JP2009180783A - Liquid crystal display device and color filter for use in it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device, having high contrast and improved in oblique visibility and front visibility. <P>SOLUTION: This liquid crystal display device includes (a) a color filter having at least red, green and blue display pixels on a substrate, and (b) an optical compensation layer provided inside two sheet polarizers, wherein the retardation values RR<SB>th</SB>, GR<SB>th</SB>and BR<SB>th</SB>in the thickness direction of the red display pixel, the green display pixel and the blue display pixel of the color filter and the retardation values R<SB>th</SB>(R), R<SB>th</SB>(G) and R<SB>th</SB>(B) in the thickness direction in a red region, a green region and a blue region of the optical compensation layer satisfy the following expressions (1) to (3). (1)¾RR<SB>th</SB>+R<SB>th</SB>(R)¾≤20, (2)¾GR<SB>th</SB>+R<SB>th</SB>(G)¾≤20, (3)¾BR<SB>th</SB>+R<SB>th</SB>(B)¾≤20. RR<SB>th</SB>, GR<SB>th</SB>and BR<SB>th</SB>respectively indicate the product of a value obtained by subtracting a refractive index in the thickness direction from the average of in-plane refractive indexes of the respective pixels and the thickness (nm) of the pixel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a liquid crystal display device and a color filter used therefor, and more particularly to a liquid crystal display device in which a thickness direction retardation value is optimized.

  A liquid crystal display device uses birefringence based on geometric anisotropy of liquid crystal molecules to control the amount of transmitted light, and is basically composed of a light source, a liquid crystal cell, a polarizing plate, and an optical compensation layer. The Since the liquid crystal is non-luminous, a light source is required, and the liquid crystal is roughly classified into a transmission type liquid crystal display device having a structure incorporating the light source and a reflection type liquid crystal display device using external light. In the transmissive liquid crystal display device, two polarizing plates are provided on both sides of the liquid crystal cell, and one or two optical compensation layers are provided between the liquid crystal cell and the polarizing plate. In the reflective liquid crystal display device, a reflector, a liquid crystal cell, one optical compensation layer, and one polarizing plate are arranged in this order. In the liquid crystal cell, liquid crystal molecules are aligned and held between opposing substrates, and by applying a voltage to an electrode disposed on the inner surface of the opposing substrate, the alignment state of the liquid crystal molecules is changed to transmit light. It is a mechanism to switch between the state and the light shielding state.

  The liquid crystal cell has a TN (Twisted Nematic) mode, an IPS (In-Plane Switching) mode, a FLC (Ferroelectric Liquid Crystal), an OCB (Optically Compensated) depending on how the orientation of the liquid crystal molecules changes from the initial alignment state with voltage application. It has a configuration corresponding to one of operation display modes called a bend mode, an STN (supplier twisted nematic) mode, a VA (vertically aligned) mode, and a HAN (hybrid aligned nematic) mode.

  The polarizing plate is generally produced by diffusing iodine into polyvinyl alcohol and then drawing it to obtain a polarizing film, which is sandwiched from both sides by a transparent triacetyl cellulose film (hereinafter referred to as TAC).

Several types of optical compensation layers have been developed according to the above operation display mode. However, in the IPS mode with good display characteristics in the high viewing angle portion according to the present invention, the refractive index ellipsoid has a main axis direction. to the refractive index _{n x, n y, n z} , n x ≧ n biaxial retardation film characteristics satisfying _y ≧ n _z is desirable effect disclosed (non-patent Document 1). In addition, two biaxial λ / 2 wavelength plates with different _nz sizes are used to compensate for each other's wavelength dispersion, thereby reducing the light leakage in the visible light region in black display and reducing the field of view. An angular IPS liquid crystal display device is also taught (Non-Patent Document 2).

  In recent years, liquid crystal display devices have been favored for space saving and power saving due to their lightness and thinness, and at the same time they are rapidly expanding as large televisions, and at the same time, with respect to display performance such as brightness, contrast, and visibility in all directions. The sophistication is required.

For these requirements, normally black mode IPS and VA mode liquid crystal display devices with high black density when no voltage is applied (high contrast) and capable of wide viewing angle display are particularly suitable. Thus, the optical compensation layer has the refractive indices _nx , _ny , and _nz so that the color shift when viewed black from the front and the color shift when viewed obliquely are minimized. Is set.

The optical compensation layer used in IPS mode liquid crystal display device, as described above, with n _x ≧ n _y ≧ n _z is a biaxial retardation film or n _x ≒ n _y ≒ n _z A film of TAC or the like in which a certain optical compensation function is almost negligible, and when these films are used, the thickness direction retardation _Rth is positive and in the range of 100 or less. Further, in the IPS mode liquid crystal display device, since the liquid crystal molecules only rotate within the substrate surface and do not cause a phase difference in the thickness direction, the thickness direction retardation of these biaxial retardation films is a light leakage. This causes the display characteristics viewed from an angle especially during black display. That is, when viewed from an oblique direction, the black display is tinted yellow or blue, resulting in a negative effect on visibility.

In addition, regarding the thickness direction retardation (hereinafter referred to as R _th (R), R _th (G), R _th (B)) of the red, green and blue colored pixel layers constituting the color filter, When they are different from each other, coloring is observed during black display when viewed from an oblique direction. Since the thickness of the colored pixel layer is determined based on the demand for spectral characteristics as a television, it is practically difficult to make the thickness direction phase difference the same only by changing the thickness.

In particular, the thickness direction retardation value of the colored pixel layers of red, green, and blue does not change monotonously with respect to the wavelength, that is, R _th (R) <R _th (G)> R _th (B) or R _th ( R)> R _th (G) <R _th (B), such as an upward convex or downward convex relationship, a combination with an optical compensation layer that exhibits monotonous wavelength dispersion with respect to the wavelength is Optical compensation cannot be performed at the required high display quality level. Specifically, the visibility from the front (vertical direction) with respect to the display surface is good, but in a visibility from 45 degrees such as 45 degrees (hereinafter referred to as oblique visibility), only a specific color leaks light. By doing so, colors such as reddish, bluedish, greenish, etc. are produced during black display.

  Since the retardation of the color filter was relatively small, this problem has not been regarded as important so far, but 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 high-contrast liquid crystal display device having a high contrast of 1000 or 3000 is required to have a high-quality black display image quality, and there is a need to study the color filter retardation.

For these problems, for films such as TAC, it includes the development of low retardation TAC film for controlling to almost zero by adding such particles to reduce the R _th (e.g., Patent Document 1). However, as a practical problem, there still remains a problem that a slight positive phase difference remains without being completely zero. Moreover, these low retardation TAC films require a special processing technique and have a serious problem that they are expensive.

  On the other hand, a polymer having a planar structure group is bonded to a side chain of a matrix resin (for example, acrylic resin or cardo resin) constituting a colored pixel, or a birefringence index opposite to that of the matrix polymer in the matrix resin. Attempts to reduce the retardation value of a color filter by dispersing birefringence-reducing particles having a characteristic are disclosed (for example, Patent Documents 2 and 3). However, since a correlation with a TAC film or the like is not considered, a satisfactory effect is not obtained.

  Further, even in a color filter that uses a highly transparent acrylic resin as a matrix for a high-contrast liquid crystal display device, it can be viewed obliquely while maintaining the required high contrast value (1000 or more, more preferably 3000 or more). It was difficult to improve sex.

As described above, the necessity of improving the visibility has been recognized, and the means has been studied, but as a result of assuming that a color filter having a small thickness direction retardation is an excellent color filter, The optimization of the thickness direction phase difference of each color to a level where there is no problem in black display is not considered until there is a solution other than the solution that the thickness direction phase difference should be set small. It was.
JP 2006-249328 A JP 2000-136253 A JP 2000-187114 A Ishibe et al., SID Digest, 1094 pages. 2000 Ishibe et al., Jpn. J. et al. Appl. Phys. 41, 4553, 2002

  Under such circumstances, the present inventors have determined that the thickness direction retardation value of the color filter depends on the difference in the matrix resin used (for example, acrylic resin or cardo resin) or the pigment dispersed in them. In addition, it has been found that it also depends on the degree of pigment miniaturization.

  The present invention has been made in view of such a current situation, and the subject is based on the above knowledge and the thickness direction retardation value and optical compensation of the red colored pixel layer, the green colored pixel layer, and the blue colored pixel layer. By considering the thickness direction retardation value of the layer as a whole, there is no coloration not only in the display surface observation direction (normal direction), but also in observation from an oblique direction deviated by about 45 degrees from the observation direction, And it is providing the liquid crystal display device provided with the color filter with favorable front (display surface normal line direction) visibility, especially the liquid crystal display device of IPS mode.

The invention according to claim 1 is a liquid crystal display device including at least a transparent substrate, a color filter including at least a red display pixel, a green display pixel, and a blue display pixel, and an optical compensation layer. The thickness direction retardation value RR _{th of} the pixel, the thickness direction retardation value GR _{th of} the green display pixel, the thickness direction retardation value BR _{th of the} blue display pixel, and the thickness direction retardation value R of the red region of the optical compensation layer. _Th (R), the thickness direction retardation value R _th (G) in the green region, and the thickness direction retardation value R _th (B) in the blue region satisfy the following expressions (1) to (3). This is a liquid crystal display device.
Formula (1): | RR _th + R _th (R) | ≦ 20
Formula (2): | GR _th + R _th (G) | ≦ 20
Formula (3): | BR _th + R _th (B) | ≦ 20
(RR _th , GR _th , and BR _th are numerical values obtained by multiplying the product of the average refractive index in the plane of each pixel by the thickness direction refractive index and the pixel thickness (μm) by 1000). Represent each.)
According to a second aspect of the present invention, the thickness direction retardation value RR _{th of} the red display pixel, the thickness direction retardation value GR _{th of} the green display pixel, the thickness direction retardation value BR _{th of the} blue display pixel, and the optical The thickness direction retardation value R _th (R) in the red region of the compensation layer, the thickness direction retardation value R _th (G) in the green region, and the thickness direction retardation value R _th (B) in the blue region are expressed by the following equations: The liquid crystal display device according to claim 1, wherein (4) to (5) are satisfied.
Formula (4): | RR _th + R _th (R) − (BR _th + R _th (B)) | − | GR _th + R _th (G) − (BR _th + R _th (B)) | ≧ 0
Formula (5): | (RR _th + R _th (R) − (BR _th + R _th (B)) | − | RR _th + R _th (R) − (GR _th + R _th (G)) | ≧ 0
When any one of the above inequality (1) to (5) is satisfied, when viewed from an oblique direction, it is possible to obtain a black display without color shift and color with viewing angle compensation.

A third aspect of the present invention is the liquid crystal display device according to the first or second aspect, wherein the optical compensation layer is a transparent protective film made of triacetyl cellulose (TAC).

  A TAC film is specified as an optical compensation layer that satisfies the inequalities of claims 1 and 2. In addition, a low-cost TAC film can be used as the optical compensation layer.

According to a fourth aspect of the present invention, there is provided a color filter used in the liquid crystal display device according to any one of the first to third aspects, wherein the coloring is included in the red display pixel, the green display pixel, and the blue display pixel of the color filter. The color filter is characterized in that the primary particle diameter d ₅₀ of the pigment is 40 nm or less.

By setting the particle size d ₅₀ of the primary particles of the pigment in the above range, not only from an oblique direction, it can be obtained with good visibility liquid crystal display device from the front direction. The particle diameter d ₅₀ represents a particle diameter (equivalent circle diameter) corresponding to 50% of the total amount in the integrated curve of the number particle size distribution.

 According to a fifth aspect of the invention, the red display pixel is at least one red pigment selected from the group consisting of a diketopyrrolopyrrole red pigment and an anthraquinone red pigment, and the green display pixel is a metal halide phthalocyanine type. At least one green pigment selected from the group consisting of a green pigment, an azo yellow pigment and a quinophthalone yellow pigment, the blue display pixel is at least selected from the group consisting of a metal phthalocyanine blue pigment and a dioxazine purple pigment The color filter according to claim 4, comprising one kind of blue pigment.

 By using these pigments and controlling the primary particle diameter of the pigments, it is possible to change the thickness direction phase difference of each colored display pixel in the positive and negative directions.

 A sixth aspect of the present invention is the liquid crystal display device according to any one of the first to third aspects, wherein the liquid crystal display device is an IPS system.

 As described above, according to the present invention, the thickness direction retardation values of the red, green, and blue colored pixel layers constituting the color filter specify the pigment type that constitutes the colored pixel, and It was found that it can be prepared over a positive or negative value by, for example, refining the pigment. This makes it possible to match each of the colored pixels with the optical phase characteristics of the color filter constituting the liquid crystal display device and the phase characteristics of the other optical members. In particular, in the present invention, as a result of matching the thickness direction retardation of the optical compensation layer and the thickness direction retardation of the color filter, the thickness direction phase value of the color filter has an optimum value in a range different from the conventional prediction. I understood it. Within that range, a liquid crystal display device having a contrast value of 1000 or more, or 3000 or more, and excellent visibility in the oblique direction and the front can be obtained.

  Further, the present invention is adapted to a low-cost TAC film, and can provide a high-quality liquid crystal display device at a low price.

  Hereinafter, the background and the gist of the present invention will be briefly described, and then the embodiments will be described.

  A color filter coloring composition suitable for use in a liquid crystal display device is based on a polymer or monomer such as an acrylic resin or cardo resin, which is easy to ensure high contrast, and at least an organic solvent, a photopolymerizable initiator, or a curing agent. A liquid coating liquid in which a pigment is dispersed.

The retardation of a color filter made of these colored compositions is 0.01 or less in absolute value according to a general method. Further, it has been considered desirable that the thickness direction retardation value R _th is R _th (R) = R _th (G)) = R _th (B) = 0. (Where R, G, and B represent specific wavelengths in the red, green, and blue regions). However, the actual color filter retardation is “a combination in which R _th of the green pixel is larger than the red pixel, but R _th of the blue pixel is smaller than the green pixel” or “ R _th despite the red pixel value smaller than, R _th of the blue pixel is a combination "a green pixel value greater than the optical retardation plate or the like which wavelength dispersion of these and the retardation varies monotonically When the members are combined, good oblique visibility could not be obtained.

In view of this, the present inventor considers the wavelength dispersion of the retardation value of components other than the color filter, for example, TAC film, other than R _th (R) = R _th (G) = R _th (B) = 0. In addition, the inventors have conceived that there is an optimum thickness direction retardation of the color filter. Therefore, first, whether the thickness direction retardation of the colored compositions of red, green, and blue depends on the matrix resin material, the colored pigment, etc. constituting the colored composition, and if it changes, what is the range? We examined in detail.

  As a result, the retardations of the color filter layers composed of the red, green and blue coloring compositions are different, red and blue indicate positive or negative retardation, green indicates negative retardation, and are adjustable. I found out.

Therefore, in the case of biaxial retardation films and TAC films widely used in IPS mode liquid crystal display devices, the thickness direction retardation value of these films is zero or more and has a positive value. it is desirable thickness direction retardation R _t in which colored pixels is a negative value, considering the above results, that it is possible to optimize as such has been suggested.

In practice, the thickness direction retardation R _t needs to be set so as to obtain an optimum oblique visibility in a combination with an optical member such as a liquid crystal, a polarizing plate, an optical compensation layer, and an alignment film. In this example, it is assumed that the retardation of the liquid crystal and alignment film is negligible compared to other members, and the front visibility and oblique visibility are tested by focusing on the combination of the optical compensation TAC film and the thickness direction retardation of the color filter. The optimum range was defined by evaluation.

As a conclusion, regarding the thickness direction retardation of the TAC film and the color filter, when satisfying a certain inequality (Claim 1 and Claim 2), good front visibility and oblique visibility can be achieved. In the case of a color filter composed of a pigment-dispersed coloring composition, in the particle size distribution of primary particles of the pigment, the particle size d ₅₀ corresponding to 50% of the total amount in the integrated curve of the number particle size distribution is 40 nm or less. It is preferable that d ₅₀ is 30 nm or less (Claim 4).

  The red display pixel includes at least one red pigment selected from the group consisting of a diketopyrrolopyrrole red pigment and an anthraquinone red pigment, and the amount used is based on the total amount of the pigment. The diketopyrrolopyrrole red pigment is preferably 0 to 100% by weight and the anthraquinone red pigment is preferably 0 to 66% by weight. Further, the diketopyrrolopyrrole red pigment includes C.I. I. Pigment Red 254, the anthraquinone red pigment includes C.I. I. Pigment Red 177 can be preferably used.

The green display pixel includes at least one green pigment selected from the group consisting of metal halide phthalocyanine-based green pigments, azo-based yellow pigments, and quinophthalone-based yellow pigments. As a reference, it is preferable that the halogenated copper phthalocyanine green pigment is 0 to 100% by weight, and the azo yellow pigment and / or the quinophthalone yellow pigment is 0 to 60% by weight. Further, the halogenated copper phthalocyanine green pigment includes C.I. I. Pigment Green 36, the azo yellow pigment includes C.I. I. Pigment Yellow 150, the quinophthalone yellow pigment includes C.I. I. Pigment Yellow 138 can be preferably used.

 The blue display pixel includes at least one selected from the group consisting of metal phthalocyanine-based blue pigments and dioxazine-based purple pigments, and the amount used is a copper phthalocyanine-based blue pigment based on the total amount of pigments Is 0 to 100% by weight, and the dioxazine-based violet pigment is preferably 0 to 50% by weight. Further, the copper phthalocyanine blue pigment includes C.I. I. Pigment Blue 15: 6, C.I. I. Pigment Violet 23 can be preferably used.

  Hereinafter, the color pigment, the color composition, and the liquid crystal display device related to the color filter will be described in detail, and finally, the reason according to claim 1 and claim 2 will be described with reference to the drawings and tables in the examples. . First, the color filter will be described.

  As shown in FIG. 1, a color filter suitable for use in the liquid crystal display device of the present invention comprises a black matrix 2 as a light shielding layer on a glass substrate 1, and at least red (R) 3 and green (G) 3 'And blue (B) 3 ″ color pixels. 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 pigment and anthraquinone red pigment among these pigments, it is preferable because any _Rth can be easily obtained. This is because, diketopyrrolopyrrole red pigment, by devising the pulverizing treatment, it is also possible to either the R _th positive and negative, also be controlled to some extent its absolute value, addition, anthraquinone red pigment This is because _Rth close to 0 can be obtained without performing a special 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, an anthraquinone red pigment, "C.I. I. Pigment Red
177, examples of the azo metal complex yellow pigment include C.I. I. Pigment Yellow 150 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  For example, C.I. I. Pigment Green 7, 10, 36, 37 or the like can be used, and a yellow pigment can be used in combination. As the yellow pigment, the same pigments as those mentioned for the red pixel can be used.

In a green pixel, it is easy to obtain an arbitrary _Rth by including at least one of a halogenated metal phthalocyanine green pigment, an azo yellow pigment, and a quinophthalone yellow pigment among these pigments. preferable. This is because the halogenated metal phthalocyanine green pigment can control the GR _th to some extent by selecting the central metal, and the azo yellow pigment can convert the positive GR _th to the quinophthalone type regardless of the refining treatment. This is because the yellow pigment can obtain a negative GR _th regardless of the refinement treatment.

The amount used is 30 to 90% by weight of the halogenated metal phthalocyanine green pigment, 5 to 60% by weight of the azo yellow pigment, and 5 to 60% by weight of the quinophthalone yellow pigment based on the total weight of the pigment. This is preferable from the viewpoint of the hue, brightness, and film thickness of the pixel. Furthermore, it is more preferable that the halogenated metal phthalocyanine green pigment is _{50 to} 85% by weight, the azo yellow pigment is 5 to 45% by weight, and the quinophthalone yellow pigment is 5 to 45% by weight.

  In the above, examples of the halogenated metal phthalocyanine green pigment include C.I. I. Pigment Green 7, 36, and zinc halide phthalocyanine pigments and azo yellow pigments include C.I. I. Pigment Yellow 150 and quinophthalone yellow pigments include C.I. I. Pigment Yellow 138 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  Examples of blue pixels include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, and the like can be used, and a purple pigment can be used in combination. Examples of purple pigments include C.I. I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50 and the like.

When the blue pixel contains at least one of a metal phthalocyanine blue pigment and a dioxazine purple pigment among these pigments, it is easy to obtain an _Rth that is close to 0 from negative. The amount used is 40 to 100% by weight of the metal phthalocyanine blue pigment and 1 to 50% by weight of the dioxazine violet pigment based on the total weight of the pigment. It is preferable from a point, Furthermore, it is more preferable to make a metal phthalocyanine blue pigment 50 to 98 weight% and a dioxazine purple pigment 2 to 25 weight%.

  In the above, examples of the metal phthalocyanine blue pigment include C.I. I. Pigment Blue 15: 6, and dioxazine-based purple pigments include C.I. I. Pigment Violet 23 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 oxide (III)), cadmium red, ultramarine, 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 can be calculated by observing the pigment with a transmission electron microscope and analyzing 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 40 nm, the visibility of the liquid crystal display device during black display is poor. On the other hand, when the particle size is smaller than 5 nm, it is difficult to disperse the pigment, and it becomes difficult to maintain the fluidity and maintain the stability as the colored composition. 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 nm adversely affects front visibility.
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. An appropriate method can be selected depending on the synthesis method used, the chemical properties of the pigment, and the like.

 Each method will be described below, and any of these 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 per 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 simultaneously.

Moreover, the retardation adjuster can be added to the color filter coloring composition of one or more colors to the color filter of the present invention, particularly for the purpose of improving oblique visibility. Retardation adjustment is an additive capable of adjusting the thickness direction retardation of a color filter formed as a colored coating film on a transparent substrate, a reflective substrate, or a semiconductor substrate using a color filter coloring composition. The compound used is preferably an organic compound with good dispersibility in order to ensure a high contrast of 1000 or 3000 or more. Specifically, particles in the form of particles, such as inorganic substances, can be used, but it is better to avoid them from the viewpoints of light scattering and depolarization. In addition, when a multi-color filter is formed on a transparent substrate or the like, it may be added to all colors, but it can be added to only one or two colors.

 Specifically, one or more selected from an organic compound having a planar structure group having one or more crosslinkable groups, a melamine resin, a porphyrin compound, and a polymerizable liquid crystal compound may be selected.

  Usually, it is considered that the retardation in the thickness direction of the entire film can be canceled only by adding particles having a planar structure group having birefringence opposite to that of pigment or other resin. However, simply adding particles having a planar structure group will cause the particles themselves to be randomly oriented, and the influence on the thickness direction retardation of the entire film will be small. As a result of intensive investigations, the present inventors have found that by providing at least one crosslinkable group of the planar structure group, the thickness direction retardation of the entire film is greatly changed and exhibits a sufficient effect. It was. That is, for example, by having a functional group that crosslinks in the photo-curing process or photo-curing process in the photolithography process, the planar structural group does not rotate freely, and the planar structural group is more susceptible to shrinkage during thermal curing. By being easily oriented and fixed in the same direction, the function of phase difference control can be effectively expressed.

  As the planar structural group, it has at least one aromatic ring, and in the case of monocyclic hydrocarbon, phenyl group, cumenyl group, mesityl group, tolyl group, xylyl group, benzyl group, phenethyl group, styryl group, In the case of polycyclic hydrocarbons such as cinnamyl and trityl, pentarenyl, indenyl, naphthyl, biphenylene, acenaphthylene, fluorene, phenanthryl, anthracene, triphenylene, pyrene, naphthacene, pentaphen, pentacene Known compounds such as a group, a tetraphenylene group, and a trinaphthylene group can be used. Heterocyclic compounds such as pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, and triazine groups, such as indolizinyl, isoindolyl, indolyl, purinyl, quinolyl, isoquinolyl, and 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 includes an unsaturated polymerizable group (A, B, C, D, E, F) or a functional group (I, J, K, L, M, _N , O) or a thermally polymerizable group (G, H, P, Q, R, S, T, U) is preferable, and an epoxy group (G, H) is more preferably used. ~ U is most preferably used. Further, the unsaturated polymerizable group is more preferably an ethylenically unsaturated polymerizable group (A, B, C, D), and —CH 2 NHCOCH═CH 2, —CH 2 NHCO (CH 2) 7 CH═CH (CH 2). 7CH3, -OCO (C6H4) O (CH2) 6CH = CH2 and the like are also preferably used. These crosslinkable groups are glycidyl (meth) acrylate, 2- (meth) acryloyloxyisocyanate, tolylene-2, 4-, 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 functional group that reacts with the reactive functional group such as diisocyanate and a compound having an ethylenically unsaturated group by a known method.

As the melamine compound, a commercially available compound represented by the following general formula (6) can be preferably used, but any compound having the above-mentioned planar structure group may be used, and a known compound can be used. Examples of melamine compounds are given below.

In the formula, R1, R2, and R3 are a hydrogen atom, a methylol group, an alkoxymethyl group, an alkoxy n-butyl group, and R4, R5, and R6 are a methylol group, an alkoxymethyl group, and an alkoxy n-butyl group, respectively. A copolymer combining two or more kinds of repeating units may be used. Two or more homopolymers or copolymers may be used in combination.

 In addition to the above, compounds having a 1,3,5-triazine ring, for example, those described in JP-A No. 2001-166144 can be used. Further, a compound represented by the following general formula (7) is also preferably used.

R7 to R14 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and particularly preferably a hydrogen atom.

  Alternatively, a compound having a porphyrin skeleton represented by the following general formula (8) can be preferably used. n is an integer of 1 to 20, and 2 is preferably used.

In the formula, each of R15 to R22 is independently a hydrogen atom, a halogen atom, an alkoxy group, an alkylthio group-substituted or unsubstituted phenoxy group, a substituted or unsubstituted naphthoxy group, a substituted or unsubstituted phenylthio group, or a substituted or unsubstituted group Represents a naphthylthio group.

  Specific examples of the porphyrin compound represented by the general formula (8) used in the present invention are described below. Examples of the halogen atom in R15 to R22 include fluorine, chlorine, bromine and iodine. Further, the alkoxy group and the thioalkyl group are not particularly limited, but the alkyl group in the substituent is preferably a linear, branched or cyclic alkyl group having 1 to 12 carbon atoms, and having 1 to 8 carbon atoms. A linear, branched or cyclic alkyl group is particularly preferred. Z represents -CH2-, -N-.

  Specific examples of the alkyl group in the alkoxy group and thioalkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group. Group, n-pentyl group, iso-pentyl group, 2-methylbutyl group, 1-methylbutyl group, neo-pentyl group, 1,2-dimethylpropyl group, 1,1 dimethylpropyl group, cyclopentyl group, n-hexyl group, 4-methylpentyl group, 3methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2 -Dimethylbutyl group, 1,2-dimethylbutyl group, 1,1-dimethylbutyl group, 3-ethylbutyl group, 2-ethylbutyl group, 1-ethylbutyl Group, 1,2,2-trimethylbutyl group, 1,1,2-trimethylbutyl group, 1-ethyl-2-methylpropyl group, cyclohexyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl Group, 4-methylhexyl group, 5 methylhexyl group, 2,4-dimethylpentyl group, n-octyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,5,5-trimethylpentyl group, 2 , 4-dimethylhexyl group, 2,2,4-trimethylpentyl group, n-octyl group, 3,5,5-trimethylhexyl group, n-nonyl group, n-decyl group, 4-ethyloctyl group, 4- Ethyl 4,5-dimethylhexyl group, n-undecyl group, n-dodecyl group, 1,3,5,7-tetraethyloctyl group, 4-butyloctyl group, 6,6-diethyloctyl group Til, n-tridecyl, 6-methyl-4-butyloctyl, n-tetradecyl, n-pentadecyl, 3,5-dimethylheptyl, 2,6-dimethylheptyl, 2,4-dimethylheptyl Group, 2,2,5,5-tetramethylhexyl group, 1-cyclopentyl-2,2-dimethylpropyl group, 1-cyclohexyl-2,2-dimethylpropyl group and the like.

  Specific examples of the substituted or unsubstituted phenoxy group include phenoxy group, 2-methylphenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 2-ethylphenoxy group, 3-ethylphenoxy group, 4-ethyl. Examples include phenoxy group, 2,4-dimethylphenoxy group, 3,4-dimethylphenoxy group, 4-t-butylphenoxy group, 4-aminophenoxy group, 4-dimethylaminophenoxy group, 4-diethylaminophenoxy group and the like.

  Specific examples of the substituted or unsubstituted naphthoxy group include 1-naphthoxy group, 2-naphthoxy group, nitronaphthoxy group, cyanonaphthoxy group, hydroxynaphthoxy group, methylnaphthoxy group, trifluoromethylnaphthoxy group and the like. .

  Specific examples of the substituted or unsubstituted phenylthio group include a phenylthio group, a 2-methylphenylthio group, a 3-methylphenylthio group, a 4-methylphenylthio group, a 2-ethylphenylthio group, and a 3-ethylphenylthio group. Group, 4-ethylphenylthio group, 2,4-dimethylphenylthio group, 3,4-dimethylphenylthio group, 4-t-butylphenylthio group, 4-aminophenylthio group, 4-dimethylaminophenylthio group , 4-diethylaminophenylthio group and the like.

  Specific examples of the substituted or unsubstituted naphthylthio group include 1-naphthylthio group, 2-naphthylthio group, nitronaphthylthio group, cyanonaphthylthio group, hydroxynaphthylthio group, methylnaphthylthio group, trifluoromethylnaphthylthio group. Etc.

  X may be a combination of two or more compounds (for example, a compound having a 1,3,5-triazine ring and a compound having a porphyrin skeleton).

Examples of the plane-containing structural group epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol AD type epoxy compounds, hydrogenated bisphenol A type epoxy compounds and the like; for example, phenol novolak type Epoxy compounds, novolak-type epoxy compounds such as cresol novolak-type epoxy compounds; for example, glycidylamines such as tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, tetraglycidyl-m-xylenediamine Epoxy compounds; for example, glycidyl ester epoxy such as diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate Compounds; for example, triglycidyl isocyanurate, etc. complex Kaeshiki epoxy compounds such as glycidyl glycidoxy Arch setup in can be exemplified.
An example is shown in general formula (9).

As the polymerizable liquid crystal compound, a rod-like liquid crystal molecule or a discotic liquid crystal molecule can be applied, and a discotic liquid crystal molecule is particularly preferable. As the rod-like liquid crystalline molecules, liquid crystalline molecules described in JP-A-2006-16599 can be employed, and other examples include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic esters, cyclohexanecarboxylic acid, and the like. Acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines,
Phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles and the like are also used. As the discotic liquid crystalline molecules, for example, those described in JP-A-8-27284 can be used. An example is shown below.

In the above, Y is an alkylene group, an alkenylene group, an arylene _{group, -CO -, - N H -} , - O -, - S- and divalent linking group selected from the group consisting of, and the two- Most preferably, the group is a combination of at least two valent groups.
The alkylene group preferably has 1 to 12 carbon atoms, the alkenylene group preferably has 2 to 12 carbon atoms, and the arylene group preferably has 6 to 10 carbon atoms. . The alkylene group, alkenylene group and arylene group may have a substituent (eg, alkyl group, halogen atom, cyano, alkoxy group, acyloxy group).
R represents an unsaturated polymerizable group (A, B, C, D, E, F) or a functional group (I, J, K, L, M, N, O) or a thermally polymerizable group (shown in Table 1). At least one crosslinkable group selected from G, H, P, Q, R, S, T, U), or an alkyl group, an alkenyl group, an aryl group, or a heterocyclic group substituted with the crosslinkable group is there. The unsaturated polymerizable group is more preferably an ethylenically unsaturated polymerizable group (A, B, C, D), and —CH 2 NHCOCH═CH 2, —CH 2 NHCO (CH 2) 7 CH═CH (CH 2) 7 CH 3, -OCO (C6H4) O (CH2) 6CH = CH2 or the like is also preferably used.

  Next, 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 is 10 to 300 with respect to 100 parts by weight of the pigment in the coloring composition.
It can be used in an amount of parts by weight, preferably 10 to 200 parts by weight.

  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 thereof 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-1 Acetophenone photopolymerization initiators such as -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- Fe Benzophenone photopolymerization initiators such as rubenzophenone, 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 (trichlorome ) -6-styryl s
-Triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -striazine, 2- (4-methoxy-naphth-1-yl) -4,6-bis (trichloromethyl)- Triazine photopolymerization initiators such as s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, and borate photopolymerization initiation Agents, carbazole photopolymerization initiators, imidazole photopolymerization initiators, and the like are 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-trimerca DOO -s- triazine, 2- _{(N, N} - dibutylamino) -4,6-dimercapto -s- triazine. 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 Le triethoxysilane, _N-beta (aminoethyl) .gamma.-aminopropyl methyl diethoxy silane, .gamma.-aminopropyltriethoxysilane, .gamma.-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 the 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 are formed on the transparent substrate by using the above-described color coloring 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 colored pixel by the printing method can be patterned simply by repeating the printing and drying of the colored composition prepared as the above various printing inks. Therefore, the color filter manufacturing method is low cost and excellent in mass productivity. ing. Furthermore, it is possible to print a fine pattern having high dimensional accuracy and smoothness by the development of printing technology. In order to perform printing, it is preferable that the ink does not dry and solidify on the printing plate or on the blanket. Control of ink fluidity on a printing press is also important, and ink viscosity can be adjusted with a dispersant or extender pigment.

  The ink jet method is a method in which an ink jet apparatus having a plurality of fine discharge ports (ink jet heads) for each color is directly printed on a transparent substrate or a substrate on which an active element such as a TFT is formed.

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.
The dried film is exposed to ultraviolet rays through a mask having a predetermined pattern provided in contact with or non-contact with the film. Then, after immersing in a solvent or alkali developer or spraying the developer by spraying or the like to remove the uncured portion to form a desired pattern, the same operation is repeated for other colors to produce a color filter. be able to. Furthermore, in order to accelerate the polymerization of the colored resist, heating can be performed as necessary. According to the photolithography method, a color filter with higher accuracy than the above printing method can be manufactured.

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

  A color filter suitable for use in the liquid crystal display device 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 will be described.

  FIG. 2 is a schematic cross-sectional view of a liquid crystal display device provided with a color filter. The liquid crystal display device 4 is a typical example of a TFT drive type liquid crystal display device for a liquid crystal television, and includes a pair of transparent substrates 5 and 6 which are disposed to be opposed to each other, and a nematic liquid crystal is enclosed between them. Has been. The liquid crystal has an alignment state corresponding to the IPS mode. 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 an optical compensation layer is formed.

  On the other hand, the color filter 11 by the photolithography method described above 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, but see FIG. 1). The color filter 11 is covered with a transparent protective film (not shown) as necessary, and further, a transparent electrode layer 12 made of, for example, ITO is formed thereon, and an alignment layer 13 that covers the transparent electrode layer 12 is provided. It has been. A polarizing plate 14 is attached to 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.

  Hereinafter, specific examples using the members and configurations described above will be described. In the examples and comparative examples, “parts” means “parts by weight”. The symbol of the pigment indicates a color index number. For example, “PR254” represents “CI Pigment Red 254” and “PY150” represents “CI Pigment Yellow 150”. Table 2 shows the dye derivatives used.

(A) Production of refined pigments The refined pigments used in Examples and Comparative Examples were prepared by the following method. Then, the obtained pigment was observed with a transmission electron microscope (“JEM-1200EX” manufactured by JEOL Ltd.), and the primary particle diameter of the pigment was calculated by image analysis. The primary particle diameter referred to here represents a particle diameter (equivalent circle diameter) corresponding to 50% of the total amount in the cumulative curve of the number particle size distribution.

[Preparation Example 1]
100 parts of diketopyrrolopyrrole red pigment PR254 ("Irgafoa Red B-CF" manufactured by Ciba Specialty Chemicals; R-1), 18 parts of dye derivative (D-1), 1000 parts of crushed salt, and 120 parts of diethylene glycol Was charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 60 ° C. for 10 hours. The mixture was added to 2000 parts of warm water, heated to about 80 ° C. and stirred with a high speed mixer for about 1 hour to form a slurry, filtered and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. Dried to obtain 115 parts of salt milled pigment (R-2).
Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 2]
100 parts of anthraquinone red pigment PR177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals), 8 parts of a dye derivative (D-2), 700 parts of crushed salt, and 180 parts of diethylene glycol are made of 1 gallon kneader made of stainless steel (Inoue Seisakusho) And kneaded at 70 ° C. for 4 hours.
The mixture was put into 4000 parts of warm water, heated to about 80 ° C., stirred with a high speed mixer for about 1 hour to form a slurry, filtered and washed with water to remove salt and solvent, and then at 80 ° C. for 24 hours. Dried to obtain 102 parts of a salt milled pigment (R-3). Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 3]
A sulfonation flask is charged with 170 parts of tert-amyl alcohol under a nitrogen atmosphere. 11.04 parts of sodium were added and the mixture was heated to 92-102 ° C.
The molten sodium was kept at 100-107 ° C. overnight with vigorous stirring. A solution prepared by dissolving 44.2 parts of 4-chlorobenzonitrile and 37.2 parts of diisopropyl succinate in 50 parts of tert-amyl alcohol at 80 to 98 ° C. was dissolved in the obtained solution. Introduced over 2 hours. After the introduction, the reaction mixture is stirred for a further 3 hours at 80 ° C. and at the same time 4.88 parts of diisopropyl succinate are added dropwise.
The reaction mixture is cooled to room temperature and added to a 20 ° C. mixture of 270 parts of methanol, 200 parts of water, and 48.1 parts of concentrated sulfuric acid and stirring is continued at 20 ° C. for 6 hours.
The red mixture is filtered and the residue is washed with methanol and water and then dried at 80 ° C.
46.7 parts of a red pigment (R-4) were obtained. Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 4]
120 parts of halogenated copper phthalocyanine green pigment PG36 (“Lionol Green 6YK” manufactured by Toyo Ink Co., Ltd.), 1600 parts of crushed salt, and 270 parts of diethylene glycol were charged into a 1 gallon kneader (manufactured by Inoue Seisakusho) at 70 ° C. And kneaded for 12 hours.
The mixture was poured into 5000 parts 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 and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 117 parts of salt milling pigment (G-1).
Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 5]
In a molten salt of 200 ° C. of 356 parts of aluminum chloride and 6 parts of sodium chloride, 46 parts of zinc phthalocyanine was dissolved, cooled to 130 ° C., and stirred for 1 hour. The reaction temperature was raised to 180 ° C., and bromine was added dropwise at 10 parts per hour for 10 hours. Thereafter, chlorine was introduced at 0.8 parts per hour for 5 hours. The reaction solution was gradually poured into 3200 parts of water, then filtered and washed with water to obtain 107.8 parts of a crude zinc halide phthalocyanine pigment. The average number of bromine contained in one molecule of the crude zinc halide phthalocyanine pigment was 14.1 and the average number of chlorine was 1.9. 120 parts of the obtained crude zinc halide phthalocyanine pigment, 1600 parts of crushed salt and 270 parts of diethylene glycol were charged into a stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 70 ° C. for 12 hours.
The mixture was poured into 5000 parts 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 and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 117 parts of salt milling process pigments (G-2).
Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 6]
A separable flask was charged with 150 parts of water, and further stirred with 63 parts of 35% hydrochloric acid to prepare a hydrochloric acid solution. While paying attention to foaming, 38.7 parts of benzenesulfonyl hydrazide was charged, and ice was added until the liquid temperature became 0 ° C. or lower. After cooling, 19 parts of sodium nitrite was charged over 30 minutes, stirred for 30 minutes at 0 to 15 ° C., and then sulfamic acid was charged until no coloration was observed on the potassium iodide starch paper.
Furthermore, after adding 25.6 parts of barbituric acid, it heated up to 55 degreeC and stirred as it was for 2 hours.
Furthermore, 25.6 parts of barbituric acid was added, and after raising the temperature to 80 ° C., sodium hydroxide was added until the pH reached 5.
After further stirring for 3 hours at 80 ° C., the temperature was lowered to 70 ° C., followed by filtration and washing with warm water. The obtained press cake was reslurried in 1200 parts of warm water, and then stirred at 80 ° C. for 2 hours. Thereafter, filtration was performed at the same temperature, and washing with 2000 parts of water at 80 ° C. was performed with warm water, and it was confirmed that benzenephonamide was transferred to the filtrate side. The obtained press cake was dried at 80 ° C. to obtain 61.0 parts of disodium azobarbituric acid.
Next, 200 parts of water was charged into a separable flask, and 8.1 parts of the obtained disodium azobarbituric acid powder was added and dispersed while stirring. After uniformly dispersing, the solution was heated to 95 ° C., and 5.7 parts of melamine and 1.0 part of diallylaminomelamine were added. Further, a green solution obtained by dissolving 6.3 parts of cobalt (II) chloride hexahydrate in 30 parts of water was added dropwise over 30 minutes. After completion of the dropwise addition, complexation was performed at 90 ° C. for 1.5 hours.
Thereafter, the pH was adjusted to 5.5, and then 2 parts of xylene, 0.4 part of sodium oleate, and 16 parts of water were pre-stirred to add 20.4 parts of the emulsion, and further heated and stirred for 4 hours. did. After cooling to 70 ° C., it is quickly filtered and 70 ° C. until the inorganic salt can be washed.
Repeated warm water washing. Thereafter, 14 parts of an azo yellow pigment (Y-2) was obtained through drying and pulverization steps. Table 3 shows the primary particle diameter of the obtained pigment.

[Preparation Example 7]
100 parts of copper phthalocyanine-based blue pigment PB15: 6 (“Rionol Blue ES” manufactured by Toyo Ink Manufacturing Co., Ltd.), 800 parts of crushed salt and 100 parts of diethylene glycol were charged into a 1 gallon kneader (manufactured by Inoue Seisakusho) at 70 ° C. And kneaded for 12 hours. The mixture was poured into 3000 parts 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 and washed repeatedly to remove salt and solvent, and then at 80 ° C. for 24 hours. It dried and obtained 98 parts of salt milling pigment (B-1). Table 3 shows the primary particle diameter of the obtained pigment.

(B) Preparation of acrylic resin solution 800 parts of cyclohexanone was placed in a reaction vessel, heated to 100 ° C. while injecting nitrogen gas into the vessel, and a mixture of the following monomer and thermal polymerization initiator was added at the same temperature over 1 hour. The polymerization reaction was performed dropwise.

Styrene 60.0 parts Methacrylic acid 60.0 parts Methyl methacrylate 65.0 parts Butyl methacrylate 65.0 parts Azobisisobutyronitrile 10.0 parts After dropwise addition, the mixture was further reacted at 100 ° C for 3 hours, and then azo A solution in which 2.0 parts of bisisobutyronitrile was dissolved in 50 parts of cyclohexanone was added, and the reaction was further continued at 100 ° C. for 1 hour to synthesize a resin solution.
After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the nonvolatile content, and cyclohexanone was added to the previously synthesized resin solution so that the nonvolatile content was 20%. An acrylic resin solution was prepared.

(C) Preparation of pigment dispersion A mixture having the composition (weight ratio) shown in Table 4 was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using zirconia beads having a diameter of 1 mm, and then filtered through a 5 μm filter. Thus, each color pigment dispersion was obtained.

(D) Retardation adjuster The following commercially available compounds were used as retardation adjusters.
Melamine compound ・ ・ ・ Nippon Carbide Industries (trade name Nikarak MX-750)
Polymerizable liquid crystal (LC)

(E) Preparation of colored composition (hereinafter referred to as resist) Next, a mixture having the composition (weight ratio) shown in Table 5 was uniformly stirred and mixed, and then filtered through a 1 μm filter to obtain each color resist.

(F) Production of color filter A color filter was produced by the method shown below by combining the color resists shown in Table 5.
[Example 1]
First, a red resist (RR-5) was applied to a glass substrate on which a black matrix had been formed in advance by spin coating, 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-4), and further a blue pixel was formed using a blue resist (BR-3) to obtain a color filter. The formed film thickness of each color pixel was 2.0 μm.

(G) Measurement of chromaticity, spectral transmittance, thickness direction retardation value, and contrast of each color coating film
[Chromaticity, spectral transmittance]
The chromaticity in the XYZ color system chromaticity diagram was measured using a spectrophotometer ("OSP-200" manufactured by Olympus). Table 6 shows the chromaticity of each color coating film prepared from each color resist shown in Table 5.

[Thickness direction retardation value R _th ]
The thickness direction retardation value of each color pixel layer of the color filter is determined by the color filter including the color pixels 3 of three colors of red (R), green (G), and blue (B) in the visible region (for example, the wavelength of light). Continuous light including a wavelength in the transmitted light peak region (ranging from 380 nm to 780 nm) was irradiated from the front and a plurality of inclined angles, and measured using a phase difference measuring device such as a spectroscopic ellipsometer. Moreover, the thickness direction retardation value of films, such as TAC, was also measured by the same method.

Specifically, using a transmission-type spectroscopic ellipsometer (“M-220” manufactured by JASCO Corporation), every 5 nm in the range of 400 nm to 700 nm from the direction inclined 45 ° from the normal direction of the substrate on which the coating film is formed. Δ, which is an ellipso parameter, was obtained.
Δ = δ / 360 × λ is used to calculate a retardation value Δ (λ), and using this value, a three-dimensional refractive index is calculated, and a thickness direction retardation value (R _th ) is calculated from the following equation (6). Calculated. However, measurement was performed at a wavelength of 610 nm for a red colored pixel, 550 nm for a green colored pixel, and 450 nm for a blue colored pixel.
(Expression 6): R _th = {(n _x + _ny ) / 2−n _z } × d
Wherein, n _x is a refractive index in the x-direction in the plane of the color pixel layer, n _y is a refractive index in the y direction in the plane of the color pixel layer, n _z is a refractive the thickness direction of the color pixel layer a rate, a slow axis of the n _x and n _x ≧ n _y. d is the thickness (nm) of the colored pixel layer. Table 6 shows the thickness direction retardation value _Rth of each color coating film prepared from each color resist shown in Table 5.

[contrast]
A polarizing plate was placed on both sides of the substrate on which the coating film was formed, and the ratio of luminance (Lp) when the polarizing plate was parallel and luminance (Lc) when it was orthogonal, Lp / Lc was calculated as contrast (C).
Luminance was measured using a color luminance meter ("BM-5A" manufactured by Topcon Corporation) under the condition of a 2 ° field of view. Iodine was diffused into the TAC film and PVA as a transparent protective film on the polarizing plate. A stretched polarizing film, an optical compensation layer, and an adhesive layer for attaching to a glass substrate were used.
Table 6 shows the contrast of each color coating film prepared from each color resist shown in Table 5.

(H) Preparation of liquid crystal display device On the color filter prepared in (f), a transparent ITO electrode layer was formed by a conventional method, and a polyimide alignment layer was formed thereon. A polarizing plate was formed on the other surface of this glass substrate. Furthermore, a TFT array and a pixel electrode were formed on another glass substrate, and a polarizing plate having a structure of a TAC film, a polarizing film, a TAC film, and an adhesive layer was attached to the back surface. The two glass substrates face each other so that the electrode layers face each other, and are aligned using spacer beads while keeping the distance between the two glass substrates constant, and the periphery is sealed so as to leave an opening for injecting the liquid crystal composition. Sealed with a stopper. Next, a liquid crystal composition was injected from the opening, and then the opening was sealed.
The polarizing plate was provided with an optical compensation layer capable of displaying a wide viewing angle. The thickness direction retardation value of this optical compensation layer is 37 μm at 450 nm (R _th (B)), 42 μm at 550 nm (R _th (G)), and 51 μm at 630 nm (R _th (R)). there were. The liquid crystal display device thus produced was combined with a backlight unit to obtain a liquid crystal panel.

[Example 2]
A liquid crystal display device was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-5) to (RR-6) and the green resist was changed from (GR-4) to (GR-5). .

[Comparative Example 1]
Other than replacing the red resist from (RR-5) to (RR-1), the green resist from (GR-4) to (GR-1), and the blue resist from (BR-3) to (BR-1) Obtained a liquid crystal display device in the same manner as in Example 1.

[Comparative Example 2]
Other than changing the red resist from (RR-5) to (RR-2), the green resist from (GR-4) to (GR-3), and the blue resist from (BR-3) to (BR-1) Obtained a liquid crystal display device in the same manner as in Example 1.

[Comparative Example 3]
A liquid crystal display device was obtained in the same manner as in Example 1 except that the red resist was changed from (RR-5) to (RR-3) and the blue resist was changed from (BR-3) to (BR-2). .

[Comparative Example 4]
Other than changing the red resist from (RR-5) to (RR-4), the green resist from (GR-4) to (GR-2), and the blue resist from (BR-3) to (BR-2) Obtained a liquid crystal display device in the same manner as in Example 1.

[Comparative Example 5]
A liquid crystal display device was obtained in the same manner as in Example 1 except that the green resist was changed from (GR-4) to (GR-5) and the blue resist was changed from (BR-3) to (BR-2). .

(J) Visibility evaluation at the time of black display of the liquid crystal display device The produced liquid crystal display device is displayed in black, and leaks from the normal direction (front) of the liquid crystal panel and from the direction (oblique) inclined by 45 ° from the normal direction. The amount of light (orthogonal transmitted light; leakage light) was visually observed.
The evaluation rank is sensory evaluation of ○ (excellent), Δ (good), and × (possible). Table 7 shows the results.

As is apparent from Table 7, in Example 1 and Example 2, the thickness direction retardation value of the red color pixel, the green color pixel, and the blue color pixel layer of the color filter and the corresponding value of the optical compensation layer are as follows: Any one of the formulas (1) to (3) according to claim 1 and the formulas (4) to (5) according to claim 2 is satisfied, and in this case, black display including oblique visibility is achieved. Visibility was good.

  Further, in the liquid crystal display device provided with the color filter of Example 1 and Example 2, as shown in Table 6, since high contrast is achieved at the front, the liquid crystal display with good visibility also in the front direction. It is a device. On the other hand, in the liquid crystal display device including the color filter obtained from Comparative Examples 1 to 5, the thickness direction retardation value of the red color pixel, the green color pixel, and the blue color pixel layer and the corresponding value of the optical compensation layer are Since none of the similar expressions is satisfied, the balance of the phase difference in the thickness direction of the red pixel, the green pixel, and the blue pixel is poor, and color misregistration occurs in the oblique direction, resulting in poor visibility.

  From the above results, the effectiveness of claims 1 and 2 was shown.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Black matrix 3 ... Red coloring pixel 3 '... Green coloring pixel 3''... Blue coloring pixel 4 ... Liquid crystal display device 5, 6 ... Transparent substrate 7 ... TFT array 8, 12 ... Transparent electrodes 9, 13 ... Alignment layer 10, 14 ... Polarizing plate (including optical compensation layer)
11 ... Color filter 15 ... Three-wavelength lamp 16 ... Backlight unit

Claims (6)

In a liquid crystal display device including at least a transparent substrate, a color filter including at least a red display pixel, a green display pixel, and a blue display pixel, and an optical compensation layer, the thickness direction retardation value RR _th of the red display pixel of the color filter. , Thickness direction retardation value GR _{th of} the green display pixel, thickness direction retardation value BR _{th of the} blue display pixel, thickness direction retardation value R _th (R) in the red region of the optical compensation layer, thickness in the green region A liquid crystal display device, wherein the direction retardation value R _th (G) and the thickness direction retardation value R _th (B) in the blue region satisfy the following expressions (1) to (3).
Formula (1): | RR _th + R _th (R) | ≦ 20
Formula (2): | GR _th + R _th (G) | ≦ 20
Formula (3): | BR _th + R _th (B) | ≦ 20
(RR _th , GR _th , and BR _th represent the product of the value obtained by subtracting the refractive index in the thickness direction from the average in-plane refractive index of each pixel and the thickness (nm) of the pixel, respectively). The thickness direction retardation value RR _{th of} the red display pixel, the thickness direction retardation value GR _{th of} the green display pixel, and the thickness direction retardation value BR _{th of the} blue display pixel, and the thickness direction position in the red region of the optical compensation layer The phase difference value R _th (R), the thickness direction retardation value R _th (G) in the green region, and the thickness direction retardation value R _th (B) in the blue region are expressed by the following equations (4) to (5). The liquid crystal display device according to claim 1, wherein the liquid crystal display device is satisfied.
Formula (4): | RR _th + R _th (R) − (BR _th + R _th (B)) | − | GR _th + R _th (G) − (BR _th + R _th (B)) | ≧ 0
Formula (5): | (RR _th + R _th (R) − (BR _th + R _th (B)) | − | RR _th + R _th (R) − (GR _th + R _th (G)) | ≧ 0   The liquid crystal display device according to claim 1, wherein the optical compensation layer is a transparent protective film made of triacetyl cellulose (TAC). A color filter used in the liquid crystal display device according to any one of claims 1 to 3, wherein the particles are primary particles of a color pigment contained in a red display pixel, a green display pixel, and a blue display pixel of the color filter. a color filter, wherein the size d ₅₀ is 40nm or less.
(The particle diameter d ₅₀ represents the particle diameter (equivalent circle diameter) corresponding to 50% of the total amount in the integrated curve of the number particle size distribution).  The red display pixel is at least one red pigment selected from the group consisting of a diketopyrrolopyrrole red pigment and an anthraquinone red pigment, and the green display pixel is a metal halide phthalocyanine green pigment, an azo yellow pigment. And at least one green pigment selected from the group consisting of quinophthalone yellow pigments, the blue display pixel is at least one blue pigment selected from the group consisting of metal phthalocyanine blue pigments and dioxazine purple pigments, The color filter according to claim 4, which is contained.   The liquid crystal display device according to claim 1, wherein the liquid crystal display device is an IPS system.