Patent Publication Number: US-2023165038-A1

Title: Display panel and mobile terminal

Description:
FIELD OF INVENTION 
     The present application relates to a display technology field, especially to a fabrication of display device, and particularly to a display panel and a fabrication method thereof, and a mobile terminal. 
     BACKGROUND 
     With the increasing demand for high-screen-to-body ratio products, a camera under panel (CUP) technology is thus emerged. 
     Among them, a camera area under a panel of a CUP product needs to use a transparent conductive material that is different from a metal material in other areas to ensure the shooting effect of the camera and the normal display effect of the camera area. At the same time, it is necessary to add an organic film layer for separating the organic film layer with other film layers. With the increase in the number of organic film layers, due to the strong fluidity of the organic film layer materials and the less width of the multi-layer organic film layer forming a dam structure, the organic film layer materials will overflow all around, resulting in a thickness of a final actual formation of the dam structure is much lower than a design value, which reduces a reliability of the dam structure. 
     Therefore, existing CUP products have the problem of a too low thickness of the dam structure, which is in urgent need of improvement. 
     SUMMARY OF DISCLOSURE 
     The embodiments of the present application provide a display panel and a mobile terminal to solve the existing thickness loss caused by the overflow of the upper organic film layer in a dam structure to the lower organic film layer, which results in technical problems with low reliability of the dam structure. 
     An embodiment of the preset application provides a display panel, wherein the display panel comprises a display area and a non-display area surrounding the display area, and the display panel comprises: 
     an array substrate; 
     a dam structure, wherein the dam structure is on the array substrate and in the non-display area, the dam structure comprises a plurality of dam layers which are stacked layer by layer, and the plurality of dam layers comprise a first dam layer on the array substrate and a second dam layer on the first dam layer, and a width of the second dam layer is less than or equal to a width of the first dam layer in a cross-section of the display panel; 
     an organic layer group on the array substrate and in the display area, and an absolute value of the difference between a thickness of the organic layer group and a thickness of the dam structure is less than or equal to a first predetermined threshold value; and 
     a light-emitting layer on a side of the organic layer group away from the array substrate and in the display area; 
     wherein the array substrate comprises an inorganic layer group and a thin film transistor layer located at least in the inorganic layer group, and the organic layer group comprises: 
     a planarization layer on a side of the inorganic layer group close to the light-emitting layer; 
     a pixel definition layer on a side of the planarization layer close to the light-emitting layer; 
     a supporting layer on a side of the pixel definition layer close to the light-emitting layer; 
     wherein a difference between a gap from the side of the array substrate away from the supporting layer to the side of the supporting layer away from the array substrate and a gap from the side of the array substrate away from the dam structure to the side of the dam structure away from the array substrate is less than or equal to the first predetermined threshold value; and 
     wherein the first predetermined threshold value is less than or equal to 2 micrometers. 
     In one embodiment, in a top view of the display panel, an edge of the second dam layer overlaps an edge of the first dam layer, or the edge of the second dam layer is within the first dam layer. 
     In one embodiment, in every two adjacent dam layers, a width of the dam layer farther from the array substrate is less than a width of the dam layer closer to the array substrate. 
     In one embodiment, at least one of the dam layers is provided in a layer of at least one of the planarization layer, the pixel definition layer, and the supporting layer, and a material of each of the dam layers is the same as a material of the planarization layer, the pixel definition layer or the supporting layer arranged in the same layer. 
     In one embodiment, a groove is provided in the first dam layer, and the second dam layer is in the groove. 
     In one embodiment, the dam structure further comprises: 
     at least one first overflow layer, wherein in at least one set of two adjacent dam layers, the overflow layer at least extends from the side of the dam layer away from the array substrate to the side of the dam wall layer close to the array substrate. 
     Another embodiment further provides a display panel, wherein the display panel comprises a display area and a non-display area surrounding the display area, and the display panel comprises: 
     an array substrate; 
     a dam structure, wherein the dam structure is on the array substrate and in the non-display area, the dam structure comprises a plurality of dam layers which are stacked layer by layer, and the plurality of dam layers comprise a first dam layer on the array substrate and a second dam layer on the first dam layer, and a width of the second dam layer is less than or equal to a width of the first dam layer in a cross-section of the display panel; 
     an organic layer group on the array substrate and in the display area, and an absolute value of the difference between a thickness of the organic layer group and a thickness of the dam structure is less than or equal to a first predetermined threshold value; and 
     a light-emitting layer on a side of the organic layer group away from the array substrate and in the display area. 
     In one embodiment, the first predetermined threshold value is less than or equal to 2 micrometers. 
     In one embodiment, in a top view of the display panel, an edge of the second dam layer overlaps an edge of the first dam layer, or the edge of the second dam layer is within the first dam layer. 
     In one embodiment, in the cross-section of the display panel, a distance between a side of the second dam layer and a side of the first dam layer is less than or equal to a second predetermined threshold value. 
     In one embodiment, in every two adjacent dam layers, a width of the dam layer far from the array substrate is less than a width of the dam layer closer to the array substrate. 
     In one embodiment, the array substrate comprises an inorganic layer group and a thin film transistor layer located at least in the inorganic layer group, and the organic layer group comprises: 
     a planarization layer on a side of the inorganic layer group close to the light-emitting layer; 
     a pixel definition layer on a side of the planarization layer close to the light-emitting layer; 
     a supporting layer on a side of the pixel definition layer close to the light-emitting layer; 
     wherein a difference between a gap from the side of the array substrate away from the supporting layer to the side of the supporting layer away from the array substrate and a gap from the side of the array substrate away from the dam structure to the side of the dam structure away from the array substrate is less than or equal to the first predetermined threshold value. 
     In one embodiment, at least one of the dam layers is provided in a layer of at least one of the planarization layer, the pixel definition layer, and the supporting layer, and a material of each of the dam layers is the same as a material of the planarization layer, the pixel definition layer or the supporting layer arranged in the same layer. 
     In one embodiment, the planarization layer comprises: 
     a first planarization layer on the side of the inorganic layer group close to the light-emitting layer, and a conductive layer is provided on the first planarization layer; and 
     a second planarization layer on the side of the first planarization layer and the conductive layer close to the light-emitting layer. 
     In one embodiment, in a cross-section of the display panel, a width of a side of the dam structure away from the array substrate is greater than or equal to 6 micrometers. 
     In one embodiment, a groove is provided in the first dam layer, and the second dam layer is in the groove. 
     In one embodiment, the plurality of the dam layers on the second dan layer are also in the groove. 
     In one embodiment, among the plurality of dam layers located on the first dam layer, at least one of the dam layers is provided with a groove, and at least one dam layer is arranged in the groove. 
     In one embodiment, the dam structure further comprises: 
     at least one first overflow layer, wherein in at least one set of two adjacent dam layers, the overflow layer at least extends from the side of the dam layer away from the array substrate to the side of the dam wall layer close to the array substrate. 
     An embodiment of the present application provides a mobile terminal, wherein the mobile terminal comprises a terminal body and any of the previous display panels, and the terminal body and the display panel are combined into one assembly. 
     In the present application, a display panel and a mobile terminal are provided, and the display panel comprises a display area and a non-display area surrounding the display area, and the display panel comprises: an array substrate; a dam structure, wherein the dam structure is on the array substrate and in the non-display area, the dam structure comprises a plurality of dam layers which are stacked layer by layer, and the plurality of dam layers comprise a first dam layer on the array substrate and a second dam layer on the first dam layer, and a width of the second dam layer is less than or equal to a width of the first dam layer in a cross-section of the display panel; an organic layer group on the array substrate and in the display area, and an absolute value of the difference between a thickness of the organic layer group and a thickness of the dam structure is less than or equal to a first predetermined threshold value; and a light-emitting layer on a side of the organic layer group away from the array substrate and in the display area. In the present application, the width of the second dam layer is set to be less than or equal to the width of the first dam layer, and the absolute value of the difference between the thickness of the organic layer group and the thickness of the dam structure is less than or equal to the first predetermined threshold value as a limitation, that is, the risk of overflow of the film used to form the second dam layer to the film used to form the first dam layer during the fabrication process can be reduced, thereby reducing a risk of the less thickness of the second dam layer, and improves the reliability of the dam structure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In order to more clearly illustrate technical solutions in embodiments of the present disclosure, a brief description of accompanying drawings used in a description of the embodiments will be given below. Obviously, the accompanying drawings in the following description are merely some embodiments of the present disclosure. For those skilled in the art, other drawings may be obtained from these accompanying drawings without creative labor. 
         FIG.  1    is a schematic cross-sectional view of a first display panel provided by an embodiment of the application. 
         FIG.  2    is a schematic cross-sectional view of a second display panel provided by an embodiment of the application. 
         FIG.  3    is a schematic cross-sectional view of a third display panel provided by an embodiment of the application. 
         FIG.  4    is a schematic cross-sectional view of a fourth display panel provided by an embodiment of the application. 
         FIG.  5    is a schematic cross-sectional view of a fifth display panel provided by an embodiment of the application. 
         FIG.  6    is a schematic cross-sectional view of a sixth display panel provided by an embodiment of the application. 
         FIG.  7    is a flowchart of a fabrication method of a display panel provided by an embodiment of the application. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments of the present application provide a display panel and a fabrication method thereof, and a mobile terminal. Detailed descriptions are given below. It should be noted that the order of description in the following embodiments is not intended to limit the preferred order of the embodiments. 
     In the description of this application, it should be understood that the directions or positional relationships indicated by the terms “upper”, “lower”, “far away”, “near”, etc. are based on the directions or positional relationships shown in the drawings, for example, ““Upper” only means that the surface is above the object, and specifically refers to directly above, obliquely above, or the upper surface, as long as it is above the level of the object. The upper position or positional relationship is only for the convenience of describing the application and simplifying the description, and is not an indication It may also imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. 
     In addition, it should be noted that the drawings provide only the structures and steps that are relatively closely related to the application, and omit some details that are not relevant to the application. The purpose is to simplify the drawings so that the application points are clear at a glance, rather than showing the actual device and method are exactly the same as the drawings, and they are not a limitation of the actual device and method. 
     The present application provides a display panel, which includes but is not limited to following embodiments and combinations between the following embodiments. 
     In one embodiment, as shown in  FIG.  1 - 6   , a display panel  100  comprises a display area  01  and a non-display area  02  surrounding the display area  01 . The display panel  100  comprises an array substrate  10  and a dam structure  20 . The dam structure  20  is on the array substrate  10  and in the non-display area  02 , and the dam structure  20  comprises a plurality of dam layers stacked layer by layer. The plurality of the dam layers comprises a first dam layer  201  on the array substrate  10  and a second dam layer  202  on the first dam layer  201 . In a cross-section of the display panel  100 , a width of the second dam layer  202  is less than or equal to a width of the first wall layer  201 . An organic layer group  30  is on the array substrate  10  and in the display area  01 , and an absolute value of a difference between the thickness of the organic layer group  30  and a thickness of the dam structure  20  is less than or equal to a first predetermined threshold value. A light-emitting layer  40  is on a side of the organic layer group  30  away from the array substrate  10  and in the display area  01 . 
     Herein, the non-display area  02  may be arranged around at least one side of the display area  01 , and the dam structure  20  in the non-display area  02  may be arranged along a path that the non-display area  02  surrounds the display area  01 . That is, the organic layer group in the display area  01  is surrounded by the dam structure  20 . Specifically, as shown in  FIG.  6   , the array substrate  10  comprises an inorganic layer group  101  and a thin film transistor layer  102  at least located in the inorganic layer group  101 . The thin film transistor layer  102  comprises an active layer  1021 , a gate layer  1022  on the active layer  1021 , and a source  1023  and a drain  1024  on the gate layer  1022 . The source  1023  can be electrically connected to a side of the active layer  1021  through a via hole in the inorganic layer group  101 , and the drain  1024  can be electrically connected to another side of the active layer  1021  through a via hole in the inorganic layer group  101 . The inorganic layer group  101  comprises a first inorganic layer  1011  between the gate layer  1021  and the gate layer  1022 , and a second inorganic layer  1012  between the gate layer  1022 , the source electrode  1023 , and the drain electrode  1024 . An anode layer in the light-emitting layer  40  is able to electrically connected the drain  1024  through a via hole in the organic layer group  30 . Moreover, the array substrate  10  may further comprise a substrate  103  for carrying the inorganic layer group  101 , and the substrate  103  may be a flexible substrate or a rigid substrate. 
     Specifically, a side of the dam structure  20  close to the array substrate  10  and a side of the organic layer group  30  close to the array substrate  10  may be located on the same horizontal plane. It is noted that the width of the second dam layer  202  is set to be less than or equal to the width of the first dam layer  201  to ensure that a constituent material of the second dam layer  202  will not overflow along a direction toward the first dam layer  201  to lose the thickness of the second dam layer  202 . 
     In one embodiment, as shown in  FIGS.  1 - 6   , in a top view of the display panel  100 , an edge of the second wall layer  202  overlaps an edge of the first wall layer  201 , or an edge of the second dam layer  202  is located within the dam layer  201 . It can be understood that, in this embodiment, the side of the second dam layer  202  is set to not exceed the side of the first dam layer  201 , that is, a size of the second dam layer  202  is less than a size of the first dam layer  201  in any direction parallel to the array substrate  10 , which can further ensure that the constituent material of the second dam layer  202  will not overflow along a direction toward the first dam layer  201  to lose the thickness of the second dam layer  202 . 
     In one embodiment, the predetermined first threshold value in the present application may be less than or equal to 2 micrometers. That is, in this embodiment, it can be achieved through the foregoing embodiment and also defines the absolute value of the difference between the thickness of the organic layer group  30  and the thickness of the dam structure  20  may be less than or equal to 2 micrometers, so that the difference between thereof is small enough or even close to the same. It is understood that, on the one hand, the dam structure  20  can block external moisture from directly entering the display area  01 , and prevent organic packaging materials in the display area  01  from overflowing into the non-display area  02 , thereby improving a reliability of packaging of the display panel  100 . In addition, the dam structure  20  can also support a photomask for a vapor deposition process to prevent the photomask from contacting the plurality of organic layer groups  30  in the display area  01 , which may scratch the plurality of the organic layer groups  30 . 
     In one embodiment, as shown in  FIGS.  1 - 6   , in a cross-section of the display panel  100 , a gap between a side of the second dam layer  202  and a side of the first dam layer  201  is less than or equal to a second predetermined threshold value. It should be noted that, combined with the above description, when the gap between the side of the second dam layer  202  and the side of the first dam layer  201  is too large, the widths of the second dam layer  202  and the dam layer on the second dam layer  202  are too small to support the photomask. Therefore, on the basis of that the width of the second dam layer  202  is less than or equal to the first dam layer  201  in this embodiment, the difference between widths thereof can be further restricted to be reduced, thereby ensuring the width of the second dam layer  202  and the width of the dam layer on the second dam layer  202  are sufficient to support the photomask. 
     Specifically, each of the organic layer groups  30  and the corresponding dam layer are arranged in the same layer, that is, each of the organic layer groups  30  and the corresponding dam layer can be fabricated at the same time through the same fabrication process. It is noted that, since a size of a projection of the multiple thin layers in the display area  01  on the array substrate  10  is much larger than a size of a projection of the dam structure on the array substrate  10 , and a thickness loss caused by a material overflow of the dam structure during the fabrication process is thus more obvious. 
     Specifically, in a direction from the array substrate  10  to the dam structure  20 , the first dam layer  201  and the second dam layer  202  may be two adjacent dam layers among a plurality of the dam layers. In particular, the side of the second wall layer  202  in this embodiment does not exceed the side of the first wall layer  201 . That is, a projection of the side of the second dam layer  202  on the array substrate  10  is within a projection of the first dam layer  201  on the array substrate  10 , and it also satisfies that an overall size of the multiple dam layers is greater than or equal to an overall size of the multiple film layers on this basis. 
     In one embodiment, as shown in  FIGS.  1 - 6   , in every two adjacent dam layers, a width of the dam layer farther away from the array substrate  10  is less than a width of the dam layer closer to the array substrate  10 . In combination with the above description, it can be seen that in any direction parallel to the array substrate  10 , the size of the second dam layer  202  is less than the size of the first dam layer  201 , and an overall size of the plurality of the dam layers is greater than or equal to an overall size of the multiple film layers, which can reduce the risk that a relative less thickness of the second dam layer  202 . Further, in this embodiment, in the direction from the array substrate  10  to the dam structure  20 , the sizes of the plurality of dam layers in any direction parallel to the array substrate  10  are sequentially reduced. That is, in every two adjacent dam layers, a projection of the dam layer away from the array substrate  10  on the array substrate  10  is in a projection of the dam layer close to the array substrate  10  on the array substrate  10 . It is understood that sizes of the plurality of dam layers is further limited in this embodiment, and for the same reason, the risk of a relive less thickness of the second dam layer  202  and the plurality of the dam layers on the second dam layer is further reduced, thereby improving the reliability of the dam structure  20  in applications. 
     In one embodiment, as shown in  FIGS.  1 - 6   , the organic layer group  30  comprises a planarization layer  301  on a side of the inorganic layer group  101  close to the light-emitting layer  40 , a pixel definition layer on a side of the planarization layer  301  close to the light-emitting layer  40 , and a supporting layer on a side of the pixel definition layer  302  close to the light-emitting layer  40 . Herein, a difference between a gap between a side of the array substate away from the supporting layer to a side of the supporting layer away from the array substrate and a gap between a side of the array substate  10  away from a side of the dam structure  20  and a side of the dam structure  20  away from the array substrate  10  is less than or equal to the first predetermined threshold value. 
     Specifically, as shown in  FIG.  1    to  FIG.  6   , the planarization layer  301  may be on a side of the source  1023 , the drain  1024 , and the inorganic layer group  101  close to the light-emitting layer, and the pixel defining layer comprises a plurality of pixel defining portions  3051 . A light-emitting layer  40  is provided between two adjacent pixel defining portions, and an anode layer in the light-emitting layer  40  may be connected to the drain  1024  a via hole in the planarization layer  301 . The supporting layer may comprise a plurality of supporting portions corresponding to the plurality of pixel defining portions  3051  one by one, and each of the supporting portions is one side of the corresponding pixel defining portion  3051  away from the array substrate  10 . 
     It is understandable that, compared with the above described “an absolute value of a difference between the thickness of the organic layer group  30  and a thickness of the dam structure  20  is less than or equal to a first predetermined threshold value”, a specific structure of the organic layer group  30  in this embodiment has been refined, and a thickness of the array substrate  10  has also been considered. A difference between a gap between a side of the array substate away from the supporting layer to a side of the supporting layer away from the array substrate and a gap between a side of the array substate  10  away from a side of the dam structure  20  and a side of the dam structure  20  away from the array substrate  10  is less than or equal to the first predetermined threshold value, so an upper surface of the supporting layer and an upper surface of the dam structure  20  are on the same plane, thereby improving the reliability of the dam structure  20  in applications. 
     In an embodiment, as shown in  FIG.  6   , at least one dam layer is provided in at least one of the planarization layers  301 , the pixel definition layer, and the support layer, and a constituent material of each dam layer is the same as a constituent material of the planarization layer  301 , the pixel definition layer or the support layer provided in the same layer. Specifically, the first dam layer  201  and the second dam layer  202  as a whole can be arranged in the same layer as the planarization layer  301 , and constituent materials of these three layers can be the same. A plurality of the pixel defining layers defined by the pixel defining portion  3051  can be arranged in the same layer as the dam layer  205  on the second dam layer  202 , and constituent materials of the two layers can be the same. The supporting layer can also be arranged in the same layer as the dam layer on the fifth dam layer  205 , and constituent materials of these two layers can be the same. 
     In one embodiment, as shown in  FIG.  6   , the planarization layer  301  comprises a first planarization layer  3011  on a side of the inorganic layer group  101  close to the light-emitting layer  40 , having a conductive layer  50  on the first planarization layer  3011 , and a second planarization layer  3012  on a side of the first planarization layer  3011  and the conductive layer  50  close to the light-emitting layer. Specifically, the conductive layer  50  may be electrically connected to the drain  1024  through a via hole in the first planarization layer  3011 , and the anode layer in the light-emitting layer  40  may be electrically connected to the drain  1024  through a via hole in the second planarization layer  3012 . A constituent material of the conductive layer  50  is different from and a material of the drain  1024 , that is, the second planarization layer  3012  can be used to divide the conductive layer  50  and the layer where the drain  1024  is located. 
     Specifically, the first dam layer  201  can be provided in the same layer as the first planarization layer  3011  and is made of the same material, and the second dam layer  202  can be provided in the same layer as the second planarization layer  3012  and is made of the same material. Furthermore, as shown in  FIGS.  1 - 6   , the organic layer group  30  may further comprise a third organic layer  303  and a fourth organic layer  304  between the planarization layer  301  and the pixel defining layer formed by the plurality of pixel defining portions  3051 . Furthermore, the dam structure  20  may also comprise a third dam layer  203  and a fourth dam layer  204  stacked between the second dam layer  202  and the fifth dam layer  205 . Herein, the third organic layer  303  and the third dam layer  203  can be arranged in the same layer and made of the same material, the fourth organic layer  304  and the fourth dam layer  204  can be arranged on the same layer and made of the same material. Furthermore, the multiple film layers in the organic layer group  30  may correspond to the multiple dam layers in the dam structure  20  one by one, and each film layer in the organic layer group  30  is arranged on the same layer as the corresponding dam layer. 
     In one embodiment, as shown in  FIGS.  2 - 3   , the first dam layer  201  is provided with a groove, and the second dam layer  202  is located in the groove. Specifically, the first dam layer  201  may be provided with a first groove  401 , and the second dam layer  202  is located in the first groove  401 . That is, the first groove  401  can at least receive the second dam layer  202 . Furthermore, in the direction from the array substrate  10  to the dam structure  20 , the size of the first groove  401  may be greater than or equal to the size of the second dam layer  202 . 
     It is understandable that on the basis that a side of the second dam layer  202  is not beyond a side of the first dam layer  201 , the second dam layer  202  in this embodiment is disposed inside the first groove  401 . That is, the side of the first dam layer  201  may surround the second dam layer  202 . It is known by combining “in the direction from the array substrate  10  to the dam structure  20 , the size of the first groove  401  may be greater than or equal to the size of the second dam layer  202 ” and “in the direction from the array substrate  10  to the dam structure  20 , the overall size of the plurality of the dam layers is greater than or equal to the overall size of the multiple film layers”, the risk of the film layer forming the second dam layer  202  flows outside the first groove  401  is reduced during formation of the second dam layer  202 , thereby reducing the risk of reducing the film used to form the second dam layer  202 , and reducing the risk that a less thickness of the second dam layer  202 , improving the reliability of the dam structure  20  in applications. Herein, the shape of the first groove  401  is not limited here, and it is necessary to prevent the film used to form the second dam layer  202  from overflowing outside the first groove  401  during the fabrication process. 
     It should be noted that, as shown in  FIG.  2   , when at least one dam layer is further provided on the second dam layer  202 , the size of the first groove  401  may be equal to the size of the second dam layer  202  in the direction from the array substrate  10  to the dam structure  20 . Similarly, furthermore, in every two adjacent dam layers on the second dam layer  202 , the side of the dam layer far away from the array substrate  10  may not exceed the side of the dam layer close to the array substrate  10 . When the second dam layer  202  is provided with a layer made of a material of poor fluidity, the first groove  401  can also accommodate the layer made of the material with poor fluidity. Furthermore, it is understood that by combining “in the direction from the array substrate  10  to the dam structure  20 , the overall size of the multiple dam layers is greater than or equal to the overall size of the multiple film layers”, in the direction from the array substrate  10  to the dam structure  20  in this embodiment, the distance between the side of the first dam layer  201  close to the array substrate  10  and the bottom of the first groove  401  may be greater than or equal to the size of the film layer corresponding to the first dam layer  201 , thereby avoiding that the distance between the layers the second dam layer  202  and the corresponding film layer is too large in the direction from the array substrate  10  to the dam structure  20 , and preventing the distance between the upper surfaces of the plurality of dam layers and the upper surfaces of the plurality of film layers from being too large. 
     In one embodiment, as shown in  FIG.  3   , a plurality of the dam layers on the second dam layer  202  are also in the grooves. Specifically, in combination with the above description, it can be seen that the side of the first groove  401  in this embodiment can surround the second dam layer  202  and the plurality of dam layers on the second dam layer. That is, the size of the first groove  401  may be greater than or equal to the overall size of the second dam layer  202  and the multiple dam layers on the second dam layer  202  in the direction from the array substrate  10  to the dam structure  20 , 
     Similarly, on the basis that the side of the second dam layer  202  does not exceed the side of the first dam layer  201 , the second dam layer  202  and the plurality of the dam layers on the second dam layer  202  in this embodiment are in the first groove  401 . In combination with the above description, the risk of the multiple film layers used to form the second dam layer  202  and the plurality of dam layers on the second dam layer  202  overflowing outside the first groove  401  can be reduced during the process of forming the second dam layer  202  and the plurality of dam layers on the second dam layer  202 , thereby reducing the risk of forming the second dam layer  202  and the plurality of dam layers located on the second dam layer  202 , and improving the working reliability of the dam structure  20 . Similarly, the shape of the first groove  401  is not limited here, and it needs to meet the requirement of avoiding the thin film used to form the second dam layer  202  and the excessive amount on the second dam layer  202  from overflowing to the outside of the first groove  401  during the fabrication process. 
     In one embodiment, as shown in  FIG.  4   , among the plurality of dam layers on the first dam layer  201 , at least one of the dam layers is provided with a groove, and the groove is provided with at least one of the dam layers therein. Specifically, among the plurality of dam layers on the first dam layer  201 , at least one of the dam layers is provided with a second groove  402 , and the second groove  402  is provided with at least one of the dam layers. That is, the second groove  402  may be opened in any one of the dam layers except the first dam layer  201  and the dam layer located on the top layer. 
     Similarly, the shape of the second groove  402  is not limited here, and it needs to meet the requirement of preventing the film used to form the dam layer in the second groove  402  from overflowing to outside the second groove  402 . In the same way, in the direction from the array substrate  10  to the dam structure  20  in this embodiment, the distance from the side of the dam layer with the second groove  402  close to the array substrate  10  to the bottom of the second groove  402  may be greater than or equal to the size of the film layer corresponding to the dam layer on which the second groove  402  is formed, so as to avoid the distance between the dam layer located in the second groove  402  and the corresponding film layer is too large, to avoid the distance between the upper surfaces of the film layers and the upper surface of multiple dam layers is too large. Similarly, when part of the dam layer is provided in the second groove  402 , the dam layer on the second groove  402  can extend into the second groove  402 , but the side of the dam layer on the second groove  402  may not exceed the side of the second groove  402  to avoid the film used to form the dam on the second groove  402  from overflowing to the side of the second groove  402 . 
     It can be understood that, compared with the embodiment shown in  FIG.  3   , in this embodiment, in addition to the first groove  401 , a second groove  402  is also provided in at least one of the dam layers located on the first dam layer  201 . That is, under the premise that multiple layers of the dam layer are provided in the first groove  401  and the second groove  402 , in this embodiment, due to the presence of the second groove  402 , the size of the first groove  401  in the direction from the array substrate  10  to the dam structure  20  can be set less, which can avoid spending more time on etching more materials used to form the first groove  401  as shown in  FIG.  3   , which improves the fabrication efficiency of the display panel  100 . 
     In one embodiment, in the cross section of the display panel  100 , the width of the side of the dam structure  20  away from the array substrate  10  is greater than or equal to 6 micrometers. In combination with the above description, as shown in  FIGS.  1 - 4   , a light-emitting layer  40  may be provided between two adjacent pixel defining portions  3051 . When the light-emitting layer  40  is formed by evaporation, the dam structure  20  and the plurality of support portions located on the plurality of pixel defining portions  3051  can support the photomask so that the light-emitting material is deposited on the plurality of pixel defining portions  3051  by the via holes defined in the photomask. 
     It is understandable that on the basis that the width of the second dam layer  202  is less than or equal to the width of the first dam layer  201 . In this embodiment, the size of the upper surface of the dam structure  20  in the direction from the display area  01  to the non-display area  02  is set to be greater than or equal to 6 micrometers, which can make the size of the upper surface of the dam structure  20  large enough to better control the mask process and further reduce the light, thereby reducing a risk of scratching the array substrate  10  when the cover is resting on the non-display area  02 . Of course, the minimum size of the upper surface of the dam structure  20  in the direction from the display area  01  to the non-display area  02  can also be set in combination with the sizes of the upper surfaces of multiple film layers. 
     Furthermore, the constituent material of the plurality of dam layers is the same as the constituent material of the organic layer group  30 . Specifically, the display area  01  comprises a light-transmitting area, an optical device and a plurality of transparent conductive layers arranged in the light-transmitting area. A set of organic layers is provided between two adjacent transparent conductive layers  30 , the constituent material of the organic layer group  30  comprises an insulating material, and the film layer in the organic layer group  30  is used to insulate the corresponding two transparent conductive layers. It can be seen in combination with the above description that because the multiple film layers in the display area  01  are formed by at least one process. Correspondingly, the multiple dam layers in the non-display area  02  are also formed by at least one process. Each of the dam layers can be formed by at least one process and the corresponding film layer is fabricated at the same time. It is understandable that in this way, multiple dam layers can be formed at the same time as the organic layer group  30  is formed, which improves the fabrication efficiency of the display panel  100 . 
     Furthermore, the constituent materials of the plurality of the dam layers and the constituent materials of the organic layer group  30  may be organic materials. It can be understood that due to the strong fluidity of organic materials, in the process of forming multiple dam layers and organic layer groups  30 , organic materials will overflow from the center to the side, so at least an angle between the side of the dam layer and the bottom near the array substrate  10  may be an acute angle. Similarly, the angle between the side of at least one film layer and the bottom near the array substrate  10  may be an acute angle. It should be noted that this is determined by the characteristics of organic materials and is not the original intention of this embodiment. On the contrary, at least one of the sides of the dam layer and the bottom of the array substrate  10  are clamped. The angle presented as an acute angle will cause the area of the side of the dam layer to increase. In the process of forming the dam layer, it will promote the overflow of the film forming the dam layer in the direction close to the bottom  10 , which is not conducive to the production of related embodiments in this application. 
     In one embodiment, as shown in  FIG.  5   , the dam structure  20  further comprises at least a first overflow layer  206 . In at least one set of two adjacent dam layers, the overflow layer  206  is far away from the wall. The side portion of the dam layer of the array substrate  10  extends at least to the side portion of the dam layer close to the array substrate  10 . Based on the above description, it can be seen that the organic material has strong fluidity, so the overflow layer  206  may be formed on the sides of the two adjacent dam layers. It should be noted that this is determined by factors such as the characteristics of organic materials and process accuracy, and is not the original intention of this embodiment. On the contrary, the existence of the overflow layer  206  will cause the corresponding dam layer to be in the array. The size in the direction from the substrate  10  to the dam structure  20  is reduced, which is actually not conducive to the implementation of the related embodiments in this application. It is understandable that it is stated here that the above-mentioned dam structure  20  including the above-mentioned overflow layer  206  caused by the above-mentioned uncontrollable reasons also belongs to the protection scope of the present application. 
     It should be noted that for the two adjacent dam layers, if the side of the dam layer located above and the side portion of the dam layer located below are closer in the fabrication process, the film used for forming the upper dam layer will overflow to the lower dam layer to form the overflow layer  206 . Even if the side of the upper dam layer and the side of the lower dam layer are produced during the production process, the distance between the two parts is relatively long, and the distance between the two here may not be less than 1.5 micrometers, but due to process accuracy or other external interference, the existence of the overflow layer  206  may also be caused. Specifically, the overflow layer  206  extends from the side of the second dam layer  202  to the side of the first dam layer  201  as an example for illustration. According to the above description, it can be seen that the constituent material of the overflow layer  206  and the constituent material of the second dam layer  202  may be the same. 
     The present application provides a fabrication method for a display panel. The display panel comprises a display area and a non-display area surrounding the display area. As shown in  FIG.  7   , the fabrication method for the display panel comprises the following steps and one of the combinations between the following steps, but not limited to. 
     Step S 1 : providing an array substrate. 
     Herein, the array substrate may comprise but is not limited to one layer, the array substrate may comprise a circuit layer, and the constituent material of the circuit layer may comprise a metal material. 
     Step S 2 : forming a first dam layer on the array substrate and in the non-display area, and forming first film layer in the same layer of the first dam layer on the array substrate and in the display area. 
     Herein, the display area comprises a light-transmitting area, an optical device and a transparent conductive layer arranged in the light-transmitting area. The first film layer may be located on the transparent conductive layer, and the constituent material of the first film layer comprises an insulating material, and the first film layer is used to insulate the transparent conductive layer and other conductive film layers. Specifically, the first dam layer and the first film layer may be simultaneously fabricated by patterning, and the constituent material of the first dam layer may be the same as the constituent material of the first film layer. It is understandable that in this way, the first dam layer can be formed at the same time as the first film layer is formed, which improves the fabrication efficiency of the display panel. 
     Step S 3 : forming a second dam layer on the first dam layer, and forming a second film of the same layer as the second dam layer on the first film layer, and a distance between the side of the second dam film and the side of the first dam layer is greater than or equal to 1.5 micrometers. 
     Similarly, the second dam film and the second film can be fabricated simultaneously by patterning, and the constituent material of the second dam film can be the same as the constituent material of the second film. It should be noted that setting the distance between the side of the second dam film and the side of the first dam layer to be greater than or equal to 1.5 micrometers can make the distance between the side of the second dam film and the side of the first dam layer is relatively large, which reduces the risk of overflowing of the second dam film to the first dam layer. 
     Step S 4 : processing the second dam film to form a second dam layer, and processing the second film to form a second film layer, the side of the second dam layer is not beyond the side of the first dam layer. 
     Herein, the second dam film and the second film can be dried naturally or artificially to form the second dam layer and the second film layer, so that the side of the second dam layer does not exceed the side of the first dam layer. In the same way, combined with the above description, it can be known that due to process accuracy or other external interference, an overflow layer may be formed, and the overflow layer extends from the side of the second dam layer to the side of the first dam layer. The constituent material of the overflow layer and the constituent material of the second dam layer may be the same. 
     The present application provides a mobile terminal. The mobile terminal comprises a terminal body and a display panel as described above, and the terminal body and the display panel are combined into one assembly. 
     In the present application, a display panel and a mobile terminal are provided, and the display panel comprises a display area and a non-display area surrounding the display area, and the display panel comprises: an array substrate; a dam structure, wherein the dam structure is on the array substrate and in the non-display area, the dam structure comprises a plurality of dam layers which are stacked layer by layer, and the plurality of dam layers comprise a first dam layer on the array substrate and a second dam layer on the first dam layer, and a width of the second dam layer is less than or equal to a width of the first dam layer in a cross-section of the display panel; an organic layer group on the array substrate and in the display area, and an absolute value of the difference between a thickness of the organic layer group and a thickness of the dam structure is less than or equal to a first predetermined threshold value; and a light-emitting layer on a side of the organic layer group away from the array substrate and in the display area. In the present application, the width of the second dam layer is set to be less than or equal to the width of the first dam layer, and the absolute value of the difference between the thickness of the organic layer group and the thickness of the dam structure is less than or equal to the first predetermined threshold value as a limitation, that is, the risk of overflow of the film used to form the second dam layer to the film used to form the first dam layer during the fabrication process can be reduced, thereby reducing a risk of the less thickness of the second dam layer, and improves the reliability of the dam structure. 
     The display panel and mobile terminal provided by the embodiments of the application are described in detail above. Specific examples are used in this article to explain the principles and implementations of the application. The descriptions of the above embodiments are only used to help understand the technology of the application. The solution and its core idea; those of ordinary skill in the art should understand that it is still possible to modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviates from the scope of the technical solution of each embodiment of the present application.