Display substrate, display device and preparation method thereof

Abstract

The application provides a display substrate, a display device and a preparation method thereof. The display substrate comprises a substrate and a plurality of anode structures arranged in an array on the substrate. The anode structure comprises a first electrode layer, a reflective electrode layer and a second electrode layer which are stacked in sequence. The first electrode layer is arranged close to the substrate. The thicknesses of the reflective electrode layer and the first electrode layer are both smaller than the thickness of the second electrode layer. The thickness of the second electrode layer is thickened by the microcavity effect, so that the thickness of the second electrode layer is thick, and the problem of unstable hole injection caused by the too-thin second electrode layer is avoided. Meanwhile, the microcavity effect improves the reflectivity of the anode, and thus improves the light brightness of the entire display device.

Description

Technical Field

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

[0002] Organic light-emitting diodes (OLEDs) have been widely used in the display field due to their advantages such as high brightness, wide viewing angle, fast response speed, and flexible display capabilities. To improve the brightness of OLEDs, the anode reflectivity is typically increased by thinning the indium tin oxide (ITO) layer in the anode layer, thereby enhancing the brightness. However, thinning the ITO layer may impair hole injection efficiency. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a display substrate, a display device and a method for manufacturing the same.

[0004] To achieve the above objectives, the first aspect of this application provides a display substrate, including a substrate and a plurality of anode structures arrayed on the substrate. The anode structures include a first electrode layer, a reflective electrode layer and a second electrode layer stacked sequentially. The first electrode layer is disposed close to the substrate, and the thickness of the reflective electrode layer and the first electrode layer is smaller than the thickness of the second electrode layer.

[0005] Optionally, the thickness ratio of the first electrode layer, the reflective electrode layer, and the second electrode layer is 1-2:6-10:11-13.

[0006] Optionally, the thickness of the second electrode layer is

[0007] Optionally, the orthographic projection of the first electrode layer on the substrate and the orthographic projection of the reflective electrode layer on the substrate are both located within the orthographic projection of the second electrode layer on the substrate.

[0008] Optionally, the second electrode layer includes a first surface and a second surface, the second surface being connected to the reflective electrode layer, and the orthographic projection of the first surface on the substrate being located within the orthographic projection of the second surface on the substrate.

[0009] Optionally, the orthographic projection of the reflective electrode layer on the substrate is located within the orthographic projection of the first electrode layer on the substrate.

[0010] Optionally, along the direction from the second electrode layer toward the substrate, the orthogonal projections of the reflective electrode layer and the first electrode layer on the substrate gradually increase.

[0011] Optionally, the distance between the edge of the orthographic projection of the second surface on the substrate and the edge of the orthographic projection of the reflective electrode layer on the substrate is 0.08 to 0.12 μm.

[0012] Optionally, the surface of the second electrode layer away from the substrate includes a first region and a second region, wherein the first region is used to connect with the light-emitting layer of the display substrate;

[0013] It also includes a pixel definition layer that covers the sidewalls of the anode structure, the second region, and the substrate located between two adjacent anode structures.

[0014] Optionally, the thickness of the pixel definition layer is

[0015] A second aspect of this application provides a method for preparing a display substrate, comprising:

[0016] Multiple arrayed anode structures are formed on one side of a substrate. The anode structures include a first electrode layer, a reflective electrode layer, and a second electrode layer stacked sequentially. The first electrode layer is disposed close to the substrate. The thickness of the reflective electrode layer and the first electrode layer is smaller than the thickness of the second electrode layer.

[0017] Optionally, the method further includes etching the first electrode layer and the reflective electrode layer inward to form an inner notch, so that the orthographic projection of the first electrode layer on the substrate and the orthographic projection of the reflective electrode layer on the substrate are both located within the orthographic projection of the second electrode layer on the substrate.

[0018] Optionally, it also includes:

[0019] A pixel definition layer is deposited on the top and sidewalls of the anode structure and on the substrate located between two adjacent anode structures;

[0020] An opening is made in the pixel definition layer to expose the second electrode layer.

[0021] A third aspect of this application provides a display device, comprising a display substrate as described in any of the first aspects or a display substrate prepared according to any of the second aspects, wherein the display device is an organic light-emitting diode display device.

[0022] As can be seen from the above, the display substrate, display device and its fabrication method provided in this application have an anode structure comprising a first electrode layer, a reflective electrode layer and a second electrode layer stacked sequentially. The thickness of the reflective electrode layer and the first electrode layer is smaller than the thickness of the second electrode layer. This application utilizes the microcavity effect to thicken the second electrode layer, making the second electrode layer thicker and avoiding the problem of unstable hole injection caused by the second electrode layer being too thin. At the same time, the microcavity effect increases the reflectivity of the anode, thereby improving the light output brightness of the entire display device. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a first structure of a display substrate according to an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of a second structure of the display substrate according to an embodiment of this application;

[0026] Figure 3 This is a schematic diagram illustrating the principle of the microcavity effect in an embodiment of this application;

[0027] Figure 4 The figure shows the experimental results of the reflectivity of different colors of light under different thicknesses of the second electrode layer according to the embodiments of this application. In the figure, the horizontal axis is the thickness of the second electrode layer and the vertical axis is the reflectivity.

[0028] Figure 5 This is a schematic diagram of a third structure of the display substrate according to an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a fourth structure of the display substrate according to an embodiment of this application;

[0030] Figure 7 This is a schematic diagram of a fifth structure of the display substrate according to an embodiment of this application;

[0031] Figure 8 This is a schematic diagram of a sixth structure of a display substrate according to an embodiment of this application;

[0032] Figure 9 This is a schematic diagram of a first structure during the fabrication process of the display substrate according to an embodiment of this application;

[0033] Figure 10This is a schematic diagram of a second structure in the fabrication process of the display substrate according to an embodiment of this application.

[0034] In the figure, 1 is the substrate; 2 is the anode structure; 21 is the second electrode layer; 211 is the first region; 212 is the second region; 22 is the reflective electrode layer; 23 is the first electrode layer; and 3 is the pixel definition layer. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0036] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0037] Common OLED light-emitting devices employ a "sandwich" structure, meaning the OLED light-emitting device includes an OLED anode and an OLED cathode positioned opposite each other, and an OLED light-emitting layer sandwiched between the OLED anode and OLED cathode. In OLED display devices, the OLED light-emitting devices are typically arrayed on a substrate. The OLED anode is usually located on the side of the OLED light-emitting layer facing the substrate, i.e., the bottom of the OLED; the OLED cathode is usually located on the side of the OLED light-emitting layer away from the substrate, i.e., the top of the OLED.

[0038] With the continuous development of display technology, the market demand for micro-display products such as Micro OLED (Micro Organic Light Emitting Display) is increasing. To achieve high pixel density, the anode structure of Micro OLED micro-display devices must meet high-precision process requirements. High-precision processes are achieved through photolithography combined with etching. Because wet etching results in significant image loss and its precision is far inferior to dry etching, dry etching is currently the preferred method for anode etching. To support dry etching, the anode material must be easily etched using dry etching and possess properties such as high work function, high reflectivity, and good conductivity. Therefore, the preferred anode structure is currently ITO+Al+Ti. This structure is easy to dry etch and can achieve high PPI requirements, but its reflectivity is slightly lower.

[0039] However, OLED near-eye displays require the anode to have high reflectivity, especially in the blue light band. Therefore, related technologies improve transmittance and thus anode reflectivity by thinning the ITO layer in the anode to a thickness less than that of the Al and Ti layers. However, the ITO layer is susceptible to damage during etching and cleaning processes in the pixel definition layer (PDL) and resonant half-bridge circuit (LLC). An excessively thin ITO layer is prone to insufficient film thickness after damage, and it is also prone to pinholes, which impairs hole injection efficiency.

[0040] Based on this, this application provides a display substrate, a display device and a method for fabricating the same, which utilizes the microcavity effect to thicken the second electrode layer, thereby avoiding the problem of impaired hole injection efficiency and improving the light output brightness of the display device.

[0041] See Figure 1 This application provides a display substrate, including a substrate 1 and a plurality of anode structures 2 arrayed on the substrate 1. The anode structure 2 includes a first electrode layer 23, a reflective electrode layer 22 and a second electrode layer 21 stacked in sequence. The first electrode layer 23 is disposed close to the substrate 1. The thickness of the reflective electrode layer 22 and the first electrode layer 23 is less than the thickness of the second electrode layer 21.

[0042] Specifically, the substrate 1 can support and protect various components of the display substrate. The substrate 1 can be formed of sapphire (Al2O3), silicon nitride, Si, GaAs, ZnO, glass, quartz, ceramic, or a flexible plastic material. For example, when the substrate 1 is formed of a plastic material, it can be formed of polyimide. The substrate 1 can be flexible, stretchable, foldable, bendable, and / or rollable, so the display substrate can also be flexible, stretchable, foldable, bendable, and / or rollable.

[0043] Multiple anode structures 2 are arrayed on the substrate 1, with openings between adjacent anode structures 2 to prevent crosstalk between adjacent anode structures 2 and light-emitting devices. The cross-sectional area of ​​the openings can be a regular rectangular structure (e.g., Figure 2 As shown), it can also be a trapezoidal structure, an inverted trapezoidal structure, or other irregular structures (such as...). Figure 1 (as shown), etc., are not limited here.

[0044] The anode structure 2 includes a first electrode layer 23, a reflective electrode layer 22, and a second electrode layer 21 stacked sequentially. The first electrode layer 23 is disposed close to the substrate 1. The first electrode layer 23 can be a metal electrode layer or an ITO electrode layer, used to connect the substrate 1 and other electrode layers of the anode structure 2. The second electrode layer 21 can be an ITO electrode, and the reflective electrode layer 22 can be an electrode with excellent light reflection characteristics, such as a silver electrode, an aluminum electrode, or a molybdenum electrode, to ensure that the reflective electrode layer 22 has excellent light reflection efficiency, thereby effectively improving the luminous efficiency of the display substrate. The reflective electrode layer 22 can effectively reflect the emitted light of the corresponding light-emitting layer while emitting light, thereby effectively improving the luminous efficiency of the light-emitting layer. For example, the first electrode layer 23 is a Ti layer, the reflective electrode layer 22 is an Al layer, and the second electrode layer 21 is an ITO layer. This can improve the light emission efficiency of the display substrate and ensure good connectivity between the substrate 1 and the anode structure 2, as well as between the various electrode layers in the anode structure 2.

[0045] The thickness of both the reflective electrode layer 22 and the first electrode layer 23 is less than the thickness of the second electrode layer 21. Specifically, the thickness of the reflective electrode layer 22 and the first electrode layer 23 can be the same or different, but the thickness of both the reflective electrode layer 22 and the first electrode layer 23 is less than the thickness of the second electrode layer 21.

[0046] In this application, the thickness of the second electrode layer 21 is increased. Even if the second electrode layer 21 is damaged by etching and cleaning during the pixel definition layer 3 and resonant half-bridge circuit process, the second electrode layer 21 will not be too thin, resulting in insufficient film thickness. This avoids the problem of unstable hole injection caused by the second electrode layer 21 being too thin.

[0047] Meanwhile, the thickness of the second electrode layer 21 is increased by utilizing the microcavity effect in this application. The microcavity effect increases the reflectivity of the anode. Even if the thickness of the second electrode layer 21 is increased, it will not lead to a decrease in reflectivity. On the contrary, it will increase the reflectivity of the anode, thereby increasing the light output brightness of the entire display device.

[0048] In a specific implementation, an organic light-emitting layer and a cathode layer are sequentially disposed on the side of the anode structure 2 away from the substrate 1. The anode structure 2, the organic light-emitting layer, and the cathode layer together form the light-emitting device of the display device.

[0049] An optical microcavity places the light-emitting area within a resonant cavity composed of a total reflection film and a semi-reflective film. Since the thickness of an organic light-emitting device can be comparable to the wavelength of light, the semi-transparent composite cathode (i.e., the cathode layer) can be considered as a semi-reflective film. Combined with the total reflection anode (i.e., anode structure 2), the light-emitting device exhibits a microcavity effect. Because the semi-transparent cathode layer has a certain light reflectivity, a microcavity structure is formed between it and the total reflection anode structure 2. Light of a certain wavelength will be amplified and narrowed within the microcavity.

[0050] In this application, the microcavity effect is utilized to enhance light of various wavelengths within the microcavity structure formed between the cathode and anode structures 2, thereby improving the light reflectivity of the anode structure 2 and ultimately enhancing the light extraction efficiency and brightness of the entire display device.

[0051] In some embodiments, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1-2:6-10:11-13.

[0052] Preferably, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1–2:7–8:11.5–12.5. More preferably, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1:7:12.

[0053] Specifically, when the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1–2:6–10:11–13, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is appropriate. This allows for an increase in the thickness of the second electrode layer 21, avoiding the problem of unstable hole injection caused by an excessively thin second electrode layer 21. Simultaneously, the thickness of the second electrode layer 21 meets the requirements of the microcavity effect, enabling the enhancement of light of various wavelengths within the microcavity structure formed between the cathode and anode structures 2, thereby improving the light extraction efficiency and brightness of the entire display device. Preferably, when the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1–2:7–8:11.5–12.5, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is optimal. The thickness of the second electrode layer 21 is neither too thin nor too thick, effectively improving the light extraction efficiency and brightness of the display device. When the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is 1:7:12, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22, and the second electrode layer 21 is optimal. This can significantly improve the light extraction efficiency and brightness of the display device. At the same time, it can save materials and reduce manufacturing costs while avoiding the instability of hole injection.

[0054] For example, the thickness ratio of the first electrode layer 23, the reflective electrode layer 22 and the second electrode layer 21 can be 1:6:11, 1:10:13, 2:7:11, 2:10:13, 1.5:7:12, 1.8:8:11.5, 1.9:9:12, 1:7:12, etc.

[0055] The first electrode layer 23 serves as an interconnect layer connecting the substrate 1 and other electrode layers of the anode structure 2. If the thickness of the first electrode layer 23 is too thin, the adhesion of the first electrode layer 23 will be too weak, and there is a risk of film peeling. If the thickness of the first electrode layer 23 is too thick, it will increase the anode series resistance, causing the light-emitting device to boost voltage and reduce the light extraction efficiency.

[0056] The reflective electrode layer 22 is used to reflect the emitted light from the light-emitting layer. If the thickness of the reflective electrode layer 22 is too thin, it will increase the transmittance of the incident light, leading to light loss. Experiments have shown that, based on a certain thickness, even if the thickness of the reflective electrode layer 22 is further increased, the light reflectivity will not continue to increase. Therefore, without increasing the thickness of the reflective electrode layer 22, it is unnecessary to further increase the reflectivity, thus avoiding waste of reflective electrode material. Furthermore, if the thickness of the reflective electrode layer 22 is too thick, the sputtering time during its fabrication will be too long. As the sputtering time increases, the controllability of the particles weakens, affecting the performance of the resulting film.

[0057] In some embodiments, the thickness of the second electrode layer 21 is The thickness of the first electrode layer 23 is The thickness of the reflective electrode layer 22 is

[0058] Preferably, the thickness of the second electrode layer 21 is The thickness of the first electrode layer 23 is The thickness of the reflective electrode layer 22 is More preferably, the thickness of the second electrode layer 21 is The thickness of the first electrode layer 23 is The thickness of the reflective electrode layer 22 is

[0059] For example, the thickness of the second electrode layer 21 can be The thickness of the first electrode layer 23 can be... The thickness of the reflective electrode layer 22 can be... wait.

[0060] Specifically, this application utilizes the microcavity effect to achieve thin-film interference, see [link to relevant documentation]. Figure 3 The thin-film interference structure mainly includes a first reflecting surface, a second reflecting surface, and the entire region of the second electrode layer 21. The first reflecting surface is the interface between the second electrode layer 21 and the upper film layer, and the second reflecting surface is the interface between the second electrode layer 21 and the reflecting electrode layer 22. Assume the refractive index of the upper film layer is n1, the refractive index of the second electrode layer 21 is n, the refractive index of the reflecting electrode layer 22 is n2, and the thickness of the second electrode layer 21 is h. When incident light passes through the first reflecting surface, part of it is reflected to form the first reflected light beam L1, and the other part of the incident light passes through the first reflecting surface and is reflected at the second reflecting surface to form the second reflected light beam L2. The second reflected light beam propagates in the second electrode layer 21, creating an optical path difference with the first reflected light beam. When the optical path difference Kλ = 2hn (K = 1, 2, 3...; λ is the wavelength of the incident light), interference is enhanced; when Kλ + λ / 2 = 2hn, interference is destructive. Therefore, interference enhancement can be achieved as long as Kλ = 2hn, thus improving the light extraction efficiency even with an increase in the thickness of the second electrode layer 21.

[0061] The refractive indices of the second electrode layer 21 in the blue, green, and red light bands are 1.91, 1.85, and 1.76, respectively. Based on Kλ = 2hn, the film thicknesses of the second electrode layer 21 corresponding to the reflection peaks of blue, green, and red light can be calculated as follows:

[0062] See Figure 4 , Figure 4 The graph shows the experimental results of reflectivity of various colors of light under different thicknesses of the second electrode layer 21. Figure 4 It can be seen that the reflectivity of red light is less affected by destructive forces within the period. arrive The reflectivity variation range is small within the range, while the variation period of blue light is relatively small, greater than... Afterwards, the reflectivity drops sharply, therefore the thickness of the second electrode layer 21 is... The thickness is most reasonable when the thickness of the second electrode layer 21 is within the range specified in the original text. At that time, the reflectivity of green and blue light both exceeded 90%, while the reflectivity of red light also reached 87%.

[0063] In related technologies, to improve light extraction efficiency, the ITO layer is thinned to... like Figure 4 As shown, when the thickness of the ITO layer is At that time, the reflectance of blue light was 80%, that of green light was 85%, and that of red light was 87%.

[0064] Compared with related technologies, this application increases the thickness of the second electrode layer 21 to [amount missing]. At that time, the reflectivity of green and blue light increased significantly, while the reflectivity of red light remained basically unchanged, thereby improving the light extraction efficiency of the entire display substrate.

[0065] In some embodiments, see Figure 5 The orthographic projection of the first electrode layer 23 on the substrate 1 and the orthographic projection of the reflective electrode layer 22 on the substrate 1 are both located within the orthographic projection of the second electrode layer 21 on the substrate 1.

[0066] Specifically, the orthographic projections of the first electrode layer 23 and the reflective electrode layer 22 on the substrate 1 are both located within the orthographic projections of the second electrode layer 21 on the substrate 1. This results in a smaller first opening width between adjacent second electrode layers 21, while the width of the second opening between adjacent reflective electrode layers 22 is greater than the width of the first opening. Simultaneously, the width of the third opening between adjacent first electrode layers 23 is also greater than the width of the first opening. This creates a "smaller at the top, larger at the bottom" structure between adjacent anode structures 2, providing better isolation and preventing crosstalk between adjacent light-emitting devices (or pixel units, where the pixel unit includes the light-emitting device) and their charge generation layers. Furthermore, in this application, the increased thickness of the second electrode layer 21 results in a greater opening depth between adjacent anode structures 2, increasing the gap between the pixel surface and the substrate 1 and providing an even better isolation effect.

[0067] The orthographic projection of the first electrode layer 23 on the substrate 1 and the orthographic projection of the reflective electrode layer 22 on the substrate 1 can be the same (e.g., Figure 5 As shown), they can also be different (e.g. Figure 6 and Figure 7 As shown in the figure, it is acceptable as long as the orthogonal projections of both on the substrate 1 are smaller than the orthogonal projection of the second electrode layer 21 on the substrate 1, and no limitation is made here.

[0068] In some embodiments, see Figure 6 The second electrode layer 21 includes a first surface and a second surface. The second surface is connected to the reflective electrode layer 22. The orthographic projection of the first surface on the substrate 1 is located within the orthographic projection of the second surface on the substrate 1.

[0069] Specifically, the orthographic projection of the first surface on the substrate 1 lies within the orthographic projection of the second surface on the substrate 1, meaning the surface area of ​​the second surface is greater than that of the first surface. Since both the first and second surfaces have larger surface areas than the surface area of ​​the surface where the reflective electrode layer 22 connects to the second electrode layer 21 (hereinafter referred to as the third surface), the surface areas of the second, first, and third surfaces gradually decrease. Thus, without affecting pixel density, the difference in surface area between the second and third surfaces can be maximized, thereby increasing the area of ​​the region on the second surface not connected to the reflective electrode layer 22. During subsequent deposition of the charge generation layer, due to limitations of the deposition process, the charge generation layer will not be deposited on this region. This isolates the charge generation layer between adjacent light-emitting devices, thereby preventing inter-pixel crosstalk between adjacent light-emitting devices. Without affecting pixel density, the larger this region, the better it can block inter-pixel crosstalk.

[0070] In some embodiments, the distance between the edge of the orthographic projection of the second surface on the substrate 1 and the edge of the orthographic projection of the reflective electrode layer 22 on the substrate 1 is 0.08 to 0.12 μm.

[0071] Specifically, the distance between the edge of the orthographic projection of the second surface on the substrate 1 and the edge of the orthographic projection of the reflective electrode layer 22 on the substrate 1 is preferably 0.09 to 0.11 μm. For example, this distance can be 0.08 μm, 0.09 μm, 0.10 μm, 0.11 μm, 0.12 μm, etc.

[0072] When the distance is within the range of 0.08 to 0.12 μm, that is, when the inward etching size of the reflective electrode layer 22 is within the range of 0.08 to 0.12 μm, it can effectively block inter-pixel crosstalk and facilitate the manufacturing process. When the distance is less than 0.08 μm, the blocking effect is not good enough and inter-pixel crosstalk may occur; when the distance is greater than 0.12 μm, it is not conducive to manufacturing.

[0073] In some embodiments, the distance between two adjacent second electrode layers 21 is 0.7 to 0.9 μm, which can increase the pixel density while ensuring the blocking effect.

[0074] In some embodiments, such as Figure 7 As shown, the orthographic projection of the reflective electrode layer 22 on the substrate 1 is located within the orthographic projection of the first electrode layer 23 on the substrate 1.

[0075] Specifically, the orthographic projection of the reflective electrode layer 22 on the substrate 1 lies within the orthographic projection of the first electrode layer 23 on the substrate 1. This smaller orthographic projection of the reflective electrode layer 22 on the substrate 1 allows for a larger area of ​​the second surface region not connected to the reflective electrode layer 22, thus increasing the width of the opening between adjacent reflective electrode layers 22 and better blocking inter-pixel crosstalk. Simultaneously, compared to the reflective electrode layer 22, the larger orthographic projection of the first electrode layer 23 on the substrate 1 enhances the adhesion of the first electrode layer 23, strengthens the connection between the anode structure 2 and the substrate 1, and enhances the connection between the first electrode layer 23 and the reflective electrode layer 22, avoiding the risk of film peeling.

[0076] In some embodiments, see continue to see Figure 1 Along the direction from the second electrode layer 21 toward the substrate 1, the orthogonal projections of the reflective electrode layer 22 and the first electrode layer 23 on the substrate 1 gradually increase.

[0077] Specifically, the orthographic projections of the reflective electrode layer 22 and the first electrode layer 23 on the substrate 1 gradually increase, that is, the cross-sectional area of ​​the reflective electrode layer 22 and the first electrode layer 23 is trapezoidal, and the sides of the reflective electrode layer 22 and the first electrode layer 23 are on the same plane, which is beneficial to subsequent manufacturing processes, facilitates the subsequent manufacturing of pixel definition layer 3, etc., and saves the manufacturing time and cost of the display substrate.

[0078] In some embodiments, such as Figure 8 As shown, the surface of the second electrode layer 21 away from the substrate 1 includes a first region 211 and a second region 212. The first region 211 is used to connect with the light-emitting layer of the display substrate. It also includes a pixel definition layer 3, which covers the sidewall of the anode structure 2, the second region 212 and the substrate 1 located between two adjacent anode structures 2.

[0079] Specifically, the pixel definition layer 3 covers the sidewall of the anode structure 2, the second region 212, and the substrate 1 located between two adjacent anode structures 2 to protect the anode structure 2 and prevent leakage from the anode sidewall.

[0080] In a specific implementation, an atomic layer deposition (ALD) apparatus can be used to coat the sidewalls of the anode structure 2, the second region 212, and the substrate 1 located between two adjacent anode structures 2 to form a pixel definition layer 3. For example, the pixel definition layer 3 can be made of Al2O3 material. The ALD apparatus has the characteristic of 100% step coverage, allowing Al2O3 material to be uniformly deposited on the sidewalls of the anode structure 2, the second region 212, and the substrate 1 located between two adjacent anode structures 2, forming a uniform and highly dense pixel definition layer 3.

[0081] In some embodiments, the thickness of the pixel definition layer 3 is

[0082] Specifically, when the thickness of pixel definition layer 3 is When the thickness of the pixel definition layer 3 is less than 1, it provides good protection for the anode structure 2. When the thickness is too thin, it is easily broken down, and the protection for the anode structure 2 is insufficient, making leakage on the sidewall of the anode structure 2 likely. When the thickness of the pixel definition layer 3 is greater than... If the pixel definition layer 3 is too thick, it will reduce the opening area between two adjacent anode structures 2 while ensuring pixel density, thus affecting the blocking effect and potentially causing crosstalk between adjacent light-emitting devices.

[0083] For example, the thickness of the pixel definition layer 3 can be wait.

[0084] This application also provides a method for preparing a display substrate, comprising:

[0085] Multiple arrayed anode structures 2 are formed on one side of a substrate 1. The anode structure 2 includes a first electrode layer 23, a reflective electrode layer 22, and a second electrode layer 21 stacked sequentially. The first electrode layer 23 is disposed close to the substrate 1. The thickness of the reflective electrode layer 22 and the first electrode layer 23 is smaller than the thickness of the second electrode layer 21.

[0086] Specifically, firstly, a substrate 1 is provided, and a first electrode layer 23, a reflective electrode layer 22, and a second electrode layer 21 are sequentially deposited on the substrate 1. The thicknesses of the reflective electrode layer 22 and the first electrode layer 23 are both less than the thickness of the second electrode layer 21, forming a structure as shown in the figure. Figure 9 The structure shown.

[0087] Secondly, through coating, exposure, development, and etching, in Figure 9The structure shown has an opening to form multiple arrayed anode structures 2 on one side of the substrate 1, such as... Figure 2 As stated above.

[0088] Next, through coating, exposure, development, and etching, the first electrode layer 23 and the reflective electrode layer 22 are etched inward to form an inner notch, such as... Figure 5 , Figure 6 , Figure 7 or Figure 1 As shown, the orthographic projection of the first electrode layer 23 on the substrate 1 and the orthographic projection of the reflective electrode layer 22 on the substrate 1 are both located within the orthographic projection of the second electrode layer 21 on the substrate 1.

[0089] Then, using an atomic layer deposition apparatus, a pixel definition layer 3 (e.g., ...) is deposited on the top and sidewalls of the anode structure 2, and on the substrate 1 located between two adjacent anode structures 2. Figure 10 As shown), an opening is then made in the pixel definition layer 3 to expose the second electrode layer 21 (as shown). Figure 8 (As shown).

[0090] Finally, the exposed surface of the second electrode layer 21 is treated with plasma containing oxidizing gases such as N2O, O2, and CF4 to fully oxidize it, increasing the enrichment of oxidizing ions on its surface and thus improving its work function. Simultaneously, after surface treatment, the thicker second electrode layer 21 is less susceptible to corrosion or damage from the oxidizing plasma to the reflective electrode layer 22.

[0091] In this application, the pixel definition layer 3 is directly deposited using an atomic layer deposition (ALD) apparatus. Compared to the traditional method of fabricating the pixel definition layer 3 using exposure, development, and etching steps, this simplifies the fabrication process, significantly improves production efficiency, and saves costs. Furthermore, compared to the traditional method of fabricating the pixel definition layer 3 using exposure, development, and etching steps, the pixel definition layer 3 deposited directly using the ALD apparatus in this application is thinner, thereby increasing the pixel aperture ratio, increasing the reflective area, and improving the display brightness of the display device.

[0092] In summary, the display substrate and its fabrication method described in this application utilize the microcavity effect to thicken the second electrode layer 21, thereby increasing the reflectivity of the blue and green light bands and improving the brightness of blue and green light. This solves the problems of low blue light brightness in the display device and unstable hole injection caused by the excessively thin second electrode layer 21. It simplifies the fabrication process of the pixel definition layer 3, reducing exposure, development, and etching processes compared to traditional processes, significantly improving production efficiency and saving costs. The high-density pixel definition layer 3 fabricated using atomic layer deposition equipment can reduce the thickness of the pixel definition layer 3, thereby increasing the pixel aperture ratio, increasing the reflective area, and improving the light output brightness of the display device. The thicker second electrode layer 21 increases the gap between the pixel surface and the substrate 1, and the opening formed by the inward etching of the reflective electrode layer 22 provides a better isolation effect. After surface treatment, the thicker second electrode layer 21 is less susceptible to corrosion or damage from oxidizing plasma.

[0093] This application also provides a display device, including the display substrate described in any of the above embodiments, wherein the display device is an organic light-emitting diode display device.

[0094] The display device can be a product with image display function, such as: monitor, television, billboard, digital photo frame, laser printer with display function, telephone, mobile phone, personal digital assistant (PDA), digital camera, portable camcorder, viewfinder, navigator, vehicle, large wall, home appliance, information query equipment (such as business query equipment of e-government, bank, hospital, power and other departments, monitor, etc.).

[0095] The display device has the technical effects described in any of the above embodiments, which will not be elaborated here.

[0096] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0097] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this disclosure as described above, which are not provided in detail for the sake of brevity.

[0098] This disclosure is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A display substrate, characterized in that, The device includes a substrate and multiple anode structures arrayed on the substrate. The anode structures include a first electrode layer, a reflective electrode layer, and a second electrode layer stacked sequentially. The first electrode layer is disposed close to the substrate. The thickness of both the reflective electrode layer and the first electrode layer is less than the thickness of the second electrode layer. The thickness of the second electrode layer is 1100~1300 Å. The thickness ratio of the first electrode layer, the reflective electrode layer, and the second electrode layer is 1~2:6~10:11~13. The orthographic projections of the first electrode layer and the reflective electrode layer on the substrate are both located within the orthographic projections of the second electrode layer on the substrate.

2. The display substrate according to claim 1, characterized in that, The second electrode layer includes a first surface and a second surface, the second surface being connected to the reflective electrode layer, and the orthographic projection of the first surface on the substrate being located within the orthographic projection of the second surface on the substrate.

3. The display substrate according to claim 2, characterized in that, The orthographic projection of the reflective electrode layer on the substrate lies within the orthographic projection of the first electrode layer on the substrate.

4. The display substrate according to claim 3, characterized in that, Along the direction from the second electrode layer toward the substrate, the orthogonal projections of the reflective electrode layer and the first electrode layer on the substrate gradually increase.

5. The display substrate according to claim 2, characterized in that, The distance between the edge of the orthographic projection of the second surface on the substrate and the edge of the orthographic projection of the reflective electrode layer on the substrate is 0.08~0.12μm.

6. The display substrate according to claim 1, characterized in that, The surface of the second electrode layer away from the substrate includes a first region and a second region, wherein the first region is used to connect with the light-emitting layer of the display substrate; It also includes a pixel definition layer that covers the sidewalls of the anode structure, the second region, and the substrate located between two adjacent anode structures.

7. The display substrate according to claim 6, characterized in that, The thickness of the pixel definition layer is 200~300Å.

8. A method for preparing a display substrate, characterized in that, include: Multiple arrayed anode structures are formed on one side of a substrate. The anode structure includes a first electrode layer, a reflective electrode layer, and a second electrode layer stacked sequentially. The first electrode layer is disposed close to the substrate. The thickness of the reflective electrode layer and the first electrode layer is smaller than the thickness of the second electrode layer. The thickness of the second electrode layer is 1100~1300 Å. The ratio of the thickness of the first electrode layer, the reflective electrode layer, and the second electrode layer is 1~2:6~10:11~13. The first electrode layer and the reflective electrode layer are etched inward to form an inner notch, so that the orthographic projection of the first electrode layer on the substrate and the orthographic projection of the reflective electrode layer on the substrate are both located within the orthographic projection of the second electrode layer on the substrate.

9. The preparation method according to claim 8, characterized in that, Also includes: A pixel definition layer is deposited on the top and sidewalls of the anode structure and on the substrate located between two adjacent anode structures; An opening is made in the pixel definition layer to expose the second electrode layer.

10. A display device, characterized in that, The display device includes the display substrate according to any one of claims 1 to 7 or the display substrate prepared according to any one of claims 8 to 9, wherein the display device is an organic light-emitting diode display device.

Images