Display substrate and display device

Abstract

The invention discloses a display substrate and a display device. The display substrate comprises: a substrate; the light-emitting element is located on the substrate and comprises a first electrode, a second electrode and a light-emitting functional layer located between the first electrode and the second electrode; a pixel defining layer including a pixel defining portion and an opening configured to expose at least a portion of the first electrode; the filling layer is positioned on one side, deviating from the substrate, of the second electrode; the pixel limiting part comprises a light extraction structure, and the refractive index of the filling layer is larger than that of the light extraction structure. According to the display substrate, forward light emitting can be enhanced, the light extraction effect is enhanced, and the lighting effect is improved.

Description

Display substrate and display device Technical Field

[0001] Embodiments of the present disclosure relate to a display substrate and a display device. Background Art

[0002] Organic electroluminescent devices, such as organic light-emitting diode (OLED) display devices, have advantages over liquid crystal display (LCD) devices, such as self-luminescence, fast response, wide viewing angle, high brightness, bright colors, light weight, and thin thickness, and are considered to be the next generation display technology.

[0003] Summary of the Invention

[0004] The embodiments of the present disclosure provide a display substrate and a display device to enhance forward light emission, improve light extraction effect, and improve light efficiency.

[0005] An embodiment of the present disclosure provides a display substrate, comprising: a base substrate; a light-emitting element located on the base substrate, comprising a first electrode, a second electrode, and a light-emitting functional layer located between the first electrode and the second electrode; a pixel defining layer, comprising a pixel defining portion and an opening, wherein the opening is configured to expose at least a portion of the first electrode; and a filling layer, located on a side of the second electrode facing away from the base substrate; the pixel defining portion comprises a light extraction structure, and the refractive index of the filling layer is greater than the refractive index of the light extraction structure.

[0006] For example, the side surface of the light extraction structure is a total reflection interface.

[0007] For example, the pixel defining portion further includes a body, and a refractive index of the body is different from a refractive index of the light extraction structure.

[0008] For example, the light extraction structure is at least located on a side surface of the main body.

[0009] For example, the main body is located at least on a side surface of the light extraction structure.

[0010] For example, the light extraction structure includes a conductive reflective layer.

[0011] For example, the display substrate further includes a first conductive element, and the second electrode is connected to the first conductive element through the light extraction structure.

[0012] For example, the first conductive element and the first electrode are located in the same layer.

[0013] For example, the display substrate further includes a second conductive element, and the first conductive element is connected to the second conductive element.

[0014] For example, the display substrate further includes a pixel circuit, the first electrode is connected to the pixel circuit, the pixel circuit is configured to drive the light emitting element, and the second conductive element is insulated from the pixel circuit.

[0015] For example, the area of ​​the surface of the light extraction structure facing away from the base substrate is smaller than the area of ​​the surface of the light extraction structure close to the base substrate, and the area of ​​one end of the opening facing away from the base substrate is larger than the area of ​​one end of the opening close to the base substrate.

[0016] For example, the main body is located on a side of the light extraction structure facing away from the base substrate.

[0017] For example, the maximum thickness of the main body is smaller than the maximum thickness of the light extraction structure.

[0018] For example, the maximum dimension of the portion of the filling layer located in the opening in a direction perpendicular to the main surface of the base substrate is greater than or equal to the minimum dimension of the light emitting element in a direction perpendicular to the main surface of the base substrate.

[0019] For example, the maximum dimension of the portion of the filling layer located in the opening in a direction perpendicular to the main surface of the base substrate is greater than or equal to 1.2 times the minimum dimension of the light emitting element in a direction perpendicular to the main surface of the base substrate.

[0020] For example, a difference between a refractive index of the filling layer and a refractive index of the light extraction structure is greater than or equal to 0.2.

[0021] For example, the refractive index of the filling layer is greater than or equal to 1.7, and the refractive index of the light extraction structure is less than or equal to 1.5.

[0022] For example, the display substrate further includes an encapsulation layer, wherein the encapsulation layer is configured to encapsulate the light-emitting element, and the encapsulation layer is located on a side of the filling layer away from the base substrate.

[0023] An embodiment of the present disclosure further provides a display device, comprising any of the above-mentioned display substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0025] FIG1 is a plan view of a display substrate provided by an embodiment of the present disclosure.

[0026] 2 to 7 are cross-sectional views of display substrates of several different structures provided by some embodiments of the present disclosure.

[0027] FIG8 is a plan view of a display substrate provided by one embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0029] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0030] Film formation methods for light-emitting elements such as OLEDs primarily include evaporation and solution processes. Evaporation is a mature process for small-scale displays and is currently in mass production. In solution processes, OLED film formation methods primarily include inkjet printing, nozzle coating, spin coating, and screen printing. Inkjet printing, due to its high material utilization and ability to scale up, is considered a key method for mass production of large-scale OLED displays.

[0031] When a light-emitting element, such as an OLED, emits light from its light-exiting side, some light with a large incident angle is reflected back into the display device, preventing it from exiting. Therefore, a light extraction layer can be added to the exterior of the light-exiting side of the light-emitting element to redirect the light and reduce the amount of light trapped within the OLED display device.

[0032] An embodiment of the present disclosure provides a display substrate, which enhances forward light emission, improves light extraction effect, and improves light efficiency by adjusting the structure of a pixel defining layer.

[0033] FIG1 is a plan view of a display substrate provided by an embodiment of the present disclosure. As shown in FIG1 , the display substrate includes a plurality of sub-pixels 100. FIG1 illustrates an example in which a plurality of sub-pixels 100 are arranged in an array. Of course, the arrangement of the plurality of sub-pixels 100 is not limited to that shown in the figure. The shape and size of the sub-pixel 100 are also not limited to those shown in the figure. For example, the sub-pixel 100 can emit red, green, blue or white light as needed, and of course, it can also emit light of other colors depending on the situation. FIG1 illustrates the sub-pixel 100 by its light-emitting area. The sub-pixel 100 shown in FIG1 is the light-emitting area of ​​the light-emitting element.

[0034] FIG1 also shows a light-emitting region R1 and a non-light-emitting region R2. The non-light-emitting region R2 is located between adjacent light-emitting regions R1. As shown in FIG1 , the light-emitting region R1 corresponds to the opening OPN of the pixel-defining layer PDL, while the non-light-emitting region R2 corresponds to the area of ​​the pixel-defining layer PDL excluding the opening OPN.

[0035] Figures 2 to 7 are cross-sectional views of display substrates of different structures provided by some embodiments of the present disclosure. Figure 8 is a plan view of a display substrate provided by one embodiment of the present disclosure.

[0036] As shown in Figures 1 to 7, embodiments of the present disclosure provide a display substrate including a pixel defining layer (PDL) having a pixel defining portion (P0) and an opening (OPN) configured to expose at least a portion of the first electrode (E1). For example, as shown in Figure 1, the opening (OPN) corresponds to the light-emitting region (R1).

[0037] For example, the non-luminescent region R2 corresponds to the pixel defining portion P0, but is not limited thereto. For example, the non-luminescent region R2 corresponds to the top surface of the pixel defining portion P0, and the luminescent region R1 corresponds to the top surface of the opening OPN, but is not limited thereto. For example, in the embodiments of the present disclosure, both the luminescent region R1 and the non-luminescent region R2 are defined by the pixel defining layer PDL.

[0038] As shown in FIG. 2 to FIG. 7 , the opening OPN is defined by the pixel defining portion P0 , and the opening OPN is a through hole in the pixel defining layer PDL.

[0039] As shown in Figures 5 to 7 , embodiments of the present disclosure provide a display substrate comprising a base substrate BS, with a light-emitting element EME disposed on the base substrate BS. The light-emitting element EME comprises a first electrode E1, a second electrode E2, and a light-emitting functional layer EL disposed between the first and second electrodes E1 and E2. Figures 2 to 4 omit structures below the first electrode E1, such as the base substrate and pixel circuitry. The display substrates shown in Figures 2 and 4 may also be supplemented with the base substrate and pixel circuitry shown in Figures 6 and 7 .

[0040] For example, the light emitting element EME includes an OLED, but is not limited thereto.

[0041] As shown in Figures 2 to 7 , the display substrate provided in the embodiment of the present disclosure further includes a filling layer 12 , which is located on the side of the second electrode E2 facing away from the base substrate BS. That is, the filling layer 12 is formed after the second electrode E2 is formed.

[0042] As shown in FIG. 2 to FIG. 7 , in the display substrate provided by the embodiment of the present disclosure, the pixel defining portion P0 includes a light extraction structure 11 , and the refractive index of the filling layer 12 is greater than the refractive index of the light extraction structure 11 .

[0043] In the display substrate provided by the embodiment of the present disclosure, the pixel defining portion P0 has a light extraction structure 11, and the light emitted by the light-emitting element EME is irradiated to the light extraction structure 11 through the filling layer 12. Since the refractive index of the filling layer 12 is greater than the refractive index of the light extraction structure 11, a total reflection interface can be formed on the surface of the light extraction structure 11 to direct the light irradiated on the light extraction structure 11 toward the light emitting side of the display substrate, thereby extracting more light, enhancing the forward light output, enhancing the light extraction effect, improving the light efficiency, and improving the display effect.

[0044] The display substrate provided by the embodiments of the present disclosure simplifies the manufacturing process and is easy to mass produce.

[0045] 2 to 7 show light L, which is emitted by the light emitting element EME and irradiated to the light extraction structure 11 through the filling layer 12 and then emitted from the light emitting side. The upper side of the display substrate in FIG2 to 7 is the light emitting side.

[0046] The material of the light extraction structure 11 is different from the material of the filling layer 12 . The refractive index of the filling layer 12 is different from the refractive index of the light extraction structure 11 .

[0047] 2 to 7 , the side surfaces of the light extraction structure 11 are total reflection interfaces. That is, light emitted by the light emitting element EME and irradiated onto the side surfaces of the light extraction structure 11 can be utilized by total reflection.

[0048] For example, to achieve better light extraction effect, the difference between the refractive index of the filling layer 12 and the refractive index of the light extraction structure 11 is greater than or equal to 0.2. In other embodiments, the difference between the refractive index of the filling layer 12 and the refractive index of the light extraction structure 11 is greater than or equal to 0.3.

[0049] 2 to 7 , the pixel defining portion P0 further includes a body MP having a different refractive index from that of the light extraction structure 11. For example, the body MP is made of a different material from that of the light extraction structure 11.

[0050] For example, as shown in Figures 2, 6, and 7, the light extraction structure 11 is located at least on the side of the main body MP. In some embodiments, the main body MP can be formed first, followed by the light extraction structure 11 located on the side of the main body MP. Figures 2, 6, and 7 illustrate the example of an orthographic projection of the main body MP on the base substrate overlapping with the orthographic projection of the first electrode E1 on the base substrate. In other embodiments, the main body MP can be located between adjacent first electrodes E1, and the orthographic projection of the main body MP on the base substrate does not overlap with the orthographic projection of the first electrode E1 on the base substrate.

[0051] As shown in FIG. 2 , FIG. 6 and FIG. 7 , the interface between the light extraction structure 11 and the second electrode E2 is a total reflection interface.

[0052] 3 , the main body MP is at least located on the side of the light extraction structure 11. In some embodiments, the light extraction structure 11 may be formed first, and then the main body MP located on the side of the light extraction structure 11 may be formed.

[0053] As shown in FIG. 3 , the interface between the light extraction structure 11 and the main body MP is a total reflection interface.

[0054] As shown in Figure 4 , the body MP is located on the side of the light extraction structure 11 that is away from the base substrate BS. That is, the body MP is located above the light extraction structure 11. As shown in Figure 4 , the interface between the light extraction structure 11 and the second electrode E2 is a total reflection interface.

[0055] As shown in FIG4 , the maximum dimension H1 of the light extraction structure 11 in a direction perpendicular to the main surface of the base substrate BS (direction Z) is greater than the maximum dimension H2 of the main body MP in a direction perpendicular to the main surface of the base substrate BS (direction Z). In other words, the maximum thickness of the main body MP is less than the maximum thickness of the light extraction structure 11.

[0056] In some figures of the embodiments of the present disclosure, the plan views show directions X and Y, and the cross-sectional views show direction Z. Directions X and Y are both directions parallel to the main surface of the substrate BS. Direction Z is a direction perpendicular to the main surface of the substrate BS. For example, directions X and Y intersect. The embodiments of the present disclosure are described using the example where directions X and Y are perpendicular. For example, the main surface of the substrate BS is the surface of the substrate BS used to manufacture various components. In the cross-sectional view, the upper surface of the substrate BS is the main surface of the substrate BS. Direction Z is perpendicular to direction X and to direction Y.

[0057] As shown in FIG2 to FIG7 , the main body MP can be made of a liquid-repellent material. For example, the main body MP is made of a fluorine-containing material. For example, the fluorine-containing material includes at least one of fluorine-containing polyimide and fluorine-containing acrylic, but is not limited thereto.

[0058] Of course, the material of the main MP is not limited to lyophobic materials. The main MP can also be made of hydrophilic materials and lyophobic materials, for example, including a hydrophilic layer and a lyophobic layer. For example, the hydrophilic material includes at least one of polyimide and acrylic, but is not limited thereto.

[0059] For example, as shown in Figure 5 , the light extraction structure 11 is a conductive reflective layer that reflects light. For example, as shown in Figure 5 , the material of the light extraction structure 11 includes, but is not limited to, metal. For example, the metal includes, but is not limited to, silver (Ag). The main body MP is located outside the light extraction structure 11 and contacts the side surfaces of the light extraction structure 11. As shown in Figure 5 , the interface between the light extraction structure 11 and the main body MP is a total internal reflection interface.

[0060] For example, as shown in FIG. 5 , the display substrate further includes a first conductive element CEa, and the second electrode E2 is connected to the first conductive element CEa through the light extraction structure 11 .

[0061] For example, as shown in Fig. 5 , the first conductive element CEa and the first electrode E1 are located in the same layer. The first conductive element CEa and the first electrode E1 are formed from the same film layer using the same patterning process.

[0062] For example, as shown in FIG. 5 , the display substrate further includes a second conductive element CEb, and the first conductive element CEa is connected to the second conductive element CEb.

[0063] For example, as shown in FIG5 , the display substrate further includes a pixel circuit 13, the first electrode E1 is connected to the pixel circuit 13, the pixel circuit 13 is configured to drive the light-emitting element EME, and the second conductive element CEb is insulated from the pixel circuit 13. FIG5 schematically illustrates the pixel circuit 13, and the second conductive element CEb may be located on the same layer as the conductive components in the pixel circuit 13. The second conductive element CEb is spaced apart from the conductive components located on the same layer, and the two are insulated from each other.

[0064] Some embodiments of the present disclosure provide a display substrate in which a conductive reflective layer is used as a light extraction structure 11 to enhance forward light extraction, enhance the light extraction effect, and improve the light efficiency. The light extraction structure 11 is used as a connecting element to connect the second electrode E2 to the first conductive element CEa / the second conductive element CEb to reduce resistance, thereby reducing voltage drop and improving the display effect.

[0065] As shown in Figures 5 to 7, the first electrode E1 is connected to the pixel circuit 13. The pixel circuit 13 may include a transistor (T) and a storage capacitor (Cs), but is not limited thereto. For example, the pixel circuit 13 includes a 3T1C, 5T1C, 5T2C, 7T1C, or 7T2C pixel circuit, but is not limited thereto. The number of transistors and storage capacitors included in the pixel circuit 13 can be determined as needed.

[0066] As shown in FIG. 5 to FIG. 7 , the display substrate further includes an insulating layer 14 . The first electrode E1 is located on the insulating layer 14 and is connected to the pixel circuit 13 through a via hole penetrating the insulating layer 14 .

[0067] As shown in FIG. 7 , the first conductive element CEa is located on the insulating layer 14 and is connected to the second conductive element CEb via a via hole penetrating the insulating layer 14 .

[0068] For example, as shown in Figures 2 to 7, the area of ​​the surface of the light extraction structure 11 facing away from the base substrate BS is less than or equal to the area of ​​the surface of the light extraction structure 11 close to the base substrate BS, and the area of ​​one end of the opening OPN facing away from the base substrate BS is greater than the area of ​​the one end of the opening OPN close to the base substrate BS. Figures 2, 6, and 7 illustrate that the area of ​​the surface of the light extraction structure 11 facing away from the base substrate BS is equal to the area of ​​the surface of the light extraction structure 11 close to the base substrate BS. Figures 3 to 5 illustrate that the area of ​​the surface of the light extraction structure 11 facing away from the base substrate BS is less than the area of ​​the surface of the light extraction structure 11 close to the base substrate BS.

[0069] For example, as shown in Figures 2 to 7 , to better achieve total internal reflection and enhance light extraction, the maximum dimension H4 of the portion of the filling layer 12 located within the opening OPN in a direction perpendicular to the main surface of the base substrate BS is greater than or equal to the minimum dimension H5 of the light-emitting element EME in a direction perpendicular to the main surface of the base substrate BS. Of course, in other embodiments, the maximum dimension H4 may also be smaller than the minimum dimension H5. In this case, the minimum dimension H5 may be 1.3-1.5 times the maximum dimension H4.

[0070] For example, as shown in Figures 2 to 7 , the maximum dimension H4 of the portion of the filling layer 12 located within the opening OPN, in a direction perpendicular to the main surface of the base substrate BS, is greater than or equal to 1.2 times the minimum dimension H5 of the light-emitting element EME, in a direction perpendicular to the main surface of the base substrate BS. For example, the maximum dimension H4 is greater than or equal to 1.5 times the minimum dimension H5. For example, the maximum dimension H4 is greater than or equal to 1.8 times the minimum dimension H5. For further example, the maximum dimension H4 is greater than or equal to 2 times the minimum dimension H5. The maximum dimension H4 is less than or equal to 2.5 times the minimum dimension H5. The minimum dimension H5 may also be the thickness of the light-emitting element EME at the center of the light-emitting element.

[0071] For example, as shown in FIG. 2 to FIG. 7 , the maximum dimension H4 is less than or equal to 3 times the minimum dimension H5 .

[0072] As shown in FIG. 2 , the maximum thickness H3 of the pixel defining layer PDL may be the sum of the maximum dimension H4 and the minimum dimension H5 .

[0073] For example, the maximum thickness H3 of the pixel defining layer PDL is 1-1.5 μm, for example, 1.2 μm.

[0074] For example, the thickness of the first electrode E1 is about 100-150 nm, for example, 120 nm.

[0075] For example, the thickness of the second electrode E2 is about 12-18 nm, for example, 15 nm.

[0076] For example, the thickness of the light-emitting functional layer EL is about 200-400 nm, and further for example, 300-400 nm.

[0077] For example, the minimum dimension H5 of the light emitting element EME in a direction perpendicular to the main surface of the base substrate BS is approximately 312-568 nm.

[0078] Of course, the values ​​of various specific dimensions are only examples, and the dimensions of each component can be adjusted as needed.

[0079] FIG2 shows the maximum thickness H3 , the maximum dimension H4 , and the minimum dimension H5 . The maximum thickness H3 , the maximum dimension H4 , and the minimum dimension H5 in the remaining cross-sectional views may refer to FIG2 .

[0080] In the embodiments of the present disclosure, the thickness of a component refers to the dimension of the component in direction Z. Direction Z is a direction perpendicular to the main surface of the substrate.

[0081] For example, as shown in Figures 2 to 7 , the refractive index of filling layer 12 is greater than or equal to 1.7. For example, the material of filling layer 12 includes a matrix material and filler particles doped therein. For example, the filler particles include at least one of zirconium oxide particles and titanium oxide particles, but are not limited thereto and can be determined as needed. Because the filler particles have a higher refractive index, filling layer 12 can also have a higher refractive index. The filler particles are nanometer-sized.

[0082] The refractive index of the filler particles is greater than that of the matrix material. For example, filler particles may also be referred to as high-refractive-index particles. By placing high-refractive-index filler particles in the matrix material, the refractive index of the filler layer 12 can be increased to be greater than the refractive index of the matrix material but smaller than the refractive index of the filler particles. The greater the amount of filler particles, the greater the refractive index of the filler layer 12.

[0083] For example, the matrix material of the filling layer 12 includes at least one of acrylic resin and epoxy resin. Of course, other suitable materials may also be used.

[0084] The refractive index of epoxy resin is about 1.5-1.57, and the refractive index of epoxy resin with filler particles may be greater than or equal to 1.7. For example, in some embodiments, the filling layer 12 is made of epoxy resin with filler particles, and the refractive index is about 1.7 or 1.8.

[0085] The refractive index of acrylic resin is about 1.5, and the refractive index of acrylic resin with filler particles may be greater than or equal to 1.7. For example, in some embodiments, the filling layer 12 is made of acrylic resin with filler particles, and the refractive index is about 1.7.

[0086] 2 to 7 , the refractive index of the light extraction structure 11 is less than or equal to 1.5. For example, the material of the light extraction structure 11 includes acrylic resin (refractive index is about 1.5).

[0087] For example, the display substrate further includes an encapsulation layer TFE configured to encapsulate the light emitting element EME, and the encapsulation layer TFE is located on the side of the filling layer 12 away from the base substrate BS. The encapsulation layer TFE encapsulates the light emitting element EME to prevent water and oxygen from invading.

[0088] For example, the encapsulation layer TFE may be a thin film encapsulation layer. For example, in the embodiments of the present disclosure, the material of the encapsulation layer TFE may also include an inorganic encapsulation film, an organic encapsulation film, and a stack of inorganic encapsulation films. For example, the material of the inorganic encapsulation film includes at least one of silicon oxide (SiOx), silicon nitride (SiNx), and silicon oxynitride (SiNxOy), and the material of the organic encapsulation film includes, but is not limited to, an organic resin.

[0089] As shown in FIG. 7 , the light-emitting functional layer EL includes a common layer LY and a unit structure layer M0 . The common layer LY is shared by a plurality of sub-pixels, and the unit structure layer M0 is located in an opening OPN.

[0090] As shown in FIG. 7 , the common layer LY includes an electron injection layer EIL, but the present invention is not limited thereto and may be determined according to actual needs.

[0091] As shown in Figure 7, the unit structure layer M0 includes a unit structure layer M1 and a unit structure layer M2. For example, the unit structure layer M1 includes at least one of a hole injection layer HIL and a hole transport layer HTL, and the unit structure layer M2 includes a light-emitting layer EML. In the embodiments of the present disclosure, the hole injection layer HIL, the hole transport layer HT, the light-emitting layer EML, and the electron injection layer EIL can all be made of commonly used materials.

[0092] As shown in Figures 2 to 7, a spacer layer 18 is provided between the filling layer 12 and the light extraction structure 11. As shown in Figures 2 to 6, the spacer layer 18 includes a second electrode E2. As shown in Figure 7, the spacer layer 18 is the second electrode E2 and the common layer LY. For example, the thickness of the second electrode E2 is about a dozen nanometers, for example, 12-18 nm, and the thickness of the common layer LY (electron injection layer EIL) is usually between several dozen and over a hundred nanometers. Due to the small thickness of the spacer layer 18, it may absorb some light, but it does not affect the total internal reflection interface. That is, in the presence of the spacer layer 18, the total internal reflection interface is still on the side of the light extraction structure 11.

[0093] As shown in Figures 2 to 7 , the display substrate is a top-emitting structure. The upper side of the display substrate shown in Figures 2 to 7 is the light-emitting side.

[0094] As shown in Figure 8, the pixel defining portion P0 includes a first pixel defining portion PDL1 and a second pixel defining portion PDL2. The first pixel defining portion PDL1 extends along direction X, and the second pixel defining portion PDL2 extends along direction Y. A plurality of first pixel defining portions PDL1 arranged at intervals along direction X are provided between two adjacent second pixel defining portions PDL2.

[0095] For example, the thickness of the first pixel-defining portion PDL1 is smaller than the thickness of the second pixel-defining portion PDL2. That is, the dimension of the first pixel-defining portion PDL1 in the direction Z is smaller than the dimension of the second pixel-defining portion PDL2 in the direction Z. This facilitates the use of an inkjet printing process to manufacture at least one film layer in the light-emitting functional layer.

[0096] For example, the structure of the first pixel defining part PDL1 is different from the structure of the second pixel defining part PDL2 .

[0097] For example, the second pixel defining portion PDL2 may adopt the above-mentioned pixel defining layer PDL having the light extraction structure 11. For example, the first pixel defining portion PDL1 adopts a commonly used pixel defining material.

[0098] As shown in FIG8 , a sub-pixel 100 includes a first sub-pixel 101, a second sub-pixel 102, and a third sub-pixel 103. For example, the first sub-pixel 101, the second sub-pixel 102, and the third sub-pixel 103 are sub-pixels that emit light of different colors. The embodiments of the present disclosure are described using the example where the first sub-pixel 101 is a red sub-pixel, the second sub-pixel 102 is a green sub-pixel, and the third sub-pixel 103 is a blue sub-pixel. For example, a pixel includes at least three sub-pixels that emit light of different colors. For example, a pixel includes the first sub-pixel 101, the second sub-pixel 102, and the third sub-pixel 103.

[0099] As shown in FIG8 , taking direction X as the row direction and direction Y as the column direction as an example, a column of sub-pixels emits light of the same color.

[0100] As shown in Figure 8, the size of the light-emitting area (light-emitting element) of the sub-pixel in the direction Y (the size of the long axis) is related to the pixel resolution. For example, the size of the light-emitting area (light-emitting element) of the sub-pixel in the direction Y (the size of the long axis) is approximately 50-150μm, but is not limited to this. Typically, for a display substrate with 255PPI, the size of the long axis of the sub-pixel is approximately 75μm, and for a display substrate with 160PPI, the size of the long axis of the sub-pixel is approximately 105μm. PPI is the number of pixels per inch (Pixels Per Inch).

[0101] As shown in FIG8 , the size of the light emitting area (light emitting element) of the sub-pixel in the direction X (the size of the short axis) is approximately 30-50 μm, but is not limited thereto.

[0102] As shown in Figures 2, 6, and 7, embodiments of the present disclosure provide a display substrate that utilizes a pixel defining layer that enhances light extraction. A pixel defining layer (PDL) is fabricated in the shape of a subpixel on a first electrode E1 using a liquid-repellent material. The upper surface of the main body MP of the PDL is liquid-repellent. A light extraction structure 11 (a low-refractive-index film layer) is disposed on the side of the main body MP of the PDL. The refractive index of the light extraction structure 11 is less than or equal to 1.5. A light-emitting functional (EL) layer is fabricated within the subpixel using inkjet printing. A filler layer 12 is disposed above the EL. The filler layer 12 includes a matrix material and filler particles having a high refractive index, with the refractive index of the filler layer 12 exceeding 1.7. A TFE encapsulation layer is disposed on the filler layer 12. Light emitted from the EL at high angles to the side of the pixel defining structure P0 of the PDL undergoes total internal reflection at the light extraction structure 11, thereby reflecting the lateral light in the forward direction. Therefore, this structure can enhance forward light extraction from the light-emitting element.

[0103] The following will further describe in detail the manufacturing method of the display substrate shown in Figures 2, 6 and 7 with reference to the accompanying drawings. The manufacturing method of the display substrate is as follows.

[0104] (1) A pixel circuit 13 is formed on the base substrate BS.

[0105] (2) A planarization layer PLN (insulating layer 14 ) is formed on the pixel circuit 13 .

[0106] (3) A first electrode E1 is formed on the flat layer PLN (insulating layer 14 ).

[0107] (4) A main body MP of a pixel defining layer PDL is formed on the first electrode E1.

[0108] (5) A light extraction structure 11 (low refractive index film layer) is formed on the side of the main body MP of the pixel definition layer PDL. The refractive index of the light extraction structure 11 is less than 1.5.

[0109] (6) The light-emitting functional layer EL is formed by inkjet printing process.

[0110] (7) A second electrode E2 is formed on the light-emitting functional layer EL.

[0111] (8) A filling layer FL is formed on the second electrode E2, and the refractive index of the filling layer FL is higher than 1.7.

[0112] (9) An encapsulation layer ECS is formed on the filling layer FL.

[0113] For example, in step (1), the pixel circuit 13 includes a thin film transistor and a storage capacitor.

[0114] For example, in step (2), the shape of the first electrode E1 is consistent with the shape of the sub-pixel.

[0115] As shown in Figure 3, a light extraction structure 11 is first fabricated from a low-refractive-index material. For example, the cross-section of the light extraction structure 11 is trapezoidal and has a refractive index of less than 1.5. A liquid-repellent material is then used to fabricate the main body MP of the pixel defining layer (PDL) outside the light extraction structure 11. The main body MP has a refractive index of approximately 1.65. A light-emitting functional layer EL is then formed within the sub-pixel using inkjet printing. A second electrode E2 is formed on the light-emitting functional layer EL, and a filling layer 12 is formed above the second electrode E2. The filling layer 12 is a structure in which filler particles are doped into a matrix material, and the refractive index of the filling layer 12 is greater than 1.7. An encapsulation layer TFE is then formed above the filling layer 12 to complete the encapsulation. High-angle light emitted from the light-emitting functional layer EL to the side of the pixel defining structure P0 (light extraction structure 11) is totally internally reflected by the low-refractive-index light extraction structure 11, thereby reflecting the lateral light in the forward direction. This structure can enhance the forward light output of the light-emitting element.

[0116] As shown in Figure 4, a light extraction structure 11 is first fabricated from a low-refractive-index material. The cross-section of the light extraction structure 11 is trapezoidal, and its refractive index is less than 1.5. A main body MP of the pixel defining layer (PDL) is then formed above the light extraction structure 11 using a liquid-repellent material. The main body MP has a refractive index of approximately 1.65. A light-emitting functional layer EL is then formed within the sub-pixel using inkjet printing. A second electrode E2 is formed on the light-emitting functional layer EL, and a filling layer 12 is formed above the second electrode E2. The filling layer 12 is constructed by doping filler particles in a matrix material, and its refractive index is greater than 1.7. Finally, an encapsulation layer TFE is formed above the filling layer 12 to complete the encapsulation. High-angle light emitted from the light-emitting functional layer EL to the side of the pixel defining structure P0 (light extraction structure 11) is totally reflected by the low-refractive-index light extraction structure 11, thereby reflecting the lateral light in the forward direction. This structure can enhance the forward light output of the light-emitting element.

[0117] As shown in Figure 5 , a planar layer PLN (insulating layer 14) is first formed on the pixel circuit 13 and the second conductive element CEb. A first conductive element CEa and a first electrode E1 are then formed on the planar layer PLN (insulating layer 14). A light extraction structure 11 is then fabricated using a high-reflectivity metal. The cross-section of the light extraction structure 11 can be trapezoidal, and the high-reflectivity metal can be silver (Ag). The thickness of the light extraction structure 11 is less than that of the main body MP. The thickness of the light extraction structure 11 is less than 1.2 μm. For example, the thickness of the light extraction structure 11 can be 0.8-1.1 μm, but this is not limited to this and can be determined as needed. Then, a liquid-repellent material is used to form the main body MP of the pixel defining layer PDL on the outside of the light extraction structure 11. The refractive index of the main body M is about 1.65. The light-emitting functional layer EL is made in the sub-pixel by inkjet printing, and the second electrode E2 is formed on the light-emitting functional layer EL. A filling layer 12 is formed on the second electrode E2. The filling layer 12 uses a structure in which filling particles are doped in a matrix material. The refractive index of the filling layer 12 is higher than 1.7. Then, an encapsulation layer TFE is formed on the filling layer 12 to complete the encapsulation. The large-angle light emitted from the light-emitting functional layer EL to the side of the pixel defining layer PDL (light extraction structure 11) is reflected by the light extraction structure 11 with high reflectivity, thereby reflecting the lateral light to the forward direction. Therefore, this structure can enhance the forward light output of the light-emitting element. In addition, the light extraction structure 11 made of high-reflectivity metal can be connected to the second electrode E2 as an auxiliary electrode, thereby reducing the voltage drop of a large-size display substrate.

[0118] In the embodiment of the present disclosure, as shown in FIG. 5 to FIG. 7 , the thickness of the planar layer PLN (insulating layer 14 ) is approximately 1 to 2 μm, but is not limited thereto and can be determined according to needs.

[0119] As shown in Figure 8, based on a conventional line bank structure, the first pixel-defining portion (PDL) 1 is made of a low-refractive-index material, while the second pixel-defining portion (PDL) 2 utilizes the pixel-defining layer (PDL) with the light extraction structure and lyophobic material described in the previous embodiment. The light-emitting functional layer (EL) is inkjet-printed within the subpixel. The line bank structure of the pixel-defining layer (PDL) allows ink to flow throughout the entire column, improving the uniformity of the EL within the subpixel. A second electrode (E2) is formed on the EL, and a filling layer (12) is formed above the second electrode (E2). Filling layer (12) is constructed by doping filler particles in a matrix material with a refractive index greater than 1.7. An encapsulation layer (TFE) is then formed above filling layer (12) to complete the encapsulation. High-angle light emitted from the light-emitting functional layer (E) to the side of the pixel-defining layer (PDL) undergoes total internal reflection (TIR) ​​at the low-refractive-index light extraction structure (11), reflecting the lateral light in the forward direction. This structure enhances the forward light output of the OLED.

[0120] For example, in an embodiment of the present disclosure, the insulating layer 14 includes at least one of an inorganic insulating layer and an organic insulating layer. For example, the inorganic insulating material includes silicon oxide, silicon nitride, silicon oxynitride, etc., and the organic insulating material includes resin, but is not limited thereto.

[0121] For example, the base substrate BS includes a flexible material such as polyimide or a rigid material such as glass, but is not limited thereto.

[0122] For example, one of the first electrode E1 and the second electrode E2 is an anode, and the other of the first electrode E1 and the second electrode E2 is a cathode.

[0123] For example, the material of the first electrode E1 of the light-emitting element includes a conductive material, such as, but not limited to, at least one of silver (Ag) or indium tin oxide (ITO). For example, the first electrode E1 of the light-emitting element has a three-layer stacked structure of ITO / Ag / ITO, but not limited to this. In other embodiments, the material of the first electrode E1 of the light-emitting element includes aluminum (Al) and tungsten oxide (WOx). For example, the first electrode E1 includes a stacked layer of aluminum and tungsten oxide, and the aluminum layer is closer to the substrate than the tungsten oxide layer.

[0124] For example, the material of the second electrode E2 of the light-emitting element includes a conductive material, such as at least one of magnesium (Mg), silver (Ag), or indium zinc oxide (IZO), but is not limited thereto. For example, in some embodiments, the material of the second electrode E2 of the light-emitting element includes a Mg / Ag alloy.

[0125] For example, at least one of the first conductive element CEa and the second conductive element CEb may be made of a conductive material such as a metal material.

[0126] A light-emitting element generally includes a first electrode, a light-emitting functional layer, and a second electrode, formed sequentially on a substrate. For example, the light-emitting functional layer includes a light-emitting layer. In other embodiments, the light-emitting functional layer includes, in addition to the light-emitting layer, at least one of a hole transport layer, a hole injection layer, an electron injection layer, and an electron transport layer. For example, a light-emitting element includes the following structure, formed sequentially: a first electrode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron injection layer, an electron transport layer, and a second electrode. For example, the first electrode is an anode, and the second electrode is a cathode, but this is not limited to this.

[0127] In the embodiments of the present disclosure, the interface between one element and another element refers to the contact surface of the two elements.

[0128] At least one embodiment of the present disclosure provides a display device comprising any of the above-mentioned display substrates. For example, the display device may be any product or component having a display function, such as a television, digital camera, mobile phone, watch, tablet computer, laptop computer, or navigation system, that includes an organic light-emitting diode display device.

[0129] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A display substrate, comprising: substrate substrate; A light emitting element, located on the base substrate, comprising a first electrode, a second electrode, and a light emitting functional layer located between the first electrode and the second electrode; a pixel defining layer including a pixel defining portion and an opening, wherein the opening is configured to expose at least a portion of the first electrode; as well as A filling layer, located on a side of the second electrode facing away from the substrate; The pixel defining portion includes a light extraction structure, and the refractive index of the filling layer is greater than the refractive index of the light extraction structure.

2. The display substrate according to claim 1, wherein: The side surface of the light extraction structure is a total reflection interface.

3. The display substrate according to claim 1 or 2, wherein: The pixel defining portion further includes a body having a refractive index different from a refractive index of the light out-coupling structure.

4. The display substrate according to claim 3, wherein: The light extraction structure is at least located on a side surface of the main body.

5. The display substrate according to claim 3, wherein: The main body is located at least on a side surface of the light extraction structure.

6. The display substrate according to claim 5, wherein: The light extraction structure includes a conductive reflective layer.

7. The display substrate according to claim 6, further comprising a first conductive element, wherein: The second electrode is connected to the first conductive element through the light extraction structure.

8. The display substrate according to claim 7, wherein: The first conductive element and the first electrode are located in the same layer.

9. The display substrate according to claim 7, further comprising a second conductive element, wherein: The first conductive element is connected to the second conductive element.

10. The display substrate according to claim 9, further comprising a pixel circuit, wherein: The first electrode is connected to the pixel circuit, the pixel circuit is configured to drive the light emitting element, and the second conductive element is insulated from the pixel circuit.

11. The display substrate according to any one of claims 6 to 10, wherein: The area of ​​the surface of the light extraction structure facing away from the base substrate is smaller than the area of ​​the surface of the light extraction structure close to the base substrate, and the area of ​​one end of the opening facing away from the base substrate is larger than the area of ​​one end of the opening close to the base substrate.

12. The display substrate according to claim 3, wherein: The main body is located on a side of the light extraction structure away from the base substrate.

13. The display substrate according to claim 12, wherein: A maximum thickness of the body is smaller than a maximum thickness of the light extraction structure.

14. The display substrate according to any one of claims 1 to 13, wherein: A maximum dimension of a portion of the filling layer located in the opening in a direction perpendicular to the main surface of the base substrate is greater than or equal to a minimum dimension of the light emitting element in a direction perpendicular to the main surface of the base substrate.

15. The display substrate according to claim 14, wherein: A maximum dimension of a portion of the filling layer located in the opening in a direction perpendicular to the main surface of the base substrate is greater than or equal to 1.2 times a minimum dimension of the light emitting element in a direction perpendicular to the main surface of the base substrate.

16. The display substrate according to any one of claims 1 to 15, wherein: A difference between a refractive index of the filling layer and a refractive index of the light extraction structure is greater than or equal to 0.

2.

17. The display substrate according to any one of claims 1 to 16, wherein: The refractive index of the filling layer is greater than or equal to 1.7, and the refractive index of the light extraction structure is less than or equal to 1.

5.

18. The display substrate according to any one of claims 1 to 17, further comprising an encapsulation layer, wherein: The encapsulation layer is configured to encapsulate the light emitting element, and the encapsulation layer is located on a side of the filling layer away from the base substrate.

19. A display device comprising the display substrate according to any one of claims 1 to 18.

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