JPH10197880A - Sealant and liquid crystal display - Google Patents

Abstract

(57) [Problem] To provide a sealant having a high light-shielding property and a liquid crystal display device having excellent image display quality. SOLUTION: A transparent substrate, a black matrix formed in a predetermined pattern in a display region on the transparent substrate and a colored layer composed of a plurality of colors, and a black matrix formed in a frame portion located outside the display region are provided. At least a color filter substrate is provided, and a predetermined gap is provided by a sealing member formed by arranging a sealing agent containing at least a resin component and light-shielding fine particles so as to be in contact with a black matrix located at a frame portion. The substrate is opposed to the substrate, and a liquid crystal is sealed in the gap to obtain a liquid crystal display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding sealant and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, a color liquid crystal display device has attracted attention as a flat panel display. In general,
A color liquid crystal display device includes a color filter substrate having a black matrix and a coloring layer composed of a plurality of colors (usually three primary colors of red (R), green (G), and blue (B)) and a counter electrode substrate. And a liquid crystal layer sandwiched between them. The color image is obtained by controlling the light transmittance of the liquid crystal layer in a portion corresponding to each pixel of the colored layers R, G, and B of each color. Therefore, the above color filter substrate is indispensable for the color liquid crystal display device,
This is an important member that determines the display quality of the color liquid crystal display device itself.

Conventionally, as a black matrix of a color filter substrate, one obtained by patterning chromium or chromium oxide formed by sputtering or vapor deposition by photolithography has been used. In addition, the coloring layer of the color filter substrate, a dyeing substrate is applied, a dyeing method for dyeing a pattern formed by exposing and developing through a photomask, a coloring pigment is dispersed in a photosensitive resist in advance, A pigment dispersion method of exposing and developing through a photomask,
Further, it is formed by a printing method of printing each color with a printing ink or the like. Further, a transparent conductive film is formed on the transparent substrate, a positive resist layer is formed on the transparent conductive film, and exposure is performed through a mask having a predetermined pattern. After exposing a predetermined portion of the film, and then immersing the transparent substrate in an electrodeposition liquid of a predetermined color, a current is supplied from the transparent conductive film around the transparent substrate to perform electrodeposition to form a colored layer or a black matrix. There is an electrodeposition method.

[0004]

In the above-described color filter substrate, the black matrix includes a black matrix formed in a predetermined pattern together with a colored layer in a display region, and a black matrix formed in a frame portion located outside the display region. There is a black matrix formed. Then, a seal member is formed using a sealant so as to contact the black matrix formed on the frame portion, and the gap between the color filter substrate and the counter electrode substrate is sealed by the seal member. However, if there is a defect such as a pinhole in the black matrix formed in the frame,
There is a problem that the light of the backlight of the color liquid crystal display device passes through the defective portion of the black matrix and further passes through the sealing member, which impairs the image display quality of the liquid crystal display device.

The present invention has been made in view of the above circumstances, and has as its object to provide a sealant having a high light-shielding property and a liquid crystal display device having excellent image display quality.

[0006]

In order to achieve the above object, the present invention provides a sealant for filling a desired liquid into a gap between a pair of substrates facing each other and sealing the same with at least a resin component. And light-shielding fine particles.

The light-shielding fine particles are constituted so as to be at least one of carbon black and resin-coated carbon black.

According to the present invention, there is provided a liquid crystal display device having a color filter substrate and a counter electrode substrate facing each other via a sealing member, and a liquid crystal layer sealed between the two substrates, wherein the color filter substrate is transparent. A substrate, a black matrix formed in a predetermined pattern in a display area on the transparent substrate and a colored layer formed of a plurality of colors, and at least a black matrix formed in a frame located outside the display area; The seal member is configured such that the sealant according to claim 1 or 2 is disposed so as to be in contact with the black matrix located at the frame portion.

In the present invention as described above, light-shielding properties are imparted to the sealant by the light-shielding fine particles, and such a sealant is disposed so as to be in contact with the black matrix located at the frame of the color filter substrate. The gap between the color filter substrate and the opposing electrode substrate facing each other is sealed by the formed sealing member, and even if there is a defect in the black matrix located in the frame portion, unnecessary light passing through this defective portion is sealed. The member effectively shuts off.

[0010]

Embodiments of the present invention will be described below.

The sealant of the present invention contains at least a resin component and light-shielding fine particles. As the resin component constituting the sealing agent, a known resin component conventionally used as a sealing agent can be used. Specifically, one or more of bisphenol F type, bisphenol A type diglycidyl ether, resorcinol diglycidyl ether resin, phenol novolak type epoxy resin, triphenolmethane type epoxy resin and the like can be used as a resin component. it can.

The light-shielding fine particles constituting the sealant of the present invention include carbon black, resin-coated carbon black, iron oxide, titanium oxide, aniline black, and the like.
One or more of cyanine black and the like can be used. The above carbon black preferably has an average particle size of about 0.01 to 0.5 μm, and the resin-coated carbon black is obtained by adding polyoxyethylene alkyl ether, styrene-
A resin obtained by grafting a resin such as an isopropenyl isocyanate copolymer (50 to 250 parts by weight of a grafted product with respect to 100 parts by weight of carbon black) can be used. In particular, by using the resin-coated carbon black as the light-shielding fine particles, it is possible to impart excellent electrical insulation to the sealant.

In the sealant of the present invention, the light-shielding fine particles are preferably contained in an amount of 5 to 10 parts by weight based on 100 parts by weight of the resin component. When the content of the light-shielding fine particles is less than 5 parts by weight, the light-shielding property of the sealant becomes insufficient. On the other hand, when the content exceeds 10 parts by weight, the adhesion strength and breaking strength of the sealant become insufficient, and Is also undesirably reduced.

The sealant of the present invention may contain, if necessary, an inorganic filler (talc, mica, etc.), a silane coupling agent (aminosilane, epoxysilane, etc.), a solvent (cellosolve, carbitols, etc.), a curing accelerator. An additive such as an agent (imidazoles, triphenylphosphine bicycloundecene, trisdimethylaminomethylphenol, etc.) can be contained. In this case, based on 100 parts by weight of the resin component, the inorganic filler is in the range of 10 to 40 parts by weight, the silane coupling agent is in the range of 1 to 10 parts by weight, the solvent is in the range of 1 to 10 parts by weight, and the curing is performed. The accelerator is preferably contained in the range of 0.1 to 10 parts by weight.

Next, the liquid crystal display device of the present invention will be described. FIG. 1 is a partial sectional view showing one embodiment of the liquid crystal display device of the present invention. 1, in a liquid crystal display device 1 of the present invention, a color filter substrate 2 and a counter electrode substrate 3 are opposed at a predetermined interval, and a frame portion (peripheral portion) is a sealing member 4.
And a liquid crystal layer 5 having a thickness of about 5 to 10 μm is formed between both substrates. Polarizing plates 6 are provided outside the color filter substrate 2 and the counter electrode substrate 3, respectively.

The color filter substrate 2 constituting the liquid crystal display device 1 of the present invention has a black matrix 16 and a colored layer 17 formed on a transparent substrate 11 via a transparent conductive film 12 in a predetermined pattern. On this, a transparent electrode 18 for driving liquid crystal and an alignment layer 19 are formed. The transparent conductive film 12 includes a display area A in which the black matrix 16 and the colored layer 17 are formed, and a display area A
And a frame portion B located around the frame. Then, a sealing agent is provided so as to abut on the black matrix 16a located in the frame portion B of the black matrix 16 to form the sealing member 4, and the color filter substrate 2 and the counter electrode substrate 3 are formed by the sealing member 4.
Of the frame B (peripheral portion) is sealed. The sealant forming the seal member 4 is the above-described sealant of the present invention, and the black matrix 1 located at the frame portion B is used.
Even if there is a defect in 6a, unnecessary light passing through this defective portion is effectively blocked by the seal member 4. Therefore, regardless of the presence or absence of a defect of the black matrix in the frame portion B of the liquid crystal display device, the amount of transmitted light in the frame portion B can always be extremely low, thereby stably maintaining good image display quality. be able to.

In the liquid crystal display device 1 of the present invention as described above, the black matrix 16 can be formed from a resin containing at least one of a dye, a pigment, carbon black, and metal particles. The thickness of the black matrix is usually 1.0 to 3.0 μm
Degree. Further, the black matrix 16 may be formed of a metal or a metal oxide.

The coloring layer 17 has a red pattern 17R,
The green pattern 17G and the blue pattern 17B are arranged in a desired form such as a mosaic type, a stripe type, a triangle type, a four-pixel arrangement type, and the black matrix 16 is provided between the colored patterns and outside the colored layer 17 forming region. It is provided in the frame part B.

On the other hand, the counter electrode substrate 3 constituting the liquid crystal display device 1 of the present invention has a transparent electrode 21 for driving liquid crystal and a thin film transistor (TFT) 23 on a transparent substrate 21 and is oriented so as to cover the transparent electrode 22. A layer 24 has been formed. The counter electrode substrate 3 has a thin film transistor (T
FT) 23, a gate line group (not shown) for opening / closing, a signal line group (not shown) for supplying a video signal, and transfer from a take-out portion at a corner on the color filter substrate side (transfer portion (1 to Voltage supply lines (not shown) to the color filter electrodes provided at the three extraction portions are provided.

The transparent substrates 11 and 21 constituting the color filter substrate 2 and the counter electrode substrate 3 of the above-described liquid crystal display device 1 are made of rigid material such as quartz glass, Pyrex glass, synthetic quartz plate or the like. A flexible material having flexibility, such as a transparent resin film or an optical resin plate, can be used. Among them, especially Corning 70
59 glass is a material having a low coefficient of thermal expansion, excellent in dimensional stability and workability in high-temperature heat treatment, and is a non-alkali glass containing no alkali component in the glass. Suitable for display devices. Also, “AN63” manufactured by Asahi Glass Co., Ltd., which has a low BaO content and excellent chemical resistance.
5 "and" OA2 "manufactured by NEC Corporation are also preferably used.

The transparent conductive film 12 and the transparent electrodes 18 and 22 of the liquid crystal display device 1 are made of indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO).
And an alloy thereof, etc., and formed by a general film forming method such as a sputtering method, a vacuum evaporation method, and a CVD method. The thickness of the transparent conductive film 12 and the transparent electrodes 18 and 22 is 0.01 to 1 μm, preferably 0.1 to 1 μm.
It is about 03 to 0.5 μm.

In the liquid crystal display device shown in FIG. 1, the transparent conductive film 12 is formed over the display area A and the frame portion B. 12a is exposed. In such a liquid crystal display device of the present invention, the end portion 12a of the transparent conductive film and the transparent conductive film 12 located in the display region A may be electrically insulated.

Further, the alignment layers 19 and 24 constituting the liquid crystal display device 1 are layers containing at least one of organic compounds of polyimide type, polyamide type, polyurethane type and polyurea type, and have a thickness. 0.01-1μ
m, preferably about 0.03 to 0.5 μm. The alignment layers 19 and 24 are coated by a known coating method such as various printing methods, and then baked and then subjected to an alignment treatment (rubbing).

In the above embodiment, the driving method is TF
Although the T active matrix system is used, the liquid crystal display device of the present invention is not limited to this. For example, a system such as a simple matrix or a segment, MIM
It is needless to say that an active matrix method using a two-terminal element such as (metal / insulator / metal) may be used.

[0025]

Next, the present invention will be described in more detail with reference to examples. (1) Preparation of Sealant Coated carbon black having an average particle size of 0.05 μm as light-shielding fine particles (CX-GLT-20 manufactured by Nippon Shokubai Co., Ltd.)
A liquid obtained by dispersing a predetermined amount of (carbon black content: 33% by weight) in 120 g of toluene is mixed with 100 g of a sealant (XN-21-S manufactured by Mitsui Toatsu Co., Ltd.) as a resin component and uniformly dispersed. did. Next, the dispersion was subjected to a reduced pressure treatment (1.0 × 10 ⁻³ Torr) to remove toluene, and seven types of sealants A1 to A7 having a viscosity of about 400 cp were obtained. Resin component 1 in these sealants A1 to A7
Table 1 below shows the content (parts by weight) of the coated carbon black relative to 00 parts by weight.

Further, XN-21-S manufactured by Mitsui Toatsu Co., Ltd. containing no light-shielding fine particles was used as a comparative sealant B.

On the other hand, a sealing agent C (viscosity at 25 ° C. = 300 poise) having the following composition was prepared using a vacuum kneader.

Composition of sealant C Epibis liquid epoxy resin (Epiclon 850, manufactured by Dainippon Ink and Chemicals, Inc.) 100 parts by weight Phenol salt of diazabicycloundecene (curing agent) U-CAT SA-1) ... 5 parts by weight-Talc (inorganic filler) ... 30 parts by weight-Epoxysilane (silane coupling agent) (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.) ... 0.5 parts by weight-Ethyl cellosolve ... 10 parts by weight-Polymer grafted carbon ... 10 parts by weight The above polymer grafted carbon is composed of 20 parts by weight of carbon black (MA-100 manufactured by Mitsubishi Kasei Kogyo KK) and an isocyanate group as a reactive group. -Styrene-isopropenyl isocyanate copolymer having a molar ratio of 20
0: 5) 40 parts by weight of 1 part using a Labo Plastmill
It was prepared by kneading and reacting at 60 ° C. and 100 rpm.

For comparison, a sealant D was prepared in the same manner as the sealant C except that the polymer-grafted carbon was not contained. (2) Preparation of Color Filter Substrate First, a 1.1 mm thick glass substrate (Corning 70
A transparent conductive film made of indium tin oxide (ITO) was formed on the entire surface of (59 glass). Next, after applying a photosensitive resist on the transparent conductive film and exposing and developing through a mask corresponding to a black matrix pattern, the above glass substrate is immersed in an electrodeposition bath in which a black pigment is dispersed, and the transparent substrate is transparent. A black electrodeposition material was deposited by applying a voltage to the conductive film, washed sufficiently with water, and dried to form a black matrix having a thickness of 1.0 μm.

Next, a photosensitive resist is applied on the transparent conductive film, exposed and developed through a mask corresponding to a red pattern, and then the glass substrate is immersed in an electrodeposition bath in which a red pigment is dispersed. A voltage was applied to the transparent conductive film to precipitate a red electrodeposition material, washed sufficiently with water, and dried to a thickness of 1.0 μm.
m red pattern was formed. Similarly, a green pattern and a blue pattern were formed. Thereafter, the color filter substrate was manufactured by baking at 200 ° C. for 60 minutes.

In this color filter substrate, a black matrix is formed in a predetermined pattern on each of the display area A and the frame B as shown in FIG. The rays intentionally caused pinhole defects. (3) Production of liquid crystal display device On the black matrix formed on the frame of the color filter substrate produced in (2), the sealant (A, B, C, D) prepared in (1) is applied. It was applied with a dispenser and prebaked at 90 ° C. for 30 minutes to form a seal member. Then, the color filter substrate provided with the above sealing member is overlaid on a counter electrode substrate on which a transparent electrode for driving liquid crystal and a thin film transistor (TFT) are provided on a glass substrate and an alignment layer is formed so as to cover the transparent electrode. Then, the sealing member was cured at 200 ° C. for 3 hours. The thickness of the cured sealing member was 4.5 μm. (4) Evaluation The optical density (O
D value) with a colorimeter (AH- manufactured by Olympus Optical Industries, Ltd.)
The results measured in 2) are shown in Table 1 below. In addition, the adhesion strength of the sealing member to the color filter substrate and the counter electrode substrate, the breaking strength of the sealing member, the volume resistance, the water resistance, and the heat resistance were measured and evaluated as follows, and the results are shown in Table 1 below.

A method for measuring the adhesion strength A jig is adhered to the outside of the color filter substrate and the outside of the counter electrode substrate of the liquid crystal display device placed horizontally, and both substrates are pulled up and down vertically through the jig. The tensile strength (kgf) when both substrates were peeled was determined by the peeling area (cm
^The adhesive strength was calculated by dividing by ² ).

Measuring Method of Breaking Strength Two pieces of glass (Corning 7059 glass having a thickness of 1.1 mm, manufactured by Corning Incorporated) are sealed with a sealant, and a tensile test similar to the above-mentioned adhesion strength measurement is performed. The breaking strength was defined as the breaking strength.

Measurement method of volume resistance Insulation resistance meter Electrometer 6 manufactured by Toyo Technica Co., Ltd.
517.

Evaluation method for water resistance A sample similar to the one for measuring the breaking strength was prepared, and 2 atm.
After treatment at 80 ° C. and 90% RH for 100 hours, a tensile test similar to the measurement of the breaking strength was performed. The results are shown in comparison with the breaking strength.

A cell assembly was formed by facing a glass substrate on which ITO was patterned on a base glass (1.159 mm thick 7059 glass manufactured by Corning), and the voltage holding ratio before and after the treatment under the same conditions was measured and compared. did.

Evaluation method of heat resistance A sample similar to the measurement of the breaking strength was prepared, and after the heat treatment at 120 ° C. for 100 hours, a tensile test similar to the measurement of the breaking strength was performed. The results are shown in comparison with the breaking strength.

A cell assembly was formed by facing a glass substrate on which ITO was patterned on plain glass (1.159 mm thick 7059 glass manufactured by Corning Incorporated), and the voltage holding ratio before and after the treatment under the same conditions was measured and compared. did.

Further, the frame of the above-mentioned liquid crystal display device was irradiated with linear light from the counter electrode substrate side, and the light transmittance to the color filter substrate side at the pinhole defect formation position was measured. It was shown to.

[0040]

[Table 1] As shown in Table 1, sealants A3 to 5 containing not less than 5 parts by weight of light-shielding fine particles with respect to 100 parts by weight of the resin component.
The seal members using A7 and C exhibited good OD values. Reflecting this result, the light transmittance at the pinhole defect forming portion of the frame portion of the liquid crystal display device is 0.1% in the seal member using the sealants A3 to A7 and C.
It was 8% or less, and it was confirmed that the light-shielding property of the seal member using the sealant of the present invention was extremely high.

On the other hand, the sealing agents A-3 to A-5 and the sealing agent C having the content of the light-shielding fine particles in the range of 5 to 10 parts by weight based on 100 parts by weight of the resin component have the adhesion strength, the breaking strength and the water resistance. , Heat resistance, both are comparative sealant B,
The level was almost the same as that of the seal member using D, and it was confirmed that the seal member of the liquid crystal display device can be sufficiently used practically.

[0042]

As described above in detail, according to the present invention, since the sealant contains at least a resin component and light-shielding fine particles, the sealant is used to fill the gap between a pair of transparent substrates facing each other. When the desired liquid is filled and sealed, light is prevented from passing through both substrates at the location where the sealant is provided.

By using at least one kind of light-shielding fine particles of carbon black and resin-coated carbon black, the sealing agent has a high light-shielding property. In particular, resin-coated carbon black is contained as light-shielding fine particles. Sealants have excellent insulating properties.

Further, a transparent substrate, a black matrix formed in a predetermined pattern in a display area on the transparent substrate, and a colored layer composed of a plurality of colors, and a black matrix formed in a frame located outside the display area. A color filter substrate having at least a sealing member formed by arranging the sealant of the present invention so as to contact the black matrix located in the frame portion to provide a predetermined gap to face the counter electrode substrate. In a liquid crystal display device in which liquid crystal is sealed in a gap, even if there is a defect in the black matrix located in the frame portion, unnecessary light passing through the defective portion is blocked by the sealing member, so that excellent image display quality is obtained. Have.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view near an end showing one embodiment of a liquid crystal display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device 2 ... Color filter substrate 3 ... Counter electrode substrate 4 ... Seal member 5 ... Liquid crystal layer 6 ... Polarizing plate 11, 21 ... Transparent substrate 12 ... Transparent conductive film 13, 13B ... Resin layer 16 ... Black matrix 17 ( 17R, 17G, 17B) ... Colored layer 18,22 ... Transparent electrode

Claims (3)

[Claims] 1. A sealant for filling a desired liquid into a gap between a pair of substrates facing each other and sealing the same, wherein the sealant contains at least a resin component and light-shielding fine particles. 2. The sealant according to claim 1, wherein the light-shielding fine particles are at least one of carbon black and resin-coated carbon black. 3. A liquid crystal display device comprising: a color filter substrate and a counter electrode substrate which face each other via a sealing member; and a liquid crystal layer sealed between the two substrates. The color filter substrate comprises: a transparent substrate; A black matrix formed in a predetermined pattern in a display area on the transparent substrate and a colored layer having a plurality of colors, and at least a black matrix formed in a frame portion located outside the display area, wherein the sealing member is A liquid crystal display device, wherein the sealant according to claim 1 or 2 is disposed so as to contact a black matrix located at the frame portion.