JP2000241602A - Antireflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film having an appropriate color correcting function in addition to an antireflection function. SOLUTION: This antireflection film comprises a filter layer 3 containing a dye and a polymer binder, a transparent backing 1, and a low refractive index layer 6 having a lower refractive index than the transparent backing 1, which are laminated in this order. In this case, there is formed an undercoat layer 2 containing a polymer of glass transition temperature from 60 deg.C to -20 deg.C, or the undercoat layer 2 having a rough surface on its filter layer side, between the filter layer 3 and the transparent backing 1, while there are formed undercoat layers 4, 5 consisting of 2 layers containing a polymer of glass transition temperature from 60 deg.C and to -20 deg.C, between the low refractive index layer 6 and the transparent backing 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antireflection film having a transparent support, a low refractive index layer and a filter layer. In particular, the present invention relates to a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), a cathode ray tube display (CR)
T) relates to an antireflection film attached to the surface of an image display device such as a fluorescent display tube or a field emission display for antireflection and 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),
An image display device such as a fluorescent display tube or a field emission display has a problem that the contrast is reduced due to the background being reflected on the display. As means for solving 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 formed by a vacuum deposition method, a sputtering method, an ion plating method, a CVD method, or a PVD method. The coating layer is generally formed by applying fine particles and a binder. The coating layer is described in JP-A-59-49501.
And JP-A-59-50401, JP-A-60-59250, and JP-A-7-48527.

[0003] In addition to anti-reflection, the image display device also requires color correction. In image display devices, in principle,
A color image is displayed using a combination of the three primary colors of red, blue and green. 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 light emitted from the three primary color phosphors contains extra light (wavelengths in the range of 500 to 550 nm and 560 to 620 nm). Therefore, it has been proposed to perform color correction using a filter that absorbs light of a specific wavelength in order to correct the color balance of display colors. Japanese Patent Application Laid-Open No. 58-1539 discloses color correction using a filter.
04, 61-188501, JP-A-3-2319
No. 88, No. 5-205564, No. 9-145918
Nos. 9-306366 and 10-26704. It is also conceivable to incorporate a filter function into the antireflection film. JP-A-61-1
88501, JP-A-5-205643, 9-14
No. 5918, No. 9-306366, No. 10-2670
No. 4 discloses an antireflection film having a built-in filter function. JP-A-61-188501, JP-A-5-205643, JP-A-9-145918, and JP-A-9-145918
In the antireflection film described in each of JP-A-306366, a dye or a pigment is added to a transparent support of the antireflection film, and the support functions as a filter. JP-A-10-
In the antireflection film described in 26704, the hard coat layer (surface hardened layer) provided between the transparent support and the antireflection layer is colored, and the hard coat layer functions as a filter.

[0004]

If the transparent support or the hard coat layer of the antireflection film is colored, the transparent support or the hard coat layer functions as a filter. However, the types of dyes and pigments 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). Dyes and pigments to be added to the transparent support are required to have extremely 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 and pigments that fade. Dyes or pigments used for color correction are required to have various absorption spectrum characteristics depending on the type of image display device. If the types of dyes and pigments used for color correction are limited, it is difficult to perform appropriate correction.

The present inventor has proposed that a dye be added 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, so that the polymer layer functions as a filter layer. It was investigated. Due to the optical properties of the anti-reflective coating, the filter layer must be provided adjacent to the transparent support. However, the affinity between the dye-containing polymer layer and the transparent support (plastic or glass) is low, and the dye-containing polymer layer is easily separated from the transparent support. It is considered that the reason why the conventional technique allows the transparent support or the hard coat layer to function as a filter is that a problem occurs in adhesion between the filter layer and the transparent support. Further, since the affinity between the low refractive index layer and the filter layer is low, the low refractive index layer needs to be provided on the surface of the transparent support opposite to the filter layer and adjacent to the transparent support. However, the low-refractive-index layer also generally has low affinity with the transparent support (plastic or glass),
The low refractive index layer is easily peeled from the transparent support. Therefore, it is necessary to provide an adhesive layer between the low refractive index layer and the transparent support. In this case, in order to sufficiently lower the reflectance of the antireflection film, it is necessary to appropriately design the refractive index and the thickness of the low refractive index layer and the undercoat layer that makes the low refractive index layer adhere to the transparent support. An object of the present invention is to provide an antireflection film having an appropriate color correction function in addition to an antireflection function.

[0006]

The object of the present invention has been attained by the following antireflection film. 1) having a filter layer containing a dye and a polymer binder on one side of the transparent support, and having a low refractive index layer having a refractive index lower than that of the transparent support on the other side of the transparent support; In the antireflection film, the glass transition temperature between the filter layer and the transparent support is 60 ° C. or lower.
An undercoat layer containing a polymer of 0 ° C. or more or an undercoat layer having a rough surface on the filter layer side is provided, and a glass transition temperature between 60 ° C. and −20 ° C. between the low refractive index layer and the transparent support. An antireflection film comprising a two-layer undercoat layer containing the above polymer. 2) Among the two undercoat layers provided between the low refractive index layer and the transparent support, the first undercoat layer in contact with the transparent support has a thickness of t1, a refractive index of n1, and a contact with the low refractive index layer. Item 2. The antireflection film according to item 1, wherein the following general formulas (1) and (2) are satisfied at the same time, where t2 is the thickness of the second undercoat layer and n2 is the refractive index. (1) 140 nm ≦ t1 + t2 ≦ 200 nm (2) 1.50 ≦ n1 ≦ 1.60, 1.45 ≦ n2 ≦
1.55 3) The antireflection film according to item 2, wherein the first undercoat layer is made of a styrene-butadiene copolymer, and the second undercoat layer is made of an acrylic resin layer. 4) Of the two undercoat layers provided between the low refractive index layer and the transparent support, the thickness of the first undercoat layer in contact with the transparent support is set to t.
1. When the refractive index is n1, the thickness of the second undercoat layer in contact with the low refractive index layer is t2, and the refractive index is n2, the following general formulas (1) and (3) are satisfied at the same time. Item 2. The antireflection film according to Item 1. (1) 140 nm ≦ t1 + t2 ≦ 200 nm (3) 1.45 ≦ n1 ≦ 1.55, 1.50 ≦ n2 ≦
1.605 5) The antireflection film according to item 4, wherein the first undercoat layer is made of a styrene-butadiene copolymer, and the second undercoat layer is made of an acrylic resin layer. 6) The filter layer has an absorption maximum having a transmittance of 50 to 85% in a wavelength range of 500 to 550 nm and a wavelength of 5 to 85%.
Item 6. The antireflection film according to any one of Items 1 to 5, having an absorption maximum having a transmittance of 5 to 60% in a range of 60 to 620 nm. 7) The antireflection film for an image display device according to any one of Items 1 to 6, which is used for color balance correction of the image display device. 8) An anti-reflection film for a plasma display panel, wherein the image display device according to item 7 is a plasma display panel (PDP). 9) A front plate for a plasma display panel, comprising an antireflection film having the filter layer according to any one of claims 1 to 6. 10) The filter layer side of the antireflection film having the filter layer is disposed on the inner surface of the front plate, and the low refractive index layer side is disposed so as to face the image display surface of the plasma display panel. Item 10. A front plate for a plasma display panel according to item 9. 11) forming an antireflection film having the filter layer according to any one of items 1 to 6 on the surface of a plasma display panel;
A plasma display device provided on at least one of an outer surface of a plasma display panel front plate and an inner surface of the front plate.

[0007]

According to the present invention, the present invention provides an undercoat layer between the transparent support and the filter layer and a two-layer undercoat layer between the transparent support and the low-refractive-index layer. It was studied to enhance the adhesive strength between the filter layer and the low refractive index layer. However, the provision of the undercoat layer must not impair the optical function of the antireflection layer. As a result, the present inventor uses an undercoat layer containing a polymer having a glass transition temperature of 60 ° C. or lower and −20 ° C. or higher or an undercoat layer having a rough surface on the filter side on the transparent support surface on which the filter layer is coated, and has a low refractive index. Antireflection by controlling the refractive index of each undercoat layer and the thickness of the undercoat layer comprising two layers containing a polymer having a glass transition temperature of 60 ° C or lower and -20 ° C or higher on the transparent support surface on which the refractive index layer is coated. Without affecting the optical function of the film, the adhesion between the transparent support, the filter layer and the low refractive index layer was successfully enhanced.

As a result of eliminating the problem of the adhesive strength between the transparent support and the filter layer, various kinds of dyes can be used for the filter layer. For example, in the field of silver halide photography, various photographic dyes have been developed. The absorption spectral properties of photographic dyes have also been studied in detail. It has been difficult to add a photographic dye to a transparent support or a hard coat layer by a conventional method. According to the present invention, various photographic dyes can be used for the antireflection film. In addition, by adjusting the thickness and the refractive index of the two undercoat layers between the transparent support and the low refractive index layer, the reflectance on the low refractive index layer side is kept small while the low refractive index layer and the transparent support layer are kept low. The body's adhesive strength has been strengthened, and the durability has reached practical use.
As a result, in the antireflection film of the present invention, in addition to the antireflection function, it is possible to obtain an appropriate color correction function according to the type of the image display device.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical layer structure of an antireflection film is as follows.
This will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing one layer configuration of the antireflection film of the present invention. The embodiment shown in FIG. 1 includes a filter layer (3), an undercoat layer (2) of a filter layer, a transparent support (1), a first undercoat layer (4) of a low refractive index layer, and a second undercoat layer of a low refractive index layer. It has a layer structure in the order of a layer undercoat layer (5) and a low refractive index layer (6). The thickness of the first undercoat layer (4) of the low refractive index layer is t1, the refractive index is n1, the thickness of the second undercoat layer (5) of the low refractive index layer is t2, and the refractive index is n2. At this time, the thicknesses of the layer (4) and the layer (5) are
(1) It is necessary to satisfy the relationship of 140 nm ≦ t1 + t2 ≦ 200 nm. Further, the refractive indices of the layer (4) and the layer (5) must satisfy one of the following two relationships (a) and (b). (A): The refractive index of the low refractive index layer <the refractive index of the transparent support, and (2) 1.50 ≦ n1 ≦ 1.60, 1.45 ≦
n2 ≦ 1.55 (b): The refractive index of the low refractive index layer <the refractive index of the transparent support, and (3) 1.50 ≦ n2 ≦ 1.60, 1.45 ≦
n1 ≦ 1.55 In particular, the relationship between the refractive index of the transparent support and the low refractive index layer is such that the refractive index of the low refractive index layer <the refractive index of the second undercoat layer of the low refractive index layer <the refractive index of the low refractive index layer. Refractive index of first undercoat layer <Refractive index of transparent support or refractive index of low refractive index layer <Refractive index of first undercoat layer of low refractive index layer <Refractive index of second undercoat layer of low refractive index layer < The case of the refractive index of the transparent support is preferred.

(Transparent support) Examples of the material 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 absorber added is preferably 0.01 to 20% by weight of the transparent support, 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 the inorganic _{compound, SiO 2, TiO 2, BaSO} 4, CaCO 3, talc and kaolin. The transparent support is preferably subjected to a surface treatment in order to further enhance the adhesiveness with the undercoat layer. Examples of surface treatments 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 corona discharge treatment is more preferred. (Undercoat layer) In the present invention, an undercoat layer containing a polymer having a glass transition temperature of 60 ° C or lower and -20 ° C or higher or an undercoat layer having a rough surface on the filter layer side is provided between the transparent support and the filter layer. Provide. Furthermore, in the present invention, the glass transition temperature between the support and the low refractive index layer is 60 ° C. or less.
Two undercoat layers including a polymer layer at 20 ° C. or higher are provided.
This improves the adhesive strength between the transparent support and the filter layer and between the transparent support and the low refractive index layer. In this case, the thickness and the refractive index of the two-layer undercoat layer between the low refractive index layer and the transparent support are determined by the following formulas (1) and (2) or (1) so as not to impair the function as the antireflection layer. ) And (3) must be provided with values of the film thickness and the refractive index that satisfy both the expressions. (1) 140 nm ≦ t1 + t2 ≦ 200 nm (2) 1.50 ≦ n1 ≦ 1.60, 1.45 ≦ n2 ≦
1.55 (3) 1.50 ≦ n2 ≦ 1.60, 1.45 ≦ n1 ≦
1.55 Here, t1: the thickness of the first undercoat layer in contact with the transparent support, t2: the thickness of the second undercoat layer, n1: the refractive index of the first undercoat layer in contact with the transparent support, n2:
This is the refractive index of the second undercoat layer. The thickness of the undercoat layer between the transparent support and the filter layer is
It is preferably from 20 nm to 1 μm, more preferably from 50 to 700 nm. The undercoat layer may be composed of two or more different layers. Glass transition temperature of 60 ° C or less -20
The undercoat layer containing the polymer at a temperature of not less than ° C. adheres the transparent support and the filter layer due to the tackiness of the polymer. Polymers having a glass transition temperature of 60 ° C or lower and -20 ° C or higher are obtained by polymerization or copolymerization of vinyl chloride, vinylidene chloride, vinyl acetate, butadiene, neoprene, styrene, chloroprene, acrylate, methacrylate, acrylonitrile or methyl vinyl ether. Obtainable. The glass transition temperature is desirably 60C or lower and -20C or higher, more desirably 55C or lower and -15C or higher, and most desirably 50C or lower and -10C or higher. 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. Using a polymer latex having a glass transition temperature of 60 ° C. or lower and −20 ° C. or higher, a glass transition temperature of 60 ° C.
An undercoat layer containing a polymer at a temperature of -20 ° C or lower and a filter layer side having a rough surface may be formed. The average particle size of the latex used for the undercoat layer between the filter layer and the transparent support and between the low refractive index layer and the transparent support is 0.0
It is preferably 2 to 3 μm, and 0.05 to 1 μm.
m is more preferable. The undercoat layer consisting of two layers between the low refractive index layer and the transparent support has a first layer of styrene-
A configuration made of a butadiene copolymer and the second layer made of an acrylic resin layer can be preferably used. The embodiment described in JP-A-10-166517 can be preferably used for such an undercoat layer. In the undercoat layer, a solvent that swells the transparent support, a matting agent,
Surfactants, antistatic agents, coating aids and hardeners may be added.

(Second Undercoat Layer of Filter Layer) A second undercoat layer may be provided between the undercoat layer and the filter layer. As the second undercoat layer, a polymer having a high affinity for the binder polymer of the filter layer (for example, acrylic resin,
It is preferably formed using a cellulose derivative, gelatin, casein, starch, polyvinyl alcohol, soluble nylon, or polymer latex. A solvent for swelling the transparent support, a matting agent, a surfactant, an antistatic agent, a coating aid, a hardening agent, and the like can be added to the second undercoat layer.

(Low Refractive Index Layer) As 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 refractive index of the low refractive index layer is
1.20 to 1.55, preferably 1.30
It is more preferably from 1.55 to 1.55. The thickness of the low refractive index layer is preferably 50 to 400 nm,
More preferably, it is 50 to 200 nm. The low refractive index layer is a layer made of a fluoropolymer having a low refractive index (JP-A-57-34526, JP-A-3-130103).
, JP-A-6-115023, JP-A-8-313702, and JP-A-7-168004), and a layer obtained by a sol-gel method (JP-A-5-208811, JP-A-6-299).
Nos. 091 and 7-168003) or a layer containing fine particles (JP-B-60-59250, JP-A-5-13021, JP-A-6-56478 and JP-A-7-923).
No. 06 and No. 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 fine particles preferably has a porosity of 3 to 50% by volume, and 5 to 3% by volume.
More preferably, it has a porosity of 5% by volume.

The anti-reflection layer can provide a 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%.

(Filter layer) The thickness of the filter layer is 1
It is preferably from 15 to 15 μm. The filter layer is
A wavelength range of 500 to 550 nm (green) and a wavelength of 56
It has an absorption maximum both in the range of 0 to 620 nm (between green and red). The transmittance at the absorption maximum in the wavelength range of 500 to 550 nm is preferably in the range of 50 to 85%. The absorption maximum in the wavelength range of 500 to 550 nm is set to adjust the emission intensity of the green phosphor having high visibility. It is preferable that the emission region of the green phosphor be cut smoothly. The half width at the absorption maximum in the wavelength range of 500 to 550 nm (the width of the wavelength region showing half the absorbance of the absorbance at the absorption maximum) is 30 to 300 nm.
Is preferably 40 to 300 nm, more preferably 50 to 150 nm, and most preferably 60 to 150 nm.

The transmittance at the absorption maximum in the wavelength range of 560 to 620 nm is preferably in the range of 5 to 60%. The absorption maximum in the wavelength range of 560 to 620 nm is set to selectively cut a sub-band that reduces the color purity of the red phosphor. In the PDP, unnecessary light emission near 595 nm emitted by excitation of neon gas is also cut. By separating the absorption maximum according to the present invention, light can be selectively cut without adversely affecting the color tone of the green phosphor. In order to further reduce the effect on the color tone of the green phosphor, it is preferable to sharpen the peak of the absorption spectrum. Specifically, the half width at the absorption maximum in the wavelength range of 560 to 620 nm is preferably 15 to 200 nm, more preferably 20 to 100 nm, and more preferably 22 to 80 nm.
Most preferably, it is nm.

Dye (dye or pigment, preferably dye)
Is used to impart the above absorption spectrum to the filter layer. As the dye having an absorption maximum in the wavelength range of 500 to 550 nm, squarylium-based, azomethine-based,
Cyanine, oxonol, anthraquinone, azo or benzylidene compounds are preferably used. As azo dyes, GB 593,703 and 575
No. 691, U.S. Pat. No. 2,956,879, and Hiroshi Horiguchi, "Review Synthetic Dyes", and many azo dyes described in Sankyo Publishing Co., Ltd. can be used. An azo dye represented by the general formula (a6) is preferred. Examples of the dye having an absorption maximum in the wavelength range of 500 to 550 nm are shown below.

[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a monovalent group, M represents a metal atom, and m ¹ , m ² and m ³ each independently represent 1 to
Represents an integer of 4. As a metal atom represented by M,
Transition metals are preferred, Fe, Co, Ni, Cu, Zn,
Cd and the like can be mentioned, and Cu is particularly preferred. As the dye having an absorption maximum in the wavelength range of 560 to 620 nm, cyanine, squarylium, azomethine, xanthene, oxonol or azo compounds are preferably used. 560 to 620 nm wavelength
Examples of dyes having an absorption maximum in the range of are shown below.

[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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A dye having an absorption maximum in both the wavelength range of 500 to 550 nm and the wavelength range of 560 to 620 nm can be used for the filter layer. For example, when the dye is in an aggregated state such as a fine particle dispersion, the wavelength generally shifts to the longer wavelength side, and the peak becomes sharp. For this reason, some dyes having an absorption maximum in the wavelength range of 500 to 550 nm have an aggregate having an absorption maximum in the range of 560 to 620 nm. When such a dye is used in a state of forming an aggregate partially, the wavelength is in the range of 500 to 550 nm and the wavelength is 560.
It is possible to obtain an absorption maximum in both the range from 620 nm to 620 nm. Examples of such dyes are shown below.

[0030]

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[0031]

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[0032]

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In the filter layer, two or more kinds of dyes as described above can be used in combination. The filter layer further includes a polymer binder. Natural polymers (eg, gelatin, cellulose derivatives, alginic acid) or synthetic polymers (eg, polymethyl methacrylate, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl chloride, styrene-butadiene copolymer, polystyrene, polycarbonate, water-soluble polyamide) It can be used as a polymer binder. Particularly preferred are hydrophilic polymers (the above-mentioned natural polymers, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl alcohol, and water-soluble polyamide).

(Other Layers) The antireflection film may be provided with a hard coat layer, a lubricating layer, an antistatic 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 lubrication layer may be formed on the outermost surface of the antireflection film. 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 lubricating layer is preferably 2 to 20 nm.

The antireflection layer (low refractive index layer), filter layer, undercoat layer, hard coat layer, lubricating layer and other layers can be formed by a general coating method. 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 (US Pat. No. 26812).
No. 94). Two or more layers may be formed by simultaneous coating. The simultaneous coating method is described in U.S. Pat. Nos. 2,761,791 and 2,918,898 and 3,508.
No. 947, No. 3526528, and in Yuji Harazaki, “Coating Engineering”, p. 253 (published by Asakura Shoten in 1973).

(Use of antireflection film) The antireflection film is used for a liquid crystal display (LCD), a plasma display panel (P).
DP), electroluminescent display (EL)
D) or an image display device such as a cathode ray tube display device (CRT). When the antireflection film of the present invention is used as an internal 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, a phosphor, and a front plate that protects a main body. 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. The front plate is located on the front surface of the main body so as to protect these plasma display main bodies. The front plate is made of a tempered glass or plastic plate (such as acrylic) having sufficient strength to protect the main body. In the antireflection film of the present invention, an antireflection low refractive index layer is disposed on the back side of the inner surface plate so as to face the image display surface. Plasma display panels (PDPs) are already commercially available. The plasma display panel is described in JP-A-5-205643 and JP-A-9-306366.

[0037]

EXAMPLES Example 1 (Formation of Undercoat Layer) After a corona treatment was applied to both sides of a transparent polyethylene terephthalate film having a thickness of 100 μm,
A latex made of a styrene-butadiene copolymer having a refractive index of 1.55 and a glass transition temperature of 37 ° C. (manufactured by Zeon Corporation, LX407C5) was applied to both surfaces to form an undercoat layer. The film was dried so as to have a thickness of 300 nm on the surface on which the filter layer was to be provided and to have a thickness of 150 nm on the surface on which the low refractive index layer was to be provided.

(Formation of Second Undercoat Layer) An aqueous solution of gelatin containing acetic acid and glutaraldehyde is applied to a thickness of 100 nm after drying on the undercoat layer on the surface on which the filter layer is to be provided. Acrylic latex (HA16, manufactured by Nippon Acrylic Co., Ltd.) having a refractive index of 1.50 and a glass transition temperature of 50 ° C. is applied on the undercoat layer on the surface on which the is to be provided so as to have a thickness of 20 nm after drying. Two undercoat layers were formed.

(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 1 μm polypropylene filter. The obtained low-refractive-index layer coating solution is applied on one surface of a transparent support (a surface having a styrene-butadiene copolymer latex of 150 nm and an acrylic latex of 20 nm as an undercoat layer) using a bar coater to a dry film thickness of 96 nm. And apply
The coating was dried and cured at 120 ° C. for 15 minutes to form a low refractive index layer.

(Formation of Filter Layer) In 180 g of a 10% by weight aqueous solution of gelatin, 0.05 g of the dye (c1) and 0.15 g of the dye (a6-1) were dissolved and stirred at 40 ° C. for 30 minutes. The mixture was filtered with a polypropylene filter. The obtained coating solution for a filter layer was applied onto the second undercoat layer on the opposite side of the transparent support on which the low refractive index layer was applied, so that the dry film thickness became 3.5 μm.
After drying for a minute, a filter layer was formed, and an antireflection film was produced.

When the spectral transmittance of the antireflection film was examined,
It has absorption maximums at 535 nm and 595 nm, and the transmittance at the absorption maximum is 69% at 535 nm, and 595 n
m was 23%. The half width of the absorption maximum is
The absorption maximum at 535 nm was 63 nm, and the absorption maximum at 595 nm was 30 nm.

Example 2 (Formation of Undercoat Layer) After a corona treatment was applied to both sides of a transparent polyethylene terephthalate film having a thickness of 100 μm,
A latex made of a styrene-butadiene copolymer having a refractive index of 1.55 and a glass transition temperature of 37 ° C (LX407C5, manufactured by Zeon Corporation) is provided on the surface on which the filter layer is provided.
Is applied so as to have a thickness of 300 nm, and the opposite surface on which the low refractive index layer is provided has a refractive index of 1.58 and a glass transition temperature −
A latex made of vinylidene chloride-acrylic acid-methyl acrylate copolymer at 10 ° C. was applied to a thickness of 145 nm.

(Formation of Second Undercoat Layer) A second undercoat layer was formed in the same manner as in Example 1.

(Formation of Low Refractive Index Layer) A low refractive index layer was formed in the same manner as in Example 1.

(Formation of Filter Layer) Dye (a6-1)
A filter layer was formed in the same manner as in Example 1 except that 0.15 g of the dye (a5) was used instead, and an antireflection film was produced.

When the spectral transmittance of the antireflection film was examined,
It has absorption maximums at 534 nm and 594 nm, and the transmittance at the absorption maximum is such that the absorption maximum at 534 nm is 65%, 594 n
m was 21%. The half width of the absorption maximum is
The absorption maximum at 534 nm was 78 nm, and the absorption maximum at 594 nm was 28 nm.

Example 3 (Formation of undercoat layer) An undercoat layer was formed in the same manner as in Example 1.

(Formation of Second Undercoat Layer) A second undercoat layer was formed in the same manner as in Example 1.

(Formation of Low Refractive Index Layer) A low refractive index layer was formed in the same manner as in Example 1.

(Formation of Filter Layer) Dye (a6-1)
Instead, a filter layer was formed in the same manner as in Example 1 except that 0.05 g of the dye (a1) was used, to produce an optical filter.

When the spectral transmittance of the antireflection film was examined,
It has absorption maximums at 533 nm and 594 nm, and the transmittance at the absorption maximum is 63% at 533 nm and 594 n.
m was 22%. The half width of the absorption maximum is
The absorption maximum at 533 nm was 63 nm, and the absorption maximum at 594 nm was 29 nm.

Comparative Examples 1 to 11 Comparative Examples 1 to 8: Optical filters were produced in the same manner as in Example 1 except that the thickness of the undercoat layer of the low refractive index layer was changed. Table 1 shows the thickness of the undercoat layer of the low refractive index layer. Comparative Examples 9 to 11: Optical filters were produced in the same manner as in Example 1 except that the amount of the dye was changed. Table 2 shows the amount of the dye added.

[0053]

[Table 1]

[0054]

[Table 2]

(Evaluation of Optical Properties of Antireflection Layer)
The peak absorption wavelength, half width, and average reflectance in the wavelength region of 500 to 600 nm of the antireflection films prepared in Comparative Example 3 and Comparative Examples 1 to 11 were measured. The results are shown in Table 3.

(Evaluation of Adhesion of Antireflection Film Constituent Layer) An acrylic pressure-sensitive adhesive having a thickness of 30 μm was applied to the filter layer surface of the antireflection films prepared in Examples 1 to 3 and Comparative Examples 1 to 7. Then, the surface was attached to glass, and the antireflection layer side was subjected to a tape peeling test by a cross cut method. A sample adhered to glass was irradiated with visible light of 150,000 lux from the antireflection layer side by a xenon lamp for 100 hours, and then a similar tape peeling test was performed. Peeled area is 7
C was evaluated for 0% or more, B for 30 to 70%, and A for less than 30%. The results are shown in Table 3.

[0057]

[Table 3]

(Evaluation of Filter Function) Plasma Display Panel (PDS4202J-H, Fujitsu Limited)
Examples 1 to 3 and Comparative Examples 1 to 11
An acrylic pressure-sensitive adhesive was applied to a thickness of 30 μm on the filter layer surface of the antireflection film prepared in the above, and the surface was adhered to the inner surface. Thereafter, the front plate was attached to the plasma display panel body as before. The displayed image was measured for contrast, visually evaluated for white light and red light, and evaluated for sharpness of the outline of the image. The results are shown in Table 4.

[0059]

[Table 4]

Comprehensive Evaluation Results From Tables 3 and 4, those using the antireflection films prepared in Examples 1 to 3 were excellent in adhesion, contrast, color reproducibility of images and sharpness of contour. Comparative Examples 1 to 5 were good in contrast and color reproducibility of the image, but poor in adhesion, and in Comparative Examples 5 and 5, the average reflectance was high, so that the outline of the image was poor. In Comparative Examples 6 to 8, the contrast, the color reproducibility of the image, and the adhesion were good, but the sharpness of the outline of the image was poor due to the high average reflectance. Comparative Example 9
No. 11 had good adhesion and sharpness of the outline of the image,
Poor contrast and color reproducibility of image.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a layer configuration of an antireflection film. DESCRIPTION OF SYMBOLS 1 Transparent support 2 Undercoat layer of filter layer 3 Filter layer 4 First undercoat layer of low refractive index layer 5 Second undercoat layer of low refractive index layer 6 Low refractive index layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H01J 29/89 H01J 29/89

Claims (11)

[Claims] 1. A low refractive index having a filter layer containing a dye and a polymer binder on one side of a transparent support and having a refractive index lower than that of the transparent support on the other side of the transparent support. In the antireflection film having a layer, the glass transition temperature between the filter layer and the transparent support is 60.
An undercoat layer containing a polymer having a temperature of -20 ° C or lower or an undercoat layer having a rough surface on the filter layer side is provided,
An antireflection film comprising a low-refractive-index layer and a transparent support, and an undercoat layer comprising two layers containing a polymer having a glass transition temperature of 60 ° C or lower and -20 ° C or higher. 2. Among two undercoat layers provided between the low refractive index layer and the transparent support, the first undercoat layer in contact with the transparent support has a thickness of t1, a refractive index of n1, and a low refractive index. When the thickness of the second undercoat layer in contact with the layer is t2 and the refractive index is n2,
The anti-reflection film according to claim 1, wherein the following general formulas (1) and (2) are simultaneously satisfied. (1) 140 nm ≦ t1 + t2 ≦ 200 nm (2) 1.50 ≦ n1 ≦ 1.60, 1.45 ≦ n2 ≦
1.55 3. The antireflection film according to claim 2, wherein the first undercoat layer is made of a styrene-butadiene copolymer, and the second undercoat layer is made of an acrylic resin layer. 4. The two undercoat layers provided between the low refractive index layer and the transparent support, wherein the first undercoat layer in contact with the transparent support has a thickness of t1, a refractive index of n1, and a low refractive index layer. The second in contact with
The anti-reflection film according to claim 1, wherein the following general formulas (1) and (3) are satisfied at the same time when the thickness of the undercoat layer is t2 and the refractive index is n2. (1) 140 nm ≦ t1 + t2 ≦ 200 nm (3) 1.45 ≦ n1 ≦ 1.55, 1.50 ≦ n2 ≦
1.60 5. The antireflection film according to claim 4, wherein said first undercoat layer is made of a styrene-butadiene copolymer, and said second undercoat layer is made of an acrylic resin layer. 6. The filter layer having a wavelength of 500 to 5
6. An absorption maximum having a transmittance of 50 to 85% in a range of 50 nm and an absorption maximum of 5 to 60% in a range of 560 to 620 nm. The antireflection film as described in the above. 7. The antireflection film for an image display device according to claim 1, wherein the antireflection film is used for color balance correction of the image display device. 8. An antireflection film for a plasma display panel, wherein the image display device according to claim 7 is a plasma display panel (PDP). 9. A front panel for a plasma display panel, comprising an antireflection film having the filter layer according to claim 1. Description: 10. The filter layer side of the antireflection film having the filter layer is disposed on the inner surface of the front plate, and the low refractive index layer side is disposed so as to face the image display surface of the plasma display panel. Claim 9
2. A front plate for a plasma display panel according to claim 1. 11. An anti-reflection film having the filter layer according to claim 1, wherein the anti-reflection film has at least one of a surface of a plasma display panel, an outer surface of a front panel of the plasma display panel, and an inner surface of the front panel. A plasma display device, comprising: