Display panel, preparation method thereof and display device

Abstract

The invention provides a display panel, a preparation method thereof and a display device. The display panel includes: a driving substrate; a plurality of anode electrodes; the first functional layer comprises a first light-emitting lamination layer, a second light-emitting lamination layer and a third light-emitting lamination layer; the first cathode electrode is arranged on the first light-emitting lamination layer and the second light-emitting lamination layer; the charge generation layer is arranged on the third light-emitting lamination layer and the first cathode electrode; the second functional layer comprises a fourth light-emitting lamination layer, the fourth light-emitting lamination layer is arranged on the charge generation layer, the orthographic projection of the fourth light-emitting lamination layer on the first functional layer covers the first light-emitting lamination layer, the second light-emitting lamination layer and the third light-emitting lamination layer, and the fourth light-emitting lamination layer and the third light-emitting lamination layer have the same color; and the second cathode electrode is arranged on the second functional layer, and the orthographic projection of the second cathode electrode on the first functional layer coincides with the third light-emitting laminated layer. According to the display panel, the cost is reduced and the product yield is improved on the basis of the light-emitting device with the laminated series structure.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display panel and a manufacturing method thereof, and a display device. Background Art

[0002] As the demands of end-user customers continue to increase, the requirements for display technology are also getting higher and higher. In order to meet the growing needs of users, various new technologies have emerged, including the popular color optimization technology (Color Optimization Engine, COE), micro lens array (Micro Lens Array, MLA) integration technology, eLEAP technology, and tandem technology. In particular, the tandem device structure can not only reduce power consumption, but also greatly increase the life of each red / green / blue (R / G / B) device to meet the needs of medium-sized products. However, the efficiency and life of the blue single structure (Single) device are still low, and the performance needs to be improved through the tandem structure (Tandem).

[0003] However, the stacked series structure requires more layers of fine metal mask (FMM) evaporation, which not only increases the cost but also reduces the product yield. Summary of the invention

[0004] The present application provides a display panel and a method for preparing the same, and a display device, aiming to solve the problem in the prior art that a light-emitting device with a stacked series structure requires more layers of FMM evaporation, resulting in increased costs and reduced product yield.

[0005] In order to solve the above technical problems, the first technical solution provided by the present application is to provide a display panel. The display panel includes:

[0006] Driver substrate;

[0007] A plurality of anode electrodes are distributed in an array on the driving substrate and are electrically connected to the driving substrate;

[0008] The first functional layer includes a first light-emitting stack, a second light-emitting stack and a third light-emitting stack, which are respectively arranged on corresponding anode electrodes;

[0009] A first cathode electrode is disposed on the first light-emitting stack and the second light-emitting stack;

[0010] The display panel further includes:

[0011] A charge generation layer is disposed on the third light emitting stack and the first cathode electrode;

[0012] The second functional layer includes a fourth light-emitting stack, which is disposed on the charge generation layer, and whose orthographic projection on the first functional layer covers the first light-emitting stack, the second light-emitting stack and the third light-emitting stack; the fourth light-emitting stack has the same color as the third light-emitting stack;

[0013] The second cathode electrode is disposed on the second functional layer, and the orthographic projection of the second cathode electrode on the first functional layer overlaps with the third light-emitting stack.

[0014] In some embodiments, the first light-emitting stack includes a red light-emitting layer, the second light-emitting stack includes a green light-emitting layer, the third light-emitting stack includes a first blue light-emitting layer, and the fourth light-emitting stack includes a second blue light-emitting layer.

[0015] In some embodiments, the first light-emitting stack further includes a first electron blocking layer between the anode electrode and the red light-emitting layer; the second light-emitting stack further includes a second electron blocking layer between the anode electrode and the green light-emitting layer; the third light-emitting stack further includes a third electron blocking layer between the anode electrode and the first blue light-emitting layer; the fourth light-emitting stack further includes a fourth electron blocking layer between the charge generation layer and the second blue light-emitting layer;

[0016] The first functional layer also includes a hole injection layer and a first hole transport layer stacked and located between the anode electrode and the first to third light-emitting stacks, and a first hole blocking layer and a first electron transport layer stacked and located between the first to third light-emitting stacks and the first cathode electrode;

[0017] The second functional layer further includes a second hole transport layer stacked between the charge generation layer and the fourth light-emitting stack, and a second hole blocking layer and a second electron transport layer stacked between the fourth light-emitting stack and the second cathode electrode.

[0018] In some embodiments, the display panel further includes an isolation structure, which is disposed on the driving substrate and has a plurality of pixel openings, wherein the pixel openings expose the first sub-pixel, the second sub-pixel, and the third sub-pixel;

[0019] The first sub-pixel includes a first light emitting stack and a corresponding anode electrode and a corresponding first cathode electrode, as well as a portion of the charge generation layer and a portion of the fourth light emitting stack located in the corresponding pixel opening;

[0020] The second sub-pixel includes a second light-emitting stack and a corresponding anode electrode and a corresponding first cathode electrode, as well as a portion of the charge generation layer and a portion of the fourth light-emitting stack located in the corresponding pixel opening;

[0021] The third sub-pixel includes a third light emitting stack and a corresponding anode electrode, a fourth light emitting stack, and a portion of the charge generation layer and a second cathode electrode located in the pixel opening.

[0022] In order to solve the above technical problems, the second technical solution provided by the present application is to provide a method for preparing a display panel. The preparation method comprises:

[0023] Providing a prefabricated board, the prefabricated board comprising a driving substrate and a plurality of anode electrodes disposed on the driving substrate, wherein the anode electrodes are electrically connected to the driving substrate;

[0024] Making a first functional layer on the prefabricated board; the first functional layer comprises a first light-emitting stack, a second light-emitting stack and a third light-emitting stack respectively formed on corresponding anode electrodes;

[0025] A first cathode electrode is fabricated on the first functional layer; the first cathode electrode is formed on the first light-emitting stack and the second light-emitting stack;

[0026] forming a charge generation layer on the first cathode electrode and the third light emitting stack;

[0027] A second functional layer is formed on the charge generation layer; the second functional layer includes a fourth light-emitting stack, the projection of the fourth light-emitting stack on the first functional layer covers the first light-emitting stack, the second light-emitting stack and the third light-emitting stack, and the fourth light-emitting stack has the same color as the third light-emitting stack;

[0028] A second cathode electrode is manufactured on the second functional layer; and the second cathode electrode is formed on the third light-emitting stack.

[0029] In some embodiments, in the step of forming a charge generation layer on the first cathode electrode and the third light-emitting stack, and in the step of forming a second functional layer on the charge generation layer, both are formed by evaporation through a cathode mask.

[0030] In some embodiments, the step of forming a first cathode electrode on the first functional layer includes:

[0031] By performing evaporation through a first cathode mask matching the first cathode electrode, a first cathode electrode is deposited on the first light-emitting stack and the second light-emitting stack to form the first cathode electrode; or,

[0032] Performing evaporation through a cathode mask to deposit a first cathode layer on the first light-emitting stack, the second light-emitting stack, and the third light-emitting stack;

[0033] Forming a first photoresist layer by coating on the first cathode layer, and patterning the first photoresist layer to expose a portion of the first cathode layer on the third light-emitting stack;

[0034] removing a portion of the first cathode layer on the third light-emitting stack;

[0035] The first photoresist layer is removed.

[0036] In some embodiments, the step of fabricating a second cathode electrode on the second functional layer includes:

[0037] By evaporating a second cathode mask matched with the second cathode electrode, a second cathode electrode is deposited at a corresponding position on the third light-emitting stack to form the second cathode electrode; or,

[0038] Performing evaporation through a cathode mask to deposit a second cathode layer at corresponding positions on the first light-emitting stack, the second light-emitting stack, and the third light-emitting stack;

[0039] Forming a second photoresist layer on the second cathode layer by coating, and patterning the second photoresist layer to expose a portion of the second cathode layer above the first light-emitting stack and the second light-emitting stack;

[0040] removing a portion of the second cathode layer above the first light-emitting stack and the second light-emitting stack;

[0041] The second photoresist layer is removed.

[0042] In some embodiments, the step of fabricating a second cathode electrode on the second functional layer includes:

[0043] By performing evaporation through a first cathode mask matched with the first cathode electrode, a cathode barrier layer is deposited at corresponding positions on the first light-emitting stack and the second light-emitting stack; the cathode barrier layer repels the gold cathode material;

[0044] The cathode material is evaporated to form a second cathode electrode at a position above the third light-emitting stack.

[0045] In order to solve the above technical problems, the third technical solution provided by the present application is to provide a display device. The display device includes:

[0046] The display panel is the display panel provided by the above technical solution;

[0047] The control circuit board is electrically connected to the display panel and is used to control the display panel to display corresponding images.

[0048] Beneficial effects of the present application: Different from the prior art, the present application provides a display panel, a method for preparing the same, and a display device. The display panel includes a driving substrate, a plurality of anode electrodes, a first functional layer, a first cathode electrode, a charge generation layer, a second functional layer, and a second cathode electrode. Among them, the first functional layer includes a first light-emitting stack, a second light-emitting stack, and a third light-emitting stack, which are respectively arranged on the corresponding anode electrodes, and the first electrode is arranged on the first light-emitting stack and the second light-emitting stack to form a single-structure first light-emitting device and a second light-emitting device. Further, by making the charge generation layer arranged on the third light-emitting stack and the first cathode electrode, the second functional layer includes a fourth light-emitting stack, the fourth light-emitting stack is arranged on the charge generation layer, the second cathode electrode is arranged on the second functional layer, and the positive projection of the second cathode electrode on the first functional layer coincides with the third light-emitting stack, so that the third light-emitting stack overlaps with the fourth light-emitting stack through the charge generation layer to form a light-emitting device of a series structure, and by making the colors of the third light-emitting stack and the fourth light-emitting stack the same, the light-emitting efficiency and life of the third light-emitting device can be effectively improved, and then the third light-emitting device can be made a blue light-emitting device, thereby improving the overall service life of the display panel. At the same time, by making the orthographic projection of the fourth light-emitting stack on the first functional layer cover the first light-emitting stack, the second light-emitting stack and the third light-emitting stack, that is, the pattern of the fourth light-emitting stack is the same as the cathode pattern, an open mask (Common Metal Mask, CMM) can be used for evaporation. Specifically, the fourth light-emitting stack can be made using a cathode mask, and there is no need to add a mask specifically for making the fourth light-emitting stack, and only at least 4 CMM evaporation times are required, which can reduce costs and improve product yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0050] Figure 1 is a schematic cross-sectional structure diagram of a display panel provided by an embodiment of the prior art;

[0051] Figure 2 is a schematic cross-sectional structural diagram of a display panel provided by an embodiment of the present application;

[0052] Figure 3 is a schematic cross-sectional structural diagram of a display panel provided by another embodiment of the present application;

[0053] Figure 4 is a schematic flow chart of a method for preparing a display panel provided in one embodiment of the present application;

[0054] Figure 5 It is a schematic flow chart of a method for preparing a first cathode electrode provided in one embodiment of the present application;

[0055] Figure 6 It is a schematic flow chart of a method for preparing a second cathode electrode provided in one embodiment of the present application;

[0056] Figure 7 is a schematic flow chart of a method for preparing a second cathode electrode provided in another embodiment of the present application;

[0057] Figure 8 It is a schematic diagram of the structure of a display device provided in one embodiment of the present application.

[0058] Reference numerals:

[0059] 100a, display panel; 10a, driving substrate; 21a, first light-emitting unit; 211a, first anode; 212a, first functional layer; 213a, second functional layer; 22a, second light-emitting unit; 221a, second anode; 222a, third functional layer; 223a, fourth functional layer; 23a, third light-emitting unit; 231a, third anode; 232a, fifth functional layer; 233a, sixth functional layer; 24a, charge generation layer; 25a, cathode;

[0060] 100, display panel; 10, drive substrate; 11, substrate; 12, drive circuit layer; 21, anode electrode; 22, first functional layer; 221, hole injection layer; 222, first hole transport layer; 223, first light-emitting stack; 2231, first electron blocking layer; 2232, red light-emitting layer; 224, second light-emitting stack; 2241, second electron blocking layer; 2242, green light-emitting layer; 225, third light-emitting stack; 2251, third electron blocking layer; 2252, first blue light-emitting layer; 226, first hole blocking layer; 227, third light-emitting stack; 2281, third electron blocking layer; 2282, first blue light-emitting layer; 2283, first hole blocking layer; 2284, second electron blocking layer; 2285, third light-emitting stack; 2286, third electron blocking layer; 2287, third light-emitting layer; 2288, third electron blocking layer; 2289, third electron blocking layer; 2290, third electron blocking layer; 2301, third electron blocking layer; 2312, third electron blocking layer; 2323, third electron blocking layer; 2331, third electron blocking layer; 2332, third electron blocking layer; 2343, third electron blocking layer; 2354, third electron blocking layer; 2365, third electron blocking layer; 2376, third electron blocking layer; 2387, third electron blocking layer; 2391, third electron blocking layer; 2405, third electron blocking layer; 2414, third electron blocking layer; 2415, third electron blocking layer; 2416, third electron blocking layer; 2417, third electron blocking layer; 2418, third electron blocking layer; 2419, third electron blocking layer; 2424, third electron blocking layer; An electron transport layer; 23, a first cathode electrode; 24, a charge generation layer; 241, an N-type charge generation layer; 242, a P-type charge generation layer; 25, a second functional layer; 251, a second hole transport layer; 252, a fourth light-emitting stack; 2521, a fourth electron blocking layer; 2522, a second blue light-emitting layer; 253, a second hole blocking layer; 254, a second electron transport layer; 26, a second cathode electrode; 27, an isolation structure; 271, a pixel opening; 200, a control circuit board; P1-a first sub-pixel; P2-a second sub-pixel; P3-a third sub-pixel. DETAILED DESCRIPTION

[0061] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0062] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0063] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] The terms "first", "second", "third" in this application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second", "third" can expressly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the embodiments of this application, all directional indications (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the steps or units listed, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0065] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0066] See also Figure 1 , Figure 1 1 is a schematic diagram of a cross-sectional structure of a display panel provided by an embodiment of the prior art. In the prior art, in order to improve the life of each light-emitting device on the display panel 100a and meet the requirements of medium-sized products, each light-emitting device is usually made into a stacked series structure. As shown in the figure, the display panel 100a includes a driving substrate 10a and a first light-emitting unit 21a, a second light-emitting unit 22a and a third light-emitting unit 23a arranged on the driving substrate 10a.

[0067] The first light emitting unit 21a includes a first anode 211a, a first functional layer 212a, a charge generating layer 24a, a second functional layer 213a and a cathode 25a stacked in sequence in a direction away from the driving substrate 10a. The first functional layer 212a and the second functional layer 213a both include a red light emitting layer.

[0068] The second light emitting unit 22a includes a second anode 221a, a third functional layer 222a, a charge generating layer 24a, a fourth functional layer 223a and a cathode 25a stacked in sequence in a direction away from the driving substrate 10a. The third functional layer 222a and the fourth functional layer 223a both include a green light emitting layer.

[0069] The third light emitting unit 23a includes a third anode 231a, a fifth functional layer 232a, a charge generating layer 24a, a sixth functional layer 233a and a cathode 25a stacked in sequence in a direction away from the driving substrate 10a. The fifth functional layer 232a and the sixth functional layer 233a both include a blue light emitting layer.

[0070] It can be seen that, through the above-mentioned arrangement of the first light-emitting unit 21a, the second light-emitting unit 22a and the third light-emitting unit 23a, the first light-emitting unit 21a, the second light-emitting unit 22a and the third light-emitting unit 23a form a stacked series structure light-emitting device, thereby increasing the life of each light-emitting device to meet the needs of medium-sized panels. However, compared with the traditional single-layer light-emitting layer structure light-emitting unit, the first light-emitting unit 21a, the second light-emitting unit 22a and the third light-emitting unit 23a of the stacked series structure require an additional process of a light-emitting functional layer for each color of the light-emitting unit, so more layers of FMM evaporation are required, which not only increases the product cost, but also easily reduces the product yield.

[0071] In order to solve the above technical problems, the embodiments of the present application propose a display panel and a method for manufacturing the same, and a display device, which will be described below for details.

[0072] The present application is described in detail below with reference to the accompanying drawings and embodiments.

[0073] See also Figure 2 , Figure 2 1 is a schematic diagram of a cross-sectional structure of a display panel provided in an embodiment of the present application. In this embodiment, a display panel 100 is provided, and the display panel 100 includes:

[0074] A driving substrate 10;

[0075] A plurality of anode electrodes 21 are distributed on the driving substrate 10 in an array and are electrically connected to the driving substrate 10;

[0076] The first functional layer 22 includes a first light-emitting stack 223, a second light-emitting stack 224 and a third light-emitting stack 225, which are respectively disposed on the corresponding anode electrodes 21;

[0077] A first cathode electrode 23 is disposed on the first light-emitting stack 223 and the second light-emitting stack 224;

[0078] The charge generation layer 24 is disposed on the third light emitting stack 225 and the first cathode electrode 23;

[0079] The second functional layer 25 includes a fourth light-emitting stack 252, which is disposed on the charge generation layer 24, and whose orthographic projection on the first functional layer 22 covers the first light-emitting stack 223, the second light-emitting stack 224 and the third light-emitting stack 225; the fourth light-emitting stack 252 has the same color as the third light-emitting stack 225;

[0080] The second cathode electrode 26 is disposed on the second functional layer 25 , and the orthographic projection of the second cathode electrode 26 on the first functional layer 22 coincides with the third light-emitting stack 225 .

[0081] The driving substrate 10 includes a substrate 11 and a driving circuit layer 12. The substrate 11 is used to carry the driving circuit layer 12 and each sub-pixel. The substrate 11 can be a glass substrate, a silicon substrate, or a flexible substrate, which can be set according to actual needs. The driving circuit layer 12 is arranged on the substrate 11, and the driving circuit layer 12 includes a plurality of sub-pixel driving circuits (not shown) for driving the sub-pixels to emit light. Specifically, the sub-pixel driving circuit is composed of at least one semiconductor driving device and at least one energy storage device, so as to provide a driving signal to the sub-pixel to drive the sub-pixel to emit light.

[0082] Among them, a plurality of anode electrodes 21 are distributed in an array on the driving substrate 10. The anode electrode 21 is arranged on the driving circuit layer 12 and is electrically connected to the corresponding sub-pixel driving circuit. The anode electrode 21 specifically serves as the anode of the sub-pixel. The material of the anode electrode 21 may include one of metals and metal oxides or a combination of the two; the metal material may be a metal conductive material such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), etc., and the metal oxide may be a metal oxide conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), etc. For example, the anode electrode 21 may be a multilayer structure of ITO layer-metal layer-ITO layer, which can be specifically arranged according to actual needs. The anode electrode 21 can be specifically formed by patterning through a patterning process, such as a patterning process such as a photolithography process or an evaporation process.

[0083] The first functional layer 22 is disposed on the anode electrode 21, that is, disposed on the side of the anode electrode 21 away from the driving substrate 10. The first functional layer 22 includes a first light-emitting stack 223, a second light-emitting stack 224 and a third light-emitting stack 225, which are respectively disposed on the corresponding anode electrode 21. Specifically, the first light-emitting stack 223 and the corresponding anode electrode 21 are used to form a first sub-pixel P1, the second light-emitting stack 224 and the corresponding anode electrode 21 are used to form a second sub-pixel P2, and the third light-emitting stack 225 and the corresponding anode electrode 21 are used to form a third sub-pixel P3.

[0084] It should be noted that on the display panel 100, the area where the first light-emitting stack 223 is located is used to form the first sub-pixel P1, the area where the second light-emitting stack 224 is located is used to form the second sub-pixel P2, and the area where the third light-emitting stack 225 is located is used to form the third sub-pixel P3.

[0085] Among them, the first cathode electrode 23 is arranged on one side of the source driving substrate 10 of the first functional layer 22. The first cathode electrode 23 is specifically arranged on the first light-emitting stack 223 and the second light-emitting stack 224, that is, the orthographic projection of the first cathode electrode 23 on the first functional layer 22 coincides with the first light-emitting stack 223 and the second light-emitting stack 224. In this way, the anode electrode 21, the first light-emitting stack 223 and other film layers of the first functional layer 22, and the first cathode electrode 23 located in the first sub-pixel P1 region constitute the first sub-pixel P1 with a single-layer light-emitting layer structure, and the anode electrode 21, the second light-emitting stack 224 and other film layers of the first functional layer 22, and the first cathode electrode 23 located in the second sub-pixel P2 region constitute the second sub-pixel P2 with a single-layer light-emitting structure. Specifically, the material of the first cathode electrode 23 may be a metal or alloy material; the metal material may be a metal conductive material with a low work function such as aluminum (Al), silver (Ag), lithium (Li), magnesium (Mg), calcium (Ca), indium (In), etc., to facilitate the injection of electrons; the alloy material may be an alloy of active low work function metals and relatively stable high work function metals such as magnesium-silver alloy (Mg:Ag) and lithium-aluminum alloy (Li:Al).

[0086] The charge generation layer 24 is disposed on the third light-emitting stack 225 and the first cathode electrode 23. Specifically, the charge generation layer 24 includes an N-type charge generation layer 241 and a P-type charge generation layer 242 that are stacked; wherein the N-type charge generation layer 241 has the function of generating electrons and transmitting electrons to the corresponding film layer, and the P-type charge generation layer 242 has the function of generating holes and transmitting holes to the corresponding film layer.

[0087] The second functional layer 25 is disposed on the charge generation layer 24, that is, disposed on the side of the charge generation layer 24 away from the driving substrate 10. The second functional layer 25 includes a fourth light-emitting stack 252, and the orthographic projection of the fourth light-emitting stack 252 on the first functional layer 22 covers the first light-emitting stack 223, the second light-emitting stack 224 and the third light-emitting stack 225. The charge generation layer 24 and the second functional layer 25 located in the first sub-pixel P1 region can be used as the light-emitting layer of the first sub-pixel P1, and the charge generation layer 24 and the second functional layer 25 located in the second sub-pixel P2 region can be used as the light-emitting layer of the second sub-pixel P2, and the light-emitting layer can be used for dimming to improve the brightness of the first sub-pixel P1 and the second sub-pixel P2.

[0088] The second cathode electrode 26 is disposed on the second functional layer 25, and its orthographic projection on the first functional layer 22 coincides with the third light-emitting stack 225; that is, the second cathode electrode 26 is disposed in the third sub-pixel P3 region to form the third sub-pixel P3 with each functional film layer located in the third pixel region. In the third sub-pixel P3 region, the second cathode electrode 26 and the second functional layer 25 are connected in series with the first functional layer 22 and the anode electrode 21 through the charge generation layer 24 to form a third sub-pixel P3 of a series structure, and the color of the fourth light-emitting stack 252 is the same as the color of the third light-emitting stack 225, thereby improving the brightness of the luminous efficiency of the third sub-pixel P3, so as to improve the life of the third sub-pixel P3. Furthermore, the third sub-pixel P3 can also be a blue sub-pixel, which can improve the luminous efficiency and life of the blue sub-pixel, thereby improving the overall service life of the display panel 100.

[0089] In this embodiment, through the above arrangement, the orthographic projection of the fourth light-emitting stack 252 on the first functional layer 22 covers the first light-emitting stack 223, the second light-emitting stack 224 and the third light-emitting stack 225, that is, the pattern of the fourth light-emitting stack 252 is the same as the cathode pattern, and can be produced by common metal mask (Common Metal Mask, CMM) evaporation. Specifically, the fourth light-emitting stack 252 can be produced by using a cathode mask, and there is no need to add a mask specifically used for producing the fourth light-emitting stack 252, which can reduce product costs. Moreover, since the series structure only needs to be produced by CMM evaporation on the fourth light-emitting stack 252, only at least 4 CMM evaporations are required, and there is no need to evaporation on light-emitting stacks of other colors after etching, which reduces costs and improves product yields.

[0090] In some embodiments, the first light-emitting stack 223 includes a red light-emitting layer 2232 , the second light-emitting stack 224 includes a green light-emitting layer 2242 , the third light-emitting stack 225 includes a first blue light-emitting layer 2252 , and the fourth light-emitting stack 252 includes a second blue light-emitting layer 2522 .

[0091] Specifically, the first light-emitting stack 223 is located in the first sub-pixel P1 area, the second light-emitting stack 224 is located in the second sub-pixel P2 area, and the third light-emitting stack 225 and the fourth light-emitting stack 252 are located in the third sub-pixel P3 area; that is, the first sub-pixel P1 is a red sub-pixel, the second sub-pixel P2 is a green sub-pixel, and the third sub-pixel P3 is a blue sub-pixel, so that the blue sub-pixel is a light-emitting device with a series structure, and the red sub-pixel and the green sub-pixel are light-emitting devices with a single-layer light-emitting structure, thereby improving the luminous efficiency and lifespan of the blue sub-pixel, so that the lifespan of the blue sub-pixel is closer to and more balanced with the lifespan of the red sub-pixel and the green sub-pixel, thereby improving the impact of the low luminous efficiency and lifespan of the blue sub-pixel on the overall service life of the display panel 100.

[0092] In some embodiments, the first light-emitting stack 223 also includes a first electron blocking layer 2231 located between the anode electrode 21 and the red light-emitting layer 2232; the second light-emitting stack 224 also includes a second electron blocking layer 2241 located between the anode electrode 21 and the green light-emitting layer 2242; the third light-emitting stack 225 also includes a third electron blocking layer 2251 located between the anode electrode 21 and the first blue light-emitting layer 2252; the fourth light-emitting stack 252 also includes a fourth electron blocking layer 2521 located between the charge generation layer 24 and the second blue light-emitting layer 2522.

[0093] The first functional layer 22 also includes a hole injection layer 221 and a first hole transport layer 222 which are stacked and located between the anode electrode 21 and the first light-emitting stack 223 to the third light-emitting stack 225, and a first hole blocking layer 226 and a first electron transport layer 227 which are stacked and located between the first light-emitting stack 223 to the third light-emitting stack 225 and the first cathode electrode 23.

[0094] The second functional layer 25 further includes a second hole transport layer 251 stacked between the charge generation layer 24 and the fourth light-emitting stack 252 , and a second hole blocking layer 253 and a second electron transport layer 254 stacked between the fourth light-emitting stack 252 and the second cathode electrode 26 .

[0095] That is, in the first functional layer 22, the three sub-pixels share the hole injection layer 221, the first hole transport layer 222, the first hole blocking layer 226 and the first electron transport layer 227. Considering the microcavity effect of the first sub-pixel P1, the second sub-pixel P2 and the third sub-pixel P3, in order to make the light color of each sub-pixel meet the product luminescence requirements, the thickness of the first hole transport layer 222 can be correspondingly thinned, and the thickness of the first electron blocking layer 2231 and the second electron blocking layer 2241 can be correspondingly thickened. The specific thinning size and thickening size can be determined according to the spectral requirements, so as to adjust the position of the microcavity and the intensity of the microcavity effect, so that the light color meets the product requirements.

[0096] Among them, the second hole transport layer 251, the fourth electron blocking layer 2521, the second blue light-emitting layer 2522, the second hole blocking layer 253 and the second electron transport layer 254 of the second functional layer 25 can all be formed by sequential evaporation deposition by the CMM method to reduce the number of evaporation times, reduce the difficulty of process production, and improve product yield.

[0097] In some embodiments, the first functional film layer may not include the first hole transport layer 222, the first electron blocking layer 2231, the second electron blocking layer 2241, the third electron blocking layer 2251, the first hole blocking layer 226 and the first electron transport layer 227, and may be specifically configured according to actual needs. The second functional film layer may not include the second hole transport layer 251, the fourth electron blocking layer 2521, the second hole blocking layer 253 and the second electron transport layer 254, and may be specifically configured according to needs.

[0098] See also Figure 3 , Figure 3 2 is a schematic diagram of a cross-sectional structure of a display panel provided in another embodiment of the present application. In this embodiment, the display panel 100 further includes an isolation structure 27, which is disposed on the drive substrate 10 and has a plurality of pixel openings 271, and the pixel openings 271 expose the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3.

[0099] The first sub-pixel P1 includes a first light-emitting stack 223 and a corresponding anode electrode 21 and a corresponding first cathode electrode 23, as well as a portion of the charge generation layer 24 and a portion of the fourth light-emitting stack 252 located in the corresponding pixel opening 271; the second sub-pixel P2 includes a second light-emitting stack 224 and a corresponding anode electrode 21 and a corresponding first cathode electrode 23, as well as a portion of the charge generation layer 24 and a portion of the fourth light-emitting stack 252 located in the corresponding pixel opening 271; the third sub-pixel P3 includes a third light-emitting stack 225 and a corresponding anode electrode 21, a fourth light-emitting stack 252, as well as a portion of the charge generation layer 24 and a second cathode electrode 26 located in the pixel opening 271.

[0100] Specifically, an isolation structure 27 is also provided on the driving substrate 10. By making the isolation structure 27 have multiple pixel openings 271, and making the pixel openings 271 expose the first sub-pixel P1, the second sub-pixel P2 and the third sub-pixel P3, the isolation structure 27 separates sub-pixels of different colors to avoid lateral crosstalk between sub-pixels of different colors.

[0101] Specifically, when preparing the display panel 100, the anode electrode 21 may be first formed on the driving substrate 10, and then the isolation structure 27 may be formed on the driving substrate 10 by a patterning process, wherein the isolation structure 27 has a plurality of pixel openings 271, and the pixel openings 271 expose each anode electrode 21. After the isolation structure 27 is first formed on the driving substrate 10, when the light-emitting layers of each color are subsequently evaporated, the isolation structure 27 may play a blocking role to separate light-emitting layers of different colors, thereby preventing light-emitting layers of different colors from overlapping and causing cross-color problems.

[0102] In some embodiments, the isolation structure 27 may include a pixel definition layer, which may be formed by a photolithography patterning process. The specific shape of the pixel definition layer may be set according to actual needs, for example, the shape in the longitudinal section may be a rectangle, a regular trapezoid, or an inverted trapezoid, which may be set according to the production process and is not specifically limited thereto.

[0103] In some embodiments, the display panel 100 further includes a sealing layer, which is disposed on the second functional layer 25 and the second cathode electrode 26, and can be used to encapsulate the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3, and can also serve as a light emitting layer for the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3. Specifically, the sealing layer can be an inorganic insulating layer, and the refractive index of the sealing layer can be controlled by arranging sealing layers with different compositions, thereby further adjusting the light emitting direction and light emitting brightness of the first sub-pixel P1, the second sub-pixel P2, and the third sub-pixel P3, thereby improving the display effect of the display panel 100.

[0104] The display panel 100 provided in the above embodiment can be prepared by using the manufacturing method provided in the following implementation mode. Please refer to the following introduction for details.

[0105] See also Figure 4 , Figure 4 1 is a schematic diagram of a method for preparing a display panel according to an embodiment of the present application. In this embodiment, a method for preparing a display panel 100 is provided, and the method comprises:

[0106] S1: providing a prefabricated board, wherein the prefabricated board includes a driving substrate 10 and a plurality of anode electrodes 21 disposed on the driving substrate 10, and the anode electrodes 21 are electrically connected to the driving substrate 10;

[0107] S2: manufacturing a first functional layer 22 on the prefabricated board; the first functional layer 22 comprises a first light-emitting stack 223, a second light-emitting stack 224 and a third light-emitting stack 225 respectively formed on the corresponding anode electrodes 21;

[0108] S3: manufacturing a first cathode electrode 23 on the first functional layer 22; the first cathode electrode 23 is formed on the first light-emitting stack 223 and the second light-emitting stack 224;

[0109] S4: forming a charge generation layer 24 on the first cathode electrode 23 and the third light-emitting stack 225;

[0110] S5: forming a second functional layer 25 on the charge generation layer 24; the second functional layer 25 comprises a fourth light-emitting stack 252, the projection of the fourth light-emitting stack 252 on the first functional layer 22 covers the first light-emitting stack 223, the second light-emitting stack 224 and the third light-emitting stack 225, and the fourth light-emitting stack 252 has the same color as the third light-emitting stack 225;

[0111] S6: manufacturing a second cathode electrode 26 on the second functional layer 25 ; the second cathode electrode 26 is formed on the third light-emitting stack 225 .

[0112] Among them, in step S2, specifically, the hole injection layer 221 and the first hole transport layer 222 can be formed by evaporation deposition in sequence on the prefabricated plate, and the evaporation can be performed using a cathode mask, or the evaporation deposition can be performed directly on the entire surface to form the hole injection layer 221 and the first hole transport layer 222 on the entire surface. Then, the first electron blocking layer 2231 and the red light-emitting layer 2232, the second electron blocking layer 2241 and the green light-emitting layer 2242, the third electron blocking layer 2251 and the first blue light-emitting layer 2252 are formed by evaporation deposition respectively through the masks corresponding to the light-emitting layers of each color. After that, the first hole blocking layer 226 and the first electron blocking layer 2231 are formed by evaporation deposition in sequence, and the evaporation can be performed using a cathode mask, or the evaporation can be performed directly on the entire surface to deposit and form the first hole blocking layer 226 and the first electron transport layer 227 on the entire surface. Thereby, the production of the first functional layer 22 is completed.

[0113] In step S3, the first cathode electrode 23 is prepared by an evaporation process, so that the first cathode electrode 23 is formed on the first light-emitting stack 223 and the second light-emitting stack 224, thereby forming a first light-emitting device and a second light-emitting device of a single-layer light-emitting structure.

[0114] In step S4 , an N-type charge generation layer 241 and a P-type charge generation layer 242 are sequentially formed by an evaporation process to prepare a charge generation layer 24 as a connection structure of the series structure in the third sub-pixel P3 .

[0115] In step S5, the second hole transport layer 251, the fourth electron blocking layer 2521, the second blue light-emitting layer 2522, the second hole blocking layer 253 and the second electron transport layer 254 can be formed by sequentially evaporating and depositing on the charge generation layer 24, thereby completing the production of the second functional layer 25. Specifically, each film layer of the second functional layer 25 can be formed by evaporating and depositing using a cathode mask, without the need for an additional special mask, thereby reducing the production cost of the product; and reducing the number of evaporation times, thereby simplifying the process and effectively improving the yield of the product.

[0116] In step S6, a second cathode electrode 26 is formed on the second functional layer 25 by evaporation or photolithography. The second cathode electrode 26 is formed in the third sub-pixel P3 region, thereby forming a complete third sub-pixel P3 in series structure in the third sub-pixel P3 region.

[0117] The display panel 100 manufactured by the above manufacturing method can effectively improve the luminous efficiency and life of the third sub-pixel P3. If the third sub-pixel P3 is a blue sub-pixel, the luminous efficiency and life of the blue sub-pixel can be effectively improved, thereby making the life of the blue sub-pixel closer to that of the red sub-pixel and the green sub-pixel, thereby improving the service life of the display panel 100. At the same time, by using the above manufacturing method to manufacture the display panel 100, the manufacturing cost can be reduced, the manufacturing process can be simplified, and the product yield can be improved.

[0118] In some embodiments, in step S4 of forming the charge generation layer 24 on the first cathode electrode 23 and the third light-emitting stack 225, and in step S5 of forming the second functional layer 25 on the charge generation layer 24, both are formed by evaporation through a cathode mask. In this way, there is no need to add a special mask to form the charge generation layer 24 and the second functional layer 25, which can save the production cost of the display panel 100.

[0119] In some embodiments, step S3 of making the first cathode electrode 23 on the first functional layer 22 includes: performing evaporation through a first cathode mask matching the first cathode electrode 23 to deposit the first cathode electrode 23 on the first light-emitting stack 223 and the second light-emitting stack 224 .

[0120] That is, when manufacturing the first cathode electrode 23, a first cathode mask matching the first cathode electrode 23 can be used, and specifically, the first cathode electrode 23 can be formed by deposition using an FMM evaporation method. It should be noted that, in order to reduce the problem of Ag metal high temperature process damaging the mask, the material of the first cathode electrode 23 can use a CEM low temperature process material, i.e., a material used in a chemical vapor deposition process that is polar at a temperature that is higher but lower than the melting point of the substrate, and specifically, the process temperature can be around 600°C.

[0121] See also Figure 5 , Figure 5 : is a schematic flow chart of a method for preparing a first cathode electrode provided in one embodiment of the present application. In some embodiments, step S3 may specifically include the following steps:

[0122] S31: performing evaporation through a cathode mask to deposit a first cathode layer on the first light-emitting stack 223, the second light-emitting stack 224 and the third light-emitting stack 225;

[0123] S32: coating a first photoresist layer on the first cathode layer, and patterning the first photoresist layer to expose a portion of the first cathode layer on the third light-emitting stack 225;

[0124] S33: removing a portion of the first cathode layer on the third light-emitting stack 225;

[0125] S34: removing the first photoresist layer.

[0126] In some embodiments, a cathode mask can be used for evaporation to form a first cathode layer on the entire surface, and then a portion of the first cathode layer located in the third sub-pixel P3 region can be removed by etching to form the first cathode electrode 23 described in the above embodiment. It should be noted that in order to reduce the impact of the etching process on the underlying organic film layer, the underlying first electron transport layer 227 can be made of an etching-resistant material. By using this manufacturing method to manufacture the first cathode electrode 23, there is no need to prepare an additional FMM that matches the pattern of the first cathode electrode 23, so as to save manufacturing costs.

[0127] In some embodiments, step S6 of making the second cathode electrode 26 on the second functional layer 25 includes: performing evaporation through a second cathode 26 mask plate matching the second cathode electrode 26 to deposit the second cathode electrode 26 at a corresponding position on the third light-emitting stack 225 .

[0128] That is, similar to the first cathode electrode 23, a second cathode 26 mask matching the second cathode electrode 26 can be used, and specifically, it can be formed by deposition using an FMM evaporation method. It should be noted that in order to reduce the problem of Ag metal high temperature process damaging the mask, the material of the second cathode electrode 26 can use a CEM low temperature process material, that is, a material used in a chemical vapor deposition process that is polar at a temperature that is higher but lower than the melting point of the substrate, and specifically, the process temperature can be around 600°C.

[0129] See also Figure 6 , Figure 6 : is a schematic flow chart of a method for preparing a second cathode electrode provided in one embodiment of the present application. In some embodiments, step S6 may specifically include the following steps:

[0130] S61: performing evaporation through a cathode mask to deposit a second cathode 26 layer at corresponding positions on the first light-emitting stack 223 , the second light-emitting stack 224 , and the third light-emitting stack 225 ;

[0131] S62: coating a second photoresist layer on the second cathode layer 26, and patterning the second photoresist layer to expose a portion of the second cathode layer 26 above the first light-emitting stack 223 and the second light-emitting stack 224;

[0132] S63: removing a portion of the second cathode 26 layer on the first light-emitting stack 223 and the second light-emitting stack 224;

[0133] S64: removing the second photoresist layer.

[0134] and Figure 5 The implementation is similar. In some embodiments, a cathode mask can be used for evaporation to form a second cathode 26 layer on the entire surface, and then a portion of the second cathode 26 layer located in the first sub-pixel P1 region and the second sub-pixel P2 region is removed by etching to form the second cathode electrode 26 described in the above embodiment. It should be noted that in order to reduce the impact of the etching process on the underlying organic film layer, the underlying second electron transport layer 254 can be made of an etching-resistant material. By using this manufacturing method to manufacture the second cathode electrode 26, there is no need to prepare an additional FMM that matches the pattern of the second cathode electrode 26, so as to save manufacturing costs.

[0135] See also Figure 7 , Figure 7 FIG. 5 is a flow chart of a method for preparing a second cathode electrode provided in another embodiment of the present application. In some embodiments, step S6 may specifically include the following steps:

[0136] S65: performing evaporation through a first cathode mask matched with the first cathode electrode 23 to deposit a cathode barrier layer at corresponding positions on the first light-emitting stack 223 and the second light-emitting stack 224; the cathode barrier layer repels the cathode material;

[0137] S66 : Evaporating a cathode material to form a second cathode electrode 26 on the third light-emitting stack 225 .

[0138] Among them, the cathode blocking layer repels the cathode material, so that the cathode material cannot adhere to the cathode blocking layer. Therefore, after the cathode blocking layer is first deposited in the first sub-pixel area and the second sub-pixel area, when the cathode material is evaporated, the cathode material cannot be deposited in the first sub-pixel area and the second sub-pixel area, but can only be deposited in the third sub-pixel area, thereby forming a second cathode electrode 26.

[0139] Among them, the cathode material may specifically include a metal material, and the material of the cathode barrier layer may be a cathode patterning material (CPM). The CPM material is incompatible with the metal material and repel each other, so that the cathode barrier layer formed by the CPM material and the cathode material repel each other. In some embodiments, the CPM material is a fluorine-containing organic material, such as a substituted fluorinated cyclotriphosphazene compound. The CPM material can be deposited in the first sub-pixel area and the second sub-pixel area by low-temperature vacuum evaporation to form the above-mentioned cathode barrier layer. In other embodiments, the CPM material may not be a fluorine-containing organic material, as long as the CPM material and the metal material are incompatible with each other and repel each other.

[0140] See also Figure 8 , Figure 8 1 is a schematic diagram of a display device according to an embodiment of the present application. In this embodiment, a display device is provided, and a display device is provided, which can be used in display fields such as tablets, mobile phones, vehicles, VR glasses, and lighting equipment.

[0141] The display device includes a display panel 100 and a control circuit board 200. The control circuit board 200 is electrically connected to the display panel 100, and is used to provide the display panel 100 with various drive signals, power signals and other drive signals required by the display panel 100, so as to control the display panel 100 to display corresponding images. The specific structure and function of the display panel 100 are the same or similar to the specific structure and function of the display panel 100 in the above embodiment, and the same technical effect can be achieved, and the specific reference can be made to the above related introduction.

[0142] The above are only implementation methods of the present application, and are not intended to limit the patent protection scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A display panel, comprising: Driver substrate; A plurality of anode electrodes are distributed in an array on the driving substrate and are electrically connected to the driving substrate; The first functional layer includes a first light-emitting stack, a second light-emitting stack and a third light-emitting stack, which are respectively arranged on the corresponding anode electrodes; A first cathode electrode, disposed on the first light-emitting stack and the second light-emitting stack; Characterized in that the display panel further comprises: A charge generation layer, disposed on the third light-emitting stack and the first cathode electrode; A second functional layer, comprising a fourth light-emitting stack, wherein the fourth light-emitting stack is disposed on the charge generation layer, and an orthographic projection of the fourth light-emitting stack on the first functional layer covers the first light-emitting stack, the second light-emitting stack and the third light-emitting stack; the fourth light-emitting stack has the same color as the third light-emitting stack; The second cathode electrode is disposed on the second functional layer, and the orthographic projection of the second cathode electrode on the first functional layer overlaps with the third light-emitting stack.

2. The display panel according to claim 1, characterized in that: The first light-emitting stack includes a red light-emitting layer, the second light-emitting stack includes a green light-emitting layer, the third light-emitting stack includes a first blue light-emitting layer, and the fourth light-emitting stack includes a second blue light-emitting layer.

3. The display panel according to claim 2, characterized in that: The first light-emitting stack further includes a first electron blocking layer located between the anode electrode and the red light-emitting layer; the second light-emitting stack further includes a second electron blocking layer located between the anode electrode and the green light-emitting layer; the third light-emitting stack further includes a third electron blocking layer located between the anode electrode and the first blue light-emitting layer; the fourth light-emitting stack further includes a fourth electron blocking layer located between the charge generation layer and the second blue light-emitting layer; The first functional layer further includes a hole injection layer and a first hole transport layer stacked and located between the anode electrode and the first to third light-emitting stacks, and a first hole blocking layer and a first electron transport layer stacked and located between the first to third light-emitting stacks and the first cathode electrode; The second functional layer further includes a second hole transport layer stacked between the charge generation layer and the fourth light-emitting stack, and a second hole blocking layer and a second electron transport layer stacked between the fourth light-emitting stack and the second cathode electrode.

4. The display panel according to claim 1, characterized in that: The display panel further includes an isolation structure, which is disposed on the drive substrate and has a plurality of pixel openings, wherein the pixel openings expose the first sub-pixel, the second sub-pixel, and the third sub-pixel; The first sub-pixel includes the first light-emitting stack and the corresponding anode electrode and the corresponding first cathode electrode, as well as a portion of the charge generation layer and a portion of the fourth light-emitting stack located in the corresponding pixel opening; The second sub-pixel includes the second light-emitting stack and the corresponding anode electrode and the corresponding first cathode electrode, as well as a portion of the charge generation layer and a portion of the fourth light-emitting stack located in the corresponding pixel opening; The third sub-pixel includes the third light-emitting stack and the corresponding anode electrode, the fourth light-emitting stack, and a portion of the charge generation layer and the second cathode electrode located in the pixel opening.

5. A method for preparing a display panel, characterized in that: include: Providing a prefabricated board, the prefabricated board comprising a driving substrate and a plurality of anode electrodes disposed on the driving substrate, wherein the anode electrodes are electrically connected to the driving substrate; A first functional layer is fabricated on the prefabricated plate; the first functional layer comprises a first light-emitting stack, a second light-emitting stack and a third light-emitting stack respectively formed on the corresponding anode electrodes; forming a first cathode electrode on the first functional layer; The first cathode electrode is formed on the first light emitting stack and the second light emitting stack; forming a charge generation layer on the first cathode electrode and the third light emitting stack; A second functional layer is formed on the charge generation layer; the second functional layer includes a fourth light-emitting stack, the projection of the fourth light-emitting stack on the first functional layer covers the first light-emitting stack, the second light-emitting stack and the third light-emitting stack, and the fourth light-emitting stack has the same color as the third light-emitting stack; forming a second cathode electrode on the second functional layer; The second cathode electrode is formed on the third light emitting stack.

6. The method for preparing a display panel according to claim 5, characterized in that: In the step of manufacturing a charge generation layer on the first cathode electrode and the third light-emitting stack, and in the step of manufacturing a second functional layer on the charge generation layer, both are formed by evaporation through a cathode mask.

7. The method for preparing a display panel according to claim 5, characterized in that: The step of manufacturing a first cathode electrode on the first functional layer comprises: The first cathode electrode is formed by depositing on the first light-emitting stack and the second light-emitting stack by evaporating through a first cathode mask matched with the first cathode electrode; or, Performing evaporation through a cathode mask to deposit a first cathode layer on the first light-emitting stack, the second light-emitting stack, and the third light-emitting stack; Forming a first photoresist layer by coating on the first cathode layer, and patterning the first photoresist layer to expose a portion of the first cathode layer on the third light-emitting stack; removing a portion of the first cathode layer on the third light-emitting stack; The first photoresist layer is removed.

8. The method for preparing a display panel according to claim 5, characterized in that: The step of manufacturing a second cathode electrode on the second functional layer comprises: By performing evaporation through a second cathode mask matching the second cathode electrode, the second cathode electrode is deposited at a corresponding position on the third light-emitting stack to form the second cathode electrode; or, Performing evaporation through a cathode mask to deposit a second cathode layer at corresponding positions on the first light-emitting stack, the second light-emitting stack, and the third light-emitting stack; Forming a second photoresist layer by coating on the second cathode layer, and patterning the second photoresist layer to expose a portion of the second cathode layer above the first light-emitting stack and the second light-emitting stack; removing a portion of the second cathode layer above the first light-emitting stack and the second light-emitting stack; The second photoresist layer is removed.

9. The method for preparing a display panel according to claim 5, characterized in that: The step of manufacturing the second cathode electrode on the second functional layer comprises: Depositing a cathode barrier layer at corresponding positions on the first light-emitting stack and the second light-emitting stack by evaporating a first cathode mask matched with the first cathode electrode; the cathode barrier layer repels the cathode material; The cathode material is evaporated to form the second cathode electrode at a position above the third light-emitting stack.

10. A display device, characterized in that: include: The display panel is a display panel as claimed in any one of claims 1 to 4; The control circuit board is electrically connected to the display panel and is used to control the display panel to display corresponding images.

Images