KR20050059398A - Fringe field switching mode liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

According to the FFS mode liquid crystal display according to the present invention and a method of manufacturing the same, the first electrode of the flat form in which the electrode forming the transverse electric field is formed to correspond to the pixel region, and the circular electrode structure at the position overlapping the first electrode Since the branch is composed of the second electrode, the opening area between the first and second electrodes has a circular structure, so that the liquid crystal directors are the same in all directions, thereby improving the viewing angle, and applying the square pixel structure to improve the aperture ratio. In addition, the overlapping area with the black matrix is reduced, which may have an advantage of minimizing the luminance difference that may occur in each product at the time of misalignment.

Description

Fringe field switching mode liquid crystal display device and method for manufacturing the same

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 having a high transmittance and a high opening ratio, and a manufacturing method thereof.

Recently, liquid crystal displays have been spotlighted as next-generation advanced display devices with low power consumption, good portability, technology-intensive, and high added value.

The liquid crystal display device is formed by injecting liquid crystal between two substrates on which transparent electrodes are formed, and placing upper and lower polarizers outside the upper and lower substrates, and changing image polarization characteristics according to the anisotropy of the liquid crystal molecules. It corresponds to the non-light emitting element obtained.

Currently, an active matrix liquid crystal display (AM-LCD), in which thin film transistors (TFTs), which are switching elements that open and close each pixel, is disposed for each pixel, has an excellent resolution and video performance. This has led to widespread use in applications such as flat panel television systems or high-information monitors for portable computers.

However, TN (Twisted Nematic) display mode, which is a typical liquid crystal display device, has fundamental problems such as narrow viewing angle characteristics and late response characteristics, especially late response characteristics in gray scale operation.

In order to solve this problem, various new concepts of the liquid crystal display device have been proposed. For example, one method uses a multi-domain TN structure in which one pixel is divided into several subpixels, and the other method uses an OCB (Optically Compensated birefringence) mode that compensates for the physical properties of liquid crystal molecules. will be. However, the multi-domain method is complicated in forming a multi-domain, and there is a limit in improving the viewing angle. In addition, the OCB mode has excellent electro-optical performance in terms of viewing angle characteristics and response speed, but has a disadvantage in that it is difficult to stably control and maintain the liquid crystal by a bias voltage.

Recently, as part of a new display mode, an in plane switching mode mode in which electrodes for driving liquid crystal molecules are all formed on the same substrate has been proposed.

1 is a view illustrating a driving principle of a general transverse electric field type liquid crystal display device.

As illustrated, the upper substrate 10, which is a color filter substrate, and the lower substrate 20, which is an array substrate, are spaced apart from each other, and the liquid crystal layer 30 is disposed between the upper substrate 10 and the lower substrate 20. In this interposed structure, both the common electrode 22 and the pixel electrode 24 are formed on the inner surface of the lower substrate 20.

The liquid crystal layer 30 is operated by the horizontal electric field 26 of the common electrode 22 and the pixel electrode 24, and the viewing angle is widened because the liquid crystal molecules in the liquid crystal layer 30 move by the horizontal electric field. It becomes

For example, when viewed from the front, the transverse electric field type liquid crystal display may be visible in a range of about 80 to 85 ° in the up / down / left / right directions.

Hereinafter, an electrode arrangement structure of a general transverse electric field type liquid crystal display array substrate will be described in detail with reference to the accompanying drawings.

2 is a schematic plan view of an array substrate for a general transverse electric field type liquid crystal display device.

As shown, the gate wiring 40 and the data wiring 42 are formed to cross each other, and the thin film transistor T is formed at the intersection of the gate wiring 40 and the data wiring 42. An intersection area of the gate line 40 and the data line 42 is defined as the pixel area P. FIG.

The common wiring 44 is formed to be spaced apart from the gate wiring 40 by a predetermined distance, and in the common wiring 44 positioned in the pixel region P, a plurality of common electrodes are formed in a direction parallel to the data wiring 42. 46 is forked. The first lead wire 48 is formed to be connected to the thin film transistor T. In the first lead wire 48, a plurality of common electrodes 46 and the common electrode 46 are staggered from each other at intervals between the common electrodes 46. The pixel electrode 50 is branched.

A second lead wire 52 is formed at a position where the ends of the pixel electrodes 50 are connected and overlap the common wire 44. An overlapped area of the common wire 44 and the second lead wire 52 forms a storage capacitance C _ST in a state where an insulator (not shown) is interposed therebetween.

The separation interval between the common electrode 46 and the pixel electrode 50 corresponds to a substantially opening region II for driving the liquid crystal by a transverse electric field. In this figure, a four-block structure having four opening regions II is shown. An example is shown. That is, the structure in which three common electrodes 46 and two pixel electrodes 50 are alternately arranged for each pixel area P is illustrated.

For convenience of description, the common electrode 46 positioned adjacent to the data line 42 includes the first common electrode 46a and the common electrode 46 positioned inside the pixel region P includes the second common electrode ( 46b), the first common electrode 46a located at the outer side of the first and second common electrodes 46a and 46b is a poor image quality occurring between the data line 42 and the pixel electrode 50. For the purpose of minimizing cross talk and preventing light leakage, the opening ratio should be lower than that of the second common electrode 46b.

In order to improve the aperture ratio and transmittance of the transverse electric field type liquid crystal display, a fringe field switching mode (hereinafter, abbreviated to FFS mode) has been proposed.

The FFS mode liquid crystal display device has a slit corresponding to a structure in which a flat common electrode and a rod-shaped pattern corresponding to a kind of island pattern structure corresponding to a pixel region are formed to be spaced apart from each other. (Slit) pixel electrode has a structure in which the insulator is interposed so that the transverse electric field is formed at several intervals different from the IPS mode, so the transverse electric field is strong, and the transverse electric field to the liquid crystal molecules on the electrode There is an advantage that can be arranged by. In addition, since it has a 2 ITO structure, the white luminance is increased to increase the aperture ratio.

Hereinafter, an electrode arrangement structure of a general FFS mode liquid crystal display device will be described in detail with reference to the accompanying drawings.

3A and 3B are views of a general FFS mode liquid crystal display device, FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view showing a cross section taken along the cutting line " IIIb-IIIb " FIG. 3A illustrates a plan view of an array substrate for an FFS mode liquid crystal display device, and FIG. 3B illustrates a cross-sectional structure of a liquid crystal display device including a liquid crystal layer based on the cut region.

3A, the gate wiring 62 and the data wiring 78 are formed to cross each other, the thin film transistor T is formed at the intersection of the gate wiring 62 and the data wiring 78, and the gate wiring is formed. An intersection area of the 62 and data lines 78 is defined as the pixel area P. FIG. In the pixel region P, a plurality of pixel electrodes 82 connected to the thin film transistor T and spaced apart from each other, and a common electrode 68 are formed in an area covering the plurality of pixel electrodes 82.

In more detail, the thin film transistor T includes a gate electrode 64, a semiconductor layer 72, a source electrode 74, and a drain electrode 76, and is connected to the drain electrode 76 to form a first electrode. The lead wire 84 is formed, and the above-described plurality of pixel electrodes 82 are branched from the first lead wire 84, and the ends of the pixel electrodes 82 are connected by the second lead wires 86. It is.

The common electrode 68 for each pixel region P is connected to the common wire 66 spaced apart from each other in the same direction as the gate wire 62.

The common electrode 68 and the pixel electrode 82 are made of a transparent conductive material in different processes, the common wiring 66 is made of the same material in the same process as the gate wiring 62, The common wire 66 and the common electrode 68 are connected in a manner of being connected to each other, and have a structure in which the pixel electrode 82 is disposed on the common electrode 68 in a state where an insulator is not shown.

Hereinafter, an operation characteristic of the FFS mode liquid crystal display device will be described with reference to the cross-sectional structure of FIG. 3A.

In FIG. 3B, a flat common electrode 68 is formed on the first substrate 60, and a first insulating layer 70 is formed in an area covering the common electrode 68. A plurality of slit-shaped pixel electrodes 82 are formed on the common electrode 68 on the insulating layer 70 so as to be spaced apart from each other, and the first alignment layer 88 is formed in an area covering the pixel electrodes 82. ) Is formed.

The second substrate 90 is disposed to face the first substrate 60, and the color filter layer 92 and the second alignment layer 94 are sequentially formed below the second substrate 90. The liquid crystal layer 96 is interposed between the first and second alignment layers 88 and 94.

The operating principle of the FFS mode will be described in more detail. Initially, the liquid crystal between the electrode and the electrode is first rotated in parallel with the substrate by the side electric field, and after a certain time, the vertical and side electric fields and the liquid The liquid crystal molecules on the electrode rotate by the elastic force. That is, since light is transmitted from all surfaces on the electrode, the transmittance is high. In addition, since the degree of rotation of the liquid crystal in one pixel is different, the degree of color loss is reduced by the self-compensation effect.

When the transverse electric field electrode is formed of a stripe pattern, an orientation direction is made in a direction inclined by about 60 ° with respect to 0 ° in order to form a transverse electric field when voltage is applied, so that the transverse electric field is inclined as compared with the polarization axis direction of the polarizing plate. In addition, there is a problem that the viewing angle range is non-uniform, and even in the case of the stripe pattern, the alignment direction is mostly made in the 90 ° to 270 ° direction, and the polarization axis directions of the polarizers are 0 ° and 90 ° to be perpendicular to each other at 45 °. , The viewing angle characteristic is reduced in the 135 ° direction.

In addition, since there is a color shift difference for each angle in all directions, there is a problem that the viewing angle characteristics are deteriorated.

In order to solve this problem, it is an object of the present invention to provide an FFS mode liquid crystal display device and a method of manufacturing the same that can improve the viewing angle by minimizing the color shift phenomenon.

To this end, in the present invention, the liquid crystal is driven by a transverse electric field using a first electrode formed in a flat shape at a position corresponding to the pixel region and a second electrode formed in a circular structure at a position overlapping with the first electrode. do.

In order to achieve the above object, in a first aspect of the present invention, there is provided a semiconductor device comprising: a gate wiring formed in a first direction on a first substrate; A data line formed in a second direction crossing the first direction; A common wiring formed to be spaced apart from the gate wiring in the first direction; A common electrode defined by the pixel area, the intersection area of the gate line and the data line, branched from the common line and formed in a flat shape corresponding to the pixel area; A thin film transistor formed at an intersection point of the gate line and the data line; A lead wire connected to the thin film transistor; A pixel electrode branched from the lead wire and formed in a circular structure in an area overlapping the common electrode with an insulator interposed therebetween; A second substrate disposed to face the first substrate; And a liquid crystal layer interposed between the first and second substrates, wherein the common electrode and the pixel electrode are made of a transparent conductive material, and the pixel electrode is formed of at least two patterns, and is spaced apart from the pixel electrode pattern. And a liquid crystal display (FFS) mode liquid crystal display device which drives liquid crystal molecules of the liquid crystal layer by a transverse electric field in a region including an overlapping region between the common electrode and the pixel electrode.

According to a second aspect of the present invention, there is provided a semiconductor device comprising: a gate wiring formed on a first substrate in a first direction; A data line formed in a second direction crossing the first direction; A common wiring formed to be spaced apart from the gate wiring in the first direction; A common electrode defined by the pixel area, wherein the intersection area between the gate line and the data line is defined as a pixel area, and has a circular structure branched from the common wire to correspond to the pixel area; A thin film transistor formed at an intersection point of the gate line and the data line; A pixel electrode connected to the thin film transistor and formed in a flat shape in an area overlapping the common electrode with an insulator interposed therebetween; A second substrate disposed to face the first substrate; And a liquid crystal layer interposed between the first and second substrates, wherein the common electrode and the pixel electrode are made of a transparent conductive material, and the common electrode is formed of at least two patterns, and is spaced apart from the common electrode pattern. And a liquid crystal display (FFS) mode liquid crystal display device which drives liquid crystal molecules of the liquid crystal layer by a transverse electric field in a region including an overlapping region between the common electrode and the pixel electrode.

The pixel electrode is formed of a plurality of patterns having the same center portion and arranged outwardly from the inside, and the pixel electrode has a structure in which the first to third pixel electrode patterns are sequentially arranged from the center portion to the outside. do.

The common electrode according to the second aspect may include a first common electrode pattern positioned in an area surrounding the edge of the pixel region and having a circular open portion, and a second circular band structure inside the first common electrode pattern. It characterized in that it comprises a common electrode pattern.

An overlapping region between the common electrode and the pixel electrode according to the first and second features may include a non-pixel region including an open region that forms a storage capacitor in a state where an insulator is not shown and exposes a main region of the pixel region. And an area covering the edge of the common electrode is an area covered by the black matrix, and the open part has a circular structure.

The pixel electrode according to the first aspect is characterized in that the snail structure.

The common electrode according to the second feature has a cochlear structure, and the common electrode has the cochlear open part and is positioned in an area surrounding an edge of the pixel area.

The pixel region according to the first and second features has a square structure, and one pixel region is formed of one subpixel, and four colors of red, green, blue, and white four subpixels constitute one pixel. The pixel electrode has a pixel electrode, and a capacitor electrode positioned to overlap a predetermined region with a front gate line is formed in the pixel electrode, and an overlapping region between the capacitor electrode and the gate line forms another storage capacitor.

The thin film transistor according to the first and second features may include a gate electrode branched from the gate line, a semiconductor layer positioned to overlap the gate electrode, a source electrode branched from the data line, and a distance from the source electrode. Characterized in that it consists of a drain electrode positioned to be.

The pixel electrode according to the first feature is connected to the thin film transistor through a lead wire.

In a third aspect of the invention, there is provided a method, comprising: forming a gate wiring on a substrate in a first direction; Forming a data line in a second direction crossing the first direction, and forming a thin film transistor at an intersection point of the gate line and the data line; Forming a first FFS (Fringe Field Switching) electrode having a flat pattern on the thin film transistor with an insulator interposed therebetween; And forming a second FFS (Fringe Field Switching) electrode having a circular structure and overlapping the first FFS electrode with another insulator interposed therebetween, wherein the first and second FFS electrodes are transparent. A method of manufacturing an FFS mode liquid crystal display device made of a conductive material is provided.

The first FFS electrode is a common electrode, and the forming of the common electrode may further include forming a common wiring connected to the common electrode and spaced apart from the gate wiring in the first direction. The second FFS electrode may be a pixel electrode, and the pixel electrode may be connected to the thin film transistor, and the forming of the pixel electrode may include a plurality of centers having the same center and a circular band structure from the inside out. And forming a plurality of pixel electrode patterns in order with a predetermined interval therebetween, wherein the thin film transistor includes a gate electrode, a source electrode, and a drain electrode, and the two insulators partially expose the drain electrode. A hole having a hole, and the pixel electrode is formed through the drain contact hole. Characterized in that connected to the drain electrode of the register.

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

4A and 4B are views illustrating a pattern structure of an FFS mode circular electrode according to the present invention. FIG. 4A is a view illustrating driving characteristics of liquid crystal molecules for each domain, and FIG. 4B is a diagram of a graph of a transmission-voltage (TV) curve. For example, a structure in which transverse field electrodes (hereinafter, abbreviated as circular electrodes) of circular band structures are arranged in order from the inner side to the same center may be provided as an example.

According to the circular electrode (CE) structure of FIG. 4A, a multi-domain structure including four domains D1, D2, D3, and D4 defined as regions having different arrangements of liquid crystal molecules 110 is provided. The liquid crystal molecules 110 for each domain are arranged in the direction of 90 kPa to 270 kPa without domain classification when no voltage is applied along the rubbing direction, and is horizontal to the circular electrode 110 by applying a transverse electric field. Driven in a radial direction as a whole.

The T-V characteristic thereof is characterized by the sum of the rubbing direction effects in the conventional stripe-patterned transverse electric field electrode as shown in FIG. 4B.

Hereinafter, a specific embodiment of a circular electrode structure FFS mode liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

First Embodiment

5 is a plan view of a substrate for an FFS mode liquid crystal display device according to a first embodiment of the present invention.

As shown, the gate wiring 112 is formed in the first direction, the data wiring 128 is formed in the second direction crossing the first direction, and corresponds to the gate wiring 112 in the first direction. The common wiring 142 is formed, and the intersection region of the gate wiring 112 and the data wiring 128 is defined as the pixel region P. FIG.

In the common wiring 142, a common electrode 144 having a flat shape corresponding to the pixel region P is formed for each pixel region P. As illustrated in FIG.

The thin film transistor T is formed at the intersection of the gate line 112 and the data line 128, and the lead line 140 is formed by being connected to the thin film transistor T and the lead line 140. ), The connection line 141 is extended, and in the connection line 141, the pixel electrode 138 having a plurality of circular patterns is branched.

The pixel electrode 138 has a plurality of patterns having the same center portion and arranged outwardly from the inside, and has a structure in which the first to third pixel electrode patterns 138a, 138b, and 138c are sequentially arranged from the center portion to the outside. To achieve.

In the FFS mode according to the present embodiment, since the pixel electrode 138 pattern spaced apart region and the overlapping region between the pixel electrode 138 and the common electrode 144 are used as the opening region, the pixel electrode 138 and the common electrode ( 144 is selected from a transparent conductive material, for example, indium tin oxide (ITO).

In the case of the FFS mode according to the present invention, the storage capacitor Cst is formed in a state where an overlapping region between the common electrode 144 and the pixel electrode 138 is provided, even though a storage capacitor is not separately configured. It is characterized by.

In the drawing, the hatched region is a black matrix forming region BA. The black matrix, which is not shown, is positioned on the opposite substrate or the same substrate, and serves to block light in the region where the liquid crystal is not driven. The black matrix forming area BA includes an open part 146 that exposes a main area of the pixel area, and is formed in an area including a non-pixel area and an edge of the common electrode 144. It may have a larger size than the electrode pattern 138c and may have a circular structure.

6A through 6F are diagrams illustrating, in stages, a manufacturing process of a substrate for an FFS mode liquid crystal display by a six mask process according to a first embodiment of the present invention.

The mask process described above refers to a process of patterning by photolithography using a photosensitive material.

FIG. 6A illustrates a step of forming a gate wiring 112 on the substrate 110 and having a gate electrode 116 in the first direction by a first mask process.

6B illustrates forming a gate insulating film (not shown) in an area covering the gate wiring 112 and forming a semiconductor layer 122 in an area covering the gate electrode 116 by a second mask process. 6C illustrates a data line 128, a source electrode 130 branching from the data line 128, and the source electrode 130 in a second direction crossing the first direction by a third mask process. ) To form a drain electrode 132 having an island pattern structure spaced apart from each other.

An area where the gate line 112 and the data line 128 intersect is defined as a pixel area P. FIG.

The source electrode 130 and the drain electrode 132 are positioned to overlap both sides of the semiconductor layer 122.

Through this step, the gate electrode 116, the semiconductor layer 122, the source electrode 130, and the drain electrode 132 form a thin film transistor (T).

Exposing the intrinsic semiconductor material of the semiconductor layer 122 positioned in the spaced interval between the source electrode 130 and the drain electrode 132 to form an exposed intrinsic semiconductor material region as a channel (ch).

Subsequently, FIG. 6D illustrates forming a protective layer (not shown) including the thin film transistor T on the entire surface of the substrate, and forming the gate wiring 112 in the first direction by a fourth mask process on the protective layer. ) And the common electrode 136 spaced apart from the common wiring 134 and the common electrode 136 branched in a flat pattern corresponding to the pixel region P in the pixel region P unit of the common wiring 134. Forming.

6E illustrates forming an insulating layer (not shown) on the entire surface of the substrate covering the common wiring 134 and the common electrode 136, and forming the drain electrode (not shown) on the insulating layer and the protective layer by a fifth mask process. A drain contact hole 138 exposing part 132 is formed.

FIG. 6F illustrates a lead wire 140 connected to the drain electrode 132 through the drain contact hole 138 by a sixth mask process on the insulating layer including the drain contact hole 138, and the lead wires 140. The forming of the connection line 142 extending in the second direction in the wiring 140 and the pixel electrode 144 branching from the connection wiring 142 is performed.

The pixel electrode 144 is formed of a plurality of patterns having a circular structure which are sequentially formed to be spaced apart from inside to outside at the same center.

In more detail, the first pixel electrode pattern 144a having a circular pattern in the center, the second pixel electrode pattern 144b having a circular band structure around the first pixel electrode pattern 144a, A third pixel electrode pattern 144c having a circular band structure is formed at an outer circumference of the two pixel electrode patterns 144b.

It is important that the common electrode 136 and the pixel electrode 144 are located in an overlapping area with each other.

Hereinafter, a process of manufacturing the FFS mode liquid crystal display device by the low mask process in which the number of masks is reduced compared to the manufacturing process according to the first embodiment will be described.

Second Embodiment

7A to 7E are plan views illustrating, in stages, a manufacturing process of an FFS mode liquid crystal display using a five mask according to a second embodiment of the present invention. The process description overlapping with the five mask process according to the first embodiment will be briefly described. do.

FIG. 7A is a step of forming the gate wiring 212 and the gate electrode 216 on the substrate 210 in the same manner as in FIG. 6A by the first mask process.

FIG. 7B illustrates forming a gate insulating film (not shown) in an area covering the gate wiring 212 and the gate electrode 216, stacking a semiconductor material and a metal material on the gate insulating film in order, and then diffraction exposure A data wiring 228, a source electrode 230, and a drain electrode 232 are formed using the metal material by a second mask process including a method, and the data wiring 228, the source electrode 230, The semiconductor material is formed as the semiconductor material layer 225 in a pattern structure corresponding to the drain electrode 232. The semiconductor material layer 225 includes a spaced interval between the source electrode 230 and the drain electrode 232, and the semiconductor material layer 225 at a position corresponding to the source electrode 230 and the drain electrode 232. ) Forms a semiconductor area (SC).

The gate electrode 216, the semiconductor region SC of the semiconductor material layer 225, the source electrode 230, and the drain electrode 232 form a thin film transistor T.

In this step, a channel ch is formed by exposing a pure semiconductor region of the semiconductor material layer 225 positioned in a spaced interval between the source electrode 230 and the drain electrode 232 by diffraction exposure method. .

For example, when using a positive type photosensitive material from which an exposed portion is removed, a mask having a slit portion is disposed at a position corresponding to the channel portion to form a photosensitive material layer having a thickness thinner than a portion to form a pattern in the channel portion. As a method of forming, the semiconductor process and the source / drain process may be simultaneously performed in one mask process.

7C illustrates forming a protective layer (not shown) on the entire surface of the substrate covering the thin film transistor T, and forming a common wiring 234 and a common electrode 236 on the protective layer by a third mask process. Forming.

The material forming the common wiring 234 and the common electrode 236 is selected from a transparent conductive material, and for example, may be made of ITO.

Subsequently, FIG. 7D illustrates forming an insulating layer (not shown) in an area covering the common wiring 234 and the common electrode 236, and forming the drain electrode on the insulating layer and the protective layer by a fourth mask process. A drain contact hole 238 exposing a portion 232 is partially formed.

FIG. 7E illustrates a lead wire 240 connected to the drain electrode 232 through the drain contact hole 238 by a fifth mask process on an insulating layer including the drain contact hole 238; A connection line 242 extending from the lead wire 240 and a pixel electrode 244 having a circular structure branched from the connection wire 242 are formed.

The pixel electrode 244 is formed of a plurality of patterns, and the specific pattern structure may apply the structure mentioned in 6e.

That is, the pixel electrode 244 is composed of first to third pixel electrode patterns 244a, 244b, and 244c.

Like the common electrode 236, the pixel electrode 244 is selected from a transparent conductive material, and may be, for example, ITO.

Hereinafter, another embodiment of the present invention provides a cochlear electrode structure as another pattern structure of the circular electrode structure.

Looking at the dictionary definition for "snail" described above, for example, from "Q" on the string "OQ" or its extension with the end point "O" on the circle "a" in diameter When the line segment "QP" of length "b" is taken on both sides of "Q", "Q" means the curve which is the trace of "P" when it moves over this circumference, and is a cochlear shape or Also called Lima Song.

Third Embodiment

FIG. 8 is a plan view of a substrate for an FFS mode liquid crystal display according to a third embodiment of the present invention. The snail-shaped electrode structure is illustrated, and portions except for the first embodiment and the circular electrode structure are the same. As such, descriptions of overlapping portions will be omitted.

As illustrated, a flat common electrode 344 is formed in the pixel region P by being connected to the common wiring 342, and a drawing wiring 340 is formed by being connected to the thin film transistor T. In the region extending from the lead wire 340 and overlapping the common electrode 344, a pixel electrode 338 having a snail-shaped structure is formed.

In the case of the first embodiment, when the pixel electrode is formed by a combination of a plurality of circular band structures formed of closed curves, in this embodiment, one pixel electrode maintains a predetermined distance from the outside to the inside or the inside to the outside without a separate connection line. And characterized in that formed into a snail.

In this structure as well, the liquid crystal is driven by a transverse electric field in the spaced area between the snail-shaped patterns of the pixel electrode 338 and the region in which the pixel electrode 338 and the common electrode 344 overlap. Due to structural features, the pixel electrode 338 and the common electrode 344 are selected from a transparent conductive material, and may be, for example, ITO.

An overlapping region between the common electrode 344 and the pixel electrode 338 forms a storage capacitor Cst in a state where an insulator (not shown) is interposed therebetween.

In the drawing, the hatched region corresponds to a black matrix area (BA) having a circular open portion 346 exposing the pixel electrode 338.

9A to 9C are plan views illustrating, in steps, a process of manufacturing a substrate for a coarse structure FFS mode transverse field type liquid crystal display device by a six mask process according to a third embodiment of the present invention. Since it can be applied in the same manner as in the first embodiment, it is shown in one drawing.

9A shows the steps of forming the gate wiring 312 and the gate electrode 316 by the first mask process, forming the semiconductor layer 322 by the second mask process, and by the third mask process. The data line 338, the source electrode 330, and the drain electrode 332 are formed, and the thin film transistor includes the gate electrode 316, the semiconductor layer 322, the source electrode 330, and the drain electrode 332. And forming a channel (ch) made of an intrinsic semiconductor material region using the source electrode 330 and the drain electrode 332 as a mask.

Next, forming a protective layer (not shown) on the entire surface of the substrate including the thin film transistor, and by a fourth mask process on the protective layer, and positioned in a direction parallel to the gate wiring 312, the A common wiring 334 having a flat common electrode 336 corresponding to the pixel region P is formed.

9B illustrates forming an insulating layer (not shown) on the entire surface of the substrate including the common electrode 336 and the common wiring 334, and forming the drain electrode (not shown) on the insulating layer and the protective layer by a fifth mask process. A drain contact hole 338 exposing part 332 is partially formed.

FIG. 9C illustrates a lead wire 340 connected to the drain electrode 332 through the drain contact hole 338 by a sixth mask process on an insulating layer including the drain contact hole 338. A pixel electrode 344 having a cochlear structure extending from the lead wire 340 is formed.

Hereinafter, a process of manufacturing the substrate for the FFS mode liquid crystal display device using the cochlear electrode structure by the process in which the number of mask processes is reduced compared to the manufacturing process according to the third embodiment will be described.

Fourth Embodiment

10A to 10C are plan views illustrating, in steps, a process of manufacturing a substrate for an FFS mode liquid crystal display device by a five mask process according to a fourth embodiment of the present invention.

10A shows forming the gate wiring 412 and the gate electrode 416 by the first mask process, and the data wiring 428, the source electrode 430, and the drain electrode 432 by the second mask process. And a pattern structure corresponding to the data line 428, the source electrode 430, and the drain electrode 432, and the semiconductor region SC at a position corresponding to the source electrode 430 and the drain electrode 432. Forming a semiconductor material layer 425 having a.

The method may further include forming a channel ch by a diffraction exposure method in the same mask process, wherein the gate electrode 416, the semiconductor region SC of the semiconductor material layer 425, the source electrode 430, and the drain are formed. The electrode 432 forms a thin film transistor (T), and forming a protective layer (not shown) on the entire surface of the substrate covering the thin film transistor (T), and by a third mask process on the protective layer, the gate A common wiring 434 is formed in a direction parallel to the wiring 412 and has a flat common electrode 436 corresponding to the pixel region P. Referring to FIG.

10B illustrates forming an insulating layer (not shown) on the entire surface of the substrate including the common electrode 436 and the common wiring 434, and forming the drain electrode on the insulating layer and the protective layer by a fourth mask process. A drain contact hole 438 exposing part 432 is formed.

FIG. 10C illustrates the lead wire 440 connected to the drain electrode 432 through the drain contact hole 438 by a fifth mask process on the insulating layer including the drain contact hole 438. A pixel electrode 444 having a cochlear structure extending from the lead wire 440 is formed.

11A and 11B are diagrams for explaining the degree of reduction of the aperture ratio at the time of the bonding misalignment according to the pattern structure of the transverse electric field electrode, FIG. 11A is a conventional stripe pattern type transverse electric field electrode, and FIG. 11B is a circular pattern according to the present invention. It is a figure about a type transverse electric field electrode.

As shown, a misalignment occurs in a process of bonding the substrates 450 and 470 on which the in-plane electrodes IE1 and IE2 are formed and the substrates 460 and 480 on which the black matrix BM is formed. In this case, the black matrices BM1 and BM2 may deviate from the design value and may have a large overlapping area with the transverse field electrodes IE1 and IE2, and such misalignment may cause a reduction in the opening area.

In the case of FIG. 11A, the overlap region XIa between the black matrix BM1 and the transverse electric field IE1 overlaps in the longitudinal direction of the transverse electric field IE1 due to the pattern structure of the transverse electric field electrode IE1. In the case of FIG. 11B, as the transverse electric field IE2 according to the present invention has a circular electrode structure, the overlap region XIb between the black matrix BM2 and the transverse electric field IE2 is significantly reduced compared to FIG. 11A. Can be.

Therefore, according to the circular electrode structure according to the present invention, the bonding process margin is increased, it is possible to reduce the luminance difference for each product.

Hereinafter, another embodiment of the present invention will be described with respect to the storage capacitor enhancement structure.

Fifth Embodiment

FIG. 12 is a plan view of an FFS mode liquid crystal display device according to a fifth embodiment of the present invention, and will be described with reference to features distinguishing from the first embodiment.

As illustrated, in the third pixel electrode pattern 538c, which is the outermost pattern of the pixel electrode 538, the capacitor electrode 540 extends to overlap the front gate line 512.

That is, the first storage capacitor Cst1 in the overlapping region between the pixel electrode 538 and the common electrode 520, and the second storage capacitor Cst2 in the overlapping region between the capacitor electrode 540 and the gate wiring 512. As the storage capacitor Cst is configured as the sum, the liquid crystal can be stably driven by the increase of the storage capacitor Cst rather than the structures according to the first and third embodiments.

Hereinafter, in another embodiment of the present invention, a red, green, blue, and white subpixel having a square structure constitutes a four-color pixel structure for improving aperture ratio. The present invention proposes a circular electrode structure FFS mode liquid crystal display device.

Sixth Embodiment

FIG. 13 is a plan view of an FFS mode liquid crystal display according to a sixth exemplary embodiment of the present invention, and has a square red / green / blue / white 4-color pixel structure. FIG.

In the general red, green, and blue three-color pixel structure, as the subpixel is composed of a rectangular structure, the short axis width in the pixel area determines the diameter of the circular electrode, and the dummy area occupies a large specific gravity in addition to the circular electrode. There was a limit to improvement.

However, in the square pixel structure, since the pixel area has the same distance from the center to the four sides, there is no obstacle in determining the diameter of the circular electrode, and as the specific gravity of the dummy region other than the circular electrode is significantly reduced, the aperture ratio can be effectively improved. have.

As shown in the drawing, four red, green, blue, and white subpixels (SP (red), SP (green), SP (blue), and SP (white)) constitute one pixel PX. When the circular electrode structure FFS mode liquid crystal display device is applied to the color pixel structure, the aperture ratio can be effectively increased by increasing the utilization efficiency of the pixel area.

Hereinafter, an embodiment in which the pixel electrode is formed in a flat shape and the common electrode has a circular electrode structure will be described.

Seventh Embodiment

14A and 14B are plan views of a FFS mode liquid crystal display according to a seventh embodiment of the present invention. FIG. 14A is a FFS mode liquid crystal display including a circular band structure and FIG. 14B is a coarse structure common electrode. It will be described focusing on the characteristic parts that are distinguished from the first embodiment.

In the present embodiment, the pixel electrodes 738 and 838 are formed in a flat shape at positions corresponding to the pixel regions P, and the common electrodes 744 and 844 are circular at positions overlapping the pixel electrodes 738 and 838. Characterized in that the structure.

Also in this structure, the region in which the pixel electrodes 738 and 838 and the common electrode 744 and 844 overlap each other forms a storage capacitor Cst with an insulator (not shown) interposed therebetween, and is common with the pixel electrodes 738 and 838. The materials constituting the electrodes 744 and 844 may be selected from a transparent conductive material, and may be formed of, for example, ITO. The spaced intervals between the common electrodes 744 and 844 and the overlapping regions of the two electrodes form an opening region. As in the first embodiment, as the opening region has a circular structure, the viewing angle characteristic may be improved.

The common electrode 744 according to FIG. 14A has a circular band structure, and the common electrode 844 according to FIG. 14B has a cochlear structure.

In more detail, the common electrode 744 according to FIG. 14A includes a first common electrode pattern 744a positioned in an area having a circular open portion 746 and surrounding an edge of the pixel region P, and The first common electrode pattern 744a includes a second common electrode pattern 744b positioned in a circular band structure. The pixel electrode 738 has a larger size than the open part 746 in the first common electrode pattern 744a.

The common electrode 844 according to FIG. 14B has a cochlear open portion 846 and is positioned in an area surrounding the edge of the pixel region P, and the pixel electrode 838 is formed in the common electrode 844. 846) and larger size.

In addition, the structure and manufacturing process according to the first to sixth embodiments can be applied, including the characteristic structure according to the present embodiment.

However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, the circular electrode structure according to the present invention corresponds to a structure including an elliptical electrode structure.

As described above, according to the FFS mode liquid crystal display device and the manufacturing method thereof, the first electrode having a flat shape in which the electrode forming the transverse electric field is formed to correspond to the pixel region, and the circular shape at the position overlapping the first electrode. Since the opening region between the first and second electrodes has a circular structure, the liquid crystal directors are the same in all directions, thereby improving the viewing angle, and the aperture ratio is reduced by applying a square pixel structure. It can be improved, and the overlapping area with the black matrix is reduced, which can have the advantage of minimizing the luminance difference that may occur in each product during the adhesion misalignment.

1 is a view for explaining a driving principle of a general transverse electric field type liquid crystal display device.

2 is a schematic plan view of an array substrate for a general transverse electric field type liquid crystal display device.

3A and 3B are views of a general FFS mode liquid crystal display, where FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view showing a cross section taken along the cutting line " IIIb-IIIb "

4A and 4B are diagrams illustrating a pattern structure of an FFS mode circular electrode according to the present invention, FIG. 4A is a driving characteristic of liquid crystal molecules for each domain, and FIG. 4B is a graph of a T-V curve graph.

5 is a plan view of a substrate for an FFS mode liquid crystal display device according to a first embodiment of the present invention;

6A through 6F are steps illustrating a manufacturing process of a substrate for an FFS mode liquid crystal display device by a six mask process according to a first embodiment of the present invention.

7A to 7E are plan views illustrating step-by-step manufacturing processes of an FFS mode liquid crystal display device using five masks according to a second embodiment of the present invention.

8 is a plan view of a substrate for an FFS mode liquid crystal display device according to a third embodiment of the present invention;

9A to 9C are plan views illustrating a step-by-step process of manufacturing a substrate for a cosmic structure FFS mode transverse field type liquid crystal display device by a six mask process according to a third embodiment of the present invention.

10A to 10C are plan views illustrating a step of manufacturing a substrate for an FFS mode liquid crystal display by a five mask process according to a fourth embodiment of the present invention.

11A and 11B are diagrams for explaining the degree of reduction of the aperture ratio at the time of the bonding misalignment according to the pattern structure of the transverse electric field electrode, FIG. 11A is a conventional stripe pattern type transverse electric field electrode, and FIG. 11B is a circular pattern according to the present invention. Drawing for type transverse field electrode.

12 is a plan view of an FFS mode liquid crystal display device according to a fifth embodiment of the present invention;

FIG. 13 is a plan view of an FFS mode liquid crystal display device according to a sixth embodiment of the present invention; FIG.

14A and 14B are plan views of an FFS mode liquid crystal display device according to a seventh embodiment of the present invention;

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

112: gate wiring 128: data wiring

138a, 138b, and 138c: first to third pixel electrode patterns

138: pixel electrode 140: lead-out wiring

141: connection wiring 142: common wiring

144: common electrode 146: open portion

BA: Black matrix forming region Cst: Storage capacitor

P: pixel area T: thin film transistor

Claims (21)

A gate wiring formed on the first substrate in a first direction; A data line formed in a second direction crossing the first direction; A common wiring formed to be spaced apart from the gate wiring in the first direction; A common electrode defined by the pixel area, the intersection area of the gate line and the data line, branched from the common line and formed in a flat shape corresponding to the pixel area; A thin film transistor formed at an intersection point of the gate line and the data line; A lead wire connected to the thin film transistor; A pixel electrode branched from the lead wire and formed in a circular structure in an area overlapping the common electrode with an insulator interposed therebetween; A second substrate disposed to face the first substrate; Liquid crystal layer interposed between the first and second substrates The common electrode and the pixel electrode are made of a transparent conductive material, and the pixel electrode is formed of at least two or more patterns, and includes a spaced interval between the pixel electrode patterns and an overlapping region between the common electrode and the pixel electrode. A FFS (Fringe Field Switching Mode) mode liquid crystal display device characterized by driving liquid crystal molecules of the liquid crystal layer by a transverse electric field in a region. A gate wiring formed on the first substrate in a first direction; A data line formed in a second direction crossing the first direction; A common wiring formed to be spaced apart from the gate wiring in the first direction; A common electrode defined by the pixel area, wherein the intersection area between the gate line and the data line is defined as a pixel area, and has a circular structure branched from the common wire to correspond to the pixel area; A thin film transistor formed at an intersection point of the gate line and the data line; A pixel electrode connected to the thin film transistor and formed in a flat shape in an area overlapping the common electrode with an insulator interposed therebetween; A second substrate disposed to face the first substrate; Liquid crystal layer interposed between the first and second substrates The common electrode and the pixel electrode are made of a transparent conductive material, and the common electrode is formed of at least two or more patterns, and includes a spaced interval between the common electrode patterns and an overlapping region between the common electrode and the pixel electrode. A FFS (Fringe Field Switching Mode) mode liquid crystal display device characterized by driving liquid crystal molecules of the liquid crystal layer by a transverse electric field in a region. The method of claim 1, And the pixel electrode is formed of a plurality of patterns having the same central portion and arranged inwardly outward. The method of claim 3, wherein The pixel electrode has a structure in which the first to third pixel electrode patterns are arranged in order from the center outward. The method of claim 2, The common electrode may include a first common electrode pattern positioned in an area surrounding an edge of the pixel region and having a circular open portion, and a second common electrode pattern having a circular band structure inside the first common electrode pattern. FFS mode liquid crystal display. The method according to claim 1 or 2, The overlapping region between the common electrode and the pixel electrode forms a storage capacitor with an insulator (not shown) interposed therebetween. The method according to claim 1 or 2, An open area for exposing a main area of the pixel area, wherein the area covering the non-pixel area and the edge of the common electrode is an area covered by a black matrix. The method of claim 7, wherein And the open portion has a circular structure. The method of claim 1, And the pixel electrode has a coarse structure. The method of claim 2, And the common electrode has a coarse structure. The method of claim 10, The common electrode has the cochlear open part and is positioned in an area surrounding an edge of the pixel area. The method according to claim 1 or 2, And the pixel area has a square structure. The method of claim 12, And a four-color pixel structure in which one subpixel comprises one subpixel and four red, green, blue, and white subpixels constitute one pixel. The method according to claim 1 or 2, And a capacitor electrode positioned to overlap the front gate line and a predetermined region in the pixel electrode, and an overlap region between the capacitor electrode and the gate line forms another storage capacitor. The method according to claim 1 or 2, The thin film transistor includes an FFS including a gate electrode branched from the gate line, a semiconductor layer positioned to overlap the gate electrode, a source electrode branched from the data line, and a drain electrode spaced apart from the source electrode. Method of manufacturing a mode liquid crystal display device. The method of claim 1, And the pixel electrode is connected to the thin film transistor through a lead wire. Forming a gate wiring on the substrate in a first direction; Forming a data line in a second direction crossing the first direction, and forming a thin film transistor at an intersection point of the gate line and the data line; Forming a first FFS (Fringe Field Switching) electrode having a flat pattern on the thin film transistor with an insulator interposed therebetween; Forming a second FFS electrode having a circular structure and overlapping with the first FFS electrode and another insulator; The method of claim 1, wherein the first and second FFS electrodes are made of a transparent conductive material. The method of claim 17, The first FFS electrode is a common electrode, and the forming of the common electrode may further include forming a common wiring connected to the common electrode and spaced apart from the gate wiring in the first direction. A manufacturing method of an FFS mode liquid crystal display device. The method of claim 17, And the second FFS electrode is a pixel electrode, and the pixel electrode is connected to the thin film transistor. The method of claim 19, The forming of the pixel electrode may include sequentially forming a plurality of pixel electrode patterns having the same center portion and having a circular band structure inwardly and maintaining a predetermined interval therebetween. The method of claim 19, The thin film transistor includes a gate electrode, a source electrode, and a drain electrode, the two insulators have a drain contact hole partially exposing the drain electrode, and the pixel electrode is a drain electrode of the thin film transistor through the drain contact hole. Method of manufacturing a FFS mode liquid crystal display device characterized in that connected to.