Kazoo type acoustoelectric converter

Abstract

The kazoo type acoustoelectric converter comprises a shell, a vocal cavity is formed in the shell in a hollow mode, air holes communicated with the vocal cavity are formed in the two ends of the shell, a membrane hole is formed in the shell and used for arranging an acoustoelectric conversion module, and the acoustoelectric conversion module is used for sensing sound wave signals and converting the sound wave signals into electric signals; the acoustic-electric conversion module comprises a first plastic film electrode, a piezoelectric fiber film and a second plastic film electrode which are sequentially arranged in a contact mode, round holes are formed in the first plastic film electrode and the second plastic film electrode, and a first metal conductive layer is arranged on the face, making contact with the piezoelectric fiber film, of the first plastic film electrode. A second metal conductive layer is arranged on one surface, in contact with the piezoelectric fiber film, of the second plastic film electrode; and the first metal conductive layer and the second metal conductive layer are respectively connected with external wiring terminals. A kazoo type structure is adopted, sound waves can be collected in parallel to the surface of equipment, the limitation of traditional equipment is overcome, and the collection efficiency of the sound waves is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sound-to-electric conversion, and in particular to a kazoo-type sound-to-electric converter. Background Art

[0002] Acoustoelectric conversion technology, as a key technology for converting sound wave energy into electrical energy, is widely used in many fields such as sound wave detection, recording, voice recognition and energy harvesting. Traditionally, such devices mainly rely on piezoelectric materials, such as lead zirconate titanate (PZT) and polyvinylidene fluoride (PVDF), which have the ability to directly convert sound wave signals into electrical signals.

[0003] In previous studies, researchers have tried a variety of methods to improve the efficiency of acoustic-to-electric conversion. For example, by integrating a Helmholtz resonator to enhance the vibration of the sound wave, the conversion efficiency can be improved. Applied Energy In 2023, Li et al. published an article titled "A renewable low-frequency acoustic energy harvesting noise barrier for high-speed railways using a Helmholtz resonator and a PVDF film" (an acoustic-to-electric conversion device combining a Helmholtz resonator and a PVDF film). The acoustic-to-electric conversion device successfully increased the acoustic-to-electric output from 52.20mV to 35.8V, which is enough to convert the low-frequency sound generated by high-speed trains. In November 2023, Li et al. published an article titled "A renewable low-frequency acoustic energy harvesting noise barrier for high-speed railways using a Helmholtz resonator and a PVDF film" (an acoustic-to-electric conversion device combining a Helmholtz resonator and a PVDF film). The acoustic-to-electric conversion device successfully increased the acoustic-to-electric output from 52.20mV to 35.8V, which is enough to convert the low-frequency sound generated by high-speed trains. Applied Acoustics An article titled "Harvesting low-frequency acoustic energy using quarter-wavelength straight-tube acoustic resonator" (an acoustic-electric device combining a quarter-wavelength straight-tube resonator and a PVDF fiber membrane) was published in the journal. The device generated a voltage of 1.48V under the action of a 146Hz, 100dB sound wave. Although these studies have achieved certain results, these devices still require sound waves to be introduced perpendicular to the surface of the device and mainly respond to sound waves perpendicular to its two-dimensional surface, while the conversion efficiency for sound waves parallel to the device is extremely low. At the same time, the high density and rigidity of traditional piezoelectric materials also make it difficult to obtain large electrical energy from sound waves, and the electrical output power of these devices is also relatively low.

[0004] In addition, due to the design limitations of existing acoustic-to-electric conversion devices, the propagation path of sound waves is restricted, which in turn affects the collection efficiency of sound waves. This vertical introduction method limits the integration flexibility of the device, especially when the acoustic-to-electric conversion device needs to be integrated into a planar electronic device. This limitation is particularly obvious. In acoustic devices, the incident angle of sound waves has an important influence on their reflection and reception efficiency. According to the acoustic wave reflection mechanism, sound waves are similar to light and can undergo specular reflection. Their reflection angle and direction are determined by the incident angle and the geometric shape of the boundary. For sound waves parallel to the surface of the device, due to the small incident angle, their reflection on the surface of the device may be scattered in different directions, making it difficult for the sound waves to be effectively collected. In addition, the way sound waves are received is limited by the device design. For example, microphones are usually more sensitive to sounds in a specific direction, but are not sensitive enough to parallel incident sound waves; however, parallel incident sound waves can cover the receiving area of ​​the device more evenly, which is an advantage for acoustic devices in planar electronic devices. Planar electronic devices usually require devices to respond uniformly on a plane, and parallel incident sound waves can better meet this requirement due to their consistent incident angles. At the same time, parallel incident sound waves have less reflection and diffraction on the device, which helps reduce internal interference and improve signal clarity and device performance. Therefore, how to achieve parallel collection and efficient conversion of sound waves is still a difficult problem that needs to be overcome in the field of sound-to-electricity conversion technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, efficiently convert sound waves parallel to the planar device into electrical energy, and provide a kazoo-type sound-to-electric converter.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A kazoo-type sound-to-electric converter comprises a shell, wherein a sound cavity is hollowly arranged inside the shell, air holes communicating with the sound cavity are arranged at both ends of the shell, and a membrane hole is opened on the shell, wherein the membrane hole is used to set a sound-to-electric conversion module, wherein the sound-to-electric conversion module is used to sense sound wave signals and convert them into electrical signals; the sound-to-electric conversion module comprises a first plastic film electrode, a piezoelectric fiber film and a second plastic film electrode which are sequentially arranged in contact with each other, wherein the first plastic film electrode and the second plastic film electrode are both provided with circular holes, a first metal conductive layer is arranged on a side of the first plastic film electrode in contact with the piezoelectric fiber film, a second metal conductive layer is arranged on a side of the second plastic film electrode in contact with the piezoelectric fiber film, and the first metal conductive layer and the second metal conductive layer are used to be connected to external wiring terminals respectively.

[0007] The present invention generates resonance in the sound cavity of the kazoo shell by allowing parallel sound waves to enter the interior of the kazoo shell through the side entrance, thereby exciting the vibration of the piezoelectric fiber film, thereby generating electric energy. The generated electric energy is then transmitted to the external circuit through the first metal electrode layer and the second metal electrode layer on the first plastic film electrode and the second metal film electrode. The electric energy is captured by the first metal electrode layer and the second metal electrode layer, and the sound-to-electric conversion module is fixed by the membrane hole. By using circular through holes on the first plastic film electrode and the second plastic film electrode, the core vibration area can be increased, the vibration is more obvious, the sound amplification effect is better, and the vibration of the metal electrode can be more effectively driven to generate a larger voltage.

[0008] Preferably, the shell includes an upper cover plate and a lower cover plate, the upper cover plate and the lower cover plate are connected by a first pad and a second pad, a sound cavity is formed between the first pad and the second pad, the membrane hole is arranged on the upper cover plate or the lower cover plate, the first pad and the second pad are both inclined to form a trapezoidal sound cavity, the trapezoidal sound cavity includes a wide mouth end and a narrow mouth end, the wide mouth end is connected to the air inlet, and the narrow mouth end is connected to the air outlet.

[0009] Preferably, the preparation method of the first plastic film electrode or the second plastic film electrode comprises: using a plastic film as a substrate, coating a metal on the plastic film to form a first plastic film electrode with a first metal electrode layer or a second plastic film electrode with a second metal electrode layer, the method of coating the metal on the plastic film comprises one of spraying, electroplating, or physical vapor deposition, the thickness of the plastic film is 50-150μm, and the thickness of the first metal electrode layer or the second metal electrode layer is less than 50nm or greater than 1000nm.

[0010] Preferably, the preparation method of the piezoelectric fiber film includes: dissolving polyvinylidene fluoride particles in a dimethylformamide solvent at 65°C to prepare a polyvinylidene fluoride solution, adding acetone to the polyvinylidene fluoride solution, and preparing the piezoelectric fiber film by electrospinning, wherein the diameter of the nanofibers in the piezoelectric fiber film ranges from 10nm to 5µm, and the thickness of the piezoelectric fiber film ranges from 20µm to 100μm.

[0011] Preferably, the piezoelectric fiber film has a thickness of 60 μm.

[0012] Preferably, the length x width dimensions of the piezoelectric fiber film are 40 mm x 30 mm, the diameters of the circular holes on the first plastic film electrode and the second plastic film electrode are both 2 mm, and the inner diameter of the film hole is larger than the circular hole diameter.

[0013] Preferably, the piezoelectric fiber film is made of fiber material by electrospinning, and the fiber material includes at least one piezoelectric polymer, and the piezoelectric polymer is polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, silk fibroin, polyhydroxybutyric acid, polyacrylonitrile, nylon-7, nylon-11, polylactic acid, polyimide, polyimide copolymer, polystyrene, polycarbonate or poly-L-lactic acid.

[0014] Preferably, the fiber material comprises at least two piezoelectric polymers, and the piezoelectric fiber film is made by blending at least two piezoelectric polymers, and the blending method comprises blending two or more piezoelectric polymers in the same spinning solution, or dissolving different piezoelectric polymers in the spinning solution separately.

[0015] Preferably, the piezoelectric fiber film is made of a composite of fiber material and inorganic material, the inorganic material adopts inorganic piezoelectric material or non-piezoelectric material, the inorganic piezoelectric material includes one of zinc oxide, titanate, niobate or lead salt, the non-piezoelectric material includes lithium borosilicate polar glass ceramic and inorganic salt, the inorganic salt includes one of NaCl, KCl, Na2SO4, Na2CO3 or CaCl2.

[0016] Preferably, the piezoelectric fiber film is made of a composite of multiple layers of fiber materials, wherein the multiple layers of fiber materials include a non-woven fabric support layer made of polyethylene terephthalate, an electrospun middle layer made of polyacrylonitrile, and a fiber layer made of cellulose.

[0017] The present invention utilizes the effect of sound amplification through the structure of the kazoo-type shell. Within a certain thickness range, the nano-piezoelectric fiber film vibrates in the sound cavity. Under the reasonable size settings of the shell, the membrane hole and the acoustic-to-electric conversion module, it is ensured that the maximum voltage can be generated, and the effect of acoustic-to-electric conversion is improved. By bonding the acoustic-to-electric conversion module to the membrane hole, the stability and vibrability of the acoustic-to-electric conversion module when the sound wave vibrates are maintained.

[0018] The present invention can receive sound waves transmitted from the side, effectively overcoming the limitations of traditional sound-to-electric conversion devices. It not only supports sound waves entering in a manner parallel to the surface of the device, but also utilizes the resonance characteristics of the kazoo to improve the sound-to-electric conversion efficiency of low-frequency sound waves, and improves the practicability and integration of the device.

[0019] The kazoo-like shell not only enhances the flexibility of sound wave collection, but also helps to integrate the acoustic-to-electric conversion device into various planar electronic devices, such as smartphones and other personal electronic devices, thereby expanding the application areas of acoustic-to-electric conversion technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings: Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a schematic diagram of the exploded structure of the acoustic-electric conversion module of the present invention; Figure 3 It is a schematic diagram of the explosion structure of the shell of the present invention; Figure 4 It is a schematic diagram of the fiber morphology and acoustic and electrical properties of the present invention; Figure 5 is a schematic diagram of the relationship between the input sound pressure and the sound pressure difference of the present invention; Figure 6 It is the output power test circuit diagram of the present invention; Figure 7 is a load power variation diagram of the output power test of the present invention; Figure 8 is a capacitor charging circuit diagram of the present invention; Fig. 9 is a capacitor charging curve diagram of the present invention; Fig.10 It is a schematic diagram of the acoustic and electrical performance of the kazoo combined with traditional acoustic and electrical devices; Fig.11 is a sound pressure test curve diagram of the present invention; Fig.12 is a schematic diagram of the dimensions of the housing of the present invention; Fig.13 It is a schematic diagram of the dimensions of the first plastic film electrode or the second plastic film electrode of the present invention.

[0021] Explanation of the reference numerals: 1. Shell, 2. Sound-to-electric conversion module, 3. Air hole, 4. Membrane hole, 101. Upper cover plate, 102. Lower cover plate, 103. First pad, 104. Second pad, 201. First plastic film electrode, 202. Piezoelectric fiber film, 203. Second plastic film electrode, 204. Circular hole. DETAILED DESCRIPTION

[0022] Example 1 like Figure 1-3As shown, a kazoo-type sound-to-electric converter provided by the present invention comprises a shell 1, wherein the shell 1 is hollow and provided with a sound cavity, and air holes 3 communicating with the sound cavity are provided at both ends of the shell 1, and a membrane hole 4 is provided on the shell 1, and the membrane hole 4 is used to set a sound-to-electric conversion module 2, and the sound-to-electric conversion module 2 is used to sense sound wave signals and convert them into electrical signals; the sound-to-electric conversion module 2 comprises a first plastic film electrode 201, a piezoelectric fiber film 202, and a second plastic film electrode 203 which are arranged in contact with each other in sequence, and a circular hole 204 is provided on the first plastic film electrode 201 and the second plastic film electrode 203. A first metal conductive layer is provided on the side of the first plastic film electrode 201 which contacts the piezoelectric fiber film 202, and a second metal conductive layer is provided on the side of the second plastic film electrode 203 which contacts the piezoelectric fiber film 202, and the first metal conductive layer and the second metal conductive layer are used to be connected to external wiring terminals respectively. The shell 1 includes an upper cover plate 101 and a lower cover plate 102, and the upper cover plate 101 and the lower cover plate 102 are connected by a first pad 103 and a second pad 104, and a sound cavity is formed between the first pad 103 and the second pad 104, and the membrane hole 4 is arranged on the upper cover plate 101 or the lower cover plate 102. The first pad 103 and the second pad 104 are both inclined to form a trapezoidal sound cavity, and the trapezoidal sound cavity includes a wide end and a narrow end, the wide end is connected to the air inlet, and the narrow end is connected to the air outlet. The first plastic film electrode 201, the piezoelectric fiber film 202 and the second plastic film electrode 203 are connected by sewing with fine wires, and the circular holes 204 on the first plastic film electrode 201 and the second plastic film electrode 203 correspond to each other. The sound-to-electric conversion module 2 is bonded to the membrane hole 4 on the shell 1. The shell 1 is made of one of acrylic, wood, iron, aluminum or copper.

[0023] In this embodiment, parallel sound waves enter the interior of the kazoo-type housing 1 through the air holes 3 on the side, generate resonance in the sound cavity, thereby exciting the vibration of the piezoelectric fiber film 202 and generating electrical energy. The generated electrical energy is then transmitted to the external circuit through the first metal conductive layer and the second metal conductive layer. The present invention overcomes the defect that traditional sound-to-electric conversion equipment can only receive sound waves perpendicular to the surface of the equipment, and expands the propagation path of the sound waves and the integration of the equipment. By adopting a kazoo-type structure, sound waves can be collected parallel to the surface of the equipment, thereby overcoming the limitations of traditional equipment and improving the efficiency of sound wave collection.

[0024] In this embodiment, circular through holes are used on the first plastic film electrode 201 and the second plastic film electrode 203 to increase the core vibration area, make the vibration more obvious, and amplify the sound better, which can more effectively drive the vibration of the metal electrode to generate a larger voltage.

[0025] In this embodiment, the preparation method of the first plastic film electrode 201 or the second plastic film electrode 203 includes: using a plastic film as a substrate, coating a metal on the plastic film, and forming a first plastic film electrode 201 with a first metal electrode layer or a second plastic film electrode 203 with a second metal electrode layer. The method of coating the metal on the plastic film includes one of spraying, electroplating, or physical vapor deposition, the thickness of the plastic film is 50-150 μm, and the thickness of the first metal electrode layer or the second metal electrode layer is less than 50 nm or greater than 1000 nm. The first plastic film electrode 201 and the second plastic film electrode 203 are cut into a desired shape by a laser cutting method. In this embodiment, the shapes of the first plastic film electrode 201 and the second plastic film electrode 203 both include a square body and an elongated side ear, the length x width size of the square body is 40 mm x 30 mm, and the elongated side ear is arranged along the long side.

[0026] In this embodiment, the preparation method of the piezoelectric fiber film 202 includes: heating polyvinylidene fluoride particles (PVDF, molecular weight M) at 65° C. w =275,000) was dissolved in dimethylformamide solvent (purity of 99%) to prepare PVDF solution, acetone was added to the PVDF solution, and piezoelectric fiber film 202 was prepared by electrospinning. Specifically, a needle-shaped electrospinning device with a rotating metal drum collector (diameter 9.2 cm, length 20 cm) was used to prepare the piezoelectric fiber film 202. The prepared piezoelectric fiber film 202 was deposited on a drum collector covered with roller paper. The drum speed was set to 300rpm, and random fibers were collected to form a non-woven piezoelectric fiber film 202. The diameter of the nanofibers in the piezoelectric fiber film 202 ranged from 10nm to 5µm, and the thickness of the piezoelectric fiber film 202 ranged from 20µm to 100μm. In this embodiment, the electrospinning parameters were: the dimethylformamide solvent concentration of the spinning solution was 18%, the spinning flow rate was 1.0mL / h, the spinning distance was 10cm, the voltage was 18kV, and the drum speed was 300rpm. The diameter of the collected fibers was 432 ± 78 nm, and the fiber layer thickness was 58 ± 4 μm.

[0027] In this embodiment, the acoustic and electrical performance is best when the thickness of the piezoelectric fiber film 202 is 60 μm. Figure 4 As shown, the fiber morphology and acoustic-electric properties of the acoustic-electric converter were tested and found that under the action of 100Hz, 115dB sound waves, the open circuit voltage was 192±8.6V and the short circuit current was 12.0±1.1μA. The bandwidth of the acoustic-electric converter is 100-450Hz. The maximum output power of the acoustic-electric converter is 312.9±15.6μW, and the internal resistance is 18.8±1.3MΩ. Compared with traditional nanofiber acoustic-electric devices, the open circuit voltage of the present invention is increased by 3-5 times, and the output power is increased by nearly 2 times.

[0028] In this embodiment, the sound source is set at the entrance, and a detection point of the input sound frequency is set at the entrance, and a detection point of the output sound frequency is set at the membrane hole. The incident sound pressure amplification effect of the acousto-electric converter is tested and it is found that at a higher input sound frequency, for example, between 300 Hz and 500 Hz, the output and input sound pressure difference ∆P tends to be stable and will not fluctuate greatly with the input sound pressure, such as Figure 5 The relationship between the input sound pressure P1 and ∆P is shown in the figure. The curves from top to bottom represent the input sound frequencies of 100Hz, 150Hz, 200Hz, 250Hz, 300Hz, 350Hz, 400Hz, 450Hz, and 500Hz, respectively. However, only ∆P below 300Hz shows a positive value, while at higher sound frequencies, ∆P either fluctuates around zero (for example, 350Hz) or is negative (for example, 400-500Hz). These results confirm the frequency dependence of the sound enhancement effect of the acoustic-electric transducer and show the good amplification effect of the acoustic-electric transducer for different frequencies.

[0029] In this embodiment, Figure 6 and Figure 7 As shown, the output power of the acoustic-electric converter was tested and it was found that under noise conditions (frequency 100 Hz, sound pressure level 115 dB), the electric energy generated by the acoustic-electric converter was rectified and matched with a load resistor R of 18.8 MΩ for voltage testing, and the output power was 312.9±15.6 μW.

[0030] In this embodiment, the electric energy generated by the acoustic-electric converter can be used to drive LED lamps and charge capacitors. When the acoustic-electric converter is used to drive LED lamps, under the condition of 115dB noise (sound frequency 100Hz), the electric energy generated by the acoustic-electric device can be rectified to directly light up about 50 LEDs connected in series. When the acoustic-electric converter is used to charge capacitors, under the condition of noise (frequency 100Hz, sound pressure level 115dB), the electric energy generated by the acoustic-electric converter can be rectified to charge capacitors. The circuit diagram is as follows: Figure 8 As shown. The time to charge a 4.7μF capacitor to 10V is 7s, the time to charge a 22μF capacitor to 10V is 50s, and the time to charge a 47μF capacitor to 10V is 72s. Fig. 9 shown.

[0031] Compared with the acoustic-electric converter composed of kazoo and traditional dense piezoelectric film, the acoustic-electric converter of the present invention has better performance. For example, the acoustic-electric converter composed of kazoo and traditional dense piezoelectric film adopts a commercial piezoelectric PVDF film with a thickness of 40µm, which is sewn with two Au electrodes using fine wires and fixed on the kazoo like the piezoelectric fiber film 202 to form a kazoo acoustic-electric transducer. When the sound condition is 100Hz, 115dB, the open circuit voltage generated is 13.26±2.3V, such as Fig.10 The open circuit voltage test graph shown is much lower than the performance when using the piezoelectric fiber film 202. At the same time, unlike the piezoelectric fiber film 202, the kazoo with the commercial PVDF film only shows weak sound amplification (sound difference < 5dB) in the narrow sound frequency range of 200-250Hz in the entire sound range tested, but shows sound amplification of 100-200Hz when the sound source sound is higher than 95dB, as shown in FIG. Fig.11 The sound pressure test results are shown in the figure.

[0032] In this embodiment, Fig.12 and Fig.13 As shown, the size of the shell 1 is 11cm long, 4cm wide, and 1cm thick; the thickness of the upper cover plate 101 and the lower cover plate 102 of the plate is 0.2cm. The first pad 103 and the second pad 104 of the strip filler with a thickness of 0.6cm, a length of 9cm, and a width of 1cm are used as supports to build the internal structure. Specifically, the length x width size of the piezoelectric fiber film 202 is 40mmx 30mm, the diameter of the circular holes on the first plastic film electrode 201 and the second plastic film electrode 203 are both 2mm, and the inner diameter of the membrane hole 4 is greater than the diameter of the circular hole. The length x width size of the membrane hole 4 is 35mm x 25mm, the length x width x thickness size of the first pad 103 and the second pad 104 is 90mm x 10mm x 6mm, and the length x width x thickness size of the upper cover plate 101 and the lower cover plate 102 is 110mm x 40mm x2mm. When assembled into electronic devices such as mobile phones, the structure size of the sound-to-electric converter is about 1-4 cm, which is convenient for integration; if used as a sound generator, the device can be appropriately expanded to about 10-100 cm.

[0033] In this embodiment, the structure of the kazoo-style housing 1 utilizes the effect of sound amplification. Within a certain thickness range, the nano-piezoelectric fiber film 202 vibrates in the sound cavity. Under the reasonable size settings of the housing 1, the membrane hole 4 and the acoustic-to-electric conversion module 2, it is ensured that the maximum voltage can be generated, thereby improving the effect of acoustic-to-electric energy conversion. By bonding the acoustic-to-electric conversion module 2 to the membrane hole 4, the stability and vibrability of the acoustic-to-electric conversion module 2 during acoustic wave vibration are maintained.

[0034] The present invention significantly enhances the acoustic-electric output of low-frequency sound waves through the resonance effect of the kazoo-like structure, and expands the effectiveness of the acoustic-electric conversion technology in low-frequency application scenarios. In addition, under specific low-frequency sound wave conditions, the present invention can produce higher peak-to-peak voltage and current output, proving its efficient acoustic-electric conversion capability, and is suitable for energy collection and low-frequency signal detection. The present invention improves practicality and integration, can be integrated into planar electronic devices, and expands the scope of application.

[0035] Example 2 This embodiment is different from the above-mentioned embodiment 1 in that the piezoelectric fiber film 202 is made of fiber material by electrospinning, and the fiber material includes at least one piezoelectric polymer, and the piezoelectric polymer is polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, silk fibroin, polyhydroxybutyric acid, polyacrylonitrile, nylon-7, nylon-11, polylactic acid, polyimide, polyimide copolymer, polystyrene, polycarbonate or poly-L-lactic acid.

[0036] Example 3 This embodiment is different from the above-mentioned embodiment 2 in that the fiber material includes at least two piezoelectric polymers, and the piezoelectric fiber film 202 is made by blending at least two piezoelectric polymers, and the blending method includes blending two or more piezoelectric polymers in the same spinning solution, or dissolving different piezoelectric polymers in the spinning solution respectively. In this embodiment, the ratio of the two or more piezoelectric polymers to be blended can be adjusted arbitrarily.

[0037] Example 4 This embodiment is different from the above-mentioned embodiment 1 in that the piezoelectric fiber film 202 is made of a composite of fiber material and inorganic material, the inorganic material adopts inorganic piezoelectric material or non-piezoelectric material, the inorganic piezoelectric material includes one of zinc oxide, titanate, niobate or lead salt, the non-piezoelectric material includes lithium borosilicate polar glass ceramic and inorganic salt, the inorganic salt includes one of NaCl, KCl, Na2SO4, Na2CO3 or CaCl2.

[0038] Example 5 This embodiment is different from the above-mentioned embodiment 1 in that the piezoelectric fiber film 202 is made of a composite of multiple layers of fiber materials, and the multiple layers of fiber materials include a non-woven fabric support layer made of polyethylene terephthalate, an electrospun middle layer made of polyacrylonitrile, and a fiber layer made of cellulose.

[0039] The above are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined by the claims.

Claims

1. A kazoo-type sound-to-electric converter, characterized in that: It comprises a shell, wherein a sound cavity is hollowly arranged inside the shell, air holes connected to the sound cavity are arranged at both ends of the shell, and a membrane hole is opened on the shell, wherein the membrane hole is used to set an acoustic-electric conversion module, wherein the acoustic-electric conversion module is used to sense sound wave signals and convert them into electrical signals; the acoustic-electric conversion module comprises a first plastic film electrode, a piezoelectric fiber film and a second plastic film electrode which are contacted with each other in sequence, wherein the first plastic film electrode and the second plastic film electrode are both provided with circular holes, a first metal conductive layer is arranged on a side of the first plastic film electrode which contacts with the piezoelectric fiber film, a second metal conductive layer is arranged on a side of the second plastic film electrode which contacts with the piezoelectric fiber film, and the first metal conductive layer and the second metal conductive layer are used to be connected with external wiring terminals respectively.

2. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The shell includes an upper cover plate and a lower cover plate, the upper cover plate and the lower cover plate are connected by a first pad and a second pad, a sound cavity is formed between the first pad and the second pad, the membrane hole is arranged on the upper cover plate or the lower cover plate, the first pad and the second pad are both inclined to form a trapezoidal sound cavity, the trapezoidal sound cavity includes a wide mouth end and a narrow mouth end, the wide mouth end is connected to the air inlet, and the narrow mouth end is connected to the air outlet.

3. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The preparation method of the first plastic film electrode or the second plastic film electrode comprises: using a plastic film as a substrate, coating a metal on the plastic film to form a first plastic film electrode with a first metal electrode layer or a second plastic film electrode with a second metal electrode layer, the method of coating the metal on the plastic film comprises one of spraying, electroplating, or physical vapor deposition, the thickness of the plastic film is 50-150μm, and the thickness of the first metal electrode layer or the second metal electrode layer is less than 50nm or greater than 1000nm.

4. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The preparation method of the piezoelectric fiber film includes: dissolving polyvinylidene fluoride particles in a dimethylformamide solvent at 65°C to prepare a polyvinylidene fluoride solution, adding acetone to the polyvinylidene fluoride solution, and preparing a piezoelectric fiber film by an electrospinning method, wherein the diameter of the nanofibers in the piezoelectric fiber film ranges from 10nm to 5µm, and the thickness of the piezoelectric fiber film ranges from 20µm to 100μm.

5. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The thickness of the piezoelectric fiber film is 60 μm.

6. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The length x width dimensions of the piezoelectric fiber film are 40 mm x 30 mm, the diameters of the circular holes on the first plastic film electrode and the second plastic film electrode are both 2 mm, and the inner diameter of the film hole is larger than the circular hole diameter.

7. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The piezoelectric fiber film is made of fiber material by electrospinning, and the fiber material includes at least one piezoelectric polymer, and the piezoelectric polymer is polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, silk fibroin, polyhydroxybutyric acid, polyacrylonitrile, nylon-7, nylon-11, polylactic acid, polyimide, polyimide copolymer, polystyrene, polycarbonate or poly-L-lactic acid.

8. The kazoo-type sound-to-electric converter according to claim 7, characterized in that: The fiber material includes at least two piezoelectric polymers, and the piezoelectric fiber film is made by blending at least two piezoelectric polymers. The blending method includes blending two or more piezoelectric polymers in the same spinning solution, or dissolving different piezoelectric polymers in the spinning solution respectively.

9. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The piezoelectric fiber film is made of a composite of fiber material and inorganic material, the inorganic material is an inorganic piezoelectric material or a non-piezoelectric material, the inorganic piezoelectric material includes one of zinc oxide, titanate, niobate or plumbate, the non-piezoelectric material includes lithium borosilicate polar glass ceramics and an inorganic salt, the inorganic salt includes one of NaCl, KCl, Na2SO4, Na2CO3 or CaCl2.

10. The kazoo-type sound-to-electric converter according to claim 1, characterized in that: The piezoelectric fiber film is made of a composite of multiple fiber materials, wherein the multiple fiber materials include a non-woven fabric support layer made of polyethylene terephthalate, an electrospun middle layer made of polyacrylonitrile, and a fiber layer made of cellulose.

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