A bionic TENG sensor unit for artificial larynx and a preparation method thereof

Abstract

The application discloses a kind of bionic TENG sensor unit for artificial throat and preparation method thereof, it is related to artificial throat field, the sensor unit includes gradient microdome friction layer, strain amplification layer, electrode layer and back cavity substrate layer.Gradient microdome array realizes progressive contact by the gradient change of height diameter;Strain amplification layer utilizes cantilever beam-sliding block structure to convert vertical vibration into horizontal strain;Back cavity array is selectively amplified to specific frequency vibration based on Helmholtz resonance principle.The application also provides a corresponding preparation method, including back cavity forming, electrode deposition, microstructure manufacturing and surface treatment and the like steps.The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of artificial larynx, and particularly relates to a bionic TENG sensor unit for artificial larynx and a preparation method. BACKGROUND

[0002] An artificial larynx, also known as a speech aid, is a medical device that helps patients who have lost their ability to speak due to laryngectomy (after total laryngectomy) regain their speech function.

[0003] Traditional artificial larynx can be mainly divided into two categories:

[0004] Mechanical (pneumatic) artificial larynx: shaped like a short tube, one end connected to a tracheostomy, the other end connected to the esophageal inlet. When the lung airflow is exhaled through the stoma, it drives the membrane in the artificial larynx to vibrate, producing a basic sound source, which is then guided to the oral cavity. Patients can form words by normal lip, tongue, and tooth coordination. Its voice is monotonous, similar to a "robot", but it can effectively communicate.

[0005] Electronic artificial larynx: more commonly used, shaped like a small flashlight. Its head has a vibrating membrane, which is tightly attached to the soft part of the neck (such as the submental region) when in use. Press the switch, the internal electromagnetic oscillator makes the vibrating membrane produce sound waves, which are transmitted through the neck tissue into the pharyngeal cavity and oral cavity, and the patient also forms language by changing the mouth shape. Its voice is also relatively mechanical, but it is easy to learn and use.

[0006] With the development of sensors, sensor-type artificial larynx has also appeared. Existing sensor-type artificial larynx devices are mainly based on electromagnetic sensors or piezoelectric sensors, which have problems such as insufficient sensitivity, discomfort to wear, sensitivity to external noise, etc. In particular, for the weak gas sound produced by patients with vocal cord paralysis, traditional sensors are difficult to effectively detect.

[0007] Although TENG technology has the characteristics of high sensitivity, existing TENG sensors still have the following problems when detecting laryngeal vibration: limited effective contact area leading to insufficient charge transfer; lack of selectivity for specific frequency vibration; microstructure is easy to wear and affect service life; difficult to distinguish between speech vibration and non-speech motion interference. SUMMARY

[0008] To solve the problems of the prior art, the application provides a bionic TENG sensor unit for an artificial larynx and a preparation method, aiming at solving the problems of insufficient sensitivity of a traditional sensor, difficulty in effectively detecting weak air sound and single collection frequency of the prior art. The bionic TENG sensor unit comprises, from top to bottom, a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer. The gradient micro-dome array realizes progressive contact through gradient changes in height and diameter, and significantly increases the effective contact area. The strain amplification layer converts vertical vibration into horizontal strain by using a cantilever beam-sliding block structure, and realizes mechanical amplification. The back cavity array selectively amplifies vibrations of different frequencies based on the Helmholtz resonance principle. The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

[0009] To achieve the above-mentioned purpose, in a first aspect of the application, a bionic TENG sensor unit for an artificial larynx is provided, comprising, from top to bottom, a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer.

[0010] The flexible friction layer has a gradient micro-dome array, the height and diameter of the micro-dome gradually decrease from the center of the array to the edge;

[0011] The strain amplification layer comprises a cantilever beam-sliding block microstructure;

[0012] The electrode layer;

[0013] The substrate layer has a bionic cochlea type back cavity array;

[0014] The flexible friction layer and the electrode layer constitute a contact-separation type friction nanogenerator.

[0015] In a specific embodiment, the flexible friction layer is made of a composite material of PDMS and BST nanoparticles, the mass fraction of the BST nanoparticles is 5%-20%, and the surface of the flexible friction layer is subjected to ultraviolet ozone treatment to form a hard crosslinked layer with a thickness of 50-200nm.

[0016] In a specific embodiment, the PDMS / BST composite material uniformly disperses a nanofiber reinforcing body, the nanofiber reinforcing body is cellulose nanofiber or carbon nanotube, the mass fraction of the nanofiber reinforcing body is 0.5%-3%, the length of the nanofiber reinforcing body is 1-20μm, and the diameter of the nanofiber reinforcing body is 10-100nm.

[0017] In a specific embodiment, the cantilever beam-sliding block microstructure in the strain amplification layer comprises:

[0018] A fixed end;

[0019] A cantilever beam extending from the fixed end, the thickness of the cantilever beam is 10-50μm;

[0020] a slider set at the free end of the cantilever beam;

[0021] wherein the slider has a displacement space of 1-5 μm in the vertical direction, and can convert the vertical vibration into a horizontal tensile strain at the root of the cantilever beam, with a strain amplification factor of 5-10 times.

[0022] In a specific embodiment, the bionic cochlea type back cavity array comprises 3-6 micro back cavities connected in series, each micro back cavity has a depth of 50-200 μm and a diameter of 1-3 mm, and the resonance frequency difference between adjacent back cavities is 50-100 Hz, which collectively covers the laryngeal vibration frequency range of 100-500 Hz.

[0023] In a specific embodiment, an anisotropic conductive layer is provided between the electrode layer and the strain amplification layer, which has an electrical conductivity of 1-10 S / m in the vertical direction and an electrical conductivity of less than 10 -6 S / m in the horizontal direction, and a thickness of 10-50 μm.

[0024] In this technical solution, the added anisotropic conductive layer ensures efficient conduction of electrical signals in the vertical direction, while cutting off the horizontal current path between adjacent sensing units. This design effectively avoids the common signal "cross talk" problem in arrayed sensors, ensuring the purity of the output signal of each independent sensing unit (or "functional pixel point"), thereby improving the ability of the entire sensor to accurately spatially resolve complex vibration patterns.

[0025] In a specific embodiment, the entire sensor unit is encapsulated in a flexible encapsulant, and the flexible encapsulant comprises:

[0026] a breathable layer in contact with the skin, having a thickness of 100-300 μm and a microporous structure with a pore size of 5-20 μm;

[0027] a soundproof sealing layer facing away from the skin, having a thickness of 200-500 μm and an acoustic impedance greater than 2.5 MRayl.

[0028] In a specific embodiment, in the gradient micro-dome array, the central micro-dome has a height of 20-50 μm and a diameter of 50-100 μm, the edge micro-dome has a height of 5-15 μm and a diameter of 20-50 μm, and the distance between adjacent micro-domes is 10-30 μm.

[0029] In a second aspect of the present application, a method for preparing the bionic TENG sensor unit provided in the first aspect is provided, comprising the following steps:

[0030] providing a flexible substrate as a base layer;

[0031] Forming a pattern of a sacrificial layer on the base layer by a photolithography process, and forming a back cavity structure after etching;

[0032] Magnetron sputtering deposition of a copper electrode layer on the back cavity structure, with a thickness of 100-500 nm;

[0033] Forming a cantilever-slip microstructure on the electrode layer by a micro-mold method;

[0034] Forming a PDMS / BST composite layer on the microstructure by a two-step spin coating process: 500-1000 rpm for 10-20 s in the first step, and 1000-3000 rpm for 30-60 s in the second step;

[0035] Forming a gradient micro-dome array on the surface of the PDMS / BST layer by laser etching;

[0036] Ultraviolet ozone treatment for 10-30 minutes under the conditions of a power of 100-300 W and an oxygen flow rate of 0.5-2 L / min;

[0037] Thermal curing at 60-80℃ for 2-4 hours to complete the preparation of the sensor unit.

[0038] In a specific embodiment, when forming the PDMS / BST composite layer, the PDMS prepolymer is first subjected to vacuum degassing treatment, with a degassing time of 30-60 minutes and a pressure of less than 0.1 Pa; then the BST nanoparticles and nanofiber reinforcing agent are sequentially added to the PDMS prepolymer, and a three-dimensional mixer is used to mix at a speed of 1000-2000 rpm for 30-60 minutes.

[0039] Compared with the prior art, the laryngeal vibration sensor with a gradient modulus micro-dome and a back cavity acoustic amplification structure provided by the application has the following remarkable beneficial effects through its innovative bionic structure and composite process:

[0040] 1. The application constitutes an organic whole through ingenious structural design. The gradient micro-dome array is responsible for maximizing the contact power generation efficiency, the strain amplification layer is responsible for converting weak vibrations in any direction into efficient interfacial tensile strain, and the back cavity array is responsible for pre-selecting and amplifying vibrations of a specific frequency. The three constitute a "frequency selection-mechanical amplification-high efficiency power generation" cooperative work chain. Specifically, the back cavity array preferentially amplifies signals in the target frequency band, followed by the strain amplification layer which performs secondary amplification of mechanical vibrations in the frequency band and optimizes its action form (into tensile strain), and finally the gradient micro-dome generates electric charges with maximum efficiency under the driving of the optimized form. This cascading amplification and functional synergy enables the sensor to achieve a system-level performance leap in core indicators such as sensitivity, frequency selectivity, and signal-to-noise ratio, which cannot be achieved by any single technical feature.

[0041] 2. Significantly improved detection sensitivity and signal-to-noise ratio of weak vibration signals: The gradient modulus micro-dome array generates a progressive stress distribution when contact is separated, effectively increasing the contact area and effectively increasing the amount of charge transfer, thereby enhancing the electrical signal output from the source; the integrated Helmholtz back cavity structure mechanically resonates the specific low frequency sound pressure of the laryngeal vibration in the range of 100-500Hz, providing a sound pressure gain of about 20dB, and realizing physical preamplification of weak signals such as air sound; the cantilever beam-sliding block strain amplification layer simulates the spider slit organ, which converts the vertical micro-vibration displacement into a larger horizontal tensile strain on the interface of the friction layer, achieving a mechanical strain amplification of 5-10 times, and greatly improving the response capability of the sensor to nanoscale weak vibrations.

[0042] 3. Realize the frequency selective perception and spatial decoupling of complex laryngeal vibration signals: The bionic cochlea type back cavity array is composed of a plurality of micro back cavities with different resonance frequencies in series, which can selectively amplify different frequency components (corresponding to different speech elements) in laryngeal vibration; combined with the design of patterned independent electrodes, it can map vibration signals of different frequencies to different spatial positions for collection, thereby realizing the preliminary separation of signals at the hardware level, providing high signal-to-noise ratio and clear feature input signals for the back-end speech recognition algorithm, and significantly improving the accuracy of speech recognition.

[0043] 4. Greatly enhance the durability and long-term working stability of the sensor. Through the strengthening process of ultraviolet ozone treatment combined with nanofiber enhancement, a wear-resistant and anti-aging hard skin is formed on the surface of the PDMS / BST micro-dome, and the mechanical strength of the material is also enhanced from the bulk phase. This treatment enables the micro-dome structure to maintain its complete morphology and power generation performance after more than 100,000 cycles of contact-separation tests, effectively overcoming the technical bottleneck of easy wear and aging of traditional flexible microstructures, and ensuring the reliability of the sensor under long-term and frequent use. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is a structural schematic diagram of a typical TENG sensor unit;

[0045] Figure 2 is a structural schematic diagram of a TENG sensor unit provided by an embodiment of the present application;

[0046] Figure 3 is a structural schematic diagram of a bionic cochlea type back cavity array. DETAILED DESCRIPTION

[0047] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, for the purpose of explanation, and are not to be understood as limiting the present application.

[0048] Embodiment 1

[0049] As shown in the drawings, Figure 1 Figure 1 A typical TENG sensor unit (Triboelectric Nanogenerator) generates equal and opposite static charges on the surfaces when two different materials are in contact and separated. In Embodiment 1, there is a fixed electrode, a fixed friction layer, and a movable independent friction layer (skin). The principle is as follows:

[0050] Initial contact: when the throat skin contacts the PDMS micro dome array on the surface of the sensor in vibration, the charge is transferred because the skin and the PDMS are far apart in the triboelectric series (the skin is usually positively charged and the PDMS is negatively charged). The PDMS surface acquires a negative charge and the skin surface acquires an equal positive charge.

[0051] Separation process: when the vibration separates the skin from the sensor, the positive charge on the skin is "taken away". Due to electrostatic induction, a positive charge will be induced on the copper electrode to shield the negative charge on the PDMS. At this time, if the electrode is connected to the reference ground (earth or other parts of the human body) through an external circuit, free electrons will flow from the ground to the electrode, forming a transient current.

[0052] Recontact: when the skin contacts the sensor again, the electrostatic balance is broken and the induced positive charge is no longer needed. Electrons will flow back to the ground from the electrode through the external circuit, forming a reverse transient current.

[0053] As shown in the drawings, Figures 2-3 The first embodiment of the present application provides a bionic TENG sensor unit for an artificial larynx, which comprises, from top to bottom, a flexible friction layer 100 with a gradient micro dome array 101, a fixed electrode 200, a fixed friction layer 300, and a movable independent friction layer (skin) 400.

[0054] The flexible friction layer 100 has a gradient micro dome array 101, the height and diameter of the micro dome gradually decreasing from the center of the array to the edge;

[0055] When pressed, the highest and most prominent micro dome in the center area is the first to contact. As the pressure increases, the contact area gradually expands from the center to the edge like water waves. This avoids all micro domes "hard" contact at the same time, making the contact stress distribution more uniform, avoiding local stress concentration, and protecting the microstructure;

[0056] ​Meanwhile, since micro-domes of different sizes have different stiffness (larger domes are softer, smaller domes are harder), they are activated at different pressure stages. This design ensures a high and continuously increasing effective contact area throughout the whole range from low to high pressure, rather than quickly reaching saturation;

[0057] Furthermore, the amount of charge generated by triboelectricity is directly related to the actual contact area. The larger and more linear increase of effective contact area brought by the gradient structure directly translates to a more significant and linear increase of charge transfer, thus improving the output voltage / current signal of TENG;

[0058] For loud / strong vibrations: all sizes of micro-domes are working, producing strong signals. For weak acoustic / weak vibrations: only some of the highest micro-domes in the central region can experience contact separation, but still can produce detectable signals. This makes the sensor more sensitive to weak signals and has a wider dynamic range;

[0059] Strain amplification layer 200, containing cantilever beam 201 - slider 202 microstructure;

[0060] Electrode layer 300;

[0061] Substrate layer 400 with biomimetic cochlea-style back cavity array 401;

[0062] Wherein, the flexible triboelectric layer 100 and the electrode layer 300 constitute a contact-separation type triboelectric nanogenerator.

[0063] In practical applications, the weak vertical vibration of the throat is transmitted to the entire sensor, and the flexible triboelectric layer 100 moves downward and presses the slider 202. After the slider 202 is forced, it converts the vertical force into a bending moment on the cantilever beam 201, causing the cantilever beam 201 to bend downward. When the cantilever beam 201 bends, the greatest tensile strain occurs at its root. Due to the close contact and friction between the triboelectric layer and the top of the slider 202, this horizontal tensile strain at the root of the cantilever beam 201 is directly transmitted to the local area of the flexible triboelectric layer 100 directly above it. Result: small vertical displacement → large horizontal tensile strain at the root of the cantilever beam 201 → local area of the triboelectric layer is significantly stretched;

[0064] Conversion of displacement to strain (amplification mechanism)

[0065] For a cantilever beam 201 with a concentrated load at the end, the maximum strain occurs at the root of the beam. The formula for calculating strain (ε) is: ε = (3 E h δ) / (2 L²)

[0066] ε: maximum tensile / compressive strain at the root of the beam, E: Young's modulus of the beam material, h: thickness of the beam, δ: vertical displacement of the free end of the beam, L: length of the beam;

[0067] Amplification factor: strain ε is proportional to displacement δ. By reducing the beam length L and increasing the beam thickness h, strain amplification of the tiny displacement δ can be achieved.

[0068] Example quantification: assume cantilever beam 201 parameters: L = 100 μm, h = 20 μm, δ = 1 μm (from a weak vibration from the throat).

[0069] Substitute into the formula, the strain ε at the root = (3 E 20 1) / (2 100²). (E will be dropped out, we look at the relative value).

[0070] Calculation result: the strain generated at the root is about 0.003 (or 3000 micro-strain).

[0071] For comparison, directly stretching the friction layer, 1 μm displacement may only generate 0.0001 order of strain.

[0072] This means that the cantilever beam 201 structure amplifies the 1 μm vertical displacement to the root 3000 micro-strain horizontal deformation, and the mechanical amplification factor can reach dozens of times.

[0073] It is worth mentioning that, in physics, the electrode layer 300 is located below the strain amplification layer 200, and a thin insulating layer (such as PI) or other types of anisotropic conductive layer can be provided between them to ensure electrical isolation or vertical conduction.

[0074] At the same time, the strain amplification layer 200 itself is insulating (which can be made of PDMS and other polymers), and it does not directly participate in conduction. Its role is to "disturb" the "contact state" between the friction layer above it and the electrode layer 300 below it, thereby indirectly modulating the electrical signal generated on the electrode layer 300.

[0075] In the embodiment, the flexible friction layer 100 is made of a composite material of PDMS and BST nanoparticles, wherein the mass fraction of the BST nanoparticles is 5%-20%, and the surface of the flexible friction layer 100 is subjected to ultraviolet ozone treatment to form a hard cross-linked layer with a thickness of 50-200 nm.

[0076] In the embodiment, the PDMS / BST composite material uniformly disperses a nanofiber reinforcing body, the nanofiber reinforcing body is cellulose nanofiber or carbon nanotube, and the mass fraction of the nanofiber reinforcing body is 0.5%-3%, the length of the nanofiber reinforcing body is 1-20 μm, and the diameter of the nanofiber reinforcing body is 10-100 nm.

[0077] In the embodiment, the cantilever beam 201-slid 202 microstructure in the strain amplification layer 200 includes:

[0078] a fixed end;

[0079] a cantilever beam 201 extending from the fixed end, with a thickness of 10-50 μm;

[0080] a slid 202 arranged at the free end of the cantilever beam 201;

[0081] wherein the slid 202 has a displacement space of 1-5 μm in the vertical direction, and is capable of converting the vertical vibration into a horizontal tensile strain on the root of the cantilever beam 201, with a strain amplification factor of 5-10 times.

[0082] In the embodiment, the bionic cochlea type back cavity array 401 includes 3-6 micro back cavities in series, each micro back cavity has a depth of 50-200 μm and a diameter of 1-3 mm, and the resonance frequency difference between adjacent back cavities is 50-100 Hz, which collectively covers the laryngeal vibration frequency range of 100-500 Hz.

[0083] In the embodiment, an anisotropic conductive layer is arranged between the electrode layer 300 and the strain amplification layer 200, which has an electrical conductivity of 1-10 S / m in the vertical direction and an electrical conductivity of less than 10 -6 S / m in the horizontal direction, with a thickness of 10-50 μm.

[0084] In the embodiment, the sensor unit as a whole is packaged in a flexible package, which includes:

[0085] a breathable layer in contact with the skin, with a thickness of 100-300 μm and a microporous structure with a pore size of 5-20 μm;

[0086] a soundproof sealing layer facing away from the skin, with a thickness of 200-500 μm and an acoustic impedance greater than 2.5 MRayl.

[0087] In the embodiment, in the gradient micro-dome array 101, the central micro-dome has a height of 20-50 μm and a diameter of 50-100 μm; the edge micro-dome has a height of 5-15 μm and a diameter of 20-50 μm; and the distance between adjacent micro-domes is 10-30 μm.

[0088] In the first embodiment of the present application, a method for preparing a bionic TENG sensor unit is also provided, which includes the following steps:

[0089] providing a flexible substrate as a base layer 400;

[0090] A sacrificial layer pattern is formed on the base layer 400 by a photolithography process, and a back cavity structure is formed after etching;

[0091] A copper electrode layer 300 is deposited on the back cavity structure by magnetron sputtering, with a thickness of 100-500 nm;

[0092] A microstructure of cantilever beam 201 and slider 202 is formed on the electrode layer 300 by a micro-mold method;

[0093] A PDMS / BST composite layer is formed on the microstructure by a two-step spin coating process: the first step is spin coating at 500-1000 rpm for 10-20 s, and the second step is spin coating at 1000-3000 rpm for 30-60 s;

[0094] A gradient micro-dome array 101 is formed on the surface of the PDMS / BST layer by laser etching;

[0095] Ultraviolet ozone treatment is performed at a power of 100-300 W and an oxygen flow rate of 0.5-2 L / min for 10-30 minutes;

[0096] Thermal curing is performed at 60-80°C for 2-4 hours to complete the preparation of the sensor unit.

[0097] In this embodiment, when forming the PDMS / BST composite layer, the PDMS prepolymer is first subjected to vacuum degassing treatment, with a degassing time of 30-60 minutes and a pressure less than 0.1 Pa; then BST nanoparticles and nanofiber reinforcing agents are added to the PDMS prepolymer in sequence, and a three-dimensional mixer is used to mix at a speed of 1000-2000 rpm for 30-60 minutes.

[0098] Example 2

[0099] As shown in Figure 2 , the sensor unit includes a flexible friction layer 100, a strain amplification layer 200, an electrode layer 300, and a base layer 400. The flexible friction layer 100 is a composite material of PDMS and 20% mass fraction of BST nanoparticles, and in the surface gradient micro-dome array 101, the central micro-dome has a height of 35 μm and a diameter of 80 μm, and the edge micro-dome has a height of 10 μm and a diameter of 30 μm.

[0100] The cantilever beam 201 in the strain amplification layer 200 has a thickness of 25 μm, and the slider 202 has a displacement space of 3 μm, which can amplify a vertical displacement of 0.5 μm to a horizontal strain of 5 μm. The electrode layer 300 uses a copper electrode with a thickness of 200 nm, and an anisotropic conductive layer is provided below the electrode, with a vertical conductivity of 5 S / m and a horizontal conductivity of 10⁻ 8 S / m.

[0101] The back cavity array 401 in the substrate layer 400 includes 6 micro back cavities (3 types), with depths of 50 μm, 100 μm and 200 μm, and corresponding resonance frequencies of 500 Hz, 350 Hz and 150 Hz, respectively.

[0102] In the preparation, photoresist is first spin-coated on a silicon substrate, a back cavity pattern is formed by photoetching, and the etching depth is 50-200 μm. Then, a 200 nm copper electrode is deposited by magnetron sputtering under the condition of a power of 500 W and an argon pressure of 1 Pa. Then, the cantilever beam 201-sliding block 202 structure is formed by a micro-mold method, and the mold precision is ±1 μm.

[0103] The preparation of the PDMS / BST composite material includes: mixing the PDMS prepolymer with the curing agent at a ratio of 10:1, adding BST nanoparticles and 1% mass fraction of carbon nanotubes, mixing by a three-dimensional mixer at 1500 rpm for 45 minutes, and vacuum degassing for 40 minutes. A two-step spin coating process is adopted: 800 rpm for 15 s in the first step and 2000 rpm for 45 s in the second step.

[0104] Laser etching is performed by using an ultraviolet laser with a wavelength of 355 nm and a power of 15 W, and a scanning speed of 100 mm / s, to form a gradient micro-dome array 101 on the surface of the PDMS / BST layer. Finally, ultraviolet ozone treatment is performed under the condition of a power of 200 W and an oxygen flow rate of 1 L / min for 20 minutes, and thermal curing is performed at 70°C for 3 hours.

[0105] The above describes the preferred embodiments of the present application in detail. It should be understood that those skilled in the art can make many modifications and changes to the present application without creative labor, based on the concept of the present application. Therefore, any technical solution that can be obtained by logical analysis, reasoning or limited experiments by those skilled in the art based on the prior art and the concept of the present application should be within the protection scope defined by the claims.

Claims

1. A biomimetic TENG sensor unit for an artificial larynx, characterized in that, Including those stacked sequentially from top to bottom: A flexible friction layer with a gradient microdome array, wherein the height and diameter of the microdome decrease in a gradient from the center of the array to the edge; Strain amplification layer, containing cantilever beam-slider microstructure; Electrode layer; The basal layer has a biomimetic cochlear dorsal cavity array; The flexible friction layer and the electrode layer together form a contact-separation type triboelectric nanogenerator. The cantilever beam-slider microstructure in the strain amplification layer includes: Fixed end; The cantilever beam extending from the fixed end has a thickness of 10-50μm; A slider is installed at the free end of the cantilever beam; The slider has a displacement space of 1-5 μm in the vertical direction, which can convert vertical vibration into horizontal tensile strain at the root of the cantilever beam, with a strain amplification factor of 5-10 times.

2. The sensor unit as described in claim 1, characterized in that, The flexible friction layer is a PDMS / BST composite material made of PDMS and BST nanoparticles, wherein the mass fraction of BST nanoparticles is 5%-20%, and the surface of the flexible friction layer is treated with ultraviolet ozone to form a hard cross-linked layer with a thickness of 50-200 nm.

3. The sensor unit as described in claim 2, characterized in that, The PDMS / BST composite material contains uniformly dispersed nanofiber reinforcements, which are cellulose nanofibers or carbon nanotubes with a mass fraction of 0.5%-3%, a length of 1-20 μm, and a diameter of 10-100 nm.

4. The sensor unit as described in claim 1, characterized in that, The bionic cochlear dorsal cavity array comprises 3-6 micro dorsal cavities connected in series. Each micro dorsal cavity has a depth of 50-200μm and a diameter of 1-3mm. The resonant frequency difference between adjacent dorsal cavities is 50-100Hz, collectively covering the laryngeal vibration frequency range of 100-500Hz.

5. The sensor unit as described in claim 1, characterized in that, An anisotropic conductive layer is disposed between the electrode layer and the strain amplification layer. This layer has a conductivity of 1-10 S / m in the vertical direction and a conductivity of less than 10 S / m in the horizontal direction. -6 S / m, thickness is 10-50μm.

6. The sensor unit as described in claim 1, characterized in that, The sensor unit is entirely encapsulated within a flexible package, which includes: The breathable layer that comes into contact with the skin has a thickness of 100-300μm and a microporous structure with a pore size of 5-20μm. The soundproof sealing layer facing away from the skin has a thickness of 200-500μm and an acoustic impedance greater than 2.5MRayl.

7. The sensor unit as described in claim 1, characterized in that, In the gradient microdome array, the height of the central microdome is 20-50 μm and the diameter is 50-100 μm; the height of the edge microdome is 5-15 μm and the diameter is 20-50 μm; the spacing between adjacent microdomes is 10-30 μm.

8. A method for preparing a biomimetic TENG sensor unit as described in any one of claims 1-7, characterized in that, Includes the following steps: Provide a flexible substrate as the base layer; A sacrificial layer pattern is formed on the substrate using photolithography, and then etched to form a back cavity structure. A copper electrode layer with a thickness of 100-500 nm is deposited by magnetron sputtering on the cavity structure. A cantilever beam-slider microstructure is formed on the electrode layer using a micromold method; A two-step spin coating process is used to form a PDMS / BST composite layer on the microstructure: the first step is spin coating at 500-1000 rpm for 10-20 s, and the second step is spin coating at 1000-3000 rpm for 30-60 s. A gradient microdome array was formed on the surface of the PDMS / BST layer by laser etching; Perform ultraviolet ozone treatment for 10-30 minutes at a power of 100-300W and an oxygen flow rate of 0.5-2L / min. The sensor unit is fabricated by thermosetting at 60-80℃ for 2-4 hours.

9. The method as described in claim 8, characterized in that, When forming the PDMS / BST composite layer, the PDMS prepolymer is first subjected to vacuum degassing treatment for 30-60 minutes at a pressure of less than 0.1 Pa. Then, BST nanoparticles and nanofiber reinforcements are added to the PDMS prepolymer in sequence and mixed for 30-60 minutes at a speed of 1000-2000 rpm using a three-dimensional mixer.

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