JP4967583B2 - Color filter for transflective liquid crystal display device and transflective liquid crystal display device - Google Patents

Description

  The present invention relates to a color filter for a transmissive liquid crystal display device and a transflective liquid crystal display device including the color filter.

  As a liquid crystal panel used for a mobile phone or a digital camera, a transflective liquid crystal panel that can display a clear image both indoors and outdoors is common. The transflective liquid crystal panel has a transmissive part for displaying with backlight and a reflective part for displaying with external light. Since the external light is transmitted twice through the liquid crystal panel in the reflective part, Therefore, a lighter and lighter color is required than the color filter in the transmission part.

  As a color filter for a transflective liquid crystal panel, a six-color filter that produces R (red), G (green), and B (blue) for each of the transmissive portion and the reflective portion twice, or a through hole in the reflective portion. Although the structure is general, the former has a problem that the manufacturing process increases and the production cost increases, and the latter has a problem that the color of the reflecting portion is deteriorated as compared with the former.

  Accordingly, it is desired to develop a color filter having the same performance as a six-color filter by forming RGB in one process (total of three colors). As a technique for this, a method of forming a reflective portion using a halftone mask (see, for example, Patent Documents 1 and 2), a transparent film, and an RGB film on the transparent film to form a thin RGB film In recent years, a formation method (see, for example, Patent Document 3) has been studied.

However, in the method of forming the reflection part using the Hearton mask, if the RGB film of the reflection part is thinned aiming at high transmittance, the adhesion between the thin reflection part RGB film and the substrate decreases, and the thin reflection part RGB There is a problem that the film peels off. In addition, in the method of forming a thin RGB film on the RGB film on the transparent film, it is difficult to form a thin RGB film on the transparent film with good controllability, and when a thin RGB film is formed There is a problem that the adhesion between the RGB film and the transparent film is lowered, and the thin RGB film is peeled off.
JP 2004-258161 A JP 2006-201433 A Japanese Patent No. 3465695

  The present invention has been made under the circumstances as described above, and an object thereof is to provide a color filter for a transmissive liquid crystal display device having a reflective portion with high brightness without impairing adhesion.

In order to solve the above problems, a first aspect of the present invention is a color filter for a transflective liquid crystal display device in which red, blue and green colored pixels are formed on a transparent substrate, Each of the pixels has a transmissive portion and a reflective portion adjacent to the transmissive portion, and the transmissive portion includes a first colored resin layer formed on the transparent substrate, and the reflective portion includes The transparent layer formed on the transparent substrate and the first colored resin layer formed so as to extend from the first colored resin layer and run on the transparent layer have a thickness smaller than that of the first colored resin layer , and A second colored resin layer having a surface level higher than the surface level of the first colored resin layer, the second colored resin layer having a hole , and the green colored pixel The hole formed in the second colored resin layer is red And to provide a transflective color filter for a liquid crystal display device comprising a hole larger than that formed in the second colored resin layer of a blue color pixel.

  In such a color filter, the holes formed in the second colored resin layer can be filled with a transparent resin.

  The film thickness of the second colored resin layer is desirably 20 to 60% of the film thickness of the first colored resin layer. In particular, the thickness of the first colored resin layer is desirably 1.5 to 3.0 μm. In addition, it is desirable that the film thickness of the transparent layer of the reflective portion is 2 to 5 μm.

  According to a second aspect of the present invention, there is provided a transflective liquid crystal display device comprising the color filter described above.

  According to the present invention, the thickness of the second colored resin layer of the reflective portion is formed to be thinner than the thickness of the first colored resin layer of the transmissive portion, and the second colored resin layer of the reflective portion includes Since a hole is formed, a color filter for a transmissive liquid crystal display device is provided that can improve the brightness of the reflecting portion without impairing the adhesion and film thickness controllability of the second colored resin layer of the reflecting portion. Is done.

  In addition, the transflective liquid crystal display device provided with such a color filter can improve the brightness of the reflecting portion and display a clear image both indoors and outdoors.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view showing one pixel of a color filter for a transmissive liquid crystal display device according to a first embodiment of the present invention. In FIG. 1, a transparent resin layer 2 is formed on a transparent substrate 1. In the region where the transparent resin layer 2 is not formed on the transparent substrate 1, a first colored resin layer 3 is formed to form a transmission portion A, and the transparent resin layer 2 extends from the first colored resin layer 3. The second colored resin layer 4 is formed so as to run over, and the transparent resin layer 2 and the second colored resin layer 4 constitute the reflection portion B. A hole 5 is formed in the second colored resin layer 4 of the reflection part B.

  In the color filter shown in FIG. 1, the film thickness of the second colored resin layer 4 in the reflection part B is smaller than the film thickness of the first color resin layer 3 in the transmission part A, and preferably the first color in the transmission part A. It is 20 to 60% of the film thickness of the colored resin layer 3, and more preferably 25 to 40%. When the film thickness of the second colored resin layer 4 of the reflection part B is thicker than this range, the brightness of the reflection part B becomes low when the reflected light from the reflection part B is displayed on the screen as display light. If it is thinner than the range, the adhesion of the second colored resin layer 4 tends to be low, and the film thickness is difficult to control.

  The film thickness of the first colored resin layer 3 in the transmissive part A is preferably 1.5 to 3.0 μm. Therefore, the film thickness of the second colored resin layer 4 in the reflective part B is 20 to 20 μm. It is preferably 60%, that is, 0.3 to 1.8 μm.

  The thickness of the transparent resin layer 2 is desirably 2 to 5 μm. When the thickness of the transparent resin layer 2 is thicker than this range, the film thickness of the second colored resin layer 4 of the reflective portion B becomes thin, and the above problem is likely to occur. The film thickness of the second colored resin layer 4 of the reflection part B becomes thick, and the brightness of the reflection part B tends to decrease.

  In addition, the diameter of the hole 5 formed in the second colored resin layer 4 of the reflection portion B depends on the width of the RGB pixel, but is different from that of the conventional through hole provided in the colored resin layer of only a simple through hole. It can be a small diameter. The diameter is preferably 5 to 30 μm. When the diameter of the hole 4 is larger than the above range, the color becomes light and it becomes difficult to display clearly, and when the diameter is smaller than this range, the brightness of the reflective portion B tends to decrease.

  Further, the shape of the hole 4 includes a round shape, a square shape, a line having a certain width, and the like as viewed from above.

In this case, the diameter means a diameter in a round shape, a length of one side in a square shape, and a width in a line having a certain width.

  As described above, in the color filter for a transmissive liquid crystal display device according to the first embodiment of the present invention, the thickness of the second colored resin layer 4 of the reflective portion B is the first colored resin layer of the transmissive portion A. 3 and a hole 5 is formed in the second colored resin layer 4 of the reflective portion B, so that the colored resin layer of the reflective portion is simply formed thinly. The film thickness may be thicker than in the case of a conventional color filter, and the diameter of the hole may be smaller than in the case of a conventional color filter in which holes are simply formed in the colored resin layer of the reflective portion. Therefore, it is possible to obtain a color filter for a transmissive liquid crystal display device in which the brightness of the reflecting portion is improved without impairing the controllability of the thickness of the second colored resin layer 4 in the reflecting portion B.

  FIG. 2 is a cross-sectional view showing one pixel of a color filter for a transmissive liquid crystal display device according to the second embodiment of the present invention. This color filter has the same configuration as that of the color filter shown in FIG. 1 except that the holes 5 formed in the second colored resin layer 4 of the reflective portion B are filled with the transparent resin 6. In this color filter, since the holes 5 are filled with the transparent resin 6, the surface becomes flat and it is possible to prevent the liquid crystal alignment from being adversely affected.

  FIG. 3 is a configuration diagram schematically showing an example of a transflective liquid crystal display device according to the third embodiment of the present invention. In FIG. 3, a color filter substrate 10 and an array substrate 30 having electrodes 22 formed at predetermined positions on a transparent substrate 21 are bonded to form a cell, liquid crystal 40 is sealed, and polarizing films 50a and 50b are formed on both surfaces of the cell. The transflective liquid crystal display device according to the third embodiment of the present invention is configured.

  In the color filter substrate 10, red pixels 11 R, green pixels 11 G, and blue pixels 11 B are formed in regions separated by the black matrix 7 on the transparent substrate 1, and a transparent electrode 12 and an overcoat layer 13 are further formed. Do it. Each of the colored pixels 11R, 11G, and 11B includes a transmissive part A and a reflective part B configured as shown in FIGS.

  The transflective liquid crystal display device configured as shown in FIG. 3 improves the brightness of the reflecting portion and can display a clear image both indoors and outdoors.

  Examples of the present invention and conventional examples will be described below to specifically explain the effects of the present invention.

<Preparation of acrylic resin solution>
The reaction vessel was charged with 800.0 parts of cyclohexanone, heated while injecting nitrogen gas into the vessel, and a mixture of the monomer and the thermal polymerization initiator was added dropwise to conduct a polymerization reaction.

Styrene 60.0 parts Methacrylic acid 60.0 parts Methyl methacrylate 65.0 parts Butyl methacrylate 65.0 parts Thermal polymerization initiation scrap 10.0 parts After dripping is completed, the mixture is heated sufficiently to 2.0 parts of a thermal polymerization initiator. Was dissolved in 50.0 parts of cyclohexanone, and the reaction was further continued to obtain an acrylic resin solution.

  Cyclohexanone was added to the resin solution so that the nonvolatile content was 20.0% by weight to prepare an acrylic resin solution for the photosensitive colored resin composition. The weight average molecular weight of this acrylic resin was about 30000.

  Using the acrylic resin solution prepared as described above, three colored photosensitive colored resin compositions having the following compositions were prepared and stirred at room temperature for 3 hours, respectively.

(Photosensitive red resin composition)
40 g acrylic resin solution, 10.0 g dipentaerythritol pentaacrylate, 2.0 g 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-one, 2-methyl- 1.0 g of 1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, C.I. I. 7.0 g of Pigment Red 177, 2.0 g of pigment dispersant, and 38.0 g of 2-methoxyethanol
(Photosensitive green resin composition)
Acrylic resin solution 40.0 g, dipentaerythritol pentaacrylate 10.0 g, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-menal-1-propan-one 2.0 g, 2-methyl -1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one 1.0 g, C.I. I. Pigment Green 36 8.0 g, Pigment Dispersant 2.0 g, and 2-methoxyethanol 37.0 g
(Photosensitive blue resin composition)
40.0 g acrylic resin solution, 10.0 g dipentaerythritol pentaacrylate, 2.0 g 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-meth-1-propan-one, 2- 1.0 g of methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, C.I. I. Pigment Blue 15: 6 (6.0 g), pigment dispersant (2.0 g), and 2-methoxyethanol (39.0 g)
Example A black pigment-dispersed photosensitive resin film was formed on a transparent substrate, which was processed by a photolithography process to form a black matrix having a thickness of 1.4 μm. Thereafter, the photosensitive coloring resin composition containing no pigment dispersant was applied by spin coating and dried at 80 ° C. for 20 minutes. Next, exposure was performed through a predetermined pattern, and development was performed to form a 3.0 μm-thick transparent resin layer in a reflection portion planned region on the transparent substrate partitioned by the black matrix.

  Next, the photosensitive red resin composition was applied by spin coating and dried at 80 ° C. for 20 minutes. Then, exposure was performed through a predetermined pattern, development and post-baking, and red pixels were formed on a predetermined area partitioned by the black matrix. As shown in FIG. 1, the red pixel is formed so as to run on the transparent resin layer 2 from the transmissive portion planned area on the transparent substrate 1, and from the first colored (red) resin layer 3 on the transparent substrate 1. And a reflection part B composed of the transparent resin layer 2 and the second colored (red) resin layer 4 thereon.

  The film thickness of the first colored (red) resin layer 3 in the transmission part A is 2.0 μm, and the film thickness of the colored (red) resin layer 4 in the projection 2 of the reflection part B is 30% of that, that is, 0 .6 μm. Further, the second colored (red) resin layer 4 of the reflection part B was provided with a hole 5 having a diameter of 9 μm.

  Thereafter, the photosensitive colored resin composition is changed, and coating, exposure, and development are repeated to form green pixels and blue pixels on a transparent substrate partitioned by a black matrix, and color for a transflective liquid crystal display device A filter was obtained. The blue resin layer in the reflective portion was provided with a 9 μm diameter hole as in the red resin layer, but the 11 μm hole was provided in the green resin layer in the reflective portion.

Conventional Example 1
Except that no hole was provided in the colored resin layer of the reflective portion, and the thickness of the colored resin layer of the reflective portion was 20% of the thickness of the colored resin layer of the transmissive portion, that is, 0.4 μm. A color filter for a transflective liquid crystal display device was obtained in the same procedure.

Conventional example 2
The transparent resin layer is not formed in the reflection part planned area on the transparent substrate, the thickness of the colored resin layer is 2.0 μm in both the transmission part and the reflection part, and the diameter of the hole in the reflection part is about the red resin layer and the blue resin layer. A color filter for a transflective liquid crystal display device was obtained in the same procedure as in Example except that the thickness was 13 μm and the green resin layer was 15 μm.

  For the above color filter, the xy chromaticity, Y value, and white balance of each pixel were obtained. The results of Examples are shown in Table 1 below, the results of Conventional Example 1 are shown in Table 2 below, and the results of Conventional Example 2 are shown in Table 3 below.

The chromaticity was double pass chromaticity and the light source was D65. The area of the reflective portion used for the calculation was 769 square μm for the red pixel, 509 square μm for the green pixel, and 658 square μm for the blue pixel.

  From the results shown in Tables 1 to 3, the following is clear. That is, in the color filter according to the example in which the colored resin layer in the reflective portion is thinned by the colored resin layer being mounted on the transparent resin layer and the colored resin layer in the reflective portion is provided with a hole, as shown in Table 1 above. Furthermore, the Y value of white balance was 37.3, and the NTSC ratio was 32.5. These values are the same as the color filter (Table 2) of Conventional Example 1 in which the colored resin layer in the reflective portion is thinned to 20% of the thickness of the colored resin layer in the transmissive portion by running the colored resin layer on the transparent resin layer. It was almost the same value. Note that, as in Conventional Example 1, when the colored resin layer on the transparent resin layer is laid on the transparent resin layer, the colored resin layer in the reflective portion is reduced to 20% of the thickness of the colored resin layer in the transmissive portion. There is a possibility that the layer may be peeled off, and there is a difficulty in controlling the film thickness.

  On the other hand, in the color filter according to the conventional example 2 in which the colored resin layer of the reflective part is the same as the transmissive part and the hole is provided in the colored resin layer of the reflective part, the hole diameter is as large as 15 μm as shown in Table 3 above. However, the Y value of green was as small as 48.6, the Y value of white balance was as low as 32.6, and the NTSC ratio was significantly low as 16.7. As a result, the display is dark and light.

FIG. 3 is a cross-sectional view illustrating a configuration of a color filter substrate according to the first embodiment of the present invention. Sectional drawing which shows the structure of the color filter substrate which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the structure of the transflective liquid crystal display device which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 ... Transparent substrate, 2 ... Transparent resin layer, 3 ... 1st colored resin layer, 4 ... 2nd colored resin layer, 5 ... Hole, 6 ... Transparent resin, 7 ... Black matrix, 10 ... Color filter substrate , 11R ... red pixel, 11G ... green pixel, 11B ... blue pixel, 12 ... transparent electrode, 13 ... overcoat layer, 22 ... electrode, 30 ... array substrate, 40 ... liquid crystal, 50a, 50b ... polarizing film.

Claims (6)

A color filter for a transflective liquid crystal display device in which red, blue, and green colored pixels are formed on a transparent substrate, wherein the colored pixels are respectively a transmissive portion and a reflective portion adjacent to the transmissive portion. The transmission part is composed of a first colored resin layer formed on the transparent substrate, and the reflection part is formed of a transparent layer formed on the transparent substrate and the first colored resin. The first colored resin layer is formed so as to extend from the layer and run on the transparent layer, and has a thickness lower than that of the first colored resin layer. A hole formed in the second colored resin layer, and the hole formed in the second colored resin layer of the green colored pixel has the red color and the second colored resin layer. Formed in the second colored resin layer of the blue colored pixel Transflective liquid crystal display device for color filters, wherein the hole larger.   The color filter for a transflective liquid crystal display device according to claim 1, wherein the hole is filled with a transparent resin.   3. The transflective liquid crystal display according to claim 1, wherein a thickness of the second colored resin layer is 20 to 60% of a thickness of the colored resin layer of the first transmission portion. Color filter for equipment.   4. The color filter for a transflective liquid crystal display device according to claim 1, wherein the first colored resin layer has a thickness of 1.5 to 3.0 μm.   The color filter for a transflective liquid crystal display device according to any one of claims 1 to 4, wherein the thickness of the transparent layer of the reflecting portion is 2 to 5 µm.   A transflective liquid crystal display device comprising the color filter according to claim 1.

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