CN-121971070-A - Flexible piezoelectric type vital capacity tester and preparation method thereof

CN121971070ACN 121971070 ACN121971070 ACN 121971070ACN-121971070-A

Abstract

The invention relates to a flexible piezoelectric type vital capacity tester and a preparation method thereof, wherein the tester comprises a blowing nozzle, a hose and a metal shell which are sequentially arranged from left to right, a gas storage bag, a piezoelectric sensing element, a data processing element and a display screen are arranged in the metal shell, the piezoelectric sensing element comprises a flexible material layer, an electrode and a wire which are made of a piezoelectric electret super-structural material serving as a core sensing material, the flexible material layer, the electrode and the wire are attached to the outer wall of the gas storage bag, the deformation of the gas storage bag is converted into an electric signal in the expansion process, the piezoelectric sensing element has excellent negative poisson ratio auxetic characteristic, isotropic stretching deformation can be synchronously generated along with the expansion of the gas storage bag, the air storage bag is tightly attached to the outer wall of the gas storage bag without gaps, the data processing element is electrically connected with the piezoelectric sensing element for conditioning, sampling and calculating the electric signal and obtaining vital capacity parameters according to the air capacity parameters, and the display screen is electrically connected with the data processing element and used for displaying test results.

Inventors

ZHANG XIAOQING
CHEN YUTONG
SHI ZHIMING
ZHOU LIAN
HU QIANQIAN

Assignees

同济大学

Dates

Publication Date: 20260505
Application Date: 20260326

Claims (10)

1. The flexible piezoelectric type vital capacity tester comprises a blowing nozzle (1), a hose (2) and a metal shell (9), wherein an air storage bag (3), a data processing element (7) and a display screen (8) are arranged in the metal shell (9), and the blowing nozzle (1) is communicated with the air storage bag (3) through the hose (2); The tester is characterized by further comprising a piezoelectric sensing element (10), wherein the piezoelectric sensing element (10) comprises a flexible material layer (5), an electrode (4) arranged on the surface of the flexible material layer and a wire (6) connected with the electrode, the flexible material layer (5) has a negative Poisson ratio characteristic, the flexible material layer (5) synchronously expands in all directions when being stretched, the piezoelectric sensing element (10) is arranged on the outer surface of the air storage bag (3) and synchronously deforms along with deformation of the air storage bag (3), the piezoelectric sensing element (10) is electrically connected with a data processing element (7) through the wire (6), and the data processing element (7) is electrically connected with a display screen (8).
2. A flexible piezoelectric spirometer as claimed in claim 1, characterized in that said flexible material layer (5) comprises a plurality of periodically arranged structural units, each structural unit having a geometry such that the material exhibits a negative poisson's ratio.
3. The flexible piezoelectric spirometer of claim 2, wherein said structural unit includes an upper electret and a lower electret, said upper electret and lower electret having equivalent surface charges of opposite polarity, respectively, and wherein the medium between said upper electret and lower electret is air.
4. A flexible piezoelectric spirometer as claimed in claim 2, characterized in that the substrate of the flexible material layer (5) is a space-charge electret material.
5. The flexible piezoelectric type vital capacity tester according to claim 4, wherein the structural unit has a double-V-shaped structure, and comprises an inner V-shaped inclined edge and an outer V-shaped inclined edge which are nested, wherein the inner V-shaped inclined edge is positioned between the outer V-shaped inclined edge and the air storage bag (3), and an included angle between the outer V-shaped inclined edge and a horizontal plane is larger than an included angle between the inner V-shaped inclined edge and the horizontal plane.
6. A flexible piezoelectric type vital capacity tester as claimed in claim 2, characterized in that the flexible material layer (5) comprises an array combination structure of a plurality of the structural units, both side edges of the array combination structure are provided with blank areas, and the wires (6) are arranged in the blank areas and connected with the structural units.
7. A method for preparing a flexible piezoelectric type vital capacity tester, which is used for the flexible piezoelectric type vital capacity tester according to any one of claims 1 to 6, and is characterized in that the preparation method comprises the following steps: s1, connecting a blowing nozzle (1), a hose (2) and an air storage bag (3) into a whole; S2, manufacturing a flexible material layer (5); S3, manufacturing a piezoelectric sensing element (10); s4, attaching the piezoelectric sensing element (10) to the outer surface of the air storage bag (3) and connecting the piezoelectric sensing element to the data processing element (7); s5, connecting the data processing element (7) to the display screen (8); And S6, finally, the air storage bag (3), the piezoelectric sensing element (10), the data processing element (7) and the display screen (8) are installed in the metal shell (9).
8. The method for manufacturing a flexible piezoelectric type vital capacity tester according to claim 7, wherein the manufacturing process of the flexible material layer (5) comprises the following steps: S201, preparing a template with a double-V structure shape, arranging a plurality of array layouts corresponding to double-V structure units on the template, wherein the included angle between the bevel edge of the outermost layer of each double-V structure unit and the horizontal plane is larger than that between the bevel edge of the innermost layer of each double-V structure unit and the horizontal plane; s202, selecting two dielectric films, and respectively carrying out polarization treatment on the two dielectric films to form a charged layer on the surfaces of the dielectric films; And S203, sequentially attaching the two polarized piezoelectric electret films to the template prepared in the step S201, so that the two dielectric films are adhered to form a preset double V-shaped structure.
9. The method for preparing the flexible piezoelectric type vital capacity tester according to claim 8, wherein the polarization treatment of the dielectric films adopts a corona charging mode, and positive polarization and negative polarization are respectively carried out on the two dielectric films.
10. The method of manufacturing a flexible piezoelectric spirometer according to claim 7, wherein the manufacturing process of the piezoelectric sensor element (10) comprises the steps of: S301, respectively plating electrodes (4) on the outermost layer and the innermost layer of the flexible material layer (5) with the double-V-shaped structure formed by bonding, cutting the flexible material layer (5) after bonding the electrodes into an array combination of a plurality of structural units, and reserving widths on two sides of the array combination; s302, two leads (6) are led out from the left width positions of the two surfaces of the flexible material layer (5) with the double V-shaped structure.

Description

Flexible piezoelectric type vital capacity tester and preparation method thereof Technical Field The invention relates to the technical field of flexible sensing, in particular to a flexible piezoelectric type vital capacity tester and a preparation method thereof. Background The vital capacity is an important physiological index for measuring the respiratory function of a human body, and has wide application in the fields of medical diagnosis, physical monitoring, exercise training and the like. Accurate measurement of lung capacity is of great importance for early screening of respiratory diseases, rehabilitation assessment and athlete physical ability monitoring. The prior vital capacity tester is mainly divided into a float type and an electronic sensor type. The float type tester indirectly calculates the vital capacity by measuring the displacement of the float in water, the mode is complex in operation, the water level needs to be regularly calibrated, the electronic acquisition and the real-time transmission of data cannot be realized, and the clinical application and the remote monitoring are inconvenient. The electronic sensor type tester adopts a pressure sensor or a flow sensor for measurement. The pressure sensor type tester calculates the volume of gas by detecting the pressure change in the gas storage cavity, but the sensor is usually of a rigid structure, requires an external power supply and has poor fitting property with the gas storage cavity during installation. When micro wrinkles or uneven curved surfaces exist on the surface of the gas storage cavity, the rigid sensor is difficult to completely attach to the surface of the cavity, so that the problem of poor local contact and easy detection signal distortion occur, and the measurement accuracy is affected. Flow sensor type testers calculate the vital capacity by measuring the gas flow rate, but flow sensors are sensitive to the direction and speed distribution of the gas flow and are prone to errors when the gas flow is unstable or the exhalation mode is not standard. In addition, the elastic deformation range of the traditional electronic sensor is limited, and the traditional electronic sensor is difficult to adapt to the large deformation of the air storage cavity in the inflation process. When the air storage cavity is inflated, obvious volume expansion and surface stretching can occur, and the rigid or low-elasticity sensor cannot deform synchronously therewith, so that gaps or relative sliding are generated between the sensor and the surface of the cavity, faults such as sensor falling, bonding failure, sensitivity reduction and the like easily occur after long-term use, and the service life and detection stability of the equipment are affected. Therefore, a technical scheme for testing the vital capacity, which can adapt to the deformation of the surface of the air storage cavity, realize close fitting and improve the measurement precision and stability, is needed. Disclosure of Invention The invention aims to overcome the defect of poor measurement precision caused by poor fitting performance of a pressure sensor on an air storage bag in the prior art, and provides a flexible piezoelectric type vital capacity tester and a preparation method thereof. The aim of the invention can be achieved by the following technical scheme: The scheme provides a flexible piezoelectric type vital capacity tester, which comprises a blowing nozzle, a hose and a metal shell, wherein an air storage bag, a data processing element and a display screen are arranged in the metal shell; the tester also comprises a piezoelectric sensing device, wherein the piezoelectric sensing element comprises a flexible material layer, an electrode arranged on the surface of the flexible material layer and a wire connected with the electrode, the flexible material layer has a negative poisson ratio characteristic, the flexible material layer synchronously expands along each direction when being stretched, the piezoelectric sensing element is arranged on the outer surface of the air storage bag and synchronously deforms along with the deformation of the air storage bag, and the piezoelectric sensing element is electrically connected with the data processing element through the wire, and the data processing element is electrically connected with the display screen. Further, the flexible material layer includes a plurality of periodically arranged structural units, and each structural unit has a geometry that causes the material to exhibit a negative poisson's ratio. Further, the structural unit comprises an upper electret and a lower electret, the upper electret and the lower electret respectively have equivalent surface charges with opposite polarities, and a medium between the upper electret and the lower electret is air. Further, the substrate of the flexible material layer is a space charge electret material. Further, the structural unit is of a double-V-shaped str