Display panel, preparation method thereof and display device

Abstract

Embodiments of the present disclosure provide a display panel and a manufacturing method thereof, and a display device, and relate to the technical field of display. The display panel comprises a substrate and a plurality of light emitting devices arranged on the substrate. The light emitting device comprises a first electrode, a light emitting layer, a second electrode and a light extraction layer arranged in a direction away from the substrate. The surface of the light extraction layer away from the second electrode is formed with a plurality of protrusions; the vertexes of two protrusions arranged adjacent in a first direction have a first distance in the first direction, and the first direction is perpendicular to the thickness direction of the substrate. The plurality of light emitting devices comprises a first light emitting device and a second light emitting device, the wavelength of the light emitted by the first light emitting device is greater than the wavelength of the light emitted by the second light emitting device, and the first distance of the light extraction layer corresponding to the first light emitting device is greater than the first distance of the light extraction layer corresponding to the second light emitting device. The display panel is used for display.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display panel, a method for manufacturing the same, and a display device. Background Technology

[0002] OLED (Organic Light Emitting Diode) display panels are widely used in display screens for mobile phones, tablets, automotive displays, etc. due to their advantages such as being all-solid-state, having fast response speed, and having a wide operating temperature range. Summary of the Invention

[0003] The purpose of this disclosure is to provide a display panel and its manufacturing method, as well as a display device, for improving color deviation problems.

[0004] To achieve the above objectives, the embodiments of this disclosure provide the following technical solutions: On one hand, a display panel is provided. The display panel includes a substrate and a plurality of light-emitting devices disposed on the substrate. Each light-emitting device includes a first electrode, a light-emitting layer, a second electrode, and a light-extraction layer stacked in a direction away from the substrate. A plurality of protrusions are formed on the surface of the light-extraction layer facing away from the second electrode; the vertices of two adjacent protrusions disposed in a first direction have a first distance along the first direction, which is perpendicular to the thickness direction of the substrate. The plurality of light-emitting devices includes a first light-emitting device and a second light-emitting device, wherein the wavelength of light emitted by the first light-emitting device is greater than the wavelength of light emitted by the second light-emitting device, and the first distance corresponding to the light-extraction layer of the first light-emitting device is greater than the first distance corresponding to the light-extraction layer of the second light-emitting device.

[0005] Understandably, when multiple protrusions are formed on the surface of the light extraction layer facing away from the second electrode, the surface of the light extraction layer facing away from the second electrode is relatively uneven, which can change the optical path and propagation direction and suppress total internal reflection. In this way, when the light emitted by the light-emitting layer is emitted to the surface of the light extraction layer facing away from the second electrode, a phenomenon similar to diffuse reflection can be formed. This can overcome the optical limitation of color shift caused by the microcavity effect, improve the color shift problem, and also improve the light extraction efficiency of the light extraction layer, thereby improving the efficiency of the light-emitting device. Furthermore, when the first distance corresponding to the light extraction layer of the first light-emitting device is greater than the first distance corresponding to the light extraction layer of the second light-emitting device, the arrangement period of the multiple protrusions in the light extraction layer of the first light-emitting device with a larger emission wavelength is larger, which can generate a relatively strong scattering intensity; the arrangement period of the multiple protrusions in the light extraction layer of the second light-emitting device with a smaller emission wavelength is smaller, which can generate a relatively weak scattering intensity. In this way, the scattering intensity of the light-emitting device can be better matched with the emission wavelength of the light-emitting device. Thus, the enhancement / weakening trend and amplitude of different colored light under the same viewing angle can be more consistent, which can alleviate the color shift problem and reduce the degree of color change with viewing angle.

[0006] In some embodiments, the plurality of protrusions are arranged periodically in the light extraction layer corresponding to a light-emitting device.

[0007] In some embodiments, the height of the protrusion in the light extraction layer of the first light-emitting device is greater than the height of the protrusion in the light extraction layer of the second light-emitting device.

[0008] In some embodiments, the bottom surface of the protrusion is a circular bottom surface or a near-circular bottom surface.

[0009] In some embodiments, the first distance is in the range of 500nm to 900nm.

[0010] In some embodiments, the height of the protrusion is in the range of 50nm to 100nm.

[0011] In some embodiments, the light extraction layer comprises a first organic material and a second organic material, wherein the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. The volume ratio of the first organic material to the second organic material in the light extraction layer of the first light-emitting device is greater than the volume ratio of the first organic material to the second organic material in the light extraction layer of the second light-emitting device.

[0012] In some embodiments, the difference in the coefficients of thermal expansion of the first organic material and the second organic material is greater than or equal to a set threshold; the set threshold is greater than or equal to 50 × 10⁻⁶. -6 K- ¹.

[0013] In some embodiments, the volume ratio of the first organic material to the second organic material in the light extraction layer is in the range of 1:9 to 9:1.

[0014] In some embodiments, the coefficient of thermal expansion of the first organic material is 12 × 10⁻⁶. -6 K - ¹~100×10 -6 K - Within the range of ¹.

[0015] In some embodiments, the coefficient of thermal expansion of the second organic material is 12 × 10⁻⁶. -6 K - ¹~100×10 -6 K - Within the range of ¹.

[0016] In some embodiments, the first organic material includes a bisspirofluorene material.

[0017] In some embodiments, the second organic material includes triphenylamine materials, 1,3,5 Triphenylbenzene materials, N Methylphthalimide materials and 2 Phenyl Isoindole 1,3 At least one of the diketone materials.

[0018] In some embodiments, the first organic material includes at least one of the structures shown in the following structural formulas (I-1) to (I-3).

[0019] , , .

[0020] In some embodiments, the second organic material includes at least one of the structures shown in the following structural formulas (II-1) to (II-3).

[0021] , , .

[0022] In some embodiments, the plurality of light-emitting devices further includes a third light-emitting device, wherein the wavelength of the light emitted by the third light-emitting device is less than the wavelength of the light emitted by the second light-emitting device; and the first distance corresponding to the light extraction layer of the third light-emitting device is less than the first distance corresponding to the light extraction layer of the second light-emitting device.

[0023] In some embodiments, the light extraction layer comprises a first organic material and a second organic material, wherein the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. The volume ratio of the first organic material to the second organic material in the light extraction layer of the third light-emitting device is less than the volume ratio of the first organic material to the second organic material in the light extraction layer of the second light-emitting device.

[0024] In some embodiments, the thickness of the light extraction layer is in the range of 10 nm to 1000 nm.

[0025] In some embodiments, at a 30° viewing angle, the color difference of the white light emitted by the display panel is in the range of 1.0 JNCD to 1.6 JNCD.

[0026] In some embodiments, at a 60° viewing angle, the color difference of the white light emitted by the display panel is in the range of 1.3 JNCD to 2.4 JNCD.

[0027] On the other hand, a display device is provided. The display device includes: a display panel as described in any of the above embodiments, and a driver chip. The driver chip is coupled to the display panel.

[0028] The beneficial effects of the above-described display device are the same as those of the display panel described in some of the above embodiments, and will not be repeated here.

[0029] In another aspect, a method for fabricating a display panel is provided. The method includes: providing a substrate; and forming a plurality of light-emitting devices on the substrate. Each light-emitting device includes: a first electrode, a light-emitting layer, a second electrode, and a light-extraction layer stacked along a direction away from the substrate. A plurality of protrusions are formed on the surface of the light-extraction layer facing away from the second electrode; the vertices of two adjacent protrusions arranged along a first direction have a first distance along the first direction, which is perpendicular to the thickness direction of the substrate. The plurality of light-emitting devices includes a first light-emitting device and a second light-emitting device, wherein the wavelength of light emitted by the first light-emitting device is greater than the wavelength of light emitted by the second light-emitting device, and the first distance corresponding to the light-extraction layer of the first light-emitting device is greater than the first distance corresponding to the light-extraction layer of the second light-emitting device.

[0030] The beneficial effects of the above-described method for preparing the display panel are the same as those of the display panels described in some of the above embodiments, and will not be repeated here.

[0031] In some embodiments, forming a plurality of light-emitting devices on the substrate includes: co-depositing a first organic material and a second organic material to form a light extraction layer for the light-emitting devices. The coefficient of thermal expansion of the first organic material is greater than that of the second organic material. During the formation of the light extraction layer of the first light-emitting device, the deposition rate of the first organic material is in a first ratio to the deposition rate of the second organic material; during the formation of the light extraction layer of the second light-emitting device, the deposition rate of the first organic material is in a second ratio to the deposition rate of the second organic material. The first ratio is greater than the second ratio. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0033] Figure 1 This is a structural diagram of a display device according to some embodiments; Figure 2 This is a structural diagram of a display panel according to some embodiments; Figure 3 This is a structural diagram of a light-emitting device according to some embodiments; Figure 4 This is a structural diagram of a display panel according to some other embodiments; Figure 5 This is a structural diagram of a display panel according to some other embodiments; Figure 6 A flowchart illustrating a method for manufacturing a display panel according to some embodiments; Figure 7 This is a structural diagram of the second electrode and the light extraction layer according to some embodiments; Figures 8A-8C This is a structural diagram of the light extraction layer according to some embodiments; Figure 9 This is a structural diagram of a display panel according to some other embodiments. Detailed Implementation

[0034] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0035] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0036] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0037] In describing some embodiments, the term "coupled" and its derivative expressions may be used. The term "coupled" indicates, for example, that two or more components have direct physical or electrical contact. The term "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0038] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0039] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0040] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0041] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable deviation range for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable deviation range for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable deviation range for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0042] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0043] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched areas shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the areas of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0044] It should be noted that, for example, 1 / 2 in the accompanying drawings of this disclosure refers to both component 1 and component 2, which can be referenced to that component. Figure 4 In this context, 100A / 100 indicates that the first light-emitting device 100A and the light-emitting device 100 can both be represented by this component. Other similar reference numerals appearing in the accompanying drawings also follow the above explanation.

[0045] like Figure 1 As shown, some embodiments of this disclosure provide a display device 300, which includes a display panel 200. The display device 300 is, for example, an OLED display device.

[0046] For example, such as Figure 1 As shown, the display device 300 also includes a driver chip 310. The driver chip 310 is coupled to the display panel 200. The driver chip 310 is used to input various signals required for displaying images to the display panel 200, such as control signals, power supply voltage signals, and data signals.

[0047] In addition, the display device 300 may also include an under-display camera and an under-display fingerprint sensor, enabling the display device 300 to perform various functions such as taking photos, recording videos, fingerprint recognition, or facial recognition.

[0048] The aforementioned display device 300 can be any display device that displays either moving (e.g., video) or stationary (e.g., still image) text or images. More specifically, the display device of the described embodiments is contemplated to be implemented in or associated with a variety of electronic devices, such as (but not limited to) mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 video players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer displays, etc.), navigators, cockpit controllers and / or displays, displays of camera views (e.g., displays of rearview cameras in vehicles), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging and aesthetic structures (e.g., displays of images of a piece of jewelry), etc.

[0049] In some embodiments, such as Figure 2 As shown, the display panel 200 includes a substrate 210.

[0050] For example, the material of the substrate 210 can be a rigid material, such as glass, to realize a rigid substrate display; or the material of the substrate 210 can also be a flexible material, such as polyimide (PI), to realize a flexible substrate display.

[0051] For example, the material of substrate 210 may include inorganic materials, such as soda-lime glass, quartz glass, or sapphire glass. Alternatively, the material of substrate 210 may also include organic materials, such as one or any combination of polymethyl methacrylate, polyvinyl alcohol, polyvinylphenol, polyethersulfone, polyimide, polyamide, polyacetal, polycarbonate, polyethylene terephthalate, and polyethylene naphthalate. Or, the material of substrate 210 may include both organic and inorganic materials.

[0052] In some embodiments, such as Figure 2 As shown, the display panel 200 also includes a plurality of light-emitting devices 100 disposed on the substrate 210.

[0053] For example, in the plurality of light-emitting devices 100, the arrangement direction of two adjacent light-emitting devices 100 may intersect (e.g., be perpendicular to) the thickness direction Y of the substrate 210.

[0054] In some examples, the light-emitting device 100 is an OLED light-emitting device. An OLED light-emitting device is a self-emissive light-emitting device, consisting of a film structure made of organic materials. Due to the inherent flexibility of organic materials, OLED light-emitting devices are well-suited for fabrication on flexible substrates, allowing for the design and production of a variety of optoelectronic products, offering significant advantages over inorganic materials. OLEDs can provide highly saturated colors, such as highly saturated red, green, and blue. Full-color display panels made with OLED light-emitting devices do not require an additional backlight and offer advantages such as vibrant colors, thinness, and flexibility.

[0055] In some examples, such as Figure 2 As shown, the display panel 200 also includes a pixel defining layer 220. The pixel defining layer 220 is disposed on one side of the substrate 210 and defines a plurality of openings Q arranged side by side. At least a portion of a light-emitting device 100 is disposed within one opening Q.

[0056] Here, at least a portion of a light-emitting device 100 is disposed within an opening Q. This can be understood as a light-emitting device 100 being disposed corresponding to an opening Q, and a portion or all of the light-emitting device 100 being disposed within its corresponding opening Q.

[0057] With the above settings, the pixel defining layer 220 can define the opening Q for forming the light-emitting device 100. In this way, the light emitted by the light-emitting device 100 can be emitted from a designated area of ​​the display panel 200, thus avoiding color crosstalk.

[0058] In some embodiments, such as Figure 2As shown, the light-emitting device 100 includes a first electrode 110, a light-emitting layer 130, and a second electrode 120 stacked in a direction away from the substrate 210.

[0059] In some examples, the first electrode 110 is the anode and the second electrode 120 is the cathode; in this case, the light-emitting device 100 can be called a positively positioned light-emitting device. In still other examples, the first electrode 110 is the cathode and the second electrode 120 is the anode; in this case, the light-emitting device 100 can be called an inverted light-emitting device.

[0060] In some examples, such as Figure 2 As shown, the second electrodes 120 of multiple light-emitting devices 100 are electrically connected to each other. By this arrangement, the second electrodes 120 of multiple light-emitting devices 100 can obtain the same reference voltage signal, which is, for example, a signal from the VSS signal line.

[0061] For example, in the first electrode 110 and the second electrode 120, the anode material can be a conductive metal oxide material, such as indium tin oxide (ITO) or indium zinc oxide (IZO). Alternatively, the anode can be a composite electrode containing multiple materials, such as ITO / Ag / ITO, Ag / IZO, CNT / ITO, CNT / IZO, GO / ITO, or GO / IZO, where Ag is silver, CNT is carbon nanotube, and GO is graphene oxide.

[0062] For example, in the first electrode 110 and the second electrode 120, the cathode material can be a metallic material, a metal oxide, or a metal alloy, such as aluminum (Al), silver (Ag), gold (Au), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium (Li), potassium (K), sodium (Na), tin (Sn), titanium (Ti), lead (Pb), samarium (Sm), yttrium (Y), indium tin oxide (ITO), magnesium silver alloy (Mg:Ag), ytterbium alloy (… Yb:Au), ytterbium silver alloy (Yb:Ag), lithium aluminum alloy (Li:Al), or lithium calcium magnesium alloy (Li:Ca:Al), etc.; or, the cathode material can be a multilayer material, such as magnesium / aluminum (Mg / Al), magnesium / silver (Mg / Ag), aluminum / silver (Al / Ag), aluminum / gold (Al / Au), ytterbium / gold (Yb / Au), ytterbium / silver (Yb / Ag), calcium / magnesium (Ca / Mg), calcium / silver (Ca / Ag), or barium / silver (Ba / Ag), etc.

[0063] Based on the above structure, the light-emitting principle of the light-emitting device 100 is as follows: the circuit connected through the first electrode 110 and the second electrode 120 (e.g., a pixel driving circuit 231, such as...) Figure 2 As shown, holes are injected into the light-emitting layer 130 by the anode and electrons are injected into the light-emitting layer 130 by the cathode. The injected electrons and holes form excitons (i.e., electron-hole pairs) in the light-emitting layer 130. The excitons return to the ground state through radiative transition and emit photons.

[0064] In some examples, such as Figure 2 As shown, the light-emitting device 100 includes a light-emitting layer 130. In some other examples, such as Figure 3 As shown, the light-emitting device 100 includes multiple light-emitting layers 130 stacked together. In this case, the stacking direction of the multiple light-emitting layers 130 can be the direction in which the first electrode 110 and the second electrode 120 are disposed opposite to each other. It should be noted that... Figure 3 The following is a simplified schematic diagram of the display panel 200 after removing all film layers except those related to the light-emitting device 100. Figure 4 and Figure 5 Similarly, I will not elaborate further.

[0065] For example, the material of the light-emitting layer 130 may include one or more of fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence materials. The fluorescent materials include, for example, one or more of DCM, DCJ, Alq3, and DPVPi; the phosphorescent materials include, for example, one or more of Pt7O7, PtOEP, FirPic, and Ir(ppy)3; and the thermally activated delayed fluorescence materials include, for example, one or more of DAR-DPTX, TPA-DMAC, and 4CzIPN.

[0066] In some embodiments, such as Figure 3 As shown, when the light-emitting device 100 includes multiple light-emitting layers 130, the light-emitting device 100 also includes a charge-generating unit 140, which is located between two adjacent light-emitting layers 130.

[0067] In some examples, such as Figure 3 As shown, the charge generation unit 140 includes an electron generation layer 141 and a hole generation layer 142 stacked together; the electron generation layer 141 is closer to the anode than the hole generation layer 142. Exemplarily, the material of the electron generation layer 141 includes an electron transport material and a metallic material. Exemplarily, the material of the hole generation layer 142 includes a hole transport material and a p-type dopant (PD).

[0068] Through the aforementioned charge generation unit 140, the multilayer light-emitting layers 130 can be sequentially connected in the vertical direction of the light-emitting surface. Moreover, in the stacked OLED light-emitting device, the charge generation unit 140 not only serves to connect the light-emitting layers 130, but also helps to improve the generation efficiency of charges (holes or electrons), which can have a significant impact on the performance of the light-emitting device 100.

[0069] In some embodiments, such as Figure 3 As shown, to improve the luminous efficiency of the light-emitting device 100, the light-emitting device 100 further includes a hole transport functional layer 150 located on the side of the light-emitting layer 130 near the anode, and / or an electron transport functional layer 160 located on the side of the light-emitting layer 130 near the cathode. The hole transport functional layer 150 includes, for example, at least one of a stacked hole injection layer 151 (HIL), a hole transport layer 152 (HTL), and an electron blocking layer 153 (EBL). The electron transport functional layer 160 includes, for example, at least one of a stacked electron injection layer 161 (EIL), an electron transport layer 162 (ETL), and a hole blocking layer 163 (EBL).

[0070] By setting up the hole injection layer 151, hole transport layer 152, electron blocking layer 153, electron injection layer 161, electron transport layer 162, and hole blocking layer 163, it is equivalent to setting up transition steps between the anode and the light-emitting layer 130, and between the cathode and the light-emitting layer 130, reducing the potential barrier height that carrier transitions need to overcome, and thus making the luminous efficiency higher.

[0071] In some examples, such as Figure 2 As shown, the display panel 200 further includes an array layer 230 disposed between the substrate 210 and the pixel defining layer 220. The array layer 230 includes a plurality of pixel driving circuits 231, wherein the pixel driving circuit 231 includes, for example, a plurality of transistor TFTs. Each pixel driving circuit 231 is electrically connected to a light-emitting device 100 (e.g., to a first electrode 110 of a light-emitting device 100) for driving the light-emitting device 100 to emit light.

[0072] For example, in the display panel 200, the pixel driving circuit 231 can generate a driving current. Each light-emitting device 100 can emit light under the driving action of the driving current generated by the corresponding pixel driving circuit 231. The light emitted by multiple light-emitting devices 100 cooperates with each other, thereby enabling the display panel 200 to achieve the display function.

[0073] In some examples, such as Figure 2 As shown, the display panel 200 also includes an encapsulation structure 240 disposed on the side of the pixel defining layer 220 and the plurality of light-emitting devices 100 away from the substrate 210.

[0074] In some examples, the encapsulation structure 240 employs thin-film encapsulation (TFE) technology. In this case, the encapsulation structure 240 can be a composite layer. For example, the encapsulation structure 240 may include a first sub-layer and a second sub-layer arranged sequentially along a direction away from the pixel defining layer 220 and the plurality of light-emitting devices 100. The material of the first sub-layer includes an organic material; the material of the second sub-layer includes an inorganic material. Exemplarily, the encapsulation structure 240 may also include a third sub-layer located between the first sub-layer and the pixel defining layer 220, the material of which includes an inorganic material. The aforementioned inorganic material is, for example, silicon nitride (SiOx) and / or silicon nitride (SiNy) (the values ​​of x and y are not limited), and the aforementioned organic material is, for example, an acrylate polymer or an epoxy resin, etc.

[0075] With the above configuration, the encapsulation structure 240 can cover the light-emitting device 100 to prevent moisture and oxygen from the external environment from entering the display panel 200 and damaging the materials (e.g., organic materials) in the light-emitting device 100, thereby shortening the lifespan of the display panel 200.

[0076] In some examples, such as Figure 2 As shown, based on the direction of light emission, the display panel 200 can be classified into top-emitting display panels (also known as top-emitting display panels), bottom-emitting display panels (also known as bottom-emitting display panels), and double-sided emitting display panels (also known as double-sided emitting display panels). Among them, as... Figure 2 As shown, in a bottom-emitting display panel, the light emitted from the light-emitting layer 130 of the light-emitting device 100 exits from the substrate 210 side. In a top-emitting display panel, the light emitted from the light-emitting layer 130 of the light-emitting device 100 exits from the side away from the substrate 210. In a double-sided emitting display panel, the light emitted from the light-emitting layer 130 of the light-emitting device 100 can exit from both the side away from the substrate 210 and the side of the substrate 210, enabling the display panel 200 to have a double-sided display function.

[0077] In some examples, in the light-emitting device 100 of the top-emitting display panel, the first electrode 110 is an electrode with a certain reflective function and can be used as a reflective layer (e.g., a metal reflective layer). In this way, a resonant cavity (also called a microcavity) can be formed between the second electrode 120 (e.g., a metal cathode) and the first electrode 110, so that constructive interference and / or destructive interference exist during the light emission process, forming a microcavity effect, which can increase the light emission efficiency of the light-emitting device 100.

[0078] In some cases, as the viewing angle changes, the distance between the first electrode 110 and the second electrode 120 (which can also be understood as the cavity length of the microcavity) will change accordingly, resulting in significant differences in brightness and color observed under different viewing angles, causing color shift. This means that the color and brightness of the light become angle-dependent, which will affect product performance.

[0079] In some examples, in the light-emitting device 100 of the top-emitting display panel, if the incident angle value is greater than a certain angle value when the light emitted by the light-emitting layer 130 is incident on other film layers, total internal reflection will occur at the interface of other film layers, so that some light cannot be emitted and cannot be utilized, which may reduce the light emission efficiency.

[0080] In some embodiments, such as Figure 4 As shown, the light-emitting device 100 further includes a light extraction layer 170 disposed on the side of the second electrode 120 away from the light-emitting layer 130. That is, the first electrode 110, the light-emitting layer 130, the second electrode 120 and the light extraction layer 170 can be stacked in a direction away from the substrate 210.

[0081] For example, combined Figure 2 ,like Figure 4 As shown, when the display panel 200 includes the encapsulation structure 240, the light extraction layer 170 can be disposed between the second electrode 120 and the encapsulation structure 240.

[0082] In some examples, the material of the light extraction layer 170 includes a high refractive index material. Exemplarily, in addition to a high refractive index material, the material of the light extraction layer 170 may also include a low refractive index material.

[0083] By setting the light extraction layer 170, the optical path and propagation direction can be changed, which can overcome the optical limitation of color shift caused by the microcavity effect to a certain extent, so as to improve the color shift problem. It can also suppress the total internal reflection phenomenon of light at the interface of other film layers, so as to improve the light extraction efficiency.

[0084] In some embodiments, such as Figure 4 As shown, the thickness L of the light extraction layer 170 is in the range of 10nm to 1000nm.

[0085] For example, the thickness L of the light extraction layer 170 is in the range of 20 nm to 150 nm. Also for example, the thickness L of the light extraction layer 170 is in the range of 30 nm to 120 nm. Still for example, the thickness L of the light extraction layer 170 is in the range of 40 nm to 90 nm.

[0086] For example, the thickness L of the light extraction layer 170 can be 10nm, 20nm, 30nm, 40nm, 50nm, 56nm, 60nm, 70nm, 80nm, 90nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, or 1000nm, etc.

[0087] When the thickness L of the light extraction layer 170 is greater than or equal to 10 nm, the light extraction layer 170 has a certain thickness, which is beneficial to improving the effect of the light extraction layer 170 in improving color deviation and increasing light extraction efficiency. When the thickness L of the light extraction layer 170 is less than or equal to 1000 nm, the thickness L of the light extraction layer 170 is relatively small, which can make the thickness of the light-emitting device 100 smaller, which is beneficial to achieving the thinning of the display panel 200.

[0088] In some examples, the light extraction layer 170 in the light-emitting device 100 does not significantly improve color shift.

[0089] Based on this, such as Figure 4 As shown, some embodiments of this disclosure provide a display panel 200. In this display panel 200, a plurality of protrusions 171 are formed on the surface of the light extraction layer 170 facing away from the second electrode 120; the vertices 1711 of two adjacent protrusions 171 are separated by a first distance D along the first direction X, the first direction X being perpendicular to the thickness direction Y of the substrate 210.

[0090] The plurality of light-emitting devices 100 include a first light-emitting device 100A and a second light-emitting device 100B. The wavelength of the light emitted by the first light-emitting device 100A is greater than the wavelength of the light emitted by the second light-emitting device 100B. The first distance D1 corresponding to the light extraction layer 170A of the first light-emitting device 100A is greater than the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B.

[0091] For example, the first light-emitting device 100A can be used to emit red light, and the second light-emitting device 100B can be used to emit green light. Also for example, the first light-emitting device 100A can be used to emit red light, and the second light-emitting device 100B can be used to emit blue light. Also for example, the first light-emitting device 100A can be used to emit red light, and the second light-emitting device 100B can be used to emit yellow light.

[0092] In some examples, the above-mentioned display panel 200 is a top-emitting display panel.

[0093] Here, the vertex of the protrusion 171 refers to the point with the largest distance from the second electrode 120 among the multiple points included on the surface of the protrusion 171 away from the second electrode 120 (which can also be understood as the outer surface of the protrusion 171). In some examples, the surfaces of the multiple protrusions 171 arranged along the first direction X are connected to form a resonant waveform surface or a resonant waveform-like surface. In this case, the position of the vertex of the protrusion 171 corresponds to the position of the peak of the resonant waveform surface or the resonant waveform-like surface.

[0094] The vertices 1711 of two protrusions 171 arranged adjacent to each other along the first direction X have a first distance D along the first direction X. This can be understood as follows: among the multiple protrusions 171 of a light extraction layer 170, there are two protrusions 171 arranged adjacent to each other along the first direction X, and the vertices of these two protrusions 171 have a first distance D along the first direction X.

[0095] For example, a transmission electron microscope (TEM) can be used to inspect the cross-sectional morphology of the light extraction layer 170A of the first light-emitting device 100A and the light extraction layer 170B of the second light-emitting device 100B, respectively, to obtain the first distance D1 corresponding to the light extraction layer 170A of the first light-emitting device 100A and the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B. Of course, other methods can also be used, and this disclosure does not limit them.

[0096] Understandably, when multiple protrusions 171 are formed on the surface of the back-facing second electrode 120 of the light extraction layer 170, the surface of the back-facing second electrode 120 of the light extraction layer 170 is less smooth, which can change the optical path and propagation direction and suppress total internal reflection. In this way, when the light emitted by the light-emitting layer 130 is emitted to the surface of the back-facing second electrode 120 of the light extraction layer 170, a phenomenon similar to diffuse reflection can be formed. This can overcome the color shift optical limitation caused by the microcavity effect, improve the color shift problem, and also improve the light extraction efficiency of the light extraction layer 170, thereby improving the efficiency of the light-emitting device 100. For example, the external quantum efficiency of the light-emitting device 100 can be increased to more than 20%.

[0097] Furthermore, when the first distance D1 corresponding to the light extraction layer 170A of the first light-emitting device 100A is greater than the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B, the arrangement period of the multiple protrusions 171A in the light extraction layer 170A of the first light-emitting device 100A, which has a larger emission wavelength, is larger, and can generate a relatively strong scattering intensity; while the arrangement period of the multiple protrusions 171B in the light extraction layer 170A of the second light-emitting device 100B, which has a smaller emission wavelength, is smaller, and can generate a relatively weak scattering intensity. In this way, the scattering intensity of the light-emitting device 100 can be better matched with the emission wavelength of the light-emitting device 100. Thus, the enhancement / weakening trend and amplitude of different colored light under the same viewing angle can be more consistent, which can alleviate the color shift problem and reduce the degree of color change with viewing angle.

[0098] In some embodiments, in the light extraction layer 170 corresponding to a light-emitting device 100, a plurality of protrusions 171 are arranged periodically.

[0099] In other words, multiple protrusions 171 in the light extraction layer 170 corresponding to a light-emitting device 100 can form a periodically arranged texture, which is equivalent to setting a periodic pattern on the light extraction layer 170.

[0100] By setting it in this way, the multiple protrusions 171 in the light extraction layer 170 corresponding to a light-emitting device 100 can be arranged in a more regular manner, and the first spacing D between two adjacent protrusions 171 can be more consistent, which can improve the effect of the light extraction layer 170 in improving color shift.

[0101] In some embodiments, the thickness of the light extraction layer 170A of the first light-emitting device 100A is greater than the thickness of the light extraction layer 170B of the second light-emitting device 100B.

[0102] Here, the thickness of the light extraction layer 170A can be understood as the dimension of the light extraction layer 170 along the thickness direction Y of the substrate 210. It should be understood that when the light extraction layer 170 includes multiple protrusions 171, the light extraction layer 170 may have multiple different thicknesses. In this case, the thickness of the light extraction layer 170 can be the maximum dimension of the light extraction layer 170 along the thickness direction Y of the substrate 210.

[0103] When the thickness of the light extraction layer 170A of the first light-emitting device 100A is greater than the thickness of the light extraction layer 170B of the second light-emitting device 100B, the microcavity resonance peak and emission peak of the first light-emitting device 100A and the second light-emitting device 100B can be better matched at the positive viewing angle, which is beneficial to improving the front light emission efficiency and light extraction rate. In some cases, it can optimize the front white balance and obtain a higher microcavity Q value.

[0104] In practical applications, the thickness of the light extraction layer 170 of different light-emitting devices 100 can be set according to the color shift of the light-emitting device 100 at large angles and the front light extraction. For example, by setting the light extraction layer 170 of different light-emitting devices 100, the Q value of the light-emitting device 100 can be kept within a suitable range, thereby reducing the front efficiency loss of the light-emitting device 100 and improving the color shift problem at large angles.

[0105] In some embodiments, such as Figure 4 As shown, the height H1 of the protrusion 171A in the light extraction layer 170A of the first light-emitting device 100A is greater than the height H2 of the protrusion 171B in the light extraction layer 170B of the second light-emitting device 100B.

[0106] Here, the height H of the protrusion 171 can be understood as the maximum dimension of the protrusion 171 along the thickness direction Y of the substrate 210.

[0107] With this configuration, the relative size relationship of the height H of the protrusion 171 of the light extraction layer 170 in the first light-emitting device 100A and the second light-emitting device 100B is consistent with the relative size relationship of the emission wavelength in the first light-emitting device 100A and the second light-emitting device 100B. In this way, the scattering intensity of the light-emitting device 100 can be better matched with the emission wavelength of the light-emitting device 100. Thus, the trend and magnitude of the enhancement / weakening of different colored light under the same viewing angle can be more consistent, which can alleviate the color shift problem and reduce the degree of color change with viewing angle.

[0108] The morphology and dimensions of the protrusion 171 in the light extraction layer 170 will be described below by way of example, but it should be understood that the ideas of this disclosure are not limited thereto.

[0109] In some embodiments, combined with Figure 4 The bottom surface of the protrusion 171 is a circular bottom surface or a near-circular bottom surface.

[0110] In some examples, the light extraction layer 170 includes a layered main body 172, and a plurality of protrusions 171 may be integrally formed on the surface of the main body 172 away from the second electrode 120. In this case, the bottom surface of the protrusions 171 can be the interface between the main body 172 and the protrusions 171.

[0111] Here, a near-circular base refers to a base that resembles a circle but is not quasi-circular, such as an elliptical base. In some examples, a near-circular base can be understood as a base whose length-to-width ratio is less than or equal to a first preset threshold. The length of the near-circular base is the distance between the two boundary points of the near-circular base whose connecting lines pass through the geometric center and have the longest distance. The width of the near-circular base is the distance between the two boundary points of the near-circular base whose connecting lines pass through the geometric center and have the shortest distance. The aforementioned first preset threshold is, for example, 1.1, 1.2, 1.3, 1.5, or 2.

[0112] When the bottom surface of the protrusion 171 is a circular or near-circular bottom surface, the shape of the protrusion 171 is more consistent with the shape of the protrusion formed in some processes. For example, the shape of the protrusion 171 is more consistent with the shape of the protrusion formed in the vapor deposition process. In this way, the process difficulty of forming the protrusion 171 can be reduced.

[0113] In some embodiments, such as Figure 4 As shown, the first distance D is in the range of 500nm~900nm.

[0114] For example, the first distance can be 500nm, 520nm, 550nm, 580nm, 600nm, 630nm, 650nm, 680nm, 700nm, 720nm, 750nm, 770nm, 800nm, 820nm, 850nm, 880nm or 900nm, etc.

[0115] When the first distance D is in the range of 500nm to 900nm, the first distance D is well matched with the emission wavelength of the light-emitting device 100, which can improve the scattering effect of the light extraction layer 170.

[0116] In some embodiments, such as Figure 4 As shown, the height H of the protrusion 171 is in the range of 50nm to 100nm.

[0117] As one possible way to obtain this information, the height H of the protrusion 171 can be measured using transmission electron microscopy (TEM) and / or atomic force microscopy (AFM).

[0118] For example, the height H of the protrusion 171 can be 50nm, 55nm, 60nm, 65nm, 70nm, 72nm, 75nm, 80nm, 85nm, 90nm, 95nm or 100nm, etc.

[0119] When the height H of the protrusion 171 is greater than or equal to 50 nm, the protrusion 171 has a certain height, which is beneficial to improving the effect of the height H of the protrusion 171 on the scattering effect of the light extraction layer 170. When the height H of the protrusion 171 is less than or equal to 100 nm, the height H of the protrusion 171 is relatively low, which is beneficial to improving the morphological stability of the protrusion 171, thereby improving the effect of the protrusion 171 on improving color shift and improving device efficiency.

[0120] The material of the light extraction layer 170 will be described below as an example.

[0121] In some examples, the light extraction layer 170 in the light-emitting device 100 is prepared by methods such as spin coating, and / or the material of the light extraction layer 170 includes a polymer material with a high molecular weight, which reduces the density and uniformity of the formed light extraction layer 170 and may form voids.

[0122] In some embodiments, such as Figure 4 As shown, the light extraction layer 170 is made of a first organic material and a second organic material, and the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. The volume ratio of the first organic material to the second organic material in the light extraction layer 170A of the first light-emitting device 100A is greater than that in the light extraction layer 170B of the second light-emitting device 100B.

[0123] For example, in the light extraction layer 170A of the first light-emitting device 100A, the volume percentage of the first organic material is 80%, and the volume percentage of the second organic material is 20%, with a volume ratio of 4:1. In the light extraction layer 170B of the second light-emitting device 100B, the volume percentage of the first organic material is 50%, and the volume percentage of the second organic material is 50%, with a volume ratio of 1:1. The volume ratio of the first organic material to the second organic material in the light extraction layer 170A of the first light-emitting device 100A is greater than the volume ratio of the first organic material to the second organic material in the light extraction layer 170B of the second light-emitting device 100B.

[0124] In some examples, the material of the light extraction layer 170 is composed of a first organic material and a second organic material. In still other examples, the material of the light extraction layer 170 also includes other materials besides the first organic material and the second organic material.

[0125] In some examples, when the material of the light extraction layer 170 includes a first organic material and a second organic material, a protrusion 171 may be formed on the surface of the light extraction layer 170 facing away from the second electrode 120, and the vertices 1711 of two adjacent protrusions 171 disposed along the first direction X have the aforementioned first distance D. Furthermore, the first distance D corresponding to the light extraction layer 170 is positively correlated with the volume ratio of the first organic material and the second organic material. That is, the larger the volume ratio of the first organic material and the second organic material, the larger the first distance D corresponding to the light extraction layer 170.

[0126] Understandably, when the light extraction layer 170 is made of a first organic material and a second organic material, a high-temperature process (e.g., co-evaporation) can be used to form the light extraction layer 170 using the first and second organic materials. This improves the uniformity and density of the formed light extraction layer 170, which is beneficial for improving product quality. Moreover, when the coefficient of thermal expansion of the first organic material is greater than that of the second organic material, there will be a certain residual strain during the process of heating, expanding, and then cooling the first and second organic materials. This results in a patterned surface micro-nano morphology on the surface of the formed light extraction layer 170, i.e., the formation of multiple protrusions 171. This allows the surface micro-nano morphology of the formed light extraction layer 170 to be controlled. In this way, multiple protrusions 171 can be used to improve color shift problems, increase device efficiency, and improve the feasibility of forming multiple protrusions 171.

[0127] When the volume ratio of the first organic material to the second organic material in the light extraction layer 170A of the first light-emitting device 100A is greater than that in the light extraction layer 170B of the second light-emitting device 100B, during the formation of the light extraction layer 170A of the first light-emitting device 100A, the larger volume ratio of the first organic material to the second organic material can be utilized to generate relatively large residual stress in the light extraction layer 170A of the first light-emitting device 100A, forming a light extraction layer 170A with a relatively larger corresponding first distance D1, and increasing the height of the protrusion 171A. The degree H1 is relatively large; and during the formation of the light extraction layer 170B of the second light-emitting device 100B, the relatively small volume ratio of the first organic material to the second organic material can be used to generate relatively small residual stress in the light extraction layer 170B of the second light-emitting device 100B, forming a light extraction portion 170B with a relatively small corresponding first distance D2, and making the height H2 of the protrusion 171B smaller; thus, as described in the previous part, the trend and magnitude of the enhancement / weakening of different colors of light under the same viewing angle can be made more consistent, which can alleviate the problem of color shift and reduce the degree of color change with viewing angle.

[0128] In some embodiments, combined with Figure 4 The difference in the coefficients of thermal expansion between the first organic material and the second organic material is greater than or equal to a set threshold. The set threshold is greater than or equal to 50 × 10⁻⁶. -6 K - ¹.

[0129] For example, the threshold can be set to 50×10 -6 K - ¹、52×10 -6 K - ¹、54×10 -6 K - ¹、55×10 -6 K - ¹、58×10 -6 K - ¹、60×10 -6 K - ¹、65×10 -6 K - ¹、70×10 -6 K - ¹、80×10 -6 K - ¹or 88×10 -6 K - ¹ etc.

[0130] For example, the coefficient of thermal expansion of the first organic material is 80 × 10⁻⁶. -6 K - ¹, The coefficient of thermal expansion of the second organic material is 25 × 10⁻⁶. -6 K - ¹, The difference in the coefficients of thermal expansion between the first organic material and the second organic material is 55 × 10⁻⁶. -6 K - ¹.

[0131] By setting it as described above, the difference in the coefficients of thermal expansion between the first organic material and the second organic material can be made larger, which can increase the mismatch between the coefficients of thermal expansion of the first organic material and the second organic material. In this way, during the process of heating, expanding and cooling the first organic material and the second organic material, a large residual strain can be generated, which is conducive to forming the difference between the first distance D corresponding to the light extraction layer 170 of the first light-emitting device 100A and the second light-emitting device 100B, and is also conducive to forming the difference between the height H of the protrusion 171 of the light extraction layer 170 of the first light-emitting device 100A and the second light-emitting device 100B.

[0132] In some embodiments, combined with Figure 4 The coefficient of thermal expansion of the first organic material is 12 × 10⁻⁶. -6 K - ¹~100×10- 6 K - Within the range of ¹.

[0133] For example, the coefficient of thermal expansion of the first organic material can be 12 × 10⁻⁶. -6 K - ¹、20×10 -6 K - ¹、30×10 - 6 K - ¹、40×10 -6 K - ¹、50×10 -6 K - ¹、60×10 -6 K - ¹、70×10 -6 K - ¹、72×10 -6 K - ¹、80×10 -6 K - ¹、90×10 -6 K - ¹or 100×10 -6 K - ¹ etc.

[0134] By setting it in this way, the coefficient of thermal expansion of the first organic material can be matched with the coefficient of thermal expansion of a variety of organic materials, which can increase the range of options for the first organic material and reduce the material cost of forming the light extraction layer 170 to a certain extent.

[0135] In some embodiments, combined with Figure 4 The coefficient of thermal expansion of the second organic material is 12 × 10⁻⁶. -6 K - ¹~100×10 - 6 K - Within the range of ¹.

[0136] For example, the coefficient of thermal expansion of the second organic material can be 12 × 10⁻⁶. -6 K - ¹、20×10 -6 K - ¹、25×10 - 6 K - ¹、30×10 -6 K - ¹、40×10 -6 K - ¹、50×10 -6 K -¹、60×10 -6 K - ¹、70×10 -6 K - ¹、80×10 -6 K - ¹、90×10 -6 K - ¹or 100×10 -6 K - ¹ etc.

[0137] By setting it in this way, the coefficient of thermal expansion of the second organic material can be matched with the coefficient of thermal expansion of a variety of organic materials, which can increase the range of options for the second organic material and reduce the material cost of forming the light extraction layer 170 to a certain extent.

[0138] In some embodiments, combined with Figure 4 In the material of the light extraction layer 170, the volume ratio of the first organic material and the second organic material is in the range of 1:9 to 9:1.

[0139] For example, in the material of the light extraction layer 170, the volume ratio of the first organic material and the second organic material can be 1:9, 2:8, 3:7, 3.5:6.5, 4:6, 5:5, 6:4, 7:3, 8:2 or 9:1, etc.

[0140] By setting it in this way, the volume ratio of the first organic material and the second organic material can be adjusted within a large range, thereby allowing a large range to be adjusted for the difference between the volume percentage of the first organic material and the volume percentage of the second organic material in the light extraction layer 170. This is beneficial for realizing the difference between the first distance D corresponding to the light extraction layers 170 of the first light-emitting device 100A and the second light-emitting device 100B, and also beneficial for forming the difference between the height H of the protrusions 171 of the light extraction layers 170 of the first light-emitting device 100A and the second light-emitting device 100B.

[0141] In some embodiments, combined with Figure 4 The first type of organic material includes bispirofluorene materials.

[0142] For example, bisspirofluorene materials include bisspirofluorene, and / or compounds obtained by substituting one or more hydrogen atoms in bisspirofluorene. The groups used to substitute the hydrogen atoms are, for example, C1-C5 hydrocarbon groups, C1-C10 hydrocarbon groups, phenyl groups, C6-C10 aromatic groups, or C6-C10 heteroaryl groups.

[0143] For example, the structure of a double filament can be as shown in the following formula.

[0144] .

[0145] Understandably, on the one hand, dual-spirofluorene materials have a high coefficient of thermal expansion, which is beneficial for achieving the height difference of the protrusions 171 in the light extraction layer 170 of the first light-emitting device 100A and the second light-emitting device 100B; on the other hand, dual-spirofluorene materials have good film-forming properties and high morphological stability, which is beneficial for improving the film-forming properties and stability of the formed light extraction layer 170.

[0146] In some examples, the first organic material includes a triazine group.

[0147] In some embodiments, combined with Figure 4 The first organic material includes at least one of the structures shown in the following structural formulas (I-1) to (I-3).

[0148] , , .

[0149] On the one hand, the compound shown in the above structure has a high coefficient of thermal expansion, which is beneficial to achieving the height difference of the protrusions 171 in the light extraction layer 170 of the first light-emitting device 100A and the second light-emitting device 100B; on the other hand, the compound shown in the above structure has a high refractive index and high thermal stability, which is beneficial to improving the light extraction efficiency and stability of the formed light extraction layer 170.

[0150] In some embodiments, combined with Figure 4 The second organic material includes triphenylamine materials, 1,3,5 Triphenylbenzene materials, N Methylphthalimide materials and 2 Phenyl Isoindole 1,3 At least one of the diketone materials.

[0151] For example, triphenylamine materials include triphenylamine, and / or compounds obtained by substituting one or more hydrogen atoms in triphenylamine. The groups used to substitute the hydrogen atoms are, for example, C1-C5 hydrocarbon groups, C1-C10 hydrocarbon groups, phenyl groups, C6-C10 aromatic groups, or C6-C10 heteroaryl groups.

[0152] For example, 1, 3, 5 Triphenylbenzene materials include 1, 3, 5 Triphenylbenzene, and / or 1,3,5 Compounds obtained by substituting one or more hydrogen atoms in triphenylbenzene. The groups used to replace the hydrogen atoms are, for example, C1-C5 hydrocarbon groups, C1-C10 hydrocarbon groups, phenyl groups, C6-C10 aromatic groups, or C6-C10 heteroaryl groups.

[0153] For example, N Methylphthalimide materials include N Methylphthalimide, and / or, N A compound obtained by substituting one or more hydrogen atoms in methylphthalimide. The substituent groups are, for example, C1-C5 hydrocarbon groups, C1-C10 hydrocarbon groups, phenyl groups, C6-C10 aromatic groups, or C6-C10 heteroaryl groups.

[0154] For example, 2 Phenyl Isoindole 1,3 Diketone materials include 2 Phenyl Isoindole 1,3 diketone, and / or, 2 Phenyl Isoindole 1,3 Compounds obtained by substituting one or more hydrogen atoms in a diketone. The groups used to substitute the hydrogen atoms are, for example, C1-C5 hydrocarbon groups, C1-C10 hydrocarbon groups, phenyl groups, C6-C10 aromatic groups, or C6-C10 heteroaryl groups.

[0155] For example, N The structure of methylphthalimide can be shown in the following formula.

[0156] .

[0157] In some embodiments, combined with Figure 4 The second organic material includes at least one of the structures shown in the following structural formulas (II-1) to (II-3).

[0158] , , .

[0159] The structure shown in formula (II-2) can be triphenylamine. The structure shown in formula (II-3) can be 1,3,5 Triphenylbenzene. The structure shown in formula (II-1) can be 2 Phenyl Isoindole 1,3 Diketone.

[0160] Understandably, on the one hand, triphenylamine materials, 1,3,5 Triphenylbenzene materials, N Methylphthalimide materials and 2 Phenyl Isoindole 1,3 Diketone materials have a low coefficient of thermal expansion, which is beneficial for achieving a height difference between the protrusions 171 in the light extraction layer 170 of the first light-emitting device 100A and the second light-emitting device 100B; on the other hand, triphenylamine materials, 1,3,5 Triphenylbenzene materials, N Methylphthalimide materials and 2 Phenyl Isoindole 1,3 Diketone materials have good film-forming properties and thermal stability, which are beneficial to improving the film-forming properties and stability of the formed photoextraction layer 170.

[0161] The following description will exemplarily illustrate the situation of other light-emitting devices in the display panel 200.

[0162] In some embodiments, such as Figure 5 As shown, the plurality of light-emitting devices 100 also includes a third light-emitting device 100C, the wavelength of the light emitted by the third light-emitting device 100C is less than the wavelength of the light emitted by the second light-emitting device 100B; the first distance D3 corresponding to the light extraction layer 170C of the third light-emitting device 100C is less than the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B.

[0163] For an understanding of the meaning and detection method of the first distance D3 corresponding to the light extraction layer 170C of the third light-emitting device 100C, please refer to the relevant content mentioned above, and it will not be repeated here.

[0164] For example, the first light-emitting device 100A can be used to emit red light, the second light-emitting device 100B can be used to emit green light, and the third light-emitting device 100C can be used to emit blue light.

[0165] Understandably, when the first distance D3 corresponding to the light extraction layer 170C of the third light-emitting device 100C is less than the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B, the arrangement period of the multiple protrusions 171B in the light extraction layer 170B of the second light-emitting device 100B, which has a larger emission wavelength, is larger and can generate a relatively strong scattering intensity; the arrangement period of the multiple protrusions 171B in the light extraction layer 170C of the third light-emitting device 100C, which has a smaller emission wavelength, is smaller and can generate a relatively weak scattering intensity. In this way, the scattering intensity of the light-emitting device 100 can be better matched with the emission wavelength of the light-emitting device 100. Thus, the enhancement / weakening trend and amplitude of different colored light under the same viewing angle are more consistent, which can alleviate the color shift problem and reduce the degree of color change with viewing angle.

[0166] In some embodiments, such as Figure 5 As shown, the volume ratio of the first organic material to the second organic material in the light extraction layer 170C of the third light-emitting device 100C is less than the volume ratio of the first organic material to the second organic material in the light extraction layer 170B of the second light-emitting device 100B.

[0167] For an understanding of the optional materials, coefficients of thermal expansion, etc. of the first and second organic materials, please refer to the content in the preceding sections, and we will not repeat it here.

[0168] With the above configuration, during the formation of the light extraction layer 170B of the second light-emitting device 100B, the larger volume ratio of the first organic material to the second organic material can be used to generate relatively large residual stress in the light extraction layer 170B of the second light-emitting device 100B, forming a light extraction layer 170B with a relatively large first distance D2, and making the height H2 of the protrusion 171B larger; while during the formation of the light extraction layer 170C of the third light-emitting device 100C, the smaller volume ratio of the first organic material to the second organic material can be used to generate relatively small residual stress in the light extraction layer 170C of the third light-emitting device 100C, forming a light extraction portion 170C with a relatively small first distance D3, and making the height H3 of the protrusion 171C smaller; thus, the enhancement / weakening trend and amplitude of different colored light under the same viewing angle can be made more consistent, which can alleviate the color shift problem and reduce the degree of color change with viewing angle.

[0169] As described above, the first light-emitting device 100A can be used to emit red light, the second light-emitting device 100B can be used to emit green light, and the third light-emitting device 100C can be used to emit blue light. In this case, the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C can form a device in the display panel 200 that emits white light, so that the display panel 200 can be used to emit white light.

[0170] The following will provide an exemplary description of the color difference of white light emitted by the display panel 200 based on some embodiments of the present disclosure.

[0171] In some embodiments, such as Figure 5 As shown, at a 30° viewing angle, the color difference of the white light emitted by the display panel 200 is in the range of 1.0 JNCD to 1.6 JNCD.

[0172] For example, at a 30° viewing angle, the color difference of the white light emitted by the display panel 200 can be 1.0 JNCD, 1.1 JNCD, 1.2 JNCD, 1.25 JNCD, 1.3 JNCD, 1.4 JNCD, 1.5 JNCD, or 1.6 JNCD, etc.

[0173] Among them, the color difference that the human eye can perceive is JNCD (Just Noticeable Color Difference). In other words, the smallest unit of color change that the human eye can distinguish is 1 JNCD, where 1 JNCD = 0.004. The smaller the color difference of the white light mentioned above, the smaller the amount of color change, indicating that the angle dependence of the emitted light wavelength of the display panel 200 is suppressed better.

[0174] When the color difference of the white light emitted by the display panel 200 is within the range of 1.0 JNCD to 1.6 JNCD at a 30° viewing angle, the chromaticity change of the light emitted by the light-emitting device 100 is small, the angle dependence of the wavelength of the light emitted by the display panel 200 can be well suppressed, and the color shift problem can be alleviated.

[0175] In some embodiments, such as Figure 5 As shown, at a 60° viewing angle, the color difference of the white light emitted by the display panel 200 is in the range of 1.3 JNCD to 2.4 JNCD.

[0176] For example, at a 60° viewing angle, the color difference of the white light emitted by the display panel 200 can be 1.3 JNCD, 1.4 JNCD, 1.5 JNCD, 1.6 JNCD, 1.7 JNCD, 1.8 JNCD, 1.9 JNCD, 2.0 JNCD, 2.1 JNCD, 2.2 JNCD, 2.3 JNCD, or 2.4 JNCD, etc.

[0177] At a 60° viewing angle, when the color difference of the white light emitted by the display panel 200 is within the range of 1.3 JNCD to 2.4 JNCD, the chromaticity change of the light emitted by the light-emitting device 100 is small, the angle dependence of the wavelength of the light emitted by the display panel 200 can be well suppressed, and the color shift problem can be alleviated.

[0178] Some embodiments of this disclosure also provide a method for manufacturing a display panel 200. Combined with... Figure 4 ,like Figure 6 As shown, the preparation method includes S1~S2.

[0179] S1: Provide substrate 210.

[0180] S2: Multiple light-emitting devices 100 are formed on the substrate 210.

[0181] The light-emitting device 100 includes a first electrode 110, a light-emitting layer 130, a second electrode 120, and a light extraction layer 170 stacked along a direction away from the substrate 210. A plurality of protrusions 171 are formed on the surface of the light extraction layer 170 facing away from the second electrode 120. The apexes 1711 of two adjacent protrusions 171 are separated by a first distance D along the first direction X, which is perpendicular to the thickness direction Y of the substrate 210. The plurality of light-emitting devices 100 include a first light-emitting device 100A and a second light-emitting device 100B. The wavelength of light emitted by the first light-emitting device 100A is greater than the wavelength of light emitted by the second light-emitting device 100B. The first distance D1 between the light extraction layers 170A corresponding to the first light-emitting device 100A is greater than the first distance D2 between the light extraction layers 170B corresponding to the second light-emitting device 100B.

[0182] The beneficial effects of the above-described method for preparing the display panel 200 are the same as those of the display panel 200 described in some of the above embodiments, and will not be repeated here.

[0183] In some examples, forming the light-emitting device 100 may include: sequentially laminating a first electrode 110, a light-emitting functional layer, a second electrode 120, and a light extraction layer 170 on a substrate 210 from bottom to top. The lamination process may be, for example, a vacuum evaporation process. The light-emitting functional layer includes a light-emitting layer 130.

[0184] In some examples, the light-emitting functional layer further includes one or more of the following: hole injection layer 151, hole transport layer 152, electron blocking layer 153, hole blocking layer 163, electron transport layer 162, and electron injection layer 161. Wherein the light-emitting functional layer includes hole injection layer 151, hole transport layer 152, electron blocking layer 153, hole blocking layer 163, electron transport layer 162, and electron injection layer 161, the hole injection layer 151, hole transport layer 152, electron blocking layer 153, light-emitting layer 130, hole blocking layer 163, electron transport layer 162, and electron injection layer 161 may be sequentially stacked in a direction away from the substrate 210.

[0185] In some examples, the hole injection layer 151 of the multiple light-emitting devices 100 can be a fully interconnected structure, that is, the hole injection layer 151 can be a common film layer shared by the multiple light-emitting devices 100. The hole transport layer 152, electron blocking layer 153, electron injection layer 161, electron transport layer 162 or hole blocking layer 163 can also be a common film layer shared by the multiple light-emitting devices 100, which will not be elaborated here.

[0186] In some embodiments, combined with Figure 5 Multiple light-emitting devices 100 (i.e., S2) are formed on the substrate 210, including S21.

[0187] S21: The first organic material and the second organic material are co-deposited to form the light extraction layer 170 of the light-emitting device 100. The coefficient of thermal expansion of the first organic material is greater than that of the second organic material.

[0188] In the process of forming the light extraction layer 170A of the first light-emitting device 100A, the evaporation rate of the first organic material and the evaporation rate of the second organic material have a first ratio. In the process of forming the light extraction layer 170B of the second light-emitting device 100B, the evaporation rate of the first organic material and the evaporation rate of the second organic material have a second ratio. The first ratio is greater than the second ratio.

[0189] In other words,

[0190] Where, ν 11 During the formation of the light extraction layer 170A of the first light-emitting device 100A, the evaporation rate of the first organic material, ν 12 The evaporation rate of the second organic material during the formation of the light extraction layer 170A of the first light-emitting device 100A. 21 During the formation of the light extraction layer 170B of the second light-emitting device 100B, the evaporation rate of the first organic material, ν 22 The evaporation rate of the second organic material during the formation of the light extraction layer 170B of the second light-emitting device 100B.

[0191] For example, based on the evaporation rate ratio, the volume percentage of the first organic material is in the range of 10% to 90%, such as 10%, 20%, 30%, 40%, 50%, 60%, 64%, 70%, 80%, or 90%. For example, based on the evaporation rate ratio, the volume percentage of the second organic material is in the range of 10% to 90%, such as 10%, 20%, 30%, 40%, 48%, 50%, 60%, 70%, 80%, or 90%. Wherein, the volume percentage of the first organic material based on the evaporation rate ratio refers to the volume percentage of the first organic material obtained based on the evaporation rate ratio, for example, the ratio of the evaporation rate of the first organic material to the sum of the evaporation rates of the first and second organic materials, i.e., ν1 / (ν 1+ ν2) 100%. Correspondingly, based on the evaporation rate ratio, the volume percentage of the second organic material refers to the volume percentage of the second organic material obtained based on the evaporation rate ratio, for example, the ratio of the evaporation rate of the second organic material to the sum of the evaporation rates of the first organic material and the second organic material, i.e., ν² / (ν...). 1+ ν2) 100%. Wherein, ν1 is the evaporation rate of the first organic material during the formation of a certain light extraction layer 170, and ν2 is the evaporation rate of the second organic material during the formation of a certain light extraction layer 170.

[0192] It should be understood that the volume percentage of the first organic material based on the evaporation rate ratio is related to the volume percentage of the first organic material in the light extraction layer 170, and the volume percentage of the second organic material based on the evaporation rate ratio is related to the volume percentage of the second organic material in the light extraction layer 170. When the first ratio is greater than the second ratio, the volume of the first organic material and the second organic material in the light extraction layer 170A of the first light-emitting device 100A is relatively large, and the volume of the first organic material and the second organic material in the light extraction layer 170B of the second light-emitting device 100B is relatively small.

[0193] In practical applications, the evaporation rate of the first organic material and the evaporation rate of the second organic material in the light extraction layer 170 of a certain light-emitting device 100 can be adjusted according to the difference in volume percentage between the first organic material and the second organic material in the light extraction layer 170 of the light-emitting device 100.

[0194] Understandably, when the light extraction layer 170 is formed by co-evaporation of the first organic material and the second organic material, since the coefficient of thermal expansion of the first organic material is greater than that of the second organic material, there will be a certain residual strain during the process of heating, expanding and cooling of the first organic material and the second organic material. This results in the formation of multiple protrusions 171 on the surface of the light extraction layer 170, which forms a certain micro-nano surface morphology. In this way, the multiple protrusions 171 can be used to improve the color shift problem, improve device efficiency, and enhance the process feasibility of forming multiple protrusions 171.

[0195] When the first ratio is greater than the second ratio, during the formation of the light extraction layer 170A of the first light-emitting device 100A, a larger volume ratio of the first organic material to the second organic material can be used to generate relatively large residual stress in the light extraction layer 170A of the first light-emitting device 100A, resulting in a light extraction layer 170A with a relatively large first distance D1 and a larger height H1 of the protrusion 171A. Conversely, during the formation of the light extraction layer 170B of the second light-emitting device 100B, a smaller volume ratio of the first organic material to the second organic material can be used to generate relatively small residual stress in the light extraction layer 170B of the second light-emitting device 100B, resulting in a light extraction portion 170B with a relatively small first distance D2 and a smaller height H2 of the protrusion 171B. This allows for a more consistent trend and magnitude of enhancement / weakening of different colors of light at the same viewing angle, alleviating color shift issues and reducing the degree of color change with viewing angle.

[0196] In some embodiments, such as Figure 5 As shown, the plurality of light-emitting devices 100 also includes a third light-emitting device 100C. During the formation of the light extraction layer 170C of the third light-emitting device 100C, the evaporation rate of the first organic material has a third ratio to the evaporation rate of the second organic material. This third ratio is less than the second ratio. By setting it up in this way, similar to the previous part, the first distance D3 corresponding to the light extraction layer 170C of the third light-emitting device 100C can be made smaller than the first distance D2 corresponding to the light extraction layer 170B of the second light-emitting device 100B, and the height H3 of the protrusion 171C of the light extraction layer 170C of the third light-emitting device 100C can be made smaller than the height H2 of the protrusion 171B of the light extraction layer 170B of the second light-emitting device 100B. This allows the trend and magnitude of the enhancement / weakening of different colored lights to be more consistent under the same viewing angle, which can alleviate the problem of color shift and reduce the degree of color change with viewing angle.

[0197] The technical solutions provided in this disclosure will be described exemplarily below through the following embodiments and comparative examples.

[0198] Example 1 like Figure 7 As shown, a dual-source evaporation method is used for co-evaporation to form a light extraction layer 170 above the second electrode 120 (cathode). The light extraction layer 170 is composed of a first organic material and a second organic material.

[0199] Example 1 includes the following three examples. In the different examples, the first organic material is of the same type, the second organic material is of the same type, but the volume ratio of the first organic material and the second organic material is different.

[0200] Example 1: Based on the evaporation rate ratio meter, the volume ratio of the first organic material in the material of the light extraction layer 170 is 20%, and the volume ratio of the second organic material in the material of the light extraction layer 170 is 80%. That is to say, the volume ratio of the first organic material and the second organic material is 1:4.

[0201] Example 2: Based on the evaporation rate ratio meter, the volume ratio of the first organic material in the material of the light extraction layer 170 is 50%, and the volume ratio of the second organic material in the material of the light extraction layer 170 is 50%. That is to say, the volume ratio of the first organic material and the second organic material is 1:1.

[0202] Example 3: Based on the evaporation rate ratio meter, the volume ratio of the first organic material in the material of the light extraction layer 170 is 80%, and the volume ratio of the second organic material in the material of the light extraction layer 170 is 20%. That is to say, the volume ratio of the first organic material to the second organic material is 4:1.

[0203] In this embodiment, the surface microstructure cross-sectional images of the light extraction layer 170 formed in Examples 1 to 3 were inspected, and the results are as follows: Figures 8A-8C As shown, the cross-sectional view of the surface microstructure of the light extraction layer 170 formed in Example 1 is as follows. Figure 8A As shown, a cross-sectional view of the surface microstructure of the light extraction layer 170 formed in Example 2 is shown below. Figure 8B As shown, a cross-sectional view of the surface microstructure of the light extraction layer 170 formed in Example 3 is shown below. Figure 8C As shown.

[0204] Example 2 Example 2 prepared a structure as shown in Figure 9 The display panel 200 shown is provided. A first light-emitting device 100A emits red light, a second light-emitting device 100B emits green light, and a third light-emitting device 100C emits blue light. The first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C together constitute the device in the display panel 200 that emits white light.

[0205] Combination Figure 5 The first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C have the same film layer configuration, all including a layer along the distance from the substrate 210 (see reference). Figure 2 The light extraction layer 170 is arranged sequentially in the following order: a first electrode 110 (anode), a hole injection layer 151, a hole transport layer 152, an electron blocking layer 153, a light-emitting layer 130, a hole blocking layer 163, an electron transport layer 162, an electron injection layer 161, a second electrode 120 (cathode), and a light extraction layer 170. The light extraction layer 170 is formed using a dual-source evaporation method, employing a triple mask for mixed evaporation to obtain the light extraction layers 170 for the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C, respectively. The volume ratio of the first organic material to the second organic material is achieved by adjusting the evaporation rates of the two evaporation sources.

[0206] Example 2 includes four examples, namely Example 1 to Example 4. The materials and thicknesses of the film layers in the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in Examples 1 to Example 4 are set as follows: (1) In the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in Examples 1 to Example 4, the thicknesses and materials of the other film layers, except for the light extraction layer 170 and the light-emitting layer 130, are the same. (2) In Examples 1 to 4, the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C have the same thickness of light-emitting layer 130, but the material is selected according to the color of light emission. That is, the light-emitting layer 130 of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C respectively includes organic materials for emitting red light, green light, and blue light. In Examples 1 to 4, the light-emitting layer 130 of the first light-emitting device 100A includes the same material, the light-emitting layer 130 of the second light-emitting device 100B includes the same material, and the light-emitting layer 130 of the third light-emitting device 100C includes the same material. (3) The material of the light extraction layer 170 is composed of a first organic material and a second organic material. However, in the light extraction layer 170 of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in Examples 1 to 4, the material types of the first organic material and the second organic material and their volume ratio are different. The specific arrangement is shown in Table 1.

[0207] Table 1

[0208] It should be noted that "HCPL-1:LCPL-1=4:1" in Table 1 means that the first organic material in the light extraction layer 170 is HCPL-1 and the second organic material is LCPL-1, and the volume ratio of the first organic material HCPL-1 to the second organic material LCPL-1 is 4:1. This volume ratio of the first organic material and the second organic material is calculated based on the volumes of the two organic materials in the formed light extraction layer 170. The meanings of other similar representations in Table 1 and Table 4 described below can be referred to this explanation, and will not be repeated here.

[0209] In Table 1, HCPL-1 represents a first organic material named 2-{4-[6-(dibenzo[1,2-b:1',2'-d]furan-1-yl)-4-(dibenzo[1,2-d:1',2'-b]furan-1-yl)-1,3,5-triazacyclohexamyl-2-yl]phenyl}benzo[d][1,3]oxazacyclopentane, with the structural formula shown in formula (I-1). This material can be obtained by synthesis, and the method can be found in relevant materials, such as Chinese patents with publication numbers CN106946859A and CN109206420A.

[0210] LCPL-1 represents a second organic material named 2-phenylisoindole-1,3-dione, with the structural formula shown in formula (II-1). LCPL-2 represents yet another second organic material named triphenylamine, with the structural formula shown in formula (II-2). Both materials are commercially available.

[0211] In Example 2, the coefficients of thermal expansion of the three materials mentioned above and the first organic material HCPL-2 used in the following comparative examples were measured using a thermomechanical analyzer. The results are shown in Table 2.

[0212] Table 2

[0213] In Example 2, the emission color and emission wavelength of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in the four examples were measured, and the results are shown in Table 1.

[0214] In Example 2, the current efficiency, CIE coordinates (including CIEx and CIEy) of the emitted light, the height of the protrusion 171, the first distance D corresponding to the light extraction layer 170, the BI of the third light-emitting device 100C, the color difference of the white light emitted by the display panel 200 at a 30° viewing angle (i.e., white light color difference @ 30°, in JNCD), and the color difference of the white light emitted by the display panel 200 at a 60° viewing angle (i.e., white light color difference @ 60°, in JNCD) were measured for the four examples. The results are shown in Table 3. BI is the ratio of current efficiency to CIEy (i.e., current efficiency / CIEy), used to evaluate the efficiency of the blue light-emitting device 100.

[0215] Table 3

[0216] It should be noted that “—” in Table 3 indicates that the BI of the light-emitting device 100 was not evaluated.

[0217] Comparative Example 1 Comparative Example 1 prepared structures such as Figure 9 The display panel 200 shown is provided. A first light-emitting device 100A emits red light, a second light-emitting device 100B emits green light, and a third light-emitting device 100C emits blue light. The first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C together constitute the device in the display panel 200 that emits white light.

[0218] In Comparative Example 1 and Example 2, the film layer configuration of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C, as well as the configuration of the materials and thicknesses of the other film layers except for the light extraction layer 170, are the same.

[0219] Comparative Example 1 includes four examples, namely Example 1 to Example 4. In the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C of Examples 1 to Example 4, the material of the light extraction layer 170 is different. The specific settings are shown in Table 4.

[0220] In Examples 1 and 2, the light extraction layer 170 is formed using a single-source evaporation method and the same mask is used. In Examples 3 and 4, the light extraction layer 170 is formed using a dual-source evaporation method, employing triple masks for mixed evaporation to obtain light extraction layers 170 for the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C, respectively. The volume ratio of the first organic material and the second organic material is achieved by adjusting the evaporation rates of the two evaporation sources.

[0221] Table 4

[0222] In Table 4, HCPL-2 represents another first organic material, named 2-{3,5-bis[4-(benzo[d][1,3]oxazacyclopentanyl-2-yl)phenyl]-1,3,5-triazacyclohex-1-yl}-9-phenylcarbazole, with the structural formula shown in formula (I-2). This material can be obtained by synthesis, and the method can be found in relevant published information, such as Chinese patents with publication numbers CN106946859A and CN109206420A.

[0223] In Comparative Example 1, the coefficient of thermal expansion of the first organic material HCPL-2 was measured using a thermomechanical analyzer, and the results are shown in Table 2.

[0224] In Comparative Example 1, the emission color and emission wavelength of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in the four examples were measured, and the results are shown in Table 4.

[0225] In Comparative Example 1, the current efficiency, CIE coordinates (including CIEx and CIEy) of the emitted light, the height of the protrusion 171, the first distance D corresponding to the light extraction layer 170, the BI of the third light-emitting device 100C, the color difference of the white light emitted by the display panel 200 at a 30° viewing angle (i.e., white light color difference @ 30°, in JNCD), and the color difference of the white light emitted by the display panel 200 at a 60° viewing angle (i.e., white light color difference @ 60°, in JNCD) were measured for the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C in the four examples, respectively. The results are shown in Table 5.

[0226] Table 5

[0227] As shown in Tables 3 and 5, compared with the display panel 200 in Comparative Example 1, the display panel 200 in Example 2, by adjusting the ratio of the first organic material and the second organic material in the light extraction layer 170, obtained light extraction layers 170 with different first distance D and heights of the protrusion 171. This significantly improves the current efficiency of the first light-emitting device 100A, the second light-emitting device 100B, and the third light-emitting device 100C, and significantly improves the perceptible color difference of the white light emitted by the white light device, with less angle dependence.

[0228] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A display panel, characterized in that, include: A substrate and a plurality of light-emitting devices disposed on the substrate; The light-emitting device includes: a first electrode, a light-emitting layer, a second electrode, and a light extraction layer stacked in a direction away from the substrate; the surface of the light extraction layer facing away from the second electrode has a plurality of protrusions. The vertices of two adjacent protrusions arranged along a first direction have a first distance along the first direction, which is perpendicular to the thickness direction of the substrate; The plurality of light-emitting devices include a first light-emitting device and a second light-emitting device. The wavelength of the light emitted by the first light-emitting device is greater than the wavelength of the light emitted by the second light-emitting device. The first distance corresponding to the light extraction layer of the first light-emitting device is greater than the first distance corresponding to the light extraction layer of the second light-emitting device.

2. The display panel according to claim 1, characterized in that, In the light extraction layer corresponding to a light-emitting device, the plurality of protrusions are arranged periodically.

3. The display panel according to claim 1, characterized in that, The height of the protrusion in the light extraction layer of the first light-emitting device is greater than the height of the protrusion in the light extraction layer of the second light-emitting device.

4. The display panel according to claim 1, characterized in that, The bottom surface of the protrusion is a circular or near-circular bottom surface; and / or... The first distance is in the range of 500nm to 900nm; and / or, The height of the protrusion is in the range of 50nm to 100nm.

5. The display panel according to any one of claims 1 to 4, characterized in that, The material of the light extraction layer includes a first organic material and a second organic material, wherein the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. The volume ratio of the first organic material to the second organic material in the light extraction layer of the first light-emitting device is greater than the volume ratio of the first organic material to the second organic material in the light extraction layer of the second light-emitting device.

6. The display panel according to claim 5, characterized in that, The difference in the coefficients of thermal expansion between the first organic material and the second organic material is greater than or equal to a set threshold; the set threshold is greater than or equal to 50 × 10⁻⁶. -6 K - ¹.

7. The display panel according to claim 5, characterized in that, In the material of the light extraction layer, the volume ratio of the first organic material to the second organic material is in the range of 1:9 to 9:

1.

8. The display panel according to claim 5, characterized in that, The coefficient of thermal expansion of the first organic material is 12 × 10⁻⁶. -6 K - ¹~100×10 -6 K - Within the range of ¹; and / or, The coefficient of thermal expansion of the second organic material is 12 × 10⁻⁶. -6 K - ¹~100×10 -6 K - Within the range of ¹.

9. The display panel according to claim 5, characterized in that, The first organic material includes bisspirofluorene materials; and / or, The second organic material includes triphenylamine materials, 1,3,5 Triphenylbenzene materials, N Methylphthalimide materials and 2 Phenyl Isoindole 1,3 At least one of the diketone materials.

10. The display panel according to claim 5, characterized in that, The first organic material includes at least one of the structures shown in the following structural formulas (I-1) to (I-3); 、 、 。 11. The display panel according to claim 5, characterized in that, The second organic material includes at least one of the structures shown in the following structural formulas (II-1) to (II-3); 、 、 。 12. The display panel according to any one of claims 1 to 4, characterized in that, The plurality of light-emitting devices further includes a third light-emitting device, wherein the wavelength of the light emitted by the third light-emitting device is less than the wavelength of the light emitted by the second light-emitting device; and the first distance corresponding to the light extraction layer of the third light-emitting device is less than the first distance corresponding to the light extraction layer of the second light-emitting device.

13. The display panel according to claim 12, characterized in that, The material of the light extraction layer includes a first organic material and a second organic material, wherein the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. The volume ratio of the first organic material to the second organic material in the light extraction layer of the third light-emitting device is less than the volume ratio of the first organic material to the second organic material in the light extraction layer of the second light-emitting device.

14. The display panel according to any one of claims 1 to 4, characterized in that, The thickness of the light extraction layer is in the range of 10nm to 1000nm.

15. The display panel according to any one of claims 1 to 4, characterized in that, At a 30° viewing angle, the color difference of the white light emitted by the display panel is within the range of 1.0 JNCD to 1.6 JNCD; and / or, At a 60° viewing angle, the color difference of the white light emitted by the display panel is in the range of 1.3 JNCD to 2.4 JNCD.

16. A display device, characterized in that, include: The display panel as described in any one of claims 1 to 15; The driver chip is coupled to the display panel.

17. A method for manufacturing a display panel, characterized in that, include: Provide substrate; Multiple light-emitting devices are formed on the substrate; The light-emitting device includes: a first electrode, a light-emitting layer, a second electrode, and a light extraction layer stacked along a direction away from the substrate; a plurality of protrusions are formed on the surface of the light extraction layer facing away from the second electrode; a first distance is formed between the vertices of two adjacent protrusions along a first direction, the first direction being perpendicular to the thickness direction of the substrate; the plurality of light-emitting devices includes a first light-emitting device and a second light-emitting device, the wavelength of light emitted by the first light-emitting device is greater than the wavelength of light emitted by the second light-emitting device, and the first distance corresponding to the light extraction layer of the first light-emitting device is greater than the first distance corresponding to the light extraction layer of the second light-emitting device.

18. The method for manufacturing a display panel according to claim 17, characterized in that, The process of forming multiple light-emitting devices on the substrate includes: co-depositing a first organic material and a second organic material to form a light extraction layer for the light-emitting devices; wherein the coefficient of thermal expansion of the first organic material is greater than that of the second organic material. In the process of forming the light extraction layer of the first light-emitting device, the evaporation rate of the first organic material and the evaporation rate of the second organic material have a first ratio; in the process of forming the light extraction layer of the second light-emitting device, the evaporation rate of the first organic material and the evaporation rate of the second organic material have a second ratio; the first ratio is greater than the second ratio.

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