JP2012088475A - Color filter and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-contrast liquid crystal display device showing no coloring even when the display is observed in an oblique direction and having good frontal visibility, and to provide a color filter for the display device.SOLUTION: The color filter for a liquid crystal display device includes color pixels comprising at least a red pixel, a yellow pixel, a green pixel and a blue pixel, in which a retardation value Rth(R) in a thickness direction of the red pixel, a retardation value Rth(Y) in a thickness direction of the yellow pixel, a retardation value Rth(G) in a thickness direction of the green pixel and a retardation value Rth(B) in a thickness direction of the blue pixel satisfy expression (1):Rth(R)<Rth(Y)<Rth(G)<Rth(B) or expression (2):Rth(B)<Rth(G)<Rth(Y)<Rth(R).

Description

  The present invention relates to a color filter with good visibility in an oblique direction and a front surface, and a liquid crystal display device including the color filter.

  The liquid crystal display device is a display element that utilizes the birefringence of liquid crystal molecules, and includes a liquid crystal cell, a polarizing element, and an optical compensation layer. Such a liquid crystal display device is roughly classified into a transmission type having a light source inside and a reflection type having a structure using an external light source, depending on the type of light source.

  The transmissive liquid crystal display device has a configuration in which two polarizing elements are arranged on both sides of a liquid crystal cell, and one or two optical compensation layers are provided between the liquid crystal cell and the polarizing element. The reflective liquid crystal display device has a configuration in which a reflector, a liquid crystal cell, one optical compensation layer, and one polarizing element are arranged in this order.

  In the liquid crystal cell, rod-like liquid crystal molecules sandwiched between two substrates are aligned and sealed, and a voltage is applied to the electrode layers disposed on both sides or one side of the two substrates, thereby producing a rod-like liquid crystal. This is a mechanism for switching light transmission / light-shielding by changing the orientation state of the active molecule.

  A liquid crystal cell is different in the alignment state of rod-like liquid crystalline molecules, and is composed of TN (Twisted Nematic), IPS (In-Plane Switching Crystal), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensated BirefringN). Various display modes such as VA (Vertical Alignment) and HAN (Hybrid Aligned Nematic) have been proposed.

  The polarizing element generally has a configuration in which two transparent protective films made of triacetyl cellulose (hereinafter referred to as TAC) are attached to both sides of a polarizing film obtained by diffusing iodine into polyvinyl alcohol (hereinafter referred to as PVA). Have

  Various optical compensation layers have been proposed. For example, in a VA mode liquid crystal display device having good display characteristics in a range of a high viewing angle, nx with respect to the three-dimensional main refractive indexes nx, ny, and nz. A biaxial retardation film having a refractive index ellipsoid represented by ≧ ny> nz is also used (see Non-Patent Document 1).

  In recent years, liquid crystal display devices have been evaluated for their space-saving, light-weight, and power-saving properties due to their thinness, and they are rapidly expanding as television viewers, as well as brightness, contrast, and visibility in all directions. There is a strong demand to further improve display performance.

  Specifically, for television applications, normally black mode IPS and VA liquid crystal display devices capable of higher contrast and wide viewing angle display are particularly preferred, and the optical compensation layer described above is also used. Colors that are black when viewed from the front and designed to minimize color changes when viewed from the diagonal are used.

However, the optical compensation layer used in the above-described VA mode liquid crystal display device is generally a biaxial retardation film formed by stretching in the biaxial direction, or is polymerizable liquid crystalline and / or non-polymerized. In most cases, the retardation film is formed by applying a liquid crystalline material, and is controlled at the level of advanced display quality required for the three-dimensional main refractive index nx, ny, nz. It was difficult.

  Specifically, not only the birefringence of the liquid crystal material but also the thickness direction retardation value (hereinafter referred to as Rth (R), Rth (Y)) of the colored pixel layers of red, yellow, green and blue constituting the color filter. , Rth (G), Rth (B)), the three-dimensional main refractive index of the optical compensation layer must be determined and manufactured, but the surface represented by two parameters nx and ny In addition to simultaneously controlling the retardation value in the thickness direction and the retardation value in the thickness direction represented by the three parameters nx, ny, and nz, the wavelength dispersion of the birefringence of the liquid crystal material, and the color filter Optical compensation for wavelength dispersion that compensates for both thickness direction retardation values for red, yellow, green, and blue wavelengths of each colored pixel layer of red, yellow, green, and blue It is difficult to give to the layer , In the conventional liquid crystal display device, not be said to have been designed to yet optimal value.

  As a result, the visibility from the front (vertical direction) with respect to the display surface is good, but the optical observation is not optimally compensated for the visibility observed from an oblique angle such as 45 degrees (hereinafter abbreviated as oblique visibility). Only a specific color leaks light, and colors such as reddish, bluedish, greenish, etc. are generated during black display.

  Compared to other members used in liquid crystal display devices, the retardation of the color filter was relatively small. Therefore, in the conventional liquid crystal display device, the retardation of the color filter is hardly taken into account, and the compensation capability of the optical compensation layer is not considered. However, it has become a level that cannot be ignored in liquid crystal televisions and the like that require high contrast and wide viewing angle characteristics.

  In particular, high-contrast liquid crystal display devices having 1000 or 3000 or more have been required to have a high image quality required for black display. On the other hand, a polymer having a planar structure group is contained in the side chain of the colored polymer thin film, or birefringence reducing particles having a birefringence opposite to that of the polymer are contained in the colored polymer thin film. Attempts have been made to reduce the amount of retardation of the color filter (see Patent Documents 1 and 2).

  In recent years, there has been an increasing demand for color reproducibility close to the real thing, but until now, in the development of color filters with high color reproducibility, there is a trade-off between color purity and brightness, and there is a limit to the range of achievement. there were. As a technique for eliminating this trade-off, development of a multi-primary color display in which Y (yellow) is added to the three primary colors of red, green, and blue is underway. As a result, the color reproduction range can be expanded without impairing the brightness.

  In addition, the in-plane retardation of the blue region of the color filter is made larger than that of the green and red regions, thereby increasing the amount of blue leakage light and offsetting the yellowing that is complementary to blue overall. A method for improving the entire display device from being colored yellow when the display device is viewed obliquely is disclosed (see Patent Document 3).

  Further, the thickness direction retardation values Rth (R), Rth (G), and Rth (B) of the red, green, and blue pixels of the color filter are set to match the wavelength dispersibility of the liquid crystal material or retardation film, and Rth (R). A method of improving oblique visibility by setting> Rth (G)> Rth (B) or Rth (R) <Rth (G) <Rth (B) is disclosed (see Patent Document 4).

However, the thickness direction retardation value of the color filter varies greatly depending on the type of pigment used, and the thickness direction retardation value varies depending on the fineness or dispersion of the pigment or matrix resin (for example, acrylic resin or cardo resin). The present inventors have found that the degree becomes large, and a method including these polymer thin film and birefringence reducing particles cannot obtain a sufficient effect, and cannot solve the above problem.

  In particular, in a color filter using a transparent resin typified by an acrylic resin with good dispersibility of organic pigments for high contrast liquid crystal display devices, the required high contrast value (1000 or more, more preferably 3000 or more) is obtained. It was difficult to improve oblique visibility while maintaining.

  In addition, in the prior art, a color filter with a small birefringence is simply an excellent color filter, and even though a means for improving oblique visibility has been studied, as a high-contrast liquid crystal display device, Considering the wavelength dispersion of the birefringence of the liquid crystal material and the optical compensation layer, there has been little investigation on means for adjusting the thickness direction retardation of each color of the color filter to an optimum value to a level that does not cause a problem with black display. .

JP 2000-136253 A JP 2000-187114 A JP 2001-242460 A JP 2007-212603 A

Ishibe et al., The Society for Information Display Digest, 1094 (2000).

  The present invention has been made under the circumstances as described above, and an object of the present invention is to provide a liquid crystal display device that is not colored even when observed from an oblique direction and has good front visibility and a color filter therefor.

The present invention is for solving the above-mentioned problems, and the invention according to claim 1 of the present invention includes a colored pixel including at least a red pixel, a yellow pixel, a green pixel, and a blue pixel, and the thickness direction of the red pixel. The phase difference value Rth (R), the thickness direction retardation value Rth (Y) of the yellow pixel, the thickness direction retardation value Rth (G) of the green pixel, and the thickness direction retardation value Rth (B) of the blue pixel are expressed by the following formulae. A color filter for a liquid crystal display device, characterized by satisfying (1) and formula (2).
Rth (R) <Rth (Y) <Rth (G) <Rth (B) (1)
Rth (B) <Rth (G) <Rth (Y) <Rth (R) (2)
[Where Rth (R), Rth (Y), Rth (G) and Rth (B) are the values obtained by subtracting the refractive index in the thickness direction from the average in-plane refractive index of each pixel, and the thickness of the pixel ( nm), Rth (R) is a thickness direction retardation value for light of wavelength 610 nm passing through the red region, Rth (Y) is a thickness direction retardation value of light having a wavelength of 580 nm passing through the yellow region, Rth (G) represents a thickness direction retardation value for light having a wavelength of 545 nm passing through the green region, and Rth (B) represents a thickness direction retardation value for light having a wavelength of 450 nm passing through the blue region. ]

The invention according to claim 2 of the present invention is the liquid crystal display device according to claim 1, wherein at least one of the colored pixels is made of a photosensitive coloring composition to which a retardation adjusting agent is added. It is a color filter.

  In the invention according to claim 3 of the present invention, the retardation adjusting agent selects at least one selected from an organic compound having a planar structural group having one or more crosslinkable groups, a melamine compound, and a benzylic compound. The color filter according to claim 2, wherein the color filter is an organic compound.

According to a fourth aspect of the present invention, there is provided a liquid crystal cell comprising the color filter according to the first aspect, polarizing plates respectively disposed on both outer surfaces of the liquid crystal cell, and optical compensation provided inside the polarizing plates. In a liquid crystal display device comprising a layer, the liquid crystal display device is displayed in black, and the chromaticity (u, v) represented by the CIE1960 color system is measured, and the chromaticity (u ( ⊥), v (⊥)) and chromaticity (u (θ), v (θ)) when viewed from the direction inclined by θ ° from the normal direction of the display surface, are expressed by the following formula (3). The liquid crystal display device is characterized in that the chromaticity difference Δuv is 0.02 or less in a range of 0 <θ ≦ 60.
Δuv = [{u (⊥) −u (θ)} 2+ {v (⊥) −v (θ)} 2] 1/2 (3)

  The invention according to claim 5 of the present invention is the liquid crystal display device according to claim 3, which is a VA system or an IPS system.

  According to the present invention, by using the color filter in which the thickness direction retardation value of the green pixel is a positive value and is larger than the thickness direction retardation value of the red pixel and the thickness direction retardation value of the blue pixel, A liquid crystal display device having good visibility in the direction and the front is provided.

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 which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 shows an example of the configuration of a color filter for a liquid crystal display device according to an embodiment of the present invention. A black matrix 2 is provided on a glass substrate 1, and red pixels 3R are formed in regions partitioned by the black matrix 2. Three colored pixels of yellow pixel 3Y, green pixel 3G, and blue pixel 3B are formed.

  In such a color filter, the thickness direction retardation value Rth (R) of the red pixel 3R, the thickness direction retardation value Rth (Y) of the yellow pixel 3Y, the thickness direction retardation value Rth (G) of the green pixel 3G, and The thickness direction retardation value Rth (B) of the blue pixel 3B satisfies the following formula (1) or formula (2).

Rth (R) <Rth (Y) <Rth (G) <Rth (B) (1)
Rth (B) <Rth (G) <Rth (Y) <Rth (R) (2)
(In the formula, Rth (R), Rth (Y), Rth (G) and Rth (B) are values obtained by subtracting the refractive index in the thickness direction from the average in-plane refractive index of each pixel, and the thickness of the pixel ( nm), Rth (R) is the thickness direction retardation value for light of wavelength 610 nm passing through the red region, Rth (Y) is the thickness direction retardation value for light of 580 nm passing through the yellow region, Rth (G) represents the thickness direction retardation value for light having a wavelength of 545 nm passing through the green region, and Rth (B) represents the thickness direction retardation value for light having a wavelength of 450 nm passing through the blue region. The directional phase difference value is obtained by irradiating continuous light including the wavelength of the transmitted light peak region in the visible region (for example, the light wavelength range of 380 nm to 780 nm) from the front and a plurality of inclined angles. It is obtained by measuring the three-dimensional refractive index using a phase difference measuring device.

For example, 610 nm for a red pixel, 580 nm for a yellow pixel, 545 nm for a green pixel, and 450 nm for a blue pixel, and a phase difference measurement using light from at least two directions of the front and an incident angle of 45 degrees. After obtaining the three-dimensional refractive index of Ny and Nz, the thickness direction retardation value (Rth) is calculated by the following equation (4).
Rth = {(Nx + Ny) / 2−Nz} × d (4)
In the formula, Nx is a refractive index in the x direction in the plane of the colored pixel layer, Ny is a refractive index in the y direction in the plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. It is a rate, and the slow axis is set so that Nx is Nx ≧ Ny. d is the thickness (nm) of the colored pixel layer.

  At this time, when the object to be measured is a color filter, the single color pixel layer is measured by measuring through a mask processed so as to transmit only the single color pixel layers of R, Y, G, and B. Can be obtained.

  Further, for example, when light having a wavelength of 610 nm is used as incident light, a phase difference value caused only by a red pixel, in the case of 580 nm, a phase difference value caused only by a yellow pixel, and in a case of 545 nm, a green pixel. In the case of the phase difference value due to only 450 nm, the approximate value of the single colored pixel layer can be estimated as the phase difference value due to only the blue pixel.

  In addition, when the object to be measured is a single colored pixel layer of R, Y, G, or B (a structure in which a coating film of a monochrome color filter coloring composition is formed on a transparent substrate), a mask is used. It is possible to measure the phase difference.

  The thickness direction retardation value of a film such as a biaxial retardation film can be measured by the same method.

  By using the color filter according to an embodiment of the present invention described above for a liquid crystal display device including an optical compensation layer provided inside the polarizing plate respectively disposed on both outer surfaces of the liquid crystal cell, the display surface is vertical. The chromaticity difference between when viewed from the direction and when viewed from the oblique direction can be within a predetermined range, and the variation in the polarization state of the light passing through the display area of each colored pixel of the color filter is reduced. A liquid crystal display device with good visibility in the direction and front can be obtained.

According to the present invention, the chromaticity (u, v) at the time of black display represented by the CIE 1960 color system is measured, and the chromaticity (u (⊥), v (⊥)) when viewed from the vertical direction is displayed. A chromaticity difference Δuv represented by the following expression (3) of chromaticity (u (θ), v (θ)) when viewed from an orientation inclined by θ ° from the normal direction of the surface is expressed as 0 <θ ≦ The liquid crystal display device which is 0.02 or less in the range of 60 can be provided.
Δuv = [{u (⊥) −u (θ)} 2+ {v (⊥) −v (θ)} 2] ^1/2 (3)

  Next, the principle of the liquid crystal display device according to one embodiment of the present invention will be described. The optical compensation layer used in the above-described VA mode liquid crystal display device is generally a biaxial retardation film having a refractive index ellipsoid represented by nx ≧ ny> nz, polymerizable liquid crystal, and / or In most cases, the retardation film is formed by applying a non-polymerizable liquid crystal material, and when these films are used, the thickness direction retardation value Rth usually increases as the wavelength increases. In other words, it has chromatic dispersion (hereinafter referred to as Cauchy's dispersion formula) in which the value increases as the wavelength decreases.

  In general, for VA mode liquid crystal display devices that have both wavelength birefringence and liquid crystal birefringence when viewed obliquely, the Rth wavelength dispersion of these films completely compensates for the wavelength dispersion of the liquid crystal. If not, a problem of deteriorating display characteristics viewed from an angle particularly during black display is caused. That is, when viewed from an oblique direction, the black display adversely affects the yellowish visibility.

  On the other hand, the absolute value of the birefringence of the color filter is 0.01 or less, that is, the thickness direction retardation value (Rth) is unlimited, and Rth (R) = Rth (Y) = Rth (G) = Rth ( B) Although it is generally desired that the value is close to 0, the present inventors have different retardations of the color filter layers of the red, yellow, green, and blue color pixel patterns. For example, red and yellow are positive or negative. It shows retardation, blue has shown the positive retardation, and green has the property which shows a negative retardation.

  As a result, the visibility from the front (vertical direction) with respect to the display surface is good, but only a specific color leaks in the visibility observed from an oblique angle such as 45 degrees (hereinafter referred to as oblique visibility). Therefore, when viewed from an oblique direction during black display, colors such as reddish, yellowish, bluish, or greenish are produced.

  The most desirable value of the retardation value Rth of each colored pixel in the color filter varies depending on the combination with other members, but the biaxial retardation film widely used in the VA mode liquid crystal display device. In this case, since the thickness direction retardation value of these films has a value smaller than the thickness direction retardation value of the liquid crystal, the Rth of the color filter is preferably a positive value.

  More importantly, as the color filter increases in contrast, that is, the depolarization of the color filter decreases, the chromaticity when viewed from the front during black display approaches the chromaticity of the crossed Nicols of the polarizing plate. Is a point.

  The dichroism of the polarizing plate is also improved, and in recent years, a high-contrast polarizing plate has been used, but most of the hues in crossed Nicols are bluish. That is, since there is much light leakage from the polarizing plate at a wavelength around 400 nm, the hue when viewed from the front during black display is bluish.

  Therefore, it is necessary to select a combination that obtains optimal oblique visibility in a combination of optical members of a liquid crystal display device such as a liquid crystal, a polarizing plate, a retardation plate, and an alignment film. In order to minimize the color change at the time, it is necessary to make the chromaticity when viewed obliquely blue.

As a result of intensive studies on these, the present inventors have good continuity in the phase difference so that each color thickness direction retardation value Rth of the color filter satisfies the following formula (1) or formula (2). The present inventors have found that a liquid crystal display device having excellent oblique visibility can be obtained.
Rth (R) <Rth (Y) <Rth (G) <Rth (B) (1)
Rth (B) <Rth (G) <Rth (Y) <Rth (R) (2)
That is, by reducing the retardation value in the thickness direction of the color pixels on the long wavelength side with continuity, the thickness direction retardation value of the color filter has no effect when viewed from the front, and is viewed from an oblique direction. Sometimes, light leakage in the blue region is larger than light leakage in the green region, and the color difference from the front chromaticity can be reduced by being bluish.

Thus, when combined with the wavelength dispersion of a component other than a color filter, for example, a TAC film, an optimum color filter other than Rth (R) = Rth (Y) = Rth (G) = Rth (B) = 0 It has been found that there is a value for the thickness direction retardation.

  Next, a color filter for a liquid crystal display device according to an embodiment of the present invention will be described.

  The color filter shown in FIG. 1 includes four colored pixels of a red pixel 3R, a yellow pixel 3Y, a green pixel 3G, and a blue pixel 3B. However, the color filter is not limited to these four colors, and more than four colors. A color filter of a color may be used.

  In order to obtain good front visibility, particularly a tightened color with low black luminance in black display, when the color display pixel is a color filter formed using a pigment-dispersed coloring composition, the primary color of the pigment. As for the particle size distribution of the particles, the particle size d50 corresponding to 50% of the total amount in the integrated curve of the number particle size distribution is preferably 40 nm or less, and more preferably d50 is 30 nm or less. This is because, when the particle diameter d50 of the primary particles of the pigment is within such a range, a liquid crystal display device having good visibility not only from the oblique direction but also from the front direction can be obtained.

  Examples of red pixels include 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, 187 , 200, 202, 208, 210, 242, 246, 254, 255, 264, 270, 272, 279 and the like, and a yellow pigment and an orange pigment can also be used in combination.

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

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

  When the red pixel contains one or more of diketopyrrolopyrrole red pigments and anthraquinone red pigments among these pigments, it is preferable because any Rth can be easily obtained.

  This is because the diketopyrrolopyrrole red pigment can move Rth in the positive direction by refining the average value of the primary particle diameter of the pigment by devising the refinement treatment, This is because it is possible to bring the Rth in the negative direction by keeping the average value of the coarse, and the absolute value thereof can be controlled to some extent. Also, anthraquinone red pigments are easy to obtain Rth close to 0 regardless of the miniaturization treatment.

  It can be said that the value of Rth almost holds the additive rule depending on the blending ratio of the pigment used. The amount of the pigment used is 0 to 100% by weight of the diketopyrrolopyrrole red pigment, preferably 10 to 90% by weight, and 0 to 80% by weight of the anthraquinone red pigment, preferably 5 based on the total weight of the pigment. -70 wt% is preferable from the viewpoint of the hue, brightness, film thickness, contrast, etc. of the pixel. Especially when focusing on the contrast, 25-75 wt% of diketopyrrolopyrrole red pigment, anthraquinone red More preferably, the 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, it becomes difficult to adjust the hue such as sufficient brightness, 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 Red254 and an anthraquinone red pigment include C.I. I. Pigment Red177, an azo metal complex yellow pigment, such as C.I. I. Pigment Yellow 150 is preferable in terms of excellent light resistance, heat resistance, transparency, coloring power, and the like.

  For example, C.I. I. Green pigments such as Pigment Green 7, 10, 36, 37, and 58 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.

  It is preferable that the green pixel contains at least one of a halogenated metal phthalocyanine green pigment, an azo yellow pigment, and a quinophthalone yellow pigment among these pigments because it becomes easy to obtain an arbitrary Rth. . This is because the halogenated metal phthalocyanine green pigment can control Rth (G) to some extent by selecting the central metal. For example, when the central metal is copper, Rth is a small value. However, when the central metal is zinc, the value of Rth can be made larger than when copper is the central metal. Further, the azo yellow pigment can obtain positive Rth (G) regardless of the refining treatment, and the quinophthalone yellow pigment can obtain negative Rth (G) regardless of the refining treatment.

  Also for the green pixel, it can be said that the Rth value almost satisfies the additive rule based on the blending ratio of the pigment used. The amount of the pigment used is 30 to 90% by weight of the halogenated metal phthalocyanine green pigment, 0 to 60% by weight of the azo yellow pigment and / or quinophthalone yellow pigment, preferably 5 to 5%, based on the total weight of the pigment. 60% by weight is preferable from the viewpoint of the hue, brightness, and film thickness of the pixel. More preferably, 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, 58, and azo yellow pigments include C.I. I. Pigment Yellow 150 and quinophthalone yellow pigment 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 also 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 Rth close to 0 from negative. The amount used is 40 to 100% by weight of the metal phthalocyanine blue pigment and 0 to 50% by weight, preferably 1 to 50% by weight of the dioxazine violet pigment based on the total weight of the pigment. It is preferable from the viewpoints of hue, brightness, film thickness, and the like, and more preferably 50 to 98% by weight of the metal phthalocyanine blue pigment and 2 to 25% by weight of the dioxazine violet pigment.

  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 (III)], cadmium red, ultramarine, bitumen, chromium oxide green, cobalt green, and other metal oxide powders, metal sulfide powders, and metal powders. Etc.

  Inorganic pigments are used in combination with organic pigments in order to ensure good coatability, sensitivity, developability and the like while maintaining a balance between saturation and lightness. Furthermore, for color matching, a dye can be contained within a range that does not lower the heat resistance.

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

  The average primary particle diameter of the pigment is preferably 40 nm or less, more preferably 30 nm or less, and still more preferably 20 nm or less. Moreover, it is preferable that an average primary particle diameter is 5 nm or more. When the average primary particle diameter of the pigment is larger than the upper limit value, the visibility of the liquid crystal display device during black display is poor. Moreover, when smaller than a lower limit, pigment dispersion | distribution becomes difficult, it becomes difficult to maintain stability as a coloring composition and to ensure fluidity | liquidity.

  As a result, the luminance and color characteristics of the color filter are deteriorated. In particular, an organic pigment having an average primary particle diameter exceeding 40 μm adversely affects front visibility.

  In addition, each color pixel formed on the transparent substrate is sandwiched between two polarizing plates, a backlight is applied from one polarizing plate side, and the light transmitted through the other polarizing plate is measured with a luminance meter. The contrast C calculated from the ratio of the light luminance (Lp) in the parallel state and the light luminance (Lc) in the orthogonal state is calculated from C = Lp / Lc, CS is only the substrate without colored pixels, and CR is When red pixel, CY represents yellow pixel, CG represents green pixel, and CB represents blue pixel contrast, CR / CS> 0.45, CY / CS> 0.45, and CG / CS> 0.45, and When CB / CS> 0.45 is satisfied, the front visibility during black display of the liquid crystal display device is excellent as shown in Table 6. That is, it is possible to reproduce a tight black display with little light leakage.

  When CR / CS> 0.45, CY / CS> 0.45, CG / CS> 0.45, and CB / CS> 0.45 are not satisfied, that is, CR / CS ≦ 0. 45, or CY / CS> 0.45, or CG / CS ≦ 0.45, or CB / CS ≦ 0.45, light leakage during black display increases, and excellent front view Liquid crystal display device cannot be obtained.

CR / CS> 0.45, CY / CS> 0.45, and CG / CS> 0.4
5 and satisfying CB / CS> 0.45, if the retardation difference for each color is large, oblique visibility may be insufficient.

  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 during synthesis (referred to as a synthetic precipitation method) ) Etc. Depending on the synthesis method and chemical properties of the pigment to be used, an appropriate method can be selected for each pigment.

  Each method will be described below, but any method 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 according to the embodiment 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. Further, the water-soluble organic solvent is added so that the pigment and the inorganic salt are uniformly solidified, and usually 0.5% with respect to 1 part by weight of the pigment, although depending on the blending ratio of the pigment and the inorganic salt. Used in an amount of ˜30 parts by weight.

  More specifically, regarding the 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 to achieve high speed. Stir with a mixer or the like to form 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, the precipitation The primary particle size and particle shape can be controlled by the speed or the like.

  In general, pigments are difficult to dissolve in solvents, so the solvents that can be used are limited. For example, strongly acidic solvents such as concentrated sulfuric acid, polyphosphoric acid and chlorosulfonic acid, or basic substances such as dimethylformamide solution of liquid ammonia and sodium methylate Solvents are known.

  As a typical example of the precipitation method, there 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 concentration of sulfuric acid to be used 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 poor. On the other hand, if the amount is too large, the processing efficiency of the pigment decreases. Is preferably used.

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. When the injection is started at a temperature higher than this temperature, boiling occurs due to 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 vat dyes such as flavantron, perinone, perylene, and indanthrone are reduced with alkaline hydrosulfite, the quinone group becomes a hydroquinone sodium salt (leuco compound) and becomes water-soluble. A pigment having a small primary particle size insoluble in water can be precipitated by adding an appropriate oxidizing agent to the aqueous solution for oxidation.

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

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

  In addition, a retardation adjusting agent can be added to the color filter coloring composition of one or more colors in the color filter according to the present embodiment, particularly for the purpose of improving oblique visibility. A retardation adjusting agent is an additive that can adjust 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 that can be used as a retardation adjusting agent is preferably an organic compound with good dispersibility in order to ensure a high contrast of 1000 or 3000 or more. In addition, particles having an inorganic shape such as inorganic substances can be used, but it is desirable to avoid them from the viewpoint of light scattering and depolarization. In addition, when a color filter of a plurality of colors is formed on a transparent substrate or the like, a retardation adjusting agent may be added to all colors, but it is also possible to add only one color, two colors, or three colors. is there.

Specific retardation adjusting agents are selected from organic compounds having a planar structure group having one or more crosslinkable groups, melamine resins, porphyrin compounds, benzylic compounds, styrenic compounds, and polymerizable liquid crystal compounds. More than seeds can be selected.

As a result of intensive studies so far, the present inventors have invented that retardation can be adjusted with a melamine resin, a benzyl compound, and a styrene compound.
Japanese Patent Application No. 2007-021897
Japanese Patent Application No. 2007-021898
Japanese Patent Application No. 2007-021899 (Melamine)
Japanese Patent Application No. 2008-322529
Japanese Patent Application No. 2009-545745
Japanese Patent Application No. 2008-322529
Japanese Patent Application No. 2008-322530 (Styrene resin OOC joint application)
Japanese Patent Application No. 2009-118643 (benzyl type)

  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, For polycyclic hydrocarbons such as cinnamyl and trityl groups, pentarenyl, indenyl, naphthyl, biphenylene, acenaphthylene, fluorene, phenanthryl, anthracene, triphenylene, pyrene, naphthacene, pentaphen, pentacene A known compound having a group, a tetraphenylene group, a trinaphthylene group, or the like can be used. For heteromonocyclic compounds, pyrrolyl group, imidazolyl group, pyrazolyl group, pyridyl group, pyrazinyl group, triazine group, etc.For heteropolycyclic compounds, indolizinyl group, isoindolyl group, indolyl group, purinyl group, quinolyl group, isoquinolyl group, phthalazinyl Group, naphthyridinyl group, quinoxalinyl group, cinolinyl group, carbazolyl group, carbolinyl group, acridinyl group, porphyrin group, and the like, which are exemplified by those having substituents such as hydrocarbon groups and halogen groups. May be.

  The at least one crosslinkable group attached to the planar structure group includes an unsaturated polymerizable group (A, B, C, D, E, F) represented by the following formula (I) or a functional group (I , J, K, L, M, N, O) or a thermally polymerizable group (G, H, P, Q, R, S, T, U), and an epoxy group (G, H) is more preferable. P to 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 ) ₇ CH ₃ , —OCO (C ₆ H ₄ ) O (CH ₂ ) ₆ CH═CH _{2 and the} like are also preferably used.

  These crosslinkable groups 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 (II) can be preferably used, but any compound having the above-described planar structural group may be used. Examples of melamine compounds are given below.

In the formula, R ₁ , R ₂ and R ₃ are a hydrogen atom, methylol group, alkoxymethyl group, alkoxy n-butyl group, R ₄ , R ₅ and R ₆ are methylol group, alkoxymethyl group and alkoxy n-butyl, respectively. It is a group. 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, compounds represented by the following general formula (III) are also preferably used.

R _{7 to} R ₁₄ 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. n is an integer of 1 to 20, and 2 is preferably used.

  Alternatively, a compound having a porphyrin skeleton represented by the following general formula (IV) can be preferably used.

In the formula, R _{15 to} R ₂₂ are each independently a hydrogen atom, a halogen atom, an alkoxy group, an alkylthio group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted naphthoxy group, a substituted or unsubstituted phenylthio group, or a substituted group Alternatively, it represents an unsubstituted naphthylthio group. Examples of the halogen atom for R _{15 to} R ₂₂ include fluorine, chlorine, bromine and iodine. The alkoxy group and 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 a linear chain having 1 to 8 carbon atoms. Particularly preferred are branched or cyclic alkyl groups. -Z represents -CH- or -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 a phenoxy group, 2-methylphenoxy group, 3-methylphenoxy group, 4-methylphenoxy group, 2-ethylphenoxy group, reference number: P20080487, Japanese Patent Application No. 2008-. 175606 Date of submission: July 4, 2008 163-ethylphenoxy group, 4-ethylphenoxy group, 2,4-dimethylphenoxy group, 3,4-dimethylphenoxy group, 4-t-butylphenoxy group, 4-amino A phenoxy group, 4-dimethylaminophenoxy group, 4-diethylaminophenoxy group, etc. are mentioned.

  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 planar 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 novolac type epoxy compounds , Novolak type epoxy compounds such as cresol novolac type epoxy compounds; for example, glycidyl amine type epoxy compounds such as tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, tetraglycidyl-m-xylenediamine; For example, diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, etc. 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 the following general formula (V).

  As the polymerizable liquid crystal compound, rod-like liquid crystal molecules or discotic liquid crystal molecules can be applied, and in particular, discotic liquid crystal molecules are preferable. As the rod-like liquid crystalline molecules, liquid crystalline molecules described in JP-A-2006-16599 can be employed. For example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid Phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are also used. As the discotic liquid crystalline molecules, for example, those described in JP-A-8-27284 can be used. Examples thereof are shown in the following general formula (VI).

  In the above formula, Y represents a divalent linking group selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof; 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), a functional group (I, J, K, L, M, N, O) in the above-described formulas (A) to (U). ) And a thermally polymerizable group (G, H, P, Q, R, S, T, U), or an alkyl group, an alkenyl group substituted with the crosslinkable group, An aryl group or a heterocyclic group.

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 (C ₆ H ₄ ) O (CH ₂ ) ₆ CH═CH _{2 and the} like are also preferably used.

  Below, the coloring composition used in order to form each color pixel of the color filter which concerns on this embodiment is demonstrated.

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

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

  The pigment carrier can be used in an amount of 30 to 700 parts by weight, preferably 60 to 450 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  When a mixture of a transparent resin and its precursor is used as a pigment carrier, the transparent resin is 20 to 400 parts by weight, preferably 50 to 250 parts by weight, based on 100 parts by weight of the pigment in the coloring composition. Can be used.

  The precursor of the transparent resin can be used in an amount of 10 to 300 parts by weight, preferably 10 to 200 parts by weight, with respect to 100 parts by weight of the pigment in the coloring composition.

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

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

  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, acrylonitrile and the like. These can be used alone or in admixture of two or more.

  When the composition is cured by ultraviolet irradiation, a photopolymerization initiator or the like is added to the 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 Til) -6-styryl-s-triazine, 2- (naphth-1-yl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4-methoxy-naphth-1-yl) -4 , 6-Bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl (4′-methoxystyryl) -6-triazine, etc. A polymerization initiator, a borate photopolymerization initiator, a carbazole photopolymerization initiator, an imidazole photopolymerization initiator, or the like is used.

  A photoinitiator can be used in the amount of 5-200 weight part with respect to 100 weight part of pigments in a coloring composition, Preferably it is 10-150 weight part.

  The above photopolymerization initiators are used alone or in combination of two or more. As sensitizers, α-acyloxy ester, acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone. , Camphorquinone, ethylanthraquinone, 4,4′-diethylisophthalophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 4,4′-diethylaminobenzophenone, etc. It can also be used together.

  The sensitizer can be contained in an amount of 0.1 to 60 parts by weight with respect to 100 parts by weight of the photopolymerization initiator.

  Furthermore, the coloring composition can contain a polyfunctional thiol that functions as a chain transfer agent. The polyfunctional thiol may be a compound having two or more thiol groups. For example, hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene Glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhioglycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris (3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, Pentaerythritol tetrakisthiopropionate, trimercaptopropionic acid tris (2-hydroxyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercap -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 , Methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvent, and the like. These may be used alone or in combination.

  The solvent can be used in an amount of 800 to 4000 parts by weight, preferably 1000 to 2500 parts by weight with respect to 100 parts by weight of the pigment in the coloring composition.

  The coloring composition comprises one or more pigments, if necessary, together with the above photopolymerization initiator, in a pigment carrier and an organic solvent, such as a three roll mill, a two roll mill, a sand mill, a kneader, and an attritor. It can be manufactured using dispersion means.

  Moreover, the coloring composition containing 2 or more types of pigments can also be manufactured by mixing each pigment separately finely dispersed in a pigment carrier and an organic solvent.

  When the pigment is dispersed in the pigment carrier and the organic solvent, a dispersion aid such as a resin-type pigment dispersant, a surfactant, or a pigment derivative can be appropriately contained.

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

  The resin-type pigment dispersant has a pigment-affinity part that has the property of adsorbing to the pigment and a part that is compatible with the pigment carrier, and adsorbs to the pigment to stabilize the dispersion of the pigment on the pigment carrier. It works.

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

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

  The dye derivative is a compound in which a substituent is introduced into an organic dye, and is preferably close to the hue of the pigment to be used. However, if the addition amount is small, those having different hues may be used.

  Organic dyes also include light yellow aromatic polycyclic compounds such as naphthalene and anthraquinone that are not generally called dyes.

Examples of the dye derivatives are described in JP-A-63-305173, JP-B-57-15620, JP-B-59-40172, JP-B-63-17102, JP-B-5-9469, and the like. You can use what you have. In particular, a pigment derivative having a basic group is preferably used because it has a large pigment dispersion effect. These can be used alone or in admixture of two or more.

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

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

  The coloring composition can be prepared in the form of gravure offset printing ink, waterless offset printing ink, inkjet ink, silk screen printing ink, solvent development type or alkali development type color resist. The colored resist is obtained by dispersing a dye in a composition containing a thermoplastic resin, a thermosetting resin or a photosensitive resin, a monomer, a photopolymerization initiator, and an organic solvent.

  The pigment is preferably contained in a proportion of 5 to 70% by weight based on the total solid content of the colored composition (100% by weight). More preferably, it is contained in a proportion of 20 to 50% by weight, and the remainder consists essentially of a resinous binder provided by a pigment carrier.

  The colored composition is removed by means of centrifugal separation, sintering filter, membrane filter, etc. to remove coarse particles of 5 μm or more, preferably coarse particles of 1 μm or more, more preferably 0.5 μm or more and coarse particles It is preferable to carry out.

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

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

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

  The ink jet method is a method in which an ink jet apparatus in which a plurality of fine discharge ports (ink jet heads) are arranged 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. If necessary, the dried film is exposed to ultraviolet light through a mask having a predetermined pattern provided in contact with or non-contact with the film.

  Then, after immersing in a solvent or alkali developer or spraying the developer by spraying or the like to remove the uncured portion to form a desired pattern, the same operation is repeated for other colors to produce a color filter. be able to.

  Furthermore, in order to accelerate the polymerization of the colored resist, heating can be performed as necessary.

  According to the photolithography method, a color filter with higher accuracy than the above printing method can be manufactured.

  In development, an aqueous solution such as sodium carbonate or sodium hydroxide is used as an alkali developer, and an organic alkali such as dimethylbenzylamine or triethanolamine can also be used. Moreover, an antifoamer and surfactant can also be added to a developing solution. As a development processing method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid accumulation) development method, or the like can be applied.

  In order to increase the UV exposure sensitivity, after coating and drying the colored resist, a water-soluble or alkaline water-soluble resin such as polyvinyl alcohol or a water-soluble acrylic resin is applied and dried to form a film that prevents polymerization inhibition by oxygen. Thereafter, ultraviolet exposure can also be performed.

  The color filter suitably used for 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 of manufacturing a color filter by electrodepositing each color filter segment on a transparent conductive film by electrophoresis of colloidal particles using a transparent conductive film formed on a transparent substrate. 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 including the color filter according to one embodiment of the present invention described above will be described.

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

  The liquid crystal (LC) is TN (Twisted Nematic), STN (Super Twisted Nematic), IPS (In-Plane Switching), VA (Vertical Alignment), OCB (Optically Compensated B). .

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

  On the other hand, the color filter 11 of the present invention is formed on the inner surface of the second transparent substrate 6.

  The red, yellow, green and blue filter segments constituting the color filter 11 are separated by a black matrix (not shown).

  A transparent protective film (not shown) is formed so as to cover the color filter 11, and further, a transparent electrode layer 12 made of, for example, ITO is formed on the color filter 11, and the alignment layer 13 covers the transparent electrode layer 12. Is provided. A polarizing plate 14 is formed on the outer surface of the transparent substrate 6. A backlight unit 16 including a three-wavelength lamp 15 is provided below the polarizing plate 10.

  As described above, according to the present embodiment, in order to obtain a color filter with higher contrast, the thickness direction of the green pixel layer constituting the color filter is specified by specifying the pigment type to be used or by miniaturizing the pigment. Even if the phase difference value may be negative, select a pigment that can be a positive thickness direction phase difference, perform a refinement process that becomes positive, and further increase the positive thickness direction phase difference. By adding fine particles that can be adjusted, it is possible to provide a coloring composition for a color filter that can be adjusted to an optimal value so that the thickness direction retardation value is a positive value and satisfies Equation (3). Become.

  Furthermore, according to another embodiment of the present invention, a liquid crystal display is formed using the color filter according to this embodiment so as to be suitable for the optical characteristics of the optical compensation layer and other components, particularly the wavelength dispersion characteristics of retardation. When manufactured, since there is no variation in the polarization state of the light passing through the display area of each colored pixel, a liquid crystal display device excellent in viewing angle display from an oblique direction can be obtained.

  Furthermore, since the display is black with the viewing angle compensated from the oblique direction, when viewed from the oblique direction, the color shift can be reduced, and neutral black can be reproduced, exhibiting excellent display characteristics. Can do.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, since materials used in this embodiment are extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light, and it goes without saying that all operations are performed under a yellow or red light. Yes. 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”.

  The dye derivatives used in the following examples are shown in Table 1 below.

a) Production of refined pigments The refined pigments used in Examples and Comparative Examples were produced by the following [Production Example 1] to [Production Example 7]. And the average primary particle diameter of the obtained pigment was measured by the general method which measures the magnitude | size of a primary particle directly from an electron micrograph.

  Specifically, the particles in the field of view are photographed with a transmission electron microscope JEM-2010 (manufactured by JEOL Ltd.), and the minor axis diameters of the primary particles of the individual pigments constituting the aggregate on the two-dimensional image The major axis diameter was measured, and the average was taken as the particle diameter of the pigment particles.

  Next, for 100 or more pigment particles, the volume (weight) of each particle was obtained by approximating the obtained particle size to a rectangular parallelepiped, and the volume average particle size was defined as the average primary particle size. At this time, the colored composition as a sample was ultrasonically dispersed in a solvent, and then the particles were photographed with the microscope. The same result can be obtained by using either a transmission type (TEM) or a scanning type (SEM). 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.

[Production Example 1]
A sulfonation flask was charged with 170 parts of tert-amyl alcohol under a nitrogen atmosphere. Then 11.04 parts of sodium were added and the mixture was heated to 92-102 ° C. The molten sodium was then held overnight at 100-107 ° C. 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 was stirred at 80 ° C. for a further 3 hours and at the same time 4.88 parts of diisopropyl succinate were added dropwise.

  The reaction mixture was 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 was continued at 20 ° C. for 6 hours. The red mixture was filtered, and the residue was washed with methanol and water, and then dried at 80 ° C. to obtain 46.7 parts of a diketopyrrolopyrrole red pigment (R-1).

[Production Example 2]
Diketopyrrolopyrrole red pigment PR254 (“Irgafore Red B-CF” manufactured by Ciba Specialty Chemicals; 100 parts of (R-2), 18 parts of pigment derivative (D-1), 1000 parts of crushed salt, and diethylene glycol 120 The parts were placed in a stainless gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 60 ° C. for 10 hours.

  The mixture was poured into 2000 parts of warm water and stirred for about 1 hour with a high-speed mixer while heating to about 80 ° C. 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 a salt milled pigment (R-3). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 3]
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 Manufacturing Co., Ltd.) 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-4). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 4]
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.

  Next, after adding 25.6 parts of barbituric acid, it heated up to 55 degreeC and stirred as it was for 2 hours. Next, 25.6 parts of barbituric acid was added, the temperature was raised to 80 ° C., and then 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 dropping, complexation was performed at 90 ° C. for 1.5 hours.

  Thereafter, the pH was adjusted to 5.5, and 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 for 4 hours. Stir. After cooling to 70 ° C., it was quickly filtered, and washing with warm water at 70 ° C. was repeated until the inorganic salt could be washed.

  Thereafter, 14 parts of an azo yellow pigment (Y-1) was obtained through drying and grinding processes. The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 5]
160 parts of yellow pigment (CI Pigment Yellow 138, "PALIOTOL YELLOW K0961HD" manufactured by BASF), 1600 parts of sodium chloride, and 270 parts of diethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) are made of stainless steel 1 gallon kneader (manufactured by Inoue Seisakusho). And kneaded at 60 ° C. for 15 hours. Next, this mixture is poured into about 5 liters of warm water, heated to about 70 ° C. and stirred with a high speed mixer for about 1 hour to form a slurry, then filtered and washed to remove sodium chloride and diethylene glycol, After drying at 80 ° C. for 24 hours, 157 parts of a salt milled pigment (Y-2) was obtained.

[Production Example 6]
120 parts of halogenated copper phthalocyanine-based green pigment PG36 (“Rionol Green 6YK” manufactured by Toyo Ink Manufacturing Co., Ltd.), 1600 parts of crushed sodium chloride, 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).

  The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 7]
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). The primary particle diameter of the obtained pigment is shown in Table 2 below.

[Production Example 8]
100 parts of copper phthalocyanine 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 stainless steel 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). The primary particle diameter of the obtained pigment is shown in Table 2 below.

b) Preparation of Acrylic Resin Solution Put 800 parts of cyclohexanone in a reaction vessel, heat to 100 ° C. while injecting nitrogen gas into the vessel, and drop the mixture of monomers and thermal polymerization initiator below at the same temperature over 1 hour. Then, a polymerization reaction was performed.

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 After stirring and mixing a mixture having the composition (weight ratio) shown in Table 3 below, zirconia beads having a diameter of 1 mm were dispersed in a sand mill for 5 hours, and then filtered through a 5 μm filter. Thus, each color pigment dispersion was obtained.

d) Retardation adjuster A melamine compound (trade name: Nicalac MX-750; manufactured by Nippon Carbide Industries) was used as a retardation adjuster.

e) Preparation of colored composition (hereinafter referred to as resist) A mixture of compositions (weight ratio) shown in Table 4 below was uniformly stirred and mixed, and then filtered through a 1 μm filter to obtain each color resist.

f) Preparation of each color coating film Each color resist shown in Table 4 was applied to a glass substrate by spin coating, and then pre-baked at 70 ° C. for 20 minutes in a clean oven. Next, the substrate was cooled to room temperature and then exposed to ultraviolet rays using an ultrahigh pressure mercury lamp.

  Next, this substrate was spray-developed using an aqueous sodium carbonate solution at 23 ° C., then washed with ion-exchanged water and air-dried. Thereafter, post-baking was performed at 230 ° C. for 30 minutes in a clean oven to obtain each color coating film. The film thickness of the dried coating film was 2.0 μm in all cases.

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 is a spectrophotometer (manufactured by Olympus). “OSP-200”).

  Table 5 below shows the chromaticity of each color coating film prepared from each color resist shown in Table 4 above.

[Thickness direction retardation value Rth]
The thickness direction retardation value can be obtained as follows. Using a transmission spectroscopic ellipsometer (“M-220” manufactured by JASCO Corporation), measurement is performed at a wavelength of 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. Then, the ellipso parameter δ was obtained.

  The retardation value Δ (λ) at each wavelength can be obtained from Δ = δ / 360 × λ, and the three-dimensional refractive index is calculated using this value, and the thickness direction retardation value (Rth) is calculated from the following equation 4. Asked.

  Although Rth of each wavelength can be obtained from the above measurement, in this evaluation, the red pixel was calculated as 610 nm, the yellow pixel as 580 nm, the green pixel as 545 nm, and the blue pixel as 450 nm.

Rth = {(Nx + Ny) / 2−Nz} × d (4)
In the formula, Nx is a refractive index in the x direction in the plane of the colored pixel layer, Ny is a refractive index in the y direction in the plane of the colored pixel layer, and Nz is a refractive index in the thickness direction of the colored pixel layer. , Nx is a slow axis where Nx ≧ Ny. d is the thickness (nm) of the colored pixel layer.

  The thickness direction retardation value Rth of each color coating film produced from each color resist shown in Table 4 is shown in Table 5 below.

[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).

  Further, contrast of only the substrate without colored pixels = Lp / Lc is CS, CR is a red pixel, CY is a yellow pixel, CG is a green pixel, and CB is a blue pixel.

  The luminance was measured using a color luminance meter (“BM-5A” manufactured by Topcon Corporation) under the condition of a 2 ° visual field, and “NPF-SEG1224DU” manufactured by Nitto Denko Corporation was used as the polarizing plate.

h) Production of color filter A color filter was produced by the method shown below by combining the color resists shown in Table 4 above.

[Example 1]
First, the red resist (R1) 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, the substrate was cooled to room temperature, and then exposed to ultraviolet rays 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, using yellow resist (Y1), green pixels are formed in the same manner, further using green resist (G1), forming green pixels in the same manner, and further using blue resist (B1). Similarly, blue pixels were formed to obtain a color filter. The film thickness of each color pixel was 2.0 μm.

i) Production of liquid crystal display device An overcoat layer was formed on the obtained color filter, and a polyimide alignment layer was formed thereon. And the polarizing plate was formed in the other surface of this glass substrate.

  On the other hand, a TFT array and a pixel electrode were formed on one surface of another (second) glass substrate, and a polarizing plate was formed on the other surface.

  The two glass substrates prepared in this manner face each other so that the electrode layers face each other, and are aligned while using a spacer bead to keep the distance between the two substrates constant, leaving a liquid crystal composition injection opening. The periphery was sealed with a sealant. Next, a liquid crystal composition for VA was injected from the opening, and the opening was sealed. Furthermore, an optical compensation layer optimized so that a wide viewing angle display is possible is provided on the polarizing plate.

  The liquid crystal display device thus fabricated was combined with a backlight unit to obtain a VA display mode liquid crystal panel.

[Example 2]
Except for changing the red resist from (R1) to (R2), the yellow resist (Y1) to (Y2), the green resist from (G1) to (G2), and the blue resist from (B1) to (B2), A liquid crystal display device was obtained in the same manner as in Example 1.

[Example 3]
The red resist is changed from (R1) to (R3), the yellow resist (Y1) to (Y3), the green resist is changed from (G1) to (G3), and the blue resist is changed from (B1) to (B3). A liquid crystal display device was obtained in the same manner as in Example 1.

[Example 4]
The red resist is changed from (R1) to (R4), the yellow resist (Y1) to (Y4), the green resist is changed from (G1) to (G4), and the blue resist is changed from (B1) to (B4). A liquid crystal display device was obtained in the same manner as in Example 1.

[Comparative Example 1]
A liquid crystal display device was prepared in the same manner as in Example 1 except that the yellow resists (Y1) to (Y4), the green resists (G1) to (G4), and the blue resists (B1) to (B2) were changed. Obtained.

[Comparative 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 (R1) to (R4), the green resist was changed from (G1) to (G3), and the blue resist was changed from (B1) to (B2). Got.

[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 (R1) to (R3), the yellow resist (Y1) to (Y2), and the green resist was changed from (G1) to (G2). Got.

j) Visibility evaluation during black display of the liquid crystal display device The produced liquid crystal display device is displayed in black and leaks from the normal direction (substantially vertical direction) 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. Also, the chromaticity (u (、), v (⊥)) when viewed from a substantially vertical direction when displaying black and the chromaticity when viewed from an orientation inclined up to 60 ° from the normal direction of the display surface ( u (45), v (45)) were measured with Topcon BM-5A, the color difference Δu′v ′ was calculated, and the maximum value of Δu′v ′ at 0 ≦ θ ≦ 60 ° was determined. The evaluation rank is as follows, and the results are shown in Table 5 below.

<Comparison result>
In each of Examples 1 to 4 according to the present invention, the thickness direction retardation values of the red pixel, the green pixel, and the blue pixel layer of the color filter satisfy the above formulas (1) and (2). Since the formed color filter is used in a liquid crystal display device, the chromaticity difference between the normal direction and the diagonal direction of the display surface satisfies the above-described formula (3), and the front and diagonal directions are formed. A liquid crystal display device having good visibility was obtained. On the other hand, the comparative products according to Comparative Examples 1 and 2 are formed such that the thickness direction retardation values of the red pixel, yellow pixel, green pixel, and blue pixel layers satisfy both the above-described formulas (1) and (2). Since the phase difference in the thickness direction of the red pixel, the yellow pixel, the green pixel, and the blue pixel is not good, color shift occurs in the oblique direction, resulting in poor visibility.

  DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Black matrix, 3 ... Colored pixel, 3 (R) ... Red pixel, 3 (Y) ... Yellow pixel, 3 (G) ... Green pixel 3 (B) ... blue pixels, 4 ... liquid crystal display device, 5,6 ... transparent substrate, 7 ... TFT array, 8,12 ... transparent electrode, 9,13 ... Alignment layer 10, 14, ... Polarizing plate, 11 ... Color filter, 15 ... Three-wavelength lamp, 16 ... Backlight unit.

Claims (5)

At least a red pixel, a yellow pixel, a green pixel, and a blue pixel are provided. The red pixel has a thickness direction retardation value Rth (R), a yellow pixel thickness direction retardation value Rth (Y), and a green pixel thickness direction. A color filter for a liquid crystal display device, wherein the retardation value Rth (G) and the thickness direction retardation value Rth (B) of the blue pixel satisfy the following expression (1) or expression (2).
Rth (R) <Rth (Y) <Rth (G) <Rth (B) (1)
Rth (B) <Rth (G) <Rth (Y) <Rth (R) (2)
(Where Rth (R), Rth (Y), Rth (G), and Rth (B) are values obtained by subtracting the refractive index in the thickness direction from the average in-plane refractive index of each pixel, and the thickness of the pixel. Rth (R) is a thickness direction retardation value for light having a wavelength of 610 nm passing through the red region, and Rth (Y) is a thickness direction retardation value for light having a wavelength of 580 nm passing through the yellow region. Rth (G) represents a thickness direction retardation value for light having a wavelength of 545 nm passing through the green region, and Rth (B) represents a thickness direction retardation value for light having a wavelength of 450 nm passing through the blue region.   2. The color filter for a liquid crystal display device according to claim 1, wherein at least one of the colored pixels is made of a photosensitive coloring composition to which a retardation adjusting agent is added. The retardation adjusting agent is an organic compound selected from one or more selected from an organic compound having a planar structural group having one or more crosslinkable groups, a melamine compound, and a benzylic compound. Item 3. The color filter according to Item 2. A liquid crystal display device comprising: a liquid crystal cell comprising the color filter according to claim 1; a polarizing plate disposed on each outer surface of the liquid crystal cell; and an optical compensation layer provided on the inner side of the polarizing plate. The liquid crystal display device is displayed in black, and the chromaticity (u, v) expressed in the CIE 1960 color system is measured, and the chromaticity (u (⊥), v (⊥)) when viewed from the vertical direction is displayed. The chromaticity difference Δuv represented by the following formula (3) of chromaticity (u (θ), v (θ)) when viewed from an orientation inclined by θ ° from the normal direction of the surface is 0 <θ ≦ A liquid crystal display device characterized by being 0.02 or less in the range of 60.
Δuv = [{u (⊥) −u (θ)} 2+ {v (⊥) −v (θ)} 2] 1/2 · (3)   The liquid crystal display device according to claim 3, wherein the liquid crystal display device is a VA method or an IPS method.

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