CN111063715B

CN111063715B - Flexible display panel

Info

Publication number: CN111063715B
Application number: CN201911319184.7A
Authority: CN
Inventors: 金江江
Original assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2022-07-12
Anticipated expiration: 2039-12-19
Also published as: CN111063715A

Abstract

A flexible display panel comprises an array substrate, a pixel defining layer, a light emitting layer and an encapsulating layer, wherein a plurality of pixel openings are formed in the pixel defining layer, part of the pixel openings comprise at least one special-shaped side wall, the special-shaped side wall comprises at least one curved surface and an inclined surface connected with the curved surface, the curved surface forms a groove relative to the special-shaped side wall, and the light emitting layer and the encapsulating layer cover the groove. Through setting up anomalous groove structure on the open-ended lateral wall on pixel definition layer for the packaging layer deposit forms the pattern similar to claw structure in the recess, is favorable to improving the cohesiveness of packaging layer and luminescent material layer and array substrate, and then effectively reduces because of the stress of buckling production between packaging layer and the luminescent material layer, thereby promotes flexible display device's reliability.

Description

Flexible display panel

Technical Field

The invention relates to the technical field of display, in particular to a flexible display panel.

Background

Since an Organic Light-Emitting Diode (OLED) has the advantages of self-luminescence, high contrast, fast response speed, wide temperature application range, and the like, the OLED is widely applied to the display industry, and compared with other display technologies, the OLED is easier to realize flexible display. The biggest challenge of the flexible OLED display at present is the stress and adhesion problem among the film layers, each film layer on the display element and the film layers are stripped due to the stress and adhesion problem in the bending or folding process, once the film layers are stripped, organic materials and active metals in the OLED display device are oxidized to form black spots and gradually expand, and the performance of the OLED display device is affected.

In order to reduce bending stress, a polarizer of a bending region is usually removed in the structure of an existing OLED device, or a groove is formed in the bending region on a flexible substrate to relieve stress in the bending process, but the two designs can cause obvious difference in chromaticity of the bending region and a non-bending region, so that the phenomenon of uneven chromaticity is caused.

Disclosure of Invention

The invention provides a flexible display panel, which aims to solve the technical problem that the performance of a display device is influenced by peeling or breaking of film layers in the bending process of the flexible display panel due to poor bending stress and poor adhesion among multiple film layers of the conventional flexible display panel.

In order to solve the above problems, the technical scheme provided by the invention is as follows:

the invention provides a flexible display panel, which comprises an array substrate, a pixel definition layer arranged on the thin film transistor array substrate, a light-emitting layer arranged on the pixel definition layer, and an encapsulation layer covering the light-emitting layer, wherein the pixel definition layer is arranged on the thin film transistor array substrate; the pixel definition layer is provided with a plurality of pixel openings, the light emitting layer comprises a plurality of sub-pixels, and the plurality of sub-pixels correspond to the plurality of pixel openings one by one; wherein, part of the pixel openings comprise at least one special-shaped side wall, the special-shaped side wall comprises at least one curved surface and an inclined surface connected with the curved surface, the curved surface forms a groove relative to the special-shaped side wall, and the luminous layer and the packaging layer cover the groove.

In at least one embodiment of the present invention, an auxiliary opening is disposed between two adjacent sub-pixels, and the auxiliary opening includes at least one of the irregular sidewalls.

In at least one embodiment of the present invention, the auxiliary opening is disposed at a periphery of the sub-pixel.

In at least one embodiment of the invention, the profiled side wall comprises a curved surface and an inclined surface connecting the curved surfaces from top to bottom.

In at least one embodiment of the invention, the profiled side wall comprises two continuous curved surfaces and one sloping surface from top to bottom.

In at least one embodiment of the present invention, an included angle between a connection line of midpoints of upper and lower ends of the curved surface and a plane where the array substrate is located is an acute angle.

In at least one embodiment of the present invention, a portion of the pixel openings includes four shaped sidewalls disposed opposite to each other in pairs.

In at least one embodiment of the present invention, the encapsulation layer includes a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer sequentially disposed on the light emitting layer.

In at least one embodiment of the present invention, the first inorganic encapsulation layer and the organic encapsulation layer both cover the recess.

In at least one embodiment of the present invention, the thickness of the first inorganic encapsulation layer is 0.5 to 1.5 micrometers, and the thickness of the organic encapsulation layer is 4 to 20 micrometers.

According to the invention, the irregular groove structure is arranged on the side wall of the opening on the pixel definition layer, so that the packaging layer is deposited in the groove to form a pattern similar to a claw structure, the improvement of the cohesiveness of the packaging layer, the luminescent material layer and the array substrate is facilitated, the stress generated by bending between the packaging layer and the luminescent material layer is further effectively reduced, and the reliability of the flexible display device is improved.

Drawings

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

Fig. 1 is a schematic structural diagram of a flexible display panel according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a pixel definition layer according to an embodiment of the invention;

FIG. 3 is a top view of a pixel structure according to an embodiment of the invention;

FIG. 4 is a top view of a pixel structure according to another embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a pixel definition layer according to another embodiment of the present invention;

fig. 6 is a schematic structural diagram of a flexible display panel according to another embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all 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 application.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact of the first and second features, or may comprise contact of the first and second features not directly but through another feature in between. Also, the first feature "on," "above" and "over" the second feature may include the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

The invention aims at the technical problem that the performance of a display device is influenced by the fact that film layers of the flexible display panel are peeled or broken in the bending process due to poor bending stress and poor adhesion among the film layers of the conventional flexible display panel.

As shown in fig. 1, an embodiment of the invention provides a flexible display panel 100, which includes an array substrate 10, a pixel definition layer 20 disposed on the array substrate 10, a light emitting layer 30 disposed on the pixel definition layer 20, and an encapsulation layer 40 disposed on the light emitting layer 30.

As shown in fig. 2, a plurality of pixel openings 201 are disposed on the pixel defining layer 20, and the light emitting layer 30 includes a plurality of sub-pixels, which correspond to the plurality of pixel openings one-to-one.

The light emitting layer 30 includes an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting material layer, an electron transport layer, an electron injection layer, a cathode, a light coupling-out material layer, and a lithium fluoride film layer, which are sequentially disposed on the array substrate 10, and the pixel opening 201 is used to accommodate a partial structure of the light emitting layer 30, such as the hole injection layer, the hole transport layer, the electron blocking layer, the light emitting material layer, the electron transport layer, and the electron injection layer.

The encapsulation layer 40 includes a first inorganic encapsulation layer 41, an organic encapsulation layer 42, and a second inorganic encapsulation layer 43 sequentially stacked on the light emitting layer 30, the first inorganic encapsulation layer 41 covers the light emitting layer 30, and the second inorganic encapsulation layer 43 covers the first inorganic encapsulation layer 41 and the organic encapsulation layer 42.

The bending stress among the film layers is a key factor for realizing a flexible bendable display product, and particularly, the stress among the flexible substrate, the luminescent material film layer and the film packaging film layer is large in the bending process, and the risk of peeling among the film layers is large.

As shown in fig. 2, in particular, the sidewall of the pixel opening 201 is modified, a part of the pixel opening 201 includes at least one shaped sidewall 21, the shaped sidewall 21 includes at least one curved surface 211 and an inclined surface 212 connecting the curved surface 211, the curved surface 211 forms a groove 210 with respect to the shaped sidewall 21, and the curved surface 211 corresponds to a bottom of the groove 210 and a peripheral wall surrounding the bottom.

In this embodiment, the number of the grooves 210 of one of the irregular side walls 21 is one, that is, one of the irregular side walls 21 includes one curved surface 211 and an inclined surface 212 connected to the curved surface 211 from top to bottom, the groove 210 provides an accommodating space for a subsequently prepared film layer, so that the subsequently prepared film layer covers the groove 210, and the subsequently prepared film layer forms a claw-like pattern on the irregular side wall 21, which is beneficial to improving the adhesion between the film layers.

The groove 210 is filled with a part of the structure (e.g., cathode) of the light-emitting layer 30 and a part of the film layer of the encapsulation layer 40, and generally, the thickness of the entire film layer of the light-emitting layer 30 is smaller than the thickness of the encapsulation layer 40 and the thickness of the pixel defining layer 20, so that the groove 210 cannot be filled with the light-emitting layer 30, and therefore, a part of the film layer of the encapsulation layer 40 is also filled in the groove 210.

Since a part of the structure of the light emitting layer 30 is only disposed in the pixel opening 201 (the light emitting layer 30 in fig. 1 is only a schematic view of the whole structure), such as a light emitting material layer, and other structures extend in the length direction of the pixel defining layer 20, such as a cathode structure, only a part of the film layer of the light emitting layer 30 covers the groove 210, and a pattern similar to a claw is formed at the groove 210, so as to improve the adhesion of the film layer, and further improve the adhesion between the light emitting layer 30 and the array substrate 10.

The thickness of the first inorganic packaging layer 41 is 0.5-1.5 micrometers, the thickness of the organic packaging layer 42 is 4-20 micrometers, the thickness of the second inorganic packaging layer 43 can be kept the same as that of the first inorganic packaging layer 41, the first inorganic packaging layer 41 and the second inorganic packaging layer 43 are used for blocking water and oxygen, but the stress of inorganic materials is large, and therefore the organic packaging layer 42 is arranged between the two inorganic packaging layers and used for relieving bending stress. Since the organic encapsulation layer 42 is used to relieve stress, the film thickness of the organic encapsulation layer 42 is larger than that of the first inorganic encapsulation layer 41, so that the first inorganic encapsulation layer 41 and the organic encapsulation layer 42 also fill the groove 210, and a pattern similar to a claw is formed at the groove 210 to improve the grip.

The vertical opening depth of the curved surface 211 relative to the array substrate 10 is smaller than the thickness of the pixel defining layer 20, an included angle α between a connecting line AB between midpoints of upper and lower ends of the curved surface 211 and a plane where the array substrate 10 is located is an acute angle, that is, the groove 210 is obliquely arranged relative to the sidewall of the pixel defining layer 20, and the obliquely arranged groove 210 enables a subsequently formed claw pattern to be oblique, so that the oblique adhesion is firmer relative to the vertical adhesion.

In this embodiment, four of the irregular sidewalls 201 are disposed in one pixel opening 201, four corresponding grooves 210 are disposed in pairs and are respectively disposed on the irregular sidewalls 21 in the front, rear, left, and right directions of the pixel opening 201, and four curved surfaces 211 are disposed on the same horizontal plane.

As shown in fig. 3, the light-emitting layer 30 includes a plurality of red sub-pixels 31, green sub-pixels 32, and blue sub-pixels 33 arranged in an array, each sub-pixel corresponds to one of the pixel openings 201, and each sub-pixel of one color is adjacent to another sub-pixel of two colors, respectively, to realize a color display.

Each of the pixel openings 201 is provided with the irregular-shaped sidewall 21, that is, each of the pixel openings 201 is provided with the groove 210, in other embodiments, the grooves 210 may be arranged every other one of the sub-pixels, and the density of the grooves 210 may be set according to actual design requirements.

As shown in fig. 4, on the basis of this embodiment, in other embodiments, a plurality of auxiliary openings 202 are further disposed at intervals on the pixel defining layer 20, each of the auxiliary openings 202 includes at least one of the irregular sidewalls 21, the auxiliary opening 202 and the corresponding groove 210 on the irregular sidewall 21 are covered by a part of the film layers (e.g., the cathode) of the light emitting layer 30 and the encapsulation layer 40, so as to further improve adhesion between the film layers, and the auxiliary opening 202 is not provided with the film layers such as the light emitting material layer, i.e., the auxiliary opening 202 is not used for displaying.

The auxiliary openings 202 may be disposed at the periphery of the sub-pixels of the same color, and adjacent to the sub-pixels of the other two colors, and may be disposed at intervals of one sub-pixel of the color in the transverse or longitudinal direction. For example, the auxiliary openings 202 are disposed at the periphery of the green sub-pixels 32 and adjacent to the red sub-pixels 31 and the blue sub-pixels 33, and the auxiliary openings 202 are disposed at intervals of one green sub-pixel 32 in the lateral direction.

In other embodiments, the auxiliary opening 202 may be disposed on the periphery of each sub-pixel, the auxiliary openings 202 may also be disposed every other sub-pixel, and the density of the auxiliary openings 202 may be set according to actual needs, which is not limited herein.

In other embodiments, as shown in fig. 5 and 6, the shaped sidewall comprises two continuous curved surfaces (a first curved surface 2111 and a second curved surface 2112) and one inclined surface 212 from top to bottom, and the second curved surface 2112 is connected to the inclined surface 212. By arranging two gradients of the grooves 210 from top to bottom in series, two claw-like patterns are formed, and the film layer gripping force can be further improved.

In other embodiments, five curved surfaces which are arranged in series and have different curvature radians may be disposed on the irregular-shaped sidewall 21 to form a pattern similar to a human hand, so as to improve the gripping force of the luminescent layer 30 and the encapsulation layer which are prepared subsequently.

The array substrate 10 includes a flexible substrate and a thin film transistor array disposed on the flexible substrate, and the flexible substrate is made of any one of polyvinyl alcohol, polyimide, and polyester.

The material of the first inorganic encapsulation layer 41 and the second inorganic encapsulation layer 43 is SiN_x、SiO_x、SiON_x、SiCN_x、Al₂O₃、TiO₂、ZrO₂Any one or more combinations thereof.

The organic package layer 42 is made of any one of an acrylic material, an epoxy resin material and an organic silicon material.

Has the advantages that: through setting up anomalous groove structure on the open-ended lateral wall on pixel definition layer for the packaging layer deposit forms the pattern similar to claw structure in the recess, is favorable to improving the cohesiveness of packaging layer and luminescent material layer and array substrate, and then effectively reduces because of the stress of buckling production between packaging layer and the luminescent material layer, thereby promotes flexible display device's reliability.

In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.

Claims

1. A flexible display panel, comprising:

an array substrate;

the pixel definition layer is arranged on the array substrate and provided with a plurality of pixel openings;

the light-emitting layer is arranged on the pixel defining layer and comprises a plurality of sub-pixels, the sub-pixels correspond to the pixel openings one by one, and the light-emitting layer at least comprises an anode, a hole injection layer, a hole transport layer, a light-emitting material layer, an electron transport layer, an electron injection layer and a cathode; and

an encapsulation layer covering the light emitting layer; wherein, the first and the second end of the pipe are connected with each other,

part of the pixel openings comprise at least one special-shaped side wall, the special-shaped side wall comprises at least one curved surface and an inclined surface connected with the curved surface, the curved surface forms a groove relative to the special-shaped side wall, and the cathode of the light emitting layer and the packaging layer sequentially cover the groove;

an auxiliary opening is arranged between two sub-pixels which are partially adjacent, and the auxiliary opening comprises at least one special-shaped side wall;

the cathode and the packaging layer of the light-emitting layer sequentially cover the auxiliary opening and the groove on the special-shaped side wall corresponding to the auxiliary opening, and the light-emitting material layer is not arranged in the auxiliary opening;

the auxiliary openings are arranged on the periphery of the sub-pixels of the same color, are adjacent to the sub-pixels of the other two colors, and are arranged at intervals of one sub-pixel of the color in the transverse direction or the longitudinal direction.

2. The flexible display panel of claim 1, wherein the shaped sidewall comprises a curved surface and a slope connecting the curved surfaces from top to bottom.

3. The flexible display panel of claim 1, wherein the shaped sidewall comprises two continuous curved surfaces and a slope from top to bottom.

4. The flexible display panel according to claim 1, wherein an included angle between a connecting line of midpoints of upper and lower ends of the curved surface and a plane where the array substrate is located is an acute angle.

5. The flexible display panel of claim 1, wherein a portion of the pixel openings comprise four shaped sidewalls disposed opposite each other in pairs.

6. The flexible display panel of claim 1, wherein the encapsulation layer comprises a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer sequentially disposed on the light emitting layer.

7. The flexible display panel of claim 6, wherein the first inorganic encapsulation layer and the organic encapsulation layer both cover the groove.

8. The flexible display panel according to claim 7, wherein the first inorganic encapsulation layer has a thickness of 0.5 to 1.5 μm, and the organic encapsulation layer has a thickness of 4 to 20 μm.