Display panel, preparation method thereof and display device

Abstract

The application provides a display panel, comprising a substrate, and a first electrode layer, a first film layer, a first light-emitting layer, a second film layer, a third film layer, a second light-emitting layer, a fourth film layer and a second electrode layer which are sequentially stacked on the substrate in a first direction perpendicular to the substrate and away from the substrate. The maximum value of the thickness of each light-emitting area of the first light-emitting layer and each light-emitting area of the second light-emitting layer in the first direction is greater than or equal to the thickness of at least three of the auxiliary film layers in the first direction; and / or the minimum value of the thickness of each light-emitting area of the first light-emitting layer and each light-emitting area of the second light-emitting layer in the first direction is less than or equal to the thickness of at least three of the auxiliary film layers in the first direction, and greater than the absolute value of the difference between the thickness of the first film layer and the fourth film layer in the first direction. The light-emitting spectrum, efficiency and service life of the light-emitting element can be optimized.

Description

TECHNICAL FIELD

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

[0002] Compared with the traditional liquid crystal display, the organic light-emitting diode (OLED) device has the advantages of self-illumination, light weight, wide viewing angle, fast response speed, low temperature resistance, high luminous efficiency and the like, and is considered as the most potential display device in the industry.

[0003] Therefore, the tandem OLED emerges as the times require in the development of OLED. The tandem OLED has the advantage of high brightness. However, the tandem OLED in the related art has the problems of serious deviation of brightness and chrominance under different viewing angles, large difference in RGB three-color life or low light extraction efficiency. SUMMARY

[0004] The present application proposes a display panel, a manufacturing method thereof and a display device to solve the technical problems of serious deviation of brightness and chrominance under different viewing angles, large difference in RGB three-color life or low light extraction efficiency of the display panel in the prior art.

[0005] According to a first aspect of an embodiment of the present application, a display panel is provided. The display panel comprises a substrate, and a first electrode layer, a first film layer, a first light-emitting layer, a second film layer, a third film layer, a second light-emitting layer, a fourth film layer and a second electrode layer which are sequentially stacked on a surface of the substrate along a first direction perpendicular to the substrate and away from the surface of the substrate;

[0006] The display panel comprises at least one first light-emitting element, at least one second light-emitting element and at least one third light-emitting element which are arranged in an array on the surface of the substrate along a second direction perpendicular to the first direction;

[0007] The first light-emitting element, the second light-emitting element and the third light-emitting element each comprise the first light-emitting layer and the second light-emitting layer, and at least share any one or more of the first film layer, the second film layer, the third film layer and the fourth film layer;

[0008] The first light-emitting element, the second light-emitting element and the third light-emitting element sequentially correspond to a first light-emitting area, a second light-emitting area and a third light-emitting area in orthographic projection on the surface of the substrate;

[0009] A maximum value of thickness of each light emitting region of the first light emitting layer and each light emitting region of the second light emitting layer in the first direction is greater than or equal to thickness of at least three of the first film layer, the second film layer, the third film layer, and the fourth film layer in the first direction; and / or, a minimum value of thickness of each light emitting region of the first light emitting layer and each light emitting region of the second light emitting layer in the first direction is less than or equal to thickness of at least three of the first film layer, the second film layer, the third film layer, and the fourth film layer in the first direction, and greater than an absolute value of a difference between thickness of the first film layer and thickness of the fourth film layer in the first direction.

[0010] According to the above embodiment, the display panel provided by the embodiment can increase the light emitting brightness of the display substrate by stacking a plurality of film layers assisting in forming the micro-cavity effect on both sides of the first light emitting layer and the second light emitting layer of the display panel. Meanwhile, the thickness ratio relationship in the first direction between each auxiliary film layer and each light emitting region of each light emitting layer is limited and matched, the micro-cavity effect is formed between the first electrode layer and the second electrode layer, the thickness between each auxiliary film layer and the light emitting layer is matched, the light emitting efficiency and the spectrum between the first light emitting layer and the second light emitting layer of the same light emitting element are coordinated, and the problem of double peaks in the spectrum is avoided. The spectrum of the light emitted by the first light emitting layer and the second light emitting layer can be optimized, the light emitting efficiency can be improved, and the service life of the light emitting device can be prolonged.

[0011] In addition, the embodiment maximizes the film layer structure in the display panel to set the film layer shared by the first light emitting element, the second light emitting element, and the third light emitting element, which can significantly reduce the number of fine metal masks (FMM) used, thereby reducing material costs and processing costs.

[0012] In one embodiment, the emission spectrum wavelength of the first light emitting element is less than the emission spectrum wavelength of the second light emitting element, and the emission spectrum wavelength of the second light emitting element is less than the emission spectrum wavelength of the third light emitting element.

[0013] In one embodiment, the thickness of any one of the first film layer, the second film layer, the third film layer, and the fourth film layer in the first direction is C i , C i satisfies:

[0014]

[0015] wherein n is a non-negative integer, and λ1 is the emission spectrum wavelength of the first light emitting element.

[0016] In one embodiment, thicknesses of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction are C1, C2, C3, C4 in sequence, respectively, and C1, C2, C3, C4 satisfy:

[0017] mλ3≤(C3+C4)≤(m+1)λ3

[0018] wherein m is a non-negative integer, and λ3 is a wavelength of an emission spectrum of the third light emitting element.

[0019] In one embodiment, the thickness of the third film layer in the first direction is greater than the thickness of the fourth film layer in the first direction, the thickness of the fourth film layer in the first direction is greater than the thickness of the first film layer in the first direction, and the thickness of the first film layer in the first direction is greater than the thickness of the second film layer in the first direction.

[0020] In one embodiment, a ratio of the thickness of the fourth film layer in the first direction to the thickness of the third film layer in the first direction is greater than or equal to 0.3 and less than or equal to 0.8, and a ratio of the thickness of the second film layer in the first direction to the thickness of the first film layer in the first direction is greater than or equal to 0.3 and less than or equal to 0.8.

[0021] In one embodiment, an absolute value of a difference between the thickness of the fourth film layer in the first direction and the thickness of the first film layer in the first direction is less than 10 nm.

[0022] In one embodiment, a light emitting area of the first light emitting element is greater than a light emitting area of the second light emitting element, and the light emitting area of the second light emitting element is greater than a light emitting area of the third light emitting element.

[0023] In one embodiment, a ratio of the light emitting area of the second light emitting element to the light emitting area of the third light emitting element is less than 1.6, and a ratio of the light emitting area of the first light emitting element to the light emitting area of the third light emitting element is less than 2.5.

[0024] In one embodiment, an absolute value of a difference between a wavelength corresponding to a peak of an emission spectrum of the first light emitting region of the first light emitting layer and a wavelength corresponding to a peak of an emission spectrum of the first light emitting region of the second light emitting layer is less than 5 nm.

[0025] In one embodiment, an absolute value of a difference between a wavelength corresponding to a peak of an emission spectrum of the second light emitting region of the first light emitting layer and a wavelength corresponding to a peak of an emission spectrum of the second light emitting region of the second light emitting layer is less than 5 nm.

[0026] In one embodiment, the absolute value of the difference between the wavelength corresponding to the peak of the emission spectrum of the third light-emitting region of the first light-emitting layer and the wavelength corresponding to the peak of the emission spectrum of the third light-emitting region of the second light-emitting layer is less than 5 nm.

[0027] In one embodiment, the first light-emitting layer comprises a first auxiliary light-emitting layer and a first main light-emitting layer which are sequentially stacked along the first direction; the first auxiliary light-emitting layer is at least partially disposed in at least any one of the first light-emitting region, the second light-emitting region and the third light-emitting region.

[0028] In one embodiment, the second light-emitting layer comprises a second auxiliary light-emitting layer and a second main light-emitting layer which are sequentially stacked along the first direction; the second auxiliary light-emitting layer is at least partially disposed in at least any one of the first light-emitting region, the second light-emitting region and the third light-emitting region.

[0029] In one embodiment, the first film layer comprises a first hole injection layer, a first hole transport layer and a first exciton blocking layer which are sequentially stacked on the substrate surface along the first direction.

[0030] In one embodiment, the second film layer comprises a second exciton blocking layer, a first electron transport layer and a first electron injection layer which are sequentially stacked on the substrate surface along the first direction.

[0031] In one embodiment, the third film layer comprises a second hole injection layer, a second hole transport layer and a third exciton blocking layer which are sequentially stacked on the substrate surface along the first direction.

[0032] In one embodiment, the fourth film layer comprises a fourth exciton blocking layer, a second electron transport layer and a second electron injection layer which are sequentially stacked on the substrate surface along the first direction.

[0033] According to a second aspect of embodiments of the present application, a preparation method of a display panel comprising the first aspect of embodiments of the present application is provided, comprising the following steps:

[0034] providing a substrate;

[0035] sequentially forming a first electrode layer, a first film layer, a first light-emitting layer, a second film layer, a third film layer, a second light-emitting layer, a fourth film layer and a second electrode layer on the substrate;

[0036] The display panel comprises at least one first light-emitting element, at least one second light-emitting element and at least one third light-emitting element which are arrayed on the substrate surface along the second direction; the second direction is perpendicular to the first direction.

[0037] The first light emitting element, the second light emitting element and the third light emitting element each include the first light emitting layer and the second light emitting layer, and at least share any one or more of the first film layer, the second film layer, the third film layer and the fourth film layer;

[0038] The first light emitting element, the second light emitting element and the third light emitting element have orthographic projections on the substrate plate surface corresponding to the first light emitting area, the second light emitting area and the third light emitting area in sequence;

[0039] The maximum value of the thickness of each light emitting area of the first light emitting layer and each light emitting area of the second light emitting layer in the first direction is greater than or equal to the thickness of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction;

[0040] The minimum value of the thickness of each light emitting area of the first light emitting layer and each light emitting area of the second light emitting layer in the first direction is less than or equal to the thickness of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction, and greater than the absolute value of the difference between the thickness of the first film layer and the fourth film layer in the first direction.

[0041] According to the above embodiment, in the display panel preparation process, by maximizing the sharing of each auxiliary film layer by the first light emitting element, the second light emitting element and the third light emitting element, the number of fine metal mask (FMM) used in the preparation process can be significantly reduced, thereby reducing the material cost and processing cost.

[0042] In one embodiment, the sequentially forming the first electrode layer, the first film layer, the first light emitting layer, the second film layer, the third film layer, the second light emitting layer, the fourth film layer and the second electrode layer on the substrate comprises:

[0043] Forming the first electrode layer on the substrate by using a photomask plate;

[0044] Forming the first film layer on the first electrode layer by using an open mask plate;

[0045] Sequentially forming the first light emitting layer on the first light emitting area, the second light emitting area and the third light emitting area of the substrate by using a fine metal mask;

[0046] Sequentially forming the second film layer and the third film layer on the first light emitting layer by using an open mask plate;

[0047] The second light-emitting layer is formed on the substrate by using a fine metal mask in sequence on the first light-emitting area, the second light-emitting area and the third light-emitting area of the substrate.

[0048] The fourth film layer and the second electrode layer are formed on the second light-emitting layer by using an open mask in sequence.

[0049] According to a third aspect of the embodiments of the present application, a display device including the display panel of the first aspect of the embodiments of the present application is provided.

[0050] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0052] Figure 1 is a structural schematic diagram of a display panel of an embodiment provided by the present application;

[0053] Figure 2 is a structural schematic diagram of a display panel of another embodiment provided by the present application;

[0054] Figure 3 is a pixel arrangement structure diagram of a display panel of an embodiment provided by the present application;

[0055] Figure 4 is a spectral curve diagram of a first light-emitting element of an embodiment provided by the present application;

[0056] Figure 5 is a spectral curve diagram of a second light-emitting element of an embodiment provided by the present application;

[0057] Figure 6 is a spectral curve diagram of a third light-emitting element of an embodiment provided by the present application.

[0058] In the drawings:

[0059] 1 - substrate; 21 - first electrode layer;

[0060] 22 - first film layer; 221 - first hole injection layer; 222 - first hole transport layer; 223 - first exciton blocking layer;

[0061] 23 - first light-emitting layer; 231 - first auxiliary light-emitting layer; 232 - first main light-emitting layer;

[0062] 24 - second film layer; 241 - second exciton-blocking layer; 242 - first electron-transporting layer; 243 - first electron-injecting layer;

[0063] 25 - third film layer; 251 - second hole-injecting layer; 252 - second hole-transporting layer; 253 - third exciton-blocking layer;

[0064] 26 - second light-emitting layer; 261 - second auxiliary light-emitting layer; 262 - second main light-emitting layer;

[0065] 27 - fourth film layer; 271 - fourth exciton-blocking layer; 272 - second electron-transporting layer; 273 - second electron-injecting layer;

[0066] 28 - second electrode layer;

[0067] 201 - first light-emitting element; 202 - second light-emitting element; 203 - third light-emitting element;

[0068] 201a - first light-emitting region; 202a - second light-emitting region; 203a - third light-emitting region. DETAILED DESCRIPTION

[0069] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The description herein relates to the drawings, in which the same numbers in different drawings represent the same or similar elements throughout. The following exemplary embodiments described in this specification encompass all devices and methods in accordance with the present application, as detailed in the appended claims. Conversely, they are merely examples of apparatus and methods in accordance with some aspects of the present application, as detailed in the appended claims.

[0070] The terminology used in this specification has been chosen as merely for the purpose of describing particular embodiments and is not intended to limit the application. As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the content clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0071] The research and development idea of the present application includes: the existing OLED device adopts a single light-emitting layer, and a scheme of separately evaporating RGB (red, green and blue) is adopted, but limited by the upper limit of the OLED light-emitting material itself, therefore, when applied to a high-brightness application scene such as a vehicle, a multi-light-emitting layer superposition scheme is often used to improve the light-emitting efficiency and increase the brightness. However, after the multi-light-emitting layer is superimposed, many problems will inevitably be derived, for example: 1. The spectrum in the light-emitting layer is superimposed to be wide, which causes the color purity to decrease, and under the action of the microcavity interference, the brightness and chromaticity under different viewing angles seriously deviate; 2. The efficiency of the OLED RGB three colors itself has a large difference, and the efficiency and life difference caused by the multi-light-emitting layer superposition is amplified, thereby accelerating the imbalance of the RGB three colors, causing the screen to turn yellow and other problems.

[0072] The display panel provided by the present application and the preparation method thereof and the display device are aimed at solving the above technical problems of the prior art.

[0073] The display panel and the preparation method thereof and the display device are described in detail below with reference to the accompanying drawings. In the case of no conflict, the features in the following embodiments can be complementary or combined with each other.

[0074] According to a first aspect of the present application, a display panel is provided. As shown in the figure, Figure 1 The display panel includes a substrate 1, and a first electrode layer 21, a first film layer 22, a first light-emitting layer 23, a second film layer 24, a third film layer 25, a second light-emitting layer 26, a fourth film layer 27 and a second electrode layer 28 which are sequentially stacked on the surface of the substrate 1 along a first direction perpendicular to the surface of the substrate 1 and away from the surface of the substrate 1;

[0075] The display panel includes at least one first light-emitting element 201, at least one second light-emitting element 202 and at least one third light-emitting element 203 which are arrayed on the surface of the substrate 1 along a second direction perpendicular to the first direction;

[0076] The first light-emitting element 201, the second light-emitting element 202 and the third light-emitting element 203 each include the first light-emitting layer 23 and the second light-emitting layer 26, and at least share any one or several layers of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27;

[0077] The first light-emitting element 201, the second light-emitting element 202 and the third light-emitting element 203 correspond to a first light-emitting area 201a, a second light-emitting area 202a and a third light-emitting area 203a in sequence in the orthographic projection on the surface of the substrate 1;

[0078] The maximum value of the thickness of each light emitting region of the first light emitting layer 23 and each light emitting region of the second light emitting layer 26 in the first direction is greater than or equal to the thickness of at least three of the first film layer 22, the second film layer 24, the third film layer 25, and the fourth film layer 27 in the first direction, respectively; and / or, the minimum value of the thickness of each light emitting region of the first light emitting layer 23 and each light emitting region of the second light emitting layer 26 in the first direction is less than or equal to the thickness of at least three of the first film layer 22, the second film layer 24, the third film layer 25, and the fourth film layer 27 in the first direction, respectively, and greater than the absolute value of the difference between the thickness of the first film layer 22 and the fourth film layer 27 in the first direction.

[0079] According to the above embodiment, the display panel provided by the embodiment can increase the light emitting brightness of the display panel by stacking a plurality of auxiliary film layers on both sides of the first light emitting layer 23 and the second light emitting layer 26 of the display panel, so that the first light emitting layer 23 and the second light emitting layer 26 form a series light emitting device. At the same time, the thickness ratio relationship in the first direction between each auxiliary film layer and each light emitting region of each light emitting layer is limited and matched, so that the microcavity effect is formed between the first electrode layer 21 and the second electrode layer 28, the thickness between each auxiliary film layer and the light emitting layer is matched, the light emitting efficiency and the spectrum between the first light emitting layer 23 and the second light emitting layer 26 of the same light emitting element are coordinated, and the problem of double peaks in the spectrum is avoided. The spectrum of the light emitted by the first light emitting layer 23 and the second light emitting layer 26 can be optimized, the light emitting efficiency can be improved, and the service life of the light emitting device can be prolonged.

[0080] In addition, the embodiment maximizes the film layer structure in the display panel to set the auxiliary film layer shared by the first light emitting element 201, the second light emitting element 202, and the third light emitting element 203, which can significantly reduce the number of fine metal masks (Fine Metal Mask, FMM) used, thereby reducing the material cost and the processing cost.

[0081] In some examples, the display panel is a bottom emission display panel. The first electrode layer 21 is a transmissive electrode that can transmit light, for example, an anode; and the second electrode layer 28 is a reflective electrode that can reflect light, for example, a cathode. A microcavity structure is formed between the anode and the cathode.

[0082] In other examples, the display panel is a top emission display panel. The first electrode layer 21 is a reflective electrode that can reflect light, for example, an anode; and the second electrode layer 28 is a transmissive electrode that can transmit light, for example, a cathode. A microcavity structure is formed between the anode and the cathode.

[0083] In some embodiments, the first electrode layer 21 can include a material with a high work function, and can be made of a transparent conductive oxide material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or IGZO (Indium Gallium Zinc Oxide), etc. when used in a bottom emission structure. The thickness of the first electrode layer 21 in the first direction can be in the range of 80 nm to 200 nm. When used in a top emission structure, a composite structure of a transparent oxide layer such as Ag / ITO or Ag / IZO can be used, in which the thickness of the metal layer in the first direction can be in the range of 80 nm to 100 nm, and the thickness of the metal oxide in the first direction can be in the range of 5 nm to 10 nm. In addition, the average reflectivity of the first electrode layer 21 for visible light can be in the range of 85% to 95%.

[0084] In some embodiments, the second electrode layer 28 can be made of a metal material such as Mg (magnesium), Ag (silver), or Al (aluminum), or an alloy material such as Mg:Ag. Preferably, if the alloy material Mg:Ag is used, the ratio between the Mg element and the Ag element can be in the range of 3:7 to 1:9. When used in a top emission structure, the thickness of the second electrode layer 28 in the first direction can be in the range of 10 nm to 20 nm, and the light transmittance for light with a wavelength of 530 nm can be in the range of 50% to 60%. When used in a bottom emission structure, the thickness of the second electrode layer 28 in the first direction can be greater than 80 nm, which can ensure that the second electrode has good reflectivity for light as a reflective structure.

[0085] It should be noted that the number of the first light emitting element 201, the second light emitting element 202, and the third light emitting element 203 can be n, where n is a positive integer. Those skilled in the art can design as needed according to actual conditions, which is not particularly limited here.

[0086] In one example, the number of the first light emitting element 201, the second light emitting element 202, and the third light emitting element 203 is 3.

[0087] It should be noted that the first light emitting element 201, the second light emitting element 202, and the third light emitting element 203 can share any one of the first film layer 22, the second film layer 24, the third film layer 25, and the fourth film layer 27, or can share all of the first film layer 22, the second film layer 24, the third film layer 25, and the fourth film layer 27. The more layers shared, the more the number of fine metal masks (FMM) used can be reduced. Those skilled in the art can freely choose.

[0088] In one example, the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 share the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27. This can achieve a maximum reduction in the number of Fine Metal Masks (FMM) used, thereby reducing material costs and processing costs.

[0089] In one example, the maximum thickness of the first light emitting layer 23 is the thickness of the first light emitting region 201a in the first direction, and the thickness of the first light emitting region 201a is greater than the thickness of the first film layer 22, the second film layer 24 and the third film layer 25 in the first direction, and is less than the thickness of the fourth film layer 27 in the first direction.

[0090] In another example, the minimum thickness of the first light emitting layer 23 is the thickness of the second light emitting region 202a in the first direction, and the thickness of the second light emitting region 202a is less than the thickness of the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction, and is greater than the absolute value of the difference between the thickness of the first film layer 22 and the thickness of the fourth film layer 27 in the first direction.

[0091] In yet another example, the maximum thickness of the first light emitting layer 23 is the thickness of the first light emitting region 201a in the first direction, and the thickness of the first light emitting region 201a is greater than the thickness of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction. The minimum thickness of the first light emitting layer 23 is the thickness of the third light emitting region 203a in the first direction, and the thickness of the third light emitting region 203a is less than the thickness of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction, and is greater than the absolute value of the difference between the thickness of the first film layer 22 and the thickness of the fourth film layer 27 in the first direction.

[0092] In some embodiments, the emission spectrum wavelength of the first light emitting element 201 is less than the emission spectrum wavelength of the second light emitting element 202, and the emission spectrum wavelength of the second light emitting element 202 is less than the emission spectrum wavelength of the third light emitting element 203.

[0093] In one example, the first light emitting element 201 is a blue light emitting element, the emission spectrum wavelength of which can be in the range of 400nm-500nm, for example 400nm, 450nm, 460nm, 470nm, 480nm or 500nm; the second light emitting element 202 is a green light emitting element, the emission spectrum wavelength of which can be in the range of 510nm-540nm, for example 510nm, 520nm, 530nm, 535nm or 540nm; and the third light emitting element 203 is a red light emitting element, the emission spectrum wavelength of which can be in the range of greater than 600nm, for example 600nm, 610nm, 650nm, 680nm or 700nm.

[0094] In some embodiments, the thickness of any one of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction is C i , C i satisfies:

[0095]

[0096] wherein n is a non-negative integer, and λ1 is the emission spectrum wavelength of the first light emitting element 201.

[0097] According to the above embodiments, by limiting the relationship between the thickness of each auxiliary film layer in the first direction and the emission spectrum wavelength of the first light emitting element 201, the matching microcavity structure can be adjusted, the thickness range interval of each auxiliary film layer in the first direction is obtained, the microcavity effect is formed between the anode and the cathode, the spectrum of the outgoing light is optimized, and the light emitting efficiency of the light emitting element is improved.

[0098] In some embodiments, n is 0, 1, 2 or 3. The lower the thickness of each auxiliary film layer, the higher the light extraction efficiency. λ1 can be in the range of 400nm-500nm, for example 400nm, 450nm, 460nm, 470nm, 480nm or 500nm.

[0099] In one example, n = 1, λ1 is 460nm, and 230nm ≤ C i ≤ 460nm. Specifically, the thickness of the first film layer 22 in the first direction is 250nm, the thickness of the second film layer 24 in the first direction is 230nm, the thickness of the third film layer 25 in the first direction is 400nm, and the thickness of the fourth film layer 27 in the first direction is 350nm.

[0100] In some embodiments, the thickness of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction is C1, C2, C3, C4 respectively, and C1, C2, C3, C4 satisfy:

[0101] mλ3≤(C3+C4)≤(m+1)λ3

[0102] wherein m is a non-negative integer, and λ3 is a wavelength of an emission spectrum of the third light-emitting element 203.

[0103] According to the above embodiments, by limiting the relationship between the sum of the thicknesses of the first film layer 22 and the second film layer 24 in the first direction and the sum of the thicknesses of the third film layer 25 and the fourth film layer 27 in the first direction, and the wavelength of the emission spectrum of the third light-emitting element 203, the microcavity structure can be adjusted, the microcavity effect between the anode and the cathode is formed, the spectrum of the outgoing light is optimized, and the light-emitting efficiency of the light-emitting element is improved.

[0104] In some embodiments, m is 0, 1, 2, or 3. The lower the thickness of each auxiliary film layer, the higher the light extraction efficiency. λ3 can be in a range greater than 600 nm, such as 600 nm, 610 nm, 650 nm, 680 nm, or 700 nm.

[0105] In one example, m = 1, λ3 is 640 nm, and 320 nm ≤ (C1+C2) ≤ 640 nm, 640 nm ≤ (C3+C4) ≤ 1280 nm. Specifically, the thickness of the first film layer 22 in the first direction is 260 nm, the thickness of the second film layer 24 in the first direction is 240 nm, the thickness of the third film layer 25 in the first direction is 500 nm, and the thickness of the fourth film layer 27 in the first direction is 400 nm.

[0106] In some embodiments, the thickness of the third film layer 25 in the first direction is greater than the thickness of the fourth film layer 27 in the first direction, the thickness of the fourth film layer 27 in the first direction is greater than the thickness of the first film layer 22 in the first direction, and the thickness of the first film layer 22 in the first direction is greater than the thickness of the second film layer 24 in the first direction.

[0107] According to the above embodiments, the thickness relationship between the auxiliary film layers in the first direction in the present embodiment is C3 > C4 > C1 > C2. On the one hand, C3 > C4 and C1 > C2 can achieve the transmission of the second electrode to the first light-emitting layer 23 and the second light-emitting layer 26, and the light emission of the first light-emitting layer 23 and the second light-emitting layer 26. On the other hand, C4 > C1 can enable the first light-emitting layer 23 and the second light-emitting layer 26 to be respectively arranged at the positions of the strongest light interference in the microcavity structure formed by the light-emitting device, thereby improving the light extraction efficiency of each light-emitting device and further improving the overall light extraction efficiency of the display panel.

[0108] In one example, the first film layer 22 has a thickness of 390 nm in the first direction, the second film layer 24 has a thickness of 380 nm in the first direction, the third film layer 25 has a thickness of 500 nm in the first direction, and the fourth film layer 27 has a thickness of 400 nm in the first direction.

[0109] In some embodiments, the ratio of the thickness of the fourth film layer 27 in the first direction to the thickness of the third film layer 25 in the first direction is greater than or equal to 0.3 and less than or equal to 0.8, and the ratio of the thickness of the second film layer 24 in the first direction to the thickness of the first film layer 22 in the first direction is greater than or equal to 0.3 and less than or equal to 0.8.

[0110] As can be seen from the above embodiments, further limiting the thickness ratio between each auxiliary film layer can further optimize the electron transport efficiency between film layers, improve the light emission efficiency and external quantum efficiency of the light-emitting element, and extend the lifespan of the light-emitting element.

[0111] In one example, the first film layer 22 has a thickness of 390 nm in the first direction, the second film layer 24 has a thickness of 312 nm in the first direction, the third film layer 25 has a thickness of 500 nm in the first direction, and the fourth film layer 27 has a thickness of 300 nm in the first direction.

[0112] In some embodiments, the absolute value of the difference between the thickness of the fourth film layer 27 and the first film layer 22 in the first direction is less than 10 nm.

[0113] As can be seen from the above embodiments, the thickness difference between the fourth film layer 27 and the first film layer 22 in this embodiment is less than 10nm, which can improve the uniformity of the light emitted by the first light-emitting layer 23 and the second light-emitting layer 26, thereby improving the matching degree between the light emitted by the first light-emitting element 201 and the second light-emitting element 202, and thus improving the light emission efficiency of the light-emitting element. Furthermore, the high matching degree between the first light-emitting element 201 and the second light-emitting element 202 can weaken the brightness and color deviation when the viewing angle changes.

[0114] In one example, the thickness of the fourth film layer 27 is 400 nm, the thickness of the first film layer 22 is 395 nm, and the absolute value of the difference between the thickness of the first film layer 22 in the first direction is less than 10 nm.

[0115] In some embodiments, such as Figure 3 As shown, the light-emitting area of ​​the first light-emitting element 201 is greater than that of the second light-emitting element 202, and the light-emitting area of ​​the second light-emitting element 202 is greater than that of the third light-emitting element 203.

[0116] According to the above embodiment, the light emitted by the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 is blue light, green light and red light respectively. Since the light emitting efficiency of the blue light emitting material is lower than that of the red light emitting material and the green light emitting material, the first light emitting element 201 can emit more blue light by increasing the light emitting area of the first light emitting element 201 corresponding to the blue light emitting material, so as to balance the red light and the green light and improve the display effect of the display panel. In addition, the stability of the blue light emitting material is poorer than that of the red light emitting material. Under a large current density, the light emitting device of the blue light emitting material decays faster. Increasing the light emitting area of the first light emitting element 201 can reduce the current density under the same voltage, delay the decay of the light emitting device, and further improve the efficiency and service life of the light emitting device.

[0117] In some embodiments, the ratio of the light emitting area of the second light emitting element 202 to the light emitting area of the third light emitting element 203 is less than 1.6, and the ratio of the light emitting area of the first light emitting element 201 to the light emitting area of the third light emitting element 203 is less than 2.5.

[0118] According to the above embodiment, the characteristics and decay rates of various light emitting materials are combined in this embodiment, and the basic requirements of RGB synthesized pixels are further combined to limit the proportional relationship between the light emitting areas of the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203, so as to keep the pixel density unchanged.

[0119] In some embodiments, the absolute value of the difference between the wavelength corresponding to the emission spectrum peak of the first light emitting area 201a of the first light emitting layer 23 and the wavelength corresponding to the emission spectrum peak of the first light emitting area 201a of the second light emitting layer 26 is less than 5 nm; and / or, the absolute value of the difference between the wavelength corresponding to the emission spectrum peak of the second light emitting area 202a of the first light emitting layer 23 and the wavelength corresponding to the emission spectrum peak of the second light emitting area 202a of the second light emitting layer 26 is less than 5 nm; and / or, the absolute value of the difference between the wavelength corresponding to the emission spectrum peak of the third light emitting area 203a of the first light emitting layer 23 and the wavelength corresponding to the emission spectrum peak of the third light emitting area 203a of the second light emitting layer 26 is less than 5 nm.

[0120] According to the above embodiment, each light emitting area corresponds to each light emitting element. For the light emitted by the two light emitting layers in the same light emitting element, the wavelengths corresponding to the emission spectrum peaks are similar or the same, which can improve the concentration of the spectral superposition of the two light emitting layers, improve the color purity and light emitting efficiency of the light.

[0121] In some embodiments, as Figure 2As shown, the first light-emitting layer 23 includes a first auxiliary light-emitting layer 231 and a first main light-emitting layer 232 stacked sequentially along a first direction; the first auxiliary light-emitting layer 231 is at least partially disposed in at least any one of the first light-emitting region 201a, the second light-emitting region 202a and the third light-emitting region 203a; and / or, the second light-emitting layer includes a second auxiliary light-emitting layer 261 and a second main light-emitting layer 262 stacked sequentially along a first direction; the second auxiliary light-emitting layer 261 is at least partially disposed in at least any one of the first light-emitting region 201a, the second light-emitting region 202a and the third light-emitting region 203a.

[0122] As can be seen from the above embodiments, by setting an auxiliary light-emitting layer on the side of either light-emitting region in the first light-emitting layer 23 and the second light-emitting layer 26 near the substrate 1, the thickness of the light-emitting layer can be adjusted, thereby adjusting the width of the emission spectrum and further optimizing the light extraction efficiency of the light-emitting element.

[0123] In one example, a first auxiliary light-emitting layer 231 is provided on the side of the first light-emitting region 201a of the first light-emitting layer 23 near the substrate 1, and a second auxiliary light-emitting layer 261 is provided on the side of the first light-emitting region 201a of the second light-emitting layer 26 near the substrate 1.

[0124] In some embodiments, such as Figure 2 As shown, the first film layer 22 includes a first hole injection layer 221, a first hole transport layer 222, and a first exciton blocking layer 223 sequentially stacked on the surface of the substrate 1 along a first direction; and / or, the second film layer 24 includes a second exciton blocking layer 241, a first electron transport layer 242, and a first electron injection layer 243 sequentially stacked on the surface of the substrate 1 along a first direction; and / or, the third film layer 25 includes a second hole injection layer 251, a second hole transport layer 252, and a third exciton blocking layer 253 sequentially stacked on the surface of the substrate 1 along a first direction; and / or, the fourth film layer 27 includes a fourth exciton blocking layer 271, a second electron transport layer 272, and a second electron injection layer 273 sequentially stacked on the surface of the substrate 1 along a first direction.

[0125] According to the above embodiments, the first hole injection layer 221 is configured to inject holes from the first electrode layer 21 to the first hole transport layer 222, and the first hole transport layer 222 is configured to transport the holes injected by the first hole injection layer 221 to the first light emitting layer 23. The first exciton blocking layer 223 is configured to block the movement of the electrons in the first light emitting layer 23 towards the first electrode. The first electron injection layer 243 is configured to inject electrons from the second electrode layer 28 to the first electron transport layer 242, and the first electron transport layer 242 is configured to transport the electrons injected by the first electron injection layer 243 to the first light emitting layer 23. The second exciton blocking layer 241 is configured to block the movement of the electrons in the first light emitting layer 23 away from the first electrode. The electrons and the holes recombine in the first light emitting layer 23 to achieve light emission from the first light emitting layer 23.

[0126] The second hole injection layer 251 is configured to inject holes from the first electrode layer 21 to the second hole transport layer 252, and the second hole transport layer 252 is configured to transport the holes injected by the second hole injection layer 251 to the second light emitting layer 26. The third exciton blocking layer 253 is configured to block the movement of the electrons in the second light emitting layer 26 towards the first electrode, which can also be referred to as an electron blocking layer. The second electron injection layer 273 is configured to inject electrons from the second electrode layer 28 to the second electron transport layer 272, and the second electron transport layer 272 is configured to transport the electrons injected by the second electron injection layer 273 to the second light emitting layer 26. The second exciton blocking layer 241 is configured to block the movement of the electrons in the second light emitting layer 26 away from the first electrode. The electrons and the holes recombine in the second light emitting layer 26 to achieve light emission from the second light emitting layer 26.

[0127] In some examples, the main function of the hole injection layer (HIL) is to reduce the hole injection barrier and improve the hole injection efficiency. At least one of the first hole injection layer 221 and the second hole injection layer 251 can be prepared as a single layer film using materials such as HATCN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene), CuPc (copper phthalocyanine), etc. Alternatively, the hole transport material can be prepared by p-type doping, such as NPB (N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine):F4TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), TAPC (1,1-bis[4-[N,N-bis(p-tolyl)amino]phenyl]cyclohexane):MnO3 (manganese anhydride), etc. The thickness of the first hole injection layer 221 and the second hole injection layer 251 can be in the range of 5 nm to 20 nm. When the materials of the first hole injection layer 221 and the second hole injection layer 251 are the same, the doping ratio of the second hole injection layer 251 is higher than that of the first hole injection layer 221.

[0128] The hole transport layer (HTL) is used for transporting holes. At least one of the first hole transport layer 222 and the second hole transport layer 252 can be selected from a carbazole-based material with high hole mobility. The highest occupied molecular orbital (HOMO) energy level of at least one of the first hole transport layer 222 and the second hole transport layer 252 can be in the range of -5.2 eV to -5.6 eV.

[0129] The exciton blocking layer, which can also be referred to as an electron blocking layer (EBL) or a hole blocking layer (HBL), is mainly used for blocking excitons generated in the light-emitting layer from diffusing away from the light-emitting layer, and for transferring holes or electrons. The thickness of at least one of the first exciton blocking layer 223, the second exciton blocking layer 241, the third exciton blocking layer 253, and the fourth exciton blocking layer 271 in the first direction can be in the range of 2 to 15 nm.

[0130] The electron transport layer (ETL) is used for transporting electrons. At least one of the first electron transport layer 242 and the second electron transport layer 272 can be selected from a triazine-based material with high electron mobility. The thickness of at least one of the first electron transport layer 242 and the second electron transport layer 272 in the first direction includes 5 to 50 nm.

[0131] The electron injection layer (EIL) is used for injecting electrons in the second electrode layer 28 into the first light-emitting layer 23 and the second light-emitting layer 26. The thickness of at least one of the first electron injection layer 243 and the second electron injection layer 273 in the first direction includes 0.5 to 20 nm.

[0132] At least one of the first electron injection layer 243, the second electron injection layer 273, the first electron transport layer 242, and the second electron transport layer 272 contains at least one metal element, which can be Li (lithium), Yb (ytterbium), or Ca (calcium).

[0133] It should be noted that the display panel further includes a capping layer (CPL) disposed on the side of the second electrode layer 28 away from the substrate 1, which is used to adjust the refractive index. The capping layer can be selected from an organic small molecule material, and the thickness of the capping layer in the first direction includes 50 to 80 nm. The refractive index of the capping layer under the condition of a wavelength of 460 nm is greater than 1.8.

[0134] It should be noted that for the above-mentioned first hole injection layer 221 and second hole injection layer 251, first hole transport layer 222, second hole transport layer 252, first exciton blocking layer 223, second exciton blocking layer 241, third exciton blocking layer 253, fourth exciton blocking layer 271, first electron transport layer 242, second electron transport layer 272, first electron injection layer 243, second electron injection layer 273 and capping layer, those skilled in the art can change the number of layers, materials and structures of each film layer as needed, not limited to this.

[0135] To further verify the luminous efficiency and lifetime of the display panel provided in the present application, the inventors of the present application provide the following three groups of schemes for comparison, which are respectively the parameters of Example 1, Comparative Example 1 and Example 2. Details are shown in Table 1.

[0136] Table 1: Parameters of Example 1, Comparative Example 1 and Example 2

[0137]

[0138]

[0139] C1, C2, C3 and C4 in Table 1 correspond to the thickness of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction, respectively. λ is the emission wavelength of the first light emitting area 201aE1(d1) of the first light emitting layer 23. E1(d1), E1(d2), E1(d3), E2(d1), E2(d2) and E2(d3) correspond to the thickness of the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a of the first light emitting layer 23 and the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a of the second light emitting layer 26 in the first direction, respectively. S1, S2 and S3 correspond to the ratio of the light emitting area of the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a to the light emitting area of the third light emitting area 203a, respectively.

[0140] In Example 1, Comparative Example 1 and Example 2, the first hole injection layer 221 contains a host material and a doping material, the doping material accounts for 3%, the second hole injection layer 251 contains a host material and a doping material, the doping material accounts for 8%; the first electron injection layer 243 contains a host material and a doping material, the doping ratio is 2%; the second electron transport layer 272 contains a host material and a doping material, the doping ratio is 50%.

[0141] The element properties of the first light-emitting element 201, the second light-emitting element 202, and the third light-emitting element 203 of Examples 1 to 3 were tested, respectively, and the results are shown in Tables 2 to 4 below, and the emission spectra of the first light-emitting element 201, the second light-emitting element 202, and the third light-emitting element 203 are shown in FIGS. 2 to 4, respectively. Figures 4 to 6

[0142] Table 2 Driving voltage, luminous efficiency, and lifetime of the first light-emitting element 201 in Example 1, Comparative Example 1, and Example 2

[0143] First light emitting element 201 Voltage Efficiency Lifetime Example 1 100％ 100％ 100％ Comparative Example 1 99％ 58％ 66％ Example 2 101％ 70％ 110％

[0144] Table 3 Driving voltage, luminous efficiency, and lifetime of the first light-emitting element 201 in Example 1, Comparative Example 1, and Example 2

[0145] Second light emitting element 202 Voltage Efficiency Lifetime Example 1 100％ 100％ 100％ Comparative Example 1 99％ 91％ 83％ Example 2 99％ 97％ 96％

[0146] Table 4 Driving voltage, luminous efficiency, and lifetime of the first light-emitting element 201 in Example 1, Comparative Example 1, and Example 2

[0147] Third light emitting element 203 Voltage Efficiency Lifetime Example 1 100％ 100％ 100％ Comparative Example 1 100％ 77％ 89％ Example 2 100％ 95％ 96％

[0148] Comparing Example 1 and Comparative Example 1, it can be found that the thicknesses of C1 and C3 in the first direction in Comparative Example 1 are different from those in Example 1, the difference in the thicknesses of C1 and C4 in the first direction is larger, and the thicknesses of the other layers are unchanged. The results show that the luminous efficiencies of the first light-emitting element 201, the second light-emitting element 202, and the third light-emitting element 203 in Comparative Example 1 are decreased by 42%, 9%, and 23%, respectively, and the lifetimes are shortened by 34%, 17%, and 11%, respectively, compared with those in Example 1. It can be analyzed that the thickness ratios of the auxiliary film layers and the light-emitting layers in Comparative Example 1 are not matched, which leads to a large difference in the light-emitting efficiencies and the spectra of the two light-emitting layers in the same region, and thus the efficiency is reduced, and the problem of double peaks occurs. As shown in FIG. 5, the EL spectrum of Comparative Example 1 has a more obvious tendency of double peaks or side peaks, which thus leads to serious color deviation under different viewing angles. Moreover, due to the difference in the optical path, the positions of the exciton recombination in the first light-emitting layer 23 and the second light-emitting layer 26 are different, which thus leads to a decrease in the lifetime of the device. Figures 4 to 6

[0149] ​​The first light emitting region 201aE1(d1) of the first light emitting layer 23 in Embodiment 2 is different from that in Embodiment 1. The results show that the light emitting efficiency of the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 in Comparative Example 1 is reduced by 30%, 3% and 5% respectively compared with Embodiment 1, and the service life is prolonged by 10%, shortened by 4% and shortened by 4% respectively. Analysis shows that the overall spectrum does not change because the thicknesses of the auxiliary film layers C1, C2, C3 and C4 are designed as the overall optical path, so the spectrum does not change, and therefore the influence on the second and third light emitting regions 203aE2 and 203aE3 is not great. However, due to the increase in the thicknesses of the first light emitting layer 23 and the second light emitting layer 26 of the first light emitting element 201, i.e. the thickness ratio of the common layer and the light emitting layer is not matched, the light emitted by the first light emitting region 201a of the first light emitting element 201 is at a position where the microcavity interference is weak, and due to the thickening of the first light emitting layer 23 and the second light emitting layer 26, the exciton concentration decreases, which comprehensively leads to a decrease in light emitting efficiency. However, due to the decrease in exciton concentration, the excitation state density decreases, which is beneficial to slowing down the material decay rate, thereby improving the service life.

[0150] In summary, the display panel provided by the present application can optimize the emission spectrum of the light emitting element, improve the light emitting efficiency of the light emitting element and prolong the service life of the light emitting element by optimizing the ratio relationship between the light emitting layer and the auxiliary film layer and between the auxiliary film layers and the light emitting area of each light emitting element.

[0151] Based on the same inventive concept, the present application provides a preparation method of a display panel, comprising:

[0152] S100: providing a substrate 1;

[0153] S200: sequentially forming a first electrode layer 21, a first film layer 22, a first light emitting layer 23, a second film layer 24, a third film layer 25, a second light emitting layer 26, a fourth film layer 27 and a second electrode layer 28 on the substrate 1;

[0154] The display panel comprises at least one first light emitting element 201, at least one second light emitting element 202 and at least one third light emitting element 203 arranged in an array on the surface of the substrate 1 in a second direction, and the second direction is perpendicular to the first direction;

[0155] The first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 each comprise a first light emitting layer 23 and a second light emitting layer 26, and the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 share at least any one or several layers of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27;

[0156] The orthographic projections of the first light emitting element 201, the second light emitting element 202 and the third light emitting element 203 on the substrate 1 board surface correspond to the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a in sequence;

[0157] The maximum value of the thickness of each light emitting area of the first light emitting layer 23 and each light emitting area of the second light emitting layer 26 in the first direction is greater than or equal to the thickness of at least three of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction;

[0158] The minimum value of the thickness of each light emitting area of the first light emitting layer 23 and each light emitting area of the second light emitting layer 26 in the first direction is less than or equal to the thickness of at least three of the first film layer 22, the second film layer 24, the third film layer 25 and the fourth film layer 27 in the first direction, and greater than the absolute value of the difference between the thickness of the first film layer 22 and the fourth film layer 27 in the first direction.

[0159] In some embodiments, sequentially forming the first electrode layer 21, the first film layer 22, the first light emitting layer 23, the second film layer 24, the third film layer 25, the second light emitting layer 26, the fourth film layer 27 and the second electrode layer 28 on the substrate 1 comprises:

[0160] S210: forming the first electrode layer 21 on the substrate 1 by using a photomask;

[0161] S220: forming the first film layer 22 on the first electrode layer 21 by using an open mask;

[0162] S230: sequentially forming the first light emitting layer 23 on the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a of the substrate 1 by using a fine metal mask;

[0163] S240: sequentially forming the second film layer 24 and the third film layer 25 on the first light emitting layer 23 by using an open mask;

[0164] S250: sequentially forming the second light emitting layer 26 on the first light emitting area 201a, the second light emitting area 202a and the third light emitting area 203a of the substrate 1 by using a fine metal mask;

[0165] S260: sequentially forming the fourth film layer 27 and the second electrode layer 28 on the second light emitting layer 26 by using an open mask.

[0166] According to the above-mentioned embodiments, the auxiliary film layers in the embodiments can be prepared by using an open mask, thereby reducing the number of fine metal masks (FMM) used and reducing the material and process costs.

[0167] Based on the same inventive concept, the embodiments of the present application provide a display device. The display device comprises the display panel as described above. Thus, the display device has all the features and advantages of the display panel as described above, which will not be repeated here.

[0168] The above-mentioned embodiments of the present application can be complementary to each other without causing conflicts.

[0169] It is noted that in the drawings, the dimensions of layers and regions can be exaggerated for illustrative clarity. Also, it can be understood that when a element or layer is referred to as being "on" another element or layer, it can be directly on the other element or layer, or intervening layers can also be present. Further, it can be understood that when an element or layer is referred to as being "under" another element or layer, it can be directly under the other element or layer, or one or more intervening layers or elements can also be present. In addition, it can be understood that when a layer or element is referred to as being "between" two layers or elements, it can be the only layer or element between the two layers or elements, or one or more intervening layers or elements can also be present. Like reference numerals can be used to denote like elements throughout the specification and illustrations.

[0170] The terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positions based on the orientations or positions as shown in the drawings, and are used only for the purpose of ease of description and illustration, and do not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

[0171] The terms "first", "second", "third", etc. are used only for descriptive purposes and do not connote or imply any relative importance or any priority of one element over another. Thus, a feature described as "first" can imply or include one or more of the features, explicitly or implicitly. In the description of the application, the meaning of "a", "an" and "the" is intended to be one or more unless otherwise indicated.

[0172] Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the present application cover any and all variations of the application that come within the scope of the claims and their equivalents. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the application indicated by the following claims.

[0173] It is to be understood that the application is not limited to the precise construction already described above and shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application should only be limited by the claims appended hereto.

Claims

1. A display panel, characterized by, The display panel comprises: a substrate; a first electrode layer, a first film layer, a first light-emitting layer, a second film layer, a third film layer, a second light-emitting layer, a fourth film layer and a second electrode layer are sequentially stacked on the substrate in a first direction perpendicular to the substrate and away from the substrate surface; the display panel comprises at least one first light-emitting element, at least one second light-emitting element and at least one third light-emitting element arranged in an array on the substrate surface in a second direction perpendicular to the first direction; the first light-emitting element, the second light-emitting element and the third light-emitting element each comprise the first light-emitting layer and the second light-emitting layer, and at least share any one or more of the first film layer, the second film layer, the third film layer and the fourth film layer; the first light-emitting element, the second light-emitting element and the third light-emitting element correspond to a first light-emitting area, a second light-emitting area and a third light-emitting area in the substrate surface in sequence; the maximum thickness of each light-emitting area of the first light-emitting layer and the second light-emitting layer in the first direction is greater than or equal to the thickness of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction; and / or, the minimum thickness of each light-emitting area of the first light-emitting layer and the second light-emitting layer in the first direction is less than or equal to the thickness of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction, and greater than the absolute value of the difference between the thickness of the first film layer and the fourth film layer in the first direction; the thickness of the third film layer in the first direction is greater than the thickness of the fourth film layer in the first direction, the thickness of the fourth film layer in the first direction is greater than the thickness of the first film layer in the first direction, and the thickness of the first film layer in the first direction is greater than the thickness of the second film layer in the first direction.

2. The display panel of claim 1, wherein, The emission spectrum wavelength of the first light-emitting element is less than that of the second light-emitting element, and the emission spectrum wavelength of the second light-emitting element is less than that of the third light-emitting element.

3. The display panel of claim 2, wherein, Any one of the first film layer, the second film layer, the third film layer, and the fourth film layer has a thickness in the first direction of , satisfies: ； wherein is a non-negative integer, is the emission spectrum wavelength of the first light emitting element.

4. The display panel of claim 2, wherein, The thicknesses of the first film layer, the second film layer, the third film layer, and the fourth film layer in the first direction are respectively , , , , , , , satisfy: ， ； wherein is a non-negative integer, is the emission spectrum wavelength of the third light emitting element.

5. The display panel of claim 4, wherein, The ratio of the thickness of the fourth film layer in the first direction to the thickness of the third film layer in the first direction is greater than or equal to 0.3 and less than or equal to 0.8, and the ratio of the thickness of the second film layer in the first direction to the thickness of the first film layer in the first direction is greater than or equal to 0.3 and less than or equal to 0.

8.

6. The display panel of claim 4, wherein, The absolute value of the difference between the thickness of the fourth film layer and the first film layer in the first direction is less than 10 nm.

7. The display panel of claim 2, wherein, The light-emitting area of the first light-emitting element is greater than that of the second light-emitting element, and the light-emitting area of the second light-emitting element is greater than that of the third light-emitting element.

8. The display panel of claim 7, wherein, The ratio of the luminous area of ​​the second luminous element to the luminous area of ​​the third luminous element is less than 1.6, and the ratio of the luminous area of ​​the first luminous element to the luminous area of ​​the third luminous element is less than 2.

5.

9. The display panel according to claim 1, characterized in that, The absolute value of the difference between the wavelength corresponding to the emission spectrum peak of the first luminescent region of the first luminescent layer and the wavelength corresponding to the emission spectrum peak of the first luminescent region of the second luminescent layer is less than 5 nm. And / or, the absolute value of the difference between the wavelength corresponding to the emission spectral peak of the second luminescent region of the first luminescent layer and the wavelength corresponding to the emission spectral peak of the second luminescent region of the second luminescent layer is less than 5 nm; And / or, the absolute value of the difference between the wavelength corresponding to the emission spectral peak of the third luminescent region of the first luminescent layer and the wavelength corresponding to the emission spectral peak of the third luminescent region of the second luminescent layer is less than 5 nm.

10. The display panel of claim 1, wherein, The first light-emitting layer includes a first auxiliary light-emitting layer and a first main light-emitting layer stacked sequentially along a first direction; the first auxiliary light-emitting layer is at least partially disposed in at least any one of the first light-emitting region, the second light-emitting region, and the third light-emitting region; And / or, the second light-emitting layer includes a second auxiliary light-emitting layer and a second main light-emitting layer stacked sequentially along a first direction; the second auxiliary light-emitting layer is at least partially disposed in at least any one of the first light-emitting region, the second light-emitting region and the third light-emitting region.

11. The display panel according to claim 1, characterized in that, The first film layer includes a first hole injection layer, a first hole transport layer and a first exciton blocking layer sequentially stacked on the surface of the substrate along the first direction; And / or, the second film layer includes a second exciton blocking layer, a first electron transport layer and a first electron injection layer sequentially stacked on the surface of the substrate along the first direction; And / or, the third film layer includes a second hole injection layer, a second hole transport layer and a third exciton blocking layer sequentially stacked on the surface of the substrate along the first direction; And / or, the fourth film layer includes a fourth exciton blocking layer, a second electron transport layer and a second electron injection layer sequentially stacked on the surface of the substrate along the first direction.

12. A method of manufacturing a display panel as claimed in any one of claims 1 to 11, characterized in that include: Provide substrate; A first electrode layer, a first film layer, a first light-emitting layer, a second film layer, a third film layer, a second light-emitting layer, a fourth film layer, and a second electrode layer are sequentially formed on the substrate. The display panel includes at least one first light-emitting element, at least one second light-emitting element, and at least one third light-emitting element arranged in an array on the surface of the substrate along the second direction, wherein the second direction is perpendicular to the first direction; The first light-emitting element, the second light-emitting element, and the third light-emitting element all include the first light-emitting layer and the second light-emitting layer, and the first light-emitting element, the second light-emitting element, and the third light-emitting element share at least one or more of the first film layer, the second film layer, the third film layer, and the fourth film layer; Orthographic projections of the first light emitting element, the second light emitting element and the third light emitting element on the substrate board surface correspond to first light emitting area, second light emitting area and third light emitting area in turn; Maximum values of thickness of each light emitting area of the first light emitting layer and each light emitting area of the second light emitting layer in the first direction are greater than or equal to thicknesses of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction respectively; Minimum values of thickness of each light emitting area of the first light emitting layer and each light emitting area of the second light emitting layer in the first direction are less than or equal to thicknesses of at least three of the first film layer, the second film layer, the third film layer and the fourth film layer in the first direction respectively, and greater than absolute values of differences between the thickness of the first film layer and the thickness of the fourth film layer in the first direction.

13. The method of claim 12, wherein, The sequentially forming the first electrode layer, the first film layer, the first light emitting layer, the second film layer, the third film layer, the second light emitting layer, the fourth film layer and the second electrode layer on the substrate comprises: Forming the first electrode layer on the substrate by using a photomask; Forming the first film layer on the first electrode layer by using an open mask; Forming the first light emitting layer on the first light emitting area, the second light emitting area and the third light emitting area of the substrate in turn by using a fine metal mask; Forming the second film layer and the third film layer on the first light emitting layer in turn by using an open mask; Forming the second light emitting layer on the first light emitting area, the second light emitting area and the third light emitting area of the substrate in turn by using a fine metal mask; Forming the fourth film layer and the second electrode layer on the second light emitting layer in turn by using an open mask.

14. A display device, characterized in that, Comprise: The display panel of any one of claims 1-11. The display panel of any one of claims 1-11.

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