Display panel and display device

Abstract

The invention discloses a display panel and a display device, and the display panel comprises a substrate; the light-emitting functional layer is arranged on one side of the substrate, and the light-emitting functional layer comprises a plurality of light-emitting units; the light extraction layer is arranged on the side, away from the substrate, of the light emitting unit and comprises at least two first-class refraction layers and at least one second-class refraction layer in the direction perpendicular to the plane where the substrate is located, and the first-class refraction layers and the second-class refraction layers are alternately stacked in the direction from the substrate to the light emitting functional layer; the refractive index of each first refractive layer is smaller than that of the second refractive layer, or the refractive index of each first refractive layer is larger than that of the second refractive layer, and the thickness of at least one first refractive layer is different from that of at least one second refractive layer. According to the display panel, spectrum narrowing is achieved, the color point range is expanded, the color gamut is improved, meanwhile, the brightness decay specification is met, the display effect of the display panel is improved, and the use performance of the display panel is improved.

Description

Technical Field

[0001] This invention belongs to the field of electronic product technology, and particularly relates to a display panel and display device. Background Technology

[0002] With the advancement of technology, digital display panels such as those used in smartphones and tablets are widely used, and the display screen is an indispensable human-computer interaction interface in these panels. OLED (Organic Light Emitting Diode) display panels, for example, have advantages such as self-illumination, energy saving, flexibility, and good adaptability. Furthermore, these display panels do not require a backlight and feature fast response times and excellent display effects, attracting user attention and being widely used in smartphones, tablets, and other terminal products.

[0003] However, due to the limitations of existing display panel structural materials, the performance of the display panel cannot meet the requirements.

[0004] Therefore, there is an urgent need for a new display panel and display device. Summary of the Invention

[0005] This invention provides a display panel and display device. By restricting the direction from the substrate to the light-emitting functional layer, a first type of refractive layer and a second type of refractive layer are alternately stacked, and the thickness of the first type of refractive layer and the second type of refractive layer are adjusted to regulate the reflectivity of the light extraction layer, thereby enhancing the gain of the light extraction layer for light emitted in a specific wavelength band, achieving spectral narrowing, expanding the color point range, improving the color gamut, and meeting brightness decay specifications, thereby improving the display effect of the display panel and enhancing the performance of the display panel.

[0006] In a first aspect, embodiments of the present invention provide a display panel, comprising: a substrate; a light-emitting functional layer disposed on one side of the substrate, the light-emitting functional layer including a plurality of light-emitting units; and a light extraction layer disposed on the side of the light-emitting units away from the substrate, along a direction perpendicular to the surface of the substrate, the light extraction layer including at least two first-type refractive layers and at least one second-type refractive layer, in a direction from the substrate to the light-emitting functional layer, the first-type refractive layers and the second-type refractive layers being alternately stacked; the refractive index of each first-type refractive layer being less than the refractive index of the second-type refractive layer, or the refractive index of each first-type refractive layer being greater than the refractive index of the second-type refractive layer, and the thickness of at least one first-type refractive layer and the thickness of at least one second-type refractive layer being different.

[0007] Secondly, embodiments of the present invention provide a display device, including the display panel in any of the above embodiments.

[0008] Compared with related technologies, the display panel provided in this embodiment of the invention includes a substrate, a light-emitting functional layer, and a light extraction layer. The light extraction layer includes a first type of refractive layer and a second type of refractive layer with different refractive indices. By restricting the direction from the substrate to the light-emitting functional layer, the first type of refractive layer and the second type of refractive layer are alternately stacked, and the thickness of the first type of refractive layer and the second type of refractive layer is adjusted to regulate the reflectivity of the light extraction layer, thereby enhancing the gain of the light extraction layer for light emitted in a specific wavelength band, achieving spectral narrowing, expanding the color point range, improving the color gamut, and meeting the brightness decay specifications, thereby improving the display effect of the display panel and enhancing the performance of the display panel. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a display panel according to an embodiment of the present invention; Figure 2 This is provided by one embodiment of the present invention. Figure 1 A partial schematic diagram at point A in the middle; Figure 3 This is provided by one embodiment of the present invention. Figure 2 Schematic diagram of the cross section at point B-B'; Figure 4 This is provided by one embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 5 This is provided by another embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 6 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 7 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 8 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 9 This is provided by another embodiment of the present invention. Figure 3 Schematic diagram of the cross section at point B-B'; Figure 10 This is a schematic diagram of the structure of a display device provided in one embodiment of the present invention.

[0011] Explanation of reference numerals in the attached figures: 100. Substrate; 200, Light-emitting unit; 201, Hole injection layer; 202, Hole transport layer; 203, Electron blocking layer; 204, Light-emitting material layer; 205, Hole blocking layer; 206, Electron transport layer; 207, Electron injection layer; 2011, First hole injection layer; 2021, First hole transport layer; 2031, First electron blocking layer; 2041, First light-emitting material layer; 2051, First hole blocking layer; 2061, First electron transport layer; 2022, Second hole transport layer; 2032, Second electron blocking layer; 2042, Second light-emitting material layer; 2052, Second hole blocking layer; 2062, Second electron transport layer; 2072, Second electron injection layer; 21, First light-emitting unit; 210, First stacked light-emitting unit; 220, Second stacked light-emitting unit; 300. Light extraction layer; 310. Type I refractive layer; 311. Type I sub-refractive layer; 312. Type II sub-refractive layer; 313. Type V sub-refractive layer; 320. Type II refractive layer; 321. Type III sub-refractive layer; 322. Type IV sub-refractive layer; 400. First electrode layer; 500, Second electrode layer; 600, Encapsulation layer; 700, Charge Generation Layer; 800, Light-shielding layer; 810, Light-shielding structure; 820, Opening in the light-shielding layer; 900, color resist structure; G, gate; S, source; D, drain; J, active layer; d1, thickness of the light extraction layer corresponding to the region where the first light-emitting unit is located; d2, thickness of the light extraction layer corresponding to the region where the second light-emitting unit is located. Detailed Implementation

[0012] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention.

[0013] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0014] Among related technologies, OLED (Organic Light Emitting Diode) display panels are widely used in terminal products such as smartphones and tablets due to their fast response speed and excellent display effect. However, in actual production, display panels cannot meet the requirements of high color gamut. Through research and analysis, the inventors of this application have found that the main reason is the limitation of the properties of the light-emitting materials themselves.

[0015] To address the aforementioned issues, the display panel provided in this embodiment of the invention restricts the direction from the substrate 100 to the light-emitting functional layer. A first type of refractive layer 310 and a second type of refractive layer 320 are alternately stacked, and the thicknesses of the first type of refractive layer 310 and the second type of refractive layer 320 are adjusted. This also adjusts the refractive index of the light extraction layer 300, thereby enhancing the gain of the light extraction layer 300 for specific wavelengths of light emitted. This achieves spectral narrowing, expands the color point range, improves the color gamut, and simultaneously meets brightness decay specifications, thereby improving the display effect and performance of the display panel.

[0016] To better understand this invention, the following is combined with... Figures 1 to 10 The display panel and display device according to embodiments of the present invention will be described in detail.

[0017] Please refer to the following: Figures 1 to 4 , Figure 1 This is a schematic diagram of the structure of a display panel according to an embodiment of the present invention; Figure 2 This is provided by one embodiment of the present invention. Figure 1 A partial schematic diagram at point A in the middle; Figure 3 This is provided by one embodiment of the present invention. Figure 3 Schematic diagram of the cross section at point B-B'; Figure 4 This is provided by one embodiment of the present invention. Figure 3 A partial schematic diagram at point C.

[0018] This invention provides a display panel, comprising: a substrate 100; a light-emitting functional layer disposed on one side of the substrate 100, the light-emitting functional layer including a plurality of light-emitting units 200; and a light extraction layer 300 disposed on the side of the light-emitting units 200 away from the substrate 100, along a direction perpendicular to the surface of the substrate 100, the light extraction layer 300 including at least two first-type refractive layers 310 and at least one second-type refractive layer 320, in the direction from the substrate 100 to the light-emitting functional layer, the first-type refractive layers 310 and the second-type refractive layers 320 being alternately stacked; the refractive index of each first-type refractive layer 310 is less than the refractive index of the second-type refractive layer 320, or the refractive index of each first-type refractive layer 310 is greater than the refractive index of the second-type refractive layer 320, and the thickness of at least one first-type refractive layer 310 and the thickness of at least one second-type refractive layer 320 are different.

[0019] The display panel provided in this embodiment of the invention includes a substrate 100, a light-emitting functional layer, and a light extraction layer 300. The light extraction layer 300 includes a first type of refractive layer 310 and a second type of refractive layer 320 with different refractive indices. By restricting the direction from the substrate 100 to the light-emitting functional layer, the first type of refractive layer 310 and the second type of refractive layer 320 are alternately stacked, and the thickness of the first type of refractive layer 310 and the second type of refractive layer 320 is adjusted to regulate the reflectivity of the light extraction layer 300. This enhances the gain of the light extraction layer 300 for light emitted in a specific wavelength band, achieves spectral narrowing, expands the color point range, improves the color gamut, and meets brightness decay specifications, thereby improving the display effect of the display panel and enhancing its performance.

[0020] It should be noted that light undergoes multiple reflections within the microcavity. Light of a specific wavelength satisfies the condition for coherent and constructive interference, thus being enhanced; light of other wavelengths interferes destructively. From the substrate 100 towards the light-emitting functional layer, a first type of refractive layer 310 and a second type of refractive layer 320 are alternately stacked so that the light extraction layer 300 can form a weak microcavity. By adjusting the thickness of each layer of the light extraction layer 300, light of the target wavelength can be made to superimpose in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and increasing the gain for light emitted in a specific wavelength band.

[0021] The luminescent functional layer itself has a broad emission spectrum. When it passes through multiple layers of first-type refractive layer 310 and second-type refractive layer 320 with different refractive indices, some wavelengths are enhanced while others are suppressed, resulting in a narrower half-width at half-maximum (FWHM) of the emitted spectrum. A narrower spectrum means more saturated colors, and the coordinates on the chromaticity diagram are closer to the edge of the spectral locus, thus covering a larger color gamut area.

[0022] Based on requirements, green light device structures with high reflectivity and high monochromatic LC (brightness and vividness) can be prioritized. Then, using a series of first-type refractive layer 310 and second-type refractive layer 320 thickness combinations selected through experiments, and combining the relevant light output parameters of red and blue light device structures, the W color locus, brightness decay, and efficiency are adjusted to select the optimal first-type refractive layer 310 and second-type refractive layer 320 thickness combinations. Optionally, the first-type refractive layer 310 and second-type refractive layer 320 can each consist of multiple layers. The refractive indices of different first-type refractive layers 310 can be the same or different, and their corresponding thicknesses can also be the same or different. Similarly, the refractive indices of different second-type refractive layers 320 can be the same or different, and their corresponding thicknesses can also be the same or different, allowing for targeted adjustments based on actual needs.

[0023] In this embodiment, the substrate 100 can be a rigid substrate, such as a glass substrate; or it can be a flexible substrate, and its material can be polyimide, polystyrene, polyethylene terephthalate, poly(p-xylene), polyethersulfone, or polyethylene naphthalate. The substrate 100 is mainly used to support the devices disposed thereon.

[0024] Please see Figure 3 In some optional embodiments, the display panel further includes a second electrode layer 500 disposed between the light-emitting unit 200 and the light extraction layer 300, and a first electrode layer 400 disposed on the side of the light-emitting unit 200 facing the substrate 100.

[0025] Please see Figure 5 , Figure 5 This is provided by another embodiment of the present invention. Figure 3 A partial schematic diagram at point C; optionally, the light-emitting unit 200 includes one or more of the following: HIL (Hole Inject Layer 201), HTL (Hole Transport Layer 202), electron blocking layer 203, light-emitting material layer 204, hole blocking layer 205, ETL (Electron Transport Layer 206), and EIL (Electron Inject Layer 207). The specific selection can be based on the specific type of the light-emitting layer and is not particularly limited. The electron injection layer 207, electron transport layer 206, and hole blocking layer 205 can be disposed between the second electrode layer 500 and the light-emitting material layer 204. The electron blocking layer 203, hole transport layer 202, and hole injection layer 201 can be disposed between the first electrode layer 400 and the light-emitting material layer 204.

[0026] The material of the first electrode layer 400 is generally a material with a high work function to improve hole injection efficiency. It can be gold (Au), platinum (Pt), titanium (Ti), silver (Ag), indium tin oxide (ITO), zinc tin oxide (IZO), or a transparent conductive polymer (such as polyaniline). For example, the first electrode layer 400 can be made of ITO-Ag-ITO composite material, without any special limitations.

[0027] The material of the second electrode layer 500 can be one of the following metals: silver (Ag), aluminum (Al), lithium (Li), magnesium (Mg), ytterbium (Yb), calcium (Ca), or indium (In). It can also be an alloy of the aforementioned metals, such as magnesium-silver alloy (Mg / Ag) or lithium-aluminum alloy (Li / Al). This embodiment does not limit the material in this regard.

[0028] Optionally, the display panel may also include an encapsulation layer 600 disposed on the side of the light extraction layer 300 facing away from the substrate 100, the encapsulation layer 600 being used to encapsulate and protect the light-emitting functional layer.

[0029] Optionally, the encapsulation layer 600 includes a first encapsulation layer 600, the material of which includes inorganic materials. Specifically, the inorganic materials can be silicon nitride, silicon oxide, and silicon oxynitride, and can be formed using CVD (Chemical Vapor Deposition) process.

[0030] Optionally, the encapsulation layer 600 may further include a second encapsulation layer 600 located on the side of the first encapsulation layer 600 opposite to the substrate 100. The material of the second encapsulation layer 600 may include an organic material. The organic material may be made of resin or polymeric organic material, and may be formed using IJP (Inkjet printing) process.

[0031] Optionally, the encapsulation layer 600 may further include a third encapsulation layer 600 located on the side of the second encapsulation layer 600 away from the substrate 100. The material of the third encapsulation layer 600 includes inorganic materials. Adding an inorganic encapsulation layer 600 outside the organic encapsulation layer 600 can further improve the encapsulation effect of the encapsulation layer 600. In this embodiment, the material of the third encapsulation layer 600 may be the same as or different from the material of the first encapsulation layer 600, and there is no special limitation.

[0032] Optionally, the first encapsulation layer 600 and the third encapsulation layer 600 are made of the same material, so that the first encapsulation layer 600 and the third encapsulation layer 600 can be manufactured using the same equipment, which simplifies the manufacturing process of the display panel.

[0033] Optionally, the display panel further includes an array layer disposed between the substrate 100 and the light-emitting functional layer. The array layer may include driving circuitry. Optionally, the driving circuitry disposed on the array layer includes transistors and storage capacitors. The transistors include an active layer J, a gate G, a source S, and a drain D.

[0034] In some optional embodiments, the refractive index of the first type of refractive layer 310 is less than the refractive index of the second type of refractive layer 320; the refractive index of the first type of refractive layer 310 is greater than or equal to 1.3 and less than or equal to 1.6, and the refractive index of the second type of refractive layer 320 is greater than or equal to 1.8 and less than or equal to 3.

[0035] It is understandable that the refractive index of the first type of refractive layer 310 is less than that of the second type of refractive layer 320. That is, the first type of refractive layer 310 is a low refractive index layer relative to the second type of refractive layer 320, and the second type of refractive layer 320 is a high refractive index layer relative to the first type of refractive layer 310. For example, in the case of a light extraction layer 300 comprising two first type of refractive layers 310 and one second type of refractive layer 320, in the direction from the substrate 100 to the light-emitting functional layer, the first type of refractive layer 310, the second type of refractive layer 320, and the first type of refractive layer 310 are sequentially arranged to form a film structure of low refractive index layer, high refractive index layer, and low refractive index layer, so that the light extraction layer 300 can form a weak microcavity. By adjusting the thickness of each layer of the light extraction layer 300, the light of the target wavelength can be superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and enhancing the gain of light emitted in a specific wavelength band.

[0036] The luminescent functional layer itself has a broad emission spectrum. When it passes through the first type of refractive layer 310, the second type of refractive layer 320, and the first type of refractive layer 310 in sequence, some wavelengths are enhanced while others are suppressed, resulting in a narrower half-width at half-maximum (FWHM) of the emitted spectrum. A narrower spectrum means more saturated colors, and the coordinates on the chromaticity diagram are closer to the edge of the spectral locus, thus covering a larger color gamut area.

[0037] It should be noted that the refractive index of each first-type refractive layer 310 is greater than or equal to 1.3 and less than or equal to 1.6. However, the refractive indices of each first-type refractive layer 310 can be equal or unequal, depending on the actual needs. For example, the refractive index of the first-type refractive layer 310 can be any one of 1.3, 1.4, 1.5, or 1.6. The refractive index of the second-type refractive layer 320 can be any one of 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.

[0038] Optionally, the refractive indices of the first type of refractive layer 310, the second type of refractive layer 320, and the first type of refractive layer 310 stacked in the direction from the substrate 100 to the light-emitting functional layer can be in combination of 1.3, 1.8, 1.4, etc., as long as the above-mentioned refractive index range requirements are met.

[0039] In some alternative embodiments, the material of the first type of refractive layer 310 includes a metal-organic complex material; the material of the second type of refractive layer 320 includes a polycyclic aromatic hydrocarbon derivative organic material.

[0040] It should be noted that in this embodiment, both the first type of refractive layer 310 and the second type of refractive layer 320 can be prepared using organic materials. Compared with the refractive layer being prepared using inorganic materials, organic materials can be prepared using PVD (Physical Vapor Deposition) technology, which is easier to form a film, has high flexibility, is more suitable for flexible electronic devices, and is thinner and lighter.

[0041] Optionally, the material of the first type of refractive layer 310 may include 8-hydroxyquinoline aluminum (Alq3). The material of the second type of refractive layer 320 may include N,N-bis(4-(benzo[d]oxazol-2-yl)phenyl)-7-(pyridin-2-yl)dibenzo[b,d]thiophene-3-amine.

[0042] Please see Figure 4 In some optional embodiments, the light extraction layer 300 includes two first type refractive layers 310 and one second type refractive layer 320; one of the two first type refractive layers 310 is a first sub-refractive layer 311 and the other is a second sub-refractive layer 312, and the second type refractive layer 320 is a third sub-refractive layer 321; the first sub-refractive layer 311, the third sub-refractive layer 321, and the second sub-refractive layer 312 are stacked sequentially in the direction from the substrate 100 to the light-emitting functional layer; along the direction perpendicular to the surface of the substrate 100, the absolute value of the difference between the thickness of the first sub-refractive layer 311 and the thickness of the second sub-refractive layer 312 is less than or equal to 10% of the thickness of the second sub-refractive layer 312.

[0043] It is understood that in this embodiment, the light extraction layer 300 may be composed of three refractive layers. The thickness of the first sub-refractive layer 311 and the thickness of the second sub-refractive layer 312 may both be greater than the thickness of the third sub-refractive layer 321. The difference between the thickness of the first sub-refractive layer 311 and the thickness of the second sub-refractive layer 312 is small. For example, along the direction perpendicular to the surface of the substrate 100, the absolute value of the difference between the thickness of the first sub-refractive layer 311 and the thickness of the second sub-refractive layer 312 may be equal to any one of 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10% of the thickness of the second sub-refractive layer 312.

[0044] In this embodiment, along the direction perpendicular to the plane where the substrate 100 is located, the thickness of the first sub-refractive layer 311 can be equal to the thickness of the second sub-refractive layer 312, that is, the absolute value of the difference between the thickness of the first sub-refractive layer 311 and the thickness of the second sub-refractive layer 312 is equal to 0.

[0045] Through research and experiments, the inventors discovered that the thickness and refractive index relationships of the first sub-refractive layer 311, the third sub-refractive layer 321, and the second sub-refractive layer 312 affect the color coordinates, brightness attenuation, light extraction efficiency, and reflectivity of the light extraction layer 300. By adjusting the thickness of each layer of the light extraction layer 300, the light of the target wavelength can be superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and increasing the gain of light extraction in a specific wavelength band.

[0046] By screening the reflectivity and brightness decay of the formed light extraction layer 300, a combination that satisfies the color gamut and brightness decay is selected. For example, depending on the requirements, a green light device structure with high reflectivity and large monochromatic LC (brightness and vividness) can be prioritized. Then, with the thickness combination of the first sub-refractive layer 311, the third sub-refractive layer 321, and the second sub-refractive layer 312 selected through experiments, and combined with the relevant light output parameters of the red light device structure and the blue light device structure, the W color locus (white locus), brightness decay, and efficiency are adjusted to select the best thickness combination of the first sub-refractive layer 311, the third sub-refractive layer 321, and the second sub-refractive layer 312.

[0047] In some alternative embodiments, the thickness of the first sub-refractive layer 311 and the second sub-refractive layer 312 is greater than or equal to 550 angstroms and less than or equal to 650 angstroms along a direction perpendicular to the plane of the substrate 100.

[0048] Through research and experimentation, the inventors discovered that when the refractive indices of the first sub-refractive layer 311 and the second sub-refractive layer 312 are lower than the refractive index of the third sub-refractive layer 321, the corresponding thicknesses of the first sub-refractive layer 311 and the second sub-refractive layer 312 are greater than the thickness of the third sub-refractive layer 321. This causes the light of the target wavelength to be superimposed in phase at the exit surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and increasing the gain of light emitted in a specific wavelength band.

[0049] For example, along the direction perpendicular to the plane of the substrate 100, the thickness of the first sub-refractive layer 311 and the second sub-refractive layer 312 can be equal, and the refractive index of the first sub-refractive layer 311 and the second sub-refractive layer 312 can be equal to any one of 550 Å, 560 Å, 570 Å, 580 Å, 590 Å, 600 Å, 610 Å, 620 Å, 630 Å, 640 Å, and 650 Å.

[0050] Optionally, the thickness of the third sub-refractive layer 321 can be greater than or equal to 300 angstroms and less than or equal to 400 angstroms.

[0051] For example, the thickness of the third sub-refractive layer 321 can be equal to 300 angstroms, 310 angstroms, 320 angstroms, 330 angstroms, 340 angstroms, 350 angstroms, 360 angstroms, 370 angstroms, 380 angstroms, 390 angstroms, or 400 angstroms.

[0052] Through simulation experiments conducted by the inventors, it was found that in the structure of the light extraction layer 300, in which the first sub-refractive layer 311, the third sub-refractive layer 321, and the second sub-refractive layer 312 are sequentially stacked to form the light extraction layer 300 in the direction from the substrate 100 to the light-emitting functional layer, the thickness of the first sub-refractive layer 311 and the second sub-refractive layer 312 is 600 angstroms, and the thickness of the third sub-refractive layer 321 is 350 angstroms. This allows the wavelength corresponding to green light to be enhanced while the rest is suppressed, thus narrowing the full width at half maximum (FWHM) of the emitted spectrum. A narrower spectrum means more saturated colors, and the coordinates on the chromaticity diagram are closer to the edge of the spectral locus, thereby covering a larger color gamut area and achieving better gain for the green light band, meeting the requirements of color gamut and brightness attenuation.

[0053] In some optional embodiments, the first sub-refractive layer 311 and the second sub-refractive layer 312 are made of the same material. It is understood that since the first sub-refractive layer 311 and the second sub-refractive layer 312 are both first type of refractive layer 310, and their refractive indices are equal or similar, they can be prepared using the same material to facilitate preparation and reduce preparation costs.

[0054] Please see Figures 6 to 7 , Figure 6 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C in the middle; Figure 7 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C; in some optional embodiments, the light extraction layer 300 includes at least two first-type refractive layers 310 and at least two second-type refractive layers 320.

[0055] It is understood that in this embodiment, more first-type refractive layers 310 and second-type refractive layers 320 can be set to achieve more combinations of refractive layer thickness and refractive index, so that the light of the target wavelength is superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement, enhancing the gain of light emitted in a specific band, and increasing the adjustable range of reflectivity, brightness attenuation, color gamut, etc. of the light extraction layer 300.

[0056] Please see Figure 6Optionally, the light extraction layer 300 includes two first-type refractive layers 310 and two second-type refractive layers 320; one of the two first-type refractive layers 310 is a first sub-refractive layer 311 and the other is a second sub-refractive layer 312; one of the two second-type refractive layers 320 is a third sub-refractive layer 321 and the other is a fourth sub-refractive layer 322; the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, and the fourth sub-refractive layer 322 are stacked sequentially in the direction from the substrate 100 to the light-emitting functional layer.

[0057] In this embodiment, the refractive index of the first type of refractive layer 310 is less than that of the second type of refractive layer 320. That is, from the substrate 100 to the light-emitting functional layer, the order of the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, and the fourth sub-refractive layer 322 corresponds to a film structure of low refractive index layer, high refractive index layer, low refractive index layer, and high refractive index layer, so that the light extraction layer 300 can form a weak microcavity. By adjusting the thickness of each layer of the light extraction layer 300, the light of the target wavelength can be superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and enhancing the gain of light emitted in a specific wavelength band.

[0058] Optionally, the thicknesses of the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, and the fourth sub-refractive layer 322 increase sequentially along a direction perpendicular to the plane of the substrate 100.

[0059] Through research and experiments conducted by the inventors, it was discovered that when the light extraction layer 300 includes four sub-refractive layers: a first sub-refractive layer 311, a third sub-refractive layer 321, a second sub-refractive layer 312, and a fourth sub-refractive layer 322, the thickness relationship of the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, and the fourth sub-refractive layer 322 is different from the thickness relationship when the light extraction layer 300 includes three sub-refractive layers. It is necessary to satisfy that the thickness of the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, and the fourth sub-refractive layer 322 increases sequentially along the direction perpendicular to the surface of the substrate 100, so that the light of the target wavelength is superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving a better gain for the green light band, increasing the chromatic coordinate of the green light in the y-direction, and meeting the color gamut requirements.

[0060] Among them, chromaticity coordinates are the coordinates of color. They are also called color representation systems. Commonly used color coordinates use the x-axis (horizontal axis) and y-axis (vertical axis).

[0061] In some alternative embodiments, the thickness of the first sub-refractive layer 311 is greater than or equal to 450 angstroms and less than 550 angstroms along the direction perpendicular to the plane of the substrate 100. For example, the thickness of the first sub-refractive layer 311 can be any of 450 angstroms, 460 angstroms, 470 angstroms, 480 angstroms, 490 angstroms, 500 angstroms, 510 angstroms, 520 angstroms, 530 angstroms, and 540 angstroms.

[0062] Optionally, the thickness of the second sub-refractive layer 312 is greater than or equal to 650 angstroms and less than 750 angstroms. For example, the thickness of the second sub-refractive layer 312 can be any of 650 angstroms, 660 angstroms, 670 angstroms, 680 angstroms, 690 angstroms, 700 angstroms, 710 angstroms, 720 angstroms, 730 angstroms, and 740 angstroms.

[0063] Optionally, the thickness of the third sub-refractive layer 321 is greater than or equal to 550 angstroms and less than 650 angstroms. For example, the thickness of the third sub-refractive layer 321 can be any of 550 angstroms, 560 angstroms, 570 angstroms, 580 angstroms, 590 angstroms, 600 angstroms, 610 angstroms, 620 angstroms, 630 angstroms, and 640 angstroms.

[0064] Optionally, the thickness of the fourth sub-refractive layer 322 is greater than or equal to 750 Å and less than 850 Å. For example, the thickness of the fourth sub-refractive layer 322 can be any of 750 Å, 760 Å, 770 Å, 780 Å, 790 Å, 800 Å, 810 Å, 820 Å, 830 Å, or 840 Å.

[0065] Optionally, through experimental verification by the inventors, when the thickness of the first sub-refractive layer 311 is equal to 500 angstroms, the thickness of the third sub-refractive layer 321 is equal to 600 angstroms, the thickness of the second sub-refractive layer 312 is equal to 700 angstroms, and the thickness of the fourth sub-refractive layer 322 is equal to 800 angstroms, the corresponding color gamut and brightness attenuation of the display panel meet the requirements, and can achieve better gain for the green light band, increase the color coordinate of green light in the y direction, and meet the color gamut requirements.

[0066] In some optional embodiments, the first sub-refractive layer 311 and the second sub-refractive layer 312 are made of the same material, and the third sub-refractive layer 321 and the fourth sub-refractive layer 322 are made of the same material. That is, each first type of refractive layer 310 can be made of the same material, and each second type of refractive layer 320 can be made of the same material, so as to facilitate preparation and reduce preparation cost.

[0067] Please see Figure 7In some optional embodiments, the light extraction layer 300 includes three first-type refractive layers 310 and two second-type refractive layers 320; the three first-type refractive layers 310 include a first sub-refractive layer 311, a second sub-refractive layer 312 and a fifth sub-refractive layer 313, and the two second-type refractive layers 320 include a third sub-refractive layer 321 and a fourth sub-refractive layer 322; the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, the fourth sub-refractive layer 322 and the fifth sub-refractive layer 313 are stacked sequentially in the direction from the substrate 100 to the light-emitting functional layer.

[0068] In this embodiment, the number of sub-refractive layers included in the light extraction layer 300 can be further increased to achieve more combinations of sub-refractive layer thickness and refractive index, thereby increasing the adjustable range of reflectivity, brightness decay, color gamut, etc. of the light extraction layer 300 and achieving optimized display effect of the display panel.

[0069] Optionally, when the refractive index of the first type of refractive layer 310 is less than that of the second type of refractive layer 320, the order of the first sub-refractive layer 311, the third sub-refractive layer 321, the second sub-refractive layer 312, the fourth sub-refractive layer 322, and the fifth sub-refractive layer 313, pointing from the substrate 100 to the light-emitting functional layer, corresponds to a film structure of low refractive index layer, high refractive index layer, low refractive index layer, high refractive index layer, and low refractive index layer. This allows the light extraction layer 300 to form a weak microcavity. By adjusting the thickness of each layer of the light extraction layer 300, the light of the target wavelength can be superimposed in phase at the emission surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement, enhancing the gain of light emission in a specific wavelength band, improving the light emission effect of the display panel, and meeting the color gamut requirements of the display panel image.

[0070] In some alternative embodiments, the thickness of the first sub-refractive layer 311 is greater than or equal to 650 angstroms and less than 750 angstroms along a direction perpendicular to the plane of the substrate 100. For example, the thickness of the first sub-refractive layer 311 may be equal to 650 angstroms and less than 750 angstroms. For example, the thickness of the second sub-refractive layer 312 may be equal to any one of 650 angstroms, 660 angstroms, 670 angstroms, 680 angstroms, 690 angstroms, 700 angstroms, 710 angstroms, 720 angstroms, 730 angstroms, and 740 angstroms.

[0071] Optionally, the thickness of the second sub-refractive layer 312 is greater than or equal to 750 Å and less than or equal to 850 Å. The thickness of the second sub-refractive layer 312 can be any one of 750 Å, 760 Å, 770 Å, 780 Å, 790 Å, 800 Å, 810 Å, 820 Å, 830 Å, and 840 Å.

[0072] Optionally, the thickness of the third sub-refractive layer 321 is greater than or equal to 550 Å and less than or equal to 650 Å. For example, the thickness of the third sub-refractive layer 321 can be greater than or equal to 550 Å and less than 650 Å. For example, the thickness of the third sub-refractive layer 321 can be any of 550 Å, 560 Å, 570 Å, 580 Å, 590 Å, 600 Å, 610 Å, 620 Å, 630 Å, and 640 Å.

[0073] Optionally, the thickness of the fourth sub-refractive layer 322 is greater than or equal to 450 angstroms and less than 550 angstroms. For example, the thickness of the fourth sub-refractive layer 322 can be any of 450 angstroms, 460 angstroms, 470 angstroms, 480 angstroms, 490 angstroms, 500 angstroms, 510 angstroms, 520 angstroms, 530 angstroms, and 540 angstroms.

[0074] Optionally, the thickness of the fifth sub-refractive layer 313 is greater than or equal to 450 Å and less than 550 Å. For example, the thickness of the fifth sub-refractive layer 313 can be any of 450 Å, 460 Å, 470 Å, 480 Å, 490 Å, 500 Å, 510 Å, 520 Å, 530 Å, and 540 Å.

[0075] Optionally, through experimental verification by the inventors, when the light extraction layer 300 includes five layers—a first sub-refractive layer 311, a third sub-refractive layer 321, a second sub-refractive layer 312, a fourth sub-refractive layer 322, and a fifth sub-refractive layer 313—the thickness of the first sub-refractive layer 311 is equal to 700 angstroms, the thickness of the third sub-refractive layer 321 is equal to 600 angstroms, the thickness of the second sub-refractive layer 312 is equal to 800 angstroms, the thickness of the fourth sub-refractive layer 322 is equal to 500 angstroms, and the thickness of the fifth sub-refractive layer 313 is equal to 500 angstroms. This allows light of the target wavelength (e.g., the green light band) to be superimposed in phase at the exit surface (the optical path difference is an integer multiple of the wavelength), thereby achieving interference enhancement and increasing the gain of light emitted in a specific wavelength band. This can achieve a better gain for the green light band, increase the chromatic coordinate of green light in the y-direction, and meet the color gamut requirements.

[0076] In some alternative embodiments, the absolute value of the difference between the thickness of the fourth sub-refractive layer 322 and the thickness of the fifth sub-refractive layer 313 along a direction perpendicular to the plane of the substrate 100 is less than or equal to 10% of the thickness of the fifth sub-refractive layer 313.

[0077] It should be noted that, in this embodiment, although the fourth sub-refractive layer 322 and the fifth sub-refractive layer 313 belong to the first type of refractive layer 310 and the second type of refractive layer 320, respectively, the thicknesses of the fourth sub-refractive layer 322 and the fifth sub-refractive layer 313 can also be set to be equal. That is, along the direction perpendicular to the surface of the substrate 100, the absolute value of the difference between the thickness of the fourth sub-refractive layer 322 and the thickness of the fifth sub-refractive layer 313 is equal to 0% of the thickness of the fifth sub-refractive layer 313. Alternatively, along the direction perpendicular to the surface of the substrate 100, the thicknesses of the fourth sub-refractive layer 322 and the fifth sub-refractive layer 313 can also be set to be similar.

[0078] For example, considering factors such as process errors, the absolute value of the difference between the thickness of the fourth sub-refractive layer 322 and the thickness of the fifth sub-refractive layer 313 along the direction perpendicular to the surface of the substrate 100 can be equal to any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the thickness of the fifth sub-refractive layer 313.

[0079] In some optional embodiments, the first sub-refractive layer 311, the second sub-refractive layer 312, and the fifth sub-refractive layer 313 are made of the same material, and the third sub-refractive layer 321 and the fourth sub-refractive layer 322 are made of the same material. Each first type of refractive layer 310 and each second type of refractive layer 320 can be made of the same material to facilitate fabrication and reduce fabrication costs.

[0080] Please see Figure 3 In some optional embodiments, the light-emitting unit 200 includes a first light-emitting unit 21 and a second light-emitting unit 22 with different light-emitting colors; the absolute value of the difference between the thickness d1 of the light extraction layer corresponding to the region where the first light-emitting unit 21 is located and the thickness d2 of the light extraction layer corresponding to the region where the second light-emitting unit 22 is located is less than or equal to 10% of the thickness d2 of the light extraction layer corresponding to the region where the second light-emitting unit 22 is located.

[0081] It should be noted that in this embodiment, the light extraction layer 300 can be formed as a whole layer with equal thickness throughout, in order to reduce the difficulty of fabrication. That is, the absolute value of the difference between the thickness d1 of the light extraction layer corresponding to the region where the first light-emitting unit 21 is located and the thickness d2 of the light extraction layer corresponding to the region where the second light-emitting unit 22 is located is equal to 0.

[0082] Alternatively, considering factors such as process errors, the absolute value of the difference between the thickness d1 of the light extraction layer in the region where the first light-emitting unit 21 is located and the thickness d2 of the light extraction layer in the region where the second light-emitting unit 22 is located is less than or equal to any one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the thickness d2 of the light extraction layer in the region where the second light-emitting unit 22 is located.

[0083] Optionally, the light-emitting unit 200 may also include a third light-emitting unit 23, the light-emitting color of which is different from the light-emitting colors of the first light-emitting unit 21 and the second light-emitting unit 22.

[0084] Optionally, the first light-emitting unit 21, the second light-emitting unit 22, and the third light-emitting unit 23 can be any one of a red light-emitting unit, a green light-emitting unit, and a blue light-emitting unit, respectively.

[0085] Please see Figure 8 , Figure 8 This is provided by yet another embodiment of the present invention. Figure 3 A partial schematic diagram at point C; in some optional embodiments, along the direction away from the substrate 100, the light-emitting unit 200 includes a first stacked light-emitting unit 210 and a second stacked light-emitting unit 220 arranged sequentially, and a charge generation layer 700 is provided between the first stacked light-emitting unit 210 and the second stacked light-emitting unit 220.

[0086] It should be noted that, in this embodiment, the light-emitting unit 200 can adopt a stacked light-emitting structure, that is, multiple stacked light-emitting units 200 are arranged in series. Optionally, in the direction from the substrate 100 to the light-emitting functional layer, the first stacked light-emitting unit 210 may include a first hole injection layer 2011, a first hole transport layer 2021, a first electron blocking layer 2031, a first light-emitting material layer 2041, a first hole blocking layer 2051, and a first electron transport layer 2061 stacked sequentially. The second stacked light-emitting unit 220 may include a second hole transport layer 2022, a second electron blocking layer 2032, a second light-emitting material layer 2042, a second hole blocking layer 2052, a second electron transport layer 2062, and a second electron injection layer 2072 stacked sequentially. In this embodiment, the first electrode layer 400 can be disposed on the side of the first stacked light-emitting unit 210 facing the substrate 100, and the second electrode layer 500 can be disposed on the side of the second stacked light-emitting unit facing away from the substrate 100. A charge generation layer 700 is provided between the first stacked light-emitting unit 210 and the second stacked light-emitting unit 220. The CGL (Charged Generation Layer 700) is a core functional layer in optoelectronic devices such as stacked OLEDs and QLEDs, composed of P-type and N-type semiconductor materials. Its core function is to generate hole-electron pairs under an applied electric field, achieving efficient carrier injection and thus improving device performance. The main function of the CGL is to generate and separate charges. Holes and electrons are injected into adjacent light-emitting units 200 through an internal electric field, enabling the device to function without relying on the work function of the electrode materials.

[0087] In some optional embodiments, the reflectivity of the light extraction layer 300 is greater than or equal to 50%. The reflectivity of the final light extraction layer 300 can be adjusted by changing the thickness and refractive index of each sub-refractive layer, based on the number of sub-refractive layers included in the light extraction layer 300. The higher the reflectivity of the light extraction layer 300, the higher the light utilization rate of the corresponding light-emitting unit 200, and the greater the brightness of the corresponding display panel. Through research and experiments, the inventors have found that in the prior art, the reflectivity of the light extraction layer 300 for visible light (wavelength range of 390 nm to 700 nm) can only reach 30% to 45%. However, by using the sub-refractive layer film thickness and refractive index combination of the light extraction layer 300 in this application, the reflectivity of the light extraction layer 300 can be increased to 50%, effectively increasing the light extraction efficiency and brightness of the display panel.

[0088] Please see Figure 9 , Figure 9 This is provided by another embodiment of the present invention. Figure 3 A cross-sectional view at point B-B'; In some optional embodiments, the display panel further includes a light-shielding layer 800 and a color resist structure 900 disposed on the side of the light extraction layer 300 facing away from the substrate 100; the light-shielding layer 800 includes a light-shielding structure 810 and a plurality of light-shielding layer openings 820 spaced apart by the light-shielding structure 810, and in a direction perpendicular to the plane of the substrate 100, the color resist structure 900 at least partially overlaps with the light-emitting unit 200, and the color resist structure 900 at least partially overlaps with the light-shielding layer openings 820.

[0089] In this embodiment, the light-shielding structure 810 blocks crosstalk between different colors of emitted light, avoiding problems such as color shift. The color resist structure 900 may include multiple color resists of different colors, corresponding to light-emitting units 200 of different emitted colors, to filter the emitted light of each color respectively. In the direction perpendicular to the plane of the substrate 100, the color resist structure 900 and the light-emitting unit 200 at least partially overlap, that is, the emitted light of the light-emitting unit 200 can enter the color resist structure 900 and exit from the side of the color resist structure 900 away from the light-emitting unit 200. The fact that the color resist structure 900 and the light-shielding layer opening 820 at least partially overlap means that the color resist structure 900 can be entirely located within the light-shielding layer opening 820, partially located within the light-shielding layer opening 820, or not located within the light-shielding layer opening 820 but located on the side of the light-shielding layer opening 820 facing the light-emitting unit 200, etc., can be selected according to actual needs.

[0090] Please see Figure 10 The present invention also provides a display device, including the display panel in any of the above embodiments.

[0091] The display device provided in this embodiment of the invention has the technical effects of the display panel in any of the above embodiments. The explanations of the same or corresponding structures and terms in the above embodiments will not be repeated here.

[0092] The display panel provided in the embodiments of the present invention can be an organic light-emitting diode (OLED) display panel, a quantum dot light-emitting diode (QLED) display panel, or a micro flat panel display panel (Micro-OLED or Micro-LED), etc.

[0093] The display device provided in this embodiment of the invention can be applied to mobile phones or any electronic product with display function, including but not limited to the following categories: televisions, laptops, desktop monitors, tablets, digital cameras, smart bracelets, smart glasses, in-vehicle displays, medical devices, industrial control equipment, touch interactive terminals, etc. This embodiment of the invention does not impose any special limitations on these.

[0094] The above are merely specific embodiments of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

[0095] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

Claims

1. A display panel, characterized in that, include: substrate; A light-emitting functional layer is disposed on one side of the substrate, and the light-emitting functional layer includes a plurality of light-emitting units; A light extraction layer is disposed on the side of the light-emitting unit away from the substrate, along a direction perpendicular to the surface of the substrate. The light extraction layer includes at least two first-type refractive layers and at least one second-type refractive layer, in the direction from the substrate to the light-emitting functional layer. The first-type refractive layers and the second-type refractive layers are alternately stacked. The refractive index of each of the first type of refractive layers is less than the refractive index of the second type of refractive layer, or the refractive index of each of the first type of refractive layers is greater than the refractive index of the second type of refractive layer, and the thickness of at least one of the first type of refractive layers is different from the thickness of at least one of the second type of refractive layers.

2. The display panel according to claim 1, characterized in that, The refractive index of the first type of refractive layer is less than the refractive index of the second type of refractive layer; The refractive index of the first type of refractive layer is greater than or equal to 1.3 and less than or equal to 1.6, and the refractive index of the second type of refractive layer is greater than or equal to 1.8 and less than or equal to 3.

3. The display panel according to claim 2, characterized in that, The materials of the first type of refractive layer include metal-organic complex materials; The materials for the second type of refractive layer include organic materials derived from polycyclic aromatic hydrocarbons.

4. The display panel according to claim 2, characterized in that, The light extraction layer comprises two first-type refractive layers and one second-type refractive layer; Of the two first-type refractive layers, one is a first sub-refractive layer, the other is a second sub-refractive layer, and the third sub-refractive layer is a second-type refractive layer. In the direction from the substrate to the light-emitting functional layer, the first sub-refractive layer, the third sub-refractive layer, and the second sub-refractive layer are stacked sequentially. Along a direction perpendicular to the plane of the substrate, the absolute value of the difference between the thickness of the first sub-refractive layer and the thickness of the second sub-refractive layer is less than or equal to 10% of the thickness of the second sub-refractive layer.

5. The display panel according to claim 4, characterized in that, Along a direction perpendicular to the plane of the substrate, the thicknesses of the first sub-refractive layer and the second sub-refractive layer are greater than or equal to 550 angstroms and less than or equal to 650 angstroms; and / or, The thickness of the third sub-refractive layer is greater than or equal to 300 angstroms and less than or equal to 400 angstroms.

6. The display panel according to claim 4, characterized in that, The first sub-refractive layer and the second sub-refractive layer are made of the same material.

7. The display panel according to claim 1, characterized in that, The light extraction layer comprises at least two first-type refractive layers and at least two second-type refractive layers.

8. The display panel according to claim 7, characterized in that, The light extraction layer comprises two first-type refractive layers and two second-type refractive layers; Of the two first-type refractive layers, one is a first sub-refractive layer and the other is a second sub-refractive layer; of the two second-type refractive layers, one is a third sub-refractive layer and the other is a fourth sub-refractive layer. The first sub-refractive layer, the third sub-refractive layer, the second sub-refractive layer, and the fourth sub-refractive layer are stacked sequentially in the direction from the substrate to the light-emitting functional layer.

9. The display panel according to claim 8, characterized in that, From the substrate toward the light-emitting functional layer, the thicknesses of the first sub-refractive layer, the third sub-refractive layer, the second sub-refractive layer, and the fourth sub-refractive layer increase sequentially.

10. The display panel according to claim 8, characterized in that, Along a direction perpendicular to the plane of the substrate, the thickness of the first sub-refractive layer is greater than or equal to 450 angstroms and less than 550 angstroms; The thickness of the second sub-refractive layer is greater than or equal to 650 angstroms and less than 750 angstroms; The thickness of the third sub-refractive layer is greater than or equal to 550 angstroms and less than 650 angstroms; The thickness of the fourth sub-refractive layer is greater than or equal to 750 angstroms and less than 850 angstroms.

11. The display panel according to claim 8, characterized in that, The first sub-refractive layer and the second sub-refractive layer are made of the same material, and the third sub-refractive layer and the fourth sub-refractive layer are made of the same material.

12. The display panel according to claim 7, characterized in that, The light extraction layer comprises three first-type refractive layers and two second-type refractive layers; The three first-type refractive layers include a first sub-refractive layer, a second sub-refractive layer and a fifth sub-refractive layer; the two second-type refractive layers include a third sub-refractive layer and a fourth sub-refractive layer. From the substrate toward the light-emitting functional layer, the first sub-refractive layer, the third sub-refractive layer, the second sub-refractive layer, the fourth sub-refractive layer, and the fifth sub-refractive layer are stacked sequentially.

13. The display panel according to claim 12, characterized in that, Along a direction perpendicular to the plane of the substrate, the thickness of the first sub-refractive layer is greater than or equal to 650 angstroms and less than 750 angstroms; The thickness of the second sub-refractive layer is greater than or equal to 750 angstroms and less than or equal to 850 angstroms; The thickness of the third sub-refractive layer is greater than or equal to 550 angstroms and less than or equal to 650 angstroms; The thickness of the fourth sub-refractive layer is greater than or equal to 450 angstroms and less than 550 angstroms; The thickness of the fifth sub-refractive layer is greater than or equal to 450 angstroms and less than 550 angstroms.

14. The display panel according to claim 12, characterized in that, Along a direction perpendicular to the plane of the substrate, the absolute value of the difference between the thickness of the fourth sub-refractive layer and the thickness of the fifth sub-refractive layer is less than or equal to 10% of the thickness of the fifth sub-refractive layer.

15. The display panel according to claim 12, characterized in that, The first sub-refractive layer, the second sub-refractive layer, and the fifth sub-refractive layer are made of the same material, and the third sub-refractive layer and the fourth sub-refractive layer are made of the same material.

16. The display panel according to claim 1, characterized in that, The light-emitting unit includes a first light-emitting unit and a second light-emitting unit with different light-emitting colors; The absolute value of the difference between the thickness of the light extraction layer corresponding to the region where the first light-emitting unit is located and the thickness of the light extraction layer corresponding to the region where the second light-emitting unit is located is less than or equal to 10% of the thickness of the light extraction layer corresponding to the region where the second light-emitting unit is located.

17. The display panel according to claim 1, characterized in that, The display panel further includes a second electrode layer disposed between the light-emitting unit and the light extraction layer, and a first electrode layer disposed on the side of the light-emitting unit facing the substrate.

18. The display panel according to claim 17, characterized in that, Along the direction away from the substrate, the light-emitting unit includes a first stacked light-emitting unit and a second stacked light-emitting unit arranged sequentially, with a charge generation layer provided between the first stacked light-emitting unit and the second stacked light-emitting unit.

19. The display panel according to claim 1, characterized in that, The reflectivity of the light extraction layer is greater than or equal to 50%.

20. The display panel according to claim 1, characterized in that, The display panel also includes a light-shielding layer and a color resist structure disposed on the side of the light extraction layer opposite to the substrate; The light-shielding layer includes a light-shielding structure and a plurality of light-shielding layer openings spaced apart by the light-shielding structure. In a direction perpendicular to the plane of the substrate, the color resist structure at least partially overlaps with the light-emitting unit, and the color resist structure at least partially overlaps with the light-shielding layer openings.

21. A display device, characterized in that, Includes the display panel as described in any one of claims 1 to 20.

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