WO2009101916A1

WO2009101916A1 - Color filter and liquid crystal display device using the same

Info

Publication number: WO2009101916A1
Application number: PCT/JP2009/052162
Authority: WO
Inventors: Takashi Yamauchi; Hidesato Hagiwara; Atsuko Kamada; Yoshiko Ishimaru; Kenji Muneuchi; Noriko Asahi; Satoshi Ohkuma
Original assignee: Toppan Printing Co., Ltd.
Priority date: 2008-02-13
Filing date: 2009-02-09
Publication date: 2009-08-20
Also published as: TW200949310A; CN101952769A

Abstract

Disclosed is a color filter which is used in a liquid crystal display device comprising a white light-emitting backlight having at least a blue LED. The color filter is characterized by comprising at least a red pixel, a green pixel and a blue pixel, and is also characterized in that the green pixel contains a brominated zinc phthalocyanine green pigment.

Description

Color filter and liquid crystal display device using the same

The present invention relates to a color filter having a green pixel containing a brominated zinc phthalocyanine green pigment and a liquid crystal display device using the same.

In recent years, liquid crystal display devices have been rapidly spread in many applications such as television image display devices, computer terminal display devices, mobile terminal liquid crystal display devices for mobile applications, and liquid crystal display devices for in-vehicle use. Competition in display image quality is intensifying.

In addition to television, TV images can now be distributed on computer terminals and mobile terminals, and due to the impact of the start of digital terrestrial broadcasting, all applications have image quality equivalent to or higher than conventional television standards. Therefore, all liquid crystal display devices are required to have high contrast, high speed response, high color reproducibility, high luminance, and the like.

Among them, high color reproducibility and high brightness are characteristics that depend on the backlight light source and color filter provided in the liquid crystal display device. For the backlight, a cold cathode fluorescent tube (CCFL: Cold), which is a conventional light source, is used. Cathode® Fluorescent® Lamp) has a problem that the color purity is lowered due to the sub-peak of the emission spectrum curve of the phosphor. On the other hand, in order to realize high color reproducibility, a technique is employed in which LEDs of three colors of red, green, and blue (light emitting diodes) exhibiting emission spectrum characteristics having no sub-peak are used as a backlight.

The LED has advantages such as excellent response to the CCFL, excellent power consumption, low power consumption, and mercury-free environment.

In color filters, as disclosed in Japanese Patent Application Laid-Open Nos. 2004-163902 and 2006-47975, C.I. which is a brominated copper phthalocyanine green pigment as a colorant for green pixels. I. (Color Index) Pigment Green 36 is known to be used, but a high transmittance is not obtained, and a white LED device in which emission colors are mixed by combining red LED, green LED, and blue LED. In order to improve luminance even when used as a light source, a high transmittance is desired.

In order to improve color reproducibility, the method of increasing the pigment concentration and using a color filter with high color purity has been proposed as the most promising method. However, as the color purity increases, the light passing through the color filter is proposed. There is a problem in that the amount of light is reduced and the luminance is lowered, and it is difficult to achieve both high color reproducibility and high luminance.

An object of the present invention is to provide a color filter capable of improving luminance while maintaining high color reproducibility of a liquid crystal display device when a white LED device is used as a backlight, and a liquid crystal display device using the color filter There is to do.

According to the first aspect of the present invention, there is provided a color filter for use in a liquid crystal display device including a backlight that emits white light having at least a blue LED, and the color filter includes at least a red pixel, a green pixel, and a blue pixel. A color filter is provided in which the green pixel contains a brominated zinc phthalocyanine green pigment.

According to a second aspect of the present invention, the apparatus includes a backlight that emits white light having at least a blue LED, and at least a red pixel, a green pixel, and a blue pixel, and the green pixel contains a brominated zinc phthalicyanine green pigment. There is provided a liquid crystal display device comprising a color filter.

It is a characteristic view which shows the light emission characteristic of the white LED device which mixed red light color by combining red LED, green LED, and blue LED. It is a characteristic view which shows the light emission characteristic of an example of a cold cathode fluorescent tube (CCFL). It is a characteristic view which shows the light emission characteristic of the white LED device which combined blue light and YAG type | system | group fluorescent substance and mixed luminescent color. It is a characteristic view which shows the light emission characteristic of the white LED device which mixed the luminescent color combining blue LED and red and green light emission fluorescent substance. C. I. It is a spectral transmittance curve of Pigment Green 58. It is sectional drawing which shows the outline of the structural example of a liquid crystal display device.

Hereinafter, color filters and liquid crystal display devices according to various embodiments of the present invention will be described in detail.

The color filter according to the first embodiment of the present invention is used for a liquid crystal display device including a white LED device in which a red LED, a green LED, and a blue LED are combined as a backlight to mix emission colors. One example of this white LED device has emission characteristics as shown in FIG. 1, and the emission spectrum characteristics of an example of a cold cathode fluorescent tube (CCFL) used in the conventional liquid crystal display device shown in FIG. Is different.

As shown in FIG. 2, the light emission characteristics of the CCFL have sub-peaks near the blue / green boundary 490 nm and the red / green boundary 580 nm. Therefore, the liquid crystal display device using the CCFL as a backlight has color purity. descend. For high color reproduction of liquid crystal display devices, use high-purity phosphors as CCFL phosphors, or use white LED devices that combine such phosphors and LEDs, and use spectral characteristics of color filters. However, there is a problem that both methods cannot be realized unless the luminance is greatly reduced.

On the other hand, the light emission peak of a white LED device in which red, green, and blue LEDs having emission characteristics as shown in FIG. It was possible to improve the property.

Therefore, in the first embodiment of the present invention, in the liquid crystal display device, a white LED device in which a red LED, a green LED, and a blue LED are combined in the backlight to mix emission colors, and bromination is performed on the green pixel of the color filter. Zinc phthalocyanine green pigments such as C.I. I. By using Pigment Green 58, it was possible to improve luminance while maintaining high color reproducibility.

The color filter according to the second embodiment of the present invention is used in a liquid crystal display device including a white LED device in which a blue LED and a YAG phosphor are combined to mix emission colors as a backlight. An example of this white LED device has emission characteristics as shown in FIG. 3, and the emission spectrum characteristics of an example of a cold cathode fluorescent tube (CCFL) used in the conventional liquid crystal display device shown in FIG. Is different.

Therefore, in the second embodiment of the present invention, in a liquid crystal display device, a white LED device in which a blue LED and a YAG phosphor are combined to mix emission colors is used for a backlight, and a brominated zinc phthalocyanine green pigment is used for a green pixel. For example, C.I. I. By providing a color filter containing Pigment Green 58, it was possible to improve luminance while maintaining high color reproducibility.

The color filter according to the third embodiment of the present invention is used in a liquid crystal display device including a white LED device in which a blue LED and a red / green light emitting phosphor are combined to mix emission colors as a backlight. An example of this white LED device has a light emission characteristic as shown in FIG. 4. What is an emission spectrum characteristic of an example of a cold cathode fluorescent tube (CCFL) used in the conventional liquid crystal display device shown in FIG. Different.

The CCFL having the light emission characteristics as shown in FIG. 2 has reduced color purity due to the presence of sub-peaks near the blue / green boundary 490 nm and the red / green boundary 580 nm. Although it is necessary to change or combine the spectral characteristics of the color filters with high purity phosphors, or to combine them, there is a problem that neither method can be realized unless the luminance is greatly reduced.

On the other hand, the light emission peak of the white LED device, which combines the light emission color by combining the blue LED having the light emission characteristics as shown in FIG. It was possible to improve the property.

Therefore, in the third embodiment of the present invention, in a liquid crystal display device, a white LED device in which a blue LED and a red / green light emitting phosphor are combined in a backlight and a luminescent color is mixed is used, and a brominated zinc phthalocyanine is used in a green pixel. Green pigments such as C.I. I. By providing a color filter containing Pigment Green 58, it was possible to improve luminance while maintaining high color reproducibility.

In the first to third embodiments of the present invention described above, the green pixel has C.I. I. Pigment yellow 150 or C.I. I. Pigment Yellow 138 may be included.

As shown in FIG. 5, brominated zinc phthalocyanine green pigment such as C.I. I. Pigment Green 58 has a transmittance of 490 nm to 630 nm and is a brominated copper phthalocyanine green pigment. I. Since it is higher than the pigment green 36 and the hue is yellowish, the blending ratio of the yellow pigment used for toning can be reduced. As a result, C.I. I. Compared with the case of using Pigment Green 36, it is possible to obtain a bright color filter with less turbidity and excellent color purity.

Green pixels are C.I. I. Pigment Green 58 and C.I. I. When pigment yellow 150 is contained, the weight percentage ratio is [90 to 16]: [10 to 84] when used in the liquid crystal display device according to the first and second embodiments. [92 to 17]: [8 to 83] is desirable.

Also, the green pixel is C.I. I. Pigment Green 58 and C.I. I. When pigment yellow 138 is contained, the weight percentage ratio is [92 to 17]: [8 to 83] when used in the liquid crystal display device according to the first and second embodiments. [94 to 17]: [6 to 83] is desirable.

The color filter according to the first to third embodiments is a color filter including at least a color pixel, a green pixel, and a blue pixel on a transparent substrate, and each of these color pixels includes an organic pigment and a transparent resin as main components. It is a thing. In addition, yellow, magenta, cyan, orange, and the like arranged in the same plane can be applied to each color pixel.

Hereinafter, a method for obtaining the color filter according to these embodiments will be described in detail.

The transparent substrate used for the color filter substrate is preferably one having a certain transmittance with respect to visible light, more preferably one having a transmittance of 80% or more. Generally, 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 used. In the case of using a light shielding pattern, a material obtained by previously attaching a metal thin film such as chromium or a lattice pattern with a light shielding resin on the transparent substrate may be used.

The production method of each color pixel 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, considering high definition, controllability of spectral characteristics, color reproducibility, etc., a transparent photosensitive photosensitive composition in which a pigment is dispersed in a transparent resin together with a photoinitiator and a polymerizable monomer is transparent. A photoresist method is preferred in which a color filter is formed by repeating the process of forming a pixel of one color by forming a coating film on a substrate, pattern exposure to the coating film, and development for each color.

Preparation of the photosensitive coloring composition used for the formation of each color pixel follows, for example, the following method. A pigment serving as a colorant is dispersed in a transparent resin, and then mixed with an appropriate solvent together with a photoinitiator and a polymerizable monomer. There are various methods such as a mill base, three rolls, and a jet mill for dispersing the pigment as the colorant and the transparent resin, and the method is not particularly limited.

Specific examples of organic pigments that can be used in the photosensitive coloring composition used for forming each color pixel are shown by color index numbers.

Examples of red pigments include C.I. I. Pigment Red 254, 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, 255, 264, 272, 279 and the like.

¡As yellow pigment, C.I. I. In addition to Pigment Yellow 150 and PY138, PY1, 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, 137 139, 144, 146, 147, 148, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 1, 1,172,173,174,175,176,177,179,180,181,182,185,187,188,193,194,199,213,214, and the like.

Orange pigment is C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

Examples of green pigments include C.I. I. In addition to “Pigment” Green 58, PG7, 10, 36, 37, and the like can be given.

Examples of blue pigments include C.I. I. Pigment Blue 15, 15: 1, 15: 2,
15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 80 and the like.

As a purple pigment, C.I. I.

Pigment Violet

1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like.

The above pigments can be used alone or in combination of two or more. In combination with the organic pigment, an inorganic pigment may be used in combination in order to ensure good coatability, sensitivity, developability and the like while balancing saturation and lightness. Examples of inorganic pigments include yellow lead, zinc yellow, red pepper, cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green, and other metal oxide powders, metal sulfide powders, and metal powders. Furthermore, for color matching, a dye can be contained within a range that does not lower the heat resistance.

The transparent resin used for the photosensitive coloring composition 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. If necessary, the transparent resin can be used alone or in admixture of two or more monomers or oligomers that are precursors thereof that are cured by irradiation with radiation to produce a transparent resin.

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. , Acrylic resins, alkyd resins, polystyrene, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene, polybutadiene, 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. In addition, linear polymers containing acid anhydrides such as styrene-maleic anhydride copolymer and α-olefin-maleic anhydride copolymer can be obtained from (meth) acrylic compounds having hydroxyl groups such as hydroxyalkyl (meth) acrylate. Half-esterified products are also used.

Examples of polymerizable monomers that can be used as photocrosslinking agents include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and ethylene oxide-modified trimethylolpropane tri (meth). Representative examples include various acrylic esters and methacrylic esters such as acrylate and propylene oxide-modified trimethylolpropane tri (meth) acrylate. These can be used alone or in combination of two or more, and for the purpose of maintaining appropriate photocurability, other polymerizable monomers and oligomers can be mixed and used as necessary.

Other polymerizable 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) a Relate, neopentyl glycol diglycidyl ether di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tricyclodecanyl (meth) acrylate, ester acrylate, (meth) acrylic acid ester of methylolated melamine, epoxy (meth) Acrylic esters and methacrylic esters such as acrylate and urethane acrylate, (meth) acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth) acrylamide, N-hydroxymethyl ( And (meth) acrylamide, N-vinylformamide, acrylonitrile and the like.

These can also be used alone or in combination of two or more.

When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the photosensitive coloring composition. 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, benzophenone compounds such as 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4- Thioxanthone compounds such as diisopropylthioxanthone and 2,4-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 (trichloro) Methyl) -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 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], O- (acetyl) -N- (1-phenyl-2-oxo-2- (4 ′ Oxime ester compounds such as -methoxy-naphthyl) ethylidene) hydroxylamine, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2,4,6-to Phosphine compounds such as methylbenzoyldiphenylphosphine oxide, quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone, borate compounds, carbazole compounds, imidazole compounds, titanocene compounds, etc. are used. . These photopolymerization initiators can be used alone or in combination. The amount of the photopolymerization initiator used is preferably 0.5 to 50% by mass, more preferably 3 to 30% by mass, based on the total solid content of the photosensitive coloring 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 mass, more preferably 3 to 40% by mass based on the total amount of the photopolymerization initiator and the sensitizer.

Furthermore, the photosensitive 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-trimercap -s- triazine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.

If necessary, examples of the thermal crosslinking agent include melamine resin and epoxy 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. 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. Any of these may be used alone or in admixture of two or more.

The photosensitive coloring composition can contain an organic solvent as necessary. 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.

As a blending method of each component as described above, for example, a transparent resin and a pigment are kneaded well using two rolls to form a chip, and then a solvent is added to form a paste. A method of obtaining a photosensitive coloring composition by adding an agent and a sensitizer as required.

A photosensitive coloring composition is applied onto a transparent substrate and prebaked. Spin coating, dip coating, die coating, etc. are usually used as the means for coating, but the coating means is not limited to these as long as it can be coated on a 40 to 60 cm square substrate with a uniform film thickness. Prebaking is preferably performed at 50 to 120 ° C. for about 10 to 20 minutes. The coating film thickness is arbitrary, but considering the spectral transmittance and the like, the film thickness after pre-baking is usually about 2 μm. The substrate on which the photosensitive coloring composition is applied and a coating film is formed is exposed through a photomask. A normal high-pressure mercury lamp or the like may be used as the light source.

Next, develop. An alkaline aqueous solution is used as the developer. Examples of the alkaline aqueous solution include a sodium carbonate aqueous solution, a sodium hydrogen carbonate aqueous solution, a mixed aqueous solution of the two, or a mixture obtained by adding an appropriate surfactant to them. After development, it is washed with water and dried to obtain a pixel of any one color.

A color filter including each color pixel in which the necessary number of colors are combined can be obtained by changing the photosensitive coloring composition and the photomask and repeating the necessary number of steps as described above.

An example of a configuration of a liquid crystal display device including an LED and a color filter as a backlight will be described.

FIG. 6 is a schematic cross-sectional view of the liquid crystal display device according to the first to third embodiments of the present invention. The liquid crystal display device of FIG. 6 is a typical example of a thin film transistor (TFT) driving type liquid crystal display device, and includes

transparent substrates

11 and 21 arranged to face each other, and liquid crystal (LC) is sealed between them. Yes. The liquid crystal display device of the present invention includes liquid crystal such as TN (Twisted Nematic), STN (Super Twisted Nematic), IPS (In-Planes Switching), VA (Vertical Alignment), OCB (Optically Compensated Birefringence), and ferroelectric liquid crystal. Is applicable.

A TFT array 12 is formed on the inner surface of the first transparent substrate 11, and a transparent electrode layer 13 made of, for example, indium-tin-oxide (ITO) is formed thereon. An alignment layer 14 is provided on the transparent electrode layer 13. A polarizing plate 15 is formed on the outer surface of the transparent substrate 11.

On the other hand, the color filter 22 of the present invention is formed on the inner surface of the second transparent substrate 21. Red, green and blue pixels constituting the color filter 22 are separated by a black matrix (not shown). A transparent protective film (not shown) is formed so as to cover the color filter 22 and further, a transparent electrode layer 23 made of, for example, ITO is formed thereon, and the alignment layer 24 covers the transparent electrode layer 23. Is provided. A polarizing plate 25 is formed on the outer surface of the transparent substrate 21. Note that the backlight unit 30 of the present invention is provided below the polarizing plate 15.

Hereinafter, Test Examples 1 to 3 corresponding to the above-described first to third embodiments of the present invention will be shown.

Test example 1
This test example corresponds to the first embodiment of the present invention, and the green color of the color filter in the case of using a white LED device in which a red LED, a green LED, and a blue LED are combined in a backlight to mix emission colors. This shows the effect of using brominated zinc phthalicyanine green pigment in the pixel.

(Synthesis example of acrylic resin)
70 parts of cyclohexanone was placed in a reaction vessel, heated to 80 ° C. while injecting nitrogen gas into the vessel, and 12.3 parts of benzyl methacrylate, 4.6 parts of 2-hydroxyethyl methacrylate, 5. 3 parts, a mixture of 7.4 parts of paracumylphenol ethylene oxide modified acrylate (“Aronix M110” manufactured by Toa Gosei Co., Ltd.) and 0.4 part of 2,2,2′-azobisisobutyronitrile was added dropwise over 2 hours. The polymerization reaction was carried out.

After completion of the dropwise addition, the mixture was further reacted at 80 ° C. for 3 hours. Then, 0.2 part by weight of azobisisobutyronitrile dissolved in 10 parts by weight of cyclohexanone was added, and the reaction was further continued at 80 ° C. for 1 hour. A resin copolymer solution was obtained. After cooling to room temperature, about 2 g of acrylic resin solution was sampled and heated and dried at 180 ° C. for 20 minutes to measure the non-volatile content. Cyclohexanone was adjusted so that the non-volatile content was 20% by weight in the previously synthesized acrylic resin solution. Was added to prepare an acrylic resin solution. The weight average molecular weight Mw of the obtained acrylic resin was 20000 kg.

(Preparation of pigment dispersion paste)
As shown in Table 1 below, the pigment dispersion paste is prepared by uniformly stirring and mixing a pigment, an acrylic resin, and propylene glycol monomethyl ether acetate (hereinafter referred to as PGMEA), and using a zirconia bead having a diameter of 1.0 mm in a sand mill. For 3 hours, and then filtered through a 5 μm filter. All composition ratios are weight ratios. The acrylic resin used was synthesized in the above synthesis example.

(Preparation of photosensitive coloring composition)
As shown in Tables 2-5 below, each component was prepared in the proportions shown in Tables 2-5 below, stirred and mixed with a stirrer until each component was completely dissolved, and filtered through a 1 μm filter. Photosensitive coloring compositions R-1, G-1 to G20, and B-1 were prepared.

The red photosensitive coloring composition used for forming the red pixel is a red photosensitive coloring composition having a pigment ratio (weight percentage) as shown in Table 6 below (in Table 2, R-1 is [54.25: 4.08] = [93: 7]).

The green photosensitive coloring compositions used for forming the green pixels are the green photosensitive coloring compositions G-1 to G-20 having pigment ratios (weight percentages) as shown in Tables 7 and 8 below.

Moreover, the blue photosensitive coloring composition used for formation of a blue pixel is a blue photosensitive coloring composition of a pigment ratio (weight percentage) as shown in Table 9 below.

With respect to the photosensitive coloring composition having the above pigment ratio, the red pixel is x = 0.640, the green pixel is y = 0.600, and the blue pixel is y = 0.600 in the chromaticity coordinates xy of the CIE1931XYZ color system. A three-color filter was prepared by adjusting the combinations shown in the following examples and comparative examples. The adjustment chromaticity value is based on the EBU standard value, which is a broadcast standard, but is not limited to this range.

The red photosensitive coloring composition shows R-1 shown in Table 2 (Table 6), the blue photosensitive coloring composition shows B-1 shown in Table 5 (Table 9), and the green photosensitive coloring composition shows the above. Using G-1 to G-10 shown in Tables 2 and 3 (Table 7), a three-color filter was produced with the above-mentioned designated chromaticity aim.

Examples 1 to 10 are combinations of backlights having a white LED device in which these color filters are combined with red LEDs, green LEDs, and blue LEDs to mix emission colors.

The red photosensitive coloring composition is R-1 shown in Table 2 (Table 6), the blue photosensitive coloring composition is B-1 shown in Table 5 (Table 9), and the green photosensitive coloring composition. Used G-11 to G-20 shown in Tables 4 and 5 (Table 8), and a three-color filter was prepared with the above-mentioned chromaticity aim.

Comparative Examples 1 to 10 are combinations of backlights each including a white LED device in which these color filters are combined with red LEDs, green LEDs, and blue LEDs to mix emission colors.

〔Evaluation item〕
(brightness)
The lightness (G−Y) of the green pixel and the lightness (W−Y) in white display as a color filter are calculated by C.I. I. Pigment Green 58 (PG58) and C.I. I. In the case of using Pigment Green 36 (PG36), the brighter one was marked with ◯ and the lower one with x.

In this comparison method, C.I. I. A color filter according to an embodiment using Pigment Green 58; I. The color filter according to the comparative example using the pigment green 36 is prepared by adjusting the xy chromaticity values in the CIE1931 XYZ display system to the same value, and then the xy chromaticity values are adjusted to the same value. The numbers of the example and the comparative example were aligned (for example, Example 1 and Comparative Example 1 correspond), and the values of (GY) and (WY) were compared and judged.

〔Evaluation results〕
Table 10 shows the evaluation results of Examples 1 to 10, and Table 11 shows the results of Comparative Examples 1 to 10.

The chromaticity values in Tables 10 and 11 are xy chromaticity and Y (lightness) in the CIE1931 XYZ color system.

From the results of Tables 10 and 11, the following is clear. That is, the lightness (G−Y) of the green pixel and the lightness (W−Y) in white display as a color filter are set as C.I. I. Pigment Green 58 (PG58) (Examples 1 to 10), C.I. I. As a result of comparing Pigment Green 36 (PG36) (Comparative Examples 1 to 10) with the same numbers 1 to 10, the C.I. I. When the pigment green 58 (PG58) is used (Examples 1 to 10), it is high and it can be seen that high luminance is realized.

Test example 2
This test example corresponds to the second embodiment of the present invention, and a green pixel of a color filter when a white LED device in which a blue LED and a YAG phosphor are combined to mix emission colors is used as a backlight. This shows the effect of using brominated zinc phthalocyanine green pigment.

(Synthesis example of acrylic resin)
In the same manner as in Test Example 1, an acrylic resin solution containing an acrylic resin having a weight average molecular weight Mw of 20000 was prepared.

(Preparation of pigment dispersion paste)
In the same manner as in Test Example 1, a pigment dispersion paste as shown in Table 1 was prepared.

(Preparation of photosensitive coloring composition)
Each component was prepared in the proportions shown in Tables 12 to 15 below, stirred and mixed with a stirrer until each component was completely dissolved, and filtered through a 1 μm filter, as shown in Tables 12 to 15 below. Coloring compositions R-2, G-21 to G40, and B-2 were prepared.

The red photosensitive coloring composition used for forming the red pixel is a red photosensitive coloring composition having a pigment ratio (weight percentage) as shown in Table 16 below (in Table 12, R-1 is [54.25]. : 4.08] = [93: 7]).

The green photosensitive coloring compositions used for forming the green pixels are the green photosensitive coloring compositions G-21 to G-40 having pigment ratios (weight percentages) as shown in Tables 17 and 18 below.

Moreover, the blue photosensitive coloring composition used for formation of a blue pixel is a blue photosensitive coloring composition of a pigment ratio (weight percentage) as shown in Table 19 below.

The red photosensitive coloring composition has R-2 shown in Table 12 (Table 16), the blue photosensitive coloring composition has B-2 shown in Table 15 (Table 19), and the green photosensitive coloring composition has the above. Using G-21 to G-30 shown in Tables 12 and 13 (Table 17), a three-color color filter was produced with the above-mentioned designated chromaticity aim.

Examples 11 to 20 are combinations of these color filters and a backlight having a white LED device in which a luminescent color is mixed by combining a blue LED and a YAG phosphor.

The red photosensitive coloring composition is R-2 shown in Table 12 (Table 16), the blue photosensitive coloring composition is B-2 shown in Table 15 (Table 19), and the green photosensitive coloring composition. Used G-31 to G-40 shown in Tables 14 and 15 (Table 18) to produce a three-color filter with the above-mentioned specified chromaticity aim.

Comparative examples 11 to 20 are combinations of these color filters and backlights having a white LED device in which light emission colors are mixed by combining blue LEDs and YAG phosphors.

〔Evaluation results〕
The evaluation results of Examples 11 to 20 are shown in Table 20 below, and the results of Comparative Examples 11 to 20 are shown in Table 21 below.

The chromaticity values in Tables 20 and 21 below are xy chromaticity and Y (lightness) in the CIE1931 XYZ color system.

From the results in Tables 20 and 21 above, the following is clear. That is, the lightness (G−Y) of the green pixel and the lightness (W−Y) in white display as a color filter are set as C.I. I. Pigment Green 58 (PG58) (Examples 11 to 20), C.I. I. As a result of comparing Pigment Green 36 (PG36) (Comparative Examples 11 to 20) with the same numbers 11 to 20, C.I. I. It can be seen that when the pigment green 58 (PG58) is used (Examples 11 to 20), the luminance is high and high luminance is realized.

Test example 3
This test example corresponds to the third embodiment of the present invention, and is a color filter when a white LED device in which a blue LED and a red / green light emitting phosphor are combined to mix emission colors is used as a backlight. This shows the effect of using a brominated zinc phthalocyanine green pigment for a green pixel.

(Preparation of photosensitive coloring composition)
Each component was prepared in the proportions shown in the following Tables 22 to 25, stirred and mixed with a stirrer until each component was completely dissolved, and filtered through a 1 μm filter, as shown in Tables 22 to 25 below. Coloring compositions R-3, G-41 to G60, and B-3 were prepared.

The red photosensitive coloring composition used for forming the red pixel is a red photosensitive coloring composition having a pigment ratio (weight percentage) as shown in Table 26 below (in Table 22, R-3 is [54. 25: 4.08] = [93: 7]).

The green photosensitive coloring compositions used for forming the green pixels are the green photosensitive coloring compositions G-41 to G-60 having pigment ratios (weight percentages) as shown in Tables 27 and 28 below.

Moreover, the blue photosensitive coloring composition used for formation of a blue pixel is a blue photosensitive coloring composition of a pigment ratio (weight percentage) as shown in Table 29 below.

The red photosensitive coloring composition has R-3 shown in Table 22 (Table 26), the blue photosensitive coloring composition has B-3 shown in Table 25 (Table 29), and the green photosensitive coloring composition has the above. Using G-41 to G-50 shown in Tables 22 and 23 (Table 17), a three-color filter was produced with the above-mentioned designated chromaticity aim.

Examples 21 to 30 are combinations of these color filters and backlights having a white LED device in which light emission colors are mixed by combining blue LEDs and red / green light emitting phosphors.

The red photosensitive coloring composition is R-3 shown in Table 22 (Table 26), the blue photosensitive coloring composition is B-3 shown in Table 25 (Table 29), and the green photosensitive coloring composition. Used G-51 to G-60 shown in Tables 24 and 25 (Table 28), and produced a three-color filter with the above-mentioned specified chromaticity aim.

Comparative Examples 21 to 30 are combinations of these color filters and backlights having a white LED device in which light emission colors are mixed by combining blue LEDs and red / green light emitting phosphors.

〔Evaluation results〕
The evaluation results of Examples 21 to 30 are shown in Table 30 below, and the results of Comparative Examples 21 to 30 are shown in Table 31 below.

The chromaticity values in the following Tables 30 and 31 are xy chromaticity and Y (lightness) in the CIE1931 XYZ color system.

From the results in Tables 30 and 31 above, the following is clear. That is, the lightness (G−Y) of the green pixel and the lightness (W−Y) in white display as a color filter are set as C.I. I. Pigment Green 58 (PG58) (Examples 21 to 30), C.I. I. As a result of comparing Pigment Green 36 (PG36) (Comparative Examples 21 to 30) with the same numbers 21 to 30, C.I. I. It can be seen that when the pigment green 58 (PG58) is used (Examples 21 to 30), high luminance is realized.

Claims

A color filter used in a liquid crystal display device including a backlight that emits white light having at least a blue LED, the color filter including at least a red pixel, a green pixel, and a blue pixel, wherein the green pixel is brominated A color filter comprising a zinc phthalocyanine green pigment.
The color filter according to claim 1, wherein the backlight is a white LED device in which a red LED, a green LED, and a blue LED are combined to mix emission colors.
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 2, comprising Pigment Yellow 150.
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 2, comprising Pigment Yellow 138.
The color filter according to claim 1, wherein the backlight is a white LED device in which a blue LED and a YAG phosphor are combined to mix emission colors.
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 5, comprising Pigment Yellow 150.
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 5, comprising Pigment Yellow 138.
C. I. Pigment Green 58 and C.I. I. The color filter according to claim 3 or 6, wherein the pigment yellow 150 has a weight percentage ratio of [90 to 16]: [10 to 84].
C. I. Pigment Green 58 and C.I. I. The color filter according to claim 4 or 7, wherein the weight percentage ratio of Pigment Yellow 138 is [92 to 17]: [8 to 83].
2. The color filter according to claim 1, wherein the backlight is a white LED device in which a blue LED and a red / green light emitting phosphor are combined to mix emission colors.
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 10, comprising Pigment Yellow 150.
C. I. Pigment Green 58 and C.I. I. The color filter according to claim 11, wherein the weight percentage ratio of CI Pigment Yellow 150 is [92 to 17]: [8 to 83].
The green pixel is C.I. I. Pigment Green 58 and C.I. I. The color filter according to claim 10, comprising Pigment Yellow 138.
C. I. Pigment Green 58 and C.I. I. 14. The color filter according to claim 13, wherein the weight percentage ratio of Pigment Yellow 138 is [94-17]: [6-83].
When the brominated zinc phthalocyanine green pigment was replaced with a brominated copper phthalocyanine green pigment and compared with a color filter in which the xy chromaticity values in the CIE1931 XYZ display system were toned identically, the brightness (G− 2. The color filter according to claim 1, wherein the brightness (WY) in white display as Y) and the color filter is a high value.
A backlight that emits white light having at least a blue LED, and a color filter including at least a red pixel, a green pixel, and a blue pixel, the green pixel containing a brominated zinc phthalocyanine green pigment. Liquid crystal display device.