JP2001166122A - Color filter, method for producing same and liquid crystal device using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a color filter which is not ruggedly distorted by heat treatment in a liquid crystal display producing step by an ink jet system. SOLUTION: An ink acceptor layer 3 comprising a resin composition to which ultrafine particles having <=120 nm average particle diameter of primary particles have been added is formed on a transparent substrate 1 and patternwise exposed and ink 8 is imparted from an ink jet head 7 to parts 6 to be colored to form colored parts 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device for color display used in a color television, a personal computer, a pachinko game machine, and the like, a color filter as a constituent member of the liquid crystal device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, the development of personal computers,
In particular, with the development of portable personal computers, the demand for liquid crystal displays, especially color liquid crystal displays, tends to increase. However, for further widespread use, it is necessary to reduce the cost of the liquid crystal display. In particular, there is an increasing demand for reducing the cost of a color filter having a high specific gravity. Conventionally, various methods have been tried to satisfy the above requirements while satisfying the required characteristics of the color filter, but no method has yet been established that satisfies all the required characteristics. The respective methods will be described below.

The first method is a pigment dispersion method. In this method, a photosensitive resin layer in which a pigment is dispersed is formed on a transparent substrate, and a monochromatic pattern is obtained by patterning the photosensitive resin layer. By repeating this step three more times, R
(Red), G (green), and B (blue) colored layers are formed.

[0004] The second method is a dyeing method. In the dyeing method, a water-soluble polymer material, which is a material for dyeing, is applied on a transparent substrate, and is patterned into a desired shape by a photolithography process. Get a pattern. By repeating this three times, three colored layers of R, G and B are formed.

A third method is an electrodeposition method. In this method, a transparent electrode is patterned on a transparent substrate, immersed in an electrodeposition coating solution containing a pigment, a resin, an electrolytic solution, etc., to form a first electrode.
Electrodeposit the color. This process is repeated three times and finally baked to form R, G, and B colored layers.

As a fourth method, there is a printing method. This method is a method in which a pigment is dispersed in a thermosetting resin, R, G, and B are separately applied by repeating printing three times, and then the resin is thermoset to form a colored layer.

In any of the above methods, a protective layer is generally formed on the colored layer. Also, these methods have in common that the same process needs to be repeated three times to color the three colors R, G, and B, which increases the cost. There is also a problem that the yield decreases as the number of steps increases. Further, in the electrodeposition method, since the pattern shape that can be formed is limited, it is difficult to apply the current technology to an active matrix type liquid crystal element using a TFT (thin film transistor). Further, the printing method has poor resolution and smoothness, so that it is difficult to form a fine pitch pattern.

In order to make up for these drawbacks, Japanese Patent Laid-Open Publication No.
JP-A-5205, JP-A-63-235901 and JP-A-1-217320 disclose a method of manufacturing a color filter using an ink jet method. In this method, ink containing three colorants of R, G, and B is ejected onto a transparent substrate by an inkjet method, and each ink is dried to form a colored portion. According to this method, it is possible to form each of the R, G, and B colored portions at one time, and it is possible to greatly simplify the manufacturing process and achieve a significant cost reduction effect.

[0009]

In the above-described color filter using the ink jet method, in the heat treatment process such as baking of the alignment film during the production of the liquid crystal element, the color filter has irregularities due to the stress generated due to the difference in the thermal expansion coefficient between the layers. In some cases, shape-like distortion was generated and the smoothness was impaired.

An object of the present invention is to solve the above problems, to provide a color filter which does not cause distortion in a liquid crystal element production process, and to provide a good liquid crystal element with good yield at low cost using the color filter. .

[0011]

The color filter of the present invention comprises a transparent substrate having a plurality of colored portions and a colored layer comprising a resin composition containing ultrafine particles having an average primary particle size of 120 nm or less. It is characterized by having.

According to the present invention, there is provided a light-shielding layer having a plurality of openings on a transparent substrate, a colored portion being disposed in each opening, a non-colored portion between adjacent colored portions, ultrafine particles, That the average particle diameter of the primary particles is 100 nm or less.

[0013] The method for producing a color filter of the present invention is a method for producing a color filter having a colored layer composed of a resin composition layer having a plurality of colored portions on a transparent substrate. Average primary particle size is 120nm
An ink receiving layer made of a resin composition containing the following ultrafine particles is formed, and ink is applied to the ink receiving layer by an inkjet method to form a colored portion.

In the production method of the present invention, the ink-receiving layer is formed of a photosensitive resin composition, and is subjected to pattern exposure to form a portion to be colored having an ink-receiving ability, and a portion having a lower ink-receiving ability than the portion to be colored. It is preferable to form a non-colored portion, form a colored portion by applying ink to a portion to be colored, and form a light-shielding layer on a transparent substrate, and form a non-colored portion on the light-shielding layer. It is included as an embodiment.

Further, the present invention provides a liquid crystal element characterized in that a liquid crystal is held between a pair of substrates, and one of the substrates is formed using the color filter of the present invention. is there.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a color filter of the present invention is characterized in that a colored portion is formed by applying ink by an ink jet method to an ink receiving layer made of a resin composition containing ultrafine particles, Preferably, the ink receiving layer is formed of a photosensitive resin composition, and is subjected to pattern exposure to form a colored portion and a non-colored portion to color the colored portion. Hereinafter, the present invention will be described by way of a preferred embodiment in which an ink receiving layer is formed with the above photosensitive resin composition.

FIG. 1 is a schematic view showing the steps of the embodiment. In FIG. 1, 1 is a transparent substrate, 2 is a black matrix, 3 is an ink receiving layer, 4 is a photomask, 5 is a non-colored portion, 6 is a portion to be colored, 7 is an inkjet head, 8 is ink, and 9 is a colored portion. Reference numeral 10 denotes a protective layer. 1A to 1D are schematic cross-sectional views corresponding to the following steps (a) to (d), respectively.

Step (a) A black matrix 2 is formed on a transparent substrate 1 as required. As the transparent substrate 1, glass is generally used, but plastics or the like may be used as long as they have necessary characteristics such as strength without impairing the transparency of the color filter. Further, the black matrix 2 may be a black stripe, and its film thickness is usually 0.1 to 0.5.
It is about 5 μm, and is obtained by forming a metal such as chromium on the transparent substrate 1 by sputtering or vapor deposition and patterning. Further, a black matrix may be formed by patterning with a black resin layer.

An ink receiving layer 3 is formed on the entire surface of the transparent substrate 1. The ink receiving layer 3 has an average primary particle diameter of 120.
It is a resin composition layer containing ultrafine particles of nm or less, and is preferably formed of a photosensitive resin composition whose ink receiving ability is changed by light irradiation or light irradiation and heat treatment.

As the resin material for forming the ink receiving layer 3, known materials can be used. For example, in consideration of heat resistance and the like, acrylic resins, epoxy resins, and imide resins are preferable. In consideration of the ink absorbency, those containing a cellulose-based water-soluble polymer such as hydroxypropylcellulose, hydroxyethylcellulose, methylcellulose, and carboxymethylcellulose are preferable. In addition, natural resins such as polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyurethane, carboxymethyl cellulose, polyester, and albumin, gelatin, casein, starch, cationized starch, gum arabic, and sodium alginate can be used. Is used in combination with a photoinitiator (crosslinking agent).

As the photoinitiator, dichromates, bisazide compounds, radical initiators, cationic initiators, anionic initiators and the like can be used. Further, these photoinitiators can be mixed. Alternatively, they can be used in combination with other sensitizers. Furthermore, a photoacid generator such as an onium salt can be used as a crosslinking agent. This embodiment shows an example in which a negative-type resin composition that loses (or reduces) ink receiving ability by light irradiation is used.

Further, the ink receiving layer 3 may contain various additives as necessary. Specific examples of additives include various surfactants, dye fixatives (waterproofing agents), defoamers, antioxidants, fluorescent brighteners, ultraviolet absorbers, viscosity adjusters, pH adjusters, Fungicides and plasticizers. These additives may be arbitrarily selected from conventionally known compounds according to the purpose.

The ultrafine particles to be added to the ink receiving layer 3 are formed by a step of thermally curing the ink receiving layer after coloring, a step of forming a protective layer 10 formed on the colored layer, a step of forming a transparent electrode, and a step of forming an alignment film. This is a member for relieving stress generated due to a difference in thermal expansion coefficient between layers generated in a process or the like, preventing unevenness of the color filter from occurring, and maintaining the smoothness of the color filter.

The ultrafine particles used in the present invention include organic ultrafine particles such as polyethylene wax and polytetrafluoroethylene, and inorganic ultrafine particles such as silicon oxide, zinc oxide and titanium oxide. It is preferable to use inorganic ultrafine particles because of the high-temperature heat treatment. In the present invention, it is necessary to maintain the transparency of the colored portion of the color filter by adding the ultrafine particles.
At 0 nm, it is necessary to use a colored part capable of maintaining transparency. When ultrafine particles that impair the transparency of the colored portion are used, the color characteristics of the color filter are greatly affected, and the brightness becomes poor. Therefore, as the ultrafine particles which do not impair the transparency in the above wavelength range, those having an average primary particle size of 120 nm or less are used. Preferably, the primary particles have an average particle size of 100 nm.
Use the following. This average primary particle diameter is a number average particle diameter and can be known by a method of directly measuring the size of primary particles from an electron micrograph.

In the present invention, the ink receiving layer 3
That the ultrafine particles added to the ink do not interfere with the ink receiving ability of the ink receiving layer 3 and that the adhesiveness between the transparent substrate 1 and the ink receiving layer 3 is not reduced. It is necessary to add an appropriate amount in consideration of eliminating the shape distortion, but the added amount is determined by the resin material of the ink receiving layer 3 used, the material of the protective layer 10, and the like. Although not particularly limited, it is preferably used in the range of 5 to 30% by weight.

As a method of forming the ink receiving layer 3, the above-mentioned ultrafine particles are added to the above resin material and the like, and the mixture is stirred until it becomes uniform. Then, spin coating, roll coating, bar coating,
It is applied and formed on the transparent substrate 1 by a method such as spray coating or dip coating, and is prebaked as necessary. The thickness of the ink receiving layer 3 is usually 0.3 to 3.0 μm.
It is about.

Step (b) The photoreceptor 4 is used to pattern-expose the ink receiving layer 3 to extinguish (or reduce) the ink receptivity of the exposed portions to form the non-colored portions 5. The non-colored portion 5 is formed at a position overlapping the black matrix 2, and in particular, is formed so that the non-colored portion 5 is narrower than the width of the black matrix 2 from the viewpoint of preventing white spots at the boundaries of the openings of the black matrix 2. Is preferred. In order to enhance the effect of preventing color mixing, it is also preferable to apply a component that causes the non-colored portion 5 to exhibit ink repellency to the ink receiving layer 3.

The area which has not been exposed in this step becomes the colored portion 6. When a positive-type resin composition in which the ink acceptability is expressed (or increased) by exposure is used, exposure may be performed in the reverse pattern.

Step (c) R, G, and B inks 8 are applied to the portion 6 to be colored along a predetermined coloring pattern by the ink jet head 7.

The ink 8 used in the present invention may be either a dye or a pigment.
Can be used as long as it is liquid at the time of discharge.

As the ink jet system used in the present invention, a bubble jet type using an electrothermal transducer as an energy generating element, a piezo jet type using a piezoelectric element, or the like can be used. Can be set arbitrarily.

Step (d) A necessary treatment such as heat treatment or light irradiation is performed to cure the entire ink receiving layer, thereby forming a colored layer including a non-colored portion 5 and a colored portion 9. Furthermore, if necessary, a protective layer 1
0 is formed to obtain the color filter of the present invention. Protective layer 1
As 0, a resin composition layer of a photo-curing type, a thermo-setting type, or a combination of heat and light, or an inorganic film formed by vapor deposition, sputtering, or the like can be used. In any case, any material can be used as long as it has transparency as a color filter and can withstand the subsequent ITO forming step, alignment film forming step, and the like.

Further, the color filter of the present invention may be provided by forming a transparent conductive film such as an ITO film as an electrode of a liquid crystal element on a colored layer or a protective layer.

Next, FIG. 2 is a schematic sectional view of an embodiment of the liquid crystal device of the present invention. The present embodiment is an example in which a TFT type color liquid crystal element is configured using the color filter of the present invention obtained by the process of FIG. In the figure, 13, 23
Is an alignment film, 12 is a common electrode, 21 is a counter substrate, 22 is a pixel electrode, and 24 is a liquid crystal. The same members as those in FIG.

In general, the color liquid crystal element is formed by combining the substrate 1 on the color filter side with the counter substrate 21 and forming
Is formed by encapsulating. TFTs (not shown) and pixel electrodes 22 are formed in a matrix inside one substrate 21 of the liquid crystal element. Further, inside the substrate 1 on the color filter side, at a position facing the pixel electrode 22,
A colored portion 9 of a color filter is formed so that R, G, and B are arranged, and a transparent common electrode 12 is formed thereon. The black matrix 2 is usually formed on the color filter side, but may be formed on the counter substrate 21 side such as a BM-on-array type liquid crystal element. Furthermore, alignment films 13 and 23 are formed in the plane of both substrates, and the liquid crystal molecules are arranged in a certain direction. These substrates are arranged to face each other via a spacer (not shown), are adhered to each other with a sealant (not shown), and a gap is filled with a liquid crystal 24.

In the case of the above-mentioned liquid crystal element, in the case of a transmissive type, a substrate 21 and a pixel electrode 22 are formed of a transparent material, a polarizing plate is bonded to the outside of each substrate, and a fluorescent lamp and a scattering plate are generally combined. The display is performed by using the backlight and using the liquid crystal compound as an optical shutter for changing the transmittance of the backlight. In the case of the reflection type, the substrate 21 or the pixel electrode 22 is formed of a material having a reflection function, or a reflection layer is provided on the substrate 21, and a polarizing plate is provided outside the transparent substrate 1. Display is performed by reflecting light incident from the filter side.

In the liquid crystal device of the present invention, as long as it is constituted by using the color filter of the present invention, it is needless to say that the conventional technique can be used as it is for the other members.

[0038]

EXAMPLES Example 1 A solution in which a photosensitive resin composition containing an acrylic copolymer having the following composition was uniformly dispersed by stirring was placed on an alkali-free glass whose surface was polished.
Spinner coating at 500 rpm for 60 seconds, 9
A baking treatment was performed at 0 ° C. for 20 minutes to form an ink receiving layer having a thickness of 1 μm.

[Composition of Photosensitive Resin Composition] Acrylic copolymer 10 parts by weight (ternary copolymer of methyl methacrylate / hydroxyethyl methacrylate / N-methylol acrylamide, monomer composition ratio = 2: 3: 5) Nylsulfonium hexafluoroantimonate 0.3 parts by weight Ethyl cellosolve 86.7 parts by weight Anhydrous silica 3 parts by weight ("R972" manufactured by Nippon Aerosil Co., Ltd., average particle size of primary particles: about 16 nm)

The above-mentioned ink receiving layer is subjected to pattern exposure through a photomask, and is heated on a hot plate at 120 ° C. for 1 hour.
A non-colored portion and a portion to be colored were formed in the ink receiving layer by performing a heat treatment for 5 minutes. R, G, and B inks having the following compositions were applied to the colored portions of the ink receiving layer in accordance with a predetermined coloring pattern and colored.

[Ink composition] Composition of R ink Red dye 4.5 parts by weight Ethylene glycol 20 parts by weight Isopropyl alcohol 5 parts by weight Water 70.5 parts by weight G ink composition Green dye 4.1 parts by weight Ethylene glycol 20 parts by weight Parts Isopropyl alcohol 5 parts by weight Water 70.9 parts by weight B ink composition Blue dye 5 parts by weight Ethylene glycol 20 parts by weight Isopropyl alcohol 5 parts by weight Water 70 parts by weight

Red dye: C.I. I. Acid Red 35 and C.I. I. Acid Yellow 23 11: 3 mixture Green dye: C.I. I. Acid Blue 9 and C.I. I. Acid Yellow 23 11: 3 mixture Blue dye: C.I. I. Acid Blue 9 and C.I. I. Acid Red 35 11: 3 mixture

After completion of the coloring step, baking was performed at 90 ° C. for 20 minutes and at 230 ° C. for 60 minutes to cure the entire ink receiving layer to form a colored portion. A two-component acrylic thermosetting resin material ("SS-7625" manufactured by Nippon Synthetic Rubber Co., Ltd.) is spin-coated thereon so as to have a thickness of 1 [mu] m, and is heat-treated in an oven at 240 [deg.] C. for 30 minutes. Was performed and cured to form a protective layer, thereby obtaining a color filter of the present invention. Next, an ITO film serving as an electrode of a liquid crystal element is formed on the protective layer by sputtering to a thickness of 15 nm.
The film was formed to have a thickness of 0 nm.

Using the obtained color filter as an advanced accelerated life tester ("EHS-210M" manufactured by Tabai Espec Corp.)
At 125 ° C. and a humidity of 85% for 12 hours, and then heat-treated on a hot plate at 250 ° C. for 20 minutes to obtain a surface step meter (“α step” manufactured by Tencor Corporation).
Was used to form a surface step. The surface step of the color filter of this example was 0.01 μm or less. Therefore,
Compared with Comparative Example 1 to be described later, the surface step is largely eliminated, and by incorporating ultrafine particles into the ink receiving layer, uneven distortion generated at the time of heat treatment is eliminated, thereby producing a color filter which does not impair the smoothness. It was confirmed that it was possible.

Comparative Example 1 A color filter including an ITO film was formed in the same manner as in Example 1 except that the ink receiving layer was formed of a photosensitive resin composition having the following composition.
When the surface step was measured in the same manner as in Example 1, the step of the color filter of this example was 0.3 μm.

[Composition of Photosensitive Resin Composition] Acrylic copolymer used in Example 1 10 parts by weight Triphenylsulfonium hexafluoroantimolate 0.3 parts by weight Ethyl cellosolve 89.7 parts by weight

[0047]

As described above, according to the present invention,
Without narrowing the selection range of the resin material constituting the ink receiving layer, it is possible to easily produce a color filter having high heat resistance and excellent smoothness by the inkjet method, and using the color filter, It is possible to provide a high liquid crystal element with good yield and at low cost.

[Brief description of the drawings]

FIG. 1 is a process chart of one embodiment of a method for manufacturing a color filter of the present invention.

FIG. 2 is a schematic sectional view of one embodiment of the liquid crystal element of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transparent substrate 2 black matrix 3 ink receiving layer 4 photomask 5 uncolored portion 6 colored portion 7 inkjet head 8 ink 9 colored portion 10 protective layer 12 common electrode 13 alignment film 21 counter substrate 22 pixel electrode 23 alignment film 24 alignment film

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Yoshihisa Yamashita, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akio Kashiwazaki 3- 30-2, Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Masafumi Hirose 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Mayumi Yokoyama 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. F Terms (reference) 2H048 BA02 BA11 BA57 BA60 BB02 BB14 BB28 BB44 2H091 FA02Y FA34Y FB02 FC01 LA12

Claims (8)

[Claims] 1. A color filter comprising: a transparent substrate; and a colored layer comprising a plurality of colored portions, and a colored layer made of a resin composition containing ultrafine particles having an average primary particle size of 120 nm or less. 2. A light-shielding layer having a plurality of openings on a transparent substrate, wherein each opening is provided with a colored portion.
The color filter described. 3. The color filter according to claim 1, having a non-colored portion between adjacent colored portions. 4. An ultrafine particle having an average primary particle diameter of 100
The color filter according to any one of claims 1 to 3, which has a thickness of at most nm. 5. A method for producing a color filter having a colored layer comprising a resin composition having a plurality of colored portions on a transparent substrate, wherein the primary particles have an average particle size of 1 on the transparent substrate.
A method for producing a color filter, comprising: forming an ink receiving layer comprising a resin composition layer containing ultrafine particles of 20 nm or less, and applying an ink to the ink receiving layer by an inkjet method to form a colored portion. 6. An ink receiving layer is formed of a photosensitive resin composition, and is subjected to pattern exposure to form a colored portion having ink receiving ability and a non-colored portion having lower ink receiving ability than the colored portion. The method for producing a color filter according to claim 5, wherein the colored portion is formed by applying ink to the colored portion. 7. The method for manufacturing a color filter according to claim 6, wherein a light shielding layer is formed on the transparent substrate, and a non-colored portion is formed on the light shielding layer. 8. A liquid crystal element comprising liquid crystal sandwiched between a pair of substrates, wherein one of the substrates is formed using the color filter according to claim 1.