Patent Publication Number: US-2022231103-A1

Title: Display substrate and method for manufacturing same, and display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Chinese Patent Application No. 202110071115.X, filed on Jan. 19, 2021 and entitled “DISPLAY SUBSTRATE AND METHOD FOR MANUFACTURING SAME, AND DISPLAY DEVICE”, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technologies, and in particular to a display substrate and a method for manufacturing the same, and a display device. 
     BACKGROUND 
     Organic light-emitting diode (OLED) display substrates are widely used for their characteristics of self-luminance, wide viewing angle, wide color gamut, high contrast, low power consumption, fast response speed and the like. 
     In the related art, an OLED display substrate has a display region and a non-display region. The OLED display substrate includes a plurality of sub-pixels in the display region and an encapsulation film layer encapsulating the plurality of sub-pixels. The design of the encapsulation film layer can ensure the encapsulation performance of the OLED display substrate and improve the yield of the OLED display substrate. 
     SUMMARY 
     The present disclosure provides a display substrate and a method for manufacturing the same, and a display device. The technical solutions are as follows. 
     In an aspect, a display substrate is provided. The display substrate includes a display region and a non-display region surrounding the display region, wherein a portion, in the non-display region, of the display substrate includes: a base; a first material layer disposed on a side of the base, wherein the first material layer includes a first portion and a plurality of second portions, a thickness of the first portion being less than a thickness of the second portion, and the first portion being disposed between any adjacent two second portions; and a second material layer disposed on a side of the first material layer away from the base, wherein the second material layer covers the first material layer. 
     Optionally, the thickness of the first portion is 0. 
     Optionally, materials of the first material layer and the second material layer are both conductive materials. 
     Optionally, the first material layer and a gate of a thin film transistor of a sub-pixel, in the display region, of the display substrate are disposed in a same layer; and the second material layer and an anode of the sub-pixel, in the display region, of the display substrate are disposed in a same layer. 
     Optionally, the first material layer and a source-drain of a thin film transistor of a sub-pixel, in the display region, of the display substrate are disposed in a same layer; and the second material layer and an anode of the sub-pixel, in the display region, of the display substrate are disposed in a same layer. 
     Optionally, a common ground terminal voltage circuit trace, in the non-display region, of the display substrate includes the first material layer and the second material layer. 
     Optionally, the first material layer includes a titanium layer, an aluminum layer, and another titanium layer which are sequentially laminated in a direction going away from the base. 
     Optionally, the first material layer includes a molybdenum layer, an aluminum layer, and another molybdenum layer which are sequentially laminated in a direction going away from the base. 
     Optionally, a surface of the second material layer away from the first material layer is parallel to a bearing surface of the base. 
     Optionally, a shape of an orthographic projection of the second portion on the base is a rectangle. 
     Optionally, orthographic projections of the plurality of second portions on the base are uniformly arranged in an array. 
     Optionally, the plurality of second portions are uniformly arranged sequentially in a target direction, and the target direction is a pixel row direction or a pixel column direction of the display substrate. 
     Optionally, for each of the second portions, an area of an orthographic projection of a surface, away from the base, of the second portion on the base is less than an area of an orthographic projection of a surface, close to the base, of the second portion on the base. 
     Optionally, the orthographic projection of the surface, away from the base, of the second portion on the base is within the orthographic projection of the surface, close to the base, of the second portion on the base. 
     Optionally, the display substrate further includes: a third material layer and an encapsulation film layer which are disposed on a side of the second material layer away from the first material layer. 
     Optionally, the third material layer is a cathode layer of a sub-pixel of the display substrate. 
     In another aspect, a method for manufacturing a display substrate is provided. The display substrate includes a display region and a non-display region surrounding the display region, and the method includes: forming a first material layer on a side of a base, wherein the first material layer includes a first portion and a plurality of second portions, a thickness of the first portion being less than a thickness of the second portion, and the first portion being disposed between any adjacent two second portions; and forming a second material layer on a side of the first material layer away from the base, wherein the second material layer covers the first material layer. 
     Optionally, forming the first material layer on the side of the base includes: forming a first material film on the side of the base; and patterning the first material film to obtain the first material layer. 
     Optionally, the thickness of the first portion is 0. 
     In yet another aspect, a display device is provided. The display device includes a power supply component and a display substrate connected to the power supply component, wherein the power supply component is configured to supply power to the display substrate; and the display substrate includes a display region and a non-display region surrounding the display region, and a portion, in the non-display region, of the display substrate includes: a base; a first material layer disposed on a side of the base, wherein the first material layer includes a first portion and a plurality of second portions, a thickness of the first portion being less than a thickness of the second portion, and the first portion being disposed between any adjacent two second portions; and a second material layer disposed on a side of the first material layer away from the base, wherein the second material layer covers the first material layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To describe the technical solutions in embodiments of the present disclosure or prior art more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and persons of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG. 1  is a schematic structural diagram of a non-display region of a display substrate in the related art; 
         FIG. 2  is a top view of a display substrate according to an embodiment of the present disclosure; 
         FIG. 3  is a schematic structural diagram of a non-display region of a display substrate according to an embodiment of the present disclosure; 
         FIG. 4  is a schematic structural diagram of a base and a first material layer, in a non-display region, of a display substrate according to an embodiment of the present disclosure; 
         FIG. 5  is a schematic structural diagram of a non-display region of another display substrate according to an embodiment of the present disclosure; 
         FIG. 6  is a top view of a non-display region of a display substrate according to an embodiment of the present disclosure; 
         FIG. 7  is a top view of a non-display region of another display substrate according to an embodiment of the present disclosure; 
         FIG. 8  is a schematic structural diagram of a non-display region of yet another display substrate according to an embodiment of the present disclosure; 
         FIG. 9  is a top view of another display substrate according to an embodiment of the present disclosure; 
         FIG. 10  is a schematic structural diagram of a non-display region of still a further display substrate according to an embodiment of the present disclosure; 
         FIG. 11  is a flowchart of a method for manufacturing a display substrate according to an embodiment of the present disclosure; 
         FIG. 12  is a flowchart of another method for manufacturing a display substrate according to an embodiment of the present disclosure; and 
         FIG. 13  is a schematic structural diagram of a display device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in combination with the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are only part but not all of the embodiments of the present disclosure. All other embodiments derived by persons of ordinary skill in the art without creative efforts based on the embodiments in the present disclosure are within the protection scope of the present disclosure. 
     In the related art, referring to  FIG. 1 , the portion, in a non-display region, of an OLED display substrate includes a base  1 ′, and a first material layer  2 ′ and a second material layer  3 ′ which are laminated in sequence on a side of the base  1 ′. If the preparation accuracy of the first material layer  2 ′ and the second material layer  3 ′ is low (for example, an interface between the first material layer  2 ′ and the second material layer  3 ′ is not smooth and uneven), peeling may occur between the first material layer  2 ′ and the second material layer  3 ′. As a result, a water and oxygen path may be formed at the interface between the first material layer  2 ′ and the second material layer  3 ′, and the OLED display substrate has poor encapsulation performance in the non-display region, resulting in grow dark spots (GDS). 
     When the OLED display substrate is applied to a display device, a dark spot appears at the position of the grow dark spot of the display substrate when the display device displays an image. That is, the grow dark spots generated by the OLED display substrate cause the display device to fail, and the yield of the display device is low. 
       FIG. 2  is a top view of a display substrate according to an embodiment of the present disclosure. Referring to  FIG. 2 , it can be seen that the display substrate  100  may include a display region  10  and a non-display region  20  surrounding the display region  10 .  FIG. 3  is a schematic structural diagram of a portion, in a non-display region, of a display substrate according to an embodiment of the present disclosure. Referring to  FIG. 3 , it can be seen that the portion, in the non-display region  20 , of the display substrate  100  may include: a base  1 , a first material layer  2  and a second material layer  3 . 
     The first material layer  2  is disposed on a side of the base  1 . The second material layer  3  is disposed on a side of the first material layer  2  away from the base  1 , and the second material layer  3  covers the first material layer  2 . That is, the base  1 , the first material layer  2  and the second material  3  are laminated in sequence. 
     In the embodiment of the present disclosure, the first material layer  2  being disposed on a side of the base  1  refers to that an overall pattern layer of the first material layer  2  is disposed on a side of the base  1 , instead of indicating an absolute positional relationship of partial structures. The positional relationship between other pattern layers is similar to the above, and details are not repeated here. 
     Referring to  FIG. 3 , it can be seen that the first material layer  2  may include a first portion  21  and a plurality of second portions  22 . The thickness of the first portion  21  is less than the thickness of the second portion  22 , and the first portion  21  is disposed between any adjacent two second portions  22 . 
     Here, the second material layer  3  covering the first material layer  2  refers to that the second material layer  3  covers the first portion  21  and the plurality of second portions  22  of the first material layer  2 , and the second material layer  3  may fill a target region. The target region is formed by adjacent side faces of two adjacent second portions  22  and the face of the first portion  21  close to the second material layer  3 . 
     The second material layer  3  is in contact with not only the side of the second portion  22  close to the second material layer  3  and the side of the first portion  21  close to the second material layer  3 , but also the sidewall of the second portion  22 . Therefore, the contact area and the bonding force between the first material layer  2  and the second material layer  3  are increased, so that the first material layer  2  and the second material layer  3  are not easily peeled from each other. Further, the water and oxygen path at the interface between the first material layer  2  and the second material layer  3  can be prevented from forming, thereby preventing grow dark spots from generating on the display substrate, and ensuring the display effect of the display device. 
     In summary, the embodiment of the present disclosure provides a display substrate. The thickness of the first portion of the first material layer in the non-display region of the display substrate is less than the thickness of the second portion, so that the second material layer is in contact with the sidewall of the second portion. Therefore, the contact area and the bonding force between the second material layer and the first material layer can be increased, and the first material layer and the second material layer are prevented from peeling from each other. Further, the water and oxygen path at the interface between the first material layer and the second material layer can be prevented from forming, thereby preventing grow dark spots from generating on the display substrate, and ensuring the yield and display effect of the display device. 
     Optionally, the base  1  may be a flexible base. For example, the material of the base  1  may be polyimide (PI), so that the base  1  can be bent or bent to a specific angle according to actual requirements. Therefore, the display substrate  100  is a flexible display substrate or a curved display substrate. Certainly, the base  1  may also be made of other materials (for example, the base  1  may be a rigid base), which is not limited in the embodiment of the present disclosure. 
     In the case that the base  1  is a flexible base, the base  1  may include a first organic flexible layer, a second organic flexible layer, and an inorganic barrier layer disposed between the first organic flexible layer and the second organic flexible layer. The materials of the first organic flexible layer and the second organic flexible layer include polyimide, and the material of the inorganic barrier layer includes at least one of silicon nitride and silicon oxide. In such a design, not only the toughness of the base  1  can be improved, but also the encapsulation performance of the display substrate  100  is improved. 
     Optionally, the thickness of the first portion  21  may be 0. That is, referring to  FIG. 4 , the first portion  21  may be a gap. Alternatively, the thickness of the first portion  21  is greater than 0. That is, referring to  FIG. 3 , the first portion  21  may be a groove relative to the second portion  22 . 
     Referring to  FIG. 5 , in the case that the first portion  21  is a gap, the second material layer  3  covering the first material layer  2  refers to that the second material layer  3  covers the plurality of second portions  22  of the first material layer  2  and fills the gaps. Referring to  FIG. 3 , in the case that the first portion  21  is a groove relative to the second portion  22 , the second material layer  3  covering the first material layer  2  refers to that the second material layer  3  covers the plurality of second portions  22  of the first material layer  2  and fills the grooves. 
     As shown in  FIG. 3  to  FIG. 5 , the first material layer  2  includes the plurality of second portions  22 , and a first portion  21  is disposed between any two adjacent second portions  22 . Therefore, the plurality of second portions  22  are disposed to form the plurality of first portions  21  (gaps or grooves). The second material layer  3  covers the first material layer  2  and fills the target region. 
     In the embodiment of the present disclosure, the manufacturing process of the first material layer  2  may include: forming a first material film on a side of the base  1 , and patterning the first material film to acquire the first material layer  2 . The patterning treatment may include: photoresist coating, exposure, development, etching, and photoresist removal. 
     The thickness of the first portion  21  of the first material layer  2  is controlled by controlling the etching duration. The thickness of the first portion  21  is negatively correlated to the etching duration. That is, the longer the etching duration is, the less the thickness of the first portion  21  is; and the shorter the etching duration is, the greater the thickness of the first portion  21  is. 
     In addition, in order to facilitate the design and manufacture of a mask used during exposure, the sizes of the plurality of second portions  22  may be the same. When there are a large number of the second portions  22 , the size of the second portion  22  is small, so that the first material layer  2  can include more first portions  21 , and the contact area and the bonding force between the second material layer  3  and the first material layer  2  are increased. Therefore, the number and size of the second portions  22  and the width of the first portion  21  between any two adjacent second portions  22  can be determined according to an actual situation, which is not limited in the embodiment of the present disclosure. 
     In the embodiment of the present disclosure, the materials of the first material layer  2  and the second material layer  3  may both be conductive materials. Certainly, the first material layer  2  and the second material layer  3  may also be made of other materials as long as the first material layer  2  and the second material layer  3  are adjacent to each other. 
     In the embodiment of the present disclosure, the portion, in the display region  10 , of the display substrate  100  includes the base  1  and a plurality of sub-pixels disposed on a side of the base  1 . Each sub-pixel may include a pixel circuit and a light-emitting unit. The pixel circuit may include at least one thin film transistor. The thin film transistor may include a gate, a source, and a drain. The light-emitting unit may include an anode layer, a light-emitting layer and a cathode layer, and the anode layer may be electrically connected to the drain. 
     Optionally, film layers of the plurality of sub-pixels include a first inorganic layer, a first metal layer, an insulating layer, a second metal layer, a second inorganic layer, an anode layer, a light-emitting layer and a cathode layer which are sequentially laminated in a direction going away from the base  1 . The first metal layer may include the gate of the thin film transistor, and the second metal layer may include the source and the drain of the thin film transistor. 
     In the embodiment of the present disclosure, the first material layer  2  may be disposed in the same layer as the gate of the thin film transistor of the sub-pixel, in the display region  10 , of the display substrate  100 . The second material layer  3  may be disposed in the same layer as the anode layer of the sub-pixel, in the display region  10 , of the display substrate  100 . That is, the first material layer  2  and the gate of the thin film transistor of the sub-pixel of the display substrate  100  in the display region  100  may be prepared from the same material by the same mask patterning process. The second material layer  3  and the anode layer of the sub-pixel of the display substrate  100  in the display region  10  may be prepared from the same material by the same mask patterning process. 
     Alternatively, the first material layer  2  may be disposed in the same layer as the source and the drain of the thin film transistor of the sub-pixel, in the display region  10 , of the display substrate  100 . The second material layer  3  may be disposed in the same layer as the anode layer of the sub-pixel, in the display region  10 , of the display substrate  100 . That is, the first material layer  2  and the source and the drain of the thin film transistor of the sub-pixel of the display substrate  100  in the display region  10  may be prepared from the same material by the same mask patterning process. The second material layer  3  and the anode layer of the sub-pixel of the display substrate  100  in the display region  10  may be prepared from the same material by the same mask patterning process. 
     It should be noted that since the source and the drain of the thin film transistor of the sub-pixel in the display region  10  are disposed in the same layer as a data line in the display region  10 , in the case that the first material layer  2  is disposed in the same layer as the source and the drain, the first material layer  2  and the data line are also disposed in the same layer. That is, the first material layer  2 , the source and the drain, and the data line are prepared from the same material by the same mask patterning process. 
     In addition, the second material layer  3  is disposed in the same layer as the anode layer of the sub-pixel, in the display region  10 , of the display substrate  100 , and the material of the anode layer of the sub-pixel may generally be indium tin oxide (ITO). Therefore, the material of the second material layer  3  may also be ITO. Certainly, the second material layer  3  and the anode layer of the sub-pixel may also be made of other materials, which is not limited in the embodiment of the present disclosure. 
     Optionally, the first material layer  2  may include a titanium layer, an aluminum layer, and another titanium layer which are sequentially laminated in a direction going away from the base  1 . Alternatively, the first material layer  2  may include a molybdenum layer, an aluminum layer, and another molybdenum layer which are sequentially laminated in the direction going away from the base  1 . That is, the first material layer  2  may be a laminated structure of titanium, aluminum and titanium or of molybdenum, aluminum and molybdenum. Of course, the first material layer  2  may also be made of other materials, which is not limited in the embodiment of the present disclosure. 
     In the embodiment of the present disclosure, the shape of the orthographic projection of the second portion  22  on the base  1  may be a rectangle. Alternatively, the shape of the orthographic projection of the second portion  22  on the base  1  may be a circle. In the case that the shape of the orthographic projection of the second portion  22  on the base  1  is a rectangle, the shape of the second portion  22  may be a cube. In the case that the shape of the orthographic projection of the second portion  22  on the base  1  is a circle, the shape of the second portion  22  may be a cylinder. 
     Of course, the second portion  22  may also be of other shapes. For example, the shape of the second portion  22  is a triangular prism, and the like, which is not limited in the embodiment of the present disclosure. In the case that the shape of the second portion  22  is a triangular prism, the shape of the orthographic projection of the second portion  22  on the base may be a triangle. 
     In the embodiment of the present disclosure, the plurality of second portions  22  included in the first material layer  2  may be arranged in a plurality of ways. 
     As an optional implementation, referring to  FIG. 6 , the orthographic projections of the plurality of second portions  22  on the base  1  are uniformly arranged in an array. That is, a plurality of second portions  22  are disposed in both the pixel row direction X and the pixel column direction Y of the display substrate  100 , and each second portion  22  has at least two other adjacent second portions  22 . Each second portion  22  corresponds to at least two first portions  21 , such that the contact area and the bonding force between the first material layer  2  and the second material layer  3  are further increased. 
     Optionally, in the case that the orthographic projections of the plurality of second portions  22  on the base  1  are uniformly arranged in an array, the at least two first portions  21  corresponding to each second portion  22  may be connected, that is, the first portions  21  may be a whole. 
     As another optional implementation, the plurality of second portions  22  may be uniformly arranged in sequence in a target direction. The target direction may be the pixel row direction X or the pixel column direction Y of the display substrate. 
     Optionally, referring to  FIG. 7 , in the case that the plurality of second portions  22  are arranged in the pixel row direction X, one second portion  22  is disposed in the pixel column direction Y, and a plurality of second portions  22  are disposed in the pixel row direction X. Of course, when the plurality of second portions  22  are arranged in the pixel column direction Y, there is one second portion  22  in the pixel row direction X, and a plurality of second portions  22  are disposed in the pixel column direction Y. 
     In the embodiment of the present disclosure, for each second portion  22 , the area of the orthographic projection of the surface of the second portion  22  away from the base  1  on the base  1  may be less than the area of the orthographic projection of the surface of the second portion  22  close to the base  1  on the base  1 . In addition, the orthographic projection of the surface of the second portion  22  away from the base  1  on the base  1  may be within the orthographic projection of the surface of the second portion  22  close to the base  1  on the base  1 . 
     As shown in  FIG. 8 , the shape of the second portion  22  may be a quadrangular frustum, and the top surface of the quadrangular frustum is parallel to the bearing surface of the base  1 . The area of the top surface of the quadrangular frustum is less than the area of the bottom surface of the quadrangular frustum, to facilitate the processing of the first material layer  2 . In addition, the shape of the second portion  22  is a quadrangular frustum, such that the area of the side surface of the second portion  22  can be increased, which can further increase the contact area and the bonding force between the first material layer  2  and the second material layer  3 . 
       FIG. 9  is a top view of another display substrate according to an embodiment of the present disclosure. Referring to  FIG. 9 , the portion, in the non-display region  20 , of the display substrate  100  may include a common ground terminal voltage (voltage series, (VSS)) circuit trace a. The common ground terminal voltage circuit trace a may include the first material layer  2  and the second material layer  3 . That is, the first material layer  2  and the second material layer  3  may serve as the common ground terminal voltage circuit traces a to provide common ground terminal voltage signals for the cathode layer of the sub-pixel. Optionally,  FIG. 3 ,  FIG. 5 , and  FIG. 8  may be all cross-sectional views of  FIG. 9  in the AA direction. 
     Only three common ground terminal voltage circuit traces a are drawn in the non-display region on the left side of the display region  10  in  FIG. 9 . In practice, the common ground terminal voltage circuit traces a may be disposed in all of the non-display region on the upper side of the display region  10 , the non-display region on the right side of the display region  10 , and the non-display region on the lower side of the display region  10 . In addition, only one common ground terminal voltage circuit trace may be disposed in the non-display region on each side of the display region  10 . The position and number of the common ground terminal voltage circuit trace a are not limited in the embodiment of the present disclosure, as long as the common ground terminal voltage circuit trace a can provide the signal for the cathode layer of the sub-pixel. 
     In the embodiment of the present disclosure, referring to  FIG. 8 , the portion, in the non-display region  20 , of the display substrate  100  further includes an inorganic film layer  4  disposed between the first material layer  2  and the base  1 . In addition, referring to  FIG. 10 , the portion, in the non-display region  20 , of the display substrate  100  further includes: a third material layer  5  and an encapsulation film layer  6  which are disposed on the side of the second material layer  3  away from the first material layer  2 . The encapsulation film layer  6  may be configured to prevent water vapor from entering the display region of the display substrate  100 , to enhance the encapsulation performance of the display substrate  100 . 
     Optionally, the inorganic film layer  4  may be a first inorganic layer, an insulating layer, and a second inorganic layer in the display region  10  of the display substrate  100 . That is, the first inorganic layer, the insulating layer, and the second inorganic layer may be disposed in the non-display region  20  in addition to the display region  10 . 
     In addition, the third material layer  5  may be formed into a film by an evaporation process. The film formation by the evaporation process refers to that an evaporation material is heated under a certain vacuum condition, so that the evaporation material is melt or sublimed into vapor composed of atoms, molecules or groups of atoms, and the vapor is then condensed on the surface of the base  1  to form the film. During the evaporation process, the evaporation material is basically formed into the film in a direction perpendicular to the bearing surface of the base  1 . The third material layer  5  may be formed by evaporation in a large are, or may be formed by patterning evaporation with a mask. 
     Optionally, the third material layer  5  may be the cathode layer of the sub-pixel of the display substrate  100 . That is, the cathode layer of the sub-pixel may be disposed in the non-display region  20  in addition to the display region  10 . In addition, the third material layer  5  is in contact with the second material layer  3 , so that the first material layer  2  and the second material layer  3  which serve as the common ground terminal voltage circuit traces a can provide the common ground terminal voltage signals for the third material layer  5  (the cathode layer). 
     In summary, the embodiment of the present disclosure provides a display substrate. The thickness of the first portion of the first material layer in the non-display region of the display substrate is less than the thickness of the second portion, so that the second material layer is in contact with the sidewall of the second portion. Therefore, the contact area and the bonding force between the second material layer and the first material layer can be increased, to prevent the first material layer and the second material layer from peeling off each other. Further, a water and oxygen path can be prevented from forming at the interface between the first material layer and the second material layer, thereby preventing grow dark spots from generating on the display substrate, and ensuring the yield and display effect of the display device. 
       FIG. 11  is a flowchart of a method for manufacturing a display substrate according to an embodiment of the present disclosure. Referring to  FIG. 11 , the method may include the following steps. 
     In step S 11 , a first material layer is formed on a side of a base. 
     In the embodiment of the present disclosure, after the base  1  is acquired, the first material layer  2  may be formed on a side of the base  1 . The first material layer  2  may include a first portion  21  and a plurality of second portions  22 . The thickness of the first portion  21  is less than the thickness of the second portion  22 , and a first portion  21  is disposed between any two adjacent second portions  22 . 
     In step S 12 , a second material layer is formed on a side of the first material layer away from the base. 
     In the embodiment of the present disclosure, after the first material layer  2  is formed, the second material layer  3  may be formed on the side of the first material layer  2  away from the base  1 . The second material layer  3  may cover the first material layer  2 . 
     In addition, covering the first material layer  2  by the second material layer  3  refers to that the second material layer  3  covers the first portion  21  and the plurality of second portions  22  of the first material layer  2 , and the second material layer  3  can fill the target region. 
     The second material layer  3  is in contact with not only the side of the second portion  22  close to the second material layer  3  and the side of the first portion  21  close to the second material layer  3 , but also the sidewall of the second portion  22 . Therefore, the contact area and the bonding force between the first material layer  2  and the second material layer  3  are increased, so that the first material layer  2  and the second material layer  3  are not easily peeled off. Further, a water and oxygen path can be prevented from forming at the interface between the first material layer  2  and the second material layer  3 , thereby preventing grow dark spots from generating on the display substrate, and ensuring the display effect of the display device. 
     In summary, the embodiment of the present disclosure provides a method for manufacturing a display substrate. The thickness of the first portion of the first material layer in the non-display region of the display substrate manufactured by the method is less than the thickness of the second portion, so that the second material layer is in contact with the sidewall of the second portion. Therefore, the contact area and the bonding force between the second material layer and the first material layer can be increased, and the first material layer and the second material layer are prevented from peeling off. Further, the water and oxygen path can be prevented from forming at the interface between the first material layer and the second material layer, thereby preventing grow dark spots from generating on the display substrate, and ensuring the yield and display effect of the display device. 
       FIG. 12  is a flowchart of another method for manufacturing a display substrate according to an embodiment of the present disclosure. Referring to  FIG. 12 , the method may include the following steps. 
     In step S 21 , an inorganic film layer is formed on a side of a base. 
     In the embodiment of the present disclosure, the base  1  may be acquired at first, and the inorganic film layer  4  may be formed on a side of the base  1 . The inorganic film layer  4  may be formed in a process of forming the sub-pixel of the display substrate. The inorganic film layer  4  may include a portion disposed in the display region and a portion in the non-display region. 
     Optionally, the base  1  may be a flexible base or a rigid base. In the case that the base  1  is a flexible base, the flexible base is formed on a glass substrate before the display substrate is formed. The glass substrate plays a supporting role in the manufacturing process of the display substrate. After the display substrate is manufactured, the glass substrate and the flexible base also need to be peeled off, to support flexible characteristics of the display substrate. 
     In step S 22 , a first material layer is formed on a side of the inorganic film layer away from the base. 
     In the embodiment of the present disclosure, the process of forming the first material layer  2  may include: forming a first material film on a side of the base  1 , and patterning the first material film to acquire the first material layer  2 . The patterning treatment may include: photoresist coating, exposure, development, etching, and photoresist removal. The thickness of the first portion  21  of the first material layer  2  is controlled by controlling etching duration. 
     Optionally, the first material film may be formed through a sputtering process, and the first material film may be etched through dry etching to form the first material layer  2 . 
     The first material layer  2  may include the first portion  21  and the plurality of second portions  22 . The thickness of the first portion  21  is less than the thickness of the second portion  22 , and a first portion  21  is disposed between any two adjacent second portions  22 . 
     In step S 23 , a second material layer is formed on a side of the first material layer away from the inorganic film layer. 
     In the embodiment of the present disclosure, after the first material layer  2  is formed, the second material layer  3  may be formed on the side of the first material layer  2  away from the base  1 . The second material layer  3  may cover the first material layer  2 . 
     Optionally, the second material layer  3  may be disposed in the same layer as the anode layer of the sub-pixel, that is, the second material layer  3  and the anode layer of the sub-pixel are prepared from the same material by the same patterning process. The manufacturing process of the second material layer  3  and the anode layer may include: forming a second material film on the side of the first material layer  2  away from the base  1 , and patterning the second material film to acquire the second material layer and the anode layer. 
     Optionally, the second material film may be formed through the sputtering process, and the second material film may be etched through the dry etching. 
     Covering the first material layer  2  by the second material layer  3  refers to that the second material layer  3  covers the first portion  21  and the plurality of second portions  22  of the first material layer  2 , and the second material layer  3  can fill the target region. 
     The second material layer  3  is in contact with not only the side of the second portion  22  close to the second material layer  3  and the side of the first portion  21  close to the second material layer  3 , but also the sidewall of the second portion  22 . Therefore, the contact area and the bonding force between the first material layer  2  and the second material layer  3  are increased, so that the first material layer  2  and the second material layer  3  are not easily peeled off. Further, the water and oxygen path can be prevented from forming at the interface between the first material layer  2  and the second material layer  3 , thereby preventing grow dark spots from generating on the display substrate, and ensuring the display effect of the display device. 
     In step S 24 , a third material layer is formed on a side of the second material layer away from the first material layer. 
     In the embodiment of the present disclosure, after the second material layer  3  is formed, the third material layer  5  may be formed on the side of the second material layer away from the first material layer  2 . The third material layer  5  may be in contact with the second material layer  3 . 
     Optionally, the first material layer  2  and the second material layer  3  may form a common ground terminal voltage circuit trace of the display substrate. The first material layer  2  and the second material layer  3  may serve as the common ground terminal voltage circuit traces to provide common ground terminal voltage signals for the third material layer  5  (the cathode layer of the sub-pixel). 
     In step S 25 , an encapsulation film layer is formed on a side of the third material layer away from the second material layer. 
     In the embodiment of the present disclosure, after the third material layer  5  is formed, the encapsulation film layer  6  may be formed on the side of the third material layer  5  away from the second material layer  3 . The encapsulation film layer  6  may be configured to encapsulate the display region of the display substrate to prevent water vapor from entering the display region, so as to ensure the encapsulation performance of the display substrate. 
     In summary, the embodiment of the present disclosure provides a method for manufacturing a display substrate. The thickness of the first portion of the first material layer in the non-display region of the display substrate manufactured by the method is less than the thickness of the second portion, so that the second material layer is in contact with the sidewall of the second portion. Therefore, the contact area and the bonding force between the second material layer and the first material layer can be increased, and the first material layer and the second material layer are prevented from peeling off. Further, the water and oxygen path is prevented from forming at the interface between the first material layer and the second material layer, thereby preventing grow dark spots from generating on the display substrate, and ensuring the yield and display effect of the display device. 
       FIG. 13  is a schematic structural diagram of a display device according to an embodiment of the present disclosure. Referring to  FIG. 13 , the display device may include a power supply component and a display substrate connected to the power supply component. The display substrate may be the display substrate  100  in the above embodiment. The power supply component  200  may be configured to supply power to the display substrate  100 . 
     Optionally, the display substrate may be an OLED display substrate or a quantum dot light emitting diode (QLED) display substrate. That is, the display device includes, but is not limited to, the OLED display substrate, the QLED display substrate, and the like. 
     In addition, the display device may be a curved display device, a flexible display device, or a stretchable display device. The specific product type of the display device is not limited, and display device may be, for example, a mobile phone, a tablet computer, a display, a television, a painting screen, an advertising screen, electronic paper, a smart wearable device, a vehicle navigation device, and so on. 
     Since the display substrate has good encapsulation performance and long service life, the display device also has good product quality. 
     It should be noted that the relational terms such as “first” and “second” as used herein are merely used to distinguish a subject or an operation from another subject or operation, instead of requiring or implying any substantial relation or order between these subjects or operations. Moreover, the terms “include”, “comprise” or any variations thereof are intended to cover a nonexclusive inclusion, such that a process, a method, an item or a device including a series of elements not only includes these elements, but also includes other elements that are not set forth specifically, or also includes an inherent element of such a process, method, item or device. Without more limitations, the element defined by the phrase “including a . . . ” does not exclude the existence of other same elements in the process, method, item, or device that including such element. 
     Described above are merely optional embodiments of the present disclosure, and are not intended to limit the present disclosure. Within the spirit and principles of the disclosure, any modifications, equivalent substitutions, improvements, and the like are within the protection scope of the present disclosure.