Display panel and display device

Abstract

Provided is a display panel comprising a plurality of sub-pixels (3), each sub-pixel (3) comprising: a backplane (31); and a first electrode (32) located on the back plate (31), the first electrode (32) comprising a central region (3211) and an edge region (3212) surrounding the central region (3211), the reflectivity of the central region (3211) of the first electrode (32) being different from the reflectivity of the edge region (3212) of the first electrode (32). The invention further provides a display device.

Description

Display panel and display device Technical Field

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

[0002] Currently, OLED (Organic Light-Emitting Diode) display panels are increasingly being used. In an OLED display panel, the light-emitting devices typically include a plurality of OLED light-emitting devices distributed in an array, each of which can emit light independently to display an image.

[0003] However, due to manufacturing process reasons, the performance of OLED display panels still needs to be improved.

[0004] Summary of the Invention

[0005] Embodiments of the present disclosure provide a display substrate and a display device.

[0006] According to one aspect of the present disclosure, a display panel is provided, including a plurality of sub-pixels, each sub-pixel may include: a backplane; and a first electrode located on the backplane, the first electrode including a central area and an edge area surrounding the central area, wherein the reflectivity of the central area of ​​the first electrode may be different from the reflectivity of the edge area of ​​the first electrode.

[0007] In an exemplary embodiment of the present disclosure, each sub-pixel may further include: a pixel definition layer located on the backplane, the pixel definition layer having an opening exposing a portion of the first electrode, so that the first electrode has a first portion exposed by the opening and a second portion covered by the pixel definition layer.

[0008] In an exemplary embodiment of the present disclosure, the central area of ​​the first electrode may include the central area of ​​the first part, and the edge area of ​​the first electrode may include the edge area of ​​the first part, and wherein the reflectivity of the central area of ​​the first part may be less than the reflectivity of the edge area of ​​the first part.

[0009] In an exemplary embodiment of the present disclosure, the central area of ​​the first electrode includes the first portion, the edge area of ​​the first electrode includes the second portion, and the reflectivity of the second portion of the first electrode is lower than the reflectivity of the first portion of the first electrode.

[0010] In an exemplary embodiment of the present disclosure, the first electrode may include: a first conductive layer located on the backplane; a second conductive layer located on a side of the first conductive layer away from the backplane; and a third conductive layer located on a side of the second conductive layer away from the backplane, wherein the reflectivity of the first conductive layer may be greater than the reflectivity of the second conductive layer and the third conductive layer.

[0011] In an exemplary embodiment of the present disclosure, the first conductive layer and the third conductive layer may be located at the first portion and the second portion of the first electrode, and the second conductive layer may be located at a central area of ​​the first portion and the second portion.

[0012] In an exemplary embodiment of the present disclosure, the first conductive layer may include a stacked structure of at least one of a metal or an alloy and a metal nitride, the second conductive layer may include a metal nitride, and the third conductive layer may include a transparent metal oxide.

[0013] In an exemplary embodiment of the present disclosure, the first conductive layer may include a stacked structure of a titanium layer, a titanium nitride layer, and an aluminum layer, the second conductive layer may include a titanium nitride layer, and the third conductive layer may include an indium tin oxide layer.

[0014] In an exemplary embodiment of the present disclosure, the aluminum layer may include an aluminum alloy layer.

[0015] In an exemplary embodiment of the present disclosure, the material of the aluminum alloy in the central area of ​​the first part may be different from the material in the edge area of ​​the first part, so that the reflectivity of the aluminum alloy in the edge area of ​​the first part is greater than the reflectivity of the aluminum alloy in the central area of ​​the first part.

[0016] In an exemplary embodiment of the present disclosure, a thickness of the first conductive layer in a central region of the first portion may be smaller than a thickness of the first conductive layer in an edge region of the first portion.

[0017] In an exemplary embodiment of the present disclosure, a thickness of the aluminum layer in a central region of the first portion may be smaller than a thickness of the aluminum layer in an edge region of the first portion.

[0018] In an exemplary embodiment of the present disclosure, the first electrode may further include an anti-reflection layer or a light absorption layer located in the second portion and between the first conductive layer and the second conductive layer.

[0019] In an exemplary embodiment of the present disclosure, the surface of the first conductive layer away from the back plate includes a first sub-surface located in the first part and a second sub-surface located in the second part, wherein the roughness of the second sub-surface is greater than the roughness of the first sub-surface.

[0020] In another exemplary embodiment of the present disclosure, the surface of the first conductive layer away from the back plate includes a first sub-surface located in the first part and a second sub-surface located in the second part, wherein the first sub-surface includes a central part located in the central area of ​​the first part and an edge part located in the edge area of ​​the first part, and wherein the roughness of the edge part of the first sub-surface is less than the roughness of the central part of the first sub-surface.

[0021] In an exemplary embodiment of the present disclosure, each sub-pixel may further include a light-emitting functional layer located on a side of the pixel definition layer away from the backplane; and a second electrode located on a side of the light-emitting functional layer away from the backplane.

[0022] In an exemplary embodiment of the present disclosure, the radius R of the central area of ​​the first portion satisfies:

[0023] R=width of the opening of the pixel definition layer-2*thickness of the light-emitting functional layer*tanθ,

[0024] Wherein, θ is the incident angle of light emitted by the light-emitting functional layer on the first electrode.

[0025] In an exemplary embodiment of the present disclosure, the second electrode may include a transparent layer and a transflective layer.

[0026] In an exemplary embodiment of the present disclosure, the transparent layer may include a transparent metal oxide, and the transflective layer may include a metal or an alloy.

[0027] In an exemplary embodiment of the present disclosure, the thickness of the alloy layer may be 10 Å-100 Å.

[0028] In an exemplary embodiment of the present disclosure, the sub-pixels include a red sub-pixel, a green sub-pixel, and a blue sub-pixel, wherein the reflectivity of the edge area of ​​the first part of the first electrode of the red sub-pixel is less than the reflectivity of the edge area of ​​the first part of the first electrode of the green sub-pixel and the reflectivity of the edge area of ​​the first part of the first electrode of the blue sub-pixel.

[0029] In another aspect of the present disclosure, a display device is provided, including the display panel described in any one of the embodiments of the present disclosure involving a display panel.

[0030] Further aspects and scope of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for illustrative purposes and are not intended to limit the scope of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. In the drawings:

[0032] FIG1 schematically shows a cross-sectional view of an OLED display panel in the related art;

[0033] FIG2 schematically illustrates the microcavity effect for a single sub-pixel in an OLED display panel;

[0034] FIG3 schematically shows a cross-sectional view of a display panel in one or more embodiments of the present disclosure;

[0035] FIG4 schematically illustrates a cross-sectional view of a first electrode in one or more embodiments of the present disclosure;

[0036] FIG5 schematically illustrates the partitioning of the first electrode in one or more embodiments of the present disclosure;

[0037] FIG6 schematically shows a plan view of a first electrode in one or more embodiments of the present disclosure;

[0038] FIG7 schematically illustrates a plan view of a stack of a first electrode and a pixel definition layer in one or more embodiments of the present disclosure;

[0039] FIG8 schematically illustrates a light-emitting functional layer having a stacked structure in one or more embodiments of the present disclosure;

[0040] FIG9 schematically shows a first electrode in another embodiment of the present disclosure; and

[0041] FIG10 schematically illustrates a display device according to one or more embodiments of the present disclosure.

[0042] Corresponding reference numerals indicate corresponding parts or features throughout the several views of the drawings. DETAILED DESCRIPTION

[0043] Various embodiments will now be described in detail with reference to the accompanying drawings, which are provided as exemplary examples of the present disclosure to enable those skilled in the art to implement the present disclosure.

[0044] It is worth noting that the following figures and examples are not meant to limit the scope of the present disclosure. Where certain elements of the present disclosure can be implemented in part or in whole using known components, only those portions of such known components necessary for understanding the present disclosure will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the present disclosure. Furthermore, the various embodiments encompass, by way of illustration, all presently and future known equivalents to the components referred to herein.

[0045] As used herein, the terms "have," "comprise," and "contain," and grammatical variations thereof, are used in a non-exclusive manner. Thus, the expression "A has B," as well as the expressions "A includes B," or "A comprises B," may refer to the fact that A includes one or more other components and / or members in addition to B, as well as the fact that no other components, members, or elements are present in A in addition to B. The terms "a," "an," "the," "said," and "at least one" are used to indicate the presence of one or more elements / components / etc.

[0046] However, as used herein, the term "located on" does not refer to a specific geometric orientation of the display panel or the final stack in the display device relative to the direction of gravity. Instead, it refers to the manner in which the stack is manufactured, and after manufacturing, the stack can generally be placed in any geometric orientation, such as upside down. The terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or order of formation.

[0047] Among OLED display technologies, silicon-based OLEDs offer the advantages of small size and high resolution. Silicon-based OLEDs utilize mature integrated circuit (CMOS) processes, enabling active pixel addressing and supporting various circuits such as TCON and OCP, contributing to lightweight design. Silicon-based OLEDs are widely used in near-eye displays, virtual reality, and augmented reality, particularly in AR / VR head-mounted displays.

[0048] Figure 1 schematically shows a cross-sectional view of an OLED display panel in the related art. As shown in Figure 1, the OLED display panel may include a driving backplane 11, multiple first electrodes 12, a pixel definition layer 13, a light-emitting functional layer 14, a second electrode 15, and a color filter layer 16. The first electrodes 16 are arranged in an array on the driving backplane 11; the pixel definition layer 13 is provided on the surface of the driving backplane 11 on which the first electrodes 12 are provided, and has an opening that exposes at least a portion of each first electrode 12; the light-emitting functional layer 14 covers the surface of the pixel definition layer 13 and the first electrodes 12 facing away from the driving backplane 11, and the second electrode 15 covers the surface of the light-emitting functional layer 14 facing away from the driving backplane 11, thereby defining multiple light-emitting devices through the pixel definition layer 13. Driven by a driving signal, holes injected by the first electrode 12 and electrons injected by the second electrode 15 enter the light-emitting functional layer 14 and form excitons, which undergo radiative transitions and emit photons, thereby forming electroluminescence. The color filter layer 16 is disposed on a side of the second electrode 15 away from the driving backplane 11 and has a plurality of filter regions corresponding to respective light emitting devices. Each filter region and its corresponding light emitting device can serve as a sub-pixel.

[0049] With the development and application of OLED display technology, particularly micro-OLED display technology, the demand for brightness in OLED products is increasing. To improve the brightness of each OLED light-emitting device, the various OLED components are typically configured based on the microcavity principle. The first electrode 12, the light-emitting functional layer 14, and the second electrode 15 can form a microcavity structure. By properly setting the thickness between the first electrode 12 and the second electrode 15, a strong microcavity can be formed between the first electrode 12 and the second electrode 15, thereby improving the luminous efficiency of the OLED display device.

[0050] In satisfaction A strong microcavity effect can be achieved when d is the distance between the first electrode 12 and the second electrode 15, n is the effective refractive index of the medium between the first electrode 12 and the second electrode 15, N is an integer greater than or equal to 0, and λ is the central wavelength of the emitted light. According to the above formula, the strong microcavity effect mainly depends on the distance d between the first electrode 12 and the second electrode 15 and the central wavelength λ of the emitted light.

[0051] However, due to the manufacturing process or other factors, at least one of the first electrode 12 and the second electrode 15, particularly the second electrode 15, which typically serves as the cathode, may experience morphological changes near the edge of each subpixel. As shown in FIG1 , the second electrode 15 may have a step difference A at the edge of each subpixel. This results in the distance between the first electrode 12 and the second electrode 15 in the central region of each subpixel being inconsistent with the distance between the first electrode 12 and the second electrode 15 in the edge region of the corresponding subpixel. On the other hand, due to the potential for crosstalk between adjacent subpixels, the central wavelength of the edge region of the subpixel may differ from the central wavelength of the central region. Therefore, while the central region of each subpixel meets the strong microcavity condition, the edge region no longer meets the strong microcavity condition because the distance between the first electrode 12 and the second electrode 15 in the edge region of each subpixel and the central wavelength of the emitted light in the edge region may change. Therefore, the edge region of the subpixel becomes a weak microcavity region. FIG2 schematically illustrates the microcavity effect for a single subpixel in an OLED display panel. As shown in FIG2 , the central region 21 of subpixel 2 is a strong microcavity region, while the edge region 22 of the subpixel is a weak microcavity region. This results in a lower light extraction rate in the edge region 22 of the sub-pixel.

[0052] Furthermore, due to variations in electrode topography, the electric field between the first electrode 12 and the second electrode 15 in the sub-pixel edge region may differ from the electric field between the first electrode 12 and the second electrode 15 in the central region. This change in the electric field also affects the light extraction rate at the edge of each sub-pixel. The change in the electric field caused by the change in electrode topography at the sub-pixel edge can also cause some light to change direction, emitting from adjacent sub-pixels or the non-luminescent region between two adjacent sub-pixels, which can cause crosstalk.

[0053] Furthermore, as shown in FIG1 , since the first electrode 12 generally extends into the non-effective light-emitting region of the sub-pixel (corresponding to the region covered by the pixel definition layer) and the second electrode 15 is a continuous film layer, an electric field also exists in the non-effective light-emitting region of the sub-pixel, causing the light-emitting functional layer 14 in this non-effective light-emitting region to also emit a certain amount of light. Light emitted from this non-effective light-emitting region may partially exit from the microcavity structure formed by the first electrode 12 and the second electrode 15, which is generally undesirable.

[0054] Embodiments of the present disclosure provide a display panel and a display device, in which the first electrode has different reflectivities in different areas corresponding to each pixel, which can not only improve the light uniformity of the effective light-emitting area of ​​the pixel (corresponding to the opening area of ​​the pixel definition layer), but also reduce the light emitted from the non-effective light-emitting area between the pixels.

[0055] In some embodiments of the present disclosure, a display panel is disclosed, comprising a plurality of sub-pixels, each of which may include a backplane and a first electrode located on the backplane, the first electrode including a central region and an edge region surrounding the central region. The reflectivity of the central region of the first electrode may be different from the reflectivity of the edge region of the first electrode. By setting different reflectivities for different regions of the first electrode, not only can the uniformity of light emission from the effective light-emitting region of the pixel be improved, but also the light emitted from the non-effective light-emitting region between the pixels can be reduced.

[0056] FIG3 schematically illustrates a cross-sectional view of a display panel in one or more embodiments of the present disclosure. As shown in FIG3 , the display panel may include a plurality of sub-pixels 3, each of which may include a backplane 31, a first electrode 32 located on the backplane 31, a pixel definition layer 33 located on a side of the first electrode 32 away from the backplane 31, a light-emitting functional layer 34 located on a side of the pixel definition layer 33 away from the backplane 31, and a second electrode 35 located on a side of the light-emitting functional layer 34 away from the pixel definition layer 33. In some embodiments of the present disclosure, each first electrode 32 may be dedicated to a corresponding sub-pixel 3, while the pixel definition layer 33, the light-emitting functional layer 34, and the second electrode 35 may be continuous for multiple sub-pixels 3. That is, multiple sub-pixels 3 may share the pixel definition layer 33, the light-emitting functional layer 34, and the second electrode 35.

[0057] The various components of the display panel provided by the embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0058] In some embodiments of the present disclosure, the backplane 31 may be a silicon-based backplane, which may include a substrate and a plurality of drive transistors disposed on the substrate. The substrate may include a semiconductor material such as single-crystal silicon or polycrystalline silicon. The drive transistors may be used to drive each sub-pixel to emit light to display an image. The drive transistors may include an active region, an insulating layer, a gate, and source / drain electrodes.

[0059] In some embodiments of the present disclosure, a plurality of first electrodes 32 may be arrayed on the backplane to correspond one-to-one to a plurality of sub-pixels. FIG4 schematically shows a cross-sectional view of a first electrode in one or more embodiments of the present disclosure, and FIG5 schematically shows a partition of the first electrode in one or more embodiments of the present disclosure. For ease of explanation, a portion of the pixel definition layer 33 is also shown in FIG4 . As shown in FIG4 and FIG5 , each first electrode 32 may have a second portion 322 covered by the pixel definition layer 33 located thereon and a first portion 321 exposed by the opening 331 of the pixel definition layer 33. The first portion 321 may correspond to the effective light-emitting area of ​​the sub-pixel 3, and the first portion 321 may include a central area 3211 corresponding to the central area of ​​the effective light-emitting area and an edge area 3212 corresponding to the edge area of ​​the effective light-emitting area. The second portion 322 may correspond to the non-effective light-emitting area of ​​the sub-pixel, that is, the area covered by the pixel definition layer.

[0060] FIG6 schematically illustrates a plan view of a first electrode in one or more embodiments of the present disclosure. As shown in FIG6 , in some embodiments of the present disclosure, the first electrode 32 may be hexagonal. In other embodiments, the first electrode 32 may also be other polygonal shapes, such as a quadrilateral. In still other embodiments, the first electrode 32 may also be an irregular shape.

[0061] FIG7 schematically illustrates a plan view of a stack of a first electrode and a pixel definition layer in one or more embodiments of the present disclosure. As shown in FIG7 , the pixel definition layer 33 is positioned on the first electrode 32 and covers the second portion 322 of the first electrode 32, while exposing the first portion 321 of the first electrode 32 through an opening 331. In some embodiments, the opening 331 of the pixel definition layer 33 may have the same shape as the first electrode, but the size of the opening of the pixel definition layer 33 may be smaller than the size of the first electrode 32 so that the opening 331 of the pixel definition layer 33 does not fully expose the first electrode 32. In other embodiments, the shape of the opening 331 of the pixel definition layer 33 may be different from the shape of the first electrode 32.

[0062] In some embodiments of the present disclosure, the central region of the first electrode 31 may include a central region 3211 of the first portion 321 exposed by the opening of the pixel definition layer, and the edge region of the first electrode 32 may include an edge region 3212 of the first portion 321 exposed by the pixel definition layer 33. In some embodiments, the reflectivity of the central region 3211 of the first portion 321 may be lower than the reflectivity of the edge region 3212 of the first portion 321.

[0063] This configuration increases the reflectivity of the edge region 3212 of the first portion 321 relative to the center region 3211 of the first portion 321, allowing more light to be reflected from the edge region 3212 of the first portion 321 toward the light-emitting side of the display panel. This improves the light-extraction efficiency of the edge region of the effective light-emitting area of ​​the sub-pixel 3. Therefore, by increasing the reflectivity of the edge region 3212 of the first portion 321, the uniformity of light emission from the sub-pixel 3 of the display panel can be improved, thereby enhancing the display quality.

[0064] In some embodiments of the present disclosure, the thickness of the edge region 3212 of the first portion 321 may be less than the thickness of the central region 3211 of the first portion 321. Generally, reducing the thickness of the edge region 3212 of the first portion 321 compared to the central region 3211 of the first portion 321 may increase the reflectivity of the edge region 3212 of the first portion 321.

[0065] In some embodiments of the present disclosure, in order to ensure that the first electrode 32 has good electrical conductivity, good chemical and morphological stability, and a high work function, the first electrode 32 generally includes a multilayer structure. In an exemplary embodiment, the first electrode 32 may include a first conductive layer 323 located on the backplate 31, a second conductive layer 324 located on a side of the first conductive layer 323 away from the backplate 31, and a third conductive layer 325 located on a side of the second conductive layer 324 away from the backplate 31. In some embodiments, as shown in FIG. 4 , the first conductive layer 323 and the third conductive layer 325 may be located in the first portion 321 and the second portion 322 of the first electrode 32, and the second conductive layer 324 may be located only in the central region 3211 of the first portion 321 and the second portion 322. That is, for a single sub-pixel 3, the first conductive layer 323 and the third conductive layer 325 are both continuous, while the second conductive layer 324 is disconnected in the edge region 3212 of the first portion 321, such that the second conductive layer 324 is located only in the central region 3211 and the second portion 322 of the first portion 321, and is absent in the edge region 3212 of the first portion 321. Typically, the reflectivity of the first conductive layer can be greater than that of the second and third conductive layers. By not providing the second conductive layer in the edge region of the first portion of the first electrode, the absorption of light by the second conductive layer in the edge region of the first portion can be reduced, thereby allowing more light to be incident on and reflected by the first conductive layer. Therefore, the reflection of light by the first electrode, specifically the first conductive layer of the first electrode, in the edge region of the first portion can be increased, thereby increasing the brightness of the edge region of the effective opening area of ​​the sub-pixel.

[0066] In some embodiments of the present disclosure, the third conductive layer 325 may fill the gap formed by the disconnection of the second conductive layer 324 at the edge region 3212 of the first portion 321. In some embodiments, the thickness of the third conductive layer 325 at the gap is equal to the sum of the thickness of the second conductive layer 324 and the thickness of the third conductive layer 325 at other locations, so that the surface of the third conductive layer 325 facing away from the backplate 31 is flat. In other embodiments, the thickness of the third conductive layer 325 at the gap is less than the sum of the thickness of the second conductive layer 324 and the thickness of the third conductive layer 325 at other locations, so that the surface of the third conductive layer 325 facing away from the backplate 31 is concave toward the gap.

[0067] In an exemplary embodiment, the first conductive layer 323 may include a metal layer, for example, a single-element metal layer with a high work function, such as aluminum, silver, titanium, or barium. In another exemplary embodiment, the first conductive layer 323 may include a stacked structure of a metal and a metal nitride, for example, a stacked structure of a titanium layer, a titanium nitride layer, and an aluminum layer, i.e., Ti / TiN / Al. As an example, in the stacked structure, the thicknesses of the titanium layer, the titanium nitride layer, and the aluminum layer may be 200 Å, 100 Å, and 700 Å, respectively. In some embodiments, the aluminum layer may include an aluminum alloy layer, for example, an aluminum-copper alloy. The first conductive layer 323 may include a metal layer or a stacked structure including multiple layers of metal or metal alloys, so that the first conductive layer 323 has a higher reflectivity. In some embodiments of the present disclosure, the first conductive layer 323 may serve as the main reflective layer of the first electrode 32.

[0068] In an exemplary embodiment, the second conductive layer 324 may include a metal nitride, such as a titanium nitride layer. Using titanium nitride as the second conductive layer 324 of the first electrode 32 can improve the work function and facilitate hole injection. As an example, the thickness of the second conductive layer 323 can be 15 Å.

[0069] The third conductive layer 325 may include a transparent metal oxide, such as ITO, ZnO, or AZO (Al:ZnO). In some embodiments, the third conductive layer 325 may cover the second conductive layer 324 and the first conductive layer 323 and extend onto the backplane 31 at a certain slope to cover the first conductive layer 323 and the second conductive layer 324 together with the backplane 31. In some embodiments, the third conductive layer 325 may also include a first transparent metal oxide layer and a second transparent metal oxide layer. In an exemplary embodiment, the thickness of the second transparent metal oxide layer may be approximately three times the thickness of the first transparent metal oxide layer. As an example, the thickness of the first transparent metal oxide layer may be 50 Å, and the thickness of the second transparent metal oxide layer may be 150 Å.

[0070] In some embodiments of the present disclosure, the material of the first conductive layer 323 may be different in the central region 3211 of the first portion 321 and the edge region 3212 of the first portion 321, so that the reflectivity of the first conductive layer 323 in the edge region 3212 of the first portion 321 is greater than the reflectivity of the central region 3211 of the first portion 321. In an exemplary embodiment, the first conductive layer 323 is made of an aluminum alloy material different from that in the central region 3211 of the first portion 321. As an example, the aluminum alloy layer of the first conductive layer 323 in the central region 3211 of the first portion 321 may be made of an aluminum-copper alloy, while the aluminum alloy layer of the first conductive layer 323 in the edge region 3212 of the second portion 321 may be made of an aluminum-silver alloy.

[0071] In a further embodiment, to further improve the reflectivity of the edge region 3212 of the first portion 321 of the first electrode 31, the thickness of the first conductive layer 323 in the central region 3211 of the first portion 321 can be made thinner than the thickness of the first conductive layer 323 in the edge region 3212 of the first portion 321. In an embodiment where the first conductive layer 323 includes a stacked structure of a titanium layer, a titanium nitride layer, and an aluminum layer, i.e., Ti / TiN / Al, the thickness of the aluminum layer in the central region 3211 of the first portion 321 can be made thinner than the thickness of the aluminum layer in the edge region 3212 of the first portion 321. As an example, in the central region 3211 of the first portion 321, the thicknesses of the titanium layer, the titanium nitride layer, and the aluminum layer can be 200 Å, 100 Å, and 700 Å, respectively, while in the edge region 3212 of the first portion 321, the thicknesses of the titanium layer, the titanium nitride layer, and the aluminum layer can be 200 Å, 100 Å, and 500 Å, respectively. Since for the reflective layer, the greater the thickness, the greater the reflectivity, therefore, increasing the thickness of the first conductive layer 323 in the edge area 3212 of the first part 321 can increase the reflectivity of the edge area 3212 of the first part 321, thereby improving the light output rate of the edge area of ​​the effective opening area of ​​the sub-pixel 3 to ensure the uniformity of light output of the entire sub-pixel 3.

[0072] In an embodiment of the present disclosure in which the reflectivity of the first conductive layer of the first electrode 32 is greater than the reflectivity of the second conductive layer and the third conductive layer, the surface of the first conductive layer away from the backplane may include a first sub-surface located in the first portion and a second sub-surface located in the second portion, and the first sub-surface may include a central portion located in the central area of ​​the first portion and an edge portion located in the edge area of ​​the first portion. In some embodiments of the present disclosure, the roughness of the edge portion of the first sub-surface of the first conductive layer 323 may be made smaller than the roughness of the central portion of the first sub-surface. Generally, the greater the roughness, the higher the reflectivity. Therefore, by making the roughness of the edge portion of the first sub-surface smaller than the roughness of the central portion of the first sub-surface, the reflectivity of the edge portion of the first surface may be made greater than the reflectivity of the central portion of the first sub-surface, so that the reflectivity of the central area 3211 of the first portion 321 is smaller than the reflectivity of the edge area 3212 of the first portion 321.

[0073] As an example, in the process of forming the first conductive layer 323 by a dry etching process, the surface of the edge area 3212 of the first part 321 of the first conductive layer 323 (i.e., the edge part of the first sub-surface) can be smoothed to increase the reflectivity of the first conductive layer 323 in the edge area 3212 of the first part 321.

[0074] As described above, each sub-pixel 3 may further include a light-emitting functional layer 34 located on a side of the pixel definition layer 33 away from the back plate 31 .

[0075] In some embodiments, the light emitting functional layer 34 may include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

[0076] In other embodiments, to improve brightness and extend service life, a stacked structure of multiple light-emitting functional sublayers is typically employed to achieve color display by combining white light with a color filter layer. The light-emitting functional layer 34 may include multiple light-emitting functional sublayers arranged in a stacked structure. Each light-emitting functional sublayer may include a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. A charge generation layer is provided between two adjacent light-emitting functional sublayers. Through the charge generation layer, multiple light-emitting functional sublayers can be connected in series to form a tandem OLED light-emitting device. Figure 8 schematically illustrates a light-emitting functional layer having a stacked structure in one or more embodiments of the present disclosure. As shown in Figure 8, the light-emitting functional layer may include a first light-emitting functional sublayer 41, a second light-emitting functional sublayer 42, and a third light-emitting functional sublayer 43 connected in series via a charge generation layer 44. The first light-emitting functional sublayer 41 emits red light, the second light-emitting functional sublayer 42 emits green light, and the third light-emitting functional sublayer 43 emits blue light. To enable this tandem OLED light-emitting device to emit colored light, a color filter layer may be provided on the light-emitting side, thereby pixelating the tandem OLED light-emitting device into red, green, and blue subpixels.

[0077] As mentioned above, in tandem OLED light-emitting devices, a charge generation layer is typically placed between different color light-emitting functional layers to provide carriers for the light-emitting functional layers on either side. However, because the charge generation layer is typically made of highly conductive materials with high carrier mobility, it can easily lead to leakage between adjacent pixels. This can cause light to be emitted from the non-luminous areas between adjacent pixels, resulting in crosstalk between pixels.

[0078] In addition, as mentioned above, the electric field in the edge area of ​​the sub-pixel 3 may change due to reasons such as the manufacturing process. These factors will cause light to be generated in the non-luminous area between adjacent sub-pixels 3. If light is reflected back and forth between the first electrode 32 and the second electrode 35 in the non-luminous area, some light will be emitted from the non-luminous area between adjacent sub-pixels 3 or reflected to the adjacent sub-pixel, thereby causing crosstalk, which is usually undesirable. Therefore, it is desirable to reduce the reflectivity of the second portion 322 of the first electrode 32 covered by the pixel definition layer to reduce the light emitted from the non-luminous area between adjacent sub-pixels 3 or the light emitted to the adjacent sub-pixel.

[0079] Therefore, as an alternative or supplement to some of the above embodiments, the edge region of the first electrode 32 further includes a second portion 322 of the first electrode 32 covered by the pixel definition layer 33, and the reflectivity of the second portion 322 is lower than the reflectivity of the first portion 321, in particular, lower than the reflectivity of the central region 3211 of the first portion 321. By reducing the reflectivity of the second portion 322 of the first electrode 32 as compared to the first portion 321 of the first electrode 32, it is possible to reduce unwanted light emitted from the non-luminous region between the sub-pixels 3 or reflected to the adjacent sub-pixels 3.

[0080] In some embodiments, to reduce the reflectivity of the second portion 322 of the first electrode 32, an anti-reflection layer or a light-absorbing layer may be provided on the second portion 322 of the first electrode 32. FIG9 schematically illustrates a first electrode according to another embodiment of the present disclosure. As shown in FIG9, the anti-reflection layer and the light-absorbing layer 38 may be provided between the first conductive layer 323 and the second conductive layer 324. The anti-reflection layer or the light-absorbing layer 38 can reduce reflection of light from the second portion 322 of the first electrode 32, thereby reducing light emitted from the region of the sub-pixel 3 corresponding to the second portion 322.

[0081] In other embodiments, to reduce the reflectivity of the second portion 322 of the first electrode 32, the first sub-surface located in the first portion 321 and the second sub-surface located in the second portion 322 of the first conductive layer 323, which is the surface away from the back plate 31, may have different roughnesses. Specifically, the roughness of the second sub-surface may be greater than that of the first sub-surface. Therefore, the reflectivity of the second sub-surface may be lower than that of the first sub-surface, thereby making the reflectivity of the second portion 322 of the first electrode 32 lower than that of the first portion 321.

[0082] As an example, during the process of forming the first conductive layer 323 by a dry etching process, the second sub-surface of the first conductive layer 323 located in the second portion 322 can be roughened. Generally, for the same material, the rougher the surface, the lower the reflectivity. Therefore, roughening the second sub-surface of the first conductive layer 323 located in the second portion 322 can make the first conductive layer 323 have a lower reflectivity in the second portion 322, thereby reducing the light emitted from the area corresponding to the second portion 322 of the sub-pixel 3. In another example, the second sub-surface of the first conductive layer 323 located in the second portion 322 can be patterned so that the second sub-surface has a different morphology from the first sub-surface of the first conductive layer 323 located in the first portion 321, so as to reduce the reflection of light toward the light-emitting side by the second sub-surface of the first conductive layer 323 located in the second portion 322.

[0083] Referring back to Figure 3, each sub-pixel 3 may further include a second electrode 35 located on the side of the light-emitting function 34 away from the back plate 31. In some embodiments of the present disclosure, the second electrode 35 may include a transparent layer and a semi-reflective and semi-transparent layer. In some embodiments, the semi-reflective and semi-transparent layer may be located on the side of the light-emitting functional layer away from the back plate, and the transparent layer may be located on the semi-reflective and semi-transparent layer. The semi-reflective and semi-transparent layer may transmit a portion of the light from the light-emitting functional layer for displaying images. The semi-reflective and semi-transparent layer may also reflect another portion of the light from the light-emitting functional layer toward the direction of the first electrode. When the distance between the first electrode 32 and the semi-reflective and semi-transparent layer meets the strong microcavity condition, the light output intensity of the effective light-emitting area of ​​each sub-pixel (especially the central area of ​​the effective light-emitting area) can be improved.

[0084] In some examples, the semi-reflective and semi-transparent layer may include a metal layer, especially a metal layer with a low work function, such as Ag, Al, Li, Mg, Ca, and In layers. In other examples, the semi-reflective and semi-transparent layer may include a metal alloy layer, such as. In optional embodiments, the semi-reflective and semi-transparent layer may be made of a metal or alloy material with a low work function, such as MgAg alloy and LiAl alloy. Using a metal alloy to form a semi-reflective and semi-transparent layer can prevent oxidation, improve stability, extend service life, etc. In some exemplary embodiments, the thickness of the semi-reflective and semi-transparent layer can be 10-100A, in particular 10-70A. The reflectivity of the semi-reflective and semi-transparent layer can be 30%-80%.

[0085] In some embodiments, the transparent layer may include a transparent metal oxide such as ITO, ZnO, AZO (Al:ZnO).

[0086] In some embodiments of the present disclosure, the first electrode may be an anode, and the second electrode may be a cathode.

[0087] In some cases, the display panel may appear to have a reddish cast, which may be caused by a large amount of red light emitted from the red sub-pixel (especially the edge area of ​​the red sub-pixel). In order to reduce the reddish cast of the display panel, first electrodes with different reflectivities can be provided for sub-pixels of different colors. In an exemplary embodiment, the reflectivity of the edge area of ​​the first part of the first electrode of the red sub-pixel can be less than the reflectivity of the edge area of ​​the first part of the first electrode of the green sub-pixel and the reflectivity of the edge area of ​​the first part of the first electrode of the blue sub-pixel, so as to reduce the amount of red light emitted from the edge area of ​​the effective light-emitting area of ​​the red sub-pixel, thereby reducing or even eliminating the reddish cast of the display panel.

[0088] In some embodiments of the present disclosure, the display panel may further include other film layers not shown in the figures, such as a first encapsulation layer, a color filter layer, a second encapsulation layer and a transparent cover. The first encapsulation layer may cover the second electrode. For example, the first encapsulation layer may include two inorganic layers and an organic layer between the two inorganic layers. The color filter layer is provided on the side of the first encapsulation layer away from the second electrode, and the color filter layer includes a filter area corresponding to each first electrode one by one, and the filter area has multiple colors, such as red, blue and green. The second encapsulation layer may cover the color filter layer, and its structure may be the same as that of the first encapsulation layer. The transparent cover may cover the second encapsulation layer, and its material may be glass or material.

[0089] In some embodiments of the present disclosure, the radius R of the central area 3211 of the first portion 321 (corresponding to the effective light-emitting area of ​​the sub-pixel) is: R = the width of the opening of the pixel definition layer - 2 * the thickness of the light-emitting functional layer * tanθ, where θ is the incident angle of the light emitted by the light-emitting functional layer 34 on the first electrode 32. Within this radius R, since the distance between the first electrode 32 and the second electrode 35 meets the strong microcavity condition, the light extraction rate of the sub-pixel within this radius is relatively high. Outside this radius, due to process conditions or other factors, the distance between the first electrode 32 and the second electrode 35 or the wavelength of the light does not meet the strong microcavity condition. Therefore, in order to improve the light extraction rate of the sub-pixel outside this radius, some embodiments of the present disclosure set the reflectivity of the edge area 3212 of the first portion 321 of the first electrode 32 outside this radius to be larger, so as to enhance the light extraction rate of the edge area of ​​the sub-pixel 3, thereby improving the light extraction uniformity of the effective light-emitting area of ​​the sub-pixel 3.

[0090] An embodiment of the present disclosure further provides a display device, comprising a display panel according to one or more embodiments of the present disclosure, such as at least one display panel of one or more embodiments disclosed in detail above. Therefore, for optional embodiments of the display device, reference may be made to the embodiments of the display panel. Figure 10 schematically illustrates a display device according to one or more embodiments of the present disclosure. As shown in Figure 10, the display device 100 may include a display panel 101 described in accordance with any of the embodiments of the present disclosure relating to the display panel and a drive circuit 102 for providing a drive signal for driving the display panel.

[0091] The foregoing description of the embodiments is provided above for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present application. The individual elements or features of a particular embodiment are generally not limited to a particular embodiment, but, where appropriate, these elements and features are interchangeable and can be used in selected embodiments, even if not specifically shown or described. Also, it is possible to change in many ways. This change cannot be considered to be out of the present application, and all such modifications are included within the scope of the present application.

Claims

1. A display panel, comprising a plurality of sub-pixels, each sub-pixel comprising: Back panel; and A first electrode is located on the back plate, wherein the first electrode includes a central area and an edge area surrounding the central area, wherein a reflectivity of the central area of ​​the first electrode is different from a reflectivity of the edge area of ​​the first electrode.

2. The display panel according to claim 1, wherein: Each sub-pixel also includes: A pixel definition layer is located on the backplane, and the pixel definition layer has an opening exposing a portion of the first electrode, so that the first electrode has a first portion exposed by the opening and a second portion covered by the pixel definition layer.

3. The display panel according to claim 2, wherein: The central region of the first electrode includes the central region of the first portion, and the edge region of the first electrode includes the edge region of the first portion, and wherein a reflectivity of the central region of the first portion is less than a reflectivity of the edge region of the first portion.

4. The display panel according to claim 2, wherein: A central region of the first electrode includes the first portion, an edge region of the first electrode includes the second portion, and a reflectivity of the second portion of the first electrode is lower than a reflectivity of the first portion of the first electrode.

5. The display panel according to claim 3 or 4, wherein: The first electrode comprises: a first conductive layer located on the back plate; A second conductive layer located on a side of the first conductive layer away from the back plate; and A third conductive layer is located on a side of the second conductive layer away from the back plate, wherein the reflectivity of the first conductive layer is greater than the reflectivity of the second conductive layer and the third conductive layer.

6. The display panel according to claim 5, wherein: The first conductive layer and the third conductive layer are located at the first portion and the second portion of the first electrode, and the second conductive layer is located at a central area of ​​the first portion and the second portion.

7. The display panel according to claim 6, wherein: The first conductive layer includes a stacked structure of at least one of a metal or an alloy and a metal nitride, the second conductive layer includes a metal nitride, and the third conductive layer includes a transparent metal oxide.

8. The display panel according to claim 7, wherein: The first conductive layer includes a stacked structure of a titanium layer, a titanium nitride layer, and an aluminum layer, the second conductive layer includes a titanium nitride layer, and the third conductive layer includes an indium tin oxide layer.

9. The display panel according to claim 8, wherein: The aluminum layer includes an aluminum alloy layer.

10. The display panel according to claim 9, wherein: The material of the aluminum alloy in the central area of ​​the first portion is different from that in the edge area of ​​the first portion, so that the reflectivity of the aluminum alloy in the edge area of ​​the first portion is greater than the reflectivity of the aluminum alloy in the central area of ​​the first portion.

11. The display panel according to claim 8, wherein: A thickness of the first conductive layer in a central region of the first portion is smaller than a thickness of the first conductive layer in an edge region of the first portion.

12. The display panel according to claim 11, wherein: The thickness of the aluminum layer in a central region of the first portion is smaller than the thickness of the aluminum layer in an edge region of the first portion.

13. The display panel according to claim 5, wherein: The first electrode further includes an anti-reflection layer or a light absorbing layer located in the second portion and between the first conductive layer and the second conductive layer.

14. The display panel according to claim 5, wherein: The surface of the first conductive layer away from the back plate includes a first sub-surface located in the first portion and a second sub-surface located in the second portion, wherein the roughness of the second sub-surface is greater than the roughness of the first sub-surface.

15. The display panel according to claim 5, wherein: The surface of the first conductive layer away from the back plate includes a first sub-surface located in the first part and a second sub-surface located in the second part, wherein the first sub-surface includes a central part located in the central area of ​​the first part and an edge part located in the edge area of ​​the first part, and wherein the roughness of the edge part of the first sub-surface is smaller than the roughness of the central part of the first sub-surface.

16. The display panel according to claim 3 or 4, wherein: Each sub-pixel also includes: a light-emitting functional layer located on a side of the pixel definition layer away from the backplane; and A second electrode is located on a side of the light emitting functional layer away from the back plate.

17. The display panel according to claim 16, wherein: The radius R of the central area of ​​the first part satisfies: R=the width of the opening of the pixel definition layer-2*the thickness of the light-emitting function layer*tanθ, Wherein, θ is the incident angle of light emitted by the light-emitting functional layer on the first electrode.

18. The display panel according to claim 16, wherein: The second electrode includes a transparent layer and a semi-reflective and semi-transmissive layer.

19. The display panel according to claim 18, wherein: The transparent layer includes a transparent metal oxide, and the transflective layer includes a metal or an alloy.

20. The display panel according to claim 19, wherein: The thickness of the alloy layer is 10A-100A.

21. The display panel according to claim 3 or 4, wherein: The sub-pixels include a red sub-pixel, a green sub-pixel and a blue sub-pixel, wherein a reflectivity of an edge region of a first portion of a first electrode of the red sub-pixel is less than a reflectivity of an edge region of a first portion of a first electrode of the green sub-pixel and a reflectivity of an edge region of a first portion of a first electrode of the blue sub-pixel.

22. A display device comprising the display panel according to any one of claims 1 to 21.

Images