Display panel and preparation method therefor, display device, and tiled display device

Abstract

A display panel and a preparation method therefor, a display device, and a tiled display device. The display panel comprises a substrate, a circuit board, a cushion pad layer, a plurality of back electrodes and a plurality of connecting leads. The substrate comprises a first surface, a second surface, and at least one selected first side surface. The circuit board comprises a third surface, a fourth surface, and at least one selected second side surface. The cushion pad layer at least further covers the boundary between the fourth surface and the selected second side surface of the circuit board. The plurality of back electrodes are arranged on the fourth surface in parallel at intervals. A third part of each connecting lead is electrically connected to one back electrode, and said third part comprises a part located on the cushion pad layer. The ratio of the maximum value of the line width of said third part to the minimum value of the line width of said third part falls within the range of 1.0-1.5. The display panel is used for displaying images.

Description

Display panel, preparation method thereof, display device and spliced display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular to a display panel, a preparation method thereof, a display device and a spliced display device. BACKGROUND

[0002] Micro LED (Micro Light Emitting Diode) and Mini LED (Mini Light Emitting Diode Display) are smaller in size than traditional LEDs, and are widely used in display devices to form Micro LED / Mini LED display devices, which have high display effects.

[0003] SUMMARY

[0004] In one aspect, a display panel is provided. The display panel includes a substrate, a circuit board, a buffer pad layer, a plurality of back electrodes, and a plurality of connecting leads. The substrate includes a first surface and a second surface disposed opposite to each other, and a plurality of first side surfaces connecting the first surface and the second surface; the plurality of first side surfaces includes at least one selected first side surface. The circuit board is disposed on the second surface; the circuit board includes a third surface and a fourth surface disposed opposite to each other, and a plurality of second side surfaces connecting the third surface and the fourth surface; the third surface is closer to the substrate than the fourth surface; the plurality of second side surfaces includes at least one selected second side surface; each selected second side surface corresponds to one selected first side surface. The buffer pad layer is located on a side of the circuit board closer to the selected first side surface, and at least covers an intersection of the fourth surface and the selected second side surface of the circuit board. The plurality of back electrodes are arranged in parallel and spaced apart on the fourth surface. The plurality of connecting leads are arranged in parallel and spaced apart; each connecting lead includes a first portion located on a side of the first surface, a second portion located on a side of the selected first side surface, and a third portion located on a side of the second surface; the third portion of each connecting lead is electrically connected to one back electrode; the third portion of the connecting lead includes a portion located on the buffer pad layer. The ratio between the maximum value of the line width of the third portion of the connecting lead and the minimum value of the line width of the third portion of the connecting lead is in the range of 1.0-1.5, and the line width of the third portion of the connecting lead is the dimension of the third portion of the connecting lead in a direction perpendicular to the extension direction of the third portion of the connecting lead.

[0005] In some embodiments, the buffer pad layer comprises a first boundary and a second boundary, the first boundary and the second boundary are arranged along a first direction in the orthographic projection of the second surface. The first boundary is farther away from the back electrode than the second boundary in the first direction. The first direction is the extension direction of the third part of the connecting lead. The third part of the connecting lead comprises a first position, the first position is located on the side of the first boundary away from the second boundary, and the distance between the first position and the first boundary in the first direction is in the range of 50 μm to 200 μm; the line width of the third part of the connecting lead gradually increases from the first position to the first boundary.

[0006] In some embodiments, the line width of the third part of the connecting lead reaches a first maximum line width at a second position. The second position is located between the first boundary and the second boundary. The distance between the second position and the first boundary in the first direction is in the range of 0 to 600 μm.

[0007] In some embodiments, the ratio between the first maximum line width and the line width of the third part of the connecting lead at the first position is in the range of 1.0 to 1.5.

[0008] In some embodiments, the intersection of the selected first side surface and the second surface is a first reference edge. The cross section of the buffer pad layer perpendicular to the first reference edge is a second cross section. In the second cross section, the distance between the surface of the buffer pad layer away from the second surface and the second surface of the substrate gradually increases from the first boundary to a third position and gradually decreases from the third position to the second boundary; the third position is located between the second position and the second boundary. The line width of the third part of the connecting lead reaches a minimum line width at a fourth position, the fourth position is located between the third position and the second boundary, and the distance between the fourth position and the second boundary in the first direction is in the range of 0 to 400 μm.

[0009] In some embodiments, the ratio between the minimum line width and the line width of the third part of the connecting lead at the first position is in the range of 1.0 to 1.5.

[0010] In some embodiments, the line width of the third part of the connecting lead reaches a second maximum line width at a fifth position. The fifth position is located on the side of the second boundary away from the first boundary. The distance between the fifth position and the second boundary in the first direction is in the range of 0 to 150 μm.

[0011] In some embodiments, when the line width of the third part of the connecting lead reaches a first maximum line width at the second position, the second maximum line width is less than or equal to the first maximum line width.

[0012] In some embodiments, the ratio between the second maximum line width and the line width of the third part of the connecting lead at the first position is in the range of 1.0 to 1.5.

[0013] In some embodiments, the third portion of the connecting lead further comprises a sixth position. The sixth position is located on a side of the fifth position away from the second boundary. The sixth position is located at a distance from the second boundary in the first direction in a range from 50 μm to 200 μm. The line width of the third portion of the connecting lead gradually decreases from the fifth position to the sixth position.

[0014] In some embodiments, the first boundary is located on the second surface. The line width of the third portion of the connecting lead reaches a third maximum line width at a seventh position. The seventh position is located on the second surface and is located at a distance from the selected first side surface in a range from 50 μm to 150 μm.

[0015] In some embodiments, in the case that the line width of the third portion of the connecting lead reaches a first maximum line width at the second position, the third maximum line width is less than or equal to the first maximum line width.

[0016] In some embodiments, a ratio between the third maximum line width and the line width of the third portion of the connecting lead at the first position is in a range from 1.0 to 1.5.

[0017] In some embodiments, an intersection between the selected first side surface and the second surface is a first reference edge. A surface of the buffer pad layer away from the second surface of the substrate is a fifth surface. A cross section of the fifth surface perpendicular to the first reference edge is a first line segment. The first line segment is a curved segment. An angle between a tangent of the first line segment and the second surface is in a range from 0° to 40°.

[0018] In some embodiments, the first boundary is located on the selected first side surface. A dimension of a portion of the selected first side surface covered by the buffer pad layer in a direction perpendicular to the first reference edge is in a range from 0 μm to 30 μm. The first reference edge is an intersection between the selected first side surface and the second surface.

[0019] In some embodiments, the selected first side surface comprises a first sub-surface, a second sub-surface, and a third sub-surface. The first sub-surface is parallel to the first reference edge and perpendicular to the first surface, the first reference edge being an intersection between the selected first side surface and the second surface. The second sub-surface is located between the first sub-surface and the first surface and is inclined. The third sub-surface is located between the first sub-surface and the second surface and is inclined. An angle between the second sub-surface and the first surface is in a range from 110° to 160°; and / or, an angle between the third sub-surface and the second surface is in a range from 110° to 160°.

[0020] In some embodiments, the display panel further comprises a plurality of front electrodes. The plurality of front electrodes are arranged in parallel on the first surface. Each front electrode corresponds to one back electrode. The first boundary is located on a side of the first surface and contacts the plurality of front electrodes.

[0021] In some embodiments, the back electrode includes a sixth surface and a seventh surface disposed opposite to each other, and a plurality of third side surfaces connecting the sixth surface and the seventh surface. The sixth surface is closer to the circuit board than the seventh surface. The plurality of third side surfaces includes a selected third side surface. The selected third side surface corresponds to a selected second side surface. The corresponding selected second side surface and the selected third side surface are flush. The selected second side surface and the selected third side surface are located on a side of the first reference edge away from the second surface. An angle between the third sub-surface and the second surface is smaller than or equal to an angle between the second sub-surface and the first surface. The material of the cushion layer is embedded in a region between the third sub-surface and the third surface.

[0022] In some embodiments, the back electrode includes a sixth surface and a seventh surface disposed opposite to each other, and a plurality of third side surfaces connecting the sixth surface and the seventh surface. The sixth surface is closer to the circuit board than the seventh surface. The plurality of third side surfaces includes a selected third side surface. The selected third side surface corresponds to a selected second side surface. The cushion layer also covers an interface between the seventh surface of the back electrode and the selected third side surface. A portion of the cushion layer located on a side of the seventh surface has a dimension in the first direction ranging from 0 to 200 μm. The first direction is an extension direction of the third portion of the lead.

[0023] In some embodiments, the back electrode includes a sixth surface and a seventh surface disposed opposite to each other, and a plurality of third side surfaces connecting the sixth surface and the seventh surface. The sixth surface is closer to the circuit board than the seventh surface. The plurality of third side surfaces includes a selected third side surface. The selected third side surface corresponds to a selected second side surface. A second boundary is located on the fourth surface and between the selected third side surface and the selected second side surface. The second boundary and the selected third side surface have a distance in the first direction ranging from 50 μm to 250 μm. The first direction is an extension direction of the third portion of the lead.

[0024] In some embodiments, the intersection line of the selected first side surface and the second surface is the first reference edge. A surface of the cushion layer away from the second surface of the substrate is a fifth surface. A cross section of the fifth surface perpendicular to the first reference edge is a first line segment. The first line segment has a dimension ranging from 300 μm to 1000 μm.

[0025] In some embodiments, in a portion of the fourth surface close to the selected second side surface, in a direction of the selected second side surface pointing to the selected first side surface, the distance between the fourth surface and the second surface gradually decreases.

[0026] In some embodiments, the circuit board includes an adhesive layer and a carrier body stacked. The adhesive layer is closer to the substrate than the carrier body. The distance between the carrier body and the selected first side surface in the first direction is smaller than the distance between the adhesive layer and the selected first side surface in the first direction. The first direction is an extension direction of the third portion of the lead.

[0027] In some embodiments, the distance between the selected first side surface and the carrier substrate body in the first direction is less than or equal to 80 pm.

[0028] In some embodiments, the intersection between the selected first side surface and the second surface is a first reference edge. A cross section of the fourth surface perpendicular to the first reference edge is a second line segment. An included angle between a tangent of the second line segment and the second surface ranges from 0° to 15°.

[0029] In another aspect, a method for manufacturing a display panel is provided. The method includes providing a substrate; the substrate includes a first surface and a second surface arranged oppositely, and a plurality of first side surfaces connecting the first surface and the second surface; the plurality of first side surfaces includes at least one selected first side surface. Forming a circuit board on the second surface; the circuit board includes a third surface and a fourth surface arranged oppositely, and a plurality of second side surfaces connecting the third surface and the fourth surface; the third surface is closer to the substrate than the fourth surface; the plurality of second side surfaces includes at least one selected second side surface; each selected second side surface corresponds to one selected first side surface. Forming a plurality of back electrodes on the fourth surface; the plurality of back electrodes are arranged side by side and spaced apart on the fourth surface. Forming a buffer pad layer on a side of the circuit board closer to the selected first side surface; the buffer pad layer at least covers the intersection between the fourth surface of the circuit board and the selected second side surface. Forming a plurality of connection leads; the plurality of connection leads are arranged side by side and spaced apart; each connection lead includes a first portion on the first surface side, a second portion on the selected first side surface side, and a third portion on the second surface side; the third portion of each connection lead is electrically connected to one back electrode; the third portion of the connection lead includes a portion on the buffer pad layer. A ratio between a maximum value of the line width of the third portion of the connection lead and a minimum value of the line width of the third portion of the connection lead ranges from 1 to 1.5, and the line width of the third portion of the connection lead is a dimension of the third portion of the connection lead in a direction perpendicular to the extension direction of the third portion of the connection lead.

[0030] In yet another aspect, a display device is provided. The display device includes a driving circuit board and a display panel as described in any of the above embodiments. The driving circuit board is electrically connected to the display panel, and is configured to drive the display panel to display an image.

[0031] In still another aspect, a tiled display device is provided. The display device includes a plurality of display devices as described in any of the above embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the present disclosure, the following will briefly introduce the drawings needed to be used in some embodiments of the present disclosure. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not limited to the actual size, actual process, actual timing of signals, etc. of the products involved in the embodiments of the present disclosure.

[0033] FIG. 1 is a structural diagram of a display panel according to some embodiments;

[0034] FIG. 2 is a structural diagram of a display panel according to some other embodiments;

[0035] FIG. 3 is a partial enlarged view of J in FIG. 2;

[0036] FIG. 4 is a structural diagram of a display panel according to some other embodiments;

[0037] FIG. 5 is a structural diagram of a substrate according to some other embodiments;

[0038] FIG. 6 is a partial enlarged view of C2 in FIG. 5;

[0039] FIG. 7 is a positional relationship diagram of an initial substrate and a grinding rod according to some embodiments;

[0040] FIG. 8 is a partial enlarged view of C1 in FIG. 7;

[0041] FIG. 9 is a structural diagram of a substrate according to some other embodiments;

[0042] FIG. 10 is a structural diagram of a display panel according to some other embodiments;

[0043] FIG. 11 is a flowchart of a preparation process of a display panel according to some embodiments;

[0044] FIG. 12 is a structural diagram of a display panel according to some other embodiments;

[0045] FIG. 13 is a partial cross-sectional view along line A-A in FIG. 12;

[0046] FIG. 14 is a structural diagram of a display panel according to some other embodiments;

[0047] FIG. 15 is a partial cross-sectional view along line B-B in FIG. 14;

[0048] FIG. 16 is a structural diagram of a display panel according to some other embodiments;

[0049] FIG. 17 is a structural diagram of a display panel according to some other embodiments;

[0050] FIG. 18 is a structural diagram of a display panel according to some embodiments;

[0051] FIG. 19 is a structural diagram of a display panel according to some embodiments;

[0052] FIG. 20 is a partial enlarged view of U in FIG. 19;

[0053] FIG. 21 is a structural diagram of a display panel according to some embodiments;

[0054] FIG. 22 is a structural diagram of a display panel according to some embodiments;

[0055] FIG. 23 is a structural diagram of a display panel according to some embodiments;

[0056] FIG. 24 is a structural diagram of a display panel according to some embodiments;

[0057] FIG. 25 is a step diagram of a method for manufacturing a display panel according to some embodiments;

[0058] FIG. 26 is a diagram for dividing an initial section, a middle section and a final section of a connecting lead according to some embodiments;

[0059] FIG. 27 is a topography diagram of a connecting lead according to some embodiments;

[0060] FIG. 28 is a diagram of the variation of the line width of the initial section, the middle section and the final section of a connecting lead and the cross-sectional area of the connecting lead with the needle-to-surface distance according to some embodiments;

[0061] FIG. 29 is a topography diagram of a connecting lead according to some embodiments;

[0062] FIG. 30 is a topography diagram of a connecting lead according to some embodiments;

[0063] FIG. 31 is a structural diagram of a display panel according to some embodiments;

[0064] FIG. 32 is a step diagram of a method for manufacturing a display panel according to some embodiments;

[0065] FIG. 33 is a step diagram of forming a buffer pad layer according to some embodiments;

[0066] FIG. 34 is a step diagram of forming a buffer pad layer according to some embodiments;

[0067] FIG. 35 is a structural diagram of a display panel according to some embodiments;

[0068] FIG. 36 is a structural diagram of a display panel according to some embodiments;

[0069] FIG. 37 is a structural diagram of a display panel according to some embodiments;

[0070] FIG. 38 is a structural diagram of a display panel according to still other embodiments;

[0071] FIG. 39A is a structural diagram of a display device according to some embodiments;

[0072] FIG. 39B is a structural diagram of a display device according to yet other embodiments;

[0073] FIG. 40 is a structural diagram of a display panel according to yet other embodiments;

[0074] FIG. 41 is a structural diagram of a tiled display device according to some embodiments;

[0075] FIG. 42 is a structural diagram of a display panel according to yet other embodiments;

[0076] FIG. 43 is a structural diagram of a tiled display device according to still other embodiments. DETAILED DESCRIPTION

[0077] The technical solutions in some embodiments of the present disclosure will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments provided in the present disclosure, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present disclosure.

[0078] Unless otherwise required by context, the term “comprise” and other forms of the term “comprise”, such as “comprises” and “comprising”, are to be construed as open, inclusive, meaning, i.e., “including, but not limited to”, in the entire specification and claims. In the description of the specification, the terms “one embodiment”, “some embodiments”, “exemplary embodiments”, “example”, “specific example” or “some examples” are intended to mean that the particular feature, structure, material or characteristic associated with that embodiment or example is included in at least one embodiment or example of the present disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. In addition, the particular features, structures, materials or characteristics described can be included in any suitable manner in any one or more embodiments or examples.

[0079] The terms "first", "second", etc. are used herein only to describe one implementation, and do not imply either an actual order or relative importance of the described features. Thus, a feature defined with "first", "second", etc. can include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise stated, the meaning of "a plurality" is two or more.

[0080] In describing some embodiments, "coupled" and "connected", and variations thereof, can be used. For example, these terms can be used to indicate that two or more components are in direct physical or electrical contact with each other. As used herein, coupled or connected can also mean that two or more components are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments disclosed herein are not necessarily limited in scope to the terms used herein.

[0081] "A and / or B" includes the following three combinations: A alone, B alone, and a combination of A and B.

[0082] The use of "adapted to" or "configured to" herein means open and inclusive language that does not exclude additional devices or steps not explicitly described.

[0083] As used herein, "parallel", "perpendicular", "equal" include the recited condition and conditions that are approximately the recited condition, within an acceptable range of deviation, as determined by one of ordinary skill in the art considering the measurements at issue and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallel and approximately parallel, where approximately parallel can be within an acceptable range of deviation of, for example, 5°; "perpendicular" includes absolute perpendicular and approximately perpendicular, where approximately perpendicular can also be within an acceptable range of deviation of, for example, 5°. "Equal" includes absolute equality and approximate equality, where approximately equal can be within an acceptable range of deviation of, for example, less than or equal to 5% of either of the two quantities being compared.

[0084] It should be understood that when a layer or element is referred to as being "on" another layer or substrate, it can be directly on the other layer or substrate, or intervening layers can also be present.

[0085] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are schematic illustrations of idealized embodiments. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region illustrated as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic and their shapes are not intended to illustrate the precise shape of a region that would be formed in a device and are not intended to limit the scope of the exemplary embodiments.

[0086] It should be noted that, in the drawings of the present disclosure, for example, 11-1 indicates that the component 11 belongs to the component 1, for example, 1b-1 indicates that the second surface 1b belongs to the substrate 1, and other similar notations appearing in the drawings also follow the above description. For example, 1 / 2 appearing in the drawings of the present disclosure indicates that the component 1 and the component 2 can both refer to the component, for example, 511 / 51 appearing in the drawings indicates that the selected first light emitting device 511 and the light emitting device 51 can both be represented by the component. Other similar notations appearing in the drawings also follow the above description.

[0087] In order to improve product reliability and reduce transportation cost and maintenance cost, a large-size display device can be assembled by splicing a plurality of small-size display devices.

[0088] In order to avoid the split feeling of the display screen caused by splicing, it is necessary to reduce the frame size of a single small-size display device and reduce the seam width. The small-size display device includes a display panel, and the wire on the side of the display surface of the display panel can be connected to the circuit board (for example, a flexible circuit board) arranged on the side of the non-display surface of the display panel through side wiring, so that when a plurality of small-size display devices are spliced to form a large-size display device, the spacing between adjacent small-size display devices can be smaller, thereby reducing the seam width of the large-size display device formed by splicing a plurality of small-size display devices and improving the display quality.

[0089] As shown in FIG. 1, in some embodiments, the display panel 10 includes a substrate 1, a plurality of front electrodes 2, a plurality of connecting leads 3, and a plurality of back electrodes 4. The substrate 1 includes a first surface la and a second surface lb arranged oppositely, and a plurality of first side surfaces lc connecting the first surface la and the second surface lb, at least one of the plurality of first side surfaces lc of the substrate 1 is a selected first side surface lcc. The plurality of back electrodes 4 are arranged side by side and spaced apart on one side of the second surface lb. Each selected first side surface lcc is provided with a plurality of connecting leads 3 arranged side by side; each connecting lead 3 extends from the first surface la, through the selected first side surface lcc, to the second surface lb, and is electrically connected to one back electrode 4; that is, each connecting lead 3 includes a first portion 31 on one side of the first surface la, a second portion 32 on one side of the selected first side surface lcc, and a third portion 33 on one side of the second surface lb; the third portion 33 of each connecting lead 3 is electrically connected to one back electrode 4.

[0090] Exemplarily, the material of the substrate 1 includes but is not limited to glass. Moreover, when the material of the substrate 1 is glass, the electrode connection area of the display panel 10 can adopt a COG (Chip on glass, glass chip) structure.

[0091] Exemplarily, as shown in FIG. 1 and FIG. 2, the side of the first surface la of the substrate 1 is the front of the display panel 10, and the side of the first surface la of the substrate 1 is provided with a display area AA and an electrode connection area BB. The display area AA is provided with a film layer structure such as a driving circuit layer and a light emitting device layer 5. The light emitting device layer 5 includes at least three colors of light emitting devices 51, for example, including a first light emitting device 511, a second light emitting device 512, and a third light emitting device 513, at this time, the first color, the second color, and the third color (for example, red, green, and blue) are three primary colors. Exemplarily, the light emitting device 51 is a Micro LED (Micro Light Emitting Diode) and a Mini LED (Mini Light Emitting Diode Display). It should be noted that FIG. 1 and FIG. 2 show one possible arrangement of the first light emitting device 511, the second light emitting device 512, and the third light emitting device 513, and in actual application, the first light emitting device 511, the second light emitting device 512, and the third light emitting device 513 can also be arranged in other ways; that is, in some embodiments of the present disclosure, the arrangement of the plurality of light emitting devices 51 is not limited.

[0092] Exemplarily, as shown in FIG. 1 and FIG. 2, the first surface la side of the substrate 1 is a front surface of the display panel 10, and a plurality of front surface electrodes 2 can be disposed on the first surface la; for example, the plurality of front surface electrodes 2 can be disposed in the electrode connection region BB and arranged in parallel and spaced apart along a second direction Y, which is a direction parallel to the junction line of the selected first side surface lcc and the first surface la. The plurality of front surface electrodes 2 are electrically connected to at least part of a drive circuit layer (not shown in the figure). The first part 31 of the plurality of connection leads 3 is located on the first surface la side of the substrate 1 and electrically connected to the plurality of front surface electrodes 2 one by one. The extension direction of the first part 31 of the plurality of connection leads 3 is, for example, a direction perpendicular to the selected first side surface lcc of the substrate 1.

[0093] Exemplarily, the material of the front surface electrode 2 can include one or more of titanium (Ti), aluminum (Al), molybdenum (Mo), gold (Au), and silver (Ag).

[0094] In some examples, as shown in FIG. 5 and FIG. 6, the selected first side surface lcc includes a first sub-surface lcc1, a second sub-surface lcc2, and a third sub-surface lcc3. The first sub-surface lcc1 is parallel to the first reference edge H1 and perpendicular to the first surface la; the first reference edge H1 is the intersection line of the selected first side surface lcc and the second surface lb. The second sub-surface lcc2 is located between the first sub-surface lcc1 and the first surface la and is a bevel. The third sub-surface lcc3 is located between the first sub-surface lcc1 and the second surface lb and is a bevel.

[0095] It should be understood that when the first sub-surface lcc1 is parallel to the first reference edge H1 and perpendicular to the first surface la, the first sub-surface lcc1 is the part of the selected first side surface lcc that is perpendicular to the first surface la. Moreover, when the second sub-surface lcc2 is located between the first sub-surface lcc1 and the first surface la, the second sub-surface lcc2 can be understood as a connecting surface between the first sub-surface lcc1 and the first surface la; when the third sub-surface lcc3 is located between the first sub-surface lcc1 and the second surface lb, the third sub-surface lcc3 can be understood as a connecting surface between the first sub-surface lcc1 and the second surface lb; that is, the first sub-surface lcc1 and the first surface la, and the first sub-surface lcc1 and the second surface lb, are connected by bevels.

[0096] Exemplarily, as shown in FIG. 7 and FIG. 8, the process of forming the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3 can be a grinding process. The edge of the initial substrate 1A is ground by a grinding rod N with a set shape. After grinding, the edge of the initial substrate 1A can form the second sub-surface 1cc2 and the third sub-surface 1cc3 to form the substrate 1. Wherein, the angle between the formed second sub-surface 1cc2 and the horizontal plane is consistent with the angle between the part of the grinding rod N grinding the second sub-surface 1cc2 and the horizontal plane; the angle between the formed third sub-surface 1cc3 and the horizontal plane is consistent with the angle between the part of the grinding rod N grinding the third sub-surface 1cc3 and the horizontal plane. That is, the inclination of the second sub-surface 1cc2 and the third sub-surface 1cc3 can be designed by designing the shape of the grinding rod N to meet the design requirements.

[0097] Exemplarily, the surface morphology of the selected first side surface 1cc ground by the grinding rod N in the view angle perpendicular to the first sub-surface 1cc1 is shown in FIG. 9; and the selected first side surface 1cc in FIG. 9 includes the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3.

[0098] Exemplarily, as shown in FIG. 3, the distance D13 between the front electrode 2 and the selected first side surface 1cc ranges from 0 to 300 μm, for example, the distance D13 between the front electrode 2 and the selected first side surface 1cc can be 0 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm or 300 μm, etc. It should be noted that, in the case where the selected first side surface 1cc includes the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3, the distance between the front electrode 2 and the selected first side surface 1cc refers to the distance between the front electrode 2 and the second sub-surface 1cc2; and the distance D13 between the front electrode 2 and the selected first side surface 1cc can be 0 μm, that is, the front electrode 2 can directly contact the boundary of the second sub-surface 1cc2.

[0099] In some examples, the substrate 1 is a glass substrate, and the joint part between the second sub-surface 1cc2 in the selected first side surface 1cc of the substrate 1 and the first surface 1a is shown in FIG. 4,

[0100] Exemplarily, as shown in FIG. 1, the second surface 1b side of the substrate 1 is the back surface of the display panel 10, and the third part 33 of the plurality of connection leads 3 is located on the second surface 1b side of the substrate 1, that is, the third part 33 of the connection lead 3 is the part of the connection lead 3 located on the back surface of the display panel 10. The plurality of back surface electrodes 4 are arranged on the second surface 1b side of the substrate 1 and are arranged in parallel and spaced apart along the second direction Y. In some examples, the plurality of back surface electrodes 4 can be electrodes arranged on one side of a flexible circuit board (not shown in the figure), in which case the other side of the flexible circuit board can be connected to external circuits by arranging binding electrodes or can be directly connected to external circuits; the third part 33 of the plurality of connection leads 3 is electrically connected to the plurality of back surface electrodes 4 in a one-to-one correspondence. In some examples, the surface of the back surface electrode 4 is rougher than the smooth surface of the glass substrate.

[0101] Exemplarily, the material of the connection lead 3 can include metal materials such as silver, copper, etc.

[0102] In some examples, as shown in FIG. 1, the display panel 10 further includes a protective layer 6A. The protective layer 6A covers the side surface of the connection lead 3 and is configured to provide a protective effect to the connection lead 3, so as to avoid the connection lead 3 from being in contact with air and / or water vapor to cause water and oxygen corrosion, thereby affecting the electrical conductivity of the connection lead 3. Exemplarily, the material of the protective layer 6A can also include one or more of reinforcing materials and packaging materials, etc.

[0103] In some examples, as shown in FIG. 1, the display panel 10 further includes a light blocking layer 6B (not shown in the figure). The light blocking layer 6B covers the side of the protective layer 6A away from the connection lead 3 and the side of the first surface 1a of the substrate 1. The light blocking layer 6B, on the one hand, can be configured to prevent external light from entering the display area AA to affect the display effect, and on the other hand, can prevent the light emitted by the light emitting device layer 5 from leaking at the joint seam of the spliced display device.

[0104] In some embodiments, as shown in FIG. 1 and FIG. 10, the display panel 10 further includes a circuit board 8 arranged on the second surface 1b of the substrate 1; the circuit board 8 includes oppositely arranged third and fourth surfaces 8a and 8b, and a plurality of second side surfaces 8c connecting the third and fourth surfaces 8a and 8b; the third surface 8a is closer to the substrate 1 than the fourth surface 8b; the plurality of second side surfaces 8c include at least one selected second side surface 8cc; each selected second side surface 8cc corresponds to one selected first side surface 1cc. In the case where the display panel 10 further includes the circuit board 8, the plurality of back surface electrodes 4 can be arranged in parallel and spaced apart on the fourth surface 8b.

[0105] It should be understood that by arranging the circuit board 8 on the second surface 1b of the substrate 1, the circuit board 8 can serve as a carrier for the plurality of back surface electrodes 4.

[0106] Here, the number of the selected second side surface 8cc corresponds to the number of the selected first side surface 1cc, and the selected second side surface 8cc is located close to the selected first side surface 1cc corresponding thereto. The selected second side surface 8cc corresponding to the selected first side surface 1cc can be arranged in the third direction Z, which is the thickness direction of the substrate 1.

[0107] In some examples, in the case where the display panel 10 includes the wiring board 8, the third portion 33 of the connection lead 3 includes a portion on the second surface 1b, a portion on the selected second side surface 8cc, and a portion on the fourth surface 8b side, and the connection lead 3 extends from the first surface 1a, through the selected first side surface 1cc, to the edge of the second surface 1b, and further extends from the second surface 1b, the second side surface 8cc, to the fourth surface 8b. In this case, the portions of the third portions 33 of the plurality of connection leads 3 on the fourth surface 8b side are electrically connected to the plurality of back electrodes 4 one by one.

[0108] For example, as shown in FIG. 10, the distance D11 between the wiring board 8 and the third sub-surface 1cc3 is in the range of 0-1500 μm, such as 0 μm, 300 μm, 600 μm, 900 μm, 1200 μm, or 1500 μm. It should be noted that the distance D11 between the wiring board 8 and the third sub-surface 1cc3 can be 0 μm, that is, the wiring board 8 can be in direct contact with the boundary of the third sub-surface 1cc3.

[0109] For example, as shown in FIG. 10, the distance D12 between the back electrode 4 and the selected second side surface 8cc is in the range of 0-250 μm, such as 0 μm, 50 μm, 100 μm, 150 μm, 200 μm, or 250 μm. It should be noted that the distance D12 between the back electrode 4 and the selected second side surface 8cc can be 0 μm, that is, the side surface of the back electrode 4 corresponding to the selected second side surface 8cc (for example, the selected third side surface 4cc described in detail below) can be flush with the selected second side surface 8cc.

[0110] In some examples, the distance D11 between the wiring board 8 and the third sub-surface 1cc3 and the distance D12 between the back electrode 4 and the third sub-surface 1cc3 can be determined according to the product design specifications of the display panel 10.

[0111] In some embodiments, as shown in FIG. 1 and FIG. 10, the back electrodes 4 include a sixth surface 4a and a seventh surface 4b oppositely arranged, and a plurality of third side surfaces 4c connecting the sixth surface 4a and the seventh surface 4b. The sixth surface 4a is closer to the circuit board 8 than the seventh surface 4b. The plurality of third side surfaces 4cc includes a selected third side surface 4cc; the selected third side surface 4cc corresponds to a selected second side surface 8cc.

[0112] Here, the selected third side surface 4cc corresponds to the selected second side surface 8cc means that the selected third side surface 4cc is closer to the selected second side surface 8cc corresponding thereto; and the corresponding selected third side surface 4cc and the selected second side surface 8cc can be arranged along the third direction Z or substantially along the third direction Z.

[0113] It should be understood that, in the case where the back electrodes 4 include the sixth surface 4a and the seventh surface 4b oppositely arranged, the third part 33 of the connecting lead 3 can be electrically connected to the back electrode 4 by forming the third part 33 of the connecting lead 3 on the seventh surface 4b so that the third part 33 of the connecting lead 3 can be electrically connected to the back electrode 4.

[0114] In some embodiments, the plurality of connecting leads 3 are prepared by a printing process. In this case, as shown in FIG. 11, the preparation method of the display panel 10 includes the following steps, for example:

[0115] S1: Forming a plurality of front electrodes 2 on the front surface of a substrate mother board. In this step, other structures in the driving circuit layer are also formed.

[0116] Exemplarily, the process of forming the plurality of front electrodes 2 can be a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, or a chemical aqueous plating process, etc.

[0117] S2: Cutting the substrate mother board to form a plurality of substrates 1, the first surface 1a of the substrate 1 is provided with the plurality of front electrodes 2.

[0118] S3: Transferring a plurality of light emitting devices 51 to the front surface of the substrate 1, and welding the light emitting device 5 on the pad in the driving circuit layer to complete the die bonding.

[0119] S4: Attaching the circuit board 8 to the second surface 1b of the substrate 1, the fourth surface 8b of the circuit board 8 is provided with a plurality of back electrodes 4. Exemplarily, the back electrode 4 and the front electrode 2 can be opposite in the thickness direction Z of the substrate 1.

[0120] S5: forming a plurality of connection leads 3 on the first surface la of the substrate 1, the selected first side surface lcc, the second surface lb, and the selected second side surface 8cc and the fourth surface 8b of the circuit board 8 by using a printing process. The printing process can be, for example, a screen printing process, a pad printing process, a transfer printing process, or a 3D printing process.

[0121] In some examples, S4 further includes: curing the material of the connection leads 3 to form the plurality of connection leads 3.

[0122] S6: forming an initial protective layer on the plurality of connection leads 3 away from the surface of the substrate 1.

[0123] S7: curing the initial protective layer to form the protective layer 6A.

[0124] In some examples, S3 can be placed after S7, i.e., after the formation of the protective layer 6A (or after the completion of the side surface circuit), and then the plurality of light emitting devices 51 are transferred to the front surface of the substrate 1 (i.e., the flip chip light emitting device 51).

[0125] In S5 of the method for manufacturing the display panel 10, the plurality of connection leads 3 are formed on the first surface la of the substrate 1, the selected first side surface lcc, the second surface lb, and the selected second side surface 8cc and the fourth surface 8b of the circuit board 8. The connection leads 3 need to be formed on surfaces of different materials and / or surfaces of different topographies, resulting in differences in the topography of the formed connection leads 3 and differences in the resistance values of the connection leads 3 at different locations. Here, the different materials include, for example, one or more of glass, resin, polyimide, and metal; and the different topographies include, for example, one or more of a roughened glass side surface, a smooth glass back surface, and a surface with a sudden change in the third direction Z (see FIG. 13).

[0126] In some examples, as shown in FIGS. 12-15, the sudden change in the third direction Z includes a first gap Gl and a second gap G2. The first gap Gl is located at the edge of the circuit board 8 close to the selected first side surface lcc (or at the selected second side surface 8cc), and its size depends on the thickness L4 of the circuit board 8; the second gap G2 is located at the edge of the back electrode 4 close to the selected second side surface 8cc (or at the selected third side surface 4cc), and its size depends on the thickness L5 of the back electrode 4.

[0127] In some examples, the thickness of the first gap G1 can be reduced by reducing the thickness L4 of the circuit board 8, for example, the circuit board 8 can include a bonding layer 81 and a carrier body 82 arranged in a stack, and the thickness L4 of the first gap G1 can be reduced by reducing the thickness of the bonding layer 81 and / or the carrier body 82.

[0128] In some examples, the thickness L4 of the circuit board 8 ranges from 50 μm to 120 μm, for example, 50 μm, 60 μm, 75 μm, 9 μm, 100 μm, 110 μm or 120 μm, etc.

[0129] In some examples, the thickness L5 of the back electrode 4 ranges from 5 μm to 25 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 22 μm or 25 μm, etc.

[0130] It should be understood that, as shown in FIG. 16, under the influence of the first gap G1 (see FIG. 13) and the second gap G2 (see FIG. 13), there is a Z-direction area to be reinforced V2 on the formation surface of the connecting lead 3, which is located on the side of the second surface 1b of the substrate 1.

[0131] In some examples, the correspondence between the area to be reinforced V2 and the first surface 1a, the selected first side surface 1cc and the second surface 1b is shown in FIG. 16. In FIG. 16, the V1 part is the part of the area where the back electrode 4 is located away from the second gap G2 (see FIG. 13); the V3 part is the part of the second surface 1b away from the first gap G1 (see FIG. 13); the V4 part is the selected first side surface 1cc; the V5 part is the area where the front electrode 2 is located; in this case, the area to be reinforced V2 can include the area around the first gap G1, the area around the second gap G2 and the area between the first gap G1 and the second gap G2.

[0132] Based on this, as shown in FIG. 1 and FIGS. 17-19, some embodiments of the present disclosure provide a display panel 10, which further includes a buffer pad layer 7. The buffer pad layer 7 is located on the side of the circuit board 8 close to the selected first side surface 1cc, and at least covers the junction K1 of the fourth surface 8b and the selected second side surface 8cc of the circuit board 8. The third part 33 of the connecting lead 3 further includes a part located on the buffer pad layer 7. The ratio between the maximum value w max and the minimum value w min of the line width of the third part 33 of the connecting lead 3 ranges from 1.0 to 1.5, and the line width of the third part 33 of the connecting lead 3 is the dimension of the third part 33 of the connecting lead 3 in the direction perpendicular to the extension direction X thereof.

[0133] Exemplarily, the material of the cushion layer 7 can include resin; of course, the material of the cushion layer 7 can also include other materials; embodiments of the present disclosure do not limit this.

[0134] In some examples, the cushion layer 7 is a continuous whole layer structure, and it can be understood that multiple connection leads 3 share one cushion layer.

[0135] Exemplarily, the ratio between the maximum value w max and the minimum value w min of the line width of the third part 33 of the connection lead 3 can be 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5.

[0136] It should be understood that, as shown in FIG. 1 and FIGS. 17-19, when the cushion layer 7 is located on the side of the circuit board 8 close to the selected first side surface 1cc, and at least covers the junction K1 of the fourth surface 8b and the selected second side surface 8cc of the circuit board 8, the cushion layer 7 can at least cover the first gap G1 (see FIG. 13). Moreover, when the ratio between the maximum value w max and the minimum value w min of the line width of the third part 33 of the connection lead 3 ranges from 1.0 to 1.5, the maximum value w max and the minimum value w min of the line width of the third part 33 of the connection lead 3 are closer.

[0137] Here, the line width of the third part 33 of the connection lead 3 is the dimension of the third part 33 of the connection lead 3 in the direction perpendicular to the extension direction X thereof; as one possible implementation, the intersection line of the selected first side surface 1cc and the second surface 1b is set as the first reference edge H1; the third part 33 of the connection lead 3 has a first cross section (not shown in the figure) parallel to the first reference edge H1 and perpendicular to the second surface 1b, and the line width of the third part 33 of the connection lead 3 is the maximum of the multiple dimensions of the first cross section parallel to the first reference edge H1. For a clearer illustration, as shown in FIG. 19, the line width of the third part 33 of the connection lead 3 is shown by using the top view of the third part 33 of the connection lead 3, and the top view direction is the direction in which the second surface 1b points to the first surface 1a.

[0138] It can be understood that, in the first aspect, when the buffer pad layer 7 covers the first gap G1 (see FIG. 13), the buffer pad layer 7 can cover at least the area around the first gap G1 in the above-mentioned to-be-reinforced area V2 (see FIG. 16), and a part of the material of the buffer pad layer 7 can fill the area on the side of the first gap G1 close to the first selected side surface 1cc. In other words, the buffer pad layer 7 can form a gentle slope at the first gap G1. In this way, when the third part 33 of the connection lead 3 is formed, the third part 33 of the connection lead 3 also includes a part located on the buffer pad layer 7. In this way, compared with the case where the buffer pad layer 7 is not arranged, the abrupt gap of the surface of the third part 33 of the connection lead 3 in the third direction Z can be reduced, the difference in topography of the surface of the third part 33 of the connection lead 3 can be reduced, the difference in topography of the third part 33 of the connection lead 3 can be reduced, and the disconnection of the connection lead 3 can be prevented. In the second aspect, when the maximum value w max of the line width of the third part 33 of the connection lead 3 is closer to the minimum value w min of the line width of the third part 33 of the connection lead 3, the uniformity of the line width of the third part 33 of the connection lead 3 can be improved, and the difference in topography of the third part 33 of the connection lead 3 can be reduced. When the difference in topography of the third part 33 of the connection lead 3 is small, the conduction line formed by the connection lead 3 can be more stable, the connection lead 3 can meet the line resistance requirement, the controllability of the line resistance of the connection lead 3 can be improved, and the product reliability of the display panel 10 can be improved.

[0139] In addition, in the case where the material of the buffer pad layer 7 includes resin, the resin has good adhesion, the circuit board 8 can be more closely attached to the substrate 1, the displacement of the circuit board 8 on the second surface 1b when the temperature of the display panel 10 changes can be prevented, and the disconnection of the connection lead 3 caused by the displacement of the circuit board 8 can be prevented.

[0140] In some embodiments, as shown in FIGS. 1, 17, 18, and 20-23, the buffer pad layer 7 includes a first boundary 7A and a second boundary 7B, and the projections of the first boundary 7A and the second boundary 7B on the second surface 1b are arranged in the first direction X. The first boundary 7A is farther away from the back electrode 4 than the second boundary 7B in the first direction X. The first direction X is the extension direction of the third part 33 of the connection lead 3.

[0141] Here, the surface in contact with the first boundary 7A is not limited. For example, as shown in FIGS. 1, 17, 18, 23, and 24, the first boundary 7A can be located on the second surface lb in contact with the second surface lb. For another example, as shown in FIG. 21, the first boundary 7A can be located on the selected first side surface lcc in contact with the selected first side surface lcc, and in this case, the buffer pad layer 7 also covers the junction of the second surface lb and the selected first side surface lcc. For another example, as shown in FIG. 22, the first boundary 7A can be located on the first surface la in contact with the first surface la, and in this case, the buffer pad layer 7 also covers the selected first side surface lcc.

[0142] Here, the surface in contact with the second boundary 7B is not limited. For example, as shown in FIG. 24, the second boundary 7B can be located on the fourth surface 8b in contact with the fourth surface 8b. For another example, as shown in FIGS. 1, 17, 18, and 21-23, the second boundary 7B can be located on the seventh surface 4b in contact with the seventh surface 4b, and in this case, the buffer pad layer 7 also covers the junction K2 of the seventh surface 4b and the selected third side surface 4cc, i.e., the buffer pad layer 7 also covers the second step difference G2 (see FIG. 13).

[0143] In some examples, as shown in FIGS. 1, 17, 18, and 23, the first boundary 7A is located on the second surface lb, and the second boundary 7B is located on the seventh surface 4b. In this case, the buffer pad layer 7 completely covers the portion of the circuit board 8 between the back electrode 4 and the selected second side surface 8cc, and overlaps the back electrode 4. In this case, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the selected first side surface lcc, the second surface lb, the buffer pad layer 7, and the seventh surface 4b of the back electrode 4.

[0144] In other examples, as shown in FIG. 24, the first boundary 7A is located on the second surface lb, and the second boundary 7B is located on the portion of the circuit board 8 between the back electrode 4 and the selected second side surface 8cc. In this case, the buffer pad layer 7 does not completely cover the portion of the circuit board 8 between the back electrode 4 and the selected second side surface 8cc, and does not overlap the back electrode 4. In this case, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode, the selected first side surface lcc, the second surface lb, the buffer pad layer 7, the fourth surface 8b, the selected third side surface 4cc of the back electrode 4, and the seventh surface 4b of the back electrode 4.

[0145] In some embodiments, as shown in FIG. 24, the intersection of the selected first side surface 1cc and the second surface 1b is a first reference edge H1. A cross section of the buffer pad layer 7 perpendicular to the first reference edge H1 is a second cross section. In the second cross section, the distance D14 between the surface 7a of the buffer pad layer 7 away from the second surface 1b and the second surface 1b of the substrate 1 gradually increases from the first boundary 7A to the third position T3, and gradually decreases from the third position T3 to the second boundary 7B. That is, in the second cross section, the surface 7a of the buffer pad layer 7 away from the second surface 1b can be in a parabolic shape, and the third position T3 is located at the highest point of the parabola.

[0146] Some embodiments of the present disclosure also provide a method for manufacturing the display panel 10. As shown in FIG. 25, the method for manufacturing the display panel 10 includes R1-R5.

[0147] R1: providing a substrate 1; the substrate 1 includes a first surface 1a and a second surface 1b arranged oppositely, and a plurality of first side surfaces 1c connecting the first surface 1a and the second surface 1b; the plurality of first side surfaces 1c includes at least one selected first side surface 1cc.

[0148] R2: forming a circuit board 8 on the second surface 1b; the circuit board 8 includes a third surface 8a and a fourth surface 8b arranged oppositely, and a plurality of second side surfaces 8c connecting the third surface 8a and the fourth surface 8b; the third surface 8a is closer to the substrate 1 than the fourth surface 8b; the plurality of second side surfaces 8c includes at least one selected second side surface 8cc; each selected second side surface 8cc corresponds to one selected first side surface 1cc.

[0149] R3: forming a plurality of back electrodes 4 on the fourth surface 8b; the plurality of back electrodes 4 are arranged side by side and spaced apart on the fourth surface 8b.

[0150] R4: forming a buffer pad layer 7 on one side of the circuit board 8 close to the selected first side surface 1cc; the buffer pad layer 7 at least covers the junction K1 between the fourth surface 8b of the circuit board 8 and the selected second side surface 8cc.

[0151] R5: forming a plurality of connection leads 3; the plurality of connection leads 3 are arranged side by side and spaced apart; each connection lead 3 includes a first part 31 located on one side of the first surface 1a, a second part 32 located on one side of the selected first side surface 1cc, and a third part 33 located on one side of the second surface 1b; the third part 33 of each connection lead 3 is electrically connected to one back electrode 4; the third part 33 of the connection lead 3 includes a portion located on the buffer pad layer 7. The maximum value w max of the line width of the third part 33 of the connection lead 3 (see FIG. 19) is greater than the minimum value w minThe ratio between the width of the third portion 33 of the connection lead 3 and the width of the second portion 32 of the connection lead 3 is in the range of 1 to 1.5. The width of the third portion 33 of the connection lead 3 is the dimension of the third portion 33 of the connection lead 3 in the direction perpendicular to the extending direction X of the third portion 33 of the connection lead 3.

[0152] The preparation method of the display panel 10 has the same advantages as the display panel 10 described in the above embodiments, which will not be repeated here.

[0153] In some embodiments, the preparation method further comprises R6 after R5, as shown in FIG. 25.

[0154] R6: forming an initial protective layer on the surface of the plurality of connection leads 3 away from the substrate 1, and curing the initial protective layer to form the protective layer 6A.

[0155] It should be understood that, in the case where the display panel 10 further comprises the cushion layer 7, the process parameters can be adjusted adaptively when forming the third portion 33 of the connection lead 3. Here, the types of process parameters, and the adjustment methods of the process parameters are not limited. The adjustment method of the process parameters will be described exemplarily below by taking the 3D printing process as an example.

[0156] In some embodiments, the process of forming the plurality of connection leads 3 in FIGS. 1 and 13 is a 3D printing process, in which the material of the connection lead 3 is printed on the target surface by a needle. The process parameters of the 3D printing process include printing air pressure, printing speed, and needle-to-surface distance. The needle-to-surface distance refers to the distance between the needle and the target surface. Therefore, when the plurality of connection leads 3 are formed by the 3D printing process, the process parameters can be adjusted at the first gap G1 and / or the second gap G2 to widen and thicken the formed connection lead 3, so as to prevent the connection lead 3 from being disconnected at the first gap G1 and / or the second gap G2. Here, the adjustment method of the process parameters is, for example, one or more of increasing the printing air pressure, reducing the printing speed, and adjusting the needle-to-surface distance. The control mechanism of the above three process parameters on the width of the connection lead 3 will be described exemplarily below.

[0157] (1) Control mechanism of the needle diameter and the printing air pressure on the width of the connection lead 3

[0158] It should be understood that the viscosity of different printing materials is different, and the viscosity of the same material also changes with the printing process. Therefore, in order to ensure a uniform flow printing, the adjustment method of the needle diameter and / or the printing air pressure can be selected to keep the flow consistent during the printing process, so as to keep the width of the connection lead 3 consistent. For example, after selecting the needle diameter, the printing air pressure can be adjusted and compensated in real time by using a dispensing machine.

[0159] Exemplarily, the printing air pressure ranges from 10 psi to 80 psi, such as 10 psi, 20 psi, 30 psi, 40 psi, 50 psi, 60 psi, 70 psi or 80 psi, etc.

[0160] In some examples, to achieve a stable flow rate of 500 μl / s, the following two ways can be used: the first way is to select a needle diameter of 100 μm and set the initial printing air pressure to 10 psi; the second way is to select a needle diameter of 80 μm and set the initial printing air pressure to 13 psi.

[0161] In other examples, when the needle diameter is selected to be 100 μm, if the initial printing air pressure is set to 10 psi, a stable flow rate of 500 μl / s can be achieved; if the initial printing air pressure is set to 13 psi, a stable flow rate of 691 μl / s can be achieved.

[0162] It can be seen that by adjusting the needle diameter and / or the printing air pressure, the printing flow rate can reach the set flow rate. Therefore, by adjusting the needle diameter and / or the printing air pressure, the same stable flow rate of different materials can be achieved, or different stable flow rates of the same material can be achieved. Here, the specific adjustment method can be determined according to the actual printing situation, which is not limited here.

[0163] (2) Control mechanism of printing speed on the line width of the connecting lead 3

[0164] When the flow rate is kept constant, the printing speed can control the line width and thickness of the connecting lead 3. For example, the flow rate is set to L0 and kept constant during printing, the printing speed v is set, the line width of the connecting lead 3 formed is w, and the line thickness is h, then the flow rate L0, the printing speed v, and the line width w and the line thickness h of the connecting lead 3 satisfy the relationship: L0=n×v×w×h; wherein n is the printing flow rate coefficient, which is related to the properties of the printing material itself. In practical applications, the printing flow rate coefficient n can be obtained by simulation according to the material performance and flow rate value.

[0165] (3) Control mechanism of needle surface distance on the line width of the connecting lead 3

[0166] The line width of the formed connecting lead 3 is associated with the needle-face distance under other certain printing parameters. For example, on the one hand, when the needle-face distance is less than a threshold needle-face distance, the distance between the needle and the target surface is small, so that the target surface has a certain extrusion effect on the material of the connecting lead 3 in the needle, which affects the paste effect; moreover, the greater the needle-face distance, the weaker the extrusion effect; therefore, when the needle-face distance is less than the threshold needle-face distance, the greater the needle-face distance, the better the paste effect, and the greater the line width of the connecting lead 3; on the other hand, when the needle-face distance is greater than the threshold needle-face distance, the needle has a certain flattening effect on the material of the connecting lead 3, which can increase the line width of the formed connecting lead 3, and moreover, the greater the needle-face distance, the weaker the flattening effect; therefore, when the needle-face distance is greater than the threshold needle-face distance, the greater the needle-face distance, the smaller the line width of the formed connecting lead 3.

[0167] It should be understood that the relationship between the flow L0, the printing speed v, and the line width w and the line thickness h of the connecting lead 3 can be transformed as L0 / v = n x w x h, wherein the printing flow coefficient n is associated with the properties of the material itself. In some examples, the printing flow coefficient n is a constant value under the condition of a selected material and a material viscosity SPEC range; therefore, the printing flow coefficient n can be used as one of the parameters for evaluating the printing difficulty of the material of the connecting lead 3 during the selection and development of the material of the connecting lead 3. Moreover, under the conditions of the flow L0, the printing speed v, and the printing flow coefficient n, the line width w and the line thickness h of the connecting lead 3 can be stably controlled. Wherein w x h can be understood as the cross-sectional area of the connecting lead 3, and moreover, the needle-face distance can affect the line thickness h of the connecting lead 3, so that under the conditions of the flow L0, the printing speed v, and the printing flow coefficient n, the line width w of the connecting lead 3 can be adjusted by adjusting the needle-face distance.

[0168] In some examples, the influence of the needle-face distance on the line width w and the cross-sectional area of the connecting lead 3 is experimentally verified. The selected needle-face distances are M1-M7, the material of the connecting lead 3 is printed on the plane, and according to the printing order, the printed connecting lead 3 is divided into initial, middle and final sections, and the line width and cross-sectional area of the initial, middle and final sections of the connecting lead 3 are measured respectively. Wherein, FIG. 26 is the division of the initial, middle and final sections of the connecting lead 3 when the needle-face distance is M1-M7, it should be noted that in FIG. 26, the vertical red line is the area division line, and the 6 area division lines divide the connecting lead 3 into 7 areas, each area corresponds to a selected needle-face distance; FIG. 27 is the morphology of the printed connecting lead 3; FIG. 28 is the change curve of the line width of the initial, middle and final sections of the connecting lead 3 with the change of the needle-face distance; in addition, FIG. 28 also contains the column chart of the cross-sectional area of the connecting lead 3 with the change of the needle-face distance when the needle-face distance is M3-M7, and the change curve of the cross-sectional area of the connecting lead 3 with the change of the needle-face distance as a reference line.

[0169] As shown in FIG. 28, in a first aspect, the line width w of the connecting lead 3 increases with the increase of the needle-substrate distance, and finally tends to be stable, and the line width w of the connecting lead 3 tends to be stable is related to the diameter of the needle. In a second aspect, the cross-sectional area of the connecting lead 3 increases with the increase of the needle-substrate distance.

[0170] It can be seen that the needle-substrate distance can affect the line width w of the connecting lead 3, and therefore, in the case of determining the printing flow coefficient n, the line width w of the connecting lead 3 can be adjusted by changing the needle-substrate distance.

[0171] In some examples, the influence of the needle-substrate distance on the profile of the connecting lead 3 is experimentally verified. The experiment is divided into two groups. The printing conditions of the two groups of experiments are: a line route board 8 with a height of H0 is provided on the glass substrate to form a first step difference G1 (see FIG. 13). Before the first step difference G1, that is, when printing on the back of the glass substrate, the printing speed is set to v1, and the distance between the needle and the glass substrate 1 is H (i.e., the needle-substrate distance is H); when the needle moves to the first step difference G1 (i.e., when the connecting lead 3 climbs), the printing speed is reduced from v1 to v2, and the distance between the needle and the glass substrate 1 is increased from H to H+H0; after the connecting lead 3 climbs the first step difference G1, the distance between the needle and the glass substrate 1 is kept as H+H0 (at this time, the distance between the needle and the surface of the line route board 8 is H, i.e., the needle-substrate distance is H), and the printing is continued. In the two groups of experiments, the height H0 of the line route board 8 (i.e., the height of the first step difference G1) and the ratio of v2 / v1 are not the same. Specifically, in the first group of experiments, the height H0 of the line route board 8 is 40 μm, and the ratio of v2 / v1 is 0.6; in the second group of experiments, the height H0 of the line route board 8 is 20 μm, and the ratio of v2 / v1 is 0.83.

[0172] In the case of selecting the material of the connecting lead 3, the printing flow coefficient n is unchanged, and under this premise, according to the relationship L0=n×v×w×h, the printing flow L0 can be increased at the first step difference G1, and / or the printing speed v can be reduced, so that the cross-sectional area w×h of the connecting lead 3 is increased. Therefore, in the above two groups of experiments, the printing flow L0 is increased at the first step difference G1, and the printing speed v is reduced to ensure that the connecting lead 3 is continuous at the first step difference G1. Here, the dispensing machine can be used to adjust in real time, so that the printing speed is reduced from v1 to v2.

[0173] The morphology of the connecting lead 3 obtained in the first group of experiments is shown in FIG. 29, and the morphology of the connecting lead 3 obtained in the second group of experiments is shown in FIG. 30. It can be seen that by adjusting the printing flow L0 and the printing speed v at the first gap G1, the connecting lead 3 can be prevented from being disconnected at the first gap G1, and the morphology difference of the connecting lead 3 at the first gap G1 can be reduced to some extent. When the height of the first gap G1 is lower, the morphology difference of the connecting lead 3 at the first gap G1 is smaller.

[0174] Based on the above control mechanism, in some embodiments, as shown in FIG. 1, the process of forming the plurality of connecting leads 3 is a 3D printing process; and the first boundary 7A is located on the second surface 1b; in this case, the method of forming the third part 33 of the connecting lead 3 can include R5.1-R5.4.

[0175] R5.1: As shown in FIGS. 1 and 19, starting from the seventh position T7, the printing speed is set to the first printing speed, the needle pitch is set to the first needle pitch, and the third part 33 of the connecting lead 3 is printed. The seventh position T7 is located on the second surface 1b.

[0176] It can be understood that by setting in this way, the third part 33 of the connecting lead 3 can be printed separately, and thus, compared with the case where the second part 32 and the third part 33 of the connecting lead 3 are completed by the same process, the phenomenon of disconnection or poor connection of the connecting lead 3 at the junction of the second surface 1b and the selected first side surface 1cc can be avoided.

[0177] R5.2: As shown in FIGS. 1 and 19, when printing to the first position T1, the printing speed is lowered to the second printing speed, and the needle pitch is kept as the first needle pitch, and the third part 33 of the connecting lead 3 is continuously printed. The first position T1 is located on the second surface 1b, and is located on the side of the first boundary 7A away from the second boundary 7B.

[0178] It can be understood that the part of the surface 7a of the buffer pad layer 7 away from the second surface 1b and close to the first boundary 7A is ramp-shaped, and has a certain topographic difference with the second surface 1b; therefore, when the third part 33 of the connecting lead 3 is formed around the first boundary 7A, the state of the material of the connecting lead 3 changes from a planar printing state to an upward ramp printing state. Moreover, the material of the connecting lead 3 has a certain fluidity, and in this case, when the third part 33 of the connecting lead 3 is formed around the first boundary 7A, the line width of the third part 33 of the connecting lead 3 may decrease from the first boundary 7A. Therefore, by reducing the printing speed at the first position T1, the line width of the third part 33 of the connecting lead 3 gradually increases from the first position T1, so as to increase the line width of the third part 33 of the connecting lead 3, and thus the influence of the above topographic change on the line width of the third part 33 of the connecting lead 3 can be reduced, and the topographic difference of the third part 33 of the connecting lead 3 can be reduced.

[0179] R5.3: As shown in FIGS. 1 and 19, when printing to the second position T2, the printing speed is maintained as the second printing speed, and the needle pitch is increased to the second needle pitch, and the third part 33 of the connecting lead 3 is continuously printed. The second position T2 is located between the first boundary 7A and the third position T3 (see FIG. 24).

[0180] In some examples, after the connecting lead 3 is printed by the above method, the cross-sectional view of the display panel 10 obtained is as shown in FIG. 31.

[0181] It should be noted that, as shown in FIG. 24, since the cross section (for example, the second cross section) profile of the surface 7a of the buffer pad layer 7 away from the second surface 1b is a curve close to downward bending (for example, a downward parabolic shape), after the needle pitch is increased to the second needle pitch at the second position T2, the height of the needle (that is, the distance between the needle and the second surface 1b) changes from the second position T2 to the third position T3, and from the third position T3 to the fourth position T4, and the change value is changed with the topography of the buffer pad layer 7. Specifically, from the second position T2 to the third position T3, the needle pitch gradually decreases; from the third position T3 to the fourth position T4, the needle pitch gradually increases.

[0182] It can be understood that when the third part 33 of the connection lead 3 is formed on the surface 7a of the buffer pad layer 7 away from the second surface 1b, if the height of the needle (i.e. the distance between the needle and the second surface 1b) remains unchanged, the needle can collide with the buffer pad layer 7 (which can be referred to as needle collision) at the third position T3 or close to the third position T3, which can damage the needle. Therefore, by increasing the needle face distance to the second needle face distance at the second position T2, the needle is moved away from the buffer pad layer 7; for example, the distance between the needle and the second surface 1b can be greater than the distance between the third position T3 and the second surface 1b, so that the needle can be prevented from colliding with the buffer pad layer 7.

[0183] R5.4: As shown in FIG. 1 and FIG. 19, when printing to the fourth position T4, the printing speed is increased to the third printing speed, the needle face distance is decreased to the first needle face distance, and the third part 33 of the connection lead 3 is continuously printed. The fourth position T4 is located between the third position T3 and the second boundary 7B.

[0184] It can be understood that when the third part 33 of the connection lead 3 is formed around the third position T3, the state of the material of the connection lead 3 changes from the upward climbing printing state to the downward printing state; the material of the connection lead 3 has a certain fluidity, and in this case, when the third part 33 of the connection lead 3 is formed on the side of the third position T3 away from the first boundary 7A, the line width of the third part 33 of the connection lead 3 can decrease from the third position T3. Moreover, when printing to the side of the third position T3 away from the first boundary 7A, the risk of needle collision can be eliminated. Therefore, by adjusting the height of the needle (i.e. the distance between the needle and the second surface 1b) at the fourth position T4, the needle is moved towards the buffer pad layer 7, and the needle face distance is decreased; in this way, the wiping effect of the needle on the material of the connection lead 3 can be enhanced, and the line width of the formed connection lead 3 can be increased.

[0185] It should be noted that, as shown in FIG. 1, FIG. 19 and FIG. 20, in order to more clearly illustrate the first position T1, the second position T2, the fourth position T4, the seventh position T7, FIG. 19 also shows the following positions, specifically including: the eighth position T8 and the ninth position T9 are positions corresponding to when the line width of the third part 33 of the connection lead 3 is the set line width; the tenth position T10 is the boundary of the selected first side surface 1cc of the carrier body 82; the eleventh position T11 is the boundary of the selected first side surface 1cc of the adhesive layer 81; the twelfth position T12 is the outer contour of the substrate 1; and the thirteenth position T13 is the junction between the third sub-surface 1cc3 (see FIG. 6) and the second surface 1b.

[0186] The above is an exemplary description of the preparation method of the display panel 10, and the following will be exemplarily described some topographic features of the third part 33 of the connecting lead 3. It should be understood that the topographic features of the third part 33 of the connecting lead 3 described below can be caused by the above-mentioned adjustment of the process parameters in the 3D printing process, or can be caused by other ways of adjusting the process parameters in the 3D printing process, or can be caused by other process parameters adjustment of other processes other than the 3D printing process; that is, the causes of the topographic features of the third part 33 of the connecting lead 3 described below are not limited here.

[0187] In the following embodiments, the line width of the third part 33 of the connecting lead 3 reaches an extreme minimum line width or an extreme maximum line width at a certain position, which can be understood as that, near the position, there are a first adjacent area and a second adjacent area distributed on both sides thereof. When the extreme minimum line width is reached at the position, the line width of the third part 33 of the connecting lead 3 gradually decreases in the direction close to the position in the first adjacent area and the second adjacent area. When the extreme maximum line width is reached at the position, the line width of the third part 33 of the connecting lead 3 gradually increases in the direction close to the position in the first adjacent area and the second adjacent area.

[0188] In some embodiments, as shown in FIG. 19, the third part 33 of the connecting lead 3 includes a first position T1, which is located on the side of the first boundary 7A away from the second boundary 7B, and the distance D1 (hereinafter referred to as the first distance D1) between the first position T1 and the first boundary 7A in the first direction X is in the range of 50 μm-200 μm; the line width of the third part 33 of the connecting lead 3 gradually increases from the first position T1 to the first boundary 7A.

[0189] It should be understood that when the first position T1 is located on the side of the first boundary 7A away from the second boundary 7B, the connecting lead 3 at the first position T1 does not belong to the part of the connecting lead 3 located on the buffer pad layer 7; that is, the connecting lead 3 at the first position T1 does not contact the buffer pad layer 7. Moreover, when the first distance D1 is in the range of 50 μm-200 μm, a distance is left between the first position T1 and the first boundary 7A.

[0190] Exemplarily, the first distance D1 can be 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, 160 μm, 185 μm or 200 μm, etc.

[0191] In some examples, the third portion 33 of the connecting lead 3 has a set line width w0, and the line width of the third portion 33 of the connecting lead 3 at the first position T1 is greater than or equal to the set line width w0 of the third portion 33 of the connecting lead 3. Here, the difference between the line width of the third portion 33 of the connecting lead 3 at the first position T1 and the set line width w0 of the third portion 33 of the connecting lead 3 is not limited as long as the line width of the connecting lead 3 meets the electrical requirement and the overall fluctuation range of the line width of the connecting lead 3 meets the process requirement.

[0192] It can be understood that, as described above, the line width of the third portion 33 of the connecting lead 3 gradually increases from the first position T1 by adjusting the process parameters (e.g., reducing the printing speed) at the first position T1, which can increase the line width of the third portion 33 of the connecting lead 3. In this case, when the first distance D1 is small, the compensation effect can be affected, that is, the problem of affecting the printing effect due to the delay of adjusting the process parameters can occur; when the first distance D1 is large, the part with a larger line width in the third portion 33 of the connecting lead 3 is relatively more, and the material used to form the third portion 33 of the connecting lead 3 is relatively more. Therefore, by setting the first distance D1 in the range of 50 μm to 200 μm, the reliability of the above process parameter adjustment can be increased, and the preparation cost of the display panel 10 can be reduced.

[0193] In some embodiments, as shown in FIGS. 19 and 23, the line width of the third portion 33 of the connecting lead 3 reaches a first maximum line width w1 at a second position T2. The second position T2 is located between the first boundary 7A and the second boundary 7B. The distance D2 (hereinafter referred to as the second distance D2) between the second position T2 and the first boundary 7A in the first direction X is in the range of 0 to 600 μm.

[0194] Exemplarily, the second distance D2 can be 0 μm, 50 μm, 150 μm, 250 μm, 350 μm, 450 μm, 560 μm, or 600 μm, etc. It should be noted that the second distance D2 can be 0 μm, that is, the height of the needle can be adjusted at the first boundary 7A.

[0195] In this case, the line width of the third part 33 of the connecting lead 3 reaches the first maximum line width w1 at the second position T2. As a possible reason, the needle has a certain smearing effect on the material of the connecting lead 3, which can cause the line width of the connecting lead 3 formed to increase; the greater the needle surface distance, the weaker the smearing effect; when the needle moves away from the buffer pad layer 7 at the second position T2, the needle surface distance (i.e. the distance between the needle and the buffer pad layer 7) also increases, which weakens the smearing effect, and in this case, the line width of the third part 33 of the connecting lead 3 gradually decreases from the second position T2. Therefore, under the combined action of the topography of the buffer pad layer 7, the adjustment of the process parameters at the first position T1, and the change of the needle surface distance at the second position T2, the line width of the third part 33 of the connecting lead 3 can reach the first maximum line width w1 at the second position T2.

[0196] As can be understood, by adjusting the height of the needle at the second position T2, the needle can be prevented from colliding with the buffer pad layer 7, as described above.

[0197] In some embodiments, as shown in FIGS. 19 and 23, the ratio between the first maximum line width w1 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5.

[0198] Exemplarily, the ratio between the first maximum line width w1 and the line width of the third part 33 of the connecting lead 3 at the first position T1 can be 1.0, 1.1, 1.15, 1.3, 1.4 or 1.5.

[0199] In some examples, the first maximum line width w1 is the maximum value w max .

[0200] As can be understood, when the ratio between the first maximum line width w1 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5, the first maximum line width w1 is relatively close to the line width of the third part 33 of the connecting lead 3 at the first position T1, which can improve the uniformity of the line width of the third part 33 of the connecting lead 3, reduce the topography difference of the third part 33 of the connecting lead 3, make the conductive line formed by the connecting lead 3 more stable, and make the connecting lead 3 meet the line resistance requirement.

[0201] In some embodiments, as shown in FIG. 19 and FIG. 23, the third position T3 (see FIG. 24) is located between the second position T2 and the second boundary 7B. The line width of the third portion 33 of the connecting lead 3 reaches the minimum line width w2 at a fourth position T4, the fourth position T4 is located between the third position T3 and the second boundary 7B, and the distance D3 (hereinafter referred to as the third distance D3) between the fourth position T4 and the second boundary 7B in the first direction X is in the range of 0-400 μm.

[0202] Here, the description of the third position T3 can refer to the description of the third position T3 described above, which will not be repeated here. Moreover, as described above, when forming the third portion 33 of the connecting lead 3, the height of the needle can be adjusted at the second position T2 to prevent the needle from being struck. That is, the height of the needle needs to be adjusted before the third position T3, so in the case of forming the connecting lead 3 in the direction from the first boundary 7A to the second boundary 7B, the third position T3 is located between the second position T2 and the second boundary 7B.

[0203] It can be understood that, as described above, by adjusting the height of the needle (i.e. the distance between the needle and the second surface 1b) at the fourth position T4, the needle is moved towards the buffer pad layer 7, and the needle pitch is reduced; in this way, the smearing effect of the needle on the material of the connecting lead 3 can be enhanced, and the line width of the connecting lead 3 formed can be increased; in this case, the line width of the third portion 33 of the connecting lead 3 gradually increases from the fourth position T4. Therefore, under the combined action of the topography of the buffer pad layer 7 and the change of the needle pitch at the fourth position T4, the line width of the third portion 33 of the connecting lead 3 can reach the minimum line width w2 at the fourth position T4.

[0204] Exemplarily, the third distance D3 can be 0 μm, 50 μm, 160 μm, 250 μm, 340 μm or 400 μm, etc. It should be noted that the third distance D3 can be 0 μm, that is, the height of the needle can be adjusted at the second boundary 7B.

[0205] In some embodiments, as shown in FIG. 19 and FIG. 23, the ratio between the minimum line width w2 and the line width of the third portion 33 of the connecting lead 3 at the first position T1 is in the range of 1.0-1.5.

[0206] Exemplarily, the ratio between the minimum line width w2 and the line width of the third portion 33 of the connecting lead 3 at the first position T1 can be 1.0, 1.1, 1.2, 1.25, 1.3, 1.4 or 1.5, etc. That is, the minimum line width w2 is greater than or equal to the line width of the third portion 33 of the connecting lead 3 at the first position T1.

[0207] It can be understood that, when the ratio between the minimum line width w2 and the line width of the third part 33 of the connecting lead 3 at the first position T1 is in the range of 1.0-1.5, the minimum line width w2 is closer to the line width of the third part 33 of the connecting lead 3 at the first position T1, and in the case that the line width of the third part 33 of the connecting lead 3 at the first position T1 is close to or the same as the set line width w0 of the third part 33 of the connecting lead 3, the minimum line width w2 can be close to the set line width w0, so that the uniformity of the line width of the third part 33 of the connecting lead 3 can be improved, the topography difference of the third part 33 of the connecting lead 3 can be reduced, the conducting line formed by the connecting lead 3 can be more stable, and the connecting lead 3 can meet the line resistance requirement.

[0208] In some embodiments, as shown in FIGS. 19 and 33, the line width of the third part 33 of the connecting lead 3 reaches a second maximum line width w3 at a fifth position T5. The fifth position T5 is located on the side of the second boundary 7B away from the first boundary 7A. The distance (hereinafter referred to as a fourth distance D4) between the fifth position T5 and the second boundary 7B in the first direction X is in the range of 0-150 μm.

[0209] It should be understood that, when the fifth position T5 is located on the side of the second boundary 7B away from the first boundary 7A, the connecting lead 3 at the fifth position T5 does not belong to the part of the connecting lead 3 located on the buffer pad layer 7; that is, the connecting lead 3 at the fifth position T5 does not contact the buffer pad layer 7.

[0210] Exemplarily, the fourth distance D4 can be 0 μm, 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 125 μm, or 150 μm, etc. It should be noted that the fourth distance D4 can be 0 μm, that is, the second maximum line width w3 can be reached at the second boundary 7B.

[0211] It can be understood that, as described above, by adjusting the height of the needle at the fourth position T4, the needle is moved towards the second surface 1b, at this time, due to the decrease in the height of the needle, the material of the connecting lead 3 is accumulated at the needle, and the line width of the third part 33 of the connecting lead 3 is increased. Moreover, although the printing speed is increased to the third printing speed at the fourth position T4, the increase in the printing speed cannot completely consume the accumulation of the material of the connecting lead 3 caused by the height of the needle, so that the line width of the third part 33 of the connecting lead 3 gradually increases from the fourth position T4 to the fifth position T5, and reaches the second maximum line width w3.

[0212] In some embodiments, as shown in FIGS. 19 and 23, in the case that the line width of the third part 33 of the connecting lead 3 reaches a first maximum line width w1 at the second position T2, the second maximum line width w3 is less than or equal to the first maximum line width w1.

[0213] In some examples, the second maximum line width w3 is equal to the first maximum line width w1. At this time, in the case of ignoring the influence of the topography of the buffer pad layer 7, the influence of the adjustment of the process parameter (e.g., the printing speed reduction) at the first position T1 on the line width of the third part 33 of the connecting lead 3 is equivalent to the influence of the adjustment of the process parameter (e.g., the printing speed increase and the reduction of the needle pitch) at the fourth position T4 on the line width of the third part 33 of the connecting lead 3.

[0214] In some examples, the second maximum line width w3 is less than the first maximum line width w1. At this time, in the case of ignoring the influence of the topography of the buffer pad layer 7, the influence of the adjustment of the process parameter (e.g., the printing speed reduction) at the first position T1 on the line width of the third part 33 of the connecting lead 3 is greater than the influence of the adjustment of the process parameter (e.g., the printing speed increase and the reduction of the needle pitch) at the fourth position T4 on the line width of the third part 33 of the connecting lead 3.

[0215] In some embodiments, as shown in FIG. 1 and FIG. 19, the ratio between the second maximum line width w3 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5.

[0216] Exemplarily, the ratio between the second maximum line width w3 and the line width of the third part 33 of the connecting lead 3 at the first position T1 can be 1.0, 1.1, 1.2, 1.3, 1.35, 1.4, or 1.5, etc. That is, the second maximum line width w3 is greater than or equal to the line width of the third part 33 of the connecting lead 3 at the first position T1.

[0217] It can be understood that when the ratio between the second maximum line width w3 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5, the second maximum line width w3 is relatively close to the line width of the third part 33 of the connecting lead 3 at the first position T1, and in the case that the line width of the third part 33 of the connecting lead 3 at the first position T1 is close to or the same as the set line width w0 of the third part 33 of the connecting lead 3, the second maximum line width w3 can be relatively close to the set line width w0, so that the uniformity of the line width of the third part 33 of the connecting lead 3 can be improved, the topography difference of the third part 33 of the connecting lead 3 can be reduced, the conducting line formed by the connecting lead 3 can be more stable, and the connecting lead 3 can meet the line resistance requirement.

[0218] In some embodiments, as shown in FIG. 19 and FIG. 23, the third portion 33 of the connecting lead 3 further comprises a sixth position T6. The sixth position T6 is located on the side of the fifth position T5 away from the second boundary 7B. The sixth position T6 is located at a distance (hereinafter referred to as a fifth distance D5) in the first direction X from the second boundary 7B in a range of 50 μm ~ 200 μm. The line width of the third portion 33 of the connecting lead 3 gradually decreases from the fifth position T5 to the sixth position T6.

[0219] It should be understood that when the sixth position T6 is located on the side of the fifth position T5 away from the second boundary 7B, the connecting lead 3 at the sixth position T6 does not belong to the portion of the connecting lead 3 located on the buffer pad layer 7; that is, the connecting lead 3 at the sixth position T6 is not in contact with the buffer pad layer 7.

[0220] Exemplarily, the fifth distance D5 can be 50 μm, 70 μm, 90 μm, 110 μm, 130 μm, 150 μm, 180 μm, or 200 μm, etc.

[0221] It can be understood that, as described above, by adjusting the height of the needle at the fourth position T4 to move the needle towards the second surface 1b, at this time, due to the decrease in the height of the needle, the material of the connecting lead 3 at the needle is accumulated, and the line width of the third portion 33 of the connecting lead 3 increases. Moreover, although the printing speed is increased to the third printing speed at the fourth position T4, the increase in the printing speed cannot completely consume the accumulation of the material of the connecting lead 3 caused by the height of the needle. That is, the consumption of the accumulation of the material of the connecting lead 3 caused by the height of the needle requires a certain time, and in this case, the line width of the third portion 33 of the connecting lead 3 will show a trend of gradually increasing first and then gradually decreasing until the consumption of the accumulation of the material of the connecting lead 3 caused by the height of the needle is completed. The above-mentioned sixth position T6 can be understood as the position corresponding to the moment when the accumulation of the material is consumed.

[0222] In some embodiments, as shown in FIG. 19 and FIG. 23, the first boundary 7A is located on the second surface 1b. The line width of the third portion 33 of the connecting lead 3 reaches a third maximum line width w4 at a seventh position T7. The seventh position T7 is located on the second surface 1b and has a distance (hereinafter referred to as a sixth distance D6) in the first direction X from the selected first side surface 1cc in a range of 50 μm ~ 150 μm.

[0223] It should be noted that when the selected first side surface 1cc comprises the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3, the sixth distance D6 is the distance between the seventh position T7 and the third sub-surface 1cc3.

[0224] It should be understood that when the sixth distance D6 ranges from 50 pm to 150 pm, the seventh position T7 is arranged at a distance from the selected first side surface 1cc.

[0225] Exemplarily, the sixth distance D6 can be 50 pm, 70 pm, 90 pm, 110 pm, 120 pm, 140 pm, or 150 pm, etc.

[0226] It can be understood that, as described above, by arranging the third part 33 of the connecting lead 3 to include the seventh position T7, the third part 33 of the connecting lead 3 can be printed separately starting from the seventh position T7, and the third part 33 of the connecting lead 3 is connected to the second part 32 of the connecting lead 3 at the seventh position T7. In this way, the phenomenon of disconnection or poor connection of the connecting lead 3 at the junction of the second surface 1b and the selected first side surface 1cc can be avoided. Moreover, after the previous printing, a portion of the material of the connecting lead 3 is left on the needle, and in this case, the third part 33 of the connecting lead 3 is printed starting from the seventh position T7, and the residual material will flow out together with the new material, so that the line width of the third part 33 of the connecting lead 3 reaches the third maximum line width w4 at the seventh position T7.

[0227] Moreover, when the sixth distance D6 is small, the seventh position T7 can be close to the selected first side surface 1cc, which increases the difficulty of operation; when the sixth distance D6 is large, the second part 32 of the connecting lead 3 leaves more on the second surface 1b, which can increase the appearance difference of the third part 33 of the connecting lead 3. Therefore, by arranging the sixth distance D6 to range from 50 pm to 150 pm, the reliability of the 3D printing operation can be increased, and the appearance difference of the third part 33 of the connecting lead 3 can be reduced.

[0228] In some embodiments, as shown in FIGS. 19 and 23, when the line width of the third part 33 of the connecting lead 3 reaches the first maximum line width w1 at the second position T2, the third maximum line width w4 is less than or equal to the first maximum line width w1.

[0229] In some examples, the third maximum line width w4 is equal to the first maximum line width w1. At this time, ignoring the influence of the appearance of the buffer pad layer 7, the adjustment of the process parameters at the first position T1 (for example, reducing the printing speed) has an effect on the line width of the third part 33 of the connecting lead 3, which is equivalent to the influence of the residual material of the needle on the line width of the third part 33 of the connecting lead 3 at the seventh position T7.

[0230] In some examples, the third maximum line width w4 is less than the first maximum line width w1. At this time, the influence of the adjustment of the process parameter (for example, the printing speed is reduced) at the first position T1 on the line width of the third part 33 of the connecting lead 3 is greater than the influence of the needle residual material at the seventh position T7 on the line width of the third part 33 of the connecting lead 3, when the influence of the topography of the buffer pad layer 7 is ignored.

[0231] In some embodiments, as shown in FIGS. 19 and 23, the ratio between the third maximum line width w4 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5.

[0232] Exemplarily, the ratio between the third maximum line width w4 and the line width of the third part 33 of the connecting lead 3 at the first position T1 can be 1.0, 1.13, 1.2, 1.3, 1.36, 1.4, or 1.5, etc. That is, the third maximum line width w4 is greater than or equal to the line width of the third part 33 of the connecting lead 3 at the first position T1.

[0233] It can be understood that when the ratio between the third maximum line width w4 and the line width of the third part 33 of the connecting lead 3 at the first position T1 ranges from 1.0 to 1.5, the third maximum line width w4 is closer to the line width of the third part 33 of the connecting lead 3 at the first position T1, and when the line width of the third part 33 of the connecting lead 3 at the first position T1 is close to or the same as the set line width w0 of the third part 33 of the connecting lead 3, the third maximum line width w4 can be close to the set line width w0. In this way, the uniformity of the line width of the third part 33 of the connecting lead 3 can be improved, the topography difference of the third part 33 of the connecting lead 3 can be reduced, the formed conduction line of the connecting lead 3 can be more stable, and the connecting lead 3 can meet the line resistance requirement.

[0234] The above is an exemplary description of some topographic features of the third part 33 of the connecting lead 3. The topography, setting position, and other structural features of the buffer pad layer 7 will be described exemplarily below.

[0235] In some embodiments, as shown in FIG. 24, the first boundary 7A is located on the second surface 1b; and the intersection line of the selected first side surface 1cc and the second surface 1b is the first reference edge H1. The surface of the buffer pad layer 7 away from the second surface 1b of the substrate 1 is the fifth surface 7a. The cross section of the fifth surface 7a perpendicular to the first reference edge H1 is the first line segment H2. The first line segment H2 is a curved segment. The included angle a between the tangent of the first line segment H2 and the second surface 1b ranges from 0° to 40°.

[0236] It should be understood that, in the case where the first boundary 7A is located on the second surface 1b, the fifth surface 7a is located on the side of the second surface 1b away from the first surface 1a, and is located on the side of the selected first side surface 1cc close to the selected second side surface 8cc.

[0237] In some examples, as shown in FIG. 24, the first line segment H2 can be a curve that is curved downward, for example, can be a downward parabolic shape, as described previously. At this time, among the tangent lines of the first line segment H2, the tangent line with the largest included angle with the second surface 1b is the tangent line at the first boundary 7A or the second boundary 7B.

[0238] Exemplarily, the included angle a between the tangent line of the first line segment H2 and the second surface 1b can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, 36°, or 40°, etc.

[0239] It can be understood that, through the above setting, the included angle a between the tangent line of the first line segment H2 and the second surface 1b is small, so that the slope of the part of the buffer pad layer 7 located between the third position T3 and the first boundary 7A, and the slope of the part of the buffer pad layer 7 located between the third position T3 and the second boundary 7B, are both within a small range, so that when forming the part of the connecting lead 3 located on the buffer pad layer 7, the material of the connecting lead 3 can be in a form of climbing a gentle slope, which can improve the uniformity of the third part 33 of the connecting lead 3 formed, and reduce the difference in the topography of the third part 33 of the connecting lead 3.

[0240] In some embodiments, as shown in FIG. 21, the first boundary 7A is located on the selected first side surface 1cc. The size (hereinafter referred to as the first size L1) of the part of the selected first side surface 1cc covered by the buffer pad layer 7 in the direction Z perpendicular to the first reference edge H1 ranges from 0 to 30 pm.

[0241] In some examples, the direction Z perpendicular to the first reference edge H1 is the thickness direction of the substrate 1.

[0242] Exemplarily, the first size L1 can be 0 pm, 5 pm, 10 pm, 15 pm, 19 pm, 25 pm, or 30 pm, etc. It should be noted that the first size L1 can be 0 pm; at this time, the first boundary 7A is located at the joint of the selected first side surface 1cc and the second surface 1b, in other words, the first boundary 7A overlaps with the first reference edge H1.

[0243] In some examples, as shown in FIG. 21, the first boundary 7A is located on the third sub-surface 1cc3, at this time, the first dimension L1 can be determined according to the angle γ between the third sub-surface 1cc3 and the second surface 1b (see FIG. 5 and FIG. 6), the dimension of the third sub-surface 1cc3 perpendicular to the first reference edge H1, or the viscosity of the material of the buffer pad layer 7, etc.

[0244] It can be understood that when the first boundary 7A is located on the selected first side surface 1cc, the buffer pad layer 7 also covers the junction of the selected first side surface 1cc and the second surface 1b, so that the sharpness of the junction of the selected first side surface 1cc and the second surface 1b can be reduced, the stress on the connecting lead 3 at the junction of the selected first side surface 1cc and the second surface 1b can be reduced, and the possibility of the connecting lead 3 being broken or deformed under stress in subsequent processes (for example, the high-temperature curing process of the protective layer 6A of the connecting lead 3) can be reduced.

[0245] In some embodiments, as shown in FIG. 5-FIG. 8, the angle β between the second sub-surface 1cc2 and the first surface 1a ranges from 110° to 160°; and / or, the angle γ between the third sub-surface 1cc3 and the second surface 1b ranges from 110° to 160°.

[0246] It should be understood that, as shown in FIG. 5 and FIG. 6, when the substrate 1 is placed horizontally, when the angle β between the second sub-surface 1cc2 and the first surface 1a ranges from 110° to 160°, the angle between the second sub-surface 1cc2 and the horizontal plane ranges from 20° to 70°. When the angle γ between the third sub-surface 1cc3 and the second surface 1b ranges from 110° to 160°, the angle between the third sub-surface 1cc3 and the horizontal plane ranges from 20° to 70°.

[0247] Exemplarily, the angle β between the second sub-surface 1cc2 and the first surface 1a can be 110°, 120°, 130°, 135°, 140°, 145°, 150° or 160°, etc.

[0248] Exemplarily, the angle γ between the third sub-surface 1cc3 and the second surface 1b can be 110°, 120°, 125°, 130°, 135°, 140°, 150° or 160°, etc.

[0249] As described above, when the second sub-surface 1cc2 and the third sub-surface 1cc3 are formed by using the above-mentioned grinding process, the angle β between the second sub-surface 1cc2 and the first surface 1a, and the angle γ between the third sub-surface 1cc3 and the second surface 1b can be within the above-mentioned ranges by designing the shape of the grinding rod N.

[0250] In some examples, the substrate 1 is a glass substrate, the angle β between the second sub-surface 1cc2 and the first surface 1a is 135°, the angle γ between the third sub-surface 1cc3 and the second surface 1b is 135°, and the selected first side surface 1cc can be as shown in FIG. 9. As shown in FIG. 9, the selected first side surface 1cc can include a rough glass surface.

[0251] For example, in actual applications, the angle β between the second sub-surface 1cc2 and the first surface 1a and the angle γ between the third sub-surface 1cc3 and the second surface 1b can be determined according to the distance between the circuit board 8 and the first sub-surface 1cc and the process of connecting the connecting lead 3. For example, when the selected second side surface 8cc of the circuit board 8 is located on the side of the first reference edge H1 away from the second surface 1b, the angle γ between the third sub-surface 1cc3 and the second surface 1b can be greater than the angle β between the second sub-surface 1cc2 and the first surface 1a. For more details, please refer to the part of the material of the buffer layer 7 embedded in the area between the third sub-surface 1cc3 and the third surface 8a described in detail below, which will not be described here again. For another example, when the connecting lead 3 is formed by a 3D printing process, the angle β between the second sub-surface 1cc2 and the first surface 1a and the angle γ between the third sub-surface 1cc3 and the second surface 1b can be selected according to the printing material and the printing parameters, so that the material of the connecting lead 3 can be stably overlapped between the selected first side surface 1cc and the first surface 1a and between the selected first side surface 1cc and the second surface 1b.

[0252] It can be understood that when the angle β between the second sub-surface 1cc2 and the first surface 1a is smaller (for example, greater than or equal to 90° and less than 110°), the sharpness of the angle β between the second sub-surface 1cc2 and the first surface 1a is higher; when the angle β between the second sub-surface 1cc2 and the first surface 1a is larger (for example, greater than 160° and less than or equal to 180°), the sharpness of the angle between the second sub-surface 1cc2 and the first sub-surface 1cc1 is higher. Therefore, when the angle β between the second sub-surface 1cc2 and the first surface 1a is in the range of 110°-160°, the angle β between the second sub-surface 1cc2 and the first surface 1a can be in a suitable range, the sharpness of the angle β between the second sub-surface 1cc2 and the first surface 1a and the angle between the second sub-surface 1cc2 and the first sub-surface 1cc1 are both smaller, the stress on the connecting lead 3 at the junction between the second sub-surface 1cc2 and the first surface 1a and at the junction between the second sub-surface 1cc2 and the first sub-surface 1cc1 is smaller, and the possibility of the connecting lead 3 being broken or deformed under stress in subsequent processes (for example, the high-temperature curing process of the protective layer 6A of the connecting lead 3) can be reduced.

[0253] Here, as for the technical effect when the angle γ between the third sub-surface 1cc3 and the second surface 1b is in the range of 110°-160°, reference can be made to the technical effect when the angle β between the second sub-surface 1cc2 and the first surface 1a is in the range of 110°-160°, which will not be repeated here.

[0254] In some embodiments, as shown in FIG. 22, the display panel 10 further comprises a plurality of front electrodes 2. The plurality of front electrodes 2 are arranged side by side on the first surface 1a. Each front electrode 2 corresponds to one back electrode 4. Among them, the first boundary 7A is located at one side of the first surface 1a and in contact with the plurality of front electrodes 2.

[0255] It should be understood that when the first boundary 7A is located at one side of the first surface 1a and in contact with the plurality of front electrodes 2, the buffer pad 7 is a C-shaped pad; at this time, the buffer pad 7 not only covers the first gap G1 (see FIG. 13), but also covers the junction of the first surface 1a and the selected first side surface 1cc, and the junction of the selected first side surface 1cc and the second surface 1b, in other words, the buffer pad 7 also covers the selected first side surface 1cc.

[0256] It can be understood that when the buffer pad 7 is a C-shaped pad, the buffer pad 7 can cover the selected first side surface 1cc, so that, on the one hand, when the buffer pad 7 is a C-shaped pad, the length of the connecting lead 3 is shorter than when the circuit board 8 is spaced apart from the first sub-surface 1cc and the connecting lead 3 is also distributed on the second surface 1b, so that the connecting lead 3 can realize a shorter connection line between the front electrode 2 and the back electrode 4; on the other hand, it can make the material of the connecting lead 3 formed at the junction of the first surface 1a and the selected first side surface 1cc, and the junction of the selected first side surface 1cc and the second surface 1b, the surface sharpness attached is lower, which can reduce the possibility of the connecting lead 3 breaking or deforming under stress in subsequent processes (for example, the high-temperature curing process of the protective layer 6A of the connecting lead 3).

[0257] In some examples, the selected third side surface 4cc is farther away from the selected first side surface 1cc than the selected second side surface 8cc. That is, the normal projections of the selected third side surface 4cc, the selected second side surface 8cc, and the selected first side surface 1cc on the first surface 1a are arranged in order along the first direction X.

[0258] In this case, the first boundary 7A can be located at one side of the first surface 1a and in contact with the plurality of front electrodes 2; and the second boundary 7B can be located at the fourth surface 8b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be attached to the front electrode 2, the buffer pad 7, the fourth surface 8b, the selected third side surface 4cc, and the seventh surface 4b in order. Alternatively,

[0259] The first boundary 7A can be located on one side of the first surface la and in contact with the plurality of front electrodes 2; the second boundary 7B can be located on the seventh surface 4b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the buffer pad layer 7, and the seventh surface 4b.

[0260] In yet another example, the selected second side surface 8cc is flush with the selected third side surface 4cc; the selected first side surface 1cc is spaced apart from the selected second side surface 8cc.

[0261] In this case, the first boundary 7A can be located on one side of the first surface la and in contact with the plurality of front electrodes 2; the second boundary 7B can be located on the fourth surface 8b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the buffer pad layer 7, the fourth surface 8b, the selected third side surface 4cc, and the seventh surface 4b. Alternatively,

[0262] The first boundary 7A can be located on one side of the first surface la and in contact with the plurality of front electrodes 2; the second boundary 7B can be located on the seventh surface 4b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the buffer pad layer 7, and the seventh surface 4b.

[0263] In yet another example, the selected second side surface 8cc is flush with the selected third side surface 4cc; the selected first side surface 1cc is spaced apart from the selected second side surface 8cc.

[0264] In this case, the first boundary 7A can be located on one side of the first surface la and in contact with the plurality of front electrodes 2; the second boundary 7B can be located on the seventh surface 4b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the buffer pad layer 7, and the seventh surface 4b.

[0265] In yet another example, the corresponding selected second side surface 8cc and the selected third side surface 4cc are flush, and the selected second side surface 8cc and the selected third side surface 4cc are located on the side of the first reference edge H1 away from the second surface lb. At this time, compared with the above three cases, the shortest connecting line can be achieved; that is, the connecting lead 3 can be made shorter.

[0266] In this case, the first boundary 7A can be located on one side of the first surface la and in contact with the plurality of front electrodes 2; the second boundary 7B can be located on the seventh surface 4b; at this time, when the connecting lead 3 is formed, the material of the connecting lead 3 can be sequentially attached to the front electrode 2, the buffer pad layer 7, and the seventh surface 4b.

[0267] It should be noted that, in the case where the selected first side surface 1cc includes the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3, the selected first side surface 1cc being flush with the selected second side surface 8cc or the selected second side surface 4cc means that the first sub-surface 1cc1 is flush with the selected second side surface 8cc or the selected second side surface 4cc.

[0268] In some embodiments, as shown in FIG. 22, the corresponding selected second side surface 8cc and the selected third side surface 4cc are flush, the selected second side surface 8cc and the selected third side surface 4cc are located on the side of the first reference edge H1 away from the second surface 1b. The angle γ (see FIG. 6) between the third sub-surface 1cc3 and the second surface 1b is less than or equal to the angle β (see FIG. 6) between the second sub-surface 1cc2 and the first surface 1a. The material of the buffer pad layer 7 is embedded in the area between the third sub-surface 1cc3 and the third surface 8a.

[0269] In some examples, the normal projection of the selected second side surface 8cc and the selected third side surface 4cc on a reference plane can be located between the normal projection of the first reference edge H1 on the reference plane and the normal projection of the first sub-surface 1cc1 on the reference plane, the reference plane being a plane parallel to the second surface 1b.

[0270] It should be understood that, through the above arrangement, the buffer pad layer 7 is a C-shaped pad layer, and at this time, R2 and R3 in the preparation method of the display panel 10 can include: first, the circuit board 8 attached with the plurality of back electrodes 4 can be attached to the second surface 1b, so that the selected second side surface 8cc and the selected third side surface 4cc are located on the side of the first reference edge H1 away from the second surface 1b, and the selected second side surface 8cc and the selected third side surface 4cc are flush (which can be understood as flush attachment); or, the selected second side surface 8cc and the selected third side surface 4cc are located on the side of the first reference edge H1 away from the second surface 1b, and the selected second side surface 8cc and the selected third side surface 4cc exceed the selected first side surface 1cc (which can be understood as excess attachment); then, a cutting process (such as a laser cutting process) is used to remove the excess material of the circuit board 8 and / or the back electrode 4.

[0271] Exemplarily, in the case that the buffer pad layer 7 is a C-shaped pad layer, the preparation method of the display panel 10 can be as shown in FIG. 32. Wherein, the description about R1'~R3', R5' and R6' can refer to the description about R1~R3, R5 and R6; R4' can include: forming the C-shaped buffer pad layer 7. Exemplarily, the process of forming the C-shaped buffer pad layer 7 can be a printing process; and, in the printing process, as shown in FIG. 33, the needle head Q can be perpendicular to the surface to be printed (for example, the first sub-surface 1cc1 of the selected first side surface 1cc); or, as shown in FIG. 34, the needle head Q can also be arranged at an angle with the surface to be printed (for example, the first sub-surface 1cc1 of the selected first side surface 1cc). It should be understood that in this process, the material of the buffer pad layer 7 can be embedded in the area between the third sub-surface 1cc3 and the third surface 8a.

[0272] It can be understood that, through the above arrangement, on the one hand, the connecting lead 3 can be made shorter, and the material used to form the connecting lead 3 can be less, thereby reducing the preparation cost of the display panel 10; on the other hand, the process feasibility of attaching the circuit board 8 to the substrate 1 and / or forming the buffer pad layer 7 can be improved. Moreover, when the angle between the third sub-surface 1cc3 and the second surface 1b is less than or equal to the angle between the second sub-surface 1cc2 and the first surface 1a, more material of the buffer pad layer 7 can be embedded in the area between the third sub-surface 1cc3 and the third surface 8a, so that the material (for example, resin) of the buffer pad layer 7 embedded in the area between the third sub-surface 1cc3 and the third surface 8a can realize the function of connecting the edge of the circuit board 8 and the buffer pad layer 7, so that the edge of the circuit board 8 is better covered by the buffer pad layer 7; at the same time, the connection between the edge of the circuit board 8 and the buffer pad layer 7 is more reliable.

[0273] In some embodiments, as shown in FIG. 18 and FIG. 23, the back electrode 4 includes oppositely arranged sixth surface 4a and seventh surface 4b, and a plurality of third side surfaces 4c connecting the sixth surface 4a and the seventh surface 4b. The sixth surface 4a is closer to the circuit board 8 than the seventh surface 4b. The plurality of third side surfaces 4c includes a selected third side surface 4cc; the selected third side surface 4cc corresponds to a selected second side surface 8cc. The buffer pad layer 7 also covers the junction K2 between the seventh surface 4b and the selected third side surface 4cc of the back electrode 4. The part of the buffer pad layer 7 on the side of the seventh surface 4b has a dimension (hereinafter referred to as second dimension L2) in the first direction X ranging from 0 to 200 μm, and the first direction X is the extension direction of the third part 33 of the connecting lead 3.

[0274] Here, as to the understanding of the correspondence between the selected third side surface 4cc and the selected second side surface 8cc, reference can be made to the foregoing exemplary description of the correspondence between the selected third side surface 4cc and the selected second side surface 8cc, which will not be repeated here.

[0275] Exemplarily, the second dimension L2 can be 0 μm, 30 μm, 60 μm, 90 μm, 120 μm, 150 μm, 175 μm or 200 μm, etc. It should be noted that the second dimension L2 can be 0 μm, that is, as shown in FIG. 1, the second boundary 7B of the buffer pad layer 7 can be located at the junction of the seventh surface 4b and the selected third side surface 4cc. In actual applications, the second dimension L2 can be determined according to parameters such as materials and process control capabilities.

[0276] It can be understood that, as described above, when the buffer pad layer 7 also covers the junction K2 of the seventh surface 4b and the selected third side surface 4cc of the back electrode 4, the buffer pad layer 7 also covers the second gap G2 (see FIG. 13), at this time, a part of the material of the buffer pad layer 7 can be filled in the region of the second gap G2 close to the second selected side surface 8cc; that is, the buffer pad layer 7 integrates the first gap G1 and the second gap G2 into a gentle slope; in this way, when the third part 33 of the connecting lead 3 is formed, the connecting lead 3 can be formed on the side of the buffer pad layer 7 away from the fourth surface 8b, in this way, compared with the case where the buffer pad layer 7 does not cover the second gap G2, the abruptness of the surface of the third part 33 of the connecting lead 3 in the third direction Z can be reduced, the topography difference of the third part 33 of the connecting lead 3 can be reduced, the disconnection of the connecting lead 3 can be prevented, the conducting line formed by the connecting lead 3 can be more stable, and the connecting lead 3 can meet the line resistance requirement. Moreover, when the second dimension L2 is large (for example, greater than 200 μm), it can cause waste of the material of the buffer pad layer 7 and the material of the connecting lead 3. Therefore, by setting the second dimension L2 in the range of 0-200 μm, the waste of the material of the buffer pad layer 7 and the material of the connecting lead 3 can be avoided.

[0277] In some embodiments, as shown in FIG. 24, the back electrode 4 includes a sixth surface 4a and a seventh surface 4b oppositely arranged, and a plurality of third side surfaces 4c connecting the sixth surface 4a and the seventh surface 4b. The sixth surface 4a is closer to the circuit board 8 than the seventh surface 4b. The plurality of third side surfaces 4c includes a selected third side surface 4cc; the selected third side surface 4cc corresponds to a selected second side surface 8cc. The second boundary 7B is located on the fourth surface 8b and between the selected third side surface 4cc and the second selected side surface 8cc. The second boundary 7B is spaced apart from the selected third side surface 4cc by a seventh distance D7 in the first direction X, which is the extending direction of the third portion 33 of the connecting lead 3, and the seventh distance D7 ranges from 50 μm to 250 μm.

[0278] Exemplarily, the seventh distance D7 can be 50 μm, 80 μm, 110 μm, 140 μm, 170 μm, 215 μm, or 250 μm, etc. For example, the seventh distance D7 in FIG. 24 can be 150 μm.

[0279] It can be understood that when the seventh distance D7 is smaller, the distance between the second boundary 7B and the selected third side surface 4cc is smaller, so that among the surfaces forming the connecting lead 3, the part between the second boundary 7B and the seventh surface 4b has a larger change in topography; in this way, when the material of the connecting lead 3 adheres to the area between the second boundary 7B and the selected third side surface 4cc, the third portion 33 of the connecting lead 3 formed has a larger difference in topography. Therefore, by setting the seventh distance D7 to range from 50 μm to 250 μm, the difference in topography of the surface of the third portion 33 of the connecting lead 3 can be reduced, and the difference in topography of the third portion 33 of the connecting lead 3 can be reduced.

[0280] In some embodiments, as shown in FIG. 24, the intersection of the selected first side surface 1cc and the second surface 1b is a first reference edge H1. The surface of the cushion layer 7 away from the second surface 1b of the substrate 1 is a fifth surface 7a. The cross section of the fifth surface 7a perpendicular to the first reference edge H1 is a first line segment H2, and the size of the first line segment H2 ranges from 300 μm to 1000 μm.

[0281] As described above, the first line segment H2 can be a curved segment, of course, the first line segment H2 can also be a straight segment, which is not limited here. Here, the size of the first line segment H2 refers to the size of the first line segment H2 in the extending direction thereof.

[0282] Exemplarily, the size of the first line segment H2 can be 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 720 μm, 800 μm, 900 μm, or 1000 μm, etc. In actual applications, the size of the first line segment H2 can be determined according to the distance between the circuit board 8 and the selected first side surface 1cc, etc.

[0283] It can be understood that when the size of the first line segment H2 ranges from 300 μm to 1000 μm, it can be more matched with the size of the circuit board 8, the size of the back electrode 4, and the size of the substrate 1, so that the buffer pad layer 7 can realize the function of reducing the morphology difference.

[0284] In some embodiments, as shown in FIGS. 35 and 36, the fourth surface 8b is parallel to the second surface 1b, and at this time, the distance between the fourth surface 8b and the second surface 1b is equal everywhere.

[0285] In some embodiments, as shown in FIGS. 37 and 38, in the portion of the fourth surface 8b close to the selected second side surface 8cc, along the direction X1 of the selected second side surface 8cc pointing to the selected first side surface 1cc, the distance (hereinafter referred to as the eighth distance D8) between the fourth surface 8b and the second surface 1b gradually decreases.

[0286] Here, the direction X1 of the selected second side surface 8cc pointing to the selected first side surface 1cc is parallel to the first direction X and is the direction of the selected second side surface 8cc pointing to the selected first side surface 1cc.

[0287] It should be understood that through the above arrangement, the portion of the fourth surface 8b close to the selected second side surface 8cc is not parallel to the second surface 1b, and along the direction X1 of the selected second side surface 8cc pointing to the selected first side surface 1cc, it gradually bends towards the direction close to the second surface 1b. Moreover, when the bending portion of the fourth surface 8b is provided with the back electrode 4 on one side, the change trend of the back electrode 4 can be consistent with the change trend of the fourth surface 8b, that is, the back electrode 4 can be parallel to the circuit board 8.

[0288] Here, the shape of the portion of the fourth surface 8b close to the selected second side surface 8cc is not limited. For example, the portion of the fourth surface 8b close to the selected second side surface 8cc can be a bevel; for another example, the portion of the fourth surface 8b close to the selected second side surface 8cc can be a curved surface; and when it is a curved surface, the bending direction of the curved surface is, for example, the direction towards the second surface 1b.

[0289] It can be understood that, by the above arrangement, the height of the first step difference G1 in the third direction Z (see FIG. 13) can be reduced, so that, compared with the case where the portion of the fourth surface 8b close to the selected second side surface 8cc is parallel to the second surface 1b, the abrupt step difference of the surface forming the cushion pad layer 7 in the third direction Z can be reduced, the material (e.g., resin) of the cushion pad layer 7 can slowly climb when the cushion pad layer 7 is formed, and the process feasibility when the cushion pad layer 7 is formed can be improved.

[0290] Hereinafter, the manner in which the distance (eighth distance D8) between the portion of the fourth surface 8b close to the selected second side surface 8cc and the second surface 1b gradually decreases will be exemplarily described.

[0291] In some embodiments, as shown in FIGS. 37 and 38, the circuit board 8 includes an adhesive layer 81 and a carrier body 82 arranged in a stack. The adhesive layer 81 is close to the substrate 1 relative to the carrier body 82.

[0292] It should be understood that, when the adhesive layer 81 is close to the substrate 1 relative to the carrier body 82, the adhesive layer 81 can be located between the carrier body 82 and the substrate 1, achieving the effect of connecting the carrier body 82 close to the substrate 1. Moreover, in the case where the circuit board 8 includes the adhesive layer 81 and the carrier body 82, the surface of the carrier body 82 away from the adhesive layer 81 is the fourth surface 8b of the circuit board 8; the side surface of the carrier body 82 corresponding to the selected first side surface 1cc and the side surface of the adhesive layer 81 corresponding to the selected first side surface 1cc together constitute the selected second side surface 8cc of the circuit board 8.

[0293] In the case where the circuit board 8 includes the adhesive layer 81 and the carrier body 82, the eighth distance D8 gradually decreases. As a possible implementation manner, in the portion of the adhesive layer 81 close to the selected first side surface 1cc, the thickness of the adhesive layer 81 gradually decreases in the direction X1 of the selected second side surface 8cc pointing to the selected first side surface 1cc. In other words, the thickness of the portion of the adhesive layer 81 close to the selected first side surface 1cc can be gradually reduced in the direction X1. In this way, the eighth distance D8 can gradually decrease in the direction X1 of the selected second side surface 8cc pointing to the selected first side surface 1cc.

[0294] As another possible implementation manner, as shown in FIGS. 37 and 38, the distance (hereinafter referred to as ninth distance D9) between the carrier body 82 and the selected first side surface 1cc in the first direction X is less than the distance (hereinafter referred to as tenth distance D10) between the adhesive layer 81 and the selected first side surface 1cc in the first direction X, the first direction X being the extension direction of the third portion 33 of the lead 3.

[0295] It should be noted that when the selected first side surface 1cc includes the first sub-surface 1cc1, the second sub-surface 1cc2 and the third sub-surface 1cc3, the ninth distance D9 can be the distance between the carrier plate body 82 and the third sub-surface 1cc3 in the first direction X, and the tenth distance D10 can be the distance between the adhesive layer 81 and the third sub-surface 1cc3 in the first direction X.

[0296] It can be understood that when the ninth distance D9 is less than the tenth distance D10, the part of the carrier plate body 82 close to the selected first side surface 1cc is closer to the selected first side surface 1cc than the part of the adhesive layer 81 close to the selected first side surface 1cc; that is, the adhesive layer 81 can be made to be concave.

[0297] Through the above arrangement, on the one hand, the part of the carrier plate body 82 close to the selected first side surface 1cc and the substrate 1 can be filled with the material of the adhesive layer 81, the carrier plate body 82 can be bent towards the second surface 1b, the height of the first gap G1 in the third direction Z (see FIG. 13) can be reduced, as described above, the abrupt gap of the surface of the cushion pad layer 7 in the third direction Z can be reduced, and the process feasibility of forming the cushion pad layer 7 can be improved. On the other hand, the part of the carrier plate body 82 close to the selected first side surface 1cc and the substrate 1 can form a containing cavity, so that when the cushion pad layer 7 is formed, the material of the cushion pad layer 7 can enter the containing cavity, and the material of the cushion pad layer 7 located in the containing cavity can be used as the riveting structure F between the cushion pad layer 7 and the circuit board 8, the contact area between the cushion pad layer 7 and the circuit board 8 can be increased, and the connection between the cushion pad layer 7 and the circuit board 8 can be more reliable.

[0298] Exemplarily, the riveting structure F can be formed by making the material of the cushion pad layer 7 flow flat for a specific time and then solidifying to form the riveting structure F; or by printing at a specific angle and then solidifying to form the riveting structure F.

[0299] It should be noted that as shown in FIG. 36, when the fourth surface 8b is parallel to the second surface 1b, the riveting structure F can also be formed.

[0300] In some embodiments, the difference between the distance between the adhesive layer 81 and the selected first side surface 1cc in the first direction X (the tenth distance D10) and the distance between the carrier plate body 82 and the selected first side surface 1cc in the first direction X (the ninth distance D9) is less than or equal to 80 μm. That is, the difference between the tenth distance D10 and the ninth distance D9 is less than or equal to 80 μm.

[0301] Exemplarily, the difference between the tenth distance D10 and the ninth distance D9 can be 0 pm, 10 pm, 20 pm, 30 pm, 40 pm, 50 pm, 60 pm, 72 pm, or 80 pm, etc. It should be noted that the difference between the tenth distance D10 and the ninth distance D9 can be 0 pm, that is, the tenth distance D10 can be equal to the ninth distance D9.

[0302] It can be understood that when the difference between the tenth distance D10 and the ninth distance D9 is large, before the buffer pad layer 7 is formed, the support effect of the bonding layer 81 on the part of the carrier plate body 82 close to the selected first side surface 1cc is poor, and the connection effect between the part of the carrier plate body 82 close to the selected first side surface 1cc and the second surface 1b is poor. Therefore, by setting the difference between the tenth distance D10 and the ninth distance D9 to be less than or equal to 80 pm, the support effect of the bonding layer 81 on the part of the carrier plate body 82 close to the selected first side surface 1cc and the connection effect between the part of the carrier plate body 82 close to the selected first side surface 1cc and the second surface 1b can be improved.

[0303] In some embodiments, the intersection of the selected first side surface 1cc and the second surface 1b is a first reference edge H1. The cross section of the fourth surface 8b perpendicular to the first reference edge H1 is a second line segment H3. The included angle θ between the tangent of the second line segment H3 and the second surface 1b ranges from 0° to 15°.

[0304] Exemplarily, the included angle θ between the tangent of the second line segment H3 and the second surface 1b can be 0°, 3°, 6°, 9°, 10°, 12°, or 15°, etc. It should be noted that the included angle θ between the tangent of the second line segment H3 and the second surface 1b can be 0°, that is, the tangent of the second line segment H3 can be parallel to the second surface 1b.

[0305] It can be understood that when the included angle θ between the tangent of the second line segment H3 and the second surface 1b is large, the part of the carrier plate body 82 close to the selected first side surface 1cc is closer to the second surface 1b, so that when the buffer pad layer 7 is formed, it is more difficult for the material of the buffer pad layer 7 to enter the accommodation cavity, and the riveting structure F formed has a small effect on improving the connection effect between the buffer pad layer 7 and the circuit board 8; and when the material of the buffer pad layer 7 enters the accommodation cavity, air bubbles are easily generated, the buffer pad layer 7 is not filled enough in the accommodation cavity, and the connection reliability between the carrier plate body 82 and the substrate 1 and between the carrier plate body 82 and the buffer pad layer 7 can be affected. Therefore, by setting the included angle θ between the tangent of the second line segment H3 and the second surface 1b to range from 0° to 15°, the connection between the carrier plate body 82 and the substrate 1 and between the carrier plate body 82 and the buffer pad layer 7 can be more reliable.

[0306] In another aspect, as shown in FIGS. 39A and 39B, some embodiments of the present disclosure further provide a display device 100, comprising the display panel 10 and the driving circuit board 20 provided by any of the foregoing embodiments. The driving circuit board 20 is electrically connected to the display panel 10; for example, the driving circuit board 20 is electrically connected to the back surface electrode 4 of the display panel 10 through the flexible circuit board 9, and the electrical signal provided by the driving circuit board 20 is transmitted to the driving circuit layer of the display panel 10 via the flexible circuit board 9, the back surface electrode 4, the connecting lead 3 and the front surface electrode 2, so as to control the light-emitting device to emit light, and the driving circuit board 20 is configured to drive the display panel 10 to display an image.

[0307] The display device 100 can be any device that displays images, whether in motion (e.g., video) or still (e.g., a still image), text, or graphics. More particularly, it is contemplated that the embodiments can be implemented in or in association with a variety of electronic devices such as, but not limited to, mobile telephones, wireless devices, personal data assistants (PDAs), handheld or portable computers, GPS receivers / navigators, cameras, MP4 players, camcorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, computer monitors, auto displays (e.g., odometer display, etc.), cockpit controls and / or displays, camera view displays (e.g., display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projections, architectural structures, packaging, and aesthetic structures (e.g., display of images on a piece of jewelry), and the like.

[0308] Exemplarily, the display device 100 described above can further comprise a frame and other electronic accessories, etc. Wherein, the display panel 10 can be arranged in the frame, for example.

[0309] The display device 100 described above has the same beneficial effects as the display panel 10 described in some of the foregoing embodiments, which will not be repeated here.

[0310] In yet another aspect, as shown in FIGS. 41 and 43, some embodiments of the present disclosure further provide a tiled display device 1000, comprising a plurality of display devices 100 provided by any of the foregoing embodiments.

[0311] Exemplarily, as shown in FIGS. 41 and 43, the plurality of display devices 100 in the tiled display device 1000 are arranged in an array.

[0312] Exemplarily, as shown in FIGS. 41 and 43, the display device 100 is rectangular, for example.

[0313] As shown in FIG. 40 and FIG. 42, in the display panel 10, the plurality of front electrodes 2 are arranged in parallel and spaced apart along the second direction Y, and correspondingly, the plurality of connecting leads 3 are also arranged in parallel and spaced apart along the second direction Y, and the fourth direction E is another direction parallel to the display device 100 and perpendicular to the second direction Y. The display device 100 includes a plurality of sides, and hereinafter, the side of the display device 100 close to the plurality of front electrodes 2 is referred to as the selected side of the display device 100.

[0314] Exemplarily, as shown in FIG. 40, the display panel 10 includes a display area AA and two electrode connecting areas BB located on opposite sides of the display area AA, and the display panel 10 includes two groups of front electrodes 2, each group of front electrodes 2 includes a plurality of front electrodes 2, and the two groups of front electrodes 2 are respectively close to the two electrode connecting areas BB.

[0315] Exemplarily, as shown in FIG. 41, when a plurality of display devices 100 including the display panel 10 shown in FIG. 40 are spliced, the selected sides of the adjacent two display devices 100 are both arranged along the second direction Y, so that in the plurality of display devices 100 arranged in a row along the second direction Y, there is substantially no splicing gap between the adjacent two display devices 100 along the second direction Y; in the plurality of display devices 100 arranged in a column along the fourth direction E, there is a splicing gap between the adjacent two display devices 100, that is, in the plurality of display devices 100 arranged in a row along the second direction Y, the size of the splicing gap between the adjacent two display devices 100 is smaller than the size of the splicing gap between the adjacent two display devices 100 arranged in a column along the third direction Z.

[0316] However, the size of the electrode connecting area BB in the fourth direction E is small, so that when the spliced display device 1000 is actually viewed, the splicing gap between the adjacent two display devices 100 is relatively difficult to be found by the naked eye within the viewing distance, so that the display picture of the spliced display device 1000 is relatively complete, and a better display effect can be presented.

[0317] Exemplarily, as shown in FIG. 42, the display panel 10 includes a display area AA and an electrode connecting area BB located on one side of the display area AA, and the plurality of front electrodes 2 are arranged in the electrode connecting area BB.

[0318] Exemplarily, as shown in FIG. 43, when the plurality of display devices 100 including the display panel 10 as shown in FIG. 42 are spliced, the selected side of each of the two adjacent display devices 100 is arranged along the second direction Y, so that among the plurality of display devices 100 arranged in a row along the second direction Y, there is substantially no splicing gap between the two adjacent display devices 100 along the second direction Y; among the plurality of display devices 100 arranged in a column along the third direction Z, there is a splicing gap between the two adjacent display devices 100, that is, among the plurality of display devices 100 arranged in a row along the second direction Y, the size of the splicing gap between the two adjacent display devices 100 is smaller than the size of the splicing gap between the two adjacent display devices 100 arranged in a column along the third direction Z.

[0319] However, the size of the electrode connection region BB in the fourth direction E is small, so that the splicing gap between the two adjacent display devices 100 is difficult to be found by naked eyes within a viewing distance when the spliced display device 1000 is actually viewed, so that the display screen of the spliced display device 1000 is relatively complete, and a better display effect can be presented.

[0320] The beneficial effects of the spliced display device 1000 described above are the same as those of the display device 100 described in some of the above embodiments, which will not be repeated here.

[0321] The above merely describes specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art who thinks of changes or replacements within the technical scope disclosed by the present disclosure should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A display panel, comprising: a substrate comprising a first surface and a second surface oppositely arranged, and a plurality of first side surfaces connecting the first surface and the second surface; the plurality of first side surfaces comprises at least one selected first side surface; a circuit board arranged on the second surface; the circuit board comprises a third surface and a fourth surface oppositely arranged, and a plurality of second side surfaces connecting the third surface and the fourth surface; the third surface is closer to the substrate than the fourth surface; the plurality of second side surfaces comprises at least one selected second side surface; each selected second side surface corresponds to one selected first side surface; a buffer pad layer located on a side of the circuit board close to the selected first side surface, and at least covering the junction of the fourth surface and the selected second side surface of the circuit board; a plurality of back electrodes arranged side by side and spaced apart on the fourth surface; and a plurality of connection leads arranged side by side and spaced apart; each connection lead comprises a first part located on a side of the first surface, a second part located on a side of the selected first side surface, and a third part located on a side of the second surface; the third part of each connection lead is electrically connected to one back electrode; the third part of the connection lead comprises a part located on the buffer pad layer; wherein the ratio between the maximum value of the line width of the third part of the connection lead and the minimum value of the line width of the third part of the connection lead ranges from 1.0 to 1.5, and the line width of the third part of the connection lead is the dimension of the third part of the connection lead in the direction perpendicular to the extension direction of the third part of the connection lead.

2. The display panel of claim 1, wherein, The buffer pad layer comprises a first boundary and a second boundary, the first boundary and the second boundary are arranged in a first direction in the orthographic projection of the second surface; the first boundary is farther away from the back electrode than the second boundary in the first direction; The first direction is the extension direction of the third part of the connection lead; The third part of the connection lead comprises a first position, the first position is located on the side of the first boundary away from the second boundary, and the distance between the first position and the first boundary in the first direction ranges from 50 μm to 200 μm; the line width of the third part of the connection lead gradually increases from the first position to the first boundary.

3. The display panel of claim 2, wherein, The line width of the third part of the connection lead reaches a first maximum line width at a second position, the second position is located between the first boundary and the second boundary, and the distance between the second position and the first boundary in the first direction ranges from 0 to 600 μm.

4. The display panel of claim 3, wherein, The ratio between the first maximum line width and the line width of the third part of the connection lead at the first position ranges from 1.0 to 1.

5.

5. The display panel of claim 3 or 4, wherein, The intersection line of the selected first side surface and the second surface is a first reference edge; the cross section of the buffer pad layer perpendicular to the first reference edge is a second cross section, in which the distance between the surface of the buffer pad layer away from the second surface and the second surface of the substrate gradually increases from the first boundary to a third position, and gradually decreases from the third position to the second boundary; the third position is between the second position and the second boundary; The line width of the third part of the connecting lead wire reaches a minimum line width at a fourth position, the fourth position is between the third position and the second boundary, and the distance range between the fourth position and the second boundary in the first direction is 0-400 μm.

6. The display panel of claim 5, wherein, The ratio between the minimum line width and the line width of the third part of the connecting lead wire at the first position ranges from 1.0 to 1.

5.

7. The display panel according to any one of claims 2 to 6, wherein The line width of the third part of the connecting lead wire reaches a second maximum line width at a fifth position, the fifth position is on the side of the second boundary away from the first boundary, and the distance range between the fifth position and the second boundary in the first direction is 0-150 μm.

8. The display panel of claim 7, wherein, In the case where the line width of the third part of the connecting lead wire reaches a first maximum line width at the second position, the second maximum line width is less than or equal to the first maximum line width.

9. The display panel of claim 7 or 8, wherein, The ratio between the second maximum line width and the line width of the third part of the connecting lead wire at the first position ranges from 1.0 to 1.

5.

10. The display panel according to any one of claims 7 to 9, wherein The third part of the connecting lead wire further includes a sixth position, the sixth position is on the side of the fifth position away from the second boundary, and the distance range between the sixth position and the second boundary in the first direction is 50-200 μm; the line width of the third part of the connecting lead wire gradually decreases from the fifth position to the sixth position.

11. The display panel according to any one of claims 2 to 10, wherein The first boundary is on the second surface; The line width of the third part of the connecting lead wire reaches a third maximum line width at a seventh position, the seventh position is on the second surface and the distance range between the seventh position and the selected first side surface is 50-150 μm.

12. The display panel of claim 11, wherein, In the case where the line width of the third part of the connecting lead wire reaches a first maximum line width at the second position, the third maximum line width is less than or equal to the first maximum line width.

13. The display panel of claim 11 or 12, wherein, The ratio between the third maximum line width and the line width of the third part of the connecting lead wire at the first position ranges from 1.0 to 1.

5.

14. The display panel according to any one of claims 11 to 13, wherein, The intersection line of the selected first side surface and the second surface is a first reference edge; the surface of the buffer pad layer away from the second surface of the substrate is a fifth surface, the cross section of the fifth surface perpendicular to the first reference edge is a first line segment, the first line segment is a curved segment, and the included angle between the tangent of the first line segment and the second surface ranges from 0° to 40°.

15. The display panel according to any one of claims 2 to 10, wherein, The first boundary is on the selected first side surface; The size of the part of the selected first side surface covered by the buffer pad layer in the direction perpendicular to the first reference edge ranges from 0 to 30 μm; the first reference edge is the intersection line of the selected first side surface and the second surface.

16. The display panel according to any one of claims 1 to 15, wherein, The selected first side surface comprises: a first sub-surface parallel to the first reference edge and perpendicular to the first surface; the first reference edge is the intersection line of the selected first side surface and the second surface; a second sub-surface between the first sub-surface and the first surface and in the form of an inclined surface; a third sub-surface between the first sub-surface and the second surface and in the form of an inclined surface; the angle between the second sub-surface and the first surface ranges from 110° to 160°; and / or, the angle between the third sub-surface and the second surface ranges from 110° to 160°.

17. The display panel of claim 16, wherein, Further comprising: a plurality of front electrodes arranged in parallel and spaced apart on the first surface; each front electrode corresponds to a back electrode; wherein the first boundary is located on one side of the first surface and in contact with the plurality of front electrodes.

18. The display panel of claim 16 or 17, wherein, The back electrode comprises a sixth surface and a seventh surface arranged oppositely, and a plurality of third side surfaces connecting the sixth surface and the seventh surface; the sixth surface is closer to the circuit board relative to the seventh surface; The plurality of third side surfaces comprises a selected third side surface; the selected third side surface corresponds to a selected second side surface; The corresponding selected second side surface and selected third side surface are flush; the selected second side surface and the selected third side surface are located on the side of the first reference edge away from the second surface; The angle between the third sub-surface and the second surface is less than or equal to the angle between the second sub-surface and the first surface; the material of the buffer pad layer is embedded in the area between the third sub-surface and the third surface.

19. The display panel according to any one of claims 1 to 18, wherein The back electrode comprises a sixth surface and a seventh surface arranged oppositely, and a plurality of third side surfaces connecting the sixth surface and the seventh surface; The sixth surface is closer to the circuit board relative to the seventh surface; The plurality of third side surfaces comprises a selected third side surface; the selected third side surface corresponds to a selected second side surface; The buffer pad layer also covers the junction between the seventh surface of the back electrode and the selected third side surface; The part of the buffer pad layer on the side of the seventh surface has a dimension in the first direction ranging from 0 to 200 μm, and the first direction is the extension direction of the third part of the connecting lead.

20. The display panel according to any one of claims 1 to 18, wherein The back electrode comprises a sixth surface and a seventh surface arranged oppositely, and a plurality of third side surfaces connecting the sixth surface and the seventh surface; The sixth surface is closer to the circuit board relative to the seventh surface; The plurality of third side surfaces comprises a selected third side surface; the selected third side surface corresponds to a selected second side surface; The second boundary is located on the fourth surface and between the selected third side surface and the second selected side surface; The distance between the second boundary and the selected third side surface in the first direction ranges from 50 μm to 250 μm, and the first direction is the extension direction of the third part of the connecting lead.

21. The display panel according to any one of claims 1 to 20, wherein, An intersection line of the selected first side surface and the second surface is a first reference edge; a surface of the buffer pad layer away from the second surface of the substrate is a fifth surface, a cross section of the fifth surface perpendicular to the first reference edge is a first line segment, and a size of the first line segment ranges from 300 μm to 1000 μm.

22. The display panel of any one of claims 1-21, wherein, In a portion of the fourth surface close to the selected second side surface, a distance between the fourth surface and the second surface gradually decreases in a direction of the selected second side surface pointing to the selected first side surface.

23. The display panel of claim 22, wherein, The circuit board comprises a bonding layer and a carrier body arranged in a stack, and the bonding layer is close to the substrate relative to the carrier body. A spacing between the carrier body and the selected first side surface in a first direction is smaller than a spacing between the bonding layer and the selected first side surface in the first direction, and the first direction is an extension direction of the third part of the connection lead.

24. The display panel of claim 23, wherein, A difference between the spacing between the bonding layer and the selected first side surface in the first direction and the spacing between the carrier body and the selected first side surface in the first direction is less than or equal to 80 μm.

25. The display panel of any one of claims 22-24, wherein, An intersection line of the selected first side surface and the second surface is a first reference edge; a cross section of the fourth surface perpendicular to the first reference edge is a second line segment, and an included angle between a tangent of the second line segment and the second surface ranges from 0° to 15°.

26. A method for manufacturing a display panel, comprising: providing a substrate; the substrate comprises a first surface and a second surface arranged oppositely, and a plurality of first side surfaces connecting the first surface and the second surface; the plurality of first side surfaces comprises at least one selected first side surface; forming a circuit board on the second surface; the circuit board comprises a third surface and a fourth surface arranged oppositely, and a plurality of second side surfaces connecting the third surface and the fourth surface; the third surface is close to the substrate relative to the fourth surface; the plurality of second side surfaces comprises at least one selected second side surface; each selected second side surface corresponds to one selected first side surface; forming a plurality of back electrodes on the fourth surface; the plurality of back electrodes are arranged side by side and spaced apart on the fourth surface; forming a buffer pad layer on a side of the circuit board close to the selected first side surface, the buffer pad layer at least covers a junction between the fourth surface of the circuit board and the selected second side surface; and forming a plurality of connection leads; the plurality of connection leads are arranged side by side and spaced apart; each connection lead comprises a first part on a side of the first surface, a second part on a side of the selected first side surface, and a third part on a side of the second surface; the third part of each connection lead is electrically connected to one back electrode; the third part of the connection lead comprises a portion on the buffer pad layer; wherein a ratio between a maximum value of a line width of the third part of the connection lead and a minimum value of the line width of the third part of the connection lead ranges from 1 to 1.5, and the line width of the third part of the connection lead is a size of the third part of the connection lead in a direction perpendicular to an extension direction of the third part of the connection lead.

27. A display device comprising: a display panel according to any one of claims 1 to 25; a drive circuit board electrically connected to the display panel; the drive circuit board configured to drive the display panel to display an image.

28. A tiled display device comprising a plurality of display devices according to claim 27.

Images