An automatic phase calibration flexible ultrasonic sensor array

Abstract

The present invention proposes an automatic phase-calibrated flexible ultrasonic sensor array, comprising a sensor housing, a compressive elastomer disposed within the sensor housing, a sensor encapsulation adhesive layer disposed on top of the compressive elastomer, a flexible piezoelectric ultrasonic sensor array and a flexible capacitive sensor array encapsulated within the sensor encapsulation adhesive layer, the flexible piezoelectric ultrasonic sensor array disposed on top of the sensor encapsulation adhesive layer, the flexible capacitive sensor array disposed on the bottom of the sensor encapsulation adhesive layer, the flexible capacitive sensor array connected to the compressive elastomer, and a gap directly disposed between the flexible piezoelectric ultrasonic sensor array and the flexible capacitive sensor array. The present application achieves signal phase distortion calibration during flexible sensor imaging, improving the ultrasonic imaging resolution of complex-shaped structures. Through automatic phase calibration, the present application can improve the imaging quality and positioning accuracy of the flexible ultrasonic sensor array, making it more suitable for a variety of application scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of medical ultrasonic sensors, and in particular to an automatic phase calibration type flexible ultrasonic sensor array. Background Art

[0002] Vascular wall lesions are the basis for the occurrence and development of cardiovascular and cerebrovascular diseases. Changes in arterial stiffness occur earlier than structural changes. Only by conducting early detection on people at high risk of cardiovascular and cerebrovascular diseases and discovering changes in arterial stiffness, and conducting key monitoring and intervention, can we effectively prevent and delay the occurrence and deterioration of cardiovascular and cerebrovascular diseases.

[0003] Medical ultrasound detection of arteriosclerosis is currently one of the most important clinical examination methods, especially for patients with high-risk factors such as hypertension, high cholesterol, and diabetes. Medical ultrasound sensors are an important component of medical ultrasound imaging systems and are directly used for signal sensing. Rigid ultrasound probes are structurally limited and difficult to adapt to the imaging needs of soft or irregular surfaces. However, patch-type flexible ultrasound sensor arrays are conformable and can fit the surface of the part to be inspected, avoiding pressure on soft tissue and minimizing the impact of contact pressure on the morphology of the part to be inspected, greatly broadening the application scenarios of ultrasound transducers.

[0004] Anatomically, the carotid artery is close to vital organs such as the heart and brain, and its arterial pressure is closely related to cardiovascular and cerebrovascular risks. Compared with other blood pressure monitoring methods, arterial blood pressure monitoring based on flexible ultrasonic transducer arrays is less sensitive to motion and can continuously detect blood pressure non-invasively and without occlusion. A flexible ultrasonic sensor array is a sensor system with multiple sensing units that can be arranged in an array on a flexible substrate. This sensor system is often used in fields such as medical diagnosis, structural health monitoring, and non-destructive testing. In these applications, the accuracy and performance of the sensor are often critical.

[0005] Compared to rigid ultrasound probes, flexible ultrasound sensor arrays currently have relatively low sensitivity and resolution. This means their detection capabilities are limited, making it difficult to detect subtle structures or changes. Phase calibration is a key step in ensuring the accurate operation of ultrasound sensor arrays. In ultrasound imaging and signal processing, phase information is crucial for accurately locating targets and reconstructing images. However, due to the manufacturing and environmental conditions of flexible sensor arrays, which can lead to slight differences between sensor units, these differences can cause phase misalignment or mismatch, thus affecting imaging quality and positioning accuracy. Summary of the Invention

[0006] In response to the technical problem in the existing technology that the phase distortion of flexible ultrasonic sensor arrays cannot be fully calibrated, the present invention proposes an automatic phase-calibrated flexible ultrasonic sensor array to achieve signal phase distortion calibration during the flexible sensor imaging process and improve the ultrasonic imaging resolution of complex-shaped structures.

[0007] In order to achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: an automatic phase calibration flexible ultrasonic sensor array, characterized in that it includes a sensor housing, a compressive elastomer is arranged in the sensor housing, a sensor packaging adhesive layer is arranged on the top of the compressive elastomer, a flexible piezoelectric ultrasonic sensor array and a flexible capacitive sensor array are encapsulated in the sensor packaging adhesive layer, the flexible piezoelectric ultrasonic sensor array is arranged on the top of the sensor packaging adhesive layer, the flexible capacitive sensor array is arranged at the bottom of the sensor packaging adhesive layer, the flexible capacitive sensor array is connected to the compressive elastomer, and the flexible piezoelectric ultrasonic sensor array and the flexible capacitive sensor array are directly provided with a gap.

[0008] The flexible piezoelectric ultrasonic sensor array includes an acoustic matching layer, a top electrode, a piezoelectric layer and a bottom electrode which are sequentially arranged from top to bottom.

[0009] The piezoelectric layer is a 1-3 type piezoelectric ceramic, the 1-3 type piezoelectric material uses PZT-5H as a polarizing material and epoxy resin as a filling medium; the top electrode and the bottom electrode are copper foil coated with polyimide.

[0010] The flexible capacitive sensor array includes an upper plate, a capacitor layer, and a lower plate arranged sequentially from top to bottom.

[0011] The capacitor layer is a flexible capacitor layer, which includes at least one capacitor sensor, and the centers of the capacitor sensors are arranged on the same straight line.

[0012] A copper electrode I is also provided on the top of the piezoelectric layer. The copper electrode I is connected to the piezoelectric layer and is connected to the multi-channel ultrasonic imaging system through a shielded signal harness.

[0013] Copper electrodes II are also provided on the upper side of the upper electrode plate and the lower side of the lower electrode plate, and both the upper electrode plate and the lower electrode plate are connected to the copper electrodes II.

[0014] A method for using an automatic phase calibration flexible ultrasonic sensor array comprises the following steps:

[0015] S1: Apply ultrasonic coupling agent evenly to the human neck artery, place the sensor array on the surface of the human neck artery, and gently press the sensor array to ensure a good fit between the sensor array and the neck. Each capacitive sensor obtains pressure data and a contour curve is fitted in real time to measure the contact area contour.

[0016] S2: The fitting curve of the contact part profile measurement is divided into 64 segments, which correspond to the coordinates and tilt angles of the corresponding ultrasonic sensors and are used for phase calibration of the ultrasonic sensors.

[0017] S3: B-ultrasound imaging based on a flexible transducer array is achieved through transmission scanning and echo signal processing technology. The transmission mode is fixed-point focusing sequential scanning. The echo signal undergoes dynamic focusing, variable aperture, amplitude apodization, demodulation, and logarithmic compression processing to generate a carotid artery B-ultrasound image.

[0018] S4: Continuously acquire B-ultrasound images at the same position of the carotid artery, taking a complete contraction-relaxation process of the carotid artery as one cycle, and store 5 consecutive cycles of medical ultrasound images;

[0019] S5: In the medical ultrasound video, track and mark the upper and lower walls of the carotid artery, extract the dynamic information of the carotid artery in each systolic-diastolic cycle, and solve the elastic modulus E of the vascular structure. p1 、E p2 、……、E p5 , take the average value to get the elastic modulus of the vascular structure E p .

[0020] The phase calibration method in step S2 is:

[0021] Extract the z coordinate of the center of each line segment and the line segment deflection angle θ to form (z1,θ1), (z2,θ2), ..., (z 64 ,θ 64 )64 pairs of coordinates are obtained and used as the coordinates of each element of the flexible ultrasonic sensor and input into the B-ultrasound imaging algorithm to eliminate the phase change of the ultrasonic signal caused by the slight change of the position of the flexible ultrasonic sensor element and complete the phase calibration.

[0022] The steps include: the method for obtaining the elastic modulus of the vascular structure in step S4 is:

[0023] When the heart contracts, the highest pressure produced when blood is ejected into the arteries is called systolic pressure. s , at this time the blood vessel cross-sectional radius R s When the heart relaxes, the blood pressure in the arteries drops to the lowest value, which is called diastolic pressure. d , at this time the blood vessel cross-sectional radius R d In the analysis of vascular mechanics, the vascular geometry is considered as a thin-walled elastic tube with a circular cross section, and the vascular structural elastic modulus E is p Characterize the degree of arteriosclerosis:

[0024]

[0025] Among them, R o is the outer diameter of the blood vessel, ΔRo =R d -R s , Δp is the increment of intravascular pressure, Δp=p s -p d .

[0026] The beneficial effects of the present invention are as follows: This application is dedicated to the automatic phase calibration technology of flexible ultrasonic sensors. This technology uses a flexible capacitive sensor array to obtain contact pressure data between the sensor and a complex curved surface. The contact pressure is converted into deformation data by compressing an elastic structure, which is then used to reconstruct the complex curved surface. The surface reconstruction data is then used to obtain the coordinates and line segment deflection angles of all array elements in the flexible piezoelectric ultrasonic sensor array, eliminating phase misalignment in the sensor array. Through automatic phase calibration, the imaging quality and positioning accuracy of the flexible ultrasonic sensor array can be improved, making it more suitable for a variety of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a structural diagram of the flexible ultrasonic sensor of the present invention.

[0029] Figure 2 This is a cross-sectional view of the flexible ultrasonic sensor.

[0030] Figure 3 Create a flow chart for a flexible ultrasonic sensor.

[0031] Figure 4 This is the working flow diagram of the flexible ultrasonic sensor.

[0032] In the figure, 1 is a flexible piezoelectric ultrasonic sensor array, 2 is a flexible capacitive sensor array, 3 is a sensor packaging adhesive layer, 4 is a compression elastomer, 5 is a sensor housing, 6 is copper electrode I, and 7 are copper electrodes II. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0034] like Figure 1As shown, an automatic phase-calibrated flexible ultrasonic sensor array includes a sensor housing 5, a compressive elastic body 4 disposed within the sensor housing, a sensor encapsulation adhesive layer 3 disposed on top of the compressive elastic body 4, and a flexible piezoelectric ultrasonic sensor array 1 and a flexible capacitive sensor array 2 encapsulated within the sensor encapsulation adhesive layer 3. The flexible piezoelectric ultrasonic sensor array 1 is disposed on top of the sensor encapsulation adhesive layer 3, and the flexible capacitive sensor array 2 is disposed on the bottom of the sensor encapsulation adhesive layer 3. The flexible capacitive sensor array 2 is connected to the compressive elastic body 4, and a gap is directly provided between the flexible piezoelectric ultrasonic sensor array 1 and the flexible capacitive sensor array 2. A copper electrode 6 is disposed on top of the flexible piezoelectric ultrasonic sensor array 1 and is connected to the copper electrode 6. The copper electrode 6 is connected to a multi-channel ultrasonic imaging system via a shielded signal harness.

[0035] The flexible piezoelectric ultrasonic sensor array 1 is primarily used for exciting and receiving ultrasonic signals. The flexible capacitive sensor array 2 is primarily used for contact pressure sensing. Combined with the compressive elastomer 4, it can measure compression displacement and reconstruct complex curved surface contours. The sensor encapsulation adhesive layer 3 is primarily used for sensor packaging. The sensor housing 5 is primarily used for sensor structural packaging and support. Copper electrodes 6 are primarily used to connect the ultrasonic sensor array to an external multi-channel ultrasonic imaging system.

[0036] The flexible piezoelectric ultrasonic sensor array 1 includes an acoustic matching layer, a top electrode, a piezoelectric layer, and a bottom electrode, which are arranged in sequence from top to bottom. The piezoelectric layer is connected to the copper electrode I6. Among them, the acoustic matching layer is mainly used for acoustic impedance matching to improve the energy transmission efficiency of the piezoelectric ultrasonic sensor array. The top electrode is mainly used to lead the negative electrode of the piezoelectric ultrasonic sensor to the ultrasonic imaging system. The piezoelectric layer is mainly used for electrical energy-to-acoustic energy conversion and is the core component for realizing ultrasonic transmission and reception. The bottom electrode is mainly used to lead the positive electrode of the piezoelectric ultrasonic sensor to the ultrasonic imaging system.

[0037] The piezoelectric layer utilizes type 1-3 piezoelectric ceramic as the sensing element, with PZT-5H as the polarizing material and epoxy resin as the filling medium. This material better matches the acoustic impedance of human tissue, improving the efficiency of ultrasonic energy transmission. The ultrasonic sensor has a center frequency of 7.5MHz, generating sound waves with a wavelength of λ = 2mm. The longitudinal resolution of B-ultrasound imaging is 1mm, which is high enough for subsequent image interpretation.

[0038] The top and bottom electrodes are made of copper foil coated with polyimide (PI). PI is mainly used to strengthen the copper foil structure. The thickness of the top and bottom electrodes is 20μm, and the thickness of the copper foil is 20μm. The piezoelectric layer, top electrode, and bottom electrode are bonded together with conductive silver glue. The acoustic impedance of the piezoelectric layer of the ultrasonic sensor (Z p ) and the acoustic impedance of human tissue (Z α) is achieved through the acoustic matching layer. According to the KLM transmission line theory, the acoustic matching layer impedance where Z p =8.93Mrayl, Z α =1.5 Mrayl, so Z l =2.72 Mrayl. Epoxy resin E51 material is preferred as the acoustic matching layer, and its sound velocity is measured to be 2540 m / s and its density is 1100 kg / m 3 , the acoustic impedance is 2.78 Mrayl.

[0039] The flexible capacitive sensor array 2 consists of an upper plate, a dielectric layer, and a lower plate, arranged in order from top to bottom. The upper plate is primarily used to connect to the negative terminal of the capacitive acquisition system and accumulate negative charge. The dielectric layer is primarily used to prevent current flow between the two plates and adjust the linearity of the capacitive sensor. The lower plate is connected to the positive terminal of the capacitive acquisition system and accumulates positive charge. The capacitive layer is flexible and contains eight square capacitive sensors forming the capacitive sensor array. The eight square capacitive sensors are arranged in a straight line, each measuring 4 mm wide, 4 mm long, and 1 mm thick, with a center-to-center distance of 6 mm, for a total array length of 46 mm. Copper electrode II 7, comprising 16 copper electrodes, is primarily used to independently connect the upper and lower plates of the eight capacitive sensors to the capacitive acquisition system. A 20 mm thick compressive elastomer 4 made from cured Ecoflex 00-50 is located beneath the square capacitive sensors.

[0040] Example 2

[0041] An automatic phase calibration flexible ultrasonic sensor array, the manufacturing method is as follows:

[0042] When making a flexible piezoelectric ultrasonic sensor array 1, first, the copper electrode and the edges of the upper and lower surfaces of the piezoelectric ceramic are glued together with conductive silver glue, with the bonding length not exceeding 2 mm, to form a structure consisting of a top electrode, a piezoelectric material, and a bottom electrode. The matching layer material epoxy resin E51 is coated on the surface of the piezoelectric ceramic negative electrode of the structure, and allowed to stand for 24 hours to solidify, forming a multilayer structure consisting of a matching layer material-piezoelectric material-electrode. The multilayer structure is glued and fixed on the workbench of a dicing machine using a polyolefin film (150 μm) coated with acrylic pressure-sensitive adhesive (20 μm), and the matching layer on the surface of the piezoelectric ceramic is polished using a dicing machine, retaining the matching layer thickness d = λ m / 4, where λ mThe wavelength of the acoustic wave in the matching layer, d = 85 μm, forms a multilayer structure consisting of the matching layer, piezoelectric material, and electrodes. This multilayer structure is then cut using a dicing saw with a blade thickness of 0.1 mm and a step displacement of 0.7 mm for 65 steps. Excess material is removed, forming a one-dimensional linear array with 64 elements. The elements are 0.6 mm wide, 10 mm long, and 0.8 mm thick, with an element center-to-center distance of 0.7 mm. The total array length is 44.7 mm. The overall structure exhibits excellent flexibility and is bendable.

[0043] The dielectric layer material in the square capacitive sensor is made of a suspension of carbon nanotubes and PDMS material in a mass ratio of 1:50. The mixture is stirred continuously for 24 hours by a stirrer to achieve uniform mixing of the two components.

[0044] In the flexible capacitive sensor array 2, the capacitive sensor is fixed on the compressive elastomer 4 prepared by curing Ecoflex 00-50, and the top of the flexible capacitive sensor array 2 cured and connected to the compressive elastomer 4 and the bottom of the flexible piezoelectric ultrasonic sensor array 1 are bonded by UV glue to form a firm integrated automatic phase calibration ultrasonic sensor.

[0045] A force-capacitance-displacement combined test platform was built using a dynamometer, LCR, and an electric slide. The dynamometer was fixed on the electric slide. Controlling the movement of the electric slide controlled the movement of the dynamometer. A uniaxial compression test was performed on the sensor using the front-end needle of the dynamometer. During the compression process, the displacement Δl, capacitance value C, and dynamometer value F were stored. The stored data was used to establish a force-capacitance relationship curve. The average value of multiple measurements was taken to complete the force-capacitance relationship calibration of 8 capacitive sensors.

[0046] According to the force-capacitance relationship calibration curve, the capacitance value C is inverted to the force F. Combined with the contact area A of the dynamometer and the sensor, the contact pressure P can be obtained.

[0047]

[0048] Under the conditions of known elastic modulus E and thickness l, the elastic body deformation variable Δl can be obtained.

[0049] P=Eε

[0050]

[0051] The deformation variables Δl1~Δl8 of 8 channels are used to fit and reconstruct the complex surface shape.

[0052] The continuous complex surface curve is divided into 64 segments, and the z coordinate of the center of each segment and the segment deflection angle θ are extracted to form (z1, θ1), (z2, θ2), ..., (z 64 ,θ 64)64 pairs of coordinates.

[0053] These coordinates are used as the coordinates of each element of the flexible ultrasonic sensor and input into the B-ultrasound imaging algorithm to eliminate the phase changes of the ultrasonic signal caused by slight changes in the position of the flexible ultrasonic sensor elements, ensure that the signals of all channels are aligned in phase, and realize automatic phase correction of the flexible ultrasonic sensor array.

[0054] The sensor array is placed on the surface of the human carotid artery to obtain medical images of the human neck and store the images for vascular mechanics analysis.

[0055] Arterial blood vessels are elastic and expandable, which can buffer the fluctuation of arterial blood pressure. When the heart contracts, the highest pressure generated when blood is ejected into the artery is called systolic pressure. s , at this time the blood vessel cross-sectional radius R s When the heart relaxes, the blood pressure in the arteries drops to the lowest value, which is called diastolic pressure. d , at this time the blood vessel cross-sectional radius R d In the analysis of vascular mechanics, the vascular geometry is considered as a thin-walled elastic tube with a circular cross section, and the vascular structural elastic modulus E is p Characterize the degree of arteriosclerosis:

[0056]

[0057] Among them, R o is the outer diameter of the blood vessel, ΔR o =R d -R s , Δp is the increment of intravascular pressure, Δp=p s -p d Solve for E p All required variables can be obtained through medical imaging of the human neck, ultimately achieving the characterization of the degree of arteriosclerosis.

[0058] Medical images of the human carotid artery obtained using a flexible ultrasonic sensor with automatic phase calibration function can reduce the compression of blood vessels by contact pressure and obtain accurate medical images of the human carotid artery for accurate analysis of the degree of arteriosclerosis in the human body.

[0059] Example 3

[0060] An automatic phase calibration flexible ultrasonic sensor array, the use method is as follows:

[0061] Step 1: Apply ultrasonic coupling agent evenly to the human neck artery, place the sensor array on the surface of the human neck artery, and gently press the sensor array to ensure a good fit between the sensor array and the neck. The 8-channel capacitive sensor obtains pressure data and fits the contour curve in real time to achieve contact point contour measurement.

[0062] Step 2: The fitting curve of the contact part profile measurement is divided into 64 segments, which correspond to the coordinates and tilt angles of the corresponding ultrasonic sensors. 64 ,θ 64 ) The corresponding ultrasonic sensor array elements are input into the B-ultrasound imaging algorithm for phase calibration of the ultrasonic sensor.

[0063] Step 3: B-ultrasound imaging based on a flexible transducer array is achieved through transmission scanning and echo signal processing. The transmission method is fixed-point focused sequential scanning, and the echo signal undergoes dynamic focusing, variable aperture, amplitude apodization, demodulation, and logarithmic compression to generate a B-ultrasound image of the carotid artery.

[0064] Step 4: Continuously acquire B-ultrasound images at the same position of the carotid artery, taking one complete contraction-relaxation process of the carotid artery as one cycle, and store 5 consecutive cycles of medical ultrasound images for the analysis of the degree of carotid artery sclerosis in step 5.

[0065] Step 5: In the medical ultrasound video, track and mark the upper and lower walls of the carotid artery, extract the dynamic information of the carotid artery in each systolic-diastolic cycle, and solve the elastic modulus E of the vascular structure. p1 、E p2 、……、E p5 , take the average value to get the elastic modulus of the vascular structure E p .

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An automatic phase calibration flexible ultrasonic sensor array, characterized in that: The sensor housing (5) comprises a compressive elastic body (4) provided in the sensor housing (5), a sensor packaging adhesive layer (3) provided on the top of the compressive elastic body (4), a flexible piezoelectric ultrasonic sensor array (1) and a flexible capacitive sensor array (2) encapsulated in the sensor packaging adhesive layer (3), the flexible piezoelectric ultrasonic sensor array (1) being provided on the top of the sensor packaging adhesive layer (3), the flexible capacitive sensor array (2) being provided on the bottom of the sensor packaging adhesive layer (3), the flexible capacitive sensor array (2) being connected to the compressive elastic body (4), and a gap being provided between the flexible piezoelectric ultrasonic sensor array (1) and the flexible capacitive sensor array (2); The flexible piezoelectric ultrasonic sensor array (1) comprises an acoustic matching layer, a top electrode, a piezoelectric layer and a bottom electrode arranged in sequence from top to bottom; The flexible capacitive sensor array (2) comprises an upper plate, a capacitive layer and a lower plate arranged in sequence from top to bottom; The capacitor layer is a flexible capacitor layer, and the flexible capacitor layer includes 8 square capacitor sensors, and the centers of the 8 square capacitor sensors are arranged on the same straight line; A copper electrode I (6) is also provided on the top of the piezoelectric layer, the copper electrode I (6) is connected to the piezoelectric layer, and the copper electrode I (6) is connected to the multi-channel ultrasonic imaging system through a shielded signal harness; Copper electrodes II (7) are also provided on the upper side of the upper electrode plate and the lower side of the lower electrode plate, respectively, and both the upper electrode plate and the lower electrode plate are connected to the copper electrodes II (7); The flexible piezoelectric ultrasonic sensor array (1) is used for exciting and receiving ultrasonic signals, and the flexible capacitive sensor array (2) is used for contact pressure sensing. The flexible piezoelectric ultrasonic sensor array can measure the compression displacement in combination with the compressive elastic body (4) and fit the contact part contour curve in real time. The coordinates and line segment deflection angles of all array elements of the flexible piezoelectric ultrasonic sensor array are obtained by using the real-time fitting of the contact part contour curve, thereby eliminating the phase misalignment in the flexible piezoelectric ultrasonic sensor array and realizing automatic phase calibration of the flexible piezoelectric ultrasonic sensor array.

2. The automatic phase calibration flexible ultrasonic sensor array according to claim 1, characterized in that: The piezoelectric layer is a 1-3 type piezoelectric ceramic, which uses PZT-5H as a polarizing material and epoxy resin as a filling medium; the top electrode and the bottom electrode are copper foil coated with polyimide.

3. The method for using the automatic phase calibration flexible ultrasonic sensor array according to claim 1 or 2, characterized in that: The steps include: S1: Apply ultrasonic coupling agent evenly to the human neck artery, place the automatic phase calibration flexible ultrasonic sensor array on the surface of the human neck artery, and gently press the automatic phase calibration flexible ultrasonic sensor array to ensure good contact between the automatic phase calibration flexible ultrasonic sensor array and the neck artery. Each square capacitive sensor obtains contact pressure and fits the contact part contour curve in real time. S2: Divide the contour curve of the contact part into 64 line segments, obtain the coordinates of all array elements and line segment deflection angles of the flexible piezoelectric ultrasonic sensor array, eliminate the phase misalignment in the flexible piezoelectric ultrasonic sensor array, and realize automatic phase calibration of the flexible piezoelectric ultrasonic sensor array; Step S2 includes: extracting the z Coordinates and line segment deflection angles ,form A total of 64 pairs of coordinates are used as the coordinates of each element of the flexible piezoelectric ultrasonic sensor array and input into the B-ultrasound imaging algorithm to eliminate the phase changes of the ultrasonic signal caused by slight changes in the position of the flexible piezoelectric ultrasonic sensor array elements, thereby realizing automatic phase calibration of the flexible piezoelectric ultrasonic sensor array. S3: Ultrasound imaging based on a flexible piezoelectric ultrasonic sensor array is achieved through transmission scanning and echo signal processing technology. The transmission mode is fixed-point focusing sequential scanning. The echo signal undergoes dynamic focusing, variable aperture, amplitude tracking, demodulation and logarithmic compression processing to generate a B-ultrasound image of the carotid artery. S4: Continuously acquire B-ultrasound images at the same position of the carotid artery, taking a complete contraction-relaxation process of the carotid artery as one cycle, and storing the medical ultrasound image formed by 5 consecutive cycles of B-ultrasound images; S5: In medical ultrasound images, track and mark the upper and lower walls of the carotid artery, extract the dynamic information of the carotid artery in each systolic-diastolic cycle, and solve for the elastic modulus of the vascular structure. E p1 、 E p2 、……、 E p5 , taking the average value to obtain the elastic modulus of the vascular structure E p .

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