Display substrate and preparation method therefor, and display apparatus

Abstract

At least one embodiment of the present disclosure provides a display substrate and a preparation method therefor, and a display apparatus. The display substrate comprises: a base substrate; a pixel defining layer, located on the base substrate and comprising a plurality of pixel openings and pixel spacing portions spacing apart the plurality of pixel openings; a plurality of sub-pixels, located on the base substrate and being in one-to-one correspondence with the plurality of pixel openings, each sub-pixel comprising a light-emitting element; isolation structures, located on surfaces of the pixel spacing portions away from the base substrate; and an inorganic material layer, located on the sides of the isolation structures away from the base substrate, wherein an auxiliary layer is disposed on the surface of the inorganic material layer away from the base substrate. The auxiliary layer can improve the leveling uniformity of an organic encapsulation thin film during formation of an organic encapsulation layer, thereby improving the structural stability of the ultimately formed light-emitting diode display panel.

Description

Display substrate, its preparation method, and display device Technical Field

[0001] Embodiments of this disclosure relate to a display substrate, a method for fabricating the same, and a display device. Background Technology

[0002] Organic light-emitting diode (OLED) displays have become a research hotspot and technological development direction for major manufacturers due to their advantages such as wide color gamut, high contrast, thin and light design, self-emissive nature, and wide viewing angle. Currently, OLED displays are widely used in various electronic products, from small items like smart bracelets, smartwatches, smartphones, and tablets to large devices like laptops, desktop computers, and televisions. Therefore, the market demand for active-matrix OLED displays is increasingly strong.

[0003] With the continuous development of display technology, people's pursuit of display quality is also increasing. To further reduce power consumption and achieve high brightness, the single-layer light-emitting element in an OLED can be replaced with a double-layer light-emitting layer, and a charge generation layer (CGL) can be added between the two layers to achieve a tandem EL design. Since a display device using a tandem EL design has two light-emitting layers, its brightness is approximately twice that of a single-layer light-emitting device. Therefore, display devices using a tandem EL design have advantages such as long lifespan, low power consumption, and high brightness.

[0004] Summary of the Invention

[0005] At least one embodiment of this disclosure provides a display substrate, a method for fabricating the same, and a display device. On one hand, the display substrate avoids crosstalk between adjacent sub-pixels caused by a highly conductive charge generation layer by setting a partition structure between adjacent sub-pixels and disconnecting the charge generation layer in the light-emitting functional layer at the location of the partition structure. Furthermore, an auxiliary layer is provided on the surface of the isolation structure away from the substrate. This auxiliary layer can improve the uniformity of the flow of the organic encapsulation film during the formation of the organic encapsulation layer, thereby improving the structural stability of the final formed LED display panel. On the other hand, since the display substrate can employ a dual-layer light-emitting (Tandem EL) design while providing an auxiliary layer on the side surface of the isolation structure, this auxiliary layer can improve the uniformity of the flow of the organic encapsulation film during the formation of the organic encapsulation layer, allowing the final encapsulation structure to block external water and oxygen from entering the light-emitting element, thus improving the lifespan of the display substrate. Therefore, when the side surface of the isolation structure of the display substrate includes an auxiliary layer, the display device including this display substrate has advantages such as long lifespan, low power consumption, high brightness, and high resolution.

[0006] At least one embodiment of this disclosure provides a display substrate, the display substrate comprising: a substrate; a pixel defining layer located on the substrate, including a plurality of pixel openings and pixel spacing portions separating the plurality of pixel openings; a plurality of sub-pixels located on the substrate, corresponding one-to-one with the plurality of pixel openings, each of the sub-pixels including a light-emitting element; an isolation structure located on the surface of the pixel spacing portions away from the substrate; and an inorganic material layer located on the side of the isolation structure away from the substrate, wherein an auxiliary layer is disposed on the surface of the inorganic material layer away from the substrate.

[0007] For example, in at least one embodiment of the display substrate provided in this disclosure, the auxiliary layer is made of a metal oxide with strong hydrophilicity.

[0008] For example, in the display substrate provided in at least one embodiment of this disclosure, the material of the auxiliary layer is titanium dioxide.

[0009] For example, in the display substrate provided in at least one embodiment of this disclosure, the auxiliary layer includes a plurality of mutually spaced sub-auxiliary structures, or the auxiliary layer is an integrally formed whole-layer structure.

[0010] For example, in a display substrate provided in at least one embodiment of this disclosure, the isolation structure includes a stacked structure formed by sequentially stacking at least one first titanium metal layer, an aluminum metal layer, and a second titanium metal layer.

[0011] For example, in a display substrate provided in at least one embodiment of this disclosure, the isolation structure includes one of the stacked structures, the first titanium metal layer is closer to the substrate than the second titanium metal layer, the number of isolation structures is multiple, and in two adjacent isolation structures, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers.

[0012] For example, in a display substrate provided in at least one embodiment of this disclosure, the isolation structure includes two stacked structures, which are a first stacked structure and a second stacked structure stacked together. The first stacked structure is closer to the substrate than the second stacked structure. The maximum distance between adjacent first stacked structures is greater than the maximum distance between adjacent second stacked structures, and the minimum distance between adjacent first stacked structures is greater than the minimum distance between adjacent second stacked structures.

[0013] For example, in the display substrate provided in at least one embodiment of this disclosure, in each of the stacked structures, the first titanium metal layer is closer to the substrate than the second titanium metal layer, the number of the isolation structures is multiple, and in two adjacent isolation structures, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers.

[0014] For example, in a display substrate provided in at least one embodiment of this disclosure, the inorganic material layer is a first inorganic encapsulation layer, and the display substrate further includes an organic encapsulation layer and a second inorganic encapsulation layer stacked on the first inorganic encapsulation layer. The first inorganic encapsulation layer, the organic encapsulation layer and the second inorganic encapsulation layer constitute an encapsulation structure, and the auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer.

[0015] For example, in a display substrate provided in at least one embodiment of this disclosure, the inorganic material layer is a protective layer, and the protective layer and the auxiliary layer are in direct contact.

[0016] For example, in a display substrate provided in at least one embodiment of this disclosure, the plurality of sub-pixels constitute a plurality of pixel units, and each pixel unit includes a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel arranged in a first direction.

[0017] For example, in a display substrate provided in at least one embodiment of this disclosure, the first color sub-pixel is a red sub-pixel, the second color sub-pixel is a green sub-pixel, and the third color sub-pixel is a blue sub-pixel.

[0018] For example, in a display substrate provided in at least one embodiment of this disclosure, a first stacked portion of a first color emitting functional layer residual structure and a cathode residual structure is provided at the end of the pixel interval adjacent to the first color sub-pixel; a second stacked portion of a second color emitting functional layer residual structure and the cathode residual structure is provided at the end of the pixel interval adjacent to the second color sub-pixel; and a third stacked portion of a third color emitting functional layer residual structure and the cathode residual structure is provided at the end of the pixel interval adjacent to the third color sub-pixel.

[0019] For example, in a display substrate provided in at least one embodiment of this disclosure, a planarization layer is further provided between the light-emitting element and the auxiliary layer.

[0020] At least one embodiment of this disclosure also provides a method for fabricating a display substrate, the method comprising: providing a substrate; forming a pixel defining layer on the substrate, wherein the pixel defining layer includes a plurality of pixel openings and pixel spacing portions separating the plurality of pixel openings; forming a plurality of sub-pixels in the plurality of pixel openings, wherein the plurality of sub-pixels correspond one-to-one with the plurality of pixel openings, and each sub-pixel includes a light-emitting element; forming an isolation structure on the surface of the pixel spacing portions away from the substrate; forming an inorganic material layer on the side of the isolation structure away from the substrate; and forming an auxiliary layer on the side of the inorganic material layer away from the substrate.

[0021] For example, in the fabrication method provided in at least one embodiment of this disclosure, forming the light-emitting element includes: sequentially forming a light-emitting functional layer and a cathode layer on the side of the pixel opening away from the substrate; forming a photoresist layer on the cathode layer; and performing a patterning process on the photoresist layer to form a photoresist retention area and a photoresist removal area, wherein the photoresist retention area corresponds to the area where the light-emitting element of the corresponding color is formed.

[0022] At least one embodiment of this disclosure also provides a display substrate, the display substrate comprising: a substrate; a pixel defining layer located on the substrate, including a plurality of pixel openings and pixel spacing portions separating the plurality of pixel openings; a plurality of sub-pixels located on the substrate, corresponding one-to-one with the plurality of pixel openings, each sub-pixel including a light-emitting element; first isolation portions disposed at both ends of the pixel defining layer; a first planarization layer disposed between the light-emitting element and the substrate, wherein the end of the first isolation portion away from the pixel opening is further away from the pixel opening than the corresponding end of the first planarization layer away from the pixel opening, and the end of the first isolation portion away from the pixel opening and the corresponding end of the first planarization layer away from the pixel opening are stacked to form an isolation structure, and an auxiliary layer is disposed on the side surface of the isolation structure.

[0023] For example, at least one embodiment of the present disclosure provides a display substrate that further includes an encapsulation structure disposed on the side of the light-emitting element away from the substrate, wherein the encapsulation structure includes a first inorganic encapsulation layer, an organic encapsulation layer and a second inorganic encapsulation layer stacked together, and the auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer.

[0024] For example, in a display substrate provided in at least one embodiment of this disclosure, the material of the auxiliary layer includes an organic material or a metal oxide that has light-absorbing properties.

[0025] For example, in the display substrate provided in at least one embodiment of this disclosure, the light-absorbing metal oxide includes at least one of molybdenum tantalum oxide, copper oxide, molybdenum oxide, and zinc oxide.

[0026] For example, in a display substrate provided in at least one embodiment of this disclosure, the light-emitting element includes a second electrode, the second electrode includes a portion disposed on the isolation structure, and the second electrode is disconnected at a position corresponding to the isolation structure.

[0027] For example, at least one embodiment of the present disclosure provides a display substrate that further includes a thin-film transistor disposed between the substrate and the light-emitting element, wherein the first electrode of the light-emitting element is electrically connected to a transition electrode through a first via structure disposed in the first planarization layer, and the transition electrode is electrically connected to the first source / drain electrode of the thin-film transistor through a second via structure disposed in the second planarization layer and the first passivation layer.

[0028] At least one embodiment of this disclosure also provides a display device, which includes the display substrate described in any of the above claims. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure.

[0030] Figures 1A to 1G illustrate the fabrication process of a display substrate;

[0031] Figure 2 is a schematic cross-sectional view of a display substrate provided in at least one embodiment of the present disclosure;

[0032] Figure 3 is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0033] Figure 4 is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0034] Figure 5A is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0035] Figure 5B is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0036] Figure 6 is a flowchart of a method for preparing a display substrate according to at least one embodiment of the present disclosure;

[0037] Figure 7 is a schematic diagram of a cross-sectional structure of a display substrate;

[0038] Figure 8 is a schematic diagram of the cross-sectional structure of another type of display substrate;

[0039] Figure 9 is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0040] Figure 10 is a schematic cross-sectional view of another display substrate provided in at least one embodiment of the present disclosure;

[0041] Figures 11 and 12 are schematic diagrams illustrating the fabrication process of the auxiliary layer in the display substrate shown in Figure 9; and

[0042] Figure 13 is a block diagram of a display device provided in at least one embodiment of the present disclosure. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0044] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0045] Unless otherwise defined, the features such as "parallel," "perpendicular," and "identical" used in the embodiments of this invention include strictly defined cases of "parallel," "perpendicular," and "identical," as well as cases involving a certain degree of error, such as "approximately parallel," "approximately perpendicular," and "approximately identical." For example, the aforementioned "approximately" may indicate that the difference between the compared objects is within 10% or 5% of the average value of the compared objects. Unless otherwise specified in the following embodiments of this invention, the quantity of a component or element is implied to mean that the component or element may be one or more, or can be understood as at least one. "At least one" refers to one or more, and "more" refers to at least two. In the embodiments of this invention, "same-layer arrangement" refers to the relationship between multiple film layers formed from the same material after undergoing the same step (e.g., a patterning process). Here, "same-layer" does not always mean that the multiple film layers have the same thickness or that the multiple film layers have the same height in a cross-sectional view.

[0046] Currently, bendable displays can be achieved using liquid crystal display (LCD) panels and organic light-emitting diode (OLED) display panels. OLED display panels are self-emissive, and fabricating OLEDs on flexible substrates makes it easier to achieve bendable displays, resulting in smaller bending radii. Therefore, the fabrication of OLED display panels, including those on flexible substrates, has attracted widespread attention from researchers in the display field.

[0047] As consumers demand increasingly diverse functionalities from organic light-emitting diode (OLED) display panels, isolation structures are incorporated into these panels to enable different functionalities. For example, during the patterning process of individual film layers in an OLED display panel (without fine photolithography), isolation structures ensure the reliability of the film layers formed during each patterning process. In automotive or electronic products requiring long lifespans, T-shaped isolation structures can block lateral crosstalk of electrons in the charge generation layer of the OLED display device.

[0048] For example, the process of fabricating a display substrate without fine photolithography includes: forming a thin-film transistor, a first electrode, and a pixel defining layer thin film on a substrate; depositing a stacked metal on the pixel defining layer thin film to form an isolation structure; forming a first photoresist on the substrate, and performing a patterning process on the first photoresist corresponding to the first color sub-pixel region to form a first photoresist pattern; etching the pixel defining layer thin film and the stacked metal using the first photoresist pattern as a mask (dry etching or wet etching) to form a first pixel opening and a first isolation structure corresponding to the first color sub-pixel; depositing a first color emitting layer thin film, a functional layer thin film, a second electrode thin film, and a first protective layer thin film layer by layer; and depositing the first color emitting layer thin film, a functional layer thin film, a second electrode thin film, and a first protective layer thin film at the location corresponding to the first color sub-pixel region. A photoresist protective layer is formed; the first color emitting layer film, functional layer film, second electrode film, and first protective layer film in the non-photoresist protected area without a photoresist protective layer are etched to form a pattern of the first color emitting layer, functional layer, second electrode, and first protective layer corresponding to the first color sub-pixel area; a second photoresist is formed on the substrate, and the second photoresist corresponding to the second color sub-pixel area is patterned to form a second photoresist pattern; the pixel defining layer film and stacked metal are etched (dry or wet) using the second photoresist pattern as a mask to form a second pixel opening and a second isolation structure corresponding to the second color sub-pixel; the second color emitting layer film, functional layer film, and second electrode film are deposited layer by layer. The process involves: forming a first color light-emitting layer and a second protective layer; forming a photoresist protective layer at a location corresponding to the second color sub-pixel region; etching the second color light-emitting layer, functional layer, second electrode, and second protective layer in the non-photoresist-protected areas (where no photoresist protective layer is provided) to form a pattern of the second color light-emitting layer, functional layer, second electrode, and second protective layer corresponding to the second color sub-pixel region; forming a third photoresist on a substrate; and performing a patterning process on the third photoresist corresponding to the third color sub-pixel region to form a third photoresist pattern; using the third photoresist pattern as a mask, etching (dry or wet etching) the pixel-defining layer and the stacked metal to form a third pixel opening and a third isolation structure corresponding to the third color sub-pixel. The process involves depositing a third-color emitting layer film, a functional layer film, a second electrode film, and a third protective layer film across the entire layer; forming a photoresist protective layer at the location corresponding to the third-color sub-pixel region; etching the third-color emitting layer film, functional layer film, second electrode film, and third protective layer film in the non-photoresist-protected areas where no photoresist protective layer is provided to form a pattern of the third-color emitting layer, functional layer, second electrode, and third protective layer corresponding to the third-color sub-pixel region; then forming a planarization layer on the entire first, second, and third protective layers, which is used to reduce stress concentration in the isolation structure; and sequentially forming a first inorganic layer for thin-film encapsulation, a first organic layer for thin-film encapsulation, and a second inorganic layer for thin-film encapsulation on the planarization layer.

[0049] For example, Figures 1A to 1G illustrate the fabrication process of a display substrate. As shown in Figure 1A, a thin-film transistor (not shown in Figure 1A), a first electrode 102, and a pixel defining layer thin film 104 are formed on a substrate 101. A stacked metal 103 is formed on the pixel defining layer thin film 104. For example, after fabricating the thin-film transistor and the first electrode on the substrate 101 according to the above-described process steps without fine photolithography, a full-surface pixel defining layer thin film is fabricated, and two or more sets of stacked metals are deposited on the pixel defining layer thin film to form an isolation structure. For example, the structure of the stacked metal makes it easier to form an undercut structure. For example, the pixel defining layer thin film can be formed using inorganic materials, and it may include one layer of inorganic material or multiple layers of inorganic material stacked together. For example, the pixel defining layer thin film may consist of one or more layers of silicon oxide, silicon nitride, and silicon oxynitride.

[0050] For example, as shown in Figure 1A, the stacked metal can be a set of stacked structures Ti / Al / Ti consisting of a first titanium metal layer Ti, an aluminum metal layer Al, and a second titanium metal layer Ti stacked sequentially. Figure 1A shows the structure of two sets of the above-mentioned stacked structures Ti / Al / Ti stacked together.

[0051] For example, as shown in Figure 1B, a first photoresist is formed on a substrate. The first photoresist corresponding to the first color sub-pixel region is patterned to form a first photoresist pattern. Using the first photoresist pattern as a mask, the pixel-defining layer film and the stacked metal are etched (dry or wet) to form a first pixel opening 106 and a first isolation structure 105 corresponding to the first color sub-pixel. In this process, dry etching is prone to over-etching. After etching the two sets of stacked metals, in addition to the upper Ti / Al / Ti stacked structure and the lower Ti / Al / Ti stacked structure each forming an undercut structure, the lower Ti / Al / Ti stacked structure has a larger opening size than the upper Ti / Al / Ti stacked structure. That is, an undercut structure is also formed between the upper and lower Ti / Al / Ti stacked structures.

[0052] For example, as shown in Figure 1B, corresponding to the first pixel opening, the lower Ti / Al / Ti stacked structure has a larger opening area than the upper Ti / Al / Ti stacked structure.

[0053] For example, as shown in FIG1C, a first color emitting functional layer film 107', a second electrode film 108', and a first protective layer film 109' are deposited in an integral layer on a substrate 101. The first color emitting functional layer film 107' and the second electrode film 108' are both broken at the positions corresponding to the first isolation structure 105, thereby causing the first color emitting functional layer film 107' formed in the first pixel opening and the first color emitting functional layer film 107' located on the first isolation structure 105 to be spaced apart to form a discontinuous structure.

[0054] For example, in the structure shown in Figure 1C, the first color emitting functional layer film 107', the second electrode film 108', and the first protective layer film 109' utilize the good shielding effect of the second electrode film 108'. The second electrode film 108' overlaps with the first isolation structure 105. While isolating the first color emitting functional layer film 107', the first isolation structure 105 can also ensure that the second electrode film 108' overlaps with the first isolation structure 105. That is, even if the second electrode film 108' is formally isolated, the second electrode film 108' is still equivalent to a whole-layer structure because the first isolation structure 105 is conductive, thus not weakening the conductivity of the entire second electrode film.

[0055] For example, as shown in FIG1D, a photoresist protective layer (not shown) is formed at a position corresponding to the first color sub-pixel region. The first color emitting functional layer film, the second electrode film and the first protective layer film in the non-photoresist protected area where no photoresist protective layer is provided are etched to form a pattern of the first color emitting functional layer 107, the second electrode 108 and the first protective layer 109 corresponding to the first color sub-pixel region.

[0056] For example, as shown in FIG1E, the process described in FIG1B to FIG1D is repeated to form a pattern corresponding to the second pixel opening 110, the second isolation structure 111, the second color light-emitting functional layer 112, the second electrode 113, and the second protective layer 114 in the second color sub-pixel region; the process described in FIG1B to FIG1D is repeated again to form a pattern corresponding to the third pixel opening 115, the third isolation structure 116, the third color light-emitting functional layer 117, the second electrode 118, and the third protective layer 119 in the third color sub-pixel region.

[0057] For example, in one example, the first color sub-pixel region is a red sub-pixel region, and the corresponding first color emissive layer 107 is a red emissive layer. The second color sub-pixel region is a green sub-pixel region, and the corresponding second color emissive layer 112 is a green emissive layer. The third color sub-pixel region is a blue sub-pixel region, and the corresponding third color emissive layer 117 is a blue emissive layer.

[0058] For example, as shown in FIG1F, a planarization layer 120 is formed on the entire surface of the substrate 101 corresponding to the first color sub-pixel region, the second color sub-pixel region and the third color sub-pixel region. The planarization layer 120 fills the first pixel opening 106, the second pixel opening 110 and the third pixel opening 115, and covers the first protective layer 109, the second protective layer 114 and the third protective layer 119.

[0059] For example, stress concentration is prone to occur due to the presence of isolation structures. Using a planarization layer to release stress can achieve a flattening effect, making it less likely for the subsequent deposition of various thin film encapsulation layers to cause problems such as accumulation and compression of the thin film encapsulation layers.

[0060] For example, as shown in FIG1G, an encapsulation structure 121 is formed on the planarization layer 120. The encapsulation structure 121 includes a first inorganic thin-film encapsulation layer, an organic thin-film encapsulation layer, and a second inorganic thin-film encapsulation layer stacked together.

[0061] For example, when an isolation structure is formed by stacking two or more sets of metal structures, voids are easily deposited in the inorganic thin film encapsulation layer during subsequent thin film encapsulation. The formation of voids is usually controlled by increasing the height of the aluminum metal layer and the lateral depth of the two titanium metal layers in the Ti / Al / Ti stacked structure.

[0062] For example, when a large number of isolation structures are set in a display panel, and inkjet printing is typically used to form the organic encapsulation film during the encapsulation process, the presence of numerous isolation structures creates an uneven surface on the organic encapsulation film. This affects the leveling effect during the curing of the organic encapsulation film, resulting in poor uniformity of the final organic encapsulation layer thickness, and even a wrinkled surface.

[0063] For example, an encapsulation layer typically includes a first inorganic thin-film encapsulation layer, a third inorganic thin-film encapsulation layer, and a fourth inorganic thin-film encapsulation layer, all stacked together. The first inorganic thin-film encapsulation layer, which provides water and oxygen barrier properties, is generally fabricated using equipment such as low-temperature plasma-enhanced chemical vapor deposition, atomic layer deposition, and sputtering to obtain thin films of silicon oxynitride, silicon nitride, silicon oxide, aluminum oxide, or titanium oxide. The organic thin-film encapsulation layer, fabricated on top of the first inorganic thin-film encapsulation layer, serves to planarize and release stress. The coverage area of ​​the organic thin-film encapsulation layer is smaller than that of the first inorganic thin-film encapsulation layer, and the fabrication process for the organic thin-film encapsulation layer can include inkjet printing, screen printing, or flash evaporation. Depending on the actual film deposition process, the thickness of the organic thin-film encapsulation layer ranges from 1.5 micrometers to 20 micrometers. The second inorganic thin-film encapsulation layer is then fabricated on top of the organic thin-film encapsulation layer. The coverage area of ​​the second inorganic thin-film encapsulation layer can be the same as or larger than that of the first inorganic thin-film encapsulation layer.

[0064] For example, depending on the structure of different organic light-emitting diode display devices, the refractive index matching of the stacked thin-film encapsulation first inorganic layer, thin-film encapsulation organic layer and thin-film encapsulation second inorganic layer in the encapsulation structure may be different. However, the embodiments of this disclosure do not limit the refractive index matching, as long as it can meet the requirements for water and oxygen barrier.

[0065] For example, the refractive index of the first inorganic layer in thin-film encapsulation ranges from 1.4 to 1.8. Depending on the actual water and oxygen barrier effect and the film-forming process, the thickness of the first inorganic layer ranges from 500 Å to 20000 Å. Depending on the actual material, the refractive index of the organic layer in thin-film encapsulation ranges from 1.4 to 1.6. The type, thickness, and manufacturing process of the second inorganic layer in thin-film encapsulation are similar to those of the first inorganic layer, and its refractive index ranges from 1.6 to 2.

[0066] The inventors of this disclosure have noted that after forming the first inorganic thin-film encapsulation layer on the structure shown in FIG1G, hydrophobic structures are easily formed in the slits between the first protective layer 109 and the second protective layer 114, and between the second protective layer 114 and the third protective layer 119. Due to the presence of the isolation structure over a large area, the leveling effect of the organic thin-film encapsulation layer is affected after printing and before curing, resulting in poor uniformity of the final organic thin-film encapsulation layer thickness.

[0067] The inventors of this disclosure also noted that an auxiliary layer can be formed on the inorganic encapsulation film before forming the organic encapsulation film. This auxiliary layer can perform the function of guiding the flow of the organic encapsulation film, thereby improving the uniformity of the flow level of the organic encapsulation film, so that the final organic encapsulation layer has a flat surface, thereby improving the structural stability of the final light-emitting diode display panel.

[0068] At least one embodiment of this disclosure provides a display substrate, which includes: a substrate, a pixel defining layer on the substrate, the pixel defining layer including a plurality of pixel openings and pixel spacing portions spaced apart from the plurality of pixel openings, a plurality of sub-pixels on the substrate, the plurality of sub-pixels corresponding one-to-one with the plurality of pixel openings, each sub-pixel including a light-emitting element, an isolation structure disposed on the surface of the pixel spacing portions away from the substrate, an inorganic material layer disposed on the side of the isolation structure away from the substrate, and an auxiliary layer disposed on the surface of the inorganic material layer away from the substrate. The auxiliary layer can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the finally formed light-emitting diode display panel.

[0069] For example, FIG2 is a schematic cross-sectional view of a display substrate provided in at least one embodiment of the present disclosure. As shown in FIG2, the display substrate 200 includes a substrate 201 and a pixel defining layer 202 located on the substrate 201. The pixel defining layer 202 includes a plurality of pixel openings 203 and pixel spacing portions 204 that space the plurality of pixel openings 203. A plurality of sub-pixels 205 are provided on the substrate 201. The plurality of sub-pixels 205 correspond one-to-one with the plurality of pixel openings 203. Each sub-pixel 205 includes a light-emitting element 206. An isolation structure 207 is provided on the surface of the pixel spacing portion 204 away from the substrate 201. An inorganic material layer 214 is provided on the surface of the isolation structure 207 away from the substrate 201. An auxiliary layer 208 is provided on the surface of the inorganic material layer 214 away from the substrate 201. The auxiliary layer 208 can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the finally formed light-emitting diode display panel.

[0070] For example, the isolation structure 207 and the auxiliary layer 208 are disposed in the display area of ​​the display substrate to, for example, block the lateral crosstalk of electrons in the charge generation layer of the light-emitting diode display device, thereby making the organic encapsulation layer of the final display substrate more uniformly leveled during the formation process.

[0071] For example, as shown in Figure 2, pixel openings 205 are disposed between two adjacent isolation structures 207. For example, the position corresponding to the leftmost pixel opening 205 is the first color sub-pixel region, which contains a first color emissive layer 209, a second electrode 210, and a protective layer 213. The position corresponding to the middle pixel opening 205 is the second color sub-pixel region, which contains a second color emissive layer 211, a second electrode 210, and a protective layer 213. The position corresponding to the rightmost pixel opening 205 is the third color sub-pixel region, which contains a third color emissive layer 212, a second electrode 210, and a protective layer 213.

[0072] For example, in one example, the first color emitting functional layer 209 is a red emitting functional layer, the second color emitting functional layer 211 is a green emitting functional layer, and the third color emitting functional layer 212 is a blue emitting functional layer. The isolation structure 207 can block crosstalk of charges generated by the charge generation layers in the emitting functional layers of different colors.

[0073] For example, as shown in Figure 2, the auxiliary layer 208 is made of a metal oxide with strong hydrophilicity. Since hydrophobic structures are easily formed at the slits between adjacent protective layers 213, the metal oxide with strong hydrophilicity can reduce the hydrophobic properties at least some locations between adjacent isolation structures 207, thereby improving the leveling properties of the subsequently formed organic encapsulation layer.

[0074] For example, in one example, the material of the auxiliary layer 208 is titanium dioxide, which is nano-titanium dioxide. For example, strong hydrophilic titanium dioxide can be deposited by atomic layer deposition or direct deposition to form the auxiliary layer. That is, by adding the auxiliary layer 208 as a flow-guiding functional layer of the organic encapsulation layer, the uniformity of the flow level of the organic encapsulation layer can be improved.

[0075] For example, as shown in Figure 2, the auxiliary layer 208 includes multiple mutually spaced sub-auxiliary structures 2081. This allows the auxiliary layer 208 to achieve the best drainage effect while minimizing its area, thereby balancing hydrophilicity and hydrophobicity. Furthermore, the thinness of the auxiliary layer 208 avoids increasing the thickness of the stacked structure and minimizes the amount of raw materials used in the auxiliary layer 208.

[0076] For example, as shown in Figure 2, the isolation structure 207 includes a stacked structure formed by sequentially stacking at least one first titanium metal layer, an aluminum metal layer, and a second titanium metal layer.

[0077] For example, as shown in Figure 2, the isolation structure 207 includes a stacked structure, with the first titanium metal layer closer to the substrate than the second titanium metal layer. There are multiple isolation structures 207. In two adjacent isolation structures 207, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers, thereby forming an undercut structure.

[0078] For example, in other examples, the isolation structure 207 may also include two stacked structures, namely a first stacked structure and a second stacked structure, wherein the first stacked structure is closer to the substrate 201 than the second stacked structure, the maximum distance between adjacent first stacked structures is greater than the maximum distance between adjacent second stacked structures, and the minimum distance between adjacent first stacked structures is greater than the minimum distance between adjacent second stacked structures, thereby forming an undercut structure.

[0079] For example, in one example, the first titanium metal layer is closer to the substrate 201 than the second titanium metal layer, and there are multiple isolation structures 207. In two adjacent isolation structures 207, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers, thereby further forming an undercut structure.

[0080] For example, in one example, the material of the protective layer 213 is at least one of silicon nitride, silicon oxide, and silicon oxynitride. For example, the protective layer 213 can be fabricated using appropriate processes with equipment such as low-temperature plasma-enhanced chemical vapor deposition, atomic layer deposition, and sputtering.

[0081] For example, in one example, the thickness of the protective layer 213 ranges from 3000 Å to 15000 Å.

[0082] For example, Figure 3 is a cross-sectional structural diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in Figure 3, the inorganic material layer 214 is the first inorganic encapsulation layer 214a. Based on the display substrate shown in Figure 2, the display substrate 200 further includes an organic encapsulation layer 215 and a second inorganic encapsulation layer 216 stacked on the first inorganic encapsulation layer 214a. The first inorganic encapsulation layer 214a, the organic encapsulation layer 215, and the second inorganic encapsulation layer 216 constitute an encapsulation structure, and an auxiliary layer 208 is disposed between the first inorganic encapsulation layer 214a and the organic encapsulation layer 215. It can be seen from Figure 3 that the organic encapsulation layer 215 has high flow uniformity.

[0083] For example, Figure 4 is a cross-sectional structural schematic diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in Figure 4, the display substrate 200 includes a substrate 201 and a pixel defining layer 202 located on the substrate 201. The pixel defining layer 202 includes a plurality of pixel openings 203 and pixel spacing portions 204 that space the plurality of pixel openings 203. A plurality of sub-pixels 205 are provided on the substrate 201. The plurality of sub-pixels 205 correspond one-to-one with the plurality of pixel openings 203. Each sub-pixel 205 includes a light-emitting element 206. An isolation structure 207 is provided on the surface of the spacer 204 away from the substrate 201. An inorganic material layer 214 is provided on the surface of the isolation structure 207 away from the substrate 201. The inorganic material layer 214 is a first inorganic encapsulation layer 214a. An auxiliary layer 208 is provided on the surface of the first inorganic encapsulation layer 214a away from the substrate 201. The auxiliary layer 208 can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the final light-emitting diode display panel.

[0084] For example, the isolation structure 207 and the auxiliary layer 208 are disposed in the display area of ​​the display substrate to, for example, block the lateral crosstalk of electrons in the charge generation layer of the light-emitting diode display device, thereby making the organic encapsulation layer of the final display substrate more uniformly leveled during the formation process.

[0085] For example, as shown in Figure 4, the auxiliary layer 208 is made of a metal oxide with strong hydrophilicity. Since hydrophobic structures are easily formed at the slits between adjacent protective layers 213, the entire layer of the strongly hydrophilic metal oxide can fill the pixel opening 203, thereby reducing the hydrophobic properties between adjacent isolation structures 207, and thus improving the leveling properties of the subsequently formed organic encapsulation layer.

[0086] For example, in one example, the material of the auxiliary layer 208 is titanium dioxide, which is nano-titanium dioxide. For example, strong hydrophilic titanium dioxide can be deposited by atomic layer deposition or direct deposition to form the auxiliary layer. That is, by adding the auxiliary layer 208 as a flow-guiding functional layer of the encapsulated organic encapsulation layer, the uniformity of the flow level of the encapsulated organic encapsulation layer can be improved.

[0087] For example, Figure 5A is a cross-sectional structural schematic diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in Figure 5A, based on the display substrate shown in Figure 4, the display substrate 200 further includes an organic encapsulation layer 215 and a second inorganic encapsulation layer 216 stacked on the first inorganic encapsulation layer 214a. The first inorganic encapsulation layer 214a, the organic encapsulation layer 215 and the second inorganic encapsulation layer 216 constitute an encapsulation structure, and an auxiliary layer 208 is disposed between the first inorganic encapsulation layer 214a and the organic encapsulation layer 215. It can be seen from Figure 5A that the organic encapsulation layer 215 has high flow uniformity.

[0088] For example, in the structure shown in Figure 5A, the auxiliary layer 208 is very thin. While it plays a role in enhancing the uniformity of the flow of the organic encapsulation layer during the flow leveling process, it does not significantly increase the thickness of the entire encapsulation structure. Therefore, it does not affect the thickness of the entire display substrate.

[0089] For example, in the structure of the display substrate shown in Figures 2 to 5A, the plurality of sub-pixels 205 constitute a plurality of pixel units, each pixel unit including a first color sub-pixel 2051, a second color sub-pixel 2052 and a third color sub-pixel 2053 arranged in the first direction X.

[0090] For example, in one example, the first color subpixel 2051 is a red subpixel, the second color subpixel 2052 is a green subpixel, and the third color subpixel 2053 is a blue subpixel.

[0091] For example, in the structure of the display substrate shown in Figures 2 to 5A, a first stacked portion of a first color light-emitting functional layer residual structure 218 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the first color sub-pixel 2051 near the first color sub-pixel 2051; a second stacked portion of a second color light-emitting functional layer residual structure 219 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the second color sub-pixel 2052 near the second color sub-pixel 2052; and a third stacked portion of a third color light-emitting functional layer residual structure 220 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the third color sub-pixel 2053 near the third color sub-pixel 2053.

[0092] For example, in one example, a planarization layer can also be provided between the light-emitting element 206 and the auxiliary layer 208. This planarization layer can play a planarization role, so that the structure above the light-emitting element 206 is flatter.

[0093] For example, Figure 5B is a cross-sectional structural diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in Figure 5B, the inorganic material layer 214 is a protective layer 213. The protective layer 213 is in direct contact with the auxiliary layer 208. That is, the difference between Figure 5B and Figure 5A is that the first inorganic encapsulation layer is reduced in the structure shown in Figure 5B, and the protective layer 213 can play the role of the first inorganic encapsulation layer.

[0094] For example, as shown in FIG5B, the display substrate 200 further includes an organic encapsulation layer 215 and a second inorganic encapsulation layer 216 stacked on the protective layer 213. The protective layer 213, the organic encapsulation layer 215 and the second inorganic encapsulation layer 216 constitute an encapsulation structure, and an auxiliary layer 208 is disposed between the protective layer 213 and the organic encapsulation layer 215. It can be seen from FIG5B that the organic encapsulation layer 215 has high flow uniformity.

[0095] For example, in the structure shown in Figure 5B, the auxiliary layer 208 is very thin. While it plays a role in enhancing the uniformity of the flow of the organic encapsulation layer during the flow process, it does not significantly increase the thickness of the entire encapsulation structure. Therefore, it does not affect the thickness of the entire display substrate.

[0096] For example, in the structure of the display substrate shown in 5B, the plurality of sub-pixels 205 constitute a plurality of pixel units, each pixel unit including a first color sub-pixel 2051, a second color sub-pixel 2052 and a third color sub-pixel 2053 arranged in the first direction X.

[0097] For example, in one example, the first color subpixel 2051 is a red subpixel, the second color subpixel 2052 is a green subpixel, and the third color subpixel 2053 is a blue subpixel.

[0098] For example, in the structure of the display substrate shown in FIG5B, a first stacked portion of a first color light-emitting functional layer residual structure 218 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the first color sub-pixel 2051 near the first color sub-pixel 2051; a second stacked portion of a second color light-emitting functional layer residual structure 219 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the second color sub-pixel 2052 near the second color sub-pixel 2052; and a third stacked portion of a third color light-emitting functional layer residual structure 220 and a cathode residual structure 217 is provided at the end of the pixel spacing portion 204 adjacent to the third color sub-pixel 2053 near the third color sub-pixel 2053.

[0099] For example, in one example, a planarization layer can also be provided between the light-emitting element 206 and the auxiliary layer 208. This planarization layer can play a planarization role, so that the structure above the light-emitting element 206 is flatter.

[0100] For example, in one example, the material of the protective layer 213 is at least one of silicon nitride, silicon oxide, and silicon oxynitride. For example, the protective layer 213 can be fabricated using appropriate processes with equipment such as low-temperature plasma-enhanced chemical vapor deposition, atomic layer deposition, and sputtering.

[0101] For example, in one example, the thickness of the protective layer 213 ranges from 3000 Å to 15000 Å.

[0102] At least one embodiment of this disclosure also provides a method for fabricating a display substrate. The method includes: providing a substrate; forming a pixel defining layer on the substrate, wherein the pixel defining layer includes a plurality of pixel openings and pixel spacing portions that space the plurality of pixel openings; forming a plurality of sub-pixels in the plurality of pixel openings, wherein the plurality of sub-pixels correspond one-to-one with the plurality of pixel openings, and each sub-pixel includes a light-emitting element; forming an isolation structure on the surface of the pixel spacing portions away from the substrate; forming an inorganic material layer on the side of the isolation structure away from the substrate; and forming an auxiliary layer on the side of the inorganic material layer away from the substrate. For example, during the fabrication of the display substrate using this method, the auxiliary layer can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the finally formed light-emitting diode display panel.

[0103] For example, Figure 6 is a flowchart of a method for preparing a display substrate according to at least one embodiment of the present disclosure. As shown in Figure 6, the preparation method includes the following steps.

[0104] Step S101: Provide a substrate.

[0105] For example, the substrate can be a glass substrate, a quartz substrate, or a flexible display substrate, etc., and the embodiments disclosed herein are not limited to this.

[0106] Step S102: A pixel defining layer is formed on a substrate, wherein the pixel defining layer includes a plurality of pixel openings and pixel spacing portions that space the plurality of pixel openings.

[0107] For example, the pixel defining layer can be made of an inorganic insulating material, and the pixel defining layer can be formed using a photolithography method.

[0108] Step S103: Multiple sub-pixels are formed in multiple pixel openings, and the multiple sub-pixels correspond one-to-one with the multiple pixel openings. Each sub-pixel includes a light-emitting element.

[0109] For example, multiple sub-pixels form multiple pixel units, and each pixel unit corresponds to a first color opening region, a second color opening region, and a third color opening region that are sequentially adjacent.

[0110] Step S104: An isolation structure is formed on the surface of the pixel spacing away from the substrate.

[0111] For example, the isolation structure can be a stacked structure formed by sequentially stacking a first titanium metal layer Ti, an aluminum metal layer Al, and a second titanium metal layer Ti. The isolation structure can be multiple stacked structures.

[0112] Step S105: An inorganic material layer is formed on the side of the isolation structure away from the substrate.

[0113] For example, the inorganic material layer can be made of silicon oxide or silicon oxynitride, etc.

[0114] Step S106: An auxiliary layer is formed on the side of the inorganic material layer away from the substrate.

[0115] For example, the auxiliary layer can be made of a highly hydrophilic metal oxide. Since a hydrophobic structure is formed at the location corresponding to the pixel opening, the highly hydrophilic metal oxide can reduce the hydrophobic properties at at least some locations between adjacent isolation structures, thereby improving the leveling properties of the subsequently formed organic encapsulation layer.

[0116] For example, in one example, the material of the auxiliary layer is titanium dioxide, which is nano-titanium dioxide. For example, highly hydrophilic titanium dioxide can be deposited by atomic layer deposition or direct deposition to form the auxiliary layer. That is, by adding the auxiliary layer as a flow-guiding functional layer of the organic encapsulation layer, the uniformity of the flow level of the organic encapsulation layer can be improved.

[0117] For example, during the process of forming a display substrate using this preparation method, the auxiliary layer can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the final light-emitting diode display panel.

[0118] For example, when the auxiliary layer is formed using titanium dioxide, due to the high refractive index of titanium dioxide and the refractive index n of the organic encapsulation layer being approximately 1.53, there is a refractive index difference between the auxiliary layer and the organic encapsulation layer. Therefore, it is necessary to form an antireflection structure with subsequent multi-layer films. For example, in one example of this disclosure, the inorganic material layer is the first inorganic encapsulation layer. The refractive index of the first inorganic encapsulation layer needs to be set to 1.75, the refractive index of the auxiliary layer needs to be set to 2, and the refractive index of the organic encapsulation layer needs to be set to 1.53, thereby improving the front light emission efficiency of the final OLED device.

[0119] For example, in the fabrication method provided in at least one embodiment of this disclosure, forming a light-emitting element includes: sequentially forming a light-emitting functional layer and a cathode layer on the side of the pixel opening away from the substrate; forming a photoresist layer on the cathode layer; and performing a patterning process on the photoresist layer to form a photoresist retention area and a photoresist removal area, wherein the photoresist retention area is the area where a light-emitting element of the corresponding color is formed, that is, the various layer structures of the light-emitting element are formed by photolithography.

[0120] At least one embodiment of this disclosure also provides another display substrate, the display substrate comprising: a substrate; a pixel defining layer located on the substrate, the pixel defining layer including a plurality of pixel openings and pixel spacing portions spaced apart from the plurality of pixel openings; a plurality of sub-pixels on the substrate, the plurality of sub-pixels corresponding one-to-one with the plurality of pixel openings, each sub-pixel including a light-emitting element; a first isolation portion disposed at both ends of the pixel defining layer; a first planarization layer disposed between the light-emitting element and the substrate, the end of the first isolation portion away from the pixel opening being further away from the pixel opening than the corresponding end of the first planarization layer away from the pixel opening, and the end of the first isolation portion away from the pixel opening and the corresponding end of the first planarization layer away from the pixel opening being stacked to form an isolation structure, and an auxiliary layer disposed on the side surface of the isolation structure.

[0121] For example, in automotive-grade tandem devices, tandem luminescent materials are used to reduce the power consumption of the display substrate and achieve high brightness. Due to the high brightness of tandem devices, they are widely used in automotive and other products with stringent requirements for display substrate lifespan and brightness.

[0122] For example, compared to the light-emitting materials in a single-layer display substrate, tandem light-emitting materials have an additional layer of light-emitting material and an extra charge-generating layer, which has strong conductivity. To prevent lateral crosstalk between the charge-generating layers of adjacent sub-pixels as the resolution of the display panel increases, isolation structures are set between adjacent sub-pixels to disconnect the charge-generating layers without affecting the normal illumination of the pixels. There are various types of isolation structures, such as T-shaped isolation pillars formed by passivation and planarization layers, inverted trapezoidal isolation pillars formed by negative photoresist, or other isolation pillar structures.

[0123] For example, Figure 7 is a schematic cross-sectional structure of a display substrate. As shown in Figure 7, the display substrate 300 includes a substrate 301, a buffer layer 302 disposed on the substrate 301, a semiconductor layer 311 disposed on the buffer layer 302, a first gate insulating layer 314 disposed on the semiconductor layer 311, a gate electrode 312 disposed on the first gate insulating layer 314, a second gate insulating layer 315 disposed on the gate electrode 312, an interlayer insulating layer 316 disposed on the second gate insulating layer 315, and a first source / drain electrode 313 and a second source / drain electrode 318 disposed on the interlayer insulating layer 316. The semiconductor layer 311 and the first gate insulating layer... 314, a second gate insulating layer 315, an interlayer insulating layer 316, a first source / drain electrode 313, and a second source / drain electrode 318 constitute a thin-film transistor 320. A light-emitting element is disposed on the thin-film transistor 320. The light-emitting element includes a first electrode 304 connected to a transition electrode 317. The transition electrode 317 is electrically connected to the first source / drain electrode 313 through a via structure disposed in the first planarization layer 307 and the first passivation layer 306. A second planarization layer 308 is disposed between the transition electrode 317 and the first electrode 304. The first electrode 304 is electrically connected to the transition electrode 317 through a via structure disposed in the second planarization layer 308. The light-emitting element is disposed on the second planarization layer 308. A pixel defining layer 309 and a second passivation layer 310 are disposed on the second planarization layer 308. The pixel defining layer 309 includes a pixel opening 3091 and a pixel spacing portion 3092. A light-emitting functional layer is disposed on the first electrode 304 in the pixel opening 3091. In the structure shown in Figure 7, the second planarization layer 308 and the second passivation layer 310 form a T-shaped isolation structure at the edge. Since the isolation structure is fabricated as a single layer, there is also a risk of poor leveling of the encapsulation organic layer film during the subsequent formation of the encapsulation organic layer. This is especially true in automotive active privacy products, where multiple shielding layers are introduced, and the thickness of the encapsulation organic layer included in the encapsulation structure needs to be as thin as possible, thus exacerbating the risk of poor leveling.

[0124] For example, Figure 8 is a schematic diagram of a cross-sectional structure of another display substrate. The difference between Figure 8 and Figure 7 is that in the structure shown in Figure 8, a light-emitting functional layer and a combination 320 of the second electrode are formed on the first electrode 304. A first inorganic encapsulation layer 319 is formed on the combination 320 of the light-emitting functional layer and the second electrode. As can be seen from Figure 8, the first inorganic encapsulation layer 319 is formed on the substrate 301. Since the second planarization layer 308 and the second passivation layer 310 form a T-shaped isolation structure at the edge, the first inorganic encapsulation layer 319 also has a bent structure at the edge of the substrate 301. This makes it easy for the organic encapsulation layer formed later to have uneven leveling at the edge.

[0125] For example, FIG9 is a cross-sectional structural schematic diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in FIG9, the display substrate 400 includes: a substrate 401; a pixel defining layer 402 located on the substrate 401, the pixel defining layer 402 including a plurality of pixel openings 403 and pixel spacing portions 404 spacing the plurality of pixel openings 403; a plurality of sub-pixels 405 on the substrate 401, the plurality of sub-pixels 405 corresponding one-to-one with the plurality of pixel openings 403, each sub-pixel 405 including a light-emitting element 406; and a pixel defining layer 402 including a pixel opening 403. A first isolation portion 407 is provided at both ends of component 2; a first planarization layer 408 is provided between the light-emitting element 406 and the substrate 401. The end of the first isolation portion 407 that is farther from the pixel opening 403 is farther from the corresponding end of the first planarization layer 408 that is farther from the pixel opening 403. The end of the first isolation portion 407 that is farther from the pixel opening 403 and the corresponding end of the first planarization layer 408 that is farther from the pixel opening 403 are stacked to form an isolation structure 409. An auxiliary layer 410 is provided on the side surface of the isolation structure 409. For example, the auxiliary layer 410 can help the leveling of the organic encapsulation film when the organic encapsulation layer is subsequently formed, thereby improving the flatness of the subsequently formed organic encapsulation layer.

[0126] For example, as shown in FIG9, the display substrate 400 further includes a buffer layer 426 disposed on the substrate 401, a semiconductor layer 411 disposed on the buffer layer 426, a first gate insulating layer 414 disposed on the semiconductor layer 411, a gate electrode 412 disposed on the first gate insulating layer 414, a second gate insulating layer 415 disposed on the gate electrode 412, an interlayer insulating layer 416 disposed on the second gate insulating layer 415, and a first source / drain electrode 413 and a second source / drain electrode 418 disposed on the interlayer insulating layer 416. The semiconductor layer 411, the first gate insulating layer 414, the second gate insulating layer 415, the interlayer insulating layer 416, and the first source / drain electrode 413 are all present. A thin-film transistor 420 is formed by a second source / drain electrode 418. A light-emitting element is disposed on the thin-film transistor 420. The light-emitting element includes a first electrode 424 and a transition electrode 423 connected together. The transition electrode 423 is electrically connected to the first source / drain electrode 418 through a via structure disposed in the second planarization layer 421 and the first passivation layer 419. A first planarization layer 422 is disposed between the transition electrode 423 and the first electrode 424. The first electrode 424 is electrically connected to the transition electrode 423 through a via structure disposed in the first planarization layer 422. The light-emitting element is disposed on the first planarization layer 422. A pixel defining layer 402 and a second passivation layer 427 are disposed on the first planarization layer 422. The edge of the second passivation layer 427 serves as a first isolation portion 407. The pixel defining layer 402 includes a pixel opening 403 and a pixel spacing portion 404. A light-emitting functional layer is disposed on the first electrode 424 in the pixel opening 403.

[0127] For example, in the structure shown in Figure 9, the first planarization layer 422 and the second passivation layer 427 form a T-shaped isolation structure at the edge. An auxiliary layer 410 is provided on the side surface of the isolation structure 409. For example, this auxiliary layer 410 can help with the leveling of the organic encapsulation film during the subsequent formation of the organic encapsulation layer, thereby improving the flatness of the subsequently formed organic encapsulation layer.

[0128] For example, as shown in FIG9, the display substrate 400 further includes a first inorganic encapsulation layer 425 disposed on the side of the light-emitting element 406 away from the substrate 401. The first inorganic encapsulation layer 425 covers the edge of the T-shaped isolation structure, that is, the auxiliary layer 410 is disposed at the position where the first inorganic encapsulation layer 425 covers the T-shaped isolation structure. The display substrate 400 includes an encapsulation structure, which includes the aforementioned first inorganic encapsulation layer 425, an encapsulation organic layer, and a second inorganic encapsulation layer, with the auxiliary layer 410 disposed between the first inorganic encapsulation layer 425 and the encapsulation organic layer.

[0129] For example, as shown in Figure 9, the material of the auxiliary layer 410 includes light-absorbing organic materials or metal oxides. For instance, the material of the auxiliary layer 410 can be a material used to fabricate optical adhesives or black matrices, and the polarity of the material of the auxiliary layer 410 is similar to the polarity of the encapsulation organic layer in the encapsulation structure. The material of the auxiliary layer 410 can also include materials with low reflectivity.

[0130] For example, when the material of the auxiliary layer 410 is a metal oxide with light-absorbing properties, the light-absorbing metal oxide includes at least one of molybdenum tantalum oxide, copper oxide, molybdenum oxide, and zinc oxide. For example, the auxiliary layer 410 can be formed by chemical deposition or other methods.

[0131] For example, as shown in FIG9, the light-emitting element 406 includes a second electrode, which is a cathode. The cathode includes a portion disposed on the isolation structure 409, and the cathode is disconnected at a position corresponding to the isolation structure 409. The isolation structure 409 has an undercut structure, thereby allowing the structure formed thereon to automatically disconnect at the position corresponding to the isolation structure 409.

[0132] For example, the first electrode 424 is the anode of the light-emitting element 406. The anode is electrically connected to the transition electrode 423 through a first via structure 428 disposed in the first planarization layer 422. The transition electrode 423 is electrically connected to the first source / drain electrode 418 of the thin-film transistor through a second via structure 429 disposed in the second planarization layer 421 and the first passivation layer 419.

[0133] For example, the cathode can be formed of a material with high conductivity and low work function. For example, the cathode can be made of a metallic material. For example, the anode can be formed of a transparent conductive material with a high work function.

[0134] For example, as shown in Figure 9, the materials of the first planarization layer 408 and the second planarization layer 421 can be organic materials, such as resin, acrylic or polyethylene terephthalate, polyimide, polyamide, polycarbonate, epoxy resin, etc., or a combination of several of them.

[0135] For example, in one example, the thickness of both the first planarization layer 408 and the second planarization layer 421 can be 1 micrometer to 3 micrometers. In another example, the thickness of both the first planarization layer 408 and the second planarization layer 421 can be 1.5 micrometers to 2 micrometers.

[0136] For example, in some examples, other film layers are disposed between the first planarization layer 408 and the substrate 401. These other film layers may include various film layers in the pixel driving circuit (e.g., including thin film transistors, storage capacitors, etc.), data lines, gate lines, power signal lines, reset power signal lines, reset control signal lines, light emission control signal lines, etc.

[0137] For example, Figure 10 is a cross-sectional structural schematic diagram of another display substrate provided in at least one embodiment of the present disclosure. As shown in Figure 10, an organic encapsulation layer 431 and a second inorganic encapsulation layer 432 are provided on the first inorganic encapsulation layer 425 and the auxiliary layer 410. The first inorganic encapsulation layer 425, the organic encapsulation layer 431 and the second inorganic encapsulation layer 432 constitute an encapsulation structure. This encapsulation structure can prevent external moisture and oxygen from affecting the light-emitting element.

[0138] For example, by taking advantage of the fact that the polarity of the auxiliary layer is similar to that of the organic encapsulation layer, the organic encapsulation material is guided to the edge of the pit formed by the isolation structure, making it easier for the organic encapsulation material to fill the pit. This allows the organic encapsulation layer to achieve the requirements of planarization and low thickness.

[0139] For example, since the auxiliary layer mainly adheres to the sides and bottom of the partition structure after etching, the auxiliary layer can simultaneously play the role of stress relief and slit filling, which is conducive to the stability of the partition structure and thus can improve the reliability of the display substrate.

[0140] For example, Figures 11 and 12 are diagrams of the preparation process of the auxiliary layer in the display substrate shown in Figure 9. As shown in Figure 11, an auxiliary layer film 410' is formed on a substrate 401 on which a first inorganic encapsulation layer 425 and other structures are formed. The auxiliary layer film 410' covers the entire surface of the first inorganic encapsulation layer 425.

[0141] For example, as shown in Figure 12, utilizing the undercut structure of the isolation structure itself, the auxiliary layer film 410' can be directly etched using methods such as dry etching to form the auxiliary layer 410. That is, the auxiliary layer film 410' is directly broken at the corresponding position of the isolation structure, and the auxiliary layer film 410' on the upper side of the first inorganic encapsulation layer is peeled off, leaving the auxiliary layer film 410' on the left side of the first inorganic encapsulation layer to form the auxiliary layer. For example, the pixel driving circuit 206 is configured to drive the light-emitting element 106 to emit light. The light-emitting functional layer 1063 may include multiple sub-functional layers, which may include charge generation layers with high conductivity. It should be noted that the aforementioned light-emitting functional layer does not only include the film layer that directly emits light, but also includes functional film layers used to assist in light emission, such as: hole injection layer, hole transport layer, electron injection layer, electron transport layer, electron blocking layer, and hole blocking layer, etc.

[0142] At least one embodiment of this disclosure also provides a display device. FIG13 is a schematic diagram of a display device provided in at least one embodiment of this disclosure. As shown in FIG13, the display device 500 includes a display substrate 400. The display substrate of the display device avoids crosstalk between adjacent sub-pixels caused by the highly conductive charge generation layer by providing a partition structure between adjacent sub-pixels and causing the charge generation layer in the light-emitting functional layer to be disconnected at the location of the partition structure. The display substrate of the display device has an auxiliary layer provided on the surface of the isolation structure away from the substrate. The auxiliary layer can improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thereby improving the structural stability of the finally formed light-emitting diode display panel. Thus, the display device including this display substrate can also avoid crosstalk between adjacent sub-pixels and improve the uniformity of the flow of the organic encapsulation film when forming the organic encapsulation layer, thus having a higher product yield and higher display quality.

[0143] On the other hand, since the display substrate can employ a dual-layer tandem EL design while simultaneously providing an auxiliary layer on the side surface of the isolation structure, this auxiliary layer can improve the uniformity of the organic encapsulation film during the formation of the organic encapsulation layer. This allows the final encapsulation structure to prevent external water and oxygen from entering the light-emitting element, thereby improving the lifespan of the display substrate. Therefore, when an auxiliary layer is provided on the side surface of the isolation structure included in the display substrate, the display device including this display substrate has advantages such as long lifespan, low power consumption, high brightness, and high resolution.

[0144] For example, the display device can be an organic light-emitting diode display device or other display device, as well as any product or component with display function, such as a television, digital camera, mobile phone, watch, tablet computer, laptop computer, or navigator that includes the display device. This embodiment is not limited to this.

[0145] The following points need to be explained:

[0146] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0147] (2) For clarity, the thickness of layers or regions in the drawings used to describe embodiments of the present disclosure is enlarged or reduced, i.e., these drawings are not drawn to actual scale.

[0148] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0149] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. The scope of protection of this disclosure should be determined by the scope of protection of the claims.

Claims

1. A display substrate, comprising: Substrate; A pixel defining layer, located on the substrate, includes a plurality of pixel openings and pixel spacing portions that space the plurality of pixel openings; Multiple sub-pixels are located on the substrate and correspond one-to-one with the multiple pixel openings. Each sub-pixel includes a light-emitting element. An isolation structure is located on the surface of the pixel spacing portion that is away from the substrate. An inorganic material layer is located on the side of the isolation structure away from the substrate, wherein an auxiliary layer is provided on the surface of the inorganic material layer away from the substrate.

2. The display substrate according to claim 1, wherein, The auxiliary layer is made of a metal oxide with strong hydrophilicity.

3. The display substrate according to claim 2, wherein, The auxiliary layer is made of titanium dioxide.

4. The display substrate according to any one of claims 1 to 3, wherein, The auxiliary layer may include multiple spaced-apart sub-auxiliary structures, or the auxiliary layer may be a single integral structure.

5. The display substrate according to claim 4, wherein, The isolation structure comprises a stacked structure formed by sequentially stacking at least one first titanium metal layer, an aluminum metal layer, and a second titanium metal layer.

6. The display substrate according to claim 5, wherein, The isolation structure includes one of the stacked structures, wherein the first titanium metal layer is closer to the substrate than the second titanium metal layer, and there are multiple isolation structures. In two adjacent isolation structures, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers.

7. The display substrate according to claim 5, wherein, The isolation structure includes two stacked structures, which are a first stacked structure and a second stacked structure. The first stacked structure is closer to the substrate than the second stacked structure. The maximum distance between adjacent first stacked structures is greater than the maximum distance between adjacent second stacked structures, and the minimum distance between adjacent first stacked structures is greater than the minimum distance between adjacent second stacked structures.

8. The display substrate according to claim 7, wherein, In each of the stacked structures, the first titanium metal layer is closer to the substrate than the second titanium metal layer. There are multiple isolation structures. In two adjacent isolation structures, the spacing between adjacent aluminum metal layers is greater than the spacing between adjacent second titanium metal layers, and the spacing between adjacent second titanium metal layers is greater than the spacing between adjacent first titanium metal layers.

9. The display substrate according to any one of claims 1 to 8, wherein, The inorganic material layer is a first inorganic encapsulation layer. The display substrate further includes an organic encapsulation layer and a second inorganic encapsulation layer stacked on the first inorganic encapsulation layer. The first inorganic encapsulation layer, the organic encapsulation layer, and the second inorganic encapsulation layer constitute an encapsulation structure, and the auxiliary layer is disposed between the first inorganic encapsulation layer and the organic encapsulation layer.

10. The display substrate according to any one of claims 1 to 8, wherein, The inorganic material layer is a protective layer, and the protective layer and the auxiliary layer are in direct contact.

11. The display substrate according to any one of claims 1 to 10, wherein, The plurality of sub-pixels constitute a plurality of pixel units, and each pixel unit includes a first color sub-pixel, a second color sub-pixel, and a third color sub-pixel arranged in a first direction.

12. The display substrate according to claim 11, wherein, The first color sub-pixel is a red sub-pixel, the second color sub-pixel is a green sub-pixel, and the third color sub-pixel is a blue sub-pixel.

13. The display substrate according to claim 11, wherein, A first stacked portion of a first color emitting functional layer residual structure and a cathode residual structure is provided at the end of the pixel interval adjacent to the first color sub-pixel near the first color sub-pixel; A second stacked portion of the second color emitting functional layer residual structure and the cathode residual structure is provided at the end of the pixel interval adjacent to the second color sub-pixel near the second color sub-pixel; A third stacked portion of the third color emitting functional layer residual structure and the cathode residual structure is provided at the end of the pixel interval adjacent to the third color sub-pixel.

14. The display substrate according to claim 13, wherein, A planarization layer is also provided between the light-emitting element and the auxiliary layer.

15. A method for preparing a display substrate, comprising: Provide substrates; A pixel defining layer is formed on the substrate, wherein the pixel defining layer includes a plurality of pixel openings and pixel spacing portions that space the plurality of pixel openings; Multiple sub-pixels are formed in the plurality of pixel openings, wherein each of the plurality of sub-pixels corresponds one-to-one with the plurality of pixel openings, and each of the sub-pixels includes a light-emitting element; An isolation structure is formed on the surface of the pixel spacing portion away from the substrate. An inorganic material layer is formed on the side of the isolation structure away from the substrate. An auxiliary layer is formed on the side of the inorganic material layer away from the substrate.

16. The preparation method according to claim 15, wherein, The light-emitting element comprises: A light-emitting functional layer and a cathode layer are sequentially formed on the side of the pixel opening away from the substrate. A photoresist layer is formed on the cathode layer; The photoresist layer is patterned to form a photoresist retention area and a photoresist removal area, wherein the photoresist retention area corresponds to the area where the light-emitting element of the corresponding color is formed.

17. A display substrate, comprising: Substrate; A pixel defining layer, located on the substrate, includes a plurality of pixel openings and pixel spacing portions that space the plurality of pixel openings; Multiple sub-pixels are located on the substrate and correspond one-to-one with the multiple pixel openings. Each sub-pixel includes a light-emitting element. A first isolation portion is provided at both ends of the pixel defining layer; A first planarization layer is provided between the light-emitting element and the substrate, wherein the end of the first isolation portion away from the pixel opening is further away from the pixel opening than the corresponding end of the first planarization layer away from the pixel opening, and the end of the first isolation portion away from the pixel opening and the corresponding end of the first planarization layer away from the pixel opening are stacked to form an isolation structure, and an auxiliary layer is provided on the side surface of the isolation structure.

18. The display substrate according to claim 17, further comprising an encapsulation structure disposed on the side of the light-emitting element away from the substrate, wherein, The encapsulation structure includes a first inorganic encapsulation layer, an organic encapsulation layer, and a second inorganic encapsulation layer stacked together, with the auxiliary layer disposed between the first inorganic encapsulation layer and the organic encapsulation layer.

19. The display substrate according to claim 17 or 18, wherein, The auxiliary layer is made of light-absorbing organic materials or metal oxides.

20. The display substrate according to claim 19, wherein, The light-absorbing metal oxide includes at least one of molybdenum tantalum oxide, copper oxide, molybdenum oxide, and zinc oxide.

21. The display substrate according to any one of claims 17 to 20, wherein, The light-emitting element includes a second electrode, which includes a portion disposed on the isolation structure, and the second electrode is disconnected at a position corresponding to the isolation structure.

22. The display substrate according to claim 21, further comprising a thin-film transistor disposed between the substrate and the light-emitting element, wherein, The first electrode of the light-emitting element is electrically connected to a transition electrode through a first via structure disposed in the first planarization layer, and the transition electrode is electrically connected to the first source / drain electrode of the thin-film transistor through a second via structure disposed in the second planarization layer and the first passivation layer.

23. A display device comprising a display substrate according to any one of claims 1 to 14, or a display substrate according to any one of claims 17 to 22.

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