Blood pressure monitoring device with piezoelectric needle PMUTs

Abstract

The application discloses a blood pressure monitoring device of piezoelectric needle type PMUT. The blood pressure monitoring device comprises a piezoelectric sensor module, a CMOS circuit module and a wearable assembly. The piezoelectric sensor module comprises a substrate, a sensor array layer and a packaging layer which are sequentially stacked, and a PMUT device at least partially protruding from a surface of the packaging layer. The PMUT device comprises a piezoelectric layer and an electrode layer which are sequentially stacked. The piezoelectric layer covers a top surface of the substrate, and the piezoelectric layer covers a bottom surface of the packaging layer. The CMOS circuit module is integrated with the piezoelectric sensor module. The wearable assembly is used for mounting the piezoelectric sensor module and the CMOS circuit module and provides a wearing function. The piezoelectric sensor module detects a pulse and converts mechanical energy into electrical energy. Output charges pass through a data processing module. According to a piezoelectric dynamics principle of an arterial pulse, an output voltage waveform is converted into a blood pressure value output by a micro-processing unit, and a real-time blood pressure monitoring function is completed. The device is simple to operate, accurate in measurement and can be mass-produced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blood pressure measurement, and particularly relates to a blood pressure monitoring device of piezoelectric needle type PMUT. BACKGROUND

[0002] Hypertension is a major cardiovascular disease factor affecting more than 1 billion people worldwide. Because of the characteristics of the related symptoms not easy to be perceived, long-term monitoring of blood pressure is very important. Clinically, blood pressure measurement still mainly adopts a sphygmomanometer based on a cuff. This is not convenient for daily carrying and long-term use, especially for hypertensive patients who need to monitor blood pressure index for a long time. If the hypertensive patients do not receive timely treatment, they are prone to suffer from serious diseases such as coronary heart disease and stroke.

[0003] With the rapid popularization of wearable devices, intelligent wearable devices with personal health monitoring functions developed for the field of intelligent health have attracted widespread attention of people. According to different measurement principles, these wearable devices are classified into a bracelet photoplethysmography (PPG) method, a bracelet photoplethysmography plus electrocardiography (PPG+ECG) method, and a bracelet oscillograph method. However, the reliability of the blood pressure values measured by the existing intelligent bracelet is still questionable.

[0004] The photoplethysmography method is that the bracelet emits a photoelectric signal to the skin, and the pulse wave of the wrist part is collected by a sensor to estimate the blood pressure value. However, the photoelectric sensor is very sensitive to the surrounding light, and the stability and reproducibility are poor. On the basis of the photoelectric signal, several metal sheets are added to collect the electrocardiogram signal, and the blood pressure value is estimated by comprehensively combining the two signals. However, the fingers of the hand on the side where the bracelet is not worn need to press the metal button on the surface when the bracelet is used. The measurement principle of the electronic sphygmomanometer is the oscillograph method. Generally, the back of the bracelet has a micro air bag, and a pressure sensor is used for detection and control. Through the processes of inflation, pressurization, and deflation, the blood pressure is calculated by a small pulse, which leads to a large measurement data error and a relatively complex operation. SUMMARY

[0005] Therefore, the present application provides a blood pressure monitoring device of piezoelectric needle type PMUT, which is accurate in measurement and simple in operation.

[0006] The present application provides a blood pressure monitoring device of piezoelectric needle type PMUT, which comprises:

[0007] A piezoelectric sensor module comprises a substrate, a sensor array layer, and a packaging layer which are sequentially stacked, the sensor array is formed by arrangement of at least one PMUT device, the PMUT device at least partially protrudes from the surface of the packaging layer, the PMUT device comprises a piezoelectric layer and an electrode layer which are sequentially stacked, the piezoelectric layer is covered on the top surface of the substrate, and the piezoelectric layer is covered on the bottom surface of the packaging layer;

[0008] a CMOS circuit module integrated with the piezoelectric sensor module, used to process and convert the pulse pressure information collected by the piezoelectric sensor module into blood pressure information;

[0009] and a wearable assembly for mounting the piezoelectric sensor module and the CMOS circuit module and used to provide a wearable function.

[0010] Optionally, the piezoelectric sensor module is a single-chip structure or a double-chip structure as a whole.

[0011] Optionally, the piezoelectric layer is made of any one or more of aluminum nitride, scandium-doped aluminum nitride, PZT, PVDF, LiNbO3, LiTaO3, and PMN-PT.

[0012] Optionally, the encapsulation layer is made of TPU or PDMS.

[0013] Optionally, the substrate layer is made of any one or more of silicon, PDMS, and polytetrafluoroethylene (PTFE).

[0014] Optionally, the PMUT device is made by a back cavity etching process or a process of an SOI substrate with a cavity filled with a matching layer or a coupling agent.

[0015] Optionally, the matching layer or the coupling agent is made of PDMS.

[0016] Optionally, the CMOS circuit module includes an analog circuit and a digital circuit, and the digital circuit includes a processing circuit, a microprocessor unit, and a wireless communication unit.

[0017] Optionally, the wearable assembly is provided with a display screen, a key, an alarm, or a voice broadcaster.

[0018] The piezoelectric needle type PMUT blood pressure monitoring device provided above can detect a pulse and convert mechanical energy into electrical energy by the PMUT device of the piezoelectric sensor module, output the electrical charge through the conversion of the CMOS circuit module amplification circuit into a blood pressure value, and thus complete the real-time blood pressure monitoring function. This method is simple to operate, can reduce the cost of the blood pressure monitoring device, and reduce the measurement error. When in use, the wearable assembly only needs to be fixed to a human body part to be tested. Since the PMUT device at least partially protrudes from the surface of the encapsulation layer, the PMUT device can be better attached to the skin surface, and the operation is relatively simple. In addition, since the PMUT device is used, the volume is reduced, and mass production is difficult to achieve. BRIEF DESCRIPTION OF DRAWINGS

[0019] The technical solutions and other beneficial effects of the present application will be apparent from the following detailed description of specific embodiments of the present application, combined with the accompanying drawings.

[0020] Figure 1 is a schematic diagram of a use state of a blood pressure monitoring device of the present application;

[0021] Figure 2 is another schematic diagram of a use state of a blood pressure monitoring device of the present application;

[0022] Figure 3 is a structural schematic diagram of a wearable assembly of the present application;

[0023] Figure 4 is a structural simple cross-sectional schematic diagram of a blood pressure monitoring device of an embodiment of the present application.

[0024] Figure 5 is a structural simple cross-sectional schematic diagram of a manufacturing process of a piezoelectric needle type packaged PMUT pulse blood pressure monitoring system proposed by the present application, which is different from Figure 4 a manufacturing process of a piezoelectric needle type packaged PMUT pulse blood pressure monitoring system proposed by the present application.

[0025] Figure 8 is a preparation process cross-sectional schematic diagram of a piezoelectric needle type packaged PMUT proposed by the present application.

[0026] Figure 9 is a structural simple top view schematic diagram of a piezoelectric needle type packaged PMUT pulse blood pressure monitoring system proposed by the present application.

[0027] Figure 10 is a component block diagram of a monitoring method of the present application.

[0028] In the figure, the elements are identified as follows:

[0029] 101, 202, 400, 500, 600, 700, 900 - blood pressure monitoring device; 201 - artery; 301 - wristband type wearable assembly; 302 - neck type wearable assembly; 303 - adhesive plaster type wearable assembly; 401, 501, 601, 701, 903, 809 - packaging layer; 402, 502, 602, 702 - electrode layer; 403, 503, 603, 703 - piezoelectric layer; 404, 504, 604, 704, 801 - substrate; 405, 505, 605, 705, 901, 810 - adhesive layer; 406, 506, 606, 706, 811 - CMOS circuit module; 407, 507, 607, 707 - sensor array layer; 408, 508, 608, 708, 902 - PMUT device; 709 - coupling agent; 802 - substrate needle type structure; 803 - bottom electrode layer; 804 - first piezoelectric layer; 805 - middle electrode layer; 806 - second piezoelectric layer; 807 - top electrode layer; 808 - cavity substrate. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0031] In the description of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified and limited.

[0032] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements or the interaction between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] The following disclosure provides many different embodiments or examples for implementing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific examples of processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0034] Reference Figure 1, pulse refers to the pulsation of the artery 201. The pressure change caused by the heart pulsation makes the aorta 201 wall vibrate and transmit to the periphery along the artery 201 wall, that is, the pulse. The human body artery 201 is directly connected to the heart and distributed throughout the body, and the commonly referred to pulse is usually felt on the radial side of the wrist, which can reflect the functional status of the blood circulation system. The examination method of pulse palpation can usually determine the lesion site and the corresponding symptoms. The blood pressure monitoring device 101, 202, 400, 500, 600, 700, 900 of the present application is located at the wrist or neck.

[0035] Please refer to Figure 2 , the working principle of the blood pressure monitoring system is the piezoelectric dynamics of the artery 201 pulse, which is one of the extended components of the hemodynamics about the piezoelectric electromechanical coupling characteristics of the artery 201 pulse, and is the basis for further monitoring blood pressure by piezoelectric sensor. It is found through research that the artery 201 pulse wave is directly related to the blood pressure wave, so the blood pressure wave can be obtained by converting the directly monitored artery 201 pulse wave.

[0036] Reference Figures 4-7 , Figure 9 , Figure 10 , the piezoelectric needle type PMUT blood pressure monitoring device 101, 202, 400, 500, 600, 700, 900 of the present application comprises:

[0037] a piezoelectric sensor module, which comprises a substrate 404, 504, 604, 704, 801, a sensor array layer 407, 507, 607, 707 and a packaging layer 401, 501, 601, 701, 903, 809 stacked in turn, the above-mentioned sensor array is formed by arranging at least one PMUT device 408, 508, 608, 708, 902, the above-mentioned PMUT device 408, 508, 608, 708, 902 at least partially protrudes from the surface of the above-mentioned packaging layer 401, 501, 601, 701, 903, 809, the above-mentioned PMUT device 408, 508, 608, 708, 902 comprises a piezoelectric layer 403, 503, 603, 703 and an electrode layer 402, 502, 602, 702 stacked in turn, the above-mentioned piezoelectric layer 403, 503, 603, 703 covers the top surface of the above-mentioned substrate 404, 504, 604, 704, 801, and the above-mentioned piezoelectric layer 403, 503, 603, 703 covers the bottom surface of the above-mentioned packaging layer 401, 501, 601, 701, 903, 809;

[0038] A CMOS circuit module 406, 506, 606, 706, 811 is integrated with the piezoelectric sensor module to process and convert the pulse pressure information collected by the piezoelectric sensor module into blood pressure information.

[0039] A wearable assembly is provided for mounting the piezoelectric sensor module and the CMOS circuit module 406, 506, 606, 706, 811 and to provide a wearable function.

[0040] It should be understood that, as a demonstrative implementation of the PMUT device 408, 508, 608, 708, 902 "at least partially protruding from the surface of the encapsulation layer 401, 501, 601, 701, 903, 809", the PMUT device 408, 508, 608, 708, 902 can be in the form of a protruding needle. The encapsulation layer 401, 501, 601, 701, 903, 809 does not completely cover the top surface of the PMUT device, i.e. the encapsulation layer 401, 501, 601, 701, 903, 809 covers part of the top surface of the PMUT device 408, 508, 608, 708, 902. As a more common implementation to achieve better contact with the skin to be measured, the encapsulation layer 401, 501, 601, 701, 903, 809 covers the surrounding area of the PMUT device 408, 508, 608, 708, 902 to expose the top surface of the PMUT device 408, 508, 608, 708, 902.

[0041] The encapsulation layer 401, 501, 601, 701, 903, 809 can be tightly attached to the skin by a suitable adhesive layer 405, 505, 605, 705, 90, etc. A pre-stress is generated in the film before measurement, thereby increasing the sensing pressure during measurement, increasing the receiving sensitivity of the PMUT, and making the measurement result more accurate and reliable.

[0042] As to the number of PMUT devices 408, 508, 608, 708, 902, there can be multiple PMUT devices 408, 508, 608, 708, 902 according to actual needs. The arrangement of the PMUT devices 408, 508, 608, 708, 902 can be in a dot matrix arrangement or in a random arrangement.

[0043] In a typical embodiment, the piezoelectric sensor module is in a single wafer structure or a dual wafer structure.

[0044] In a typical embodiment, the piezoelectric layer 403, 503, 603, 703 is made of any one or more of aluminum nitride, scandium-doped aluminum nitride, PZT, PVDF, LiNbO3, LiTaO3, and PMN-PT.

[0045] In one typical embodiment, the material of the encapsulation layer 401, 501, 601, 701, 903, 809 is TPU or PDMS.

[0046] In one typical embodiment, the material of the substrate 404, 504, 604, 704, 801 layer is any one or more of silicon, PDMS, polytetrafluoroethylene PTFE.

[0047] In one typical embodiment, the PMUT device 408, 508, 608, 708, 902 is made by a back cavity etching or a cavity SOI substrate 404, 504, 604, 704, 801 process, and the cavity is filled with a matching layer or couplant 709.

[0048] Here, the material of the matching layer or couplant 709 is PDMS.

[0049] The PMUT device 408, 508, 608, 708, 902 can be obtained by using a semiconductor process well known to those skilled in the art, for example, MEMS refers to a micro device or system that can be mass produced, and integrates micro mechanisms, micro sensors, micro actuators, and signal processing and control circuits, communication interfaces, and power supplies, etc. on one or more chips, and has the advantages of miniaturization, integration, low cost, high performance, and mass production.

[0050] As an implementation manner of the wearable assembly, please refer to Figure 3 The present application is not limited to this, and can be a bracelet assembly 301, a neck assembly 302, and a wearable assembly 303 in the form of a band-aid. The material can be fixed by a comfortable elastic fabric or a flexible material. In addition, the measurement site is not limited to this, and can be the radial artery 201 of the wrist, or other arteries 201 with strong pulse such as the carotid artery 201.

[0051] The wearable assembly is provided with a display screen, an alarm, or a voice broadcaster. In this way, the measured blood pressure information can be presented on the external devices such as the display, the alarm, and the voice broadcaster. The blood pressure information can be operated by pressing the keys.

[0052] As a demonstrable implementation of the CMOS circuit module 406, 506, 606, 706, 811, the CMOS circuit module 406, 506, 606, 706, 811 includes analog circuit and digital circuit modules, and the data processing module can accurately and continuously record the arterial pulse wave 201, including processing circuit, microprocessor unit and wireless communication module. The working principle of data processing is that the sensor array layer 407, 507, 607, 707407 detects the pulse and converts the mechanical energy into electrical energy, and the output charge is processed by the charge conversion, filtering and amplification of the CMOS circuit layer 406 processing circuit, and the output voltage waveform is converted into blood pressure value by the microprocessor unit, that is, the real-time blood pressure detection function is completed. In other embodiments, the blood pressure monitoring device 101, 202, 400, 500, 600, 700, 900 is embedded in a wearable appearance, and the external device such as a display device can be used by the user to view information and perform corresponding operations, such as viewing time, body temperature, local temperature, humidity, etc., and the measured blood pressure value and other information; the monitoring alarm function, such as when the blood pressure value is abnormal, the display is always on and the alarm is sounded. However, the type or function of the external device of the blood pressure monitoring device 101, 202, 400, 500, 600, 700, 900 of the present application is not limited to this.

[0053] In the CMOS circuit module 406, 506, 606, 706, 811, the microprocessor unit included in the data processing module can be implemented by any suitable microprocessor such as FPGA (Field Programmable Gate Array). In addition, in other embodiments, the data can be transmitted to a smart terminal such as a smart phone through a wireless communication module to generate a blood pressure report and provide the wearer with more detailed diagnosis and treatment reports and suggestions. Figure 9 The assembly block diagram in this embodiment is shown in FIG. 8.

[0054] Please refer to Figure 8 , Figure 8 0 in the above table is the unprocessed state, and 1-10 are steps S1-S10. As a demonstrable implementation, the preparation process of the piezoelectric sensor module of the present application is as follows:

[0055] S1: Etch the front surface of the substrate 404, 504, 604, 704, 801 to form a raised substrate needle structure 802.

[0056] S2: Deposit a bottom electrode layer 803 on the substrate needle structure 802.

[0057] S3: Deposit a first piezoelectric layer 804 on the bottom electrode layer 803.

[0058] S4: Deposit a middle electrode layer 805 on the first piezoelectric layer 804.

[0059] S5: depositing a second piezoelectric layer 806 on the middle electrode 805.

[0060] S6: depositing a top electrode layer 807 on the second piezoelectric layer 806.

[0061] S7: etching the substrate 404, 504, 604, 704, 801 to form a cavity substrate 808.

[0062] S8: forming a flexible encapsulation layer 401, 501, 601, 701, 903, 809.

[0063] S9: pasting a flexible pasting layer 405, 505, 605, 705, 901, 810 on the substrate 404, 504, 604, 704, 801.

[0064] S10: integrating a CMOS circuit layer 406, 506, 606, 706, 811 on the back of the cavity substrate 808.

[0065] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A piezoelectric needle-type PMUT blood pressure monitoring device, characterized in that, include: A piezoelectric sensor module includes a substrate, a sensor array layer, and an encapsulation layer stacked sequentially. The top surface of the substrate has a raised pin-like structure. The sensor array layer is formed by arranging at least one PMUT device. The PMUT device is a raised pin-like structure at the raised pin-like structure. The PMUT device at least partially protrudes from the surface of the encapsulation layer. The PMUT device includes a piezoelectric layer and an electrode layer stacked sequentially. The piezoelectric layer covers the top surface of the substrate and the bottom surface of the encapsulation layer. The encapsulation layer is used to adhere tightly to the skin via an adhesive layer. A CMOS circuit module is integrated with the piezoelectric sensor module to process and convert the pulse pressure information collected by the piezoelectric sensor module into blood pressure information. In addition, a wearable assembly for mounting the piezoelectric sensor module and the CMOS circuit module to provide wearable functionality.

2. The blood pressure monitoring device according to claim 1, characterized in that, The piezoelectric sensor module is a single-chip or dual-chip structure.

3. The blood pressure monitoring device according to claim 1, characterized in that, The material of the piezoelectric layer is any one or more of aluminum nitride, scandium-doped aluminum nitride, PZT, PVDF, LiNbO3, LiTaO3, and PMN-PT.

4. The blood pressure monitoring device according to claim 1, characterized in that, The encapsulation layer is made of TPU or PDMS.

5. The blood pressure monitoring device according to claim 1, characterized in that, The substrate layer is made of one or more of silicon, PDMS, and polytetrafluoroethylene (PTFE).

6. The blood pressure monitoring device according to claim 1, characterized in that, The PMUT device is fabricated using a process of back cavity etching or a cavity-filled SOI substrate, wherein the cavity is filled with a matching layer or a coupling agent.

7. The blood pressure monitoring device according to claim 6, characterized in that, The matching layer or coupling agent material is PDMS.

8. The blood pressure monitoring device according to claim 1, characterized in that, The CMOS circuit module includes analog circuits and digital circuits, and the digital circuits include processing circuits, microprocessor units, and wireless communication units.

9. The blood pressure monitoring device according to claim 1, characterized in that, The wearable assembly is equipped with a display screen, buttons, an alarm, or a voice broadcaster.

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