Vibration Sensors

Abstract

The present invention provides a vibration sensor. The vibration sensor includes a wiring board, a vibration pickup structure and a signal pickup assembly fixed on opposite sides of the wiring board, the vibration pickup structure includes a first vibration pickup structure to a third vibration pickup structure housed in a first vibration chamber to a third vibration chamber, each of which is independent of the other, the signal pickup assembly includes a first to a third MEMS microphone, the first vibration pickup structure includes a first vibrating membrane vibrating along a first axis, the second vibration pickup structure includes a second vibrating membrane vibrating along a second axis, and the third vibration pickup structure includes a third vibrating membrane vibrating along a third axis, the first axis to the third axis being perpendicular to each other. The vibration sensor can simultaneously pick up vibration signals in three directions, and convert the sensed vibration signals into electrical signals, effectively improving the sensitivity and bandwidth of the vibration sensor.

Description

[Technical field]

[0001] The present invention relates to the technical field of sensors, and more particularly to a vibration sensor that converts a vibration signal into an electrical signal. [Background technology]

[0002] Vibration sensors are used to convert vibration signals into electrical signals and are widely used in the automotive field. In-vehicle active noise reduction technology uses a vibration sensor to pick up the vehicle body vibration signal, performs inversion in the circuit, and then plays it back inside the vehicle through the horn to cancel out the noise transmitted from the outside into the vehicle, thus improving the driving experience.

[0003] In the related art, vibration signals are generally picked up by accelerometers. Although accelerometers can accurately measure stable acceleration signals, active noise reduction processing is only interested in changing signals and not the absolute value of acceleration. In addition, accelerometers generally have difficulty in high-speed response, limited bandwidth, and relatively expensive prices. In addition to accelerometers, the related art also uses vibration pickup structures to convert vibration signals into changing pressures and then pick them up by microphones, but the normal vibration pickup structures can only pick up vibration signals in one direction. It can be used as a vibration trigger, but cannot be applied to active noise reduction. Furthermore, since only pressure changes in one chamber can be used, the sensitivity is low and the bandwidth is narrow.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide a new vibration sensor. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a vibration sensor that has high sensitivity and wider bandwidth. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a vibration sensor, the vibration sensor including a wiring board, and a vibration pickup structure and a signal pickup assembly fixed respectively to opposite sides of the wiring board; The vibration pickup structure includes a first vibration chamber, a second vibration chamber, and a third vibration chamber, each of which is independent of the other two, and the vibration pickup structure further includes a first vibration pickup structure housed in the first vibration chamber, a second vibration pickup structure housed in the second vibration chamber, and a third vibration pickup structure housed in the third vibration chamber; the signal pickup assembly includes a first MEMS microphone corresponding to the first vibration chamber, a second MEMS microphone corresponding to the second vibration chamber, and a third MEMS microphone corresponding to the third vibration chamber; the wiring board is provided with a first through hole communicating the first vibration chamber with the first MEMS microphone, a second through hole communicating the second vibration chamber with the second MEMS microphone, and a third through hole communicating the third vibration chamber with the third MEMS microphone; The first vibration pickup structure includes a first vibrating membrane vibrating along a first axis within the first vibration chamber, the second vibration pickup structure includes a second vibrating membrane vibrating along a second axis within the second vibration chamber, and the third vibration pickup structure includes a third vibrating membrane vibrating along a third axis within the third vibration chamber, the first axis, the second axis, and the third axis being perpendicular to each other.

[0007] Preferably, the first vibration pickup structure further includes a first vibrating bar fixed to the first vibrating membrane, the first vibrating bar including a fixed end fixed to the wiring board and a free end extending from the fixed end into a first vibration chamber.

[0008] Preferably, the first vibration pickup structure further includes a first mass block fixed to a side of the first vibrating piece remote from the first vibrating membrane.

[0009] Preferably, the vibration pickup structure further includes a bracket fixed to the wiring board and an upper cover attached to the bracket, and the first vibration chamber, the second vibration chamber and the third vibration chamber are all formed by being surrounded by the upper cover and the bracket.

[0010] Preferably, the first vibrating membrane is fixed to the bracket and divides the first vibrating chamber into a first upper vibrating chamber and a first lower vibrating chamber which are independent of each other, and the first through hole includes a first upper communicating hole connecting the first upper vibrating chamber and the first MEMS microphone, and a first lower communicating hole communicating the first lower vibrating chamber and the first MEMS microphone.

[0011] Preferably, the first MEMS microphone includes a MEMS chip fixed to the wiring board and having a back chamber, and a housing fixed to the wiring board and covered above the MEMS chip, the MEMS chip, the wiring board and the housing are enclosed to form an inner chamber, the first upper communication hole communicates between the first upper vibration chamber and the inner chamber, and the first lower communication hole communicates between the first lower vibration chamber and the back chamber.

[0012] Preferably, the first through hole penetrates the wiring board along a first direction, the bracket includes a first end fixed to the wiring board and a second end away from the first end along the first direction, and a cross-sectional area of ​​the bracket perpendicular to the first direction gradually decreases from the first end to the second end.

[0013] Preferably, a first through hole is provided in the fixed end, penetrating it along the first direction and corresponding to and communicating with the first upper communicating hole, and the first through hole communicates the first upper vibration chamber with the first upper communicating hole and the inner chamber.

[0014] Preferably, a second through hole is provided in the bracket, penetrating it along the first direction and corresponding to and communicating with the first lower communicating hole, and the second through hole communicates the first lower vibration chamber with the first lower communicating hole and the back chamber.

[0015] Preferably, the upper cover includes an upper fixed portion fixed to the second end, a lower fixed portion fixed to the wiring board, and an intermediate connecting portion connecting the upper fixed portion and the lower fixed portion, and the intermediate connecting portion and the first vibrating membrane are arranged at a distance from each other along the first axis. Effect of the Invention

[0016] Compared with the related art, the vibration sensor according to the present invention includes a wiring board, a vibration pickup structure and a signal pickup assembly fixed to opposite sides of the wiring board, the vibration pickup structure includes a first vibration pickup structure accommodated in a first vibration chamber, a second vibration pickup structure accommodated in a second vibration chamber, and a third vibration pickup structure accommodated in a third vibration chamber, which are independent of each other. The signal pickup assembly includes a first MEMS microphone provided in correspondence with the first vibration chamber, a second MEMS microphone provided in correspondence with the second vibration chamber, and a third MEMS microphone provided in correspondence with the third vibration chamber. The wiring board is provided with a first through hole communicating the first vibration chamber with the first MEMS microphone, a second through hole communicating the second vibration chamber with the second MEMS microphone, and a third through hole communicating the third vibration chamber with the third MEMS microphone. The first vibration pickup structure includes a first vibrating membrane vibrating along a first axis, the second vibration pickup structure includes a second vibrating membrane vibrating along a second axis, and the third vibration pickup structure includes a third vibrating membrane vibrating along a third axis, the first axis, the second axis and the third axis being perpendicular to each other. With the above structural design, the vibration sensor can simultaneously pick up vibration signals in three directions, and convert the sensed vibration signals into electrical signals, effectively improving the sensitivity and bandwidth of the vibration sensor.

[0017] In order to more clearly describe the technical solutions in the embodiments of the present invention, the following briefly introduces drawings necessary for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can further obtain other drawings based on these drawings without requiring creative efforts. [Brief description of the drawings]

[0018] [Figure 1] 1 is a perspective view of a vibration sensor according to the present invention; [Diagram 2]FIG. 2 is an exploded perspective view of the vibration sensor according to the present invention. [Diagram 3] FIG. 2 is a perspective view of a vibration pickup structure in the vibration sensor of the present invention. [Figure 4] FIG. 2 is an exploded perspective view of a vibration pickup structure in the vibration sensor according to the present invention. [Diagram 5] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Figure 6] 1 is a perspective view of a vibration sensor according to the present invention; [Figure 7] FIG. 7 is a cross-sectional view taken along line BB in FIG. [Figure 8] FIG. 7 is a cross-sectional view taken along line CC in FIG. [Figure 9] 2 is a structural schematic diagram of a first MEMS microphone in the vibration sensor of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention.

[0020] As shown in Figures 1 to 9, the present invention provides a vibration sensor 100, which includes a wiring board 1, and a vibration pickup structure 2 and a signal pickup assembly 3 fixed respectively to opposite sides of the wiring board 1.

[0021] The vibration pickup structure 2 includes a bracket 21 fixed to the wiring board 1, an upper cover 22 attached to the bracket 21, and a first vibration pickup structure 23, a second vibration pickup structure 24 and a third vibration pickup structure 25 for picking up vibration signals. Specifically, the bracket 21 and the upper cover 22 surround each other to form a first vibration chamber 26, a second vibration chamber 27 and a third vibration chamber 28, each of which is independent of each other, and here, the first vibration pickup structure 23 is housed in the first vibration chamber 26, the second vibration pickup structure 24 is housed in the second vibration chamber 27, and the third vibration pickup structure 28 is housed in the third vibration chamber 26.

[0022] The signal pickup assembly 3 includes a first MEMS microphone 31 provided in correspondence with the first vibration chamber 26, a second MEMS microphone 32 provided in correspondence with the second vibration chamber 27, and a third MEMS microphone 33 provided in correspondence with the third vibration chamber 28. As can be understood, the specific structures of the first MEMS microphone 31, the second MEMS microphone 32, and the third MEMS microphone 33 may be the same or different as long as they can perform the function of picking up signals. In this embodiment, the first MEMS microphone The specific structures of the first MEMS microphone 31, the second MEMS microphone 32 and the third MEMS microphone 33 are the same, and the structure of the first MEMS microphone 31 will be described below. The first MEMS microphone 31 includes a MEMS chip 312 fixed to the wiring board 1 and having a back chamber 311, and a housing 313 fixed to the wiring board 1 and covered above the MEMS chip 312, the MEMS chip 312, the wiring board 1 and the housing 313 are surrounded to form an inner chamber 314, and the MEMS chip 312 is a capacitive MEMS chip. As can be understood, the first MEMS microphone 31 has sound holes corresponding to the back chamber 311 and the inner chamber 314, respectively, so that the pressure signal of the vibration pickup structure 2 is transmitted to the signal pickup assembly 3.

[0023] In order to transmit the vibration signal picked up by the vibration pickup structure 2 to the signal pickup assembly 3, the wiring board 1 is provided with a first through hole 11 communicating the first vibration chamber 26 with the first MEMS microphone 31, a second through hole 12 communicating the second vibration chamber 27 with the second MEMS microphone 32, and a third through hole 13 communicating the third vibration chamber 28 with the third MEMS microphone 33. The first through hole 11, the second through hole 12, and the third through hole 13 all pass through the wiring board 1 along a first direction D.

[0024] Specifically, the first vibration pickup structure 23 includes a first vibrating membrane 231 capable of vibrating along a first axis X in the first vibrating chamber 26 and a first vibrating piece 232 fixed to the first vibrating membrane 231, the second vibration pickup structure 24 includes a second vibrating membrane 241 capable of vibrating along a second axis Y in the second vibrating chamber 27 and a second vibrating piece 242 fixed to the second vibrating membrane 241, and the third vibration pickup structure 25 includes a third vibrating membrane 251 capable of vibrating along a third axis Z in the third vibrating chamber 28 and a third vibrating piece 253 fixed to the second vibrating membrane 251, and the first axis X, the second axis Y and the The first vibration pickup structure 23, the second vibration pickup structure 24 and the third vibration pickup structure 25 have the same structure, and in order to avoid redundant description, the first vibration pickup structure 23 and the first MEMS microphone 31 are combined below to further describe the operating principle of the vibration sensor 100 of the present invention.

[0025] As shown in Figures 7 to 9, the first vibrating membrane 231 is fixed to the bracket 21 and divides the first vibrating chamber 26 into a first upper vibrating chamber 261 and a first lower vibrating chamber 262 which are independent of each other, wherein the first through hole 11 includes a first upper communication hole 111 connecting the first upper vibrating chamber 261 and the first MEMS microphone 31, and a first lower communication hole 112 communicating the first lower vibrating chamber 262 and the first MEMS microphone 31, specifically, the first upper communication hole 111 communicates the first upper vibrating chamber 261 and the inner chamber 314, and the first lower communication hole 112 communicates the first lower vibrating chamber 262 and the back chamber 311. Furthermore, the first vibrating bar 232 includes a fixed end 2321 fixed to the wiring board 1 and a free end 2322 extending from the fixed end 2321 to the first vibrating chamber 26, and a first through hole 2323 is opened in the fixed end 2321, which penetrates it along a first direction D and corresponds to and communicates with the first upper communicating hole 111, and the first through hole 2323 communicates between the first upper vibrating chamber 261 and the first upper communicating hole 111 and the inner chamber 314. When the first vibration pickup structure 23 senses vibration due to external noise and the first vibrating membrane 231 vibrates along the first axis X, the free end 2322 of the first vibrating bar 232 is driven to vibrate together, causing periodic deformation of the first vibrating bar 232. The pressure in the first upper vibrating chamber 261 increases, and a positive pressure is applied to the inner chamber 314 of the first MEMS microphone 31 through the first through hole 2323 and the first upper connecting hole 111, i.e., to the lower surface of the MEMS chip 312. At the same time, the pressure in the first lower vibrating chamber 262 decreases, and a negative pressure is applied to the upper surface of the MEMS chip 312 through the first lower connecting hole 112. The MEMS chip 312 then converts the changed pressure signal into an electrical signal and outputs it. Since the area of ​​the first vibrating membrane 231 is much larger than the area of ​​the vibrating membrane in the MEMS chip 312, the first vibrating membrane 231 can drive the operation of the MEMS chip 312 with only a very small amplitude (typically an amplitude of 0.00002 nanometers to 2 nanometers).As can be understood, the operation principle of the second vibration pickup structure 24 and the third vibration pickup structure 25 is the same as that of the first vibration pickup structure 23, and the first vibration membrane 231 in the first vibration pickup structure 23, the second vibration membrane 241 in the second vibration pickup structure 24, and the third vibration membrane 251 in the third vibration pickup structure 25 vibrate along the first axis X, the second axis Y, and the third axis Z, which are perpendicular to each other, respectively, and can simultaneously pick up vibration signals in three directions, thereby utilizing the pressure changes in the three chambers of the first vibration chamber 26, the second vibration chamber 27, and the third vibration chamber 28, respectively, to effectively improve the sensitivity and bandwidth of the vibration sensor 100. In addition, when the vibration sensor 100 according to the present invention is applied to a vehicle-mounted scene, it not only realizes a PDM output that picks up three-axis vibration signals at low cost, but also has good compatibility with external audio processing chips and effectively realizes the noise reduction function. And the supply capacity of traditional MEMS microphone chips is sufficient, the process is mature, and there is no technology constraint.

[0026] Furthermore, the bracket 21 includes a first end 211 fixed to the wiring board 1 and a second end 212 away from the first end 211 along the first direction D, and the cross-sectional area of ​​the bracket 21 perpendicular to the first direction D gradually decreases from the first end 211 to the second end 212.

[0027] Further, the bracket 21 has a second through hole 213 that penetrates the bracket 21 along the first direction D and communicates with the first lower communication hole 112, and the second through hole 213 communicates the first lower vibration chamber 262 with the first lower communication hole 112 and the back chamber 311. That is, a pressure change in the first lower vibration chamber 262 is transmitted to the MEMS chip 312 via the second through hole 213 and the first lower communication hole 112 in order.

[0028] As can be seen, the upper cover 22 includes an upper fixing portion 221 fixed to the second end portion 212, a lower fixing portion 222 fixed to the wiring board 1, and an intermediate connecting portion 223 connecting the upper fixing portion 221 and the lower fixing portion 222, and as can be seen, the intermediate connecting portion 223 and the third vibrating membrane 251 are spaced apart along the third axis X. As can be seen, the intermediate connecting portion 223 and the first vibrating membrane 231 are spaced apart along the first axis X, the intermediate connecting portion 223 and the second vibrating membrane 241 are spaced apart along the second axis Y, and the fixed end 2321 of the first vibrating bar 232 is fixed between the wiring board 1 and the lower fixing portion 222. In order to further improve the sensitivity of the vibration sensor 100, the first vibration pickup structure 23 further includes a first mass block 233 fixed to the first vibrating membrane 231.

[0029] It should be noted that the specific structures and operating principles of the second vibration pickup structure 24 and the second MEMS microphone 32, and the third vibration pickup structure 25 and the third MEMS microphone 33 are the same as those of the first vibration pickup structure 23 and the first MEMS microphone 31, and the second through hole 12 and the third through hole 13 have the same structure and function as the first through hole 11, and they will not be described here repeatedly.

[0030] Compared with the related art, the vibration sensor according to the present invention includes a wiring board, and a vibration pickup structure and a signal pickup assembly fixed to opposite sides of the wiring board, the vibration pickup structure includes a first vibration pickup structure accommodated in a first vibration chamber, a second vibration pickup structure accommodated in a second vibration chamber, and a third vibration pickup structure accommodated in a third vibration chamber, which are independent of each other, and the signal pickup assembly includes a first MEMS microphone provided corresponding to the first vibration chamber, a second MEMS microphone provided corresponding to the second vibration chamber, and a third MEMS microphone provided corresponding to the third vibration chamber. and a third MEMS microphone mounted on the wiring board, the wiring board being provided with a first through hole communicating the first vibration chamber with the first MEMS microphone, a second through hole communicating the second vibration chamber with the second MEMS microphone, and a third through hole communicating the third vibration chamber with the third MEMS microphone, the first vibration pickup structure including a first vibrating membrane vibrating along a first axis, the second vibration pickup structure including a second vibrating membrane vibrating along a second axis, and the third vibration pickup structure including a third vibrating membrane vibrating along a third axis, the first axis, the second axis, and the third axis being perpendicular to each other. With the above structural design, the vibration sensor can simultaneously pick up vibration signals in three directions, and convert the sensed vibration signals into electrical signals, effectively improving the sensitivity and bandwidth of the vibration sensor.

[0031] The above is only an embodiment of the present invention, and various modifications may be made by those skilled in the art to which the present invention pertains without departing from the creative concept of the present invention, but it should be understood that all of these modifications fall within the scope of the present invention.

Claims

1. 1. A vibration sensor comprising a wiring board and a vibration pickup structure and a signal pickup assembly respectively secured to opposite sides of the wiring board, The vibration pickup structure includes a first vibration chamber, a second vibration chamber, and a third vibration chamber, each of which is independent of the other two, and the vibration pickup structure further includes a first vibration pickup structure housed in the first vibration chamber, a second vibration pickup structure housed in the second vibration chamber, and a third vibration pickup structure housed in the third vibration chamber; the signal pickup assembly includes a first MEMS microphone corresponding to the first vibration chamber, a second MEMS microphone corresponding to the second vibration chamber, and a third MEMS microphone corresponding to the third vibration chamber; the wiring board is provided with a first through hole communicating the first vibration chamber with the first MEMS microphone, a second through hole communicating the second vibration chamber with the second MEMS microphone, and a third through hole communicating the third vibration chamber with the third MEMS microphone; the first vibration pickup structure includes a first vibrating membrane vibrating along a first axis within the first vibration chamber, the second vibration pickup structure includes a second vibrating membrane vibrating along a second axis within the second vibration chamber, and the third vibration pickup structure includes a third vibrating membrane vibrating along a third axis within the third vibration chamber, the first axis, the second axis, and the third axis being perpendicular to each other; The vibration pickup structure further includes a bracket fixed to the wiring board and an upper cover attached to the bracket, and the first vibration chamber, the second vibration chamber and the third vibration chamber are all formed by being surrounded by the upper cover and the bracket.

2. 2. The vibration sensor of claim 1, wherein the first vibration pickup structure further includes a first vibrating piece fixed to the first vibrating membrane, the first vibrating piece including a fixed end fixed to the wiring board and a free end extending from the fixed end into the first vibration chamber.

3. 3. The vibration sensor according to claim 2, wherein the first vibration pickup structure further comprises a first mass block fixed to a side of the first vibrating element remote from the first vibrating membrane.

4. The vibration sensor described in claim 1, characterized in that the first vibrating membrane is fixed to the bracket and divides the first vibration chamber into a first upper vibration chamber and a first lower vibration chamber that are independent of each other, and the first through hole includes a first upper communication hole connecting the first upper vibration chamber and the first MEMS microphone, and a first lower communication hole communicating the first lower vibration chamber and the first MEMS microphone.

5. The vibration sensor described in claim 4, characterized in that the first MEMS microphone includes a MEMS chip fixed to the wiring board and having a back chamber, and a housing fixed to the wiring board and covered above the MEMS chip, the MEMS chip, the wiring board and the housing are surrounded to form an inner chamber, the first upper communication hole connects the first upper vibration chamber to the inner chamber, and the first lower communication hole connects the first lower vibration chamber to the back chamber.

6. 6. The vibration sensor of claim 5, wherein the first through hole penetrates the wiring board along a first direction, the bracket includes a first end fixed to the wiring board and a second end away from the first end along the first direction, and a cross-sectional area of ​​the bracket perpendicular to the first direction gradually decreases from the first end to the second end.

7. The vibration sensor described in claim 6, characterized in that a first through hole is opened in the fixed end, penetrating it along the first direction and corresponding to and communicating with the first upper communicating hole, and the first through hole communicates with the first upper vibration chamber with the first upper communicating hole and the inner chamber.

8. The vibration sensor described in claim 7, characterized in that the bracket has a second through hole that penetrates it along the first direction and corresponds to and communicates with the first lower communication hole, and the second through hole communicates with the first lower vibration chamber, the first lower communication hole, and the back chamber.

9. The vibration sensor described in claim 8, characterized in that the upper cover includes an upper fixed portion fixed to the second end, a lower fixed portion fixed to the wiring board, and an intermediate connecting portion connecting the upper fixed portion and the lower fixed portion, and the intermediate connecting portion and the first vibrating membrane are arranged at a distance from each other along the first axis.

Images