KR20050017998A - Liquid crystal display - Google Patents

Abstract

PURPOSE: An LCD(Liquid Crystal Display) is provided to improve the aperture ratio of the LCD while preventing light leakage. CONSTITUTION: An LCD includes the first insulating substrate having an inner side and an outer side, a common electrode that is formed on the first insulating substrate and has the first domain splitting members(271,272,273), the second insulating substrate having an inner side and an outer side, and a gate line(121) that is formed on the inner side of the second insulating substrate and includes a gate electrode(124). The inner sides of the first and second substrates face each other. The LCD further includes a storage electrode line(131) that is formed on the inner side of the second insulating substrate and has storage electrodes(133a,133b,133c,133d), a gate insulating layer formed on the gate line and the storage electrode line, and a data line(171) that is formed on the gate insulating layer and has source and drain electrodes(173,175). The LCD also has a passivation layer formed on the data line, a pixel electrode(190) that is formed on the passivation layer and connected to the drain electrode and has the second domain splitting members(191,193), and a liquid crystal layer interposed between the first and second substrates. The storage electrode is partially superposed on the first domain splitting members. The side of the storage electrode, which is adjacent to the first domain splitting member, is arranged in parallel with the first domain splitting member.

Description

Liquid crystal display

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a multi-domain liquid crystal display device which secures a wide viewing angle by dispersing a tilting direction of liquid crystal.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode, a color filter, and the like are formed, and a lower substrate on which a thin film transistor and a pixel electrode are formed. By applying a different potential to form an electric field to change the arrangement of the liquid crystal molecules, and through this to control the light transmittance is a device that represents the image.

However, it is an important disadvantage that the liquid crystal display device has a narrow viewing angle. To overcome these shortcomings, various methods for widening the viewing angle have been developed. Among them, the long axis of the liquid crystal molecules is oriented vertically with respect to the upper and lower substrates in the absence of an electric field, and a constant opening is formed in the pixel electrode and the common electrode opposite thereto. A method of forming a pattern or forming a projection is influential.

As a method of forming the opening pattern, an opening pattern is formed in each of the pixel electrode and the common electrode, and the viewing angle is widened by adjusting the direction in which the liquid crystal molecules lie down using a fringe field formed by the opening patterns. .

The method of forming the protrusions is a method of controlling the lying direction of the liquid crystal molecules by using the electric field distorted by the protrusions by forming the protrusions on the pixel electrode and the common electrode formed on the upper and lower substrates, respectively.

In another method, an opening pattern is formed on the pixel electrode formed on the lower substrate, and a protrusion is formed on the common electrode formed on the upper substrate, so that the liquid crystal lies down using the fringe field formed by the opening pattern and the protrusion. By adjusting the somatic domain.

In such a domain division type liquid crystal display, in order to control the response speed and the texture generated by the sustain electrode, the sustain electrode connection part exists at a position overlapping with an opening pattern or a projection pattern, which is a domain division means of the pixel electrode, and an edge of the pixel electrode. The sustain electrode exists in the.

However, in the liquid crystal display having such a structure, the arrangement of the liquid crystal molecules is disturbed due to the high voltage difference generated between the sustain electrode connection portion and the pixel electrode near the short side of the domain, thereby causing texture. Textures reduce brightness and degrade picture quality.

In addition, the opening ratio decreases due to the area occupied by the sustain electrode. The decrease in the aperture ratio leads to a decrease in luminance.

An object of the present invention is to provide a liquid crystal display device which can improve the aperture ratio while preventing light leakage.

In order to achieve the above object, the present invention provides the following liquid crystal display device. More specifically, a first insulating substrate having an inner surface and an outer surface, a common electrode formed on the first insulating substrate and having a first domain dividing means, It is formed on the inner surface of the second insulating substrate, the second insulating substrate having an inner surface and the outer surface and disposed so as to face the inner surface and the inner surface of the first insulating substrate, and formed on the inner surface of the gate line and the second insulating substrate. A gate electrode formed over the sustain electrode line, the gate line and the sustain electrode line, a data line formed over the gate insulating film, a passivation film formed over the data line, a pixel electrode formed over the passivation film, and having a second domain division means; A liquid crystal layer filled between the first insulating substrate and the second insulating substrate, and before holding The pole is formed so as to partially overlap with the first domain dividing means, and in the overlapping portion, a side adjacent to the first domain dividing means is provided along the first domain dividing means to provide a liquid crystal display device.

In this case, the first domain dividing means and the second domain dividing means are preferably formed by selecting any one of a cutting pattern or a projection pattern.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Next, a structure of a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

1 is a layout view of a liquid crystal display according to a first exemplary embodiment of the present invention, and FIGS. 2A and 2B are lines IIa-IIa 'and IIb-IIb of FIG. 1 of a liquid crystal display according to the first exemplary embodiment of the present invention. Is a cross-sectional view taken along a line.

1 to 2B, the liquid crystal display device is injected between the lower substrate 110 and the upper substrate 210 and the lower substrate 110 and the upper substrate 210 that face the lower substrate 110. And a liquid crystal layer 3 containing liquid crystal molecules oriented perpendicular to the 210.

The lower panel 100 will be described in detail.

A plurality of gate lines 121 and a plurality of storage electrode lines 131 are formed on the insulating substrate 110. The gate line 121 and the storage electrode line 131 mainly extend in the horizontal direction and are separated from each other.

The gate line 121 transmits a gate signal, and a part of each gate line 121 protrudes up and down to form a plurality of gate electrodes 124.

The storage electrode line 131 receives a predetermined voltage such as a common voltage, and the protrusion 137 and the plurality of holding portions having an inclination angle of 45 ° with respect to the storage electrode line 131 protruding to one side and protruding to one side. Electrodes 133a to 133d. The storage electrodes 133a to 133d extend downward and upward in a vertical direction from the storage electrode line 131, and have a length different from those of the first and second vertical portions 133a and 133b and the first vertical portion 133a. Both ends and both ends of the second vertical portion 133b are connected to each other, and have first and second diagonal portions 133c and 133d having an inclination angle of 45 ° with respect to the storage electrode line 131. In addition, the second vertical portion 133b is connected to the protrusion 137 of the storage electrode line 131 at the center portion.

The gate line 121, the storage electrode line 131, and the storage electrodes 133a to 133d may be formed of a silver-based metal such as silver (Ag) or a silver alloy having a low resistivity, and an aluminum-based metal such as aluminum (Al) or an aluminum alloy. In addition to these conductive films, in addition to these conductive films, chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum (Mo) and other materials, which have good physical, chemical and electrical contact properties with ITO or IZO, It may have a multilayer film structure including another conductive film made of an alloy thereof (eg, molybdenum-tungsten (MoW) alloy). An example of the combination of the lower layer and the upper layer is chromium / aluminum-neodymium (Nd) alloy.

Side surfaces of the gate line 121, the storage electrode line 131, and the storage electrodes 133a to 133d are inclined, and the inclination angle is in a range of about 30-80 ° with respect to the surface of the substrate 110.

A gate insulating layer 140 formed of silicon nitride (SiNx) is formed on the gate line 121, the storage electrode line 131, and the storage electrodes 133a to 133d.

A plurality of linear semiconductors 151 made of hydrogenated amorphous silicon (amorphous silicon is abbreviated a-Si) and the like are formed on the gate insulating layer 140. The linear semiconductor 151 extends mainly in the longitudinal direction, from which a plurality of extensions 154 extend toward the gate electrode 124.

A plurality of linear and island ohmic contacts 161 and 165 made of a material such as n + hydrogenated amorphous silicon doped with silicide or n-type impurities at a high concentration are formed on the semiconductor 151. have. The linear contact member 161 has a plurality of protrusions 163, and the protrusions 163 and the island contact members 165 are paired and positioned on the protrusions 154 of the semiconductor 151.

Side surfaces of the semiconductor 151 and the ohmic contacts 161 and 165 are also inclined, and the inclination angle is 30 to 80 degrees.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the ohmic contacts 161 and 165 and the gate insulating layer 140, respectively.

The data line 171 mainly extends in the vertical direction to cross the gate line 121 and transmit a data voltage. A plurality of branches extending from the data line 171 toward the drain electrode 175 forms a source electrode 173. The pair of source electrode 173 and the drain electrode 175 are separated from each other and positioned opposite to the gate electrode 124. The gate electrode 124, the source electrode 173, and the drain electrode 175 form a thin film transistor (TFT) together with the protrusion 154 of the semiconductor 151, and the channel of the thin film transistor is a source. A protrusion 154 is formed between the electrode 173 and the drain electrode 175.

The data line 171 and the drain electrode 175 may also include a conductive film made of a silver metal or an aluminum metal. In addition to the conductive film, chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum (Mo) may be used. ) And other conductive films made of alloys thereof. Sides of the data line 171 and the drain electrode 175 are also inclined, and the inclination angle is in the range of about 30-80 ° with respect to the horizontal plane.

The ohmic contacts 161 and 165 exist only between the semiconductor 151 below and the data line 171 and the drain electrode 175 above and serve to lower the contact resistance. The linear semiconductor 151 has an exposed portion between the source electrode 173 and the drain electrode 175 and is not covered by the data line 171 and the drain electrode 175, and in most places, the linear semiconductor 151 is provided. Is smaller than the width of the data line 171. The semiconductor 151 may increase in width at a portion where the semiconductor 151 meets the gate line 121 to enhance insulation between the gate line 121 and the data line 171.

On the data line 171, the drain electrode 175, and the exposed portion of the semiconductor 151, an organic material having excellent planarization characteristics and photosensitivity, and plasma enhanced chemical vapor deposition (PECVD), is formed. A passivation layer 180 made of a low dielectric constant insulating material such as a-Si: C: O, a-Si: O: F, or silicon nitride, which is an inorganic material, is formed.

The passivation layer 180 is provided with a plurality of contact holes 182 and 185 exposing the end portion 179 and the drain electrode 175 of the data line 171, respectively.

A plurality of pixel electrodes 190 and a plurality of contact assistants 82 are formed on the passivation layer 180 and have domain division means and are connected to the drain electrode 175 through the contact hole 185. It is.

The pixel electrode 190 is formed using a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO), or an opaque conductor having excellent light reflection characteristics such as aluminum (Al). The domain dividing means formed on the pixel electrode 190 is disposed on the horizontal cutout pattern 192 and the upper and lower portions of the half-divided pixel electrode 190 formed in the horizontal direction at the positions half-dividing the pixel electrode 190. The diagonal cutting patterns 191 and 193 are formed in the diagonal direction. At this time, the upper oblique cut pattern 191 is perpendicular to the lower oblique cut pattern 193. This is to evenly distribute the direction of the fringe field in four directions.

The contact auxiliary members 82 are connected to the end portions 179 of the data lines through the contact holes 182, respectively. The contact assisting member 82 is not essential to serve to protect adhesiveness between the end portion 129 of the data line 171 and an external device and to protect them, and application thereof is optional.

The upper panel 200 will be described in detail.

A black matrix (not shown) is formed on the insulating substrate 210 to prevent light leakage. On the black matrix, red (R), green (G), and blue (B) color filters 230 are formed. The common electrode 270 having domain dividing means is formed on the color filter 230. The common electrode 270 is formed of a transparent conductor such as ITO or indium zinc oxide (IZO).

The cutting patterns 271, 272, and 273, which are the domain dividing means of the common electrode 270, sandwich the diagonal cutting patterns 191 and 193 of the pixel electrode 190 in the center thereof, and the parallel patterns of the diagonal electrode and the pixel electrode 190 are parallel to each other. It includes a refraction portion that overlaps the sides. At this time, the refraction portion is classified into a longitudinal refraction portion and a horizontal refraction portion.

Aligning and combining the thin film transistor substrate of the lower display panel 100 and the color filter substrate of the upper display panel 200 having the above structure, and forming a liquid crystal layer 3 including liquid crystal molecules therebetween to vertically align the liquid crystal molecules. The basic structure of the liquid crystal display according to the present invention is provided. When the thin film transistor substrate and the color filter substrate are aligned, the cutting patterns 191, 192, and 193 of the pixel electrode 190 and the cutting patterns 271, 272, and 273 of the common electrode 270 may include a plurality of small domains. Divide into These small domains are classified into four types according to the average major axis direction of the liquid crystal molecules located therein.

In this case, when a driving voltage is applied between the common electrode 270 and the pixel electrode 190, the cutting patterns 191, 192, and 193 of the pixel electrode 190 and the cutting patterns 271, 272 of the common electrode 270 are applied. A fringe field is formed by 273 so that the liquid crystal molecules are inclined in a specific direction for each small domain. In this case, the cutout pattern of the protrusion 137 of the storage electrode line 131 adjacent to the cutting patterns 191, 192, and 193 of the pixel electrode 190 and the adjacent transitions of the storage electrodes 133c and 133d of the pixel electrode 190 ( 191, 192 and 193 are formed side by side along the adjacent side to increase the strength of the fringe field to improve the inclination speed of the liquid crystal molecules, that is, the response speed and texture.

 Second Embodiment

3 is a layout view of a liquid crystal display according to a second exemplary embodiment of the present invention, and FIGS. 4A and 4B are lines IVa-IVa 'and IVb-IVb of FIG. 3 of a liquid crystal display according to the second exemplary embodiment of the present invention. Is a cross-sectional view taken along a line.

3 to 4B, the liquid crystal display according to the second embodiment is the same as the liquid crystal display according to the first embodiment, and in the domain division means of the liquid crystal display, domain division means of the upper and lower substrates. Each of these is formed in a projection pattern.

In addition, the storage electrode line 131 extends up and down and includes an extension 137 having an inclined angle of 45 ° with respect to the extended one side of the storage electrode line 131.

More specifically, when the thin film transistor substrate and the color filter substrate are aligned, the projection patterns 191, 192, and 193 formed on the pixel electrode 190 and the projection patterns 271, 272 formed on the common electrode 270 are formed. 273 divides the pixel area into a plurality of small domains. These small domains are classified into four types according to the average major axis direction of the liquid crystal molecules located therein.

In this case, when a driving voltage is applied between the common electrode 270 and the pixel electrode 190, the protrusion patterns 191, 192, and 193 of the pixel electrode 190 and the protrusion patterns 271, 272 of the common electrode 270 are applied. A fringe field is formed by 273 so that the liquid crystal molecules are inclined in a specific direction for each small domain. In this case, adjacent transitions of the extension electrodes 137 of the storage electrode lines 131 adjacent to the projection patterns 191, 192 and 193 of the pixel electrode 190 are adjacent to the projection patterns 191, 192 and 193 of the pixel electrode 190. Since the sidewalls are formed side by side, the strength of the fringe field is increased to improve the inclination speed of the liquid crystal molecules, that is, the response speed and the texture.

 Third Embodiment

5 is a layout view of a liquid crystal display according to a third exemplary embodiment of the present invention, and FIGS. 6A and 6B are lines VIa-VIa 'and VIb-VIb of FIG. 5 of a liquid crystal display according to a third exemplary embodiment of the present invention. Is a cross-sectional view taken along a line.

5 to 6B, the liquid crystal display according to the third embodiment is the same as that of the liquid crystal display according to the first embodiment, and the domain division means of the upper and lower substrates of the liquid crystal display are formed in the domain of the upper substrate. The dividing means is formed in a protrusion pattern and the domain dividing means of the lower substrate is formed in an incision pattern.

In addition, the storage electrode line 131 extends up and down and includes an extension 137 and a plurality of storage electrodes 133a to 133d having an inclination angle of 45 ° with respect to the extended one side of the storage electrode line 131. . The storage electrodes 133a to 133d extend downward and upward in a vertical direction from the storage electrode line 131, and have a length different from those of the first and second vertical portions 133a and 133b and the first vertical portion 133a. Both ends and both ends of the second vertical portion 133b are connected to each other, and have first and second diagonal portions 133c and 133d having an inclination angle of 45 ° with respect to the storage electrode line 131. In addition, the second vertical portion 133b is connected to the expansion portion 137 of the storage electrode line 131 at the center portion.

More specifically, when the thin film transistor substrate and the color filter substrate are aligned, the protrusions formed on the cutting patterns 91, 92, 93, 94, 95, and 96 formed on the pixel electrode 190 and the common electrode 270 are provided. Patterns 271, 272, 273, 274, 275, and 276 divide the pixel region into a plurality of small domains. These small domains are classified into four types according to the average major axis direction of the liquid crystal molecules located therein.

In this case, when a driving voltage is applied between the common electrode 270 and the pixel electrode 190, the cutting patterns 191, 192, and 193 of the pixel electrode 190 and the protrusion patterns 271, 272, of the common electrode 270 are applied. A fringe field is formed by 273 so that the liquid crystal molecules are inclined in a specific direction for each small domain. In this case, an incision pattern of the extended portion 137 of the storage electrode line 131 adjacent to the incision patterns 191, 192, and 193 of the pixel electrode 190 and the adjacent transition pixel electrode 190 of the storage electrodes 133c and 133d are shown. Since they are formed side by side along the adjacent sides of (191, 192, 193), the strength of the fringe field is increased to improve the inclination speed of the liquid crystal molecules, that is, the response speed and the texture.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights. In particular, the arrangement of the cutout patterns formed on the pixel electrode and the common electrode may have various variations.

Through the above configuration, the aperture ratio can be improved while preventing light leakage from the vertical alignment mode liquid crystal display.

1 is a layout view of a liquid crystal display according to a first exemplary embodiment of the present invention.

2A and 2B are cross-sectional views taken along lines IIa-IIa 'and IIb-IIb' of FIG. 1 of the liquid crystal display according to the first exemplary embodiment of the present invention.

3 is a layout view of a liquid crystal display according to a second exemplary embodiment of the present invention.

4A and 4B are cross-sectional views taken along lines IVa-IVa 'and IVb-IVb' of FIG. 3 of the liquid crystal display according to the second exemplary embodiment of the present invention.

5 is a layout view of a liquid crystal display according to a third exemplary embodiment of the present invention.

6A and 6B are cross-sectional views taken along lines VIa-VIa 'and VIb-VIb' of FIG. 5 of the liquid crystal display according to the third exemplary embodiment of the present invention.

Claims (3)

A first insulating substrate having an inner surface and an outer surface, A common electrode formed on the first insulating substrate and having a first domain dividing means, A second insulating substrate having an inner surface and an outer surface and disposed to face the inner surface and the inner surface of the first insulating substrate, A gate line formed on an inner surface of the second insulating substrate and including a gate electrode, A storage electrode line formed on an inner surface of the second insulating substrate and including a storage electrode; A gate insulating film formed on the gate line and the storage electrode line; A data line formed on the gate insulating layer and including a source electrode adjacent to the gate electrode and a drain electrode opposite to the source electrode with respect to the gate electrode; A protective film formed on the data line, A pixel electrode formed on the passivation layer with second domain dividing means and electrically connected to the drain electrode; A liquid crystal layer filled between the first insulating substrate and the second insulating substrate, The sustain electrode is formed to partially overlap with the first domain dividing means, and a side adjacent to the first domain dividing means is formed along the first domain dividing means in an overlapping portion. In claim 1, And the first domain dividing means and the second domain dividing means are formed by selecting any one of a cutting pattern and a projection pattern, respectively. The method of claim 1 or 2, And the first and second domain dividing means are disposed to have an inclination angle of 45 degrees corresponding to the sustain electrode line.