Display substrate and preparation method thereof

Abstract

The invention provides a display substrate and a preparation method thereof, belongs to the technical field of display, and can solve the problem that the sight of a driver is affected by emergent light, close to a windshield, of an existing display substrate applied to an automobile central control screen. The display substrate comprises a substrate body, a plurality of light-emitting devices and a pixel defining layer. The light-emitting device comprises a first electrode, a light-emitting layer and a second electrode. The pixel defining layer is provided with a plurality of pixel openings; the orthographic projection of one first electrode and the orthographic projection of one pixel opening on the substrate at least partially coincide; the display substrate is provided with a first side and a second side; the distance between at least part of the position, away from the surface of the substrate, of the part, located in the pixel opening, of the first electrode and the substrate is not equal, and the distance between the position close to the first side and the substrate is not smaller than the distance between the position close to the second side and the substrate. The display substrate disclosed by the invention can effectively reduce the light projected to the windshield side and reduce the interference of the projection phenomenon on a driver.

Description

Technical Field

[0001] The present disclosure belongs to the field of display technology, and particularly relates to a display substrate and a preparation method thereof. Background Art

[0002] With the rapid development of new energy vehicle technology, large central control screens or instrument panels are increasingly favored by electric vehicle manufacturers; however, at the same time, large central control screens or instrument panels also have some safety hazards. For example, when the light emitted by the central control screen, electronic instrument panel, or co-pilot screen is reflected on the front windshield, a projection phenomenon will be formed, which will interfere with the driver's vision and affect the driver's normal driving.

[0003] Therefore, a display screen is needed which does not affect the front display effect but does not project light onto the front windshield as much as possible. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. On the one hand, a display substrate is provided, which includes a base substrate, a plurality of light-emitting devices arranged on the base substrate, and a pixel defining layer; the light-emitting device includes a first electrode, a light-emitting layer, and a second electrode stacked in sequence in a direction away from the base substrate; the pixel defining layer is arranged on a side of the first electrode away from the base substrate, and has a plurality of pixel openings penetrating along its thickness direction; the orthographic projections of one first electrode and one pixel opening on the base substrate at least partially overlap; wherein the display substrate has a first side and a second side arranged oppositely; for a portion of the first electrode located in the pixel opening, the distance between at least a portion of its surface away from the base substrate and the base substrate is unequal, and the distance between a position close to the first side and the base substrate is not less than the distance between a portion close to the second side and the base substrate.

[0005] In some examples, a planarization layer is further included and arranged between the base substrate and the first electrode; the planarization layer includes a flat portion and a plurality of protrusions, and the protrusions are located on the side of the flat portion facing away from the base substrate; one of the protrusions at least partially overlaps with the positive projection of one of the pixel openings on the base substrate, one of the first electrodes is located on the side of one of the protrusions facing away from the base substrate, and in the direction from the first side to the second side, the distance between the protrusion and the flat portion decreases monotonically.

[0006] In some examples, the protrusion includes a first bottom surface and a first side surface; the intersection of the first bottom surface and the first side surface is a first intersection line, and the tangent plane of the first side surface passing through any point on the first intersection line is called a first tangent plane; the angle between the first tangent plane and the first bottom surface is greater than 0° and less than or equal to 30°.

[0007] In some examples, the first side surface includes at least one of a planar surface, a convex surface, or a concave surface.

[0008] In some examples, the protrusion includes a plurality of sub-protrusions stacked in a direction away from the substrate base.

[0009] In some examples, the first black matrix layer and the second black matrix layer are sequentially arranged on the side of the light-emitting device away from the base substrate; the first black matrix layer is provided with a plurality of first light-transmitting portions corresponding one-to-one to the pixel openings; the second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one-to-one to the pixel openings; and the minimum distance between the first light-transmitting portion and the first side is smaller than the minimum distance between the second light-transmitting portion and the first side.

[0010] In some examples, a minimum distance between the first light-transmitting portion and the second side is not less than a minimum distance between the second light-transmitting portion and the second side.

[0011] In some examples, in a direction from the first side to the second side, a length ratio of the second light-transmitting portion to the first light-transmitting portion is 0.9:1 to 1.5:1.

[0012] In some examples, the first black matrix layer and the second black matrix layer are sequentially arranged on the side of the light-emitting device away from the base substrate; the first black matrix layer is provided with a plurality of first light-transmitting portions corresponding one-to-one to the pixel openings; the orthographic projection of the first light-transmitting portion on the base substrate is located in the corresponding pixel opening; the second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one-to-one to the pixel openings; the orthographic projection of the first edge of the second light-transmitting portion on the base substrate overlaps with the orthographic projection of the first light-transmitting portion on the base substrate; the distance between the first edge of the second light-transmitting portion and the first side is not greater than the distance between the other parts of the second light-transmitting portion and the first side.

[0013] In some examples, the orthographic projection of the second edge of the second light-transmitting portion on the base substrate and the orthographic projection of the first light-transmitting portion on the base substrate do not overlap; and the spacing between the second edge of the second light-transmitting portion and the second side is not greater than the spacing between other parts of the second light-transmitting portion and the second side.

[0014] In some examples, a color resistance unit is further included in the first light-transmitting portion.

[0015] In a second aspect, the present invention provides a method for preparing a display substrate, wherein the preparation method comprises: providing a base substrate; forming a plurality of light-emitting devices and a pixel defining layer on the base substrate; the light-emitting device comprises a first electrode, a light-emitting layer and a second electrode stacked in sequence in a direction away from the base substrate; the pixel defining layer is arranged on a side of the first electrode away from the base substrate, and has a plurality of pixel openings extending through the layer in a thickness direction thereof; a first electrode and a pixel opening at least partially overlap in their orthographic projections on the base substrate; the display substrate has a first side and a second side arranged opposite to each other; for a portion of the first electrode located in the pixel opening, the distance between at least a portion of its surface away from the base substrate and the base substrate is unequal, and the distance between a position close to the first side and the base substrate is not less than the distance between a portion close to the second side and the base substrate.

[0016] In some examples, before forming multiple light-emitting devices and a pixel defining layer on the base substrate, the method further includes: forming a planarization layer on a side of the first electrode close to the base substrate; the planarization layer includes a flat portion and a plurality of protrusions, and the protrusions are located on a side of the flat portion away from the base substrate; one of the protrusions at least partially overlaps with a positive projection of a pixel opening on the base substrate, one of the first electrodes is located on a side of one of the protrusions away from the base substrate, and the distance between the protrusion and the flat portion decreases monotonically in a direction from the first side to the second side.

[0017] In some examples, the planarization layer is formed on the side of the first electrode close to the base substrate, including: forming an initial planarization layer on the side of the first electrode close to the base substrate; and forming a planarization layer including the flat portion and the plurality of protrusions using a composition process.

[0018] In some examples, it also includes: forming a first black matrix layer and a second black matrix layer in sequence on a side of the light-emitting device away from the base substrate; the first black matrix layer is provided with a plurality of first light-transmitting portions corresponding one-to-one to the pixel openings; the second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one-to-one to the pixel openings; the minimum distance between the first light-transmitting portion and the first side is smaller than the minimum distance between the second light-transmitting portion and the first side, and the minimum distance between the first light-transmitting portion and the second side is not smaller than the minimum distance between the second light-transmitting portion and the second side. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic plan view of a display substrate in the related art.

[0020] Figure 2 for Figure 1 The diagram shown is a schematic diagram of the film layer structure of the display substrate along the AB section.

[0021] Figure 3 It is a structural schematic diagram of a pixel driving circuit and a light-emitting device.

[0022] Figure 4 It is a schematic diagram of light emitted from a central control screen of a car in the related art.

[0023] Figure 5 It is a schematic diagram of the film layer structure of the display substrate provided by the present disclosure.

[0024] Figure 6 This is a schematic diagram of the emitted light when the display substrate provided by the present disclosure is applied to the central control screen of a car.

[0025] Figure 7 Schematic diagram of the specific structure of the planarization layer.

[0026] Figure 8 It is a schematic diagram of the specific structure of the protrusion.

[0027] Fig. 9 Several example diagrams of the first side surface of the protrusion.

[0028] Fig.10 The diagram is a schematic diagram showing that a protrusion includes a plurality of sub-protrusions.

[0029] Fig.11 Schematic diagrams of several ratios of the length of the portion of the protrusion located in the pixel opening to the length of the pixel opening.

[0030] Fig.12 Schematic diagram of the structure of the first black matrix layer and the second black matrix layer.

[0031] Fig.13 A specific process for forming a planarization layer.

[0032] Fig.14 A specific process for forming another planarization layer.

[0033] The accompanying drawings are denoted as follows:

[0034] 1. substrate; 2. pixel unit; 21. sub-pixel; 211. light-emitting device; 212. pixel driving circuit; 400. pixel opening; 211a. first electrode; 211b. light-emitting layer; 211c. second electrode; 132. support portion; 101. first gate insulating layer; 102. second gate insulating layer; 103. interlayer dielectric layer; 104. passivation film layer; 3. planarization layer; 4. pixel defining layer; 105. active layer; 106. gate; 107. source; 108. drain; 109. first plate; 110. second plate; 31. planar portion; 32. protrusion part; 321, first bottom surface; 322, first side surface; 323, first cut surface; 324, sub-protrusion; 5, encapsulation layer; 51, first inorganic encapsulation layer; 52, organic encapsulation layer; 53, second inorganic encapsulation layer; 8, touch layer; 61, first black matrix layer; 62, second black matrix layer; 81, first light-transmitting portion; 82, second light-transmitting portion; 7, organic protective layer; 30, initial planarization layer; 30a, initial first planarization layer; 30b, intermediate first planarization layer; 324a, first sub-protrusion; 324b, second sub-protrusion; 30c, initial second planarization layer. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0036] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0037] As used herein, "parallel" and "perpendicular" include the described situation and the situation similar to the described situation, and the range of the similar situation is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the error associated with the measurement of a specific quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism can be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity can also be, for example, a deviation within 5°.

[0038] It will be understood that when a layer or an 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 between the layer or element and the other layer or substrate.

[0039] Herein, "electrical connection" includes the situation where components are connected together through an element having some electrical function. There is no particular limitation on the "element having some electrical function" as long as it can transmit and receive electrical signals between connected components. Examples of "element having some electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other elements having various functions.

[0040] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0041] With the rapid development of new energy vehicles and OLED display technology, more and more automobile manufacturers are using OLED display devices as instrument panels, central control screens or co-pilot screens of new energy vehicles to enhance user experience.

[0042] Figure 1 FIG. 1 is a schematic plan view of an OLED display substrate in the related art. Figure 1 As shown, the display substrate includes a base substrate 1 and a plurality of pixel units 2 arranged in an array on the base substrate 1, wherein each pixel unit 2 includes a plurality of sub-pixels 21. Figure 1 As shown in FIG. 1 , a pixel unit 2 includes three sub-pixels 21 of red, green and blue. Figure 2 yes Figure 1 The schematic diagram of the cross-sectional structure of the substrate along the AB direction is shown in FIG. Figure 2 As shown, a sub-pixel 21 includes a light-emitting device 211 and a pixel driving circuit 212 electrically connected to the light-emitting device 211; the display substrate also includes a planarization layer 3 and a pixel defining layer 4 arranged on the side of the pixel driving circuit 212 away from the base substrate 1, wherein the pixel defining layer 4 has a plurality of pixel openings 400 extending through the thickness direction thereof.

[0043] Figure 3 is a schematic diagram of the structure of a sub-pixel 21. Figure 3 As shown, the pixel driving circuit 212 includes a thin film transistor and a capacitor structure; the light emitting device 211 includes a first electrode 211a, a light emitting layer 211b and a second electrode 211c stacked in sequence in a direction away from the base substrate 1. Among them, a first electrode 211a and a positive projection of a pixel opening 400 on the base substrate 1 at least partially overlap.

[0044] Thin film transistors can be Figure 3 As shown in the top-gate type, the thin film transistor may include an active layer 105, a first gate insulating layer 101, a gate electrode 106, a second gate insulating layer 102, an interlayer dielectric layer 103, a source electrode 107, and a drain electrode 108. Specifically, the active layer 105 may be formed on the base substrate 1, the first gate insulating layer 101 covers the base substrate 1 and the active layer 105, the gate electrode 106 is formed on the side of the first gate insulating layer 101 away from the active layer 105, the second gate insulating layer 102 covers the gate electrode 106 and the first gate insulating layer 101, the interlayer dielectric layer 103 covers the second gate insulating layer 102, the source electrode 107 and the drain electrode 108 are formed on the side of the interlayer dielectric layer 103 away from the base substrate 1 and are respectively located on the opposite sides of the gate electrode 106, and the source electrode 107 and the drain electrode 108 may be in contact with the opposite sides of the active layer 105 through vias (e.g., metal vias), respectively. The interlayer dielectric layer 103 is made of inorganic materials, such as silicon oxide, silicon nitride and other inorganic materials, to achieve the effect of blocking water and oxygen and blocking alkaline ions. It should be understood that the thin film transistor can also be a bottom gate type.

[0045] Capacitor structure such as Figure 3As shown, the first electrode plate 109 and the second electrode plate 110 may be included. The first electrode plate 109 is arranged in the same layer as the gate electrode 106. The second electrode plate 110 is located between the second gate insulating layer 102 and the interlayer dielectric layer 103, and is arranged opposite to the first electrode plate 109. The materials of the gate electrode 106, the first electrode plate 109, and the second electrode plate 110 may include metal materials or alloy materials, such as molybdenum, aluminum, and titanium. The source electrode 107 and the drain electrode 108 may include metal materials or alloy materials, such as a metal single layer or multilayer structure formed by molybdenum, aluminum, and titanium. For example, the multilayer structure is a multi-metal layer stack, such as a titanium, aluminum, and titanium three-layer metal stack (Ti / Al / Ti).

[0046] In the related art, when the thin film transistor is a top-gate type, a planarization layer 3 may be formed before the light emitting device 211 is formed. The planarization layer 3 may be a single-layer structure or a multi-layer structure. The planarization layer 3 is usually formed of organic materials, such as photoresist, acrylic polymer, silicon polymer, etc. Figure 2 As shown, the planarization layer 3 is formed between the interlayer dielectric layer 103 and the first electrode 211a. Figure 3 The first electrode 211a can be electrically connected to the drain electrode 108 through a metal via. The first electrode 211a can be an anode, which can be made of materials such as ITO (indium tin oxide), indium zinc oxide (IZO), and zinc oxide (ZnO). The pixel defining layer 4 can cover the planarization layer 3 and can be made of organic materials, such as organic materials such as photoresist. The light-emitting layer 211b is located in the pixel opening 400 and is formed on the first electrode 211a. The light-emitting layer 211b can include small molecule organic materials or polymer molecule organic materials, and can be fluorescent light-emitting materials or phosphorescent light-emitting materials. The light-emitting layer 211b may further include an electron injection layer (EIL), an electron transport layer (ETL), a hole injection layer (HIL), a hole transport layer (HTL) and other light-emitting functional layers according to different actual needs; the second electrode 211c covers the light-emitting layer 211b, and the polarity of the second electrode 211c is opposite to that of the first electrode 211a; the second electrode 211c may be a cathode, and the cathode may be made of metal materials such as lithium (Li), aluminum (Al), magnesium (Mg), and silver (Ag).

[0047] It should be noted that in the related art, the planarization layer 3 is usually a film layer structure with uniform thickness and a smooth surface. Its functions are: on the one hand, in the preparation process of the display substrate, it provides a flat base surface, which is conducive to the uniform deposition and growth of each film layer thereon, so as to ensure the quality and performance of each film layer; on the other hand, the uniform thickness of the planarization layer 3 at each position can make the surface of the light-emitting layer 211b of each light-emitting device 211 formed thereon smooth, so that the light emitted by the light-emitting device 211 to the light-emitting side of the display substrate can be evenly distributed in all directions.

[0048] Next, the technical problems existing in the related art when OLED display substrates are used in automobile display screens are introduced. Figure 4 This is a schematic diagram of the projection phenomenon on the windshield when the OLED display substrate is applied to a car. Figure 4 As shown in FIG. 1 , as the size of the display substrate increases, part of the light emitted from the portion close to the windshield side will be irradiated on the windshield. Due to the reflection effect of the windshield, the light projected on the windshield will be reflected to the driver's side, interfering with the driver's sight. That is, in the related art, the first electrode 211a and the light-emitting layer 211b of the light-emitting device 211 have uniform thickness at each position and are located on the same horizontal plane (for example, Figure 3 As shown), the light emitted by each light emitting device 211 of the display substrate is evenly distributed in all directions, wherein the projection phenomenon of the light emitted by the display substrate close to the windshield side on the windshield will interfere with the driver's sight.

[0049] In order to solve at least one of the above technical problems, on the one hand, an embodiment of the present disclosure provides a display substrate. Figure 5 Schematic diagram of a cross section of a display substrate provided by an embodiment of the present disclosure. Figure 5 As shown, the display substrate provided by the present disclosure includes a base substrate 1, a plurality of light-emitting devices 211 disposed on the base substrate 1, and a pixel defining layer 4. The light-emitting device 211 includes a first electrode 211a, a light-emitting layer 211b, and a second electrode 211c stacked in sequence in a direction away from the base substrate 1; the pixel defining layer 4 is disposed on a side of the first electrode 211a away from the base substrate 1, and has a plurality of pixel openings 400 penetrating along its thickness direction. The orthographic projections of a first electrode 211a and a pixel opening 400 on the base substrate 1 at least partially overlap. Figure 5As shown, the display substrate has a first side S1 and a second side S2 that are arranged opposite to each other. For the portion of the first electrode 211a located in the pixel opening 400, the spacing between at least a portion of the position of the surface of the first electrode 211a that is away from the substrate substrate 1 and the substrate substrate 1 is not equal, and the spacing between the position close to the first side S1 and the substrate substrate 1 is not less than the spacing between the portion close to the second side S2 and the substrate substrate 1. For example, for the portion of the first electrode 211a located in the pixel opening 400, the spacing between the position close to the first side S1 and the substrate substrate 1 is d1, and the spacing between the portion close to the second side S2 and the substrate substrate 1 is d2. In the embodiment provided by the present disclosure, d1 is not less than d2.

[0050] Those skilled in the art can understand that the first side S1 of the display substrate may refer to a side close to the windshield, and the second side S2 may refer to a side close to the driver. Figure 6 Schematic diagram of the outgoing light of the central control screen of a car when the display substrate provided by the present disclosure is used, compared with Figure 4 and Figure 6 It can be found that in the embodiment of the present disclosure, by setting the portion of the first electrode 211a located in the pixel opening 400, the distance between the position close to the first side S1 and the substrate 1 is not less than the distance between the portion close to the second side S2 and the substrate 1, that is, the distance between the portion of the first electrode 211a located in the pixel opening 400 close to the windshield side and the substrate 1 is not less than the distance between the position close to the driver side and the substrate 1. At the same time, since the light-emitting layer 211b is arranged on the side of the first electrode 211a away from the substrate 1, the distance between the position of the light-emitting layer 211b close to the windshield side and the substrate 1 is also not less than the distance between the position close to the driver side and the substrate 1. At this time, due to The height of the part of the light-emitting device 211 close to the windshield side is greater than the height of the part close to the driver side (the height here refers to the distance between the surface of the light-emitting device 211 close to the light-emitting side and the base substrate 1), so that the light originally projected onto the windshield side can be deflected toward the driver side as a whole, and at least the following beneficial effects can be achieved: on the one hand, the light projected onto the windshield by the display substrate is reduced, thereby reducing the light reflected from the windshield into the driver's eyes and reducing the interference of the projection phenomenon on the driver's line of sight; on the other hand, the light emitted from the display substrate to the driver's side is increased, which can improve the energy utilization rate of the light-emitting device 211 and avoid energy waste, while enhancing the driver's visual experience and improving the information transmission effect of the display screen.

[0051] Next, the embodiments are described in detail.

[0052] Figure 7 A specific embodiment of the display substrate provided by the present disclosure. Figure 7As shown, the display substrate provided by the present disclosure further includes a planarization layer 3 arranged between the base substrate 1 and the first electrode 211 a . Figure 8 is a structural diagram of the planarization layer, such as Figure 8 As shown, the planarization layer 3 includes a flat portion 31 and a plurality of protrusions 32, wherein the protrusions 32 are located on the side of the flat portion 31 away from the base substrate 1. Specifically, one protrusion 32 at least partially overlaps with the orthographic projection of one pixel opening 400 on the base substrate 1, one first electrode 211a is located on the side of one protrusion 32 away from the base substrate 1, and in the direction from the first side S1 to the second side S2, the spacing between the protrusion 32 and the flat portion 31 decreases monotonically. For example, the spacing between the portion of the protrusion 32 close to the first side S1 and the flat portion 32 is d3, and the spacing between the portion close to the second side S2 and the flat portion 32 is d4, wherein d3 is greater than d4.

[0053] The above embodiment provides a specific solution for realizing that the distance between the position of the surface of the first electrode 211a close to the light emitting side close to the first side S1 and the base substrate 1 is not less than the distance between the position of the surface of the first electrode 211a close to the second side S2 and the base substrate 1. It should be noted that those skilled in the art can understand that other methods can also be used to realize the present disclosure. Figure 5 The provided display substrate, for example, forms a structure similar to the protrusion 32 at a position corresponding to the first electrode 211 on other dielectric layers (such as the first gate insulating layer 101, the second gate insulating layer 102, or the interlayer dielectric layer 103) between the first electrode 211a and the base substrate 1. However, the solution of forming the protrusion 32 on the planarization layer 3 provided in the present disclosure can be used as a preferred embodiment, and its advantage over forming the protrusion 32 on other film layers is that, on the one hand, the distance between the planarization layer 3 and the first electrode 211a is the smallest relative to other film layers, and at this time, the influence and adjustment effect of the protrusion 32 on the first electrode 211a are most obvious, so the effect can be maximized and the cost can be reduced; on the other hand, forming the protrusion 32 on the planarization layer 3 can avoid the influence on the pixel driving circuit 212 or other signal lines when the protrusion 32 is formed on other dielectric layers.

[0054] Fig. 9 FIG. 3 is a schematic diagram of an optional shape of the protrusion 32. Fig. 9 As shown, the protrusion 32 includes a first bottom surface 321 and a first side surface 322. The first side surface 322 includes a plane (refer to Fig. 9 (a)), convex surface (refer to Fig. 9 (b)), or concave (refer to Fig. 9At least one of (c)). The intersection of the first bottom surface 321 and the first side surface 322 is a first intersection line (not shown in the figure), and the tangent plane of the first side surface 322 passing through any point on the first intersection line is called a first tangent plane 323. Preferably, the angle θ between the first tangent plane 323 and the first bottom surface 321 is greater than 0° and less than or equal to 30°. It can be understood by those skilled in the art that when the first side surface 322 is a plane, its first tangent plane 323 overlaps with the first side surface 322.

[0055] In the above example, the angle between the first cut surface 323 and the first bottom surface 321 of the protrusion 32 is (0°, 30°], which can effectively deflect the light close to the windshield side toward the driver's side on the one hand, and avoid increasing the thickness of the display substrate due to a too large angle on the other hand.

[0056] Fig.10 FIG. 3 is another schematic diagram of the structure of the protrusion 32. Fig.10 As shown, the protrusion 32 includes a plurality of sub-protrusions 324 stacked in a direction away from the substrate 1, for example, Fig.10 The schematic diagram of the protrusion 32 including three sub-protrusions 324 is shown. In this example, the angle θ between the first cut surface 323 of the protrusion 32 and the first bottom surface 321 can be flexibly and effectively adjusted by superimposing the sub-protrusions 324, so as to better adjust the deflection angle of the emitted light.

[0057] Fig.11 Schematic diagram of the portion of the protrusion located in the pixel opening occupying different proportions of the pixel opening. Fig.11 As shown, in the direction from the first side S1 to the second side S2, the length of the pixel opening 400 is L1, and the length of the portion of the protrusion 32 located in the pixel opening 400 is L2. For example, the ratio of L2 to L1 may be 0.5:1 (eg Fig.11 ), or 1:1 (as shown in (a) Fig.11 As shown in (b)). Of course, the ratio of L2 to L1 may also be other cases, such as 0.1:1, 0.2:1, 1 / 3:1, etc. In practical applications, those skilled in the art can adjust the ratio of L2 to L1 according to the required light output deflection angle to achieve the required light output effect.

[0058] Fig.12 Schematic diagram of another display substrate provided by the present disclosure. Fig.12As shown, the display substrate further includes a first black matrix layer 61 and a second black matrix layer 62 sequentially arranged on the side of the light emitting device 211 away from the base substrate 1. The first black matrix layer 61 is provided with a plurality of first light-transmitting portions 81 corresponding to the pixel openings 400 one by one; the second black matrix layer 62 is provided with a plurality of second light-transmitting portions 82 corresponding to the pixel openings 400 one by one. In the display substrate provided by the present disclosure, the minimum distance between the first light-transmitting portion 81 and the first side S1 is less than the minimum distance between the second light-transmitting portion 82 and the first side S1. For example Fig.12 As shown, the minimum distance between the first light-transmitting portion 81 and the first side S1 is d11, and the minimum distance between the second light-transmitting portion 82 and the first side S1 is d21, wherein d11 is smaller than d21.

[0059] In other words, the first black matrix layer 61 is provided with a plurality of first light-transmitting portions 81 corresponding one-to-one to the pixel openings 400, and the orthographic projections of the first light-transmitting portions 81 on the base substrate 1 are located in the corresponding pixel openings 400; the second black matrix layer 62 is provided with a plurality of second light-transmitting portions 82 corresponding one-to-one to the pixel openings 400. The orthographic projections of the first edges of the second light-transmitting portions 82 on the base substrate 1 overlap with the orthographic projections of the first light-transmitting portions 81 on the base substrate 1; wherein the first edge of the second light-transmitting portion 82 satisfies: the spacing between the first edge and the first side S1 is not greater than the spacing between the other parts of the second light-transmitting portion 82 and the first side S1.

[0060] In the above example, the first side S1 may refer to the windshield side, and the second side S2 may refer to the driver side. By setting the minimum distance between the first light-transmitting portion 81 and the first side S1 to be smaller than the minimum distance between the second light-transmitting portion 82 and the first side S1, part of the light emitted to the windshield side (for example, Fig.12 The light R1) in the windshield is prevented from being projected onto the windshield, thereby reducing the interference of the projection phenomenon of the windshield on the driver's vision.

[0061] For further information, please refer to Fig.12 , the minimum distance between the first light-transmitting portion 81 and the second side S2 is not less than the minimum distance between the second light-transmitting portion 82 and the second side S2. For example, the minimum distance between the first light-transmitting portion 81 and the second side S2 is Fig.12 The marked d12, the minimum distance between the second light-transmitting portion 82 and the second side S2 is Fig.12 The marked d22, wherein d12 is not less than d22.

[0062] In other words, the orthographic projection of the second edge of the second light-transmitting portion 82 on the base substrate 1 and the orthographic projection of the first light-transmitting portion 81 on the base substrate 1 do not overlap; wherein, the second edge of the second light-transmitting portion 82 satisfies: the spacing between the second edge and the second side S2 is not greater than the spacing between other parts of the second light-transmitting portion 82 and the second side S2.

[0063] In the above example, the first side S1 still refers to the windshield side, and the second side S2 still refers to the driver side. By setting the minimum distance between the first light-transmitting portion 81 and the second side S2 to be not less than the minimum distance between the second light-transmitting portion 82 and the second side S2, it is possible to prevent the light originally emitted to the windshield side from being blocked by the second black matrix layer 62 when it is deflected to the driver side and cannot be emitted to the driver side (refer to Fig.12 The light R2 in the image is removed, thereby avoiding the influence of the second black matrix layer 62 on the display brightness and display effect on the driver side.

[0064] In some examples, the display substrate further includes a color resist unit located in the first light-transmitting portion 81. For example, the color resist unit includes red, green, and blue color resist units, and the colors thereof are generally set according to the color of the light emitted by the light-emitting layer 211b in the pixel opening 400 corresponding to the first light-transmitting portion 81. It should be noted that an organic protective layer 7 is further provided between the first black matrix layer 61 and the second black matrix layer 62, and the organic protective layer 7 can flatten and protect the first black matrix layer 61, so as to facilitate the subsequent formation of the second black matrix layer 62.

[0065] In some examples, reference Fig.12 , the display substrate provided by the present disclosure also includes an encapsulation layer 5, which is arranged on the side of the light-emitting device 211 away from the base substrate 1. For example, the encapsulation layer 5 may include a first inorganic encapsulation layer 51, an organic encapsulation layer 52 and a second inorganic encapsulation layer 53 stacked in sequence. Among them, the first inorganic encapsulation layer 51 and the second inorganic encapsulation layer 52 are used to prevent water and oxygen from entering the light-emitting layer 211b of the display substrate, and can be made of inorganic materials such as silicon nitride and silicon oxide. The organic encapsulation layer 52 is used to achieve a planarization effect to facilitate the production of the second inorganic encapsulation layer 53, and can be made of materials such as acrylic-based polymers and silicon-based polymers. The first inorganic encapsulation layer 51 and the second inorganic encapsulation layer 53 can be made by a chemical vapor deposition process, but not limited to this, and can also be made by a physical vapor deposition process, etc.; and the organic encapsulation layer 52 is made by an inkjet printing process, but not limited to this, and can also be made by a spraying process, etc.

[0066] In some examples, the base substrate 1 may be a flexible substrate to improve the flexibility of the display substrate, so that the display substrate can have properties such as bendable and foldable, so as to expand the application range of the display substrate; but not limited to this, the base substrate 1 can also be set to be rigid, and the specific material of the base substrate 1 can be determined according to the actual needs of the product. In addition, the base substrate 1 can be a single-layer structure or a multi-layer structure. For example, the base substrate 1 may include a polyimide layer and a buffer layer (not shown in the figure) stacked in sequence. In other embodiments, the base substrate 1 may include a plurality of polyimide layers and buffer layers stacked in sequence; the buffer layer may be made of materials such as silicon nitride and silicon oxide to achieve the effect of blocking water and oxygen and blocking alkaline ions; it should be noted that the structure of the base substrate 1 is not limited to this and can be determined according to actual needs.

[0067] In some examples, reference Fig.12 The display substrate provided in the present disclosure further includes a touch layer 8, which is arranged on the side of the encapsulation layer 5 away from the base substrate 1. The touch layer 8 can adopt a flexible single layer (Flexible Single Layer On Cell, FSLOC) touch structure or a flexible multi-layer (Flexible Multi-Layer On Cell, FMLOC) touch structure, which is not limited in the present disclosure.

[0068] In some examples, reference Figure 3 The display substrate also includes a support portion 132, which is arranged on the side of the pixel defining layer 4 away from the base substrate 1. The support portion 132 can support the protective film layer (not shown in the figure) to prevent the protective film layer from contacting the first electrode 112 or other wirings and causing the first electrode 112 or other wirings to be easily damaged. It should be noted that this protective film layer mainly appears in the process of transferring semi-finished products to avoid damage to the semi-finished products during the transfer process. Specifically: in the process of transferring the substrate with the support portion 132 to the evaporation production line, a protective film layer can be covered, and when the luminescent material needs to be evaporated, the protective film layer will be removed.

[0069] In the display substrate provided by the present disclosure, the pixel driving circuit 212 may include a plurality of thin film transistors T1, T2, T3, T4, T5, T6 and T7, a plurality of signal lines connected to the plurality of thin film transistors T1, T2, T3, T4, T5, T6 and T7, and a storage capacitor Cst, wherein the plurality of signal lines include a gate line GL (i.e., a scanning signal line), a light emitting control line EM, an initialization line RL, a data line DAT and a first power line VDD. The gate line GL may include a first gate line GLn and a second gate line GLn-1, for example, the first gate line GLn may be used to transmit a gate scanning signal, and the second gate line GLn-1 may be used to transmit a reset signal. The light emitting control line EM may be used to transmit a light emitting control signal. Thus, the pixel circuit is a 7T1C pixel circuit.

[0070] It should be noted that the embodiments of the present disclosure include but are not limited to this, and the pixel circuit may also adopt other types of circuit structures, such as a 7T2C structure or a 9T2C structure, etc., and the embodiments of the present disclosure are not limited to this.

[0071] In a second aspect, the present disclosure provides a method for preparing a display substrate, where the display substrate is the display substrate provided in any example of the first aspect.

[0072] The method for preparing a display substrate provided in the present disclosure includes:

[0073] Step S1, providing a base substrate 1. Exemplarily, the base substrate 1 may be a flexible substrate or a rigid substrate. In addition, the base substrate 1 may be a single-layer structure or a multi-layer structure. For example, the base substrate 1 may include a polyimide layer and a buffer layer stacked in sequence; or, in other embodiments, the base substrate 1 may include a plurality of polyimide layers and a buffer layer stacked in sequence; the buffer layer may be made of materials such as silicon nitride and silicon oxide to achieve the effect of blocking water and oxygen and blocking alkaline ions.

[0074] Step S2: forming a plurality of light emitting devices 211 and a pixel defining layer 4 on the base substrate 1. Figure 5, wherein the light emitting device 211 comprises a first electrode 211a, a light emitting layer 211b and a second electrode 211c which are sequentially stacked in a direction away from the substrate 1. The pixel boundary 4 is arranged on the side of the first electrode 211a away from the substrate 1, and has a plurality of pixel openings 400 penetrating along the thickness direction thereof. The orthographic projections of one first electrode 211a and one pixel opening 400 on the substrate 1 at least partially overlap. The display substrate has a first side S1 and a second side S2 which are arranged oppositely; for the portion of the first electrode 211a located in the pixel opening 400, the distance between at least a portion of the surface away from the substrate 1 and the substrate 1 is not equal, and the distance between the position close to the first side S1 and the substrate 1 (e.g. d1) is not less than the distance between the portion close to the second side S2 and the substrate 1 (e.g. d2).

[0075] Those skilled in the art can understand that the first side S1 of the display substrate can refer to the side close to the windshield, and the second side S2 can refer to the side close to the driver. In the embodiment of the present disclosure, by setting the portion of the first electrode 211a located in the pixel opening 400, the distance between the position close to the first side S1 and the substrate substrate 1 is not less than the distance between the portion close to the second side S2 and the substrate substrate 1, that is, the distance between the portion of the first electrode 211a located in the pixel opening 400 close to the windshield side and the substrate substrate 1 is not less than the distance between the position close to the driver side and the substrate substrate 1. At the same time, since the light-emitting layer 211b is set on the side of the first electrode 211a away from the substrate substrate 1, the distance between the position of the light-emitting layer 211b close to the windshield side and the substrate substrate 1 is also not less than the distance between the position close to the driver side and the substrate substrate 1. At this time, due to the light-emitting device 211a The height of the portion of the light emitting device 211 close to the windshield is greater than the height of the portion close to the driver's side (the height here refers to the distance between the surface of the light emitting device 211 close to the light emitting side and the base substrate 1), so that the light originally projected onto the windshield side can be deflected toward the driver's side as a whole, and at least the following beneficial effects can be achieved: on the one hand, the light projected onto the windshield by the display substrate is reduced, thereby reducing the light reflected from the windshield to the driver's eyes and reducing the interference of the projection phenomenon on the driver's line of sight; on the other hand, the light emitted from the display substrate to the driver's side is increased, which can improve the energy utilization rate of the light emitting device 211 and avoid energy waste, while enhancing the driver's visual experience and improving the information transmission effect of the display screen.

[0076] As a specific embodiment, in the above step S2, before forming a plurality of light emitting devices 211 and a pixel defining layer 4 on the base substrate 1, the step further includes:

[0077] Step SS1: Form a planarization layer 3 on the side of the first electrode 211a close to the base substrate 1. Figure 7 and Figure 8 , wherein the planarization layer 3 includes a flat portion 31 and a plurality of protrusions 32, wherein the plurality of protrusions 32 are located on a side of the flat portion 31 away from the base substrate 1. A protrusion 32 at least partially overlaps with a positive projection of a pixel opening 400 on the base substrate 1, a first electrode 211a is located on a side of a protrusion 32 away from the base substrate 1, and in a direction from the first side S1 to the second side S2, the spacing between the protrusion 32 and the flat portion 31 decreases monotonically (e.g. Figure 8 (d3>d4).

[0078] Fig.13 This is the preparation process of forming a planarization layer 3 on the side of the first electrode 211a close to the base substrate 1 in the above step SS1. Fig.13 As shown, a planarization layer 3 is formed on a side of the first electrode 211a close to the base substrate 1, including:

[0079] Step SS1a: forming an initial planarization layer 30 on a side of the first electrode 211a close to the base substrate 1 , or on a side of the layer where the pixel driving circuit 212 is located away from the base substrate 1 .

[0080] Step SS1b, using a patterning process to form a planarization layer 3 including a flat portion 31 and a plurality of protrusions 32. Specifically, in the present disclosure, the expression "patterning process" generally includes steps such as coating, exposure, development, etching, and stripping of photoresist. Preferably, when the protrusions 32 are formed using a patterning process, a halftone mask can be used for exposure, development, etc.

[0081] In other examples, the protrusion 32 includes a plurality of sub-protrusions 324 (eg, Fig.10 shown). Fig.14 The preparation process of forming the planarization layer 3 when the protrusion 32 includes two sub-protrusions 324. Fig.14 As shown, the two sub-protrusions 324 are respectively referred to as the first sub-protrusion 324a and the second sub-protrusion 324b. In step SS1, a planarization layer 3 is formed on a side of the first electrode 211a close to the base substrate 1, including:

[0082] Step SS1a, forming an initial first planarization layer 30a on a side of the first electrode 211a close to the base substrate 1, or on a side of the layer where the pixel driving circuit 212 is located away from the base substrate 1.

[0083] Step SS1b: using a patterning process, forming a middle first planarization layer 30b including a planar portion 31 and a plurality of first sub-protrusions 324a.

[0084] Step SS1c: forming an initial second planarization layer 30c on the side of the middle first planarization layer 30b away from the substrate 1.

[0085] Step SS1d: Using a patterning process, a plurality of second sub-protrusions 324b are formed to form a protrusion 32 including two sub-protrusions 324, and a planarization layer 3 including a flat portion 31 and a plurality of protrusions 32. Similarly, when the second sub-protrusions are formed using a patterning process, a halftone mask may be used for exposure, development, and the like.

[0086] In some examples, after forming a plurality of light emitting devices 211 and a pixel defining layer 4 on the base substrate 1 in step S2, the preparation method further includes:

[0087] Step S3: On the side of the light emitting device 211 away from the substrate 1, a first black matrix layer 61 and a second black matrix layer 62 are sequentially formed. Fig.12 The first black matrix layer 61 is provided with a plurality of first light-transmitting portions 81 corresponding to the pixel openings 400 one by one; the second black matrix layer 62 is provided with a plurality of second light-transmitting portions 82 corresponding to the pixel openings 400 one by one. Specifically, the minimum distance between the first light-transmitting portion 81 and the first side S1 (e.g. Fig.12 The distance d11 marked in the figure is smaller than the minimum distance between the second light-transmitting portion 82 and the first side S1 (eg Fig.12 Also, the minimum distance between the first light-transmitting portion 81 and the second side S2 (e.g. Fig.12 The distance d12 marked in the figure is not less than the minimum distance between the second light-transmitting portion 82 and the second side S2 (e.g. Fig.12 d22 marked in the figure).

[0088] In the above example, the first side S1 still refers to the windshield side, and the second side S2 still refers to the driver's side. By setting the minimum distance between the first light-transmitting portion 81 and the first side S1 to be smaller than the minimum distance between the second light-transmitting portion 82 and the first side S1, part of the light emitted to the windshield side (for example, Fig.12 By setting the minimum distance between the first light-transmitting portion 81 and the second side S2 to be not less than the minimum distance between the second light-transmitting portion 82 and the second side S2, it is possible to prevent the light originally emitted to the windshield from being blocked by the second black matrix layer 62 when it is deflected to the driver's side and cannot be emitted to the driver's side (refer to Fig.12 The light R2 in the image is removed, thereby avoiding the influence of the second black matrix layer 62 on the display brightness and display effect on the driver side.

[0089] In some examples, the display substrate further includes an encapsulation layer 5 disposed on a side of the second electrode 211c away from the base substrate 1, such as Fig.12 As shown, at this time, the preparation method further includes the steps of sequentially forming the first inorganic encapsulation layer 51, the organic encapsulation layer 52 and the second inorganic encapsulation layer 53 by evaporation, deposition or inkjet process.

[0090] In some examples, the display substrate further includes a touch layer 8 disposed on a side of the encapsulation layer 5 away from the base substrate 1, such as Fig.12 As shown, at this time, the preparation method also includes: forming a touch layer 8, and attaching the touch layer 8 to the display layer by optical adhesive. Those skilled in the art should understand that the display layer here refers to the layer including the layer where the pixel driving circuit 212 is located, the planarization layer 3, the layer where the light-emitting device 211 is located, the pixel defining layer 4 and the encapsulation layer 5.

[0091] It should be noted that although the steps of the method in the present disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in this specific order, or that all the steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps, etc. In addition, some of the above steps may be performed in parallel or sequentially, etc., and are not limited to the specific operation order described above.

[0092] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A display substrate, comprising a base substrate, a plurality of light-emitting devices arranged on the base substrate, and a pixel defining layer; the light-emitting device comprises a first electrode, a light-emitting layer, and a second electrode stacked in sequence in a direction away from the base substrate; the pixel defining layer is arranged on a side of the first electrode away from the base substrate, and has a plurality of pixel openings penetrating along a thickness direction thereof; the orthographic projection of one of the first electrodes and one of the pixel openings on the base substrate at least partially overlaps; in, The display substrate has a first side and a second side that are arranged opposite to each other; for the portion of the first electrode located in the pixel opening, the distance between at least a portion of its surface facing away from the substrate and the substrate is unequal, and the distance between a position close to the first side and the substrate is not less than the distance between a position close to the second side and the substrate.

2. The display substrate according to claim 1, wherein: Also includes a planarization layer disposed between the base substrate and the first electrode; The planarization layer comprises a planar portion and a plurality of protruding portions, wherein the protruding portions are located on a side of the planar portion away from the substrate; One of the protrusions at least partially overlaps with a positive projection of the pixel opening on the substrate, one of the first electrodes is located on a side of the protrusion that is away from the substrate, and in a direction from the first side to the second side, the distance between the protrusion and the flat portion decreases monotonically.

3. The display substrate according to claim 2, wherein: The protrusion includes a first bottom surface and a first side surface; the intersection of the first bottom surface and the first side surface is a first intersection line, and the tangent plane of the first side surface passing through any point on the first intersection line is called a first tangent plane; An included angle between the first cut surface and the first bottom surface is greater than 0° and less than or equal to 30°.

4. The display substrate according to claim 3, wherein: The first side surface includes at least one of a flat surface, a convex surface, or a concave surface.

5. The display substrate according to any one of claims 1 to 4, wherein: The protrusion includes a plurality of sub-protrusions stacked in a direction away from the substrate base.

6. The display substrate according to claim 1, wherein: It also includes a first black matrix layer and a second black matrix layer which are sequentially arranged on a side of the light emitting device away from the base substrate; The first black matrix layer is provided with a plurality of first light-transmitting portions corresponding one to one with the pixel openings; The second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one to one with the pixel openings; A minimum distance between the first light-transmitting portion and the first side is smaller than a minimum distance between the second light-transmitting portion and the first side.

7. The display substrate according to claim 6, wherein: A minimum distance between the first light-transmitting portion and the second side is not less than a minimum distance between the second light-transmitting portion and the second side.

8. The display substrate according to claim 6, wherein: In a direction from the first side to the second side, a length ratio of the second light-transmitting portion to the first light-transmitting portion is: 0.9:1～1.5:1。 9. The display substrate according to claim 1, wherein: It also includes a first black matrix layer and a second black matrix layer which are sequentially arranged on a side of the light emitting device away from the base substrate; The first black matrix layer is provided with a plurality of first light-transmitting portions corresponding to the pixel openings one by one; the orthographic projections of the first light-transmitting portions on the base substrate are located in the corresponding pixel openings; The second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one to one with the pixel openings; The orthographic projection of the first edge of the second light-transmitting portion on the base substrate overlaps with the orthographic projection of the first light-transmitting portion on the base substrate; A distance between a first edge of the second light-transmitting portion and the first side is not greater than a distance between other portions of the second light-transmitting portion and the first side.

10. The display substrate according to claim 9, wherein: The orthographic projection of the second edge of the second light-transmitting portion on the base substrate has no overlap with the orthographic projection of the first light-transmitting portion on the base substrate; the distance between the second edge of the second light-transmitting portion and the second side is not greater than the distance between other parts of the second light-transmitting portion and the second side.

11. The display substrate according to claim 6 or 9, wherein: Also included is a color resistance unit located in the first light-transmitting portion.

12. A method for preparing a display substrate according to any one of claims 1 to 11, wherein: The preparation method comprises: providing a substrate base plate; A plurality of light-emitting devices and a pixel defining layer are formed on the substrate; the light-emitting device comprises a first electrode, a light-emitting layer and a second electrode which are stacked in sequence in a direction away from the substrate; the pixel defining layer is arranged on a side of the first electrode away from the substrate, and has a plurality of pixel openings extending through the pixel defining layer in a thickness direction; a first electrode and a pixel opening have at least a partial overlap in their orthographic projections on the substrate; the display substrate has a first side and a second side which are arranged opposite to each other; for a portion of the first electrode located in the pixel opening, the distance between at least a portion of its surface away from the substrate and the substrate is unequal, and the distance between a position close to the first side and the substrate is not less than the distance between a portion close to the second side and the substrate.

13. The preparation method according to claim 12, wherein: Before forming a plurality of light emitting devices and a pixel defining layer on the substrate, the method further comprises: Forming a planarization layer on a side of the first electrode close to the base substrate; The planarization layer comprises a planar portion and a plurality of protruding portions, wherein the protruding portions are located on a side of the planar portion away from the substrate; One of the protrusions at least partially overlaps with a positive projection of the pixel opening on the substrate, one of the first electrodes is located on a side of the protrusion that is away from the substrate, and in a direction from the first side to the second side, the distance between the protrusion and the flat portion decreases monotonically.

14. The preparation method according to claim 13, wherein: The step of forming a planarization layer on a side of the first electrode close to the base substrate comprises: forming an initial planarization layer on a side of the first electrode close to the base substrate; A planarization layer including the planar portion and the plurality of protrusions is formed by a patterning process.

15. The preparation method according to claim 12, wherein: Also includes: On a side of the light emitting device away from the base substrate, a first black matrix layer and a second black matrix layer are sequentially formed; The first black matrix layer is provided with a plurality of first light-transmitting portions corresponding one to one with the pixel openings; The second black matrix layer is provided with a plurality of second light-transmitting portions corresponding one to one with the pixel openings; The minimum distance between the first light-transmitting portion and the first side is smaller than the minimum distance between the second light-transmitting portion and the first side, and the minimum distance between the first light-transmitting portion and the second side is not smaller than the minimum distance between the second light-transmitting portion and the second side.

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