JP2010145787A - Color filter substrate and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter substrate and a liquid crystal display device, having green pixels free from degradation in visibility when the screen is viewed in an oblique direction, in liquid crystal display devices of various display systems even when a high lightness of green pixels is achieved by using PG58 pigment. <P>SOLUTION: The color filter substrate is provided with green pixels formed by using the following photocurable green color composition and having a retardation value (R<SB>th</SB>) in the thickness direction ranging from -21.3 nm to 25.6 nm. The composition contains at least, as essential components: a pigment containing C.I.Pigment Green 58, a melamine compound, C.I.Pigment Green 36 and C.I.Pigment Yellow 138; a transparent resin; a photopolymerizable monomer; and a solvent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention provides a color filter substrate and a liquid crystal display device in which the retardation value (R _th ) in the thickness direction of a green pixel of the color filter is controlled in order to improve the visibility when the liquid crystal display device is observed from an oblique direction. About providing.

  In recent years, a high viewing angle has been realized in a liquid crystal display device adopting a VA (Vertical Alignment) display method, an IPS (In-Plane Switching) display method, and the like. However, there still remains a problem that the viewing angle dependency occurs such that the hue and contrast are lower than those in the front direction. The reason why this viewing angle dependency occurs is that light leakage occurs in a black display state in an oblique direction, and improvement of this light leakage is demanded.

One of the causes of the above-mentioned light leakage is that the linearly polarized light incident on the liquid crystal layer is changed to elliptically polarized light by shifting the phase due to the birefringence of the liquid crystal molecules themselves, and thereby the exit side polarizing film This is because the emitted light cannot be completely shielded at. As a countermeasure, a retardation film is provided to return elliptically polarized light to linearly polarized light. However, complete retardation is not compensated for the oblique direction, and it is not possible to meet the demand for light leakage improvement. Currently. For this reason, it is necessary to control the phase difference in the color filter in order to improve light leakage in an oblique direction, in other words, to improve the viewing angle dependency (Patent Document 1). The phase difference control required for the color filter is to adjust the thickness direction retardation value (R _th ) to a desired value.

At this time, R _th required for the color filter is a liquid crystal display method (IPS display method, VA display method, etc.), a member constituting the liquid crystal display device (polarizing film, retardation film, etc.), or a cell in the liquid crystal cell. different value determined by the difference of the gap, in order for these composition and structure corresponding to a different liquid crystal display device, it is desirable to be able to control the color filter substrate R _th in a wide range. As the value of _Rth obtained at this time, a value of 0 or more is obtained in the VA display method, and a value near 0 is obtained in the IPS display method. However, as described above, the required _Rth differs depending on the members constituting the liquid crystal display device. Therefore, in order to cope with this, it is necessary to control _Rth in a wide range in the color filter substrate.

  As a means for controlling the phase difference of the color filter, a method of adding a phase difference adjusting agent such as a liquid crystal compound to the coloring composition constituting the color filter, or a method of separately providing a phase difference control layer on the pixel of the color filter Has been proposed. However, there is a problem that the cost of the color filter is increased because the material cost and the manufacturing cost are increased, and the development of a technique capable of controlling the phase difference without greatly changing the configuration and structure is desired.

At this time, there is a method for controlling _Rth by adding a thermosetting resin having a melamine skeleton to the coloring composition as a means / method for controlling _Rth without imposing a large burden on materials and production costs. (Patent Document 2). However, in order to deal with liquid crystal display devices having different configurations and structures as described above, it is necessary to be able to control _Rth in a wide range in the color filter, and it is necessary to establish a control method. Incidentally, there is a method of controlling the film thickness by changing R _th of a pixel provided in the color filter substrate, since the change hue aimed When thus changing the pixel thickness, Rth in thickness Since it is difficult to control _Rth , it is necessary to control _Rth with a coloring composition forming a pixel.

  As another very important problem, liquid crystal display devices are required to have low power consumption. For this reason, color filters need to be further improved in brightness. In response to the demand for higher brightness, organic pigments contained in green pixels of color filters have been widely used until now. I. Pigment Green 36 (hereinafter referred to as PG36), C.I. I. The brightness is improved by changing to Pigment Green 58 (hereinafter referred to as PG58).

However, in the green pixel using only PG58 having a high brightness as an organic pigment, since the range capable of controlling the R _th is within 3nm about a narrow range of -1 nm, obliquely with respect to composition and structure is different liquid crystal display device since in order to improve the visibility drop of observing a screen from the direction it is necessary to control a wide range of R _th, it is necessary to establish a method of controlling the _Rth by adding the phase difference adjusting agent is there.
JP 2007-279379 A JP 2007-021897 A

  Therefore, the present invention provides a liquid crystal display device of a different display method, in which a green pixel that does not cause a decrease in visibility when the screen is viewed from an oblique direction even when a high brightness of the green pixel is realized using the PG58 pigment. It is an object of the present invention to provide a color filter substrate and a liquid crystal display device.

In order to achieve the above object, the present invention provides at least C.I. I. Pigment Green 58, melamine compound, C.I. I. Pigment Green 36, C.I. I. A retardation value (R _th ) in the thickness direction formed using a pigment containing transparent pigment 138, a transparent resin, a photopolymerizable monomer, and a photocurable green coloring composition mainly containing a solvent is -21. A color filter substrate having a green pixel in a range of .3 nm to 25.6 nm.

  The background of the combination of the pigments according to the present invention will be described below.

First, R _th of a green pixel containing only PG58 was confirmed. As a result, it was found that R _th is slightly different depending on other compositions forming the green pixel, but R _th is in a narrow range of about −1 nm to 3 nm when the pixel film thickness is 1 to 4 μm. However, it is necessary to control _Rth in a wide range in order to improve the visibility reduction when observing a screen from an oblique direction with respect to liquid crystal display devices having different configurations and structures, and from the viewpoint of cost. Since it is necessary to search for a material that can increase or decrease _Rth without greatly changing the configuration of the color filter, pigment screening was performed.

In this case, for materials that can reduce the R _th, the result of searching that is widely used in forming the green pixel on the condition, it found that PG36 is valid. The addition of this time PG36 green coloring composition containing the PG58, -16.2nm whereas in addition to non-pixel R _th was 1.9nm, the R _th in the green pixel added from 1.9nm It was found that it can be reduced. It was further found that the controllable within a range of the R _th from 1.9nm to -16.2nm by adjusting the addition amount.

Besides, PY138 is effective as a material to reduce the R _th, when added to a green coloring composition containing the PG58 and PY138, it found that can reduce the R _th from 1.9nm to -9.1Nm. Further, by adjusting the addition amount, R _th is reduced from 1.9 nm to −
It was found that control was possible within a range up to 9.1 nm.

Furthermore, when added to a green coloring composition containing the PG58 both PG36 and PY138, found that R _th can be reduced from 1.9nm to -21.3Nm. It was further found that the controllable within a range of the R _th from 1.9nm to -21.3nm by adjusting both the amount added.

As a material capable of increasing the R _th Conversely, a compound having a melamine skeleton (melamine compound) is effective, in the green pixel formed by adding melamine compound green coloring composition containing the PG58, R It has been found that _th can be increased up to 25.6 nm. Also found to be able to control within a range of the R _th from 1.9nm to 25.6nm by adjusting the addition amount. The details of the melamine resin used in the present invention will be described later.

From the above, the green coloring composition containing at least PG58 as organic pigments, PG 36, PY138, by forming a green color pixel containing one or more of any of the melamine compound, the R _th from -21.3nm It was found that control was possible within the range of 25.6 nm.

The present invention, a wide range R _th of positive or negative green pixel also be used PG58 pigment high lightness, it was possible to identify the pigment to be combined with PG58 pigment which can be controlled to a desired value. Therefore, even a liquid crystal display device with a different display method can be easily adjusted to a desired R _th corresponding to the optical characteristics of the display device. A liquid crystal display device with low power consumption can be provided.

  Hereinafter, embodiments of the present invention will be described.

The thickness direction retardation value of the green colored pixel can be determined using a three-dimensional refractive index measured using a phase difference measuring device such as a spectroscopic ellipsometer.
That is, phase difference measurement is performed with light having a wavelength of 550 nm from at least two directions of the front of the green pixel and an incident angle of 45 degrees, and a three-dimensional refractive index of Nx, Ny, and Nz is obtained. A phase difference value (R _th ) is calculated.
R _th = {(Nx + Ny) / 2−Nz} × d
In the formula, Nx is a refractive index in the x direction in the plane of the colored pixel layer, Ny is a refractive index in the y direction in the plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. D is the film thickness (nm) of the colored pixel layer.

  The color filter coloring composition used in the present invention is a liquid coating liquid in which an organic pigment is dispersed in at least an organic solvent, a photopolymerizable initiator, or a curing agent based on a polymer or monomer such as an acrylic resin or a cardo resin. . The colored composition can be used as a color resist used in photolithography or as ink for ink jet or printing. In addition, the detail of the composition as a coloring composition used for a color filter is mentioned later.

  As a melamine compound used for this invention, the commercially available thing represented with the following general formula (I) can be used, and a melamine compound is illustrated below.

  In the formula, R1, R2, and R3 are a hydrogen atom, a methylol group, an alkoxymethyl group, an alkoxy n-butyl group, and R4, R5, and R6 are a methylol group, an alkoxymethyl group, and an alkoxy n-butyl group, respectively. A copolymer combining two or more kinds of repeating units may be used. Two or more homopolymers or copolymers may be used in combination. In addition to the above, compounds having a 1,3,5-triazine ring, for example, those described in JP-A No. 2001-166144 can be used. Further, compounds represented by the following general formula (II) are also preferably used.

  R7 to R14 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and particularly preferably a hydrogen atom.

  Next, the color filter of the present invention will be described.

As shown in FIG. 1, the color filter of the present invention comprises a black matrix 2 which is a light shielding layer on a glass substrate 1, and at least 3 of red 3 (R), green 3 (G) and blue 3 (B). Colored pixels 3 are provided.
The color filter is not limited to these three colors, and may be a combination of complementary colors, or may be a multi-color filter of three or more colors including complementary colors and other colors.

  For example, C.I. I. Pigment Red 7, 14, 41, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 81: 4, 146, 168, 177, 178, 179, 184, 185, Red pigments such as 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, and 279 can be used, and a yellow pigment and an orange pigment can also be used in combination.

  Examples of the yellow pigment include C.I. used in the present invention. I. Pigment Yellow 138 and C.I. I. In addition to Pigment Yellow 150, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 147, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 187 188,193,194,199,198,213,214, and the like.

  Examples of the orange pigment include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

  The amount used is 10 to 90% by weight of the diketopyrrolopyrrole red pigment and 5 to 70% by weight of the anthraquinone red pigment based on the total weight of the pigment. From the viewpoint of contrast and the like, in particular, when focusing on the contrast, it is more preferable that the diketopyrrolopyrrole red pigment is 25 to 75% by weight and the anthraquinone red pigment is 30 to 60% by weight.

The red pixel can contain a yellow pigment or an orange pigment for the purpose of adjusting the hue, but it is preferable to use an azo metal complex-based yellow pigment from the viewpoint of high contrast. The amount used is preferably 5 to 25% by weight based on the total weight of the pigment, and if it is less than 5% by weight, hue adjustment such as sufficient brightness improvement cannot be achieved, and the amount exceeds 30% by weight. In this case, since the hue is shifted too yellow, the color reproducibility is deteriorated.

  In the above, examples of the diketopyrrolopyrrole red pigment include C.I. I. Pigment Red 254 and an anthraquinone red pigment include C.I. I. Pigment Red 177, an azo metal complex yellow pigment such as C.I. I. Pigment Yellow 150 and a quinophthalone yellow pigment, PY138 is preferable from the viewpoint of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  The green pixel includes C.I. used in the present invention. I. In addition to Pigment Green 58 and 36, for example, C.I. I. Pigment Green 10, 37 or the like can be used, and a yellow pigment can be used in combination. As the yellow pigment, the same pigments as those described in the description of the red pixel can be used.

  The amount used is 1 to 90% by weight of the green pigment, 1 to 60% by weight of the azo yellow pigment, and 1 to 60% by weight of the quinophthalone yellow pigment, including PG58, based on the total weight of the pigment. Is preferable from the viewpoint of pixel hue, brightness, film thickness, and the like.

  In the above, examples of the green pigment include C.I. I. Pigment Green 36 and 58, and azo yellow pigments include C.I. I. Pigment Yellow 150 and quinophthalone yellow pigments include C.I. I. Pigment Yellow 138 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  Examples of blue pixels include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, and the like, and a purple pigment can also be used in combination. Examples of purple pigments include C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like.

  The amount used is 40 to 100% by weight of the metal phthalocyanine blue pigment and 1 to 50% by weight of the dioxazine violet pigment based on the total weight of the pigment. It is preferable from a point, Furthermore, it is more preferable to make a metal phthalocyanine blue pigment 50 to 98 weight% and a dioxazine purple pigment 2 to 25 weight%.

  In the above, examples of the metal phthalocyanine blue pigment include C.I. I. Pigment Blue 15: 6, and dioxazine-based purple pigments include C.I. I. Pigment Violet 23 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

Inorganic pigments include yellow lead, zinc yellow, red bean (red iron (III) oxide), cadmium red, ultramarine blue, bitumen, chromium oxide green, cobalt green and other metal oxide powders, metal sulfide powders, metal powders Etc.
Inorganic pigments are used in combination with organic pigments in order to ensure good coatability, sensitivity, developability and the like while maintaining a balance between saturation and lightness. Furthermore, for color matching, a dye can be contained within a range that does not lower the heat resistance.

  Below, the coloring composition used in order to form each color pixel of the color filter of this invention is demonstrated.

  The pigment carrier contained in the coloring composition used for forming each color pixel is for dispersing the pigment, and is composed of a transparent resin, a precursor thereof, or a mixture thereof.

The transparent resin is a resin having a transmittance of preferably 80% or more, more preferably 95% or more in the entire wavelength region of 400 to 700 nm in the visible light region.
The transparent resin includes a thermoplastic resin, a thermosetting resin, and a photosensitive resin, and its precursor includes a monomer or an oligomer that is cured by irradiation with radiation to form a transparent resin. Alternatively, two or more kinds can be mixed and used.

The pigment carrier can be used in an amount of 30 to 700 parts by weight, preferably 60 to 450 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.
When a mixture of a transparent resin and its precursor is used as a pigment carrier, the transparent resin is 20 to 400 parts by weight, preferably 50 to 250 parts by weight, based on 100 parts by weight of the pigment in the coloring composition. Can be used. The precursor of the transparent resin can be used in an amount of 10 to 300 parts by weight, preferably 10 to 200 parts by weight, with respect to 100 parts by weight of the pigment in the coloring composition.

  Examples of the thermoplastic resin include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, and polyester resin. And acrylic resins, alkyd resins, polystyrene resins, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polybutadiene, polyethylene, polypropylene, polyimide resins, and the like.

  Examples of the thermosetting resin include epoxy resins, benzoguanamine resins, rosin-modified maleic acid resins, rosin-modified fumaric acid resins, melamine resins, urea resins, and phenol resins.

Examples of the photosensitive resin include (meth) acrylic compounds having a reactive substituent such as an isocyanate group, an aldehyde group, and an epoxy group on a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group, A resin obtained by reacting an acid and introducing a photocrosslinkable group such as a (meth) acryloyl group or a styryl group into the linear polymer is used.
Further, a linear polymer containing an acid anhydride such as a styrene-maleic anhydride copolymer or an α-olefin-maleic anhydride copolymer is converted into a (meth) acrylic compound having a hydroxyl group such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

  Monomers and oligomers that are precursors of transparent resins include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, polyethylene glycol di (meth) acrylate, pentaerythritol tri (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, melamine (meth) acrylate, various acrylic esters such as epoxy (meth) acrylate and methacrylic acid Examples include esters, (meth) acrylic acid, styrene, vinyl acetate, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, and acrylonitrile. These can be used alone or in admixture of two or more.

When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the coloring composition.
Examples of the photopolymerization initiator include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- Hydroxycyclohexyl phenyl ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane- Acetophenone photopolymerization initiators such as 1-one, benzoin photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzyldimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4 -F Benzophenone photopolymerization initiators such as nylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone Thioxanthone photopolymerization initiators such as 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4, 6-bis (trichloromethyl) -s-triazine, 2- (p-tolyl) -4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -s- Triazine, 2,4-bis (trichloro Til) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, etc. A polymerization initiator, a borate photopolymerization initiator, a carbazole photopolymerization initiator, an imidazole photopolymerization initiator, or the like is used.
A photoinitiator can be used in the amount of 5-200 weight part with respect to 100 weight part of pigments in a coloring composition, Preferably it is 10-150 weight part.

The above photopolymerization initiators are used alone or in combination of two or more. As sensitizers, α-acyloxy ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone. , Camphorquinone, ethyl anthraquinone, 4,4′-diethylisophthalophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 4,4′-diethylaminobenzophenone, etc. It can also be used together.
The sensitizer can be contained in an amount of 0.1 to 60 parts by weight with respect to 100 parts by weight of the photopolymerization initiator.

Furthermore, the coloring composition can contain a polyfunctional thiol that functions as a chain transfer agent. The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris (2-hydroxyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimerca DOO -s- triazine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.
The polyfunctional thiol can be used in an amount of 0.2 to 150 parts by weight, preferably 0.2 to 100 parts by weight, with respect to 100 parts by weight of the pigment in the coloring composition.

In addition, a solvent is used to facilitate the formation of a filter segment by sufficiently dispersing the pigment in a pigment carrier and applying it on a transparent substrate such as a glass substrate so that the dry film thickness is 0.2 to 5 μm. Can be contained. Examples of the solvent include cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, ethylbenzene, ethylene glycol diethyl ether, xylene, ethyl cellosolve, methyl-n amyl ketone, propylene glycol monomethyl ether, toluene, Examples include methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvent, and the like. These may be used alone or in combination.
The solvent can be used in an amount of 800 to 4000 parts by weight, preferably 1000 to 2500 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The coloring composition comprises one or more pigments, if necessary, together with the above photopolymerization initiator, in a pigment carrier and an organic solvent, such as a three roll mill, a two roll mill, a sand mill, a kneader, and an attritor. It can be manufactured using dispersion means. Moreover, the coloring composition containing 2 or more types of pigments can also be manufactured by mixing each pigment separately finely dispersed in a pigment carrier and an organic solvent.

When the pigment is dispersed in the pigment carrier and the organic solvent, a dispersion aid such as a resin-type pigment dispersant, a surfactant, or a pigment derivative can be appropriately contained.
Since the dispersion aid is excellent in pigment dispersion and has a great effect of preventing re-aggregation of the pigment after dispersion, a coloring composition comprising a pigment dispersed in a pigment carrier and an organic solvent using a dispersion aid is used. If so, a color filter excellent in transparency can be obtained. The dispersion aid can be used in an amount of 0.1 to 40 parts by weight, preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

The resin-type pigment dispersant has a pigment-affinity part that has the property of adsorbing to the pigment and a part that is compatible with the pigment carrier, and adsorbs to the pigment to stabilize the dispersion of the pigment on the pigment carrier. It works.
Specific examples of resin-type pigment dispersants include polycarboxylic acid esters such as polyurethane and polyacrylate, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid (partial) amine salts, polycarboxylic acid ammonium salts, and polycarboxylic acid alkylamines. Salts, polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl group-containing polycarboxylic acid esters, their modified products, amides formed by the reaction of poly (lower alkylene imines) with polyesters having free carboxyl groups, and the like Water-based dispersants such as oily dispersants such as salts, (meth) acrylic acid-styrene copolymers, (meth) acrylic acid- (meth) acrylic acid ester copolymers, styrene-maleic acid copolymers, polyvinyl alcohol, polyvinylpyrrolidone Resin, water-soluble polymer, polyester Modified polyacrylate, ethylene oxide / propylene oxide addition compound, phosphate ester-based and the like are used, they can be used alone or in admixture of two or more.

Surfactants include polyoxyethylene alkyl ether sulfate, sodium dodecylbenzenesulfonate, alkali salt of styrene-acrylic acid copolymer, sodium alkylnaphthalenesulfonate, sodium alkyldiphenyletherdisulfonate, lauryl sulfate monoethanolamine, lauryl Anionic surfactants such as triethanolamine sulfate, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate, monoethanolamine of styrene-acrylic acid copolymer, polyoxyethylene alkyl ether phosphate; Polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene Nonionic surfactants such as alkyl ether phosphates, polyoxyethylene sorbitan monostearate, and polyethylene glycol monolaurate; chaotic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts; alkyldimethylamino Examples include amphoteric surfactants such as alkylbetaines such as betaine acetate and alkylimidazolines, and these can be used alone or in admixture of two or more.

The dye derivative is a compound in which a substituent is introduced into an organic dye, and is preferably close to the hue of the pigment to be used. However, if the addition amount is small, those having different hues may be used.
Organic dyes also include light yellow aromatic polycyclic compounds such as naphthalene and anthraquinone that are not generally called dyes. Examples of the dye derivatives are described in JP-A-63-305173, JP-B-57-15620, JP-B-59-40172, JP-B-63-17102, JP-B-5-9469, and the like. You can use what you have. In particular, a pigment derivative having a basic group is preferably used because it has a large pigment dispersion effect. These can be used alone or in admixture of two or more.

  The coloring composition can contain a storage stabilizer in order to stabilize the viscosity with time of the composition. Examples of storage stabilizers include quaternary ammonium chlorides such as benzyltrimethyl chloride and diethylhydroxyamine, organic acids such as lactic acid and oxalic acid, and organic acids such as methyl ether, t-butylpyrocatechol, tetraethylphosphine, and tetraphenylphosphine. Examples thereof include phosphine and phosphite. The storage stabilizer can be contained in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

In addition, the coloring composition may contain an adhesion improving agent such as a silane coupling agent in order to improve the adhesion to the substrate.
Examples of the silane coupling agent include vinyl silanes such as vinyltris (β-methoxyethoxy) silane, vinylethoxysilane, and vinyltrimethoxysilane, (meth) acrylsilanes such as γ-methacryloxypropyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) methyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ) Epoxysilanes such as methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) γ-aminopro Lutriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N Examples include aminosilanes such as -phenyl-γ-aminopropyltriethoxysilane, thiosilanes such as γ-mercaptopropyltrimethoxysilane, and γ-mercaptopropyltriethoxysilane. The silane coupling agent can be contained in an amount of 0.01 to 100 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

The coloring composition can be prepared in the form of gravure offset printing ink, waterless offset printing ink, inkjet ink, silk screen printing ink, solvent development type or alkali development type color resist. The colored resist is obtained by dispersing a dye in a composition containing a thermoplastic resin, a thermosetting resin or a photosensitive resin, a monomer, a photopolymerization initiator, and an organic solvent.
The pigment is preferably contained in a proportion of 5 to 70% by weight based on the total solid content of the colored composition (100% by weight). More preferably, it is contained in a proportion of 20 to 50% by weight, and the remainder consists essentially of a resinous binder provided by a pigment carrier.
The colored composition is removed by means of centrifugal separation, sintering filter, membrane filter, etc. to remove coarse particles of 5 μm or more, preferably coarse particles of 1 μm or more, more preferably 0.5 μm or more and coarse particles It is preferable to carry out.

  The red pixel, the green pixel, and the blue pixel in the color filter of the present invention are formed on the transparent substrate by using the above-described colored compositions by a printing method or a photolithography method.

  As the transparent substrate, glass plates such as soda lime glass, low alkali borosilicate glass and non-alkali aluminoborosilicate glass, and resin plates such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate are used. In addition, a transparent electrode made of a combination of metal oxides such as indium oxide, tin oxide, zinc oxide and antimony oxide is formed on the surface of the glass plate or resin plate for driving the liquid crystal after the liquid crystal panel is formed. Also good.

  The formation of each color filter segment by the printing method can be patterned simply by repeating the printing and drying of the colored composition prepared as the above various printing inks. Therefore, the color filter manufacturing method is low-cost and excellent in mass productivity. ing. Furthermore, it is possible to print a fine pattern having high dimensional accuracy and smoothness by the development of printing technology. In order to perform printing, it is preferable that the ink does not dry and solidify on the printing plate or on the blanket. Control of ink fluidity on a printing press is also important, and ink viscosity can be adjusted with a dispersant or extender pigment.

  The ink jet method is a method in which an ink jet apparatus in which a plurality of fine discharge ports (ink jet heads) are arranged for each color is directly printed on a transparent substrate or a substrate on which an active element such as a TFT is formed.

When each color pixel is formed by a photolithography method, the coloring composition prepared as the solvent developing type or alkali developing type coloring resist is applied to a transparent substrate by spray coating, spin coating, slit coating, roll coating, or the like. To apply a dry film thickness of 0.2 to 10 μm.
When drying the coating film, a vacuum dryer, a convection oven, an IR oven, a hot plate, or the like may be used. If necessary, the dried film is exposed to ultraviolet light through a mask having a predetermined pattern provided in contact with or non-contact with the film.
Then, after immersing in a solvent or alkali developer or spraying the developer by spraying or the like to remove the uncured portion to form a desired pattern, the same operation is repeated for other colors to produce a color filter. be able to.
Furthermore, in order to accelerate the polymerization of the colored resist, heating can be performed as necessary. According to the photolithography method, a color filter with higher accuracy than the above printing method can be manufactured.

In development, an aqueous solution such as sodium carbonate or sodium hydroxide is used as an alkali developer, and an organic alkali such as dimethylbenzylamine or triethanolamine can also be used. Moreover, an antifoamer and surfactant can also be added to a developing solution. As a development processing method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid accumulation) development method, or the like can be applied.
In order to increase the UV exposure sensitivity, after coating and drying the colored resist, a water-soluble or alkaline water-soluble resin such as polyvinyl alcohol or a water-soluble acrylic resin is applied and dried to form a film that prevents polymerization inhibition by oxygen. Thereafter, ultraviolet exposure can also be performed.

The color filter of the present invention can be produced by an electrodeposition method, a transfer method, an ink jet method or the like in addition to the above method. The electrodeposition method is a method for producing a color filter by using a transparent conductive film formed on a transparent substrate and forming each color filter segment on the transparent conductive film by electrophoresis of colloidal particles. is there.
The transfer method is a method in which a color filter layer is formed in advance on the surface of a peelable transfer base sheet, and this color filter layer is transferred to a desired transparent substrate.

  Next, a liquid crystal display device provided with the color filter of the present invention will be described.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display device provided with the color filter of the present invention.
A device 4 shown in FIG. 2 is a typical example of a TFT drive type liquid crystal display device for a notebook personal computer, and includes a pair of transparent substrates 5 and 6 disposed so as to be opposed to each other. (LC) is enclosed. A TFT (thin film transistor) array 7 is formed on the inner surface of the first transparent substrate 5, and a transparent electrode layer 8 made of, for example, ITO is formed thereon. An alignment layer 9 is provided on the transparent electrode layer 8. Further, on the outer surface of the transparent substrate 5, a polarizing plate 10 including a retardation film is formed.

  On the other hand, the color filter 11 of the present invention is formed on the inner surface of the second transparent substrate 6. The red, green and blue filter segments constituting the color filter 11 are separated by a black matrix (not shown). A transparent protective film (not shown) is formed as needed to cover the color filter 11, and a transparent electrode layer 12 made of, for example, ITO is formed thereon as necessary, covering the transparent electrode layer 12. An alignment layer 13 is provided. A polarizing plate 14 is formed on the outer surface of the transparent substrate 6. Note that a backlight unit 16 including a backlight light source 15 is provided below the polarizing plate 10.

  Hereinafter, embodiments of the present invention will be described with specific examples. In the examples and comparative examples, “parts” means “parts by weight”. The pigment symbol indicates a color index number. For example, “PG36” represents “CI Pigment Green 36”.

Pigment Production Pigments used in Examples and Comparative Examples were produced by the following method.

[Production Example 1]
120 parts of halogenated copper phthalocyanine-based green pigment (“Lionol Green 6YK” manufactured by Toyo Ink Manufacturing Co., Ltd.), 1600 parts of crushed salt and 270 parts of diethylene glycol were charged into a stainless steel 1 gallon kneader (Inoue Seisakusho) at 70 ° C. Kneaded for 12 hours.
The mixture was poured into 5000 parts of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained PG36 which is 117 parts of salt milling process pigments.

[Production Example 2]
120 parts of halogenated zinc phthalocyanine-based green pigment (“Phalocyline Green A110” manufactured by Dainippon Ink and Chemicals, Inc.), 1600 parts of ground sodium chloride, and 270 parts of diethylene glycol were charged into a 1 gallon kneader (manufactured by Inoue Seisakusho), 70 The mixture was kneaded for 12 hours. The mixture was poured into 5000 parts of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained PG58 which is 117 parts of salt milling process pigments.

-Preparation of acrylic resin solution Put 800 parts of cyclohexanone in a reaction vessel and inject nitrogen gas into the vessel at 100 ° C.
The mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out the polymerization reaction.
Styrene 60.0 parts Methacrylic acid 60.0 parts Methyl methacrylate 65.0 parts Butyl methacrylate 65.0 parts Azobisisobutyronitrile 10.0 parts After dropwise addition, the mixture is further reacted at 100 ° C for 3 hours, and then azo A solution in which 2.0 parts of bisisobutyronitrile was dissolved in 50 parts of cyclohexanone was added, and the reaction was further continued at 100 ° C. for 1 hour to synthesize a resin solution. After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20%. An acrylic resin solution was prepared.

・ Preparation of pigment dispersion In order to improve the dispersibility of the above PG36 and PG58, an acrylic resin solution, PY150 ("E4GN" manufactured by LANXESS), a pigment derivative, and a solution mixed with an organic solvent were uniformly stirred and mixed. Thereafter, zirconia beads having a diameter of 1 mm were used for dispersion for 5 hours by a sand mill, followed by filtration with a 5 μm filter to obtain a pigment dispersion of PG36 and PG58. In order to improve the dispersibility of yellow pigments PY138 and PY150, a solution mixed with an acrylic resin solution, a pigment derivative, and an organic solvent is uniformly stirred and mixed, and then zirconia beads having a diameter of 1 mm are used in a sand mill. After dispersing for 5 hours, the mixture was filtered through a 5 μm filter to obtain a pigment dispersion of PY138 and PY150.

The following commercially available compound (I) was used as a compound having a melamine skeleton.
Melamine compound: Nippon Carbide Industries Nicarax MX-750

R1 is a hydrogen atom, R2 is a —CH ₂ OH group, and R3 to R6 are —CH ₂ OCH ₃ groups.

-Preparation of colored composition Next, the mixture (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then filtered through a 1 µm filter to obtain a green colored composition. At this time, when the green coloring composition formed a green pixel, the film thickness was 2.6 μm, the chromaticity value was CIE chromaticity coordinates, and when C = 0, x = 0.286 when y = 0.603. It was adjusted to fall within the range of ~ 0.296. Note that the chromaticity value is not limited to this range.

・ Monomer: Trimethylolpropane triacrylate (“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Organic solvent: cyclohexanone.

-Preparation of green pixel Each resist shown in Table 1 was applied to a glass substrate by spin coating, and then pre-baked at 70 ° C for 2 minutes in a clean oven. Next, the substrate was cooled to room temperature, and then exposed to ultraviolet rays using an ultrahigh pressure mercury lamp. Thereafter, the substrate was spray-developed with an aqueous sodium carbonate solution, washed with ion-exchanged water, and air-dried. Then, in a clean oven, 23
Baking was performed at 0 ° C. for 20 minutes to obtain a green pixel.

  In the present invention, the chromaticity in the XYZ color system chromaticity diagram was measured using a spectrophotometer ("OSP-200" manufactured by Olympus).

In the present invention, the thickness direction retardation value is from 400 nm from an orientation inclined 45 ° from the normal direction of the substrate on which the coating film is formed using a transmission spectroscopic ellipsometer (“M-220” manufactured by JASCO Corporation). Measurements were made at a wavelength of 5 nm in the range of 700 nm to obtain an ellipso parameter δ. A retardation value Δ (λ) was calculated from Δ = δ / 360 × λ, and using this value, a three-dimensional refractive index was calculated, and a thickness direction retardation value (R _th ) was calculated from the next. At this time, the green colored pixel was measured at a wavelength of 550 nm.
R _th = {(Nx + Ny) / 2−Nz} × d
In the formula, Nx is a refractive index in the x direction in the plane of the colored pixel layer, Ny is a refractive index in the y direction in the plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. , Nx is a slow axis where Nx ≧ Ny. d is the thickness (nm) of the colored pixel layer.

Table 1 shows the Rth value of each green pixel fabricated as described above. As a result, while the R _th of the green pixels contained only PG58 was 1.9 nm, at most R _th in Examples 1 and 2 contained the melamine compound in order to plus the R _th 25. It was possible to increase to 6 nm. In Examples 3 and 4 containing PG36 to reduce R _th can drop to -16.2nm the R _th at the maximum, 9.1 nm at most R _th in Examples 5 and 6 containing PY138 Could be lowered. Further, in Example 7 which contains the PG36 and PY138 could be lowered to 21.3nm a maximum of R _th.

From the above, in the green pixel containing PG58, by including one or more of PG36, PY138, or melamine compound in an appropriate amount within a range that does not affect the formation of the green pixel and chromaticity, brightness, and contrast, It has been found that an arbitrary value can be selected within a range of R _th from −21.3 nm to 25.6 nm. As a result, in various liquid crystal display devices having different configurations and structures, the use of the color filter formed with green pixels capable of controlling _Rth of the present invention can improve the reduction in visibility when the screen is observed from an oblique direction. it is conceivable that.

1 is a schematic cross-sectional view of a color filter according to an embodiment of the present invention. It is a schematic sectional view which shows an example of the liquid crystal display device provided with the color filter of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Black matrix 3 ... Colored pixel 4 ... Liquid crystal display device 5, 6 ... Transparent substrate 7 ... TFT array 8, 12 ... Transparent electrode 9, 13 ... Alignment layers 10, 14 ... Polarizing plate 11 ... Color filter 15 ... Backlight source 16 ... Backlight unit

Claims (2)

At least C.I. I. Pigment Green 58, melamine compound, C.I. I. Pigment Green 36, C.I. I. A retardation value (R _th ) in the thickness direction formed using a pigment containing transparent pigment 138, a transparent resin, a photopolymerizable monomer, and a photocurable green coloring composition mainly containing a solvent is -21. A color filter substrate comprising a green pixel in a range of 3 nm to 25.6 nm.   A liquid crystal display device using the color filter substrate according to claim 1.

Images