Flexible circuit board, display module, and electronic device

Abstract

A flexible circuit board (100), a display module (1000), and an electronic device. The flexible circuit board (100) comprises first binding terminals (30) provided on a first surface (11) of a substrate layer (10) and pressure transmission portions (50) provided on a second surface (12) of the substrate layer (10). Each pressure transmission portion (50) at least comprises a part corresponding to at least part of a first binding terminal (30), so that the pressure transmission portion (50) can transmit pressure to the first binding terminal (30) through the base material layer (10), to mitigate the problem of inclination due to lateral pressure during binding of the flexible circuit board (100) and a printed circuit board (200).

Description

Flexible circuit board, display module and electronic device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a flexible circuit board, a display module, and an electronic device. Background Art

[0002] Currently, most medium- and large-sized display devices (such as foldable laptops and tablets) use flexible printed circuits (FPCs) to input signals from printed circuit board assemblies (PCBAs) to the display panel, enabling in-plane signal processing and power supply. The FPC and PCB are bonded together using high-temperature hot-pressing. Due to the large number of pins in the bonding area, both the FPC and PCB utilize a double-row design. The FPC comprises a bottom copper layer and a top copper layer. The bottom copper layer forms the first traces and the double-row first bonding terminals, while the top copper layer forms the second traces. The first row of the double-row first bonding terminals is directly electrically connected to a portion of the first traces, while the second row of the double-row first bonding terminals is electrically connected to another portion of the first traces via a bridged second trace. However, the misalignment of the second traces with the double-row first bonding terminals can cause lateral pressure tilting during bonding between the FPC and PCB, leading to abnormal bonding impedance in the bonding area and reliability testing. SUMMARY OF THE INVENTION

[0003] The present application provides a flexible circuit board, a display module, and an electronic device to alleviate the technical problem of lateral pressure tilting generated when the existing flexible circuit board and the printed circuit board are bound.

[0004] To solve the above problems, the technical solutions provided by this application are as follows:

[0005] The embodiment of the present application provides a flexible circuit board, which includes:

[0006] The substrate layer includes a first surface and a second surface opposite to each other, wherein the first surface includes a wiring area and a first binding area located on one side of the wiring area;

[0007] a plurality of first traces disposed on the first surface and located in the trace area, the plurality of first traces extending along a first direction and spaced apart along a second direction, and the plurality of first traces including first-type traces and second-type traces electrically isolated from each other;

[0008] a plurality of first binding terminals, disposed on the first surface and located in the first binding area, the plurality of first binding terminals extending along the first direction and spaced apart along the second direction, the plurality of first binding terminals including first-type binding terminals and second-type binding terminals electrically isolated from each other, the second-type binding terminals being located on a side of the first-type binding terminals away from the first traces, each first-type binding terminal being electrically connected to at least one first-type trace, and each second-type binding terminal being electrically connected to at least one second-type trace;

[0009] a plurality of second traces, disposed on the second surface and corresponding to the gaps between the first-type binding terminals, each second trace being electrically connected between the second-type trace and the second-type binding terminal; and

[0010] A plurality of pressure transmission parts are provided on the second surface, each of the pressure transmission parts at least including a portion corresponding to at least a portion of the first binding terminal, so that the pressure transmission part can transmit pressure to the first binding terminal through the substrate layer.

[0011] In the flexible circuit board provided in the embodiment of the present application, the elastic modulus of the pressure transmission portion is greater than or equal to the elastic modulus of the second trace.

[0012] In the flexible circuit board provided in the embodiment of the present application, the material of the pressure transmission portion is the same as the material of the second trace.

[0013] In the flexible circuit board provided in the embodiment of the present application, in a direction perpendicular to the substrate layer, the thickness of the pressure transmission portion is greater than or equal to the thickness of the second trace.

[0014] In the flexible circuit board provided in the embodiment of the present application, there is a first gap between two adjacent first-type binding terminals, the width of the second trace in the second direction is smaller than the distance of the first gap, and the orthographic projection of the second trace on the substrate layer is within the range of the orthographic projection of the first gap on the substrate layer.

[0015] In the flexible circuit board provided in the embodiment of the present application, the flexible circuit board further includes a covering layer, and the covering layer covers the second trace, the pressure transmission part, and the base material layer.

[0016] In the flexible circuit board provided in the embodiment of the present application, the thickness of the covering layer covering the second trace is smaller than the thickness of the covering layer covering the base material layer.

[0017] In the flexible circuit board provided in the embodiment of the present application, the pressure transmission portion includes a first pressure transmission sub-portion, the first pressure transmission sub-portion is located between two adjacent second traces, and is arranged corresponding to the first type binding terminal.

[0018] In the flexible circuit board provided in the embodiment of the present application, there is a second gap between two adjacent second traces, the first pressure transmission sub-section is located in the second gap, and the width of the first pressure transmission sub-section in the second direction is smaller than the distance of the second gap.

[0019] In the flexible circuit board provided in the embodiment of the present application, the central axis of the first pressure transmission sub-portion in the first direction coincides with the central axis of the first type binding terminal in the first direction.

[0020] In the flexible circuit board provided in the embodiment of the present application, the first type of binding terminals and the second type of binding terminals are arranged opposite to each other, the second wiring is also arranged corresponding to the gap of the second type of binding terminals, and the pressure transmission part also includes a second pressure transmission sub-part, and the second pressure transmission sub-part is arranged corresponding to the second type of binding terminals.

[0021] In the flexible printed circuit board provided in the embodiment of the present application, the second trace is electrically connected to an end of the second-type binding terminal away from the first-type binding terminal.

[0022] In the flexible circuit board provided in an embodiment of the present application, there is a third gap between the two adjacent second-type binding terminals, the width of the second trace in the second direction is smaller than the distance of the third gap, and the orthographic projection of the second trace on the substrate layer is within the range of the orthographic projection of the third gap on the substrate layer.

[0023] In the flexible circuit board provided in the embodiment of the present application, there is also a fourth gap between the two adjacent second traces, the second pressure transmission sub-section is located in the fourth gap, and the width of the second pressure transmission sub-section in the second direction is less than the distance of the fourth gap.

[0024] In the flexible circuit board provided in the embodiment of the present application, the central axis of the second pressure transmission sub-portion in the first direction coincides with the central axis of the second-type binding terminal in the first direction.

[0025] In the flexible circuit board provided in the embodiment of the present application, the first type of binding terminals and the second type of binding terminals are arranged alternately, and the second trace is electrically connected to one end of the second type of binding terminals close to the first type of binding terminals; the pressure transmission part also includes a third pressure transmission sub-part, and the third pressure transmission sub-part is arranged corresponding to the second type of binding terminals.

[0026] In the flexible circuit board provided in the embodiment of the present application, the central axis of the third pressure transmission sub-portion in the first direction coincides with the central axis of the second-type binding terminal in the first direction.

[0027] In the flexible circuit board provided in the embodiment of the present application, the first type of binding terminals and the second type of binding terminals are arranged alternately, the second wiring is electrically connected to the end of the second type of binding terminals away from the first type of binding terminals, and the central axis of the second wiring in the first direction coincides with the central axis of the second type of binding terminals in the first direction.

[0028] An embodiment of the present application also provides a display module, which includes a display panel, a printed circuit board, and a flexible circuit board electrically connected between the display panel and the printed circuit board, wherein the flexible circuit board includes the flexible circuit board of one of the aforementioned embodiments; wherein the printed circuit board includes a second binding area opposite to the first binding area of ​​the flexible circuit board, and the printed circuit board is provided with a plurality of second binding terminals in the second binding area, and the second binding terminals are bound to the corresponding first binding terminals on the flexible circuit board.

[0029] In the display module provided in the embodiment of the present application, the orthographic projection of the first binding terminal on the printed circuit board is located within the orthographic projection range of the corresponding second binding terminal on the printed circuit board.

[0030] In the display module provided by the embodiment of the present application, the orthographic projection of the pressure transmission portion corresponding to the first binding terminal on the printed circuit board is located within the orthographic projection range of the corresponding second binding terminal on the printed circuit board.

[0031] In the display module provided in the embodiment of the present application, the central axis of the first binding terminal coincides with the central axis of the corresponding second binding terminal.

[0032] In the display module provided in the embodiment of the present application, the second binding terminal includes a third type of binding terminal and a fourth type of binding terminal that are electrically isolated from each other, the third type of binding terminal is bound to the first type of binding terminal on the flexible circuit board, and the fourth type of binding terminal is bound to the second type of binding terminal on the flexible circuit board.

[0033] An embodiment of the present application further provides an electronic device, which includes the display module of one of the aforementioned embodiments. Beneficial effects

[0034] In the flexible circuit board, display module and electronic device provided by the present application, the flexible circuit board includes a substrate layer, a plurality of first traces and a plurality of first binding terminals arranged on the first surface of the substrate layer, and a plurality of second traces and a plurality of pressure transmission parts arranged on the second surface of the substrate layer, the first surface includes a trace area and a first binding area located on one side of the trace area, a plurality of first traces are located in the trace area, a plurality of first traces extend along the first direction and are spaced apart along the second direction, and a plurality of first traces include first and second types of traces that are electrically isolated from each other, a plurality of first binding terminals are located in the first binding area, a plurality of first binding terminals extend along the first direction and are spaced apart along the second direction, and a plurality of first binding terminals include first and second types of binding terminals that are electrically isolated from each other, and the second types of binding The terminal is located on the side of the first type binding terminal away from the first wiring, each first type binding terminal is electrically connected to at least one first type wiring, each second type binding terminal is electrically connected to at least one second type wiring, multiple second wirings are arranged corresponding to the gaps of the first type binding terminals, each second wiring is electrically connected between the second type wiring and the second type binding terminal, and each pressure transmission part includes at least a part corresponding to at least part of the first binding terminal, so that the pressure transmission part can transmit pressure to the first binding terminal through the substrate layer. In this way, when the flexible circuit board is bound to the printed circuit board, the pressure transmission part can apply positive pressure to the binding terminal through the substrate layer, avoiding lateral pressure tilt of the binding terminal, and alleviating the technical problem of lateral pressure tilt when the existing flexible circuit board and printed circuit board are bound. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] FIG1 is a schematic diagram of binding a flexible circuit board and a printed circuit board in the prior art.

[0037] FIG2 is a schematic diagram of a cross-sectional structure of a flexible circuit board provided in an embodiment of the present application.

[0038] FIG. 3 is a detailed schematic diagram of the first surface of the substrate layer in FIG. 2 .

[0039] FIG. 4 is a detailed schematic diagram of the second surface of the substrate layer in FIG. 2 .

[0040] FIG. 5 is a detailed schematic diagram of the second wiring and the pressure transmission portion in FIG. 4 .

[0041] FIG6 is a schematic diagram of the cross-sectional structure along the MM' direction in FIG5.

[0042] FIG. 7 is a schematic diagram of the cross-sectional structure along the NN′ direction in FIG. 5 .

[0043] FIG8 is a schematic diagram of the flexible circuit board and the printed circuit board after being bound together in FIG2 .

[0044] FIG9 is a schematic diagram of a top view of the pressure transmission portion provided in an embodiment of the present application.

[0045] FIG10 is a schematic diagram of the cross-sectional structure along line QQ′ in FIG9 .

[0046] FIG11 is another schematic top view of the structure of the pressure transmission portion provided in an embodiment of the present application.

[0047] FIG12 is a schematic diagram of the cross-sectional structure along line RR′ in FIG11 .

[0048] FIG13 is a schematic diagram of an arrangement of first-type binding terminals and second-type binding terminals provided in an embodiment of the present application.

[0049] FIG14 is a schematic diagram showing the connection between the second type binding terminal and the second trace in FIG13 .

[0050] FIG15 is another schematic diagram of the connection between the second type of binding terminal and the second trace provided in an embodiment of the present application.

[0051] FIG16 is another schematic diagram of the connection between the second type of binding terminal and the second trace provided in an embodiment of the present application.

[0052] FIG17 is a schematic diagram of a top view of the structure of a display module provided in an embodiment of the present application.

[0053] FIG18 is a schematic diagram showing the arrangement of the second binding terminals on the printed circuit board in FIG17 . Modes for Carrying Out the Invention

[0054] The following descriptions of the embodiments are with reference to the attached diagrams to illustrate specific embodiments that the present application can be implemented in. The directional terms mentioned in this application, such as [up], [down], [front], [back], [left], [right], [inside], [outside], [side], etc., are only with reference to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the present application, rather than to limit the present application. In the figures, units with similar structures are represented by the same reference numerals. In the accompanying drawings, the thickness of some layers and areas is exaggerated for clarity of understanding and ease of description. That is, the size and thickness of each component shown in the drawings are arbitrarily shown, but the present application is not limited to this.

[0055] In response to the problem of lateral pressure tilting when the flexible circuit board and the printed circuit board are bound in the prior art, the inventors of this application found in their research that it was mainly caused by the misalignment of the second trace and the double-row first binding terminal. Referring to Figure 1, Figure 1 is a schematic diagram of the binding of a flexible circuit board and a printed circuit board in the prior art. In Figure 1, the printed circuit board 500 and the flexible circuit board 600 are bound together by applying pressure through a pressure mechanism 700. A first binding terminal 601 is provided on the flexible circuit board 600, and a second binding terminal 501 is provided on the printed circuit board 500. The second trace 602 on the flexible circuit board 600 is set corresponding to the gap between the adjacent first binding terminals 601, so that the second trace 602 is misaligned with the corresponding first binding terminal 601. In this way, during the binding process of the printed circuit board 500 and the flexible circuit board 600, since the first binding terminal 601 and the second trace 602 on the flexible circuit board 600 are staggered, when pressure is applied to the flexible circuit board 600 under high temperature conditions, the first binding terminal 601 will be tilted relative to the second binding terminal 501, thereby causing a gap 502 to exist between the first binding terminal 601 and the second binding terminal 501, resulting in poor contact between the first binding terminal 601 on the flexible circuit board 600 and the second binding terminal 501 on the printed circuit board 500, thereby causing abnormal pressing impedance in the binding area and abnormal reliability test.

[0056] To this end, the present application provides a flexible circuit board, a display module, and an electronic device to solve the above problems.

[0057] Please refer to Figures 2 to 8. Figure 2 is a schematic cross-sectional view of a flexible circuit board according to an embodiment of the present application. Figure 3 is a detailed schematic view of the first surface of the substrate layer in Figure 2. Figure 4 is a detailed schematic view of the second surface of the substrate layer in Figure 2. Figure 5 is a detailed schematic view of the second trace and pressure transmission portion in Figure 4. Figure 6 is a schematic cross-sectional view taken along the M-M' direction in Figure 5. Figure 7 is a schematic cross-sectional view taken along the N-N' direction in Figure 5. Figure 8 is a schematic view of the flexible circuit board in Figure 2 after being bonded to a printed circuit board. Referring to Figures 2 and 3, a flexible circuit board 100 includes a substrate layer 10, which includes opposing first and second surfaces 11 and 12. The flexible circuit board 100 also includes a plurality of first traces 20 and a plurality of first binding terminals 30 disposed on the first surface 11, and a plurality of second traces 40 and a plurality of pressure transmission portions 50 disposed on the second surface 12.

[0058] The flexible circuit board 100 further includes a covering layer 60 covering the second trace 40 , the pressure transmission portion 50 , and the substrate layer 10 . The covering layer 60 may be made of the same material as the substrate layer 10 , such as a flexible film such as polyimide (PI).

[0059] Specifically, referring to Figure 3, the first surface 11 includes a routing area 111 and a first binding area 112 located on one side of the routing area 111. A plurality of first routing lines 20 are provided on the first surface 11 and located in the routing area 111. The plurality of first routing lines 20 extend along a first direction X and are spaced apart along a second direction Y. The plurality of first routing lines 20 include first-type routing lines 21 and second-type routing lines 22 that are electrically isolated from each other. The first-type routing lines 21 and the second-type routing lines 22 are alternately arranged to rationally utilize the space in the routing area 111. The first direction X and the second direction Y are different. For example, the first direction X is a column direction, the second direction Y is a row direction, and the first direction X is perpendicular to the second direction Y.

[0060] A plurality of first binding terminals 30 are arranged on the first surface 11 and located in the first binding area 112. The plurality of first binding terminals 30 extend along the first direction X and are arranged at intervals along the second direction Y. The plurality of first binding terminals 30 include first-type binding terminals 31 and second-type binding terminals 32 that are electrically isolated from each other. The second-type binding terminals 32 are located on the side of the first-type binding terminals 31 away from the first trace 20. Each of the first-type binding terminals 31 is electrically connected to at least one of the first-type traces 21, and each of the second-type binding terminals 32 is electrically connected to at least one of the second-type traces 22.

[0061] Optionally, the first traces 20 and the first binding terminals 30 are made of the same material, such as copper. In this case, the first traces 20 and the first binding terminals 30 are formed under the same process conditions, and the first type of traces 21 and the first type of binding terminals 31 can be integrally formed.

[0062] Referring to Figure 4 , multiple second traces 40 are disposed on the second surface 12 and arranged corresponding to the gaps between the first-type binding terminals 31. Each second trace 40 is electrically connected between the second-type trace 22 and the second-type binding terminal 32, such that the second-type binding terminal 32 is electrically connected to the second-type trace 22 through the bridge of the second trace 40. Specifically, the end of the second trace 40 closest to the first trace 20 is electrically connected to the second-type trace 22 via a first via 401, and the end of the second trace 40 farther from the first trace 20 is electrically connected to the second-type binding terminal 32 via a second via 402. Both the first via 401 and the second via 402 are formed by punching holes in the substrate layer 10.

[0063] The pressure transmission part 50 is arranged on the second surface 12, and each pressure transmission part 50 includes at least a part corresponding to at least part of the first binding terminal 30, so that the pressure transmission part 50 can transmit pressure to the first binding terminal 30 through the substrate layer 10. In this way, when the flexible circuit board 100 is bound to the printed circuit board, the pressure transmission part 50 can apply positive pressure to the binding terminal through the substrate layer 10, avoiding lateral pressure tilt of the binding terminal, and alleviating the technical problem of lateral pressure tilt generated when the existing flexible circuit board and the printed circuit board are bound.

[0064] The elastic modulus of the pressure transmission part 50 is greater than or equal to the elastic modulus of the second wiring 40, so that the hardness of the pressure transmission part 50 is at least not less than the hardness of the second wiring 40. Furthermore, when the pressure transmission part 50 and the second wiring 40 are subjected to the same pressure, the deformation of the pressure transmission part 50 is less than or equal to the deformation of the second wiring 40, so as to ensure that the binding pressure can directly act on the first binding terminal 30 located below the pressure transmission part 50, thereby preventing the first binding terminal 30 from being tilted due to lateral pressure. Optionally, the material of the pressure transmission part 50 is the same as that of the second wiring 40, such as copper, to reduce the difficulty of the process. The pressure transmission part 50 is in a floating state, that is, the pressure transmission part 50 is not connected to the electrical signal.

[0065] Furthermore, in a direction perpendicular to the substrate layer 10, the thickness of the pressure transmission portion 50 is greater than or equal to the thickness of the second trace 40. When the thickness of the pressure transmission portion 50 is equal to the thickness of the second trace 40, the pressure transmission portion 50 and the second trace 40 can withstand the same pressure, and the pressure applied to the pressure transmission portion 50 can pass through the substrate layer 10 and act on the first binding terminal 30 located below the pressure transmission portion 50, thereby preventing the first binding terminal 30 from tilting due to lateral pressure. When the thickness of the pressure transmission part 50 is greater than the thickness of the second wiring 40, the pressure transmission part 50 can withstand more pressure than the second wiring 40, so that most of the binding pressure is applied to the pressure transmission part 50. In this way, the pressure on the pressure transmission part 50 can act on the first binding terminal 30 located below the pressure transmission part 50 through the substrate layer 10, avoiding the first binding terminal 30 from being tilted by lateral pressure. At the same time, it can also protect the second wiring 40, avoiding the binding pressure from acting on the second wiring 40 and causing defects such as cracks in the second wiring 40.

[0066] The relative positional relationship among the first binding terminal 30 , the second wiring 40 , and the pressure transmission portion 50 will be described in detail below.

[0067] 4 and 5 , a first gap 311 is defined between two adjacent first-type binding terminals 31. The width D1 of the second trace 40 in the second direction Y is less than the distance L1 of the first gap 311. The orthographic projection of the second trace 40 on the substrate layer 10 lies within the orthographic projection of the first gap 311 on the substrate layer 10. In other words, the orthographic projection of the second trace 40 on the substrate layer 10 does not overlap with the orthographic projection of the first-type binding terminal 31 on the substrate layer 10, thereby preventing coupling capacitance between the second trace 40 and the first-type binding terminal 31, thereby preventing interference with signal transmission by the first-type trace 21.

[0068] Optionally, the width D2 of the first-type binding terminal 31 in the second direction Y ranges from 125 microns to 225 microns, such as 125 microns, 135 microns, 150 microns, 175 microns, 190 microns, 210 microns, 225 microns, etc. The distance L1 of the first gap 311 ranges from 125 microns to 225 microns, such as 125 microns, 135 microns, 150 microns, 175 microns, 190 microns, 210 microns, 225 microns, etc. The width D2 of the first-type binding terminal 31 in the second direction Y can be equal to the distance L1 of the first gap 311, such as 175 microns. However, the present application is not limited to this, and the width D2 of the first-type binding terminal 31 in the present application can also be greater than the distance L1 of the first gap 311.

[0069] Optionally, the pressure transmission part 50 includes a first pressure transmission sub-part 51 and a second pressure transmission sub-part 52, and the first pressure transmission sub-part 51 and the second pressure transmission sub-part 52 are both located between two adjacent second lines 40, and the first pressure transmission sub-part 51 is set corresponding to the first type binding terminal 31, and the second pressure transmission sub-part 52 is set corresponding to the second type binding terminal 32.

[0070] A second gap 403 is defined between two adjacent second traces 40. The first pressure transmission sub-section 51 is located within the second gap 403, and the width D3 of the first pressure transmission sub-section 51 in the second direction Y is less than the distance L2 of the second gap 403, thereby preventing short circuits between adjacent second traces 40. Furthermore, the first-type binding terminals 31 are positioned corresponding to the second gap 403, and the width D2 of the first-type binding terminals 31 in the second direction Y is less than the distance L2 of the second gap 403. The orthographic projections of the first-type binding terminals 31 on the substrate layer 10 fall within the range of the orthographic projection of the substrate layer 10, thereby preventing overlap between the first-type binding terminals 31 and the second traces 40.

[0071] Optionally, the width D3 of the first pressure transmission sub-section 51 in the second direction Y is also smaller than the width D2 of the first type binding terminal 31 in the second direction Y. In the second direction Y, the orthographic projection of the first pressure transmission sub-section 51 on the substrate layer 10 falls within the range of the orthographic projection of the first type binding terminal 31 on the substrate layer 10. Furthermore, the central axis P1 of the first pressure transmission sub-section 51 in the first direction X coincides with the central axis of the first type binding terminal 31 in the first direction X, so that the binding pressure applied to the first pressure transmission sub-section 51 can act on the middle area of ​​the first type binding terminal 31 through the substrate layer 10, avoiding uneven force on the first type binding terminal 31 and causing lateral pressure tilt. It should be noted that since the central axis P1 of the first pressure transmission sub-section 51 in the first direction X coincides with the central axis of the first type binding terminal 31 in the first direction X, the central axis of the first type binding terminal 31 in the first direction X is not shown in Figure 5.

[0072] 3 and 5 , the first type binding terminal 31 and the second type binding terminal 32 are arranged opposite to each other, and the vertical orthographic projection of the second type binding terminal 32 in the first direction X overlaps with the vertical orthographic projection of the first type binding terminal 31 in the first direction X. The second trace 40 is also arranged corresponding to the gap between the second type binding terminals 32. The pressure transmission portion 50 also includes a second pressure transmission sub-portion 52, which is arranged corresponding to the second type binding terminal 32. Optionally, the second pressure transmission sub-portion 52 is integrally formed with the first pressure transmission sub-portion 51, that is, the first pressure transmission sub-portion 51 extends along the first direction X to form the second pressure transmission sub-portion 52.

[0073] A third gap 321 is defined between two adjacent second-type binding terminals 32. The width D1 of the second trace 40 in the second direction Y is less than the distance L3 of the third gap 321. Furthermore, the orthographic projection of the second trace 40 on the substrate layer 10 lies within the orthographic projection of the third gap 321 on the substrate layer 10. In other words, the orthographic projection of the second trace 40 on the substrate layer 10 does not overlap with the orthographic projection of the second-type binding terminal 32 on the substrate layer 10, thereby preventing coupling capacitance between the second trace 40 and the second-type binding terminal 32, thereby preventing any impact on signal transmission by the second-type trace 22.

[0074] Optionally, the width D4 of the second-type binding terminal 32 in the second direction Y ranges from 125 microns to 225 microns, such as 125 microns, 135 microns, 150 microns, 175 microns, 190 microns, 210 microns, or 225 microns. The distance L3 of the third gap 321 ranges from 125 microns to 225 microns, such as 125 microns, 135 microns, 150 microns, 175 microns, 190 microns, 210 microns, or 225 microns. The width D4 of the second-type binding terminal 32 in the second direction Y can be equal to the distance L3 of the third gap 321, such as 175 microns. However, the present application is not limited thereto; the width D4 of the second-type binding terminal 32 in the present application can also be greater than the distance L3 of the third gap 321.

[0075] There is also a fourth gap 404 between two adjacent second traces 40, and the fourth gap 404 is connected to the second gap 403. The second pressure transmission sub-section 52 is located within the fourth gap 404, and the width D5 of the second pressure transmission sub-section 52 in the second direction Y is less than the distance L4 of the fourth gap 404, so as to avoid short circuits between adjacent second traces 40. Furthermore, the second-type binding terminals 32 are arranged corresponding to the fourth gap 404, and the width D4 of the second-type binding terminals 32 in the second direction Y is less than the distance L4 of the fourth gap 404. The orthographic projection of the second-type binding terminals 32 on the substrate layer 10 falls within the range of the orthographic projection of the substrate layer 10, so as to avoid overlapping between the second-type binding terminals 32 and the second traces 40.

[0076] Optionally, the width D5 of the second pressure transmission sub-section 52 in the second direction Y is also smaller than the width D4 of the second type binding terminal 32 in the second direction Y. In the second direction Y, the orthographic projection of the second pressure transmission sub-section 52 on the substrate layer 10 falls within the range of the orthographic projection of the second type binding terminal 32 on the substrate layer 10. Furthermore, the central axis P2 of the second pressure transmission sub-section 52 in the first direction X coincides with the central axis of the second type binding terminal 32 in the first direction X, so that the binding pressure applied to the second pressure transmission sub-section 52 can act on the middle area of ​​the second type binding terminal 32 through the substrate layer 10, thereby avoiding uneven force on the second type binding terminal 32 and causing lateral pressure tilt. It should be noted that since the central axis P2 of the second pressure transmission sub-section 52 in the first direction X coincides with the central axis of the second type binding terminal 32 in the first direction X, the central axis of the second type binding terminal 32 in the first direction X is not shown in Figure 5.

[0077] Next, how to electrically connect the second wiring 40 with the second-type binding terminals 32 and the second-type wiring 22 is described in detail.

[0078] 5 , one end of the second routing line 40 close to the first routing line 20 is electrically connected to the second type routing line 22 through a first via 401, and one end of the second routing line 40 away from the first routing line 20 is electrically connected to the second type binding terminal 32 through a second via 402, and the second routing line 40 is electrically connected to one end of the second type binding terminal 32 away from the first type binding terminal 31.

[0079] Specifically, referring to Figure 6 , the substrate layer 10 includes a first via hole 401 extending through the substrate layer 10. The second trace 40 can be electrically connected to the second trace 40 via a metal connection portion filled in the first via hole 401. The metal connection portion in the first via hole 401 can be formed simultaneously with the second trace 40. The first via hole 401 can be formed in the substrate layer 10 by laser drilling or the like.

[0080] 7 , the substrate layer 10 includes a second via 402 extending through the substrate layer 10 . The second trace 40 can be electrically connected to the second-type binding terminal 32 via a metal connection portion filled in the second via 402 . The metal connection portion in the second via 402 can be formed simultaneously with the second trace 40 . Laser drilling, for example, can be used to form the second via 402 in the substrate layer 10 .

[0081] In this embodiment, referring to FIG8 , the pressure transmission portion 50 is provided at a position corresponding to the first binding terminal 30 . Thus, when the flexible circuit board 100 is bound to the printed circuit board 200 , the pressure transmission portion 50 can apply positive pressure to the first binding terminal 30 through the base material layer 10 . This prevents the first binding terminal 30 from being tilted due to lateral pressure when the first binding terminal 30 of the flexible circuit board 100 is bound to the second binding terminal 201 on the printed circuit board 200 . This alleviates the problem of lateral pressure tilting when the existing flexible circuit board and the printed circuit board are bound together.

[0082] In one embodiment, referring to Figures 2 to 10, Figure 9 is a schematic top view of the pressure transmission portion 50 provided in the embodiment of the present application, and Figure 10 is a schematic cross-sectional view along line Q-Q' in Figure 9. Unlike the above embodiment, the first pressure transmission sub-portion 51 and the second pressure transmission sub-portion 52 are separately provided. The first pressure transmission sub-portion 51 and the second pressure transmission sub-portion 52 are arranged opposite each other, and a gap is formed between the first pressure transmission sub-portion 51 and the second pressure transmission sub-portion 52.

[0083] Specifically, referring to Figure 9 , the first pressure transmission sub-section 51 is provided corresponding to the first type binding terminal 31, the central axis P1 of the first pressure transmission sub-section 51 in the first direction X coincides with the central axis of the first type binding terminal 31 in the first direction X, and the width D3 of the first pressure transmission sub-section 51 in the second direction Y is less than the width D2 of the first type binding terminal 31 in the second direction Y. In some other embodiments, the width D3 of the first pressure transmission sub-section 51 in the second direction Y may also be equal to the width D2 of the first type binding terminal 31 in the second direction Y, so as to better alleviate the problem of lateral pressure tilting of the first type binding terminal 31.

[0084] The central axis P1 of the first pressure transmission sub-section 51 in the second direction Y coincides with the central axis of the first type binding terminal 31 in the second direction Y, and the end of the first pressure transmission sub-section 51 in the first direction X is flush with the end of the first type binding terminal 31 in the first direction X. In other words, the orthographic projection of the first pressure transmission sub-section 51 on the substrate layer 10 coincides with the orthographic projection of the first type binding terminal 31 on the substrate layer 10.

[0085] The second pressure transmission sub-section 52 is provided corresponding to the second type binding terminal 32, and the central axis P2 of the second pressure transmission sub-section 52 in the first direction X coincides with the central axis of the second type binding terminal 32 in the first direction X, and the central axis P2 of the second pressure transmission sub-section 52 in the first direction X coincides with the central axis P1 of the first pressure transmission sub-section 51 in the first direction X. The width D5 of the second pressure transmission sub-section 52 in the second direction Y is less than the width D4 of the second type binding terminal 32 in the second direction Y. In some other embodiments, the width D5 of the second pressure transmission sub-section 52 in the second direction Y may also be equal to the width D4 of the second type binding terminal 32 in the second direction Y, so as to better improve the problem of lateral pressure tilt of the second type binding terminal 32.

[0086] Referring to Figure 10 , a gap exists between the second pressure transmission sub-section 52 and the first pressure transmission sub-section 51. A gap also exists between the second pressure transmission sub-section 52 and the portion electrically connected to the second wiring 40 and the second-type binding terminal 32, to prevent a short circuit between the second pressure transmission sub-section 52 and the second wiring 40. Thus, one end of the second pressure transmission sub-section 52 in the first direction X is flush with one end of the second-type binding terminal 32 in the first direction X, while a certain gap is maintained between the other end of the second pressure transmission sub-section 52 in the first direction X and the second wiring 40. For other explanations, please refer to the above embodiment and will not be repeated here.

[0087] In one embodiment, please refer to Figures 2 to 12, Figure 11 is another schematic diagram of the top view structure of the pressure transmission part 50 provided in the embodiment of the present application, and Figure 12 is a schematic diagram of the cross-sectional structure along R-R' in Figure 11. Different from the above embodiment, referring to Figure 11, the width D3 of the first pressure transmission sub-part 51 in the second direction Y is greater than the width D2 of the first type binding terminal 31 in the second direction Y, and the width D5 of the second pressure transmission sub-part 52 in the second direction Y is greater than the width D4 of the second type binding terminal 32 in the second direction Y. Taking the second pressure transmission sub-part 52 as an example, referring to Figure 12, the width D5 of the second pressure transmission sub-part 52 is greater than the width D4 of the second type binding terminal 32, and the orthographic projection of the second pressure transmission sub-part 52 on the substrate layer 10 covers the orthographic projection of the second type binding terminal 32 on the substrate layer 10. Please refer to the above embodiment for other explanations, which will not be repeated here.

[0088] In one embodiment, referring to Figures 2 to 14, Figure 13 is a schematic diagram of the arrangement of the first-type binding terminals 31 and the second-type binding terminals 32 provided in an embodiment of the present application, and Figure 14 is a schematic diagram of the connection between the second-type binding terminals 32 and the second trace 40 in Figure 13. Unlike the above embodiment, referring to Figure 13, the first-type binding terminals 31 and the second-type binding terminals 32 are arranged in an interlaced manner, that is, the first-type binding terminals 31 are arranged with gaps corresponding to the second-type binding terminals 32, and the second-type binding terminals 32 are arranged with gaps corresponding to the first-type binding terminals 31.

[0089] Referring to Figure 14 , the second trace 40 is electrically connected to an end of the second-type binding terminal 32 proximal to the first-type binding terminal 31. The pressure transmission portion 50 further includes a third pressure transmission sub-portion 53, which is provided corresponding to the second-type binding terminal 32. A central axis P3 of the third pressure transmission sub-portion 53 in the first direction X coincides with the central axis of the second-type binding terminal 32 in the first direction X. For other explanations, please refer to the above embodiment and will not be repeated here.

[0090] In one embodiment, referring to Figures 2 to 15 , Figure 15 is another schematic diagram illustrating the connection between the second-type binding terminal 32 and the second wiring 40 provided in an embodiment of the present application. Unlike the above embodiment, referring to Figure 15 , the second wiring 40 is electrically connected to the end of the second-type binding terminal 32 that is distal from the first-type binding terminal 31 , and the central axis of the second wiring 40 in the first direction X coincides with the central axis of the second-type binding terminal 32 in the first direction X. This eliminates the need for the additional third pressure transmission sub-unit 53. For other explanations, please refer to the above embodiment and will not be repeated here.

[0091] In one embodiment, please refer to Figures 2 to 16. Figure 16 is another schematic diagram of the connection between the second-type binding terminal 32 and the second trace 40 provided in the embodiment of the present application. Different from the above embodiment, referring to Figure 16, the connection points of the second trace 40 and the second-type trace 22 are staggered, that is, the connection points of two adjacent second traces 40 and the corresponding second-type trace 22 do not overlap in the second direction Y. In other words, the connection points of two adjacent second traces 40 and the corresponding second-type trace 22 are at different heights in the first direction X. In this way, by staggering the connection points of the second trace 40 and the second-type trace 22, the contact area of ​​the electrical connection between the second trace 40 and the second-type trace 22 can be increased, thereby improving the stability of the electrical connection between the second trace 40 and the second-type trace 22. Among them, the position of the connection point between the second trace 40 and the second-type trace 22 is the position of the first via 401.

[0092] Moreover, the portion where the second trace 40 is connected to the second type of trace 22 and the portion where the second trace 40 is connected to the second type of binding terminal 32 are both block-shaped. The surface shape of the block can be elliptical, circular, etc., and the maximum size of the block-shaped connection portion is greater than the width of the second trace 40, so as to further improve the connection stability between the second trace 40 and the second type of trace 22 and the second type of binding terminal 32. The maximum size of the block-shaped connection portion depends on the surface shape of the block. For example, when the surface shape of the block is an ellipse, the maximum size of the block-shaped connection portion is the length of the major axis of the ellipse. In addition, the corners where the second trace 40 is electrically connected to the second type of binding terminal 32 are rounded to reduce the bending stress of the second trace 40. For other explanations, please refer to the above embodiments, which will not be repeated here.

[0093] In one embodiment, the present application further provides a display module. Referring to Figures 2 to 18, Figure 17 is a schematic top view of the display module provided in an embodiment of the present application, and Figure 18 is a schematic diagram of the arrangement of second binding terminals on the printed circuit board in Figure 17. Referring to Figure 17, the display module 1000 includes a display panel 300, a printed circuit board 200, and a flexible circuit board 100 electrically connected between the display panel 300 and the printed circuit board 200. The flexible circuit board 100 is the flexible circuit board 100 described in one of the aforementioned embodiments. The printed circuit board 200 includes a second binding region 202 opposite the first binding region 112 of the flexible circuit board 100. The printed circuit board 200 is provided with a plurality of second binding terminals 201 in the second binding region 202. The second binding terminals 201 are bound to corresponding first binding terminals 30 on the flexible circuit board 100.

[0094] Specifically, in combination with reference to Figures 3 and 18, the second binding terminal 201 includes a third type binding terminal 2011 and a fourth type binding terminal 2012 that are electrically isolated from each other, the third type binding terminal 2011 is bound to the first type binding terminal 31 on the flexible circuit board 100, and the fourth type binding terminal 2012 is bound to the second type binding terminal 32 on the flexible circuit board 100.

[0095] Further, referring to FIG8 , the orthographic projection of the first binding terminal 30 on the printed circuit board 200 is within the orthographic projection of the corresponding second binding terminal 201 on the printed circuit board 200, thereby ensuring sufficient effective contact surface between the first binding terminal 30 and the second binding terminal 201. Furthermore, the orthographic projection of the portion of the pressure transmission portion 50 corresponding to the first binding terminal 30 on the substrate layer 10 falls within the orthographic projection of the corresponding first binding terminal 30 on the substrate layer 10. Thus, the orthographic projection of the portion of the pressure transmission portion 50 corresponding to the first binding terminal 30 on the printed circuit board 200 is within the orthographic projection of the corresponding second binding terminal 201 on the printed circuit board 200.

[0096] Optionally, the central axis of the first binding terminal 30 coincides with the central axis of the corresponding second binding terminal 201. At the same time, the central axis of the first binding terminal 30 also coincides with the central axis of the corresponding pressure transmission part 50, so that the binding pressure applied to the pressure transmission part 50 can act on the middle area of ​​the corresponding first binding terminal 30 through the substrate layer 10, and the binding pressure acting on the middle area of ​​the first binding terminal 30 can be transmitted to the middle area of ​​the corresponding second binding terminal 201, so that the first type binding terminal 31 and the second binding terminal 201 are effectively bound together. This can further avoid the first type binding terminal 31 from being tilted by lateral pressure compared to the second binding terminal 201, which leads to abnormal pressing impedance of the binding area and abnormal reliability test.

[0097] Continuing with FIG. 17 , the flexible circuit board 100 further includes a third bonding area 113 opposite the first bonding area 112. The third bonding area 113 is bonded to the fourth bonding area 301 on the display panel 300. Specifically, the third bonding terminal of the third bonding area 113 of the flexible circuit board 100 is bonded to the fourth bonding terminal of the fourth bonding area 301 of the display panel 300. A driver integrated circuit (IC) 400 is also bonded to the fourth bonding area 301 of the display panel 300. The flexible circuit board 100 transmits signals from the printed circuit board 200 to the driver IC 400. The display panel 300 may include an organic light-emitting diode display panel, a liquid crystal display panel, or the like.

[0098] Based on the same inventive concept, an embodiment of the present application further provides an electronic device, which includes the display module 1000 of the aforementioned embodiment. The electronic device includes electronic display devices such as laptops, tablets, and televisions.

[0099] According to the above embodiments, it can be seen that:

[0100] The present application provides a flexible circuit board, a display module and an electronic device, wherein the flexible circuit board includes a substrate layer, a plurality of first traces and a plurality of first binding terminals arranged on a first surface of the substrate layer, and a plurality of second traces and a plurality of pressure transmission parts arranged on a second surface of the substrate layer, the first surface includes a trace area and a first binding area located on one side of the trace area, a plurality of first traces are located in the trace area, a plurality of first traces extend along a first direction and are spaced apart along a second direction, and a plurality of first traces include first-type traces and second-type traces that are electrically isolated from each other, a plurality of first binding terminals are located in the first binding area, a plurality of first binding terminals extend along the first direction and are spaced apart along the second direction, and a plurality of first binding terminals include first-type binding terminals and second-type binding terminals that are electrically isolated from each other, and a plurality of second-type binding terminals The terminal is located on the side of the first type binding terminal away from the first wiring, each first type binding terminal is electrically connected to at least one first type wiring, each second type binding terminal is electrically connected to at least one second type wiring, multiple second wirings are arranged corresponding to the gaps of the first type binding terminals, each second wiring is electrically connected between the second type wiring and the second type binding terminal, and each pressure transmission part includes at least a part corresponding to at least part of the first binding terminal, so that the pressure transmission part can transmit pressure to the first binding terminal through the substrate layer. In this way, when the flexible circuit board is bound to the printed circuit board, the pressure transmission part can apply positive pressure to the binding terminal through the substrate layer, avoiding lateral pressure tilt of the binding terminal, and alleviating the technical problem of lateral pressure tilt when the existing flexible circuit board and printed circuit board are bound.

[0101] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] The above is a detailed introduction to the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A flexible circuit board, comprising: The substrate layer comprises a first surface and a second surface opposite to each other, wherein the first surface comprises a wiring area and a first binding area located at one side of the wiring area; A plurality of first routing lines are arranged on the first surface and located in the routing area, the plurality of first routing lines extend along a first direction and are arranged at intervals along a second direction, and the plurality of first routing lines include first-type routing lines and second-type routing lines that are electrically isolated from each other; A plurality of first binding terminals are arranged on the first surface and located in the first binding area, the plurality of first binding terminals extend along the first direction and are arranged at intervals along the second direction, and the plurality of first binding terminals include first-type binding terminals and second-type binding terminals that are electrically isolated from each other, the second-type binding terminals are located on a side of the first-type binding terminals away from the first wiring, each of the first-type binding terminals is electrically connected to at least one of the first-type wirings, and each of the second-type binding terminals is electrically connected to at least one of the second-type wirings; A plurality of second wirings are arranged on the second surface and are arranged corresponding to the gaps between the first type binding terminals, and each of the second wirings is electrically connected between the second type wiring and the second type binding terminal; as well as A plurality of pressure transmission parts are arranged on the second surface, and each of the pressure transmission parts at least includes a portion corresponding to at least a portion of the first binding terminal, so that the pressure transmission part can transmit pressure to the first binding terminal through the substrate layer.

2. The flexible circuit board according to claim 1, wherein: An elastic modulus of the pressure transmission portion is greater than or equal to an elastic modulus of the second wiring.

3. The flexible circuit board according to claim 2, wherein: The material of the pressure transmission portion is the same as that of the second wiring.

4. The flexible circuit board according to claim 2, wherein: In a direction perpendicular to the substrate layer, the thickness of the pressure transmission portion is greater than or equal to the thickness of the second wiring.

5. The flexible circuit board according to claim 1, wherein: There is a first gap between two adjacent first-type binding terminals, the width of the second trace in the second direction is smaller than the distance of the first gap, and the orthographic projection of the second trace on the substrate layer is within the range of the orthographic projection of the first gap on the substrate layer.

6. The flexible circuit board according to claim 1, wherein: The flexible circuit board further comprises a covering layer, wherein the covering layer covers the second trace, the pressure transmission part and the substrate layer; The thickness of the covering layer covering the second trace is smaller than the thickness of the covering layer covering the substrate layer.

7. The flexible circuit board according to claim 1, wherein: The pressure transmission portion includes a first pressure transmission sub-portion, and the first pressure transmission sub-portion is located between two adjacent second wirings and is arranged corresponding to the first type binding terminal.

8. The flexible circuit board according to claim 7, wherein: A second gap is provided between two adjacent second wirings, the first pressure transmission sub-portion is located in the second gap, and a width of the first pressure transmission sub-portion in the second direction is smaller than a distance of the second gap.

9. The flexible circuit board according to claim 8, wherein: A central axis of the first pressure transmission sub-portion in the first direction coincides with a central axis of the first type binding terminal in the first direction.

10. The flexible circuit board according to claim 7, wherein: The first type of binding terminals are arranged opposite to the second type of binding terminals, and the second wiring is also arranged corresponding to the gap of the second type of binding terminals. The pressure transmission part also includes a second pressure transmission sub-part, and the second pressure transmission sub-part is arranged corresponding to the second type of binding terminals; the second wiring is electrically connected to one end of the second type of binding terminal away from the first type of binding terminal.

11. The flexible circuit board according to claim 10, wherein: There is a third gap between the two adjacent second-type binding terminals, the width of the second trace in the second direction is smaller than the distance of the third gap, and the orthographic projection of the second trace on the substrate layer is within the range of the orthographic projection of the third gap on the substrate layer.

12. The flexible circuit board according to claim 11, wherein: There is a fourth gap between the two adjacent second wirings, the second pressure transmission sub-portion is located in the fourth gap, and the width of the second pressure transmission sub-portion in the second direction is smaller than the distance of the fourth gap.

13. The flexible circuit board according to claim 12, wherein: The central axis of the second pressure transmission sub-portion in the first direction coincides with the central axis of the second-type binding terminal in the first direction.

14. The flexible circuit board according to claim 7, wherein: The first type of binding terminals and the second type of binding terminals are arranged alternately, and the second wiring is electrically connected to one end of the second type of binding terminals close to the first type of binding terminals; the pressure transmission part also includes a third pressure transmission sub-part, and the third pressure transmission sub-part is arranged corresponding to the second type of binding terminals; the central axis of the third pressure transmission sub-part in the first direction coincides with the central axis of the second type of binding terminals in the first direction.

15. The flexible circuit board according to claim 7, wherein: The first type of binding terminals and the second type of binding terminals are arranged alternately, the second wiring is electrically connected to one end of the second type of binding terminals away from the first type of binding terminals, and the central axis of the second wiring in the first direction coincides with the central axis of the second type of binding terminals in the first direction.

16. A display module, comprising a display panel, a printed circuit board, and a flexible circuit board electrically connected between the display panel and the printed circuit board, wherein the flexible circuit board comprises the flexible circuit board according to claim 1; wherein: The printed circuit board includes a second binding area opposite to the first binding area of ​​the flexible circuit board. The printed circuit board is provided with a plurality of second binding terminals in the second binding area. The second binding terminals are bound to the corresponding first binding terminals on the flexible circuit board.

17. The display module according to claim 16, wherein: The orthographic projection of the first binding terminal on the printed circuit board is located within the orthographic projection range of the corresponding second binding terminal on the printed circuit board.

18. The display module according to claim 17, wherein: The orthographic projection of the pressure transmission portion corresponding to the first binding terminal on the printed circuit board is located within the orthographic projection range of the corresponding second binding terminal on the printed circuit board.

19. The display module according to claim 17, wherein: The second binding terminals include a third type of binding terminals and a fourth type of binding terminals which are electrically isolated from each other. The third type of binding terminals are bound to the first type of binding terminals on the flexible circuit board, and the fourth type of binding terminals are bound to the second type of binding terminals on the flexible circuit board.

20. An electronic device comprising the display module as claimed in claim 16.

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