JP2000147509A - Structure for liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a structure for a liquid crystal panel which prevents light leakage defect by reducing reverse tilt around transistors. SOLUTION: When a direction from a thin film transistor substrate toward a liquid crystal layer is selected out of two directions of directors of a liquid crystal in a unit element, a transistor 11 is arranged in such a way that a projection of the direction on the substrate is directed to the transistor 11, and structures of a gate bus line 12 of the transistor 11 and pixel electrodes 14, 15 in its vicinity are designed in such a way that the bus line and the electrodes are arranged perpendicular with respect to a rubbing direction. All the liquid crystal molecules in the vicinity of the transistor have their pretilt in the same direction thereby. Furthermore, a structure in which either the bus line or an oblique wiring part of the electrode is not parallel with respect to the rubbing direction, or another structure in which a region of the second pixel electrode 15 freely overlaps with the first pixel electrode 14 or the other structure having both of the structures are possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel structure.

[0002]

2. Description of the Related Art FIG. 11 is a plan view of one pixel of a conventional liquid crystal display panel structure, and FIG. 12 is a line H of FIG.
FIG. 13 is a plan view of one pixel of another conventional example.

As shown in FIG. 1, a liquid crystal display panel includes a transistor 211 for driving liquid crystal, a gate bus line 212 for supplying a selection signal to the transistor,
It comprises a data bus line 213 for supplying display data to the transistor, and first and second pixel electrodes 214 and 215. The liquid crystal cell is formed of a counter substrate on which a conductive transparent electrode film for holding a liquid crystal layer is disposed between the substrate and a thin film transistor (TFT) substrate.

In operation, the transistor 211 is switched by the electric charge flowing through the gate bus line 212, and the electric charge information of the data bus line 213 is stored in the pixel electrode 11.
By writing and holding the data in No. 4, the liquid crystal between the liquid crystal and the opposing substrate rises further upward than the pretilt direction and enters a light transmitting state.

Here, attention is paid to liquid crystal molecules such as a transistor and pixel electrode boundary region HH 'in the drawing. FIG. 12 shows a cross-sectional view of this part. It is composed of a gate bus line 212, a pixel electrode 214, an insulating film 216, and an alignment film 217. Liquid crystal molecules 218 are arranged at a pretilt angle θ on the alignment film 217. Here, attention is paid to the boundary between the pixel electrode 214 and the gate bus line 212. Liquid crystal molecule 2
Numerals 18 follow the rubbing direction R and are uniformly arranged in the direction shown in the figure. However, the electric field applied between the gate bus line 212 and the pixel electrode 214 causes the liquid crystal molecules 218
Has a lower tilt and has a tilt in the opposite direction. This state is called reverse tilt.

The pixel electrode 214 is connected to the liquid crystal cell in this state.
When the liquid crystal molecules 218 are made to stand by applying an electric field between the liquid crystal and the counter electrode, the liquid crystal in the reverse tilt portion once becomes parallel to the substrate and then rises in the same direction as the liquid crystal in the normal portion. The boundary between the normal part and the reverse tilt part is a domain. Since the domain portion does not perform a normal display, the time when the liquid crystal in the reverse tilt portion rises in the same direction as the normal portion becomes an afterimage and causes display failure.

Further, it is known that in the transistor arrangement as shown in FIG. 12, a region where a domain occurs extends into the inside of the display region.

FIG. 13 is a plan view of one pixel of another conventional example.

FIG. 13 shows the shape of the reverse tilt. In this example, a driving transistor 221 and a gate bus line 22 for supplying a selection signal to this transistor are described.
2. Data bus line 223 for supplying display data to transistors, and pixel electrodes 224 and 225. By driving, a reverse tilt domain 226 is generated as shown in the figure.

As a countermeasure against a display failure due to this phenomenon, it is already known that a portion where reverse tilt occurs is made outside the display region by a light-shielding region of the opposing substrate. In addition, Japanese Unexamined Patent Publication
It is already known that a portion corresponding to the back side in the rubbing direction is formed to have a shape in which the thickness is gradually reduced as shown by -134620 to suppress the reverse tilt. This method can be expected to reduce the overall reverse tilt, but is less effective in generating a shape-specific reverse tilt around the transistor.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film transistor (TFT) substrate in each pixel constituting a thin film transistor liquid crystal panel device (TFT-LCD) in order to solve the above-mentioned disadvantages of the prior art. The reverse tilt around the transistor is reduced by placing the transistor in the lower direction of Rabink and patterning the space between the transistor, gate and pixel electrode perpendicular to the rubbing direction, thereby preventing light leakage failure To provide a liquid crystal panel structure.

[0012]

According to the liquid crystal display panel structure of the present invention, when a direction from a thin film transistor substrate to a liquid crystal layer is selected from two directions of a liquid crystal director direction in a unit element, the direction is selected. The transistors are arranged such that the direction of projection onto the thin film transistor substrate is directed to the transistors, and the gate bus lines and the pixel electrodes are arranged such that the gate bus lines of the transistors and the pixel electrodes in the vicinity thereof are perpendicular to the rubbing direction. It is characterized by being arranged.

In the liquid crystal display panel structure, one of the gate bus line and the oblique wiring portion of the pixel electrode has a structure that is not parallel to the rubbing direction, or the region of the second pixel electrode is the first pixel electrode. It is preferable that the pixel electrode has a freely overlapping structure with respect to the pixel electrode, or has both structures.

According to a fifth aspect of the present invention, there is provided a liquid crystal display panel comprising:
When the direction from the thin film transistor substrate to the liquid crystal layer is selected from the two directions of the liquid crystal director direction in the unit element, the transistor is arranged so that the projection direction of the direction to the thin film transistor substrate is directed to the transistor. Is formed in a polygonal or elliptical shape so as to hide the shape of the reverse tilt domain.

In the liquid crystal display panel structure, the oblique wiring portion of the electrode has a structure in which one is not parallel to the other, or the region of the second pixel electrode is in the first region.
It is preferable that the pixel electrode has a freely overlapping structure with respect to the pixel electrode, or has both structures.

According to a ninth aspect of the present invention, there is provided a liquid crystal display panel comprising:
When the direction from the thin film transistor substrate to the liquid crystal layer is selected from the two directions of the liquid crystal director direction in the unit element, the transistor is arranged so that the projection direction of the direction to the thin film transistor substrate is directed to the transistor. It is characterized in that the structure of the gate bus line of the transistor and the pixel electrode in the vicinity thereof has an arbitrary angle so as to hide the reverse tilt domain.

The liquid crystal display panel further has a structure in which a gate bus line and a diagonal wiring portion of a pixel electrode are not parallel, or a region of a second pixel electrode is free with respect to a first pixel electrode. Those having an overlapping structure or those having both structures are preferred.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

In this description, the first to twelfth
The embodiment examples correspond to claims 1 to 12, respectively.

FIG. 1 is a plan view of one pixel of an embodiment of the liquid crystal display panel structure of the present invention, and FIG. 2 is a line A of FIG.
It is -A 'sectional drawing.

Referring to FIG. 1, the pixel of this embodiment includes a transistor 11 for driving liquid crystal, a gate bus line 12 for supplying a selection signal to the transistor,
It comprises a data bus line 13 for supplying display data to the transistors and pixel electrodes 14 and 15. The pixel electrode is composed of a first pixel electrode 14 which is a transparent electrode such as indium tin oxide (ITO) and an opaque second pixel electrode 15 such as Cr.
The two electrodes 14 and 15 are electrically connected. The liquid crystal cell includes a thin film transistor (TFT) substrate and an opposing substrate that is disposed to oppose the liquid crystal layer.

The position of each component is determined as follows. The transistor 11 is arranged such that when a direction from the TFT substrate to the liquid crystal layer is selected from two directions of the liquid crystal director direction in the unit element, the direction projected on the TFT substrate is directed to the transistor 11.

Gate bus line 12 and pixel electrode 14
Are arranged such that the longitudinal direction of the interval between the gate bus line 12 of the transistor 11 and the pixel electrode 14 is perpendicular to the director direction.

Here, an alignment film for regulating the alignment direction of the liquid crystal molecules 18 is applied to the surfaces of the TFT substrate and the counter substrate. Then, the orientation direction is determined by rubbing. The orientation direction is the direction of arrow R in the figure.
This angle is about 45 degrees with respect to the direction of the element. The liquid crystal molecules 18 are tilted with respect to the rubbing direction, slightly upward in the front and downward in the rear. This is called pretilt.

In the present invention, the occurrence of reverse tilt in which the pretilt is reversed by the electric field is suppressed.

Next, the operation of this embodiment will be described.

The operation of driving the liquid crystal in the structure of FIG. 1 is the same as the conventional method. That is, the transistor 11 is switched by the charge flowing through the gate bus line 12, and the charge information of the data bus line 13 is written to the pixel electrode 14 and held. By this operation, the liquid crystal between the liquid crystal and the opposing substrate rises further upward than the pretilt direction, and enters a light transmitting state. By utilizing this, display is performed by controlling the voltage of the data bus line 13.

Referring to FIG. 2, which shows a cross-sectional view of the region AA ′ of FIG. 1, the gate bus line 12 and the pixel electrode 14
And an insulating film 16 and an orientation film 17. Alignment film 1
On 7, liquid crystal molecules 18 are arranged at a pretilt angle θ.
Here, attention is paid to the liquid crystal molecules 18. The liquid crystal molecules 18 are uniformly arranged in the direction shown in the figure according to the rubbing direction R (= A → A ′). Gate bus line 12 and pixel electrode 14
Is applied in the same direction as the direction in which the liquid crystals are arranged. By applying an electric field between the pixel electrode 14 and the counter electrode, all the liquid crystal molecules 18 rise vertically to the alignment film 17. Next, a second embodiment will be described.

FIG. 3 is a plan view of one pixel of the second embodiment.

In the first embodiment, one of the gate bus line and the oblique wiring portion of the pixel electrode may not be parallel to the rubbing direction. The present embodiment is a case where only the first pixel electrodes 24 are arranged perpendicular to the rubbing angle. The difference from the first embodiment is that the first pixel electrode 24 is arranged perpendicular to the rubbing angle in the region B26. On the other hand, the gate bus line 23 is not perpendicular to the rubbing angle. in this case,
The distance between the end of the gate bus line 23 and the transistor 21 can be increased, and the degree of freedom in transistor design can be increased.

Next, a third embodiment will be described.

FIG. 4 is a plan view of one pixel of the third embodiment.

In the first embodiment, the area of the second pixel electrode may be freely set. In this embodiment,
This is a case where the second pixel electrode 35 is extended to the oblique area of the first pixel electrode 34. The difference from the first embodiment is that the second pixel electrode 35 in the region C
One portion extends to the oblique area of the first pixel electrode 34.

As an effect, the larger the contact area between the first pixel electrode 34 and the second pixel electrode 35, the lower the contact resistance.

Next, a fourth embodiment will be described.

This embodiment is not shown. In the second embodiment, similarly to the third embodiment, the area of the second pixel electrode may be set freely. For example, the second pixel electrode may extend from the transistor portion to the first pixel electrode diagonal region. In the third embodiment, one of the gate bus line and the oblique wiring portion of the pixel electrode is not parallel to the rubbing direction as in the second embodiment.

Next, a fifth embodiment will be described.

FIG. 5 is a plan view of one pixel of the fifth embodiment.

In the first embodiment, the same effect can be obtained even if the gate bus lines and the oblique wiring portions of the pixel electrodes are polygonal or elliptical in accordance with the shape of the reverse tilt domain. For example, a structure as shown in FIG. 5 can be considered. As in FIG. 1, a transistor 51 for driving liquid crystal is provided in the pixel, and the transistor 51
And a data bus line 53 for supplying display data to the transistors, and first and second pixel electrodes 54 and 55. The gate bus line 52 above the transistor 51 is
It is divided into a portion KA having an angle different from the rubbing angle and a portion KB perpendicular to the rubbing angle.

The operation is the same as in the first embodiment. The reverse tilt domain 56 generated on the data bus line 53 is connected to the transistor 5 from the data bus line 53.
1 occurs as shown in the figure. The gate bus line 51 has a shape such that the reverse domain 56 does not appear in the display area.

In this case, the opening is wider than in the first embodiment, which is more effective.

Next, a sixth embodiment will be described.

FIG. 6 is a plan view of one pixel of the sixth embodiment.

In the fifth embodiment, one of the oblique wiring portions of the pixel electrode may not be parallel to the other. This embodiment is shown in FIG. The difference from the fifth embodiment is that in the region D, the method of chamfering the pixel electrode 64 and the method of chamfering the gate bus line 62 are different. In FIG. 6, both the pixel electrode 64 side and the gate bus line 62 side are constituted by the same two sides, but they are not particularly arranged in parallel. The degree of freedom in design is greater than in the fifth embodiment.

Next, a seventh embodiment will be described.

FIG. 7 is a plan view of one pixel of the seventh embodiment.

In the fifth embodiment, the area of the second pixel electrode may be freely set. The example of FIG. 7 is a case where the second pixel electrode 75 is extended to the oblique area of the first pixel electrode 74. The second pixel electrode 75 extends from the transistor 71 to an oblique region of the first pixel electrode 74.

As an effect, the larger the contact area between the first pixel electrode 74 and the second pixel electrode 75, the lower the contact resistance.

Next, an eighth embodiment will be described.

This embodiment is not shown. In the sixth embodiment, the area of the second pixel electrode is freely set as in the seventh embodiment.

In the seventh embodiment, as in the sixth embodiment, one of the oblique wiring portions of the pixel electrode may not be parallel to the other.

Next, a ninth embodiment will be described.

FIG. 8 is a plan view of one pixel of the ninth embodiment.

In the first embodiment, the gate bus lines and the oblique wiring portions of the pixel electrodes may be changed to any angle in accordance with the shape of the reverse tilt domain. An example is a structure as shown in FIG. 8 of the embodiment.

As in FIG. 1, the pixel includes a transistor 91 for driving liquid crystal, a gate bus line 92 for supplying a selection signal to the transistor 91, and a transistor 9
1 comprises a data bus line 93 for supplying display data and first and second pixel electrodes 84 and 85. Gate bus line 92 above transistor 91
Has an angle such that the reverse tilt domain 96 generated on the data bus line 93 does not enter the display area.

Next, a tenth embodiment will be described.

FIG. 9 is a plan view of one pixel of the tenth embodiment.

In the ninth embodiment, the gate bus lines and the oblique wiring portions of the pixel electrodes need not be parallel. This is the tenth embodiment. The difference from the ninth embodiment is that the first pixel electrode 10
4 and the gate bus line 102 electrode are not parallel. In this case, the distance between the end of the gate bus line 102 and the transistor 101 can be increased, and the degree of freedom in transistor design can be increased.

Next, an eleventh embodiment will be described.

FIG. 10 is a plan view of one pixel of the eleventh embodiment.

In the ninth embodiment, the area of the second pixel electrode may be freely set. This is the case where the second pixel electrode 115 is extended to the oblique area of the first pixel electrode 114 in the present embodiment. In the region G117, the second pixel electrode 115 extends from the portion of the transistor 111 to the oblique region of the first pixel electrode 114. As an effect, the larger the contact area between the first pixel electrode 114 and the second pixel electrode 115, the lower the contact resistance.

Finally, a twelfth embodiment will be described.

This embodiment is not shown. In the tenth embodiment, the area of the second pixel electrode may be freely set as in the eleventh embodiment. Conversely, in the eleventh embodiment, the gate bus line and the oblique wiring portion of the pixel electrode need not be parallel.

[0064]

As described above, according to the present invention, in the liquid crystal display panel structure, when the direction from the thin film transistor substrate to the liquid crystal layer is selected from the two directions of the liquid crystal director direction in the unit element, the direction of the direction is selected. The transistors are arranged such that the direction of projection onto the thin film transistor substrate is directed to the transistors, and the gate bus lines and the pixel electrodes are arranged such that the structure of the gate bus lines of the transistors and the pixel electrodes in the vicinity thereof are perpendicular to the rubbing direction. With this structure, all the liquid crystal molecules around the transistor have pretilt in the same direction, so that the occurrence of reverse tilt when an electric field is applied is reduced, and as a result, the afterimage is improved. It is effective, and the part where reverse tilt occurs is hidden by the light shielding part on the counter substrate side. Can remove stomach region, there is an effect of providing a liquid crystal display panel structure wide aperture ratio can be expected.

[Brief description of the drawings]

FIG. 1 is a plan view of one pixel of an embodiment of a liquid crystal display panel structure according to the present invention.

FIG. 2 is a sectional view taken along line A-A 'of FIG.

FIG. 3 is a plan view of one pixel according to a second embodiment.

FIG. 4 is a plan view of one pixel of a third embodiment.

FIG. 5 is a plan view of one pixel according to a fifth embodiment;

FIG. 6 is a plan view of one pixel according to a sixth embodiment;

FIG. 7 is a plan view of one pixel according to a seventh embodiment;

FIG. 8 is a plan view of one pixel according to a ninth embodiment.

FIG. 9 is a plan view of one pixel of the tenth embodiment.

FIG. 10 is a plan view of one pixel of the eleventh embodiment.

FIG. 11 is a plan view of one pixel of one conventional liquid crystal display panel structure.

FIG. 12 is a sectional view taken along line H-H ′ of FIG. 11;

FIG. 13 is a plan view of one pixel of another conventional example.

[Explanation of symbols]

11, 21, 31, 51, 61, 71, 91, 101,
111, 211, 221 Transistors 12, 22, 32, 52, 62, 72, 92, 102,
112, 212, 222 Gate bus lines 13, 23, 33, 53, 63, 73, 93, 103,
113, 213, 223 Data bus lines 14, 24, 34, 54, 64, 74, 94, 104,
114, 214, 224 first pixel electrode 15, 25, 35, 55, 65, 75, 95, 105,
115, 215, 225 Second pixel electrode 16, 216 Insulating film 17, 217 Alignment film 18, 218 Liquid crystal molecule 19, 219 Electric field direction 20 Area A 26 Area B 36 Area C 56, 66, 76, 96, 106, 116 , 226
Reverse tilt domain 67 Region D 77 Region E 107 Region F 117 Region G 220 Region HR Rubbing direction KA, KA'KC Part different from rubbing angle KB, KB 'Part perpendicular to rubbing angle θ Tilt angle

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H090 HD14 JB02 JD13 KA05 LA04 MA04 MA07 MA10 MB01 2H092 JA26 JA29 JA38 JA42 JA47 JB13 JB23 JB32 JB38 JB57 KA05 KA07 KA16 KA18 KB14 NA04 NA26 NA27 PA02 PA06 QA07 5A09 BA03A04 DA13 DB04 EA04 EA07 FA01 FB12

Claims (12)

[Claims] In a liquid crystal display panel structure, when a direction from a thin film transistor substrate to a liquid crystal layer is selected from two directions of a liquid crystal director direction in a unit element, a projection direction of the direction to the thin film transistor substrate is applied to the transistor. A liquid crystal, wherein a transistor is disposed so as to face the gate bus line and the pixel electrode such that a structure of the gate bus line of the transistor and a pixel electrode near the transistor are perpendicular to a rubbing direction. Display panel structure. 2. The liquid crystal display panel structure according to claim 1, wherein one of the gate bus line and the oblique wiring portion of the pixel electrode has a structure that is not parallel to the rubbing direction. 3. The liquid crystal display panel structure according to claim 1, wherein a region of the second pixel electrode has a structure freely overlapping the first pixel electrode. 4. The liquid crystal display panel structure according to claim 2, wherein a region of the second pixel electrode has a structure that freely overlaps with the first pixel electrode. 5. In a liquid crystal display panel structure, when a direction from a thin film transistor substrate to a liquid crystal layer is selected from two directions of a liquid crystal director direction in a unit element, a projection direction of the direction to the thin film transistor substrate is applied to the transistor. The transistor is arranged so as to face, and the structure of the gate bus line of the transistor and the pixel electrode in the vicinity thereof is formed in a polygonal or elliptical shape so as to hide the shape of the reverse tilt domain. LCD panel structure. 6. The liquid crystal display panel structure according to claim 5, wherein one of the oblique wiring portions of the electrode has a structure not parallel to the other. 7. The liquid crystal display panel structure according to claim 5, wherein a region of the second pixel electrode has a structure freely overlapping the first pixel electrode. 8. The liquid crystal display panel structure according to claim 6, wherein a region of the second pixel electrode has a structure freely overlapping the first pixel electrode. 9. In a liquid crystal display panel structure, when a direction from a thin film transistor substrate to a liquid crystal layer is selected from two directions of a liquid crystal director direction in a unit element, a projection direction of the direction to the thin film transistor substrate is applied to the transistor. A structure of a liquid crystal display panel, wherein a transistor is arranged so as to face, and an arbitrary angle is set so that a structure of a gate bus line of the transistor and a pixel electrode in the vicinity thereof hides a reverse tilt domain. 10. The liquid crystal display panel structure according to claim 9, wherein the gate bus lines and the oblique wiring portions of the pixel electrodes are not parallel. 11. The area of the second pixel electrode is free to the first pixel electrode.
10. The pixel electrode has a freely overlapping structure with respect to the pixel electrode.
Liquid crystal display panel structure as described. 12. The region of the second pixel electrode is free to the first pixel electrode.
2. The pixel electrode having a freely overlapping structure with respect to a pixel electrode.
0 liquid crystal display panel structure.