Display substrate and manufacturing method therefor, and display apparatus

Abstract

Provided in the present disclosure are a display substrate and a manufacturing method therefor, and a display apparatus. The display substrate (10) comprises: a base substrate (100), a pixel defining layer (110), and a plurality of light-emitting devices (120), wherein the pixel defining layer (110) comprises a plurality of pixel openings (114); the light-emitting devices (120) each comprise a first electrode (121), an organic light-emitting functional layer (122) and a second electrode (123), which are arranged in a stacked manner; protruding structures (130) which surround the pixel openings (114) are arranged on the peripheries of upper ports of the pixel openings (114); and the protruding structures (130) are configured to block leakage paths from the first electrode (121) exposed from the pixel openings (114) to an interval between adjacent light-emitting devices (120).

Description

Display substrate and manufacturing method thereof, and display device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 2023109344672, filed on July 27, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the field of display technology, and in particular to a display substrate and a preparation method thereof, and a display device. Background Art

[0004] Micro-OLED (Micro Organic Light-Emitting Diode) microdisplays are widely used in display products due to their self-luminescence, thinness, light weight, wide viewing angle, fast response time, high luminous efficiency, ease of achieving high PPI (pixel density), and low power consumption. However, Micro-OLED microdisplays still have some issues that affect display quality, such as cross-color interference between pixels.

[0005] Summary of the Invention

[0006] According to the first aspect of the present disclosure, a display substrate is provided, comprising: a base substrate; a pixel defining layer located on the base substrate, the pixel defining layer comprising a plurality of pixel openings; and a plurality of light-emitting devices, each of the light-emitting devices being located at one of the pixel openings, the light-emitting devices comprising a first electrode, an organic light-emitting functional layer and a second electrode arranged in a stacked manner, the first electrode being separated in a spacing region between adjacent light-emitting devices, the organic light-emitting functional layer covering the pixel opening and extending to the spacing region; wherein at least a portion of the first electrode is exposed at a lower port of the pixel opening, a protruding structure surrounding the pixel opening is provided at the periphery of an upper port of the pixel opening, the protruding structure being located between the pixel opening and the spacing region, the material of the protruding structure being an insulating material, and the protruding structure being configured to block a leakage path from the first electrode exposed from the pixel opening to the spacing region.

[0007] According to the second aspect of the present disclosure, a display substrate is provided, comprising: a base substrate; a pixel defining layer located on the base substrate, the pixel defining layer comprising a plurality of pixel openings; and a plurality of light-emitting devices, each of the light-emitting devices being located at one of the pixel openings, the light-emitting devices comprising a first electrode, an organic light-emitting functional layer and a second electrode arranged in a stacked manner, the first electrode being separated in a spacing region between adjacent light-emitting devices, the organic light-emitting functional layer covering the pixel opening and extending to the spacing region; wherein at least a portion of the first electrode is exposed at the lower port of the pixel opening, a protruding structure surrounding the pixel opening is provided at the periphery of the upper port of the pixel opening, the protruding structure being formed by a stack of insulating polymers generated during the etching of the pixel opening, and the protruding structure being configured to block the leakage path from the first electrode exposed from the pixel opening to the spacing region.

[0008] According to a third aspect of the present disclosure, a display device is further provided, comprising the display substrate provided by the first aspect or the second aspect of the present disclosure.

[0009] According to the fourth aspect of the present disclosure, a method for preparing a display substrate is also provided, the method comprising: providing a base substrate; forming first electrodes of a plurality of light-emitting devices on the base substrate, the first electrodes being separated in the spacing area between adjacent light-emitting devices; forming a pixel defining layer on the first electrode, the pixel defining layer having a plurality of pixel openings, each of the pixel openings corresponding to one light-emitting device, at least a portion of the first electrode of the corresponding light-emitting device being exposed at the lower port of the pixel opening, a protruding structure surrounding the pixel opening being provided at the periphery of the upper port of the pixel opening, the material of the protruding structure being an insulating material; forming an organic light-emitting functional layer of the plurality of light-emitting devices on the pixel defining layer, the organic light-emitting functional layer covering the pixel opening and extending to the spacing area, the protruding structure being configured to block the leakage path from the first electrode exposed from the pixel opening to the spacing area; and forming second electrodes of the plurality of light-emitting devices on the organic light-emitting functional layer.

[0010] The above description is only an overview of the technical solutions provided by some embodiments of the present disclosure. In order to more clearly understand the technical means of the embodiments of the present disclosure, they can be implemented in accordance with the contents of the specification. In order to make the embodiments of the present disclosure more obvious and easy to understand, the specific implementation methods of the embodiments of the present disclosure are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0012] FIG1 shows a leakage path diagram of a display substrate according to some embodiments of the present disclosure;

[0013] FIG2 shows a schematic cross-sectional view of a display substrate according to some embodiments of the present disclosure;

[0014] FIG3 shows a schematic diagram of pixel arrangement of a display substrate according to some embodiments of the present disclosure;

[0015] FIG4 shows a schematic plan view of a protrusion structure according to some embodiments of the present disclosure;

[0016] FIG5 shows a schematic structural diagram of a light-emitting device according to some embodiments of the present disclosure;

[0017] FIG6 shows a plan view micrograph of a pixel opening according to some embodiments of the present disclosure;

[0018] FIG7 shows a cross-sectional micrograph of a pixel opening according to some embodiments of the present disclosure;

[0019] FIG8 shows a flow chart of a method for preparing a display substrate according to some embodiments of the present disclosure;

[0020] FIG9 shows a schematic diagram of a patterned photoresist layer after forming some embodiments of the present disclosure;

[0021] FIG10 shows a schematic diagram after dry etching according to some embodiments of the present disclosure;

[0022] FIG11 shows a schematic diagram of some embodiments of the present disclosure after photoresist is removed; and

[0023] FIG12 shows a schematic diagram of a display device according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0024] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0025] It should be noted that the term "plurality" used herein includes two or more than two. "Include" or "comprising" and similar expressions mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0026] It will be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present therebetween.

[0027] Micro-OLED (micro organic light-emitting diode) microdisplay devices are widely used in display products, such as wearable VR (Virtual Reality) devices and AR (Augmented Reality) devices. However, the inventors discovered during actual production that Micro-OLED (micro organic light-emitting diode) microdisplay devices suffer from cross-color interference between pixels, which affects the display quality. Therefore, it is necessary to specifically improve this cross-color interference problem to enhance the display quality.

[0028] FIG1 shows a leakage path diagram of a display substrate of some embodiments of the present disclosure. As shown in FIG1 , the inventors have analyzed and found that one of the causes of the above-mentioned cross-color interference problem is that the first electrode AN (such as the anode) in the display substrate 01 is a patterned design, and the ideal current path is perpendicular to the direction of the organic light-emitting functional layer EL covered in the pixel opening PL. However, in actual application scenarios, since the distance d1 between the pixel opening PL and the space area between pixels in the Micro-OLED micro-display device is relatively close, for example, the distance d1 can be as low as the order of microns (μm). Therefore, after the first electrode AN is energized, in the lateral direction, the space area between the pixels is easily conductive due to leakage of the first electrode AN, that is, a leakage circuit is formed between the first electrode AN and the space area (such as the leakage path RL shown in FIG1 ), causing the organic light-emitting functional layer EL covered between adjacent pixels to conduct and emit light, thereby causing cross-color problems between pixels and affecting the display effect.

[0029] Figure 1 shows 10 exemplary light rays, L1-L10. L1, L2, L5, L6, L9, and L10 are normal light rays emitted from each pixel. L3, L4, L7, and L8 are crosstalk light rays emitted due to the aforementioned leakage current, which causes the organic light-emitting functional layer in the area between pixels to emit light. As shown in Figure 1, L3 is emitted sequentially through the red filter unit CF_R and the blue filter unit CF_B, L4 is emitted sequentially through the blue filter unit CF_B and the red filter unit CF_R, L7 is emitted sequentially through the green filter unit CF_G and the red filter unit CF_R, and L8 is emitted sequentially through the red filter unit CF_R and the green filter unit CF_G. This can cause crosstalk between pixels, affecting the display quality.

[0030] Therefore, some embodiments of the present disclosure provide a display substrate, a preparation method thereof, and a display device. By setting an insulating protrusion structure surrounding the pixel opening at the periphery of the upper port of the pixel opening, the protrusion structure is located between the pixel opening and the spacing area of ​​the adjacent light-emitting device. It can effectively block the leakage path from the first electrode exposed at the pixel opening to the pixel spacing area, which is beneficial to reducing the light cross-color interference between pixels to improve the display effect.

[0031] Below, the display substrate provided by some embodiments of the present disclosure is described in detail with reference to the accompanying drawings.

[0032] FIG2 shows a schematic cross-sectional view of a display substrate according to some embodiments of the present disclosure. As shown in FIG2 , some embodiments of the present disclosure provide a display substrate 10, which may include: a base substrate 100, a pixel defining layer 110 located on the base substrate 100, and a plurality of light-emitting devices 120. The pixel defining layer 110 includes a plurality of pixel openings 114, with each light-emitting device 120 located at a pixel opening 114. The light-emitting device 120 includes a first electrode 121, an organic light-emitting functional layer 122, and a second electrode 123, which are stacked. The first electrode 121 is separated in the space between adjacent light-emitting devices 120, and the organic light-emitting functional layer 122 covers the pixel opening 114 and extends to the space between adjacent light-emitting devices 120. At least a portion of the first electrode 121 is exposed at the lower end of the pixel opening 114. A protruding structure 130 surrounding the pixel opening 114 is provided at the periphery of the upper end of the pixel opening 114. The protruding structure 130 is located between the pixel opening 114 and the spacing area of ​​the adjacent light-emitting device 120. The protruding structure 130 is made of insulating material and is configured to block the leakage path from the first electrode 121 exposed at the pixel opening 114 to the above-mentioned spacing area.

[0033] It should be noted that the lower end of the pixel opening 114 is the end relatively close to the substrate 100, and the upper end of the pixel opening 114 is the end relatively far from the substrate 100. For example, as shown in FIG2 , the edge line of the first electrode 121 can be used as a dividing line to define the area of ​​each light-emitting device 120, thereby defining the spacing area between adjacent light-emitting devices 120. Of course, in other embodiments, the spacing area between adjacent light-emitting devices 120 can also be defined in other ways. For example, the pixel opening 114 can be used to define the light-emitting area of ​​the light-emitting device 120, and the area between adjacent pixel openings 114 can be used as the spacing area between the light-emitting devices 120. This embodiment is not limited to this.

[0034] In the embodiment shown in FIG2 , a raised structure 130 surrounding the pixel opening 114 is provided at the periphery of the upper end of the pixel opening 114. The raised structure 130 is made of an insulating material, which effectively blocks the leakage path from the first electrode 121 exposed at the pixel opening 114 to the gap between adjacent light-emitting devices 120. This helps reduce the risk of light emission from the organic light-emitting functional layer 122 in the pixel gap area, reduces cross-color interference between pixels, and improves the display effect. For example, the leakage path RL shown in FIG1 is blocked by the raised structure 130, which effectively prevents the pixel gap area from emitting light due to leakage current from the first electrode 121 (such as light L3, L4, L7, and L8 shown in FIG1 ), helping to improve the cross-color interference problem between pixels.

[0035] FIG3 shows a schematic diagram of the pixel arrangement of the display substrate 10 of some embodiments of the present disclosure, and FIG2 may be a cross-sectional view along AA of FIG3 . For example, as shown in FIG3 , the display substrate 10 may include: a plurality of repeated pixel units P, each pixel unit P includes a plurality of sub-pixels, and each sub-pixel emits light of one color. Each sub-pixel is provided with the above-mentioned light-emitting device 120. For example, each pixel unit P may include: two green sub-pixels G, a red sub-pixel R and a blue sub-pixel B, each sub-pixel corresponding to a light-emitting device 120 and a pixel opening 114. The pixel opening 114 corresponding to each sub-pixel is surrounded by a circle of raised structures 130. It should be noted that the pixel arrangement and sub-pixel shape shown in FIG3 are for illustration only. In other embodiments, other arrangements may be adopted, and this embodiment does not limit this.

[0036] FIG4 is a schematic plan view of a protrusion structure 130 according to some embodiments of the present disclosure. FIG4 takes the single pixel unit P shown in FIG3 as an example, where KG represents the orthographic projection area of ​​the upper end of the pixel opening 114 corresponding to the green sub-pixel G on the substrate 100, KR represents the orthographic projection area of ​​the upper end of the pixel opening 114 corresponding to the red sub-pixel R on the substrate 100, and KB represents the orthographic projection area of ​​the upper end of the pixel opening 114 corresponding to the blue sub-pixel B on the substrate 100.

[0037] As shown in FIG4 , in some embodiments of the present disclosure, the orthographic projection 1301 of the protruding structure 130 on the substrate 100 can be a closed ring, that is, a circle of anti-leakage protection structure is formed at the edge of the upper end of the pixel opening 114, isolating the leakage path between the first electrode 121 and the spacing area of ​​the adjacent light-emitting device 120, and preventing the organic light-emitting functional layer 122 covered by the pixel spacing area from conducting and emitting light. It should be noted that the shape of the closed ring shown in FIG4 is only an example, and the planar shape of the closed ring can be determined according to the orthographic projection shape of the upper end of the pixel opening 114 on the substrate 100. For example, it can be a triangular ring, a prismatic ring, a rectangular ring, a trapezoidal ring, a pentagonal ring, a regular hexagonal ring, a circular ring, or an elliptical ring. It should also be noted that if the orthographic projection shape of the protruding structure 130 on the base substrate 100 is a regular hexagonal ring, it means that the shape of the orthographic projection is roughly a regular hexagonal ring. For example, it can be a standard regular hexagonal ring, or it can be a regular hexagonal ring with chamfers, serrations or rounded corners. This embodiment does not impose any restrictions on this.

[0038] In some embodiments of the present disclosure, the ratio of the closed loop width d2 to the spacing width D between adjacent light-emitting devices 120 (d2:D) can be between one-fiftieth and one-two-hundredth. For example, d2:D can be 1:50, 1:100, 1:150, or 1:200. In some embodiments of the present disclosure, the closed loop width d2 can be between 10 and 30 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, or 30 nm, to fully isolate the leakage path.

[0039] In some embodiments of the present disclosure, affected by the process, the distance d3 between the raised structure 130 and the pixel opening 114 it surrounds can be 10 to 30 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm. The closer the distance between the raised structure 130 and the pixel opening 114, the better the raised structure 130 can increase the physical insulation height of the pixel defining layer 110, and the earlier it can block the leakage path from the first electrode 121 exposed at the pixel opening 114 to the spacing area between adjacent light-emitting devices 120, which is beneficial to further reduce the light emission of the organic light-emitting functional layer 122 between pixels, thereby reducing crosstalk interference between pixels. The farther the raised structure 130 is from the pixel opening 114, the weaker the leakage resistance blocking effect, and the leakage may jump over the raised structure 130 and continue to transmit.

[0040] Figure 5 shows a schematic structural diagram of a light-emitting device 120 according to some embodiments of the present disclosure. As shown in Figure 5, the light-emitting device 120 may include a first electrode 121, an organic light-emitting functional layer 122, and a second electrode 123, which are sequentially stacked in a direction away from the base substrate 100. For example, the light-emitting device 120 may be an organic light-emitting diode, and the organic light-emitting functional layer 122 may include an organic light-emitting layer 210 and an organic functional layer.

[0041] In some embodiments of the present disclosure, the organic light-emitting layer 210 can be divided into light-emitting layers of different colors, such as a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer. The structure of the organic light-emitting layer 210 is determined according to the light-emitting color of the light-emitting device 120 in the actual application scenario, and this embodiment does not limit this. In some embodiments of the present disclosure, the light-emitting device 120 can be a white light-emitting device. In this case, the organic light-emitting layer 210 can include: a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer to form a composite white light. Of course, for a red light-emitting device 120, the organic light-emitting layer 210 can include a red light-emitting layer; for a green light-emitting device, the organic light-emitting layer 210 can include a green light-emitting layer; for a blue light-emitting device, the organic light-emitting layer 210 can include a blue light-emitting region device.

[0042] In some embodiments of the present disclosure, the organic functional layer may include one or more of a hole injection layer, a hole transport layer, an electron blocking layer, an electron injection layer, an electron transport layer, and a hole blocking layer.

[0043] One of the first electrode 121 and the second electrode 123 is an anode, and the other is a cathode. In some embodiments of the present disclosure, as shown in FIG5 , the first electrode 121 is an anode, the second electrode 123 is a cathode, and the organic functional layer may include: a hole injection layer 221 and a hole transport layer 222 located between the first electrode 121 and the organic light-emitting layer 210, and an electron transport layer 223 and an electron injection layer 224 located between the organic light-emitting layer 210 and the second electrode 123. It should be noted that the structure shown in FIG5 is only an example. In other examples, the organic functional layer may also include more or fewer film layers than in FIG5 , and this embodiment is not limited to this.

[0044] The first electrode 121 of each light-emitting device 120 is separated within the spacing region between adjacent light-emitting devices 120, that is, the first electrodes 121 of each light-emitting device 120 are spaced apart from each other. The first electrode 121 of each light-emitting device 120 corresponds to a pixel opening 114, and at least a portion of the first electrode 121 is exposed at the lower end of the pixel opening 114. For example, the orthographic projection of the first electrode 121 on the substrate 100 can be extended outward by one circle relative to the orthographic projection of the lower end of the pixel opening 114 on the substrate 100, and the orthographic projection of the protrusion structure 130 on the substrate 100 can be located within the aforementioned extended region. At least a portion of the organic light-emitting functional layer 122 is located within the corresponding pixel opening 114 and is electrically connected to the corresponding first electrode 121. For example, the second electrode 123 of each light-emitting device 120 can be provided as a single layer, forming an integrated structure.

[0045] The anode serves as a connection layer for the forward voltage of the organic light-emitting device 120 and has good electrical conductivity and a high work function value. For example, for a top-emitting organic light-emitting device, the anode may include a metal film layer and a transparent conductive material with a high work function. The transparent conductive material may include indium tin oxide (ITO), indium zinc oxide (IZO), etc. Exemplarily, the first electrode 121 is the anode, and the structure of the first electrode 121 may be a composite structure composed of a titanium (Ti) film / titanium nitride film (TiN) / aluminum (Al) film / titanium nitride film (TiN) / ITO film stacked in sequence, or a composite structure composed of Ti / Al / Ti / ITO.

[0046] The cathode, serving as the connection layer for the negative voltage of the organic light-emitting device 120, has good electrical conductivity and a low work function. The material can be determined based on the actual application scenario. For example, for a top-emitting organic light-emitting device, the cathode can be made of a transparent conductive material, or a metal material with a low work function, such as lithium, magnesium, calcium, strontium, aluminum, or indium. Alternatively, it can be made of an alloy of one of these low-work-function metal materials with copper, gold, or silver. For example, for a bottom-emitting device, the cathode can be made of a metal material with a low work function.

[0047] In some embodiments of the present disclosure, the structure of the pixel defining layer 110 is not limited. For example, the pixel defining layer 110 can be a single-layer structure or a multi-layer composite structure. For example, the pixel defining layer 110 can include multiple stacked inorganic film layers, and the pixel opening 114 extends through the multiple stacked inorganic film layers. Among the multiple stacked inorganic film layers, the film layer farthest from the base substrate 100 is referred to as the top film layer.

[0048] In some embodiments of the present disclosure, the thickness ratio (h1:h2) of the protruding structure 130 to the top film layer in a direction perpendicular to the base substrate 100 can be between one-ninth and one-third. For example, h1:h2 can be 1:9, 1:6, or 1:3. For example, the thickness h1 of the protruding structure 130 in a direction perpendicular to the base substrate 100 can be between 100 and 300 angstroms, such as 100 angstroms, 200 angstroms, or 300 angstroms.

[0049] In some embodiments of the present disclosure, as shown in FIG2 , the pixel defining layer 110 may include: a first inorganic film layer 111, a second inorganic film layer 112, and a third inorganic film layer 113 sequentially arranged in a direction away from the base substrate 100. The pixel opening 114 penetrates the first inorganic film layer 111, the second inorganic film layer 112, and the third inorganic film layer 113. In this case, the third inorganic film layer 113 is the top film layer. For example, the first inorganic film layer 111 and the third inorganic film layer 113 may be silicon oxide layers (SiO x ), the second inorganic film layer 112 may be a silicon nitride layer (SiN x For example, a silicon oxide layer (SiO x ) can include silicon dioxide (SiO2) and / or silicon monoxide (SiO), silicon nitride layer (SiN x ) materials may include: SiN.

[0050] Of course, in other examples, the pixel defining layer 110 may also include more or fewer film layers compared to Figure 2. For example, it may also include four inorganic film layers, such as a silicon oxide layer, an aluminum oxide layer, a silicon nitride layer, and a silicon oxide layer stacked in sequence. This embodiment does not limit this.

[0051] As shown in Figure 2, to space the first electrodes 121 of adjacent light-emitting devices 120 apart, the film layer of the first electrode 121 is patterned, and electrode partitioning grooves 1211 are formed in the region separating adjacent light-emitting devices 120. The first inorganic film layer 111 of the pixel defining layer 110 also serves as a lateral height coverage (LHC) to fill the electrode partitioning grooves 1211.

[0052] For example, as shown in FIG2 , the pixel defining layer 110 may further include an isolation trench 115 located in the spacer region between adjacent light-emitting devices 120 . For example, the isolation trench 115 may be configured to isolate the hole injection layer 221 and the hole transport layer 222 in the organic light-emitting functional layer 122 extending into the spacer region, thereby further reducing lateral leakage and improving cross-color phenomenon between pixels. For example, the isolation trench 115 may be an undercut structure, i.e., an open trench with a top dimension smaller than the bottom dimension as shown in FIG2 .

[0053] In some embodiments of the present disclosure, the pixel opening 114 is formed by a dry etching process such as a plasma etching process. The above-mentioned raised structure 130 can be formed by the accumulation of an insulating polymer (polymer) formed when etching the pixel opening 114 by the dry etching process. In this case, the raised structure 130 is a byproduct of the process of dry etching the thin film of the pixel defining layer 110 to form the pixel opening 114, and no additional materials, machines, and processes are required. In addition, the raised structure 130 can be prepared synchronously with the pixel opening 114 of the pixel defining layer 110 through photolithography and dry etching processes, and is a self-aligned structure without overlay deviation.

[0054] For example, if the pixel defining layer 110 is an inorganic insulating film, the dry etching process may employ a plasma etching process. Plasma etching utilizes a high-frequency glow discharge reaction to activate reactive gases into active species, such as atoms or free radicals. These active species diffuse to the area to be etched, react with the material being etched, and form volatile reactants that are then removed.

[0055] It should be noted that there are two types of plasma dry etching: (1) physical bombardment etching; (2) chemical etching. In the dry etching menu interface of the plasma etching equipment, you can adjust the process parameters of the etching menu to decide whether to use physical bombardment etching or chemical etching as the main method.

[0056] The etching of the pixel opening 114 in the pixel defining layer 110 can be primarily performed by plasma bombardment etching, i.e., primarily by physical bombardment etching. The plasma bombards the patterned photoresist layer (e.g., photoresist) and the top film layer, such as SiO2, not blocked by the photoresist layer. The photoresist is thinnest at the sides, and the side photoresist is consumed by the plasma bombardment, exposing the SiO2 at the edge of the pixel opening 114 pattern. The side of the photoresist has the largest area in contact with the polymer produced by the plasma bombardment. Therefore, a circle of polymer produced by dry etching accumulates on the SiO2 at the edge of the pixel opening 114 formed by etching. This not only forms the pixel opening 114, but also forms a circle of anti-leakage protection structure around the pixel opening 114, i.e., the aforementioned raised structure 130.

[0057] It should be noted that when dry etching is performed mainly by chemical etching, the physical plasma bombardment of the chemical etching method is less, the polymer produced by etching will be less, and it is not easy to form polymer stacking.

[0058] For example, Figure 6 shows a planar micrograph of the pixel opening 114 of some embodiments of the present disclosure; Figure 7 shows a cross-sectional micrograph of the pixel opening 114 of some embodiments of the present disclosure. As can be seen from Figure 6, after the pixel opening 114 of the pixel defining layer 110 is formed by a dry etching process, a circle of polymer stacking is formed around the periphery of the pixel opening 114, which serves as the aforementioned raised structure 130. As can be seen from Figure 7, the cross-sectional shape of the raised structure 130 (located at the location circled in white in Figure 7) can be square or a shape similar to a square.

[0059] In some embodiments of the present disclosure, the stacked polymer is susceptible to movement due to the shrinkage stress of the photoresist layer during the removal process, resulting in a certain spacing between the raised structure 130 and the upper end of the pixel opening 114. In some embodiments of the present disclosure, by controlling the thickness of the photoresist layer remaining after etching, the shrinkage stress generated during the photoresist layer removal process can be adjusted, thereby controlling the spacing to ensure the leakage isolation performance of the raised structure 130. For example, the spacing can be controlled to between 10 and 30 nm.

[0060] In some embodiments of the present disclosure, the material composition of the protrusion structure 130 may include at least: atoms contained in the reaction gas of the dry etching process and atoms contained in the photoresist material used in the dry etching process.

[0061] The reaction gas of the plasma etching process is determined according to the material to be etched. For example, the pixel defining layer 110 may include: a stacked silicon oxide layer, a silicon nitride layer and a silicon oxide layer, and the reaction gas of the plasma etching process may be tetrafluoromethane (CF4). CF4 decomposes into a variety of neutral groups or ions, such as CF3, CF2, CF, F, C and their ions under the collision of high-energy electrons. On the one hand, these active particles bombard the surface of the etched material, and on the other hand, they also undergo chemical reactions on the surface of the etched material. At this time, since the reaction gas contains: C and F, the material composition of the above-mentioned protruding structure 130 may include: C and F. If the photoresist material is a photoresist (PR) glue, and the photoresist contains C and O, then the material composition of the protruding structure 130 may include: C and O.

[0062] In some embodiments of the present disclosure, in addition to the material components of the reaction gas and the photoresist material, the material components of the raised structure 130 may also include: at least a portion of the material components of the pixel defining layer 110, which is determined based on the structure and material of the actual pixel defining layer 110. For example, when the pixel defining layer 110 is a composite layer structure composed of multiple film layers stacked together, the polymer generated when etching the top film layer is also more likely to accumulate at the edge of the pixel opening 114. Therefore, the material components of the raised structure 130 may also include: the material components of the top film layer in the pixel defining layer 110. For example, when the top film layer is silicon oxide, silicon oxide contains Si and O. In this case, the material components of the raised structure 130 may also include: Si and O.

[0063] In some embodiments of the present disclosure, the reaction gas of the plasma etching process is CF4, the photoresist material used is photoresist, and when the top film layer of the pixel defining layer 110 is silicon oxide, the material composition of the polymer produced by dry etching can include at least: C, F, Si and O, which is an insulating material, that is, the material composition of the above-mentioned protruding structure 130 can include at least: C, F, Si and O.

[0064] In some embodiments of the present disclosure, the display substrate 10 can be used in the field of micro OLED display, and accordingly, the base substrate 100 can be a silicon wafer. For example, the material of the silicon wafer can be single crystal silicon, and the planar shape of the silicon wafer can be circular, or other shapes. At this time, a driving circuit layer can be made on the base substrate 100 to form a backplane including the driving circuit layer. The driving circuit layer includes: a pixel driving circuit corresponding to each light-emitting device 120. The pixel driving circuit is connected to the first electrode 121 of the light-emitting device 120 through the conductive portion 101 to drive the light-emitting device 120 to emit light.

[0065] For example, the pixel driving circuit may include electronic components such as multiple transistors and capacitors. For example, each pixel driving circuit may include three transistors and one capacitor, forming a 3T1C (i.e., one driving transistor, two switching transistors, and one capacitor). It may also include more than three transistors and at least one capacitor, such as a 4T1C (i.e., one driving transistor, three switching transistors, and one capacitor), a 5T1C (i.e., one driving transistor, four switching transistors, and one capacitor), or a 7T1C (i.e., one driving transistor, six switching transistors, and one capacitor). Among them, the transistor may be a thin film transistor (TFT), a field effect transistor (MOS), or other switching devices with the same characteristics.

[0066] Of course, in other embodiments of the present disclosure, the base substrate 100 may also be a rigid substrate such as a glass plate, a quartz plate, or a resin plate. Alternatively, the display substrate 10 may also be a flexible substrate, so that the display substrate 10 can be applied to the field of flexible displays. For example, when the display substrate 10 is a flexible substrate, the base substrate may include an organic material, such as PI (Polyimide), PET (Polyethylene Terephthalate), or PEN (Polyethylene naphthalate two formic acid glycol ester).

[0067] As shown in FIG2 , in some embodiments of the present disclosure, the display substrate 10 may further include an encapsulation layer 140, which is located on a side of the second electrode 123 of the light-emitting device 120 that is away from the base substrate 100. The encapsulation layer 140 may encapsulate the display substrate 10 to prevent external water, oxygen, etc. from invading the interior of the display substrate 10, thereby protecting components within the display substrate 10 (e.g., the organic light-emitting device).

[0068] In some embodiments, the encapsulation layer 140 may include a first encapsulation layer and a second encapsulation layer alternately stacked. For example, the first encapsulation layer and the second encapsulation layer may be made of an inorganic material such as a nitride, an oxide, an oxynitride, a nitrate, a carbide, or any combination thereof. For example, the first encapsulation layer may be formed by a chemical vapor deposition (CVD) process, such as a silicon nitride film, and the second encapsulation layer may be formed by an atomic layer deposition process, such as an aluminum oxide film, with multiple layers of silicon nitride films and multiple layers of aluminum oxide films alternately stacked.

[0069] In other embodiments, the encapsulation layer 140 may include a first encapsulation layer, a second encapsulation layer, and a third encapsulation layer stacked in sequence. The first and third encapsulation layers may be made of inorganic materials, such as silicon nitride, silicon oxide, or silicon oxynitride. Inorganic materials have high density and can prevent the intrusion of water, oxygen, and the like. For example, the first and third encapsulation layers may be formed by processes such as chemical vapor deposition.

[0070] For example, the material of the second encapsulation layer can be a polymer material containing a desiccant or a polymer material that can block water vapor, such as a polymer resin. It can also be a water-absorbing material, such as an alkali metal (such as Li or Na), an alkaline earth metal (such as Ba or Ca), or other moisture-reactive metals (such as Al or Fe); it can also be an alkali metal oxide (such as Li2O or Na2O), an alkaline earth metal oxide (such as MgO, CaO, or BaO), a sulfate (such as anhydrous MgSO4), a metal halide (such as CaCl2), or a perchlorate (such as Mg(ClO4)2). The second encapsulation layer can planarize the surface of the display substrate 10 and relieve stress in the first and third encapsulation layers. Materials such as a desiccant can be provided in the second encapsulation layer to absorb intrusive substances such as water and oxygen, thereby protecting components in the display substrate 10 (such as the organic light-emitting functional layer 122).

[0071] For example, as shown in FIG2 , in some embodiments of the present disclosure, the display substrate 10 may further include a color filter layer 160, which may be disposed on a side of the encapsulation layer 140 away from the base substrate 100. The color filter layer 160 may include a plurality of color filter units, each corresponding to a sub-pixel. For example, the red sub-pixel R corresponds to the red filter unit 162, the green sub-pixel G corresponds to the green filter unit 163, and the blue sub-pixel B corresponds to the blue filter unit 161.

[0072] As shown in FIG. 2 , in some embodiments of the present disclosure, the display substrate 10 may further include: a first planarizing layer 150 , which is disposed between the encapsulation layer 140 and the color filter layer 160 and performs a planarizing function to improve the thickness uniformity of the color filter layer 160 .

[0073] In some embodiments of the present disclosure, the display substrate 10 may further include: microlenses 180 arranged in an array. As shown in FIG2 , the array of microlens structures 180 may be disposed on the side of the color filter layer 160 away from the base substrate 100. The microlens array may be configured to converge lateral light output to increase display brightness and reduce power consumption. For example, each microlens 180 may be provided corresponding to a sub-pixel. For example, the microlens 180 may be a plano-convex lens structure, which may be obtained by spin coating a microlens material film layer, exposure, development, and thermoforming processes.

[0074] As shown in FIG. 2 , in some embodiments of the present disclosure, the display substrate 10 may further include: a second flat layer 170 . The second flat layer 170 is disposed between the color filter layer 160 and the microlens array 180 , and performs a flattening function to improve the thickness uniformity of the microlens material film layer, thereby improving the processing accuracy of the microlens array 180 .

[0075] Still referring to FIG. 2 , some embodiments of the present disclosure provide a display substrate 10, which may include: a base substrate 100, a pixel defining layer 110 located on the base substrate 100, and a plurality of light-emitting devices 120. The pixel defining layer 110 includes a plurality of pixel openings 114, and each light-emitting device 120 is located at a pixel opening 114. The light-emitting device 120 includes a first electrode 121, an organic light-emitting functional layer 122, and a second electrode 123 that are stacked. The first electrode 121 is isolated in the spacing area between adjacent light-emitting devices 120. The organic light-emitting functional layer 122 covers the pixel openings 114 and extends to the spacing area between adjacent light-emitting devices 120. At least a portion of the first electrode 121 is exposed at the lower end of the pixel opening 114. A raised structure 130 is disposed around the upper end of the pixel opening 114, surrounding the pixel opening 114. The raised structure 130 is formed by the accumulation of insulating polymer produced during the etching process of the pixel opening 114. The raised structure 130 is configured to block the leakage path from the first electrode 121 exposed by the pixel opening 114 to the space between adjacent light-emitting devices 120. It should be noted that the structure of the display substrate 10 can refer to the relevant description in the above embodiments and will not be repeated here.

[0076] FIG8 shows a flow chart of a method for preparing a display substrate 10 according to some embodiments of the present disclosure. As shown in FIG8 , some embodiments of the present disclosure provide a method for preparing a display substrate 10, which is applied to prepare the display substrate 10 provided in the above embodiments. The method may include the following steps:

[0077] Step S101, providing a substrate;

[0078] Step S102, forming first electrodes of a plurality of light-emitting devices on a base substrate, wherein the first electrodes are separated in interval regions between adjacent light-emitting devices;

[0079] Step S103: forming a pixel defining layer on the first electrode, wherein the pixel defining layer has a plurality of pixel openings, each pixel opening corresponding to a light-emitting device, wherein at least a portion of the first electrode of the corresponding light-emitting device 120 is exposed at a lower end of the pixel opening, and a raised structure surrounding the pixel opening is provided at an upper end of the pixel opening, wherein the raised structure is made of an insulating material;

[0080] Step S104, forming an organic light-emitting functional layer of a plurality of light-emitting devices on the pixel defining layer, wherein the organic light-emitting functional layer covers the pixel opening and extends to the above-mentioned spacing area, and the protrusion structure is configured to block the leakage path from the first electrode exposed from the pixel opening to the above-mentioned spacing area;

[0081] Step S105 , forming a plurality of second electrodes of light-emitting devices on the organic light-emitting functional layer.

[0082] In some embodiments of the present disclosure, the above-mentioned process of forming the pixel defining layer 110 on the first electrode 121 may include: forming a transition film layer of the pixel defining layer 110 on the first electrode 121; etching the transition film layer through a plasma etching process to form a plurality of pixel openings 114, and the insulating polymer generated by the etching process is accumulated on the periphery of the upper port of the pixel opening 114 to form a protruding structure 130.

[0083] The transition film layer can be a single-layer structure or a multi-layer composite structure. In some embodiments of the present disclosure, the transition film layer may include: a first silicon oxide film, a silicon nitride film, and a second silicon oxide film stacked in a direction away from the base substrate 100. In this case, the insulating polymer generated during the etching process of the second silicon oxide film will accumulate around the upper end of the pixel opening 114, thereby forming the above-mentioned protruding structure 130.

[0084] In some embodiments of the present disclosure, before etching the transition film layer using a plasma etching process to form multiple pixel openings 114, the above-mentioned preparation method may further include: forming a patterned photoresist layer on the transition film layer. In this case, the process of etching the transition film layer using a plasma etching process to form multiple pixel openings 114 and the protruding structure 130 may include: first etching the area not blocked by the photoresist layer using a plasma etching process to form multiple pixel openings 114 and the insulating polymer accumulated around the upper end of the pixel openings 114; then, removing the photoresist layer. Under the effect of the shrinkage stress generated by the removal of the photoresist layer, the accumulated insulating polymer will move in a direction away from the pixel openings 114, thereby forming the protruding structure 130. In some embodiments of the present disclosure, the movement distance of the insulating polymer can be controlled to be between 10 and 30 nm.

[0085] In some embodiments of the present disclosure, by controlling the thickness of the residual photoresist layer after etching, the shrinkage stress generated during the removal of the photoresist layer can be adjusted, thereby controlling the movement distance of the insulating polymer caused by the removal of the photoresist layer, that is, controlling the distance between the protruding structure 130 and the edge of the pixel opening 114, so that the protruding structure 130 has the effect of increasing the physical insulation height of the pixel defining layer 110, which is beneficial to ensuring the leakage isolation performance of the protruding structure 130.

[0086] The following describes the preparation process of the pixel opening 114 and the protruding structure 130 by taking the transition film layer of the pixel defining layer 110 as an example, in which the transition film layer includes: a first silicon oxide film 1110, a silicon nitride film 1120 and a second silicon oxide film 1130 stacked in a direction away from the base substrate 100, and the photoresist material is photoresist.

[0087] FIG9 shows a schematic diagram of some embodiments of the present disclosure after forming a patterned photoresist layer, FIG10 shows a schematic diagram of some embodiments of the present disclosure after dry etching, and FIG11 shows a schematic diagram of some embodiments of the present disclosure after removing the photoresist.

[0088] As shown in FIG. 9 , a photoresist layer 900 is spin-coated on the second silicon oxide film 1130 , such as SiO 2 , of the pixel defining layer 110 . After exposure, development, and other process steps, a pattern of pixel openings 114 is formed on the photoresist layer 900 .

[0089] Then, through a plasma etching process, the pattern on the photoresist is transferred to the transition film layer of the pixel definition layer 110, forming a pixel opening 114. During this process, plasma bombards the photoresist layer 900 and the SiO2 not covered by the photoresist layer 900. The side edges of the patterned photoresist layer 900 are sloped and relatively thin. The side photoresist is consumed by the plasma bombardment, and the SiO2 at the edge of the pixel opening 114 pattern is exposed. The contact area between the photoresist side and the polymer generated by the plasma bombardment is the largest. Therefore, a circle of polymer 1300 generated by dry etching can be deposited on the SiO2 exposed at the edge of the pixel opening 114, as shown in Figure 10. The material composition of polymer 1300 includes at least C, F, Si, and O, and is an insulating substance that can serve as an anti-leakage protection structure.

[0090] Next, the photoresist layer 900 is removed. As shown in Figure 11, during the removal of the photoresist layer 900, the polymer 1300 deposited by dry etching is subjected to the shrinkage stress of the photoresist layer 900, causing it to move, resulting in a certain distance d3 between the resulting raised structure 130 and the edge of the pixel opening 114. By controlling the thickness of the photoresist residue after etching and adjusting the shrinkage stress generated during the removal of the photoresist layer 900, the distance d3 between the resulting raised structure 130 and the edge of the pixel opening 114 can be controlled to be between 10 and 30 nm.

[0091] For example, FIG12 shows a schematic diagram of a display device according to some embodiments of the present disclosure. As shown in FIG12 , the display device 1 includes a display substrate 10 provided in any of the embodiments described above. Thus, the display device 1 has technical effects corresponding to the beneficial technical effects of the display substrate 10 described above.

[0092] The display device 1 can be any electronic product or component with a display function, such as a display screen, a mobile phone, a laptop computer, a tablet computer, a wearable display device (such as a VR device and an AR device, etc.), a television, a digital photo frame, etc.

[0093] It should be noted that the entire structure of the display device 1 is not described in detail herein. To achieve the necessary functions of the display device 1, those skilled in the art may configure other structures according to actual application scenarios, and the embodiments of the present disclosure are not limited thereto.

[0094] Some embodiments of the present disclosure provide a display substrate 10 and a method for manufacturing the same, and a display device, which may have at least one of the following beneficial effects:

[0095] (1) In the display substrate 10 provided in some embodiments of the present disclosure, the protruding structure 130 can effectively block the leakage path from the first electrode 121 exposed at the pixel opening 114 to the pixel spacing area, which is beneficial to reducing the light crosstalk interference between pixels and improving the display effect.

[0096] (2) In the display substrate 10 provided in some embodiments of the present disclosure, the raised structure 130 is formed by the accumulation of insulating polymer produced during the etching of the pixel opening 114. This is a byproduct of the dry etching process, requiring no additional materials, equipment, or process steps. Furthermore, the raised structure 130 can be fabricated simultaneously with the pixel opening 114 of the pixel defining layer 110 through photolithography and dry etching processes, resulting in a self-aligned structure with no overlay deviation.

[0097] (3) In the preparation method of the display substrate 10 provided in some embodiments of the present disclosure, the thickness of the photoresist material layer remaining after etching can be controlled to adjust the shrinkage stress generated during the removal of the photoresist material layer, so as to achieve the purpose of controlling the distance between the protruding structure 130 and the edge of the pixel opening 114, so that the protruding structure 130 can increase the physical insulation height of the pixel defining layer 110, which is beneficial to ensuring the leakage isolation performance of the protruding structure 130.

[0098] It should be noted that the drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures can refer to general designs. In the absence of conflict, the embodiments of the present disclosure and the features therein can be combined with each other to obtain new embodiments.

[0099] Although some embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the present disclosure.

Claims

1. A display substrate, comprising: substrate substrate; A pixel defining layer, located on the base substrate, the pixel defining layer comprising a plurality of pixel openings; as well as A plurality of light-emitting devices, each of which is located at one of the pixel openings, the light-emitting devices comprising a first electrode, an organic light-emitting functional layer and a second electrode which are stacked, the first electrode being separated in a spacing region between adjacent light-emitting devices, the organic light-emitting functional layer covering the pixel opening and extending to the spacing region; Among them, at least a partial area of ​​the first electrode is exposed at the lower port of the pixel opening, and a protruding structure surrounding the pixel opening is arranged at the periphery of the upper port of the pixel opening, and the protruding structure is located between the pixel opening and the spacing area. The material of the protruding structure is an insulating material, and the protruding structure is configured to block the leakage path from the first electrode exposed by the pixel opening to the spacing area.

2. The display substrate according to claim 1, wherein: The protruding structure is formed by polymer accumulation when the pixel opening is etched by a dry etching process, and the material composition of the protruding structure at least includes: the composition of the reaction gas of the dry etching process and the composition of the photoresist material used in the dry etching process.

3. The display substrate according to claim 2, wherein: The pixel defining layer includes a plurality of stacked inorganic film layers, the pixel opening penetrates the plurality of stacked inorganic film layers, and the material composition of the protruding structure also includes: the material composition of the top film layer of the pixel defining layer, wherein the top film layer is the film layer in the pixel defining layer farthest from the base substrate.

4. The display substrate according to claim 3, wherein: The pixel defining layer comprises: a first inorganic film layer, a second inorganic film layer and a third inorganic film layer arranged in sequence in a direction away from the base substrate, the third inorganic film layer is the top film layer, and the pixel opening penetrates the first inorganic film layer, the second inorganic film layer and the third inorganic film layer; The third inorganic film layer is a silicon oxide layer, and the material components of the protrusion structure include: carbon, fluorine, oxygen and silicon.

5. The display substrate according to claim 3, wherein: Along a direction perpendicular to the substrate, a thickness ratio of the protruding structure to the top film layer is between one ninth and one third.

6. The display substrate according to claim 1, wherein: Along a direction perpendicular to the substrate, the thickness of the protruding structure is between 100 and 300 angstroms.

7. The display substrate according to claim 1, wherein: The orthographic projection of the protruding structure on the substrate is a closed ring, and the width of the closed ring is between 10 and 30 nm.

8. The display substrate according to claim 1, wherein: The orthographic projection of the protruding structure on the base substrate is a closed ring, and the ratio of the ring width of the closed ring to the interval width between adjacent light-emitting devices is between one fiftieth and one two hundredth.

9. The display substrate according to claim 1, wherein: The distance between the protruding structure and the surrounding pixel opening is 10-30 nm.

10. A display substrate, comprising: substrate substrate; A pixel defining layer, located on the base substrate, the pixel defining layer comprising a plurality of pixel openings; as well as A plurality of light-emitting devices, each of which is located at one of the pixel openings, the light-emitting devices comprising a first electrode, an organic light-emitting functional layer and a second electrode which are stacked, the first electrode being separated in a spacing region between adjacent light-emitting devices, the organic light-emitting functional layer covering the pixel opening and extending to the spacing region; In which, at least a portion of the first electrode is exposed at the lower port of the pixel opening, and a protruding structure surrounding the pixel opening is arranged at the periphery of the upper port of the pixel opening, and the protruding structure is formed by the accumulation of insulating polymers generated during the etching process of the pixel opening, and the protruding structure is configured to block the leakage path from the first electrode exposed by the pixel opening to the spacing area.

11. A display device, comprising: The display substrate according to any one of claims 1 to 10.

12. A method for preparing a display substrate, comprising: providing a substrate base plate; Forming a plurality of first electrodes of the light emitting devices on the base substrate, wherein the first electrodes are separated in the interval regions between adjacent light emitting devices; A pixel defining layer is formed on the first electrode, wherein the pixel defining layer has a plurality of pixel openings, each of the pixel openings corresponds to one of the light-emitting devices, at least a portion of the first electrode of the corresponding light-emitting device is exposed at a lower end of the pixel opening, and a convex structure surrounding the pixel opening is disposed at an upper end of the pixel opening, wherein the convex structure is made of an insulating material; forming an organic light-emitting functional layer of the plurality of light-emitting devices on the pixel defining layer, wherein the organic light-emitting functional layer covers the pixel opening and extends to the spacing region, and the protruding structure is configured to block a leakage path from the first electrode exposed by the pixel opening to the spacing region; as well as Second electrodes of the plurality of light emitting devices are formed on the organic light emitting functional layer.

13. The method according to claim 12, wherein: Forming a pixel defining layer on the first electrode, comprising: forming a transition film layer of the pixel defining layer on the first electrode; and The transition film layer is etched by a plasma etching process to form the plurality of pixel openings, and the insulating polymer generated in the etching process is accumulated on the periphery of the upper port of the pixel opening to form the protruding structure.

14. The method according to claim 13, wherein: The transition film layer includes: a first silicon oxide film, a silicon nitride film and a second silicon oxide film stacked in a direction away from the substrate, and the insulating polymer generated by the etching process is accumulated on the periphery of the upper port of the pixel opening to form the protruding structure, including: The insulating polymer generated during the etching of the second silicon oxide film is accumulated at the periphery of the upper port of the pixel opening to form the protruding structure.

15. The method according to claim 13, wherein: Before etching the transition film layer by a plasma etching process to form the plurality of pixel openings, the method further includes: forming a patterned photoresist material layer on the transition film layer; The transition film layer is etched by a plasma etching process to form the plurality of pixel openings and the protruding structure, including: Etching the area not blocked by the photoresist material layer by a plasma etching process to form the plurality of pixel openings and insulating polymers deposited on the periphery of the upper ports of the pixel openings; and The photoresist material layer is removed, and under the shrinkage stress generated by removing the photoresist material layer, the deposited insulating polymer moves in a direction away from the pixel opening to obtain the protruding structure, wherein the moving distance is between 10 and 30 nm.

Images