JP2002348493A - Red color paste, color filter and liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective or semi-transmissive reflective liquid crystal display panel that is bright and excellent in visibility, by manufacturing a color filter having a superior surface flatness which enables high transmission and color purity to be made compatible under environmental lights and then by using this color filter and utilizing environmental lights. SOLUTION: The red color paste contains at least a quinacridone pigment, a sulfonated derivative of the quinacridone pigment, and a resin component. The color filter manufactured by using this color paste and the liquid crystal display panel are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of a red color paste, a color paste for forming a red pixel of a color filter, and in particular, a color liquid crystal display panel used for displaying character information and image information. The present invention relates to a color filter, and more particularly, to a color filter used for manufacturing a reflective or transflective color liquid crystal panel used for a mobile phone, a personal digital assistant (PDA) or the like.

[0002]

2. Description of the Related Art At present, liquid crystal display panels are used in various applications such as notebook computers, desktop monitors, car navigation systems, digital cameras, etc., taking advantage of their characteristics such as light weight, thinness, and low power consumption. BACKGROUND ART In a liquid crystal display panel using a backlight, it is required to increase the use efficiency of backlight light in order to reduce power consumption, and a higher transmittance of a color filter is required. Although the transmittance of color filters is improving year by year,
Significant reduction in power consumption due to improved transmittance is no longer expected. In recent years, a reflection type liquid crystal display panel which does not require a backlight light source which consumes a large amount of power has been adopted for a mobile phone in recent years. A color filter for a reflective liquid crystal display panel cannot reproduce bright and vivid colors simply by reducing the pixel thickness of the color filter for a transmissive liquid crystal display panel. As an example of a color filter that reproduces bright and vivid red, a chromaticity range of a red pixel for a reflective liquid crystal display panel is described in Japanese Patent Application Laid-Open No. 10-339871. As a combination of pigments for obtaining a red pixel for a reflective liquid crystal display panel, Japanese Patent Application Laid-Open No. H11-100529 describes that a combination of a violet pigment PV19 and an orange pigment PO71 exhibits particularly good color characteristics. However, it was not sufficient to satisfy the brightness required for a color filter for a reflective liquid crystal display panel. Also, JP-A-2000-2498
No. 24 describes that the use of the red pigment PR209 provides color characteristics suitable for a reflective liquid crystal display panel. However, there is a problem that the dispersion state of the color paste containing PR209 is unstable, and it is difficult to increase the production yield of the color filter. In addition, pixels formed using a color paste whose dispersion state is unstable have a rough surface. If the pixel surface is rough,
When the formation of the overcoat film and the surface polishing treatment are omitted for cost reduction, the alignment state of the liquid crystal molecules may be disturbed. In particular, a transmissive liquid crystal display panel generally uses a display mode mainly utilizing the optical rotation of a liquid crystal, such as a twisted nematic (TN) mode, whereas a reflective liquid crystal display panel generally uses a liquid crystal display. Since the display mode uses birefringence, the display quality of the panel such as the contrast ratio is greatly affected by the flatness of the pixel surface.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and is directed to a red color filter for forming a red pixel of a color filter suitably used for a reflective or transflective liquid crystal display panel. Providing a paste while stabilizing the dispersed state, providing a color filter having red pixels suitable for a reflective or transflective liquid crystal display panel by using the color paste,
It is an object of the present invention to provide a reflective or transflective crystal display panel having good color characteristics using the color filter.

[0004]

In order to achieve the above object, a color paste, a color filter and a liquid crystal display panel of the present invention basically have the following constitution.

That is, a red color paste containing at least a quinacridone pigment, a sulfonated derivative of the quinacridone pigment, and a resin component, a color filter obtainable from the color paste, and a color filter obtained by using the color filter. A reflective or transflective liquid crystal display panel characterized by being manufactured.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The quinacridone pigment in the present invention is a compound represented by the general formula (1), wherein the bonding position (R _{1 to} R ₁₀ ) of the aromatic ring of quinacridone is halogen instead of hydrogen. A substituent such as a cyano group, an alkyl group or an alkoxy group may be attached. Alkyl group, the number of carbon atoms of the alkoxy group is C ₁ -C _15, preferably C ₁ -C _10, more preferably from C ₁ -C _5.

[0007]

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[0008] As shown in equation (2), PR209
It has a structure in which R ₂ and R ₇ are substituted with chlorine atoms.

[0009]

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[0010] Other examples of the quinacridone pigments include, for example, PR122 and PV19. P
R122 is as represented by the formula (3), and has a R ₃ and R ₆ is substituted with a methyl group structure.

[0011]

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As shown in the equation (4), PV19 is R
₁ to R ₁₀ has the structure as-hydrogen atom.

[0013]

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In order to form a red pixel having good heat resistance and light resistance, it is effective to use a quinacridone red pigment, particularly PR209, as a coloring agent.

The sulfonated derivative of the quinacridone pigment in the present invention is a quinacridone in which a sulfonic acid group is introduced at the bonding position (R _{1 to} R ₁₀ ) of the aromatic ring. The number of functional groups to be introduced and the position to be introduced are not particularly limited, but are, on average, preferably more than 2 (more preferably 2.1 or more, further preferably 2.2 or more). . If the value is below the above range, the effect of stabilizing the dispersion of the pigment may be undesirably reduced. The introduction position is not limited at all, but generally, R ₂ , R ₃ , R ₆ and R ₇ are most easily introduced, and then R ₁ , R ₄ , R ₅ and R ₈ And
R ₉ and R ₁₀ . However, when these sites are substituted with halogen or the like, the tendency of the introduction position may change. For example, in the case of PR209, R ₁ , R ₃ , R ₆ , and R _{8 at the} ortho position of the chlorine atom are most easily introduced, and then either R ₉ or R ₁₀ (both cases of R ₉ and R ₁₀ are Rare) and rarely introduced into R ₄ or R ₅ which is a meta position of a chlorine atom.

[0016] The sulfonated derivative of the quinacridone pigment may be a single kind of pure derivative having the same number of introduced or introduced positions, or a mixture of different derivatives.

In order to increase the production yield of the color filter and to flatten the pixel surface, it is necessary to stabilize the dispersion state of the quinacridone pigment such as the red pigment PR209 in the color paste for forming the pixel. In order to maintain a good dispersion state, it is effective to include a sulfonated derivative in the color paste.

The fact that the pixel surface is flat means that the surface roughness of the pixel is low. Surface roughness is Japanese Industrial Standard J
The surface roughness Ra defined by IS B0601 is preferably used. The surface roughness Ra of the pixel is preferably 20 n
m (more preferably 10 nm or less, further preferably 5 nm or less). Although there is no particular lower limit for the surface roughness, the limit is actually 0.1 nm or more. In addition,
The quinacridone pigment and the sulfonated derivative thereof preferably have the same basic skeleton except for the sulfonic acid group. For example, if the quinacridone pigment is PR209, the sulfonated derivative of the quinacridone pigment is preferably a PR209 sulfonated derivative. This is because, as much as possible, the same chemical structure has a stronger intermolecular force due to dipole interaction and the like, and the sulfonated derivative is more likely to be adsorbed to the pigment in the dispersion medium.

The sulfonated derivative of a quinacridone pigment such as PR209 used in the present invention is synthesized, for example, by the following method. Quinacridone pigments in concentrated sulfuric acid,
The mixture is charged into fuming sulfuric acid, chlorosulfonic acid, or a mixture thereof to perform a sulfonation reaction. The reaction solution is preferably diluted with a large amount of water or neutralized with a metal alkali aqueous solution or amine aqueous solution. The obtained suspension is filtered, washed with an aqueous washing solution, and dried.

When sulfonation is carried out by the above method, the amount of sulfonic acid groups introduced per molecule can be controlled by adjusting the reaction solution concentration, reaction temperature, reaction time, and the like. The dispersion stabilizing effect tends to increase as the amount of sulfonic acid groups introduced per molecule increases, and it is preferable that the amount of sulfonic acid groups introduced averages more than two per molecule.

When neutralization is performed in the above synthesis process,
It is preferable to use an amine aqueous solution rather than to use a metal alkali aqueous solution since there is less concern that the alkali metal remains in the pixels of the color filter and adversely affects the electrical characteristics of the liquid crystal. That is, in the present invention, the sulfonic acid is preferably used in the form of a neutralized amine salt as described above. As the amine aqueous solution, an aqueous solution of ammonia, monoethanolamine, tetramethylammonium hydroxide or the like can be used,
In the present invention, various amine aqueous solutions can be used without particular limitation. However, use of ammonia is most preferable from the viewpoint of production cost.

The sulfonated derivative of the present invention may have a functional group such as an amide group introduced into a sulfonic acid group or the like, if necessary, in order to further improve the dispersibility of the pigment. For example, it is preferable to use one obtained by converting a sulfonic acid group into a sulfonamide group as in the following formula.

—SO ₂ —NH— (CH ₂ ) _m —NR′R ″ (m = 2,3, R ′ and R ″ are a methyl group and / or an ethyl group) In the present invention, PR209 and In the case of the sulfonated derivative of PR209, the weight ratio is usually 50:50 to 99.5:
0.5, preferably 60:40 to 99: 1, more preferably 70:30 to 98: 2, even more preferably 80: 2.
It is mixed at a ratio of 0 to 97: 3. The same applies to other quinacridone pigments. If the amount of the sulfonated derivative is too small, the effect of stabilizing the pigment dispersion is not exhibited. Conversely, if the amount of the sulfonated derivative is too large, the color tone of the pixel may change undesirably, and there is also a problem in terms of manufacturing cost. Becomes

In the present invention, it is preferable to use a pigment other than quinacridone as a pigment component constituting the red pixel in order to obtain a desired color tone of the red pixel. Taking PR209 as an example of a quinacridone-based pigment as an example, pigments that can be suitably used by mixing with PR209 include red pigments PR202, PR206, PR207,
PR242, PR254, purple pigment PV38, orange pigment PO38 and the like. When PR209 and a pigment other than PR209 are combined, PR209 and PR209 are used.
Other pigments are usually mixed in a weight ratio of 50:50 to 95: 5, preferably 60:40 to 90:10.

For the pigments other than the above-mentioned quinacridone pigments, the embodiments such as sulfonation, neutralization or amidation thereof, which are described in detail for the quinacridone pigments, are similarly effective.

It is also effective to combine a plurality of quinacridone pigments. For example, it is preferred to combine PR122 and PR19 with PR209, usually at a weight ratio of 50:50 to 95: 5, preferably 6
It is mixed in the range of 0:40 to 90:10. PR209
If the amount of other pigments is too large or too small, desired color characteristics may not be obtained. The same applies to quinacridone pigments other than PR209.

In the color paste of the present invention, it is desirable that the resin component for forming pixels is alkali-soluble during pattern processing. When the resin component is alkali-soluble, patterning of the colored film (that is, pixels) can be performed with an aqueous developer, and there is no problem of flammability, which is preferable for disaster prevention. As the alkali-soluble resin component, a polymer containing a carboxyl group is usually used.

In the color paste and the color filter of the present invention, a photosensitive or non-photosensitive resin at the time of pattern processing can be used as a resin component.
When a photosensitive resin is used, there is an advantage that the manufacturing process of the color filter can be shortened. On the other hand, when a non-photosensitive resin is used, a situation in which a photopolymerization initiator, a sensitizer, a decomposition product thereof, and the like remain in the formed pixel component, which adversely affects the electrical characteristics of the liquid crystal. There is an advantage that there is no fear of inviting.

In the present invention, as the photosensitive resin, a resin composed of a photopolymerizable polymer such as an acrylic resin or an epoxy resin, a monomer or an oligomer can be used alone or in combination. Photosensitive color pastes are usually prepared by adding a quinacridone pigment or a sulfonated derivative thereof, optionally a red or purple pigment other than the quinacridone pigment or an orange pigment, water or an organic solvent, a photopolymerization initiator and / or It is prepared by mixing a sensitizer.

In the present invention, as the non-photosensitive resin, an imide-based, amide-based, or epoxy-based resin can be used alone or as a mixture. A non-photosensitive color paste is usually prepared by mixing these resins with a quinacridone pigment or a sulfonated derivative thereof, and in some cases, a red pigment, a purple pigment or an orange pigment other than the quinacridone pigment, water, or an organic solvent.

When the sulfonated derivative is an acid or a salt, it is desirable that the polarity of the pigment dispersing solvent be large in order to increase the effect of preventing pigment aggregation due to electrostatic repulsion. A solvent having a relative dielectric constant of 10 or more, preferably 15 or more, more preferably 20 or more, and still more preferably 25 or more is suitably used.

A surfactant, a surface conditioner, a leveling agent, an antifoaming agent and the like can be added to the photosensitive and non-photosensitive color pastes as required.

In each case, a non-alkali-soluble resin or a non-photosensitive resin may be present in the form of a mixture or copolymer as long as the alkali solubility or photosensitivity is not impaired. Even if you have
It is preferably at most 80% by weight.

The color paste is prepared by directly dispersing the pigment in the resin solution using a disperser, or dispersing the pigment in water or an organic solvent using a disperser to prepare a pigment dispersion.
Thereafter, it is manufactured by a method of mixing with a resin solution.
The method for dispersing the pigment is not particularly limited, but a method using a sand mill, a ball mill, a three-roll mill, an attritor, or the like is preferably employed. The quinacridone pigment and the sulfonated derivative of the quinacridone pigment can be separately dispersed and then mixed.However, in order to improve the dispersibility of the quinacridone pigment, when dispersing the quinacridone pigment, It is preferable to add a quinacridone pigment sulfonated derivative.

The pigment dispersion stability in the color paste can be evaluated by measuring the yield value. The yield value measures the viscosity of the color paste at different shear rates,
It is obtained by using the equation of sson. It is estimated that the smaller the yield value, the smaller the degree of aggregation of the pigment. The yield value of the color paste is 1 × 10 ^-2 Pa or less, preferably 1
It is desirable that the pressure be not more than × 10 ⁻³ Pa.

The red color paste of the present invention preferably refers to RGB (R: red, G: green) of a color display device (especially a liquid crystal color filter, more preferably a reflective or transflective liquid crystal display panel). , B: blue) pixels. In general, the color paste itself also exhibits a red color, but it is sufficient that the color or the color display device has a color tone appropriate for a red pixel when the color display device is completed. Therefore, in rare cases, the color paste itself may not be red, but may be changed to red by a process such as heating in the process of manufacturing the pixel or the display device.

The color filter of the present invention uses a red pixel pattern by using the red color paste and a green pixel pattern and blue color paste by using the green color paste on a transparent, reflective or transflective substrate. Thus, a blue pixel pattern is formed. As the transparent substrate, inorganic glass such as quartz glass, borosilicate glass, alumina silicate glass, soda lime glass having a silica coated surface,
Organic plastic films or sheets such as polycarbonate and polymethyl methacrylate are preferably used. As the reflective substrate, silicon or a transparent substrate on which a reflective film made of a thin film of aluminum, silver, silver / copper / palladium alloy, or the like is formed is preferably used. The reflective film can be provided with a diffusion function by forming irregularities or the like. In addition, a transflective substrate can be obtained by precisely controlling the thickness of the reflective film or by patterning the reflective film.

If a black matrix is formed on the transparent, reflective or transflective substrate before forming the pixel pattern, the contrast ratio of the liquid crystal display panel can be further increased. As the black matrix, a multilayer film of chromium or chromium / chromium oxide, an inorganic film such as titanium nitride, or a resin film in which a light-shielding agent is dispersed is used, but the present invention is not limited to these, and various black matrices are used. be able to. Further, a thin film diode (TFD) or a thin film transistor (TFT) may be formed in advance on the transparent, reflective or transflective substrate, and then a pixel pattern may be formed. By forming a pixel pattern on a TFD substrate or a TFT substrate, an aperture ratio of a liquid crystal display panel can be increased and luminance can be improved.

The formation of the pixel pattern can be performed by a printing method, an electrodeposition method, or the like, but it is most preferable to perform the pixel pattern by a photolithography method because the pattern can be easily formed with high definition. The photolithography method is a method in which a color paste is applied onto the substrate, dried to form a colored film, exposed through a mask, and then exposed or unexposed portions are removed with a developer. When the resin component in the color paste is non-photosensitive, it is necessary to form a photoresist film on the colored film after forming the colored film. The photoresist film is usually removed from the colored film after forming a pattern by development. The application of the color paste to the substrate is generally performed by a method such as a spin coating method or a slit die coating method. Although an organic solvent can be used as a developer, an alkaline aqueous solution is usually used.

On the color filter of the present invention, an overcoat film, a columnar spacer, a transparent conductive film, a liquid crystal alignment film, and the like are formed as necessary.

The color filter of the present invention and the opposing substrate are bonded together using a sealant, and after the liquid crystal is injected from the injection port provided in the seal portion, the injection port is sealed. The liquid crystal display panel of the present invention is manufactured by laminating a polarizing film or a retardation film on the outside of the substrate as necessary. The present invention provides a liquid crystal display mode in which colorization is performed using a color filter, such as TN, super twisted nematic (STN), in-plane switching (IPS), and vertical alignment (VA). , Optically Convenient Bend (OCB) and the like.

In the present invention, 480 nm to 530 n
When the average transmittance at m is 10%, the average transmittance at 430 nm to 470 nm is 30% or more, preferably 4%.
By using a color filter having a red pixel that satisfies the condition that the threshold wavelength of transmittance is 0% or more and the threshold wavelength of transmittance is 550 nm or more and 575 nm or less, bright and bright red color is realized in a reflective or transflective liquid crystal display panel. it can. Here, the threshold wavelength is a wavelength at which the transmittance is 50% when the colorant concentration and the film thickness are adjusted so that the average transmittance from 480 nm to 530 nm is 10%. The average transmittance is the average value of the transmittance in the corresponding range when the transmittance is measured at intervals of 5 nm. The color paste of the present invention can suitably satisfy the above optical characteristics.

Since the color paste of the present invention has good dispersibility of the pigment, it has excellent storage stability and can increase the production yield of the color filter. The color filter of the present invention manufactured using this color paste has a flat pixel surface. The color characteristics suitable for the reflective liquid crystal display panel and the transflective liquid crystal display panel are exhibited. The reflective liquid crystal display panel and the transflective liquid crystal display panel of the present invention manufactured using this color filter can reproduce clearer colors than before, and can be used on display screens of mobile phones and PDAs. It is preferably used.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the efficacy of the present invention is not limited by the embodiments used.

[0045]

EXAMPLES were placed in Example 1 (quinacridone pigment PR209 synthesis of sulfonated derivatives) PR209 (Clariant "Hostaperm" Red EGtransp) stirred 6g while the 15 ℃ oleum (25% SO ₃₎ in 78g . After PR209 was dissolved in fuming sulfuric acid, it was heated to 30 ° C and stirred for 3 hours.
Added on 150 g of ice. After standing for 30 minutes, the resulting suspension was filtered and the obtained product was washed with 30 ml of water. The above product was put into 200 ml of water, and neutralized with an aqueous ammonia solution (aqueous ammonia solution was added until the pH became 7). 45 g of ammonium chloride was added and the mixture was stirred at 80 ° C. for 30 minutes, and the deposited precipitate was filtered at 60 ° C. The filtered wet crystals were washed with a 2% aqueous solution of ammonium chloride, then with methanol, and then dried at 80 ° C. to obtain 9 g of an amine salt as a PR209 sulfonated derivative. The obtained PR209 sulfonated derivative was dissolved in dimethylformamide deuteride (DMF-d7),
1H-NMR measurement, 13C-NMR measurement, and two-dimensional NMR measurement were performed using a nuclear magnetic resonance (NMR) analyzer.
As a result, two types of partial structures in which a sulfonic acid group was introduced at the ortho-position to the Cl atom existing in the two ring structures of PR209, a central ring structure that was sulfonated, and a central structure that was not sulfonated. The data showing the ring structure of was obtained. From the obtained data, it was estimated that about 2.5 molar equivalents of sulfonic acid groups were introduced into PR209. (Preparation and evaluation of color paste) 6.2 g of PR209
And 0.2 g of the above-mentioned PR209 sulfonated derivative;
6 g of PO38 (Clariant “Novopalm” Red HFG) was added to 92 g of γ-butyrolactone (dielectric constant 4).
1) The mixture was poured into the flask and dispersed with a homogenizer together with 200 g of glass beads at 7000 rpm for 30 minutes. Then, the glass beads were removed by filtration, and the solid content was 8%.
Red pigment dispersion was obtained. The yield value of this dispersion was measured using a viscometer (R110 manufactured by Toki Sangyo Co., Ltd.).
It was 1 × 10 ⁻³ Pa, and the dispersion state was good.

Methacrylic acid which is an acrylic polymer /
Benzyl methacrylate copolymer (acid value 100mg-KOH /
g, weight average molecular weight 50,000) 3 g, photopolymerizable acrylic monomer dipentaerythritol hexaacrylate 3.5 g, photopolymerization initiator 2-methyl-1-
0.3 g of (4-methylthiophenyl) -2-morpholinopropan-1-one, 0.2 g of 2,4-diethylthioxanthone, a surface conditioner (BYK36 manufactured by BYK Chemie)
1) 0.01 g was dissolved in 53 g of γ-butyrolactone and 40 g of 3-methoxy-3-methyl-1-butanol (MMB, relative dielectric constant: 13) to prepare a photosensitive resin solution.

6 g of red pigment dispersion, photosensitive resin solution 12
g was mixed to obtain a red color paste. When the yield value of this color paste was measured, it was 4.2 × 10 ⁻⁴ Pa, and the dispersion state of the pigment was good. (Evaluation of red pixel film) The above-mentioned red paste was applied on a non-alkali glass substrate by a spinner so that the average transmittance of the colored film from 480 nm to 530 nm became 10%. To form a red colored film. When measured using a microspectrophotometer (MCPD-2000, manufactured by Otsuka Electronics Co., Ltd.),
The average transmittance from 30 nm to 470 nm was 41%, and the threshold wavelength of the transmittance was 560 nm. When the surface roughness of the colored film was measured using a surface roughness profile measuring device (“Surfcom” 1500A, manufactured by Tokyo Seimitsu Co., Ltd.), a small value of 4 nm was obtained, and the surface was very flat. (Preparation and evaluation of color filter) The red color paste was applied on a non-alkali glass substrate on which a semi-transmissive reflection film made of a patterned aluminum thin film was formed by a spinner, dried by heating, and then exposed to ultraviolet light through a mask. The unexposed portion was dissolved and removed with a 2% aqueous solution of tetramethylammonium hydroxide (TMAH), and the mixture was cured by heating at a higher temperature than when dried to form a red pixel pattern.

Next, a green pixel pattern was obtained in the same manner using a green color paste. Green color paste is P
G36 (“Lionol” Green 6Y manufactured by Toyo Ink Manufacturing Co., Ltd.)
KP-N) and PY138 ("Paliotol" Yellow D0960, manufactured by BASF) were charged into γ-butyrolactone at a ratio of 75:25 into 2 g of a green pigment dispersion having a pigment concentration of 8% and prepared in the same manner as described above. Was prepared by mixing 18 g of the photosensitive resin solution.

Further, using a blue color paste, a blue pixel pattern was formed by the same procedure, and a color filter was manufactured. The used and blue color paste was PB15 (“Lionol” manufactured by Toyo Ink Manufacturing Co., Ltd.).
Blue 7602) was introduced into γ-butyrolactone, and 2 g of a B pigment dispersion having a pigment concentration of 8% was prepared in the same manner as described above.
And 18 g of the above-mentioned photosensitive resin solution.

The pixel film was scraped off from the glass substrate and pulverized, and dispersed in DMF-d7 to remove insoluble portions. Then, 1H-NMR measurement of the DMF-d7 solution was performed, and 13C-N
MR measurement and two-dimensional NMR measurement were performed. As a result, PR
Data was obtained indicating that some 209 had sulfonic acid groups introduced therein in an amount of about 2.5 molar equivalents. (Production and evaluation of liquid crystal display device) After forming a tin oxide-indium (ITO) film on a color filter, a polyimide alignment film was formed and rubbing treatment was performed. In addition, an ITO film was formed on a glass substrate, a polyimide alignment film was formed, and rubbing treatment was performed to obtain a counter substrate.

After the spherical spacers were scattered, the two substrates were bonded together using a sealant, and then a nematic liquid crystal ("Rixon" JC-5007LA manufactured by Chisso) was injected from an injection port provided in the seal portion. Liquid crystal injection
After leaving the empty cell under reduced pressure, the injection port was immersed in a liquid crystal tank and returned to normal pressure. After injecting the liquid crystal, the inlet was sealed with an ultraviolet curable resin to produce a liquid crystal cell. A forward scattering film, a retardation film and a polarizing film were adhered to the viewer side of the liquid crystal cell to produce a transflective liquid crystal display panel. This panel was able to reproduce bright and vivid red using ambient light.

Comparative Example 1 8 g of PR209 was put into 92 g of γ-butyrolactone, and dispersed with a homogenizer together with 200 g of glass beads at 7000 rpm for 30 minutes. Then, the glass beads were removed by filtration to obtain a solid content of 8%. A red pigment dispersion was obtained. The yield value of this dispersion was larger as it exceeded the measurable range of the viscometer, and the dispersion state was poor.

6 g of this red pigment dispersion and 12 g of the photosensitive resin solution used in Example 1 were mixed to obtain a red color paste. When the yield value of this color paste was measured, it was 9.8 × 10 ⁻² Pa, and the dispersion state of the pigment was poor. The surface roughness of the red colored film formed using this color paste in the same manner as in Example 1 was measured using a surface roughness profile measuring instrument.
And a large value was obtained, and the surface was rough.

Comparative Example 2 6.4 g of PR209 and 1.6 g of PO38 were charged into 92 g of γ-butyrolactone, and 200 g of glass beads were added.
Together with a homogenizer at 7000 rpm for 30 minutes.
After dispersion treatment for 1 minute, the glass beads were removed by filtration to obtain a red pigment dispersion having a solid content of 8%. The yield value of this dispersion was larger as it exceeded the measurable range of the viscometer, and the dispersion state was poor.

6 g of this red pigment dispersion and 12 g of the photosensitive resin solution used in Example 1 were mixed to obtain a red color paste. When the yield value of this color paste was measured, it was 2.9 × 10 ⁻² Pa, and the dispersion state of the pigment was poor. The surface roughness of the red colored film formed using this color paste in the same manner as in Example 1 was measured using a surface roughness profile measuring instrument, and the result was 32 nm.
And a large value was obtained, and the surface was rough.

Example 2 Instead of γ-butyrolactone, propylene glycol monomethyl ether acetate (P
A red pigment dispersion having a solid content of 8% was obtained in the same manner as in Example 1 except that GMEA) (relative dielectric constant 8) was used.
When the yield value of this dispersion was measured using a viscometer,
It was 6.7 × 10 ⁻³ Pa, and the dispersion state was good.

Further, an R color paste was obtained in the same manner as in Example 1 except that PGMEA and MMB were used in place of γ-butyrolactone in the photosensitive resin solution and cyclohexanone (dielectric constant: 18) was used. The yield value of the R color paste was 8.7 × 10 ⁻⁴ Pa, and the dispersion state of the pigment was good.

The red paste is applied on a non-alkali glass substrate by a spinner so that the average transmittance of the colored film from 480 nm to 530 nm is 10%.
And then heat-cured at 200 ° C. to form a red colored film. When measured using a microspectrophotometer, the average transmittance from 430 nm to 470 nm was 40%.
The threshold wavelength of the transmittance was 559 nm. The surface roughness measured using a surface roughness profile measuring instrument was 8 nm, and the surface was flat.

A red pixel pattern, a green pixel pattern and a green pixel pattern were formed on an alkali-free glass substrate on which a semi-transmissive reflection film made of a patterned aluminum thin film was formed in the same manner as in Example 1 except that the above-mentioned red paste was used. A color filter was fabricated by forming a blue pixel pattern.

Using this color filter, a transflective liquid crystal display panel was produced in the same manner as in Example 1.
This panel was able to reproduce bright and vivid red using ambient light.

Example 3 5.7 g of PR209 and 0.3 g of PR described in Example 1
209 sulfonated derivative, 2 g of PR242 (“NOVOPALM” Scarlet 4RF manufactured by Clariant) in an amount of 92 g
Of γ-butyrolactone into glass beads 200
g at room temperature using a homogenizer at 7000 rpm.
After the dispersion treatment for 0 minutes, the glass beads were removed by filtration,
A red pigment dispersion having a solid content of 8% was obtained. When the yield value of this dispersion was measured using a viscometer, it was 3.2 × 10
^-3 Pa, and the dispersion state was good.

Polyamic acid varnish (“Semico Fine” NH004, 15% solution of γ-butyrolactone manufactured by Toray)
46.7 g, surface conditioner (BYK36 manufactured by BYK Chemie)
1) 0.01 g of 13.3 g of γ-butyrolactone, 3-
It was dissolved in 40 g of methoxy-3-methyl-1-butanol to prepare a non-photosensitive resin solution.

8 g of the above red pigment dispersion and 10 g of the non-photosensitive resin solution were mixed to obtain a red color paste. The yield value of this color paste was measured to be 7.5 × 10
^-4 Pa, and the dispersion state of the pigment was good.

The red paste is applied on a non-alkali glass substrate by a spinner so that the average transmittance of the colored film from 480 nm to 530 nm is 10%.
, And then heat-cured at 230 ° C. to form a red colored film. When measured using a microspectrophotometer, the average transmittance from 430 nm to 470 nm was 39%.
The threshold wavelength of the transmittance was 565 nm. When the surface roughness of the colored film was measured using a surface roughness shape measuring instrument,
A value as small as 4 nm was obtained, and the surface was very flat.

The red color paste was applied by a spinner onto a reflection film composed of a silver / palladium / copper alloy thin film and an alkali-free glass substrate on which a resin black matrix in which carbon black was dispersed in a polyimide resin was formed, and dried by heating. . A positive photoresist solution ("Microposit" SR made by Shipley) is applied on the formed colored film.
C100-30CP) was applied by a spinner and dried to form a resist film. Ultraviolet exposure was performed through a mask, and the exposed portion was dissolved and removed with a 2% aqueous solution of tetramethylammonium hydroxide (TMAH).
After stripping off the resist film with methyl cellosolve acetate, the polyamic acid was converted to polyimide by heating at a higher temperature than during drying to form a red pixel pattern. Next, a green pixel pattern was similarly obtained using a green color paste. Then, using a blue color paste, a blue pixel pattern was formed in the same procedure.

The green and blue color pastes used were prepared by mixing 2 g of the green and blue pigment dispersions having a pigment concentration of 8% prepared in Example 1 with 18 g of the non-photosensitive resin solution, respectively. It is. After forming the blue pixel pattern, an overcoating agent (Clariant OCL)
-ES2) was applied by a spinner, and dried and cured by heating to form an overcoat film.

Using this color filter, the same operation as in Example 1 was performed to produce a reflective liquid crystal display panel.
This panel was able to reproduce bright and vivid red using ambient light.

[0068]

The red color paste of the present invention has good pigment dispersibility and excellent storage stability. The color filter of the present invention produced using this color paste has optical characteristics suitable for a reflective or transflective liquid crystal display panel. The reflective or transflective liquid crystal display panel of the present invention manufactured using this color filter can reproduce bright bright red using ambient light.

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Claims (14)

[Claims] 1. A red color paste comprising at least a quinacridone pigment, a sulfonated derivative of the quinacridone pigment, and a resin component. 2. The red color paste according to claim 1, wherein the pigment other than the quinacridone pigment contains at least one pigment selected from a red pigment, a purple pigment, and an orange pigment. 3. The quinacridone pigment is a red pigment PR2.
The red color paste according to claim 1, wherein the color paste is 09. 4. The red color paste according to claim 1, wherein the sulfonated derivative of the quinacridone pigment has an average of more than two sulfonic acid groups introduced per molecule. 5. The red color paste according to claim 1, wherein the sulfonated derivative of the quinacridone pigment is an amine salt. 6. The color paste according to claim 1, wherein the pigment dispersing solvent has a relative dielectric constant of 10 or more. 7. The red color paste according to claim 1, wherein the resin component contains an alkali-soluble resin. 8. The red color paste according to claim 1, wherein a photosensitive resin is contained as the resin component. 9. The red color paste according to claim 1, wherein the resin component contains a non-photosensitive resin. 10. The color paste having a yield value of 1 × 10
The red color paste according to any one of claims 1 to 9, which has a pressure of ^-2 Pa or less. 11. A color filter comprising red pixels obtainable from the red color paste according to claim 1. Description: 12. The method according to claim 1, wherein the red pixel is from 480 nm to 530n.
The color filter according to claim 11, wherein when the average transmittance at m is 10%, the average transmittance from 430 nm to 470 nm is 30% or more, and the threshold wavelength of the transmittance is 550 nm to 575 nm. 13. A reflection type liquid crystal display panel manufactured using the color filter according to claim 11. Description: 14. A transflective liquid crystal display panel manufactured using the color filter according to claim 11. Description: