Display panel, method for manufacturing display panel, and display device

Abstract

The application provides a display panel, a preparation method of the display panel and a display device. The display panel comprises a substrate, a light-emitting device layer, a light extraction layer arranged on a side of a second electrode away from the substrate, a light adjusting layer located on a side of the light extraction layer away from the substrate, the light adjusting layer comprising a plurality of medium layers with different refractive indexes, and a cover plate arranged on a side of the light adjusting layer away from the substrate. The refractive indexes of the plurality of medium layers are between the refractive index of the cover plate and the refractive index of the light extraction layer. In the direction away from the substrate, the refractive index gradient of the plurality of medium layers decreases or increases, the difference between the refractive index of the medium layer close to the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the medium layer far from the cover plate and the refractive index of the cover plate, and the difference between the refractive index of the medium layer close to the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the medium layer far from the light extraction layer and the refractive index of the light extraction layer. The technical scheme of the application can reduce rainbow stripes.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a display panel, a method for manufacturing the display panel, and a display device. Background Technology

[0002] Organic light-emitting diode (OLED) and flat panel display devices based on light-emitting diode (LED) technologies are widely used in various consumer electronics products such as mobile phones, televisions, laptops, and desktop computers due to their advantages such as high image quality, energy saving, thin body and wide range of applications, becoming the mainstream of display devices.

[0003] However, current OLED display products have some problems. Summary of the Invention

[0004] In view of the above, embodiments of this application provide a display panel, a method for manufacturing the display panel, and a display device to solve the problems in the prior art.

[0005] This application provides a display panel, comprising: a substrate; a light-emitting device layer disposed on one side of the substrate, the light-emitting device layer including a plurality of light-emitting units, each light-emitting unit including a first electrode, a light-emitting functional layer and a second electrode sequentially stacked along a direction away from the substrate; a light extraction layer disposed on the side of the second electrode away from the substrate; a light conditioning layer located on the side of the light extraction layer away from the substrate, the light conditioning layer including a plurality of dielectric layers with different refractive indices; and a cover plate disposed on the side of the light conditioning layer away from the substrate; wherein the refractive indices of the plurality of dielectric layers are between the refractive index of the cover plate and the refractive index of the light extraction layer, and along the direction away from the substrate, the refractive index gradient of the plurality of dielectric layers decreases or increases, and the difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer away from the cover plate and the refractive index of the cover plate, and the difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer away from the light extraction layer and the refractive index of the light extraction layer.

[0006] In conjunction with the first aspect, the refractive index of the dielectric layer is greater than or equal to 1.5 and less than or equal to 2.5; preferably, the difference between the refractive index of the dielectric layer closest to the cover plate and the refractive index of the cover plate is equal to a first preset value; and / or, the difference between the refractive index of the dielectric layer closest to the light extraction layer and the refractive index of the light extraction layer is equal to a second preset value; preferably, the first preset value is 0; and / or, the second preset value is 0.

[0007] In conjunction with the first aspect, the material of the dielectric layer includes a light-transmitting material; preferably, the extinction coefficient of the light-transmitting material for light in the wavelength range of 440nm to 780nm is equal to a third preset value; preferably, the third preset value is 0; preferably, the material of the dielectric layer includes an inorganic transparent material or an organic transparent material; preferably, the material of the dielectric layer includes at least one of silicon dioxide, silicon nitride, and silicon oxynitride, and / or, the material of the dielectric layer includes polymethyl methacrylate.

[0008] In conjunction with the first aspect, the thickness of the light-adjusting layer is greater than or equal to 5 μm and less than or equal to 8 μm; preferably, the thickness of the dielectric layer is greater than or equal to 110 nm and less than or equal to 195 nm; preferably, the different dielectric layers have the same thickness; preferably, the thickness of the light-extraction layer is greater than or equal to 50 nm and less than or equal to 90 nm; preferably, the display panel further includes a support structure; the support structure is located between the substrate and the cover plate, and the support structure, the substrate, and the cover plate form an accommodating space, in which the light-emitting device layer, the light-extraction layer, and the light-adjusting layer are located; preferably, along the direction away from the substrate, the cross-sectional width of the support structure gradually decreases; preferably, in the direction perpendicular to the substrate, the cross-sectional shape of the support structure includes a trapezoid.

[0009] In conjunction with the first aspect, the display panel further includes a pixel definition layer located between the substrate and the light extraction layer, the pixel definition layer enclosing a plurality of pixel openings, at least a portion of the light-emitting unit being located within the pixel openings; preferably, a first electrode is located between the pixel definition layer and the substrate, a portion of the first electrode is exposed by the pixel opening, at least a portion of the light-emitting functional layer covers the first electrode, and a second electrode covers the light-emitting functional layer.

[0010] A second aspect of this application provides a display panel, comprising: a substrate; a light-emitting device layer disposed on one side of the substrate, the light-emitting device layer including a plurality of light-emitting units, each light-emitting unit including a first electrode, a light-emitting functional layer and a second electrode sequentially stacked along a direction away from the substrate; a light extraction layer disposed on the side of the second electrode away from the substrate; a cover plate located on the side of the light extraction layer away from the substrate; and a support structure located between the substrate and the cover plate, the support structure, the substrate and the cover plate forming an accommodating space, the light-emitting device layer and the light extraction layer being located within the accommodating space; wherein, a light-adjusting layer is provided between the light extraction layer and the cover plate, the light-adjusting layer being an air layer, and the thickness of the light-adjusting layer being greater than or equal to 8 μm and less than or equal to 0.7 mm along a direction perpendicular to the substrate.

[0011] In conjunction with the second aspect, a transparent material layer is provided on the surface of the cover plate facing the substrate, and the refractive index of the transparent material layer is less than the refractive index of the cover plate; preferably, the refractive index of the transparent material layer is greater than or equal to 1.3 and less than or equal to 1.5; preferably, the thickness of the transparent material layer is greater than 0 and less than or equal to 8 μm; preferably, the material of the cover plate includes glass.

[0012] A third aspect of this application provides a method for fabricating a display panel, comprising: fabricating a light-emitting device layer on a substrate, the light-emitting device layer including a plurality of light-emitting units, each light-emitting unit including a first electrode, a light-emitting functional layer, and a second electrode sequentially stacked along a direction away from the substrate; fabricating a light extraction layer on the side of the second electrode away from the substrate; fabricating a light conditioning layer on the side of the light extraction layer away from the substrate, the light conditioning layer including a plurality of dielectric layers with different refractive indices; and disposing a cover plate on the side of the light conditioning layer away from the substrate; wherein the refractive indices of the plurality of dielectric layers are between the refractive index of the cover plate and the refractive index of the light extraction layer, and along the direction away from the substrate, the refractive index gradient of the plurality of dielectric layers decreases or increases, and the difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer away from the cover plate and the refractive index of the cover plate, and the difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer away from the light extraction layer and the refractive index of the light extraction layer.

[0013] In conjunction with the third aspect, after the step of preparing the light-adjusting layer on the side of the light extraction layer away from the substrate, the preparation method further includes: providing a support structure on the periphery of the light-emitting device layer and the light extraction layer, wherein the surface of the support structure away from the substrate protrudes from the surface of the light extraction layer away from the substrate; preferably, preparing the light-adjusting layer on the side of the light extraction layer away from the substrate includes: sequentially preparing multiple dielectric layers on the side of the light extraction layer away from the substrate, wherein the side surfaces of the dielectric layers are in contact with the support structure; preferably, providing a cover plate on the side of the light-adjusting layer away from the substrate includes: placing the cover plate on the side of the light-adjusting layer away from the substrate, wherein the support structure supports the cover plate; preferably, after the step of providing the cover plate on the side of the light-adjusting layer away from the substrate, the preparation method further includes: coating the surface of the support structure away from the light-emitting device layer with an adhesive to seal the display panel.

[0014] The fourth aspect of this application provides a display device, which includes: the display panel described above or a display panel prepared according to any of the above preparation methods.

[0015] The above technical solutions reduce the refractive index difference between the light conditioning layer and the upper and lower interface materials by setting multiple dielectric layers with different refractive indices in the light conditioning layer; or, by increasing the thickness of the air layer, the interference effect generated by light near the light conditioning layer is weakened, thereby reducing the rainbow effect. Attached Figure Description

[0016] Figure 1 This is a schematic cross-sectional view of a display panel provided in an embodiment of this application.

[0017] Figure 2 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application.

[0018] Figure 3This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application.

[0019] Figure 4 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application.

[0020] Figure 5 This is a brightness decay curve of a display panel under different viewing angles in the existing technology;

[0021] Figure 6 This is a brightness decay curve of the display panel under different viewing angles in one embodiment of this application;

[0022] Figure 7 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application.

[0023] Figure 8 This is a brightness decay curve diagram of the display panel under different viewing angles in another embodiment of this application;

[0024] Figure 9 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application.

[0025] Figure 10 This is a schematic flowchart of a method for manufacturing a display panel according to an embodiment of this application.

[0026] Figure 11 This is a schematic diagram of the structure of a display device provided in an embodiment of this application.

[0027] Figure label:

[0028] 10 Substrate; 20 Light-emitting device layer; 210 First electrode; 220 Light-emitting functional layer; 230 Second electrode; 30 Light extraction layer; 40 Light modulation layer; 410 First dielectric layer; 420 Second dielectric layer; 430 Third dielectric layer; 50 Cover plate; 60 Support structure; 201 Pixel opening; 202 Pixel definition layer; 70 Transparent material layer. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] OLED devices typically consist of a substrate, anode, emissive layer, cathode, and cover plate, forming a multi-layered structure. A Fabry-Pérot (FP) microcavity structure (i.e., OLED microcavity) is formed between the anode and cathode, significantly improving the luminous efficiency and color purity of the OLED device. Compared to the OLED microcavity, a microcavity called the Air Gap layer is also formed beneath the cover plate; this is a weak microcavity. When light emitted from the emissive layer propagates within the microcavity, it reflects back and forth between the anode and cathode. Due to the different reflectivities of the anode and cathode for different wavelengths of light, certain wavelengths of light form stable standing waves within the cavity, thus being enhanced, while other wavelengths are attenuated. This results in wavelength-selective enhancement of light. That is, the optical path difference experienced by light in the Air Gap layer and the OLED microcavity varies, causing them to satisfy the conditions for interference enhancement at different locations. As the location changes, the optical path difference also changes continuously, preventing different colors of light from simultaneously satisfying the interference enhancement conditions. This results in a rainbow-like phenomenon of alternating yellow / cyan / violet stripes, severely affecting the uniformity and color accuracy of the image and reducing the user's viewing experience.

[0031] To address the aforementioned technical problems, this application provides a display panel comprising: a substrate; a light-emitting device layer disposed on one side of the substrate, the light-emitting device layer including a plurality of light-emitting units, each light-emitting unit including a first electrode, a light-emitting functional layer, and a second electrode sequentially stacked along a direction away from the substrate; a light extraction layer disposed on the side of the second electrode away from the substrate; a light conditioning layer located on the side of the light extraction layer away from the substrate, the light conditioning layer including a plurality of dielectric layers with different refractive indices; and a cover plate disposed on the side of the light conditioning layer away from the substrate; wherein the refractive indices of the plurality of dielectric layers are between the refractive index of the cover plate and the refractive index of the light extraction layer, and along the direction away from the substrate, the refractive index gradient of the plurality of dielectric layers decreases or increases, and the difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer away from the cover plate and the refractive index of the cover plate, and the difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer away from the light extraction layer and the refractive index of the light extraction layer.

[0032] In this embodiment, by setting multiple dielectric layers with different refractive indices in the light conditioning layer, the refractive index of the light conditioning layer is increased, thereby reducing the refractive index difference between it and the upper and lower layer interfaces, which further weakens the microcavity effect formed by the light conditioning layer and improves the rainbow effect.

[0033] Figure 1 This is a schematic cross-sectional view of a display panel provided in one embodiment of this application. Figure 1 As shown, the display panel includes a substrate 10, a light-emitting device layer 20, a light extraction layer 30, a light adjustment layer 40, and a cover plate 50.

[0034] In the embodiments of this application, the substrate 10 includes a rigid substrate, such as a glass substrate; or, the substrate 10 includes a flexible substrate, such as polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc.

[0035] A light-emitting device layer 20 is disposed on one side of the substrate 10. The light-emitting device layer 20 includes a plurality of light-emitting units. Each light-emitting unit includes a first electrode 210, a light-emitting functional layer 220, and a second electrode 230 sequentially stacked along the direction away from the substrate. In this embodiment, at least a portion of the light-emitting unit is disposed in a pixel opening 201. In this embodiment, the plurality of light-emitting units emit light of different colors, such as red, blue, and green light. In this embodiment, along the direction away from the substrate 10, the light-emitting unit includes a first electrode 210, a light-emitting functional layer 220, and a second electrode 230 sequentially stacked. The first electrode 210 is located between the substrate 10 and the light-emitting functional layer 220. The pixel opening 201 exposes a portion of the first electrode 210. At least a portion of the light-emitting functional layer 220 covers the exposed first electrode 210, and at least a portion of the second electrode 230 covers the light-emitting functional layer 220. In this embodiment, the first electrode 210 is an anode, and the second electrode 230 is a cathode; or, the first electrode 210 is a cathode, and the second electrode 230 is an anode.

[0036] The light extraction layer 30, or CPL (Capping Layer), is disposed on the side of the second electrode 230 away from the substrate 10, which can reduce light loss caused by reflection from the second electrode 230 during light emission.

[0037] The light conditioning layer 40 is located on the side of the light extraction layer 30 facing away from the substrate 10. The light conditioning layer 40 includes multiple dielectric layers with different refractive indices. For example... Figure 1 As shown, the light-adjusting layer 40 includes a first dielectric layer 410, a second dielectric layer 420, and a third dielectric layer 430 with different refractive indices. The number of dielectric layers is not limited in this embodiment.

[0038] Cover plate 50 is disposed on the side of light adjustment layer 40 away from substrate 10. In this embodiment, cover plate 50 can be a film layer made of materials such as glass with high light transmittance, which plays the role of protecting display panel. In this embodiment, cover plate 50 can be made of rigid material, which has a relatively low cost.

[0039] The refractive indices of the multiple dielectric layers are between those of the cover plate 50 and the light extraction layer 30. Along the direction away from the substrate 10, the refractive index gradient of the multiple dielectric layers decreases or increases. The difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate 50 is smaller than the difference between the refractive index of the dielectric layer far from the cover plate 50 and the refractive index of the cover plate 50. The difference between the refractive index of the dielectric layer near the light extraction layer 30 and the refractive index of the light extraction layer 30 is smaller than the difference between the refractive index of the dielectric layer far from the light extraction layer 30 and the refractive index of the light extraction layer 30.

[0040] It is understandable that when different materials are used to fabricate the light extraction layer 30 and the cover plate 50, the refractive index of the light extraction layer 30 and the cover plate 50 may not be fixed. Therefore, in order to reduce the refractive index difference between the light conditioning layer 40 and its upper and lower interfaces, the refractive indices of the multiple dielectric layers of the light conditioning layer 40 can be set between the refractive index of the cover plate 50 and the refractive index of the light extraction layer 30. Specifically, when the refractive index of the material used in the light extraction layer 30 is greater than that of the cover plate 50, the refractive index gradient of the multiple dielectric layers can be reduced along the direction away from the substrate 10; when the refractive index of the material used in the light extraction layer 30 is less than that of the cover plate 50, the refractive index gradient of the multiple dielectric layers can be increased along the direction away from the substrate 10. This avoids a large refractive index difference between the light extraction layer 30 and the dielectric layers of the adjacent light conditioning layer 40, thus improving the display effect of the display panel.

[0041] Optionally, the cover plate 50 can be made of glass with a refractive index of 1.5, considering that the refractive index of the light extraction layer 30 is greater than or equal to 1.3 and less than or equal to 2.5. Therefore, the refractive index of the dielectric layer is greater than or equal to 1.3 and less than or equal to 2.5. If the refractive index of the material used in the light extraction layer 30 is greater than 1.5, a dielectric layer with a higher refractive index can be positioned closer to the light extraction layer 30, and a dielectric layer with a lower refractive index can be positioned closer to the cover plate 50, so that the refractive index gradient of the multiple dielectric layers decreases along the direction away from the substrate 10; if the refractive index of the material used in the light extraction layer 30 is less than 1.5, a dielectric layer with a lower refractive index can be positioned closer to the light extraction layer 30, and a dielectric layer with a higher refractive index can be positioned closer to the cover plate 50, so that the refractive index gradient of the multiple dielectric layers increases along the direction away from the substrate 10.

[0042] Considering that the refractive index of most light extraction layer 30 materials is greater than or equal to 1.5, in this embodiment of the application, the refractive index of the dielectric layer is greater than or equal to 1.5 and less than or equal to 2.5.

[0043] To further reduce the refractive index difference between the light conditioning layer 40 and its upper and lower interfaces, the degree of difference between the refractive index of the dielectric layer closest to the cover plate 50 and the refractive index of the cover plate 50 can be reduced, and / or, the degree of difference between the refractive index of the dielectric layer closest to the light extraction layer 30 and the refractive index of the light extraction layer 30 can be reduced. The degree of difference can be determined based on absolute difference and / or relative difference.

[0044] In this embodiment, the degree of difference is determined based on the absolute difference. Specifically, the difference between the refractive index of the dielectric layer closest to the cover plate 50 and the refractive index of the cover plate 50 is set to be equal to a first preset value, and / or the difference between the refractive index of the dielectric layer closest to the light extraction layer 30 and the refractive index of the light extraction layer 30 is set to be equal to a second preset value. The first and second preset values ​​can be the same or different. The first preset value can be 0, 0.1, 0.01, 0.001, or 0.001. The second preset value can also be 0, 0.1, 0.01, 0.001, or 0.001. Preferably, the first preset value is 0; and / or, the second preset value is 0. The advantage of this is that by controlling the refractive index of the light adjustment layer 40 and the dielectric layer closest to its upper and lower interfaces, the effect of reducing the refractive index difference between the light adjustment layer 40 and its upper and lower interfaces can be reduced, further reducing rainbow patterns.

[0045] In order to reduce the difference in refractive index without reducing the display brightness, a light-transmitting material can be selected as the medium layer material to improve light transmittance and further improve display brightness.

[0046] Optionally, the light transmittance of the dielectric layer material can be determined based on its transmittance and / or extinction coefficient. For example, a material with high transmittance and / or low extinction coefficient can be selected as the dielectric layer material. In this embodiment, the light transmittance of the dielectric layer material is determined based on the extinction coefficient, and a material with a smaller extinction coefficient is selected as the dielectric layer material.

[0047] Furthermore, considering the limited wavelength range of the light-emitting unit, in order to further improve the light transmittance, a material with better light transmittance within the wavelength range of the light-emitting unit can be selected.

[0048] In this embodiment, multiple light-emitting units emit light of various colors. For example, the light-emitting units include red, blue, and green light-emitting units. Therefore, the wavelength range of the light-emitting units is 440nm to 780nm. Thus, the light-transmitting material can be selected based on the extinction coefficient of light within the 440nm to 780nm wavelength range. Specifically, the extinction coefficient of the light-transmitting material for light within the 440nm to 780nm wavelength range can be set to equal a third preset value; the third value can be 0.1, 0.01, or 0.001. Preferably, the third preset value is 0. It should be noted that when measuring the extinction coefficient, due to the influence of impurities or structural defects within the material, a small amount of light absorption or scattering may occur, resulting in the actual measured extinction coefficient being slightly greater than 0.

[0049] Preferably, the material of the dielectric layer includes an inorganic transparent material or an organic transparent material; the material of the dielectric layer includes at least one of silicon dioxide, silicon nitride, and silicon oxynitride, and / or the material of the dielectric layer includes at least one of polymethyl methacrylate, polycarbonate, polystyrene, polyethylene terephthalate, and polyvinyl alcohol, preferably, the material of the dielectric layer includes polymethyl methacrylate.

[0050] In this embodiment, the dielectric layer material includes silicon nitride, which not only reduces the refractive index difference but also provides a certain degree of encapsulation and protection.

[0051] In this embodiment, by setting the refractive index of the multilayer medium to gradually decrease from the light extraction layer 30 (high refractive index) to the cover plate 50 (low refractive index), a refractive index gradient is formed. This decomposes the originally single abrupt interface into multiple gradual interfaces, enabling the light incident on the light conditioning layer 40 to gradually propagate to the outside, avoiding color shift or viewing angle dependence caused by microcavity resonance. However, if the thickness of the light conditioning layer 40 is too thin, a sufficient number of refractive index gradient layers cannot be achieved, resulting in limited optical gain; if the thickness of the light conditioning layer 40 is too thick, it will increase the overall thickness of the screen and raise material costs. Therefore, to balance optical performance and process cost, preferably, the thickness of the light conditioning layer 40 is greater than or equal to 5 μm and less than or equal to 8 μm. For example, the thickness of the light conditioning layer 40 can be 5 μm, 5.5 μm, 5.8 μm, 6 μm, 6.5 μm, 7.5 μm, or 8 μm, etc. This not only improves light extraction efficiency but also interferes with the original interference effect.

[0052] Considering that the relationship between optical path difference and wavelength is very important in optical phenomena such as interference, in the embodiments of this application, the optical path is equal to the refractive index of the material multiplied by the thickness of the material through which light propagates. Under the same geometric path, the greater the refractive index, the longer the optical path. When the optical path difference between two beams is an integer multiple of the wavelength, bright fringes appear; when the optical path difference is an odd multiple of half the wavelength, dark fringes appear.

[0053] In this embodiment, for cases where multiple light-emitting units have different wavelengths, in addition to adjusting the refractive index of the dielectric layer, the thickness of the dielectric layer can also be adjusted to enhance or weaken the interference of light of a specific wavelength, thereby reducing the rainbow effect.

[0054] In some scenarios, when light is incident perpendicularly on a material with a thickness of one-quarter wavelength, the optical path difference between the two beams reflected from the upper and lower surfaces of the material is exactly half a wavelength. According to the principle of light interference, these two reflected beams will undergo destructive interference, thereby weakening the intensity of the reflected light or even approaching zero. Therefore, the thickness of the dielectric layer can be set to one-quarter wavelength to reduce the interference effect and improve the rainbow effect. In the embodiments of this application, the wavelength range of the light-emitting unit is 440nm to 780nm. Preferably, the thickness of the dielectric layer is greater than or equal to 110nm and less than or equal to 195nm. For example, the thickness of the dielectric layer can be 110nm, 120nm, 125nm, 140nm, 180nm, 190nm, or 195nm, etc.

[0055] It should be noted that there is no specific limitation on the thickness between different dielectric layers, as long as the refractive index of multiple dielectric layers increases or decreases.

[0056] Preferably, different dielectric layers can be set to have the same thickness.

[0057] It is understandable that if the light extraction layer 30 is too thin, it may not be able to sufficiently couple the light generated internally to the outside, resulting in some light being absorbed or scattered and lost inside the device. If the light extraction layer 30 is too thick, it may increase the loss of light propagation within the layer, similarly reducing the light extraction efficiency. Furthermore, uneven thickness may lead to different extraction efficiencies in different regions, resulting in uneven output light intensity distribution. Therefore, a suitable and uniform thickness allows for more uniform light extraction, improving the uniformity of light intensity distribution. In this embodiment, considering the different propagation characteristics of light of different wavelengths in materials, for the light generated by common optoelectronic devices, the thickness of the light extraction layer 30 is greater than or equal to 50 nm and less than or equal to 90 nm, depending on the refractive index range of the material. For example, the thickness of the light extraction layer 30 can be 50 nm, 55.5 nm, 60.5 nm, 68 nm, 70 nm, 75 nm, 80 nm, or 90 nm, etc. This can better match the wavelength range and optical characteristics, and will not cause a decrease in optical performance due to excessively large or small thickness.

[0058] refer to Figures 2-4The display panel also includes a support structure 60. In this embodiment, the support structure 60 can be made of materials with good water and oxygen barrier properties, such as inorganic materials, to provide support for the cover plate 50 while also acting as a water and oxygen barrier. Specifically, the support structure 60 can be a photoresist material, glass powder adhesive, glass interlayer film, or organic polymer material, etc.

[0059] Reference 2- Figure 4 The support structure 60 is located between the substrate 10 and the cover plate 50. The support structure 60, the substrate 10 and the cover plate 50 form a receiving space. The light-emitting device layer 20, the light extraction layer 30 and the light adjustment layer 40 are located within the receiving space.

[0060] Specifically, considering that the cover plate 50 is usually made of rigid material and has high requirements for support, this embodiment provides a support structure 60 between the substrate 10 and the cover plate 50 to support the cover plate 50. The support structure 60, the substrate 10, and the cover plate 50 form a receiving cavity. During the preparation, the substrate 10, the light-emitting device layer 20 and the support structure 60 need to be prepared first to form the spatial region of the light-adjusting layer 40. Then, the dielectric layer material is filled in the spatial region of the light-adjusting layer 40 to avoid the receiving cavity from being filled with air and forming gaps.

[0061] Understandably, if the projected area of ​​the support structure 60 on the substrate 10 is too large, it will block some of the light emitted by the light-emitting unit, thus affecting the light extraction efficiency. Therefore, in order to improve the light extraction efficiency, the cross-sectional width of the support structure 60 can be gradually reduced along the direction away from the substrate 10 to achieve a smaller projected area, reduce the obstruction of emitted light, and allow more light to be emitted smoothly from the device, thereby further improving the luminous efficiency and brightness of the device.

[0062] refer to Figure 2 and Figure 3 In the direction perpendicular to the substrate 10, the cross-sectional shape of the support structure 60 may also include a trapezoidal shape. Figure 2 ) or arc ( Figure 3 However, it is necessary to ensure that the cross-sectional width of the support structure 60 gradually decreases along the direction away from the substrate 10.

[0063] In this embodiment, the cross-sectional shape of the support structure 60 in the direction perpendicular to the substrate 10 includes a trapezoid. The advantage of doing so is that it can not only improve the luminous efficiency, but also make the external force acting on the support structure 60 more evenly distributed, reduce stress concentration, and better withstand and disperse these forces when subjected to external forces (such as mechanical vibration, thermal stress, etc.), reduce the risk of structural damage, and improve the mechanical stability and reliability of the device.

[0064] Figure 4This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application. For example... Figure 4 As shown, the display panel also includes a pixel definition layer (PDL) 202, which is located between the substrate 10 and the light extraction layer 30. The pixel definition layer 202 encloses a plurality of pixel openings 201, and at least a portion of the light-emitting unit is located within the pixel opening 201. Preferably, the first electrode 210 is located between the pixel definition layer 202 and the substrate 10, the pixel opening 201 exposes a portion of the first electrode 210, at least a portion of the light-emitting functional layer 220 covers the first electrode 210, and the second electrode 230 covers the light-emitting functional layer 220.

[0065] The pixel definition layer 202 is located between the substrate 10 and the light extraction layer 30. It is used to enclose multiple pixel openings 201 to define the area of ​​a pixel. These pixel openings 201 emit light by confining the light-emitting units within the pixel area defined by the pixel definition layer 202, thereby ensuring that each pixel can independently emit light of different colors and brightness, and finally combine to form a complete image.

[0066] In this embodiment, the first electrode 210 is the anode, and the second electrode 230 is the cathode. Specifically, the first electrode 210, as the anode, is located directly above the substrate 10 and is covered by the pixel definition layer 202. The pixel opening 201 exposes a portion of the first electrode 210. To enable the first electrode 210 to make electrical connections with other functional layers, and to allow the portion exposed through the pixel opening 201 to contact the light-emitting device layer 20, providing a channel for charge injection into the light-emitting device layer 20, thereby exciting the light-emitting device layer 20 to emit light.

[0067] By positioning the pixel definition layer 202 between the substrate 10 and the light extraction layer 30, it covers the non-light-emitting area of ​​the first electrode 210 (anode). The light-emitting functional layer 220 covers the exposed anode area and extends to the edge of the opening of the pixel definition layer 202. When charge is injected into the first electrode 210, these charges recombine with other charge carriers in the light-emitting functional layer 220, thereby achieving light emission.

[0068] The design of the light-emitting functional layer 220 covering the first electrode 210 helps to improve charge injection efficiency and light emission efficiency, ensuring that the light emission process can be carried out stably and efficiently. The second electrode 230 covers the entire light-emitting functional layer 220, forming a top electrode, which is used to form an electric field with the first electrode 210 to drive the charge to move in the light-emitting functional layer 220, and also plays the role of collecting charge, so that the entire circuit forms a closed loop, ensuring that the display panel can work normally.

[0069] The light extraction layer 30 is located above the cathode. By using microlenses, refractive index matching, or scattering structures, the transmittance of light from the inside of the device to the outside is improved, and the total internal reflection loss is reduced.

[0070] In this embodiment, pixel-level light emission control of the display panel is achieved through the coordinated operation of the pixel definition layer 202, electrodes, and light-emitting functional layer 220, thereby enabling the display of high-quality images.

[0071] A pixel definition layer 202 is located on one side of the substrate 10, and the pixel definition layer 202 surrounds and forms a plurality of pixel openings 201. In the embodiments of this application, the pixel definition layer 202 includes organic or inorganic materials, and this application does not impose any limitations. For ease of explanation, only three pixel openings are shown in the figures. It can be understood that the display panel of this application includes a plurality of pixel openings 201.

[0072] contrast Figure 5 and Figure 6 ,in, Figure 5 and Figure 6 The horizontal axis represents different viewing angles relative to the display panel, and the vertical axis represents brightness. It can be seen that compared with the display panels in the prior art, the brightness decay (i.e. brightness decay) of the display panel in this application embodiment is significantly smoother, reflecting that the rainbow effect is weakened or disappears.

[0073] Figure 7 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application. Figure 7 The display panel shown is Figure 1 The difference in the display panel shown is that the light adjustment layer 40 is an air layer. By increasing the thickness of the air layer, the coherence of the light inside the light adjustment layer 40 is weakened, so as to weaken or even eliminate the interference effect and further reduce the rainbow pattern.

[0074] like Figure 7 As shown, the display panel includes: a substrate 10; a light-emitting device layer 20; a light extraction layer 30; a cover plate 50; and a support structure 60. The light-emitting device layer 20 is disposed on one side of the substrate 10 and includes multiple light-emitting units. Each light-emitting unit includes a first electrode 210, a light-emitting functional layer 220, and a second electrode 230, which are sequentially stacked along a direction away from the substrate. The light extraction layer 30 is disposed on the side of the second electrode 230 facing away from the substrate 10. The cover plate 50 is located on the side of the light extraction layer 30 facing away from the substrate 10. The support structure 60 is located between the substrate 10 and the cover plate 50. The support structure 60, the substrate 10, and the cover plate 50 form an accommodating space, within which the light-emitting device layer 20 and the light extraction layer 30 are located.

[0075] The light extraction layer 30 and the cover plate 40 are respectively provided with a light conditioning layer 40. The light conditioning layer 40 is an air layer, and its thickness is greater than or equal to 8 μm and less than or equal to 0.7 mm along the direction perpendicular to the substrate 40. The thicker air layer can increase the multiple reflection paths of light in the light conditioning layer 40, disperse the microcavity resonance energy, and reduce the rainbow effect caused by the microcavity effect.

[0076] contrast Figure 5 and Figure 8 ,in, Figure 5 and Figure 8 The horizontal axis represents different viewing angles relative to the display panel, and the vertical axis represents brightness. It can be seen that compared with the display panels in the prior art, the brightness attenuation of the display panel in this application embodiment is significantly smoother, which can reflect the reduction or disappearance of the rainbow effect.

[0077] Figure 9 This is a cross-sectional structural diagram of a display panel provided in another embodiment of this application. For example... Figure 9 As shown, in order to further reduce the interference effect of the light adjustment layer 40, the refractive index difference at the interface between the light adjustment layer 40 and the cover plate 50 can be reduced. Therefore, in this embodiment, a transparent material layer 70 is added between the air layer and the cover plate 50. The refractive index of the transparent material layer 70 is less than that of the cover plate. It can be understood that the transparent material layer 70 is disposed near the cover plate. In order to reduce the refractive index difference at the interface between the light adjustment layer 40 and the cover plate 50, the refractive index of the transparent material should be close to that of the cover plate 50.

[0078] Optionally, the cover plate 50 is made of glass with a refractive index of approximately 1.5, the air layer has a refractive index of approximately 1, and the transparent material has a refractive index greater than or equal to 1 and less than or equal to 1.5. Preferably, the transparent material has a refractive index close to 1.5. In this embodiment, the refractive index of the transparent material layer 70 is greater than or equal to 1.3 and less than or equal to 1.5. By controlling the refractive index of the transparent material layer 70 to be greater than or equal to 1.3 and less than or equal to 1.5, the refractive index difference between the air layer and the cover plate 50 can be reduced, reducing total internal reflection at the interface and improving light extraction efficiency.

[0079] Considering that the required thickness of the transparent material layer 70 may vary depending on the application scenario, specifically for rigid OLED screens, the thickness of the transparent material layer 70 is typically between tens of nanometers and tens of micrometers. For example, for screens that prioritize optical performance optimization, a transparent material layer 70 thickness of less than 5 μm might be chosen; while if thinness and cost control are prioritized, the thickness might be around tens of nanometers to 1 μm. Therefore, the thickness of the transparent material layer 70 can be optimized and determined based on the specific application scenario, product positioning, and actual manufacturing process of the rigid OLED screen.

[0080] In this embodiment of the application, in order to further reduce the refractive index difference between the air layer and the cover plate 50, the thickness of the transparent material layer 70 can be set to be greater than 0 and less than or equal to 8 μm. Specifically, the thickness can be greater than or equal to 1 μm and less than or equal to 8 μm, such as 1 μm, 3 μm, 5 μm, or 8 μm; it can also be between tens of nanometers and hundreds of nanometers, such as 50 nm, 100 nm, or 200 nm.

[0081] Optionally, the transparent material layer 70 may be a fluorine-containing material. In this embodiment, a layer of fluorine-containing material may be spin-coated onto the surface of the cover plate 50 facing the substrate 10. The advantage of doing so is that spin-coating the transparent material can better control the refraction and scattering of light without affecting the light transmittance of the cover plate 50, and also helps to optimize the optical performance of the display panel, improve the brightness uniformity and contrast of the screen, and make the displayed image clearer and more vivid.

[0082] Figure 10 This is a schematic flowchart illustrating a method for manufacturing a display panel according to an embodiment of this application. Figure 10 As shown, the method for manufacturing this display panel includes the following steps.

[0083] S801, a light-emitting device layer is fabricated on a substrate. The light-emitting device layer includes multiple light-emitting units. Each light-emitting unit includes a first electrode, a light-emitting functional layer, and a second electrode that are sequentially stacked along a direction away from the substrate.

[0084] S802, a light extraction layer is prepared on the side of the second electrode away from the substrate.

[0085] S803, an optical conditioning layer is prepared on the side of the optical extraction layer away from the substrate. The optical conditioning layer includes multiple dielectric layers with different refractive indices.

[0086] S804, a cover plate is provided on the side of the light conditioning layer away from the substrate.

[0087] Among them, the refractive indices of multiple dielectric layers are between the refractive index of the cover plate and the refractive index of the light extraction layer. Along the direction away from the substrate, the refractive index gradient of multiple dielectric layers decreases or increases. The difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer far from the cover plate and the refractive index of the cover plate. The difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer far from the light extraction layer and the refractive index of the light extraction layer.

[0088] Specifically, a suitable substrate material, such as glass or plastic, is selected and cleaned to remove surface dust, oil, and other impurities. For example, ultrasonic cleaning with organic solvents such as acetone or ethanol can be used, followed by rinsing with deionized water and drying with nitrogen or in an oven. Then, the substrate undergoes surface treatment to improve adhesion and contact performance between the substrate and the anode. For instance, plasma treatment or ultraviolet ozone treatment can be used to generate active groups such as hydroxyl groups on the substrate surface.

[0089] Furthermore, a first electrode (e.g., anode), a light-emitting functional layer, and a second electrode (cathode) are sequentially fabricated on the substrate, and a light extraction layer is fabricated on the side of the second electrode facing away from the substrate. After the light extraction layer is fabricated, multiple dielectric layers with different refractive indices are fabricated on the side of the light extraction layer facing away from the substrate along the direction facing away from the substrate, such that the refractive index gradient of the multiple dielectric layers decreases or increases, and the difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer far from the cover plate and the refractive index of the cover plate, and the difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer far from the light extraction layer and the refractive index of the light extraction layer.

[0090] Finally, a cover plate is placed on the side of the light-modulating layer facing away from the substrate. This cover plate can be made of encapsulation materials such as glass or metal, and is sealed to the substrate using sealant or welding. This creates a containment space within the support structure, substrate, and cover plate, where the light-emitting device layer, light extraction layer, and light-modulating layer are located. During the encapsulation process, it is crucial to ensure good adhesion between the encapsulation material and the light-emitting device layer, and that the encapsulated device exhibits good hermeticity and stability.

[0091] It should be noted that the substrate, first electrode, light-emitting functional layer, second electrode, and light extraction layer can be prepared using existing methods, and the embodiments of this application do not impose specific limitations on this.

[0092] In this embodiment of the application, after the step of preparing a light conditioning layer on the side of the light extraction layer away from the substrate, the preparation method further includes: providing a support structure on the periphery of the light-emitting device layer and the light extraction layer, wherein the surface of the support structure away from the substrate protrudes from the surface of the light extraction layer away from the substrate.

[0093] Specifically, after the light conditioning layer is fabricated, a support structure is set around the light-emitting device layer and the light extraction layer. The surface of the support structure facing away from the substrate protrudes from the surface of the light extraction layer facing away from the substrate, so that the support structure and the light extraction layer form a semi-enclosed space (i.e., the light conditioning layer).

[0094] Preferably, a light conditioning layer is prepared on the side of the light extraction layer away from the substrate, comprising: sequentially preparing multiple dielectric layers on the side of the light extraction layer away from the substrate, wherein the sides of the dielectric layers are in contact with the support structure. In the embodiments of this application, within the aforementioned semi-enclosed space, multiple dielectric layers with different refractive indices are sequentially filled on the side of the light extraction layer away from the substrate, such that the refractive index gradient of the multiple dielectric layers decreases or increases, and the sides of each dielectric layer are in contact with the support structure, thereby ensuring that each dielectric layer is uniformly distributed.

[0095] Furthermore, a cover plate is placed on the side of the light conditioning layer away from the substrate, and a support structure supports the cover plate, so that the support structure, the substrate and the cover plate form an accommodating space, in which the light-emitting device layer, the light extraction layer and the light conditioning layer are located.

[0096] In this embodiment of the application, after the step of setting a cover plate on the side of the light adjustment layer away from the substrate, the preparation method further includes: coating an adhesive on the surface of the support structure away from the light-emitting device layer to seal the display panel.

[0097] Specifically, for the side of the support structure that does not contact the light-emitting device layer, an adhesive can be coated on the surface and combined with other encapsulation layers (such as cover plates) to form a sealed interface. This allows the adhesive and the support structure to form a physical barrier, extending the lifespan of the display panel.

[0098] Figure 11 This is a schematic diagram of a display device according to an embodiment of this application. The display device includes any of the above-described display panels or a display panel prepared using any of the above-described manufacturing methods. Figure 11 As shown, display device 900 is a product with image display function. For example, display device 900 can be used to display static images, such as pictures or photographs. Display device 900 can also be used to display moving images, such as videos.

[0099] Display device 900 can be a laptop, mobile phone, handheld or portable computer, camera, camcorder, in-vehicle smart central control screen, calculator, smartwatch, GPS navigator, electronic photo, electronic billboard or sign, projector, etc.

[0100] The display device 900 includes the display substrate provided in any of the above embodiments. The display substrate may be an organic light-emitting diode display substrate or a quantum dot electroluminescent display substrate.

[0101] In addition, the display device 900 can also perform functions such as taking photos, recording videos, fingerprint recognition, and facial recognition. Accordingly, the display device 900 also includes at least one functional module for implementing the above functions, such as an under-display camera or an under-display fingerprint recognition sensor.

[0102] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A display panel, characterized in that, include: substrate; A light-emitting device layer is disposed on one side of the substrate. The light-emitting device layer includes a plurality of light-emitting units. Each light-emitting unit includes a first electrode, a light-emitting functional layer, and a second electrode that are sequentially stacked along a direction away from the substrate. A light extraction layer is disposed on the side of the second electrode opposite to the substrate; A light conditioning layer is located on the side of the light extraction layer opposite to the substrate, and the light conditioning layer includes multiple dielectric layers with different refractive indices; A cover plate is disposed on the side of the light-adjusting layer opposite to the substrate; The refractive indices of the plurality of dielectric layers are between those of the cover plate and the light extraction layer. Along the direction away from the substrate, the refractive index gradient of the plurality of dielectric layers decreases or increases. The difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer far from the cover plate and the refractive index of the cover plate. The difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer far from the light extraction layer and the refractive index of the light extraction layer.

2. The display panel according to claim 1, characterized in that, The refractive index of the dielectric layer is greater than or equal to 1.5 and less than or equal to 2.5; Preferably, the difference between the refractive index of the dielectric layer closest to the cover plate and the refractive index of the cover plate is equal to a first preset value; and / or, the difference between the refractive index of the dielectric layer closest to the light extraction layer and the refractive index of the light extraction layer is equal to a second preset value; Preferably, the first preset value is 0; and / or, the second preset value is 0.

3. The display panel according to claim 1, characterized in that, The material of the dielectric layer includes a light-transmitting material; Preferably, the extinction coefficient of the light-transmitting material for light in the wavelength range of 440nm to 780nm is equal to a third preset value; Preferably, the third preset value is 0; Preferably, the material of the dielectric layer includes an inorganic transparent material or an organic transparent material; Preferably, the material of the dielectric layer includes at least one of silicon dioxide, silicon nitride, and silicon oxynitride, and / or the material of the dielectric layer includes polymethyl methacrylate.

4. The display panel according to claim 1, characterized in that, The thickness of the light-modulating layer is greater than or equal to 5 μm and less than or equal to 8 μm; Preferably, the thickness of the dielectric layer is greater than or equal to 110 nm and less than or equal to 195 nm; Preferably, the different dielectric layers have the same thickness; Preferably, the thickness of the light extraction layer is greater than or equal to 50 nm and less than or equal to 90 nm; Preferably, the display panel further includes a support structure located between the substrate and the cover plate, the support structure, the substrate, and the cover plate forming an accommodating space, and the light-emitting device layer, the light extraction layer, and the light-adjusting layer located within the accommodating space; Preferably, the cross-sectional width of the support structure gradually decreases along the direction away from the substrate; Preferably, the cross-sectional shape of the support structure in the direction perpendicular to the substrate includes a trapezoid.

5. The display panel according to claim 1, characterized in that, It also includes a pixel definition layer, which is located between the substrate and the light extraction layer, and the pixel definition layer encloses a plurality of pixel openings, with at least a portion of the light-emitting unit located within the pixel openings; Preferably, the first electrode is located between the pixel definition layer and the substrate, the pixel opening exposes a portion of the first electrode, at least a portion of the light-emitting functional layer covers the first electrode, and the second electrode covers the light-emitting functional layer.

6. A display panel, characterized in that, include: substrate; A light-emitting device layer is disposed on one side of the substrate. The light-emitting device layer includes a plurality of light-emitting units. Each light-emitting unit includes a first electrode, a light-emitting functional layer, and a second electrode that are sequentially stacked along a direction away from the substrate. A light extraction layer is disposed on the side of the second electrode opposite to the substrate; A cover plate is located on the side of the light extraction layer opposite to the substrate; A support structure is provided, located between the substrate and the cover plate, the support structure, the substrate, and the cover plate forming a receiving space, and the light-emitting device layer and the light extraction layer are located within the receiving space; The light extraction layer and the cover plate are provided with a light conditioning layer, which is an air layer. The thickness of the light conditioning layer is greater than or equal to 8 μm and less than or equal to 0.7 mm along the direction perpendicular to the substrate.

7. The display panel according to claim 6, characterized in that, A transparent material layer is provided on the surface of the cover plate facing the substrate, and the refractive index of the transparent material layer is less than that of the cover plate; Preferably, the refractive index of the transparent material layer is greater than or equal to 1.3 and less than or equal to 1.5; Preferably, the thickness of the transparent material layer is greater than 0 and less than or equal to 8 μm; Preferably, the cover plate is made of glass.

8. A method for manufacturing a display panel, characterized in that, include: A light-emitting device layer is fabricated on a substrate. The light-emitting device layer includes a plurality of light-emitting units. Each light-emitting unit includes a first electrode, a light-emitting functional layer, and a second electrode that are sequentially stacked along a direction away from the substrate. A light extraction layer is prepared on the side of the second electrode opposite to the substrate; A light conditioning layer is prepared on the side of the light extraction layer away from the substrate, and the light conditioning layer includes multiple dielectric layers with different refractive indices. A cover plate is provided on the side of the light-modulating layer opposite to the substrate; The refractive indices of the plurality of dielectric layers are between those of the cover plate and the light extraction layer. Along the direction away from the substrate, the refractive index gradient of the plurality of dielectric layers decreases or increases. The difference between the refractive index of the dielectric layer near the cover plate and the refractive index of the cover plate is smaller than the difference between the refractive index of the dielectric layer far from the cover plate and the refractive index of the cover plate. The difference between the refractive index of the dielectric layer near the light extraction layer and the refractive index of the light extraction layer is smaller than the difference between the refractive index of the dielectric layer far from the light extraction layer and the refractive index of the light extraction layer.

9. The method for manufacturing a display panel according to claim 8, characterized in that, After the step of preparing the light conditioning layer on the side of the light extraction layer opposite to the substrate, the preparation method further includes: A support structure is provided on the periphery of the light-emitting device layer and the light extraction layer, and the surface of the support structure opposite to the substrate protrudes from the surface of the light extraction layer opposite to the substrate; Preferably, the step of fabricating a light conditioning layer on the side of the light extraction layer away from the substrate includes: sequentially fabricating multiple dielectric layers on the side of the light extraction layer away from the substrate, wherein the side surface of the dielectric layer contacts the support structure; Preferably, the step of providing a cover plate on the side of the light-adjusting layer away from the substrate includes: placing a cover plate on the side of the light-adjusting layer away from the substrate, and the support structure supporting the cover plate; Preferably, after the step of setting the cover plate on the side of the light-adjusting layer away from the substrate, the preparation method further includes: coating the surface of the support structure away from the light-emitting device layer with an adhesive to seal the display panel.

10. A display device, characterized in that, The display panel includes the display panel described in any one of claims 1 to 7, or the display panel prepared by the preparation method according to claim 8 or 9.

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