CN108983511B

CN108983511B - Pixel structure and display panel

Info

Publication number: CN108983511B
Application number: CN201810896360.2A
Authority: CN
Inventors: 叶岩溪
Original assignee: TCL Huaxing Photoelectric Technology Co Ltd
Current assignee: TCL Huaxing Photoelectric Technology Co Ltd
Priority date: 2018-08-08
Filing date: 2018-08-08
Publication date: 2021-07-27
Anticipated expiration: 2038-08-08
Also published as: CN108983511A

Abstract

The invention provides a pixel structure, which comprises a pixel electrode and a common electrode, wherein the pixel electrode and the common electrode are arranged in different layers, the common electrode comprises a main body and a peripheral part wound on the main body, the main body and the pixel electrode are oppositely arranged, and a hollow area is formed in an area adjacent to the main body and the peripheral part. Because the main body of the public electrode and the adjacent area of the peripheral part form a hollow area, the lateral electric field can be strengthened when voltage is applied to the public electrode and the pixel electrode, and then the poor alignment property and the generation of dark stripes are reduced. The invention also provides a display panel.

Description

Pixel structure and display panel

Technical Field

The invention relates to the technical field of display, in particular to a pixel structure and a display panel.

Background

Active Thin Film Transistor liquid crystal displays (TFT-LCDs) have been rapidly developed and widely used in recent years. Among them, the Vertical Alignment (VA) type TFT-LCD display panel has a very wide application in large-sized displays such as televisions due to its extremely high contrast.

The HVA (High-Quality Vertical Alignment) technology is currently the VA technology used in large-size LCDs on the market. The HVA TFT-LCD display panel generally includes an upper substrate and a lower substrate, the upper substrate is a color filter substrate (CF substrate), the lower substrate is an Array substrate (Array substrate), and a liquid crystal layer is disposed between the two substrates.

As shown in fig. 1, a schematic diagram of a pixel structure 60 in a conventional HVA-type TFT-LCD display panel is shown. The pixel structure 60 includes a pixel electrode 61 and a common electrode 62. The pixel electrode 61 is disposed on the array substrate, and the common electrode 62 is disposed on the color filter substrate. The conventional HVA-type TFT-LCD display panel employs a technique of dividing each pixel electrode 61 into 4 pixel regions (domains). The pixel electrode 61 further includes a branch electrode 611 and a Slit (Slit)612 arranged at intervals.

Due to the existence of the slit 612, the liquid crystal molecules 63 have a weak tilt angle along the direction of the slit 612, as shown in fig. 2. After the LCD is formed into a cell, the liquid crystal molecules 63 are usually photo-aligned twice: alignment under voltage sequence and alignment under ultraviolet irradiation.

Referring to fig. 3 and 4, which are schematic diagrams illustrating alignment of the liquid crystal molecules 63 under a voltage sequence, it is difficult for the weak pretilt angle of the liquid crystal molecules 63 to rotate according to a specific angle under the vertical electric field 601, and at this time, the lateral electric fields 603 on the four sides of the pixel electrode 61 play a key role. The electric field lines of the lateral electric field 603 are not vertical, but have a certain inclination, so that they form a certain angle with the liquid crystal molecules 63, which corresponds to a large pretilt angle of the liquid crystal molecules 63. Under the action of the electric field force, the liquid crystal molecules 63 will rotate along the pre-tilt angle direction, and the liquid crystal molecules 63 will not reach the force equilibrium state (the electro-optical characteristic of negative liquid crystal) until they are perpendicular to the electric force lines. Due to the presence of the lateral electric field 603, the liquid crystal molecules 63 are continuously rotated and reach a predetermined target.

However, the lateral electric field 603 of the pixel structure 60 is a very weak electric field, and the pretilt angle of the liquid crystal molecules 63 is affected by the topography generated by other layers in the display panel besides being formed under the slit 612. for example, in the Black Photo Spacer (BPS) technology, on the gate (gate) line, due to the presence of the BPS, a very high topography is formed, which severely affects the pretilt angle direction of the liquid crystal branches, resulting in dark fringes.

Disclosure of Invention

In order to solve the foregoing problems, the present invention provides a pixel structure and a display panel.

A pixel structure comprises a pixel electrode and a common electrode which are arranged in different layers, wherein the common electrode comprises a main body and a peripheral part wound on the main body, the main body and the pixel electrode are arranged oppositely, and a hollow area is formed in an area adjacent to the main body and the peripheral part.

Furthermore, the pixel electrode comprises a frame, a first main electrode and a second main electrode, the frame surrounds the first main electrode and the second main electrode, and the hollow area is covered by the orthographic projection of the frame on the common electrode.

Furthermore, the hollow area comprises a first hollow part and a second hollow part connected with and communicated with the first hollow part, the frame comprises a first connecting part and a second connecting part connected with the first connecting part, the first hollow part corresponds to the first connecting part, and the second hollow part corresponds to the second connecting part.

Furthermore, the pixel electrode comprises a first main electrode and a second main electrode, the first main electrode and the second main electrode are arranged in a crossed mode, so that the pixel electrode forms four pixel areas, the number of the hollow areas is four, and each hollow area corresponds to one pixel area.

Furthermore, a plurality of branch electrodes arranged at intervals are arranged in the pixel area, a pixel electrode slit is formed between every two adjacent branch electrodes, the hollow-out area comprises a plurality of common electrode slits, and each common electrode slit is arranged corresponding to one pixel electrode slit.

Furthermore, a connecting tooth is formed between two adjacent common electrode slits, each connecting tooth corresponds to one branch electrode, and the orthographic projection of each connecting tooth on the pixel electrode is positioned on the branch electrode corresponding to the connecting tooth.

Further, the length of the common electrode slit is smaller than that of the pixel electrode slit corresponding to the common electrode slit.

Further, the pixel electrode slits in each pixel region are inclined at the same angle with respect to the horizontal direction.

Further, the pixel electrode further comprises liquid crystal molecules arranged between the pixel electrode and the common electrode.

A display panel comprising a plurality of pixel structures as described above.

According to the pixel structure and the display panel provided by the invention, the hollow-out area is formed in the area adjacent to the main body and the peripheral part of the common electrode, so that a lateral electric field around the pixel electrode can be enhanced when voltage is applied to the common electrode and the pixel electrode, and further the poor alignment property is reduced and the generation of dark fringes is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a pixel structure in the prior art;

FIG. 2 is a sectional view taken along line AA' in FIG. 1 in the presence of an electric field;

FIG. 3 is a sectional view taken along line AA' in FIG. 1 in the absence of an electric field;

FIG. 4 is a schematic diagram of a negative liquid crystal reaching a force equilibrium under the action of an electric field force;

FIG. 5 is a schematic diagram of a display panel according to an embodiment of the present invention;

FIG. 6 is a diagram illustrating a pixel structure according to an embodiment of the present invention;

FIG. 7 is a schematic view of a common electrode;

fig. 8 is a cross-sectional view of a state along the line BB' in fig. 6 in the presence of an electric field.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 5 is a schematic view of a display panel 200 according to an embodiment of the invention. The display panel 200 includes a plurality of pixel structures 100.

Fig. 6 is a schematic diagram of a pixel structure 100 according to an embodiment of the invention. The pixel structure 100 includes a pixel electrode 10 and a common electrode 30 disposed in different layers. In this embodiment, the pixel electrode 10 is disposed on the array substrate (not shown), and the common electrode 30 is disposed on the color filter substrate (not shown).

The pixel electrode 10 has a substantially rectangular shape. The pixel electrode 10 includes a first main electrode 12, a second main electrode 13, a frame 14 and a branch electrode 15. The first and second

main electrodes

12 and 13 are disposed to intersect with each other to partition the pixel electrode 10 into four pixel regions (domains) 16. In this embodiment, the first trunk electrode 12 and the second trunk electrode 13 intersect vertically, and the first trunk electrode 12 extends in the horizontal direction (lateral direction). The second trunk electrode 13 extends in a direction (longitudinal direction) perpendicular to the horizontal direction.

The frame 14 surrounds the first main electrode 12, the second main electrode 13 and the four pixel regions 16. The frame 14 includes a first connection portion 141 and a second connection portion 142 connected to the first connection portion 141. In other words, in the present embodiment, the first connection portion 141 and the first trunk electrode 12 are disposed in parallel at an interval, and the second trunk electrode 13 is perpendicularly connected to the first connection portion 141; the second connecting portion 142 and the second main electrode 13 are disposed in parallel at an interval, and the first main electrode 12 and the second connecting portion 142 are perpendicularly connected.

Each pixel region 16 is provided with a plurality of spaced parallel branch electrodes 15. The branch electrode 15 is disposed obliquely to the horizontal direction. The pixel electrode slit 17 is formed between the adjacent branch electrodes 15. Further, the pixel electrode slits 17 in each pixel region 16 are inclined at the same angle with respect to the horizontal direction. The branch electrodes 15 in each pixel region 16 are inclined at the same angle with respect to the horizontal direction.

The four pixel regions 16 include a first pixel region 163, a second pixel region 164, a third pixel region 165, and a fourth pixel region 166. In this embodiment, the branch electrode 15 in the first pixel region 163 is inclined at 45 degrees with respect to the first main electrode 12; the branch electrodes 15 in the second pixel region 164 are inclined by 135 degrees with respect to the first main electrode 12; the branch electrode 15 in the third pixel region 165 is tilted by-45 degrees with respect to the first main electrode 12; the branch electrode 15 in the fourth pixel region 166 is inclined at-135 degrees with respect to the first main electrode 12. It is to be understood that the inclination angle of the branch electrode 15 in each pixel region 16 is not limited to the example of the present embodiment, and the inclination angle may be 30 degrees, 50 degrees, or the like.

Referring to fig. 7, the common electrode 30 is substantially rectangular. The common electrode 30 has an area larger than that of the pixel electrode 10. The common electrode 30 includes a main body 31 and a peripheral portion 33. In the present embodiment, the area occupied by the main body 31 is substantially the same as the area occupied by the pixel electrode 10. The main body 31 is disposed opposite to the pixel electrode 10. Further, the main body 31 is covered by the orthographic projection of the pixel electrode 10 on the common electrode 30, and the overlapping area of the orthographic projection of the pixel electrode 10 on the common electrode 30 and the peripheral portion 33 is zero. The area of the body 31 adjacent the periphery 33 forms a hollowed-out area 35. The hollow area 35 is disposed corresponding to an edge of the pixel electrode 10. The hollow area 35 is used for weakening a vertical electric field between the common electrode 30 and the pixel electrode 10 and enhancing a lateral electric field formed by the common electrode 30 and the pixel electrode 10 when a voltage is applied to the common electrode 30 and the pixel electrode 10, so that an acting force of the lateral electric field on liquid crystal molecules is improved, alignment defect is reduced, and generation of dark fringes is reduced. In the present embodiment, the number of the hollow areas 35 is four, and each hollow area 35 is disposed corresponding to one pixel area 16.

Each of the hollow areas 35 includes a hollow portion 351 and a plurality of common electrode slits 352. The hollow portion 351 includes a first hollow portion 3511 and a second hollow portion 3512 connected and communicated with the first hollow portion 3511. The first hollow portion 3511 is disposed corresponding to the first connecting portion 141, and the second hollow portion 3512 is disposed corresponding to the second connecting portion 142. In other words, the orthographic projection of each first connecting portion 141 on the common electrode 30 covers the corresponding first hollow portion 3511, and the orthographic projection of each second connecting portion 142 on the common electrode 30 covers the corresponding second hollow portion 3512. In this embodiment, the first hollow portion 3511 and the second hollow portion 3512 in each hollow area 35 are vertically connected.

Each common electrode slit 352 is disposed corresponding to one pixel electrode slit 17. The common electrode slit 352 can increase the pretilt angle of the liquid crystal molecules, and reduce the probability of liquid crystal training disorder. One end of the common electrode slit 352 is connected to and communicated with the hollow portion 351. Connecting teeth 3515 are formed between two adjacent common electrode slits 3512, each connecting tooth 3515 corresponds to one branch electrode 15, and the orthographic projection of each connecting tooth 3515 on the pixel electrode 10 is positioned on the branch electrode 15 corresponding to the connecting tooth 3515. The length of each connecting tooth 3515 is smaller than the length of the corresponding branch electrode 15. The length of the common electrode slit 352 is smaller than the length of the pixel electrode slit 17 corresponding to the common electrode slit 352. The first connecting bridge 361 is disposed between two adjacent first hollow portions 3511, and the second connecting bridge 363 is disposed between two adjacent second hollow portions 3512, so as to realize the connection of signals on the common electrode 30.

The four hollow areas 35 include a first hollow area 353, a second hollow area 354, a first hollow area 354 and a first hollow area 356. The first hollow portion 3511 of the first hollow region 353 is disposed adjacent to the first connection portion 141 of the first pixel region 163, and the second hollow portion 3512 of the first hollow region 353 is disposed corresponding to the second connection portion 142 of the first pixel region 163; the first hollow portion 3511 of the second hollow region 354 corresponds to the first connecting portion 141 adjacent to the second pixel region 164, and the second hollow portion 3512 of the second hollow region 354 corresponds to the second connecting portion 142 adjacent to the second pixel region 164; the first hollow portion 3511 of the third hollow area 355 is disposed corresponding to the first connection portion 141 adjacent to the first pixel area 163, and the second hollow portion 3512 of the third hollow area 355 is disposed corresponding to the second connection portion 142 adjacent to the third pixel area 165; the first hollow portion 3511 of the fourth hollow region 356 corresponds to the first connection portion 141 of the fourth pixel region 166, and the second hollow portion 3512 of the fourth hollow region 356 corresponds to the second connection portion 142 adjacent to the fourth pixel region 163.

The common electrode slits 352 of the first hollow-out region 353 are inclined by 45 degrees relative to the horizontal direction, the common electrode slits 352 of the second hollow-out region 354 are inclined by 135 degrees relative to the horizontal direction, the common electrode slits 352 of the third hollow-out region 355 are inclined by-45 degrees relative to the horizontal direction, and the common electrode slits 352 of the fourth hollow-out region 356 are inclined by-135 degrees relative to the horizontal direction.

Referring to fig. 8, each pixel structure 100 further includes liquid crystal molecules 50 (fig. 7 only shows some liquid crystal molecules 50) distributed between the common electrode 30 and the pixel electrode 10. When a voltage is applied to the common electrode 30 and the pixel electrode 10, the main body 31 of the common electrode 30 is opposite to the pixel electrode 10 except for the hollow area 53, and can form a vertical electric field, and the peripheral portion 33 of the common electrode 30 and the pixel electrode 10 form a lateral electric field. Since the edge region of the main body 31 adjacent to the peripheral portion 33 is the hollow region 35, a vertical electric field cannot be formed, and the field energy of the lateral electric field can be effectively increased according to the conservation of the field energy, that is, the influence of the lateral electric field on the liquid crystal molecules 50 can be enhanced.

According to the pixel structure 100 and the display panel 200 provided by the invention, the hollow-out region 35 is formed in the region of the main body 31 of the common electrode 30 adjacent to the peripheral portion 33, so that the lateral electric field can be enhanced, and the alignment defect and the generation of dark fringes can be reduced. Since the lateral electric field is intensified, even in a place where the topography is high, the influence of the display panel topography on the pretilt angle of the liquid crystal molecules 50 can be weakened. In addition, the common electrode 30 forms a common electrode slit 352 corresponding to the pixel electrode slit 17 of the pixel electrode 10, and since the common electrode 30 and the pixel electrode 10 are both slit designed, the pretilt angle of the original weak liquid crystal molecules 50 can be greatly enhanced, the probability of liquid crystal training disorder is greatly reduced, and the generation of dark fringes is also effectively avoided.

In order to enable the liquid crystal alignment to proceed as desired, a certain new design is made for the common electrode (CF ITO) on the color filter substrate. In the training of liquid crystal, the state of the boundary of the pixel electrode (Array ITO) on the Array substrate side is most important, and therefore, the new CF ITO is designed at the position corresponding to the edge region of the Array ITO. The second point is that the part of the junction area of the vertical electric field and the lateral electric field on the common electrode is removed to form a hollow area, so that the vertical electric field cannot be formed, the normal energy of the lateral electric field can be effectively increased according to the conservation of field energy, and the removed CF ITO just forms four hollow areas. The second point is that CF ITO is designed into corresponding public electrode slit in the area of the pixel electrode slit of the original Array ITO. Both Array ITO and CF ITO are designed into slits, so that the original weak pretilt angle of liquid crystal can be greatly enhanced, and the probability of liquid crystal training disorder is greatly reduced. The pixel structure and the display panel provided by the invention can effectively improve dark stripes caused by alignment.

In an embodiment, the frame 14 of the pixel electrode 10 may be omitted, and the hollow area 35 is disposed corresponding to an edge of the pixel area 16.

In one embodiment, the common electrode slit 352 of the common electrode 30 may be omitted, and the hollow region 35 includes the first hollow portion 3511 and/or the second hollow portion 3512.

In one embodiment, the frame 14 of the pixel electrode 10 may be omitted, and the hollow portion 351 of the hollow area 35 is omitted.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. A pixel structure is characterized by comprising a pixel electrode, a common electrode and liquid crystal molecules, wherein the pixel electrode and the common electrode are arranged in a different layer mode, the liquid crystal molecules are located between the pixel electrode and the common electrode, the common electrode comprises a main body and a peripheral portion arranged around the main body, the main body and the pixel electrode are arranged oppositely, a hollow-out area is formed in an area, adjacent to the peripheral portion, of the main body, the hollow-out area corresponds to the edge of the pixel electrode, and the overlapping area of the orthographic projection of the pixel electrode on the common electrode and the peripheral portion is zero.

2. The pixel structure according to claim 1, wherein the pixel electrode comprises a frame, a first main electrode and a second main electrode, the frame surrounds the first main electrode and the second main electrode, and an orthographic projection of the frame on the common electrode covers the hollow area.

3. The pixel structure according to claim 2, wherein the hollow area includes a first hollow portion and a second hollow portion connected to and communicating with the first hollow portion, the frame includes a first connecting portion and a second connecting portion connected to the first connecting portion, the first hollow portion is disposed corresponding to the first connecting portion, and the second hollow portion is disposed corresponding to the second connecting portion.

4. The pixel structure according to claim 1, wherein the pixel electrode includes a first main electrode and a second main electrode, the first main electrode and the second main electrode are disposed in a crossing manner, so that the pixel electrode forms four pixel regions, the number of the hollow regions is four, and each hollow region is disposed corresponding to one pixel region.

5. The pixel structure according to claim 4, wherein a plurality of branch electrodes are disposed at intervals in the pixel region, a pixel electrode slit is formed between two adjacent branch electrodes, and the hollow region includes a plurality of common electrode slits, each common electrode slit corresponding to one pixel electrode slit.

6. The pixel structure according to claim 5, wherein a connection tooth is formed between two adjacent common electrode slits, each connection tooth corresponds to one branch electrode, and an orthogonal projection of each connection tooth on the pixel electrode is located on the branch electrode corresponding to the connection tooth.

7. The pixel structure of claim 5, wherein a length of the common electrode slit is less than a length of a pixel electrode slit corresponding to the common electrode slit.

8. The pixel structure of claim 5, wherein the pixel electrode slits in each pixel region are inclined at the same angle with respect to the horizontal direction.

9. The pixel structure of claim 1, wherein the pixel electrode further comprises liquid crystal molecules disposed between the pixel electrode and the common electrode.

10. A display panel comprising a plurality of pixel structures according to any one of claims 1 to 9.