JP4899773B2 - 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 transflective 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 film thickness controllability and 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 colored pixels are formed on a transparent substrate, wherein the colored pixels include a transmissive portion, A reflective portion adjacent to the transmissive portion, wherein the transmissive portion is composed of a first colored resin layer formed on the transparent substrate, and the reflective portion is a film thickness of the first colored resin layer . Of the second colored resin layer having a thickness of 25 to 50%, and the second colored resin layer has a hole with a diameter of 5 to 30 μm, and the first colored resin layer, The colored resin layer of 2 and the hole are formed using a photomask pattern having a transparent part, a semi-light-shielding part, and a light-shielding part corresponding to each of the colored resin layers, and a color filter for a transmissive liquid crystal display device is provided To do.

  In such a color filter, a transparent resin layer can be formed on the second colored resin layer so as to fill holes.

  A second aspect of the present invention is a color filter for a transflective liquid crystal display device in which colored pixels are formed on a transparent substrate, wherein the colored pixels include a transmissive part and a reflective part adjacent to the transmissive part. And the transmissive part is made of a first colored resin layer formed on the transparent substrate, and the reflective part is a second colored resin having a film thickness thinner than that of the first colored resin layer. A layer and a third colored resin layer adjacent to the first colored resin layer and having the same film thickness as the first colored resin layer, and the third colored resin layer has a hole formed therein. The first and third colored resin layers, the second colored resin layer, and the holes are formed using a photomask pattern having a corresponding transparent portion, semi-light-shielding portion, and light-shielding portion, respectively. A color filter for a transflective liquid crystal display device is provided.

In the color filter according to the second aspect , the thickness of the second colored resin layer is preferably 25 to 50% of the thickness of the first colored resin layer. In the color filters according to the first and second aspects, the film thickness of the first colored resin layer is particularly preferably 1.5 to 3.0 μm.

  According to a third 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, using the photomask pattern including the semi-light-shielding film, the thickness of the colored resin layer in the reflective portion is formed thinner than the thickness of the colored resin layer in the transmissive portion, and the colored resin in the reflective portion. Since a hole is formed in the layer, a color filter for a transmissive liquid crystal display device capable of improving the brightness of the reflecting portion without impairing the controllability of the thickness of the reflecting portion is provided.

  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 first colored resin layer 2 is formed in a transmission part formation scheduled region on the transparent substrate 1 to form a transmission part A, and the first colored resin layer 2 is adjacent to the first colored resin layer 2. The second colored resin layer 3 having a thickness smaller than that of the colored resin layer 2 is formed to constitute the reflection portion B. In addition, the hole 4 is formed in the 2nd colored resin layer 3 of a reflection part.

  In the color filter shown in FIG. 1, the film thickness of the second colored resin layer 3 in the reflective part B is thinner than the film thickness of the first colored resin layer 2 in the transmissive part A, preferably the first color in the transmissive part A. The thickness of the colored resin layer 2 is 25 to 50%. When the film thickness of the second colored resin layer 3 of the reflective part B is thicker than this range, the brightness of the reflective part B tends to be low when displaying the reflected light from the reflective part B as display light. When it is thinner than this range, it becomes difficult to control the film thickness of the second colored resin layer 3 of the reflective portion B.

  The film thickness of the first colored resin layer 2 in the transmissive part A is preferably 1.5 to 3.0 μm. Therefore, the film thickness of the second colored resin layer 3 in the reflective part B is 25 to 25 mm. It is preferably 50%, that is, 0.375 to 1.5 μm.

  In addition, the diameter of the hole 4 formed in the second colored resin layer 3 of the reflection part B depends on the width of the RGB pixel, but is different from that of a conventional through hole provided in a colored resin layer having 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.

  The colored resin layer pattern including the first colored resin layer 2 having a large thickness as described above, the second colored resin layer 3 having a small thickness, and the holes 4 formed in the second colored resin layer 3, respectively, Are formed using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion. The light-shielding portion of this photomask pattern can be made of metal chrome, and the semi-light-shielding portion can be made of ITO.

  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 3 of the reflective portion B is the first colored resin layer of the transmissive portion A. 2 and the hole 4 is formed in the second colored resin layer 3 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 reflective portion B is improved without impairing the controllability of the thickness of the second colored resin layer 3 in the reflective 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. In this color filter, the reflective portion B includes a third colored resin layer 5 having the same film thickness as the first colored resin layer 2 of the transmissive portion A as an extension of the first colored resin layer 2. 3 is formed in the colored resin layer 5. That is, the reflective portion B has the second colored resin layer 3 having a thickness smaller than that of the first colored resin layer 2 and the same thickness as the first colored resin layer 2, and the hole 6 is formed. And the third colored resin layer 5.

  Coloring composed of the first and third colored resin layers 2 and 5 having a large thickness as described above, the second colored resin layer 3 having a small thickness and the holes 6 formed in the third colored resin layer 5. The resin layer pattern can be formed using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion corresponding to each.

  FIG. 3 is a cross-sectional view showing one pixel of a color filter for a transmissive liquid crystal display device according to a third embodiment of the present invention. This color filter has the same configuration as the color filter shown in FIG. 1 except that the transparent resin layer 7 is formed on the second colored resin layer 3 so as to fill the holes 4. In this color filter, since the holes 4 are filled with the transparent resin layer 7, the surface becomes flat and it is possible to prevent the liquid crystal alignment from being adversely affected.

FIG. 4 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. 4 , the color filter substrate 10 and the array substrate 30 having the electrodes 22 formed at predetermined positions on the 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 11R, green pixels 11G, and blue pixels 11B are formed in regions separated by the black matrix 8 on the transparent substrate 1, and further, a transparent electrode 12 and an overcoat layer 13 are 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 red resin composition was applied by spin coating and dried at 80 ° C. for 20 minutes. And it exposed and developed through the photomask pattern which has a transparent part, a semi-light-shielding part, and a light-shielding part, and formed the red pixel on the predetermined area | region divided by the black matrix.

  As shown in FIG. 1, the red pixel is formed corresponding to the first (red) colored resin layer 2 constituting the transmissive portion A formed corresponding to the transparent portion of the photomask pattern and the semi-light-shielding portion. The second (red) colored resin layer 3 constituting the reflected portion B is formed, and a hole 4 is formed in the second (red) colored resin layer 3 corresponding to the light shielding portion of the photomask pattern. .

  The film thickness of the first (red) colored resin layer 2 is 2.0 μm, and the film thickness of the second (red) colored resin layer 3 is 30 times the film thickness of the first (red) colored resin layer 2. %, Ie 0.6 μm. The diameter of the hole 4 was 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 second (blue) colored resin layer of the reflecting portion was provided with a 9 μm diameter hole as in the second (red) colored resin layer, but the second (green) colored resin of the reflecting portion was provided. The layer was provided with 11 μm holes.

Conventional Example 1
No hole is provided in the second colored resin layer of the reflective part, and the film thickness of the second colored resin layer of the reflective part is 20% of the film thickness of the first colored resin layer of the transmissive part, that is, 0.4 μm. Except for this, a color filter for a transflective liquid crystal display device was obtained in the same procedure as in the example.

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 embodiment in which the second colored resin layer of the reflective portion is thinned using the photomask pattern including the semi-light-shielding film and the hole is provided in the second colored resin layer of the reflective portion, As shown in Table 1, the Y value of white balance was 37.3, and the NTSC ratio was as high as 32.5. These values correspond to the color filter of Conventional Example 1 (Table 2) in which the second colored resin layer in the reflective portion is thinned to 20% of the thickness of the colored resin layer in the transmissive portion using a photomask pattern including a semi-light-shielding film. ) And almost the same value. Note that reducing the thickness of the second colored resin layer in the reflective portion to 20% of the thickness of the first colored resin layer in the transmissive portion by using a photomask pattern including a semi-light-shielding film is the second coloring during development. There is a possibility that the resin layer may be peeled off, and there is a difficulty in controlling the film thickness.

  On the other hand, according to Conventional Example 2 in which the thickness of the second colored resin layer of the reflective portion is the same as the thickness of the first colored resin layer of the transmissive portion, and a hole is provided in the second colored resin layer of the reflective portion In the color filter, as shown in Table 3 above, even if the hole diameter is as large as 15 μm, the green Y value is as small as 48.6, the white balance Y value is as low as 32.6, and the NTSC ratio is 16 It was significantly lower at .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 color filter board | substrate which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the structure of the transflective liquid crystal display device which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,21 ... Transparent substrate, 2 ... 1st colored resin layer, 3 ... 2nd colored resin layer, 4, 6 ... Hole, 7 ... Transparent resin layer, 8 ... 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 colored pixels are formed on a transparent substrate, wherein the colored pixels have a transmissive part and a reflective part adjacent to the transmissive part, The first colored resin layer is formed on the transparent substrate, and the reflective portion is formed from a second colored resin layer having a thickness of 25 to 50% of the thickness of the first colored resin layer. A hole having a diameter of 5 to 30 μm is formed in the second colored resin layer, and the first colored resin layer, the second colored resin layer, and the hole respectively correspond to a transparent portion, A color filter for a transmissive liquid crystal display device, which is formed using a semi-light-shielding portion and a photomask pattern having a light-shielding portion.   2. The color filter for a transflective liquid crystal display device according to claim 1, wherein a transparent resin layer is formed on the second colored resin layer so as to fill holes.   A color filter for a transflective liquid crystal display device in which colored pixels are formed on a transparent substrate, wherein the colored pixels have a transmissive part and a reflective part adjacent to the transmissive part, And a first colored resin layer formed on the transparent substrate, wherein the reflective portion has a second colored resin layer having a thickness smaller than that of the first colored resin layer, and the first colored resin. A third colored resin layer adjacent to the layer and having the same film thickness as the first colored resin layer, wherein the third colored resin layer has a hole, and the first and third The translucent liquid crystal, wherein the colored resin layer, the second colored resin layer, and the hole are formed using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion corresponding to each of the colored resin layer, the second colored resin layer, and the hole Color filter for display devices. The color filter for a transflective liquid crystal display device according to claim 3 , wherein the film thickness of the second colored resin layer is 25 to 50% of the film thickness of the first colored resin layer. 5. The color filter for a transflective liquid crystal display device according to claim 1, wherein a film thickness of the first colored resin layer is 1.5 to 3.0 μm.   A transflective liquid crystal display device comprising the color filter according to claim 1.

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