Flexible ultrasonic patch for monitoring corneal elastic modulus and preparation method thereof

Abstract

The invention discloses a flexible ultrasonic patch for monitoring cornea elastic modulus and a preparation method thereof. The patch comprises a top flexible packaging layer, a top electrode layer, a piezoelectric layer, a bottom electrode layer, a bottom flexible base material isolation layer and a bottom flexible packaging layer from top to bottom. And an air column is arranged in the piezoelectric layer. Compared with a traditional medical hard probe for measuring the mechanical property of the cornea, the medical hard probe has good flexibility, the tensile property and the bending resistance are greatly improved, the patch can be dynamically attached to the surface of an eyelid, and long-time cornea health monitoring of the human body is achieved; meanwhile, the application scene of the device is widened through the non-invasive monitoring mode, corneal elasticity modulus real-time monitoring in the night sleep process can be achieved, and other eye characteristics such as intraocular pressure can be further obtained.

Description

Technical Field

[0001] The invention belongs to the field of flexible electronic technology, and in particular relates to a flexible ultrasonic patch for monitoring corneal elastic modulus and a preparation method thereof. Background Art

[0002] Corneal elastic modulus is one of the important parameters for assessing corneal health. Measuring corneal elastic modulus is very important clinically. It can help assess intraocular pressure more accurately, which is crucial for the diagnosis and monitoring of glaucoma. At the same time, it can help identify corneal diseases such as keratoconus at an early stage and take timely treatment measures. Knowing the corneal elastic modulus before refractive surgery can assist doctors in developing personalized surgical plans and improve surgical safety and effectiveness. For researchers, testing the corneal elastic modulus helps to gain a deeper understanding of the biomechanical properties of the cornea and its impact on eye health, providing theoretical support for the development of new diagnostic tools and technologies. For patients who have undergone corneal surgery, regular examination of the corneal elastic modulus is an effective way to evaluate surgical outcomes and monitor potential complications. Therefore, the measurement of corneal elastic modulus plays a key role in many aspects.

[0003] At present, the technologies used to monitor corneal elastic modulus include: ultrasound imaging, corneal topograph, optical coherence tomography, Scheimpflug imaging, corneal biomechanical analysis, etc. Among them, ultrasound imaging is a widely used technology in the field of medical monitoring. It has the characteristics of non-invasive, high resolution, and real-time imaging. It can image corneal tissue in real time and with high precision, monitor corneal elastic modulus, and thus evaluate the health of the cornea.

[0004] At present, most ultrasound devices in the field of medical monitoring use rigid ultrasound probes, which are applied to the patient's eyelids with coupling agents and require the operation of professional medical staff. Manually moving the ultrasound probe will not only cause tactile effects on the patient, but also lead to monitoring errors due to mistakes made by medical staff. For air-blowing elastic imaging methods, the cornea will be directly contacted, causing discomfort to the patient, and real-time measurement is impossible. For patients with glaucoma, keratoconus, etc., monitoring the corneal elastic modulus during sleep at night is particularly important. How to dynamically monitor the corneal elastic modulus non-invasively, in real time, with high precision and almost imperceptibly has become the biggest challenge for ultrasound devices. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a flexible ultrasonic patch for monitoring the corneal elastic modulus, which includes, from top to bottom, a top flexible packaging layer, a top electrode layer, a piezoelectric layer, a bottom electrode layer, a bottom flexible substrate isolation layer and a bottom flexible packaging layer; an air column is provided inside the piezoelectric layer; the piezoelectric layer also has an array assembled from a number of ultrasonic transducer units, and the ultrasonic transducer units are spaced apart by air columns, and the materials of the flexible ultrasonic patch are all composed of polymers and their composites.

[0006] Specifically, the bottom electrode layer and the top electrode layer serve as ports for receiving and transmitting signals, respectively, and both the bottom electrode layer and the top electrode layer are arranged in a pattern.

[0007] Specifically, the material of the bottom flexible encapsulation layer includes silicone elastomer Ecoflex-0030, polyurethane elastomer, PET film, and PDMS elastomer.

[0008] Specifically, the material of the flexible substrate isolation layer includes polyimide and epoxy resin.

[0009] Specifically, the material of the top flexible packaging layer includes polyparaxylene, polyparaxylene C, polyimide, polytetrafluoroethylene, and polybenzoxazole, and the thickness of the top flexible packaging layer is 5-10 microns.

[0010] Specifically, the thickness of the piezoelectric layer is 80-150 microns.

[0011] A method for preparing a flexible ultrasonic patch is also provided, wherein the flexible ultrasonic patch is any of the above-mentioned flexible ultrasonic patches, and specifically comprises the following steps:

[0012] preparing a bottom flexible substrate isolation layer;

[0013] Vapor depositing and patterning a bottom electrode layer on the bottom flexible substrate isolation layer;

[0014] The piezoelectric layer is prepared by a hot embossing method;

[0015] Evaporating and patterning a top electrode layer on top of the piezoelectric layer;

[0016] preparing a top flexible encapsulation layer on top of the top electrode layer;

[0017] Package bottom flexible packaging layer.

[0018] Specifically, the method of preparing the piezoelectric layer by hot embossing method comprises the following steps:

[0019] Creating a master mold with a columnar structure by photolithography, wherein the properties of the columnar structure include shape, pattern and height; casting the master mold with PDMS and curing it to produce a PDMS stamp with a columnar structure cavity;

[0020] A layer of film is pressed onto the bottom electrode layer, the film is heated to soften it, and a PDMS stamp is pressed into the film so that the softened film fills the columnar structure cavity of the PDMS stamp. After the stamping is completed, the PDMS stamp is released; another layer of film is laminated on the top to form an air column and an ultrasonic transducer unit, and finally a piezoelectric layer is made.

[0021] The film is treated with oxygen plasma before being pressed onto the bottom electrode layer.

[0022] Specifically, the material of the main mold is epoxy resin; the material of the film is one of polyvinylidene fluoride and its copolymer, and flexible piezoelectric ceramics.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The flexible ultrasonic patch for monitoring corneal elastic modulus provided by the present invention can be used for monitoring corneal elastic modulus, including but not limited to monitoring corneal elastic modulus. Compared with traditional ultrasonic rigid probes and traditional corneal measurement tools, the present invention is soft and comfortable, does not directly contact the cornea, can fit the eyelid, broadens the use scenarios of corneal elastic modulus monitoring, and fills the gap in the field of nighttime corneal elastic modulus monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the cross-sectional structure of a flexible ultrasonic patch according to an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the top view of the piezoelectric layer of the flexible ultrasonic patch according to an embodiment of the present invention.

[0027] Figure 3 Schematic diagram of the working principle of the flexible ultrasonic patch according to an embodiment of the present invention.

[0028] The markings in the figure are:

[0029] Top flexible packaging layer 1, top electrode layer 2, piezoelectric layer 3, air column 4, bottom electrode layer 5, bottom flexible substrate isolation layer 6, bottom flexible packaging layer 7, ultrasonic transducer unit 8, flexible ultrasonic patch 10, eyelid 11, cornea 12, ultrasonic pulse 13, shear wave 14, displacement 15. DETAILED DESCRIPTION

[0030] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0032] It can be understood that the terms "first", "second", etc. used in the present application can be used in this article to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element.

[0033] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0034] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0035] In order to make the purpose, technical solution and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] The flexible ultrasonic patch for monitoring corneal elastic modulus provided in this embodiment is composed of a multi-layer structure, which includes, from bottom to top: a bottom flexible packaging layer 7 made of elastomer for fitting with the eyelid 11, a bottom flexible substrate isolation layer 6 made of polyimide with a thickness of about 10 microns as a substrate for the electrode, a 200-nanometer gold electrode layer evaporated on the top of the polyimide, a piezoelectric layer 3 made by hot embossing, the structure of the piezoelectric layer 3 includes an array of 64 ultrasonic transducers, the material of the ultrasonic transducer is polyvinylidene fluoride and its copolymer P (VDF-TrFE) with a thickness of 80-150 microns, an electrode layer with a thickness of 200-400 nanometers is deposited on the top of the piezoelectric layer 3, and finally a C-type polyimide with a thickness of about 5-10 microns is used to form a conductive film. The xylene film is packaged to form a top flexible packaging layer 1; in one specific example, each electrode of the flexible ultrasonic patch 10 is connected to an external electronic control system, the input power is changed by the electronic control system, and the time delay and phase difference of the piezoelectric unit in each piezoelectric layer 3 are calculated, and then the emission time and direction of each unit of the central 16 ultrasonic transducers are set, and high-energy ultrasonic pulses with the same focus are emitted, which are precisely focused on a point on the cornea. All 64 ultrasonic transducer units 8 of the piezoelectric layer 3 receive the reflected ultrasonic signal, detect the displacement 15 of the tissue caused by strain, and image these displacements 15, construct a space-time diagram, and calculate the propagation speed of the shear wave by linear fitting and other algorithms, and then calculate the elastic modulus of the corneal tissue;

[0037] Specifically, if Figure 1 and Figure 3 As shown, the internal structure of the flexible ultrasonic patch 10 includes a top flexible packaging layer 1, a top electrode layer 2, a piezoelectric layer 3, a bottom electrode layer 5, a bottom flexible substrate isolation layer 6 and a bottom flexible packaging layer 7; an air column 4 is provided inside the piezoelectric layer 3 (the piezoelectric layer 3 is composed of an ultrasonic transducer unit 8 and an air column 4, and the material of the ultrasonic transducer unit 8 is the piezoelectric layer material); from bottom to top: the bottom flexible packaging layer 7 is placed at the bottom as a functional layer directly bonded to the eyelid 11, the bottom electrode layer 5 is patterned and evaporated on the bottom flexible substrate isolation layer 6 made of polyimide, the piezoelectric layer 3 is formed into an air column 4 by hot stamping, and electrode deposition is continued above the piezoelectric layer 3 to form a top electrode layer 2, and finally the entire device is packaged, and a top flexible packaging layer 1 is made on the top.

[0038] In order to further improve the applicability of monitoring the corneal elastic modulus of this embodiment, the thickness of the piezoelectric layer 3 (i.e., the thickness of the ultrasonic transducer) is adjusted, thereby changing the ultrasonic frequency so that the piezoelectric resonance frequency is within the range of 4-10 MHz, which can adapt to different eyelid 11 thicknesses and corneal depths.

[0039] The bottom flexible packaging layer 7 is used to package the internal structure to avoid external interference, and is soft and comfortable and can fit the eyelid 11.

[0040] The purpose of the bottom flexible substrate isolation layer 6 is to serve as a substrate for the electrode material, so that the electrode can be better evaporated and adhered, and as a substrate, it can be better transferred from the glass.

[0041] The bottom electrode layer 5 and the top electrode layer 2 are intended to serve as ports for receiving and transmitting signals, wherein the bottom electrode layer 5 and the top electrode layer 2 are arranged in a pattern.

[0042] The piezoelectric layer 3 is located between the bottom electrode layer 5 and the top electrode layer 2 electrodes, and its purpose is to transmit and receive ultrasonic waves. It can convert voltage signals into ultrasonic signals, or convert ultrasonic signals into voltage signals and output them; the columnar structure is to reduce signal crosstalk between each other.

[0043] The flexible ultrasonic patch 10 described in this embodiment is composed of polymers and their composites, and has good stretchability and bendability. Specifically:

[0044] The bottom flexible packaging layer 7 is made of materials including but not limited to silicone elastomer Ecoflex-0030, polyurethane elastomer, PET film, PDMS elastomer and the like.

[0045] The bottom flexible substrate isolation layer 6 is made of materials including but not limited to polyimide, epoxy resin and the like.

[0046] The materials of the bottom electrode layer 5 and the top electrode layer 2 include but are not limited to metal materials such as gold, silver, and copper.

[0047] The piezoelectric layer 3 is made of materials including but not limited to flexible piezoelectric materials such as polyvinylidene fluoride and its copolymer P (VDF-TrFE), flexible piezoelectric ceramics, etc.

[0048] The top flexible packaging layer 1 includes, but is not limited to, packaging materials such as Parylene N, Parylene C, polyimide (PI), polytetrafluoroethylene (PTFE), and polybenzoxazole (PBO).

[0049] The flexible ultrasonic patch for monitoring the corneal elastic modulus provided in this embodiment has a thickness of only 200-400 microns and a weight of only 1-5 grams. It is soft and light and can fit well with the eyelid 11.

[0050] This embodiment also provides a method for preparing the above-mentioned flexible ultrasonic patch, comprising the following steps:

[0051] (a) First, a layer of polyimide film with a thickness of about 10 μm is spin-coated and cured on a temporary glass slide to prepare a bottom flexible substrate isolation layer 6;

[0052] (b) a 200 nm thick composite material is deposited on the polyimide film by sputtering as a bottom electrode, and then a patterned bottom electrode layer 5 is prepared by photolithography;

[0053] (c) Preparation of the stamp: The stamp mold is formed by patterning epoxy resin on a separate glass substrate using photolithography technology to form a master mold with a columnar structure, including shape (such as square, hexagon and circle), pattern and height. After that, PDMS (polydimethylsiloxane) is used to cast the master mold and solidify it (PDMS is a liquid substance composed of a body and a cross-linking agent, which is heated to 80 degrees for 60 minutes to solidify. The melting point of the solidified PDMS stamp is 200-300°C) to produce an embossed stamp, i.e. a PDMS stamp with a columnar structure cavity; the PDMS stamp is a soft mold, which is more suitable for large-area embossing than a hard mold, because the mold can be released more gently from the edge and gradually cover the entire panel.

[0054] (d) A layer of P(VDF-TrFE) film about 50 μm thick is laminated onto the prepared bottom electrode layer 5. In order to improve the adhesion strength, the P(VDF-TrFE) film is treated with oxygen plasma directly before lamination to improve the adhesion. The P(VDF-TrFE) film layer is heated to 160°C (slightly higher than the melting point of P(VDF-TrFE)) to soften the P(VDF-TrFE) film layer, and the PDMS stamp is pressed into the P(VDF-TrFE) film layer so that the material of the P(VDF-TrFE) film layer fills the cavity in the PDMS stamp. After the imprinting is completed, the PDMS stamp is released slowly and evenly; when the PDMS stamp is removed, a columnar structure of about 70 microns in height and a P (VDF-TrFE) film layer of about 10 microns thick under the columnar structure are formed. After releasing the PDMS stamp, a layer of P (VDF-TrFE) film about 20 microns thick is laminated on the top of the columnar structure again to finally form a piezoelectric layer 3 and an air column 4. After being heated and softened, the top 20-micron P (VDF-TrFE) film will partially flow into the columnar structures on the bottom substrate, thereby providing a flat surface for the subsequent deposition of the top electrode; the piezoelectric layer 3 formed here is composed of arrayed ultrasonic transducer units 8 and air columns 4 separating each ultrasonic transducer unit 8.

[0055] (e) A common top electrode layer 2 with a pattern is deposited by physical vapor deposition technology, and C-type polyparaxylene is used as the top flexible encapsulation layer 1 to protect the internal structure from the influence of the external environment.

[0056] like Figure 2 The piezoelectric layer 3 includes a plurality of air columns 4 arranged in an array and having a hexagonal cross section, which mechanically isolate adjacent ultrasonic transducer units 8. This greatly reduces the acoustic crosstalk between adjacent acoustic elements, and the structure of the air columns 4 and the absence of piezoelectric ceramics increase the mechanical flexibility of the entire array, enhance the bendability, and provide the possibility of fitting to curved surfaces. At the same time, the hexagonal column shape and reasonable air spacing increase the piezoelectric effective area.

[0057] like Figure 2 In some embodiments, the piezoelectric layer 3 is arranged in a columnar array structure, with a total of 64 ultrasonic transducer units 8, preferably polyvinylidene fluoride and its copolymer P (VDF-TrFE). The acoustic impedance of this material is similar to that of human tissue, and the matching performance is better, so there is no need for a coupling layer, and there is no need to apply a coupling agent on the surface of the patient's eyelid 11 for acoustic coupling. In some embodiments, the piezoelectric layer 3 material is composed of polyvinylidene fluoride and its copolymer P (VDF-TrFE) with a thickness of 80-150 microns. In a specific example, the piezoelectric layer 3 material is polyvinylidene fluoride and its copolymer P (VDF-TrFE) with a thickness of 80 microns; in some embodiments, the thickness of the top electrode layer 2 is 200-400 nanometers, and in a specific example, the thickness of the top electrode layer 2 is 400 nanometers. In some embodiments, the top flexible encapsulation layer 1 is a C-type polyparaxylene film with a thickness of 5-10 microns. In a specific example, the top flexible encapsulation layer 1 is a C-type polyparaxylene film with a thickness of 5 microns.

[0058] The bottom flexible packaging layer 7 is made of a flexible material, and in some embodiments, the silicone elastomer Ecoflex-0030 is preferably used to fit the surface of the eyelid 11 when worn by the patient, and to package the internal structure to isolate interference from the external environment. The thickness is about 200 microns.

[0059] like Figure 3 In this embodiment, when measuring the corneal elastic modulus, the flexible ultrasonic patch 10 is tightly fitted to the eyelid 11, and a focused ultrasonic pulse 13 is emitted from the flexible ultrasonic patch 10 to a point on the cornea 12. After the point on the cornea undergoes elastic deformation, a shear wave 14 is generated. Then, the flexible ultrasonic patch is switched to a receiving mode to receive the reflected ultrasonic wave and detect the displacement 15 of the focal tissue. By constructing a time-space diagram of the displacement 15, the shear wave velocity is obtained through algorithms such as linear fitting, and then the elastic modulus of the corneal tissue is calculated.

[0060] The principle of the present invention for monitoring the elastic modulus of the cornea is as follows: a flexible ultrasonic patch is placed on the eyelid 11 of a lying patient so that the patch fits tightly against the closed eyelid 11 of the patient, a signal generator and a power amplifier are connected to the electrodes of the flexible ultrasonic patch, the emission time and phase of the 16 ultrasonic transducer units 8 in the center of the piezoelectric layer 3 are calculated by a program algorithm, so that the signal generator generates different voltage signals at both ends of the electrode, and then the ultrasonic power is amplified by the power amplifier, thereby prompting the piezoelectric layer 3 to emit a higher-power ultrasonic pulse signal to the same point on the corneal tissue, causing the cornea to produce a slight elastic deformation, and then all the ultrasonic transducer units 8 receive the ultrasonic wave reflected by the corneal tissue, construct a displacement 15 image of the tissue, and obtain the propagation velocity of the shear wave by linear fitting and other algorithms, and calculate the elastic modulus of the cornea by the formula for calculating the elastic modulus.

[0061] The formula for calculating the corneal elastic modulus by shear wave elastography in the present invention is:

[0062] ,in is the elastic modulus of the cornea, is the density of the cornea, is the shear wave propagation velocity.

[0063] The flexible ultrasonic patch for monitoring corneal elastic modulus provided by the present invention can be used for monitoring corneal elastic modulus, including but not limited to monitoring corneal elastic modulus. Compared with traditional ultrasonic rigid probes and traditional corneal measurement tools, the present invention is soft and comfortable, does not directly contact the cornea, can fit the eyelid, broadens the use scenarios of corneal elastic modulus monitoring, and fills the gap in the field of nighttime corneal elastic modulus monitoring.

[0064] Compared with the prior art, the present invention has the following significant advantages:

[0065] The flexible ultrasonic patch for monitoring corneal elastic modulus provided by the present invention can be used for monitoring corneal elastic modulus, including but not limited to monitoring corneal elastic modulus. Compared with traditional ultrasonic rigid probes and traditional corneal measurement tools, the present invention is soft and comfortable, does not directly contact the cornea, can fit the eyelid, broadens the use scenarios of corneal elastic modulus monitoring, and fills the gap in the field of nighttime corneal elastic modulus monitoring.

[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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A flexible ultrasonic patch for monitoring corneal elastic modulus, characterized in that: From top to bottom, it includes a top flexible packaging layer (1), a top electrode layer (2), a piezoelectric layer (3), a bottom electrode layer (5), a bottom flexible substrate isolation layer (6) and a bottom flexible packaging layer (7); an air column (4) is provided inside the piezoelectric layer (3); an array composed of a plurality of ultrasonic transducer units (8) is also provided inside the piezoelectric layer (3), and the ultrasonic transducer units (8) are spaced apart by air columns (4), and the material of the flexible ultrasonic patch is composed of polymers and their composites.

2. The flexible ultrasonic patch for monitoring corneal elastic modulus according to claim 1, characterized in that: The bottom electrode layer (5) and the top electrode layer (2) serve as ports for receiving and transmitting signals respectively, and both the bottom electrode layer (5) and the top electrode layer (2) are arranged in a pattern.

3. The flexible ultrasonic patch for monitoring corneal elastic modulus according to claim 1, characterized in that: The materials of the bottom flexible encapsulation layer (7) include silicone elastomer Ecoflex-0030, polyurethane elastomer, PET film, and PDMS elastomer.

4. The flexible ultrasonic patch for monitoring corneal elastic modulus according to claim 1, characterized in that: The material of the flexible substrate isolation layer (6) includes polyimide and epoxy resin.

5. The flexible ultrasonic patch for monitoring corneal elastic modulus according to claim 1, characterized in that: The material of the top flexible packaging layer (1) includes polyparaxylene, polyparaxylene C, polyimide, polytetrafluoroethylene, and polybenzoxazole. The thickness of the top flexible packaging layer (1) is 5-10 microns.

6. The flexible ultrasonic patch for monitoring corneal elastic modulus according to claim 1, characterized in that: The thickness of the piezoelectric layer (3) is 80-150 microns.

7. A method for preparing a flexible ultrasonic patch, characterized in that: The flexible ultrasonic patch is the flexible ultrasonic patch according to any one of claims 1 to 6, and specifically comprises the following steps: preparing a bottom flexible substrate isolation layer (6); Vapor-depositing a bottom electrode layer (5) on a bottom flexible substrate isolation layer (6) and patterning the layer; A piezoelectric layer (3) is prepared by a hot embossing method; Vapor depositing a top electrode layer (2) on top of the piezoelectric layer (3) and patterning it; Preparing a top flexible encapsulation layer (1) on top of the top electrode layer (2); The bottom flexible encapsulation layer (7) is encapsulated.

8. The method for preparing a flexible ultrasonic patch according to claim 7, characterized in that: The method of preparing the piezoelectric layer (3) by using a hot embossing method specifically comprises the following steps: Creating a master mold with a columnar structure by photolithography, wherein the properties of the columnar structure include shape, pattern and height; casting the master mold with PDMS and curing it to produce a PDMS stamp with a columnar structure cavity; A thin film is pressed onto the bottom electrode layer (5), the film is heated to soften it, a PDMS stamp is pressed into the film so that the softened film fills the columnar structure cavity of the PDMS stamp, and the PDMS stamp is released after the stamping is completed; a thin film is laminated again on the top to form an air column (4) and an ultrasonic transducer unit (8), and finally a piezoelectric layer (3) is manufactured.

9. The method for preparing a flexible ultrasonic patch according to claim 8, characterized in that: The film is subjected to an oxygen plasma treatment before being pressed onto the bottom electrode layer (5).

10. The method for preparing a flexible ultrasonic patch according to claim 8, characterized in that: The material of the main mold is epoxy resin; the material of the film is one of polyvinylidene fluoride and its copolymer, and flexible piezoelectric ceramics.

Images