KR100293431B1 - In-plane switching mode liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device of in plane switching mode is provided to maintain strong and equal switching to be formed between a data electrode and a common electrode, and to lower driving voltage by extending the data electrode and the common electrode. CONSTITUTION: On a first substrate(118) common electrode(113) gate, to be formed simultaneously with an electrode of thin film transistor, is formed and on the common electrode gate insulator film(120) is formed. Mountain shaped-walls(125) made of nonmetallic material is formed on the gate insulator film and along the shape of a wall data electrode(114) is extended to the second alignment film(124) formed on a second substrate(119). A second alignment film(123) is formed to all over the first substrate. The data electrode is equally extended to the second alignment film and the strength of the electric field is raised and therefore driving voltage can be lowered. Opening ratio is improved by making the width of the data electrode narrow.

Description

Transverse electric field liquid crystal display device {IN-PLANE SWITCHING MODE LIQUID CRYSTAL DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transverse electric field liquid crystal display device, and more particularly, to a transverse electric field liquid crystal display device in which a data electrode and / or a common electrode extend to a substrate and a substrate on which these two electrodes are formed.

Recently, in order to solve the narrow viewing angle problem which is a disadvantage of the conventional TN (twisted nematic mode) liquid crystal display, various new methods, for example, an in-plane switching mode (IPS) or an OCB method (optically Research into liquid crystal display devices employing a compensated birefrigence mode) has been actively conducted. Among these, the transverse electric field type liquid crystal display device has superior viewing angle characteristics as compared to the conventional TN type liquid crystal display device.

The transverse electric field type liquid crystal display element for the purpose of improving the viewing angle characteristic has a conventional structure as shown in FIG.

1 is a plan view of a unit pixel area of a general transverse electric field type liquid crystal display device, and includes a data line 10 and a gate line 11 arranged on a first substrate to define a pixel area, and the gate line 11 and the gate line 11. A thin film transistor arranged at the intersection of the common wiring 12 arranged in parallel with the pixel and the gate wiring 1 and the data wiring 10, and data arranged substantially parallel to the data wiring 10 in the pixel. It consists of the electrode 14 and the common electrode 13.

FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 1, in which the common electrode 13 in the pixel is formed on the first substrate 18 and connected to the common wiring, and the data electrode 14 is formed on the gate insulating film 20. It is connected to the drain electrode 17 of the thin film transistor. A first alignment layer 23 is formed over the entire substrate on the thin film transistor (not shown), the data electrode 14 and the gate insulating layer 20.

In addition, a color filter layer (not shown) including a light blocking layer (not shown) and a color filter element of R, G, and B on the first substrate 18 and the corresponding second substrate 19 to prevent light leakage. And an overcoat layer (not shown) are sequentially stacked, and a second alignment film 24 corresponding to the first alignment film 23 is formed over the substrate.

When a voltage is applied, as shown in the figure, a transverse electric field is formed between the data electrode 14 and the common electrode 13 by two electrodes, and the liquid crystal molecules 22 are arranged along the equipotential line by the transverse electric field. do. However, the electric field by the two electrodes becomes weaker toward the second substrate 19, so that the liquid crystal near the substrate is affected by a very weak electric field, and as a result, the uniform arrangement of the liquid crystal molecules becomes difficult.

For the above reason, in order to uniformly arrange the liquid crystal molecules, the distance between the two electrodes should be narrowed or the driving voltage of the liquid crystal layer should be increased. However, narrowing the gap between two electrodes is not only technically difficult, but also undesirable in view of the aperture ratio.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and provides a transverse electric field type liquid crystal display device capable of forming a uniform electric field by extending a data electrode and / or a common electrode to a substrate and a substrate on which two electrodes are formed. It aims to do it.

Another object of the present invention is to reduce the drive voltage of the liquid crystal layer by the above structure.

It is still another object of the present invention to maintain a uniform thickness of the liquid crystal layer by the two electrodes having the same height at the time of manufacturing the liquid crystal display device.

In order to achieve the above object, the transverse electric field type liquid crystal display device according to the present invention includes a first electrode and a second substrate, a gate electrode formed on the first substrate and connected to the gate wiring, and a SiN stacked on the gate electrode. _A gate insulating film made of a material such as _X or SiO _X , an amorphous silicon layer formed on the gate insulating film, an impurity amorphous silicon layer formed on the amorphous silicon layer, and an impurity amorphous silicon layer formed on the data wiring and the data electrode It consists of a source electrode and a drain electrode respectively connected. The common electrode in the pixel is formed on the first substrate and connected to the common wiring, and the data electrode is formed on the gate insulating film and connected to the drain electrode of the thin film transistor. The data electrode and / or the common electrode extend to the second substrate. When the two electrodes extend together, the heights of the two electrodes are the same. Before the formation of the data electrode and / or the common electrode, a wall for forming the two electrodes is stacked on the first substrate side, and two electrodes are formed along the shape of the wall. A protective film made of a material such as SiN _X or SiO _X is stacked on the thin film transistor, and the first alignment layer is coated on the entire substrate and the orientation direction is determined. Subsequently, a light shielding layer is formed on the second substrate corresponding to the first substrate so as to prevent light leakage near the thin film transistor, the gate wiring, the data wiring, and the common wiring, and the color filter layer, the overcoat layer, After forming the counter electrode and the second alignment layer, a liquid crystal layer having an appropriate thickness is formed between the two substrates in consideration of light transmittance and color conversion.

The first and second alignment layers may be coated with a polyimide alignment layer and subjected to rubbing to determine the alignment direction of the liquid crystal, and may be polysiloxane or polyviny1 fluoro cinnamate, for example, PVCN-F. The photoalignment film made of a polyviny1 cinnamate (PVCN) -based material may also be determined by irradiation with light. At this time, the irradiation of light can be performed once or more times using light that is polarized or not polarized.

1 is a plan view of a general transverse electric field type liquid crystal display device.

FIG. 2 is a cross-sectional view along the line A-A 'in FIG. 1 showing the arrangement of liquid crystals by electric field formation; FIG.

3 is a view according to a first embodiment of the present invention;

4 is a view according to a second embodiment of the present invention;

5 is a diagram according to a third embodiment of the present invention;

-Explanation of symbols for the main parts of the drawing-

113: common electrode 114: data electrode

118: first substrate 119: second substrate

120: gate insulating film 122: liquid crystal molecules

123: first alignment layer 124: second alignment layer

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

3 is a diagram illustrating a first embodiment of the present invention, in which a common electrode 113 formed simultaneously with a gate electrode of a thin film transistor (not shown) is formed on a first substrate 118, and a SiN is formed on the common electrode 113. _A gate insulating film 120 made of a material such as _X or SiO _X is formed, and a wall 125 made of a non-metallic material is formed in an acid shape on the gate insulating film 120, and the shape of the wall 125 is formed. Accordingly, the data electrode 114 extends to the second alignment layer 124 formed on the second substrate 119, and the first alignment layer 123 is formed over the entire area of the first substrate 118.

According to the above structure, the data electrode 114 may extend to the second alignment layer 124 in the same size to increase the intensity of the electric field formed between the common electrode 113 and the driving voltage of the liquid crystal layer. Can be reduced, and the aperture ratio can be improved by narrowing the width of the data electrode 114.

In addition, the thickness between the first substrate 118 and the second substrate 119, that is, the liquid crystal layer, may be maintained uniformly by the plurality of data electrodes 114 having a uniform height in each pixel region. As a result, no separate means, such as a spacer, for maintaining the thickness of the liquid crystal layer uniformly is necessary.

The alignment direction of the first alignment layer 123 and the second alignment layer 124 may be determined by applying a polyimide-based alignment layer and rubbing, and applying light to an optical alignment layer made of polysiloxane or PVCN-based material. You can also investigate and decide. At this time, the irradiation of light can be performed once or more times using light that is polarized or not polarized.

FIG. 4 is a view showing a second embodiment of the present invention, wherein a wall 125 made of a nonmetallic material is formed on the first substrate 118 in a narrow width, and a common electrode is formed along the shape of the wall 125. The 113 extends in the same size to the second alignment layer 124 formed on the second substrate 119, and a gate insulating layer 120 made of a material such as SiN _X or SiO _X is formed on the common electrode 113. The data electrode 114 is formed on the gate insulating layer 120, and the first alignment layer 123 is formed over the entire area of the first substrate 118.

According to the above structure, it is possible to extend the common electrode 113 to the second alignment layer 124 to increase the strength of the electric field formed between the data electrode 114 to lower the driving voltage of the liquid crystal layer. In addition, since the common electrode 113 is formed to have a narrow width, the aperture ratio may be increased.

In addition, the gap between the first substrate 118 and the second substrate 119 may be maintained uniformly by the plurality of common electrodes 113 having a uniform height in each pixel area. As a result, no separate means, such as a spacer, for maintaining the thickness of the liquid crystal layer uniformly is necessary.

The alignment directions of the first alignment layer 123 and the second alignment layer 124 may be determined in the same manner as in the first embodiment of the present invention.

FIG. 5 is a view showing a third embodiment of the present invention. A wall 125 made of a non-metallic material is formed in an acid shape on a first substrate 118, and the common electrode ( 113 extends in the same size to the second alignment layer 124 formed on the second substrate 119, and a gate insulating layer 120 made of a material such as SiN _X or SiO _X is formed on the common electrode 113. The date electrode 114 extends on the gate insulating layer 120 to the second alignment layer 124 formed on the second substrate 119 at the same height as the common electrode 113. The first alignment layer 123 is formed over the entire region of 118.

According to the above structure, the common electrode 113 and the data electrode 114 extend to the second alignment layer 124 to increase the intensity of the entire electric field while maintaining the uniformity of the electric field formed between the two electrodes. Therefore, it is possible to lower the driving voltage of the liquid crystal layer and to reduce the distortion of the liquid crystal alignment on the side surface by the first alignment film 123 formed along the acidic wall 125.

In addition, the gap between the first substrate 118 and the second wave 119 is defined by the plurality of common electrodes 113 and the data electrodes 114 having a uniform height in each pixel area. Since the thickness can be kept uniform, no separate means for maintaining the thickness of the liquid crystal layer uniformly is required.

The alignment directions of the first alignment layer 123 and the second alignment layer 124 may be determined in the same manner as in the first and second embodiments of the present invention.

In the transverse electric field type liquid crystal display device according to the first, second and third embodiments of the present invention, an electric field formed between two electrodes by extending the data electrode and / or the common electrode to the substrate on which the two electrodes are formed and the corresponding substrate. It is possible to keep the intensity of the electrode strong and uniform, whereby it is possible to reduce the driving voltage of the liquid crystal layer.

In addition, by taking the above-described structure at the time of manufacturing the liquid crystal display device, it is possible to maintain a uniform thickness of the liquid crystal layer without the need for a spacer.

Claims (11)

The first and second substrates, Data lines and gate lines arranged vertically and horizontally on the first substrate to define pixel regions; A common wiring parallel to the gate wiring and formed in the pixel region; A thin film transistor formed at an intersection point of the gate line and the common line, the thin film transistor comprising a gate electrode, a gate insulating layer, a semiconductor layer, and a source / drain electrode; A first electrode formed on the gate insulating layer; A second electrode formed on the same plane as the gate electrode, A liquid crystal layer formed between the first substrate and the second substrate, At least one of the first electrode or the second electrode extends to the second substrate facing the first substrate. The transverse electric field liquid crystal display device according to claim 1, wherein the first electrode is a data electrode and the second electrode is a common electrode. The transverse electric field liquid crystal display device according to claim 1, wherein the height of the first electrode or the second electrode is equal to the height of each neighboring first electrode or the second electrode. The method of claim 1, further comprising: common wiring arranged in the pixel region; A first alignment layer formed on the first electrode and the second electrode, and And a thin film transistor comprising a gate electrode, a gate insulating layer, a semiconductor layer, and a source / drain electrode formed at an intersection of the gate line and the data line. The transverse electric field liquid crystal display device according to claim 4, wherein the first alignment layer is a photoreactive material. The transverse electric field liquid crystal display device of claim 5, wherein the photoreactive material is a polysiloxane material or a polyvinly cinnamate (PVCN) material. The transverse electric field liquid crystal display device according to claim 4, wherein the first alignment layer is polyimide. The light blocking layer of claim 1, further comprising: a light blocking layer formed on the second substrate to prevent leakage of light; A color filter layer formed on the light shielding layer, An overcoat layer formed on the color filter layer, and And a second alignment layer formed on the color filter layer. The transverse electric field liquid crystal display device according to claim 8, wherein the second alignment layer is a photoreactive material. 10. The transverse electric field liquid crystal display device according to claim 9, wherein the photoreactive material is a polysiloxane material or a polyvinyl cinnamate (PVCN) material. 10. The transverse electric field liquid crystal display device according to claim 8, wherein the second alignment layer is polyimide.

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