JP2001159709A - Method for manufacturing color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a color filter capable of easily manufacturing a multi-colored filter having high quality. SOLUTION: An alignment layer 12 is formed on a substrate 10 and projecting parts 14A, 14B,... are formed thereon by pattern-exposing a resist material, and an ink having a polymerizable liquid crystal compound is blown to recessed parts partitioned by the projecting parts 14A, 14B,... by an ink-jet system to form a colored layer 16 having hues, e.g. R, G, B, etc., then the colored layer 16 are hardened by UV irradiation to form the color filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a color filter used in a liquid crystal display device and the like, and more particularly, to a liquid crystal polymer compound capable of reducing a material loss and easily producing a high quality color filter. And a method for producing a color filter containing the same.

[0002]

2. Description of the Related Art Color filters used in color liquid crystal displays and the like generally include red (R), green (G),
Each pixel of blue (B) and a black matrix for the purpose of improving display contrast are formed between the pixels. Conventionally, such color filters are mainly those in which pigments are dispersed in a resin or dyes are dyed, and even in a manufacturing method, these colored resin liquids are applied onto a glass substrate by spin coating or the like. A color resist layer is formed by coating, and patterning by photolithography is performed to form a color filter pixel, or a color filter is produced by directly printing a colored pixel on a substrate. However, for example, a method of manufacturing a color filter by a printing method has a disadvantage that resolution of pixels is low and it is difficult to cope with a high-resolution image pattern, and a manufacturing method by a spin coating method causes a large material loss and a large area. However, there is a drawback that the coating unevenness is large when coating on the substrate.

According to the production method by the electrodeposition method, a color filter having relatively high resolution and less unevenness of the colored layer can be obtained. However, there are disadvantages that the production process is complicated and liquid management is difficult. Was. As described above, as a process for manufacturing a color filter, there has been a demand for a manufacturing method capable of easily and easily manufacturing a high-quality color filter with little material loss.

[0004] In view of the above demands, Japanese Patent No. 2794 is disclosed.
No. 242 and Japanese Patent No. 2873889 disclose a method of manufacturing a color filter by a film transfer method or an ink jet method, and a method of efficiently manufacturing a color filter with less material loss has also been proposed. However, in particular, in the ink jet method, after forming an ink receiving layer made of a water-soluble polymer, a desired pattern is subjected to a hydrophilization / hydrophobization treatment, and R, G, and R are applied to the hydrophilized portion by the ink jet method.
Since the color filter layer is obtained by spraying the ink of each color B, the obtained color filter is inferior in resolution.
Further, there is a high probability that color mixing will occur between adjacent filter layers, and the position accuracy will also be poor.

On the other hand, color filters are required to have high transmittance and high color purity. However, in recent years, a method using a dye has been developed by optimizing the type of dye and the dyeing resin. By using finely dispersed pigments, transparency and color purity have been improved. However, in recent years, liquid crystal displays (LCD)
The requirements for the transmittance and color purity of the color filters in the panel are very high. In particular, in color filters for reflective LCDs, it is difficult to achieve both white display of paper white, contrast, and color reproducibility, while dyes are dyed in a resin or pigments are dispersed in a conventional manufacturing method. Since the color filters manufactured by the method described above are all light absorption type color filters, the improvement of the color purity by the further improvement of the transmittance has almost reached the limit.

[0006] Such a light absorption type color filter is known as a polarization type color filter in which a fine pattern is formed by mixing a cholesteric liquid crystal as a main component, a polymerizable monomer, a polymerization initiator, and the like, and patterning the mixture. Have been. Since the polarized light utilizing color filter reflects and transmits a certain amount of light to display an image, the light utilization efficiency is high, and the transmittance and the color purity are more excellent than the light absorption type color filter. It has the performance which it did.

However, in the manufacturing method,
A method in which a film is formed by spin coating or the like on a substrate that has been subjected to an alignment treatment has been generally used from the viewpoint that it is preferable in that a film having a uniform thickness can be formed, but on the other hand, material loss is large. When an expensive liquid crystal material or the like is used, there is a problem that it is disadvantageous in terms of cost.

Further, in the spin coating method, it is difficult to control the film thickness in the film forming process. In particular, when a liquid crystal material is used, the performance such as reflectance is easily affected by the film thickness. It was a factor that would be higher.

Further, when a material having a liquid crystal-containing photosensitive composition layer is used, when patterning is performed by photolithography, components other than the liquid crystal component and the chiral compound, that is, the alignment movement of the liquid crystal can be suppressed. A large amount of a polymerizable monomer or a polymerization initiator could not be contained in the photosensitive composition layer, and it was difficult to achieve both color reproducibility, patterning, and curing reactivity.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention reduces material loss,
An object of the present invention is to provide a method of manufacturing a filter capable of easily manufacturing a multicolor cholesteric liquid crystal color filter having uniform thickness, high precision, and excellent transparency and color purity.

[0011]

Means for Solving the Problems The present inventors have found that the process is simple, the material loss is small, the thickness is uniform, and the transparency is high.
After extensive studies on the method of manufacturing a color filter having excellent color purity, after forming a matrix having an alignment film on the bottom surface, a colored layer containing a polymerizable liquid crystal compound in each concave portion of the matrix was formed. After forming, and then polymerizing a polymerizable liquid crystalline compound by actinic rays to cure the colored layer, the inventors have found that the above-mentioned problems can be solved, and have completed the present invention. That is, the present invention

<1> A method for manufacturing a color filter, wherein a convex portion is formed on a substrate, and ink is sprayed by an ink jet method onto a concave portion defined by the convex portion to form a colored layer in the concave portion. Forming a coating film of the liquid crystal aligning polymer compound, and wherein the ink contains a polymerizable liquid crystal compound. <2> The method for producing a color filter according to <1>, wherein the coating film made of the polymer compound having a liquid crystal orientation is subjected to a rubbing treatment. <3> After forming the colored layer by spraying the ink,
The above <1> or <2>, wherein a second ink containing a polymerizable liquid crystal polymer compound is sprayed.
2. The method for producing a color filter described in 1. above.

[0013]

Preferred embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are process diagrams showing one embodiment of the present invention. In the step (A) in FIG. 1, an alignment film 12 composed of a coating film of a polymer compound having liquid crystal alignment is formed on a substrate 10, and the alignment film 12 is preferably subjected to a rubbing treatment.

As the substrate 10 used for the color filter, a known light-transmitting substrate can be mentioned, and specifically, a glass plate, a soda glass plate having a silicon oxide film formed on the surface, a polymer film and the like can be mentioned. . It is preferable that the alignment film is formed on the surface of the various substrates before the laminating step, or that an alignment treatment, preferably a rubbing treatment, is performed by a conventional method. The rubbing angle at the time of the rubbing process is set in advance, but is not particularly limited.

It is desirable that the Tg of the alignment film 12 be higher than the alignment temperature of the liquid crystal formed on the alignment film.
In the case of a reflective LCD, a light absorbing layer (solid black) may be provided on the substrate 10 before the formation of the alignment film 12. The light absorbing layer is preferably of an ultraviolet curable type from the viewpoint of adhesion between the substrate 10 and the alignment film 12, and preferably has an alignment property.

Materials usable for forming the alignment film include, for example, polyvinyl alcohol (PVA), polyimide, polyamide, nylon, polystyrene, polyethylene, polyethylene terephthalate (PET), polybutyl terephthalate (PBT), polyester, poly Examples include cyclohexyl methacrylate, polyvinyl cinnamate, polybrene, polyacetal, and the like. The thickness of the alignment film is preferably from 0.01 to 5 μm,
01 to 1 μm is more preferable.

Next, as shown in the step (B), a black dye
A wall material layer 14 is formed by applying and drying a resist material containing (dye, pigment) or a transparent resist material containing no black pigment. The thickness of the wall material layer 14 is substantially equal to the required thickness of the target filter, and is 0.5 to 1
0 μm, preferably 1-4 μm. As the resist material, in the case of a negative type, a composition obtained by adding a siloxane resin and an alkoxy-containing silicone resin to a photosensitive resin composition including a resin such as an acrylic resin, polyvinylpyrrolidone, polyvinyl alcohol, and a hydroxypropylcellulose derivative and a photosensitive agent. Or a silicone-containing photosensitive resin composition obtained by modifying them. For positive type,
Polysilane and the like are preferable, and a photosensitive resin composition having a disilane structure or a siloxane bond is more preferable.

The wall material layer 14 is preferably formed by spin coating, roll coating, bar coating, spray coating, dip coating, or the like.

Next, as shown in step (C), after the active light is subjected to pattern exposure using the photomask 16 and development and rinsing are performed, as shown in step (D), a predetermined pitch.
Projections (walls) 14A, 14B,... Having width and height are formed. A black matrix is formed by these steps. When the transparent resist material is applied and dried to form the wall material layer 14, the projections (walls) 14A, 14B,.
-It can be colored black after the is formed. In this case, the entire substrate on which the convex portions (walls) 14A, 14B,... Are formed is immersed in a solution in which a dye is dissolved or a liquid in which a pigment is dispersed, and then the dye or pigment is immersed in the convex portions (walls) 14A, 14A.
B ... can be immobilized in the photosensitive resin composition, and for this method, a photosensitive resin composition using polysilane is particularly suitable. Further, when the black matrix has a property of horizontally aligning the liquid crystal, the pattern is exposed to actinic rays, and then, when development is performed, if development processing is stopped in the middle, the vicinity of the bottom of the wall material layer 14 remains. Can be used as a light absorbing layer.

When pattern exposure is performed using a resist material containing no black pigment (dye or pigment), and then the dye is fixed, when pattern exposure is performed using a resist material containing a black pigment (dye or pigment) Sensitivity compared to
It has excellent resolution and a desired black matrix is formed.

Next, as shown in the step (E), the projections (walls)
The colored layer 16 is formed by spraying ink containing a polymerizable liquid crystal compound by an ink jet method on the concave portions divided by 14A, 14B,. When the colored layer 16 is formed, ink is applied to the projections (walls) 14A, 14B,.
In order to prevent the protrusions (walls) 14A, 14B,. As the ink-repellent treatment, a method in which at least a portion including the projections (walls) 14A, 14B,.

As the above-mentioned ink jet system, a bubble jet type using an electrothermal converter or a piezo jet type using a piezoelectric element can be used as an energy generating element.

In the present invention, the ink contains a polymerizable liquid crystal compound. The polymerizable liquid crystal compound referred to herein is
The case where the liquid crystal compound itself has a polymerizable group or the case where the liquid crystal compound has a polymerizable monomer together with the liquid crystal compound is included, and a nematic liquid crystal compound is particularly preferable as the liquid crystal compound.

The preferred composition for the ink contains a nematic liquid crystal compound and a chiral compound, and further contains a solvent, a polymerizable monomer, a photopolymerization initiator, a binder resin,
It contains a thermal polymerization inhibitor and, if necessary, can contain a surfactant, a thickener, a dye, a pigment, an ultraviolet absorber, a gelling agent, and the like.

The nematic liquid crystalline compound is characterized in that its liquid crystal phase is fixed below the liquid crystal transition temperature, and has a refractive index anisotropy Δn of 0.10 to 0.10.
It can be appropriately selected from a liquid crystal compound of 0.40, a polymer liquid crystal compound, and a polymerizable liquid crystal compound. The helical pitch has three or more types of structural changes, and may be right-handed or left-handed. The ink may be 1) in a liquid crystal state at the time of spraying, or 2) in an isotropic liquid state dissolved in a solvent. In the case of 2), it is preferable to evaporate the solvent by heating after spraying.

After spraying each R, G, B ink,
It is preferable that the substrate is allowed to stand horizontally and alignment ripening is performed until a liquid crystal state is exhibited. In addition, it is preferable to disperse the helical axis of the liquid crystal compound in order to enlarge the field of view. From this point, the air interface of the liquid crystal in each cell (concave portion) is greatly convex, or conversely, greatly concave. Is preferred.
Further, it is desirable to control the alignment on the air interface side of the liquid crystal.

Specific examples of the nematic liquid crystal compound include the following compounds, but the present invention is not limited to these nematic liquid crystal compounds.

[0028]

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[0029]

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[0030]

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In the above formula, n represents an integer of 1 to 1000. In each of the exemplified compounds, the side chain linking group is
Those having the following structures can also be mentioned as suitable.

[0032]

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Among the above, the nematic liquid crystal compound is preferably a nematic liquid crystal compound having a polymerizable group or a crosslinkable group in the molecule from the viewpoint of ensuring sufficient curability and heat resistance of the layer. .

In the present invention, from the viewpoint of improving the hue and color purity of the liquid crystal compound together with the liquid crystal compound, it is desirable that the ink contains isomanide, catechin, isosorbide, fencon, carvone, and a chiral compound as exemplified below.

[0035]

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[0036]

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The chiral compound may be a photoreactive chiral compound in which the helical pitch induced in the cholesteric liquid crystal composition is changed by light irradiation (ultraviolet light to visible light to infrared light). The necessary molecular structural unit has a chiral site and a site that undergoes a structural change upon irradiation with light, and these sites are preferably contained in one molecule. The chiral compound preferably has a large force for inducing the helical structure of the cholesteric liquid crystal composition. For this purpose, it is preferable that the chiral site is located at the center of the molecule and the periphery thereof has a rigid structure, and the molecular weight is 300 or more is preferable. Further, in order to increase the helical structure inducing force by light irradiation, it is preferable to use a material having a large degree of structural change by light irradiation, and to bring a chiral part close to a part that causes structural change by light irradiation. Furthermore, as a chiral compound having high solubility in a nematic liquid crystal compound, the solubility parameter S
Those having a P value close to that of a nematic liquid crystalline compound are desirable. When the chiral compound has a structure in which one or more polymerizable bonding groups are introduced, the heat resistance of the cholesteric liquid crystal layer is improved.

Examples of photoreactive sites whose structure is changed by light irradiation include photochromic compounds (Kingo Uchida, Masahiro Irie, Kagaku Kogyo, vol. 64, 640p, 1999;
Kingo Uchida, Masahiro Irie, Fine Chemical, vol. 28
(9), 15p, 1999).
For example, the following are mentioned.

[0039]

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In the above, R ¹ and R ² are an alkyl group, an alkoxy group and an alkanoyloxy group.

The photoreactive site may be one which undergoes decomposition, addition reaction, isomerization, dimerization reaction or the like upon irradiation with light, and undergoes an irreversible structural change. Further, as the chiral site, for example, * of a compound exemplified below is used.
An asymmetric carbon in which different groups are bonded to four bonds such as the carbon atoms of the mark, respectively, is equivalent (Hiroyuki Nohira, Chemical Review, No. 22 Liquid Crystal Chemistry, 73p: 1994).

[0042]

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Further, as a photoreactive chiral material having both a chiral site and a photoisomerizable portion, the following compounds can be exemplified.

[0044]

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Furthermore, the chiral compound may be a compound in which the helical pitch induced in the nematic liquid crystal compound changes depending on the temperature because the twisting force has a large temperature dependency.
The relationship between the properties required for this chiral compound and its molecular structure is as follows. (1) The force for inducing the chain line structure is large. To this end, the chiral site is located at the center of the molecule, and the periphery thereof is a rigid structure. The molecular weight is preferably 300 or more. (2) The helical structure induced force by temperature is large,
For this purpose, it is preferable that there are a plurality of conformers in which the bond near the chiral site is rotated. (3) The solubility in a nematic liquid crystal compound is large. For this purpose, it is preferable that the SP value of the solubility parameter is similar between the nematic liquid crystal compound and the chiral compound. (4) In addition, a structure in which one or more polymerizable bonding groups are bonded is preferable because the heat resistance of the film is increased.

Examples of the chiral compound having such properties include the following compounds.

[0047]

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Therefore, in the ink of the present invention, the nematic liquid crystal compound itself is selected and the combination of the nematic liquid crystal compound and the chiral site is set to change into different helical structures different from each other, and a desired hue is obtained. It is desirable to present it.

Examples of the polymerizable monomer contained in the ink include a monomer having an ethylenically unsaturated bond, and examples thereof include polyfunctional monomers such as pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate. . Specific examples of the monomer having an ethylenically unsaturated bond include the following compounds, but the present invention is not limited thereto.

[0050]

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Further, after spraying the ink, the above-mentioned photopolymerization initiator can be added for the purpose of fixing the helical pitch of the liquid crystal molecules and further improving the film strength of the colored layer. The photopolymerization initiator can be appropriately selected from known ones. For example, p-methoxyphenyl-2,4-bis (trichloromethyl) -s-triazine, 2- (p-butoxystyryl)- 5-trichloromethyl 1,3,4-oxadiazole, 9-phenylacridine, 9,10-dimethylbenzphenazine, benzophenone / Michler's ketone, hexaarylbiimidazole / mercaptobenzimidazole, benzyldimethyl ketal, thioxanthone / amine and the like. Can be

Examples of the binder resin include polystyrene compounds such as polystyrene and poly-α-methylstyrene, cellulose resins such as methylcellulose, ethylcellulose and acetylcellulose, acidic cellulose derivatives having a carboxyl group in the side chain, polyvinylformal, Acetal resins such as polyvinyl butyral, JP-A-59-44615, JP-B-54-34327,
JP-B-58-12577, JP-B-54-25957
JP-A-59-53836, JP-A-59-7104
No. 8, methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer, partially esterified maleic acid copolymer and the like.

Homopolymers of alkyl acrylates and homopolymers of alkyl methacrylates are also mentioned. In these, alkyl groups are methyl, ethyl, n-propyl, n-butyl, iso-
-Butyl group, n-hexyl group, cyclohexyl group, 2-
Examples thereof include an ethylhexyl group. In addition, a polymer having a hydroxyl group to which an acid anhydride is added, a benzyl (meth) acrylate / (homopolymer of methacrylic acid) acrylic acid copolymer or benzyl (meth) acrylate / (meth) acrylic acid / other monomer And the like.

Examples of the polymerization inhibitor added for improving the storage stability include hydroquinone, hydroquinone monomethyl ether, phenothiazine, benzoquinone, and derivatives thereof.

Next, as shown in step (F), the liquid crystal compound is polymerized by heating or irradiating the entire surface of the colored layer with ultraviolet rays.
The coloring layer is cured by fixing the alignment state of the liquid crystal compound. It is also preferable that the liquid crystal compound is vitrified by rapid cooling after the liquid crystal compound is subjected to alignment ripening in a heated state.
Further, post-baking or post-exposure treatment may be performed for the purpose of sufficiently curing the film. Further, it is preferable to wash the colored layer after curing the colored layer in order to prevent elution of low molecules in the colored layer after forming the color filter. .

Further, a second ink containing a polymer liquid crystal compound having a different hue or helical structure may be sprayed on the colored layer. There are advantages that can be.
The second ink may be an ink containing a pigment.
In this case, an alignment film can be formed over the coloring layer.

Preferably, a protective film 18 is formed on the colored layer 16. The protective film is preferably a photo-curing type, a thermosetting type, a resin of a combination of light and heat, or an inorganic film formed by vapor deposition, sputtering, or the like. After the protective film 18 is formed,
If necessary, the protection film 18 is flattened.

[0058]

Example 1 A glass substrate was subjected to alkali ultrasonic cleaning, and then a polyimide alignment film LX-1400 manufactured by Hitachi Chemical DuPont was spin-coated, dried at 80 ° C. for 20 minutes, and then heated at 250 ° C. for 60 minutes. This was rubbed, and then spin-coated with a carbon black-containing resist material.
Dried for minutes. After exposing this film to ultraviolet light using a photomask, development and rinsing were performed to obtain a pitch of 100 μm and a width of 30 μm.
A substrate having a height of 2.5 μm and a height of 2.5 μm was obtained. Next, using an ink jet recording apparatus, R, G, and B inks having the following compositions are sprayed onto the openings (concave portions) of the black matrix, and then heat-treated at 115 ° C. for 5 minutes. Irradiation performed the dura. Thereafter, post-baking was performed at 250 ° C. for 10 minutes to obtain a color filter substrate.

[0059]

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The substrate was irradiated with left circularly polarized light and right circularly polarized light, and the reflected light was observed with a microscope. As a result, a reflected image was observed at each pixel (concave portion) for the right circularly polarized light. On the other hand, for left circularly polarized light, no reflected light is observed,
It was confirmed that a desired color filter was formed.

[0061]

As described above, according to the present invention, a convex portion is formed on a substrate, and ink is sprayed on a concave portion divided by the convex portion by an ink jet method to form a colored layer in the concave portion. In addition, a color filter having excellent hue and color purity can be manufactured by selecting a liquid crystal compound, a chiral compound, and the like.

[Brief description of the drawings]

FIG. 1 shows (A) a method for producing a color filter of the present invention.
It is a schematic process drawing showing a process-(C) process.

FIG. 2 (D) of the method for producing a color filter of the present invention.
It is a schematic process drawing showing a process-(G) process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 12 Orientation film 14 Wall material layer 16 Photomask 18 Coloring layer

Claims (3)

[Claims] 1. A method of manufacturing a color filter, wherein a convex portion is formed on a substrate, and ink is sprayed by an ink jet method onto a concave portion separated by the convex portion to form a colored layer in the concave portion. A method for producing a color filter, comprising forming a coating film of the polymer compound having liquid crystal orientation, and wherein the ink contains a polymerizable liquid crystal compound. 2. The method for producing a color filter according to claim 1, wherein the coating film made of the polymer compound having a liquid crystal orientation is subjected to a rubbing treatment. 3. The color filter according to claim 1, wherein a second ink containing a polymerizable liquid crystal polymer is sprayed after forming the colored layer by spraying the ink. Manufacturing method.