Anti-electromagnetic interference piezoelectric ultrasonic transducer

Abstract

The utility model relates to an anti-electromagnetic interference piezoelectric ultrasonic transducer which comprises a shell, a matching layer is arranged in the shell, a composite piezoelectric ceramic layer is arranged on the matching layer, an electrode layer is connected to the composite piezoelectric ceramic layer, a PCB layer is connected to the electrode layer, an electrode lead is connected to the electrode layer, and the electrode lead is connected to a circuit system through the PCB layer; and a shielding layer is arranged between the matching layer and the composite piezoelectric ceramic layer, is communicated with the composite piezoelectric ceramic layer and is grounded through an electrode lead. According to the anti-electromagnetic interference piezoelectric ultrasonic transducer, the shielding layer is arranged between the matching layer and the composite piezoelectric ceramic layer, and the shielding layer effectively isolates electromagnetic wave interference entering from a radiation end window of the ultrasonic imaging transducer, so that the ultrasonic imaging transducer is close to a complete electromagnetic shielding effect. The anti-electromagnetic interference piezoelectric ultrasonic transducer has the advantages that signals are stable, certain electromagnetic interference can be shielded, and therefore the good imaging effect is achieved.

Description

Technical Field

[0001] This application relates to the technical field of medical ultrasonic imaging, and particularly relates to a piezoelectric ultrasonic transducer with anti-electromagnetic interference. Background Art

[0002] In related technologies, an ultrasonic imaging transducer is the most important component of a B-mode ultrasonic diagnostic instrument. It converts an electrical signal into an acoustic signal, and the acoustic signal enters the human body or other objects. The echo generated when encountering different acoustic impedance layers is received and then converted back into an electrical signal to form a tomographic image of human tissue or object tissue, so as to judge what changes have occurred in the tissue or object. For example, whether there is a lesion in human tissue. The ultrasonic imaging transducer and the B-mode ultrasonic diagnostic instrument have become important means for hospitals to examine human diseases.

[0003] However, the electrical signal generated by the B-mode ultrasonic diagnostic instrument is subject to electromagnetic wave interference, which limits the diagnostic effect of the B-mode ultrasonic diagnostic instrument. Various shielding measures have been taken for the ultrasonic imaging transducer in the B-mode ultrasonic diagnostic instrument to resist electromagnetic wave interference. However, due to various technical reasons, the radiation end face of the ultrasonic imaging transducer has not been shielded so far, resulting in the direct exposure of the radiation end face of the ultrasonic imaging transducer to electromagnetic wave interference. The surrounding electromagnetic waves can directly enter the positive and negative electrodes of the ultrasonic imaging transducer, greatly reducing the anti-electromagnetic interference performance of the entire ultrasonic system and also reducing the diagnostic effect of the B-mode ultrasonic diagnostic instrument. Summary of the Invention

[0004] To overcome the problems existing in related technologies, this application provides a piezoelectric ultrasonic transducer with anti-electromagnetic interference, which has the advantages of stable signals, can shield a certain amount of electromagnetic interference, and thus achieves good imaging effects.

[0005] This application provides a piezoelectric ultrasonic transducer with anti-electromagnetic interference, including: a housing, a matching layer is provided inside the housing, a composite piezoelectric ceramic layer is provided on the matching layer, an electrode layer is connected to the composite piezoelectric ceramic layer, a PCB layer is connected to the electrode layer, an electrode lead is connected to the electrode layer, and the electrode lead is connected to a circuit system through the PCB layer; a shielding layer is provided between the matching layer and the composite piezoelectric ceramic layer, and the shielding layer is communicated with the composite piezoelectric ceramic layer and grounded through the electrode lead.

[0006] In the above piezoelectric ultrasonic transducer with anti-electromagnetic interference, the composite piezoelectric ceramic layer includes an epoxy resin material, and piezoelectric ceramic columns embedded in the epoxy resin material. The piezoelectric ceramic columns are vibration elements, and the PCB layer connects the vibration elements to the circuit system through the electrode leads.

[0007] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the shielding layer is a metal thin film bonded or plated between the matching layer and the composite piezoelectric ceramic layer. The shielding layer is connected to one end of the piezoelectric ceramic column and grounded through a grounding terminal lead.

[0008] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the PCB layer is provided with corresponding through holes above the vibration element, and the through holes are filled with a backing layer, and the backing layer absorbs the acoustic energy on the back of the composite piezoelectric ceramic layer.

[0009] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the backing layer is provided with a polymer and a filler. The polymer serves as a matrix, and the filler is mixed into the matrix.

[0010] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the polymer is one or more of silica gel, rubber, polyurethane, and epoxy resin.

[0011] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the filler is one or more of tungsten powder, tungsten oxide powder, iron oxide powder, aluminum oxide powder, and glass powder.

[0012] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the acoustic impedance of the matching layer is Z1, the acoustic impedance of the piezoelectric ceramic column is Z2, and the acoustic impedance of the load material is Z3. In order to match the acoustic impedance of the piezoelectric ceramic column and the epoxy resin material, the following conditions need to be met: Z1*Z1≈Z2*Z3.

[0013] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the thickness t of the matching layer is determined by the acoustic wavelength λ and satisfies t≈(n + 1 / 4)λ (n = 0, 1, 2...).

[0014] In the above piezoelectric ultrasonic transducer with electromagnetic interference resistance, the electrode layer uses gold, silver, copper, or nickel material, and a metal thin film is formed on the composite piezoelectric ceramic layer by physical vapor deposition or electroless plating.

[0015] The technical solution provided by this application may include the following beneficial effects: In this piezoelectric ultrasonic transducer with electromagnetic interference resistance, a shielding layer is provided between the matching layer and the composite piezoelectric ceramic layer. The shielding layer effectively isolates the electromagnetic wave interference entering from the radiation end window of the ultrasonic imaging transducer, making the ultrasonic imaging transducer approach a complete electromagnetic shielding effect. This piezoelectric ultrasonic transducer with electromagnetic interference resistance has stable signals, can shield a certain amount of electromagnetic interference, and thus has the advantage of good imaging effects.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. Description of the Drawings

[0017] The above and other objects, features, and advantages of the present application will become more apparent by describing the exemplary embodiments of the present application in more detail with reference to the accompanying drawings. In the exemplary embodiments of the present application, the same reference numerals generally represent the same components.

[0018] Figure 1 It is a schematic structural diagram of a piezoelectric ultrasonic transducer with anti-electromagnetic interference shown in an embodiment of the present application;

[0019] Figure 2 It is a schematic structural diagram of a partial cross-section of a composite piezoelectric ceramic layer of a piezoelectric ultrasonic transducer with anti-electromagnetic interference shown in an embodiment of the present application;

[0020] Figure 3 It is a schematic structural diagram of a perspective view of a composite piezoelectric ceramic layer of a piezoelectric ultrasonic transducer with anti-electromagnetic interference shown in an embodiment of the present application.

[0021] Reference numerals in the drawings:

[0022] Housing 1;

[0023] Matching layer 2;

[0024] Shielding layer 3;

[0025] Composite piezoelectric ceramic layer 4; Epoxy resin material 41; Piezoelectric ceramic column 42;

[0026] Electrode layer 5; First electrode layer 51; Second electrode layer 52;

[0027] PCB layer 6; Through-hole 61;

[0028] Electrode lead 7;

[0029] Backing layer 8. Detailed implementation manners

[0030] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0031] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a", "the", and "said" used in this application and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0032] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0033] The technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0034] Figure 1 It is a schematic structural diagram of a piezoelectric ultrasonic transducer with anti-electromagnetic interference shown in the embodiments of this application. Refer to Figure 1 A piezoelectric ultrasonic transducer with anti-electromagnetic interference, comprising: a housing 1, a matching layer 2 is provided inside the housing 1, a composite piezoelectric ceramic layer 4 is provided on the matching layer 2, an electrode layer 5 is connected to the composite piezoelectric ceramic layer 4, a PCB layer 6 is connected to the electrode layer 5, an electrode lead 7 is connected to the electrode layer 5, and the electrode lead 7 is connected to the circuit system through the PCB layer 6.

[0035] Refer to Figures 1 to 3 In some preferred embodiments, the composite piezoelectric ceramic layer 4 includes an epoxy resin material 41 and piezoelectric ceramic columns 42 embedded in the epoxy resin material 41. The epoxy resin material 41 forms an epoxy resin layer, and the piezoelectric ceramic columns 42 are embedded in the epoxy resin layer according to a certain pattern. The piezoelectric ceramic columns 42 are vibration elements, and the PCB layer 6 connects the vibration elements to the circuit system through the electrode leads 7. The piezoelectric ceramic columns 42 are embedded in the epoxy resin layer made of the epoxy resin material 41 according to a certain pattern. In a specific implementation, the two end faces of the piezoelectric ceramic columns 42 are respectively exposed outside the epoxy resin layer and are respectively connected to a first electrode layer 51 and a second electrode layer 52. In this embodiment, as Figure 2As shown, the first electrode layer 51 is an independent electrode for each piezoelectric ceramic column 42, and the second electrode layer 52 is a common electrode layer for multiple piezoelectric ceramic columns 42. The PCB layer 6 can connect the electrode leads 7 of each piezoelectric ceramic column 42 and each vibration element to the circuit system. In this embodiment, the common electrode layer is a ground electrode.

[0036] In this piezoelectric ultrasonic transducer with electromagnetic interference resistance, multiple piezoelectric ceramic columns 42 (vibration elements) are integrated into a system according to a certain rule, and each vibration element can input and output signals independently. A single transducer can achieve the functions that require multiple traditional ultrasonic transducers to cooperate, and realize the ultrasonic imaging function; if multiple such transducers are used in combination, a higher-precision imaging effect can be achieved. At the same time, the composite piezoelectric ceramic layer 4 uses 1-3 composite material, which has a very high electromechanical coupling coefficient in the thickness vibration direction. Compared with ordinary piezoelectric ceramics, it has the characteristics of high bandwidth and high sensitivity.

[0037] See Figure 1 , a shielding layer 3 is provided between the matching layer 2 and the composite piezoelectric ceramic layer 4. The shielding layer 3 is connected to the composite piezoelectric ceramic layer 4 and grounded through the electrode lead 7. In specific implementation, the shielding layer 3 is a metal thin film adhered or plated between the matching layer 2 and the composite piezoelectric ceramic layer 4. The shielding layer 3 is connected to one end of the piezoelectric ceramic column 42 and grounded through the ground lead. The material of the shielding layer 3 can be silver, copper, nickel, aluminum or gold, or a conductive adhesive mixed with these conductive metals and polymer materials, with a thickness of 0.1um to 50um. The shielding layer 3 must be a complete metal thin film without any missing or damaged parts, otherwise the shielding effect will be affected. The shielding layer 3 effectively isolates the electromagnetic wave interference entering from the radiation end window of the ultrasonic imaging transducer, making the ultrasonic imaging transducer approach a complete electromagnetic shielding effect. In this embodiment, the shielding layer 3 is a conductive silver glue, which is a mixture of conductive silver powder and epoxy resin, and is fixed between the matching layer 2 and the composite piezoelectric ceramic layer 4 by bonding, with a thickness of 20um. In this embodiment, when there is no shielding layer 3, the output signal will have a 30% amplitude fluctuation. After adding the shielding layer 3, no obvious signal fluctuation is observed. This piezoelectric ultrasonic transducer with electromagnetic interference resistance has the advantages of stable signal, can shield a certain amount of electromagnetic interference, and thus achieves a good imaging effect.

[0038] Preferably, see Figures 1 to 3, a corresponding via hole 61 is provided in the PCB layer 6 above the vibration element, and a backing layer 8 is poured into the via hole 61. The backing layer 8 absorbs the acoustic energy on the back of the composite piezoelectric ceramic layer 4, reducing the interference of the reflected acoustic wave on the back to ultrasonic imaging. It also requires a specific acoustic impedance to reduce acoustic wave reflection. Its main components are polymer and filler. The polymer serves as the matrix, and the filler is mixed into the matrix. The polymer is one or more of silicone, rubber, polyurethane, and epoxy resin. The filler is one or more of tungsten powder, tungsten oxide powder, iron oxide powder, aluminum oxide powder, and glass powder, and its function is to adjust the acoustic impedance of the backing layer 8 material to achieve the best performance. In this embodiment, the polymer matrix of the backing layer 8 is polyurethane, and the filler is tungsten powder, which is made by mixing in a ratio of 1:2.5. The backing layer 8 corresponds to the piezoelectric ceramic column 42 and is distributed in the PCB layer 6.

[0039] Specifically, referring to Figures 1 to 3 , the matching layer 2 is made of metal material, plastic material, or ceramic material. The matching layer 2 has a specific acoustic impedance and serves as a transition and match between the piezoelectric ceramic column 42 and the epoxy resin material 41 with a large difference in acoustic impedance, which can effectively improve the acoustic wave transmission ability and sensitivity. The acoustic impedance of the matching layer 2 is Z1, the acoustic impedance of the piezoelectric ceramic column 42 is Z2, and the acoustic impedance of the load material is Z3. In order to match the acoustic impedances of the piezoelectric ceramic column 42 and the epoxy resin material 41, the following condition needs to be satisfied: Z1*Z1≈Z2*Z3. In this embodiment, the acoustic impedance of the piezoelectric ceramic column 42 is 30Mrayl, the load material is water, and its acoustic impedance is 1.5Mrayl. The acoustic impedance of the matching layer 2 is 6.5Mrayl. The thickness t of the matching layer 2 is determined by the acoustic wave wavelength λ and satisfies t≈(n + 1 / 4)λ (n = 0, 1, 2...). In this embodiment, the thickness of the matching layer 2 is 425um.

[0040] In some embodiments, such as Figure 2 and Figure 3 shown, the composite piezoelectric ceramic layer 4 includes an epoxy resin layer and piezoelectric ceramic columns 42 embedded in the epoxy resin layer, and a first electrode layer 51 and a second electrode layer 52 provided on both end faces of the piezoelectric ceramic columns 42. The electrode layer 5 is made of gold, silver, copper, or nickel, and a metal thin film is formed on the composite piezoelectric ceramic layer 4 by physical vapor deposition method or electroless plating. The physical vapor deposition method can be vacuum ion plating or magnetron sputtering.

[0041] The embodiments of the present application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of technologies in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A piezoelectric ultrasonic transducer with anti-electromagnetic interference, characterized in that, Including: A housing, a matching layer is provided inside the housing, a composite piezoelectric ceramic layer is provided on the matching layer, an electrode layer is connected to the composite piezoelectric ceramic layer, a PCB layer is connected to the electrode layer, an electrode lead is connected to the electrode layer, and the electrode lead is connected to a circuit system through the PCB layer; A shielding layer is provided between the matching layer and the composite piezoelectric ceramic layer, and the shielding layer is communicated with the composite piezoelectric ceramic layer and grounded through the electrode lead.

2. The piezoelectric ultrasonic transducer against electromagnetic interference according to claim 1, wherein: The composite piezoelectric ceramic layer includes an epoxy resin material and piezoelectric ceramic columns embedded in the epoxy resin material. The piezoelectric ceramic columns are vibration elements, and the PCB layer connects the vibration elements to the circuit system through the electrode leads.

3. The piezoelectric ultrasonic transducer with electromagnetic interference resistance according to claim 2, characterized in that: The shielding layer is a metal thin film adhered or plated between the matching layer and the composite piezoelectric ceramic layer. The shielding layer is communicated with one end of the piezoelectric ceramic column and grounded through a grounding terminal lead.

4. The piezoelectric ultrasonic transducer with electromagnetic interference resistance according to claim 2, wherein: The PCB layer is provided with corresponding through holes above the vibration elements, and a backing layer is poured into the through holes. The backing layer absorbs the acoustic energy on the back surface of the composite piezoelectric ceramic layer.

5. The piezoelectric ultrasonic transducer for anti-electromagnetic interference according to claim 1, characterized in that: The electrode layer is made of gold, silver, copper or nickel, and a metal thin film is formed on the composite piezoelectric ceramic layer by physical vapor deposition or electroless plating.

Images