JPWO2008050638A1 - Color filter for transflective liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

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 and a reflective portion adjacent to the transmissive portion. The color filter for a transflective liquid crystal display device, wherein the thickness of the colored resin layer is 40% or less of the thickness of the colored resin layer of the transmission portion.

Description

  The present invention relates to a color filter for a transflective liquid crystal display device and a manufacturing method thereof.

  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 color filters for transflective liquid crystal panels, 6-color CF, in which RGB of the transmissive part and the reflective part are produced twice each, and a structure in which a through hole is formed in the reflective part, are generally used. The latter has a problem that the color of the reflecting portion is deteriorated as compared with the former.

  Therefore, it is desired to develop a color filter having the same performance as six-color CF by forming RGB in one process (total three colors). As a technique for that purpose, a method of forming a reflection portion using a halftone mask (see, for example, Japanese Patent Application Laid-Open Nos. 2004-258161 and 2006-201433), a transparent film, and an upper surface of the transparent film are formed. In recent years, a method of forming a thin RGB film on the RGB film (see, for example, Japanese Patent No. 3465695) has been studied.

  However, in the method of forming a thin RGB film by riding an RGB film on the transparent film, the resist material must be changed in order to reduce the film thickness of the RGB film on the transparent film depending on the size and shape of the transparent film. There is a problem.

  On the other hand, in the method of forming the reflection part using the Hearton mask, it is possible to change the exposure condition and development condition to make the RGB film of the reflection part thin, but the RGB film of the transmission part and the reflection part. When the difference in film thickness is increased, there is a disadvantage that the film thickness varies due to variations in process conditions.

  The present invention is for a transflective liquid crystal display device that is made under the circumstances as described above, does not require a change in resist material, and can reduce the variation in the thickness of the colored resin layer in the reflective portion. An object of the present invention is to provide a color filter and a manufacturing method thereof.

  According to a first aspect of the present invention, there is provided 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 reflection adjacent to the transmissive part. A color filter for a transflective liquid crystal display device, characterized in that the thickness of the colored resin layer of the reflective portion is 40% or less of the thickness of the colored resin layer of the transmissive portion Provided.

  According to a second aspect of the present invention, there is provided a color filter for a transflective liquid crystal display device in which a colored pixel is formed on a transparent substrate, wherein the colored pixel includes a transmissive part and a reflection adjacent to the transmissive part. The transmission part is made of a colored resin layer formed on the transparent substrate, and the reflection part is a transparent resin layer formed on the transparent substrate, and a colored resin layer of the transmission part A colored resin layer formed so as to extend on the transparent resin layer, and the thickness of the colored resin layer of the reflective portion is 40% or less of the thickness of the colored resin layer of the transmissive portion. There is provided a color filter for a transflective liquid crystal display device.

  According to a third aspect of the present invention, there is provided a method for producing a color filter for a transflective liquid crystal display device in which a colored pixel comprising a colored resin layer is formed on a transparent substrate, wherein the colored resin is applied to the entire surface of the transparent substrate. A step of forming a thick colored resin layer on the transmissive portion and a thin colored resin layer on the reflective portion, and exposing the colored resin layer using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion. And developing the exposed colored resin layer, removing the portion of the colored resin layer corresponding to the light-shielding portion of the photomask pattern, and reducing the thickness of the portion of the colored resin layer corresponding to the semi-light-shielding portion And a step of forming a colored resin layer in the reflective portion region corresponding to the transparent portion of the photomask pattern and a colored resin layer corresponding to the transmissive portion region. Equipment color Method for producing a filter is provided.

  According to the fourth aspect of the present invention, the transparent film has a transparent portion formed of a colored resin layer, and the transparent resin layer formed on the transparent resin layer adjacent to the transparent portion. Forming a transparent resin layer in a reflective portion forming region of the transparent substrate in a method for producing a color filter for a transflective liquid crystal display device comprising a colored pixel having a reflective portion comprising a thin colored resin layer, the transparent substrate A step of forming a colored resin layer on the entire surface of the transparent substrate, forming a thick colored resin layer on a transparent portion forming region of the transparent substrate, and forming a thin colored resin layer on the transparent resin layer; A step of exposing using a photomask pattern having a portion and a light shielding portion, and developing the exposed colored resin layer, removing a portion of the colored resin layer corresponding to the light shielding portion of the photomask pattern, and semi-light-shielding Corresponding to Reducing the film thickness of the colored resin layer, and forming the colored resin layer of the transmissive portion corresponding to the transparent portion of the photomask pattern and the colored resin layer of the reflective portion corresponding to the semi-light-shielding portion A method for manufacturing a color filter for a transflective liquid crystal display device is provided.

  According to the present invention, the colored resin layer of the reflective portion is formed to extend from the colored resin layer of the transmissive portion and run on the transparent resin layer, and is exposed and developed using a photomask pattern including a semi-light-shielding film. Therefore, it is possible to reduce the amount of reduction in the thickness of the colored resin layer in the reflecting portion, thereby reducing the variation in the thickness of the colored resin layer in the reflecting portion. Provided is a method for producing a color filter for a transflective liquid crystal display device capable of adjusting the thickness of a colored resin layer in a reflective portion without changing the resist material even if the size or shape of the transparent resin layer changes. .

It is sectional drawing which shows the structure of the color filter substrate which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the color filter substrate which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the color filter substrate which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the color filter substrate which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the structure of the transflective liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is a characteristic view which shows the transmittance | permeability characteristic of the halftone film of a photomask.

  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 transflective liquid crystal display device according to an embodiment of the present invention. In FIG. 1, a transparent resin layer 2 is formed on a transparent substrate 1. A colored resin layer 3 is formed in a region where the transparent resin layer 2 is not formed on the transparent substrate 1 to form a transmission part A, and the colored portion extends from the colored resin layer 3 and rides on the transparent resin layer 2. The resin layer 4 is formed, and the reflective portion B is configured by the transparent resin layer 2 and the colored resin layer 4.

  In the color filter shown in FIG. 1, the thickness of the colored resin layer 4 in the reflective portion B is thinner than the thickness of the colored resin layer 3 in the transmissive portion A, and is 40% of the thickness of the colored resin layer 3 in the transmissive portion A. Hereinafter, it is preferably 5 to 40%. When the thickness of the colored resin layer 4 of the reflective part B is thicker than this range, the brightness is low when the reflected light from the reflective part B is displayed on the screen as display light. It becomes difficult to control the film thickness.

  The thickness of the colored resin layer 3 in the transmissive part A is preferably 1.5 to 3.0 μm. Therefore, the thickness of the colored resin layer 4 in the reflective part B is 5 to 40%, that is, 0 It is preferably 0.07 to 1.2 μm.

  The thickness of the transparent resin layer 2 is preferably 2 to 4 μm. When the thickness of the transparent resin layer 2 is larger than this range, the thickness of the colored resin layer 4 of the reflective portion B becomes thin and the above problem is likely to occur. When the transparent resin layer 2 is thinner than this range, the reflective portion B The thickness of the colored resin layer 4 becomes thick and the brightness tends to decrease.

  The colored resin layer pattern including the thick colored resin layer 2 and the thin colored resin layer 3 as described above is formed using a photomask pattern having a transparent portion and a semi-light-shielding portion corresponding to each. . 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.

  The color filter for a transflective liquid crystal display device according to an embodiment of the present invention shown in FIG. 1 can be manufactured by a manufacturing process as shown in FIGS. 2A to 2C.

  First, as shown in FIG. 2A, after forming a black matrix (not shown) on the transparent substrate 1, the entire surface is coated with a transparent resin, exposed and developed, and the reflection of the pixel area divided by the black matrix is reflected. The transparent resin layer 2 is formed in the part forming region.

  Next, as shown in FIG. 2B, for example, a red colored resin is coated on the entire surface to form a colored resin layer 5. At this time, the thickness of the portion of the colored resin layer 5 on the transparent resin layer 2 is reduced to 30 to 70% of the thickness of the portion on the transparent substrate 1.

  Thereafter, the colored resin layer 5 is exposed using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion, and then developed to remove the portion of the colored resin layer 5 corresponding to the light-shielding portion of the photomask pattern. At the same time, the thickness of the portion corresponding to the semi-light-shielding portion is reduced. As a result, as shown in FIG. 2C, a transmissive portion A composed of the colored resin layer 3 corresponding to the transparent portion of the photomask pattern and a reflective portion B composed of the colored resin layer 4 corresponding to the semi-light-shielding portion of the photomask pattern are formed. A pixel is formed. In this case, the thickness of the colored resin layer 4 is 5 to 40% of the thickness of the colored resin layer 3.

  Such a process is repeated for green and blue pixels, and a color filter for a transflective liquid crystal display device including red, green, and blue colored pixels is obtained.

  FIG. 3 is a configuration diagram schematically showing an example of a transflective liquid crystal display device according to the second 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 second 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 7 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 portion A and a reflective portion B configured as shown in FIG.

  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 added to a solution of 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 (320 × 400 × 0.7 mm), and this was processed by a photolinography 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, the film was exposed through a predetermined pattern and developed to form a transparent resin layer having a thickness of 3.6 μm in the planned reflective area on the transparent substrate partitioned by the black matrix.

  Next, a photosensitive red resin composition (acrylic resist: manufactured by Toyo Ink Manufacturing Co., Ltd.) was applied by spin coating (time: 10 seconds, Acc: 3 seconds) at a rotation speed of 188 rpm, and dried under reduced pressure (arrival) Pressure: 1 torr) and prebaked at 50 ° C. for 30 seconds.

  And it exposed through the photomask pattern which has a transparent part, a semi-light-shielding part, and a light-shielding part, and uses the halftone film which has the transmittance | permeability characteristic as shown in FIG. 4 as a semi-light-shielding part. The exposure was performed by setting the exposure gap to 100 μm, inserting a blue plate having a thickness of 0.5 mm into the exposure machine, and cutting short wavelength bright lines. Next, development was performed with a development time of 50 seconds, and red pixels were formed on a predetermined area partitioned by the black matrix.

  That is, the part of the photosensitive red resin composition corresponding to the light shielding part of the photomask pattern was removed, and the film thickness of the part corresponding to the semi-light shielding part was reduced. As a result, as shown in FIG. 1, the transmissive portion A made of the (red) colored resin layer 3 corresponding to the transparent portion of the photomask pattern and the (red) colored resin layer 4 corresponding to the semi-light-shielding portion of the photomask pattern. A red pixel having a reflection part B made of was formed.

  As described above, a red pixel having a reflective part and a transmissive part formed by using a photomask pattern including a semi-light-shielding film, and running on the transparent resin layer from the colored resin layer of the transmissive part is formed. After that, by changing the photosensitive colored resin composition and repeating coating, exposure, and development, green pixels and blue pixels are formed on a transparent substrate partitioned by a black matrix, and for a transflective liquid crystal display device. A color filter was obtained.

In the above embodiment, the present inventors changed the exposure amount, the illuminance, and the film thickness ratio to form red pixels. 1-8 were performed. The chromaticity of the obtained red pixel is shown in Table 1 below.

  From Table 1 above, Experiment No. with a film thickness ratio exceeding 40%. 8 indicates that the Y value is low and the desired chromaticity cannot be obtained.

  Next, an experiment No. 1 in which a red pixel having a transmissive part and a reflective part is formed using a photomask having a transparent part, a semi-light-shielding part, and a light-shielding part without forming a transparent resin layer. 9 was performed. As the photosensitive red resin composition, an acrylic resist (made by Toyo Ink Manufacturing Co., Ltd.) different from the above was used.

Table 2 below shows the exposure conditions, the film thicknesses of the transmission part A and the reflection part B, the film thickness ratio, and the chromaticity.

  From Table 2 above, this experiment No. The film thickness ratio of 9 was 29.0%, but this film thickness ratio was the limit in the case where no climbing on the transparent resin layer was used.

  In addition, the film thickness is reduced only by forming the reflective part so as to extend from the colored resin layer of the transmissive part and run on the transparent resin layer, and exposure and development are performed using a photomask pattern that does not include a semi-light-shielding film. In accordance with Experiment No. 1 for forming a red pixel having a transmission part and a reflection part. 10-13 were performed. As the photosensitive red resin composition, an acrylic resist (made by Toyo Ink Manufacturing Co., Ltd.) different from the above was used.

Table 3 below shows exposure conditions, film thicknesses, film thickness ratios, and chromaticities of the transmission part A and the reflection part B.

  From Table 3 above, it can be seen that when the film thickness of the reflective portion is reduced only by running on the transparent resin layer, the Y value is low and the desired chromaticity cannot be obtained. The film thickness ratio was limited to about 35%.

  According to the above process for manufacturing a color filter for a transflective liquid crystal display device, the colored resin layer of the reflective portion is formed so as to extend from the colored resin layer of the transmissive portion and run on the transparent resin layer. Therefore, the amount of reduction in the thickness of the colored resin layer in the reflective portion can be reduced, thereby reducing the thickness of the colored resin layer in the reflective portion. It became possible to reduce the variation of the. In addition, even if the size and shape of the transparent resin layer are changed, it is possible to adjust the thickness of the colored resin layer in the reflective portion without changing the resist material.

Claims (5)

A color filter for a transflective liquid crystal display device in which colored pixels are formed on a transparent substrate, the colored pixels having a transmissive part and a reflective part adjacent to the transmissive part,
The color filter for a transflective liquid crystal display device, wherein the thickness of the colored resin layer in the reflective portion is 40% or less of the thickness of the colored resin layer in the transmissive portion. A color filter for a transflective liquid crystal display device in which colored pixels are formed on a transparent substrate, the colored pixels having a transmissive part and a reflective part adjacent to the transmissive part,
The transmissive part includes a colored resin layer formed on the transparent substrate, and the reflective part extends from the transparent resin layer formed on the transparent substrate and the colored resin layer of the transmissive part. It consists of a colored resin layer formed so as to run on the layer,
The color filter for a transflective liquid crystal display device, wherein the thickness of the colored resin layer in the reflective portion is 40% or less of the thickness of the colored resin layer in the transmissive portion.   3. The color filter for a transflective liquid crystal display device according to claim 1, wherein a thickness of the colored resin layer in the transmissive portion is 1.5 to 3.0 μm. A method for producing a color filter for a transflective liquid crystal display device, wherein a colored pixel comprising a colored resin layer is formed on a transparent substrate,
Applying a colored resin to the entire surface of the transparent substrate, forming a thick colored resin layer on the transmission portion, and forming a thin colored resin layer on the reflection portion;
A step of exposing the colored resin layer using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion; and developing the exposed colored resin layer to correspond to the light-shielding portion of the photomask pattern The colored resin layer is removed, the thickness of the colored resin layer corresponding to the semi-light-shielding portion is reduced, the colored resin layer in the reflective region corresponding to the transparent portion of the photomask pattern, and the transmission Forming a colored resin layer corresponding to the partial region. A method for producing a color filter for a transflective liquid crystal display device. A transparent portion formed of a colored resin layer on the transparent substrate, and a reflective portion formed of a colored resin layer having a thickness smaller than that of the transparent resin layer formed on the transparent resin layer adjacent to the transparent portion; In a method for producing a color filter for a transflective liquid crystal display device comprising a colored pixel having
Forming a transparent resin layer in the reflective portion forming region of the transparent substrate;
Applying a colored resin to the entire surface of the transparent substrate, forming a thick colored resin layer on a transparent portion forming region of the transparent substrate, and forming a thin colored resin layer on the transparent resin layer;
A step of exposing the colored resin layer using a photomask pattern having a transparent portion, a semi-light-shielding portion, and a light-shielding portion; and developing the exposed colored resin layer to correspond to the light-shielding portion of the photomask pattern The colored resin layer portion is removed, the thickness of the colored resin layer portion corresponding to the semi-light-shielding portion is reduced, the colored resin layer of the transmissive portion corresponding to the transparent portion of the photomask pattern, and the semi-light-shielding portion Forming a colored resin layer of the reflective portion corresponding to the above. A method for producing a color filter for a transflective liquid crystal display device.

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