JP2009251000A - Color filter, and transflective liquid crystal display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter capable of providing a transflective liquid crystal display for a mobile terminal having high color reproducibility and sufficient lightness, without providing a reflecting area and a transmissive area individually within one pixel, and the transflective liquid crystal display of performance hereinbefore. <P>SOLUTION: The color filter has the transmissive area for transmission display and the reflecting area within one pixel, the color filter is constituted of red color, green color and blue color pixels, a spectral transmittance of the green color pixel at 600 nm of wavelength is within a range of 55%≤T<SB>G600</SB>≤85%, a spectral transmittance at 650 nm of wavelength is within a range of 15%≤T<SB>G650</SB>≤35%, a white color LED color-mixed by combining red color, green color and blue color LEDs is used as a backlight. Each pixel has ≥80% of transmittance in a peak wavelength of an emission spectrum from each corresponding LED. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color filter and a transflective liquid crystal display device, and in particular, a color filter that enables a transflective liquid crystal display device having high color reproducibility and sufficient brightness required for a portable terminal, And a transflective liquid crystal display device having the above-mentioned performance.

  Color liquid crystal display devices are widely spread from large-sized devices such as televisions and display devices for computer terminals to small-sized devices such as notebook PCs, mobile phones, and display devices for digital cameras. In particular, liquid crystal display devices are used in most display devices mounted on small devices (portable terminals) such as mobile phones and digital cameras, taking advantage of thinness, light weight, and low power consumption. However, these small devices are often used outdoors, and a transmissive liquid crystal display device using a backlight is perceived to be dark when the ambient light is strong, resulting in poor visibility. Yes.

  In order to solve this problem, a transflective liquid crystal display device has been devised in which a reflective film is provided on a part of a pixel of a transmissive liquid crystal display device so that a half is a transmissive type and a half is a reflective type (non-patent document). 1). In a transflective liquid crystal display device, a transmissive area that uses a backlight and a reflective area that uses ambient ambient light coexist in one pixel, but in the transmissive area, the light from the backlight passes through the color filter only once. On the other hand, since ambient light passes through the color filter twice in the reflection area, if a color filter having the same color density as that of the transmission area is used, the color becomes too dark, resulting in a dark display.

In order to solve this problem, a method of providing an opening in the pixel portion of the color filter in the reflective region, or as disclosed in Patent Document 1, a reflective region and a transmissive region are individually provided in one pixel, A method to make the color lighter has been devised. However, any of these methods increases the manufacturing process of the color filter, which increases the cost.
JP 2001-183646 A JP 2004-184737 A "Fine Process Technology Japan '99, Special Technology Seminar Text A5", July 2, 1998

In recent years, white LEDs (white LEDs in which blue LEDs and yellow phosphors are mixed and mixed) are exclusively used as light sources for backlights used in portable terminals, which are advantageous for downsizing and weight reduction. The white LED is about 60% color reproduction range in the NTSC ratio for the peak is wide of medium and long wavelength, a tristimulus value Y 30 about the standard light D _65.
This mobile terminal is also required to have high color reproducibility, high color reproducibility in indoor transmissive display (70% or more by NTSC ratio), and sufficient brightness in outdoor reflective display (tristimulus values). Y is 35 or more).

The conflicting demands of improving color reproducibility in transmissive display and ensuring sufficient brightness in reflective display are that the transmissive region is made thick by using a method in which the reflective region and transmissive region are separately provided in the one pixel. The reflection region is achieved by making the color darker and the reflection region lighter. However, in the conventional white light source LED of the backlight (white LED mixed with a combination of blue LED and yellow phosphor), the transmissive region becomes conspicuous in order to obtain high color reproducibility. Therefore, sufficient brightness cannot be obtained in any of the reflection areas.

In order to solve this problem, Patent Document 2 uses, as a light source, a three-wavelength LED having a narrow peak at a long wavelength instead of a white LED (a white LED obtained by combining a blue LED and a yellow phosphor). A technique of combining this light source with a color filter provided with a reflection region and a transmission region separately is disclosed.
However, the color filter used here is a color filter in which a reflective region and a transmissive region are separately provided in one pixel, which not only increases the cost of manufacturing the color filter but also increases the cost within one pixel. Since the reflection area and the transmission area are provided separately, it is difficult to achieve high definition.
In Patent Document 2, the three-wavelength LED is a white LED in which a UV-LED and an RGB three-color phosphor are combined and mixed, and a white LED in which a red LED, a green LED, and a blue LED are combined. Point to.

  The present invention has been made in order to solve the above problems, and is a color filter used in a transflective liquid crystal display device using a white LED, which is a combination of red, green, and blue LEDs, as a backlight. In addition, a color filter that enables a transflective liquid crystal display device having high color reproducibility and sufficient brightness required for a portable terminal without separately providing a reflective region and a transmissive region in one pixel, and the above It is an object to provide a transflective liquid crystal display device having performance.

The present invention is a color filter used in a transflective liquid crystal display device using a white LED, which is a color mixture of red LED, green LED, and blue LED, as a backlight, and the color filter includes a red pixel, a green pixel, and a blue pixel. The spectral transmittance of the green pixel is such that the transmittance at a wavelength of 600 nm (T _G600 ) is [55% ≦ T _G600 ≦ 85%], and the transmittance at a wavelength of 650 nm (T _G650 ) is [15]. % ≦ T _G650 ≦ 35%].

  Further, the present invention provides the color filter according to the above invention, wherein the red pixel corresponding to the red LED, the green pixel corresponding to the green LED, and the blue pixel corresponding to the blue LED have peak wavelengths of the emission spectrum of each color LED. The color filter has a transmittance of 80% or more for each color pixel.

Further, the present invention provides a color filter according to claim 1 or claim 2, wherein the tristimulus value Y of the white point of the standard light D ₆₅ (W) is not less than 35, the color reproduction in combination with the backlight The color filter is characterized in that the range is NTSC ratio of 70% or more on the xy chromaticity diagram of the CIE1931XYZ color system.

  Moreover, this invention is the transflective liquid crystal display device using the color filter as described in any one of Claims 1-3.

The present invention relates to a color filter for a transflective liquid crystal display device having a transmissive region for transmissive display using transmitted light from a backlight in one pixel and a reflective region for reflective display using peripheral ambient light. The color filter is composed of a red pixel, a green pixel, and a blue pixel. The spectral transmittance of the green pixel is a transmittance (T _G600 ) at a wavelength of 600 nm: 55% ≦ T _G600 ≦ 85%, At 650 nm, the transmittance (T _G650 ) is a color filter with 15% ≦ T _G650 ≦ 35%. Therefore, when a white LED mixed with a combination of a red LED, a green LED, and a seven-color LED is used as a backlight. In addition, the color filter enables a transflective liquid crystal display device having high color reproducibility required for a portable terminal and sufficient brightness.
Further, the present invention provides a transflective liquid crystal display device having the above performance.

The color filter and transflective liquid crystal display device of the present invention will be described in detail below based on the embodiments.
As a result of studying to solve the above problem, the present inventor has improved the color reproducibility of transmissive display without using a color filter having a complicated structure in which a transmissive region and a reflective region are separately provided, and It has been found that a transflective liquid crystal display device with a bright reflective display is possible.

The transflective liquid crystal display device of the present invention includes a liquid crystal layer having a dimming function by applying voltage at least, a pair of substrates disposed opposite to each other with the liquid crystal layer interposed therebetween, and surrounding ambient light as a light source. A reflection means to be used and a backlight are provided, and a transmission region that transmits light from the light source of the backlight and a reflection region that reflects external light are provided in one pixel. The transmission region and the reflection region in one pixel are not provided separately.
By providing both the reflecting means and the backlight light source, it is possible to obtain a good display even in an outdoor environment where the intensity of ambient external light is stronger than the light source of the backlight or in a relatively dim indoor environment. Further, when the reflecting means is disposed on the surface of the substrate on the side opposite to the observer in contact with the liquid crystal, it is possible to obtain a clear display free from blurring or color mixing of the image due to parallax.

The color filter of the present invention has a transmittance (T _G600 ) at a measurement wavelength of 600 nm of 55% ≦ T _G600 ≦ 85% in the spectral transmittance of a green pixel in order to obtain sufficient brightness in reflective display. The transmittance (T _G650 ) at a measurement wavelength of 650 nm is preferably 15% ≦ T _G650 ≦ 35%. More preferably, the transmittance (T _G600 ) at a measurement wavelength of 600 nm is 60% ≦ T _G600 ≦ 80%, and the transmittance (T _G650 ) at a measurement wavelength of 650 nm is 20% ≦ T _G650 ≦ 30%. is there.

When _TG600 is less than 55% or _TG650 is less than 15%, ambient ambient light is not sufficiently transmitted, resulting in dark reflection display. On the other hand, when _TG600 is greater than 85%, the half-value width of the transmission spectrum of the green pixel becomes too wide and the color reproduction range becomes narrow.
On the other hand, when _TG650 is larger than 35%, the yellowishness of the green pixel becomes too strong, resulting in a yellowish display. However, the presence of a certain amount of light transmission in the red region such as T _G600 and T _G650 contributes to a bright screen display.

In order for _{TG 600} and _{TG 650} to fall within the above range, the ratio of the green pigment to the yellow pigment used for the green pixel is important. For example, when CIPgment Green 36 is used as the green pigment and CIPgment Yellow 150 is used as the yellow pigment, the Green / Yellow ratio is preferably in the range of 0.42 to 1.00, more preferably, by the weight ratio of the pigment. It is in the range of 0.52 to 0.83. When CIPgment Green 36 is used as a green pigment and CIPgment Yellow 138 is used as a yellow pigment, the Green / Yellow ratio is preferably in the range of 0.33 to 0.67, more preferably, by the weight ratio of the pigment. It is in the range of 0.42 to 0.55.

  Furthermore, at the peak wavelengths of the emission spectra of the red LED, green LED, and blue LED of the backlight, the transmittance of each of the red, green, and blue pixels of the color filter is 80% or more. In addition to maintaining the brightness of the screen of the transflective liquid crystal display device installed, it is also involved in improving the vividness (saturation) of color display.

In addition, since the color filter of the present invention has a high transmittance of the tristimulus value Y of the white point (W) measured using the standard light D ₆₅ of 35 or more, bright reflection display is possible. In order to obtain a brighter reflective display, Y is preferably 36.5 or more, and more preferably 38 or more. In addition, the transflective liquid crystal display device of the present invention uses a white LED obtained by combining red, green, and blue LEDs with high color reproducibility as a light source of a backlight, and a color filter and the backlight. When the color reproduction range on the xy chromaticity diagram of the CIE1931XYZ color system measured in combination with light is 70% or more in NTSC ratio, it is possible to obtain high color reproducibility of transmissive display.

The visibility of the liquid crystal display device can be compared by displaying a test pattern.
Examples of the test pattern include a full field color bar, an EIA color bar, and an SMPTE color bar, but are not particularly limited. In the liquid crystal display device using the color filter of the present invention and the above backlight, the color reproduction range on the xy chromaticity diagram of the XYZ color system is 70% or more in NTSC ratio, so the reproducibility of each color of the color bar is high. It is high.
On the other hand, in an outdoor environment where the intensity of external light is strong, the tristimulus value Y of the white point (W) is 35 or more and the transmittance of the colored layer is high, so the color bar display is bright and good. Further, in the spectral transmittance of the green pixel, the transmittance at the measurement wavelength of 600 nm (T _G600 ) is 55% ≦ T _G600 ≦ 85%, and the transmittance at 650 nm (T _G650 ) is 15% ≦ T _G650 ≦ 35%. Therefore, the color reproducibility is high and the display of the color bar is easy to identify.

  In the transflective liquid crystal display device of the present invention, the substrate on which the reflecting means is formed may be either a color filter side substrate or a substrate facing the color filter. The reflection means is preferably used in the case where a transmissive region is formed so that the backlight is transmitted through a part of the metal film. When the reflective film is formed on the color filter side, the reflective film is formed in the pixel area where the color material is formed, and the reflective film is formed in the pixel area. The non-existing area becomes the transmission area. When the reflective film is formed on the substrate facing the color filter, the color filter pixel area corresponding to the reflective film forming area of the counter substrate becomes the reflective area, and the reflective film is not formed on the area of the substrate. The corresponding color filter pixel area becomes the transmission area.

  The formation of the color filter is not limited to the transparent substrate side such as glass or polymer film, but can also be performed on the drive element side substrate. The pattern shape of the color filter includes a stripe shape and an island shape, but is not particularly limited. In addition, a fixed spacer may be disposed on the color filter as necessary.

Hereinafter, a method for obtaining a color filter included in the transflective liquid crystal display device will be described in detail.
The transparent substrate used for the substrate of the color filter preferably has a certain degree of transmittance with respect to visible light, and more preferably has 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, it is only necessary to use a metal thin film such as chromium or a pattern made of a light shielding resin previously attached to the transparent substrate by a known method.

  The method for producing 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 formation of each color pixel follows the following method, for example. 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, H.264, 272, 279 and the like.

  Examples of yellow pigments include 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, 17 1,172,173,174,175,176,177,179,180,181,182,185,187,188,193,194,199,213,214 etc. are mentioned.

Examples of orange pigments include 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.
Examples of purple pigments include C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50, and the like.

  The 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 blue, 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 a photocrosslinking agent 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) acrylate , 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) acrylate , Various acrylates and methacrylates such as 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. Also about these, it can use individually or in mixture of 2 or more types.

  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, 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, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 9,10-phenanthrenequinone, camphorquinone, ethyl anthraquino Quinone compounds such as borate compounds, carbazole 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 mass, more preferably 3 to 30% by mass, 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 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-trimercapto-s-to Azine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination.

Moreover, as needed, as a thermal crosslinking agent, a melamine resin, an epoxy resin, etc. are mentioned, for example. 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.

  The photosensitive coloring composition can contain a storage stabilizer in order to stabilize the viscosity of the composition with time, and an adhesion improver such as a silane coupling agent in order to improve the adhesion to the transparent substrate. Can also be included. Examples of storage stabilizers include quaternary ammonium chlorides such as benzyltrimethyl chloride and diethylhydroxyamine, organic acids such as lactic acid and oxalic acid, and methyl ethers thereof, t-butylpyrocatechol, tetraethylphosphine, and tetraphenylphosphine. Organic phosphines, phosphites and the like can be mentioned.

  Examples of the silane coupling agent include vinyl silanes such as vinyltris (β-methoxyethoxy) silane, vinylethoxysilane, 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) methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and other epoxysilanes, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N- β (aminoethyl) γ-aminopropyltri Ethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N- Examples include aminosilanes such as phenyl-γ-aminopropyltriethoxysilane, and thiosilanes such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane.

The coloring composition can be prepared in the form of gravure offset printing ink, waterless offset printing ink, silk screen printing ink, ink jet ink, solvent development type or alkali development type color resist. The colored resist is obtained by dispersing the pigment in a composition containing a thermoplastic resin, a thermosetting resin or an active energy ray curable resin, a monomer, a photopolymerization initiator, and the solvent. is there. The pigments are preferably contained in a proportion of 5 to 70% by weight in total based on the total solid content of the colored composition (100% by weight). More preferably, it is contained in a proportion of 20 to 50% by weight, and the remainder consists essentially of a resinous binder provided by a pigment carrier. The colored coating solution composition is a coarse particle having a size of 5 μm or more, preferably a coarse particle having a size of 1 μm or more, more preferably a coarse particle having a size of 0.5 μm or more, more preferably by means of centrifugation, a sintered filter, a membrane filter, or the like. It is preferable to remove particles of 0.2 μm or more and mixed dust.

The color filter of the present invention comprises one or a plurality of colored pixels formed on the transparent substrate using the colored composition of the present invention. The color filter of the present invention usually further comprises a green pixel formed using the colored composition according to the present invention, a red pixel formed using a known colored composition, and a blue pixel. Furthermore, cyan, yellow, and magenta colored pixels formed using a known coloring composition can be provided as necessary.
Further, the cyan colored pixel can be formed using the colored composition of the present invention. As the transparent substrate, glass plates such as soda lime glass, low alkali borosilicate glass and non-alkali alumino borosilicate glass, and resin plates such as polycarbonate, polymethyl methacrylate, and polyethylene terephthalate are used.
Further, a transparent electrode made of indium oxide, tin oxide, or the like may be formed on the surface of the glass plate or the resin plate for driving the liquid crystal after the liquid crystal panel is formed.

  The colored pixels for each color can be formed by, for example, a printing method, an inkjet method, a photolithography method, or the like. 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.

As a method of manufacturing a color filter using an inkjet method, a method of forming a colored pixel by forming a black matrix on a glass substrate and applying ink to the opening of the black matrix using an inkjet printing apparatus has been proposed. ing. Further, in this method, the black matrix contains a water repellent such as a fluorine compound or a silicon compound so that the ink is satisfactorily filled into the predetermined opening and the mixed color in which the ink is mixed between adjacent colored pixels does not occur. You may not.
As an apparatus used for inkjet, there are a piezo conversion method and a heat conversion method depending on a difference in an ink discharge method. Also. The ink atomization frequency of the ink jet apparatus is about 5 to 100 kHz. Further, the nozzle diameter of the ink jet apparatus is desirably about 5 to 80 μm. In addition, an ink jet apparatus in which a plurality of heads are arranged and about 60 to 500 nozzles are incorporated in one head is used. After patterning by the inkjet method, a colored pixel is formed by heat processing using a convection oven, an IR oven, a hot plate, or the like. According to the inkjet method, since a plurality of colors can be applied simultaneously, a color filter can be manufactured at a low cost by a simple process.

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

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

  The color filter of the present invention can be produced by an electrodeposition method, a transfer method or the like in addition to the above method. The electrodeposition method uses a transparent conductive film formed on a transparent substrate, and a method for producing a color filter by electrodepositing colored pixels of each color on the transparent conductive film by electrophoresis of colloidal particles. It is. The transfer method is a method in which colored pixels are formed in advance on the surface of a peelable transfer base sheet or transfer cylinder, and the colored pixels are transferred to a desired transparent substrate.

If a black matrix is formed in advance before forming colored pixels of each color on a transparent substrate or a reflective substrate, the contrast of the liquid crystal display panel can be further increased. As the black matrix, an inorganic film such as chromium, a chromium / chromium oxide multilayer film, titanium nitride, or a resin film in which a light shielding agent is dispersed may be used. In addition, a thin film transistor (TFT) may be formed in advance on the transparent substrate or the reflective substrate, and then colored pixels may be formed. By forming colored pixels on the TFT substrate, the aperture ratio of the liquid crystal display panel can be increased and the luminance can be improved.
On the color filter of the present invention, an overcoat film, a columnar spacer, a transparent conductive film, a liquid crystal alignment film, and the like are formed as necessary.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively. The symbol of the pigment indicates a color index number. For example, “PR254” represents “CI PigmentRED254” and “PY150” represents “CI Pigment Yellow 150”.

[Backlight device]
Nichia Co., Ltd .: Two-wavelength white LED (white LED mixed with blue LED and yellow phosphor) “NSSW440” is placed on the substrate on which the wiring is patterned, and the driver IC for driving Attached. A backlight was created by combining a reflector, a light guide plate, a diffuser plate, and a prism sheet. Moreover, the backlight was similarly produced using 3 color LED (white LED which combined red LED, green LED, and blue LED, and was mixed). The spectral spectra of the manufactured backlight are shown in FIGS. 1 and 2, respectively.

[Preparation of acrylic resin solution]
The preparation of the acrylic resin solution used in Examples and Comparative Examples will be described. The molecular weight of the resin is a weight average molecular weight in terms of polystyrene measured by GPC (gel permeation chromatography).

370 parts of cyclohexanone was placed in a reaction vessel, heated to 80 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added dropwise at the same temperature over 1 hour to carry out a polymerization reaction.

Methacrylic acid 20.0 parts Methyl methacrylate 10.0 parts n-Butyl methacrylate 35.0 parts 2-Hydroxyethyl methacrylate 15.0 parts 2,2'-Azobisisobutyronitrile 4.0 parts Paracmylphenol ethylene oxide modification Acrylate (Toa Gosei Co., Ltd .: “Aronix M110”) 20.0 parts

After completion of the dropwise addition, the mixture was further reacted at 80 ° C. for 3 hours, and then 1.0 part of azobisisobutyronitrile dissolved in 50 parts of PGMAc was added, and the reaction was further continued at 80 ° C. for 1 hour to obtain an acrylic resin. Solution was obtained. The weight average molecular weight of the acrylic resin was about 40,000.
After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20% by weight. To prepare an acrylic resin solution.

[Coloring composition]
The following were used for the coloring agent for coloring the coloring composition used for color filter preparation.

Red pigment: C.I. I. Pigment Red 254 (“Ilgar Forred B-CF” manufactured by Ciba Specialty Chemicals), and C.I. I. Pigment Red 177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals)
Green pigment: C.I. I. Pigment Green 36 (“Lionol Green 6YK” manufactured by Toyo Ink Co., Ltd.), and C.I. I. Pigment Yellow 150 (Bayer's “Funcheon First Yellow Y-5688”)
Blue pigment: C.I. I. Pigment Blue 15 (“Rionol Blue ES” manufactured by Toyo Ink Manufacturing Co., Ltd.) C.I. I. Pigment Violet 23 (manufactured by BASF “Paliogen Violet 5890”)
Red, green and blue colored compositions were prepared using the respective pigments.

[Preparation of pigment dispersion]
The mixture having the composition shown in Table 1 was uniformly stirred and mixed, and then dispersed with an Eiger mill for 2 hours using zirconia beads having a diameter of 0.1 mm, and then filtered with a 5 μm filter to prepare a pigment dispersion.

分散剤 ： アクリル系分散剤 （ビックケミー社製 「ＢＹＫ−２００１」）
有機溶剤 ： シクロヘキサノン
［感光性着色組成物の調製］
次いで、表２に示す組成（重量比）の混合物を均一になるように攪拌混合した後、１μｍのフィルタで濾過して感光性着色組成物を得た。

Dispersant: Acrylic dispersant (BYK-2001 manufactured by Big Chemie)
Organic solvent: cyclohexanone [Preparation of photosensitive coloring composition]
Next, a mixture having a composition (weight ratio) shown in Table 2 was stirred and mixed so as to be uniform, and then filtered through a 1 μm filter to obtain a photosensitive colored composition.

モノマー ：トリメチロールプロパントリアクリレート
（新中村化学社製「ＮＫエステルＡＴＭＰＴ」）
光重合開始剤：2-メチル-1-[4-（メチルチオ）フェニル]-2-モルフォリノプロパン-1-オン
（チバ・スペシャルティ・ケミカルズ社製「イルガキュア９０７」）
増感剤 ：４，４’−ビス（ジエチルアミノ）ベンゾフェノン
（保土ヶ谷化学社製「ＥＡＢ−Ｆ」）
有機溶剤 ：シクロヘキサノン
［カラーフィルタの作製］
得られた感光性着色組成物を用いてカラーフィルタを作製した。
ガラス基板３、表２の赤色感光性着色組成物をスピンコートにより膜厚２μｍとなるように塗布した。乾燥の後、露光機にてストライプ状のパターン露光をし、アルカリ現像液にて９０秒間現像して、ストライプ状の赤色画素の着色画素を得た。なお、アルカリ現像液は以下の組成からなる。

Monomer: Trimethylolpropane triacrylate (“NK ester ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (“Irgacure 907” manufactured by Ciba Specialty Chemicals)
Sensitizer: 4,4′-bis (diethylamino) benzophenone (“EAB-F” manufactured by Hodogaya Chemical Co., Ltd.)
Organic solvent: cyclohexanone [Preparation of color filter]
A color filter was produced using the photosensitive coloring composition obtained.
The red photosensitive coloring composition of the glass substrate 3 and Table 2 was apply | coated so that it might become a film thickness of 2 micrometers by spin coating. After drying, striped pattern exposure was performed with an exposure machine, and development was performed with an alkaline developer for 90 seconds to obtain colored pixels of striped red pixels. The alkaline developer has the following composition.

Sodium carbonate 1.5% by weight
Sodium bicarbonate 0.5% by weight
Anionic surfactant 8.0% by weight
("Peralex NBL" manufactured by Kao Corporation)
90% by weight of water
Next, the green photosensitive coloring composition of Table 2 was similarly applied by spin coating so that the film thickness was 2 μm. After drying, a striped colored pixel was exposed and developed at a place shifted from the above-mentioned red pixel by an exposure machine, thereby obtaining a green pixel adjacent to the above-mentioned red pixel.

  Further, in the same manner as in red and green, the blue photosensitive colored composition shown in Table 2 was also obtained with a blue pixel adjacent to the red and green pixels with a film thickness of 2 μm. Thus, a color filter having striped colored pixels of three colors of red, green, and blue on the transparent substrate was obtained.

  In the transflective liquid crystal display device, a substrate in which a reflector, a TFT element, a pixel electrode, etc. are separately formed on a non-alkali glass is prepared as a counter substrate, and a color filter in which three colored pixels are formed and a counter substrate. The alignment film was printed and rubbed for alignment. However, the reflection plate on the counter substrate is formed only in the reflection region in the pixel. A sealing agent kneaded with microrods was printed on one of these two substrates, and 4 μm thick bead spacers were dispersed, and then the two substrates were bonded together. Next, TN liquid crystal (refractive index anisotropy Δn to 0.1) compatible with 4V driving was injected to close the liquid crystal injection port with a sealing agent. A liquid crystal cell into which liquid crystal was injected was sandwiched between orthogonal polarizing films to prepare a liquid crystal cell for evaluation. On the back surface of the liquid crystal cell, backlights made on two sides of a light guide plate made of polymethyl methacrylate (refractive index 1.49, critical reflection angle about 42 °) were arranged. A transflective liquid crystal display device was completed by mounting an IC driver or the like on the liquid crystal cell.

  RR-1 is used as the red photosensitive coloring composition, RG-1 is used as the green photosensitive coloring composition, RB-1 and RB-2 are used as the blue photosensitive coloring composition, and three colored pixels are formed by the above method. The results obtained by combining the formed color filters CF-1 and CF-2 with the backlight having the three-color LED were defined as Examples 1 and 2. Similarly, Comparative Examples 1 and 2 were obtained by combining color filters CF-1 and CF-2 with a backlight having a two-wavelength white LED. Using RR-1 as the red photosensitive coloring composition, RG-2 as the green photosensitive coloring composition, and RB-1 as the blue photosensitive coloring composition, three colored pixels were formed by the above method. The result of combining the color filter CF-3 and the backlight having the three-color LED was set as Comparative Example 3.

  RR-2 as a red photosensitive coloring composition, RG-3 as a green photosensitive coloring composition, RB-3 as a blue photosensitive coloring composition, and a color in which three colored pixels are formed by the above method The result of combining the filter CF-4 and the backlight having the three-color LED was set as Comparative Example 4.

  RR-2 as a red photosensitive coloring composition, RG-3 as a green photosensitive coloring composition, RB-3 as a blue photosensitive coloring composition, and a color in which three colored pixels are formed by the above method The result obtained by combining the filter CF-4 and the backlight having the two-wavelength white LED was set as Comparative Example 5.

As the chromaticity of transmissive display, the chromaticity of red, green, and blue pixels and the chromaticity of white display (white point) of the produced color filter were measured using the produced backlight.
As chromaticity similarly reflective display was measured each chromaticity using standard light D _65.
The results are shown in Table 3.

The spectral transmittances of the red, green, and blue pixels of the produced color filters CF-1 to CF-4 were measured using a microspectrophotometer ("OSP-SP100" manufactured by Olympus Optical Co., Ltd.). The measured spectral transmittances are the transmittances T _R , T _G , T _{B at} the red, green, and blue peak wavelengths of the three-color LED, and the transmittances (T _G600 ), (T _G650 ) of the green pixels at 600 nm and 650 nm. Are shown in Table 3.

  Table 3 shows the color reproducibility in transmissive display and the visibility (brightness of display) in reflective display of the liquid crystal display device manufactured by the above method.

[色再現性]
○ ・・・ 透過表示におけるＮＴＳＣ比が７０％以上
× ・・・ 透過表示におけるＮＴＳＣ比が７０％未満
[視認性]
○ ・・・ 反射表示が明るく、視認性が良好
× ・・・ 反射表示が暗く、視認性不良
実施例１および実施例２の液晶表示装置にフルフィールドカラーバーを表示し、視認性を評価したところ、透過表示はＮＴＳＣ比が７０％以上と高く、色再現性が良好で色が鮮やかな表示であった。また、標準の光Ｄ₆₅により測色した白色点のＹ値は３５で、反射表示は明るく視認性が良好であった。

[Color reproducibility]
○ ... NTSC ratio in transmissive display is 70% or more × ... NTSC ratio in transmissive display is less than 70%
[Visibility]
○ ... Reflection display is bright and visibility is good × ... Reflection display is dark and visibility is poor Displaying full-field color bars on the liquid crystal display devices of Example 1 and Example 2 and evaluating the visibility However, the transmissive display had a high NTSC ratio of 70% or more, had good color reproducibility, and a vivid color display. Further, the Y value of the white point measured by the standard light D ₆₅ was 35, and the reflective display was bright and the visibility was good.

In Comparative Example 1 and Comparative Example 2, the Y value of the white point measured by the standard light D ₆₅ was 35 and the reflective display was good, but the transmissive display had an NTSC ratio of 70% or less and the color reproducibility was poor. It lacks freshness. In Comparative Examples 3 and 5, the transmissive display was good, but the transmittances (T _G600 ) and (T _G650 ) were small, and the Y value of the white point measured by the standard light D ₆₅ was low. The reflection display was dark and the color of the full field color bar could not be identified. In Comparative Example 4, since the transmittance was low and the brightness of the transmissive display was poor, and the Y value of the white point was low, the reflective display was dark and the color of the full field color bar could not be identified.

The emission spectrum of a two-wavelength white LED. The emission spectrum of 3 color LED in this invention.

Claims (4)

A color filter used in a transflective liquid crystal display device using a white LED mixed with a combination of a red LED, a green LED, and a blue LED as a backlight. The color filter is composed of a red pixel, a green pixel, and a blue pixel. The spectral transmittance of the green pixel is such that the transmittance at a wavelength of 600 nm (T _G600 ) is [55% ≦ T _G600 ≦ 85%], and the transmittance at a wavelength of 650 nm (T _G650 ) is [15% ≦ T _G650 ≦ 35%].   In the red pixel corresponding to the red LED, the green pixel corresponding to the green LED, and the blue pixel corresponding to the blue LED, the transmittance of each color pixel at the peak wavelength of the emission spectrum of each color LED is 80% or more, respectively. The color filter according to claim 1, wherein the color filter is provided. In the color filter according to claim 1 or claim 2, wherein the tristimulus value Y of the white point of the standard light D ₆₅ (W) is not less than 35, the color reproduction range in combination with the backlight CIE1931XYZ color system A color filter having an NTSC ratio of 70% or more on the xy chromaticity diagram.   A transflective liquid crystal display device using the color filter according to claim 1.

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