JP2007183602A - Color filter, its production method and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a color filter having an excellent characteristic in the expansion of a viewing field angle from an oblique direction by the optimum phase difference compensation in each picture element at high productivity. <P>SOLUTION: The method for producing a color filter comprises: a stage where black matrixes are formed on a transparent substrate; a stage where a plurality of colored picture element layers having prescribed retardation are formed between the black matrixes by a photolithography process; and a stage where each phase difference control layer is formed on the plurality of colored picture element layers corresponding to the respective retardation by a printing process. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 a transparent substrate and having negative birefringence anisotropy, and an optical axis being transparent There is an example in which a retardation film (positive A plate) that is horizontal on a substrate and has positive birefringence anisotropy is used in combination (for example, see Patent Document 1).

  For the retardation control in these, a retardation film obtained by stretching a polycarbonate film or the like or a retardation 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 (birefringence retardation) is uniform in the plane, and is not set to the optimum retardation for each actually displayed pixel, and is not necessarily the optimum level. There is no phase difference compensation.

  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.

The known literature is described below.
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 accurately manufacturing 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 do. 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 each colored pixel layer of red, green and blue is different, and in red and blue, the optical axis is perpendicular to the transparent substrate, Since it has negative birefringence anisotropy, it shows positive retardation with respect to the vertical direction of the transparent substrate. Conversely, in green, the optical axis is perpendicular to the transparent substrate and has positive birefringence anisotropy. The present inventors have found that this is to show negative retardation with respect to the vertical direction of the transparent substrate. Normally, optical design is performed centering on green. Therefore, if the retardation of the red and blue colored pixel layers and the green colored pixel layer are significantly different from each other in positive and negative, red and blue leakage light is generated as described above. End up. The present invention has been made based on such findings.

  The first aspect of the present invention includes a step of forming a black matrix on a transparent substrate, a step of forming a plurality of colored pixel layers having a predetermined retardation between the black matrices by a photolithography method, and the plurality of colorings. Provided is a method for producing a color filter, comprising a step of forming a phase difference control layer by a printing method corresponding to each retardation on a pixel layer.

  In such a color filter manufacturing method, the plurality of colored pixel layers include a red pixel layer, a blue pixel layer, and a green pixel layer, and the red pixel layer and the blue pixel layer are positive with respect to the vertical direction of the transparent substrate. It has retardation, and a green pixel layer shall have negative retardation.

  The retardation control 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.

  Furthermore, the phase difference control layer includes a plurality of phase difference control regions corresponding to the plurality of colored pixel layers, and each phase difference control region may have a different retardation for each of the plurality of colored pixel layers. .

  In this case, it is desirable that the retardations of the plurality of phase difference control regions have retardations according to the wavelength range of light passing therethrough. Moreover, it is desirable that the plurality of phase difference control regions have a retardation that corrects the retardation of the plurality of colored pixel layers.

  In the above-described color filter manufacturing method, the retardation of the plurality of phase difference control regions has the opposite sign to the retardation of the colored pixel layer and can have substantially the same absolute value. In this case, the plurality of retardation control 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 layers.

  Moreover, the sum total of the retardation of a some colored pixel layer and the retardation of the some phase difference control area | region corresponding to it can be made substantially the same for every pixel. In this case, a plurality of retardation control regions can be formed by the crosslinked cured product 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 the retardation control layer is formed by the printing method, it is possible to reduce the environmental burden and significantly reduce the cost. In addition, by adjusting the retardation of the retardation control layer corresponding to the retardation of each colored pixel layer, 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. In particular, the retardation of the retardation control layer can be controlled without forming an alignment film for orienting the retardation control layer, and a color filter with a simple configuration can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 is a sectional view showing a color filter according to the first embodiment of the present invention. In FIG. 1, a black matrix 4 made of a light shielding material is provided at a position corresponding to a non-pixel portion on a transparent substrate 5 such as a glass substrate or a quartz substrate. Each color of the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B), each of which is light transmissive, corresponds to each pixel portion and corresponds to a pixel portion. Colored pixel layers 3 arranged in an array are stacked.

  Further, on the colored pixel layer 3 in the opening, for each pixel, a phase difference control composed of a phase difference control region 1 (R), 1 (G), 1 (B) made of a cured product of polymerizable liquid crystal. Layer 1 is laminated to form a color filter.

  In the present invention, the polymerizable liquid crystal composition refers to those in which the liquid crystal state 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 difference before cross-linking. Hardened while maintaining its isotropic property or has a glass transition temperature. When heated above the glass transition temperature, it exhibits a liquid crystal phase, and then cooled to below the glass transition temperature, thereby freezing the liquid crystal structure. It refers to a polymer liquid crystal that can be produced. In addition, each character of R, G, and B shall represent red, green, and blue in order.

  As shown in FIG. 2, each of the colored pixel layers 3 (R), 3 (G), and 3 (B) has different retardations (compounds of display light) for each color of red, green, and blue that pass through each pattern. (Refractive phase difference). The retardation in the present invention indicates a characteristic value of a retardation with respect to the thickness direction of the colored pixel layer 3 or the retardation control layer 1, that is, the vertical direction of the transparent substrate 5 unless otherwise specified. 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 layer 3 (R) and the blue pixel layer 3 (B) have positive retardation. The green pixel layer 3 (G) was found to have negative retardation.

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

In order to compensate for the retardation of these colored pixel layers 3 (R), 3 (G), and 3 (B), the retardation of each retardation control layer 1 is opposite in sign to the retardation of the colored pixel layer 3. Since the absolute values are preferably substantially the same, the retardation of the phase difference control region 1 (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. In addition, the retardation of the phase difference control region 1 (R) is preferably −100 nm to −0.1 nm.

  The polymerizable liquid crystal materials constituting the phase difference control regions 1 (R), 1 (G), and 1 (B) have nematic liquid crystal materials and cholesteric liquid crystal materials so as to have a retardation corresponding to the wavelength range of light passing through each layer. Alternatively, it is preferable to appropriately select a homeotropically aligned polymerizable liquid crystal material.

  That is, the polymerizable liquid crystal material constituting the phase difference control regions 1 (R), 1 (G), and 1 (B) has a function of giving a phase difference to light incident at a certain incident angle. In addition, any polymerizable liquid crystal material such as a chiral nematic liquid crystal (a liquid obtained by adding a chiral agent to a nematic liquid crystal) can be used without being limited to the nematic liquid crystal described above.

  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.

(Production method)
Next, with reference to FIG. 3, the manufacturing method of the color filter with the phase difference control layer 1 shown in FIG. 1 is demonstrated.
(Formation of black matrix)
First, as shown in FIG. 3A, a black matrix 4 for improving contrast is provided on a transparent substrate 5. As the transparent substrate 5, 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 4 can be formed using a known method. For example, a method of forming a thin film of metal or metal oxide on the transparent substrate 5 by a method such as sputtering and patterning it by a technique such as etching; a method such as pigment or dye in the photosensitive resin composition A method in which a colorant is mixed and formed as a photosensitive resin composition layer on the transparent substrate 5 and formed by a photolithography method; a method in which a black pigment or a thermosetting resin is dissolved in a solvent and formed by a printing method, or the like Is mentioned. The black matrix 4 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. In addition, the ink repellent agent bleeds out during the heating process, and the ink repellent agent adheres to the transparent substrate 5 and color loss may occur when the color ink is filled. To prevent this, As the ink agent, it is preferable to use a fluorine-containing compound. 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 layers 3 (R), 3 (G), 3 ( B) is formed. In the case of a liquid crystal display, a transparent conductive layer is further laminated, for example, opposed to a counter substrate on which an electrode such as a thin film transistor is formed, and an LCD is configured through the liquid crystal layer. In the following, the transparent substrate 5, the black matrix 4, and the red, green, and blue colored pixel layers 3 (R), 3 (G), 3
Together with (B), a color filter substrate 5a is obtained.

  Usually, the colored pixel layer 3 composed of the three primary colors of the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B) is arranged in a desired shape in the opening of the black matrix 4. The In this embodiment, a pixel pattern is formed by photolithography. The process consists of a process for forming a colored resin composition layer on a substrate, an exposure process, and a development process for removing unexposed parts that become unnecessary parts.

  Examples of the method for providing the colored resin 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 part is formed by ultraviolet light using an ultrahigh pressure mercury lamp or a semiconductor laser as a light source, or mirror projection using an optical system using convex and concave mirrors. And a divided exposure method in which a projection lens is provided and the irradiation surface is divided. 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.

  As the colorant of the colored resin composition, 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 colorant 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 colored resin composition is appropriately selected from materials used for manufacturing the known color filter substrate 5a 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.

  Specifically, the solvent used in the colored resin composition is diethylene glycol-n-butyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, tripropylene glycol methyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol- Examples thereof include n-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 dispersant for the colored resin composition 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 color with the phase difference control layer 1 is formed by laminating the phase difference control layer 1 on the colored pixel layers 3 (R), 3 (G), and 3 (B) by a method described later. In the present invention, the colored pixel layers 3 (R), 3 (G), and 3 (B) are used for the purpose of imparting the alignment regulating force of the polymerizable liquid crystal composition. In addition, after forming the alignment film 2, the phase difference control layer 1 may be formed to provide a color filter with the phase difference control layer 1.

  The retardation control layer 1 is formed by applying a different polymerizable liquid crystal composition for each pixel on the colored pixel layers 3 (R), 3 (G), and 3 (B) by a printing method. As the polymerizable liquid crystal composition, a nematic liquid crystal material, a cholesteric liquid crystal material, or a homeotropically aligned polymerizable liquid crystal material is appropriately selected so as to have retardation corresponding to the wavelength range of light passing through each phase difference control layer 1.

  Various methods such as a printing method using a relief plate or an intaglio plate can be selected as a method for applying a different polymerizable liquid crystal composition for each pixel by the printing method. In the present invention, however, JP-A-11-58921 It is preferable to use a publicly known method disclosed in Japanese Laid-Open Patent Publication No. 2000-289320.

  Specifically, a coating material containing a polymerizable liquid crystal composition is uniformly applied on a silicon blanket, and a non-image area is removed by pressing a relief plate or an intaglio, and then transferred onto a substrate to form a pattern. .

  The application | coating coating material containing a polymeric liquid crystal composition can form the coating film which is easy to form a pattern by containing a suitable solvent component. Furthermore, for the purpose of improving printability, for example, a filler component having a particle diameter of 10 to 100 nm may be contained in the coating material in an amount of 5 to 50% by weight.

  In the present invention, the solvent component in the coating material containing the polymerizable liquid crystal composition has the role of uniformly dissolving or dispersing the above-mentioned various components to maintain the coating material stably, and the viscosity of the coating material. By controlling the wettability and dryness, uniform coating properties are imparted to the silicon blanket. Also, the solvent component volatilizes on the silicon blanket and the solvent penetrates into the silicon blanket. It plays an important role in expressing and controlling transcription.

  Specific solvents satisfying these conditions include low-boiling ester solvents such as ethyl acetate, isopropyl acetate and butyl acetate, and ketones such as acetone, 2-butanone and cyclohexanone to improve solubility and volatility. In order to improve the dispersibility and coatability of solvents, high-boiling ester solvents such as ethyl lactate and propylene glycol acetate, and aromatic solvent systems such as toluene and xylene are used to improve leveling properties. Ether solvents such as propylene glycol monomethyl ether are preferably used. If necessary, a mixture prepared by mixing two or more solvents so as to meet the above conditions can be used. Moreover, it is preferable to adjust to 1-10 mPa * s as a viscosity of the coating material of this invention from uniform coating property and drying property.

  In the present invention, the coating material containing the polymerizable liquid crystal composition may contain additives such as a leveling agent, a dispersant, a viscosity modifier, an antifoaming agent, and an antioxidant as necessary within the scope of the present invention. In addition, it can be prepared.

Next, the retardation control layer 1 applied on the colored pixel layers 3 (R), 3 (G), and 3 (B) by a printing method is irradiated with ultraviolet rays having a predetermined irradiation amount to control the retardation. The polymerizable liquid crystal composition of layer 1 is three-dimensionally crosslinked and cured. In addition, when the ultraviolet rays irradiated to the phase difference control layer 1 cure the polymerizable liquid crystal, it is preferable to add a photopolymerization initiator to the polymerizable 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 polymerizable liquid crystal composition can be cured without being affected by oxygen, and the optical characteristics of the retardation control layer 1 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 polymerizable liquid crystal material at the time of ultraviolet irradiation can be promoted, and the optical characteristics of the phase difference control layer 1 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 polymerizable liquid crystal material of the retardation control layer 1 can be optically fixed, and a film-like film that is easy to handle as an optical film and stable at room temperature is obtained. be able to.

  Finally, the retardation control layer 1 is baked to a predetermined temperature and recured to stabilize the optical characteristics of the retardation control layer 1. At this time, the retardation control layer 1 can be heated and cured at a high temperature, but it is preferably 100 to 150 ° C. In this case, the optical characteristics of the phase difference control layer 1 can be further stabilized.

  As a result, finally, as shown in FIG. 3D, the phase difference control regions 1 (R), 1 (G), and 1 (B) having retardation corresponding to the display regions of the respective colors of the pixels. The phase difference control layer 1 is formed, and the color filter with the phase difference control layer 1 is completed.

  As described above, as the polymerizable liquid crystal composition that is different for each pixel, the polymerizable liquid crystal composition having a retardation of −100 nm to −0.1 nm in the retardation control region 1 (R), A polymerizable liquid crystal composition having a retardation of 0.1 nm to 100 nm is used for the retardation control region 1 (G), and a retardation of -100 nm to -0.1 nm is used for the retardation control region 1 (B). A polymerizable liquid crystal composition is selected.

  As described above, according to the first embodiment, the phase difference control regions 1 (R), 1 (G), and 1 (B) are adjusted 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.

<Second Embodiment>
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 4 made of a light-shielding material is provided at a position corresponding to a non-pixel portion on a transparent substrate 5 such as a glass substrate or a plastic substrate, and each opening of the black matrix 4 corresponding to a pixel portion. A colored pixel layer 3 in which the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B), which are all light transmissive, are arranged in the unit is laminated. This is the same 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. 1, the colored pixel layers 3 (R), 3 (G), 3 (B) A different polymerizable liquid crystal composition is laminated on each pixel, and retardation control regions 1 (R), 1 (G), 1 () having retardation corresponding to the wavelength range of light passing through each layer. B) is formed, whereas in the color filter according to the present embodiment, the same polymerizable liquid crystal is used for any pixel on the colored pixel layers 3 (R), 3 (G), and 3 (B). The composition is laminated, and phase difference control regions 15 (R), 15 (G), and 15 (B) having different film thicknesses are formed so as to have retardation corresponding to the wavelength range of light passing through each layer. It is.

  In this case, the retardation in the thickness direction of the phase difference control regions 15 (R), 15 (G), and 15 (B) and the thickness direction of each colored pixel layer 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 depending on the retardation value in the thickness direction of each colored pixel layer 3 (R), 3 (G), 3 (B).

  For example, the retardation in the thickness direction of the blue pixel layer 3 (B) was 5 nm, the retardation in the thickness direction of the green pixel layer 3 (G) was −40 nm, and the retardation in the thickness direction of the red pixel layer 3 (R) was 10 nm. In this case, for example, if the retardation of the phase difference control region 15 (B) is 15 nm, the retardation of the phase difference control region 15 (G) is 60 nm, and the retardation of the phase difference control region 15 (R) is 10 nm, each colored pixel The sum of the retardation in the thickness direction of the layers 3 (R), 3 (G), and 3 (B) and the retardation in the thickness direction of each phase difference control region 15 (R), 15 (G), and 15 (B) is 20 nm. Become equal to each other.

  Retardation of each phase difference control region 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 phase difference control regions 15 (R), 15 (G), and 15 (B) can be controlled by the film thickness.

  The retardation in the thickness direction of the phase difference control regions 15 (R), 15 (G), and 15 (B) and the retardation in the thickness direction of each colored pixel layer 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 phase difference control region 15 (B) is 5 nm, the retardation of the phase difference control region 15 (G) is 50 nm, and the retardation of the phase difference control region 15 (R) is 0 nm. For example, the sum of the retardation in the thickness direction of each of the phase difference control regions 15 (R), 15 (G), and 15 (B) and the retardation in the thickness direction of each colored pixel layer 3 is equal to each other at 10 nm. preferable. At this time, since the retardation of the phase difference control region 15 (R) is 0 nm, the film thickness of the phase difference control region 15 (R) is 0, which means that the phase difference control region 15 (R) is not provided. It becomes.

  Thus, according to the value of retardation in the thickness direction of each colored pixel layer 3, the film thickness of each phase difference control region is such that the sum of the retardation in the thickness direction of each phase difference control region is equal to each other for each pixel. By controlling this, it becomes 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, the colored pixel layers 3 (R), 3 (G),
The coating film thickness by printing of the polymerizable liquid crystal composition on 3 (B) needs to be appropriately controlled for each pixel so that the retardation control layer 1 having a film thickness corresponding to the required retardation is formed. There is. Naturally, the film formation of the polymerizable liquid crystal composition is not performed on the pixel portion that does not require the phase difference control region.

<Third Embodiment>
FIG. 9 is a cross-sectional view showing a color filter according to the third embodiment of the present invention.
As shown in FIG. 9, in the color filter having the phase difference control layer 1 of the present invention, the pixel portion is an aperture portion on the transparent substrate 5, and the position corresponding to the non-pixel portion is made of a light-shielding material. Further, a black matrix 4 (indicated by abbreviation “BM” in the figure) is laminated, and all of them are light transmissive on the transparent substrate 5 in the fine region 4a of each aperture of the black matrix 4. A colored pixel layer 3 formed by arranging each color pattern of the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B) is laminated, and further on the colored pixel layer 3. Has a structure in which an alignment film 2 and a retardation control layer 1 made of a polymerizable liquid crystal are laminated as retardation control regions 1 (R), 1 (G), and 1 (B) for each fine region 4a. Is.

  In the present invention, the polymerizable liquid crystal composition refers to those in which the liquid crystal state 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 difference before cross-linking. Cured while maintaining the isotropic property or has a glass transition temperature, and when heated above the glass transition temperature, exhibits a liquid crystal phase, and then cools below the glass transition temperature to freeze the liquid crystal structure. A high-molecular liquid crystal that can be used. Hereinafter, the description of “light-transmitting” may be omitted for each color pattern constituting the colored pixel layer 3. In addition, the letters R, G, and B represent red, green, and blue in this order, and so on.

  The red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B) in the fine area 4a are respectively red, which passes through the fine areas 4a, as shown in FIG. It has different retardation amount for each light of green and blue. This retardation amount has various values depending on the material constituting it, the thickness, the processing method, and the like, but the inventors have found that R and B are positive retardation and G is negative retardation.

  Specifically, in the pixel in the fine region 4a of the blue pixel layer 3 (B), the retardation amount in the thickness direction of the pixel is 0.1 nm to 100 nm, so the phase difference control layer 1 in the fine region 4a. In the phase difference control region 1 (B), the phase difference value is preferably -100 nm to -0.1 nm.

  In the fine region 4a of the green pixel layer 3 (G), the retardation amount is −100 nm to −0.1 nm. Therefore, the phase difference value of the phase difference control region 1 (G) of the fine region 4a is 0. It is preferable to take 1 nm to 100 nm.

  In the fine region 4a of the red pixel layer 3 (R), the retardation amount is 0.1 nm to 100 nm. Therefore, the phase difference value of the phase difference control region 1 (R) of the fine region 4a is −100 nm to − It is preferable to take 0.1 nm.

  The phase difference control regions 1 (R), 1 (G), and 1 (B) of the phase difference control layer 1 in each fine region 4a have a retardation amount corresponding to the wavelength range of light passing through each fine region 4a. As described above, at least different polymerizable liquid crystal materials such as nematic liquid crystal material, cholesteric liquid crystal material, or homeotropically aligned polymerizable liquid crystal, or a mixture of two or more kinds may be appropriately selected, or the same polymerizable property may be selected. It is preferable that the phase difference control layer 1 having a different thickness is formed using a liquid crystal material and has a phase difference value corresponding to each fine pixel.

  The polymerizable liquid crystal material constituting the phase difference control layer 1 is not limited to the nematic liquid crystal described above, and may be a chiral nematic liquid crystal as long as it has a function of giving a phase difference to light incident at a certain incident angle. Any polymerizable liquid crystal material such as (nematic liquid crystal added with a chiral agent) 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, a manufacturing method of the color filter with the retardation control layer 1 having such a configuration will be described with reference to FIG.
(Configuration of the color filter substrate 5a)
First, the color filter is provided with a black matrix 4 for improving contrast on the transparent substrate 5 (FIG. 10A), and then the red (R), green (G), and blue (B) colored pixel layers 3 ( R), 3 (G), 3 (B) (FIG. 10 (b)), and when this is used for a liquid crystal display (LCD), the alignment film 2 (FIG. 10 (c)) And a transparent conductive layer are sequentially laminated. For example, an LCD is formed through a liquid crystal layer so as to face a counter substrate on which an electrode such as a thin film transistor is formed. Hereinafter, the transparent substrate 5, the black matrix 4, and the red, green, and blue colored pixel layers 3 are combined to form a color filter substrate 5 a.

  The colored pixel layer 3 is provided at the opening of the black matrix 4, and a pixel pattern composed of the three primary colors of the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B) is usually desired. It is arranged in the shape of. Examples of the general formation method include a pigment dispersion method, a dye method, an electrodeposition method, a printing method, a transfer method, and an ink jet method. In the present invention, the colored resin composition is patterned by any of these methods. May be. Thereafter, the colored pixel layer 3 is formed through a heating process described later.

(Material for colored pixel layer 3)
A pigment, dye, etc. can be used for the coloring agent of the said colored resin composition. 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, etc. can be used. Furthermore, in order to obtain a desired hue, two or more kinds of materials can be mixed and used.

  The thermosetting resin of the colored resin composition is appropriately selected from known color filter substrate materials 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, an acrylic resin is preferably used when manufacturing a color filter that requires heat resistance and light resistance.

  Specific examples of the solvent for the colored resin composition include diethylene glycol-n-butyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, tripropylene glycol methyl ether, dipropylene glycol-n-propyl ether, and dipropylene glycol-n. -Butyl ether, tripropylene glycol-n-butyl ether, propylene glycol phenyl ether and the like can be mentioned. 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 mixed and adjusted so that two or more types of solvent may meet the said conditions as needed can be used.

  The dispersant for the colored resin composition is used for improving the dispersion of the pigment in the resin. As the dispersant, an ionic or nonionic surfactant 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.

(Material of transparent substrate 5)
As the transparent substrate 5, 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.
(Material of black matrix 4)
The black matrix 4 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 technique such as etching, a coloring agent such as a pigment or a dye in the photosensitive resin composition Examples thereof include a method of forming a photosensitive resin composition layer on a substrate and forming it by a photolithography method, a method of forming a black pigment and a thermosetting resin in a solvent, and forming them by a printing method.

(Material of alignment film 2)
In addition, as a material for forming the alignment film 2 for aligning the polymerizable liquid crystal composition as the retardation control layer 1, polyimide, polyamide, polyvinyl alcohol, or the like is usually used. In the present invention, it is applied by spin coating, It is formed by drying and firing. By subjecting such an alignment film 2 to a rubbing treatment, alignment ability 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 rotated while being in contact with the alignment film 2 formed on the color filter substrate 5a. A method of rubbing the alignment film 2 with a rubbing cloth is usually employed by transporting the color filter substrate 5a with the alignment film 2 while fixing the film.

(Formation of retardation control layer 1)
Next, after forming the retardation control layer 1 made of polymerizable liquid crystal on the alignment film 2 formed on the color filter substrate 5a, the retardation control layer 1 (R) is irradiated by irradiating with a predetermined amount of ultraviolet rays. 1 (G) and 1 (B) are three-dimensionally crosslinked and cured (FIG. 10 (d)). At this time, it is preferable to add a photopolymerization initiator to the polymerizable liquid crystal material in order to cure the polymerizable liquid crystal of the phase difference control layer 1 with the ultraviolet rays irradiated to the phase difference control layer 1. . The irradiation amount of ultraviolet rays is 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 irradiated with ultraviolet rays is an inert gas atmosphere such as a nitrogen atmosphere. Thereby, it can harden | cure without being influenced by oxygen and the optical characteristic of the phase difference control layer 1 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 polymerizable liquid crystal material at the time of ultraviolet irradiation can be promoted, and the optical characteristics of the retardation control layer 1 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 polymerizable liquid crystal material of the retardation control layer 1 can be optically fixed, and a film-like film that is easy to handle as an optical film and stable at room temperature is obtained. be able to.

  Finally, the retardation control layer 1 is baked to a predetermined temperature and recured to stabilize the optical characteristics of the retardation control layer 1. At this time, the retardation control layer 1 can be heated and cured at a high temperature, but it is preferably 100 ° C. to 150 ° C. In this case, the optical characteristics of the phase difference control layer 1 can be further stabilized.

  Thereby, finally, a color filter in which the phase difference control layer 1 having the fine regions 1 (R), 1 (G), and 1 (B) corresponding to the display regions of the respective colors of the pixels is formed is manufactured ( FIG. 10 (d)).

  As described above, according to the present embodiment, the phase difference control layer 1 for controlling the phase difference is patterned in accordance with the display areas of the respective colors of the pixels, the fine areas 1 (R), 1 (G), 1 ( B), and these fine regions are adjusted so as to have a retardation amount corresponding to the wavelength region of the light passing through each fine pixel, so that the polarization of light passing through the display region of each color of the pixel There is no variation in state. 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 neutral black can be reproduced, exhibiting excellent display characteristics. Can do.

  Hereinafter, although the more concrete Example about embodiment described above is shown, this invention is not limited to these Examples at all. 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>
(Production of polymerizable liquid crystal composition for phase difference control)
A polymerizable 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 320 parts by weight of toluene and 100 parts by weight of cyclohexanone. The polymerizable liquid crystal composition (A) was mixed with 9 parts by weight of a chiral agent to obtain a polymerizable liquid crystal composition (B). A nematic liquid crystal in the polymerizable liquid crystal composition (A) was replaced with a nematic liquid crystal having a higher birefringence, and a polymerizable liquid crystal composition (C) was prepared at the same mixing ratio.

Next, the polymerizable liquid crystal composition (B), the polymerizable liquid crystal composition (A), and the polymerizable liquid crystal composition (C) were respectively applied to the three glass transparent substrates 5 by a printing method. A control layer 1 was formed. That is, the coating material was applied to a blanket cylinder around which a silicon blanket was wound using a slit die to form a uniform film on the silicon blanket. Thereafter, the phase difference control layer 1 was formed by transferring the film formed on the silicon blanket as it was onto the alignment film. Next, the thickness of the retardation control layer 1 after heating at 60 ° C. for 1 minute was 0.7 μm. Next, the phase difference control layer 1 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, 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 retardation control layer 1, the retardation control layer 1 was formed by a heating process at 150 ° C. for 30 minutes.

When the retardation in the thickness direction of the retardation control layer 1 was measured, the thickness of the transparent substrate 5 on which the retardation control layer 1 was formed with the polymerizable liquid crystal composition (B) was 40 nm, and the retardation was measured with the polymerizable liquid crystal composition (A). The thickness was -5 nm in the transparent substrate 5 on which the phase difference control layer 1 was formed, and -20 nm in the transparent substrate 5 on which the phase difference control layer 1 was formed with the polymerizable liquid crystal composition (C).

Below, the manufacturing method of the color filter by this embodiment is demonstrated.
(Process for producing black matrix 4)
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 a transparent substrate 5 of a non-alkali 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 the non-pixel region of the transparent substrate 1 is formed as shown in FIG. A black matrix 4 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 resist)
[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”)
Using each of the above pigments, red, green and blue colored resin compositions were prepared.
(Color filter substrate manufacturing process)
A colored resin composition using the coating materials of the R, G, and B colors is used for the openings of the black matrix 4 on the transparent substrate 5, and red (R), green (G), The blue (B) colored pixel layer 3 was patterned. Thereafter, heating is performed at 200 ° C. for 30 minutes on a hot plate to form colored pixel layers 3 (R), 3 (G), and 3 (B) as shown in FIG. Obtained.

When the retardation in the thickness direction of these colored pixel layers 3 (R), 3 (G), and 3 (B) was measured, they were 20 nm, −45 nm, and 4 nm, respectively.
(Formation process of phase difference control layer 1)
The polymerizable liquid crystal composition (B) is coated on the green colored pixel layer 3 (G) in the region surrounded by the black matrix 4 of the color filter substrate 5a produced as described above by a printing method, so that the phase difference is obtained. A control layer 1 was formed. That is, the coating material was applied to a blanket cylinder around which a silicon blanket was wound using a slit die to form a uniform film on the silicon blanket. Thereafter, the blanket cylinder is pressed onto the glass relief plate corresponding to the pixel portions of the colored pixel layers 3 (R) and 3 (B) to remove the non-pixel portion, and the pattern remaining on the silicon blanket is subsequently colored. The phase difference control layer 1 in the phase difference region 1 (G) was formed by transferring onto the pixel layer 3 (G). The film thickness of the retardation control layer 1 after heating at 60 ° C. for 1 minute was 0.7 μm.

Next, the retardation control layer 1 applied in the previous step 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. Furthermore, in order to stabilize the phase difference control layer 1, a heating process was performed at 150 ° C. for 30 minutes to form the phase difference control region 1 (G).

  Next, the polymerizable liquid crystal composition (A) is applied to the upper surface of the blue pixel layer 3 (B) by a printing method similar to that used to form the polymerizable liquid crystal composition (B), and the polymerizable liquid crystal composition (C) was applied to the upper surface of the red pixel layer 3 (R). The film thicknesses of the retardation control layer 1 of the polymerizable liquid crystal composition (A) and the polymerizable liquid crystal composition (C) after heating at 60 ° C. for 1 minute are the same as those of the polymerizable liquid crystal composition (B). It was 0.7 μm.

Next, the retardation control layer 1 filled in the previous step 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. Furthermore, in order to stabilize the phase difference control layer 1, a heating process was performed at 150 ° C. for 30 minutes to form the phase difference control regions 1 (B) and 1 (R).

  The retardation in each pixel of the color filter formed with the retardation control layer 1 obtained through the above steps is the sum of the retardations of the colored pixel layer 3 and the retardation control layer 1, that is, the red colored pixel layer (R ) Portion is estimated to be 0 nm, the green colored pixel layer (G) portion is estimated to be -5 nm, and the blue colored pixel layer (B) portion is estimated to be -1 nm.

<Comparative Example 1>
A color filter was produced in the same manner as in Example 1 except that the phase difference control layer 1 was not provided.

  The color filters of Examples 1 and 2 and Comparative Example obtained as described above are sandwiched between two deflection films arranged so that the deflection axes are parallel and orthogonal, and a three-wavelength tube backlight ( Tc = 6000K) 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. 5 and 6 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 by providing the phase difference control layer 1 and performing phase difference control, an achromatic gray color was obtained.

<Example 2>
(Production of phase-controlled color filter)
(Adjustment of polymerizable liquid crystal composition and calculation of relationship between film thickness and retardation)
100 parts by weight of nematic liquid crystal having a polymerizable group, 9 parts by weight of chiral agent, and photoinitiator 5
A part by weight was dissolved in 420 parts of toluene to prepare a polymerizable liquid crystal composition (D).
A polymerizable liquid crystal composition (D) was applied on a glass transparent substrate 5 by a printing method. That is, the coating material was applied to a blanket cylinder around which a silicon blanket was wound using a slit die to form a uniform film on the silicon blanket. Thereafter, the phase difference control layer 1 was formed by transferring the film formed on the silicon blanket as it was onto the alignment film. Next, it heated at 60 degreeC for 1 minute. Next, the phase difference control layer 1 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, 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 retardation control layer 1, the retardation control layer 1 was formed by a heating process at 150 ° C. for 30 minutes. The film thickness of this phase difference control layer 1 was 0.7 μm.

It was 35 nm when the retardation of the thickness direction of the said phase difference control layer 1 was measured. Therefore, it was found that the phase difference per 1 μm thickness of the phase difference control layer 1 was 50 nm.
(Formation of retardation control layer 15)
The polymerizable liquid crystal composition (D) was applied by a printing method onto the red pixel layer 3 (R) surrounded by the black matrix 4 of the color filter substrate 5a produced in the same manner as in Example 1. That is, the coating material was applied to a blanket cylinder around which a silicon blanket was wound using a slit die to form a uniform film on the silicon blanket. Thereafter, the blanket cylinder is pressed onto the glass relief plate corresponding to the pixel portions of the colored pixel layers 3 (G) and 3 (B) to remove the non-pixel portions, and subsequently the coating film remaining on the silicon blanket The pattern was transferred onto the colored pixel layer 3 (R). 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 at 150 ° C. for 30 minutes was performed for stabilization, and a phase difference control region 15 (R) was formed as shown in FIG.

  Subsequently, phase difference control regions 15 (G) and 15 (B) were formed on the green pixel layer 3 (G) and the blue pixel layer 3 (B) in the same manner by a printing method. In this case, the coating amount of the polymerizable liquid crystal composition (D) is 0.2 μm for the retardation control region 15 (R) and 1.5 μm for the retardation control region 15 (G). For the phase difference control region 15 (B), the printing conditions were adjusted as appropriate so that the film thickness was 0.5 μm.

  The retardation of the retardation control layer 15 by the polymerizable liquid crystal composition (D) is 10 nm in the retardation control region 15 (R), 75 nm in the retardation control region 15 (G), and the retardation control region 15 (B). The total phase difference with each colored pixel layer 3 in each pixel is 30 nm in the colored pixel layer (R) portion, 30 nm in the colored pixel layer (G) portion, and 29 nm in the colored pixel layer (B) portion, It becomes almost 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. 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 3 and 4 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 by providing the phase difference control layer 15 in Example 2 and performing phase difference control, an achromatic gray color was obtained.

<Example 3>
(Material of retardation control layer 1)
A polymerizable 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 and 42 parts of diethylene glycol diethyl ether. The polymerizable liquid crystal composition was mixed with 9 parts by weight of a chiral agent to obtain a polymerizable liquid crystal composition (B).

(Formation process of alignment film 2)
First, a polyimide film was formed on a transparent substrate 5 made of 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 2.

(Characteristic measurement of phase difference control layer 1)
Next, the retardation control layer 1 was formed by spin coating the polymerizable liquid crystal product (B) on the substrate subjected to the alignment treatment. The film thickness after heating at 60 ° C. for 1 minute was 0.7 μm. 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. 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, a stable retardation control layer 1 was formed through a heating process at 150 ° C. for 30 minutes. It was 40 nm when the retardation of the thickness direction of this phase difference control layer 1 was measured.

  Moreover, the polyimide used above was changed for vertical alignment, and the alignment film 2 was formed in the same manner. At this time, the rubbing process is not performed.

Next, the polymerizable liquid crystal product (A) was formed by spin coating on the substrate on which the alignment film 2 was formed. The film thickness after heating at 60 ° C. for 1 minute was 0.2 and 1.0 μm. Next, exposure was performed at an irradiation amount of 000 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, the stabilized retardation control layer 1 was formed through a heating process at 150 ° C. for 30 minutes. When the retardation in the thickness direction of the retardation control layer 1 was measured, it was −6 nm and −20 nm at the film thicknesses of 0.3 μm and 1.0 μm, respectively.

Below, the manufacturing process of the color filter by a present Example is demonstrated.
(Formation process of colored pixel layer 3)
A black matrix 4 made of a chromium thin film was formed on a transparent substrate 5 made of a glass substrate. Next, red, green and blue coloring compositions are formed in the gaps of the black matrix 4 by photolithography, and the red pixel layer 3 (R), the green pixel layer 3 (G) and the blue pixel layer 3 (B). Each of the colored pixel layers 3 was formed. The retardation in the thickness direction of these colored pixel layers 3 was measured and found to be 22 nm, −40 nm, and 3 nm in the red pixel layer 3 (R), the green pixel layer 3 (G), and the blue pixel layer 3 (B), respectively. It was.

(Formation process of alignment film 2)
On the color filter substrate 5a produced above, a thermosetting resin composition mainly composed of an epoxy compound is applied, and after drying, a flat film layer having a thickness of 1.2 μm is formed through a heat process at 230 ° C. for 1 hour. did. Next, a polyimide film was formed 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 2 on the flat film layer.

(Formation process of phase difference control layer 1)
After the alignment treatment, the polymerizable liquid crystal product (B) was formed by spin coating. The film thickness after heating at 60 ° C. for 1 minute was 0.7 μm. 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. At this time, pattern exposure using a mask was performed so that only the green pixel layer 3 (G) could be exposed.

  Next, the substrate was immersed in acetone to remove the unexposed portion, and the phase difference control layer 1 was formed only on the green pixel layer 3 (G). Furthermore, in order to stabilize the phase difference control layer 1, a heating process was performed at 150 ° C. for 30 minutes.

  Next, the polyimide was changed into one for vertical alignment and formed by spin coating, and a baking process was performed at 230 ° C. for 1 hour to form the alignment film 2 on the flat film layer.

Next, the polymerizable liquid crystal product (A) was formed by spin coating. The film thickness after heating at 60 ° C. for 1 minute was 0.3 μm. 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. At this time, pattern exposure using a mask was performed so that only the colored pixel layer 3 (B) could be exposed.

  Next, the substrate was immersed in acetone to remove the unexposed portion, and the phase difference control layer 1 was formed only on the colored pixel layer 3 (B). Furthermore, in order to stabilize the phase difference control layer 1, a heating process was performed at 150 ° C. for 30 minutes.

  Similarly, after forming the polyimide alignment film on the flat film, the polymerizable liquid crystal product (A) is formed to a thickness of 1.0 μm, and the retardation control layer 1 is formed only on the colored pixel layer 3 (R). Formed.

  When the color filter obtained by the above process is sandwiched by a deflecting film so that the deflection axes are parallel, and a backlight is installed on the back side, it is the same as when observed from the front even if the angle is increased. About black display was confirmed. In Example 3, an alignment film for orienting the retardation control layer was formed. However, as in Example 1 and Example 2, the retardation control effect by the retardation control layer was greatly different without forming the alignment film. There was no.

  The technique according to the present invention is not limited to a vertically aligned liquid crystal display, but can be applied to other liquid crystal display devices such as TN, OCB, and IPS.

It is a schematic sectional drawing which shows the color filter provided with the phase difference control layer which concerns on the 1st Embodiment of this invention. It is a figure which shows the retardation of the coloring pixel layer of each color of a color filter. It is sectional drawing for demonstrating the manufacturing process of the color filter provided with the phase difference control layer shown in FIG. It is a schematic sectional drawing which shows the color filter provided with the phase difference control layer which concerns on the 2nd Embodiment of this invention. It is a 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 Comparative Example 1. FIG. It is a 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 Comparative Example 1. FIG. It is a 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 Comparative Example 1. FIG. It is a 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 Comparative Example 1. FIG. It is a schematic sectional drawing which shows the color filter provided with the phase difference control layer which concerns on Example 3 of this invention. It is process drawing for demonstrating the manufacturing process of the color filter provided with the phase difference control layer shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 15 ... Phase difference control layer 1 (R), 1 (G), 1 (B), 15 (R), 15 (G), 15 (B) ... Phase difference control area 2 ... Alignment film 3 ... colored pixel layer 3 (R) ... red pixel layer 3 (G) ... green pixel layer 3 (B) ... blue pixel layer 4 ... black matrix 5 ... transparent Substrate 5a Color filter substrate

Claims (12)

  A step of forming a black matrix on a transparent substrate, a step of forming a plurality of colored pixel layers having a predetermined retardation between the black matrices by a photolithography method, and corresponding to each retardation on the plurality of colored pixel layers And the manufacturing method of the color filter characterized by including the process of forming a phase difference control layer with a printing method.   2. The color filter according to claim 1, wherein the retardation control layer comprises 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.   The phase difference control layer includes a plurality of phase difference control regions corresponding to the plurality of colored pixel layers, and each phase difference control region has a different retardation for each of the plurality of colored pixel layers. The manufacturing method of the color filter of Claim 1 or 2.   4. The retardation of each of the plurality of phase difference control regions related to the phase difference control layer has a retardation corresponding to a wavelength range of light corresponding to each of the colored pixel layers. 5. The manufacturing method of the color filter of description.   5. The color according to claim 1, wherein the retardation of the plurality of phase difference control regions related to the phase difference control layer has a retardation for correcting the retardation of the plurality of colored pixel layers. A method for manufacturing a filter.   6. The retardation of the plurality of phase difference control regions related to the phase difference control layer is opposite in sign to the retardation of the colored pixel layer and has substantially the same absolute value. A method for producing a color filter according to one item.   7. The retardation of the plurality of retardation control regions related to the retardation control layer is made of a crosslinked cured product of a polymerizable liquid crystal composition that differs for each of the plurality of colored pixel layers. A method for producing a color filter according to claim 1.   8. The color according to claim 1, wherein the total of the retardations of the plurality of colored pixel layers and the retardations of the plurality of phase difference control regions corresponding thereto are substantially the same for each pixel. A method for manufacturing a filter.   9. The color filter according to claim 1, wherein the plurality of retardation control regions are made of a crosslinked cured product of the same polymerizable liquid crystal composition and have different film thicknesses. 10. Production method.   The plurality of colored pixel layers include a red pixel layer, a blue pixel layer, and a green pixel layer, wherein the red pixel layer and the blue pixel layer have a positive retardation, and the green pixel layer has a negative retardation. The method for producing a color filter according to claim 1, wherein the color filter is a color filter.   A color filter manufactured by the method according to claim 1.   A liquid crystal display comprising the color filter according to claim 11.