Ultrasonic transducer

Abstract

The present invention discloses an ultrasonic transducer. The ultrasonic transducer comprises: a shell, a cavity is arranged inside the shell, at least one ultrasonic transmitting unit for transmitting ultrasonic waves is arranged on the inner surface of the shell, the ultrasonic transmitting unit has the function of reflecting ultrasonic waves, and the cavity is a resonant cavity; the ultrasonic waves emitted by the ultrasonic transmitting unit and the reflected waves formed by the ultrasonic transmitting unit reflecting the ultrasonic waves are focused on the focal area of ​​the ultrasonic transmitting unit. The ultrasonic transducer provided by the present invention realizes resonant focusing and can withstand high hydrostatic pressure, thereby further improving the sound pressure in the focal area.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic technology, and in particular to an ultrasonic transducer. Background Art

[0002] After ultrasound is focused, an area with highly concentrated energy can be obtained, which is called the focal zone. Using this feature, China has taken the lead in developing this technology into high-intensity focused ultrasound tumor treatment equipment, and has applied it to the clinical treatment of benign and malignant tumors such as liver tumors, kidney tumors, bone tumors, and uterine fibroids, achieving good results in terms of treatment safety, effectiveness, and economy, and gradually forming a new minimally invasive treatment technology direction.

[0003] Existing ultrasonic focusing methods, such as spherical shell focusing, lens focusing, reflector focusing, phased focusing, etc., are all traveling wave focusing methods. The highest sound pressure achieved by the traveling wave focusing method is 10 7 Pa order of magnitude (continuous wave), the minimum focal size is of the wavelength order, so the focal energy is difficult to further increase.

[0004] However, in the prior art, there is no ultrasonic transducer that can further increase the focal sound pressure. Summary of the invention

[0005] The present invention provides an ultrasonic transducer for further improving the sound pressure in a focal region.

[0006] To achieve the above object, the present invention provides an ultrasonic transducer, comprising: a housing, a cavity is arranged inside the housing, at least one ultrasonic transmitting unit for transmitting ultrasonic waves is arranged on the inner surface of the housing, the ultrasonic transmitting unit has the function of reflecting ultrasonic waves, and the cavity is a resonance cavity;

[0007] The ultrasonic wave emitted by the ultrasonic transmitting unit and the reflected wave formed by the ultrasonic wave reflected by the ultrasonic transmitting unit are focused on the focal area of ​​the ultrasonic transmitting unit.

[0008] Optionally, the shape of the cavity is a spherical shell or a truncated spherical shell including the center of the sphere, and the focal area of ​​the ultrasonic transmitting unit is the center position of the cavity.

[0009] Optionally, the shell is made of aluminum alloy or steel.

[0010] Optionally, there are multiple ultrasonic transmitting units, and each ultrasonic transmitting unit is a piezoelectric array element.

[0011] Optionally, an electrode protection layer is provided on the inner surface of the ultrasonic transmitting unit.

[0012] Optionally, a matching layer is provided on the inner surface of the ultrasound transmitting unit.

[0013] Optionally, the operating frequency of the ultrasonic transmitting unit is 400kHz to 1200kHz.

[0014] Optionally, the ultrasonic transducer can withstand a hydrostatic pressure greater than or equal to 10 MPa.

[0015] Optionally, the thickness of the shell is 20 mm to 50 mm.

[0016] The present invention has the following beneficial effects:

[0017] In the technical solution of the ultrasonic transducer provided by the present invention, the ultrasonic transducer includes a shell, a cavity is arranged inside the shell, and at least one ultrasonic transmitting unit is arranged on the inner surface of the shell. The ultrasonic transducer provided by the present invention realizes resonant focusing and can withstand high hydrostatic pressure, thereby further improving the sound pressure in the focal area. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of an ultrasonic transducer provided in Embodiment 1 of the present invention;

[0019] Figure 2 Schematic diagram of sound wave propagation. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the ultrasonic transducer provided by the present invention is described in detail below with reference to the accompanying drawings.

[0021] Figure 1 A schematic diagram of the structure of an ultrasonic transducer provided in Embodiment 1 of the present invention is shown in FIG. Figure 1 As shown, the ultrasonic transducer includes: a shell 1, a cavity 2 is arranged inside the shell 1, and at least one ultrasonic transmitting unit 3 for transmitting ultrasonic waves is arranged on the inner surface of the shell 1. The ultrasonic transmitting unit 3 has the function of reflecting ultrasonic waves, and the cavity 2 is a resonance cavity; the ultrasonic waves emitted by the ultrasonic transmitting unit 3 and the reflected waves formed by the ultrasonic transmitting unit 3 reflecting the ultrasonic waves are focused on the focal area of ​​the ultrasonic transmitting unit 3.

[0022] The shell 1 has a hollow structure formed inside, which is the cavity 2. The surface of the cavity 2 is the inner surface of the shell 1, and the ultrasonic transmitting unit 3 is located in the cavity 2 and is arranged on the inner surface of the shell 1.

[0023] The housing 1 is a support body of the ultrasonic transducer and also serves as a shell of the ultrasonic transducer. Preferably, the housing 1 is made of aluminum alloy or steel, so that the ultrasonic transducer has good rigidity, thereby increasing the high static pressure that the ultrasonic transducer can withstand.

[0024] The ultrasonic wave emitted by the ultrasonic transmitting unit 3 propagates to the focal area, and after passing through the focal area, continues to propagate to the inner surface of the ultrasonic transmitting unit 3 , forming a reflected wave on the inner surface of the ultrasonic transmitting unit 3 .

[0025] Preferably, the shape of the cavity 2 is a spherical shell or a truncated spherical shell including the center of the sphere, and the focal area of ​​the ultrasonic transmitting unit 3 is the center position of the transducer housing 2. In this embodiment, the shape of the cavity 2 is a truncated spherical shell including the center of the sphere, specifically, the shape of the cavity 2 is a spherical table, for example, the shape of the cavity 2 is a drum. In practical applications, the shape of the cavity 2 can also be other shapes, which are not listed here one by one.

[0026] Figure 2 is a schematic diagram of sound wave propagation, such as Figure 2 As shown, the ultrasonic wave emitted by the ultrasonic transmitting unit 3 propagates to the spherical center position O, and then continues to propagate to the inner surface of the ultrasonic transmitting unit 3 after passing through the spherical center position O, and then forms a reflected wave through reflection from the inner surface of the ultrasonic transmitting unit 3. When the cavity 2 meets the resonance condition, that is, when the cavity 2 forms a resonance cavity, the ultrasonic wave directly focused at the spherical center position O and the reflected wave have the same phase, so that a superposition of sound waves can be formed at the spherical center position O, so that a high-intensity stable sound field distribution is formed in the resonance cavity, so that a high sound pressure is reached at the spherical center position O, thereby increasing the sound pressure in the focal area.

[0027] The ultrasonic transmitting unit 3 is located on the inner surface of the shell 1. Specifically, multiple ultrasonic transmitting units 3 can be pasted on the inner surface of the shell 1. The outer surface of the ultrasonic transmitting unit 3 faces the shell 1, and the outer surface of the ultrasonic transmitting unit 3 can be pasted to the inner surface of the shell 1. Preferably, the number of ultrasonic transmitting units 3 is multiple, and the ultrasonic transmitting unit 3 is a piezoelectric array element. For example, the material of the piezoelectric array element is piezoelectric ceramic or 1-3 type piezoelectric composite material. Multiple ultrasonic transmitting units 3 adopt an array element combined structure. In this embodiment, the parameters of the piezoelectric array element can be designed according to the shape of the cavity 2 and the focusing requirements. The influence of the number and arrangement of the piezoelectric array elements on the focusing performance and sound pressure can be studied by numerical simulation. The results show that the sound pressure at the focal area (center position O) is proportional to the number of piezoelectric array elements. Multiple piezoelectric array elements are arranged on the surface of the cavity 2 in sequence. Preferably, multiple piezoelectric array elements are arranged on the surface of the cavity 2 in a closely spaced manner, which is conducive to the suppression of the side lobes of the ultrasonic wave. In addition, the vibration mode of the piezoelectric array element adopts the thickness vibration mode to improve its electroacoustic conversion efficiency.

[0028] Optionally, the inner surface of the ultrasonic transmitting unit 3 may be provided with an electrode protection layer (not specifically shown in the figure). Preferably, the material of the electrode protection layer is nickel or a non-metallic material. If the inner surface of the ultrasonic transmitting unit 3 is a negative electrode, the negative electrode of the ultrasonic transmitting unit 3 may be chemically plated with nickel or a non-metallic material to form an electrode protection layer. The manufacturing process of the above-mentioned electrode protection layer may be performed before the ultrasonic transmitting unit 3 is arranged on the inner surface of the housing 1, and the process of forming the electrode protection layer is a process of pre-treating the ultrasonic transmitting unit 3. The electrode protection layer can protect the electrode of the ultrasonic transmitting unit 3.

[0029] Optionally, a matching layer (not specifically shown in the figure) may be provided on the inner surface of the ultrasonic transmitting unit 3. Preferably, the material of the matching layer is a polymer material. The inner surface of the ultrasonic transmitting unit 3 is a cathode, and a polymer material layer may be made on the cathode of the ultrasonic transmitting unit 3. The process of making the above matching layer may be performed before the ultrasonic transmitting unit 3 is arranged on the inner surface of the housing 1, and the process of forming the matching layer is the process of pre-treating the ultrasonic transmitting unit 3. The matching layer is an important component of the ultrasonic transducer. The function of the matching layer is to match the acoustic impedance difference between the ultrasonic transmitting unit and the medium (such as water) of the ultrasonic transducer, and to achieve acoustic impedance matching or transition, so that the acoustic energy transmittance between the ultrasonic transmitting unit and the medium water is greatly improved. At the same time, the bandwidth of the ultrasonic transducer can be widened, so that the acoustic wave energy utilization rate of the transducer is improved, and the performance is improved. For a given frequency, the thickness of the matching layer is 1 / 4λ in principle, but the thickness will be corrected according to the experimental data of the ultrasonic transducer. The method is to first simulate and design according to the bandwidth and electroacoustic conversion efficiency of the ultrasonic transducer, and then determine the thickness of the matching layer according to the experimental results. In this embodiment, the matching layer is provided to enable better transmission of ultrasonic waves and to improve the reflectivity of reflected waves.

[0030] Furthermore, the ultrasonic transducer further comprises: an upper end cover 4 and a lower end cover 5. The upper end cover 4 is located above the cavity 2 and is mounted on the housing 1; the lower end cover 5 is located below the cavity 2 and is mounted on the housing 1.

[0031] Further, the ultrasonic transducer includes: a connection seat 6 and a power aviation plug connector 7. Preferably, the connection seat 6 is a pressure-resistant connection seat, and the power aviation plug connector 7 is a pressure-resistant power aviation plug connector. The connection seat 6 and the power aviation plug connector 7 both adopt a watertight joint and an integrated vulcanized cable method, and the sealing method adopts a sealing ring sealing and a rubber vulcanization sealing process. Double sealing is adopted for the installation surface of the connection seat 6 and the power aviation plug connector 7, and at the same time, each electrical connection and each core adopts a quadruple sealing ring sealing. After each set of connection seat 6 and power aviation plug connector 7 is manufactured, a rubber fully sealed vulcanization process is adopted for the tail of each connection seat 6 and power aviation plug connector 7 to ensure that the hydrostatic pressure that can be tolerated is ≥10MPa. When installing the connection seat 6 and the power aviation plug connector 7, apply special pressure-resistant sealing grease to ensure sealing and pressure resistance indicators. At the same time, the connecting cable of the connection seat 6 and the power aviation plug connector 7 is a specially customized cable that meets the pressure resistance requirements. After each set of cables is manufactured, strict pressure resistance tests and related technical indicators are tested.

[0032] In this embodiment, the width of the cavity 2 is 200 mm to 1000 mm. For example, when the shape of the cavity 2 is a spherical shell or a spherical shell including the center of the sphere, the diameter of the cavity 2 is 200 mm to 1000 mm.

[0033] In this embodiment, the operating frequency of the ultrasonic transmitting unit 3 is 400 kHz to 1200 kHz.

[0034] In this embodiment, the hydrostatic pressure that the ultrasonic transducer can withstand is greater than or equal to 10 MPa. The ultrasonic transducer has the characteristics of high hydrostatic pressure resistance, thereby achieving the purpose of suppressing medium cavitation and increasing the cavitation threshold. The ultrasonic transducer in this embodiment can be used in deep water, pressurized or normal pressure environments.

[0035] In this embodiment, the sound pressure in the focal area is greater than or equal to 10 9 Pa.

[0036] In this embodiment, the thickness of the housing 1 is 20 mm to 50 mm.

[0037] In the technical solution of the ultrasonic transducer provided in this embodiment, the ultrasonic transducer includes a shell, a cavity is arranged inside the shell, and at least one ultrasonic transmitting unit is arranged on the inner surface of the shell. The ultrasonic transducer provided in this embodiment realizes resonant focusing and can withstand high hydrostatic pressure, thereby further improving the sound pressure in the focal area. The ultrasonic transducer in this embodiment can form the basic structure of the ultrasonic transducer by arranging a cavity inside the shell and an ultrasonic transmitting unit on the inner surface of the shell. The process difficulty and processing requirements are low, which facilitates implementation and reduces costs. The inner surface of the shell of the present invention is both an ultrasonic transmitting surface and a reflecting surface of sound waves. The resonance focusing of sound waves is realized through ultrasonic transducer frequency tracking and compensation, phase control, ultrasonic emission and reflection, and a stable spherical standing wave focusing sound field and a sub-wavelength fine focal area can be realized, so that the ultrasonic transducer can obtain 10 9 Pa high sound pressure, thereby providing a new research platform for scientific research. In this embodiment, the ultrasonic transmitting unit is located on the inner surface of the shell, and the ultrasonic transmitting unit can transmit ultrasonic waves and make the ultrasonic waves propagate directly in the medium. Since the shell is rigid and its thickness is dozens of times the wavelength of the ultrasonic wave, the transmission efficiency of the ultrasonic transducer is relatively high.

[0038] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An ultrasonic transducer, characterized in that: The invention comprises: a shell, a cavity is arranged inside the shell, at least one ultrasonic transmitting unit for transmitting ultrasonic waves is arranged on the inner surface of the shell, the ultrasonic transmitting unit has the function of reflecting ultrasonic waves, and the cavity is a resonance cavity; The ultrasonic wave emitted by the ultrasonic transmitting unit and the reflected wave formed by the ultrasonic wave reflected by the ultrasonic transmitting unit are focused on the focal area of ​​the ultrasonic transmitting unit; There are multiple ultrasonic transmitting units, each of which is a piezoelectric array element; the multiple piezoelectric array elements are arranged on the surface of the cavity in an equidistant manner; The shape of the cavity is a truncated spherical shell including the center of the sphere, and the focal area of ​​the ultrasonic transmitting unit is the position of the center of the sphere of the cavity; The ultrasonic transducer further comprises: an upper end cover and a lower end cover, wherein the upper end cover is located above the cavity and is mounted on the shell; the lower end cover is located below the cavity and is mounted on the shell; The ultrasonic transducer also includes: a connecting seat and a power aviation plug, the connecting seat is a pressure-resistant connecting seat, and the power aviation plug is a pressure-resistant power aviation plug connector. The connecting seat and the power aviation plug connector both adopt watertight joints and integrated vulcanized cables. Double sealing is adopted for the mounting surfaces of the connecting seat and the power aviation plug connector to ensure that the hydrostatic pressure withstood by the ultrasonic transducer is greater than or equal to 10MPa.

2. The ultrasonic transducer according to claim 1, characterized in that: The material of the shell is aluminum alloy or steel.

3. The ultrasonic transducer according to claim 1, characterized in that: An electrode protection layer is arranged on the inner surface of the ultrasonic transmitting unit.

4. The ultrasonic transducer according to claim 1, characterized in that: A matching layer is arranged on the inner surface of the ultrasonic transmitting unit.

5. The ultrasonic transducer according to claim 1, characterized in that: The operating frequency of the ultrasonic transmitting unit is 400kHz to 1200kHz.

6. The ultrasonic transducer according to claim 1, characterized in that: The thickness of the shell is 20 mm to 50 mm.

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