CN113077721A

CN113077721A - Display panel, manufacturing method thereof and display device

Info

Publication number: CN113077721A
Application number: CN202110413936.7A
Authority: CN
Inventors: 远新新
Original assignee: Hefei Visionox Technology Co Ltd
Current assignee: Hefei Visionox Technology Co Ltd
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2021-07-06
Anticipated expiration: 2041-04-16
Also published as: CN113077721B

Abstract

The invention discloses a display panel, a manufacturing method thereof and a display device. The display panel includes: a foldable area; a first stress buffer layer; the first stress buffer layer comprises a first stress buffer structure, the first stress buffer structure is located in the foldable area, and the first stress buffer structure comprises a plurality of grooves formed on the first stress buffer layer; the inner surface of the recess includes a plurality of raised portions. According to the embodiment of the invention, the stress of the film layer can be buffered when the display panel is folded, so that the phenomenon of uneven crease caused by folding of the display panel is reduced, the display effect is ensured, and the user experience is improved.

Description

Display panel, manufacturing method thereof and display device

Technical Field

The embodiment of the invention relates to the technical field of display, in particular to a display panel, a manufacturing method of the display panel and a display device.

Background

With the development of display technologies, display panels are continuously being developed from thin to thinner, from narrow frames to no frames, and from non-bendable to bendable. When the module material with viscoelasticity or viscoplasticity in the display panel is folded, the extrusion or stretching of each film layer by external force can generate the phenomena of slippage and the like of different layers due to the film material with mismatching, so that the display panel is creased, and the display effect is influenced.

Disclosure of Invention

The embodiment of the invention provides a display panel, a manufacturing method thereof and a display device, which are used for buffering the stress of a film layer when the display panel is folded, so that the phenomenon of uneven crease caused by folding of the display panel is reduced, the display effect is ensured, and the user experience is improved.

In order to achieve the technical purpose, the embodiment of the invention provides the following technical scheme:

a display panel, comprising: a foldable area;

a first stress buffer layer; the first stress buffer layer comprises a first stress buffer structure, the first stress buffer structure is located in the foldable area, and the first stress buffer structure comprises a plurality of grooves formed on the first stress buffer layer; the inner surface of the recess includes a plurality of raised portions.

According to the technical scheme, the first stress buffer layer is arranged in the display panel, and the groove in the first stress buffer structure and the protruding part on the inner surface of the groove can deform under stress on the first stress buffer layer, so that the stretching effect of the film layer under stress is buffered, the dislocation slippage of multiple film layers is reduced, and the probability of cracks (Crack) or creases is reduced.

Optionally, the display panel further comprises:

the second stress buffer layer is stacked with the first stress buffer layer; the second stress buffer layer comprises at least two second stress buffer structures;

the second stress buffer structure comprises a plurality of grooves formed on the second stress buffer layer; the inner surface of the groove comprises a plurality of protrusions;

the second stress buffering structures are positioned on two sides of the first stress buffering structure along the direction of the foldable edge of the display panel; the first stress buffering structure and the second stress buffering structure form a buffering group.

In this embodiment, the second stress buffering structures are disposed on two sides of the first stress buffering structure, and since the middle of the foldable area is deformed most due to the stress when the display panel is bent, the stress extends from the middle of the foldable area to two sides, the two second stress buffering structures can further buffer the stress at two sides of the first stress buffering structure; and the first stress buffer structure and the second stress buffer structure are respectively positioned in different film layers, which is equivalent to providing buffer in the thickness direction of the display panel, and is beneficial to further improving the stress buffer effect.

Preferably, the second stress buffering structures are symmetrically distributed on two sides of the first stress buffering structure along the direction of the foldable edge of the display panel; in this way, stress can be symmetrically consumed, thereby preventing dislocation slip between the film layers.

Preferably, the second stress buffer layer is located in an inner layer of the display panel, and the first stress buffer layer is located in an outer layer of the display panel; the display panel comprises an inner layer, an outer layer and a display panel, wherein the inner layer and the outer layer of the display panel are relative concepts of film layer positions, the inner layer is a film layer position far away from the external environment, and the outer layer is a film layer position close to the external environment;

preferably, along the direction of the foldable edge of the display panel, the length of the second stress buffering structure is smaller than that of the first stress buffering structure;

preferably, along the direction of the foldable edge of the display panel, the length range of the first stress buffering structure is: 4-6 mm; the length range of the second stress buffering structure is as follows: 2-3 mm.

Optionally, the first stress buffer layer includes a plurality of first stress buffer structures, and the plurality of first stress buffer structures are arranged along a direction in which a non-folding edge of the display panel is located;

preferably, the number of the buffer groups is multiple, and the multiple buffer groups are arranged along the direction of the non-folding edge of the display panel.

Optionally, the display panel includes a first substrate, a functional layer, and a first cover plate, which are stacked;

the first substrate is reused as the first stress buffer layer, and the first stress buffer structure is arranged on the first substrate; and/or the first cover plate is reused as the first stress buffer layer, and the first cover plate is provided with the first stress buffer structure.

Optionally, the display panel further comprises a second substrate disposed between the first substrate and the functional layer;

the first substrate is reused as the first stress buffer layer; and the second substrate is reused as the second stress buffer layer;

preferably, the display panel further includes: a buffer layer disposed between the first stress buffer layer and the second stress buffer layer;

preferably, the materials of the first substrate and the second substrate are both organic materials;

preferably, the materials of the first substrate and the second substrate are both polyimide.

Optionally, the display panel further comprises a second cover plate disposed between the first cover plate and the functional layer;

the first cover plate is reused as the first stress buffer layer; the second cover plate is reused as the second stress buffer layer;

preferably, the materials of the first cover plate and the second cover plate are both organic materials;

preferably, the materials of the first cover plate and the second cover plate are both transparent polyimide.

Optionally, the shape of the groove is an elliptical hemisphere, a cuboid, a trapezoidal table or a circular table;

preferably, the grooves in the first stress buffering structure are arranged in an array;

preferably, the ratio of the depth of the groove to the thickness of the first stress buffer layer ranges from: 40 to 60 percent.

Optionally, the shape of the protruding part is an elliptical hemisphere, a cone, a pyramid, a trapezoidal table or a circular table;

preferably, the protrusion is integrally provided with the first stress buffering layer;

preferably, the volume of the boss is smaller closer to the tip;

preferably, the edges of adjacent said projections are arranged in contact.

Correspondingly, an embodiment of the present invention further provides a display device, including: a display panel as provided in any of the embodiments of the present invention.

Correspondingly, the embodiment of the invention also provides a manufacturing method of the display panel, which comprises the following steps:

forming a first stress buffer layer;

patterning the part of the first stress buffer layer, which is positioned in the foldable area of the display panel, to form a plurality of grooves; the grooves form a first stress buffering structure; the inner surface of the recess includes a plurality of raised portions.

The display panel provided by the embodiment of the invention is provided with the first stress buffer layer, the first stress buffer structure is arranged in the first stress buffer layer, the first stress buffer structure comprises a plurality of grooves, and a plurality of bulges on the inner surface of each groove are combined into a sawtooth shape or a similar sawtooth shape on the inner surface of each groove. Among this first stress buffer structure, the recess can play the cushioning effect when the screen body is folded and is received the extrusion, and the recess is close to each other because of the extrusion along the both sides edge of extrusion direction, and the bellying of recess internal surface presents the gathering situation because of the extrusion to the holistic shrink effect of buffer film layer.

And in the first stress buffering structure, the surface of the groove can be stretched when the screen body is folded and is under tension, even when the screen body is under larger tension, the bulge part can approach to flattening, so that the inner surface of the groove does not have obvious saw-toothed shapes but approaches to a smooth surface, and the whole stretching effect of the buffering film layer is realized. Therefore, the groove in the first stress buffering structure and the bulge part on the inner surface of the groove can deform under stress, so that the stretching effect of the film layer under stress is buffered, and the probability of cracks (Crack) or creases is reduced. And the arrangement of the groove provides a plurality of hollow areas for the part of the first stress buffer layer, which is positioned in the foldable area, provides more bending spaces and buffer spaces for the first stress buffer layer, and can reduce the probability of folds of the film layer after bending due to incapability of recovery, thereby reducing the risk of slippage of the film layer. Therefore, compared with the prior art, the embodiment of the invention can buffer the stress of the film layer when the display panel is folded, thereby reducing the phenomenon that the display panel is uneven due to folding, ensuring the display effect and improving the user experience.

Drawings

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

fig. 2 is a schematic structural diagram of another display panel according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a stress buffer layer according to an embodiment of the present invention;

FIG. 4 is an enlarged view of region A of FIG. 3;

FIG. 5 is a schematic top view of the stress buffer layer of FIG. 3;

FIG. 6 is a schematic cross-sectional view taken along line B-B' of FIG. 3;

FIG. 7 is a schematic structural diagram of a groove under no stress according to an embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating deformation of a groove when the groove is compressed according to an embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating deformation of a groove under a tensile force according to an embodiment of the present invention;

FIG. 10 is a schematic diagram illustrating deformation of a groove under tension according to another embodiment of the present invention;

FIG. 11 is a schematic diagram illustrating deformation of a groove under an irregular force according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of another groove provided in the embodiments of the present invention;

FIG. 13 is a schematic structural diagram of another groove provided in the embodiment of the present invention;

FIG. 14 is a schematic structural diagram of another groove provided in the embodiment of the present invention;

FIG. 15 is a schematic cross-sectional view of a buffer group according to an embodiment of the present invention;

fig. 16 is a schematic top view illustrating a display panel according to an embodiment of the invention;

fig. 17 is a schematic structural diagram of another display panel according to an embodiment of the present invention;

fig. 18 is a schematic structural diagram of another display panel according to an embodiment of the present invention;

fig. 19 is a flowchart illustrating a method for manufacturing a display panel according to an embodiment of the invention;

FIG. 20 is a schematic structural diagram of a display panel formed in various steps of the manufacturing method of FIG. 19;

fig. 21 is a schematic structural diagram of a display panel formed in each step by another method for manufacturing a display panel according to an embodiment of the present invention;

fig. 22 is a schematic diagram illustrating a flat state of a display device according to an embodiment of the invention;

fig. 23 is a schematic view illustrating a state of the display device when folded according to the embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

As described in the background art, as the display panel is developed to be bendable, the flexible display screen is receiving more and more attention. New technology display screens, such as fold (Foldable) screens, roll (Rollable) screens, etc., are beginning to appear. When the module material with certain thickness and viscoelasticity or viscoplasticity is folded, the extrusion or stretching of external force can cause phenomena such as film slippage and the like between different layers due to the generation of mismatching. Therefore, the folding phenomenon, especially the phenomenon that the folding of the bright picture shows the picture projection phenomenon, is concerned about the use experience of the flexible screen. If the bad display phenomenon at the crease of the display panel is to be reduced, the stress between the films needs to be buffered and released when the different films in the display panel are dynamically stressed in a folding manner.

Accordingly, the embodiment of the invention provides a display panel, so that when the display panel is folded, the stress on a film layer is buffered better, and the film layer is prevented from slipping. Fig. 1 is a schematic structural diagram of a display panel according to an embodiment of the present invention. Referring to fig. 1, the display panel includes: a substrate 70, a functional layer 50 and a cover plate 80 are arranged in a stack. The functional layer 50 may include a display functional layer and/or a touch functional layer. In the intrinsic film layer of the display panel, a first stress buffer layer 10 may be added to achieve stress buffering when the display panel is bent. The first stress buffer layer 10 includes a first stress buffer structure 11 therein. Illustratively, as shown in fig. 1, the first stress buffer layer 10 may be disposed between the substrate 70 and the functional layer 50 to effectively buffer the substrate 70 when folded. Alternatively, fig. 2 is a schematic structural diagram of another display panel provided in the embodiment of the present invention. As shown in fig. 2, the first stress buffer layer 10 may be disposed between the cover plate 80 and the functional layer 50 to effectively buffer the cover plate 80 when folded.

It should be noted that the first stress buffer layer 10 is not limited to be disposed in the present invention, and in other embodiments, the display panel may include a multi-layer substrate 70 and/or a multi-layer cover plate 80, and the substrate 70 at the bottom layer may be disposed on a base plate. Then, the first stress buffer layer 10 may also be disposed between different substrates 70 or between the substrate 70 and a base plate; or, between different cover plates 80; still alternatively, the first stress buffer layer 10 may have a plurality of layers, which are respectively disposed between the substrate and the substrate 70, between different substrates 70, between the substrate 70 and the functional layer 50, between the functional layer 50 and the cover plate 80, and between different cover plates 80, so as to simultaneously achieve a buffer effect on the substrate 70 and the cover plate 80. Next, the structure of the stress relaxation layer will be explained.

Fig. 3 is a schematic structural diagram of a stress buffer layer according to an embodiment of the present invention; FIG. 4 is an enlarged view of region A of FIG. 3; FIG. 5 is a schematic top view of the stress buffer layer of FIG. 3; fig. 6 is a schematic cross-sectional view taken along line B-B' in fig. 3. Referring to fig. 3 to 6, the display panel includes: a foldable region 1 and a non-foldable region 2; the number and the position relation of the foldable area 1 and the non-foldable area 2 are various, and the number and the position relation can be set according to actual requirements. For example, as shown in fig. 3, two non-folding regions 2 are provided, one foldable region 1 is provided, and the foldable region 1 is located between the adjacent non-folding regions 2, and the foldable region 1 may be provided with a rotation shaft of a folding screen, for example. For another example, the number of the foldable areas 1 is at least two, the number of the non-foldable areas 2 is one more than the number of the foldable areas 1, and each foldable area 1 is respectively located between two adjacent non-foldable areas 2, so that the display panel realizes multi-fold display. The foldable side defining the display panel is the side of the display panel that can be folded short. In a top view plane, a direction Y in which the non-folding edge of the display panel is located is perpendicular to a direction X in which the folding edge of the display panel is located. Then, as for the folding axis, the side folded to be folded is located in the direction X of the foldable side of the display panel, and the side not folded to be folded is located in the direction Y of the non-folded side of the display panel. It should be noted that, along the direction X of the foldable edge of the display panel, the length of the foldable area 1 is smaller than the length of the non-foldable area 2. Preferably, the length of the foldable area 1 is much smaller than the length of the non-foldable area 2, for example, the length of the non-foldable area 2 is 50 times or more of the length of the foldable area 1, i.e. the foldable area 1 occupies a smaller proportion of the whole display area. Generally, compared with the foldable area 1, the non-foldable area 2 has a better display effect, and thus the area of the foldable area 1 is reduced, and the display effect of the display panel is improved. In the drawings, in order to clearly illustrate the film layer structure in the foldable area 1, the film layer thickness, the length of the foldable area 1 and the like are amplified and are only shown as schematic diagrams, but do not represent actual sizes, and the actual sizes of the film layers in the display panel can be set according to requirements.

As shown in fig. 3 to 6, the display panel includes a first stress buffer layer 10, the first stress buffer layer 10 includes a first stress buffer structure 11, the first stress buffer structure 11 is located in the foldable area 1, the first stress buffer structure 11 includes a plurality of grooves 110 formed on the first stress buffer layer 10; the inner surface 112 of the recess 110 includes a plurality of raised portions 111.

For example, the grooves 110 may exhibit a certain regular arrangement in the first stress buffering structure 11, such as a matrix arrangement shown in fig. 3, or a staggered array arrangement; other arrangements are possible. Fig. 3 only shows that the first stress buffering structure 11 includes six grooves 110 by way of example, in practical applications, the number of the grooves 110 in the first stress buffering structure 11 may be set as required, for example, the number of the grooves 110 is set to be much larger than six. Alternatively, the protrusions 111 in the groove 110 are distributed on the inner surface 112 of the groove 110, or distributed over the inner surface 112 of the groove 110.

In the process of bending the display panel, the tensile stress and the compressive stress in the groove 110 can be mutually offset; the hollow nature of the recess 110 itself allows the recess 110 to deform to relieve stresses when subjected to such stresses. And, the plurality of protrusions 111 form a zigzag shape or a zigzag-like shape on the inner surface 112 of the groove 110, and the plurality of protrusions 111 can be gathered when being pressed and spread when being stretched to improve the cushioning effect of the groove 110. Therefore, the groove 110 and the plurality of protrusions 111 on the inner surface 12 thereof serve as buffer units in the first stress buffer structure 11, and can buffer the stress applied to the first stress buffer layer 10 during bending; the risk of cracks or creases in the foldable area 1 is reduced. And, the arrangement of the groove 110 enables a plurality of hollow regions to appear at the part of the first stress buffer layer 10 located in the foldable area 1, so as to provide more bending spaces and buffer spaces for the first stress buffer layer 10, thereby reducing the slip tendency between the first stress buffer layer 10 and the adjacent membrane layers, and making the slippage between the membrane layers not easy to occur.

Hereinafter, the deformation of one groove 110 will be described in detail, which may occur when the groove 110 is subjected to different forces.

Fig. 7 is a schematic structural diagram of a groove provided in an embodiment of the present invention when the groove is not stressed, and fig. 8 is a schematic structural diagram of a groove provided in an embodiment of the present invention when the groove is deformed when the groove is pressed. In which fig. 7 and 8 are schematic views of one groove 110 in fig. 3, unlike fig. 3, only the convex portion 111 at the edge of the groove 110 is shown in fig. 7 and 8, and the convex portion 111 inside the groove 110 is not shown. The direction in which the first stress buffer layer 10 is compressed is indicated by an arrow. Referring to fig. 7 and 8, when the display panel is folded, the groove 110 is compressed, and the groove 110 is more easily deformed than other portions of the first stress buffering layer 10. In the first stress buffering structure 11, the groove 110 is used as a buffer, and the deformation amount generated by extrusion in the left and right directions of the groove 110 is large; and the stress in the up-down direction is small, and the deformation amount is low. The plurality of protrusions 111 may be gathered when pressed (as indicated by the dashed blocks on both sides in fig. 8), thereby buffering the contraction effect. Because the position of the groove 110 (the first stress buffering structure 11) generates large deformation when being stressed, and the deformation of other areas of the first stress buffering layer 10 due to stress is small, the slippage phenomenon of the film layer can be reduced, and the Crack or crease can be prevented.

Fig. 9 is a schematic diagram of deformation of the groove when a tensile force is applied to the groove according to an embodiment of the present invention, and arrows indicate a direction in which the first stress buffering layer 10 is stretched. Combine fig. 7 and 9. When the display screen body is folded and the groove 110 is stretched, the deformation quantity generated by stretching the groove 110 (the first stress buffering structure 11) in the two side directions is larger; and the stress in the up-down direction is small, and the deformation amount is low. Moreover, the plurality of protrusions 111 can be largely deformed when being stretched, and even be flattened (for example, the protrusions 111 at two sides), so that the stretching effect is buffered. Because the position of the groove 110 (the first stress buffering structure 11) generates large deformation when being stressed, the stress on other areas of the first stress buffering layer 10 is small, thereby reducing the slippage phenomenon of the film layer and preventing Crack or crease from occurring.

Fig. 10 is a schematic diagram of deformation of another groove under tensile force according to the embodiment of the present invention, and arrows indicate the force direction of the first stress buffering layer 10; unlike the pulling force in fig. 9, the groove in fig. 10 is subjected to the pulling forces in the up-down direction and the left-right direction, and the force state shown in fig. 10 may occur in the case where the folding axis provides a strong pulling force. With reference to fig. 7 and 10, when the groove 110 is subjected to strong tensile forces from multiple directions, the amount of deformation of the groove 110 itself toward the periphery is large; and the larger the strong tensile force is, the larger the stretching amount of the convex portions 111 is, and all the convex portions 111 tend to be completely flattened. The inner surface of the groove 110 and the projections 111 together constitute an infinite surface that approaches a smooth circle regardless of the stress limit of the tensile stress (the surface of all the projections 111 that is connected to the inner surface 112 of the groove 110 that is not covered with the projections 111 may be referred to as the surface of the groove 110).

Fig. 11 is a schematic diagram of deformation of a groove under an irregular stress according to an embodiment of the present invention, and an arrow indicates a stress direction of the first stress buffer layer 10. Referring to fig. 7 and 11, when the groove 110 is subjected to different tensile or compressive forces from different directions, the plurality of protrusions 111 may be gathered together at the pressed portion; in the stretched portion, the projection 111 may be stretched. In combination with the above effects, the surface of the groove 110 is deformed to form an irregular surface.

In summary, in the display panel provided in the embodiment of the invention, the first stress buffering layer 10 is disposed, the first stress buffering structure 11 is disposed in the first stress buffering layer 10, the first stress buffering structure 11 includes a plurality of grooves 110, and the plurality of protrusions 111 on the inner surface 112 of each groove 110 are combined into a zigzag shape or a zigzag-like shape on the inner surface 112 of the groove 110. In the first stress buffering structure 11, the groove 110 may play a role of buffering when the screen body is folded and squeezed, two side edges of the groove 110 along the squeezing direction are close to each other due to squeezing, and the protrusion 111 on the inner surface 112 of the groove 110 is in a gathering state due to squeezing, so as to buffer the overall contraction effect of the film layer.

And, in this first stress buffering structure 11, the surface of the groove 110 can be stretched when the screen body is folded and is under tension, even when under a larger tension, the protrusion 111 can tend to be flattened, so that there is no longer a distinct saw-tooth shape on the inner surface 112 of the groove 110, but it is close to a smooth surface, thereby buffering the overall stretching effect of the film layer. Therefore, the groove 110 in the first stress buffering structure 11 and the protrusion 111 on the inner surface 112 thereof can deform under stress, so as to buffer the stretching effect of the film under stress, and reduce the probability of cracks or creases. In addition, the arrangement of the groove 110 provides a plurality of hollow regions for the part of the first stress buffer layer 10 located in the foldable area 1, provides more bending spaces and buffer spaces for the first stress buffer layer 10, and can reduce the probability of wrinkles generated due to the fact that the film cannot be recovered after being bent, thereby reducing the risk of slippage of the film. Therefore, the embodiment of the invention can buffer the stress of the film layer when the display panel is folded, thereby reducing the phenomenon of uneven crease caused by folding the display panel, ensuring the display effect and improving the user experience.

In addition to the above embodiments, there are various configurations of the concave groove 110 and the convex portion 111, and some of them will be described below, but the present invention is not limited thereto.

With continued reference to fig. 7, in one embodiment, the edges of adjacent projections 111 are optionally disposed in contact (corresponding to extending over the inner surface 112 of the recess 110). The protruding portions 111 are main structures for reducing stress, so that the number of the protruding portions 111 is large, which is beneficial to further relieving the stress on the whole first stress buffer layer 10 and reducing the risk of cracks or creases in the foldable area 1.

Optionally, the groove 110 and the plurality of protrusions 111 thereon are integrally formed on the first stress buffering layer 10; when the first stress buffer layer 10 is patterned by using a process such as etching, the groove 110 including the protrusion 111 is directly formed. When the groove 110 is stressed, the protrusion 111 can deform along with the deformation of the stress buffer layer 10 to relieve the stress of the first stress buffer layer 10, and prevent the first buffer layer 10 from sliding. The closer the projection 111 is to the tip, the smaller the volume; that is, the bottom surface of the protrusion 111 with a larger area is connected to the inner surface 112 of the groove 110, so as to prevent the protrusion 111 from falling off when a force is applied.

In one embodiment, the shape of the groove 110 is optionally a hemisphere (i.e., an elliptical hemisphere with the same curvature), with a semicircular cross-section (as shown in FIG. 6); alternatively, the groove 110 is shaped like a rectangular parallelepiped, and the cross section thereof is rectangular or square (as shown in fig. 12); alternatively, the shape of the groove 110 is an elliptical hemisphere with different curvature, and the cross section thereof is a semiellipse (as shown in fig. 13); alternatively, the groove 110 may be shaped as a trapezoidal or truncated cone having a trapezoidal cross-section (as shown in fig. 14).

In one embodiment, the ratio of the depth D1 of the groove 110 to the thickness D2 of the first stress buffer layer 10 optionally ranges from 40% to 60%, such as 40%, 45%, 50%, 55%, or 60%. Specifically, the smaller the depth D1 of the groove 110 is, the shallower the hollow portion of the groove 110 is, and the smaller the effect of buffering deformation is; if the depth D1 of the groove 110 is larger, the thickness of the first stress buffer layer 10 at the bottom of the groove 110 is smaller, and the first stress buffer layer 10 is more likely to be broken, thereby affecting the display effect. Therefore, in the embodiment of the invention, the ratio of the depth D1 of the groove 110 to the thickness D2 of the first stress buffer layer 10 is 40% to 60%, so as to ensure that the buffer effect of the groove 110 and the first stress buffer layer 10 are not broken when being bent.

Illustratively, as shown in fig. 12, the depth D1 of the groove 110 occupies 60% of the thickness D2 of the first stress buffer layer 10; as shown in fig. 13, the depth D1 of the groove 110 occupies 50% of the thickness D2 of the first stress-buffer layer 10; as shown in fig. 14, the depth D1 of the groove 110 occupies 40% of the thickness D2 of the first stress-buffer layer 10. Illustratively, the thickness D2 of the first stress buffer layer 10 ranges from: 10-20 μm, such as 10 μm, 12 μm, 14 μm, 16 μm, 18 μm or 20 μm; the depth D1 of the groove 110 ranges from: 4-12 μm, such as 4 μm, 6 μm, 8 μm, 10 μm or 12 μm; .

In one embodiment, the shape of the protruding portion 111 is optionally a cone or a pyramid (the bottom surface is an arbitrary polygon), and the cross section thereof is a triangle (as shown in fig. 6 or fig. 14); alternatively, the shape of the protruding portion 111 is a trapezoidal table or a circular truncated cone, and the cross section thereof is trapezoidal (as shown in fig. 12); alternatively, the shape of the convex portion 111 is an elliptical hemisphere, the cross section of which is a semiellipse (as shown in fig. 13); when the two foci of the ellipse coincide, the shape of the convex portion 111 is a hemisphere, and its cross section is a semicircle.

Various structures of the groove 110 and the protrusion 111 are exemplarily shown in the above embodiments, and the specific shape and size thereof can be selected according to the requirements in practical applications. It should be noted that, in the same groove 110, the protruding portions 111 may be provided in one shape and size, or a combination of a plurality of protruding portions 111 may be adopted. Similarly, in the same first stress buffering structure 11, one shape and size of the groove 110 may be provided, or a combination of a plurality of grooves 110 may be adopted, which is not limited herein.

Fig. 15 is a schematic cross-sectional structure view of a buffer set according to an embodiment of the invention. Referring to fig. 15, on the basis of the above embodiments, optionally, the display panel further includes a second stress buffer layer 20, and the second stress buffer layer 20 is stacked with the first stress buffer layer 10.

The second stress buffer layer 20 includes at least two second stress buffer structures 21. The second stress buffering structure 21 is disposed in a similar manner to the first stress buffering layer 11, specifically, the second stress buffering structure 21 includes a plurality of grooves formed on the second stress buffering layer 20; the inner surface of the recess includes a plurality of raised portions. The specific structure of the groove and the protrusion can be referred to the above description of the first stress buffering structure 11, and will not be described herein again.

Along the direction X of the foldable edge of the display panel, the second stress buffering structures 21 are positioned at two sides of the first stress buffering structure 11; the first stress buffering structure 11 and the second stress buffering structure 21 constitute a buffer group 100.

When the display panel is bent, the stress received in the middle of the foldable area 1 is the largest, the stress extends from the middle of the foldable area 1 to two sides, the second stress buffering structures 21 are arranged on two sides of the first stress buffering structure 11, the stress at two sides of the first stress buffering structure 11 can be further buffered through the two second stress buffering structures 21, namely, when the display panel is bent, the first stress buffering structure 11 and the second stress buffering structure 21 in the buffering group 100 are linked, so that the foldable area 1 in a wider range can be better buffered. And, the first stress buffering structure 11 and the second stress buffering structure 21 are respectively located in different film layers, which is equivalent to providing buffering in the thickness direction of the display panel, and is beneficial to further improving the stress buffering effect. Therefore, in the embodiment of the present invention, the buffer group 100 is formed by three stress buffering structures, and the three stress buffering structures jointly act when the display panel is bent, so that the buffering effect can be further improved.

With reference to fig. 15, on the basis of the foregoing embodiments, optionally, along the direction X where the foldable edge of the display panel is located, the second stress buffering structures 21 are symmetrically distributed on two sides of the first stress buffering structure 11, so as to achieve the same buffering effect on the stress on two sides of the first stress buffering structure 11.

With continued reference to fig. 15, on the basis of the above embodiments, optionally, along the direction X where the foldable edge of the display panel is located, the length L2 of the second stress buffering structure 21 is smaller than the length L1 of the first stress buffering structure 11. This is because when the display panel is bent, the stress applied to the middle position of the foldable area 1 is the largest, and the first stress buffering structure 11 located in the middle is used as a main structure for relieving the stress, and the length L1 of the first stress buffering structure 11 is set to be larger; and the stress on the two sides of the foldable area is smaller, so that the length L2 of the second stress buffering structure 21 can be set to be smaller adaptively, and the buffering effect is improved as a whole. Illustratively, along the direction X of the foldable edge of the display panel, the length L1 of the first stress buffering structure 11 ranges from: 4-6mm, such as 5 mm; the length L2 of the second stress buffering structure 21 ranges from: 2-3mm, such as 2.5 mm; the length L2 of the second stress buffering structure 21 is preferably half of the length L1 of the first stress buffering structure 11.

Fig. 15 exemplarily shows that along the direction X of the foldable edge of the display panel, the projection of the second stress buffering structure 21 in the thickness direction of the display panel is adjacent to the projection of the first stress buffering structure 11 in the thickness direction of the display panel, and is not a limitation of the present invention. In other embodiments, the position relationship between the second stress buffering structure 21 and the first stress buffering structure 11 may also be adjusted, for example, the second stress buffering structure 21 and the first stress buffering structure 11 may have a slight overlap or no overlap. Fig. 16 is a schematic top view of a display panel according to an embodiment of the invention. Referring to fig. 16, based on the above embodiments, optionally, the first stress buffer layer 10 includes a plurality of first stress buffer structures 11, and the plurality of first stress buffer structures 11 are arranged along the direction Y where the non-folding edge of the display panel is located. This arrangement facilitates the distribution of the first stress buffering structures 11 over the foldable area 1. The shape and structure of the grooves 110 in the first stress buffering structures 11 and the shape and structure of the protrusions 111 thereon may be different, and the size and the distance between the first stress buffering structures 11 may also be different, so as to buffer the stress at different positions; and the structure of the first stress buffer layer 10 is more various and can be flexibly selected. In other embodiments, the length of the first stress buffering structure 11 along the direction Y of the non-folding edge of the display panel may be equal to the length of the foldable area 1, so that only one first stress buffering structure 11 is disposed on the first stress buffering layer 10.

With continued reference to fig. 16, on the basis of the above embodiments, optionally, the number of the buffer groups 100 is multiple, and the multiple groups of the buffer groups 100 are arranged along the direction Y where the non-folding edge of the display panel is located. In different buffer groups 100, the corresponding positions of the first stress buffer structure 11 and the second stress buffer structure 21 may be different, so that the corresponding structures of the first stress buffer layer 10 and the second stress buffer layer 20 are more various and can be flexibly selected.

On the basis of the foregoing embodiments, optionally, the display panel includes a first substrate, a functional layer, and a first cover plate which are stacked; the first substrate is reused as a first stress buffer layer, and a first stress buffer structure is arranged on the first substrate; and/or the first cover plate is reused as a first stress buffer layer, and a first stress buffer structure is arranged on the first cover plate. According to the embodiment of the invention, a new film layer is not required to be added in the display panel, and the patterning process is directly carried out on the substrate layer or the cover plate layer to form the stress buffer structure, so that on one hand, the number of the film layers in the display panel can be effectively reduced, and the overall thickness of the display panel is reduced. On the other hand, the stress buffer structure arranged on the substrate layer or the cover plate layer does not affect the electrical property of a Thin Film Transistor (TFT) device in a pixel circuit in the display panel, reduces stress generated during folding, and reduces damage to display of the TFT device.

In addition to the above embodiments, optionally, the display panel further includes a second substrate disposed between the first substrate and the functional layer. The first substrate is reused as a first stress buffer layer and the second substrate is reused as a second stress buffer layer. Alternatively, the display panel further includes a second cover plate disposed between the first cover plate and the functional layer. The first cover plate is reused as a first stress buffer layer, and the second cover plate is reused as a second stress buffer layer. The first stress buffering structure in the first stress buffering layer and the second stress buffering structure in the second stress buffering layer form a buffering group, linkage buffering is achieved when bending is conducted, and buffering effects are improved.

Optionally, the first substrate, the second substrate, the first cover plate and the second cover plate are all made of organic materials, so that compared with other materials such as metal, the flexibility of the organic materials is better, the influence of external stress can be consumed inside in the bending or flattening process, and the stress buffer layer is less prone to fracture; and the recovery characteristic is better, and the stress buffer layer is easier to recover the original shape after being bent, and is not easy to generate wrinkles, thereby reducing the risk of slippage between films. For example, the material of the first substrate and the second substrate may be Polyimide (PI); the material of the first cover plate and the second cover plate may be polyimide, preferably transparent polyimide.

In the above embodiments, the first stress buffer layer 10 and the second stress buffer layer 20 are exemplarily shown to be in direct contact, and the invention is not limited thereto. In practical applications, the arrangement of the first stress buffer layer 10 and the second stress buffer layer 20 may be adjusted according to the specific arrangement of the display panel. Fig. 17 is a schematic structural diagram of another display panel according to an embodiment of the present invention. Referring to fig. 17, in one embodiment, the display panel optionally includes a first substrate 10-1, a buffer layer 30, and a second substrate 20-1, which are stacked. The buffer layer 30 is used to buffer the first substrate 10-1 and the second substrate 20-1, and the material of the buffer layer 30 may be an inorganic material such as silicon nitride (SiN) or silicon oxide (SiO). The first substrate 10-1 is reused as a first stress buffer layer, a first stress buffer structure 11-1 is arranged on the first stress buffer layer, the second substrate 20-1 is reused as a second stress buffer layer, and two second stress buffer structures 21-1 are arranged on the second stress buffer layer; the first stress buffering structure 11-1 and the two second stress buffering structures 21-1 form a buffering group 100-1. In the embodiment of the present invention, since the display panel itself includes the first substrate 10-1 and the second substrate 20-1 which are stacked, the first stress buffering structure 11-1 and the second stress buffering structure 21-1 may be respectively disposed in the two film layers. That is, the present embodiment utilizes the structural characteristics of the display panel itself, and the buffer group 100-1 is disposed in the display panel, so as to achieve a better buffer effect.

Fig. 18 is a schematic structural diagram of another display panel according to an embodiment of the present invention. Referring to fig. 18, in an embodiment, the display panel optionally includes a lower screen module layer 60, a first substrate 10-1, a buffer layer 30, a second substrate 20-1, a functional layer 50, a second cover plate 20-2, a glue layer 40, and a first cover plate 10-2, which are stacked.

Wherein, the Cover plate (CWF) is used as the packaging layer of the display screen body for packaging and protecting the display panel and avoiding the corrosion of water and oxygen. The first cover plate 10-2 and the second cover plate 20-2 are attached through a glue layer 40; illustratively, the adhesive layer 40 may be made of a transparent adhesive material. The functional layer 50 may include: a display functional layer and/or a touch functional layer. The display panel may be, for example, an Organic Light Emitting Diode (OLED) display panel, such as an Active Matrix Organic Light Emitting Diode (AMOLED) display panel. The display function layer may include an array circuit layer and a light emitting device layer; the touch control functional layer can be compounded in the display functional layer or can be independently arranged on the display functional layer. Illustratively, the underscreen module layer 60 may include: cameras, etc.

In one embodiment, optionally, the first cover plate 10-2 is reused as a first stress buffer layer on which the first stress buffer structure 11-2 is disposed, and the second cover plate 20-2 is reused as a second stress buffer layer on which two second stress buffer structures 21-2 are disposed; the first stress buffering structure 11-2 and the two second stress buffering structures 21-2 form a buffering group 100-2. In the embodiment, the buffer group 100-2 is arranged in the display panel by utilizing the structural characteristics of the display panel, so that a better buffer effect can be realized.

With continued reference to fig. 18, in another embodiment, optionally, the first substrate 10-1 is reused as a first stress buffer layer and the first cover plate 10-2 is reused as a first stress buffer layer; the second substrate 20-1 is reused as a second stress buffer layer and the second cover plate 20-2 is reused as a second stress buffer layer. Therefore, the stress buffering structures are arranged in all the organic film layers of the display panel, and the buffering effect can be better realized. Specifically, the buffer group 100-2 is arranged at the top of the display panel, the buffer group 100-1 is arranged at the bottom of the display panel, and no matter the display panel is bent upwards or downwards, the buffer groups are matched by at least two buffer groups, so that a better buffer effect can be realized.

With continued reference to fig. 18, on the basis of the above embodiments, optionally, the second stress buffer layer 20 is located at an inner layer of the display panel, and the first stress buffer layer 10 is located at an outer layer of the display panel. Wherein, the inner layer refers to a position close to the middle film layer in the display panel; i.e. the inner film of the display panel, the film close to the inside and far away from the external environment. The outer layer refers to a film layer close to the edge of the display panel and a film layer closer to the external environment; i.e. the outer edge film layer of the display panel, such as the film layers near the upper and lower end surfaces. As shown in fig. 18, the first substrate 10-1 and the first cover plate 10-2 are located at the outer layer of the display panel; in contrast, the second substrate 10-2 and the second cover plate 20-2 are located at inner layers of the display panel. Set up like this for no matter display panel upwards buckles or buckle downwards, all be longer first stress buffer structure and bear the great stress of skin, in order to realize better buffering effect.

The embodiment of the invention also provides a manufacturing method of the display panel, which is suitable for the display panel provided by any embodiment of the invention and has corresponding beneficial effects. Fig. 19 is a flowchart illustrating a method for manufacturing a display panel according to an embodiment of the invention; fig. 20 is a schematic structural diagram of a display panel formed in each step of the manufacturing method in fig. 19. Referring to fig. 19 and 20, the method for manufacturing the display panel includes the following steps:

and S110, forming a first stress buffer layer 10.

The material of the first stress buffer layer 10 is an organic material with good flexibility, such as polyimide. Optionally, the thickness range of the first stress buffer layer 10 is: 10-20 μm; such as 10 μm, 12 μm, 14 μm, 16 μm, 18 μm or 20 μm.

For example, the first stress buffer layer 10 may be formed on the substrate using a coating process; or forming the first stress buffer layer 10 on a corresponding film layer of the display panel, such as forming the first stress buffer layer 10 on the display functional layer or the touch functional layer.

S120, patterning the part, located in the foldable area 1 of the display panel, of the first stress buffer layer 10 to form a plurality of grooves 110; the plurality of grooves 110 constitute a first stress buffering structure 11; the inner surface 112 of the recess 110 includes a plurality of raised portions 111.

The process of patterning the first stress buffer layer 10 may be an etching process, and specifically may be a half-tone mask etching process, so that the groove 110 is formed and the protrusion 111 is formed on the inner surface 112 of the groove 110. Optionally, the ratio of the depth of the groove 110 to the thickness of the first stress buffer layer 10 ranges from: 40% -60%, such as 40%, 45%, 50%, 55% or 60%, to ensure the buffer effect of the groove 110 and ensure that the first stress buffer layer 10 is not broken when being bent. The shape enclosed by the inner surface 112 of the groove 110 may be an elliptical hemisphere, a cuboid, a trapezoidal frustum, or a truncated cone. The shape of the protruding portion 111 may be an elliptical hemisphere, a cone, a pyramid, a trapezoidal table, or a circular truncated cone.

Preferably, the first substrate may be reused as the first stress buffer layer, and the patterning is directly performed on the portion of the foldable area 1 of the first substrate to form the plurality of grooves 110. Alternatively, the first cover plate may be reused as the first stress buffer layer, and the patterning may be directly performed on the portion of the foldable area 1 of the first cover plate to form the plurality of grooves 110.

Alternatively, the grooves 110 may be arrayed on the first stress buffering structure 11; the convex portion 111 may be provided integrally with the first stress relaxation layer 11; the closer the projection 111 is to the tip, the smaller the volume; the edges of adjacent bosses 111 are arranged in contact.

In the method for manufacturing a display panel according to the embodiment of the present invention, the first stress buffer layer 10 is formed first, and then the first stress buffer layer 10 is patterned to form the first stress buffer structure 11, where the first stress buffer structure 11 includes a plurality of grooves 110, and a plurality of protrusions 111 on an inner surface 112 of each groove 110 are combined into a zigzag shape or a zigzag-like shape on the inner surface 112 of each groove 110. In the first stress buffering structure 11, the groove 110 can play a role of buffering when the screen body is folded and extruded, two side edges of the groove 110 along the extrusion direction are close to each other due to extrusion, and the convex part 111 on the inner surface 112 of the groove 110 is in a gathering state due to extrusion, so that the overall contraction effect of the buffer film layer is achieved; in the first stress buffering structure 11, the surface of the groove 110 may be stretched when the screen body is folded and is under a pulling force, and when the pulling force is gradually increased, the protrusion 111 is more nearly flattened, so that the inner surface 112 of the groove 110 no longer has a distinct saw-tooth shape, but is close to a smooth surface, thereby buffering the overall stretching effect of the film layer. In addition, the arrangement of the groove 110 provides a plurality of hollow regions for the part of the first stress buffer layer 10 located in the foldable area 1, provides more bending spaces and buffer spaces for the first stress buffer layer 10, and can reduce the probability of wrinkles generated due to the fact that the film cannot be recovered after being bent, thereby reducing the risk of slippage of the film. Therefore, the embodiment of the invention can buffer the stress of the film layer when the display panel is folded, thereby reducing the phenomenon of uneven crease caused by folding the display panel, ensuring the display effect and improving the user experience.

Fig. 21 is a schematic structural diagram of a display panel formed in each step by another display panel manufacturing method according to an embodiment of the present invention. Referring to fig. 21, in an embodiment, a method for manufacturing a display panel optionally includes the following steps:

s210, forming a first stress buffer layer 10.

In which a first stress buffer layer 10 may be formed on a substrate using a coating process. Or the display panel originally comprises a first substrate and a first cover plate; in practical applications, the first substrate and/or the first cover plate can be reused as the first stress buffer layer 10 to achieve a buffering effect without adding a film layer.

S220, patterning the part, located in the foldable area 1 of the display panel, of the first stress buffer layer 10 to form a plurality of grooves 110; the plurality of grooves 110 constitute a first stress buffering structure 11; the inner surface 112 of the recess 110 includes a plurality of raised portions 111.

And S230, forming a second stress buffer layer 20.

Wherein, the material of the second stress buffer layer 20 may be the same as the material of the first stress buffer layer 10. Illustratively, the second stress buffer layer 20 may be formed on another substrate using a coating process. As shown in fig. 21, the first stress relaxation layer 10 and the second stress relaxation layer 20 have their grooved surfaces facing each other to form a relaxation group 100. Therefore, it is necessary to form the first stress buffer layer 10 and the second stress buffer layer 20 on different substrates, and then to arrange the two layers oppositely after patterning the two layers.

Illustratively, the display panel originally includes a second substrate, which is disposed in a stacked manner with the first substrate; and/or a second cover plate which is arranged in a stacking way with the first cover plate. In practical applications, the second substrate and/or the second cover plate can be reused as the second stress buffer layer 20 to achieve a buffering effect without adding a film layer.

S240, patterning the part, located in the foldable area 1 of the display panel, of the second stress buffer layer 20 to form two second stress buffer structures 21; wherein the second stress buffering structure 21 comprises a plurality of grooves 210; the inner surface 212 of the recess 210 includes a plurality of raised portions 211.

The second stress buffering structure 21 is similar to the first stress buffering structure 11 in specific structure. Optionally, the length of the second stress buffering structure 21 is smaller than the length of the first stress buffering structure 11 along the direction X where the foldable edge of the display panel is located. Illustratively, the length range of the first stress buffering structure is: 4-6mm, such as 4mm, 4.5mm, 5mm, 5.5mm or 6 mm; the length range of the second stress buffering structure is as follows: 2-3mm, such as 2mm, 2.5mm or 3 mm. The length of the second stress buffering structure may be maintained at half the length of the first stress buffering structure 11.

S250, attaching the surface of the first stress buffer layer 10 with the first stress buffer structure 11 and the surface of the second stress buffer layer 20 with the second stress buffer structure 21 in an aligning manner, so that the first stress buffer layer 10 and the second stress buffer layer 20 are arranged in a stacking manner; in the direction X along the foldable edge of the display panel, the second stress buffering structures 21 are located at two sides of the first stress buffering structure 11, and the first stress buffering structure 11 and the second stress buffering structure 21 form a buffering group 100.

Along the direction X of the foldable edge of the display panel, the projection of the second stress buffering structure 21 in the thickness direction of the display panel and the projection of the first stress buffering structure 11 in the thickness direction of the display panel may be overlapped or adjacent or not, and may be set according to actual requirements.

It should be noted that the sequence of S210-250 is only one possible embodiment provided by the present invention, and is not meant to limit the present invention. In other embodiments, the order of preparation may be adjusted or combined as desired.

It should be noted that, in the above embodiments, the surface of the first stress buffer layer 10 having the first stress buffer structure 11 and the surface of the second stress buffer layer 20 having the second stress buffer structure 21 are aligned and attached to each other, which is not a limitation of the present invention. In other embodiments, the surface of the first stress buffer layer 10 having the first stress buffer structure 11 may be opposite to the surface of the second stress buffer layer 20 not having the second stress buffer structure 21, so that the second stress buffer layer 20 may be directly formed on the display panel on which the first stress buffer layer 10 is formed, and the second stress buffer layer 20 is patterned, thereby avoiding the step of attaching the first stress buffer layer 10 and the second stress buffer layer 20 in an aligned manner, and simplifying the process flow.

An embodiment of the present invention further provides a display device, including: the display panel provided by any embodiment of the invention has corresponding beneficial effects. Fig. 22 is a schematic diagram illustrating a flat state of a display device according to an embodiment of the invention; fig. 23 is a schematic view illustrating a state of the display device when folded according to the embodiment of the present invention. Illustratively, the display device may be a Foldable screen or a Rollable screen. The display device including one foldable area 1 and two non-foldable areas 2 is exemplarily shown in fig. 22 and 23, and the foldable area 1 is located between the two non-foldable areas 2, but not limited to the present invention. In other embodiments, it may also be provided that the display device comprises a plurality of foldable areas 1.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A display panel, comprising: a foldable area;

2. The display panel according to claim 1, further comprising:

the second stress buffering structures are positioned on two sides of the first stress buffering structure along the direction of the foldable edge of the display panel; the first stress buffering structure and the second stress buffering structure form a buffering group;

preferably, the second stress buffering structures are symmetrically distributed on two sides of the first stress buffering structure along the direction of the foldable edge of the display panel;

3. The display panel according to claim 2, wherein the first stress buffer layer comprises a plurality of first stress buffer structures, and the plurality of first stress buffer structures are arranged along a direction in which a non-folding edge of the display panel is located;

4. The display panel according to claim 2, wherein the display panel comprises a first substrate, a functional layer, and a first cover plate which are stacked;

5. The display panel according to claim 4, further comprising a second substrate provided between the first substrate and the functional layer;

6. The display panel according to claim 4, further comprising a second cover plate disposed between the first cover plate and the functional layer;

7. The display panel according to claim 1,

the groove is in the shape of an elliptic hemisphere, a cuboid, a trapezoidal table or a round table;

8. The display panel according to claim 1,

the shape of the convex part is an elliptical hemisphere, a cone, a pyramid, a trapezoidal table or a round table;

preferably, the volume of the boss is smaller closer to the tip;

preferably, the edges of adjacent said projections are arranged in contact.

9. A display device, comprising: the display panel of any one of claims 1-8.

10. A method for manufacturing a display panel is characterized by comprising the following steps:

forming a first stress buffer layer;