JP2002040227A - Method for manufacturing color filter having high dielectric constant integrated with thin film transistor, color filter and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a color filter integrated with a thin film transistor in a small number of processes at a low cost such that formation of through holes or a transparent conductive film for driving a liquid crystal is not necessary and that voltage drop during driving the liquid crystal is suppressed. SOLUTION: The method for manufacturing a color filter integrated with a thin film transistor includes the following processes. A substrate for a liquid crystal display prepared by arranging thin film transistors and a light transmitting conductive film on a light transmitting substrate is disposed in a water-based electrodeposition liquid containing a coloring material, a light transmitting material having high dielectric constant and <=100 nm particle size, and an electrodepositing polymer material having crosslinking groups in the molecule and decreasing its solubility or dispersibility in the water-based liquid by the changes in the pH. In this state, thin film transistors corresponding to a specified conductive film are driven and a voltage is applied between the conductive film and the counter electrode so as to precipitate a color electrodeposition film having a high dielectric constant on the specified conductive film. The color filter has solvent resistance and a high dielectric constant. The liquid crystal display device uses this filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for forming a color filter used for various display devices such as a CCD camera and a liquid crystal display device and a color sensor, and relates to a method for manufacturing a colored layer and a black matrix. Specifically, the present invention relates to a method for manufacturing a new color filter for easily forming a colored layer and a black matrix at a high resolution.

[0002]

2. Description of the Related Art At present, color filters are produced by (1) a dyeing method, (2) a pigment dispersion method, (3) a printing method, (4) an ink jet method, (5) an electrodeposition method, and (6). A micelle electrolysis method and the like are known. Of these, (1)
Both the dyeing method and the (2) pigment dispersion method have a high degree of perfection of the technology, and are often used for color solid-state imaging devices (CCD).
It is necessary to perform patterning through a photolithography process, and there is a problem that the number of processes is large and the cost is high.
In contrast, (3) the printing method and (4) the ink-jet method do not require a photolithography step,
(3) The printing method is a method of printing and curing a thermosetting resin in which a pigment is dispersed, and is inferior in terms of resolution and film thickness uniformity. (4) The ink jet method is a method of forming a specific ink receiving layer, performing a hydrophilic / hydrophobic treatment, and then spraying ink on the hydrophilic portion to obtain a color filter layer. Furthermore, there is a high probability that color mixing will occur in the adjacent filter layers, and there is also a problem in terms of positional accuracy.

A color filter according to each of the above methods is generally formed on the ITO substrate side facing the TFT substrate. However, if a filter is formed at this position, it is necessary to align the TFT substrate and the color filter substrate after sealing the liquid crystal, and it is difficult to obtain high accuracy, which causes an increase in cost. I have.

(5) In the electrodeposition method, a high voltage of about 70 V is applied to a transparent electrode which has been patterned in advance in an electrolytic solution in which a pigment is dispersed in a water-soluble polymer to form an electrodeposition film. Electrodeposition is performed, and this is repeated three times to obtain an RGB color filter layer. In this method, it is necessary to previously pattern the transparent electrode by photolithography, and since this is used as an electrode for electrodeposition, the shape of the pattern is limited and cannot be used for TFT liquid crystal. In addition, if a color filter can be integrally formed by electrodeposition on the pixel electrode of the TFT liquid crystal substrate, it is not necessary to perform new patterning. However, in the conventional electrodeposition method, the electrodeposition voltage is high, and electrodeposition is performed on the transparent pixel electrode by an active matrix circuit. It is very difficult to cause the electrodeposition, and electrodeposition using the pixel electrode of the TFT has been impossible. Further, since the color filter layer becomes insulative, it cannot be used because the driving voltage is increased.

For example, Japanese Patent Application Laid-Open No. Hei 5-5874 discloses that
A technique for integrally forming a color filter on the TFT substrate side has been proposed. However, the electrodeposition film produced by the usual electrodeposition technique is insulative, and when a color filter is produced on a pixel electrode for driving a liquid crystal, the driving voltage of the liquid crystal increases and cannot be used. In addition, since an ordinary electrodeposited film contains impurities such as a surfactant, the color purity and transmittance are lowered, and it is necessary to protect the TFT circuit from an alkali metal contained in the film. Further, since it is impossible to electrodeposit directly on the pixel electrode using a normal TFT drive circuit, a TFT with a high breakdown voltage is required. For this reason, a method in which a color filter substrate and a TFT substrate are integrally formed and used has not been put to practical use.

(6) The micelle electrolysis method is a kind of electrodeposition method, but the voltage required for electrodeposition is low because the oxidation-reduction of ferrocene used as a deposition material is used. Can be integrally formed. However, the thin film formed by the micellar electrolysis method is mixed with impurities as ferrocene and surfactant, which are indispensable for the formation process, are taken in at the time of deposition, so that the transparency of the formed color filter deteriorates. The film has poor color purity and high resistance. In addition, the time required for electrodeposition requires several tens of minutes, resulting in a long time and poor production efficiency, and the ferrocene compound, which is an essential electrolytic component, is very expensive. Furthermore, since the formed thin film does not have solvent resistance, it is necessary to form a protective layer, which is problematic in terms of cost.

In general, a color filter cannot be used only with a color filter layer, and it is necessary to cover each color filter pixel with a black matrix. Usually, photolithography is used to form a black matrix, which is one of the major factors for increasing costs.

The present inventors have also applied for a color filter integrally provided on a thin film transistor (TFT) liquid crystal display substrate using an electrodeposition technique (Japanese Patent Application No. 11-304).
No. 910, Japanese Patent Application No. 2000-60145). This TFT
In an integrated color filter, since the electrodeposited colored film is insulative, it is necessary to provide a conductive film for driving liquid crystal on the colored film, and therefore, a through hole between the pixel electrode of the TFT and the conductive film is required. A hole must be formed,
There is a problem that the color filter manufacturing process becomes complicated. Some methods of directly driving without providing a through-hole have been proposed, but a method of conducting while maintaining color purity is difficult and has not been put to practical use. To solve this problem, the present inventors have completed and filed a method of forming a color filter colored film having conductivity on a TFT liquid crystal display substrate. (Japanese Patent Application 2000-67364
However, even in this method, the conductivity of the conductive color filter colored film leaves room for improvement, and in some cases, it is necessary to form a conductive film on the colored film and thus to form a through hole. there were.

Further, Japanese Patent Application Laid-Open No. 7-333595 discloses a color filter in which an adhesive layer containing a ferroelectric substance similar to a color filter layer containing a ferroelectric substance such as barium titanate is provided on a transfer substrate. A method of manufacturing a color filter in which a transfer substrate is positioned and mounted on a TFT liquid crystal display substrate and then a color filter layer is transferred together with an adhesive layer is described. By including a ferroelectric substance in the color filter layer and the adhesive layer, both methods are described. It is described that the voltage drop is suppressed by increasing the capacitance of the layer. However, this method requires a very complicated process of preparing a color filter transfer substrate in which a color filter layer and an adhesive layer are provided on a transfer substrate in advance, positioning the color filter transfer substrate with a TFT liquid crystal display substrate, and then transferring the same. In addition, the number of processes is large, and it is impossible to manufacture a high-resolution TFT-integrated color filter at low cost. This publication does not disclose at all how to form a color filter layer containing a ferroelectric substance on a transfer substrate.

Japanese Patent Application Laid-Open No. 2-60164 discloses that a simple matrix type liquid crystal display device comprises a color filter for an electrodepositable polymer, a dye, and an electrodeposition liquid containing high dielectric material particles. A color filter in which a colored film containing material particles is deposited and the electrical impedance of a color filter layer is reduced is described. By the way, in a liquid crystal display device, an alignment film such as polyimide is formed on a color filter layer, and the alignment film is usually formed by dissolving an alignment film resin in an organic solvent on the color filter layer. It is formed. However, in general, since the color filter layer does not have solvent resistance, when a resin solution is applied directly on the color filter layer, the color filter layer is dissolved by the organic solvent, so that a solution of the alignment film resin is applied. Usually, a protective film made of a polymer material which is thermally crosslinked and has improved solvent resistance is provided on the color filter layer before the alignment film is formed. However, since a protective film generally has a low dielectric constant, it is necessary to avoid forming a protective film on a color filter having a high dielectric constant as described above. Also,
When high dielectric constant material particles are contained in the color filter layer, there is a problem that the light transmittance generally decreases.

Therefore, the TFT-integrated color filter is manufactured by R.S. G. FIG. B. Considering the layer and the black matrix, high resolution, good color purity, high controllability, high light transmittance, little or no photolithography process, and even through holes and liquid crystal drive There is no need to form a conductive film at all, and a method of manufacturing a TFT-integrated color filter with higher yield and lower cost has not yet been realized.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to eliminate the need to form a through hole or a transparent conductive film for driving a liquid crystal, and to provide a liquid crystal driving device. It is an object of the present invention to provide a method for manufacturing a color filter integrated with a thin film transistor in which the voltage drop is suppressed at a low cost with a small number of steps.

[0013]

The above object can be attained by providing the following color filter manufacturing method and color filter. (1) A liquid crystal display substrate in which thin film transistors and a light-transmitting conductive film are arranged and formed on a light-transmitting substrate,
Water-based, high-permittivity material having a particle size of 100 nm or less and a water-based material containing an electrodepositable polymer material having a crosslinkable group in the molecule and having a reduced solubility or dispersibility in an aqueous liquid due to a change in pH. In the electrodeposition liquid, in a state where at least the conductive film of the liquid crystal display substrate is disposed so as to be in contact therewith, a thin film transistor corresponding to a predetermined conductive film is driven to apply a voltage between the conductive film and the counter electrode, A method for manufacturing a thin film transistor integrated color filter, comprising a step of depositing and forming a colored electrodeposition film having a high dielectric constant on the predetermined conductive film. (2) After performing a process of depositing and forming a colored electrodeposition film having a high dielectric constant on a predetermined conductive film, the above process is performed using an electrodeposition solution in which the coloring material is changed to a coloring material having another hue. The method for manufacturing a color filter integrated with a thin film transistor according to (1), wherein the method is repeated at least once. (3) The method for producing a color filter according to the above (1) or (2), wherein after the colored film is deposited and formed, the colored film is subjected to a heat treatment. (4) The relative permittivity of the colored electrodeposition film after the heat treatment is 4.0.
The method for manufacturing a color filter integrated with a thin film transistor according to any one of the above (1) to (3), characterized by the above.

(5) The color filter integrated with a thin film transistor according to any one of the above (1) to (4), wherein an insulating protective film is provided on the thin film transistor of the liquid crystal display substrate. Manufacturing method. (6) The method in which the insulating protective film is formed by irradiating a liquid crystal display substrate coated with a positive-type photoresist with light from a side where a light-transmissive electrode is not formed, and then etching. Characterized in (1) to (5) above
5. The method for manufacturing a color filter integrated with a thin film transistor according to any one of the above. (7) The above (1) to (6), wherein the positive photoresist is a positive black photoresist.
5. The method for manufacturing a color filter integrated with a thin film transistor according to any one of the above.

(8) The thin film transistor integrated type as described in any one of (1) to (6) above, further comprising forming a black matrix having an insulating property and a low dielectric constant after forming the color filter. Manufacturing method of color filter. (9) A low-reflection material is used as an electrode of the thin-film transistor, and the electrode has a function similar to that of a black matrix. The method for producing a color filter integrated with a thin film transistor according to the above item 2). (10) The method according to (9), wherein the electrode is provided with an insulating layer.

(11) The method of manufacturing a color filter integrated with a thin film transistor according to any one of (1) to (10), wherein the light-transmitting high dielectric constant material is an oxide semiconductor. (12) The method of manufacturing a color filter integrated with a thin film transistor according to any one of (1) to (11), wherein the oxide semiconductor is titanium oxide. (13) Any one of the above (1) to (12), wherein the particle size of the titanium oxide is 20 nm or less.
3. The method for producing a color filter integrated with a thin film transistor according to item 1.

(14) The electrodepositable polymer material is a copolymer of monomers each having a hydrophobic group, a hydrophilic group and a crosslinkable group, and the ratio of the number of hydrophobic groups to the total number of hydrophilic groups is 30%. The method for producing a color filter integrated with a thin film transistor according to any one of the above (1) to (13), which is 80% or less. (15) An ammonium salt that does not affect the characteristics of the thin film transistor is added to the electrodeposition liquid,
The method of manufacturing a color filter integrated with a thin film transistor according to any one of the above (1) to (13). (16) For the mixture 1 of the high dielectric constant material and the coloring material,
The method of manufacturing a color filter integrated with a thin film transistor according to any one of (1) to (15), wherein the electrodepositable polymer material is used at a ratio of 5.0 or less (volume ratio).

(17) The method according to any one of (1) to (16), wherein the applied voltage is set to 10 V or less. (18) The method for manufacturing a thin film transistor-integrated color filter according to any one of (1) to (17), wherein two or three layers of Cr are used as the electrodes of the thin film transistor. (19) The method according to any one of (1) to (18), wherein the internal resistance of the thin film transistor is 1 MΩ or less. (20) The method for manufacturing a color filter integrated with a thin film transistor according to any one of (1) to (19), wherein the thin film transistor is a polysilicon thin film transistor. (21) The method for producing a thin-film transistor integrated color filter according to any one of (1) to (20), wherein an organic alkali material is used when preparing the electrodeposition solution. (22) The method for producing a thin film transistor-integrated color filter according to any one of (1) to (21), wherein an ammonium salt is used when preparing the electrodeposition solution.

(23) A liquid crystal display substrate in which thin-film transistors and a light-transmitting conductive film are arranged and formed on a light-transmitting substrate. A color filter integrated with a thin film transistor, characterized in that it has a colored film and a black matrix having an insulating property and a low dielectric constant. (24) The color filter according to (23), a liquid crystal alignment film provided in contact with the color film of the color filter, and a counter substrate provided with a light-transmitting conductive film on the light-transmitting substrate. And a liquid crystal sealed between the liquid crystal alignment film and the counter substrate.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a color filter integrated with a thin film transistor according to the present invention has a crosslinkable group in a molecule as an electrodepositable polymer material, and its solubility or dispersibility in an aqueous liquid is changed by a change in pH. The electrodepositable polymer material (which may be referred to as a “crosslinkable polymer material” below) that decreases in size and has a particle size of 10 with a colorant and light transmittance.
A thin film transistor (hereinafter, referred to as “TFT”) and a liquid crystal display substrate on which a light-transmitting conductive film is formed are electrodeposited by using an electrodeposition liquid in which a high dielectric constant material having a thickness of 0 nm or less is dispersed. A colored electrodeposition film having a high dielectric constant and excellent solvent resistance is formed on the conductive film. Since the electrodeposited film produced by the ordinary electrodeposition technique is insulative, when a color filter is produced on a liquid crystal drive conductive film (pixel electrode), the drive voltage of the liquid crystal rises and cannot be used. . However, since the driving of the liquid crystal usually uses a pulse, if the dielectric constant of the color filter layer is high, the liquid crystal can be driven even through the color filter layer, but since the normal color filter layer has a low dielectric constant,
In this case, the conductive film cannot be used for driving the liquid crystal. However, according to the method of the present invention, a color filter layer having a high dielectric constant can be formed, and the method of the present invention comprises an electrodepositable polymer material, a high dielectric constant material, a pigment, and the like in an electrodeposition solution. Since the composition is substantially the same as the composition of the color filter layer to be produced, the dielectric constant can be arbitrarily controlled by adjusting the amount of a material having a light transmitting property and a high dielectric constant. In the color filter of the present invention, in order to use the conductive film for driving a liquid crystal, the relative permittivity of the colored film is preferably 4.0 or more.

In the colored electrodeposition film of the present invention, since the crosslinkable polymer material is crosslinked, acetone, isopropyl alcohol (IPA), n-methylpyrrolidone (NM
P) and other solvents used for forming the alignment film. The color electrodeposition film is dissolved even when the alignment film is formed using these solvents immediately above the color electrodeposition film. No deformation or deformation. Therefore, in the color filter of the present invention, it is possible to form an alignment film without providing a protective film. In general, the protective film has a low dielectric constant, and even if the colored electrodeposition film has a high dielectric constant, the dielectric constant is offset when the protective film is provided. However, in the present invention, since it is not necessary to form a protective film, it is possible to maintain a high dielectric constant of the colored electrodeposition film, and to use a conductive film (electrode) used in forming the colored electrodeposition film for liquid crystal driving. Can be used as an electrode.

Here, in the TFT liquid crystal display device using the TFT-integrated color filter of the present invention and the conventional color filter, a decrease in the effective voltage when a voltage is applied to the liquid crystal will be described. FIG. 2A is a schematic view showing a cross section of a conventional TFT liquid crystal display device provided with a color filter. In FIG. 2A, 100 is a TFT substrate, 102 is a polyimide alignment film, 104 is liquid crystal, and 106 is polyimide. Orientation film, 108 is a conductive film (ITO), 110 is a protective film,
Reference numeral 112 denotes a color filter layer, and 114 denotes a glass substrate. FIG. 2B is a schematic diagram showing a cross section of a liquid crystal display device provided with a TFT-integrated color filter of the present invention. In FIG. 2B, reference numeral 200 denotes a TFT substrate;
4 is a color filter layer, 206 is a polyimide alignment film,
Reference numeral 208 denotes a liquid crystal, 210 denotes a polyimide alignment film, 212 denotes a conductive film (ITO), and 214 denotes a glass substrate.
In the liquid crystal display device of the present invention, the alignment film is formed directly on the color filter layer.

Since the color filter layer manufactured by the manufacturing method of the present invention has a high dielectric constant, it is possible to suppress a decrease in effective voltage. Further, as shown in FIG. 2B, since the color filter layer of the present invention has solvent resistance, there is no need to provide a protective film thereon.

Here, the relative permittivity (ε
x), the film thickness (lx), and the area S of the one-pixel display section are set as follows: the area S of the one-pixel display section: 80 μm × 240 μm Liquid crystal: C _l = ε _l ε ₀ S / l _l , l = 6, l _l = 7 μm Alignment film (polyimide): ε _p = 4, C _p = ε _p ε ₀ S / l _p , lp
= 75 nm The color filter: ε _c, l _c polyimide / liquid crystal / polyimide _{layer: ε plp, l plp = 2lp} +
l _l The composite capacitance C _plp of polyimide / liquid crystal / polyimide layer is C _plp = C _p C _l / (2C _p + C _l ) = ε _l ε _p ε ₀ S / (2ε _p l _l + ε _l l _p ) _{... (1) ε plp = ε} l ε p l plp / (2ε p l l + ε l l p) Combined capacitance C _c of ... (2) color filter layer is given by _{C c = ε c ε 0 S} / l c ... (3).

When the voltage applied to the entire display section (between the upper and lower electrodes of ITO) is V, polyimide / liquid crystal
_Assuming that the voltages applied to the / polyimide layer and the color filter layer are V _plp and V _c , respectively, the ratio V _plp / V of the application voltage V _plp of the polyimide / liquid crystal / polyimide layer to the application voltage V of the entire display portion is V _plp / V = C _c / (2C _plp + C _c ) (4)

According to the equations (1) to (4), the applied voltage V of the polyimide / liquid crystal / polyimide layer relative to the applied voltage V of the entire display section when the relative permittivity ε _c and the film thickness l _c of the color filter are changed. FIG. 1 shows the result of _calculating the ratio V _plp / V of _plp . As shown in FIG. 1, it can be seen that there is a condition under which the reduction of the effective voltage can be suppressed within 10% when the relative dielectric constant of the color filter is increased and the film thickness is reduced. For example, when the color filter layer is formed with a thickness of 1.5 μm, a decrease in the effective voltage can be suppressed to within 10% by controlling the relative dielectric constant to 12 or more.

Therefore, the thickness of the color filter layer (colored electrodeposition film) of the present invention is set to 1.5 μm or less, preferably 1.0 μm or less, and the relative permittivity of the color filter layer is set to 5.0 or more, preferably 8 or more. 0.0 or more,
The decrease in the effective voltage can be suppressed to 15% or less.

We first included a colorant and p
A method for producing a color filter that forms a colored film by electrodeposition using an aqueous electrodeposition solution containing an electrodepositable polymer material whose solubility or dispersibility in an aqueous liquid decreases due to a change in H is completed ( JP-A-10-119414, JP-A-10-193768, JP-A-11-1
JP-A-89899, JP-A-11-105418, etc.), but all the electrodeposition techniques disclosed in these publications can be used for the electrodeposition method used in the present invention.

In the present invention, a TFT circuit is used to selectively apply a voltage to a predetermined conductive film, and a high dielectric constant color filter layer is selectively formed on the predetermined conductive film. It is characterized by. Therefore, the light-transmitting conductive film (pixel electrode) is used for both forming the color filter and driving the liquid crystal. Usually, a selective colored electrodeposition film is formed three times, and a color filter layer of three colors (red (R), green (G), and blue (B)) is integrally formed on the liquid crystal display substrate.

Here, from the viewpoint of protecting the TFT circuit at the time of forming the electrodeposition film, it is preferable to cover the TFT of the liquid crystal display substrate with an insulating protective film to block the electrodeposition liquid and the TFT. As a method of forming a protective film, for example, a positive type photoresist is applied on a liquid crystal display substrate, light is incident from a side where a light transmitting electrode is not formed, and then etching is performed. A method of exposing a portion other than the above, that is, a light-transmitting conductive film, and leaving a photoresist in a TFT portion is exemplified. According to this aspect, only the exposed light-transmitting conductive film portion comes into contact with the electrodeposition liquid, and a predetermined electrode is driven to form an electrodeposition film only on that portion. Will be protected by the resist. At this time, if a positive black photoresist material is used, that portion becomes a black matrix. Further, as a similar protection means, an insulating protection layer such as a silicon nitride film (SiNx) can be provided on the TFT. This insulating protective film is known as an etching stopper when manufacturing a TFT. It is also possible to form a colored electrodeposition film only on a predetermined portion by driving the exposed light transmissive electrode without providing the protective layer.

Preferably, a black matrix is formed above the TFT circuit of the TFT-integrated color filter. The optical density of the black matrix is usually required to be 2.5 or more, and it is necessary that light does not leak. In the present invention, the black matrix needs to be insulating (for both the color filter layer and the TFT) and have a low dielectric constant. As described above, the black matrix is formed by applying a black positive type photoresist on the entire surface of the liquid crystal display substrate before forming the color filter, and then irradiating light from the side where the TFT is not provided and then etching. One of the effective methods is to leave a black resist portion in the TFT portion where light is blocked. (In this case, the black resist layer also serves as an insulating protective film and a black matrix.) When the insulating protective layer is formed using a transparent photoresist, the resist is removed after forming the colored electrodeposition film. It is also possible to provide an insulating layer (insulated from both the color filter layer and the TFT) in that portion and form a black matrix on the insulating layer, for example, a black matrix using a pigment-dispersed black resist.

Further, after forming a color filter layer, a black negative photoresist is applied on the entire surface on which the film is formed, and then the substrate is irradiated with light from the side where the colored film is not formed. A black film is formed only in a region through which light passes through the substrate, and then the photoresist in the non-cured region is removed.

In addition, the black matrix may use a TFT electrode. Although the light blocking property of the gate electrode and the source electrode of the TFT circuit is originally high, if the gate electrode and the source electrode are formed of a low-reflection metal film, for example, a two-layer or three-layer Cr film, the color filter is formed. Since the electrode and the electrode line portion also serve as a black matrix, there is no need to separately provide a black matrix. In this case, the aperture ratio of the color filter can be maximized, and a very bright and high-definition liquid crystal display device can be formed. When the TFT electrode and the electrode line are used as a black matrix, when the TFT and the light-transmitting conductive film are arranged and formed, the electrode of the TFT is made of a low-reflection material, and silicon nitride is further added to the electrode. After providing an insulating protective layer such as a film, a transparent conductive film serving as a pixel electrode is formed, whereby the black matrix can be made insulating. In addition, a method of forming a metal-based black matrix by an ordinary method can be used as long as the insulating property with the color filter layer is maintained. In addition, known methods for forming a black matrix can be used without limitation.

Next, the electrodeposition liquid used in the present invention will be described. In the method for producing a color filter of the present invention, the electrodeposition material used for the electrodeposition liquid for forming an electrodeposition film has an ionic group, for example, a carboxyl group, and changes in solubility due to a change in the hydrogen ion concentration and precipitates. It is an electrodepositable polymer having properties, and the polymer needs to have a crosslinkable group in the molecule. The electrodepositable polymer has a function of dispersing the colorant and the transparent high dielectric constant material in the electrodeposition liquid. The electrodepositable polymer also serves as a matrix for the colored electrodeposition film, retains mechanical strength, and after being crosslinked by a crosslinkable group in the molecule, characteristics such as solvent resistance and heat resistance are improved. .

As the transparent high dielectric constant material used in the present invention, BaTiO ₃ , SrTiO ₃ , CaSnO ₃ ,
Barium titanate-based ferroelectrics such as BaSnO ₃ and BaZrO ₃ , lead zirconate titanate-based, TiO ₂ , MgT
iO ₃ There are a number of substances such as oxides of such. However, the barium titanate-based ferroelectric cannot be used alone because it has a large temperature coefficient instead of a very large dielectric constant. On the other hand, materials such as TiO ₂ and MgTiO ₃ are preferable because they have extremely small temperature dependence as used in capacitors for temperature compensation. In the present invention, in the high dielectric constant material, an oxide semiconductor, in particular, titanium oxide is preferably used. Further, as described above, in the electrodeposition method of the present invention, the composition of the electrodepositable polymer material, the high dielectric constant material, the pigment, and the like in the electrodeposition solution is substantially the same as the composition of the color filter layer to be manufactured. Therefore, the dielectric constant of the color filter layer can be arbitrarily controlled by adjusting the amount of a material having a light transmitting property and a high dielectric constant. The particle size of the high dielectric constant material is important. If the particle diameter of the high dielectric constant material is large, it is difficult to stably disperse the material in the electrodeposition solution, and the resulting colored electrodeposition film loses transparency. Therefore, the particle size is preferably 100 nm (0.1 μm) or less, preferably 50 nm or less, particularly preferably 20 nm or less.

As a method for dispersing light-transmitting fine particles having a high dielectric constant in the electrodeposition solution, a usual dispersion method can be used without any limitation. In order to obtain a colored electrodeposition film having a high dielectric constant, it is preferable that the electrodeposition liquid contains as much high dielectric constant material as possible. Therefore, the ratio of the electrodepositable polymer material to 5.0 or less (volume ratio) with respect to the mixture 1 of the high dielectric constant material and the colorant, and increasing the ratio of the light-transmitting high dielectric constant material. Is preferred. Further, the ratio of the high dielectric constant material to the colorant is desirably 1: 2 to 1:10 in terms of volume ratio from the viewpoint of transmittance and relative dielectric constant. Since a light-transmitting high dielectric constant material has an extremely heavy specific gravity as compared with a coloring material or an electrodepositable polymer, it is generally difficult to disperse the material in an aqueous system while maintaining the light transmitting property. However, as can be seen from the fact that titanium oxide is hydrophilic and used as a white pigment, dispersion in water is relatively easy, and an aqueous dispersion having sufficient transparency can be obtained. In particular, it has been found that when titanium oxide and a coloring agent pigment are used in combination, the dispersibility of titanium oxide is improved. The ratio (volume ratio) between titanium oxide and pigment is 1:
It is preferable to set the ratio to 2 to 1:10 in order to achieve a good balance of dispersibility and light transmittance.

Next, an electrodepositable polymer material having a crosslinkable group in the molecule and having a reduced solubility or dispersibility in an aqueous liquid due to a change in pH will be described. The electrodepositable polymer material has sufficient solubility or dispersibility in an aqueous liquid (including an aqueous liquid whose pH has been adjusted), and has an optical transparency. is necessary.
Examples of the crosslinkable group include an epoxy group, a blocked isocyanate group (including a group that can be converted into an isocyanate group), a cyclocarbonate group, and a melamine group. Also, p
In order to have a function of reducing solubility or dispersibility in an aqueous liquid due to a change in H, the molecule preferably has a hydrophilic group and a hydrophobic group in the molecule. As the hydrophilic group, a carboxyl group (anionic group), Amino group (cationic group)
It is preferable that an ionizable group (hereinafter, simply referred to as “ionized group”) is introduced. For example, in the case of a polymer material having a carboxyl group, when the pH is in an alkaline region, the carboxyl group is dissociated and dissolved in an aqueous liquid, and in an acidic region, the dissociation state disappears and the solubility is reduced to precipitate.

It is preferable that the electrodepositable polymer material has a hydrophobic group in addition to the ionized group. The presence of the hydrophobic group gives the polymer material a function of instantaneously depositing a film, in combination with the fact that the group dissociated by the ion loses ionicity due to the change in pH as described above. In addition, in the method of forming a color filter of the present invention described later, the hydrophobic group has a strong affinity for an organic pigment used as a coloring material and thus has a capability of adsorbing the organic pigment, and has a good pigment dispersing function for a polymer. Give. In addition, examples of the hydrophilic group include a hydroxy group and the like in addition to the ionized group.

The number of the hydrophobic groups in the polymer having a hydrophobic group and a hydrophilic group is preferably in the range of 30% to 80% of the total number of the hydrophilic groups and the hydrophobic groups. If the number of hydrophobic groups is less than 30% of the total number of hydrophilic groups and hydrophobic groups, the formed film is easily redissolved, and the water resistance and strength of the film may be insufficient. If it is larger than 80% of the total number of hydrophobic groups, the solubility of the polymer in the aqueous liquid becomes insufficient, so that the electrodeposition solution becomes turbid or a precipitate of the electrolytic material is generated.
Since the viscosity of the electrodeposition liquid tends to increase, it is desirable to be within the above range. The number of hydrophobic groups based on the total number of hydrophilic groups and hydrophobic groups is more preferably in the range of 55% to 70%. Those in this range have a particularly high electrodeposition deposition efficiency of the film,
A film can be formed at a low electrodeposition potential, and the liquid property of the electrodeposition liquid is stable.

Examples of the electrodepositable polymer material include those obtained by copolymerizing a polymerizable monomer having a crosslinkable group, a polymerizable monomer having a hydrophilic group, and a monomer having a hydrophobic group. Examples of the polymerizable monomer having a crosslinkable group include glycidyl (meth) acrylate,
(Meth) acrylic acid azide, methacrylic acid 2- (O-
[1'-Methylpropylideneamino] carboxyamino) ethyl (trade name: Karenz MO, manufactured by Showa Denko KK)
1-BN), 4-((meth) acryloyloxymethyl) ethylene carbonate, (meth) acryloylmelamine and the like. These crosslinkable monomers vary depending on the type of the monomer used, but generally comprise 1 to 20 mol% of the electrodepositable polymer compound. Further, as the polymerizable monomer containing a hydrophilic group, methacrylic acid, acrylic acid, hydroxyethyl methacrylate, acrylamide, maleic anhydride, fumaric acid, propiolic acid, itaconic acid, and the like, and derivatives thereof are used. It is not limited. Among them, methacrylic acid and acrylic acid are particularly useful hydrophilic monomers having high electrodeposition efficiency due to pH change. Further, a polymerizable monomer material containing a hydrophobic group, alkene, styrene, α-methylstyrene, α-ethylstyrene, methyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, ethyl acrylate, butyl acrylate, lauryl methacrylate, And the like and derivatives thereof are used, but are not limited thereto. In particular, styrene and α-methylstyrene are useful hydrophobic monomers that have a strong hydrophobicity and thus easily obtain hysteresis characteristics with respect to re-dissolution.
Acrylic acid or methacrylic acid as a hydrophilic group-containing monomer, styrene or α-methylstyrene as a hydrophobic group-containing monomer as the crosslinkable polymer material used in the color filter manufacturing method of the present invention, or a crosslinkable monomer as described above was used. Tertiary copolymers are preferably used.

The electrodepositable polymer material used in the production method of the present invention is a polymer material obtained by copolymerizing the above polymerizable monomers each containing a crosslinkable group, a hydrophilic group and a hydrophobic group in the above-mentioned ratio. However, the types of the hydrophilic groups and the hydrophobic groups are not limited to one type. The degree of polymerization is 6,000
From 25,000 is a polymer material for obtaining a good electrodeposition film. More preferably, the degree of polymerization is from 9,000 to 2
000 materials. When the degree of polymerization is lower than 6,000, it is easy to redissolve. When the degree of polymerization is higher than 25,000, the solubility in an aqueous liquid becomes insufficient, and the liquid becomes turbid or a precipitate is formed, which causes a problem.

When the electrodepositable polymer material has an anionic group such as a carboxyl group, the acid value of the electrodepositable polymer material is in the range of 60 to 300, and the electrodeposition property is good. Is obtained. In particular, the range of 90 to 195 is more preferable. If the acid value is less than 60, the solubility in the aqueous liquid becomes insufficient, the solid content concentration of the electrodeposition liquid cannot be increased to an appropriate value, the liquid becomes turbid, a precipitate is formed, and the liquid viscosity is lowered. Rises, causing problems.
When the acid value exceeds 300, the formed film is easily redissolved, so the above range is appropriate.

In addition, the above-mentioned electrodepositable polymer material undergoes a change in liquid properties that causes a supernatant to form a precipitate from a dissolved state or a dispersed state in accordance with a change in the pH value of the electrodeposition solution in which the electrodepositable polymer material is dissolved. It preferably occurs within pH range region 2. When the pH range is within 2 or less, an image can be instantaneously deposited even with a sharp pH change due to energization. Excellent effects such as reduction. Thus, a filter layer having high translucency and water resistance can be obtained. When the pH range is larger than 2, the printing speed for obtaining a sufficient image structure tends to decrease, and the image tends to lack water resistance. In order to obtain more preferable characteristics, the pH range is within 1 or less.

Further, the electrodeposition solution in which the electrodepositable polymer material is dissolved is characterized in that, in addition to the change in pH value, the state change which causes precipitation occurs sharply, and furthermore, it is hard to redissolve. It is preferable to have This characteristic is called a hysteresis characteristic. For example, in the case of an anionic electrodeposition material, precipitation occurs rapidly due to a decrease in pH, but even when the pH increases (for example, at the end of electrodeposition, that is, when voltage is applied, , Etc.) means that re-dissolution does not occur rapidly and the precipitation state is maintained for a certain period of time. On the other hand, those which do not show hysteresis characteristics have increased solubility even if the pH slightly increases, and the deposited film is easily redissolved.

The electrodepositable polymer material having the above properties can be obtained by appropriately adjusting the types of hydrophilic group and hydrophobic group, balance between hydrophilic group and hydrophobic group, acid value, molecular weight and the like.

Dyes and pigments are used as coloring materials to be added to the electrodeposition solution of the present invention. Dyes and pigments are
It is not necessary for the electrodeposition liquid to have the property of decreasing its solubility or dispersibility in response to a change in pH of the electrodeposition liquid. In this case, when a component other than the coloring material having the above properties, for example, an electrodepositable polymer material is aggregated and deposited to form a film, the film is taken into the film and colored. Liquid p
Examples of the dye whose solubility or dispersibility is reduced by changing H include ionic dyes. Further, an ionic dye and a pigment can be used in combination.
Examples of ionic dyes include triphenylmethanephthalide, phenosadine, phenothiazine, fluorescein, indolylphthalide, spiropyran, azaphthalide, diphenylmethane, chromenopyrazole, leuco auramine, azomethine, Rhodamine lactal type, naphtholactam type, triazene type, triazole azo type, thiazole azo type, azo type, oxazine type, thiazine type, benzothiazole azo type, quinone imine type dye, and hydrophilic having carboxyl group, amino group, or imino group And the like. For example, rose bengal and eosin, which are fluorescein dyes, are soluble in water at pH = 4 or higher, but become neutral and precipitate at pH lower than 4. Diazo Pro Jet Fast Yello
w2 is soluble in water above pH 6, but precipitates below that. As the pigment, known red, green, blue and other pigments can be used without any particular limitation. The smaller the pigment particle size, the better the hue reproducibility. When producing a color filter, from the viewpoint of transparency and dispersibility of the color filter layer, particularly, the average particle diameter of the pigment is 200 nm
(0.2 μm), preferably 100 nm (0.1 μm) or less. As the coloring material for a color filter, the present inventors have previously disclosed, as materials suitable for the photoelectric deposition method, Japanese Patent Application Nos. 9-268462 and 9-329.
The coloring material described in the specification proposed as 798 can also be used.

When two or more kinds of coloring materials are used, an arbitrary mixed color can be obtained, and it is possible to combine a dye and a pigment. Regarding the ionicity of the colorant when mixing two types of colorants to produce a mixed color, use a non-polar colorant or use a colorant of the same polarity to prevent the colorant from sedimentation or precipitation. It is generally used. However, certain types of dyes do not form a complex and coexist with ions.In this case, even when a basic solution and an acidic solution are mixed, precipitates can be suppressed, and the polarity of ions can be reduced. It can be used regardless of. In the present invention, an electrodeposition liquid in which a pigment is dispersed using a polymer material having an anionic group is preferably used for a color filter.

As the film-forming material contained in the electrodeposition solution of the present invention, any of the materials described above can be arbitrarily combined as long as the effect of forming a thin film is not impaired. A mixture of the same polarity molecules such as a mixture, or a mixture of different polarity molecules such as a mixture of an anionic molecule and a cationic molecule may be used.

Next, the conductivity of the electrodeposition liquid will be described. The conductivity is related to the electrodeposition speed, in other words, the amount of electrodeposition. The higher the conductivity, the thicker the electrodeposition film deposited for a certain period of time and saturates at about 20 mS / cm. Therefore,
If the conductivity is not sufficient with only the electrodepositable polymer material or the electrodepositable dye ion, the electrodeposition can be performed by adding ions that do not affect the electrodeposition, for example, NH ₄ ⁺ ions or Cl ⁻ ions. Speed can be controlled. Usually, the electrodeposition liquid increases the conductivity by adding a supporting salt. In electrochemistry,
Commonly used supporting salts include alkali metal salts such as NaCl and KCl, ammonium chloride, ammonium nitrate,
Tetraethylammonium perchlorate (Et ₄ NC
Tetraalkylammonium salts such as 10 ₄ ) are used. However, an alkali metal adversely affects the characteristics of a thin film transistor. Therefore, when a colored electrodeposition film is formed on a substrate provided with a thin film transistor, an electrodeposition solution containing the film cannot be used. Therefore, in the method of the present invention, NH 3
Ammonium salts such as ₄ Cl and NH ₄ NO ₃ , Et ₄ NCl
O ₄ , n-Bu ₄ NCLO ₄ , Et ₄ NBF ₄ , Et ₄ NB
r, it is preferable to use tetraalkylammonium salts such as n-Bu ₄ NBr. Such a compound, even if present in the electrodeposited film, does not adversely affect transistor characteristics.

The pH of the electrolytic solution naturally affects the formation of a thin film. For example, if a film is formed under conditions such that the solubility of the film-forming molecules is saturated before forming the thin film, it is difficult to redissolve after forming the thin film. However, the pH of the unsaturated solution
When the film is formed by the method described above, even if a thin film is formed, the film starts to be redissolved as soon as the irradiation of light is stopped. Therefore, since it is more desirable to form a thin film at the pH of a solution that saturates the solubility, it is necessary to adjust the electrolytic solution to a desired pH using an acid or an alkali. When a thin film is formed on a substrate provided with a thin film transistor (TFT), an alkali metal salt cannot be used for the same reason as described above. Therefore, in this case, an amine-based or ammonia-based organic alkali material is used. Tetramethyl hydroxide is widely used as an etching solution for a photoresist and has good compatibility with a thin film transistor, so that it can be particularly preferably used.

Next, a method for forming a color filter and a black matrix on a liquid crystal display substrate will be specifically described. As an example, a method for manufacturing a color filter using a black positive photoresist and provided with an insulating protective layer and a layer serving as a black matrix will be described. First, a liquid crystal display substrate in which a TFT element and a conductive film (pixel electrode) are formed on a transparent glass substrate 1 is manufactured by an ordinary method. FIG. 3 is a cross-sectional view of an example of a liquid crystal display substrate. In the figure, 1 is a glass substrate, 2 is a gate electrode, 3 is a source electrode, 4 is a conductive film (pixel electrode), 5 is a drain electrode, 6 is an etching stopper, 7 is n + a-Si, 8 is an insulating film, and 9 is a gate. The insulating films 10 and 10 indicate etching stoppers, respectively. FIG. 4A shows a structure in which an insulating and black film (insulating black matrix) is provided only in the TFT portion of the liquid crystal display substrate shown in FIG. In order to obtain this structure, a positive black photoresist 5 is applied to the entire surface of the liquid crystal display substrate (portion including the dotted line). Light is irradiated from the back of the glass substrate 1 (FIG. 4A).
(Indicated by arrows in the middle.) Then, when etching is performed, since the source electrode 2, gate electrode 3, and drain electrode of the TFT serve as a photomask, a positive black photoresist 5 remains on the TFT, which is an insulating black. Functions as a matrix. On the other hand, since light passes through the pixel electrode 4, the photoresist indicated by the broken line in FIG. 4A is etched to expose the conductive film (ITO pixel) electrode 4. FIG. 4B shows a structure in which the colored electrodeposition film 10 is formed in a region where the pixel electrode in FIG. 4A is exposed. The colored electrodeposition film is formed between the pixel electrode corresponding to the TFT circuit and the counter electrode (not shown) by driving the selected TFT circuit with at least the pixel electrode in contact with the electrodeposition liquid. It is formed by applying a voltage. This colored electrodeposition film 10 becomes a monochromatic color filter layer. At this time, the source electrode 3 and the drain electrode 5 are provided with a protective layer of black resist 5 on the surface and do not come into contact with the electrodeposition liquid. A colorant of any one of R, G, and B is used for the electrodeposition film, and the position of the driving circuit for forming the electrodeposition film is similarly changed for the other hues by changing the electrodeposition liquid. Is controlled, and a color filter layer is sequentially formed at a predetermined position, whereby a full-color color filter can be formed.
FIG. 5 is a front view showing the structure of a TFT-integrated color filter on which a colored film is formed as described above. The applied voltage is preferably 10 V or less in order to prevent the generation of bubbles, and particularly preferably 5 V or less.

It is preferable that the internal resistance of the TFT is low. Further, it is preferable that the TFT is a polysilicon thin film transistor from the viewpoint that the applied voltage can be reduced.

The color filter of the present invention is manufactured by the above-described manufacturing method, and includes a liquid crystal display substrate in which thin film transistors and a light transmitting conductive film are arranged and formed on a light transmitting substrate. On the conductive film of the above,
It has a solvent-resistant colored film having a dielectric constant of 4.5 or more, and has an insulating, low-dielectric constant black matrix,
The conductive film functions as a liquid crystal driving electrode. Since the color filter of the present invention has solvent resistance, it is possible to directly provide a liquid crystal alignment film without providing a protective film having a low dielectric constant thereon, and therefore, by utilizing the high dielectric constant of the color film of the color filter. In addition, the conductive film can function as an electrode for driving the liquid crystal.

Further, in the liquid crystal display device of the present invention, a color filter, a liquid crystal alignment film provided in contact with a colored film of the color filter, and a light-transmitting conductive film on a light-transmitting substrate are provided. And a liquid crystal sealed between the liquid crystal alignment film and the counter substrate, wherein a protective film is not provided between the liquid crystal alignment film and the liquid crystal. FIG. 2B illustrates a cross-sectional configuration of an example of the liquid crystal display device of the present invention.

According to the method of manufacturing a color filter of the present invention, a color filter film (colored film) having a high dielectric constant can be formed, so that a voltage drop when driving the liquid crystal is suppressed. Therefore, there is no need to form a contact hole or a transparent conductive film for driving the liquid crystal, and the conductive film (pixel electrode) can be used as an electrode for driving the liquid crystal, thus simplifying the structure. Further, it is not necessary to use photolithography, and the number of steps is small, and a color filter with high resolution and high controllability can be provided. Further, the present invention is a simple color filter manufacturing method which can cope with a fine and complicated pixel arrangement of a color filter pattern, can easily form a black matrix, and can be mass-produced.
In addition, since the colored film of the color filter of the present invention has solvent resistance, there is no need to form a protective film before forming an alignment film, which has the advantage of further reducing the number of steps. In addition, there is no need to align the color filter with the TFT substrate, and a high-precision liquid crystal display element having a large aperture ratio can be manufactured at low cost. Furthermore, TFT
By examining the color filter layer for non-adherence or erroneous adhesion of the substrate defect, it becomes possible to know whether there is a disconnection defect or a short-circuit defect in the TFT circuit. Further, since the liquid crystal display element of the present invention uses the color filter as described above, it is excellent in resolution and the like, and there is no need to perform complicated alignment in its assembly, so that it can be easily manufactured at low cost. .

[0056]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. (Example 1) <Preparation of liquid crystal display substrate> A thin film transistor (amorphous silicon TFT, internal resistance: 1M) was placed on a 0.7 mm thick non-alkali glass substrate (1737 glass manufactured by Corning Incorporated).
Ω) and a transparent conductive film (ITO). At this time, the gate electrode and the drain electrode of the TFT are formed of two layers of chromium, and after the formation of the color filter layer, an insulating layer of silicon nitride is provided so that the electrode and the power supply line part can also serve as a black matrix. When the pixel electrode was formed by using, ITO was formed so as to be extended so as to overlap with the power supply line, and a transparent region other than the pixel electrode region was used as a TFT substrate.

<Formation of red colored film> Styrene / acrylic acid / methacrylic acid 2- (O- [1′-methylpropylideneamino] carboxyamino) ethyl copolymer (molecular weight 13,000, hydrophobic group / (hydrophilic group + hydrophobic) Group) molar ratio 65%, acid value 15
0, 2- (O- [1'-methylpropylideneamino] carboxyamino) ethyl methacrylate content: 3.3 mol%; hereinafter, this crosslinkable polymer material is simply referred to as "crosslinkable polymer material". ) And a mixture of a pigment and a high dielectric constant material (a mixture of an azo red ultrafine particle pigment and titanium oxide ultrafine particles at a volume ratio of 1: 0.3. In the following, a mixture of a pigment and a high dielectric constant material is simply referred to as (A “pigment mixture”) was dispersed at a volume ratio of a crosslinkable polymer material / pigment mixture = 1/1, and a solid content concentration of 7% by weight (pH = 7.8, conductive At a rate of 8 mS / cm), the liquid crystal display substrate was arranged such that the conductive film was in contact therewith. As the electrodeposition apparatus, a three-electrode type apparatus generally used in electrochemistry was used.
Platinum black was used for the counter electrode. A working electrode of a potentiostat is connected to the source electrode, a voltage of 10 V is applied to the saturated calomel electrode, and a voltage is applied to a gate electrode of a predetermined TFT corresponding to a pixel electrode on which a red colored film is to be formed. The TFT circuit was driven so as to be applied, and a voltage was applied to a predetermined pixel electrode for one minute. As a result, a red colored film was formed on the pixel electrode. This was washed with pure water. <Formation of Green Colored Film> Except for changing the pigment to a phthalocyanine green-based ultrafine particle pigment, an electrodeposition solution was prepared in the same manner, and a green colored film was formed on a predetermined pixel electrode in the same manner. And washed. <Formation of Blue Colored Film> An electrodeposition solution was prepared in the same manner except that the pigment was changed to a phthalocyanine blue-based ultrafine particle pigment, and a blue colored film was formed on a predetermined pixel electrode in the same manner. And washed. <Baking> The liquid crystal display substrate with the colored film
Heating was performed at 0 ° C. for 30 minutes. As a result, a TFT-integrated color filter having a solvent-resistant colored film having a high dielectric constant (relative dielectric constant: 6.0) and having a TFT insulating electrode functioning as a black matrix was produced. When a liquid crystal display device is manufactured using this color filter, a protective film becomes unnecessary.

Example 2 <Preparation of Liquid Crystal Display Substrate> A thin film transistor (polysilicon TFT, internal resistance: 100K) was formed on a 0.7 mm thick non-alkali glass substrate (1737 glass manufactured by Corning Incorporated).
Ω) and a transparent conductive film (ITO). At this time, the gate electrode and the drain electrode of the TFT are formed of two layers of chromium, and after the formation of the color filter layer, an insulating layer of silicon nitride is provided so that the electrode and the power supply line part can also serve as a black matrix. When the pixel electrode was formed by using, ITO was formed so as to be extended so as to overlap with the power supply line, and a transparent region other than the pixel electrode region was used as a TFT substrate.

<Preparation of Color Filter> Red, green, and blue colored films were formed in the same manner as in Example 1, and then baked, so that the TFT insulating electrode functioned as a black matrix. A TFT-integrated color filter having a colored film formed thereon was produced.

Example 3 <Preparation of Liquid Crystal Display Substrate> A thin film transistor (polysilicon TFT, internal resistance: 100K) was placed on a 0.7 mm thick non-alkali glass substrate (1737 glass manufactured by Corning Incorporated).
Ω) and a transparent conductive film (ITO) pixel electrode to form a liquid crystal display substrate. <Formation of Black Matrix> A positive black resist was applied to this liquid crystal display substrate, and light was irradiated from the back surface of the substrate to etch only the light-irradiated area, thereby exposing the pixel electrodes. A black matrix was formed in a portion where light did not pass. This black matrix also functions as an insulating protective film for the TFT. <Preparation of Color Filter> A red, green, and blue colored film was formed in the same manner as in Example 1, and then baked to have a black matrix made of a black resist. Was formed to produce a TFT-integrated color filter.

Example 4 <Preparation of Liquid Crystal Display Substrate> A thin film transistor (amorphous silicon TFT, internal resistance: 1) was formed on a 0.7 mm-thick non-alkali glass substrate (1737 glass manufactured by Corning Incorporated).
(MΩ) and a transparent conductive film (ITO). <Formation of Insulating Protective Film> A positive-type photoresist was applied to this liquid crystal display substrate, and light was irradiated from the back surface of the substrate to etch only the light-irradiated area to expose the pixel electrode. The portion of the resist that does not transmit light functions as a protective coating that is insulative to the TFT. <Formation of Colored Film> Red, green, and blue colored films were formed in the same manner as in Example 1, and then baked. <Formation of black matrix> An ultraviolet curable resin containing carbon black is applied to the surface of the liquid crystal display substrate on which the color film is to be formed after the baking process, and the black matrix is applied only to the area where light is leaked by irradiating light from the back of the substrate. Was formed. As a result, a TFT having a black matrix made of black resin and having the same colored film as in Example 1 formed thereon
An integrated high dielectric constant color filter was produced.

[0062]

According to the method of manufacturing a color filter of the present invention, a color filter film (colored film) having a high dielectric constant can be formed, so that a voltage drop during driving of the liquid crystal is suppressed. Therefore, there is no need to form a contact hole or a transparent conductive film for driving the liquid crystal.
Can be used as an electrode for driving the liquid crystal, and the structure is simplified. Further, it is not necessary to use photolithography, and the number of steps is small, and a color filter with high resolution and high controllability can be provided. Further, the present invention is a simple color filter manufacturing method which can cope with a fine and complicated pixel arrangement of a color filter pattern, can easily form a black matrix, and can be mass-produced. In addition, since the colored film of the color filter of the present invention has solvent resistance, there is no need to form a protective film before forming an alignment film, which has the advantage of further reducing the number of steps. In addition, there is no need to align the color filter with the TFT substrate, and a high-precision liquid crystal display element having a large aperture ratio can be manufactured at low cost. Furthermore, T
By examining the FT substrate for non-adhesion or erroneous adhesion of the color filter layer, it becomes possible to know whether there is a disconnection defect or a short-circuit defect in the TFT circuit. Further, since the liquid crystal display element of the present invention uses the color filter as described above, it is excellent in resolution and the like, and there is no need to perform complicated alignment in its assembly, so that it can be easily manufactured at low cost. .

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a relative dielectric constant and an effective voltage of a color filter of the present invention.

FIG. 2 is a schematic diagram showing a cross-sectional configuration of a liquid crystal display device including a conventional color filter and the color filter of the present invention, where 2 (A) is a conventional example and 2 (B) is an example of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating an example of a TFT substrate on which a colored film is formed by an electrodeposition method.

FIG. 4 is a cross-sectional view of a TFT substrate for explaining a step of forming a colored film. FIG. 4A shows a protective film only on a TFT portion after an insulating protective film is provided on the entire surface of the TFT substrate. 4 (B) indicates that a colored film is formed on the pixel electrode on which the protective film is not formed.

FIG. 5 is a front view showing the structure of a TFT-integrated color filter.

[Explanation of symbols]

1 glass substrate, 2 gate electrode, 3 source electrode, 4
Conductive film (pixel electrode), 5 drain electrode, 6 etching stopper, 7 n + a-Si, 8 insulating film, 9 gate insulating film, 10 etching stopper

Continued on the front page (72) Inventor Keiji Shimizu 430 Green Tech Nakai, Nakai-cho, Ashigara-kami, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. F term (reference) 2H048 BA11 BA62 BB02 BB14 BB24 BB43 BB46 2H091 FA04Y FB02 FC06 GA03 GA13 LA12 LA30 2H092 HA04 5C094 AA43 AA44 AA45 BA03 BA43 CA19 CA24 DA14 DA15 EA04 EA07 EB02 FB03 FB12

Claims (24)

[Claims] 1. A liquid crystal display substrate in which thin film transistors and light transmitting conductive films are arranged and formed on a light transmitting substrate.
Coloring materials, high-permittivity materials having a light-transmitting particle size of 100 nm or less, and electrodepositable polymer materials having a crosslinkable group in the molecule and having a reduced solubility or dispersibility in an aqueous liquid due to a change in pH. In a state where at least the conductive film of the liquid crystal display substrate is disposed so as to be in contact with the aqueous electrodeposition liquid containing the liquid, a thin film transistor corresponding to the predetermined conductive film is driven to apply a voltage between the conductive film and the counter electrode. A method of manufacturing a color filter integrated with a thin film transistor, the method including applying and depositing a colored electrodeposition film having a high dielectric constant on the predetermined conductive film. 2. After performing a step of depositing and forming a colored electrodeposition film having a high dielectric constant on a predetermined conductive film, the electrodeposition liquid is used by changing the colorant to a colorant having another hue. The method of claim 1, wherein the step is repeated one or more times. 3. The method according to claim 1, wherein after the colored film is deposited and formed, the colored film is subjected to a heat treatment.
3. The method for producing a color filter according to item 1. 4. The thin film transistor integrated color filter according to claim 1, wherein the relative permittivity of the colored electrodeposition film after the heat treatment is 4.0 or more. Manufacturing method. 5. An insulating protective film is provided on the thin film transistor of the liquid crystal display substrate.
A method for manufacturing a color filter integrated with a thin film transistor according to claim 1. 6. The insulating protective film is formed by irradiating a liquid crystal display substrate coated with a positive-type photoresist with light from a side where a light-transmitting electrode is not formed, and then etching. The method of manufacturing a color filter integrated with a thin film transistor according to claim 1, wherein the color filter is integrated with a thin film transistor. 7. The method for manufacturing a thin film transistor integrated color filter according to claim 1, wherein the positive photoresist is a positive black photoresist. 8. The thin film transistor-integrated color according to claim 1, wherein a black matrix having an insulating property and a low dielectric constant is further formed after forming the color filter. Manufacturing method of filter. 9. The thin film transistor according to claim 1, wherein a material having low reflection is used as an electrode of the thin film transistor, and the electrode has a function similar to that of the black matrix. Item 10. The method for producing a color filter integrated with a thin film transistor according to Item 8. 10. The method according to claim 9, wherein an insulating layer is provided on the electrode. 11. The light-transmitting high-dielectric-constant material is an oxide semiconductor.
0. The method for producing a color filter integrated with a thin film transistor according to any one of items 0 to 10. 12. The method for manufacturing a color filter integrated with a thin film transistor according to claim 1, wherein the oxide semiconductor is titanium oxide. 13. The method according to claim 1, wherein the particle size of the titanium oxide is 20 nm or less. 14. The electrodepositable polymer material is a copolymer of a monomer having a hydrophobic group, a hydrophilic group and a crosslinkable group, respectively, and the ratio of the number of hydrophobic groups to the total number of hydrophilic groups is 30% or more. The method of manufacturing a color filter integrated with a thin film transistor according to claim 1, wherein the color filter is 80% or less. 15. The thin film transistor integrated color filter according to claim 1, wherein an ammonium salt that does not affect the characteristics of the thin film transistor is added to the electrodeposition liquid. Production method. 16. A mixture 1 of the high dielectric constant material and a coloring material.
The method according to any one of claims 1 to 15, wherein the electrodepositable polymer material is used in a ratio of 5.0 or less (volume ratio). Method. 17. The method according to claim 1, wherein the applied voltage is set to 10 V or less.
13. The method for producing a color filter integrated with a thin film transistor according to the above item. 18. An electrode of the thin film transistor,
The method for manufacturing a color filter integrated with a thin film transistor according to any one of claims 1 to 17, wherein two or three layers of Cr are used. 19. The thin film transistor has an internal resistance of 1
The method of manufacturing a color filter integrated with a thin film transistor according to claim 1, wherein the color filter is equal to or less than MΩ. 20. The method according to claim 1, wherein the thin film transistor is a polysilicon thin film transistor. 21. The method according to claim 1, wherein an organic alkali material is used when preparing the electrodeposition solution. 22. The method according to claim 1, wherein an ammonium salt is used when preparing the electrodeposition solution. 23. A liquid crystal display substrate in which thin film transistors and a light-transmitting conductive film are arranged and formed on a light-transmitting substrate. A color filter comprising a colored film and a black matrix having an insulating property and a low dielectric constant. 24. A color filter according to claim 23, a liquid crystal alignment film provided in contact with the color film of the color filter, and a light-transmitting conductive film provided on a light-transmitting substrate. A liquid crystal display device comprising: a substrate; and liquid crystal sealed between the liquid crystal alignment film and a counter substrate.