Patent Publication Number: US-2022223668-A1

Title: Display substrate and method for manufacturing the same, display panel, and display apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase entry under 35 USC 371 of International Patent Application No. PCT/CN2021/076762, filed on Feb. 18, 2021, which claims priority to Chinese Patent Application No. 202010105939.X, filed on Feb. 20, 2020, which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technologies, and in particular, to a display substrate, a display panel, a display apparatus, and a method for manufacturing the display substrate. 
     BACKGROUND 
     Electroluminescent display apparatuses have become the mainstream development trend of current display apparatuses due to their advantages of self-luminescence, low power consumption, wide viewing angle, fast response speed, high contrast and the like. 
     At present, an inkjet printing (IJP) process is generally used to form a light-emitting layer in an opening region of a pixel defining layer. 
     SUMMARY 
     In one aspect, a display substrate is provided. The display substrate includes a base substrate, a plurality of first electrodes disposed on the base substrate, a first pixel defining layer disposed on the base substrate, a second pixel defining layer disposed on the base substrate and light-emitting layers disposed in a plurality of second opening regions. The first pixel defining layer includes a plurality of first opening regions, and each first opening region exposes at least a portion of a first electrode of the plurality of first electrodes. The second pixel defining layer includes the plurality of second opening regions, each second opening region corresponds to at least two first opening regions of the plurality of first opening regions, and orthogonal projections of the at least two first opening regions on the base substrate are located within an orthogonal projection of the second opening region on the base substrate. The light-emitting layers overspreads the plurality of second opening regions in a plane perpendicular to a thickness direction of the base substrate, respectively. 
     In some embodiments, a surface of the first electrode away from the base substrate is closer to the base substrate than a surface of the first pixel defining layer away from the base substrate. 
     In some embodiments, a surface of the first electrode away from the base substrate is as close to the base substrate as a surface of the first pixel defining layer away from the base substrate. 
     In some embodiments, a surface of the first electrode away from the base substrate is farther away from the base substrate than a surface of the first pixel defining layer away from the base substrate. 
     In some embodiments, the display substrate further includes a plurality of auxiliary patterns disposed between the base substrate and the plurality of first electrodes, and the first electrode is disposed on a surface of an auxiliary pattern away from the base substrate. 
     In some embodiments, an orthogonal projection of a surface of the auxiliary pattern away from the base substrate on the base substrate is located within an orthogonal projection of a surface of the auxiliary pattern proximate to the base substrate on the base substrate. 
     In some embodiments, the first electrode covers a surface of the auxiliary pattern away from the base substrate and side faces of the auxiliary pattern. 
     In some embodiments, an orthogonal projection of a surface of the first electrode away from the base substrate on the base substrate is located within an orthogonal projection of a surface of the first electrode proximate to the base substrate on the base substrate. 
     In some embodiments, the first pixel defining layer covers side faces of the first electrode. 
     In some embodiments, the first pixel defining layer is directly disposed on the base substrate, and the second pixel defining layer is disposed on a surface of the first pixel defining layer away from the base substrate; or the first pixel defining layer and the second pixel defining layer are both directly disposed on the base substrate. 
     In some embodiments, an orthographic projection of a surface of the first pixel defining layer proximate to the base substrate on the base substrate is located within an orthographic projection of a surface of the first pixel defining layer away from the base substrate on the base substrate; and an orthographic projection of a surface of the second pixel defining layer away from the base substrate on the base substrate is located within an orthographic projection of a surface of the second pixel defining layer proximate to the base substrate on the base substrate. 
     In some other embodiments, a material of the first pixel defining layer is the same as a material of the second pixel defining layer. 
     In some embodiments, a height of the second pixel defining layer is greater than a height of the first pixel defining layer, and the height of the first pixel defining layer and the height of the second pixel defining layer each refer to a dimension in the thickness direction of the base substrate. 
     In some embodiments, the second opening region corresponds to a row of first opening regions, and the row of first opening regions correspond to a same color; or the second opening region corresponds to a column of first opening regions, and the column of first opening regions correspond to a same color. 
     In some embodiments, the second opening region corresponds to part of first opening regions in a row of first opening regions, and the part of first opening regions correspond to a same color; or the second opening region corresponds to part of first opening regions in a column of first opening regions, and the part of first opening regions correspond to a same color. 
     In some embodiments, the display substrate further includes a second electrode disposed on the light-emitting layer; and one of the first electrode and the second electrode is an anode, and another is a cathode. 
     In another aspect, a display panel is provided. The display panel includes the display substrate as described in any of the above embodiments and an encapsulation layer encapsulating the display substrate. 
     In yet another aspect, a display apparatus is provided. The display apparatus includes the display panel as described in the above embodiment. 
     In yet another aspect, a method of manufacturing a display substrate is provided. The method includes: forming a plurality of first electrodes on a base substrate; forming a first pixel defining layer on the base substrate, the first pixel defining layer including a plurality of first opening regions, and each first opening region exposing at least a portion of a first electrode in the plurality of first electrodes; forming a second pixel defining layer on the base substrate, the second pixel defining layer including a plurality of second opening regions, each second opening region corresponding to at least two first opening regions in the plurality of first opening regions, and orthogonal projections of the at least two first opening regions on the base substrate being located within an orthogonal projection of the second opening region on the base substrate; and forming light-emitting layers in the second opening regions, the light-emitting layers overspreading the second opening regions in a plane perpendicular to a thickness direction of the base substrate, respectively. 
     In some embodiments, before forming the plurality of first electrodes on the base substrate, the method further includes forming a plurality of auxiliary patterns on the base substrate, a first electrode being disposed on an auxiliary pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe technical solutions in the present disclosure more clearly, accompanying drawings to be used in some embodiments of the present disclosure will be introduced briefly below. However, the accompanying drawings to be described below are merely accompanying drawings of some embodiments of the present disclosure, and a person of ordinary skill in the art can obtain other drawings according to these drawings. In addition, the accompanying drawings in the following description may be regarded as schematic diagrams, and are not limitations on actual sizes of products, actual processes of methods and actual timings of signals involved in the embodiments of the present disclosure. 
         FIG. 1  is a schematic structural diagram of a display apparatus, in accordance with some embodiments; 
         FIG. 2  is a schematic diagram showing a division of a region of a display panel, in accordance with some embodiments; 
         FIG. 3  is a schematic structural diagram of a display panel, in accordance with some embodiments; 
         FIG. 4  is a schematic structural diagram of another display panel, in accordance with some embodiments; 
         FIG. 5  is a schematic structural diagram of a display substrate, in accordance with some embodiments; 
         FIG. 6A  is a schematic sectional view of the display substrate in  FIG. 5  taken along the AA line; 
         FIG. 6B  is another schematic sectional view of the display substrate in  FIG. 5  taken along the AA line; 
         FIG. 7  is a schematic structural diagram of another display substrate, in accordance with some embodiments; 
         FIG. 8  is a schematic structural diagram of yet another display substrate, in accordance with some embodiments; 
         FIG. 9  is a sectional view of the display substrate in  FIG. 8  taken along the BB line; 
         FIG. 10  is another sectional view of the display substrate in  FIG. 8  taken along the BB direction; 
         FIG. 11  is yet another sectional view of the display substrate in  FIG. 8  taken along the BB direction; 
         FIG. 12  is a schematic structural diagram of yet another display substrate, in accordance with some embodiments; 
         FIG. 13A  is a schematic diagram showing a structure including auxiliary patterns and a planarization layer, in accordance with some embodiments; 
         FIG. 13B  is a schematic diagram showing another structure including auxiliary patterns and a planarization layer, in accordance with some embodiments; 
         FIG. 14  is a schematic flow diagram of a method for manufacturing a display substrate, in accordance with some embodiments; 
         FIG. 15  is a schematic diagram of forming auxiliary patterns on a base substrate, in accordance with some embodiments; 
         FIG. 16  is a schematic diagram of forming first electrodes on auxiliary patterns, in accordance with some embodiments; 
         FIG. 17  is a schematic diagram of forming a first pixel defining layer on first electrodes, in accordance with some embodiments; 
         FIG. 18  is a schematic diagram of forming a second pixel defining layer on a first pixel defining layer, in accordance with some embodiments; and 
         FIG. 19  is a schematic diagram of forming a light-emitting layer in a second opening region of a second pixel defining layer, in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Technical solutions in some embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings below. However, the described embodiments are merely some but not all embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure shall be included in the protection scope of the present disclosure. 
     Unless the context requires otherwise, throughout the description and the claims, the term “comprise” and other forms thereof such as the third-person singular form “comprises” and the present participle form “comprising” are construed as open and inclusive, i.e., “including, but not limited to”. In the description of the specification, the terms such as “one embodiment”, “some embodiments”, “exemplary embodiments”, “example”, “specific example”, and “some examples” are intended to indicate that specific features, structures, materials or characteristics related to the embodiment(s) or example(s) are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms do not necessarily refer to the same embodiment(s) or example(s). In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any suitable manner. 
     Hereinafter, the terms such as “first” and “second” are used for descriptive purposes only, and are not to be construed as indicating or implying the relative importance or implicitly indicating the number of indicated technical features. Thus, features defined by “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the term “a plurality of/the plurality of” means two or more unless otherwise specified. 
     The phrase “at least one of A, B and C” has the same meaning as the phrase “at least one of A, B or C”, and they both include the following combinations of A, B and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B and C. 
     The phrase “A and/or B” includes the following three combinations: only A, only B, and a combination of A and B. 
     In the description of some embodiments of the present disclosure, orientations or positional relationships indicated by the terms such as “center”, “upper”, “lower”, “front”, “behind”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings. They are used merely for convenience in describing the present disclosure and simplifying the description, but not to indicate or imply that the indicated apparatus or element must have a specific orientation, or be constructed and operated in a specific orientation, and thus they cannot be construed as a limitation of the present disclosure. 
     In the description of some embodiments, terms such as “coupled” and “connected” and their extensions may be used. For example, term “connected” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact with each other. As another example, term “coupled” may be used in the description of some embodiments to indicate that two or more components are in direct physical or electrical contact. The term “coupled” or “communicatively coupled”, however, may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content herein. 
     Some embodiments of the present disclosure provide a display apparatus. As shown in  FIG. 1 , the display apparatus includes a display panel  1 , a frame  2 , a cover glass  3 , a circuit board  4  and other electronic components. 
     A longitudinal section of the frame  2  is U-shaped. The display panel  1 , the circuit board  4  and other electronic components are all disposed in the frame  2 . The circuit board  4  is disposed behind the display panel  1 , and the cover glass  3  is disposed at a side of the display panel  1  away from the circuit board  4 . 
     The display apparatus may be an organic light-emitting diode (OLED) display apparatus, and in this case, the display panel  1  is an OLED display panel. The display apparatus may also be a quantum dot light-emitting diode (QLED) display apparatus, and in this case, the display panel  1  is a QLED display panel. 
     As shown in  FIG. 2 , seen from a position facing a display surface of the display panel, the display panel  1  has a display region  01  and a peripheral region  02  located on at least one side of the display region  01 .  FIG. 2  illustrates an example where the peripheral region  02  surrounds the display region  01 . The display region  01  includes a plurality of light-emitting regions  011  (each light-emitting region  011  corresponds to a sub-pixel) and a non-light-emitting region  012 . The plurality of light-emitting regions  011  include red light-emitting regions for emitting red light, blue light-emitting regions for emitting blue light, and green light-emitting regions for emitting green light. In some embodiments, as shown in  FIG. 2 , a column of red light-emitting regions R, a column of green light-emitting regions G and a column of blue light-emitting regions B are alternately arranged in sequence. In some other embodiments, an arrangement order of the red light-emitting regions R, the green light-emitting regions G and the blue light-emitting regions B may be changed. The peripheral region  02  is used for wiring, so that a plurality of sub-pixels in the display region  01  are connected to a gate drive circuit or a source drive circuit through wires. In addition, the gate drive circuit may be provided in the peripheral region  02  by using a gate on array (GOA) technique, so that a size of the peripheral region  02  may be reduced and a narrow bezel of the display apparatus may be realized. 
       FIGS. 3 and 4  are schematic structural diagrams of display panels. A difference between  FIG. 3  and  FIG. 4  mainly lies in that structures of thin film transistors in  FIG. 3  and  FIG. 4  are different. Since structures of light-emitting regions  011  in the display panel are basically repeated,  FIGS. 3 and 4  each only show part of a structure of a light-emitting region  011  in the display panel as examples. 
     As shown in  FIGS. 3 and 4 , the display panel  1  includes a display substrate  11 , and an encapsulation layer  12  for encapsulating the display substrate  11 . The encapsulation layer  12  may be an encapsulation film or an encapsulation substrate. 
     In a case where the encapsulation layer  12  is an encapsulation film, the number of layers of films for encapsulation included in the encapsulation layer  12  is not limited. The encapsulation layer  12  may include one layer of film for encapsulation, or may include two or more layers of films for encapsulation which are stacked. In some embodiments, the encapsulation layer  12  includes three layers of films for encapsulation stacked in the thickness direction of the base substrate. 
     In a case where the encapsulation layer  12  includes three layers of films for encapsulation stacked, a film for encapsulation located in an intermediate layer is made of an organic material, and films for encapsulation located on both sides are made of an inorganic material. 
     In some embodiments of the present disclosure, the organic material is not limited, which may be, for example, polymethyl methacrylate (PMMA). Similarly, the inorganic material is not limited, which may be, for example, one or more of silicon nitride (SiNx), silicon oxide (SiOx) or silicon oxynitride (SiOxNy). 
     On this basis, an inkjet printing (IJP) process may be used for fabricating the organic film for encapsulation in the intermediate layer. In addition, a chemical vapor deposition (CVD) process may be used for fabricating the inorganic films for encapsulation on both sides. 
     As shown in  FIGS. 3 and 4 , the display substrate  11  includes a base substrate  110 , and a plurality of light-emitting devices  120  disposed on the base substrate  110 . 
     It will be easily understood that the base substrate  110  may be a blank substrate, or a substrate with a film structure. 
     In some embodiments, the base substrate  110  includes a blank substrate  111 , and a plurality of pixel circuits disposed on the blank substrate  111 . 
     In some embodiments, the blank substrate  111  may be a flexible blank substrate or a rigid blank substrate. The flexible blank substrate  111  may be made of, for example, polyimide (PI), and the rigid blank substrate  111  may be made of, for example, glass. 
     The base substrate  110  further includes gate lines arranged in a direction on the blank substrate  111 , and data lines and common power lines insulated from and crossing the gate lines. The common power lines are generally parallel to the data lines. The plurality of sub-pixels may be defined with the gate lines and the data lines (and the common power lines) which are arranged crosswise. Each sub-pixel has a pixel circuit, and the pixel circuit is electrically connected to a light-emitting device  120  for driving the light-emitting device  120  to emit light. 
     The pixel circuit includes a plurality of thin film transistors and at least one capacitor, and each thin film transistor may have a top-gate structure or a bottom-gate structure. As shown in  FIG. 3 , in a case where the thin film transistor has a top-gate structure, the thin film transistor includes an active layer AL, a gate insulating layer GI, a gate metal layer GM (which forms a gate  112 ), an interlayer dielectric layer ILD and a source-drain metal layer SD (which forms a source  113  and a drain  114 ) that are disposed on the blank substrate  111  in sequence. As shown in  FIG. 4 , in a case where the thin film transistor has a bottom-gate structure, the thin film transistor includes a gate metal layer GM (which forms a gate  112 ), a portion of a gate insulating layer GI, an active layer AL and a source-drain metal layer SD (which forms a source  113  and a drain  114 ) that are disposed on the blank substrate  111  in sequence. 
     The active layer AL of the thin film transistor may be formed of amorphous silicon, monocrystalline silicon, polycrystalline silicon or oxide semiconductor. The active layer AL includes a channel region not doped with any impurity, and a source region and a drain region each formed by doping impurities on both sides of the channel region. The doped impurities vary with the type of the thin film transistor, and the doped impurities may be N-type impurities or P-type impurities. 
     The capacitor (not shown in  FIGS. 3 and 4 ) includes a first electrode plate and a second electrode plate, between which an interlayer insulating film as a dielectric is to provided. 
     A 2T1C structure in which the pixel circuit includes two thin film transistors (i.e., a switch thin film transistor and a drive thin film transistor) and a capacitor is taken as an example to describe electrical connection relationships inside and outside the pixel circuit below. Although each of  FIGS. 3 and 4  only shows structures and a connection relationship of the drive thin film transistor (i.e., a structure as showed in a dotted line circle in  FIGS. 3 and 4 ) and the light-emitting device  120 , a structure of the switch thin film transistor and its connection relationships with other components may be completely determined by those skilled in the art according to the description of the context. 
     A gate of the switch thin film transistor is connected to a gate line, a source of the switch thin film transistor is connected to a data line, and a drain of the switch thin film transistor is connected to a gate of the drive thin film transistor. A source of the drive thin film transistor is connected to a common power line, and a drain  114  of the drive thin film transistor is connected to a first electrode  121  of the light-emitting device  120  through a via hole. The first electrode plate of the capacitor is connected to the gate of the drive thin film transistor, and the second electrode plate of the capacitor is connected to the source of the drive thin film transistor. 
     The switch thin film transistor is turned on by a gate voltage applied to the gate line, thereby transmitting a data voltage applied to the data line to the drive thin film transistor. There is a certain difference between the data voltage transmitted from the switch thin film transistor to the drive thin film transistor and a common voltage applied from the common power line to the drive thin film transistor. A voltage equivalent to an absolute value of the difference is stored in the capacitor, and a current corresponding to the voltage stored in the capacitor flows into the light-emitting device  120  through the drive thin film transistor, so that the light-emitting device  120  emits light. 
     In some embodiments, as shown in  FIGS. 3 and 4 , the base substrate  110  further includes a planarization layer  115  disposed on the thin film transistors. 
     As shown in  FIGS. 3, 4 and 12 , the light-emitting devices  120  include the first electrodes  121 , light-emitting functional layers  122  and a second electrode  123  that are disposed on the base substrate  110  in sequence. One of the first electrode  121  and the second electrode  123  is an anode (for providing holes) and the other is a cathode (for providing electrons). The first electrode  121  and the second electrode  123  inject holes and electrons into the light-emitting functional layer  122 , respectively, and light is emitted when transitions of excitons generated by the combination of the holes and the electrons from an excited state to a ground state occur. 
     The first electrode  121  may be formed of a metal with high reflectivity, and the second electrode  123  may be formed of a transparent conductive film. In this case, light emitted by the light-emitting functional layer  122  is reflected by the first electrode  121  and then travels to the outside through the second electrode  123 . Thus, a top-emission light-emitting device is formed. However, the solution is not limited thereto. In a case where the first electrode  121  is formed of a transparent conductive film, and the second electrode  123  is formed of a metal with high reflectivity, a bottom-emission light-emitting device may be formed. Of course, in a case where the first electrode  121  and the second electrode  123  are both formed of a transparent conductive film, a double-sided emission light-emitting device may be formed. 
     The transparent conductive film may be made of, for example, indium tin oxide (ITO), indium zinc oxide (IZO) or indium gallium zinc oxide (IGZO). The metal with high reflectivity may be, for example, Ag. 
     In some embodiments, the light-emitting functional layer  122  includes a light-emitting layer  1221 . In some other embodiments, as shown in  FIG. 12 , the light-emitting functional layer  122  includes at least one of a hole injection layer (HIL)  1222 , a hole transport layer (HTL)  1223 , an electron transport layer (ETL)  1224  and an electron injection layer (EIL)  1225  in addition to the light-emitting layer  1221 . In a case where all of the above layers are included, the hole injection layer  1222 , the hole transport layer  1223 , the light-emitting layer  1221 , the electron transport layer  1224  and the electron injection layer  1225  are sequentially stacked on the first electrode  121  as the anode. 
     As shown in  FIGS. 3 and 4 , the display panel  1  further includes a pixel defining layer  131 . The pixel defining layer  131  includes a plurality of opening regions. The light-emitting layers  1221  of a light-emitting device  120  is disposed in an opening region, so that portions of the light-emitting layers  1221  corresponding to the light-emitting devices  120  are isolated from each other by the pixel defining layer  131 . In this case, when the light-emitting layer  1221  is formed on the planarization layer  115  by using the inkjet printing process, thicknesses of the light-emitting layers  1221  at some opening regions are non-uniform due to an error in the amount of ink between a plurality of nozzles, thereby leading to non-uniformity in brightness of light emitted from the light-emitting regions formed by the opening regions (a material for forming the light-emitting layers is sprayed in the opening regions, so that the opening regions become the light-emitting regions). 
     Therefore, in some embodiments of the present disclosure, another display substrate  11  is provided. As shown in  FIGS. 6A and 6B , in addition to the base substrate  110  and the plurality of light-emitting devices  120  disposed on the base substrate  110 , the display substrate  11  further includes a first pixel defining layer  130  disposed on the base substrate  110  and a second pixel defining layer  140  disposed on the base substrate  110 . 
     A material of the first pixel defining layer  130  and a material of the second pixel defining layer  140  are not limited in the embodiments of the present disclosure. In some embodiments, the material of the first pixel defining layer may or may not be the same as the material of the second pixel defining layer. In a case where the material of the first pixel defining layer  130  is the same as the material of the second pixel defining layer  140 , the first pixel defining layer  130  and the second pixel defining layer  140  may be fabricated simultaneously to simplify a fabrication process. 
     In some embodiments, as shown in  FIGS. 6A and 9 to 11 , the second pixel defining layer  140  is located on the first pixel defining layer  130 . In this way, a height d 1  of the second pixel defining layer and a height d 2  of the first pixel defining layer do not need to be too large, and a blocking portion with a sufficient height can be formed between two adjacent second opening regions  013 . The blocking portion is a portion where the first pixel defining layer  130  and the second pixel defining layer  140  are stacked, so a height of the blocking portion is a sum of d 1  and d 2  (d 1 +d 2 ). However, the solution is not limited thereto. In some embodiments, the second pixel defining layer  140  is not located on the first pixel defining layer  130 . 
     For example, as shown in  FIG. 6B , the second pixel defining layer  140  is directly disposed on the base substrate  110 . In this way, since there does not exist a structure in which the first pixel defining layer  130  and the second pixel defining layer  140  are stacked, side faces of a second opening region  013  are continuous and flat, and light emitted by the light-emitting layer  1221  will not be refracted or scattered. Moreover, when the ink is injected into the second opening region  013 , defects such as penetration will not occur at an interlayer interface between the first pixel defining layer  130  and the second pixel defining layer  140 , and defects such as wrinkles will not occur at the interlayer interface between the first pixel defining layer  130  and the second pixel defining layer  140  after the ink is cured. In this case, when the material of the first pixel defining layer  130  is the same as the material of the second pixel defining layer  140 , the first pixel defining layer  130  and the second pixel defining layer  140  may be fabricated simultaneously to simplify the fabrication process. 
     The first pixel defining layer  130  includes a plurality of first opening regions  011 , and each first opening region  011  exposes at least a portion of a first electrode  121 . 
     In some embodiments, each first opening region  011  may expose a portion or the whole of a first electrode  121 . As shown in  FIGS. 6A to 6B , a bottom surface of the first opening region  011  is smaller than a surface of the first electrode  121  away from the base substrate  110 , and thus one first opening region  011  exposes a portion of one first electrode  121 . As shown in  FIGS. 9 to 11 , the bottom surface of the first opening region  011  is as large as the surface of the first electrode  121  away from the base substrate  110 , and thus one first opening region  011  exposes the whole of one first electrode  121 . 
     In some embodiments, as shown in  FIGS. 6A and 6B , a shape of a cross section of the first electrode  121  is a long strip. 
     In some embodiments, as shown in  FIGS. 9, 10 and 11 , an orthographic projection of the surface of the first electrode  121  away from the base substrate  110  on the base substrate  110  is located within an orthographic projection of a surface of the first electrode  121  proximate to the base substrate  110  on the base substrate  110 , and the surface of the first electrode  121  proximate to the base substrate  110  is a surface formed by a surface A 1 , a surface A 3 , and a side face A 2  connecting and surrounding the surface A 1  and the surface A 3  shown in  FIG. 9 . That is, the shape of the cross section of the first electrode  121  is a regular trapezoid. 
     The second pixel defining layer  140  includes a plurality of second opening regions  013 , and each second opening region  013  corresponds to at least two first opening regions  011 . Orthogonal projections of the at least two first opening regions  011  on the base substrate  110  are located within an orthogonal projection of the second opening region  013  on the base substrate  110 . 
     In some embodiments, the at least two first opening regions  011  may include only two first opening regions  011 , or may include three or more first opening regions  011 . 
     Since a first opening region  011  exposes at least a portion of a first electrode  121 , a first opening region  011  corresponds to a first electrode  121 , and the number of first opening regions  011  is the same as the number of first electrodes  121 . On this basis, the number of first electrodes  121  exposed by the second opening region  013  may be two, three or more than three. 
     In some embodiments, the numbers of first electrodes  121  exposed by the second opening regions  013  may or may not be the same. For example, as shown in  FIG. 7 , a second opening region  013  exposes a column of first electrodes  121 . For another example, as shown in  FIG. 8 , a second opening region  013  exposes two or three first electrodes  121 . 
     The light-emitting layer  1221  is disposed in the second opening region  013  and overspreads the second opening region  013  in a plane perpendicular to a thickness direction of the base substrate  110 . 
     It will be easily understood that, a region defined by the first opening region  011  is also referred to as a light-emitting region  011 . A second opening region  013  corresponds to at least two first opening regions  011 , that is, a second opening region  013  includes at least two light-emitting regions. Since the light-emitting layer  1221  is disposed in the second opening region  013  and overspreads the second opening region  013  in the plane perpendicular to the thickness direction of the base substrate  110 , light emitted from all light-emitting regions  011  in the second opening region  013  has a same color. 
     The light-emitting layer  1221  overspreads the second opening region  013  in the plane perpendicular to the thickness direction of the base substrate  110 , that is, a surface of the light-emitting layer  1221  away from the base substrate  110  is farther away from the base substrate  110  than a surface of the first pixel defining layer  130  away from the base substrate  110 , which may make a thickness of the light-emitting layer  1221  in the second opening region more uniform, and improve uniformity of film formation. 
     In some embodiments, the second electrode  123  only covers the second opening region  013 . That is, a plurality of second electrodes  123  are separated from each other by the second pixel defining layer  140 . In some other embodiments, the second electrode  123  covers the second opening regions  013  and a surface of the second pixel defining layer  140  away from the base substrate  110 . 
     In the display substrate  11  provided by some embodiments of the present disclosure, the second pixel defining layer  140  is disposed on the first pixel defining layer  130 . That is, the surface of the first pixel defining layer  130  away from the base substrate  110  is closer to the base substrate  110  than the surface of the second pixel defining layer  140  away from the base substrate  110 . The second pixel defining layer  140  includes the plurality of second opening regions  013 , each second opening region  013  corresponds to the at least two first opening regions  011 , and the orthogonal projections of the at least two first opening regions  011  on the base substrate  110  are all located within the orthogonal projection of the second opening region  013  on the base substrate  110 . In a case where the light-emitting layer  1221  is disposed in the second opening region  013 , the light-emitting layer  1221  overspreads the second opening region  013  in the plane perpendicular to the thickness direction of the base substrate  110 . As a result, when the ink is injected into the second opening region  013  by using the inkjet printing, the ink can flow among at least two light-emitting regions  011  defined by the second opening region  013 , so that a difference of ink volume between light-emitting regions  011  in one second opening region  013  may be homogenized, thereby making thicknesses of the light-emitting layer  1221  formed in the light-emitting regions  011  in one second opening region  013  uniform. 
     In a case where the light-emitting devices  120  further include at least one of the hole injection layer  1222 , the hole transport layer  1223 , the electron transport layer  1224  and the electron injection layer  1225 , the layer(s) may each be located only in the second opening region  013 . That is, films disposed in a same layer may be separated by the second pixel defining layer  140 . Alternatively, the layer(s) may cover the second opening regions  013  and the surface of the second pixel defining layer  140  away from the base substrate  110 . That is, the layer(s) are whole layer(s). 
     In some embodiments, as shown in  FIG. 9 , the surface of the first electrode  121  away from the base substrate  110  is closer to the base substrate  110  than the surface of the first pixel defining layer  130  away from the base substrate  110 . In this way, the first pixel defining layer  130  may prevent light mixing between two adjacent light-emitting devices  120 . Although the light emitted by the light-emitting layer  1221  in the same second opening region  013  has a same color, considering that each light-emitting device  120  needs to emit light independently to improve a pixel resolution, light mixing between two adjacent light-emitting devices still needs to be avoided in each second opening region  013 . 
     However, the solution is not limited thereto. In some other embodiments, as shown in  FIG. 10 , the surface of the first electrode  121  away from the base substrate  110  is as close to the base substrate  110  as the surface of the first pixel defining layer  130  away from the base substrate  110 . That is, the surface of the first electrode  121  away from the base substrate  110  and the surface of the first pixel defining layer  130  away from the base substrate  110  are located in a same plane parallel to the base substrate  110 . In yet some other embodiments, as shown in  FIG. 11 , the surface of the first electrode  121  away from the base substrate  110  is farther away from the base substrate  110  than the surface of the first pixel defining layer  130  away from the base substrate  110 . In these two cases mentioned above, when the ink is injected into the second opening region  013 , the ink is entirely located on the interlayer interface between the first pixel defining layer  130  and the second pixel defining layer  140 , and thus defects such as penetration will not occur at the interlayer interface between the first pixel defining layer  130  and the second pixel defining layer  140 , and defects such as wrinkles will not occur at the interlayer interface between the first pixel defining layer  130  and the second pixel defining layer  140  after the ink is cured, and further the light emitted by the light-emitting layer  1221  will not be refracted or scattered at the wrinkles. 
     As shown in  FIG. 10 , in a case where the surface of the first pixel defining layer  130  away from the base substrate  110  and the surface of the first electrode  121  away from the base substrate  110  are located in the same plane, when the ink is injected into the second opening region  013  of the second pixel defining layer  140  to form the light-layer  1221 , a surface in contact with the ink is flat. Therefore, it is further ensured that the thicknesses of the light-emitting layer  1221  formed in all light-emitting regions  011  in the second opening region  013  are same, and brightness uniformity of light emitted from all light-emitting regions  011  is further improved. 
     In a case where the light-emitting layer  1221  is formed by using the inkjet printing process, the second pixel defining layer  140  is used to define the flowing of ink in the second opening region  013 , and thus the height of the second pixel defining layer  140  will be set relatively large. On this basis, in some embodiments, as shown in  FIG. 6A , a height d 1  of the second pixel defining layer  140  is greater than a height d 2  of the first pixel defining layer  130 . The height d 1  of the first pixel defining layer  130  and the height d 2  of the second pixel defining layer  140  each refer to a dimension in the thickness direction of the base substrate  110 . 
     In some embodiments, directions in which the first electrodes  121  exposed by the plurality of second opening regions  013  are respectively arranged are all the same. That is, directions in which the light-emitting regions  011  included in the plurality of second opening regions  013  are respectively arranged are the same. 
     For example, a plurality of first electrodes  121  exposed by each second opening region  013  are arranged in a column direction. Alternatively, a plurality of first electrodes  121  exposed by each second opening region  013  are arranged in a row direction. 
     In some embodiments, as shown in  FIG. 7 , an orthogonal projection of a second opening region  013  on the base substrate  110  covers orthogonal projections of a column of first opening regions  011  on the base substrate  110 . Alternatively, an orthogonal projection of a second opening region  013  on the base substrate  110  covers orthogonal projections of a row of first opening regions  011  on the base substrate  110 . 
     In some embodiments, as shown in  FIG. 8 , an orthogonal projection of a second opening region  013  on the base substrate  110  covers orthogonal projections of part of opening regions in a column of first opening regions  011  on the base substrate  110 . Alternatively, an orthogonal projection of a second opening region  013  on the base substrate  110  covers orthogonal projections of part of opening regions in a row of first opening regions  011  on the base substrate  110 . 
     In some embodiments of the present disclosure, since the directions in which the first electrodes  121  exposed by the plurality of second opening regions  013  are respectively arranged are all the same, it is convenient to fabricate the light-emitting layers  1221 . 
     In some embodiments, as shown in  FIGS. 9 to 11 , the display substrate  11  further includes a plurality of auxiliary patterns  150  disposed between the base substrate  110  and the plurality of first electrodes  121 , and a first electrode  121  is disposed on an auxiliary pattern  150 . 
     A material of the auxiliary patterns  150  is not limited. In a case where the light emitted by the light-emitting layer  1221  exits from the first electrodes  121 , the material of the auxiliary patterns  150  should be a transparent material. In a case where the light emitted by the light-emitting layer  1221  exits from the second electrode  123 , the material of the auxiliary patterns  150  may be a transparent material or a non-transparent material. 
     In some embodiments, the material of the auxiliary patterns  150  is the same as a material of the planarization layer  115 . On this basis, the auxiliary patterns  150  and the planarization layer  115  may be fabricated simultaneously or separately. In a case where the auxiliary patterns  150  and the planarization layer  115  are fabricated separately, as shown in  FIG. 13A , the planarization layer  115  is firstly formed on surfaces of the pixel circuits, and then the auxiliary patterns  150  are formed. In a case where the auxiliary patterns  150  and the planarization layer  115  are fabricated simultaneously, in some embodiments, as shown in  FIG. 13B , the planarization film  116  is formed on the surfaces of the pixel circuits, and then the planarization film  116  is etched to form convex portions and concave portions. In this case, the convex portions are the auxiliary patterns  150 . 
     Since the first electrode  121  is disposed on the auxiliary pattern  150 , a difference in height between the surface of the first electrode  121  away from the base substrate  110  and the surface of the first pixel defining layer  130  away from the base substrate  110  is reduced. In this way, when the ink is injected into the second opening region  013  of the second pixel defining layer  140  in a process of forming the light-emitting layer  1221  by using the inkjet printing process, the ink can flow more uniformly among the light-emitting regions  011  included in the second opening region  013 , thereby improving uniformity of thicknesses of the light-emitting layer  1221  formed in all light-emitting regions  011 , and further improving the brightness uniformity of the light emitted from the light-emitting regions  011 . In a case where the display substrate  11  is applied in an electroluminescent display apparatus, a quality of the electroluminescent display apparatus may be improved. 
     In some embodiments, an orthographic projection of a surface of the auxiliary pattern  150  away from the base substrate  110  on the base substrate  110  is located within an orthographic projection of a surface of the auxiliary pattern  150  proximate to the base substrate  110  on the base substrate  110 . Referring to  FIGS. 9, 10 and 11 , it can be seen that a shape of a cross section of the auxiliary pattern  150  is a regular trapezoid. On this basis, the first electrode  121  covers the surface of the auxiliary pattern  150  away from the base substrate  110  and side faces of the auxiliary pattern  150 . 
     Since the shape of the cross section of the auxiliary pattern  150  is the regular trapezoid, in a case where the first electrode  121  covers the auxiliary pattern  150 , the first electrode  121  can be prevented from being broken. Further, since the first electrode  121  is electrically connected to the drain  114  of the drive thin film transistor, the first electrode  121  can be prevented from being disconnected from the drain  114  of the drive thin film transistor. 
     As shown in  FIGS. 9, 10 and 11 , the first pixel defining layer  130  covers side faces of each first electrode  121 , and an orthographic projection of a surface of the first pixel defining layer  130  proximate to the base substrate  110  on the base substrate  110  is located within an orthographic projection of the surface of the first pixel defining layer  130  away from the base substrate  110  on the base substrate  110 . That is, a shape of a cross section of a portion of the first pixel defining layer  130  located between two adjacent first electrodes  121  is an inverted trapezoid. 
     Based on the above, it will be seen that two adjacent first electrodes  121  are separated by the first pixel defining layer  130 , and thus the first pixel defining layer  130  can insulate two adjacent first electrodes  121  from each other, which may avoid a short circuit. 
     As shown in  FIGS. 6A, 6B and 9 to 11 , an orthographic projection of the surface of the second pixel defining layer  140  away from the base substrate  110  on the base substrate  110  is located within an orthographic projection of a surface of the second pixel defining layer  140  proximate to the base substrate  110  on the base substrate  110 . That is, a shape of a cross section of a portion of the second pixel defining layer  140  located between two adjacent second opening regions  013  is a regular trapezoid. 
     In some embodiments of the present disclosure, the shape of the cross section of the portion of the second pixel defining layer  140  located between two adjacent second opening regions  013  is a regular trapezoid, thereby facilitating fabrication of the second pixel defining layer  140 . In addition, since the height of the second pixel defining layer  140  is relatively large, in a case where the light-emitting layer  1221  is formed in each second opening region  013 , it may be possible to prevent the ink for the inkjet printing from flowing into an adjacent second opening region  013 , and thus prevent color mixing of the light-emitting layers  1221  in two adjacent second opening regions  013 . 
     In some embodiments, the second opening regions  013  may be classified into first sub-opening regions, second sub-opening regions and third sub-opening regions. The light-emitting layers  1221  include red light-emitting layers for emitting red light located in the first sub-opening regions, green light-emitting layers for emitting green light located in the second sub-opening regions and blue light-emitting layers for emitting blue light located in the third sub-opening regions. 
     Shapes and arrangement manners of the first sub-opening region, the second sub-opening region and the third sub-opening region are not limited. For example, the first sub-opening region, the second sub-opening region and the third sub-opening region all extend in a first direction Y shown in  FIG. 8 , and the first sub-opening region, the second sub-opening region and the third sub-opening region are alternately arranged in a second direction X shown in  FIG. 8 . The first direction Y intersects with the second direction X. For example, the first direction Y is perpendicular to the second direction X. 
     Some embodiments of the present disclosure provide a method for manufacturing a display substrate, and the method may be used to manufacture the above display substrate. The method for manufacturing the display substrate, as shown in  FIG. 14 , includes following steps. 
     In S 100 , as shown in  FIG. 15 , a plurality of auxiliary patterns  150  are formed on a base substrate  110 . 
     A structure of the base substrate  110  is not limited, which may be referred to the above description, and will not be described in detail herein. 
     In S 101 , as shown in  FIG. 16 , a plurality of first electrodes  121  are formed on the auxiliary patterns  150 , and one first electrode  121  is disposed on one auxiliary pattern  150 . 
     In some embodiments, the first electrode  121  covers a surface of the auxiliary pattern  150  away from the base substrate  110 . In some other embodiments, the first electrode  121  covers a partial region of the surface of the auxiliary pattern  150  away from the base substrate  110 . 
     In some embodiments, the S 100  is not essential, and the plurality of first electrodes  121  may be formed on the base substrate  110 . 
     In S 102 , as shown in  FIG. 17 , a first pixel defining layer  130  is formed on the base substrate  110 . The first pixel defining layer  130  includes a plurality of first opening regions  011 , and each first opening region  011  exposes at least a portion of a first electrode  121 . 
     Herein, a first opening region  011  defines a light-emitting region, and a light-emitting region  011  corresponds to a first electrode  121 . 
     In S 103 , as shown in  FIG. 18 , a second pixel defining layer  140  is formed on the base substrate  110 . The second pixel defining layer  140  includes a plurality of second opening regions  013 , and a second opening region  013  corresponds to at least two first opening regions  011 . Orthogonal projections of the at least two first opening regions  011  on the base substrate  110  are located within an orthogonal projection of the second opening region  013  on the base substrate  110 . 
     Herein, a material of the first pixel defining layer  130  may or may not be the same as a material of the second pixel defining layer  140 . 
     Since a light-emitting region  011  corresponds to a first electrode  121 , the number of light-emitting regions  011  defined by the second opening region  013  is the same as the number of first electrodes  121  exposed by the second opening region  013 . 
     In a case where the light-emitting layer  1221  is formed by using the inkjet printing process, the second pixel defining layer  140  is used to define the flowing of ink in the second opening region  013 , and thus a height of the second pixel defining layer  140  will be set relatively large. On this basis, in some embodiments, the height of the second pixel defining layer  140  is greater than a height of the first pixel defining layer  130 . 
     As described above, in some embodiments, as shown in  FIGS. 6A and 18 , the second pixel defining layer  140  is located on the first pixel defining layer  130 , thereby forming a stacked structure. In some embodiments, as shown in  FIG. 6B , the first pixel defining layer  130  and the second pixel defining layer  140  may not form a stacked structure, and the second pixel defining layer  140  is directly formed on the base substrate  110 . That is, only the first pixel defining layer  130  is still formed at the position where only the first pixel defining layer  130  is formed shown in  FIG. 18 , and only the second pixel defining layer  140  is formed at the position where the first pixel defining layer  130  and the second pixel defining layer  140  are stacked shown in  FIG. 18 . 
     In S 104 , as shown in  FIG. 19 , light-emitting layers  1221  are formed in the second opening regions  013  by using the inkjet printing process. The light-emitting layers  1221  overspread the plurality of second opening regions  013  in a plane perpendicular to a thickness direction of the base substrate  110 . 
     It will be understood that, in a case where the light-emitting layer  1221  is formed by using the inkjet printing process, since the ink flows in the second opening region  013 , light emitted from all light-emitting regions  011  in the second opening region  013  has a same color. 
     In S 105 , as shown in  FIGS. 9 to 11 , a second electrode  123  is formed on the light-emitting layer  1221 . 
     In some embodiments, the second electrode  123  only covers the second opening region  013 . In some other embodiments, the second electrode  123  covers the second opening regions  013  and a surface of the second pixel defining layer  140  away from the base substrate  110 . 
     Herein, the second electrode  123  may be formed on the light-emitting layer  1221  by using a sputtering process or an evaporation process. 
     The method for manufacturing the display substrate provided by some embodiments of the present disclosure has the same beneficial effects as the display substrate  11  as described above, and the beneficial effects will not be described in detail herein. 
     In a case where the first electrode  121  is an anode and the second electrode  123  is a cathode, in some embodiments, after the S 103  and before the S 104 , the method for manufacturing the display substrate further includes: forming a hole injection layer  1222  and/or a hole transport layer  1223  at least in the second opening region  013 ; and/or, after the S 104  and before the S 105 , the method for manufacturing the display substrate further includes: forming an electron injection layer  1225  and/or an electron transport layer  1224  on the light-emitting layer  1221  and at least in the second opening region  013 . 
     In a case where the first electrode  121  is a cathode and the second electrode  123  is an anode, in some embodiments, after the S 103  and before the S 104 , the method for manufacturing the display substrate further includes: forming the electron injection layer  1225  and/or the electron transport layer  1224  at least in the second opening region  013 ; 
     and/or, after the S 104  and before the S 105 , the method of manufacturing the display substrate further includes: forming the hole injection layer  1222  and/or the hole transport layer  1223  on the light-emitting layer  1221  and at least in the second opening region  013 . 
     Based on the above, the hole injection layer  1222 , the hole transport layer  1223 , the electron injection layer  1225  and the electron transport layer  1224  may be formed by using the inkjet printing process. The hole injection layer  1222 , the hole transporting layer  1223 , the electron injection layer  1225  and the electron transporting layer  1224  may also be formed by using the evaporation process. 
     On this basis, the hole injection layer  1222 , the hole transport layer  1223 , the electron injection layer  1225  and the electron transport layer  1224  may be formed only in the second opening region  013 . The hole injection layer  1222 , the hole transporting layer  1223 , the electron injection layer  1225  and the electron transport layer  1224  may also be formed in the second opening regions  013  and the surface of the second pixel defining layer  140  away from the base substrate  110 . That is, the hole injection layer  1222  and the hole transport layer  1223  are each a whole layer, or the electron injection layer  1225  and the electron transport layer  1224  are each a whole layer. 
     In some embodiments, the S 104  includes: 
     forming a red light-emitting layer for emitting red light in a first sub-opening region, a green light-emitting layer for emitting green light in a second sub-opening region and a blue light-emitting layer for emitting blue light in a third sub-opening region by using inkjet printing processes. The second opening region  013  is classified into the first sub-opening region, the second sub-opening region or the third sub-opening region. 
     Herein, an order of forming the red light-emitting layer, the green light-emitting layer and the blue light-emitting layer is not limited. For example, the red light-emitting layer is first formed in the first sub-opening region by using an inkjet printing process, and the green light-emitting layer is then formed in the second sub-opening region by using another inkjet printing process, and the blue light-emitting layer is finally formed in the third sub-opening region by using yet another inkjet printing process. For another example, the green light-emitting layer is first formed in the second sub-opening region by using an inkjet printing process, and the blue light-emitting layer is then formed in the third sub-opening region by using another inkjet printing process, and the red light-emitting layer is finally formed in the first sub-opening region by using yet another inkjet printing process. 
     Shapes and arrangement manners of the first sub-opening region, the second sub-opening region and the third sub-opening region are not limited. For example, the first sub-opening region, the second sub-opening region and the third sub-opening region all extend in a first direction Y shown in  FIG. 8 , and the first sub-opening region, the second sub-opening region and the third sub-opening region are alternately arranged in a second direction X shown in  FIG. 8 . The first direction Y intersects with the second direction X. For example, the first direction Y is perpendicular to the second direction X. 
     The foregoing descriptions are merely specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Changes or replacements that any person skilled in the art could conceive of within the technical scope of the present disclosure shall be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.