Ultrasonic transducer

Abstract

The utility model relates to the field of ultrasonic transducers, and provides an ultrasonic transducer, which comprises a conductive matching layer, a piezoelectric layer and a backing layer, the conductive matching layer covers the front end of the piezoelectric layer in all directions, the conductive matching layer is suitable for grounding conduction so as to enable interference signals on the front side and the side wall of the piezoelectric layer to flow to the ground, and the backing layer is arranged on the rear side of the piezoelectric layer. According to the ultrasonic transducer, the conductive matching layer covers the front end of the piezoelectric layer in all directions, the conductive matching layer is suitable for grounding conduction, and the conductive matching layer can enable electromagnetic interference signals on the front side and the side wall of the piezoelectric layer to flow to the ground, so that the stability and the reliability of the signals are improved; at the moment, the conductive matching layer is grounded and conducted to realize a shielding function, and a shielding layer does not need to be additionally arranged, so that relatively good anti-interference and shielding effects are achieved while relatively good acoustic performance is ensured.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic transducers, and further to an ultrasonic transducer. Background Technology

[0002] Medical ultrasound transducers are sensors that can convert electrical signals to ultrasound signals and vice versa, and are widely used in the field of medical ultrasound diagnosis. Medical ultrasound transducers must meet relevant electromagnetic compatibility (EMC) standards during operation to avoid significantly affecting the normal operation of other equipment, including medical devices, and to prevent easy interference from other electronic devices.

[0003] Currently, the conventional anti-interference measures for medical ultrasound transducers involve wrapping a layer of copper foil around the transducer and connecting it to the shielding ground. The transducer surface, i.e. the sound wave radiating surface, is not specially treated to avoid affecting the acoustic performance of the ultrasound pulse echo. Therefore, the transducer will inevitably receive some strong external interference signals, which may affect the ultrasound image.

[0004] To further enhance the EMC performance of the transducer, the thickness of the acoustic lens material in contact with human tissue is increased, and the casting / bonding is performed in two stages. After the first casting / bonding, a layer of conductive or conductive shielding material is bonded to the lens surface, followed by a second casting / bonding of the lens. As mentioned in patent CN200580010789.8, the thin metal layer is located on top of, around, or embedded in the transducer lens material. This shielding method inevitably has a certain impact on the transducer's acoustic performance and reliability: the increased thickness of the acoustic lens increases sound wave attenuation, affecting the transducer's acoustic performance; furthermore, the two-stage bonding / casting of the lens also affects the bonding strength between the two lens layers, making it prone to delamination between the lenses after prolonged movement and inspection of the transducer on the human body surface. Utility Model Content

[0005] To address the aforementioned technical problems, the purpose of this utility model is to provide an ultrasonic transducer in which a conductive matching layer fully covers the front end of the piezoelectric layer. The conductive matching layer is suitable for grounding and conduction, and can direct electromagnetic interference signals on the front and sidewalls of the piezoelectric layer to the ground, thereby improving signal stability and reliability. At this time, the conductive matching layer is grounded and conduction to achieve a shielding function, eliminating the need for an additional shielding layer. While ensuring good acoustic performance, it also provides good anti-interference and shielding effects.

[0006] To achieve the above objectives, this utility model provides an ultrasonic transducer, including a conductive matching layer, a piezoelectric layer, and a backing layer. The conductive matching layer covers the front end of the piezoelectric layer in all directions and is adapted to be grounded to direct interference signals on the front and sidewalls of the piezoelectric layer to the ground. The backing layer is disposed on the rear side of the piezoelectric layer.

[0007] In some embodiments, the conductive matching layer is formed by a composite of conductive filler and flexible polymer, and the conductive matching layer itself is adapted to conduct a connection to the shield ground and / or signal ground.

[0008] In some embodiments, the top and / or bottom surfaces of the conductive matching layer are plated with a conductive layer, and the conductive matching layer is adapted to conduct a connection between the shielding ground and / or the signal ground through the conductive layer.

[0009] In some embodiments, the conductive matching layer includes a first shielding portion and a second shielding portion. The first shielding portion is disposed on the front side of the piezoelectric layer and adapted to match the shape of the front side of the piezoelectric layer. The second shielding portion is adapted to cover the periphery of the front end of the piezoelectric layer, such that the first shielding portion and the second shielding portion can wrap around the front end of the piezoelectric layer.

[0010] In some embodiments, the second shielding portion includes a plurality of bonding portions, which are arranged sequentially at intervals around the edge of the first shielding portion. During the bonding process between the first shielding portion and the front side of the piezoelectric layer, the plurality of bonding portions are adapted to come close to each other and form a tight connection.

[0011] In some embodiments, the bonding portion includes a plurality of first bonding blocks and at least one second bonding block. The plurality of first bonding blocks are spaced apart on the two long sides of the piezoelectric layer, and a first gap is provided between adjacent first bonding blocks. The second bonding blocks are disposed on the two short sides of the piezoelectric layer, and a second gap is provided between the second bonding blocks and the first bonding blocks. The two sides of the second bonding block are adapted to be tightly connected to the first bonding blocks.

[0012] In some embodiments, the piezoelectric layer has a convex array structure, the first bonding block is an inverted trapezoid, the second bonding block is a fan shape, and the second bonding block includes a first part and a pair of second parts. The first part is adapted to be bonded to the short side of the piezoelectric layer, and the second part is adapted to be bonded to the long side of the piezoelectric layer and tightly connected to the first bonding block.

[0013] In some embodiments, a plurality of array elements are provided on the front side of the piezoelectric layer, and slits are provided between the plurality of array elements. The conductive matching layer can completely enclose the piezoelectric layer, so that an air gap structure is formed in the slits.

[0014] Compared with the prior art, the ultrasonic transducer provided by this utility model has at least one of the following beneficial effects:

[0015] 1. The conductive matching layer fully covers the front end of the piezoelectric layer. The conductive matching layer is suitable for grounding and conduction. The conductive matching layer can direct electromagnetic interference signals on the front and side walls of the piezoelectric layer to the ground, improving the stability and reliability of the signal. At this time, the conductive matching layer is grounded and conduction to achieve the shielding function. There is no need to set up an additional shielding layer. While ensuring good acoustic performance, it plays a good role in anti-interference and shielding.

[0016] 2. The first and second shielding parts can fully cover the front end of the piezoelectric layer. That is, the conductive matching layer wraps the top surface (sound wave radiation surface) and sides of the transducer 360 degrees, which plays a role in shielding external interference and reducing external radiation interference. This not only optimizes the acoustic and electrical performance, but also improves the stability and detection accuracy of the transducer.

[0017] 3. During the process of fitting the first shielding part with the front shape of the piezoelectric layer, several fitting parts are continuous in the spatial structure and cover the sidewall of the piezoelectric layer. This will not cause interference in the spatial structure, greatly reducing the transducer packaging size and facilitating the miniaturization and weight reduction of the transducer.

[0018] 4. Because the conductive matching layer has a spatially continuous structure, it can cover the slits between the transducer elements, forming an air gap structure between the elements, which improves the vibration efficiency of the piezoelectric elements and enhances the acoustic performance of the transducer. Attached Figure Description

[0019] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of this utility model.

[0020] Figure 1 This is a cross-sectional view of an ultrasonic transducer;

[0021] Figure 2 This is a side view of an ultrasonic transducer;

[0022] Figure 3 This is an installation diagram for an ultrasonic transducer;

[0023] Figure 4 This is a structural diagram of the conductive matching layer.

[0024] Explanation of icon numbers:

[0025] Conductive matching layer 1, first shielding part 11, second shielding part 12, first bonding block 121, second bonding block 122, first part 1221, second part 1222, first gap 123, second gap 124, piezoelectric layer 2, slit 21, backing layer 3. Detailed Implementation

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the specific implementation methods of this utility model will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0027] To keep the drawings concise, each figure only schematically shows the parts relevant to the utility model, and these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, only one of the components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0028] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this utility model. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

[0031] refer to Figures 1 to 3 This utility model provides an ultrasonic transducer, including a conductive matching layer 1, a piezoelectric layer 2 and a backing layer 3. The conductive matching layer 1 covers the front end of the piezoelectric layer 2 in all directions. The conductive matching layer 1 is adapted to be grounded and conduction so as to direct the interference signals on the front side and sidewall of the piezoelectric layer 2 to the ground. The backing layer 3 is disposed on the rear side of the piezoelectric layer 2.

[0032] In this embodiment, the conductive matching layer 1 covers the front end of the piezoelectric layer 2 in all directions. The conductive matching layer 1 is suitable for grounding and conduction. The conductive matching layer 1 can direct electromagnetic interference signals on the front side and sidewall of the piezoelectric layer 2 to the ground, thereby improving the stability and reliability of the signal. At this time, the conductive matching layer 1 is grounded and conduction to achieve the shielding function. There is no need to set up an additional shielding layer. While ensuring good acoustic performance, it plays a good role in anti-interference and shielding.

[0033] Specifically, in this application, a conductive matching layer 1 is disposed on top of the piezoelectric layer 2, covering the top surface and surrounding edges of the piezoelectric layer 2. The conductive matching layer 1, by grounding, guides induced charges or interference signals to ground, thereby shielding against electromagnetic interference. By grounding the conductive matching layer 1, this application can form a low-impedance path, guiding external electromagnetic interference signals to ground, thus effectively shielding these interferences. The conductivity of the conductive matching layer 1 can be achieved either by its own conductivity or by adding conductive materials to one and / or both sides of the conductive matching layer 1. The piezoelectric layer 2 includes pure piezoelectric materials, such as piezoelectric single crystals and piezoelectric ceramics, as well as piezoelectric composite materials prepared using piezoelectric single crystals and piezoelectric ceramics.

[0034] In one embodiment, the conductive matching layer 1 is formed by a composite of conductive filler (such as carbon black, metal powder, etc.) and a flexible polymer (such as polyimide). The conductive matching layer 1 itself is suitable for conducting and connecting the shielding ground and / or the signal ground. In this case, the conductivity of the conductive matching layer 1 mainly depends on the conductive network formed by the conductive filler in the flexible polymer matrix. According to percolation theory, when the content of conductive filler reaches a certain threshold, the conductivity of the conductive matching layer 1 will be significantly improved. The flexible polymer can maintain good acoustic matching performance, while the conductive filler imparts conductivity to the material, enabling it to be used for electrodes or signal transmission, and can conduct interference signals to the shielding ground and / or the signal ground. Therefore, this conductive matching layer 1 can not only serve as an acoustic matching layer, but also for signal transmission or electromagnetic shielding, achieving multi-functional integration. Moreover, the flexible polymer provides good mechanical properties and processability, making it suitable for applications requiring flexibility and bendability.

[0035] In another embodiment, the top and / or bottom surfaces of the conductive matching layer 1 are plated with a conductive layer, and the conductive matching layer 1 is adapted to conduct a connection between the shielding ground and / or the signal ground through the conductive layer. In this case, the acoustic matching layer is the main part of the conductive matching layer 1, typically made of a flexible polymer or composite material, and its acoustic characteristics (such as acoustic impedance) are optimized to match the acoustic requirements of the ultrasonic transducer. The acoustic matching layer reduces sound wave reflection between the transducer and the target medium by optimizing the acoustic impedance, thereby improving acoustic energy transmission efficiency. The conductive layer is plated on the top and / or bottom surfaces of the acoustic matching layer, and is typically made of metal (such as copper, silver) or a transparent conductive material (such as ITO). The conductive layer can be formed by sputtering, electroplating, evaporation, etc.; the conductive layer typically consists of a base layer and a top layer. The base layer is typically made of nickel, chromium, or a nickel-chromium alloy, with a thickness of 0.01-1 micrometer, and the top layer is typically made of a metal such as gold, silver, titanium, or copper, with a thickness of 0.05-5.0 micrometers. The primary function of the conductive layer is to provide an electrical path for connecting the shielding ground and / or signal ground, thus achieving electromagnetic shielding and signal transmission. The presence of the conductive layer does not significantly affect acoustic performance because its thickness is typically very thin (micrometer-level), and its impact on sound wave propagation is negligible. Furthermore, the conductive layer can be designed as a thin film, a mesh, or a strip structure, depending on the application requirements. For example, a thin film structure can provide uniform conductivity, while a mesh structure can reduce the impact on sound wave propagation.

[0036] It is worth noting that the conductive matching layer 1 is connected to the shielding ground and / or signal ground via a single-ended grounding, which is a common grounding method for ultrasonic transducers. However, the grounding conduction form of the conductive matching layer 1 is diverse, including but not limited to single-ended grounding; it can also be multi-point grounding, a common ground plane, etc. Multi-point grounding means that the conductive matching layer 1 can be grounded through multiple points. In wearable ultrasonic devices, liquid metal electrodes are used to form a stretchable shielding layer and are connected to the ground through vertical interconnection. A common ground plane refers to a design that uses a common ground plane, where the conductive matching layer 1 is connected to a dedicated grounding layer through a conductive layer, which covers the bottom or inner layer of the transducer.

[0037] Furthermore, the conductive matching layer 1 includes a first shielding portion 11 and a second shielding portion 12. The first shielding portion 11 is disposed on the front side of the piezoelectric layer 2 and is adapted to match the shape of the front side of the piezoelectric layer 2. The second shielding portion 12 is adapted to cover the periphery of the front end of the piezoelectric layer 2, so that the first shielding portion 11 and the second shielding portion 12 can wrap around the front end of the piezoelectric layer 2.

[0038] In this embodiment, the first shielding part 11 and the second shielding part 12 can cover the front end of the piezoelectric layer 2 in all directions. That is, the conductive matching layer 1 wraps the top surface (sound wave radiation surface) and side surface of the transducer in all directions of 360 degrees, which plays the role of shielding external interference and reducing external radiation interference. This not only optimizes the acoustic and electrical performance, but also improves the stability and detection accuracy of the transducer.

[0039] Specifically, the first shielding part 11 is attached to the front side of the piezoelectric layer 2, and the second shielding part 12 is attached to the four sides of the piezoelectric layer 2. The conductive matching layer 1 can absorb the ultrasonic waves emitted from the top and side surfaces of the piezoelectric layer 2, reducing the interference of back reflection waves on front reflection waves, thereby improving the accuracy of the signal and the imaging quality. The acoustic characteristics (such as acoustic impedance) of the conductive matching layer 1 can optimize the acoustic transition between the piezoelectric layer 2 and the target medium, improving the transmittance of acoustic energy and the sensitivity of the transducer. The conductive matching layer 1 can realize the solderless extraction of electrical signals, avoiding the contact problems and labor costs that may occur in traditional welding processes.

[0040] Further, refer to Figure 3 and Figure 4 The second shielding part 12 includes several bonding parts, which are arranged sequentially at intervals around the edge of the first shielding part 11. During the bonding process between the first shielding part 11 and the front side of the piezoelectric layer 2, the several bonding parts are adapted to come close to each other and form a tight connection.

[0041] In this embodiment, during the process of the first shielding part 11 fitting with the front shape of the piezoelectric layer 2, several fitting parts are continuous in the spatial structure and cover the sidewall of the piezoelectric layer 2. This does not cause interference in the spatial structure, greatly reducing the transducer packaging size and facilitating the miniaturization and lightweighting of the transducer.

[0042] Specifically, the bonding portion includes a plurality of first bonding blocks 121 and at least one second bonding block 122. The plurality of first bonding blocks 121 are spaced apart on the two long sides of the piezoelectric layer 2, and a first gap is provided between adjacent first bonding blocks 121. The second bonding blocks 122 are provided on the two short sides of the piezoelectric layer 2, and a second gap is provided between the second bonding blocks 122 and the first bonding blocks 121. The two sides of the second bonding block 122 are adapted to be tightly connected to the first bonding blocks 121. At this time, the first bonding blocks 121 and the second bonding blocks 122 in the long and short sides of the conductive matching layer 1 are bonded to the side of the transducer to form a transducer structure. It can be seen that the first bonding blocks 121 on the long side of the conductive matching layer 1 are tightly connected or overlapped in sequence to form a shielding protection structure on the long side of the transducer; the second bonding blocks 122 on the short side of the conductive matching layer 1 form a shielding protection structure on the short side of the transducer and are tightly connected or overlapped with the first bonding blocks 121 on the long side. The connection methods of adjacent first bonding blocks 121 and second bonding blocks 122 include both mutual abutment and interlocking of their ends and mutual overlap of their ends, as long as they can completely wrap around the front end of the piezoelectric layer 2. Without affecting sound wave propagation, 360-degree omnidirectional wrapping of the transducer's piezoelectric layer 2 greatly improves the transducer's EMC performance. The conductive layer of the bonding portion surrounding the transducer is connected to the cable shielding layer through shielding materials such as shielding copper foil. The conductive shielding layer can be machined into a specified shape and size by mechanical processing (e.g., laser, stamping), or manufactured by mold casting.

[0043] It is worth noting that the conductive matching layer 1 has good mechanical properties and processability, making it suitable for applications requiring flexibility and bendability. For example, the piezoelectric layer 2 has a convex array structure, the first bonding block 121 is an inverted trapezoid, and the second bonding block 122 is a fan shape. The second bonding block 122 includes a first part 1221 and a pair of second parts 1222. The first part 1221 is adapted to be bonded to the short side of the piezoelectric layer 2, and the second part 1222 is adapted to be bonded to the end of the long side of the piezoelectric layer 2 and tightly connected or overlapped with the first bonding block 121. In this embodiment, the second part 1222 of the second bonding block 122 is bonded to the end of the long side of the piezoelectric layer 2, so that the first bonding block 121 and the second bonding block 122 are tightly connected or overlapped, that is, the length of the bottom end of the second bonding block 122 is greater than the length of the long side of the piezoelectric layer. In a modified embodiment, the portion of the first bonding block 121 extending beyond the long side of the piezoelectric layer 2 can also be bonded to the short side of the piezoelectric layer 2, so that the first bonding block 121 and the second bonding block 122 are tightly connected or overlapped.

[0044] In another embodiment, the piezoelectric layer 2 has a concave array structure. In this case, the conductive matching layer 1 is not just a single layer; an additional layer of material needs to be added to the area of ​​the first bonding block 121 to ensure that the overlapping of the first bonding blocks 121 completely covers the long side of the transducer. The distribution of this layer is easily understood by those skilled in the art and will not be further described here. The first bonding block 121 is a trapezoid with an inverted triangular assembly gap, and the second bonding block 122 is fan-shaped. When fabricating a convex array transducer with an arc-shaped arrangement of array elements, the conductive shielding layer of this application can fit the transducer structure well without causing structural interference or abrupt changes, avoiding damage to the transducer signal output circuit, and also helping to reduce the transducer's package size.

[0045] Further, refer to Figure 1 The piezoelectric layer 2 is further provided with several array elements on the front side, and there are slits 21 between the array elements. The conductive matching layer 1 can wrap the piezoelectric layer 2 in all directions, so that an air gap structure is formed in the slits 21.

[0046] In this embodiment, since the conductive matching layer 1 has a spatially continuous structure, it can cover the slits 21 between each array element of the transducer, forming an air gap structure between each array element, which improves the vibration efficiency of the piezoelectric array element and enhances the acoustic performance of the transducer.

[0047] Specifically, the shielding layer proposed in this application has a continuous spatial structure. After covering the array elements, it prevents other materials (such as epoxy, silicone rubber, etc.) from entering the slits 21 between the array elements, avoiding acoustic mismatch problems caused by uneven material filling, ensuring a stable air gap structure between the array elements, improving the vibration efficiency of the piezoelectric element, and further enhancing the acoustic performance of the transducer. Moreover, the presence of the air gap structure can reduce acoustic coupling between adjacent array elements, thereby improving the vibration efficiency of the piezoelectric element. The encapsulation structure of the conductive matching layer 1 further optimizes the propagation path of sound waves and reduces energy loss by precisely controlling the gap between the array elements.

[0048] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of this utility model. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. An ultrasonic transducer, characterized by, It includes a conductive matching layer, a piezoelectric layer, and a backing layer. The conductive matching layer covers the front end of the piezoelectric layer in all directions and is adapted to be grounded to direct interference signals on the front and sidewalls of the piezoelectric layer to the ground. The backing layer is disposed on the rear side of the piezoelectric layer.

2. An ultrasonic transducer according to claim 1, characterized in that, The conductive matching layer is formed by a composite of conductive filler and flexible polymer, and the conductive matching layer itself is suitable for conducting and connecting the shielding ground and / or signal ground.

3. An ultrasonic transducer according to claim 1, characterized in that, The conductive matching layer includes an acoustic matching layer and a conductive layer. The top and / or bottom surfaces of the acoustic matching layer are plated with the conductive layer. The acoustic matching layer is adapted to conduct a connection between the shielding ground and / or the signal ground through the conductive layer.

4. An ultrasonic transducer according to any one of claims 1-3, characterized in that, The conductive matching layer includes a first shielding portion and a second shielding portion. The first shielding portion is disposed on the front side of the piezoelectric layer and is adapted to match the shape of the front side of the piezoelectric layer. The second shielding portion is adapted to cover the periphery of the front end of the piezoelectric layer, so that the first shielding portion and the second shielding portion can wrap around the front end of the piezoelectric layer.

5. An ultrasonic transducer according to claim 4, characterized in that, The second shielding part includes a plurality of bonding parts, which are arranged sequentially at intervals around the edge of the first shielding part. During the process of bonding the first shielding part with the front side of the piezoelectric layer, the plurality of bonding parts are adapted to come close to each other and form a tight connection.

6. An ultrasonic transducer according to claim 5, characterized in that, The bonding portion includes a plurality of first bonding blocks and at least one second bonding block. The plurality of first bonding blocks are spaced apart on the two long sides of the piezoelectric layer, and a first gap is provided between adjacent first bonding blocks. The second bonding blocks are disposed on the two short sides of the piezoelectric layer, and a second gap is provided between the second bonding blocks and the first bonding blocks. The two sides of the second bonding block are adapted to be tightly connected to the first bonding blocks.

7. An ultrasonic transducer according to claim 6, characterized in that, The piezoelectric layer has a convex array structure. The first bonding block is inverted trapezoidal and the second bonding block is fan-shaped. The second bonding block includes a first part and a pair of second parts. The first part is adapted to be bonded to the short side of the piezoelectric layer, and the second part is adapted to be bonded to the end of the long side of the piezoelectric layer and tightly connected to the first bonding block.

8. An ultrasonic transducer according to claim 1, characterized in that, The piezoelectric layer is further provided with a number of array elements on its front side, and there are slits between the array elements. The conductive matching layer can completely wrap the piezoelectric layer, so that an air gap structure is formed in the slits.

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