JP4765738B2 - Color filter, manufacturing method thereof, and liquid crystal display - Google Patents

Description

  The present invention relates to a color filter, a manufacturing method thereof, and a liquid crystal display, and more particularly, to a color filter including a phase difference control layer for improving a viewing angle.

  Various types of liquid crystal displays have been put into practical use. In these liquid crystal displays, a retardation control layer is often used in combination with a linear polarizing plate. For example, a circularly polarizing plate in which a linearly polarizing plate and a 1/4 wavelength phase difference plate, or a 1/2 wavelength phase difference plate, a 1/4 wavelength phase difference plate, and a linearly polarizing plate are combined is provided on the observation side of the liquid crystal display. Thus, reflection of external light is prevented and display contrast can be improved.

  In addition, a circularly polarizing plate or an elliptically polarizing plate is used in a reflective liquid crystal display or a transflective liquid crystal display in order to use an optical shutter effect of liquid crystal molecules.

  Furthermore, a phase difference plate is also used to improve color compensation and viewing angle characteristics of a super twisted nematic mode liquid crystal display. Particularly in recent years, in a vertical alignment mode liquid crystal display capable of high-contrast display, a retardation film (negative C plate) having an optical axis perpendicular to the substrate and having negative birefringence anisotropy, and an optical axis on the substrate. There is an example in which a phase difference film having a positive birefringence anisotropy (positive A plate) is used in combination (for example, see Patent Document 1).

  For retardation control in these, a retardation control film obtained by stretching a polycarbonate film or the like or a retardation control film obtained by applying a liquid crystal material having birefringence anisotropy to a triacetyl cellulose film or the like is usually used.

  However, in the above-described conventional retardation film, the retardation is uniform in the plane, and is not set to the optimum retardation for each actually displayed pixel, and the optimum retardation compensation is not necessarily performed. I don't mean.

  One of the reasons is that the retardation and refractive index of the liquid crystal itself has wavelength dependency of the transmitted light, so that the phase difference film depends on the pattern color of each color constituting the color filter (actually the wavelength of the transmitted light). This is because the required retardation is different.

  On the other hand, an attempt has been made to perform retardation compensation more optimally by controlling retardation according to the wavelength of transmitted light (see, for example, Patent Document 2).

However, in reality, despite such attempts, when viewing a black display with viewing angle compensation from an oblique direction, there is a problem that it appears reddish purple due to red and blue leakage light. It was.
JP-A-10-153802 JP 2005-148118 A

  The present invention has been made under the circumstances as described above, and provides a method for efficiently and highly producing a color filter that exhibits excellent characteristics in viewing angle expansion from an oblique direction by optimal phase difference compensation in each pixel. The purpose is to provide. Another object of the present invention is to provide a color filter manufactured by such a method and a liquid crystal display including such a color filter.

  In order to solve the above problems, the present inventors have conducted extensive research and as a result, the retardation of the color filter layer of each color pixel pattern of red, green and blue is different, red and blue indicate positive retardation, green Was found to indicate negative retardation. Usually, since optical design is performed centering on green, if the retardations of the red and blue color filter layers and the green color filter layer are significantly different from each other in positive and negative, red and blue leakage light is generated as described above. The present invention has been made based on such findings.

  The first aspect of the present invention includes a step of forming partition walls on a substrate, a step of forming a plurality of colored pixel patterns having a predetermined retardation between the partition walls by an ink jet method, and an orientation on the colored pixel patterns. A step of forming a processed alignment film, and a step of forming a liquid crystal retardation layer on the alignment film by a photolithography method corresponding to the retardation of each of the plurality of colored pixel patterns. A method for producing a color filter is provided.

  In such a color filter manufacturing method, the plurality of colored pixel patterns include a red pixel pattern, a blue pixel pattern, and a green pixel pattern, and the red pixel pattern and the blue pixel pattern have positive retardation, and the green pixel pattern Can have a negative retardation.

  The liquid crystal retardation layer can be composed of a liquid crystal selected from the group consisting of a polymerizable nematic liquid crystal, a polymerizable cholesteric liquid crystal, and a homeotropically aligned polymerizable liquid crystal.

  Further, the liquid crystal retardation layer may include a plurality of liquid crystal retardation regions corresponding to the plurality of colored pixel patterns, and each of the liquid crystal retardation regions may have a different retardation for each of the plurality of colored pixel patterns. .

  In this case, it is desirable that the retardations of the plurality of liquid crystal retardation regions have retardations according to the wavelength range of light passing therethrough. In addition, it is desirable that the plurality of liquid crystal retardation regions have a retardation that corrects the retardation of the plurality of colored pixel patterns.

  In the color filter manufacturing method described above, the retardation of the plurality of liquid crystal retardation regions is opposite in sign to the retardation of the colored pixel pattern and can have substantially the same absolute value. In this case, the plurality of liquid crystal retardation regions can be constituted by a crosslinked cured product of a polymerizable liquid crystal composition that differs for each of the plurality of colored pixel patterns.

  Moreover, the sum total of the retardation of a several colored pixel pattern and the retardation of the some liquid crystal phase difference area | region corresponding to it can be made substantially the same for every pixel. In this case, a plurality of liquid crystal retardation regions can be constituted by cross-linked cured products of the same polymerizable liquid crystal composition and have different film thicknesses.

  According to a second aspect of the present invention, there is provided a color filter manufactured by the method described above.

  According to a third aspect of the present invention, there is provided a liquid crystal display comprising the color filter.

  According to the present invention, since a plurality of colored pixel patterns are formed by the ink jet method, it is possible to reduce the environmental burden and significantly reduce the cost. In addition, by adjusting the retardation of the liquid crystal retardation layer in accordance with the retardation of each colored pixel pattern, there is no variation in the polarization state of the light passing through the display area of each pixel. There is provided a color filter exhibiting excellent magnification characteristics.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a sectional view showing a color filter according to the first embodiment of the present invention. In FIG. 1, a partition black matrix 2 made of a light-shielding material is provided at a position corresponding to a non-pixel portion on a transparent substrate, for example, a glass substrate 1. Each of the red pixel pattern 3 (R), the green pixel pattern 3 (G), and the blue pixel pattern 3 (B), each of which is light transmissive, in each opening of the partition wall black matrix 2 corresponding to the pixel portion. A color filter layer configured by arranging colored pixel patterns is laminated.

  In addition, an alignment film 4 is laminated on the color filter layer in the opening, and further, on the alignment film 4 in the opening of the partition wall black matrix 2, for each pixel, a position made of a cured product of polymerizable liquid crystal. A phase difference control layer composed of the phase difference control regions 5 (R), 5 (G), and 5 (B) is laminated, and these constitute a color filter.

  In the present specification, the polymerizable liquid crystal composition refers to a liquid crystal state that is fixed at room temperature. For example, a liquid crystal monomer having a polymerizable group in its molecular structure is cross-linked to form an optical before cross-linking. Hardened while maintaining anisotropy, or has a glass transition temperature, shows a liquid crystal phase when heated above the glass transition temperature, and then freezes the liquid crystal structure by cooling below the glass transition temperature A high-molecular liquid crystal capable of

  In addition, each character of R, G, and B shall represent red, green, and blue in order.

  Each of the colored pixel patterns 3 (R), 3 (G), and 3 (B) has a different retardation for each light of red, green, and blue that passes through each pattern, as shown in FIG. . This retardation shows various values depending on the material, thickness, and processing method of the retardation, but the present inventors show that the red pixel pattern 3 (R) and the blue pixel pattern 3 (B) have positive retardation. The green pixel pattern 3 (G) was found to have negative retardation.

  Specifically, the retardation in the thickness direction of the blue pixel pattern 3 (B) is 0.1 nm to 100 nm, the retardation in the thickness direction of the green pixel pattern 3 (G) is −100 nm to −0.1 nm, and red. The retardation in the thickness direction of the pixel pattern 3 (R) is 0.1 nm to 100 nm.

  In order to compensate for the retardation of these colored pixel patterns 3 (R), 3 (G), and 3 (B), the retardation of each phase difference control region is an absolute value that is opposite in sign to the retardation of the colored pixel pattern. Are substantially the same, the retardation of the phase difference control region 5 (B) is -100 nm to -0.1 nm, and the retardation of the phase difference control region 1 (G) is 0.1 nm to 100 nm. The retardation of the phase difference control region 5 (R) is preferably −100 nm to −0.1 nm.

  The liquid crystal materials constituting the liquid crystal retardation regions 5 (R), 5 (G), and 5 (B) are nematic liquid crystal material, cholesteric liquid crystal material, or homeo so as to have retardation according to the wavelength range of light passing through each layer. It is preferable to appropriately select a tropic-aligned polymerizable liquid crystal material.

  That is, the liquid crystal material constituting the liquid crystal retardation regions 5 (R), 5 (G), and 5 (B) may be any material that has a function of giving a phase difference to light incident at a certain incident angle. Not only the nematic liquid crystal described above, but also any liquid crystal material such as a chiral nematic liquid crystal (a nematic liquid crystal with a chiral agent added) can be used.

  The nematic liquid crystal preferably has a polymerizable group. The chiral agent also preferably has a polymerizable group. As for the chiral nematic liquid crystal, it is preferable to use nematic liquid crystals alone or as a mixture of two or more nematic liquid crystals as necessary.

  Next, with reference to FIG. 3, the manufacturing method of the color filter with a phase difference control layer shown in FIG. 1 will be described.

  First, as shown in FIG. 3A, a black matrix 2 for improving contrast is provided on a transparent substrate 1.

  As the transparent substrate 1, a known transparent substrate material such as a glass substrate, a quartz substrate, or a plastic substrate can be used. Among them, the glass substrate is excellent in transparency, strength, heat resistance, and weather resistance.

  The black matrix 2 can be formed using a known method. For example, a method of forming a metal or metal oxide thin film on a substrate by a method such as sputtering, and patterning it by a method such as etching; a colorant such as a pigment or a dye in the photosensitive resin composition Are formed as a photosensitive resin composition layer on a substrate and formed by a photolithography method; a method in which a black pigment and a thermosetting resin are dissolved in a solvent and formed by a printing method, and the like. The black matrix 2 desirably contains an ink repellent agent to prevent color mixing. Color mixing occurs when color ink enters the color ink of adjacent pixels.

  Examples of the ink repellent agent include silicone materials and fluorine materials. Specifically, a silicone resin or silicone rubber having an organosilicone or alkylfluoro group in the main chain or side chain and containing a siloxane component, in addition to vinylidene fluoride, vinyl fluoride, ethylene trifluoride, etc. Fluorine resins such as these copolymers can be used. Also, the ink repellent agent bleeds out during the heating process, the ink repellent agent adheres to the transparent substrate, and color loss may occur when filling the color ink. To prevent this, the ink repellent agent As the agent, a fluorine-containing compound is preferably used. In order to prevent bleeding out, it is preferable to use an oligomer compound rather than a low molecular compound.

  Next, as shown in FIG. 3B, red (R), green (G), and blue (B) colored pixel patterns 3 (R), 3 (G), 3 ( B) is formed. In the case of a liquid crystal display, a transparent conductive layer and an alignment film layer are further laminated in order, and are opposed to a counter substrate on which an electrode such as a thin film transistor is formed, for example, and an LCD is formed through the liquid crystal layer. Below, the transparent substrate 1, the black matrix 2, and the red, green, and blue colored pixel patterns 3 (R), 3 (G), and 3 (B) are combined to form a color filter substrate.

  Usually, a pixel pattern composed of three primary colors of a red pixel pattern 3 (R), a green pixel pattern 3 (G), and a blue pixel pattern 3 (B) is arranged in a desired shape in the opening of the black matrix 2.

  In the present embodiment, color ink is formed in a pattern by an ink jet apparatus, and then colored pixel patterns 3 (R), 3 (G), and 3 (B) are formed through a heating process described later.

  As an apparatus used for inkjet, there are a piezo conversion method and a heat conversion method depending on the ink ejection method, but it is desirable to use a piezo conversion method apparatus. In addition, the ink atomization frequency in the ink jet apparatus is desirably about 5 to 100 KHz. The nozzle diameter in the ink jet apparatus is desirably about 5 to 80 μm. In addition, it is preferable to use an inkjet apparatus in which a plurality of heads are arranged and about 60 to 500 nozzles are incorporated in one head.

  As the colorant of the color ink, pigments, dyes and the like can be used. In the present invention, it is preferable to use a pigment having excellent weather resistance. Specific examples of the coloring agent include Pigment Red 9, 19, 38, 43, 97, 122, 123, 144, 149, 166, 168, 177, 179, 180, 192, 215, 216, 208, 216, 217, 220, 223, 224, 226, 227, 228, 240, 254, Pigment Blue 15, 15: 6, 16, 22, 29, 60, 64, Pigment Green 7, 36, Pigment Yellow 20, 24, 86, 81, 83 93, 108, 109, 110, 117, 125, 137, 138, 139, 147, 148, 150, 153, 154, 166, 168, 185, Pigment Orange 36, Pigment Violet 23, and the like. Furthermore, in order to obtain a desired hue, two or more kinds of materials can be mixed and used.

  The thermosetting resin used for the color ink is appropriately selected from materials used for manufacturing a known color filter substrate in relation to the pigment. Specifically, casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin, or the like can be used. In particular, when manufacturing a color filter that requires heat resistance and light resistance, it is preferable to use an acrylic resin.

  The solvent used for the color ink is selected depending on the printability of the ink jet apparatus, and it is particularly preferable to use a material having a surface tension range of less than 35 mN / m and a boiling point of 130 ° C. or higher. When the surface tension is 35 mN / m or more, the dot shape stability during ink jet ejection is adversely affected. Further, when the boiling point is lower than 130 ° C., the drying property near the nozzle is increased. As a result, there is a possibility of causing a defect such as nozzle clogging, which is not preferable.

  The solvent is appropriately selected depending on the thermosetting temperature of the thermosetting resin of the color ink. When a solvent having a remarkably low boiling point compared to the thermosetting temperature of the thermosetting resin is used, there is a concern that the colored layer has a concave shape as described above. As a solvent satisfying these conditions, specifically, diethylene glycol-n-butyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, tripropylene glycol methyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n- Examples thereof include butyl ether, tripropylene glycol-n-butyl ether, and propylene glycol phenyl ether.

  In addition, in order to further increase the boiling point of the solvent, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-methoxyethyl acetate, 2 -Ethoxyethyl ether, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate, 2-phenoxyethanol Diethylene glycol dimethyl ether or the like can be used. Moreover, what was prepared by mixing 2 or more types of solvent so that it may meet the said conditions as needed can be used.

  The color ink dispersant is used to improve the dispersion of the pigment in the resin. As the dispersant, an ionic or nonionic surfactant or the like can be used. Specific examples include sodium alkylbenzene sulfonate, poly fatty acid salts, fatty acid salt alkyl phosphates, tetraalkyl ammonium salts, polyoxyethylene alkyl ethers, and other organic pigment derivatives and polyesters. One type of dispersant may be used alone, or two or more types of dispersants may be mixed and used.

  Next, the alignment film 4 is laminated on the colored pixel patterns 3 (R), 3 (G), and 3 (B). As the material constituting the alignment film 4, polyimide, polyamide, polyvinyl alcohol, or the like is usually used. In the present invention, the alignment film 4 is formed by applying by spin coating, drying and baking. By subjecting such an alignment film 4 to a rubbing treatment, alignment ability for liquid crystal is imparted. As the rubbing treatment, a rubbing cloth selected from materials such as rayon, cotton, polyamide and the like is applied to a metal roll, and the roll is rotated while in contact with the alignment film 4 formed on the color filter substrate. A method of rubbing the alignment film 4 with a rubbing cloth is usually employed by transporting the color filter substrate 1 with the alignment film 4 while being fixed.

  Next, a different polymerizable liquid crystal composition for each pixel is formed on the alignment film 4 by photolithography. For film formation of different polymerizable liquid crystal compositions, it is necessary to repeat photolithography a plurality of times. As the liquid crystal composition, a nematic liquid crystal material, a cholesteric liquid crystal material, or a polymerizable liquid crystal material having homeotropic alignment is appropriately selected so as to have retardation corresponding to the wavelength range of light passing through each layer.

  The patterning step by the photolithography method includes a step of forming a liquid crystal composition layer on a substrate, an exposure step, and a development step of removing an unexposed portion that becomes an unnecessary portion.

  Examples of the method for providing the liquid crystal composition layer include known methods such as a bar coater, an applicator, a wire bar, a spin coater, a roll coater, a slit coater, a curtain coater, a die coater, and a comma coater. As an exposure method, for example, a proximity method using a photomask in which a light-shielding portion is formed by ultraviolet light using an ultrahigh pressure mercury lamp or a semiconductor laser as a light source. Alternatively, a mirror projection method using an optical system using convex and concave mirrors, a division exposure method in which a projection lens is provided, and an irradiation surface is divided may be used. As the developer, an organic solvent system or an alkaline aqueous solution system is generally used, but an inorganic alkali system is preferable from the viewpoint of ensuring environmental safety.

Next, the liquid crystal layer applied by a printing method on the alignment film 4 is irradiated with ultraviolet rays having a predetermined irradiation amount, and the liquid crystal composition is three-dimensionally crosslinked and cured. In addition, when the ultraviolet rays irradiated to the liquid crystal layer cure the liquid crystal, it is preferable to add a photopolymerization initiator in the liquid crystal material. The dose of ultraviolet rays, the presence or amount of the photopolymerization initiator, or varies depending on the radiation type and intensity, is preferably about the range of, for example, ^{1mJ / cm 2 ~10000mJ / cm 2} . Moreover, it is preferable that the atmosphere which irradiates an ultraviolet-ray is inert gas atmosphere, such as nitrogen. By irradiating ultraviolet rays in such an atmosphere, the liquid crystal composition can be cured without being affected by oxygen, and the optical characteristics of the liquid crystal layer can be stabilized. Furthermore, it is preferable to uniformly control the temperature of the atmosphere in which the ultraviolet rays are irradiated at a temperature higher than room temperature. Thereby, the polymerization of the liquid crystal material at the time of ultraviolet irradiation can be promoted, and the optical characteristics of the liquid crystal layer can be stabilized.

  Here, “three-dimensional crosslinking” means that polymerization monomers, oligomers, polymers, or the like are polymerized three-dimensionally to form a network (network) structure. In such a state, the state of the liquid crystal material of the liquid crystal layer can be optically fixed, and a film-like film that is easy to handle as an optical film and stable at room temperature can be obtained.

  Finally, the liquid crystal layer is baked to a predetermined temperature and re-cured to stabilize the optical characteristics of the liquid crystal layer. At this time, the liquid crystal layer can be heated and cured at a high temperature, but the temperature is preferably 100 ° C. to 150 ° C. In this case, the optical characteristics of the liquid crystal layer can be further stabilized.

  As a result, finally, as shown in FIG. 3 (d), a liquid crystal composed of liquid crystal retardation regions 5 (R), 5 (G), and 5 (B) having retardations corresponding to the display regions of the respective colors of the pixels. A retardation layer is formed, and a color filter with a liquid crystal retardation layer is completed.

  As described above, as the liquid crystal composition that is different for each pixel, the liquid crystal composition having a retardation of −100 nm to −0.1 nm is used for the phase difference control region 5 (R). A liquid crystal composition having a retardation of 0.1 nm to 100 nm is selected for 5 (G), and a liquid crystal composition having a retardation of −100 nm to −0.1 nm is selected for the phase difference control region 5 (B). To do.

  As described above, according to the first embodiment, the liquid crystal retardation regions 5 (R), 5 (G), and 5 (B) are adjusted so as to have retardation corresponding to the wavelength region of light. Therefore, there is no variation in the polarization state of light passing through the display area of each color of the pixel. Furthermore, since the display is black with the viewing angle compensated from the oblique direction, when viewed from the oblique direction, the color shift can be reduced and the neutral black can be reproduced, and the display characteristics are excellent. be able to.

  FIG. 4 is a sectional view showing a color filter according to the second embodiment of the present invention. In FIG. 4, a black matrix 2 made of a light-shielding material is provided at a position corresponding to a non-pixel portion on the transparent substrate 1, and light is transmitted through each opening of the black matrix 2 corresponding to the pixel portion. The color filter layer formed by arranging each colored pixel pattern of the red pixel pattern 3 (R), the green pixel pattern 3 (G), and the blue pixel pattern 3 (B), which is a color, is laminated, and the color in the opening The alignment film 4 is laminated on the filter layer in the same manner as the color filter according to the embodiment shown in FIG.

  The color filter according to the present embodiment is different from the color filter according to the embodiment shown in FIG. 1 in that, in the color filter according to the embodiment shown in FIG. While the liquid crystal retardation regions 5 (R), 5 (G), and 5 (B) having the retardation corresponding to the wavelength range of light passing through each layer are formed by laminating the composition, this embodiment In the color filter according to the above, the same polymerizable liquid crystal composition is laminated on the alignment film 4 for all pixels, and the liquid crystal positions having different film thicknesses so as to have retardation corresponding to the wavelength range of light passing through each layer. The phase difference regions 15 (R), 15 (G), and 15 (B) are formed.

  In this case, the retardation in the thickness direction of the liquid crystal retardation regions 15 (R), 15 (G), and 15 (B) and the thickness direction of each colored pixel pattern 3 (R), 3 (G), and 3 (B) It is preferable that the sum of retardation is equal to each other for each pixel. The specific value differs according to the value of retardation in the thickness direction of each colored pixel pattern 3 (R), 3 (G), 3 (B).

  For example, the retardation in the thickness direction of the blue pixel pattern 3 (B) was 5 nm, the retardation in the thickness direction of the green pixel pattern 3 (G) was −40 nm, and the retardation in the thickness direction of the red pixel pattern 3 (R) was 10 nm. In this case, for example, if the retardation of the liquid crystal retardation layer 15 (B) is 15 nm, the retardation of the liquid crystal retardation layer 15 (G) is 60 nm, and the retardation of the liquid crystal retardation layer 15 (R) is 10 nm, each colored pixel The sum of the retardation in the thickness direction of the patterns 5 (R), 1 (G), and 5 (B) and the retardation in the thickness direction of the liquid crystal retardation layers 15 (R), 15 (G), and 15 (B) is 20 nm. And become equal to each other.

  Retardation of each liquid crystal phase difference layer 15 (R), 15 (G), 15 (B) is represented by the product of the refractive index anisotropy Δn in the thickness direction and the film thickness d. Since Δn is constant for the same polymerizable liquid crystal composition, the retardation of the liquid crystal retardation regions 15 (R), 15 (G), and 15 (B) can be controlled by the film thickness.

  A retardation in the thickness direction of the liquid crystal retardation regions 15 (R), 15 (G), and 15 (B) and a retardation in the thickness direction of each colored pixel pattern 3 (R), 3 (G), and 3 (B). The total value is not particularly limited as long as it is equal to each other for each pixel. However, the absolute value is preferably closer to 0 in order not to significantly impair the characteristics of the final liquid crystal display. Therefore, in the above-described example, for example, the retardation of the liquid crystal retardation region 15 (B) is 5 nm, the retardation of the liquid crystal retardation region 15 (G) is 50 nm, and the retardation of the liquid crystal retardation region 15 (R) is 0 nm. For example, the sum of the retardation in the thickness direction of each of the liquid crystal retardation regions 15 (R), 15 (G), and 15 (B) and the retardation in the thickness direction of each colored pixel pattern is equal to each other at 10 nm, which is more preferable. . At this time, since the retardation of the liquid crystal retardation region 15 (R) is 0 nm, the thickness of the liquid crystal retardation region 15 (R) is 0, which means that the liquid crystal retardation region 15 (R) is not provided. It becomes.

  Thus, according to the retardation value in the thickness direction of each colored pixel pattern, the film of each liquid crystal retardation region is such that the sum of the retardation in the thickness direction of each liquid crystal retardation region is equal to each other for each pixel. By controlling the thickness, it is possible to correct the optimum retardation.

  The color filter according to the second embodiment shown in FIG. 4 described above can be manufactured in the same manner as the manufacturing process shown in FIG. However, by repeating the film formation of the liquid crystal composition on the alignment film 4 by photolithography a plurality of times, the film thickness is changed for each pixel so that a liquid crystal layer having a film thickness corresponding to the required retardation is formed. Need to be done. Naturally, the liquid crystal composition is not formed on the pixel portion that does not require the liquid crystal retardation region.

Examples Hereinafter, more specific examples of the embodiment described above will be shown, but the present invention is not limited to these examples. Further, since the material used in the present invention is extremely sensitive to light, it is necessary to prevent exposure to unnecessary light such as natural light, and all operations were performed under a yellow or red light.

Example 1
<Formation of liquid crystal retardation layer>
A liquid crystal composition (A) was prepared by dissolving 100 parts by weight of a nematic liquid crystal having a polymerizable group and 5 parts by weight of a photoinitiator in 420 parts of toluene. This liquid crystal composition (A) was mixed with 9 parts by weight of a chiral agent to obtain a liquid crystal composition (B). The nematic liquid crystal in the liquid crystal composition (A) was replaced with a nematic liquid crystal having a higher birefringence, and a liquid crystal composition (C) was prepared at the same mixing ratio.

  First, a polyimide film was formed on a glass substrate by spin coating, a baking process was performed at 230 ° C. for 1 hour, and then a rubbing treatment was performed in a certain direction with a rubbing cloth to form an alignment film.

Next, the liquid crystal composition (B) was applied on the substrate subjected to the alignment treatment by a spin method to form a liquid crystal layer. The film thickness of the liquid crystal layer after heating at 60 ° C. for 1 minute was 0.7 μm. Next, the liquid layer was exposed with an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. In addition, the exposure process was implemented in nitrogen atmosphere so that superposition | polymerization inhibition by the oxygen in air | atmosphere might not arise.

  Furthermore, in order to stabilize the liquid crystal layer, a retardation layer was formed by a heating process at 150 ° C. for 30 minutes. It was 40 nm when the retardation of the thickness direction of this phase difference layer was measured.

  Moreover, the polyimide used above was changed for vertical alignment, and the vertical alignment film was similarly formed on the glass substrate. At this time, the rubbing process is not performed.

Next, a liquid crystal layer was formed by applying the liquid crystal composition (A) and the liquid crystal composition (C) to the two glass substrates on which the vertical alignment films had been formed by a printing method. The film thickness after heating at 60 ° C. for 1 minute was 0.7 μm. Subsequently, the liquid crystal layer was exposed at an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. In addition, in this exposure process, it implemented in nitrogen atmosphere so that superposition | polymerization inhibition by the oxygen in air | atmosphere might not arise.

  Furthermore, in order to stabilize the liquid crystal layer, a retardation layer was formed by a heating process at 150 ° C. for 30 minutes.

  When the retardation in the thickness direction of the retardation layer was measured, it was -5 nm in the substrate in which the retardation layer was formed from the liquid crystal composition (A), and-in the substrate in which the retardation layer was formed from the liquid crystal composition (C). It was 20 nm.

<Production of color filter>
(Production of black matrix)
10 parts by weight of a polyimide precursor (Semicofine SP-510: manufactured by Toray Industries, Inc.), 7.5 parts by weight of carbon black, 130 parts by weight of NMP, 5 parts by weight of a dispersant (copper phthalocyanine derivative), 5 parts by weight of initiator A, and A black matrix composition was prepared by dispersing 0.1 part by weight of a perfluoroalkyl group-containing oligomer (FTX-720C: manufactured by Neos Co., Ltd.) for 3 hours while cooling with a bead mill disperser.

  This black matrix composition was applied onto an alkali-free glass substrate (product number 1737: manufactured by Corning) using a spin coater to form a coating film having a thickness of about 2.0 μm. Thereafter, after pre-baking at 100 ° C. for 20 minutes, after exposure and development processes, post-baking is performed at 230 ° C. for 60 minutes, and as shown in FIG. Black matrix 2 was formed.

  The contact angle with respect to the colored ink (surface tension 30 mN / m) at the top of the black matrix 2 formed in this way was measured and found to be 30 °, and the top of the black matrix was ink repellent with respect to the colored ink. Confirmed that there is.

(Preparation of color ink)
[Production of coloring material]
The following were used as the coloring agents for coloring the coloring material used for producing the color filter.

Red pigment: C.I. I. Pigment Red 254 (“Ilgar Forred B-CF” manufactured by Ciba Specialty Chemicals) and C.I. I. Pigment Red 177 (“Chromophthal Red A2B” manufactured by Ciba Specialty Chemicals)
Green pigment: C.I. I. Pigment Green 36 (“Lionol Green 6YK” manufactured by Toyo Ink) and C.I. I. Pigment Yellow 150 (Bayer's “Funcheon First Yellow Y-5688”)
Blue pigment: C.I. I. Pigment Blue 15 (“Rionol Blue ES” manufactured by Toyo Ink) C.I. I. Pigment Violet 23 (manufactured by BASF “Paliogen Violet 5890”)
Also, 20 parts of methacrylic acid, 10 parts of methyl methacrylate, 55 parts of butyl methacrylate and 15 parts of hydroxyethyl methacrylate are dissolved in 300 g of butyl lactate, and 0.75 part of azobisisobutylnitrile is added under a nitrogen atmosphere, and 5 parts at 70 ° C. An acrylic copolymer resin was prepared by reaction over time. The obtained acrylic copolymer resin was diluted with diethylene glycol monomethyl ether so as to have a resin concentration of 20% to obtain an acrylic varnish.

  Using the above pigments and acrylic varnish, red, green, and blue coloring materials were produced as follows.

-Red coloring material After uniformly stirring and mixing a mixture having the composition shown below, using a glass bead having a diameter of 1 mm, dispersing it with a sand mill for 5 hours, and then filtering with a 5 μm filter, a red pigment dispersion is produced. did.

Red pigment: C.I. I. Pigment Red 254 18 parts by weight Red pigment: C.I. I. Pigment Red 177 2 parts by weight Acrylic varnish: (solid content 20%) 108 parts by weight Then, the mixture having the composition shown below was stirred and mixed uniformly, and then filtered through a 5 μm filter to obtain a red colored material. It was.

128 parts by weight of the dispersion, 50 parts by weight of diethylene glycol monomethyl ether, 30 parts by weight of tetraethylene glycol dimethyl ether, and a green coloring material. The green coloring material was prepared by the same method as that for the red coloring material.

Green pigment: C.I. I. Pigment Green 36 16 parts by weight Yellow pigment: C.I. I. Pigment Yellow 150 8 parts by weight Acrylic varnish: (solid content 20%) 102 parts by weight Diethylene glycol monomethyl ether 50 parts by weight Tetraethylene glycol dimethyl ether 30 parts by weight Blue colored material Same as the red colored material so that each of the compositions shown below is used. It was produced by the method.

Blue pigment: C.I. I. Pigment Blue 15 50 parts by weight Purple pigment: C.I. I. Pigment Violet 23 2 parts by weight Dispersant: “Sols Birds 20000” manufactured by Zeneca Co., Ltd. 6 parts by weight Acrylic varnish (solid content 20%) 200 parts by weight Diethylene glycol monomethyl ether 100 parts by weight Tetraethylene glycol dimethyl ether 60 parts by weight <Preparation of color filter substrate>
A red (R) ink is applied to the opening of the black matrix 2 on the glass substrate 1 by using an ink jet printing apparatus equipped with a 108 pl, 150 dpi head (manufactured by Seiko Instruments Inc.) using the color inks of the R, G, B colors. , Green (G), and blue (B) were filled in the region surrounded by the partition walls. Thereafter, heating is carried out at 200 ° C. for 30 minutes on a hot plate to form colored pixel patterns 3 (R), 3 (G), 3 (B) as shown in FIG. It was.

  When the retardation in the thickness direction of these colored pixel patterns 3 (R), 3 (G), and 3 (B) was measured, they were 20 nm, −45 nm, and 4 nm, respectively.

<Production of phase-controlled color filter>
A polyimide film is formed on the colored pixel patterns 3 (R), 3 (G), and 3 (B) of the color filter substrate prepared above by spin coating, and baked at 230 ° C. for 1 hour, and then rubbed. A rubbing process was performed in a certain direction with a cloth, and an alignment film 4 was formed on the colored pixel pattern as shown in FIG.

  After the alignment treatment, the liquid crystal composition (B) layer was formed by spin coating. The film thickness of the liquid crystal layer after heating at 60 ° C. for 1 minute was 0.7 μm.

Next, the applied liquid crystal layer was exposed with an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. At this time, proximity exposure using a mask was performed so that only the colored pixel pattern 3 (G) could be exposed.

  Next, the substrate was immersed in acetone to remove the unexposed portion, and the liquid crystal retardation region 5 (G) was formed only on the colored pixel pattern 3 (G). In addition, a heating process at 150 ° C. for 30 minutes was performed to stabilize the liquid crystal layer.

  Thereafter, the polyimide was changed to the one for vertical alignment, and a film was formed by spin coating, followed by a baking process at 230 ° C. for 1 hour to form a vertical alignment film.

  Next, the layer of the liquid crystal composition (A) was formed by spin coating. The film thickness of the liquid crystal layer after heating at 60 ° C. for 1 minute was 0.7 μm.

Next, the applied liquid crystal layer was exposed with an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. At this time, proximity exposure using a mask was performed so that only the colored pixel pattern 3 (B) could be exposed.

  Further, the substrate was immersed in acetone to remove the unexposed portion, and the liquid crystal retardation region 5 (B) was formed only on the colored pixel pattern 3 (B). In addition, a heating process at 150 ° C. for 30 minutes was performed to stabilize the liquid crystal layer.

  Similarly, after the polyimide was formed on the colored pixel pattern, the layer of the liquid crystal composition (C) was formed by spin coating. The film thickness of the liquid crystal layer after heating at 60 ° C. for 1 minute was 0.7 μm.

Next, the applied liquid crystal layer was exposed with an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. At this time, proximity exposure using a mask was performed so that only the colored pixel pattern 3 (R) could be exposed.

  Next, the substrate was immersed in acetone to remove the unexposed portion, and the liquid crystal retardation region 5 (R) was formed only on the colored pixel pattern 3 (R). In addition, a heating process at 150 ° C. for 30 minutes was performed to stabilize the liquid crystal layer.

  The retardation in each pixel of the color filter obtained through the above steps is the sum of the retardation of the colored pixel pattern and the liquid crystal retardation layer, that is, 0 nm in the colored pixel (R) portion and − in the colored pixel (G) portion. It is estimated to be 5 nm and −1 nm in the colored pixel (B) portion.

Comparative Example 1
A color filter was produced in the same manner as in Example 1 except that the retardation layer and the liquid crystal retardation layer were not provided.

The color filters of the example and the comparative example obtained as described above are sandwiched by two deflecting films arranged so that their deflection axes are parallel and orthogonal, and a three-wavelength tube backlight (Tc = 6000K) is provided on the back surface. ) Was installed, and chromaticity measurement was performed from the front direction and an oblique 45 ° direction using a luminance meter (Part No. BM-5A: manufactured by Topcon Corporation). The results are shown in Tables 1 and 2 below. Table 1 shows the result of chromaticity measurement from the front direction, and Table 2 shows the result of chromaticity measurement from an oblique 45 ° direction. 4 and 5 are characteristic diagrams in which Tables 1 and 2 are plotted on the xy coordinates.

  As shown in the results of Tables 1 and 2 above, no significant change was observed in the appearance and chromaticity from the front direction, but in the oblique 45 ° direction, a reddish purple color was exhibited in the comparative example. In Example 1, it was confirmed that an achromatic gray was obtained by providing a retardation layer and performing retardation control.

Example 2
<Production of phase-controlled color filter>
(Adjustment of liquid crystal composition and calculation of relationship between film thickness and phase difference)
100 parts by weight of a nematic liquid crystal having a polymerizable group, 9 parts by weight of a chiral agent, and 5 parts by weight of a photoinitiator were dissolved in 420 parts of toluene to prepare a liquid crystal composition (A).

  A polyimide film was formed on the glass substrate 1 by spin coating, a baking process was performed at 230 ° C. for 1 hour, and then a rubbing treatment was performed in a certain direction with a rubbing cloth to form an alignment film.

Next, the liquid crystal composition (A) is applied onto the substrate subjected to the alignment treatment by a spin coating method, heated at 60 ° C. for 1 minute, and then, with an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source, Exposure was performed at an irradiation dose of 1000 mJ / cm ² . In addition, in the exposure process, it implemented in nitrogen atmosphere so that superposition | polymerization inhibition by the oxygen in air | atmosphere might not arise. Furthermore, in order to stabilize the liquid crystal layer, a liquid crystal retardation layer was formed through a heating process at 150 ° C. for 30 minutes. The film thickness of the formed liquid crystal retardation layer was 0.7 μm.

  It was 35 nm when the retardation of the thickness direction of the said liquid crystal phase difference layer was measured. Therefore, it was found that the retardation per 1 μm of the liquid crystal retardation layer was 50 nm.

<Formation of liquid crystal layer>
A polyimide film is formed on a color filter substrate manufactured in the same manner as in Example 1 by spin coating, and a baking process is performed at 230 ° C. for 1 hour, and then a rubbing process is performed in a certain direction with a rubbing cloth. As shown in FIG. 3, an alignment film 4 was formed on each colored pixel pattern 3 (R), 3 (G), 3 (B).

  After the alignment treatment, the liquid crystal composition (A) was applied by spin coating in the same manner as in Example 1.

Next, exposure was performed at an irradiation amount of 1000 mJ / cm ² by an ultraviolet irradiation device using an ultrahigh pressure mercury lamp as a light source. Further, a heating process was performed at 150 ° C. for 30 minutes for stabilization, and a liquid crystal retardation region 15 (R) was formed as shown in FIG. In this case, the application conditions of the liquid crystal composition (A) were controlled so that the film thickness of the liquid crystal retardation region 15 (R) was 0.2 μm.

  Next, in the same manner, application, exposure, and development are repeated, and the liquid crystal retardation region 15 (in the region surrounded by the partition on the alignment film on the colored pixel patterns 3 (G) and 3 (R) is also obtained. G) and 15 (R) were formed. In this case, the liquid crystal composition (A) is appropriately applied so that the thickness of the liquid crystal retardation region 15 (G) is 1.5 μm and the thickness of the liquid crystal retardation region 15 (B) is 0.5 μm. The conditions were adjusted.

  The retardation of the liquid crystal retardation layer by the liquid crystal composition (A) is 10 nm for the liquid crystal retardation region 15 (R), 75 nm for the liquid crystal retardation region 15 (G), and 25 nm for the liquid crystal retardation region 15 (B). In each pixel, the sum of the phase differences from the respective colored pixel patterns is 30 nm in the colored pixel (R) portion, 30 nm in the colored pixel (G) portion, and 29 nm in the colored pixel (B) portion, which are substantially the same.

The color filter of Example 2 obtained as described above is sandwiched between two deflection films arranged so that the deflection axes are parallel and orthogonal, and a three-wavelength tube backlight (Tc = 6000K) is provided on the back surface. It installed, and the chromaticity measurement was performed from the front direction and 45 degrees diagonal direction using the luminance meter (product number BM-5A: Topcon Co., Ltd. product). The results are shown in Table 3 and Table 4 below together with the results of the comparative example described above. Table 3 shows the result of the chromaticity measurement from the front direction, and Table 4 shows the result of the chromaticity measurement from the oblique 45 ° direction. 7 and 8 are characteristic diagrams in which Tables 4 and 52 are plotted on the xy coordinates.

  As shown in the results of Tables 3 and 4 above, no major changes were observed in the appearance and chromaticity from the front direction, but in the oblique 45 ° direction, a reddish purple color was exhibited in the comparative example. However, it was confirmed that an achromatic gray was obtained by providing a retardation layer in Example 2 and performing phase difference control.

1 is a schematic cross-sectional view showing a color filter including a phase difference control layer according to a first embodiment of the present invention. The figure which shows the retardation of the coloring fine pattern of a color filter Sectional drawing for demonstrating the manufacturing process of the color filter provided with the phase difference control layer shown in FIG. 1 is a schematic cross-sectional view showing a color filter including a phase difference control layer according to a first embodiment of the present invention. The characteristic view which shows the result of having performed chromaticity measurement from the front direction of the color filter which concerns on Example 1 and a comparative example. The characteristic view which shows the result of having performed chromaticity measurement from the diagonal 45 degree direction of the color filter which concerns on Example 1 and a comparative example. The characteristic view which shows the result of having performed chromaticity measurement from the front direction of the color filter which concerns on Example 2 and a comparative example. The characteristic view which shows the result of having performed chromaticity measurement from the diagonal 45 degree direction of the color filter which concerns on Example 2 and a comparative example.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Partition black matrix, 3 (R) ... Red pixel pattern, 3 (G) ... Green pixel pattern, 3 (B) ... Blue pixel pattern, 4 ... Orientation film, 5 (R), 5 ( G), 5 (B), 15 (R), 15 (G), 15 (B)... Phase difference control region.

Claims (10)

Forming a partition on the substrate;
Forming a plurality of colored pixel patterns having a predetermined retardation between the partition walls by an inkjet method;
A step of forming an alignment film subjected to alignment treatment on the colored pixel pattern, and a liquid crystal retardation layer is formed on the alignment film by a photolithography method corresponding to the retardation of each of the plurality of colored pixel patterns. Comprising the steps of :
The liquid crystal phase difference layer includes a plurality of liquid crystal phase difference regions corresponding to a plurality of coloring patterns, and the plurality of liquid crystal phase difference regions have retardations that correct retardation of the plurality of colored pixel patterns, and A method for producing a color filter, wherein the total of the retardation of the colored pixel pattern and the corresponding retardation of the plurality of liquid crystal retardation regions is substantially the same for each pixel .   The plurality of colored pixel patterns include a red pixel pattern, a blue pixel pattern, and a green pixel pattern, wherein the red pixel pattern and the blue pixel pattern have a positive retardation, and the green pixel pattern has a negative retardation. The method for producing a color filter according to claim 1, wherein   The liquid crystal retardation layer is made of a liquid crystal selected from the group consisting of a polymerizable nematic liquid crystal, a polymerizable cholesteric liquid crystal, and a homeotropically aligned polymerizable liquid crystal. Manufacturing method of color filter. The method for producing a color filter according to claim 1, wherein the plurality of liquid crystal retardation regions have different retardations for each of the plurality of colored pixel patterns.   The method for producing a color filter according to claim 4, wherein the retardation of the plurality of liquid crystal retardation regions has retardation corresponding to a wavelength region of light passing therethrough. 6. The color filter manufacturing method according to claim 1 , wherein the retardation of the plurality of liquid crystal retardation regions is opposite in sign to the retardation of the colored pixel pattern and has substantially the same absolute value. Method. The method for producing a color filter according to any one of claims 1 to 6 , wherein the plurality of liquid crystal retardation regions are made of a crosslinked cured product of a polymerizable liquid crystal composition that differs for each of the plurality of colored pixel patterns. . The method for producing a color filter according to claim 1 , wherein the plurality of liquid crystal retardation regions are made of a crosslinked cured product of the same polymerizable liquid crystal composition and have different film thicknesses. A color filter manufactured by the method according to claim 1 . A liquid crystal display comprising the color filter according to claim 9 .

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