panels according to any one of claims 1 to 5, comprising at least one organic compound selected from compounds.   The tungsten oxide fine particles are tungsten oxide fine particles represented by a general formula WyOz (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999). Item 7. A near-infrared absorption filter for plasma display panels according to any one of items 1 to 6.   The composite tungsten oxide fine particles have the general formula MxWyOz (where the M element is H, He, alkali metal, alkaline earth metal, rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir). Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti , Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, one or more elements, W is tungsten, O is oxygen, 0.001 ≦ x / y ≦ 1. The near-infrared absorption filter for a plasma display panel according to any one of claims 1 to 6, wherein the fine particle is a composite tungsten oxide represented by 1, 2.2≤z / y≤3.0) .   The tungsten oxide fine particles or / and the composite tungsten oxide fine particles have a composition phase represented by the general formula WyOz (W is tungsten, O is oxygen, 2.45 ≦ z / y ≦ 2.999). The near-infrared absorption filter for plasma display panels according to any one of claims 1 to 5, wherein   A near-infrared absorption filter for a plasma display panel, wherein the laminate having the near-infrared shielding property according to any one of claims 1 to 9 is formed on both surfaces of a substrate.   A near-infrared absorption filter for a plasma display panel according to claim 1 is provided.

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