JP2011118033A - Color filter and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter of which the thickness-direction retardation value of a red coloring pixel layer is controlled to be negative, and for which optical compensation is adequately performed even when an identical optical compensation film is used. <P>SOLUTION: The color filter is formed of a cured product of a red coloring composition which contains an organic compound having a planar structural group and an organic compound having one or more crosslinking groups as retardation adjusting agents for the purpose of making retardation of a red pixel at a wavelength of 620 nm negative, wherein each of the organic compounds is selected from one or more of organic compounds selected from a styrene compound and its polymerizable compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a color filter that optimizes a thickness direction retardation of a red colored pixel, and a liquid crystal display device that is provided with the color filter and that is compensated for a phase difference.

  The liquid crystal display device is a display element that utilizes the birefringence of liquid crystal molecules, and includes a liquid crystal cell, a polarizing element, and an optical compensation layer. Liquid crystal display devices are roughly classified into two types according to the type of light source: a transmission type that has a light source inside and a reflection type that uses an external light source. The transmissive liquid crystal display device has a configuration in which polarizing elements are attached to both sides of a liquid crystal cell, and one or two optical compensation layers are disposed between the liquid crystal cell and the polarizing element. In the reflective liquid crystal display device, the reflector, the liquid crystal cell, one optical compensation layer, and one polarizing element are arranged in this order.

  In a liquid crystal cell, rod-like liquid crystal molecules sandwiched between two substrates are aligned and sealed, and a voltage is applied to an electrode layer formed on both or one of the substrate surfaces in contact with the liquid crystal. In other words, the light-transmission / light-shielding mechanism is switched by changing the alignment state of the rod-like liquid crystal molecules.

  The liquid crystal cell is different in the alignment state of rod-like liquid crystalline molecules, TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensated Bend), STN (Supper Twisted Nematic). VA (Vertically Aligned) and HAN (Hybrid Aligned Nematic) types.

  Various optical compensation layers have been proposed. For example, in a VA (vertical alignment) mode liquid crystal display device capable of high-contrast display, the optical axis is perpendicular to the substrate and negative birefringence is different. A phase difference film having a directivity (negative C plate) and a phase difference film having a positive birefringence anisotropy (positive A plate) are used in combination.

  In recent years, liquid crystal display devices have been evaluated for their space-saving, light-weight, and power-saving properties due to their thinness. There is a strong demand to further improve display performance.

  Specifically, normally black mode IPS and VA liquid crystal display devices capable of higher contrast and wide viewing angle display are particularly preferred for TV applications, and the above-described optical compensation layer is often used. However, most of them are designed to have an optimum value so as to minimize the color at the time of black display when viewed from the front and the color shift when viewed from an oblique direction.

Since the retardation of the color filter was relatively small compared to the polarizing element, the liquid crystal itself, the alignment film, and the protective layer used in the liquid crystal display device, this problem has not been emphasized so far. However, it has become a level that cannot be ignored in liquid crystal televisions that require high contrast and wide viewing angle characteristics.
In particular, a liquid crystal display device with a high contrast of 2,000 or 5,000 is required to have a high required black display image quality, and retardation of the color filter itself has become a problem.

Normally, the optical design is centered on green, so if the retardation (hereinafter referred to as Rth (R), Rth (G), and Rth (B)) of the red, blue, and green colored pixel layers is significantly different, the leakage light As a result, a problem arises in oblique visibility. Usually, red and blue optical compensation is performed using an optical compensation layer that exhibits monotonous wavelength dispersion with respect to the wavelength of light with respect to the green wavelength. In the optical compensation layer having this characteristic, compensation should be made. If the thickness direction retardation value for each color is too uneven (including positive and negative), it will not be possible to compensate at the level of advanced display quality that is required recently. Therefore, it is desirable to satisfy the relationship of Rth (R) <Rth (G) <Rth (B) or Rth (R)> Rth (G)> Rth (B) because optical compensation is facilitated.

  However, in the case of PG36, which is a general-purpose pigment, 0> Rth (G), and in the case of PB15: 6, which is a blue pigment, Rth (B)> 0, so the current situation is Rth (B)> 0> Rth (G) It becomes. Since red light has a longer wavelength than green light, it is necessary to satisfy the relationship 0> Rth (G)> Rth (R) so that the corresponding Rth (R) also decreases monotonously. In many cases, Rth (R)> 0, and it is difficult to satisfy the relationship of Rth (B)> 0> Rth (G)> Rth (R). Therefore, it can be said that a red pigment capable of satisfying Rth (R) <0 is demanded for red colored pixels.

For this, a birefringence-reducing particle having a birefringence opposite to that of the polymer in the film containing the color pigment, or containing a polymer having a planar structure group in the film containing the color pigment. Attempts have been made to reduce the amount of retardation of the color filter by containing (for example, Patent Documents 1 and 2).
However, the thickness direction retardation value of the color filter varies greatly depending on the type of pigment used, the influence of fineness or dispersion of the pigment, or the influence of matrix resin (for example, acrylic resin or cardo resin). The present inventors have found that a sufficient effect cannot be obtained only by the method including these polymer thin film and birefringence reducing particles, and Rth (R) cannot be made negative.

JP 2000-187114 A JP 2008-185985 A

  Therefore, in the present invention, when the thickness direction phase differences of the red colored pixel, the green colored pixel, and the blue colored pixel are respectively expressed as Rth (R), Rth (G), and Rth (B), this is expressed as Rth (R) <Rth. An object of the present invention is to provide a color filter that reliably satisfies the relationship (G) <Rth (B).

  In the color filter in which red pixels, green pixels, and blue pixels are arranged on a transparent substrate, the red pixels are formed from a cured product of a colored composition having negative retardation. This is a color filter characterized by

  The invention according to claim 2 is a color filter characterized in that the red coloring composition contains an organic compound having a planar structure group as a retardation adjusting agent.

  The invention according to claim 3 is a color filter characterized in that the red coloring composition contains a compound having one or more crosslinkable groups as a retardation adjusting agent.

The invention according to claim 4 is a color filter characterized in that the organic compound is an organic compound selected from one or more selected from a styrene compound and a polymerizable compound thereof.

The invention according to claim 5 is the color filter according to any one of claims 1 to 4, wherein the styrene compound is an organic compound represented by the following chemical formula. is there.

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

As described above, according to the present invention,
By making the thickness direction phase difference of the red colored pixel negative, it becomes possible to monotonously decrease the thickness direction phase difference of the blue colored pixel, the green colored pixel, and the red colored pixel in this order. Therefore, in a liquid crystal panel provided with a color filter composed of these colored pixels, phase difference compensation can be easily performed by externally attaching a phase difference compensation film to the panel.
Further, in the liquid crystal display device including the color filter and the retardation compensation film, the variation in the polarization state of the light passing through the display area of each colored pixel is Rth (R) <Rth (G) <Rth (B). Reduced display device that is not colored not only in the viewing direction (normal direction) of the display surface but also in viewing from an oblique direction deviated by about 45 degrees from the viewing direction, and has good front (display surface normal direction) visibility It becomes.

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

  Hereinafter, embodiments of the present invention will be described.

  First, the thickness direction retardation value of each colored pixel layer is a phase difference measuring device such as a spectroscopic ellipsometer in a color filter having at least three colored pixels of red (R), green (G) and blue (B). Note that it is obtained by measuring the three-dimensional refractive index using.

For example, a phase difference measurement is performed with light from at least two directions of the front surface and an incident angle of 45 degrees at a wavelength of 620 nm for a red color pixel, 550 nm for a green color pixel, and 450 nm for a blue color pixel, and Nx, Ny, Nz 3 After obtaining the dimensional refractive index, the thickness direction retardation value (Rth) is calculated from Equation 1 shown below.
Rth = {(Nx + Ny) / 2−Nz} × d (Formula 1)
In the formula, Nx and Ny are the refractive indexes in the x and y directions in the colored pixel surface, respectively, and Nz is the refractive index in the thickness direction. d is the thickness (nm) of the colored pixel layer. Here, the positive birefringence anisotropy is a case where Nx satisfies N _Z ≧ Nx = Ny, and since Rth <0 from Equation 1 above, negative retardation is exhibited.

At this time, when the substrate to be measured is a color filter, the phase difference value for each colored pixel layer is measured by using a mask processed so as to transmit only the single colored pixel layer of R, G, and B. Can be requested.
That is, when light having a wavelength of 620 nm is used as incident light, a phase difference value caused only by a red colored pixel, and, in the case of 550 nm, a phase difference value caused by only a green colored pixel, 450 n
In the case of m, the approximate value of the single colored pixel layer can be estimated as the phase difference value caused only by the blue colored pixels.
In addition, when the substrate to be measured is a single colored pixel layer of R, G, or B (a configuration in which a coating film of a monochrome color filter coloring composition is formed on a transparent substrate), without using a mask The phase difference can be measured.

Next, the retardation adjusting agent will be described.
The retardation adjusting agent is a material added to adjust the phase difference in the thickness direction of the color filter when the color filter coloring composition is formed as a colored coating on a transparent substrate, a reflective substrate, or a semiconductor substrate. That is. In particular, for the purpose of improving oblique visibility, if necessary, it can be added to a color filter coloring composition of two or more colors.
The compound used as the retardation adjusting agent is preferably an organic compound with good dispersibility in order to ensure a high contrast of 1000 or 3000 or more. Particle shapes such as inorganic substances can also be used, but they should be avoided from the viewpoint of light scattering and depolarization.

The retardation adjusting agent described below is an organic substance that has the possibility of making retardation negative by adding it to a coloring composition (or red coloring composition) in which an organic pigment is dispersed in a transparent resin or transparent resin precursor described later. It is.
The retardation adjusting agent made of an organic substance has a planar structure group and has one or more aromatic rings. In monocyclic hydrocarbons, a phenyl group, cumenyl group, mesityl group, tolyl group, xylyl group, benzyl group , Styrene group, phenethyl group, styryl group, cinnamyl group, trityl group, etc., polycyclic hydrocarbons such as pentarenyl group, indenyl group, naphthyl group, biphenylene group, acenaphthylene group, fluorene group, phenanthryl group, anthracene group, triphenylene group, Known compounds such as a pyrene group, a naphthacene group, a pentaphen group, a pentacene group, a tetraphenylene group, and a trinaphthylene group can be used. For heteromonocyclic compounds, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, triazine group, etc.For heteropolycyclic compounds, indolizinyl group, isoindolyl group, indolyl group, purinyl group, quinolyl group, isoquinolyl group, phthalazinyl Groups, naphthyridinyl groups, quinoxalinyl groups, cinolinyl groups, carbazolyl groups, carbolinyl groups, acridinyl groups, porphyrin groups, and the like, which have substituents such as hydrocarbon groups and halogen groups. Also good.

  The at least one crosslinkable group attached to the planar structure group is preferably an unsaturated polymerizable group, a functional group, or a thermally polymerizable group, and an epoxy group is more preferably used.

Further, the unsaturated polymerizable group is more preferably an ethylenically unsaturated polymerizable group, and —CH ₂ NHCOCH═CH ₂ , —CH ₂ NHCO (CH ₂ ) ₇ CH═CH (CH ₂ ) ₇ CH ₃ , —OCO (C ₆ H ₄ ) O (CH ₂ ) ₆ CH═CH _{2 and the} like are also preferably used.

  These crosslinkable groups have glycidyl (meth) acrylate, 2- (meth) acryloyloxyisocyanate, tolylene-2,4-diisocyanate when the planar structural group has at least one reactive functional group such as a hydroxyl group. It can be easily obtained by reacting a compound having an ethylenically unsaturated group with a functional group that reacts with the above reactive functional group by a known method.

  In the present invention, as a result of studying the compound as a retardation adjusting agent, the styrene compound was found to have a positive birefringence anisotropy by relaxing film shrinkage in a red colored pixel in the heating stage, and Rth (R) <0 was found.

  Next, the color filter according to the present invention will be described.

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

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

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 147, 151, 152, 153, 154, 155, 156, 161 162,164,166,167,168,169,170,171,172,173,174,175,176,177,179,180,181,182,187 188,193,194,199,198,213,214, and the like. Examples of the orange pigment include C.I. I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73 and the like.

When the red pixel contains one or more of diketopyrrolopyrrole red pigments and anthraquinone red pigments among these pigments, it is preferable because any Rth can be easily obtained. This is because the diketopyrrolopyrrole red pigment can be made positive or negative and the absolute value thereof can be controlled to some extent by devising the finer treatment, and the anthraquinone red pigment is This is because it is easy to obtain Rth close to 0 regardless of the miniaturization process.
The amount used is 10 to 90% by weight of the diketopyrrolopyrrole red pigment and 5 to 70% by weight of the anthraquinone red pigment based on the total weight of the pigment. From the viewpoint of contrast and the like, in particular, when focusing on the contrast, it is more preferable that the diketopyrrolopyrrole red pigment is 25 to 75% by weight and the anthraquinone red pigment is 30 to 60% by weight.

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

  In the above, examples of the diketopyrrolopyrrole red pigment include C.I. I. Pigment Red 254 and an anthraquinone red pigment include C.I. I. Pigment Red177, an azo metal complex yellow pigment, such as C.I. I. Pigment Yellow 150 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

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

  The pigment contained in the colored pixel is preferably miniaturized and preferably has a small average primary particle size in order to achieve high brightness and high contrast of the color filter. The average primary particle diameter of the pigment can be calculated by taking the pigment with a transmission electron microscope and analyzing the image of the photograph.

  The average primary particle diameter of the pigment is preferably 40 nm or less, more preferably 30 nm or less, and still more preferably 20 nm or less. Moreover, it is preferable that an average primary particle diameter is 5 nm or more. When the average primary particle diameter of the pigment is larger than the upper limit value, the visibility of the liquid crystal display device during black display is poor. Moreover, when smaller than a lower limit, pigment dispersion | distribution becomes difficult, it becomes difficult to maintain stability as a coloring composition and to ensure fluidity | liquidity. As a result, the luminance and color characteristics of the color filter are deteriorated. In particular, an organic pigment having an average primary particle diameter exceeding 40 μm adversely affects front visibility.

  In addition, each color pixel formed on the transparent substrate is sandwiched between two polarizing plates, a backlight is applied from one polarizing plate side, and the light transmitted through the other polarizing plate is measured with a luminance meter. The contrast C calculated from the ratio of the light luminance (Lp) in the parallel state and the light luminance (Lc) in the orthogonal state is calculated from C = Lp / Lc, CS is only the substrate without colored pixels, and CR is When red pixel, CG represents green pixel, and CB represents blue pixel contrast, CR / CS> 0.45, CG / CS> 0.45, and CB / CS> 0.45, The front visibility at the time of black display of the liquid crystal display device is excellent.

  Means for controlling the average primary particle diameter and thickness direction retardation of the pigment include a method in which the pigment is mechanically pulverized to control the primary particle diameter and particle shape (called a grinding method), and a solution in a good solvent. A method in which a pigment having a desired primary particle size and particle shape is deposited by introducing it into a poor solvent (referred to as a precipitation method), and a method for producing a pigment having a desired primary particle size and particle shape at the time of synthesis (referred to as a synthetic precipitation method) ) Etc. Depending on the synthesis method and chemical properties of the pigment to be used, an appropriate method can be selected for each pigment.

  Each method will be described below, and any of the above methods may be used as a method for controlling the primary particle diameter and particle shape of the pigment contained in the colored pixel layer constituting the color filter of the present invention.

  In the grinding method, the pigment is mechanically kneaded using a ball mill, sand mill or kneader together with a grinding agent such as water-soluble inorganic salt such as salt and a water-soluble organic solvent that does not dissolve it. This is a method of obtaining a pigment having a desired primary particle size and particle shape by washing and removing the inorganic salt and the organic solvent, followed by drying. However, since the pigment may crystallize by the salt milling treatment, a method of preventing crystal growth by adding a solid resin or a pigment dispersant that is at least partially dissolved in the organic solvent during the treatment is effective.

As for the ratio of the pigment to the inorganic salt, if the ratio of the inorganic salt is increased, the efficiency of refining the pigment is improved, but the productivity is lowered because the amount of pigment processed is reduced.
In general, 1 to 30 parts by weight, preferably 2 to 20 parts by weight of the inorganic salt is used per 1 part by weight of the pigment. The water-soluble organic solvent is added so that the pigment and the inorganic salt are uniformly solidified. Although depending on the blending ratio of the pigment and the inorganic salt, the water-soluble organic solvent is usually added in an amount of 0.1% by weight with respect to 1 part by weight of the pigment. Used in an amount of 5 to 30 parts by weight.
More specifically, with respect to the above grinding method, a small amount of a water-soluble organic solvent is added as a wetting agent to a mixture of a pigment and a water-soluble inorganic salt, and after kneading with a kneader or the like, the mixture is poured into water. Stir with a speed mixer to make a slurry. Next, this slurry is filtered, washed with water, and dried to obtain a pigment having a desired primary particle size and particle shape.

The precipitation method is a method in which a pigment is dissolved in an appropriate good solvent and then mixed with a poor solvent to precipitate a pigment having a desired primary particle size and particle shape. The type and amount of the solvent, the precipitation temperature, and the precipitation rate. The primary particle size and particle shape can be controlled by the above.
In general, pigments are difficult to dissolve in solvents, so the solvents that can be used are limited, but examples include strongly acidic solvents such as concentrated sulfuric acid, polyphosphoric acid, chlorosulfonic acid, or basic solvents such as liquid ammonia, dimethylformamide solution of sodium methylate, etc. It has been known.

A typical example of this method is an acid pasting method in which a solution in which a pigment is dissolved in an acidic solvent is poured into another solvent and reprecipitated to obtain fine particles. Industrially, a method of injecting a sulfuric acid solution into water is generally used from the viewpoint of cost.
The sulfuric acid concentration is not particularly limited, but is preferably 95 to 100% by weight. The amount of sulfuric acid used with respect to the pigment is not particularly limited. However, if the amount is too small, the solution viscosity is high and handling becomes bad. Conversely, if the amount is too large, the treatment efficiency of the pigment is lowered. It is preferable.
The pigment need not be completely dissolved. The temperature at the time of dissolution is preferably from 0 to 50 ° C. Below this temperature, sulfuric acid may freeze and the solubility will be low. If the temperature is too high, side reactions tend to occur.
The temperature of the water to be injected is preferably 1 to 60 ° C., and if the injection is started at a temperature higher than this temperature, it boils with the heat of dissolution of sulfuric acid, and the operation is dangerous. It will freeze at temperatures below this. The injection time is preferably 0.1 to 30 minutes with respect to 1 part of the pigment. As the time increases, the primary particle size tends to increase.

The primary particle size and particle shape of the pigment can be controlled while considering the size adjustment of the pigment by selecting a method that combines a precipitation method such as the acid pasting method and a grinding method such as the salt milling method. Further, it is more preferable because the fluidity as a dispersion can be secured at this time.
During salt milling or acid pasting, in order to prevent aggregation of pigments accompanying primary particle size and particle shape control, the following pigment derivatives, resin type pigment dispersants, surfactants and other dispersing aids may be used in combination. it can. Further, by controlling the primary particle size and particle shape in the form of coexistence of two or more pigments, even a pigment that is difficult to disperse alone can be finished as a stable dispersion.

  There is a leuco method as a special precipitation method. When a vat dye, such as a flavantron, perinone, perylene, or indanthrone, is reduced with alkaline hydrosulfite, the quinone group becomes a hydroquinone sodium salt (leuco compound) and becomes water-soluble. A pigment having a small primary particle size insoluble in water can be precipitated by adding an appropriate oxidizing agent to the aqueous solution for oxidation.

The synthetic precipitation method is a method in which a pigment having a desired primary particle size and particle shape is precipitated simultaneously with the synthesis of the pigment. However, when the produced fine pigment is taken out of the solvent, if the pigment particles are not aggregated into large secondary particles, filtration, which is a general separation method, becomes difficult. It is applied to azo pigments synthesized in water.

  Furthermore, as a means for controlling the primary particle size and particle shape of the pigment, the primary particle size of the pigment is reduced by dispersing the pigment for a long time with a high-speed sand mill or the like (so-called dry milling method in which the pigment is dry pulverized). It is also possible to disperse at the same time.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  FIG. 2 is a schematic cross-sectional view of a liquid crystal display device provided with the color filter of the present invention. A device 4 shown in FIG. 2 is a typical example of a TFT drive type liquid crystal display device for a notebook personal computer, and includes a pair of transparent substrates 5 and 6 disposed so as to be opposed to each other. (LC) is enclosed.

  In the present invention, liquid crystal in a liquid crystal alignment mode such as TN (Twisted Nematic), STN (Super Twisted Nematic), IPS (In-Plane Switching), VA (Vertical Alignment), OCB (Optically Compensated Birefringence) can be applied.

  A TFT (thin film transistor) array 7 is formed on the inner surface of the first transparent substrate 5, and a transparent electrode layer 8 made of, for example, ITO is formed thereon. An alignment layer 9 is provided on the transparent electrode layer 8. Further, on the outer surface of the transparent substrate 5, a polarizing plate 10 including a retardation film is formed.

  On the other hand, the color filter 11 of the present invention is formed on the inner surface of the second transparent substrate 6. The red, green and blue filter segments constituting the color filter 11 are separated by a black matrix (not shown). A transparent protective film (not shown) is formed so as to cover the color filter 11, and further, a transparent electrode layer 12 made of, for example, ITO is formed thereon. Is provided. A polarizing plate 14 is formed on the outer surface of the transparent substrate 6. A backlight unit 16 including a three-wavelength lamp 15 is provided below the polarizing plate 10.

  As described above, according to the present embodiment, in order to obtain a color filter with higher contrast, by specifying the pigment type to be used or by making the pigment finer, red, green, and Even if there is a possibility that the thickness direction retardation value of the blue colored pixel layer changes to unevenness, light is emitted to at least one planar structure group and at least two different parts of the planar structure group. By using a retardation adjusting agent having a polymerizable group or a thermally polymerizable group, it is possible to provide a coloring composition for a color filter that can be adjusted to an optimum value so that the thickness direction retardation value changes monotonously. It becomes.

Further, by forming a color filter coloring composition from the materials described above to produce a color filter, the thickness direction is monotonously in a relationship of Rth (R) <Rth (G) <0 <Rth (B). A color filter in which the phase difference changes can be obtained.
Furthermore, when a liquid crystal display is produced using the color filter of the present invention so as to be suitable for the optical characteristics of the optical compensation layer and other components, particularly the wavelength dispersion characteristics of retardation, it passes through the display area of each colored pixel. Since the polarization state of the light does not vary, a liquid crystal display device excellent in viewing angle display from an oblique direction can be obtained.
Furthermore, since the display is black with the viewing angle compensated from the oblique direction, when viewed from the oblique direction, the color shift can be reduced, and neutral black can be reproduced, exhibiting excellent display characteristics. Can do.

Hereinafter, although an example is given and described about an embodiment of the invention, the present invention is not limited to the following example. Further, since the material used in the present invention is extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light.
In the examples and comparative examples, “parts” means “parts by weight”. The pigment symbol indicates the color index number. For example, “PR254” is “CI Pigment”.
“Red 254” and “PY150” represent “CI Pigment Yellow 150”.

[Red Pigment 1 (R-1)]
As CI red pigment 1, CI Pigment Red 254, “IR GAPHOR RED B-CF” manufactured by Ciba Specialty Chemicals was used.

[Yellow pigment]
“FANCHON FAST YELLOW Y-5688” (CI PIGMENT Yellow 150) manufactured by BAYER is used as yellow pigment 3 (Y-3).

[Yellow Pigment 2 (Y-2)]
160 parts of yellow pigment 1, 1600 parts of sodium chloride, and 270 parts of diethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) were charged into a stainless steel gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 60 ° C. for 15 hours.

  Next, the mixture is poured into about 5 liters of warm water, stirred at a high speed mixer for about 1 hour while being heated to about 70 ° C. to form a slurry, filtered, washed with water, sodium chloride and dierylene glycol. And dried at 80 ° C. for 24 hours to obtain 157 parts of a slut milled pigment (yellow pigment 2).

[Green pigment]
A halogenated copper phthalocyanine green pigment PG36 (“Lionol Green 6YK” manufactured by Toyo Ink Co., Ltd.) was used.

[Blue pigment]
Copper phthalocyanine blue pigment PB15: 6 (“Lionol Blue ES” manufactured by Toyo Ink Co., Ltd.) was used.

[Preparation of pigment dispersion]
20 parts of a mixture of red pigment 1 / yellow pigment 1 = 65/35 (weight ratio) as a colorant, 5 parts of BYK2001 (in terms of solid content) as a dispersant, and 75 parts of propylene glycol monomethyl ether acetate as a solvent are processed by a bead mill. Thus, a pigment dispersion (RP-1) was prepared.

  20 parts of a mixture of red pigment 1 / yellow pigment 2 = 65/35 (weight ratio) as a colorant, 5 parts of BYK2001 (in terms of solid content) as a dispersant, and 75 parts of propylene glycol monomethyl ether acetate as a solvent are processed by a bead mill. Thus, a pigment dispersion (RP-2) was prepared.

As a coloring agent, C.I. I. Pigment green 36 / C.I. I. Pigment Yellow 150 = 50/50 (weight ratio) mixture, 5 parts of Solsperse 24000 as a dispersant (in terms of solid content), and 75 parts of propylene glycol monomethyl ether acetate as a solvent were treated with a bead mill to obtain a pigment dispersion ( GP-1) was prepared.

  As a coloring agent, C.I. I. Pigment Blue 15: 6 / C.I. I. Pigment violet 23 = 96/4 (weight ratio) 20 parts of a mixture, 5 parts of Ajisper PB821 as a dispersant (in terms of solid content), and 75 parts of propylene glycol monomethyl ether acetate as a solvent were treated with a bead mill to obtain a pigment dispersion ( BP-1) was prepared.

  As the styrene-based retardation adjusting material, the retardation adjusting agent for the styrene-maleic acid-based resin having the skeleton shown in FIG. 3 was used.

[Preparation of colored composition (hereinafter referred to as resist)]
Then, finally, a mixture having the composition (weight ratio) shown in Table 1 was uniformly stirred and mixed, and then filtered through a 1 μm filter to obtain each resist.

[Preparation of coating film]
As a substrate, a melt-formed aluminosilicate thin plate glass having a thickness of 0.7 mm was prepared, washed, and then a black matrix was formed on the substrate, and then the pattern forming photoresist was spun. After applying by the coating method and drying under reduced pressure, exposure is performed so that the irradiation dose by the ultraviolet light source becomes 100 mJ / cm ² , and after the exposure, post-baking is performed at a temperature of 230 ° C. and heating time of 60 minutes A red coating film having a thickness of 2 μm was formed.

  Next, measurement results of chromaticity, spectral transmittance, and thickness direction retardation value of each coating film will be described.

[Chromaticity, spectral transmittance]
The chromaticity in the XYZ color system chromaticity diagram was measured using a spectrophotometer (OTSUKA LCF-1100M). Table 2 shows the chromaticity of each color coating film produced from each resist shown in Table 1.

[Thickness direction retardation value Rth]
Thickness direction retardation value is in the range of 400 nm to 700 nm from a direction inclined 45 ° from the normal direction of the substrate on which the coating film is formed using a transmission spectroscopic ellipsometer (“M-220” manufactured by JASCO Corporation). Measurements were made at a wavelength of every 5 nm to obtain an ellipso parameter δ. A retardation value Δ (λ) was calculated from Δ = δ / 360 × λ, a three-dimensional refractive index was calculated using this value, and a thickness direction retardation value (Rth) was calculated from the following equation 1. However, the measurement was performed at a wavelength of 620 nm for red colored pixels.
Rth = {(Nx + Ny) / 2−Nz} × d (Formula 1)
Nx, d, etc. are the values described above, and the slow axis is such that Nx is Nx ≧ Ny.
Table 2 shows the thickness direction retardation value Rth of each color coating film produced from each resist shown in Table 1. From the results in Table 2, in the coating film formed using the colorant composition containing the retardation adjusting agent, the larger the amount of replacing the retardation adjusting agent with the acrylic resin solution, the more the styrene compound is in the red colored pixel in the heating stage. The film contraction was alleviated, positive birefringence anisotropy was developed, and the thickness direction retardation value was negative compared to a coating film formed using a colorant composition containing no retardation adjusting agent.

[Preparation of color filter]
A color filter was produced by combining the color resists shown in Table 1 by the method shown below.

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

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

  Next, a green pixel was similarly formed using a green resist (GR-1), and further a blue pixel was formed using a blue resist (BR-1) to obtain a color filter. The formed film thickness of each color pixel was 2.0 μm.

  A color filter was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-3) to (RR-5).

  A color filter was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-3) to (RR-5).

[Comparative Example 1]
A color filter was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-3) to (RR-1).

[Comparative Example 2]
A color filter was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-3) to (RR-4).

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

On the other hand, a TFT array and a pixel electrode were formed on one surface of another (second) glass substrate, and a polarizing plate was formed on the other surface. The two glass substrates thus prepared face each other so that the electrode layers face each other, and are aligned using spacer beads while keeping the distance between both substrates constant, and the periphery is left so as to leave an opening for injecting the liquid crystal composition. Sealed with a sealant.
A liquid crystal composition was injected from the opening to seal the opening. The polarizing plate was provided with an optimized optical compensation layer. The liquid crystal display device thus produced was combined with a backlight unit to obtain a liquid crystal panel.

[Visibility evaluation during black display of liquid crystal display]
The produced liquid crystal display device is displayed in black, and the amount of light (orthogonal transmitted light; leaked light) leaking from the normal direction (front) of the liquid crystal panel and an orientation (oblique) 45 ° from the normal direction is visually observed. did. The evaluation rank is as follows, and the results are shown in Table 3.

  As shown in Example 1, since a red colorant composition containing a retardation adjusting agent is used, the color filter obtained is used in a liquid crystal display device, so that the visibility in the oblique direction is good. A liquid crystal display device can be obtained.

  In Examples 2 to 3, although the retardation adjusting agent is included, the value of the retardation in the thickness direction is small, so the balance of the retardation in the thickness direction of the red pixel, the green pixel, and the blue pixel is not good. Deviation occurs and visibility is poor. Further, in the color filters obtained from Comparative Examples 1 and 2, since the red colorant composition containing the retardation adjusting agent is used and not formed, the phase difference in the thickness direction of the red, green, and blue pixels is not formed. Since the balance is not good, color misregistration occurs in an oblique direction, resulting in poor visibility.

  In the case of using styrene as a retardation adjusting agent, it was discovered that it is necessary to replace the entire amount of acrylic resin in consideration of thermal shrinkage in the thickness direction.

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

Claims (6)

  In a color filter in which a red pixel, a green pixel, and a blue pixel are arranged on a transparent substrate, the red pixel is formed from a cured product of a red coloring composition having a negative retardation at a wavelength of 620 nm. Characteristic color filter.   2. The color filter according to claim 1, wherein the red coloring composition contains an organic compound having a planar structure group as a retardation adjusting agent.   The color filter according to claim 1, wherein the red coloring composition is an organic compound having one or more crosslinkable groups as a retardation adjusting agent.   The color filter according to any one of claims 1 to 3, wherein the organic compound is an organic compound selected from one or more selected from a styrene compound and a polymerizable compound thereof. The color filter according to any one of claims 1 to 4, wherein the styrene compound is an organic compound represented by the following chemical formula.

  A liquid crystal display device using the color filter according to claim 1.

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