Patent Publication Number: US-2021183276-A1

Title: Display panel, display device, and method for manufacturing display panel

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of the PCT application No. PCT/CN2019/107315, filed on Sep. 23, 2019, which claims priority to Chinese Patent Application No. 201910015504.3, filed on Jan. 8, 2019, and the contents of both applications are herein incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of display, and particularly to a display panel. 
     BACKGROUND 
     With the development of information technology, display devices such as mobile phones have become indispensable tools in people&#39;s lives, and the “full screen display” has become the pursuit of more and more users. In order to make the flexible display panel achieve an effect of full screen display, a non-display area is usually bent to implement the effect of full screen display, that is, the non-display area of the flexible display panel is bent to the back of the flexible display panel to reduce the width of the border of the display panel, thereby improving the screen-to-body ratio. 
     SUMMARY 
     In view of this, it is necessary to provide a display panel which can effectively reduce a bending stress on metal traces in a bending area. 
     A display panel is provided, which includes a display area and a bending area located outside the display area; 
     and includes a substrate and a plurality of metal traces; 
     the substrate includes a first barrier layer provided with a plurality of through-hole grooves, and 
     the plurality of metal traces are located on the first barrier layer, and are arranged by avoiding the through-hole grooves on the first barrier layer. 
     In the above display panel, a plurality of through-hole grooves are provided on the first barrier layer. When the bending area of the display panel is bent, the through-hole grooves can release the bending stress on the first barrier layer, thereby reducing the stress of the first barrier layer acting on the metal traces, i.e., reducing the bending stress of the metal traces in the bending area, to effectively ensure the normal display of the display panel. 
     The present disclosure further provides a method for manufacturing a display panel. 
     A method for manufacturing a display panel includes: 
     forming a first barrier layer initial body of the substrate; 
     forming a metal layer on the first barrier layer initial body; and 
     sequentially or simultaneously patterning the metal layer and the first barrier layer initial body to form the metal traces and the first barrier layer having the through-hole grooves. 
     In the display panel manufactured by the method for manufacturing the display panel described above, a plurality of through-hole grooves are provided on the first barrier layer of the display panel. When the bending area of the display panel is bent, the through-hole grooves can release the bending stress on the first barrier layer, thereby reducing the stress of the first barrier layer acting on the metal traces, i.e., reducing the bending stress on the metal traces in the bending area, to effectively ensure the normal display of the display panel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structure diagram of a display panel provided by an embodiment of the present disclosure. 
         FIG. 2  is a schematic cross-sectional view of a bending area of the display panel in  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view of the bending area of the display panel in  FIG. 2  when no planarization layer is formed. 
         FIG. 4  is a schematic cross-sectional view of a bending area of a display panel provided by another embodiment of the present disclosure. 
         FIG. 5  is a schematic cross-sectional view of a bending area of a display panel provided by another embodiment of the present disclosure. 
         FIG. 6  is a top view of the bending area of the display panel in  FIG. 5 . 
         FIG. 7  is a schematic cross-sectional view of a display panel provided by another embodiment of the present disclosure when no planarization layer is formed. 
         FIG. 8  is a flow chart showing a method for manufacturing a display panel according to an embodiment of the present disclosure. 
         FIG. 9  is a flow chart showing a method for manufacturing a display panel according to another embodiment of the present disclosure. 
         FIG. 10  is a flow chart showing a method for manufacturing a display panel according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The display panel includes a display area and a bending area located outside the display area. The bending area of the display panel includes a substrate and metal traces formed on the substrate. During the bending process, stress concentration is easily produced on metal traces in the bending area of the display panel. When the stress concentration is serious, normal display of the display panel is affected. When the bending area of the display panel is bent, stress concentration is easily produced on the metal trace in the bending area. When the stress concentration is serious, it can affect the normal display of the display panel. 
     A reason for which the stress concentration is easily produced on the metal trace in the bending area when the bending area of the display panel is bent lies in that: the substrate of the bending area includes a flexible substrate and a barrier layer formed on one side of the flexible substrate adjacent to the metal trace. The barrier layer is generally formed by an inorganic material with a greater hardness. Therefore, when the bending area is bent, a larger bending stress is easily produced in the barrier layer, and then directly or indirectly acts on the metal trace, thereby causing the stress concentration to be produced on the metal trace. When the stress concentration is serious, it may cause the metal trace in the bending area to break, thereby further affecting the normal display of the display panel. 
     In view of this, the present disclosure provides a display panel in which the bending stress on the metal trace in the bending area can be reduced, a display device including the display panel and a method for manufacturing the display panel. 
     It should be noted that when it is considered that another element is “formed” on one element, the another element is directly formed or there is also an intermediate element. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure applies. The terms used in the specification of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. 
     As shown in  FIG. 1  to  FIG. 3 , a display panel  100  provided by an embodiment of the present disclosure includes a display area  110  and a bending area  130  located outside the display area  110 . 
     The bending area  130  includes a substrate  131  and a plurality of metal traces  133 . 
     The substrate  131  includes a first barrier layer  1317 . The first barrier layer  1317  is provided with a plurality of through-hole grooves  1316 . The metal traces  133  are located on the first barrier layer  1317 . The metal traces  133  are arranged by avoiding the through-hole grooves  1316  on the first barrier layer  1317 . That is, projections of the metal traces  133  on the first barrier layer  1317  deviate from the through-hole grooves  1316 , for example, the projections of the metal traces  133  do not overlap the through-hole grooves  1316 . 
     The substrate  131  may further include a first flexible substrate  1313 , a second flexible substrate  1311 , and a second barrier layer  1315 . The first barrier layer  1317 , the first flexible substrate  1313 , the second barrier layer  1315 , and the second flexible substrate  1311  are sequentially stacked. The first barrier layer  1317  is configured to prevent the metal traces  133  from being eroded by water and oxygen. The metal traces  133  are located on one side of the first barrier layer  1317  away from the first flexible substrate  1313 . 
     When the bending area  130  of the display panel  100  is bent, the through-hole grooves  1316  can release a bending stress on the first barrier layer  1317 , thereby reducing a stress acting by the first barrier layer  1317  on the metal traces  133 , which can effectively prevent the breakage of the metal traces  133  in the bending area  130 , so as to effectively ensure the normal display of the display panel  100 . The metal traces  133  can be directly provided on a surface of the first barrier layer  1317 , or another material layer can be provided between the metal traces  133  and the first barrier layer  1317 . 
     In the embodiment, the substrate  131  can include two barrier layers, a second barrier layer  1315  and a first barrier layer  1317 . Since no through-hole groove  1316  is provided on the second barrier layer  1315 , which can act to block water and oxygen. Therefore, the through-hole grooves  1316  can be provided on the first barrier layer  1317 . 
     In the embodiment, the bending area  130  surrounds all side edges of the display area  110 . Of course, according to requirements, in other embodiments, the bending area  130  can also be only outside part of the side edges of the display area  110 . 
     The bending area  130  of the display panel  100  can further include at least one of an active layer, a planarization layer  135 , an anode layer, a pixel definition layer, a support pillar layer. 
     In the embodiment, at least one through-hole groove  1316  is correspondingly provided between every two adjacent metal traces  133 . Accordingly, the through-hole groove  1316  release a bending stress of the first barrier layer  1317  under a metal trace  133  from both sides of the metal trace  133 , so as to avoid that the bending stress is transmitted to the metal trace  133  over the first barrier layer  1317  due to an excessive local bending stress of the first barrier layer  1317 , i.e., a situation where the metal trace  133  is broken caused by the stress concentration on partial metal trace  133  is avoided, thereby effectively ensuring the display effect of the display panel  100 . 
     In the embodiment, the through-hole groove  1316  can extend along an extension direction of an adjacent metal trace  133 . Accordingly, the bending stress of the first barrier layer  1317  under the metal trace  133  can be released more evenly, thereby avoiding the excessive local stress on the first barrier layer under the metal trace  133 . 
     In the embodiment, an area of the first barrier layer  1317  where no through-hole groove  1316  is provided is located under the metal trace  133 . In other words, portions of the first barrier layer  1317  which are not covered by the metal traces  133  are all dug to form through-hole grooves  1316 , so that the first barrier layer  1317  is in a discontinuous state, thereby increasing the bending resistance of the first barrier layer  1317  to a greater extent. 
     Specifically, in the embodiment, the second barrier layer  1315  and the first barrier layer  1317  may both be a silicon nitride layer or a silicon oxide layer. Apparently, the second barrier layer  1315  and the first barrier layer  1317  may also be other inorganic film layers commonly used in the art. 
     As shown in  FIG. 4 , a display panel  100  is provided by another embodiment of the present disclosure, which differs from the display panel  100  in that, a groove  2318  is provided in an area of the first barrier layer  2317  where no through-hole groove  2316  is provided. A depth of the groove  2318  is less than a thickness of the first barrier layer  2317 . Accordingly, the bending resistance of the first barrier layer  2317  in the area is increased to better reduce the bending stress acting on the metal trace  133 . 
     Specifically, in the embodiment, the groove  2318  can be provided on one side of the first barrier layer  2317  adjacent to the metal trace  133 . Apparently, in other embodiments, the groove can also be provided on one side of the first barrier layer away from the metal trace  133 , or the grooves can be provided on one side of the first barrier layer away from the metal trace  133  and on one side of the first barrier layer adjacent to the metal trace  133 , as long as it is guaranteed that the grooves do not make the flexible substrate under the first barrier layer exposed. 
     Further, in another embodiment, a buffer material can further be provided in the groove  2318  to relieve the bending stress of the first barrier layer  2317 , thereby further reducing the bending stress acting on the metal trace  133 . It should be appreciated that, when the groove  2318  is provided on one side of the first barrier layer  2317  adjacent to the metal trace  133 , the buffer material provided in the groove  2318  cannot contain water vapor or generate water vapor under a condition such as a high temperature, to prevent the metal trace  133  from being oxidized. 
     As shown in  FIGS. 5 and 6 , a display panel  100  is provided by another embodiment of the present disclosure, which differs from the display panel  100  in that, a plurality of through holes  337  passing through the metal trace  333  and the first barrier layer  3317  are provided in the bending area. The through hole  337  can simultaneously increase the bending resistances of the first barrier layer  3317  and the metal trace  333 . That is, when the display panel  300  is bent, the through hole  337  can release and reduce the bending stress of the first barrier layer  3317  and the metal trace  333 . The bending stress of the first barrier layer  3317  is reduced, and the stress of the first barrier layer  3317  acting on the metal trace  333  is correspondingly reduced, thereby better reducing the bending stress acting on the metal trace  333 . 
     In another embodiment, the substrate can further include more than two barrier layers and more than two flexible substrates. 
     Specifically, as shown in  FIG. 7 , a display panel  100  is provided by another embodiment of the present disclosure, which differs from the display panel  100  in that, the substrate  431  further includes a third barrier layer  4312  located on one side of the second barrier layer  4315  away from the first barrier layer  4317 . The through-hole groove  4316  passes through the second barrier layer  4315 . By this time, the third barrier layer  4312  is configured to prevent the metal trace and the like from being eroded. 
     Apparently, the substrate  431  may further include a third flexible substrate  4314 . The first barrier layer  4317 , the first flexible substrate  4313 , the second barrier layer  4315 , the second flexible substrate  4311 , the third barrier layer  4312 , and the third flexible substrate  4314  are sequentially stacked. 
     An embodiment of the present disclosure further provides a display device including the display panel  100 . 
     The above-mentioned display device includes the display panel  100 , a plurality of through-hole grooves  1316  are provided on the first barrier layer  1317  of the display panel  100 . When the bending area  130  of the display panel  100  is bent, the through-hole grooves  1316  can release the bending stress on the first barrier layer  1317 , thereby reducing the stress of the first barrier layer  1317  acting on the metal trace  133 , which can effectively prevent the breakage of the metal trace  133  in the bending area  130 , to ensure the normal display of the display panel  100  and increase the service life of the display device. 
     As shown in  FIG. 8 , an embodiment of the present disclosure further provides a method for manufacturing the display panel  100 , which includes the following steps. 
     At step S 01 , a first barrier layer initial body of the substrate  131  is formed. 
     It can be understood that the first barrier layer initial body is a first barrier layer  1317  without a through-hole groove  1316 . 
     In addition, before the first barrier layer initial body is formed, a second flexible substrate  1311 , a second barrier layer  1315 , and a first flexible substrate  1313  are sequentially formed in a stacking form. 
     At step S 02 , a metal layer is formed on the first barrier layer initial body. 
     At S 03 , the metal layer and the first barrier layer initial body are sequentially patterned to form a plurality of metal traces  133  and a first barrier layer  1317 . 
     In other words, both the metal traces  133  and the first barrier layer  1317  are finally formed by patterning. In addition, the process of patterning the first barrier layer initial body is the process of forming the through-hole groove  1316  on the first barrier layer  1317 . 
     It should be understood that, as shown in  FIG. 9 . the method for manufacturing the display panel  100 , after the step S 01 , further includes the following steps. 
     At step A 01 , an active layer is formed on the first barrier layer initial body. 
     At step A 02 , a gate trace layer is formed on the active layer. 
     At step A 03 , a capacitance plate layer is formed on the gate trace layer. 
     At step A 04 , a source-drain trace layer is formed on the capacitance plate layer. 
     Apparently, the method further includes a step of forming an inorganic film layer and forming a via hole between two of the active layer, the gate trace layer, the capacitance plate layer, and the source-drain trace layer. The step S 02  may include at least one of the step A 02 , the step A 03 , and the step A 04 . 
     In addition, after the step S 03 , the method further includes a step of forming a planarization layer, an anode layer, a pixel definition layer, a support pillar layer, and the like. It should be understood that, the step of forming the planarization layer, the anode layer, the pixel definition layer, and the support pillar layer is performed after the step A 04 . 
     In the display panel  100  manufactured by the method for manufacturing the display panel described above, a plurality of through-hole grooves  1316  are provided on the first barrier layer  1317  of the display panel  100 . When the bending area  130  of the display panel  100  is bent, the through-hole grooves  1316  can release the bending stress on the first barrier layer  1317 , thereby reducing the stress of the first barrier layer  1317  on the metal traces  133 , which can effectively prevent the breakage of the metal traces  133  in the bending area  130 , to ensure the normal display of the display panel  100 . 
     In addition, the inventors discovered through research that if the first barrier layer having through-hole grooves is directly formed, the flexible substrate is exposed. When the metal layer is formed, the exposed flexible substrate may cause chamber contamination. 
     In the above method for manufacturing the display panel  100 , the first barrier layer initial body is not patterned before the metal layer is formed, so that the phenomenon that the second flexible substrate  1311  is exposed when the metal layer is formed is avoided, thereby effectively preventing the chamber contamination caused by the exposed first flexible substrate  1313  when the metal layer is formed. 
     In the embodiment, the metal layer and the first barrier layer initial body are sequentially patterned, which means that the metal layer and the first barrier layer initial body are sequentially patterned through two processes. Specifically, the mode of patterning the metal layer is as follows: a photomask is employed to expose the metal layer; the metal layer is etched by an etching method to form the metal traces  133 . The mode of patterning the first barrier layer initial body is as follows: a photomask is employed to expose the first barrier layer initial body; the first barrier layer initial body is etched by an etching method to form the first barrier layer  1317 . 
     In another embodiment, the metal layer and the first barrier layer initial body can be simultaneously patterned. Specifically, as shown in  FIG. 10 , the steps of simultaneously patterning the metal layer and the first barrier layer initial body to form the plurality of metal traces  133  and the first barrier layer  1317  includes following steps. 
     At step S 031 , the metal layer is exposed by using a photomask. 
     At step S 032 , the metal layer and the first barrier layer initial body are etched simultaneously by an over etching mode to form the plurality of metal traces  133  and the first barrier layer  1317 . 
     It should be understood that, the simultaneous patterning of the metal layer and the first barrier layer initial body can effectively improve production efficiency. 
     The technical features of the above-described embodiments can be combined arbitrarily. To simplify the description, all possible combinations of the technical features in the above embodiments are not described. However, all of the combinations of these technical features should be considered as within the scope of the present disclosure, as long as these combinations do not contradict with each other. 
     The above-described embodiments merely represent several exemplary embodiments of the present disclosure, and the description thereof is more specific and detailed, but these embodiments should not be construed as limiting the scope of the present disclosure. It should be noted that, several modifications and improvements can be made by those of ordinary skill in the art without departing from the concept of the present disclosure, and these modifications and improvements are all within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the appended claims.