JP2007279463A - Front surface plate filter for plasma display panel and plasma display panel display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front surface plate filter for plasma display panel (PDP) which can reduce reflection on a front surface of a PDP and both surfaces contacting with air layers of the front surface plate filter for the PDP and is excellent in visibility, and to provide a PDP display device. <P>SOLUTION: The front surface plate filter for PDP is characterized in that a circularly polarizing plate is disposed on the surface of the inner surface side of the front surface plate filter for PDP and a reflection prevention layer is disposed on the surface of the outer surface side of the front surface plate filter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a front plate filter for a plasma display panel (hereinafter referred to as PDP) and a PDP display device provided with the same.

In recent years, a PDP display device that is thin and used for a large screen is one of the display devices that have received much attention. This PDP is a panel in which a discharge space is formed between a pair of glass substrates and a phosphor layer that emits light by discharge is provided.
The display device requires a front filter having a certain transmittance in order to obtain contrast in a bright place, and is adjusted by providing a dye layer on the front surface including adjustment with the display color. The PDP generates strong electromagnetic waves, near infrared rays, and ultraviolet rays because of its operation principle, and thus needs to be shielded. For example, in the case of electromagnetic waves, it can be shielded by a mesh layer obtained by etching copper foil in a lattice shape, and near infrared rays and ultraviolet rays can be shielded by mixing an absorbent into an adhesive material or film. Therefore, the front filter of the PDP has functions of shielding electromagnetic waves, near infrared rays, ultraviolet rays, etc., adjusting color tone, and adjusting contrast. Furthermore, since the display portion of the PDP is generally low in strength, it is necessary to protect it, and the front filter must also have a function as a protective layer.

The front filter requiring multi-functionality as described above may be directly bonded to the surface of the PDP, but is often provided as a front plate filter via an air layer on the front surface of the PDP from the viewpoint of protecting the PDP display unit. .
When the surface of the display device is flat, there is a problem that external light such as a fluorescent lamp is reflected, the contrast of the image is lowered, and the screen is difficult to see. When the front plate is used in the PDP, there is a problem that the reflection of external light is reflected three or more times because it has an air layer of several mm between the PDP.
In order to prevent such external light from moving in, a film comprising an antireflection layer having a light diffusion function and a low reflection function on the front surface of the PDP, and an optical filter plate having antireflection treatments on both sides have been proposed ( Patent Document 1). However, according to the study by the present inventors, there is a disadvantage that the image is whitish because it has a light diffusion function on the front surface of the PDP, and reflection of external light is also caused by an optical filter plate (front plate for PDP). The inner surface side of the filter) was particularly insufficient.

On the other hand, it has been proposed to improve the visibility of display by providing a circularly polarizing plate on the outer surface or inner surface of the front side substrate of the PDP (Patent Document 2). Therefore, when I installed a circularly polarizing plate on the outer surface of the front substrate, in the case of the front plate filter system through the air layer, it was not possible to prevent external light reflection on both sides of the front plate, The reflection on the surface of the polarizing plate itself was also large.
On the other hand, a filter has been proposed in which a circularly polarizing plate is provided outside a conductive mesh type electromagnetic shielding material to prevent reflection of external light from the electromagnetic shielding material (Patent Document 2). When this method is used for a display device provided with a front panel filter for PDP, the external light reflection of the electromagnetic wave shielding material is somewhat effective, but the reflection at the interface with the air layer having a large external light reflection cannot be prevented. Therefore, it was insufficient. Since the circularly polarizing plate is provided outside the electromagnetic shielding material, in the case of the PDP front plate filter, the display surface of the PDP and the inner surface of the filter could not be prevented from being reflected by the circularly polarizing plate. According to the study by the present inventors, it has been found that this is due to the fact that the circularly polarized light passing through the circularly polarizing plate is disturbed by the laminate having various functions of the PDP front plate filter. Further, it was found that the major factor of the reflection was the front surface of the PDP and both surfaces in contact with the air layer of the PDP front plate filter.
JP 2000-156182 A JP 11-242933 A JP 2003-195576 A

  Therefore, the present invention reduces the reflection on both the front surface of the PDP and the air surface of the PDP front plate filter, which is a major factor of the reflection, and has a high visibility PDP front plate filter and PDP display. To provide an apparatus.

As a result of intensive studies to solve the above problems, the present inventors have installed a circularly polarizing plate and an antireflection layer to suppress reflection at the interface with the air of the PDP display device. As a result, the present inventors have completed the present invention.
That is, the present invention
(1) A front plate filter for a plasma display panel, wherein a circularly polarizing plate is provided on the inner surface of the filter, and an antireflection layer is provided on the outer surface of the front plate filter. Face plate filter.
(2) The front plate filter for a plasma display panel according to (1), wherein an antireflection layer having a visibility reflectance of 1% or less is provided.
(3) Use a circularly polarizing plate having a reflectance on the mirror surface in the visible light region of the circularly polarizing plate, the reflectance at a wavelength of 550 nm is 1% or less, and the reflectance at wavelengths of 400 nm and 700 nm is 8% or less. (1) or the front filter for plasma display panels as described in (2) characterized by the above-mentioned.
(4) A plasma display panel display device comprising the plasma display panel front plate filter according to any one of (1) to (3).

  The front plate filter for a plasma display panel of the present invention can reduce reflection at the air interface, and the plasma display panel display device using the same has less visibility of external light and is excellent in visibility. .

The present invention will be specifically described with reference to FIGS.
FIG. 1 is a schematic diagram of a PDP display device, which includes a PDP 2 and a PDP front plate filter 1, and there is an air layer between the PDP 2 and the PDP front plate filter 1. The PDP 2 has a plasma emission region 7 between the front glass 6 and the rear glass 8. In the plasma light emitting region 7, a rare gas is enclosed as a discharge gas, and ultraviolet light is generated by plasma discharge between the electrodes, and the phosphor in the plasma light emitting region 7 emits light by this ultraviolet light. Due to this principle of operation, strong electromagnetic waves, near infrared rays, ultraviolet rays, and the like are generated. Therefore, in addition to correcting the contrast and color tone with the filters, the filters shield the electromagnetic waves and the near infrared rays and the ultraviolet rays. The PDP front plate filter 1 is provided with a functional film laminate 3 or 5 such as an electromagnetic wave shielding functional layer, a near infrared shielding layer, an ultraviolet shielding layer, a color tone correction layer, and a contrast adjustment layer on the front or back of the filter glass 4. Thus, electromagnetic wave shielding, near infrared shielding, ultraviolet shielding, color tone correction, and contrast adjustment are performed. All of these functional films may be aggregated in the functional film laminate 5 or may be divided and laminated into the functional film laminate 3. Moreover, you may provide all the functions in the functional film laminated body 3. FIG.

The filter glass 4 is required to be a transparent material having high rigidity because it is necessary to impart mechanical strength. Therefore, glass, tempered glass, and semi-tempered glass are used as the material.
When high rigidity can be realized as the polymer material, for example, high rigidity materials such as polycarbonate and polyacrylate may be used.
As the electromagnetic wave shielding functional layer, a mesh type or a metal transparent conductive film type can be used. As the mesh type, one obtained by etching copper into a mesh shape or one patterned by plating with a mesh can be used, and a fibrous mesh type can be used. As the metal transparent conductive film type, a transparent resin film obtained by laminating a transparent metal such as ITO or Ag or a thin film of a metal compound by a sputtering method or the like can be used.

The near-infrared shielding layer uses a gold-infrared absorbing material having absorption in a region near 800 to 1000 nm in order to prevent malfunction of a remote controller or the like due to near-infrared rays emitted from the PDP. As this gold infrared absorbing substance, a near infrared absorbing dye such as a nitroso compound, a cyanine compound, a phthalocyanine compound or an anthraquinone compound, or a near infrared absorbing metal compound such as indium tin oxide or antimony tin oxide may be used alone or They can be used in combination. These near-infrared absorbing materials may be mixed with an adhesive, or may be used by mixing with a resin layer such as a transparent film.
The ultraviolet shielding layer can also be used to protect the dye used for the component of the front plate filter, particularly the color tone correction layer from the ultraviolet rays emitted from the PDP. As the ultraviolet absorber, an ultraviolet absorber that absorbs a short wavelength side of 420 nm or less can be used, and in particular, an ultraviolet absorber having a wavelength of 350 to 400 nm can be used. These may be mixed in a pressure-sensitive adhesive, or may be used by mixing in a resin layer such as a transparent film. In order to prevent the deterioration of the pigment due to external light, a plurality of layers can be installed as separate layers.

  The color tone correction layer and the contrast adjustment layer have a function of correcting and adjusting light transmitted through the front plate filter in the visible light region. It also has an adjustment function for neon orange light, which is an extra light emission color from the PDP. The contrast is adjusted so that the transmittance of the front plate filter in the visible light region is 70% or less. The color tone correction is adjusted so that the apparent color tone becomes a natural color tone in accordance with the light emission pattern from the PDP. These are made of pigments, and usually a plurality of pigments can be mixed and used in a resin layer such as an adhesive or a transparent film. As the pigment, organic pigments such as azo, phthalocyanine, anthraquinone, methine, pyrrole, and metal complex, dyes, and inorganic pigments can be used.

Among these, the near-infrared shielding layer, the ultraviolet shielding layer, the color tone correction layer, and the contrast adjustment layer may be provided independently of each other, but may be provided as several composite layers.
When external light (incident external light 9) is applied to the PDP display device, the light is partially reflected on the outer surface of the PDP front plate filter 1 to generate reflected light 10a. The external light 9 transmitted through the PDP front plate filter 1 is partially reflected on the inner surface of the PDP front plate filter 1 to generate reflected light 10b. The external light 9 transmitted through the PDP front plate filter 1 is partially reflected on the outer surface of the PDP 2 to generate reflected light 10c. The outside light 9 transmitted through the front glass 6 generates scattered light and regular reflection light 10 d inside the PDP 2. Here, when an antireflection film is provided on the outer surface of the PDP front plate filter 9, the reflected light 10a is reduced, but the reflected lights 10b to 10d are not reduced.

An example of the present invention is shown in FIG. A circularly polarizing plate 12 is provided on the inner surface of the PDP front plate filter 2 and an antireflection layer 11 is provided on the outer surface. The circularly polarizing plate is composed of a linearly polarizing plate 13 and a retardation plate 14.
The external light incident from the outside reduces the reflected light 10 a by the antireflection layer 11, and the external light 9 transmitted through the PDP front plate filter 1 is a P wave that is one component of the linearly polarized light component by the linearly polarizing plate 13. Only (or S wave) is transmitted. The P wave (or S wave) of the external light transmitted through the linear polarizing plate 13 is converted into circularly polarized light (for example, clockwise) by the phase difference plate 14. When this circularly polarized light (for example, clockwise) is reflected, the rotation direction is reversed, so that the reflected lights 10b to 10d pass through the phase difference plate 14 as reversely polarized circularly polarized light, and 90 It is converted into linearly polarized S wave (or P wave) having a different phase and absorbed without being transmitted through the linearly polarizing plate 13.

  Here, the circularly polarizing plate 12 needs to be provided inside the filter glass 4. When the circularly polarizing plate 12 is provided outside the filter glass 4 and inside or outside the functional film laminate 3, the circularly polarized light is disturbed by the filter glass or the functional film laminate 3 or 5. The reflected lights 10b to 10d were not sufficiently reduced. This is presumably because the circularly polarized light that passed through the circularly polarizing plate 12 was disturbed by the filter glass or the functional film laminate. Further, the circularly polarizing plate 12 needs to be provided inside the functional film laminate 5. When a circularly polarizing plate is provided between the filter glass 4 and the functional film laminate 4, the polarized light converted into circularly polarized light is disturbed by the functional membrane laminate 5 and the reduction of the reflected lights 10b to 10d is insufficient. . Therefore, in order to reduce the reflected light 10b-d from the outside without disturbing the polarization, a circularly polarizing plate is provided on the inner surface of the PDP front plate filter, and for the PDP to reduce the reflected light 10a. It is necessary to provide an antireflection layer on the outer surface of the front plate filter. In addition, a material that does not disturb circularly polarized light, such as an optical pressure-sensitive adhesive material or a TAC (triacetylcellulose) film, may be provided inside the circularly polarizing plate 12.

  The circularly polarizing plate 12 includes a linearly polarizing plate 13 and a retardation plate 14. These are provided in order of the linearly polarizing plate 13 and the phase difference plate 14 from the observer side (outside) to the inside. As the linear polarizing plate 13, a polarizing plate with a single polarizer may be used. However, for the purpose of handling, a linear polarizing plate 13 having a structure in which a TAC film or the like is laminated as a protective layer on one side or both sides may be used. The linearly polarizing plate is a transmission type linearly polarizing plate, and an iodine type or a dye type can be used. For example, linear polarizing plate NPF series manufactured by Nitto Denko Corporation, transmission type linear polarizing plate manufactured by Sanritz Co., Ltd., Sumikaran manufactured by Sumitomo Chemical Co., Ltd., iodine-based and dye-based polarizing plate manufactured by Polatechno Co., Ltd., LG Chemical For example, a polarizing plate manufactured by OPTIMAX, a polarizing plate manufactured by OPTIMAX, or the like can be used. As the linear polarizing plate, it is preferable that the orthogonal transmittance when the absorption axis of the linear polarizing plate is orthogonal is a maximum value of 3% or less at a wavelength of 400 nm to 700 nm. It is preferably used from the viewpoint.

  The retardation plate 14 is a quarter wavelength retardation plate of visible light wavelength. As the retardation plate, a polycarbonate, polysulfone, polyvinyl alcohol, polyarylate, or norbornene-based polymer film stretched and oriented can be used, and the retardation plate has a retardation difference of 1/4 wavelength of the visible light wavelength. Refractive film. A quarter phase plate with a wide band may be used. These may be a laminate of a plurality of birefringent films. Examples of retardation plates include JSR Arton Film, Teijin Chemicals Polycarbonate Film and Pure Ace WR, Nippon Zeon's Zeonore Film, Sekisui Chemical Co., Ltd. Essina, and a plurality of these retardation plates. Can be used.

As a circularly polarizing plate, the linearly polarizing plate and the retardation plate may be laminated directly using an adhesive or the like, and are interposed between them so long as they do not disturb polarization such as a protective film such as a TAC film. Also good. Moreover, you may use what is already laminated | stacked as a circularly-polarizing plate from each manufacturer. For example, what is provided as a circularly polarizing plate from polarizing plate manufacturers, such as Nitto Denko Corporation, Sanritz Co., Ltd., Polatechno Co., Ltd., Sumitomo Chemical Co., Ltd., can also be used.
A circularly polarizing plate may be elliptically polarized light instead of completely circularly polarized light. Also, the reflectance may increase somewhat depending on the wavelength of visible light. These imperfections can be measured by installing a circularly polarizing plate on the mirror surface and measuring the reflectance. In terms of the reflectance on the mirror surface, the reflectance at a wavelength of 550 nm is preferably 1% or less, and particularly preferably 0.5% or less, from the viewpoint of reducing reflected light when viewing the display. A circularly polarizing plate having a reflectance of 8% or less at wavelengths of 400 nm and 700 nm is preferable, and a circularly polarizing plate having a reflectance of 3% or less at wavelengths of 400 nm and 700 nm is particularly preferable. The characteristics of the circularly polarizing plate are adjusted to the wavelength and wavelength dependency with the minimum value in visible light by adjusting the transmissivity and wavelength dependency of the linear polarizing plate at right angles, the stretching ratio of the retardation plate and the laminated structure. can do.

  Since the circularly polarizing plate has a linearly polarizing plate in its configuration, the visible light transmittance is reduced to about 50%. For this reason, the light transmittance has been adjusted to 50 to 60% with a dye or the like for contrast adjustment so far, but partial shielding of visible light with a dye is not necessary when a circularly polarizing plate is used. Therefore, the color tone adjustment and the Ne cut adjustment are adjusted with a dye, and the entire PDP front plate filter is adjusted. Further, by using the circularly polarizing plate, the color of the front panel filter for PDP is tightened in black, and black is tightened as the PDP display device, and the color is also preferable. Visibility can be improved by reducing external light reflection, and the color is also useful because it is tightened in black.

In the present invention, an antireflection layer is provided on the outer surface of the front plate filter. As the antireflection layer, an antireflection layer having a visibility reflectance of 1.0% or less is preferably provided, and an antireflection layer having a visibility reflectance of 0.5% or less is particularly preferably provided. By providing an antireflection layer having such a visibility reflectance, external light reflection on the outermost surface can be greatly reduced, and visibility can be improved.
The antireflection layer includes an antireflection function by the interference of visible light (AR) and a method of increasing irregular reflection by suppressing regular reflection on the surface due to surface irregularities (AG). In this case, the screen becomes whitish in the PDP. Therefore, it is preferable to provide an antireflection function due to visible light interference, and the haze as a PDP front plate filter is preferably 10% or less, and particularly preferably 3% or less.

As an antireflection layer due to interference of visible light, one having a single layer or a multilayer structure is known. Among these, the multilayer structure by a dry process such as sputtering or vacuum deposition has the disadvantages that the optical characteristics are excellent, but the process is complicated and the productivity is low. In the present invention, a dry process may be used, but in view of industrial productivity, a wet process by coating is preferred. An antireflection film excellent in antireflection performance can be provided by a one-layer or two-layer structure using an antireflection film formed by a wet process.
As the configuration of the antireflection layer, a configuration of a low refractive index layer / high refractive index layer / hard coat / transparent substrate or a low refractive index layer / hard coat / transparent substrate is preferably used. The antireflection layer having such a configuration can be provided on the outer surface of the PDP front plate filter via an optical adhesive.

  As a transparent substrate, polyethylene film, polypropylene film, triacetyl cellulose, cellulose acetate film such as cellulose acetate propionate, stretched polyethylene terephthalate, polyester film such as polyethylene naphthalate, polycarbonate film, norbornene film, Polysulfone film, polyethersulfone film, polyarylate film and the like. Of these transparent substrates, a substrate having a refractive index of 1.45 to 1.55 is preferably used, and a TAC film (refractive index 1.49) is most preferably used. By reducing the refractive index difference between the functional film laminate, the filter glass, and the pressure-sensitive adhesive, it becomes easy to reduce the reflectance.

The thickness of the transparent substrate is preferably 25 μm or more from the viewpoint of the uniformity of the thickness of the low refractive index layer and the handleability as an optical substrate. A preferred upper limit is 200 μm from the viewpoint of light transmittance and light utilization efficiency.
It is preferable to provide a hard coat layer on the transparent substrate. By providing the hard coat layer, the surface layer of the PDP front plate filter can be strengthened, and it can be made hard to be damaged. As the hard coat, those having a pencil strength of H or higher in the pencil hardness test according to JISK5400 are preferably used, and those having a hardness of 2H or higher are particularly preferably used.
Typical materials for the hard coat are melamine, acryl radical, acryl silicone, and alkoxy silane, and organic and / or inorganic fine particles dispersed in the hard coat material as a matrix (hereinafter referred to as organic). (It is also possible to use an inorganic particle dispersion system).

Among the above hard coat materials, the acrylic radical system is preferably a polymer obtained by polymerizing a polyfunctional acrylate oligomer and / or a polyfunctional acrylate monomer. Examples of the polyfunctional acrylate monomer include dipentaerythritol hexaacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and ditrimethylolpropane tetraacrylate.
Polyfunctional acrylate oligomers include epoxy acrylates that are acrylate-modified novolak-type and bisphenol-type epoxy resins, urethane acrylates that are acrylate-modified products of urethane compounds obtained by reacting polyisocyanates and polyols, and polyester acrylates that are acrylate-modified polyester resins. Etc.

Moreover, in the acrylic silicone type | system | group, what bonded the acrylic group by the covalent bond on the silicone resin is preferable.
Moreover, in the alkoxysilane type | system | group, what contains the condensate which has the silanol group obtained by carrying out the hydrolysis polycondensation of alkoxysilane is preferable. A silanol group is converted into a siloxane bond by thermosetting after coating, and a cured film is obtained.
The hard coat layer is preferably a hard coat material capable of performing heat curing, ultraviolet curing, and electron beam curing. The hard coat material preferably contains a photopolymerization initiator, a thermal polymerization initiator, an additive, a solvent and the like depending on the curing method.

  Examples of inorganic particles used in the organic / inorganic particle dispersion include silicon dioxide particles, titanium dioxide particles, aluminum oxide particles, zirconium oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc, kaolin and sulfuric acid. A calcium particle is mentioned. Examples of organic particles include methacrylic acid-methyl acrylate copolymer, silicone resin, polystyrene, polycarbonate, acrylic acid-styrene copolymer, benzoguanamine resin, melamine resin, polyolefin, polyester, polyamide, polyimide and polyfluorinated ethylene. The average particle diameter of these particles is preferably 0.01 to 5 μm, and more preferably 0.01 to 0.3 μm. A plurality of organic particles and inorganic particles may be mixed and used, or a mixture of organic particles and inorganic particles may be used.

The organic particles and inorganic particles that can be used in the present invention may or may not be chemically bonded to the hard coat material used as a matrix. The organic / inorganic particle-dispersed hard coat material has a function of increasing the hardness of the hard coat layer and suppressing curing shrinkage by dispersing the particles in the hard coat material.
Specific examples of the inorganic particle dispersion system include an acrylic radical system in which inorganic fine particles are dispersed, an organic polymer system in which inorganic fine particles are dispersed, an organoalkoxysilane system in which inorganic fine particles are dispersed, and the like. What disperse | distributed silica, titanium oxide, an alumina, etc. is preferable. Further, it is also preferable to use fine particles in which the surface of the silica particles is modified with an acryloyl group.
In addition to the hard coat layer, colorants (pigments, dyes), antifoaming agents, thickeners, leveling agents, flame retardants, UV absorbers, antistatic agents, antioxidants and modifying resins are added. Also good.

As the antistatic agent, those obtained by dispersing a known antistatic agent such as a surfactant or an ionic polymer or conductive fine particles in a binder are used. Examples of the conductive fine particles include oxide or composite oxide fine particles such as indium, zinc, tin, molybdenum, antimony, and gallium, copper, silver, nickel, low melting point alloy (solder, etc.) metal fine particles, and a metal-coated polymer. Known materials such as fine particles, various kinds of carbon black, conductive polymer particles such as polypyrrole and polyaniline, metal fibers, and carbon fibers can be used. Among these, ITO (tin-containing indium oxide) particles, ATO (tin-containing antimony oxide) particles, and antimony pentoxide particles are particularly preferable because they can exhibit high transparency and conductivity.
It is also preferable when the hard coat layer is surface-modified. The surface modification treatment is preferably treatment using corona treatment, deep-UV irradiation, excimer lamp irradiation, vacuum plasma treatment, atmospheric pressure plasma treatment, electron beam irradiation, primer treatment containing a silane coupling agent, or the like.

  For coating the hard coat layer, a composition obtained by adding additives as necessary to the above hard coat material is applied on a transparent plastic substrate as a coating solution using a solvent as necessary, and is formed and cured. Can be manufactured. Solvents include water, methanol, ethanol, isopropanol, butanol, benzyl alcohol and other alcohols, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and other ketones, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, Esters such as ethyl formate, propyl formate and butyl formate, aliphatic hydrocarbons such as hexane and cyclohexane, halogenated hydrocarbons such as methylene chloride, chloroform and carbon tetrachloride, and aromatic carbonization such as benzene, toluene and xylene Hydrogens, amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, diethyl ether, dioxane, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol dimethyl Ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, solvent ethers such as propylene glycol dimethyl ether, preferably toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol.

The hard coat layer can be obtained by coating and drying and then heating and curing at 80 to 150 ° C. or curing using light or an electron beam.
The hard coat material that can be used in the present invention has been described above, but as the hard coat material that can be used in the present invention, a commercially available silicone hard coat, (meth) acrylic hard coat, epoxy hard coat, Known materials such as urethane hard coat, epoxy acrylate hard coat, and urethane acrylate hard coat can be used. Specifically, Shin-Etsu Chemical Co., Ltd. UV curable silicone hard coat agent X-12 series, GE Toshiba Silicone Co., Ltd. UV curable silicone hard coat agent UVHC series, thermosetting silicone hard coat agent SHC series, stock A thermosetting silicone hard coat agent Solguard NP series manufactured by Nippon Dacro Shamrock Co., Ltd. and a UV curable hard coat agent KAYANOVA FOP series manufactured by Nippon Kayaku Co., Ltd. are preferred. In addition, it can be formed by applying a coating liquid containing a polyfunctional monomer and a polymerization initiator and polymerizing the polyfunctional monomer. The thickness of the hard coat layer is usually set to 0.1 μm to 5 μm.

  Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.

  When a transparent base material having a refractive index of 1.45 to 1.55 is used and a low refractive index layer / hard coat / transparent base material is used, the hard coat has a refractive index of 1. It is preferable to set it to 45-1.58. In this configuration, it is preferable to provide the hard coat with an antistatic function. By mixing the conductive fine particles and the low refractive index fine particles, the antistatic function and the refractive index can be adjusted, and the pencil strength can be 2H or more. On the other hand, when the low refractive index layer / high refractive index layer / hard coat / transparent substrate is used, the refractive index of the hard coat layer is preferably adjusted to 1.50 to 1.60 from the viewpoint of reflectivity. . In the case of this configuration, an antistatic function can be imparted to the high refractive index layer.

The low refractive index layer is preferably adjusted to have a refractive index of 1.20 to 1.40, particularly 1.20 to 1.35. Since it has such a refractive index, the visibility reflectance can be reduced, and the transfer of external light on the surface layer can be greatly reduced.
Such a low refractive index layer preferably has a refractive index of 1.53 or less as a binder. A binder having a low refractive index is useful for lowering the refractive index. In addition, it is preferable to mix low refractive index fine particles such as hollow silica fine particles. By mixing the refractive index of the binder and the low refractive index fine particles such as hollow silica fine particles, the refractive index of the low refractive index layer can be adjusted.
The hollow silica fine particles are fine particles having cavities therein, and the hollow silica fine particles themselves have a low refractive index (for example, refractive index = 1.10 to 1.35). Since the cavity is surrounded by the outer shell, the binder does not enter the cavity. The presence of this cavity can reduce the refractive index, and the blocking of the binder from entering the cavity can prevent an increase in the refractive index. A function as a prevention film can be realized.

Specifically, it is preferable to use hollow silica fine particles having a refractive index of 1.10 to 1.35 and an average particle size of 30 to 300 nm, particularly 40 to 200 nm. The refractive index of the hollow silica fine particles is preferably 1.10 or more from the viewpoint of the strength of the particles themselves. The refractive index is preferably 1.35 or less, more preferably 1.30 or less, and most preferably 1.26 or less from the viewpoint of obtaining sufficient antireflection performance. The refractive index of the hollow silica fine particles can be adjusted by the void ratio of the cavity, and can be adjusted by the thickness of the outer shell and the particle size.
The outer diameter (average particle diameter) of the hollow silica fine particles is preferably 30 nm or more from the viewpoints of dispersibility, surface properties of the resulting layer, antireflection performance, and strength. The upper limit of the outer diameter of the hollow silica fine particles is preferably 200 nm or less from the viewpoints of antireflection performance, resolution of the fluoroscopic image, and visibility.

The binder for the low refractive index layer may be used alone or in combination. Preferred binders include the following.
(1) Tetramethoxysilane, tetraethoxysilane, tetra (i-propoxy) silane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxy Silane, propyltriethoxysilane, isobutyltriethoxysilane, methyltri-iso-propoxysilane, ethyltri-iso-propoxysilane, dimethoxysilane, diethoxysilane, methyldimethoxysilane, methyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane Diethyldimethoxysilane, diethyldiethoxysilane, diethyldi (i-propoxy) silane, methylethyldimethoxysilane, methylethyldiethoxysilane , Methylethyldi (i-propoxy) silane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, methylpropyldi (i-propoxy) silane, methoxysilane, ethoxysilane, methylmethoxysilane, methylethoxysilane, dimethylmethoxysilane, dimethyl Ethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethyl (i-propoxy) silane, triethylmethoxysilane, triethylethoxysilane, triethyl (i-propoxy) silane, tripropylmethoxysilane, tripropylethoxysilane, tripropyl (i- Propoxy) silane, methyldiethylmethoxysilane, methyldiethylethoxysilane, methyldiethyl (i-propoxy) silane, methyldipropylmeth Sisilane, methyldipropylethoxysilane, methyldipropyl (i-propoxy) silane, ethyldimethylethoxysilane, ethyldimethyl (i-propoxy) silane, ethyldipropylmethoxysilane, ethyldipropylethoxysilane, ethyldipropyl (i- Propoxy) silane, propyldimethylmethoxysilane, propyldimethylethoxysilane, propyldimethyl (i-propoxy) silane, propyldiethylmethoxysilane, propyldiethylethoxysilane, propyldiethyl (i-propoxy) silane, bis (trimethoxysilyl) methane, Bis (triethoxysilyl) methane, bis (trimethoxysilyl) ethane, bis (triethoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,3-bis ( Triethoxysilyl) propane, hexamethoxydisiloxane, hexaethoxydisiloxane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Mercaptopropyltriethoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltri Ethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, tetraacetoxysilane, tetrakis (trichloroacetoxy) silane, tetrakis (trifluoroacetate) Xyl) silane, triacetoxysilane, tris (trichloroacetoxy) silane, tris (trifluoroacetoxy) silane, methyltriacetoxysilane, methyltris (trichloroacetoxy) silane, methyltris (trifluoroacetoxy) silane, methyldiacetoxysilane, methylbis ( Trichloroacetoxy) silane, methylbis (trifluoroacetoxy) silane, dimethylbis (trichloroacetoxy) silane, dimethylbis (trifluoroacetoxy) silane, methylacetoxysilane, methyl (trichloroacetoxy) silane, methyl (trifluoroacetoxy) silane, dimethyl Acetoxysilane, dimethyl (trichloroacetoxy) silane, dimethyl (trifluoroacetoxy) silane, trimethylacetoxy Run, trimethyl (trichloroacetoxy) silane, trimethyl (trifluoroacetoxy) silane, tetrachlorosilane, tetrabromosilane, tetrafluorosilane, trichlorosilane, tribromosilane, trifluorosilane, methyltrichlorosilane, methyltribromosilane, methyltri Fluorosilane, methyldichlorosilane, methyldibromosilane, methyldifluorosilane, dimethyldichlorosilane, dimethyldibromosilane, dimethyldifluorosilane, methylchlorosilane, methylbromosilane, methylfluorosilane, dimethylchlorosilane, dimethylbromosilane, dimethylfluorosilane, trimethyl Reacted with hydrolyzable silanes such as chlorosilane, trimethylbromosilane, trimethylfluorosilane It is. In the case of using hollow silica fine particles, the reaction is preferably carried out by dehydration condensation after the reaction.

(2) 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriacetoxysilane, 3-acryloxypropyltris (trichloroacetoxy) silane, 3-acryloxypropyltris (trifluoroacetoxy) silane, 3-methacryloxypropyltriacetoxy Silane, 3-methacryloxypropyltris (trichloroacetoxy) silane, 3-methacryloxypropyltris (trifluoroacetoxy) silane, 3-glycidoxypropyltriacetoxysila 3-glycidoxypropyltris (trichloroacetoxy) silane, 3-glycidoxypropyltris (trifluoroacetoxy) silane, 3-acryloxypropyltrichlorosilane, 3-acryloxypropyltribromosilane, 3-acryloxypropyl Trifluorosilane, 3-methacryloxypropyltrichlorosilane, 3-methacryloxypropyltribromosilane, 3-methacryloxypropyltrifluorosilane, 3-glycidoxypropyltrichlorosilane, 3-glycidoxypropyltribromosilane, Reactive silanes having both a polymerizable functional group and a functional group capable of forming a covalent bond with silica particles in the same molecule, such as 3-glycidoxypropyl trifluorosilane, and these were reacted Things . In the reaction, the polymerizable functional group portion can be polymerized after covalently bonding them with inorganic fine particles such as hollow silica fine particles.

(3) Silicic acid, trimethylsilanol, triphenylsilanol, dimethylsilanediol, diphenylsilanediol, silanol terminated polydimethylsiloxane, silanol terminated polydiphenylsiloxane, silanol terminated polymethylphenylsiloxane, silanol terminated polymethyl ladder siloxane, silanol terminated poly Silicon compounds containing silanol groups such as phenyl ladder siloxane and octahydroxy octasilsesquioxane.

(4) Water glass, sodium orthosilicate, potassium orthosilicate, lithium orthosilicate, sodium metasilicate, potassium metasilicate, lithium metasilicate, tetramethylammonium orthosilicate, tetrapropylammonium orthosilicate, tetramethylammonium metasilicate, metasilicate Active silica obtained by bringing a silicate such as tetrapropylammonium into contact with an acid or ion exchange resin.

(5) Polyethers such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, polyacrylamide derivatives, polymethacrylamide derivatives, amides such as poly (N-vinylpyrrolidone) and poly (N-acylethyleneimine), polyvinyl Organic polymers such as alcohols, polyvinyl acetate, polyacrylic acid derivatives, polymethacrylic acid derivatives, esters such as polycaprolactone, polyimides, polyurethanes, polyureas, and polycarbonates. These organic polymers may have a polymerizable functional group at the terminal or main chain.

(6) alkyl (meth) acrylate, alkylene bis (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Polymerized acrylic monomers such as dipentaerythritol hexa (meth) acrylate. Polymerizable monomers such as alkylene bisglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, pentaerythritol tetraglycidyl ether, vinylcyclohexene diepoxide. Here, (meth) acrylate refers to both acrylate and methacrylate. These are polymers.

(7) A known curable resin. For example, (meth) acrylic UV curable resin, moisture curable silicone resin, thermosetting silicone resin, epoxy resin, phenoxy resin, novolac resin, silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin , Polyimide resin, urethane resin, urea resin and the like.
(8) The alkyl groups and hydrogen groups in the above (1) to (7) can be substituted with fluorine. Those substituted with fluorine have a low refractive index and excellent optical performance. However, since it may be mechanically weak alone, it can be used by mixing with inorganic fine particles.

The binder may be used alone or in combination. In particular, reactive silanes having both a polymerizable functional group and a functional group capable of forming a covalent bond with a silica particle in the same molecule listed in (2) are used in combination, or listed in (6). Use of a polymerizable monomer in combination is effective in improving mechanical strength.
The kind of the polymerizable monomer is appropriately selected according to the form and speed of the reaction. When using a polymerizable monomer or one having a functional group, it is effective to add a polymerization initiator as an additive. As the polymerization initiator, a known one such as a thermal radical generator, a photo radical generator, a thermal acid generator, or a photo acid generator can be selected according to the reaction mode of the above polymerizable functional group or polymerizable monomer. it can.

  Specific examples of the heat / photo radical generator include Irgacure (registered trademark) and Darocur (registered trademark) acetophenone-based, benzophenone-based, phosphine oxide-based, and titanocene-based commercially available from Ciba Specialty Chemicals Co., Ltd. Each polymerization initiator, a thioxanthone polymerization initiator, a diazo polymerization initiator, an o-acyloxime polymerization initiator, and the like can be mentioned. Among these, polymerization initiators having an amino group and / or a morpholino group in the molecule such as Irgacure (registered trademark) 907, Irgacure (registered trademark) 369, and Irgacure (registered trademark) 379 are particularly preferable. Specific examples of the heat / photoacid generator include Sun Aid (trademark) SI series commercially available from Sanshin Chemical Industry Co., Ltd., WPI series, WPAG series, and Sigma Aldrich commercially available from Wako Pure Chemical Industries, Ltd. Examples thereof include sulfonium-based, iodonium-based, and diazomethane-based polymerization initiators represented by the PAGs series marketed by Japan Corporation.

  The silanes represented by (1) and (2) are preferably used after partial hydrolysis / dehydration condensation. Partial hydrolysis and dehydration condensation reactions are carried out by reacting hydrolyzable silane with water, but as catalysts, acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, formic acid, acetic acid, ammonia, trialkylamine Alkalis such as sodium hydroxide, potassium hydroxide, choline and tetraalkylammonium hydroxide, and tin compounds such as dibutyltin dilaurate may be used. In that case, when using inorganic particles such as hollow silica fine particles, it is preferable to perform a hydrolysis / dehydration condensation reaction in the presence of these inorganic particles. By performing hydrolysis in the presence of the inorganic particles in this way, it is possible to surely create many covalent bonds with the inorganic particles, and the mechanical strength of the low refractive index layer can be improved.

The thickness of the low refractive index layer is usually 50 to 200 nm, more preferably 50 to 150 nm, from the viewpoint of antireflection performance in the visible light region. Also, the color of the antireflection film can be controlled by controlling the thickness.
The method for producing the low refractive index layer is not limited, and when coated on an optical substrate using the coating composition, the content of inorganic particles such as hollow silica fine particles, the concentration of the coating liquid, the types of binders and additives And it can manufacture by controlling those density | concentrations, the coating method, a coating condition, etc.
Application of the coating composition is a known dipping, spin coater, knife coater, bar coater, blade coater, squeeze coater, reverse roll coater, gravure roll coater, slide coater, curtain coater, spray coater, die coater, cap coater, etc. It can be implemented using a method. Of these, knife coaters, bar coaters, blade coaters, squeeze coaters, reverse roll coaters, gravure roll coaters, slide coaters, curtain coaters, spray coaters, die coaters and cap coaters that can be continuously applied are preferably used.

After applying the above coating composition, it is effective to heat in order to volatilize the dispersion medium and to condense and crosslink between the silica particles and the binder component. The heating temperature and time are determined by the heat resistance of the substrate. For example, when a plastic substrate is used as the optical substrate, the heating temperature is selected from 50 ° C. to 200 ° C., and the time is selected from 1 second to 1 hour, preferably in the range of 80 ° C. to 150 ° C., 10 seconds to 3 minutes. It is. Moreover, when the said binder has radiation curability, an ultraviolet-ray, an electron beam, etc. are irradiated by a well-known method.
The low refractive index layer can contain various additives such as an antistatic agent, an ultraviolet absorber, an infrared absorber, a leveling agent, a dye, a metal salt, a surfactant, and a release agent.

  A coating layer may be provided for imparting slipperiness or antifouling property to the surface of the antireflection film. The coating layer is, for example, a fluororesin, a moisture curable silicone resin, a thermosetting silicone resin, silicon dioxide, a (meth) acrylic resin, a (meth) acrylic UV curable resin, an epoxy resin, a phenoxy resin, a novolac resin, It is made of any known material such as silicone acrylate resin, melamine resin, phenol resin, unsaturated polyester resin, polyimide resin, urethane resin, urea resin. The film thickness of the coating layer is usually 50 nm or less, preferably 10 nm or less, more preferably 1 nm or more and 5 nm or less. The coating layer may be composed of a single layer or a plurality of layers. Among these, a fluororesin, a moisture curable silicone resin, and a thermosetting silicone resin are preferable in order to exhibit an antifouling effect.

  It is also possible to provide a high refractive index layer immediately below the low refractive index layer. As the high refractive index layer, for example, known inorganic fine particles such as oxides or composite oxides of metals such as titanium, zirconium, zinc, antimony, indium, tin, cerium, tantalum, yttrium, hafnium, aluminum, and magnesium are used. The one dispersed in is used. As the binder, those listed in the above (1) to (8) can be used as the binder for the low refractive index layer. Among them, the organic polymer described in (5) is preferably polymerized on the side chain or the terminal. A polymerizable monomer described in (6), and a curable resin described in (7). As the kind and amount of these binders, known ones can be used depending on the desired refractive index, strength, light resistance, yellowing and the like. The refractive index of the high refractive index layer is preferably 1.55 to 1.68 in terms of antireflection performance, and particularly preferably 1.57 to 1.65. The thickness of the high refractive index layer is preferably 50 to 300 nm, particularly preferably 120 to 180 nm. By controlling the thickness, it is possible to control the reflectance and the color of the antireflection film.

  As described above, the PDP front plate filter is provided with the circularly polarizing plate and the antireflection film in a specific configuration. The PDP display device provided with this PDP front plate filter has reduced visibility of external light and improved visibility. Further, the black color is also good, and it is useful as a PDP display device.

[Various measurement methods]
(1) Measurement of the reflectance of the antireflection film; an antireflection film comprising a transparent substrate / hard coat / (high refractive index layer) / low refractive index layer is attached to a glass plate with an acrylic optical adhesive, and glass In order to cut off the reflected light on the back side of the plate (the side without the low refractive index layer), the back side was roughed with sandpaper and then painted with black ink. Then, using a spectrophotometer UV-2450 / MPC2200 type 5 ° absolute reflectance measuring device (manufactured by Shimadzu Corporation), the reflectance spectrum in the wavelength range of 300 nm to 800 nm was measured at intervals of 0.5 nm.
For the visibility reflectance, the visibility reflectance for the D65 light source defined in JIS Z8720 was calculated from the measured reflectance spectrum.
Further, from the measured reflectance spectrum, chromaticity coordinates xy of the XYZ color system defined in JIS Z8722 as a reflected color were calculated.

(2) Measurement of haze: Measured by a method defined in JIS K7361-1 using a turbidimeter (cloudiness meter) NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.
(3) Reflectance measurement on the mirror surface: Install the circularly polarizing plate on the retardation plate side of the total reflection mirror (aluminum flat mirror), and use a spacer so that an air layer exists between the retardation plate and the total reflection mirror. Space was secured. A visible polarizing filter (for 400 to 700 nm) was installed on the incident light side of the spectrophotometer UV-2450 / MPC2200 type 5 ° absolute reflectance measuring device (manufactured by Shimadzu Corporation), and the incident light was converted into a linear change. . Since the incident light of the reflectance measuring device is not completely random light, it was measured by converting it into linearly polarized light for accurate measurement. The converted linearly polarized light was applied to the linearly polarizing plate side of the circularly polarizing plate, and the reflectance spectrum was measured at intervals of 0.5 nm in the wavelength range of 400 to 700 nm.
The measurement was performed by measuring the reflectance spectrum of the linearly polarized light of the incident light and the transmission axis of the linearly polarizing plate of the circularly polarizing plate from 0 ° to 180 ° at intervals of 5 °. As a result, it was found that the 45 ° reflectance spectrum was an average spectrum of the reflectance spectrum of 0 to 180 °.
In the data processing, the reflectance spectrum (minimum reflectance) when the linearly polarized light of the incident light and the transmission axis of the linearly polarized light of the circularly polarizing plate are orthogonal to each other is blank, and an angle of 45 ° is formed from this orthogonal state. The reflectance on the mirror surface was obtained by subtracting the reflectance spectrum of the blank (the spectrum at the time of orthogonality) from the reflectance spectrum.
Here, the reflectance spectrum in the orthogonal state substantially represents reflection on the surface of the circularly polarizing plate.

(4) Refractive index estimation method: Samples are coated on a known sheet in various thicknesses, and the reflectance of 300 nm to 800 nm is measured using an FE3000 reflection spectrometer (manufactured by Otsuka Electronics Co., Ltd.). The refractive index of the sample was estimated by simulation, which is software attached to FE3000.
(5) Measurement of surface resistivity; using a superinsulator SM-8210 manufactured by Toa DKK Corporation as a measuring device and a plate sample electrode SME-8311 as an electrode, the surface resistivity was measured by a method prescribed in JIS K6911. . (20 ° C, 65RH%)

[Example 1]
As the circularly polarizing plate A, a circularly polarizing plate using a polycarbonate film as a retardation plate was used. When the reflectance on the mirror surface was measured, the reflectances at wavelengths of 400 nm, 550 nm, and 700 nm were 2.6%, 0.6%, and 6.7%, respectively.
Preparation of antireflection layer A: As a transparent substrate, a TAC film (80 μm thick) TDY80UL containing a UV absorber manufactured by Fuji Photo Film Co., Ltd. was used. Using KD200M manufactured by Nippon Kayaku Co., Ltd. as a hard coat, it was applied and cured to a thickness of 3 μm on the TAC film. As a high refractive index layer, ITO particles as conductive fine particles were dispersed in DPHA (dipentaerythritol hexaacrylate), and a layer having a refractive index of 1.62 having an antistatic function and a thickness of about 130 nm was applied and cured. As the low refractive index layer, TU2085 manufactured by JSR Co., Ltd., hollow silica fine particles (average diameter 60 nm, outer shell thickness of about 7 nm, refractive index 1.25) are used as the binder, and the refractive index is 1.33 and the thickness is 80 to 90 nm. The layer of was coated and cured.

When the obtained antireflection layer was attached to glass using an adhesive LS0280 manufactured by Lintec Co., Ltd., and the back surface treatment was performed to measure the reflectance, the minimum reflectance was at a wavelength of 535 nm, and the minimum reflectance was 0.2. %, The visibility reflectance was 0.3%, and the chromaticity coordinates (x, y) of the reflected light were (0.31, 0.24). The surface resistivity was 10 ¹⁵ Ω / □.
The antireflection layer A was stuck on the outer surface of the front plate filter of the PDP display device having the front plate filter using the adhesive LS0280. On the other hand, a circularly polarizing plate was attached to the inner surface with a pressure-sensitive adhesive so that the linearly polarizing surface was on the functional film laminate such as a copper mesh layer. The direction of attachment was such that the absorption axis of the linearly polarizing plate was vertical.

A PDP display device was assembled such that the front plate filter on which the antireflection film and the circularly polarizing plate were bonded was placed inside the circularly polarizing plate.
A diffuser plate with a thickness of 3 mm was installed on the front surface of a daylight white (3-wave tube) fluorescent lamp stand, and a cover was installed with a black plastic plate to provide a 40 mm square window. The luminance of the light source within a 40 mm square was about 5000 cd / m ² due to the diffusion plate.
This light source was installed at a position 20 cm from the surface of the PDP display device, and the appearance of the reflected light source was observed. The results are summarized in Table 1.
Next, a digital television signal generator DPG-300 manufactured by “PC ByeOS Kobo” was connected to the D terminal of the PDP display device, various pattern signals were input, and the state of the image was evaluated. The results are summarized in Table 1.

[Example 2]
As the circularly polarizing plate B, RD-HL56-W03 manufactured by Sanritz Corporation was used. When the specular reflectance was measured, the reflectances at wavelengths of 400 nm, 550 nm, and 700 nm were 1.2%, 0.2%, and 1.8%, respectively. The reflection was evaluated in the same manner as in Example 1 except that this polarizing plate was attached to the front plate filter in the same manner as in Example 1. Moreover, various pattern signals were input with DPG-300, and the image state was evaluated. These results are summarized in Table 1.

[Comparative Example 1]
As in Example 1, the circularly polarizing plate B was pasted via an adhesive layer so that the antireflection layer was not pasted on the outer surface of the front plate filter, and the inner surface was a retardation plate. The direction of attachment was such that the absorption axis of the linearly polarizing plate was vertical. Further, an antireflection layer A was attached to the outside of the circularly polarizing plate B using an adhesive. The configuration of the front plate filter was copper mesh layer / glass / circularly polarizing plate / antireflection layer, and the PDP display device was assembled so that this copper mesh layer was on the inside.
In the same manner as in Example 1, the evaluation of the reflection and the image state with the pattern signal were evaluated. These results are summarized in Table 1.

[Comparative Example 2]
In Comparative Example 1, the antireflection layer A was not applied, and the circularly polarizing plate was made to be the outer surface. This evaluation was performed in the same manner as in Example 1 to evaluate the reflection and the image state with the pattern signal. These results are summarized in Table 1.

[Comparative Example 3]
In Comparative Example 1, the circularly polarizing plate B was not pasted, and only the antireflection layer A was the outer surface. This evaluation was performed in the same manner as in Example 1 to evaluate the reflection and the image state with the pattern signal. These results are summarized in Table 1.

  The front plate filter for PDP of the present invention is useful for a PDP display device because reflection can be reduced and the visibility of the screen is improved. A display device using the same is excellent in visibility.

Schematic diagram of conventional PDP and PDP front plate filter Schematic which shows an example which provided PDP and the front plate filter for PDP of this invention.

Explanation of symbols

1: Front plate filter for PDP 2: PDP
3: functional film laminate 4: filter glass 5: functional film laminate 6: front glass 7: plasma emission region 8: back glass 9: incident external light 10a to d: reflected external light 11: antireflection layer 12 : Circularly polarizing plate 13: Linearly polarizing plate 14: Retardation plate

Claims (4)

  A front plate filter for a plasma display panel, characterized in that a circularly polarizing plate is provided on the inner surface of the filter, and an antireflection layer is provided on the outer surface of the front plate filter. filter.   The front plate filter for a plasma display panel according to claim 1, wherein an antireflection layer having a visibility reflectance of 1% or less is provided.   A circularly polarizing plate having a reflectance on a mirror surface in a visible light region of a circularly polarizing plate, a reflectance at a wavelength of 550 nm of 1% or less, and a reflectance at wavelengths of 400 nm and 700 nm of 8% or less is used. The front filter for a plasma display panel according to claim 1 or 2.   A plasma display panel display device comprising the front panel filter for a plasma display panel according to claim 1.

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