JP5228991B2 - Color filter and liquid crystal display device including the same - Google Patents

Description

  The present invention relates to a color filter and a liquid crystal display device including the color filter, and more particularly to a color filter having a slit in a pixel electrode on a colored layer and a liquid crystal display device including the color filter.

  Color liquid crystal display devices are rapidly spreading mainly in computer terminal display devices and television image display devices. The color filter is an indispensable important component for color display of a liquid crystal display device. In recent years, this liquid crystal display device has a high demand for higher image quality, and various new types of liquid crystal display devices having a high viewing angle and high-speed response have appeared. FIG. 1 shows an alignment division vertical alignment type liquid crystal display device (MVA (Multi-domain Vertical Alignment) -LCD) which is controlled so that the alignment directions of liquid crystal molecules in one pixel are a plurality of directions. It is explanatory drawing which showed typically the cross section of an example.

  As shown in FIG. 1, in this MVA liquid crystal display device, a colored layer (12) and a pixel electrode (13) having a slit are provided on a glass substrate (11) through liquid crystal molecules (30). In this structure, a color filter (10) and a counter substrate (20) provided with TFT elements (not shown), pixel electrodes (22), and protrusions (23a, 23b) are arranged on a glass substrate (21). . The protrusions (23a, 23b) and the slits (14) are provided at alternate positions within one pixel. These protrusions and slits have a function of controlling the alignment of liquid crystal molecules. In the state of voltage application, the liquid crystal molecules between the protrusion (23a) and the slit (14) are inclined to the left in FIG. 1, and the liquid crystal molecules between the slit (14) and the protrusion (23b) are inclined to the right in FIG. Inclined to. This liquid crystal display device controls the alignment of liquid crystal molecules by providing protrusions and slits instead of rubbing treatment.

  The edge of the slit (14) of the pixel electrode has an effect of controlling the alignment in the same manner as the alignment control protrusions (23a, 23b) because the distortion of the electric field generated in the vicinity of the edge affects the alignment. When slits are used instead of the projections, there is no projection for tilting the liquid crystal molecules, so that light leakage from this portion is reduced and the contrast is improved. The pixel electrode is a transparent conductive film made of ITO (indium tin oxide), zinc oxide, tin oxide or the like, and the slit is formed by photoetching. However, the color filter having the above structure has a problem that the liquid crystal molecules are directly affected by the electrical characteristics of the material of the colored layer because there is a slit on the colored layer constituting the pixel.

  In fact, when a conventional colored layer material is used, in an MVA type liquid crystal display device, an image burn-in phenomenon (an image on a display screen for a long time) due to poor liquid crystal alignment due to the electrical characteristics of the colored layer material and a switching threshold shift. Various display defects such as fixed phenomenon) occurred. Therefore, when a conventional color filter made of a colored layer material is used for an MVA liquid crystal display device, for example, Patent Document 1 discloses a technique disclosed as a color filter adapted to a lateral electric field (IPS: In-Plane Switching) method. Similarly, it is common to provide a protective layer (overcoat layer) of a transparent resin on the colored layer so that the liquid crystal sandwich surface and the colored layer do not directly touch each other.

However, the price of liquid crystal display devices in recent years has been remarkably reduced, and the color filter that is a member of the liquid crystal display device has been urged to reduce the price. As described above, by providing an overcoat layer made of a transparent resin, even a conventional colored layer material can be used for an MVA liquid crystal display device. However, in order to ensure sufficient performance, the overcoat layer may be used in some cases. Needs to be provided with a thickness of 2 μm or more, which causes a problem that it is difficult to apply uniformly, which is one factor that hinders cost reduction.

  Patent Document 2 discloses a technique in which a resin having a structure including an aromatic ring is used as a photosensitive material as a color filter for an MVA liquid crystal display device, which is effective in reducing dielectric loss tangent and does not cause display burn-in. Is disclosed. As described above, the coloring layer material and the overcoat layer material have been improved so as to be compatible with the MVA type liquid crystal display device. However, the MVA type liquid crystal display device is not provided with an overcoat layer. A color filter that can be used is desired.

JP 2004-117537 A JP 2004-347919 A

  The present invention has been made in order to solve the above-described problems. In a color filter used in an MVA liquid crystal display device, a color layer constituting the color filter is formed even if a slit is provided in a pixel electrode. A color filter whose electrical properties do not adversely affect liquid crystal alignment failure and switching threshold shift, and thus can ensure sufficient performance without providing a protective layer (overcoat layer) made of a transparent resin. It is an object to provide a liquid crystal display device including the same.

The invention according to claim 1 of the present invention is the color filter comprising a pixel electrode having at least a red pixel, a green pixel, and a blue pixel on a transparent substrate, and having a slit provided on each pixel. The dielectric loss tangent (tan δ) of the colored layer constituting the pixel is 0.025 or less in the frequency range of 10 Hz to 100 Hz, the thickness of the colored layer of the green pixel is 1.0 μm to 3.0 μm, and the film of the green pixel Mass obtained by reacting styrene and an unsaturated carboxylic acid-containing monomer as a transparent resin at least in a green coloring composition of a green pixel and having a chromaticity y of 0.57 or more at a thickness of 1.5 μm an average molecular weight of 30,000 or less, and polymer composition is less than the solid content acid value 10~150mgKOH / g, styrene content of more than 75 mol% 95 mol%, copper halide lid A color filter which comprises a cyanine pigment. The copper halide phthalocyanine pigment described above is representative as a green color filter pigment and has excellent spectral transmission spectral characteristics and light resistance.

The invention according to claim 2 of the present invention includes a colored layer formed simultaneously with the formation of the green pixel, the red pixel, and the blue pixel when the slit is formed in the pixel electrode on each pixel by photoetching. pixel electrode portion on color laminated photo spacer, a color filter according to claim 1, characterized in that it is simultaneously removed by the photoetching.

The invention according to claim 3 of the present invention, the dielectric constant of the colored layer of each pixel, one of the claims 1-2, characterized in that more than 5.0 in the frequency range of 10Hz~100Hz Or a color filter described in item 1.

In the invention according to claim 4 of the present invention, a pixel electrode provided with a slit is provided on the colored layer of each pixel without a protective layer, and the colored layer is exposed to the liquid crystal sandwiching surface from the slit. The color filter according to any one of claims 1 to 3 , wherein the color filter is used.

According to a fifth aspect of the present invention, there is provided a liquid crystal display device comprising the color filter according to any one of the first to fourth aspects.

  Since the color filter of the present invention is a color filter in which a color layer having a dielectric loss tangent of 0.025 or less in a frequency range of 10 Hz to 100 Hz and having a slit in a pixel electrode on the color layer, an MVA liquid crystal display When used in the device, the electrical properties of the colored layer of the color filter do not adversely affect the switching performance of the liquid crystal, and even without providing a protective layer (overcoat layer) with a transparent resin, The color filter has no switching threshold shift, that is, does not adversely affect the display performance and can ensure sufficient reliability.

It is a schematic diagram which shows an example of the liquid crystal display device of a MVA system in a cross section. It is a figure which shows the frequency characteristic of the dielectric loss tangent of the red colored layer of the conventional color filter. It is a figure which shows the frequency characteristic of the dielectric loss tangent of the green colored layer of the conventional color filter. It is a figure which shows the frequency characteristic of the dielectric loss tangent of the blue colored layer of the conventional color filter. It is a figure which shows the relationship between content of the transparent resin contained in a green coloring composition, and a dielectric loss tangent. It is sectional drawing of an example of the color filter concerning Claim 3. It is sectional drawing of an example of the conventional color filter provided with the color lamination | stacking photospacer.

  Below, the color filter of this invention is demonstrated in detail based on the one Embodiment.

  As a result of various studies on the relationship between the electrical properties of the color filter and the display failure in the MVA liquid crystal display device, the present inventors mainly found that the liquid crystal alignment failure and the switching threshold shift of the MVA liquid crystal display device are mainly. We have found that this is caused by the dielectric properties of the colored layer. Specifically, it can be explained by the value of dielectric loss tangent. It is based on the following mechanism. The dielectric loss tangent (tan δ) is the ratio between the amount of charge accumulated in the dielectric and the amount of charge consumed. When the dielectric loss tangent is relatively small, the charge accumulated in the dielectric is retained, whereas when the dielectric loss is relatively large, the charge is consumed and not retained.

As described above, FIG. 1 schematically shows a cross section of an example of the MVA liquid crystal display device. In the MVA type liquid crystal display device, the colored layer (12) constituting the color filter (10) is disposed so as to face inward and is inherent in the liquid crystal driving electric field. If the value of the dielectric loss tangent of the colored layer differs greatly from the dielectric loss tangent of a member (liquid crystal, alignment film, etc.) in another cell, a phenomenon occurs in which the charge retention state of the liquid crystal molecules becomes non-uniform.

  Due to the non-uniform state of charge retention, a liquid crystal alignment defect occurs, or a display defect such as image sticking occurs due to a switching threshold shift. Therefore, the dielectric loss tangent of the colored layer constituting the color filter is an important characteristic that determines the display characteristics of the MVA liquid crystal display device. The dielectric loss tangent is a value depending on the measurement frequency, but since one frame for driving the liquid crystal is about 60 Hz, attention is paid to the dielectric loss tangent at a period (second), that is, a frequency around 30 Hz, and a frequency of about 10 to 100 Hz. Is appropriate.

  Here, the measurement results of the dielectric loss tangent of several kinds of colored layers used in the conventional color filter are shown in FIG. 2, FIG. 3, and FIG. The dielectric loss tangent of the colored layer of each color constituting the conventional color filter is in the range of 10 Hz to 100 Hz, and shows a value of about 0.006 to 0.25 depending on the type of the colored layer. As shown in FIG. 3, in particular, the green colored layer has a large dielectric loss tangent, and in fact, at least in the green colored layer, if the overcoat layer is not provided at the boundary with the liquid crystal sandwiching surface, the liquid crystal alignment failure and switching It was easy for the threshold deviation of the above to occur remarkably.

  In the color filter used in a liquid crystal display device, in particular, an MVA liquid crystal display device having a slit in a pixel electrode, even if an overcoat layer is not provided at the boundary between the colored layer and the liquid crystal sandwiching surface, In order to provide a color filter that can improve the display quality by eliminating liquid crystal alignment defects and switching threshold shifts, various studies have been made on improving this characteristic dielectric property.

  In general, a liquid crystal, an alignment film, or the like is formed using a material having a large ability to hold charges, that is, a dielectric tangent is relatively small, and its value is generally about 0.005 to 0.02. Therefore, it is considered that the value of the dielectric loss tangent of the colored layer provided in the color filter used in the MVA liquid crystal display device is preferably the same value as that of the liquid crystal and the alignment film.

  That is, in the multicolored color filter for liquid crystal display devices, the dielectric loss tangent of the colored layer constituting the pixel provided in the color filter is about 0.025 or less, more preferably 0.015 or less in the range of 10 Hz to 100 Hz. Thus, it has been found that deterioration in display quality such as pixel orientation failure and threshold deviation can be effectively prevented without providing an overcoat layer on the pixel. The lower the dielectric loss tangent of the colored layer is, the more preferable, but the lower limit is about 0.005 to 0.006 at present due to the characteristics of the material of the colored layer.

  As a result of various studies, it has been found that in the color filter of the present invention, it is preferable that the relative dielectric constant of the colored layer is 5.0 or less in the frequency range of 10 Hz to 100 Hz. The relative dielectric constant is an index of the amount of charge accumulated in the dielectric body. If the value is significantly large in the colored layer, the balance of the amount of charge accumulated between the members in the cell (liquid crystal, alignment film, etc.) is greatly disrupted. Thus, display failure such as burn-in occurs due to a deviation of the switching threshold. Therefore, the relative dielectric constant of the colored layer of the color filter needs to be 5.0 or less, more preferably 4.5 or less at a frequency of 10 Hz to 100 Hz. A lower relative dielectric constant is preferable, but about 3.0 is the lower limit at the present time due to material characteristics.

  Conventionally, as a method for realizing these characteristics, for example, in Patent Document 1 or 2, the concentration of a pigment that is a component having a high dielectric loss tangent is set to a certain level or less, the purity of the pigment is improved, and the dielectric loss tangent of the pigment itself is set. It has been reported to be smaller.

However, since these methods limit the degree of freedom in selecting a pigment, it may be difficult in terms of labor, time, and cost to meet various color characteristic requirements. Accordingly, as a result of intensive studies, the present inventors can easily suppress the dielectric loss tangent of the colored layer to 0.025 or less by forming the colored layer using a colored resin composition containing a certain resin. I found out that This broadens the range of pigment selections, making it easy to provide color filters with color characteristics that meet various required specifications, thereby speeding up development and reducing development and material costs. Is also connected.

  FIG. 6 is a cross-sectional view of an example of a color filter according to claim 3 of the present invention. The color filter shown in FIG. 6 is a color filter used for an MVA type liquid crystal display device, but is provided with a color laminated photo spacer. This color laminated photo spacer (3C-PS) is composed of a pattern of at least one color of a green dot pattern (16G), a red dot pattern (16R), and a blue dot pattern (16B). Each of these color dot patterns is formed at the same time as the formation of the colored pixels of the three colors, using the same material as that of the colored layer used for forming the green pixel, the red pixel, and the blue pixel. Lamination is performed in one to three colors, and the number of laminations may be appropriately selected according to the specifications of the photo spacer.

  After the pixel electrode (13) is provided on the entire surface of the transparent substrate (11) on which the color laminated photospacer is formed, a slit (14) is formed by photoetching. The color laminated photospacer (3C-PS) The portion indicated by the upper dotted line is the portion of the pixel electrode (13) removed by photoetching simultaneously with the formation of the slit (14). In this manner, the pixel electrode (13) portion on the three-color laminated photospacer (3C-PS) is removed, and a dot pattern, for example, a blue dot pattern (16B) is exposed. The dot pattern made of the coloring layer material has an insulating property. Therefore, the insulating dot pattern (17) of the conventional color filter shown in FIG. 7 becomes unnecessary.

  FIG. 7 is a cross-sectional view of an example of a conventional color filter provided with a color laminated photospacer (3C-PS). Since the pixel electrode (13) is collectively provided on the color filter, as shown in FIG. 7, the pixel electrode (13) is provided on the color laminated photospacer (3C-PS). An insulating dot pattern (17) is provided via the pixel electrode (13). This insulating dot pattern (17) is for preventing an electrical short circuit with the counter substrate and is insulative. According to the color filter according to claim 3 of the present invention, such an insulating dot pattern (17) is not required, and an inexpensive color filter can be obtained.

  Hereinafter, a method for obtaining the color filter of the present invention will be described. The color filter of the present invention includes pixels of a plurality of colors on at least a transparent substrate, and the pixels of the plurality of colors are composed of at least a colored layer. Multiple colors include combinations of red, green, blue (RGB) and yellow, magenta, cyan (YMC). The color filter of the present invention is different from a color filter having a green colored layer (ie, RGB system). It can be applied particularly preferably.

  The color filter of the present invention is used by being incorporated in a liquid crystal display device with the pixel formation surface facing the liquid crystal sandwiching surface. An alignment film is formed on the pixels as necessary. Since the color filter of the present invention does not affect the electric characteristics of the colored layer in the liquid crystal driving electric field, it is not necessary to provide an overcoat layer covering the colored layer, so that the yield is good and the cost is reduced. In addition, since the distance between the liquid crystal and the pixel becomes closer, the viewing angle is improved and a high-definition liquid crystal display device can be provided.

  As described above, in the color filter of the present invention, it is not necessary to provide an overcoat layer in order to supplement the electrical characteristics of the colored layer, but a resin layer can be provided for the purpose of flattening the color filter. In this case, the thickness as in the conventional overcoat layer is not necessary.

  The transparent substrate used in the color filter of the present invention 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 chrome or a pattern made of a light shielding resin previously attached to the transparent substrate by a known method.

  The colored layer on the transparent substrate may be produced by any known method such as an inkjet method, a printing method, a photolithography method, or an etching method. However, considering high definition, controllability and reproducibility of spectral characteristics, etc., a colored resin composition in which a pigment is dispersed in a transparent resin together with a photoinitiator and a polymerizable monomer in a suitable solvent is formed on a transparent substrate. A photolithography method is preferred in which a color filter is produced by repeatedly forming a coating film on the coating film and pattern-exposing and developing the coating film to form a colored layer of one color for each color.

  When the colored layer constituting the pixel included in the color filter of the present invention is prepared by photolithography by preparing a colored resin composition, for example, the following method is used. A pigment serving as a colorant is dispersed in a suitable solvent together with a photoinitiator and a polymerizable monomer in a transparent resin. There are various methods such as mill base, three rolls, jet mill and the like, and there are no particular limitations.

  Specific examples of organic pigments that can be used in the colored resin composition of the present invention are indicated by color index numbers.

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

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 20, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 86, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 125, 126, 127, 128, 129, 137, 138, 139, 144, 146, 147, 148, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 1 73, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 199, 213, 214 and the like.

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

Examples of the green colored resin composition for forming the green filter segment include C.I. I. Green pigments such as Pigment Green 7, 10, 36, 37, and 58 can be used. The green colored resin composition can be used in combination with the same yellow pigment as the red colored resin composition.

  Examples of the blue colored resin composition for forming the blue filter segment include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 80, etc., preferably C.I. I. Pigment Blue 15: 6 can be used.

  The blue colored resin composition includes C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like, preferably C.I. I. Pigment Violet 23 can be used in combination.

  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.

  As a transparent resin that can be used in the colored resin composition according to the present invention, it has been found that a photosensitive composition including a polymerization composition obtained by reacting styrene with an unsaturated carboxylic acid-containing monomer exhibits excellent performance. It was. That is, such a photosensitive composition is imparted with desired developability, is excellent in long-term storage stability and development speed, and further, the coating film after being cured by light irradiation and / or baking is heat resistant. It is excellent in adhesion to the substrate, hardness, solvent resistance, and alkali resistance, and can solve the problems of the conventional techniques described above.

  The above-described polymerization composition according to the present invention is obtained by reacting styrene and an unsaturated carboxylic acid-containing monomer, and has a mass average molecular weight of 30000 or less and a solid content acid value of 10 to 150 mgKOH / g. Such a polymerization composition has a mass average molecular weight of 30000 by radical copolymerizing and reacting an ethylenically unsaturated group of styrene and an ethylenically unsaturated group of an unsaturated carboxylic acid-containing monomer in an organic solvent. Hereinafter, a polymerization composition having a solid content acid value of 10 to 150 mgKOH / g can be obtained.

  Thus, when a photosensitive resin composition is prepared by blending a polymerization composition having a mass average molecular weight of 30000 or less or a solid content acid value of 10 to 150 mgKOH / g, a conventional mass average molecular weight of 30000 or more, or Problems when a photosensitive resin composition containing a styrene-containing polymerization composition with a solid content acid value other than 10 to 150 mgKOH / g is used, that is, the alkali developability of the photosensitive resin composition is deteriorated, and the development speed is moderate. The effect of the styrene-containing polymerization composition can be sufficiently exhibited without causing adverse effects such that the development time cannot be adjusted and the development time becomes long, or the development speed is too high and the coating film is easily peeled off from the substrate. It becomes possible.

Moreover, the polymerization composition of the present invention further has a styrene content of 75 mol% or more and less than 95 mol%. When a photosensitive resin composition is prepared by blending a polymer composition having a styrene content of 75 mol% or more and less than 95 mol% as described above, it becomes possible to express the property of reducing tan δ possessed by a styrene resin. It is possible to cancel and reduce the problems that have occurred in the type-sensitive color filter, that is, the high dielectric loss tangent that has been caused by the influence of pigments, dispersants, and other binder resins. This makes it possible to provide a liquid crystal display device that can satisfy the originally desired dielectric loss tangent threshold value and has good display characteristics. When the styrene content is less than 75 mol%, the dielectric loss tangent of the colored resin composition cannot be sufficiently canceled, and the effect of reducing tan δ cannot be exhibited. When the styrene content exceeds 95 mol%, the compatibility with other components in the photosensitive resin composition is deteriorated, the storage stability of the photosensitive resin composition is deteriorated, and the styrene-containing resin is deteriorated. The content of alkali-soluble groups in the composition is reduced, resulting in a problem that developability deteriorates.

  Examples of the unsaturated carboxylic acid-containing monomer according to one embodiment of the present invention described above include acrylic acid, methacrylic acid, maleic acid, monoalkylmaleic acid, fumaric acid, monoalkylfumaric acid, itaconic acid, and monoalkylitaconic acid. And crotonic acid. Of these, acrylic acid and methacrylic acid are preferably used.

  Moreover, the following can be illustrated as acrylic resin used for this invention. Examples of acrylic resin materials include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and t-butyl (meth) acrylate penzyl (meth) ), Alkyl (meth) acrylates such as lauryl (meth) acrylate, hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, ethoxyethyl (meth) acrylate, glycidyl (meth) acrylate Ether group-containing (meth) acrylates such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and other alicyclic (meth) acrylates are used as monomers Polymer, and the like.

  In addition, these monomers can be used individually or in combination of 2 or more types. Furthermore, compounds such as styrene, cyclohexylmaleimide, and phenylmaleimide that can be copolymerized with these acrylates can be copolymerized.

  In addition, for example, copolymerizing a carboxylic acid having an ethylenically unsaturated group such as (meth) acrylic acid, and reacting the resulting resin with an epoxy group such as glycidyl methacrylate and a compound containing an unsaturated double bond, By adding a carboxylic acid-containing compound such as (meth) acrylic acid to a resin obtained by homopolymerization of an epoxy such as glycidyl methacrylate, or a copolymer of (meth) acrylate or other (meth) acrylate with them. The resin which has it can be obtained.

  Furthermore, a resin having photosensitivity can be obtained by reacting, for example, a hydroxyl group-containing resin having hydroxyethyl methacrylate or the like as a monomer with an isocyanate group such as methacryloyloxyethyl isocyanate and a compound having an ethylenically unsaturated group.

  In addition, as described above, a resin having a carboxyl group, which is prepared by copolymerization of hydroxyethyl methacrylate and the like, and a polybasic acid anhydride is further reacted with a resin having a plurality of hydroxyl groups to introduce a carboxyl group into the resin. However, the manufacturing method is not limited to the method described above.

  Examples of acid anhydrides used in the above reaction include, for example, malonic acid anhydride, succinic acid anhydride, maleic acid anhydride, itaconic acid anhydride, phthalic acid anhydride, tetrahydrophthalic acid anhydride, hexahydrophthalic acid anhydride , Methyltetrahydrophthalic anhydride, trimellitic anhydride and the like.

  It is preferable that the solid content acid value of the acrylic resin described above is 20 to 180 mgKOH / g. When the acid value is less than 20 mgKOH / g, the development speed of the photosensitive resin composition is too slow, and the time required for development increases, resulting in poor productivity. On the other hand, when the acid value is larger than 180 mgKOH / g, the development speed is too high, and pattern peeling or pattern defect after development occurs.

Furthermore, when the acrylic resin has photosensitivity, the double bond equivalent of the acrylic resin is preferably 100 to 2000, and more preferably 100 to 1000. When the double bond equivalent exceeds 2000, sufficient photocurability cannot be obtained.

  A transparent resin can also be added to the colored resin composition according to the present invention as necessary. The transparent resin has 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, and a dielectric loss tangent of 0.008 or less in the frequency range of 10 Hz to 100 Hz. It becomes resin. 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 such resins include polyester resins, polystyrene, styrene-maleic acid copolymers, polyimide resins, epoxy resins, benzoguanamine resins, melamine resins, urea resins, novolac resins, polyvinylphenol resins, and modified ones thereof. Etc. Among these, a photopolymerizable unsaturated group-containing resin obtained by further reacting a reaction product of an epoxy resin and an unsaturated group-containing carboxylic acid or its anhydride with a polybasic carboxylic acid or its anhydride, or a novolak A resin, a resin having a phenolic hydroxyl group such as a polyvinylphenol resin, or a modified resin thereof is particularly preferable in terms of developability, patterning characteristics, cost, and the like.

  Examples of polymerizable monomers and oligomers that can be used in transparent resins include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 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 ester Terdi (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, Various acrylic esters and methacrylic esters such as epoxy (meth) acrylate and 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. These can be used alone or in admixture of two or more.

When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the colored resin composition. Examples of the photopolymerization initiator include 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 ' Benzophenone-based compounds such as methyldiphenyl sulfide, 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-4,6bis (trichloro Methyl) -s-triazine, 2,4-bis (trichloro) Til) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine 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-tri Phosphine compounds such as chill benzoyl diphenyl phosphine oxide,
Quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethyl anthraquinone, borate compounds, carbazole compounds, imidazole compounds, titanocene compounds, and the like 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 colored resin 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 colored resin composition can contain a polyfunctional thiol that functions as a chain transfer agent. The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris (2-hydroxyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercap -s- triazine, 2- (N, N- dibutylamino) -4,6-dimercapto -s- triazine. These polyfunctional thiols can be used alone or in combination. The amount of the polyfunctional thiol used is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass based on the total solid content of the colored resin composition. If it is less than 0.1% by mass, the effect of adding a polyfunctional thiol is insufficient, and if it exceeds 30% by mass, the sensitivity is too high and the resolution is lowered.

The colored resin 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.

  On the transparent substrate, the above-mentioned colored resin composition is applied and prebaked. As a means for applying, spin coating, dip coating, die coating, etc. are usually used, but it is not limited to these as long as it can be applied on the substrate with a uniform film thickness. Prebaking is preferably performed at 90 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 colored resin composition is applied and the colored layer is formed is exposed through a pattern mask. A normal high-pressure mercury lamp or the like may be used as the light source.

  Subsequently, development is performed. 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, dried and post-baked to obtain a pixel of any one color. In addition, it is preferable to perform a post-baking at 180 to 260 degreeC for about 15 to 60 minutes.

  By repeating the above-described series of steps by changing the colored resin composition and the pattern as many times as necessary, it is possible to obtain a colored pattern in which a necessary number of colors are combined, that is, a pixel of a plurality of colors.

  Hereinafter, specific examples of the present invention will be described. It should be noted that the present invention is not limited to this without departing from the spirit of the present invention.

[Preparation of resin solution]
A polymerization composition comprising styrene and a non-aromatic polyvalent carboxylic acid-containing monomer used in Examples and Comparative Examples was prepared as follows. The molecular weight of the resin is a polystyrene-reduced mass average molecular weight measured by GPC (gel permeation chromatography).

<Polymerization composition>
24 g of styrene-acrylic resin emulsion (AP1761, manufactured by Showa Polymer Co., Ltd., resin solid content 50%) and 96 g of propylene glycol monomethyl ether acetate were added and heated at 30 ° C. for 1 hour. The weight average molecular weight of the obtained styrene-acrylic acid copolymer was 4400.

<Acrylic resin>
In a five-necked reaction vessel having an internal volume of 0.02 m ² , 800 g of propylene glycol monomethyl ether acetate, 10 g of methacrylic acid, 40 g of methyl methacrylate, 80 g of butyl methacrylate, 40 g of hydroxyethyl methacrylate and 2 g of azobisisobutyronitrile are added, While blowing nitrogen gas, heating was performed at 80 ° C. for 6 hours to obtain an acrylic resin. The obtained acrylic resin 1 had a mass average molecular weight of 40,000.

[Preparation of colored resin composition]
Red, blue and green colored resin compositions were prepared in the following manner. “Parts” are all parts by mass.

<Red pigment dispersion>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a red pigment dispersion. -Red pigment: C.I. I. Pigment Red 254
("Ilgar Forred B-CF" manufactured by Ciba Specialty Chemicals)
18 parts red pigment: C.I. I. Pigment Red 177
("Chromophthal Red A2B" manufactured by Ciba Specialty Chemicals)
2 parts Dispersant (Ajinomoto Fine Techno "Ajisper PB821") 2 parts Acrylic resin 1 108 parts

<Red colored resin composition>
Thereafter, a mixture having the following composition was stirred and mixed so as to be uniform, and then filtered through a 5 μm filter to obtain a red colored resin composition.
・ 130 parts of the above red pigment dispersion ・ 13 parts of trimethylolpropane triacrylate (“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.) ・ 3 parts of photoinitiator (“Irgacure 907” manufactured by Ciba Geigy Co.) ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 1 part ・ cyclohexanone 253 parts

<Blue pigment dispersion>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a blue pigment dispersion. Blue pigment: C.I. I. Pigment Blue 15
(Toyo Ink Mfg. Co., Ltd. “Lionol Blue ES”) 50 parts Purple pigment: C.I. I. Pigment Violet 23
(BASF "Paliogen Violet 5890") 2 parts Dispersant (Zeneca "Sols Birds 20000") 6 parts Acrylic resin 1 200 parts

<Blue colored resin composition>
Thereafter, a mixture having the following composition was stirred and mixed so as to be uniform, and then filtered through a 5 μm filter to obtain a blue colored resin composition.
-268 parts of the above blue pigment dispersion-19 parts of trimethylolpropane triacrylate ("NK ESTER ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.) 4 parts of photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts, cyclohexanone 214 parts

<Green pigment dispersion 1>
A mixture of the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using a glass bead having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare Green Pigment Dispersion 1.
Green pigment: C.I. I. Pigment Green 36
(Toyo Ink Manufacturing Co., Ltd. “Lionol Green 6YK”) 19 parts Yellow pigment: C.I. I. Pigment Yellow 150
(Bayer's "Funcheon First Yellow Y-5688") 5.2 parts Dispersant (Bicchemy's "Disperbyk-163") 2 parts Acrylic resin 1 60 parts

<Green colored resin composition 1>
Thereafter, a mixture having the following composition was stirred and mixed to be uniform, and then filtered through a 5 μm filter to obtain a green colored resin composition 1.
-86 parts of green pigment dispersion-56 parts of polymerization composition-10 parts of trimethylolpropane triacre ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) ) 4.5 parts-Sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts-166 parts cyclohexanone

<Green colored resin composition 2>
-86 parts of green pigment dispersion-70 parts of polymerization composition-10 parts of trimethylolpropane triacrylate ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4.5 parts ・ Sensitizer (Hodogaya Chemical Co., Ltd. “EAB-F”) 2 parts ・ Cyclohexanone 166 parts

<Green colored resin composition 3>
-86 parts of green pigment dispersion-50 parts of polymerization composition-10 parts of trimethylolpropane triacrylate ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4 parts ・ Sensitizer (Hoabaya Chemical Co., Ltd. “EAB-F”) 2 parts ・ Cyclohexanone 166 parts

<Green colored resin composition 4>
-86 parts of green pigment dispersion-70 parts of acrylic resin-10 parts of trimethylolpropane triacrylate ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4 .5 parts-Sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts-Cyclohexanone 166 parts

<Green colored resin composition 5>
-86 parts of green pigment dispersion-135 parts of acrylic resin-10 parts of trimethylolpropane triacrylate ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4 .5 parts-Sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 2 parts-Cyclohexanone 166 parts

<Green colored resin composition 6>
-86 parts of green pigment dispersion-48 parts of polymerization composition-10 parts of trimethylolpropane triacrylate ("NK ester ATMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.)-Photoinitiator ("Irgacure 907" manufactured by Ciba Geigy) 4 parts ・ Sensitizer (Hoabaya Chemical Co., Ltd. “EAB-F”) 2 parts ・ Cyclohexanone 166 parts

[Production of color filter]
A color filter was prepared in the following manner using the obtained red colored resin composition, blue colored resin composition, and green colored resin composition. As the green colored resin composition, those using the green colored resin compositions 1 to 3, and Examples 1 to 3 and those using the green colored resin compositions 4 to 6 were compared with Comparative Examples 1 to 3. did.

The red colored resin composition was applied on a glass substrate by spin coating so as to have a film thickness of 2 μm. After drying, striped pattern exposure was performed with an exposure machine, and development was performed with an alkali developer for 90 seconds. Subsequently, post-baking was performed in an oven at 210 ° C. for 30 minutes to form red pixels, which are striped colored layers, on a transparent substrate. The alkaline developer has the following composition. In the following examples and comparative examples, development was performed using this alkaline developer.
<Allcali Developer>
・ Sodium carbonate 1.5% by mass
・ Sodium bicarbonate 0.5% by mass
・ Anionic surfactant (“Perirex NBL” manufactured by Kao Corporation) 8.0% by mass
・ 90% by mass of water

  Next, each of the green colored resin compositions 1 to 6 is similarly applied by spin coating so that the film thickness becomes 2 μm, dried, and then the striped colored layer is shifted from the above-mentioned red pixel by an exposure machine. The green pixel adjacent to the above-mentioned red pixel was formed by exposing to a spot and post-baking after development.

  Further, in the same manner as red and green, a blue pixel adjacent to the red pixel and the green pixel was formed with a film thickness of 2 μm for the blue colored resin composition. Thus, color filters of Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 having red, green, and blue stripe-like pixels on a transparent substrate were obtained.

Regarding the color filters of Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3, the content of the polymerizable resin and the acrylic resin of the green coloring composition used for the production of the color filter, and the green color of each color filter Table 1 shows the values of chromaticity y and dielectric loss tangent at a pixel thickness of 1.5 μm. FIG. 5 shows a plot of the relationship between the amount of transparent resin contained in the green composition and the dielectric loss tangent. The value at 20 Hz was used as the representative value for the dielectric loss tangent.

<Comparison result>
As shown in Table 1, in the color filter of Example 1, when the content of the polymerization composition in the green colored layer is 22%, the chromaticity y of the green pixel is 0.580 and the dielectric loss tangent is 0.023. I was able to. In the color filter of Example 2, when the content of the polymerization composition in the green colored layer was increased to 27%, the dielectric loss tangent decreased to 0.020, but the chromaticity value became 0.570. . Furthermore, in the color filter of Example 3, when the content of the polymerization composition in the green colored layer was 17%, the chromaticity y of the green pixel was 0.588 and the dielectric loss tangent was 0.025.
On the other hand, in the case of the color filter of Comparative Example 1 containing 27% of the polymer composition in the green colored layer used in the color filter of Example 2 instead of acrylic resin, the chromaticity value y of the green pixel is 0.570 was shown, but the dielectric loss tangent was 0.029, and the target value could not be satisfied. Further, like the color filter of Comparative Example 2, when the amount of the acrylic resin contained in the green colored layer is increased to 53%, the dielectric loss tangent is 0.025, but the chromaticity value y is 0.484, The target hue could not be met. Further, as in the color filter of Comparative Example 3, when the content of the polymerization composition of the green colored layer is 16%, the chromaticity value y is 0.059, but the dielectric loss tangent is 0.026, which is the target. The dielectric loss tangent could not be satisfied.

  Pixel electrodes having slits were provided in the color filters of Examples 1, 2, and 3 and the color filters of Comparative Examples 1, 2, and 3 to produce MVA liquid crystal display devices. In the liquid crystal display device using the color filter, a good display quality was obtained without causing the liquid crystal alignment defect of the pixel and the threshold shift of the driving voltage. In contrast, in the liquid crystal display devices using the color filters of Comparative Examples 1, 2, and 3, image sticking occurred due to poor liquid crystal alignment and switching threshold shift, and good display characteristics could not be obtained.

3C-PS ... Color laminated photo spacer 10 ... Color filter 11, 21 ... Transparent substrate (glass substrate)
12 ... Colored layer 13, 22 ... Pixel electrode 14 ... Slit
17 ... Insulating dot pattern 20 ... Opposite substrate 23a, 23b ... Projection

Claims (5)

In a color filter comprising a pixel electrode having at least a red pixel, a green pixel, and a blue pixel on a transparent substrate, and a slit provided on each pixel,
The dielectric loss tangent (tan δ) of the colored layer constituting the green pixel is 0.025 or less in the frequency range of 10 Hz to 100 Hz, the thickness of the colored layer of the green pixel is 1.0 μm to 3.0 μm, and the green pixel The chromaticity y at a film thickness of 1.5 μm is 0.57 or more, and the green coloring composition of the green pixel is reacted with styrene and an unsaturated carboxylic acid-containing monomer as at least a transparent resin. A color composition comprising a polymer composition having a mass average molecular weight of 30,000 or less, a solid content acid value of 10 to 150 mgKOH / g, and a styrene content of 75 mol% or more and less than 95 mol%, and a copper halide phthalocyanine pigment filter. When a slit is provided in the pixel electrode on each pixel by photoetching, the pixel electrode portion on the color laminated photospacer formed of the colored layer formed simultaneously with the formation of the green pixel, the red pixel, and the blue pixel is The color filter according to claim 1 , wherein the color filter is removed simultaneously by etching. The color filter dielectric constant of the colored layer of each pixel, as claimed in any one of claims 1-2, characterized in that more than 5.0 in the frequency range of 10Hz～100Hz. Wherein on the color layer of each pixel, not through the protective layer, a slit is provided pixel electrode provided, according to claim 1 to 3 in which the colored layer from the slit, characterized in that it is exposed to the liquid crystal holding surface The color filter according to any one of the above. The liquid crystal display device characterized by comprising a color filter according to any one of claims 1-4.

Images