Display substrates and their fabrication methods, display panels and display devices

Abstract

This application provides a display substrate, a method for fabricating the same, a display panel, and a display device. The display substrate includes a substrate, an auxiliary electrode located on the substrate, and sub-pixels located on the substrate. The auxiliary electrode includes a first film layer and a second film layer located on the first film layer. The first film layer is made of a conductive material. The edge of the orthographic projection of the first film layer onto the substrate is located inside the edge of the orthographic projection of the second film layer onto the substrate. The first film layer has a first protrusion structure on its surface away from the substrate, and the portion of the second film layer in contact with the first protrusion structure has a second protrusion structure. The sub-pixel includes a first electrode, an organic material layer located on the first electrode, and a second electrode located on the organic material layer. The organic material layer is interrupted at the side of the auxiliary electrode. The second electrode overlaps with the first film layer. The display panel includes the display substrate, and the display device includes the display panel.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a display substrate and its preparation method, a display panel and a display device. Background Technology

[0002] For top-emitting display panels, the cathode thickness of each sub-pixel is typically very small to improve the transmittance of light emitted by the sub-pixels. However, a smaller cathode thickness leads to higher cathode resistance and a larger voltage drop, resulting in significant differences in current between the sub-pixels in the center and edge areas of the display panel. This causes uneven brightness in the display panel, resulting in a poor user experience. Summary of the Invention

[0003] According to a first aspect of the embodiments of this application, a display substrate is provided. The display substrate includes:

[0004] Substrate;

[0005] An auxiliary electrode is located on the substrate, the auxiliary electrode comprising a first film layer and a second film layer located on the first film layer, the first film layer being made of a conductive material; the edge of the orthographic projection of the first film layer on the substrate is located inside the edge of the orthographic projection of the second film layer on the substrate; the surface of the first film layer facing away from the substrate is provided with a first protrusion structure, and the portion of the second film layer in contact with the first protrusion structure is provided with a second protrusion structure;

[0006] A sub-pixel located on the substrate, the sub-pixel includes a first electrode, an organic material layer located on the first electrode, and a second electrode located on the organic material layer; the organic material layer is disconnected at the side of the auxiliary electrode; the second electrode overlaps with the first film layer.

[0007] In one embodiment, the first protrusion structure is provided at least in the edge region of the first film layer facing away from the substrate; or, the first protrusion structure is provided at various locations on the surface of the first film layer facing away from the substrate.

[0008] In one embodiment, in the second film layer, the length of the second protrusion structure is a, the minimum thickness of the first film layer is b, the thickness of the second film layer at the second protrusion structure is c, and the thickness of the portion of the second film layer without the second protrusion structure is d; a, b, c, and d satisfy the following relationship:

[0009] b / 2≤a≤b; and / or,

[0010] d / 3≤c≤d; and / or,

[0011] 2d≤a≤4d.

[0012] In one embodiment, the display substrate includes a plurality of auxiliary electrodes, which are arranged at intervals; the distance between adjacent auxiliary electrodes ranges from 100 μm to 300 μm.

[0013] In one embodiment, the second film layer comprises a conductive material film layer or an insulating material film layer; or, the second film layer comprises a conductive material film layer and an insulating material film layer located on the side of the conductive material film layer opposite to the substrate.

[0014] In one embodiment, the first protrusion structure and the second protrusion structure correspond one-to-one, and the second protrusion structure covers the first protrusion structure corresponding to it.

[0015] In one embodiment, the length of the portion of the second film extending beyond the first film is greater than the length of the second protrusion structure.

[0016] In one embodiment, along the direction from the substrate to the second film layer, the edge of the portion of the second film layer extending out of the first film layer extends inward at an inward angle; the slope angle of the edge of the portion of the second film layer extending out of the first film layer is less than the slope angle of the first protrusion structure or less than the slope angle of the second protrusion structure.

[0017] In one embodiment, the side of the first membrane layer includes at least one bend, and the slope angle of at least one of the bends is greater than the slope angle of the first protrusion structure.

[0018] In one embodiment, along the direction from the substrate to the second film layer, the edge of the portion of the second film layer extending out of the first film layer extends inward at an inward angle; the slope angle of the edge of the portion of the second film layer extending out of the first film layer is less than the slope angle of at least one of the bends and greater than the slope angle of the first protrusion structure.

[0019] In one embodiment, the display substrate further includes a pixel driving circuit layer located between the substrate and the sub-pixel. The pixel driving circuit layer includes a third film layer and a fourth film layer located on the side of the third film layer facing away from the substrate. The material of the third film layer is a conductive material. The third film layer is disposed in the same layer as the first film layer, and the second film layer is disposed in the same layer as the fourth film layer.

[0020] In one embodiment, the pixel driving circuit layer includes capacitors and thin-film transistors;

[0021] The thin-film transistor includes a source electrode and a drain electrode. The source electrode and the drain electrode each include a first conductive film layer and a second conductive film layer located on the side of the first conductive film layer away from the substrate. The third film layer includes the first conductive film layer, and the fourth film layer includes the second conductive film layer. Alternatively, the capacitor includes a first capacitor plate and a second capacitor plate located on the side of the first capacitor plate away from the substrate. The third film layer includes the first capacitor plate, and the fourth film layer includes the second capacitor plate.

[0022] According to a second aspect of the embodiments of this application, a method for preparing a display substrate is provided, the method comprising:

[0023] Provide substrate;

[0024] A first film layer and a second film layer located on the side of the first film layer facing away from the substrate are formed on the substrate. The second film layer and the orthographic projection of the first film layer on the substrate coincide. A first protrusion structure is formed on the surface of the first film layer facing away from the substrate. A second protrusion structure is formed on the portion of the second film layer that contacts the first protrusion structure. The material of the first film layer is a conductive material.

[0025] An etching solution is used to etch the first film layer and the second film layer. The etching rate of the etching solution on the first film layer is greater than that on the second film layer, so that the edge of the orthographic projection of the first film layer on the substrate is located inside the edge of the orthographic projection of the second film layer on the substrate, thereby obtaining an auxiliary electrode including the first film layer and the second film layer.

[0026] A sub-pixel is formed on the substrate. The sub-pixel includes a first electrode, an organic material layer on the first electrode, and a second electrode on the organic material layer. The organic material layer is disconnected at the side of the auxiliary electrode. The second electrode overlaps with the first film layer.

[0027] In one embodiment, the method for fabricating the display substrate before forming sub-pixels on the substrate further includes:

[0028] A pixel driving circuit layer is formed on the substrate. The pixel driving circuit includes a third film layer and a fourth film layer. The material of the third film layer is a conductive material. The step of forming the first film layer on the substrate is performed simultaneously with the step of forming the third film layer. The step of forming the second film layer on the surface of the first film layer away from the substrate is performed simultaneously with the step of forming the third film layer.

[0029] According to a third aspect of the embodiments of this application, a display panel is provided, the display panel including the display substrate described above.

[0030] According to a fourth aspect of the embodiments of this application, a display device is provided, the display device including the display panel described above.

[0031] The main technical effects achieved by the embodiments of this application are:

[0032] The display substrate, its fabrication method, display panel, and display device provided in this application embodiment, by setting the edge of the orthographic projection of the first film layer of the auxiliary electrode on the substrate to be inside the edge of the orthographic projection of the second film layer on the substrate, the organic material layer of the sub-pixel is broken at the sidewall of the first film layer. Therefore, the second electrode of the sub-pixel and the first film layer of the auxiliary electrode can overlap, which can reduce the resistance of the second electrode, thereby reducing the voltage drop of the second electrode. This reduces the current difference between the central region and the edge region of the display substrate, improves the uniformity of display brightness in different regions of the display substrate, and helps to improve the user experience. A first protrusion is provided on the surface of the first film layer facing away from the substrate. The structure includes a second protrusion structure formed at the contact point between the second film layer and the first protrusion structure. The arrangement of the first and second protrusion structures increases the contact area between the first and second film layers, thereby increasing the interaction force between them and preventing separation. Furthermore, the increased contact area also prevents etchant from entering between the first and second film layers during etching, which could lead to over-etching or collapse of the second film layer. This improves the yield of the auxiliary electrode and ensures that the organic material layer of the sub-pixel is disconnected at the sidewall of the auxiliary electrode, thus ensuring the bonding effect between the second electrode and the first film layer of the auxiliary electrode. Attached Figure Description

[0033] Figure 1 This is a partial cross-sectional view of a display substrate provided in an exemplary embodiment of this application;

[0034] Figure 2 This is a partial cross-sectional view of a display substrate provided in another exemplary embodiment of this application;

[0035] Figure 3 This is a cross-sectional view of the auxiliary electrode of a display substrate provided in an exemplary embodiment of this application;

[0036] Figure 4 This is a partial scanning electron microscope image of a display substrate cut open according to an exemplary embodiment of this application;

[0037] Figure 5 This is a partial scanning electron microscope image of a display substrate cut open according to another exemplary embodiment of this application;

[0038] Figure 6 This is a partial scanning electron microscope image of a display substrate cut open according to another exemplary embodiment of this application;

[0039] Figure 7 This is a flowchart of a method for preparing a display substrate provided in an exemplary embodiment of this application. Detailed Implementation

[0040] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0041] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0042] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0043] The display substrate, its fabrication method, display panel, and display device according to the embodiments of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can complement or combine with each other.

[0044] This application provides a display substrate. For example... Figure 1 and Figure 2 As shown, the display substrate 100 includes a substrate 10, an auxiliary electrode 20 located on the substrate 10, and a sub-pixel 30 located on the substrate 10.

[0045] like Figures 1 to 3As shown, the auxiliary electrode 20 includes a first film layer 21 and a second film layer 22 located on the first film layer 21. The first film layer 21 is made of a conductive material. The edge of the orthographic projection of the first film layer 21 onto the substrate 10 is located inside the edge of the orthographic projection of the second film layer 22 onto the substrate 10. The surface of the first film layer 21 facing away from the substrate has a first protrusion structure 211, and the portion of the second film layer 22 that contacts the first protrusion structure 211 has a second protrusion structure 221.

[0046] The sub-pixel 30 includes a first electrode 31, an organic material layer 32 on the first electrode 31, and a second electrode 33 on the organic material layer 32. The organic material layer 32 is disconnected at the side of the auxiliary electrode 20; the second electrode 33 overlaps with the first film layer 21.

[0047] The display substrate provided in this application embodiment has an edge of the orthographic projection of the first film layer 21 of the auxiliary electrode onto the substrate 10 located inside the edge of the orthographic projection of the second film layer 22 onto the substrate 10. Therefore, the organic material layer 32 of the sub-pixel is broken at the sidewall of the first film layer 21. Consequently, the second electrode 33 of the sub-pixel 30 and the first film layer 21 of the auxiliary electrode 20 can overlap, reducing the resistance of the second electrode and thus reducing the voltage drop of the second electrode. This reduces the current difference between the central and edge regions of the display substrate, improving the uniformity of display brightness in different areas of the display substrate and enhancing the user experience. The first film layer 21 has a first protrusion structure 211 on its surface away from the substrate 10, and the second film layer 22 and the first protrusion structure 21... The contact portion forms a second protrusion structure 221. The arrangement of the first protrusion structure 211 and the second protrusion structure 221 increases the contact area between the first film layer 21 and the second film layer 22, and increases the force between the first film layer 21 and the second film layer 22, preventing the first film layer 21 and the second film layer 22 from separating. In addition, the increased contact area between the first film layer 21 and the second film layer 22 can also prevent the etching solution from entering between the first film layer 21 and the second film layer 22 during the etching of the first film layer 21, which would cause the second film layer to be over-etched or collapse. This can improve the yield of the auxiliary electrode 20, ensure that the organic material layer of the sub-pixel 30 is broken at the sidewall of the auxiliary electrode 20, and thus ensure the overlapping effect of the second electrode 33 and the first film layer 21 of the auxiliary electrode 20.

[0048] In one embodiment, substrate 10 may be a flexible substrate, and the material of the flexible substrate may include one or more of PI (polyimide), PET (polyethylene terephthalate), and PC (polycarbonate). In other embodiments, substrate 10 may be a rigid substrate, and the material of the rigid substrate may be, for example, glass, metal, plastic, etc.

[0049] In one embodiment, the display substrate 100 may include a plurality of sub-pixels 30 arranged at intervals, and the second electrode 33 of each sub-pixel 30 in the display substrate 100 may be a common electrode, that is, the second electrode 33 of each sub-pixel 30 in the display substrate 100 may be a surface electrode connected together.

[0050] In one embodiment, the organic material layer of the sub-pixel 30 includes an organic light-emitting material and an organic common layer. The organic light-emitting material layers of different sub-pixels 30 are spaced apart. The organic common layer may include at least one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. The organic light-emitting material layer and the organic common layer can be formed using a vapor deposition process. Since the edge of the orthographic projection of the first film layer 21 of the auxiliary electrode 20 onto the substrate 10 is located inside the edge of the orthographic projection of the second film layer 22 onto the substrate 10, the organic common layer formed by the vapor deposition process will break at the sidewall of the auxiliary electrode 20.

[0051] In one embodiment, the first electrode 31 and the second electrode 33 of the sub-pixel 30 can be formed by a sputtering process. The second electrode 33 formed by sputtering is continuous at the sidewall of the auxiliary electrode 20, meaning that the second electrode 33 does not break at the first film layer 21 of the auxiliary electrode 20, thus achieving overlap between the second electrode 33 and the first film layer 21. In some embodiments, the first electrode 31 can be an anode, and the second electrode 33 can be a cathode.

[0052] In one embodiment, the display substrate 100 further includes a pixel defining layer 55, on which a plurality of pixel openings 551 corresponding one-to-one with sub-pixels 30 are provided. The pixel defining layer 55 is located on the side of the first electrode 31 facing away from the substrate 10. The pixel openings 551 expose at least a portion of the corresponding first electrode 31. The organic material layer 32 of the sub-pixel 30 is partially located within the pixel openings 551 and partially located on the pixel defining layer 55.

[0053] In one embodiment, the display substrate 100 may be provided with a plurality of auxiliary electrodes 20, which are arranged at intervals. This helps to reduce the resistance of the second electrode and improve the uniformity of display brightness in different areas of the display substrate.

[0054] Furthermore, the distance between adjacent auxiliary electrodes 20 ranges from 100 μm to 300 μm. This arrangement avoids both situations where the distance between adjacent auxiliary electrodes 20 is too small, resulting in a large number of auxiliary electrodes 20 on the display substrate 100 and increased cost; and situations where the distance between adjacent auxiliary electrodes 20 is too large, resulting in too few auxiliary electrodes 20 on the display substrate 100, which would be detrimental to effectively reducing the resistance of the second electrode 33 and thus hindering the improvement of display brightness uniformity. In some embodiments, the distance between adjacent auxiliary electrodes 20 is, for example, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc.

[0055] In one embodiment, there are multiple sub-pixels 30 projecting onto the substrate 10 between the orthogonal projections of adjacent auxiliary electrodes 20 onto the substrate 10. This arrangement allows for a moderate number of auxiliary electrodes 20 on the display substrate, effectively improving the uniformity of the display brightness of the display substrate 100 without significantly increasing the cost of the display substrate. For example, the number of sub-pixels 30 projecting onto the substrate 10 between the orthogonal projections of adjacent auxiliary electrodes 20 onto the substrate 10 is five to ten.

[0056] In one embodiment, such as Figure 1 As shown, the surface of the first film layer 21 facing away from the substrate 10 has multiple first protrusion structures 211, and the second film layer 22 has second protrusion structures 221 formed at the contact positions with each of the first protrusion structures 211. Each second protrusion structure 221 corresponds to one of the first protrusion structures 211, and the second protrusion structure 221 covers the corresponding first protrusion structure 211. That is, the first protrusion structure 211 and the corresponding second protrusion structure 221 engage with each other. The more first protrusion structures 211 there are, the larger the contact area between the first film layer 21 and the second film layer 22, which helps to prevent the second film layer 22 from over-etching or collapsing, thus improving the yield of the auxiliary electrode 20. Adjacent first protrusion structures 211 are connected to form a wavy structure or a zigzag structure, and adjacent second protrusion structures 221 are connected to form a wavy structure or a zigzag structure.

[0057] In one embodiment, the slope angle α2 of the first protrusion structure 211 and the slope angle α3 of the second protrusion structure 221 may be the same or different. The slope angle of the first protrusion structure 211 refers to the angle between the line connecting the first protrusion structure 211 at its maximum distance from the substrate 10 and its minimum distance from the substrate 10, and the horizontal plane (top surface of the substrate); the slope angle of the second protrusion structure 221 refers to the angle between the line connecting the second protrusion structure 221 at its maximum distance from the substrate 10 and its minimum distance from the substrate 10, and the horizontal plane (top surface of the substrate).

[0058] In one embodiment, such as Figure 3 As shown, at least the edge region of the first film layer 21 facing away from the surface of the substrate 10 is provided with the first protrusion structure 211. A second protrusion structure 221 is formed at the position where the second film layer 22 contacts the first protrusion structure 211. Because the force between the edge region of the first film layer 21 and the second film layer 22 is often too weak, causing the edge portion of the second film layer 22 to collapse or be over-etched, providing the first protrusion structure 211 at the edge region of the first film layer 21 effectively prevents the portion of the second film layer 22 extending beyond the first film layer 21 from collapsing or being over-etched.

[0059] In other embodiments, the first protrusion structure 211 is provided at various points on the surface of the first film layer 21 facing away from the substrate 10. This arrangement helps to increase the contact area between the first film layer 21 and the second film layer 22, increase the interaction force between the first film layer 21 and the second film layer 22, and prevent the portion of the second film layer 22 that extends beyond the first film layer 21 from collapsing or being over-etched.

[0060] In one embodiment, such as Figure 3 As shown, in the second film layer 22, the length of the second protrusion structure 221 is a, the minimum thickness of the first film layer 21 is b, and the thickness of the second film layer 22 at the second protrusion structure 221 is c, which is the distance between the top of the second protrusion structure 221 away from the substrate and the top of the corresponding first protrusion structure 211 away from the substrate; the thickness of the part of the second film layer 22 without the second protrusion structure 221 is d.

[0061] In one embodiment, a and b satisfy the following relationship (1):

[0062] b / 2≤a≤b (1)

[0063] By setting a and b to satisfy the above relationship (1), the length a of the second protrusion structure 221 can be avoided from being too large, which would make the preparation difficult. It can also be avoided from the length a of the second protrusion structure 221 being too small, which would prevent the setting of the second protrusion structure 221 from effectively increasing the contact area between the first film layer 21 and the second film layer 22, and thus from effectively improving the interaction force between the first film layer 21 and the second film layer 22.

[0064] In one embodiment, c and d satisfy the following relationship (2):

[0065] d / 3≤c≤d (2)

[0066] By setting c and d to satisfy the above relationship (2), the thickness c of the second film layer 22 at the second protrusion structure 221 can be avoided from being too large, which would make the process difficult. It can also be avoided from being too small, which would prevent the setting of the second protrusion structure 221 from effectively increasing the contact area between the first film layer 21 and the second film layer 22, and thus from effectively improving the interaction force between the first film layer 21 and the second film layer 22.

[0067] In one embodiment, a and d satisfy the following relationship (3):

[0068] 2d≤a≤4d (2)

[0069] This design avoids the second film layer 22 from having too small a thickness d, which would cause the second film layer 22 to easily collapse or be over-etched, and also avoids the second film layer 22 from having too large a thickness d, which would make the manufacturing process difficult. Furthermore, it allows the length a of the second protrusion structure 221 to be moderate, making the second protrusion structure 221 easy to manufacture, and effectively increasing the contact area between the first film layer 21 and the second film layer 22.

[0070] In one embodiment, the length of the portion of the second film layer 22 extending beyond the first film layer 21 is greater than the length 'a' of the second protrusion structure 221. This configuration, with a larger portion of the second film layer 22 extending beyond the first film layer 21, facilitates the disconnection of the organic material layer of the sub-pixel 30 at the side of the auxiliary electrode, thereby ensuring that the second electrode of the sub-pixel 30 overlaps with the first film layer 21.

[0071] In one embodiment, along the direction from the substrate 10 toward the second film layer 22, the edge 222 of the portion of the second film layer 22 extending outward from the first film layer 21 extends inward at an inward angle. During etching of the second film layer 22, the top of the second film layer 22 is in contact with the etching solution for a longer time, causing the edge of the second film layer 22 to form a slope.

[0072] Furthermore, the slope angle α1 of the edge 222 of the second film layer 22 extending out of the first film layer 21 is smaller than the slope angle α2 of the first protruding structure 211 or smaller than the slope angle α3 of the second protruding structure 221. This arrangement avoids the slope angle α2 of the first protruding structure 211 or the slope angle of the second protruding structure 221 being too small, which would be detrimental to increasing the contact area between the first film layer 21 and the second film layer 22; and it also avoids the slope angle α1 of the edge 222 of the second film layer 22 extending out of the first film layer 21 being too large, making the process difficult to implement. In some embodiments, the slope angle α1 of the edge 222 of the second film layer 22 extending out of the first film layer 21 is smaller than the slope angle α2 of the first protruding structure 211 and smaller than the slope angle α3 of the second protruding structure 221.

[0073] In one embodiment, the side surface of the first film layer 21 includes at least one bend 212, and the slope angle α4 of at least one bend 212 is greater than the slope angle α2 of the first protrusion structure 211. When etching the side surface of the first film layer 21, the etching degree of the etching solution on different areas of the side surface of the first film layer 21 may vary, which will result in at least one bend 212 being formed on the side surface of the first film layer 21. Figure 3 In the illustrated embodiment, two bends 212 are formed on the side of the first film layer 21. When two or more bends 212 are formed on the side of the first film layer 21, the slope angle α4 of each bend 212 may be the same or may not be the same.

[0074] In one embodiment, the slope angle α1 of the edge of the portion of the second film layer 22 extending beyond the first film layer 21 is less than the slope angle α4 of at least one of the bent portions 212, and greater than the slope angle of the first protrusion structure 211. This manufacturing process is easy to implement.

[0075] In one embodiment, the first film layer 21 may be a single film layer or may include multiple film layers.

[0076] In one embodiment, the second film layer 22 comprises a conductive material film layer or an insulating material film layer. When the second film layer 22 comprises a conductive material film layer, the second film layer 22 can further reduce the resistance of the second electrode 33, and further improve the uniformity of the display brightness of the display substrate. Figures 1 to 3 As shown, the second film layer 22 is a single-layer film layer, and the second film layer 22 can be a conductive material film layer. Alternatively, the second film layer 22 can be an insulating material film layer.

[0077] In another embodiment, such as Figures 4 to 6 As shown, the second film layer 22 of the auxiliary electrode 20 includes a conductive material film layer 223 and an insulating material film layer 224 located on the side of the conductive material film layer 223 facing away from the substrate. The orthographic projection of the insulating material film layer 224 on the substrate 10 approximately coincides with the orthographic projection of the conductive material film layer 223 on the substrate 10. The material of the conductive material film layer 223 can be a conductive material, and the material of the second sub-film layer 224 can be an insulating material. The thickness of the insulating material film layer 224 is greater than the thickness of the conductive material film layer 223. The insulating material film layer 224 can provide tensile stress to the conductive material film layer 223 to prevent the conductive material film layer 223 from collapsing.

[0078] In one embodiment, such as Figure 1 and Figure 2As shown, the display substrate further includes a pixel driving circuit layer located between the substrate 10 and the sub-pixel 30. The pixel driving circuit layer includes multiple pixel circuits, each corresponding to a sub-pixel. Each pixel circuit is electrically connected to the first electrode 31 of the corresponding sub-pixel 30 to drive the corresponding sub-pixel 30.

[0079] The pixel circuit may include a thin-film transistor 41 and a capacitor 42. The thin-film transistor 41 includes an active layer 411, a gate electrode 412, a first electrode 413, and a second electrode 414. The first electrode 413 and the second electrode 414 may be formed in the same process step. One of the first electrode 413 and the second electrode 414 is a source electrode, and the other is a drain electrode. The pixel circuit may include multiple thin-film transistors 41, where the second electrode 414 of one thin-film transistor 41 is electrically connected to the first electrode 31 of the corresponding sub-pixel 30. The capacitor 42 includes a first capacitor plate 421 and a second capacitor plate 422 located on the side of the first capacitor plate 421 facing away from the substrate 10, with the first capacitor plate 421 and the second capacitor plate 422 disposed opposite to each other. The first capacitor plate 421 and the gate electrode 412 may be disposed on the same layer.

[0080] The pixel driving circuit layer may further include a gate insulating layer 51 located between the active layer 411 and the gate electrode 412, a capacitor insulating layer 52 located between the first capacitor plate 421 and the second capacitor plate 422, an interlayer dielectric layer 53 located on the side of the second capacitor plate 422 facing away from the substrate 10, and a planarization layer 54 located on the side of the first electrode 413 facing away from the substrate 10. The first electrode 413 and the second electrode 414 are partially located between the interlayer dielectric layer 53 and the planarization layer 54, and are connected to the active layer 411 through vias penetrating the gate insulating layer 51, the capacitor insulating layer 52, and the interlayer dielectric layer 53. The first electrode 31 is located on the planarization layer 54 and is connected to the second electrode 414 through vias penetrating the planarization layer 54.

[0081] In one embodiment, such as Figure 1 and Figure 2 As shown, the pixel driving circuit layer includes a third film layer 61 and a fourth film layer 62 located on the side of the third film layer 61 facing away from the substrate 10. The material of the third film layer 61 is a conductive material. The third film layer 61 is disposed in the same layer as the first film layer 21, and the second film layer 22 is disposed in the same layer as the fourth film layer 62. This arrangement allows the materials of the third film layer 61 and the first film layer 21 to be formed simultaneously, and the materials of the second film layer 22 and the fourth film layer 62 to be formed simultaneously, which helps to simplify the fabrication process complexity of the display substrate. The fourth film layer can be an insulating film layer, a conductive film layer, or a composite film layer including both a conductive film layer and an insulating film layer.

[0082] In one embodiment, such as Figure 1As shown, the source electrode (one of the first electrode 413 and the second electrode 414) and the drain electrode (the other of the first electrode 413 and the second electrode 414) each include a first conductive film layer 432 and a second conductive film layer 433 located on the side of the first conductive film layer 432 facing away from the substrate 10. The third film layer 61 includes the first conductive film layer 432, and the fourth film layer 62 includes the second conductive film layer 433. That is, the film material of the first conductive film layer 432 is formed simultaneously with at least a portion of the film material of the first film layer 21, and the film material of the second conductive film layer 433 is formed simultaneously with at least a portion of the film material of the second film layer 22. This simplifies the fabrication process. In some embodiments, the first conductive film layer 432 is the third film layer 61, and the second conductive film layer 433 is the fourth film layer 62. That is, the third film layer 61 and the fourth film layer 62 are single-layer films, and the first film layer 21 and the second film layer 22 are single-layer films.

[0083] Furthermore, such as Figure 1 As shown, the first electrode 413 and the second electrode 414 further include a third conductive film layer 431 located on the side of the first conductive film layer 432 facing the substrate 10. The auxiliary electrode 20 may also include a fifth film layer 23 located on the side of the first film layer 21 facing the substrate 10, and the fifth film layer 23 and the third conductive film layer 431 may be disposed in the same layer. The orthographic projection of the fifth film layer 23 of the same auxiliary electrode 20 on the substrate 10 may substantially coincide with the orthographic projection of the second film layer 22 on the substrate 10.

[0084] In some embodiments, the material of the first conductive film layer 432 may be aluminum, and the materials of the second conductive film layer 433 and the third conductive film layer 431 may be titanium.

[0085] In another embodiment, such as Figure 2 As shown, the third film layer 61 includes the first capacitor electrode 421, and the fourth film layer 62 includes the second capacitor electrode 422. That is, the film material of the first capacitor electrode 421 is formed simultaneously with at least a portion of the film material of the first film layer 21, and the film material of the second capacitor electrode 422 is formed simultaneously with at least a portion of the film material of the second film layer 22. This simplifies the manufacturing process. In some embodiments, the first capacitor electrode 421 is the third film layer 61, and the second capacitor electrode 422 is the fourth film layer 62. That is, the third film layer 61 and the fourth film layer 62 are single-layer films, and the first film layer 21 and the second film layer 22 are single-layer films.

[0086] It should be noted that, Figure 1 The illustrated embodiment is only used as an example to illustrate the configuration where the auxiliary electrode and part of the thin-film transistor are on the same layer. Figure 2The illustrated embodiment is only an example of the auxiliary electrode and capacitor having their films on the same layer. In other embodiments, the auxiliary electrode film may be disposed on the same layer as other films of the pixel driving circuit layer.

[0087] Figures 4 to 6 A partial scanning electron microscope (SEM) image of a display substrate cut open, as provided in an embodiment of this application. Figures 4 to 6 The different etching intensities of the second film layer 22 of the auxiliary electrode 20 shown result in variations in the dimensions of the portion of the second film layer 22 extending beyond the first film layer 21. Specifically, Figure 4 The portion of the second film layer 22 that extends beyond the first film layer 21 has the largest size. Figure 6 The portion of the second film layer 22 that extends beyond the first film layer 21 has the smallest size. However... Figures 4 to 6 The edge regions of the second film layer 22 of the auxiliary electrode 20 all extend beyond the first film layer 21, which allows the organic material layer of the sub-pixel 30 to be broken at the sidewall of the auxiliary electrode 20, ensuring that the second electrode 33 of the sub-pixel 30 overlaps with the first film layer 21 of the auxiliary electrode 20.

[0088] This application also provides a method for fabricating a display substrate. The fabrication process of the display substrate is described below. The "patterning process" mentioned in this application includes processes such as depositing a film layer, coating photoresist, mask exposure, development, etching, and photoresist stripping. Deposition can be performed using any one or more methods selected from sputtering, evaporation, and chemical vapor deposition; etching can be performed using any one or more methods selected from dry etching and wet etching. A "thin film" refers to a thin film made by depositing or coating a certain material on a substrate. If the "thin film" does not require a patterning process during the entire fabrication process, it can also be called a "layer." When the "thin film" requires a patterning process during the entire fabrication process, it is called a "thin film" before the patterning process and a "layer" after the patterning process. The "layer" after the patterning process contains at least one "pattern."

[0089] See Figure 7 The method for preparing the display substrate includes the following steps 110 to 140.

[0090] In step 110, a substrate is provided.

[0091] In step 120, a first film layer and a second film layer located on the side of the first film layer facing away from the substrate are formed on the substrate. The second film layer and the orthographic projection of the first film layer on the substrate coincide. A first protrusion structure is formed on the surface of the first film layer facing away from the substrate. A second protrusion structure is formed on the portion of the second film layer that contacts the first protrusion structure. The material of the first film layer is a conductive material.

[0092] In one embodiment, before the sub-pixels are formed on the substrate, the method for fabricating the display substrate further includes the following process:

[0093] A pixel driving circuit layer is formed on the substrate. The pixel driving circuit includes a third film layer and a fourth film layer. The third film layer is a conductive layer. The step of forming a first film layer on the substrate is performed simultaneously with the step of forming the third film layer. The step of forming a second film layer on the surface of the first film layer away from the substrate is performed simultaneously with the step of forming the third film layer.

[0094] This configuration allows the first and second films to be formed simultaneously with the film layer of the pixel driving circuit, which helps simplify the fabrication process.

[0095] In one embodiment, such as Figure 2 and Figure 3 As shown, the pixel driving circuit includes multiple pixel circuits, each of which may include a thin-film transistor 41 and a capacitor 42. The thin-film transistor 41 includes an active layer 411, a gate electrode 412, a first electrode 413, and a second electrode 414. The first electrode 413 and the second electrode 414 may be formed in the same process step. One of the first electrode 413 and the second electrode 414 is a source electrode, and the other is a drain electrode. The pixel circuit may include multiple thin-film transistors 41, where the second electrode 414 of one thin-film transistor 41 is electrically connected to the first electrode 31 of the corresponding sub-pixel 30. The capacitor 42 includes a first capacitor plate 421 and a second capacitor plate 422 located on the side of the first capacitor plate 421 facing away from the substrate 10. The first capacitor plate 421 and the second capacitor plate 422 are disposed opposite to each other. The first capacitor plate 421 and the gate electrode 412 may be disposed on the same layer.

[0096] In one embodiment, the process of forming the third film layer, the fourth film layer, the first film layer, and the second film layer can be as follows:

[0097] First, a first thin film is deposited on a substrate, the material of which is a conductive material.

[0098] Subsequently, the surface of the region corresponding to the auxiliary electrode of the first thin film is etched to form a first protrusion structure on the surface of the first thin film. ICP (ion beam assisted radical etching), RIE (reactive ion etching), or MERIE (magnetically enhanced reactive ion etching) can be used to etch the surface of the first thin film.

[0099] Subsequently, a second film is deposited on the first film, and the first protrusion structure causes the area where the second film contacts the first protrusion structure to form a second protrusion structure.

[0100] Subsequently, the first and second films are patterned using a patterning process to form a third film layer and a fourth film layer located on the side of the third film layer away from the substrate, as well as a first film layer and a second film layer located on the first film layer.

[0101] In this embodiment, the first thin film and the second thin film can be in direct contact. The third and fourth film layers can be the film layers of the first and second electrodes of the thin-film transistor.

[0102] In another embodiment, the process of forming the third film layer, the fourth film layer, the first film layer, and the second film layer can be as follows:

[0103] First, a first thin film is deposited on a substrate, the material of which is a conductive material.

[0104] Subsequently, the surface of the region corresponding to the auxiliary electrode of the first thin film is etched to form a first protrusion structure on the surface of the first thin film. ICP (ion beam assisted radical etching), RIE (reactive ion etching), or MERIE (magnetically enhanced reactive ion etching) can be used to etch the surface of the first thin film.

[0105] Subsequently, the first thin film is patterned using a patterning process to form a third film layer and a first film layer, with a first protrusion structure on the surface of the first film layer.

[0106] Subsequently, a second film is deposited on the first film, and the first protrusion structure causes the area where the second film contacts the first protrusion structure to form a second protrusion structure.

[0107] Subsequently, the second film is patterned using a patterning process to form the fourth film layer and the second film layer, and the surface of the second film layer is provided with a second protrusion structure.

[0108] In this embodiment, an insulating layer may be formed between the first thin film and the second thin film. The third film layer may be the first capacitor plate of the capacitor, the fourth film layer may be the second capacitor plate of the capacitor, and the insulating layer between the first thin film and the second thin film is a capacitor insulating layer. Before the step of depositing the second thin film on the first thin film, the above process may further include the following steps:

[0109] A capacitor insulating layer is formed on the side of the first thin film away from the substrate, and the capacitor insulating layer is etched to form a via that exposes the first film layer, and the size of the via is slightly larger than the size of the first film layer below it.

[0110] In one embodiment, before forming a second film layer located on the side of the first film layer facing away from the substrate, the method for fabricating the display substrate further includes:

[0111] At least the area of ​​the first film layer surface located between the edge region and the center region is etched to form the first protrusion structure; or, the surface of the first film layer facing away from the substrate is etched to form the first protrusion structure.

[0112] The above steps can result in the final auxiliary electrode having at least the first protrusion structure 211 on the edge region of the first film layer 21 away from the surface of the substrate 10, or having the first protrusion structure 211 at all locations on the surface of the first film layer 21 away from the substrate 10.

[0113] In this step, if the first film and the second film are etched simultaneously, the step of etching the surface of the first film layer is performed before the patterning process of the first film and the second film. Etching the surface of the first film layer is also etching the area corresponding to the first film layer of the first film and the first film layer of the auxiliary electrode.

[0114] In step 130, an etching solution is used to etch the first film layer and the second film layer. The etching rate of the etching solution on the first film layer is greater than the etching rate on the second film layer, so that the edge of the orthographic projection of the first film layer on the substrate is located inside the edge of the orthographic projection of the second film layer on the substrate, thereby obtaining an auxiliary electrode including the first film layer and the second film layer.

[0115] In one embodiment, the difference between the etching rate of the etching solution on the first film layer and the etching rate of the etching solution on the second film layer is greater than 2 μm / min. This setting helps to make the distance between the sidewall of the second film layer of the final auxiliary electrode and the sidewall of the first film layer larger, thereby helping to break the organic material layer of the sub-pixel at the sidewall of the second film layer.

[0116] In step 140, a sub-pixel is formed on the substrate. The sub-pixel includes a first electrode, an organic material layer on the first electrode, and a second electrode on the organic material layer. The organic material layer is disconnected at the side of the auxiliary electrode. The second electrode overlaps with the first film layer.

[0117] In one embodiment, an organic material layer can be formed using a vapor deposition process, and a first electrode and a second electrode can be formed using a sputtering process. This allows the organic material layer to be broken at the side of the auxiliary electrode, while the second electrode remains continuous at the side of the auxiliary electrode, enabling the second electrode to overlap with the sidewall of the first film layer of the auxiliary electrode.

[0118] The display substrate and the method for preparing the display substrate provided in the embodiments of this application belong to the same inventive concept. Related details and descriptions of the effects can be found in each other, and will not be repeated here.

[0119] This application provides a display panel. The display panel includes the display substrate described in any of the above embodiments.

[0120] In one embodiment, the display panel further includes an encapsulation layer located on the side of the display substrate facing away from the substrate. The encapsulation layer may be a thin-film encapsulation layer, comprising alternating inorganic and organic layers, with the inorganic layer being the topmost layer. For example, the encapsulation layer may include two inorganic layers and an organic layer located between the two inorganic layers.

[0121] In one embodiment, the display panel further includes a cover plate located on the side of the encapsulation layer opposite to the substrate. The cover plate may be a glass cover plate.

[0122] This application also provides a display device, which includes the display panel described above. The display device may further include a housing, in which the display panel may be embedded.

[0123] The display device in this embodiment can be any product or component with display function, such as electronic paper, mobile phone, tablet computer, television, laptop computer, digital photo frame, or navigator.

[0124] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0125] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0126] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A display substrate, characterized in that, include: Substrate; An auxiliary electrode located on the substrate, the auxiliary electrode comprising a first film layer and a second film layer located on the first film layer, wherein the material of the first film layer is a conductive material; The edge of the orthographic projection of the first film layer on the substrate is located inside the edge of the orthographic projection of the second film layer on the substrate; the surface of the first film layer facing away from the substrate has a first protrusion structure, and the portion of the second film layer in contact with the first protrusion structure has a second protrusion structure; the side surface of the first film layer includes at least one bend, and the slope angle of at least one bend is greater than the slope angle of the first protrusion structure; along the direction from the substrate to the second film layer, the edge of the portion of the second film layer extending out of the first film layer extends inward at an inward angle; the slope angle of the edge of the portion of the second film layer extending out of the first film layer is less than the slope angle of at least one bend, and greater than the slope angle of the first protrusion structure; A sub-pixel located on the substrate, the sub-pixel including a first electrode, an organic material layer located on the first electrode, and a second electrode located on the organic material layer; the organic material layer is disconnected at the side of the auxiliary electrode; The second electrode overlaps with the first film layer.

2. The display substrate according to claim 1, characterized in that, The first protrusion structure is provided at least in the edge region of the first film layer away from the surface of the substrate; or, the first protrusion structure is provided at various locations on the surface of the first film layer away from the substrate.

3. The display substrate according to claim 1, characterized in that, In the second film layer, the length of the second protrusion structure is a, the minimum thickness of the first film layer is b, the thickness of the second film layer at the second protrusion structure is c, and the thickness of the portion of the second film layer without the second protrusion structure is d; a, b, c, and d satisfy the following relationship: b / 2≤a≤b; and / or, d / 3≤c≤d; and / or, 2d≤a≤4d.

4. The display substrate according to claim 1, characterized in that, The display substrate includes a plurality of auxiliary electrodes, which are arranged at intervals; the distance between adjacent auxiliary electrodes ranges from 100μm to 300μm.

5. The display substrate according to claim 1, characterized in that, The second film layer includes a conductive material film layer or an insulating material film layer; or, the second film layer includes a conductive material film layer and an insulating material film layer located on the side of the conductive material film layer opposite to the substrate.

6. The display substrate according to claim 1, characterized in that, The first protrusion structure and the second protrusion structure correspond one-to-one, and the second protrusion structure covers the first protrusion structure corresponding to it.

7. The display substrate according to claim 1, characterized in that, The length of the portion of the second film extending beyond the first film is greater than the length of the second protrusion structure.

8. The display substrate according to claim 1, characterized in that, Along the direction from the substrate to the second film layer, the edge of the portion of the second film layer extending out of the first film layer extends inward at an inward angle; the slope angle of the edge of the portion of the second film layer extending out of the first film layer is less than the slope angle of the first protrusion structure or less than the slope angle of the second protrusion structure.

9. The display substrate according to claim 1, characterized in that, The display substrate further includes a pixel driving circuit layer located between the substrate and the sub-pixel. The pixel driving circuit layer includes a third film layer and a fourth film layer located on the side of the third film layer away from the substrate. The material of the third film layer is a conductive material. The third film layer is disposed in the same layer as the first film layer, and the second film layer is disposed in the same layer as the fourth film layer.

10. The display substrate according to claim 9, characterized in that, The pixel driving circuit layer includes capacitors and thin-film transistors; The thin-film transistor includes a source electrode and a drain electrode. The source electrode and the drain electrode each include a first conductive film layer and a second conductive film layer located on the side of the first conductive film layer away from the substrate. The third film layer includes the first conductive film layer, and the fourth film layer includes the second conductive film layer. Alternatively, the capacitor includes a first capacitor plate and a second capacitor plate located on the side of the first capacitor plate away from the substrate. The third film layer includes the first capacitor plate, and the fourth film layer includes the second capacitor plate.

11. A method for preparing a display substrate, characterized in that, The method for preparing the display substrate includes: Provide substrate; A first film layer and a second film layer located on the side of the first film layer facing away from the substrate are formed on the substrate. The second film layer and the orthographic projection of the first film layer on the substrate coincide. A first protrusion structure is formed on the surface of the first film layer facing away from the substrate. A second protrusion structure is formed on the portion of the second film layer that contacts the first protrusion structure. The material of the first film layer is a conductive material. An etching solution is used to etch the first film layer and the second film layer, wherein the etching rate of the etching solution on the first film layer is greater than the etching rate on the second film layer, such that the edge of the orthographic projection of the first film layer on the substrate is located inside the edge of the orthographic projection of the second film layer on the substrate, thereby obtaining an auxiliary electrode including the first film layer and the second film layer; the side of the first film layer includes at least one bend, and the slope angle of at least one bend is greater than the slope angle of the first protrusion structure; along the direction from the substrate to the second film layer, the edge of the portion of the second film layer extending out of the first film layer extends inward at an inward angle; the slope angle of the edge of the portion of the second film layer extending out of the first film layer is less than the slope angle of at least one bend, but greater than the slope angle of the first protrusion structure; A sub-pixel is formed on the substrate. The sub-pixel includes a first electrode, an organic material layer on the first electrode, and a second electrode on the organic material layer. The organic material layer is disconnected at the side of the auxiliary electrode. The second electrode overlaps with the first film layer.

12. The method for preparing a display substrate according to claim 11, characterized in that, The method for fabricating the display substrate before forming sub-pixels on the substrate further includes: A pixel driving circuit layer is formed on the substrate. The pixel driving circuit includes a third film layer and a fourth film layer. The material of the third film layer is a conductive material. The step of forming the first film layer on the substrate is performed simultaneously with the step of forming the third film layer. The step of forming the second film layer on the surface of the first film layer away from the substrate is performed simultaneously with the step of forming the third film layer.

13. A display panel, characterized in that, The display panel includes the display substrate as described in any one of claims 1 to 10.

14. A display device, characterized in that, The display device includes the display panel as described in claim 13.

Images