JP2008287204A - Color filter for transflective liquid crystal display device and its manufacturing method, and transflective liquid crystal display device using the color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a color filter, which does not cause any display defects due to screen glare or disorder of liquid crystal alignment, by a simple processing in a liquid crystal display device using a semi-transmissive color filter having a light scattering layer in a reflection region. <P>SOLUTION: The color filter substrate for the transflective liquid crystal display device, which is used for the transflective liquid crystal display device capable of performing a display using reflected light and a display using transmitted light, and is composed of the reflection region used for the display using the reflected light and a transmission region used for the display using the transmitted light, and in which a plurality of pixels having coloring layers are arranged two-dimensionally on a transparent substrate, is characterized in that it has the light scattering layer on the coloring layer of the reflection region and a flattening layer is formed on the light scattering layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a color filter for a transflective liquid crystal display device having both a transmissive liquid crystal display and a reflective liquid crystal display, a manufacturing method thereof, and a transflective liquid crystal display device using the same.

  Currently, liquid crystal display devices are used in various applications such as notebook PCs, portable information terminals, desktop monitors, and digital cameras, taking advantage of characteristics such as light weight, thinness, and low power consumption. In a liquid crystal display device using a backlight, it is required to increase the utilization efficiency of backlight light in order to reduce power consumption, and a high transmittance of a color filter is required. On the other hand, the transmittance of the color filter has been improved year by year, but it has become impossible to expect a significant reduction in power consumption due to the improved transmittance. Recently, the development of a reflective liquid crystal display device that does not require a backlight light source, which consumes a large amount of power, has been promoted, and the power consumption can be significantly reduced by about 1/7 compared to a transmissive liquid crystal display device. Has been announced (for example, see Non-Patent Document 1). The reflective liquid crystal display device has lower power consumption than the transmissive liquid crystal display device and has the advantage of excellent visibility in the outdoors, but the display becomes dark in a place where sufficient ambient light intensity is not secured, There is a problem that visibility becomes extremely bad. In order to make the display visible even in a dark environment, (1) a backlight is provided, a part of the reflective layer is notched, and a part is a transmissive display system and a part is a reflective display system. Liquid crystal display device, transflective display system (so-called transflective liquid crystal display device, hereinafter simply referred to as transflective liquid crystal display device; see Non-Patent Document 2, for example), (2) front light is provided LCD devices have been devised.

  In a transflective liquid crystal display device in which a notch is formed in a part of a reflective layer and a backlight is provided, a transmissive display using backlight and a reflective display using ambient light coexist in one pixel. Regardless of the light intensity, display with good visibility can be performed (see, for example, Patent Document 1). However, since two types of display methods coexist in one display device, if a function necessary for reflective display is added to the display device, there may be a negative effect in transmissive display. One of the reasons is that, in the transmissive display, the backlight light incorporated in the device is the light source, whereas in the reflective display, there are various types of light sources such as sunlight and indoor fluorescent lamps depending on the environment used. There's a problem. A light source (such as sunlight or an indoor fluorescent lamp) used for reflection display is normally a non-scattered light because it is a point light source or a light source from a limited surface. Therefore, in reflection display, it is necessary to change non-scattered light to scattered light by some method. One of the currently used techniques is a so-called diffusion paste in which particles are dispersed in an adhesive layer between a front substrate and a polarizing film to give a scattering function. This diffusion paste is formed on the entire surface of the display device (transmission area and reflection area). In transmissive display, the polarization plane of the light incident on the diffusion paste is rotated, and the polarization is lost (depolarization), resulting in a problem of contrast reduction.

  Previously, a reflective film for reflecting incident ambient light was made of a mirror-like metal such as aluminum, but now it is on a resin film with an uneven surface. A reflective film in which a metal thin film is formed in a vacuum has been used. In such a concavo-convex reflective film, a rainbow is generated due to light interference, which causes a problem that the screen of the liquid crystal display device is glared.

In order to solve these problems, it has been considered to form a light scattering layer made of transparent particles and a transparent resin only in the reflective region (see, for example, Patent Document 4). This eliminates the light scattering layer in the transmissive region, thus eliminating the problem of reduced contrast in transmissive display. However, no detailed disclosure has been made regarding a method for eliminating the glare of the screen of the liquid crystal display device. Further, since the particles are dispersed in the light scattering layer, there is a problem that the film surface is uneven and the liquid crystal alignment is disturbed.
Japanese Patent Laid-Open No. 11-109417 (FIG. 1) JP 2005-255325 A JP 2002-341128 A JP 2005-99268 PR "Nikkei Microdevices separate volume flat panel display", 1998, p. 126. “Fine Process Technology Japan '99, Specialized Technology Seminar Text A5”, July 2, 1998, p. 6.

  The present invention was devised in view of the shortcomings of the prior art. In a liquid crystal display device using a transflective color filter having a light scattering layer only in the reflective region, the present invention is caused by screen glare or liquid crystal alignment disorder. An object of the present invention is to provide a color filter that does not cause display defects by a simple processing method.

  As a result of intensive studies to solve the problems of the prior art, the present inventors can obtain a liquid crystal display device free from display defects due to screen glare or liquid crystal alignment by the following color filters. I found something.

  The color filter of the present invention, the manufacturing method thereof, and the transflective liquid crystal display device using the same have the following configurations.

That is,
(1) Used in a transflective liquid crystal display device capable of displaying with reflected light and displaying with transmitted light, and is composed of a reflective area used for display with reflected light and a transmissive area used for display with transmitted light, and is colored In a color filter substrate for a transflective liquid crystal display device in which a plurality of pixels each having a layer are two-dimensionally arranged on a transparent substrate, the light scattering layer is provided on the colored layer in the reflective region, A color filter substrate for a transflective liquid crystal display device, wherein a planarizing layer is formed on the light scattering layer.
(2) The color filter substrate for a transflective liquid crystal display device according to (1), wherein the light scattering layer is formed by dispersing a matrix material and particles having different refractive indexes from the matrix material.
(3) The color filter substrate for a transflective liquid crystal display device according to (1) or (2), wherein the planarizing layer is formed only on the light scattering layer.
(4) The transflective liquid crystal according to any one of (2) to (3), wherein the average primary particle diameter of the particles dispersed in the light scattering layer is 1.5 μm or more and 3 μm or less. Color filter substrate for display devices.
(5) The color filter substrate for a transflective liquid crystal display device according to any one of (2) to (4), wherein a matrix material of the light scattering layer is non-photosensitive.
(6) The matrix material of the light scattering layer is formed of a thermosetting acrylic resin, and the planarizing layer is formed by photocuring a photosensitive resin (2) to (5) The color filter substrate for a transflective liquid crystal display device according to any one of 1).
(7) The matrix material of the light scattering layer is formed of a non-photosensitive polyimide resin, and the planarizing layer is formed by photocuring a photosensitive resin (2) to (5) The color filter substrate for a transflective liquid crystal display device according to any one of 1).
(8) The refractive index (n1) of the particles dispersed in the light scattering layer, the refractive index (n2) of the matrix material of the light scattering layer, and the refractive index (n3) of the planarizing layer have the following relationship (2) The color filter substrate for a transflective liquid crystal display device according to any one of (2) to (7).

(9) The transflective liquid crystal according to any one of (1) to (8), wherein the thickness of the laminated structure of the light scattering layer and the planarizing layer is 1.5 μm or more and 3.0 μm or less. Color filter substrate for display devices.
(10) The color filter substrate for a transflective liquid crystal display device according to any one of (1) to (9), wherein the thickness of the matrix material portion of the light scattering layer is 1.0 μm or less.
(11) The flattening layer is characterized in that a photosensitive acrylic resin and an inorganic powder having a refractive index higher than that of the photosensitive acrylic resin and an average primary particle diameter of 0.1 μm or less are dispersed (1 ) To (10) The color filter substrate for a transflective liquid crystal display device.
(12) Used in a transflective liquid crystal display device capable of displaying with reflected light and displaying with transmitted light, and is composed of a reflective region used for display with reflected light and a transmissive region used for display with transmitted light, and is colored A method of manufacturing a color filter substrate for a transflective liquid crystal display device, in which a plurality of pixels each having a layer are two-dimensionally arranged on a transparent substrate, and includes the following (A), (B), (C ) And (D) are sequentially performed. A method for producing a color filter for a transflective liquid crystal display device.
(A) forming a pixel composed of a colored layer on a transparent substrate;
(B) applying and drying a non-photosensitive light scattering layer forming composition,
(C) a step of applying a photosensitive planarizing layer-forming composition on the non-photosensitive light scattering layer and drying it;
(D) a step of exposing and developing the substrate on which the colored layer, the light scattering layer, and the planarizing layer are laminated, and forming the light scattering layer and the planarizing layer only on the pixels in the reflective region;
A process for producing a color filter substrate for a transflective liquid crystal display device, comprising:
(13) The color filter substrate for a transflective liquid crystal display device according to (1) to (11) or the color filter substrate for a transflective liquid crystal display device obtained by the production method according to claim 12 and a reflective region. A transflective liquid crystal display device in which liquid crystal is sandwiched between drive element side substrates having a reflective layer having a concavo-convex surface on the surface only.

  Since the present invention is configured as described above, it is possible to obtain a color filter for a transflective liquid crystal display device in which display defects do not occur due to screen glare or liquid crystal alignment disorder by simple processing.

  Embodiments of the present invention will be described below.

  The color filter of the present invention is a color filter for a transflective liquid crystal display device having a reflective region and a transmissive region in one pixel, and a light scattering layer is formed only in the reflective region, on the light scattering layer. It is important to have a structure in which planarization layers are stacked. Here, the transflective liquid crystal display device is characterized in that the reflective region of the counter substrate or the color filter is provided with a reflective film for reflecting external light, and the reflective region does not have such a reflective film. It is a liquid crystal display device. The formation of the color filter is not limited to the transparent substrate side such as glass or polymer film, but can also be performed on the driving element side substrate. The pattern shape of the color filter includes a stripe shape and an island shape, but is not particularly limited. A columnar fixed spacer may be disposed on the color filter as necessary.

  The position where the light scattering layer is formed is preferably on the colored layer. “On the colored layer” does not mean that the colored layer and the light scattering layer must be in contact with each other, and another layer may be formed between the colored layer and the light scattering layer. The colored layer here is a resin layer containing a colored component, and is composed of at least three color pixels of red, green, and blue. As the coloring component, any colorant can be used regardless of organic pigments, inorganic pigments, and dyes. As the resin component, materials such as a polyimide resin, an epoxy resin, an acrylic resin, a urethane resin, a polyester resin, and a polyolefin resin are preferably used. Both photosensitive and non-photosensitive materials can be used. As a method for forming the colored layer, a photolithography method, a transfer method, an ink jet method, or the like can be used.

In the light scattering layer, particles having a refractive index different from that of the matrix material are preferably dispersed in the matrix material. By including light diffusing particles in the matrix material, display glare due to specular reflection components can be suppressed and good display characteristics can be obtained, and there is no light scattering layer in the transmissive area, so there is no light scattering. The backlight can be used efficiently. As a matrix material, any material that can obtain a desired refractive index can be used, and only a transparent resin may be used. However, a nano-order inorganic powder is dispersed in the transparent resin to adjust the refractive index. Materials can also be used. Here, “transparent” specifically means that the average transmittance in the visible light region is 80% or more. As the transparent resin, both photosensitive and non-photosensitive can be used. As the photosensitive resin material, materials such as polyimide resin, epoxy resin, acrylic resin, urethane resin, polyester resin, polyolefin resin and the like can be used, and acrylic resin is preferably used. The photosensitive acrylic resin generally has at least an acrylic polymer, an acrylic polyfunctional monomer or oligomer, and a photopolymerization initiator in order to provide photosensitivity, but an epoxy monomer is added. Alternatively, a so-called acrylic epoxy resin may be used. As the non-photosensitive resin material, materials such as polyimide resin, epoxy resin, acrylic resin, urethane resin, polyester resin, and polyolefin resin can be used, and polyimide resin and acrylic resin are preferably used. When nano-order inorganic powder is dispersed in a transparent resin, Al ₂ O ₃ , ZnO, TiO ₂ , SiO ₂ or the like can be used as the inorganic powder. A preferable combination of a transparent resin and nano-order inorganic powder is a material in which titanium oxide is dispersed in an acrylic resin. The refractive index of the acrylic resin is about 1.5, but can be increased to nearly 1.8 by dispersing titanium oxide. Thereby, acrylic resin can be used as a high refractive index matrix material.

  As the particles for light scattering, materials such as inorganic oxide particles such as silica, alumina and titania, metal particles, resin particles such as acrylic, melamine, styrene, silicone and fluorine-containing polymer can be used. The average primary particle diameter of the light diffusing particles is preferably used in the range of 1.5 to 3 μm. When the average primary particle diameter is smaller than 1.5 μm, a rainbow is generated due to light interference, and the liquid crystal display screen is glared. When the average primary particle diameter is larger than 3 μm, the flattening layer is within the allowable film thickness range. Even if it is applied, it becomes difficult to obtain flatness. In particular, when the particle diameter of the light scattering particles is up to about 3.0 times the film thickness of the matrix material portion of the light scattering layer, it is more preferable because the flatness is particularly improved by the flattening layer. Here, the film thickness of the matrix material part of the light scattering layer refers to the film thickness of a part (part where particles are not present) formed only by the matrix material part constituting the light scattering layer. A schematic diagram is shown in FIG. The thickness of the laminated structure of the light scattering layer and the flattening layer is preferably smaller than the thickness of the liquid crystal layer, particularly in the range of 1/4 to 3/4 of the thickness of the liquid crystal layer.

  Conversely, when the film thickness is 3/4 or more of the thickness of the liquid crystal layer, the liquid crystal layer in the reflective region becomes thin, resulting in a display defect. In addition, in order to obtain a degree of flatness that does not cause alignment failure of liquid crystal when the film thickness of the laminated structure of the light scattering layer and the flattening layer is in the range of 1.5 μm to 3.0 μm, the film of the matrix material portion The thickness is particularly preferably 1.0 μm or less. When the film thickness of the matrix material portion exceeds 1.0 μm, it becomes difficult to flatten the surface because the laminated film thickness with the flattening layer is 1.5 μm. The flatness that does not cause display defects due to uneven alignment of liquid crystal when a display panel is used varies depending on the display mode, but the film thickness step in the flattened layer is preferably 0.5 μm or less. Here, “flat” in the present invention does not mean a film having no unevenness, but is flat if there is flatness that does not cause display defects due to uneven alignment of liquid crystal. . Therefore, if the film thickness step is 0.5 μm or less, it can be said that the present invention is flat.

For the planarization layer, any of an epoxy film, an acrylic epoxy film, an acrylic film, a siloxane polymer film, a polyimide film, a silicon-containing polyimide film, a polyimidesiloxane film, or a material in which inorganic powder is dispersed in a transparent resin is used. May be. Since it is necessary to make the refractive index different from that of the scattering particles in the light scattering layer, it is particularly preferable to use a polyimide film having a high refractive index and a material in which an inorganic powder is dispersed in a transparent resin. As the inorganic powder, Al ₂ O ₃ , ZnO, TiO ₂ , SiO ₂ or the like can be used. It is preferable to select an inorganic powder having a high refractive index, a light absorption edge of 400 nm (not more than a visible light region) or less, and high versatility. In particular, a material in which titanium oxide is dispersed in an acrylic resin has a high refractive index of titanium oxide of about 2.5. Therefore, the refractive index of the acrylic resin is changed to 1.5 to 1.8 by changing the amount of addition. It can be changed to near, and is particularly preferable. Titanium oxide can be preferably used because it has a light absorption edge of 360 nm and has high transparency in the visible light region and high versatility. Here, the refractive index can be measured using a prism coupling method or the like. Moreover, it is preferable that the average primary particle diameter of inorganic powder is 0.1 micrometer or less. When the average primary particle diameter of the inorganic powder is 0.1 μm or less, the flatness of the flattening layer is not impaired. If the thickness exceeds 0.1 μm, the flattening layer itself will be uneven, which is not preferable.

  When the refractive index of the particles dispersed in the light scattering layer is n1, the refractive index of the matrix material is n2, and the refractive index of the planarizing layer is n3, n1, n2, and n3 satisfy the following relational expression. preferable.

  If the absolute value of the difference in refractive index between the particles dispersed in the light-scattering layer and the matrix material is less than 0.05, sufficient light scattering will not occur at the interface between the matrix material and the particles, and the display by the specular reflection component will not occur. I can't hold the glare. Further, in order to reduce the thickness of the laminated structure of the light scattering layer and the flattening layer to 1.5 μm, it is necessary to set the thickness of the matrix material portion of the light scattering layer to 1.0 μm or less. come. When the film thickness of the matrix material portion is 1.0 μm or less, the interface between the scattering particles and the matrix material in the light scattering layer is reduced, and thus the scattering characteristics may be insufficient only with the light scattering layer. Moreover, since the average primary particle diameter of the scattering particles is larger on the surface of the light scattering film than the film thickness of the matrix material portion, many irregularities due to the scattering particles are generated. Therefore, when the flattening layer is selected so that the absolute value of the difference in refractive index between the scattering particles and the flattening layer is 0.05 or more, light is scattered at the interface between the flattening layer and the scattering particles. If the scattering characteristics are insufficient, the scattering characteristics can be improved.

  When non-photosensitive polyimide resin (with a refractive index of about 1.7) is selected as the matrix material, highly crosslinked acrylic particles, melamine particles, silicone particles, fluorine-containing polymer particles (with a refractive index of 1.4 to 1.5) For example, particles having a refractive index difference from the matrix material are preferably used. When a photosensitive or thermosetting (non-photosensitive) acrylic resin (refractive index of 1.5) is selected as the matrix material, melamine particles, silicone particles, fluorine-containing polymer particles (refractive index of 1.4 to 1) .45) and the like, particles having a refractive index difference from the matrix material are preferably used. When the matrix material is only acrylic resin, even if acrylic particles having a refractive index difference of less than 0.05 cannot be used because desired scattering characteristics cannot be obtained, titanium oxide cannot be used for the acrylic resin. If dispersed, the refractive index of the matrix material becomes high and the refractive index difference becomes 0.05 or more, so that it can be combined with acrylic particles.

  As a combination of the light scattering layer and the planarizing layer, it is preferable to use a non-photosensitive or photosensitive material for the light scattering layer and a photosensitive material for the planarizing layer. When the uppermost flattening layer is a photosensitive material, batch development with the lower light scattering layer can be performed, and an increase in manufacturing steps can be suppressed. For example, a non-photosensitive transparent resin containing light-scattering particles or a composition for forming a light-scattering layer made of a photosensitive transparent resin is applied onto a colored layer, dried, uncured, and uncured photosensitive transparent A light scattering layer and a planarizing layer can be processed simultaneously only in the reflective region by laminating a composition for forming a planarizing layer made of a resin, exposing and developing, and performing photolithography. In particular, when the light scattering layer is made of a non-photosensitive transparent resin, the photosensitive transparent resin of the planarization layer also serves as a photoresist, so that the light scattering layer is planarized without peeling off the photosensitive transparent resin after photolithography. It is preferable because a layered structure of layers can be manufactured and the photoresist peeling process can be shortened.

  As the alkali developer used for development, either an organic alkali developer or an inorganic alkali developer can be used. In the inorganic alkaline developer, an aqueous solution of sodium carbonate, sodium hydroxide, potassium hydroxide or the like is preferably used. In the organic alkali developer, an aqueous amine solution such as an aqueous tetramethylammonium hydroxide solution or methanolamine is preferably used. It is preferable to add a surfactant to the developer in order to increase the uniformity of development. Alkali development can be performed by methods such as dip development, shower development, and paddle development. After development, pure water washing is performed to remove the alkaline developer. In shower development, it is preferable to adjust the shower pressure so as to obtain an optimal pixel shape. When the shower pressure is weak, the resolution of the pixel decreases. If the shower pressure is strong, the pixel may peel off from the substrate. The shower pressure is preferably 0.05 to 5 MPa.

  The substrate on which the reflective film for using external light is formed may be either the color filter side substrate or the substrate facing the color filter. However, in order to fully demonstrate the effects of the present invention, it faces the color filter. It is preferable to be formed on a substrate to be formed. The color filter of the present invention exhibits its effect particularly when the reflective film has an uneven shape. The method of forming the concavo-convex reflection film is to form a concavo-convex shape using a photosensitive resin using a halftone mask, etc., and then deposit aluminum or the like into a thin film by vapor deposition or sputtering, and then photolithography Although there is a method of forming only in the reflective region by patterning using, it is not limited to this.

  The color filter of the present invention is not limited to the driving method and display method of the liquid crystal display device, and is applicable to various liquid crystal display devices such as active matrix method, passive matrix method, TN mode, STN mode, ECB mode, OCB, and VA mode. Applied. Further, the present invention can be used without being limited to the configuration of the liquid crystal display device, for example, the number of polarizing plates.

  An example of a transflective liquid crystal display device produced using the color filter of the present invention having a light scattering layer in the reflective region will be described. A transparent electrode such as an ITO film is formed on the color filter. Next, this color filter substrate and a counter substrate on which a reflective film is formed only in the reflective region, a transparent insulating film on the reflective film, and a transparent electrode such as an ITO film on the reflective film are further formed. A liquid crystal alignment film provided on a substrate and subjected to a rubbing process for liquid crystal alignment, and a spacer for maintaining a cell gap are sealed and bonded together. In addition to the reflective film and the transparent electrode, a thin film transistor (TFT) element, a thin film diode (TFD) element, a scanning line, a signal line, and the like are provided on the counter substrate, and a TFT liquid crystal display device or a TFD liquid crystal display device is provided. Can be created. Next, after injecting liquid crystal from the injection port provided in the seal portion, the injection port is sealed. Next, a module can be manufactured by mounting an IC driver or the like. An example of the liquid crystal display device thus manufactured is shown in FIG.

<Measurement method>
Refractive index: Measured using a prism coupler measuring device “PC-2000” manufactured by Metricon.
Pixel film thickness: Measured using a surface roughness meter “Surfcom 130A” manufactured by Tokyo Seimitsu Co., Ltd.
EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these.

A. Preparation of polyamic acid solution 95.1 g of 4,4′-diaminodiphenyl ether and 6.2 g of bis (3-aminopropyl) tetramethyldisiloxane were charged with 525 g of γ-butyrolactone and 220 g of N-methyl-2-pyrrolidone. 144.1 g of ′, 4,4′-biphenyltetracarboxylic dianhydride was added and reacted at 70 ° C. for 3 hours, then 3.0 g of phthalic anhydride was added, and further reacted at 70 ° C. for 2 hours. A 25% by weight polyamic acid solution (PAA) was obtained.

B. Preparation of Non-Photosensitive Light Scattering Layer Paste 16.0 g of polyamic acid solution (PAA) was diluted with 24.0 g of γ-butyrolactone, 0.6 g of the particles shown in Table 1 were added thereto, and dispersed for 30 minutes using a rotary shaker. Thus, a non-photosensitive light scattering layer paste (RPI-1, 2, 3, 4, 5, 6) was obtained. In addition, 16.0 g of a polyamic acid solution (PAA) for refractive index measurement was diluted with 24.0 g of γ-butyrolactone and dispersed for 30 minutes with a rotary shaker to obtain a refractive index measurement paste (test-1).

C. Preparation of photosensitive flattening layer paste Acrylic copolymer solution (Cyclomer P, ACA-250, 43 wt% solution manufactured by Daicel Chemical Industries, Ltd.) 7.4 g, 3.2 g of pentaerythritol tetramethacrylate as a polyfunctional monomer, light As a polymerization initiator, 28.0 g of cyclopentanone was added to 1.6 g of “Irgacure” 369 to obtain a photosensitive flattening layer paste (AC-1) having a concentration of 20% by weight.
4.1 g of acrylic copolymer solution (Daicel Chemical Industries, Ltd. Cyclomer P, ACA-250, 43 wt% solution), 1.8 g of pentaerythritol tetramethacrylate as a polyfunctional monomer, oxidation with an average primary particle size of 10 nm 28.0 g of cyclopentanone was added to 5.5 g of titanium particles and 1.6 g of “Irgacure” 369 as a photopolymerization initiator to obtain a photosensitive flattening layer paste (AC-2) having a concentration of 20 wt%.

D. Preparation of photosensitive light scattering layer paste Acrylic copolymer solution (Daicel Chemical Industries, Ltd., Cyclomer P, ACA-250, 43 wt% solution) 7.4 g, polyfunctional monomer pentaerythritol tetramethacrylate 3.2 g, light As a polymerization initiator, 28.0 g of cyclopentanone is added to 1.6 g of “Irgacure” 369, and 2.8 g of silicone particles having an average primary particle size of 2.0 μm are further added to form a photosensitive light scattering layer having a concentration of 20% by weight. Paste (RAC-1) was obtained.

E. Preparation of thermosetting (non-photosensitive) light scattering layer paste Acrylic copolymer solution (Cyclomer P, ACA-250, 43 wt% solution manufactured by Daicel Chemical Industries, Ltd.) 7.4 g, pentaerythritol tetra as a polyfunctional monomer 28.0 g of cyclopentanone is added to 3.2 g of methacrylate, and 2.8 g of silicone particles having an average primary particle size of 2.0 μm are further added to form a photosensitive light scattering layer paste having a concentration of 20% by weight (RAC-2). Got.
Acrylic copolymer solution (Daicel Chemical Industries, Ltd., Cyclomer P, ACA-250, 43 wt% solution) 3.8 g, polyfunctional monomer pentaerythritol tetramethacrylate 1.6 g, and titanium oxide having an average primary particle size of 10 nm 28.0 g of cyclopentanone is added to 5.0 g of particles, and 0.8 g of acrylic particles having an average primary particle size of 1.5 μm are added, and a photosensitive light scattering layer paste (RAC-3 having a concentration of 20% by weight) is added. )
7.4 g of acrylic copolymer solution (Cyclomer P, ACA-250, 43 wt% solution manufactured by Daicel Chemical Industries, Ltd.), 28.0 g of cyclopentanone is added to 3.2 g of pentaerythritol tetramethacrylate as a polyfunctional monomer, and 2.8 g of acrylic particles having an average primary particle size of 1.5 μm were added to obtain a photosensitive light scattering layer paste (RAC-4) having a concentration of 20% by weight.

(Measurement of refractive index)
Test-1, AC-1, and 2 were apply | coated on the silicon wafer, and the coating film with a film thickness of 2 micrometers was formed. The refractive index was measured for all coatings. The measurement results are shown in Table 2.

  In addition, Table 3 shows the refractive indexes of the silicone particles and acrylic particles which are scattering particles.

Example 1
(Create color filter)
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.

A non-photosensitive light scattering layer paste (RPI-1) was applied on the color filter with a spinner so that the thickness of the matrix material portion after heat treatment was 1.0 μm, and dried in an oven at 120 ° C. for 20 minutes. . A photosensitive flattening layer on the coating film so that the film thickness after heat treatment at the center of the pixel in the reflective region is 3.0 μm (the film thickness is from the top of the colored layer and is the sum of RPI-1). The paste (AC-1) was applied with a spinner and heat-treated in an oven at 80 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (ultraviolet intensity of 365 nm) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After the exposure, the light scattering layer and the flattening layer obtained from RPI-1 and AC-1 were developed at the same time by immersing in a developer composed of a 2.25% aqueous solution of tetramethylammonium hydroxide. After development, heat treatment was performed in an oven at 240 ° C. for 30 minutes to obtain a laminated structure of a light scattering layer and a planarizing layer only in the reflective region.
FIG. 3 schematically shows a structural cross-sectional view of the obtained color filter.

Example 2
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RPI-2.

Example 3
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.
A non-photosensitive light scattering layer paste (RPI-2) was applied on the color filter with a spinner so that the thickness of the matrix material portion after heat treatment was 0.3 μm, and dried in an oven at 120 ° C. for 20 minutes. . A photosensitive flattening layer on the coating film so that the film thickness after heat treatment at the center of the pixel in the reflective region is 1.5 μm (the film thickness is from the top of the colored layer and is the sum of RPI-2). The paste (AC-2) was applied with a spinner and heat-treated in an oven at 80 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (ultraviolet intensity of 365 nm) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After the exposure, the light scattering layer and the flattening layer obtained from RPI-2 and AC-2 were simultaneously developed by immersing in a developer composed of a 2.25% aqueous solution of tetramethylammonium hydroxide. After development, heat treatment was performed in an oven at 240 ° C. for 30 minutes to obtain a laminated structure of a light scattering layer and a planarizing layer only in the reflective region.

Example 4
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RPI-3.

Example 5
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RPI-5.

Example 6
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.
A non-photosensitive light scattering layer paste (RAC-2) was applied on the color filter with a spinner so that the thickness of the matrix material portion after heat treatment was 1.5 μm, and dried in an oven at 80 ° C. for 10 minutes. . A photosensitive flattening layer on the coating film so that the film thickness after heat treatment at the center of the pixel in the reflective region is 3.0 μm (the film thickness is from the top of the colored layer and is the sum of RAC-2). The paste (AC-1) was applied with a spinner and heat-treated in an oven at 80 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (ultraviolet intensity of 365 nm) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After the exposure, the light scattering layer and the planarizing layer obtained from RAC-2 and AC-1 were simultaneously developed by immersing in a developer composed of a 2.25% aqueous solution of tetramethylammonium hydroxide. After development, heat treatment was performed in an oven at 240 ° C. for 30 minutes to obtain a laminated structure of a light scattering layer and a planarizing layer only in the reflective region.

Example 7
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RAC-3.

Example 8
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.
A photosensitive light scattering layer paste (RAC-1) was applied on the color filter with a spinner so that the thickness of the matrix material portion after heat treatment was 1.5 μm, and dried in an oven at 90 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (ultraviolet intensity of 365 nm) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After exposure, the film was immersed in a developer composed of a 2.25% aqueous solution of tetramethylammonium hydroxide. After the development, heat treatment was performed in an oven at 240 ° C. for 30 minutes to form a light scattering layer only in the reflective region.
A photosensitive flattening layer paste (AC-1) was applied on the substrate with a spinner so that the film thickness after heat treatment was 1.5 μm, and heat-treated in an oven at 80 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was carried out at 100 mJ / cm ² (ultraviolet intensity of 365 nm). After the exposure, heat treatment was performed in an oven at 240 ° C. for 30 minutes to form a flattening layer on the entire surface of the color filter.
FIG. 4 is a schematic cross-sectional view of the obtained color filter.

Example 9
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RPI-4.

Example 10
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RPI-6.

Example 11
A color filter was produced in the same manner as in Example 3 except that the photosensitive flattening layer paste was AC-1.

Example 12
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.
On the color filter, the non-photosensitive light scattering layer paste (RPI-1) was applied with a spinner so that the film thickness of the matrix material after heat treatment was 1.3 μm, and dried in an oven at 120 ° C. for 20 minutes. . A photosensitive flattening layer on the coating film so that the film thickness after heat treatment at the center of the pixel in the reflective region is 1.5 μm (the film thickness is from the top of the colored layer and is the sum of RPI-1). The paste (AC-1) was applied with a spinner and heat-treated in an oven at 80 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (ultraviolet intensity of 365 nm) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After the exposure, the light scattering layer and the flattening layer obtained from RPI-1 and AC-1 were developed at the same time by immersing in a developer composed of a 2.25% aqueous solution of tetramethylammonium hydroxide. After development, heat treatment was performed in an oven at 240 ° C. for 30 minutes to obtain a laminated structure of a light scattering layer and a planarizing layer only in the reflective region.

Example 13
A color filter was produced in the same manner as in Example 3 except that the thickness of the laminated structure of the light scattering layer and the planarizing layer was 1.0 μm.

Example 14
A color filter was produced in the same manner as in Example 3 except that the thickness of the laminated structure of the light scattering layer and the planarizing layer was 4.0 μm.

Example 15
A color filter was produced in the same manner as in Example 1 except that the non-photosensitive light scattering layer paste was RAC-4.

Comparative Example 1
A red resist for a red colored layer is applied on a glass substrate on which a resin black matrix is patterned with a film thickness of 2.0 μm, and is patterned at a desired position by exposure and development to form a red pixel with a film thickness of 2.0 μm. Formed. Similarly, green and blue pixels were patterned to complete a color filter consisting of red, blue and green pixels.
On the color filter, a non-photosensitive light scattering layer paste (RPI-1) was applied with a spinner so that the film thickness of the matrix material after heat treatment was 1.5 μm, and dried in an oven at 120 ° C. for 20 minutes. . A positive photoresist (“OFPR-800” manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied thereon and oven dried at 90 ° C. for 10 minutes. Using a UV exposure machine “PLA-501F” manufactured by Canon Inc., exposure was performed at 100 mJ / cm ² (365 nm UV intensity) through a chromium photomask. The photomask used at this time had an opening only in the reflection region. After the exposure, the film was immersed in a developer composed of a 2.0% aqueous solution of tetramethylammonium hydroxide, and development of the photoresist and etching of the polyamic acid coating film were simultaneously performed. The photoresist layer that became unnecessary after etching was peeled off with acetone and heat-treated at 240 ° C. for 30 minutes to obtain a light scattering layer.
Table 4 shows the refractive indexes of the light scattering layer and the planarization layer obtained in Examples 1 to 15 and Comparative Example 1.

(Measurement of surface level difference)
Table 5 shows the results of measuring the level difference on the coating film surface of the laminated structure of the light scattering layer and the flattening layer obtained in Examples 1 to 15 and Comparative Example 1.

(Formation of film on color filter pixel)
On the color filters obtained in Examples 1 to 15 and Comparative Example 1, an ITO film was sputtered to a thickness of 0.14 μm.

(Production of liquid crystal display device)
Separately, after forming a TFT element on an alkali-free glass, using a halftone mask, the photosensitive resin is formed into a concavo-convex shape, aluminum is formed into a thin film by vapor deposition, and this is reflected using a photolithography method The uneven reflective film was patterned only in the use area. A substrate having a transparent insulating film on the reflective film and an ITO film transparent electrode formed thereon is prepared as a counter substrate, and an alignment film is formed on the color filter substrate and the counter substrate prepared in Examples 1 to 15 and Comparative Example 1. Was printed and rubbed for orientation. A sealing agent kneaded with a microrod was printed on one of these two substrates, and a bead spacer having a thickness of 5 μm was sprayed, and then the two substrates were bonded together. Next, TN liquid crystal (refractive index anisotropy Δn to 0.1) compatible with 4V driving was injected to close the liquid crystal injection port with a sealing agent. A liquid crystal cell into which liquid crystal was injected was sandwiched between orthogonal polarizing films to prepare a liquid crystal cell for evaluation. A liquid crystal display device was completed by mounting an IC driver or the like on the liquid crystal cell.

  The transflective liquid crystal display devices using the color filters prepared in Examples 1 to 15 and Comparative Example 1 were compared under outdoor ambient light and indoor backlight lighting conditions.

  The transflective liquid crystal display device using Comparative Example 1 does not have a flattening layer applied on the light scattering layer, so the surface level difference is large and liquid crystal alignment failure occurs. The display characteristics were poor.

  The transflective liquid crystal display devices using the color filters of Examples 1 to 8 have clear display and good display characteristics when used indoors where transmissive display is the mainstream. When used outdoors, which is the mainstream, the display was bright and free from glare and had good display characteristics. The transflective liquid crystal display devices using the color filters of Examples 9, 11, and 15 were less effective in eliminating glare than Examples 1 to 8 when used outdoors where reflective display was the mainstream. Further, the transflective liquid crystal display device using the color filters of Examples 10, 12, 13, and 14 was not as good as Comparative Example 1, but was not good display characteristics as compared with Examples 1-8. .

Schematic diagram showing the matrix material part of the light scattering layer Schematic sectional view of a transflective liquid crystal display device using a color filter with a light scattering layer formed Schematic cross-sectional view of the color filter of Example 1 Schematic cross-sectional view of the color filter of Example 8

Explanation of symbols

1: Transparent substrate 2: Black matrix 3: Light scattering layer
4: flattened layer 5: reflective region 6: transmissive region 7: pixel region 7B: blue pixel region 7G: green pixel region 7R: red pixel region 8: liquid crystal layer 9: reflective film 10: film thickness of the matrix material portion

Claims (13)

Used in transflective liquid crystal display devices that can display with reflected light and display with transmitted light, and consists of a reflective area used for display with reflected light and a transmissive area used for display with transmitted light, and has a colored layer. A color filter substrate for a transflective liquid crystal display device in which a plurality of pixels are two-dimensionally arranged on a transparent substrate, and has a light scattering layer on the colored layer in the reflective region, and the light scattering A color filter substrate for a transflective liquid crystal display device, wherein a planarizing layer is formed on the layer. 2. The color filter substrate for a transflective liquid crystal display device according to claim 1, wherein the light scattering layer is formed by dispersing particles having different refractive indexes between a matrix material and the matrix material. The color filter substrate for a transflective liquid crystal display device according to claim 1, wherein the flattening layer is formed only on the light scattering layer. 4. The color filter for a transflective liquid crystal display device according to claim 2, wherein an average primary particle diameter of particles dispersed in the light scattering layer is 1.5 μm to 3 μm. substrate. The color filter substrate for a transflective liquid crystal display device according to any one of claims 2 to 4, wherein a matrix material of the light scattering layer is non-photosensitive. The matrix material of the light scattering layer is formed of a thermosetting acrylic resin, and the planarizing layer is formed by photocuring a photosensitive resin. A color filter substrate for a transflective liquid crystal display device as described. The matrix material of the light scattering layer is formed of a non-photosensitive polyimide resin, and the planarizing layer is formed by photocuring a photosensitive resin. A color filter substrate for a transflective liquid crystal display device as described. The refractive index (n1) of the particles dispersed in the light-scattering layer, the refractive index (n2) of the matrix material of the light-scattering layer, and the refractive index (n3) of the planarizing layer have the following relationship: The color filter substrate for a transflective liquid crystal display device according to claim 2.

The color filter for a transflective liquid crystal display device according to any one of claims 1 to 8, wherein a film thickness of the laminated structure of the light scattering layer and the flattening layer is 1.5 µm or more and 3.0 µm or less. substrate. The color filter substrate for a transflective liquid crystal display device according to any one of claims 1 to 9, wherein the thickness of the matrix material portion of the light scattering layer is 1.0 µm or less. 11. The flattening layer is formed by dispersing a photosensitive acrylic resin and an inorganic powder having a refractive index higher than that of the photosensitive acrylic resin and an average primary particle diameter of 0.1 μm or less. A color filter substrate for a transflective liquid crystal display device according to any one of the above. Used in transflective liquid crystal display devices that can display with reflected light and display with transmitted light, and consists of a reflective area used for display with reflected light and a transmissive area used for display with transmitted light, and has a colored layer. A method for manufacturing a color filter substrate for a transflective liquid crystal display device in which a plurality of pixels are two-dimensionally arranged on a transparent substrate, and includes the following (A), (B), (C) and ( A process for producing a color filter for a transflective liquid crystal display device, wherein the step D) is sequentially performed.
(A) forming a pixel composed of a colored layer on a transparent substrate;
(B) applying and drying a non-photosensitive light scattering layer forming composition,
(C) a step of applying a photosensitive planarizing layer-forming composition on the non-photosensitive light scattering layer and drying it;
(D) a step of exposing and developing the substrate on which the colored layer, the light scattering layer, and the planarizing layer are laminated, and forming the light scattering layer and the planarizing layer only on the pixels in the reflective region;
A process for producing a color filter substrate for a transflective liquid crystal display device, comprising: The color filter substrate for a transflective liquid crystal display device according to claim 1, or the color filter substrate for a transflective liquid crystal display device obtained by the manufacturing method according to claim 12, and the surface is uneven only in the reflective region. A transflective liquid crystal display device in which a liquid crystal is sandwiched between drive element side substrates having a reflective layer having a shape.

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