JP4470443B2 - PDP filter - Google Patents

Description

  The present invention relates to a PDP filter that is directly attached to the front surface of a plasma display panel (PDP), and more particularly to an improved PDP filter that reduces or eliminates warping due to heat.

  As an electromagnetic wave shielding material for blocking electromagnetic waves leaking from a PDP, a PDP filter having a conductive layer formed on a glass substrate to provide an electromagnetic wave shielding function is used (for example, JP 2002-57489 A).

  FIG. 2 is a schematic cross-sectional view showing the electromagnetic wave shielding member disclosed in the same publication. The electromagnetic wave shielding member 11 includes adhesive interlayers 14A and 14B serving as adhesives between two transparent substrates 12A and 12B. The electromagnetic shielding heat ray cut film 13 is laminated and integrated, and a black frame coating 16 based on acrylic resin is provided on the peripheral edge of the transparent substrate 12B on the back surface side.

  This electromagnetic wave shielding member 11 is prepared by preparing a transparent glass substrate 12A on which an antireflection film 15 is formed, a transparent glass substrate 12B on which a black frame coating 16 is provided, an electromagnetic wave shielding heat ray cut film 13 and adhesive intermediate films 14A and 14B. Then, between the transparent substrate 12A and the transparent substrate 12B, a film in which the electromagnetic wave shielding heat ray cut film 13 is sandwiched between the adhesive intermediate films 14A and 14B is laminated, and added under the curing conditions of the adhesive intermediate films 14A and 14B. Manufactured by integration under heating or light irradiation.

  The PDP filter having such a glass substrate is installed at a predetermined distance from the front surface of the PDP main body. Thereby, the influence of the heat from the PDP main body is small, and the required value of the thermal durability characteristics such as the film and adhesive of the PDP filter is relaxed.

  On the other hand, in recent years, it has been studied that a film-like PDP filter is directly attached to the PDP body as the amount of heat generated by the PDP body decreases. Thus, in the PDP in which the PDP filter is directly attached to the PDP main body, the gap between the PDP filter and the PDP main body is eliminated, and the thickness of the PDP is reduced accordingly.

An example of a PDP filter directly attached to a PDP main body is described in JP-A-2002-189422. The PDP filter of the same publication has a pigment-containing resin layer formed on a base film, and an antireflection layer may be formed on the other side of the base filter.
JP 2002-57489 A JP 2002-189422 A

  In a film-type PDP filter that is directly attached to a PDP and does not have a glass substrate, warpage occurs due to a difference in the thermal shrinkage rate of the film that constitutes the PDP filter in the temperature lowering process during the production of the PDP filter. Sometimes.

  It is an object of the present invention to provide a PDP filter with no or very little warpage.

The PDP filter of the present invention is a PDP filter whose back side is directly bonded to the plasma display panel, and in the PDP filter having a plurality of laminated films, the base film and the front side and the back side of the base film and a provided a functional film, thermal shrinkage of the front film and the back side of the heat shrinkage of the film and is substantially V equal, and, the main shrinkage direction and back surface side of the surface side film of the main shrinkage direction of the film is characterized in substantially equal Ikoto.

  According to the present invention, since the thermal shrinkage rate of the film on the front surface side and the film on the back surface side of the PDP filter is substantially equal, it is possible to prevent the PDP filter from being warped during manufacture of the PDP filter.

  Embodiments of a PDP filter according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a PDP filter. In FIG. 1, in order to clarify the laminated structure of the PDP filter, each layer is shown separately, but these are all laminated and integrated.

  This PDP filter 1 has an antireflection film 2 on the outermost surface, and the antireflection film 2, the electromagnetic wave shielding layer 3, the transparent base film 4 and the near infrared cut film 5 are laminated and adhered by adhesive layers 7A, 7B, and 7C. The adhesive layer 8 is provided on the back side of the near-infrared cut film 5 and the release paper 6 is attached. The black frame part 9 is formed on the peripheral part on the back side of the outermost antireflection film 2. Yes.

  The heat shrinkage rate of the antireflection film 2 on the outermost surface and the heat shrinkage rate of the near-infrared cut film 5 on the backmost surface are substantially equal, preferably the latter heat shrinkage rate is 90 to 110% of the former heat shrinkage rate, especially 95. ~ 105%. Moreover, both main shrinkage directions are the same.

  Thereby, the warpage of the PDP filter 1 is preferably within 5 mm, particularly within 4 mm.

  Preferably, all films of the PDP filter have substantially the same heat shrinkage rate, and their main shrinkage directions are all the same. The main shrinkage direction coincides with the maximum stretching direction during film production.

  In order to make the thermal shrinkage rate of the films substantially equal, it is preferable to anneal each film at a temperature higher than the highest temperature among the annealing temperatures of each film (preferably a temperature higher by about 60 to 200 ° C.).

As the antireflection film 2, a monolayer film of the following (1) on a transparent base film (thickness is, for example, about 25 to 250 μm) such as PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), etc. In addition, a laminated film of a high refractive index transparent film and a low refractive index transparent film, for example, a film in which a laminated film having a laminated structure as shown in (2) to (5) below is formed.
(1) One layer of a transparent film having a lower refractive index than the constituent material of the panel to which the electromagnetic wave shielding light-transmitting laminated film is attached. (2) Total of one high refractive index transparent film and one low refractive index transparent film. Laminated in two layers (3) Laminated high-refractive-index transparent film and low-refractive-index transparent film alternately in total 4 layers (4) Medium refractive index transparent film / High refractive index transparent film / Low refractive index One layer in the order of the transparent film, laminated in a total of three layers (5) Three layers in the order of high refractive index transparent film / low refractive index transparent film, three layers in turn, laminated in a total of six layers

As the high refractive index transparent film, a thin film having a refractive index of 1.6 or more, preferably a transparent conductive thin film, such as ITO (tin indium oxide) or ZnO, Al doped ZnO, TiO ₂ , SnO ₂ , ZrO, etc. Can be formed. The high refractive index transparent film may be a thin film in which these fine particles are dispersed in an acrylic or polyester binder. Further, as the low refractive index transparent film, a thin film made of a low refractive index material having a refractive index of 1.6 or less such as SiO ₂ , MgF ₂ , Al ₂ O ₃ can be formed. As the low refractive index transparent film, a thin film made of a silicon-based or fluorine-based organic material is also suitable. These film thicknesses vary depending on the film configuration, film type, and center wavelength in order to lower the reflectance in the visible light region due to light interference, but in the case of a four-layer structure, the first layer on the panel attachment side (high refraction) 5 to 50 nm, the second layer (low refractive index transparent film) is 5 to 50 nm, the third layer (high refractive index transparent film) is 50 to 100 nm, and the fourth layer (low refractive index transparent film) is It is formed with a film thickness of about 50 to 150 nm.

  The hard coat layer 1a may be formed on such an antireflection film 2. The hard coat layer 1a is preferably a hard resin such as acrylic or silicone, and the thickness is preferably about 0.1 to 10 μm.

  A black frame portion 9 is formed on the antireflection film 2 by printing or the like. The width of the black frame portion 9 is slightly different depending on the size of the electromagnetic wave shielding member, but is usually 5 to 50 mm.

  In this way, by forming the black frame portion 9 on the back surface of the antireflection film 2 on the outermost surface, scratches or intrusions from the edge portions of the electromagnetic shielding layer 3, the near infrared cut film 4 and the transparent substrate 5 in the lower layer thereof. Even if there is a defect such as a foreign matter, the defect is concealed by the black frame portion 9 and is not visible from the surface side.

  As the electromagnetic wave shielding layer 3, a conductive mesh, an etching mesh, a conductive printing mesh, a transparent conductive film, or the like can be used.

  As the conductive mesh, a metal mesh and / or metal-coated organic fiber is used. In the present invention, in order to improve light transmission and prevent moire phenomenon, for example, a wire diameter of 1 μm to 1 mm, an opening is used. Those with a rate of 40-95% are preferred. In this conductive mesh, when the wire diameter exceeds 1 mm, the aperture ratio decreases or the electromagnetic wave shielding property decreases, and both cannot be achieved. If it is less than 1 μm, the strength as a mesh is lowered, and handling becomes very difficult. Further, if the aperture ratio exceeds 95%, it is difficult to maintain the shape as a mesh, and if it is less than 40%, the light transmittance is low, and the amount of light from the display is reduced. A more preferable wire diameter is 10 to 500 μm, and an aperture ratio is 50 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.

  Metals constituting the conductive mesh and metal of the metal-coated organic fiber include copper, stainless steel, aluminum, nickel, titanium, tungsten, tin, lead, iron, silver, chromium, carbon or alloys thereof, preferably copper, Nickel, stainless steel, and aluminum are used.

  As the organic material for the metal-coated organic fiber, polyester, nylon, vinylidene chloride, aramid, vinylon, cellulose and the like are used.

  In the present invention, it is particularly preferable to use a conductive mesh made of metal-coated organic fibers excellent in mesh shape maintenance characteristics, in order to maintain the aperture ratio and the wire diameter.

  As the etching mesh, a metal film etched into an arbitrary shape such as a lattice shape or a punching metal shape by a photolithography technique can be used. As this metal film, a metal film such as copper, aluminum, stainless steel and chromium formed on a transparent base film such as PET, PC, PMMA, etc. by vapor deposition or sputtering, or these metal foils are transparent with an adhesive. What was bonded to the base film can be used. As this adhesive, epoxy-based, urethane-based, EVA-based and the like are preferable.

  These metal films are preferably previously black printed on one or both sides. By using a photolithography technique, the shape and wire diameter of the conductive portion can be freely designed, so that the aperture ratio can be increased as compared with the conductive mesh.

  As the conductive printing mesh, metallic particles such as silver, copper, aluminum, nickel, or non-metallic conductive particles such as carbon are mixed with an epoxy-based, urethane-based, EVA-based, melanin-based, cellulose-based, acrylic-based binder, or the like. What was printed with a pattern such as a lattice on a transparent base film such as PET, PC, PMMA, etc. by gravure printing, offset printing, screen printing, or the like can be used.

  As the transparent conductive film, a resin film in which conductive particles are dispersed or a substrate film having a transparent conductive layer formed thereon can be used.

The conductive particles dispersed in the film are not particularly limited as long as they have conductivity, and examples thereof include the following.
(i) Carbon particles or powder
(ii) Particles or powders of metals or alloys such as nickel, indium, chromium, gold, vanadium, tin, cadmium, silver, platinum, aluminum, copper, titanium, cobalt, lead or their conductive oxides
(iii) The surface of plastic particles such as polystyrene and polyethylene formed with a coating layer of the conductive material (i) or (ii) above
(iv) Alternating laminate of ITO and silver

  The particle diameter of these conductive particles is preferably 0.5 mm or less because excessively large particle size affects the light transmittance and the thickness of the transparent conductive film. The preferable particle diameter of the conductive particles is 0.01 to 0.5 mm.

  Further, the mixing ratio of the conductive particles in the transparent conductive film is too high if the light transmittance is impaired, and if it is too low, the electromagnetic shielding property is insufficient. 0.1 to 50% by weight, particularly 0.1 to 20% by weight, and particularly preferably about 0.5 to 20% by weight.

  The color and gloss of the conductive particles are appropriately selected according to the purpose, but for use as a PDP filter, dark and non-glossy colors such as black and brown are preferable. In this case, the conductive particles appropriately adjust the light transmittance of the filter, so that the screen can be easily viewed.

  As what formed the transparent conductive layer in the base film, what formed the transparent conductive layers, such as a tin indium oxide and zinc aluminum oxide, by vapor deposition, sputtering, ion plating, CVD etc. is mentioned. In this case, when the thickness of the transparent conductive layer is less than 0.01 μm, the thickness of the conductive layer for electromagnetic wave shielding is too thin, and sufficient electromagnetic wave shielding properties cannot be obtained. May be damaged.

  In addition, as a resin for matrix resin or base film of transparent conductive film, polyester, PET, polybutylene terephthalate, PMMA, acrylic plate, PC, polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, Ethylene-vinyl acetate copolymer, polyvinyl butyral, metal ion cross-linked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc., preferably PET, PC, PMMA.

  The thickness of such a transparent conductive film is usually about 1 μm to 5 mm.

  As the constituent material of the base film 4, polyester, PET, polybutylene terephthalate, PMMA, acrylic, PC, polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl Butyral, metal ion crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, etc., preferably PET, PC, PMMA.

  In general, the thickness of the base film 4 is preferably about 0.05 to 1 μm.

  As the near-infrared cut film 5, a transparent base film and two or more near-infrared cut layers as a near-infrared cut layer, preferably a combination of two or more near-infrared cut material layers, This is preferable in that remarkably good near infrared absorption performance can be obtained in a wide wavelength range of the near infrared.

In the present invention, the near infrared cut layer can be configured as follows.
(1) A first near-infrared cut film in which a coating layer of a first near-infrared cut material is provided on a base film, and a second near-infrared cut different from the first near-infrared cut material on the base film Combination with a second near-infrared cut film provided with a coating layer of material
(2) A coating layer of a first near-infrared cut material provided on one surface of the base film and a second near-infrared cut material coating layer different from the first near-infrared cut material on the other surface Near infrared cut film
(3) A near-infrared cut film provided by laminating a coating layer of a first near-infrared cut material and a coating layer of a second near-infrared cut material different from the first near-infrared cut material on a base film.

  As the near-infrared cut film 5, a transparent conductive material such as copper-based, phthalocyanine-based, zinc oxide, silver, ITO (indium tin oxide), nickel complex-based, diimonium-based, etc. A material provided with a coating layer can be used. As this base film, a film made of PET, PC, PMMA or the like can be preferably used. This base film is preferably about 10 μm to 1 mm in order to ensure handleability and durability without excessively increasing the thickness of the obtained electromagnetic wave shielding light-transmitting laminated film. Moreover, the thickness of the near-infrared cut coating layer formed on this base film is about 0.5-50 micrometers normally.

  In the present invention, a near-infrared cut layer using preferably two or more kinds of the near-infrared cut materials may be provided, or two or more kinds of coating layers may be mixed, laminated, or base film. It may be coated separately on both sides, or two or more near infrared cut films may be laminated.

In particular, in the present invention, as the near-infrared cut material, the use of a combination of two or more near-infrared cut materials with different near-infrared cut types as described below provides good near-infrared cut performance without impairing transparency. (For example, in the wide wavelength range of near infrared rays, such as 850-1250 nm, it is preferable when obtaining the capability of fully absorbing near infrared rays).
(A) 100 to 5000 ＩＴＯ thick ITO coating layer (b) 100 to 10000 と thick ITO and silver coating layer (c) 0.5 to 50 micron thick nickel complex system and imonium system (D) Coating layer (e) having a copper compound containing divalent copper ions having a thickness of 10 to 10000 microns using a suitable transparent binder (e) ) An organic dye-based coating layer having a thickness of 0.5 to 50 microns is suitable, but not limited thereto.

  In the present invention, for example, the transparent conductive film described above may be further laminated together with the near infrared cut film.

  As the adhesive resin that constitutes the adhesive layers 7A, 7B, and 7C, a transparent and elastic resin, for example, an adhesive that is usually used as an adhesive for laminated glass is preferable.

  Specific examples of the resin having such elasticity include an ethylene-vinyl acetate copolymer, an ethylene-methyl acrylate copolymer, an ethylene- (meth) acrylic acid copolymer, and an ethylene- (meth) acrylic. Ethyl acid copolymer, ethylene- (meth) acrylic acid methyl copolymer, metal ion crosslinked ethylene- (meth) acrylic acid copolymer, partially saponified ethylene-vinyl acetate copolymer, carboxyl ethylene-vinyl acetate copolymer , Ethylene- (meth) acrylic-maleic anhydride copolymers, ethylene-based copolymers such as ethylene-vinyl acetate- (meth) acrylate copolymers (in addition, “(meth) acrylic” means “acrylic or Methacryl "). In addition, polyvinyl butyral (PVB) resin, epoxy resin, acrylic resin, phenol resin, silicon resin, polyester resin, urethane resin, and the like can also be used.

  The thickness of the adhesive layers 7A, 7B, and 7C is preferably about 10 to 1000 μm, for example.

  The adhesive layers 7A, 7B, and 7C may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, and a paint processing aid, and a dye for adjusting the color of the filter itself. An appropriate amount of a colorant such as a pigment, a filler such as carbon black, hydrophobic silica, or calcium carbonate may be blended.

  The adhesive sheet for forming the adhesive layers 7A, 7B, and 7C is formed by mixing an adhesive resin and the above-described additives, kneading them with an extruder, a roll, and the like, and then forming a calendar, a roll, a T-die extrusion, an inflation, and the like. It is manufactured by forming a sheet into a predetermined shape by a membrane method. During film formation, embossing is applied to prevent blocking and facilitate degassing during pressure bonding. As means for improving adhesiveness, means such as corona discharge treatment, low temperature plasma treatment, electron beam irradiation, and ultraviolet light irradiation to the adhesive sheet are also effective.

  As the pressure-sensitive adhesive (pressure-sensitive adhesive) of the pressure-sensitive adhesive layer 8, a thermoplastic elastomer such as acrylic, SBS, SEBS, or the like is preferably used. To these pressure-sensitive adhesives, tackifiers, ultraviolet absorbers, colored pigments, colored dyes, anti-aging agents, adhesion-imparting agents, and the like can be appropriately added. The thickness of the pressure-sensitive adhesive layer 8 is preferably about 10 to 1000 μm. An appropriate release paper (film) 6 is attached to the adhesive layer 8 as shown in FIG.

  FIG. 1 is a diagram showing an example of the PDP filter of the present invention, and the present invention is not limited to the illustrated one as long as the gist thereof is not exceeded.

  The outermost film is not limited to the antireflection film, and may be an antiglare film in which a light-diffusing layer is formed by applying a resin coating containing silica on a transparent film. As an antiglare film, the surface of the light diffusing layer is provided with irregularities by agglomeration of particles such as cohesive silica, and resin beads having a particle diameter larger than the thickness of the coating film are added to provide irregularities on the surface. There are those obtained by using a shaped film having irregularities on the surface, laminating on the surface of the coating film not solidified to transfer the irregular shape, and then peeling the shaped film.

  This PDP filter may have a protective film attached to the outermost surface.

  In this case, it is desirable that the thermal shrinkage rate of the protective film is substantially equal to the thermal shrinkage rate of the near-infrared cut film 5 on the backmost surface.

It is sectional drawing which shows embodiment of the electromagnetic wave shielding member of this invention. It is sectional drawing of the conventional electromagnetic wave shielding member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PDP filter body 2 Antireflection film 3 Electromagnetic wave shield layer 4 Base film 5 Near infrared cut film 6 Release paper 7A, 7B, 7C Adhesive layer 8 Adhesive layer 9 Black frame part

Claims (5)

In the PDP filter whose back side is directly bonded to the plasma display panel and having a plurality of laminated films,
A base film, and a functional film provided on the front side and the back side of the base film,
Heat shrinkage ratio of the surface side of the film and the back side of the heat shrinkage of the film and is substantially V equal, and a main shrinkage direction of the main shrinkage direction of the back surface side film of the surface side film is substantially equal A PDP filter characterized by that. Oite to claim 1, PDP filters, characterized by being annealed at a temperature higher than the highest annealing temperature of the annealing temperature of each film. According to claim 1 or 2, the PDP filter, wherein the antireflection film or an antiglare film on the outermost surface of the PDP filter is provided. In any one of claims 1 to 3, PDP filter body, PDP filter, comprising a near-infrared absorbing film or color tone correction film. In any one of claims 1 to 4, the PDP filter, the PDP filter, which is a film type PDP filter having no glass substrate.

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