Ultrasonic transducers, ultrasonic fingerprint modules and electronic devices

Abstract

This application provides an ultrasonic transducer, an ultrasonic fingerprint module, and an electronic device. In the ultrasonic transducer, the excitation electrode includes at least one set of sub-excitation electrode groups, each set of sub-excitation electrode groups including multiple sub-excitation electrodes arranged along a first direction. The pads include at least one set of sub-pad groups corresponding to the at least one set of sub-excitation electrode groups, each set of sub-pad groups including multiple sub-pads arranged along a second direction. For each set of sub-excitation electrode groups, the multiple sub-excitation electrodes are electrically connected to multiple sub-pads in the corresponding set of sub-pad groups, with different sub-excitation electrodes electrically connected to different sub-pads. In each set of sub-pad groups, along the second direction, the first spacing between any two adjacent sub-pads is smaller than the width of each sub-pad in the second direction, and each set of sub-pad groups can be used for electrical connection to a single gold finger in an external circuit structure.

Description

Technical Field

[0001] This application relates to the field of ultrasonic transducer technology, and more particularly to an ultrasonic transducer, an ultrasonic fingerprint module, and an electronic device. Background Technology

[0002] Ultrasonic transducers utilize the mechatronic-electroelectric conversion properties of piezoelectric materials. On one hand, they can be excited by a voltage output from a driving circuit to emit ultrasonic signals; on the other hand, they convert reflected ultrasonic signals back from the outside into electrical signals, thereby acquiring information about the external sensing surface. They can be widely used in fields including, but not limited to, biometric identification (for example, an example application could be an ultrasonic fingerprint module that can acquire fingerprint images for fingerprint recognition). However, the reliability of ultrasonic transducers in related technologies still needs improvement. Utility Model Content

[0003] This application provides an ultrasonic transducer, an ultrasonic fingerprint module, and an electronic device.

[0004] According to a first aspect of the embodiments of this application, an ultrasonic transducer is provided, comprising: a substrate, a bottom electrode, a piezoelectric layer, a top electrode, an excitation electrode, and a pad;

[0005] The bottom electrode is disposed on the substrate, the piezoelectric layer is located above the substrate and covers the bottom electrode, at least a portion of the top electrode is located above the piezoelectric layer, the excitation electrode is disposed on the substrate and has a gap with the bottom electrode, and the top electrode is electrically connected to the excitation electrode;

[0006] The excitation electrode includes at least one set of sub-excitation electrode groups, each set of sub-excitation electrode groups includes a plurality of sub-excitation electrodes arranged along a first direction, and the pad includes at least one set of sub-pad groups corresponding to the at least one set of sub-excitation electrode groups, each set of sub-pad groups includes a plurality of sub-pads arranged along a second direction.

[0007] For each sub-excitation electrode group, the multiple sub-excitation electrodes are electrically connected to the multiple sub-pads in the corresponding sub-pad group of the sub-excitation electrode group, and different sub-excitation electrodes are electrically connected to different sub-pads.

[0008] In each sub-pad group, along the second direction, the first spacing between every two adjacent sub-pads is smaller than the width of each sub-pad in the second direction, and each sub-pad group can be used for electrical connection with a single gold finger in an external circuit structure.

[0009] In some optional embodiments, the excitation electrode includes at least two sets of sub-excitation electrode sets, and the pad includes at least two sets of sub-pad sets corresponding to the at least two sets of sub-excitation electrode sets;

[0010] In the second direction, the second spacing between each pair of adjacent sub-pad groups is greater than the first spacing between each pair of adjacent sub-pads in each sub-pad group.

[0011] In some alternative embodiments, the excitation electrode includes two sets of sub-excitation electrode sets, and the pads include two sets of sub-pad sets corresponding to the two sets of sub-excitation electrode sets.

[0012] In some alternative embodiments, the minimum circumscribed rectangles of at least two sets of sub-pads have equal widths along the second direction.

[0013] In some alternative embodiments, the first spacing ranges from 1µm to 10µm.

[0014] In some optional embodiments, the ultrasonic transducer also satisfies at least one of the following conditions:

[0015] At least one set of sub-excitation electrode groups includes two sub-excitation electrodes, and the sub-pad group corresponding to the set of sub-excitation electrode groups includes two sub-pads;

[0016] The number of sub-pads in each sub-pad group is the same, and the number of sub-excitation electrodes in each sub-excitation electrode group is the same; in at least one sub-pad group, the width of each sub-pad along the second direction is equal.

[0017] The pad also includes at least one target pad that is not electrically connected to the excitation electrode, wherein the width of the minimum circumscribed rectangle of the sub-pad group along the second direction is equal to the width of the target pad along the second direction, and / or the length of the sub-pad in the sub-pad group is equal to the length of the target pad.

[0018] In some alternative embodiments, the top electrode covers a portion of the excitation electrode to form an electrical connection with the excitation electrode;

[0019] Among the at least two sets of sub-excitation electrode groups, there are at least two sets of target sub-excitation electrode groups, wherein at least two sub-excitation electrodes in the target sub-excitation electrode groups have different widths in the first direction.

[0020] In some optional embodiments, among the at least two sets of sub-excitation electrode groups, there are two sets of target sub-excitation electrode groups, and the two sets of target sub-excitation electrode groups are respectively: a first set of sub-excitation electrode groups along the first direction, and a last set of sub-excitation electrode groups; wherein,

[0021] In the first group of sub-excitation electrode groups, the width of the first sub-excitation electrode along the first direction is greater than the width of the other sub-excitation electrodes; and in the last group of sub-excitation electrode groups, the width of the last sub-excitation electrode along the first direction is greater than the width of the other sub-excitation electrodes.

[0022] According to a second aspect of the embodiments of this application, an ultrasonic fingerprint module is provided, including: the ultrasonic transducer provided in the first aspect above.

[0023] According to a third aspect of the embodiments of this application, an electronic device is provided, including: the ultrasonic transducer provided in the first aspect above, or the ultrasonic fingerprint module provided in the second aspect above.

[0024] The ultrasonic transducer in this embodiment of the application has a top electrode electrically connected to an excitation electrode. The excitation electrode includes at least one set of sub-excitation electrode groups, each set of sub-excitation electrode groups including multiple sub-excitation electrodes arranged along a first direction. The pads include at least one set of sub-pad groups corresponding to the at least one set of sub-excitation electrode groups, each set of sub-pad groups including multiple sub-pads arranged along a second direction. For each set of sub-excitation electrode groups, the multiple sub-excitation electrodes are electrically connected to multiple sub-pads in the corresponding set of sub-pad groups. Different sub-excitation electrodes are electrically connected to different sub-pads. In each set of sub-pad groups, along the second direction, the first spacing between each pair of adjacent sub-pads is smaller than the width of each sub-pad in the second direction. Furthermore, each set of sub-pad groups can be used to electrically connect to a single gold finger in an external circuit structure.Therefore, on the one hand, the ultrasonic transducer can electrically connect multiple sub-excitation electrodes in at least one set of sub-excitation electrode groups to multiple sub-excitation pads in at least one set of sub-excitation electrode groups, thereby forming multiple electrical connection points between the excitation electrodes and the top electrode. This improves the reliability of the electrical connection between the excitation electrodes and the top electrode, reducing the risk of poor contact. Even if one sub-excitation electrode has poor contact with the top electrode, it does not affect the electrical connection status of other sub-excitation electrodes with the top electrode. Thus, during the use of the ultrasonic transducer, the pads can transmit signals to the top electrode more stably through the excitation electrodes, which is beneficial to improving the reliability of the ultrasonic transducer and its performance stability. On the other hand, since multiple sub-excitation pads in at least one set of sub-excitation electrode groups are electrically connected to multiple sub-excitation electrodes in at least one set of sub-excitation electrode groups in this embodiment, multiple independent electrical paths between multiple sub-excitation pads and multiple sub-excitation electrodes can be realized. During the testing phase of the ultrasonic transducer, multiple independent electrical paths can be used to more flexibly and conveniently implement... The current testing is to better ensure the reliability of the ultrasonic transducer during use. Furthermore, in the embodiments of this application, the first spacing between each pair of adjacent sub-pads along the second direction is smaller than the width of each sub-pad in the second direction. Each sub-pad group can be used for electrical connection with a single gold finger in an external circuit structure. Therefore, for the electrical connection of a single gold finger, it increases the number of sub-pads to increase the number of electrical connection points, which is beneficial to improving the reliability of the electrical connection between the pads and the single gold finger. This reduces the risk of poor contact between them. Even if one sub-pad has poor contact with the gold finger, it does not affect the electrical connection status of other sub-pads with the gold finger, thus improving the reliability of the electrical connection. In addition, the small spacing between the sub-pads in each sub-pad group can maximize the contact area with the gold finger, further improving the reliability of the electrical connection. Moreover, each sub-pad group can be adapted to the size and space occupied by the electrical connection of a single gold finger as much as possible, which helps to reduce the design difficulty of the ultrasonic transducer. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0026] Figure 1 A schematic diagram of an example ultrasonic transducer of this application is shown.

[0027] Figure 2 It shows Figure 1 A schematic diagram of an ultrasonic transducer as shown in the example, from another perspective.

[0028] Figure 3A It shows Figure 1 The example shows a schematic diagram of the electrical connection between an ultrasonic transducer and gold fingers on a circuit board.

[0029] Figure 3B It shows Figure 1 Another schematic diagram illustrating the electrical connection between the ultrasonic transducer and the gold fingers in the circuit board.

[0030] Figure 4 It shows Figure 1 A partial schematic diagram of two sets of sub-pads of an ultrasonic transducer as shown in the example.

[0031] Figure 5 It shows Figure 1 A partial schematic diagram of the excitation electrode of an ultrasonic transducer as shown in the example.

[0032] Figure 6 A simplified schematic diagram of oxide layer electrical breakdown is shown when the excitation electrode includes two sub-excitation electrodes and the pad includes two sub-pads.

[0033] Figure 7 A simplified schematic diagram of oxide layer electrical breakdown is shown when the excitation electrode includes four sub-excitation electrodes and the pad includes four sub-pads.

[0034] Figure 8 A schematic block diagram of an example ultrasonic fingerprint module of this application is shown.

[0035] Figure 9A A schematic block diagram of an example electronic device according to this application is shown.

[0036] Figure 9B A schematic block diagram of another example of an electronic device in this application is shown.

[0037] Explanation of reference numerals in the attached figures:

[0038] 100, Ultrasonic transducer; 10, Substrate; 20, Bottom electrode; 30, Piezoelectric layer; 40, Top electrode; 50, Excitation electrode; 510, Sub-excitation electrode group; 51, Sub-excitation electrode; 60, Pad; 61, Sub-pad; 610, Sub-pad group; 62, Target pad; 70, Trace; 200, Ultrasonic fingerprint module; 210, Circuit board; 220, Gold finger; 230, Conductive adhesive layer; 300, Electronic device; X, Width direction of the substrate; Y, Length direction of the substrate; Z, Thickness direction of the substrate; F1, First direction; F2, Second direction. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0040] Ultrasonic transducers utilize the mechatronic-electroelectric conversion properties of piezoelectric materials. On one hand, they can be excited by a voltage output from a driving circuit to emit ultrasonic signals; on the other hand, they convert reflected ultrasonic signals back from the outside into electrical signals, thereby acquiring information about the external sensing surface. They can be widely used in fields including, but not limited to, biometric identification (for example, an example application could be an ultrasonic fingerprint module that can acquire fingerprint images for fingerprint recognition). However, the reliability of ultrasonic transducers in related technologies still needs improvement.

[0041] According to a first aspect of the embodiments of this application, an ultrasonic transducer 100 is provided. (Refer to...) Figure 1 and Figure 2 As shown, the ultrasonic transducer 100 may include: a substrate 10, a bottom electrode 20, a piezoelectric layer 30, a top electrode 40, an excitation electrode 50, and a pad 60. The bottom electrode 20 is disposed on the substrate 10, the piezoelectric layer 30 is located above the substrate 10 and covers the bottom electrode 20, at least a portion of the top electrode 40 is located above the piezoelectric layer 30, the excitation electrode 50 is disposed on the substrate 10 and has a gap from the bottom electrode 20, and the top electrode 40 and the excitation electrode 50 are electrically connected. The excitation electrode 50 includes at least one set of sub-excitation electrode groups 510, each set of sub-excitation electrode groups 510 including a plurality of sub-excitation electrodes 51 arranged along a first direction. The pad 60 includes at least one set of sub-pad groups 610 corresponding to the at least one set of sub-excitation electrode groups 510, each set of sub-pad groups 610 including a plurality of sub-pads 61 arranged along a second direction. For the plurality of sub-excitation electrodes 51 in each set of sub-excitation electrode groups 510, the plurality of sub-excitation electrodes 51 are electrically connected to the plurality of sub-pads 61 in the sub-pad group 610 corresponding to that set of sub-excitation electrode groups 510, and different sub-excitation electrodes 51 are electrically connected to different sub-pads 61. In each set of sub-pad groups 610, along the second direction, the first spacing d1 between each pair of adjacent sub-pads 61 is smaller than the width of each sub-pad 61 in the second direction (e.g., ...). Figure 2 In d), and each sub-pad group 610 can be used for electrical connection with a single gold finger in an external circuit structure.

[0042] Based on this, the ultrasonic transducer 100 in this embodiment can, on the one hand, be electrically connected to multiple sub-excitation electrodes 51 in at least one set of sub-excitation electrode groups 51 respectively through multiple sub-pads 61 in at least one set of sub-pad groups 610. This allows multiple sub-excitation electrodes 51 to form multiple electrical connection points with the top electrode 40, improving the reliability of the electrical connection between the excitation electrode 50 and the top electrode 40. This reduces the risk of poor contact between them; even if one sub-excitation electrode 51 has poor contact with the top electrode 40, it does not affect the electrical connection between other sub-excitation electrodes 51 and the top electrode 40. In the connected state, during the use phase of the ultrasonic transducer 100, the pads 60 can transmit signals more stably to the top electrode 40 through the excitation electrode 50, which is beneficial to improving the reliability of the ultrasonic transducer 100 and its performance stability. On the other hand, since in this embodiment, multiple sub-pads 61 in at least one set of sub-pad groups 610 are respectively electrically connected to multiple sub-excitation electrodes 51 in at least one set of sub-excitation electrode groups 510, multiple independent electrical paths can be realized between the multiple sub-pads 61 and the multiple sub-excitation electrodes 51. During the testing phase of the ultrasonic transducer 100, multiple... Independent electrical paths allow for more flexible and convenient testing, better ensuring the reliability of the ultrasonic transducer 100 during use. Furthermore, in this embodiment, the first distance d1 between any two adjacent sub-pads 61 along the second direction is smaller than the width of each sub-pad 61 in the second direction. Each sub-pad group 610 can be used for electrical connection to a single gold finger in an external circuit structure (e.g., a circuit board, such as an FPC circuit board). Therefore, for electrical connection to a single gold finger, it also increases the number of sub-pads 61 to increase the number of electrical connection points, which is beneficial for improving the connection between the pads 60 and the single gold finger. The reliability of the electrical connection between the fingers is improved, thereby reducing the risk of poor contact. Even if one sub-pad 61 has poor contact with the gold finger, it will not affect the electrical connection status of other sub-pads 61 with the gold finger, thus improving the reliability of the electrical connection. In addition, the spacing between the sub-pads 61 in each group of sub-pads 610 is small, which can ensure a larger contact area with the gold finger, further improving the reliability of the electrical connection. Moreover, each group of sub-pads 610 can be adapted to the size space occupied by the electrical connection of a single gold finger as much as possible, which helps to reduce the design difficulty of the ultrasonic transducer 100.

[0043] The ultrasonic transducer 100 in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0044] Optionally, the substrate 10 can be a silicon-based substrate. Alternatively, the substrate 10 can be other types of substrates, such as glass substrates, as long as the requirements are met.

[0045] Optionally, refer to Figure 1 As shown, a bottom electrode 20 is disposed on the substrate 10, and a piezoelectric layer 30 and a top electrode 40 are sequentially stacked on top of the bottom electrode 20. The top electrode 40 is electrically connected to the excitation electrode 50, and the excitation electrode 50 is electrically connected to the pad 60. Optionally, as shown... Figure 1 and Figure 2 As shown, the top electrode 40 can cover part of the excitation electrode 50 to form an electrical connection with the excitation electrode 50. This electrical connection method is relatively stable, and it is also simpler to manufacture because it eliminates the need for additional interconnection structures.

[0046] When the ultrasonic transducer 100 is in use, the excitation electrode 50 can obtain an excitation signal through the pad 60 (e.g., from an external circuit electrically connected to the pad 60) and apply the excitation signal to the top electrode 40. The excitation electrode 50 is disposed on the substrate 10, and there is a gap between it and the bottom electrode 20, which can prevent the signal applied to the top electrode 40 from interfering with the bottom electrode 20. Optionally, the pad 60 can serve as an input / output port of the ultrasonic transducer 100, which can electrically connect the ultrasonic transducer 100 to an external circuit structure (e.g., a circuit board 210, which can be a flexible printed circuit (FPC)). For example, the pad 60 can be electrically connected to the gold fingers 220 of the circuit board 210 through a conductive adhesive layer 230.

[0047] Optionally, the top electrode 40 can be used to apply an excitation signal, thereby creating an electric field between the top electrode 40 and the bottom electrode 20 (i.e., a voltage difference across the piezoelectric layer 30 in the thickness direction), which excites the piezoelectric layer 30 to emit an ultrasonic signal. The bottom electrode 20 can be used to receive the ultrasonic detection signal generated between the top electrode 40 and the bottom electrode 20 when the returned ultrasonic signal acts on the piezoelectric layer 30. The ultrasonic detection signal can be an electrical signal generated by the returned ultrasonic signal acting on the piezoelectric layer 30, and can be used to generate an image. Optionally, the excitation signal can include, but is not limited to, pulse signals, AC signals, etc.

[0048] Specifically, after an excitation signal is applied to the top electrode 40, an electric field is formed between it and the bottom electrode 20, creating a voltage difference across the two sides of the piezoelectric layer 30 in the thickness direction. This excites the piezoelectric layer 30 to vibrate and emit ultrasonic signals. In this process, the piezoelectric layer 30 converts the electrical signal into an ultrasonic signal (i.e., mechanical vibration) based on the piezoelectric effect. The bottom electrode 20 can receive the ultrasonic detection signal (electrical signal) obtained from the ultrasonic signal converted and returned by the piezoelectric layer 30. Optionally, when the ultrasonic transducer 100 is used in an ultrasonic fingerprint module, the ultrasonic detection signal can be used to acquire a fingerprint image.

[0049] Optionally, the piezoelectric layer 30 may include any piezoelectric material. For example, it may include, but is not limited to, at least one of PVDF (polyvinylidene difluoride), lead zirconate titanate, and lithium niobate. The PVDF material may include PVDF, PVDF copolymers, etc. Optionally, the bottom electrode 20, top electrode 40, excitation electrode 50, and pad 60 may all be metal structures.

[0050] It should be understood that the ultrasonic transducer 100 with the optional structure of bottom electrode 20, piezoelectric layer 30, top electrode 40, excitation electrode 50 and pad 60 provided on the substrate 10 described above can effectively enable the ultrasonic transducer 100 to be used for ultrasonic transduction and detection functions, so that the ultrasonic transducer 100 can be effectively applied.

[0051] Optionally, refer to Figure 1 and Figure 2 As shown, the excitation electrode 50 may include at least one group of sub-excitation electrode groups 510. Each group of sub-excitation electrode groups 510 may include a plurality of sub-excitation electrodes 51 arranged along a first direction. That is, the first direction can be the arrangement direction of the plurality of sub-excitation electrodes 51. Figure 2 and Figure 4 Examples of the first direction F1 are shown in both.

[0052] Optionally, refer to Figure 1 and Figure 2 As shown, the pad 60 may include at least one set of sub-pad groups 610 corresponding to at least one set of sub-excitation electrode groups 510, and each set of sub-pad groups 610 includes a plurality of sub-pads 61 arranged along a second direction. That is, the second direction can be the arrangement direction of the plurality of sub-pads 61. Figure 2 and Figure 4 Examples of the second direction F2 are shown in both.

[0053] In the embodiments of this application, the first direction F1 and the second direction F2 can be the same or different, and can be selected according to design needs.

[0054] For example, such as Figure 1 and Figure 2 The example shown can use the width direction of the substrate as X, the length direction of the substrate as Y, and the thickness direction of the substrate as Z. Alternatively, as... Figure 2 , Figure 4 , Figure 5 As shown, an example is illustrated where the first direction F1 and the second direction F2 are the same, and both are the same as the width direction X of the substrate. In other embodiments, the first direction F1 and the second direction F2 may also be the same as the width direction Y of the substrate. Of course, the above are merely examples, and this application does not impose any unique limitations.

[0055] In this embodiment, each sub-excitation electrode group 510 contains multiple sub-excitation electrodes 51, each of which is electrically connected to multiple sub-pads 61 in the corresponding sub-pad group 610. Different sub-excitation electrodes 51 are electrically connected to different sub-pads 61. The specific method of electrical connection is not limited herein. For example, ... Figure 2 , Figure 3B As shown, the multiple sub-excitation electrodes 51 can be electrically connected to multiple sub-pads 61 in the sub-pad group 610 corresponding to the group of sub-excitation electrodes 510 through multiple traces 70 (e.g., metal traces). Different sub-excitation electrodes 51 are electrically connected to different sub-pads 61 through different traces 70.

[0056] In the embodiments of this application, reference is made to Figure 2 , Figure 3B and Figure 4 As shown, in each group of sub-pads 610, along the second direction F1, the first spacing d1 between any two adjacent sub-pads 61 is smaller than the width of each sub-pad 61 in the second direction F2. It should be noted that the widths of each sub-pad 61 in the second direction F2 can be the same or different. Figure 4 The example shown illustrates that each sub-pad 61 has the same width in the second direction F2, and the width of each sub-pad 61 in the second direction F2 is d.

[0057] It should be noted that if each group of sub-pads 610 includes three or more sub-pads 61, the first spacing d1 between any two adjacent sub-pads 61 can be the same or different.

[0058] This application specifically defines the specific value of the first spacing d1. For example, in some optional embodiments, the range of the first spacing d1 is 1µm to 10µm.

[0059] It should be understood that the first spacing d1, within this selectable range, allows for a sufficiently small spacing between the sub-pads 61, maximizing the contact area with the gold fingers and further improving electrical connection reliability. Combined with... Figure 3A and Figure 3B As illustrated, especially when the sub-pad group 610 and the gold fingers 220 of the external circuit structure (such as the circuit board) are electrically connected through the conductive adhesive layer 230 (e.g., anisotropic conductive film (ACF conductive film)), since the first spacing d1 within this optional range is small enough, the gap area between adjacent sub-pads 21 has a smaller impact on the pressing of the conductive adhesive layer 230, thereby improving the electrical connection stability when electrically connected through the conductive adhesive layer 230.

[0060] For example, within the selectable range of the first spacing d1 mentioned above, the following can be selected: including but not limited to 1.0um, 1.5um, 2.0um, 2.5um, 3.0um, 3.5um, 4.0um, 4.5um, 5.0um, 5.5um, 6.0um, 6.5um, 7.0um, 7.5um, 8.0um, 8.5um, 9.0um, 9.5um, 10.0um, etc.

[0061] The number of sub-excitation electrode groups 510 and the corresponding number of sub-pad groups 610 are not specifically limited in the embodiments of this application. For example, there can be one or more. In some optional embodiments, refer to Figure 2 , Figure 3B and Figure 5 As shown, the excitation electrode 50 may include at least two sets of sub-excitation electrode sets 510; refer to Figure 2 , Figure 3B and Figure 4 As shown, the pad 60 may include at least two sets of sub-pad groups 610 corresponding to at least two sets of sub-excitation electrode groups 510. Referring to... Figure 4 As shown, along the second direction F2, the second spacing d2 between each pair of adjacent sub-pad groups is greater than the first spacing d1 between each pair of adjacent sub-pads 61 in each sub-pad group 610.

[0062] It should be understood that during the use of the ultrasonic transducer 100, the signals that the pads 60 and excitation electrodes 50 need to transmit to the top electrode 40 may include high-voltage excitation signals. Therefore, in some cases, the pads 60 need to be electrically connected to multiple gold fingers 220 that are shorted in an external circuit structure (such as a circuit board 210, for example, an FPC circuit board) to meet the transmission requirements of high-voltage excitation signals. Therefore, the ultrasonic transducer 100 in this application sets at least two sets of sub-excitation electrode groups 510 and corresponding at least two sets of sub-pad groups 610, and sets the second spacing d2 between each pair of adjacent sub-pad groups 610 to be large (i.e., greater than the first spacing d1), so as to meet the requirements of electrical connection with multiple gold fingers 220. This allows the pads 60 and excitation electrodes 50 to transmit high-voltage excitation signals more reliably, ensuring that the top electrode 40 can be reliably excited, thereby improving the reliability of the ultrasonic transducer 100.

[0063] In some optional embodiments, the second spacing d2 can be greater than 0.4 mm. Such a second spacing d2 can better ensure the quality of electrical connection with the multiple gold fingers 220 and improve circuit reliability.

[0064] Optionally, during the use of the ultrasonic transducer 100, multiple sub-pad groups 610 can be electrically connected to multiple shorted gold fingers 220 of an external circuit structure (such as a circuit board 210, for example, an FPC circuit board) through a conductive adhesive layer 230 (such as an ACF conductive film). Each sub-pad 61 in the multiple sub-pad groups 610 can be shorted through the multiple shorted gold fingers 220. This facilitates the transmission of the same excitation signal to the top electrode 40 through multiple sub-pads 61 and multiple sub-excitation electrodes 51.

[0065] In some alternative embodiments, refer to Figure 2 , Figure 3B , Figure 4 and Figure 5 As shown, the excitation electrode 50 may include two sets of sub-excitation electrode groups 510, and the pad 60 may include two sets of sub-pad groups 610 corresponding to the two sets of sub-excitation electrode groups 510.

[0066] It should be understood that the ultrasonic transducer 100 in this application, by setting two sets of sub-excitation electrode groups 510 and corresponding two sets of sub-pad groups 610, can, on the one hand, facilitate the electrical connection with the two gold fingers 220, thereby enabling the pads 60 and excitation electrodes 50 to transmit higher voltage excitation signals more reliably, ensuring that the top electrode 40 can be applied a relatively reliable excitation signal, thus improving the reliability of the ultrasonic transducer 100; on the other hand, by using two sets of sub-excitation electrode groups 510 and two sets of sub-pad groups 610, while ensuring reliable transmission of excitation signals, the space occupied by the structure used for excitation signal transmission is not excessive, which is beneficial to improving the space utilization of the ultrasonic transducer 100. In addition, such a structure is also easier to manufacture.

[0067] In this embodiment, the number of sub-excitation electrodes 51 in each sub-excitation electrode group 510 can be the same or different, and can be selected as needed. The number of sub-pads 61 in each sub-pad group 610 can be the same or different, and can be selected as needed. In some optional embodiments, refer to... Figure 2 , Figure 3B , Figure 4 and Figure 5 As shown, the number of sub-pads 61 in each group of sub-pads 610 is the same, and the number of sub-excitation electrodes 51 in each group of sub-excitation electrode groups 510 is the same.

[0068] It should be understood that through such an optional structure, the top electrode 40 can form the same number of electrical connection points with each sub-excitation electrode group 510, each sub-excitation electrode group 510 can correspondingly form the same number of independent electrical paths with each sub-pad group 610, and each sub-pad group 610 can also form the same number of electrical connection points when electrically connected to the gold finger 220, thereby improving the uniformity of signal transmission.

[0069] In this embodiment, the specific number of sub-excitation electrodes 51 in the sub-excitation electrode group 510 can be selected as needed, for example, it can be 2, 3, or more. Similarly, the specific number of sub-pads 61 in the sub-pad group 610 can also be selected as needed, for example, it can be 2, 3, or more.

[0070] In some alternative embodiments, refer to Figure 2 , Figure 3B , Figure 4 and Figure 5 As shown, at least one set of sub-excitation electrode groups 510 includes two sub-excitation electrodes 51, and the sub-pad group 610 corresponding to the set of sub-excitation electrode groups 510 includes two sub-pads 61.

[0071] It should be understood that by setting up a sub-excitation electrode group 510 including two sub-excitation electrodes 51 and a sub-pad group 610 including two sub-pads 61, the spacing area between the sub-pads 61 in each sub-pad group 610 is reduced, thereby better ensuring the contact area of ​​the electrical connection between each sub-pad group 610 and the gold finger 220. Furthermore, this structure is easier to manufacture. Especially when the sub-pad group 610 and the gold finger 220 are electrically connected through a conductive adhesive layer 230 (such as an ACF conductive film), the smaller spacing area has less impact on the pressing of the conductive adhesive layer 230, thus improving the electrical connection stability when electrically connected through the conductive adhesive layer 230.

[0072] In some alternative embodiments, refer to Figure 2 , Figure 3B , Figure 4 and Figure 5 As shown, each sub-excitation electrode group 510 may include two sub-excitation electrodes 51, and the sub-pad group 610 corresponding to each sub-excitation electrode group 510 (that is, each sub-pad group 610) includes two sub-pads 61.

[0073] This can better ensure the contact area of ​​the electrical connection between each group of sub-pads 610 and the gold finger 220, and when the sub-pads 610 and the gold finger 220 are electrically connected through the conductive adhesive layer 230 (such as ACF conductive film), it is beneficial to improve the electrical connection stability when electrically connected through the conductive adhesive layer 230.

[0074] For example, such as Figure 2 , Figure 3B and Figure 4 As shown, the pad 60 includes two sets of sub-pad groups 610, each set of sub-pad groups 610 including two sub-pads 61. One set of sub-pad groups 610 includes sub-pads 61A and 61B, and the other set of sub-pad groups 610 includes sub-pads 61C and 61D. In each set of sub-pad groups 610, the first spacing d1 between the two sub-pads 61 is less than the width d of each sub-pad in the second direction F2.

[0075] For example, such as Figure 2 , Figure 3B and Figure 4 As shown, the pad 60 includes two sets of sub-pad groups 610, each set of sub-pad groups 610 including two sub-pads 61. One set of sub-pad groups 610 includes sub-pads 61A and 61B, and the other set of sub-pad groups 610 includes sub-pads 61C and 61D. In each set of sub-pad groups 610, the first spacing d1 between the two sub-pads 61 is less than the width d of each sub-pad in the second direction F2. The first spacing d1 in each of the two sets of sub-pad groups 610 is equal. The second spacing d2 between adjacent sets of sub-pad groups 610 is greater than the first spacing d1 between adjacent sub-pads 61 in each set of sub-pad groups 610.

[0076] For example, such as Figure 2 , Figure 3B and Figure 5 As shown, the pad 60 includes two sets of sub-excitation electrode groups 510, each set of sub-excitation electrode groups 510 including two sub-excitation electrodes 51. One set of sub-excitation electrode groups 510 includes sub-excitation electrodes 51A and 51B, and the other set of sub-excitation electrode groups 510 includes sub-excitation electrodes 51C and 51D.

[0077] Optionally, such as Figure 2 , Figure 3B and Figure 4 As shown, in at least one group of sub-pads 610, the width of each sub-pad 61 along the second direction F2 is equal. When each group of sub-pads 610 includes two sub-pads 61, each sub-pad 61 is set to have the same width (e.g., ...). Figure 2 In step d), when the sub-pad group 610 is electrically connected to the gold finger 220, the gold finger 220 can be uniformly pressed onto the two sub-pads 61 to achieve electrical connection, achieving essentially the same contact area, which is beneficial to improving electrical connection performance. Optionally, in each sub-pad group 610, the width of each sub-pad 61 along the second direction F2 is equal.

[0078] Of course, in other embodiments, the widths of the individual sub-pads 61 in the single sub-pad group 610 along the second direction F2 may not be equal, as long as the requirements are met.

[0079] Optionally, the lengths of the sub-pads 61 in a single sub-pad group 610 can be equal or unequal, as long as the requirements are met. For example, if a sub-pad 61 can be rectangular, then its length can be the length of the sub-pad 61 along a direction perpendicular to the second direction F2. Figure 2 In the example shown, if the second direction F2 is the same as the width direction X of the base, then the other direction can be the same as the length direction Y of the base.

[0080] In some alternative embodiments, refer to Figure 4 As shown, the minimum circumscribed rectangles of at least two sets of sub-pad groups 610 have equal widths d3 along the second direction F2. Since multiple gold fingers 220 can usually be designed with the same width, the fact that the minimum circumscribed rectangles of at least two sets of sub-pad groups 610 in this application have equal widths d3 along the second direction F1 facilitates a more uniform electrical connection with multiple gold fingers 220 of the same width.

[0081] In some alternative embodiments, refer to Figure 2 , Figure 3B and Figure 4 As shown, the pad 60 may also include at least one target pad 62 that is not electrically connected to the excitation electrode 50, and the width d3 of the minimum circumscribed rectangle of the sub-pad group 610 along the second direction F2 is equal to the width of the target pad 62 along the second direction F2.

[0082] In this embodiment, the sub-pad group 610 can be equivalent to a single pad that has been "divided into multiple" sub-pads, while the target pad 62 can be a single pad that has not been "divided into multiple" sub-pads. In the above optional structure in this embodiment, the width d3 of the minimum bounding rectangle of the sub-pad group 610 along the second direction F2 can be equal to the width of the target pad 62 along the second direction F2, so that the total width of the sub-pad group 610 is the same as the width of the ordinary target pad 62. Therefore, it avoids the sub-pad group 610 occupying more space on the substrate 10 in the second direction F2 after being divided into multiple sub-pads 61, thus more effectively adapting to the space occupied by a single gold finger 220 electrical connection, which helps to reduce the design difficulty of the ultrasonic transducer 100 and ensures the compatibility with the gold finger 220 electrical connection.

[0083] For example, in the above optional structure, the width d3 of the minimum circumscribed rectangle of the sub-pad group 610 along the second direction F2 is equal to the width of the target pad 62 along the second direction F2. This makes it easier to achieve a bonding effect between the sub-pad group 610 and the gold finger 220 when they are pressed together through the conductive adhesive layer 230 to achieve electrical connection. This effect is close to the bonding effect between the target pad 62 and the gold finger 220 through the conductive adhesive layer 230.

[0084] In other alternative embodiments, the width d3 of the minimum circumscribed rectangle of the sub-pad group 610 along the second direction F2 may not be equal to the width of the target pad 62 along the second direction F2, as long as the requirements are met.

[0085] In some alternative embodiments, refer to Figure 2 , Figure 3B As shown, the length of the sub-pad 61 in the sub-pad group 610 can be equal to the length of the target pad 62. This allows the total length of the sub-pad group 610 to be the same as the length of the ordinary target pad 62, thus avoiding the sub-pad group 610 occupying more space on the substrate 10 after being divided into multiple sub-pads 61. This allows for more effective adaptation to the space occupied by a typical single gold finger 220 electrical connection, reducing the design difficulty of the ultrasonic transducer 100 and ensuring compatibility with the gold finger 220 electrical connection.

[0086] For example, in the above optional structure, the length of the sub-pad 61 can be equal to the length of the target pad 62, which makes it easier to achieve a bonding effect when the sub-pad group 610 and the gold finger 220 are pressed together through the conductive adhesive layer 230 to achieve electrical connection, which is close to the bonding effect between the target pad 62 and the gold finger 220 through the conductive adhesive layer 230.

[0087] For example, if the target pad 62 can be rectangular, then the length here can be the length of the target pad 62 along another direction perpendicular to the second direction F2. Figure 2 In the example shown, if the second direction F2 is the same as the width direction X of the base, then the other direction can be the same as the length direction Y of the base.

[0088] In other alternative embodiments, the length of the sub-pad 61 may also be different from the length of the target pad 62, as long as the requirements are met.

[0089] In some alternative embodiments, refer to Figure 1 , Figure 2 , Figure 3A , Figure 3B , Figure 5As shown, the top electrode 40 can cover a portion of the excitation electrode 50 to form an electrical connection with the excitation electrode 50; see reference. Figure 2 , Figure 3B , Figure 5 As shown, among at least two sets of sub-excitation electrode groups 510, there are at least two sets of target sub-excitation electrode groups, wherein, in the target sub-excitation electrode group, at least two sub-excitation electrodes 51 have different widths in the first direction F1.

[0090] It should be understood that the top electrode 40 forms an electrical connection with the excitation electrode 50 by covering a portion of it. This electrical connection method is relatively stable, and it is also simpler to manufacture because it eliminates the need for additional interconnection structures. In addition, in the target sub-excitation electrode group, at least two sub-excitation electrodes 51 have different widths in the first direction F1, which also makes the fabrication of the sub-excitation electrodes 51 in the target sub-excitation electrode group more flexible to adapt to different needs.

[0091] It should be noted that at least two sets of sub-excitation electrode groups 510 can be flexibly constructed into a target sub-excitation electrode group as needed, and no specific restrictions are imposed in this application.

[0092] In some alternative embodiments, refer to Figure 2 , Figure 3B , Figure 5 As shown, in at least two sets of sub-excitation electrode groups 510, there are two sets of target sub-excitation electrode groups, and the two sets of target sub-excitation electrode groups are: a first set of sub-excitation electrode groups 510 along the first direction F1 and a last set of sub-excitation electrode groups 510; wherein, in the first set of sub-excitation electrode groups 510, the width of the first sub-excitation electrode 51 along the first direction F1 is greater than the width of the other sub-excitation electrodes 51; and, in the last set of sub-excitation electrode groups 510, the width of the last sub-excitation electrode 51 along the first direction F1 is greater than the width of the other sub-excitation electrodes 51.

[0093] For example, Figure 2 , Figure 3B , Figure 5 In the ultrasonic transducer 100 shown, the excitation electrode 50 may include two sets of sub-excitation electrode groups 510, and both sets of sub-excitation electrode groups 510 are target sub-excitation electrode groups. Each set of sub-excitation electrode groups 510 includes two sub-excitation electrodes 51. Then, as... Figure 2 , Figure 3B , Figure 5As shown, in the first group of sub-excitation electrode groups 510 along the first direction F1, the width W1 of the first sub-excitation electrode 51A along the first direction F1 is greater than the width W2 of the last sub-excitation electrode 51B along the first direction F1; in the second group of sub-excitation electrode groups 510 (that is, the last group of sub-excitation electrode groups 510) along the first direction F1, the width W4 of the last sub-excitation electrode 51D along the first direction F1 is greater than the width W3 of the first sub-excitation electrode 51C along the first direction F1.

[0094] It should be understood that when the ultrasonic transducer 100 includes an optional structure in which "the top electrode 40 forms an electrical connection with the excitation electrode 50 by covering a portion of the excitation electrode 50," then during the fabrication of the ultrasonic transducer 100, the portion of the top electrode 40 covering the excitation electrode 50 can be confined within the boundary of the excitation electrode 50 (e.g., it can be combined with...). Figure 2 , Figure 3A and Figure 5 understand).

[0095] In this application, the two sets of target sub-excitation electrode groups can be designed as a first set of sub-excitation electrode groups 510 and a last set of sub-excitation electrode groups 510 along the first direction F1. The width of the first sub-excitation electrode 51 along the first direction F1 in the first set of sub-excitation electrode groups 510 is greater than the width of the other sub-excitation electrodes 51. Similarly, the width of the last sub-excitation electrode 51 along the first direction F1 in the last set of sub-excitation electrode groups 510 is greater than the width of the other sub-excitation electrodes 51. This way, during the fabrication of the top electrode 40 (e.g., by printing with silver paste), if a dimensional deviation occurs in the portion covering the excitation electrode 50 along the first direction F1, it can be corrected by using the wider first sub-excitation electrode 51 (which can be combined with...). Figure 2 , Figure 3B , Figure 5 (understand sub-excitation electrode 51A in the middle), and the last sub-excitation electrode 51 (can be combined with) Figure 2 , Figure 3B , Figure 5 (Understanding the sub-excitation electrode 51D in the middle) to reduce the influence of the position deviation of the top electrode 40, thereby effectively preventing the top electrode 40 from exceeding the boundary of the excitation electrode 50. In addition, it can also make it easier for the top electrode 40 to cover each sub-excitation electrode 50 of the excitation electrode 50 more uniformly. For example, the coverage area can be close, thereby ensuring that the resistance of each sub-excitation electrode 51 is close, improving the consistency of the electrical connection performance between the top electrode 40 and each sub-excitation electrode 51, and improving the uniformity of signal transmission of each sub-excitation electrode 51.

[0096] Optionally, since there is an oxide layer between each sub-excitation electrode 51 of the excitation electrode 50 and the top electrode 40 in the ultrasonic transducer 100, electrical conduction can be achieved through electrical breakdown after connection. For example, Figure 6 A simplified schematic diagram of oxide layer electrical breakdown is shown when the excitation electrode includes two sub-excitation electrodes and the pad includes two sub-pads. Figure 6 It includes subgraph a and subgraph b, such as Figure 6 As shown in sub-figure a, after the two sub-pads 61 are connected to a power supply (taking 5V as an example), the oxide layer between the two sub-excitation electrodes 51 and the top electrode 40 can be equivalent to two capacitors; then as shown in the figure a, after the two sub-pads 61 are connected to a power supply (taking 5V as an example), the oxide layer between the two sub-excitation electrodes 51 and the top electrode 40 can be equivalent to two capacitors; then as shown Figure 6 As shown in sub-figure b, after the oxide layer undergoes electrical breakdown, it can be equivalent to two electrical connection sites. For example, Figure 7 A simplified schematic diagram of oxide layer electrical breakdown is shown when the excitation electrode includes four sub-excitation electrodes and the pad includes four sub-pads. (See diagram for reference.) Figure 7 As shown, after the four sub-pads 61 are connected to the power supply (taking 5V as an example), the oxide layer between the four sub-excitation electrodes 51 and the top electrode 40 can be equivalent to four capacitors. Similarly, after the oxide layer is electrically broken down, it can be equivalent to four electrical connection points.

[0097] Therefore, even if conduction is achieved through oxide layer electrical breakdown, when the ultrasonic transducer 100 in this embodiment is electrically connected to multiple sub-excitation electrodes 51 in at least one set of sub-excitation electrode groups 510 via multiple sub-pads 61 in at least one set of sub-pad groups 610, multiple electrical connection points can be formed between the multiple sub-excitation electrodes 51 and the top electrode 40. This improves the reliability of the electrical connection between the excitation electrode 50 and the top electrode 40, thereby reducing the risk of poor contact. Even if one sub-excitation electrode 51 has poor contact with the top electrode 40, it does not affect the electrical connection between the other sub-excitation electrodes 51 and the top electrode 40. Thus, during the use of the ultrasonic transducer 100, the pads 60 can transmit signals more stably to the top electrode 40 through the excitation electrode 50, which is beneficial to improving the reliability of the ultrasonic transducer 100 and its performance stability. It should be understood that... Figure 6 and Figure 7 The examples provided are merely for illustrative purposes and are not intended to limit the scope of the embodiments described in this application.

[0098] It is understood that the various optional embodiments described above can be selected according to actual needs. The descriptions of various aspects of the embodiments of this application are merely illustrative examples of some optional technical solutions of the embodiments of this application, and are not intended to limit the embodiments of this application in any way.

[0099] According to a second aspect of the embodiments of this application, in conjunction with Figure 8As shown, an ultrasonic fingerprint module 200 is provided, including an ultrasonic transducer 100 as provided in the first aspect.

[0100] Since the ultrasonic fingerprint module 200 of the second aspect includes the ultrasonic transducer 100 of the first aspect, it also has good reliability.

[0101] Optionally, refer to Figure 3A As shown in Figure 3A, in addition to illustrating the ultrasonic transducer 100, an exemplary structure of an ultrasonic fingerprint module 200 is also shown. As shown in Figure 3A, the ultrasonic fingerprint module 200 may include a circuit board 210, which is provided with gold fingers 220. The gold fingers 220 of the circuit board 210 are electrically connected to pads 60 through a conductive adhesive layer 230, and each individual gold finger 220 is electrically connected to a group of sub-pads 610 through the conductive adhesive layer 230.

[0102] Optionally, the circuit board 210 may be, but is not limited to, an FPC circuit board or a PCB circuit board. Optionally, the conductive adhesive layer 230 may be, but is not limited to, an ACF conductive film.

[0103] Optionally, refer to Figure 3B As shown, in the ultrasonic fingerprint module 200, the pads 60 of the ultrasonic transducer 100 may include multiple sets of sub-pad groups 610 (i.e., at least two sets). Each set of sub-pad groups 610 can be electrically connected to multiple gold fingers 220. These multiple gold fingers 220 can be shorted together, and the multiple sub-pad groups 610 can be shorted together through these multiple gold fingers 220. For example... Figure 3B As shown, this is an example of two sets of sub-pad groups 610 being electrically connected to two gold fingers 220 respectively.

[0104] According to the third aspect of the embodiments of this application, referring to Figure 9A , Figure 9B As shown, an electronic device 300 is provided, including: the ultrasonic transducer 100 provided in the first aspect above, or the ultrasonic fingerprint module 200 provided in the second aspect above.

[0105] In some alternative embodiments, the electronic device 300 also includes a screen, a back panel, and a side bezel.

[0106] Optionally, taking the electronic device 300 including an ultrasonic fingerprint module 200 as an example, the ultrasonic fingerprint module 200 can be attached to the lower surface of the screen, the inner side of the back panel, or the inner side of the side bezel. That is, the ultrasonic fingerprint module 200 can be an under-display ultrasonic fingerprint module, a rear ultrasonic fingerprint module, or a side ultrasonic fingerprint module of the electronic device 300. This enables under-display ultrasonic fingerprint recognition, rear ultrasonic fingerprint recognition, or side ultrasonic fingerprint recognition.

[0107] Optionally, the electronic device 300 can be any electronic device, including but not limited to mobile phones, computers, etc. It should be understood that the embodiments of this application do not limit the way the ultrasonic fingerprint module 200 is installed on the electronic device 300. As an example, taking a mobile phone as the electronic device 300 and including the ultrasonic fingerprint module 200, the ultrasonic fingerprint module 200 can be adhered to the underside of the mobile phone screen of the electronic device 300 through an adhesive layer to achieve under-display ultrasonic fingerprint recognition. It should be understood that in optional embodiments where the ultrasonic fingerprint module 200 is a rear ultrasonic fingerprint module or a side ultrasonic fingerprint module of the electronic device 300, the adhesive connection can also be achieved through an adhesive layer.

[0108] It should be understood that the above are merely illustrative applications and are not intended to limit the embodiments of this application.

[0109] The optional embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present application are not limited thereto. It should be noted that, for the convenience of explaining the embodiments of the present application, the various drawings of the embodiments of the present application are not necessarily drawn to scale, and are only used to facilitate the explanation of the technical solution, and are not intended to limit the embodiments of the present application in any way. Within the scope of the technical concept of the embodiments of the present application, various simple modifications can be made to the technical solutions of the embodiments of the present application. The various technical features included in the different embodiments of the present application can be combined and / or separated in any suitable manner. In order to avoid unnecessary repetition, the embodiments of the present application will not describe the various possible combinations separately. However, these simple modifications and combinations should also be regarded as the content disclosed in the embodiments of the present application, and all fall within the protection scope of the embodiments of the present application.

[0110] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". It should be noted that the concepts of "first", "second", etc., mentioned in the embodiments of this application are only used to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies. It should be noted that the modifications of "a" and "a plurality" mentioned in the embodiments of this application are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An ultrasonic transducer, characterized in that, include: Substrate, bottom electrode, piezoelectric layer, top electrode, excitation electrode, and pads; The bottom electrode is disposed on the substrate, the piezoelectric layer is located above the substrate and covers the bottom electrode, at least a portion of the top electrode is located above the piezoelectric layer, the excitation electrode is disposed on the substrate and has a gap with the bottom electrode, and the top electrode is electrically connected to the excitation electrode; The excitation electrode includes at least one set of sub-excitation electrode groups, each set of sub-excitation electrode groups includes a plurality of sub-excitation electrodes arranged along a first direction, and the pad includes at least one set of sub-pad groups corresponding to the at least one set of sub-excitation electrode groups, each set of sub-pad groups includes a plurality of sub-pads arranged along a second direction. For each sub-excitation electrode group, the multiple sub-excitation electrodes are electrically connected to the multiple sub-pads in the corresponding sub-pad group of the sub-excitation electrode group, and different sub-excitation electrodes are electrically connected to different sub-pads. In each sub-pad group, along the second direction, the first spacing between every two adjacent sub-pads is smaller than the width of each sub-pad in the second direction, and each sub-pad group can be used for electrical connection with a single gold finger in an external circuit structure.

2. The ultrasonic transducer according to claim 1, characterized in that, The excitation electrode includes at least two sets of sub-excitation electrode sets, and the pad includes at least two sets of sub-pad sets corresponding to the at least two sets of sub-excitation electrode sets. In the second direction, the second spacing between each pair of adjacent sub-pad groups is greater than the first spacing between each pair of adjacent sub-pads in each sub-pad group.

3. The ultrasonic transducer according to claim 2, characterized in that, The excitation electrode includes two sets of sub-excitation electrode groups, and the pad includes two sets of sub-pad groups corresponding to the two sets of sub-excitation electrode groups.

4. The ultrasonic transducer according to claim 2, characterized in that, The minimum bounding rectangles of at least two sets of sub-pads have equal widths along the second direction.

5. The ultrasonic transducer according to claim 1, characterized in that, The first spacing ranges from 1µm to 10µm.

6. The ultrasonic transducer according to any one of claims 1-5, characterized in that, The ultrasonic transducer also satisfies at least one of the following conditions: At least one set of sub-excitation electrode groups includes two sub-excitation electrodes, and the sub-pad group corresponding to the set of sub-excitation electrode groups includes two sub-pads; The number of sub-pads in each sub-pad group is the same, and the number of sub-excitation electrodes in each sub-excitation electrode group is the same; in at least one sub-pad group, the width of each sub-pad along the second direction is equal. The pad also includes at least one target pad that is not electrically connected to the excitation electrode, wherein the width of the minimum circumscribed rectangle of the sub-pad group along the second direction is equal to the width of the target pad along the second direction, and / or the length of the sub-pad in the sub-pad group is equal to the length of the target pad.

7. The ultrasonic transducer according to any one of claims 2-5, characterized in that, The top electrode covers a portion of the excitation electrode to form an electrical connection with the excitation electrode; Among the at least two sets of sub-excitation electrode groups, there are at least two sets of target sub-excitation electrode groups, wherein at least two sub-excitation electrodes in the target sub-excitation electrode groups have different widths in the first direction.

8. The ultrasonic transducer according to claim 6, characterized in that, Among the at least two sets of sub-excitation electrode groups, there are two sets of target sub-excitation electrode groups, and the two sets of target sub-excitation electrode groups are respectively: a first set of sub-excitation electrode groups along the first direction, and a last set of sub-excitation electrode groups; wherein, In the first group of sub-excitation electrode groups, the width of the first sub-excitation electrode along the first direction is greater than the width of the other sub-excitation electrodes; and in the last group of sub-excitation electrode groups, the width of the last sub-excitation electrode along the first direction is greater than the width of the other sub-excitation electrodes.

9. An ultrasonic fingerprint module, characterized in that, include: The ultrasonic transducer as described in any one of claims 1-8.

10. An electronic device, characterized in that, include: The ultrasonic transducer as described in any one of claims 1-8, or the ultrasonic fingerprint module as described in claim 9.

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