Ultrasonic transducer and preparation method thereof

Abstract

The invention discloses an ultrasonic transducer and a preparation method thereof. The ultrasonic transducer comprises a stacked functional layer and an ultrasonic focus matching layer. Wherein the stacked functional layer comprises a conductive backing and a piezoelectric layer which are arranged in a stacked manner; the ultrasonic focusing matching layer is located on the side, away from the conductive backing, of the piezoelectric layer. A stepped groove is formed in the surface of one side, deviating from the piezoelectric layer, of the ultrasonic focusing matching layer; the stepped groove comprises a plurality of stepped structures. By adopting the technical scheme, the problems of complex preparation process and poor focusing capability of the focusing layer in the prior art can be solved, so that the effects of simplifying the preparation process and improving the production efficiency and yield are achieved on the premise of ensuring that the ultrasonic transducer has a good focusing effect.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of ultrasonic transducers, and in particular to an ultrasonic transducer and a method for preparing the same. Background Art

[0002] The ultrasonic transducer is the most advanced component in the entire ultrasonic system. The ultrasonic transducer can convert ultrasonic waves into electrical signals, and can also convert electrical signals into ultrasonic waves. Therefore, the ultrasonic transducer can realize signal detection, obstacle detection, ultrasonic imaging and directional treatment through ultrasonic waves.

[0003] The existing ultrasonic transducer has a large ultrasonic diffusion angle during the signal conversion process, which makes it impossible to accurately perform ultrasonic detection and imaging during detection, thereby reducing the sensitivity of the ultrasonic transducer. Summary of the invention

[0004] The present invention provides an ultrasonic transducer and a preparation method thereof to solve the defects existing in the prior art, so as to simplify the preparation process and the structure of the ultrasonic transducer while ensuring that the ultrasonic transducer has a good focusing effect, thereby effectively improving the production efficiency and the production yield.

[0005] In a first aspect, an embodiment of the present invention provides an ultrasonic transducer, comprising:

[0006] A stacked functional layer, the stacked functional layer comprising a conductive backing and a piezoelectric layer stacked in layers;

[0007] The ultrasonic focusing matching layer is located on the side of the piezoelectric layer away from the conductive backing; a stepped groove is arranged on the surface of the side of the ultrasonic focusing matching layer away from the piezoelectric layer; and the stepped groove includes a plurality of stepped structures.

[0008] Optionally, each step structure includes a step table and a step side surface that are connected and not coplanar; for the same step structure, the step table and the step side surface have a first common edge;

[0009] At least one point on the first common side of each stepped structure is located on the same arc.

[0010] Optionally, the ratio of the widths of the step terraces in two adjacent step structures is K;

[0011] Among them, 1≤K≤5.

[0012] Optionally, the step groove further includes a step groove bottom surface intersecting with the side surfaces of each step; the step groove bottom surface is tangent to the circular arc.

[0013] Optionally, the value range of the radius of curvature ROC of the arc is: 5 mm≤ROC≤25 mm.

[0014] Optionally, each step structure of the step groove is symmetrically distributed along the central axis of the ultrasonic focusing matching layer.

[0015] Optionally, the thickness of the bottom thickness T1 of the stepped groove has a value range of: λ / 8≤T1≤3λ / 4; λ is the wavelength of the ultrasonic wave.

[0016] Optionally, the ultrasonic transducer further includes: a first electrode lead and a second electrode lead disposed on opposite sides of the stacked functional layer, wherein the first electrode lead is connected to the ultrasonic focusing matching layer, and the second electrode lead is connected to the conductive backing.

[0017] Optionally, the minimum thickness T2 of the ultrasonic focusing matching layer satisfies: T2=C / F / 4*λ;

[0018] Wherein, C is the propagation velocity of the ultrasonic wave in the ultrasonic focusing matching layer, F is the operating frequency of the ultrasonic transducer, and λ is the wavelength of the ultrasonic wave.

[0019] Optionally, the material of the ultrasonic focusing matching layer includes polyparaxylene.

[0020] Optionally, the stacked functional layer further includes at least one impedance matching layer;

[0021] The impedance matching layer is located between the ultrasonic focusing matching layer and the piezoelectric layer.

[0022] In a second aspect, an embodiment of the present invention further provides a method for preparing an ultrasonic transducer, comprising:

[0023] forming a stacked functional layer; the stacked functional layer comprises a conductive backing and a piezoelectric layer stacked in layers;

[0024] An ultrasonic focusing matching layer is formed on the side of the piezoelectric layer away from the conductive backing; a stepped groove is arranged on the side of the ultrasonic focusing matching layer away from the piezoelectric layer; and the stepped groove includes a plurality of stepped structures.

[0025] Optionally, an ultrasonic focusing matching layer is formed on a side of the piezoelectric layer facing away from the conductive backing, comprising:

[0026] N stepped structures are formed in sequence on the side of the piezoelectric layer away from the conductive backing; wherein the i-th stepped structure surrounds the i+1-th stepped structure, and the height of the i-th stepped structure is greater than the height of the i+1-th stepped structure; each stepped structure constitutes an ultrasonic focusing matching layer; N is a positive integer greater than or equal to 2, and i is a positive integer less than N.

[0027] Optionally, N stepped structures are sequentially formed on a side of the piezoelectric layer facing away from the conductive backing, including:

[0028] forming an i-th focusing material layer having an i-th thickness on a side of the piezoelectric layer facing away from the conductive backing;

[0029] patterning the i-th focusing material layer to form an i-th opening and an i-th stepped structure surrounding the i-th opening in the i-th focusing material layer;

[0030] Filling the i+1th focusing material layer with a thickness of the i+1th thickness in the i-th opening; the i-th thickness is greater than the i+1th thickness;

[0031] When i is equal to N-1, the Nth focusing material layer filled in the N-1th opening is the Nth stepped structure.

[0032] Optionally, after forming the stacked functional layer and before forming the ultrasonic focusing matching layer, the method further includes:

[0033] The stacked functional layer is preprocessed so that the size of the stacked functional layer is a preset size.

[0034] Optionally, after forming the stacked functional layer and before forming the ultrasonic focusing matching layer, the method further includes:

[0035] providing a first electrode lead and a second electrode lead;

[0036] One end of the first electrode lead is fixed to a side of the ultrasonic focusing matching layer close to the piezoelectric layer, and one end of the second electrode lead is fixed to a side of the conductive backing away from the piezoelectric layer.

[0037] The technical solution of the present invention is to provide a stepped groove on the surface of the ultrasonic focusing matching layer on the ultrasonic transducer away from the piezoelectric layer, and the stepped groove includes a plurality of stepped structures, so that when the ultrasonic wave reaches the ultrasonic focusing matching layer, the refraction principle of sound propagation can be utilized to enable the ultrasonic wave to be focused in the ultrasonic focusing matching layer provided with the stepped groove, thereby reducing the diffusion of the ultrasonic beam and increasing the power of the ultrasonic wave. Therefore, when the focused ultrasonic signal propagates to the piezoelectric layer, it is ensured that the piezoelectric layer can accurately identify the ultrasonic signal and convert the ultrasonic signal into an electrical signal, so that the ultrasonic transducer has a good focusing effect, so that when the ultrasonic transducer is applied to the fields of ultrasonic detection, ultrasonic imaging or ultrasonic therapy , and can have higher resolution and sensitivity; at the same time, by setting the bottom thickness of the step groove of the ultrasonic focusing matching layer to be greater than 0, the ultrasonic focusing matching layer has the function of impedance matching, so that the ultrasonic wave has a higher transmittance in the ultrasonic focusing matching layer, and the ultrasonic reflection is improved; in addition, since the surface of the ultrasonic focusing matching layer facing away from the piezoelectric layer is provided with a step groove, compared with the case where the step groove is set as a concave arc, the preparation process of the step groove is simple, and it can be prepared by cutting, ablation and other processes, which is conducive to simplifying the preparation process of the ultrasonic focusing matching layer, and then can simplify the overall structure of the ultrasonic transducer, and simplify the preparation process of the ultrasonic transducer, which is conducive to improving the production efficiency and production yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the structure of a super energy transducer provided by an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of the three-dimensional structure of an ultrasonic transducer provided in an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the structure of another ultrasonic transducer provided by an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the variation of the sound pressure of an ultrasonic transducer with distance provided by an embodiment of the present invention;

[0043] Figure 5 A flow chart of a method for preparing an ultrasonic transducer provided in an embodiment of the present invention;

[0044] Figure 6 A process flow chart of the preparation of an ultrasonic transducer provided in an embodiment of the present invention;

[0045] Figure 7 A flow chart of the process for preparing the ultrasonic focusing matching layer provided in an embodiment of the present invention;

[0046] Figure 8 A flow chart of a process for preparing N stepped structures provided in an embodiment of the present invention;

[0047] Fig. 9 A flow chart of a method for preparing N stepped structures provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0050] An embodiment of the present invention provides an ultrasonic transducer, which can be applied to fields such as ultrasonic detection, ultrasonic imaging, and ultrasonic therapy. Figure 1 A schematic diagram of the structure of an ultrasonic transducer provided in an embodiment of the present invention, Figure 2 A schematic diagram of the three-dimensional structure of an ultrasonic transducer provided in an embodiment of the present invention, referring to Figure 1 and Figure 2 As shown, the ultrasonic transducer includes: a stacked functional layer 1 and an ultrasonic focusing matching layer 2, wherein the stacked functional layer 1 includes a conductive backing 11 and a piezoelectric layer 12 that are stacked; the ultrasonic focusing matching layer 2 is located on the side of the piezoelectric layer 12 away from the conductive backing 11; a stepped groove 3 is provided on the surface of the ultrasonic focusing matching layer 2 on the side away from the piezoelectric layer 12; the stepped groove 3 includes a plurality of stepped structures 31.

[0051] Among them, the conductive backing 11 can carry and support the piezoelectric layer 12 and the ultrasonic focusing layer 2 located thereon, and also has a conductive function, so that the electrical signal can be transmitted to the piezoelectric layer 12 through the conductive backing 11, or the electrical signal generated by the piezoelectric layer 12 can be transmitted to other devices electrically connected to it through the conductive backing 11; the piezoelectric layer 12 is used to convert ultrasonic energy entering from the outside into electrical energy, or to convert electrical energy into ultrasonic energy; the ultrasonic focusing matching layer 2 can focus ultrasonic waves, so that the ultrasonic signals entering from the outside can have a smaller diffusion angle after passing through the ultrasonic focusing matching layer 2, thereby improving the resolution and sensitivity of the ultrasonic transducer; at the same time, the ultrasonic focusing matching layer 2 can also perform impedance matching with the piezoelectric layer 12, so that the ultrasonic wave has a higher transmittance in the ultrasonic focusing matching layer, thereby improving ultrasonic reflection.

[0052] Specifically, refer to Figure 1As shown, the ultrasonic transducer provided by the embodiment of the present invention can receive ultrasonic waves and convert the received ultrasonic waves. It can be especially applied to intravascular detection and imaging, receive ultrasonic waves reflected in the blood vessels, and realize the detection of vascular lesions. The ultrasonic wave enters from the side of the ultrasonic focusing matching layer 2 away from the piezoelectric layer 12. Since the surface of the side of the ultrasonic focusing matching layer 2 away from the piezoelectric layer 12 is provided with a stepped groove 3, and the stepped groove 3 includes a plurality of stepped structures 31, the ultrasonic wave can be refracted on each stepped structure 31 of the stepped groove 3. After multiple refractions, the dispersed ultrasonic waves will be focused into an ultrasonic beam with a smaller diffusion angle, thereby realizing the focusing of the ultrasonic wave. The focused ultrasonic wave will pass through the ultrasonic focusing matching layer 2 to reach the piezoelectric layer 12, so that the focused ultrasonic wave energy is converted into electrical energy through the piezoelectric layer 12, and the electrical energy can be output through the conductive backing 11, realizing the conversion of ultrasonic wave energy into electrical energy.

[0053] It is understandable that the above is only an exemplary description of the ultrasonic transducer provided in the embodiment of the present invention that can receive ultrasonic waves. In the embodiment of the present invention, the ultrasonic transducer can also emit ultrasonic waves, that is, by applying an electrical signal with a certain frequency and amplitude to the piezoelectric layer 12, so that the piezoelectric layer 12 can convert the electrical signal into ultrasonic waves. At this time, the ultrasonic wave can be directionally emitted after being focused by the ultrasonic focusing matching layer 2, for example, it can act on the lesion to achieve the purpose of treatment. On the premise that the core invention point of the embodiment of the present invention can be achieved, the embodiment of the present invention does not limit the application scenario of the ultrasonic transducer. For the convenience of description, without special limitations, the embodiments of the present invention take the ultrasonic transducer as an example of receiving ultrasonic waves and converting them into electrical energy to exemplify the technical solutions of the embodiments of the present invention.

[0054] In addition, since the thickness of each position of the ultrasonic focusing matching layer 2 is not 0, each position of the ultrasonic focusing matching layer 2 has a certain impedance, and the piezoelectric layer 12 itself also has a certain thickness, so that the piezoelectric layer 12 also has a certain impedance, and the impedance of the ultrasonic focusing matching layer 2 and the impedance of the piezoelectric layer 12 are related to their respective materials. Therefore, in order to make the ultrasonic wave have a higher transmittance in the ultrasonic focusing matching layer 2 and have a smaller reflection after reaching the piezoelectric layer 12, the impedance of the ultrasonic focusing matching layer 2 can be matched with the impedance of the piezoelectric layer 12 itself, so that the ultrasonic wave reaching the piezoelectric layer 12 and converted by the piezoelectric layer 12 has a higher capacity, thereby improving the resolution and sensitivity of the ultrasonic transducer, and then when the ultrasonic transducer is used for ultrasonic detection or ultrasonic imaging, the accuracy of the ultrasonic detection result or the clarity of the ultrasonic imaging can be improved.

[0055] In an optional embodiment, when the impedance of the object to be tested is known to be Z L , the impedance of the piezoelectric layer 12 is Z0 When Determine the impedance Z of the ultrasonic focusing matching layer 2 1 , so that the impedance of the ultrasonic focusing matching layer 2 can form a good impedance match with the object to be measured and the piezoelectric layer, so that the ultrasonic transducer has a better focusing effect, higher resolution and sensitivity.

[0056] Optionally, the material of the ultrasonic focusing matching layer 2 may include polyparaxylene, so that the ultrasonic focusing matching layer 2 can be formed under a low-temperature processing technology. At the same time, polyparaxylene has a high transmittance, so that the ultrasonic wave can have a high transmittance when passing through the ultrasonic focusing matching layer 2, thereby ensuring that the ultrasonic wave reaching the piezoelectric layer has a higher energy.

[0057] In an optional embodiment, the minimum thickness T2 of the ultrasonic focusing matching layer 2 satisfies: T2 = C / F / 4*λ; wherein C is the propagation velocity of the ultrasonic wave in the ultrasonic focusing matching layer 2, F is the operating frequency of the ultrasonic transducer, and λ is the wavelength of the ultrasonic wave. In this way, by making the minimum thickness T2 of the ultrasonic focusing matching layer 2 related to 1 / 4 wavelength of the ultrasonic wave, and at the same time, also related to the propagation velocity C of the ultrasonic wave in the ultrasonic focusing matching layer 2 and the operating frequency F of the ultrasonic transducer, the reflection during the ultrasonic wave transmission process is reduced, so that the ultrasonic wave has a higher transmittance in the ultrasonic focusing matching layer 2, ensuring that the ultrasonic wave reaching the piezoelectric layer 12 has a higher energy and a smaller diffusion angle, thereby improving the resolution and sensitivity of ultrasonic detection, and improving the clarity of ultrasonic imaging.

[0058] The technical solution of the embodiment of the present invention is to set a stepped groove on the surface of the side of the ultrasonic focusing matching layer on the ultrasonic transducer away from the piezoelectric layer, and the stepped groove includes a plurality of stepped structures, so that when the ultrasonic wave reaches the ultrasonic focusing matching layer, the refraction principle of sound propagation can be utilized to change the transmission path of the ultrasonic wave in the ultrasonic focusing matching layer provided with the stepped groove, so that the ultrasonic wave is finally focused in space, the diffusion angle of the ultrasonic beam is reduced, and the power of the ultrasonic wave and the resolution of the image are improved, so that when the focused ultrasonic signal is propagated to the piezoelectric layer, it is ensured that the piezoelectric layer can accurately identify the ultrasonic signal and convert the ultrasonic signal into an electrical signal, so that the ultrasonic transducer has a good focusing effect, so that when the ultrasonic transducer is applied to ultrasonic In the field of detection, ultrasonic imaging or ultrasonic therapy, it can have higher resolution and sensitivity; at the same time, by setting the bottom thickness of the step groove of the ultrasonic focusing matching layer to be greater than 0, the ultrasonic focusing matching layer has the function of impedance matching, so that the ultrasonic wave has a higher transmittance in the ultrasonic focusing matching layer, and the ultrasonic reflection is improved; in addition, since the surface of the ultrasonic focusing matching layer facing away from the piezoelectric layer is provided with a step groove, compared with the case where it is set as a concave arc, the preparation process of the step groove is simple, and it can be prepared by cutting, ablation and other processes, which is conducive to simplifying the preparation process of the ultrasonic focusing matching layer, and then can simplify the overall structure of the ultrasonic transducer, and simplify the preparation process of the ultrasonic transducer, which is conducive to improving production efficiency and production yield.

[0059] It should be noted that Figure 1 and Figure 2 It is only exemplarily shown that the step groove includes three step structures. In the embodiment of the present invention, the step structure of the step groove can be 2, 3 or more than 3. Under the dual considerations of good focusing performance and simple process flow, the number of step structures set in the step groove can be selected according to actual needs, and the embodiment of the present invention does not make specific limitations on this.

[0060] Optional, continue to refer to Figure 1 and Figure 2 Each step structure 31 includes a step table 311 and a step side 312 that are connected and not coplanar; for the same step structure 31, the step table 311 and the step side 312 have a first common edge 313; at least one point on the first common edge 313 of each step structure 31 is located on the same arc 4.

[0061] Specifically, Figure 1In the cross-sectional view of the ultrasonic transducer shown, there is a point on the same arc 4 on the first common side 313 of each step structure 31, and the arc 4 is bent toward one side of the piezoelectric layer 12, so that each step structure 31 can be approximately fitted into an arc-shaped groove, that is, the height of each step structure gradually increases from the center to both sides of the ultrasonic focusing matching layer 2. In this way, the surface of the step structure 31 propagating ultrasonic waves to the ultrasonic focusing matching layer 2 can be refracted toward the center of the ultrasonic focusing matching layer 2 to achieve the effect of ultrasonic focusing.

[0062] Optional, continue to refer to Figure 1 , the ratio of the widths of the step terraces 311 in two adjacent step structures 31 is K; wherein 1≤K≤5.

[0063] Specifically, the value range of the ratio K of the widths of the step terraces 311 in two adjacent step structures 31 is [1,5]. When this value range is set, the preparation process can be simplified and a better focusing effect can be achieved. If K<1, that is, the size difference between the two adjacent step terraces 311 is not large, this structure will result in a larger ratio between the step terrace 311 and its height of one of the two adjacent step structures 31, and the process accuracy requirements for manufacturing the step structure 31 are high, which increases the difficulty of the preparation process of the ultrasonic transducer. Therefore, the width ratio K of the two adjacent step terraces 311 is usually set to ≥1, which is conducive to reducing the process difficulty, thereby reducing production costs, and improving production efficiency and yield; in addition, when K≤5, the size difference between the step surfaces of the two adjacent step structures is small, and more step structures can be set in the step groove, so that the fitting shape of each step structure can be closer to a concave arc, and more first common edges can be present in the step groove. When there is a point on the arc 4 on each first common edge, it can be ensured that more points are located on the arc 4, so that the ultrasonic wave has a better focusing effect in the ultrasonic focusing matching layer, improves the resolution and sensitivity of ultrasonic detection, and improves the clarity of ultrasonic imaging.

[0064] Optional, continue to refer to Figure 1 The step groove 3 also includes a step groove bottom surface 32 intersecting with each step side surface 313; the step groove bottom surface 32 is tangent to the arc 4. In this way, it can be ensured that at least one point on the step groove bottom surface 32 is located on the arc 4, so that the ultrasonic wave has a higher focusing effect in the ultrasonic focusing matching layer 2, improves the resolution and sensitivity of ultrasonic detection, and improves the clarity of ultrasonic imaging.

[0065] Optionally, the curvature radius ROC of the arc 4 has a value range of 5 mm ≤ ROC ≤ 25 mm. In this way, the curvature radius ROC of the arc 4 can be within this range, which can ensure that the ultrasound has a good focusing effect, further improve the resolution and sensitivity of ultrasound detection, and improve the clarity of ultrasound imaging.

[0066] Optional, continue to refer to Figure 1 , each step structure 31 of the step groove 3 is symmetrically distributed along the central axis of the ultrasonic focusing matching layer 2. In this way, the ultrasonic waves on both sides of the central axis of the ultrasonic focusing matching layer 2 can be focused near the central axis, so that when the ultrasonic transducer is used for ultrasonic imaging, the symmetry of the final imaging can be guaranteed; at the same time, the step groove 3 with a symmetrical structure can achieve a better sound beam focusing effect, further improving the sensitivity and resolution of the ultrasonic transducer. In addition, when designing an ultrasonic transducer, the design of a symmetrical structure is simple, and it is also more convenient for process processing, reducing the difficulty of process processing.

[0067] Optionally, the value range of the groove bottom thickness T1 of the stepped groove 3 is: λ / 8≤T1≤3λ / 4; λ is the wavelength of the ultrasonic wave.

[0068] Specifically, a certain thickness value will be set at the bottom of the step groove 3 to ensure that the ultrasonic wave can produce a certain focusing effect and impedance matching effect when passing through the ultrasonic focusing matching layer 2, minimize the energy attenuation loss of the ultrasonic signal, and make the focused ultrasonic wave have a higher energy when it reaches the surface of the piezoelectric layer 12, which is beneficial to improve the resolution and sensitivity of ultrasonic detection and improve the clarity of ultrasonic imaging. Among them, when the groove bottom thickness T1 of the step groove 3 is set to an integer multiple of λ / 4, the ultrasonic wave has the highest transmittance at the bottom of the step groove 3. Limited by the requirements of process accuracy, the groove bottom thickness of the step groove 3 can fluctuate up and down in a small range near the λ / 4 value. Therefore, an upper and lower limit value is set near the standard range, so that the ultrasonic wave can produce a better focusing effect and a higher transmittance within this range, meeting the high-precision detection requirements and high-definition imaging requirements.

[0069] Optional, Figure 3 A schematic diagram of another ultrasonic transducer provided in an embodiment of the present invention, referring to Figure 3 As shown, the stacked functional layer 1 further includes at least one impedance matching layer 13 ; the impedance matching layer 13 is located between the ultrasonic focusing matching layer 2 and the piezoelectric layer 12 .

[0070] Specifically, the ultrasonic focusing matching layer 2 itself has the function of impedance matching, but since the materials of the ultrasonic focusing matching layer 2 and the piezoelectric layer 12 are selected differently, impedance matching cannot meet higher impedance matching requirements only by setting the thickness of the ultrasonic focusing matching layer 2. At this time, at least one impedance matching layer 13 can be set between the ultrasonic focusing matching layer 2 and the piezoelectric layer 12, so that the ultrasonic focusing matching layer 2 and the impedance matching layer 13 are combined to perform impedance matching with the piezoelectric layer 12, further reducing reflections during ultrasonic propagation, improving the accuracy of ultrasonic detection, making the ultrasonic transducer have higher sensitivity and resolution, and improving the clarity of ultrasonic imaging.

[0071] It should be noted that the impedance matching layer 13 can be provided with one layer or multiple layers. Providing one layer of impedance matching layer 13 is equivalent to achieving double-layer impedance matching; similarly, providing two layers of impedance matching layer 13 is equivalent to achieving three-layer impedance matching, and so on. The specific number of impedance matching layers 13 is determined according to actual conditions, and this embodiment does not impose any restrictions on this.

[0072] In an optional embodiment, when the impedance of the object to be tested is known to be Z L , the impedance of the piezoelectric layer 12 is Z 0 When Determine the impedance Z of the ultrasonic focusing matching layer 2 1 , and according to Determine the impedance Z of the impedance matching layer 13 2 Thus, according to the impedance Z of the piezoelectric layer 12 0 and the impedance Z of the object under test L Determine the impedance Z of the ultrasonic focusing matching layer 2 1 and the impedance Z of the impedance matching layer 13 2 value, and based on this, the materials and thicknesses of the ultrasonic focusing matching layer 2 and the impedance matching layer 13 are selected so that the ultrasonic transducer has a better focusing effect, higher resolution and sensitivity.

[0073] Optional, continue to refer to Figure 1 The ultrasonic transducer further includes: a first electrode lead 5 and a second electrode lead 6 arranged on opposite sides of the stacked functional layer 1 , and the first electrode lead 5 is connected to the ultrasonic focusing matching layer 2 , and the second electrode lead 6 is connected to the conductive backing 1 .

[0074] Among them, one of the first electrode lead 5 and the second electrode lead 6 is a positive electrode lead, and the other is a negative electrode lead. In an optional embodiment, the first electrode lead 5 can be a positive electrode lead, and the second electrode lead 6 can be a negative electrode lead. The material of the first electrode lead 5 and the second electrode lead 6 can be silver-plated copper wire or galvanized copper wire to ensure that the first electrode lead 5 and the second electrode lead 6 have good electrical conductivity. One end of the first electrode lead 5 can be arranged between the ultrasonic focusing matching layer 2 and the stacked functional layer 1, and the other end of the first electrode lead 5 can extend toward the side away from the ultrasonic focusing matching layer 2 and the stacked functional layer 1, so that the first electrode lead 5 can be connected to an external device or equipment; similarly, one end of the second electrode lead 6 can be fixed to the side of the conductive backing 11 away from the piezoelectric layer 12, and the other end of the second electrode lead 6 extends in a direction parallel to the extension direction of the first electrode lead 5, so that the second electrode lead 6 can also be connected to an external device or equipment; at the same time, the first electrode lead 5 and the second electrode lead 6 can be electrically connected to the positive and negative electrodes of the external device or equipment, respectively, so as to form a conductive circuit, so that electrons can be transmitted in the conductive circuit.

[0075] Specifically, the first electrode lead 5 is connected to the ultrasonic focusing matching layer 2, and the second electrode lead 6 is connected to the conductive backing 1, so that when the ultrasonic wave passes through the ultrasonic focusing matching layer 2, the sound beam can be focused in the ultrasonic focusing matching layer 2, and the ultrasonic wave after focusing reaches the piezoelectric layer 12, and the piezoelectric layer 12 converts the received ultrasonic wave signal into an electrical signal to generate directionally moving carriers, which can move directionally between the first electrode lead 5 and the second electrode lead 6, thereby generating a potential difference between the first electrode lead 5 and the second electrode lead 6, and the device or equipment electrically connected to the first electrode lead 5 and the second electrode lead 6 can detect the potential difference, thereby realizing the detection of the ultrasonic wave.

[0076] The sound pressure of the ultrasonic transducer provided by the embodiment of the present invention varies with distance. Figure 4 As shown, within each distance range, the sound pressure of the ultrasonic transducer has a certain fluctuation, but the sound pressure fluctuation within each distance range is relatively small, so that the ultrasonic transducer provided in the embodiment of the present invention has a higher focusing ability, meets the detection requirements of high sensitivity and high resolution, and ensures that the ultrasonic imaging has a higher clarity.

[0077] Based on the same inventive concept, an embodiment of the present invention further provides a method for preparing an ultrasonic transducer. Figure 5 A flowchart of a method for preparing an ultrasonic transducer provided in an embodiment of the present invention, Figure 6 The process flow chart of the ultrasonic transducer provided in the embodiment of the present invention is shown in FIG. Figure 5 and Figure 6As shown, the method is performed by any of the above-mentioned structures of the ultrasonic transducer. It includes:

[0078] S110 , forming a stacked functional layer.

[0079] The stacked functional layer includes a conductive backing and a piezoelectric layer which are stacked.

[0080] Specifically, refer to Figure 6 As shown, when preparing the stacked functional layer, a conductive backing 11 may be provided first, and a piezoelectric layer 12 may be formed on one side surface of the conductive backing 11 by a preparation process such as deposition.

[0081] S120, forming an ultrasonic focusing matching layer on a side of the piezoelectric layer facing away from the conductive backing.

[0082] Wherein, a step groove is arranged on a side of the ultrasonic focusing matching layer away from the piezoelectric layer; the step groove includes a plurality of step structures.

[0083] For details, please refer to Figure 6 The material of the ultrasonic focusing matching layer may include but is not limited to polyparaxylene. The ultrasonic focusing matching material layer is formed by deposition, electroplating or evaporation on the surface of the piezoelectric layer 12 on the side away from the conductive backing 11, and a step groove containing multiple step structures is formed on the surface of the ultrasonic focusing matching material layer on the side away from the piezoelectric layer 12 by cutting, etching or ablation, thereby preparing the ultrasonic focusing matching layer 2.

[0084] The method for preparing the ultrasonic transducer provided in the embodiment of the present invention is performed by the ultrasonic transducer structure provided in the embodiment of the present invention, has the technical features of the ultrasonic transducer provided in the embodiment of the present invention, and can achieve the same beneficial effects as the ultrasonic transducer provided in the embodiment of the present invention. The similarities are referred to the above description and will not be repeated here.

[0085] Optionally, forming an ultrasonic focusing matching layer on a side of the piezoelectric layer away from the conductive backing includes: sequentially forming N step structures on a side of the piezoelectric layer away from the conductive backing, wherein the i-th step structure surrounds the i+1-th step structure, and the height of the i-th step structure is greater than the height of the i+1-th step structure; each step structure constitutes an ultrasonic focusing matching layer; N is a positive integer greater than or equal to 2, and i is a positive integer less than N.

[0086] Specifically, Figure 7 The flowchart of the preparation process of the ultrasonic focusing matching layer provided in the embodiment of the present invention is shown in FIG. Figure 7As shown, when i=1, i+1=2, a first step structure with a certain height is formed on the surface of the piezoelectric layer 12 away from the conductive backing by deposition, electroplating or evaporation, and the first step structure is arranged on the surface of the piezoelectric layer 12, surrounding the surface of the piezoelectric layer 12, and has a certain height; after the first step structure is formed, the center of the first step structure is a hollow structure, and a second step structure with a certain height can be formed at the center of the first step structure by deposition, electroplating or evaporation, and the height of the second step structure is less than the height of the first step structure. In this way, a step groove with a two-layer step structure is formed, that is, an ultrasonic focusing matching layer 2 with a two-layer step structure is formed; when i=2, i+1=3, at this time, after the second step structure is formed, the center of the second step structure is a hollow structure, and a third step structure can be formed at the center of the second step structure by deposition, electroplating or evaporation, so that the second step structure surrounds the third step structure, and the height of the third step structure is less than the height of the second step structure.

[0087] It should be noted that the above is only an example of an embodiment of the present invention in which three step structures are provided in the step groove. When the step groove includes more step structures, i=3, 4, ... can be continued, so that an ultrasonic focusing matching layer 2 including more than three step structures can be obtained.

[0088] Optional, Figure 8 A flowchart of a process for preparing N stepped structures provided in an embodiment of the present invention, Fig. 9 The flowchart of the method for preparing N step structures provided in the embodiment of the present invention is shown in FIG. Figure 8 and Fig. 9 As shown, N stepped structures are sequentially formed on the side of the piezoelectric layer facing away from the conductive backing, including:

[0089] S121. Form an i-th focusing material layer with an i-th thickness on the side of the piezoelectric layer facing away from the conductive backing.

[0090] Specifically, taking i=1 as an example, a first focusing material layer with a first thickness can be formed on the surface of the piezoelectric layer 12 on the side of the piezoelectric layer 12 away from the conductive backing 11 by deposition, electroplating, or evaporation.

[0091] S122, patterning the i-th focusing material layer to form an i-th opening and an i-th stepped structure surrounding the i-th opening in the i-th focusing material layer.

[0092] Specifically, after a first focusing material layer with a first thickness is formed on the surface of the piezoelectric layer 12 facing away from the conductive backing 11, the first focusing material layer is patterned, that is, the first focusing material layer is patterned by using processes such as laser cutting, physical cutting, etching or ablation to remove the middle part of the first focusing material layer to expose the middle piezoelectric layer 12 and retain the peripheral part of the first focusing material layer, thereby forming a first opening and a first stepped structure in the first focusing material layer.

[0093] S123, filling the i+1th focusing material layer with a thickness of the i+1th thickness in the i-th opening.

[0094] Among them, the i-th thickness is greater than the i+1-th thickness.

[0095] Specifically, after the first stepped structure is formed, a second focusing material layer with a second thickness can be filled on the surface of the piezoelectric layer 12 in the first opening by deposition, electroplating or evaporation processes, and the thickness of the filled second focusing material layer must be smaller than the thickness of the first focusing material layer, so that the second focusing material layer and the first stepped structure form a groove with a step.

[0096] Correspondingly, when i=2, i+1=3, that is, after the second focusing material layer is filled in the first opening, the second focusing material layer can be patterned to form a second opening and a second stepped structure around the second opening; after the second opening is formed, a third focusing material layer with a third thickness can be filled in the second opening, and the third thickness is less than the second thickness, thereby forming a stepped groove with three steps. The second focusing material layer and the third focusing material layer can be formed in a similar manner to the first focusing material layer, and the second focusing material layer can be patterned in a similar manner to the first focusing material layer. The similarities can be referred to the above description and will not be repeated here.

[0097] It can be understood that when i is equal to N-1, the Nth focusing material layer filled in the N-1th opening is the Nth stepped structure, that is, the Nth focusing material layer filled for the last time is no longer patterned, so that the bottom thickness of the formed stepped groove is not 0.

[0098] It should be noted that the above is only exemplary, and an exemplary description is given of an example in which the step groove includes three step structures. In an embodiment of the present invention, for the preparation method of more than three step structures, for example, four step structures, after forming a third focusing material layer with a thickness of the third thickness, the third focusing material layer can be patterned by laser cutting, physical cutting, ablation or etching, etc., to remove the middle part of the third focusing material layer, retain the third focusing material layer part around, and form a third opening and a third step structure; and so on, a multi-layer step structure can be obtained through this preparation process, and the thickness of each layer of the step structure decreases successively. The more step structures there are, the more the connecting lines between the step structures are similar to an arc shape, the better the focusing effect of the ultrasonic focusing matching layer formed by the multi-layer step structure, and the higher the detection sensitivity and imaging clarity.

[0099] Optionally, after forming the stacked functional layer and before forming the ultrasonic focusing matching layer, the method further includes: pre-processing the stacked functional layer so that the size of the stacked functional layer is a preset size.

[0100] Specifically, the method of pre-processing the stacked functional layer may include but is not limited to grinding, cutting, etc., which is not limited in this embodiment. By pre-processing the stacked functional layer so that the stacked functional layer has a certain preset size, it can be ensured that the ultrasonic focusing matching layer formed on the surface of the stacked functional layer also has a certain size, so that the ultrasonic transducer has a certain size after being obtained, so that the ultrasonic transducer can be used in the fields of ultrasonic detection, ultrasonic therapy or ultrasonic imaging.

[0101] Optionally, after forming the stacked functional layer and before forming the ultrasonic focusing matching layer, it also includes: providing a first electrode lead and a second electrode lead; fixing one end of the first electrode lead to a side of the ultrasonic focusing matching layer close to the piezoelectric layer, and fixing one end of the second electrode lead to a side of the conductive backing away from the piezoelectric layer.

[0102] Specifically, the materials of the first electrode lead and the second electrode lead may include but are not limited to silver-plated copper wire or galvanized copper wire, and the first electrode lead and the second electrode lead may be attached to opposite sides of the stacked functional layer by welding or conductive silver paste, so that the first electrode lead can be connected to the ultrasonic focusing matching layer on the side of the piezoelectric layer away from the conductive backing, and the second electrode lead can be connected to the conductive backing on the side of the piezoelectric layer away from the ultrasonic focusing matching layer. Specifically, one end of the first electrode lead may be fixed to the side of the ultrasonic focusing matching layer close to the piezoelectric layer, and one end of the second electrode lead may be fixed to the side of the conductive backing away from the piezoelectric layer, and this embodiment does not limit this.

[0103] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An ultrasonic transducer, It is characterized in that include: A stacked functional layer, the stacked functional layer comprising a conductive backing and a piezoelectric layer stacked in layers; An ultrasonic focusing matching layer, located on a side of the piezoelectric layer away from the conductive backing; A stepped groove is arranged on a surface of the ultrasonic focusing matching layer on a side facing away from the piezoelectric layer; the stepped groove includes a plurality of stepped structures.

2. The ultrasonic transducer according to claim 1, It is characterized in that Each of the step structures comprises a step table and a step side surface which are connected and not coplanar; for the same step structure, the step table and the step side surface have a first common edge; At least one point on the first common side of each of the step structures is located on the same arc.

3. The ultrasonic transducer according to claim 2, It is characterized in that The ratio of the widths of the step terraces in two adjacent step structures is K; Among them, 1≤K≤5.

4. The ultrasonic transducer according to claim 2, It is characterized in that The step groove further includes a step groove bottom surface intersecting with each of the step side surfaces; the step groove bottom surface is tangent to the circular arc.

5. The ultrasonic transducer according to claim 2, It is characterized in that The value range of the radius of curvature ROC of the circular arc is: 5mm≤ROC≤25mm.

6. The ultrasonic transducer according to claim 1, It is characterized in that The steps of the stepped groove are distributed.

7. The ultrasonic transducer according to claim 1, It is characterized in that The thickness T1 of the bottom of the stepped groove has a value range of λ / 8≤T1≤3λ / 4, where λ is the wavelength of the ultrasonic wave.

8. The ultrasonic transducer according to claim 1, It is characterized in that Also includes: A first electrode lead and a second electrode lead are disposed on opposite sides of the stacked functional layer, wherein the first electrode lead is connected to the ultrasonic focusing matching layer, and the second electrode lead is connected to the conductive backing.

9. The ultrasonic transducer according to claim 1, It is characterized in that The minimum thickness T2 of the ultrasonic focusing matching layer satisfies: T2=C / F / 4*λ; Wherein, C is the propagation velocity of the ultrasonic wave in the ultrasonic focusing matching layer, F is the operating frequency of the ultrasonic transducer, and λ is the wavelength of the ultrasonic wave.

10. The ultrasonic transducer according to claim 1, It is characterized in that The material of the ultrasonic focusing matching layer includes polyparaxylene.

11. The ultrasonic transducer according to claim 1, It is characterized in that The stacked functional layer further includes at least one impedance matching layer; The impedance matching layer is located between the ultrasonic focusing matching layer and the piezoelectric layer.

12. A method for preparing an ultrasonic transducer, It is characterized in that include: Forming a stacked functional layer; the stacked functional layer includes a conductive backing and a piezoelectric layer stacked; forming an ultrasonic focusing matching layer on a side of the piezoelectric layer facing away from the conductive backing; A step groove is provided on a side of the ultrasonic focusing matching layer away from the piezoelectric layer; the step groove includes a plurality of step structures.

13. The method for preparing an ultrasonic transducer according to claim 12, It is characterized in that An ultrasonic focusing matching layer is formed on a side of the piezoelectric layer facing away from the conductive backing, comprising: N stepped structures are formed in sequence on the side of the piezoelectric layer away from the conductive backing; wherein the i-th stepped structure surrounds the i+1-th stepped structure, and the height of the i-th stepped structure is greater than the height of the i+1-th stepped structure; each of the stepped structures constitutes the ultrasonic focusing matching layer; N is a positive integer greater than or equal to 2, and i is a positive integer less than N.

14. The method for preparing an ultrasonic transducer according to claim 13, It is characterized in that N stepped structures are sequentially formed on a side of the piezoelectric layer away from the conductive backing, including: forming an i-th focusing material layer having an i-th thickness on a side of the piezoelectric layer facing away from the conductive backing; Patterning the i-th focusing material layer to form an i-th opening and an i-th stepped structure surrounding the i-th opening in the i-th focusing material layer; Filling the i+1th focusing material layer with a thickness of the i+1th thickness in the i-th opening; the i-th thickness is greater than the i+1th thickness; When i is equal to N-1, the Nth focusing material layer filled in the N-1th opening is the Nth stepped structure.

15. The method for preparing an ultrasonic transducer according to claim 12, It is characterized in that After forming the stacked functional layer and before forming the ultrasonic focusing matching layer, the method further includes: The stacked functional layer is preprocessed so that the size of the stacked functional layer is a preset size.

16. The method for preparing an ultrasonic transducer according to claim 12, It is characterized in that After forming the stacked functional layer and before forming the ultrasonic focusing matching layer, the method further includes: providing a first electrode lead and a second electrode lead; One end of the first electrode lead is fixed to a side of the ultrasonic focusing matching layer close to the piezoelectric layer, and one end of the second electrode lead is fixed to a side of the conductive backing away from the piezoelectric layer.

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