Ultrasonic sensor, sensor module, electronic device, and vehicle

Abstract

The embodiment of the application provides an ultrasonic sensor, a sensor module, an electronic device and a vehicle, and belongs to the technical field of electronic information. The ultrasonic sensor comprises a chip and a piezoelectric resonant unit. The piezoelectric layer group of the piezoelectric resonant unit generates ultrasonic waves. The ultrasonic waves propagate between the layers of the chip and the piezoelectric resonant unit to generate resonance superposition. The chip substrate and the packaging material of the chip are different, and the superposition effects generated by the chip substrate and the packaging material are different. After resonance superposition, at least two ultrasonic wave signals of different frequencies are formed, and then the chip can obtain at least two biometric information, thereby enriching the function of the ultrasonic sensor and meeting the needs of various application scenarios. By adjusting the thickness of each layer in the piezoelectric resonant unit, the thickness of the chip substrate and the thickness of the packaging, the frequency value of the ultrasonic wave signal can be designed, the frequency of the ultrasonic wave signal can be designed, different detection functions can be realized, the needs of different application scenarios can be matched, and the applicable scenarios of the ultrasonic sensor are enriched.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic information, in particular to an ultrasonic sensor, a sensor module, an electronic device and a vehicle. BACKGROUND

[0002] The ultrasonic sensor is a sensor that converts ultrasonic wave signals into other energy signals (usually electrical signals). Ultrasonic waves are mechanical waves with a vibration frequency higher than 20 kHz, and have characteristics such as high frequency, short wavelength, small diffraction, good directionality, and directional propagation as a ray, and are widely used in industries, national defense, biomedicine, and other fields.

[0003] Among them, in the aspect of biological feature detection and identification, ultrasonic fingerprint identification technology has become one of the main solutions for electronic devices to realize under-screen fingerprint identification. The ultrasonic sensor can emit ultrasonic waves of a preset frequency, and the ultrasonic waves can pass through the display screen, glass cover plate, etc. of the device and irradiate the user's finger, and the ultrasonic waves reflected by the finger are received by the ultrasonic sensor to obtain the user's fingerprint, thereby realizing fingerprint identification. With the continuous development of biological feature detection and identification technology, some devices have the detection and identification needs of multiple biological features such as fingerprint identification and heart rate detection. Therefore, an ultrasonic sensor capable of detecting multiple biological feature information is needed to match different application scenarios. SUMMARY

[0004] The embodiments of the present application provide an ultrasonic sensor, a sensor module, an electronic device and a vehicle. The ultrasonic sensor can emit at least two different frequencies of ultrasonic waves to obtain at least two biological feature information, meet the monitoring and identification needs of multiple biological features, and correspondingly match different application scenarios.

[0005] The first aspect of the embodiments of the present application provides an ultrasonic sensor, which includes a chip and a piezoelectric resonant unit. The chip includes a chip substrate and a packaging piece wrapped around the outer periphery of the chip substrate. The packaging piece is different from the molding material of the chip substrate.

[0006] The piezoelectric resonant unit includes a piezoelectric layer group and a protective layer group, which are stacked in sequence on one side of the chip. The piezoelectric layer group is configured to generate ultrasonic waves, which can propagate towards or away from the chip along the stacking direction. The membrane layers above (on the side away from the chip along the stacking direction) and below (on the side facing the chip along the stacking direction) the piezoelectric layer group, and the chip will form a resonance, and then ultrasonic wave resonance superposition occurs. Because the materials of the chip substrate and the packaging piece are different, the resonance superposition effects of the chip substrate and the packaging piece are different, so that after the ultrasonic waves pass through the resonance superposition of the chip, the piezoelectric layer group and the protective layer group, at least two different frequencies of ultrasonic wave signals can be formed.

[0007] At least two ultrasonic signals of different frequencies can be transmitted to the detection site (such as a finger). After being reflected, the ultrasonic signals of different frequencies can be transmitted to the piezoelectric layer group. The piezoelectric layer group is also configured to receive the reflected ultrasonic signals of different frequencies and convert them into electrical signals for transmission to the chip. The chip is configured to obtain at least two types of biometric information corresponding to the electrical signals, thereby realizing the detection of multiple types of biometric information, enriching the functions of the ultrasonic sensor, and meeting the needs of various application scenarios. In other words, using a single ultrasonic sensor can give the device the detection and identification functions of multiple types of biometric information, which helps to reduce the sensor structure within the device, simplify the structural layout design of the device, and reduce the device cost.

[0008] At least two ultrasonic signals of different frequencies include an ultrasonic signal of a preset frequency (i.e., an ultrasonic signal of a target frequency). Each layer in the piezoelectric resonant unit has a corresponding first preset thickness, and the chip substrate and the package have a second preset thickness and a third preset thickness, respectively. The first preset thickness, the second preset thickness, and the third preset thickness are set according to the frequency value of the ultrasonic signal of the preset frequency. In other words, the frequency value of the ultrasonic signal emitted by the ultrasonic sensor can be designed by designing the thickness of each layer in the piezoelectric resonant unit, the thickness of the chip substrate, and the thickness of the package to obtain an ultrasonic signal of the target frequency. Furthermore, it can be ensured that the ultrasonic signal of the target frequency has a strong intensity and a better efficiency, thereby realizing the designability of the ultrasonic signal frequency, thereby realizing different detection functions, matching the requirements of different application scenarios, and enriching the applicable scenarios of the ultrasonic sensor.

[0009] In a possible implementation, the piezoelectric resonance unit satisfies the condition: 0.1≤∑(h i / λ i )≤0.4, where h i is the first preset thickness corresponding to each layer in the piezoelectric resonance unit, λ i The wavelength of the preset frequency ultrasonic wave in each layer of the piezoelectric resonant unit is determined by the wavelength of the wave. This has a better resonance superposition effect on the ultrasonic wave, further improving the efficiency of the ultrasonic sensor and enhancing the intensity of the emitted ultrasonic signal, thereby improving the detection and recognition performance of the ultrasonic sensor.

[0010] In a possible implementation, the piezoelectric resonance unit satisfies the condition: ∑(h i / λ i )=1 / 4. It has a better resonance superposition effect, obtains better efficiency and stronger strength, and further helps to improve the performance of the ultrasonic sensor.

[0011] In a possible implementation, the ultrasonic sensor satisfies the condition: 0.3≤∑(h i / λ i )+(h a / λa )≤0.7, wherein h a is the second preset thickness or the third preset thickness, λ a is the wavelength of the preset frequency ultrasonic wave in the chip substrate or the package. This facilitates further improvement of the resonance superposition effect, thereby further improving the efficiency of the ultrasonic sensor and the intensity of the ultrasonic wave.

[0012] In a possible implementation, the ultrasonic sensor satisfies the condition:∑(h i / λ i )+(h a / λ a )=1 / 2. This achieves a more excellent resonance superposition effect, obtains better efficiency and stronger intensity, and further facilitates improvement of the performance of the ultrasonic sensor.

[0013] In a possible implementation, the second preset thickness and the third preset thickness are equal, the chip substrate and the package form a chip base with a uniform thickness, and the thickness of the chip base is negatively correlated with the frequency value of the preset frequency ultrasonic wave. The thickness of the chip base can be adjusted to obtain ultrasonic wave signals of different frequencies, the frequency of the ultrasonic wave can be designed, and thus the demand in different application scenarios can be matched.

[0014] In a possible implementation, the third preset thickness is negatively correlated with the frequency value of the preset frequency ultrasonic wave. The thickness of the package can also be adjusted to adjust the frequency of the preset frequency ultrasonic wave, thereby increasing the flexibility and applicability of the ultrasonic wave frequency adjustment.

[0015] In a possible implementation, the protection layer group includes the first adhesive layer and a protection layer, the protection layer is arranged on the piezoelectric layer group through the first adhesive layer, and the double-layer structure design of the protection layer group increases the number of layers of the piezoelectric resonance unit, facilitates enhancement of the resonance superposition effect on the ultrasonic wave, better improves the efficiency and intensity of the ultrasonic wave signal, and also increases the flexibility of the frequency value design of the ultrasonic wave signal.

[0016] In addition, when the ultrasonic sensor is formed, the protection layer can be directly bonded to the piezoelectric layer group through the first adhesive layer, the operation is more convenient, the forming step is simplified, and the production cost and efficiency of the forming are reduced.

[0017] In a possible implementation, the chip further includes a plurality of first pixel electrodes, and the plurality of first pixel electrodes are arrayed on one side of the chip substrate.

[0018] The piezoelectric layer group includes a redistribution layer, a piezoelectric layer, and an electrode layer which are sequentially stacked, the electrode layer is configured to apply a voltage excitation to the piezoelectric layer, the piezoelectric layer is configured to emit an ultrasonic wave under the voltage excitation, and the piezoelectric layer is further configured to receive a reflected ultrasonic wave signal and convert the ultrasonic wave signal into an electric signal.

[0019] The redistribution layer covers the plurality of first pixel electrodes, and a plurality of second pixel electrodes are arranged in an array on a side of the redistribution layer away from the chip, the plurality of second pixel electrodes are connected to the plurality of first pixel electrodes in a one-to-one correspondence, to realize electrical signal transmission between the first pixel electrodes and the second pixel electrodes, and the piezoelectric layer covers the plurality of second pixel electrodes. The redistribution layer can cover a side of the chip substrate and the package, and the redistribution layer can have a larger area than the chip substrate, so that the array area of the second pixel electrodes can be larger than the array area of the first pixel electrodes, and the electrical signal can be fanned out from the first pixel electrode array in the chip substrate to the second pixel electrode array with a larger area, to decouple the constraint between the area of the chip substrate and the area of the identification region, and to increase the area of the identification region by increasing the area of the redistribution layer and the second pixel electrode array, thereby increasing the area of the identification region without increasing the area of the chip substrate and the first pixel electrode array, and reducing the increase in cost.

[0020] In a possible implementation, the preset frequency ultrasonic wave includes one of high-frequency ultrasonic wave or low-frequency ultrasonic wave, and the frequency value of the high-frequency ultrasonic wave is higher than that of the low-frequency ultrasonic wave. The thickness of the chip substrate is 200 μm-50 μm, and the frequency value of the high-frequency ultrasonic wave is 8 Mhz-20 Mhz or 15 Mhz-25 Mhz. By adjusting the thickness of the chip substrate, the frequency value of the high-frequency ultrasonic wave can be more effectively adjusted to meet the frequency design requirement of the high-frequency ultrasonic wave.

[0021] In a possible implementation, the preset frequency ultrasonic wave includes one of high-frequency ultrasonic wave or low-frequency ultrasonic wave, and the frequency value of the high-frequency ultrasonic wave is higher than that of the low-frequency ultrasonic wave. The thickness of the package is 50 μm-150 μm, and the frequency value of the low-frequency ultrasonic wave is 8 Mhz-2 Mhz. By adjusting the thickness of the package, the frequency value of the low-frequency ultrasonic wave emitted by the ultrasonic sensor can be more effectively adjusted to meet the frequency design requirement of the low-frequency ultrasonic wave.

[0022] In a possible implementation, the at least two biological characteristic signals include at least one of a fingerprint signal, a heart rate signal, a blood oxygen signal, a blood pressure signal, and a respiration rate signal.

[0023] The second aspect of the embodiment of the present application provides a sensor module, including a control chip and the ultrasonic sensor of any one of the above.

[0024] The third aspect of the embodiment of the present application provides an electronic device, including a cover plate and the ultrasonic sensor of any one of the above, the ultrasonic sensor is fixed to a side of the cover plate, the chip of the ultrasonic sensor is located at an end of the ultrasonic sensor away from the cover plate, or the chip of the ultrasonic sensor is connected to the cover plate.

[0025] In a possible implementation, a second adhesive layer is further included, and the ultrasonic sensor is fixed to the cover plate via the second adhesive layer, thereby facilitating assembly of the ultrasonic sensor within the device.

[0026] A fourth aspect of an embodiment of the present application provides a vehicle, comprising a cover plate and any one of the above-mentioned ultrasonic sensors, wherein the ultrasonic sensor is fixed to one side of the cover plate, the chip of the ultrasonic sensor is located at an end of the ultrasonic sensor facing away from the cover plate, or the chip of the ultrasonic sensor is connected to the cover plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A cross-sectional schematic diagram of an ultrasonic sensor provided in an embodiment of the present application being assembled in a device;

[0028] Figure 2 A cross-sectional schematic diagram of a fingerprint ultrasonic sensor in the related art assembled in a device;

[0029] Figure 3 A schematic cross-sectional view of an ultrasonic sensor according to an embodiment of the present application;

[0030] Figure 4 for Figure 3 A magnified schematic diagram of the partial cross-sectional structure of the ultrasonic sensor at the chip and redistribution expansion layer;

[0031] Figure 5 for Figure 3 Schematic diagram of the curve showing the change of the sound pressure of the ultrasonic sensor with the thickness of the chip substrate;

[0032] Figure 6 A schematic structural diagram of another ultrasonic sensor provided in an embodiment of the present application;

[0033] Figure 7 for Figure 6 Schematic diagram of a curve showing the change of the sound pressure of the ultrasonic sensor with the thickness of the package;

[0034] Figure 8 for Figure 3 A schematic diagram of an assembly cross-sectional structure of an ultrasonic sensor and a device cover;

[0035] Figure 9 for Figure 8 Schematic diagram of loading the ultrasonic sensor excitation signal;

[0036] Figure 10 for Figure 8 Schematic diagram of the circuit connection of the ultrasonic sensor receiving the echo signal;

[0037] Figure 11 for Figure 3Another assembly cross-sectional structure diagram of the ultrasonic sensor and the device cover plate in the embodiment of the present application;

[0038] Figure 12 For Figure 11 A loading diagram of an ultrasonic sensor excitation signal in the embodiment of the present application;

[0039] Figure 13 For Figure 3 A detection method flow diagram of the ultrasonic sensor in the embodiment of the present application.

[0040] Explanation of reference signs:

[0041] 100 - ultrasonic sensor;

[0042] 10 - chip;

[0043] 11 - chip substrate; 111 - first pixel electrode;

[0044] 12 - package;

[0045] 20 - piezoelectric resonant unit;

[0046] 201 - piezoelectric layer group;

[0047] 21 - redistribution layer; 211 - second pixel electrode; 212 - connection trace;

[0048] 22 - piezoelectric layer;

[0049] 23 - electrode layer;

[0050] 202 - protective layer group;

[0051] 24 - first adhesive layer;

[0052] 25 - protective layer;

[0053] 200 - cover plate; 200a - first surface; 200b - second surface;

[0054] 300 - second adhesive layer. DETAILED DESCRIPTION

[0055] The terms used in the embodiment part of the present application are only used for explaining the specific embodiments of the present application, and are not intended to limit the present application.

[0056] The embodiment of the present application provides an ultrasonic sensor capable of transmitting and receiving ultrasonic wave signals, which can be used to realize detection of biological feature information, so as to achieve the purposes of user identity authentication recognition, unlocking, safe payment, health tracking and detection, etc. The biological feature information can include but is not limited to fingerprint, palm print, heart rate, blood pressure, blood oxygen, imaging of biological shallow tissue (such as eyes, ears, nose), etc.

[0057] The ultrasonic sensor can be used in electronic devices to endow the electronic devices with biometric detection and identification functions, which can include but are not limited to mobile phones, tablet personal computers, notebook computers, desktop computers, game devices, ultra-mobile personal computers (UMPCs), netbooks, point of sale (POS) machines, personal digital assistants (PDAs), in-vehicle electronic devices, wearable devices, automatic teller machines, electronic databases, and the like.

[0058] For example, in the scenario where the ultrasonic sensor is applied to a wearable device, the wearable device can be a device that does not need to be associated with a smart device such as a mobile phone and can independently realize complete or partial functions. For example, the wearable device can be a smart watch, smart glasses, an augmented reality (AR) device, a virtual reality (VR) device, a mixed reality (MR) device, an extended reality (XR) device, or the like. Alternatively, the wearable device can be an electronic device that needs to be used in cooperation with a smart device such as a mobile phone. For example, the wearable device can be a smart bracelet, smart jewelry, or the like for realizing various biometric detections.

[0059] The ultrasonic sensor can also be used in lock devices, for example, in door locks, cabinet locks, and the like.

[0060] The ultrasonic sensor can also be used in vehicles, for example, in smart cars. For example, in some examples, the ultrasonic sensor can be arranged on a door handle of a car. Taking the detection and identification of fingerprints as an example, when a driver holds the handle, the ultrasonic sensor can realize fingerprint identification and authentication of identity, thereby realizing the operation of opening the door, avoiding the cumbersome operation of carrying a car key. In some examples, the ultrasonic sensor can also be arranged on a start button. When the driver presses the start button, the ultrasonic sensor can identify and authenticate the fingerprint, thereby realizing the engine ignition operation to start the car and improving the safety of the vehicle.

[0061] The ultrasonic sensor can be connected with a control unit of the vehicle. The ultrasonic sensor can detect the biological feature information (e.g., fingerprint information) and implement storage, comparison and identification of the biological feature information. Alternatively, the ultrasonic sensor can transmit the biological feature information to the control unit, and the control unit can implement storage, comparison and identification of the biological feature information. In some examples, fingerprint information of multiple drivers can be input through the ultrasonic sensor and stored in the control unit or the ultrasonic sensor. The control unit can also store setting habit information of the multiple drivers during driving. The setting habit information can be cabin setting information, such as seat positioning setting information, rearview mirror angle setting information, etc. When the vehicle is used, the ultrasonic sensor arranged on the door handle, start button or other position of the vehicle wheel can identify and authenticate the driver, so that the control unit can load the setting habit information of the corresponding driver, avoid repeated adjustment, and improve the use experience.

[0062] In some examples, the ultrasonic sensor can be applied to the various devices described above alone. Alternatively, in some examples, the ultrasonic sensor can be integrated with a chip to form an ultrasonic sensor module, which can be applied to the various devices described above, for example, the ultrasonic sensor module can include an ultrasonic sensor and a control chip. The ultrasonic sensor and the control chip are electrically connected. The control chip can be used to implement timing control, image processing and comparison identification, etc. The control chip can be electrically connected with a control unit of the device.

[0063] Figure 1 A cross-sectional view of an ultrasonic sensor provided by an embodiment of the present application is assembled in a device.

[0064] The ultrasonic sensor 100 can be integrated inside the electronic device, the vehicle or other devices described above. Taking the case of the ultrasonic sensor 100 arranged in an electronic device as an example, referring to FIG. 1, the electronic device can include a housing (not shown in the figure) and a cover plate 200. The cover plate 200 is arranged on the housing to form an accommodation space. The ultrasonic sensor 100 can be arranged in the accommodation space. Figure 1

[0065] The cover plate 200 can be a light-transmitting structure or a non-light-transmitting structure. The cover plate 200 can be formed of a single material, for example, the cover plate 200 can be a plate-shaped structure formed of glass, metal or polymer. Alternatively, the cover plate 200 can be a multi-layer film structure, for example, the cover plate 200 can be a display screen of the electronic device formed by stacking multiple film layers.

[0066] In the embodiment of the present application, the thickness direction of the cover plate 200 is the x direction, as shown in FIG. 1. Figure 1 ​The cover plate 200 can include two surfaces opposite in the thickness direction, for example, a first surface 200a and a second surface 200b. The first surface 200a can be towards the interior of the device, and the second surface 200b can have a detection area for placing a detection site (such as a finger 400, etc.) to monitor biometric information.

[0067] For example, the ultrasonic sensor 100 can be mounted on the first surface 200a of the cover plate 200. When biometric detection and recognition are required, for example, see Figure 1 For example, when the detection site is a finger 400, and the ultrasonic sensor 100 is used to detect fingerprints, heart rate, etc., the finger 400 can be placed on the second surface 200b of the cover plate 200. The ultrasonic sensor 100 can emit ultrasonic signals, which pass through the cover plate 200 and reach the finger 400. The finger 400 can reflect part of the ultrasonic signals, and the reflected ultrasonic signals can be received by the ultrasonic sensor 100 after passing through the cover plate 200. Because the ridge valley distribution of different fingerprints is different, the reflection of ultrasonic signals is also different. Correspondingly, the ultrasonic signals can pass through the epidermis to reach the subcutaneous tissue, and changes in heart rate can also affect the reflection of ultrasonic signals. Therefore, the ultrasonic sensor can obtain biometric information such as fingerprint information and heart rate information based on the reflected ultrasonic signals, thereby enabling fingerprint detection based on fingerprint information and heart rate detection based on heart rate information.

[0068] It can be understood that for different biometric detection, the required ultrasonic frequency is different to obtain good accuracy. For example, in the detection of epidermal structures such as fingerprints and palm prints, the required ultrasonic frequency is relatively high (high-frequency ultrasonic waves), and the ultrasonic penetration is relatively small, so that it is more reflected by the epidermis. In the detection of subcutaneous tissue related to heart rate, blood pressure, and blood oxygen, the required ultrasonic frequency is relatively low (low-frequency ultrasonic waves), and the ultrasonic penetration is relatively large, so that it can pass through the epidermis to reach the subcutaneous tissue.

[0069] Figure 2 A cross-sectional view of a fingerprint ultrasonic sensor in the related art mounted in a device.

[0070] Most ultrasonic sensors for fingerprint detection use a sandwich type single piezoelectric structure, for example, see Figure 2As shown, the fingerprint ultrasonic sensor can include a chip 110, one side of the chip 110 can be sequentially stacked with a first electrode layer 120, a piezoelectric material layer 130, a second electrode layer 140 and a protective layer 150, and the other side of the chip 110 can be fixed with the cover plate 210 through the adhesive layer 301. Among them, the piezoelectric material layer 130 can be composed of piezoelectric material, the second electrode layer 140 can couple the electrical signal to the piezoelectric material layer 130, and the piezoelectric material of the piezoelectric material layer 130 deforms and vibrates under the voltage excitation through the inverse piezoelectric effect, thereby emitting ultrasonic waves. The ultrasonic waves reflected by the fingerprint reach the piezoelectric material layer 130, causing the piezoelectric material layer 130 to deform and vibrate, and through the piezoelectric effect, corresponding electrical signals are generated, which can be conducted to the chip through the first electrode layer 120 to form fingerprint information, thereby realizing the detection and identification of fingerprints.

[0071] The fingerprint ultrasonic sensor is used to realize the detection of fingerprints, and the transmitted ultrasonic waves are mostly high-frequency ultrasonic waves, which cannot well detect the biological characteristic performance related to subcutaneous tissue, such as heart rate, blood pressure, blood oxygen, etc., and the function is relatively single. In some devices with fingerprint identification, heart rate detection and other detection and identification needs of multiple biological characteristics, multiple sensors are usually integrated in the device to respectively realize the detection of multiple biological characteristic information, and the structure is relatively complex and the cost is relatively high. Therefore, there is an urgent need for an ultrasonic sensor capable of realizing multiple biological characteristic detection functions.

[0072] Based on this, the embodiment of the present application provides an ultrasonic sensor, which comprises a chip and a piezoelectric resonant unit arranged on the chip, the piezoelectric layer group of the piezoelectric resonant unit generates ultrasonic waves, the ultrasonic waves propagate between the layers of the chip and the piezoelectric resonant unit to generate resonance superposition, the chip substrate and the packaging material of the packaging piece are different, the resonance superposition effect of the chip substrate and the packaging piece on the ultrasonic waves is different, at least two ultrasonic wave signals of different frequencies can be formed, and the chip can obtain at least two biological characteristic information, that is, the detection of multiple biological characteristic information can be realized by one ultrasonic sensor, the function of the ultrasonic sensor is enriched, the needs of multiple application scenarios are met, and the sensor structure in the device is reduced, the structure design is simplified, and the cost is reduced.

[0073] Moreover, by adjusting the thickness of each layer in the piezoelectric resonant unit, the thickness of the chip substrate and the thickness of the packaging piece, the frequency value of the ultrasonic wave signal can be designed, the ultrasonic wave signal of the target frequency can be obtained, and the ultrasonic wave of the target frequency can be ensured to have strong intensity and optimal efficiency, the frequency of the ultrasonic wave signal can be designed, different detection functions can be realized, and thus the needs of different application scenarios can be matched, and the applicable scenarios of the ultrasonic sensor are enriched.

[0074] Figure 3A cross-sectional structure diagram of an ultrasonic sensor is provided for an embodiment of the present application.

[0075] Referring to Figure 3 As shown, the ultrasonic sensor 100 includes a chip 10, which can include a chip substrate 11 and a packaging member 12, the packaging member 12 can be wrapped on the outer periphery of the chip substrate 11, and the chip substrate 11, the circuit and electronic devices on the chip substrate 11, etc. play a packaging protection role, for example, pixel circuit electrodes, analog-digital module circuit units, etc. can be provided on the substrate chip 10.

[0076] The molding material of the chip substrate 11 is different from the molding material of the packaging member 12, it can be understood that because the molding material of the chip substrate 11 is different from the molding material of the packaging member 12, the speed of ultrasonic signal propagation in the chip substrate 11 and the packaging member 12 is different, and the reflection, absorption, etc. of the chip substrate 11 and the packaging member 12 to the ultrasonic wave is also different.

[0077] For example, the molding material of the chip substrate 11 can include one or more of glass, silicon wafer, polyimide (PI), polyethylene terephthalate (PET), etc.

[0078] The molding material of the packaging member 12 can include plastic, resin, etc., for example, the molding material of the packaging member 12 can be exopy.

[0079] The ultrasonic sensor 100 further includes a piezoelectric resonant unit 20, which is arranged on one side of the chip 10, that is, the piezoelectric resonant unit 20 is arranged in a stack with the chip 10, and the stacking direction can be consistent with the thickness direction of the cover plate 200, such as the x direction as shown in Figure 3 The chip 10 has two opposite surfaces along the stacking direction (x direction), such as the third surface and the fourth surface, for example, the piezoelectric resonant unit 20 can be located on the third surface of the chip 10.

[0080] The piezoelectric resonant unit 20 can include a piezoelectric layer group 201 and a protective layer group 202, which are arranged in a stack along the stacking direction, and the protective layer group 202 can play a role of isolation and protection for the piezoelectric layer group 201 to ensure the stability of the piezoelectric resonant unit and the entire ultrasonic sensor.

[0081] The piezoelectric layer group 201 can be a layer group structure formed by a plurality of film layers stacked in a stacking direction. The piezoelectric layer group 201 can generate ultrasonic waves. For example, the piezoelectric layer group 201 can include a piezoelectric layer 22 and an electrode layer 23. The piezoelectric layer 22 can deform and vibrate under the voltage excitation of the electrode layer 23 to form ultrasonic waves. The ultrasonic waves can propagate toward or away from the chip 10 along the stacking direction. The film layers above the piezoelectric layer 22 (on the side away from the chip 10 along the stacking direction) and below the piezoelectric layer 22 (on the side facing the chip 10 along the stacking direction) in the piezoelectric resonant unit 20, and the chip 10 can form resonance, and then the resonance of the ultrasonic waves is superimposed, which is beneficial to improve the transmission efficiency and intensity of the ultrasonic wave signal.

[0082] Due to the difference in materials between the chip substrate 11 and the package 12, the resonance superposition effects of the chip substrate 11 and the package 12 are different, so that the ultrasonic waves generated by the piezoelectric layer 22 can be superimposed by the resonance of the chip 10, the piezoelectric layer group 201 and the protective layer group 202, and at least two ultrasonic wave signals of different frequencies can be formed.

[0083] The at least two ultrasonic wave signals of different frequencies can be transmitted to a detection site (such as a finger, etc.), and the different frequency ultrasonic wave signals reflected therefrom can be transmitted to the piezoelectric layer group 201. The piezoelectric layer group 201 receives the different frequency ultrasonic wave signals reflected therefrom and converts the different frequency ultrasonic wave signals into electrical signals, respectively, and transmits the electrical signals to the chip 10. The chip 10 can obtain at least two biological feature information according to the electrical signals, thereby realizing the detection of multiple biological feature information and enriching the functions of the ultrasonic sensor 100. Thus, using one ultrasonic sensor 100 can endow the device with multiple biological feature information detection and recognition functions, meet the needs of multiple application scenarios, reduce the sensor structure in the device, simplify the structural layout design of the device, and reduce the cost of the device.

[0084] The frequency value of the ultrasonic wave signal transmitted by the ultrasonic sensor 100 can be designed. For example, the at least two ultrasonic wave signals of different frequencies transmitted by the ultrasonic sensor 100 include a preset frequency ultrasonic wave. The preset frequency ultrasonic wave can be a working frequency (i.e., a target frequency) required to realize one of the biological feature detections.

[0085] It should be noted that the at least two ultrasonic wave signals of different frequencies transmitted by the ultrasonic sensor 100 can include a low-frequency ultrasonic wave signal and a high-frequency ultrasonic wave signal. The frequency value of the high-frequency ultrasonic wave signal can be higher than that of the low-frequency ultrasonic wave signal. When the frequency of the ultrasonic wave signal of the ultrasonic sensor 100 is designed, the resonance superposition effects of the piezoelectric resonant unit 20 and the chip 10 on the low-frequency ultrasonic wave signal and the high-frequency ultrasonic wave signal are consistent. The preset frequency ultrasonic wave can be any one of the low-frequency ultrasonic wave signal and the high-frequency ultrasonic wave signal.

[0086] The frequency value of the preset frequency ultrasonic wave can be selected according to actual needs. For example, when the main function of the ultrasonic sensor 100 is to realize fingerprint detection and identification, the preset frequency ultrasonic wave can be one of high-frequency ultrasonic waves, for example, the frequency of the preset frequency ultrasonic wave can be any frequency in 8Mhz-25Mhz. For example, when the main function of the ultrasonic sensor 100 is to realize heart rate detection, the preset frequency ultrasonic wave can be one of low-frequency ultrasonic waves, for example, the frequency of the preset frequency ultrasonic wave can be any frequency in 5Mhz-10Mhz.

[0087] In the embodiment of the present application, the thickness of the film layer refers to the thickness in the stacking direction, for example, each layer in the piezoelectric resonant unit 20 has a corresponding first preset thickness, that is, each layer in the piezoelectric resonant unit 20 has a corresponding first preset thickness. The chip substrate 11 has a second preset thickness, and the packaging member 12 has a third preset thickness. The first preset thickness, the second preset thickness and the third preset thickness can be designed according to the frequency value of the preset frequency ultrasonic wave. That is, the thickness of each layer in the piezoelectric resonant unit 20, the thickness of the chip substrate 11 and the thickness of the packaging member 12 can be designed to realize the frequency value design of the ultrasonic wave signal emitted by the ultrasonic sensor 100, so as to obtain the ultrasonic wave signal of the target frequency (i.e. the preset frequency ultrasonic wave), and ensure that the ultrasonic wave signal of the target frequency has strong intensity and optimal efficiency, realize the designable frequency of the ultrasonic wave signal, so as to realize different detection functions, and can match the needs of different application scenarios, and enrich the applicable scenarios of the ultrasonic sensor 100.

[0088] For example, low-frequency ultrasonic waves and high-frequency ultrasonic waves can match different application scenarios to enable the ultrasonic sensor 100 to realize different detection functions. For example, a high-frequency ultrasonic signal can be reflected by a fingerprint on the epidermis layer, and the reflected high-frequency ultrasonic signal is received by the piezoelectric layer group and converted into an electric signal. The chip can obtain a fingerprint signal according to the electric signal to realize detection and identification of the fingerprint on the epidermis layer.

[0089] The low-frequency ultrasonic signal can pass through the epidermis of the finger and be reflected by the subcutaneous tissue, and the reflected low-frequency ultrasonic signal is received by the piezoelectric layer group and converted into an electric signal. The chip can obtain biological characteristics related to the subcutaneous tissue, such as heart rate, blood oxygen, blood pressure, etc. according to the electric signal. Alternatively, the low-frequency ultrasonic signal can pass through the epidermis of the finger and be reflected by the dermis layer to obtain a dermis layer image signal, etc., to realize detection of the dermis layer image.

[0090] The protective layer group 202 can include a first adhesive layer 24 and a protective layer 25. The protective layer 25 serves to protect the piezoelectric layer group 201, and the first adhesive layer 24 is used to fix the protective layer 25 to the piezoelectric layer group. The first adhesive layer 24 is located between the protective layer 25 and the piezoelectric layer group 201, and the protective layer 25 is arranged on the side of the piezoelectric layer group 201 away from the chip 10 through the first adhesive layer 24. The protective layer group 202 has a two-layer structure, which increases the number of layers of the piezoelectric resonant unit 20, thereby enhancing the resonance and superposition effect of the ultrasonic waves, improving the efficiency and intensity of the ultrasonic signal, and increasing the flexibility of the frequency value design of the ultrasonic signal.

[0091] When the ultrasonic sensor 100 is formed, the protective layer 25 can be directly bonded to the piezoelectric layer group 201 through the first adhesive layer 24. Compared with forming an adhesive protective layer 25 on the piezoelectric layer group 201 by deposition or other methods, directly bonding the protective layer 25 to the piezoelectric layer group 201 through the first adhesive layer 24 is more convenient, simplifies the forming process, and helps to reduce the production cost and improve the production efficiency.

[0092] For example, the protective layer 25 and the first adhesive layer 24 can be made of different materials. For example, the protective layer 25 can be made of a material with relatively high hardness, and the first adhesive layer 24 can be made of a material with relatively low hardness and relatively high adhesion. The materials and thicknesses of the protective layer 25 and the first adhesive layer 24 can affect the resonance and superposition effect of the ultrasonic waves. Adjusting the materials and thicknesses of the protective layer 25 and the first adhesive layer 24 can change the resonance and superposition effect, thereby improving the efficiency and intensity of the ultrasonic signal and further increasing the flexibility of the frequency value design of the ultrasonic signal.

[0093] In some examples, the first adhesive layer 24 and the protective layer 25 can be integrally formed into an integrated structure. The first adhesive layer 24 can be located on one side of the protective layer 25, so that the integrated structure has the properties of a tape, with one side being the first adhesive layer 24 and the other side being the protective layer 25. When the ultrasonic sensor 100 is formed, the integrated structure can be directly bonded to the piezoelectric layer group 201.

[0094] Of course, in some examples, the first adhesive layer 24 and the protective layer 25 can also be two independent structural members. When the ultrasonic sensor 100 is formed, the first adhesive layer 24 can be bonded to one of the protective layer 25 or the piezoelectric layer group 201, and then the protective layer 25 and the piezoelectric layer group 201 can be bonded.

[0095] Continuing to refer to Figure 3As shown, the piezoelectric layer group 201 includes a stacked piezoelectric layer 22 and an electrode layer 23. The molding material of the piezoelectric layer 22 includes a piezoelectric material. The piezoelectric material is a crystalline material that generates a voltage between its two end surfaces when subjected to pressure.

[0096] For example, the molding material of the piezoelectric layer 22 may include, but is not limited to, organic polymer piezoelectric materials such as polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene, or inorganic piezoelectric materials such as lead zirconate titanate piezoelectric ceramics (PZT) and aluminum nitride (AlN).

[0097] The molding material of the electrode layer 23 may include a conductive material, for example, a metal material, such as a film layer formed of a metal material such as silver, copper, etc.

[0098] The electrode layer 23 applies a voltage to the piezoelectric layer 22. Upon receiving the voltage, the piezoelectric layer 22 deforms and vibrates through the inverse piezoelectric effect, thereby generating ultrasonic waves. Conversely, through the piezoelectric effect, the piezoelectric layer 22 receives ultrasonic waves and converts them into electrical signals, which are then transmitted to the chip 10 to obtain biometric information.

[0099] Figure 4 for Figure 3 A magnified schematic diagram of the local cross-sectional structure of the ultrasonic sensor at the chip and redistribution expansion layer.

[0100] See also Figure 4 As shown, the chip 10 may further include a plurality of first pixel electrodes 111 , and an array of the plurality of first pixel electrodes 111 is distributed on one surface of the chip substrate 11 . It is understandable that the plurality of first pixel electrodes 111 may be located on a surface on the same side of the chip substrate 11 and the third surface of the chip 10 .

[0101] It should be noted that in ultrasonic sensors in related technologies, the electrical signal converted by the piezoelectric layer is transmitted to the chip's first pixel electrode to enable biometric information recognition. The size of the ultrasonic sensor's recognition area is closely related to the area of ​​the first pixel electrode array on the chip. If the chip substrate and the multiple first pixel electrode arrays on the chip substrate are relatively small, the recognition area will be small, making it difficult to obtain sufficient biometric points, which will significantly weaken the recognition function. To improve the detection and recognition capabilities of the ultrasonic sensor, the recognition area must be increased, which also requires increasing the chip substrate area, which will increase costs.

[0102] Therefore, in the embodiments of this application, seeFigure 4 As shown, the piezoelectric layer group can further include a redistribution layer 21, which is located between the third surface of the chip 10 and the piezoelectric layer 22 (see FIG. 2B). Figure 3 As shown, the redistribution layer 21, the piezoelectric layer 22, the electrode layer 23, the first adhesive layer 24, and the protective layer 25 are sequentially stacked on the third surface of the chip 10.

[0103] Continuing to refer to FIG. 2B, Figure 4 As shown, the redistribution layer 21 is disposed on the third surface of the chip 10, and covers the chip substrate 11 and the package 12. The redistribution layer 21 covers the plurality of first pixel electrodes 111 on the chip substrate 11.

[0104] The ultrasonic sensor 100 can further include a plurality of second pixel electrodes 211, which are arrayed on a side of the redistribution layer 21 opposite to the chip 10, i.e., between the redistribution layer 21 and the piezoelectric layer 22. The piezoelectric layer 22 can cover the plurality of second pixel electrodes 211.

[0105] The plurality of first pixel electrodes 111 and the plurality of second pixel electrodes 211 can be electrically connected. For example, the redistribution layer 21 can include a plurality of connection traces 212. The plurality of first pixel electrodes 111 can be connected to the plurality of second pixel electrodes 211 one by one through the connection traces 212, to realize electrical signal transmission between the first pixel electrodes 111 and the second pixel electrodes 211.

[0106] For example, the second pixel electrodes 211 can receive electrical signals from the piezoelectric layer, and can realize point-to-line image restoration through pixelization, to obtain image information of a biological feature and transmit the image information to the first pixel electrodes 111 of the chip 10.

[0107] The first pixel electrodes 111 and the second pixel electrodes 211 can be formed of conductive materials. The first pixel electrodes 111 and the second pixel electrodes 211 can be formed of the same material or different materials. For example, the first pixel electrodes 111 and the second pixel electrodes 211 can be formed of indium tin oxide (ITO), aluminum (Al), copper (Cu), or other conductive materials.

[0108] The redistribution layer 21 covers one side of the chip substrate 11 and the package 12. The redistribution layer 21 can have a larger area than the chip substrate 11, so that the array area of the second pixel electrode 211 can be larger than the array area of the first pixel electrode 111. The electrical signal can be fanned out from the first pixel electrode 111 array in the chip substrate 11 to the second pixel electrode 211 array with a larger area, decoupling the constraint between the chip substrate 11 area and the identification area, and increasing the area of the redistribution layer 21 and the second pixel electrode 211 array can achieve the purpose of increasing the identification area. Therefore, the identification area is increased without increasing the size of the chip substrate 11 and the first pixel electrode 111 array, and the cost increase is reduced.

[0109] By increasing the area of the redistribution layer 21 and the second pixel electrode 211 array, the ultrasonic sensor can have a larger identification area, which can improve the detection sensitivity and accuracy of the ultrasonic sensor, facilitate the realization of “one-key input” of fingerprints and the like, and also facilitate the optimization of the use experience in the scene of unlocking and the like through fingerprints and the like.

[0110] The following describes an example of designing the frequency value of the ultrasonic wave signal emitted by the ultrasonic sensor 100. It should be noted that the thickness and material of each structural film layer in the ultrasonic sensor will affect the resonance superposition effect of the ultrasonic wave, and then affect the frequency value of the ultrasonic wave signal. For example, the thickness of each structural film layer can be adjusted to design the frequency value of the ultrasonic wave signal, so that the ultrasonic sensor can emit an ultrasonic wave signal with a preset frequency (i.e., an ultrasonic wave signal with a target frequency).

[0111] In the piezoelectric resonant unit 20, the thickness of each layer and the preset frequency ultrasonic wave can satisfy 0.1≤∑(h i / λ i )≤0.4, h i is the first preset thickness of each layer in the piezoelectric resonant unit 20, and λ i is the wavelength of the preset frequency ultrasonic wave in each layer of the piezoelectric resonant unit 20.

[0112] Referring back to Figure 3As shown, the thickness of the redistribution expansion layer 21 can be h1, the wavelength of the preset frequency ultrasonic wave in the redistribution expansion layer 21 can be λ1, the thickness of the piezoelectric layer 22 can be h2, the wavelength of the preset frequency ultrasonic wave in the piezoelectric layer 22 can be λ2, the thickness of the electrode layer 23 can be h3, the wavelength of the preset frequency ultrasonic wave in the redistribution expansion layer 21 can be λ3, the thickness of the first adhesive layer 24 can be h4, the wavelength of the preset frequency ultrasonic wave in the first adhesive layer 24 can be λ4, the thickness of the protective layer 25 can be h5, and the wavelength of the preset frequency ultrasonic wave in the protective layer 25 can be λ5. The range of h1 / λ1+h2 / λ2+h3 / λ3+h4 / λ4+h5 / λ5 is 0.1-0.4. The ultrasonic sensor 100 has better resonance superposition effect of the ultrasonic wave, which further improves the efficiency of the ultrasonic sensor 100 and enhances the strength of the emitted ultrasonic signal, thereby improving the detection and recognition performance of the ultrasonic sensor 100.

[0113] In the formula, the wavelength of the preset frequency ultrasonic wave in each film layer can be obtained by λ=v / f, where λ is the wavelength, v is the propagation speed of the preset frequency ultrasonic wave in the film layer, and f is the preset frequency.

[0114] It can be understood that the superposition of the ultrasonic wave on the theoretically perfect acoustic path may, while being designed to have a target frequency (i.e., the preset frequency), deviate from the design. In actual implementation, the selection can be made according to actual requirements.

[0115] For example, the piezoelectric resonant unit 20 can satisfy ∑(h i / λ i )=1 / 4, such as h1 / λ1+h2 / λ2+h3 / λ3+h4 / λ4+h5 / λ5=1 / 4, which has a more excellent resonance superposition effect, obtains better efficiency and stronger strength, and further improves the performance of the ultrasonic sensor 100.

[0116] The relationship between the thickness of each layer in the piezoelectric resonant unit 20, the thickness of the chip substrate 11, and the thickness of the packaging member 12 and the preset frequency ultrasonic wave can satisfy 0.3≤∑(h i / λ i )+(h a / λ a )≤0.7, where h a is the second preset thickness of the chip substrate 11 or the third preset thickness of the packaging member 12, and λ a is the wavelength of the preset frequency ultrasonic wave in the chip substrate 11 or the packaging member 12. For example, h a may be the thickness of the chip substrate 11, λ a may be the wavelength of the preset frequency ultrasonic wave in the chip substrate 11, h1 / λ1+h2 / λ2+h3 / λ3+h4 / λ4+h5 / λ5+ha / λ a The range of is 0.3 to 0.7, which is beneficial to further enhance the resonance superposition effect, thereby further enhancing the efficiency of the ultrasonic sensor 100 and the intensity of the ultrasonic wave.

[0117] It should be noted that the second preset thickness of the chip substrate 11 and the third preset thickness of the package 12 will affect the frequency value of the ultrasonic signal. For example, in some examples, the thicknesses of the chip substrate 11 and the package 12 can be adjusted as a whole to achieve the design of the frequency value. The second preset thickness of the chip substrate 11 can be consistent with the third preset thickness of the package 12. The above h a It can be any one of the second preset thickness of the chip substrate 11 and the third preset thickness of the package 12. In some examples, the thickness of the chip substrate 11 or the package 12 can also be adjusted independently to achieve the design of the frequency value. a The preset thickness of the chip substrate 11 or the package 12 may be adjusted. For example, the frequency value can be adjusted by adjusting the thickness of the package 12. a The package 12 may have a third predetermined thickness.

[0118] For example, the ultrasonic sensor 100 may satisfy Σ(h i / λ i )+(h a / λ a )=1 / 2, as mentioned above h1 / λ1+h2 / λ2+h3 / λ3+h4 / λ4+h5 / λ5+h a / λ a =1 / 2. This achieves a more excellent resonance superposition effect, obtains better efficiency and stronger strength, and further helps to improve the performance of the ultrasonic sensor 100.

[0119] It should be noted that the frequency of the ultrasonic signal can be adjusted by adjusting the thickness of any one or several of the layers in the piezoelectric resonant unit 20, the chip substrate 11 and the package 12. That is to say, the frequency value of the ultrasonic signal emitted by the ultrasonic sensor 100 can be adjusted by adjusting the thickness of any one or several of the chip substrate 11, the package 12, the redistribution expansion layer 21, the piezoelectric layer 22, the electrode layer 23, the first adhesive layer 24 and the protective layer 25.

[0120] For example, the frequency of the preset ultrasonic wave can be adjusted by adjusting the thickness of the chip substrate 11 and the package 12 as a whole, so as to obtain ultrasonic waves of different frequencies to match the requirements of different application scenarios.

[0121] For example, in some examples, the chip substrate 11 and the package 12 can have the same thickness, so that the chip substrate 11 and the package 12 can form a chip base 10a (see FIG. 10) having the same thickness. By adjusting the thickness of the chip substrate 11 and the package 12 as a whole, the frequency value and the intensity of the preset frequency ultrasonic wave can be adjusted and designed. Figure 3

[0122] Figure 5 For example, in some examples, the chip substrate 11 and the package 12 can have the same thickness, so that the chip substrate 11 and the package 12 can form a chip base 10a (see FIG. 10) having the same thickness. By adjusting the thickness of the chip substrate 11 and the package 12 as a whole, the frequency value and the intensity of the preset frequency ultrasonic wave can be adjusted and designed. Figure 3

[0123] As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear. Figure 5 As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear.

[0124] Figure 5 As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear.

[0125] As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear. Figure 5 As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear.

[0126] As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear.

[0127] Figure 5 As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear. Figure 5 As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear. As shown in FIG. 9, by changing the thickness of the chip base 10a, the sound pressure regularity of the ultrasonic wave emitted by the ultrasonic sensor under the same voltage excitation is shown. As shown in FIG. 9, within the range of 25Mhz, multiple frequency peaks will appear.​​​

[0128] Exemplarily, the preset frequency of the ultrasonic wave can be adjusted by adjusting the thickness of the package 12 to obtain ultrasonic waves of different frequencies to match the requirements of different application scenarios.

[0129] Figure 6 Another structural schematic diagram of an ultrasonic sensor is provided for the embodiments of the present application.

[0130] The thickness of the package 12 is changed. In one possible example, see Figure 6 Exemplarily, the thickness of the package 12 can be inconsistent with the thickness of the chip substrate 11. Of course, in some other examples, the thickness of the package 12 can also be consistent with the thickness of the chip substrate 11.

[0131] Figure 7 The ultrasonic sensor in Figure 6 A curve diagram of the sound pressure of the ultrasonic sensor in

[0132] See Figure 7 Exemplarily, by changing the thickness of the package 12, the frequency value of the preset frequency ultrasonic wave changes after the same voltage excitation is applied. The thickness of the package 12 is negatively correlated with the frequency of the preset frequency ultrasonic wave. With the increase of the thickness of the package 12, the frequency value of the preset frequency ultrasonic wave decreases. The frequency of the preset frequency ultrasonic wave is designed to match the requirements of different application scenarios, improve the detection performance, and expand the applicable range.

[0133] In which, see Figure 7 Exemplarily, as an example of the ultrasonic wave with a frequency range of 1Mhz-8Mhz as a low-frequency ultrasonic wave, the thickness of the package 12 is changed. The maximum value of the sound pressure of the high-frequency ultrasonic wave remains basically unchanged. For the low-frequency ultrasonic wave, the frequency value and the sound pressure value of the low-frequency ultrasonic wave are effectively adjusted. That is, by adjusting the thickness of the package 12, the frequency value of the low-frequency ultrasonic wave can be more effectively adjusted and designed to meet the frequency design requirements of the low-frequency ultrasonic wave.

[0134] Exemplarily, the thickness of the package 12 can be changed in the range of 50μm-150μm (including the boundary value), and the frequency value of the low-frequency ultrasonic wave can be changed in the range of 8Mhz-2Mhz (including the boundary value).

[0135] For example, see Figure 7 Exemplarily, the thickness of the package 12 can be changed in the range of 50μm-150μm (including the boundary value), and the frequency value of the low-frequency ultrasonic wave can be changed in the range of 8Mhz-2Mhz (including the boundary value). Figure 7S1: E140+Si120(3+1) curve, S2: E+Si120(3+1) curve, S3: E100+Si120(3+1) curve are the sound pressure curves of the package 12 with thickness of 140 μm, 120 μm, 100 μm respectively, as the thickness of the package 12 increases from 100 μm to 140 μm, the frequency value of the low frequency ultrasonic wave changes from 8.6 Mhz to 6.5 Mhz.

[0136] The following examples illustrate the assembly application of the ultrasonic sensor in electronic devices, vehicles and other devices.

[0137] Figure 8 An assembly cross-sectional structure diagram of the ultrasonic sensor and the device cover plate in Figure 3

[0138] When the ultrasonic sensor 100 is applied in a device, the ultrasonic sensor 100 can be fixedly bonded with the cover plate 200, for example. Figure 8 As shown in

[0139] The second bonding layer 300 can be an acoustic / mechanical coupling layer, the second bonding layer 300 can be a homogeneous film layer formed by a bonding material, or the second bonding layer 300 can also be a composite film layer formed by multiple layers.

[0140] In some examples, the ultrasonic sensor 100 can be fixed with the cover plate 200 in a direct bonding manner. As shown in Figure 8 The side of the protective layer 25 of the ultrasonic sensor 100 facing away from the chip 10 can be bonded and fixed with the first surface of the cover plate 200 through the second bonding layer 300.

[0141] Figure 9 An assembly cross-sectional structure diagram of the ultrasonic sensor and the device cover plate in Figure 8

[0142] As shown in Figure 9 The excitation signal Tx can be applied through the electrode layer 23 of the ultrasonic sensor 100, and the second pixel electrode 211 can be grounded or in a set state. The piezoelectric layer 22 generates ultrasonic waves under voltage excitation, which propagates along the stacking direction towards the cover plate 200 and the chip 10 respectively, so that each layer (such as the chip substrate 11, the package 12, the redistribution layer 21, the first bonding layer 24 and the protective layer 25) located above and below the piezoelectric layer 22 also resonates. After resonance superposition, at least two ultrasonic wave signals with different frequencies are formed, which pass through the cover plate 200 and reach the detection site (such as a finger) located on the second surface of the cover plate 200.

[0143] Figure 10 An assembly cross-sectional structure diagram of the ultrasonic sensor and the device cover plate in​​Figure 8 Circuit connection diagram of the ultrasonic sensor 100 receiving the echo signal.

[0144] The ultrasonic wave signals of different frequencies reflected by the detected part are transmitted to the piezoelectric layer 22. When the reflected ultrasonic echo signal is received, the second pixel electrode 211 can be used for the collection of the echo signal (the electrical signal converted by the piezoelectric layer 22), and the electrode layer 23 can be grounded or in a set state.

[0145] The piezoelectric layer 22 receives the reflected ultrasonic wave signals of different frequencies and respectively converts the ultrasonic wave signals into electrical signals, which are transmitted to the chip 10 through the second pixel electrode 211 to form at least two biometric information.

[0146] Figure 11 For Figure 3 Another assembly cross-sectional structure diagram of the ultrasonic sensor in the device cover plate.

[0147] Alternatively, in some examples, the ultrasonic sensor 100 can also be fixed with the cover plate 200 in a reverse manner, as shown in Figure 11 The fourth surface (the surface facing away from the piezoelectric layer group 201) of the chip 10 of the ultrasonic sensor 100 can be fixed and adhered to the first surface of the cover plate 200 through the second adhesive layer 300.

[0148] Figure 12 For Figure 11 Loading diagram of the excitation signal of the ultrasonic sensor.

[0149] Correspondingly, as shown in Figure 12 The excitation signal Tx can be applied through the electrode layer 23 of the ultrasonic sensor 100, and the second pixel electrode 211 can be grounded or in a set state.

[0150] Correspondingly, when the reflected ultrasonic wave signal is received, the second pixel electrode 211 collects the electrical signal of the piezoelectric layer 22 and transmits it to the chip 10, and the electrode layer 23 can be grounded or in a set state.

[0151] In the embodiments of the present application, the ultrasonic sensor can emit two frequencies of ultrasonic wave signals, such as low-frequency ultrasonic wave signals and high-frequency ultrasonic wave signals. The low-frequency ultrasonic wave signals can be used for fingerprint detection, and the high-frequency ultrasonic wave signals can be used for heart rate detection as an example.

[0152] Figure 13 For Figure 3 Flowchart of the detection method of the ultrasonic sensor.

[0153] Referring to Figure 13As shown, the ultrasonic sensor emits high frequency ultrasonic signals, and obtains a fingerprint image of the surface of the finger by receiving the reflected high frequency ultrasonic signals. The measurement values in the fingerprint image can be stored in the memory of the ultrasonic sensor, or the obtained fingerprint image can be matched with a stored fingerprint image to achieve detection and identification of the fingerprint. As an example, when the detected fingerprint image matches, a function of the device that is currently disabled can be enabled.

[0154] The ultrasonic sensor emits low frequency ultrasonic signals, and obtains a subcutaneous tissue image by receiving the reflected low frequency ultrasonic signals. The subcutaneous tissue image can be an image formed by one or more depths of tissue inside the surface of the finger. As an example, the ultrasonic sensor can be repeatedly operated to collect subcutaneous tissue images captured over a period of time, and a plurality of image sets can be obtained, each of which can include one or more subcutaneous tissue images. The plurality of image sets can be stored in the memory of the ultrasonic sensor. According to the plurality of image sets, it can be determined whether there is a signal of a rate oscillation within a normal range of subcutaneous tissue (such as the heart, lungs, etc.), and information such as heart rate (or respiratory rate) can be identified and tracked according to the rate oscillation signal.

[0155] It should be noted that the detection of multiple biometric features by the ultrasonic sensor can be simultaneous, or can have a sequence of detection and identification.

[0156] For example, in some examples, the high frequency ultrasonic signals emitted by the ultrasonic sensor can be used as primary frequency signals, and the low frequency ultrasonic signals can be used as secondary frequency signals. The ultrasonic sensor can be mainly used to achieve detection and identification of fingerprints, and detection of heart rate, etc. can be a function that can be achieved after authentication of identity by fingerprint detection and identification. For example, when the detected fingerprint image matches, the identification and tracking of heart rate, etc. can be achieved by the low frequency ultrasonic signals emitted by the ultrasonic sensor.

[0157] Alternatively, in some examples, the high frequency ultrasonic signals and the low frequency ultrasonic signals emitted by the ultrasonic sensor can be used to detect a fingerprint image and detect heart rate, etc. at the same time.

[0158] Of course, in some examples, fingerprint detection and heart rate detection, etc. can also be achieved independently, such as when fingerprint detection is required, detection can be achieved by high frequency ultrasonic signals emitted by the ultrasonic sensor, and when heart rate detection, etc. is required, detection can be achieved by low frequency ultrasonic signals emitted by the ultrasonic sensor.

[0159] In the description of the embodiments of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "mount", "connect", "connection" should be understood broadly, for example, can be fixed connection, can also be indirectly connected through the intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances. The terms "first", "second", "third", "fourth" and the like (if any) are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0160] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the embodiments of the present 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 recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An ultrasonic sensor, characterized by, The chip comprises a chip substrate and a package wrapped around the periphery of the chip substrate, the package being different from the molding material of the chip substrate; The piezoelectric resonant unit comprises a piezoelectric layer group and a protective layer group, which are sequentially stacked on one side of the chip; The piezoelectric layer group is configured to generate ultrasonic waves, and to form at least two different frequency ultrasonic wave signals after the ultrasonic waves pass through the resonance superposition of the chip, the piezoelectric layer group, and the protective layer group, the piezoelectric layer group is also configured to receive the reflected ultrasonic wave signals of different frequencies and convert them into electrical signals respectively to the chip, and the chip is configured to obtain at least two biometric information according to the electrical signals; The at least two different frequency ultrasonic wave signals include a preset frequency ultrasonic wave, each layer in the piezoelectric resonant unit has a corresponding first preset thickness, the chip substrate and the package respectively have a second preset thickness and a third preset thickness, and the first preset thickness, the second preset thickness and the third preset thickness are set according to the frequency value of the preset frequency ultrasonic wave. The second preset thickness and the third preset thickness are equal, the chip substrate and the package form a chip base with consistent thickness, and the thickness of the chip base is negatively correlated with the frequency value of the preset frequency ultrasonic wave.

2. The ultrasonic sensor of claim 1, wherein, The piezoelectric resonant unit satisfies a condition formula: 0.1≤∑(h i / λ i )≤0.4, wherein h i is the first preset thickness of each layer in the piezoelectric resonant unit, and λ i is the wavelength of the preset frequency ultrasonic wave in each layer of the piezoelectric resonant unit.

3. The ultrasonic sensor of claim 2, wherein, The piezoelectric resonant unit satisfies a condition formula:∑(h i / λ i )=1 / 4.

4. Ultrasonic sensor according to claim 2 or 3, characterized in that The ultrasonic sensor satisfies the condition: 0.3≤∑(h i / λ i )+(h a / λ a )≤0.7, where h a is the second preset thickness or the third preset thickness, λ a The preset frequency ultrasonic wave corresponds to a wavelength in the chip substrate or the package.

5. The ultrasonic sensor of claim 4, wherein, The ultrasonic sensor satisfies the conditional formula: ∑(h i / λ i )+(h a / λ a )=1 / 2.

6. The ultrasonic sensor according to any one of claims 1 to 5, characterized in that The third preset thickness is negatively correlated with the frequency value of the preset frequency ultrasonic wave.

7. The ultrasonic sensor according to any one of claims 1 to 5, characterized in that The protective layer group comprises a first adhesive layer and a protective layer, and the protective layer is arranged on the piezoelectric layer group through the first adhesive layer.

8. The ultrasonic sensor according to any one of claims 1 to 7, characterized in that The chip further comprises a plurality of first pixel electrodes, and a plurality of the first pixel electrodes are arrayed on one side of the chip substrate; 9. The ultrasonic sensor according to any one of claims 1 to 8, characterized in that The piezoelectric layer group comprises a redistribution layer, a piezoelectric layer and an electrode layer which are sequentially stacked, the electrode layer is used to apply a voltage excitation to the piezoelectric layer, the piezoelectric layer is used to emit ultrasonic waves under the voltage excitation, and the piezoelectric layer is also used to receive reflected ultrasonic wave signals and convert them into electrical signals; The redistribution layer covers a plurality of the first pixel electrodes, and a plurality of arrayed second pixel electrodes are arranged on the side of the redistribution layer away from the chip, a plurality of the second pixel electrodes are correspondingly connected to a plurality of the first pixel electrodes, and the piezoelectric layer covers a plurality of the second pixel electrodes. The preset frequency ultrasonic wave includes one of high frequency ultrasonic wave or low frequency ultrasonic wave, and the frequency value of the high frequency ultrasonic wave is higher than that of the low frequency ultrasonic wave; 10. The ultrasonic sensor of claim 6, wherein, The thickness of the chip base is 200μm-50μm, and the frequency value of the high frequency ultrasonic wave is 8Mhz-20Mhz or 15Mhz-25Mhz. The preset frequency ultrasonic wave includes one of high frequency ultrasonic wave or low frequency ultrasonic wave, and the frequency value of the high frequency ultrasonic wave is higher than that of the low frequency ultrasonic wave; 11. The ultrasonic sensor of claim 7, wherein, The thickness of the package is 50μm-150μm, and the frequency value of the low frequency ultrasonic wave is 8Mhz-2Mhz. ​ 12. The ultrasonic sensor according to any one of claims 1 to 11, characterized in that The at least two biological characteristic signals include at least one of a fingerprint signal, a heart rate signal, a blood oxygen signal, a blood pressure signal, and a respiration rate signal.

13. A sensor module, characterized by The ultrasonic sensor of any one of claims 1-12 is electrically connected to the control chip.

14. An electronic device, comprising: The ultrasonic sensor of any one of claims 1-12 is fixed to one side of the cover plate. The chip of the ultrasonic sensor is located at an end of the ultrasonic sensor away from the cover plate, or the chip of the ultrasonic sensor is connected to the cover plate.

15. The electronic device of claim 14, wherein, The ultrasonic sensor is further fixed to the cover plate by a second adhesive layer.

16. A vehicle characterized by comprising: The ultrasonic sensor of any one of claims 1-12 is fixed to one side of the cover plate. The chip of the ultrasonic sensor is located at an end of the ultrasonic sensor away from the cover plate, or the chip of the ultrasonic sensor is connected to the cover plate.

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