JP2013182016A - Color filter for liquid crystal display device, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce outgassing generated from a color filter, to suppress panel bubbles due to the outgassing generated from the color filter, and to eliminate a display defect and a liquid crystal alignment unevenness due to bubble generation of a liquid crystal display device.SOLUTION: A color filter for a liquid crystal display device uses an overcoat material coated and formed on a black matrix and a coloring pixel. The overcoat material has a heat weight loss rate within 5% when heated at 230°C, for 3 hours, and the weight loss rate within 1% when heated at 120°C, for 1 hour.

Description

  The present invention relates to a color filter and a liquid crystal display device excellent in heat resistance, chemical resistance, and low outgas resistance.

  A liquid crystal display device has a structure in which a liquid crystal layer is sandwiched between a pair of substrates arranged opposite to each other, and is widely used in electronic devices such as monitors, projectors, mobile phones, and personal digital assistants (PDAs). . Liquid crystal display device control methods include twisted nematic (TN) mode, super twisted nematic (STN) mode, in-plane switching (IPS) mode, and transverse bend alignment (TBA). Various modes such as a Transverse Bend Alignment) mode have been developed.

  As a problem common to liquid crystal display devices, there is a bubble defect due to gas generated from a color filter. In a liquid crystal display device of a display system that applies a lateral electric field to a liquid crystal layer such as an IPS mode or a TBA mode, an electrode is not provided on a substrate provided with a filter layer such as a color filter. A technology that suppresses the gas component generated from the filter layer from entering the liquid crystal layer, although the gas component enters the liquid crystal layer and the concentration of impurity ions in the liquid crystal layer increases and display defects are likely to occur. Not yet established.

  A proposal has been made to control the amount of gas components generated from the color filter and suppress the generation of bubbles by changing the layer structure used in the color filter (Patent Document 1).

  In addition, by adding silica filler to the overcoat and reducing the ratio of the resin component, the proposal has been made to reduce the absolute amount of resin whose molecular bonds are broken by UV irradiation and suppress the generation of resin-derived gas. The filler content is limited, and sufficient results cannot be obtained (Patent Document 2).

Japanese Patent Laid-Open No. 11-133223 JP 2011-248050 A

  An object of the present invention is to reduce outgas generated from a color filter, suppress panel bubbles due to outgas generated from the color filter, and eliminate display defects and liquid crystal alignment unevenness due to generation of bubbles in the liquid crystal display device.

As means for solving the above problems, the invention according to claim 1 is a color filter for a liquid crystal display device using an overcoat material formed on a black matrix and colored pixels,
A liquid crystal display wherein the overcoat material has a thermal weight reduction rate of 5% or less when heated at 230 ° C. for 3 hours, and a thermal weight reduction rate of 1% or less when heated at 120 ° C. for 1 hour. This is a device color filter.

The invention according to claim 2 is characterized in that a flattening ratio expressed by the following formula of an overcoat layer formed by coating using the overcoat material is 90% or more. 2. A color filter for a liquid crystal display device according to 1.
[(Flattening ratio) = ((horn height before overcoat formation) − (horn height after overcoat formation)) / (horn height before overcoat formation)].

  The invention according to claim 3 is characterized in that the proportion of the aromatic ring-containing monomer in the resin composition constituting the overcoat material is 15% to 50%. 2. A color filter for a liquid crystal display device according to 2.

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

  According to the present invention, a gas component generated from a color filter can be suppressed, and a liquid crystal display device that is flat, has no display unevenness, and has high reliability can be provided.

It is a cross-sectional schematic diagram which shows the color filter of embodiment.

  The inventors of the present invention can improve the gas barrier property by selecting a resin component that is used for overcoating the gas component generated from the color filter layer, and controlling the content of the aromatic ring-containing monomer. It has been found that the gas component can be sufficiently prevented from entering the liquid crystal layer, and the present invention has been achieved.

  As a characteristic of the aromatic ring, the bond energy is high and the decomposition due to heat hardly occurs, and the effect of improving the density of the coating film formed by the stacking effect of the aromatic ring by π conjugation is obtained. Therefore, it is possible to improve the heat resistance and gas barrier properties of the overcoat film, and to impart the characteristics of reducing gas emission from the overcoat and suppressing gas emission from the color filter.

  When the ratio of the aromatic ring-containing monomer is less than 15%, the heat resistance effect of the overcoat is insufficient and the gas barrier effect is not obtained, which is not preferable. On the other hand, if it is 50% or more, the influence of the stacking effect of the aromatic ring becomes too great, and the flatness of the coating film is lost. For this reason, unevenness occurs at the time of alignment film rubbing, which is not preferable. From the above, the ratio of the aromatic ring-containing monomer in the resin is preferably 15% to 50%. Of the resin composition used for the overcoat, the ratio of the aromatic ring-containing monomer in the resin is 15 % To 50% of the resin composition for transparent overcoat film.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

A photosensitive black composition for forming the resin black matrix layer was prepared by mixing and stirring a mixture having the following composition (pigment concentration in solid content: 30.7%).
<Photosensitive black composition>
Carbon Black Dispersion: Gokoku Color Co., Ltd. (TPBK-2016) 28.50 parts by weight Resin: V259-ME (manufactured by Nippon Steel Chemical Co., Ltd.) (solid content 56.1% by weight) 10.30 parts by weight Monomer: DPHA ( Nippon Kayaku Co., Ltd.) 2.58 parts by weight Initiator: OXE-02 (Ciba Specialty Chemicals) 0.86 parts by weight Leveling agent: 1.30 parts by weight Solvent: Propylene glycol monomethyl ether acetate / ethyl-3 -Ethoxypropionate 92.00 parts by weight A black colored composition was applied on a transparent substrate by spin coating so as to have a film thickness of 1.5 μm. After drying at 100 ° C. for 3 minutes, the pattern exposure is performed with an exposure device to 200 mJ / cm ² , development is performed with an alkali developer for 60 seconds, and heat treatment is performed at 230 ° C. for 60 minutes for fixing. A grid-like black matrix was formed on a transparent substrate. The alkaline developer has the following composition. In the following examples and comparative examples, development is performed using this alkaline developer.

<Alkali developer>
Sodium carbonate 1.5% by weight Sodium hydrogen carbonate 0.5% by weight Anionic surfactant (“Perilex NBL” manufactured by Kao Corporation) 8.0% by weight Water 90.0% by weight
A colored layer comprising red, green and blue colored compositions will be described.
<Red coloring composition>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a red pigment dispersion.
Red pigment: C.I. I. Pigment Red 254
(“Ilgar For Red B-CF” manufactured by Ciba Specialty Chemicals) 18 parts red pigment: C.I. I. PigmentRed177
(Ciba Specialty Chemicals “Chromophthal Red A2B”) 2 parts dispersant (Ajinomoto Fine Techno “Ajispar PB821”) 2 parts acrylic varnish (solid content 20%) 50 parts Then, the mixture was stirred and mixed, and filtered through a 5 μm filter to obtain a red colored composition.
72 parts caprolactone modified dipentaerythritol hexaacrylate
(“Kayarad DPCA-30” manufactured by Nippon Kayaku Co., Ltd.) 8 parts dipentaerythritol hexaacrylate
(“Kayarad DPHA” manufactured by Nippon Kayaku Co., Ltd.) 10 parts methylated melamine resin (“MW30” manufactured by Sanwa Chemical Co., Ltd.) 10 parts photoinitiator (“Irgacure 907” manufactured by Ciba Specialty Chemicals) 3 parts sensitizer ("EAB-F" manufactured by Hodogaya Chemical Co., Ltd.) 1 part cyclohexanone 253 parts <green coloring composition>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using a glass bead having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a green pigment dispersion.
Green pigment: C.I. I. Pigment Green 36
(Toyo Ink Mfg. Co., Ltd. “Lionol Green 6YK” 16 parts yellow pigment: CI Pigment Yellow 150
("Funchon First Yellow Y-5688" manufactured by Bayer) 8 parts dispersant ("Disperbyk-163" manufactured by Big Chemie) 2 parts acrylic varnish (solid content 20%) 102 parts Thereafter, 128 parts of the above dispersion were used, and A mixture having the following composition was stirred and mixed to be uniform, and then filtered through a 5 μm filter to obtain a green colored composition.
Trimethylolpropane triacrylate:
(“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.) 14 parts photoinitiator: (“Irgacure 907” manufactured by Ciba Specialty Chemicals) 4 parts sensitizer: (“EAB” manufactured by Hodogaya Chemical Co., Ltd.) -F ") 2 parts Solvent: 257 parts cyclohexanone <blue coloring composition>
A mixture having the following composition was uniformly stirred and mixed, then dispersed in a sand mill for 5 hours using glass beads having a diameter of 1 mm, and then filtered through a 5 μm filter to prepare a blue pigment dispersion.
Blue pigment: C.I. I. Pigment Blue 15
("Rionol Blue ES" manufactured by Toyo Ink Co., Ltd.) 30 parts Purple Pigment: C.I. I. Pigment Violet 23
("Paliogen Violet 5890" manufactured by BASF) 2 parts dispersant ("Sols Birds 20000" manufactured by Zeneca) 6 parts Acrylic varnish (solid content 20%) 200 parts Thereafter, the mixture having the following composition was stirred and mixed to be uniform. Then, it filtered with a 5 micrometers filter and obtained the blue coloring composition.
238 parts of the above dispersion trimethylolpropane triacrylate:
(“NK ESTER ATMPT” manufactured by Shin-Nakamura Chemical Co., Ltd.) 19 parts Photoinitiator: (“Irgacure 907” manufactured by Ciba Specialty Chemicals) 4 parts sensitizer: (“EAB” manufactured by Hodogaya Chemical Co., Ltd.) -F ") 2 parts Solvent: 214 parts of cyclohexanone A colored layer serving as a pixel was formed in the following manner using the obtained red coloring composition, green coloring composition, and blue coloring composition. On the transparent substrate on which the resin black matrix layer was formed, the red coloring composition was applied by spin coating so as to have a film thickness of 2 μm. After drying, striped pattern exposure was performed with an exposure machine, development was performed with an alkaline developer for 90 seconds, and heating was performed at 230 ° C. for 20 minutes to fix, and striped red colored pixels 3 were formed on the transparent substrate.

  Next, the green coloring composition is similarly applied by spin coating so that the film thickness becomes 2 μm. After drying, the striped colored layer was exposed and developed in an exposure machine at a location shifted from the red colored layer, thereby forming a green colored image 4 adjacent to the red colored layer.

  Further, in the same manner as red and green, the blue colored composition 5 was formed with a blue colored image 5 adjacent to the red colored layer and the green colored layer with a film thickness of 2 μm.

  Subsequently, a resin composition for forming the overcoat layer 6 applied and formed on the black matrix 2 and the colored pixels will be described.

<Synthesis of Resin 1>
The following materials were added into a 5-neck reaction vessel having an internal volume of 2 liters, and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a resin 1 solution.
Propylene glycol monomethyl ether acetate (PGMAc) 800 g benzyl methacrylate (BzMA, aromatic ring-containing monomer) 30 g butyl methacrylate (BMA) 78 g methacrylic acid (MAA) 44 g hydroxyethyl methacrylate (HEMA) 48 g azobisisobutyronitrile (AIBN) 4 g The mixture was heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a resin 1 solution.

<Photosensitive composition for overcoat film (1)>
Solid mass,
Resin 1 100 parts by mass of ethylenically unsaturated compound:
KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 60 parts by mass (C) Photopolymerization initiator:
8.4 parts by mass of Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist would be 30% by mass, and (B) the ethylenic content relative to the solid content of resin 1 was reduced. The overcoat film photosensitive composition (1) was prepared so that the mass ratio of the solid content of the saturated compound was 0.6.

The above-described photosensitive composition for overcoat film (1) was spin-coated on the glass substrate on which the above-mentioned colored layer was formed so as to have a film thickness of 1.5 μm, and dried at 90 ° C. for 5 minutes. 150 mJ / cm ^{2 was} irradiated with light from a high-pressure mercury lamp through a photomask for forming an overcoat. In addition, it exposed with the space | interval (exposure gap) of a photomask and a glass substrate being 100 micrometers. Then, it developed using the developing solution similar to preparation of the above-mentioned colored layer. After washing with water, baking was performed at 230 ° C. for 30 minutes to form an overcoat film on the colored layer.

<Photosensitive resin composition for spacer formation>
Resin a was synthesized by adding the following materials into a five-necked reaction vessel having an internal volume of 2 liters and heating at 80 ° C. for 6 hours while blowing nitrogen to obtain a polymer solution of GMA.
Propylene glycol monomethyl ether acetate (PGMAc) 686.0 g Glycidyl methacrylate (GMA) 332.0 g Azobisisobutyronitrile (AIBN) 6.6 g
Next, the following materials were added to the obtained GMA polymer solution and heated at 100 ° C. for 24 hours while blowing air to obtain an acrylic acid adduct solution of GMA resin.
Acrylic acid (AA) 168 g Metoquinone (MQ) 0.05 g Triphenylphosphine (TPP) 0.5 g
Next, 186 g of tetrahydrophthalic anhydride was added to the resulting acrylic acid adduct solution of GMA resin and heated at 70 ° C. for 10 hours to obtain a resin a solution.

<Adjustment of photosensitive resin composition>
The photosensitive resin composition was prepared by diluting with cyclohexanone so that the solid content in the resist was 30% by weight.
Pentaerythritol triacrylate:
("PET-30" manufactured by Nippon Kayaku Co., Ltd.) 80 parts by weight resin a: 20 parts by weight photopolymerization initiator ("Irgacure 907" manufactured by BASF) 14 parts by weight The photosensitive resin composition for spacer formation The spacer 7 was formed by using this. A resin black matrix 2, a red colored pixel 3, a green colored pixel 4, a blue colored pixel 5, and a transparent conductive layer are formed on the glass 1, and the photosensitive resin composition is spin-coated so that the final film thickness is 4 μm. And dried at 90 ° C. for 2 minutes. Next, light from a high-pressure mercury lamp was irradiated at a dose of 100 mJ / cm ² through a photomask for forming a circular photospacer having a mask opening diameter of 8 μmφ.

  Note that the exposure (exposure gap) between the photomask and the substrate was 100 μm. Thereafter, development is performed using an alkali developer similar to the formation of the resin black matrix layer and the colored layer, and after washing with water, photobaking is performed at 230 ° C. for 30 minutes to form a photo spacer, and the color shown in FIG. A filter was obtained.

Furthermore, after the obtained color filter was washed with a neutral detergent, an alignment film made of polyimide resin was applied by a printing method and heated on a hot plate at 250 ° C. for 10 minutes. The film thickness is 0.
It was 07 μm. Thereafter, the color filter 1 was rubbed, the sealing agent was applied by a dispensing method, and heated on a hot plate at 90 ° C. for 10 minutes.

  On the other hand, the substrate on which the TFT array is formed on the glass 1 is washed in the same manner, and then an alignment film is applied and heated. Thereafter, the sealant is cured by superimposing it on the color filter substrate and heating at 160 ° C. for 90 minutes while applying pressure in an oven. The cell was left at 120 ° C. and 13.3 Pa for 4 hours, then in nitrogen for 0.5 hour, and then liquid crystal was injected again under vacuum. Liquid crystal injection was carried out by placing the cell in a chamber and reducing the pressure to 13.3 Pa at room temperature, then immersing the liquid crystal injection port in liquid crystal and returning to normal pressure using nitrogen.

  After the liquid crystal injection, the liquid crystal injection port was sealed with an ultraviolet curable resin. Next, a polarizing plate was affixed on the outer side of the glass substrate which consists of two cells, and the cell was completed. Further, the obtained cell was modularized to complete a horizontal electric field drive liquid crystal display device. The overcoat layer flattening rate is 92%, the overweight material has a thermal weight decrease rate of 4% and within 5% when heated at 230 ° C. for 3 hours, and the thermal weight when heated at 120 ° C. for 1 hour. The reduction rate is 1%, and as a result of observing the obtained liquid crystal display device, there is no generation of bubbles even after storage for 100 hours in a high humidity state at 40 ° C. and 90% humidity, and there is no display defect. I understood.

  The same procedure as in Example 1 was performed except that the overcoat layer photosensitive composition (2) having a different content of the aromatic ring-containing monomer was used for forming the overcoat layer 6 and the color filter 2 was obtained. Thus, a liquid crystal display device was produced. The overcoat layer flattening rate is 91%, the overcoat material has a thermal weight reduction rate of 3% and within 5% when heated at 230 ° C for 3 hours, and the thermal weight when heated at 120 ° C for 1 hour. The reduction rate was 0.6% and within 1%. As a result of observing the obtained liquid crystal display device, it was found that there was no display defect. As a result of observing the obtained liquid crystal display device, it was found that no bubbles were generated even after storage for 100 hours in a high humidity state at 40 ° C. and a humidity of 90%, and there was no display defect.

<Synthesis of Resin 2>
The following materials were added into a 5-neck reaction vessel having an internal volume of 2 liters, and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a resin 2 solution.
Propylene glycol monomethyl ether acetate (PGMAc) 800 g benzyl methacrylate (BzMA, aromatic ring-containing monomer) 50 g butyl methacrylate (BMA) 46 g methacrylic acid (MAA) 26 g hydroxyethyl methacrylate (HEMA) 28 g azobisisobutyronitrile (AIBN) 4 g
<Photosensitive composition for overcoat film (2)>
Solid mass,
Resin 2 100 parts by mass of ethylenically unsaturated compound:
KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 60 parts by mass (C) Photopolymerization initiator:
8.4 parts by mass of Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist would be 30% by mass, and (B) the ethylenic content relative to the solid content of resin 2 was reduced. The overcoat film photosensitive composition (2) was prepared so that the mass ratio of the solid content of the saturated compound was 0.6.
<Comparative Example 1>
The same procedure as in Example 1 was performed except that the overcoat layer photosensitive composition (3) having a different aromatic ring-containing monomer content was used for forming the overcoat layer 6 to obtain the color filter 3. Thus, a liquid crystal display device was produced. The overcoat layer flattening rate was 94%, but the thermal weight when the overcoat material was heated at 230 ° C. for 3 hours also exceeded 10% and 5%. As a result of observing the obtained liquid crystal display device, it was found that there was no display defect. As a result of observing the obtained liquid crystal display device, bubbles were generated due to generation of bubbles after being stored in a high humidity state at 40 ° C. and 90% humidity for 100 hours.

<Synthesis of Resin 3>
The following materials were added to a 5-liter reaction vessel having an internal volume of 2 liters, and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a resin 3 solution.
Propylene glycol monomethyl ether acetate (PGMAc) 800 g benzyl methacrylate (BzMA, aromatic ring-containing monomer) 10 g butyl methacrylate (BMA) 87 g methacrylic acid (MAA) 49 g hydroxyethyl methacrylate (HEMA) 54 g azobisisobutyronitrile (AIBN) 4 g
<Photosensitive composition for overcoat film (3)>
Solid mass,
Resin 3 100 parts by mass of ethylenically unsaturated compound:
KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 60 parts by mass (C) Photopolymerization initiator:
8.4 parts by mass of Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist would be 30% by mass, and (B) the ethylenic content relative to the solid content of resin 3 was reduced. The overcoat film photosensitive composition (3) was prepared so that the mass ratio of the solid content of the saturated compound was 0.6.
<Comparative example 2>
Except having obtained the color filter 4 using the overcoat layer photosensitive composition (4) in which the content of the aromatic ring-containing monomer was changed, the procedure was exactly the same as in Example 1. Thus, a liquid crystal display device was produced. The overcoat layer flattening rate was 87%, not reaching 90%. As a result of observing the obtained liquid crystal display device, display unevenness considered to be alignment rubbing unevenness was observed.

<Synthesis of Resin 4>
The following materials were added to a 5-liter reaction vessel having an internal volume of 2 liters, and heated at 80 ° C. for 6 hours while blowing nitrogen to obtain a resin 4 liquid.
Propylene glycol monomethyl ether acetate (PGMAc) 800 g benzyl methacrylate (BzMA, aromatic ring-containing monomer) 60 g butyl methacrylate (BMA) 64 g methacrylic acid (MAA) 36 g hydroxyethyl methacrylate (HEMA) 40 g azobisisobutyronitrile (AIBN) 4 g
<Photosensitive composition for overcoat film (4)>
Solid mass,
Resin 4 100 parts by mass of ethylenically unsaturated compound:
KAYARAD DPHA (manufactured by Nippon Kayaku Co., Ltd.) 60 parts by mass (C) Photopolymerization initiator:
8.4 parts by mass of Irgacure 907 (manufactured by Ciba Specialty Chemicals) was diluted with cyclohexanone so that the solid content in the resist would be 30% by mass, and (B) the ethylenic content relative to the solid content of resin 4 was reduced. The mass ratio of the solid content of the saturated compound is 0.6.
The overcoat film photosensitive composition (4) was prepared.

  The results are shown in Table 1.

The ratio of the aromatic ring-containing monomer is an overcoat material having a thermal weight reduction rate of 5% or less when heated at 230 ° C. for 3 hours and a thermal weight reduction rate of 1% or less when heated at 120 ° C. for 1 hour. As a result of observing the obtained liquid crystal display device, it was found that bubbles using 15% to 50% overcoat material were free of bubbles even after being stored at high humidity, and there was no display failure. Further, when the flattening rate was 90% or more, there was no occurrence of initial alignment rubbing unevenness.

1 ... Glass 2 ... Black matrix (BM)
3 ... Colored pixels (Red)
4 ... Colored pixels (Green)
5 ... Colored pixels (Blue)
6 ... Overcoat layer 7 ... Spacer

Claims (4)

A color filter for a liquid crystal display device using an overcoat material applied and formed on a black matrix and colored pixels,
A liquid crystal display wherein the overcoat material has a thermal weight reduction rate of 5% or less when heated at 230 ° C. for 3 hours, and a thermal weight reduction rate of 1% or less when heated at 120 ° C. for 1 hour. Color filter for equipment. 2. The color filter for a liquid crystal display device according to claim 1, wherein the overcoat layer formed by coating using the overcoat material has a flattening ratio represented by the following formula of 90% or more.
[(Planarization ratio) = ((Thorn height before overcoat formation) − (Thorn height after overcoat formation)) / (Thorn height before overcoat formation)]   The color filter for a liquid crystal display device according to claim 1 or 2, wherein the ratio of the aromatic ring-containing monomer in the resin composition constituting the overcoat material is 15% to 50%.   A liquid crystal display device using the color filter for a liquid crystal display device according to claim 1.