An ultrasonic sensor suitable for use in underwater environments

Abstract

The utility model relates to ultrasonic sensor technical field, especially in kind suitable for underwater environment's ultrasonic sensor, including outside matching layer, inside matching layer and piezoelectric ceramic: one side of outside matching layer is provided with recessed cavity, inside matching layer sets up in recessed cavity, and is pasted in the chamber bottom of recessed cavity, and the acoustic impedance of outside matching layer is less than the acoustic impedance of inside matching layer, piezoelectric ceramic sets up in recessed cavity, piezoelectric ceramic is connected in the one side of inside matching layer far from the chamber bottom of recessed cavity, and piezoelectric ceramic is annular structure, the ultrasonic sensor suitable for underwater environment of the application, and the double -deck matching layer structure formed through outside matching layer and inside matching layer improves acoustic matching performance, and cooperation annular piezoelectric ceramic reduces radial frequency constant, realizes low resonant frequency under small size, and increases beam angle, to improve the performance of sensor in underwater communication all -round, solve the sound energy loss big, size limited and the problem such as small communication angle of prior art.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic sensor technology, and in particular to an ultrasonic sensor suitable for underwater environments. Background Technology

[0002] With the continuous development of intelligent devices, pool robots have been widely used in pool cleaning and monitoring. However, due to the strong attenuation of electromagnetic waves by water, pool robots cannot directly interconnect with wireless networks underwater, greatly limiting their intelligence and remote control capabilities. Currently, although some underwater communication methods exist, they generally suffer from problems such as short communication distance and susceptibility to signal interference, making it difficult to meet the stable communication requirements of pool robots in complex underwater environments. Therefore, developing an efficient, stable, and wide-range underwater communication sensor is of significant practical importance to solve the problems of high sound energy loss, size limitations, and narrow communication angles in existing technologies. Utility Model Content

[0003] This invention addresses the shortcomings of existing underwater communication methods, such as high sound energy loss, size limitations, and narrow communication angles, by providing an ultrasonic sensor suitable for underwater environments.

[0004] In a first aspect, this utility model provides an ultrasonic sensor suitable for underwater environments, comprising: An outer matching layer, wherein a cavity is provided on one side of the outer matching layer; An inner matching layer is disposed within the cavity and fits against the bottom of the cavity; the acoustic impedance of the outer matching layer is less than that of the inner matching layer. A piezoelectric ceramic is disposed within the cavity, and the piezoelectric ceramic is connected to the inner matching layer on the side away from the bottom of the cavity. The piezoelectric ceramic has a ring-shaped structure.

[0005] The ultrasonic sensor described in this application, suitable for underwater environments, improves acoustic matching performance through a double-layer matching layer structure formed by an outer matching layer and an inner matching layer. Combined with an annular piezoelectric ceramic to reduce the radial frequency constant, it achieves a low resonant frequency in a smaller size and increases the beam angle, thereby comprehensively improving the sensor's performance in underwater communication and solving the problems of high acoustic energy loss, size limitation, and small communication angle in existing technologies.

[0006] Preferably, the outer matching layer serves as the housing of the ultrasonic sensor.

[0007] Preferably, the outer matching layer includes an end shell portion and an annular side shell portion integrally formed from the same material. The end shell portion closes one end of the annular side shell portion, and the end shell portion and the annular side shell portion form the cavity. The inner matching layer is attached to the end shell portion.

[0008] Preferably, the thickness of the inner matching layer is thinner than the thickness of the end shell. The thickness of the inner matching layer and the thickness of the end shell are related to their own sound velocity and sensor frequency; this design yields better results.

[0009] Preferably, the thickness of the inner matching layer is 1mm-15mm.

[0010] Preferably, the thickness of the end shell portion is 1mm-10mm.

[0011] Preferably, the acoustic impedance range of the outer matching layer is 2Mrayl-6Mrayl.

[0012] Preferably, the acoustic impedance range of the inner matching layer is 6Mrayl-15Mrayl.

[0013] Preferably, the inner side of the end shell portion has a protrusion protruding into the concave cavity, and the protrusion penetrates the inner matching layer and comes into contact with the piezoelectric ceramic.

[0014] When the inner matching layer is formed by potting, the uncured matching layer is first potted inside the outer matching layer, then the piezoelectric ceramic is covered on top, and then the inner matching layer is cured. The purpose of the protrusion is to limit the piezoelectric ceramic during the curing process to ensure the thickness of the inner matching layer after curing.

[0015] More preferably, the protrusion includes a plurality of circumferentially spaced protrusions, the protrusions being connected to the outer matching layer.

[0016] More preferably, the protrusion has a ring-shaped structure and is connected to the outer matching layer.

[0017] Preferably, the protrusion extends through the inner matching layer.

[0018] Preferably, the cavity is further filled with a backing adhesive layer and a potting adhesive layer, wherein the potting adhesive layer is located on the side of the backing adhesive layer away from the piezoelectric ceramic.

[0019] Preferably, the ultrasonic sensor is used for underwater communication.

[0020] Preferably, the piezoelectric ceramic has an acoustic impedance of Z1, water has an acoustic impedance of Z3, the inner matching layer has an acoustic impedance of Z2, and the outer matching layer has an acoustic impedance of Z4. .

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows: The ultrasonic sensor described in this application, suitable for underwater environments, improves acoustic matching performance through a double-layer matching layer structure formed by an outer matching layer and an inner matching layer. Combined with an annular piezoelectric ceramic to reduce the radial frequency constant, it achieves a low resonant frequency in a smaller size and increases the beam angle, thereby comprehensively improving the sensor's performance in underwater communication and solving the problems of high acoustic energy loss, size limitation, and small communication angle in existing technologies. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the overall structure of an ultrasonic sensor suitable for underwater environments according to this application.

[0023] Figure 2 This is a schematic diagram of the fit between the piezoelectric ceramic and the inner matching layer in this application.

[0024] Figure 3 This is a cross-sectional view of the outer matching layer of this application.

[0025] Figure 4 This is a cross-sectional view of the piezoelectric ceramic, inner matching layer, and outer matching layer of this application.

[0026] Figure 5 This is a three-dimensional structural schematic diagram of the outer matching layer of this application.

[0027] Figure 6 This is a cross-sectional view of the outer matching layer of this application (the protrusion is a ring structure and is connected to the end shell).

[0028] Figure 7 This is a three-dimensional structural diagram of the outer matching layer of this application (the protrusion has a ring structure and is connected to the end shell).

[0029] Figure 8 This is a cross-sectional view of the outer matching layer of this application (the protrusion is a ring structure, and the protrusion is connected to both the end shell and the ring side shell).

[0030] Figure 9 This is a three-dimensional structural diagram of the outer matching layer of this application (the protrusion is a ring structure, and the protrusion is connected to both the end shell and the ring side shell). Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0032] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0033] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0034] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0035] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0036] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0037] Example The ultrasonic sensor for underwater communication described in this application includes: an outer matching layer 6, an inner matching layer 5 attached to the inner side of the outer matching layer 6, and a piezoelectric ceramic 4 attached to the inner side of the inner matching layer 5.

[0038] In a preferred embodiment, the inner matching layer 5 is located between the outer matching layer 6 and the piezoelectric ceramic 4.

[0039] The piezoelectric ceramic 4 preferably has a sheet structure, also known as piezoelectric ceramic 4-sheet.

[0040] In a preferred embodiment, a cavity 63 is provided on one side of the outer matching layer 6; In a preferred embodiment, the inner matching layer 5 is disposed within the cavity 63 and is attached to the bottom of the cavity 63.

[0041] In a preferred embodiment, the acoustic impedance of the outer matching layer 6 is less than that of the inner matching layer 5. In a preferred embodiment, a piezoelectric ceramic 4 is disposed within the cavity 63, and the piezoelectric ceramic 4 is connected to the inner matching layer 5 on the side away from the bottom of the cavity 63.

[0042] In a preferred embodiment, the piezoelectric ceramic 4 has a ring-shaped structure.

[0043] In a preferred embodiment, the outer matching layer 6 serves as the housing of the ultrasonic sensor.

[0044] In a further preferred embodiment, the outer matching layer 6 includes an end shell portion 61 and an annular side shell portion 62 made of the same material and integrally formed. The end shell portion 61 closes one end of the annular side shell portion 62, and the end shell portion 61 and the annular side shell portion 62 form the cavity 63. The inner matching layer 5 is attached to the end shell portion 61.

[0045] In a preferred embodiment, the inner matching layer 5 is thinner than the end shell portion 61.

[0046] In a preferred embodiment, the thickness of the inner matching layer 5 is 1mm-15mm; In a preferred embodiment, the thickness of the end shell portion 61 is 1mm-10mm.

[0047] In a preferred embodiment, the acoustic impedance of the outer matching layer 6 is in the range of 2Mrayl-6Mrayl.

[0048] In a preferred embodiment, the acoustic impedance of the inner matching layer 5 is in the range of 6Mrayl-15Mrayl.

[0049] In a preferred embodiment, a protrusion 64 is provided on the inner side of the end shell 61 protruding into the cavity 63, and the protrusion 64 penetrates the inner matching layer 5 and comes into contact with the piezoelectric ceramic 4.

[0050] When the inner matching layer 5 is formed by potting, the uncured matching layer is first potted inside the outer matching layer 6, and then the piezoelectric ceramic 4 is covered on top. Then the inner matching layer 5 is cured and formed. The purpose of the protrusion 64 is to limit the piezoelectric ceramic 4 during the curing process to ensure the thickness of the inner matching layer 5 after curing.

[0051] like Figure 4 and 5 As shown, more preferably, the protrusion 64 includes a plurality of circumferentially spaced protrusions, which are connected to the outer matching layer 6.

[0052] More preferably, the boss can be connected to at least one of the end shell portion 61 and the annular side shell portion 62.

[0053] like Figure 6-9 As shown, more preferably, the protrusion 64 has an annular structure and is connected to the outer matching layer 6.

[0054] More preferably, the protrusion 64 may be connected to at least one of the end shell portion 61 and the annular side shell portion 62.

[0055] like Figure 4 As shown, in a preferred embodiment, the protrusion 64 penetrates the inner matching layer 5.

[0056] In a preferred embodiment, the cavity 63 is further filled with a backing adhesive layer 3 and a potting adhesive layer 2, wherein the potting adhesive layer 2 is located on the side of the backing adhesive layer 3 away from the piezoelectric ceramic 4.

[0057] In one preferred embodiment, the ultrasonic sensor is used for underwater communication.

[0058] The ultrasonic sensor described in this embodiment, suitable for underwater environments, improves acoustic matching performance through a double-layer matching layer structure formed by an outer matching layer 6 and an inner matching layer 5. Combined with an annular piezoelectric ceramic 4, it reduces the radial frequency constant, achieves a lower resonant frequency in a smaller size, and increases the beam angle, thereby comprehensively improving the sensor's performance in underwater communication and solving the problems of high acoustic energy loss, size limitation, and small communication angle in existing technologies.

[0059] The smaller size mentioned above refers to the reduction in size of the annular piezoelectric ceramic 4 compared to the traditional circular piezoelectric ceramic, for example, a reduction of 10%-30% in diameter compared to the traditional circular piezoelectric ceramic.

[0060] In a preferred embodiment, a protrusion 64 is provided on the inner side of the end shell 61 protruding into the cavity 63, and the protrusion 64 penetrates the inner matching layer 5 and comes into contact with the piezoelectric ceramic 4.

[0061] When the inner matching layer 5 is formed by potting, the uncured matching layer is first potted inside the outer matching layer 6, and then the piezoelectric ceramic 4 is covered on top. Then the inner matching layer 5 is cured and formed. The purpose of the protrusion 64 is to limit the piezoelectric ceramic 4 during the curing process to ensure the thickness of the inner matching layer 5 after curing.

[0062] Principle of dual-layer matching design: According to acoustic theory, when sound waves propagate in different media, if the acoustic impedances of the two media differ significantly, large reflections will occur, leading to energy loss. In underwater piezoelectric ultrasonic sensors, the acoustic impedance of the piezoelectric ceramic 4 is much higher than that of water. The purpose of the double-layer matching layer design is to construct at least two acoustic impedance transition layers between the piezoelectric ceramic 4 and the water. This allows the sound wave, starting from the piezoelectric ceramic 4, to undergo initial acoustic impedance adjustment upon passing through the inner matching layer 5, and further adjustment through the outer matching layer 6, ultimately bringing the acoustic impedance closer to that of the water medium. This improves the transmittance of the sound wave, reduces reflections, and achieves efficient sound energy transmission. For example, assuming the acoustic impedance of the piezoelectric ceramic 4 is Z1, the acoustic impedance of the water is Z3, the acoustic impedance of the inner matching layer 5 is Z2, and the acoustic impedance of the outer matching layer 6 is Z4, ideally, this can... This is how acoustic impedance matching is gradually achieved.

[0063] At a specific frequency, the optimal acoustic impedance matching effect is achieved when the thickness of the matching layer is one-quarter of the wavelength of the sound wave in the medium. For a double matching layer, the corresponding one-quarter wavelength thickness is calculated and designed based on the sound velocity in the materials of the inner matching layer 5 and the outer matching layer 6, as well as the operating frequency of the sensor. Thus, when the sound wave propagates from the piezoelectric ceramic 4 to the matching layer, reflected waves are generated at the two interfaces of the matching layer. These two reflected waves will interfere and cancel each other out under certain conditions, thereby further reducing reflected energy and enhancing transmitted energy. For example, for a sound wave with frequency f, in the matching layer material with a sound velocity v, the wavelength λ = v / f, then the matching layer thickness d = λ / 4 = v / (4f).

[0064] Inner matching layer 5: This layer is made of a material with high acoustic impedance, such as an epoxy resin-based composite material doped with tungsten powder or metal compounds. Its acoustic impedance differs significantly from that of water, but it effectively facilitates the initial transition of sound waves emitted from the piezoelectric layer with higher acoustic impedance inside the sensor, reducing sound wave reflection on the sensor surface. By precisely controlling its thickness and calculating according to acoustic matching theory formulas, it satisfies the quarter-wavelength matching principle at a specific frequency, thus initially optimizing the sound energy transmission efficiency.

[0065] Outer matching layer 6: Made of low acoustic impedance materials, such as polymer materials or epoxy resin composites. This layer is located between the inner matching layer 5 and the water, further adjusting the acoustic impedance to achieve a smooth transition from the inner matching layer 5 to the water. The thickness is also precisely controlled according to acoustic principles to ensure that the entire double-layer matching layer structure effectively reduces acoustic energy transmission loss over a wide frequency range, resulting in improved acoustic energy transmission efficiency compared to traditional single-layer matching layers.

[0066] Applications of cyclic piezoelectric ceramics 4 Structural Design: A ring-shaped piezoelectric ceramic 4 is used as the core piezoelectric element. Compared to traditional block piezoelectric ceramics 4, the ring structure has unique vibration characteristics. The ratio of its inner diameter to its outer diameter is carefully designed, and the dimensional parameters are precisely determined based on the radial vibration frequency calculation formula and the target resonant frequency. Through this design, the radial frequency constant of the ring-shaped piezoelectric ceramic 4 is reduced, achieving a lower resonant frequency with a smaller outer diameter.

[0067] Under the thin circular ring approximation, the formula for calculating the lowest fundamental frequency of the radial vibration of the toroidal piezoelectric ceramic is: .

[0068] in, f r It is the radial frequency; r m The average radius of the ring r m =r 1+ r 2 / 2, r 1 is the outer radius of the annulus. r 2 is the inner radius of the ring; E is the elastic modulus of the piezoelectric ceramic material, which reflects the material's ability to resist elastic deformation. ρ It is the density of the material; μ It is Poisson's ratio of the material, representing the ratio of transverse strain to longitudinal strain.

[0069] Working principle: When an electrical signal is applied to the electrodes of the annular piezoelectric ceramic 4, its special structure generates radial vibration, which in turn emits ultrasonic waves. When receiving ultrasonic waves, the external sound waves cause radial vibration of the annular piezoelectric ceramic 4, thereby generating an electrical signal on the electrodes. This structural design allows the sensor to couple to a lower resonant frequency within a smaller physical size, creating conditions for increasing the beam angle.

[0070] Achieving increased beam angle Based on the relationship between frequency and beam angle: According to acoustic theory, the beam angle of a sensor is inversely proportional to its resonant frequency. By employing the aforementioned annular piezoelectric ceramic 4 to achieve a lower resonant frequency, the beam angle can be increased under the same conditions. In some examples, the -3dB beam angle obtained by using a 28mm diameter shell with a traditional 25mm circular piezoelectric ceramic 4 is approximately 60°, but the -3dB beam angle obtained by using the same 28mm diameter shell with an annular piezoelectric ceramic 4 (25mm outer diameter, 10mm inner diameter) is approximately 80°, significantly widening the communication angle and reducing communication dead zones.

[0071] Structural optimization assistance: In addition to frequency factors, this application also optimizes the overall structure of the sensor. The design of the double-layer matching layer not only improves the acoustic matching performance, but its specific structural shape also affects the radiation direction of the sound waves, further assisting in increasing the beam angle, enabling the sensor to achieve signal transmission and reception over a wider angle underwater.

[0072] Three beneficial effects Improved acoustic matching performance: The dual-layer matching structure effectively reduces the acoustic impedance mismatch between the sensor and seawater, significantly improves acoustic energy transmission efficiency, enhances signal transmission strength and reception sensitivity, and lays the foundation for stable and efficient underwater communication.

[0073] Achieving a combination of small size and low resonant frequency: The application of the annular piezoelectric ceramic 4 breaks the limitations of traditional sensor size and resonant frequency, enabling the coupling of lower resonant frequencies within a smaller sensor size. This meets the miniaturization requirements of underwater equipment and also provides the possibility of increasing the beam angle. In some examples, the radial resonant frequency of a traditional disc-type piezoelectric ceramic 4 with a diameter of 25mm is 80kHz, while the radial resonant frequency of an annular piezoelectric ceramic 4 with the same diameter and made of the same material (i.e., an outer diameter of 25mm and an inner diameter of 10mm) is 60kHz.

[0074] Material preparation Preparation of inner matching layer 5 material: An appropriate amount of metal powder or metal compound powder is added to epoxy resin and thoroughly mixed using a high-speed stirring device. Then, a curing agent is added, and stirring continues. The mixed material is poured into a specific mold and cured under certain temperature and pressure to form the inner matching layer 5 material with a predetermined thickness and shape.

[0075] Material preparation of outer matching layer 6: The outer matching layer 6 is manufactured using machining or injection molding processes according to a predetermined thickness and shape, taking into account the outer shell structure. Preparation of cyclic piezoelectric ceramic 4: Suitable raw materials for piezoelectric ceramic 4, such as lead zirconate titanate (PZT)-based materials, are selected. Cyclic green bodies are prepared through processes such as batching, ball milling, and molding, and then sintered in a high-temperature furnace to obtain cyclic piezoelectric ceramic 4 with specific properties. The electrodes are then coated and sintered to meet electrical performance requirements.

[0076] The ultrasonic sensor described in this application is also called an ultrasonic piezoelectric sensor or a piezoelectric ultrasonic sensor.

[0077] Ultrasonic sensor assembly: First, the prepared inner matching layer 5 is installed on the inner side of the outer matching layer 6, and a special adhesive is used to ensure that the two are tightly bonded.

[0078] Next, the positive and negative electrodes of the ring piezoelectric ceramic 4 are connected using electrode wire 1.

[0079] Furthermore, the annular piezoelectric ceramic 4 is installed on the inner side of the inner matching layer 5, and a special adhesive is used to ensure that the two are tightly bonded.

[0080] After the adhesive has cured, a backing layer is potted on the back of the sensor, using sound-absorbing materials such as rubber-based sound-absorbing composites to reduce sound wave reflection.

[0081] Finally, waterproof potting compound is applied to the backing layer to ensure the sensor's waterproof performance and complete the sensor assembly.

[0082] Performance testing and optimization: The assembled sensor was placed in a test tank simulating an underwater environment, and its performance in transmitting and receiving ultrasonic signals was tested using professional acoustic testing equipment. Parameters such as transmitted signal strength, received sensitivity, resonant frequency, and beam angle were measured.

[0083] Optimization and adjustments were made based on the test results. If the acoustic energy transmission efficiency did not meet expectations, the thickness or material ratio of the double-layer matching layer could be fine-tuned; if the resonant frequency deviated from the target value, the dimensional accuracy of the annular piezoelectric ceramic 4 was checked and necessary corrections were made; if the beam angle was not ideal, the overall structural design of the sensor was further optimized. Through multiple tests and optimizations, the sensor performance was brought to its optimal state.

[0084] In summary, this invention aims to design an ultrasonic sensor suitable for underwater environments. By using an innovative double-layer matching structure to improve acoustic matching performance, and by utilizing annular piezoelectric ceramics to reduce the radial frequency constant, a low resonant frequency can be achieved in a small size, and the beam angle can be increased. This comprehensively improves the sensor's performance in underwater communication and solves the problems of high acoustic energy loss, size limitation, and small communication angle in existing technologies.

[0085] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An ultrasonic sensor suitable for underwater environments, characterized in that, include: An outer matching layer (6) is provided with a cavity (63) on one side. The inner matching layer (5) is disposed in the cavity (63) and fits against the bottom of the cavity (63). The acoustic impedance of the outer matching layer (6) is less than that of the inner matching layer (5). A piezoelectric ceramic (4) is disposed in the cavity (63). The piezoelectric ceramic (4) is connected to the inner matching layer (5) on the side away from the bottom of the cavity (63). The piezoelectric ceramic (4) has a ring structure.

2. The ultrasonic sensor suitable for underwater environments according to claim 1, characterized in that, The outer matching layer (6) serves as the housing of the ultrasonic sensor.

3. The ultrasonic sensor suitable for underwater environments according to claim 1, characterized in that, The outer matching layer (6) includes an end shell portion (61) and an annular side shell portion (62) made of the same material and integrally formed. The end shell portion (61) closes one end of the annular side shell portion (62). The end shell portion (61) and the annular side shell portion (62) form the cavity (63). The inner matching layer (5) is attached to the end shell portion (61).

4. An ultrasonic sensor suitable for underwater environments according to claim 3, characterized in that, The thickness of the inner matching layer (5) is thinner than the thickness of the end shell portion (61).

5. An ultrasonic sensor suitable for underwater environments according to claim 3, characterized in that, The thickness of the inner matching layer (5) is 1mm-15mm; And / or, The thickness of the end shell (61) is 1mm-10mm; And / or, The acoustic impedance range of the outer matching layer (6) is 2Mrayl-6Mrayl; And / or, The acoustic impedance range of the inner matching layer (5) is 6Mrayl-15Mrayl.

6. An ultrasonic sensor suitable for underwater environments according to claim 3, characterized in that, The end shell (61) has a protrusion (64) protruding into the cavity (63) on the inner side, and the protrusion (64) is in support contact with the piezoelectric ceramic (4).

7. An ultrasonic sensor suitable for underwater environments according to claim 6, characterized in that, The protrusion (64) penetrates the inner matching layer (5).

8. An ultrasonic sensor suitable for underwater environments according to claim 6, characterized in that, The protrusion (64) includes a plurality of circumferentially spaced protrusions, which are connected to the outer matching layer (6).

9. An ultrasonic sensor suitable for underwater environments according to claim 6, characterized in that, The protrusion (64) has a ring structure and is connected to the outer matching layer (6).

10. An ultrasonic sensor suitable for underwater environments according to any one of claims 1-6, characterized in that, The cavity (63) is also filled with a backing adhesive layer (3) and a potting adhesive layer (2), with the potting adhesive layer (2) located on the side of the backing adhesive layer (3) away from the piezoelectric ceramic (4); The ultrasonic sensor is used for underwater communication; The acoustic impedance of the piezoelectric ceramic (4) is Z1, the acoustic impedance of water is Z3, the acoustic impedance of the inner matching layer (5) is Z2, and the acoustic impedance of the outer matching layer (6) is Z4. 。

Images