CN109326632B

CN109326632B - Display panel and display device

Info

Publication number: CN109326632B
Application number: CN201811158208.0A
Authority: CN
Inventors: 王刚; 李威龙; 张露; 韩珍珍; 胡思明
Original assignee: Kunshan Govisionox Optoelectronics Co Ltd
Current assignee: Kunshan Govisionox Optoelectronics Co Ltd
Priority date: 2018-09-30
Filing date: 2018-09-30
Publication date: 2020-12-04
Anticipated expiration: 2038-09-30
Also published as: CN109326632A

Abstract

The application provides a display panel and a display device, comprising a flexible substrate, a plurality of thin film transistors, a plurality of sub-pixel units and a plurality of signal transmission channels, wherein the plurality of thin film transistors are formed on the flexible substrate, and each thin film transistor comprises a signal end; each sub-pixel unit comprises a first electrode, and each sub-pixel unit is formed on a thin film transistor; each signal transmission channel comprises a first channel and a second channel which are respectively and electrically connected with the same first electrode, and the first channel and the second channel are respectively and electrically connected with the same signal end. Through setting up two at least passageways in this application for: even if the first electrode is broken due to bending, the broken area of the first electrode can still be connected with the signal end through at least two channels, so that the service life of the display panel is prolonged while the light-emitting area is ensured.

Description

Display panel and display device

Technical Field

The application relates to the field of display, in particular to a display panel and a display device.

Background

An organic light emitting display apparatus is a self-light emitting device using a thin emission layer between electrodes, and thus the entire device can be made thinner. In addition, the organic light emitting display device has advantages not only in power consumption of low voltage driving but also in color realization, response speed, viewing angle, and contrast.

And a flexible organic display device, which is manufactured to form a display unit and a conductive line on a substrate, which exhibits flexibility, such as a flexible material (e.g., plastic), thereby displaying an image even when bent like paper, receives a great deal of attention as a next-generation display device. Taking a flexible organic light emitting display device as an example, when the display device is bent, some film layers may be broken due to stress, causing partial failure, resulting in reduction of display area or poor display effect.

Disclosure of Invention

The application provides a flexible display panel and a display device with long service life.

The application provides a display panel, which comprises a flexible substrate, a plurality of thin film transistors, a plurality of sub-pixel units and a plurality of signal transmission channels, wherein the plurality of thin film transistors are formed on the flexible substrate, and each thin film transistor comprises a signal terminal; each sub-pixel unit comprises a first electrode, and each sub-pixel unit is formed on a thin film transistor; each signal transmission channel comprises a first channel and a second channel which are respectively and electrically connected with the same first electrode, and the first channel and the second channel are respectively and electrically connected with the same signal end.

Further, the first channel is connected to a first end of the first electrode, the second channel is connected to a second end of the first electrode, and the first end and the second end are arranged along the first direction.

Further, the first channel is connected to the second channel and electrically connected to the second end through the second channel.

Further, the first channel and the second channel are electrically connected in parallel.

Further, the ratio of the area of the signal transmission channel to the area of each sub-pixel unit ranges from 0.6% to 12%.

Further, the width range of the bypass part is 2-10 um.

Furthermore, each signal transmission channel comprises a third channel, the first channel, the second channel and the third channel are respectively and electrically connected with the same first electrode and the same signal end, the third channel is connected with the third end of the first electrode, the second end and the third end are arranged along the second direction, and an included angle is formed between the first direction and the second direction.

Further, the first direction is perpendicular to the second direction.

Furthermore, each signal transmission channel comprises a fourth channel, the first channel, the second channel, the third channel and the fourth channel are respectively and electrically connected with the same first electrode and the same signal end, the fourth channel is connected with the fourth end of the first electrode, and the third end and the fourth end are arranged along the first direction.

The present application also provides a display device including the display panel.

Through setting up a plurality of passageways in this application, even if first electrode when because of bending fracture, the fracture area of first electrode still can be connected with the signal end through two at least passageways, has improved display panel's life when guaranteeing light-emitting area.

Drawings

FIG. 1 is a schematic cross-sectional view of one embodiment of a display panel of the present application;

FIG. 2 is a schematic top view of a first electrode and a signal transmission channel of the display panel shown in FIG. 1;

FIG. 3 is a schematic top view of one embodiment of a first electrode and a signal transmission channel of a display panel according to the present invention;

FIG. 4 is a schematic top view of one embodiment of a first electrode and a signal transmission channel of a display panel according to the present invention;

fig. 5 is a schematic cross-sectional view illustrating a thin film transistor formed on a flexible substrate;

FIG. 6 is a schematic cross-sectional view of a first electrode formed on a thin film transistor;

fig. 7 is a schematic cross-sectional view illustrating formation of a pixel defining layer on a first electrode;

fig. 8 is a schematic cross-sectional view of forming an organic light emitting layer within a pixel opening.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus consistent with certain aspects of the present application, as detailed in the appended claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and in the claims does not indicate any order, quantity, or importance, but rather is used to distinguish one element from another. Also, the use of the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. "plurality" or "a number" means two or more. The word "comprising" or "comprises", and the like, means that the element or item listed as preceding "comprising" or "includes" covers the element or item listed as following "comprising" or "includes" and its equivalents, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

Referring to fig. 1, a display panel according to an embodiment of the present disclosure includes a flexible substrate 1, a plurality of thin film transistors 2 formed on the flexible substrate, a plurality of sub-pixel units formed on the thin film transistors, and a plurality of signal transmission channels 7, where each sub-pixel unit corresponds to one thin film transistor 2 and is electrically connected through one signal transmission channel. Each sub-pixel unit includes a first electrode 3 formed on the thin film transistor 2, a pixel defining layer 4 formed on the first electrode, an organic light emitting layer 5, and a second electrode 6 formed on the organic light emitting layer, and the thin film transistor has a signal terminal 21 electrically connected to the first electrode 3 (for example, a source drain of the thin film transistor, which means a source or a drain). Of course, the display panel further includes a hole injection layer, a hole transport layer, an electron injection layer, and the like, where the hole injection layer and the hole transport layer are located between the first electrode (which may be an anode) and the organic light emitting layer, and the electron transport layer and the electron injection layer are located between the organic light emitting layer and the second electrode (which may be a cathode). When a proper voltage is applied, the positive hole and the negative charge are combined in the organic light-emitting layer to generate light, and the three primary colors of red, green and blue RGB are generated according to different formulas to form basic colors.

Examples of the material of the flexible substrate 1 include Polyimide PI (PI) polymer, Polycarbonate PC (PC) resin, and Polyethylene terephthalate (PET) plastic.

The thin film transistor 2 may be formed by depositing various thin films, such as a semiconductor active layer, which may be selected from hydrogenated amorphous silicon (a-Si: H), polycrystalline silicon, etc., as a main material, having an energy level smaller than that of single crystal silicon (Eg ═ 1.12eV), a dielectric layer, and a metal electrode layer, on the flexible substrate 1.

The first electrode 3, for example an anode, comprises a conductive material having a high work function in order to provide a hole to the organic light emitting layer. The first electrode 3 may be made of a transparent conductive material having a high work function. The transparent conductive wire material includes a Transparent Conductive Oxide (TCO) such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Tin Zinc Oxide (ITZO), zinc oxide, tin oxide.

The pixel limiting layer 4 can be composed of an inorganic hydrophilic material and an organic hydrophobic material, and two pixel limiting layers composed of materials with different wettability are adopted, so that the solution of the organic electroluminescent material can be accurately subjected to ink-jet printing, and a thin film with uniform thickness can be formed.

The organic light-emitting layer 5 can be made of small molecule type or polymer type, and the small molecule type generally adopts vacuum evaporation method to assemble the device, which has two outstanding advantages: firstly, the molecular structure is determined, and the synthesis and purification are easy; secondly, most of the small molecular compounds are formed into films by vacuum evaporation, and compact and pure films are easy to form. The purity of the material is extremely important in electroluminescence, and the high purity of the material can reduce luminescence quenching and prolong the service life of a device, so that the luminous efficiency is improved. Further, a high-purity light-emitting material is also an important condition for realizing high-quality full-color display. The polymer type can not be evaporated, and wet film making technologies such as spin coating, inkjet printing technology, screen printing and the like are mostly adopted. Compared with vacuum evaporation, the technology has the advantages of simple process and low equipment price, thereby having cost advantage in batch production.

The second electrode 5 is, for example, a cathode, the cathode material may be an alloy cathode, a layered cathode, or a doped composite electrode, and the alloy cathode is formed by evaporating a low work function metal with active properties and a high work function metal with stable chemical properties, such as Mg: ag (10: 1), Li: Al (0.6% Li) alloy electrode, the work functions are 3.7eV and 3.2eV respectively; the layered cathode consists of a layer of extremely thin insulating material such as LiF, Li2O, MgO, Al2O3 and the like and a layer of thicker Al outside, the electron injection performance of the layered cathode is higher than that of a pure Al electrode, and higher luminous efficiency and a better I-V characteristic curve can be obtained; the doped composite electrode is characterized in that an organic layer doped with low-work-function metal is clamped between a cathode and an organic light-emitting layer, the performance of a device can be greatly improved, a typical device is ITO/NPD/AlQ (Li)/Al, the maximum brightness can reach 30000Cd/m2 (candela per square meter), and if a device without a Li-doped layer is adopted, the brightness is 3400Cd/m 2.

Referring to fig. 1 and fig. 2, each of the signal transmission channels 7 is electrically connected to a first channel 71 and a second channel 72 of the same first electrode 3, and the first channel is electrically connected to the same signal terminal 21 (for example, a source and a drain of the thin film transistor 2), and the first channel 71 and the second channel 72 are electrically connected in parallel. "coupled" may be direct or indirect, for example, where the connection is bridged by other elements or moieties. The first electrode 3 includes a first region 31 and a second region 32, the first region 311 is electrically connected to the signal terminal 21 through a first channel 71, and the second region 312 is connected to the signal terminal 21 through a second channel 72. The first channel 71 is connected to the first end 35 of the first electrode, and the second channel 72 is connected to the second end 36 of the first electrode 3, in this embodiment, the first channel 71 needs to be connected to the second end 36 of the first electrode 3 through the second channel 72, so as to be electrically connected to the signal terminal 21. The first electrodes are distributed over the pixel openings 41 in the length direction X or the width direction Y (both perpendicular to the direction Z) of the flexible substrate 1, thereby ensuring that the display device has a sufficiently large light emitting area.

In the X direction, the width d1 of the first channel is smaller than the width (dimension in the X direction) d2 of the first electrode 3, in this embodiment, the width d1 of the first channel 71 and the second channel 72 is 2-10 mm, and the ratio of the area of the signal transmission channel (sum of the areas of the first channel 71 and the second channel 72) to the area of each sub-pixel unit (i.e., the area of the first electrode) is 0.6-12%. .

When the display panel is bent in the Y direction (perpendicular to the X direction), the first electrode 3 is difficult to release the bending stress due to its large size in the X direction, and cracks (shown in fig. 2) are easily generated, so that the first region 31 is disconnected from the second region 32; the first passage 71 is small in width, receives a small stress, and is easily released, so that cracks are not easily generated. The first channel 71 can electrically connect the first region 31 and the signal terminal 21 of the thin film transistor, thereby ensuring that the first region 31 and the second region 32 can both receive the signal of the thin film transistor, ensuring that the light-emitting area is not affected by cracks, ensuring that the display panel has a sufficiently large light-emitting area, and prolonging the service life of the display panel.

Fig. 3 shows a top view of the first electrode 3A and the signal transmission channel according to another embodiment of the present application. The first electrode includes a first region 31A, a second region 32A, a third region 33A, and a fourth region 34A. The signal transmission channels include a first channel 71A, a second channel 72A, a third channel 73A, and a fourth channel 74A. The first channel 71A is electrically connected to the first region 31A and the signal terminal 21A, the second channel 72A is electrically connected to the second region 32A and the signal terminal 21A, the third channel 73A is electrically connected to the third region 33A and the signal terminal 21A, and the fourth channel 74A is electrically connected to the fourth region 34A and the signal terminal 21A. Optionally, the first channel 71A is connected to the first end 35 of the first electrode 3A, the second channel is connected to the second end 36 of the first electrode 3A, the third channel 73A is connected to the third end 37 of the first electrode, the fourth channel 74A is connected to the fourth end 38 of the first electrode, meanwhile, the first channel 71A and the third channel 73A are both connected to the second channel 72A, and the fourth channel is connected to the third channel 73A, that is, the four channels are connected in parallel. The first end 35 and the second end 36 are arranged along the Y direction, the second end 36 and the third end 37 are arranged along the X direction, the third end 37 and the fourth end 38 are arranged along the Y direction, an included angle is formed between the X direction and the Y direction, and the included angle is 90 degrees. The structure of each channel is similar, and the range of width is also 2 ~ 10 mm. Even if the organic light emitting display device is bent in the X direction or the Y direction to crack the first electrode 3A (shown in fig. 3), the first region 31A is electrically connected to the signal terminal 21A through the first channel 71A, the second region 32A is electrically connected to the signal terminal 21A through the second channel 72A, the third region 33A is electrically connected to the signal terminal 21A through the third channel 73A, and the fourth region 34A is electrically connected to the signal terminal 21A through the fourth channel 74A, so that each region can receive signals of the thin film transistor, and thus, a sufficient light emitting area is ensured.

Referring to fig. 3, the X-direction and the Y-direction may be not perpendicular, but form an acute angle or an obtuse angle, so as to be suitable for the first electrodes with different shapes (such as diamond shape).

Referring to fig. 4, another first electrode 3B and a signal transmission channel are provided in the present embodiment. The first electrode 3B includes a first region 311B, a second region 312B, and a third region 313B, the signal transmission channel includes a first channel 71B, a second channel 72B, and a third channel 73B, the first channel 71B is electrically connected to the first region 31B and the signal terminal 21B (bridged by the second channel 72B and the third channel 73B), the second channel 72B is electrically connected to the third region 31B and the signal terminal 21B, the third channel 73B is electrically connected to the second region 32B and the signal terminal 21B (bridged by the second channel 72B), and when the first region 31B, the second region 32B, and the third region 33B are disconnected from each other, the first channel 71B, the third channel 73B, and the second channel 72B can still be connected to the signal terminal 21B of the thin film transistor, so that the first region 31B, the second region 32B, and the third region 33B can all receive signals of the thin film transistor. In other embodiments, to further ensure a sufficient light emitting area not affected by the body break, the principle is similar to the embodiment shown in fig. 3, and the path between the body and the signal terminal of the thin film transistor is increased.

The present application further provides a display device, which includes the display panel of any of the foregoing embodiments, and certainly, the display device further includes a housing, a frame, a controller, and other structures, which are not described herein again.

The present application also provides a method of manufacturing a display panel, including:

s1: referring to fig. 5, a plurality of thin film transistors 2 are formed on a flexible substrate 1.

The thin film transistor 2 may be formed by depositing and etching a plurality of film layers on the flexible substrate 1. The thin film transistor 2 may be formed to include a gate, a source, a drain, etc.

S2: as shown in fig. 6, a first electrode layer is formed on the thin film transistor 2, so that the first electrode layer is electrically connected to the signal terminal 21 of the thin film transistor.

S3: with reference to fig. 2, the first electrode layer is separated into a plurality of first electrodes by a patterning process, and patterns are formed on the first electrodes to form structures such as first electrodes and the signal transmission channels. The patterning process is, for example, a patterning process including, for example, a process of coating, exposing, developing, etching, and/or stripping of a photoresist, or a printing process.

S4: referring to fig. 7, a pixel defining material is deposited on the first electrode, and then the pixel defining layer 4 is formed by etching the pixel defining material, wherein the formed pixel defining layer 4 has a plurality of pixel openings 41, and each pixel opening 41 corresponds to one pixel or sub-pixel. The first electrode 3 is entirely exposed by the pixel opening 41, and the signal transmission path is still covered by the remaining pixel defining layer 4. In other embodiments, the signal transmission channel may be selected not to be covered by the pixel defining layer.

S5: referring to fig. 8, the pixel opening 41 is filled with an organic light emitting material to form an organic light emitting layer 5. The organic light emitting layer 5 may be formed by evaporation, spin coating, inkjet printing technology, screen printing, or the like. In addition to filling in the pixel opening 41, the organic light emitting layer 5 may cover partial areas of the pixel defining layer 4 on both sides of the pixel opening 41.

In addition to the organic light emitting layer 5, a hole injection layer, a hole transport layer, an electron injection layer, and the like may be filled in the pixel opening 41, which will not be described herein.

S6: referring to fig. 1, a second electrode 6 is formed on the organic light emitting layer 5. The second electrode 6, for example, a cathode, may not be patterned, and may be formed as a continuous layer on the organic light emitting layer 5.

Through setting up two at least passageways in this application, even if first electrode when because of bending fracture, each region that the first electrode of signal end that two passageways can the electric connection thin-film transistor broke apart has improved display panel's life when guaranteeing light-emitting area.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A display panel, characterized in that: the method comprises the following steps:

a flexible substrate (1);

a plurality of thin film transistors (2) formed on the flexible substrate (1), each of the thin film transistors including a signal terminal (21);

a plurality of sub-pixel units, each of which includes a first electrode (3), each of which is formed on one thin film transistor (2);

a plurality of signal transmission channels, each of which comprises a first channel (71) and a second channel (72) electrically connected with the same first electrode (3), respectively, wherein the first channel (71) and the second channel (72) are electrically connected with the same signal end (21), respectively, the signal transmission channels and the first electrode (3) are located on the same layer, and a gap is formed between the first channel (71) and the first electrode (3);

the first channel (71) is connected to a first end (35) of the first electrode (3), the second channel (72) is connected to a second end (36) of the first electrode (3), the first end and the second end are oriented differently and are aligned along a first direction (Y).

2. The display panel of claim 1, wherein: the first channel (71) is connected to the second channel (72) and is electrically connected to the second end (36) through the second channel (72).

3. The display panel of claim 1, wherein: the first channel (71) and the second channel (72) are electrically connected in parallel.

4. The display panel of claim 1, wherein: the ratio of the area of the signal transmission channel to the area of each sub-pixel unit ranges from 0.6% to 12%.

5. The display panel of claim 4, wherein: the width range of the first channel (71) and the second channel (72) is 2-10 um.

6. The display panel of claim 1, wherein: each signal transmission channel comprises a third channel (73A), the first channel (71A), the second channel (72A) and the third channel (73A) are respectively and electrically connected with the same first electrode (3A) and the same signal end (21A), the third channel (73A) is connected with a third end (37) of the first electrode (3), the second end (36) and the third end (37) are arranged along a second direction (X), and an included angle is formed between the first direction (Y) and the second direction (X).

7. The display panel of claim 6, wherein: the first direction (Y) is perpendicular to the second direction (X).

8. The display panel of claim 6, wherein: each signal transmission channel comprises a fourth channel (74A), the first channel (71A), the second channel (72A), the third channel (73A) and the fourth channel (74A) are respectively and electrically connected with the same first electrode (3A) and the same signal end (21A), the fourth channel is connected with a fourth end (38) of the first electrode (3A), and the third end (37) and the fourth end (38) are arranged along the first direction (Y).

9. A display device, characterized in that: the display device comprising a display panel as claimed in any one of the preceding claims 1-8.