KR20010046327A - A liquid crystal display, a panel for the same, and a manufacturing method of the same - Google Patents

Abstract

PURPOSE: A liquid crystal display, a substrate for the same and a method of manufacturing the liquid crystal display are to decrease failures of a PVA(Patterned vertically aligned) mode LCD and increase the aperture ratio. CONSTITUTION: A gate line(20) is formed on the first insulating substrate along the first direction. A data line(40) is formed on the first insulating substrate, is insulated from the gate line and is crossed with the gate line. A pixel electrode(50) is disposed at a region defined by adjacent two gate lines and adjacent two data lines and includes multiple linear branches(51,52) and a stem(53) connecting the branches. A switching element transfers or shuts a signal of the data line into the pixel electrode depending on a signal of the gate line. The second insulating substrate faces the first insulating substrate. A common electrode is formed on the second insulating substrate.

Description

A liquid crystal display device and a substrate used therefor and a method for manufacturing the same {A LIQUID CRYSTAL DISPLAY, A PANEL FOR THE SAME, AND A MANUFACTURING METHOD OF THE SAME}

The present invention relates to a liquid crystal display, a panel used for the same, and a manufacturing method thereof.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which an opposite 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.

Among them, the vertical alignment mode liquid crystal display in which the long axis of the liquid crystal molecules are arranged perpendicular to the upper and lower substrates without an electric field is applied, and thus, the contrast ratio is large and the wide viewing angle is easily realized.

In the vertical alignment mode liquid crystal display, a means for implementing a wide viewing angle includes a method of forming an opening pattern (patterned vertically aligned) mode and an protrusion in an electrode. All of these are methods of securing a wide viewing angle by forming a fringe field to evenly distribute the tilting direction of the liquid crystal in four directions.

Among these, the PVA mode is easy to form a fringe field of a desired shape. However, in order to form an opening pattern on the transparent electrode formed on the color filter substrate, a process of performing photolithography on indium tin oxide (ITO) should be added. In addition, an overcoat film must be formed between the color filter and the ITO electrode in order to prevent the color filter from being damaged in the process of etching ITO. Thus, the process becomes complicated and the manufacturing cost increases. In addition, the film quality of the ITO electrode on the color filter substrate side is inferior to that of the ITO electrode on the thin film transistor substrate side. Therefore, the etching characteristics are unstable, and it is difficult to form the opening pattern accurately in the desired shape. This can lead to defects.

Another disadvantage of the PVA mode is that the aperture ratio decreases because light is blocked at the portion where the aperture pattern is formed. As the width of the opening pattern is larger, the fringe field is more reliably formed, but the opening ratio is reduced accordingly.

An object of the present invention is to simplify the manufacturing process of the vertical alignment mode liquid crystal display device.

Another object of the present invention is to reduce the defect of the vertical alignment mode liquid crystal display device.

Another object of the present invention is to increase the aperture ratio of the vertical alignment mode liquid crystal display device.

1A and 1B are layout views of liquid crystal display devices according to first and second embodiments of the present invention, respectively.

FIG. 1C is a cross-sectional view taken along line Ic-Ic ′ of FIGS. 1A and 1B.

2A and 2B are layout views of the liquid crystal display according to the third and fourth embodiments of the present invention, respectively.

FIG. 2C is a cross-sectional view taken along line IIc-IIc ′ of FIGS. 2A and 2B.

3A and 3B are layout views of the liquid crystal display according to the fifth and sixth embodiments of the present invention, respectively.

3C is a cross-sectional view taken along line IIIc-IIIc 'of FIGS. 3A and 3B.

4A and 4B are layout views of the liquid crystal display according to the seventh and eighth embodiments of the present invention, respectively.

4C is a cross-sectional view taken along line IVc-IVc 'of FIGS. 4A and 4B.

In order to solve this problem, in the present invention, a pixel electrode including a plurality of linear branches and a stem connecting the same is formed on a first substrate, and an opposite electrode is formed on a second substrate facing the first substrate.

Specifically, a gate line is formed on the first substrate in the first direction, and the data line is insulated from and intersected with the gate line. A pixel electrode including a plurality of linear branches and a stem portion connecting the linear branches is formed in an area where two adjacent gate lines intersect the data line, and the signal of the data line is transmitted to the pixel electrode according to the signal of the gate line. The switching element which cuts off is formed. The second insulating substrate is opposed to the first insulating substrate, and a counter electrode is formed on the second insulating substrate. .

In this case, the branch part of the pixel electrode may include a first direction branch part and a second direction branch part different from the first direction, the first direction and the second direction may form 90 °, and the first direction may include data. It can be parallel to the line or at 45 ° to the data line. The pixel electrode may be formed of the same material on the same layer as the data line, and the switching element may be a thin film transistor. It is preferable that the liquid crystal molecules injected between the substrates are vertically aligned with respect to the substrates. The common electrode wiring may be further formed on the first insulating substrate, and the common electrode wiring may be formed of the same material on the same layer as the gate wiring.

A liquid crystal display having such a structure includes forming a gate wiring on an insulating substrate, laminating a gate insulating film, a semiconductor layer and a contact layer on the gate wiring, and patterning the contact layer and the semiconductor layer to form a contact layer pattern and a semiconductor pattern. The method may include forming a pixel electrode along with the data line, separating the source electrode contact layer and the drain electrode contact layer by etching the contact layer pattern, and forming a passivation layer.

The common electrode wiring and the gate line extending in the first direction are formed on the first substrate, and the data line is insulated from and intersects the gate line. A pixel electrode having a first opening pattern is formed in an area where two adjacent gate lines and a data line cross each other, and a switching element is formed. At this time, the common electrode overlaps the first opening pattern of the pixel electrode.

In this case, the common electrode may be wider or narrower in width than the first opening pattern.

The liquid crystal display may further include a second substrate facing the first substrate and a second common electrode formed on the second substrate and having a second opening pattern.

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

1A and 1B are layout views of a liquid crystal display device according to first and second embodiments of the present invention, respectively, and FIG. 1C is a cross-sectional view taken along line Ic-Ic 'of FIGS. 1A and 1B.

First, referring to FIGS. 1A and 1C, the gate line 20 extends in the horizontal direction on the lower insulating substrate 10, and the gate electrode 21 is formed in the form of a protrusion on the gate line 20. A gate insulating film 30 is formed on the gate wiring including the gate electrode 21 and the gate line 20. The semiconductor pattern 60, which functions as a channel portion of the thin film transistor, is formed on the gate insulating layer 30 on the gate electrode 21. On the semiconductor pattern 60, contact layer patterns (not shown) separated on both sides are formed. At this time, the semiconductor pattern 60 is made of amorphous silicon, and the contact layer pattern is made of amorphous silicon heavily doped with N-type impurities.

The data line 40 extends in the vertical direction on the gate insulating film 30, and the source electrode 41 is formed on the data line 40 as a branch. The source electrode 41 extends over one contact layer pattern. A drain electrode 42 is formed on the other contact layer pattern, and the drain electrode is connected to the pixel electrode 50. The thin film transistor including the gate electrode 21, the semiconductor pattern 60, the contact layer pattern, the source electrode 41, the drain electrode 42, and the like may have a data line 40 according to a scan signal transmitted through the gate line 20. ) Is a switching element that transfers or blocks the image signal transmitted along the line) to the pixel electrode 50. The switching element may be formed using polycrystalline silicon.

The pixel electrode 50 includes a vertical branch portion 51, a horizontal branch portion 52, and a stem portion 53 connecting the branch portions 51 and 52 that are linearly formed. The pixel electrode 50 is formed of the same material as the data line 40.

The passivation layer 70 is formed on the pixel electrode 50 and the data line 40. The passivation layer 70 protects the semiconductor pattern exposed between the source electrode 41 and the drain electrode 42.

The counter electrode 90 is formed in the upper substrate 80 over the entire surface. The counter electrode 90 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Color filters (not shown) and black matrices (not shown) are generally formed on the upper substrate 80, but are not shown in order to simplify the drawings.

A liquid crystal material is injected between the upper substrate 80 and the lower substrate 10 to form the liquid crystal layer 100. At this time, the liquid crystal material is used having a negative refractive index anisotropy. In the state where no electric field is formed between the pixel electrode 50 and the counter electrode 90, the liquid crystal molecules are aligned to be perpendicular to the substrates 10 and 80.

Next, the driving principle of the liquid crystal display device having such a structure will be described.

As illustrated in FIG. 1C, when an electric field is formed between the pixel electrode 50 and the counter electrode 90, the vertically aligned liquid crystal molecules are rearranged in a direction perpendicular to the electric field line. At this time, the electric line of force spreads in a fan shape centering on the branch portions 51 and 52 of the pixel electrode 50 to reach the counter electrode 90. Therefore, the liquid crystal molecules are divided in two directions inclined between two adjacent branch portions 51. However, since the branch portions 51 and 52 include the vertical branch portion 51 and the horizontal branch portion 52, the tilting direction of the liquid crystal molecules is present in both up, down, left, and right directions. Therefore, a wide viewing angle can be secured in all four directions.

In the part where the tilt direction of the liquid crystal molecules is changed, that is, the part T2 equidistant from the upper part T1 of the branch parts 51 and 52 and two branch parts 51 and 52 adjacent to each other, the liquid crystal molecules are abnormally arranged. These parts T1 and T2 appear as a texture on the screen.

In the liquid crystal display device having such a structure, an opening pattern does not have to be formed on the counter electrode of the upper substrate, thereby simplifying the process and causing problems such as damage to the color filter or formation of an overcoat film. In addition, as will be described later, since the pixel electrodes are formed together with the same material as the data line, the thin film transistor substrate may be manufactured by only four photo etching processes.

Next, a method of manufacturing a liquid crystal display device having such a structure will be described.

First, a method of manufacturing the lower substrate will be described.

A gate including a gate line 20, a gate electrode 21, and a gate pad by depositing a gate metal such as chromium (Cr) or aluminum (Al) on the insulating substrate 10 and patterning the same through a first photolithography process. Form the wiring. Next, a gate layer 30 made of silicon nitride (SiNx) or the like, a semiconductor layer made of amorphous silicon, and a contact layer heavily doped with N-type impurities such as phosphorus (P) are sequentially deposited on the gate wiring. The contact layer pattern and the semiconductor layer 60 are formed by patterning the contact layer and the semiconductor layer through a second photolithography process. Next, the pixel electrode together with the data line including the data line 40, the source electrode 41, the drain electrode 42, and the data pad by depositing a data metal such as chromium or aluminum and patterning the same through a third photolithography process. To form (50). Subsequently, a protective film is formed by stacking an inorganic or organic insulating film and patterned through a fourth photolithography process to form contact holes for exposing the gate pad and the data pad.

Next, a method of manufacturing the upper substrate will be described.

A material such as chromium or a chromium oxide film is deposited on the substrate 80 and photo-etched to form a black matrix, and a color filter is formed using a printing method or the like. Next, a transparent conductive material such as ITO or IZO is deposited on the entire surface of the color filter to form a counter electrode.

The upper and lower substrates are aligned and attached, and a liquid crystal material is injected and sealed between the upper and lower substrates.

Next, a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 1B and 1C.

The second embodiment is almost similar in structure to the first embodiment. However, the shape of the pixel electrode 50 is different. The linear branches 51 and 52 of the pixel electrode 50 include a first branch 51 forming about 45 ° with respect to the data line 40 and a second branch 52 forming about 135 °. .

The driving principle and advantages of the liquid crystal display according to the second embodiment are the same as those of the first embodiment.

2A and 2B are layout views of the liquid crystal display according to the third and fourth embodiments of the present invention, respectively, and FIG. 2C is a cross-sectional view taken along line IIc-IIc ′ of FIGS. 2A and 2B.

The third embodiment of the present invention is the same as the first embodiment except for the common electrode wirings 25 and 26 formed on the lower substrate 10. The common electrode wires 25 and 26 include a common electrode line 25, a common electrode 27 and 28, and a connection portion 29 connecting the common electrodes 27 and 28. The common electrodes 27 and 28 include a vertical electrode 27 and a horizontal electrode 28. These vertical electrodes 27 and horizontal electrodes 28 are formed between the vertical branch portions 51 and the horizontal branch portions 52 of the pixel electrode 50, respectively. The common electrodes 27 and 28 are equidistant from two neighboring pixel electrode branches 51 and 52. The common electrode wirings 25 and 26 are formed in the same process step in the same layer as the gate wiring.

The liquid crystal display according to the fourth exemplary embodiment of the present invention is the same as the second exemplary embodiment except for the common electrode wirings 25 and 26 formed on the lower substrate 10. The common electrode wires 25 and 26 include a common electrode line 25, a common electrode 27 and 28, and a connection portion 29 connecting the common electrodes 27 and 28. The common electrodes 27 and 28 include a first common electrode 27 that forms an angle of about 45 ° with the data line 40, and a second common electrode 28 that forms an angle of about 135 ° with the data line 40. The common electrodes 27 and 28 are formed between the first branch portions 51 and the second branch portions 52 of the pixel electrode 50, respectively. The common electrodes 27 and 28 have the same spacing between two neighboring pixel electrode branches 51 and 52. The common electrode wirings 25 and 26 are formed in the same process step in the same layer as the gate wiring.

Next, the effect of further forming the common electrode wirings 25 and 26 will be described with reference to FIG. 2C.

As shown in FIG. 2C, an electric field is formed between the branch portion 51 of the pixel electrode and the common electrode 27. This electric field affects the entire electric field between the upper and lower substrates 10 and 80 to increase the horizontal component of the electric line of force. Thus, the fringe field is more surely formed. In addition, since the common electrodes 27 and 28 are positioned at the portion T2 where the texture is generated, the light may be blocked to block the texture, thereby improving image quality.

The fifth to eighth embodiments of the present invention will be described.

3A and 3B are layout views of a liquid crystal display device according to fifth and sixth embodiments of the present invention, respectively, and FIG. 3C is a cross-sectional view taken along line IIIc-IIIc 'of FIGS. 3A and 3B, and FIGS. 4A and 4B. Are layout views of the liquid crystal display according to the seventh and eighth embodiments of the present invention, and FIG. 4C is a cross-sectional view taken along line IVc-IVc 'of FIGS. 4A and 4B.

First, a liquid crystal display according to a fifth exemplary embodiment of the present invention will be described with reference to FIGS. 3A and 3C.

The gate line 20 extends in the horizontal direction on the lower insulating substrate 10, and the gate electrode 21 is formed in the form of a protrusion on the gate line 20.

The common electrode wiring including the common electrode 28, the common electrode connecting portion 29, and the common electrode lines 25, 26, and 27 is formed on the lower insulating substrate 10. The common electrode 28 is formed to form about 45 ° and −45 ° with respect to the gate line 20. The common electrode connecting portion 29 connects both ends of the common electrode 28, respectively. Three common electrode lines 25, 26, and 27 are formed in the horizontal direction, but the number thereof may increase or decrease.

The gate insulating film 30 is formed on the gate wirings 20 and 21 and the common electrode wirings 25, 26, 27, 28, and 29. A semiconductor pattern (not shown) that functions as a channel portion of the thin film transistor is formed on the gate insulating film 30 above the gate electrode 21. On the semiconductor pattern, contact layer patterns (not shown) which are separated on both sides are formed. At this time, the semiconductor pattern is made of amorphous silicon, and the contact layer pattern is made of amorphous silicon heavily doped with N-type impurities. In the present embodiment, the thin film transistor is formed using amorphous silicon, but may be formed using polycrystalline silicon.

The data line 40 extends in the vertical direction on the gate insulating film 30, and the source electrode 41 is formed on the data line 40 as a branch. The source electrode 41 extends over one contact layer pattern. A drain electrode 42 is formed on the other contact layer pattern, and the drain electrode 42 is connected to the pixel electrode 50.

The passivation film 70 is formed on the data wirings 40, 41, and 42. In the passivation layer 70, a contact hole 71 exposing the drain electrode 42 is formed.

The pixel electrode 50 made of a transparent conductive material such as ITO or IZO is formed on the passivation layer 70. First opening patterns 51 and 52 are formed in the pixel electrode 50. The first opening patterns 51 and 52 include horizontal openings 52 positioned in the upper and lower centers and diagonal openings 51 positioned in the upper and lower portions, respectively. The diagonal opening 51 overlaps the common electrode 28. At this time, the width of the diagonal opening 51 is wider than the width of the common electrode 28 so that the common electrode 28 completely enters between the diagonal openings 51. The pixel electrode 50 is connected to the drain electrode 42 through the contact hole 71.

The upper substrate 80 is formed with an opposite electrode 90 made of a transparent conductive material such as ITO or IZO. The second opening pattern 91 is formed on the counter electrode 90. The second opening pattern 91 is formed to be parallel to the diagonal opening 51 at a portion overlapping with the central portion of the pixel electrode 50, and to be parallel to the edge at a portion overlapping the edge of the pixel electrode 50. The second opening pattern 91 is sandwiched between the first opening patterns 51.

In addition to the counter electrode 90, a color filter (not shown) and a black matrix (not shown) are also formed on the upper substrate 80, but the drawings are omitted for simplicity.

A liquid crystal material is injected between the upper substrate 80 and the lower substrate 10 to form the liquid crystal layer 100. At this time, the liquid crystal material is used having a negative refractive index anisotropy. In the state where no electric field is formed between the pixel electrode 50 and the counter electrode 90, the liquid crystal molecules are aligned to be perpendicular to the substrates 10 and 80.

In the liquid crystal display having such a structure, the common electrode 28 is formed to overlap the first opening pattern 51, so that a necessary fringe field can be formed even if the width of the opening patterns 51 and 91 is narrower than in the related art. That is, as shown in FIG. 3C, an electric field is formed between the pixel electrode 50 and the common electrode 28, which also affects the electric field between the pixel electrode 50 and the counter electrode 90, thereby fringe field. To increase the horizontal component. Therefore, even if the width of the opening patterns 51 and 91 (especially the width of the first opening pattern 51) is reduced, it is possible to have a fringe field having a sufficient horizontal component. In this case, it is sufficient even if the width of the first opening pattern is formed between 5 μm and 7 μm. As the width of the opening patterns 51 and 91 decreases, the opening ratio increases.

Next, a liquid crystal display according to a sixth exemplary embodiment of the present invention will be described with reference to FIGS. 3B and 3C.

The sixth embodiment is the same as the fifth embodiment except for the planar shape of the first and second opening patterns 51, 91 and the common electrode wirings 25, 26, 27, 28, 29. In the sixth embodiment, the common electrode 28 is formed to be parallel to or perpendicular to the gate line 20. The first opening pattern 51 formed in the pixel electrode 50 overlaps with the common electrode 28. The width of the first opening pattern 51 is wider than the width of the common electrode 28. The second opening pattern 91 is also formed to be parallel to or perpendicular to the gate line 20, with the first opening pattern 51 interposed therebetween.

In the sixth embodiment, the same effects as in the fifth embodiment can be obtained by the common electrode 28.

Next, a seventh embodiment of the present invention will be described with reference to FIGS. 4A and 4C.

4A and 4C, the seventh embodiment is the same as the fifth embodiment except that the width of the common electrode 28 is wider than the first opening pattern 51. Even when the width of the common electrode 28 is wider than the first opening pattern 51, the horizontal component of the fringe field may be enhanced.

Next, an eighth embodiment of the present invention will be described with reference to FIGS. 4B and 4C.

4B and 4C, the eighth embodiment is the same as the sixth embodiment except that the width of the common electrode 28 is wider than the first opening pattern 51.

In the fifth to eighth embodiments, the width of the common electrode 28 may be formed to be 3 μm to 8 μm, and the width of the first opening pattern 51 may be formed to be 5 μm to 7 μm.

If the liquid crystal display device is manufactured as described above, the manufacturing process may be simplified and the defect may be reduced to reduce the cost and the aperture ratio may be improved.

Claims (20)

First insulating substrate, A gate line formed on the first substrate and formed in the first direction, A data line formed on the first substrate and insulated from and intersecting the gate line; A pixel electrode formed in an area where the two adjacent gate lines intersect the data line and including a plurality of linear branches and a stem connecting the linear branches; A switching element configured to transfer or block a signal of the data line to the pixel electrode according to the signal of the gate line; A second insulating substrate facing the first insulating substrate, Opposite electrode formed on the second insulating substrate Liquid crystal display comprising a. In claim 1, The branch part of the pixel electrode includes a first direction branch part and a second direction branch part different from the first direction. In claim 2, And an angle formed between the first direction and the second direction is 90 °. In claim 3, The first direction is a direction parallel to the data line. In claim 3, And the first direction forms 45 ° with the data line. In claim 1, And the pixel electrode is made of the same material on the same layer as the data line. In claim 6, And the pixel electrode is made of an opaque metal and the counter electrode is made of a transparent conductor. In claim 1, The switching element includes a gate electrode connected to the gate line, an amorphous silicon layer formed on the gate electrode, a source electrode formed on the amorphous silicon layer and connected to the data line, and the source electrode on the amorphous silicon layer. And a thin film transistor facing the pixel electrode and connected to the pixel electrode. In claim 1, A liquid crystal layer which is injected between the first insulating substrate and the second insulating substrate, and has a long axis direction of molecules arranged in a direction perpendicular to the first and second insulating substrates without an electric field applied thereto; A liquid crystal display device further comprising. The method according to any one of claims 1 to 9, And a common electrode connecting portion formed on the first insulating substrate and parallel to the branch portions of the pixel electrode and connecting the plurality of common electrodes to each other. In claim 10, And the common electrode and the common electrode connection part are formed of the same material on the same layer as the gate line. Forming a gate wiring on the insulating substrate, Stacking a gate insulating film, a semiconductor layer, and a contact layer on the gate wiring; Patterning the contact layer and the semiconductor layer to form a contact layer pattern and a semiconductor pattern, Forming a pixel electrode together with the data wiring, Etching the contact layer pattern to separate the source electrode contact layer and the drain electrode contact layer; Forming a protective film The manufacturing method of the board | substrate for liquid crystal display devices containing these. First insulating substrate, A gate line formed on the first substrate and formed in the first direction, A linear common electrode formed on the first substrate, A common electrode line connecting the common electrode, A data line formed on the first substrate and insulated from and intersecting the gate line; A pixel electrode formed in an area where two adjacent gate lines intersect the data line and having a first opening pattern; A liquid crystal display substrate comprising: a switching element configured to transfer or block a signal of the data line to the pixel electrode in response to a signal of the gate line; The common electrode overlaps the first opening pattern of the pixel electrode. In claim 13, And the common electrode is narrower in width than the first opening pattern. In claim 13, And the common electrode is wider than the first opening pattern. In claim 13, The first opening pattern may include a horizontal opening formed in a horizontal direction at a position that divides the pixel electrode up and down, and a diagonal opening formed in a diagonal direction in the upper and lower portions of the pixel electrode divided in half. The openings are perpendicular to each other, the substrate for a liquid crystal display device. In claim 13, And the first opening pattern includes a horizontal opening positioned on one side of the pixel electrode and parallel to the gate line, and a vertical opening positioned on the other side and parallel to the data line. The liquid crystal display substrate of Claim 13, A second substrate facing the substrate for the liquid crystal display device; And a counter electrode formed on the second substrate and having a second opening pattern. The method of claim 18, The first opening pattern may include a horizontal opening formed in a horizontal direction at a position that divides the pixel electrode up and down, and a diagonal opening formed in a diagonal direction in the upper and lower portions of the pixel electrode divided in half. The openings are perpendicular to each other, The second opening pattern includes an oblique portion parallel to the diagonal opening of the first opening pattern and a refraction portion overlapping the side of the pixel electrode. The method of claim 18, The first opening pattern includes a first horizontal opening positioned on one side of the pixel electrode and parallel to the gate line, and a first vertical opening positioned on the other side of the pixel electrode and parallel to the data line; The second opening pattern may include a second horizontal opening sandwiching the first horizontal opening, and a second vertical opening parallel to the first horizontal opening, and a second vertical opening parallel to the first horizontal opening.