JP2002309103A - Liquid crystalline composition, color filter, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystalline composition which allows omitting of an oriented film at the one side in the manufacture of a color filter by con trolling the orientation of liquid crystalline molecules and giving a uniform thick film with no coating imperfection by controlling the inclusion of foreign matters, to provide a color filter having a uniform selective reflection wave length and a sufficiently high reflectance made by using the above liquid crystal line composition, and a liquid crystal display device using the above color filter. SOLUTION: The liquid crystalline composition is characterized by containing at least a liquid crystalline compound having at least one polymerizable group, a chirality-generating agent, a polymerization initiator, an air-interfacial orientating agent and a solvent, and by having a viscosity of 1-100 cP.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal composition, a color filter manufactured using the liquid crystal composition, and a liquid crystal display device provided with the color filter.

[0002]

2. Description of the Related Art In addition to portable information terminals, personal computers, word processors, amusement devices, television devices, and the like, color filters are increasingly being used for various electronic devices and display panels for electric devices. Conventionally, a display device using a liquid crystal is incorporated in these devices, but this display device has an advantage of low power consumption and thinness. These display devices are broadly divided into a transmission type display device having a backlight light source and a reflection type display device of a front light type having no light source or using a light guide plate on the entire surface. , Color filters are used. For example, color filters used for color liquid crystal displays and the like are generally
Each pixel of red (R), green (G), and blue (B) is formed with a black matrix formed in the gap between the pixels to improve display contrast.

[0003] Such a color filter router has conventionally been
What is manufactured using a pigment dispersion method or a dyeing method is the mainstream. The pigment dispersion method is a method in which a pigment is dispersed in a photoresist and applied to a substrate glass to perform a pattern exposure / development step, and is a method excellent in patterning edge, resolution, film uniformity, and the like. However, there are problems such as the necessity of a photoresist process and the fact that color adjustment cannot be performed as easily as using a dye because a pigment is used. In addition, when a photoresist is applied on a substrate by using the spin coating method, there are disadvantages in that the material loss is large and the application unevenness when applying the photoresist on a large-area substrate is large. The dyeing method is a method of dyeing a transparent resin pattern obtained by imparting photosensitivity to gelatin or the like later.The light transmittance is high based on the transparency of the dye, and the chromaticity is adjusted by abundant types of the dye. Although it has the feature of being easy, it requires a drawback that the number of steps such as a photoresist step is larger than that of the pigment dispersion method.

[0004] In addition, as a method of manufacturing a color filter, a printing method, an electrodeposition method, an ink jet method, and the like are known. Although the above printing method has a high material utilization rate, it is a method of printing each color one by one sequentially, so that it is difficult to align the pattern of each color, the resolution of pixels is low, the film thickness is not uniform, and the high definition is high. There is a drawback that it is difficult to cope with the formation of a complicated image pattern. According to the electrodeposition method,
Although it is possible to obtain a color filter having relatively high resolution and little unevenness of the colored layer, it has a disadvantage that the manufacturing process is complicated and liquid management is difficult. In the case of the ink jet method, there are problems of resolution and color mixing between adjacent pixels.

Each of the color filters is a light absorption type color filter, and in principle, about 1% of the light from the light source.
Since only / 3 can be transmitted, the brightness is not sufficient. To compensate for this drawback, for example, in the case of a transmissive display device, it is conceivable to increase the brightness of the backlight. However, there is a problem that the power consumption increases and the advantages of the liquid crystal display device are lost.

To solve these problems, US Pat.
No. 614 proposes a color filter using a cholesteric polarizer which does not require a liquid developing step. Cholesteric polarizer selectively reflects circularly polarized light of a specific wavelength, because it has the property of transmitting circularly polarized light of other wavelengths, unlike a color filter if the color resin,
By reusing transmitted light, utilization efficiency can be increased, and a substantially bright color filter can be formed. Therefore, this type of color filter is suitable for a reflective liquid crystal display. Further, since a pattern having different selective reflection wavelengths can be formed in the same layer without the need for a developing step, it is advantageous in terms of cost.

The present applicant has previously described a method for forming a color filter layer by spraying an ink containing a polymerizable liquid crystal compound by an ink jet method as a color filter utilizing such selective reflection of a cholesteric liquid crystal phase. An application was filed (Japanese Patent Application No. 11-343666).

The present applicant has further filed an application for a method of forming a color filter by irradiating light to a layer containing a photoreactive chiral agent having a specific structure in a polymerizable liquid crystalline compound. No. 2000-193142, Japanese Patent Application No. 2000-193143). The photoreactive chiral agent has a chiral site and a site that undergoes a structural change due to light irradiation. For example, the photoreactive chiral agent greatly changes the twisting power (HTP) of the helical structure of the liquid crystal in accordance with the amount of irradiation. , Green (G) and red (R).

In the production of a color filter as described above, generally, first, a polymerizable liquid crystal compound and a photoreactive chiral agent, or those obtained by adding a polymerizable monomer or the like thereto, are dissolved in an organic solvent. A step of applying the solution to a glass substrate or the like is performed. However, since the polymerizable liquid crystal compound is difficult to dissolve in various organic solvents, the content of the liquid crystal compound in the solution is limited, and the viscosity of the solution is low. Cannot be formed. For such a problem, it is conceivable to add a small amount of a polymer, but since the addition of the polymer disturbs the alignment of the liquid crystal,
It is impossible to produce a high-performance color filter. Japanese Patent Application Laid-Open No. 2000-154168 describes a solution-coatable cross-linkable liquid crystalline composition containing a specific high molecular weight acrylic photoisomerizable chiral compound and a liquid crystal polymer. This composition can adjust the viscosity by changing the ratio of the solvent, but has the disadvantage that it takes time to reorient the liquid crystal.

On the other hand, when a layer containing a liquid crystal composition (color filter forming layer) is formed by coating in the production of a color filter, particularly in the case of a low-molecular liquid crystal, the liquid crystal molecules should be horizontal (to the substrate) on the substrate side. Even if the alignment treatment is performed, the liquid crystal molecules stand vertically on the air interface side because one side of the color filter formation layer is at the air interface, and the tilt angle (pretilt angle) of the liquid crystal molecules toward the thickness direction of the color filter formation layer is increased. A continuously changing state occurs. For this reason, it is usually necessary to sandwich both sides of the layer with an alignment film. However, when the liquid crystal composition is polymerized and used as an optical film, at least one side of the alignment is required after polymerization to reduce the weight and thickness. It is necessary to peel off the film, and there is a problem that an increase in steps such as installation and removal of an alignment film and an increase in waste material are involved.

[0011]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and it is possible to omit the alignment film on one side by controlling the alignment of liquid crystal molecules in the production of a color filter. And a liquid crystal composition capable of obtaining a uniform and thick film free from coating defects by suppressing the incorporation of dust, and a color filter having a uniform selective reflection wavelength and sufficiently high reflectance manufactured using the liquid crystal composition. And an object of the present invention is to provide a liquid crystal display device using the color filter.

[0012]

Means for solving the above problems are as follows. <1> At least a liquid crystalline compound having at least one polymerizable group, a chiral agent, a polymerization initiator, an air interface aligning agent and a solvent, and having a viscosity of 1 to 100 cP (mPa ·
s). <2> The liquid crystalline composition according to <1>, wherein the surface tension is 50 mN / m or less. <3> The chiral agent is a photoreactive chiral agent <1.
> Or <2>.

<4> For use in a liquid crystal display device, at least a step of forming an alignment film on a substrate, a step of providing a color filter forming layer made of a liquid crystalline composition on the alignment film, A color filter manufactured by a method for manufacturing a color filter having a step of irradiating an ultraviolet ray, wherein the liquid crystal composition is <1>
A color filter, which is the liquid crystalline composition according to any one of <3> to <3>. <5> The color filter according to <4>, wherein the color filter forming layer is formed by applying any one of a bar coating method, a spin coating method, and a slit coating method. <6> A liquid crystal display device including the color filter according to <4> or <5>.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Liquid Crystal Composition] The liquid crystal composition according to the present invention comprises at least a liquid crystal compound having at least one polymerizable group, a chiral agent, a polymerization initiator, an air interface alignment agent (interface Activator) and a solvent. The liquid crystal composition has a viscosity of 1 to 100 cP (mPa ·
s), preferably 20 to 100 cP, more preferably 50 to 100 cP. The viscosity is an absolute viscosity value measured at 20 ° C. with a Visco Tester VT550 manufactured by Haake. By setting the viscosity of the liquid crystalline composition to 1 to 100 cP, the coatability becomes excellent. Therefore, when forming the layer by applying the liquid crystalline composition, a layer having a uniform thickness is formed. It is possible to do.

Further, the surface tension of the liquid crystalline composition is preferably 50 mN / m or less, more preferably 40 mN / m or less, in consideration of coatability.
More preferably, it is not more than mN / m. This surface tension is a value measured under the condition of 20 ° C. using a surface tension meter CBVP-A3 manufactured by Kyowa Interface Science Co., Ltd.

(Liquid Crystal Compound Having at least One Polymerizable Group) In the liquid crystal composition of the present invention, a (low molecular weight) liquid crystal compound having at least one polymerizable group (hereinafter also referred to as a polymerizable liquid crystal compound). ) Is preferably a nematic liquid crystal compound having a polymerizable group. The polymerizable group of the liquid crystal compound ensures sufficient curability and improves the heat resistance of the layer.

Specific examples of the liquid crystalline compound having a polymerizable group include the following compounds. However,
The present invention is not limited to these.

[0018]

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[0019]

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[0020]

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In the above formula, n represents an integer of 1 to 1000. In each of the above exemplified compounds, those in which the connecting group of the aromatic ring is changed to the following structure can also be mentioned as suitable compounds.

[0022]

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The content of the liquid crystal compound is 30 to 99.9% by mass based on the mass of the solid content of the liquid crystal composition.
Is preferable, and 50 to 95% by mass is more preferable. When the content is less than 30% by mass, the orientation is insufficient and a desired selective reflection color may not be obtained.

(Chiral Agent) As the chiral agent, a photoreactive chiral agent is preferable. In addition to the photoreactive chiral agent, for example, a heat-reactive chiral agent or a chiral agent which does not react to heat, light or the like can be used. It can also be used.

The photoreactive chiral agent is a compound having a chiral site and a photoreactive site that undergoes a structural change upon irradiation with light, and for example, a compound that greatly changes the twisting power (HTP) of the helical structure of the liquid crystal according to the amount of irradiation. is there. In order to increase the helical structure inducing force by light irradiation, it is preferable that the degree of structural change by light irradiation is large. Further, the photoreactive chiral agent preferably has a solubility parameter SP value close to that of the liquid crystalline compound. Further, when the photoreactive chiral agent has a structure in which one or more polymerizable bonding groups are introduced into the molecule, the heat resistance of the liquid crystal phase is improved.

Examples of photoreactive sites whose structure is changed by light irradiation include photochromic compounds (Kingo Uchida, Masahiro Irie, Chemical Industries, vol. 64, 640p, 1999,
Kingo Uchida, Masahiro Irie, Fine Chemical, vol. 28
(9), 15p, 1999).
Further, the structural change means a decomposition or addition reaction, isomerization, dimerization reaction, or the like caused by light irradiation on a photoreactive site, and the structural change may be irreversible. Examples of the chiral moiety include, for example, Hiroyuki Nohira, Chemical Review, N
o. The asymmetric carbon described in 22 Chemistry of Liquid Crystals, 73p: 1994, and the like correspond thereto.

The photoreactive chiral agent used in the present invention includes, for example, the photoreactive chiral agents described in paragraphs [0044] to [0047] of Japanese Patent Application No. 11-343666 and the paragraph of Japanese Patent Application No. 2000-193142. [002
Paragraph [0019] of Japanese Patent Application No. 2000-380919, in addition to the photoreactive chiral agents described in [1] to [0029].
To [0043], Japanese Patent Application 2000
Optically active compounds described in paragraphs [0020] to [0044] of JP-A-381001, optically active compounds described in paragraphs [0016] to [0040] of Japanese Patent Application No. 2000-381002, and paragraphs of Japanese Patent Application No. 2000-381003 [ 001
5] to [0036], optically active compound, Japanese Patent Application No. 20
Nos. 00-381966, paragraphs [0017] to [005].
0], Japanese Patent Application No. 2000-3819.
No. 67, paragraphs [0018] to [0044], and optically active compounds described in Japanese Patent Application No. 2000-382515, paragraph [0].
020] to [0049].

(Polymerization Initiator) In order to fix the helical structure in which the twisting force of the liquid crystal is changed by utilizing the polymerization reaction by the polymerizable liquid crystal compound, and to further improve the strength of the liquid crystal composition after the fixing. And a polymerization initiator. As the polymerization initiator, a photopolymerization initiator is preferable, but in addition to the photopolymerization initiator, for example, a thermal polymerization initiator or the like can also be used.

The photopolymerization initiator preferably has a photosensitive wavelength range different from that of the photoreactive chiral agent. Here, having different photosensitive wavelengths means that both photosensitive central wavelengths do not overlap.
When the photosensitive wavelength region of the photoreactive chiral agent is different from the photosensitive wavelength region of the photopolymerization initiator, the irradiation of light for changing HTP and the irradiation of light for photopolymerization do not affect each other. Therefore, when imagewise exposed to change the HTP, photopolymerization does not proceed, so that patterning with the HTP change rate as set becomes possible, while photopolymerization to fix the helical structure is performed. Is
The photoreactive chiral agent does not react to light, and the formed HTP change pattern can be reliably immobilized, so that selective reflection can be achieved as set.

The photopolymerization initiator can be appropriately selected from known ones, for example, p-methoxyphenyl-2,4-bis (trichloromethyl) -s-triazine, 2- (p-butoxy) (Styryl) -5-trichloromethyl-1,3,4-oxadiazole, 9-phenylacridine, 9,10-dimethylbenzphenazine, benzophenone / Michler's ketone, hexaarylbiimidazole / mercaptobenzimidazole, benzyldimethylketal, thioxanthone / Amines and triarylsulfonium hexafluorophosphate. In addition, bisacylphosphine oxides such as bis- (2,4,6-trimethylbenzoyl) phenylphosphine oxide described in JP-A-10-29997 and the like, and DE4 such as Lucirin TPO and the like.
Acylphosphine oxides described in JP 230555 and the like.

The amount of the photopolymerization initiator to be added is preferably 0.1 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the liquid crystal composition. If the amount is less than 0.1% by mass, the curing efficiency at the time of light irradiation is low, so that it may take a long time. If the amount exceeds 20% by mass, the light transmittance from the ultraviolet region to the visible light region may be required. May be inferior.

(Air Interface Orienting Agent)
A surfactant having an excluded volume effect. Here, having the excluded volume effect means controlling the alignment of the liquid crystal (molecule) on the air interface side, that is, the liquid crystal at the air interface on the layer surface when, for example, a layer containing the liquid crystal composition is formed by coating. Is to control the spatial orientation state of the three-dimensionally. Specifically, this means controlling the pretilt angle of liquid crystal molecules on the air interface side.

The preferred molecular structure of the air interface aligning agent includes a flexible hydrophobic portion and a molecularly rigid unit having at least one cyclic unit (hereinafter referred to as a rigid portion). That is. Note that, depending on the type of the liquid crystalline compound used, the flexible hydrophobic portion can be a perfluoro chain or a long alkyl chain. Since the hydrophobic portion is flexible, the hydrophobic portion can be effectively arranged on the air side. Further, the air interface alignment agent may be a short molecule having a number of molecules of about several hundreds, or may be a polymer or an oligomer in which the molecules are linked. It is also possible to add a polymerizable functional group depending on the purpose.

When such an air interface aligning agent is contained, the flexible hydrophobic portion of the air interface aligning agent exists in the air interface direction, the rigid portion exists in the liquid crystal molecule direction, and the rigid portion further exists. Are planar and are arranged parallel to the air interface, so that the liquid crystal molecules can be arranged parallel to the air interface. On the other hand, if the rigid portions are arranged perpendicular to the air interface, it becomes possible to arrange the liquid crystal molecules perpendicular to the air interface. Specifically, nonionic surfactants are preferable, and for example, the following compounds are preferable.

[0035]

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[0036]

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The amount of the air interface aligning agent added is preferably such that the surface of the layer containing the liquid crystal composition on the air interface side is covered by about one molecule.
5-5 mass% is preferable, and 0.5-2 mass% is more preferable. If the amount is less than 0.05% by mass, the effect may not be exhibited. If the amount exceeds 5% by mass,
In some cases, the air interface alignment agent itself associates to cause phase separation with the liquid crystal. Although the surface tension is reduced by containing the air interface aligning agent, a surfactant other than the air interface aligning agent may be used in combination for the purpose of further lowering the surface tension and improving coating properties. Can also.

(Solvent) The solvent used in the liquid crystal composition of the present invention includes the polymerizable liquid crystal compound, a chiral agent, a polymerization initiator,
And an air interface aligning agent to be dissolved to form a solution suitable for coating. As the solvent, an organic solvent such as 2-butanone, cyclohexanone, methylene chloride, chloroform, and N-methyl-2-pyrrolidone is used, although it depends on the components of the liquid crystal composition to be used.

The liquid crystalline composition of the present invention can be obtained by dissolving the above-mentioned polymerizable liquid crystal compound, chiral compound, polymerization initiator, and air interface alignment agent in the above-mentioned solvent. In this case, in particular, as the solvent, a solvent having a relatively high volatility such as chloroform and a solvent having a relatively low volatility such as cyclohexane may be appropriately mixed to adjust the drying speed of the coating solution. For the purpose of increasing the viscosity, chloroform, cyclohexane or the like is preferable, whereby the viscosity can be easily adjusted to the above range.

The liquid crystalline composition of the present invention includes the polymerizable liquid crystal compound, a chiral agent, a polymerization initiator, an air interface alignment agent,
In addition to the solvent and the solvent, if necessary, other components such as a gelling agent, a polymerizable monomer, a binder resin, a polymerization inhibitor, a thickener, a dye, a pigment, and an ultraviolet absorber can be contained.

(Gelling Agent) As the gelling agent, a compound that gels an organic solvent is preferably used. The liquid crystalline composition to which the gelling agent is added, at a temperature at which the liquid crystalline composition is applied, for example, at a temperature of about 40 to 100 ° C., the gel state is released and a viscosity suitable for application is exhibited.
Immediately after the application, the temperature of the applied layer is lowered, and when the temperature of the applied layer becomes, for example, normal temperature, the applied layer is gelled or solidified. The liquid crystalline composition to which the gelling agent is added is excellent in application suitability and can form a uniform and thick color filter forming layer. In addition, when the liquid crystalline composition is applied to the substrate, the liquid can be prevented from flowing around the back surface of the substrate. When a color filter is manufactured from this liquid crystalline composition, a thick and uniform color filter film can be obtained, so that a selective reflection wavelength is uniform, there is no color unevenness, and the color filter has a sufficient reflectance. Also, although the reason is not clear, the resolution also increases.

As the gelling agent, any compound can be used without particular limitation as long as it is a compound capable of gelling a solvent. For example, the following compounds can be used. The gelling agent can be efficiently gelled by adding a small amount thereof in consideration of the combination with the solvent used, and a gelling agent that does not adversely affect the alignment of the liquid crystal and does not absorb visible light is appropriately selected. You. In addition, on pages 1 to 13 of “Surface”, Vol. 36, No. 6, various gelling agents and solvents capable of causing the gelling agents to gel are described in detail.

[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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The above-mentioned gelling agent depends on the kind of the gelling agent, but can be generally added in an amount of 0.1 to 5% by mass, preferably 1 to 2% by mass based on the solvent used. If the amount is less than 0.1% by mass, a required gel state cannot be achieved, and if the amount is more than 5% by mass, alignment defects are likely to occur. Further, when the gelling agent is added,
By reducing the amount of addition, the liquid crystalline composition is not completely gelled, and it is also possible to apply the composition in a semi-gelled state or a viscous state.In this case, it is possible to apply the composition at room temperature. it can. Among these compounds, tridecyl-1,3,5-benzenetricarboxamide is a preferred gelling agent for use in such a coating form.

(Polymerizable Monomer) The liquid crystalline composition of the present invention may contain a polymerizable monomer. When the polymerizable monomer is used in combination, the distribution of the selective reflection wavelength is formed (patterned) by changing the torsional force of the liquid crystal by light irradiation, and then the helical structure (selective reflectivity) is fixed, and the liquid crystal property after the fixing is fixed. The strength of the composition can be further improved.
However, when the liquid crystal compound has an unsaturated bond in the same molecule, it is not always necessary to add.

Examples of the polymerizable monomer include a monomer having an ethylenically unsaturated bond. Specifically, in addition to polyfunctional monomers such as pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate, Compounds shown can be mentioned,
However, the present invention is not limited to these.

[0051]

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The amount of the polymerizable monomer added is 0.5 to 50% by mass based on the mass of the solid content of the liquid crystal composition.
Is preferred. If the amount is less than 0.5% by mass, sufficient curability may not be obtained, and
If it exceeds 0% by mass, the orientation of the liquid crystal is hindered, and sufficient color formation may not be obtained.

[Color Filter] The color filter of the present invention can be produced from the above-mentioned liquid crystalline composition.
The color filter of the present invention is an embodiment in which a color filter forming layer is provided on a desired substrate, and another layer such as a protective film may be provided. Two or more color filter forming layers can be laminated.

The formation of the color filter forming layer may be performed by directly applying the liquid crystal composition to the color filter substrate, or by temporarily adhering the color filter forming layer formed on the temporary support to the color filter substrate, This is performed by a transfer method for peeling off the support.

When a photoreactive chiral agent is used in the production of a color filter, when the photoreactive chiral agent is irradiated with light (ultraviolet rays) in the photosensitive wavelength region, the photoreactive chiral agent is subjected to photoreaction (isomerization) in accordance with the amount of light. , Decomposition, addition, dimerization, etc.)
As a result, the pitch of the liquid crystal spiral structure of the color filter forming layer is changed. Therefore, if the light irradiation intensity is changed for each desired region of the color filter forming layer, light irradiation is performed.
A change in the pitch of the helical structure occurs according to the irradiation intensity, and selective reflection of light having a wavelength corresponding to the pitch occurs, so that a plurality of colors can be exhibited. In order to irradiate each region with a different amount of light, for example, a method of exposing through an exposure mask manufactured by changing the light transmittance imagewise is preferably used. In this method, one light irradiation
This is a preferable method because a color filter forming layer having a different degree of photoreaction in an image-like manner (as a result, the helical pitch of the liquid crystal in the color filter forming layer can be changed in an image-like manner) can be formed.

Thereafter, light (ultraviolet rays) is applied to the entire surface of the color filter forming layer to be photopolymerized (cured), thereby fixing the changed helical pitch of the liquid crystal phase. In this case, as described above, the wavelength region of light that causes a photoreaction to the photoreactive chiral agent (the photosensitive wavelength range of the photoreactive chiral agent)
And the wavelength region of light to be photopolymerized (the photosensitive wavelength region when a polymerization initiator is used) is preferably different.

The wavelength of light that causes a photoreactive chiral agent to undergo a photoreaction can be set in the light-sensitive wavelength range of the photoreactive chiral agent, particularly at a wavelength close to the light-sensitive peak wavelength, so that sufficient patterning sensitivity can be obtained. It is preferable in that it can be obtained. Also,
It is preferable to set the wavelength of the light to be photopolymerized to a light-sensitive wavelength region of the photopolymerization initiator, particularly to a wavelength close to the light-sensitive peak wavelength, in that sufficient photopolymerization sensitivity can be obtained.
The irradiation intensity of these lights can be appropriately selected so as to obtain sufficient light sensitivity.

Hereinafter, a method for manufacturing a color filter according to an embodiment of the present invention will be described with reference to the drawings. The color filter of the present invention includes, at least, a step of forming an alignment film on a substrate, a step of providing a color filter formation layer made of the above-described liquid crystalline composition on the alignment film, and irradiating the color filter formation layer with ultraviolet rays. It is manufactured through a process. Further, in addition to the above steps, a step of performing a rubbing treatment on the alignment film as shown below may be provided.

In the color filter according to one embodiment of the present invention, the color filter forming layer is formed by coating. First, as shown in FIG. 1A, for example, an alignment film 11 made of polyvinyl alcohol or the like is stacked on a glass substrate 10. Next, as shown in FIG.
A rubbing treatment is performed on the alignment film. This rubbing treatment is not necessarily required, but by performing the rubbing treatment, the orientation of the liquid crystal in the color filter forming layer can be improved.

Subsequently, as shown in FIG. 1- (C), the temperature is preferably 0 to 80 ° C., more preferably 15 to 25 ° C.
The above-mentioned liquid crystalline composition of the present invention is applied on the alignment film 11 preferably by any one of a bar coating method, a spin coating method, and a slit coating method to form a color filter forming layer 12. The thickness of the color filter forming layer 12 is preferably 1.5 to 4 μm. The liquid crystal composition (coating liquid) of the present invention has a high viscosity, is excellent in coatability, hardly causes defects even when dust is mixed in, and forms a color filter forming layer having a uniform thickness with high precision. Can be. Further, since the liquid crystalline composition of the present invention contains an air interface aligning agent, it is possible to control the pretilt angle of liquid crystal molecules without an aligning film on both sides, and it is not necessary to use an aligning film on one side. Simplification and cost reduction.

Thereafter, as shown in FIG. 2D, an exposure mask 14 having a plurality of regions having different light transmittances and a band-pass filter (not shown) above the alignment film 13.
Is arranged, and ultraviolet light is irradiated through the exposure mask 14 and the band pass filter to cause a photoreaction in the photoreactive chiral agent. The liquid crystalline composition does not need to exhibit liquid crystallinity until the step of irradiating the photoreactive chiral agent with light (including the time of isomerization), and the liquid crystalline composition is in a crystalline state or an amorphous state. There may be.

Next, as shown in FIG. 2E, a light source similar to that described above (without using a band-pass filter) is used for the color filter forming layer 12 and is different from the light irradiation described above. The pattern is fixed by irradiating ultraviolet rays with irradiation intensity. As a result, as shown in FIG.
The color filter forming layer 12 having blue (B), green (G), and red (R) reflection regions can be formed.

As described above, when the liquid crystalline composition of the present invention containing a photoreactive chiral agent is used, the rate of change of the twisting force of the helical structure of the liquid crystal with respect to the amount of light is large. Blue (B), green with wide color width and excellent color purity
A color filter composed of three primary colors (G) and red (R) can be obtained.

In the above-described production of the color filter, the color filter forming layer was formed by coating. However, the transfer layer having the above-mentioned transfer layer made of the liquid crystalline composition of the present invention was used. Is transferred onto a substrate (on an alignment film) to obtain the color filter of the present invention. In this case, due to the excellent applicability of the liquid crystalline composition of the present invention, the transfer layer can be formed with high precision by application.

[Liquid Crystal Display] Next, a liquid crystal display provided with the color filter of the present invention will be described. The liquid crystal display device of the present invention has at least a color filter, a liquid crystal layer, and a liquid crystal drive electrode between a support substrate and a counter substrate, and uses the color filter of the present invention as the color filter. The liquid crystal display device of the present invention is suitably a reflection type liquid crystal display device, but is not limited thereto.
A transmission type liquid crystal display device as described in Japanese Patent No. 230997 is also possible.

An example of the liquid crystal display device of the present invention will be described with reference to the drawings, but is not limited thereto. FIG.
1 shows an example of an active matrix type reflection type liquid crystal device. As shown in FIG. 3, the reflection type liquid crystal display device has a 1/4
Wave plate 42, transparent substrate 44, transparent common electrode 46, electrically drivable liquid crystal layer 48, transparent pixel electrode (display electrode)
50, a color filter 52 composed of a cholesteric polarizing element, a light absorbing layer 54, an active element 56 such as a THF (thin film transistor), a metal wiring 58 for electrically connecting the active element, and a support substrate 59 are sequentially arranged. ing. When an MIM is used as an active element, a stripe-shaped transparent electrode is formed as a scanning line on the transparent substrate 44 side. Note that a liquid crystal alignment film, a spacer, a sealant, and the like are usually used in a liquid crystal display device, but these are omitted in FIG.

Although a glass substrate is suitable for the transparent substrate 44 and the supporting substrate 59, a plastic substrate can be used instead of a glass substrate in order to obtain a liquid crystal display device that is lightweight and hard to break. Transparent electrode (common electrode 4
6, a pixel electrode 50, a scanning line, etc.) is preferably an ITO film.

The polarizing plate 40 and the 波長 wavelength plate 42 are
The polarizing plate 4 is arranged such that the light h1 incident from the observer side is emitted to the transparent substrate 44 side as clockwise or counterclockwise circularly polarized light.
The polarization plane of 0 and the slow axis of the quarter-wave plate 42 are arranged so as to keep an angle of about 45 degrees. In FIG. 3, they are arranged so as to be clockwise circularly polarized light. The quarter-wave plate used here is more preferably a broadband plate that generates a quarter-wave phase modulation over the entire wavelength of visible light.

The liquid crystal layer 48 has an optically isotropic phase when the drive voltage is in the OFF state, and has a retardation of 波長 wavelength in the ON state.

The transparent pixel electrode 50 for applying a voltage to the liquid crystal layer 48 includes an active element (TFT) 56 having a metal wiring 58 through a cholesteric polarizing element 52 and a through hole provided in the light absorbing layer 54. It is connected.

The cholesteric polarizing element 52 is divided into a red reflection area, a green reflection area, and a blue reflection area.
Each region has a helical pitch that selectively reflects the corresponding reflection color.

The light absorbing layer 54 is made of a cholesteric polarizing element 5
A device having a sufficient optical density so as to absorb all the light passing through 2 is disposed between the cholesteric polarizing element 52 and the active element (TFT) 56 and the metal wiring 58. With this arrangement, when no voltage is applied to the liquid crystal layer, circularly polarized light that passes through the color filter (for example, counterclockwise circularly polarized light as described below) is re-reflected by the wiring that connects the active elements. It is possible to prevent circularly polarized light (counterclockwise circularly polarized light) from passing through the color filter and reaching the viewer side. Although it is necessary to maintain electrical insulation between the active elements 56, it is preferable that the light absorption layer 54 have insulation so that the light absorption layer and the insulation layer can be combined. If the light absorbing layer 54 is not made to be insulating, it is necessary to provide an insulating layer between the light absorbing layer 54 and the active element 56 and the metal wiring 58. The light absorbing layer is preferably a layer that absorbs light having a wavelength in the visible region. For example, carbon black particles can be used as a pigment. Further, an insulating resin is preferably used as the binder polymer of the light absorbing layer, for example, a polyacetal resin, a polyamide resin,
An acrylic resin, a polycarbonate resin, and the like can be given.

Next, a display operation by the reflection type liquid crystal display device having the above configuration will be described with reference to FIG. In FIG. 3, the left side is a state where the driving voltage is OFF, and the right side is a state where the driving voltage is ON with respect to the center broken line.

As shown in FIG. 3, the light beam h1 incident from the observer side is converted into clockwise circularly polarized light by the polarizing plate 40 and the quarter-wave plate. When passing through the transparent substrate 44 and the transparent common electrode 46, this clockwise circularly polarized light enters the liquid crystal layer 48 in a state where no voltage is applied as clockwise circularly polarized light without any modulation. . Liquid crystal layer 48
Is in an optically isotropic state in the state where no voltage is applied, so that light is transmitted without being modulated, and then the light that has passed through the transparent pixel electrode 50 maintains the right circularly polarized state. As it is, it goes to the cholesteric polarizing element (color filter) 52. At this time, assuming that the helical direction and pitch of the cholesteric polarizing element 52 are determined so as to exhibit selective reflection in the red wavelength region, for example, of clockwise circularly polarized light, the incident right circularly polarized light h1 The light h2 of a color other than red passes through the cholesteric polarizing element 52, reaches the light absorbing layer 54, and is absorbed.

On the other hand, of the incident right circularly polarized light, red light cannot pass through the cholesteric polarizing element 52, is reflected as clockwise circularly polarized light h3, and travels toward the observer. The reflected red right circularly polarized light h3 reaches the quarter-wave plate 42 without any modulation for the above-described reason,
By the action of the quarter-wave plate 42 and the polarizing plate 40, the polarization axis is observed as linearly polarized light parallel to the polarization plane of the polarizing plate 40.

When a voltage is applied to the liquid crystal layer 48, the incident light h4 enters the liquid crystal layer 48 as clockwise circularly polarized light in the same manner as described above. When the voltage is applied, the liquid crystal layer 48 has a half-wave retardation,
The right-handed circularly polarized light is modulated to the left-handed circularly polarized light to form a liquid crystal layer 4.
8, the light passes through all the cholesteric modulation elements 52 that exhibit selective reflection only for clockwise circularly polarized light. Since all the transmitted light is absorbed by the light absorbing layer 54, no light is reflected to the observer as a result.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 shows an example of a simple matrix type reflection type liquid crystal display device. As shown in FIG. 4, the reflection type liquid crystal display element has a 波長 wavelength plate 62, a transparent substrate 64, a transparent scanning electrode 66 below the polarizing plate 60, and In this configuration, a drivable liquid crystal layer 68, a transparent signal electrode 70, a color filter 72 composed of a cholesteric polarizing element, a transparent support substrate 74, and a light absorbing layer 76 are sequentially arranged.

The transparent substrate 64, the transparent support substrate 74, the transparent (scanning / signal) electrodes 66 and 70, the polarizing plate 60, 1/4
The wave plate 62, the liquid crystal layer 68, and the color filter 72
The same ones as in FIG. 1 are used and function similarly.

A transparent signal electrode 70 for applying a voltage to the liquid crystal layer 68 is disposed between the color filter 72 composed of a cholesteric polarizing element and the liquid crystal layer 68.

The light absorbing layer 76 has a sufficient optical density so as to absorb all the light transmitted through the cholesteric polarizing element 72 and the transparent support substrate 74. It is arranged on the surface opposite to 72.

In the liquid crystal display device shown in FIG. 4, the light ray h1 when no voltage is applied to the liquid crystal layer and the light ray h4 when voltage is applied are reflected or reflected similarly to the liquid crystal display device in FIG. Absorbed, h1 is reflected as h3 by the color filter 72 toward the observer, while h4 is transmitted through the color filter and passes through the transparent substrate 74.
All light is absorbed by the light absorbing layer 76 and is not reflected toward the observer.

[0082]

EXAMPLES (1) Liquid crystalline composition First, compound a (polymerizable liquid crystal compound) shown below.
2 parts by mass, 2.2 parts by mass of compound b (chiral agent), 0.6 parts by mass of compound c (polymerization initiator), and 0.04 parts by mass of compound d (air interface aligning agent) were mixed with cyclohexane 80 as a solvent.
The solution was dissolved in parts by mass to prepare a coating solution.

[0083]

Embedded image

(2) Color Filter A polyimide alignment film (LX-1400, manufactured by Hitachi Chemical DuPont) is applied on a glass substrate by a spin coater, and dried in an oven at 100 ° C. for 5 minutes.
It was baked in an oven at 50 ° C. for 1 hour to form an alignment film.
Further, the surface of the film was subjected to an orientation treatment by a rubbing treatment to produce a glass substrate with an orientation film.

On the alignment film of the glass substrate provided with the alignment film,
The liquid crystal composition (temperature: 80 ° C.) of the above (1) is applied by a spin coater so that the applied layer becomes approximately 2 μm,
This was dried in an oven at 100 ° C. for 2 minutes to form a color filter forming layer. Next, this was placed on a hot plate at 100 ° C. so that the surface of the glass substrate was in contact therewith, and held for 5 minutes to develop a color filter forming layer. Further, on the color filter forming layer, the transmittance is different in three stages (0%, 46%, 92%), and the respective regions are arranged corresponding to the red pixel, the green pixel, and the blue pixel. An ultra-high pressure mercury lamp was arranged via a photomask and a band-pass filter having a center at 365 nm, and irradiation was performed with the ultra-high pressure mercury lamp through the photomask and the band-pass filter to perform patterning. The irradiation energy at this time is 600 mJ / cm ² for the blue pixel,
The irradiation intensity was 30 mW / cm ² .

Next, the photomask and the bandpass filter were removed, and the irradiation energy was 500 mJ / cm ² by the same ultra-high pressure mercury lamp as above while blowing nitrogen gas.
Then, the entire surface was exposed and polymerized and cured. Further, in order to accelerate the curing of the color filter forming layer, the color filter was baked in an oven at 220 ° C. for 20 minutes to obtain a color filter with high color purity in which red, green, and blue pixel patterns were formed. The obtained color filter was formed into a uniform film thickness of about 2 μm as described above because the liquid crystalline composition was excellent in coatability, and a color filter having a uniform selective reflection wavelength and sufficient reflectance was manufactured. Was done.

(3) Liquid Crystal Display Next, a liquid crystal display having a structure as shown in FIG. 4 was manufactured. (1) Preparation of transparent support substrate A borosilicate glass substrate having a thickness of 1.1 mm was washed and dried. (2) light absorbing layer, color filter layer on transparent support substrate,
Formation of Transparent Signal Electrode and Alignment Film To the transparent support substrate prepared in the above (1), a solution for a light absorbing layer containing carbon black and an insulating resin (polyvinyl butyral) (adding 30% by mass of carbon black to the insulating resin) ) Was applied and dried by spin coating so that the dry thickness was 2 μm.

The color filter was provided on the surface of the transparent support substrate opposite to the light absorbing layer. Next, an ITO film having a thickness of 0.1 μm was formed on the color filter layer by a sputtering method, and then a pattern was formed by a conventional photolithography method to form a stripe-shaped transparent signal electrode. A polyimide alignment film (LX-140) is formed on the transparent signal electrode.
0, manufactured by Hitachi Chemical DuPont Co., Ltd.) A coating solution was applied by a spin coater, dried in an oven at 100 ° C. for 5 minutes, and baked in an oven at 250 ° C. for 1 hour to form an alignment film. Was subjected to an alignment treatment by a rubbing treatment. (3) Preparation of Transparent Substrate (Counter Substrate) An ITO film was formed on a counter glass substrate having a thickness of 1.1 mm by a sputtering method to a thickness of 0.1 μm by a sputtering method. A transparent scanning electrode was formed, and an alignment process was performed in the same manner as the above-described alignment process.

(4) Manufacture of Liquid Crystal Cell After the alignment treatment surface side of the transparent support substrate provided with the color filters and the like and the orientation treatment surface side of the counter substrate were bonded with a space of 2 μm, liquid crystal was injected. . The liquid crystal used had a homeotropic alignment when the voltage was ON, and the retardation was halved when the voltage was OFF. A quarter wavelength plate (Sumitomo Chemical Co., Ltd.)
Sumikalite) and polarizing plates (Sumitomo Chemical Co., Ltd.)
SH-1832AW) was applied via an adhesive. The liquid crystal display device manufactured in this manner uses a color filter having a uniform film thickness of about 2 μm as the coating layer manufactured as described above, so that a sufficiently high reflectance and a bright display can be obtained. Liquid crystal display device was obtained.

[0090]

The liquid crystalline composition of the present invention has a viscosity of 1 to 1
Since it is 00 cP, a uniform and thick film can be formed by coating, and coating defects are unlikely to occur even when dust is mixed. In addition, since an air interface alignment agent is contained, the pretilt angle of liquid crystal molecules can be controlled in the production of a color filter, so that one alignment film can be omitted, and the production can be simplified and the cost can be reduced. Further, when a color filter is manufactured using the liquid crystalline composition, a color filter having a uniform selective reflection wavelength and a sufficient reflectance can be obtained.
A liquid crystal display device incorporating such a color filter can provide a bright display without using any illumination means.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a part of a process of manufacturing a liquid crystal color filter of the present invention.

FIG. 2 is a schematic view showing a part of a process of manufacturing a liquid crystal color filter of the present invention.

FIG. 3 is a conceptual diagram showing an example of an active matrix type liquid crystal display device of the present invention. The left side of the dashed line indicates the reflection or absorption of circularly polarized light in the voltage OFF state, and the right side thereof indicates the voltage ON state.

FIG. 4 is a conceptual diagram showing an example of a simple matrix type liquid crystal display device of the present invention.
The right side of the state shows the reflection or absorption of the circularly polarized light in the voltage ON state, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 11 Alignment film 12 Color filter formation layer 14 Exposure mask 40, 60 Polarizer 42, 62 1/2 wavelength plate 44, 64 Transparent substrate 46 Transparent common electrode 48, 68 Liquid crystal layer 50 Transparent pixel electrode 52, 72 Color filter 54 , 76 light absorbing layer 56 TFT element 58 metal wiring 59, 74 support substrate 66 transparent scanning electrode 70 transparent signal electrode

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 500 G02F 1/1335 500 520 520 F Term (Reference) 2H048 AA01 AA06 AA12 AA18 BA64 BB02 BB42 2H049 BA03 BA05 BA07 BA42 BA43 BC05 BC22 2H091 FA02Y FA14Y FB02 FC23 GA06 LA16 4J002 BG071 CH021 CK021 CP051 CP211 EU187 EV267 FD200 FD206 FD207 GP00

Claims (6)

[Claims] 1. A liquid crystalline composition comprising at least a liquid crystalline compound having at least one polymerizable group, a chiral agent, a polymerization initiator, an air interface aligning agent and a solvent, and having a viscosity of 1 to 100 cP. Composition. 2. The liquid crystalline composition according to claim 1, having a surface tension of 50 mN / m or less. 3. The liquid crystalline composition according to claim 1, wherein the chiral agent is a photoreactive chiral agent. 4. Used in a liquid crystal display device, at least
A color filter manufacturing method comprising the steps of forming an alignment film on a substrate, providing a color filter forming layer made of a liquid crystalline composition on the alignment film, and irradiating the color filter forming layer with ultraviolet light. A color filter, wherein the liquid crystalline composition is the liquid crystalline composition according to any one of claims 1 to 3. 5. The color filter according to claim 4, wherein the color filter forming layer is formed by applying any one of a bar coating method, a spin coating method, and a slit coating method. 6. A liquid crystal display device comprising the color filter according to claim 4.