Pressure sensor, pressure-sensitive circuit board, and manufacturing method of pressure-sensitive circuit board

Abstract

This application discloses a pressure-sensitive circuit board, including a circuit board, a plurality of conductive bumps, and a strain gauge. The circuit board includes a dielectric layer and conductive lines disposed on the dielectric layer. The plurality of conductive bumps are spaced apart on the conductive lines, with an accommodating space between each pair of adjacent conductive bumps. The strain gauge is disposed on the plurality of conductive bumps and covers the accommodating space. The strain gauge is used to deform under external force, and the accommodating space is used to accommodate at least a portion of the deformed strain gauge. Additionally, this application also provides a method for manufacturing a pressure-sensitive circuit. Furthermore, this application also incorporates a pressure sensor.

Description

Technical Field

[0001] This application relates to a pressure sensor, a pressure-sensitive circuit board, and a method for manufacturing the pressure-sensitive circuit board. Background Technology

[0002] With the development of smart living, intelligent devices are widely used in various fields, such as communications, medical care, automobiles, and industrial control. Most intelligent devices have pressure sensors.

[0003] Existing pressure sensors mainly consist of a substrate, a strain gauge, and a support. The support is positioned between the substrate and the strain gauge to create a gap. When the strain gauge is compressed, it undergoes elastic deformation and changes its resistance, with some of the strain gauge being squeezed into the gap. To ensure sufficient space within the gap to accommodate this deformed portion of the strain gauge, the support is often designed to be relatively tall. However, a tall support often results in a thicker pressure sensor, hindering its miniaturization. Summary of the Invention

[0004] To address the shortcomings of the prior art, this application provides a pressure-sensitive circuit board.

[0005] In addition, it is necessary to provide a method for manufacturing the pressure-sensitive circuit board described above.

[0006] In addition, it is necessary to provide a pressure sensor having the aforementioned pressure-sensitive circuit board.

[0007] A pressure-sensitive circuit board includes a circuit board, a plurality of conductive bumps, and a strain gauge. The circuit board includes a dielectric layer and conductive lines disposed on the dielectric layer. The plurality of conductive bumps are spaced apart on the conductive lines, and there is an accommodating space between each pair of adjacent conductive bumps. The strain gauge is disposed on the plurality of conductive bumps and covers the accommodating space. The strain gauge is used to deform under the action of an external force, and the accommodating space is used to accommodate at least a portion of the deformed strain gauge.

[0008] Further, the conductive line includes a first conductive line and a second conductive line spaced apart from the first conductive line, with a portion of the dielectric layer exposed between the first conductive line and the second conductive line. The conductive bumps include a plurality of first bumps and a plurality of second bumps, with the plurality of first bumps spaced apart on the first conductive line and the plurality of second bumps spaced apart on the second conductive line. The accommodating space includes a first accommodating space formed between every two adjacent first bumps and a second accommodating space formed between every two adjacent second bumps. The strain gauge includes a first strain gauge, a second strain gauge, and a third strain gauge; the first strain gauge is disposed on the first bump to cover the plurality of first accommodating spaces; the second strain gauge is disposed on the second bump to cover the plurality of second accommodating spaces; and the second strain gauge is disposed on the dielectric layer and connected to the first strain gauge and the second strain gauge.

[0009] Further, the conductive line includes a third conductive line and a fourth conductive line spaced apart from the third conductive line, with a portion of the dielectric layer exposed between the third and fourth conductive lines. The conductive bump includes a first conductor and a second conductor. The first conductor includes a first body portion and a plurality of third bumps protruding from the first body portion. The second conductor includes a second body portion and a plurality of fourth bumps protruding from the second body portion. The first body portion is disposed on the third conductive line, and the second body portion is disposed on the fourth conductive line. The accommodating space further includes a third accommodating space formed between every two adjacent third bumps and a fourth accommodating space formed between every two adjacent fourth bumps. The strain gauge includes a fourth strain gauge, a fifth strain gauge, and a sixth strain gauge. The fourth strain gauge is disposed on the third bump to cover the plurality of third accommodating spaces, the fifth strain gauge is disposed on the third bump to cover the plurality of fourth accommodating spaces, and a portion of the sixth strain gauge is disposed on the dielectric layer and connected to the fourth strain gauge and the fifth strain gauge.

[0010] Furthermore, the distance between any two adjacent conductive bumps is 18 to 30 micrometers.

[0011] Furthermore, the pressure-sensitive circuit board also includes a solder resist layer disposed on the strain gauge.

[0012] Furthermore, the strain body is made of a conductor and an adhesive, wherein the conductor includes at least one of silver nanowires, silver nanopowder, and carbon powder, and the adhesive includes at least one of polydimethylsiloxane and thermoplastic polyurethane.

[0013] Furthermore, the conductive bump is made of a metal or a combination of metal powder and an adhesive.

[0014] A method for manufacturing a pressure-sensitive circuit board includes the steps of: providing a circuit substrate, the circuit substrate including a dielectric layer and conductive lines disposed on the dielectric layer; distributing a plurality of conductive bumps at intervals on the conductive lines, with an accommodating space between each pair of adjacent conductive bumps; and distributing strain gauges on the conductive bumps, the strain gauges covering the accommodating spaces, thereby obtaining the pressure-sensitive circuit.

[0015] Furthermore, the conductive bumps are formed by electroplating or coating with silver paste.

[0016] A pressure sensor, comprising a pressure-sensitive circuit board as described above.

[0017] The pressure-sensitive circuit board provided in this application forms multiple accommodating spaces by spaced-apart conductive bumps. These accommodating spaces can be used to accommodate deformed portions of the strain, that is, the deformed portions of the strain are dispersed and filled into multiple accommodating spaces, thereby helping to reduce the overall thickness of the pressure-sensitive circuit board. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the copper-clad substrate provided in the first / second embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the copper-clad substrate after the first / second bumps are provided in the first embodiment of this application.

[0020] Figure 3 for Figure 2 The diagram shown is a schematic of a copper-clad substrate after part of the copper foil layer has been removed.

[0021] Figure 4 This is a schematic diagram of the pressure-sensitive circuit board provided in the first embodiment of this application.

[0022] Figure 5 for Figure 4 The diagram shows the pressure-sensitive circuit board under pressure.

[0023] Figure 6 for Figure 4 The diagram shown is a schematic of the pressure-sensitive circuit board after the first solder mask layer has been applied.

[0024] Figure 7 for Figure 4 The diagram shows the relationship between the resistance change rate of the strain gauge in the pressure-sensitive circuit board and the magnitude of the external force.

[0025] Figure 8 This is a schematic diagram of the copper-clad substrate after removing part of the copper foil layer provided in the second embodiment of this application.

[0026] Figure 9 for Figure 8The diagram shown is a schematic of a copper-clad substrate after the first / second conductor is installed.

[0027] Figure 10 This is a schematic diagram of the pressure-sensitive circuit board provided in the second embodiment of this application.

[0028] Figure 11 for Figure 10 The diagram shows the pressure-sensitive circuit board under pressure.

[0029] Figure 12 for Figure 10 The diagram shown is a schematic of the pressure-sensitive circuit board after the second solder mask layer has been applied.

[0030] Figure 13 for Figure 10 The diagram shows the relationship between the resistance change rate of the strain gauge in the pressure-sensitive circuit board and the magnitude of the external force.

[0031] Explanation of main component symbols

[0032] Pressure-sensitive circuit boards 100, 200

[0033] Copper clad substrate 10

[0034] Dielectric layer 11

[0035] Copper foil layer 12

[0036] First conductive line 121

[0037] Second conductive wire 122

[0038] Third conductive wire 123

[0039] Fourth conductive line 124

[0040] Pressing area 13

[0041] First pressing area 131

[0042] Second pressing area 132

[0043] Third pressure zone 133

[0044] Non-pressing area 14

[0045] First bump 21

[0046] Second protrusion 22

[0047] Third bump 23

[0048] Fourth bump 24

[0049] First variant 31

[0050] Second strain 32

[0051] Third variant 33

[0052] Fourth variant 34

[0053] Fifth variant 35

[0054] Sixth variant 36

[0055] First weld resist layer 40

[0056] First conductor 51

[0057] First body 511

[0058] Second conductor 52

[0059] Second Body 521

[0060] First accommodating space A

[0061] Second accommodating space B

[0062] Third accommodating space C

[0063] Fourth accommodating space D

[0064] Extension direction X Detailed Implementation

[0065] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0066] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component.

[0067] Please see Figures 1 to 5 The first embodiment of this application provides a method for manufacturing a pressure-sensitive circuit board 100, including the following steps:

[0068] S1: Please see Figure 1A copper-clad substrate 10 is provided, the copper-clad substrate 10 including a dielectric layer 11 and a copper foil layer 12 disposed on the dielectric layer 11. The copper-clad substrate 10 is divided into a pressing area 13 and a non-pressing area 14 (excluding the pressing area 13) along the extending direction X. The pressing area 13 is further divided into a first pressing area 131, a second pressing area 132, and a third pressing area 133 along the extending direction X. The second pressing area 132 is disposed between the first pressing area 131 and the third pressing area 133.

[0069] In this embodiment, the dielectric layer 11 can be made of a rigid material or a flexible material. The material of the dielectric layer 11 includes, but is not limited to, polyimide (PI), polyester resin (PET), polyethylene naphthalate two formicacid glycol ester (PEN), liquid crystal polymer (LCP), and modified polyimide (MPI).

[0070] In this embodiment, the copper-clad substrate 10 is a single-sided copper-clad substrate, and one copper foil layer 12 is disposed on one side of the dielectric layer 11. In other embodiments of this application, the copper-clad substrate 10 can be a double-sided copper-clad substrate, and two copper foil layers 12 are respectively disposed on opposite sides of the dielectric layer 11.

[0071] In this embodiment, the dielectric layer 11 is further provided with an embedded circuit layer (not shown in the figure), which is electrically connected to the copper foil layer so that the pressure-sensitive circuit board 100 subsequently manufactured has multiple circuit layers.

[0072] S2: Please see Figure 2 A plurality of first bumps 21 are electroplated on a portion of the copper foil layer 12 within the first pressing area 131, with a first accommodating space A between each adjacent pair of first bumps 21. A plurality of second bumps 22 are electroplated on a portion of the copper foil layer 12 within the third pressing area 133, with a second accommodating space B between each adjacent pair of second bumps 22. The plurality of first bumps 21 and the plurality of second bumps 22 constitute conductive bumps.

[0073] S3: Please see Figure 3A portion of the copper foil layer 12 within the second pressing area 132 is removed, resulting in a first conductive line 121 formed in the copper foil layer 12 within the first pressing area 131, and a second conductive line 122 formed in the copper foil layer 12 within the third pressing area 133. The first conductive line 121 and the second conductive line 122 constitute a conductive circuit. A first bump 21 is disposed on the first conductive line 121, and a second bump 22 is disposed on the second conductive line 122. A portion of the dielectric layer 11 is exposed in the second pressing area 132, thereby electrically isolating the first conductive line 121 and the second conductive line 122.

[0074] In other embodiments of this application, after removing a portion of the copper foil layer 12 within the second pressing area 132, the first bump 21 may be electroplated on the first conductive line 121, and the second bump 22 may be electroplated on the second conductive line 122.

[0075] S3: Please see Figure 4 A first strain gauge 31 is provided on the first bump 21, a second strain gauge 32 is provided on the second bump 22, and a third strain gauge 33 is provided between the first strain gauge 31 and the third strain gauge 33. Part of the third strain gauge 33 is provided on the dielectric layer 11, and another part of the third strain gauge 33 is provided on the side of the first bump 21 and the first conductive line 121, or on the side of the second bump 22 and the second conductive line 122, thus obtaining the pressure-sensitive circuit board 100.

[0076] Please see Figure 5 The first strained body 31, the second strained body 32 and the third strained body 33 will undergo elastic deformation under the action of external force, and the resistance value will change. The deformed part of the first strained body 31 can be filled into the first accommodating space A, and the deformed part of the third strained body 33 can be filled into the second accommodating space B.

[0077] In this embodiment, the first strain 31, the second strain 32, and the third strain 33 are made of conductive particles and an adhesive. The conductive particles include at least one of silver nanowires, silver nanopowder, and carbon powder, and the adhesive includes at least one of polydimethylsiloxane and thermoplastic polyurethane.

[0078] In this embodiment, the manufacturing method of the pressure-sensitive circuit board 100 further includes:

[0079] S4: Please see Figure 6A first solder resist layer 40 is provided on the first strained body 31, the second strained body 32, and the third strained body 33. The first solder resist layer 40 is also provided on the first conductive line 121 that is not covered by the first strained body 31 and the second conductive line 122 that is not covered by the second strained body 32.

[0080] Please see Figure 4 The first embodiment of this application also provides a pressure-sensitive circuit board 100, which includes a dielectric layer 11, a first conductive line 121, a second conductive line 122, a plurality of first bumps 21, a plurality of second bumps 22, a first strain gauge 31, a second strain gauge 32, and a third strain gauge 33. The first conductive lines 121 and second conductive lines 122 are spaced apart on the dielectric layer 11. The first bumps 21 are spaced apart on the first conductive lines 121, with a first accommodating space A between each adjacent pair of first bumps 21. The second bumps 22 are spaced apart on the second conductive lines 122, with a second accommodating space B between each adjacent pair of second bumps 22. The first strain gauge 31 is disposed on the first bumps 21. (See also...) Figure 5 When the first strained body 31 deforms, a portion of the first strained body 31 fills the first accommodating space A. The third strained body 33 is disposed on the second protrusion 22. When the third strained body 33 deforms, a portion of the third strained body 33 fills the second accommodating space B. The second strained body 32 connects the first strained body 31 and the third strained body 33.

[0081] In this embodiment, the first bump 21 and the second bump 22 are generally columnar. The first bump 21 is arranged in an array on the first conductive line 121, and the second bump 22 is arranged in an array on the second conductive line 122. The distance L between any two adjacent first bumps 21 or two adjacent second bumps 22 is 18 to 30 micrometers. This distance L is beneficial for matching the deformation of the first strain gauge 31 or the second strain gauge 32, so that the first accommodating space A or the second accommodating space B is not reserved too large and wasted space, nor is it reserved too small and cause the first strain gauge 31 or the second strain gauge 32 to overflow.

[0082] Please see Figure 5Specifically, when using the pressure-sensitive circuit board 100, the first conductive line 121 and the second conductive line 122 are electrically connected to an external circuit (not shown) to form a closed loop. When an external force is applied to the second pressing area 132, the second strain gauge 32 will generate a large deformation, while the first strain gauge 31 corresponding to the first pressing area 131 or the third strain gauge 33 corresponding to the third pressing area 133 will generate a smaller deformation. The deformed portion of the first strain gauge 31 fills the first accommodating space A, and the deformed portion of the third strain gauge 33 fills the second accommodating space B. At the same time, due to the deformation, the spacing between the conductive particles in the first strain gauge 31, the second strain gauge 32, and the third strain gauge 33 will increase, thereby increasing the resistance values ​​of the first strain gauge 31, the second strain gauge 32, and the third strain gauge 33. Moreover, the resistance change of the second strain gauge 32 with a larger deformation is greater than the resistance change of the first strain gauge 31 or the third strain gauge 33 with a smaller deformation. This change in resistance value is measured by the external circuit. Then, by applying different magnitudes of external force to the pressing area 13 multiple times, multiple different rates of resistance change can be obtained, thus establishing a one-to-one correspondence between the rate of resistance change and the magnitude of the external force. Please refer to [link to relevant documentation]. Figure 7 Based on this one-to-one correspondence and the actual measured rate of change of resistance, the magnitude of external force can be measured.

[0083] Compared with the prior art, the pressure-sensitive circuit board 100 provided in the first embodiment of this application has the following advantages:

[0084] (i) By setting multiple first protrusions 21 at intervals to form multiple first accommodating spaces A, and by setting multiple second protrusions 22 to form multiple second accommodating spaces B, the first accommodating space A can accommodate the deformed portion of the first strained body 31, and the second accommodating space B can be used to accommodate the deformed portion of the second strained body 32. That is, the deformed portion of the first strained body 31 is dispersed and filled into multiple first accommodating spaces A, or the deformed portion of the second strained body 32 is dispersed and filled into multiple second accommodating spaces B, thereby helping to reduce the overall thickness of the pressure-sensitive circuit board 100.

[0085] (ii) By dividing the pressing area 13 into a second pressing area 132 and a first pressing area 131 and a second pressing area 132 located on both sides of the second pressing area 132, when an external force is applied to the pressing area 13, the second strain 32 in the second pressing area 132 produces a larger deformation, while the first pressing area 131 and the second pressing area 132 produce a smaller deformation. This is beneficial to improving the resistance change rate and the sensitivity and accuracy of the measurement results.

[0086] (iii) The first strained body 31, which is the portion of the first accommodating space A that accommodates deformation, or the third strained body 33, which is the portion of the second accommodating space B that accommodates deformation, not only helps to protect the first strained body 31 or the third strained body 33, making it easy for them to return to their original state after the external force is removed, but also can delay the occurrence of a sudden change in resistance of the first strained body 31 or the third strained body 33. For example, if the third strained body 33, which is the portion of the first accommodating space A that accommodates deformation, is not included, the conductive particles in the third strained body 33 are likely to separate from each other when subjected to pressure, thereby causing a sudden change in resistance.

[0087] Please see Figure 1 , Figures 8 to 12 The second embodiment of this application provides a method for manufacturing a pressure-sensitive circuit board 200, including the following steps:

[0088] S5: Please see Figure 1 The copper-clad substrate 10 is provided. Along the extending direction X of the copper-clad substrate 10, the copper-clad substrate 10 is divided into a pressing area 13 and a non-pressing area 14 excluding the pressing area 13. The pressing area 13 is further divided along the extending direction X into a first pressing area 131, a second pressing area 132, and a third pressing area 133. The second pressing area 132 is disposed between the first pressing area 131 and the third pressing area 133.

[0089] S6: Please see Figure 8 A portion of the copper foil layer 12 within the pressing area 13 is removed to form a third conductive line 123 and a fourth conductive line 124. A portion of the dielectric layer 11 within the pressing area 13 is exposed between the third conductive line 123 and the fourth conductive line 124.

[0090] S7: Please see Figure 9 A first conductor 51 is disposed within the first pressing area 131. The first conductor 51 extends toward and partially covers the third conductive line 123. The first conductor 51 includes a first body 511 and a plurality of third protrusions 23 disposed on the first body 511. A third accommodating space C is provided between each adjacent pair of third protrusions 23. A second conductor 52 is disposed within the third pressing area 133. The second conductor 52 extends toward and partially covers the fourth conductive line 124. The second conductor 52 includes a second body 521 and a plurality of fourth protrusions 24 disposed on the second body 521. A fourth accommodating space D is provided between each adjacent pair of fourth protrusions 24. The third protrusions 23 and fourth protrusions 24 are generally hemispherical. The third protrusions 23 and fourth protrusions 24 are made of the same material, namely silver paste.

[0091] In this embodiment, step S7 includes: applying silver paste to the first pressing area 131 and a portion of the third conductive line 123, heating to solidify the silver paste, and obtaining the first conductor 51; and applying silver paste to the third pressing area 133 and a portion of the fourth conductive line 124, heating to solidify the silver paste, and obtaining the second conductor 52.

[0092] S9: Please see Figure 10 A fourth strain gauge 34 is disposed on a plurality of third bumps 23, a fifth strain gauge 35 is disposed on the fourth bumps 24, and a sixth strain gauge 36 is disposed between the fourth strain gauge 34 and the fifth strain gauge 35. Part of the sixth strain gauge 36 is disposed on the dielectric layer 11, and another part of the sixth strain gauge 36 is disposed on the side of the first conductor 51 or on the side of the second conductor 52. The sixth strain gauge 36 is electrically connected between the fourth strain gauge 34 and the fifth strain gauge 35 to obtain the pressure-sensitive circuit board 200.

[0093] In this embodiment, the manufacturing method of the pressure-sensitive circuit board 200 further includes:

[0094] S10: Please refer to Figure 12 A second solder resist layer 60 is provided above the fourth strain 34, the fifth strain 35 and the sixth strain 36.

[0095] Please see Figure 10The second embodiment of this application also provides a pressure-sensitive circuit board 200, which includes a dielectric layer 11, a third conductive line 123, a fourth conductive line 124, a plurality of first conductors 51, a plurality of second conductors 52, a fourth strain gauge 34, a fifth strain gauge 35, and a sixth strain gauge 36. The third conductive line 123 and the fourth conductive line 124 are spaced apart on the dielectric layer 11, with a portion of the dielectric layer 11 exposed between the third conductive line 123 and the fourth conductive line 124. The first conductor 51 includes a first body 511 and a plurality of third bumps 23 protruding from the first body 511. The first body 511 is disposed on the third conductive line 123, and a third accommodating space C is formed between every two adjacent third bumps 23. The second conductor 52 includes a second body 521 and a fourth bump 24 protruding from the second body 521. The second body 521 is disposed on the fourth conductive line 124, and a fourth accommodating space D is formed between every two adjacent fourth bumps 24. The fourth strain gauge 34 is disposed on the third protrusion 23 to cover a plurality of the third accommodating spaces C, the fifth strain gauge 35 is disposed on the fourth protrusion 24 to cover a plurality of the fourth accommodating spaces D, the sixth strain gauge 36 is connected between the fourth strain gauge 34 and the fifth strain gauge 35, and a portion of the sixth strain gauge 36 is disposed on the medium layer 11 corresponding to the second pressing area 132.

[0096] In this embodiment, the third protrusion 23 and the first body 511 are coated and formed in one step, and the fourth protrusion 24 and the second body 521 are also coated and formed in one step, which is beneficial to forming the first conductor 51 and the second conductor 52 with uniform thickness.

[0097] Please see Figure 11Specifically, when using the pressure-sensitive circuit board 200, the third conductive line 123 and the fourth conductive line 124 are connected to an external circuit (not shown) to form a closed loop. When an external force is applied to the second pressing area 132, the sixth strain gauge 36 will generate a large deformation, while the fourth strain gauge 34 corresponding to the first pressing area 131 or the fifth strain gauge 35 corresponding to the third pressing area 133 will generate a smaller deformation. The deformed portion of the fourth strain gauge 34 fills the third accommodating space C, and the deformed portion of the fifth strain gauge 35 fills the fourth accommodating space D. At the same time, the resistance values ​​of the deformed fourth strain gauge 34, fifth strain gauge 35, and sixth strain gauge 36 will all increase, and the resistance change of the sixth strain gauge 36 with a larger deformation is greater than the resistance change of the fourth strain gauge 34 or the fifth strain gauge 35 with a smaller deformation. This change in resistance value is measured by the external circuit. Then, by applying different magnitudes of external force to the pressing area 13 multiple times, multiple different rates of resistance change can be obtained, thus establishing a one-to-one correspondence between the rate of resistance change and the magnitude of the external force. Please refer to [link to relevant documentation]. Figure 13 Based on this one-to-one correspondence and the actual measured rate of change of resistance, the magnitude of external force can be measured.

[0098] This application also provides a pressure sensor (not shown), which includes pressure-sensitive circuit boards 100 and 200 as described above, a measuring circuit (not shown), a processing chip (not shown), and a display. The pressure-sensitive circuit boards 100 and 200 are electrically connected to the measuring circuit, and the processing chip is electrically connected to the measuring circuit and the display. The measuring circuit is used to measure the actual resistance change rate of the first strain gauge 31, the second strain gauge 32, and the third strain gauge 33 in the pressure-sensitive circuit board 100, or to measure the actual resistance change rate of the fourth strain gauge 34, the fifth strain gauge 35, and the sixth strain gauge 36 in the pressure-sensitive circuit board 200. The measured resistance change rate is transmitted to the processing chip, which pre-stores a one-to-one correspondence between theoretical resistance change rates and the magnitude of external forces. Based on the one-to-one correspondence, the processing chip calculates the actual external force magnitude under the actual resistance change rate, and the display shows the value of the actual external force.

[0099] The above description is merely an optimized implementation of this application, and its application should not be limited to this specific implementation. Other modifications and alterations made by those skilled in the art based on the technical concept of this application should fall within the protection scope of this application.

Claims

1. A pressure-sensitive circuit board, characterized in that, The device includes a circuit board, a plurality of conductive bumps, and a strain gauge. The circuit board includes a dielectric layer and conductive lines disposed on the dielectric layer. The plurality of conductive bumps are spaced apart on the conductive lines, and there is an accommodating space between each two adjacent conductive bumps. The strain gauge is disposed on the plurality of conductive bumps and covers the accommodating space. The strain gauge is used to deform under the action of external force, and the accommodating space is used to accommodate at least a portion of the deformed strain gauge. The conductive line includes a first conductive line and a second conductive line spaced apart from the first conductive line, with a portion of the dielectric layer exposed between the first conductive line and the second conductive line; The conductive bumps include a plurality of first bumps and a plurality of second bumps, the plurality of first bumps being spaced apart on the first conductive line, the plurality of second bumps being spaced apart on the second conductive line, and the accommodating space including a first accommodating space formed between each two adjacent first bumps and a second accommodating space formed between each two adjacent second bumps. The strain gauge includes a first strain gauge, a second strain gauge, and a third strain gauge. The first strain gauge is disposed on the first bump to cover a plurality of first accommodating spaces. The second strain gauge is disposed on the second bump to cover a plurality of second accommodating spaces. The third strain gauge is disposed on the dielectric layer and connected to the first strain gauge and the second strain gauge.

2. The pressure-sensitive circuit board as described in claim 1, characterized in that, The conductive line includes a third conductive line and a fourth conductive line spaced apart from the third conductive line, and a portion of the dielectric layer is exposed between the third conductive line and the fourth conductive line; The conductive bump includes a first conductor and a second conductor. The first conductor includes a first body portion and a plurality of third bumps protruding from the first body portion. The second conductor includes a second body portion and a plurality of fourth bumps protruding from the second body portion. The first body portion is disposed on the third conductive line, and the second body portion is disposed on the fourth conductive line. The accommodating space also includes a third accommodating space formed between every two adjacent third bumps and a fourth accommodating space formed between every two adjacent fourth bumps. The strain gauge includes a fourth strain gauge, a fifth strain gauge, and a sixth strain gauge. The fourth strain gauge is disposed on the third protrusion to cover a plurality of the third accommodating spaces. The fifth strain gauge is disposed on the fourth protrusion to cover a plurality of the fourth accommodating spaces. A portion of the sixth strain gauge is disposed on the dielectric layer and connected to the fourth strain gauge and the fifth strain gauge.

3. The pressure-sensitive circuit board as described in claim 1, characterized in that, The distance between any two adjacent conductive bumps is 18 to 30 micrometers.

4. The pressure-sensitive circuit board as described in claim 1, characterized in that, The pressure-sensitive circuit board also includes a solder resist layer disposed on the strain.

5. The pressure-sensitive circuit board as described in claim 1, characterized in that, The strain gauge is made of a conductor and an adhesive. The conductor includes at least one of silver nanowires, silver nanopowder, and carbon powder. The adhesive includes at least one of polydimethylsiloxane and thermoplastic polyurethane.

6. The pressure-sensitive circuit board as described in claim 1, characterized in that, The conductive bumps are made of metal or a combination of metal powder and adhesive.

7. A pressure sensor, characterized in that, Includes the pressure-sensitive circuit board as described in any one of claims 1 to 6.

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