Multi-layer high-performance ultrasonic transducer matching layer structure and preparation method thereof

Abstract

The invention belongs to the technical field of ultrasonic transducers, and particularly relates to a multi-layer high-performance ultrasonic transducer matching layer structure and a preparation method thereof. The matching layer structure at least comprises five slurry layers with different acoustic impedances, and every two adjacent slurry layers are firmly combined through interface crosslinking; the formula of each slurry layer consists of the following components in parts by weight: 100 parts of a polymer matrix; the polymer matrix is one of polyurethane, epoxy resin and polyimide; 40 to 600 parts of an acoustic filler; the acoustic filler is one or a combination of more of metal powder, hollow glass microspheres and polymer hollow microspheres; 5 to 30 parts of a cross-linking agent; the cross-linking agent is a silane cross-linking agent. Continuous gradual change of acoustic impedance is achieved, the size is smaller, and the performance is more uniform and controllable.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic transducer technology, and specifically relates to a multi-layered high-performance ultrasonic transducer matching layer structure and its preparation method. Background Technology

[0002] Ultrasonic transducers are key components in modern medical imaging, industrial inspection, and other fields, and their performance directly affects imaging quality and detection accuracy. The matching layer, as a crucial component of the transducer, primarily functions to achieve acoustic impedance matching between the piezoelectric material and the object being inspected, thereby improving acoustic energy transmission efficiency.

[0003] Currently, traditional matching layer materials mainly face the following technical problems:

[0004] 1. Insufficient acoustic performance: Single materials struggle to achieve gradual changes in acoustic impedance over a wide frequency range, leading to severe sound wave reflection at interfaces and limited bandwidth. 2. Limited mechanical properties: Traditional polymers, metals, and ceramics often lack the simultaneous high strength, high toughness, and excellent fatigue resistance, hindering the transducer's sensitivity response and long-term stability. 3. Limited structural design: Existing matching layer materials are mostly simple single-layer or double-layer structures, unable to achieve continuous gradual changes in acoustic impedance, thus limiting performance improvements. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-layer high-performance ultrasonic transducer matching layer structure and its preparation method. This invention adopts a structure of at least five layers to achieve a continuous and gradual change in acoustic impedance, resulting in smaller size and more uniform and controllable performance.

[0006] To solve the above technical problems, the present invention provides a multi-layer high-performance ultrasonic transducer matching layer structure, wherein the matching layer structure comprises at least five slurry layers with different acoustic impedances, and adjacent slurry layers are firmly bonded together through interfacial cross-linking.

[0007] Each of the slurry layers is composed of the following components in parts by weight:

[0008] Polymer matrix: 100 parts; the polymer matrix is ​​one of polyurethane, epoxy resin and polyimide;

[0009] Acoustic filler: 40-600 parts; the acoustic filler is one or a combination of several of the following: metal powder, hollow glass microspheres, and polymer hollow microspheres;

[0010] Crosslinking agent: 5-30 parts; the crosslinking agent is a silane crosslinking agent.

[0011] Preferably, the five layers of slurry with different acoustic impedances include: a high-impedance slurry layer, a relatively high-impedance slurry layer, a medium-impedance slurry layer, a relatively low-impedance slurry layer, and a low-impedance slurry layer; to form an acoustic impedance gradient distribution in the range of 5 MRayl to 25 MRayl.

[0012] Preferably, the high-resistivity slurry layer is formulated with the following components in parts by weight: epoxy resin: 100 parts; metal powder: 600 parts; crosslinking agent: 30 parts.

[0013] Preferably, the formulation of the higher resistance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; metal powder: 60 parts; crosslinking agent: 20 parts.

[0014] Preferably, the formulation of the intermediate resistance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 40 parts; polymer hollow microspheres: 10 parts; crosslinking agent: 10 parts.

[0015] Preferably, the formulation of the lower impedance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 30 parts; polymer hollow microspheres: 15 parts; crosslinking agent: 8 parts.

[0016] Preferably, the low-resistivity slurry layer is formulated with the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 20 parts; polymer hollow microspheres: 20 parts; crosslinking agent: 5 parts.

[0017] This invention also provides a method for fabricating a multilayer high-performance ultrasonic transducer matching layer structure, to prepare a multilayer high-performance ultrasonic transducer matching layer structure as described above, comprising:

[0018] Step S1: Slurry preparation; The polymer matrix, acoustic filler and crosslinking agent are mixed according to the formula, and a uniform slurry is prepared by stirring and ultrasonic dispersion.

[0019] Step S2: Alternating spin coating; Using an alternating spin coating technique, different acoustic impedance pastes are sequentially coated on the substrate to form paste layers. By controlling the paste layer ratio and spin coating parameters, the thickness of each layer is precisely controlled.

[0020] Step S3: Interfacial crosslinking treatment; after each coating layer is applied, preheat and cure at 85°C for 10 min to achieve interlayer crosslinking;

[0021] Step S4: Hot pressing and curing; The multilayer structure is hot-pressed and cured at 120°C and 3MPa pressure to form a dense multilayer structure;

[0022] Step S5: Post-processing; according to the transducer size requirements, perform cutting and polishing post-processing procedures.

[0023] Preferably, each of the slurry layers has the same thickness, which is 0.2 mm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Excellent acoustic performance: Through multi-layer structure and gradient acoustic impedance design, the transmittance of sound waves reaches 60-80%, and the bandwidth of the ultrasonic transducer reaches 80-120%.

[0026] 2. Innovative structural design, employing at least five layers to achieve continuous and gradual change in acoustic impedance, resulting in smaller size and more uniform and controllable performance.

[0027] 3. The advanced preparation process achieves precise control and firm bonding of the multi-layer structure through alternating spin coating and interfacial cross-linking treatment, making it suitable for mass production. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a multi-layered high-performance ultrasonic transducer matching layer structure provided by the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0030] like Figure 1 As shown, this embodiment of the invention provides a multi-layer high-performance ultrasonic transducer matching layer structure, wherein the matching layer structure comprises at least five slurry layers with different acoustic impedances, and adjacent slurry layers are firmly bonded together through interfacial cross-linking.

[0031] Each of the slurry layers is composed of the following components in parts by weight:

[0032] Polymer matrix: 100 parts; the polymer matrix is ​​one of polyurethane, epoxy resin and polyimide;

[0033] Acoustic filler: 40-600 parts; the acoustic filler is one or a combination of several of the following: metal powder, hollow glass microspheres, and polymer hollow microspheres;

[0034] Crosslinking agent: 5-30 parts; the crosslinking agent is a silane crosslinking agent.

[0035] Preferably, the five layers of slurry with different acoustic impedances include: a high-impedance slurry layer, a relatively high-impedance slurry layer, a medium-impedance slurry layer, a relatively low-impedance slurry layer, and a low-impedance slurry layer; to form an acoustic impedance gradient distribution in the range of 5 MRayl to 25 MRayl.

[0036] Preferably, the high-resistivity slurry layer is formulated with the following components in parts by weight: epoxy resin: 100 parts; metal powder: 600 parts; crosslinking agent: 30 parts.

[0037] Preferably, the formulation of the higher resistance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; metal powder: 60 parts; crosslinking agent: 20 parts.

[0038] Preferably, the formulation of the intermediate resistance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 40 parts; polymer hollow microspheres: 10 parts; crosslinking agent: 10 parts.

[0039] Preferably, the formulation of the lower impedance slurry layer consists of the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 30 parts; polymer hollow microspheres: 15 parts; crosslinking agent: 8 parts.

[0040] Preferably, the low-resistivity slurry layer is formulated with the following components in parts by weight: epoxy resin: 100 parts; hollow glass microspheres: 20 parts; polymer hollow microspheres: 20 parts; crosslinking agent: 5 parts.

[0041] This invention also provides a method for fabricating a multilayer high-performance ultrasonic transducer matching layer structure, to prepare a multilayer high-performance ultrasonic transducer matching layer structure as described above, comprising:

[0042] Step S1: Slurry preparation; The polymer matrix, acoustic filler and crosslinking agent are mixed according to the formula, and a uniform slurry is prepared by stirring and ultrasonic dispersion.

[0043] Step S2: Alternating spin coating; Using an alternating spin coating technique, different acoustic impedance pastes are sequentially coated on the substrate to form paste layers. By controlling the paste layer ratio and spin coating parameters, the thickness of each layer is precisely controlled.

[0044] Step S3: Interfacial crosslinking treatment; after each coating layer is applied, preheat and cure at 85°C for 10 min to achieve interlayer crosslinking;

[0045] Step S4: Hot pressing and curing; The multilayer structure is hot-pressed and cured at 120°C and 3MPa pressure to form a dense multilayer structure;

[0046] Step S5: Post-processing; according to the transducer size requirements, perform cutting and polishing post-processing procedures.

[0047] Preferably, each of the slurry layers has the same thickness, which is 0.2 mm.

[0048] Furthermore, the acoustic impedance of the multilayer matching layer is gradient-distributed in the range of 5-25 MNayl, gradually transitioning from high to low values ​​from the side closer to the piezoelectric material to the side farther away, thus achieving good matching with the object being tested.

[0049] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A multi-layer high performance ultrasonic transducer matching layer structure, characterized by, The matching layer structure comprises at least five layers of slurry layers with different acoustic impedance, and the adjacent two layers of slurry layers are firmly combined through interface cross-linking; The formula of each layer of the slurry layer is composed of the following components by weight: Polymer matrix: 100 parts; the polymer matrix is one of polyurethane, epoxy resin and polyimide; Acoustic filler: 40-600 parts; the acoustic filler is one or a combination of several of metal powder, hollow glass microspheres and high polymer hollow microspheres; Cross-linking agent: 5-30 parts; the cross-linking agent is a silane cross-linking agent.

2. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 1, wherein, The five layers of slurry layers with different acoustic impedance include: a high-impedance slurry layer, a higher-impedance slurry layer, a medium-impedance slurry layer, a lower-impedance slurry layer and a low-impedance slurry layer; to form a gradient distribution of acoustic impedance in the range of 5MRayl-25MRayl.

3. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 2, wherein, The formula of the high-impedance slurry layer is composed of the following components by weight: epoxy resin: 100 parts; metal powder: 600 parts; cross-linking agent: 30 parts.

4. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 2, wherein, The formula of the higher-impedance slurry layer is composed of the following components by weight: epoxy resin: 100 parts; metal powder: 60 parts; cross-linking agent: 20 parts.

5. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 2, wherein, The formula of the medium-impedance slurry layer is composed of the following components by weight: epoxy resin: 100 parts; hollow glass microspheres: 40 parts; high polymer hollow microspheres: 10 parts; cross-linking agent: 10 parts. The formula of the lower-impedance slurry layer is composed of the following components by weight: epoxy resin: 100 parts; hollow glass microspheres: 30 parts; high polymer hollow microspheres: 15 parts; cross-linking agent: 8 parts. The formula of the low-impedance slurry layer is composed of the following components by weight: epoxy resin: 100 parts; hollow glass microspheres: 20 parts; high polymer hollow microspheres: 20 parts; cross-linking agent: 5 parts.

6. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 2, wherein, It includes: Step S1: slurry preparation; the polymer matrix, acoustic filler and cross-linking agent are mixed according to the proportion, and uniform slurry is prepared through stirring and ultrasonic dispersion treatment; Step S2: alternating spin coating; different acoustic impedance slurry is coated on the substrate in sequence by using layer-by-layer alternating spin coating technology to form a slurry layer, and the thickness of each layer is accurately controlled by controlling the proportion of the slurry layer and the spin coating parameters; 7. A multi-layer high performance ultrasonic transducer matching layer structure as defined in claim 2, wherein, Step S3: interface cross-linking treatment; After each layer is coated, preheat and solidify at 85°C for 10 minutes to realize interlayer cross-linking; Step S4: hot pressing and curing; the multilayer structure is hot pressed and cured at 120°C and 3MPa pressure to form a dense multilayer structure; 8. A method of manufacturing a multilayer high-performance ultrasonic transducer matching layer structure according to any one of claims 1 to 7, characterized in that Step S5: post-processing; according to the size requirements of the transducer, cutting and polishing post-processing procedures are carried out. The thickness of each layer of the slurry layer is the same, which is 0.2mm. ​ ​ ​ ​ ​ 9. A method of fabricating a multilayer high performance ultrasonic transducer matching layer structure as claimed in claim 8, wherein, ​

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