Patent Publication Number: US-2023157131-A1

Title: Flexible display panel and flexible display device

Description:
FIELD OF INVENTION 
     The present application relates to the field of display technologies, and in particular to a flexible display panel and a flexible display device. 
     BACKGROUND OF INVENTION 
     Development trend of intelligence, portability, and flexibility is one of the main development directions of current electronic equipment. New display devices represented by organic light-emitting diodes (OLEDs) have received more and more attention and recognition due to their outstanding features such as lightweightness and thinness, vividness, energy-saving, and flexibility. Among them, foldable displays, as a development direction of a new generation of flexible display technology, have received extensive attention in the industry. 
     However, in order to facilitate consumers to have a better handfeel when holding a display device or sliding a screen, current high-end products are designed with curved surfaces, and a shape of a current foldable flexible display device is relatively square and monotonous. Consumers have a less satisfactory handfeel when holding the flexible display device or sliding the screen, and how to realize the curved surface design of the foldable flexible display device has become an urgent problem in this field. 
     SUMMARY OF INVENTION 
     Technical Problem 
     At present, the shape of the foldable flexible display device is relatively square and monotonous, and it is difficult to realize the curved surface design of the foldable flexible display device. 
     Technical Solutions 
     In a first aspect, the present application provides a flexible display panel, the flexible display panel including: 
     a flexible display screen including a first bending region and a second bending region positioned on two opposite sides of the first bending region, wherein the second bending region is positioned at an edge of the flexible display screen; and 
     a support disposed on a backside of the flexible display screen and connected to the flexible display screen, wherein the support includes a first folding portion corresponding to the first bending region and a hollowed-out structure corresponding to the second bending region. 
     In some embodiments, a first grid-structure is provided at the first folding portion. 
     In some embodiments, the hollowed-out structure includes a second folding portion corresponding to the second bending region and a second grid-structure provided at the second folding portion, and the second folding portion is positioned at an edge of the support. 
     In some embodiments, the second grid-structure extends to an edge of the second folding portion in a direction away from the first folding portion. 
     In some embodiments, a distance between the edge of the second folding portion away from the first folding portion and the second grid-structure is greater than zero. 
     In some embodiments, a grid density of the second grid-structure is less than a grid density of the first grid-structure. 
     In some embodiments, the support includes a first surface close to the flexible display screen and a second surface away from the flexible display screen, and a first grid-hole of the first grid-structure and a second grid-hole of the second grid-structure both connect the first surface to the second surface. 
     In some embodiments, the first grid-hole and the second grid-hole are filled with a buffer material. 
     In some embodiments, a bending axis of the first bending region is parallel to a bending axis of the second bending region. 
     In a second aspect, the present application further provides a flexible display device, the flexible display device including a middle frame module and a flexible display panel, wherein the flexible display panel includes: 
     a flexible display screen including a first bending region and a second bending region positioned on two opposite sides of the first bending region, wherein the second bending region is positioned at an edge of the flexible display screen; and 
     a support disposed on a backside of the flexible display screen and connected to the flexible display screen, wherein the support includes a first folding portion corresponding to the first bending region and a hollowed-out structure corresponding to the second bending region. 
     In some embodiments, a first grid-structure is provided at the first folding portion. 
     In some embodiments, the hollowed-out structure includes a second folding portion corresponding to the second bending region and a second grid-structure provided at the second folding portion, and the second folding portion is positioned at an edge of the support. 
     In some embodiments, the second grid-structure extends to an edge of the second folding portion in a direction away from the first folding portion. 
     In some embodiments, a distance between the edge of the second folding portion away from the first folding portion and the second grid-structure is greater than zero. 
     In some embodiments, a grid density of the second grid-structure is less than a grid density of the first grid-structure. 
     In some embodiments, the support includes a first surface close to the flexible display screen and a second surface away from the flexible display screen, and a first grid-hole of the first grid-structure and a second grid-hole of the second grid-structure both connect the first surface to the second surface. 
     In some embodiments, the first grid-hole and the second grid-hole are filled with a buffer material. 
     In some embodiments, a bending axis of the first bending region is parallel to a bending axis of the second bending region. 
     Wherein, the middle frame module is positioned on a backside of the flexible display panel and is connected to the flexible display panel, the middle frame module includes a folding region corresponding to the first bending region, a portion of the flexible display screen positioned in the second bending region is bent to the backside of the flexible display screen to form a first curved portion, and the middle frame module further includes a second curved portion corresponding to the first curved portion. 
     Beneficial Effect 
     The first bending region of the flexible display screen can be bent, and an edge portion of the flexible display screen can also be bent. At the same time, the support is configured to support the flexible display screen, and the support has the hollowed-out structure positioned corresponding to the second bending region, so that while the flexible display panel has a folding function, a curved structure with a specific curvature can be formed at the edge of the flexible display panel. Therefore, the flexible display screen can be used to form a foldable flexible display device with a curved surface. When the consumer holds the flexible display device, a palm of a hand touches the curved surface of the edge of the flexible display screen, which can improve a handfeel of consumers, and at the same time facilitate consumers to slide and operate the flexible display screen. 
    
    
     
       BRIEF DESCRIPTION OF FIGURES 
       The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application obvious. 
         FIG.  1    is a schematic structural diagram of a flexible display panel according to a first embodiment of the present application. 
         FIG.  2    is a schematic structural diagram of a support according to the first embodiment of the present application. 
         FIG.  3    is another schematic structural diagram of the flexible display panel according to the first embodiment of the present application. 
         FIG.  4    is a schematic structural diagram of a flexible display panel according to a second embodiment of the present application. 
         FIG.  5    is a schematic structural diagram of the support according to the second embodiment of the present application. 
         FIG.  6    is a schematic structural diagram of a flexible display panel according to a third embodiment of the present application. 
         FIG.  7    is a schematic structural diagram of a flexible display device according to an embodiment of the present application. 
         FIG.  8    is another schematic structural diagram of the flexible display device according to an embodiment of the present application. 
         FIG.  9    is yet another schematic structural diagram of the flexible display device according to an embodiment of the present application. 
     
    
    
     REFERENCE SIGNS 
       10 , flexible display screen;  11 , first bending region;  12 , second bending region;  13 , non-bending region;  14 , flexible substrate;  15 , flexible screen;  16 , flexible polarizer;  17 , flexible encapsulation cover plate;  18 , first curved portion;  20 , support;  21 , first folding portion;  22 , second folding portion;  23 , non-folding portion;  24 , first grid-structure;  241 , first grid-hole;  25 , second grid-structure;  251 , second grid-hole;  30 , buffer layer;  40 , optical adhesive layer;  50 , light-shielding layer;  60 , middle frame module;  61 , folding region;  62 , second curved portion;  63 , first portion;  64 , second portion; and  65 , hinge. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The following description of each embodiment, with reference to the accompanying drawings, is used to exemplify specific embodiments which may be carried out in the present invention. Directional terms mentioned in the present invention, such as “top”, “bottom”, “front”, “back”, “left”, “right”, “inside”, “outside”, “side”, etc., are only used with reference to the orientation of the accompanying drawings. Therefore, the used directional terms are intended to illustrate, but not to limit, the present invention. In the drawings, components having similar structures are denoted by the same numerals. 
     The present application addresses a technical problem that a shape of current flexible display devices is relatively square and monotonous, and consumers have a less satisfactory handfeel when holding the flexible display devices. 
     First Embodiment 
     The present application provides a flexible display panel, as shown in  FIG.  1   , wherein the flexible display panel includes a flexible display screen  10  and a support  20 . The support  20  is disposed on a backside of the flexible display screen  10  and is connected to the flexible display screen  10 , and is configured to support the flexible display screen  10  to prevent the flexible display screen  10  from sinking or deforming during a process of operating the flexible display panel. 
     Wherein, the flexible display panel is a foldable flexible display panel, the flexible display screen  10  can be a flexible organic light-emitting diode (OLED) display screen; preparation material of the support  20  can be a material with greater strength, plasticity, and strong bending resistance, including but not limited to metal materials such as steel, copper, iron, aluminum, copper alloy, iron alloy, and aluminum alloy, and acrylic or poly non-metallic materials such as carbonate. 
     Specifically, the flexible display screen  10  includes a first bending region  11 , and the support  20  includes a first folding portion  21  corresponding to the first bending region  11 . 
     It can be understood that the first bending region  11  defines the flexible display screen  10  into two portions positioned on both sides of the first bending region  11 . When the flexible display panel is folded, the flexible display screen  10  is folded along the first bending region  11 , at the same time, the support  20  is synchronously folded with the flexible display screen  10  along the first folding portion  21 , and the support  20  supports the flexible display screen  10  during a folding process of the flexible display screen  10 . 
     Specifically, the flexible display screen  10  can be attached to the support  20 , and the first bending region  11  can be positioned in a middle region of the flexible display screen  10 . 
     Wherein, the first folding portion  21  and the flexible display screen  10  can be fixedly connected by a hinge or the like. The first folding portion  21  and the flexible display screen  10  can also be separated, that is, a portion of the flexible display screen  10  positioned at the first bending region  11  is detachably disposed on the first folding portion  21 . 
     Specifically, the flexible display screen  10  further includes a non-bending region  13  positioned on both sides of the first bending region  11 , and the support  20  further includes a non-folding portion  23  corresponding to the non-bending region  13 . The portion of the flexible display screen  10  positioned in the non-bending region  13  and the non-folding portion  23  can be fixedly connected by the hinge or the like. 
     It can be understood that the non-folding portion  23  of the support  20  cannot be bent, and the non-folding portion  23  is configured to support the portion of the flexible display screen  10  positioned in the non-bending region  13 . Therefore, the portion of the flexible display screen  10  positioned in the non-bending region  13  cannot be bent, so as to prevent the portion of the flexible display screen  10  positioned in the non-bending region  13  from being folded or deformed during the folding process of the flexible display screen  10 . 
     As shown in  FIG.  1    and  FIG.  2   , a first grid-structure  24  can be provided at the first folding portion  21 , and the first grid-structure  24  can be formed on the first folding portion  21  by means of laser etching or chemical etching. The first grid-structure  24  is configured to improve the stretching and elongation properties of the first folding portion  21 , thereby greatly enhancing a bending performance of the first folding portion  21 . 
     Specifically, the flexible display screen  10  further includes a second bending region  12  positioned on two opposite sides of the first bending region  11 , and the second bending region  12  is positioned at an edge of the flexible display screen  10 , that is, the second bending region  12  is an edge region of the flexible display screen  10 . The support  20  further includes a hollowed-out structure corresponding to the second bending region  12 . 
     It can be understood that the non-bending region  13  of the flexible display screen  10  is a portion of the flexible display screen  10  excluding the first bending region  11  and the second bending region  12 . 
     It should be noted that the first bending region  11  of the flexible display screen  10  in the present application can be bent, and a portion of the flexible display screen positioned in the second bending region  12  can also be bent. At the same time, the support is configured to support the flexible display screen  10 , and the support  20  has the hollowed-out structure positioned corresponding to the second bending region  12 , so that while the flexible display panel has a folding function, a curved structure with a specific curvature can be formed at the edge of the flexible display panel. Therefore, the flexible display screen can be used to form a foldable flexible display device with a curved surface. When the consumer holds the flexible display device, a palm of a hand touches the curved surface of the edge of the flexible display screen, which can improve a handfeel of consumers, and at the same time facilitate consumers to slide and operate the flexible display screen. 
     In an embodiment, the hollowed-out structure includes a second folding portion  22  corresponding to the second bending region  12  and a second grid-structure  25  disposed on the second folding portion  22 . The second folding portion  22  is positioned at an edge of the support  20 , that is, the second folding portion  22  is an edge portion of the support  20 . 
     Wherein, the second folding portion  22  and the flexible display screen  10  can be fixedly connected by a hinge or the like, and the second folding portion  22  can also be separated from the flexible display screen  10 , that is, the portion of the flexible display screen  10  positioned in the second bending region  12  is detachably disposed on the second folding portion  22 . 
     Wherein, the first folding portion  21 , the second folding portion  22 , and the non-folding portion  23  can be integrally formed. The first folding portion  21 , the second folding portion  22 , and the non-folding portion  23  can also be separately formed and then assembled by threaded connection, hinge, or snap connection to form the support  20 . The second grid-structure  25  can be formed on the second folding portion  22  by means of laser etching or chemical etching. 
     It should be noted that the hollowed-out structure is a partially hollowed-out structure, when the portion of the flexible display screen  10  positioned in the second bending region is bent to form an edge curved surface, the second folding portion  22  can also be bent to form an arc structure that supports the edge curved surface of the flexible display screen  10 . At the same time, the second grid-structure  25  is configured to improve the stretching and elongation properties of the second folding portion  22 , thereby greatly enhancing a bending performance of the second folding portion  22 . 
     It should be noted that the second grid-structure  25  and the first grid-structure  24  can be formed at the same time in a process, or can be formed through different processes. 
     In an embodiment, a grid density of the second grid-structure  25  is less than a grid density of the first grid-structure  24 . 
     It is understandable that the grid density refers to number of grids in a unit region. The greater the grid density, the greater the number of grids in the unit region and the smaller the grid size. 
     After the flexible display panel is assembled to form a flexible display device, during a use of the flexible display panel, the first folding portion  21  will be folded multiple times. By increasing the grid density of the first grid-structure  24 , therefore, while the first grid-structure  24  is configured to enhance the bending performance of the first folding portion  21 , the strength of the first folding portion  21  is ensured, and the first folding portion  21  is prevented from bend-breaking. 
     After the flexible display panel is assembled to form a flexible display device, the second folding portion  22  is bent to form the arc structure and then remains in the arc structure. There is no need to bend the second folding portion  22 . At this time, by reducing the grid density of the first grid-structure  24 , the bending performance of the second folding portion  22  can be greatly improved, facilitating a formation of the arc structure with a preset size, and improving a processing accuracy. 
     It should be noted that the grid density of the first grid-structure  24  and the second grid-structure  25  can be selected according to the actual conditions of material, area, and thickness of the support  20 . 
     Specifically, the support  20  includes a first surface close to the flexible display screen  10  and a second surface away from the flexible display screen  10 . A first grid-hole  241  of the first grid-structure  24  and a second grid-hole  251  of the second grid-structure  25  both connect the first surface to the second surface to improve the bending performance of the first folding portion  21  and the second folding portion  22 . 
     It is understandable that a cross-sectional shape of the first grid-structure and the second grid-structure can be regular or irregular, including but not limited to bar, rhomboidal, hexagonal, circular, square, elliptical, or arc, etc., and the present application is not limited. 
     In an embodiment, the second grid-structure  25  extends to the edge of the second folding portion  22  in a direction away from the first folding portion  21 . 
     It is understandable that the second folding portion  22  is positioned at the edge of the support  20 , and the edge of the second folding portion  22  is the edge of the support  20 , so that the bending performance of the edge of the second folding portion  22  can be facilitated. The second folding portion  22  is bent to form an arc structure with a predetermined size. 
     In an embodiment, a bending axis of the first bending region  11  is parallel to a bending axis of the second bending region  12 . 
     It can be understood that when the flexible display screen  10  is folded, two portions of the flexible display screen  10  positioned on both sides of the first bending region  11  rotate around the bending axis of the first bending region  11 , and the bending axis of the second bending region  12  refers to an axial direction of a curved structure when the second bending region  12  forms the curved structure. 
     Wherein, the bending axis of the first bending region  11  is parallel to a bending axis of the first folding portion  21 , and the bending axis of the second bending region  12  is parallel to a bending axis of the second folding portion  22 . 
     In an embodiment, a width of the second grid-structure  25  is greater than a width of the first grid-structure  24 . 
     It should be noted that  FIG.  1    and  FIG.  2    only illustrate the case where each of two sides of the flexible display panel can form a curved structure. It is understandable that the flexible display panel can also be configured such that all four sides can form a curved structure. That is, each the second bending region  12  is provided at edges of the four sides of the flexible display panel. 
     It is understandable that the above description only describes an arrangement and connection of the flexible display screen  10  and the support  20 , and the flexible display screen  10  is generally formed by a combination of a multilayer film structure. 
     As shown in  FIG.  3   , in an embodiment, the flexible display screen  10  includes a flexible substrate  14 , a flexible screen body  15  disposed on the flexible substrate  14 , a flexible polarizer  16  disposed on the flexible screen body  15 , and a flexible encapsulation cover plate  17  disposed on the flexible polarizer  16 . 
     Wherein, the support  20  is positioned on a side of the flexible substrate  14  away from the flexible screen body  15 . The flexible substrate  14  is connected to the support  20  through a buffer layer  30 . The flexible encapsulation cover plate  17  is bonded to the flexible polarizer  16  through an optical adhesive layer  40 . The flexible encapsulation cover plate  17  includes, but is not limited to, a transparent glass cover plate or a transparent plastic cover plate. 
     In an embodiment, the flexible encapsulation cover plate  17  is further provided with a light-shielding layer  50  on a side close to the optical adhesive layer  40 , and the light-shielding layer  50  is positioned in the second bending region  12  to prevent an edge from light leakage. The light-shielding layer  50  can be a black ink layer. 
     In an embodiment, the first grid-hole  241  and the second grid-hole  251  are filled with a buffer material, and the buffer material includes, but is not limited to, an elastic material or a foamed porous material to enhance the strength of the first folding portion  21  and the second folding portion  22 , and prevent the first folding portion  21  and the second folding portion  22  from bend-breaking. 
     It should be noted that it is also possible to fill only the first grid-hole  241  or the second grid-hole  251  with the buffer material. 
     Second Embodiment 
     The present application further provides a flexible display panel, which differs from the first embodiment only in an arrangement of the second grid-structure  25 . 
     Specifically, as shown in  FIG.  4    and  FIG.  5   , a distance between the edge of the second folding portion  22  away from the first folding portion  21  and the second grid-structure  25  is greater than zero, that is, an orthographic projection of the edge of the second folding portion  22  away from the first folding portion  21  projected on the flexible display screen  10  and an orthographic projection of the second grid-structure  25  projected on the flexible display screen  10  have no overlap. 
     It is understandable that an edge portion of the second folding portion  22  away from the first folding portion  21  does not have a grid-structure, so that the strength and rigidity of the edge portion of the second folding portion  22  away from the first folding portion  21  can be ensured, and the edge portion of the second folding portion  22  away from the first folding portion  21  is prevented from sinking or deforming during operating. 
     It should be noted that a size of the distance between the edge of the second folding portion  22  away from the first folding portion  21  and the second grid-structure  25  can be selected according to actual conditions. 
     Third Embodiment 
     The present application further provides a flexible display panel, which differs from the first embodiment only in the structure of a hollowed-out structure. 
     Specifically, as shown in  FIG.  6   , an orthographic projection of a support  20  projected on a flexible display screen  10  is in contact with or separated from a first bending region  11 , that is, a distance between the orthographic projection of the support  20  projected on the flexible display screen  10  and the first bending region  11  is greater than or equal to zero, that is, the hollowed-out structure is a complete hollowed-out structure, that is, a portion of the support  20  corresponding to a second bending region  12  is completely hollow in the present embodiment. 
     It can be understood that the portion of the support  20  corresponding to the second bending region  12  is removed, so as to facilitate a bending of a portion of the flexible display screen  10  positioned in the second bending region  12 . 
     Based on the above-mentioned flexible display panel, the present application further provides a flexible display device. As shown in  FIG.  7   , the flexible display device includes a middle frame module  60  and a flexible display panel as described in any of the above-mentioned embodiments. 
     Wherein, the middle frame module  60  is positioned on a backside of the flexible display panel and is connected to the flexible display panel, and the middle frame module  60  includes a folding region  61  corresponding to a first bending region  11 . A portion of the flexible display screen  10  positioned in the second bending region  12  is bent back to form a first curved portion  18 . The middle frame module  60  further includes a second curved portion  62  corresponding to the first curved portion  18 . 
     It should be noted that the middle frame module  60  is configured to support and fix the flexible display panel, and the flexible display panel and the middle frame module  60  can be fixedly connected by a sealant. The middle frame module  60  can include a middle frame and a back shell, and the flexible display device can be a display device such as a mobile phone, a computer display screen, a tablet computer, or a handheld game console. Surfaces of the first curved portion  18  and the second curved portion  62  are both curved, and the surface of the second curved portion  62  matches a bottom surface of the first curved portion  18 . 
     Refer to  FIG.  7   , it can be understood that when the support  20  includes a second folding portion  22 , the second folding portion  22  is bent to a backside to form an arc structure that matches the first curved portion  18 , and the arc structure fits on the second curved portion  62 . 
     Refer to  FIG.  8   , it can be understood that when the support  20  does not include the second folding portion  22 , the first curved portion  18  of the flexible display panel is attached to the second curved portion  62 , and the second curved portion  62  of the middle frame module  60  is configured to support the first curved portion  18 . 
     As shown in  FIG.  7    and  FIG.  8   , in an embodiment, a groove is defined on the middle frame module  60 , and the support  20  is disposed in the groove to reduce an overall thickness of the flexible display device and to make an overall structure of the flexible display device more compact. 
     It is understandable that the middle frame module  60  can be folded along a folding region  61 , and the middle frame module  60  can be folded along the folding region  61  in various ways. 
     In an embodiment, as shown in  FIG.  9   , a hinge  65  is disposed in the folding region  61  of the middle frame module  60 , and a hinge axis of the hinge  65  is in parallel with a bending axis of the first bending region  11 . 
     Wherein, the middle frame module  60  includes a first portion  63  and a second portion  64 . The first portion  63  is fixedly connected to a side wing of the hinge  65 , and the second portion  64  is fixedly connected to another side wing of the hinge  65 , so that the first portion  63  and the second portion  64  can rotate around the hinge axis of the hinge  65 , therefore the middle frame module  60  can be folded along the folding region  61 . 
     It should be noted that the folding region  61  of the middle frame module  60  can also be made of a flexible material, and other portion of the middle frame module  60  is connected to the folding region  61 , so that the middle frame module  60  can be folded along the folding region  61 , therefore the middle frame module  60  can be folded along the folding region  61 . 
     It can be understood that, in actual implementation, the middle frame module  60  can also be folded along the folding region  61  in other ways, which will not be listed here. 
     The beneficial effects of the present application are that the first bending region  11  of the flexible display screen  10  can be bent, the edge portion of the flexible display screen  10  can also be bent, at the same time, the support  20  is configured to support the flexible display screen  10 , and the support  20  is provided with a hollowed-out structure in a region corresponding to the second bending region  12 , so that while the flexible display panel has a folding function, a curved structure with a specific curvature can be formed at the edge of the flexible display panel. Therefore, the flexible display screen can be used to form a foldable flexible display device with a curved surface. When the consumer holds the flexible display device, a palm of a hand touches the curved surface of the edge of the flexible display screen, which can improve a handfeel of consumers, and at the same time facilitate consumers to slide and operate the flexible display screen. 
     In the above-mentioned embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in an embodiment, reference can be made to related descriptions of other embodiments. 
     Specific embodiments are used in the present article to illustrate the principles and implementation of the application. The descriptions of the above embodiments are only used to help understand the technical solutions and core ideas of the application. A person skilled in the art can make various modifications and changes to the above embodiments without departing from the technical idea of the present invention, and such variations and modifications are intended to be within the scope of the invention.