JPH11109121A - Color filter base and its manufacture, and liquid crystal element using this base - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable color filter base having no color shading. SOLUTION: A metallic black matrix 2 is formed on a support base 1, and an ink receiving layer 3 consisting of a photosensitive resin composition hardenable by irradiation and thermal treatment is formed thereon. After the ink receiving layer 3 is pattern-exposed by use of a photomask 4, the black matrix 2 is heated by high frequency induction heating, and only a non-colored part 5 which is the exposed part is heated to perform a hardening reaction, and a colored ink 8 is imparted to a non-exposed part 6 from an ink jet head 7 to color it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter substrate of a color liquid crystal display used for a color television, a personal computer, a portable information terminal and the like, and a method of manufacturing the same, and more particularly, to a color filter substrate utilizing an ink jet recording technique. And a color filter substrate obtained by the method, and a liquid crystal element formed using the substrate.

[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, cost reduction is necessary for further popularization, and in particular, there is an increasing demand for cost reduction of color filters 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 which satisfies all the required characteristics. The respective methods will be described below.

The first method most frequently used is a dyeing method. In the dyeing method, first, a water-soluble polymer material that is a material for dyeing is formed on a glass substrate, and is patterned into a desired shape by a photolithography process.
The obtained pattern is immersed in a dyeing bath to obtain a colored pattern. By repeating this three times, R (red),
G (green) and B (blue) color filters are obtained.

[0005] A second method is a pigment dispersion method, which is recently replacing the dyeing method. In this method, first, a photosensitive resin layer in which a pigment is dispersed is formed on a substrate, and a monochromatic pattern is obtained by patterning the photosensitive resin layer. This process is repeated three times to form R, G, B color filters.

A third method is an electrodeposition method. In this method, a transparent electrode is first patterned on a substrate, and a pigment,
The first color is electrodeposited by dipping in an electrodeposition coating solution containing a resin, an electrolytic solution or the like. This process is repeated three times to form R, G, B color filters, and finally firing.

A fourth method is to disperse a pigment in a thermosetting resin and repeat printing three times to obtain R,
After separately applying G and B, the resin is thermally cured to form a colored layer. In any method, a protective layer is generally formed on the colored layer.

[0008] These methods have in common that R,
The same process needs to be repeated three times to form the three color filters of G and B, which increases the cost.
In addition, there is a problem that the yield decreases as the number of steps increases. Furthermore, in the electrodeposition method, since the pattern shape that can be formed is limited, the current technology cannot be applied to an active matrix type liquid crystal element using a TFT. In the printing method, a fine pitch pattern cannot be formed due to poor resolution.

In order to compensate for these drawbacks, a method of manufacturing a color filter using an ink jet system has been proposed. For example, an ink receiving layer made of a photosensitive resin composition curable by light irradiation or light irradiation and heat treatment is formed on a substrate, and the ink receiving layer is subjected to pattern exposure to form a non-colored portion. A method of applying a colored ink to an unexposed portion by an ink jet method, coloring a predetermined pattern, and then curing the entire ink receiving layer.

According to the above-mentioned ink jet method, it is possible to provide a color filter which satisfies the heat resistance, solvent resistance, resolution and the like required by the conventional method, and which can reduce the number of steps and is inexpensive.

[0011]

However, the following problems may occur in a method of manufacturing a color filter using an ink jet system. (1) Color density unevenness in the pixel (2) Dye aggregation due to insufficient ink permeability in the pixel (3) In-plane color unevenness due to heating variation in the display area This is considered to be due to a decrease in ink absorption capacity and in-plane variation.

An object of the present invention is to solve the above problems and to provide a highly reliable color filter substrate free from color unevenness at low cost.

[0013]

The invention according to claims 1 to 10 is a process for forming an ink receiving layer on a supporting substrate by using a photosensitive resin composition curable by light irradiation and heat treatment;
A step of pattern-exposing the ink receiving layer to form a non-colored part, a step of heating only the non-colored part, and a step of applying a colored ink to an unexposed part of the ink receiving layer by an ink-jet method and coloring. And heating the entire ink receiving layer or curing by heating and light irradiation.

Further, the invention of claims 11 and 12 is a color filter substrate characterized by being manufactured by the above-mentioned manufacturing method, and the invention of claim 13 is characterized by being constituted by using the color filter substrate. Is a liquid crystal element.

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, when the ink receiving layer is formed of a photosensitive resin composition which is cured by light irradiation and heat treatment, a step of forming a non-colored portion is performed. In, since the unexposed portion in the pattern exposure was also uniformly heat-treated, a slight curing reaction also proceeds in the unexposed portion, the permeability of the colored ink,
It was presumed that the coloring property was reduced. Therefore, by heating only the exposed portion (non-colored portion) as in the present invention, a decrease in ink permeability and coloring property in the unexposed portion is prevented, and color unevenness in the colored portion is eliminated. In particular, in the present invention, as a means for heating only the exposed portion, by using a black matrix usually formed corresponding to the non-colored portion, there is no need to add a new member, and the current manufacturing process Can be applied as is.

[0016]

FIG. 1 shows the steps of one embodiment of the manufacturing method of the present invention. (A) to (g) of FIG.
It is a section schematic diagram corresponding to ag.

Step-a A black matrix 2 is formed on a support substrate 1. In the present invention, the means for heating only the non-colored portion of the ink receiving layer described below is not particularly limited, but a heat energy generating member is formed on the upper or lower layer of the ink receiving layer,
Means for generating heat from the member is preferable, and it is preferable to use an ordinary black matrix as the heat energy generating member in order to avoid an increase in the number of manufacturing steps and members.

In the present invention, a glass substrate is usually used as the support substrate 1. However, a plastic or the like can be used as long as it has necessary characteristics such as transparency and mechanical strength as a color filter. In the case of forming a reflection type liquid crystal element, a non-translucent substrate on which a reflection member or the like is formed may be used, but is selected within a range that does not interfere with a heating step-d described later.

In the present invention, when the black matrix 2 is used as a heat energy generating member, its material is selected according to the heat generation mechanism. For example, in the present invention, a heat generation method by absorbing light energy or a high-frequency induction heating is preferably used. In the former case, the black matrix 2 is formed using a photosensitive resin composition or metal having absorption at a specific wavelength in the visible and infrared regions other than ultraviolet, and has a low ultraviolet intensity such as a deuterium lamp or a halogen lamp. The black matrix 2 is heated by irradiation of a lamp or the like. In the latter case, the black matrix 2 is made of a magnetic material such as chromium, nickel, cobalt,
A metal oxide such as a metal such as iron or a ferrite, or a resin composition in which magnetic particles are contained in an acrylic resin or a polyimide resin is applied, and electromagnetic energy is applied by high-frequency induction heating to generate heat. still,
When a resin is used, it is colored by including a black pigment or the like in order to have a light-shielding property.

The high-frequency induction heating refers to a phenomenon in which a metal or a magnetic substance instantaneously generates thermal energy due to the action of Joule heat due to hysteresis loss and eddy current in a high-frequency magnetic field. Joule heat due to electric current is expressed as follows.

Hysteresis loss (W) = 1.6 · n · f ·
B _m · V n: coefficient, f: frequency (Hz), B _m : maximum magnetic flux density (wb / m ² ), V: volume Joule heat = (・) · K · N ² · I ² · (P・ Μ ・
f) K: ratio constant, N: number of coil turns, I: coil current, P: specific resistance (μΩ · cm), μ: effective magnetic permeability

As described above, when a heat energy generating portion formed of a material containing at least a magnetic material is placed in a high-frequency magnetic field, the magnetic material portion constituting the heat energy generating portion is affected by hysteresis loss and Joule heat due to eddy current. Heat energy is generated, and it is possible to heat only the periphery of this portion. As a further advantage, the generation of thermal energy by high-frequency induction occurs in a very short time, so that the production time can be significantly reduced. In addition, since the amount of generated energy can be adjusted by adjusting the number of coil turns N, the coil current I, and the frequency f, the heating temperature can be controlled.

When the heat energy generating member is provided separately from the black matrix 2, the member may be formed by using the materials listed as the material of the black matrix 2.

The thickness of the black matrix 2 is usually 0.1 to 0.5 μm when formed of metal or the like, and 0.5 μm or more when formed of resin.

Step-b The ink receiving layer 3 is formed. The ink receiving layer 3 is formed of a photosensitive resin composition curable by light irradiation and heat treatment. Specifically, a photoinitiator (crosslinking agent) is appropriately added to an acrylic resin, an epoxy resin, an amide resin, a phenol resin, a polystyrene resin, or the like. As the photoinitiator, a cationic initiator is suitably used.
Furthermore, a photoacid generator such as an onium salt can be used in combination.

The ink receiving layer is formed by spin coating,
Coating methods such as roll coating, bar coating, spray coating, and dip coating can be used. The thickness is about 0.3 to 3.0 μm when a liquid crystal element is formed.

Step-c The non-colored portion 5 and the unexposed portion 6 are formed by pattern exposure of the ink receiving layer 3 using the photomask 4. At this time, by making the opening of the photomask 4 narrower than the width of the black matrix 2, it is possible to prevent white spots at the ends of the filter.

Step-d Heat is applied to the black matrix 2 to generate heat, and only the non-colored portions 5 are heated.

Step-e The colored ink 8 is applied to a predetermined unexposed portion 6 by the ink jet head 7 and colored. As the coloring ink, both dye-based and pigment-based inks can be used, and both liquid inks and solid inks can be used.However, when an aqueous ink is used, a resin composition having high water absorption in the ink receiving layer is used. It is preferable to use In addition, as the ink jet method, 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, and the coloring area and the coloring pattern can be set arbitrarily. it can.

Step-f The entire ink receiving layer including the colored portion 9 is heated and irradiated with light to cure the entire ink receiving layer.

Step-g A protective layer 10 is formed if necessary. As the protective layer 10, a photo-curing type, a thermo-setting type or a combination of light and heat type resin material, or an inorganic film formed by vapor deposition, sputtering, or the like can be used, and the transparency of the color filter is not impaired. Further, any material can be used as long as it can withstand the subsequent formation process of ITO, an alignment film, and the like.

FIG. 2 is a schematic cross-sectional view of one embodiment of a TFT color liquid crystal device incorporating the color filter substrate obtained in the above steps. In FIG. 2, 12 is a common electrode, 1
3 is an alignment film, 14 is a liquid crystal compound, 21 is a counter substrate, 22
Is a pixel electrode, and 23 is an alignment film.

A color liquid crystal element is generally formed by combining a color filter substrate and a counter substrate 21 and enclosing a liquid crystal compound 14. TFTs (not shown) and transparent pixel electrodes 22 are formed in a matrix inside one substrate 21 of the liquid crystal element. Also, on the inside of the other substrate 1, R,
A colored portion 9 of a color filter is provided so that G and B are arranged, and a transparent common electrode 12 is formed on one surface thereof. The black matrix 2 is usually formed on the color filter substrate side. However, in a BM-on-array type liquid crystal element, when a heat energy generating member is separately formed, it is formed on the opposite TFT substrate side. Further, alignment films 13 and 23 are formed in the planes of both substrates, and by subjecting them to rubbing treatment, liquid crystal molecules can be aligned in a certain direction. These substrates are opposed to each other via a spacer (not shown), are adhered by a sealing material (not shown), and a liquid crystal compound 14
Is filled.

In the liquid crystal element, a polarizing plate is bonded to the outside of each substrate, and a backlight in which a fluorescent lamp and a scattering plate are combined is generally used. A liquid crystal compound is used to change the transmittance of the backlight. Display is performed by functioning as a shutter.

In the above embodiment, the TFT color liquid crystal element has been described, but the present invention is not limited to this, and is preferably applied to other driving type liquid crystal elements such as a simple matrix type.

Further, in the liquid crystal element of the present invention, as long as the liquid crystal element is constituted by using the color filter substrate of the present invention, the conventional technique can be used as it is for other members. Therefore, as the liquid crystal compound, a TN liquid crystal, a ferroelectric liquid crystal, or the like generally used can be preferably used.

[0037]

【Example】

Example 1 A photosensitive resin composition having the following composition was spin-coated on a glass substrate having a black matrix produced by laminating Cr and CrO ₂ ,
Prebaking was performed for 0 minutes to form an ink receiving layer having a thickness of 1 μm.

Photosensitive resin composition: Terpolymer of N-methylolacrylamide, methyl methacrylate and hydroxyethyl methacrylate
10 parts by weight triphenylsulfonium trifluoromethylsulfonate (“TPS-105” manufactured by Midori Kagaku Co., Ltd.)
2 parts by weight

Next, the above-mentioned ink receiving layer was subjected to pattern exposure by deep-UV through a photomask having an opening smaller than the width of the black matrix.

Next, an electromagnetic induction coil was installed on the bottom surface of the glass substrate, and high-frequency induction heating (f = 350 kHz) was performed to generate heat in the black matrix and heat the exposed portion to perform a curing reaction.

Further, a dye ink is applied to the unexposed portion of the ink receiving layer by an ink jet head to form R, G, B
Was dried at 90 ° C. for 5 minutes and then heat-treated at 230 ° C. for 1 hour to cure the entire ink receiving layer.

When the color filter substrate for a liquid crystal element manufactured as described above was observed with an optical microscope, the color density unevenness in the pixel, the aggregation of the dye due to insufficient ink permeability in the pixel, and the Obstacles such as in-plane color unevenness due to heating variations were not observed.

Example 2 A color filter substrate was manufactured in the same manner as in Example 1 except that the black matrix was formed of Ni. Also for this color filter substrate,
As in Example 1, no problem was observed.

Example 3 A black matrix was formed by using a composition in which metal Ni fine particles were dispersed in a black resist (“V-259BK” manufactured by Nippon Steel Chemical Co., Ltd.).
A color filter substrate was manufactured in the same manner as in Example 1.
This color filter substrate is also similar to the first embodiment.
No problems were found.

Example 4 A color filter was produced in the same manner as in Example 1 except that a black matrix was heated by irradiating a halogen lamp for 10 minutes from the glass substrate side, and a curing reaction was performed by heating an exposed portion. A substrate was prepared. No problem was observed with this color filter substrate as in Example 1.

Example 5 A color filter substrate was manufactured in the same manner as in Example 4, except that the exposed portion was heated using a halogen lamp to perform a curing reaction. No problem was observed with this color filter substrate as in Example 2.

Example 6 A color filter substrate was manufactured in the same manner as in Example 3, except that the exposed portion was heated using a halogen lamp to perform a curing reaction. As with Example 3, no problem was observed with this color filter substrate.

[0048]

According to the present invention, there are no problems such as uneven coloring density in a pixel, agglomeration of dye due to insufficient ink permeability in a pixel, and in-plane color unevenness due to uneven heating in a display area. A color filter substrate with high quality can be obtained at low cost, and the cost of the liquid crystal element can be reduced. In particular, in the present invention, when a black matrix is used as a thermal energy generating member, the present invention can be carried out without adding a new member, so that an increase in manufacturing cost can be avoided.

[Brief description of the drawings]

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

FIG. 2 is a schematic cross-sectional view of one embodiment of the color liquid crystal element of the present invention using the color filter substrate of the present invention.

[Explanation of symbols]

 Reference Signs List 1 support substrate 2 black matrix 3 ink receiving layer 4 photomask 5 uncolored part 6 unexposed part 7 inkjet head 8 colored ink 9 colored part 10 protective layer 12 common electrode 13 alignment film 14 liquid crystal compound 21 counter substrate 22 pixel electrode 23 alignment film

Claims (13)

[Claims] 1. A step of forming an ink receiving layer on a supporting substrate using a photosensitive resin composition curable by light irradiation and heat treatment, and a step of pattern-exposing the ink receiving layer to form a non-colored portion. Heating the non-colored portion only,
A color filter comprising at least a step of applying a colored ink to an unexposed portion of the ink receiving layer by an ink jet method to color the ink receiving layer, and a step of heating or curing the entire ink receiving layer by heating and light irradiation. Substrate manufacturing method. 2. A color according to claim 1, wherein said means for heating the non-colored portion applies energy to a heat energy generating member provided in a region corresponding to the non-colored portion above or below the ink receiving layer to generate heat. Manufacturing method of filter substrate. 3. The method for manufacturing a color filter substrate according to claim 2, wherein said heat energy generating member generates heat by applying light energy. 4. The method for manufacturing a color filter substrate according to claim 3, wherein said heat energy generating member is made of a resin composition which generates heat when irradiated with light having a specific wavelength. 5. The method according to claim 3, wherein the heat energy generating member is made of a metal. 6. The method according to claim 2, wherein the heat energy generating member generates heat by applying electromagnetic energy. 7. The method for manufacturing a color filter substrate according to claim 6, wherein said thermal energy generating member is made of an inorganic material having magnetism. 8. The method for manufacturing a color filter substrate according to claim 6, wherein said thermal energy generating member is made of a resin composition containing magnetic particles. 9. The method for manufacturing a color filter substrate according to claim 8, wherein the resin composition constituting the thermal energy generating member is made of an acrylic resin or a polyimide resin. 10. The method for manufacturing a color filter substrate according to claim 2, wherein said thermal energy generating member is a black matrix. 11. A color filter substrate having a color filter on a support substrate, wherein the color filter substrate is manufactured by the manufacturing method according to any one of claims 1 to 10. 12. The color filter substrate according to claim 11, further comprising a protective layer on the color filter. 13. A liquid crystal sandwiched between a pair of substrates,
A liquid crystal device, wherein one of the substrates is formed using the color filter substrate according to claim 11.