JP2008070708A - Antireflection / near infrared ray shielding filter, optical filter for plasma display panel using the same and plasma display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection / near IR (infrared ray) shielding filter which can be simply manufactured, has an excellent antireflection property and a near IR shielding property, produces nearly no interference fringe and has improved durability too. <P>SOLUTION: An intermediate layer 12, a hard coat layer 13 and a low refractive index layer 14 having a refractive index lower than that of the hard coat layer 13 are provided in this order and further a near IR absorbing layer 15 is provided on another surface of a transparent base material to form the antireflection / near IR shielding filter. Following formulas (1) to (4) are satisfied and one or more sorts of dyestuffs contained in the near IR absorbing layer 15 have absorption maximums in a wavelength range between 800 and 1200 nm and in a wavelength range between 580 and 605 nm. (1) n<SB>1</SB>>n<SB>2</SB>>n<SB>3</SB>, (2) ¾ n<SB>2</SB>-(n<SB>1</SB>+n<SB>3</SB>)/2 ¾≤ 0.07, (3) 1.56≤n<SB>1</SB>≤1.71, (4) 1.50≤n<SB>2</SB>≤1.70, wherein n<SB>1</SB>is a refractive index of the transparent base material, n<SB>2</SB>is a refractive index of the intermediate layer and n<SB>3</SB>is a refractive index of the hard coat layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical filter having various functions such as antireflection and near-infrared shielding for a plasma display panel (PDP), and a plasma display panel including the optical filter.

  Usually, a front filter is always used for a PDP. This front filter is intended for cutting near infrared rays, improving color reproducibility (emission color purity improvement), electromagnetic wave shielding, improving contrast in a bright place (antireflection), protecting a light emitting panel, blocking heat from the light emitting panel, and the like.

  It is necessary to reduce the near infrared rays emitted from the light emitting panel of the PDP in order to avoid malfunctioning the remote control used for home television and video. In addition, it is necessary to reduce the electromagnetic waves emitted by the light emitting panel of the PDP in order to avoid adverse effects on the human body and precision equipment. Further, in order to make the light emitted from the light emitting panel of the PDP feel a natural color for human vision, there is a demand for improvement in color reproducibility (light emission color purity improvement) by correction with a filter. Furthermore, it is desirable that the display on the display be visually recognized with sufficient contrast without being hindered by reflection of light from the outside even in a bright place such as a bright room. In addition, even when the display product is directly touched by hand, it is desirable that the heat generated by the light emitting panel of the PDP is cut off in order to avoid a situation where the user is surprised by the high temperature.

  In general, optical filters having various functions such as antireflection, near-infrared shielding, and electromagnetic wave shielding are used as typical PDP optical filters that meet the above-mentioned purpose. However, in actuality, it is used as an optical filter for PDP by bonding optical filters having respective functions and optical filters having two functions in an appropriate combination.

  For example, as an optical filter having antireflection and near infrared blocking functions, Patent Document 1 (Japanese Patent Laid-Open No. 2005-189738) discloses a surface layer (A) having an antireflection function, a base film (B), and a near infrared ray. The absorption layer (C) is sequentially laminated, and the near-infrared absorption layer (C) contains a dye having a maximum absorption in a near-infrared absorption region having a wavelength of 800 to 1000 nm, and a surfactant having an HLB of 2 to 12. A near infrared absorption filter is disclosed. The surface layer (A) having an antireflection function, that is, the antireflection layer has a three-layer structure in which a hard coat layer, a high refractive index layer, and a low refractive index layer are laminated in this order. Examples of the hard coat layer include a photocurable resin layer, and examples of the low refractive index layer and the high refractive index layer include a coating layer and a vapor deposition layer.

JP 2005-189738 A

  Naturally, an optical filter for a plasma display panel having functions of preventing reflection and blocking near infrared rays is required to have a particularly simple structure and excellent both functions. For this purpose, the antireflection layer, the near-infrared absorbing layer, the transparent substrate, and the transparent pressure-sensitive adhesive layer must be integrated while complementing each other and exhibit an excellent function. Although the optical filter described in Patent Document 1 is specified for the near-infrared absorbing layer, detailed consideration is given to the relationship between the refractive indexes of other configurations such as a transparent substrate, an intermediate layer, and a hard coat layer. Therefore, it cannot be said that the antireflection property, the near infrared ray blocking property, and the durability are sufficient.

  According to the study of the present inventor, the near-infrared absorption layer is achieved by using a dye having an absorption maximum in the wavelength range of 800 to 1200 nm and the wavelength range of 580 to 605 nm, thereby achieving blocking of the near infrared light with a low concentration of dye. I found it easy to do. However, other properties (reflection properties, durability, etc.) may deteriorate depending on the relationship between the refractive index and layer thickness of the transparent substrate, intermediate layer, and hard coat layer. It has become clear that it is necessary to design layers and substrates other than the near-infrared absorbing layer so as not to deteriorate other characteristics while maintaining the above.

  Therefore, the object of the present invention is to provide an antireflection film for use in an optical filter for a plasma display panel, which can be easily manufactured, has excellent antireflection properties and near-infrared shielding properties, and has almost no generation of interference fringes. The object is to provide a near-infrared shielding filter.

  Another object of the present invention is for a plasma display panel, which can be easily manufactured, has excellent antireflection properties and near-infrared shielding properties, hardly generates interference fringes, and has improved durability. An object of the present invention is to provide an antireflection / near-infrared cutoff filter used for an optical filter.

Furthermore, the object of the present invention is to produce an image that can be easily manufactured, has an excellent antireflection property and a near-infrared blocking property, has almost no interference fringes, and has a good contrast when mounted on a PDP. Another object of the present invention is to provide an antireflection / near-infrared blocking filter used for an optical filter for a plasma display panel, which can be provided and improved in durability. Also, an object of the present invention is to provide a plasma display panel having the above characteristics. Another object is to provide an optical filter for use.

  A further object of the present invention is to provide a plasma display panel with an optical filter for a plasma display panel having the above characteristics.

The present inventors have stated that the above purpose is
A low refractive index layer having a refractive index lower than that of the intermediate layer, the hard coat layer, and the hard coat layer is provided in this order on one surface of the transparent substrate, and a near-infrared absorbing layer is provided on the other surface of the transparent substrate. An anti-reflection and near-infrared blocking filter provided,
The following formulas (1) to (4):
n ₁ > n ₂ > n ₃ (1)
| N ₂ − (n ₁ + n ₃ ) /2|≦0.07 (2)
1.56 ≦ n ₁ ≦ 1.71 (3)
1.50 ≦ n ₂ ≦ 1.70 (4)
(Where n ₁ is the refractive index of the transparent substrate, n ₂ is the refractive index of the intermediate layer, and n ₃ is the refractive index of the hard coat layer)
The filling,
The thickness d (nm) of the intermediate layer is in the range of 65 to 103 nm, and one or more dyes contained in the near infrared absorption layer have absorption maximums in the wavelength range of 800 to 1200 nm and the wavelength range of 580 to 605 nm. The present invention has been found to be achieved by an antireflection / near-infrared cut-off filter used for an optical filter for a plasma display panel characterized by having

  Preferred embodiments of the anti-reflection / near-infrared blocking filter used in the optical filter for plasma display panel of the present invention are as follows.

(1) It is preferable that the transparent adhesive layer is provided on the near-infrared absorption layer. Attaching with a PDP display surface or another optical filter becomes easy.
The said transparent adhesive layer contains the pigment | dye for reducing a polymer and visible light transmittance | permeability. In the anti-reflection / near-infrared shielding filter of the present invention, the visible light transmittance can be easily adjusted by including such a dye in the transparent adhesive layer, and thus obtained when mounted on a PDP. The image can be easily viewed with good contrast.
The transparent pressure-sensitive adhesive layer preferably contains 0.01 to 0.5% by mass, particularly 0.05 to 0.15% by mass, based on the polymer, of a dye for reducing the visible light transmittance.
(2) One or more dyes contained in the near infrared absorption layer are one or more dyes having an absorption maximum in the wavelength range of 800 to 1200 nm, and one or more dyes having an absorption maximum in the wavelength range of 580 to 605 nm. Made of pigment.
(3) As a pigment | dye contained in a near-infrared absorption layer, a diimonium type pigment | dye is included. The diimmonium dye generally has an absorption maximum in a wavelength range of 800 to 1200 nm. Great near-infrared shielding effect. When the near-infrared absorbing layer contains a diimmonium salt-based dye, it is preferable not to contain a nickel complex compound (eg, bis (dithiobenzyl) nickel complex). This is because the nickel complex compound tends to alter the diimmonium dye.
(4) The intermediate layer, the hard coat layer, and the low refractive index layer are all coating layers. Productivity is improved.
(5) The refractive index n ₃ of the hard coat layer is in the range of 1.49 to 1.60. Anti-reflection property is improved.
(6) A PET film is used as the transparent substrate, and the refractive index n ₂ of the intermediate layer is 1.65 or less. Anti-reflection property is improved.
(7) Although a transparent film is generally used as the transparent substrate, it is preferable that the film contains an ultraviolet absorber. Thereby, the pigment deterioration of the near-infrared absorbing layer can be effectively prevented.
When a diimmonium dye is used as the dye of the near-infrared absorbing layer, the ultraviolet absorber may be a cyclic imino ester, particularly 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxa). Dinon-4-one) is preferably used.
(8) The hard coat layer is a cured layer of a composition containing an ultraviolet curable resin. Productivity is improved.

  The present invention also resides in an optical filter for a plasma display panel including the antireflection / near-infrared shielding filter described above.

  The present invention also provides a plasma display panel characterized in that the above optical filter for a plasma display panel is bonded to the surface of an image display glass plate.

  The anti-reflection / near-infrared blocking filter of the present invention is a film having anti-reflection and near-infrared blocking functions that can be suitably used for an optical filter for a plasma display panel (PDP). That is, the antireflection / near-infrared blocking filter of the present invention comprises a specific near-infrared absorbing layer and a specific anti-reflection layer (intermediate layer, hard coat layer, low refractive index layer) as described above on a single transparent substrate. Excellent characteristics as an optical filter for PDP (e.g., almost no interference fringes are generated, and when mounted on a PDP, it is easy to see the image with good contrast. Durability), each layer is gaining while complementing each other's characteristics.

  In particular, by introducing a pigment that cuts visible light into the transparent pressure-sensitive adhesive layer, it is possible to view a natural color image.

  Therefore, it can be said that the plasma display panel including the plasma display panel optical filter having the above characteristics can provide an image with excellent contrast and has excellent durability.

  The antireflection / near-infrared shielding filter used in the optical filter for PDP of the present invention has a basic structure in which an antireflection functional layer and a near-infrared absorption functional layer are provided on a single transparent substrate.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view showing an example of a preferred embodiment of an antireflection / near-infrared shielding filter of the present invention. In FIG. 1, on one surface of a transparent substrate 11, an intermediate layer 12 having good adhesion to the transparent substrate, a hard coat layer 13 for protecting the transparent substrate, and a refractive index lower than that of the hard coat layer The low refractive index layer 14 is laminated in order, and on the other surface of the transparent substrate 11, a near infrared absorption layer 15 and a transparent adhesive layer 16 are laminated thereon. When affixed to a PDP display, this filter or an optical filter having this filter is disposed and affixed so that external light enters from the low refractive index layer 14 side. The transparent adhesive layer 16 may be omitted, but is preferably provided. Attaching with a PDP display surface or another optical filter becomes easy. The transparent pressure-sensitive adhesive layer preferably contains a dye for reducing the visible light transmittance, so that the image can be easily viewed with good contrast. A color correction layer or the like may be provided on the near infrared absorption layer 15. Further, when an electromagnetic wave shielding layer is required, for example, a transparent substrate having a transparent adhesive layer and an electromagnetic wave shielding layer is stuck on the transparent adhesive layer 16 so that the electromagnetic wave shielding layer and the transparent adhesive layer 16 face each other. The transparent substrate 11 is generally a transparent plastic film.

In the present invention, the transparent substrate 11, the intermediate layer 12, and the hard coat layer 13 are represented by the following formulas (1) to (4):
n ₁ > n ₂ > n ₃ (1)
| N ₂ − (n ₁ + n ₃ ) /2|≦0.07 (2)
1.56 ≦ n ₁ ≦ 1.71 (3)
1.50 ≦ n ₂ ≦ 1.70 (4)
(Where n ₁ is the refractive index of the transparent substrate, n ₂ is the refractive index of the intermediate layer, and n ₃ is the refractive index of the hard coat layer)
And the thickness d (nm) of the intermediate layer 12 is in the range of 65 to 103 nm.

  That is, the inner intermediate layer and hard coat layer of the antireflection layer (intermediate layer, hard coat layer and low refractive index layer) of the present invention and the transparent substrate have the above refractive index and relative refractive index relationship. is doing. By selecting such a refractive index relationship and combining it with the thickness of the intermediate layer, the antireflection effect, interference fringe reduction effect, etc. of the present invention can be exhibited. In particular, the formulas (1) and (2) show a unique relationship that does not exist in the past, and such a relationship has an antireflection function on one surface of the transparent substrate of the present invention, and a near-infrared shield on the other surface. In the case of having a function, they do not adversely affect each characteristic, but rather complement each other, and exhibit good characteristics as a whole.

In the above formula, the refractive index n ₁ of the transparent substrate is generally in the range of 1.56 to 1.71, preferably in the range of 1.60 to 1.66, particularly preferably in the range of 1.64 to 1.65. The refractive index n ₂ of the intermediate layer is generally in the range of 1.50 to 1.70, preferably in the range of 1.54 to 1.65, particularly preferably in the range of 1.55 to 1.62. By selecting such a range and combining it with the thickness of the intermediate layer, an interference fringe reduction effect can be exhibited particularly.

  The range of the thickness d (nm) of the intermediate layer is preferably in the range of 65 to 77 nm, 78 to 93 nm, or 88 to 103 nm. These three ranges correspond to three light peak wavelength regions (for example, three wavelength regions near 450 nm, 545 nm, and 610 nm) corresponding to the RGB regions of the three-wavelength fluorescent lamp. With such a thickness d (nm), the light reflected at each specific peak wavelength can be canceled out. Therefore, in the overall design of the anti-reflection / near-infrared cut-off filter, it is possible to dramatically reduce interference fringes corresponding to each specific peak wavelength that becomes an obstacle.

The thickness d (nm) of this intermediate layer is given by the following formula (5):
d = λ / (4 × n ₂ ) (5)
(Where λ is the wavelength (nm) of the light targeted for interference fringe reduction)
The range corresponds to the value obtained by. That is, the three ranges forming the range of the thickness d (nm) of the intermediate layer of the present invention are the three-wavelength type considered in the present invention as the wavelength λ (nm) of the light of the above formula (5). It is obtained by selecting and applying values corresponding to three wavelength peak regions corresponding to each of the RGB regions included in the fluorescent lamp, that is, around 450 nm, 545 nm, and 610 nm. It is a possible range. The values of the peak wavelengths of the three lights corresponding to the RGB regions included in the three-wavelength fluorescent lamp are slightly different depending on the design of the respective fluorescent lamps. Of course, it is also possible to apply to the above. It is naturally possible to apply a value intentionally shifted from the true center value of the peak wavelength to the above equation (5).

  The thickness d (nm) of the intermediate layer can be set to a value in the range of 65 to 103 nm, but the actual range of 65 to 77 nm, the range of 78 to 93 nm, and the range of 88 to 103 nm. Therefore, it is possible to set the value within a selected range as follows.

  The range of 65 to 77 nm of the thickness d (nm) of the intermediate layer is preferably in the range of 68 to 75 nm, particularly preferably in the range of 70 to 73 nm, so that the specific peak wavelength centered at 450 nm is obtained. It is possible to effectively suppress the generation of interference fringes.

  The intermediate layer thickness d (nm) in the range of 78 to 93 nm is preferably in the range of 83 to 91 nm, particularly preferably in the range of 85 to 89 nm, with respect to a specific peak wavelength centered at 545 nm. It is possible to effectively suppress the generation of interference fringes.

  The range of 88 to 103 nm of the thickness d (nm) of the intermediate layer is preferably in the range of 92 to 101 nm, particularly preferably in the range of 94 to 99 nm, so that the specific peak wavelength centered at 610 nm is obtained. It is possible to effectively suppress the generation of interference fringes.

The refractive index n ₂ of the intermediate layer is generally in the range of 1.50 to 1.70, preferably in the range of 1.54 to 1.65, particularly preferably in the range of 1.55 to 1.62. By selecting such a range and combining it with the thickness of the intermediate layer, the interference fringe reduction effect of the present invention can be exhibited.

The value of the refractive index n ₂ of the intermediate layer is expressed by the following formula:
| N ₂ − (n ₁ + n ₃ ) / 2 |
In general, it is preferable that the value obtained by the above is 0.07 or less, preferably 0.05 or less, particularly 0.03 or less. By setting the refractive index n ₂ value of the intermediate layer according to this standard and reducing the difference in the refractive index of each layer, an anti-reflection / near-infrared shielding filter with particularly enhanced interference fringe generation suppression effect and anti-reflection effect Obtainable.

  The material of the intermediate layer is not particularly limited as long as it has a refractive index capable of achieving the above-described refractive index relationship between the respective layers of the present invention and has an adhesive force with a predetermined thickness. Is possible. Preferable examples include acrylic resins (including sulfur-modified acrylic resins), EVA (ethylene vinyl acetate copolymer), polyester resins, polyurethane resins, polyvinyl acetal resins (for example, polyvinyl formal, polyvinyl butyral (PVB resin). ), Modified PVB), and vinyl chloride resin. In particular, acrylic resins (particularly sulfur-modified acrylic resins), EVA, polyester resins, and polyurethane resins are preferred.

  As said acrylic resin, the copolymer of (meth) acrylic acid ester, such as methyl methacrylate, butyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate, and comonomers, such as acrylic acid and methacrylic acid; or , By introducing a functional group such as a carboxyl group, a hydroxyl group, a methylol group, or a glycidyl group into the side chain of these copolymers, an aliphatic isocyanate such as tetramethylene diisocyanate or trimethylhexamethylene diisocyanate, or TDI (tolylene diisocyanate), An acrylic urethane resin obtained by crosslinking with an aromatic isocyanate such as MDI (diphenylmethane diisocyanate) or NDI (naphthalene diisocyanate) can be exemplified. A particularly preferable example is a sulfur atom as an acrylic resin monomer. By polymerization reaction using a monomer having a functional group having, or is obtained by reacting a compound having a sulfur atom in the functional group of the acrylic resin polymer, mention may be made of sulfur-modified acrylic resin.

  Moreover, when using EVA resin, a silane coupling agent can be added to EVA resin for the purpose of the adhesive force improvement. Known silane coupling agents for this purpose are, for example, γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tris- (β-methoxyethoxy) silane; γ-methacryloxy. Propyltrimethoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane; γ-glycidoxypropyltrimethoxysilane; vinyltriacetoxysilane; γ-mercaptopropyltrimethoxysilane; γ-aminopropyltrimethoxysilane N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be mentioned. The compounding amount of these silane coupling agents is generally 5 parts by mass or less, preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the EVA resin.

  Furthermore, a crosslinking aid can be added to the EVA resin in order to improve the gel fraction of the EVA resin and improve the durability. As crosslinking aids used for this purpose, known tri-functional crosslinking aids such as triallyl cyanurate and triallyl isocyanurate as well as monofunctional crosslinking aids such as NK ester (trade name) are known. Etc. can also be mentioned. Generally the compounding quantity of these crosslinking adjuvants is 10 mass parts or less with respect to 100 mass parts of EVA resin, Preferably it is 1-5 mass parts.

  Furthermore, hydroquinone; hydroquinone monomethyl ether; p-benzoquinone; methyl hydroquinone and the like can be added for the purpose of improving the stability of the EVA resin, and the blending amount thereof is generally 5 parts by mass with respect to 100 parts by mass of the EVA resin. It is as follows.

  Said polyester resin has branched glycol as a structural component. Examples of the “branched glycol” herein include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, and 2-methyl-2-butyl-1 , 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3- Propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, 2,2-di-n-hexyl-1,3-propanediol And the like can be given.

  The branched glycol is preferably used in a proportion of 10 mol% or more, more preferably 20 mol% or more in the total polyhydric alcohol. As the polyhydric alcohol other than the branched glycol, ethylene glycol is most preferable. If it is a small amount, diethylene glycol, propylene glycol, butanediol, hexanediol, 1,4-cyclohexanedimethanol and the like may be used.

  As the polyvalent carboxylic acid for synthesizing the polyester resin, terephthalic acid and isophthalic acid are most preferable. If the amount is small, an aromatic dicarboxylic acid such as diphenylcarboxylic acid or 2,6-naltalenedicarboxylic acid may be added and copolymerized. In addition to the polyvalent dicarboxylic acid, a dicarboxylic acid having a sulfonic acid group or the like is preferably used in the range of 1 to 10 mol% in order to impart water dispersibility.

  The polyurethane-based resin is, for example, a resin containing a block type isocyanate group, and a heat-reactive water-soluble polyurethane having a terminal isocyanate group blocked with a hydrophilic group (hereinafter referred to as “block”). Can be mentioned. Examples of the isocyanate group blocking agent include bisulfites, phenols containing sulfonic acid groups, alcohols, lactams, oximes, and active methylene compounds. Among the above blocking agents, bisulfites are particularly preferred as those having suitable heat treatment temperature and heat treatment time and widely used industrially.

  The blocked isocyanate group makes the urethane prepolymer hydrophilic or water-soluble. When heat energy is applied in the drying or heat setting process during film production, the blocking agent is removed from the isocyanate group, so that it self-crosslinks to form a network, and the mixed polyester resin is mixed with the network. Immobilize. It also reacts with the terminal groups of the copolyester resin.

  During the preparation of the coating solution for forming the intermediate layer, the polyurethane resin is hydrophilic and thus has poor water resistance. However, when the thermal reaction is completed by coating, drying, and heat setting, the hydrophilic group of the polyurethane resin (that is, blocked) Since the agent is removed, a layer with good water resistance is formed.

  The urethane prepolymer used for the polyurethane resin has (1) an organic polyisocyanate having two or more active hydrogen atoms in the molecule, or two active hydrogen atoms in the molecule, and a molecular weight of 200-20. 2,000 compounds, (2) a compound obtained by reacting an organic polyisocyanate having two or more isocyanate groups in the molecule, and (3) a chain extender having at least two active hydrogen atoms in the molecule. Yes, it has a terminal isocyanate group.

  Generally known as the compound (1) is a compound containing two or more hydroxyl groups, carboxyl groups, amino groups or mercapto groups in the terminal or molecular chain, and particularly preferred compounds include polyether polyols. , Polyester polyol, polyether ester polyol, and the like.

  Examples of the polyether polyol include polymers of compounds such as alkylene oxides such as ethylene oxide and propylene oxide; styrene oxide; epichlorohydrin; or random copolymers thereof, block copolymers thereof, and many of these compounds. There are polymers obtained by addition polymerization to a monohydric alcohol.

  Examples of the polyester polyol and the polyether ester polyol mainly include linear or branched compounds. Polyvalent saturated or unsaturated carboxylic acids such as succinic acid, adipic acid, phthalic acid and maleic anhydride, or polyvalent carboxylic acids such as carboxylic acid anhydride, ethylene glycol, diethylene glycol, 1,4-butanediol, Polyalkylene ether glycols such as polyvalent saturated or unsaturated alcohols such as neopentyl glycol, 1,6-hexanediol, trimethylolpropane, relatively low molecular weight polyethylene glycol, and relatively low molecular weight polypropylene glycol; Alternatively, it can be obtained by condensing with a polyhydric alcohol such as a mixture of these alcohols. Further examples of polyester polyols include polyesters obtained from lactones and hydroxy acids. In addition, as the polyether ester polyol, polyether esters obtained by adding ethylene oxide or propylene oxide or the like to previously produced polyesters can also be used.

  Examples of the organic polyisocyanate (2) include isomers of tolylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate; aromatic aliphatic diisocyanates such as xylylene diisocyanate; isophorone diisocyanate, 4,4 -Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate; Aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate; or a mixture of these compounds, or trimethylolpropane And added polyisocyanates; and the like.

  Examples of the chain extender (3) include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol; polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol; ethylenediamine Diamines such as hexamethylenediamine and piperazine; aminoalcohols such as monoethanolamine and diethanolamine; thiodiglycols such as thiodiethylene glycol; water;

  In order to synthesize the urethane polymer, the reaction is usually performed at a temperature of 150 ° C. or lower, preferably 70 to 120 ° C. for 5 minutes to several hours by a single-stage or multi-stage isocyanate polyaddition method using the chain extender. Let The ratio of isocyanate groups to active hydrogen atoms can be freely selected as long as it is 1 or more, but it is necessary that free isocyanate groups remain in the obtained urethane prepolymer. Furthermore, the content of free isocyanate groups may be 10% by mass or less, but considering the stability of the urethane polymer aqueous solution after being blocked, it is preferably 7% by mass or less.

  The obtained urethane prepolymer is blocked using a blocking agent (preferably bisulfite). When bisulfite is used, it is mixed with an aqueous bisulfite solution, and the reaction is allowed to proceed with good stirring for about 5 minutes to 1 hour. The reaction temperature is preferably 60 ° C. or lower. Thereafter, it is diluted with water to an appropriate concentration to obtain a heat-reactive water-soluble urethane composition. When this composition is used, it is adjusted to an appropriate concentration and viscosity. When the above composition is heated to about 80 to 200 ° C., the bisulfite of the blocking agent is dissociated and the active isocyanate group is regenerated, so that it is caused by a polyaddition reaction that occurs within or between the prepolymer molecules. A polyurethane polymer is produced or has the property of causing addition to other functional groups.

  As an example of the polyurethane resin having a block type isocyanate group, Elastron (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be mentioned. Elastolone is an isocyanate group blocked with sodium bisulfite, and is water-soluble because a carbamoylsulfonate group having strong hydrophilicity is present at the molecular end.

  When the polyester resin (a) and the polyurethane resin (b) are used in combination to form an intermediate layer, the polyester resin (a) and the polyurethane resin ( The mass ratio with b) is preferably (a) :( b) = 90: 10 to 10:90, more preferably (a) :( b) = 80: 20 to 20:80. .

  A catalyst may be added to the coating solution for forming the intermediate layer when the thermal crosslinking reaction is promoted. As the catalyst, for example, various chemical substances such as inorganic substances, salts, organic substances, alkaline substances, acidic substances and metal-containing organic compounds are used. Moreover, in order to adjust pH of aqueous solution, you may add an alkaline substance or an acidic substance.

  Various additives such as an antistatic agent, a pigment, an organic filler, and a lubricant may be mixed in the coating liquid for forming the intermediate layer within a range not impairing the effect thereof. Furthermore, since the coating liquid is aqueous, other water-soluble resins, water-dispersible resins, emulsions, and the like may be added to the coating liquid in order to further improve the performance within a range that does not impair the effect.

  In order to apply | coat the coating liquid for intermediate | middle layer formation to a transparent substrate (usually transparent film), it can carry out by a well-known arbitrary method. Examples thereof include reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor method, impregnation / coating method, curtain coating method, and the like.

  The intermediate layer 12 is formed on the transparent substrate 13. The refractive index, material, thickness, etc. of this transparent substrate will be described below.

The refractive index n ₁ of the transparent substrate is generally in the range of 1.56 to 1.71, preferably in the range of 1.60 to 1.66, particularly preferably in the range of 1.64 to 1.65. By using such a transparent substrate having a relatively low refractive index, it is possible to effectively cancel interference fringes while enabling the use of a hard coat layer having a relatively low refractive index. The superiority can be particularly demonstrated.

As the material of the transparent substrate, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic resin, polycarbonate; polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoropropylene copolymer (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF) And plastic films such as fluororesins such as polyvinyl fluoride (PVF). A PET film is particularly preferable from the viewpoints of transparency and flexibility, and the present invention can be suitably applied to PET having a refractive index of 1.65. In a preferred embodiment of the present invention, when a PET film is used, the refractive index n ₂ of the intermediate layer is set to a value of 1.65 or less corresponding to the refractive index of the PET film.

  The thickness of the transparent substrate is preferably about 6 to 250 μm.

  In order to protect the pigment | dye of a near-infrared absorption layer, it is preferable that the plastic film which is the said transparent substrate contains the ultraviolet absorber. Examples of the ultraviolet absorber include 2-hydroxy-4-octoxybenzophenone; benzophenones such as 2-hydroxy-4-methoxy-5-sulfobenzophenone; 2- (2′-hydroxy-5-methylphenyl) benzo Benzotriazoles such as triazole; phenyl salicylates; hindered amines such as pt-butylphenyl salsylates; 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxa And cyclic iminoesters such as dinon-4-one). In particular, benzotriazole type and cyclic imino ester type are preferable. The plastic film preferably contains 0.2 to 3% by mass, particularly 0.5 to 1.5% by mass. Thereby, the light deterioration of the pigment | dye of a near-infrared absorption layer can be suppressed, and the near-infrared shielding effect can be hold | maintained highly and for a long term.

  Further, there are anti-aging agents such as amine-based; phenol-based; bisphenyl-based; hindered amine-based, such as di-t-butyl-p-cresol; bis (2,2,6,6-tetramethyl-4- Piperazil) sebacate and the like may be contained.

  On the transparent intermediate layer 13, a hard coat layer 12 is provided. The refractive index, material, thickness, etc. of the hard coat layer will be described below.

The refractive index n ₃ of the hard coat layer is generally in the range of 1.49 to 1.60, preferably in the range of 1.51 to 1.58, particularly preferably in the range of 1.53 to 1.56. By using a refractive index selected from such a range, preferred implementation of the present invention is possible. By using such a hard coating layer having a relatively low refractive index, the reflection of the present invention does not increase the manufacturing cost without using a large amount of filler in the hard coating layer. The superiority of the prevention / near-infrared shielding filter can be exhibited.

  The hard coat layer is a layer made of a cured film of a thermosetting resin or an ultraviolet curable resin. In particular, the hard coat layer can be provided on the transparent substrate very easily by using the ultraviolet curable resin.

  As the thermosetting resin, a thermosetting silicone composition (for example, methyltrimethoxysilane that forms an organic polysiloxane) is preferable, and three-dimensional crosslinking is performed in the dehydration condensation of silanol groups to obtain a high hardness coating. Generally, it can be cured by heating at 80 to 220 ° C. for 10 minutes to 1 hour.

  Further, as the curable resin, a resin or oligomer having an ethylenic double bond (preferably an acryloyl group or a methacryloyl group) can be used, and this can be generally made into a hard coat layer by photocuring.

  Alternatively, the hard coat layer is also preferably a layer made of a cured film of a curable resin containing silica fine particles. In particular, a hard coat layer can be provided on a transparent substrate very easily by using an ultraviolet curable resin.

  The primary particle size of the silica fine particles is preferably in the range of 1 to 200 nm.

In a preferred embodiment, the hard coat layer includes, as the metal oxide fine particles, ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide), Sb ₂ O ₃ , SbO ₂ , In ₂ O. ₃ , SnO ₂ , ZnO, TiO ₂ , ZrO ₂ , CeO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , LaO _2, and Ho ₂ O _3, etc. Can be used in combination. ITO, ATO, Sb ₂ O ₃ , SbO ₂ , In ₂ O ₃ , SnO ₂ , ZnO are particularly useful for imparting conductivity to the hard coat layer, and include TiO ₂ , ZrO ₂ , CeO ₂ , Al _2. O ₃ , Y ₂ O ₃ , La ₂ O ₃ , LaO ₂ and Ho ₂ O ₃ are particularly useful for increasing the refractive index of the hard coat layer. Accordingly, the refractive index of the hard coat layer can be adjusted, and charging can be prevented by imparting conductivity.

  As the ultraviolet curable resin, a known ultraviolet curable resin (including a polymerizable oligomer, a polyfunctional monomer, a monofunctional monomer, a photopolymerization initiator, an additive, and the like) can be used.

Examples of the ultraviolet curable resin (multifunctional and monofunctional monomer, oligomer) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- Ethylhexyl polyethoxy (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, phenyloxyethyl (meth) acrylate, tricyclodecane mono (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (Meth) acrylate, acryloylmorpholine, N-vinylcaprolactam, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenyloxyethyl (meth) acrylate , Neopentyl glycol di (meth) acrylate, neopentyl glycol dipropoxy di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, 1,6-hexanediol Di (meth) acrylate, nonanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris [(meth) acryloxyethyl] isocyanurate (Meth) acrylate monomers such as ditrimethylolpropane tetra (meth) acrylate;
Polyol compounds (for example, ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butyl-1, Polyols such as 3-propanediol, trimethylolpropane, diethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-dimethylolcyclohexane, bisphenol A polyethoxydiol, polytetramethylene glycol, the polyols and succinic acid, maleic acid Polyester polyols which are reaction products of polybasic acids such as itaconic acid, adipic acid, hydrogenated dimer acid, phthalic acid, isophthalic acid, terephthalic acid, etc., or their acid anhydrides, and the above-mentioned polyols and ε-capro Polycaprolactone polyols which are reactants with kuton, reaction products of the above-mentioned polyols with the above-mentioned polybasic acids or ε-caprolactone of these acid anhydrides, polycarbonate polyols, polymer polyols, etc.) and organic polyisocyanates (for example, , Tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, dicyclopentanyl diisocyanate, hexamethylene diisocyanate, 2,4,4'-trimethylhexamethylene diisocyanate, 2,2'-4- Trimethylhexamethylene diisocyanate and the like) and a hydroxyl group-containing (meth) acrylate (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4- Droxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, cyclohexane-1,4-dimethylol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, Bisphenol type epoxy resins such as polyurethane (meth) acrylate, bisphenol A type epoxy resin, bisphenol F type epoxy resin and (meth) acrylic, which are reaction products of dipentaerythritol hexa (meth) acrylate, glycerin di (meth) acrylate, etc. Examples include (meth) acrylate oligomers such as bisphenol-type epoxy (meth) acrylate, which are reaction products of acids. These compounds can be used alone or in combination. These ultraviolet curable resins may be used as a thermosetting resin together with a thermal polymerization initiator.

  For the hard coat layer, among the above UV curable resins (polyfunctional monomers, monofunctional monomers, oligomers), pentaerythritol tri (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa It is preferable to mainly use a hard polyfunctional monomer such as (meth) acrylate.

  The ultraviolet curable resin is generally composed of an oligomer, if necessary, a reactive diluent (polyfunctional monomer, monofunctional monomer), and a photopolymerization initiator as described above. Examples of photopolymerization initiators include benzoin, benzophenone, benzoyl methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, dibenzyl, 5-nitroacenaphthene, hexachlorocyclopentadiene, p-nitrodiphenyl, p-nitroaniline. 2,4,6-trinitroaniline, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone; acetophenone, acetophenone benzyl ketal, anthraquinone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone compounds, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimene Xylbenzophenone, 4,4′-diaminobenzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, Carbazole, xanthone, 1,1-dimethoxydeoxybenzoin, 3,3′-dimethyl-4-methoxybenzophenone, thioxanthone compound, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 1- (4-dodecylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, triphenylamine, 2,4,6-trimethylbenzoyl Diphenylphosphine oxide, bis- (2,6-dimethyl) Toxibenzoyl) -2,4,4-trimethylpentylphosphine oxide, bisacylphosphine oxide, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Fluorenone, fluorene, benzaldehyde, Michler's ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 3-methylacetophenone, 3,3 ′, 4,4′-tetra ( t-butylperoxycarbonyl) benzophenone (BTTB) and the like, and combinations of BTTB and dye sensitizers such as xanthene, thioxanthene, coumarin, ketocoumarin and the like. Of these, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one is preferred.

  These can be used alone or in combination of two or more. The content of the photopolymerization initiator is preferably 5 parts by mass or less with respect to 100 parts by mass of the ultraviolet curable resin.

  The ultraviolet curable resin may further contain a silicone polymer. Generally, it is a graft copolymer having silicone as a side chain, and preferably an acrylic graft copolymer having silicone as a side chain.

  In the present invention, various additives can be added as necessary to the above. Examples of these additives include antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, and anti-aging. Agent, thermal polymerization inhibitor, colorant, leveling agent, surfactant, storage stabilizer, plasticizer, lubricant, solvent, inorganic filler, organic filler, filler, wettability improver, coating surface improver, etc. Can be mentioned.

  The hard coat layer is composed mainly of the above components, but is excellent in various functions by further modification of the above oligomer or monomer, or further use of other functional resins and additives. A hard coat layer can be obtained.

  The thickness of the hard coat layer is preferably 1 to 20 μm (particularly 1 to 15 μm).

  On the hard coat layer 13, a low refractive index layer 14 is provided. The material, refractive index, thickness, etc. of the low refractive index layer will be described below.

  The low refractive index layer can be formed of, for example, a fluorine or non-fluorine low refractive index organic thin film.

  Examples of the non-fluorine-based organic thin film include acrylic resins, silicone resins, acrylic silicon resins, and urethane resins that are used for the hard coat layer.

  Fluorine organic thin films include FET (fluoroethylene / propylene copolymer), PTFE (polytetrafluoroethylene), ETFE (ethylene / tetrafluoroethylene), PVF (polyvinyl fluoride), PVD (polyvinylidene fluoride), etc. Can be mentioned.

  Further, in order to impart antifouling property, slipperiness, etc., fluorine-based and silicone-based additives may be added. Among these, a silicone resin or an acrylic resin is preferable because it is inexpensive.

  The low refractive index layer may be a layer made of a cured film of a thermosetting resin or an ultraviolet curable resin used for a hard coat layer, and an ultraviolet curable resin is particularly suitable in terms of hardness and handling. is there.

  Since such an organic thin film is generally a low refractive index thin film having a refractive index of 1.3 to 1.6, it is suitable in the present invention.

  Further, preferably, by filling the organic thin film with a filler such as hollow silica (porous silica), the refractive index can be lowered and the antireflection performance can be improved. In particular, since hollow silica is an inorganic compound filler, a decrease in refractive index due to this is preferable in that a harder low refractive index thin film can be formed as compared with a decrease in refractive index due to an organic additive.

  Since the hollow silica is hollow and contains air inside, it has a very low refractive index (about 1.34 to 1.44) compared to ordinary silica (refractive index: about 1.46). This can be created by covering the surface of porous silica fine particles with an organosilicon compound or the like and closing the pore entrance. The average particle diameter of the hollow silica can generally be in the range of 1 nm to 1 μm, preferably 5 to 200 nm, and particularly preferably 10 to 100 nm. From the viewpoint of the size of the contribution to lowering the refractive index, the larger the particle size, the better. However, if the particle diameter exceeds about 1 μm, the transparency is extremely lowered and the contribution of diffuse reflection becomes large, and it looks whitish. . From the viewpoint of transparency, the smaller the particle size, the better. However, in addition to the above-mentioned contribution to lowering the refractive index, hollow silica fine particles tend to aggregate, especially when the particle size is smaller than about 0.5 nm. Uniform dispersion is not easy.

  The thickness of the low refractive index layer is preferably an optical film thickness within a range in which the antifouling function can be obtained in order to achieve both the antireflection function and the antifouling function, and is in the range of 50 to 500 nm. For example, it is preferable to set it to about ¼λ (= 125 nm) of light having a wavelength of 500 nm.

  By forming such an organic thin film on the hard coat layer having a high refractive index as the outermost layer of the antireflection film, it is possible to obtain an antireflection function, and to obtain excellent antifouling properties and scratch resistance. Can do.

  In order to form each layer of the antireflection layer, as described above, the polymer (preferably UV curable resin) is blended with the fine particles as necessary, and the obtained coating solution is applied, and then dried. If necessary, it is heat-cured, or after coating, if necessary, it is dried and irradiated with ultraviolet rays. In this case, each layer may be applied and cured one by one, or all the layers may be applied and then cured together.

  As a specific method of coating, a method of coating a coating solution in which an ultraviolet curable resin containing an acrylic monomer or the like is made into a solution with a solvent such as toluene is coated with a gravure coater, and then dried, and then cured by ultraviolet rays. Can be mentioned. This wet coating method has the advantage that the film can be uniformly formed at high speed at low cost. After this coating, for example, by irradiating and curing with ultraviolet rays, the effect of improving the adhesion and increasing the hardness of the film can be obtained.

  In the case of ultraviolet curing, many light sources that emit light in the ultraviolet to visible range can be used as the light source, such as ultra-high pressure, high pressure, low pressure mercury lamp, chemical lamp, xenon lamp, halogen lamp, mercury lamp, carbon arc lamp, incandescent lamp. And laser light. The irradiation time cannot be determined unconditionally depending on the type of lamp and the intensity of the light source, but is about several seconds to several minutes. Moreover, in order to accelerate curing, the laminate may be preheated to 40 to 120 ° C. and irradiated with ultraviolet rays.

  The antireflection layer of the present invention is preferably formed by coating as described above, but may be formed by a vapor phase film forming method. Usually, the low refractive index layer can be formed by physical vapor deposition or chemical vapor deposition. Examples of the physical vapor deposition method include a vacuum vapor deposition method, a sputtering method, an ion plating method, and a laser ablation method, but it is generally preferable to form a film by the sputtering method. Examples of the chemical vapor deposition method include an atmospheric pressure CVD method, a low pressure CVD method, and a plasma CVD method.

  A near-infrared absorbing layer (that is, a near-infrared shielding layer) is generally obtained by forming a layer containing a pigment or the like on the surface of a transparent substrate. The near-infrared absorbing layer is obtained by coating, drying, and curing as necessary, for example, a coating liquid containing a pigment and a binder resin.

  As the dye, those having an absorption maximum at a wavelength of 800 to 1200 nm and those having an absorption maximum wavelength of 575 to 605 nm are generally used. A dye having an absorption maximum in both wavelength regions can be used, but generally one or more of each is used. Examples of dyes having an absorption maximum at a wavelength of 800 to 1200 nm include phthalocyanine dyes, metal complex dyes, nickel dithiolene complex dyes, cyanine dyes, squarylium dyes, polymethine dyes, azomethine dyes, and azo dyes. Examples thereof include dyes, polyazo dyes, diimonium dyes, aminium dyes, and anthraquinone dyes. Particularly preferred are diimonium dyes, cyanine dyes, and squarylium dyes, and particularly preferred are diimonium dyes.

  It is preferable to use a diimmonium compound represented by the following formula, which has a large absorption in the near infrared region, a wide absorption region, and a high transmittance in the visible region.

[Wherein R ^{1 to} R ⁸ represent a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an aralkyl group, or an alkynyl group, and may be the same or different. R ^{9 to} R ¹² represent a hydrogen atom, a halogen atom, an amino group, a cyano group, a nitro group, a carboxyl group, an alkyl group, or an alkoxyl group, and may be the same or different. What can couple | bond a substituent with R < ₁ > -R < ₁₂ > may have a substituent. X ⁻ represents an anion. ]
Specific examples of R ^{1 to} R ⁸ include the following. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, n-amyl group, n-hexyl group, n-octyl group, Examples include 2-hydroxyethyl group, 2-cyanoethyl group, 3-hydroxypropyl group, 3-cyanopropyl group, methoxyethyl group, ethoxyethyl group, butoxyethyl group. Examples of the aryl group include a phenyl group, a fluorophenyl group, a chlorophenyl group, a tolyl group, diethylaminophenyl, and a naphthyl group. Examples of the alkenyl group include a vinyl group, a propenyl group, a butenyl group, and a pentenyl group. Examples of the aralkyl group include a benzyl group, a p-fluorobenzyl group, a p-chlorophenyl group, a phenylpropyl group, and a naphthylethyl group.

R ^{9 to} R ¹² are hydrogen, fluorine, chlorine, bromine, diethylamino group, dimethylamino group, cyano group, nitro group, methyl group, ethyl group, propyl group, trifluoromethyl group, methoxy group, ethoxy group, propoxy Groups and the like. X ⁻ is fluorine ion, chlorine ion, bromine ion, iodine ion, perchlorate ion, hexafluoroantimonate ion, hexafluorophosphate ion, tetrafluoroborate ion, bis (trifluoromethanesulfonyl) imido ion. preferable. Examples of these commercially available products include “Kayasorb IRG-022, IRG-023, IRG-024” manufactured by Nippon Kayaku Co., Ltd., “CIR-1080, CIR-1081, CIR-1083, CIR-1085” manufactured by Nippon Carlit Co., Ltd. Can be mentioned.

  Examples of near-infrared absorbing dyes other than diimmonium-based compounds include “EEXCALA IR-1, IR-2, IR-3, IR-4, IR-10, IR-10A, IR-12, IR manufactured by Nippon Shokubai Co., Ltd. -14, TXEX-805K, TX-EX807K, TX-EX808K, TX-EX811K, TX-EX813K, phthalocyanine compounds such as “MIR-369, MIR-389” manufactured by Mitsui Chemicals; “SIR-” manufactured by Mitsui Chemicals, Inc. 128, SIR-130, SIR-132, SIR-159 ”, dithiol metal complex compounds such as“ MIR-101, MIR-121 ”manufactured by Midori Chemical Co., etc. can be suitably used. Furthermore, "TZ-103, TZ-104, TZ-105, TZ-109, TZ-111, TZ-114" manufactured by Asahi Denka Co., Ltd., "CY-9, CY-10" manufactured by Nippon Kayaku Co., Ltd., Yamada Chemical Co., Ltd. “IR-301” manufactured by the company can be mentioned.

  When the near-infrared absorbing layer contains the above-mentioned diimmonium salt-based dye, it is preferable not to contain a nickel complex compound (eg, bis (dithiobenzyl) nickel complex). Nickel complex compounds tend to alter the diimmonium salt dyes. As a result, the dye deteriorates and the durability decreases.

  The dye having an absorption maximum wavelength of 575 to 605 nm (especially 575 to 595) used in the present invention mainly has a function of imparting a neon emission absorption function to the near infrared absorption layer. Thereby, the color tone can be adjusted.

  Examples of such selective absorption dyes for neon emission include cyanine dyes, squarylium dyes, anthraquinone dyes, phthalocyanine dyes, polymethine dyes, polyazo dyes, azurenium dyes, diphenylmethane dyes, and triphenylmethane dyes. Can be mentioned. Such a selective absorption dye is required to have a selective absorption of neon emission near 585 nm and a small absorption at other visible light wavelengths, so that the absorption maximum wavelength is 575 to 605 nm (especially 575 to 595) nm. And an absorption spectrum half-width of 40 nm or less is preferable. TAP-2 (manufactured by Yamada Chemical Co., Ltd.) can be mentioned as a commercial product of a dye having an absorption maximum wavelength of 575 to 605 nm.

  Further, as long as the optical properties are not greatly affected, coloring pigments, ultraviolet absorbers, antioxidants and the like may be further added.

  As a near-infrared absorption characteristic of the optical filter of the present invention, it is preferable that the transmittance at 850 to 1000 nm is 20% or less, and further 15%. Moreover, as selective absorptivity, it is preferable that the transmittance | permeability of 585 nm is 50% or less. Especially in the former case, there is an effect of reducing the transmittance in a wavelength region where malfunction of a remote controller of a peripheral device is pointed out. In the latter case, an orange color having a peak at 575 to 595 nm is color reproducibility. This has the effect of absorbing the orange wavelength, thereby improving the redness and improving the color reproducibility.

The near-infrared absorbing dye is present to achieve the required near-infrared absorption and transmission in the visible range. For example, it is preferable to make it exist in the range of 0.01-1.0 g / m < ² > as a pigment | dye on a transparent substrate. If the amount of the near-infrared absorbing dye is small, the absorption ability in the near-infrared region may be insufficient, and conversely, if it is large, the transparency in the visible light region is insufficient and the brightness of the plasma display is reduced. May decrease.

  The near-infrared absorbing dye is present on the transparent substrate in a state of being dispersed or dissolved in the resin. The resin is not particularly limited as long as it can dissolve or disperse the near-infrared absorbing dye uniformly, but polyester, acrylic, polyamide, polyurethane, polyolefin, polycarbonate, polystyrene, etc. Any of various synthetic resins, natural polymers such as gelatin and cellulose derivatives can be used. Commercially available resins include, for example, O-PET (manufactured by Kanebo Co., Ltd.), ZEONEX (manufactured by Zeon Corporation), ARTON (manufactured by JSR Corporation), Optretz (manufactured by Hitachi Chemical Co., Ltd.). And Byron (manufactured by Toyobo Co., Ltd.). Of these, polyester resins and acrylic resins are preferable because they are excellent in flexibility and adhesion to the substrate. That is, when the resin is hard, minute cracks may occur in the near-infrared absorbing layer in the manufacturing process of the optical filter of the present invention.

  The content of the near-infrared absorbing dye in the total amount of the resin and the near-infrared absorbing dye is preferably 1 to 20% by mass, particularly 2 to 10% by mass. If the content of the near-infrared absorbing dye is too small, this layer must be thickened in order to give the near-infrared absorbing layer the desired near-infrared absorbing ability. For this reason, since the application quantity of the coating liquid for forming a near-infrared absorption layer also increases, in order to improve drying efficiency, it is necessary to dry at high temperature and / or for a long time. As a result, when dried at a high temperature, the deterioration of the pigment and the poor flatness of the transparent substrate are likely to occur, and the productivity deteriorates when the drying takes a long time. On the other hand, if the content of the near-infrared absorbing dye is too large, the interaction between the dyes is likely to occur, and even if the amount of residual solvent in the near-infrared absorbing layer is reduced, the dye is likely to be modified over time. .

  The layer thickness of the near-infrared absorbing layer is generally 0.5 to 50 μm, preferably 0.5 to 30 μm, particularly preferably 0.5 to 10 μm.

  The near-infrared absorbing layer may contain a color correction pigment. Alternatively, a transparent color tone correction layer containing a color tone correction pigment may be provided in the same manner as the near infrared absorption layer. As the color correction pigment, in order to neutralize the yellowish brown to green color tone of the near-infrared shielding layer and adjust the color balance, those which are complementary colors thereof are preferable. Examples of such pigments include general pigments such as inorganic pigments, organic pigments, organic dyes, and pigments. Examples of inorganic pigments include cobalt compounds, iron compounds, chromium compounds, and examples of organic pigments include azo-based, indolinone-based, quinacridone-based, vat-based, phthalocyanine-based, naphthalocyanine-based, Examples of the organic dyes and pigments include azo, azine, anthraquinone, indigoid, oxazine, quinophthalone, squalium, stilbene, triphenylmethane, naphthoquinone, pyrarozone, and polymethine. Of these, organic pigments are preferably used in view of the balance between color developability and durability.

  The transparent adhesive layer 16 of the present invention is a layer for adhering the optical filter of the present invention to a display, and any resin can be used as long as it has an adhesive function. For example, acrylic adhesives, rubber adhesives, SEBS (styrene / ethylene / butylene / styrene) and SBS (styrene / butadiene / styrene) and other thermoplastic elastomers (TPE) as main components TPE-based pressure-sensitive adhesives and adhesives can also be used.

  The layer thickness is generally in the range of 5 to 500 μm, particularly 10 to 100 μm. In general, the optical filter can be equipped by pressing the transparent pressure-sensitive adhesive layer on the glass plate of the display.

  In this invention, it is preferable that the said transparent adhesive layer contains at least 1 sort (s) of pigment | dye which has absorption in visible region, in order to reduce (adjust) visible light transmittance | permeability. As such a dye, those having absorption almost uniformly in the entire visible light region (400 to 720 nm) are preferable, and black or dark dyes are preferable. For example, Bali First Black 3808 (manufactured by Orient Chemical Industry Co., Ltd.) can be mentioned, which is preferable. Such a pigment is preferably contained in the transparent adhesive layer in an amount of 0.01 to 0.10% by mass, particularly 0.01 to 0.05% by mass.

  When adhering the optical filter of the present invention to other optical filters, for example, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, acrylic resin (eg, ethylene- (meth)) Acrylic acid copolymer, ethylene- (meth) ethyl acrylate copolymer, ethylene- (meth) methyl acrylate copolymer, metal ion cross-linked ethylene- (meth) acrylic acid copolymer), partially saponified ethylene-acetic acid Examples include ethylene copolymers such as vinyl copolymers, carboxylated ethylene-vinyl acetate copolymers, ethylene- (meth) acryl-maleic anhydride copolymers, ethylene-vinyl acetate- (meth) acrylate copolymers. (“(Meth) acryl” means “acryl or methacryl”). In addition, polyvinyl butyral (PVB) resin, epoxy resin, phenol resin, silicone resin, polyester resin, urethane resin, rubber adhesive, thermoplastic elastomers such as SEBS and SBS can be used, but good adhesion Acrylic resin adhesives and epoxy resins are easily obtained.

  The layer thickness is generally 10 to 50 μm, preferably 20 to 30 μm. In general, the optical filter can be equipped by pressing the pressure-sensitive adhesive layer on a glass plate of a display.

  The EVA may be used as a material for the transparent adhesive layer. When EVA is used, the EVA has a vinyl acetate content of 5 to 50% by weight, preferably 15 to 40% by weight. When the vinyl acetate content is less than 5% by weight, there is a problem in transparency, and when it exceeds 40% by weight, the mechanical properties are remarkably deteriorated and the film formation becomes difficult and the films are easily blocked.

  As the cross-linking agent, an organic peroxide is suitable for heat cross-linking and is selected in consideration of sheet processing temperature, cross-linking temperature, storage stability, and the like. Examples of peroxides that can be used include 2,5-dimethylhexane-2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane-3; -Butyl peroxide; t-butylcumyl peroxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; dicumyl peroxide; α, α'-bis (t-butylperoxyisopropyl) ) Benzene; n-butyl-4,4-bis (t-butylperoxy) valerate; 2,2-bis (t-butylperoxy) butane; 1,1-bis (t-butylperoxy) cyclohexane; , 1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane; t-butylperoxybenzoate; benzoyl peroxide; Luperoxyacetate; 2,5-dimethyl-2,5-bis (tertiarybutylperoxy) hexyne-3; 1,1-bis (tertiarybutylperoxy) -3,3,5-trimethylcyclohexane; 1-bis (tert-butylperoxy) cyclohexane; methyl ethyl ketone peroxide; 2,5-dimethylhexyl-2,5-bisperoxybenzoate; tert-butyl hydroperoxide; p-menthane hydroperoxide; p-chlorobenzoyl Peroxides; tertiary butyl peroxyisobutyrate; hydroxyheptyl peroxide; chlorohexanone peroxide. These peroxides are used singly or in combination of two or more, and are usually used at a ratio of 5 parts by mass or less, preferably 0.5 to 5.0 parts by mass with respect to 100 parts by weight of EVA. .

  The organic peroxide is usually kneaded with EVA using an extruder, a roll mill or the like, but may be dissolved in an organic solvent, a plasticizer, a vinyl monomer or the like and added to the EVA film by an impregnation method.

  Various acryloxy group or methacryloxy group and allyl group-containing compounds can be added to improve EVA physical properties (mechanical strength, optical properties, adhesiveness, weather resistance, whitening resistance, crosslinking speed, etc.). . As the compound used for this purpose, acrylic acid or methacrylic acid derivatives, for example, esters and amides thereof are the most common. As the ester residue, in addition to alkyl groups such as methyl, ethyl, dodecyl, stearyl, lauryl, cyclohexyl groups , Tetrahydrofurfuryl group, aminoethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 3-chloro-2-hydroxypropyl group and the like. Further, esters with polyfunctional alcohols such as ethylene glycol, triethylene glycol, polyethylene glycol, trimethylolpropane, and pentaerythritol can also be used. A typical amide is diacetone acrylamide.

  Examples thereof include polyfunctional esters such as acrylic or methacrylic acid esters such as trimethylolpropane, pentaerythritol, glycerin, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl maleate, etc. Examples include allyl group-containing compounds. These are used alone or in combination of two or more, and are usually used in an amount of 0.1 to 2 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of EVA. .

  When EVA is crosslinked by light, a photosensitizer is usually used in an amount of 5 parts by mass or less, preferably 0.1 to 3.0 parts by mass based on 100 parts by mass of EVA instead of the peroxide.

  In this case, usable photosensitizers include, for example, benzoin, benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, dibenzyl, 5-nitroacenaphthene, hexachlorocyclopentadiene, p-nitrodiphenyl. , P-nitroaniline, 2,4,6-trinitroaniline, 1,2-benzanthraquinone, 3-methyl-1,3-diaza-1,9-benzanthrone, and the like. Alternatively, two or more types can be mixed and used.

  Moreover, a silane coupling agent is used in combination as an adhesion promoter. As this silane coupling agent, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycid Xylpropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- β (aminoethyl) -γ-aminopropyltrimethoxysilane and the like can be mentioned.

  The silane coupling agent is generally used in an amount of 0.001 to 10 parts by mass, preferably 0.001 to 5 parts by mass, based on 100 parts by mass of EVA, and one or more types are mixed and used.

  In addition, the EVA adhesive layer may contain a small amount of an ultraviolet absorber, an infrared absorber, an anti-aging agent, a paint processing aid, a colorant, etc., and in some cases, carbon black, hydrophobic silica. A small amount of a filler such as calcium carbonate may be included. Moreover, the transparent adhesive layer of this invention can also be suitably contained, such as a ultraviolet absorber, an infrared absorber, an anti-aging agent.

  The adhesive layer (or transparent pressure-sensitive adhesive layer) is, for example, mixed with EVA and the above-mentioned additives, kneaded with an extruder, roll, etc., and then predetermined by a film forming method such as calendar, roll, T-die extrusion, inflation, etc. It is manufactured by forming a sheet into a shape of

  A protective layer may be provided on the antireflection layer. The protective layer is preferably formed in the same manner as the hard coat layer.

  The material of the release sheet provided on the transparent adhesive layer is preferably a transparent polymer having a glass transition temperature of 50 ° C. or higher. Examples of such a material include polyesters such as polyethylene terephthalate, polycyclohexylene terephthalate, and polyethylene naphthalate. In addition to polyamide resins such as nylon resins, nylon 46, modified nylon 6T, nylon MXD6, polyphthalamide, ketone resins such as polyphenylene sulfide and polythioether sulfone, and sulfone resins such as polysulfone and polyether sulfone, Mainly composed of polymers such as polyether nitrile, polyarylate, polyether imide, polyamide imide, polycarbonate, polymethyl methacrylate, triacetyl cellulose, polystyrene, polyvinyl chloride That the resin can be used. Of these, polycarbonate, polymethyl methacrylate, polyvinyl chloride, polystyrene, and polyethylene terephthalate can be suitably used. The thickness is preferably 10 to 200 μm, particularly preferably 30 to 100 μm.

  The antireflection / near-infrared blocking filter (optical filter) of the present invention is provided with, for example, an intermediate layer, a hard coat layer, and an antireflection layer sequentially on one surface of a long transparent film, and then the other of the transparent film It is obtained by producing a long laminate by providing a near-infrared absorbing layer and, if necessary, a transparent pressure-sensitive adhesive layer on the surface, and cutting it.

  As a coating machine used when applying (applying) each layer to a long transparent film, a slit die, a lip direct, a lip reverse, or the like can be used. When both surfaces are applied simultaneously, a double-sided simultaneous coating machine in which lip dies are arranged on both sides is generally used.

  The optical filter of the present invention used for the optical filter for PDP of the present invention thus obtained is used as it is or in combination with another filter by being bonded to the surface of the image display glass plate of the PDP. FIG. 2 shows a state where the optical filter of the present invention is bonded to the surface of the image display glass plate of the PDP. The optical filter of the present invention is adhered to the surface of the display surface 20 of the display panel via the transparent adhesive layer 16, whereby the intermediate layer 12, the hard coat layer 13, and the low refractive index are formed on one surface of the transparent substrate 11. The rate layer 14 is sequentially laminated, and an optical filter on which the near-infrared absorbing layer 15 is laminated is provided on the surface of the display surface 20 of the display panel on the other surface of the transparent substrate 11.

  Since the PDP display device of the present invention normally uses a single plastic film as the transparent substrate, the optical filter of the present invention can be directly bonded to the surface of the glass plate, which reduces the weight of the PDP itself. , Can contribute to reduction in thickness and cost. Compared with the case where a front plate made of a transparent molded body is installed on the front side of the PDP, an air layer having a low refractive index can be eliminated between the PDP and the PDP filter, so that visible light reflection due to interface reflection can be achieved. Problems such as an increase in rate and double reflection can be solved, and the visibility of the PDP can be further improved.

  Furthermore, as described above, the optical filter of the present invention is excellent in the antireflection effect and near-infrared shielding, and has no interference fringes. Therefore, it is possible to provide a PDP that is easy to see and exhibits a natural color tone.

  The following examples further illustrate the present invention. The present invention is not limited by the following examples.

[Example 1]
Production of Antireflection / Near-Infrared Cutoff Filter of the Present Invention PET film (refractive index 1.65, 150 μm thickness) containing 5% by mass of an ultraviolet absorber (CYASORB UV-3638, manufactured by CYTEC) as a transparent substrate Immediately after the film formation, an acrylic resin modified with sulfur was cast on this PET film, and this was rolled and bonded to form an intermediate layer (intermediate refractive index layer) having a refractive index of 1.57 and a thickness of 87 nm. .

Next, 75 parts by mass of dipentaerythritol hexaacrylate (DPHA) (trade name DPHA, manufactured by Nippon Kayaku Co., Ltd.) as a polyfunctional acrylate monomer, 25 parts by mass of zirconia, 100 parts by mass of MEK, 100 parts by mass of toluene, polymerization start A coating solution containing 4 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure 184) was prepared as an agent, and applied onto the intermediate layer described above. Next, after drying at 80 ° C. for about 1 minute, it was cured by ultraviolet irradiation (light quantity 200 mJ / cm ² ) to form a hard coat layer (refractive index 1.54, thickness 3 μm).

  On this, the coating liquid containing a fluororesin layer (refractive index 1.43, thickness 90nm) was apply | coated and dried (80 degreeC, 5 minutes), and the low refractive index layer was formed.

Then the following formulation:
Polymethyl methacrylate 30 parts by mass TAP-2 (manufactured by Yamada Chemical Co., Ltd.) 0.4 parts by mass Plast Red 8380 (manufactured by Arimoto Chemical Industry Co., Ltd.) 0.1 parts by mass CIR-1085 (Nippon Carlit Co., Ltd.) Manufactured) 1.3 parts by weight IR-10A (manufactured by Nippon Shokubai Co., Ltd.) 0.6 parts by weight Methyl ethyl ketone 152 parts by weight Methyl isobutyl ketone 18 parts by weight of a coating solution was mixed on the back surface of the PET film. It was applied by a gravure coating method and dried in an oven at 80 ° C. for 5 minutes. Thereby, a near-infrared absorbing layer (having a color tone correction function) having a thickness of 5 μm was formed on the PET film.

  Thus, an antireflection / near-infrared shielding filter for a PDP optical filter was produced.

[Example 2]
In Example 1, on the near-infrared absorbing layer,
The following formulation:
SK Dyne 1811L (manufactured by Soken Chemical Co., Ltd.) 100 parts by mass Curing agent L-45 (manufactured by Soken Chemical Co., Ltd.) 0.45 parts by mass Toluene 15 parts by mass Ethyl acetate 4 parts by mass Is applied using a bar coater and dried in an oven at 80 ° C. for 5 minutes, thereby forming a transparent adhesive layer having a thickness of 25 μm on the near infrared absorbing layer. A cutoff filter was produced.

[Example 3]
In Example 2, an anti-reflection / near-infrared blocking filter was prepared in the same manner except that 0.013 g of varifast black 3808 (manufactured by Orient Chemical Co., Ltd.) was further added to the formulation of the coating solution for the transparent adhesive layer. .

[Example 4]
In Example 2, anti-reflection / near-infrared shielding was carried out in the same manner except that 0.027 g of Eisen / Spiron / Black MH Special (Hodogaya Chemical Co., Ltd.) was added to the formulation of the coating solution for the transparent adhesive layer. A filter was produced.

[Comparative Example 1]
An antireflection / near infrared blocking filter was produced in the same manner as in Example 1 except that the near infrared absorbing layer was not provided and the thickness of the intermediate layer was changed from 87 nm to 40 nm.

[Comparative Example 2]
An antireflection / near-infrared shielding filter was prepared in the same manner as in Example 1 except that a PET film containing no UV absorber was used instead of the UV absorber-containing PET film.

[Comparative Example 3]
In Example 2, the anti-reflective / near surface was changed in the same manner except that the refractive index of the intermediate layer was changed from 1.57 to 1.51 by adjusting the sulfur content of the sulfur-modified acrylic resin used in the intermediate layer. An infrared blocking filter was produced.

[Reference Example 1]
An antireflection / near infrared blocking filter was produced in the same manner as in Example 1 except that the composition of the coating solution for the near infrared absorbing layer was changed to the following.

Formula:
Polymethyl methacrylate 30 parts by mass TAP-2 (manufactured by Yamada Chemical Co., Ltd.) 0.4 parts by mass Plast Red 8380 (manufactured by Arimoto Chemical Industry Co., Ltd.) 0.1 parts by mass CIR-1085 (Nippon Carlit Co., Ltd.) 1.3 parts by mass IR-10A (manufactured by Nippon Shokubai Co., Ltd.) 0.6 parts by mass Bis (4-t-butyl-1,2-dithiophenolate)
Copper-tetra-n-butylammonium 0.3 mass part Methyl ethyl ketone 152 mass parts Methyl isobutyl ketone 18 mass parts

  Furthermore, the obtained antireflection / near-infrared shielding filter (optical filter) was bonded to a glass plate to produce the following display filter for evaluation. Each characteristic was evaluated.

[Evaluation of optical filter]
(1) Reflectance (low refractive index layer)
A sample was prepared by rubbing the back surface with sandpaper and applying black magic so that reflection of the back surface did not occur, and using a spectrophotometer (U-4000 type, manufactured by Hitachi, Ltd.), wavelength: 380 to 700 nm. The minimum surface reflectance of regular reflection at 5 ° incident light was obtained.
The evaluation was performed in two steps: ○: when the minimum reflectance was 2.0% or less, and x: when the minimum reflectance exceeded 2.0%.
(2) Interference fringes The resulting optical filter is a room that uses a three-wavelength fluorescent lamp (product name: FHF32EX-N, manufactured by Toshiba Corporation) as a ceiling lamp, and an antireflection filter surface is provided on a smooth wall surface. Installed to be inside. The degree of interference fringes (oil stain) generated by illumination of a three-wavelength fluorescent lamp was visually evaluated.
The evaluation was performed in three stages: ○: conspicuous interference fringes are hardly visible, Δ: conspicuous interference fringes are slightly visible, and X: conspicuous interference fringes are clearly visible.
(3) Light transmittance Using a spectrophotometer (manufactured by Hitachi, Ltd., U-4000 type), irradiating light of a specific wavelength from the near infrared absorption layer side in a wavelength range of 350 to 1250 nm, The air permeability is measured as a reference value (blank).
(4) Durability The obtained optical filter is allowed to stand for 500 hours in an atmosphere at a temperature of 60 ° C. and a humidity of 90%, and then the light transmittance of (1) is measured. Durability is evaluated by the difference in transmittance before and after the accelerated test.
That is, the evaluation was performed in two stages: ◯: when the change in transmittance was 2.0% or less, x: when the change in transmittance exceeded 2.0%.

  The results are shown in Table 1 below.

  From the above results, when the optical filters of Examples 1 to 4 having the specific transparent substrate, intermediate layer, hard coat layer, and near infrared absorption layer of the present invention are used as a display filter, reflectance, interference fringes, etc. It is clear that the reflection characteristics are good and the durability is excellent. Moreover, when the optical filter of Example 3 and 4 provided with the specific transparent adhesive layer of this invention was affixed on the display surface of PDP, the image with favorable contrast and very easy to see was obtained.

FIG. 1 is a cross-sectional view of an example of a preferred embodiment of the antireflection / near infrared blocking filter of the present invention. It is sectional drawing which shows the state by which the reflection prevention and near-infrared shielding filter of this invention was bonded together on the surface of the image display glass plate of PDP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Transparent substrate 12 Intermediate | middle layer 13 Hard-coat layer 14 Low refractive index layer 15 Near-infrared absorption layer 16 Transparent adhesive layer 20 Display surface of a display panel

Claims (14)

A low refractive index layer having a refractive index lower than that of the intermediate layer, the hard coat layer, and the hard coat layer is provided in this order on one surface of the transparent substrate, and a near-infrared absorbing layer is provided on the other surface of the transparent substrate. An anti-reflection and near-infrared blocking filter provided,
The following formulas (1) to (4):
n ₁ > n ₂ > n ₃ (1)
| N ₂ − (n ₁ + n ₃ ) /2|≦0.07 (2)
1.56 ≦ n ₁ ≦ 1.71 (3)
1.50 ≦ n ₂ ≦ 1.70 (4)
(Where n ₁ is the refractive index of the transparent substrate, n ₂ is the refractive index of the intermediate layer, and n ₃ is the refractive index of the hard coat layer)
The filling,
The thickness d (nm) of the intermediate layer is in the range of 65 to 103 nm, and one or more dyes contained in the near infrared absorption layer have absorption maximums in the wavelength range of 800 to 1200 nm and the wavelength range of 580 to 605 nm. An anti-reflection / near-infrared shielding filter used for an optical filter for a plasma display panel.   The anti-reflection / near-infrared shielding filter according to claim 1, wherein a transparent adhesive layer is provided on the near-infrared absorbing layer.   The anti-reflection / near-infrared shielding filter according to claim 2, wherein the transparent adhesive layer contains a polymer and a dye for reducing visible light transmittance.   The anti-reflection / near-infrared shielding filter according to claim 3, wherein the transparent pressure-sensitive adhesive layer contains 0.01 to 0.5% by mass of a dye for reducing visible light transmittance with respect to the polymer.   The one or more dyes contained in the near-infrared absorbing layer are composed of one or more dyes having an absorption maximum in the wavelength range of 800 to 1200 nm and one or more dyes having an absorption maximum in the wavelength range of 580 to 605 nm. Item 5. The antireflection / near-infrared shielding filter according to any one of Items 1 to 4.   The anti-reflective / near-infrared shielding filter according to claim 6, comprising a diimmonium salt-based dye as the dye contained in the near-infrared absorbing layer.   The anti-reflection / near-infrared shielding filter according to claim 6, wherein the near-infrared absorbing layer does not contain a nickel complex compound.   The antireflection / near-infrared shielding filter according to any one of claims 1 to 7, wherein the intermediate layer, the hard coat layer, and the low refractive index layer are all coating layers. The antireflective / near-infrared blocking filter according to claim 1, wherein the hard coat layer has a refractive index n ₃ in the range of 1.49 to 1.60. PET film is used as the transparent substrate, antireflection-near infrared cutoff filter according to any one of claims 1-9 refractive index n ₂ of the intermediate layer is 1.65 or less of the value.   The antireflection / near-infrared shielding filter according to any one of claims 1 to 10, wherein the hard coat layer is a cured layer of a composition containing an ultraviolet curable resin.   The antireflection / near-infrared blocking filter according to any one of claims 1 to 11, wherein the transparent substrate contains an ultraviolet absorber.   An optical filter for a plasma display panel, comprising the antireflection / near-infrared shielding filter according to claim 1.   14. A plasma display panel, wherein the optical filter for a plasma display panel according to claim 13 is bonded to the surface of an image display glass plate.

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