Display panel

Abstract

According to the display panel, a stepped groove is formed in a first flat layer, and the depths of any two adjacent stepped sub-grooves are gradually increased in the direction from the edge of the groove to the center of the groove, so that a concave part is formed in a second flat layer, and a concave surface is formed in a first electrode. Based on the combination of the concave surface and the gravity effect, the risk that the material of the light-emitting functional layer is accumulated near the bottom of the side wall of the opening is reduced. According to the display panel, the mode that the second flat layer covers the stepped groove of the first flat layer is adopted, the concave smoothness and size of the concave part can be flexibly adjusted by adjusting the stage number, depth and width of the stepped sub-groove of the groove, and the concave smoothness and size of the concave part can be flexibly adjusted by adjusting the thickness and leveling property of the second flat layer. And the concave smoothness and the size of the concave part are further adjusted, so that a matched concave surface is obtained.

Description

Technical Field

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

[0002] The light-emitting layer materials of the current mainstream printed organic light-emitting diode panels are prone to the coffee ring effect, which causes the hole injection layer c1, hole transport layer c2 and light-emitting layer c3 to accumulate on the opening edge of the pixel definition layer c4. Figure 1 As shown, the film morphology of the light-emitting layer is affected, resulting in a change in the thickness ratio of the film layer at the edge of the pixel, which affects the light-emitting effect. Summary of the invention

[0003] The embodiments of the present application provide a display panel that can improve the uniformity of film formation while allowing for more flexible and precise adjustment of concave portions and concave surfaces.

[0004] An embodiment of the present application provides a display panel, comprising:

[0005] substrate;

[0006] a first flat layer, covering the substrate, the first flat layer being provided with a groove, the groove comprising a base sub-groove and a plurality of connected step sub-grooves, the plurality of step sub-grooves being located at the periphery of the base sub-groove, the depth of the base sub-groove being greater than the depth of the step sub-groove adjacent to the base sub-groove, and the depths of any two adjacent step sub-grooves increasing in a direction from the edge of the groove to the center of the groove;

[0007] A second flat layer covering a side of the first flat layer away from the substrate, wherein the second flat layer includes a concave portion covering the groove;

[0008] A first electrode is provided at least on a surface of the recessed portion away from the substrate, wherein a portion of the first electrode corresponding to the recessed portion is formed with a concave surface;

[0009] a pixel definition layer, disposed on a side of the second planar layer away from the substrate, the pixel definition layer being provided with an opening including the first electrode; and

[0010] The light-emitting functional layer is arranged in the opening and covers the first electrode.

[0011] Optionally, in some embodiments of the present application, the surface of the recessed portion away from the substrate includes a first concave arc surface located in the edge area, and the first concave arc surface corresponds to the multiple levels of the step sub-grooves; a second concave arc surface is formed on the portion of the concave surface corresponding to the first concave arc surface, and in the thickness direction of the display panel, the first concave arc surface, the second concave arc surface and the multiple levels of the step sub-grooves are stacked.

[0012] Optionally, in some embodiments of the present application, the surface of the concave portion away from the substrate further includes a first flat surface located in the middle area, and the first flat surface is connected to the first concave arc surface;

[0013] A second flat surface is formed on the concave surface corresponding to the first flat surface, and the second flat surface is connected to the second concave arc surface;

[0014] In the thickness direction of the display panel, the first flat surface, the second flat surface and the substrate sub-groove are stacked.

[0015] Optionally, in some embodiments of the present application, the width of the base sub-groove is greater than the width of the step sub-groove.

[0016] Optionally, in some embodiments of the present application, the surface of the concave portion away from the substrate further includes a third concave curved surface located in the middle area, the third concave curved surface is smoothly connected to the first concave curved surface, and the curvature of the third concave curved surface is less than or equal to the curvature of the first concave curved surface;

[0017] A fourth concave arc surface is formed at a portion of the concave surface corresponding to the third concave arc surface, the fourth concave arc surface is smoothly connected to the second concave arc surface, and a curvature of the fourth concave arc surface is less than or equal to a curvature of the second concave arc surface;

[0018] In the thickness direction of the display panel, the third concave curved surface, the fourth concave curved surface and the substrate sub-groove are stacked.

[0019] Optionally, in some embodiments of the present application, the width of the base sub-groove is less than or equal to twice the width of the step sub-groove.

[0020] Optionally, in some embodiments of the present application, in the direction from the edge of the groove to the center of the groove, the widths of any two adjacent steps of the step sub-grooves are equal.

[0021] Optionally, in some embodiments of the present application, in the direction from the edge of the groove to the center of the groove, the depth difference between any two adjacent steps of the step sub-grooves is equal;

[0022] Alternatively, in a direction from the edge of the groove to the center of the groove, the depth difference between two adjacent step sub-grooves decreases.

[0023] Optionally, in some embodiments of the present application, the depth difference between any two adjacent step sub-grooves is greater than or equal to 100 nanometers.

[0024] Optionally, in some embodiments of the present application, the first concave arc surface is a circular arc surface, and the second concave arc surface is a circular arc surface.

[0025] Optionally, in some embodiments of the present application, in a direction from the side wall of the opening toward the center of the opening, the curvature of the first concave arc surface decreases gradually, and the curvature of the second concave arc surface decreases gradually.

[0026] Optionally, in some embodiments of the present application, based on a plane parallel to the substrate surface, the sidewall of the opening has a slope angle, a tangent line at any point on the first concave arc surface has a first inclination angle, and a tangent line at any point on the second concave arc surface has a second inclination angle;

[0027] In a direction from the side wall of the opening to the center of the opening, the first inclination angle gradually decreases, the second inclination angle gradually decreases, and the maximum first inclination angle and the maximum second inclination angle are both smaller than the slope angle.

[0028] Optionally, in some embodiments of the present application, the second concave arc surface is connected to the side wall of the opening.

[0029] The display panel of the embodiment of the present application forms a stepped groove on the first flat layer, and utilizes the leveling and film shrinkage of the second flat layer so that the second flat layer forms a concave portion and the first electrode forms a concave surface. Based on the combination of the concave surface and the gravity effect, the climbing phenomenon of the material of the light-emitting functional layer is improved, and the risk of the material of the light-emitting functional layer accumulating near the bottom of the side wall of the opening is reduced.

[0030] Secondly, the display panel of the embodiment of the present application adopts the step-type groove of the first flat layer covered by the second flat layer, and the size of the concave part and the concave smoothness can be flexibly adjusted by adjusting the number of steps, depth and width of the step sub-grooves of the groove, and the size of the concave part and the concave smoothness can be further adjusted by adjusting the thickness and leveling property of the second flat layer to obtain a matching concave surface. That is, the concave part and the concave surface of the first electrode can be adjusted more flexibly and accurately.

[0031] In addition, based on the recess formed on the second flat layer, the first flat layer and the second flat layer can make up for the terrain step difference caused by the routing of the first electrode region, thereby reducing the impact on the film formation uniformity of the light-emitting functional layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the structure of a display panel in the prior art;

[0033] Figure 2 is a schematic diagram of the structure of a display panel provided in an embodiment of the present application;

[0034] Figure 3 yes Figure 2 A magnified schematic diagram of part A;

[0035] Figure 4 is a schematic diagram of the structure of the first flat layer and the second flat layer of the display panel provided in an embodiment of the present application;

[0036] Figure 5 is a schematic structural diagram of a second planar layer, a first electrode, and a pixel definition layer in a display panel provided in an embodiment of the present application;

[0037] Figure 6 is a schematic diagram of step B01 of the method for preparing a display panel provided in an embodiment of the present application;

[0038] Figure 7 is a schematic diagram of step B02 of the method for preparing a display panel provided in an embodiment of the present application;

[0039] Figure 8 is a schematic diagram of step B03 of the method for preparing a display panel provided in an embodiment of the present application;

[0040] Fig. 9 is a schematic diagram of step B04 of the method for preparing a display panel provided in an embodiment of the present application;

[0041] Fig.10 is a schematic diagram of step B05 of the method for preparing a display panel provided in an embodiment of the present application;

[0042] Fig.11 is another structural schematic diagram of a display panel provided in an embodiment of the present application;

[0043] Fig.12 yes Fig.11 Schematic diagram of the enlarged portion B. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, the various embodiments can be combined with each other but will not be repeated one by one, and in the absence of contrary instructions, the directional words used, such as "upper" and "lower", usually refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the drawings; while "inside" and "outside" refer to the outline of the device; the terms "first", "second", "third", etc. are used only as markings, and no numerical requirements are imposed or order is established.

[0045] The present application provides a display panel, which is described in detail below. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments.

[0046] Please refer to Figure 2 and Figure 3 An embodiment of the present application provides a display panel 100 , which includes a substrate 11 , a driving circuit layer 12 , a first flat layer 13 , a second flat layer 14 , a first electrode 15 , a pixel definition layer 16 , a light-emitting functional layer 17 and a second electrode 18 .

[0047] The driving circuit layer 12 is arranged on the substrate 11. The driving circuit layer 12 includes a thin film transistor TFT. Optionally, the thin film transistor TFT can be a top gate type, a bottom gate type or a double gate type. The thin film transistor TFT can also be a horizontal channel transistor or a vertical channel transistor.

[0048] In the display panel 100 of the embodiment of the present application, no specific limitation is imposed on the structure of the thin film transistor TFT.

[0049] exist Figure 2 and Figure 3 In the embodiment, the driving circuit layer 12 includes a buffer layer 121, an active layer 122, a first insulating layer 12a, a first metal layer 123, a second insulating layer 12b, a second metal layer 124, a third insulating layer 12c, a fourth insulating layer 12d, a third metal layer 125 and a fifth insulating layer 12f which are stacked in sequence. The first planar layer 13 covers a side of the fifth insulating layer 12f away from the substrate 11.

[0050] Optionally, in one or more embodiments, the display panel 100 may further include a wiring layer 19 , which is disposed on a side of the first planar layer 13 away from the substrate 11 . The second planar layer 14 covers the wiring layer 19 .

[0051] The first flat layer 13 covers the substrate 11. The first flat layer 13 is provided with a groove ac. The groove ac includes a base sub-groove a1 and a multi-level connected step sub-groove a2, and the multi-level step sub-groove a2 is located around the base sub-groove a1. The depth of the base sub-groove a1 is greater than the depth of the step sub-groove a2 adjacent to the base sub-groove a1. In the direction from the edge of the groove ac to the center of the groove ac, the depth of any two adjacent step sub-grooves a2 increases gradually.

[0052] The second planar layer 14 covers the first planar layer 13 on a side away from the substrate 11. The second planar layer 14 includes a concave portion ab covering the groove ac.

[0053] The first electrode 15 is provided at least on the surface of the recessed portion ab away from the substrate 11. The first electrode 15 has a concave surface 15a formed at a portion corresponding to the recessed portion ab.

[0054] The pixel definition layer 16 is disposed on a side of the second planar layer 14 away from the substrate 11 . The pixel definition layer 16 is provided with an opening 161 including the first electrode 15 .

[0055] The light emitting functional layer 17 is disposed in the opening 161 and covers the first electrode 15. The second electrode 18 is disposed on a side of the light emitting functional layer 17 away from the substrate 11.

[0056] One of the first electrode 15 and the second electrode 18 is an anode, and one of the first electrode 15 and the second electrode 18 is a cathode.

[0057] Optionally, in some embodiments, the light-emitting functional layer 17 includes only the light-emitting layer EML, but is not limited thereto. For example, based on the light-emitting functional layer 17 including the light-emitting layer EML, the light-emitting functional layer 17 may also include at least one of a hole injection layer HIL, a hole transport layer HTL, an electron transport layer ETL and an electron injection layer, or include other functional film layers.

[0058] It should be noted that the following will be Figure 2 This is explained as an example, but not limited to this.

[0059] exist Figure 2 and Figure 3 In the embodiment, the first electrode 15 is an anode, and the light emitting functional layer 17 includes a hole injection layer HIL, a hole transport layer HTL, a light emitting layer EML, and an electron transport layer ETL stacked on the first electrode 15 .

[0060] Optionally, the first electrode 15 may be a single-layer film layer, or a stacked structure of multiple film layers, such as ITO / Ag / ITO.

[0061] It can be understood that the display panel 100 of the embodiment of the present application forms a stepped groove ac on the first flat layer 13, and utilizes the leveling property and film shrinkage property of the second flat layer 14 so that the second flat layer 14 forms a concave portion ab and the first electrode 15 forms a concave surface 15a. Based on the combination of the concave surface 15a and the gravity effect, when printing at least part of the film layer of the light-emitting functional layer 17, the climbing phenomenon of the material of the light-emitting functional layer 17 is improved, and the risk of the material of the light-emitting functional layer 17 being accumulated near the bottom of the side wall of the opening 161 is reduced.

[0062] Secondly, because the formation of the stepped groove ac can be formed with the patterning of the first flat layer 13 using a mask template, no additional process is required. The display panel 100 of the embodiment of the present application uses the second flat layer 14 to cover the stepped groove ac of the first flat layer 13. The concave smoothness and size of the concave part ab can be flexibly adjusted by adjusting the number, depth and width of the step sub-grooves a2 of the groove ac. The concave smoothness of the concave part ab can also be further adjusted by adjusting the thickness and leveling property of the second flat layer 14 to obtain a matching concave surface 15a. That is, the concave part ab can be adjusted more flexibly and more accurately.

[0063] In addition, based on the recess ab formed on the second flat layer 14 , the first flat layer 13 and the second flat layer 14 can compensate for the terrain step difference caused by the routing of the first electrode 15 area, reducing the impact on the film formation uniformity of the light-emitting functional layer 17 .

[0064] Optionally, in some embodiments, the surface of the concave portion ab away from the substrate 11 includes a first concave curved surface b1 located in the edge region. The first concave curved surface b1 corresponds to the multi-step sub-groove a2. A second concave curved surface b2 is formed on the portion of the concave surface 15a corresponding to the first concave curved surface b1. In the thickness direction of the display panel 100, the first concave curved surface b1, the second concave curved surface b2 and the multi-step sub-groove a2 are stacked.

[0065] It can be understood that the display panel 100 of the embodiment of the present application forms a stepped groove ac on the first flat layer 13, and utilizes the leveling property and film shrinkage property of the second flat layer 14 so that the concave portion ab of the second flat layer 14 forms a first concave arc surface b1 and the first electrode 15 forms a second concave arc surface b2. Based on the combination of the second concave arc surface b2 and the gravity effect, when printing at least part of the film layer of the light-emitting functional layer 17, the climbing phenomenon of the material of the light-emitting functional layer 17 is improved, and the risk of the material of the light-emitting functional layer 17 being accumulated near the bottom of the side wall of the opening 161 is reduced.

[0066] Secondly, the display panel 100 of the embodiment of the present application adopts the method of covering the stepped groove ac of the first flat layer 13 with the second flat layer 14, and the curvature and size of the first concave arc surface b1 can be flexibly adjusted by adjusting the number, depth and width of the step sub-grooves a2 of the groove ac, and the curvature and size of the first concave arc surface b1 can be further adjusted by adjusting the thickness and leveling property of the second flat layer 14 to obtain a matching second concave arc surface b2. That is, the first concave arc surface b1 can be adjusted more flexibly and accurately.

[0067] In addition, the first concave surface b1 is formed on the second flat layer 14 , so that the first flat layer 13 and the second flat layer 14 can make up for the terrain step difference caused by the routing of the first electrode 15 area, reducing the impact on the film formation uniformity of the light-emitting functional layer 17 .

[0068] It should be noted that, in some embodiments, the first concave arc surface b1 can also be replaced by a first step surface in a multi-level form, and the second concave arc surface b2 can also be replaced by a second step surface in a multi-level form, as long as the thickness of each step of the first step surface is less than or equal to 50 nanometers, and the thickness of each step of the second step surface is less than or equal to the thickness of each step of the first step surface.

[0069] Optionally, in some embodiments of the present application, the surface of the concave portion ab away from the substrate 11 further includes a third concave curved surface b3 located in the middle area, and the third concave curved surface b3 is smoothly connected to the first concave curved surface b1. The curvature of the third concave curved surface b3 is less than or equal to the curvature of the first concave curved surface b1.

[0070] The portion of the concave surface 15a corresponding to the third concave arc surface b3 forms a fourth concave arc surface b4, and the fourth concave arc surface b4 is smoothly connected to the second concave arc surface b2. The curvature of the fourth concave arc surface b4 is less than or equal to the curvature of the second concave arc surface b2.

[0071] In the thickness direction of the display panel 100 , the third concave curved surface b3 , the fourth concave curved surface b4 , and the substrate sub-groove a1 are stacked.

[0072] It can be understood that the curvature of the third concave arc surface b3 is less than or equal to the curvature of the first concave arc surface b1, so that the curvature of the third concave arc surface b3 is lower than or equal to the curvature of the first concave arc surface b1, so that the third concave arc surface b3 maintains a relatively gentle curvature, thereby prompting the fourth concave arc surface b4 to also have a relatively gentle curvature.

[0073] The curvature of the fourth concave surface b4 is less than or equal to the curvature of the second concave surface b2, so that the curvature of the fourth concave surface b4 is less than or equal to the curvature of the second concave surface b2, so that the fourth concave surface b4 maintains a relatively gentle curvature, thereby improving the thickness uniformity of the light-emitting functional layer 17.

[0074] Optionally, the first concave curved surface b1 and the third concave curved surface b3 can each be one of a circular curved surface and a curved surface with a gradually changing curvature. The second concave curved surface b2 and the first concave curved surface b1 are the same type of curved surfaces, and the fourth concave curved surface b4 and the third concave curved surface b3 are the same type of curved surfaces.

[0075] exist Figure 2 and Figure 3In the embodiment, the first concave arc surface b1 and the third concave arc surface b3 are both arc surfaces, and the curvatures of the first concave arc surface b1 and the third concave arc surface b3 are the same; that is, the surface of the concave portion ab away from the substrate 11 is an arc surface. The second concave arc surface b2 and the fourth concave arc surface b4 are both arc surfaces, and the curvatures of the second concave arc surface b2 and the fourth concave arc surface b4 are the same; that is, the surface of the first electrode 15 away from the substrate 11 is an arc surface.

[0076] However, the display panel 100 of the present embodiment is not limited to Figure 2 structure, for example, the first concave arc surface b1, the second concave arc surface b2, the third concave arc surface b3 and the fourth concave arc surface b4 can all be arc surfaces with gradually changing curvature; or, two of the first concave arc surface b1, the second concave arc surface b2, the third concave arc surface b3 and the fourth concave arc surface b4 are circular arc surfaces, and the other two are arc surfaces with gradually changing curvature.

[0077] Optional, see Figure 4 In some embodiments of the present application, the width k1 of the base sub-groove a1 is less than or equal to the width k2 of the step sub-groove a2.

[0078] It should be understood that the width k2 of the step sub-groove a2 is the width of the groove bottom of the step sub-groove a2. For example, if the step sub-groove a2 is annular, the annular step sub-groove a2 is formed by a groove with a certain groove bottom width surrounding a circle. The larger the width k1 of the base sub-groove a1, the flatter the area of ​​the corresponding third concave arc surface b3 away from the first concave arc surface b1 by a certain distance, until it tends to be horizontal. Therefore, the width k1 of the base sub-groove a1 is selected to be less than or equal to the width k2 of the step sub-groove a2 to ensure that the third concave arc surface b3 is an arc surface as a whole.

[0079] Of course, in some embodiments, the width k1 of the base sub-groove a1 may be slightly larger than the width k2 of the step sub-groove a2. For example, the width k1 of the base sub-groove a1 may be between 1 and 2 times (including 2 times) the width k2 of the step sub-groove a2, so as to further improve the uniformity of the film formation of the light-emitting functional layer 17.

[0080] Optionally, in some embodiments of the present application, in the direction from the edge of the groove ac to the center of the groove ac, the widths k2 of any two adjacent step sub-grooves a2 are equal.

[0081] It can be understood that the widths of any step sub-grooves a2 are equal, so as to improve the uniformity of the curvature of the first concave arc surface b1 and make the continuity of the first concave arc surface b1 smoother.

[0082] Optionally, in some embodiments of the present application, in the direction from the edge of the groove ac to the center of the groove ac, the depth difference h1 between any two adjacent step sub-grooves a2 is equal.

[0083] It can be understood that the combination of the depth difference h1 between two adjacent step sub-grooves a2 and the width k2 of the step sub-grooves a2 determines the curvature and size of the first concave arc surface b1. Therefore, the depth difference h1 between any two adjacent step sub-grooves a2 is equal, which is convenient for improving the uniformity of the curvature of the first concave arc surface b1 and making the continuity of the first concave arc surface b1 smoother. For example, based on the equality of the width k2 of any step sub-grooves a2 and the equality of the depth difference h1 between any two adjacent step sub-grooves a2, the first concave arc surface b1 can form a circular arc surface.

[0084] Based on this, in some embodiments of the present application, the first concave arc surface b1 is a circular arc surface, and the second concave arc surface b2 is a circular arc surface.

[0085] Optionally, in some embodiments of the present application, the depth difference between two adjacent step sub-grooves a2 may decrease in the direction from the edge of the groove ac to the center of the groove ac.

[0086] It can be understood that as the depth difference decreases, the step difference between the step sub-grooves a2 becomes more gradual towards the center, so that the curvature of the first concave arc surface b1 closer to the center of the groove ac becomes more gradual, thereby facilitating the formation of the first concave arc surface b1 with decreasing curvature, so as to further improve the film formation uniformity of the light-emitting functional layer 17.

[0087] Based on this, in some embodiments of the present application, in a direction from the side wall of the opening 161 to the center of the opening 161 , the curvature of the first concave arc surface b1 decreases gradually, and the curvature of the second concave arc surface b2 decreases gradually.

[0088] Optionally, in some embodiments of the present application, the depth difference h1 between any two adjacent step sub-grooves a2 is greater than or equal to 100 nanometers.

[0089] It is understandable that the materials of the first flat layer 13 and the second flat layer 14 can be one of polyimide, acrylic and resin materials. Based on the leveling property of the second flat layer 14, if the depth difference h1 is too small, it is easy for the second flat layer 14 to fill and level, but it is not conducive to forming a curved surface; therefore, the depth difference is selected to be greater than or equal to 100 nanometers, so that the concave part ab of the second flat layer 14 is easy to form a concave curved surface.

[0090] Secondly, if the depth difference h1 is too large and the leveling property of the second flat layer 14 is weak, it will cause the second flat layer 14 to have a step difference. Therefore, the depth difference h1 between any two adjacent step sub-grooves a2 can be less than or equal to 200 nanometers.

[0091] Optionally, the depth difference h1 between any two adjacent step sub-grooves a2 may be 100 nanometers, 110 nanometers, 120 nanometers, 130 nanometers, 140 nanometers, 150 nanometers, 160 nanometers, 170 nanometers, 180 nanometers, 190 nanometers or 200 nanometers.

[0092] It is understandable that in the process of forming the first concave curved surface b1, the depth difference h1 and the leveling property of the second flat layer 14 play a key role, and different leveling properties can be matched with different depth differences h1 to form a suitable first concave curved surface b1. Therefore, according to different leveling properties, the value of the depth difference h1 may not be limited to the above range.

[0093] Optionally, in some embodiments of the present application, please refer to Figure 5 Based on a plane parallel to the surface of the substrate 11, the side wall of the opening 161 has a slope angle α, the tangent line of any point on the first concave arc surface b1 has a first inclination angle β, and the tangent line of any point on the second concave arc surface b2 has a second inclination angle θ.

[0094] In the direction from the side wall of the opening 161 to the center of the opening 161 , the first inclination angle β gradually decreases, the second inclination angle θ gradually decreases, and the maximum first inclination angle β and the maximum second inclination angle θ are both smaller than the slope angle α.

[0095] It should be understood that in the step of preparing the light-emitting functional layer, the hole injection layer, the hole transport layer and the light-emitting layer are printed by inkjet printing. When the hole injection layer material is dripped into the pixel opening, the hole injection layer accumulates at the edge of the pixel due to the capillary effect of the film layer.

[0096] The embodiment of the present application adopts a method of arranging a first concave arc surface b1 at the edge of the pixel to form an arc slope in coordination with the gravity effect to balance the capillary effect and reduce the risk of material accumulation. However, when the arc slope is too steep, the gravity effect is stronger than the capillary effect, which will cause the material on the upper part of the arc slope to become thinner and the material on the lower part to become thicker, resulting in uneven thickness of the hole injection layer.

[0097] Therefore, the second largest inclination angle θ in the second concave arc surface b2 is set to be smaller than the slope angle α to avoid the risk of the arc slope being too steep, thereby improving the film formation uniformity of the light-emitting functional layer 17 such as the hole injection layer HIL.

[0098] In addition, since the first electrode 15 is manufactured by sputtering process, the steepness of the second concave surface b2 depends on the morphology of the first concave surface b1. Therefore, the largest second inclination angle β of the first concave surface b1 is set smaller than the slope angle α to reduce the risk of the second concave surface b2 being too steep.

[0099] In some embodiments, the morphology of the second concave curved surface b2 can also be modified by other means without considering the morphology of the first concave curved surface b1, such as filling by inkjet printing, or reducing by dry etching, wet etching or laser etching.

[0100] Optionally, in some embodiments of the present application, the second concave curved surface b2 is connected to the side wall of the opening 161. In other words, the side wall of the opening 161 overlaps the second concave curved surface b2, so that the side wall of the opening 161 and the second concave curved surface b2 are connected to form a continuous inclined slope, reducing the risk of the light-emitting functional layer 17 being accumulated at the edge of the pixel.

[0101] based on Figure 2 The display panel 100 of the corresponding embodiment is prepared as follows:

[0102] Please refer to Figure 6 , step B01, forming a first planar material layer p1 on the substrate 11, and performing an exposure process on the first planar material layer p1 using a mask.

[0103] Optionally, the mask template mask includes multiple light-transmitting areas. The first light-transmitting area tg1 is a 100% light-transmitting area, which corresponds to the via hole. The second light-transmitting area tg2 is a stepped light-transmitting area, which corresponds to the groove ac. The second light-transmitting area tg2 includes multiple light-transmitting sub-areas z1. From the edge of the second light-transmitting area tg2 to the center, the transmittance of the light-transmitting sub-area z1 increases. That is, the transmittance of the light-transmitting sub-area z1 in the central area is the largest, and the transmittance of the light-transmitting sub-area z1 is less than 100%.

[0104] Optionally, the difference in transmittance between two adjacent light-transmitting sub-regions z1 is the same, for example, the difference in transmittance may be 5%, 10%, 15%, 20%, 25% or 30%.

[0105] It is understandable that the light transmittance determines the depth of the step sub-groove a2 and the base sub-groove a1. The same light transmittance difference can form the same depth difference h1 between the step sub-grooves a2.

[0106] Please refer to Figure 7 Step B02: developing the first planar material layer p1 to form a patterned first planar layer 13. At this time, the first planar layer 13 forms a groove ac.

[0107] Please refer to Figure 8 Step B03, forming a second flat layer 14 on the first flat layer 13. Based on the coating thickness, leveling property and film shrinkage of the second flat layer 14, the second flat layer 14 naturally forms a concave arc surface hm corresponding to the concave portion ab of the groove ac.

[0108] When the second flat material layer is applied, it is a wet film. After the second flat material layer is dried, the second flat layer 14 is formed, which is a dry film. The wet film thickness multiplied by the film shrinkage rate equals the dry film thickness.

[0109] Therefore, when the wet film fills the groove ac, the greater the thickness of the wet film is, the greater the shrinkage thickness thereof is. Due to the setting of the step depth difference, the second flat layer 14 can form a concave arc surface hm.

[0110] Optionally, the thickness of the second flat layer 14 is greater than the thickness of the first flat layer 13 , which can reduce the steepness of the first concave curved surface b1 and further reduce the steepness of the second concave curved surface b2 .

[0111] Please refer to Fig. 9 , step B04, forming a patterned first electrode 15 and a patterned pixel definition layer 16 in sequence on the second planar layer 14. The opening 161 of the pixel definition layer 16 exposes the first electrode 15. The sidewall of the opening 161 overlaps the second concave arc surface b2.

[0112] Please refer to Fig.10 , step B05 , forming a hole injection layer HIL, a hole transport layer HTL and a light emitting layer EML in the opening 161 , and then forming an electron transport layer ETL and a second electrode 18 on the pixel definition layer 16 .

[0113] Optionally, an inkjet printing process is used to drop hole injection layer materials, hole transport layer materials and light emitting layer materials into the opening 161. An evaporation process is used to form the electron transport layer ETL and the second electrode 18.

[0114] Fig.11 Another structural schematic diagram of the display panel 100 according to one or more embodiments of the present application is shown. Fig.12 It is shown that Fig.11 An enlarged schematic diagram of part B in FIG. Fig.11 and Fig.12 In the present invention, parts different from those of the above-described embodiment will be described to avoid redundancy.

[0115] Please refer to Fig.11 and Fig.12 In some embodiments of the present application, the surface of the concave portion ab away from the substrate 11 further includes a first flat surface pt1 located in the middle area, and the first flat surface pt1 is connected to the first concave arc surface b1.

[0116] A second flat surface pt2 is formed on a portion of the concave surface 15 a corresponding to the first flat surface pt1 , and the second flat surface pt2 is connected to the second concave arc surface b2 .

[0117] In the thickness direction of the display panel 100 , the first flat surface pt1 , the second flat surface pt2 , and the base sub-groove a1 are stacked.

[0118] Compared to Figure 2 The corresponding embodiment, Fig.11 In the corresponding embodiment, the middle area of ​​the surface of the concave portion ab of the display panel 100 and the middle area of ​​the surface of the first electrode 15 are both flat surfaces. The provision of the flat surface improves the uniformity of the film formation of the light emitting functional layer 17 .

[0119] Optionally, in some embodiments of the present application, the width k1 of the base sub-groove a1 is greater than the width k2 of the step sub-groove a2.

[0120] It is understandable that the larger the width k1 of the base sub-groove a1 is, the larger the first flat surface pt1 that can be formed is. Based on the depth difference h1 between the base sub-groove a1 and the step sub-groove a2, a concave arc surface is formed in the part of the base sub-groove a1 close to the step sub-groove a2. Therefore, the width k1 of the base sub-groove a1 is set larger to form a flat surface.

[0121] Optionally, the width k1 of the base sub-groove a1 is greater than twice the width k2 of the step sub-groove a2 , so as to form the first flat surface pt1 .

[0122] The display panel of the embodiment of the present application forms a stepped groove on the first flat layer, and utilizes the leveling and film shrinkage of the second flat layer so that the second flat layer is formed with a concave portion and the first electrode is formed with a concave surface. Based on the combination of the concave surface and the gravity effect, the climbing phenomenon of the material of the light-emitting functional layer is improved, and the risk of the material of the light-emitting functional layer accumulating at the bottom of the side wall of the opening is reduced.

[0123] Secondly, the display panel of the embodiment of the present application adopts the step-type groove of the first flat layer covered by the second flat layer, and the concave smoothness and size of the concave part can be flexibly adjusted by adjusting the number of steps, depth and width of the step sub-grooves of the groove, and the concave smoothness and size of the concave part can be further adjusted by adjusting the thickness and leveling property of the second flat layer to obtain a matching concave surface. That is, the concave part can be adjusted more flexibly and accurately.

[0124] In addition, based on the recess formed on the second flat layer, the first flat layer and the second flat layer can make up for the terrain step difference caused by the routing of the first electrode region, thereby reducing the impact on the film formation uniformity of the light-emitting functional layer.

[0125] The above is a detailed introduction to a display panel provided in an embodiment of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A display panel, characterized in that: include: substrate; a first flat layer, covering the substrate, the first flat layer being provided with a groove, the groove comprising a base sub-groove and a plurality of connected step sub-grooves, the plurality of step sub-grooves being located at the periphery of the base sub-groove, the depth of the base sub-groove being greater than the depth of the step sub-groove adjacent to the base sub-groove, and the depths of any two adjacent step sub-grooves increasing in a direction from the edge of the groove to the center of the groove; A second flat layer covering a side of the first flat layer away from the substrate, wherein the second flat layer includes a concave portion covering the groove; A first electrode is provided at least on a surface of the recessed portion away from the substrate, wherein a portion of the first electrode corresponding to the recessed portion is formed with a concave surface; a pixel definition layer, disposed on a side of the second planar layer away from the substrate, the pixel definition layer being provided with an opening including the first electrode; and The light-emitting functional layer is arranged in the opening and covers the first electrode.

2. The display panel according to claim 1, characterized in that: The surface of the recessed portion away from the substrate includes a first concave curved surface located in the edge area, and the first concave curved surface corresponds to the multiple steps of the step sub-grooves; a second concave curved surface is formed on the portion of the concave surface corresponding to the first concave curved surface, and in the thickness direction of the display panel, the first concave curved surface, the second concave curved surface and the multiple steps of the step sub-grooves are stacked.

3. The display panel according to claim 2, characterized in that: The surface of the concave portion away from the substrate further includes a first flat surface located in the middle area, and the first flat surface is connected to the first concave arc surface; A second flat surface is formed on the concave surface corresponding to the first flat surface, and the second flat surface is connected to the second concave arc surface; In the thickness direction of the display panel, the first flat surface, the second flat surface and the substrate sub-groove are stacked.

4. The display panel according to claim 3, characterized in that: The width of the base sub-groove is greater than the width of the step sub-groove.

5. The display panel according to claim 2, characterized in that: The surface of the concave portion away from the substrate further includes a third concave arc surface located in the middle area, the third concave arc surface is smoothly connected to the first concave arc surface, and the curvature of the third concave arc surface is less than or equal to the curvature of the first concave arc surface; A fourth concave arc surface is formed at a portion of the concave surface corresponding to the third concave arc surface, the fourth concave arc surface is smoothly connected to the second concave arc surface, and a curvature of the fourth concave arc surface is less than or equal to a curvature of the second concave arc surface; In the thickness direction of the display panel, the third concave curved surface, the fourth concave curved surface and the substrate sub-groove are stacked.

6. The display panel according to claim 5, characterized in that: The width of the base sub-groove is less than or equal to twice the width of the step sub-groove.

7. The display panel according to any one of claims 1 to 6, characterized in that: In a direction from the edge of the groove to the center of the groove, the widths of any two adjacent step sub-grooves are equal.

8. The display panel according to any one of claims 1 to 6, characterized in that: In the direction from the edge of the groove to the center of the groove, the depth difference between any two adjacent step sub-grooves is equal; Alternatively, in a direction from the edge of the groove to the center of the groove, the depth difference between two adjacent step sub-grooves decreases.

9. The display panel according to any one of claims 1 to 6, characterized in that: The depth difference between any two adjacent step sub-grooves is greater than or equal to 100 nanometers.

10. The display panel according to any one of claims 2 to 6, characterized in that: The first concave arc surface is a circular arc surface, and the second concave arc surface is a circular arc surface.

11. The display panel according to any one of claims 2 to 6, characterized in that: In a direction from the side wall of the opening toward the center of the opening, the curvature of the first concave arc surface decreases gradually, and the curvature of the second concave arc surface decreases gradually.

12. The display panel according to any one of claims 2 to 6, characterized in that: Based on a plane parallel to the substrate surface, the side wall of the opening has a slope angle, a tangent line at any point on the first concave arc surface has a first inclination angle, and a tangent line at any point on the second concave arc surface has a second inclination angle; In a direction from the side wall of the opening to the center of the opening, the first inclination angle gradually decreases, the second inclination angle gradually decreases, and the maximum first inclination angle and the maximum second inclination angle are both smaller than the slope angle.

13. The display panel according to any one of claims 2 to 6, characterized in that: The second concave arc surface is connected to the side wall of the opening.

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