CN113810823A - Frequency response adjustable miniature sound pressure amplification structure - Google Patents
Frequency response adjustable miniature sound pressure amplification structure Download PDFInfo
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- H—ELECTRICITY
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- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
- H04R1/28—Transducer mountings or enclosures modified by provision of mechanical or acoustic impedances, e.g. resonator, damping means
- H04R1/2807—Enclosures comprising vibrating or resonating arrangements
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- H—ELECTRICITY
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- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
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- H04R2460/00—Details of hearing devices, i.e. of ear- or headphones covered by H04R1/10 or H04R5/033 but not provided for in any of their subgroups, or of hearing aids covered by H04R25/00 but not provided for in any of its subgroups
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Abstract
The invention provides a frequency response adjustable miniature sound pressure amplification structure which comprises a shell (1), a plurality of primary sensitive membranes (2), a plurality of connecting rods (3), a plurality of secondary sensitive membranes (4) and a terminal sensitive membrane (5), wherein the shell is of a rigid structure and comprises two cavity structures; a plurality of primary sensitive films are used as receiving ends of sound pressure signals and fixed on the upper surface frame of the shell (1) to form a first boundary condition of peripheral fixed support; the connecting rods are respectively connected with the centers of the first-stage sensitive membranes and the second-stage sensitive membranes, so that the first-stage sensitive membranes and the second-stage sensitive membranes move together under the action of sound pressure; the plurality of first-stage sensitive membranes, the plurality of second-stage sensitive membranes and the shell form a first sealed cavity together; the plurality of secondary sensitive films are fixed on a frame in the shell to form a second boundary condition of peripheral fixed support, and form a second sealed cavity together with the terminal sensitive film and the shell; the terminal sensitive film is used as an amplification end of the sound pressure signal and fixed on the lower surface of the shell to form a third boundary condition of peripheral fixed support.
Description
Technical Field
The invention relates to the technical field of sound pressure sensing, in particular to a frequency response adjustable miniature sound pressure amplification structure.
Background
With the rapid advance of information technology, high-sensitivity weak acoustic signal detection has become a key research point at home and abroad. In recent years, the focus of research on sound pressure sensors has also been on the development of an optical fiber type sound pressure sensing technology from an electroacoustic sensing technology. For example, the optical fiber type sound pressure sensor is a kind of sound sensor using optical fiber as light transmission medium or detection unit, and compared with the traditional electroacoustic sensor, the optical fiber type sound pressure sensor has the advantages of high sensitivity, wide frequency band response, electromagnetic interference resistance and the like, and can be widely applied to the fields of national defense safety, industrial nondestructive detection, medical diagnosis, consumer electronics and the like.
Aiming at different frequency detection ranges, the sensitive structure of the optical fiber sound pressure sensor can be divided into a plane diaphragm type and a beam type. The pressure-sensitive unit of the planar diaphragm type sound pressure sensor is generally a single circular peripheral clamped film, works in a range far lower than first-order natural frequency, has relatively flat response to a wider frequency range, and is lower in sensitivity. The sensitive unit of the beam structure sound pressure sensor is generally a cantilever beam with one end fixedly supported, only works near a first-order natural frequency, and has higher sensitivity but narrower bandwidth. Beam structures are used in many specific applications, such as a 75 μm by 50 μm by 8 μm cantilever beam acoustic pressure sensor made of silicon dioxide, which is used for endoscopic photoacoustic imaging, and has an operating frequency of 0.74MHz (J.Liu, et al, Micro-cantilever-based optical phosphor hybrid by a femto-optical laser, optics Letters,2017,42(13): 2459.). In contrast, the flat-panel chip type optical fiber sound pressure sensor has wider application in daily life. At present, the main mode for improving the sensitivity of the planar diaphragm type sound pressure sensor is to change a pressure-sensitive material or optimize the structural size of the pressure-sensitive material. Most of the current sensitive materials are silicon films, the thickness of the silicon films is micron-sized, but the maximum load value of the silicon films is small, and the silicon films are easy to break. The thickness of the graphene film can reach the nanometer level, is one thousand times of that of a silicon film, the overload resistance of the graphene film exceeds the silicon film with the same thickness, the graphene film can be used for a pressure-sensitive film, but the sound pressure sensitivity of the graphene film is closely related to the self performance of the film material, and the preparation and substrate suspension transfer methods of the graphene film with large area, high quality and uniform thickness are not mature, so that the performance of a sound pressure sensor based on the graphene film is influenced. Although graphene fiber acoustic pressure sensors in the published literature can achieve voltage sensitivity (c.li., actual, Analyzing the application of small-high sensitivity hybrid-Perot acoustic sensors using a nano-sound diaphragm Science and Technology,2015,26: 085101) substantially equivalent to that of current commercial circular condenser diaphragm microphones (-50 mV/Pa), there is a gap for remote acoustic signal detection. Human beings have a wider dynamic audible sound pressure range (0-140dB, wherein the 0dB reference pressure is 20 mu Pa), and can effectively receive sound pressure in the frequency range of 20Hz-20kHz, which is closely related to the unique physiological structure of human ears. In particular, j.h.han et al, 2018, inspired by cochlear Basilar membrane, manufactured a multi-frequency tunable multi-channel piezoelectric acoustic sensor in the range of 100Hz-4 kHz based on a piezoelectric PZT film, obtained sound pressure sensitivity superior to that of a conventional commercial diaphragm microphone (g.r.a.s. capacitive reference microphone), used for voice recognition for human-computer interaction (h.s.lee, et al, Flexible inorganic piezoelectric transducer acoustic sensors for biological interactive acoustic signals, ad.v.functional.mater.2014, (24) (44):6914-, and j.h.han, et al, basic-embedded selected-powered acoustic sensor acoustic signals, and configured with multichannel array probes 198, and 198, more complex acquisition hardware is required, and 198, more complex acquisition hardware is required for parallel processing with the multichannel piezoelectric acoustic sensors. Some documents have designed a Helmholtz resonator for fiber optic acoustic sensors that has multiple resonant frequencies that can be resonantly amplified at 14 frequency points, where sensitivity can be increased by a factor of 2.11 at 120Hz (r.gao, axial. sensitivity enhancement sensor through acoustic resonance estimation, optical, 2018: S0030402618306594), but since each resonant frequency bandwidth is extremely narrow, less than 100Hz, the overall frequency response of the sensor is extremely uneven.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: aiming at the existing single sensor probe, by referring to the unique physiological structure and the sound pressure amplification characteristic of human ears, a sound pressure amplification structure with adjustable frequency response is designed, and the amplification sensitivity enhancement of sound pressure in an adjustable frequency range is realized through the matching connection with a sound pressure sensor, so that the sound pressure sensitivity of the sound pressure amplification structure is effectively improved in a wider and adjustable frequency range, and the sound pressure amplification structure has important practical significance and application value for realizing the high sensitivity of the sound pressure sensor.
The invention aims to provide a frequency-response-adjustable miniature sound pressure amplification structure which comprises a shell (1), a plurality of primary sensitive membranes (2), a plurality of connecting rods (3), a plurality of secondary sensitive membranes (4) and a terminal sensitive membrane (5), wherein the shell (1) is a rigid structure and comprises two cavity structures; a plurality of first-stage sensitive membranes (2) serving as receiving ends of sound pressure signals are fixed on the upper surface frame of the shell (1) to form a first boundary condition of peripheral fixed support; the connecting rods (3) are respectively connected with the centers of the primary sensitive membranes (2) and the secondary sensitive membranes (4) to enable the primary sensitive membranes and the secondary sensitive membranes to move together under the action of sound pressure; a plurality of the primary sensitive films (2), a plurality of the secondary sensitive films (4) and the shell (1) form a first sealed cavity together; the secondary sensitive films (4) are fixed on a frame in the shell (1) to form a second boundary condition of peripheral solid support, and form a second sealed cavity together with the terminal sensitive film (5) and the shell (1); the terminal sensitive film (5) is used as an amplification end of a sound pressure signal and fixed on the lower surface of the shell (1) to form a third boundary condition of peripheral fixing.
Preferably, the volume of the first sealed cavity is larger than that of the second sealed cavity, and air or inert gas is sealed in the first sealed cavity and the second sealed cavity.
Preferably, the shell (1) and the plurality of connecting rods (3) are made of rigid materials, and deformation under the action of sound pressure is negligible; the connecting rods (3) are made of low-density materials, so that the pre-deformation of the thin film caused by the mass of the connecting rods is negligible.
Preferably, the plurality of first-stage sensitive membranes (2), the plurality of second-stage sensitive membranes (4) and the terminal sensitive membrane (5) are in a peripheral clamped thin film structure and have regular shapes, such as square and round. Of course, one skilled in the art can design other suitable near-regular shapes as desired; the plurality of the first-stage sensitive membranes (2) or the plurality of the second-stage sensitive membranes (4) have a plurality of different membrane thicknesses or have a plurality of different thin-film materials.
Preferably, the number of the first-stage sensitive membranes (2) is equal to that of the second-stage sensitive membranes (4), the first-stage sensitive membranes and the second-stage sensitive membranes are in one-to-one correspondence, the first-stage sensitive membranes and the second-stage sensitive membranes are correspondingly connected through the connecting rods (3), the side lengths of the first-stage sensitive membranes (2) and the side lengths of the second-stage sensitive membranes (4) are the same, the first-stage sensitive membranes (2) are the same in shape and size and are distributed in a centrosymmetric manner, the connecting rods (3) are the same in shape and size and are distributed in a centrosymmetric manner, and the second-stage sensitive membranes (4) are the same in shape and size and are distributed in a centrosymmetric manner.
Preferably, the plurality of connecting rods (3) connect the plurality of first-stage sensitive membranes (2) and the plurality of second-stage sensitive membranes (4) at the central positions, and are in a structure with a wide top and a narrow bottom, so that the contact area between the connecting rods (3) and the plurality of first-stage sensitive membranes (2) is larger than that between the connecting rods (3) and the plurality of second-stage sensitive membranes (4).
Preferably, the areas of the plurality of primary sensitive films (2), the plurality of secondary sensitive films (4) and the terminal sensitive film (5) are sequentially reduced, and an elastic film sensitive to sound pressure is used.
Preferably, the housing (1) is fixed with a plurality of the primary sensitive membranes (2), a plurality of the secondary sensitive membranes (4) and the terminal sensitive membrane (5) through physical adsorption, chemical adsorption or bonding; the connecting rods (3) are respectively fixed with the primary sensitive membranes (2) and the secondary sensitive membranes (4) through bonding.
Preferably, the optical fiber ferrule also comprises an optical fiber ferrule (6), and the terminal sensitive membrane (5) is adsorbed on the surface of the optical fiber ferrule (6); and then the optical fiber ceramic ferrule (6) is adhered to the bottom of the shell (1) by epoxy resin adhesive, no gap is left at the adhered part, and the optical fiber ceramic ferrule (6) is arranged as a part of the shell (1).
Preferably, the frequency response adjustable miniature sound pressure amplification structure is realized through 3D printing integrated into one piece, separation component adhesion and MEMS technology.
The working principle is as follows: the deflection change of the terminal sensitive film (5) in the structure realizes the detection of the signal amplified by sound pressure in an optical fiber or electrical measurement mode. And the frequency response adjustable miniature sound pressure amplification structure can be matched and connected with the sound pressure sensor probe by virtue of the sealed connector, so that the amplification sensitivity enhancement of the sound pressure signal is realized, and the frequency response is adjustable.
The frequency response adjustable miniature sound pressure amplifying structure of the invention has the following working process: the interior of the sound pressure amplification structure with adjustable initial frequency response is in a sealed state; when external sound pressure acts on the plurality of primary sensitive membranes 2, the primary sensitive membranes 2 are deformed, and the sound pressure acting on the surfaces of the primary sensitive membranes 2 is amplified respectively through the plurality of connecting rods 3 and is transmitted to the plurality of secondary sensitive membranes 4; because the plurality of secondary sensitive films 4 and the terminal sensitive film 5 form a sealed cavity, the secondary sensitive film is deformed under the action of the connecting rod, so that the pressure change of the sealed cavity is caused and acts on the terminal sensitive film, and the sound pressure sensed by the terminal sensitive film 5 is amplified; in addition, the plurality of first-order sensitive membranes 2 and the plurality of second-order sensitive membranes 4 have different membrane thicknesses or different thin-film materials, so that the whole structure has a plurality of different first-order natural frequencies, a proper membrane thickness is selected and a proper material is selected, the plurality of first-order natural frequencies cover a wider frequency range, the intervals are equidistant, the frequency response of the whole structure is the frequency response envelopes of n single structures, and the sound pressure resonance amplification effect is high in the range from the 1 st first-order natural frequency to the nth first-order natural frequency. In the range lower than the 1 st first-order natural frequency, the sound pressure gain based on the auditory bone sound transmission principle of the human ear can also realize the sound pressure amplification in the lower frequency range. According to the invention, the sound pressure is amplified by adopting the multi-stage membrane structure, the frequency response is adjusted by adopting the multi-stage membrane structures, and the frequency response simulation is carried out on the embodiment in the figure 1, so that the frequency response simulation result shown in figure 5 is obtained, the sound pressure sensitivity is obviously improved by amplifying the sound pressure by the multi-stage membrane structures, and after four multi-stage membrane structures are used, the sound pressure sensitivity is higher in a wider frequency range than that of a single membrane structure, the number of the multi-stage membrane structures is changed, and the thickness of each one-stage sensitive membrane is changed, so that the sensitivity can be enhanced in the wider frequency range or a specific frequency range, and the effect of adjusting the frequency is achieved. The amplified sound pressure signal can obtain the change of the central deflection of the terminal sensitive film in an optical fiber detection or electrical detection mode, so that the measurement of the sound pressure to be measured is realized.
Compared with the prior art, the invention has obvious advantages and beneficial effects. By means of the technical scheme, the structure provided by the invention can obtain remarkable technical progress and practicability, has wide industrial utilization value and at least has the following advantages:
(1) the structure of the invention has wide application range, can be matched and connected with the diaphragm type sound pressure sensor, only needs single-channel detection, and has simple subsequent signal processing.
(2) The invention realizes the transmission and amplification of sound pressure based on the auditory bone sound transmission principle of human ears, has flat sound pressure amplification effect on sound signals with lower frequency, and has very high sound pressure resonance amplification effect on the range covered by a plurality of adjustable first-order natural frequencies.
(3) The invention has the advantages that the adjustment of the frequency response is related to the film thickness and material parameters of the first-stage sensitive film and the second-stage sensitive film, the self-defined design of a plurality of first-stage natural frequencies can be realized by changing the film thickness and selecting different film materials, and the size and the distance of the plurality of natural frequencies are changed, so that the frequency response adjustment is realized.
(4) The invention can realize different sound pressure amplification factors by changing the structure size of each part.
(5) The invention has the advantages of wide material selection range, low process requirement and relatively simple manufacturing method. The shell and the connecting rod can be made of common resin, plastic, metal and the like, and are not limited to a single material; the shell can be spliced in multiple parts; the first-stage sensitive membrane and the second-stage sensitive membrane can use common elastic membranes and the like.
(6) The invention contains two sealed cavities, which provides conditions for generating pressure difference, but the sealed cavity has low requirement on air tightness, the general manufacturing process can be realized, and the pressure intensity in the cavity has no special requirement.
(7) The deflection change of the terminal sensitive film can realize detection on the signal amplified by sound pressure in an optical fiber or electrical measurement mode, and has the advantage of wide application range.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.
Drawings
Some specific embodiments of the invention will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. The objects and features of the present invention will become more apparent in view of the following description taken in conjunction with the accompanying drawings, in which:
fig. 1 is a schematic structural diagram of a frequency response adjustable micro sound pressure amplifying structure according to an embodiment of the present invention.
Fig. 2 is a schematic structural view of a housing of the frequency response adjustable micro sound pressure amplifying structure according to the embodiment of the invention after perspective.
Fig. 3 is a cross-sectional view of two different positions of a frequency response adjustable micro sound pressure amplifying structure according to an embodiment of the present invention.
Fig. 4 is a schematic view of a frequency response adjustable micro sound pressure amplification structure connected with an optical fiber ferrule according to an embodiment of the invention.
Fig. 5 is a diagram illustrating simulation effects of the frequency response adjustable micro sound pressure amplifying structure on sound pressure amplification and frequency response improvement according to the embodiment of the invention.
The reference numbers in the figures mean: the optical fiber sensing module comprises a shell 1, a primary sensitive membrane 2, a connecting rod 3, a secondary sensitive membrane 4, a terminal sensitive membrane 5 and an optical fiber ceramic ferrule 6.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined purpose, the following detailed description of the embodiments, methods, steps and effects of the system for generating official documents of the government organization and the method for generating official documents of the government organization according to the present invention are provided with the accompanying drawings and the preferred embodiments.
While the present invention has been described in connection with the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications, equivalent arrangements, and specific embodiments thereof.
As shown in fig. 1, 2, and 3, the sound pressure amplifying structure with adjustable frequency response of the present embodiment mainly includes a housing 1, four primary sensitive membranes 2, four connecting rods 3, four secondary sensitive membranes 4, and a terminal sensitive membrane 5. In the embodiment, the shell 1 and the connecting rod 3 are made of photosensitive resin; the first-stage sensitive film 2 adopts a copper film, and the second-stage sensitive film 4 adopts a TPU (thermoplastic polyurethane) film; the terminal sensitive film is a graphene film. Manufacturing a shell 1 and a connecting rod 3 by using a 3D printing mode; cutting a copper film used by the first-stage sensitive film 2 to cover a square frame on the upper surface of the shell 1, and cutting a TPU film used by the second-stage sensitive film 4 to cover a smaller square frame in the shell 1; the second-level sensitive film 4 of epoxy resin glue is pasted inside the shell 1, and no gap is left at the periphery of the pasting position; respectively sticking one sides of the wide surfaces of the four connecting rods 3 to the centers of the four primary sensitive films 2 by using epoxy resin glue; epoxy resin glue is uniformly coated on the top of the shell 1 and one side of the narrow surfaces of the four connecting rods 3, the primary sensitive membrane 2 and the connecting rods 3 are integrally adhered to the shell 1, no gap exists at the adhering position of the primary sensitive membrane 2 and the shell 1, and one side of the narrow surface of the connecting rods 3 is adhered to the center of the secondary sensitive membrane 4; the terminal sensitive film 5 is a commercial graphene film. As the printed shell 1 is made of photosensitive resin material, the two can not be directly adhered or adsorbed, and therefore, as shown in fig. 4, the terminal sensitive membrane 5 is adsorbed on the surface of the optical fiber ceramic ferrule 6 by the optical fiber ceramic ferrule 6; and then the optical fiber ceramic ferrule 6 is stuck to the bottom of the shell 1 by epoxy resin glue, and no gap exists at the stuck part, so that the optical fiber ceramic ferrule 6 also belongs to one part of the shell 1. After the first-stage sensitive film 2 senses the sound pressure, the second-stage sensitive film 4 is driven to vibrate, the pressure of the second sealed cavity is changed, and the changed pressure acts on the terminal sensitive film 5 to generate deflection change. The deflection change of the film is detected in an optical fiber interference mode, so that the measurement of the sound pressure to be measured can be realized.
The embodiment provides a group of sensitive sizes of the sound pressure amplifying structure with adjustable frequency response:
the shell 1 and the four connecting rods 2 are made of the same material and are made of photosensitive resin; the external side length of the shell 1 is 25mm, the thickness of the shell is 6mm, the width and the thickness of the two internal cross frames are respectively 1mm, and the side length or the diameter of the internal hollow part is respectively the same as the side length or the diameter of the four primary sensitive films 2, the four secondary sensitive films 4 and the terminal sensitive film 5. The side length of the first-stage sensitive film 2 is 10mm, the side length of the second-stage sensitive film 4 is 2mm, and the diameter of the terminal sensitive film is 125 mu m. The connecting rod 2 is of an inclined structure with a wide top and a narrow bottom, the side length of the top surface is 5mm, the side length of the bottom surface is 1mm, and the height is 5 mm.
The four first-level sensitive films 2 are made of the same material and are all copper films with the thicknesses of 10 micrometers, 15 micrometers, 20 micrometers and 25 micrometers respectively.
The four secondary sensitive films 4 are made of the same material, and adopt TPU thin films, and the thicknesses of the TPU thin films are 15 mu m.
The terminal sensitive film 5 adopts 10 layers of graphene films, and the thickness of the graphene films is about 3.35 nm.
The second sealed cavity formed by the four secondary sensitive films 4, the terminal sensitive film 5 and the shell 1 is a rectangular cavity, the side length is 5mm, and the height is 0.1 mm.
The dimensions of the present invention may be greater or less than those given in the examples, and are within the scope of the dimensions that one skilled in the art can ascertain for use and the protection of this invention.
The working principle is as follows:
the interior of the sound pressure amplification structure with adjustable initial frequency response is in a sealed state; when external sound pressure acts on the four primary sensitive membranes 2, the primary sensitive membranes 2 are deformed, and the sound pressure acting on the surfaces of the primary sensitive membranes 2 is amplified through the four connecting rods 3 and is transmitted to the four secondary sensitive membranes 4; because the four secondary sensitive films 4 and the terminal sensitive film 5 form a sealed cavity, the secondary sensitive films are deformed under the action of the connecting rod, so that the pressure of the sealed cavity is changed and acts on the terminal sensitive film, and the sound pressure sensed by the terminal sensitive film 5 is amplified; in addition, the four primary sensitive membranes 2 and the four secondary sensitive membranes 4 have different membrane thicknesses or different thin-film materials, so that the whole structure has four different first-order natural frequencies, a proper membrane thickness is selected and proper materials are selected, the four first-order natural frequencies cover a wide frequency range, and the four first-order natural frequencies are spaced at equal intervals, the frequency response of the whole structure is the frequency response envelope of n single structures, and the sound pressure resonance amplification effect is high in the range from the 1 st first-order natural frequency to the nth first-order natural frequency. In the range lower than the 1 st first-order natural frequency, the sound pressure gain based on the auditory bone sound transmission principle of the human ear can also realize sound pressure amplification in a lower frequency range. According to the invention, the sound pressure amplification is carried out by adopting the multistage membrane structure, the frequency response is adjusted by adopting the four multistage membrane structures, the frequency response simulation is carried out on the embodiment in the figure 1, the frequency response simulation result shown in figure 5 is obtained, the sound pressure sensitivity is obviously improved by amplifying the sound pressure by the multistage membrane structures, and after the four multistage membrane structures are used, the sound pressure sensitivity is higher in a wider frequency range than that of a single membrane structure, the number of the multistage membrane structures is changed, the thickness of each stage of sensitive membrane is changed, the sensitivity can be enhanced in the wider frequency range or a specific frequency range, and thus the effect of adjusting the frequency is achieved. The amplified sound pressure signal can obtain the change of the central deflection of the terminal sensitive film in an optical fiber detection or electrical detection mode, so that the measurement of the sound pressure to be measured is realized.
The advantages of this embodiment:
(1) the structure of the embodiment has wide application range, can be matched and connected with the diaphragm type sound pressure sensor, only needs single-channel detection, and is simple in subsequent signal processing.
(2) The sound pressure resonance amplification device realizes transmission and amplification of sound pressure based on the auditory bone sound transmission principle of human ears, has a flat sound pressure amplification effect on sound signals with lower frequency, and has a high sound pressure resonance amplification effect on a range covered by a plurality of adjustable first-order natural frequencies.
(3) The adjustment of the frequency response of the embodiment is related to the film thickness and material parameters of the first-level sensitive film and the second-level sensitive film, the self-defined design of a plurality of first-order natural frequencies can be realized by changing the film thickness and selecting different film materials, and the sizes and the intervals of the plurality of natural frequencies are changed, so that the adjustment of the frequency response is realized.
(4) The amplification factor of the sensitivity of the sound sensor in the embodiment is related to the structure size, and different sound pressure amplification factors can be realized by changing the structure size of each component.
(5) The material used in the embodiment has wide selectable range, low process requirement and relatively simple manufacturing method. The shell and the connecting rod can be made of common resin, plastic, metal and the like, and are not limited to a single material; the shell can be spliced in multiple parts; the first-stage sensitive membrane and the second-stage sensitive membrane can use common elastic membranes and the like.
(6) The embodiment comprises two sealed cavities, conditions are provided for generating pressure difference, but the requirement on the air tightness of the sealed cavities is not high, the common manufacturing process can be realized, and the pressure intensity in the cavities has no special requirement.
(7) The deflection change of the terminal sensitive film in the embodiment can be detected by an optical fiber or electrical measurement mode on the signal amplified by sound pressure, and the method has the advantage of wide application range.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. The utility model provides a frequency response adjustable miniature acoustic pressure enlarged structure which characterized in that: the sensor comprises a shell (1), a plurality of primary sensitive membranes (2), a plurality of connecting rods (3), a plurality of secondary sensitive membranes (4) and a terminal sensitive membrane (5), wherein the shell (1) is of a rigid structure and comprises two cavity structures; the primary sensitive films (2) are used as receiving ends of sound pressure signals and fixed on the upper surface frame of the shell (1) to form a first boundary condition of peripheral fixed support; the connecting rods (3) are respectively connected with the centers of the primary sensitive membranes (2) and the secondary sensitive membranes (4) to enable the primary sensitive membranes and the secondary sensitive membranes to move together under the action of sound pressure; a plurality of primary sensitive membranes (2), a plurality of secondary sensitive membranes (4) and the shell (1) form a first sealed cavity together; the secondary sensitive films (4) are fixed on a frame in the shell (1) to form a second boundary condition of peripheral solid support, and form a second sealed cavity together with the terminal sensitive film (5) and the shell (1); the terminal sensitive film (5) is used as an amplification end of a sound pressure signal and fixed on the lower surface of the shell (1) to form a third boundary condition of peripheral fixing.
2. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the volume of the first sealed cavity is larger than that of the second sealed cavity, and air or inert gas is sealed in the first sealed cavity and the second sealed cavity.
3. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the shell (1) and the connecting rods (3) are made of rigid materials, and deformation under the action of sound pressure is negligible; the connecting rods (3) are made of low-density materials, so that the pre-deformation of the thin film caused by the mass of the connecting rods is negligible.
4. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the plurality of first-stage sensitive membranes (2), the plurality of second-stage sensitive membranes (4) and the terminal sensitive membrane (5) are of peripheral clamped thin film structures and are regular in shape; the plurality of the first-stage sensitive membranes (2) or the plurality of the second-stage sensitive membranes (4) have a plurality of different membrane thicknesses or adopt different thin-film materials.
5. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the number of the primary sensitive membranes (2) is equal to that of the secondary sensitive membranes (4), the primary sensitive membranes (2) and the secondary sensitive membranes (4) are in one-to-one correspondence, the primary sensitive membranes (2) are correspondingly connected through the connecting rods (3), the side lengths of the primary sensitive membranes (2) and the secondary sensitive membranes (4) are the same, the primary sensitive membranes (2) are the same in shape and size and are distributed in central symmetry, the connecting rods (3) are the same in shape and size and are distributed in central symmetry, and the secondary sensitive membranes (4) are the same in shape and size and are distributed in central symmetry.
6. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the connecting rods (3) are connected with the center positions of the primary sensitive membranes (2) and the secondary sensitive membranes (4) and are in a structure with a wide upper part and a narrow lower part, so that the contact area between the connecting rods (3) and the primary sensitive membranes (2) is larger than that between the connecting rods (3) and the secondary sensitive membranes (4).
7. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the areas of the plurality of first-stage sensitive membranes (2), the plurality of second-stage sensitive membranes (4) and the terminal sensitive membrane (5) are sequentially reduced, and an elastic membrane sensitive to sound pressure is used.
8. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the shell (1) is fixed with the plurality of primary sensitive membranes (2), the plurality of secondary sensitive membranes (4) and the terminal sensitive membrane (5) through physical adsorption, chemical adsorption or bonding; the connecting rods (3) are respectively fixed with the primary sensitive membranes (2) and the secondary sensitive membranes (4) through bonding.
9. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the optical fiber sensing module also comprises an optical fiber ceramic ferrule (6), and the terminal sensitive film (5) is adsorbed on the surface of the optical fiber ceramic ferrule (6); and then the optical fiber ceramic ferrule (6) is adhered to the bottom of the shell (1) by epoxy resin adhesive, no gap exists at the adhered part, and the optical fiber ceramic ferrule (6) is arranged as a part of the shell (1).
10. The miniature sound pressure amplifying structure with adjustable frequency response of claim 1, wherein: the frequency response adjustable miniature sound pressure amplification structure is realized through 3D printing integrated into one piece, separation component adhesion and MEMS technology.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111045715.5A CN113810823A (en) | 2021-09-07 | 2021-09-07 | Frequency response adjustable miniature sound pressure amplification structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111045715.5A CN113810823A (en) | 2021-09-07 | 2021-09-07 | Frequency response adjustable miniature sound pressure amplification structure |
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| CN113810823A true CN113810823A (en) | 2021-12-17 |
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|---|---|---|---|
| CN202111045715.5A Pending CN113810823A (en) | 2021-09-07 | 2021-09-07 | Frequency response adjustable miniature sound pressure amplification structure |
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| Country | Link |
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| CN (1) | CN113810823A (en) |
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2021
- 2021-09-07 CN CN202111045715.5A patent/CN113810823A/en active Pending
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