Flexible signal transmission structure

Abstract

The invention discloses a flexible signal transmission structure. The flexible signal transmission structure comprises a substrate and a micro-coaxial transmission structure, and the micro-coaxial transmission structure comprises an outer conductor, a supporting body and an inner conductor. According to the invention, the substrate is provided with the plurality of first stress release grooves, and the orthographic projection of the outer conductor of the micro-coaxial transmission structure on the substrate is set to be partially overlapped with the orthographic projection of the plurality of first stress release grooves on the substrate, so that the arrangement position of the outer conductor corresponds to the arrangement position of the plurality of first stress release grooves. And meanwhile, a second stress release groove is formed in the outer conductor of the micro-coaxial transmission structure, and the consistency of the distribution directions of the second stress release groove and the micro-coaxial transmission structure is ensured, so that a multi-layer and synergistic stress dispersion system is constructed. By means of the design, when the substrate and the micro coaxial transmission structure bear external deformation, stress can be synchronously and effectively absorbed and dispersed, the durability and reliability of the flexible signal transmission structure are improved, and the stability and integrity of the flexible signal transmission structure in high-frequency signal transmission are guaranteed.

Description

Technical Field

[0001] This application belongs to the field of microelectronics technology, specifically relating to a flexible signal transmission structure. Background Technology

[0002] Currently, the fabrication of micro-coaxial transmission structures generally employs silicon-based or glass-based MEMS (Micro-Electro-Mechanical System) processes, forming metal layer structures through copper electroplating or multi-wafer bonding technology. While these structures exhibit excellent performance in high-frequency signal transmission, the inherent high rigidity and brittleness of their substrate materials make it difficult to effectively disperse external stress during dynamic bending.

[0003] When devices employing microcoaxial transmission structures undergo repeated bending or twisting, stress concentration can easily occur in localized areas of the microcoaxial transmission structure's substrate. This can lead to fatigue fracture of the metal conductors (outer and inner conductors) and delamination between different functional layers. This problem not only compromises the stability and integrity of signal transmission but also significantly shortens the lifespan of the microcoaxial transmission structure. Especially in applications requiring frequent deformation, such as wearable devices and flexible displays, the reliability of traditional microcoaxial transmission structures faces severe challenges, making it difficult to meet the high durability and stable signal transmission requirements of modern flexible electronic devices. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a flexible signal transmission structure that can effectively disperse external stress, reduce stress concentration, and prevent fatigue fracture and interface peeling of the micro-coaxial transmission structure, thereby improving the stability and service life of the signal transmission of the flexible signal transmission structure.

[0005] The technical solution adopted to achieve the purpose of this application is as follows: This application provides a flexible signal transmission structure, including: The substrate has a plurality of first stress relief grooves on at least one side along the thickness direction of the substrate; A micro coaxial transmission structure includes an outer conductor, a support body, and an inner conductor. The outer conductor is disposed on one side of the substrate, and the support body and the inner conductor are located inside the outer conductor. The support body is connected to the outer conductor, and the inner conductor is connected to the support body. Wherein, along the thickness direction of the substrate, the orthographic projection of the outer conductor on the substrate partially overlaps with the orthographic projection of the plurality of first stress relief grooves on the substrate; the outer conductor is provided with a plurality of second stress relief grooves, and the distribution direction of the plurality of second stress relief grooves is consistent with the distribution direction of the plurality of first stress relief grooves.

[0006] In some embodiments, the second stress relief groove extends through the outer conductor along the thickness direction of the substrate, and the second stress relief groove extends through one of the sidewalls of the outer conductor distributed along the width direction.

[0007] In some embodiments, a plurality of second stress relief grooves are spaced apart along the length of the outer conductor, and two adjacent second stress relief grooves penetrate different sidewalls of the outer conductor distributed along the width direction.

[0008] In some embodiments, the outer conductor and the plurality of first stress relief grooves are located on the same side of the substrate, and the plurality of second stress relief grooves are correspondingly arranged with the plurality of first stress relief grooves; and / or, The extension direction of the second stress relief groove is the same as that of the first stress relief groove.

[0009] In some embodiments, the ratio of the depth of the first stress relief groove to the thickness of the substrate is greater than or equal to 1 / 3 and less than or equal to 2 / 3; and / or; The distance between two adjacent first stress relief grooves is greater than or equal to 50 μm and less than or equal to 200 μm.

[0010] In some embodiments, the support extends along the width direction of the outer conductor and connects to both sides of the outer conductor along the width direction. The support is provided with a plurality of third stress relief grooves, which penetrate the support along the thickness direction of the substrate and penetrate one side of the support distributed along the length direction of the outer conductor.

[0011] In some embodiments, a plurality of the third stress relief grooves are spaced apart along the width direction of the outer conductor, and two adjacent third stress relief grooves respectively penetrate different sides of the support body distributed along the length direction of the outer conductor.

[0012] In some embodiments, the inner conductor extends along the length direction of the outer conductor, and the inner conductor is provided with a plurality of fourth stress relief grooves, the fourth stress relief grooves penetrating the inner conductor along the thickness direction of the substrate, and the fourth stress relief grooves penetrating one side of the inner conductor along the width direction of the outer conductor; or, The inner conductor extends in a spiral along the length of the outer conductor.

[0013] In some embodiments, a plurality of the fourth stress relief grooves are spaced apart along the length of the outer conductor, and two adjacent fourth stress relief grooves respectively penetrate different sides of the inner conductor distributed along the width of the outer conductor.

[0014] In some embodiments, a plurality of first stress relief grooves are provided on opposite sides of the substrate, and the extension direction and distribution direction of the plurality of first stress relief grooves on opposite sides of the substrate are consistent; along the thickness direction of the substrate, the plurality of first stress relief grooves on opposite sides of the substrate are staggered.

[0015] As can be seen from the above technical solution, this application constructs a multi-layered, synergistic stress dispersion system by setting multiple first stress relief grooves on the substrate and setting the orthographic projection of the outer conductor of the micro-coaxial transmission structure on the substrate to partially overlap with the orthographic projection of the multiple first stress relief grooves on the substrate, so that the outer conductor and the multiple first stress relief grooves are positioned correspondingly. Simultaneously, a second stress relief groove is set on the outer conductor of the micro-coaxial transmission structure, ensuring the consistency of their distribution directions. This design enables the substrate and the micro-coaxial transmission structure to synchronously and effectively absorb and disperse stress when subjected to external deformation, not only improving the durability and reliability of the flexible signal transmission structure but also ensuring its stability and integrity in high-frequency signal transmission. Attached Figure Description

[0016] Figure 1 A schematic diagram of a flexible signal transmission structure from a first perspective provided in an embodiment of this application; Figure 2 A schematic diagram of a flexible signal transmission structure from a second perspective provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of an outer conductor provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an inner conductor provided in an embodiment of this application; Figure 5 This is a schematic diagram of a support structure provided in an embodiment of this application.

[0017] Explanation of reference numerals in the attached figures: 1- Flexible signal transmission structure; 11-Base; 111-First stress relief groove; 12-Micro coaxial transmission structure; 121-Outer conductor; 1211-Second stress relief groove; 122-Support body; 1221-Third stress relief groove; 123-Inner conductor; 1231-Fourth stress relief groove. Detailed Implementation

[0018] To enable those skilled in the art to better understand this application, the technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] In traditional signal transmission structures, due to the inherent high rigidity and brittleness of the substrate material, external stress is difficult to effectively disperse during dynamic bending, leading to stress concentration in localized areas. This stress concentration can easily cause fatigue fracture of the metal conductors in the micro-coaxial transmission structure and interface delamination between different functional layers, thereby compromising the stability and integrity of signal transmission and significantly shortening the service life of the signal transmission structure.

[0020] For example, in the application of flexible displays in wearable smart bracelets, when users perform daily activities that cause the display to bend repeatedly, the substrate of the traditional structure will develop microcracks due to stress concentration, which will cause signal transmission path interruption or image distortion, affecting the reliable operation of the device in dynamic usage environments.

[0021] To address the aforementioned issues, this application provides a flexible signal transmission structure. Please refer to [link / reference]. Figure 1 and Figure 2 The flexible signal transmission structure 1 includes a substrate 11, which serves as the basic load-bearing layer for supporting and protecting other functional layers integrated thereon. Along the thickness direction of the substrate 11, at least one side of the substrate 11 is provided with a plurality of first stress relief grooves 111, the purpose of which is to enhance the flexibility of the substrate 11 and disperse the stress it bears during deformation.

[0022] The first stress relief groove 111 can have a square, trapezoidal, U-shaped, V-shaped, or arc-shaped cross-section along the thickness direction of the substrate 11. This can be achieved through mechanical etching or laser cutting, or fabricated using molding or imprinting techniques. It should be noted that an array of holes distributed along the surface of the substrate 11 can also be formed as the first stress relief groove 111 using photolithography and wet etching processes. By optimizing the cross-sectional shape of the first stress relief groove 111 to be square, trapezoidal, U-shaped, V-shaped, or arc-shaped, the stress distribution of the flexible signal transmission structure 1 can be precisely controlled according to the characteristics of the substrate 11 material, the expected bending mode, and the limitations of the manufacturing process.

[0023] For example, when using a U-shaped or arc-shaped cross-section, the smooth transition area can distribute stress more evenly over a larger volume, effectively avoiding stress concentration and thus significantly reducing local stress peaks when the structure bends. Trapezoidal or V-shaped cross-sections can achieve a good balance between structural stability and flexibility under specific materials or manufacturing processes. Through this precise design of the cross-sectional shape, it can be ensured that when the substrate 11 deforms, the stress can be effectively released along a predetermined path, rather than concentrated at a certain point, thereby significantly improving the fatigue resistance and service life of the entire flexible signal transmission structure 1. This design allows the substrate 11 to deform in a more controlled and uniform manner when subjected to external bending or tensile stress, thereby greatly improving the overall flexibility of the structure without sacrificing signal transmission integrity.

[0024] The flexible signal transmission structure 1 also includes a micro-coaxial transmission structure 12, which includes an outer conductor 121, a support 122, and an inner conductor 123. The support 122 and the inner conductor 123 are located inside the outer conductor 121. The support 122 is connected to the outer conductor 121, and the inner conductor 123 is connected to the support 122. The outer conductor 121 is the outermost conductive part of the micro-coaxial transmission structure 12, typically tubular or slotted, used to shield internal signals and provide a return path. The support 122 is a dielectric material layer in the micro-coaxial transmission structure 12 used to support the inner conductor 123 and isolate it from the outer conductor 121. Its purpose is to ensure that an appropriate distance is maintained between the inner conductor 123 and the outer conductor 121 to maintain the characteristic impedance of the transmission line. The inner conductor 123 is the core conductive part in the micro-coaxial transmission structure 12 used for signal transmission.

[0025] In this configuration, along the thickness direction of the substrate 11, the orthographic projection of the outer conductor 121 onto the substrate 11 partially overlaps with the orthographic projection of the plurality of first stress relief grooves 111 onto the substrate 11. That is, the location of the micro-coaxial transmission structure 12 corresponds to the location of the first stress relief grooves 111. This correspondence ensures that the micro-coaxial transmission structure 12 also receives corresponding stress buffering when the substrate 11 deforms. For example, the micro-coaxial transmission structure 12 can be directly fixed to the surface of the substrate 11 using an adhesive layer, positioned above the first stress relief grooves 111. Alternatively, the micro-coaxial transmission structure 12 can be directly grown on the surface of the substrate 11 using a deposition process, with it staggered with the first stress relief grooves 111 on the same plane. Furthermore, the micro-coaxial transmission structure 12 can be partially or completely embedded into the substrate 11, creating a spatial correspondence with the first stress relief grooves 111.

[0026] Furthermore, the outer conductor 121 is provided with multiple second stress relief grooves 1211, the purpose of which is to enhance the flexibility and stress dispersion capability of the micro-coaxial transmission structure 12 itself. Simultaneously, the distribution direction of the multiple second stress relief grooves 1211 is consistent with the distribution direction of the multiple first stress relief grooves 111, ensuring that the substrate 11 and the micro-coaxial transmission structure 12 can work together to disperse stress during deformation. This consistency in distribution direction allows the substrate 11 and the micro-coaxial transmission structure 12 to release stress synchronously when the entire flexible signal transmission structure 1 bends, thereby effectively protecting the internal signal transmission path.

[0027] This embodiment of the application constructs a multi-layered, synergistic stress dispersion system by setting multiple first stress relief grooves 111 on the substrate 11 and setting the orthographic projection of the outer conductor 121 of the micro-coaxial transmission structure 12 on the substrate 11 to partially overlap with the orthographic projections of the multiple first stress relief grooves 111 on the substrate 11, so that the outer conductor 121 and the multiple first stress relief grooves 111 are positioned correspondingly. At the same time, a second stress relief groove 1211 is set on the outer conductor 121 of the micro-coaxial transmission structure 12, and the distribution direction of both is kept consistent. This design enables the substrate 11 and the micro-coaxial transmission structure 12 to absorb and disperse stress synchronously and effectively when subjected to external deformation, which not only improves the durability and reliability of the flexible signal transmission structure 1, but also ensures its stability and integrity in high-frequency signal transmission, thereby meeting the stringent requirements of flexible electronic devices for high durability and stable signal transmission.

[0028] In some embodiments, please refer to Figure 3 The second stress relief groove 1211 penetrates the outer conductor 121 along the thickness direction of the base 11. That is, the second stress relief groove 1211 completely penetrates the entire height of the outer conductor 121 in a direction perpendicular to the plane of the base 11. This through-through design can effectively increase the local flexibility of the outer conductor 121, allowing the outer conductor 121 to deform better when bent, avoiding stress concentration. At the same time, the second stress relief groove 1211 penetrates one of the sidewalls of the outer conductor 121 distributed along the width direction. That is, the second stress relief groove 1211 also extends from one of the sidewalls in the width direction of the outer conductor 121 and forms an opening. This design further enhances the flexibility of the outer conductor 121, especially when bending in a specific direction is required, it can provide greater deformation space and reduce stress.

[0029] This embodiment of the application provides a second stress relief groove 1211 on the outer conductor 121 of the micro-coaxial transmission structure 12. This groove penetrates the top and bottom of the outer conductor 121 along the thickness direction of the substrate 11, effectively "cutting" the outer conductor 121 vertically, thus greatly increasing its deformation capacity during bending. Furthermore, the second stress relief groove 1211 also penetrates one of the sidewalls of the outer conductor 121 along its width direction. This means that the groove forms an opening in the width direction, further breaking the continuity of the outer conductor 121. This allows stress to be effectively released and dispersed through these openings when the outer conductor 121 is bent, preventing stress concentration in specific areas. This through-hole and lateral opening design allows the outer conductor 121 to deform with less stress during bending, significantly improving the flexibility and reliability of the entire flexible signal transmission structure 1 and effectively solving the problem of structural failure caused by stress concentration during bending of the outer conductor 121.

[0030] In some examples, please refer to Figure 3 Multiple second stress relief grooves 1211 are spaced apart along the length of the outer conductor 121. That is, the multiple second stress relief grooves 1211 are not arranged continuously, but are separated from each other at a certain distance along the length of the outer conductor 121. The purpose of this spacing is to form a series of alternating flexible and rigid regions on the outer conductor 121, thereby effectively dispersing bending stress while ensuring the overall structural strength. The spacing can be implemented in various ways. For example, it can be evenly spaced, meaning the distance between adjacent second stress relief grooves 1211 remains consistent; or it can be non-equally spaced, for example, by densely or sparsely arranging the second stress relief grooves 1211 in specific areas according to the expected bending pattern or stress distribution.

[0031] Simultaneously, two adjacent second stress relief grooves 1211 penetrate different sidewalls of the outer conductor 121 along its width direction. That is, the sidewalls penetrated by two adjacent second stress relief grooves 1211 are different along the width direction of the outer conductor 121. This alternating penetration of different sidewalls aims to avoid forming a continuous, penetrating weakened region on one side of the outer conductor 121. In this way, bending stress can be effectively distributed to both sides of the outer conductor 121, thereby providing stress relief in multiple directions, enhancing the overall flexibility of the structure, and improving its fatigue resistance under multi-directional bending or torsional conditions.

[0032] This embodiment optimizes the stress relief mechanism of the outer conductor 121 of the micro-coaxial transmission structure 12 by arranging multiple second stress relief grooves 1211 at intervals along the length of the outer conductor 121 and ensuring that adjacent second stress relief grooves 1211 penetrate different sidewalls of the outer conductor 121 distributed along its width. When the flexible signal transmission structure 1 is bent or deformed, these spaced second stress relief grooves 1211 can disperse the bending stress to multiple discrete regions of the outer conductor 121, avoiding excessive stress concentration in a single continuous region. Simultaneously, because adjacent second stress relief grooves 1211 alternately penetrate different sidewalls of the outer conductor 121, the outer conductor 121 does not form a single, continuous weak line along its width. Instead, the stress is guided to both sides of the outer conductor 121, forming a zigzag or staggered stress path, thereby distributing stress more evenly when the outer conductor 121 bends, effectively reducing local stress peaks. This design not only enhances the bending flexibility of the outer conductor 121 in a single direction, but also enables it to better adapt to bending and twisting in multiple directions, significantly improving the reliability and service life of the micro-coaxial transmission structure 12 in dynamic applications. Compared with a scheme that sets stress relief grooves only on the same sidewall, this structure, which alternately runs through different sidewalls, avoids structural failure caused by continuous weakening, allowing the entire flexible signal transmission structure 1 to maintain signal integrity while possessing superior mechanical flexibility.

[0033] In some embodiments, please refer to Figure 1 The outer conductor 121 and multiple first stress relief grooves 111 are located on the same side of the substrate 11. Multiple second stress relief grooves 1211 are correspondingly arranged with the multiple first stress relief grooves 111, meaning that the second stress relief grooves 1211 have a one-to-one spatial correspondence or geometric relationship with the first stress relief grooves 111. This correspondence ensures that when the structure is under stress, the stress can be effectively transmitted and released along a preset path, avoiding stress concentration. At the same time, the corresponding arrangement of the second stress relief grooves 1211 and the first stress relief grooves 111 also ensures that there is sufficient connection area between the outer conductor 121 and the substrate 11, thereby ensuring the connection strength and connection stability between the micro-coaxial transmission structure 12 and the substrate 11.

[0034] The extension direction of the second stress relief groove 1211 is consistent with the extension direction of the first stress relief groove 111. That is, the main length directions of the first stress relief groove 111 and the second stress relief groove 1211 in their respective planes are the same. This ensures that when the structure deforms, the stress relief grooves can deform along the same direction, thereby working together to disperse and absorb stress.

[0035] This embodiment of the application arranges multiple second stress relief grooves 1211 in the flexible signal transmission structure 1 corresponding to multiple first stress relief grooves 111, and ensures that the extension direction of the second stress relief grooves 1211 is consistent with the extension direction of the first stress relief grooves 111. This allows the substrate 11 and the micro-coaxial transmission structure 12 to achieve more coordinated and synchronous stress relief when the flexible signal transmission structure 1 is subjected to external stress. Specifically, when the structure bends or deforms, because the first stress relief grooves 111 and the second stress relief grooves 1211 are precisely corresponding in space and have the same extension direction, they can work together to form a continuous and efficient stress dispersion path. This precise alignment and directional consistency in the structure allows stress to be effectively transferred from the substrate 11 to the outer conductor 121 and evenly dispersed along the preset stress relief grooves, avoiding stress concentration in specific areas. This not only enhances the overall flexibility and fatigue resistance of the flexible signal transmission structure 1, but also ensures that the support 122 and inner conductor 123 inside the micro-coaxial transmission structure 12 maintain a relatively stable geometric relationship during deformation, thereby effectively maintaining the impedance matching and transmission performance of the signal transmission.

[0036] In some examples, the width of the first stress relief groove 111 is less than or equal to the width of the second stress relief groove 1211. By defining the width relationship between the first stress relief groove 111 and the second stress relief groove 1211, the stress distribution of the flexible signal transmission structure 1 under stress is optimized. When the flexible signal transmission structure 1 is subjected to bending or deformation, stress is generated in both the substrate 11 and the micro-coaxial transmission structure 12. The first stress relief groove 111 and the second stress relief groove 1211 work together to absorb and disperse these stresses. By ensuring that the width of the first stress relief groove 111 is less than or equal to the width of the second stress relief groove 1211, precise control of stress transmission between the substrate 11 and the outer conductor 121 can be achieved.

[0037] If the width of the first stress relief groove 111 is smaller than the width of the second stress relief groove 1211, the substrate 11 can provide stronger local support for the micro-coaxial transmission structure 12 in the stress relief groove region, ensuring the connection stability between the micro-coaxial transmission structure 12 and the substrate 11. If the widths of the two are equal, the consistency of the stress relief mechanism between the substrate 11 and the outer conductor 121 is ensured, allowing them to deform more synchronously. This avoids structural delamination or premature failure that may be caused by interlayer stress mismatch. This coordinated stress management mechanism significantly enhances the flexibility and mechanical stability of the entire structure.

[0038] In some examples, the ratio of the depth of the first stress relief groove 111 to the thickness of the substrate 11 is greater than or equal to 1 / 3 and less than or equal to 2 / 3. By controlling this ratio, the bending stiffness in local areas can be effectively reduced while ensuring the overall structural strength of the substrate 11, thereby improving the flexibility of the structure. For example, this depth can be achieved through precisely controlled processes such as laser ablation, chemical etching, or mechanical milling, where process parameters (such as laser energy, etching time, or milling depth) can be adjusted according to the material properties and thickness of the substrate 11.

[0039] In the actual manufacturing process, the ratio of the depth of the first stress relief groove 111 to the thickness of the base 11 can be set to 1 / 3, 1 / 2 or 2 / 3, etc. The specific ratio can be selected and adjusted according to the actual design requirements, and no special limitation is made here.

[0040] In some examples, the spacing between two adjacent first stress relief grooves 111 is greater than or equal to 50 μm and less than or equal to 200 μm. This spacing defines the distribution density of the first stress relief grooves 111 on the substrate 11, ensuring a uniform distribution of the first stress relief grooves 111 on the substrate 11. This allows the entire substrate 11 to achieve smoother and more uniform deformation during bending, avoiding local stress concentration and preventing a significant decrease in the strength of the substrate 11 due to excessively small groove spacing. This spacing can be precisely controlled through photolithography mask design, CNC machining path planning, or precision mold forming to meet specific flexibility requirements.

[0041] In the actual manufacturing process, the spacing between two adjacent first stress relief grooves 111 can be set to 50μm, 100μm, 150μm or 200μm, etc. The specific spacing value can be selected and adjusted according to the actual design requirements, and no special limitation is made here.

[0042] In some examples, the ratio of the depth of the first stress relief groove 111 to the thickness of the substrate 11 and the spacing between two adjacent first stress relief grooves 111 can be designed simultaneously. Specifically, the ratio of the depth of the first stress relief groove 111 to the thickness of the substrate 11 can be set to be greater than or equal to 1 / 3 and less than or equal to 2 / 3, while the spacing between two adjacent first stress relief grooves 111 can be set to be greater than or equal to 50 μm and less than or equal to 200 μm. This optimized combination of depth and spacing allows the substrate 11 to maintain sufficient mechanical strength while achieving excellent flexibility. This enables the entire flexible signal transmission structure 1 to effectively resist fatigue damage during repeated bending or twisting, ensuring the stability and reliability of signal transmission.

[0043] In some embodiments, please refer to Figure 5The support body 122 extends along the width direction of the outer conductor 121 and connects to both sides of the outer conductor 121 along the width direction. That is, the support body 122 plays a lateral supporting role in the micro-coaxial transmission structure 12, ensuring the stable position of the inner conductor 123 within the transmission structure. The support body 122 is provided with multiple third stress relief grooves 1221. The purpose of the third stress relief grooves 1221 is to reduce the local stiffness of the support body 122 under stress by introducing structural discontinuities, thereby improving its flexibility. These third stress relief grooves 1221 can be formed by processes such as laser cutting, chemical etching, or mechanical milling.

[0044] The third stress relief groove 1221 penetrates the support 122 along the thickness direction of the base 11, and also penetrates one side of the support 122 distributed along the length direction of the outer conductor 121. That is, the third stress relief groove 1221 completely penetrates the thickness of the support 122, thereby maximally reducing the rigidity of the support 122 in the bending direction. Simultaneously, the penetration of the third stress relief groove 1221 through one side of the support 122 distributed along the length direction of the outer conductor 121 further enhances the flexibility of the support 122 and may facilitate the formation of these grooves during manufacturing. This side penetration can be achieved by the groove opening being completely open on one long side of the support 122, or by introducing it from the side during manufacturing using a mold or cutting tool.

[0045] This embodiment of the application provides multiple third stress relief grooves 1221 on the support body 122, enabling the support body 122 to effectively reduce its local rigidity while maintaining its supporting function for the inner conductor 123. When the flexible signal transmission structure 1 bends or deforms, these third stress relief grooves 1221, which penetrate the top and bottom surfaces of the support body 122 and extend to one of its sides, provide additional deformation space, allowing the support body 122 to bend more smoothly along with the outer conductor 121 and the substrate 11, thereby preventing excessive stress concentration inside the support body 122 or at its connection with the outer conductor 121. This design, together with the first stress relief groove 111 on the substrate 11 and the second stress relief groove 1211 on the outer conductor 121, forms a multi-layered, multi-dimensional stress relief mechanism. The stress relief grooves on the substrate 11 and the outer conductor 121 mainly address the bending stress at the macroscopic level, while the third stress relief groove 1221 on the support 122 further addresses the local stress problem inside the micro-coaxial transmission structure 12, ensuring the coordinated deformation of each component of the entire flexible signal transmission structure 1 under bending conditions, thereby maintaining the stability of signal transmission and the integrity of the structure.

[0046] In some examples, multiple third stress relief grooves 1221 are spaced apart along the width direction of the outer conductor 121, and adjacent third stress relief grooves 1221 penetrate different sides of the support 122 distributed along the length direction of the outer conductor 121. That is, the third stress relief grooves 1221 on the support 122 are not arranged continuously along the width direction of the outer conductor 121, but are distributed at certain intervals. This spacing can effectively disperse stress and avoid stress concentration in a single area, thereby improving the overall flexibility and fatigue resistance of the structure. For example, these stress relief grooves can be evenly spaced or non-uniformly spaced according to the expected bending pattern to adapt to different stress distribution requirements. At the same time, the sides of the support 122 penetrated by two adjacent third stress relief grooves 1221 in the width direction are alternate. This alternating penetration design forms a "zigzag" or "wavy" stress relief path, which can more effectively guide and disperse the stress generated during bending or torsion, further enhancing the flexibility of the structure and preventing structural failure due to unidirectional stress concentration.

[0047] This embodiment of the application forms a unique stress dispersion mechanism by arranging multiple third stress relief grooves 1221 at intervals along the width direction of the outer conductor 121 on the support body 122, with adjacent third stress relief grooves 1221 penetrating different sides of the support body 122 along the length direction of the outer conductor 121. When the flexible signal transmission structure 1 is subjected to bending or torsional stress, these interlaced third stress relief grooves 1221 can effectively guide the stress to different paths, avoiding excessive stress concentration in a single direction or on a single side. This design allows the support body 122 to undergo local deformation and stress release through these alternating openings when subjected to deformation, thereby significantly improving the flexibility and fatigue resistance of the entire micro-coaxial transmission structure 12, and even the entire flexible signal transmission structure 1. This structural layout effectively disperses stress over a wider area, reduces local stress peaks, thereby extending the service life of the structure and ensuring signal transmission stability under dynamic bending conditions.

[0048] In some embodiments, please refer to Figure 4The inner conductor 123 extends along the length of the outer conductor 121. As the core conductive part for signal transmission, the inner conductor 123's main structure is arranged along the main axis of the micro-coaxial transmission structure 12. This extension method ensures the continuity of signal transmission and the stability of the path. The inner conductor 123 can be made of various conductive materials, such as metals like copper, silver, and gold, or conductive polymers. Multiple fourth stress relief grooves 1231 are provided on the inner conductor 123 to disperse or alleviate stress concentration when the inner conductor 123 is subjected to external mechanical stress (such as bending or torsion), thereby improving the flexibility and fatigue resistance of the inner conductor 123. The shape of the fourth stress relief grooves 1231 can be varied, such as rectangular, circular, elliptical, U-shaped, or V-shaped.

[0049] The fourth stress relief groove 1231 extends through the inner conductor 123 along the thickness direction of the substrate 11, and also penetrates one side of the inner conductor 123 along the width direction of the outer conductor 121. That is, the fourth stress relief groove 1231 extends from the upper surface to the lower surface of the inner conductor 123, forming a completely continuous structure. This through-hole design ensures that the fourth stress relief groove 1231 functions throughout the entire thickness direction of the inner conductor 123, thereby minimizing the internal stress generated when the inner conductor 123 is bent or twisted. Simultaneously, the fourth stress relief groove 1231 extends and passes through one side of the inner conductor 123 along the width direction of the outer conductor 121. This design further enhances the flexibility of the inner conductor 123, especially when bending or twisting along the width direction is required, effectively alleviating lateral stress and preventing damage to the inner conductor 123 due to excessive local stress.

[0050] This embodiment optimizes the structure of the inner conductor 123 to better adapt to the deformation of the flexible signal transmission structure 1 during bending and torsion. When the inner conductor 123 is provided with multiple fourth stress relief grooves 1231, these grooves form multiple deformable micro-units inside the inner conductor 123. When the entire flexible signal transmission structure 1 bends or torsional, these micro-units can deform relatively independently, thereby dispersing the stress originally concentrated in a certain area of ​​the inner conductor 123 to the edges and walls of the multiple fourth stress relief grooves 1231. The fourth stress relief grooves 1231 penetrate the top and bottom surfaces of the inner conductor 123 along the thickness direction of the substrate 11, and also penetrate one side of the inner conductor 123 along the width direction of the outer conductor 121. This three-dimensional through-hole design enables the inner conductor 123 to have stress relief capabilities in multiple directions, effectively preventing the inner conductor 123 from becoming a weak point in the entire structure due to excessive rigidity, thereby ensuring the continuity and stability of signal transmission.

[0051] In some examples, multiple fourth stress-relieving grooves 1231 are spaced apart along the length of the outer conductor 121, with adjacent fourth stress-relieving grooves 1231 penetrating different sides of the inner conductor 123 distributed along the width of the outer conductor 121. That is, in the longitudinal extension direction of the inner conductor 123, these stress-relieving groove structures are distributed at a certain interval, rather than being continuous or closely arranged; simultaneously, in the width direction of the inner conductor 123, the opening positions of adjacent fourth stress-relieving grooves 1231 are alternating. This spacing can be achieved in various ways, such as by periodically laser etching, chemical etching, or micromachining on the inner conductor 123 to form a series of discrete grooves. This distribution helps to maintain the overall mechanical strength of the inner conductor 123 and the continuity of signal transmission while providing flexibility.

[0052] This embodiment of the application provides a unique stress relief mechanism by providing multiple fourth stress relief grooves 1231 on the inner conductor 123 of the flexible signal transmission structure 1. These grooves are spaced apart along the length of the outer conductor 121, and adjacent fourth stress relief grooves 1231 penetrate different sides of the inner conductor 123 distributed along the width of the outer conductor 121. When the flexible signal transmission structure 1 bends in different directions, the tensile and compressive stresses borne by the inner conductor 123 can be distributed more evenly and effectively. For example, when the structure bends to one side, the fourth stress relief grooves 1231 on that side can effectively open and release stress; when the structure bends to the other side, the fourth stress relief grooves 1231 on the other side take effect. This alternating penetration design ensures that the inner conductor 123 receives sufficient stress relief in any bending direction, avoiding fatigue and damage caused by stress concentration in one direction. This, together with the first stress relief groove 111 on the substrate 11 and the second stress relief groove 1211 on the outer conductor 121, further enhances the reliability and durability of the entire flexible signal transmission structure 1 under complex bending conditions, ensuring the stability and integrity of signal transmission.

[0053] In some examples, the inner conductor 123 extends spirally along the length of the outer conductor 121. That is, the inner conductor 123 no longer extends in a straight line along the length of the outer conductor 121, but is arranged in a spiral path. The spiral structure itself has spring-like properties. When the flexible signal transmission structure 1 is subjected to bending, torsional, or tensile stress, the spiral inner conductor 123 can absorb these mechanical stresses through its own tensile, compressive, or torsional deformation. This deformation is uniform and reversible, avoiding excessive local strain in the inner conductor 123 material itself, thereby effectively preventing fatigue damage or fracture of the inner conductor 123. The spirally extending inner conductor 123 can be achieved by spirally depositing conductive material on the support 122, or by embedding or bonding prefabricated spiral wires inside the support 122.

[0054] In some embodiments, please refer to Figure 1 Multiple first stress relief grooves 111 are provided on opposite sides of the base 11, that is, first stress relief grooves 111 are provided on two opposite surfaces of the base 11, such as the top and bottom surfaces. This double-sided arrangement aims to more comprehensively disperse and absorb the stress of the base 11 under stress, thereby improving the flexibility and fatigue resistance of the overall structure.

[0055] In this design, the extension and distribution directions of the multiple first stress relief grooves 111 on opposite sides of the base 11 are consistent; that is, the geometric arrangement of the first stress relief grooves 111 at the top and bottom of the base 11 is the same. For example, if the grooves at the top are arranged laterally, the grooves at the bottom are also arranged laterally; if the grooves at the top extend along the length direction, the grooves at the bottom also extend along the length direction. Maintaining directional consistency helps the stress relief grooves on both sides deform in a similar manner when the structure bends, thereby providing a uniform stress relief effect and avoiding local stress concentration caused by inconsistent directions.

[0056] Meanwhile, along the thickness direction of the base 11, multiple first stress relief grooves 111 on opposite sides of the base 11 are staggered. "Staggered arrangement" means that when viewed from the thickness direction of the base 11, the positions of the top and bottom stress relief grooves do not overlap in the planar projection, but are offset from each other. This staggered arrangement avoids the formation of continuous weak areas in the thickness direction of the base 11, thereby improving flexibility while maintaining the overall structural strength and stability of the base 11. It helps to more effectively disperse stress and prevent stress concentration on the same vertical cross-section.

[0057] This embodiment of the application forms a unique stress management mechanism by providing multiple first stress relief grooves 111 on opposite sides of the substrate 11, with the extension and distribution directions of these grooves being consistent, and the grooves on both sides being staggered along the thickness direction of the substrate 11. When the flexible signal transmission structure 1 is subjected to external stresses such as bending or torsion, the first stress relief grooves 111 on both sides of the substrate 11 can work together to absorb and disperse the stress. Since the first stress relief grooves 111 are provided on both sides and are oriented in the same direction, the flexibility of the substrate 11 is evenly improved in different directions. More importantly, the staggered arrangement of the first stress relief grooves 111 on both sides avoids the formation of a through stress concentration area in the thickness direction of the substrate 11, thereby effectively releasing stress while maintaining the structural integrity and load-bearing capacity of the substrate 11. This design allows the substrate 11 to maintain high flexibility while avoiding fatigue damage caused by excessive stress concentration, thereby improving the reliability and service life of the flexible signal transmission structure 1.

[0058] It should be noted that the choice of substrate 11 material is crucial to the overall flexibility, mechanical strength, durability and signal transmission performance of the structure. In the embodiments of this application, the substrate 11 material includes polyimide, polyethylene terephthalate, polyimide-graphene composite material or polydimethylsiloxane-carbon nanotube composite material.

[0059] Polyimide is a high-performance polymer known for its excellent high-temperature resistance, mechanical strength, chemical stability and good flexibility, and is widely used in the field of flexible electronics. Its molecular structure makes it less prone to permanent deformation when bent and stretched, and can effectively resist fatigue damage.

[0060] Polyethylene terephthalate (PET) is a thermoplastic polyester with good mechanical properties, dimensional stability, and cost-effectiveness. It offers moderate flexibility and is easy to process, making it suitable for applications where flexibility is required but cost is a concern.

[0061] Polyimide-graphene composites combine the excellent properties of polyimide with the ultra-high strength, electrical conductivity, and thermal conductivity of graphene. By introducing graphene into the polyimide matrix, the mechanical strength, fatigue resistance, and thermal management capabilities of the substrate can be significantly improved, while maintaining or even enhancing its flexibility, which is particularly advantageous for high-frequency signal transmission and high-density integration.

[0062] Polydimethylsiloxane-carbon nanotube composites utilize the inherent high elasticity, biocompatibility, and excellent flexibility of polydimethylsiloxane, combined with the superior mechanical strength and conductivity of carbon nanotubes. This composite material offers extremely high tensile and bending properties, making it suitable for applications requiring extreme flexibility, such as wearable devices or biomedical sensors.

[0063] This application embodiment selects a specific substrate 11 material for the flexible signal transmission structure 1, enabling the substrate 11 to possess excellent flexibility, mechanical strength, and fatigue resistance. When the substrate 11 is made of polyimide, polyethylene terephthalate, polyimide-graphene composite material, or polydimethylsiloxane-carbon nanotube composite material, the inherent high elastic modulus, good elongation at break, and excellent elastic recovery of these materials allow the substrate 11 to effectively absorb and disperse mechanical stresses such as bending and tension, preventing microcracks or plastic deformation within the material. Furthermore, the multiple first stress relief grooves 111 provided on the substrate 11 further guide and disperse stress concentration, creating a synergistic effect with the inherent flexibility of the substrate 11 material. This combination of structure and material allows the entire flexible signal transmission structure 1 to maintain its structural integrity and signal transmission stability even under repeated bending or long-term deformation, effectively solving the reliability problem caused by material fatigue.

[0064] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0065] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A flexible signal transmission structure, characterized by, The application relates to a coaxial transmission structure, comprising: a substrate, at least one side of the substrate being provided with a plurality of first stress release grooves in the thickness direction of the substrate; a micro coaxial transmission structure, comprising an outer conductor, a support body and an inner conductor, the outer conductor being arranged on one side of the substrate, the support body and the inner conductor being arranged in the outer conductor, the support body being connected with the outer conductor, and the inner conductor being connected with the support body; wherein the orthographic projection of the outer conductor on the substrate partially overlaps with the orthographic projection of the plurality of first stress release grooves on the substrate in the thickness direction of the substrate; the outer conductor is provided with a plurality of second stress release grooves, and the distribution direction of the plurality of second stress release grooves is consistent with the distribution direction of the plurality of first stress release grooves.

2. The flexible signal transmission structure of claim 1, wherein, The second stress release grooves penetrate the outer conductor in the thickness direction of the substrate, and the second stress release grooves penetrate one of the side walls of the outer conductor distributed in the width direction.

3. The flexible signal transmission structure of claim 2, wherein, The plurality of second stress release grooves are arranged at intervals in the length direction of the outer conductor, and adjacent two second stress release grooves penetrate different side walls of the outer conductor distributed in the width direction.

4. The flexible signal transmission structure of claim 1, wherein, The outer conductor and the plurality of first stress release grooves are located on the same side of the substrate, and the plurality of second stress release grooves are arranged correspondingly with the plurality of first stress release grooves; and / or, The extension direction of the second stress release grooves is consistent with the extension direction of the first stress release grooves.

5. The flexible signal transmission structure of claim 1, wherein, The ratio of the depth of the first stress release grooves to the thickness of the substrate is greater than or equal to 1 / 3 and less than or equal to 2 / 3; and / or; The interval of adjacent two first stress release grooves is greater than or equal to 50 mu m and less than or equal to 200 mu m.

6. The flexible signal transmission structure of claim 1, wherein, The support body extends in the width direction of the outer conductor and is connected with both sides of the outer conductor in the width direction, the support body is provided with a plurality of third stress release grooves, the third stress release grooves penetrate the support body in the thickness direction of the substrate, and the third stress release grooves penetrate one of the side faces of the support body distributed in the length direction of the outer conductor.

7. The flexible signal transmission structure of claim 6, wherein, The plurality of third stress release grooves are arranged at intervals in the width direction of the outer conductor, and adjacent two third stress release grooves penetrate different side faces of the support body distributed in the length direction of the outer conductor.

8. The flexible transmission structure of claim 1, wherein, The inner conductor extends in the length direction of the outer conductor, the inner conductor is provided with a plurality of fourth stress release grooves, the fourth stress release grooves penetrate the inner conductor in the thickness direction of the substrate, and the fourth stress release grooves penetrate one of the side faces of the inner conductor distributed in the width direction of the outer conductor; or, The inner conductor extends in the length direction of the outer conductor in a spiral manner.

9. The flexible transmission structure of claim 8, wherein, The plurality of fourth stress release grooves are arranged at intervals in the length direction of the outer conductor, and adjacent two fourth stress release grooves penetrate different side faces of the inner conductor distributed in the width direction of the outer conductor.

10. The flexible signal transmission structure according to any one of claims 1 to 9, characterized in that, The opposite sides of the substrate are respectively provided with a plurality of first stress release grooves, the extension direction and distribution direction of the plurality of first stress release grooves on the opposite sides of the substrate are consistent; and the plurality of first stress release grooves on the opposite sides of the substrate are staggered in the thickness direction of the substrate.

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