KR20060038078A - Thin film transistor array panel and multi domain liquid crystal display including the same - Google Patents

Abstract

According to an exemplary embodiment of the present invention, a liquid crystal display includes a first signal line, a second signal line insulated from and intersecting the first signal line, a pixel electrode formed for each pixel defined by the intersection of the first signal line and the second signal line, and a first signal line. A second signal line, a first display panel having a thin film transistor having three terminals connected to the pixel electrode, a second display panel having a common electrode facing the pixel electrode, and a liquid crystal layer formed between the first display panel and the second display panel; It is preferable that the pixel electrode becomes thicker or thinner as it moves away from the center. Accordingly, the liquid crystal display according to the present invention forms an inclined pixel electrode in each domain, thereby gradually changing the inclination angle of the liquid crystal molecules as the thickness of the pixel electrode changes, thereby dividing each of the four domains indefinitely. . Therefore, since the relationship curve of the transmittance with respect to the applied voltage, that is, the VT curve, differs from one infinite domain to any domain, the optical characteristics of the infinite partition within the domain are effectively compensated for each domain, thereby improving side visibility. do.

Liquid crystal display, domain control means, pixel electrode, tilt, taper

Description

Thin film transistor array panel and multi-domain liquid crystal display including the same {THIN FILM TRANSISTOR ARRAY PANEL AND MULTI DOMAIN LIQUID CRYSTAL DISPLAY INCLUDING THE SAME}

1 is a layout view of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a layout view of an opposing display panel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a layout view of a liquid crystal display according to an exemplary embodiment of the present invention including the two display panels of FIGS. 1 and 2.

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

FIG. 5 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line IV-IV ′ of FIG. 3.

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

FIG. 7 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line VII-VII ′. FIG.

FIG. 8 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line VII-VII ′ of FIG. 6.                 

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

FIG. 10 is a cross-sectional view of the liquid crystal display of FIG. 9 taken along the line X-X '.

FIG. 11 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line X-X ′ of FIG. 10.

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

110: substrate 121, 129: gate line

124: gate electrode 140: gate insulating film

151 and 154: semiconductors 161 and 165: ohmic contact members

171 and 179: data line 173: source electrode

175: drain electrode 180: protective film

181, 182, and 185: contact hole 190: pixel electrode

81, 82: contact auxiliary member 270: common electrode

91, 92a, 92b, 271, 272a, 272b: incision

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor array panel and a liquid crystal display including the same, and more particularly, to a thin film transistor array panel that divides a pixel into a plurality of domains to obtain a wide viewing angle, and a liquid crystal display including the same.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode and a color filter 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. In order to overcome these disadvantages, various methods for widening the viewing angle have been developed. Among them, the liquid crystal molecules are oriented vertically with respect to the upper and lower substrates, and the pixel is formed by forming a constant incision pattern or protrusion on the pixel electrode and the common electrode as the opposite electrode. The method of dividing the into multiple domains has been considered to be effective.

The liquid crystal display of the vertical alignment mode having such protrusions or incision patterns has a contrast ratio reference viewing angle based on a contrast ratio of 1:10 or a gray scale inversion reference viewing angle defined as a limit angle of luminance inversion between gray scales. Very good at over 80 °. However, the gamma curve of the front side and the gamma curve of the side do not coincide with each other, resulting in inferior visibility in the left and right sides. For example, in the Patterned Vertically Aligned (PVA) mode, which makes an incision by domain dividing means, the screen looks brighter toward the side and the color tends to shift toward white. Occasionally, the picture appears clumped and disappears. However, as liquid crystal display devices are used for multimedia in recent years, visibility has become increasingly important as pictures and moving pictures are viewed.                         

In order to improve such visibility, a two-division differential voltage application structure is used, in which four domains are divided into two of a main pixel and a sub pixel, respectively, but the aperture ratio is reduced in a pixel structure of two or more divisions. There is this. That is, the two-division structure of the four-domain main pixel and the sub-pixel is divided into eight pixels, the four-domain three-division structure is divided into 12 pixels, and the four-domain four-division structure is divided into 16 pixels. Although the visibility can be improved by increasing the division, a problem of decreasing the aperture ratio due to pixel division also occurs.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a thin film transistor array panel and a liquid crystal display including the same, which can improve visibility by minimizing aperture ratio while minimizing the effect of infinite division.

The thin film transistor array panel according to the present invention includes an insulating substrate, a first signal line formed on the insulating substrate, a second signal line insulated from and intersecting the first signal line, and an angle defined by the first signal line and the second signal line crossing each other. And a thin film transistor having three terminals electrically connected to the pixel electrode, the first signal line, the second signal line, and the pixel electrode, which are formed for each pixel, and the pixel electrode gradually thickens as it moves away from the center. It is desirable to be thin.

In addition, the thickest part of the pixel electrode is preferably 1.1 to 100,000,000 times the thinnest part.                     

In addition, the area occupied by the pixel electrode is preferably 0.1 to 1.0 times the pixel area.

In addition, the pixel electrode has a cutout, and the center of the pixel electrode preferably overlaps the cutout.

In addition, the opposing display panel according to the present invention may include an insulating substrate and a common electrode formed entirely on the insulating substrate, and the common electrode may gradually become thicker or thinner as it moves away from the center.

The common electrode preferably has a cutout, and the center of the common electrode preferably overlaps the cutout.

In addition, the liquid crystal display according to the present invention includes a first signal line, a second signal line insulated from and intersecting the first signal line, a pixel electrode formed for each pixel defined by the first signal line and the second signal line crossing each other; A first display panel having a thin film transistor having three terminals connected to the first signal line, the second signal line, and the pixel electrode; a second display panel having a common electrode facing the pixel electrode; and the first display panel and the second display panel. It includes a liquid crystal layer formed between, the pixel electrode is preferably thicker or thinner as it moves away from the center.

In addition, it is preferable that the common electrode is gradually thickened or thinned away from the center.

The display device may further include a plurality of domain regulating means formed on at least one side of the first display panel and the second display panel and dividing the pixels into a plurality of domains.

In addition, the domain restricting means is preferably a cutout portion of the pixel electrode.

In addition, it is preferable that the domain regulating means is a cutout portion of the common electrode.

In addition, the center of the pixel electrode preferably overlaps the cutout of the pixel electrode.

In addition, it is preferable that the center of the common electrode overlaps the cutout of the common electrode.

Then, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can 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.

Now, a thin film transistor array panel and a liquid crystal display including the same according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a layout view showing a structure of a thin film transistor array panel for a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a layout view showing a structure of an opposing display panel for a liquid crystal display according to an exemplary embodiment of the present invention. 3 is a layout view illustrating a structure of a liquid crystal display according to an exemplary embodiment in which the display panels of FIGS. 1 and 2 are aligned, and FIG. 4 is a line IV-IV 'of the liquid crystal display of FIG. It is a cross-sectional view cut along.

1 to 4, the liquid crystal display according to the exemplary embodiment of the present invention is formed between the thin film transistor array panel 100 on the lower side and the upper opposing display panel 200 facing the same and between them. The liquid crystal layer 3 includes liquid crystal molecules 31 that are substantially perpendicular to the two display panels 100 and 200. In this case, alignment layers 11 and 21 are formed on each of the display panels 100 and 200, and the alignment layers 11 and 21 perpendicular to the liquid crystal molecules 31 of the liquid crystal layer 3 with respect to the display panels 100 and 200. It is preferred, but not necessarily, that it is a vertical orientation mode that allows it to be oriented. In addition, upper and lower polarizers 22 and 12 are attached to outer surfaces of the upper panel 200 and the lower panel 100, respectively.

The thin film transistor array panel 100 made of a transparent insulating material such as glass is made of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or an organic conductive material, and the cutouts 91, 92a and 92b are formed. A pixel electrode 190 is formed, and each pixel electrode 190 is connected to a thin film transistor to receive an image signal voltage. In this case, the thin film transistor is connected to the gate line 121 for transmitting the scan signal and the data line 171 for transmitting the image signal, respectively, to turn on and off the pixel electrode 190 according to the scan signal. . Here, the pixel electrode 190 may not be made of a transparent material in the case of a reflective liquid crystal display, and in this case, the lower polarizer 12 is also unnecessary.

It is also made of a transparent insulating material such as glass, and the opposite display panel 200 facing the thin film transistor array panel 100 includes a black matrix 220 and a color filter of red, green, and blue to prevent light leakage from the edge of the pixel. The common electrode 270 formed of the transparent conductive material such as 230 and ITO or IZO is formed. The black matrix 220 may be formed not only in the peripheral portion of the pixel region but also in the portion overlapping the cutouts 271, 272a and 272b of the common electrode 270. This is to prevent light leakage caused by the cutouts 271, 272a and 272b.

Next, the thin film transistor array panel 100 will be described in more detail.

In the thin film transistor array panel 100, a plurality of gate lines 121 may be formed on the lower insulating substrate 110 to transfer gate signals. The gate line 121 mainly extends in the horizontal direction, and a part of each gate line 121 forms a plurality of gate electrodes 124. The gate electrode 124 is formed in the form of a protrusion in the gate line 121, and as shown in the present embodiment, the gate line 121 may have a contact portion for transmitting a gate signal from the outside to the gate line 121. In this case, the end portion 129 of the gate line 121 has a wider width than other portions, but otherwise, the end portion of the gate line 121 is directly formed on the substrate 110. It is directly connected to the output terminal of.

The storage electrode wirings are formed on the insulating substrate 110 in the same layer as the gate lines 121. Each storage electrode wiring includes a storage electrode line 131 extending in parallel with the gate line 121 at the edge of the pixel area and a plurality of storage electrodes 133a, 133b, 133c, and 133d extending therefrom. The pair of storage electrodes 133a, 133b, 133c, and 133d extend in the vertical direction and are connected to each other by the vertical electrode 133a and 133b which are connected to each other by the storage electrode line 131 extending in the horizontal direction, and the pixel electrode formed thereafter ( An oblique portion 133c and 133d overlapping the cutouts 191 and 193 of 190 and connecting the vertical portions 133a and 133b. In this case, the sustain electrode wiring may not have a pair of sustain electrodes 133a, 133b, 133c, and 133d, and may be modified into various shapes as necessary.

The gate line 121 and the sustain electrode wirings 131, 133a, 133b, 133c, and 133d are made of metal such as Al, Al alloy, Ag, Ag alloy, Cr, Ti, Ta, Mo, or the like. As shown in FIG. 4, the gate line 121 and the sustain electrode wirings 131, 133a, 133b, 133c, and 133d of the present embodiment are formed of a single layer, but have excellent physicochemical properties such as Cr, Mo, Ti, Ta, and the like. It may be made of a double layer including a metal layer of the Al-based or Ag-based metal layer having a low specific resistance. In addition, the gate line 121 and the sustain electrode wirings 131, 133a, 133b, 133c, and 133d may be made of various metals or conductors.

Side surfaces of the gate line 121 and the sustain electrode wirings 131, 133a, 133b, 133c, and 133d are inclined, and the inclination angle with respect to the horizontal plane is preferably 30 to 80 °.

A gate insulating layer 140 made of silicon nitride (SiNx) or the like is formed on the gate line 121 and the storage electrode wirings 131, 133a, 133b, 133c, and 133d.

A plurality of drain electrodes 175, including a plurality of data lines 171, are formed on the gate insulating layer 140. Each data line 171 extends mainly in a vertical direction and has a source electrode 173 extending from the data line 171 by extending a plurality of branches toward each drain electrode 175. One end portion 179 of the data line 171 transfers an image signal from the outside to the data line 171.

In addition, a leg metal piece 172 overlapping the gate line 121 is formed on the gate insulating layer 140.

Like the gate line 121, the data line 171 and the drain electrode 175 may be made of various conductive materials such as chromium and aluminum, and may be formed of a single layer or multiple layers.

Under the data line 171 and the drain electrode 175, a plurality of linear semiconductors 151 that extend mainly vertically along the data line 171 are formed. Each linear semiconductor 151 made of amorphous silicon extends toward each gate electrode 124, the source electrode 173, and the drain electrode 175 to have a channel portion 154.

Between the semiconductor 151, the data line 171, and the drain electrode 175, a plurality of linear ohmic contacts 161 and island-like ohmic contacts 165 for reducing contact resistance therebetween, respectively. Is formed. The ohmic contact 161 is made of amorphous silicon doped with silicide or n-type impurities at a high concentration, and has an ohmic contact 163 extending into a branch, and the island-type ohmic contact 165 has a gate electrode 124. Facing the ohmic contact 163.

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

The passivation layer 180 includes a plurality of contact holes 185 and 182 exposing at least a portion of the drain electrode 175 and an end portion 179 of the data line 171, respectively. Meanwhile, the end portion 129 of the gate line 121 also has a contact portion for connecting with an external driving circuit, and the plurality of contact holes 181 pass through the gate insulating layer 140 and the passivation layer 180 to pass through the gate line. Expose the end 129 of 121.

A plurality of data contact assistant members and gate contact assistants 82 and 81 are formed on the passivation layer 180, including a plurality of pixel electrodes 190. The pixel electrode 190 and the data contact assistant members and the gate contact assistant members 81 and 82 may be formed of a transparent conductor such as indium tin oxide (ITO), indium zinc oxide (IZO), or an organic conductive material, or light such as aluminum (Al). It is formed using an opaque conductor having excellent reflection characteristics.

The pixel electrode 190 has a tapered or inverse tapered structure and has a predetermined inclination angle θ. That is, the thickness of the pixel electrode 190 formed in each of the four domains divided into the cutouts 91, 92a, 92b, 271, 272a, and 272b varies continuously.

The pixel electrode 190 gradually decreases in thickness in both or one directions with respect to the horizontal plane with respect to the cutouts 91, 92a, and 92b.

That is, the center of the pixel electrode 190 is the thickest portion 190a, and the thickest portion 190a of the pixel electrode 190 is preferably 1.1 times 100,000,000 times the thinnest portion, and the pixel electrode 190 ) Occupies an area of 0.1 to 1.0 times the pixel area.

Meanwhile, although cutouts 91, 92a, and 92b are formed in the pixel electrode 190 in FIG. 4, a structure in which the cutout is not formed in the pixel electrode 190 may be possible.

In addition, a storage wiring connecting bridge 84 is formed on the same layer as the pixel electrode 190 to connect the storage electrode 133a and the storage electrode line 131 of the pixels adjacent to each other across the gate line 121. The storage wiring connecting bridge 84 is in contact with the storage electrode 133a and the storage electrode line 131 through the contact holes 183 and 184 formed over the passivation layer 180 and the gate insulating layer 140. The sustain wiring connection leg 84 overlaps the leg metal piece 172, and these may be electrically connected to each other. The sustain wiring connection bridge 84 serves to electrically connect the entire sustain wiring on the lower substrate 110. This holding wiring can be used to repair the defect of the gate line 121 or the data line 171, if necessary, and the leg metal piece 172 is held with the gate line 121 when irradiating a laser for such repair. It is formed to assist the electrical connection of the wiring connection bridge (84).                     

In addition, an insulating material is formed on the thin film transistor array panel 100, and a substrate spacer 320 is formed to maintain a constant gap between the two display panels 100 and 200.

In the opposite display panel 200 facing the thin film transistor array panel 100, a black matrix 220 is formed on the upper insulating substrate 210 to prevent light leakage from the pixel edge. The red, green, and blue color filters 230 are formed on the black matrix 220. The planarization film 250 is formed on the entire surface of the color filter 230, and a common electrode 270 having cutouts 271, 272a, and 272b is formed thereon. The common electrode 270 is formed of a transparent conductor such as ITO or indium zinc oxide (IZO).

A pair of cutouts 271, 272a, and 272b of the common electrode 270 forms portions 45a with respect to the gate line 121 among the cutouts 91, 92a and 92b of the pixel electrode 190. 92b) and alternately arranged side by side with an oblique line portion and an end portion overlapping the side of the pixel electrode 190. At this time, the end is classified into a longitudinal end part and a horizontal end part.

When the thin film transistor substrate and the opposing display panel having the above structure are aligned and combined, and a liquid crystal material is injected and vertically aligned therebetween, a basic structure of the liquid crystal display according to the present invention is provided.

After the thin film transistor array panel 100 and the opposing display panel 200 are aligned, the liquid crystal molecules of the pixel may be cut outs 91, 92a, 92b, and 271 while an electric field is applied to the common electrode 270 and the pixel electrode 190. , 272a, 272b and a fringe field formed at the edge boundary of the pixel electrode 190 are divided into a plurality of domains. Liquid crystal molecules located inside these domains are classified into four types along their average major axis directions, and each domain is elongated to have a width and a length.

Therefore, the cutouts 91, 92a and 92b of the pixel electrode 190 and the cutouts 271, 272a and 272b of the common electrode 270 act as domain regulating means for splitting and aligning the liquid crystal molecules. For example, a protrusion may be formed of an inorganic material or an organic material on or below the pixel electrode 190 and the common electrode 270 instead of the cutouts 91, 92a, 92b, 271, 272a, and 272b.

In this case, the thick portion 190a of the pixel electrode 190 has a small cell gap d, and thus the electric field intensity increases when a voltage is applied, and the thin portion 190b of the pixel electrode 190 has a large thickness. Since the intensity of the electric field decreases, the distribution of the intensity of the electric field is continuously changed along the inclined surface of the pixel electrode 190.

Therefore, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 190a of the pixel electrode 190 has a small angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align almost to the horizontal alignment. The inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 310b of the pixel electrode 190 has a large angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align near the vertical alignment.

That is, the liquid crystal molecules 310 lie at different inclination angles in the direction in which the domains are divided due to the change in the equipotential line due to the cell gap difference caused by the thickness difference of the pixel electrode 190.                     

As described above, as the thickness of the pixel electrode 190 becomes thinner, the inclination angle of the liquid crystal molecules 31 gradually increases, and as the thickness of the pixel electrode 190 becomes thicker, the inclination angle of the liquid crystal molecules 31 becomes gradually smaller. . Therefore, as the thickness of the pixel electrode 190 changes, the inclination angle of the liquid crystal molecules 31 gradually changes, thereby making it possible to divide each of the four domains indefinitely.

Therefore, since the relationship curve of the transmittance with respect to the applied voltage, i.e., the VT curve, is different from each other for each infinite division of one domain, the optical characteristics of the infinite division within the domain are effectively effective for each domain. Compensated to improve side visibility. That is, the side gamma curve distortion phenomenon in which the gamma curve on the front side and the gamma curve on the side do not coincide is prevented, thereby improving visibility on the left and right sides.

Meanwhile, in another embodiment of the present invention, the pixel electrode of the liquid crystal display may have a different shape, and one embodiment will be described in detail with reference to the drawings.

FIG. 5 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line IV-IV ′ of FIG. 3.

As shown in FIG. 5, the layer structure of the thin film transistor array panel of the liquid crystal display according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel of the liquid crystal display shown in FIGS. 1 to 4. However, the pixel electrode 190 gradually increases in thickness in both or one directions with respect to the cutouts 91, 92a, and 92b with respect to the horizontal plane. That is, the center of the pixel electrode 190 is the thinnest portion 190b and overlaps the cutouts 91, 92a and 92b.

Even in this case, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 190a of the pixel electrode 190 has a small angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align almost to the horizontal alignment. The inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 310b of the pixel electrode 190 has a large angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align near the vertical alignment.

Meanwhile, although cutouts 91, 92a, and 92b are formed in the pixel electrode 190 in FIG. 5, a structure in which the cutouts are not formed in the pixel electrode 190 is also possible.

Meanwhile, in the exemplary embodiment of the present invention, the thin film transistor array panel may have a different shape, the common electrode of the opposing display panel may be formed to be inclined, and one embodiment will be described in detail with reference to the drawings.

FIG. 6 is a layout view of a liquid crystal display including a thin film transistor array panel according to another exemplary embodiment. FIG. 7 is a cross-sectional view of the liquid crystal display of FIG. 6 taken along the line VII-VII ′.

6 and 7, the layer structure of the thin film transistor array panel of the liquid crystal display according to the present exemplary embodiment is generally the same as the layer structure of the thin film transistor array panel of the liquid crystal display shown in FIGS. 1 to 4. That is, the plurality of linear semiconductors including the plurality of gate lines 121 including the plurality of gate electrodes 124 is formed on the substrate 110, and the gate insulating layer 140 and the plurality of protrusions 154 thereon. 151, a plurality of linear ohmic contact members 161 each including a plurality of protrusions 163, and a plurality of island type ohmic contact members 165 are sequentially formed. A plurality of data lines 171 including a plurality of source electrodes 173 and a plurality of drain electrodes 175 are formed on the ohmic contacts 161 and 165 and the gate insulating layer 140, and the passivation layer 180 is formed thereon. Is formed. A plurality of contact holes 182, 181, and 185 are formed in the passivation layer 180 and / or the gate insulating layer 140, and the pixel electrode 190 and the contact auxiliary members 81 and 82 are formed thereon. .

However, the semiconductor 151 has a planar shape substantially the same as the data line 171, the drain electrode 175, and the ohmic contacts 161 and 165, except for the protrusion 154 where the thin film transistor is located. Have. In detail, the linear semiconductor 151 may include the source electrode 173 and the drain electrode 175 in addition to the data line 171, the drain electrode 175, and the portions below the ohmic contacts 161 and 165. ) Has an exposed portion between them.

The thin film transistor array panel of the liquid crystal display according to another exemplary embodiment of the present invention is patterned together in a photolithography process using a photoresist pattern having a different thickness depending on the position of the data line 171 and the semiconductor 151 in the manufacturing process. It is formed by.

The common electrode 270 of the opposing display panel 200 has a tapered or inverse tapered structure to have a predetermined inclination angle θ. That is, the thickness of the common electrode 270 formed in each of the four domains divided into the cutouts 91, 92a, 92b, 271, 272a, and 272b varies continuously.

The common electrode 270 gradually decreases in thickness in both or one directions with respect to the cutouts 271, 272a and 272b with respect to the horizontal plane. That is, the center of the common electrode 270 is the thickest portion 270a and overlaps the cutouts 271, 272a and 272b. The thickest part of the common electrode 270 is preferably 1.1 times 100,000,000 times the thinnest part, and the area occupied by the common electrode 270 is preferably 0.1 times 1.0 times the pixel area.

In this case, the thicker portion 270a of the common electrode 270 has a smaller cell gap d, so the electric field is increased when a voltage is applied, and the thinner portion 270b of the common electrode 270 is thick. Since the intensity of the electric field decreases, the distribution of the electric field is continuously changed along the inclined surface of the common electrode 270.

Therefore, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 270a of the common electrode 270 has a small angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align almost to the horizontal alignment. The inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 380b of the common electrode 270 has a large angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align near the vertical alignment.

That is, the liquid crystal molecules 310 lie at different inclination angles in the direction in which the domains are divided due to the change in the equipotential line due to the cell gap difference due to the thickness difference of the common electrode 270.

As described above, as the thickness of the common electrode 270 becomes thinner, the inclination angle of the liquid crystal molecules 31 gradually increases, and as the thickness of the common electrode 270 becomes thicker, the inclination angle of the liquid crystal molecules 31 becomes gradually smaller. . Therefore, as the thickness of the common electrode 270 changes, the inclination angle of the liquid crystal molecules 31 gradually changes, and thus it is possible to divide each of the four domains indefinitely.

Therefore, since the relationship curve of the transmittance with respect to the applied voltage, i.e., the VT curve, is different from each other for each infinite division of one domain, the optical characteristics of the infinite division within the domain are effectively effective for each domain. Compensated to improve side visibility.

Meanwhile, although cutouts 271, 272a, and 272b are formed in the common electrode 270 in FIG. 7, a structure in which the cutouts are not formed in the common electrode 270 is possible.

Meanwhile, in another embodiment of the present invention, the common electrode of the liquid crystal display may have a different shape, and one embodiment will be described in detail with reference to the drawings.

FIG. 8 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line VII-VII ′ of FIG. 6.

As shown in FIG. 8, the layer structure of the thin film transistor array panel of the liquid crystal display according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel of the liquid crystal display shown in FIGS. 6 to 7. However, the common electrode 270 of the opposing display panel becomes thicker gradually in both or one directions with respect to the cutouts 271, 272a and 272b with respect to the horizontal plane. That is, the center of the common electrode 270 is the thinnest portion 270b and overlaps the cutouts 271, 272a and 272b.

Even in this case, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 270a of the common electrode 270 has a small angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align almost to the horizontal alignment. In addition, the inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 380b of the inclined film 380 has a large angle with respect to the horizontal plane. That is, the liquid crystal molecules 31 align near the vertical alignment.

8, cutouts 271, 272a, and 272b are formed in the common electrode 270, but a structure in which the cutouts are not formed in the common electrode 270 is also possible.

Meanwhile, although the color filter 230 is disposed on the opposing display panel 200 in the structure of the liquid crystal display device, the color filter 230 may be disposed on the thin film transistor array panel 100. In this case, the gate insulating layer 140 or the passivation layer 180 may be disposed. It may be formed at the bottom of the. In addition, both the pixel electrode of the thin film transistor array panel and the common electrode of the opposing display panel may be formed to be inclined. This embodiment will be described in detail with reference to the accompanying drawings.

FIG. 9 is a layout view of a liquid crystal display according to another exemplary embodiment. FIG. 10 is a cross-sectional view of the liquid crystal display of FIG. 9 taken along line X-X ′.

As shown in FIG. 9 and FIG. 10, the layer structure of the thin film transistor array panel for a liquid crystal display device according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel for liquid crystal display devices shown in FIGS.

However, red, green, and blue color filters 230R, 230G, and 230B are sequentially formed in the pixel under the passivation layer 180. The red, green, and blue color filters 230R, 230G, and 230B each have a boundary above the data line 171 and are vertically formed along the pixel column, and neighboring color filters are disposed on the data line 171. Since the parts overlap each other, a hill may be formed on the data line 171. In this case, the red, green, and blue color filters 230R, 230G, and 230B overlapping each other may have a function of a black matrix that blocks light leaking between neighboring pixel areas. Therefore, only the common electrode 270 may be formed on the opposing display panel for the liquid crystal display according to the present exemplary embodiment by omitting the black matrix.

In addition, a pixel electrode 190 having a predetermined inclination angle θ is formed on the pixel electrode 190 of the thin film transistor array panel in a tapered or inverse taper structure. The pixel electrode 190 of the thin film transistor array panel gradually decreases in thickness in both or one directions with respect to the cutouts 91, 92a, and 92b with respect to the horizontal plane. That is, the center of the pixel electrode 190 is the thickest portion 190a and overlaps the cutouts 91, 92a and 92b.

The common electrode 270 of the opposing display panel is gradually thicker in both or one directions with respect to the cutouts 271, 272a and 272b with respect to the horizontal plane. That is, the center of the common electrode 270 is the thinnest portion 270b, overlaps the cutouts 271, 272a and 272b of the common electrode 270, and has the thickest thickness among the common electrodes 270. The portion 270a corresponds to the cutouts 91, 92a and 92b of the pixel electrode 190.

In this case, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 190a of the pixel electrode 190 and the thick portion 270a of the common electrode 270 may have a small angle with respect to the horizontal plane. Have That is, the liquid crystal molecules 31 align almost to the horizontal alignment. In addition, the inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 190b of the pixel electrode 190 and the thin portion 270a of the common electrode 270 has a large angle with respect to the horizontal plane. . That is, the liquid crystal molecules 31 align near the vertical alignment.

As described above, since both the pixel electrode of the thin film transistor array panel and the common electrode of the opposing display panel are formed to be inclined, the effect of improving the visibility becomes more prominent.

Meanwhile, in another embodiment of the present invention, the pixel electrode and the common electrode of the liquid crystal display may have different shapes, and one embodiment will be described in detail with reference to the drawings.

FIG. 11 is a cross-sectional view of a liquid crystal display according to another exemplary embodiment taken along the line X-X ′ of FIG. 10.

As shown in FIG. 11, the layer structure of the thin film transistor array panel of the liquid crystal display according to the present embodiment is generally the same as the layer structure of the thin film transistor array panel of the liquid crystal display shown in FIG. However, the pixel electrode 190 of the thin film transistor array panel gradually increases in thickness in both or one directions with respect to the cutouts 91, 92a, and 92b with respect to the horizontal plane. That is, the center of the pixel electrode 190 is the thinnest portion 190a and overlaps the cutouts 91, 92a and 92b.

The common electrode 270 of the opposing display panel is gradually thinner in both directions or one direction with respect to the cutouts 271, 272a and 272b with respect to the horizontal plane. That is, the center of the common electrode 270 of the opposing display panel overlaps the cutouts 271, 272a and 272b.

In this case, the inclination angle θ2 of the liquid crystal molecules 31 positioned in the thick portion 190a of the pixel electrode 190 and the thick portion 270a of the common electrode 270 may have a small angle with respect to the horizontal plane. Have That is, the liquid crystal molecules 31 align almost to the horizontal alignment. In addition, the inclination angle θ1 of the liquid crystal molecules 31 positioned in the thin portion 190b of the pixel electrode 190 and the thin portion 270b of the common electrode 270 has a large angle with respect to the horizontal plane. . That is, the liquid crystal molecules 31 align near the vertical alignment.

In the exemplary embodiment of the present invention, only the liquid crystal display device in the vertical alignment mode in which the liquid crystal molecules are arranged vertically with respect to the two display panels 100 and 200 is described. Twisted nematic mode in which the liquid crystal molecules are arranged in parallel and spirally twisted, and planar driving method in which the common electrode and the pixel electrode are arranged on the same display panel to drive the liquid crystal molecules arranged in parallel to the display panel. It can be applied to various types of liquid crystal display devices such as plane switching mode.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

In the liquid crystal display according to the present invention, the inclination angles of the liquid crystal molecules are gradually changed as the thickness of the pixel electrode or the common electrode is changed by forming the pixel electrode or the common electrode having the inclination in each of the domains. Split infinitely Therefore, since the relationship curve of the transmittance with respect to the applied voltage, that is, the VT curve, differs from one infinite domain to any domain, the optical characteristics of the infinite partition within the domain are effectively compensated for each domain, thereby improving side visibility. do.

In addition, the visibility can be improved by achieving the effect of infinite division while minimizing the reduction of the aperture ratio.

Claims (15)

Insulation board, A first signal line formed on the insulating substrate, A second signal line insulated from and intersecting the first signal line, A pixel electrode formed for each pixel defined by the crossing of the first signal line and the second signal line; A thin film transistor having three terminals electrically connected to the first signal line, the second signal line, and the pixel electrode, respectively. Including, The pixel electrode gradually thickens or becomes thinner as the pixel electrode moves away from the center. In claim 1, The thickest portion of the pixel electrode is 1.1 to 100,000,000 times the thinnest portion of the thin film transistor array panel. In claim 1, And an area occupied by the pixel electrode is 0.1 to 1.0 times the pixel area. In claim 1, The pixel electrode has a cutout. In claim 1, And a center of the pixel electrode overlaps the cutout. Insulation board, A common electrode formed on the insulating substrate Including, And the common electrode is gradually thickened or thinned away from the center thereof. In claim 6, And the common electrode has a cutout. In claim 6, A center of the common electrode overlapping the cutout; A first signal line, a second signal line insulated from and intersecting the first signal line, a pixel electrode formed for each pixel defined by the first signal line and the second signal line intersecting, the first signal line, and the second signal line A first display panel having a thin film transistor having three terminals connected to the pixel electrode; A second display panel on which the common electrode facing the pixel electrode is formed; Liquid crystal layer formed between the first display panel and the second display panel Including, The pixel electrode becomes thicker or thinner as it moves away from the center. In claim 9, And the common electrode is gradually thickened or thinned away from the center thereof. In claim 9, A plurality of domain restricting means formed on at least one side of the first display panel and the second display panel to divide and arrange the pixels into a plurality of domains; Liquid crystal display further comprising. In claim 9, And the domain regulating means is a cutout portion of the pixel electrode. In claim 9, And the domain regulating means is a cutout portion of the common electrode. In claim 12, The center of the pixel electrode overlaps the cutout of the pixel electrode. In claim 13, The center of the common electrode overlaps the cutout of the common electrode.

Images