Display panel

Abstract

The display panel disclosed by the embodiments of the present application forms a stepped groove on the first planar layer, the depth of any two adjacent stepped sub-grooves increases in the direction from the edge of the groove to the center of the groove, so that the second planar layer forms a recess and the first electrode forms a concave surface. Based on the combination of the concave surface and the gravity effect, the risk of accumulation of the material of the light-emitting functional layer near the bottom of the sidewall of the opening is reduced. The display panel of the embodiments of the present application covers the stepped groove of the first planar layer by the second planar layer, the number of steps, the depth and the width of the stepped sub-groove of the groove can be adjusted to flexibly adjust the smoothness and size of the recess, and the thickness and the flow flatness of the second planar layer can be adjusted to further adjust the smoothness and size of the recess to obtain a matching concave surface.

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 current mainstream printed organic light-emitting diode panel's light-emitting layer materials are prone to coffee ring effect, which causes the hole injection layer c1, hole transport layer c2 and light-emitting layer c3 to climb and accumulate at the opening edge of the pixel definition layer c4. Figure 1 As shown, this affects the film morphology of the light-emitting layer, causing the thickness ratio of the film layer at the edge of the pixel to change, affecting 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 around 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 depth of any two adjacent step sub-grooves increasing from the edge of the groove toward the center of the groove;

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

[0008] a first electrode, at least provided 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 disposed 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; the portion of the concave surface corresponding to the first concave arc surface is formed with a second 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 recess away from the surface of the substrate further comprises a first flat surface in the middle region, the first flat surface being connected to the first concave curved surface;

[0013] The concave surface corresponding to the part of the first flat surface is formed with a second flat surface, the second flat surface being connected to the second concave curved surface;

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

[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 recess away from the surface of the substrate further comprises a third concave curved surface in the middle region, the third concave curved surface being smoothly connected to the first concave curved surface, the curvature of the third concave curved surface being less than or equal to the curvature of the first concave curved surface;

[0017] The concave surface corresponding to the part of the third concave curved surface is formed with a fourth concave curved surface, the fourth concave curved surface being smoothly connected to the second concave curved surface, the curvature of the fourth concave curved surface being less than or equal to the curvature of the second concave curved surface;

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

[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 recess to the center of the recess, the width of any two adjacent levels of the step sub-groove is equal.

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

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

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

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

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

[0026] Optionally, in some embodiments of the present application, based on a plane parallel to the substrate plate surface, the side wall of the opening has a slope angle, a tangent of any point on the first concave surface has a first inclination angle, and a tangent of any point on the second concave surface has a second inclination angle.

[0027] The first inclination angle gradually decreases from the side wall of the opening to the center of the opening, the second inclination angle gradually decreases from the side wall of the opening to the center of the opening, 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 surface connects the side wall of the opening.

[0029] The display panel of the embodiments of the present application forms a stepped groove on the first flat layer, and utilizes the flow leveling property and film shrinkage of the second flat layer to make the second flat layer form a recess and the first electrode form 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 accumulation of the material of the light-emitting functional layer near the bottom of the side wall of the opening is reduced.

[0030] Secondly, the display panel of the embodiments of the present application adopts the mode that the second flat layer covers the stepped groove of the first flat layer, the size and the recess smoothness of the recess can be flexibly adjusted by adjusting the number, the depth and the width of the stepped sub-grooves of the groove, and the size and the recess smoothness of the recess can be further adjusted by adjusting the thickness and the flow leveling property of the second flat layer to obtain a matching concave surface. That is, the recess and the concave surface of the first electrode can be more flexibly and more accurately adjusted.

[0031] In addition, based on the fact that the recess is formed on the second flat layer, the first flat layer and the second flat layer can compensate for the terrain difference caused by the wiring in the first electrode area, and reduce the influence on the film forming uniformity of the light-emitting functional layer. BRIEF DESCRIPTION OF DRAWINGS

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

[0033] Figure 2 is a structural schematic diagram of a display panel provided by the embodiments of the present application;

[0034] Figure 3 is Figure 2 is an enlarged schematic diagram of part A in FIG. 8;

[0035] Figure 4 is a structural schematic diagram of a first planar layer and a second planar layer of a display panel provided by an embodiment of the present application;

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

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

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

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

[0040] Figure 9 is a schematic diagram of step B04 of a preparation method of a display panel provided by an embodiment of the present application;

[0041] Figure 10 is a schematic diagram of step B05 of a preparation method of a display panel provided by an embodiment of the present application;

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

[0043] Figure 12 is Figure 11 is an enlarged schematic diagram of part B. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. In addition, it should be understood that the specific implementation described herein is only used to illustrate and explain the present application, and is not used to limit the present application. In the present application, the embodiments can be combined with each other but are not described one by one, and the positional words such as “up” and “down” are generally used to refer to the up and down of the device in the actual use or working state, and the specific is the direction of the drawing surface in the drawings; and “inner” and “outer” are used in relation to the outline of the device; the words “first”, “second”, “third” and the like are only used as labels, and do not impose numerical requirements or establish sequences.

[0045] Embodiments of the present application provide 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 Embodiments of the present application provide a display panel 100, which includes a substrate 11, a driving circuit layer 12, a first planar layer 13, a second planar 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 disposed 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 dual-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 embodiments of the present application, the structure of the thin film transistor tft is not specifically limited.

[0049] In Figure 2 and Figure 3 , 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 sequentially stacked. The first planar layer 13 covers one side of the fifth insulating layer 12f away from the substrate 11.

[0050] Optionally, in one or more embodiments, the display panel 100 can 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 planar layer 13 is disposed on the substrate 11. The first planar layer 13 has a recess ac formed therein. The recess ac includes a base sub-groove a1 and a plurality of stepped sub-grooves a2 in communication with each other, and the plurality of stepped sub-grooves a2 are located on the circumferential side of the base sub-groove a1. The depth of the base sub-groove a1 is greater than the depth of the stepped sub-groove a2 adjacent to the base sub-groove a1. In a direction from the edge of the recess ac to the center of the recess ac, the depth of any two adjacent stepped sub-grooves a2 increases.

[0052] The second planar layer 14 is disposed on a side of the first planar layer 13 away from the substrate 11. The second planar layer 14 includes a recess ab covering the recess ac.

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

[0054] The pixel definition layer 16 is disposed on the 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 the 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 only includes a 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 can further 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 described as an example, but is not limited thereto. Figure 2

[0059] In 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. Figure 2 Figure 3 Optionally, the first electrode 15 can be a single film layer, or a stacked structure of multiple film layers, such as ITO / Ag / ITO.

[0060] It can be understood that the display panel 100 of the embodiment of the present application forms a stepped groove ac on the first planar layer 13, and utilizes the flow leveling property and film shrinkage of the second planar layer 14, so that the second planar layer 14 forms a recess 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 layers 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 accumulation of the material of the light-emitting functional layer 17 near the bottom of the sidewall of the opening 161 is reduced.

[0061]

[0062] ​​​Secondly, the step-shaped groove ac can be formed by using a mask plate for patterning the first planar layer 13, without additional processes. The display panel 100 in the embodiment of the present application covers the step-shaped groove ac of the first planar layer 13 by the second planar layer 14, which can flexibly adjust the concave smoothness and size of the recess ab by adjusting the number, depth and width of the step sub-grooves a2, and further adjust the concave smoothness of the recess ab by adjusting the thickness and flow flatness of the second planar layer 14, to obtain a matching concave surface 15a. That is, the recess ab can be more flexibly and accurately adjusted.

[0063] In addition, the recess ab is formed on the second planar layer 14, so that the first planar layer 13 and the second planar layer 14 can compensate for the terrain difference caused by the wiring in the first electrode 15 area, and reduce the influence on the film uniformity of the light-emitting functional layer 17.

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

[0065] It can be understood that the display panel 100 in the embodiment of the present application forms a step-shaped groove ac on the first planar layer 13, and utilizes the flow flatness and film shrinkage of the second planar layer 14, so that the recess ab of the second planar layer 14 is formed with the first concave arc surface b1, and the first electrode 15 is formed with the 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 accumulation of the material of the light-emitting functional layer 17 near the bottom of the sidewall of the opening 161 is reduced.

[0066] Secondly, the display panel 100 in the embodiment of the present application covers the step-shaped groove ac of the first planar layer 13 by the second planar layer 14, which can flexibly adjust the bending degree and size of the first concave arc surface b1 by adjusting the number, depth and width of the step sub-grooves a2, and further adjust the bending degree and size of the first concave arc surface b1 by adjusting the thickness and flow flatness of the second planar layer 14, to obtain a matching second concave arc surface b2. That is, the first concave arc surface b1 can be more flexibly and accurately adjusted.

[0067] In addition, since the first concave surface b1 is 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 .

[0068] It should be noted that, in some embodiments, the first concave arc surface b1 can also be replaced by a multi-level first step surface, and the second concave arc surface b2 can also be replaced by a multi-level second step surface, 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 recessed portion ab away from the substrate 11 further includes a third concave curved surface b3 located in the middle region, the third concave curved surface b3 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 surface b3 forms a fourth concave surface b4, which is smoothly connected to the second concave surface b2 and has a curvature less than or equal to that of the second concave 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 base 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 arc surface b1 and the third concave arc surface b3 can each be one of a circular arc surface and a curved surface with a gradually changing curvature. The second concave arc surface b2 and the first concave arc surface b1 are of the same type, and the fourth concave arc surface b4 and the third concave arc surface b3 are of the same type.

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

[0076] However, the display panel 100 of the embodiment of the present application 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, please refer to 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 base 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 base width surrounding the entire circumference. The larger the width k1 of the base sub-groove a1, the flatter the corresponding third concave curved surface b3 at a certain distance from the first concave curved surface b1, until it approaches a horizontal state. 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 curved surface b3 is an overall curved surface.

[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, 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 a 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, the depth difference h1 between any two adjacent step sub-grooves a2 in the direction from the edge of the groove ac to the center of the groove ac is equal.

[0083] It is understood that the combination of the depth difference h1 between any two adjacent step sub-grooves a2 and the width k2 of the step sub-grooves a2 determines the curvature and dimensions of the first concave arc surface b1. Therefore, if the depth difference h1 between any two adjacent step sub-grooves a2 is equal, the curvature of the first concave arc surface b1 will be uniform, resulting in a smoother continuity. For example, if the width k2 of any two adjacent step sub-grooves a2 is equal and the depth difference h1 between any two adjacent step sub-grooves a2 is equal, the first concave arc surface b1 can form a circular arc.

[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 smoother towards the center, so that the curvature of the first concave arc surface b1 in the area closer to the center of the groove ac becomes smoother, which facilitates 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, the curvature of the first concave arc surface b1 decreases gradually from the sidewall of the opening 161 toward the center of the opening 161 , 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 understood that the materials of the first and second planarizing layers 13 and 14 can each be selected from polyimide, acrylic, and resin-based materials. Due to the leveling properties of the second planarizing layer 14, if the depth difference h1 is too small, the second planarizing layer 14 will tend to fill the surface, hindering the formation of a curved surface. Therefore, a depth difference of 100 nanometers or greater is selected to facilitate the formation of a concave curved surface in the concave portion ab of the second planarizing layer 14.

[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 step differences in the second flat layer 14 . Therefore, the depth difference h1 between any two adjacent step sub-grooves a2 can be less than or equal to 200 nm.

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

[0092] It is understood that the depth difference h1 and the leveling properties of the second flat layer 14 play a critical role in forming the first concave curved surface b1. Different leveling properties can be combined with different depth differences h1 to form a suitable first concave curved surface b1. Therefore, depending on the leveling properties, the value of the depth difference h1 may not be limited to the above range.

[0093] Optionally, in some embodiments of this 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] From the sidewall of the opening 161 toward the center of the opening 161 , the first inclination angle β gradually decreases, and 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 during the preparation of the light-emitting functional layer, the hole injection layer, hole transport layer, and light-emitting layer are inkjet printed. When the hole injection layer material is dripped into the pixel opening, the capillary effect of the film layer causes the hole injection layer to accumulate at the edge of the pixel.

[0096] The present embodiment employs a method of providing a first concave curved surface b1 at the pixel edge to form a curved slope that cooperates with gravity to balance the capillary effect and reduce the risk of material accumulation. However, if the curved slope is too steep, gravity will outweigh the capillary effect, causing the material to become thinner at the upper portion of the slope and thicker at the lower portion, resulting in uneven hole injection layer thickness.

[0097] Therefore, the second largest inclination angle θ of the second concave 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] Furthermore, since the first electrode 15 is formed using a sputtering process, the steepness of the second concave surface b2 depends on the topography of the first concave surface b1. Therefore, the maximum second inclination angle β of the first concave surface b1 is set to be 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 surface b2 can also be modified by other means without considering the morphology of the first concave 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 sidewall of the opening 161. In other words, the sidewall of the opening 161 overlaps the second concave curved surface b2, so that the sidewall of the opening 161 and the second concave curved surface b2 are connected to form a continuous slope, reducing the risk of the light-emitting functional layer 17 accumulating 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 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. The transmittance of the light-transmitting sub-areas z1 increases from the edge to the center of the second light-transmitting area tg2. That is, the transmittance of the light-transmitting sub-area z1 in the central area is the highest, 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 understood 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 In step B02, the first planar material layer p1 is developed 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 In step B03, a second flat layer 14 is formed on the first flat layer 13. Based on the coating thickness, leveling properties, 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] Wherein, when the second planar material layer is coated, it is a wet film. After the second planar material layer is dried, the second planar layer 14 is formed, which is a dry film. The wet film thickness multiplied by the film shrinkage equals the dry film thickness.

[0109] Therefore, when the wet film fills the groove ac, the greater the thickness of the wet film, the more the thickness of the wet film shrinks. By setting the difference in step depth, the second planar layer 14 forms a concave arc hm.

[0110] Optionally, the thickness of the second planar layer 14 is greater than the thickness of the first planar layer 13, which can slow down the steepness of the first concave arc b1, and further slow down the steepness of the second concave arc b2.

[0111] Please refer to Figure 9 , step B04, a patterned first electrode 15 and a patterned pixel definition layer 16 are sequentially formed 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 is overlapped on the second concave arc b2.

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

[0113] Optionally, the hole injection layer material, the hole transport layer material and the light emitting layer material are dripped into the opening 161 by using an inkjet printing process. The electron transport layer ETL and the second electrode 18 are formed by using an evaporation process.

[0114] Figure 11 Another structural schematic diagram of the display panel 100 of one or more embodiments of the present application is shown. Figure 12 What is shown is Figure 11 an enlarged schematic diagram of part B. In Figure 11 and Figure 12 , the parts different from the parts of the above-mentioned embodiments will be described to avoid redundancy.

[0115] Please refer to Figure 11 and Figure 12 , in some embodiments of the present application, the recess ab away from the surface of the substrate 11 further comprises a first planar surface pt1 located in the middle region, and the first planar surface pt1 is connected to the first concave arc b1.

[0116] The concave surface 15a corresponding to the part of the first planar surface pt1 is formed with a second planar surface pt2, and the second planar surface pt2 is connected to the second concave arc b2.

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

[0118] Compared to Figure 2 The corresponding embodiment, Figure 11 In the corresponding embodiment, the middle area of ​​the surface of the display panel 100 where the concave portion ab is provided and the middle area of ​​the surface of the first electrode 15 are both flat surfaces. The provision of the flat surface improves the film formation uniformity 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 understood that the larger the width k1 of the base sub-groove a1, the larger the first flat surface pt1 that can be formed. Due to the depth difference h1 between the base sub-groove a1 and the step sub-groove a2, the portion of the base sub-groove a1 near the step sub-groove a2 forms a concave arc. 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 present invention employs a stepped groove formed on the first planar layer. The second planar layer's leveling and shrinkage properties are leveraged to create a concave portion in the second planar layer and a concave surface in the first electrode. This concave surface, combined with the gravity effect, improves the slope of the light-emitting functional layer material, reducing the risk of accumulation of light-emitting functional layer material at the bottom of the sidewalls of the opening.

[0123] Secondly, the display panel of the present embodiment uses a second flat layer covering the stepped groove of the first flat layer. The number, depth, and width of the stepped sub-grooves in the groove can be adjusted to flexibly adjust the smoothness and size of the concave portion. Furthermore, the thickness and leveling properties of the second flat layer can be adjusted to further adjust the smoothness and size of the concave portion to obtain a matching concave surface. This allows for more flexible and precise adjustment of the concave portion.

[0124] In addition, since the recess is formed on the second flat layer, the first flat layer and the second flat layer can compensate for the topographic 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 those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods 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 around 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 depth of any two adjacent step sub-grooves increasing from the edge of the groove toward the center of the groove; a second flat layer covering a side of the first flat layer away from the substrate, the second flat layer comprising a concave portion covering the groove; a first electrode, at least provided 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 disposed in the opening and covers the first electrode.

2. The display panel according to claim 1, wherein: 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 steps 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 steps of the step sub-grooves are stacked.

3. The display panel according to claim 2, wherein: 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 portion of 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 base sub-groove are stacked.

4. The display panel according to claim 3, wherein: 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, wherein: 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 on 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 the curvature of the fourth concave arc surface is less than or equal to the 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, wherein: 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, wherein: 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, wherein: 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, the depth difference between two adjacent step sub-grooves decreases in a direction from the edge of the groove to the center of the groove.

9. The display panel according to any one of claims 1 to 6, wherein: 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, wherein: 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, wherein: 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 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; In a direction from the side wall of the opening toward 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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