Patent Publication Number: US-2023142422-A1

Title: Display panel

Description:
FIELD OF INVENTION 
     The present disclosure relates to the field of display technology, and more particularly to a display panel. 
     BACKGROUND OF INVENTION 
     In a process of research and practice of the prior art, the inventor of the present disclosure found that with a development of flexible display technology, product sizes have become larger and larger, and consequently sizes of a terminal region of display modules have gradually become larger. However, the larger the size of the terminal region is, the more easily an edge of the terminal region will warp during a bending process, and even cause a metal trace to break. 
     SUMMARY OF INVENTION 
     The embodiment of the present disclosure provides a display panel, which can reduce a risk of warpage of a terminal region and a breakage of a metal trace in the terminal region. 
     The present disclosure provides a display panel, including a display region, a bending region, and a terminal region, wherein the bending region is disposed between the display region and the terminal region, and the display panel further includes: 
     a first backplate disposed in the terminal region; 
     a flexible substrate comprising a first portion disposed in the terminal region, wherein the first portion is disposed on the first backplate; 
     a reinforcement layer, wherein a portion of the reinforcement layer is disposed on the flexible substrate and located in the terminal region; 
     a first protective layer disposed on the first portion, wherein the first protective layer and the reinforcement layer are disposed separately; and 
     a second protective layer disposed on the first protective layer and connected to the reinforcement layer; 
     wherein a boundary of a part of the second protective layer connected to the reinforcement layer is located in the terminal region, and a surface of the reinforcement layer, a surface of the first protective layer and a surface of the second protective layer define a space. 
     Optionally, in some embodiments of the present disclosure, a thickness of the first protective layer is greater than a thickness of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, the thickness of the first protective layer is equal to a thickness of the reinforcement layer. 
     Optionally, in some embodiments of the present disclosure, an elastic modulus of the first protective layer is less than an elastic modulus of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, a thickness of the first protective layer is less than a thickness of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, the first protective layer and the second protective layer are an integrally formed structure. 
     Optionally, in some embodiments of the present disclosure, the display panel further comprises a circuit board disposed on the first portion, the first protective layer is provided with an opening, and the opening penetrates the first protective layer and the second protective layer; and 
     a portion of the circuit board is arranged in the opening. 
     Optionally, in some embodiments of the present disclosure, a distance from the first protective layer to the reinforcement layer is in a range from 0.2 mm to 0.5 mm. 
     Optionally, in some embodiments of the present disclosure, the display panel further including: 
     a transition region connected between the display region and the bending region; 
     a second backplate; and 
     a display portion; 
     wherein the flexible substrate further comprises a second portion and a third portion connected to the first portion in sequence, the second portion is disposed in the transition region and the bending region, and the third portion is disposed in the display region; and 
     wherein the third portion is disposed on the second backplate, the display portion is disposed on the third portion, and the reinforcement layer is disposed on the flexible substrate and extends from the transition region to the terminal region. 
     The present disclosure further providing a display panel including a display region, a bending region, and a terminal region, wherein the bending region is disposed between the display region and the terminal region, and the display panel further comprises: 
     a first backplate disposed in the terminal region; 
     a flexible substrate comprising a first portion disposed in the terminal region, wherein the first portion is disposed on the first backplate; 
     a reinforcement layer, wherein a portion of the reinforcement layer is disposed on the flexible substrate and located in the terminal region; 
     a first protective layer disposed on the first portion, wherein the first protective layer and the reinforcement layer are disposed separately; and 
     a second protective layer disposed on the first protective layer and connected to the reinforcement layer. 
     Optionally, in some embodiments of the present disclosure, a boundary of a part of the second protective layer connected to the reinforcement layer is located in the terminal region. 
     Optionally, in some embodiments of the present disclosure, a thickness of the first protective layer is greater than a thickness of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, the thickness of the first protective layer is equal to a thickness of the reinforcement layer. 
     Optionally, in some embodiments of the present disclosure, an elastic modulus of the first protective layer is less than an elastic modulus of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, a thickness of the first protective layer is less than a thickness of the second protective layer. 
     Optionally, in some embodiments of the present disclosure, a surface of the reinforcement layer, a surface of the first protective layer and a surface of the second protective layer define a space. 
     Optionally, in some embodiments of the present disclosure, the first protective layer and the second protective layer are an integrally formed structure. 
     Optionally, in some embodiments of the present disclosure, the display panel further comprises a circuit board disposed on the first portion, the first protective layer is provided with an opening, and the opening penetrates the first protective layer and the second protective layer; and 
     a portion of the circuit board is arranged in the opening. 
     Optionally, in some embodiments of the present disclosure, a distance from the first protective layer to the reinforcement layer is in a range from 0.2 mm to 0.5 mm. 
     Optionally, in some embodiments of the present disclosure, the display panel further including a transition region connected between the display region and the bending region; 
     a second backplate; and 
     a display portion; 
     wherein the flexible substrate further comprises a second portion and a third portion connected to the first portion in sequence, the second portion is disposed in the transition region and the bending region, and the third portion is disposed in the display region; and 
     wherein the third portion is disposed on the second backplate, the display portion is disposed on the third portion, and the reinforcement layer is disposed on the flexible substrate and extends from the transition region to the terminal region. 
     In the terminal region of the display panel of the embodiment of the present disclosure, the first protective layer and the second protective layer are disposed on the flexible substrate, and the second protective layer is connected with the reinforcement layer to reduce a warpage of the terminal area and a risk of breaking the metal trace on the flexible substrate. 
    
    
     
       DESCRIPTION OF FIGURES 
       In order to more clearly describe the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the figures needed in the description of the embodiments. Obviously, the figures in the following description are only some embodiments of the present disclosure. For those skilled in the art, without inventive steps, other figures can be obtained based on these figures. 
         FIG.  1    is a schematic top view of a structure of a display panel provided by one embodiment of the present disclosure. 
         FIG.  2    is a schematic structural diagram of the display panel in a flat state provided in one embodiment of the present disclosure. 
         FIG.  3    is an enlarged view of portion Q in  FIG.  2   . 
         FIG.  4    is a schematic structural diagram of the display panel in a bent state according to one embodiment of the present disclosure. 
     
    
    
     It should be noted that  FIG.  2    is also a schematic cross-sectional structure view along a line AA′ in  FIG.  1   . 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the figures in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without inventive steps fall within the protection scope of the present disclosure. In addition, it should be understood that the specific embodiments described here are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure. In the present disclosure, unless otherwise stated, the directional words used such as “upper” and “lower” generally refer to an upper direction and a lower direction of the device in actual use or operating state, and specifically refer to a direction in the figures; and “an inner” and “an outer” refer to an outline of the device. 
     The embodiment of the present disclosure provides a display panel, which will be described in detail below. It should be noted that the display panel of this embodiment may be an organic light emitting diode (OLED) display panel, a quantum dot light emitting diode (QLED) display panel, and the like. The display panel of the embodiment of the present disclosure may also be a mini-LED display panel or a micro-LED display panel. In this embodiment, the display panel is the OLED display panel as an example for description, but it is not limited to this. 
     Please refer to  FIGS.  1  to  4   ,  FIG.  1    is a schematic top view of a structure of a display panel provided by one embodiment of the present disclosure;  FIG.  2    is a schematic structural diagram of the display panel in a flat state provided in one embodiment of the present disclosure;  FIG.  3    is an enlarged view of portion Q in  FIG.  2   ;  FIG.  4    is a schematic structural diagram of the display panel in a bent state according to one embodiment of the present disclosure. 
     One embodiment of the present disclosure provides a display panel  100 , which includes a display region AA, a transition region GD, a bending region BD, and a terminal region PD that are sequentially connected. The bending region BD is disposed between the display region AA and the terminal region PD. The display panel  100  includes a first backplate  11 , a second backplate  12 , a flexible substrate  13 , a metal trace  14 , an insulating layer  15 , a display portion  16 , a reinforcement layer  17 , a first protective layer  18 , a second protective layer  19 , and a circuit board  110 . The flexible substrate  13  includes a first portion  131 , a second portion  132 , and a third portion  133  that are connected in sequence. The first portion  131  is disposed in the terminal region PD. The second portion  132  is disposed in the bending region BD and the transition region GD. The third portion  133  is disposed in the display region AA. Among them, the first portion  131 , the second portion  132 , and the third portion  133  may be an integrally formed structure. 
     In the display region AA of the display panel  100 , the second backplate  12 , the third portion  133  of the flexible substrate  13 , and the display portion  16  are stacked in sequence. The display portion  16  includes a driving circuit structure layer, a light emitting device layer, and an encapsulation layer, wherein the driving circuit structure layer includes a thin film transistor, the light emitting device layer includes an anode, a light emitting layer, and a cathode. Since the driving circuit structure layer and the light emitting device layer are in the prior art, they will not be repeated here. 
     In the transition region GD of the display panel  100 , the second portion  132  of the flexible substrate  13 , the metal trace  14 , the insulating layer  15 , and the reinforcement layer  17  on the second backplate  12  are stacked in sequence. The metal trace  14  is electrically connected to the display portion  16  and the circuit board  110 . 
     In the bending region BD of the display panel  100 , the second portion  132  of the flexible substrate  13 , the metal trace  14 , the insulating layer  15 , and the reinforcement layer  17  are stacked in sequence. The metal trace  14  is electrically connected to the display portion  16  and the circuit board  110 . 
     In the terminal region PD of the display panel  100 , the first backplate  11 , the first portion  131  of the flexible substrate  13 , a portion of the metal wiring  14 , a portion of the insulating layer  15 , the first protective layer  18 , and the second protective layer  19  are stacked in this order. In addition, the circuit board  110  is also arranged on the flexible substrate  13 ; specifically, the circuit board  110  is arranged on the insulating layer  15 . A portion of the reinforcement layer  17  is provided on the insulating layer  15 . The insulating layer  15  is provided with an opening  151  that exposes the conductive pad, so that the circuit board  110  is electrically connected to the conductive pad. The conductive pad is electrically connected to the metal trace  14 . 
     Specifically, the first backplate  11  is disposed in the terminal region PD. The flexible substrate  13  includes a first portion  131  disposed in the terminal region PD. The first portion  131  is disposed on the first backplate  11 . 
     The reinforcement layer  17  is disposed on the flexible substrate  13  and located in the terminal region PD. 
     The first protective layer  18  is disposed on the first portion  131 . The first protective layer  18  and the reinforcement layer  17  are arranged separately. The second protective layer  19  is disposed on the first protective layer  18 . The second protective layer  19  is connected to the reinforcement layer  17 . 
     In the terminal region PD of the display panel  100  of the embodiment of the present disclosure, by providing the first protective layer  18  and the second protective layer  19  on the flexible substrate  13  and connecting the second protective layer  19  to the reinforcement layer  17 , a warpage of the terminal region PD and a risk of breaking the metal trace  14  on the flexible substrate  13  are reduced. 
     Specifically, the first protective layer  18  and the second protective layer  19  are disposed on the flexible substrate  13  to improve a stiffness of the display panel  100  in the terminal region PD, thereby reducing the risk of warping of the display panel  100  in the terminal section PD, and at the same time it also plays a role in protecting the metal trace  14 . 
     Optionally, the elastic modulus of the first protective layer  18  and the second protective layer  19  are both greater than the elastic module of the first backplate  11 , so as to suppress a warpage of the first backplate  11 , thereby reducing a risk of warping the terminal region PD of the display panel  100 . 
     In this embodiment, a surface  17   a  of the reinforcement layer  17 , a surface  18   a  of the first protective layer  18 , and a surface  19   a  of the second protective layer  19  define a space K. When the display panel  100  is in a bent state, a terminal of the first backplate  11  will be squeezed against the flexible substrate  13 , so that a portion of the terminal region PD close to the bending region BD is subjected to greater stress, and because the space K is close to the bending region BD, therefore the space K plays a role in releasing stress. 
     In some embodiments, the space K is filled with a flexible material to reduce a risk of breakage and separation of the suspended part of the second protective layer  19 . 
     In addition, separating the first protective layer  18  and the reinforcement layer  17  can prevent the first protective layer  18  from being attached to the reinforcement layer  17 , and thereby prevent affecting the attachment effect of the second protective layer  19  to the reinforcement layer  17 . 
     Optionally, a distance d from the first protective layer  18  to the reinforcement layer  17  is in a range from 0.2 mm to 0.5 mm. Optionally, the distanced may be 0.2 mm, 0.3 mm, 0.4 mm, and 0.5 mm. 
     In the display panel  100  of this embodiment, a boundary of the portion where the second protective layer  19  is connected to the reinforcement layer  17  is located in the terminal region PD. Specifically, the boundary of the portion where the second protective layer  19  is connected to the reinforcement layer  17  is located within an outer contour line of the first backplate  11 . This arrangement prevents the second protective layer  19  from extending to the bending area BD, and prevents affecting the bending effect of the display panel  100 . 
     In the display panel  100  of this embodiment, a thickness of the first protective layer  18  is equal to a thickness of the reinforcement layer  17 . This arrangement is convenient for attaching the second protective layer  19  to the reinforcement layer  17 . 
     In some embodiments, the thickness of the first protective layer  18  may also be less than or greater than the thickness of the reinforcement layer  17 . 
     In the display panel  100  of this embodiment, the thickness of the first protective layer  18  is less than the thickness of the second protective layer  19 . Since the first protective layer  18  fails to completely cover the metal trace  14 , a protective effect of a portion of the metal trace  14  not covered by the first protective layer  18  is relatively weak. Therefore, setting the second protective layer  19  thicker can improve a protective effect of the second protective layer  19  on the portion of the metal trace  14  corresponding to the space K. 
     In some embodiments, the thickness of the first protective layer  18  may also be greater than the thickness of the second protective layer  19 . Since the thickness of the second protective layer  19  is thinner and the flexibility of the second protective layer  19  is better, the second protective layer  19  can be easily attached to the curved surface of the reinforcement layer  17 , which can improve a tightness of the second protective layer  19  attached to the reinforcement layer  17 , and reduce a risk of the second protective layer  19  and the reinforcement layer  17  from being separated due to the bending of the display panel  100 . 
     In the display panel  100  in this embodiment, the thickness of the first protective layer  18  is in a range from 50 μm to 80 μm. For example, the thickness of the first protective layer  18  may be 50 μm, 60 μm, 70 μm, and 80 μm. The thickness of the second protective layer  19  is in a range from 50 μm to 100 μm. For example, the thickness of the second protection layer  19  may be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, and 100 μm. 
     In the display panel  100  of this embodiment, the elastic modulus of the first protective layer  18  is less than the elastic modulus of the second protective layer  19 . Since the first protective layer  18  fails to completely cover the metal trace  14 , the protection of the parts of the metal trace  14  that are not covered is relatively weak. Therefore, the second protective layer  19  with a greater elastic modulus can be selected to increase a rigidity of the second protective layer  19 , and further improves the protective effect of the second protective layer  19  on the portion of the metal trace  14  corresponding to the space K. 
     In the display panel  100  of this embodiment, the first protective layer  18  and the second protective layer  19  are made of the same material, and the first protective layer  18  and the second protective layer  19  are integrally formed. This arrangement is beneficial to improve the stability of the connection between the first protective layer  18  and the second protective layer  19 , as well as to improve the efficiency of the first protective layer  18  and the second protective layer  19  being attached to the insulating layer  15  and the reinforcement layer  17 , and to achieve an effect of simplifying the manufacturing process. 
     Optionally, the material of the first protective layer  18  and the second protective layer  19  may be materials such as polyethylene terephthalate (PET) or polyimide (PI). 
     In some embodiments, the first protective layer  18  and the second protective layer  19  may also be two independent film layers. The materials of the first protective layer  18  and the second protective layer  19  may also be different. 
     Optionally, the material of the reinforcement layer  17  is a curable material, such as ultraviolet curing glue, silica gel, or silicone glue. 
     In the display panel  100  of this embodiment, the circuit board  110  is disposed on the first portion  131 . The first protective layer  18  is provided with an opening  181 . The opening  181  penetrates the first protective layer  18  and the second protective layer  19 . A portion of the circuit board  110  is provided in the opening  181 . The opening  181  is provided to avoid the circuit board  110 , improve the assembly efficiency of the circuit board  110 , and save assembly space. 
     Optionally, a distance L from the hole wall of the opening  181  to the edge of the circuit board  110  is less than 1 mm. For example, the distance L can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, and 0.9 mm. 
     Optionally, the circuit board  110  may be a flexible circuit board or a printed circuit board. 
     In the terminal region of the display panel of the embodiment of the present disclosure, the first protective layer and the second protective layer are arranged on the flexible substrate, and the second protective layer is connected to the reinforcement layer, to reduce the risk of warpage in the terminal region and breakage of the metal trace of the flexible substrate. 
     The above is a detailed introduction to the display panel provided by embodiments of the present disclosure. Specific embodiments are used in this article to describe the principles and implementations of the present disclosure. The description of the above embodiments is only used to help understand the methods and the core idea of the present disclosure. At the same time, for those skilled in the art, according to the idea of the present disclosure, there will be changes in the specific implementation and the scope of application. In summary, the content of this specification should not be construed as a limitation to the present disclosure.