KR20080051569A - In-plane switching mode liquid crystal display device and the method for fabricating thereof - Google Patents

Abstract

An in-plane switching mode liquid crystal display device and a method for fabricating thereof are provided to form the liquid crystal display device having high quality without reducing opening ratio. An in-plane switching mode liquid crystal display device includes a first substrate, a thin transistor(T), a common electrode(360) and a pixel electrode(370), a first orientation film, a second substrate, a black matrix(312), a color filter of red, green and blue, a column spacer, a second orientation film, and a negative liquid crystal layer. The first substrate divides a pixel area and a non-pixel area. The thin transistor is formed between a gate line and a data line. The second substrate is located with interval from the first substrate. The black matrix is formed corresponding to the non-pixel area of the second substrate. The negative liquid crystal layer is located between the first substrate and the second substrate.

Description

In-plane switching mode liquid crystal display device and the method for fabricating

1 is a plan view showing an array substrate for a general transverse electric field type liquid crystal display device.

2A and 2B are diagrams showing electrical characteristics of liquid crystals.

3 is a plan view showing a general transverse electric field type liquid crystal display device.

4 is a cross-sectional view taken along the line IV-IV of FIG. 3.

5 is a plan view illustrating unit pixels of an array substrate for a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention.

6A to 6D are cross-sectional views taken along the line VI-VI of FIG. 5.

7A and 7B illustrate electrical characteristics of liquid crystals.

8 is a plan view showing a transverse electric field type liquid crystal display device according to the present invention.

9 is a cross-sectional view taken along the line VII-VII of FIG. 8.

* Explanation of symbols for the main parts of the drawings *

300: array substrate 310: color filter substrate

312: black matrix 320: gate wiring

325: gate electrode 326: color filter

330 data wiring 331 data connection wiring

332: source electrode 334: drain electrode

340 active layer 350 common wiring

360: pixel electrode 370: common electrode

395: column spacer CH4: drain contact hole

CH5: common contact hole ←: rubbing direction

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to manufacturing a liquid crystal display device which realizes high quality by preventing light leakage caused by column spacers pushed on a rubbing cloth during a rubbing process of an alignment layer.

In particular, the present invention relates to a transverse electric field type liquid crystal display device in which the first and second electrodes for driving the liquid crystal of the liquid crystal display device are formed on the same plane.

In general, the driving principle of the liquid crystal display device uses the optical anisotropy and polarization of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the liquid crystal may be artificially applied to control the direction of the molecular arrangement.

Accordingly, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal due to optical anisotropy to express image information.

Hereinafter, a general transverse electric field type liquid crystal display device will be described with reference to the accompanying drawings.

1 is a plan view illustrating an array substrate for a general transverse electric field type liquid crystal display device, which will be described with reference to the drawings.

As shown, the gate wiring 20 is formed in one direction on the transparent substrate 10, and a part of the gate wiring 20 is used as the gate electrode 25.

The data line 30 defining the pixel region P by crossing the gate line 20 perpendicular to the gate line 20 is in contact with the source electrode 32 having a U shape through the data connection line 31. In this case, the source electrode 32 is configured to overlap a part of the gate electrode 25, and the drain electrode 34 is formed in an I-shape to be spaced apart from the source electrode 32.

An active layer 40 made of pure amorphous silicon and an ohmic contact layer (not shown) made of an impurity amorphous silicon layer are stacked between the gate electrode 25 and the source and drain electrodes 32 and 34. The ohmic contact layer exposed between the drain electrodes 32 and 34 is removed to expose the active layer 40.

The pixel electrode 60, which is in contact with the drain electrode 34 through the drain contact hole CH1 exposing a part of the drain electrode 34, is configured in the pixel region P.

In this case, the pixel electrode 60 includes an extension part 60a connected to the drain electrode 34 and a plurality of vertical parts 60b vertically branched to the pixel area P from the extension part 60a. do.

The common wiring 50 is spaced apart from the gate wiring 20 in parallel, and the common electrodes 70 branched from the common wiring 50 are parallel to the pixel electrode vertical part 60b. It is composed of staggered.

The array substrate having such a configuration is bonded to the color filter substrate, and the liquid crystal is injected through the liquid crystal injection hole formed between the two substrates, and sealed with a thermosetting resin.

Here, the liquid crystal described above may be classified into positive liquid crystals having positive dielectric anisotropy and negative liquid crystals having negative dielectric anisotropy according to the electrical characteristic classification, and liquid crystal molecules having positive dielectric anisotropy are applied with an electric field. The long axis of the liquid crystal molecules is arranged in parallel in the direction of the direction, and the liquid crystal molecules having negative dielectric anisotropy are arranged in the direction in which the long axis of the liquid crystal molecules is perpendicular to the direction in which the electric field is applied.

Hereinafter, the electrical characteristics of the liquid crystal described above will be described in detail with reference to the accompanying drawings.

2A and 2B illustrate electrical characteristics of liquid crystals. For the convenience of description, the array substrate including the pixel electrode and the common electrode will be mainly shown.

As shown in FIG. 2A, the rubbing direction of an alignment film (not shown) advances to the y-axis direction, and the case where positive liquid crystal is applied is shown.

In this case, when a voltage is applied, a horizontal electric field is generated between the common electrode 70 and the pixel electrode vertical part 60b to move the liquid crystal molecules 80 in the counterclockwise direction due to the aforementioned electrical characteristics.

In contrast, as shown in FIG. 2B, when the rubbing direction of the alignment layer is moved in the y-axis direction and a negative liquid crystal is applied, an electric field is generated between the common electrode 70 and the pixel electrode vertical part 60b. Even so, the movement of the liquid crystal molecules 85 does not occur due to the above-described electrical characteristics.

Therefore, when the negative liquid crystal is applied and the rubbing treatment of the alignment film in the y-axis direction is lost, the function as the liquid crystal display device is lost. Therefore, it is necessary to change to the x-axis direction in which the axial direction is rotated by 90 degrees.

However, in a general liquid crystal display device, rubbing treatment has been performed in the y-axis direction. When rubbing treatment is performed in this direction, the residues of the column spacer pushed by the rubbing cloth move to the pixel region, and thus the residues are not shielded. Light leakage can occur.

Hereinafter, this will be described in detail with reference to the accompanying drawings.

3 is a plan view illustrating a general transverse electric field type liquid crystal display, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, and simultaneously shows an array substrate and a color filter substrate.

3 and 4 are the same as those in FIG. 1 in the configuration, and only important elements will be described.

3 and 4, the color filter substrate, which is the upper substrate 100, and the array substrate, which is the lower substrate 110, face each other, and a negative liquid crystal is formed between the upper and lower substrates 100 and 110. A liquid crystal layer 165 made of a liquid crystal is interposed.

A gate wiring 120 is formed on the transparent substrate 102 of the lower substrate 110, and a gate insulating film and a protective film 145 are formed on the gate wiring 120. The common electrode 170 and the pixel electrode 160 are formed on the gate insulating layer and the passivation layer 145, and a lower alignment layer 175 is formed on the entire upper surface of the gate insulating layer and the passivation layer 145.

A black matrix 112 is formed on the transparent substrate 101 of the upper substrate 100 to block light from being incident to a portion other than the pixel region P, and the upper substrate 100 of the lower substrate 110 is formed on the transparent substrate 101. The color filter 126 is configured to correspond to the pixel region P. FIG.

In addition, an overcoat layer 114 is formed on the entire upper surface of the black matrix 112 and the color filter 126, and the overcoat layer 114 corresponds to the gate wiring 120 of the lower substrate 110. Column spacers 190 are formed in the portion.

In this case, the column spacer 190 is configured for the purpose of maintaining a constant cell gap (cell gap) of both substrates (100, 110), for example, may be made of a polymer resin.

The upper alignment layer 116 having the same function as the lower alignment layer 175 is formed on the entire surface of the upper transparent substrate 102 having the column spacer 190.

Here, the upper and lower alignment layers 116 and 175 are subjected to rubbing in the y-axis direction.

However, when the rubbing treatment is performed in the y-axis direction in the rubbing of the alignment layer 116, rubbing scratches are generated along the y-axis, which is the rubbing progress direction, by the column spacer 190 being pushed by the rubbing cloth. .

At this time, the y axis in the rubbing traveling direction is a portion in which the pixel region P is formed, and when rubbing scratches are generated by the residues of the column spacer 190 pushed onto the rubbing cloth in the pixel region P, Light leakage occurs at P).

In order to solve this problem, when the luminance of the backlight configured on the back of the liquid crystal panel is improved, the black luminance at the light leakage portion is lowered, resulting in a problem that the contrast ratio of the entire panel is lowered.

The present invention has been made to solve the above-described problem, and in the present invention, by replacing the positive liquid crystal with the negative liquid crystal, the rubbing traveling direction can be switched in the x-axis direction, which is the direction in which the gate wiring is located.

As a result, even if rubbing scratches occur due to the column spacer pushed by the rubbing cloth during the rubbing process of the alignment layer, a black matrix constituted on the color filter substrate is formed to block light from being incident on the gate wiring and the thin film transistor formed on the array substrate. Since it is constructed along the x-axis direction with sufficient line width, it can be shielded without reducing the aperture ratio.

Therefore, a high quality liquid crystal display device can be manufactured by preventing light leakage.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a first substrate divided into a pixel area and a non-pixel area, and one side and the other side of the pixel area corresponding to the non-pixel area of the first substrate. A gate interconnection and data interconnection intersected with each other, a thin film transistor configured at an intersection of the two interconnections, a common electrode and a pixel electrode spaced apart in parallel to the pixel region;

A first alignment layer formed on the entire surface of the substrate including the gate wiring, the data wiring, and the thin film transistor, and rubbed in the gate wiring direction, a second substrate spaced apart from the first substrate, and the second substrate; A black matrix configured to correspond to the non-pixel region, and red, green, and blue color filters sequentially configured with the black matrix as a boundary portion;

A column spacer configured to correspond to the gate wiring and the black matrix, a second alignment layer formed on the entire surface of the substrate on which the column spacer is formed, and rubbed in the same direction as the first alignment layer, the first substrate and the second substrate It characterized in that it comprises a negative liquid crystal layer interposed between the spaced apart of.

In this case, the negative liquid crystal is characterized in that the dielectric anisotropy is negative (-). In addition, the column spacer is configured on the first substrate, and common wiring spaced in parallel with the gate wiring is further configured.

The common electrode may include a connection part in contact with the common wiring, a plurality of vertical parts branched vertically from the connection part, and the pixel electrode may be extended in contact with the thin film transistor, and may be vertically branched from the extension part. And a plurality of vertical parts, wherein the common parts and the vertical parts of the pixel electrode are alternately spaced apart from each other in parallel to each other, and are bent at the center of the pixel area.

The common electrode and the pixel electrode are made of one selected from indium tin oxide (ITO) and indium zinc oxide (IZO), which are transparent conductive metals.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, the method including preparing a first substrate divided into a pixel region and a non-pixel region, and forming a pixel region corresponding to the non-pixel region of the first substrate. Forming a thin film transistor at a crossing point of the two lines and a gate line and a data line crossing one side and the other side, and forming a common electrode and a pixel electrode spaced in parallel in the pixel area;

Forming a first alignment layer on the front surface of the substrate on which the common electrode and the pixel electrode are formed, which are rubbed in a direction parallel to the gate wiring, and preparing a second substrate facing and spaced apart from the first substrate; Forming a black matrix corresponding to the non-pixel region of the second substrate;

Sequentially forming red, green, and blue color filters using the black matrix as a boundary; forming an overcoat layer on the black matrix and on the red, green, and blue color filters; Forming a column spacer on a portion corresponding to the gate wiring;

Forming a second alignment layer, which is rubbed in the same direction as the first alignment layer, on the entire surface of the substrate on which the column spacers are formed, bonding the first substrate and the second substrate together, Injecting a negative liquid crystal between the two substrates.

In this case, the negative liquid crystal is characterized in that the dielectric anisotropy is negative (-).

Hereinafter, a transverse electric field type liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.

FIG. 5 is a plan view illustrating unit pixels of an array substrate for a transverse electric field type liquid crystal display according to an exemplary embodiment of the present invention, and FIGS. 6A to 6D are cross-sectional views taken along line VI-VI of FIG. do.

As shown in FIGS. 5 and 6A, a gate metal layer (not shown) is formed on the substrate 210 with one selected from a group of conductive metals, and is patterned to be spaced apart from and parallel to the gate wiring 220 in one direction. The common wiring 250 is formed.

In this case, a part of the gate wiring 220 is used as the gate electrode 225.

Next, the gate insulating layer 245 is formed of one selected from the group of inorganic insulating materials such as silicon nitride (SiNx) or silicon oxide (SiO ₂ ) on the entire surface of the substrate 210 on which the gate wiring and the electrodes 220 and 225 are formed. do.

In addition, an active layer 240 made of pure amorphous silicon and an ohmic contact layer 241 made of impurity amorphous silicon are stacked on the gate insulating layer 245.

In this case, the active and ohmic contact layers 240 and 241 are formed in an island shape at a position overlapping with the gate electrode 225.

As shown in FIGS. 5 and 6B, a source and a drain metal layer (not shown) are formed on the substrate 210 on which the active and ohmic contact layers 240 and 241 are formed, one selected from a group of conductive metals, and patterned. The data line 230 is formed to cross the gate line 220 to define the pixel area P, and the gate electrode (eg, the data line 230) extends from the data line 230. A source electrode 232 overlapping with a portion of 220 and a drain electrode 234 spaced apart from the source electrode 232 are formed.

In addition, the active layer 240 is exposed by removing the ohmic contact layer 241 exposed between the source and drain electrodes 232 and 234.

As shown in FIGS. 5 and 6C, an inorganic material, such as silicon nitride (SiNx) or silicon oxide (SiO ₂ ), may be formed on the entire upper surface of the substrate 210 on which the source and drain electrodes 232 and 234 and the data line 230 are formed. The passivation layer 275 is formed of one selected from the group of insulating materials or one selected from the group of organic insulating materials including benzocyclobutene (BCB) and an acrylic resin.

As shown in FIGS. 5 and 6D, the passivation layer 275 corresponding to a part of the drain electrode 234 is removed to form the drain contact hole CH2.

Next, a selected one of a transparent conductive metal group including indium tin oxide (ITO) and indium zinc oxide (IZO) is deposited on the passivation layer 275 on which the drain contact hole CH2 is formed. The pixel electrode 260 and the common electrode 270 are formed in a pattern.

The pixel electrode 260 includes an extension part 260a in contact with the drain electrode 234, and a plurality of vertical parts 260b vertically branched from the extension part 260a to the pixel area P.

Although not shown in detail, the common wire 250 and the common electrode 270 are connected through the common contact hole CH3 exposing a portion of the common wire 250.

The common electrode 270 includes a connecting portion 270a which is in contact with the common wiring 250 and a plurality of vertical portions 270b that are alternately arranged in parallel with the pixel electrode vertical portion 260b at the connecting portion 270a. .

The pixel electrode vertical part 260b and the common electrode vertical part 270b are staggered in parallel with each other and have at least one refraction part. Such a refractive portion is configured for the purpose of improving the viewing angle which is a weak point of the transverse electric field method.

Through the above-described configuration, an array substrate for a transverse electric field type liquid crystal display device according to the present invention can be manufactured.

The array substrate thus manufactured is bonded to the color filter substrate, and the liquid crystal panel is produced through the liquid crystal therebetween.

In this case, in the present invention, a negative liquid crystal is used as the liquid crystal injected between both substrates, and the upper alignment layer of the array substrate and the lower alignment layer of the color filter substrate are rubbed in the x-axis direction.

Hereinafter, the electrical characteristics of the negative liquid crystal initially oriented in the x-axis direction will be described with reference to the accompanying drawings.

7A and 7B illustrate electrical characteristics of a negative liquid crystal. For the convenience of description, an array substrate including a pixel electrode and a common electrode will be mainly shown.

As shown in FIG. 7A, a case in which a negative liquid crystal is applied while the rubbing direction of the alignment layer (not shown) is advanced in the x-axis direction is illustrated.

In this case, when a voltage is applied, an electric field is generated between the common electrode vertical part 270b and the pixel electrode vertical part 260b to move the liquid crystal molecules 285 counterclockwise due to the above-described electrical characteristics.

On the contrary, as shown in FIG. 7B, when the positive liquid crystal is applied while the rubbing direction of the alignment layer (not shown) is advanced in the x-axis direction, the common electrode vertical portion 270b and the pixel electrode are perpendicular to each other. Even if an electric field is generated between the units 260b, the movement of the liquid crystal molecules 280 does not occur due to the above-described electrical characteristics.

Therefore, in the liquid crystal display according to the present invention, the rubbing traveling direction of the alignment layer can be changed in the x-axis direction by replacing the positive liquid crystal with the negative liquid crystal.

Such a change is generated along the gate wiring even if rubbing scratches occur due to the residue of column spacers pushed on the rubbing cloth during the rubbing process of the alignment layer, and thus can be sufficiently shielded by existing blocking means. Do.

In particular, since the x-axis direction is a non-pixel region with respect to the column spacer, there is no fear of foreign matter being transferred to the pixel region P, so that light leakage does not occur in the pixel region P. FIG.

Hereinafter, this will be described in detail with reference to the accompanying drawings.

FIG. 8 is a plan view illustrating a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 9 is a cross-sectional view taken along the line VII-VII of FIG. 8 and simultaneously shows an array substrate and a color filter substrate.

8 and 9 are the same as those in FIG. 5 in the configuration, and thus redundant description will be avoided.

As shown in FIGS. 8 and 9, the color filter substrate, which is the upper substrate 300, and the array substrate, which is the lower substrate 310, face each other, and a negative liquid crystal is formed between the upper and lower substrates 300 and 310. A liquid crystal layer 365 made of a liquid crystal is interposed.

Here, the array substrate 310 and the color filter substrate 300 are bonded to each other in a state produced in a separate process through a separate process, and the liquid crystal layer by injecting the liquid crystal through a liquid crystal injection hole (not shown) formed therebetween Interposed between the 365 and the encapsulating agent to produce a liquid crystal panel.

In detail, the gate wiring 320 is formed on the transparent substrate 302 of the lower substrate 310, and the gate insulating film and the protective film 345 are sequentially formed on the gate wiring 320. The common electrode 360 and the pixel electrode 370 are formed on the gate insulating layer and the passivation layer 345, and a lower alignment layer 375 is formed on the entire upper surface of the gate insulating layer and the protective layer 345 to control the initial alignment of the liquid crystal.

In addition, a black matrix 312 is formed on the transparent substrate 301 of the upper substrate 300 to block light incident to portions other than the pixel region P, and the black matrix 312 is defined as a boundary. Thus, the color filter 326 is formed at the portion corresponding to the pixel region P. FIG.

In addition, an overcoat layer 314 is formed on the black matrix 312, and a column spacer is formed on a portion of the overcoat layer 314 that corresponds to the gate wiring 220 formed on the lower transparent substrate 302. 390 is configured. The column spacer 390 is configured to maintain a constant cell gap of both substrates 300 and 310. For example, the column spacer 390 may be formed of a polyimide-based material.

The upper alignment layer 316 having the same function as the lower alignment layer 375 is formed on the entire surface of the upper transparent substrate 301 having the column spacer 390.

In this case, the upper and lower alignment layers 316 and 375 are rubbed in the x-axis direction.

Here, when the rubbing treatment is performed in the x-axis direction in the forming of the upper and lower alignment layers 316 and 375, even if the rubbing scratch occurs due to the column spacer 290 being pushed by the rubbing cloth, the gate wiring ( Since it occurs along the direction in which the 320 is formed, the pixel region P may be out of an influence zone.

In addition, when the upper and lower substrates 300 and 310 are bonded to each other, the rubbing direction of the upper alignment layer 316 is the same direction as that of the gate wiring 320 and the thin film transistor T of the lower substrate 310. Although rubbing scratches occur in this direction, the 390 can shield them with the black matrix 312.

As a result, light leakage can be prevented without reducing the aperture ratio, and a high quality liquid crystal display device can be manufactured.

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 liquid crystal display according to the present invention may be applied to an array substrate including column spacers.

In the transverse electric field type liquid crystal display device according to the present invention, since the rubbing treatment of the alignment layer can be switched from the y-axis direction to the x-axis direction by applying negative liquid crystal, even if rubbing scratches occur due to the column spacer being pushed by the rubbing cloth, Light leakage does not occur in the pixel area because the same direction as the gate line and the thin film transistor is used instead of the area.

Accordingly, there is an effect that a high quality liquid crystal display device can be manufactured without reducing the aperture ratio by changing the rubbing traveling direction of the alignment layer.

Claims (8)

A first substrate divided into a pixel region and a non-pixel region; A gate wiring and a data wiring intersecting at one side and the other side of the pixel region corresponding to the non-pixel region of the first substrate, and a thin film transistor configured at the intersection of the two wirings; A common electrode and a pixel electrode configured to be spaced apart in parallel to the pixel area; A first alignment layer formed on the entire surface of the substrate on which the gate wiring, the data wiring and the thin film transistor are formed, and which are rubbed in the gate wiring direction; A second substrate spaced apart from and opposed to the first substrate; A black matrix configured to correspond to the non-pixel region of the second substrate; Red, green, and blue color filters sequentially configured with the black matrix as a boundary; A column spacer configured to correspond to the gate wiring and the black matrix; A second alignment layer formed on the entire surface of the substrate including the column spacers and rubbed in the same direction as the first alignment layer; Negative liquid crystal layer interposed between the first substrate and the second substrate spaced apart Liquid crystal display comprising a. The method of claim 1, The negative liquid crystal is a liquid crystal display, characterized in that the dielectric anisotropy is negative (-). The method of claim 1, The column spacer is configured on the first substrate. The method of claim 1, And a common wiring spaced apart in parallel to the gate wiring. The method of claim 4, wherein The common electrode may include a connection part in contact with the common wiring, a plurality of vertical parts branched vertically from the connection part, and the pixel electrode may include an extension part contacting the thin film transistor and a plurality of vertical parts branched from the extension part. And a vertical portion of the common electrode and the vertical portion of the pixel electrode, which are alternately spaced apart from each other in parallel to each other, and bent at a center of the pixel area. The method of claim 1, The common electrode and the pixel electrode are formed of one selected from indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive metal. Preparing a first substrate divided into a pixel region and a non-pixel region; Forming a thin film transistor at a crossing point between the gate line and the data line crossing one side and the other side of the pixel area corresponding to the non-pixel area of the first substrate; Forming a common electrode and a pixel electrode spaced apart from each other in parallel in the pixel area; Forming a first alignment layer on the front surface of the substrate on which the common electrode and the pixel electrode are formed in a rubbing process in a direction parallel to the gate wiring; Preparing a second substrate facing and spaced apart from the first substrate; Forming a black matrix corresponding to the non-pixel region of the second substrate; Sequentially forming red, green, and blue color filters using the black matrix as a boundary; Forming an overcoat layer on the black matrix and on the red, green, and blue color filters; Forming column spacers on the overcoat layer corresponding to the gate lines; Forming a second alignment layer which is rubbed in the same direction as the first alignment layer on the entire surface of the substrate on which the column spacer is formed; Bonding the first substrate and the second substrate to each other; Injecting a negative liquid crystal between the first substrate and the second substrate Liquid crystal display device manufacturing method comprising a. The method of claim 7, wherein The negative liquid crystal (negative liquid crystal) is a liquid crystal display device characterized in that the dielectric anisotropy (-).

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