Broadband sound vibration velocity measurement silk screen diaphragm structure

Abstract

The invention discloses a broadband sound vibration velocity measurement silk screen diaphragm structure, and belongs to the technical field of acoustic measurement. The broadband acoustic vibration velocity measurement silk screen diaphragm structure comprises a circular structure, a transverse supporting fiber structure and a radial supporting fiber structure, the circular structure is located at the center position, the transverse supporting fiber structure is a multi-ring nanofiber structure or a multi-ring regular polygon nanofiber structure concentric with the circular structure, and the radial supporting fiber structure is located in the radius direction and used for connecting the circular structure and the transverse supporting fiber structure. According to the broadband sound vibration velocity measurement silk screen diaphragm structure designed by the invention, the deformation is mainly influenced by the viscous force in a sound field, and the sound response sensitivity in the range from low frequency to medium-high frequency is consistent; a single structure has essential sound field directivity; in addition, the two-dimensional net structure is adopted, the high structural stability is achieved, and when one or more fiber structures in the net structure are damaged, the device can still work reliably.

Description

Technical Field

[0001] The invention discloses a broadband sound vibration velocity measurement screen diaphragm structure, belonging to the technical field of acoustic measurement. Background Art

[0002] Acoustic sensors are widely used in speech signals, industrial detection, military and defense industries. With the continuous expansion of acoustic application scenarios, the performance requirements for acoustic sensors in occasions such as speech enhancement, sound source localization, scene recording, and sound measurement in complex environments are gradually increasing. These occasions usually require filtering environmental noise and enhancing the acoustic characteristics of the target to be measured.

[0003] Currently common directional acoustic sensors mainly include:

[0004] First, the array structure is used to calculate the spatial sound field gradient information, but the size of this array is usually large, and the measurement sensitivity of the acoustic sensor in the low frequency band is low;

[0005] Second, use a co-oscillation type accelerometer to measure the acceleration information in the sound field, and obtain the vibration velocity information by integration; however, this solution is difficult to implement in an air environment.

[0006] The invention patent "An airborne sound particle velocity sensor and its manufacturing method" reports a method for detecting sound velocity based on measuring the change of resistance of adjacent thin wires with the sound field; a similar structure is reported in the paper "A thermal convection MEMS two-dimensional particle velocity sensor". However, this vibration velocity sensor requires heating of the sound sensitive device, which increases the power consumption of the device and limits its scope of use. The patent "Fiber Microphone" proposes a sound velocity sensor based on nano-conductive fibers, which places a one-dimensional conductive fiber in a magnetic field and controls the diameter and length of the conductive fiber so that its driving force is determined by the viscosity of the fluid. However, one-dimensional conductive fibers are easily damaged under the action of external forces, resulting in device failure. And the one-dimensional nanofiber structure is not suitable for the integration of optical detection means.

[0007] The diaphragm structure is the core component of the acoustic sensor. However, the driving force of the diaphragm structure currently used in acoustic signal detection mainly comes from the sound pressure signal to be measured, and it is usually an omnidirectional acoustic sensor. In order to achieve directivity and filter out environmental noise, it is necessary to place sensors at two different locations in space and measure the acoustic field gradient information by taking the difference. However, this structure will increase the overall size of the sensor system, and the detection sensitivity decreases rapidly as the frequency decreases. Summary of the invention

[0008] In view of the above problems, the present invention designs a wide-band acoustic velocity measurement silk screen diaphragm structure, the deformation of which is mainly affected by the viscosity in the sound field, and the acoustic response sensitivity is consistent in the range from low frequency (<0.1Hz) to medium and high frequency (>5kHz); and a single structure has inherent sound field directivity; in addition, it adopts a two-dimensional mesh structure with high structural stability. When one or more fiber structures in the mesh structure are damaged, the device can still work reliably.

[0009] The object of the present invention is achieved in that:

[0010] A wide-band sound velocity measurement wire mesh diaphragm structure comprises a circular structure, a transverse support fiber structure and a radial support fiber structure; the circular structure is located at the center, the transverse support fiber structure is a multi-circle nanofiber structure or a multi-circle regular polygonal nanofiber structure concentric with the circular structure, and the radial support fiber structure is located in the radial direction and is used to connect the circular structure and the transverse support fiber structure.

[0011] The above-mentioned wide-band acoustic velocity measurement wire mesh diaphragm structure also includes a wire mesh diaphragm supporting structure, which is located outside the transverse supporting fiber structure and connected to the radial supporting fiber structure, and is used to support the circular structure, the transverse supporting fiber structure and the radial supporting fiber structure.

[0012] The above broadband acoustic velocity measurement screen diaphragm structure, the circular structure, the lateral supporting fiber structure and the radial supporting fiber structure are made of the same material, are an integral nanofiber structure, and are synchronously manufactured by micro-nano processing technology.

[0013] In the above broadband acoustic velocity measurement screen diaphragm structure, the cross-section of the transverse supporting fiber structure is circular or rectangular, and the cross-section of the radial supporting fiber structure is circular or rectangular.

[0014] In the above broadband acoustic velocity measurement screen diaphragm structure, the number of the radial supporting fiber structures is 3-15 and they are evenly distributed along the circumferential direction.

[0015] The above broadband acoustic velocity measurement screen diaphragm structure, the circular structure, the lateral supporting fiber structure and the radial supporting fiber structure are made of PMMA, PI, PU, ​​PC, PET, graphene, gold, silver, copper, aluminum or carbon nanotubes.

[0016] When the circular structure, the lateral supporting fiber structure and the radial supporting fiber structure are made of non-metallic materials, a metal film structure with a thickness not exceeding 100 nm is deposited on the same surface of the circular structure, the lateral supporting fiber structure and the radial supporting fiber structure. The metal film structure is gold, silver, aluminum, copper or chromium, and its thickness is less than that of the circular structure, the lateral supporting fiber structure and the radial supporting fiber structure.

[0017] The material of the silk screen membrane support structure is silicon, quartz, metal, PMMA, PC, PET or PU.

[0018] Beneficial effects:

[0019] First, the deformation of the wire mesh diaphragm structure of the present invention is mainly affected by the viscosity in the sound field, and the acoustic response sensitivity is consistent in the range from low frequency (<0.1Hz) to medium and high frequency (>5kHz); and the single structure has the essential sound field directivity;

[0020] Second, the wire mesh membrane structure of the present invention is a two-dimensional mesh structure with high structural stability. When one or more fiber structures in the mesh structure are damaged, the device can still work reliably. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the first structure of the broadband sound velocity measurement screen diaphragm structure of the present invention;

[0022] Figure 2 A second structural schematic diagram of the broadband acoustic velocity measurement screen diaphragm structure of the present invention;

[0023] Figure 3 The simulation results of frequency response of PMMA cilia with different diameters;

[0024] Figure 4 This is the frequency response simulation result of the silk screen diaphragm.

[0025] In the figure: 1 circular structure, 2 transverse supporting fiber structure, 3 radial supporting fiber structure, 4 wire mesh diaphragm supporting structure. DETAILED DESCRIPTION

[0026] The specific implementation modes of the present invention will be further described in detail below with reference to the accompanying drawings. Specific implementation method 1

[0028] A broadband acoustic velocity measurement wire mesh diaphragm structure in this specific implementation includes a circular structure 1, a lateral support fiber structure 2, a radial support fiber structure 3 and a wire mesh diaphragm support structure 4; the circular structure 1 is located at the center, and the lateral support fiber structure 2 is a multi-ring nanofiber structure concentric with the circular structure 1, such as Figure 1 As shown, the radial supporting fiber structure 3 is located in the radial direction, and is used to connect the circular structure 1 and the transverse supporting fiber structure 2; the wire mesh membrane supporting structure 4 is located outside the transverse supporting fiber structure 2, and is connected to the radial supporting fiber structure 3, and is used to support the circular structure 1, the transverse supporting fiber structure 2 and the radial supporting fiber structure 3. Specific implementation method 2

[0030] A broadband acoustic velocity measurement wire mesh diaphragm structure in this specific implementation includes a circular structure 1, a lateral support fiber structure 2, a radial support fiber structure 3 and a wire mesh diaphragm support structure 4; the circular structure 1 is located at the center, and the lateral support fiber structure 2 is a multi-circle regular polygonal nanofiber structure concentric with the circular structure 1, such as Figure 2 As shown, the radial supporting fiber structure 3 is located in the radial direction, and is used to connect the circular structure 1 and the transverse supporting fiber structure 2; the wire mesh membrane supporting structure 4 is located outside the transverse supporting fiber structure 2, and is connected to the radial supporting fiber structure 3, and is used to support the circular structure 1, the transverse supporting fiber structure 2 and the radial supporting fiber structure 3. Specific implementation method three

[0032] A broadband acoustic velocity measurement screen diaphragm structure in this specific implementation manner further defines at least one of the following technical features on the basis of specific implementation manner one or specific implementation manner two:

[0033] The circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3 are made of the same material and are an integral nanofiber structure, which are simultaneously manufactured using micro-nano processing technology.

[0034] The cross-section of the transverse supporting fiber structure 2 is circular or rectangular, and the cross-section of the radial supporting fiber structure 3 is circular or rectangular.

[0035] The number of the radial supporting fiber structures 3 is 3-15 and they are evenly distributed along the circumferential direction.

[0036] The circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3 are made of PMMA, PI, PU, ​​PC, PET, graphene, gold, silver, copper, aluminum or carbon nanotubes.

[0037] When the circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3 are made of non-metallic materials, a metal film structure with a thickness not exceeding 100 nm is deposited on the same surface of the circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3. The metal film structure is gold, silver, aluminum, copper or chromium, and its thickness is less than that of the circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3.

[0038] The material of the wire mesh diaphragm support structure 4 is silicon, quartz, metal, PMMA, PC, PET or PU. Specific implementation method four

[0040] A broadband acoustic velocity measurement screen diaphragm structure in this specific implementation further defines the following dimensional technical features based on the specific implementation method three:

[0041] The thickness of the circular structure 1, the lateral supporting fiber structure 2 and the radial supporting fiber structure 3 does not exceed 5 microns;

[0042] The diameter of the circular structure 1 is not more than 1 mm and not less than 100 micrometers;

[0043] If the cross section of the lateral supporting fiber structure 2 is a circular structure, the diameter ranges from 0.5 micrometers to 20 micrometers; if it is a rectangle, the length and width of the rectangle are both within the range of 0.5 micrometers to 20 micrometers;

[0044] The lateral supporting fiber structure 2 is a multi-ring nanofiber structure, the minimum radius of which is 100 microns greater than the radius of the circular structure 1; and the minimum radius of which is 100 microns less than the radius of the wire mesh membrane supporting structure 4;

[0045] The multi-circle structure of the transverse supporting fiber structure 2 is evenly spaced from the circular structure 1 to the wire mesh membrane supporting structure 4, and the radial spacing between two adjacent circles is not less than 100 microns and not more than 1 mm;

[0046] If the cross section of the radial support fiber structure 3 is a circular structure, the diameter ranges from 0.5 micrometers to 20 micrometers; if it is a rectangle, the length and width of the rectangle are both within the range of 0.5 micrometers to 20 micrometers;

[0047] The thickness of the silk screen membrane support structure 4 is not less than 100 microns, and the diameter of the inner middle hollow part is not less than 1 mm and not more than 10 mm. Specific implementation method five

[0049] A broadband sound velocity measurement screen diaphragm structure under this specific implementation is simplified in performance analysis based on the second specific implementation, and the broadband sound velocity measurement screen diaphragm structure is decomposed into a series of cilia combinations.

[0050] First, the force equation of cilia in the flow field is established. Assuming that the radius of cilia is r and the length is L, it is subject to the Euler-Bernoulli bending, axial tension and fluid force of the surrounding medium. The force equation is expressed as follows:

[0051]

[0052] When r is relatively small, the main force acting on the ciliary motion is proportional to v(t), that is, the relative motion of the ciliary mass with the surrounding medium. So we get:

[0053]

[0054] The above equation shows that when the cilia are thin enough, they will flow with the fluid. Therefore, the movement of cilia can well represent the movement of the medium around them.

[0055] The one-dimensional ciliary motion equation is used for simulation analysis to obtain the transmission efficiency of ciliary structures with different diameters. The results are as follows: Figure 3 As shown, Figure a is 0.5 μm and Figure b is 1 μm; the results show that when the diameter of the cilia is small enough, high-fidelity extraction of the vibration of the surrounding fluid medium can be achieved, thereby achieving high-sensitivity perception of acoustic signals, especially low-frequency acoustic signals.

[0056] PMMA was selected as the mesh material, the overall diameter of the model was 10 mm, and the line width of the cilia was 2 μm. The mesh model was simulated at a frequency of 1 Hz to 10,000 Hz, and the frequency response of the mesh when a plane acoustic wave with an intensity of 1 Pa was applied to the mesh diaphragm was analyzed. Figure 4 As shown. Figure 4 It can be found that the velocity transfer ratio of the mesh diaphragm in a wider frequency range (especially low frequency) is 1, that is, Vsilk / Vair≈1, which means that low-frequency sound information can be acquired with high fidelity.

Claims

1. A broadband acoustic velocity measurement screen diaphragm structure, characterized in that: The invention comprises a circular structure (1), a transverse supporting fiber structure (2) and a radial supporting fiber structure (3); the circular structure (1) is located at the center, the transverse supporting fiber structure (2) is a multi-circle nanofiber structure or a multi-circle regular polygonal nanofiber structure concentric with the circular structure (1), and the radial supporting fiber structure (3) is located in the radial direction and is used to connect the circular structure (1) and the transverse supporting fiber structure (2).

2. A broadband acoustic velocity measurement screen diaphragm structure according to claim 1, characterized in that: It also includes a wire mesh diaphragm support structure (4), which is located outside the transverse supporting fiber structure (2) and connected to the radial supporting fiber structure (3), and is used to support the circular structure (1), the transverse supporting fiber structure (2) and the radial supporting fiber structure (3).

3. A broadband sound velocity measurement screen diaphragm structure according to claim 1 or 2, characterized in that: The circular structure (1), the transverse supporting fiber structure (2) and the radial supporting fiber structure (3) are made of the same material and are an integral nanofiber structure, which are simultaneously manufactured using micro-nano processing technology.

4. A broadband sound velocity measurement screen diaphragm structure according to claim 1 or 2, characterized in that: The cross-section of the transverse supporting fiber structure (2) is circular or rectangular, and the cross-section of the radial supporting fiber structure (3) is circular or rectangular.

5. A broadband acoustic velocity measurement screen diaphragm structure according to claim 1 or 2, characterized in that: The number of the radial supporting fiber structures (3) is 3-15 and they are evenly distributed along the circumferential direction.

6. A broadband sound velocity measurement screen diaphragm structure according to claim 1 or 2, characterized in that: The circular structure (1), the lateral supporting fiber structure (2) and the radial supporting fiber structure (3) are made of PMMA, PI, PU, ​​PC, PET, graphene, gold, silver, copper, aluminum or carbon nanotubes.

7. A broadband acoustic velocity measurement screen diaphragm structure according to claim 6, characterized in that: When the circular structure (1), the transverse supporting fiber structure (2) and the radial supporting fiber structure (3) are made of non-metallic materials, a metal film structure with a thickness not exceeding 100 nm is deposited on the same surface of the circular structure (1), the transverse supporting fiber structure (2) and the radial supporting fiber structure (3), wherein the metal film structure is made of gold, silver, aluminum, copper or chromium, and the thickness is less than the thickness of the circular structure (1), the transverse supporting fiber structure (2) and the radial supporting fiber structure (3).

8. A broadband acoustic velocity measurement screen diaphragm structure according to claim 2, characterized in that: The material of the silk screen membrane support structure (4) is silicon, quartz, metal, PMMA, PC, PET or PU.

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