JP2011100028A - Green-colored composition, color filter using the same, and liquid crystal display device equipped with the color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a green-colored composition for a color filter, which achieves both oblique visibility and high brightness of a liquid crystal display device, to provide a color filer formed by using the composition, and to provide a liquid crystal display device equipped with the color filter and having both oblique visibility and high brightness. <P>SOLUTION: The green-colored composition for a color filter includes: a pigment containing C.I.Pigment Green 58 and C.I.Pigment Green 36 in a weight ratio of 99:1 to 35:65; a transparent resin, a solvent and a photo-crosslinking agent. The retardation value Rth in the thickness direction, represented by the formula below, of a green colored layer formed by the green-colored composition for a color filter is -15 to +15 nm. In the formula, Rth=ä(Nx+Ny)/2-Nz}×d, Nx represents refractive index in x-direction in the xy plane of a colored pixel layer, Ny represents refractive index in y-direction in the xy plane of a colored pixel layer, Nz represents refractive index in the thickness direction of the colored pixel layer, and d represents the thickness (mm) of the colored pixel layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a green coloring composition, a color filter using the green coloring composition, and a liquid crystal display device including the color filter, and in particular, a green coloring composition capable of achieving both high contrast and oblique visibility. The present invention also relates to a color filter using the green coloring composition and a liquid crystal display device including the color filter.

In recent years, liquid crystal display devices have been evaluated for space saving, light weight, power saving, and the like due to their thinness, and recently they have been rapidly spread to television applications. For TV applications, it is required to further improve performance such as brightness, contrast and omnidirectional visibility, and these display devices may be applied in combination with a phase difference control layer and a linear polarizing plate. Many.
Particularly in recent years, in a vertical alignment mode liquid crystal display capable of high contrast display, a retardation film (negative C plate) having an optical axis perpendicular to the substrate and having negative birefringence anisotropy, and an optical axis on the substrate. A horizontal retardation film (positive A plate) having positive birefringence anisotropy is used in combination (for example, see Patent Document 1).

  As these retardation films, usually a stretched polycarbonate film or the like, or a retardation control film in which a liquid crystal material having birefringence anisotropy is applied to a triacetyl cellulose film or the like is used.

  However, in these retardation films, the retardation amount is kept uniform in the plane, so the optimum retardation amount is not set for each actually displayed pixel, and the optimum retardation compensation is not necessarily performed. It is not done.

  The reason is that when the thickness direction retardation values (hereinafter referred to as Rth (R), Rth (G), and Rth (B)) of the red, green, and blue colored pixel layers constituting the color filter are different from each other, This causes a problem that coloring is observed during black display when viewed from above. In particular, the thickness direction retardation values of the colored pixel layers of red, green, and blue are not uniform, that is, Rth (R) <Rth (G)> Rth (B), or Rth (R)> Rth (G) <Rth ( B), the optical compensation layer that exhibits chromatic dispersion in one direction (continuous) with respect to the wavelength of the light has a thickness direction retardation value that is uneven for each color, with a high level of display quality that is required recently. It becomes impossible to compensate by level.

  Since the retardation of the color filter was relatively small compared to other members used in the liquid crystal display device, this problem has not been emphasized so far, but high contrast and wide viewing angle characteristics are required. In LCD TVs, it has become a level that cannot be ignored. In particular, high-contrast liquid crystal display devices having 1000 or 3000 or more have been required to have high image quality required for black display.

  Specifically, the visibility from the front (vertical direction) is good with respect to the display surface, but only a specific color in the visibility observed from an oblique angle such as 45 degrees (hereinafter referred to as oblique visibility). As a result, light is leaked, and as a result, coloring such as reddish, bluedish, or greenish is produced during black display.

  In order to show continuous wavelength dispersion, it is necessary to satisfy the relationship of Rth (B)> Rth (G)> Rth (R) and Rth (B) <Rth (G) <Rth (R). Each colored layer may have Rth> 0 or Rth <0 depending on the pigment system and material system used, and does not necessarily exhibit continuous wavelength dispersion.

  Since the green pixel has transmittance near the center of visible light, that is, in the vicinity of 500 to 600 nm, if the Rth (G) of the green pixel can be freely controlled, the values of Rth (B) and Rth (R) Rth (B)> Rth (G)> Rth (R) or Rth (B) <Rth (G) <Rth (R) can be satisfied to show continuous wavelength dispersion It becomes.

  Each colored layer in the color filter often falls within the range of Rth = -15 to +15, although it varies depending on the pigment system and material system used. Therefore, if the value of Rth (G) can be freely controlled to -15 to +15, it will be continuous regardless of the value of Rth (R) or Rth (B) in the range of -15 to +15. Chromatic dispersion can be maintained.

  Conversely, if red coloring occurs in oblique visibility during black display, black display can be optimized by controlling the retardation of the green pixel layer.

  On the other hand, as a method for enabling phase difference control, an attempt is made to make retardation compensation more optimal by controlling retardation according to the wavelength of transmitted light using a phase difference control layer using a polymerized liquid crystal. (For example, refer to Patent Document 2).

  However, since the phase difference control layer is formed after forming the colored pixel portion, there is a problem that the number of steps increases, and it is required to control the phase difference of the colored pixels without increasing the number of steps. It was.

JP-A-10-153802 JP, 2005-148118, A On the other hand, brightness is mentioned as a quality item requested | required of a color filter other than diagonal visibility. Increasing the lightness increases the light transmittance, reduces the number of backlights that are light sources, and enables the suppression of power consumption. Yes. In order to respond to this trend of increasing brightness, it is becoming mainstream to use a zinc halide phthalocyanine green pigment (CI Pigment Green 58, hereinafter referred to as PG58) in the green colored layer. However, since PG58 has a tendency to increase the phase difference as a physical property, it is difficult to freely control the phase difference between -15 and +15 with PG58 alone, and it is difficult to achieve both oblique visibility and high brightness. It had been.

  The present invention has been made under the circumstances as described above, and a green coloring composition for a color filter that enables both oblique visibility and high brightness of a liquid crystal display device, a color filter formed thereby, and the color filter thereof An object of the present invention is to provide a liquid crystal display device having both oblique visibility and high brightness.

  A first aspect of the present invention is C.I. I. Pigment Green 58 and C.I. I. A green coloring composition for a color filter comprising Pigment Green 36 in a weight ratio of 99: 1 to 35:65, a transparent resin, a solvent, and a photocrosslinking agent. Provided is a green coloring composition for a color filter, wherein a retardation value Rth in a thickness direction represented by the following formula of a green coloring layer formed of the green coloring composition is −15 to +15 nm.

Rth = {(Nx + Ny) / 2−Nz} × d
(Where Nx is the refractive index in the x direction in the xy plane of the colored layer, Ny is the refractive index in the y direction in the xy plane of the colored pixel layer, and Nz is the refractive index in the thickness direction of the colored pixel layer, d represents the thickness (nm) of the colored layer.)
According to a second aspect of the present invention, a plurality of color pixels including a red pixel, a green pixel, and a blue pixel are provided on a transparent substrate, and the green pixel is formed from the above-described green coloring composition. Provide a color filter.

  A third aspect of the present invention provides a liquid crystal display device using the color filter described above.

  ADVANTAGE OF THE INVENTION According to this invention, the green coloring composition for color filters which makes compatible the diagonal visibility of a liquid crystal display device and high brightness is provided. In addition, a color filter formed thereby and a liquid crystal display device including the color filter and having both oblique visibility and high brightness are provided.

It is a schematic sectional drawing which shows the color filter which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows an example of the liquid crystal display device provided with the color filter which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described.

  The thickness direction retardation value of the colored pixel is determined by irradiating the colored pixel with continuous light including the wavelength of the transmitted light peak region in the visible region (roughly the wavelength of light from 380 nm to 780 nm) from the front and a plurality of inclined angles. It can be obtained by measuring a three-dimensional refractive index using a phase difference measuring device such as a spectroscopic ellipsometer.

  For example, a phase difference measurement is performed with light from at least two directions of a front surface and an incident angle of 45 degrees at a wavelength of 620 nm for a red pixel, 550 nm for a green pixel, and 450 nm for a blue pixel, and a three-dimensional refractive index of Nx, Ny, and Nz. Then, the thickness direction retardation value (Rth) is calculated from the following equation.

Rth = {(Nx + Ny) / 2−Nz} × d
In the formula, Nx is a refractive index in the x direction in the xy plane of the colored pixel, Ny is a refractive index in the y direction in the xy plane of the colored pixel, and Nz is a refractive index in the thickness direction of the colored pixel. Where Nx is the slow axis where Nx ≧ Ny, and d is the thickness (nm) of the colored pixel layer.

  At this time, when the substrate to be measured is a color filter, the phase difference value of a single pixel is measured by measuring through a mask processed so as to transmit only a single colored pixel layer of R, G, and B. Can be requested.

  Further, for example, when light having a wavelength of 620 nm is used as incident light, a phase difference value caused only by a red pixel, in the case of 550 nm, a phase difference value caused only by a green pixel, and in a case of 450 nm, a blue pixel It is possible to estimate an approximate value of each single colored pixel as the phase difference value caused only by the above.

  In addition, when the substrate to be measured is a single colored pixel of any of R, G, and B (a configuration in which a coating film of a single color filter coloring composition is formed on a transparent substrate), the position is measured without a mask. The phase difference can be measured.

  The green coloring composition for a color filter according to the first embodiment of the present invention includes a pigment, a transparent resin, a solvent, and a photocrosslinking agent. The pigment is C.I. I. Pigment Green 58 and C.I. I. Pigment Green 36 is contained at a ratio of 99: 1 to 35:65 by weight.

  The thickness direction retardation value Rth represented by the above formula of the green colored layer formed of such a green colored composition is −15 to +15 nm.

  We have described C.I. I. Pigment Green 58 and C.I. I. It has been found that a green coloring composition in which Rth is in the range of −15 to +15 can be effectively obtained by using together Pigment Green 36 and making the mixing ratio appropriate.

  In the green coloring composition according to this embodiment, C.I. I. Pigment Green 58 total weight of PG58, C.I. I. When the total weight of Pigment Green 36 is PG36, if the amount of PG58 mixed in the Green pigment is large, the transmittance and contrast become high, and Rth (G)> 0. However, if the ratio of PG36 is less than 1%, it is not possible to obtain the effect of improving dispersibility by blending this ratio. On the other hand, when PG 36 is large, Rth (G) <0, which can be controlled to a large negative phase difference value. However, if PG36 is larger than 65%, the transmittance and contrast are significantly lowered. In order to have a thickness direction retardation such that Rth = -15 to +15 without impairing the transmittance and contrast, PG58: PG36 = 99: 1 to 35:65 must be satisfied.

  Note that C.I. I. Pigment Green 58 and C.I. I. When the weight ratio of Pigment Green 36 is out of the above range, the retardation value Rth in the thickness direction is out of the range of −15 to +15 nm, and the color filter obtained using this green coloring composition is provided. The oblique visibility of the liquid crystal display device to be deteriorated.

  As described above, according to the green coloring composition according to the first embodiment of the present invention, by appropriately controlling the ratio of the contained pigment, the transmittance and contrast in the thickness direction of the green pixel are not impaired. The phase difference can be adjusted to a desired value. As a result, it is possible to obtain a color filter having a contrast value of 1000 or more, or 3000 or more, high quality, and appropriate optical compensation for each wavelength.

  Next, a color filter according to the second embodiment of the present invention will be described.

  As shown in FIG. 1, the color filter according to the second embodiment of the present invention includes a black matrix 2 that is a light-shielding layer on a glass substrate 1, and is a region divided by the black matrix 2 on the glass substrate 1. In addition, at least three colored pixels of a red pixel 3R, a green pixel 3G, and a blue pixel 3B 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.

  Below, the method for obtaining the color filter which concerns on this embodiment is demonstrated. The color filter according to the present embodiment includes a plurality of color pixels on at least a transparent substrate. The plurality of colors is a combination of red, green, and blue (R, G, and B). In addition to this, yellow, magenta, and cyan (YMC) can be appropriately combined.

  The transparent substrate used preferably has a certain degree of transmittance with respect to visible light, and more preferably has a transmittance of 80% or more. In general, it may be one used in a liquid crystal display device, and examples thereof include a plastic substrate such as PET and glass, but a glass substrate is usually preferable. In the case of using a light shielding pattern, a pattern in which a metal thin film such as chromium or a light shielding resin is previously formed on the transparent substrate by a known method may be used.

  The colored pixels on the transparent substrate may be produced by any known method such as an inkjet method, a printing method, a photoresist method, or an etching method. However, in consideration of high definition, controllability and reproducibility of spectral characteristics, the photoresist method is preferable. In the photoresist method, a colored composition obtained by dispersing a pigment in a transparent resin in a suitable solvent together with a photopolymerization initiator and a photocrosslinking agent is coated on a transparent substrate to form a colored layer. In this method, the colored layer is subjected to pattern exposure and then developed to repeatedly form a single color pixel for each color.

  When forming the colored layer which comprises the pixel with which the color filter which concerns on this embodiment comprises by the photolitho method, first, the photosensitive coloring composition is prepared with the following method.

  A pigment serving as a colorant is dispersed in a suitable solvent together with a photocrosslinking agent and a photopolymerization initiator. The dispersing method includes various methods such as a mill base, three rolls, and a jet mill, and is not particularly limited.

  Specific examples of organic pigments that can be used in the colored composition for forming the colored layer of the color filter according to this embodiment are shown below by color index numbers.

  Red coloring compositions for forming red pixels include C.I. I. Pigment Red 7, 9, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, 81: 1, 81: 2, 81: 3, 97, 122, 123, 146, 149, 168, 177, 178, 179, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, 226, 227, 228, 240, 246, 254, 255, Red pigments such as H.264, 272, and 279 can be used. A yellow pigment and an orange pigment can be used in combination with the red coloring composition.

  Examples of yellow pigments include C.I. I. In addition to Pigment Yellow 150, 139, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 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, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 144, 146, 147, 148, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 1 75, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 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 green coloring composition for forming a green pixel contains C.I. used as an essential component in the present invention. I. In addition to Pigment Green 58 and 36, for example, C.I. I. Pigment Green 7, 37 or the like can be used. The green coloring composition can be used in combination with the same yellow pigment as the red coloring composition.

  As described above, the blue coloring composition for forming a blue pixel may be C.I. I. Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4 blue pigment, C.I. I. Pigment Violet 23 purple pigment is used.

  In addition, in combination with the above organic pigments, in order to ensure good coatability, sensitivity, developability, etc. while balancing saturation and lightness, inorganic pigments should be used in combination as long as the liquid crystal resistance is not lowered. Is also possible. Inorganic pigments include yellow lead, zinc yellow, red bean (red iron oxide (III)), cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green and other metal oxide powders, metal sulfide powders, metal powders, etc. Can be mentioned. Furthermore, for color matching, a dye can be contained within a range that does not deteriorate liquid crystal resistance and heat resistance.

  The coloring composition used in the color filter according to this embodiment is preferably a pigment dispersion in which a pigment is dispersed in a pigment carrier and an organic solvent. The pigment dispersion is prepared using a pigment, a binder resin, and a dispersion aid such as a resin-type pigment dispersant, a surfactant, or a pigment derivative.

  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 dispersion aid provided by the pigment carrier and a binder resin. 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.

〔dispersion〕
The green coloring composition according to the first embodiment of the present invention is a halogenated zinc phthalocyanine green pigment, C.I. I. Pigment Green 58 and C.I. I. Pigment Green 36 containing a green pigment dispersion, preferably together with a pigment derivative and / or dispersion aid, in a pigment carrier such as a binder resin and an organic solvent, in a three roll mill, a two roll mill, a sand mill, a kneader, It can be prepared by finely dispersing using various dispersing means such as an attritor. Alternatively, it can also be prepared by mixing separately dispersed several types of pigment dispersions.

[Dispersion aid]
When dispersing the pigment in the pigment carrier, a dispersion aid such as a resin-type dispersant, a surfactant, or a pigment derivative can be appropriately used. Since the dispersion aid is excellent in dispersing the pigment and has a great effect of preventing re-aggregation of the pigment after dispersion, a coloring composition obtained by dispersing the pigment in a pigment carrier and an organic solvent using the dispersion aid is used. When used, 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 alkyleneimines) 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 sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate, sodium dodecylbenzene sulfonate, alkali salt of styrene-acrylic acid copolymer, sodium stearate, sodium alkyl naphthalene sulfonate, sodium alkyl diphenyl ether disulfonate Anionic surfactants such as monoethanolamine lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, monoethanolamine stearate, 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.

  Examples of the pigment derivative include a compound in which a basic substituent, an acidic substituent, or a phthalimidomethyl group which may have a substituent is introduced into an organic pigment, anthraquinone, acridone or triazine. The structure is shown by the following general formula (1).

General formula (1):
P-Lm formula (1)
(However, P is an organic pigment residue, L is a basic substituent, an acidic substituent, or a compound having an optionally substituted phthalimidomethyl group, m is an integer of 1 to 4)
Examples of the pigment derivative are described in JP-A-63-305173, JP-B-57-15620, JP-B-59-40172, JP-B-63-17102, or JP-B-5-9469. What is currently used can be used, and these can be used individually or in mixture of 2 or more types.

  The blending amount of the pigment derivative is preferably 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, and most preferably 5 to 25 parts by weight with respect to 100 parts by weight of the pigment. When the pigment derivative is less than 1 part by weight with respect to 100 parts by weight of the pigment, the dispersibility may be deteriorated, and when it exceeds 50 parts by weight, the heat resistance and light resistance may be deteriorated.

  In the general formula (1), examples of the organic pigment constituting the organic pigment residue of P include the following.

For example, azo pigments such as diketopyrrolopyrrole pigments, azo, disazo, and polyazo;
Phthalocyanine pigments such as copper phthalocyanine, halogenated copper phthalocyanine, and metal-free phthalocyanine; anthraquinone pigments such as aminoanthraquinone, diaminodianthraquinone, anthrapyrimidine, flavantron, anthanthrone, indanthrone, pyranthrone, and violanthrone; quinacridone pigment Dioxazine pigments, perinone pigments, perylene pigments, thioindigo pigments, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, selenium pigments, and metal complex pigments.

  The coloring composition according to this embodiment can contain a binder resin. As binder resins, thermoplastic resins, thermosetting resins, alkali-soluble vinyl resins copolymerized with acidic group-containing ethylenically unsaturated monomers, and energy ray curable resins having ethylenically unsaturated active double bonds The spectral transmittance is 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 thermoplastic resin as the binder resin is, for example, butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin Polyester resins, vinyl resins, alkyd resins, polystyrene resins, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene (HDPE, LDPE), polybutadiene, and polyimide resins.

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

  When the green coloring composition for a color filter according to this embodiment is used in the form of an alkali developing type colored resist, an alkali copolymerized with an acidic group-containing ethylenically unsaturated monomer such as (meth) acrylic acid as a binder resin It is preferable to use a soluble vinyl resin.

  Further, as the binder resin, an energy ray curable resin having an ethylenically unsaturated active double bond can also be used. As a method for producing the resin, as a resin precursor, for example, a linear polymer having a reactive substituent such as a hydroxyl group, a carboxyl group, or an amino group is prepared, and an isocyanate group, an aldehyde group, an epoxy group, or the like is prepared. A method of obtaining a resin in which a photo-crosslinkable group such as a (meth) acryloyl group or a styryl group is introduced into the linear polymer by reacting a (meth) acrylic compound having a reactive substituent or cinnamic acid; A linear polymer containing an acid anhydride such as a styrene-maleic anhydride copolymer or an α-olefin-maleic anhydride copolymer is half-esterified with a (meth) acrylic compound having a hydroxyl group such as hydroxyalkyl (meth) acrylate. There is a method to make it.

  The binder resin can be used in an amount of 30 to 500% by weight, based on the total weight of the pigment dispersion. If it is less than 30% by weight, the film formability and various resistances are insufficient, and if it exceeds 500% by weight, the pigment concentration is low and color characteristics cannot be expressed.

  In addition, the binder resin includes a pigment adsorbing group and a carboxyl group that functions as an alkali-soluble group at the time of development, an aliphatic group that functions as an affinity group for the pigment carrier and solvent, from the viewpoint of pigment dispersibility, developability, and heat resistance. Since the balance of aromatic groups is important for pigment dispersibility, developability, and durability, the acid value is preferably in the range of 20 to 300 mgKOH / g. When the acid value is less than 20 mgKOH / g, the solubility in the developing solution is poor and it is difficult to form a fine pattern. When it exceeds 300 mgKOH / g, no fine pattern remains.

  As the photocrosslinking agent, a photopolymerizable monomer or oligomer can be used. Photopolymerizable monomers and oligomers include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, β-carboxyethyl ( (Meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Pentaerythritol tri (meth) acrylate, 1,6-hexanediol diglycidyl ether di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neo Pentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, methylolated melamine (meth) acrylate, epoxy (meth) acrylate, caprolactone Various acrylic esters and methacrylic esters such as modified dipentaerythritol hexaacrylate, urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-vinylformamide, acrylonitrile and the like can be mentioned. These can be used alone or in admixture of two or more.

  The addition amount of the photocrosslinking agent is preferably large as long as the coating property and development suitability are not impaired, and is about 10% to 80% by weight, more preferably 50% to 70%, based on the total solid content of the coloring composition. It is about wt%. If the addition amount is less than this range, the cross-linkability is insufficient and the liquid crystal resistance is deteriorated. The liquid solubility is remarkably lowered and the development suitability is poor.

  As photopolymerization initiators, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- Acetophenone compounds such as hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl Benzoin compounds such as dimethyl ketal; benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3 Benzophenone compounds such as 3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4- Thioxanthone compounds such as diethylthioxanthone; 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 (trichloromethyl) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloro) Methyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, Triazine compounds such as 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine; 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], Oxime ester compounds such as O- (acetyl) -N- (1-phenyl-2-oxo-2- (4′-methoxy-naphthyl) ethylidene) hydroxylamine; bis (2,4,6-trimethylbenzoyl) phenyl Phosphine compounds such as phosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 9,10-phenanthrenequinone, camphorquinone, ethyl anthraquino Quinone compounds such; borate compound; carbazole-based compounds; imidazole compounds; titanocene compounds and the like. These photopolymerization initiators can be used alone or in combination.

  The amount of the photopolymerization initiator used is preferably 0.5 to 50% by weight, more preferably 3 to 30% by weight, based on the total solid content of the colored composition.

  Further, as sensitizers, triethanolamine, methyldiethanolamine, triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, 2-Ethylhexyl 4-dimethylaminobenzoate, N, N-dimethylparatoluidine, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (ethylmethyl) Amine-based compounds such as amino) benzophenone can also be used in combination. These sensitizers can be used alone or in combination.

  The amount of the sensitizer used is preferably 0.5 to 60% by weight, more preferably 3 to 40% by weight based on the total amount of the photopolymerization initiator and the sensitizer.

  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, tris (2-hydroxyethyl) isocyanurate trimercaptopropionate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-to Azine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.

  The amount of the polyfunctional thiol used is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the total solid content of the colored composition. If it is less than 0.1% by mass, the effect of adding a polyfunctional thiol is insufficient, and if it exceeds 30% by mass, the sensitivity is too high and the resolution is lowered.

  If necessary, a resin having a planar structure group can also be used as a phase difference adjusting agent. By adding a resin capable of increasing or decreasing the retardation, it becomes possible to further control the phase difference (for example, JP-A-2008-185984). Examples of the phase difference adjusting agent include melamine resin, epoxy resin, and styrene resin.

  Examples of the melamine resin include alkylated melamine resins (methylated melamine resin, butylated melamine resin, etc.), mixed etherified melamine resins, and the like, which may be a high condensation type or a low condensation type. Any of these may be used alone or in admixture of two or more. Moreover, an epoxy resin can also be mixed and used as needed.

  Examples of the epoxy resin include glycerol / polyglycidyl ether, trimethylolpropane / polyglycidyl ether, resorcin / diglycidyl ether, neopentyl glycol / diglycidyl ether, 1,6-hexanediol / diglycidyl ether, ethylene glycol (polyethylene). Glycol) and diglycidyl ether. Also about these, it can use individually or in mixture of 2 or more types.

  Examples of the organic 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 can contain a storage stabilizer in order to stabilize the viscosity with time of the composition. Examples of the storage stabilizer 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, silk screen printing ink, solvent development type or alkali development type coloring 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 photocrosslinking agent, a photopolymerization initiator, and an organic solvent.

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

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

  When each colored pixel is formed by a photolithography method, the colored composition prepared as the solvent development type or alkali development type color resist is applied on a transparent substrate by spray coating, spin coating, slit coating, roll coating or the like. By a method, it apply | coats so that a dry film thickness may be set to 0.2-10 micrometers. 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 according to the present embodiment can be manufactured by an electrodeposition method, a transfer 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 above-described color filter will be described.

  FIG. 2 is a schematic sectional view of a liquid crystal display device according to the third embodiment of the present invention. A liquid crystal display 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 face each other. Liquid crystal (LC) is enclosed. The present invention includes a TN (Twisted Nematic), STN (Super Twisted Nematic), IPS (In-Plane Switching), VA (Vertical Alignment), OCB (Optically Compensated Birefring plate), etc. It is applicable to.

  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. A polarizing plate 10 is formed on the outer surface of the transparent substrate 5.

  On the other hand, the color filter 11 according to the above-described second embodiment 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 so as to cover the color filter 11, and further, a transparent electrode layer 12 made of, for example, ITO is formed thereon. Is provided. A polarizing plate 14 is formed on the outer surface of the transparent substrate 6. A backlight unit 16 including a three-wavelength lamp 15 is provided below the polarizing plate 10.

According to such a liquid crystal display device according to this embodiment, the values relating to the thickness direction retardation of the colored display pixels of red, green, and blue constituting the color filter are measured using an ellipsometer or a phase difference measuring device. Thus, even if the thickness of the colored display pixel formed on the substrate is 1 to 3 μm, the influence of interference due to the refractive index difference between the colored display pixel and the air layer or the substrate is included in the phase difference Δ. By obtaining the value related to the phase difference, the color filter can be evaluated with high accuracy from the correlation between this value and the visibility in the oblique direction of the liquid crystal display device.
As described above, according to the liquid crystal display device according to the third embodiment of the present invention, the variation in the polarization state of the light passing through the display area of each colored pixel is reduced, and the visibility in the oblique direction and the front is improved. In addition, the phase difference compensation for the entire panel can be performed simply and more optimally.

  Hereinafter, although the specific Example of this invention is given, this invention is not limited to this Example. In addition, since the material used in this embodiment is extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light, and it goes without saying that all operations are performed under a yellow or red light. In the examples and comparative examples, “parts” means “parts by weight”. The symbol of the pigment indicates a color index number. For example, “PG58” represents “CI Pigment Green 58” and “PY150” represents “CI Pigment Yellow 150”.

(Preparation of acrylic resin solution)
The mixture was heated to 100 ° C. while injecting nitrogen gas into a reaction vessel containing 800 parts of cyclohexanone, and a mixture of the following photocrosslinking agent and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out a 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 obtain an acrylic resin solution having a weight average molecular weight of about 40,000.

  After cooling to room temperature, about 2 g of the resin solution was sampled and dried by heating at 180 ° C. for 20 minutes, the nonvolatile content was measured, 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 resin-type dispersant solution)
A commercially available resin type dispersant (EFKA4300 manufactured by Ciba Japan Co., Ltd.) and ethylene glycol monomethyl ether acetate were used to prepare a solution having a nonvolatile content of 40% by weight and used as a resin type dispersant solution.

[Production of pigment dispersion]
Red Pigment 1 (CI Pigment Red 254, “IRGAPHOR RED B-CF” manufactured by Ciba Specialty Chemicals; R-1), Red Pigment 2 (CI Pigment Red 177, Ciba Specialty Chemicals) "CROMOPHTAL RED A2B"; R-2), Yellow Pigment 1 (CI Pigment Yellow 150, "FANCHON FAST YELLOW Y-5688" manufactured by BAYER; Y-1), acrylic resin solution, resin-type dispersant solution , And ethylene glycol monomethyl ether acetate were uniformly stirred and mixed in the composition (weight ratio) shown in Table 1 below, and then dispersed with an Eiger mill for 2 hours using zirconia beads having a diameter of 0.5 mm. Filter with a filter, pigment dispersion RP 1, to prepare a RP-2.

  Green Pigment 1 (CI Pigment Green 58, “FASTOGEN GREEN A10”; G-1) manufactured by Dainippon Ink & Chemicals, Inc .; Green Pigment 2 (CI Pigment Green 36, manufactured by Toyo Ink Manufacturing Co., Ltd. “ LIONOL GREEN 6YK "; G-2), yellow pigment 1 (CI Pigment Yellow 150," FANCHON FAST YELLOW Y-5688 "manufactured by BAYER; Y-1), yellow pigment 2 (C.I. Pigment Yellow 139) BASF "Pariotole Yellow D1819"; Y-2), acrylic resin solution, resin-type dispersant solution, and ethylene glycol monomethyl ether acetate are uniformly stirred and mixed in the composition (weight ratio) shown in Table 1 below. Zirconia with a diameter of 0.5 mm With over's, after 2 hours dispersed Eiger mill, filtered through a 5μm filter to prepare a pigment dispersion GP-1,2,3,4,5.

Blue Pigment 1 (CI Pigment Blue 15: 6, “LIONOL BLUE ES”; B-1) manufactured by Toyo Ink Mfg. Co., Ltd., Purple Pigment 1 (CI Pigment Violet 23, “LIONOGEN VIOLET” manufactured by Toyo Ink Mfg. Co., Ltd.) RL "; V-1), an acrylic resin solution, a resin-type dispersant solution, and ethylene glycol monomethyl ether acetate were uniformly stirred and mixed with the blending composition (weight ratio) shown in Table 1 below, and then a diameter of 0.5 mm was obtained. A zirconia bead was used for dispersion treatment with an Eiger mill for 2 hours, followed by filtration with a 5 μm filter to prepare a pigment dispersion BP-1.

[Examples 1 to 3, Comparative Examples 1 and 2]
[Preparation of colored composition]
A mixture of the compositions (weight ratio) shown in Table 2 below was stirred and mixed so as to be uniform, and then filtered through a 1 μm filter to obtain a colored composition of each color. In Table 2 below, GR1 is Example 1, GR-2 is Example 2, GR-3 is a green colored composition according to Example 3, GR4 is Comparative Example 1, and GR-5 is Comparative Example 2. This is a green coloring composition.

Photocrosslinking agent: alkyl-modified dipentaerythritol pentaacrylate (Nippon Kayaku "Kayarad D-310")
Photopolymerization initiator: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer: 4,4′-bis (diethylamino) benzophenone (“EAB-F” manufactured by Dougaya Chemical Co.)
Organic solvent: cyclohexanone [retardation modifier]
The following commercially available compounds were used as retardation adjusting agents.

Styrene-maleic compound: manufactured by Arakawa Chemical Industries (trade name ARASTOR 700)

[Preparation of coating film]
Prepare a melt-formed aluminosilicate thin glass sheet with a thickness of 0.7 mm as the substrate, wash it, and apply the colored composition obtained above onto the substrate on which the black matrix has been formed in advance by spin coating. Then, after drying under reduced pressure, exposure was performed so that the irradiation dose by the ultraviolet light source was 100 mJ / cm ² . Thereafter, post baking was performed at a temperature of 230 ° C. for 60 minutes to form a red coating film, a green coating film, and a blue coating film having a thickness of 2 μm.

  The chromaticity, spectral transmittance, and thickness direction retardation value of each coating film were measured. The measuring method is as follows.

[Chromaticity, spectral transmittance]
The chromaticity in the XYZ color system chromaticity diagram was measured using a spectrophotometer (OTSUKA LCF-1100M). Table 3 below shows the chromaticity of each color coating film prepared from each resist shown in Table 2 above.

[Thickness direction retardation value Rth]
Thickness direction retardation value is in the range of 400 nm to 700 nm from a direction 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 every 5 nm to obtain an ellipso parameter δ. A retardation value Δ (λ) was calculated from Δ = δ / 360 × λ, a three-dimensional refractive index was calculated using this value, and a thickness direction retardation value (Rth) was calculated from the following formula. However, the measurement was performed at a wavelength of 620 nm for red colored pixels.

Rth = {(Nx + Ny) / 2−Nz} × d
In the formula, Nx is a refractive index in the x direction in the xy plane of the colored pixel layer, Ny is a refractive index in the y direction in the xy plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. And let Nx be the slow axis where Nx ≧ Ny. d is the thickness (nm) of the colored pixel layer.

The thickness direction retardation value Rth of each color coating film produced from each resist shown in Table 2 is shown in Table 3 below.

  As shown in Table 3, GR1 (Example 1) in which PG58 / PG36≈94: 6, GR2 (Example 2) in which PG58 / PG36≈35.4: 64.6, PG58 / PG36 = 50: 50 In the case of GR3 [Example 3], since PG58 / PG36 is within the range of the present invention, Rth (G) is within a range of −15 to +15 nm, and the stability of the resist is good. Y was 60 or more.

  In contrast, GR4 (Comparative Example 1) with PG58 / PG36 = 100/0 (excluding PG36) exhibited Rth (G) = + 20, and the stability of the resist was low. GR5 of PG58 / PG36≈30 / 70 (Comparative Example 2) was Rth (G) = − 16, which was outside the scope of the present invention, and the brightness Y was as low as 60 or less.

Production of color filter A color filter was produced by combining the color resists shown in Table 2 above by the method described below.

[Example 4]
First, a red resist (RR-1) was applied by spin coating to a glass substrate on which a black matrix was previously formed, and then prebaked at 70 ° C. for 20 minutes in a clean oven. Next, the substrate was cooled to room temperature, and then exposed to ultraviolet rays through a photomask using an ultrahigh pressure mercury lamp.

Thereafter, the substrate was spray-developed using a sodium carbonate aqueous solution at 23 ° C., washed with ion-exchanged water, and air-dried. Further, post-baking was performed at 230 ° C. for 30 minutes in a clean oven to form striped red pixels on the substrate.

  Next, a green resist (GR-1: PG58 / PG36≈94: 6) is used to form a green pixel in the same manner as a red pixel, and further, a blue resist is used using a blue resist (BR-1). A color filter was obtained. The formed film thickness of each color pixel was 2.0 μm.

[Example 5]
Red resist from (RR-1) to (RR-2), green resist from (GR-1) to (GR-2: PG58 / PG36≈35.4: 64.6), blue resist (BR-1) To (BR-2), a color filter was obtained in the same manner as in Example 4.

[Example 6]
Except that the red resist was changed from (RR-1) to (RR-2), and the green resist was changed from (GR-1) to (GR-3: PG58 / PG36 = 50: 50), the same as in Example 4. A color filter was obtained.

[Comparative Example 3]
A color filter was obtained in the same manner as in Example 4 except that the green resist was changed from (GR-1) to (GR-4: PG58 / PG36 = 100: 0).

[Comparative Example 4]
A color filter was obtained in the same manner as in Example 4 except that the green resist was changed from (GR-1) to (GR-5: PG58 / PG36≈30: 70).

[contrast]
A polarizing plate was placed on both sides of the substrate on which the coating film was formed, and the ratio of luminance (Lp) when the polarizing plate was parallel and luminance (Lc) when it was orthogonal, Lp / Lc was calculated as contrast (C). The luminance was measured using a color luminance meter (“BM-5A” manufactured by Topcon Corporation) under the condition of a 2 ° visual field, and “NPF-SEG1224DU” manufactured by Nitto Denko Corporation was used as the polarizing plate. Table 4 below shows the contrast of color filters made from the color resists shown in Table 3 above.

[Production of liquid crystal display devices]
A transparent ITO electrode layer was formed on the obtained color filter, and a polyimide alignment layer was formed thereon. A polarizing plate was formed on the other surface of this glass substrate.

On the other hand, a TFT array and a pixel electrode were formed on one surface of another (second) glass substrate, and a polarizing plate was formed on the other surface. The two glass substrates thus prepared face each other so that the electrode layers face each other, and are aligned using spacer beads while keeping the distance between both substrates constant, and the periphery is left so as to leave an opening for injecting the liquid crystal composition. Sealed with a sealant.

A liquid crystal composition was injected from the opening to seal the opening. The polarizing plate was provided with an optical compensation layer optimized to display a wide viewing angle. The liquid crystal display device thus produced was combined with a backlight unit to obtain a liquid crystal panel.

[Visibility evaluation during black display of liquid crystal display devices]
The produced liquid crystal display device is displayed in black, and the amount of light (orthogonal transmitted light; leaked light) leaking from the normal direction (front) of the liquid crystal panel and an orientation (oblique) 45 ° from the normal direction is visually observed. did. A case where black was observed without light leakage and a case where coloring due to light leakage was observed were evaluated as x. The results are shown in Table 4 below.

  As shown in Example 4, when Rth> 0 for both red and blue, the wavelength of R, G, and B in the phase difference is set by setting Rth (G) = + 10 by controlling the pigment ratio of the green composition. A liquid crystal display device that secures continuity and has good visibility in an oblique direction could be obtained.

  Further, as shown in Example 5, when red indicates Rth (R) <0 and blue indicates Rth (B) <0, Rth (G) =-11 is set by controlling the pigment ratio of the green composition. Thus, Rth (R)> Rth (G)> Rth (B), which has wavelength continuity in each color, and has a well-balanced phase difference in the thickness direction of the red pixel, the green pixel, and the blue pixel. A liquid crystal display device having good visibility was obtained.

  Further, as shown in Example 6, when red indicates Rth (R) <0 and blue indicates Rth (B)> 0, Rth (G) = − 2 by controlling the pigment ratio of the green composition. Thus, a liquid crystal display device in which Rth (R) <Rth (G) <Rth (B) is satisfied, and the phase difference in the thickness direction of the red pixel, the green pixel, and the blue pixel is well balanced and the visibility in the oblique direction is favorable. I was able to get it.

  On the other hand, in Comparative Example 3, the relationship is Rth (R) <Rth (G)> Rth (B), and in Comparative Example 2, the relationship is Rth (R)> Rth (G) <Rth (B). The balance of the phase difference was poor. As a result, color misregistration occurred in black display in an oblique direction, resulting in poor visibility. Further, in Comparative Example 4, the brightness of the green pixel, the contrast in the color filter, and the contrast of the liquid crystal display device were also lowered.

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Black matrix 3R ... Red pixel 3G ... Green pixel 3B ... Blue pixel 4 ... Liquid crystal display device 5, 6 ... Transparent substrate 7 ... TFT Array 8, 12 ... Transparent electrode 9, 13 ... Orientation layer 10, 14 ... Polarizing plate 11 ... Color filter 15 ... Three-wavelength lamp 16 ... Backlight unit.

Claims (3)

C. I. Pigment Green 58 and C.I. I. A green coloring composition for a color filter comprising Pigment Green 36 in a weight ratio of 99: 1 to 35:65, a transparent resin, a solvent, and a photocrosslinking agent. A green colored composition for a color filter, wherein a retardation value Rth in a thickness direction represented by the following formula of a green colored layer formed of the green colored composition is −15 to +15 nm.
Rth = {(Nx + Ny) / 2−Nz} × d
(Where Nx is the refractive index in the x direction in the xy plane of the colored layer, Ny is the refractive index in the y direction in the xy plane of the colored pixel layer, and Nz is the refractive index in the thickness direction of the colored pixel layer, d represents the thickness (nm) of the colored layer.)   A color filter comprising a plurality of color pixels including a red pixel, a green pixel, and a blue pixel on a transparent substrate, wherein the green pixel is formed of the green coloring composition according to claim 1.   A liquid crystal display device comprising the color filter according to claim 2.

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