KR100977383B1 - A liquid crystal display device and the fabricating method - Google Patents

Abstract

The present invention relates to a liquid crystal display and a method of manufacturing the same. A liquid crystal display device according to the present invention, comprising: a substrate; A black matrix formed by patterning on the substrate; A color filter layer formed between the patterns of the black matrix; A first compensation film formed by coating with a coatable retarder material on the color filter layer; A second compensation film formed by coating a codeable retarder material on the first compensation film; It is characterized in that it includes a back electrode formed of a transparent conductive metal film on the back surface of the substrate.

The liquid crystal display device and the manufacturing method thereof according to the present invention, in the liquid crystal display device of the IPS mode, it is possible to perform a flattening function and an optical compensation function by forming a codeable retarder material in place of the overcoating layer of the color filter.

Coatable Retarder, Uniaxial, Biaxial, Compensation Film

Description

Liquid crystal display and its manufacturing method {A LIQUID CRYSTAL DISPLAY DEVICE AND THE FABRICATING METHOD}

1A and 1B are views showing a structure without a compensation film in a transverse electric field type liquid crystal display device according to the related art, and showing a viewing angle characteristic thereof.

2a and 2b is a view showing the viewing angle characteristics when there is a compensation film in a transverse electric field type liquid crystal display device according to the prior art.

Figure 3 is a view schematically showing a method of manufacturing a phase difference compensation film using a stretching method according to the prior art.

4 is a view showing a first embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention;

5A to 5F are flowcharts of a manufacturing method of the first embodiment.

6 is a view showing a second embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention;

7 is a view showing a third embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention;

8 is a view showing a fourth embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention;                 

<Description of the symbols for the main parts of the drawings>

41, 61, 71, 81 --- Board 42, 62, 72, 82 --- Black Matrix

43, 63, 73, 83 --- Color filter layer 44, 64, 74, 84 --- First compensation film

45, 65, 76, 85 --- Second compensation film 46, 66, 75, 86 --- Back electrode

87 --- Transparent Electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same. In particular, in a liquid crystal display device in an IPS mode, a flat retarder material is formed in place of an overcoating layer of a color filter. A liquid crystal display device and a manufacturing method thereof.

Recently, with the rapid development of the information society, there is a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption. It is excellent and is actively applied to notebooks and desktop monitors.

In general, a liquid crystal display adopting a twist nematic LC has two substrates each having a field generating electrode formed thereon so that the surfaces on which the two electrodes are formed face each other, and a liquid crystal material is injected between the two substrates. Next, the liquid crystal molecules are moved by an electric field generated by applying a voltage to the two electrodes, whereby the image is expressed by the transmittance of light that varies accordingly.

On the other hand, the liquid crystal used in the liquid crystal display device usually adopts a twist nematic LC, which has a large area because the light transmittance of the gray scale display varies depending on the viewing angle. There is a limit.

Therefore, the liquid crystal cell including the twisted nematic liquid crystal is symmetrically distributed in a wide range of light transmittance at the viewing angle in the left and right directions, but the light transmittance is asymmetrically distributed in the up and down directions, so that the phase difference plate In the / downward direction, a range in which the image is inverted occurs and the viewing angle is narrowed.

On the contrary, in the plane switching mode (hereinafter referred to as 'IPS mode') using a parallel electric field, contrast, gray inversion, and color shift are compared with the twisted nematic liquid crystal mode. Viewing angle characteristics such as (color shift) can be improved.

The array substrate of the IPS mode is formed by crossing gate and data wirings on a substrate. In particular, in the IPS mode, a pixel electrode and a common electrode are the same on a pixel region P defined by crossing the gate and data wirings. The liquid crystal is formed on a plane, and the liquid crystal is operated by the horizontal electric field of the pixel electrode and the common electrode formed on the same substrate.

In this case, the liquid crystal positioned between the common electrode and the pixel electrode is arranged in the same direction by a horizontal electric field distributed between the common electrode and the pixel electrode to form one domain. In the transverse electric field method, a plurality of multi-domains exist in a single pixel region. Since it can be configured to be able to manufacture a liquid crystal display device having a wider viewing angle.

However, even in the IPS mode, there is a problem in improving color filter characteristics and viewing angle, so that the compensation film is attached to the outside of the IPS cell in order to improve the viewing angle characteristics in the IPS mode.

1A and 1B are views showing a structure without a compensation film in a conventional transverse electric field type liquid crystal display device, and showing a viewing angle characteristic thereof.

As shown in the drawing, the transverse electric field type liquid crystal display device includes a liquid crystal panel 11, an upper polarizing plate 12 attached to an upper portion of the liquid crystal panel 11, and a lower portion of the liquid crystal panel 11. An attached lower polarizing plate 13 is attached.

As described above, the structure without the compensation film in the normally black mode transverse electric field type liquid crystal display device can be seen that light leakage occurs and its viewing angle is narrow.

2A and 2B are views illustrating viewing angle characteristics when a compensation film is included in a conventional transverse electric field type liquid crystal display device.

As shown in the drawing, the horizontal electric field type liquid crystal display device includes a liquid crystal panel 21, an upper polarizing plate 22 attached to an upper portion of the liquid crystal panel 21, the liquid crystal panel 21, and the upper portion. The compensation film 24 formed between the polarizing plates 22 and the lower polarizing plate 23 attached to the lower portion of the liquid crystal panel 21 are attached.

Here, it can be seen that the viewing angle characteristic is good because the uniaxial compensation film is used as the compensation film in the liquid crystal display of the normally black mode transverse electric field method.

In more detail, liquid crystals generally have anisotropy in their molecules, and the anisotropy of liquid crystal cells or films composed of the molecules is changed by the distribution of liquid crystal molecules and the distribution of tilt angles with respect to the substrate. Have.

In addition, such characteristics become an important factor in changing the polarization of light depending on the viewing angle of the cell or film made of liquid crystal. Due to the inherent characteristics of the liquid crystal, a change in luminance and contrast ratio is caused by the viewing angles of the upper, lower, left, and right sides of the liquid crystal display, which has been the biggest disadvantage of the liquid crystal display.

In order to compensate for these disadvantages, a polarizer, a retardation film, or the like is attached to compensate for anisotropic distribution according to the viewing angle of the liquid crystal cell.

The retardation film has an anisotropy distribution as opposed to that of the liquid crystal cell, so that the retardation film is manufactured to eliminate the retardation difference of light according to the viewing angle when used with the cell.

In general, retardation film (retardation film) has a change in the phase difference with respect to the transmitted light by the polymer film and the film is stretched in a certain direction to have a birefringence by the induction of anisotropy of molecules.

On the other hand, according to the conventional method of manufacturing a retardation compensation film by using a method of stretching the polymer films in one or two axes can be obtained a desired birefringence by having an optical axis of the retardation film having an arbitrary angle with respect to the film traveling direction. .

3 is a view schematically showing a method of manufacturing a phase difference compensation film using a stretching method according to the related art. As shown in the drawing, this is a method of changing the direction of the optical axis of the retardation film by varying the stretching ratio of the left and right films.

The retardation films made at this time are specially designed retardation films because the optical axis of the retardation film must be at an arbitrary angle with the optical axis of the polarizing plate in order to be used for optical compensation, as in the LCD. Must be cut

In this method, the method of adjusting the draw ratio is mechanical, and it is not easy to adjust the angle as much as desired, and it is disadvantageous in process efficiency and foreign material management because it must be rolled one by one without bonding to the polarizer. Is generated.

The present invention provides a liquid crystal display device and a method of manufacturing the same, which can perform a flattening function and an optical compensation function by forming a codeable retarder material in place of an overcoating layer of a color filter in a liquid crystal display device in an IPS mode. There is a purpose.

In order to achieve the above object, the liquid crystal display device according to the present invention,
A substrate;
A black matrix formed by patterning on the substrate;
A color filter layer formed between the patterns of the black matrix;
A first compensation film formed by coating with a coatable retarder material on the color filter layer;
A second compensation film formed by coating with a coatable retarder material on the first compensation film;
A back electrode formed of a transparent conductive metal film on a back surface of the substrate,
Uniaxial or biaxial films may be used as the first compensation film and the second compensation film.
In addition, the liquid crystal display device according to the present invention,
A substrate;
A black matrix formed by patterning on the substrate;
A color filter layer formed between the patterns of the black matrix;
A first compensation film formed by coating a coatable retarder material on the black matrix and the color filter layer;
A back electrode formed of a transparent conductive metal film on a back surface of the substrate;
A second compensation film coated between the substrate and the back electrode by using a coatable retarder material;
Uniaxial or biaxial films may be used as the first compensation film and the second compensation film.
In addition, the liquid crystal display device according to the present invention,
A substrate;
A black matrix formed by patterning on the substrate;
A color filter layer formed between the patterns of the black matrix;
A first compensation film formed by coating with a coatable retarder material on the color filter layer;
A back electrode formed of a transparent conductive metal film on a back surface of the substrate;
A second compensation film formed on the back electrode as an attachable film type,
Uniaxial or biaxial films may be used as the first compensation film and the second compensation film.
In addition, the liquid crystal display device according to the present invention,
Patterning on a substrate in a predetermined pattern to form a black matrix;
Forming a color filter layer between the patterns on which the black matrix is formed;
Coating a coatable retarder material on the formed black matrix and the color filter layer, and then curing to form a first compensation film;
Coating a coatable retarder material on the formed first compensation film and then curing to form a second compensation film;
Uniaxial or biaxial films may be used as the first compensation film and the second compensation film.
According to the present invention, in the liquid crystal display of the IPS mode, the flat retarder material is formed in place of the overcoating layer of the color filter, thereby providing a flattening function and an optical compensation function.

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Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4 is a view showing a first embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention. As shown in the drawing, the color filter of the transverse electric field type liquid crystal display device according to the present invention comprises: a substrate 41; A black matrix 42 formed by patterning the substrate 41; A color filter layer 43 formed between the patterns of the black matrix 42; A first compensation film 44 formed on the color filter layer 43 by coating with a coatable retarder material; A second compensation film 45 formed on the first compensation film 44 by being coated with a codeable retarder material; And a back electrode 46 formed of a transparent conductive metal film on the back surface of the substrate 41.                     

The back electrode 46 serves to block static electricity applied from the outside.

In more detail, when the liquid crystal panel contacts an externally charged object, charging of the color filter substrate affects the arrangement state of the liquid crystal molecules under the color filter substrate. The back electrode 46 is formed of a transparent conductive metal layer such as indium-tin-oxide to block the static electricity.

The first compensation film 44 and the second compensation film 45 are formed on the color filter layer 43 by using a coatable uniaxial or biaxial material instead of the overcoat layer, thereby making the flattening function and It will function as an optical compensation film.

Uniaxiality and biaxiality of the first and second compensation films 44 and 45 are determined according to whether nx and ny are the same when the refractive indices in the x, y and z directions of the Cartesian coordinate system are nx, ny and nz, respectively. do.

That is, uniaxiality is when the refractive indices of the two directions are the same and their magnitudes are different from the other directions. In addition, when all three directions have refractive indices of different sizes, it is referred to as biaxiality.

Compensation films using uniaxial refractive anisotropes generally used are arranged such that the major axis of the ellipsoid is parallel or perpendicular to the film surface.

5A to 5F are flowcharts of a manufacturing method of the first embodiment. As shown in FIG. 5A, a black film 42 is formed by depositing a metal film or a resin material on the transparent insulating substrate 41.                     

More specifically, a photosensitive film made of carbon black, titanium oxide, or the like having light shielding property is applied onto the transparent substrate 41, and the photosensitive film is exposed to a predetermined pattern using a mask. Then, the photosensitive film is developed in accordance with the exposed pattern, and the developed photosensitive film is cured to form a BM (Black Matrix: BM) 42.

Subsequently, as shown in FIG. 5B, the color filter layers 43 of red color R, green color G, and blue color B are sequentially formed on the formed black matrix 42. Perform.

In more detail, a photosensitive film made of an azo red pigment or the like is coated on the transparent substrate 41 on which the BM 42 is formed, and the photosensitive film is exposed to a predetermined pattern using a mask.

Then, the photosensitive film is developed in accordance with the exposed pattern, and the developed photosensitive film is cured to form a red color (hereinafter referred to as R color).

Subsequently, a photosensitive film made of protarocyanine-based green pigment or the like is applied onto the transparent substrate on which the red collar is formed, and the photosensitive film is exposed to a predetermined pattern using a mask. Then, the photosensitive film is developed in accordance with the exposed pattern, and the developed photosensitive film is cured to form a green color (hereinafter referred to as G color).

Subsequently, a photoresist film made of phthalocyanine-based blue pigment or the like is cured on the transparent substrate on which the green color is formed to form a blue color (hereinafter referred to as B color) to complete the color filter layer 43.

Next, as shown in FIG. 5C, a first compensation film 44 is formed to protect the colored pattern of the formed color filter layer 43 and to planarize and optically compensate the black matrix 42. Done.

In more detail, the first compensation film 44 coats the photocurable liquid crystal with a coatable retarder material. Dissolve the curable nematic liquid crystal material and photoinitiator (IG184, Ciba-Geigy) 5 w% in 3-penthanon to prepare a solution so that the concentration is 10 wt% or more, especially 15-30 w%. Is carried out.

In the liquid crystal film prepared as described above, since the directions of the nematic liquid crystal molecules are all arranged in the same direction as the alignment direction of the photoalignment film, the refractive index distribution of the film is the same as the refractive index distribution of the liquid crystal molecules.

Meanwhile, the first compensation film 44 may use a C-plate of a uniaxial film or a biaxial film.

As shown in FIG. 5D, the coated substrate is dried at 70 ° C. or higher, especially 75 to 90 ° C., and then cured the curable nematic liquid crystal using non-polarized ultraviolet light or ion beam. To fix the film.

Next, as shown in FIG. 5E, a second compensation film 45 is formed on the formed first compensation film 44.

In this case, the second compensation film 45 is formed in the same manner as the first compensation film 44 is formed in FIGS. 5C and 5D.

In addition, the second compensation film 45 may form an A-plate of a uniaxial or biaxial film.                     

As shown in FIG. 5F, ITO (transparent electrode material having good permeability and conductivity and excellent chemical and thermal stability is formed on the back surface of the substrate on which the first compensation film 44 and the second compensation film 45 are formed. Indium Tin Oxide) is deposited on the entire surface of the substrate by sputtering to form the back electrode 46.

The back electrode 46 serves to block static electricity applied from the outside.

In more detail, when the liquid crystal panel 41 contacts an externally charged object, charging of the color filter substrate affects the arrangement state of liquid crystal molecules positioned under the color filter substrate.

This acts as a factor of deteriorating the image quality because the amount of light passing through the liquid crystal is not controlled by the data voltage.

Therefore, the back electrode 46 is formed on the rear surface of the color filter substrate in order to prevent a decrease in image quality due to static electricity.

6 is a view showing a second embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention. As shown in the drawing, the color filter of the transverse electric field type liquid crystal display device according to the present invention comprises: a substrate 61; A black matrix 62 formed by patterning the substrate 61; A color filter layer 63 formed between the patterns of the black matrix 62; A first compensation film 64 formed on the black matrix 62 and the color filter layer 63 by coating with a coatable retarder material; A second compensation film 65 coated on the back surface of the substrate 61 using a coatable retarder material; And a back electrode 66 formed of a transparent conductive metal film on the second compensation film 65.

Here, a detailed description of the manufacturing method of the second embodiment will be omitted with reference to the manufacturing method of the first embodiment.

The first compensation film 64 is formed on the black matrix 62 and the color filter layer 63 to provide a planarization function and an optical compensation function in place of the overcoat layer.

The second compensation film 65 is formed by a coating method such as forming the first compensation film 64.

7 is a view showing a third embodiment of the structure of the color filter substrate of the transverse electric field type liquid crystal display device according to the present invention. As shown therein, the substrate 71; A black matrix 72 formed by patterning the substrate 71; A color filter layer 73 formed between the patterns of the black matrix 72; A first compensation film 74 formed on the color filter layer 73 by coating with a coatable retarder material; A back electrode 75 formed of a transparent conductive metal film on the back surface of the substrate 71; It comprises a second compensation film 76 formed on the back electrode 75 of the attachable film type.

Here, a detailed description of the manufacturing method of the third embodiment will be omitted with reference to the manufacturing method of the first embodiment.

The first compensation film 74 is formed in a cell by a coating process, and the second compensation film 76 is formed as an adhesive film.

In this case, when the C-plate having a phase difference of 0 mm on the front surface is applied to the first compensation film 74, the phase difference due to the step difference of the color filter layer does not occur, so it is preferable to replace the overcoat layer.

In addition, the C-plate is excellent in orientation even without an alignment layer, thereby simplifying the manufacturing process of the coatable compensation film.

8 is a view showing a fourth embodiment of the structure of a color filter substrate of a transverse electric field type liquid crystal display device according to the present invention. As shown therein, the color filter of the transverse electric field type liquid crystal display device according to the present invention comprises: a substrate 81; A black matrix 82 formed by patterning the substrate 81; A color filter layer 83 formed between the patterns of the black matrix 82; A first compensation film 84 formed on the color filter layer 83 by coating with a coatable retarder material; A second compensation film 85 formed by coating a codeable retarder material on the first compensation film 84; A back electrode 86 formed of a transparent conductive metal film on the back surface of the substrate 81; It comprises a transparent electrode 87 formed of a transparent conductive film on the second compensation film (85).

Here, a detailed description of the manufacturing method of the fourth embodiment will be omitted with reference to the manufacturing method of the first embodiment.

In the fourth embodiment, the transparent conductive film is formed on the second compensation film 86 in the structure of the first embodiment to solve the reliability problem that may occur when the liquid crystal contacts.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the liquid crystal display device and the manufacturing method thereof according to the present invention provide a flattening function and an optical compensation function by forming a codeable retarder material in place of the overcoating layer of the color filter in the liquid crystal display device of the IPS mode. can do.

Claims (12)

A substrate; A black matrix formed by patterning on the substrate; A color filter layer formed between the patterns of the black matrix; A first compensation film formed by coating with a coatable retarder material on the color filter layer; A second compensation film formed by coating with a coatable retarder material on the first compensation film; A back electrode formed of a transparent conductive metal film on a back surface of the substrate, A uniaxial or biaxial film is applied to the first compensation film and the second compensation film. The method of claim 1, And forming a transparent electrode on the second compensation film as a transparent conductive film. A substrate; A black matrix formed by patterning on the substrate; A color filter layer formed between the patterns of the black matrix; A first compensation film formed by coating a coatable retarder material on the black matrix and the color filter layer; A back electrode formed of a transparent conductive metal film on a back surface of the substrate; A second compensation film coated between the substrate and the back electrode by using a coatable retarder material; A uniaxial or biaxial film is applied to the first compensation film and the second compensation film. A substrate; A black matrix formed by patterning on the substrate; A color filter layer formed between the patterns of the black matrix; A first compensation film formed by coating with a coatable retarder material on the color filter layer; A back electrode formed of a transparent conductive metal film on a back surface of the substrate; A second compensation film formed on the back electrode as an attachable film type, A uniaxial or biaxial film is applied to the first compensation film and the second compensation film. The method according to claim 3 or 4, And forming a transparent electrode on the first compensation film as a transparent conductive film. delete The method according to claim 1, 3 or 4, The C-plate is applied to the first compensation film. The method according to claim 1, 3 or 4, An A-plate is applied to the second compensation film. Patterning on a substrate in a predetermined pattern to form a black matrix; Forming a color filter layer between the patterns on which the black matrix is formed; Coating a coatable retarder material on the formed black matrix and the color filter layer, and then curing to form a first compensation film; Coating a coatable retarder material on the formed first compensation film and then curing to form a second compensation film; A uniaxial or biaxial film is applied to the first compensation film and the second compensation film. The method of claim 9, And forming a bottom electrode by depositing a transparent conductive material on the back surface of the substrate after the forming of the second compensation film. delete The method of claim 9, C-plate is applied as the first compensation film, and A-plate is applied as the second compensation film.

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