Display panel, preparation method thereof and display device

Abstract

The application provides a display panel, a preparation method thereof and a display device. The array layer of the display panel comprises a driving circuit and a metal connection structure. The metal connection structure comprises a first metal structure, a second metal structure and a third metal structure. The first metal structure is electrically connected with the driving circuit. The light emitting element comprises a first electrode layer, a first common light emitting layer, a charge generation layer, a second common light emitting layer and a second electrode layer. The first electrode layer is electrically connected with the driving circuit through the first metal structure. The second metal structure is electrically connected with the charge generation layer. The third metal structure is electrically connected with the second electrode layer. The area of the first common light emitting layer in the orthogonal projection of the substrate is S1. The area of the charge generation layer in the orthogonal projection of the substrate is S2. The area of the second common light emitting layer in the orthogonal projection of the substrate is S3. S1 < S2 < S3 is satisfied. The second metal structure electrically connected with the charge generation layer is arranged, and the projection areas of different film layers are adjusted, so that the display effect of the display panel as a whole is ensured.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of display, and in particular to a display panel, a preparation method thereof and a display device. BACKGROUND

[0002] With the continuous development of display technology, display panels have been widely used in people's production and life. In order to better meet people's needs, the display panel can be adjusted, for example, the part of the structure and the film layer in the display panel is adjusted, so as to improve the overall effect of the display panel. SUMMARY

[0003] Embodiments of the present application provide a display panel, a preparation method thereof and a display device, by setting the second metal structure electrically connected with the charge generating layer, and adjusting the projection area of different film layers, so as to ensure the overall display effect of the display panel.

[0004] In a first aspect, embodiments of the present application provide a display panel, comprising: a display area and a non-display area, the non-display area surrounds at least part of the display area;

[0005] a substrate;

[0006] an array layer, the array layer is located on one side of the substrate; the array layer comprises a drive circuit and a metal connection structure, the metal connection structure comprises a first metal structure located in the display area and a second metal structure and a third metal structure located in the non-display area; the first metal structure is electrically connected with the drive circuit, the first metal structure, the second metal structure and the third metal structure are insulatively arranged; the minimum distance between the orthographic projection of the second metal structure to the substrate and the display area is less than the minimum distance between the orthographic projection of the third metal structure to the substrate and the display area;

[0007] a light emitting element, located in the display area and located on the side of the array layer away from the substrate, the light emitting element comprises a first electrode layer, a first common light emitting layer, a charge generating layer, a second common light emitting layer and a second electrode layer; the first electrode layer is located on the side of the first metal structure away from the substrate; the first common light emitting layer is located on the side of the first electrode layer away from the array layer, the charge generating layer is located on the side of the first common light emitting layer away from the first electrode layer, the second common light emitting layer is located on the side of the charge generating layer away from the first common light emitting layer, and the second electrode layer is located on the side of the second common light emitting layer away from the charge generating layer;

[0008] the first electrode layer is electrically connected with the drive circuit through the first metal structure, the second metal structure is electrically connected with the charge generating layer, and the third metal structure is electrically connected with the second electrode layer.

[0009] The orthographic projection area of ​​the first common light-emitting layer onto the substrate is S1, the orthographic projection area of ​​the charge generation layer onto the substrate is S2, and the orthographic projection area of ​​the second common light-emitting layer onto the substrate is S3; and the following conditions are satisfied: S1<S2<S3.

[0010] Optionally, the first common light-emitting layer includes a first light-emitting layer, and the second common light-emitting layer includes a second light-emitting layer; a light-on voltage of the first light-emitting layer is V1th, and a light-on voltage of the second light-emitting layer is V2th;

[0011] The first metal structure provides a first voltage V1 for the first electrode layer; the third metal structure provides a second voltage V2 for the second electrode layer;

[0012] When V1-V2<V1th+V2th+ΔV, the second metal structure provides a third voltage V3 to the charge generation layer; wherein ΔV is a preset adjustment voltage value.

[0013] Optionally, V1>V3>V2.

[0014] Optionally, the second metal structure includes at least one first metal unit; the first metal unit is located on one side of the display area and surrounds a portion of the display area;

[0015] The third metal structure includes at least one second metal unit; the second metal unit is located on one side of the display area and surrounds a portion of the display area.

[0016] Optionally, the first metal unit and the second metal unit are located on the same side or different sides of the display area.

[0017] Optionally, the second metal structure includes a third metal unit, and the third metal unit surrounds the display area;

[0018] The third metal structure includes a fourth metal unit, and the fourth metal unit surrounds the third metal unit.

[0019] Optionally, the first metal structure, the second metal structure and the third metal structure are arranged in the same layer.

[0020] In a second aspect, an embodiment of the present invention provides a method for manufacturing a display panel, wherein the display panel includes a display area and a non-display area, wherein the non-display area surrounds at least a portion of the display area;

[0021] providing a substrate;

[0022] An array layer is prepared, the array layer being located on one side of the substrate; the array layer comprising a driving circuit and a metal connection structure, the metal connection structure comprising a first metal structure located in the display area and a second metal structure and a third metal structure located in the non-display area; the first metal structure is electrically connected to the driving circuit, and the first, second, and third metal structures are insulated from each other; and the minimum distance between the orthographic projection of the second metal structure onto the substrate and the display area is less than the minimum distance between the orthographic projection of the third metal structure onto the substrate and the display area.

[0023] A first electrode layer, a first common light-emitting layer, a charge generating layer, a second common light-emitting layer and a second electrode layer of a light-emitting element are prepared in sequence; the first electrode layer is located on a side of the first metal structure away from the substrate; the first common light-emitting layer is located on a side of the first electrode layer away from the array layer, the charge generating layer is located on a side of the first common light-emitting layer away from the first electrode layer, the second common light-emitting layer is located on a side of the charge generating layer away from the first common light-emitting layer, and the second electrode layer is located on a side of the second common light-emitting layer away from the charge generating layer; the first electrode layer is electrically connected to the driving circuit through the first metal structure, the second metal structure is electrically connected to the charge generating layer, and the third metal structure is electrically connected to the second electrode layer; wherein the orthographic projection area of ​​the first common light-emitting layer onto the substrate is S1, the orthographic projection area of ​​the charge generating layer onto the substrate is S2, and the orthographic projection area of ​​the second common light-emitting layer onto the substrate is S3; satisfying: S1<S2<S3.

[0024] Optionally, sequentially preparing a first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer, and a second electrode layer of a light-emitting element includes:

[0025] preparing a first electrode layer;

[0026] Using a first mask to prepare a first common light-emitting layer;

[0027] preparing a charge generation layer using a second mask;

[0028] A second common light-emitting layer is prepared using a third mask; wherein the opening size of the first mask is smaller than the opening size of the second mask, and the opening size of the second mask is smaller than the opening size of the third mask;

[0029] A second electrode layer is prepared.

[0030] In a third aspect, an embodiment of the present invention provides a display device, comprising the display panel described in any one of the first aspects.

[0031] The embodiment of the present application provides a display panel, the display panel comprises a substrate and an array layer, the array layer comprises a driving circuit and a metal connection structure, the metal connection structure comprises a first metal structure, a second metal structure and a third metal structure, wherein the first metal structure is electrically connected with a first electrode of a light emitting element, and the first metal structure is located in a display area of the display panel; the second metal structure is electrically connected with a charge generation layer of the light emitting element, and the second metal structure is located in a non-display area of the display panel; and the third metal structure is electrically connected with a second electrode layer of the light emitting element, and the third metal structure is located in the non-display area. Wherein the minimum distance between the orthographic projection of the second metal structure to the substrate and the display area is less than the minimum distance between the orthographic projection of the third metal structure to the substrate and the display area, that is, the second metal structure is closer to the display area than the third metal structure; further, in order to ensure that the charge generation layer in the light emitting element is electrically connected with the second metal structure and is not interfered by other metal wires, when the first common light emitting layer, the charge generation layer and the second common light emitting layer are prepared, the deposition areas of the three groups are adjusted, so that the orthographic projection area of the first common light emitting layer to the substrate is S1, the orthographic projection area of the charge generation layer to the substrate is S2, and the orthographic projection area of the second common light emitting layer to the substrate is S3; it satisfies: S1 < S2 < S3, so as to ensure that the charge generation layer is electrically connected with the second metal structure, and can be connected with an electrical signal when needed, thereby ensuring the light emitting effect of the light emitting element, and further improving the display effect of the display panel as a whole.

[0032] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical scheme of the exemplary embodiments of the present application, the drawings needed in the description of the embodiments are briefly introduced below. Obviously, the drawings introduced are only a part of the drawings of the embodiments to be described by the present application, and not all the drawings. Those skilled in the art can also obtain other drawings from these drawings without creating labor.

[0034] Figure 1 is a structural schematic diagram of a display panel provided by the embodiment of the present application;

[0035] Figure 2 is Figure 1 is a sectional schematic diagram along the section line A-A' in

[0036] Figure 3 is a structural schematic diagram of a light emitting element provided by the embodiment of the present application;

[0037] Figure 4is a structural diagram of another display panel provided by an embodiment of the present invention;

[0038] Figure 5 is a structural diagram of another display panel provided by an embodiment of the present invention;

[0039] Figure 6 is a structural diagram of another display panel provided by an embodiment of the present invention;

[0040] Figure 7 is a structural diagram of another display panel provided by an embodiment of the present invention;

[0041] Figure 8 yes Figure 1 Another schematic cross-sectional view along the section line AA';

[0042] Figure 9 yes Figure 1 Another schematic cross-sectional view along the section line AA';

[0043] Figure 10 is a flow chart of a method for manufacturing a display panel provided by an embodiment of the present invention;

[0044] Figure 11 is a flow chart of another method for manufacturing a display panel provided by an embodiment of the present invention;

[0045] Figure 12 It is a structural schematic diagram of a display device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0047] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a system, product, or device comprising a series of units is not necessarily limited to those steps or units explicitly listed, but may include other units that are not explicitly listed or that are inherent to these products or devices.

[0048] Figure 1is a structural diagram of a display panel provided by an embodiment of the present invention, Figure 2 yes Figure 1 A schematic cross-sectional view along the section line A-A', Figure 3 This is a schematic diagram of the structure of a light emitting element provided by an embodiment of the present invention, with reference to Figures 1 to 3 As shown, an embodiment of the present invention provides a display panel 10, which includes: a display area AA and a non-display area NA, wherein the non-display area NA surrounds at least a portion of the display area AA; a substrate 100; an array layer 200, wherein the array layer 200 is located on one side of the substrate 100; the array layer 200 includes a driving circuit 210 and a metal connection structure 220, wherein the metal connection structure 220 includes a first metal structure 221 located in the display area AA and a second metal structure 222 and a third metal structure 223 located in the non-display area NA; the first metal structure 221 is located in the display area AA and the second metal structure 222 and the third metal structure 223 are located in the non-display area NA; the first metal structure 221 is located in the display area AA and the non-display area NA is located. The structure 221 is electrically connected to the driving circuit 210, and the first metal structure 221, the second metal structure 222 and the third metal structure 223 are insulated. The minimum distance between the orthographic projection of the second metal structure 222 to the substrate 100 and the display area AA is less than the minimum distance between the orthographic projection of the third metal structure 223 to the substrate 100 and the display area AA. The light-emitting element 300 is located in the display area AA and on the side of the array layer 200 away from the substrate 100. The light-emitting element 300 includes a first electrode layer 310, a first common light-emitting layer 320, and an electrode. The charge generation layer 330, the second common light-emitting layer 340 and the second electrode layer 350; the first electrode layer 310 is located on the side of the first metal structure 221 away from the substrate 100; the first common light-emitting layer 320 is located on the side of the first electrode layer 310 away from the array layer 200, the charge generation layer 330 is located on the side of the first common light-emitting layer 320 away from the first electrode layer 310, the second common light-emitting layer 340 is located on the side of the charge generation layer 330 away from the first common light-emitting layer 320, and the second electrode layer 350 is located on the second common light-emitting layer 340. A side away from the charge generation layer 330; the first electrode layer 310 is electrically connected to the driving circuit 210 through the first metal structure 221, the second metal structure 222 is electrically connected to the charge generation layer 330, and the third metal structure 223 is electrically connected to the second electrode layer 350; wherein, the orthographic projection area of ​​the first common light-emitting layer 320 to the substrate 100 is S1, the orthographic projection area of ​​the charge generation layer 330 to the substrate 100 is S2, and the orthographic projection area of ​​the second common light-emitting layer 340 to the substrate 100 is S3; satisfying: S1<S2<S3.

[0049] Among them, reference Figure 1 and Figure 2As shown, the display panel 10 includes a display area AA, and a light-emitting element 300 is disposed in the display area AA. The display function of the display panel 10 is achieved by driving the light-emitting element 300 to emit light. The display panel 10 also includes a non-display area NA, which surrounds at least a portion of the display area AA. The specific locations of the display area AA and the non-display area NA are not specifically limited in this embodiment of the present invention. The display panel 10 also includes a display controller, such as a driver chip (not specifically shown in the figure), disposed in the non-display area NA. Signals transmitted by the display controller can drive the light-emitting element 300 to emit light, thereby ensuring the display effect of the display panel 10.

[0050] Specifically, the display panel 10 includes an array layer 200 located on one side of the substrate 100. The display panel 10 also includes a plurality of light-emitting elements 300 located on one side of the array layer 200. The array layer 200 is used to drive the light-emitting elements 300 to emit light and display, thereby realizing the display function of the display panel 10. The plurality of light-emitting elements 300 in the display panel 10 have different arrangements. Figure 1 It is only shown that the display panel 10 includes a plurality of light emitting elements 300 , and the embodiment of the present invention does not provide examples one by one for the specific arrangement of the light emitting elements 300 .

[0051] Specifically, refer to Figure 1 and Figure 2 As shown, the array layer 200 includes a driving circuit 210. The light-emitting element 300 of the display panel 10 is electrically connected to the driving circuit 210. The driving circuit 210 drives the light-emitting element 300 to achieve the light-emitting effect of the display panel 10. Specifically, the driving circuit 210 includes at least one transistor 2101. The transistor 2101 is electrically connected to the light-emitting element 300 to provide a driving current to the light-emitting element 300, thereby ensuring the normal display of the display panel 10. Furthermore, the driving circuit 210 may include "4T1C", "7T1C" and "8T1C", etc., where "T" represents a transistor and "C" represents a capacitor. Figure 2 The driving circuit 210 is not specifically shown in the figure, and only one transistor 2101 is used as an example. Furthermore, the array layer 200 includes multiple stacked film layers, such as a gate insulating layer 201, an interlayer insulating layer 202, a first planarizing layer 203, a second planarizing layer 204, and a pixel definition layer 205. The specific film layer types and quantities in the array layer 200 can be adaptively adjusted according to different needs, and the embodiments of the present invention do not specifically limit them here. Furthermore, Figure 2 The transistor 2101 shown in the driving circuit 210 includes: an active layer, a gate, a drain and a source, etc. The specific configuration of the transistor 2101 can also be adaptively adjusted according to needs, and the embodiment of the present invention does not specifically limit this.

[0052] For further reference, Figure 2 As shown, the array layer 200 further includes a metal connection structure 220, and the metal connection structure 220 includes a first metal structure 221, a second metal structure 222, and a third metal structure 223, wherein the first metal structure 221 is located in the display area AA, the second metal structure 222 and the third metal structure 223 are located in the non-display area NA, and the minimum distance between the orthographic projection of the second metal structure 222 to the substrate 100 and the display area AA is less than the minimum distance between the orthographic projection of the third metal structure 223 to the substrate 100 and the display area AA, with reference to FIG. Figure 1 As shown, the minimum distance L1 between the second metal structure 222 and the display area AA is less than the minimum distance L2 between the third metal structure 223 and the display area AA. In other words, the second metal structure 222 is closer to the display area AA than the third metal structure 223. Furthermore, the first metal structure 221, the second metal structure 222, and the third metal structure 223 transmit different electrical signals, and are therefore insulated from each other.

[0053] Among them, the light-emitting element 300 located on the side of the array layer 200 away from the substrate 100 includes multiple film layers. Specifically, the light-emitting element 300 includes a first electrode layer 310, a first common light-emitting layer 320, a charge generation layer 330, a second common light-emitting layer 340 and a second electrode layer 350 in sequence along the thickness direction of the display panel 10, and the first electrode layer 310 is located on the side of the first metal structure 221 away from the substrate 100; the first common light-emitting layer 320 is located on the side of the first electrode layer 310 away from the array layer 200, the charge generation layer 330 is located on the side of the first common light-emitting layer 320 away from the first electrode layer 310, the second common light-emitting layer 340 is located on the side of the charge generation layer 330 away from the first common light-emitting layer 320, and the second electrode layer 350 is located on the side of the second common light-emitting layer 340 away from the charge generation layer 330.

[0054] Specifically, refer to Figures 1 to 3As shown, the first common light-emitting layer 320 includes a first hole injection layer 321, a first hole transport layer 322, a first light-emitting layer 323, and a first electron transport layer 324; the second common light-emitting layer 340 includes a second hole injection layer 341, a second hole transport layer 342, a second light-emitting layer 343, and a second electron transport layer 344. Optionally, the first light-emitting layer is a red-green light-emitting layer, and the second light-emitting layer is a blue light-emitting layer. When a certain voltage is applied to the first electrode layer 310 and the second electrode layer 350, the holes from the first electrode layer 310 can be injected into the hole transport layer through the hole injection layer and then transported to the light-emitting layer. The electrons from the second electrode layer 350 are transported to the light-emitting layer through the electron transport layer and form excitons in the light-emitting layer. The excitons excite the light-emitting molecules in the light-emitting layer and emit light. A hole blocking layer can also be provided in the light-emitting element 300. The hole blocking layer is used to block holes from passing through the light-emitting layer into the electron transport layer, ensuring that holes and electrons combine to form excitons in the light-emitting layer, thereby ensuring the light-emitting effect of the light-emitting element. Furthermore, the light-emitting element 300 comprises multiple light-emitting layers (i.e., a first light-emitting layer 323 and a second light-emitting layer 343) stacked in series via a charge generation layer (CGL) 330. The tandem display panel 10 enables the light-emitting element 300 to be driven at the same current density, thereby significantly improving the brightness of the display panel 10. It can be understood that the light-emitting element 300 is a tandem stacked light-emitting element (Tandem), and the display panel 10 can also be a tandem display panel (Tandem OLED).

[0055] Furthermore, the luminous effect of the light-emitting element 300 changes as the voltage difference between the first electrode layer 310 and the second electrode layer 350 changes. In particular, when the voltage difference between the first electrode layer 310 and the second electrode layer 350 is small, the luminous effect of the second light-emitting layer 343 in the light-emitting element 300 is worse than that of the first light-emitting layer 323. For example, when debugging the light-emitting element 300, the voltage difference between the first electrode layer 310 and the second electrode layer 350 decreases at low grayscales, ultimately causing the voltage across the first common light-emitting layer 320 and the second common light-emitting layer 340 to change. Alternatively, this can be understood as a voltage transmission path that remains unchanged, but the transmitted voltage difference is relatively small (the distance between the first electrode layer 310 and the second electrode layer 350 remains unchanged, but the voltage value decreases). This ultimately results in more excitons being formed in the first light-emitting layer 323 and fewer excitons being formed in the second light-emitting layer 343. In order to ensure the luminous effect of the light-emitting element 300 at low grayscale, the second metal structure 222 is electrically connected to the charge generation layer 330 between the first common light-emitting layer 320 and the second common light-emitting layer 340, that is, the second metal structure 222 provides an electrical signal to the charge generation layer 330, and adjusts the voltage value between the charge generation layer 330 and the second electrode layer 350 to ensure that sufficient excitons are formed in the second light-emitting layer 343, thereby improving the luminous effect of the light-emitting element 300 at various voltages, thereby improving the overall display effect of the display panel 10.

[0056] Specifically, the first electrode layer 310 is electrically connected to the driving circuit 210 via the first metal structure 221, i.e., the driving signal generated by the driving circuit 210 is transmitted to the first electrode layer 310 via the first metal structure 221. The third metal structure 223 is electrically connected to the second electrode layer 350, i.e., the fixed potential signal is transmitted to the second electrode layer 350 via the third metal structure 223, thereby achieving a voltage difference between the first electrode layer 310 and the second electrode layer 350, thereby achieving display of the light-emitting element 300. As described above, in order to avoid the luminous effect of the light-emitting element 300 at low grayscale, the charge generation layer 330 is also fed with an electrical signal, and the second metal structure 222 is provided to be electrically connected to the charge generation layer 330, thereby ensuring a stable voltage difference between the charge generation layer 330 and the second electrode layer 350, thereby ensuring that the stacked light-emitting layers in the light-emitting element 300 can generate sufficient excitons, thereby ensuring the display effect of the display panel 10. Optionally, the display panel 10 may be provided with a first pad (not shown in the figure) and a second pad (not shown in the figure) in the non-display area NA, the first pad and the second pad being located on one side of the display area, the first pad being electrically connected to the second metal structure 222, and the second pad being electrically connected to the third metal structure 223, for providing the voltage signal required by the light-emitting element 300.

[0057] Furthermore, the orthographic projection area of ​​the first common light emitting layer 320 onto the substrate 100 is S1, and the orthographic projection area of ​​the charge generation layer 330 onto the substrate 100 is S2, wherein S1<S2. Figure 2 As shown, the first common light-emitting layer 320 includes multiple common film layers such as the first hole injection layer 321, the first hole transport layer 322, the first light-emitting layer 323, and the first electron transport layer 324, which can be prepared using the same mask; while the charge generation layer 330 is to be electrically connected to the second metal structure 222, and in order to avoid the charge generation layer 330 being electrically connected to the first electrode layer 310, the charge generation layer 330 is prepared using another mask, so as shown in FIG. Figure 2 As shown, the orthographic projection area of ​​the first common light-emitting layer 320 onto the substrate 100 is smaller than the orthographic projection area of ​​the charge generation layer 330 onto the substrate 100. Similarly, to prevent electrical connection between the charge generation layer 330 and the second electrode layer 350, the orthographic projection area of ​​the charge generation layer 330 onto the substrate 100 is adjusted to be smaller than the orthographic projection area of ​​the second common light-emitting layer 340 onto the substrate 100; that is, the relationship S1 < S2 < S3 is satisfied, thereby ensuring the overall display effect of the display panel 10.

[0058] In summary, an embodiment of the present invention provides a display panel, wherein a first metal structure in the display panel is electrically connected to a first electrode of a light-emitting element, and the first metal structure is located in a display area of ​​the display panel; a second metal structure is electrically connected to a charge generation layer of the light-emitting element, and the second metal structure is located in a non-display area of ​​the display panel; and a third metal structure is electrically connected to the second electrode layer of the light-emitting element, and the third metal structure is located in a non-display area. In order to ensure that the charge generation layer in the light-emitting element is electrically connected to the second metal structure and is not interfered with by other metal traces, when preparing the first common light-emitting layer, the charge generation layer, and the second common light-emitting layer, the deposition areas of the three groups are adjusted to achieve an orthographic projection area S1 of the first common light-emitting layer in the light-emitting element onto the substrate, an orthographic projection area S2 of the charge generation layer onto the substrate, and an orthographic projection area S3 of the second common light-emitting layer onto the substrate; and the following conditions are satisfied: S1 < S2 < S3, ensuring that the charge generation layer is electrically connected to the second metal structure and can be connected to an electrical signal when needed, thereby ensuring the light-emitting effect of the light-emitting element and thereby improving the overall display effect of the display panel.

[0059] Continue to refer Figures 1 to 3As shown, the first common light-emitting layer 320 includes a first light-emitting layer 323, and the second common light-emitting layer 340 includes a second light-emitting layer 343; the turn-on voltage of the first light-emitting layer 323 is V1th, and the turn-on voltage of the second light-emitting layer 343 is V2th; the first metal structure 221 provides a first voltage V1 for the first electrode layer 310; the third metal structure 223 provides a second voltage V2 for the second electrode layer 350; when V1-V2<V1th+V2th+△V, the second metal structure 222 provides a third voltage V3 for the charge generation layer 330; wherein △V is a preset adjustment voltage value.

[0060] Among them, reference Figure 3 As shown, the first common light-emitting layer 320 includes a first light-emitting layer 323, and the second common light-emitting layer 340 includes a second light-emitting layer 343; the turn-on voltage of the first light-emitting layer 323 is V1th, and the turn-on voltage of the second light-emitting layer 343 is V2th. The turn-on voltage of the first light-emitting layer 323 can be understood as, when the voltage difference between the two sides of the first light-emitting layer 323 reaches V1th, the first light-emitting layer 323 performs light-emitting display; similarly, the turn-on voltage of the second light-emitting layer 343 can be understood as, when the voltage difference between the two sides of the second light-emitting layer 343 reaches V2th, the second light-emitting layer 343 performs light-emitting display.

[0061] Furthermore, when the voltage difference between the first electrode layer 310 and the second electrode layer 350 is less than V1th+V2th+ΔV, the second metal structure 222 is configured to provide a voltage value to the charge generation layer 330. In other words, when the voltage difference between the first electrode layer 310 and the second electrode layer 350 is sufficiently small, to ensure that both the first light-emitting layer 323 and the second light-emitting layer 343 can generate a large number of excitons, the second metal structure 222 provides a voltage value to the charge generation layer 330. This can increase the voltage difference between the first light-emitting layer 323 and the second light-emitting layer 343 to be relatively stable, thereby ensuring the luminous effect of the light-emitting element 300. ΔV is a preset adjustment voltage value, which can be adaptively adjusted based on different display panels 10 or different light-emitting elements 300. For example, if ΔV is 0.5V, then when V1-V2<V1th+V2th+0.5V, the charge generation layer 330 is connected to the third voltage V3 provided by the second metal structure 222. Specifically, a voltage range is set, and when the voltage reaches this range, a voltage is supplied to the charge generation layer 230. Alternatively, the voltage is supplied to the charge generation layer 230 only at low grayscales, which helps reduce power consumption. When the display reaches a low grayscale, the second metal structure 222 is turned on to supply power to the charge generation layer 230. This allows the display panel 10 to better meet the requirements of debugging at low grayscales, thereby improving product performance.

[0062] Continue to refer Figures 1 to 3 As shown, V1>V3>V2.

[0063] The first metal structure 221 provides a first voltage V1 for the first electrode layer 310; the third metal structure 223 provides a second voltage V2 for the second electrode layer 350, and the second metal structure 222 provides a third voltage V3 for the charge generation layer 330. For example, the first voltage V1 can be 5V, and the second voltage V2 can be -5V, so that there is a voltage difference between the first electrode layer 310 and the second electrode layer 350, which ensures the light emitting effect of the light emitting layer in the light emitting element 300. In order to ensure that the light emitting layer close to the first electrode layer 310 and the light emitting layer close to the second electrode layer 350 can generate more excitons, the second metal structure 222 provides the third voltage V3 for the charge generation layer 330. The third voltage V3 should satisfy: V3>V2, so as to ensure that the voltage difference at the light emitting layer close to the second electrode layer 350 can ensure that the light emitting layer generates enough excitons; and satisfy V1>V3, so as to ensure that the voltage difference at the light emitting layer close to the first electrode layer 310 can ensure that the light emitting layer generates enough excitons.

[0064] For example, V3 can satisfy: VB=R1 / R2*V1, wherein R1 / R2 is a voltage adjustment coefficient, and R1

[0065] Figure 4 is a structural schematic diagram of another display panel provided by an embodiment of the present application, Figure 5 is a structural schematic diagram of another display panel provided by an embodiment of the present application, Figure 6 is a structural schematic diagram of another display panel provided by an embodiment of the present application, Figure 7 is a structural schematic diagram of another display panel provided by an embodiment of the present application, Figures 4 to 7 As shown in the figure, the second metal structure 222 includes at least one first metal unit 222a; the first metal unit 222a is located at one side of the display area AA and surrounds part of the display area AA; the third metal structure 223 includes at least one second metal unit 223a; the second metal unit 223a is located at one side of the display area AA and surrounds part of the display area AA.

[0066] Specifically, referring to Figures 4 to 6 As shown in the figure, the second metal structure 222 includes at least one first metal unit 222a, Figures 4 to 6 Both are exemplified by one first metal unit 222a, which is located at one side of the display area AA and surrounds part of the display area AA. Referring to Figures 4 to 6 As shown, the third metal structure 223 includes at least one second metal unit 223a. Figures 4 to 6 A second metal unit 223a is used as an example. The second metal unit 223a is located on one side of the display area AA and surrounds part of the display area AA, that is, a smaller number of first metal units 222a and second metal units 223a are set. This can reduce the process preparation cost of the metal wiring while ensuring that electrical signals are provided to the charge generation layer 330 and the second electrode layer 350.

[0067] Furthermore, the second metal structure 222 may further include a plurality of first metal units 222a, and the third metal structure 223 may further include a plurality of second metal units 223a. Figure 7 In the figure, four first metal units 222a and four second metal units 223a are used as examples to illustrate that the four first metal units 222a surround the display area AA, and the four second metal units 223a surround the display area AA. This can ensure that the signal transmitted to the charge generation layer 330 and the second electrode layer 350 is better, thereby ensuring the overall display effect of the display panel.

[0068] Continue to refer Figures 4 to 7 As shown, the first metal unit 222a and the second metal unit 223a are located on the same side or different sides of the display area AA.

[0069] Specifically, refer to Figure 4 As shown, the first metal unit 222a and the second metal unit 223a are located on the same side of the display area AA, so that the first metal unit 222a and the second metal unit 223a only occupy the non-display area NA on one side of the display area AA, that is, the first metal unit 222a and the second metal unit 223a occupy a small amount of space, which can provide wiring space for other metal traces set in the non-display area NA, or can increase the space share of the display area AA in the entire display panel 10, thereby facilitating the realization of a narrow frame design of the display panel 10.

[0070] Specifically, refer to Figure 5 and Figure 6 As shown, the first metal unit 222a and the second metal unit 223a are located on different sides of the display area AA, and the different sides include relatively different sides (such as Figure 5 as shown) and the adjacent opposite side (as Figure 6 As shown), this ensures that the first metal unit 222a and the second metal unit 223a do not generate signal interference with each other when transmitting electrical signals, thereby ensuring the stability of each signal transmission and improving the overall display effect of the display panel 10.

[0071] For further reference, Figure 7As shown, in the case of multiple first metal units 222a and multiple second metal units 223a, the multiple first metal units 222a and the multiple second metal units 223a surround the display area AA, thereby ensuring the regularity of the wiring design in the display panel 10.

[0072] Continue to refer Figure 1 As shown, the second metal structure 222 includes a third metal unit 222b, which surrounds the display area AA; the third metal structure 223 includes a fourth metal unit 223b, which surrounds the third metal unit 222b.

[0073] Specifically, refer to Figure 1 As shown, the second metal structure 222 includes a third metal unit 222b, and the third metal unit 222b surrounds the display area AA. Figure 1 As shown, the third metal unit 222b can be understood as a ring-shaped metal structure. Similarly, the third metal structure 223 includes a fourth metal unit 223b, and the fourth metal unit 223b surrounds the third metal unit 222b. Figure 1 As shown, the fourth metal unit 223b can be understood as a ring-shaped metal structure.

[0074] Optional, combined Figure 1 and Figure 7 As shown, the annular third metal unit 222b can be understood as Figure 7 The annular metal structure is formed by electrically connecting multiple first metal units 222a end to end; the annular fourth metal unit 223b can be understood as Figure 7 The annular metal structure formed by electrically connecting multiple second metal units 223a end to end can ensure the regular design of the metal routing while also ensuring better signal transmission to the charge generation layer 330 and the second electrode layer 350, thereby ensuring the overall display effect of the display panel.

[0075] Figure 8 yes Figure 1 Another cross-sectional diagram along the section line A-A', Figure 9 yes Figure 1 Another cross-sectional diagram along the section line A-A', refer to Figure 1 、 Figure 2 、 Figure 8 and Figure 9 As shown, the first metal structure 221 , the second metal structure 222 and the third metal structure 223 are arranged on the same layer.

[0076] Specifically, refer to Figure 1As shown, the first metal structure 221, the second metal structure 222, and the third metal structure 223 in the array layer 200 are arranged in the same layer. This can reduce the film thickness of the display panel 10, which is beneficial to achieving a thin design of the display panel 10. Optionally, if the space reserved for metal wiring in the same layer is small due to the high ppi requirements of the display panel 10, the first metal structure 221, the second metal structure 222, and the third metal structure 223 can also be arranged in different layers. Based on the fact that the first metal structure 221, the second metal structure 222, and the third metal structure 223 are arranged in different layers, the specific film layer locations can be adaptively adjusted according to needs, and this embodiment of the present invention does not specifically limit this.

[0077] For further reference, Figure 9 As shown, the first metal structure 221 can be reused as the first electrode layer 310, and the second metal structure 222 and the third metal structure 223 are arranged on the same layer as the first electrode layer 310. This can further reduce the overall film thickness of the display panel 10, which is beneficial to achieving a thin design of the display panel 10.

[0078] Optionally, the side of the light emitting element 300 away from the substrate 100 may further include an encapsulation layer (specifically shown in the figure), that is, the display panel 10 can adaptively increase or decrease film layers according to needs, which is not specifically described in the embodiment of the present invention.

[0079] Based on the same inventive concept, an embodiment of the present invention provides a method for manufacturing a display panel. Figure 10 is a flow chart of a method for manufacturing a display panel provided by an embodiment of the present invention, with reference to Figure 10 As shown, the preparation method includes:

[0080] S110 , providing a substrate.

[0081] S120, preparing an array layer.

[0082] The display panel includes a display area, in which light-emitting elements, which are subsequently fabricated, are disposed. The display function of the display panel is achieved by driving the light-emitting elements to emit light. The display panel also includes a non-display area, which surrounds at least a portion of the display area. The specific locations of the display and non-display areas are not specifically limited in this embodiment of the present invention. The display panel also includes a display controller, such as a driver chip, disposed in the non-display area NA. Signals transmitted by the display controller can drive the light-emitting elements to emit light, thereby ensuring the display quality of the display panel 10.

[0083] Specifically, the display panel includes an array layer located on one side of a substrate. The array layer is used to drive subsequently fabricated light-emitting elements to produce light-emitting displays, thereby realizing the display function of the display panel. The multiple light-emitting elements in the display panel can be arranged in different ways, and the specific arrangements of the light-emitting elements are not described in detail in the embodiments of the present invention.

[0084] Specifically, the array layer includes a drive circuit, and the light-emitting elements of the display panel are electrically connected to the drive circuit. The drive circuit drives the light-emitting elements to achieve the light-emitting effect of the display panel. Specifically, the drive circuit includes at least one transistor, which is electrically connected to the light-emitting element and provides drive current to the subsequently fabricated light-emitting element, thereby ensuring normal display of the display panel. Furthermore, the drive circuit may include "4T1C," "7T1C," and "8T1C," where "T" represents a transistor and "C" represents a capacitor. Furthermore, the array layer includes multiple stacked film layers, such as a gate insulation layer, an interlayer insulation layer, a first planarization layer, a second planarization layer, and a pixel definition layer. The specific type and number of film layers in the array layer can be adaptively adjusted according to different requirements and are not specifically limited in this embodiment of the present invention. Furthermore, the transistors of the drive circuit include: an active layer, a gate, a drain, and a source. The specific configuration of the transistors can also be adaptively adjusted according to requirements and are not specifically limited in this embodiment of the present invention.

[0085] Furthermore, the array layer also includes a metal connection structure, which includes a first metal structure, a second metal structure, and a third metal structure, wherein the first metal structure is located in the display area, the second metal structure and the third metal structure are located in the non-display area, and the minimum distance between the orthographic projection of the second metal structure on the substrate and the display area is less than the minimum distance between the orthographic projection of the third metal structure on the substrate and the display area, that is, the second metal structure is closer to the display area AA than the third metal structure. At the same time, the first metal structure, the second metal structure, and the third metal structure transmit different electrical signals respectively, and the first metal structure, the second metal structure, and the third metal structure are insulated. If the first metal structure, the second metal structure, and the third metal structure are located in the same film layer, a one-step process can be used for synchronous etching preparation, thereby reducing the process preparation cost of the display panel.

[0086] S130 , sequentially preparing a first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer, and a second electrode layer of the light-emitting element.

[0087] The various film layers in the light-emitting element can be prepared by sequential evaporation. Specifically, the light-emitting element located on the side of the array layer away from the substrate includes multiple film layers, which, along the thickness direction of the display panel, sequentially include a first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer, and a second electrode layer, wherein the first electrode layer is located on the side of the first metal structure away from the substrate; the first common light-emitting layer is located on the side of the first electrode layer away from the array layer; the charge generation layer is located on the side of the first common light-emitting layer away from the first electrode layer; the second common light-emitting layer is located on the side of the charge generation layer away from the first common light-emitting layer; and the second electrode layer is located on the side of the second common light-emitting layer away from the charge generation layer.

[0088] Optionally, the first common light-emitting layer includes a first hole injection layer, a first hole transport layer, a first light-emitting layer, and a first electron transport layer; the first common light-emitting layer includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, and a second electron transport layer. Optionally, the first light-emitting layer is a red-green light-emitting layer, and the second light-emitting layer is a blue light-emitting layer. When a certain voltage is applied to each of the first and second electrode layers, holes from the first electrode layer can be injected into the hole transport layer through the hole injection layer and then transported to the light-emitting layer. Electrons from the second electrode layer can be transported to the light-emitting layer through the electron transport layer, forming excitons in the light-emitting layer. The excitons excite the light-emitting molecules in the light-emitting layer, causing them to emit light. A hole blocking layer can also be provided in the light-emitting element. The hole blocking layer is used to block holes from passing through the light-emitting layer and entering the electron transport layer, ensuring that holes and electrons combine in the light-emitting layer to form excitons, thereby ensuring the light-emitting effect of the light-emitting element. Furthermore, the light-emitting element is formed by stacking multiple light-emitting layers (i.e., the first and second light-emitting layers) in series via a charge generation layer (CGL). Among them, the tandem display panel can enable the light-emitting elements to be driven at the same current density, thereby greatly improving the brightness of the display panel. It can be understood that the light-emitting elements are tandem stacked light-emitting elements (Tandem), and the display panel can also be a tandem display panel (Tandem OLED).

[0089] Furthermore, the luminous effect of the light-emitting element will change as the voltage difference between the first electrode layer and the second electrode layer changes. In particular, when the voltage difference between the first electrode layer and the second electrode layer is small, the luminous effect of the second light-emitting layer in the light-emitting element will be worse than that of the first light-emitting layer. For example, when debugging the light-emitting element, the voltage difference between the first electrode layer and the second electrode layer will decrease at low grayscale, ultimately causing the voltage across the first common light-emitting layer and the second common light-emitting layer to change. Alternatively, it can be understood that when the voltage transmission path remains unchanged, the transmitted voltage difference is relatively small (the distance between the first electrode layer and the second electrode layer remains unchanged, but the voltage value decreases). Ultimately, more excitons are formed in the first light-emitting layer, while fewer excitons are formed in the second light-emitting layer. In order to ensure the luminous effect of the light-emitting element at low grayscale, the second metal structure is electrically connected to the charge generation layer between the first common light-emitting layer and the second common light-emitting layer, that is, the second metal structure provides an electrical signal to the charge generation layer, and adjusts the voltage value between the charge generation layer and the second electrode layer to ensure that sufficient excitons are formed in the second light-emitting layer, thereby improving the luminous effect of the light-emitting element at various voltages, thereby improving the overall display effect of the display panel.

[0090] Specifically, the first electrode layer is electrically connected to the driving circuit via a first metal structure, i.e., the driving signal generated by the driving circuit is transmitted to the first electrode layer via the first metal structure; the third metal structure is electrically connected to the second electrode layer, i.e., the fixed potential signal is transmitted to the second electrode layer via the third metal structure, thereby achieving a voltage difference between the first electrode layer and the second electrode layer, thereby enabling the display of the light-emitting element. As described above, to avoid the luminous effect of the light-emitting element at low grayscale, the charge generation layer is also fed with an electrical signal, and the second metal structure is provided to be electrically connected to the charge generation layer, thereby ensuring a stable voltage difference between the charge generation layer and the second electrode layer, thereby ensuring that the stacked light-emitting layers in the light-emitting element can generate sufficient excitons, thereby ensuring the display effect of the display panel.

[0091] In summary, the preparation method of the display panel provided by the embodiment of the present invention electrically connects the prepared second metal structure with the charge generation layer of the light-emitting element, and adjusts the deposition areas of the three groups when preparing the first common light-emitting layer, the charge generation layer and the second common light-emitting layer, so that the positive projection area of ​​the first common light-emitting layer in the light-emitting element to the substrate is S1, the positive projection area of ​​the charge generation layer to the substrate is S2, and the positive projection area of ​​the second common light-emitting layer to the substrate is S3; it satisfies: S1<S2<S3, ensuring that the charge generation layer is electrically connected to the second metal structure, and can be connected to the electrical signal when needed, thereby ensuring the luminous effect of the light-emitting element, and thereby improving the overall display effect of the display panel.

[0092] Figure 11is a flowchart of another display panel preparation method provided by an embodiment of the present application. The preparation method further includes:

[0093] S210, providing a substrate.

[0094] S220, preparing an array layer.

[0095] S230, preparing a first electrode layer.

[0096] S240, preparing a first common light-emitting layer using a first mask.

[0097] S250, preparing a charge generation layer using a second mask.

[0098] S260, preparing a second common light-emitting layer using a third mask.

[0099] S270, preparing a second electrode layer.

[0100] Further, a normal projection area of the first common light-emitting layer on the substrate is S1, and a normal projection area of the charge generation layer on the substrate is S2, where S1 < S2. The first common light-emitting layer includes multiple common film layers such as a first hole injection layer, a first hole transport layer, a first light-emitting layer, and a first electron transport layer, which can be prepared using the same mask, i.e., the first mask. The charge generation layer needs to be electrically connected to the second metal structure, and to avoid electrical connection between the charge generation layer and the first electrode layer, the charge generation layer is prepared using another mask, i.e., the second mask. The normal projection area of the first common light-emitting layer on the substrate is smaller than the normal projection area of the charge generation layer on the substrate. Similarly, to avoid electrical connection between the charge generation layer and the second electrode layer, the normal projection area of the charge generation layer on the substrate is adjusted to be smaller than the normal projection area of the second common light-emitting layer on the substrate, and the second common light-emitting layer is prepared using another mask, i.e., the third mask. That is, S1 < S2 < S3, so as to ensure the display effect of the display panel as a whole. That is, the opening size of the first mask is smaller than the opening size of the second mask, and the opening size of the second mask is smaller than the opening size of the third mask.

[0101] Further, to ensure electrical connection between the second electrode layer and the third metal structure, the second electrode layer can be prepared using a fourth mask when the second electrode layer is prepared, and the opening size of the third mask is smaller than the opening size of the fourth mask.

[0102] Based on the same inventive concept, an embodiment of the present application further provides a display device, Figure 12 is a structural schematic diagram of a display device provided by an embodiment of the present application, as shown in Figure 12As shown, the display device 1 includes the display panel 10 described in any of the above embodiments. Therefore, the display device 1 provided by the embodiment of the present invention has the corresponding beneficial effects of the above embodiments, which will not be repeated here. The display device 1 can be an electronic device such as a mobile phone, a computer, a smart wearable device (such as a smart watch), and an in-vehicle display device.

[0103] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A display panel, characterized in that: include: a display area and a non-display area, wherein the non-display area surrounds at least a portion of the display area; substrate; an array layer located on one side of the substrate; the array layer comprising a driving circuit and a metal connection structure, the metal connection structure comprising a first metal structure located in the display area and a second metal structure and a third metal structure located in the non-display area; the first metal structure is electrically connected to the driving circuit, and the first, second, and third metal structures are insulated from each other; and a minimum distance between an orthographic projection of the second metal structure onto the substrate and the display area is less than a minimum distance between an orthographic projection of the third metal structure onto the substrate and the display area. a light-emitting element located in the display area and on a side of the array layer away from the substrate, the light-emitting element comprising a first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer, and a second electrode layer; the first electrode layer being located on a side of the first metal structure away from the substrate; the first common light-emitting layer being located on a side of the first electrode layer away from the array layer; the charge generation layer being located on a side of the first common light-emitting layer away from the first electrode layer; the second common light-emitting layer being located on a side of the charge generation layer away from the first common light-emitting layer; and the second electrode layer being located on a side of the second common light-emitting layer away from the charge generation layer; The first electrode layer is electrically connected to the driving circuit via the first metal structure, the second metal structure is electrically connected to the charge generation layer, and the third metal structure is electrically connected to the second electrode layer; The orthographic projection area of ​​the first common light-emitting layer onto the substrate is S1, the orthographic projection area of ​​the charge generation layer onto the substrate is S2, and the orthographic projection area of ​​the second common light-emitting layer onto the substrate is S3; Satisfies: S1<S2<S3.

2. The display panel according to claim 1, wherein: The first common light-emitting layer includes a first light-emitting layer, and the second common light-emitting layer includes a second light-emitting layer; the light-on voltage of the first light-emitting layer is V1th, and the light-on voltage of the second light-emitting layer is V2th; The first metal structure provides a first voltage V1 for the first electrode layer; the third metal structure provides a second voltage V2 for the second electrode layer; When V1-V2<V1th+V2th+ΔV, the second metal structure provides a third voltage V3 to the charge generation layer; wherein ΔV is a preset adjustment voltage value.

3. The display panel according to claim 2, wherein: V1>V3>V2.

4. The display panel according to claim 1, wherein: The second metal structure includes at least one first metal unit; the first metal unit is located on one side of the display area and surrounds a portion of the display area; The third metal structure includes at least one second metal unit; the second metal unit is located on one side of the display area and surrounds a portion of the display area.

5. The display panel according to claim 4, wherein: The first metal unit and the second metal unit are located on the same side or different sides of the display area.

6. The display panel according to claim 1, wherein: The second metal structure includes a third metal unit, and the third metal unit surrounds the display area; The third metal structure includes a fourth metal unit, and the fourth metal unit surrounds the third metal unit.

7. The display panel according to claim 1, wherein: The first metal structure, the second metal structure and the third metal structure are arranged in the same layer.

8. A method for preparing a display panel, characterized in that: The display panel includes a display area and a non-display area, wherein the non-display area surrounds at least a portion of the display area; providing a substrate; An array layer is prepared, the array layer being located on one side of the substrate; the array layer comprising a driving circuit and a metal connection structure, the metal connection structure comprising a first metal structure located in the display area and a second metal structure and a third metal structure located in the non-display area; the first metal structure is electrically connected to the driving circuit, and the first, second, and third metal structures are insulated from each other; and the minimum distance between the orthographic projection of the second metal structure onto the substrate and the display area is less than the minimum distance between the orthographic projection of the third metal structure onto the substrate and the display area. A first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer and a second electrode layer of a light-emitting element are prepared in sequence; the first electrode layer is located on a side of the first metal structure away from the substrate; the first common light-emitting layer is located on a side of the first electrode layer away from the array layer, the charge generation layer is located on a side of the first common light-emitting layer away from the first electrode layer, the second common light-emitting layer is located on a side of the charge generation layer away from the first common light-emitting layer, and the second electrode layer is located on a side of the second common light-emitting layer away from the charge generation layer; the first electrode layer is electrically connected to the driving circuit through the first metal structure, the second metal structure is electrically connected to the charge generation layer, and the third metal structure is electrically connected to the second electrode layer; wherein the orthographic projection area of ​​the first common light-emitting layer onto the substrate is S1, the orthographic projection area of ​​the charge generation layer onto the substrate is S2, and the orthographic projection area of ​​the second common light-emitting layer onto the substrate is S3; Satisfies: S1<S2<S3.

9. The preparation method according to claim 8, characterized in that Sequentially preparing a first electrode layer, a first common light-emitting layer, a charge generation layer, a second common light-emitting layer, and a second electrode layer of a light-emitting element includes: preparing a first electrode layer; Using a first mask to prepare a first common light-emitting layer; preparing a charge generation layer using a second mask; A second common light-emitting layer is prepared using a third mask; wherein the opening size of the first mask is smaller than the opening size of the second mask, and the opening size of the second mask is smaller than the opening size of the third mask; A second electrode layer is prepared.

10. A display device, characterized in that: The display panel comprises the display panel according to any one of claims 1 to 7.

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