KR101276004B1 - Liquid Crystal Display and Manufacturing Method of the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing the same to improve the response speed of the liquid crystal.

A first substrate on which the thin film transistor array is formed; A second substrate formed to face the first substrate and the cell gap therebetween and having a color filter array formed on a surface facing the first substrate; The cell gap is provided with a liquid crystal material in which carbon nanotubes and a liquid crystal are mixed.

Description

Liquid crystal display and its manufacturing method {Liquid Crystal Display and Manufacturing Method of the same}

1 is a view showing a conventional liquid crystal display device.

2A and 2B illustrate a liquid crystal display device according to the present invention.

3 is a view schematically showing a manufacturing process of a liquid crystal display according to the present invention;

4A and 4B illustrate a process of manufacturing a liquid crystal material of a liquid crystal display according to the present invention.

5A and 5B are diagrams for explaining PDLC.

6A and 6B illustrate a PDLC according to the present invention.

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

24, 172: liquid crystal 180: carbon nanotubes

174: surfactant 190, 290: liquid crystal material

272: polymer dispersed liquid crystal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same, which can improve the response speed of a liquid crystal.

The liquid crystal display displays an image by adjusting the light transmittance of the liquid crystal having dielectric anisotropy using an electric field. To this end, the liquid crystal display includes a liquid crystal display panel (hereinafter referred to as a liquid crystal panel) for displaying an image through a liquid crystal cell matrix, and a driving circuit for driving the liquid crystal panel.

Referring to FIG. 1, a conventional liquid crystal panel includes a color filter substrate 10 and a thin film transistor substrate 20 bonded to each other and a liquid crystal 24 filled in a liquid crystal space provided between two substrates 10 and 20. It consists of.

The color filter substrate 10 includes a black matrix 4, a color filter 6, and a common electrode 8 sequentially formed on the upper substrate 2. The black matrix 4 is formed in a matrix form on the upper substrate 2. This black matrix 4 divides the area of the upper substrate 2 into a plurality of cell areas in which the color filter 6 is to be formed, and prevents light interference and external light reflection between adjacent cells. The color filter 6 is formed to be divided into red (R), green (G), and blue (B) in the cell region divided by the black matrix (4) to transmit red, green, and blue light, respectively. The common electrode 8 supplies a common voltage Vcom which is a reference when driving the liquid crystal 24 to the transparent conductive layer coated on the color filter 6. In addition, an overcoat layer (not shown) may be further formed between the color filter 6 and the common electrode 8 to planarize the color filter 6.

The thin film transistor substrate 20 includes a thin film transistor 18 and a pixel electrode 22 formed in each cell region defined by the intersection of the gate line 14 and the data line 16 on the lower substrate 12. The thin film transistor 18 supplies the data signal from the data line 16 to the pixel electrode 22 in response to the gate signal from the gate line 12. The pixel electrode 22 formed of the transparent conductive layer supplies a data signal from the thin film transistor 18 to drive the liquid crystal 24.

Meanwhile, the common electrode 8 described above may not be formed on the color filter substrate 10 as shown in FIG. 1, but may be formed to be parallel to the pixel electrode 22 of the thin film transistor substrate 20.

The liquid crystal 24 having dielectric anisotropy is rotated according to the electric field formed by the data signal of the pixel electrode 22 and the common voltage Vcom of the common electrode 8 to adjust the light transmittance so that gray scales are realized.

Such a liquid crystal display has a problem in that a phenomenon in which an afterimage of a previous screen remains and a portion where an image is moved is blurred due to the response speed of the liquid crystal when displaying a moving image. In order to solve this problem, it is necessary to improve the response speed of the liquid crystal.

Accordingly, it is an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same that can improve the response speed of the liquid crystal.

In order to achieve the above object, the liquid crystal display device according to the present invention comprises: a first substrate on which a thin film transistor array is formed; A second substrate formed to face the first substrate and the cell gap therebetween and having a color filter array formed on a surface facing the first substrate; The cell gap is provided with a liquid crystal material in which carbon nanotubes and a liquid crystal are mixed.

A method of manufacturing a liquid crystal display according to the present invention includes the steps of: preparing a first substrate on which a thin film transistor array is formed and a second substrate on which a color filter array is formed; Adhering the array surfaces of the first substrate and the second substrate to face each other with a cell gap therebetween; Injecting a liquid crystal material mixed with carbon nanotubes and a liquid crystal into the cell gap.

In the preparing of the first substrate and the second substrate, an alignment layer is formed on at least one of the liquid crystal array surfaces of the first substrate and the second substrate.

The liquid crystal material includes a surfactant.

The length of the carbon nanotubes is the same as the long axis length of the liquid crystal.

The length of the carbon nanotubes is less than the cell gap.

Dispersing carbon nanotubes in the liquid crystal and surfactant before injecting the liquid crystal material into the cell gap.

The liquid crystal includes a polymer dispersed liquid crystal.

Other objects and advantages of the present invention other than the above object will be apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 2A to 4B.

In FIGS. 2A and 2B, the twisted nematic mode (hereinafter, referred to as a "TN mode"), which is most commonly applied to a liquid crystal display, is illustrated. However, the present invention is not limited to a specific mode of the liquid crystal display. Can be applied.

2A and 2B, the liquid crystal display according to the present invention has a structure in which the thin film transistor array substrate 170 and the color filter array substrate 160 are opposed to each other.

The bonded thin film transistor array substrate 170 and the color filter array substrate 160 maintain a constant cell gap by the spacer 113, and the liquid crystal 172 and the liquid crystal 172 for adjusting light transmittance according to the electric field are formed in the cell gap. In order to improve the response speed of the C), the liquid crystal material 190 including the carbon nanotubes 180 dispersed in the molecules of the liquid crystal 172 is filled.

The liquid crystal material 190 may further include a surfactant 174 so that the carbon nanotube 180 powder may be well dispersed without aggregation.

The thin film transistor array substrate 170 includes a thin film transistor (hereinafter referred to as "TFT"), a pixel electrode 116, and a lower alignment layer 138 formed on the first substrate 132.

The color filter array substrate 160 includes a black matrix 104, color filters 106, a common electrode 107, a spacer 113, and an upper alignment layer 108 sequentially formed on the second substrate 102. do.

In the color filter array substrate 160, the black matrix 104 is formed to overlap the TFT region of the first substrate 132 and the region of the gate lines and data lines (not shown), and the color filters 106 are formed. The cell region to be formed is partitioned. In addition, the black matrix 104 prevents light leakage and absorbs external light to increase contrast. The color filters 106 are formed in the cell region separated by the black matrix 104. The color filters 106 are divided into R, G, and B colors, and implement R, G, and B colors. The common electrode 107 is formed to cover the color filters 106 to supply a common voltage which is a reference when driving the liquid crystal 172. This common voltage forms a vertical electric field with the pixel voltage supplied to the pixel electrode 116 to drive the liquid crystal 172. The spacer 113 serves to maintain a cell gap between the first substrate 132 and the second substrate 102.

In the thin film transistor array substrate 170, a TFT includes a gate electrode 121 formed on the first substrate 132 along with a gate line (not shown), and the gate electrode 121 and the gate insulating film 144. And a source electrode 140 and a drain electrode 142 formed together with a data line (not shown) with the semiconductor layers 114 and 147 superposed therebetween and the semiconductor layers 114 and 147 interposed therebetween. This TFT supplies the pixel signal from the data line to the pixel electrode 116 in response to the scan signal from the gate line. The pixel electrode 116 is a transparent conductive material having a high light transmittance and contacts the drain electrode 142 of the TFT with the passivation layer 150 therebetween.

The upper and lower alignment layers 108 and 138 are formed of an alignment material such as polyimide to orient the liquid crystal 172.

Since the liquid crystal 172 has dielectric anisotropy, gray scales are realized by rotating light according to the electric field formed by the data signal of the pixel electrode 116 and the common voltage Vcom of the common electrode 107.

The carbon nanotubes 180 injected into the cell gap together with the liquid crystal 172 are dispersed in an irregular arrangement state as shown in FIG. 2A before voltage is applied between the pixel electrode 116 and the common electrode 107.

Carbon nanotubes 180 is a material in which the carbon atoms bonded by hexagonal rings form a long tube shape, the diameter of the tube is a fine molecule of nanometer (nm = 1 billionth of a meter) size. In more detail, the carbon nanotubes 180 have a planar structure in which one carbon atom is bonded to three adjacent carbon atoms to form a honeycomb shape in a spiral shape along the tube axis. The carbon nanotubes 180 are more than 100 times stronger in tensile strength and superior in flexibility, have excellent thermal conductivity as well as diamonds, have excellent electrical characteristics, and are widely known as lightweight new materials of the future. Therefore, the carbon nanotubes 180 having better electrical characteristics than the liquid crystal 172 reacts to an electric field before the liquid crystal 172 when the voltage is applied between the pixel electrode 116 and the common electrode 107 as shown in FIG. 2B. To make a regular arrangement. In addition, the carbon nanotubes 180 reacting with the electric field first improve the response speed of the liquid crystal 172 by assisting the operation of the liquid crystal 172. In addition, the regular arrangement of the carbon nanotubes 180 may further improve the arrangement state of the liquid crystal 172. As such, when the arrangement of the liquid crystal 172 is improved, the liquid crystal 172 having the improved arrangement may increase light transmittance, thereby improving display quality of the liquid crystal display.

The carbon nanotubes 180 may be synthesized and grown by a method such as laser deposition or chemical vapor deposition. As the length of the carbon nanotubes 180 grown in this manner is the same as the length of the liquid crystal 172, it is advantageous to improve the response speed and the arrangement state of the liquid crystal 172.

In addition, since the carbon nanotubes 180 are conductive, when the length of the carbon nanotubes 180 is greater than or equal to a cell gap, the carbon nanotubes 180 contact the thin film transistor array substrate 170 and the color filter array substrate 160 to short-circuit the two substrates 170 and 160. You can. Therefore, the length of the carbon nanotubes 180 is preferably formed to be less than the cell gap.

 3 to 4b are views for explaining the manufacturing method of the liquid crystal display device according to the present invention.

Referring to FIG. 3, the manufacturing process of the liquid crystal display according to the present invention is largely divided into substrate patterning (S1), substrate bonding (S2), liquid crystal material manufacturing process (S3), and liquid crystal material injection process (S4). Here, the liquid crystal material includes carbon nanotubes.

In the substrate patterning process S1, a pattern of the liquid crystal display device is formed by using a substrate from which foreign substances contaminated on the surface are removed. The substrate patterning process S1 is divided into a process of forming a thin film transistor array substrate on a first substrate and a process of forming a color filter array substrate on a second substrate.

A signal line such as a data line and a gate line is formed on the first substrate, a TFT is formed at an intersection of the data line and the gate line, and a pixel electrode is formed in the pixel region between the data line and the gate line. A color filter, a common electrode, a black matrix, and the like are formed on the substrate.

Substrate bonding process S2 includes the process of apply | coating and rubbing an alignment film on a 1st board | substrate and a 2nd board | substrate, and the process of bonding a 1st board | substrate and a 2nd board | substrate.

The liquid crystal material manufacturing process S3 is a process of dispersing the carbon nanotube 180 powder in the liquid crystal 172 before providing the liquid crystal material before performing the liquid crystal material injection process S4.

The liquid crystal material injection process S4 includes injecting a liquid crystal material prepared in advance into a cell gap between the bonded first substrate and the second substrate and sealing the liquid crystal material injection hole.

4A and 4B illustrate the process of manufacturing the liquid crystal material 190 in detail.

4A and 4B, the liquid crystal material 190 is formed by dispersing the carbon nanotubes 180 in the liquid crystal 172. The liquid crystal material 190 may further include a surfactant 174 so that the carbon nanotubes 180 may be evenly dispersed in the liquid crystal 172 without agglomeration with each other. In addition, vibration may be applied to the liquid crystal material 190 using ultrasonic waves in the manufacturing of the liquid crystal material 190 to help dispersion of the carbon nanotubes 180. The dispersion of the carbon nanotubes 180 may be performed through various methods, such as a ball mill or a three-roll mill, in addition to ultrasonic waves, depending on the conditions of the applied carbon nanotubes 180. .

The present invention having a liquid crystal material including carbon nanotubes is more effective when applied to a polymer dispersed liquid crystal display device (hereinafter referred to as "PDLC").

Unlike conventional liquid crystal display, PDLC controls the transmission of light according to the scattering intensity of light and has the advantage of realizing clear image quality anywhere in the top, bottom, left and right without polarizer. The PDLC has a cell gap thicker than the cell gap of a general liquid crystal display device because the contrast ratio is secured only when the thickness of the liquid crystal cell is thickened. Therefore, in order to increase the response speed of the liquid crystal of the PDLC filled in the relatively thick cell gap, the driving voltage of the PDLC is inevitably high. However, since the PDLC according to the present invention includes carbon nanotubes 180 having good reactivity with an electric field in the liquid crystal cell, the response speed of the PDLC liquid crystal can be increased with a low driving voltage.

5A and 5B are views for explaining PDLC, and FIGS. 6A and 6B are views for explaining a liquid crystal display including PDLC, that is, carbon nanotubes and PDLC liquid crystal molecules according to the present invention. In the drawings, the color filter substrate 160 and the thin film transistor substrate 170 are briefly illustrated.

PDLC displays information by liquid crystal molecules 272 of PDLC scattering or absorbing light incident from a light source in response to a voltage V applied to a cell gap between the color filter substrate 160 and the thin film transistor substrate 170. do. The liquid crystal molecules 272 of the PDLC are formed in a uniform structure such that a large number of liquid crystal molecular grains of several mm are dispersed in a matrix of a polymer material, and a liquid crystal is contained in a mesh-like polymer material matrix. The liquid crystal molecules 272 of the PDLC are formed by mixing a polymer material, which is cured by ultraviolet rays or heat, with a liquid crystal.

The liquid crystal molecules 272 of the PDLC are cured by applying heat or exposing ultraviolet rays, and small liquid crystal molecular grains are formed in the polymer net. In the state in which no voltage V is applied between the color filter substrate 160 and the thin film transistor substrate 170, the major axis directions of the liquid crystal molecular grains in the liquid crystal molecules 272 of the PDLC are irregular in the direction shown in FIG. 5A. Arrange. As the long axis directions of the liquid crystal molecular grains are irregularly arranged, the light irradiated onto the liquid crystal molecules 272 of the PDLC is scattered irregularly. On the other hand, when a voltage V is applied between the color filter substrate 160 and the thin film transistor substrate 170, as shown in FIG. 5B, the liquid crystal molecular grains in the liquid crystal molecules 272 of the PDLC are oriented according to the direction of the electric field. . As described above, in the state where the voltage V is applied, the light is transmitted because the PDLC liquid crystal molecules 272 are aligned in one direction and the major axis of the liquid crystal is aligned in one direction. That is, the liquid crystal molecules 272 of the PDLC are in a transmissive state.

The PDLC according to the present invention includes a liquid crystal material 290 including liquid crystal molecules 272 and carbon nanotubes 180 of the PDLC between the color filter substrate 160 and the thin film transistor substrate 170. As described above with reference to FIGS. 2A and 2B, when the voltage V is applied between the color filter substrate 160 and the thin film transistor substrate 170, the carbon nanotubes 180 are applied to the electric field before the liquid crystal molecules 272 of the PDLC. Respond to a regular array. The carbon nanotubes 180 reacting with the electric field first improve the response speed of the liquid crystal molecules 272 of the PDLC by assisting the behavior of the liquid crystal molecules 272 of the PDLC. Since the carbon nanotubes 180 help the liquid crystal molecules 272 of the PDLC, the present invention can lower the driving voltage of the liquid crystal molecules 272 of the PDLC. In addition, the PDLC according to the present invention can improve the weakness of the PDLC in which the black luminance increases before applying the voltage (V). In more detail, before the voltage V is applied, as the incident light from the light source is scattered by the liquid crystal molecules 272 of the PDLC and leaks to the outside, the black luminance may be increased. As shown in FIG. 6A, the PDLC according to the present invention absorbs light scattered by the liquid crystal molecules 272 of the PDLC so that light is leaked to the outside by the irregularly arranged carbon nanotubes 180 before applying the voltage (V). The black brightness can be lowered because it is prevented.

The method of manufacturing PDLC according to the present invention is omitted since the liquid crystal molecules contained in the liquid crystal material are the same as those described with reference to FIGS. 3 to 4B except that the polymer dispersed liquid crystal 272 is used.

As described above, the liquid crystal display device and the manufacturing method thereof according to the present invention improve the response speed of the liquid crystal by injecting carbon nanotubes having excellent electrical reaction characteristics in addition to the liquid crystal into the cell gap between the thin film transistor array substrate and the color filter array substrate. Can be. Accordingly, the present invention can improve that afterimages remain due to the slow response speed of the liquid crystal, thereby reducing display quality of the liquid crystal display.

In addition, the present invention can improve the arrangement of the liquid crystal under the influence of the arrangement state of the carbon nanotubes, since the carbon nanotubes have a regular arrangement state in response to the electrical signal. According to the present invention, the liquid crystal having an improved arrangement may increase light transmittance, thereby improving display quality of the liquid crystal display.

In addition, the present invention including the carbon nanotubes can reduce the driving voltage of the polymer dispersed liquid crystal display by applying the polymer dispersed liquid crystal display and improve the black luminance characteristics of the polymer dispersed liquid crystal display.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (13)

A first substrate on which a thin film transistor array is formed; A second substrate formed to face the first substrate and the cell gap therebetween and having a color filter array formed on a surface facing the first substrate; A liquid crystal material in which carbon nanotubes and a liquid crystal are mixed in the cell gap; The carbon nanotube has a length less than the cell gap. The method of claim 1, And an alignment layer formed on at least one of the liquid crystal array surfaces of the first substrate and the second substrate. The method of claim 1, The liquid crystal material of claim 1, further comprising a surfactant. The method of claim 1, The length of the carbon nanotubes is the same as the long axis length of the liquid crystal. delete The method of claim 1, And the liquid crystal comprises a polymer dispersed liquid crystal. Providing a first substrate on which a thin film transistor array is formed and a second substrate on which a color filter array is formed;  Adhering the array surfaces of the first substrate and the second substrate to face each other with a cell gap therebetween; Injecting a liquid crystal material mixed with carbon nanotubes and a liquid crystal into the cell gap; The length of the carbon nanotubes is less than the cell gap manufacturing method of the liquid crystal display device. The method of claim 7, wherein Preparing the first substrate and the second substrate is An alignment film is formed on at least one of the liquid crystal array surfaces of the first substrate and the second substrate. The method of claim 7, wherein And a surfactant is further included in the liquid crystal material. The method of claim 7, wherein The length of the carbon nanotubes is the same as the long axis length of the liquid crystal manufacturing method of the liquid crystal display device. delete The method of claim 9, Before injecting the liquid crystal material into the cell gap And dispersing carbon nanotubes in the liquid crystal and the surfactant. The method of claim 7, wherein The liquid crystal is a manufacturing method of a liquid crystal display device comprising a polymer dispersed liquid crystal.

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