Display substrate and display apparatus

Abstract

A display substrate and a display apparatus. The display substrate comprises a driving structure layer, a planarization layer and a light-emitting structure layer, which are sequentially stacked on a base in a direction away from the base, wherein the light-emitting structure layer comprises a plurality of light-emitting elements and a pixel definition layer that separates adjacent light-emitting elements, the pixel definition layer being provided with a plurality of pixel openings, and the light-emitting elements being arranged at the pixel openings; areas defined by the pixel openings are light-emitting areas, and areas outside the light-emitting areas are non-light-emitting areas; and in the non-light-emitting areas, the planarization layer or / and at least one insulating layer is / are provided with a light extraction structure, and the light extraction structure is configured to concentrate light emitted from the light-emitting elements in a direction perpendicular to the base.

Description

Display substrate and display device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 25, 2023, with application number 202310754037.2 and invention name “A display substrate and display device”, the contents of which should be understood as incorporated into this application by reference. Technical Field

[0002] The embodiments of the present disclosure relate to, but are not limited to, the display field, and specifically relate to a display substrate and a display device. Background Art

[0003] Organic light-emitting diode (OLED) display products have gradually become mainstream products in the display field due to their advantages such as self-luminescence, wide viewing angle, high contrast, low power consumption, and extremely high response speed. Currently, there are two technical routes for the production of OLED display panels: one is the red, green, and blue (RGB) primary color OLEDs emitting light separately, which has the advantages of simple and mature process and easy operation. However, due to the need for high-precision masks and precise alignment when preparing high-resolution display screens, the production capacity is low and the cost is high. In addition, due to the large differences in the lifespan, excitation rate, and attenuation of the RGB primary color OLEDs, color deviation of the OLED display panel is easily caused. The other is white light OLED + color film technology, which does not require mask alignment and usually adopts bottom emission type light emission method, which greatly simplifies the evaporation process and can be used to prepare large-size high-resolution OLED display panels.

[0004] Among the light emitted by the OLED device of the OLED display substrate, light with a large exit angle will be reflected back into the display substrate and cannot be emitted. Some technologies change the path of light by adding a light extraction layer to reduce the light confined within the display substrate. For example, a concave-convex lens structure 2' is formed on the surface of the flat layer, and then a concave-convex anode and light-emitting layer are formed above the flat layer. The light emitted by the OLED device 1' passes through the concave-convex lens structure 2' through multiple reflections, causing the light to propagate at an angle smaller than the critical angle of total internal reflection between the base (such as glass) 3' of the display substrate and air, thereby extracting the light trapped in the display substrate. However, this design still has some light (indicated by the dotted line with an arrow in Figure 1) with an exit angle greater than the critical angle of total internal reflection between the base 3' of the display substrate and air. This part of the light is totally reflected at the interface between the base 3' of the display substrate and air and cannot be extracted, as shown in Figure 1.

[0005] Summary of the Invention

[0006] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0007] An embodiment of the present disclosure provides a display substrate, comprising a display area, wherein the display area comprises a driving structure layer, a flat layer and a light-emitting structure layer stacked in sequence on the substrate in a direction away from the substrate; the driving structure layer comprises a plurality of pixel driving circuits, and the pixel driving circuit comprises a plurality of transistors; in a direction perpendicular to the substrate, the driving structure layer comprises a plurality of conductive structure layers and a plurality of insulating layers, and the conductive structure layers and the insulating layers are alternately arranged in a direction perpendicular to the substrate; the light-emitting structure layer comprises a plurality of light-emitting elements, and a pixel defining layer separating adjacent light-emitting elements, the pixel defining layer is provided with a plurality of pixel openings, and the light-emitting elements are provided at the pixel openings; the area defined by the pixel openings is the light-emitting area, and the area outside the light-emitting area is the non-light-emitting area; in the non-light-emitting area, the flat layer or / and at least one of the insulating layers is provided with a light extraction structure, and the light extraction structure is configured to gather the light emitted by the light-emitting element in a direction perpendicular to the substrate.

[0008] An embodiment of the present disclosure further provides a display device, comprising the display substrate.

[0009] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are intended to provide a further understanding of the technical solutions of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solutions of the present disclosure and do not constitute a limitation of the technical solutions of the present disclosure. The shapes and sizes of the components in the accompanying drawings do not reflect the actual scale and are intended only to illustrate the contents of the present disclosure.

[0011] FIG1 is a schematic diagram of a partial cross-sectional structure of a display substrate in some technologies;

[0012] FIG2 is a schematic diagram of a planar structure of a display substrate according to some exemplary embodiments;

[0013] FIG3 is a schematic diagram of the AA cross-sectional structure of FIG2 in some exemplary embodiments;

[0014] FIG4 is a schematic diagram of the AA cross-sectional structure of FIG2 in some other exemplary embodiments;

[0015] FIG5 is a schematic diagram of the AA cross-sectional structure of FIG2 in some further exemplary embodiments;

[0016] FIG6 is a schematic diagram of the AA cross-sectional structure of FIG2 in some further exemplary embodiments;

[0017] FIG7 is a schematic diagram of the AA cross-sectional structure of FIG2 in some further exemplary embodiments;

[0018] FIG. 8 is a schematic diagram of the AA cross-sectional structure of FIG. 2 in some further exemplary embodiments. DETAILED DESCRIPTION

[0019] Those skilled in the art should understand that the technical solutions of the embodiments of the present disclosure may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and all should be included in the scope of the claims of the present disclosure.

[0020] An embodiment of the present disclosure provides a display substrate, comprising a display area, wherein the display area comprises a driving structure layer, a flat layer and a light-emitting structure layer stacked in sequence on the substrate in a direction away from the substrate; the driving structure layer comprises a plurality of pixel driving circuits, and the pixel driving circuit comprises a plurality of transistors; in a direction perpendicular to the substrate, the driving structure layer comprises a plurality of conductive structure layers and a plurality of insulating layers, and the conductive structure layers and the insulating layers are alternately arranged in a direction perpendicular to the substrate; the light-emitting structure layer comprises a plurality of light-emitting elements, and a pixel defining layer separating adjacent light-emitting elements, the pixel defining layer is provided with a plurality of pixel openings, and the light-emitting elements are provided at the pixel openings; the area defined by the pixel openings is the light-emitting area, and the area outside the light-emitting area is the non-light-emitting area; in the non-light-emitting area, the flat layer or / and at least one of the insulating layers is provided with a light extraction structure, and the light extraction structure is configured to gather the light emitted by the light-emitting element in a direction perpendicular to the substrate.

[0021] The display substrate of the embodiment of the present disclosure can gather the light emitted by the light-emitting element in a direction perpendicular to the substrate by arranging a light extraction structure on the flat layer in the non-luminous area or / and at least one of the insulating layers. In this way, part of the light that was originally unable to be emitted due to total reflection at the interface between the substrate and the air can be taken out, thereby improving the light extraction efficiency. In addition, the large-angle emitted light originally at the interface between the substrate and the air can be gathered in a direction perpendicular to the substrate, thereby playing a focusing role and improving the light leakage phenomenon.

[0022] Figure 2 is a schematic diagram of the planar structure of a display substrate of some exemplary embodiments. As shown in Figure 2, the display substrate includes a display area 100 and a non-display area 200 located outside the display area 100; the display area 100 includes a plurality of pixel units P arranged in an array on a substrate, and the pixel unit P includes a plurality of sub-pixels that emit light of different colors. For example, the pixel unit P may include a first sub-pixel P1 that emits a first color light (such as red light), a second sub-pixel P2 that emits a second color light (such as green light), and a third sub-pixel P3 that emits a third color light (such as blue light). The second sub-pixel P2 that emits the second color light (such as green light) in the pixel unit P can be set to one or two. In other embodiments, the pixel unit may further include a fourth sub-pixel that emits a fourth color light (such as white light or yellow light). The embodiment of the present disclosure does not limit the type, number, and arrangement of the sub-pixels contained in the pixel unit.

[0023] FIG3 is a schematic diagram of the AA cross-sectional structure of FIG2 in some exemplary embodiments. As shown in FIG2 and FIG3, the display substrate includes a display area 100 and a non-display area 200 located outside the display area 100; the display area 100 includes a driving structure layer 20, a planar layer 40, and a light-emitting structure layer 50 sequentially stacked on the substrate 10 in a direction away from the substrate 10;

[0024] The driving structure layer 20 includes a plurality of pixel driving circuits, each of which includes a plurality of transistors 21. In a direction perpendicular to the substrate 10, the driving structure layer 20 includes a plurality of conductive structure layers and a plurality of insulating layers, wherein the conductive structure layers and the insulating layers are alternately arranged in a direction perpendicular to the substrate 10.

[0025] The light-emitting structure layer 50 includes a plurality of light-emitting elements 51 and a pixel defining layer 52 separating adjacent light-emitting elements 51. The pixel defining layer 52 is provided with a plurality of pixel openings 521, and the light-emitting elements 51 are provided at the pixel openings 521. The area defined by the pixel openings 521 is a light-emitting area 101, and the area outside the light-emitting area 101 is a non-light-emitting area 102. The light-emitting elements 51 are connected to the pixel driving circuit and emit light under the drive of the pixel driving circuit. Each sub-pixel includes the light-emitting element 51.

[0026] In the non-luminous area 102, the insulating layer in contact with the flat layer 40 among the multiple insulating layers is provided with a first light extraction structure 71, and the light extraction structure includes the first light extraction structure 71, which is configured to gather the light emitted by the light-emitting element 51 in a direction perpendicular to the substrate 10.

[0027] In some exemplary embodiments, as shown in FIG3 , the multiple conductive structural layers of the driving structure layer 20 may include a first conductive structural layer, a second conductive structural layer, and a third conductive structural layer sequentially arranged in a direction away from the substrate 10; the first conductive structural layer and the third conductive structural layer may be metal layers, the second conductive structural layer may be a semiconductor layer, the first conductive structural layer may include a gate electrode 211 of the transistor 21, the second conductive structural layer may include an active layer 212 of the transistor 21, and the third conductive structural layer may include a source electrode 213 and a drain electrode 214 of the transistor 21. The multiple insulating layers of the driving structure layer 20 may include a first insulating layer 201 located between the first and second conductive structural layers, a second insulating layer 202 located between the second and third conductive structural layers, and a third insulating layer 203 covering the third conductive structural layer.

[0028] The multiple insulating layers of the driving structure layer 20 can all be inorganic insulating layers. Each insulating layer can be made of silicon oxide (SiO X ), silicon nitride (SiN X ) and silicon oxynitride (SiO X N Y ), and may be a single-layer structure or a multi-layer composite structure. The flat layer 40 may be an organic insulating layer, and may be made of a resin material. The conductive structural layer of the metal material of the driving structure layer 20 may be made of any one or more of silver (Ag), copper (Cu), aluminum (Al) and molybdenum (Mo), or an alloy material of the above metals, such as aluminum neodymium alloy (AlNd) or molybdenum niobium alloy (MoNb), and may be a single-layer structure, or a multi-layer composite structure, such as Mo / Cu / Mo. The active layer 212 may be made of amorphous indium gallium zinc oxide (a-IGZO), zinc oxynitride (ZnON), indium zinc tin oxide (IZTO), amorphous silicon (a-Si), polycrystalline silicon (p-Si), sexithiophene, polythiophene and the like, that is, the present disclosure is applicable to transistors manufactured based on oxide technology, silicon technology and organic technology. The substrate 10 may be made of a transparent material such as glass.

[0029] FIG3 only illustrates one film layer structure of the driving structure layer. The transistor 21 in FIG3 is a bottom-gate transistor. The number of conductive structure layers is shown as three, and the number of insulating layers is three. In other embodiments, the transistor 21 may be a top-gate transistor, the number of conductive structure layers in the driving structure layer 20 may be more than three, and the number of insulating layers may be more than three. In addition, the multiple insulating layers of the driving structure layer 20 illustrated in FIG3 include a third insulating layer 203 (an inorganic insulating layer, which may be referred to as a passivation layer) covering the transistor 21, and the flat layer 40 is provided on the surface of the third insulating layer 203 away from the substrate 10. In other embodiments, the insulating layer (an inorganic insulating layer, which may be referred to as a passivation layer) may not be provided on the side of the transistor 21 away from the substrate 10 in the driving structure layer 20, and the flat layer 40 may directly cover the transistor 21. For example, the flat layer 40 may directly cover the surface of the source electrode 213 and the drain electrode 214 of the transistor 21. The pixel driving circuit can be a 3T1C, 4T1C, 5T1C, 5T2C, 6T1C, 7T1C, or 8T1C structure, where T refers to the thin film transistor 21 and C refers to the storage capacitor. The disclosed embodiment does not limit the structure of the pixel driving circuit. In addition, the driving structure layer 20 also includes some signal lines, such as a gate line that provides a scanning signal to the gate electrode 211 of the transistor 21, and a data line that provides a data signal to the source electrode 213 or the drain electrode 214 of the transistor 21.

[0030] In some exemplary embodiments, as shown in FIG3 , the light-emitting element 51 may be an OLED device. The light-emitting element 51 may include a first electrode 511 (e.g., an anode), an organic light-emitting layer 512, and a second electrode (e.g., a cathode) layer 513 stacked in sequence in a direction away from the substrate 10. The first electrode 511 is connected to a pixel driving circuit. The light-emitting element 51 may further include other film layers, such as any one or more film layers of a hole injection layer, a hole transport layer, and an electron blocking layer may be provided between the first electrode 511 and the organic light-emitting layer 512, and any one or more film layers of an electron injection layer, an electron transport layer, and a hole blocking layer may be provided between the second electrode layer 513 and the organic light-emitting layer 512.

[0031] The first electrode 511 can be made of a transparent conductive material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). The second electrode layer 513 can be made of any one or more of magnesium (Mg), silver (Ag), aluminum (Al), copper (Cu), and lithium (Li), or an alloy made of any one or more of the above metals.

[0032] In some exemplary embodiments, as shown in FIG3 , the light-emitting element 51 may be a bottom-emitting OLED device. The display area 100 may further include a color filter layer 30 located between the planar layer 40 and the driving structure layer 20 . The color filter layer 30 includes a plurality of filter units 31 . The orthographic projections of the filter units 31 on the substrate 10 include the orthographic projections of the pixel openings 521 on the substrate 10 .

[0033] The multiple filter units 31 may include multiple filter units that transmit light of different colors (the same filter unit 31 transmits light of the same color), with each filter unit 31 transmitting light of a predetermined color. The color of the light transmitted by the filter unit 31 corresponds to the color of the light emitted by the corresponding sub-pixel. For example, the multiple filter units 31 may include multiple first filter units that transmit light of a first color, multiple second filter units that transmit light of a second color, and multiple third filter units that transmit light of a third color. The first filter units are positioned opposite the pixel opening area of ​​the first sub-pixel, the second filter units are positioned opposite the pixel opening area of ​​the second sub-pixel, and the third filter units are positioned opposite the pixel opening area of ​​the third sub-pixel.

[0034] In some exemplary embodiments, as shown in FIG3 , the display area may further include an encapsulation structure layer 60 disposed on the side of the light-emitting structure layer 50 away from the substrate 10; the encapsulation structure layer 60 may include a first encapsulation layer, a second encapsulation layer, and a third encapsulation layer stacked in sequence in a direction away from the substrate 10, and the materials of the first encapsulation layer and the third encapsulation layer may be inorganic materials, and the material of the second encapsulation layer may be organic materials.

[0035] In some exemplary embodiments, as shown in FIG3 , in the non-luminescent region 102, a first groove 81 is provided on a surface of an insulating layer among the plurality of insulating layers that contacts the planar layer 40 and is away from the substrate 10, and the first light extraction structure 71 is provided in the first groove 81. The shape of the first groove 81 may be the same as that of the first light extraction structure 71.

[0036] Exemplarily, the refractive index of the first light extraction structure 71 is greater than the refractive index of the flat layer 40. Thus, the light emitted by the light-emitting element 51 is refracted when it reaches the interface between the flat layer 40 and the first light extraction structure 71, and the angle of emission of the light becomes smaller, thereby focusing the light in a direction perpendicular to the substrate 10 (the direction of emission of the light is indicated by a dotted line with an arrow in FIG3 ). In this way, part of the light that was originally totally reflected at the interface between the substrate 10 and the air and could not be emitted can be extracted, thereby improving the light extraction efficiency. In addition, the large-angle light originally emitted at the interface between the substrate 10 and the air can be focused in a direction perpendicular to the substrate, thereby achieving a focusing effect and improving light leakage.

[0037] For example, the surface of the first light extraction structure 71 facing the substrate 10 may be a curved surface, such as a hemispherical surface, and the surface of the first light extraction structure 71 facing away from the substrate 10 may be a flat surface. The surface of the first light extraction structure 71 facing the substrate 10 (the interface between the first light extraction structure 71 and the insulating layer) is a hemispherical surface. In this way, light can pass through the center of the hemispherical surface and exit from the surface of the first light extraction structure 71 facing the substrate 10 without changing its exit direction.

[0038] For example, the refractive index of the first light extraction structure 71 may be greater than the refractive index of the planar layer 40 , and may be greater than the refractive index of the insulating layer in contact with the planar layer 40 among the plurality of insulating layers.

[0039] The flat layer 40 may be made of a resin material, and the refractive index of the flat layer 40 may be about 1.5. The first light extraction structure 71 may be made of an acrylic or epoxy resin material with zirconium oxide scattering particles added thereto.

[0040] Exemplarily, the refractive index of the first light extraction structure 71 may be greater than 1.5.

[0041] Exemplarily, a plurality of first light extraction structures 71 may be provided, and the plurality of first light extraction structures 71 may be arranged around the light-emitting area 101. Each light-emitting area 101 may be surrounded by a plurality of first light extraction structures 71. Light emitted by the light-emitting element 51 in the light-emitting area 101 may be focused perpendicularly to the substrate 10 by the plurality of first light extraction structures 71 surrounding the light-emitting area 101. In other embodiments, the light-emitting area 101 may be surrounded by a ring-shaped first light extraction structure 71.

[0042] In some exemplary embodiments, as shown in FIG. 4 , which is a schematic diagram of the AA cross-sectional structure of FIG. 2 in other exemplary embodiments, in the non-luminescent region 102, the insulating layer in contact with the planar layer 40 among the multiple insulating layers is provided with the first light extraction structure 71; in the luminescent region 101, the surface of the insulating layer near the planar layer 40 among the multiple insulating layers, which is away from the substrate 10, may be provided with a third groove 83, and the third light extraction structure 73 is provided within the third groove 83. The light extraction structure includes the first light extraction structure 71 and the third light extraction structure 73. The third light extraction structure 73 is configured to focus light emitted from the light-emitting element 51 in a direction perpendicular to the substrate 10. One or more third light extraction structures 73 may be provided within the luminescent region 101.

[0043] In this embodiment, a first light extraction structure 71 is set in the non-luminous area 102, and a third light extraction structure 73 is set in the luminous area 101. In this way, the emission direction of more outgoing light can be changed, thereby extracting more light that would originally be totally reflected at the interface between the substrate 10 and the air and unable to be emitted, and the light leakage phenomenon can be improved.

[0044] For example, the shape of the third groove 83 can be the same as that of the third light extraction structure 73. The surface of the third light extraction structure 73 facing the substrate 10 can be a hemispherical surface, and the surface of the third light extraction structure 73 facing away from the substrate 10 can be a flat surface. In this way, because the surface of the third light extraction structure 73 facing the substrate 10 (the interface between the third light extraction structure 73 and the insulating layer) is a hemispherical surface, light can pass through the center of the hemispherical surface and exit from the surface of the third light extraction structure 73 facing the substrate 10 without changing its exit direction.

[0045] In some examples of this embodiment, in the light-emitting region 101, the flat layer 40 may be provided on a surface of the third light extraction structure 73 away from the substrate 10. The refractive index of the third light extraction structure 73 may be greater than that of the flat layer 40. In this way, light emitted from the light-emitting element 51 is refracted upon reaching the interface between the flat layer 40 and the third light extraction structure 73, reducing the light's exit angle and thereby converging the light perpendicular to the substrate 10. The refractive index of the third light extraction structure 73 may also be greater than that of the insulating layer.

[0046] In some examples of this embodiment, the display area 100 may further include a color filter layer 30 located between the planar layer 40 and the driving structure layer 20. The color filter layer 30 includes a plurality of filter units 31. The orthographic projections of the filter units 31 on the substrate 10 include the orthographic projections of the pixel openings 521 on the substrate 10. The third light extraction structure 73 may be located on the side of the filter units 31 facing the substrate 10.

[0047] The filter unit 31 can be disposed on a surface of the third light extraction structure 73 that is distal from the substrate 10. The refractive index of the third light extraction structure 73 can be greater than that of the filter unit 31. In this way, light emitted from the light-emitting element 51 is refracted upon reaching the interface between the filter unit 31 and the third light extraction structure 73, reducing the light's exit angle and thereby converging the light perpendicular to the substrate 10 (the light's exit direction is indicated by the dotted arrow in FIG4 ). The refractive index of the third light extraction structure 73 can also be greater than that of the insulating layer.

[0048] In some examples of this embodiment, the refractive index of the third light extraction structure 73 may be greater than 1.5.

[0049] In some exemplary embodiments, using the display substrate illustrated in FIG. 3 as an example, the process for preparing the display substrate may include the following steps: forming a transistor 21 and a signal line on a substrate 10; then, forming an inorganic insulating film (a third insulating film) covering the transistor 21; then, using a photolithography process, forming the first groove 81 in the third insulating film at a position corresponding to the non-luminescent region 102, thereby forming the third insulating layer 203; then, filling the first groove 81 with a material having a higher refractive index (which may be an acrylic or epoxy resin material with added zirconium oxide scattering particles) to form the first light extraction structure 71; then, sequentially forming film layers such as the color filter layer 30, the planarization layer 40, the first electrode 511, the pixel defining layer 52, the organic light-emitting layer 512, the second electrode layer 513, and the encapsulation structure layer 60. In this embodiment, the method for manufacturing the first light extraction structure 71 is simple and facilitates mass production of display substrates.

[0050] In some exemplary embodiments, as shown in FIG5 , which is a schematic diagram of the AA cross-sectional structure of FIG2 in still other exemplary embodiments, the display area 100 includes a driving structure layer 20 , a planar layer 40 , and a light-emitting structure layer 50 sequentially stacked on the substrate 10 in a direction away from the substrate 10 ;

[0051] The driving structure layer 20 includes a plurality of pixel driving circuits, each of which includes a plurality of transistors 21. In a direction perpendicular to the substrate 10, the driving structure layer 20 includes a plurality of conductive structure layers and a plurality of insulating layers, wherein the conductive structure layers and the insulating layers are alternately arranged in a direction perpendicular to the substrate 10.

[0052] The light-emitting structure layer 50 includes a plurality of light-emitting elements 51 and a pixel defining layer 52 separating adjacent light-emitting elements 51. The pixel defining layer 52 has a plurality of pixel openings 521, and the light-emitting elements 51 are disposed at the pixel openings 521. The area defined by the pixel openings 521 is a light-emitting area 101, and the area outside the light-emitting area 101 is a non-light-emitting area 102.

[0053] In the non-luminescent area 102 , the flat layer 40 is provided with a second light extraction structure 72 . The light extraction structure includes the second light extraction structure 72 , and the second light extraction structure 72 is configured to focus the light emitted by the light emitting element 51 in a direction perpendicular to the substrate 10 .

[0054] 5 , a second groove 82 may be provided on a surface of the planar layer 40 away from the substrate 10 , and the second light extraction structure 72 may be provided in the second groove 82 . The shape of the second groove 82 may be the same as that of the second light extraction structure 72 .

[0055] Exemplarily, the refractive index of the second light extraction structure 72 can be less than the refractive index of the flat layer 40, and the second light extraction structure 72 is configured to cause the light emitted by the light emitting element 51 to be totally reflected at the interface between the flat layer 40 and the second light extraction structure 72. In this way, when the outgoing light at a large angle is incident from the flat layer 40 to the surface of the second light extraction structure 72, total reflection will occur, changing the outgoing angle of the light (the outgoing angle becomes smaller), which can reduce the incident angle of the outgoing light at the interface between the substrate 10 and the air, thereby extracting the light that would have been totally reflected at the interface between the substrate 10 and the air and could not be emitted, thereby improving the light extraction efficiency (the outgoing direction of the light is indicated by the dotted line with an arrow in FIG5 ). In addition, the large-angle outgoing light originally at the interface between the substrate 10 and the air can be gathered in a direction perpendicular to the substrate, which plays a focusing role and can improve the light leakage phenomenon.

[0056] The material of the flat layer 40 may be resin, and the refractive index of the flat layer 40 may be about 1.5. The refractive index of the second light extraction structure 72 may be about 1.4, and may be made of silicone material.

[0057] Alternatively, the material of the second light extraction structure 72 can be a high-reflectivity material, such as silver, aluminum, etc. The reflectivity of the second light extraction structure 72 can be greater than 80%. In this way, light incident on the surface of the second light extraction structure 72 will be reflected on the surface of the second light extraction structure 72, changing the light's exit angle (decreasing the exit angle), thereby reducing the incident angle of the exiting light at the interface between the substrate 10 and the air, thereby extracting light that would otherwise be totally reflected at the interface between the substrate 10 and the air and unable to exit, thereby improving light extraction efficiency.

[0058] Exemplarily, the surface of the second light extraction structure 72 facing the substrate 10 may be a hemispherical surface or a semi-ellipsoidal surface (a hemispherical surface is shown in FIG5 ), and the surface of the second light extraction structure 72 away from the substrate 10 may be a plane.

[0059] Exemplarily, a plurality of second light extraction structures 72 may be provided, and the plurality of second light extraction structures 72 may be arranged around the light-emitting area 101. In this way, the light emitted by the light-emitting elements 51 in the light-emitting area 101 can be focused in a direction perpendicular to the substrate 10 by the plurality of second light extraction structures 72 surrounding the light-emitting area 101. In other embodiments, the light-emitting area may be surrounded by a ring-shaped second light extraction structure.

[0060] In some exemplary embodiments, as shown in Figure 6, Figure 6 is a schematic diagram of the AA cross-sectional structure of Figure 2 in some further exemplary embodiments. In the non-luminous area 102, the flat layer 40 and at least one of the insulating layers are provided with a second light extraction structure 72, and the light extraction structure includes a second light extraction structure 72, and the second light extraction structure 72 is configured to gather the light emitted by the light-emitting element 51 in a direction perpendicular to the substrate 10.

[0061] For example, the planar layer 40 may be provided with an opening 91 penetrating the planar layer 40 , and the second light extraction structure 72 is provided in the opening 91 . The shape of the opening 91 and the shape of the second light extraction structure 72 may be the same.

[0062] The opening 91 can extend into the insulating layer, that is, the opening 91 can be provided in the planar layer 40 and at least one of the insulating layers. Accordingly, the second light extraction structure 72 can extend into the insulating layer and be provided in the planar layer 40 and at least one of the insulating layers. This increases the size of the second light extraction structure 72 perpendicular to the substrate 10, allowing more outgoing light to enter the surface of the second light extraction structure 72, thereby enhancing the light extraction effect.

[0063] For example, the surface of the second light extraction structure 72 facing the light-emitting area 101 may be an inclined surface or a curved surface. For example, the surface of the second light extraction structure 72 facing the substrate 10 may be a hemispherical surface or a hemispherical surface (a hemispherical surface is shown in FIG6 ), and the surface of the second light extraction structure 72 facing away from the substrate 10 may be a flat surface.

[0064] For example, the refractive index of the second light extraction structure 72 can be lower than that of the flat layer 40 and lower than that of the insulating layer. The second light extraction structure 72 is configured to cause light emitted from the light-emitting element 51 to undergo total internal reflection at the surface of the second light extraction structure 72. Thus, when light emitted at a large angle strikes the surface of the second light extraction structure 72, total internal reflection occurs, changing the light's exit angle (decreasing the exit angle), thereby reducing the incident angle of the light at the interface between the substrate 10 and the air. This allows light that would otherwise be totally reflected at the interface between the substrate 10 and the air and therefore be prevented from exiting to be extracted, thereby improving light extraction efficiency (the exit direction of the light is indicated by the dotted arrow line in FIG6 ).

[0065] The material of the flat layer 40 can be resin, and the refractive index of the flat layer 40 can be about 1.5. The refractive index of the second light extraction structure 72 can be less than 1.5. For example, the refractive index of the second light extraction structure 72 can be about 1.4, and silicone materials can be used.

[0066] Alternatively, the material of the second light extraction structure 72 can be a high-reflectivity material, such as silver, aluminum, etc. The reflectivity of the second light extraction structure 72 can be greater than 80%. In this way, light incident on the surface of the second light extraction structure 72 will be reflected on the surface of the second light extraction structure 72, changing the light's exit angle (decreasing the exit angle), thereby reducing the incident angle of the exiting light at the interface between the substrate 10 and the air. This can extract light that would otherwise be totally reflected at the interface between the substrate 10 and the air and unable to exit, thereby improving light extraction efficiency.

[0067] In some exemplary embodiments, as shown in Figure 7, Figure 7 is a schematic diagram of the AA cross-sectional structure of Figure 2 in some further exemplary embodiments. In the non-luminous area 102, the flat layer 40 and at least one of the insulating layers are provided with a second light extraction structure 72, and the light extraction structure includes a second light extraction structure 72, and the second light extraction structure 72 is configured to gather the light emitted by the light-emitting element 51 in a direction perpendicular to the substrate 10.

[0068] In the non-luminescent area 102, the planar layer 40 may be provided with an opening 91 penetrating the planar layer 40, and the second light extraction structure 72 is provided in the opening 91. The shape of the opening 91 and the shape of the second light extraction structure 72 may be the same.

[0069] The opening 91 can extend into the insulating layer; that is, the opening 91 can be provided within the planar layer 40 and at least one of the insulating layers. Accordingly, the second light extraction structure 72 can extend into the insulating layer and be provided within the planar layer 40 and at least one of the insulating layers. This increases the size of the second light extraction structure 72 perpendicular to the substrate 10, allowing more outgoing light to enter the surface of the second light extraction structure 72 and enhancing the light extraction effect.

[0070] Exemplarily, the surface of the second light extraction structure 72 facing the light emitting area 101 may be a slope or a curved surface (a slope in the example of FIG7 ). For example, the cross-sectional shape of the second light extraction structure 72 in the direction perpendicular to the substrate 10 may be an inverted trapezoid, and the orthographic projection of the surface of the second light extraction structure 72 away from the substrate 10 on the substrate 10 includes the orthographic projection of the surface of the second light extraction structure 72 close to the substrate 10 on the substrate 10. In the direction parallel to the substrate 10, the edge of the surface of the second light extraction structure 72 away from the substrate 10 is arranged closer to the light emitting area 101 than the edge of the surface of the second light extraction structure 72 close to the substrate 10. The light extraction effect can be optimized by optimizing the angle of the waist of the inverted trapezoid (the direction of light emission is indicated by the dotted line with an arrow in FIG7 ).

[0071] In some exemplary embodiments, as shown in FIG8 , which is a schematic diagram of the AA cross-sectional structure of FIG2 in still other exemplary embodiments, at least one of the light-emitting areas 101 is a reference light-emitting area 101R. In the non-light-emitting area 102 surrounding the reference light-emitting area 101R, a second groove 82 is provided on a surface of the planar layer 40 away from the substrate 10. The planar layer 40 is further provided with an opening 91 that passes through the planar layer 40 (the opening 91 may extend to the insulating layer). A second light extraction structure 72 is provided both within the second groove 82 and within the opening 91. The light extraction structure includes the second light extraction structure 72.

[0072] The second groove 82 is positioned closer to the reference light-emitting area 101R than the opening 91. In a direction perpendicular to the substrate 10, the size of the second light extraction structure 72 within the opening 91 is larger than the size of the second light extraction structure 72 within the second groove 82. Light emitted from the light-emitting element 51 in the reference light-emitting area 101R is reflected successively by the second light extraction structure 72 within the second groove 82 and the second light extraction structure 72 within the opening 91 before being emitted from the substrate 10. In this way, after multiple reflections, the incident angle of the light emitted from the light-emitting element 51 in the reference light-emitting area 101R at the interface between the substrate 10 and the air can be reduced, thereby extracting light that would otherwise be totally reflected at the interface between the substrate 10 and the air and unable to escape, thereby improving light extraction efficiency (the direction of light emission is indicated by the dotted arrow in FIG8 ).

[0073] Exemplarily, the shape of the opening 91 may be the same as the shape of the second light extraction structure 72 in the opening 91, and the shape of the second groove 82 may be the same as the shape of the second light extraction structure 72 in the second groove 82. The surface of the second light extraction structure 72 in the second groove 82 facing the substrate 10 may be a hemispherical surface, and the surface away from the substrate 10 may be a plane. The surface of the second light extraction structure 72 in the opening 91 facing the substrate 10 may be a semi-ellipsoidal surface, and the surface away from the substrate 10 may be a plane. Alternatively, the cross-sectional shape of the second light extraction structure 72 in the opening 91 in a direction perpendicular to the substrate 10 may be an inverted trapezoid. The shape of the second light extraction structure 72 in the second groove 82 may be the same as or different from the second light extraction structure 72 in the opening 91.

[0074] Exemplarily, the refractive index of the second light extraction structure 72 in the second groove 82 can be smaller than the refractive index of the flat layer 40, and the refractive index of the second light extraction structure 72 in the opening 91 can be smaller than the refractive index of the flat layer 40 and can be smaller than the refractive index of the insulating layer.

[0075] In some exemplary embodiments, as shown in the examples of Figures 5 to 8 , during the preparation of the display substrate, after forming a flat film (which may be a resin material), a photolithography process may be used to form a concave-convex lens structure at a position of the flat film corresponding to the light-emitting region 101, and to form the second grooves 82 and / or openings 91 at a position of the flat film corresponding to the non-light-emitting region 102, thereby forming the flat layer 40. Subsequently, the second grooves 82 and / or openings 91 of the flat layer 40 in the non-light-emitting region 102 are filled with a material with a lower refractive index (which may be a silicone material) or a high reflectivity material to form the second light extraction structure 72. Subsequently, the first electrode 511, pixel defining layer 52, organic light-emitting layer 512, second electrode layer 513, and encapsulation structure layer 60 are sequentially fabricated. In this embodiment, the method for fabricating the second light extraction structure 72 is simple and facilitates mass production of display substrates.

[0076] The present disclosure also provides a display device comprising the display substrate described in any of the above embodiments. The display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigation system.

[0077] In the drawings, the sizes of components, layer thicknesses, or regions are sometimes exaggerated for clarity. Therefore, the embodiments of the present disclosure are not necessarily limited to these dimensions, and the shapes and sizes of each component in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate some examples, and the embodiments of the present disclosure are not limited to the shapes or values ​​shown in the drawings.

[0078] In this description, "parallel" refers to a state where the angle formed by two straight lines is greater than -10° and less than 10°, and thus includes a state where the angle is greater than -5° and less than 5°. Furthermore, "perpendicular" refers to a state where the angle formed by two straight lines is greater than 80° and less than 100°, and thus includes a state where the angle is greater than 85° and less than 95°.

[0079] In the description herein, the terms "upper", "lower", "left", "right", "top", "inner", "outer", "axial", "four corners", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are merely simplified descriptions for the convenience of describing the embodiments of the present disclosure, and do not indicate or imply that the structure referred to has a specific orientation, is constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present disclosure.

[0080] In the description herein, unless otherwise expressly specified or limited, the terms "connect," "fixed connection," "installation," and "assembly" should be understood in a broad sense, for example, to mean a fixed connection, a detachable connection, or an integral connection; the terms "installation," "connection," and "fixed connection" can mean a direct connection, an indirect connection through an intermediate medium, or internal communication between two components. A person of ordinary skill in the art can understand the meaning of the above terms in the embodiments of the present disclosure according to the circumstances.

Claims

1. A display substrate, comprising a display area, wherein the display area comprises a driving structure layer, a flat layer and a light emitting structure layer sequentially stacked on a substrate in a direction away from the substrate; The driving structure layer includes a plurality of pixel driving circuits, and the pixel driving circuits include a plurality of transistors; in a direction perpendicular to the substrate, the driving structure layer includes a plurality of conductive structure layers and a plurality of insulating layers, and the conductive structure layers and the insulating layers are alternately arranged in a direction perpendicular to the substrate; The light emitting structure layer includes a plurality of light emitting elements and a pixel defining layer separating adjacent light emitting elements, the pixel defining layer is provided with a plurality of pixel openings, the light emitting elements are provided at the pixel openings; the area defined by the pixel openings is a light emitting area, and the area outside the light emitting area is a non-light emitting area; In the non-luminescent area, the planar layer and / or at least one of the insulating layers is provided with a light extraction structure, and the light extraction structure is configured to gather the light emitted by the light emitting element in a direction perpendicular to the substrate.

2. The display substrate according to claim 1, wherein: A first groove is provided on a surface of an insulating layer in contact with the flat layer among the plurality of insulating layers and away from the substrate, and the light extraction structure includes a first light extraction structure, which is provided in the first groove.

3. The display substrate according to claim 2, wherein: The refractive index of the first light extraction structure is greater than the refractive index of the flat layer.

4. The display substrate according to claim 1, wherein: A second groove is provided on a surface of the flat layer away from the substrate, the light extraction structure includes a second light extraction structure, and the second light extraction structure is provided in the second groove.

5. The display substrate according to claim 1, wherein: The flat layer is provided with an opening that penetrates the flat layer and extends into the insulating layer. The light extraction structure includes a second light extraction structure. The second light extraction structure is provided in the opening.

6. The display substrate according to claim 4 or 5, wherein: The refractive index of the second light extraction structure is smaller than that of the flat layer, and the second light extraction structure is configured to cause the light emitted by the light emitting element to be totally reflected on the surface of the second light extraction structure; or, the reflectivity of the second light extraction structure is greater than 80%.

7. The display substrate according to claim 6, wherein: The refractive index of the second light extraction structure is also smaller than the refractive index of the insulating layer.

8. The display substrate according to claim 1, wherein: At least one of the light-emitting areas is a reference light-emitting area, and in the non-light-emitting area surrounding the reference light-emitting area, a second groove is provided on the surface of the flat layer away from the substrate, and the flat layer is further provided with an opening penetrating the flat layer, and the light extraction structure is provided in both the second groove and the opening; The second groove is arranged closer to the reference light-emitting area than the opening, and in the direction perpendicular to the substrate, the size of the light extraction structure in the opening is larger than the size of the light extraction structure in the second groove; the light emitted by the light-emitting element in the reference light-emitting area is reflected by the light extraction structure in the second groove and the light extraction structure in the opening in succession, and then emitted from the substrate.

9. The display substrate according to claim 1, wherein: The surface of the light extraction structure facing the substrate is a curved surface, and the surface of the light extraction structure away from the substrate is a flat surface; or, the surface of the light extraction structure facing the light emitting area is an inclined surface or a curved surface.

10. The display substrate according to claim 1, wherein: The light extraction structure is provided in plurality, and the plurality of light extraction structures are arranged around the light emitting area.

11. The display substrate according to claim 1, wherein: In the light-emitting area, a third groove is provided on the surface of the insulating layer close to the flat layer and away from the substrate, and the light extraction structure includes a third light extraction structure, and the third light extraction structure is provided in the third groove, and the third light extraction structure is configured to gather the light emitted by the light-emitting element in a direction perpendicular to the substrate.

12. The display substrate according to claim 2, wherein: The refractive index of the first light extraction structure is greater than 1.

5.

13. The display substrate according to claim 4 or 5, wherein: The refractive index of the second light extraction structure is less than 1.5, or the reflectivity of the second light extraction structure is greater than 80%.

14. The display substrate according to claim 1, wherein: The display area further includes a color filter layer located between the planar layer and the driving structure layer, the color filter layer includes a plurality of filter units, and the orthographic projection of the filter unit on the substrate includes the orthographic projection of the pixel opening on the substrate.

15. A display device comprising the display substrate according to any one of claims 1 to 14.

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