Ultrasonic sensor, fingerprint identification device and electronic device

Abstract

The utility model discloses an ultrasonic sensor, fingerprint identification device and electronic equipment, this ultrasonic sensor includes: substrate, piezoelectric transducer is set up on the substrate, first chip is set up on the substrate, and with piezoelectric transducer electric connection, the first chip includes one of emission chip, receiving chip and integrated chip, wherein the integrated chip integrates the circuit of emission chip and receiving chip. According to the ultrasonic sensor of the utility model embodiment, can shorten the transmission path between piezoelectric transducer and first chip, and be favorable to reduce the size of sensor.

Description

Technical Field

[0001] This utility model generally relates to the field of sensor technology. More specifically, this utility model relates to an ultrasonic sensor, a fingerprint recognition device, and an electronic device. Background Technology

[0002] In the field of ultrasonic sensors, existing technologies typically employ glass substrates to integrate piezoelectric transducers and thin-film transistor (TFT) circuits to construct ultrasonic sensing devices. The TFT circuits are connected to an application-specific integrated circuit (ASIC) chip via a flexible circuit board. The ASIC chip is used to control and drive the transmission of ultrasonic signals, and / or to control, receive, and process signals sensed by the piezoelectric transducer. For example... Figure 1 As shown, the ultrasonic sensing device 100 includes a glass substrate 110 and a flexible circuit board 120, wherein a piezoelectric transducer 111 and a TFT circuit 112 are disposed on the glass substrate 110, and an ASIC chip 121 is disposed on the flexible circuit board 120.

[0003] However, this technology has many limitations. On the one hand, because TFT manufacturing is a low-end process, the resulting TFT circuit area is relatively large, requiring a significant amount of space to be reserved on the glass substrate for the TFT circuit, which greatly limits the size of the piezoelectric transducer. For example, when the glass substrate size is 12mm × 10mm, the piezoelectric transducer size can only reach 8mm × 8mm. On the other hand, the long transmission distance between the ASIC chip and the piezoelectric transducer via the flexible printed circuit board 120 affects signal transmission. Therefore, existing ultrasonic sensing devices struggle to meet the demands of modern electronic devices for miniaturized, high-performance sensors.

[0004] In view of this, there is an urgent need to provide an ultrasonic sensor solution that can help to miniaturize ultrasonic sensors and improve their performance. Utility Model Content

[0005] In order to solve at least one or more of the technical problems mentioned above, this utility model proposes an ultrasonic sensor, fingerprint recognition device and electronic device solution in several aspects.

[0006] In a first aspect, the present invention provides an ultrasonic sensor, comprising: a substrate; a piezoelectric transducer disposed on the substrate; and a first chip disposed on the substrate and electrically connected to the piezoelectric transducer, wherein the first chip comprises one of a transmitting chip, a receiving chip, and an integrated chip, wherein the integrated chip integrates the circuitry of the transmitting chip and the receiving chip.

[0007] In some embodiments, the ultrasonic sensor further includes a second chip, which includes one of the transmitting chip and the receiving chip, and the first chip includes the other of the transmitting chip and the receiving chip; and at least one of the first chip and the second chip is disposed on a substrate on the side of the piezoelectric transducer.

[0008] In other embodiments, the first chip and the second chip are disposed on the same side of the substrate of the piezoelectric transducer, or on separate substrates on opposite sides of the piezoelectric transducer.

[0009] In other embodiments, the ultrasonic sensor further includes: a first connecting plate connected to the substrate; and a second chip disposed on the first connecting plate.

[0010] In some other embodiments, the first connecting plate includes a connecting portion and an extension portion, the connecting portion being connected to the substrate, the extension portion being connected to the connecting portion, and the second chip being disposed on the extension portion.

[0011] In some embodiments, the ratio of the area of ​​the piezoelectric transducer to the area of ​​the substrate surface is greater than 0.6.

[0012] In other embodiments, the piezoelectric transducer includes a lower electrode layer, a piezoelectric material layer, and an upper electrode layer, wherein the piezoelectric material layer is located between the lower electrode layer and the upper electrode layer, and the lower electrode layer is located between the substrate and the piezoelectric material layer; the ultrasonic sensor further includes a protective layer that covers the upper electrode layer and the substrate surface where the piezoelectric transducer is located, exposing a first connecting pad led out from the lower electrode layer and a second connecting pad led out from the upper electrode layer.

[0013] In some other embodiments, the exposed first connection pad is electrically connected to one of the transmitting chip and the receiving chip, and the exposed second connection pad is electrically connected to the other of the transmitting chip and the receiving chip; or the exposed first connection pad and the second connection pad are electrically connected to the integrated chip.

[0014] In some embodiments, the ultrasonic sensor further includes a second connection plate for connecting to an external system, the second connection plate being connected to the substrate, and the number of output connection pads on the substrate for connecting to the second connection plate being less than the number of the first connection pads and / or the number of the second connection pads.

[0015] In other embodiments, the lower electrode layer includes a plurality of parallel strip-shaped lower electrodes, wherein each lower electrode leads out a corresponding first connection pad; the upper electrode layer includes a plurality of parallel strip-shaped upper electrodes, wherein each upper electrode leads out a corresponding second connection pad; the plurality of lower electrodes of the lower electrode layer and the plurality of upper electrodes of the upper electrode layer are orthogonally arranged.

[0016] In some other embodiments, the width of each lower electrode is 30 μm to 150 μm; the physical distance between two adjacent lower electrodes is 50 μm to 200 μm, the physical distance being the distance from center to center between the two adjacent electrodes.

[0017] In some embodiments, the width of each upper electrode is 30 μm to 150 μm; the physical distance between two adjacent upper electrodes is 50 μm to 200 μm.

[0018] In other embodiments, the thickness of the lower electrode layer is 0.3 μm to 1.5 μm.

[0019] In some other embodiments, the thickness of the piezoelectric material layer is 5 μm to 30 μm.

[0020] In some embodiments, the thickness of the upper electrode layer is 0.3 μm to 1.5 μm.

[0021] In other embodiments, the thickness of the protective layer is 3 μm to 40 μm; or the thickness of the protective layer is 3 μm to 20 μm; or the thickness of the protective layer is 12 μm to 36 μm; or the thickness of the protective layer is 12 μm to 30 μm.

[0022] In some other embodiments, a plurality of first connecting pads are arranged linearly, with a physical spacing of 70 μm between two adjacent first connecting pads; a plurality of second connecting pads are arranged linearly, with a physical spacing of 70 μm between two adjacent second connecting pads.

[0023] In a second aspect, the present invention provides a fingerprint recognition device, including the ultrasonic sensor described in any of the first aspects of the present invention.

[0024] In a third aspect, the present invention provides an electronic device including the fingerprint recognition device described in the second aspect.

[0025] By using the ultrasonic sensor, fingerprint recognition device, and electronic device provided above, this utility model embodiment, by setting the first chip on the substrate and electrically connecting it with the piezoelectric transducer set on the same substrate, not only eliminates the need to set the TFT circuit on the substrate, thereby reducing the size of the ultrasonic sensor, or setting a larger piezoelectric transducer on the same size substrate, but also shortens the electrical transmission path between the piezoelectric transducer and the first chip, which is beneficial to improving the signal-to-noise ratio of the sensing signal, improving the signal transmission quality, thereby improving the performance of the ultrasonic sensor, and reducing the size of the sensor module. Attached Figure Description

[0026] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0027] Figure 1 A schematic diagram of a conventional ultrasonic sensing device is shown;

[0028] Figure 2 A schematic diagram of an ultrasonic sensor according to some embodiments of the present invention is shown;

[0029] Figure 3 A schematic diagram of an ultrasonic sensor including a second chip according to an embodiment of the present invention is shown;

[0030] Figure 4a A schematic diagram of an ultrasonic sensor with a second chip disposed on a first connecting board according to some embodiments of the present invention is shown;

[0031] Figure 4b It shows Figure 4a The diagram shows one usage state of the ultrasonic sensor.

[0032] Figure 5a A schematic diagram of an ultrasonic sensor with a second chip disposed on a first connecting board according to other embodiments of the present invention is shown;

[0033] Figure 5b It shows Figure 5a A schematic diagram of an ultrasonic sensor as shown from the B-direction view;

[0034] Figure 6 A side view schematic diagram of an ultrasonic sensor according to other embodiments of the present invention is shown;

[0035] Figure 7 A schematic diagram of a piezoelectric transducer including a strip electrode according to an embodiment of the present invention is shown;

[0036] Figure 8a A top view schematic diagram of an ultrasonic sensor with an exposed connecting pad according to some embodiments of the present invention is shown;

[0037] Figure 8b It shows Figure 8a A side view of the ultrasonic sensor;

[0038] Figure 8c A schematic diagram of an ultrasonic sensor with a first chip and a second chip installed is shown. Detailed Implementation

[0039] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0040] It should be understood that the terms "comprising" and "including" used in the specification and claims of this utility model indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0041] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0042] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0043] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0044] Figure 2Schematic diagrams of ultrasonic sensors according to some embodiments of the present invention are shown. For example... Figure 2 As shown, the ultrasonic sensor 200 may include: a substrate 210; a piezoelectric transducer 111 disposed on the substrate 210; and a first chip 221 disposed on the substrate 210 and electrically connected to the piezoelectric transducer 111. The first chip 221 may include one of a transmitting chip, a receiving chip, and an integrated chip, wherein the integrated chip integrates the circuitry of the transmitting chip and the receiving chip.

[0045] The substrate 210 is the underlying support structure of the ultrasonic sensor 200, providing a base platform for mounting and fixing other components such as the piezoelectric transducer 111 and the first chip 221. The substrate 210 may include at least one layer of circuit traces to form electrical connections to the components arranged on the substrate. In some embodiments, the substrate 210 may be one or more combinations of glass substrate, ceramic substrate, or silicon substrate.

[0046] The piezoelectric transducer 111, disposed on the substrate 210, is a key component in the ultrasonic sensor that enables the conversion between electrical energy and acoustic energy. Utilizing the properties of piezoelectric materials, the piezoelectric transducer 111 converts electrical signals transmitted from the transmitting chip into ultrasonic signals for transmission, or converts received ultrasonic signals into electrical signals for transmission to the receiving chip. In some embodiments, the type of piezoelectric transducer may include, but is not limited to, transducers made of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE), ceramic piezoelectric materials (such as aluminum nitride AlN), or microelectromechanical systems (MEMS).

[0047] The first chip 221 is the core component of the ultrasonic sensor 200 for signal processing and control. It is mounted on the substrate 210 and can be electrically connected to the piezoelectric transducer 111 via, for example, leads or circuit traces on the substrate. The first chip 221 can be a transmitter chip, a receiver chip, or an integrated chip. The main function of the transmitter chip (Tx chip) is to control and / or drive the transmission of ultrasonic signals. It generates electrical signals of specific frequency, amplitude, and waveform, which are then converted into ultrasonic signals by the piezoelectric transducer and transmitted. The receiver chip (Rx chip) is mainly used to receive and process the ultrasonic signals sensed by the piezoelectric transducer. It amplifies and filters weak electrical signals to extract useful information. An integrated chip integrates the circuitry of the transmitter and receiver chips. Through semiconductor manufacturing processes, it integrates the transmission and reception-related circuit modules onto the same chip, achieving a more compact design and more efficient signal processing.

[0048] In some embodiments, the area ratio of the piezoelectric transducer 111 to the surface area of ​​its substrate is greater than 0.6. For example, the area ratio of the piezoelectric transducer 111 to the surface area of ​​its substrate may be 0.61, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, or 0.9, etc. In other embodiments, the area ratio of the piezoelectric transducer 111 to the surface area of ​​its substrate is greater than 0.7. In still other embodiments, the area ratio of the piezoelectric transducer 111 to the surface area of ​​its substrate is greater than 0.8.

[0049] Compared to ultrasonic sensing devices that use TFT circuits (e.g.) Figure 1 As shown in the diagram, the ultrasonic sensor according to this embodiment significantly improves the fill factor. In an ultrasonic sensor, a higher fill factor means that the effective sensing area of ​​the piezoelectric transducer 111 occupies a larger proportion of the substrate 210, which can improve the utilization rate of the substrate and thus reduce costs. It also enables more efficient transmission and reception of ultrasonic signals, thereby improving the sensor's ability to capture and detect ultrasonic signals. This is crucial for improving the performance of ultrasonic sensors, especially in high-resolution and high-precision applications (such as ultrasonic fingerprint recognition).

[0050] The above combination Figure 2 An exemplary description of an ultrasonic sensor according to an embodiment of the present invention has been provided. It is understood that by placing the first chip on the substrate and electrically connecting it to the piezoelectric transducer, the signal transmission path is shortened, reducing signal loss and interference caused by long-distance transmission, improving signal quality and transmission efficiency, thereby effectively enhancing the performance of the ultrasonic sensor. Simultaneously, since the chips related to the transmitting and / or receiving functions are directly integrated on the substrate, there is no need to rely on traditional TFT processes, thus avoiding the limitations of large TFT circuit area, low operating frequency, and slow processing speed. This facilitates the realization of smaller sensors and improves the fill factor (the ratio of sensing area to sensor size), making the ultrasonic sensor of this embodiment suitable for high-frequency applications. For example, beamforming technology can be used to obtain higher ultrasonic energy and improve the signal-to-noise ratio of the device. Furthermore, this structure provides flexibility, allowing the selection of a transmitting chip, receiving chip, or integrated chip according to specific application requirements, optimizing the production process and cost control. It is also understood that… Figure 2 The ultrasonic sensor shown is exemplary and not limiting; for example, the substrate may not be limited to just one type of chip, but may include multiple types of chips. The following will combine... Figure 3 Further explanation.

[0051] Figure 3A schematic diagram of an ultrasonic sensor including a second chip according to an embodiment of the present invention is shown. Figure 3 As shown, the ultrasonic sensor 200 may include a substrate 210, a piezoelectric transducer 111, a first chip 221, and a second chip 222, wherein the piezoelectric transducer 111, the first chip 221, and the second chip 222 are all disposed on the substrate 210. The second chip 222 includes one of a transmitting chip and a receiving chip, and the first chip 221 includes the other of a transmitting chip and a receiving chip.

[0052] In some embodiments, at least one of the first chip 221 and the second chip 222 may be disposed on a substrate on the side of the piezoelectric transducer 111. In other embodiments, the first chip 221 and the second chip 222 may be disposed on the same side of the substrate of the piezoelectric transducer 111, or disposed on substrates on opposite sides of the piezoelectric transducer 111.

[0053] For example, such as Figure 3 As shown, the first chip 221 and the second chip 222 can be disposed on the substrate 210 on both sides of the piezoelectric transducer 111. The piezoelectric transducer 111, the first chip 221 and the second chip 222 can be disposed on the same surface of the substrate 210. Through circuit traces or lead connections on the substrate 210, the first chip 221 and the second chip 222 are electrically connected to the piezoelectric transducer 111, thereby realizing effective signal transmission and interaction.

[0054] In some embodiments, the first chip 221 can be a transmitting chip, and the second chip 222 can be a receiving chip. In other embodiments, the first chip 221 can be a receiving chip, and the second chip 222 can be a transmitting chip. The first chip 221 and the second chip 222 respectively perform the functions of transmitting and receiving, and work together to control and process the ultrasonic signal.

[0055] By using two independent chips, the first and second chips, the design can be optimized for each chip's function. For example, the transmitting chip can focus on efficient signal transmission, employing a high-voltage chip process to enhance transmission capabilities; while the receiving chip can focus on receiving and processing weak signals, employing a low-voltage chip process to reduce power consumption and improve sensitivity. This fully leverages the strengths of each chip, improving overall performance. Compared to integrated chips, which are limited by a single manufacturing process (requiring a high-voltage chip process), separating the transmitting and receiving functions onto two independent chips, and selecting the most suitable manufacturing process for each function, helps save manufacturing costs and reduces electromagnetic interference between the two, minimizing signal crosstalk and thus improving signal accuracy and stability. Furthermore, independent chips can distribute heat more effectively, contributing to chip stability and lifespan, and can be flexibly arranged to meet different design requirements and space constraints.

[0056] In some embodiments, the first chip 221 and the second chip 222 may be disposed on opposite sides of the piezoelectric transducer 111 to form a symmetrical layout. In other embodiments, the first chip 221 and the second chip 222 may be disposed on adjacent sides of the piezoelectric transducer 111 (e.g., Figure 3 (As shown in the diagram). The first chip 221 and the second chip 222 can be, for example... Figure 3 The bar shape shown can also be set to other shapes as needed.

[0057] The above combination Figure 3 An exemplary description has been provided of an ultrasonic sensor with two chips disposed on a substrate according to an embodiment of the present invention. It is understood that by directly disposing the first chip 221 and the second chip 222 next to the piezoelectric transducer 111 on the substrate 210, and on different sides of the piezoelectric transducer 111, the distance between the piezoelectric transducer 111 and the receiving chip and transmitting chip is relatively short, shortening the transmission path. This helps reduce the impact of parasitic capacitance on the signal and driving energy, thereby reducing driving current and signal transmission loss, lowering overall product power consumption, and improving product performance. It is also understood that... Figure 3 The ultrasonic sensor shown is exemplary. For example, the first chip and the second chip may not be separately disposed on substrates on opposite sides of the piezoelectric transducer, but may be disposed on the same substrate on the same side of the piezoelectric transducer. Also, for example, the second chip may not be limited to being disposed on the substrate, but may be disposed on the first connecting plate as needed. The following will combine... Figures 4a to 5b An exemplary description is provided.

[0058] Figure 4a A schematic diagram of an ultrasonic sensor with a second chip disposed on a first connecting board according to some embodiments of the present invention is shown. Figure 4b It shows Figure 4a The diagram shows one usage state of the ultrasonic sensor. Figure 4a and Figure 4b As shown, the ultrasonic sensor 200 may include a substrate 210, a piezoelectric transducer 111 disposed on the substrate 210, and a first chip 221, and also includes a first connecting plate 310 and a second chip 222 disposed on the first connecting plate 310, wherein the first connecting plate 310 is connected to the substrate 210, the second chip 222 includes one of a transmitting chip and a receiving chip, and the first chip 221 includes the other of a transmitting chip and a receiving chip.

[0059] In this embodiment, the first connecting plate 310 is connected to the substrate 210, serving as a bridge and providing a mounting position for the second chip 222. The second chip 222 is disposed on the first connecting plate 310, and its function is to undertake one part of the transmission or reception function, while the first chip 221 undertakes the other part. Specifically, if the second chip 222 is a transmitting chip, then the first chip 221 is a receiving chip, and vice versa, which will not be elaborated further here. This structural design allows the size of the substrate 210 to be further reduced, and allows those skilled in the art to flexibly configure the position and function of the chips according to the actual needs of the ultrasonic sensor, which helps to optimize the internal spatial layout of the sensor and improve the overall performance and applicability of the sensor.

[0060] In some embodiments, the first connecting plate 310 may include a flexible circuit board. In other embodiments, the connection between the first connecting plate 310 and the substrate 210 can be achieved by bonding, welding, snap-fitting, or other methods. In still other embodiments, the connection between the first connecting plate 310 and the substrate 210 can be achieved by ACF bonding. ACF bonding is a process for connecting electronic components using anisotropic conductive film (ACF). It mainly utilizes ACF under high temperature and high pressure to arrange conductive particles in the film to form conductive channels, thereby achieving electrical connection between the first connecting plate and the substrate. At the same time, after ACF is cured, it remains insulated in the planar direction (i.e., the direction parallel to the connection surface), avoiding short circuits. Compared with traditional welding processes, ACF bonding has the advantages of fine pitch and high reliability, enabling higher integration and smaller package size, which is in line with the development trend of modern electronic products being thinner and smaller.

[0061] In other embodiments, the second chip 222 can be mounted on the first connection board via SMT (Surface Mount Technology). In still other embodiments, the second chip 222 and the substrate 210 can be respectively connected to different sides of the first connection board 310 (e.g., Figure 4a As shown in the diagram, the connection point between the substrate 210 and the first connecting plate 310 and the second chip 222 are respectively located on two different surfaces of the first connecting plate 310. In other embodiments, the second chip 222 and the substrate 210 may be connected to the same surface of the first connecting plate 310, that is, the connection point between the substrate 210 and the first connecting plate 310 and the second chip 222 may be located on the same surface of the first connecting plate 310.

[0062] In such Figure 4a In one usage state of the ultrasonic sensor shown, the first connecting plate 310 can be bent toward the piezoelectric transducer 111. Figure 4bIt shows Figure 4a The view shown from direction A after the first connecting plate 310 is bent. Figure 4b As shown, after the first connecting plate 310 is bent toward the piezoelectric transducer 111, the second chip 222 can be located on the side of the first connecting plate 310 facing the piezoelectric transducer 111. In other embodiments, the second chip 222 may not be limited to being located on the side of the first connecting plate 310 facing the piezoelectric transducer 111, but may also be located on the other side of the first connecting plate 310 away from the piezoelectric transducer 111.

[0063] Figure 5a A schematic diagram of an ultrasonic sensor with a second chip disposed on a first connection board is shown in some other embodiments of the present invention. Figure 5b It shows Figure 5a A schematic diagram of an ultrasonic sensor as shown from the B-direction view. (See diagram below.) Figure 5a and Figure 5b As shown, the ultrasonic sensor 200 may include a substrate 210, a piezoelectric transducer 111 disposed on the substrate 210, and a first chip 221, and also includes a first connecting plate 310 and a second chip 222 disposed on the first connecting plate 310, wherein the first connecting plate 310 is connected to the substrate 210, the second chip 222 includes one of a transmitting chip and a receiving chip, and the first chip 221 includes the other of a transmitting chip and a receiving chip.

[0064] and Figure 4a and Figure 4b The ultrasonic sensor shown is different from the one shown. Figure 5a and Figure 5b The first connection plate 310 of the ultrasonic sensor shown may include a connection portion 311 and an extension portion 312. The connection portion 311 is connected to the substrate 210, and the extension portion 312 is connected to the connection portion 311. The second chip 222 is disposed on the extension portion 312. The extension portion 312 may extend toward the piezoelectric transducer 111. In some embodiments, such as Figure 5b As shown, the second chip 222 can be disposed on the side of the extension 312 facing away from the piezoelectric transducer 111. In other embodiments, the second chip 222 may not be limited to being disposed on the side of the extension 312 facing away from the piezoelectric transducer 111, but may also be disposed on the side of the extension 312 facing the piezoelectric transducer 111.

[0065] Through the above Figures 4a to 5b This configuration allows the second chip to be placed on the first connection board and connected to the substrate when substrate space is insufficient, effectively solving the substrate space limitation problem. Figures 4b to 5b This configuration allows for a narrow-width design of the ultrasonic sensor, meeting the needs of specific product applications, such as side-mounted fingerprint applications on electronic devices.

[0066] The above combination Figures 2-5b The chip arrangement in the ultrasonic sensor of this utility model embodiment has been described in detail below, in conjunction with... Figure 6 A detailed explanation of the piezoelectric transducer in the ultrasonic sensor is provided.

[0067] Figure 6 A side view schematic diagram of an ultrasonic sensor according to other embodiments of the present invention is shown. For example... Figure 6 As shown in the figure, the piezoelectric transducer 111 in the ultrasonic sensor of this embodiment can adopt a multi-layer structure, including a lower electrode layer 610, a piezoelectric material layer 620, and an upper electrode layer 630. The piezoelectric material layer 620 is located between the lower electrode layer 610 and the upper electrode layer 630, and the lower electrode layer 610 is located between the substrate 210 and the piezoelectric material layer 620. The upper electrode layer 610 and the lower electrode layer 630 are conductive layers of the piezoelectric transducer 111. One of the upper electrode layer 630 and the lower electrode layer 610 is used to connect with the receiving chip ( Figure 6 (Not shown in the image) is electrically connected, and the other of the two is used to connect with the transmitter chip ( Figure 6 Electrical connection (not shown). This structure enables the piezoelectric transducer 111 to apply voltage or collect signals through the upper electrode layer 630 and the lower electrode layer 610, thereby realizing the conversion of electrical energy into acoustic energy.

[0068] In some embodiments, the thickness of the lower electrode layer 610 is 0.3 μm to 1.5 μm. Exemplarily, the thickness of the lower electrode layer 610 can be 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, or other values ​​within the range of 0.3 μm to 1.5 μm.

[0069] In some embodiments, the thickness of the upper electrode layer 630 is 0.3 μm to 1.5 μm. Exemplarily, the thickness of the upper electrode layer 630 can be 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc., or other values ​​within the range of 0.3 μm to 1.5 μm.

[0070] In some other embodiments, the thickness of the piezoelectric material layer 620 is 5 μm to 30 μm. Exemplarily, the thickness of the piezoelectric material layer 620 can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, or other values ​​within the range of 5 μm to 30 μm. In some embodiments, the piezoelectric material layer 620 may include one or more of a polyvinylidene fluoride layer (PVDF layer) and a polyvinylidene fluoride-trifluoroethylene copolymer layer (PVDF-TrFE layer).

[0071] In other embodiments, the ultrasonic sensor may further include a protective layer 640, which at least covers the upper electrode layer 630. In other embodiments, the thickness of the protective layer 640 is 3 μm to 40 μm. For example, the thickness of the protective layer 640 can be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, or other values ​​within the range of 3μm to 40μm. In some other embodiments, the thickness of the protective layer 640 is 3μm to 20μm. In some embodiments, the thickness of the protective layer 640 is 12 μm to 36 μm. In other embodiments, the thickness of the protective layer 640 is 12 μm to 30 μm.

[0072] Different protective layer thicknesses are suitable for different application scenarios and manufacturing process requirements. The selection of the protective layer thickness can be determined based on the resonant frequency of the piezoelectric transducer 111. Specifically, different materials (such as OLEDs or metals) have different propagation and attenuation characteristics for ultrasonic signals. Selecting an appropriate resonant frequency based on the application scenario, and then selecting an appropriate protective layer thickness based on the resonant frequency, can help optimize the performance and signal quality of the ultrasonic sensor.

[0073] For example, in some scenarios, the resonant frequency range for ultrasonic sensors located beneath OLEDs (Organic Light-Emitting Diodes) can be 15MHz to 30MHz, or 15MHz to 25MHz. In other scenarios, for ultrasonic sensors located beneath metal, the resonant frequency is typically higher than 30MHz. Generally, the higher the required resonant frequency, the thinner the protective layer should be.

[0074] The above combination Figure 6 An exemplary description of a piezoelectric transducer employing a multilayer structure has been provided, and will be discussed below in conjunction with... Figure 7 A specific implementation of the piezoelectric transducer is further described.

[0075] Figure 7 A schematic diagram of a piezoelectric transducer including a strip electrode according to an embodiment of the present invention is shown. Figure 7 As shown, the piezoelectric transducer disposed on the substrate 210 includes an upper electrode layer 630, a piezoelectric material layer 620, and a lower electrode layer 610. The lower electrode layer 610 may include a plurality of parallel strip-shaped lower electrodes 612, each lower electrode 612 leading out a corresponding first connecting pad 611. The upper electrode layer 630 may include a plurality of parallel strip-shaped upper electrodes 632, each upper electrode leading out a corresponding second connecting pad 631. The plurality of lower electrodes 612 of the lower electrode layer 610 and the plurality of upper electrodes 632 of the upper electrode layer 630 are orthogonally arranged.

[0076] A first connection pad 611 is disposed on the substrate 210 and is used to connect the lower electrode layer 610 to an external circuit (such as a first chip or a second chip). The first connection pad 611 and the corresponding lower electrode 612 can be electrically connected via, for example, leads or circuit traces on the substrate 210. A second connection pad 631 is disposed on the substrate 210 and is used to connect the upper electrode layer 630 to an external circuit (such as a first chip or a second chip). The second connection pad 631 and the corresponding upper electrode 632 can be electrically connected via, for example, leads or circuit traces on the substrate 210. In some embodiments, the first connection pad 611 and / or the second connection pad 631 can be implemented by forming a metallized region on the substrate 210 or by providing pads on the substrate 210.

[0077] The multiple lower electrodes 612 of the lower electrode layer 610 and the multiple upper electrodes 632 of the upper electrode layer 630 are orthogonally arranged, that is, the multiple lower electrodes 612 and the multiple upper electrodes 632 are perpendicular to each other. The orthogonal arrangement of the upper and lower electrodes can reduce mutual interference between the electrodes, improve signal transmission efficiency and quality, and thus improve the performance of the ultrasonic sensor.

[0078] In some embodiments, the width of each upper electrode 632 is 30 μm to 150 μm. Exemplarily, the width of each upper electrode 632 can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, etc., or other values ​​within the range of 30 μm to 150 μm.

[0079] In other embodiments, the physical pitch P between two adjacent upper electrodes 632 is 50 μm to 200 μm. Exemplarily, the physical pitch P between two adjacent upper electrodes 632 can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, etc., or other values ​​within the range of 50 μm to 200 μm.

[0080] The physical distance P is the distance between the centers of two adjacent points. Figure 7 As shown in the example, the physical distance P between two adjacent upper electrodes 632 is the distance between the center lines of the two adjacent upper electrodes 632 in their respective extension directions (or length directions). Based on the physical distance P between two adjacent upper electrodes 632 and the width of each upper electrode 632, the gap distance between two adjacent upper electrodes 632 can be determined.

[0081] In some other embodiments, the width of each lower electrode 612 is 30 μm to 150 μm. Exemplarily, the width of each lower electrode 612 can be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 150 μm, etc., or other values ​​within the range of 30 μm to 150 μm. The width of the lower electrode 612 can be the same as or different from the width of the upper electrode 632, and can be set as needed.

[0082] In some embodiments, the physical distance P between two adjacent lower electrodes 612 is 50 μm to 200 μm. Exemplarily, the physical distance P between two adjacent lower electrodes 612 can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, etc., or other values ​​within the range of 50 μm to 200 μm. The physical distance between two adjacent upper electrodes can be set to be the same as or different from the physical distance between two adjacent lower electrodes, depending on the application requirements.

[0083] In piezoelectric transducer design, the number and arrangement of electrodes directly affect the transducer's performance. Controlling the physical spacing between adjacent upper electrodes and adjacent lower electrodes within the range of 50μm to 200μm allows for a more compact electrode layout, enabling the integration of more electrodes on the same substrate area. This more compact layout allows for higher resolution or higher signal acquisition density, thereby improving the performance and functionality of the piezoelectric transducer. Furthermore, appropriate physical spacing reduces inter-electrode interference, such as parasitic capacitance and crosstalk, improving signal transmission accuracy and stability, and enhancing the performance of ultrasonic sensors. For example, in high-frequency applications, inter-electrode interference significantly affects signal quality; by precisely controlling the physical spacing between adjacent electrodes, this interference can be effectively reduced, ensuring signal integrity and reliability.

[0084] In some other embodiments, the plurality of first connecting pads 611 may be arranged linearly, with a physical spacing of 70 μm between adjacent first connecting pads 611; similarly, the plurality of second connecting pads 631 may be arranged linearly, with a physical spacing of 70 μm between adjacent second connecting pads 631. Linear arrangement means arrangement along a straight line. The physical spacing between adjacent first connecting pads 611 may be the distance between the center points of the two adjacent first connecting pads 611. Similarly, the physical spacing between adjacent second connecting pads 631 may be the distance between the center points of the two adjacent second connecting pads 631.

[0085] In other embodiments, the physical spacing between two adjacent lower electrodes 612 can be greater than or equal to the physical spacing between two adjacent first connecting pads 611; the physical spacing between two adjacent upper electrodes 632 can be greater than or equal to the physical spacing between two adjacent second connecting pads 631. The physical spacing between two adjacent lower electrodes 612 being greater than the physical spacing between two adjacent first connecting pads 611 forms a finger-like electrode structure, which allows for a more compact arrangement of the multiple first connecting pads 611, saving space on the substrate 210. Similarly, the physical spacing between two adjacent upper electrodes 632 being greater than the physical spacing between two adjacent second connecting pads 631 forms a finger-like electrode structure, which allows for a more compact arrangement of the multiple second connecting pads 631, saving space on the substrate 210.

[0086] In some embodiments, an output connection pad 711 may also be provided on the substrate 210 for an electrical interface between the piezoelectric transducer and an external system, so as to transmit the electrical signal generated by the piezoelectric transducer to the external system, or to transmit the electrical signal from the external system to the piezoelectric transducer. The output connection pad 711 can be implemented by forming a metallized region on the substrate 210 or by providing pads on the substrate 210. Simultaneously, the output connection pad 711 can be electrically connected to the first connection pad 611 and the second connection pad 631 via leads or circuit traces on the substrate 210. In other embodiments, the number of first connection pads 611 may be greater than the number of lower electrodes 612 to facilitate electrical connection with the output connection pad 711; the number of second connection pads 631 may be greater than the number of upper electrodes 632 to facilitate electrical connection with the output connection pad 711.

[0087] The above combination Figure 7 An exemplary implementation of a piezoelectric transducer disposed on a substrate has been described. It is understood that... Figure 7 The structures shown are exemplary and not limiting. For example, the number of upper electrodes 632 and lower electrodes 612 may not be limited to four as shown in the figure, and may be more or less as needed. Also, the first connecting pad 611 and the second connecting pad 631 may not be limited to being located on adjacent sides of the piezoelectric transducer as shown in the figure, but may be located on opposite sides of the piezoelectric transducer, or on the same side of the piezoelectric transducer as needed. When the first connecting pad and the second connecting pad are located on opposite sides of the piezoelectric transducer, the substrate 210 can be set as a long strip to reduce the width of the substrate, thus making it suitable for applications such as the side of an electronic device (e.g., the side of a mobile phone). In some embodiments, when the first connecting pad and the second connecting pad are located on the same side of the piezoelectric transducer, the first connecting pad and the second connecting pad can be used to connect an integrated chip. After introducing the implementation of the piezoelectric transducer, the following will combine... Figures 8a-8cThe ultrasonic sensor, including the protective layer, is described further.

[0088] Figure 8a A top view schematic diagram of an ultrasonic sensor with an exposed connecting pad is shown in some embodiments of the present invention. Figure 8b It shows Figure 8a A side view of the ultrasonic sensor. (Compared to...) Figure 7 Compared to the ultrasonic sensor shown, Figure 8a and Figure 8b The diagram shows the protective layer 640 covering the upper electrode layer 630 and the substrate surface. (Example) Figure 8a and Figure 8b As shown, the protective layer 640 can cover the upper electrode layer and the substrate surface where the piezoelectric transducer is located, exposing the first connecting pad 611 led out from the lower electrode layer and the second connecting pad 631 led out from the upper electrode layer.

[0089] The protective layer 640 covers the upper electrode layer and the surface of the substrate where the piezoelectric transducer is located, forming a protective structure to prevent damage or interference to the piezoelectric transducer. It exposes only the necessary connection pads on the substrate 210 for electrical connections, protecting the conductive paths and other components on the substrate 210. In some embodiments, the first connection pad 611 exposed from the protective layer 640 can be electrically connected to either the transmitting chip or the receiving chip, and the exposed second connection pad 631 can be electrically connected to the other of the transmitting chip and the receiving chip. In other embodiments, the exposed first connection pad 611 and second connection pad 631 can be electrically connected to an integrated chip.

[0090] In some embodiments, the ultrasonic sensor 200 may further include a second connection plate 710 for connecting to an external system. The second connection plate 710 is connected to the substrate 210, and the number of output connection pads 711 on the substrate 210 for connecting to the second connection plate 710 is less than the number of the first connection pads 611 and / or the second connection pads 631. The output connection pads 711 are exposed from the protective layer 640 to facilitate connection to the second connection plate 710.

[0091] The second connection board 710 may be a circuit board for connecting the ultrasonic sensor to an external system (such as a CPU, host, or other device) to achieve electrical connection and signal transmission between the sensor and the external system. In other embodiments, the second connection board 710 may be a flexible circuit board or a printed circuit board.

[0092] Understandably, in conventional technologies, when the transmitting and receiving chips are mounted on a second connecting plate, the number of output connection pads required is at least equal to the sum of the number of the first and second connection pads to enable signal transmission between the piezoelectric transducer and the transmitting and receiving chips. In contrast, in the ultrasonic sensor of this embodiment, since at least the first chip is mounted on the substrate 210 (i.e., mounted on the substrate 210 via the first connection pad 611 and / or the second connection pad 631), the number of output connection pads 711 can be less than the number of the first connection pad 611 and / or the second connection pad 631, thereby significantly reducing the number of output connection pads required to connect the substrate and the second connecting plate 710. Furthermore, since the width of the second connecting plate needs to be adapted to the size of the area where the output connection pads are located, compared to conventional technologies, the ultrasonic sensor solution of this embodiment can effectively reduce the size of the second connecting plate, thereby reducing the manufacturing cost of the second connecting plate and facilitating the miniaturization of sensors.

[0093] In some embodiments, Figure 8a and Figure 8b The ultrasonic sensor shown can be implemented, for example, as follows: First, a first metal layer (such as copper, aluminum, or gold) can be deposited on substrate 210 using physical vapor deposition (PVD) or electroplating. After exposure and development, the first metal layer is patterned to form the finger electrode structure of the lower electrode 612 and the winding pattern connected to the first connecting pad (i.e., the circuit structure between the first connecting pad and the output connecting pad). Next, a piezoelectric material layer 620 can be formed on the lower electrode 612 using coating or screen printing. Then, a second metal layer (such as copper, aluminum, or gold) is formed on the piezoelectric material layer 620 again using PVD or electroplating. Similarly, it is patterned through exposure and development to form the finger electrode structure of the upper electrode 632 and the winding pattern connected to the second connecting pad (i.e., the circuit structure between the second connecting pad and the output connecting pad). Subsequently, a protective layer 640 is formed on the surface of the substrate 210 using photoresist or ink as the main material through coating or screen printing processes; then the protective layer 640 is patterned through exposure, development or screen printing processes to expose the first connection pad, the second connection pad and the output connection pad.

[0094] Finally, anisotropic conductive adhesive (ACF) is used to connect the first chip, the second chip, and the second connecting plate to corresponding positions on the substrate 210, resulting in, for example... Figure 8c The ultrasonic sensor shown. Figure 8c A schematic diagram of an ultrasonic sensor with a first chip 221 and a second chip 222 installed is shown. Figure 8cAs shown, the first chip 221 can be electrically connected to the second connection pad 631 exposed from the protective layer 640, and the second chip 222 can be electrically connected to the first connection pad 611 exposed from the protective layer 640. In other embodiments, the first chip 221 can be electrically connected to the first connection pad 611, and the second chip 222 can be electrically connected to the second connection pad 631.

[0095] The above combination Figures 8a-8c The ultrasonic sensor including a protective layer of some embodiments of the present invention has been described by way of example. It is understood that the above description is exemplary and not restrictive. For example, the first connecting pad and the second connecting pad may not be limited to being disposed on the substrate as shown in the figure. In other embodiments, when the ultrasonic sensor also includes a first connecting plate, the first connecting pad or the second connecting pad may be disposed on the first connecting plate to be electrically connected to the second chip on the second connecting plate.

[0096] In summary, this utility model provides an ultrasonic sensor. By placing at least a first chip on a substrate and electrically connecting it to a piezoelectric transducer also placed on the substrate, it is beneficial to shorten the transmission path between the piezoelectric transducer and the first chip, improve the signal processing performance of the ultrasonic sensor, and reduce the size of the ultrasonic sensor to meet the development needs of lightweight, thin, and small ultrasonic sensors.

[0097] In a second aspect, this utility model provides a fingerprint recognition device, which may include the aforementioned... Figures 2-8c The ultrasonic sensor described in any one of the present invention has several advantages, such as small size, high fill factor, low power consumption, and excellent performance (e.g., effectively reducing signal transmission loss and improving signal-to-noise ratio). These characteristics make it perform well in fingerprint recognition applications, enabling high-precision and high-reliability fingerprint recognition. Therefore, the fingerprint recognition device of the present invention has broad application prospects in various devices requiring fingerprint recognition functionality.

[0098] This invention further provides an electronic device in a third aspect, including the fingerprint recognition device described in the second aspect of this invention. By employing the fingerprint recognition device of this invention, the electronic device can achieve fast, accurate, and secure user identification and verification functions. This not only improves the security and user experience of the electronic device but also expands its functions and application scenarios. For example, the electronic device can utilize fingerprint recognition to perform various security-related operations such as unlocking, payment verification, and data protection, meeting user needs in different scenarios, such as smartphones, tablets, laptops, smart home devices, and security equipment. Furthermore, the fingerprint recognition device according to this invention can be adapted to different installation locations of electronic devices, such as those described above. Figures 2-8c Any of the described ultrasonic sensors can meet the requirement of placing a fingerprint recognition device below the screen of an electronic device or below the back panel of an electronic device, or a combination thereof. Figures 4b-5b Any of the ultrasonic sensors described herein can meet the requirement of placing a fingerprint recognition device on the lower side of an electronic device.

[0099] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and intent of the present invention. It should be understood that various alternatives to the embodiments of the present invention described herein may be employed in the practice of the present invention. The appended claims are intended to define the scope of protection of the present invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An ultrasonic sensor, characterized in that, include: substrate; A piezoelectric transducer is disposed on the substrate; A first chip is disposed on the substrate and electrically connected to the piezoelectric transducer. The first chip includes one of a transmitter chip, a receiver chip, and an integrated chip, wherein the integrated chip integrates the circuitry of the transmitter chip and the receiver chip.

2. The ultrasonic sensor according to claim 1, characterized in that, The ultrasonic sensor further includes a second chip, which comprises one of the transmitting chip and the receiving chip, and the first chip comprises the other of the transmitting chip and the receiving chip; and At least one of the first chip and the second chip is disposed on a substrate on the side of the piezoelectric transducer.

3. The ultrasonic sensor according to claim 2, characterized in that, The first chip and the second chip are disposed on the same side of the substrate of the piezoelectric transducer, or on separate substrates on opposite sides of the piezoelectric transducer.

4. The ultrasonic sensor according to claim 2, characterized in that, The ultrasonic sensor also includes: A first connecting plate is connected to the substrate; The second chip is mounted on the first connection board.

5. The ultrasonic sensor according to claim 4, characterized in that, The first connecting plate includes a connecting portion and an extension portion. The connecting portion is connected to the substrate, and the extension portion is connected to the connecting portion. The second chip is disposed on the extension portion.

6. The ultrasonic sensor according to any one of claims 1-5, characterized in that, The ratio of the area of ​​the piezoelectric transducer to the area of ​​the substrate it is located on is greater than 0.

6.

7. The ultrasonic sensor according to any one of claims 1-5, characterized in that, The piezoelectric transducer includes a lower electrode layer, a piezoelectric material layer, and an upper electrode layer. The piezoelectric material layer is located between the lower electrode layer and the upper electrode layer, and the lower electrode layer is located between the substrate and the piezoelectric material layer. The ultrasonic sensor also includes a protective layer that covers the upper electrode layer and the substrate surface where the piezoelectric transducer is located, exposing the first connecting pad led out from the lower electrode layer and the second connecting pad led out from the upper electrode layer.

8. The ultrasonic sensor according to claim 7, characterized in that, The exposed first connection pad is electrically connected to one of the transmitting chip and the receiving chip, and the exposed second connection pad is electrically connected to the other of the transmitting chip and the receiving chip; or The exposed first and second connection pads are electrically connected to the integrated chip.

9. The ultrasonic sensor according to claim 7, characterized in that, The ultrasonic sensor further includes a second connection plate for connecting to an external system. The second connection plate is connected to the substrate, and the number of output connection pads on the substrate for connecting to the second connection plate is less than the number of the first connection pads and / or the number of the second connection pads.

10. The ultrasonic sensor according to claim 7, characterized in that, The lower electrode layer includes a plurality of parallel strip-shaped lower electrodes, wherein each lower electrode leads out a corresponding first connection pad; The upper electrode layer includes a plurality of parallel strip-shaped upper electrodes, wherein each upper electrode leads out a corresponding second connection pad; The plurality of lower electrodes of the lower electrode layer and the plurality of upper electrodes of the upper electrode layer are arranged orthogonally.

11. The ultrasonic sensor according to claim 10, characterized in that, The width of each of the lower electrodes is 30 μm to 150 μm; The physical distance between two adjacent lower electrodes is 50μm to 200μm, and the physical distance is the distance from the center to the center of the two adjacent electrodes.

12. The ultrasonic sensor according to claim 10, characterized in that, The width of each of the upper electrodes is 30 μm to 150 μm; The physical distance between two adjacent upper electrodes is 50μm to 200μm.

13. The ultrasonic sensor according to claim 7, characterized in that, The thickness of the lower electrode layer is 0.3 μm to 1.5 μm.

14. The ultrasonic sensor according to claim 7, characterized in that, The thickness of the piezoelectric material layer is 5 μm to 30 μm.

15. The ultrasonic sensor according to claim 7, characterized in that, The thickness of the upper electrode layer is 0.3 μm to 1.5 μm.

16. The ultrasonic sensor according to claim 7, characterized in that, The thickness of the protective layer is 3μm to 40μm; or The thickness of the protective layer is 3μm to 20μm; or The thickness of the protective layer is 12μm to 36μm; or The thickness of the protective layer is 12μm to 30μm.

17. The ultrasonic sensor according to claim 10, characterized in that, The plurality of first connecting pads are arranged linearly, with a physical spacing of 70 μm between two adjacent first connecting pads; the plurality of second connecting pads are arranged linearly, with a physical spacing of 70 μm between two adjacent second connecting pads.

18. A fingerprint recognition device, characterized in that, Includes the ultrasonic sensor described in any one of claims 1-17.

19. An electronic device, characterized in that, Includes the fingerprint recognition device as described in claim 18.

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