Display panel and display device

Abstract

The embodiment of the invention discloses a display panel and a display device. The display panel comprises an array substrate. The array substrate further comprises a substrate and a circuit layer located on the surface of one side of the substrate. The first region comprises a plurality of signal lines, and the signal lines extend to the second region; the second region comprises a plurality of lead-out bonding pad units, each lead-out bonding pad unit comprises a first bonding pad structure, and the first bonding pad structures are located on the surface, deviating from the substrate, of the circuit layer in the second region; the first bonding pad structure is electrically connected with the signal line; the plurality of first bonding pad structures comprise first sub-bonding pad structures and second sub-bonding pad structures; the first sub-pad structure and the second sub-pad structure are made of different materials. According to the embodiment of the invention, the problem of poor transmission of driving signals caused by stripping or falling of the bonding pad structure is solved, normal and effective lead-out bonding pad unit connection of each signal line can be ensured, transmission of external driving signals is realized, and normal display of the display panel can be realized.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of display technologies, and in particular, to a display panel and a display device. Background Art

[0002] With the continuous development of science and technology, more and more electronic devices with display functions are widely used in people's daily lives and work, bringing great convenience to people's daily lives and work, and becoming an indispensable important tool for people today.

[0003] Generally, a display panel needs to be provided with lead-out pads in the edge area of the display panel, and the lead-out pads are used to connect to an external driving unit to receive a driving signal provided externally to achieve a display function. However, due to the reason of process yield, the lead-out pads located in the edge area of the display panel are prone to problems such as peeling and falling off in subsequent manufacturing processes, resulting in the driving signal being unable to effectively input to the display panel through the lead-out pads, causing poor signal transmission and affecting the normal operation of the display function. Summary of the Invention

[0004] The present invention provides a display panel and a display device to make up for the problem of poor signal transmission caused by peeling of the lead-out pads and ensure the normal operation of the display function.

[0005] In a first aspect, an embodiment of the present invention provides a display panel, including an array substrate, where the array substrate includes a first area and a second area connected to the first area; the array substrate further includes a substrate and a circuit layer located on one surface of the substrate; the circuit layer has a height difference in a direction perpendicular to the array substrate between a surface facing away from the substrate in the first area and a surface facing away from the substrate in the second area;

[0006] The first area includes a plurality of signal lines, and the signal lines extend to the second area;

[0007] The second area includes a plurality of lead-out pad units, and each lead-out pad unit includes a first pad structure, and the first pad structure is located on a surface of the circuit layer facing away from the substrate in the second area; the first pad structure is electrically connected to the signal line;

[0008] The plurality of first pad structures include a first sub-pad structure and a second sub-pad structure; the materials of the first sub-pad structure and the second sub-pad structure are different.

[0009] In a second aspect, an embodiment of the present invention further provides a display device, including any display panel provided by the embodiment of the present invention.

[0010] In the technical solution of the embodiment of the present invention, a first region and a second region are provided on the array substrate. An extraction pad unit is provided in the second region. The extraction pad unit is connected to a signal line provided in the first region. Moreover, the extraction pad unit has a first pad structure exposed on the surface of the second region facing away from the substrate. The first pad structure is prepared by two processes. First, the first pad structure is prepared to form a plurality of first sub-pad structures. And after the first sub-pad structure peels off or falls off, the first pad structure is prepared again at the same position by other processes to form a second sub-pad structure made of a material different from that of the first sub-pad structure. In this way, the problem of poor transmission of driving signals caused by the peeling off or falling off of the pad structure can be solved, ensuring that each signal line can be normally and effectively connected to the extraction pad unit, realizing the transmission of external driving signals, and enabling the display panel to display normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic structural diagram of a display panel in the related art;

[0012] Figure 2 is Figure 1 a schematic cross-sectional view of the area within the dashed box in the display panel;

[0013] Figure 3 is a schematic structural diagram of a display panel provided by an embodiment of the present invention;

[0014] Figure 4 is Figure 3 a schematic cross-sectional view of the display panel shown along AA';

[0015] Figure 5 is Figure 3 a schematic cross-sectional view of the display panel shown along BB';

[0016] Figure 6 is a partial enlarged view of a display panel provided by an embodiment of the present invention;

[0017] Figure 7 is a partial enlarged view of another display panel provided by an embodiment of the present invention;

[0018] Figure 8 is a partial enlarged view of yet another display panel provided by an embodiment of the present invention;

[0019] Figure 9 and Figure 10 is Figure 3 two other schematic cross-sectional views of the display panel shown along AA' and BB' respectively;

[0020] Figure 11 and Figure 12 are two schematic cross-sectional views of different positions of another display panel provided by an embodiment of the present invention;

[0021] Figure 13 is a schematic cross-sectional view of another display panel provided by an embodiment of the present invention;

[0022] Figure 14 is a schematic cross-sectional view of another display panel provided by an embodiment of the present invention;

[0023] Figure 15 and Figure 16 are schematic structural views of two display devices provided by an embodiment of the present invention. Detailed implementation manners

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0025] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the orientation terms such as "upper", "lower", "left", and "right" described in the embodiments of the present invention are described from the perspective shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also be indirectly formed "on" or "under" another element through an intermediate element. The terms "first", "second", etc. are only used for descriptive purposes, and do not represent any order, quantity, or importance, but are only used to distinguish different components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] The term "including" and its variants used in the present invention are open-ended, that is, "including but not limited to". The term "based on" is "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0027] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish the corresponding content, and are not used to limit the order or the interdependent relationship.

[0028] It should be noted that the modification of "one" and "multiple" mentioned in the present invention is illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly specified in the context, it should be understood as "one or more".

[0029] Figure 1 is a schematic structural view of a display panel in the related art, Figure 2 isFigure 1 Schematic cross-sectional view of the area within the dashed box in the shown display panel, refer to Figure 1 and Figure 2 , first, to explain the problem that the lead pads on the display panel are prone to peeling as described in the background art section, here, a borderless tiled display panel is taken as an example for illustration. The tiled display panel means that at least two display panels can be tiled with each other to expand the display area and form a tiled display. Specifically, for the tiled display panel, to drive the light-emitting elements (not shown in the figure) in the panel to emit light and implement the display function, an external driving unit (not shown in the figure), such as a display driving chip, etc., is required to provide corresponding driving signals. When setting up the connection to the external driving unit on the display panel, in the related art, it is considered to minimize the area of the front side of the display panel used for display as much as possible and reduce the border, so that there are no obvious tiling marks on the tiled display panel. Therefore, the signal line 100' connected to the light-emitting elements is led out to the edge area of the front side to form a lead pad 200', and then a side-walk line 400' is prepared. One end is connected to the lead pad 200' in the front edge area and extends to the back side through the side of the display panel, and the other end is connected to the external driving unit on the back side of the display panel, thereby reducing the border area on the front side of the tiled display panel and realizing a borderless tiled display panel.

[0030] Continue to refer to Figure 2 , the lead pad 200' provided in the front edge area of the tiled display panel has a part exposed on the surface for connecting the side-walk line 400'. This exposed part is formed by the top metal layer Mtop in the array substrate. In other words, when preparing the top metal layer Mtop of the array substrate, a pad structure 210' is formed synchronously in the edge area, that is, the exposed part of the lead pad 200'. It can be understood that since this exposed part is formed on the surface of the array substrate 10', its adhesion to the surface of the array substrate 10' is limited, resulting in the phenomenon that the pad structure 210' peels off or falls off, making the side-walk line 400' unable to be effectively connected to the lead pad 200', that is, the driving signal cannot be provided to the display panel through the external driving unit, causing some light-emitting elements not to be lit and affecting the normal display function.

[0031] In view of the above technical problems, an embodiment of the present invention provides a display panel. Figure 3 Schematic structural view of a display panel provided by an embodiment of the present invention, Figure 4 is Figure 3 Schematic cross-sectional view of the shown display panel at AA', Figure 5 is Figure 3 Schematic cross-sectional view of the shown display panel at BB', refer to Figures 3 - 5, the display panel includes an array substrate 10, and the array substrate 10 includes a first region A1 and a second region A2 connected to the first region A1; the array substrate 10 further includes a substrate 11 and a circuit layer 12 located on one surface of the substrate 11; the surface of the circuit layer 12 facing away from the substrate 11 in the first region A1 and the surface of the circuit layer 12 facing away from the substrate 11 in the second region A2 have a height difference in the direction perpendicular to the array substrate 10.

[0032] The first region A1 includes a plurality of signal lines 100, and the signal lines 100 extend to the second region A2; the second region A2 includes a plurality of lead pad units 200, and the lead pad unit 200 includes a first pad structure 210, and the first pad structure 210 is located on the surface of the circuit layer 12 facing away from the substrate 11 in the second region A2; the first pad structure 210 is electrically connected to the signal line 100; the plurality of first pad structures 210 include a first sub-pad structure 211 and a second sub-pad structure 212; the materials of the first sub-pad structure 211 and the second sub-pad structure 212 are different.

[0033] Among them, the first region A1 and the second region A2 are two regions on the array substrate 10 where different functional structures are arranged. Specifically, the first region A1 can be understood as a display region, which mainly exists in the central region of the display panel and is responsible for arranging light-emitting elements such as micro light-emitting diodes (Micro-LEDs). Light-emitting elements of different colors can form pixel units, thereby realizing the display function. The second region A2 can be understood as the region outside the first region A1, which mainly exists at the edge of the display panel and is used to arrange other auxiliary structures for driving the light-emitting elements in the first region A1 to emit light, such as pads, etc., which can be connected to the outside to receive driving signals provided by the outside. In addition, it should also be understood that the array substrate 10 is composed of a substrate 11 and a circuit layer 12 located on the substrate 11. The substrate 11 can be a flexible substrate such as a polyimide film, or a rigid substrate such as glass. The circuit layer 12 is used to form a pixel circuit array, and the pixel circuit is connected to the corresponding light-emitting element and is responsible for driving the corresponding light-emitting element to emit light.

[0034] It can be understood that the pixel circuit needs to be driven by an external signal. Therefore, signal lines 100 and lead pad units 200 need to be provided in the circuit layer 12 to connect to an external driving unit and receive the driving signal provided by the outside. Specifically, refer to Figures 3 - 5It can be seen that a plurality of signal lines 100 are provided in the first region A1. The signal lines 100 can specifically be data signal lines, scan signal lines, clock signal lines, power supply voltage signal lines, etc., and there is no limitation here. An extraction pad unit 200 is provided in the second region A2. As the name implies, the function of the extraction pad unit 200 is to lead out the signal lines 100 in the first region A1 to the edge region of the display panel, so as to facilitate bonding with an external driving unit such as a display driving chip, or to facilitate bonding with a connection structure such as a side connection trace, and then connect to the external driving unit through the connection structure.

[0035] It should be noted here that the structural form of the extraction pad unit 200 may not be limited to a two-dimensional planar structure of a single metal layer, and it may also be a three-dimensional structure formed by connecting multiple metal layers. In the extraction pad unit 200 of the embodiment of the present invention, there is a first pad structure 210 located on the surface of the second region A2, indicating that the first pad structure 210 is exposed on the surface of the second region A2. The first pad structure 210 is the part of the extraction pad unit 200 that can be bonded or connected to an external driving unit or a connection structure. Further, in the embodiment of the present invention, the first pad structure 210 is provided to include a first sub-pad structure 211 and a second sub-pad structure 212, and the materials of the first sub-pad structure 211 and the second sub-pad structure 212 are different, indicating that during the process of preparing the first pad structure 210, two first pad structures 210 with different materials will be formed. And, in essence, after the first pad structure 210 is initially prepared and formed, since the first pad structure 210 is exposed on the surface of the second region A2, some of the first pad structures 210 will peel off or fall off. After determining the position of the peeled-off or fallen-off first pad structure 210 through optical detection, the first pad structure 210 will be re-prepared to make up for the problem of the loss of the first pad structure 210 prepared initially. Since the peeling-off or falling-off phenomenon of the first pad structure 210 can only be discovered in subsequent processes and is restricted by the process flow and cannot use the process of initial preparation to prepare the first pad structure 210 again, the processes and materials used for the first pad structure 210 prepared twice at the same position will be different. Or rather, the processes and materials used for re-preparing the first pad structure 210 cannot be the same as those of the initial preparation process and materials. Thus, two first pad structures 210 with different materials are formed in the second region A2, namely the first sub-pad structure 211 and the second sub-pad structure 212. Exemplarily, the first sub-pad structure 211 can be formed by a thermal deposition process to form a first sub-pad structure 211 with a material of Ti / Cu / Ti or Al / Mo / Al; the second sub-pad structure 212 can be prepared by a chemical vapor deposition process in cooperation with laser scanning to form a second sub-pad structure 212 with a material of tungsten metal.

[0036] In the above technical solution, a first region and a second region are provided on the array substrate. An extraction pad unit is provided in the second region. The extraction pad unit is connected to a signal line provided in the first region. Moreover, the extraction pad unit has a first pad structure exposed on the surface of the second region facing away from the substrate. The first pad structure is fabricated by two processes. In the first process of fabricating the first pad structure, a plurality of first sub-pad structures are formed. And when the first sub-pad structures are peeled off or fall off, the first pad structure is fabricated again at the same position by other processes to form second sub-pad structures made of a material different from that of the first sub-pad structures, thereby solving the problem of poor transmission of drive signals caused by peeling off or falling off of the pad structure, ensuring that each signal line can be normally and effectively connected to the extraction pad unit, realizing the transmission of external drive signals, and enabling the display panel to display normally.

[0037] It should be supplemented and explained that the light-emitting elements and the extraction pad units 200 of the array substrate 10 are respectively distributed in the first region A1 and the second region A2. And the second region A2 is mainly used for bonding with the outside or connecting other connection structures such as side routing. Therefore, there is a height difference between the surfaces of the first region A1 and the second region A2. The surface of the second region A2 is lower than the surface of the first region A1, thereby ensuring that there is sufficient longitudinal space on the surface of the second region A2 for bonding or connecting other structures. Specifically, the formation of this height difference is mainly controlled by the insulating layer 300. As Figure 4 and Figure 5 shown, in the first region A1 and the second region A2, there are differences in the number of layers or the thickness of the insulating layer 300 in the circuit layer 12, such that the surface on the side facing away from the substrate 11 in the first region A1 is higher, while the surface on the side facing away from the substrate 11 in the second region A2 is relatively lower, thereby forming a height difference, saving the longitudinal space of the second region A2, and enabling other structures to be bonded and accommodated on the extraction pad unit 200 provided in the second region A2.

[0038] Continuing to refer to Figures 3 - 5 FIG., further, in the embodiment of the present invention, the extraction pad unit 200 further includes a second pad structure 220. The first pad structure 210 and the second pad structure 220 are located in different film layers and an insulating layer 300 is provided therebetween. A via 30 is provided on the insulating layer 300. The first pad structure 210 and the second pad structure 220 are electrically connected through the via 30.

[0039] Among them, the difference between the second pad structure 220 and the first pad structure 210 is that they are pad structures in different film layers. The second pad structure 220 can be arranged in the metal layer of the array substrate 10 that is not exposed on the surface. The first pad structure 210 and the second pad structure 220 are electrically connected. It can be understood that the lead-out pad unit 200 is essentially a three-dimensional pad. Since the lead-out pad unit 200 in this three-dimensional form has pad structures in more than one film layer, the first pad structure 210 exposed on the surface can be used to bind to an external connection structure or a driving unit, and the second pad structure 220 hidden in the circuit layer 12 can be electrically connected to the signal line 100 extending from the first area A1. Exemplarily, when some signal lines 100 are arranged in the metal layer where the second pad structure 220 is located, a direct connection can be achieved. When some signal lines 100 and the second pad structure 220 are arranged in different metal layers, the electrical connection between the two can be achieved through the via 30.

[0040] In addition, in this embodiment, the first pad structure 210 and the second pad structure 220 are electrically connected through the via 30, indicating that whether it is the first sub-pad structure 211 or the second sub-pad structure 212, it needs to be electrically connected to the second pad structure 220 hidden in the circuit layer 12 through the via 30. It can be understood that precisely because of the design that the first sub-pad structure 211 is electrically connected to the second pad structure 220 through the via 30, when the first sub-pad structure 211 peels off or falls off, the second pad structure 220 hidden in the circuit layer 12 cannot be connected to an external connection structure such as a side trace. In the embodiment of the present invention, by further fabricating the second sub-pad structure 212 and reconnecting the second sub-pad structure 212 to the second pad structure 220 hidden in the circuit layer 12 through the via 30, the second sub-pad structure 212 can replace the fallen-off first sub-pad structure 211 to meet the requirement of the connection between the signal line 100 in the display panel and the outside.

[0041] Continue to refer to Figures 3 - 5 , further, the projection area of the second pad structure 220 on the plane where the insulating layer 300 is located is the first projection area PA1, and a plurality of vias 30 are arranged in the insulating layer 300 in the first projection area PA1; the projection of the first sub-pad structure 211 on the plane where the insulating layer 300 is located covers all the vias 30 and is electrically connected to the corresponding second pad structure 220 through these vias 30; the projection of the second sub-pad structure 212 on the plane where the insulating layer 300 is located covers at least part of the vias 30 and is electrically connected to the corresponding second pad structure 220 through these vias 30.

[0042] As described above, the first sub-pad structure 211 and the second sub-pad structure 212 are essentially formed through two fabrication steps. The second sub-pad structure 212 is fabricated to compensate for the first sub-pad structure 211 that has fallen off at the same position. Generally, when fabricating the first sub-pad structure 211, the first sub-pad structure 211 needs to be connected to the second pad structure 220 through vias 30. Moreover, to ensure a good connection between the first sub-pad structure 211 and the second pad structure 220, the number of vias 30 is not limited to one, and multiple vias 30 will be evenly distributed in the projection area of the second pad structure 220. At this time, when fabricating the first sub-pad structure 211 using the thermal deposition process, each via 30 will be filled to achieve electrical connection between the upper and lower layer pad structures. For the position where the first sub-pad structure 211 has been peeled off, a second sub-pad structure 212 needs to be fabricated. However, there are differences in the fabrication process and precision between the second sub-pad structure 212 and the first sub-pad structure 211. Therefore, the second sub-pad structure 212 can be arranged to be electrically connected to the corresponding second pad structure 220 through some of the vias 30.

[0043] Figure 6 is a partial enlarged view of a display panel provided by an embodiment of the present invention. Refer to Figure 6 , in one embodiment, optionally, the second sub-pad structure 212 includes a plurality of first strip structures 2121 and a plurality of second strip structures 2122; the plurality of first strip structures 2121 all extend along the first direction X and are arranged along the second direction Y, and the plurality of second strip structures 2122 all extend along the second direction Y and are arranged along the first direction X; wherein, the first direction X intersects with the second direction Y; the plurality of second strip structures 2122 and the plurality of first strip structures 2121 overlap each other.

[0044] The second sub-pad structure 212 can be fabricated using a chemical vapor deposition process in combination with a laser scanning process. Specifically, taking tungsten metal as an example of the material, during the fabrication process, tungsten metal can be deposited to sequentially form a plurality of first strip structures 2121 row by row, where the first direction X is the row direction, and then a plurality of second strip structures 2122 can be formed column by column on the plurality of first strip structures 2121, where the second direction Y is the column direction. Thus, there can be a fixed spacing between adjacent first strip structures 2121, and there can also be a fixed spacing between adjacent second strip structures 2122. Therefore, the two strip structures can essentially overlap to form a mesh structure.

[0045] In this embodiment, the second sub-pad structure 212 is set as a mesh structure. On the one hand, this is due to the use of chemical vapor deposition process in combination with laser scanning process for preparation. On the other hand, through the concave and convex surface of the mesh structure, the bonding force with the surface of the array substrate 10 and the subsequent external driving unit or connection structure can be increased. For example, when preparing the side-walk wiring subsequently, it can ensure that the side-walk wiring is in close contact with the mesh-shaped second sub-pad structure 212. While avoiding the risk of peeling, it can also ensure good electrical conductivity. In addition, since there are voids in the mesh-shaped second sub-pad structure 212 that can expose the surface of the array substrate 10, when preparing the side-walk wiring subsequently, the area where the side-walk wiring exists will also be directly bonded and fixed to the array substrate 10, so that the second sub-pad can be clamped between the array substrate 10 and the side-walk wiring, which can also increase the reliability of the second sub-pad structure 212 fixed on the array substrate 10 to a certain extent and avoid the problem of peeling of the second sub-pad structure 212.

[0046] Figure 7 is a partial enlarged view of another display panel provided by an embodiment of the present invention. Refer to Figure 7 , in another embodiment, it is also optional that the second sub-pad structure 212 includes a plurality of first strip structures 2121; the plurality of first strip structures 2121 all extend along the first direction X and are arranged along the second direction Y; wherein, the first direction X intersects with the second direction Y.

[0047] Similarly, in this embodiment, the second sub-pad structure 212 can also be prepared by using chemical vapor deposition process in combination with laser scanning process. Taking the material being tungsten metal as an example, during the preparation process, tungsten metal can be deposited row by row or column by column to form a plurality of first strip structures 2121. At this time, the first direction X can be the row direction or the column direction. Similarly, in this embodiment, setting the second sub-pad structure 212 as a plurality of strip structures has the same or similar beneficial effects as setting it as a mesh structure, which will not be elaborated here.

[0048] Figure 8 is a partial enlarged view of yet another display panel provided by an embodiment of the present invention. Refer to Figure 8 , in yet another embodiment, it is also optional that the projection pattern of the second sub-pad structure 212 along the direction perpendicular to the array substrate 10 is the same as the projection pattern of the first sub-pad structure 211 along the direction perpendicular to the array substrate 10.

[0049] In this embodiment, there is no limitation on the preparation process of the second sub-pad structure 212. It can also be prepared by a chemical vapor deposition process in combination with a laser scanning process, or by other processes such as thermal deposition. The key lies in that when preparing the second sub-pad structure 212, it is necessary to ensure that the projection pattern is the same as that of the first sub-pad structure 211. For example, by using a chemical vapor deposition process in combination with a laser scanning process, strip-shaped structures without gaps are formed one by one to form an overall planar structure. At this time, since the second sub-pad structure 212 and the first sub-pad structure 211 have the same projection pattern and the same area, the adhesion force to the surface of the array substrate 10 is consistent. At the same time, it can also ensure that the electrical contact area with the structures such as side-walking lines for transmitting driving signals is the same, and there is no obvious difference in the conductivity between the two, avoiding the problem that the driving signals are different due to different preparation shapes of the two pad structures.

[0050] In the embodiment of the present invention, it is optional that the second sub-pad structure 212 is a conductive structure of a single material. At this time, the second sub-pad structure 212 can be prepared in a single process, avoiding adding too many processes. Specifically, the material can be tungsten, copper, silver, molybdenum, etc.

[0051] Figure 9 and Figure 10 is Figure 3 The other two cross-sectional schematic diagrams of the shown display panel at AA' and BB' are for reference Figure 9 and Figure 10 Furthermore, optionally, both the first sub-pad structure 211 and the second sub-pad structure 212 include at least one metal layer, and the number of metal layers in the second sub-pad structure 212 is less than the number of metal layers in the first sub-pad structure 211.

[0052] The first sub-pad structure 211 can be prepared from two metal layers, and the second sub-pad structure 212 can be prepared from one metal layer. Generally, multiple metal layers are provided in the circuit layer 12 of the array substrate 10. The two metal layers of the first sub-pad structure 211 can be the two upper metal layers in the circuit layer 12. During preparation, the insulating layer 300 in this area of the two metal layers can be removed so that the two metal layers are directly stacked.

[0053] The thickness of the single metal layer in the first sub-pad structure 211 can be within (including the endpoints), and the thickness of the second sub-pad structure 212 can be within (including the endpoints). When the thickness of the second sub-pad structure 212 is large enough, it can ensure that the via 30 in the insulating layer 300 between the first pad structure 210 and the second pad structure 220 is effectively filled during fabrication, thereby ensuring an effective connection between the second sub-pad structure 212 and the second pad structure 220 through the via 30. It should be noted that the thickness of the second sub-pad structure 212 here refers to the thickness of any region. For example, when the second sub-pad structure 212 is a mesh structure, the strip-shaped structures extending along the rows and columns will overlap, and the thickness of the overlapping region does not exceed

[0055] Figure 11 and Figure 12 are two schematic cross-sectional views of different positions of another display panel provided by an embodiment of the present invention. Refer to Figure 11 and Figure 12 , in a specific embodiment, optionally, the circuit layer 12 includes a first metal layer M1, a second metal layer M2, a third metal layer M3, and a fourth metal layer M4 arranged in sequence on the substrate 11; in the first region A1, insulating layers 300 are provided between the first metal layer M1 and the second metal layer M2, between the second metal layer M2 and the third metal layer M3, and between the third metal layer M3 and the fourth metal layer M4. In the second region A2, insulating layers 300 are provided between the first metal layer M1 and the second metal layer M2 and between the second metal layer M2 and the third metal layer M3. The insulating layer 300 between the second metal layer M2 and the third metal layer M3 in the first region A1 is the first insulating layer 301, and the insulating layer 300 between the second metal layer M2 and the third metal layer M3 in the second region A2 is the second insulating layer 302, and the thickness of the second insulating layer 302 is less than the thickness of the first insulating layer 301.

[0056] The signal line 100 is formed in the second metal layer M2, the first sub-pad structure 211 is formed in the third metal layer M3 and the fourth metal layer M4, and the first sub-pad structure 211 includes a first part 2111 and a second part 2112 connected to each other. The first part 2111 is located in the second region A2, and the second part 2112 is located in the first region A1; the circuit layer 12 further includes a fifth metal layer M5 in the second region A2, the fifth metal layer M5 is located on the side of the second insulating layer 302 away from the second metal layer M2, and the second sub-pad structure 212 is formed in the fifth metal layer M5.

[0057] Among them, the circuit layer 12 of the array substrate 10 is essentially composed of multiple metal layers. An insulating layer 300 is provided between each metal layer for isolation. Corresponding metal traces are formed in each metal layer, and the metal traces between each layer are electrically connected through vias 300 to form a pixel circuit for controlling the light emission of the light-emitting element. In addition, signal lines 100 for driving the pixel circuit to work are provided in specific metal layers. The signal lines 100 receive external driving signals through lead pads and supply them to the pixel circuit, thereby driving the pixel circuit to control the light-emitting element to emit light. In this embodiment, the circuit layer 12 includes a total of five metal layers. The first metal layer M1 to the fourth metal layer M4 are used to prepare the pixel circuit, the signal lines 100, and the lead pad unit 200. In other words, when preparing the circuit layer 12 in the array substrate 10, the manufacturing process of the metal layer is adopted to simultaneously prepare the signal lines 100 and the lead pad unit 200. Specifically, the signal lines 100 can be simultaneously formed in the second metal layer M2, and the first sub-lead pad structure 211 can be simultaneously formed in the third metal layer M3 and the fourth metal layer M4. As described above, the first sub-lead pad structure 211 is prone to peeling or falling off. After detecting and determining peeling or falling off, the fifth metal layer M5 can be continuously prepared at the same position in the second area A2 to form the second sub-lead pad structure 212.

[0058] In addition, it should be added that in this embodiment, the formation of the height difference is mainly controlled by the insulating layer 300 on the second metal layer M2. As Figure 11 and Figure 12 shown, in the first area A1 and the second area A2, insulating layers 300 with different thicknesses are provided between the second metal layer M2 and the third metal layer M3. That is, the thickness of the first insulating layer 301 in the first area A1 is significantly greater than the thickness of the second insulating layer 302 in the second area A2, thereby saving the longitudinal space in the second area A2. In addition, in the second area A2, no insulating layer is provided between the third metal layer M3 and the fourth metal layer M4, which can further save the longitudinal space in the second area A2.

[0059] For the insulating layer between the second metal layer M2 and the third metal layer M3 with different thicknesses in the first area A1 and the second area A2, the embodiment of the present invention provides a specific implementation solution. Continuing to refer to Figure 11 and Figure 12 , optionally, the first insulating layer 301 includes a first sub-insulating layer 3011 and a second sub-insulating layer 3012. The first sub-insulating layer 3011 is made of an organic material, and the second sub-insulating layer 3012 is made of an inorganic material. The second sub-insulating layer 3012 is located on the side of the first sub-insulating layer 3011 away from the second metal layer M2; the second insulating layer 302 includes a third sub-insulating layer 3023. The third sub-insulating layer 3023 is connected to the first sub-insulating layer 3011 and is made of the same organic material.

[0060] Among them, the first sub-insulating layer 3011 and the third sub-insulating layer 3023 are substantially organic insulating layers, and the second sub-insulating layer 3012 is substantially an inorganic insulating layer. In essence, this embodiment is to prepare an inorganic layer and an organic layer on the second metal layer M2, and then prepare the third metal layer M3. When preparing the inorganic layer, through the design of the mask opening, it can be controlled that the inorganic layer is only formed in the first region A1, so that only one organic insulating layer exists between the second metal layer M2 and the third metal layer M3 in the second region A2, thereby thinning the insulating layer between the second metal layer M2 and the third metal layer M3 in the second region A2, that is, the second insulating layer 302, providing the possibility for a height difference to be formed between the exposed surfaces of the second region A2 and the first region A1.

[0061] Based on the height difference existing between the exposed surfaces of the first region A1 and the second region A2, when setting the first sub-pad structure 211, in order to increase the attachment area with the surface of the array substrate, the first sub-pad structure 211 can be set to extend to the first region A1, that is, in addition to the first part 2111 located in the second region A2, the first sub-pad structure 211 further includes a second part 2112 extending to the first region A1.

[0062] Figure 13 It is a schematic cross-sectional view of another display panel provided by an embodiment of the present invention. Refer to Figure 13 Optionally, the second sub-pad structure 212 includes a third part 2121 and a fourth part 2122 that are connected to each other. The third part 2121 is located in the second region A2, and the fourth part 2122 is located in the first region A1.

[0063] Similarly, when setting the second sub-pad structure 212, it can also be optionally extended into the first region A1, that is, in addition to the third part 2121 located in the second region A2, it further includes a fourth part 2122 extending to the first region A1. Thus, the second sub-pad structure 212 can have a larger attachment area with the surface of the array substrate 10, increasing the adhesion force with the surface of the array substrate 10 and avoiding the occurrence of peeling or falling off.

[0064] Continue to refer to Figures 11 - 13 More specifically, the lead pad unit 200 further includes a second pad structure 220 and a third pad structure 230; the second pad structure 220 is formed in the second metal layer M2, the first pad structure 210 is electrically connected to the second pad structure 220 through a via 30 provided on the second insulating layer 302, and the second pad structure 220 is electrically connected to the signal line 100; the third pad structure 230 is formed in the first metal layer M1, the insulating layer between the first metal layer M1 and the second metal layer M2 is the third insulating layer 303, and the second pad structure 220 is electrically connected to the third pad structure 230 through a via 30 provided on the third insulating layer 303.

[0065] In this embodiment, the lead-out pad unit 200 is also a three-dimensional structure. It not only has a first pad structure 210 on the surface of the array substrate 10, but also has a second pad structure 220 in the second metal layer M2 formed inside the circuit layer 12 and a third pad structure 230 in the first metal layer M1. The three layers of pad structures are connected through vias 30 in the insulating layer 300 therebetween, thus forming a three-dimensional lead-out pad unit 200. This three-dimensional lead-out pad unit 200 can be applied to signal lines 100 located in different metal layers. Exemplarily, when the signal line 100 is located in the second metal layer M2, the signal line 100 can be connected to the second pad structure 220 in the same second metal layer M2 during fabrication, that is, the connection between the signal line 100 and the corresponding lead-out pad unit 200 is achieved; when the signal line 100 is located in the first metal layer M1, the signal line 100 can be connected to the third pad structure 230 in the same first metal layer M1 during fabrication, that is, the connection between the signal line 100 and the corresponding lead-out pad is achieved.

[0066] Figure 14 is a schematic cross-sectional view of another display panel provided by an embodiment of the present invention. Refer to Figure 14 , the display panel further includes a plurality of side traces 400. The side traces 400 extend from the second region A2 of the array substrate 10 where the first end is located, along the side surface of the array substrate 10 to the back surface of the array substrate 10 where the second end is located; the plurality of side traces 400 include at least one first side trace 401 and a second side trace 402 other than the first side trace 401; the first end of the first side trace 401 covers at least a part of the corresponding first sub-pad structure 211, and the first end of the second side trace 402 covers at least a part of the corresponding second sub-pad structure 212.

[0067] The display panel in this embodiment is essentially a borderless display panel for splicing. Side traces 400 need to be further fabricated on the lead-out pad unit 200 to further lead out to the back surface of the panel through the side traces 400, and then an external driving unit is bonded to the back surface of the panel. The two side traces 400 here, namely the first side trace 401 and the second side trace 402, are essentially the same. They can be fabricated using the same material in the same process. The only difference is that the first pad structure 210 on the surface in the lead-out pad unit 200 to which they are connected is the first sub-pad structure 211 and the second sub-pad structure 212, or rather, the material of the first pad structure 210 to which they are connected is different. For the material, process, shape, etc. of the side traces 400, those skilled in the art can design and fabricate according to actual needs, and no further limitations are made here.

[0068] Based on the same inventive concept, embodiments of the present invention also provide corresponding display devices. Figure 15 And Figure 16 are schematic structural diagrams of two display devices provided by embodiments of the present invention. Referring to Figure 15 and Figure 16 , the display device 2 may include the display panel 1 provided by any embodiment of the present invention. In one embodiment, as shown in Figure 15 , the display device 2 may include one display panel 1. In another embodiment, as shown in Figure 16 , the display device 2 may be a splicing screen formed by splicing at least two display panels 1, for example, a splicing screen formed by splicing a total of four display panels 1 in a 2*2 manner. The structure of the display panel 1 has been described in the above embodiments and will not be elaborated here. The splicing screen formed by splicing at least two display panels 1 provided by embodiments of the present invention can be used for large-screen display, for example, applied to occasions such as conference rooms, exhibition halls, billboards, and video walls.

[0069] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments, combinations with each other, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the inventive concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A display panel, characterized in that, An array substrate is included, and the array substrate includes a first region and a second region connected to the first region; the array substrate further includes a substrate and a circuit layer located on one surface of the substrate; there is a height difference between the surface of the circuit layer facing away from the substrate in the first region and the surface of the circuit layer facing away from the substrate in the second region in a direction perpendicular to the array substrate. The first region includes a plurality of signal lines, and the signal lines extend to the second region. The second region includes a plurality of lead pad units, and each lead pad unit includes a first pad structure, and the first pad structure is located on the surface of the circuit layer facing away from the substrate in the second region; the first pad structure is electrically connected to the signal line. The plurality of first pad structures include a first sub-pad structure and a second sub-pad structure; the materials of the first sub-pad structure and the second sub-pad structure are different.

2. The display panel according to claim 1, wherein Each lead pad unit further includes a second pad structure, the first pad structure and the second pad structure are located in different film layers and an insulating layer is provided therebetween, vias are provided on the insulating layer, and the first pad structure and the second pad structure are electrically connected through the vias.

3. The display panel according to claim 2, wherein The projection area of the second pad structure in the plane of the insulating layer is a first projection area, and a plurality of the vias are provided in the first projection area of the insulating layer. The projection of the first sub-pad structure in the plane of the insulating layer covers all the vias, and is electrically connected to the corresponding second pad structure through these vias. The projection of the second sub-pad structure in the plane of the insulating layer covers at least part of the vias, and is electrically connected to the corresponding second pad structure through these vias.

4. The display panel according to claim 1, wherein The second sub-pad structure includes a plurality of first strip structures and a plurality of second strip structures. The plurality of first strip structures all extend along a first direction and are arranged along a second direction, and the plurality of second strip structures all extend along the second direction and are arranged along the first direction; wherein, the first direction intersects with the second direction. The plurality of second strip structures overlap with the plurality of first strip structures.

5. The display panel according to claim 1, wherein The second sub-pad structure includes a plurality of first strip structures. The plurality of first strip structures all extend along a first direction and are arranged along a second direction; wherein, the first direction intersects with the second direction.

6. The display panel according to claim 1, wherein The projection pattern of the second sub-pad structure in a direction perpendicular to the array substrate is the same as the projection pattern of the first sub-pad structure in a direction perpendicular to the array substrate.

7. The display panel according to claim 1, characterized in that, The second sub-pad structure is a conductive structure of a single material.

8. The display panel according to claim 1, wherein Both the first sub-pad structure and the second sub-pad structure include at least one metal layer, and the number of metal layers in the second sub-pad structure is less than the number of metal layers in the first sub-pad structure.

9. The display panel according to claim 1, wherein The thickness of the second sub-pad structure is D, where 10. The display panel according to claim 1, wherein The circuit layer includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer arranged in sequence on the substrate. In the first region, insulating layers are provided between the first metal layer and the second metal layer, between the second metal layer and the third metal layer, and between the third metal layer and the fourth metal layer; in the second region, insulating layers are provided between the first metal layer and the second metal layer and between the second metal layer and the third metal layer. The insulating layer between the second metal layer and the third metal layer in the first region is the first insulating layer, and the insulating layer between the second metal layer and the third metal layer in the second region is the second insulating layer, and the thickness of the second insulating layer is less than the thickness of the first insulating layer. The signal line is formed in the second metal layer, the first sub-pad structure is formed in the third metal layer and the fourth metal layer, and the first sub-pad structure includes a first part and a second part connected to each other, the first part is located in the second region, and the second part is located in the first region. The circuit layer further includes a fifth metal layer in the second region, the fifth metal layer is located on a side of the second insulating layer away from the second metal layer, and the second sub-pad structure is formed in the fifth metal layer.

11. The display panel according to claim 10, wherein The second sub-pad structure includes a third part and a fourth part connected to each other, the third part is located in the second region, and the fourth part is located in the first region.

12. The display panel according to claim 10, wherein The lead-out pad unit further includes a second pad structure and a third pad structure. The second pad structure is formed in the second metal layer, the first pad structure is electrically connected to the second pad structure through a via formed in the second insulating layer, and the second pad structure is electrically connected to the signal line. The third pad structure is formed in the first metal layer, the insulating layer between the first metal layer and the second metal layer is the third insulating layer, and the second pad structure is electrically connected to the third pad structure through a via formed in the third insulating layer.

13. The display panel according to claim 10, wherein The first insulating layer includes a first sub-insulating layer and a second sub-insulating layer, the first sub-insulating layer is made of an organic material, the second sub-insulating layer is made of an inorganic material, and the second sub-insulating layer is located on a side of the first sub-insulating layer away from the second metal layer. The second insulating layer includes a third sub-insulating layer, and the third sub-insulating layer is connected to the first sub-insulating layer and made of the same organic material.

14. The display panel according to claim 1, wherein It further includes a plurality of side walkways, and the side walkways extend from the second region of the array substrate where the first end is located, along the side of the array substrate to the back of the array substrate where the second end is located. The plurality of side walkways include at least one first side walkway and a second side walkway other than the first side walkway. The first end of the first side walkway covers at least a part of the corresponding first sub-pad structure, and the first end of the second side walkway covers at least a part of the corresponding second sub-pad structure.

15. A display device, characterized in that, It includes a display panel according to any one of claims 1-14.

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