JP2012194522A - Contrast-improving filter and image display device using filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contrast-improving filter which prevents deterioration in coloration of a contrast-improving layer or furthermore, in a light absorption function of a dye-containing light absorption layer achieved by pigment such as a near-infrared absorption function, due to ultraviolet exposure over time, and to provide an image display device using the same.SOLUTION: In a contrast-improving filter for a PDP, a contrast-improving layer having a light transmission part and a light absorption part is formed on a transparent base material which does not contain an ultraviolet absorbing agent, or furthermore, a dye-containing light absorption layer containing dye is formed. At least the light transmission part of the contrast-improving layer is made of a cured material of a resin composition containing a photopolymerizable compound, an ultraviolet absorbing agent, and a compound expressed by formula [1] as a photopolymerization initiator (in the formula, Ris an aromatic group, a methyl group, or hydrogen, and Rto Rare each independently a straight chain or branched chain alkyl group).

Description

  The present invention is a contrast enhancement filter that is disposed on the viewer side of a display panel such as a plasma display panel (also referred to as a PDP) to prevent the contrast of an image displayed on the display panel from being reduced by external light, and the filter. And an image display device using the. In particular, the present invention relates to a contrast enhancement filter excellent in light resistance against ultraviolet exposure over time, and an image display device using the same.

  On the viewer side of a display panel such as a plasma display panel (PDP), a contrast enhancement filter that prevents a decrease in image contrast due to external light, an electromagnetic wave shielding filter that shields electromagnetic waves emitted from the display panel, and a near infrared ray that shields near infrared rays Various filters such as an infrared absorption filter, a neon light absorption filter that blocks neon light, a color correction filter that adjusts a display image to a desired color tone, or an antireflection filter that prevents external light reflection are provided as required. .

  The contrast enhancement filter for PDP usually has at least a transparent substrate made of a resin film and a contrast enhancement layer. In the contrast improving layer, usually, a number of strip-shaped light absorbing portions are arranged in a stripe shape, and a space between the light absorbing portions is used as a light transmitting portion. External light is absorbed by the light absorption part, and image light is transmitted by the light transmission part. Such a contrast improving layer is formed by using a mold and a photocurable resin as a transparent resin layer having a large number of concave portions corresponding to the shape of the light absorbing portion on the surface of the transparent substrate, for example. Then, a light transmitting part is formed by photocuring by light irradiation such as ultraviolet rays, and then a dark ink containing carbon black in a resin binder is filled only in the inside of the concave part and solidified to form a large number of light absorbing parts. By forming. The neon light absorption filter is realized by a neon light absorption layer in which a neon light absorption dye is contained in a binder resin.

  In particular, in a filter for a display panel, it is desired to realize a plurality of filter functions with a single filter in terms of reducing the thickness of the filter and reducing costs by reducing material loss and the number of processes. For this reason, in the contrast enhancement filter, in addition to the contrast enhancement function, an electromagnetic wave shielding function, a near infrared absorption function, a neon light absorption function, a color correction function, an antireflection function, and the like are combined according to required performance. In many cases (Patent Document 1).

  Moreover, in filters other than the contrast enhancement filter, for example, the near infrared absorption filter is realized by a near infrared absorption layer in which a near infrared dye is contained in a binder resin. The neon light absorption filter and the color correction filter are also realized as a dye-containing light absorption layer in which a dye having an appropriate absorption wavelength is contained in a binder resin, like the near-infrared absorption filter.

  However, since the light transmission part of the contrast enhancement layer is made of a resin called a transparent resin layer, when the contrast enhancement filter is used, it may deteriorate over time and become colored (yellowish). The deterioration over time is due to ultraviolet rays or the like exposed in the use environment. Moreover, the near-infrared absorbing layer realized by the near-infrared absorbing dye is also deteriorated by exposure to ultraviolet rays over time. When the near-infrared absorbing layer is deteriorated, the near-infrared absorbing performance is lowered.

  Therefore, the present applicant, as an unpublished patent at the time of filing of the present invention, contained an ultraviolet absorber in a transparent substrate made of a resin film located on the viewer side of the contrast improving layer or near-infrared absorbing layer. A contrast enhancement filter having a configuration has been proposed (Patent Document 2).

JP 2008-146073 A Japanese Patent Application No. 2010-223958

  However, since the contrast enhancement filter according to Patent Document 2 uses a resin film containing an ultraviolet absorber as a transparent substrate, the material cost is higher than that of a general resin film not containing an ultraviolet absorber. There is a problem that the cost increases and the product cost increases.

  That is, the object of the present invention is to provide a contrast enhancement filter that does not deteriorate the light absorption function of the dye-containing light absorption layer realized by the coloring of the contrast enhancement layer or the dye such as the near-infrared absorption function due to ultraviolet exposure over time. Is to realize. Moreover, it is providing the image display apparatus using this filter.

（式中、Ｒ₁は芳香族基、メチル基、または水素を表わし、Ｒ₂〜Ｒ₇はそれぞれ独立して直鎖または分岐鎖状のアルキル基を表わす。） The contrast enhancement filter of the present invention includes a transparent base material that does not contain an ultraviolet absorber, a light absorbing portion that is formed on one surface of the transparent base material, and is arranged at intervals in the plane direction, and the light absorbing portion. A contrast enhancement filter having a light transmission part provided between at least parts, wherein the light transmission part includes a photopolymerizable compound, an ultraviolet absorber, and a photopolymerization initiator. It consists of a cured product formed by photopolymerizing a product, and the photopolymerization initiator is a compound represented by the following formula [1].

(In the formula, R ₁ represents an aromatic group, a methyl group, or hydrogen, and R _{2 to} R ₇ each independently represents a linear or branched alkyl group.)

In a preferred embodiment of the present invention, the compound represented by the above formula [1] is bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide represented by the following formula [2].

  In a preferred embodiment of the present invention, the resin composition further contains an antioxidant.

  In a preferred embodiment of the present invention, the light absorbing portion is formed from a cured product formed by photopolymerizing a dark resin composition containing a photopolymerizable compound, an ultraviolet absorber, a photopolymerization initiator, and a light absorbing colorant. The photopolymerization initiator in the dark resin composition is a compound represented by the above formula [1] or the above formula [2].

  In a preferred embodiment of the present invention, the dark resin composition further contains an antioxidant.

  In the preferable aspect of this invention, it further has a pigment | dye containing light absorption layer containing a pigment | dye.

  In a preferred embodiment of the present invention, the dye-containing light absorption layer is a layer that bears one or more functions selected from a near infrared absorption function, a neon light absorption function, and a color correction function.

  In the image display device of the present invention, the contrast enhancement filter is positioned on the viewer side of the display panel, and the contrast enhancement layer is positioned closer to the viewer than the pigment-containing light absorption layer in the embodiment including the pigment-containing light absorption layer. It is characterized by having an orientation.

(1) According to the contrast improving filter of the present invention, the contrast improving layer itself contains an ultraviolet absorber, so that the transparent substrate does not contain the ultraviolet absorber and the contrast improving layer is exposed to ultraviolet light over time. Coloration can be prevented. Moreover, since it is not necessary to contain an ultraviolet absorber in a transparent base material, it is not necessary to use the resin film containing the ultraviolet absorber which becomes expensive as a transparent base material, and it can implement | achieve at lower cost. In addition, since it is not necessary to add an ultraviolet absorbing layer containing an ultraviolet absorber separately, an increase in the number of steps and an increase in manufacturing costs associated with the increase in the ultraviolet absorbing layer do not occur, and a cost-effective contrast improving filter can be obtained. I can do it. (2) Furthermore, even if the functional layer includes a dye-containing light absorption layer such as a near infrared absorption function, a neon light absorption function, a color correction function, etc., these functions are influenced by ultraviolet rays by the ultraviolet absorber included in the contrast enhancement layer. It can be prevented from decreasing over time.

(3) According to the image display device of the present invention, the contrast improving layer can be prevented from being colored by exposure to ultraviolet rays over time, and a dye such as a near infrared absorption function, a neon light absorption function, and a color correction function is used. Even when a dye-containing light absorption layer is provided, the light absorption function due to these can be prevented from being deteriorated by ultraviolet rays over time. For this reason, it is possible to prevent deterioration of the quality of the display image over time.

Sectional drawing which illustrates one form of the contrast improvement filter by this invention. Sectional drawing which illustrates another form (with a functional layer) of the contrast improvement filter by this invention. 1 is a cross-sectional view illustrating one embodiment of an image display device according to the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are conceptual diagrams, and the scale relationships, aspect ratios, and the like of components may be exaggerated. In this specification, the “surface direction” is a direction parallel to the sheet surface of the contrast enhancement filter, in other words, a direction parallel to the front and back surfaces of the contrast enhancement layer. The “functional layer” is a layer that performs functions other than the near-infrared absorption function, the neon light absorption function, and the color correction function, and the dye-containing light absorption layer is not included in the functional layer.

A. Contrast enhancement filter:
First, referring to the cross-sectional view of FIG. 1, the contrast enhancement filter of the present invention will be described in an embodiment. The contrast enhancement filter 10 of the present invention in the form illustrated in FIG. 1 is formed on a transparent base material 1 that does not contain an ultraviolet absorber and one surface of the transparent base material 1 (in the case of FIG. 1, the surface below the drawing). A light transmitting portion 2a in which a plurality of grooves are arranged in the surface direction; and a contrast improving layer 2 having a light absorbing portion 2b formed in the grooves of the light transmitting portion 2a. Furthermore, in the form of the figure, it has also the pigment | dye containing light absorption layer 3 formed adjacent to the contrast improvement layer 2 and containing pigment | dyes, such as a near-infrared absorption pigment | dye, as a wavelength absorption function layer.

  The light transmission part 2a is composed of a cured product formed by photopolymerizing a resin composition containing at least an ultraviolet absorber, a photopolymerizable compound, and a specific photopolymerization initiator represented by the formula [1]. It is an optical element. However, since the light transmission part 2a is a cured product by photopolymerization, if an ultraviolet absorber is contained, the ultraviolet rays used for photopolymerization are absorbed by the ultraviolet absorber. For this reason, in the present invention, a specific photopolymerization initiator represented by the above formula [1] is used so that even if a part or all of the ultraviolet rays are absorbed by the ultraviolet absorber, it is photopolymerized into a cured product. Use.

  By setting it as such a structure, provision of the ultraviolet-absorbing function by a ultraviolet absorber and formation of the light transmissive part 2a as a hardened | cured material of a photopolymerizable compound can be made compatible. For this reason, the contrast improving layer 2 itself can be prevented from being deteriorated and colored by ultraviolet rays. Furthermore, as the photopolymerizable compound represented by the above formula [1], bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide represented by the above formula [2] can be preferably used.

  In addition, the contrast enhancement filter 10 of the exemplary embodiment illustrated in FIG. 1 is configured to include the dye-containing light absorption layer 3. Thus, in the form having the dye-containing light absorbing layer 3, when the contrast improving filter 10 is used, the contrast improving layer 2 is of course used as an ultraviolet protective layer for the dye-containing light absorbing layer 3. To do. That is, the contrast enhancement filter 10 is used with the contrast enhancement layer 2 side facing the viewer V side with respect to the dye-containing light absorption layer 3. By doing in this way, the near-infrared absorption layer, the neon light absorption layer, the color correction layer, etc. can be protected from ultraviolet rays as the dye-containing light absorption layer 3.

  In the form of FIG. 1, the dye-containing light absorbing layer 3 is formed in contact with the contrast improving layer 2, but at least the light transmitting portion 2 a of the contrast improving layer 2 is specified as a photopolymerization initiator. Since the compound of the formula [1] or the formula [2] is used, even if the residue of the photopolymerization initiator moves to the dye-containing light absorbing layer 3, the dye in the layer is not deteriorated.

  In the case of a configuration in which the dye-containing light absorption layer 3 containing a dye that deteriorates due to ultraviolet rays does not exist, the direction of the contrast enhancement filter 10 depends on the intended function of each layer that it has. For example, in the case of a configuration composed of the transparent substrate 1 and the contrast improving layer 2, the observer V side may be the contrast improving layer 2 side or the transparent substrate 1 side. However, if the transparent base material 1 side is used as in the latter case, the transparent base material 1 can serve as a protective layer.

  The light absorbing portions 2b are usually arranged in a regular interval with the shape of the plan view being a band shape and extending in parallel with each other. For example, in the contrast improving layer 2 illustrated in the cross-sectional view of FIG. 1, the light absorbing portion 2 b has a triangular cross-sectional shape, a straight line shape in plan view, and extends perpendicularly from the front to the back of the paper. Yes. Further, the light transmission part 2a exists between the light absorption parts 2b in the left-right direction of the drawing and also exists above the top of the triangle of the light absorption part 2b in the drawing.

  If the example of the shape and dimension of the light transmission part 2a and the light absorption part 2b is shown here, the light absorption part 2b is a columnar body of the cross-sectional shape of an isosceles triangle with a base of 20 μm and a height of 120 μm. A large number of light absorbing portions 2b are arranged in a fixed cycle with a plurality of extending directions of the columnar bodies parallel to the surface direction and spaced apart from each other. Therefore, the planar view shape of the light absorbing portion 2b is that in which straight lines are arranged in one direction at intervals. The arrangement period of the light absorbing portion 2b is 80 μm (the interval is 60 μm), and the thickness of the light transmitting portion 2a is 200 μm. In addition, this invention is not limited to the shape and dimension which were illustrated here.

  Hereinafter, each layer will be described in detail.

(Transparent substrate)
As the transparent substrate 1, a transparent substrate made of glass, resin or the like can be used. The resin of the transparent substrate 1 is, for example, a polyester resin such as polyethylene terephthalate, a polyolefin resin such as a cycloolefin polymer, a cellulose resin such as triacetyl cellulose, an acrylic resin, or a polycarbonate resin. These resins are used in the form of films, sheets, and plates. Note that “film”, “sheet”, and “plate” are generally roughly distinguished by thickness, but in the present invention, they are merely different in name and there is no particular distinction in meaning. In addition, the thickness of the transparent base material 1 is 12-500 micrometers in the case of a resin sheet, for example.

  The transparent substrate 1 may contain various known additives as necessary, such as improvement of physical properties. For example, antistatic agents and fillers. However, no ultraviolet absorber is contained.

[Contrast improvement layer]
The contrast enhancement layer 2 is a layer containing an ultraviolet absorber formed on at least one surface of the transparent substrate 1 that does not contain an ultraviolet absorber, and a large number of light absorption layers arranged at predetermined intervals in the plane direction. It consists of a part 2b and a light transmission part 2a containing an ultraviolet absorber present at least between the light absorption part 2b. The light absorbing portion 2b absorbs external light, and the light transmitting portion 2a between the light absorbing portions 2b secures image light transmission and contains a UV absorber, thereby suppressing the influence of external light. , Improve contrast and absorb ultraviolet rays.

  The thickness of the contrast enhancement layer 2 is equal to the thickness of the light transmission part 2a, and the thickness of the light transmission part 2a is usually equal to or greater than the thickness of the light absorption part 2b. Although the thickness of the light transmission part 2a is based also on a specification, it is about 50-300 micrometers, for example, Preferably it is about 50-250 micrometers.

（式中、Ｒ₁は芳香族基、メチル基、または水素を表わし、Ｒ₂〜Ｒ₇はそれぞれ独立して直鎖または分岐鎖状のアルキル基を表わす。） [Light transmission part]
The light transmission part 2a is formed as a cured product of the resin composition by photopolymerizing and curing a resin composition containing at least an ultraviolet absorber, a photopolymerizable compound, and a photopolymerization initiator. A transparent optical element having Moreover, in the light transmission part 2a, the specific compound represented by following formula [1] is used as a photoinitiator.

(In the formula, R ₁ represents an aromatic group, a methyl group, or hydrogen, and R _{2 to} R ₇ each independently represents a linear or branched alkyl group.)

As the specific compound represented by the above formula [1], specifically, a compound represented by the following formula [2], bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, is preferably used. be able to.

  The photopolymerizable compound is not particularly limited as long as it is a compound that can be cured by photopolymerization by irradiation with light such as ultraviolet rays or visible light in the presence of a photopolymerization initiator, and a known compound can be appropriately employed. . As such a photopolymerizable compound, one or more selected from the group of prepolymers (including oligomers) and monomers that can be cured by light irradiation are used. The photopolymerizable compound is used as a photopolymerizable resin composition obtained by mixing one or more selected from these prepolymers and monomers, a photopolymerization initiator, and an ultraviolet absorber.

  The addition amount of the photopolymerization initiator in the resin composition is preferably 1 to 5% by mass, more preferably 2 to 3% by mass with respect to the total amount of the photopolymerizable compound. If the addition amount of the photopolymerization initiator is less than 1% by mass, the photopolymerizable compound cannot be sufficiently photopolymerized, and curing may be insufficient. If it exceeds 5% by mass, the cost is high. There is a risk. Moreover, when forming in contact with a pigment | dye containing light absorption layer, it is unpreferable also at the point which promotes deterioration of the pigment | dye in this layer.

  As the prepolymer and monomer of the photopolymerizable compound, specifically, a compound having a radical polymerizable unsaturated group such as (meth) acryloyl group or (meth) acryloyloxy group in the molecule can be used. For example, the (meth) acryloyl group means an acryloyl group or a methacryloyl group. Moreover, the following (meth) acrylates are the meanings of an acrylate or a methacrylate similarly. In addition, the acrylate compound and the methacrylate compound are collectively referred to simply as an acrylate (compound) or an acrylate compound.

  Examples of prepolymers having radically polymerizable unsaturated groups include acrylate-based prepolymers such as polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, and triazine (meth) acrylate. Etc. can be used.

As an example of a monomer having a radical polymerizable unsaturated group, in the case of an acrylate monomer, as a monofunctional monomer, methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenoxyethyl (meth) acrylate, Acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, carboxypolycaprolactone (meth) acrylate, etc. System monomers and (meth) acrylamide. In addition, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate as polyfunctional monomers , Trifunctional monomers such as tripropylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate monostearate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide tri ( Meta
) Trifunctional monomers such as acrylate, polyfunctionality of 4 or more such as pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. There are monomers.

  A known compound can be used as the ultraviolet absorber. Examples of such UV absorbers include organic UV absorbers such as benzotriazole, benzophenone, salicylate, and benzoate, and inorganic UV absorbers.

  Examples of the benzotriazole ultraviolet absorber in the organic ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-butylphenyl) benzotriazole, 2 -(2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5' -Di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl- 5′-methylphenyl) -5-chlorobenzotriazole or 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) 5-chloro-benzotriazole.

  Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and 2,2′-dihydroxy. Examples include -4-methoxybenzophenone or 2,2′-dihydroxy-4,4′-dimethoxybenzophenone.

  Examples of salicylate ultraviolet absorbers include phenyl salicylate, pt-butylphenyl salicylate, and p-octylphenyl salicylate. Examples of benzoate ultraviolet absorbers include hexadecyl-2,5-t-butyl-4-hydroxybenzoate, or 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-. Examples thereof include hydroxybenzoate.

  Examples of inorganic ultraviolet absorbers include fine powders such as titanium oxide, zinc oxide, cerium oxide, iron oxide, and barium sulfate.

  The absorption wavelength of the ultraviolet absorbent is preferably over the entire wavelength range of 10 to 380 nm in the ultraviolet band. By containing an ultraviolet absorber in the contrast enhancement layer 2, the ultraviolet absorption performance as the contrast enhancement filter 10 can be set to a transmittance of 0.2% or less in the wavelength range of 10 to 380 nm. It becomes.

  0.1-10 mass% is preferable with respect to the polymeric compound whole quantity, and, as for the addition amount of a ultraviolet absorber, More preferably, it is 1-5 mass%. When the addition amount of the ultraviolet absorber exceeds 10% by mass, the photopolymerization may be inhibited, and when it is less than 0.1% by mass, the ultraviolet absorption effect may not be sufficiently obtained. However, in the present invention, since the ultraviolet absorber is contained in the contrast improving layer 2 which is thick and usually 50 μm or more, if it is contained in a thin layer in order to increase the ultraviolet absorption performance depending on the thickness. Compared to, the volume ratio can be reduced. For this reason, it is easy to balance the inhibition of photopolymerization and the ultraviolet absorption performance.

  In order to photopolymerize a resin composition containing an ultraviolet absorber, a photopolymerizable compound, and the specific photopolymerization initiator, ultraviolet rays or visible light may be irradiated. However, when light in the ultraviolet region is used when photopolymerizing the light transmitting portion 2a or further the light absorbing portion 2b, the ultraviolet light on the long wavelength side of the boundary wavelength 380 nm side with the visible light region is used with an ultraviolet absorber. May be left to the extent that it can contribute to photopolymerization without being completely absorbed. In addition, this is not the case when the photopolymerization is performed with light in the visible light region of 380 nm or more.

  In this respect, the photopolymerization initiator composed of the compound represented by the above formula [1] or [2] has a relatively wide absorption wavelength region and is sensitive to ultraviolet rays of less than 380 nm, and is also effective for visible light of 380 nm or more. Can also be photopolymerized. Photopolymerization is performed by irradiation with ultraviolet rays, visible rays, or ultraviolet rays and visible rays.

  It is preferable that the resin composition further contains an antioxidant. By including an antioxidant in the resin composition, the color change in the visible light region and the color change in the near infrared region can be further suppressed. That is, there is a possibility that acid is generated from the residue of the photopolymerization initiator or the residue of the photopolymerizable compound due to ultraviolet rays and temperature, and the dye in the dye-containing light absorption layer is oxidized by this acid, and the dye may be deteriorated. is there. On the other hand, when the antioxidant is contained in the resin composition, since the oxidation of the dye contained in the dye-containing light absorption layer can be suppressed by the antioxidant, the deterioration of the dye can be further suppressed. The color change in the visible light region and the color change in the near infrared region can be further suppressed.

  Examples of the antioxidant include phenol-based, amine-based, sulfur-based, and phosphorus-based antioxidants. Examples of phenolic antioxidants include 2,6-di-t-butyl-p-cresol (BHT), 2,2′-methylenebis (4-methyl-6-t-butylphenol), triethylene glycol-bis [3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], Pentaerythrityl tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenylpropionate), 3 , 5-di-t-butyl-4-hydroxybenzylphosphonate-diethyl ester and the like.

  Examples of amine-based antioxidants include octyl diphenylamine, Nn-butyl-p-aminophenol, N, N-diisopropyl-p-phenylenediamine, n-butylamine, triethylamine, diethylaminomethyl methacrylate and the like.

  Examples of sulfur-based antioxidants include dilauryl-3,3'-thiodipropionate (DLTDP) and distearyl 3,3'-thiodipropionate (DSTDP). Examples of phosphorus antioxidants include triphenyl phosphite (TTP) and triisodecyl phosphite (TDP).

  It is preferable that the addition amount of antioxidant is 0.1-2.0 mass% with respect to the photopolymerizable compound whole quantity. If the added amount of the antioxidant is less than 0.1% by mass, the effect of containing the antioxidant may not be sufficiently obtained. If the added amount exceeds 2.0% by mass, the antioxidant is added. This is because there is a possibility of bleeding out from the light transmitting portion 2a.

[Light absorption part]
The light absorbing portion 2b is an optical element that absorbs external light and can be formed of a light-absorbing dark material. As the dark material, either an organic material or an inorganic material may be used. As the organic material, a dark resin composition such as a paint (or ink) in which a light-absorbing color material is contained in a binder resin can be used.

  As the light-absorbing color material, a dark color material having a high light-absorbing property and exhibiting a dark color, that is, a chromatic or achromatic color with low brightness can be used. A representative example of the dark color is black, and an achromatic black color is preferable because it does not affect the color of the image display and the external light absorption is large. In addition, examples of low-lightness chromatic colors include brown, amber, rosy, and dark green. As the dark color material, a known color material, for example, black pigment such as carbon black or black iron oxide, black dye such as aniline black, or the like may be used. The dark color material may be dark resin particles obtained by coloring acrylic resin particles or the like with these dark color materials in a dark color. Further, a dark color material may be an achromatic color such as black or a chromatic dark color by mixing a plurality of kinds of chromatic color materials such as blue, yellow, and red, and mixing the colors. The addition amount of the light-absorbing color material can be, for example, 5 to 100% by mass with respect to the total amount of the binder resin.

  The binder resin may be a thermoplastic resin such as an acrylic resin, a polycarbonate resin, or a styrene resin, but is preferably a curable resin from the viewpoint of rapid solidification or the like, and light that is cured by ultraviolet rays or an electron beam. It is preferable to use a curable resin. As the photocurable resin, the photopolymerizable compounds listed in the light transmission part 2a can be used.

  Since the light absorbing portion 2b is dark, it has an appropriate ultraviolet absorbing property by itself. Therefore, the light absorbing portion 2b does not need to contain an ultraviolet absorber, but contains an ultraviolet absorber. In addition, when the photopolymerization compound is formed by adding a photopolymerization initiator to photopolymerization, the photopolymerization initiator includes the above formulas [1] to [2] as in the case of the light transmitting portion 2a. It is preferable to use a compound of However, in the case where the light absorbing portion 2b is formed in contact with the dye-containing light absorbing layer 3 by adding a photopolymerization initiator to a photopolymerizable compound and photopolymerizing without containing an ultraviolet absorber, photopolymerization is performed. As the initiator, it is preferable to use a compound of the above formula [1] or the above formula [2] in order to prevent deterioration of the dye in the dye-containing light absorbing layer 3. In this case, the addition amount of the photopolymerization initiator in the dark resin composition is preferably 1 to 5% by mass, more preferably 1 to 3% by mass with respect to the total amount of the binder resin and the light absorbing colorant. %. If the addition amount of the photopolymerization initiator is less than 1% by mass, the photopolymerizable compound cannot be sufficiently photopolymerized, and curing may be insufficient. If it exceeds 5% by mass, the cost is high. In addition, the neon light absorbing dye may be deteriorated.

  On the other hand, when the light absorbing portion 2b is not in contact with the dye-containing light absorbing layer 3 and no ultraviolet absorber is contained, a conventionally known compound may be used as the photopolymerization initiator. For example, acetophenone photopolymerization initiator, benzophenone photopolymerization initiator, and the like.

  The dark resin composition preferably further contains an antioxidant. As the antioxidant, the same antioxidant as that contained in the resin composition for forming a light transmitting portion described above can be used, and thus detailed description thereof is omitted here. The antioxidant contained in the dark resin composition has the same effect as the antioxidant contained in the resin composition for the light transmission part.

  The addition amount of the antioxidant is preferably 0.1 to 2.0% by mass with respect to the total amount of the binder resin and the light-absorbing color material. If the added amount of the antioxidant is less than 0.1% by mass, the effect of containing the antioxidant may not be obtained. If the added amount exceeds 2.0% by mass, the antioxidant absorbs light. This is because there is a possibility of bleeding out from the portion 2b.

[Method for forming contrast enhancement layer]
The method for forming the contrast improving layer 2 itself may be a conventionally known method. That is, the contrast enhancing layer 2 is formed by a so-called photopolymer method (also called 2P method), which is formed by photopolymerizing a photopolymerizable compound. In the photopolymer method, if a cylindrical mold is used, the transparent base material 1 can be continuously molded while being supplied as a continuous sheet, and this is a molding method with excellent productivity.

  For example, first, the light transmitting portion 2a having a groove corresponding to the light absorbing portion 2b by light curing by light irradiation such as ultraviolet rays on the mold and the photocurable resin on the transparent substrate 1 by the 2P method. Form. Next, only the groove is filled with dark ink of dark color material by a wiping method and solidified to form a light absorbing portion 2b, thereby forming the contrast improving layer 2.

(Dye-containing light absorbing layer)
The dye-containing light absorbing layer 3 is a kind of functional layer, and is a layer that contains a dye and absorbs light. Examples of the dye-containing light absorbing layer 3 include a near infrared absorbing layer containing a near infrared absorbing dye, a neon light absorbing layer containing a neon light absorbing dye, and a color correcting layer containing a color correcting dye. The near-infrared absorption function, neon light absorption function, and color correction function based on these functions can be achieved by a single dye-containing light absorption layer 3 having one or more functions by mixing corresponding dyes in the same layer. Is also possible. Moreover, it may be used also as another functional layer, for example, an adhesive layer.

  The dye-containing light absorption layer 3 is formed as a layer containing a dye that absorbs a wavelength region desired to be absorbed, but is typically formed as a layer containing the dye in a binder resin.

  Near-infrared absorbing dyes used in the near-infrared absorbing layer include organic dyes such as anthraquinone compounds, naphthoquinone compounds, phthalocyanine compounds, diimonium compounds, dithionyl complexes, indium tin oxide, titanium oxide, and cesium-containing tungsten oxides. 1 type, or 2 or more types of inorganic pigments, such as a thing, is used together. In the combined use, for example, the combined use of a phthalocyanine compound and a diimonium compound is particularly preferable in terms of transparency to visible light, light resistance, and the like.

  The neon light absorbing dye used in the neon light absorbing layer is a dye that absorbs neon light emitted from the PDP. The neon light absorbing dye preferably has a maximum absorption peak in the vicinity of 590 nm when the central wavelength of the neon light is 590 nm. Specific examples of the neon light absorbing dye include neon light absorbing dyes such as cyanine dyes, oxonol dyes, methine dyes, subphthalocyanine dyes, porphyrin dyes, and the like. These pigments are used alone or in combination of two or more.

  The color correction pigment used in the color correction layer is a pigment for correcting the display image by the contrast enhancement filter to a desired color tone (natural color or a color slightly deviated from the natural color). Examples of such color correction dyes include organic dyes and inorganic dyes, and specific examples include anthraquinone and naphthalene dyes. These pigments are used alone or in combination of two or more.

  As the binder resin containing the pigment, it is preferable to use thermoplastic resins such as acrylic resin, polyester resin, urethane resin, and styrene resin, and thermosetting resins such as urethane resin, epoxy resin, and acrylic resin. When the adhesive layer is also used, an acrylic resin-based or polyester resin-based adhesive can be used as the binder resin. In addition, when there exists a possibility of the pigment deterioration by a photoinitiator, you should avoid the photocurable resin containing a photoinitiator.

  Various known additives may be added to the dye-containing light absorbing layer as necessary. For example, ultraviolet absorbers, antistatic agents, fillers and the like.

[Other layers: Functional layers]
The contrast enhancement filter 10 according to the present invention may appropriately include other layers other than the above-described layers. For example, a functional layer. As the functional layer, various functional layers in a display front filter such as a conventionally known contrast enhancement filter can be appropriately employed. Such functional layers can be broadly classified into an optical functional layer responsible for optical functions and a non-optical functional layer responsible for functions other than optical functions. If the example of an optical function layer is given, there exists an antireflection layer (any one of antiglare, antireflection, antiglare, and antireflection) as layers other than the said pigment-containing light absorption layer.

  Examples of non-optical functional layers include an electromagnetic wave shielding layer that shields electromagnetic waves from the display panel, a surface protective layer and a hard coat layer that protect the surface, an antistatic layer, a pollution prevention layer, an impact resistant layer, and two layers. There are a barrier layer for preventing mass transfer and an adhesive layer (including a pressure-sensitive adhesive layer) that adheres the two layers. Each layer of the optical functional layer and the non-optical functional layer may be a single layer that also functions, or may be shared between the optical functional layer and the non-optical functional layer. The functional layer may also be used as the light transmission part 2a and the dye-containing light absorption layer 3 in the contrast enhancement layer 2.

  The functional layer includes the other surface of the transparent substrate 1 (the surface on which the contrast improving layer 2 is not formed), between the transparent substrate 1 and the contrast improving layer 2, and between the contrast improving layer 2 and the dye-containing light. It can be provided at any one or more positions between the absorption layer 3 and the surface of the dye-containing light absorption layer 3.

  For example, the contrast enhancement filter 10 illustrated in FIG. 2 is an example in which the functional layer 4 is provided on the other surface above the transparent substrate 1, and the functional layer 4 is positioned on the outermost surface on the viewer V side. And an antireflection layer, a protective layer, and the like.

  Further, the contrast improving filter 10 in the plasma display device 100 illustrated in FIG. 3 is a form in which the dye-containing light absorbing layer 3 also functions as an adhesive layer. Moreover, in the same figure, it is a form example which also has the functional layer 4 as an antireflection layer etc. in the other surface above the drawing of the transparent base material 1.

B. Image display device:
The image display device according to the present invention, like the image display device 100 shown in the embodiment of FIG. 3, has the above-described contrast enhancement filter 10 on the surface of the display panel 20 on the side of the viewer V, which absorbs dye-containing light. Since the layer 3 is included, the image display device has a configuration in which the contrast improving layer 2 is positioned more on the viewer V side than the dye-containing light absorbing layer 3.

  The display panel 20 may employ various known display panels such as a plasma display panel, a liquid crystal panel, and an EL (electroluminescence) panel.

  In addition to the display panel 20 and the contrast enhancement filter 10, the image display device 100 includes a display driving circuit, wiring for connecting the driving circuit and the display panel, a chassis or frame that integrates them into a panel module, Depending on the application of the display device, for example, in the case of a television receiver, various known components such as various input / output components such as a tuner, a casing (cabinet) for storing these components, and the like can be provided. These other components are not particularly limited, and depend on the application.

  By using such a configuration image display device 100, the effect based on the contrast enhancement filter 10 described above can be obtained. As a result, the contrast enhancement layer 2 or the dye-containing light absorption layer provided in the contrast enhancement filter 10 does not deteriorate with time due to ultraviolet rays, so that a display device with little deterioration in the quality of the display image with time is obtained.

C. Variations:
The contrast enhancement filter 10 and the image display device 100 using the same according to the present invention may include components other than those described above without departing from the gist of the present invention. Further, the above-described constituent elements may be modified other than the above.

  For example, the cross-sectional shape of the light absorbing portion 2b is a triangular shape having a straight line around the entire periphery in the embodiment illustrated in FIG. 1 and has a wedge shape, but may have other shapes. The cross-sectional shape may be a trapezoidal shape, a pentagonal shape, a hexagonal shape, or the like. Alternatively, both of the triangle and the trapezoid, or one of the hypotenuses may have a polygonal shape or a curved shape (a convex shape or a concave shape toward the outside of the light absorbing portion 2b).

  The transparent base material layer 1 side (upper side in FIG. 1) of the light absorbing portion 2b may be a shape that is rounded with a smooth continuous curve having no cusp in a convex shape toward the outside of the light absorbing portion 2b. In FIG. 1, the light absorbing portion 2b has an isosceles triangular wedge shape, and the direction of the wedge-shaped tip may be on the viewer V side as shown in FIG. 1, or vice versa. Moreover, although the direction of the contrast improvement layer 2 and the transparent base material 1 illustrated the transparent base material 1 side in the observer V side in FIG. 1, this may be reverse. Further, in FIG. 1 and the like, the light absorbing portion 2b is a columnar object in a stereoscopic view, and the extending direction is parallel to the surface direction, and a large number of the light absorbing portions 2b are arranged at intervals. It may be configured in a lattice shape in the direction.

  As described above, the viewing angle is adjusted by adjusting the traveling direction of the image light from the display panel by variously adjusting the cross-sectional shape of the light absorbing portion 2b and the shape relationship between the light absorbing portion 2b and the light transmitting portion 2a. Or the amount of light absorption with respect to various angle components of external light can be adjusted.

  Further, the contrast improving layer 2 can have a contrast improving effect, but it is also possible to emit image light with a viewing angle narrowed down to a specific direction such as the front direction. Also, it may have a function as a peep prevention filter.

D. Use:
The contrast enhancement filter according to the present invention is suitably used for applications arranged on the viewer side of a display panel in various image display devices. The display panel is, for example, a plasma display panel, a liquid crystal panel, an EL (electroluminescence) panel, or the like, and among them, the plasma display panel is one of suitable panels.

  Such an image display device according to the present invention is an image of a television receiver, measuring device or instrument, office device, medical device, computer device, telephone, electronic signboard, game device, digital photo frame, portable information terminal, etc. It is suitable as a display device.

  Hereinafter, the present invention will be described in detail with reference to examples and comparative examples.

Example 1
A contrast-enhancing filter 10 having a configuration as illustrated in FIG. 1 and having the dye-containing light absorbing layer 3 also serving as a pressure-sensitive adhesive layer as a functional layer was produced as follows.

<Preparation of resin composition for forming light transmitting portion>
Add 20 parts by mass of isophorone diisocyanate and 5 parts by mass of methoxypolyethylene glycol (Molecular weight 400, manufactured by Toho Chemical Industry Co., Ltd., trade name: Methoxy PEG400) to a flask equipped with a thermometer, a condenser, and a stirrer. While maintaining, 15 parts by mass of pentaerythritol triacrylate was dropped from the dropping funnel over 20 minutes. Thereafter, 15 parts by mass of pentaerythritol triacrylate and 0.0002 parts by mass of tin octylate as a catalyst were added, the temperature was raised to 80 ° C., the temperature was kept for 2 hours, and the urethanization reaction was continued to obtain urethane acrylate A.

  And it represents with said Formula [2] as a photoinitiator in the acrylate type photopolymerizable compound mixture which mixed 50 mass parts of this urethane acrylate A and dimethylol tricyclodecane diacrylate as a polyfunctional acrylate monomer. 2.0 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure (registered trademark) 819, manufactured by BASF), and benzotriazole-based ultraviolet absorber (TINUVIN (registered) (Trademark) 109, manufactured by BASF) 0.5 parts by mass was mixed and homogenized to prepare a resin composition for forming a light transmission part.

<Preparation of dark resin composition for forming light absorbing portion>
84 parts by mass of the same acrylate-based photopolymerizable compound mixture as the resin composition for forming the light transmission part, and carbon cross-linked acrylic fine particles having an average particle diameter of 4.0 μm (Gantz Kasei Co., Ltd.) 16 parts by mass, and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide represented by the formula [2] as a photopolymerization initiator (Irgacure (registered trademark) 819, manufactured by BASF) 3.0 Mixing and homogenizing 0.5 parts by mass of benzotriazole-based UV absorber (TINUVIN (registered trademark) 109, manufactured by BASF) as a UV absorber, a dark resin composition for forming a light absorber is obtained. It was adjusted.

<Formation of contrast enhancement layer>
As transparent substrate 1, a biaxially stretched polyethylene terephthalate film (product number A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm is continuously molded with a molding die using a resin composition for forming a light transmission part. While processing, and irradiating ultraviolet rays (and visible light) with an ultraviolet ray source (Fusion UV Systems Japan Co., Ltd., D bulb, output around 350 nm to 450 nm strong) to form a light transmission part A large number of wedge-shaped grooves were formed in parallel on the surface of the light transmission portion with a space therebetween.

  Next, after filling the wedge-shaped groove with the dark resin composition for forming the light absorbing portion obtained above and scraping off the excess dark resin composition with a metal doctor blade, the same ultraviolet light source ( The dark resin composition was cured by irradiating ultraviolet rays (and visible light) with a D bulb) to form the light absorbing portion 2b, and the contrast improving layer 2 was obtained.

<Formation of dye-containing light absorption layer>
Acrylic pressure-sensitive adhesive (pressure-sensitive pressure-sensitive adhesive “Olivein (registered trademark)” BPS6271: trade name, solid content 27%, manufactured by Toyo Ink Mfg. Co., Ltd. 99.7 parts by mass, and curing agent (BXX5627: trade name, Toyo Ink) Manufactured by Seisakusho Co., Ltd.) 0.3 parts by mass, as near-infrared absorbing dye, 0.05 parts by mass of phthalocyanine compound (IR12: trade name, manufactured by Nippon Shokubai Co., Ltd.), phthalocyanine compound (IR14: trade name, Inc.) 0.02 part by mass of Nippon Shokubai Co., Ltd. and 0.03 part by mass of diimmonium compound (IRG-068: trade name, manufactured by Nippon Shokubai Co., Ltd.) were blended. Furthermore, 0.01 part by weight of neon light absorbing dye (TAP2: trade name, manufactured by Yamada Chemical Co., Ltd.) was blended. Furthermore, 4 parts by mass of Cyasorb (registered trademark) UV24 (manufactured by Cytec) as an ultraviolet absorber, 2 parts by mass of TINUVIN (registered trademark) 144 (manufactured by BASF) as a light stabilizer, KAYASET as a toning dye 0.1 parts by mass (manufactured by Nippon Kayaku Co., Ltd.) and 0.05 parts by mass of Kunipia (registered trademark) D36 (manufactured by Kunimine Kogyo Co., Ltd.) as a layered clay mineral were blended to obtain a mixture. The mixture was sufficiently stirred to prepare a resin composition for forming a dye-containing light absorption layer.

  After applying this resin composition to a thickness of 25 μm on a 38 μm thick peelable release film (Toyobo Co., Ltd., E7007) and drying at 100 ° C. for 2 minutes to form a coating film, A 38 μm light-release mold release film (E7005, manufactured by Toyobo Co., Ltd.) was laminated on this coating film to prepare an optical filter layer having adhesiveness provided between the release films.

<Production of contrast enhancement filter>
The light peelable release film of the optical filter layer was peeled off and bonded to the surface of the contrast enhancement layer 2 to produce a target contrast enhancement filter.

<< Comparative Example 1 >>
In Example 1, in the resin composition for forming the light transmission part and the dark resin composition for forming the light absorption part, the photopolymerization initiator is represented by 1-bidoxy-cyclohexyl-phenyl represented by the following formula [3]. -Changed to ketone (Irgacure (registered trademark) 184, manufactured by BASF) (2.0 parts by mass for the resin composition for forming the light transmission part, 5.0 parts by mass for the dark color resin composition for forming the light absorption part) Except for this, an attempt was made to produce a contrast enhancement filter in the same manner as in Example 1. However, due to the influence of the contained ultraviolet absorber, the photopolymerization was incomplete and the cured contrast enhancement layer 2 could not be obtained. For this reason, lamination | stacking of the pigment | dye containing light absorption layer after this was not performed.

<Performance evaluation>
Using the contrast enhancement filter of Example 1, the durability of the dye-containing light absorbing layer was evaluated. The evaluation was performed by a light resistance test. The near-infrared absorption function and the neon light absorption function before and after the test were examined by the amount of change in transmittance, and the color correction function was examined by the degree of change in color of the transmission chromaticity of the filter. .

<Light resistance test>
The light resistance test was performed using a light resistance tester (Atlas Suntest XLS +, manufactured by Tokyo Seiki Seisakusho Co., Ltd.). Specifically, a xenon lamp with an output of 550 W / m ² was applied to the contrast enhancement filter and left in an environment of 63 ° C. for 140 hours.

<Spectroscopic evaluation and transmission chromaticity evaluation>
The transmittance before and after the test was measured using a spectrophotometer (product name: UV2200, manufactured by Shimadzu Corporation), and the near-infrared absorption function is a change in transmittance at a wavelength of 900 nm as a representative wavelength of the near-infrared absorption band. It was evaluated with. The neon light absorption function was evaluated by the change in transmittance at a wavelength of 592 nm, which is the approximate center wavelength of the neon light absorption band. Note that the amount of change in transmittance before and after the test was determined by the following equation.
Change in transmittance = transmittance after test (%)-transmittance before test (%)

  In addition, the transmission chromaticity after the test is measured using the spectrophotometer, and changes in Δx and Δy in the transmission chromaticity (Δx, Δy) in accordance with JIS Z8701 are also measured as color changes. Calculated.

The results are shown in Table 1.

  As shown in Table 1, even after the light resistance test, in Example 1, the near-infrared absorption performance is such that the transmittance at a wavelength of 900 nm is increased by 0.7%, and the neon light absorption performance is at a wavelength of 592 nm. The transmittance only increased by 2.8%.

  In addition, the amount of change in both the color change of Δx and Δy is in the range of 0.005 or less in Example 1, which is preferable from the viewpoint of small color change even after long-term use.

Example 2
In Example 2, an attempt was made to produce a contrast enhancement filter by the same method as in Example 1 except that the resin composition for forming a light transmission part in Example 1 was replaced with the following resin composition.

<Preparation of resin composition for forming light transmitting portion>
In Example 2, 100 parts by mass of an acrylate-based photopolymerizable compound mixture composed of urethane acrylate and dimethylol tricyclodecane diacrylate prepared in Example 1 is represented by the formula [2] as a photopolymerization initiator. 3.0 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure (registered trademark) 819, manufactured by BASF), as a UV absorber, a benzotriazole-based UV absorber (TINUVIN (registered trademark)) 109, manufactured by BASF) and 0.5 parts by mass of pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (Irganox (registered trademark)) as an antioxidant 1010, manufactured by BASF Corp.) 1.0 parts by weight is mixed and homogenized to form a light transmission part To prepare a resin composition.

Example 3
In Example 3, an attempt was made to produce a contrast-enhancing filter by the same method as in Example 1 except that the resin composition for forming a light transmission part in Example 1 was replaced with the following resin composition.

<Preparation of resin composition for forming light transmitting portion>
In Example 3, 100 parts by mass of the acrylate-based photopolymerizable compound mixture composed of urethane acrylate and dimethyloltricyclodecane diacrylate prepared in Example 1 is represented by the formula [2] as a photopolymerization initiator. 3.0 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure (registered trademark) 819, manufactured by BASF), and benzotriazole ultraviolet absorber (TINUVIN (registered trademark) as an ultraviolet absorber) 109, manufactured by BASF) 0.5 parts by mass was mixed and homogenized to prepare a resin composition for forming a light transmission part.

Example 4
In Example 4, an attempt was made to produce a contrast enhancement filter by the same method as in Example 1 except that the resin composition for forming a light transmission part in Example 1 was replaced with the following resin composition.

<Preparation of resin composition for forming light transmitting portion>
In Example 4, 100 parts by mass of an acrylate-based photopolymerizable compound mixture composed of urethane acrylate and dimethyloltricyclodecane diacrylate prepared in Example 1 is represented by the above formula [2] as a photopolymerization initiator. 3.0 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure (registered trademark) 819, manufactured by BASF), as a UV absorber, a benzotriazole-based UV absorber (TINUVIN (registered trademark)) 109, manufactured by BASF), and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (Irganox (registered trademark)) as an antioxidant. 1010, manufactured by BASF Corp.) 1.0 parts by weight is mixed and homogenized to form a light transmission part To prepare a resin composition.

Example 5
In Example 5, an attempt was made to produce a contrast improving filter by the same method as in Example 1 except that the resin composition for forming a light transmission part in Example 1 was replaced with the following resin composition.

<Preparation of resin composition for forming light transmitting portion>
In Example 5, 100 parts by mass of the acrylate-based photopolymerizable compound mixture composed of urethane acrylate and dimethyloltricyclodecane diacrylate prepared in Example 1 is represented by the formula [2] as a photopolymerization initiator. 3.0 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure (registered trademark) 819, manufactured by BASF), and benzotriazole ultraviolet absorber (TINUVIN (registered trademark) as an ultraviolet absorber) 109, manufactured by BASF) 1.0 parts by mass were mixed and homogenized to prepare a resin composition for forming a light transmission part.

<Performance evaluation>
Using the contrast enhancing filters of Examples 2 to 5, the durability of the dye-containing light absorbing layer was evaluated. The evaluation was performed by a light resistance test. And it investigated by the change degree of the color of the transmission chromaticity of the filter before the test start and after the test.

<Light resistance test>
The light resistance test was performed using a light resistance tester (Ci4000, manufactured by Atlas Material Testing Technology LLC). Specifically, a xenon lamp with an output of 550 W / m ² was applied to the contrast enhancement filter and left in an environment of 63 ° C. for 140 hours.

<Transmission chromaticity evaluation>
Measure the transmission chromaticity before and after the test using the spectrophotometer described above, and calculate the change in Δx and Δy in the transmission chromaticity (Δx, Δy) according to JIS Z8701 as the color change. did.

The results are shown in Table 2.

  As shown in Table 2, the contrast-enhancing filters of Examples 2 and 4 to which the antioxidant was added were compared with the contrast-enhancing filters of Examples 3 and 5 to which no antioxidant was added, and Δx and Δy Both were small. From this result, it was confirmed that the color change can be further suppressed by adding an antioxidant.

DESCRIPTION OF SYMBOLS 1 Transparent base material 2 Contrast improvement layer 2a Light absorption part 2b Light transmission part 3 Dye containing light absorption layer (wavelength absorption functional layer)
4 functional layer 10 contrast enhancement filter 20 display panel 100 image display device V observer

Claims (9)

A transparent base material that does not contain an ultraviolet absorber, a light absorption part that is formed on one surface of the transparent base material and that is arranged in a large number at intervals in the plane direction, and provided between at least the light absorption part A contrast enhancement filter having a light enhancement part, and a contrast enhancement layer,
The light transmission part is made of a cured product formed by photopolymerizing a resin composition containing a photopolymerizable compound, an ultraviolet absorber and a photopolymerization initiator, and the photopolymerization initiator is represented by the following formula [1]. Contrast enhancement filter, which is a compound

(In the formula, R ₁ represents an aromatic group, a methyl group, or hydrogen, and R _{2 to} R ₇ each independently represents a linear or branched alkyl group.) The contrast enhancement filter according to claim 1, wherein the compound represented by the formula [1] is bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide represented by the following formula [2].

  The contrast enhancement filter according to claim 1, wherein the resin composition further contains an antioxidant.   The light absorbing portion is made of a cured product formed by photopolymerizing a dark resin composition containing a photopolymerizable compound, an ultraviolet absorber, a photopolymerization initiator, and a light-absorbing colorant, and the dark resin composition The contrast improvement filter according to any one of claims 1 to 3, wherein the photopolymerization initiator is a compound represented by the formula [1] or the formula [2].   The contrast enhancement filter according to claim 4, wherein the dark resin composition further comprises an antioxidant.   Furthermore, the contrast improvement filter as described in any one of Claim 1 thru | or 5 which has a pigment | dye containing light absorption layer containing a pigment | dye.   The contrast enhancement filter according to claim 6, wherein the dye-containing light absorption layer is a layer having one or more functions selected from a near infrared absorption function, a neon light absorption function, and a color correction function.   An image display device comprising the contrast enhancement filter according to any one of claims 1 to 5 on an observer side of a display panel.   An image display device comprising the contrast enhancement filter according to claim 6 or 7 in a direction in which the contrast enhancement layer is positioned closer to the viewer than the dye-containing light absorption layer.

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