JP2000338325A - Optical filter and antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter having a proper color compensation function by constituting a filter layer containing fine particles and incorporating a dye as adsorbed on the surface of the fine particles into the filter layer. SOLUTION: The filter has a filter layer containing a dye and a polymer binder on a transparent supporting body, and the filter layer contains fine particles and a dye as adsorbed on the surface of the fine particles. For example, an antireflection film (an optical filter having an antireflection layer) has a layer structure in the order of a filter layer 2, a transparent supporting body 1 and a low refractive index layer 3. In this case, the layers satisfy the relation of (refractive index of the low refractive index layer 3) < (refractive index of the transparent supporting body 1). Or, the filter has a layer structure in the order of a filter layer 2, a transparent supporting body 1, a hard coating layer 4, a medium refractive index layer 6, a high refractive index layer 5, and a low refractive index layer 3. In this case, the layers satisfy the relation of refractive indices of the layers s satisfy the relation of (refractive index of the low refractive index layer 3) < (refractive index of the transparent supporting body 1) < (refractive index of the medium refractive index layer 6) < (refractive index of the high refractive index layer 5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical filter having a transparent support and a filter layer. Also,
The present invention relates to a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display (CRT), a fluorescent display tube, and a surface of an image display device such as a field emission display. The present invention also relates to an antireflection film attached for antireflection or improving color reproducibility.

[0002]

2. Description of the Related Art A liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display (CRT),
2. Description of the Related Art An image display device such as a fluorescent display tube or a field emission display displays a color image by a combination of light of three primary colors of red, blue and green in principle. However, it is very difficult (practically impossible) to make light for display ideal three primary colors. For example, in a plasma display panel (PDP), it is known that extra light (wavelength in the range of 560 to 620 nm) is included in light emission from the three primary color phosphors. Therefore, it has been proposed to perform color correction using an optical filter that absorbs light of a specific wavelength in order to correct the color balance of display colors. Japanese Patent Laid-Open No. 58-153 discloses color correction using an optical filter.
No. 904, No. 60-118748, No. 60-1874
No. 9, No. 61-188501, JP-A-3-23198
No. 8, No. 5-203804, No. 5-205564,
No. 7-307133, No. 9-145918, No. 9-
These are described in JP-A Nos. 306366 and 10-26704.

[0003] In addition to the color correction, the image display device also needs to prevent reflection. That is, the image display device has a problem that the contrast is reduced due to the background being reflected on the display. As a solution to this problem,
Various antireflection films have been proposed. The antireflection functional layers of the antireflection films proposed so far can be classified into vapor deposition layers and coating layers. Although the vapor deposition layer is superior from the viewpoint of optical functions, the coating layer has an advantage that it is easy to manufacture.
The vapor deposition layer has been used for a long time as an antireflection film for lenses such as glasses and cameras. The deposition layer is a vacuum deposition method,
It is formed by a sputtering method, an ion plating method, a CVD method or a PVD method. The coating layer is generally
It is formed by applying fine particles and a binder. Coating layers are described in JP-A-59-49501 and JP-A-59-50.
No. 401, 60-59250, JP-A-7-4852
No. 7 describes each.

It is also conceivable to incorporate an antireflection function into the optical filter. The above-mentioned JP-A-61-188.
No. 501, JP-A-5-205643 and 9-1459
No. 18, No. 9-306366, and No. 10-26704 disclose optical filters having an antireflection function incorporated therein. JP-A-61-188501, JP-A-5-205643, JP-A-9-145918 and JP-A-9-145918
In the optical filter described in each publication of 306366,
A dye or a pigment is added to the transparent support so that the support functions as a filter. JP-A-10-26704
In the optical filter described in the publication, a hard coat layer (surface hardened layer) provided between the transparent support and the antireflection layer
And the hard coat layer functions as a filter.

[0005]

If the transparent support or the hard coat layer is colored, the transparent support or the hard coat layer functions as a filter. However, the types of dyes that can be added to the transparent support and the hard coat layer are very limited. The transparent support is made from plastic or glass (usually plastic). The dye to be added to the transparent support is required to have a very high heat resistance enough to withstand the temperature during the production of the support. The hard coat layer is generally a layer containing a crosslinked polymer. The crosslinking reaction of the polymer is carried out after the application of the layer. Under the reaction conditions for crosslinking, there are many dyes that fade. The dye which can be added to the transparent support or the hard coat layer has a broad peak at the absorption maximum (broad half width), and it is difficult to perform appropriate color correction corresponding to the image display device. Methine dyes developed in the field of silver halide photography are compounds having various absorption spectral properties. It is known that the use of a methine dye in an associated state reduces the half width. However, methine dyes have been developed on the premise that they are added to a layer of a silver halide photographic material, and when a methine dye is added to a transparent support or a hard coat layer, a problem of fading occurs.

The inventor of the present invention added a dye aggregate to a polymer layer that can be formed under mild conditions, instead of a transparent support or a hard coat layer, which has many restrictions on the types of dyes that can be used, and uses the polymer layer as a filter layer. We considered making it work. However, the polymer layer has a weaker dye protection function than the transparent support or the hard coat layer. In order to add a dye to the polymer layer, it is necessary to improve the stability and durability (particularly, light fastness) of the aggregate of the dye. Some dyes do not readily form an aggregate. An object of the present invention is to provide an optical filter having an appropriate color correction function. Another object of the present invention is to provide an antireflection film having an appropriate color correction function in addition to the antireflection function.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide the following optical filters (1) to (4) and the following (5) to (5).
This was achieved by the antireflection film of (12). (1) An optical filter having a filter layer containing a dye and a polymer binder on a transparent support, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. An optical filter, comprising: (2) The optical filter according to (1), which is for a plasma display panel. (3) The optical filter according to (1), wherein the fine particles are inorganic fine particles having an average particle size of 0.005 to 20 μm. (4) The optical filter according to (1), wherein the dye adsorbed on the surface of the fine particles has an absorption maximum in a wavelength region of 560 to 620 nm.

(5) A filter layer containing a dye and a polymer binder, a transparent support, and a low refractive index layer having a refractive index lower than that of the transparent support are the antireflection films laminated in this order. An antireflection film, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. (6) The antireflection film according to (5), which is for a plasma display panel. (7) The antireflection film according to (5), wherein the fine particles are inorganic fine particles having an average particle size of 0.005 to 20 μm. (8) The antireflection film according to (5), wherein the dye adsorbed on the surface of the fine particles has an absorption maximum in a wavelength region of 560 to 620 nm.

(9) An anti-reflection film in which a transparent support, a filter layer containing a dye and a polymer binder, and a low refractive index layer having a refractive index lower than that of the transparent support are laminated in this order. An antireflection film, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. (10) The antireflection film according to (9), which is for a plasma display panel. (11) The fine particles have an average particle size of 0.005 to 20 μm
The antireflection film according to (9), which is an inorganic fine particle. (12) The antireflection film according to (9), wherein the dye adsorbed on the surface of the fine particles has an absorption maximum in a wavelength region of 560 to 620 nm.

[0010]

When the dye in the associated state is used, the absorption maximum of the dye can be easily adjusted, and an absorption characteristic with a narrow half width suitable for an image display device can be obtained. However, dyes in an associated state added to the filter layer generally have a problem in stability (particularly light resistance). Some dyes do not readily form an aggregate. As a result of research, the present inventor has succeeded in obtaining an effect similar to that of a dye in an associated state, that is, an absorption characteristic in which a peak at an absorption maximum is sharp (a half width is narrow) by adsorbing the dye on the surface of the fine particles. did. The dye adsorbed on the surface of the fine particles is more stable than the dye in the associated state. Even dyes that do not form an association state can be relatively easily adsorbed on the surface of the fine particles. Therefore, in the optical filter of the present invention, a dye having a required absorption polarity can be used without any particular limitation. As a result, the optical filter and the antireflection film of the invention have an appropriate color correction function according to the type of the image display device.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical layer structure of an antireflection film (optical filter provided with an antireflection layer) will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a layer configuration of an antireflection film in which a filter layer is provided on the side opposite to the transparent support from the antireflection layer. The embodiment shown in FIG. 1A includes a filter layer (2), a transparent support (1), and a low refractive index layer (3).
In the following order. The transparent support (1) and the low refractive index layer (3) have a refractive index satisfying the following relationship. Refractive index of low refractive index layer <refractive index of transparent support

The embodiment shown in FIG. 1B has a layer structure in the order of a filter layer (2), a transparent support (1), a hard coat layer (4), and a low refractive index layer (3). FIG. 1 (c)
Has a layer structure of a filter layer (2), a transparent support (1), a hard coat layer (4), a high refractive index layer (5), and a low refractive index layer (3). The transparent support (1), the low refractive index layer (3) and the high refractive index layer (5)
It has a refractive index satisfying the following relationship. The refractive index of the low refractive index layer <the refractive index of the transparent support <the refractive index of the high refractive index layer In the embodiment shown in FIG. 1D, the filter layer (2), the transparent support (1), and the hard coat layer ( 4), a middle refractive index layer (6), a high refractive index layer (5), and a low refractive index layer (3). The transparent support (1), the low refractive index layer (3), the high refractive index layer (5) and the medium refractive index layer (6)
It has a refractive index satisfying the following relationship. Refractive index of low refractive index layer <refractive index of transparent support <refractive index of medium refractive index layer <refractive index of high refractive index layer

FIG. 2 is a schematic sectional view showing a layer structure of an antireflection film in which a filter layer and an antireflection layer are provided on the same side of a transparent support. The embodiment shown in FIG. 2A has a layer structure in the order of the transparent support (1), the filter layer (2), and the low refractive index layer (3). The relationship between the refractive index of the transparent support (1) and the refractive index of the low refractive index layer (3) is the same as that of FIG.
The embodiment shown in FIG. 2B has a layer structure in the order of the transparent support (1), the filter layer (2), the hard coat layer (4), and the low refractive index layer (3). The mode shown in FIG. 2C is a transparent support (1), a filter layer (2), a hard coat layer (4), a high refractive index layer (5), and a low refractive index layer (3).
In the following order. The relationship between the refractive indices of the transparent support (1), the low refractive index layer (3) and the high refractive index layer (5) is the same as that in FIG. The mode shown in FIG.
The transparent support (1), the filter layer (2), the hard coat layer (4), the medium refractive index layer (6), the high refractive index layer (5), and the low refractive index layer (3) have a layer structure in this order. . The relationship among the refractive indices of the transparent support (1), the low refractive index layer (3), the high refractive index layer (5) and the middle refractive index layer (6) is the same as that in FIG.

(Transparent Support) Examples of materials for forming the transparent support include cellulose esters (eg, diacetyl cellulose, triacetyl cellulose (TAC), propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, nitrocellulose), Polyamide, polycarbonate, polyester (eg, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, poly-1,4-cyclohexane dimethylene terephthalate, polyethylene-1,2-diphenoxyethane-4,4′-dicarboxylate, poly Butylene terephthalate), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polyethylene, polypropylene, polymethylpentene), polymethylmethacrylate , Syndiotactic polystyrene, polysulfone, polyethersulfone, polyetherketone, polyetherimide and polyoxyethylene. Triacetyl cellulose, polycarbonate and polyethylene terephthalate are preferred. The transmittance of the transparent support is preferably 80% or more,
More preferably, it is 86% or more. Haze is 2
%, More preferably 1% or less. The refractive index is preferably from 1.45 to 1.70.

An infrared absorber or an ultraviolet absorber may be added to the transparent support. The amount of the infrared absorbing agent or the ultraviolet absorbing agent is 0.01 to 20% by weight of the transparent support.
And more preferably 0.05 to 10% by weight. Further, as a slipping agent, particles of an inert inorganic compound may be added to the transparent support. Examples of inorganic compounds include SiO ₂ , TiO ₂ , BaSO ₄ , Ca
Includes CO ₃ , talc and kaolin. The transparent support may be subjected to a surface treatment. Examples of the surface treatment include chemical treatment, mechanical treatment, corona discharge treatment, flame treatment, ultraviolet irradiation treatment, high frequency treatment, glow discharge treatment, active plasma treatment, laser treatment, mixed acid treatment and ozone oxidation treatment. Glow discharge treatment, ultraviolet irradiation treatment, corona discharge treatment and flame treatment are preferred, and glow discharge treatment and ultraviolet treatment are more preferred. Further, an undercoat layer for strengthening the adhesion with the upper layer may be provided.

(Filter Layer) The thickness of the filter layer is preferably 0.1 μm to 5 cm. The filter layer preferably has an absorption maximum in a wavelength range of 560 to 620 nm (between green and red). 560 to 6
The transmittance of the filter layer at the absorption maximum in the wavelength region of 20 nm is preferably in the range of 0.01 to 80%, more preferably in the range of 0.1 to 60%. The absorption maximum in the wavelength range of 560 to 620 nm has a function of selectively cutting the sub-band that reduces the color purity of the red phosphor. In a plasma display panel, 595 n emitted by excitation of neon gas
Unnecessary light emission near m can also be cut. By setting the absorption maximum as described above, light can be selectively cut without adversely affecting the color tone of the green phosphor. 560 to 6 to further reduce the effect of the green phosphor on the color tone
The absorption maximum in the wavelength region of 20 nm is preferably sharp. Specifically, at the absorption maximum in the wavelength region of 560 to 620 nm, the half width value (width of the wavelength region showing half the absorbance of the absorbance of the absorption maximum) is preferably 10 to 120 nm, and more preferably 15 to 100 nm. More preferably, it is more preferably from 20 to 70 nm, and most preferably from 30 to 50 nm.

The filter layer contains a dye and a polymer binder. In the present invention, the dye is used in a state of being adsorbed on the surface of the fine particles. For this purpose, the dye preferably has an adsorptive group (eg, anionic group, cationic group, polar group) or a hetero atom (eg, nitrogen, oxygen, sulfur) in the molecule. However, the dye generally has an adsorptive group or a hetero atom. Therefore, in the present invention, various dyes can be used by adsorbing them on the surface of the fine particles. Dyes include methine dyes, azo dyes, azomethine dyes, azine dyes, naphthoquinone dyes, anthraquinone dyes, triphenylmethane dyes and diphenyl dyes. Methine dyes are particularly preferred.

[0018] Methine dyes can be classified into cyanine dyes, merocyanine dyes, arylidene dyes, styryl dyes and oxonol dyes. Each methine dye is defined by the following formula. Cyanine dye: Bs = Lo-Bo Merocyanine dye: Bs = Le = Ak arylidene dye: Ak = Lo-Ar styryl dye: Bo-Le-Ar Oxonol dye: Ak = Lo-Ae In the formula, Bs is a basic nucleus. Yes; Bo is an onium of a basic nucleus; Ak is a keto-type acidic nucleus;
Is an enol-type acidic nucleus; Ar is an aromatic nucleus; Lo is a methine chain consisting of an odd number of methines;
Le is a methine chain composed of an even number of methines.

It is preferable to use a cyanine dye or a merocyanine dye, and it is particularly preferable to use a cyanine dye. For methine dyes, see FM Harmer, Heterocyclic Compounds-Cyanine Dyes and Reused Compounds.
lated Compounds), John Wiley and Sons, New York, London, 1964; DM Stumer
rmer), Heterocyclic Compounds-Special Topics in H
eterocyclicChemistry) ", Chapter 18, Section 14, 482
On page 515.

In the present invention, the dye is used by adsorbing it on fine particles. The fine particles are preferably inorganic fine particles.
Examples of inorganic fine particles include silica bell particles, alumina particles,
Talc, calcium silicate particles, diatomaceous earth, silver halide (silver chloride, silver bromide, silver iodide) particles, anionic layered inorganic compound particles (described in JP-A-10-104808),
Includes clay minerals (eg, bentonite, hectonite, montmorillonite), synthetic mica and synthetic smectite. Preferably, the synthetic mica is swellable. The silver halide grains are preferably non-photosensitive. Non-photosensitive silver halide is described in JP-A-11-65013. It is particularly preferable to use non-photosensitive silver halide grains. The average particle size of the fine particles is 0.005
To 20 μm, preferably 0.005 to 1 μm.
μm, more preferably 0.005 to 0.5 μm.
Most preferably, it is 1 μm. There is no particular limitation on the shape of the fine particles. The ratio between the dye and the fine particles is preferably from 2 to 0.001, more preferably from 0.5 to 0.001, and more preferably from 0.1 to 0.001, by weight of the dye / fine particles. Is most preferred.

The dye adsorbed on the fine particles forms a so-called J band and thus shows a sharp absorption spectrum peak. For the J band of the dye, see the literature (eg, Ph.
otographic Science and Engineering Vol. 18, No. 32
3-335 (1974)). In the dye forming the J band, the absorption maximum moves to a longer wavelength side than the absorption maximum of the dye in a solution state. It is preferable that the dye adsorbed on the fine particles has its absorption maximum shifted to a longer wavelength side by 40 nm or more than the absorption maximum of the dye in a solution state. The movement of the absorption maximum is
The thickness is more preferably 45 nm or more, further preferably 50 nm or more, and most preferably 60 nm or more. The dye is relatively easily adsorbed on the surface of the fine particles (particularly, the inorganic fine particles). When silver halide grains are used as fine particles, a method of adsorbing a spectral sensitizing dye on the surface of silver halide grains, which is studied in the technical field of silver halide photographic materials, can be applied.
Two or more dyes adsorbed on the fine particles may be used in combination.

In addition to the dye adsorbed on the fine particles, another dye may be used in combination. The filter layer is made of 56
In addition to the absorption maximum in the wavelength region of 0 to 620 nm (between green and red), it is preferable to have the absorption maximum in the wavelength region of 500 to 550 nm (green). When the dye adsorbed on the fine particles is used in combination with another dye, the dye adsorbed on the fine particles has an absorption maximum in a wavelength region of 560 to 620 nm, and the other dye has an absorption maximum in a wavelength region of 500 to 550 nm. It preferably has an absorption maximum. 500 to 550
The transmittance at the absorption maximum in nm is preferably 30 to 85%. Examples of the dye having an absorption maximum in a wavelength region of 500 to 550 nm include a squarylium dye,
Triphenylmethane dye, arylidene dye, oxonol dye, azo dye, azomethine dye, anthraquinone dye, cyanine dye, merocyanine dye, benzylidene dye or xanthene dye are preferably used. These dyes are described in the specifications of U.S. Pat. Nos. 2,247,782, 3,471,293 and 3,379,533. Further, a pigment having an absorption maximum in a wavelength region of 500 to 550 nm may be used.

The wavelength range described above (500 to 550 nm)
And 560 to 620 nm). As such a dye, a near infrared absorbing dye can be used. As a near-infrared absorbing dye, a cyanine dye (JP-A-9-9689)
No. 1), metal chelate dyes, aminium dyes,
A diimonium dye, a quinone dye, a squarylium dye (described in JP-A-9-90547 and JP-A-10-204310) and various methine dyes can be used.
As for the near infrared absorbing dye, a coloring material, 61 [4] 215-
226 (1988) and Chemical Industries 43-53 (198).
May, 2006).

As the polymer binder for the filter layer, natural polymers (eg, gelatin, cellulose derivatives,
Alginic acid) or a synthetic polymer (eg, polymethyl methacrylate, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl chloride, styrene-butadiene copolymer, polystyrene, polycarbonate, water-soluble polyamide) can be used. Hydrophilic polymers (the above-mentioned natural polymers, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl alcohol, and water-soluble polyamide) are preferred, and gelatin is particularly preferred.

An anti-fading agent may be added to the filter layer. Examples of anti-fading agents that function as dye stabilizers include hydroquinone derivatives (US Pat. No. 3,935,016).
Nos. 3,982,944), hydroquinone diether derivatives (described in U.S. Pat. No. 4,254,216 and JP-A-55-21004), phenol derivatives (described in JP-A-54-145530),
Derivatives of spiroindane or methylenedioxybenzene (UK Patent Publications Nos. 2077455 and 2062888)
And the derivatives of chroman, spirochroman or coumaran (U.S. Pat. Nos. 3,432,300 and 3,573,050).
Nos. 3574627 and 3764337 and JP-A Nos. 52-152225 and 53-20327.
Nos. 53-17729 and 61-90156), hydroquinone monoether or paraaminophenol derivatives (UK Patent 1347556,
Nos. 2066975 and JP-B-54-12
337, JP-A-55-6321) and bisphenol derivatives (described in US Pat. No. 3,700,455 and JP-B-48-31625).

In order to improve the stability of the dye to light or heat, a metal complex (described in US Pat. No. 4,245,018 and JP-A-60-97353) may be used as an anti-fading agent. In order to further improve the light fastness of the dye, a singlet oxygen quencher may be used as an anti-fading agent. Examples of the singlet oxygen quencher include a nitroso compound (described in JP-A-2-300288), a diimmonium compound (described in US Pat. No. 4,656,612), a nickel complex (described in JP-A-4-146189), and antioxidant. Agent (European Patent Publication 820057A1)
Description).

(Undercoat layer) It is preferable to provide an undercoat layer between the transparent support and the filter layer. The undercoat layer is formed as a layer containing a polymer having a glass transition temperature of −60 ° C. to 60 ° C., a layer having a rough surface on the filter layer side, or a layer containing a polymer having an affinity for the polymer of the filter layer. An undercoat layer is provided on the surface of the transparent support on which the filter layer is not provided to improve the adhesion between the transparent support and a layer provided thereon (for example, an antireflection layer or a hard coat layer). Is also good. The undercoat layer may be provided to improve the affinity between the adhesive for bonding the antireflection film and the image forming apparatus and the antireflection film. The thickness of the undercoat layer is preferably 2 nm to 20 μm, more preferably 5 nm to 5 μm, and most preferably 50 nm to 5 μm.

The undercoat layer containing a polymer having a glass transition temperature of -60 to 60 ° C. adheres the transparent support and the filter layer due to the tackiness of the polymer. Glass transition temperature 2
Polymers at 5 ° C or lower include vinyl chloride, vinylidene chloride,
It can be obtained by polymerization or copolymerization of vinyl acetate, butadiene, neoprene, styrene, chloroprene, acrylate, methacrylate, acrylonitrile or methyl vinyl ether. The glass transition temperature is preferably 20 ° C. or lower, more preferably 15 ° C. or lower, further preferably 10 ° C. or lower, still more preferably 5 ° C. or lower, and further preferably 0 ° C. or lower. Is most preferred. The undercoat layer having a rough surface adheres the transparent support and the filter layer by forming a filter layer on the rough surface. The undercoat layer having a rough surface can be easily formed by applying a polymer latex. The average particle size of the latex is preferably 0.02 to 3 μm,
More preferably, it is 5 to 1 μm. Examples of polymers having an affinity for the binder polymer of the filter layer include acrylic resins, cellulose derivatives, gelatin, casein, starch, polyvinyl alcohol, soluble nylon, and polymer latex. Two or more undercoat layers may be provided. The undercoat layer may contain a solvent for swelling the transparent support, a matting agent, a surfactant, an antistatic agent, a coating aid and a hardener.

(Anti-reflection layer) As an anti-reflection function of the anti-reflection layer, it is preferable that the regular reflectance is 3% or less.
More preferably, it is 1.8% or less. When providing an antireflection layer, a low refractive index layer is essential. The refractive index of the low refractive index layer is lower than the refractive index of the transparent support. The low refractive index layer preferably has a refractive index of 1.20 to 1.55, more preferably 1.30 to 1.55. The thickness of the low refractive index layer is preferably from 50 to 400 nm, more preferably from 50 to 200 nm. The low refractive index layer is a layer made of a fluorine-containing polymer having a low refractive index (Japanese Patent Application Laid-Open No. 57-34526,
No. 130103, No. 6-115023, No. 8-313
702, 7-168004), and a layer obtained by a sol-gel method (JP-A-5-208811,
JP-A-6-299091 and JP-A-7-168003) or a layer containing fine particles (JP-B-60-5925).
No. 0, JP-A-5-13021, JP-A-6-56478,
7-92306 and 9-288201). In the layer containing fine particles, voids can be formed in the low refractive index layer as microvoids between the fine particles or in the fine particles. The layer containing the fine particles preferably has a porosity of 3 to 50% by volume, more preferably 5 to 35% by volume.

In order to prevent reflection in a wide wavelength range,
It is preferable to laminate a layer having a high refractive index (middle / high refractive index layer) in addition to the low refractive index layer. The high refractive index layer preferably has a refractive index of 1.65 to 2.40.
More preferably, it is 70 to 2.20. The refractive index of the middle refractive index layer is adjusted to be an intermediate value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably from 1.50 to 1.90. The thickness of the middle / high refractive index layer is preferably from 5 nm to 100 μm, more preferably from 10 nm to 10 μm, and most preferably from 30 nm to 1 μm. The haze of the middle / high refractive index layer is preferably 5% or less, more preferably 3% or less, and most preferably 1% or less. The middle / high refractive index layer can be formed using a polymer binder having a relatively high refractive index. Examples of high refractive index polymers include polystyrene, styrene copolymers, polycarbonates, melamine resins, phenolic resins, epoxy resins, and polyurethanes obtained by reacting cyclic (alicyclic or aromatic) isocyanates with polyols. .
Other polymers having a cyclic (aromatic, heterocyclic, alicyclic) group and polymers having a halogen atom other than fluorine as a substituent also have a high refractive index. A polymer may be formed by a polymerization reaction of a monomer capable of radical curing by introducing a double bond.

In order to obtain a higher refractive index, inorganic fine particles may be dispersed in a polymer binder. The refractive index of the inorganic fine particles is preferably from 1.80 to 2.80. The inorganic fine particles are preferably formed from a metal oxide or sulfide. Examples of metal oxides or sulfides include titanium dioxide (eg, rutile, rutile / anatase mixed crystal, anatase, amorphous structure), tin oxide, indium oxide, zinc oxide, zirconium oxide, and zinc sulfide. Titanium oxide, tin oxide and indium oxide are particularly preferred. The inorganic fine particles contain oxides or sulfides of these metals as main components and may further contain other elements. The main component means a component having the largest content (% by weight) among the components constituting the particles. Examples of other elements include Ti, Zr, Sn, Sb, Cu, Fe, Mn,
Pb, Cd, As, Cr, Hg, Zn, Al, Mg, S
i, P and S are included. Inorganic materials that are film-forming and can be dispersed in solvents or are themselves liquid, such as alkoxides of various elements, salts of organic acids, coordination compounds (eg, chelate compounds) combined with coordination compounds, activity The middle / high refractive index layer can be formed using an inorganic polymer.

The anti-reflection layer can provide the surface with an anti-glare function (a function of scattering incident light on the surface to prevent a scene around the film from shifting to the film surface). For example, by forming fine irregularities on the surface of a transparent film, and forming an antireflection layer on the surface, or after forming the antireflection layer, by forming irregularities on the surface with an embossing roll, an anti-glare function is obtained. be able to.
An antireflection layer having an antiglare function generally has a haze of 3 to 30%.

The surface resistance of the layer having the (electromagnetic wave shielding layer) electromagnetic wave shielding effect is preferably 0.1 to 500 [Omega / m ^2, more preferably in the range of 0.1 to 10 [Omega / m ^2. Since it is a layer provided on an optical filter or an antireflection film, the electromagnetic wave shielding layer is preferably transparent. A layer generally known as a transparent conductive layer can be used as the electromagnetic wave shielding layer. As the transparent conductive layer, a metal thin film or a metal oxide thin film is preferably used. As the metal of the metal thin film, a noble metal is preferable,
Gold, silver, palladium or alloys thereof are preferred, and alloys of gold and silver are particularly preferred. The silver content in the alloy is
It is preferably at least 60% by weight. As the metal oxide of the metal oxide thin film, SnO ₂ , ZnO, ITO and In ₂ O ₃ are preferable. A metal thin film and a metal oxide thin film may be stacked. When both are laminated, the metal thin film can be protected (prevented from oxidation) by the metal oxide thin film, and the visible light transmittance can be increased. As the metal oxide to be laminated with the metal thin film, a divalent to tetravalent metal oxide (eg, zirconium oxide, titanium oxide, magnesium oxide, silicon oxide, aluminum oxide) is preferable. Also, a thin film of a metal alkoxide compound can be laminated with a metal thin film. The metal oxide or metal alkoxide compound thin film can be laminated on both sides of the metal thin film. When laminating on both sides of the metal thin film, different types of thin films may be used. The thickness of the metal thin film is preferably from 4 to 40 nm, more preferably from 5 to 35 nm, and most preferably from 6 to 30 nm. The thickness of the metal oxide or metal alkoxide compound thin film is
It is preferably 20 to 300 nm, and 40 to 1 nm.
More preferably, it is 00 nm. The electromagnetic wave shielding layer can be formed by a sputtering method, a vacuum deposition method, an ion plating method, a plasma CVD method, a plasma PVD method, or a coating of particles of a metal or metal oxide.

(Infrared ray shielding layer)
It preferably has a shielding effect against near infrared rays having a wavelength of from about 1200 nm to 1200 nm. The infrared shielding layer can be formed of a resin mixture. Examples of the infrared shielding component in the resin mixture include copper (described in JP-A-6-118228), copper compounds and phosphorus compounds (JP-A-62-519).
No. 0), a copper compound or a thiourea compound (described in JP-A-6-73197) or a tungsten compound (described in U.S. Pat. No. 3,647,772). Instead of providing the infrared shielding layer, a resin mixture may be added to the transparent support. Note that the silver thin film described as the electromagnetic wave shielding layer also has an infrared shielding effect.

(Other Layers) The optical filter may be provided with a hard coat layer, a lubricating layer, an antifouling layer, an antistatic layer, an ultraviolet absorbing layer or an intermediate layer. The hard coat layer preferably contains a cross-linked polymer. The hard coat layer can be formed using an acrylic, urethane, or epoxy polymer, oligomer, or monomer (eg, an ultraviolet curable resin). The hard coat layer can also be formed from a silica-based material. A lubricating layer may be formed on the outermost surface of the optical filter. The lubricating layer has a function of imparting lubricity to the surface of the antireflection film and improving scratch resistance. The lubricating layer can be formed using polyorganosiloxane (eg, silicone oil), natural wax, petroleum wax, higher fatty acid metal salt, fluorine-based lubricant or a derivative thereof. The thickness of the lubrication layer is 2
It is preferably from 20 to 20 nm. The antifouling layer can be formed using a fluorine-containing polymer. The thickness of the antifouling layer is preferably from 2 to 100 nm, more preferably from 5 to 30 nm.

The antireflection layer (medium-refractive-index layer, high-refractive-index layer, low-refractive-index layer), filter layer, undercoat layer, hard coat layer, lubricating layer, and other layers are formed by a general coating method. Can be. Examples of the coating method include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, and an extrusion coating method using a hopper (described in US Pat. No. 2,681,294). Is included. Two or more layers may be formed by simultaneous coating. The simultaneous coating method is described in U.S. Pat.
No. 41898, No. 3508947, No. 3526528
Issue specifications and Yuji Harazaki, "Coating Engineering" 2
It is described on page 53 (published by Asakura Shoten in 1973).

(Use of Optical Filter) The optical filter is applied to an image display device such as a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), and a cathode ray tube display (CRT). . When the antireflection layer is provided, the antireflection layer is arranged such that the surface on which the low refractive index layer is not provided faces the image display surface of the image display device. When the optical filter of the present invention is used as an antireflection filter of a plasma display panel (PDP), a particularly remarkable effect is obtained. A plasma display panel (PDP) includes a gas, a glass substrate, an electrode, an electrode lead material, a thick film printing material, and a phosphor. There are two glass substrates, a front glass substrate and a rear glass substrate. An electrode and an insulating layer are formed on two glass substrates. A phosphor layer is further formed on the rear glass substrate. Two glass substrates are assembled, and gas is sealed between them. Plasma display panels (PDPs) are already commercially available. Regarding the plasma display panel, Japanese Patent Laid-Open No.
No. 43 and No. 9-306366.

[0038]

[Example 1] (Formation of undercoat layer) After corona treatment on both sides of a transparent polyethylene terephthalate film having a thickness of 175 µm,
One side was coated with a latex made of a styrene-butadiene copolymer to a thickness of 130 nm to form an undercoat layer.

(Formation of Second Undercoat Layer) On the undercoat layer,
A gelatin aqueous solution containing acetic acid and glutaraldehyde was applied to a thickness of 50 nm to form a second undercoat layer.

(Formation of Low Refractive Index Layer) Reactive Fluoropolymer (JN-7219, manufactured by Nippon Synthetic Rubber Co., Ltd.) 2.50
1.3 g of t-butanol was added to the resulting mixture, and the mixture was stirred at room temperature for 10 minutes and filtered with a polypropylene filter having a pore size of 1 μm. The obtained coating solution for a low refractive index layer is applied to the surface opposite to the undercoat surface of the transparent support using a bar coater so that the dry film thickness becomes 110 nm, and dried at 120 ° C. for 30 minutes. And cured to form a low refractive index layer.

(Formation of Filter Layer) The average particle size is 0.0
Preparation of non-photosensitive silver chloride fine grain emulsion of 18 μm
Fine grain emulsion of Examples of 1-165013 (1-1)
Methine dye (1) at the same time as adding an aqueous solution of silver nitrate and an aqueous solution of sodium chloride.
Was added (0.002 mol / L) to prepare silver chloride fine particles having the methine dye (1) adsorbed on the surface.

[0042]

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The obtained coating solution for a filter layer was applied onto the second undercoat layer so that the coating amount of the dye was 30 mg / m ^2, and dried at 120 ° C. for 10 minutes to form a filter layer. The optical filter was produced.

Example 2 Instead of the methine dye (1),
An optical filter was produced in the same manner as in Example 1 except that the following methine dye (2) was used.

[0045]

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Example 3 Instead of the methine dye (1),
An optical filter was produced in the same manner as in Example 1 except that the following methine dye (3) was used.

[0047]

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Comparative Example 1 Polyvinyl butyral (PV
3.0 g of B-3000K (manufactured by Denki Kagaku Kogyo KK) was dissolved in 80 g of chloroform, and 0.12 g of the following comparative dye (a) was dissolved in the obtained solution. After stirring the mixture for 30 minutes, it was filtered through a polypropylene filter having a pore size of 1 μm. Except using the obtained filter layer coating solution,
An optical filter was produced in the same manner as in Example 1.

[0049]

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Comparative Example 2 3.0 g of partially hydrolyzed polyvinyl acetate was dissolved in 80 g of isopropyl alcohol, and 0.3 g of a commercially available dye (Hoster Palm Pink E) was dissolved in the obtained solution. After stirring the mixture for 30 minutes,
The mixture was filtered with a polypropylene filter having a pore size of 1 μm. Example 1 except that the obtained coating solution for a filter layer was used.
An optical filter was produced in the same manner as described above.

(Measurement of Absorbance) The transmission spectrum of the prepared optical filter was measured using a spectrophotometer (U-3210, manufactured by Hitachi, Ltd.). Reference was made with air. From the spectrum, the absorption maximum (λmax) and the half width were determined. The results are shown in Table 1.
In addition, the transmittance | permeability in the absorption maximum of all the optical filters was in the range of 25-35%.

(Light fastness test) The prepared optical filter was irradiated with light from the side opposite to the filter layer by a xenon lamp so that the illuminance was 150,000 lux.
The residual amount of the dye after irradiation for 0 hours was measured. The residual amount was calculated according to the following equation. Residual amount = 100 × (100−transmittance after irradiation) / (10
0—Transmittance Before Irradiation) The transmittance is a value measured at the absorption maximum wavelength of the dye. The results are shown in Table 1.

[0053]

[Table 1] Table 1 ──────────────────────────────────── Optical filter Dye adsorption λmax Half width Light fastness ──────────────────────────────────── Example 1 (1) Yes 598 nm 35 nm 83% Example 2 (2) Yes 591 nm 40 nm 83% Example 3 (3) Yes 588 nm 42 nm 86% Comparative Example 1 (a) No 572 nm 70 nm 0% Comparative Example 2 Hoster pump E No 570 nm 150 nm 100% ──────────────────────────────

When the optical filters of Examples 1 to 3 were attached to the surface of the plasma display panel, an image having good contrast was obtained, and improvement in white light and red light was recognized.

Example 4 (Formation of Undercoat Layer) On one side of a transparent triacetyl cellulose film having a thickness of 80 μm, gelatin dispersed in methanol and acetone was applied so as to have a thickness of 200 nm, and dried. Was formed.

(Formation of Hard Coat Layer) 25 parts by weight of dipentaerythritol hexaacrylate (DPHA,
Nippon Kayaku Co., Ltd.), 25 parts by weight of a urethane acrylate oligomer (UV-6300B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 2 parts by weight of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) and 0 5 parts by weight of a sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.)
It was dissolved in 0 parts by weight of methyl ethyl ketone. The obtained coating solution was applied to the surface opposite to the undercoat layer of the transparent support using a bar coater, dried, and then irradiated with ultraviolet rays to form a hard coat layer (layer thickness: 6 μm).

(Formation of Low Refractive Index Layer) A low refractive index layer was formed on the hard coat layer in the same manner as in Example 1 using a coating liquid for a low refractive index layer.

(Formation of Filter Layer) The coating solution for the filter layer used in Example 1 was applied onto the undercoat layer so that the coating amount of the dye was 30 mg / m ² ,
After drying for 0 minutes, a filter layer was formed. For the manufactured optical filter, the absorption maximum, the transmittance at the absorption maximum, and the half width were measured, and the same result as that of the optical filter manufactured in Example 1 was obtained.

Example 5 (Formation of Undercoat Layer) As in Example 1, an undercoat layer (a) and a second undercoat layer (a) were formed on one surface of the transparent support. A latex comprising vinylidene chloride-acrylic acid-methyl acrylate copolymer was applied to a thickness of 120 nm on the side of the transparent support on which the undercoat layer was not provided, to form an undercoat layer (b).

(Formation of Second Undercoat Layer) On the undercoat layer (b), an acrylic latex (HA16, manufactured by Nippon Acrylic Co., Ltd.) was applied to a thickness of 50 nm to form a second undercoat layer (b). Was formed.

(Formation of Filter Layer) The coating solution for the filter layer used in Example 1 was applied onto the second undercoat layer (b).
Apply so that the coating amount of the dye is 30 mg / m ² ,
After drying at 20 ° C. for 10 minutes, a filter layer was formed.

(Formation of Hard Coat Layer) A hard coat layer was formed on the filter layer in the same manner as in Example 4.

(Formation of Low Refractive Index Layer) A low refractive index layer was formed on the hard coat layer by using a coating liquid for a low refractive index layer in the same manner as in Example 1, to produce an optical filter. For the manufactured optical filter, the absorption maximum, the transmittance at the absorption maximum, and the half width were measured, and the same result as that of the optical filter manufactured in Example 1 was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a layer configuration of an antireflection film in which a filter layer is provided on a side opposite to a transparent support from an antireflection layer.

FIG. 2 is a schematic cross-sectional view showing a layer configuration of an antireflection film in which a filter layer and an antireflection layer are provided on the same side of a transparent support. DESCRIPTION OF SYMBOLS 1 Transparent support 2 Filter layer 3 Low refractive index layer 4 Hard coat layer 5 High refractive index layer 6 Medium refractive index layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 1/11 G02B 1/10 A F-term (Reference) 2H048 CA04 CA14 CA19 CA24 CA26 2K009 AA02 AA15 BB24 CC24 CC26 DD02 DD17 4J002 AB011 AB051 AC081 AD011 BC031 BD041 BE021 BE061 BG061 BJ001 CG001 DD077 DE147 DJ007 DJ017 DJ047 FB087 FD017 FD096 GP00 4J038 BA021 BA171 BA181 CC031 CC041 CD031 CE021 CE071 HA031 HA031KA031

Claims (12)

[Claims] 1. An optical filter having a filter layer containing a dye and a polymer binder on a transparent support, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. An optical filter, which is characterized in that: 2. The optical filter according to claim 1, which is used for a plasma display panel. 3. The fine particles having an average particle size of 0.005 to 2
The optical filter according to claim 1, wherein the optical filter is 0 μm inorganic fine particles. 4. The dye adsorbed on the surface of the fine particles is 5
The optical filter according to claim 1, which has an absorption maximum in a wavelength region of 60 to 620 nm. 5. An antireflection film comprising: a filter layer containing a dye and a polymer binder; a transparent support; and a low refractive index layer having a refractive index lower than that of the transparent support. An antireflection film, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. 6. The antireflection film according to claim 5, which is used for a plasma display panel. 7. The fine particles having an average particle diameter of 0.005 to 2
The antireflection film according to claim 5, wherein the antireflection film is inorganic fine particles of 0 µm. 8. The dye adsorbed on the surface of the fine particles is 5
The antireflection film according to claim 5, which has an absorption maximum in a wavelength region of 60 to 620 nm. 9. An antireflection film comprising a transparent support, a filter layer containing a dye and a polymer binder, and a low refractive index layer having a refractive index lower than that of the transparent support, which are laminated in this order. An antireflection film, wherein the filter layer further contains fine particles, and the dye is contained in the filter layer in a state where the dye is adsorbed on the surface of the fine particles. 10. The antireflection film according to claim 9, which is for a plasma display panel. 11. The antireflection film according to claim 9, wherein the fine particles are inorganic fine particles having an average particle size of 0.005 to 20 μm. 12. The dye adsorbed on the surface of the fine particles,
The antireflection film according to claim 9, which has an absorption maximum in a wavelength range of 560 to 620 nm.