CN109524561B

CN109524561B - Flexible display screen and display device

Info

Publication number: CN109524561B
Application number: CN201811139360.4A
Authority: CN
Inventors: 古春笑
Original assignee: Yungu Guan Technology Co Ltd
Current assignee: Yungu Guan Technology Co Ltd
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2021-04-02
Anticipated expiration: 2038-09-28
Also published as: CN109524561A

Abstract

The embodiment of the invention relates to the technical field of display, and discloses a flexible display screen and a display device. The flexible display screen comprises a flexible substrate and a light-emitting unit formed on the flexible substrate, wherein the light-emitting unit comprises a first electrode, a second electrode and a light-emitting layer arranged between the first electrode and the second electrode; the first electrode and/or the second electrode comprise a first conducting layer, a second conducting layer and at least one conducting connecting block, and the conducting connecting block is connected between the first conducting layer and the second conducting layer; the sum of the projection areas of all the conductive connecting blocks on the first conductive layer is smaller than the area of the first conductive layer, and the sum of the projection areas of all the conductive connecting blocks on the second conductive layer is smaller than the area of the second conductive layer, so that a gap exists between the first conductive layer and the second conductive layer. The gap can release stress when the screen body is bent, the stress is prevented from being accumulated in the first electrode and/or the second electrode, and the risk that the first electrode and/or the second electrode is broken or peeled from other film layers is reduced.

Description

Flexible display screen and display device

Technical Field

The embodiment of the invention relates to the technical field of display, in particular to a flexible display screen and a display device.

Background

The flexible display screen is popular with many consumers due to its characteristics of lightness, thinness, flexibility, good mechanical properties and the like. The first electrode and the second electrode in the flexible display screen are used as important devices in the flexible display screen, and are usually formed by selecting materials with weak elasticity, and the bending capability and the adhesion are poor. In the process of bending the flexible display screen, the stress and the tension applied to the first electrode and the second electrode cannot be released, and the stress and the tension are gathered in the first electrode and the second electrode, so that the first electrode and/or the second electrode generate cracks or the bonding force between the first electrode and other films is weakened. After that, the stress generated when the flexible display screen is bent continues to be accumulated in the first electrode and the second electrode, and finally the first electrode and/or the second electrode are cracked or peeled from other film layers, thereby affecting the normal display of the flexible display screen.

Disclosure of Invention

An object of an embodiment of the present invention is to provide a flexible display panel and a display device, so as to enhance the bending resistance of a first electrode and/or a second electrode, thereby reducing the risk of the first electrode and/or the second electrode breaking or peeling from other film layers, and improving the reliability of the flexible display panel.

In order to solve the above technical problem, an embodiment of the present invention provides a flexible display screen, including: the light-emitting unit comprises a first electrode, a second electrode and a light-emitting layer arranged between the first electrode and the second electrode; the first electrode and/or the second electrode comprise: the conductive connecting block is connected between the first conductive layer and the second conductive layer; and the sum of the projection areas of all the conductive connection blocks on the first conductive layer is smaller than the area of the first conductive layer, and the sum of the projection areas of all the conductive connection blocks on the second conductive layer is smaller than the area of the second conductive layer.

The embodiment of the invention also provides a display device which comprises the flexible display screen.

Compared with the prior art, the embodiment of the invention enables the first electrode and/or the second electrode to comprise: the conductive connection structure comprises a first conductive layer, a second conductive layer and at least one conductive connection block connected between the first conductive layer and the second conductive layer, wherein the sum of the projection areas of all conductive connection blocks on the first conductive layer is smaller than the area of the first conductive layer, and the sum of the projection areas of all conductive connection blocks on the second conductive layer is smaller than the area of the second conductive layer, so that a gap exists between the first conductive layer and the second conductive layer. When the flexible display screen is bent, the gap can release stress during bending, and stress is prevented from being accumulated in the first electrode and/or the second electrode, so that stress borne by the first electrode and/or the second electrode is reduced, and the risk of breakage or peeling of the first electrode and/or the second electrode from other film layers is favorably reduced.

In addition, the elastic modulus of the first conducting layer and the elastic modulus of the second conducting layer are smaller than the elastic modulus of the conducting connecting block.

In addition, the height of the first electrode and/or the second electrode is 140-200 nm.

In addition, the height of the conductive connecting block is 100-150 nm. The height range can ensure that the first electrode and/or the second electrode have enough bending resistance, and simultaneously can ensure that the height of the conductive connecting block can not greatly increase the overall thickness of the flexible display screen.

In addition, each first electrode and/or each second electrode comprises a plurality of conductive connecting blocks, and the plurality of conductive connecting blocks are arranged between the first conductive layer and the second conductive layer at intervals. On the one hand, a plurality of conductive connecting blocks are arranged between the first conductive layer and the second conductive layer, so that the stability of the first electrode and/or the second electrode is improved, on the other hand, the plurality of conductive connecting blocks are arranged at intervals, a plurality of gap channels can be isolated between the first conductive layer and the second conductive layer, when the flexible display screen is bent, each gap channel can release stress during bending, and the stress borne by the first electrode and/or the second electrode can be reduced to a greater extent.

In addition, a plurality of the conductive connecting blocks are arranged at equal intervals.

In addition, the distance between two adjacent conductive connecting blocks is 15-20 μm.

In addition, a buffer for absorbing stress is arranged in a gap between the first conducting layer and the second conducting layer, and the elastic modulus of the buffer is smaller than that of the first conducting layer and that of the second conducting layer. The smaller the elastic modulus is, the larger the elasticity is, when the flexible display screen is bent, the buffer with the larger elasticity can be preferentially deformed to absorb the stress during bending, so that the stress is further prevented from being accumulated in the first electrode and/or the second electrode, and the bending resistance of the first electrode and/or the second electrode is further improved.

In addition, at least one hole for releasing stress is arranged on the first conducting layer or the second conducting layer. When the flexible display screen is bent, the edge of the hole arranged on the first conducting layer or the second conducting layer can release stress, the stress is further prevented from being accumulated in the first electrode and/or the second electrode, and the bending resistance of the first electrode and/or the second electrode can be further improved.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

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

fig. 2 is a schematic structural view of a first electrode according to a first embodiment of the present invention;

FIGS. 3(a), (b) are schematic cross-sectional views of a first electrode according to a first embodiment of the present invention;

FIG. 4 is a schematic cross-sectional view of a first electrode according to a second embodiment of the invention;

FIG. 5 is a top view of a first electrode according to a third embodiment of the present invention;

fig. 6 is a schematic view of a display device according to a fourth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present application in various embodiments of the present invention. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments.

A first embodiment of the invention relates to a flexible display screen.

As shown in fig. 1, 2 and 3, the flexible display panel includes a flexible substrate 1 and a light-emitting unit formed on the flexible substrate 1, wherein the light-emitting unit includes a first electrode 2, a second electrode 8 and a light-emitting layer 6 disposed between the first electrode 2 and the second electrode 8; wherein the first electrode 2 and/or the second electrode 8 comprises: the conductive connection block C is connected between the first conductive layer A and the second conductive layer B, the sum of the projection areas of all the conductive connection blocks C on the first conductive layer A is smaller than the area of the first conductive layer A, and the sum of the projection areas of all the conductive connection blocks C on the second conductive layer B is smaller than the area of the second conductive layer B. Therefore, a gap exists between the first conductive layer a and the second conductive layer B, and when the flexible display screen is bent, the gap can release stress during bending, so that stress is prevented from being accumulated in the first electrode 2 and/or the second electrode 8, and the stress borne by the first electrode 2 and/or the second electrode 8 is favorably reduced, thereby effectively reducing the risk that the first electrode 2 and/or the second electrode 8 is broken or peeled from other film layers.

It should be noted that fig. 1 and 2 are schematic diagrams illustrating the first electrode 2 including a first conductive layer a, a second conductive layer B and at least one conductive connection block C. However, the present embodiment is not limited thereto, and in practical applications, the second electrode 8 may also include a first conductive layer a, a second conductive layer B, and at least one conductive connection block C (it can be understood that specific shapes of the first conductive layer a, the second conductive layer B, and the conductive connection block C in the second electrode 8 may be adjusted according to practical situations).

In the present embodiment, the first electrode 2 includes a first conductive layer a, a second conductive layer B and at least one conductive connection block C, and it is understood that, when the second electrode 8 includes a first conductive layer a, a second conductive layer B and at least one conductive connection block C, the following description of the first conductive layer a, the second conductive layer B and the conductive connection block C in the first electrode 2 is equally effective and can produce the same effect on the first conductive layer a, the second conductive layer B and the conductive connection block C in the second electrode 8.

Specifically, when the number of the conductive connection blocks C connected between the first conductive layer a and the second conductive layer B is 1, the conductive connection blocks C may be connected to intermediate positions of the first conductive layer a and the second conductive layer B, respectively, to enhance the stability of the overall structure of the first electrode 2. At this time, the first electrode 2 has an i-shaped cross section (see fig. 3 (a)).

When the number of the conductive connection blocks C connected between the first conductive layer a and the second conductive layer B is plural (at least 2), the plural conductive connection blocks C may be arranged at intervals, and the cross section of the first electrode 2 is h-shaped (see fig. 3 (B)). On the one hand, set up a plurality of electrically conductive connecting blocks C between first conducting layer A and second conducting layer B, help further improving the stability of first electrode 2 overall structure, on the other hand, set up a plurality of electrically conductive connecting blocks C interval, can keep apart a plurality of clearance passageways between first conducting layer A and second conducting layer B, when flexible display screen buckles, stress when every clearance passageway can both release buckling, compare in single electrically conductive connecting block C, this kind of structure can reduce the stress that first electrode 2 bore at bigger degree, strengthen the bending resistance of first electrode 2. In this embodiment, the distance between two adjacent conductive connection blocks C can be controlled between 15-20 μm. Preferably, the plurality of conductive connection blocks C may be disposed at equal intervals.

It should be noted that, when the cross section of the first electrode 2 is i-shaped or multi-fold, the bending resistance of the first electrode 2 is proportional to the height H1 of the conductive connection block C, the width D1 of the first conductive layer a, and the width D2 of the second conductive layer B, but the inventor found that it is better to increase the height H1 of the conductive connection block C than to increase the width D1 of the first conductive layer a or the width D2 of the second conductive layer B, and therefore, in practical applications, the bending resistance of the first electrode 2 can be preferentially increased by increasing the height H1 of the conductive connection block C. In this embodiment, the height H1 of the conductive connection block C can be controlled within the range of 100-150nm, and the overall height H2 of the first electrode 2 can be controlled within the range of 140-200nm, which can ensure that the first electrode 2 has sufficient bending resistance, and at the same time, can ensure that the height of the conductive connection block C does not greatly increase the overall thickness of the flexible display panel. In this embodiment, the width D1 of the first conductive layer a and the width D2 of the second conductive layer B can be 200-300 times the height H1 of the conductive connection block C. In practical applications, the width D1 of the first conductive layer a may be equal to or different from the width D2 of the second conductive layer B, which is not limited in this embodiment.

In this embodiment, different conductive materials may be selected to form the first conductive layer a, the second conductive layer B and the conductive connection block C, wherein the elastic modulus of the materials forming the first conductive layer a and the second conductive layer B may be smaller than the elastic modulus of the materials forming the conductive connection block C (i.e., the elastic modulus of the first conductive layer a and the elastic modulus of the second conductive layer B are smaller than the elastic modulus of the conductive connection block C), so as to increase the overall bending resistance of the first electrode 2. In practical application, the first conductive layer a and the second conductive layer B can be formed by using a flexible ITO transparent conductive film, and the conductive connection block C can be formed by using a metal such as silver (Ag), magnesium (Mg), aluminum (Al), or the like. However, the first conductive layer a, the second conductive layer B and the conductive connection block C may be formed of the same material, and the elastic modulus of the first conductive layer a, the elastic modulus of the second conductive layer B and the elastic modulus of the conductive connection block C are the same.

With continued reference to fig. 1, the light-emitting unit further includes a TFT layer 3, a planarization layer 4, a pixel defining layer 5, a support pillar 7, and a protective cover layer 9. Wherein the TFT layer 3 is disposed on the flexible substrate 1; the planarization layer 4 is provided on the TFT layer 3; the first electrode 2 is disposed on the planarization layer 4; the pixel defining layer 5 covers the peripheral edge portion of the first electrode 2 and exposes the middle portion of the first electrode 2; the middle part of the first electrode 1 and the pixel defining layer 5 enclose a containing part with an open top, and the light emitting layer 6 is arranged in the containing part; the support posts 7 are disposed on the pixel defining layer 5; the second electrode 8 is disposed on the pixel defining layer 5 and the light emitting layer 6; the protective cover 9 covers the second electrode 8 and the support posts 7. The first electrode 2 and the second electrode 8 jointly drive the light-emitting layer 6.

The TFT layer 3 specifically includes an active layer 31, a gate insulating layer 32, a gate electrode 33, an interlayer insulating layer 34, a source electrode 35, and a drain electrode 36. The active layer 31 is disposed on the flexible substrate 1, the gate insulating layer 32 is disposed on the active layer 31, the gate electrode 33 is disposed on the gate insulating layer 32, and the interlayer insulating layer 34 is disposed on the gate electrode 33. One end of the source electrode 35 and one end of the drain electrode 36 are connected through the active layer 31, and the other end of the source electrode 35 and the other end of the drain electrode 36 sequentially penetrate through the gate insulating layer 32 and the interlayer insulating layer 34 and extend into the planarization layer 4. A via is provided in the planarization layer 4 through the planarization layer 4 (as shown at D in fig. 1, the first electrode 2 is electrically connected to the source 35 or drain 36 (the connected pole can be selected depending on whether the TFT is N-type or P-type).

In this embodiment, the flexible substrate 1 may be formed of a polymer material such as Polyimide (PI), Polycarbonate (PC), Polyethersulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), Polyarylate (PAR), or glass Fiber Reinforced Plastic (FRP). The flexible substrate 1 may be transparent, translucent, or opaque to provide support for the formation of various film layers disposed thereon.

The active layer 31 in the TFT layer may be an Indium Gallium Zinc Oxide (IGZO) layer.

The gate insulating layer 32 may be an inorganic layer formed of, for example, silicon oxide, silicon nitride, or metal oxide, and the gate insulating layer 32 may have a single-layer or multi-layer structure.

The gate electrode 33 may have a single or multi-layered structure formed of gold (Au), silver (Ag), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), aluminum (Al), molybdenum (Mo), or chromium (Cr), or a layer structure formed of an alloy such as an aluminum (Al) neodymium (Nd) alloy, a molybdenum (Mo) tungsten (W) alloy, or the like. It should be noted that, in practical applications, a capacitor metal layer (not shown) is further disposed on the gate 33, and a capacitor insulating layer (not shown) is further disposed between the gate 33 and the capacitor metal layer, wherein the capacitor insulating layer may be an inorganic layer, such as a single-layer structure or a mixed-layer structure formed by silicon oxide (SiOx) or silicon nitride (SiNx). The capacitor insulating layer forms a first capacitor plate in a partial region of the gate 33 and forms a second capacitor plate in a capacitor metal layer to form a plate capacitor.

The interlayer insulating layer 34 is specifically located on the capacitance metal layer, and may be formed of an insulating inorganic material such as silicon oxide or silicon nitride, and the interlayer insulating layer 34 may also be a single-layer or multi-layer structure.

The planarization layer 4 may be an organic layer formed of acryl, Polyimide (PI), benzocyclobutene (BCB), or the like.

The pixel defining layer 5 (also referred to as a pixel defining layer) for forming each pixel electrode may be formed of an organic material such as Polyimide (PI), Polyamide (PA), benzocyclobutene (BCB), acryl resin, or phenol resin.

The light emitting layer 6 may be formed of a low molecular weight organic material or a high molecular weight organic material, and the organic light emitting layer 7 includes an organic emission layer, however, the organic light emitting layer 7 may include other various functional layers, such as at least one of a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an Electron Transport Layer (ETL), and an Electron Injection Layer (EIL), in addition to the organic emission layer.

The supporting pillars 7 may have an inverted trapezoidal structure with a wide top and a narrow bottom, that is, the surface area of the side of the supporting pillars 7 away from the pixel defining layer 5 is larger than the surface area of the side of the supporting pillars 7 close to the pixel defining layer 5. In practical applications, the supporting posts 7 may also be formed of an organic material such as Polyimide (PI), Polyamide (PA), benzocyclobutene (BCB), acryl resin, or phenol resin.

The protective cover layer 9 may have a single-layer or multi-layer structure formed of silicon oxide, silicon nitride oxide, silicon oxynitride, or the like, and the protective cover layer 9 serves to block water, oxygen, total reflection of light emitted from the light-emitting layer 6, or the like.

Compared with the prior art, the present embodiment makes the first electrode and/or the second electrode include: the conductive connection structure comprises a first conductive layer, a second conductive layer and at least one conductive connection block connected between the first conductive layer and the second conductive layer, wherein the sum of the projection areas of all conductive connection blocks on the first conductive layer is smaller than the area of the first conductive layer, and the sum of the projection areas of all conductive connection blocks on the second conductive layer is smaller than the area of the second conductive layer, so that a gap exists between the first conductive layer and the second conductive layer. When the flexible display screen is bent, the gap can release stress during bending, and stress is prevented from being accumulated in the first electrode and/or the second electrode, so that stress borne by the first electrode and/or the second electrode is reduced, and the risk of breakage or peeling of the first electrode and/or the second electrode from other film layers is favorably reduced.

A second embodiment of the invention relates to a flexible display screen. The second embodiment is a further improvement on the first embodiment, and the main improvement is that: the second embodiment also has a buffer 10 (shown in fig. 4) for absorbing stress in the gap between the first conductive layer a and the second conductive layer B.

The first electrode 2 includes a first conductive layer a, a second conductive layer B and at least one conductive connection block C.

Specifically, if the elastic modulus of the first conductive layer a and the elastic modulus of the second conductive layer B are smaller than the elastic modulus of the conductive connection block C, the buffer 10 may be formed by a material having an elastic modulus smaller than the elastic modulus of the first conductive layer a and the second conductive layer B, so that the elasticity of the buffer 10 is greater than the elasticity of each portion of the first electrode 2, and thus when the flexible display panel is bent, the buffer 10 having a greater elasticity will deform before the first electrode 2, so as to absorb the stress during bending, thereby further avoiding the stress from being accumulated in the first electrode 2, and facilitating further improving the bending resistance of the first electrode 2. If the elastic modulus of the first conductive layer a, the second conductive layer B, and the conductive connection block C are the same, a material having an elastic modulus smaller than those of the first conductive layer a, the second conductive layer B, and the conductive connection block C may be selected to form the buffer 10.

In practical applications, the material with an elastic modulus of 200-300MPa may be selected to form the cushion 10. The material can be an organic flexible material, the organic flexible material is good in elasticity, the elasticity of the buffer 10 can be guaranteed, the adhesion is strong, the increase of the adhesion between the buffer 10 and the first electrode 2 is facilitated, and the first electrode 2 can be prevented from being peeled off when the flexible display screen is bent. The organic flexible material can be organic glue, such as Polyimide (PI), acrylate and the like.

Compared with the first embodiment, the buffer for absorbing stress is arranged in the gap between the first conductive layer and the second conductive layer, which is favorable for further avoiding stress from being accumulated in the first electrode and/or the second electrode, and improving the bending resistance of the first electrode and/or the second electrode.

A third embodiment of the invention relates to a flexible display screen. The third embodiment is a further improvement on the first embodiment or the second embodiment, and the main improvement is that: in the third embodiment, at least one hole 11 for releasing stress is formed in the first conductive layer a or the second conductive layer B (fig. 5 illustrates an example of forming the hole 11 in the first conductive layer a).

Specifically, at least one hole 11 is provided on the first conductive layer a or the second conductive layer B, and when the flexible display panel is bent, the edge of the hole 11 can release stress, thereby further avoiding stress from being concentrated in the first electrode 2, and further improving the bending resistance of the first electrode 2. The cross section of the hole 11 may be circular, elliptical, rectangular, irregular polygonal, etc. (fig. 5 illustrates that the cross section of the hole 11 is circular), which is not limited in this embodiment.

Compared with the first embodiment or the second embodiment, in the present embodiment, by providing at least one hole on the first conductive layer a or the second conductive layer B and releasing the stress when the flexible display panel is bent through the hole, the stress can be further prevented from being concentrated in the first electrode and/or the second electrode 8, which is beneficial to further improving the bending resistance of the first electrode.

A fourth embodiment of the present invention relates to a display device.

As shown in fig. 6, the display device includes a flexible display screen according to the first embodiment, the second embodiment, or the third embodiment. The flexible display device may be a portable mobile terminal such as a mobile phone and a tablet computer, or may be another terminal that selects the flexible display screen of the first embodiment or the second embodiment, which is not limited in this embodiment.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

Claims

1. A flexible display screen, comprising: the light-emitting unit comprises a first electrode, a second electrode and a light-emitting layer arranged between the first electrode and the second electrode;

the first electrode and/or the second electrode comprise: the conductive connecting block is connected between the first conductive layer and the second conductive layer; the sum of the projection areas of all the conductive connection blocks on the first conductive layer is smaller than the area of the first conductive layer, and the sum of the projection areas of all the conductive connection blocks on the second conductive layer is smaller than the area of the second conductive layer;

wherein the width of the first conductive layer and the width of the second conductive layer are 200-300 times of the height of the conductive connection block.

2. The flexible display screen of claim 1, wherein the elastic modulus of the first conductive layer and the elastic modulus of the second conductive layer are less than the elastic modulus of the conductive connection block.

3. The flexible display screen of claim 1, wherein the height of the first electrode and/or the second electrode is 140 nm and 200 nm.

4. The flexible display screen of claim 1, wherein the height of the conductive connection block is 100 nm and 150 nm.

5. The flexible display screen of claim 1, wherein each first electrode and/or each second electrode comprises a plurality of the conductive connection blocks, the plurality of conductive connection blocks being spaced between the first conductive layer and the second conductive layer.

6. The flexible display screen of claim 5, wherein the plurality of conductive connection blocks are equally spaced.

7. A flexible display screen according to claim 5 or 6, wherein the distance between two adjacent conductive connection blocks is 15-20 μm.

8. The flexible display screen of claim 1 or 2, wherein a buffer for absorbing stress is arranged in a gap between the first conductive layer and the second conductive layer, and an elastic modulus of the buffer is smaller than an elastic modulus of the first conductive layer and an elastic modulus of the second conductive layer.

9. The flexible display screen of claim 8, wherein the first conductive layer or the second conductive layer is provided with at least one hole for stress relief.

10. A display device, characterized in that it comprises a flexible display screen according to any one of claims 1 to 9.