Anti-reflection ultrasonic coupling material with gradually changed acoustic impedance

Abstract

The invention discloses an acoustic impedance gradient anti-reflection ultrasonic coupling material, which realizes acoustic impedance gradient by introducing an oppositely complementary inclined split structure with parallel bottom edges. The structure comprises two oblique wedge structures with different acoustic impedances, and the acoustic impedances at different positions in the sound wave propagation direction can be equivalent to the average value of the acoustic impedances of the two oblique wedges. Acoustic impedance continuous change between the piezoelectric material and the measured object is realized through the device, that is, ultrasonic waves can be propagated between the piezoelectric material and the measured object more smoothly, reflection of the ultrasonic waves is remarkably reduced, more energy enters human tissues, meanwhile, echo signals are stronger, developed images are clearer, and the measurement accuracy is improved. Therefore, the ultrasonic transmission capability and the ultrasonic detection precision and efficiency are improved, and the method has wide technical application potential.

Description

Technical Field

[0001] The present invention relates to the field of new medical ultrasonic materials, and in particular to an anti-transmission ultrasonic coupling material with a gradual change in acoustic impedance, which is used to enhance the transmission ability of ultrasonic waves and improve the effects of ultrasonic detection and treatment. Background Art

[0002] Ultrasound is of great significance in clinical disease diagnosis, auxiliary treatment and detection of treatment effects.

[0003] When ultrasound waves propagate in different media, they will be reflected and refracted at the interface due to differences in acoustic impedance, resulting in energy loss of the ultrasonic signal and reducing the performance and clinical effect of the ultrasonic equipment. To solve the above problems, acoustic impedance matching materials are filled between the ultrasonic transducer and the object being measured or treated. This material can provide acoustic impedance matching effects and achieve a gradual transition of acoustic impedance, which is of great significance to improving the effect and application scope of ultrasonic technology. It is widely used in disease diagnosis, non-invasive ultrasonic treatment, and ultrasonic non-destructive testing.

[0004] The general acoustic impedance matching material has an acoustic impedance between the acoustic impedance of the piezoelectric material of the ultrasonic transducer and the acoustic impedance of the object to be measured, and is bonded to the front end of the ultrasonic transducer to promote the ultrasonic transducer to propagate ultrasonic waves into the object to be measured. However, when the acoustic impedance of the piezoelectric material of the ultrasonic transducer is quite different from the acoustic impedance of the object to be measured, the single-layer acoustic impedance matching material is often not effective enough, and a double-layer or even multi-layer acoustic impedance matching material is required. For example, the Chinese invention patent "Matching layer of ultrasonic transducer stack, ultrasonic transducer stack and method for producing matching layer of ultrasonic transducer stack" (publication number CN 103861796A) proposes a structure and processing method of a multi-layer matching material. However, this multi-layer matching material has shortcomings, that is, this matching material is formed by bonding multiple different matching layers by adhesives, and the acoustic impedance of the adhesive is inconsistent with the acoustic impedance of the matching material, that is, the presence of the adhesive makes the acoustic impedance between the bonding layer and the matching material layer discontinuous, which in turn limits the ultrasonic transmission effect of this multi-layer matching material to a certain extent, especially when the ultrasonic frequency is high and the wavelength is short. The negative impact is greater. In addition, if this multi-layer matching processing method is to achieve the effect of gradual change of acoustic impedance, the matching layer needs to be divided into a large number of stacked layers, which increases the processing complexity and reduces the yield rate. Summary of the invention

[0005] One of the purposes of the present invention is to provide an anti-transmittance ultrasonic coupling material with a gradient acoustic impedance in order to solve the above-mentioned technical problems, so as to achieve the gradient acoustic impedance without introducing additional adhesives. This ultrasonic matching material structure with a gradient acoustic impedance adopts two bevel structures with parallel bottom edges and opposed complementary to each other, including a first bevel structure and a second bevel structure. When sound waves propagate in this anti-transmittance ultrasonic coupling material, the acoustic impedances at different positions in the direction of sound wave propagation can be equivalent to the average value of the acoustic impedances of the two bevel structures. In the direction of sound wave propagation, since the proportions of the two bevel structures change continuously, the acoustic impedance of the anti-transmittance ultrasonic coupling material is also gradient. The acoustic impedances of the two bevel structures can be adjusted by changing the type and proportion of the internal particulate admixtures, so as to adapt to different piezoelectric materials and objects under test;

[0006] In order to achieve the above patent purpose, the technical solution adopted by the present invention is as follows: 1. Slant split structure design: As attached Figure 1 As shown, an anti-transmittance ultrasonic coupling material with a gradual acoustic impedance change is placed on the piezoelectric material of the ultrasonic transducer, and the anti-transmittance ultrasonic coupling material is tightly fitted with the object to be measured, and can form an acoustic impedance transition between the piezoelectric material and the object to be measured; the anti-transmittance ultrasonic coupling material with a gradual acoustic impedance change is divided into a first oblique split structure and a second oblique split structure, and the two oblique split structures are arranged in a manner of parallel bottom edges and opposite to each other and are formed by mixing and solidifying the same homogeneous base material and particles mixed therein, wherein the first oblique split structure and the second oblique split structure each contain a particle, and the types of the particles contained are different; An anti-transmission ultrasonic coupling material with a gradient acoustic impedance, comprising two oblique wedge structures with different acoustic impedances, namely a first oblique wedge structure and a second oblique wedge structure, wherein the two oblique wedge structures are arranged in a manner that the bottom edges are parallel and opposed to each other and complement each other; the first oblique wedge structure and the second oblique wedge structure are formed by mixing and solidifying the same homogeneous base material and particles mixed therein, wherein the first oblique wedge structure and the second oblique wedge structure each contain a particle, and the types of the particles contained are different; To better implement the present invention, further, the bottom width W of the oblique wedge structure is less than 1 / 4 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the base material; To better implement the present invention, further, the radius λ of the particle is less than 1 / 40 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the substrate material; To better implement the present invention, further, the thickness H of the acoustic impedance gradient anti-transmission ultrasonic coupling material is an odd multiple of 1 / 4 of the arithmetic mean of the wavelengths of the sound waves corresponding to the center frequency of the ultrasonic transducer in the piezoelectric material and the object under test respectively; To better implement the present invention, further, the acoustic impedances of the first wedge structure and the second wedge structure are Z1 and Z2 respectively, and the equivalent acoustic impedances at different positions in the direction of sound wave propagation are weightedly calculated according to the proportions of the two wedge materials and the specific values ​​of Z1 and Z2; To better implement the present invention, further, the substrate material is one of epoxy resin or PDMS material; 2. Acoustic impedance gradient realization: The acoustic impedances of the first wedge structure and the second wedge structure are Z1 and Z2 respectively. By changing the type and proportion of the internal particulate matter of the wedge material, the equivalent acoustic impedance of the two wedge structures after synthesis is adjusted to adapt to different piezoelectric materials and objects under test. To better implement the present invention, further, the acoustic impedance Z1 of the first wedge structure depends on the equivalent acoustic impedance of a base material with an acoustic impedance Zb and an admixture 1 with an acoustic impedance Zd1, wherein the acoustic impedance Zd1 of the admixture 1 is greater than the acoustic impedance Zp of the piezoelectric material, and Zb+Zd1>Zp×2; To better implement the present invention, further, the acoustic impedance Z2 of the second wedge structure depends on the equivalent acoustic impedance of the base material with an acoustic impedance Zb and the admixture 2 with an acoustic impedance Zd2, wherein the acoustic impedance Zd2 of the admixture 2 is less than the acoustic impedance Zt of the target object, and Zb+Zd2 <Zt×2; To better implement the present invention, further, the particulate matter is an admixture 1 having an acoustic impedance greater than Zp and an admixture 2 having an acoustic impedance less than Zt; In order to better realize the present invention, further, the acoustic impedance of the admixture 1 and the admixture 2 needs to meet the technical requirements, and should be easy to process and easy to mix with the base material; To better implement the present invention, further, the admixture 1 is preferably tungsten powder, and the admixture 2 is preferably hollow glass microspheres; In order to better realize the present invention, further, the admixture 1 is added into the first oblique split structure, and the admixture 2 is added into the second oblique split structure; To better implement the present invention, further, the shape of the wedge structure is an isosceles triangle, and the bottom width W is less than 1 / 4 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the base material; To better implement the present invention, further, the ultrasonic transducer action device of the acoustic impedance gradient anti-transmission ultrasonic coupling material comprises: a piezoelectric material for emitting ultrasonic waves; To better implement the present invention, further, the anti-transmission ultrasonic coupling material with a gradual acoustic impedance is closely attached between the piezoelectric material of the ultrasonic transducer and the object to be measured, so as to realize a gradual transition of the acoustic impedance; To better implement the present invention, further, the ultrasonic transducer action device significantly improves the ultrasonic transmission ability and focusing accuracy through the acoustic impedance gradient anti-transmission ultrasonic coupling material; To better implement the present invention, further, the ultrasonic transducer action device is characterized in that: the ultrasonic transducer is a circular or array transducer, and the transmission frequency, power and pulse parameters are tuned by an external control system; To better implement the present invention, further, the transcranial ultrasound treatment device of the acoustic impedance gradient anti-transmission ultrasound coupling material comprises: an ultrasonic transducer for emitting ultrasonic waves; To better implement the present invention, further, the acoustic impedance gradient anti-transmission ultrasonic coupling material is closely attached between the piezoelectric material of the ultrasonic transducer and the skull to enhance the transmission ability of ultrasonic waves; To better implement the present invention, further, the transcranial ultrasound treatment device significantly improves the efficiency and accuracy of transcranial ultrasound treatment through the acoustic impedance gradient anti-transmittance ultrasound coupling material; To better implement the present invention, further, the transcranial ultrasound treatment device is characterized in that: the operating frequency of the ultrasound transducer is 0.1 MHz-3 MHz, which is suitable for transcranial ultrasound nerve regulation and treatment; To better implement the present invention, further, the ultrasonic nondestructive testing device of the anti-transmission ultrasonic coupling material with gradual acoustic impedance includes: an ultrasonic transducer for emitting ultrasonic waves; To better implement the present invention, further, the acoustic impedance gradient anti-transmission ultrasonic coupling material is closely attached between the piezoelectric material of the ultrasonic transducer and the object to be measured, so as to enhance the transmission ability of ultrasonic waves; To better implement the present invention, further, the ultrasonic nondestructive testing device significantly improves the accuracy and efficiency of ultrasonic testing through the anti-transmittance ultrasonic coupling material with gradual acoustic impedance change.

[0007] The second object of the present invention is to provide a method for preparing an anti-transmission ultrasonic coupling material with a gradual change in acoustic impedance, and the method is carried out according to the following operating steps: (1) Calculate the acoustic impedance of the first wedge structure and the second wedge structure and the corresponding particle content ratio based on the acoustic impedance of the piezoelectric material and the acoustic impedance of the object to be tested; (2) mixing the base material and the granular material 1 to form a first oblique split structure preparation material, and bonding the first oblique split structure preparation material to the emitting surface of the piezoelectric material of the ultrasonic transducer through mold casting or prefabrication into a layered process to obtain a first oblique split structure quasi-structure; (3) performing laser etching layer by layer on the first oblique-wedge structure quasi-structure to obtain a first oblique-wedge structure; (4) The base material and the particle 2 are mixed to form a second oblique-wedge structure preparation material, and the second oblique-wedge structure preparation material is loaded into the gap of the first oblique-wedge structure through a mold casting process, and then solidified to form a complete acoustic impedance gradient anti-reflection ultrasonic coupling material.

[0008] The present invention can be used for transcranial detection, coronary stent drug release, coronary balloon drug release, etc.

[0009] Beneficial effects of the present invention: After using the anti-reflection ultrasonic coupling material with gradual acoustic impedance, continuous change of acoustic impedance is achieved between the piezoelectric material and the object under test, that is, ultrasonic waves can propagate more smoothly between the piezoelectric material and the object under test, significantly reducing the reflection of ultrasonic waves and allowing more energy to enter human tissue. At the same time, the echo signal is stronger and the image is clearer, thereby improving the ultrasonic transmission ability and the accuracy and efficiency of ultrasonic detection.

[0010] Taking transcranial focused ultrasound used for the treatment of brain diseases as an example, the energy loss of the transcranial sound field without the use of acoustic impedance gradient anti-transmission ultrasound coupling materials is relatively large, and the maximum sound pressure at the focus is only about 9 kPa. After using the acoustic impedance gradient anti-transmission ultrasound coupling materials, the maximum sound pressure at the focus of the transcranial sound field increases to about 60 kPa, and its energy is significantly greater than that of the transcranial sound field without the use of acoustic impedance gradient anti-transmission ultrasound coupling materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A three-dimensional schematic diagram of the anti-reflective ultrasound coupling material Figure 2 Schematic diagram of the cross-sectional structure and application of anti-reflective ultrasonic coupling material Figure 3 This is the result of transcranial acoustic field detection without using anti-reflective ultrasound coupling material Figure 4 The results of transcranial acoustic field detection after using anti-reflective ultrasound coupling material Figure 5 Processing flow chart for anti-reflective ultrasonic coupling materials Figure 6 Schematic diagram of laser etching layer by layer DETAILED DESCRIPTION

[0012] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments and comparative examples, but the present invention is not limited to these specific embodiments, which are intended to explain the present invention rather than to limit it.

[0013] The following are examples and comparative examples.

[0014] Example 1 The base material epoxy resin accounting for 34% and the particulate material admixture 1 tungsten powder accounting for 66% are mixed to obtain the first oblique split structure preparation material; the first oblique split structure preparation material is bonded to the emission surface of the piezoelectric material PZT-4 of the ultrasonic transducer through a mold casting process to obtain the first oblique split structure quasi-structure; Then, the first oblique-wedge structure quasi-structure is laser-etched layer by layer to obtain a first oblique-wedge structure; The base material epoxy resin accounting for 83% and the particulate admixture 2 hollow glass beads accounting for 17% are mixed to obtain the second oblique wedge structure preparation material; through the mold casting process, the second oblique wedge structure preparation material is loaded into the gap of the first oblique wedge structure, and then cured to form a complete acoustic impedance gradient anti-transmission ultrasonic coupling material.

[0015] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that the ultrasonic coupling material does not adopt a wedge structure, but a traditional multi-layer matching layer structure, and the layers are bonded together with glue.

[0016] The above Example 1 and Comparative Example 1 were tested for transcranial sound field pressure, and the results are shown in Table 1; the acoustic impedance of the first wedge structure, the second wedge structure, the piezoelectric material PZT-4 and the human tissue of Example 1 were tested respectively, and the results are shown in Table 2; the transcranial sound field pressure was tested using Example 1 of the present invention and the two cases where the present invention was not used, and the results are shown in the attached Figure 3 and attached Figure 4 .

[0017] Table 1 Transcranial sound field sound pressure test results of Example 1 and Comparative Example 1

[0018] Table 2 Acoustic impedance test results

[0019] From the results in Table 1 and Table 2, it can be seen that a kind of ultrasonic coupling material with a gradual change in acoustic impedance can make the sound waves propagate more smoothly from the piezoelectric material to the object under test, realize the effective transition of acoustic impedance, and significantly improve the transmission ability of ultrasonic waves. Among them, Comparative Example 1 does not adopt the oblique split structure, but adopts the traditional multi-layer matching layer structure. As a result, the sound pressure is relatively low and the sound waves are wasted more, indicating that the traditional multi-layer matching structure is not conducive to the transmission of sound waves. The reason is that this traditional structure is made of layers of flat matching layers bonded by glue, and the glue layer has a certain thickness. When the transducer frequency is very high (corresponding to a very short wavelength), the glue layer will cause the acoustic impedance to jump, making the acoustic impedance between the bonding layer and the matching material layer discontinuous, which is not conducive to the transmission of sound waves, especially when the ultrasonic frequency is high and the wavelength is short. The negative impact is greater.

[0020] From the attached Figure 3 and attached Figure 4 It can be seen that, taking transcranial focused ultrasound used for the treatment of brain diseases as an example, the energy loss of the transcranial sound field without the use of an anti-transmission ultrasound coupling material with a gradual change in acoustic impedance is relatively large, and the maximum sound pressure at the focus is only about 9 kPa. However, the maximum sound pressure at the focus of the transcranial sound field after the use of an anti-transmission ultrasound coupling material with a gradual change in acoustic impedance increases to about 60 kPa, and its energy is significantly greater than that of the transcranial sound field without the use of an anti-transmission ultrasound coupling material with a gradual change in acoustic impedance.

[0021] The above results show that the anti-transmission ultrasonic coupling material with gradual acoustic impedance designed in the present invention can achieve an effective transition of acoustic impedance to a certain extent, promote the propagation of sound waves and thus improve the transmission ability, accuracy and efficiency of ultrasonic waves.

[0022] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An anti-transmission ultrasonic coupling material with a gradual change in acoustic impedance, characterized in that: The invention comprises two oblique split structures with different acoustic impedances, namely a first oblique split structure and a second oblique split structure, wherein the two oblique split structures are arranged in a manner that the bottom sides are parallel and opposed to each other and complement each other; the first oblique split structure and the second oblique split structure are formed by mixing and solidifying the same homogeneous base material and particles mixed therein, wherein the first oblique split structure and the second oblique split structure each contain at least one particle, and the types of the particles contained are different; The bottom width W of the oblique split structure is less than 1 / 4 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the base material; the radius λ of the particle is less than 1 / 40 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the base material; the thickness H of the acoustic impedance gradient anti-reflection ultrasonic coupling material is an odd multiple of 1 / 4 of the arithmetic mean of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the piezoelectric material and the object under test respectively; the acoustic impedances of the first oblique split structure and the second oblique split structure are Z1 and Z2 respectively, and the equivalent acoustic impedances at different positions in the direction of sound wave propagation are weightedly calculated according to the proportions of the two oblique split materials and the specific values ​​of Z1 and Z2; The preparation method comprises the following steps: (1) Calculate the acoustic impedance of the first wedge structure and the second wedge structure and the corresponding particle content ratio based on the acoustic impedance of the piezoelectric material and the acoustic impedance of the object to be tested; (2) mixing the base material and the granular material 1 to form a first oblique split structure preparation material, and bonding the first oblique split structure preparation material to the emitting surface of the piezoelectric material of the ultrasonic transducer through mold casting or prefabrication into a layered process to obtain a first oblique split structure quasi-structure; (3) performing laser etching layer by layer on the first oblique-wedge structure quasi-structure to obtain a first oblique-wedge structure; (4) The base material and the particle 2 are mixed to form a second oblique-wedge structure preparation material, and the second oblique-wedge structure preparation material is loaded into the gap of the first oblique-wedge structure through a mold casting process, and then solidified to form a complete acoustic impedance gradient anti-reflection ultrasonic coupling material.

2. The anti-transmission ultrasonic coupling material with a gradient acoustic impedance according to claim 1, characterized in that: The acoustic impedance Z1 of the first wedge structure depends on the equivalent acoustic impedance of a mixture of a base material with an acoustic impedance Zb and an admixture 1 with an acoustic impedance Zd1, wherein the acoustic impedance Zd1 of the admixture 1 is greater than the acoustic impedance Zp of the piezoelectric material, and Zb+Zd1>Zp×2.

3. The anti-transmission ultrasonic coupling material with a gradient acoustic impedance according to claim 1, characterized in that: The acoustic impedance Z2 of the second wedge structure depends on the equivalent acoustic impedance of the base material with an acoustic impedance of Zb and the admixture 2 with an acoustic impedance of Zd2, wherein the acoustic impedance Zd2 of the admixture 2 is less than the acoustic impedance Zt of the target object, and Zb+Zd2 <Zt×2。 4. The anti-transmission ultrasonic coupling material with a gradient acoustic impedance according to claim 1, characterized in that: The substrate material is one of epoxy resin and PDMS material.

5. The anti-transmission ultrasonic coupling material with a gradient acoustic impedance according to claim 1, characterized in that: The particles are admixture 1 whose acoustic impedance is greater than Zp and admixture 2 whose acoustic impedance is less than Zt; admixture 1 belongs to the first oblique splitting structure, and admixture 2 belongs to the second oblique splitting structure.

6. The anti-transmission ultrasonic coupling material with a gradient acoustic impedance according to claim 1, characterized in that: The shape of the wedge structure is an isosceles triangle, and the bottom width W is less than 1 / 4 of the wavelength of the sound wave corresponding to the center frequency of the ultrasonic transducer in the base material.

7. An ultrasonic transducer action device based on the acoustic impedance gradient anti-transmission ultrasonic coupling material according to any one of claims 1 to 6, characterized in that: include: The piezoelectric material is used to emit ultrasonic waves; the anti-reflection ultrasonic coupling material with a gradual acoustic impedance is tightly fitted between the piezoelectric material of the ultrasonic transducer and the object to be measured, so as to achieve a gradual transition of the acoustic impedance; the ultrasonic transducer action device can significantly improve its ultrasonic transmission ability through the anti-reflection ultrasonic coupling material with a gradual acoustic impedance.

8. The ultrasonic transducer action device according to claim 7, characterized in that: The ultrasonic transducer is a strip-shaped monomer or strip-shaped array transducer, and the transmission frequency, power and pulse parameters are tuned by an external control system.

9. A method for preparing an anti-transmission ultrasonic coupling material with a gradient acoustic impedance as claimed in any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) Calculate the acoustic impedance of the first wedge structure and the second wedge structure and the corresponding particle content ratio based on the acoustic impedance of the piezoelectric material and the acoustic impedance of the object to be tested; (2) mixing the base material and the granular material 1 to form a first oblique split structure preparation material, and bonding the first oblique split structure preparation material to the emitting surface of the piezoelectric material of the ultrasonic transducer through mold casting or prefabrication into a layered process to obtain a first oblique split structure quasi-structure; (3) performing laser etching layer by layer on the first oblique-wedge structure quasi-structure to obtain a first oblique-wedge structure; (4) The base material and the particle 2 are mixed to form a second oblique-wedge structure preparation material, and the second oblique-wedge structure preparation material is loaded into the gap of the first oblique-wedge structure through a mold casting process, and then solidified to form a complete acoustic impedance gradient anti-reflection ultrasonic coupling material.

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