CN113594208A

CN113594208A - Flexible display device

Info

Publication number: CN113594208A
Application number: CN202110772611.8A
Authority: CN
Inventors: 祝翠林
Original assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2021-11-02

Abstract

A flexible display device comprises a display substrate, a heat dissipation composite material and an anti-extrusion material, wherein the display substrate comprises a display area, a non-display area and a bending portion, the non-display area surrounds the display area, and the bending portion extends from the non-display area and bends towards the bottom direction of the display substrate. The heat dissipation composite material is arranged on the surface of one side of the display substrate and comprises grid glue and copper foil which are sequentially stacked. The anti-extrusion material is arranged on one side face, far away from the display substrate, of the heat dissipation composite material, the projection area of the anti-extrusion material on the display substrate partially covers the display area and the non-display area, the capability of the heat dissipation composite material for resisting extrusion deformation is improved, and the occurrence of marks caused by the deformation of copper foil is avoided, so that the appearance quality of products is improved, and the yield and the price competitiveness of the products are improved.

Description

Flexible display device

Technical Field

The invention relates to the technical field of display, in particular to a flexible display device for increasing the resistance of a product to extrusion deformation.

Background

In the modern communication industry, the market demands of products such as mobile phones, televisions, flat panels, notebooks, digital cameras and the like are increasing, various display devices are developing in a bendable manner, and the product materials are designed towards a larger area and a thinner thickness direction. In the manufacture of flexible mobile phone display modules, customers have increasingly stringent requirements on the appearance and taste of products. In the structure of the existing product, the copper foil is adopted in the composite material for back heat dissipation, the copper foil is easy to deform, and the deformation of the extruded copper foil can be displayed as a mark on the front surface, so that the appearance is poor. In the module manufacturing process, material handling, material bonding, bending (bonding) pressing and the like all cause the composite material to deform by extrusion, wherein the bending pressing is the most frequent and serious process of impression, and needs to be improved urgently.

Disclosure of Invention

The invention aims to provide a flexible display device, which can increase the capability of a heat dissipation composite material for resisting extrusion deformation and avoid the occurrence of marks caused by the deformation of a copper foil, thereby improving the appearance quality of a product, and improving the yield and price competitiveness of the product.

In order to achieve the above object, the present invention provides a flexible display device including a display substrate, a heat dissipation composite, and an anti-extrusion material, wherein the display substrate includes a display region, a non-display region surrounding the display region, and a bending portion extending from the non-display region and bending toward a bottom of the display substrate. The heat dissipation composite material is arranged on the surface of one side of the display substrate and comprises grid glue, foam, polyimide and copper foil which are sequentially stacked. The anti-extrusion material is arranged on one side face, far away from the display substrate, of the heat dissipation composite material, and the projection area of the anti-extrusion material on the display substrate partially covers the display area and the non-display area.

Preferably, the anti-extrusion material comprises one of stainless steel, nickel and chromium or a combination thereof.

Preferably, the anti-extrusion material is arranged on one side surface of the polyimide far away from the foam and partially corresponds to the display area and the non-display area, and the anti-extrusion material is adjacent to the copper foil and arranged in the same layer.

Preferably, the anti-extrusion material is arranged on the surface of one side of the copper foil, which is far away from the polyimide, and is arranged corresponding to the display area and the non-display area.

Preferably, the heat dissipating composite further comprises a graphite sheet disposed between the polyimide and the copper foil.

Preferably, the display device further comprises a first flexible substrate disposed at the bending portion, and a control board and a second flexible substrate disposed behind the display substrate, wherein two ends of the first flexible substrate are electrically connected to the display substrate and the control board, respectively.

Preferably, one end of the second flexible substrate is electrically connected to the control board and is attached to one side surface of the anti-extrusion material in the direction of the display area.

Preferably, the display device further comprises a driving integrated circuit electrically connected to the control board or the second flexible substrate, the driving integrated circuit providing signals to the plurality of pixels of the display substrate.

Preferably, the flexible display device further includes a first polyester, a polarizing film, an optical adhesive, and a glass cover plate, wherein the first polyester is disposed between the display substrate and the heat dissipation composite material, and the polarizing film, the optical adhesive, and the glass cover plate are sequentially stacked on a surface of the display substrate on a side away from the first polyester.

Preferably, the heat dissipation composite material further comprises a reinforcing plate and a second polyester, wherein the reinforcing plate is arranged on one side face, away from the heat dissipation composite material, of the anti-extrusion material, and the second polyester is arranged on one side face, away from the anti-extrusion material, of the reinforcing plate.

The invention also has the following effects that aiming at the problem of copper foil bending marks, the anti-extrusion material is provided in the bending pressing area, so that the capability of the heat dissipation composite material for resisting extrusion deformation is increased, and the marks caused by the deformation of the copper foil are avoided, thereby improving the appearance quality of the flexible display device and improving the yield and price competitiveness of the flexible display device. Moreover, the heat dissipation composite material is still including setting up the graphite flake, and when carrying out the pressfitting in-process, the graphite flake can increase the effect to the anti extrusion in heat dissipation composite material back or hot pressing resistance, and then promotes flexible display device quality more.

Drawings

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

FIG. 1 is a schematic cross-sectional view of a flexible display device of the present invention;

FIG. 2 is another schematic view of a cross-section of a flexible display device according to the invention; and

fig. 3 is a schematic cross-sectional view of a heat dissipating composite of the present invention provided with a graphite sheet.

Detailed Description

Reference in the detailed description to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the same phrases in various places in the specification are not necessarily limited to the same embodiment, but are to be construed as independent or alternative embodiments to other embodiments. In light of the disclosure of the embodiments provided by the present invention, it should be understood by those skilled in the art that the embodiments described in the present invention can have other combinations or variations consistent with the concept of the present invention.

Fig. 1 is a schematic cross-sectional view of a flexible display device. As shown, the present invention provides a flexible display device 100, which includes a display substrate 110, a heat dissipation composite 120, and an anti-extrusion material 130. The display substrate 110 includes a display region 112, a non-display region 114, and a bending portion 116, the non-display region 114 surrounds the display region 112, and the bending portion 116 extends from the non-display region 114 and is bent toward a bottom direction of the display substrate 110. The heat dissipation composite 120 is disposed on a side surface of the display substrate 110, and the heat dissipation composite 120 includes a grid adhesive 122, a foam 124, a Polyimide (PI) 126, and a copper foil 128, which are sequentially stacked. The anti-extrusion material 130 is disposed on a side of the heat dissipation composite material 120 away from the display substrate 110, and a projection area of the anti-extrusion material 130 on the display substrate 110 partially covers the display area 112 and the non-display area 114.

In this embodiment, the anti-extrusion material 130 is preferably Stainless Steel (SS) or an alloy thereof, which can increase the anti-extrusion deformation capability of the heat dissipation composite material 120 and avoid the occurrence of marks caused by the deformation of the copper foil 128, thereby improving the appearance quality of the product, the yield of the product, and the price competitiveness of the product. In other different embodiments, the anti-extrusion material 130 may also be selected from one of nickel and chromium, or a combination thereof, and is not limited.

In the embodiment shown in fig. 1, the anti-extrusion material 130 is disposed on a side surface of the polyimide 126 away from the foam 124 and partially corresponds to the display area 112 and the non-display area 114, wherein the anti-extrusion material 130 is adjacent to and layered with the copper foil 128. Thus, the anti-extrusion capability of the heat dissipation composite material 120 can be effectively increased while avoiding increasing the thickness of the entire flexible display device 100. However, in the embodiment shown in fig. 2, the anti-extrusion material 130 is disposed on a side surface of the copper foil 128 away from the polyimide 126 and is disposed corresponding to the display area 112 and the non-display area 114, such that the anti-extrusion material is directly attached to the side surface of the copper foil 128, which can rapidly increase the anti-extrusion capability of the heat dissipation composite material 120.

In the embodiment shown in fig. 2, the length of the anti-extrusion material 130 generally corresponds to the area of the pressing devices a and B, such as pressing tools such as a pressing head, for adhering/pressing the anti-extrusion material 130 and other materials together.

Specifically, the display region 112 of the display substrate 110 includes a plurality of scan lines, a plurality of data lines, a plurality of driving power lines, a plurality of pixels, and an organic light emitting layer (not shown). The plurality of scan lines are arranged at certain intervals to cross the plurality of data lines, and the plurality of driving power lines are arranged in parallel with the plurality of scan lines or the plurality of data lines. The plurality of pixels are respectively formed in a plurality of pixel regions defined by intersections between a plurality of scan lines and a plurality of data lines, and display an image according to scan signals from the scan lines and data signals from the respective data lines.

Each pixel driving circuit (not shown) includes a switching transistor connected to a corresponding scanning line and data line, a driving transistor connected to the switching transistor, and a capacitor connected to a gate and a source of the driving transistor. Each pixel driving circuit supplies a data signal to the driving transistor (the data signal is supplied to the corresponding data line through the switching transistor turned on according to a scan signal supplied from the corresponding scan line) to store a gate-source voltage of the driving transistor corresponding to the data signal in the capacitor.

Each driving transistor (not shown) is turned on by the voltage stored in the capacitor and supplies a data current corresponding to the data signal to the organic light emitting element. In this embodiment, each transistor may be an amorphous silicon Thin Film Transistor (TFT), a polysilicon TFT, an oxide TFT, or an organic TFT. Each pixel driving circuit may further include at least one compensation transistor and at least one compensation capacitor for compensating for a threshold voltage of the driving transistor.

Each organic light emitting element (not shown) includes a pixel electrode (or anode) connected to the driving transistor, an organic light emitting layer formed on the pixel electrode, and a cathode formed on the organic light emitting layer. Each organic light emitting element emits light using a data current flowing from the pixel electrode to the cathode according to the turned-on driving transistor, and provides luminance corresponding to the data current onto the display substrate 110.

Referring also to fig. 3, the heat dissipation composite 120 further includes a graphite sheet 129 and a plurality of Pressure Sensitive Adhesives (PSAs) 121, wherein the graphite sheet 129 is preferably disposed between the polyimide 126 and the copper foil 128, which can increase the anti-pressing or anti-hot-pressing effect on the back surface of the heat dissipation composite 120. In this embodiment, each of the pressure sensing adhesives 121 is attached to two opposite surfaces of the polyimide 126 and one surface of the copper foil 128 facing the graphite sheet 129, so that the foam 124, the polyimide 126, the graphite sheet 129, and the copper foil 128 are fixedly laminated with each other. It should be noted that the heat dissipation Composite 120 is also referred to as a Super Composite Film (SCF), which can increase the heat dissipation or other suitable effects of the flexible display device 100.

The flexible display device 100 further includes a first flexible substrate 140 disposed on the bending portion 116, and a control board 142 and a second flexible substrate 144 disposed behind the display substrate 110. Two ends of the first flexible substrate 140 are electrically connected to the display substrate 110 and the control board 142, respectively, and one end of the second flexible substrate 144 is electrically connected to the control board 142 and is attached to one side of the anti-squeezing material 130 toward the display area 112. In the embodiment shown in fig. 1 and 2, the device further comprises a driving ic 146 electrically connected to the control board 142 or the second flexible substrate 144, wherein the second flexible substrate 144 is further attached to a side of the anti-extrusion material 130 by, for example, a glue 162. The driving integrated circuit 146 provides a display signal to a plurality of pixels of the display substrate 110.

In addition, in this embodiment, the flexible display device 100 further includes a first polyester (PET resin) 150, a polarizing film 152, an optical adhesive 154, a glass cover plate 156, and the like. The first polyester 150 is disposed between the display substrate 110 and the heat dissipation composite 120, and the polarizing film 152, the optical adhesive 154 and the glass cover plate 156 are sequentially stacked on a surface of the display substrate 110 away from the first polyester 150.

In the embodiment shown in fig. 2, the flexible display device 100 further includes a reinforcing plate 160 disposed on a side of the anti-extrusion material 130 away from the heat dissipation composite material 120, and a second polyester 158 disposed on a side of the reinforcing plate 160 away from the anti-extrusion material 130.

When the first flexible substrate 140, the control board 142 and the second flexible substrate 144 are bent to the back of the display device 100, the first flexible substrate 140, the control board 142 and/or the second flexible substrate 144 are pressed at a local area and positioned on the back of the flexible display device 100. Since the first flexible substrate 140 is flexible and is easily damaged or broken when it is subjected to a bonding stress such as the bonding devices a and B, it is necessary to obtain an external support through a stiffening plate (Stiffener)160 and/or a second polyester 158, and the material used for the stiffening plate 160 is, for example, PI, polyester (polyester), glass fiber, polymer material, aluminum sheet or steel sheet. In particular, it is greatly helpful to avoid tearing of the flexible substrate by properly designing the position or material of the reinforcing plate 160.

The display substrate 110 in this embodiment is, for example, an Organic Light Emitting Display (OLED). The flexible display device 100 can be applied to flexible OLED display and lighting devices of wearable devices such as smart bracelets, smart watches, Virtual Reality (VR) devices, mobile phones, electronic books/newspapers, televisions, personal portable computers, foldable/rollable OLEDs, and the like.

The problem of this embodiment to the copper foil 128 impression of buckling through providing an anti extrusion material 130 in the pressfitting region of buckling, increases the ability that the compound material 120 of heat dissipation resisted the extrusion deformation, avoids taking place because of the impression that the copper foil 128 warp and leads to promote flexible display device 100 outward appearance quality, promote flexible display device 100 yield and price competitiveness. Moreover, the heat dissipation composite material 120 further includes a graphite sheet 129, and in the pressing process, the graphite sheet 129 can increase the anti-extrusion or anti-hot-pressing effect on the back surface of the heat dissipation composite material 120, so as to further improve the quality of the flexible display device 100.

In view of the foregoing, while the present invention has been described in conjunction with specific embodiments thereof, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the included claims.

Claims

1. A flexible display device, comprising:

a display substrate including a display region, a non-display region surrounding the display region, and a bent portion extending from the non-display region and bent toward a bottom direction of the display substrate;

the heat dissipation composite material is arranged on the surface of one side of the display substrate and comprises grid glue, foam, polyimide and copper foil which are sequentially stacked; and

and the anti-extrusion material is arranged on one side surface of the heat dissipation composite material, which is far away from the display substrate, and the projection area of the anti-extrusion material on the display substrate partially covers the display area and the non-display area.

2. The flexible display device of claim 1, wherein the anti-extrusion material comprises one of stainless steel, nickel, chrome, or a combination thereof.

3. The flexible display device as claimed in claim 1, wherein the anti-extrusion material is disposed on a side surface of the polyimide remote from the foam and partially corresponds to the display area and the non-display area, and the anti-extrusion material is disposed adjacent to and in the same layer as the copper foil.

4. The flexible display device according to claim 1, wherein the anti-extrusion material is disposed on a surface of the copper foil on a side away from the polyimide and corresponding to the display region and the non-display region.

5. The flexible display device of claim 1, wherein the heat spreading composite further comprises a graphite sheet disposed between the polyimide and the copper foil.

6. The flexible display device according to claim 1, further comprising a first flexible substrate disposed at the bending portion, and a control board and a second flexible substrate disposed behind the display substrate, wherein both ends of the first flexible substrate are electrically connected to the display substrate and the control board, respectively.

7. The flexible display device as claimed in claim 6, wherein one end of the second flexible substrate is electrically connected to the control board and attached to a side surface of the anti-extrusion material toward the display area.

8. The flexible display device of claim 6, further comprising a driver integrated circuit electrically connected to the control board or the second flexible substrate, the driver integrated circuit providing signals to a plurality of pixels of the display substrate.

9. The flexible display device according to claim 1, further comprising a first polyester, a polarizer film, an optical adhesive and a glass cover plate, wherein the first polyester is disposed between the display substrate and the heat dissipation composite, and the polarizer film, the optical adhesive and the glass cover plate are sequentially stacked on a surface of the display substrate away from the first polyester.

10. The flexible display device according to claim 9, further comprising a stiffener disposed on a side of the anti-extrusion material remote from the heat dissipation composite and a second polyester disposed on a side of the stiffener remote from the anti-extrusion material.