Display substrate, display panel and display device

Abstract

The invention provides a display substrate, a display panel and a display device. The display substrate comprises: a substrate; the pixel limiting layer is arranged on the substrate, the pixel limiting layer is provided with a plurality of pixel openings, the pixel openings define a plurality of sub-pixels, the sub-pixels are arranged in an array mode in the first direction and the second direction, and the pixel limiting layer comprises pixel limiting parts located between every two adjacent pixel openings; the side, facing the pixel opening, of the pixel limiting part is provided with an undercut structure, the undercut structure comprises a side concave part and a protruding part, and the protruding part protrudes in the direction facing the pixel opening relative to the side concave part; the side concave part comprises a first bottom part close to the substrate base plate; a first top portion facing away from the substrate; and an intermediate portion between the first bottom portion and the first top portion, the intermediate portion retracting a first distance relative to the first top portion in a direction away from the pixel opening; the first top is provided with a first protruding part, the first protruding part has a first height in the third direction, and the first height is smaller than the first distance.

Description

Display substrate, display panel and display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular to a display substrate, a display panel and a display device. BACKGROUND

[0002] Silicon-based organic light-emitting diode (OLED) is a micro display developed in recent years. With mature silicon-based semiconductor process, high PPI (pixel density) and high refresh rate OLED display can be prepared, which is applied in the field of VR (Virtual Reality) and AR (Augmented Reality). The display panel in the related art includes a plurality of pixel units to achieve high PPI display effect. However, due to the precision limitation of the traditional fine metal mask (FMM), the pixel isolation process is required to achieve the isolation between adjacent pixel units.

[0003] How to achieve effective isolation between pixels while minimizing the impact of the isolation structure on the light-emitting device and ensuring the display effect and service life of the display substrate is one of the important research topics for researchers.

[0004] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those skilled in the art.

[0005] SUMMARY

[0006] In one aspect, a display substrate is provided, comprising: a substrate; a pixel defining layer disposed on the substrate, the pixel defining layer having a plurality of pixel openings, the plurality of pixel openings defining a plurality of sub-pixels, the plurality of sub-pixels being arranged in a first direction and a second direction,

[0007] The pixel defining layer includes a pixel defining portion between two adjacent pixel openings, the pixel defining portion having an undercut structure on a side facing the pixel opening,

[0008] The undercut structure includes a side recess portion and a protruding portion, the protruding portion protruding in a direction facing the pixel opening relative to the side recess portion;

[0009] The side recess portion includes: a first bottom portion close to the substrate; a first top portion away from the substrate; and an intermediate portion between the first bottom portion and the first top portion,

[0010] The intermediate portion is recessed by a first distance relative to the first top portion in a direction away from the pixel opening; and

[0011] The first top portion has a first protruding portion having a first height in a third direction, the first height being less than the first distance, the third direction being perpendicular to both the first direction and the second direction.

[0012] According to some exemplary embodiments, the protruding portion includes a first protruding portion and a second protruding portion, the first protruding portion being located between the side recessed portion and the second protruding portion;

[0013] The second protruding portion protrudes relative to the first protruding portion in a direction toward the pixel opening; and

[0014] In the third direction, a surface of the first protruding portion away from the substrate is farther away from the substrate relative to a surface of the second protruding portion away from the substrate.

[0015] According to some exemplary embodiments, the first protruding portion protrudes relative to the side recessed portion in a direction toward the pixel opening by a second distance, the second distance being greater than the first distance.

[0016] According to some exemplary embodiments, the second protruding portion protrudes relative to the first protruding portion in a direction toward the pixel opening by a third distance, the first distance being greater than the third distance.

[0017] According to some exemplary embodiments, the second distance is more than 5 times the third distance.

[0018] According to some exemplary embodiments, in the third direction, the second protruding portion has a second height, the second height being less than the first height.

[0019] According to some exemplary embodiments, the first top portion includes a first surface away from the substrate, the intermediate portion includes a first side surface toward the direction of the pixel opening,

[0020] The first surface includes: a first vertex being farthest from the substrate in a third direction; and a second vertex being closest to the pixel opening in the first direction or the second direction,

[0021] In the first direction or the second direction, the first vertex is closer to the first side surface of the intermediate portion relative to the second vertex.

[0022] According to some exemplary embodiments, the intermediate portion comprises a first side surface facing the direction of the pixel opening, the first side surface having a plurality of first slope angles; the first protruding portion comprises a second surface away from the substrate, the second surface having a plurality of second slope angles, at least one of the first slope angles being greater than at least one of the second slope angles.

[0023] According to some exemplary embodiments, the plurality of first slope angles gradually increase in a direction away from the pixel opening; and / or,

[0024] the plurality of second slope angles gradually increase in a direction away from the pixel opening.

[0025] According to some exemplary embodiments, the first protruding portion further comprises a main body portion and a second protruding portion, the main body portion being located at a side of the first protruding portion close to the side recess portion, and the second protruding portion being located at a side of the first protruding portion close to the pixel opening; and

[0026] In a third direction, a height of the main body portion is less than a height of the second protruding portion.

[0027] According to some exemplary embodiments, the pixel defining layer comprises: a first pixel defining sub-layer, a second pixel defining sub-layer and a third pixel defining sub-layer sequentially stacked from a side away from the substrate,

[0028] wherein at least part of the first bottom portion, the first protruding portion and the second protruding portion are located in the first pixel defining sub-layer;

[0029] the intermediate portion is located in the second pixel defining sub-layer; and

[0030] the first top portion is located in the third pixel defining sub-layer.

[0031] According to some exemplary embodiments, a surface of the first pixel defining sub-layer away from the substrate has a first roughness; a surface of the third pixel defining sub-layer away from the substrate has a second roughness, the first roughness being less than the second roughness.

[0032] According to some exemplary embodiments, the display substrate further comprises: a first electrode layer located at a side of the pixel defining layer close to the substrate; and a light emitting functional layer located at a side of the pixel defining layer away from the substrate,

[0033] wherein the light emitting functional layer comprises: a charge generation layer; and a first light emitting functional sub-layer located at a side of the charge generation layer close to the substrate,

[0034] The first light-emitting functional sub-layer includes a first portion located in the pixel opening region, the first portion is spaced from the surface of the substrate away from the first electrode layer by a first interval distance, the first protruding portion is spaced from the surface of the substrate away from the first electrode layer by a second interval distance, and the first interval distance is less than the second interval distance.

[0035] According to some exemplary embodiments, the light-emitting functional layer includes a plurality of stacked light-emitting functional sub-layers in sequence away from the substrate, at least part of the plurality of light-emitting functional sub-layers includes a plurality of third protruding portions located above the protruding portion, and the plurality of third protruding portions are at least partially overlapped with the protruding portion in the orthographic projection on the substrate.

[0036] In the direction away from the substrate, the curvature of the protrusion of the plurality of third protruding portions decreases in sequence.

[0037] According to some exemplary embodiments, the first portion is spaced from the surface of the substrate away from the first electrode layer by a third interval distance, and the ratio of the second roughness to the third interval distance is in the range of 0.013 to 0.032. According to some exemplary embodiments, the first portion is spaced from the surface of the substrate away from the first electrode layer by a third interval distance, the third interval distance is less than 1500 angstroms, and the second roughness is in the range of 1.2 nanometers to 2 nanometers.

[0038] According to some exemplary embodiments, the first portion is spaced from the surface of the substrate away from the first electrode layer by a third interval distance, the third interval distance is less than or equal to 1000 angstroms, and the second roughness is in the range of 1.2 nanometers to 1.6 nanometers.

[0039] According to some exemplary embodiments, the first portion is spaced from the surface of the substrate away from the first electrode layer by a third interval distance, the third interval distance is greater than or equal to 1000 angstroms and less than 1500 angstroms, and the second roughness is in the range of 1.6 nanometers to 2 nanometers.

[0040] According to some exemplary embodiments, the first portion is spaced from the surface of the substrate away from the first electrode layer by a third interval distance, the third interval distance is greater than or equal to 1500 angstroms, and the second roughness is in the range of 2 nanometers to 3.5 nanometers.

[0041] According to some example embodiments, the plurality of sub-pixels includes first color sub-pixels, second color sub-pixels, and third color sub-pixels, the first color sub-pixels are configured to emit light of a first wavelength, the second color sub-pixels are configured to emit light of a second wavelength, the third color sub-pixels are configured to emit light of a third wavelength, the first wavelength is greater than the second wavelength, and the second wavelength is greater than the third wavelength.

[0042] The display substrate further includes a microcavity adjustment layer located on a side of the first electrode layer close to the substrate substrate,

[0043] The microcavity adjustment layer includes a first microcavity adjustment layer for adjusting light emission of the first color sub-pixels, a second microcavity adjustment layer for adjusting light emission of the second color sub-pixels, and a third microcavity adjustment layer for adjusting light emission of the third color sub-pixels,

[0044] The height of the first microcavity adjustment layer in the third direction is less than the height of the third microcavity adjustment layer in the third direction; and

[0045] The height of the first microcavity adjustment layer in the third direction is greater than the height of the second microcavity adjustment layer in the third direction.

[0046] According to some example embodiments, the pixel defining layer includes a first pixel defining portion located between the pixel opening corresponding to the first color sub-pixel and the pixel opening corresponding to the second color sub-pixel, wherein the roughness of the first top portion in the first pixel defining portion away from the surface of the substrate substrate is in the range of 1.6 nanometers to 2 nanometers.

[0047] According to some example embodiments, the pixel defining layer further includes a second pixel defining portion located between the pixel opening corresponding to the second color sub-pixel and the pixel opening corresponding to the third color sub-pixel, wherein the roughness of the first top portion in the second pixel defining portion away from the surface of the substrate substrate is in the range of 1.2 nanometers to 1.6 nanometers.

[0048] According to some example embodiments, the pixel defining layer further includes a third pixel defining portion located between the pixel opening corresponding to the third color sub-pixel and the pixel opening corresponding to the first color sub-pixel, wherein the roughness of the first top portion in the third pixel defining portion away from the surface of the substrate substrate is in the range of 2 nanometers to 3.5 nanometers.

[0049] According to some exemplary embodiments, the display substrate further comprises a reflective layer located on a side of the microcavity adjustment layer close to the substrate substrate; the reflective layer comprises a plurality of arrayed reflective portions, and a plurality of the pixel openings are respectively located in a plurality of the reflective portions.

[0050] The display substrate further comprises a plurality of first isolation portions located in gaps between the plurality of reflective portions.

[0051] The pixel defining portion further comprises a second isolation portion protruding in a direction towards the substrate substrate relative to the undercut structure, and a projection of the second isolation portion on the substrate substrate is located in a projection of the first isolation portion on the substrate substrate.

[0052] According to some exemplary embodiments, the first electrode layer comprises a plurality of first electrodes, and a plurality of the pixel openings are respectively located in a plurality of the first electrodes.

[0053] A height of the second isolation portion in the third direction is greater than a height of the first electrode in the third direction.

[0054] According to some exemplary embodiments, the display substrate further comprises a plurality of vias penetrating the microcavity adjustment layer, and a plurality of conductive connecting columns filling the plurality of vias, and the first electrode and the reflective portion are electrically connected through the conductive connecting columns.

[0055] According to some exemplary embodiments, the protruding portion further comprises a third protruding portion protruding in a direction towards the substrate substrate relative to the first protruding portion, and a projection of the third protruding portion on the substrate substrate at least partially overlaps with a projection of the conductive connecting column on the substrate substrate.

[0056] According to some exemplary embodiments, the display substrate further comprises a third light-emitting layer located on a side of the charge generation layer away from the substrate substrate, and the third light-emitting layer is configured to emit light of a third wavelength.

[0057] The third light-emitting layer comprises a second portion, a third portion and a fourth portion, a projection of the second portion on the substrate substrate at least partially overlaps with a projection of the side recess on the substrate substrate, the third portion is located at an intersection region of the side recess and the first protruding portion, a projection of the fourth portion on the substrate substrate at least partially overlaps with a projection of the first protruding portion on the substrate substrate, the third portion is connected with the second portion and the fourth portion, and the third portion protrudes in a direction close to the side recess relative to both the second portion and the fourth portion.

[0058] According to some exemplary embodiments, the material of the first pixel defining sub-layer comprises silicon oxide; and / or

[0059] the material of the second pixel defining sub-layer comprises silicon nitride; and / or,

[0060] the material of the third pixel defining sub-layer comprises silicon oxide.

[0061] In another aspect of the present disclosure, a display substrate is provided, comprising: a substrate; a pixel defining layer disposed on the substrate, the pixel defining layer having a plurality of pixel openings, the plurality of pixel openings defining a plurality of sub-pixels, the plurality of sub-pixels being arranged in an array along a first direction and a second direction,

[0062] the pixel defining layer comprises a pixel defining portion between two adjacent pixel openings, the pixel defining portion having an undercut structure on a side facing the pixel openings,

[0063] wherein the undercut structure comprises a side recess and a protruding portion, the protruding portion protruding in a direction towards the pixel openings relative to the side recess, the protruding portion having a first roughness away from a surface of the substrate;

[0064] the side recess comprises: a first bottom portion proximate to the substrate; a first top portion away from the substrate; and an intermediate portion between the first bottom portion and the first top portion,

[0065] wherein the first bottom portion is in the same layer as the protruding portion; and

[0066] the first top portion has a second roughness away from the surface of the substrate, the first roughness being less than the second roughness.

[0067] In yet another aspect of the present disclosure, a display panel is provided, comprising the display substrate of any one of the above.

[0068] In still another aspect of the present disclosure, a display device is provided, comprising the display substrate of any one of the above or the display panel of the above. BRIEF DESCRIPTION OF DRAWINGS

[0069] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0070] FIG. 1 is a partial plan view of a display substrate according to an embodiment of the present disclosure;

[0071] FIG. 2 is a cross-sectional view of the display substrate of FIG. 1 taken along line AA’ according to an embodiment of the present disclosure;

[0072] FIG. 3 is a partially enlarged schematic view of the S1 region in FIG. 2;

[0073] FIG. 4 is a cross-sectional schematic view of an undercut structure according to an embodiment of the present disclosure;

[0074] FIG. 5 is an enlarged schematic view according to a first protrusion in FIG. 4;

[0075] FIG. 6 is a cross-sectional schematic view of an undercut structure according to an embodiment of the present disclosure;

[0076] FIG. 7 is a cross-sectional schematic view of an undercut structure according to an embodiment of the present disclosure;

[0077] FIG. 8 is a cross-sectional schematic view of partial film layers in a display substrate according to an embodiment of the present disclosure;

[0078] FIGS. 9A-9C are cross-sectional schematic views of partial film layers in a display substrate according to an embodiment of the present disclosure;

[0079] FIG. 10 is a cross-sectional schematic view of partial film layers in a display substrate according to an embodiment of the present disclosure;

[0080] FIG. 11 is a cross-sectional schematic view of a display substrate taken along line BB' in FIG. 1 according to an embodiment of the present disclosure;

[0081] FIG. 12 is a structural schematic view of a display panel according to some embodiments of the present disclosure; and

[0082] FIG. 13 is a structural schematic view of a display device according to some embodiments of the present disclosure.

[0083] It should be noted that, for the sake of clarity, the size of a layer, structure, or region in the drawings can be exaggerated or shrunk, i.e., the drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0084] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong within the scope of the present disclosure.

[0085] It is to be noted that the size and relative sizes of the elements in the drawings can be exaggerated for clarity and / or descriptive purposes. Therefore, the size and relative sizes of the elements in the drawings are not necessarily drawn to scale. In the description and drawings, like reference numerals designate like elements throughout the several views.

[0086] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the ordinary meaning as understood by a person of ordinary skill in the art. The terms "first", "second", and similar terms in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different constituent parts. The terms "comprise", "comprising", and similar terms are intended to mean that the elements or objects listed after the term are encompassed by the term, and are not intended to exclude other elements or objects.

[0087] In this document, unless otherwise specified, directional terms such as "upper", "lower", "left", "right", "inner", "outer", and the like are used to indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure, and do not indicate or imply that the devices, elements or components referred to must have a particular orientation, be constructed or operated in a particular orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms cannot be understood as a limitation on the present disclosure.

[0088] In this document, directional expressions "first direction", "second direction" are used to describe different directions of display substrate or display panel, for example, row direction and column direction of pixel unit. It should be understood that such representation is only an exemplary description, and is not a limitation on the present disclosure.

[0089] In this document, unless otherwise specified, the expression "electrically connected" can mean that two components or elements are directly electrically connected, for example, component or element A is in direct contact with component or element B, and an electrical signal can be transmitted therebetween; can also mean that two components or elements are electrically connected through a conductive medium such as a conductive wire, for example, component or element A is electrically connected to component or element B through a conductive wire to transmit an electrical signal between the two components or elements; can also mean that two components or elements are electrically connected through at least one electronic component, for example, component or element A is electrically connected to component or element B through at least one thin film transistor to transmit an electrical signal between the two components or elements.

[0090] In the present disclosure, "about" means not strictly limited to the boundary, allowing a range of values within the process and measurement error.

[0091] The technical terms involved in the present disclosure are briefly described below so that relevant personnel can better understand the present scheme.

[0092] Distortion: due to the large height difference at the partition structure, the film layer of the evaporation material in the OLED device may have a rapid change in film layer morphology at the partition structure, forming a distortion. It should be understood that the probability of leakage at the distortion is higher.

[0093] Some embodiments of the present disclosure provide a display substrate. The display substrate comprises: a substrate and a pixel defining layer disposed on the substrate. The pixel defining layer has a plurality of pixel openings, the plurality of pixel openings defining a plurality of sub-pixels, the plurality of sub-pixels being arranged in an array along a first direction and a second direction. The pixel defining layer comprises a pixel defining portion between two adjacent pixel openings, the pixel defining portion having an undercut structure on a side facing the pixel opening. The undercut structure comprises a side recess portion and a protruding portion, the protruding portion protruding in a direction facing the pixel opening relative to the side recess portion. The side recess portion comprises: a first bottom portion close to the substrate; a first top portion away from the substrate; and an intermediate portion between the first bottom portion and the first top portion. The intermediate portion is recessed by a first distance in a direction away from the pixel opening relative to the first top portion; and the first top portion has a first protruding portion, the first protruding portion having a first height in a third direction, the first height being smaller than the first distance, the third direction being perpendicular to both the first direction and the second direction.

[0094] By designing the pixel defining portion between the pixel openings to have a plurality of undercut structures, the overall height of the pixel defining portion can be reduced while ensuring effective partitioning between pixels, so that the morphology of the plurality of film layers above the pixel defining portion is gentle. By designing a protruding structure in the first top portion of the undercut structure, the stability of the first top portion can be improved, thereby improving the stability of the undercut structure, reducing the probability of film layer distortion at the undercut structure, reducing leakage, and improving the stability of the display substrate.

[0095] FIG. 1 is a partial plan view of a display substrate according to an embodiment of the present disclosure.

[0096] Exemplarily, in some embodiments of the present disclosure, referring to FIG. 1, the display substrate 100 comprises a substrate 1. The substrate 1 comprises a display area AA and a non-display area NA. The display substrate 100 comprises a plurality of sub-pixels SP in the display area AA, the plurality of sub-pixels SP being arranged in an array along a first direction X and a second direction Y.

[0097] Exemplarily, the display substrate 100 further comprises a plurality of first electrodes 20, for example, the first electrodes 20 can be anodes of light emitting devices in the sub-pixels SP. The plurality of first electrodes 20 are arranged in an array along the first direction X and the second direction Y. The display substrate 100 further comprises a pixel definition layer PDL located on a side of the first electrodes 20 away from the substrate 1, and the pixel definition layer PDL has a plurality of pixel openings VH. The plurality of pixel openings VH define light emitting areas of the plurality of sub-pixels SP. Exemplarily, a projection of the pixel definition layer PDL on the substrate 1 at least partially overlaps a projection of the plurality of first electrodes 20 on the substrate 1, so that the first electrodes 20 of adjacent sub-pixels SP are disconnected from each other. The projections of the plurality of pixel openings VH on the substrate 1 respectively fall within the projections of the plurality of first electrodes 20 on the substrate 1, and define the light emitting areas of the sub-pixels SP.

[0098] Exemplarily, the plurality of first electrodes 20 are in one-to-one correspondence with the plurality of sub-pixels SP, and the area of the first electrode 20 is greater than the light emitting area of the sub-pixel.

[0099] It should be noted that the embodiments of the present disclosure do not make special restrictions on the design of the pixel openings VH and the first electrodes 20. For example, although the pixel openings VH and the first electrodes 20 are shown as squares in the drawings, in other embodiments, the pixel openings and the first electrodes can also be various shapes such as rectangles, ellipses, circles, triangles, etc. In addition, the light emitting units of different colors corresponding to different pixel openings can adopt various arrangement manners known in the art, and the embodiments of the present disclosure do not make special restrictions.

[0100] FIG. 2 is a schematic cross-sectional view of the display substrate taken along the line AA' in FIG. 1 according to an embodiment of the present disclosure; and FIG. 3 is a partially enlarged schematic view of an S1 region in FIG. 2.

[0101] Exemplarily, in some embodiments of the present disclosure, in combination with reference to FIGS. 1 and 2, the display substrate 100 comprises a substrate 1 and a first electrode layer 2 disposed on the substrate 1. The first electrode layer 2 can comprise a plurality of first electrodes 20 arranged at intervals.

[0102] Exemplarily, the first electrode layer 2 can comprise a plurality of conductive layers stacked in sequence away from the substrate 1, for example, a first electrode first sub-layer 21, a first electrode second sub-layer 22, and a first electrode third sub-layer 23. For example, the material of the first electrode first sub-layer 21 can comprise molybdenum, the material of the first electrode second sub-layer 22 can comprise aluminum, and the material of the first electrode third sub-layer 23 can comprise molybdenum.

[0103] It should be noted that the embodiments of the present disclosure illustratively show that the first electrode layer includes three conductive layers, but the embodiments of the present disclosure are not limited thereto. In the embodiments of the present disclosure, the first electrode layer can also include a single conductive layer, two conductive layers, or more conductive layers.

[0104] Illustratively, the pixel definition layer PDL can include a pixel definition portion PDL1.

[0105] Continuing to refer to FIG. 2, the display substrate 100 can further include a light-emitting functional layer 3 located on the side of the pixel definition layer PDL away from the substrate substrate 1, a second electrode layer 4 located on the side of the light-emitting functional layer 3 away from the substrate substrate 1, and an encapsulation layer 5 located on the side of the second electrode layer 4 away from the substrate substrate 1. For example, the second electrode layer 4 can be a cathode of the light-emitting device.

[0106] In some embodiments, the encapsulation layer 5 can include a plurality of sub-encapsulation layers stacked in sequence away from the substrate substrate 1. For example, the encapsulation layer 5 can include a first sub-encapsulation layer 51, a second sub-encapsulation layer 52, and a third sub-encapsulation layer 53. For example, the material of the first sub-encapsulation layer 51 can include an inorganic material, the material of the second sub-encapsulation layer 52 can include an organic material, and the material of the third sub-encapsulation layer 53 can include an inorganic material. By alternately designing inorganic materials and organic materials, the ability of the encapsulation layer 5 to isolate water and oxygen can be improved, thereby improving the service life of the display substrate.

[0107] In some embodiments, the substrate substrate 1 can be a silicon substrate. The light-emitting device in the display substrate 100 can be an OLED light-emitting device. In order to improve the performance, brightness and service life of the light-emitting device, the OLED light-emitting device can adopt a stacked OLED device structure. The stacked OLED device structure includes two or more light-emitting layers, and the plurality of light-emitting layers are connected in series by a charge generation layer CGL, thereby improving the light-emitting efficiency of the light-emitting device. For example, in a silicon-based OLED device, a yellow light-emitting layer and a blue light-emitting layer can be connected in series, or a red-green light-emitting layer and a blue light-emitting layer can be connected in series, thereby forming white light. Further combined with a light filtering structure, such as a filter, to form three-color light, thereby realizing color display.

[0108] Illustratively, in combination with reference to FIGS. 2 and 3, the light-emitting functional layer 3 can include a plurality of stacked light-emitting functional sub-layers 31 away from the substrate substrate 1 in sequence. For example, the plurality of stacked light-emitting functional sub-layers 31 can include a second light-emitting functional sub-layer GL02 located on the side of the pixel definition layer PDL away from the substrate substrate. For example, the second light-emitting functional sub-layer GL02 can include one or more film layers of a hole injection layer, a hole transport layer, and an electron blocking layer.

[0109] Exemplarily, the plurality of layer-stacked light-emitting functional sub-layers 31 can further include a first light-emitting layer EML1 located on a side of the second light-emitting functional sub-layer GL02 away from the substrate substrate 1. For example, the first light-emitting layer EML1 can be configured to emit light of a first wavelength, for example, the light of the first wavelength is red light.

[0110] Exemplarily, the plurality of layer-stacked light-emitting functional sub-layers 31 can further include a second light-emitting layer EML2 located on a side of the first light-emitting layer EML1 away from the substrate substrate 1. For example, the second light-emitting layer EML2 can be configured to emit light of a second wavelength, for example, the light of the second wavelength is green light.

[0111] Exemplarily, the plurality of layer-stacked light-emitting functional sub-layers 31 can further include: a first light-emitting functional sub-layer GL01 located on a side of the second light-emitting layer EML2 away from the substrate substrate 1; and a charge generation layer CGL located on a side of the first light-emitting functional sub-layer GL01 away from the substrate substrate 1. Exemplarily, the first light-emitting functional sub-layer GL01 can be an electron transport layer. In some embodiments, the first light-emitting functional sub-layer GL01 and the charge generation layer CGL can be two film layers arranged adjacently.

[0112] Exemplarily, the charge generation layer CGL can include a first sub-charge generation layer CGL1 and a second sub-charge generation layer CGL2. For example, the first sub-charge generation layer CGL1 can be an N-type charge generation layer, and the second sub-charge generation layer CGL2 can be a P-type charge generation layer. In some embodiments, the second sub-charge generation layer CGL2 can also function as a buffer layer for adjusting the recombination efficiency of carriers or adjusting the transmission rate of carriers.

[0113] Exemplarily, the plurality of layer-stacked light-emitting functional sub-layers 31 can further include: a third light-emitting functional sub-layer GL03 located on a side of the charge generation layer CGL away from the substrate substrate 1. For example, the third light-emitting functional sub-layer GL03 can be an exciton blocking layer. The exciton blocking layer can improve the recombination probability of electron-hole pairs in the light-emitting layer, thereby improving the light-emitting efficiency of the light-emitting device.

[0114] Exemplarily, the plurality of layer-stacked light-emitting functional sub-layers 31 can further include: a third light-emitting layer EML3 located on a side of the third light-emitting functional sub-layer GL03 away from the substrate substrate 1. For example, the third light-emitting layer EML3 can be configured to emit light of a third wavelength, for example, the light of the third wavelength is blue light.

[0115] Exemplarily, the plurality of stacked light-emitting functional sub-layers 31 can further include a fourth light-emitting functional sub-layer GL04 located on the side of the third light-emitting layer EML3 away from the substrate substrate 1, and a fifth light-emitting functional sub-layer GL05 located on the side of the fourth light-emitting functional sub-layer GL04 away from the substrate substrate 1. In some embodiments, the fourth light-emitting functional sub-layer GL04 can simultaneously function as an electron transport layer and a hole blocking layer. The fifth light-emitting functional sub-layer GL05 can be an electron injection layer.

[0116] It should be noted that although the embodiments of the present disclosure exemplarily show that the light-emitting functional layer 3 in the stacked OLED device includes the second light-emitting functional sub-layer GL02, the first light-emitting layer EML1, the second light-emitting layer EML2, the first light-emitting functional sub-layer GL01, the charge generation layer CGL, the third light-emitting functional sub-layer GL03, the third light-emitting layer EML3, the fourth light-emitting functional sub-layer GL04, and the fifth light-emitting functional sub-layer GL05. However, the embodiments of the present disclosure are not limited thereto, and the light-emitting functional layer of the present disclosure can be designed according to actual needs, and some film layers can be reduced or some film layers can be added.

[0117] In the stacked OLED device, due to the high conductivity of the charge generation layer CGL, when the charge generation layer between adjacent pixels is not blocked, it is easy to cause horizontal crosstalk between the pixels.

[0118] According to some exemplary embodiments of the present disclosure, by designing the undercut structure UDC at both ends of the pixel defining part PDL1, the charge generation layer CGL between adjacent pixels can be disconnected at the undercut structure UDC, thereby reducing the horizontal crosstalk between the pixels and improving the display effect of the display substrate. For example, in combination with FIGS. 2 and 3, the pixel defining layer PDL can include a pixel defining part PDL1 located between two adjacent pixel openings VH. The pixel defining part PDL1 has an undercut structure UDC on the side facing the pixel opening VH. In some embodiments, the pixel defining part PDL1 has an undercut structure on the side facing the plurality of pixel openings VH. For example, the pixel defining part PDL1 has an undercut structure UDC on the side facing the pixel opening VH1 (such as the side pointed by X1 in FIG. 2), and the pixel defining part PDL1 also has an undercut structure UDC on the side facing the pixel opening VH2 (such as the side pointed by X2 in FIG. 2). The second charge generation part CGL12 located above the undercut structure UDC and the first charge generation part CGL11 located in the pixel opening VH region are disconnected at the undercut structure UDC, thereby avoiding horizontal crosstalk between adjacent pixels.

[0119] By designing a plurality of undercut structures on the plurality of sides of the pixel defining part PDL1, the blocking effect of the pixel defining part PDL1 can be further improved, which is conducive to reducing the probability of electric leakage of the display substrate and improving the display effect of the display substrate.

[0120] However, the inventors have found through research that, due to the large step difference at the undercut structure and the complex film layer morphology, the film layer in the region near the undercut structure is prone to collapse, which may cause the undercut structure to fail or the charge generation layer CGL to be short-circuited. In order to improve the stability of the undercut structure, further optimization design of the undercut structure is needed to improve the stability of the film layer in the region near the undercut structure and reduce the probability of distortion of the film layer, thereby improving the reliability and display effect of the display substrate.

[0121] FIG. 4 is a schematic cross-sectional view of an undercut structure according to an embodiment of the present disclosure.

[0122] For example, in some embodiments of the present disclosure, referring to FIG. 4, the undercut structure UDC includes a side recess UDC1 and a protruding portion UDC2. The protruding portion UDC2 protrudes in a direction toward the pixel opening VH relative to the side recess UDC1, for example, the direction indicated by X2 in FIG. 4 is the direction toward the pixel opening VH.

[0123] By designing the protruding portion UDC2 to protrude in a direction toward the pixel opening VH relative to the side recess UDC1, the light-emitting area of part of the light-emitting layer in the stacked OLED device can be adjusted. For example, referring to FIGS. 3 and 4 in combination, due to the electrical insulation of the protruding portion UDC2, the first light-emitting layer EML1 and the second light-emitting layer EML2 in the region above the protruding portion UDC2 do not emit light. The third light-emitting layer EML3 can use the charge generation layer CGL as an anode, and thus the third light-emitting layer EML3 in the region above the protruding portion UDC2 can emit light. That is, the protruding portion UDC2 can adjust the relative light-emitting areas of the first light-emitting layer EML1, the second light-emitting layer EML2, and the third light-emitting layer EML3. For example, the light-emitting area of the third light-emitting layer EML3 is made larger than the light-emitting area of the first light-emitting layer EML1 or the second light-emitting layer EML2. The light-emitting area of the first light-emitting layer EML1 can be equal to the light-emitting area of the second light-emitting layer EML2.

[0124] In some embodiments, the first light-emitting layer EML1 can emit red light, the second light-emitting layer EML2 can emit green light, and the third light-emitting layer EML3 can emit blue light. Through the design of the protruding portion UDC2, the light-emitting area of the blue light can be made larger than the light-emitting area of the red light or the green light, which is beneficial to improve the relative light-emitting intensity of the blue light in the mixed light, thereby improving the problem of yellow color of the light of the stacked OLED light-emitting device.

[0125] Exemplarily, continuing to refer to FIG. 4, the undercut UDC1 includes: a first bottom UDC11 close to the substrate substrate; a first top UDC13 away from the substrate substrate; and an intermediate portion UDC12 between the first bottom UDC11 and the first top UDC13. The intermediate portion UDC12 is recessed by a first distance d1 relative to the first top UDC13 in a direction away from the pixel opening VH. For example, the direction away from the pixel opening in FIG. 4 can be a direction opposite to the X2 direction. It should be noted that the “first distance d1” in the embodiments of the present disclosure is the maximum undercut depth of the intermediate portion UDC12 relative to the first top UDC13.

[0126] In some embodiments, the first distance d1 is in a range of 0.05 microns to 0.06 microns.

[0127] By designing the undercut structure on both sides of the pixel defining portion as a structure in which the middle is recessed and the two ends protrude, the height of the pixel defining layer required to effectively isolate the charge generation layer is low, so that the film layer above the pixel defining layer can be made more gentle at the edge of the undercut structure, for example, the cathode layer can be made more gentle, thereby improving the uniformity of the electric field distribution in the pixel and reducing edge stray light.

[0128] Exemplarily, the first top UDC13 includes a first protruding portion UDC131 and a first flat portion UDC132. The first protruding portion UDC131 protrudes relative to the first flat portion UDC132 in a direction away from the substrate substrate.

[0129] Exemplarily, the first protruding portion UDC131 has a first height h1 in a third direction Z, and the first height h1 is less than the first distance d1. The third direction Z is perpendicular to both the first direction X and the second direction Y. Alternatively, the third direction Z can be the light output direction of the display substrate. It should be noted that the first height h1 refers to the maximum height of the first protruding portion UDC131 in the third direction Z.

[0130] Due to the overhanging arrangement of at least part of the first top UDC13, by designing a protruding portion on the side of the first top UDC13 away from the substrate substrate, the stability of the first top UDC13 can be improved, thereby improving the stability of the undercut structure UDC. By optimizing the first height h1 of the first protruding portion to be less than the undercut depth (i.e., the first distance d1) of the intermediate portion UDC12, the stability of the undercut structure UDC can be further improved.

[0131] Exemplarily, continuing to refer to FIG. 4, the first top portion UDC13 includes a first surface UDC130 distanced from the substrate substrate 1, and the middle portion UDC12 includes a first side surface UDC121 facing the direction of the pixel opening VH. The first surface UDC130 includes a first vertex O1 farthest from the substrate substrate 1 in the third direction Z, for example, the first vertex O1 can be the highest point in the first convex portion UDC131. The first surface UDC130 also includes a second vertex O2 closest to the pixel opening VH in the first direction X or the second direction Y. Exemplarily, in the first direction X or the second direction Y, the first vertex O1 is closer to the first side surface UDC121 of the middle portion UDC12 than the second vertex O2. That is, the first vertex O1 is located in the middle region of the first surface UDC130. In the direction facing the pixel opening VH, the interval distance between at least a portion of the first surface UDC130 in the first top portion UDC13 (for example, the upper surface of the first convex portion UDC131) and the substrate substrate 1 first increases and then decreases. Through such a design, the other film layers located above the first convex portion UDC131 can be smoothly transitioned, which can reduce the probability of distortion of the film layers, thereby facilitating improvement of the display effect of the display substrate.

[0132] Exemplarily, continuing to refer to FIG. 4, the protruding portion UDC2 includes a first protruding portion UDC21 and a second protruding portion UDC22. The first protruding portion UDC21 is located between the side recess portion UDC1 and the second protruding portion UDC22. The second protruding portion UDC22 protrudes in the direction facing the pixel opening VH relative to the first protruding portion UDC21. In the third direction Z, the surface UDC211 of the first protruding portion UDC21 distanced from the substrate substrate is farther away from the substrate substrate relative to the surface UDC221 of the second protruding portion UDC22 distanced from the substrate substrate. That is, the overall height of the first protruding portion UDC21 is greater than the overall height of the second protruding portion UDC22.

[0133] Exemplarily, the first protruding portion UDC21 protrudes in the direction facing the pixel opening VH relative to the side recess portion UDC1 by a second distance d2, and the second distance d2 is greater than the first distance d1.

[0134] Exemplarily, the second protruding portion UDC22 protrudes in the direction facing the pixel opening VH relative to the first protruding portion UDC21 by a third distance d3, and the first distance d1 is greater than the third distance d3.

[0135] By such a design, at least two steps can be formed on the side of the protrusion UDC2 close to the pixel opening VH, so that the film layer above the protrusion UDC2 is more smoothly transitioned in this area, for example, at least one or more of the first light-emitting layer EML1, the second light-emitting layer EML2 and the third light-emitting layer EML3 can be smoothly transitioned in the area where the protrusion UDC2 is located, which is beneficial to improve the light-emitting uniformity of the edge of the light-emitting layer, thereby facilitating to improve the display effect of the display substrate.

[0136] In some embodiments, the sum of the second distance d2 and the third distance d3 is in the range of 0.1 microns to 0.15 microns.

[0137] Exemplarily, the second distance d2 is more than 5 times of the third distance d3.

[0138] Exemplarily, in the third direction Z, the second protrusion UDC22 has a second height h2. That is, the surface of the second protrusion UDC22 away from the substrate h2 is spaced from the surface of the second protrusion close to the substrate UDC222 by the second height h2. Exemplarily, the second height h2 is less than the first height h1. It should be noted that the second height h2 refers to the maximum height of the second protrusion UDC22 in the third direction Z.

[0139] By such a design, the area where the film layer above the protrusion UDC2 is smoothly transitioned can be closer to the light-emitting area, which is beneficial to improve the light-emitting uniformity of the edge of the light-emitting layer, thereby facilitating to improve the display effect of the display substrate.

[0140] FIG. 5 is an enlarged schematic view of the first protrusion in FIG. 4.

[0141] Exemplarily, in combination with reference to FIGS. 4 and 5, the first protrusion UDC21 further includes a main body UDC212 and a second protrusion UDC213. The main body UDC212 is located on the side of the first protrusion UDC21 close to the side recess UDC1, and the second protrusion UDC213 is located on the side of the first protrusion UDC21 close to the pixel opening VH. In the third direction Z, the height h3 of the main body is less than the height h4 of the second protrusion. It should be noted that the height h3 of the main body here refers to the maximum height of the main body UDC212 in the third direction Z, and the height h4 of the second protrusion refers to the maximum height of the second protrusion UDC213 in the third direction Z.

[0142] A small protrusion, for example, the second protrusion UDC213, is designed on one side of the first protrusion UDC21 close to the second protrusion UDC22, which can make the film layer change more gently above the intersection area of the first protrusion UDC21 and the second protrusion UDC22, thereby improving the uniformity of the edge light emission of the light-emitting layer, and being beneficial to improve the display uniformity of the display substrate.

[0143] FIG. 6 is a schematic cross-sectional view of an undercut structure according to an embodiment of the present disclosure.

[0144] Exemplarily, in some embodiments of the present disclosure, in combination with reference to FIG. 3 and FIG. 6, the intermediate portion UDC12 includes a first side surface UDC121 facing the direction of the pixel opening VH, and the first side surface UDC121 has a plurality of first slope angles a1. The first protrusion UDC21 includes a second surface UDC211 away from the substrate, and the second surface UDC211 has a plurality of second slope angles a2. At least one first slope angle a1 is greater than at least one second slope angle a2.

[0145] It should be noted that the surface (for example, the first side surface UDC121 and the second surface UDC211) here is composed of a plurality of points, and each point can have a corresponding slope angle, so that the surface has a plurality of slope angles. Among them, the "slope angle" of a point on the surface refers to the included angle between the tangent of the point on the surface and the horizontal direction, and the horizontal direction is parallel to the first direction X.

[0146] Exemplarily, the plurality of first slope angles a1 gradually increase in the direction away from the pixel opening VH.

[0147] Exemplarily, the plurality of second slope angles a2 gradually increase in the direction away from the pixel opening VH.

[0148] Through such design, the surface of the protrusion UDC2 and the side recess UDC1 can be gently lowered in the direction towards the pixel opening VH. On the one hand, the stability of the undercut structure UDC can be improved, and on the other hand, the other film layers above the undercut structure UDC can be more gently transitioned in the area where the undercut structure is located, thereby improving the uniformity of the film layer of the light-emitting functional layer or the second electrode layer in the area, reducing the edge stray light, reducing the leakage, and improving the display uniformity of the display substrate.

[0149] FIG. 7 is a schematic cross-sectional view of an undercut structure according to an embodiment of the present disclosure.

[0150] Exemplarily, in the embodiments of the present disclosure, referring to FIG. 7, the pixel defining layer PDL includes: a first pixel defining sub-layer PDL01, a second pixel defining sub-layer PDL02 and a third pixel defining sub-layer PDL03 which are sequentially stacked along the side away from the substrate base. Among them, at least part of the first bottom UDC11, the first protruding part UDC21 and the second protruding part UDC22 are located in the first pixel defining sub-layer PDL01. The middle part UDC12 is located in the second pixel defining sub-layer PDL02. The first top UDC13 is located in the third pixel defining sub-layer PDL03.

[0151] The materials of the plurality of pixel defining sub-layers can be the same or different. For example, the material of the first pixel defining sub-layer PDL01 can include silicon oxide. And / or, the material of the second pixel defining sub-layer PDL02 can include silicon nitride; and / or, the material of the third pixel defining sub-layer PDL03 includes silicon oxide. The plurality of pixel defining sub-layers can have different etching rates under the same etching process condition. For example, the etching rate of the second pixel defining sub-layer can be higher than that of the third pixel defining sub-layer, so that the recessed structure of the middle part UDC12 recessed relative to the first top UDC13 in the direction away from the pixel opening can be formed in the etching process. The pixel defining part with the undercut structure can effectively isolate the charge generating layer, reduce the lateral crosstalk between pixels, reduce the leakage rate, and improve the display effect of the display substrate.

[0152] Exemplarily, the surface PDL011 of the first pixel defining sub-layer PDL01 away from the substrate base has a first roughness. The surface PDL031 of the third pixel defining sub-layer PDL03 away from the substrate base has a second roughness. The first roughness is smaller than the second roughness. In some embodiments, the first top UDC13 is located in the third pixel defining sub-layer PDL03, that is, the upper surface of the first top UDC13 and the surface PDL031 of the third pixel defining sub-layer PDL03 away from the substrate base can be the same surface.

[0153] Exemplarily, the second roughness is in the range of 1.2 nanometers to 3.5 nanometers.

[0154] The roughness of the upper surface of the first top UDC 13 in the undercut structure can be increased to increase the adhesion between the first top UDC 13 and the upper film layer. For example, referring to FIGS. 2, 3, and 7, increasing the roughness of the upper surface of the first top UDC 13 can increase the adhesion between the first top UDC 13 and the light-emitting functional layer 3, thereby reducing the probability of collapse of the upper light-emitting functional layer 3 at the undercut structure UDC, reducing the probability of distortion of the upper film layer at the undercut structure UDC, and improving the uniformity of the display substrate and reducing the edge stray light. On the other hand, the increased adhesion between the upper film layer and the first top UDC 13 can also reduce the probability of collapse of the charge generation layer CGL at the undercut structure UDC, avoid shorting of the charge generation layer CGL at the undercut structure UDC, and reduce the probability of leakage of the display substrate.

[0155] FIG. 8 is a schematic cross-sectional view of part of the film layers in a display substrate according to an embodiment of the present disclosure.

[0156] For example, referring to FIGS. 2 and 8, in an embodiment of the present disclosure, the display substrate can include a first electrode layer 2 located on the side of the pixel definition layer PDL close to the substrate substrate, and a light-emitting functional layer 3 located on the side of the pixel definition layer PDL away from the substrate substrate.

[0157] For example, the light-emitting functional layer 3 can include a charge generation layer CGL and a first light-emitting functional sublayer GL01 located on the side of the charge generation layer CGL close to the substrate substrate. For example, the first light-emitting functional sublayer can include at least one film layer of a first electron transport layer, a first hole blocking layer, etc. For example, the light-emitting functional layer 3 can further include one or more film layers between the first electrode layer 2 and the first light-emitting functional sublayer GL01. For example, the light-emitting functional layer 3 can further include one or more film layers of a hole injection layer, a hole transport layer, an exciton blocking layer, a first light-emitting layer, a second light-emitting layer, etc.

[0158] For example, the first light-emitting functional sublayer GL01 includes a first part GL011 located in the pixel opening VH region. The surface of the first part GL011 away from the substrate substrate is spaced apart from the surface of the first electrode layer 2 away from the substrate substrate by a first spacing distance h5. The surface of the first protruding part UDC131 in the undercut structure UDC away from the substrate substrate is spaced apart from the surface of the first electrode layer 2 away from the substrate substrate by a second spacing distance h6, and the first spacing distance h5 is less than the second spacing distance h6.

[0159] It should be noted that the first interval distance h5 in the embodiments of the present disclosure refers to the maximum interval distance from the surface of the substrate away from the first electrode layer 2. In the embodiments of the present disclosure, the second interval distance h6 refers to the maximum interval distance from the surface of the substrate away from the first electrode layer 2 in the first protruding part UDC131 of the undercut structure UDC.

[0160] Through such a design, a step difference can be formed between the second charge generating part CGL12 located above the undercut structure UDC and the first charge generating part CGL11 located in the pixel opening VH region, so that the second charge generating part CGL12 located above the undercut structure UDC and the first charge generating part CGL11 located in the pixel opening VH region are more likely to be disconnected at the undercut structure, avoiding the short circuit of the charge generating layer between adjacent pixels, which is beneficial to improve the display effect of the display substrate.

[0161] In some embodiments, one or more film layers need to be designed between the first light-emitting functional sub-layer GL01 and the first electrode 2, for example, one or more of the hole injection layer, the hole transport layer, the exciton blocking layer, the first light-emitting layer, the second light-emitting layer, and the like. With the increase of the type of film layer or the increase of the thickness of a single film layer, the interval distance between the first light-emitting functional sub-layer GL01 and the first electrode 2 will increase, resulting in a decrease in the step difference between the second charge generating part CGL12 located above the undercut structure UDC and the first charge generating part CGL11 located in the pixel opening VH region. In the case of a decrease in the step difference, if the film layer located above the undercut structure UDC collapses, it is more likely to cause a short circuit between the second charge generating part CGL12 located above the undercut structure UDC and the first charge generating part CGL11 located in the pixel opening VH region, which adversely affects the display substrate.

[0162] In order to reduce the probability of short circuit of the charge generating layer CGL, the embodiments of the present disclosure optimize the roughness of the upper surface of the first top layer UDC13 in the undercut structure UDC. The greater the roughness of the upper surface of the first top layer UDC13, the better the adhesion between the film layer above the undercut structure UDC and the first top layer UDC13, which can reduce the probability of collapse of the film layer above the undercut structure UDC. However, the increase of the roughness of the upper surface of the first top layer UDC13 has an adverse effect on the film layer consistency of the film layer above the undercut structure UDC. Therefore, the roughness of the upper surface of the first top layer UDC13 needs to be designed in consideration of the adhesion of the undercut structure UDC and the film layer above the undercut structure UDC, and the influence of the roughness of the upper surface of the first top layer UDC13 in the undercut structure UDC on the film layer consistency of the film layer above the undercut structure UDC.

[0163] FIGS. 9A-9C are schematic cross-sectional views of partial film layers in a display substrate according to embodiments of the present disclosure.

[0164] To balance the blocking effect of the undercut structure UDC on the charge generation layer and the uniformity of the film layer above the undercut structure, the roughness of the first top portion UDC13 of the undercut structure UDC away from the surface UDC130 of the substrate substrate can be designed and optimized for different device structures. The first top portion UDC13 is located in the third pixel definition sub-layer PDL03, and the surface of the third pixel definition sub-layer PDL03 away from the substrate substrate has a second roughness, that is, the surface UDC130 of the first top portion UDC13 away from the substrate substrate has a second roughness.

[0165] For example, in embodiments of the present disclosure, in combination with reference to FIGS. 9A-9C, the first portion GL011 of the first light-emitting functional sub-layer GL01 located in the pixel opening VH region is spaced apart from the surface of the first electrode layer 2 away from the substrate substrate by a third spacing distance h7. The third spacing distance h7 can have different values in different stacked OLED devices. For example, the third spacing distance h7 in the embodiment shown in FIG. 9A is smaller than the third spacing distance h7 in the embodiment shown in FIG. 9B. For another example, the third spacing distance h7 in the embodiment shown in FIG. 9B is smaller than the third spacing distance h7 in the embodiment shown in FIG. 9C.

[0166] For example, in the embodiment shown in FIG. 9A, the third spacing distance h7 is small, for example, the third spacing distance h7 is less than or equal to 1000 angstroms. At this time, the step between the second charge generation portion CGL12 located above the undercut structure UDC and the first charge generation portion CGL11 located in the pixel opening VH region is large. Accordingly, the second roughness of the surface UDC130 of the first top portion UDC13 away from the substrate substrate can be small, for example, the second roughness is in the range of 1.2 nanometers to 1.6 nanometers.

[0167] In some embodiments, the third spacing distance h7 can be about 500 angstroms, and the second roughness of the surface UDC130 of the first top portion UDC13 away from the substrate substrate is in the range of 1.2 nanometers to 1.6 nanometers.

[0168] Through such a design, the blocking effect of the undercut structure UDC on the charge generation layer CGL can be improved while the influence of the first top portion UDC13 on the film layer uniformity of the film layer above can be minimized.

[0169] Exemplarily, in the embodiment shown in FIG. 9B, the third interval distance h7 is small, for example, the third interval distance h7 is greater than or equal to 1000 angstroms and less than 1500 angstroms. At this time, the step difference between the second charge generation part CGL12 located above the undercut structure UDC and the first charge generation part CGL11 located in the pixel opening VH region is reduced compared to the step difference of the embodiment shown in FIG. 9A. Accordingly, the second roughness of the first top part UDC13 away from the surface UDC130 of the substrate substrate is increased compared to the second roughness in the embodiment of FIG. 9A, for example, the second roughness is in the range of 1.6 nanometers to 2 nanometers, so that the adhesion between the film layer above the undercut structure UDC and the undercut structure UDC can be increased, and the isolation effect of the undercut structure UDC is ensured.

[0170] In some embodiments, the third interval distance h7 can be about 1000 angstroms, and the second roughness of the first top part UDC13 away from the surface UDC130 of the substrate substrate is in the range of 1.6 nanometers to 2 nanometers.

[0171] Exemplarily, the third interval distance h7 is less than 1500 angstroms, and the second roughness is in the range of 1.2 nanometers to 2 nanometers.

[0172] Exemplarily, in the embodiment shown in FIG. 9C, the third interval distance h7 is large, for example, the third interval distance h7 is greater than or equal to 1500 angstroms. At this time, the step difference between the second charge generation part CGL12 located above the undercut structure UDC and the first charge generation part CGL11 located in the pixel opening VH region is smaller than the step difference of the embodiment shown in FIG. 9B. Accordingly, the second roughness of the first top part UDC13 away from the surface UDC130 of the substrate substrate is further increased compared to the second roughness in the embodiment of FIG. 9B. For example, the second roughness is in the range of 2 nanometers to 3.5 nanometers. Through such a design, the adhesion between the film layer above the undercut structure UDC and the first top part UDC13 can be further improved, the film layer above the undercut structure UDC is prevented from collapsing, and the isolation effect of the undercut structure UDC on the charge generation layer CGL is ensured.

[0173] In some embodiments, the third interval distance h7 can be about 1500 angstroms, and the second roughness of the first top part UDC13 away from the surface UDC130 of the substrate substrate is in the range of 2 nanometers to 3.5 nanometers.

[0174] In some embodiments, within a certain range, as the third interval distance h7 increases, the second roughness increases accordingly. Through such a design, the adhesion between the film layer above the undercut structure UDC and the first top part UDC13 can be improved in the case of reducing the step difference, the film layer above the undercut structure UDC is prevented from collapsing, and the isolation effect of the undercut structure UDC on the charge generation layer CGL is ensured.

[0175] Exemplarily, the ratio of the second roughness to the third interval distance h7 is in the range of 0.013 to 0.032.

[0176] In some embodiments, the second roughness of the first top UDC13 away from the surface UDC130 of the substrate substrate can be controlled by adjusting the etching power, gas ratio, and the like. For different device structures, the roughness of the first top UDC13 away from the surface UDC130 of the substrate substrate of the undercut structure UDC is optimized and designed, which can improve the distortion of the undercut structure UDC region, reduce the leakage current, increase the efficiency of the light-emitting device, and improve the service life and reliability of the display substrate.

[0177] FIG. 10 is a schematic cross-sectional view of part of the film layers in a display substrate according to an embodiment of the present disclosure.

[0178] Exemplarily, in the embodiments of the present disclosure, referring to FIG. 10, after the pixel defining layer PDL is formed, subsequent preparation of multiple film layers is also required, for example, preparation of the light-emitting functional layer, the second electrode layer, and the like. In the stacked OLED device, the multiple film layers can be formed by an evaporation process. Due to the shielding effect of the first top portion in the undercut structure UDC, the film layer material in the subsequent preparation process cannot fill part of the region in the side recess UDC1, for example, part of the S2 region in FIG. 10, resulting in the appearance of a partial blank area (i.e., an area that does not contain any material in the OLED light-emitting device) in the side recess UDC1. The film layer near the blank area is more prone to distortion. In some embodiments, as part of the film layer in the light-emitting functional layer accumulates, the step difference at the intersection of the side recess UDC1 and the first protrusion UDC21 gradually decreases, so that part of the film layer in the light-emitting functional layer can form a continuous film layer structure at the undercut structure UDC.

[0179] Exemplarily, the light-emitting functional layer 3 can include a plurality of stacked light-emitting functional sub-layers 31 sequentially away from the substrate substrate 1. Due to the existence of multiple steps between the side recesses UDC1, the protrusions UDC2 and the first electrode layer 2, at least part of the plurality of light-emitting functional sub-layers 31 can include a plurality of third protrusions 310 located above the protrusions UDC2. The orthographic projection of the plurality of third protrusions 310 on the substrate substrate at least partially overlaps with the orthographic projection of the protrusions UDC2 on the substrate substrate. Wherein, in the direction away from the substrate substrate (for example, the third direction Z), the curvature of the protrusions of the plurality of third protrusions 310 sequentially decreases. For example, the plurality of third protrusions 310 can include a third protrusion first sub-portion 311, a third protrusion second sub-portion 312 and a third protrusion third sub-portion 313 sequentially away from the substrate substrate. Exemplarily, the curvature of the surface 3110 of the third protrusion first sub-portion 311 away from the substrate substrate is greater than the curvature of the surface 3120 of the third protrusion second sub-portion 312 away from the substrate substrate. The curvature of the surface 3120 of the third protrusion second sub-portion 312 away from the substrate substrate is greater than the curvature of the surface 3130 of the third protrusion third sub-portion 313 away from the substrate substrate.

[0180] Through such a design, the transition of the film layer above the protrusions UDC2 can be made more gentle, the influence of the steps on the consistency of the film layer can be reduced, the edge stray light can be reduced, and the display effect of the display substrate can be improved.

[0181] It should be noted that in some embodiments, the plurality of third protrusions 310 can further include a third protrusion fourth sub-portion, a third protrusion fifth sub-portion and the like. The specific number of the plurality of third protrusions 310 can be different according to the number of film layers in the device structure. The embodiments of the present disclosure do not limit the specific number of the plurality of third protrusions 310.

[0182] Exemplarily, continuing to refer to FIG. 10, the light-emitting functional layer can include a third light-emitting layer EML3 located on the side of the charge generation layer CGL away from the substrate substrate, and the third light-emitting layer EML3 is configured to emit light of a third wavelength, for example, the light of the third wavelength is blue light. The third light-emitting layer EML3 can include a second part EML32, a third part EML33, and a fourth part EML34. The second part EML32 has a projection on the substrate substrate that at least partially overlaps with a projection of the side undercut UDC1 on the substrate substrate. The third part EML33 is located at the intersection area of the side undercut UDC1 and the first protrusion UDC21. That is, the projection of the third part EML33 on the substrate substrate at least partially overlaps with the projection of the side undercut UDC1 on the substrate substrate; and the projection of the third part EML33 on the substrate substrate at least partially overlaps with the projection of the first protrusion UDC21 on the substrate substrate. The fourth part EML34 has a projection on the substrate substrate that at least partially overlaps with the projection of the first protrusion UDC21 on the substrate substrate.

[0183] Exemplarily, the third part EML33 is connected to both the second part EML32 and the fourth part EML34. And the third part EML33 protrudes in the direction close to the side undercut UDC1 relative to both the second part EML32 and the fourth part EML34.

[0184] Through such a design, the multiple film layers located on the side of the third light-emitting layer EML3 away from the substrate substrate can be continuously and gently transitioned at the undercut structure UDC. For example, the cathode layer can be made more gentle, so that the uniformity of the electric field distribution in the pixel can be improved, and the edge stray light can be reduced. FIG. 11 is a schematic cross-sectional view of a display substrate taken along line BB' in FIG. 1 according to an embodiment of the present disclosure.

[0185] In some embodiments, the display substrate can further include a microcavity adjustment layer for adjusting the light-emitting intensity of different color subpixels, so that the display effect of the display substrate is better.

[0186] Exemplarily, referring to FIG. 11, the multiple subpixels SP can include a first color subpixel sp1, a second color subpixel sp2, and a third color subpixel sp3. The first color subpixel sp1 is configured to emit light of a first wavelength, the second color subpixel sp2 is configured to emit light of a second wavelength, and the third color subpixel sp3 is configured to emit light of a third wavelength. The first wavelength is greater than the second wavelength, and the second wavelength is greater than the third wavelength. For example, the light of the first wavelength is red light, the light of the second wavelength is green light, and the light of the third wavelength is blue light.

[0187] The display substrate can further include a microcavity adjustment layer 6 located on the side of the first electrode layer 2 close to the substrate. The microcavity adjustment layer 6 includes a first microcavity adjustment layer 61 for adjusting the light emission of the first color sub-pixel sp1, a second microcavity adjustment layer 62 for adjusting the light emission of the second color sub-pixel sp2, and a third microcavity adjustment layer 63 for adjusting the light emission of the third color sub-pixel sp3.

[0188] Exemplarily, the height h11 of the first microcavity adjustment layer 61 in the third direction Z is less than the height h13 of the third microcavity adjustment layer 63 in the third direction Z.

[0189] Exemplarily, the height h11 of the first microcavity adjustment layer 61 in the third direction Z is greater than the height h12 of the second microcavity adjustment layer 62 in the third direction Z.

[0190] Through such a design, the light emission intensity of sub-pixels of different colors can be adjusted, the light emission intensity of the sub-pixels can be improved, color deviation can be reduced, and the display effect of the display substrate can be improved.

[0191] In some embodiments, due to the different heights of the microcavity adjustment layer 6 in different sub-pixels, the step difference between different sub-pixels is different. Correspondingly, the roughness of the upper surface of the first top UDC13 in the pixel defining part PDL is also different. Exemplarily, the pixel defining layer can include a second pixel defining part PDL12 located between the pixel opening corresponding to the second color sub-pixel sp2 and the pixel opening corresponding to the third color sub-pixel sp3. The second pixel defining part PDL12 has an undercut structure UDC on the side facing the pixel opening of the second color sub-pixel sp2. The second pixel defining part PDL12 also has an undercut structure UDC on the side facing the pixel opening of the third color sub-pixel sp2.

[0192] Due to the large difference in the thickness of the microcavity adjustment layer of the second color sub-pixel sp2 and the third color sub-pixel sp3, the second pixel defining part PDL12 can use a low-roughness design. For example, the roughness of the surface of the first top UDC13-2 in the second pixel defining part PDL12 away from the substrate is in the range of 1.2 nanometers to 1.6 nanometers.

[0193] Exemplarily, the pixel defining layer can further include a third pixel defining part PDL13 located between the pixel opening corresponding to the third color sub-pixel sp3 and the pixel opening corresponding to the first color sub-pixel sp1. The third pixel defining part PDL13 has an undercut structure UDC on the side facing the pixel opening of the third color sub-pixel sp3. The third pixel defining part PDL13 also has an undercut structure UDC on the side facing the pixel opening of the first color sub-pixel sp1.

[0194] Since the thickness of the microcavity adjustment layer of the first color sub-pixel sp1 and the third color sub-pixel sp3 is small, the third pixel defining part PDL13 can use a high-roughness design. For example, the roughness of the surface of the first top UDC13-3 in the third pixel defining part PDL13 away from the substrate is in the range of 2 nanometers to 3.5 nanometers.

[0195] Exemplarily, the pixel defining layer can further include a first pixel defining part PDL11 located between the pixel opening corresponding to the first color sub-pixel sp1 and the pixel opening corresponding to the second color sub-pixel sp2. The first pixel defining part PDL11 has an undercut structure UDC on the side facing the pixel opening of the first color sub-pixel sp1. The first pixel defining part PDL11 also has an undercut structure UDC on the side facing the pixel opening of the second color sub-pixel sp2. The roughness of the surface of the first top UDC13-1 in the first pixel defining part PDL11 away from the substrate is in the range of 1.6 nanometers to 2 nanometers.

[0196] Through such a design, a low-roughness design can be used for the pixel defining part located in the area with a large step difference, ensuring the blocking effect of the pixel defining part while minimizing the impact of the pixel defining part on the film layer consistency of the upper film layer, which is beneficial to improving the display uniformity. A high-roughness design can be used for the pixel defining part located in the area with a small step difference, which can greatly improve the adhesion of the pixel defining part and the upper film layer, improve the stability of the film layer at the undercut structure, avoid the collapse of the film layer at the undercut structure, and is beneficial to ensuring the blocking effect of the pixel defining part and reducing the lateral crosstalk between pixels.

[0197] Exemplarily, the display substrate further includes a reflective layer 7 located on the side of the microcavity adjustment layer 6 close to the substrate. The reflective layer 7 includes a plurality of arrayed reflective parts 71. The orthographic projections of the plurality of pixel openings VH on the substrate fall within the orthographic projections of the plurality of reflective parts 71 on the substrate.

[0198] Exemplarily, the display substrate further includes a plurality of first isolation parts 8 located in the gaps between the plurality of reflective parts 71.

[0199] Exemplarily, the pixel defining part PDL can further include a second isolation part PDL20. The second isolation part PDL20 protrudes in the direction toward the substrate relative to the undercut structure UDC. The orthographic projection of the second isolation part PDL20 on the substrate falls within the orthographic projection of the first isolation part 8 on the substrate.

[0200] Exemplarily, the height h15 of the second isolation part PDL20 in the third direction Z is greater than the height h14 of the first electrode 20 in the third direction Z.

[0201] Through the design, the first electrodes of adjacent sub-pixels can be disconnected, the crosstalk or leakage between adjacent sub-pixels can be reduced, and the reliability of the display substrate can be improved.

[0202] Exemplarily, the display substrate further includes a plurality of vias VN penetrating the micro-cavity adjusting layer 6, and a conductive connecting column 9 filling the plurality of vias VN. The first electrode 20 and the reflecting part 71 can be electrically connected through the conductive connecting column 9. Exemplarily, an external driving circuit can be electrically connected with the first electrode 20 or the reflecting part 71, so as to realize signal transmission. Through the design, the wiring connection between the external driving circuit and the light-emitting device can be facilitated.

[0203] In some embodiments, since a deeper via VN needs to be formed, the film layer in the region above the via VN can be concave and uneven, which is not conducive to the consistency of the film layer in the subsequent process.

[0204] In some embodiments of the present disclosure, the protruding part UDC2 further includes a third protruding part UDC23. The third protruding part UDC23 protrudes in a direction towards the substrate in relation to the first protruding part UDC21. The orthographic projection of the third protruding part UDC23 on the substrate at least partially overlaps with the orthographic projection of the conductive connecting column 9 on the substrate. Through the design, a part of the film layer in the pixel defining layer can be used to fill the concave part near the conductive connecting column 9, which is conducive to improving the film layer consistency of the subsequent film layer.

[0205] Exemplarily, in some embodiments of the present disclosure, a display substrate 100 is provided. In combination with reference to FIGS. 1-3 and 7, the display substrate 100 includes a substrate 1 and a pixel defining layer PDL disposed on the substrate 1. The pixel defining layer PDL has a plurality of pixel openings VH, the plurality of pixel openings VH defining a plurality of sub-pixels SP, and the plurality of sub-pixels SP are arranged in a first direction X and a second direction Y.

[0206] The pixel defining layer PDL includes a pixel defining part PDL1 between two adjacent pixel openings VH, and the pixel defining part PDL1 has an undercut structure UDC on a side facing the pixel opening VH.

[0207] The undercut structure UDC includes a side recess UDC1 and a protruding part UDC2, and the protruding part UDC2 protrudes in a direction towards the pixel opening VH in relation to the side recess UDC1. The protruding part UDC2 has a first roughness away from the surface of the substrate. For example, the protruding part UDC2 is located in a first pixel defining sub-layer PDL01, and the first pixel defining sub-layer PDL01 has a first roughness away from the surface PDL011 of the substrate.

[0208] The undercut portion UDC1 includes a first bottom UDC11 close to the substrate substrate, a first top UDC13 away from the substrate substrate, and an intermediate portion UDC12 between the first bottom UDC11 and the first top UDC13.

[0209] Exemplarily, the first bottom UDC11 is located in the same layer as the protruding portion UDC2. For example, the first bottom UDC11 and the protruding portion UDC2 can be located in the first pixel defining sub-layer PDL01.

[0210] The first top UDC13 has a second roughness away from the surface of the substrate substrate. For example, the first top UDC13 is located in the third pixel defining sub-layer PDL03, and the third pixel defining sub-layer PDL03 has the second roughness away from the surface PDL031 of the substrate substrate. Exemplarily, the first roughness is smaller than the second roughness.

[0211] Through such a design, the adhesion of the undercut structure UDC and the upper film layer can be improved, the probability of collapse of the upper film layer at the undercut structure can be reduced, the distortion at the undercut structure can be improved, the current leakage can be reduced, the light emitting efficiency of the light emitting device can be improved, and the service life and reliability of the display substrate can be improved.

[0212] FIG. 12 is a structural schematic diagram of a display panel according to some embodiments of the present disclosure.

[0213] Optionally, embodiments of the present disclosure provide a display panel. Referring to FIG. 12, the display panel 200 can include the display substrate 100 described above.

[0214] FIG. 13 is a structural schematic diagram of a display device according to some embodiments of the present disclosure.

[0215] Optionally, embodiments of the present disclosure also provide a display device 300. Referring to FIG. 13, the display device 300 can include the display substrate 100 described above or the display panel 200 described above. The display device can include, but is not limited to, electronic paper, mobile phones, tablet computers, displays, notebook computers, digital photo frames, navigation devices, and any product or component having a display function. It should be understood that the display device has the same beneficial effects as the display substrate provided by the foregoing embodiments.

[0216] Although some embodiments of the general concept of the present disclosure have been shown and described, those of ordinary skill in the art will understand that changes can be made in these embodiments without departing from the principles and spirit of the general concept of the present disclosure, and the scope of the present disclosure is defined by the claims and their equivalents.

Claims

1. A display substrate, characterized by, The application includes: a substrate; a pixel defining layer disposed on the substrate, the pixel defining layer having a plurality of pixel openings, the plurality of pixel openings defining a plurality of sub-pixels, the plurality of sub-pixels being arranged in an array along a first direction and a second direction, the pixel defining layer includes a pixel defining portion between two adjacent pixel openings, the pixel defining portion has an undercut structure on a side facing the pixel opening, wherein the undercut structure includes a side recess and a protrusion, the protrusion protrudes in a direction towards the pixel opening relative to the side recess; the side recess includes a first bottom portion close to the substrate, a first top portion away from the substrate, and an intermediate portion between the first bottom portion and the first top portion, wherein the intermediate portion is recessed by a first distance in a direction away from the pixel opening relative to the first top portion; and the first top portion has a first protruding portion, the first protruding portion has a first height in a third direction, the first height is less than the first distance, the third direction is perpendicular to both the first direction and the second direction. 2.The display substrate of claim 1, wherein, the protrusion includes a first protrusion and a second protrusion, the first protrusion is between the side recess and the second protrusion; the second protrusion protrudes in a direction towards the pixel opening relative to the first protrusion; and in the third direction, a surface of the first protrusion away from the substrate is farther away from the substrate relative to a surface of the second protrusion away from the substrate. 3.The display substrate of claim 2, wherein, the first protrusion protrudes in a direction towards the pixel opening relative to the side recess by a second distance, the second distance is greater than the first distance. 4.The display substrate of claim 3, wherein, the second protrusion protrudes in a direction towards the pixel opening relative to the first protrusion by a third distance, the first distance is greater than the third distance. 5.The display substrate of claim 4, wherein, the second distance is more than 5 times the third distance. 6.The display substrate of any one of claims 2-5, wherein, in the third direction, the second protrusion has a second height, the second height is less than the first height. 7.The display substrate of any one of claims 1-6, wherein, the first top portion includes a first surface away from the substrate, the intermediate portion includes a first side surface towards the direction of the pixel opening, the first surface includes a first vertex farthest from the substrate in the third direction, and a second vertex closest to the pixel opening in the first direction or the second direction, wherein in the first direction or the second direction, the first vertex is closer to the first side surface of the intermediate portion relative to the second vertex. 8.The display substrate of any one of claims 2-6, wherein, the intermediate portion includes a first side surface towards the direction of the pixel opening, the first side surface has a plurality of first slope angles; the first protrusion includes a second surface away from the substrate, the second surface has a plurality of second slope angles, at least one of the first slope angles is greater than at least one of the second slope angles. 9.The display substrate of claim 8, wherein, the plurality of first slope angles gradually increase in a direction away from the pixel opening; and / or, the plurality of second slope angles gradually increase in a direction away from the pixel opening. 10.The display substrate of any one of claims 2-9, wherein, The first protruding portion further comprises a main body portion and a second protruding portion, the main body portion is located at one side of the first protruding portion close to the side recess portion, and the second protruding portion is located at one side of the first protruding portion close to the pixel opening; And In the third direction, the height of the main body portion is less than the height of the second protruding portion. 11.The display substrate of any one of claims 2-10, wherein, The pixel defining layer comprises a first pixel defining sub-layer, a second pixel defining sub-layer and a third pixel defining sub-layer which are sequentially stacked along a side away from the substrate base plate, Wherein, at least part of the first bottom portion, the first protruding portion and the second protruding portion are located in the first pixel defining sub-layer; The intermediate portion is located in the second pixel defining sub-layer; and The first top portion is located in the third pixel defining sub-layer. The surface of the first pixel defining sub-layer away from the substrate base plate has a first roughness; the surface of the third pixel defining sub-layer away from the substrate base plate has a second roughness, and the first roughness is less than the second roughness. 12.The display substrate of claim 11, wherein, The display substrate further comprises a first electrode layer located at one side of the pixel defining layer close to the substrate base plate, and a light emitting functional layer located at one side of the pixel defining layer away from the substrate base plate, 13. The display substrate according to any one of claims 2-12, wherein, Wherein, the light emitting functional layer comprises a charge generation layer and a first light emitting functional sub-layer located at one side of the charge generation layer close to the substrate base plate, Wherein, the first light emitting functional sub-layer comprises a first portion located in the pixel opening area, the surface of the first portion away from the substrate base plate is spaced apart from the surface of the first electrode layer away from the substrate base plate by a first interval distance, the surface of the first protruding portion away from the substrate base plate is spaced apart from the surface of the first electrode layer away from the substrate base plate by a second interval distance, and the first interval distance is less than the second interval distance. The light emitting functional layer comprises a plurality of light emitting functional sub-layers which are sequentially stacked away from the substrate base plate, at least part of the plurality of light emitting functional sub-layers comprises a plurality of third protruding portions located above the protruding portion, and the orthographic projection of the plurality of third protruding portions on the substrate base plate at least partially overlaps the orthographic projection of the protruding portion on the substrate base plate; 14.The display substrate of claim 13, wherein, And In the direction away from the substrate base plate, the curvature of the protrusions of the plurality of third protruding portions decreases in sequence. The surface of the first portion close to the substrate base plate is spaced apart from the surface of the first electrode layer away from the substrate base plate by a third interval distance, and the ratio of the second roughness to the third interval distance is in the range of 0.013 to 0.

032. 15.The display substrate of claim 13, wherein, The surface of the first portion close to the substrate base plate is spaced apart from the surface of the first electrode layer away from the substrate base plate by a third interval distance, the third interval distance is less than 1500 angstroms, and the second roughness is in the range of 1.2 nanometers to 2 nanometers. 16.The display substrate of claim 13, wherein, The surface of the first portion close to the substrate base plate is spaced apart from the surface of the first electrode layer away from the substrate base plate by a third interval distance, the third interval distance is less than or equal to 1000 angstroms, and the second roughness is in the range of 1.2 nanometers to 1.6 nanometers. 17.The display substrate of claim 13, wherein, ​ 18.The display substrate of claim 13, wherein, The first portion is spaced from the surface of the substrate away from the surface of the substrate by a third spacing distance, the third spacing distance being greater than or equal to 1000 angstroms and less than 1500 angstroms, and the second roughness being in a range from 1.6 nm to 2 nm.

19. The display substrate of claim 13, wherein, The first portion is spaced from the surface of the substrate away from the surface of the substrate by a third spacing distance, the third spacing distance being greater than or equal to 1500 angstroms, and the second roughness being in a range from 2 nm to 3.5 nm.

20. The display substrate of claim 13, wherein, The plurality of sub-pixels includes a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel, the first color sub-pixel is configured to emit light of a first wavelength, the second color sub-pixel is configured to emit light of a second wavelength, and the third color sub-pixel is configured to emit light of a third wavelength, the first wavelength is greater than the second wavelength, and the second wavelength is greater than the third wavelength; The display substrate further includes a micro-cavity adjustment layer located on a side of the first electrode layer close to the substrate, The micro-cavity adjustment layer includes a first micro-cavity adjustment layer for adjusting light emission of the first color sub-pixel, a second micro-cavity adjustment layer for adjusting light emission of the second color sub-pixel, and a third micro-cavity adjustment layer for adjusting light emission of the third color sub-pixel, The height of the first micro-cavity adjustment layer in the third direction is less than the height of the third micro-cavity adjustment layer in the third direction; and The height of the first micro-cavity adjustment layer in the third direction is greater than the height of the second micro-cavity adjustment layer in the third direction. 21.The display substrate of claim 20, wherein, The pixel defining layer includes a first pixel defining portion located between the pixel opening corresponding to the first color sub-pixel and the pixel opening corresponding to the second color sub-pixel, and a roughness of the first top portion away from the surface of the substrate in the first pixel defining portion is in a range from 1.6 nm to 2 nm.

22. The display substrate of claim 20 or 21, wherein, The pixel defining layer further includes a second pixel defining portion located between the pixel opening corresponding to the second color sub-pixel and the pixel opening corresponding to the third color sub-pixel, and a roughness of the first top portion away from the surface of the substrate in the second pixel defining portion is in a range from 1.2 nm to 1.6 nm.

23. The display substrate of any of claims 20-22, wherein, The pixel defining layer further includes a third pixel defining portion located between the pixel opening corresponding to the third color sub-pixel and the pixel opening corresponding to the first color sub-pixel, and a roughness of the first top portion away from the surface of the substrate in the third pixel defining portion is in a range from 2 nm to 3.5 nm.

24. The display substrate of claim 20, wherein, The display substrate further includes a reflective layer located on a side of the micro-cavity adjustment layer close to the substrate, and the reflective layer includes a plurality of arrayed reflective portions, and the orthographic projections of the plurality of pixel openings on the substrate fall into the orthographic projections of the plurality of reflective portions on the substrate. The display substrate further includes a plurality of first isolation portions located in gaps between the plurality of reflective portions. The pixel defining part further comprises a second isolation part, the second isolation part protrudes in a direction towards the substrate in relation to the undercut structure, a projection of the second isolation part on the substrate falls within a projection of the first isolation part on the substrate. 25.The display substrate of claim 24, wherein, The first electrode layer comprises a plurality of first electrodes, a projection of the plurality of pixel openings on the substrate falls within a projection of the plurality of first electrodes on the substrate respectively; And A height of the second isolation part in the third direction is greater than a height of the first electrode in the third direction. 26.The display substrate of claim 25, wherein, The display substrate further comprises a plurality of vias penetrating the microcavity adjusting layer; and a conductive connecting column filling the plurality of vias, the first electrode and the reflection part are electrically connected through the conductive connecting column.

27. The display substrate of claim 26, wherein, The protruding part further comprises a third protruding part, the third protruding part protrudes in a direction towards the substrate in relation to the first protruding part, a projection of the third protruding part on the substrate at least partially overlaps with a projection of the conductive connecting column on the substrate. 28.The display substrate of claim 13, wherein, The display substrate further comprises a third light emitting layer located on a side of the charge generating layer away from the substrate, the third light emitting layer is configured to emit light of a third wavelength; And The third light emitting layer comprises a second part, a third part and a fourth part, a projection of the second part on the substrate at least partially overlaps with a projection of the side recess on the substrate; the third part is located at an intersection region of the side recess and the first protruding part; a projection of the fourth part on the substrate at least partially overlaps with a projection of the first protruding part on the substrate, the third part is connected with the second part and the fourth part; and the third part protrudes in a direction close to the side recess in relation to both the second part and the fourth part. 29.The display substrate of claim 11, wherein, The material of the first pixel defining sub-layer comprises silicon oxide; and / or The material of the second pixel defining sub-layer comprises silicon nitride; and / or The material of the third pixel defining sub-layer comprises silicon oxide.

30. A display substrate, characterized in that, Comprise: A substrate; A pixel defining layer disposed on the substrate, the pixel defining layer has a plurality of pixel openings, the plurality of pixel openings define a plurality of sub-pixels, the plurality of sub-pixels are arranged in an array along a first direction and a second direction, The pixel defining layer comprises a pixel defining part between two adjacent pixel openings, the pixel defining part has an undercut structure on a side facing the pixel opening, Wherein, the undercut structure comprises a side recess and a protruding part, the protruding part protrudes in a direction towards the pixel opening in relation to the side recess, a surface of the protruding part away from the substrate has a first roughness; The side recess comprises a first bottom close to the substrate; a first top away from the substrate; And an intermediate part between the first bottom and the first top, Wherein, the first bottom and the protruding part are in the same layer; and The first top away from the surface of the substrate has a second roughness, the first roughness is less than the second roughness.

31. A display panel, wherein, A display substrate comprising any one of claims 1-30.

32. A display device comprising: A display panel comprising the display substrate of any one of claims 1-30 or the display panel of claim 31.

Images