Self-focusing medical ultrasonic diagnostic array transducer

Abstract

The application relates to the technical field of ultrasonic transducers, in particular to a self-focusing medical ultrasonic diagnostic array transducer, which comprises, from bottom to top, a backing layer, a piezoelectric layer, a matching layer and an outer layer, the piezoelectric layer is connected with the backing layer and the matching layer in a precise gluing mode, a plurality of array elements are formed by longitudinally slicing and dividing the piezoelectric layer and the matching layer into small squares, the backing layer is composed of a plurality of layers of composite materials with different acoustic impedance rates arranged linearly in the longitudinal direction, the piezoelectric layer is composed of piezoelectric composite materials arranged linearly in the longitudinal direction, and the matching layer is composed of composite materials with different acoustic impedance rates arranged linearly in the longitudinal direction. The core of the application is to control the parameters of the matching layer and the backing material, so that the longitudinal sensitivity is distributed in a certain way, the longitudinal self-focusing is realized, the longitudinal beam characteristics of the transducer are improved, the method is simple, and the manufacturing cost is not high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic transducer, in particular to a self-focusing medical ultrasonic diagnostic array transducer. BACKGROUND

[0002] Electronic scanning ultrasonic diagnostic instrument is essentially a medical device that transmits ultrasonic beams into the human body in a certain scanning section and receives the ultrasonic waves reflected by the human body to process and display images. The size of the section has a great influence on the image quality. The application requires uniform and narrow sections, but in fact, the sections are not uniform. The array scanning direction generally adopts electronic focusing method, uses a multi-channel pulse circuit, and is equipped with a multi-element high-density probe to generate very small transmission ultrasonic beams along the arrangement direction of the transducer array to complete the scanning in a certain way. The electronic scanning direction is referred to as the transverse scanning direction here. The longitudinal direction of the transducer array, i.e. perpendicular to the transverse scanning direction, generally adopts the height of the wafer and focusing components to implement the focusing, and other methods such as the shape of the transducer element, such as concave surface, are also used to implement the focusing. The longitudinal focusing effect is defined by the section thickness in the product standard of the ultrasonic diagnostic instrument. Generally, the section thickness is different at different detection distances, narrow at the acoustic focal point, and wide away from the focal point. The ideal longitudinal focusing should be appropriately narrow and uniform, i.e. have a long focal depth. Especially in the application of 3D probes, this influence will be great. Recently, electronic focusing methods have also been used to control and electronically focus in the height direction. However, this method is very complex in control and the transducer manufacturing process is complicated, and the cost is too high. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application discloses a self-focusing medical ultrasonic diagnostic array transducer. The longitudinal focusing is achieved by using different backings and matching materials to make the longitudinal vibration velocity of the transducer distribute in a certain shape. According to the vibration principle, the synthesized beam characteristics are related to the displacement amplitude distribution, and appropriate displacement distribution can improve the longitudinal focusing effect. Combined with other focusing methods, long-distance longitudinal focusing is achieved. Data calculation shows that the focusing level is greatly improved. By using this vibration velocity control method, the required beam characteristics can be achieved. If the longitudinal vibration velocity is distributed in a Gaussian distribution, the requirement of constant section thickness in the entire acoustic field can be met.

[0004] The present application is implemented by the following technical solutions:

[0005] A self-focusing medical ultrasonic diagnostic array transducer comprises a backing layer, a piezoelectric layer, a matching layer and an outer layer which are sequentially distributed from bottom to top, the piezoelectric layer is connected with the backing layer and the matching layer by precise gluing, and the piezoelectric layer and the matching layer are divided into small squares by longitudinal slicing to form a plurality of elements.

[0006] The backing layer is composed of longitudinally linearly arranged multiple layers of variable backing composite material; the piezoelectric layer is composed of longitudinally linearly arranged multiple layers of piezoelectric composite material; and the matching layer is composed of longitudinally linearly arranged multiple layers of variable matching composite material.

[0007] Preferably, the piezoelectric layer adopts 2-2 or 1-3 type piezoelectric composite material, the matching layer adopts 2-2 type matching composite material, and the backing layer adopts 2-2 type backing composite material.

[0008] Preferably, the height of the piezoelectric layer is generally above 4 mm.

[0009] Preferably, the main material of the matching layer composite material adopts epoxy material, and is doped with mixed nano particles of different high densities.

[0010] Preferably, the composite material preparation method of the matching layer is as follows: low-viscosity epoxy material is mixed with high-density nano material, and is stirred uniformly by a stirrer and cured at medium temperature; within a certain mixing ratio, the longitudinal wave speed of the composite material is basically unchanged, but the density is variable, and the composite material density increases with the increase of the proportion of nano material.

[0011] Preferably, the processing method of the matching layer is as follows:

[0012] The material prepared according to the composite material preparation method of the matching layer is processed into a sheet and is ground; the thickness size is the same as the piezoelectric size in the 2-2 type piezoelectric composite material; a series of sheet materials with different densities and similar speeds are manufactured by this method;

[0013] The material is glued, the gluing size is controlled to be the same as the polymer width in the 2-2 type piezoelectric composite material, and is ground according to the 1 / 4 matching layer thickness; the composite matching layer is formed after the grinding is completed, and the acoustic impedance rate is formed according to the matching layer arranged in a certain way.

[0014] The present application has the following beneficial effects:

[0015] For medical ultrasonic array transducer, the lateral scanning direction uses multi-array element electronic control beam forming method to realize very narrow ultrasonic beam, and the quality level of human tissue detection is improved through variable aperture and full range dynamic focusing method. However, the longitudinal focusing is different, even if the whole transmitting system including the probe has great bandwidth, covering the application of human tissue cells, but the conventional probe size is fixed, and the slice thickness of the system cannot be guaranteed to be uniform and small. If longitudinal electronic control is used, it is very complex and expensive, similar to the surface array element control method, so it is difficult to realize long distance longitudinal focusing by using the traditional method. By using the method of the application, the core is to control the parameters of the matching layer and the backing material to achieve a certain distribution of longitudinal sensitivity or transducer displacement, realize longitudinal self-focusing, the method is simple, the manufacturing cost is not large, combined with the conventional focusing method, the slice thickness is effectively controlled, and the longitudinal focusing depth length is greatly improved. The ultrasonic array transducer can be applied to conventional piezoelectric and composite materials, and its effect is self-evident. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Fig. 1 The structure diagram of the array transducer of the embodiment of the present application.

[0018] Fig. 2 The schematic diagram of the core component of the array transducer of the embodiment of the present application.

[0019] Fig. 3 The mold module image of the ultrasonic diagnostic instrument without focusing piece (the lateral electronic focusing of the high-frequency probe is unchanged, and other settings are unchanged) in the embodiment of the present application.

[0020] Fig. 4 The mold module image of the ultrasonic diagnostic instrument with focusing piece (the lateral electronic focusing of the same high-frequency probe is the same as above, and other settings are the same) in the embodiment of the present application. Fig. 3 and Fig. 4 In the above, it is proved that the slice thickness has an effect on the image of the ultrasonic probe.

[0021] In the figure: 100: backing layer; 200: piezoelectric layer; 300: matching layer; 400: outer layer; 500: 2-2 type backing composite material; 600: 2-2 type piezoelectric composite material; 700: 2-2 type matching composite material. DETAILED DESCRIPTION

[0022] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] Referring to Figs. 1-4 The present application provides a self-focusing medical ultrasonic diagnostic array transducer, comprising a backing layer 100, a piezoelectric layer 200, a matching layer 300 and an outer layer 400 arranged in sequence from bottom to top, the piezoelectric layer 200 is connected with the backing layer 100 and the matching layer 300 by precise gluing, and a plurality of array elements are formed by longitudinally slicing and dividing the piezoelectric layer 200 and the matching layer 300 into small squares.

[0024] The backing layer 100 is composed of a plurality of layers of variable backing composite materials arranged linearly in the longitudinal direction; the piezoelectric layer 200 is composed of a plurality of layers of piezoelectric composite materials arranged linearly in the longitudinal direction; and the matching layer 300 is composed of a plurality of layers of variable matching composite materials arranged linearly in the longitudinal direction.

[0025] The piezoelectric layer 200 adopts 2-2 or 1-3 type piezoelectric composite materials, the matching layer 300 adopts 2-2 type matching composite materials 700, and the backing layer 100 adopts 2-2 type backing composite materials 500.

[0026] The height of the piezoelectric layer 200 is generally more than 4 mm.

[0027] The main material of the composite material of the matching layer 300 adopts epoxy material, and is also doped with mixed nano particles of different high densities.

[0028] In the embodiments of the present application, the preparation method of the composite material of the matching layer 300 is as follows: the low-viscosity epoxy material is mixed with high-density nano material, stirred uniformly by a stirrer, and cured at medium temperature; within a certain mixing ratio, the sound velocity of the composite material is basically unchanged, but the density is variable, and the density of the composite material increases with the increase of the proportion of nano material.

[0029] The processing method of the matching layer 300 is as follows:

[0030] The material prepared according to the preparation method of the composite material of the matching layer 300 is processed into a sheet and ground; the thickness size is the same as the piezoelectric size in the 2-2 type piezoelectric composite material 600; a series of sheet materials with different densities and similar sound velocities are made by this method;

[0031] The material is glued, the gluing size is controlled to be the same as the polymer width in the 2-2 type piezoelectric composite material 600, longitudinal grinding is performed according to the thickness of the 1 / 4 matching layer 300, and the composite matching layer 300 is formed after grinding, and the acoustic impedance rate is formed according to the variable matching layer 300 in a certain arrangement.

[0032] According to the design requirement, the acoustic impedance rates on both sides of the sheet are close to the optimal matching value, the density gradually decreases to the middle, the acoustic impedance rate changes, and then the longitudinal displacement of the transducer element is realized to be concave distribution, the longitudinal self-focusing of the radiated ultrasonic is realized; if the longitudinal displacement amplitude is realized according to the Gaussian distribution, the acoustic focusing beam remains unchanged during the propagation process, and the sheet thickness is uniform and unchanged.

[0033] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A self-focusing medical ultrasound diagnostic array transducer, characterized in that, It includes a backing layer, a piezoelectric layer, a matching layer and an outer layer arranged from bottom to top. The piezoelectric layer is connected to the backing layer and the matching layer by a precise adhesive bonding method. The piezoelectric layer and the matching layer are longitudinally divided into small squares to form several array elements. The backing layer is composed of composite materials with different acoustic impedances arranged linearly in the longitudinal direction; the piezoelectric layer is composed of piezoelectric composite materials arranged linearly in the longitudinal direction; the matching layer is composed of composite materials with different acoustic impedances arranged linearly in the longitudinal direction. The main material of the matching layer composite material is epoxy material, which is also doped with mixed nanoparticles of different densities. The method for preparing the composite material of the matching layer is as follows: Low-viscosity epoxy material is mixed with high-density nanomaterials, stirred evenly with a stirrer, and cured at medium temperature. Within a certain mixing ratio, the longitudinal wave velocity of this composite material remains basically unchanged, but the density changes. The density of the composite material increases with the increase of the proportion of nanomaterials, and its acoustic impedance also increases with the increase of the proportion of nanomaterials.

2. The self-focusing medical ultrasound diagnostic array transducer according to claim 1, characterized in that, The piezoelectric layer is made of 2-2 or 1-3 type piezoelectric composite material, the matching layer is made of 2-2 type matching composite material, and the backing layer is made of 2-2 type backing composite material.

3. The self-focusing medical ultrasound diagnostic array transducer according to claim 1, characterized in that, The height of the piezoelectric layer is 4 mm or more.

4. A self-focusing medical ultrasound diagnostic array transducer according to claim 1, characterized in that, The processing method for the matching layer is as follows: The material prepared according to the composite material preparation method of the matching layer is processed into thin sheets and ground; its thickness is the same as that of the piezoelectric dimension in the 2-2 type piezoelectric composite material; a series of thin sheet materials with different densities and similar sound velocities are made using this method; These materials are glued together, and the glued dimensions are controlled to be the same as the polymer width in the 2-2 type piezoelectric composite material. The material is then longitudinally ground to a thickness of 1 / 4 of the matching layer. Once the grinding is complete, a composite matching layer is formed, and its acoustic impedance is formed by a matching layer with a certain arrangement.

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