JP2001272532A - Optical filter, front plate using the same and picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunctional optical filter which is excellently suited for manufacturing, is not bulky, is light in weight, is achromatic in itself and has an excellent color correction function and a front plate and a picture display device using the same. SOLUTION: The optical filter, together with the front plate and the picture display device using the same, is characterized by having a visible light filter layer on at least one side of a transparent supporting body and by exhibiting a color, under irradiation with standard D65 light, within a range expressed by the following inequalities (I) when the optical filter with the visible light filter is placed on the front side of the picture display device and the colorimetry of the front surface of the picture display device provided with the optical filter is conducted according to the method of measurement for a reflection object described in JIS Z 8722. 0<=|a*|<=10, 0<=|b*|<=10 (I). Here a*, b* express a*, b* values in CIE 1976 L*a*b color space expressed corresponding to JIS Z 8729.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a visible filter layer (hereinafter, also simply referred to as "filter layer") for absorbing visible light, a transparent support, and a low refractive index layer. The present invention relates to an achromatic optical filter. More specifically, the present invention relates to an image display device such as 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 field emission display. The present invention relates to an optical filter which is preferably used for the display of a color filter and is attached for antireflection and improvement of color reproducibility, and has an achromatic color of the filter itself. More specifically, the present invention provides a plasma display panel (PDP) having an optical filter with improved anti-reflection and color reproducibility, and an achromatic color of the filter itself.
The present invention relates to an image display device such as a front panel and a PDP body.

[0002]

2. Description of the Related Art In recent years, various types of image display devices (displays), for example, liquid crystal display (LCD), plasma display panel (PDP), electroluminescence display (ELD), cathode ray tube display (CRT), fluorescent display Tubes and field emission displays have been developed and devices incorporating them have been put into practical use. These image display devices have various problems, for example, problems such as insufficient color purity and color separation of the display element, a problem that the contrast is reduced due to the background being reflected on the display, infrared rays and electromagnetic waves caused by the display element. Have the problem of external leakage. For each of these problems, it has been proposed to use, for example, a visible filter for color separation, an antireflection film, an infrared shielding filter, an electromagnetic shielding filter, or the like on the front surface of the display. However, each of these filters requires various tasks depending on the type of display. For example, a visible filter for color separation needs to form a sharp absorber according to the characteristics of the display element. In addition to this, heat resistance such as kneading in glass and enhancement of physical properties are required. In addition, antireflection coatings need to be multilayered in order to obtain an ideal reflectance in the entire visible light range. Accompanied by Therefore, if an optical filter placed in front of a display is to have many functions, in addition to the characteristics required for each function filter, there is a restriction that one function must not interfere with the other functions. . Therefore, multifunctional optical filters have not yet been put to practical use.

[0003]

In developing a multifunctional optical filter, it is necessary to solve various problems depending on the functions to be combined. As an example, a case will be described as an example in which an antireflection function is combined with a visible filter for color correction. Attempts have been made to impart the function of a visible filter by coloring a member constituting the antireflection film, for example, a transparent support or a hard coat layer. However, in this case, the types of dyes and pigments that can be added to the transparent support and the hard coat layer are very limited. The reason for this is that the transparent support is usually usually made of plastic, or even of glass. Therefore, 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. On the other hand, the hard coat layer is generally a layer containing a crosslinked polymer. The crosslinking reaction of the polymer is performed by heating or irradiating light or the like after the application of the layer. This is because there are many dyes and pigments that fade under the reaction conditions for the crosslinking. Furthermore, 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 for the above reasons, it is difficult to perform appropriate correction. Another problem is that a thick plastic plate or a glass plate is used for the support, so that it is bulky and heavy, and it is difficult to secure an installation place and to handle it.

In order to avoid the above-mentioned restrictions, it is easy to add a dye or pigment to a polymer layer which can be formed under mild conditions, instead of a transparent support or a hard coat layer, and provide a colored layer as an independent visible filter layer. Conceivable. However, unlike the hard coat layer, the colored polymer layer has a low affinity for the transparent support (plastic or glass) and the low refractive index layer in the antireflection film, and has a disadvantage that a failure such as peeling is likely to occur. Also, separately from this, the visible filter layer itself for correcting the color of the image display device appears to be colored, and the visibility of the image is poor, the color correction is not sufficient, and the color of the screen when the image is not displayed is changed. There is a problem that it is not preferred, and an achromatic visible filter has been desired. in this way,
It is necessary that the material of a multifunctional optical filter be restricted and that the arrangement of the filter layers for each function be devised. Accordingly, it is an object of the present invention to provide a multifunctional optical filter which is excellent in manufacturability, is light in weight without being bulky, has an achromatic color and is excellent in color correction function, and a front plate and an image display device using the same. It is.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object of the present invention is as follows.
The following optical filters according to items 1) to 5), the front plate according to item 16), and the optical filters according to items 15) to 17).
Has been achieved by the image display device described in (1). Listed below are preferred embodiments. 1) At least one side of the transparent support had a visible filter layer, an optical filter having the visible filter layer was provided on the front surface of the image display device, and an optical filter was provided according to the method for measuring a reflective object described in JIS Z 8722. An optical filter characterized in that a color measured in front of an image display device and illuminated with standard light D65 is in a range represented by the following formula (I). 0 ≦ | a * | ≦ 10, 0 ≦ | b * | ≦ 10 (I) Here, a * and b * represent a * and b * values in the CIE 1976 L * a * b * color space, and JIS Z It shall be displayed according to 8729. 2) the visible filter layer has an absorption maximum having a transmittance of 0.01 to 50% in a wavelength range of 560 to 620 nm;
Item 1. The optical filter according to item 1), wherein the average transmittance in a wavelength range of 380 to 440 nm is 70% or less. 2) the visible filter layer has an absorption maximum having a transmittance of 0.01 to 50% in a wavelength range of 560 to 620 nm;
Item 1. The optical filter according to item 1, wherein the average transmittance in the wavelength range of 640 to 780 nm is 70% or less. 3) The visible filter layer has an absorption maximum having a transmittance of 20 to 85% in a wavelength range of 500 to 550 nm, and a transmittance of 0.01 to 50% in a wavelength range of 560 to 620 nm.
Wherein the average transmittance in the wavelength range of 380 to 440 nm is 70% or less.
An optical filter according to item 1. 4) The visible filter layer has an absorption maximum having a transmittance of 20 to 85% in a wavelength range of 500 to 550 nm, and has a transmittance of 0.01 to 50% in a wavelength range of 560 to 620 nm.
Item 1. The optical filter according to Item 1), which has an absorption maximum and an average transmittance of 70% or less in a wavelength range of 640 to 780 nm. 5) The visible filter layer has an absorption maximum having a transmittance of 20 to 85% in a wavelength range of 460 to 500 nm and a wavelength range of 500 to 550 nm in each case.
Item 1) The optics according to Item 1), wherein the transmittance has an absorption maximum of 0.01 to 50% in the wavelength range of 0 nm, and the average transmittance in the wavelength range of 380 to 440 nm is 70% or less. filter. 6) The visible filter layer has an average transmittance of 70% or less in a wavelength range of 380 to 440 nm and an average transmittance of 70% or less in a wavelength range of 640 to 780 nm. Optical filter. 7) The optical filter according to any one of Items 1) to 6), wherein the visible filter layer is a visible filter layer containing a polymer binder. 8) The optical filter according to any one of Items 1) to 7), wherein the material of the transparent support is a biaxially stretched film. 9) The optical filter according to any one of items 1) to 8), wherein the material of the transparent support is polyester, polycarbonate, or polyarylate. 10) The optical filter according to any one of items 1) to 9), further comprising a low refractive index layer having a refractive index lower than that of the transparent support on at least one side of the transparent support. 11) On one side of the transparent support, one or two or more undercoat layers substantially composed of a polymer having an elastic modulus at 25 ° C. of 1,000 MPa or less and 1 MPa or more, and a visible filter layer are sequentially provided. To 11) The optical filter according to any one of the above. 12) An undercoat layer substantially composed of a polymer having an elastic modulus at 25 ° C. of 1,000 MPa or less and 1 MPa or more is provided between the low refractive index layer and the transparent support. The optical filter according to (1). 13) The undercoat layer provided on the low refractive index layer side provided on the transparent support comprises two layers, and the first undercoat layer adjacent to the transparent support comprises a styrene-butadiene copolymer. Item 10. The optical filter according to Item 10) or 12), wherein the second undercoat layer adjacent to the first undercoat layer is formed of an acrylic resin layer. 14) The optical filter is used for a plasma display panel (PDP).
3) The optical filter for PDP according to any one of the above. (15) The PDP according to any one of (1) to (14), wherein the optical filter is used by being directly attached to a panel surface of a plasma display panel (PDP).
For optical filters. 16) An image display device using the optical filter according to any one of items 1) to 14). 17) A front panel of a plasma display panel using the optical filter according to any one of Items 1) to 14). 18) The image display device according to item 16), which is a plasma display panel.

A typical layer structure of an optical filter used in the image display device of the present invention will be described with reference to the drawings. Hereinafter, a layer configuration when used as an optical filter for a cathode ray tube display (CRT) and a plasma display panel (PDP) or a front plate having an optical filter will be described.

FIG. 1 is a conceptual sectional view of a case where an optical filter C or a front plate D of the present invention is used on the front surface of a main body A of a cathode ray tube display (CRT) or a plasma display panel (PDP). FIG. 1A shows a case where an optical filter C including a plastic support in which various filter layers and antireflection layers are provided on one side or both sides of the support of the optical filter is directly attached to the main body A. (b) is a concept in the case where there is a space between the main body A and the front plate D, and an optical filter comprising various filter layers and an antireflection layer or a part C thereof is provided on both surfaces of the support of the front plate. FIG. In the present invention, the term "front plate" refers to an optical filter composed of various filter layers or antireflection layers or a part thereof laminated on one or both sides of another support (plastic or transparent glass or the like). Which is installed between the display device and the observer, preferably immediately before the display device.

FIG. 2 is a schematic sectional view of the layer structure of the optical filter and the front plate. 2 (a) and 2 (b) show FIG.
FIG. 2C shows an example of the layer configuration of the optical filter corresponding to the arrangement of FIG. 1A, and FIGS. 2C and 2D show examples of the layer configuration of the front plate corresponding to the arrangement of FIG. In FIG. 2A, it is preferable to provide an undercoat layer between the transparent support and the hard coat layer and between the transparent support and the filter layer in order to obtain a sufficient adhesive strength. In FIG. 2B, it is preferable to provide an undercoat layer in order to obtain a sufficient adhesive strength between the transparent support and the hard coat layer and between the transparent support and the electromagnetic wave and infrared ray shielding layer. Between the filter layer and the image display device body,
For example, it can be easily bonded by using a commercially available acrylic pressure-sensitive adhesive. In FIGS. 2C and 2D, it is preferable to provide an undercoat layer between the transparent support and the filter layer and between the transparent support and the antireflection layer in order to obtain a sufficient adhesive strength. The optical filter of the present invention is shown in FIGS.
In any of the configurations, when the image display device as a final finished product is viewed from the front side, the color is preferably close to achromatic. As for the degree of achromatic color, an optical filter is provided on the front of the image display device, colorimetry is performed on the front of the image display device provided with an optical filter according to the measuring method of a reflective object described in JIS Z 8722, and illumination is performed with standard light D65. In this case, the color is preferably in a range represented by the following formula (I). 0 ≦ | a * | ≦ 10, 0 ≦ | b * | ≦ 10 (I) Here, a * and b * represent a * and b * values in the CIE 1976 L * a * b * color space, and JIS Z It shall be displayed according to 8729. More preferably, it is in the range of −5 ≦ a * ≦ 5 and −10 ≦ b * ≦ 0.

The materials constituting the optical filter of the present invention and the front plate using the same and the structure thereof will be described below. (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, polybutylene terephthalate) , Polyarylate (eg bisphenol A
And phthalic acid), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polyethylene, polypropylene, polymethylpentene), acrylic (polymethylmethacrylate), polysulfone, polyethersulfone, polyetherketone, polyether Includes imides and polyoxyethylene. Polyester, polycarbonate and polyarylate are preferred. Most preferred are polyethylene terephthalate and polyethylene naphthalate. The thickness of the support is preferably 5 μm or more and 5 cm or less, and 25 μm or more and 1 cm or less.
And more preferably 80 μm or more and 1.2 μm or less.
Most preferably, it is not more than mm. The transmittance of the transparent support is preferably 80% or more, and more preferably 86% or more. The haze is preferably at most 2%, more preferably at most 1%.
The refractive index is preferably from 1.45 to 1.70.

[0010] An infrared absorber or an ultraviolet absorber may be added to the transparent support. The amount of infrared absorber added
The content is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight of the transparent support. Further, as a slipping agent, particles of an inert inorganic compound may be added to the transparent support. Examples of inorganic compounds include S
_{iO 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 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 corona discharge treatment is more preferred.

(Visible Filter Layer) The visible filter layer is a layer that selectively absorbs visible light (wavelength range: 380 to 780 nm). The thickness of the filter layer is preferably from 0.1 μm to 5 cm, and from 0.5 μm to 1 cm
More preferably, it is most preferably 1 μm to 7 mm. The filter layer is 560 to 620
It is preferable to have an absorption maximum in the wavelength range of nm (560 nm to 620 nm, the same applies hereinafter), and more preferable to have an absorption maximum in the wavelength range of 580 to 600 nm. Further, it may have an absorption maximum in a wavelength range of 500 to 550 nm. The transmittance in the wavelength range of 500 to 550 nm is preferably in the range of 20 to 85%, more preferably in the range of 40 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 at the absorption maximum) is preferably 30 to 300 nm, more 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 0.01 to 50%, more preferably in the range of 0.01 to 40%. The absorption maximum in the wavelength range of 560 to 620 nm is set in order to selectively cut the sub-band that reduces the color purity of the red phosphor. In a PDP, unnecessary light emission near 585 nm emitted by the excitation of neon is cut off, and at the same time light on the short wavelength side from the red phosphor is cut off. By separating the absorption maximum according to the present invention, without adversely affecting the color tone of the green phosphor,
Light can be selectively cut. 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 5 to 200 nm, and more preferably 10 to 100 nm.
Is more preferable, and most preferably 12 to 50 nm. The transmittance at the absorption maximum in the wavelength range of 460 to 500 nm is preferably in the range of 20 to 85%, more preferably in the range of 40 to 85%. The absorption maximum in the wavelength range of 460 to 500 nm is set to suppress coloring of the visible filter and to make the filter achromatic. It is preferable to sharpen the peak of the absorption spectrum in order to reduce the adverse effect on the brightness and the color correction function. Specifically, the half width at the absorption maximum in the wavelength range of 460 to 500 nm is preferably 5 to 200 nm, more preferably 10 to 150 nm, and most preferably 15 to 100 nm.

The average transmittance T ₁ in the wavelength range from 380 to 440 nm is defined by the following equation.

(Equation 1) Where T (375 + 5n) is the wavelength (375 + 5n) nm
Shows the transmittance (%) of the sample.

The average transmittance in the wavelength range of 380 to 440 nm is preferably 70% or less, more preferably 60% or less. More specifically, the average transmittance in the wavelength range of 380 to 440 nm is 1 to 7
0% (meaning “1% or more and 70% or less” and the same in the present application) is preferable, and more preferably 5 to 60%.
%, Most preferably 10 to 50%. 38
Absorption in the wavelength range of 0 to 440 nm is set to suppress the bluish coloring of the visible filter itself and to make it achromatic.

The average transmittance in the wavelength range of 640 to 780 nm is defined by the following equation.

(Equation 2) In the formula, T (635 + 5n) represents the transmittance (%) at the wavelength (635 + 5n) nm.

The average transmittance in the wavelength range of 640 to 780 nm is preferably 70% or less, more preferably 60% or less. More specifically, the average transmittance is preferably 1 to 70%, more preferably 5 to 70%.
To 60%, most preferably 10 to 50%. The absorption in the wavelength range of 640 to 780 nm is set to suppress reddish coloring of the visible filter itself and to make it achromatic.

The wavelength range of 380 to 440 nm and 640
Adjustment of the average transmittance in the wavelength range of from 780 nm to 780 nm is performed by adjusting one or both ranges to the above range so that the color of the filter itself approaches an achromatic color as much as possible. The color of the filter itself is determined by the position of the absorption maximum in the wavelength range of 560 to 620 nm and its transmittance, the position of the absorption maximum in the wavelength range of 500 to 550 nm and its transmittance, the positional relationship between the two absorptions, and the intensity ratio of the absorption intensity. Subtle changes. Therefore, 38
It is necessary to adjust the transmittance in the wavelength range of 0 to 440 nm and the wavelength range of 640 to 780 nm according to the filter design specifications. When adjusting the transmittance to reduce the luminance or minimize the adverse effect on the color correction function, the change in the transmittance around 440 nm is desirably as steep as possible, and the transmittance at 445 nm is preferably It is at least 75%, more preferably at least 80%. Similarly, the change in transmittance around 640 nm is desirably as steep as possible, and the transmittance at 635 nm is preferably 75% or more, more preferably 80% or more.

In order to provide the above absorption spectrum,
A filter layer can be formed using a coloring matter (dye or pigment). As the dye having an absorption maximum in the wavelength range of 500 to 550 nm, a squarylium-based, azomethine-based, cyanine-based, oxonol-based, anthraquinone-based, azo- or benzylidene-based compound is preferably used. As azo dyes, GB 539703,
Many azo dyes described in US Pat. No. 5,756,691, US Pat. No. 2,956,879 and Hiroshi Horiguchi, “Review Synthetic Dyes”, published by Sankyo Publishing Co. can be used. Wavelength 500-550n
Examples of the dye having an absorption maximum in the range of m are shown below.

[0020]

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[0021]

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[0022]

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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 6
Examples of the dye having the absorption maximum in the wavelength range of 20 nm are shown below.

[0024]

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[0025]

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[0026]

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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 a longer wavelength side, and the peak becomes sharp. Therefore, the dye having an absorption maximum in the wavelength range of 500 to 550 nm has an aggregate of 560 to 620 nm.
Some have an absorption maximum in the range of nm. When such a dye is used in a state of partially forming an aggregate, 50%
An absorption maximum can be obtained in both the wavelength range of 0 to 550 nm and the wavelength range of 560 to 620 nm. Examples of such dyes are shown below.

[0028]

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As the dye having an absorption in the wavelength range of 460 to 500 nm, methine, anthraquinone, quinone, diphenylmethane dye, triphenylmethane dye, xanthene dye, azo and azomethine compounds are preferably used. Examples of the methine series include cyanine series, merocyanine series, oxonol series, arylidene series, and styryl series. 460 to 500n
Examples of the dye having absorption in the wavelength range of m are shown below.

[0030]

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As the dye having an absorption in the wavelength range of 380 to 440 nm, methine, anthraquinone, quinone, diphenylmethane dye, triphenylmethane dye, xanthene dye, azo and azomethine compounds are preferably used. Examples of the methine series include cyanine series, merocyanine series, oxonol series, arylidene series, and styryl series. 380 to 440n
Examples of the dye having absorption in the wavelength range of m are shown below.

[0032]

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Dyes having absorption in the wavelength range of 640 to 780 nm include cyanine, squarylium, azomethine, xanthene, oxonol, azo, and the like.
Anthraquinone, triphenylmethane, xanthene, Cu-phthalocyanine, phenothiazine or phenoxazine compounds are preferably used. 6
Examples of dyes having absorption in the wavelength range of 40 to 780 nm are shown below.

[0034]

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[0035]

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[0036]

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In the filter layer, two or three or more dyes having the same or different wavelength absorption ranges described above can be used in combination.

(Binder) The filter layer preferably contains a suitable binder in addition to the dye, and particularly preferably contains a polymer binder. Natural polymers (eg,
Use of 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) as the polymer binder Can be.
Particularly preferred are hydrophilic polymers (the above-mentioned natural polymers, polyvinyl butyral, polyvinyl pyrrolidone, polyvinyl alcohol, and water-soluble polyamide).

(Undercoat layer) In the present invention,
An antireflection layer, a filter layer, an infrared shielding layer, and an electromagnetic wave shielding layer described below can be provided on the support. In this case, one or more layers are provided between the support and these functional layers. Undercoat layer can be provided. The undercoat layer is preferably a soft polymer having an elastic modulus at 25 ° C. of 1 MPa or less at 1000 MPa, preferably 5 MPa or more at 800 MPa, more preferably 10 MPa or more at 500 MPa. The thickness is preferably 2 nm or more and 2
0 μm or less, more preferably 5 nm or more and 5 μm or less,
Most preferably, it is 50 nm or more and 1 μm or less. Preferred polymers used in the subbing layer of the present invention are vinyl chloride, vinylidene chloride, vinyl acetate, butadiene, neoprene, styrene, chloroprene, acrylates, methacrylates, acrylonitrile or methyl vinyl ether alone. A copolymer (copolymer) obtained by polymerization or copolymerization of two or more monomers selected from the group consisting of these vinyl monomers.

(Anti-reflection layer) The anti-reflection layer means a layer having a regular reflectance of 3.0% or less, and preferably a layer having a regular reflectance of 1.8% or less. It is usually useful to provide a low refractive index layer as the antireflection layer. 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 preferably from 1.20 to 1.55, more preferably from 1.30 to 1.50. The thickness of the low refractive index layer is 50 to 400 nm.
Or less, more preferably 50 to 200 nm. The low refractive index layer is a layer made of a fluorine-containing polymer having a low refractive index (JP-A-57-3452).
No. 6, JP-A-3-130103 and 6-115023
And JP-A-8-313702 and JP-A-7-168004), and a layer obtained by a sol-gel method (Japanese Unexamined Patent Publication No.
No. 208811, No. 6-299091, No. 7-168
No. 003) or a layer containing fine particles (JP-B-60-59250, JP-A-5-13021, JP-A-6-56478, JP-A-7-92306, and 9-288).
No. 201). 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 middle / high refractive index layer is a layer having a higher refractive index than the undercoat layer of the present invention.
By using the high refractive index layer together, a high antireflection effect can be obtained in a wider range than when only the low refractive index layer is used. The refractive index of the high refractive index layer is preferably from 1.65 to 2.40, and more preferably from 1.70 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 1.50 to 1.9.
It is preferably 0. The thickness of the middle / high refractive index layer is 5
It is preferably from 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 having a relatively high refractive index. Examples of polymers having a high refractive index include polystyrene, styrene copolymer,
Included are polycarbonates, melamine resins, phenolic resins, epoxy resins and polyurethanes obtained by reacting cyclic (alicyclic or aromatic) isocyanates with polyols. Other cyclic (aromatic, heterocyclic, alicyclic)
Polymers having a group or 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) of 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.

(Electromagnetic Wave Shielding Layer and Infrared Shielding Layer)
In the present invention, the layer having an electromagnetic wave blocking effect has a surface resistance of 0.01 to 500 Ω / □, more preferably 0.01 to 10 Ω / □. To provide an electromagnetic wave shielding effect,
It is preferable to use a transparent conductive layer so as not to lower the visible light transmittance of the front plate. As the transparent conductive layer, a metal layer,
Examples include a metal oxide layer and a conductive polymer layer. Examples of the metal forming the transparent conductive layer include silver, palladium, gold, platinum, rhodium, aluminum, iron, cobalt, nickel, copper, zinc, ruthenium, tin, tungsten, iridium, lead alone and alloys thereof. But preferably silver, palladium, gold,
Platinum, rhodium alone or an alloy thereof. Here, an alloy of silver and palladium is preferable. At this time, the silver content is preferably 60% to 99%, more preferably 80% to 98%. The thickness of the metal layer is preferably 1 to 100 nm, more preferably 5 to 40 nm, and most preferably 10 to 30 nm. If the film thickness is less than 1 nm, the electromagnetic wave shielding effect is poor, and if it exceeds 100 nm, the transmittance of visible light decreases. Examples of the metal oxide forming the transparent conductive layer include tin oxide, indium oxide, antimony oxide, zinc oxide,
ITO, ATO, etc. can be mentioned. This film thickness is preferably from 20 to 1000 nm. More preferably 40
１００100 nm. It is also preferable to use the metal transparent conductive layer and the oxide transparent conductive layer together. It is also preferable that a metal and a conductive metal oxide coexist in the same layer. A transparent oxide layer can be laminated to protect the metal layer, prevent oxidative deterioration, and increase visible light transmittance. This transparent oxide layer may or may not be conductive. Examples of the transparent oxide layer include thin films of oxides of divalent to tetravalent metals, zirconium oxide, titanium oxide, magnesium oxide, silicon oxide, aluminum oxide, and metal alkoxide compounds. The method for forming the transparent conductive layer and the transparent oxide layer is not particularly limited, and any processing method can be selected. For example, any known technique such as a sputtering method, a vacuum deposition method, an ion plating method, a plasma CVD method or a PVD method, and application of ultrafine particles of a corresponding metal or metal oxide can be used. As another method for providing an electromagnetic wave shielding effect, there is a method using a metal mesh. This is a metal in which a thin metal is arranged in a grid pattern on the entire surface of the support, and is slightly inferior in transparency to the transparent conductive layer, but has excellent conductivity and excellent electromagnetic wave shielding ability. This method can be used alone or in combination with a transparent conductive layer, and the electromagnetic wave shielding ability can be adjusted according to the purpose.

The infrared shielding effect in the present invention is 80%.
It refers to the function of shielding a line spectrum in the near infrared region from 0 to 1200 nm. As for the line spectrum shielding characteristics in the near infrared region, the transmittance at 800 nm is preferably 15% or less, and the transmittance at 850 nm is preferably 5% or less. To impart this infrared shielding effect, a method of mixing a near infrared absorbing compound with a transparent plastic support can be used. For example, a resin composition containing a copper atom (JP-A-6-118228), a resin composition containing a copper compound and a phosphorus compound (JP-A-62-5190), a copper compound, and a thiourea derivative are contained. It can be easily produced by forming a resin composition (JP-A-6-73197), a resin composition containing a tungsten compound (US Pat. No. 3,647,729), and the like. As another method, similarly to the visible filter layer, there is a method of forming an infrared shielding filter layer using a coloring matter (dye or pigment). As the dye having absorption in the near infrared region, a cyanine compound is preferably used. Examples of the dye having an absorption maximum in a wavelength range of about 800 nm to 1200 nm are shown below.

[0045]

Embedded image A method of forming silver into a transparent film is inexpensive and preferable as a method of providing an infrared shielding effect in addition to the electromagnetic shielding. For the near-infrared shielding layer, two or three or more types of means described above having substantially the same or different wavelength absorption ranges can be used in combination.

(Inorganic Glass Substrate) The thickness of the inorganic glass substrate used for the front plate of the present invention is preferably 1 mm to 5 mm, more preferably 1.5 mm to 4.5 mm, and preferably 2 mm.
Most preferably 4 mm to 4 mm. As a material, tempered glass is preferable from the viewpoint of protecting the panel body and the viewpoint of safety. (Other layers) In the present invention, a hard coat layer, a lubricating layer,
An antifouling layer, an antistatic layer or an intermediate layer may be provided. The hard coat layer preferably contains a cross-linked polymer. The hard coat layer can be formed using an acrylic, urethane, epoxy, or siloxane-based polymer, oligomer, or monomer (eg, an ultraviolet curable resin). A silica-based filler can be added to the hard coat layer. 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. Alternatively, an antifouling layer can be provided on the outermost surface of the antireflection film. The antifouling layer lowers the surface energy of the antireflection layer and makes it difficult to adhere to hydrophilic and lipophilic stains. In addition, the antifouling layer can be formed using a fluorine-containing polymer. The thickness of the antifouling layer is 2 nm to 10
It is 0 nm, preferably 5 nm to 30 nm.

In the present invention, the surface can be provided with an anti-glare function (a function of scattering incident light on the surface to prevent a scene around the film from being reflected on 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 anti-reflection layer having an anti-glare function is generally 3
It has a haze of 乃至 30%.

The antireflection layer (low refractive index layer), filter layer, infrared ray or electromagnetic wave shielding layer, undercoat layer, hard coat layer, lubricating layer, antifouling layer, and other layers are formed by a general coating method. be able to. 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. Regarding the simultaneous coating method, see US Pat.
No. 2941898, No. 3508947, No. 35
No. 26528, and the description in Yuji Harazaki, “Coating Engineering”, p. 253 (published by Asakura Shoten in 1973). The method for forming the antireflection layer and the infrared or electromagnetic wave shielding layer in the present invention includes sputtering, vacuum evaporation, ion plating, plasma CVD, and PVD. It can be appropriately selected according to the improvement.

In the present invention, the constituent materials of the present invention (for example, the type of the material of the support, the type of the dye, the material of the undercoat layer, the material of the infrared or electromagnetic wave shielding layer, and the low refractive index polymer for the antireflection layer) Two or more selected from various types (e.g., type, etc.) and various characteristics (e.g., transmittance of a visible filter, surface resistance of an electromagnetic wave shielding layer, infrared transmittance of an infrared shielding layer, elastic modulus range of an undercoat layer, etc.). The preferred constituent materials or combinations of properties can also be used as preferred embodiments of the present invention.

(Applications of Optical Filter and Front Plate of the Present Invention) The optical filter and front plate of the present invention can be used for a liquid crystal display (LCD) and a plasma display panel (PD).
P), electroluminescent display (EL)
D) or an image display device such as a cathode ray tube display device (CRT). Particularly when the optical filter and the front plate of the present invention are used as an optical filter and a front plate of a plasma display panel (PDP) and a cathode ray tube display (CRT), a remarkable effect can be 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. The optical filter and the front panel are located on the front of the main body of the plasma display so as to protect the main body. It is preferable that the optical filter and the front plate have sufficient strength to protect the main body. The optical filter and the front plate of the present invention can be used with a gap from the plasma display main body, or can be used directly attached to the plasma display main body. Plasma display panels (PDPs) are already commercially available. The plasma display panel is described in JP-A-5-205643 and JP-A-9-306366.

[0051]

Example 1 (Formation of an undercoat layer) After a corona treatment was applied to both sides of a transparent biaxially stretched polyethylene terephthalate film having a thickness of 170 μm, both sides had a refractive index of 1.55, an elastic modulus at 25 ° C. of 100 MPa, and a glass transition. A latex made of styrene-butadiene copolymer at a temperature of 37 ° C. (manufactured by Zeon Corporation, LX407C5) was applied to form an undercoat layer. The thickness after drying is 300 nm on the surface on which the filter layer is provided, and 15
It was applied so as to have a thickness of 0 nm.

(Formation of Second Undercoat Layer) A gelatin aqueous solution containing acetic acid and glutaraldehyde is applied on the undercoat layer on the surface on which the filter layer is to be provided so as to have a dried thickness of 110 nm, and the antireflection layer is formed. On the undercoat layer on the surface to be provided, a refractive index of 1.50, an elastic modulus of 120 MPa at 25 ° C.,
Acrylic latex with glass transition temperature of 50 ° C (HA1
6, Nippon Acrylic Co., Ltd.) was applied to a thickness of 20 nm after drying to form a second undercoat layer.

(Formation of Low Refractive Index Layer as Antireflection Layer)
1.3 g of t-butanol was added to 2.50 g of a reactive fluoropolymer (JN-7219, manufactured by Nippon Synthetic Rubber Co., Ltd.)
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 dried and cured at 120 ° C. for 15 minutes to form a low refractive index layer.

(Formation of visible and near-infrared filter layers)
180 g of a 10% by weight aqueous solution of gelatin was added to a dye (b1
4) 0.05 g, 0.07 g of dye (e2) and 0.05 g of dye (f2) were dissolved, stirred at 40 ° C. for 30 minutes, and filtered with a 2 μm polypropylene filter. The obtained coating liquid for a filter layer is applied on the second undercoat layer of the transparent support opposite to the side on which the low refractive index layer is applied, so that the dry film thickness becomes 3.5 μm, and at 120 ° C. 1
After drying for 0 minute to form a visible and near-infrared filter layer, a support having an antireflection layer and visible and near-infrared filter layers was prepared.

When the visible light spectral transmittance of the above support was examined, it had an absorption maximum at 586 nm, and the transmittance at the absorption maximum was 9%. The half width of the absorption maximum was 30 nm. The change in transmittance around 640 nm is sharp,
The transmittance at 35 nm is 81%, and the transmittance at 645 nm is about 30%.
% And about 13% at 650 nm. T ₂ is about 42%
Met.

(Coating of Electromagnetic Wave and Infrared Shielding Layer and Antireflection Layer on Transparent Glass Support) Silver was sputtered on the surface of a colorless and transparent tempered glass plate having a thickness of 3 mm to have a surface resistance of 2.2 Ω / □. A film having a thickness of about 13 nm was applied so as to form a film. The optical film thickness (product of the refractive index and the film thickness) becomes 130 to 140 nm on the thus coated silver film in the order of MgF ₂ , then SiO ₂ , TiO ₂ , and MgF ₂ using a vacuum evaporation method. Was deposited as follows. When the reflectance of this antireflection film was measured, the average reflectance in the wavelength range of 500 to 600 nm was 0.6%. (Preparation of Front Plate) An acrylic pressure-sensitive adhesive having a thickness of 30 was applied to the filter layer surface of a polyethylene terephthalate film coated with a low refractive index layer and visible and near infrared filter layers.
It was applied in a thickness of μm, and was adhered to the surface of the glass plate on which the antireflection layer was deposited, opposite to the surface on which the antireflection layer was deposited, to produce a front plate of the present invention.

Comparative Example 1 A front plate was produced in exactly the same manner as in Example 1 except that the dye (e2) was not added to the visible filter layer.

Example 2 (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 as Antireflection Layer)
A low refractive index layer was formed in the same manner as in Example 1.

(Formation of visible and near-infrared filter layers)
A filter layer was formed in the same manner as in Example 1 to prepare a support provided with an antireflection layer and visible and near-infrared filter layers.

(Coating of Electromagnetic Wave and Infrared Shielding Layer, Antireflection Layer on Transparent Glass Support) TiO ₂ and silver were coated with TiO ₂ / silver / T on the surface of a 3 mm thick colorless transparent tempered glass plate.
The order of iO ₂ / silver / TiO ₂ (thickness 21/13/50/1
(3/21 nm) to form a five-layer film by sputtering. The surface resistance was 2.0Ω / □. When the reflectance of this antireflection film was measured, the average reflectance in the wavelength range of 500 to 600 nm was 1.1%.

(Preparation of Front Plate) Polyethylene terephthalate having an antireflection layer and a visible and near-infrared filter layer applied thereon in the same manner as in Example 1 on a glass transparent support provided with an electromagnetic wave and infrared shielding layer and an antireflection layer A film was stuck to produce a front plate.

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 as Antireflection Layer)
A low refractive index layer was formed in the same manner as in Example 1.

(Formation of visible and near-infrared filter layers)
Dye (b7) was added to 180 g of a 10% by weight aqueous solution of gelatin.
0.05 g, dye (a2) 0.15 g, dye (d1)
Dissolve 0.06 g and 0.05 g of dye (f2),
After stirring at 40 ° C. for 30 minutes, the mixture was filtered with a 2 μm polypropylene filter. The obtained coating solution for a filter layer was applied in the same manner as in Example 1 to prepare a support provided with an antireflection layer and a filter layer.

When the visible light spectral transmittance of the support was examined, the support had absorption maximums at 535 nm and 595 nm, and the transmittance at the absorption maximum was 70% at 535 nm.
The absorption maximum at 95 nm was 25%. As for the half width of the absorption maximum, the absorption maximum at 535 nm was 71 nm, and the absorption maximum at 595 nm was 29 nm. The change in transmittance around 440 nm is steep, and the transmittance at 445 nm is 75%,
It was about 27% at 35 nm and about 11% at 430 nm. T ₁ is about 33%.

(Preparation of Front Plate) An anti-reflection layer and visible and near-infrared light were formed on a glass transparent support coated with an electromagnetic wave and infrared shielding layer and an anti-reflection layer in the same manner as in Example 2. A polyethylene terephthalate film coated with a filter layer was attached to produce a front plate.

Comparative Example 2 A front plate was prepared in exactly the same manner as in Example 3 except that the dye (d1) was not added to the visible filter layer. (Evaluation of color of front panel) The front panel of the plasma display panel (PDS4202J-H, manufactured by Fujitsu Ltd.) was removed, and the front panels produced in Examples 1 to 3 and Comparative Examples 1 and 2 were replaced with an antireflection layer. Then, the surface to which the polyethylene terephthalate film coated with the visible and near-infrared filter layers was attached was attached to the plasma display panel body side. The color of the front surface of the plasma display to which the front plates prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were attached was measured with a spectroradiometer (SR-2A manufactured by Topcon Corporation). The results of the measurement and the results of the visual evaluation are shown in Table 1 below. Table 1 The one with the front plate produced in Comparative Example 1 was reddish, and the one with the front plate produced in Comparative Example 2 was bluish, and the TV screen color was uncomfortable.

(Evaluation of Filter Function) The electromagnetic wave and near-infrared shielding layer were connected to the metal ground on the back of the plasma display panel, and the voltage induced in the electromagnetic wave and near-infrared shielding layer by the electromagnetic wave radiated from the plasma display panel was measured. Conduction to ground was performed and the function was evaluated. As evaluation items, measurement of electromagnetic wave and infrared shielding ability, contrast of a displayed image, and evaluation of color reproducibility by visual observation were performed. The electromagnetic wave shielding ability was 10 frequency in each of Examples 1 to 3 and Comparative Examples 1 and 2.
A minimum of 9 dB or more was obtained in the range of MHz to 200 MHz, and the external leakage level of electromagnetic waves regulated by information processing devices and the like was achieved. The line spectrum shielding ability in the near infrared region is about 8% at 800 nm and 3% at 850 nm.
% Or less, preventing interference with infrared remote control devices installed in the vicinity. Contrast and visual color reproducibility were significantly improved in all of Examples 1 to 3. The contrast was 10: 1 before the front plate was replaced, but in each of the embodiments, the contrast was 15: 1.
Met. In each of the examples, compared to before the replacement of the front panel, red with orange is pure red, greenish blue is bright blue, and that yellowish white has been improved to pure white. confirmed. In Comparative Examples 1 and 2, the former was reddish, the latter was bluish depending on the direction of reflection of external light, and the latter was not as improved as in the examples.

Example 4 (Formation of Undercoat Layer) After a corona treatment was applied to both sides of a transparent biaxially stretched polyethylene terephthalate film having a thickness of 175 μm, both sides had a refractive index of 1.55, an elastic modulus of 100 MPa at 25 ° C., and a glass transition temperature. A latex (LX407C5, manufactured by Zeon Corporation) of styrene-butadiene copolymer at 37 ° C. was applied 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 provided and 200 nm on the surface on which the hard coat layer was provided.

(Formation of Hard Coat Layer Second Undercoat Layer) The refractive index of 1.5 was formed on the undercoat layer on which the hard coat layer was to be provided.
An acrylic latex (HA16, manufactured by Nippon Acrylic Co., Ltd.) having an elastic modulus of 120 MPa at 0 and 25 ° C. and a glass transition temperature of 50 ° C. was applied to a thickness of 50 nm after drying to form a second undercoat layer.

(Coating of Hard Coat Layer) One side (styrene-butadiene copolymer latex 2) of a biaxially stretched polyethylene terephthalate film having a second undercoat layer formed thereon
00 nm, surface of acrylic latex 50 nm as an undercoat layer), as a hard coat layer, by an ultraviolet curing method,
Dipentaerythritol hexaacrylate layer (film thickness 1
0 μm). The method used for the formation was a conveyor-type ultraviolet curing method, which was performed using a high-pressure mercury lamp for 750 m.
Irradiation was performed at an energy density of J / cm ² . (Coating of electromagnetic wave and infrared shielding layer and anti-reflection layer) TiO ₂ and silver are coated on the surface of the hard coat layer with TiO ₂ / silver / Ti
The order of O ₂ / silver / TiO ₂ (film thickness 22/13/51/14)
/ 21 nm) to form a five-layer film by sputtering. The surface resistance was 2.0Ω / □. When the reflectance of this film surface was measured, the average reflectance in the wavelength range of 500 to 600 nm was 1.1%.

(Formation of Second Undercoat Layer of Filter Layer) Acetic acid and glutar were placed on the undercoat layer of the biaxially stretched polyethylene terephthalate film opposite to the surface on which the electromagnetic wave and infrared shielding layer and antireflection layer were provided. An aqueous solution of gelatin containing aldehyde was applied to a thickness of 100 nm after drying to form a second undercoat layer.

(Formation of visible and near-infrared filter layers)
180 g of a 10% by weight aqueous solution of gelatin was added to a dye (b1
4) 0.05 g, 0.07 g of dye (e4) and 0.05 g of dye (f2) were dissolved, stirred at 40 ° C. for 30 minutes, and filtered with a 2 μm polypropylene filter. The obtained coating liquid for a filter layer was applied onto the second undercoat layer so that the dry film thickness became 3.5 μm,
After drying at 10 ° C. for 10 minutes to form a filter layer, a support having a hard coat layer, an electromagnetic wave and infrared shielding layer, and an anti-reflection layer on one side, and a visible and near-infrared filter layer on the other side was prepared. .

When the visible light spectral transmittance of the optical filter was examined, it had an absorption maximum at 585 nm, and the transmittance at the absorption maximum was 7%. Full width at half maximum of absorption maximum is 29 nm
Met. The change in the transmittance around 640 nm was steep, and the transmittance at 635 nm was 81%, about 30% at 645 nm, and about 13% at 650 nm. T ₂ is about 4
5%.

Comparative Example 3 An optical filter was prepared in exactly the same manner as in Example 4 except that the dye (e4) was not added to the visible filter layer.

Example 5 (Formation of undercoat layer) An undercoat layer was formed in the same manner as in Example 4.

(Formation of Hard Coat Layer Second Undercoat Layer) In the same manner as in Example 4, a hard coat layer second undercoat layer was formed.

(Coating of Hard Coat Layer) A hard coat layer was coated in the same manner as in Example 4. (Coating of Electromagnetic Wave and Infrared Shielding Layer and Antireflection Layer) In the same manner as in Example 4, an electromagnetic wave and infrared shielding layer and an antireflection layer were formed by sputtering.

(Formation of Second Undercoat Layer of Filter Layer) A second undercoat layer of the filter layer was formed in the same manner as in Example 4.

(Formation of visible and near-infrared filter layers)
Dye (b7) was added to 180 g of a 10% by weight aqueous solution of gelatin.
0.05 g, dye (a2) 0.15 g, dye (d2)
0.08 g and 0.05 g of dye (f2) are dissolved,
After stirring at 40 ° C. for 30 minutes, the mixture was filtered with a 2 μm polypropylene filter. The obtained coating solution for a filter layer was applied in the same manner as in Example 4.

When the spectral transmittance of the optical filter was examined, it had absorption maximums at 535 nm and 595 nm. The transmittance at the absorption maximum was 70% at 535 nm.
The absorption maximum at 595 nm was 18%. The half maximum width of the absorption maximum was 69 nm at 535 nm, and 29 nm at 595 nm. The change in transmittance around 440 nm is steep, and the transmittance at 445 nm is 78%.
It was about 24% at 435 nm and about 10% at 430 nm. T ₁ is about 31%.

Comparative Example 4 An optical filter was produced in exactly the same manner as in Example 5 except that the dye (d2) was not added to the visible filter layer. Example 6 (Formation of undercoat layer) An undercoat layer was formed in the same manner as in Example 4.

(Formation of Hard Coat Layer Second Undercoat Layer) In the same manner as in Example 4, a hard coat layer second undercoat layer was formed.

(Coating of Hard Coat Layer) A hard coat layer was coated in the same manner as in Example 4. (Coating of Electromagnetic Wave and Infrared Shielding Layer and Antireflection Layer) In the same manner as in Example 4, an electromagnetic wave and infrared shielding layer and an antireflection layer were formed by sputtering.

(Formation of Second Undercoat Layer of Filter Layer) A second undercoat layer of the filter layer was formed in the same manner as in Example 4.

(Formation of visible and near-infrared filter layers)
Dye (b7) was added to 180 g of a 10% by weight aqueous solution of gelatin.
0.05 g, dye (a2) 0.15 g, dye (c1)
0.10 g and 0.05 g of dye (f2) are dissolved,
After stirring at 40 ° C. for 30 minutes, the mixture was filtered with a 2 μm polypropylene filter. The obtained coating solution for a filter layer was applied in the same manner as in Example 4.

When the spectral transmittance of the above optical filter was examined, it had absorption maximums at 495 nm, 535 nm and 595 nm, and the transmittance at the absorption maximum was 65% at 495 nm and 70% at 535 nm. , 59
The absorption maximum at 5 nm was 18%. As for the half width of the absorption maximum, the absorption maximum at 535 nm was 38 nm, the absorption maximum at 535 nm was 69 nm, and the absorption maximum at 595 nm was 29 nm.

Comparative Example 5 An optical filter was produced in exactly the same manner as in Example 6, except that the dye (c1) was not added to the visible filter layer.

(Direct attachment to panel body) Various functional layers such as the antireflection layer and the filter layer prepared in Examples 4 to 6 and Comparative Examples 3 to 5 were applied to the filter layer surface of an optical filter provided on a polyethylene terephthalate film. An acrylic pressure-sensitive adhesive was applied to a thickness of 30 μm. Next, the front panel of the plasma display panel (PDS4202J-H, manufactured by Fujitsu Ltd.) was removed, and directly attached to the plasma display panel main body via an adhesive. (Evaluation of color of optical filter directly attached to panel) Example 4
6 and Comparative Examples 3 to 5, the color of the front surface of the plasma display to which the front plates were attached was measured with a spectroradiometer (SR-2A manufactured by Topcon Corporation). Table 2 below shows the measurement results and the visual evaluation results. Table 2 The optical filter produced in Comparative Example 3 was directly reddish, and the optical filter produced in Comparative Examples 4 and 5 was directly bluish, and the TV screen color was uncomfortable.

(Evaluation of Filter Function) The same evaluation was performed for the optical filters produced in Examples 4 to 6 and Comparative Examples 3 to 5. The electromagnetic wave and near-infrared shielding layer are connected to the metal ground on the back of the plasma display panel, and the electromagnetic wave radiated from the plasma display panel conducts the voltage induced in the electromagnetic wave and near-infrared shielding layer to the ground to evaluate the function. Carried out. As evaluation items, measurement of electromagnetic wave and infrared shielding ability, contrast of a displayed image, and evaluation of color reproducibility by visual observation were performed. The electromagnetic wave shielding ability was determined in Examples 4 to 6 and Comparative Example.
Frequency of 10MHz to 200M in any of 3 to 5
A minimum of 9 dB or more was obtained in the range of Hz, and the external leakage level of electromagnetic waves regulated by information processing devices and the like was achieved. The line spectrum shielding ability in the near infrared region is 8
It was about 9% at 00 nm and 4% or less at 850 nm, so that it was possible to prevent interference with infrared remote control devices installed in the vicinity. Contrast and visual color reproducibility were remarkably improved in all of Examples 4 to 6. The contrast was 6: 1 before the optical filter was directly attached with the front plate removed, but in each of the examples, the contrast was 12: 1. Before applying the optical filter directly, it was confirmed that red with orange was improved to pure red, greenish blue to bright blue, and yellowish white to pure white. In Comparative Examples 3 to 5, white was not improved as compared with Examples, such as white in Comparative Example 3 and bluish in Comparative Examples 4 and 5, depending on the direction of reflection of external light.

[0094]

[Brief description of the drawings]

FIG. 1 is a conceptual cross-sectional view when a front plate of the present invention is used on a front surface of a main body A of a cathode ray tube display (CRT) or a plasma display panel (PDP). FIG. 1A shows a case where the optical filter is directly attached to the main body A, and FIG. 1B shows a case where the front plate of the present invention is used on the front surface of the main body A and there is a space between the main body A and the front plate D. It is a conceptual diagram.

[Explanation of symbols]

A CRT or PDP B Support C Optical filter consisting of various filter layers and antireflection layer or a part thereof D Front plate

FIG. 2 is a schematic sectional view of a layer configuration of a front plate. Fig. 2 (a)
2 (b) is the same as FIG. 1 (a), FIG. 2 (c) and FIG.
Is an example of a layer configuration corresponding to the arrangement of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anti-reflection layer 2 Electromagnetic wave and infrared shielding layer 3 Hard coat layer 4 Plastic transparent support 5 Filter layer 6 Glass transparent support

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H048 CA04 CA12 CA13 CA15 CA19 CA23 CA25 CA27 CA29 2H091 FA01X FA37X FB02 FD06 FD24 GA17 LA03 LA12 LA13 5C058 AA11 BA35 DA01 DA15 5G435 AA04 AA17 BB06 CC12 DD12 GG11 HH07 KK11

Claims (10)

[Claims] 1. A transparent support having a visible filter layer on at least one side thereof, an optical filter having the visible filter layer provided on a front surface of an image display device, and an optical filter according to a method for measuring a reflective object described in JIS Z8722. An optical filter, characterized in that the color of the front surface of the provided image display device is measured and the color when illuminated with standard light D65 is in the range represented by the following formula (I). 0 ≦ | a * | ≦ 10, 0 ≦ | b * | ≦ 10 (I) Here, a * and b * represent a * and b * values in the CIE 1976 L * a * b * color space, and JIS Z It shall be displayed according to 8729. 2. The method according to claim 1, wherein the visible filter layer is 560 to 620.
2. An absorption maximum having a transmittance of 0.01 to 50% in a wavelength range of nm and an average transmittance of 70% or less in a wavelength range of 380 to 440 nm.
The optical filter as described. 3. The method according to claim 1, wherein the visible filter layer is 560 to 620.
2. An absorption maximum having a transmittance of 0.01 to 50% in a wavelength range of nm, and an average transmittance of 70% or less in a wavelength range of 640 to 780 nm.
The optical filter as described. 4. The method according to claim 1, wherein the visible filter layer has a thickness of 500 to 550.
In the wavelength range of nm, the absorption maximum has a transmittance of 20 to 85%, and in the wavelength range of 560 to 620 nm, the transmittance has a value of 0.0.
The optical filter according to claim 1, wherein the optical filter has an absorption maximum of 1 to 50%, and has an average transmittance of 70% or less in a wavelength range of 380 to 440 nm. 5. The method according to claim 1, wherein the visible filter layer is 500 to 550.
In the wavelength range of nm, the absorption maximum has a transmittance of 20 to 85%, and in the wavelength range of 560 to 620 nm, the transmittance has a value of 0.0.
The optical filter according to claim 1, wherein the optical filter has an absorption maximum of 1 to 50%, and has an average transmittance of 70% or less in a wavelength range of 640 to 780 nm. 6. The visible filter layer has a thickness of 460 to 500.
In both the wavelength range of 500 nm and 500 to 550 nm, the absorption maximum having a transmittance of 20 to 85% is 56
The transmittance is 0.01 to 5 in the wavelength range of 0 to 620 nm.
380 to 440 nm, each having 0% absorption maximum
2. The optical filter according to claim 1, wherein the average transmittance in the wavelength range is 70% or less. 7. The method according to claim 6, wherein the visible filter layer is 380 to 440.
2. The optical filter according to claim 1, wherein an average transmittance in a wavelength range of nm is 70% or less, and an average transmittance in a wavelength range of 640 to 780 nm is 70% or less. 8. An image display device using the optical filter according to claim 1. 9. A front panel of a plasma display panel using the optical filter according to claim 1. 10. The image display device according to claim 8, which is a plasma display panel.