PCB board with reduced thermal expansion stress, acceleration sensing system and method

Abstract

This invention discloses a PCB board with reduced thermal expansion stress, an acceleration sensing system, and a method. It includes: a substrate; and a conductive mechanism comprising a conductive body disposed at the top of the substrate. The conductive body has multiple slot channels penetrating its top and bottom ends to divide it into multiple conductive units. When the temperature rises, the multiple conductive units undergo thermal expansion and deformation, causing adjacent conductive units to move closer together within the slot channels, thereby improving the flatness of the upper surface of the conductive body at high temperatures. This application provides stress relief space for the conductive body when the ambient temperature changes, improving the overall flatness of the conductive body and thus enhancing the stability of the transmitted signals of devices electrically connected to the conductive body.

Description

Technical Field

[0001] This invention relates to the field of printed circuit boards, and further to a PCB board with reduced thermal expansion stress, an acceleration sensing system, and a method thereof. Background Technology

[0002] Circuit boards serve as the carriers for electrical connections between electronic components and are widely used in various electronic devices and sensing systems. Their surfaces integrate multiple pads to achieve stable electrical connections between components such as sensors and the circuit board. Various sensors can be electrically connected to the pads, thereby connecting to the circuit board.

[0003] In existing technologies, to ensure a stable connection between the sensor and the PCB board, the size of the pads needs to be designed according to a standard area. However, in high-temperature environments, due to the inconsistency of materials between the PCB substrate, the pads, and the sensor, the coefficients of thermal expansion of the three materials are inconsistent. This causes the connection between the pads and the sensor to be deformed by thermal expansion and squeezed against each other, thereby generating thermal stress. This results in changes to the flatness of the pad surface. As the flatness is altered, the thermal stress is transmitted to the interior of the sensor, thereby reducing the sensor's measurement accuracy. At the same time, during heating and cooling cycles, the rigid pads cannot release the accumulated stress, which will cause further changes in the flatness of the pad surface, leading to inconsistent detection data from the sensor under the same temperature and sensing adjustment. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a PCB board with reduced thermal expansion stress, an acceleration sensing system, and a method. This application provides space for stress release in the conductive body when the ambient temperature changes, improving the overall flatness of the conductive body and thus enhancing the stability of the transmitted signals of devices electrically connected to the conductive body.

[0005] To achieve the above objectives, the present invention aims to provide, in a first aspect, a PCB board with reduced thermal expansion stress, comprising:

[0006] substrate;

[0007] A conductive mechanism includes a conductive body disposed at the top of the substrate. The conductive body has multiple slot channels extending through the top and bottom of the conductive body to divide the conductive body into multiple conductive units.

[0008] When the temperature rises, the multiple conductive units expand and deform due to heat, causing two adjacent conductive units to move closer to each other within the gap channel, thereby improving the flatness of the upper surface of the conductive body at high temperatures.

[0009] In some embodiments, the slit channel includes a plurality of transverse channels, all of which are arranged along the length extension direction of the conductive body. The conductive unit is formed between two adjacent transverse channels, and the inner wall surface of the edge of each transverse channel is at a certain distance from the outer wall surface of the edge of the conductive body.

[0010] In some embodiments, the slot channel includes a plurality of longitudinal channels, all of which are arranged along the width extension direction of the conductive body, and each longitudinal channel is connected to a corresponding transverse channel to divide each conductive unit into a sub-conductive unit;

[0011] The PCB board also includes a conductive connector, which is disposed in the longitudinal channel, and its two ends are respectively connected to two adjacent sub-conductive units.

[0012] In some embodiments, the two ends of the conductive connector are respectively connected to one side edge of two adjacent sub-conductive units, and the middle portion of the conductive connector extends towards the other side edge of the sub-conductive unit with a first protrusion. A first space is formed at the middle position of the first protrusion, and the first space communicates with a transverse channel near one side edge of the sub-conductive unit. A second space and a third space are formed between the first protrusion and the two sub-conductive units, respectively. Both the second space and the third space communicate with the transverse channel near the other side edge of the sub-conductive unit.

[0013] In some embodiments, the PCB board includes a fall arrestor located within the gap channel;

[0014] When the anti-fall device is installed in the gap channel, there is a certain gap between the outer edge of the anti-fall device and the inner edge of the corresponding gap channel.

[0015] In some embodiments, at least one receiving groove is formed at the top of the substrate, and the conductive body is disposed in the receiving groove;

[0016] One end of the anti-fall component is connected to the bottom wall of the receiving groove, and the other end extends within the gap channel.

[0017] The PCB board includes a solder mask layer disposed at the top of the substrate. The solder mask layer has a communicating channel corresponding to the receiving groove, and the size of the communicating channel is greater than or equal to the opening size of the receiving groove in a direction parallel to the top plane of the substrate; or

[0018] The top of the substrate is provided with at least one receiving groove, and the conductive body is disposed in the receiving groove;

[0019] The side of the receiving groove has an arc-shaped deformation groove, which is connected to the receiving groove. When the temperature rises, the conductive body thermally expands and deforms into the arc-shaped deformation groove to improve the flatness of the upper surface of the conductive body at high temperature.

[0020] In some embodiments, arc-shaped grooves are formed on the inner wall surfaces at both ends of the plurality of slit channels, and the arc-shaped grooves are in communication with the slit channels;

[0021] The conductive body includes a first body and a second body. The second body is disposed on the top of the PCB board, and the first body is disposed on the second body. The arc-shaped groove includes a first arc-shaped groove and a second arc-shaped groove that are interconnected. The first arc-shaped groove is located at the end of the first body that is close to the PCB board, and the second arc-shaped groove is located at the end of the second body that is away from the PCB board.

[0022] A plurality of fourth spaces are formed between the first body and the second body, and the fourth spaces are located inside the conductive unit.

[0023] In some embodiments, the slit channel is an annular channel, the annular channel including a first annular channel and a second annular channel arranged concentrically, and the first annular channel and the second annular channel divide the conductive body into three conductive units;

[0024] The conduction mechanism includes multiple conduction connectors, which are located in the first annular channel and the second annular channel respectively and connected to two adjacent conduction units. The multiple conduction connectors in the first annular channel are arranged in a ring around the center line of the first annular channel, and the multiple conduction connectors in the second annular channel are arranged in a ring around the center line of the second annular channel.

[0025] Each of the conductive connectors includes at least a sixth connector and a seventh connector connected in sequence. The conductive connector is generally V-shaped, and the length extension direction of the sixth connector has a preset angle with the length extension direction of the seventh connector.

[0026] A second aspect of the present invention provides an acceleration sensing system, comprising:

[0027] As mentioned above, it features a PCB board that reduces thermal expansion stress;

[0028] An accelerometer is located at the top of the PCB board. The accelerometer includes a sensor body and pins. One end of the pins is electrically connected to the sensor body, and the other end is electrically connected to the conduction mechanism disposed on the substrate.

[0029] A third aspect of the present invention provides a method for manufacturing a circuit board for use in a PCB board as described above, comprising:

[0030] S1: Fix the substrate and the conductive body to preset positions respectively;

[0031] S2: The slit channel is formed on the conductive body by an etching process;

[0032] S3: Connect the conductive body to the top of the substrate.

[0033] In some embodiments, the conductive body includes a first body and a second body, the second body is disposed on the top of the PCB board, the first body is disposed on the second body, and arc-shaped grooves are formed on the inner wall surfaces at both ends of the plurality of gap channels. The arc-shaped grooves include a first arc-shaped groove and a second arc-shaped groove that are interconnected. The first arc-shaped groove is located at the end of the first body that is close to the PCB board, and the second arc-shaped groove is located at the end of the second body that is away from the PCB board.

[0034] The first body is processed, and the slit channel and the first arc-shaped groove are formed in the first body;

[0035] The second body is processed, and the slit channel and the second arc-shaped groove are formed in the second body;

[0036] The first body and the second body are stacked so that the first arc-shaped groove and the second arc-shaped groove are connected to each other to form the arc-shaped groove;

[0037] The first body and the second body are fixedly connected by a bonding process.

[0038] Beneficial effects:

[0039] (1) In this invention, the sensor is suitable for electrical connection with the conductive body. The slot channel is formed on the conductive body and divides the conductive body into multiple conductive units. The slot channel provides space for deformation of multiple conductive units. When the ambient temperature of the PCB board increases, the conductive body is affected by the temperature, causing multiple adjacent conductive units to move closer to each other in the slot channel. At this time, the slot channel provides deformation space for the thermal expansion of multiple conductive units, effectively reducing the stress caused by the thermal expansion of the conductive body, improving the surface flatness of the conductive body, thereby improving the stability of the electrical connection between the sensor and the conductive body, and effectively suppressing the zero-position shift of some sensors. When the ambient temperature of the PCB board decreases, the conductive body is affected by the temperature, causing multiple adjacent conductive units to shrink and move away from each other in the slot channel. This avoids the problem of decreased connection stability between the conductive body and the substrate due to the overall shrinkage of the conductive body. It can be seen that the setting of the slot channel can also improve the connection stability between the conductive body and the substrate. Meanwhile, during heating and cooling cycles, the rigid conductive body cannot release accumulated stress, leading to further changes in the surface flatness of the conductive body. This results in inconsistent detection data from the sensor under the same temperature and sensing conditions. However, when a slot channel is placed on the conductive body, as the ambient temperature of the PCB board increases or decreases, the multiple conductive units formed by the slot channel move closer or further apart due to thermal expansion or contraction. The size of the slot channel decreases or increases in the direction parallel to the top plane of the substrate. This provides space for deformation of the multiple conductive units, reducing the stress acting on the conductive body, improving the overall flatness of the conductive body, enhancing the stability of the transmitted signal, and reducing the probability of zero-point offset, thereby improving the measurement accuracy of the sensor.

[0040] (2) In this invention, the gap channel includes multiple transverse channels, which divide the conductive body into multiple conductive units. A conductive unit is formed between two adjacent transverse channels. The gap channel also includes multiple longitudinal channels, which are connected to and positioned on the transverse channels to divide the conductive units into sub-conductive units. When the PCB board is subjected to thermal expansion, the transverse channels can provide deformation space for thermal expansion between two adjacent conductive units, and the longitudinal channels can provide deformation space for thermal expansion between two adjacent sub-conductive units. This provides space for thermal expansion deformation of the entire conductive body, preventing compression and stress accumulation after thermal expansion, which would otherwise lead to a decrease in the flatness of the upper surface of the conductive unit.

[0041] (3) In this invention, the PCB board further includes conductive connectors disposed within the longitudinal channel, with both ends of the conductive connectors connected to two adjacent sub-conductive units. The conductive connectors are mainly used to provide stable electrical connection continuity between two adjacent sub-conductive units. The two adjacent conductive units can be connected to each other at the edge of the conductive body. The continuity of the conductive body is further improved, and the electrical connection between the sensor and the conductive body is more stable. Attached Figure Description

[0042] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of the present invention.

[0043] Figure 1 This is a schematic top view of the substrate and the conductive mechanism according to a preferred embodiment of the present invention;

[0044] Figure 2 yes Figure 1 A schematic diagram of a cross-sectional view from the perspective of the AA (Anti-Aggressive) plane;

[0045] Figure 3 yes Figure 2 A partial schematic diagram of A in the middle;

[0046] Figure 4 This is a cross-sectional schematic diagram of a conductive body installed in a substrate receiving groove in one embodiment of the present invention;

[0047] Figure 5 This is a cross-sectional view of another embodiment of the present invention showing an arcuate groove formed in a longitudinal channel;

[0048] Figure 6 This is a cross-sectional schematic diagram of another embodiment of the present invention, showing an arcuate groove formed in a transverse channel;

[0049] Figure 7 This is a schematic top view of a preferred embodiment of the present invention, showing that the slit channel includes multiple transverse channels and multiple longitudinal channels;

[0050] Figure 8 This is a schematic top view of one embodiment of the present invention, showing that the slit channel includes multiple transverse channels and multiple longitudinal channels;

[0051] Figure 9 This is a schematic top view of another embodiment of the present invention, showing that the slit channel includes multiple annular channels;

[0052] Figure 10 yes Figure 9 A partial schematic diagram of B in the diagram;

[0053] Figure 11This is a schematic top view of an embodiment of the present invention, showing that the conductive connector is composed of a sixth connector, a seventh connector, an eighth connector, and a ninth connector.

[0054] Figure 12 This is a schematic cross-sectional view of the electrical connection between the accelerometer sensor and the PCB board according to a preferred embodiment of the present invention;

[0055] Figure 13 This is a cross-sectional schematic diagram illustrating the steps of a circuit board manufacturing method according to an embodiment of the present invention.

[0056] Reference numerals: 1. Substrate; 11. Receiving groove; 12. Solder mask layer; 2. Conductive mechanism; 21. Conductive body; 211. Conductive unit; 2111. Sub-conductive unit; 22. Gap channel; 221. Lateral channel; 2211. Arrangement area; 222. Longitudinal channel; 223. Annular channel; 2231. First annular channel; 2232. Second annular channel; 23. Conductive connector; 231. First connector; 232. Second connector; 233. Third connector; 234. Fourth connector; 235, Fifth connector; 236, Sixth connector; 237, Seventh connector; 238, Eighth connector; 239, Ninth connector; 24, First space; 25, Second space; 26, Third space; 27, First body; 271, Fourth space; 28, Second body; 29, Arc-shaped groove; 291, First arc-shaped groove; 292, Second arc-shaped groove; 293, Arc-shaped deformation groove; 3, Anti-fall component; 4, Accelerometer; 41, Sensor body; 42, Pin. Detailed Implementation

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0058] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0059] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0060] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections 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 invention based on the specific circumstances.

[0061] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0062] refer to Figures 1 to 6 The first aspect of this invention provides a PCB board with reduced thermal expansion stress, comprising a substrate 1, which provides basic support for the PCB board. It should be noted that the substrate 1 can be made of various materials. For example, it can be an FR-4 epoxy resin glass fiber cloth substrate 1, or a polyimide substrate 1. The thickness of the substrate 1 can be adjusted according to actual application requirements.

[0063] See Figures 1 to 12 The PCB board includes a conductive mechanism 2, which includes a conductive body 21 disposed at the top of the substrate 1. A sensor is adapted to connect to the PCB board; specifically, the sensor is electrically connected to the conductive body 21. The signal detected by the sensor can be transmitted to the chip through the conductive body 21 and the circuitry in the PCB board. It should be noted that the conductive body 21 can be fixed to the top of the substrate 1 by bonding, soldering, or other methods. The material of the conductive body 21 can be a metal or alloy with good conductivity, such as copper, aluminum, or their alloys, to ensure better electrical connection with the sensor during use and smoother signal transmission.

[0064] In a preferred embodiment, the sensor is an accelerometer 4. In some other optional embodiments, the sensor may also be an infrared sensor, a vision sensor, etc.

[0065] Further, see 3 to Figure 11 The conductive body 21 has multiple slot channels 22 that penetrate the top and bottom of the conductive body 21. The multiple slot channels 22 can separate the conductive body 21 and form multiple conductive units 211 in the conductive body 21.

[0066] For example, the slot channels 22 can be formed on the conductive body 21 using processes such as laser cutting or chemical etching. The width and length of the slot channels 22 can be designed according to the size of the conductive body 21 and the required deformation characteristics. In this way, the conductive body 21 is divided into multiple relatively movable conductive units 211, for example, two, three or more conductive units can be formed.

[0067] Specifically, the gap channel 22 provides a deformable space for each of the conductive units 211. For example, when the ambient temperature of the PCB board increases, adjacent conductive units 211 are affected by thermal expansion and move closer to each other into the gap channel 22; when the ambient temperature of the PCB board decreases, adjacent conductive units 211 are affected by cold contraction and move away from each other in a direction away from the gap channel 22. In existing technologies, the slit channel 22 is not provided. When the conductive body 21 is affected by temperature, expanding when heated or contracting when cooled, the conductive body 21 deforms. Since the conductive body 21 is fixedly connected to the substrate 1, the conductive body 21 will compress the substrate 1. The substrate 1 provides a reaction force to the conductive body 21, which is stress. All or part of the stress will act on the top of the conductive body 21, causing deformation of the upper surface of the conductive body 21. The flatness of the upper surface of the conductive body 21 is damaged. At this time, the electrical connection between the conductive body 21 and the sensor is affected, which will lead to inaccurate measurement by the sensor. At the same time, the change in the flatness of the conductive body 21 will cause the internal sensing element of the sensor to deviate from the preset position, resulting in zero-point offset of the sensor.

[0068] In summary, the sensor is suitable for electrical connection with the conductive body 21. The slit channel 22 is formed on the conductive body 21 and divides the conductive body 21 into multiple conductive units 211. The slit channel 22 provides space for deformation of the multiple conductive units 211. When the ambient temperature of the PCB board increases, the conductive body 21 is affected by the temperature, causing multiple adjacent conductive units 211 to move closer to each other within the slit channel 22. At this time, the slit channel 22 provides deformation space for the thermal expansion of the multiple conductive units 211, effectively reducing the stress caused by the thermal expansion of the conductive body 21, improving the surface flatness of the conductive body 21, thereby improving the stability of the electrical connection between the sensor and the conductive body 21, and effectively suppressing the occurrence of zero-position shift in some sensors. When the ambient temperature of the PCB board decreases, the conductive body 21 is affected by the temperature, causing multiple adjacent conductive units 211 to shrink and move away from each other within the gap channel 22. This avoids the problem of decreased connection stability between the conductive body 21 and the substrate 1 due to the overall shrinkage of the conductive body 21. Therefore, the gap channel 22 can also improve the connection stability between the conductive body 21 and the substrate 1. Simultaneously, during heating and cooling cycles, the rigid conductive body 21 cannot release accumulated stress, leading to further changes in the surface flatness of the conductive body 21. This results in inconsistent detection data from the sensor under the same temperature and sensing adjustment conditions. When the slot channel 22 is disposed on the conductive body 21, when the ambient temperature of the PCB board increases or decreases, the multiple conductive units 211 formed by the slot channel 22 will move closer or further apart due to thermal expansion or contraction. In the direction parallel to the top plane of the substrate, the size of the slot channel 22 will decrease or increase. This provides a deformable space for the multiple conductive units 211, reducing the stress acting on the conductive body 21, improving the overall flatness of the conductive body 21, enhancing the stability of the transmitted signal, reducing the probability of zero-position offset, and thus improving the measurement accuracy of the sensor.

[0069] It should be further explained that, since the substrate 1 is mainly used to provide protection and the conductive body 21 is mainly used to provide electrical support, their functions are inconsistent. Therefore, the substrate 1 and the conductive body 21 are made of different materials, and their coefficients of thermal expansion are different. Thus, when the PCB board is heated, the substrate 1 and the conductive body 21 are heated together, resulting in inconsistent deformation of the substrate 1 and the conductive body 21. Consequently, the substrate 1 and the conductive body 21 generate stress during thermal expansion, causing a decrease in the surface flatness of the conductive body 21.

[0070] See Figure 7 and Figure 8 In a preferred embodiment, the gap channel 22 includes a plurality of transverse channels 221, all of which are arranged along the length extension direction of the conductive body 21.

[0071] Specifically, this arrangement divides the conductive body 21 into multiple strip-shaped conductive units 211 extending along the length direction. When the multiple conductive units 211 expand when heated or contract when cooled, these strip-shaped conductive units 211 can be relatively displaced along the width direction of the substrate 1, thereby effectively reducing the stress caused by the deformation of the conductive units 211 and improving the surface flatness of the conductive body 21.

[0072] Furthermore, a conductive unit 211 is formed between two adjacent transverse channels 221, and the inner wall of each transverse channel 221 is at a certain distance from the outer wall of the conductive body 21. Therefore, in this embodiment, two adjacent conductive units 211 are interconnected at the edge of the conductive body 21, meaning the electrical connection of multiple conductive units 211 is uninterrupted. This ensures the continuity of the electrical connection between the multiple conductive units 211, improves the signal stability between the sensor and the conductive body 21, and prevents structural failures that might occur due to the slit channel 22 penetrating the edge of the conductive body 21. In this embodiment, the multiple conductive units 211 divided by the multiple transverse channels 221 are of the same size. While ensuring that adjacent conductive units 211 can move relative to the transverse channels 221, the conductive body 21 has more uniform electrical connection performance.

[0073] In a preferred embodiment, the gap channel 22 is provided with an edge of at least 0.05 nm from the edge of the conductive body 21. This ensures that solder paste will not leak from the side when the sensor is soldered to the conductive body 21, and further ensures the continuity of the electrical connection of the conductive body 21.

[0074] See Figure 7 and Figure 8 The gap channel 22 includes a plurality of longitudinal channels 222, which are arranged along the width extension direction of the conductive body 21. Each longitudinal channel 222 is connected to a corresponding transverse channel 221 to divide each conductive unit 211 into a sub-conductive unit 2111.

[0075] Therefore, while the transverse channel 221 provides deformation space along the width direction of the substrate 1 for two adjacent conductive units 211, the longitudinal channel 222 can divide the conductive unit 211 into sub-conductive units 2111. Two adjacent sub-conductive units 2111 can move relative to each other in the direction of the longitudinal channel 222. In other words, the longitudinal channel 222 provides deformation space along the length direction of the substrate 1 for two adjacent sub-conductive units 2111. Thus, by configuring the transverse channel 221 and the longitudinal channel 222, the conductive body 21 can have deformation space in both the length and width directions along the substrate 1. The stress generated by the deformation of the conductive body 21 can be further reduced, further improving the flatness of the conductive body 21 surface, thereby improving the accuracy and stability of the electrical connection between the sensor and the conductive body 21.

[0076] Meanwhile, the PCB board also includes a conductive connector 23, which is disposed within the longitudinal channel 222. The two ends of the conductive connector 23 are respectively connected to two adjacent sub-conductive units 2111. It should be noted that the conductive connector 23 is mainly used to provide stable electrical connection continuity between the two adjacent sub-conductive units 2111. As described above, the two adjacent conductive units 211 can be connected to each other at the edge of the conductive body 21. Therefore, in this embodiment, the continuity of the conductive body 21 is further improved, and the electrical connection between the sensor and the conductive body 21 is more stable.

[0077] In summary, through the above technical solution, the original multiple transverse channels 221 form multiple conductive units 211 on the conductive body 21. Furthermore, a longitudinal channel 222 extending along the width of the substrate 1 is introduced based on the transverse channels 221, thereby forming more refined and gridded sub-conductive units 2111 on each conductive unit 211. This multi-directional arrangement of the slot channels 22 allows the conductive body 21 to more comprehensively and uniformly absorb and disperse thermal expansion stress from different directions, effectively avoiding stress concentration problems that may occur with a single-direction slot channel 22, and significantly improving the flatness of the top surface of the conductive body 21 under complex thermal environments.

[0078] In a preferred embodiment of this example, see [reference]. Figure 7 The two ends of the conductive connector 23 are respectively connected to one side edge of two adjacent sub-conductive units 2111. The middle part of the conductive connector 23 extends towards the other side edge of the sub-conductive unit 2111 with a first protrusion. A first space 24 is formed in the middle of the first protrusion. The first space 24 is connected to a transverse channel 221 near one side edge of the sub-conductive unit 2111. A second space 25 and a third space 26 are formed between the first protrusion and the two sub-conductive units 2111, respectively. The second space 25 and the third space 26 are both connected to the transverse channel 221 near the other side edge of the sub-conductive unit 2111.

[0079] Specifically, see Figure 7 Each pair of adjacent transverse channels 221 has an arrangement area 2211, and the conduction unit 211 is disposed in the corresponding arrangement area 2211. Between two adjacent sub-conducting units 2111, the first space 24, the second space 25 and the third space 26 are arranged alternately between the two adjacent transverse channels 221, and the conduction connector 23 is divided into a first connector 231, a second connector 232, a third connector 233, a fourth connector 234 and a fifth connector 235 arranged vertically in sequence.

[0080] Furthermore, one end of the first connector 231 is connected to one side edge of one of the sub-conducting units 2111, one end of the fifth connector 235 is connected to one side edge of the other sub-conducting unit 2111, and the two ends of the third connector 233 are respectively vertically disposed at one end of the second connector 232 and the fourth connector 234. The other end of the second connector 232 is connected to the other end of the first connector 231, and the other end of the fourth connector 234 is connected to the other end of the fifth connector 235.

[0081] Specifically, by introducing the first connector 231, the second connector 232, the third connector 233, the fourth connector 234, and the fifth connector 235, which have a sequentially vertically arranged structure, the conductive connectors 23 are cleverly endowed with sufficient flexibility while maintaining reliable electrical and mechanical connections between adjacent conductive units 211. When the conductive connectors 23 experience relative displacement due to thermal expansion, they can buffer and adapt to this displacement through their own elastic deformation, effectively preventing connection breakage or fatigue failure. This ensures the stability and reliability of the substrate 1 and the conductive body 21 under long-term high-temperature operating conditions, further improving the overall performance and service life of the substrate 1 and the conductive body 21.

[0082] Therefore, in this embodiment, when the temperature rises, two adjacent sub-conducting units 2111 undergo thermal expansion deformation and move closer to each other, with the first connector 231 and the second connector 232 moving closer to each other relative to the fourth connector 234 and the fifth connector 235. When the temperature decreases, two adjacent sub-conducting units 2111 undergo cold contraction deformation and move away from each other, with the first connector 231 and the second connector 232 moving away from each other relative to the fourth connector 234 and the fifth connector 235. That is, the first space 24, the second space 25, and the third space 26 provide a deformable space for the conductive connector 23 as a whole. Specifically, this design allows the conductive connector 23 to absorb the relative displacement generated by the multiple conductive units 211 during thermal expansion through its own elastic deformation while maintaining the mechanical connection strength, thereby avoiding stress concentration or connection breakage caused by the rigid connection of the multiple conductive units 211.

[0083] This design effectively ensures the stability of the electrical connection between two adjacent sub-conducting units 2111. Secondly, it ensures that when two adjacent sub-conducting units 2111 undergo thermal expansion or cold contraction deformation, the conductive connector 23 also has space for deformation within the longitudinal channel 222, thus avoiding interference with the deformation of the two adjacent sub-conducting units 2111.

[0084] It should be noted that in this embodiment, the spacing between two adjacent slit channels 22 is between 0.1 nm and 0.25 nm, thereby ensuring that the conductive connector 23 has sufficient mechanical strength to prevent the conductive connector 23 from breaking when the sensor is connected to the conductive body 21.

[0085] In other optional embodiments of this example, the first space 24 may not be limited to one; there may be multiple first spaces 24. These multiple first spaces 24 may be respectively formed in the first protrusion and staggered with two adjacent transverse channels 221. For example: see... Figure 8 The first space 24 has three parts. The first and third first spaces 24 are symmetrically arranged at both ends of the first protrusion and communicate with the transverse channel 221 on one side near the sub-conducting unit 2111. In the length direction of the substrate 1, the second first space 24 is located between the first and third first spaces 24, and the second first space 24 communicates with the transverse channel 221 on the other side near the sub-conducting unit 2111.

[0086] Specifically, the exact number of the first spaces 24 can be designed by those skilled in the art. A greater number of first spaces 24 results in a longer conductive connector 23, leading to better deformation performance between the two sub-conductive units 2111 between the two transverse channels 221. However, an excessively long conductive connector 23 will cause the corresponding longitudinal channel 222 to become longer, resulting in a poorer electrical connection between the sensor and the conductive body 21. Those skilled in the art need to design according to actual needs.

[0087] See Figure 3 , Figure 4 , Figure 7 as well as Figure 8 In some embodiments, the PCB board includes a fall arrestor 3 located within the gap channel 22.

[0088] Specifically, when the anti-falling component 3 is installed within the gap channel 22, there is a certain gap between the outer edge of the anti-falling component 3 and the corresponding inner edge of the gap channel 22. In a preferred embodiment of this invention, the anti-falling component 3 is rectangular, and the gap channel 22 is also rectangular. Therefore, there is a certain distance between the four sides of the anti-falling component 3 and the four inner edges of the corresponding gap channel 22. This distance is specifically set by those skilled in the art according to actual needs.

[0089] In some other optional embodiments of this embodiment, the anti-falling component 3 may also be annular, the gap channel 22 may also be annular, and there may be a certain distance between the two peripheral edges of the anti-falling component 3 and the two inner wall surfaces of the gap channel 22, so that the two adjacent conductive units 211 may deform.

[0090] It should be noted that, in a preferred embodiment, the sensor may, but is not limited to, be electrically connected to the conductive body 21 using solder paste. However, when the gap channel 22 is too large, solder paste may flow into it, causing interference to the relative movement of adjacent conductive units 211 when the ambient temperature on the PCB board rises or falls. Therefore, the anti-drop component 3 is mainly used to prevent the solder paste from falling into the gap channel 22 when the sensor is connected to the conductive body 21.

[0091] See Figure 5 and Figure 6 In some embodiments, arc-shaped grooves 29 are formed on the inner wall surfaces at both ends of the plurality of slot channels 22, and the arc-shaped grooves 29 communicate with the slot channels 22. Specifically, in one embodiment, each slot channel 22 may have two arc-shaped grooves 29, which are respectively located at both ends of the slot channel 22. When the temperature rises, the conductive unit 211 undergoes thermal expansion deformation. The two ends of the conductive unit 211 in the thickness direction of the substrate 1 can deform into the arc-shaped grooves 29, thereby releasing the stress generated by the deformation of the conductive body 21 in the thickness direction of the substrate 1 within the arc-shaped grooves 29, thereby improving the flatness of the top surface of the conductive body 21.

[0092] In another embodiment, the arcuate groove 29 may also be annular. The annular arcuate groove 29 can better provide deformation space in the thickness direction of the substrate 1 for each of the conductive units 211. It should be noted that, since the arcuate groove 29 is generally arc-shaped, the stress in each conductive unit 211 can be released more evenly along the arcuate surface of the arcuate groove 29.

[0093] Furthermore, the conductive body 21 includes a first body 27 and a second body 28, with the second body 28 disposed on the top of the PCB board and the first body 27 disposed on the second body 28. Specifically, in a preferred embodiment, the first body 27 and the second body 28 can be connected by bonding.

[0094] Meanwhile, the arc-shaped groove 29 includes a first arc-shaped groove 291 and a second arc-shaped groove 292 that are interconnected. The arc-shaped groove 29 is located at the end of the first body 27 that is close to the PCB board, and the second arc-shaped groove 292 includes the end of the second body 28 that is away from the PCB board.

[0095] Therefore, the arrangement of the first body 27 and the second body 28 allows for separate processing of the first body 27 and the second body 28, enabling the arc-shaped groove 29 to be formed on the first body 27 and the second arc-shaped groove 292 to be formed on the second body 28. This ensures that the arc-shaped groove 29 can be formed on the conductive body 21. Specifically, the first body 27 can be processed first to form the gap channel 22 and the first arc-shaped groove 291. Then, the second body 28 can be processed to form the gap channel 22 and the second arc-shaped groove 292. Finally, the processed first body 27 and the processed second body 28 can be stacked together.

[0096] Furthermore, in some embodiments, a plurality of fourth spaces 271 may be formed between the first body 27 and the second body 28, the fourth spaces 271 being located inside the conductive unit 211. During the processing of the first body 27 and the second body 28, some of the fourth spaces 271 may be formed on the first body 27, and others may be formed on the second body 28. When the temperature rises, the conductive unit 211 with the fourth spaces 271 expands due to heat and deforms into the fourth spaces 271. Since the fourth spaces 271 are formed inside the conductive unit 211...

[0097] It should be noted that the connection method between the first body 27 and the second body 28 includes, but is not limited to, bonding.

[0098] See Figures 2 to 4 The substrate 1 has at least one receiving groove 11 at its top, and the conductive body 21 is disposed in the receiving groove 11. The receiving groove 11 provides a receiving space for the connection of the conductive body 21 and can protect the conductive body 21. One end of the anti-falling member 3 is connected to the bottom wall of the receiving groove 11, and the other end extends within the gap channel 22.

[0099] See Figure 4An arc-shaped deformation groove 293 can be formed on the side wall of the receiving groove 11, and the arc-shaped deformation groove 293 communicates with the receiving groove 11. The conductive body 21 is disposed in the receiving groove 11. When the ambient temperature of the PCB board increases, the conductive body 21 can thermally expand and deform into the arc-shaped deformation groove 293. The arc-shaped deformation groove 293 can provide a space for the outer wall of the conductive body 21 to accommodate deformation, thereby further reducing the stress of the conductive body 21, improving the surface flatness of the conductive body 21, and improving the stability and accuracy of the electrical connection between the sensor and the conductive body 21. At the same time, the arc-shaped deformation groove 293 can also provide a space for the substrate 1 to deform. When the temperature rises, the substrate 1 will also thermally expand, thereby deforming into the arc-shaped deformation groove 293, thereby further reducing the stress borne by the conductive body 21.

[0100] Meanwhile, the PCB board includes a solder mask layer 12, which is disposed at the top of the substrate 1. The solder mask layer 12 covers the top of the substrate 1. In a preferred embodiment, the solder mask layer 12 is made of an insulating material, which can protect the substrate 1. The solder mask layer 12 has a communicating channel that communicates with the receiving groove 11. In a direction parallel to the top plane of the substrate 1, the size of the communicating channel is greater than or equal to the opening size of the receiving groove 11. Therefore, the communicating channel provides a passage for the connection between the sensor and the conductive body 21.

[0101] It should be noted that the sensor can be an accelerometer 4, or it can be an infrared sensor, a vision sensor, etc.

[0102] See Figures 9 to 11 In some other alternative embodiments, the slit channel 22 is an annular channel 223, which includes a first annular channel 2231 and a second annular channel 2232 arranged concentrically.

[0103] Therefore, the conductive body 21 is divided into three parts by the first annular channel 2231 and the second annular channel 2232, thereby forming three conductive units 211. In a direction parallel to the top plane of the substrate, one conductive unit 211 is formed between the first annular channel 2231 and the second annular channel 2232, and the other two conductive units 211 are formed on the inner side of the first annular channel 2231 and the outer side of the second annular channel 2232, respectively. When the multiple conductive units 211 expand due to heat or contract due to cold, two adjacent conductive units 211 can be relatively displaced towards the first annular channel 2231 or the second annular channel 2232, effectively absorbing stress. In this embodiment, the first annular channel 2231 and the second annular channel 2232 are compared to... Figure 7 and Figure 8 The gap channel 22 is easier to process, improving production efficiency and saving costs. At the same time, the two side walls of the three conductive units 211, which are composed of the first annular channel 2231 and the second annular channel 2232, are circular in the direction parallel to the top plane of the substrate. This can better disperse stress, so that the stress can be better released when two adjacent conductive units 211 move relative to each other, further improving the surface flatness of the conductive body 21.

[0104] See Figure 9 and Figure 10 The conductive mechanism 2 includes multiple conductive connectors 23, which are located within the first annular channel 2231 and the second annular channel 2232, and connected to two adjacent conductive units 211. The multiple conductive connectors 23 within the first annular channel 2231 are arranged in a ring around the centerline of the first annular channel 2231, and the multiple conductive connectors 23 within the second annular channel 2232 are arranged in a ring around the centerline of the second annular channel 2232. The conductive connectors 23 are used to improve the stability of the electrical connection between two adjacent conductive units 211.

[0105] Specifically, the conductive connector 23 is a structural element disposed inside the first annular channel 2231 and the second annular channel 2232, and its main function is to connect adjacent conductive units 211. Multiple conductive connectors 23 can be integrally formed from the same material as the conductive body 21, for example, through a precise etching process. Multiple conductive connectors 23 are arranged in a ring around the centerline of the first annular channel 2231 and the second annular channel 2232, forming a distributed connection network. This arrangement ensures that the conductive units 211 maintain structural continuity and stability during thermal expansion, avoiding localized stress concentration or uneven deformation.

[0106] In a preferred embodiment of this invention, it should be noted that each conductive connector 23 includes at least a sixth connector 236 and a seventh connector 237 connected sequentially. The conductive connector 23 is generally V-shaped, and the length extension direction of the sixth connector 236 and the length extension direction of the seventh connector 237 have a preset angle. The preset angle can be selected by those skilled in the art as needed. Furthermore, when the PCB board deforms due to thermal expansion or contraction, two adjacent conductive units 211 move relative to each other, and the preset angle in the generally V-shaped conductive connector 23 can be reduced or increased, thus providing a better deformation effect for the conductive connector 23.

[0107] Meanwhile, the two ends of the connection between the sixth connector 236 and the seventh connector 237 are rounded to disperse the stress acting on the connection between the sixth connector 236 and the seventh connector 237 and improve the service life of the conductive connector 23.

[0108] In summary, the overall geometry of the conductive connector 23 is designed as a "V-shape." This V-shaped structure gives the conductive connector 23 unique flexibility, allowing adjacent conductive units 211 to move closer together when heated and expanding, and for the sixth connector 236 and the seventh connector 237 in the conductive connector 23 to move closer together. That is, the conductive connector 23 can absorb and release energy by changing the V-angle or bending when subjected to thermal stress. The V-shaped conductive connector 23 is typically formed in the conductive body 21 using a precise etching process.

[0109] In some other optional embodiments of this example, the conductive connector 23 is generally W-shaped, and includes a sixth connector 236, a seventh connector 237, an eighth connector 238, and a ninth connector 239 connected sequentially. The length extension direction of the sixth connector 236 has a preset angle with the length extension direction of the seventh connector 237, the length extension direction of the seventh connector 237 has a preset angle with the length extension direction of the eighth connector 238, and the length extension direction of the eighth connector 238 has a preset angle with the length extension direction of the ninth connector 239. Similarly, when the PCB board deforms due to thermal expansion or contraction, the two adjacent conductive units 211 move relative to each other, and the preset angles in the W-shaped conductive connector 23 can decrease or increase, resulting in better deformation performance of the conductive connector 23. Furthermore, the W-shaped conductive connector 23 also exhibits better deformation performance.

[0110] It should be noted that when the slit channel 22 adopts a concentric annular channel structure, the conductive body 21 is divided into three concentric annular or disc-shaped conductive units 211. This highly symmetrical structure allows the conductive body 21 to uniformly absorb and disperse thermal stress outward from the center when it expands due to heat. The conductive units 211 between the first annular channel 2231 and the second annular channel 2232, as well as the conductive units 211 on the inner side of the first annular channel 2231 and the outer side of the second annular channel 2232, work together to achieve multi-level, refined deformation management. This is particularly important for the connection between the conductive body 21 and components such as circular or quasi-circular sensors that require high-precision dimensional stability, significantly improving their reliability and performance in high-temperature environments.

[0111] In summary, regardless of whether the embodiment employs the arrangement of the transverse channel 221 and the longitudinal channel 222 in the conductive body 21, or the embodiment employs the first annular channel 2231 and the second annular channel 2232, the solution of this application optimizes the specific geometric configuration of the slit channel 22. This solves the problem that the conductive body 21 lacks deformation space during thermal expansion, leading to varying degrees of material deformation under different coefficients of thermal expansion. Consequently, the conductive body 21 is subjected to compression and stress, which damages the flatness of the top surface of the conductive body 21 and affects the stability and accuracy of the electrical connection between the sensor and the conductive body 21. Furthermore, it also solves the problem that during the cyclic process of thermal expansion and contraction of the conductive body 21, the lack of deformation space causes the conductive body 21 to expand and contract repeatedly on the top of the substrate 1, affecting the connection stability between the conductive body 21 and the substrate 1. In some cases, the stress generated during the repeated expansion and contraction of the conductive body 21 can be transmitted to the sensor electrically connected to the conductive body 21, potentially damaging the measuring element in the sensor.

[0112] A second aspect of the present invention provides an acceleration sensing system, comprising: a PCB board as described above and an acceleration sensor 4, the acceleration sensor 4 being located at the top of the PCB board, the acceleration sensor 4 including a sensor body 41 and pins 42, one end of the pins 42 being electrically connected to the sensor body 41, and the other end being electrically connected to the conduction mechanism 2 disposed on the substrate 1.

[0113] Specifically, in a preferred embodiment, the substrate 1 has a plurality of receiving slots 11, which are equally spaced on the substrate 1. The substrate 1 also has a plurality of pins 42 and conductive bodies 21, with the same number of pins 42, conductive bodies 21, and receiving slots 11. A corresponding conductive body 21 is disposed in a corresponding receiving slot 11. The plurality of pins 42 in the accelerometer 4 are electrically connected to the plurality of conductive bodies 21. The electrical connection between the pins 42 and the conductive bodies 21 can be, but is not limited to, using solder paste.

[0114] Therefore, when the ambient temperature of the PCB board rises or falls, the conductive body 21 corresponding to the pin 42 undergoes thermal expansion or cold contraction deformation. The adjacent conductive units 211 in the conductive body 21 move relative to each other, thereby releasing the stress and effectively improving the flatness of the surface of the conductive body 21 caused by thermal stress. In other words, it effectively blocks the transmission path of thermal stress to the inside of the sensor, achieving the effect of maintaining the sensor's measurement accuracy and temperature cycle data consistency.

[0115] It should be further noted that, in a preferred embodiment, the sensor body 41 has a receiving space containing a chip, an electrolyte solution, and a mass block. The chip is fixed to the inner wall of the receiving space, the electrolyte solution fills the receiving space, and the mass block is located within the receiving space. When the accelerometer 4 moves, the mass block moves in the electrolyte solution, causing the electrolyte solution to move synchronously. The chip measures the corresponding acceleration by sensing the changes in the electrolyte solution.

[0116] While the accelerometer 4 and the conductive body 21 are transmitting signals to each other, the surface flatness of the conductive body 21 is disrupted by stress. This stress is transmitted to the interior of the accelerometer 4, causing the mass block to deviate from its equilibrium position, resulting in a zero-position shift in the accelerometer 4. This invention, through the design of the slit channel 22, improves the flatness of the top surface of the conductive body 21, effectively reducing the occurrence of zero-position shift in the accelerometer 4 and improving its detection accuracy.

[0117] Through the above technical solutions, the acceleration sensing system solves the problem of sensor accuracy drift caused by high-temperature environments, and is particularly suitable for high-temperature application scenarios that require long-term stable operation, such as automotive electronics and industrial control.

[0118] A third aspect of this application provides a method for manufacturing a circuit board (PCB), wherein the manufacturing steps of the circuit board are as follows:

[0119] S1: Fix the substrate 1 and the conductive body 21 to the preset positions respectively.

[0120] The substrate 1 is fixed in a preset position, and the fixing method may be, but is not limited to, a clamp. The conductive body 21 is fixed, and the fixing position may be, but is not limited to, a worktable.

[0121] S2: The slit channel 22 is formed on the conductive body 21 by an etching process.

[0122] See Figure 13As described in step S1, the conductive body 21 is fixed. Those skilled in the art can first clean the conductive body 21 to remove oil, oxide layers, and impurities, preparing it for subsequent process steps. Then, a resist layer is applied to the area to be retained. In this embodiment, the gap channel 22 is not covered by the resist layer. Next, an etching solution is applied to the conductive body 21 and maintained at a preset temperature and time to form the gap channel 22. Finally, the resist layer is removed, and the conductive body 21 is cleaned. Specifically, the PCB board can be placed in a special stripping solution or a heated sodium hydroxide solution to dissolve and remove the resist layer.

[0123] See Figure 5 and Figure 6 In the preferred embodiment described above, a circuit board manufacturing method is proposed to form the gap channel 22 on the conductive body 21 by etching. However, when the conductive body 21 is composed of multiple parts (e.g., the first body 27 and the second body 28) and a complex structure (e.g., the gap channel 22 and the arc groove 29) needs to be formed, directly processing the conductive body 21 using a single etching process may face problems such as difficulty in controlling processing accuracy, inconsistent etching effects for different materials or thicknesses, and insufficient connection strength of the final structure, thereby affecting the deformation compensation effect of the conductive mechanism at high temperatures.

[0124] Therefore, in some embodiments, in step S2, the gap channel 22 and the arc groove 29 in the first body 27 can be processed sequentially, and the gap channel 22 and the second arc groove 292 in the second body 28 can be processed sequentially. Then, a bonding process is used to connect the first body 27 to the top of the second body 28.

[0125] Specifically, this processing step refers to independently processing the first body 27 and the second body 28 before connecting them. The etching parameters can be optimized based on the material properties and structural requirements of the first body 27 to precisely form the required slot channel 22 and the first arc-shaped groove 291 within it. Similarly, the second body 28 can also be processed independently to form the slot channel 22 and the second arc-shaped groove 292 within it.

[0126] Furthermore, after processing the first body 27 and the second body 28, they can be stacked to make the slot channels 22 on the first body 27 and the second body 28 correspond to each other, and make the first arc-shaped groove 291 and the second arc-shaped groove 292 correspond to each other, thereby forming the arc-shaped groove 29. Through segmented processing of the first body 27 and the second body 28, the arc-shaped groove 29 can be processed more effectively.

[0127] Furthermore, this step-by-step processing method also allows for fine control over the materials, thickness, and feature dimensions of the first body 27 and the second body 28. For example, different masks, etching solution formulations, etching times, or etching powers can be used to ensure that the microstructures on the first body 27 and the second body 28 achieve the expected precision and morphology.

[0128] Furthermore, bonding is a technique for precisely connecting two or more independently processed components together. After the independent processing of the first body 27 and the second body 28 is completed, the first body 27 is firmly connected to the top of the second body 28 through bonding. The bonding process can include various specific methods. In a preferred embodiment of this example, since both the first body 27 and the second body 28 are made of copper, diffusion bonding can be used to achieve atomic bonding under high temperature and pressure for such metal materials. Specifically, the surfaces of the first body 27 and the second body 28 can be treated first to ensure their smoothness and gloss, and to remove oil and oxide layers. Then, a relative initial pressure is applied to the first body 27 and the second body 28. Finally, pressure is further applied to the first body 27 and the second body 28, and they are heated. At this time, the connection between the first body 27 and the second body 28 melts and bonds under the action of temperature and pressure. After continuing to hold the pressure and temperature for a certain period of time, the atoms at the connection between the first body 27 and the second body 28 fuse together to form the conductive body 21.

[0129] It should be further noted that, in the preferred embodiment, the width of the slit channel 22 is in the range of 0.05 nm to 0.15 nm. When the width of the slit channel 22 is less than 0.05 nm, in the etching process, there may be a problem of incomplete etching, that is, the slit channel 22 cannot penetrate the conductive body 21. When the width of the slit channel 22 is greater than 0.15 nm, it will result in the slit channel 22 being too large, thereby excessively reducing the effective welding area and affecting the welding strength and electrical connection performance between the accelerometer 4 and the conductive body 21.

[0130] S3: Connect the conductive body 21 to the top of the substrate 1.

[0131] The conductive body 21 is connected to the top of the substrate 1. The connection method can be, but is not limited to, welding, mechanical connection, adhesion, etc. In a preferred embodiment, the substrate 1 is provided with a receiving groove 11, and the size of the conductive body 21 matches the receiving groove 11, allowing the conductive body 21 to be disposed within the receiving groove 11.

[0132] In some other alternative embodiments, the conductive body 21 can also be directly disposed on the top of the substrate 1, and the solder mask layer 12 is provided on the PCB board. The solder mask layer 12 is disposed on the top of the substrate 1, and the size of the connecting channel in the solder mask layer 12 matches the size of the conductive body 21. Therefore, the inner wall surface of the connecting channel and the bottom end of the conductive body 21 can be used together to position the conductive body 21, thereby improving the connection strength between the conductive body 21 and the substrate 1.

[0133] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. A PCB board with reduced thermal expansion stress, characterized in that, include: substrate; A conductive mechanism includes a conductive body disposed at the top of the substrate. The conductive body has multiple slot channels extending through the top and bottom of the conductive body to divide the conductive body into multiple conductive units. When the temperature rises, the multiple conductive units expand and deform due to heat, causing two adjacent conductive units to move closer to each other within the gap channel, thereby improving the flatness of the upper surface of the conductive body at high temperatures.

2. The PCB board with reduced thermal expansion stress according to claim 1, characterized in that, The gap channel includes multiple transverse channels, all of which are arranged along the length extension direction of the conductive body. The conductive unit is formed between two adjacent transverse channels, and the inner wall of the edge of each transverse channel is at a certain distance from the outer wall of the conductive body.

3. The PCB board with reduced thermal expansion stress according to claim 2, characterized in that, The slot channel includes multiple longitudinal channels, all of which are arranged along the width extension direction of the conductive body. Each longitudinal channel is connected to a corresponding transverse channel to divide each conductive unit into sub-conductive units. The PCB board also includes a conductive connector, which is disposed in the longitudinal channel, and its two ends are respectively connected to two adjacent sub-conductive units.

4. The PCB board with reduced thermal expansion stress according to claim 3, characterized in that, The two ends of the conductive connector are respectively connected to one side edge of two adjacent sub-conductive units. The middle part of the conductive connector extends towards the other side edge of the sub-conductive unit with a first protrusion. A first space is formed in the middle of the first protrusion. The first space is connected to a transverse channel near one side edge of the sub-conductive unit. A second space and a third space are formed between the first protrusion and the two sub-conductive units, respectively. The second space and the third space are both connected to the transverse channel near the other side edge of the sub-conductive unit.

5. The PCB board with reduced thermal expansion stress according to claim 1, characterized in that, The PCB board includes a drop-proof component, which is located within the gap channel; When the anti-fall device is installed in the gap channel, there is a certain gap between the outer edge of the anti-fall device and the inner edge of the corresponding gap channel.

6. The PCB board with reduced thermal expansion stress according to claim 5, characterized in that, The top of the substrate is provided with at least one receiving groove, and the conductive body is disposed in the receiving groove; One end of the anti-falling component is connected to the bottom wall of the receiving groove, and the other end extends within the gap channel; The PCB board includes a solder mask layer disposed at the top of the substrate. The solder mask layer has a communication channel corresponding to the receiving groove and communicating with the receiving groove. In a direction parallel to the top plane of the substrate, the size of the communication channel is greater than or equal to the groove size of the receiving groove. or The top of the substrate is provided with at least one receiving groove, and the conductive body is disposed in the receiving groove; The side of the receiving groove has an arc-shaped deformation groove, which is connected to the receiving groove. When the temperature rises, the conductive body thermally expands and deforms into the arc-shaped deformation groove to improve the flatness of the upper surface of the conductive body at high temperature.

7. The PCB board with reduced thermal expansion stress according to claim 1, characterized in that, Arc-shaped grooves are formed on the inner wall surfaces at both ends of the plurality of slot channels, and the arc-shaped grooves are connected to the slot channels; The conductive body includes a first body and a second body. The second body is disposed on the top of the PCB board, and the first body is disposed on the second body. The arc-shaped groove includes a first arc-shaped groove and a second arc-shaped groove that are interconnected. The first arc-shaped groove is located at the end of the first body that is close to the PCB board, and the second arc-shaped groove is located at the end of the second body that is away from the PCB board. A plurality of fourth spaces are formed between the first body and the second body, and the fourth spaces are located inside the conductive unit.

8. The PCB board with reduced thermal expansion stress according to claim 1, characterized in that, The gap channel is an annular channel, which includes a first annular channel and a second annular channel arranged concentrically, and the first annular channel and the second annular channel divide the conductive body into three conductive units; The conduction mechanism includes multiple conduction connectors, which are located in the first annular channel and the second annular channel respectively and connected to two adjacent conduction units. The multiple conduction connectors in the first annular channel are arranged in a ring around the center line of the first annular channel, and the multiple conduction connectors in the second annular channel are arranged in a ring around the center line of the second annular channel. Each of the conductive connectors includes at least a sixth connector and a seventh connector connected in sequence. The conductive connector is generally V-shaped, and the length extension direction of the sixth connector has a preset angle with the length extension direction of the seventh connector.

9. An acceleration sensing system, characterized in that, include: The PCB board with reduced thermal expansion stress according to any one of claims 1-8; An accelerometer is located at the top of the PCB board. The accelerometer includes a sensor body and pins. One end of the pins is electrically connected to the sensor body, and the other end is electrically connected to the conduction mechanism disposed on the substrate.

10. A method for manufacturing a circuit board, used to manufacture a PCB board with reduced thermal expansion stress as described in any one of claims 1 to 8, characterized in that, include: S1: Fix the substrate and the conductive body to preset positions respectively; S2: The slit channel is formed on the conductive body by an etching process; S3: Connect the conductive body to the top of the substrate.

11. The method for manufacturing a circuit board according to claim 10, characterized in that, The conductive body includes a first body and a second body. The second body is disposed on the top of the PCB board, and the first body is disposed on the second body. Arc-shaped grooves are formed on the inner wall surfaces at both ends of the plurality of gap channels. The arc-shaped grooves include a first arc-shaped groove and a second arc-shaped groove that are interconnected. The first arc-shaped groove is located at the end of the first body that is close to the PCB board, and the second arc-shaped groove is located at the end of the second body that is away from the PCB board. The first body is processed, and the slit channel and the first arc-shaped groove are formed in the first body; The second body is processed, and the slit channel and the second arc-shaped groove are formed in the second body; The first body and the second body are stacked so that the first arc-shaped groove and the second arc-shaped groove are connected to each other to form the arc-shaped groove; The first body and the second body are fixedly connected by a bonding process.

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