Flexible circuit boards, display modules and display devices

Abstract

This application provides a flexible circuit board, a display module, and a display device. The flexible circuit board includes: a first shielding layer, a first signal trace and a combination layer, a second signal trace, and a second shielding layer stacked together. The combination layer includes a first design potential trace and a third signal trace disposed on the same layer. The orthogonal projection of the second signal trace onto the combination layer does not exceed the range of the first design potential trace. The second shielding layer is disposed on the side of the second signal trace away from the combination layer and covers the combination layer. This application provides a new second signal trace by rerouting the second initial signal trace within a newly added local trace structure, and using the film structure of the original second initial signal trace as the first design potential trace. This ensures that the second signal trace is not interfered with by other signals and eliminates the need to add a full ground layer or other protective devices to the original second initial signal trace, thereby reducing the number of layers in the flexible circuit board and making it thinner and lighter.

Description

Technical Field

[0001] This application relates to the field of flexible circuit board technology, and more specifically, to a flexible circuit board, a display module, and a display device. Background Technology

[0002] With the continuous development of display technology, users have increasingly higher requirements for display resolution, refresh rate, and other aspects. The higher the performance requirements and the more comprehensive the functional requirements of display devices, the more traces are laid on the flexible circuit boards inside the display devices, resulting in an overall thickness and making the display devices relatively bulky.

[0003] Therefore, flexible circuit boards can adopt a multi-layer board structure. However, when the size of the flexible circuit board is large, the signal traces are integrated in a flexible circuit board and are close to each other, which often causes signal interference and other problems. Therefore, it is necessary to add some protective devices near each signal trace to improve the electromagnetic interference resistance of each signal trace and avoid excessive electromagnetic radiation from each signal trace that causes mutual interference, which further increases the thickness of the flexible circuit board. Summary of the Invention

[0004] This application addresses the shortcomings of existing methods by proposing a flexible circuit board, a display module, and a display device to solve the technical problem of the excessive thickness of flexible circuit boards in the prior art.

[0005] In a first aspect, embodiments of this application provide a flexible circuit board, comprising: a first shielding layer, a first signal trace and a combined layer, and a second signal trace and a second shielding layer on the side of the combined layer away from the first signal trace;

[0006] The composite layer includes a first design potential trace and a third signal trace arranged on the same layer;

[0007] The orthogonal projection of the second signal trace onto the composite layer does not exceed the range of the first design potential trace.

[0008] The second shielding layer is located on the side of the second signal trace away from the composite layer and covers the composite layer.

[0009] Optionally, the flexible circuit board further includes: a first cover film, a first adhesive structure, and a second cover film;

[0010] The first cover film is located between the first signal trace and the first shielding layer;

[0011] The first adhesive structure is located between the first design potential trace and the second signal trace;

[0012] The second cover film is located between the third signal trace and the second shielding layer;

[0013] The first adhesive structure and the second cover film are disposed in the same layer.

[0014] Optionally, the first adhesive structure includes: a first substrate and an adhesive structure encapsulating the first substrate.

[0015] Optionally, the flexible circuit board further includes a third cover film located between the second signal trace and the second shielding layer.

[0016] Optionally, the second signal trace includes at least one of a touch drive line, a touch sensing line, a display communication signal line, or a power signal line.

[0017] Optionally, the second signal trace includes a touch driving line and a touch sensing line; the flexible circuit board also includes a pin assembly exposed to the second shielding layer;

[0018] One set of pins of the pin assembly is electrically connected to the touch drive line, and another set of pins is electrically connected to the touch sensing line;

[0019] The pin assembly does not overlap with the touch drive line and touch sensing line in the direction perpendicular to the flexible circuit board.

[0020] Optionally, the flexible circuit board may also include: a chip;

[0021] The touch driving line and the touch sensing line are electrically connected to the chip respectively;

[0022] On the first shielding layer, the orthographic projection of the chip is located in the middle region of the first shielding layer, and the orthographic projections of the touch driving line and the touch sensing line are located in the edge region of the first shielding layer.

[0023] Optionally, the flexible circuit board further includes: a second design potential trace and a fourth signal trace, which are stacked between the second signal trace and the second shielding layer in a direction away from the second signal trace;

[0024] The orthogonal projection of the second signal trace onto the second design potential trace does not exceed the range of the second design potential trace.

[0025] Secondly, embodiments of this application also provide a display module, including: a display panel and any of the flexible circuit boards provided in the first aspect above.

[0026] Thirdly, embodiments of this application also provide a display device, including: a display module as provided in the second aspect above.

[0027] The beneficial technical effects of the technical solutions provided in this application include:

[0028] In related technologies, the second initial signal trace of a flexible circuit board is locally present and is set on the same layer as the third signal trace. In this embodiment, a local trace structure occupying only a small area is added above the original locally present second initial signal trace of the flexible circuit board. The second initial signal trace is re-run in the newly added local trace structure as a new second signal trace. The film layer structure of the original second initial signal trace is used as the first design potential trace. The first design potential trace is set on the same layer as the third signal trace, so that the new second signal trace corresponds completely with the first design potential trace. Furthermore, the second shielding layer can cover the new second signal trace, ensuring that the second signal trace is not interfered with by other signals. It is also unnecessary to add a whole ground layer or other protection devices to the original second initial signal trace, thereby reducing the number of layers of the flexible circuit board and making the flexible circuit board thinner and lighter.

[0029] Furthermore, the newly added second signal trace is localized, with fewer layers and a thinner thickness compared to the entire flexible circuit board. Its lower step difference from the large flat area of ​​the flexible circuit board ensures the reliability of the second shielding layer. It can also be manufactured using existing wiring processes for flexible circuit boards, keeping costs under control.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0032] Figure 1 A cross-sectional schematic diagram of a flexible circuit board structure provided in an embodiment of this application;

[0033] Figure 2 A cross-sectional schematic diagram of another flexible circuit board structure provided in an embodiment of this application;

[0034] Figure 3 A cross-sectional schematic diagram of another flexible circuit board structure provided in an embodiment of this application;

[0035] Figure 4 This is a top view schematic diagram of the structure of a flexible circuit board provided in an embodiment of this application.

[0036] Figure label:

[0037] 100 - Flexible circuit board;

[0038] 110 - First shielding layer; 120 - First signal trace;

[0039] 130 - Composite layer; 131 - First design potential trace; 132 - Third signal trace;

[0040] 140 - Second signal trace;

[0041] 150 - Second shielding layer;

[0042] 160 - First cover film; 170 - First adhesive structure; 180 - Second cover film; 190 - Third cover film;

[0043] 101 - Pin assembly; 102 - Chip; 103 - Second design potential trace; 104 - Fourth signal trace;

[0044] 105 - Electronic Components Area. Detailed Implementation

[0045] The embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the embodiments described below with reference to the accompanying drawings are exemplary descriptions for explaining the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions of the embodiments of this application.

[0046] Those skilled in the art will understand that, unless otherwise stated, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be understood that when we say an element is “connected” or “coupled” to another element, the element may be directly connected or coupled to the other element, or it may mean that the element and the other element are connected through an intermediate element. The term “and / or” as used herein refers to at least one of the items defined by the term; for example, “A and / or B” can be implemented as “A,” or as “B,” or as “A and B.”

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0048] In related technologies, some signal traces exist locally within flexible circuit boards. Their characteristic impedance is generally calculated with reference to the design potential traces (ground plane or power plane; the signal on the ground plane is also called the reference "ground," which is the reference point of zero potential and also the common terminal of the circuit signal loop. The signal on the power plane serves to supply power to the power plane). If there are continuous design potential traces near the signal trace, the impedance continuity is ensured, thereby ensuring the integrity or quality of signal transmission of the signal trace.

[0049] Generally, in order to facilitate the provision of zero potential reference for signal traces, a whole layer of design potential layer (ground layer) is directly covered on the signal traces, resulting in low space utilization inside the flexible circuit board and a relatively thick overall thickness, which is not conducive to the development of thinner and lighter display devices.

[0050] For example, in related technologies, the second initial signal trace and the third signal trace are set on the same layer. There may be other signal traces, which will not be listed here. These signal traces all run on the same layer inside the flexible circuit board. The second initial signal trace has high requirements for signal transmission quality, so it is necessary to protect the second initial signal trace from interference. The general solution is to add a whole ground layer directly above the film layer structure where the second initial signal trace and the third signal trace are located. This results in a thicker flexible display panel.

[0051] The flexible circuit board 100, display module, and display device provided in this application are intended to solve the above-mentioned technical problems of the prior art.

[0052] The technical solution of this application and how it solves the above-mentioned technical problems are described in detail below with specific embodiments. It should be noted that the following embodiments can be referenced, borrowed, or combined with each other, and the same terms, similar features, and similar implementation steps in different embodiments will not be described again.

[0053] Please refer to Figure 1 This application provides a flexible circuit board 100, including: a first shielding layer 110, a first signal trace 120 and a combined layer 130, and a second signal trace 140 and a second shielding layer 150 on the side of the combined layer 130 away from the first signal trace 120.

[0054] The composite layer 130 includes a first design potential trace 131 and a third signal trace 132 disposed on the same layer.

[0055] The orthogonal projection of the second signal trace 140 onto the composite layer 130 does not exceed the range of the first design potential trace 131.

[0056] The second shielding layer 150 is disposed on the side of the second signal trace 140 away from the composite layer 130 and covers the composite layer 130.

[0057] In this embodiment, by adding a small-area local trace structure to the existing local second initial signal trace on the flexible circuit board 100, the second initial signal trace is re-run in the newly added local trace structure as a new second signal trace 140. The film structure of the original second initial signal trace is used as the first design potential trace 131. The first design potential trace 131 and the third signal trace 132 are set on the same layer, so that the new second signal trace 140 completely corresponds to the first design potential trace 131, isolating the first signal trace 120 and the second signal trace 140. Furthermore, the second shielding layer 150 can cover the new second signal trace 140, ensuring that the second signal trace 140 is not interfered with by other signals. It is also unnecessary to add a whole ground layer or other protective devices to the original second initial signal trace, thereby reducing the number of layers of the flexible circuit board 100, making the flexible circuit board 100 thinner and lighter, and reducing the manufacturing cost of the flexible circuit board 100.

[0058] The second signal trace 140 is close to the first design potential trace 131, that is, the second signal trace 140 is close to the design potential plane (ground plane), which can play a role in shielding and providing return current nearby, so that the return current area of ​​the second signal trace 140 loop is small, ensuring good signal quality.

[0059] Furthermore, the newly added second signal trace 140 is locally present, with fewer layers and a thinner thickness compared to the entire flexible circuit board 100. Its lower step difference from the flat area of ​​the flexible circuit board 100 ensures the reliability of the second shielding layer 150. It can also be manufactured using the existing trace fabrication process of the flexible circuit board 100, keeping costs under control.

[0060] It is understandable that the flat area of ​​the flexible circuit board 100 is the area in the flexible circuit board 100 where no new local wiring structure has been added.

[0061] Optionally, the second signal trace 140 is a high-frequency (frequency exceeding the design frequency) signal trace.

[0062] Optionally, the first design potential trace 131 includes at least one of ground trace, power trace, or other traces that transmit low potential signals. When necessary, it can also be a ground plane (ground layer) or power layer, which can completely cover one side of the second signal trace 140, avoid spatial overlap with other signal traces, and prevent electromagnetic interference between the second signal trace 140 and other signal traces, thereby affecting the signal transmission quality.

[0063] Optionally, the area of ​​the second signal trace 140 can be made larger than that of the second initial signal trace, depending on actual needs, thereby increasing the area of ​​the second signal trace 140 and reducing the interference of signals from other signal traces on the signal transmission of the second signal trace 140.

[0064] Optionally, there may be at least one other signal trace between the first signal trace 120 and the combination layer 130. The type of flexible circuit board 100 (such as a two-layer board, a four-layer board, or a six-layer board, etc.) is selected according to the actual number of signal trace layers.

[0065] Optionally, in this embodiment, the first signal trace 120, the second signal trace 140, the third signal trace 132, and the fourth signal trace 104 are provided with insulating layers on both sides to isolate each signal trace. This is a conventional design in related technologies and will not be described in detail here.

[0066] In some possible implementations, such as Figure 2 As shown, the flexible circuit board 100 also includes: a first cover film 160, a first adhesive structure 170, and a second cover film 180.

[0067] The first cover film 160 is located between the first signal trace 120 and the first shielding layer 110.

[0068] The first adhesive structure 170 is located between the first design potential trace 131 and the second signal trace 140.

[0069] The second cover film 180 is located between the third signal trace 132 and the second shielding layer 150.

[0070] The first adhesive structure 170 and the second cover film 180 are disposed in the same layer.

[0071] In this embodiment, the first cover film 160 can protect the first signal trace 120 and improve the bending performance of the flexible circuit board 100 on the side where the first signal trace 120 is located. Using the first adhesive structure 170 to bond the newly added second signal trace 140 and the first design potential trace 131 (e.g., ground trace, power line or other traces transmitting low potential signals) is less costly and can improve the feasibility of the embodiments of this application.

[0072] Since there are no other signal traces above the third signal trace 132, the third signal trace 132 is equivalent to the top layer signal trace in the large-area flat area of ​​the flexible circuit board 100. The second cover film 180 is then set above the third signal trace 132 to protect the third signal trace 132, thereby improving the bending performance of the flexible circuit board 100 on the side where the third signal trace 132 is located.

[0073] In related technologies, the second cover film 180 needs to cover an entire composite layer 130. In this embodiment, the cover film between the first design potential trace 131 and the second signal trace 140 can be eliminated, so that the newly added local trace structure is not too thick.

[0074] Optionally, the first signal trace 120 may include multiple sub-signal traces arranged on the same layer, which can be designed according to actual needs.

[0075] Optionally, the signal traces in this embodiment can be fabricated using a flexible copper clad laminate (FCCL). For example, the first signal trace 120 in this embodiment can be fabricated using a first FCCL, and the composite layer 130 can be fabricated using a second FCCL. The first and second FCCLs are then bonded together using a bonding adhesive, and the necessary protective structures are fabricated on the unbonded side to obtain the flexible circuit board 100. However, the second signal trace 140 in this embodiment does not need to be fabricated using a whole FCCL; it only needs to be added locally, which is equivalent to reducing the number of large-area stacked layers in the flexible circuit board 100, thereby reducing manufacturing costs.

[0076] Optionally, the flexible circuit board 100 of this application can be applied to single-sided boards, double-sided boards, multi-layer boards and other types of flexible circuit boards 100 in related technologies. It is only necessary to redesign the second initial signal trace in the original flexible circuit board 100 of each type into the newly added local trace structure, and change the position of the original second initial signal trace to the first design potential trace 131.

[0077] In some possible implementations, the first adhesive structure 170 includes: a first substrate and an adhesive structure encapsulating the first substrate.

[0078] In this embodiment, the second signal trace 140 in the newly added local trace structure and the first design potential trace 131 in the composite layer 130 are bonded together using a first adhesive structure 170. The first adhesive structure 170 can be a structure with aluminum foil composite cloth as the first substrate and a high-performance special thermal adhesive uniformly coated on it, exhibiting high peel strength, good initial tack, excellent cohesion, and good weather resistance. The thermal adhesive is relatively sensitive to heat, exhibiting tackiness under heating conditions, and can bond the local trace structure and the composite layer 130 after cooling. The material is readily available, the method is simple, and it is easy to implement.

[0079] In some possible implementations, such as Figure 2 As shown, the flexible circuit board 100 also includes a third cover film 190, located between the second signal trace 140 and the second shielding layer 150.

[0080] In this embodiment, a third cover film 190 can be added to the second signal trace 140 to protect the circuit structure of the second signal trace 140 and improve the reliability of the second signal trace 140.

[0081] Optionally, the cover films provided in the embodiments of this application are polyimide cover films with a specification of 1 / 2 mil or 1 mil, which are very thin and have little impact on the overall thickness of the flexible circuit board 100.

[0082] In some possible implementations, the second signal trace 140 includes at least one of a touch drive line 141, a touch sensing line 141, a display communication signal line, or a power signal line.

[0083] In this embodiment, the second signal trace 140 can be one type of signal trace or multiple types of signal traces, located at multiple local locations of the flexible circuit board 100. In this embodiment, local trace structures are added to the areas involving these signal traces, and the signal traces are run in the local trace structures. The original trace locations are used as the first design potential trace 131 to reduce the number of protection devices introduced due to anti-interference, thereby reducing the number of layers of the flexible circuit board 100.

[0084] In some possible implementations, refer to Figure 4 The second signal trace 140 includes a touch driving line and a touch sensing line. The flexible circuit board 100 also includes a pin assembly 101 exposed to the second shielding layer 150.

[0085] A portion of the pins of the pin assembly 101 are electrically connected to the touch drive line, and another portion of the pins are electrically connected to the touch sensing line.

[0086] The pin assembly 101 does not overlap with the touch driving line and the touch sensing line in the direction perpendicular to the flexible circuit board 100.

[0087] The signals transmitted via touch communication signal traces are particularly sensitive. These traces can include touch driving lines and touch sensing lines, requiring design potential traces on both sides. For large and medium-sized flexible circuit boards 100, the large number of touch driving lines and touch sensing lines necessitates a large ground plane area, often requiring an additional ground layer. In this embodiment, only local trace structures need to be added to the sensitive parts involving these signals, and these signals can be routed within these new local trace structures. This ensures the electromagnetic shielding performance of the touch driving lines and touch sensing lines while reducing the thickness of the flat area of ​​the flexible circuit board 100, which is beneficial for the overall terminal design.

[0088] In this embodiment, most of the touch driving lines and touch sensing lines are located at both ends of the pin assembly 101, and the newly added local wiring structure will not affect the position of the pin assembly 101. In this embodiment, the direction perpendicular to the flexible circuit board 100 refers to the direction perpendicular to the flexible circuit board 100 in its flat state.

[0089] The second signal trace 140 consists of a touch drive line and a touch sensing line. Figure 4 In this section, it is not specified which part is the touch drive line and which part is the touch sensing line; technical personnel can set it according to the actual situation.

[0090] In some possible implementations, refer to Figure 4 The flexible circuit board 100 also includes a chip 102.

[0091] The touch driving line and the touch sensing line are electrically connected to chip 102 respectively.

[0092] On the first shielding layer 110, the orthographic projection of the chip 102 is located in the middle region of the first shielding layer 110, and the orthographic projections of the touch driving line and the touch sensing line are located in the edge region of the first shielding layer 110.

[0093] Figure 4 The diagram shows a top view of the structure of the flexible circuit board 100 provided in an embodiment of this application. The chip 102 is located in the internal region of the flexible circuit board 100, while the pins in the pin assembly 101 are arranged in different regions. The touch driving line and the touch sensing line are located at both ends of at least some of the pin regions.

[0094] In this embodiment, the pin assembly 101 is generally located in the edge region of the flexible circuit board 100, and is spaced from the region where the chip 102 is located in a direction perpendicular to the flexible circuit board 100. The touch driving line and the touch sensing line are connected to the chip 102 at a relatively long distance. By adopting the local routing structure provided in this application, their routing is re-run in the newly added local routing structure, which reduces the thickness of the flat area of ​​the flexible circuit board 100 while ensuring electromagnetic isolation from other signal routing lines.

[0095] Understandable, Figure 4 For ease of understanding, the second shielding layer 150 on the top layer has been removed. In actual practice... Figure 4 The flexible circuit board 100 shown also includes a second shielding layer 150.

[0096] Optionally, Figure 4 The dashed lines in the diagram represent the wiring used for electrical connections in the flexible circuit board 100.

[0097] Alternatively, please refer to Figure 4 The flexible circuit board 100 also includes an electronic component area 105, which includes basic components such as capacitors, resistors, and diodes that constitute the flexible circuit board 100.

[0098] Optionally, the electronic component area 105 is disposed on a reinforcing member, which can be made of steel sheet and can be used to weld electronic components or compensate for the strength of the relatively soft flexible circuit board 100.

[0099] In some possible implementations, such as Figure 3 As shown, the flexible circuit board 100 also includes a second design potential trace 103 and a fourth signal trace 104, which are stacked between the second signal trace 140 and the second shielding layer 150 in a direction away from the second signal trace 140.

[0100] The orthogonal projection of the second signal trace 140 onto the second design potential trace 103 does not exceed the range of the second design potential trace 103.

[0101] In this embodiment, some fourth signal traces 104 can also be routed within the newly added local trace structure, eliminating the need to design fourth signal traces 104 in the flat area of ​​the flexible circuit board 100. This results in only an increase in the thickness of the local trace structure. When the display device performs operations such as bending the flexible circuit board 100, the internal space of the display device can be utilized to avoid the local trace structure, thus making reasonable use of the internal space of the display device. Furthermore, after adding the fourth signal trace 104, a second design potential trace 103 needs to be added between the second signal trace 140 and the fourth signal trace 104, ensuring that there are design potential traces on both sides of the second signal trace 140, guaranteeing the signal transmission quality of the second signal trace 140.

[0102] Based on the same inventive concept, this application also provides a display module, including: a display panel and any of the flexible circuit boards 100 provided in the foregoing embodiments.

[0103] The display module provided in this embodiment includes any of the flexible circuit boards 100 provided in the above embodiments, and their implementation principles are similar, so they will not be described again here.

[0104] Optionally, the touch driving line and touch sensing line of the flexible circuit board 100 are electrically connected to the touch panel in the display panel.

[0105] Based on the same inventive concept, embodiments of this application also provide a display device, including: a display module as provided in the foregoing embodiments.

[0106] The display device provided in this embodiment includes any of the display modules provided in the above embodiments, and their implementation principles are similar, so they will not be described again here.

[0107] By applying some embodiments of this application, at least the following beneficial effects can be achieved:

[0108] 1. By adding a small-area local trace structure to the existing local second initial signal trace on the flexible circuit board 100, the second initial signal trace is re-run in the newly added local trace structure as a new second signal trace 140. The film layer structure of the original second initial signal trace is used as the first design potential trace 131. The first design potential trace 131 and the third signal trace 132 are set on the same layer, so that the new second signal trace 140 corresponds completely to the first design potential trace 131, isolating the first signal trace 120 and the second signal trace 140. Furthermore, the second shielding layer 150 can cover the new second signal trace 140, ensuring that the second signal trace 140 is not interfered with by other signals. It is also unnecessary to add a whole ground layer or other protection devices to the original second initial signal trace, thereby reducing the number of layers of the flexible circuit board 100, making the flexible circuit board 100 thinner and lighter, and reducing the manufacturing cost of the flexible circuit board 100.

[0109] 2. The first cover film 160 can protect the first signal trace 120 and improve the bending performance of the flexible circuit board 100 on the side where the first signal trace 120 is located. Using the first adhesive structure 170 to bond the newly added second signal trace 140 and the first design potential trace 131 is low-cost and can improve the feasibility of the embodiments of this application.

[0110] 3. The second signal trace 140 of the newly added local trace structure is bonded to the first design potential trace 131 of the composite layer 130 using a first adhesive structure 170. The first adhesive structure 170 can be a structure with aluminum foil composite cloth as the first substrate, uniformly coated with a high-performance special thermal adhesive, which has high peel strength, good initial tack, excellent cohesion, and good weather resistance. The thermal adhesive is relatively sensitive to heat, exhibiting tackiness when heated, and can bond the local trace structure and the composite layer 130 after cooling. The material is readily available, the method is simple, and it is easy to implement.

[0111] 4. For large and medium-sized flexible circuit boards 100, the excessive number of touch driving lines and touch sensing lines necessitates a large ground plane area, often requiring the addition of an entire ground layer. In this embodiment, only a new local routing structure needs to be added to the sensitive parts involving these signals, and these signals can be routed within the newly added local routing structure. This ensures both the electromagnetic shielding performance of the touch driving lines and touch sensing lines and reduces the thickness of the flat area of ​​the flexible circuit board 100 (where no new local routing structure is added), which is beneficial for the overall terminal design.

[0112] 5. Depending on the actual situation, some fourth signal traces 104 can also be routed within the newly added local trace structure, eliminating the need to design fourth signal traces 104 in the flat area of ​​the flexible circuit board 100. This results in only an increase in the thickness of the local trace structure. When the display device performs operations such as bending the flexible circuit board 100, the internal space of the display device can be utilized to avoid the local trace structure, making reasonable use of the internal space of the display device. Furthermore, after adding the fourth signal trace 104, a second design potential trace 103 needs to be added between the second signal trace 140 and the fourth signal trace 104, ensuring that there are design potential traces on both sides of the second signal trace 140, guaranteeing the signal transmission quality of the second signal trace 140.

[0113] In the description of this application, the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate directions or positional relationships based on the exemplary directions or positional relationships shown in the accompanying drawings. They are used to facilitate the description or simplification of the embodiments of this application and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0114] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0115] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0116] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0117] The above description is only a partial implementation of this application. It should be noted that for those skilled in the art, other similar implementation methods based on the technical concept of this application, without departing from the technical concept of this application, also fall within the protection scope of the embodiments of this application.

Claims

1. A flexible circuit board, characterized by, The flexible circuit board comprises: a first shielding layer, a first signal trace and a combination layer, the combination layer comprising a first design potential trace and a third signal trace arranged in the same layer; a second signal trace, a projection of the second signal trace on the combination layer corresponding to the first design potential trace completely; a second shielding layer arranged on a side of the second signal trace away from the combination layer and covering the combination layer; the second signal trace comprising a touch driving line and a touch sensing line; the flexible circuit board further comprises: a pin assembly exposed on the second shielding layer; a part of the pin assembly is electrically connected to the touch driving line, and another part of the pin assembly is electrically connected to the touch sensing line; the pin assembly, the touch driving line and the touch sensing line do not overlap in a direction perpendicular to the flexible circuit board; the flexible circuit board further comprises: a chip; 2. The flexible circuit board of claim 1, wherein, the touch driving line and the touch sensing line are electrically connected to the chip respectively; on the first shielding layer, a projection of the chip is located in a middle region of the first shielding layer, and projections of the touch driving line and the touch sensing line are located in edge regions of the first shielding layer. The flexible circuit board further comprises: a first cover film between the first signal trace and the first shielding layer; a first adhesive structure between the first design potential trace and the second signal trace; 3. The flexible circuit board of claim 2, wherein, a second cover film between the third signal trace and the second shielding layer; 4. The flexible circuit board of claim 1, wherein, the first adhesive structure and the second cover film are arranged in the same layer.

5. The flexible circuit board of claim 1, wherein, The first adhesive structure comprises: a first base material and an adhesive structure wrapping the first base material.

6. A display module comprising: The flexible circuit board further comprises:

7. A display device comprising: a third cover film between the second signal trace and the second shielding layer. The flexible circuit board further comprises: a second design potential trace and a fourth signal trace stacked between the second signal trace and the second shielding layer in a direction away from the second signal trace; a projection of the second signal trace on the second design potential trace does not exceed a range of the second design potential trace. A display panel and the flexible circuit board as claimed in any one of claims 1-5. A display module as claimed in claim 6.

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