A flexible dielectric acoustic resonator based local facial ultrasound enhanced penetration patch structure

Abstract

The application discloses a local facial ultrasonic penetration promoting patch structure based on flexible dielectric acoustic resonance, which comprises an ultrasonic penetration promoting patch, a coupling layer and a driving circuit module. In one aspect, the application is based on pure dielectric electrostatic driving of a piezoelectric material, and is matched with interdigitated electrodes, so that the overall thickness of the patch can be controlled to be less than 200 microns, and the flexibility of the patch area can be matched. In another aspect, the application is based on sound cavitation penetration promotion, and is matched with the targeted delivery depth (from the epidermis to the superficial dermis) of the cosmetic active substance in the coupling layer, while the impedance matching is used to reduce sound reflection loss, and the excessive heating of deep tissues caused by ultrasound is avoided. In addition, the patch structure can be reused by replacing the coupling layer each time, so that the user economy, skin contact comfort and hygiene safety are considered to the greatest extent.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine, specifically relating to a localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance. Background Technology

[0002] The outermost layer of human skin, the stratum corneum, is a highly keratinized lipid barrier about 10-20 μm thick, which can effectively prevent external substances from entering the skin. For active ingredients with a molecular weight greater than 500 Da, such as hyaluronic acid (>1 million Da), collagen (>300,000 Da), peptides and other large molecular cosmetic active substances, the transdermal absorption rate under traditional application methods is usually only 5%-10%. Most of the active ingredients cannot penetrate the stratum corneum to reach the target skin layer, resulting in severely limited product efficacy. Ultrasonic permeation is a physical permeation method that uses ultrasonic energy to temporarily increase skin permeability. Its basic mechanism includes: (1) sound waves generate periodic pressure fluctuations in the liquid medium, causing temporary disorder of the lipid bilayer structure of the stratum corneum; (2) under specific conditions, acoustic cavitation effect is generated, and the growth and collapse of cavitation bubbles generate microjets, forming transient microchannels in the stratum corneum, which greatly reduces the transdermal transmission resistance of large molecular substances.

[0003] However, traditional ultrasound penetration enhancement devices are mostly handheld rigid probes (made of piezoelectric ceramic materials), which have the following limitations: 1. They require full handheld operation, making it impossible to achieve long-term continuous application for penetration enhancement; 2. Rigid probes cannot closely fit curved areas of the face (such as nasolabial folds and around the eyes), resulting in uneven coupling and low ultrasound energy transmission efficiency; 3. The devices are large and costly, making them unsuitable for home beauty applications. Flexible wearable ultrasound patches, represented by piezoelectric transducer arrays based on polydimethylsiloxane (PDMS) encapsulation and electrostatic resonant transducers based on dielectric thin films, make it possible to integrate the ultrasound generating unit into a flexible substrate. However, existing flexible ultrasound patch solutions still have the following shortcomings when targeting the specific application scenario of localized facial beauty: 1) Existing ultrasonic transdermal penetration-enhancing patches are all based on piezoelectric driving mechanisms (piezoelectric materials such as PZT, ZnO, AlN, and PVDF). The preparation process of piezoelectric ceramic discs or piezoelectric films is complex and costly, and the inherent brittleness of piezoelectric ceramics limits the flexible folding ability of the patches. 2) Existing solutions are all designed for large-area uniform coverage of the entire face, without taking into account the anatomical differences (curvature, skin thickness, sensitivity, treatment area) of local facial areas such as nasolabial folds, eye area, and forehead. This results in uniform ultrasound output parameters having poor effects or safety risks in some areas (such as excessive ultrasound stimulation around the eyes). 3) Existing flexible ultrasonic patches have an integrated design of transducer components and skin contact components (such as transducers embedded in the mask substrate), which requires the entire patch to be discarded after use, resulting in waste of electronic components and high cost per use. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an improved local facial ultrasound permeation-enhancing patch structure based on flexible dielectric acoustic resonance.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A localized facial ultrasound-enhanced penetration patch structure based on flexible dielectric acoustic resonance includes an ultrasound-enhanced penetration patch, a coupling layer, and a driving circuit module. The ultrasound-enhanced penetration patch comprises a front encapsulation layer, an electrode structure layer, and a back encapsulation layer arranged sequentially. The coupling layer is adhered to the back encapsulation layer. Specifically, the thickness of the ultrasound-enhanced penetration patch is less than 200 mm. The electrode structure layer includes a flexible dielectric film layer, interdigitated electrode layers formed on the front side of the flexible dielectric film layer, and a ground electrode layer formed on the back side of the flexible dielectric film layer. The ground electrode layer and the interdigitated electrodes constitute a normal electric field component along the piezoelectric layer normal. The interdigitated electrode layer includes a first comb electrode and a second comb electrode arranged along the width of the facial application area. The first and second comb electrodes are staggered vertically or horizontally based on the contour of the facial application area and are spaced apart. The driving circuit module is located on the interdigitated electrodes. An AC voltage signal is applied between the layer and the ground electrode layer to generate a periodic alternating electrostatic field between the two interlaced comb electrodes. This alternating electrostatic field applies a periodic electrostatic force to the flexible dielectric film layer, driving it to undergo periodic mechanical vibration at a frequency synchronized with the AC signal, ranging from micrometers to nanometers in size. The coupling layer is a biocompatible hydrogel coupling layer. The sound waves generated by the vibration of the flexible dielectric film layer are transmitted to the biocompatible hydrogel coupling layer through the back encapsulation layer, and then to the skin via the hydrogel medium. The liquid components and intercellular fluid in the hydrogel form microbubbles in the negative pressure phase of the sound pressure fluctuation. The bubbles undergo stable volume oscillations during the sound wave cycle or collapse violently under high pressure. The cosmetic active substances loaded in the biocompatible hydrogel coupling layer diffuse into the epidermis and dermis through the microchannels of the stratum corneum under the permeation promotion of the bubbles.

[0006] Preferably, the bubble-enhanced penetration effect includes microjet effect, lipid bilayer perturbation, and acoustic flow effect. The microjet effect refers to the high-speed microjet generated by the asymmetric collapse of bubbles directly impacting the stratum corneum, forming transient microchannels. Lipid bilayer perturbation refers to the periodic pressure perturbation of the lipid bilayer between stratum corneum cells by sound waves, reducing diffusion resistance. The acoustic flow effect refers to the steady-state acoustic flow caused by sound waves in the liquid promoting the convective transport of active substances into the skin. In other words, the oscillation and collapse (inertial cavitation) of bubbles (acoustic cavitation nuclei) generate the following effects to promote the transdermal penetration of active substances. Compared to the 1-5MHz of traditional cosmetic ultrasound and the less than 220kHz of mid-frequency ultrasound, the ultrasound within 20MHz of this method has a greater sound wave attenuation coefficient in tissue, and the energy deposition is more concentrated within 2mm below the epidermis, matching the targeted delivery depth of cosmetic active substances (epidermis to superficial dermis), while avoiding excessive heating of deep tissues that may be caused by low-frequency ultrasound.

[0007] According to a specific embodiment and preferred aspect of the present invention, the first comb electrode includes a first comb back arranged along the wide upper contour of the facial application area and multiple first comb teeth arranged side by side on the first comb back; the second comb electrode includes a second comb back arranged along the wide lower contour of the facial application area and multiple second comb teeth arranged side by side on the second comb back; wherein the first comb back and the second comb back are staggered vertically, and the first comb teeth and the second comb teeth alternate and staggered; and / or, the first comb electrode and the second comb electrode are flexible electrodes, and are respectively deposited or printed on the front side of a flexible dielectric film layer; and / or, the width of the first comb teeth and the second comb teeth is 30-150 μm, and the spacing between the first comb teeth and the second comb teeth is 30-150 μm. In short, the interdigitated electrode layer is deposited on the upper surface of the flexible dielectric film and consists of two sets of comb-shaped interlaced metal electrodes, each set of electrodes containing multiple parallel extending finger conductors, the finger conductors of the two sets of electrodes being alternately interlaced. The preferred electrode material is Cr / Au (5-10 nm chromium adhesion layer + 50-200 nm gold conductive layer), but other highly conductive metal materials (such as Al, Pt, Ag, etc.) can also be used. The electrode is prepared by photolithography-metal deposition-lifting process or screen printing process.

[0008] Preferably, the key geometric parameters of the interdigitated electrodes are: the width (line width) of the comb teeth is 30-150 μm, preferably 70 μm; the spacing between adjacent comb teeth is 30-150 μm, preferably 70 μm; the total number of comb teeth can be set to 10-200 pairs according to the effective sound-generating area requirement. Simultaneously, two sets of interdigitated electrodes are connected to the positive (or inverting) terminal of the AC drive signal, and the other set is connected to the negative (or positive) terminal of the AC drive signal. A high-frequency AC voltage is applied between the two sets of electrodes to generate an alternating electrostatic field.

[0009] According to a specific embodiment and preferred aspect of the present invention, the flexible dielectric film layer is a polyimide film, a polyvinylidene fluoride film, or other flexible polymer films with low dielectric loss and high breakdown field strength; and / or, the thickness of the flexible dielectric film layer is 15-150 μm. That is, the flexible dielectric film layer is located between the interdigitated electrode layer and the lower surface ground electrode layer, serving as the core element for dielectric elastic vibration. The preferred material is a polyimide (PI) film, and alternative materials include polyvinylidene fluoride (PVDF) films or other flexible polymer films with low dielectric loss and high breakdown field strength. The thickness of the PI film is 15-150 μm, preferably 25-100 μm, more preferably 25 μm or 50 μm. The thickness of the PI film directly affects the acoustic resonant frequency and resonant efficiency; a thinner film produces a larger vibration amplitude under the same driving voltage.

[0010] According to another specific embodiment and preferred aspect of the present invention, the ground electrode layer is a solid metal layer deposited on the lower surface of the flexible dielectric film. The ground electrode layer is a solid (unpatterned) metal layer deposited on the lower surface of the flexible dielectric film. The preferred material is Cr / Au (5-10 nm chromium adhesion layer + 50-200 nm gold conductive layer), but other highly conductive metals may also be used. The ground electrode layer is connected to the ground terminal (GND) of the driving circuit, forming a vertical electric field distribution between it and the interdigitated electrodes on the upper surface.

[0011] According to another specific embodiment and preferred aspect of the invention, the biocompatible hydrogel coupling layer is a replaceable disposable component; and / or, the biocompatible hydrogel coupling layer is a polyvinyl alcohol hydrogel, polyacrylamide hydrogel, or chitosan-based hydrogel; and / or, the thickness of the biocompatible hydrogel coupling layer is 0.2-2.0 mm. The hydrogel coupling layer, being a replaceable disposable component, is located between the lower PDMS encapsulation layer and the skin surface, and is detachably connected to the transducer patch body by physical adhesion or mechanical snap-fit. The hydrogel material is preferably polyvinyl alcohol (PVA) hydrogel, polyacrylamide (PAAm) hydrogel, or chitosan-based hydrogel, with a thickness of 0.2-2.0 mm. The core functions of the hydrogel coupling layer are: (i) to serve as an acoustic coupling medium, filling the microscopic gap between the patch and the skin surface, and impedance matching to reduce acoustic reflection loss; (ii) to provide soft cushioning and improve wearing comfort; and (iii) to selectively preload cosmetic active substances (such as hyaluronic acid, collagen, peptides, niacinamide, vitamin C derivatives, etc.) to be delivered to the skin during use with the ultrasound-enhanced permeation.

[0012] According to another specific embodiment and preferred aspect of the invention, the driving circuit module is disposed on one side edge or the non-sound-emitting area of ​​the back of the patch, and the driving circuit module includes a pulse width modulation controller with an adjustable duty cycle, a signal generator, a power amplifier, and a battery; and / or, the driving circuit module outputs an AC driving signal with a frequency of 10-40MHz and a peak-to-peak voltage of 10-200V to the interdigitated electrodes. The driving circuit module applies a high-frequency AC voltage signal (frequency about 10-40MHz, preferably about 20MHz) between the interdigitated electrode layer and the ground electrode layer, generating a periodic alternating electrostatic field between the alternating interdigitated electrode teeth. This alternating electric field applies a periodic electrostatic force (Maxwell stress) to the flexible dielectric film (PI) located between the interdigitated electrode layer and the ground electrode layer, driving the PI film to undergo periodic mechanical vibrations at the micrometer to nanometer scale at a frequency synchronized with the AC signal. The driving circuit module, disposed on one side edge or the non-sound-emitting area of ​​the back of the patch, includes a miniature high-frequency signal generator, a power amplifier, and a button battery (such as CR2032, 3V). The drive circuit outputs an AC drive signal with a frequency of 10-40MHz (preferably about 20MHz) and a peak-to-peak voltage of 10-200V to the interdigitated electrodes. The drive circuit may include a pulse width modulation (PWM) control unit with an adjustable duty cycle to achieve an intermittent operating mode.

[0013] In some specific embodiments, the thickness of the front encapsulation layer is 50-200 μm; the front encapsulation layer provides electrical insulation protection and flexible support for the electrode structure layer, and the material is polydimethylsiloxane. That is, the front encapsulation layer is located on the outermost side of the patch, uses polydimethylsiloxane (PDMS) material, and has a thickness of 50-200 μm. Its main functions are: (i) to provide electrical insulation protection for the lower IDE electrode to prevent short circuits caused by contact with external conductors during use; (ii) to provide flexible structural support, the elastic modulus of PDMS is adjustable, and the patch is flexible; (iii) PDMS has good biocompatibility and meets the requirements of ISO10993 standard.

[0014] In some specific embodiments, the thickness of the back encapsulation layer is 20-100 μm, and it provides insulation protection for the ground electrode to form a mechanical transition interface at the interface of the biocompatible hydrogel coupling layer.

[0015] In addition, the facial application areas include the nasolabial fold area, the area around the eyes, and the forehead area. When applying to the nasolabial fold area, the contour of the facial application area extends along the nasolabial groove, with the comb-shaped electrodes alternating between left and right, resulting in an effective sound-emitting area of ​​1.5–4.0 cm². 2The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–70%, and a single application time of 10–20 min. It is applied to the periorbital area, with the facial application area avoiding direct contact with the eyes. The comb-shaped electrodes are alternately spaced, and the effective sound-generating area is 0.8–2.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.5–2.0 mm, a duty cycle of 30–50%, and a single application time of 5–10 min. It is applied to the forehead area, with the facial application area in a trapezoidal shape. The comb-shaped electrodes are alternately spaced, and the effective sound-generating area is 3.0–8.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–80%, and a single treatment time of 10–20 minutes. In short, the skin in the nasolabial fold area is relatively thick (approximately 2 mm of epidermis + dermis), and the treatment goal is to improve wrinkles and promote deep penetration; it can withstand moderate to high ultrasound intensity. The skin around the eyes is the thinnest (approximately 0.5 mm) and has the highest sensitivity, requiring strict control of ultrasound power and treatment time to ensure safety. The forehead area is relatively flat, with a large area and moderate skin thickness, suitable for even coverage and a longer treatment time.

[0016] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art: Existing transdermal ultrasound penetration-enhancing patches, based on piezoelectric driving mechanisms (piezoelectric materials such as PZT, ZnO, AlN, and PVDF), involve complex and costly fabrication processes for piezoelectric ceramic discs or films. Furthermore, the inherent brittleness of piezoelectric ceramics limits the patch's flexibility and folding capabilities. Additionally, their design, intended for large-area uniform coverage of the entire face, fails to consider the anatomical differences (curvature, skin thickness, sensitivity, and treatment area) of localized facial regions such as nasolabial folds, the eye area, and the forehead. This results in inconsistent ultrasound output parameters in some areas or potential safety risks (e.g., excessive ultrasound stimulation around the eyes). Moreover, the transducer and skin contact components are often integrated (e.g., the transducer is embedded in the mask substrate), requiring complete disposal after use, leading to wasted electronic components and high per-use costs. This invention, based on a flexible dielectric acoustic resonance-based localized facial ultrasound penetration-enhancing patch structure, cleverly solves these shortcomings. Using this ultrasonic penetration-enhancing patch structure, mechanical vibration is first generated by electrostatic drive, causing the dielectric film to resonate acoustically. The process involves two main steps: first, sound waves are coupled to the skin via a hydrogel, and the acoustic cavitation effect opens the microchannels of the stratum corneum; second, the cosmetic active substances (such as hyaluronic acid, peptides, collagen, niacinamide, etc.) loaded in the hydrogel coupling layer diffuse into the epidermis and dermis through the microchannels of the stratum corneum under the action of the acoustic cavitation-promoting mechanism, achieving efficient delivery. After the ultrasound is discontinued, the microchannels of the stratum corneum naturally close under the skin's own repair mechanism, without permanent damage. Therefore, this invention, on the one hand, is based on pure dielectric electrostatic drive without piezoelectric materials, combined with interdigitated electrodes, which not only controls the overall thickness of the patch to within 200μm, but also matches the flexible curvature of the application area; on the other hand, based on acoustic cavitation-promoting penetration, it matches the targeted delivery depth of the cosmetic active substances in the coupling layer (from the epidermis to the superficial dermis), while impedance matching reduces acoustic reflection loss and avoids excessive heating of deep tissues that may be caused by ultrasound. In addition, the patch structure can be reused each time the coupling layer is replaced, maximizing user economy, skin contact comfort, and hygiene safety. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the local facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance of the present invention; Figure 2 for Figure 1 Diagram of the structure and usage status of the ultrasonic permeation-enhancing patch (applied to the nasolabial fold area). Figure 3 for Figure 1 Diagram of the structure and usage of the ultrasound-enhanced permeation patch (applied to the periorbital area). Figure 4 for Figure 1 Diagram of the structure and usage of the ultrasound-enhanced penetration patch (applied to the forehead area). Figure 5 for Figure 1State diagrams are used in this context; The structure includes: 1. Ultrasonic permeation-enhancing patch; 10. Front encapsulation layer; 11. Electrode structure layer; 110. Flexible dielectric film layer; 111. Interdigitated electrode layer; s1. First comb tooth electrode; s10. First comb back; s11. First comb tooth; s2. Second comb tooth electrode; s20. Second comb back; s21. Second comb tooth; 112. Ground electrode layer; 12. Back encapsulation layer; 2. Coupling layer; 3. Drive circuit module; 4. Skin layer. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] like Figure 1 As shown, the local facial ultrasound permeation-enhancing patch structure based on flexible dielectric acoustic resonance in this embodiment includes an ultrasound permeation-enhancing patch 1, a coupling layer 2, and a driving circuit module 3.

[0025] Specifically, the ultrasonic permeation-enhancing patch 1 includes a front encapsulation layer 10, an electrode structure layer 11, and a back encapsulation layer 12 arranged sequentially, with a coupling layer 2 adhered to the back encapsulation layer 12, and the thickness of the ultrasonic permeation-enhancing patch 1 is less than 200 mm.

[0026] In some specific embodiments, the thickness of the front encapsulation layer 10 is 50-200 μm; the front encapsulation layer 10 provides electrical insulation protection and flexible support for the electrode structure layer 11, and the material is polydimethylsiloxane. That is, the front encapsulation layer 10 is located on the outermost side of the patch, uses polydimethylsiloxane (PDMS) material, and has a thickness of 50-200 μm. Its main functions are: (i) to provide electrical insulation protection for the lower IDE electrode to prevent short circuits caused by contact with external conductors during use; (ii) to provide flexible structural support, the elastic modulus of PDMS is adjustable, and the patch is flexible; (iii) PDMS has good biocompatibility and meets the requirements of ISO10993 standard.

[0027] In this example, the electrode structure layer 11 includes a flexible dielectric film layer 110, an interdigitated electrode layer 111 formed on the front side of the flexible dielectric film layer 110, and a ground electrode layer 112 formed on the back side of the flexible dielectric film layer 110. The flexible dielectric film layer 110 is located between the interdigitated electrode layer 111 and the lower surface ground electrode layer 112. As the core element of dielectric elastic vibration, the material is preferably a polyimide (PI) film. Alternative materials include polyvinylidene fluoride (PVDF) film or other flexible polymer films with low dielectric loss and high breakdown field strength. Generally, the thickness of the PI film is 15-150 μm, preferably 25-100 μm. Specifically, the thickness of the PI film is 25 μm or 50 μm. The thickness of the PI film directly affects the acoustic resonant frequency and resonant efficiency; a thinner film produces a larger vibration amplitude under the same driving voltage. The interdigitated electrode layer 111 includes a first comb electrode s1 and a second comb electrode s2 arranged along the width of the facial application area, wherein the first comb electrode s1 and the second comb electrode s2 are staggered vertically or horizontally based on the contour of the facial application area and are spaced apart. The ground electrode layer 112 is a solid (unpatterned) metal layer deposited on the lower surface of the flexible dielectric film. The preferred material is Cr / Au (5-10 nm chromium adhesion layer + 50-200 nm gold conductive layer), but other high conductivity metals can also be used. The ground electrode layer is connected to the ground terminal (GND) of the driving circuit, forming a vertical electric field distribution between it and the interdigitated electrodes on the upper surface. The ground electrode layer 112 and the interdigitated electrodes constitute a normal electric field component along the normal of the piezoelectric layer.

[0028] Specifically, the first comb electrode s1 and the second comb electrode s2 are flexible electrodes, and are deposited or printed on the front side of the flexible dielectric thin film layer 110, respectively. The first comb electrode s1 includes a first comb back s10 arranged along the upper contour of the wide facial application area and multiple first comb teeth s11 arranged side by side on the first comb back s10; the second comb electrode s2 includes a second comb back s20 arranged along the lower contour of the wide facial application area and multiple second comb teeth s21 arranged side by side on the second comb back s20; wherein the first comb back s10 and the second comb back s20 are staggered vertically, and the first comb teeth s11 and the second comb teeth s21 alternate and are staggered. The width of the first comb teeth s11 and the second comb teeth s21 is 30-150 μm, preferably 70 μm; and the distance between the first comb teeth s11 and the second comb teeth s21 is 30-150 μm, preferably 70 μm. In short, the interdigitated electrode layer is deposited on the upper surface of a flexible dielectric film and consists of two sets of comb-like staggered metal electrodes. Each set of electrodes contains multiple parallel extending finger conductors, which are alternately interwoven in the two sets of electrodes. The electrode material is preferably Cr / Au (5-10 nm chromium adhesion layer + 50-200 nm gold conductive layer), but other high-conductivity metal materials (such as Al, Pt, Ag, etc.) can also be used. It is prepared by photolithography-metal deposition-lifting process or screen printing process. The total number of comb teeth can be set to 10-200 pairs according to the effective sound-generating area requirement. At the same time, two sets of interdigitated electrodes are connected to the positive terminal (or inverting terminal) of the AC drive signal, and the other set is connected to the negative terminal (or positive terminal) of the AC drive signal. A high-frequency AC voltage is applied between the two sets of electrodes to generate an alternating electrostatic field.

[0029] In some specific embodiments, the thickness of the back encapsulation layer 12 is 20-100 μm, and it provides insulation protection for the ground electrode 112 to form a mechanical transition interface at the coupling layer bonding surface.

[0030] In some specific embodiments, the coupling layer 2 is a biocompatible hydrogel coupling layer. The sound waves generated by the vibration of the flexible dielectric film layer 110 are transmitted to the biocompatible hydrogel coupling layer through the back encapsulation layer 112, and then to the skin via the hydrogel medium. The liquid components and intercellular fluid in the hydrogel form microbubbles under the negative pressure phase of the sound pressure fluctuations. These bubbles undergo stable volume oscillations during the sound wave cycle or violently collapse under high pressure. The cosmetic active substances loaded in the biocompatible hydrogel coupling layer diffuse into the epidermis and dermis through the microchannels of the stratum corneum under the permeation-enhancing effect of the bubbles. Bubble permeation enhancement includes the microjet effect, lipid bilayer perturbation, and acoustic flow effect. The microjet effect refers to the high-speed microjet generated by the asymmetric collapse of bubbles directly impacting the stratum corneum, forming transient microchannels. The lipid bilayer perturbation refers to the periodic pressure perturbation of the sound waves by the intercellular lipid bilayer of the stratum corneum, reducing diffusion resistance. The acoustic flow effect refers to the steady-state acoustic flow caused by the sound waves in the liquid promoting the convective transport of active substances into the skin. In other words, the oscillation and collapse (inertial cavitation) of bubbles (acoustic cavitation nuclei) produce the following effects to promote the transdermal penetration of active substances. Compared with the 1-5MHz of traditional cosmetic ultrasound and the mid-frequency ultrasound within 220kHz, the ultrasound within 20MHz of this scheme has a greater sound wave attenuation coefficient in the tissue, and the energy deposition is more concentrated within 2mm below the epidermis, matching the targeted delivery depth of cosmetic active substances (from the epidermis to the superficial dermis), while avoiding the excessive heating of deep tissues that may be caused by low-frequency ultrasound.

[0031] In this example, the biocompatible hydrogel coupling layer is a replaceable disposable component; the biocompatible hydrogel coupling layer is made of polyvinyl alcohol hydrogel, polyacrylamide hydrogel, or chitosan-based hydrogel; the thickness of the biocompatible hydrogel coupling layer is 0.2-2.0 mm. That is, the hydrogel coupling layer is a replaceable disposable component located between the lower PDMS encapsulation layer and the skin surface, and is detachably connected to the transducer patch body by physical adhesion or mechanical snap-fit. The hydrogel material is preferably polyvinyl alcohol (PVA) hydrogel, polyacrylamide (PAAm) hydrogel, or chitosan-based hydrogel, with a thickness of 0.2-2.0 mm. The core functions of the hydrogel coupling layer are: (i) to act as an acoustic coupling medium, filling the microscopic gap between the patch and the skin surface, and impedance matching to reduce sound reflection loss; (ii) to provide soft cushioning and improve wearing comfort; (iii) to selectively preload cosmetic active substances (such as hyaluronic acid, collagen, peptides, niacinamide, vitamin C derivatives, etc.), which are delivered to the skin layer 4 during use through ultrasound-assisted permeation.

[0032] In some specific embodiments, the driving circuit module 3 applies an AC voltage signal between the interdigitated electrode layer 111 and the ground electrode layer 112 to generate a periodic alternating electrostatic field between the two interlaced comb electrodes; and the alternating electrostatic field applies a periodic electrostatic force to the flexible dielectric film layer 110, driving the flexible dielectric film layer 110 to undergo periodic mechanical vibration at a frequency synchronized with the AC signal at the micrometer to nanometer scale.

[0033] In this example, the drive circuit module 3 is located on one edge or the back of the patch in a non-sound-generating area. The drive circuit module 3 (a conventional structure, not detailed here, and a directly purchased product) includes an adjustable duty cycle pulse width modulation controller, a signal generator, a power amplifier, and a battery. Specifically, the drive circuit module 3 outputs an AC drive signal with a frequency of 10-40MHz and a peak-to-peak voltage of 10-200V to the interdigitated electrodes. The drive circuit module 3 applies a high-frequency AC voltage signal (approximately 10-40MHz, preferably approximately 20MHz) between the interdigitated electrode layer 111 and the ground electrode layer 112, generating a periodic alternating electrostatic field between the alternating interdigitated electrode teeth. This alternating electric field applies a periodic electrostatic force (Maxwell stress) to the flexible dielectric film (PI) located between the interdigitated electrode layer and the ground electrode layer, driving the PI film to undergo periodic mechanical vibrations at a frequency synchronized with the AC signal, ranging from micrometers to nanometers in size. The drive circuit module is located on one edge or the back of the patch in a non-sound-emitting area and includes a miniature high-frequency signal generator, a power amplifier, and a coin cell battery (such as CR2032, 3V). The drive circuit outputs an AC drive signal with a frequency of 10-40MHz (preferably about 20MHz) and a peak-to-peak voltage of 10-200V to the interdigitated electrodes. The drive circuit may include a pulse-width modulation (PWM) control unit with an adjustable duty cycle to achieve an intermittent operating mode.

[0034] Combination Figures 2 to 4 As shown, the facial application areas include the nasolabial folds area, the eye area, and the forehead area. Specifically, in... Figure 2 In this design, the patch is presented in a strip / arc-shaped strip form, extending along the nasolabial fold, with a linear segmented IDE arrangement along the strip direction. When applied to the nasolabial fold area, the comb-shaped electrodes are alternately spaced on both sides, resulting in an effective sound-generating area of ​​1.5–4.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–70%, and a single treatment time of 10–20 min. In short, the arc-shaped strip + linear segmented IDE balances fit and acoustic field continuity, while conforming to the nasolabial fold surface to ensure uniform ultrasound coverage along the wrinkle direction. Figure 3In this device, the patch is arc-shaped / semi-circular, avoiding the area directly above the eyeball. The IDE (interface electrode) is sparsely arranged in an arc shape and applied to the area around the eyes (where the skin is thinnest and most sensitive, safety is paramount). The comb-shaped electrodes are alternately spaced up and down, with an effective sound-generating area of ​​0.8–2.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.5–2.0 mm, a duty cycle of 30–50%, and a single application time of 5–10 min; in short, it involves thickening the hydrogel buffer, reducing the voltage and duty cycle, shortening the application time, and using an arc shape to avoid the eyeball. Figure 4 In this device, the patch is sheet-shaped, rectangular, or arc-shaped, and may contain multiple unit arrays, distributed IDEs in multiple zones, or uniformly arranged. When applied to the forehead area, the patch is trapezoidal, with the comb-tooth electrodes alternating vertically. The effective sound-generating area is 3.0–8.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–80%, and a single treatment time of 10–20 minutes. In short, the nasolabial fold area has relatively thick skin (approximately 2 mm of epidermis + dermis), and the treatment goal is to improve wrinkles and promote deep penetration; it can withstand moderate to high ultrasound intensity. The skin around the eyes is the thinnest (approximately 0.5 mm) and has the highest sensitivity, requiring strict control of ultrasound power and treatment time to ensure safety. The forehead area is relatively flat, with a large area and moderate skin thickness, suitable for uniform coverage and longer treatment time. It also features a large-area, multi-zone array, allows for higher energy input, and can be expanded with multi-unit synergy; in other words, it has a large area, good skin tolerance, and prioritizes efficiency.

[0035] Combination Figure 5 As shown, this embodiment is based on the synergistic mechanism of dielectric acoustic resonance and acoustic cavitation-promoted infiltration, and its workflow is as follows: 1) Electrostatic drive generates mechanical vibration The driving circuit module applies a high-frequency AC voltage signal (frequency about 10-40MHz, preferably about 20MHz) between the interdigitated electrode layer and the ground electrode layer, generating a periodic alternating electrostatic field between the interdigitated electrode comb teeth. This alternating electric field applies a periodic electrostatic force (Maxwell stress) to the flexible dielectric film (PI) located between the interdigitated electrode layer and the ground electrode layer, driving the PI film to undergo periodic mechanical vibration at the micrometer to nanometer scale at a frequency synchronized with the AC signal.

[0036] 2) Acoustic resonance of dielectric thin film The mechanical vibration frequency of a PI film mainly depends on its thickness, Young's modulus, and density. When the driving frequency matches the intrinsic mechanical resonant frequency of the PI film, the film enters a resonant state, significantly amplifying the vibration amplitude and thus generating efficient acoustic wave output. Under optimized parameters (PI thickness 25-50 μm, IDE linewidth / spacing approximately 70 μm), the resonant frequency is approximately 20 MHz.

[0037] 3) Sound waves are coupled to the skin via hydrogel. The MHz-level sound waves generated by the vibration of the PI film are transmitted to the biocompatible hydrogel coupling layer through the lower PDMS encapsulation layer, and then transmitted to the skin surface through the hydrogel medium.

[0038] 4) Acoustic cavitation effect opens microchannels in the stratum corneum When MHz-level sound waves act on the skin surface through the hydrogel coupling layer, the liquid components in the hydrogel and the intercellular fluid form microbubbles (acoustic cavitation nuclei) in the negative pressure phase of the sound pressure fluctuation. These bubbles undergo stable volume oscillations (steady-state cavitation) or violent collapse under high pressure (inertial cavitation) in subsequent sound wave cycles. The oscillation and collapse of the bubbles produce the following effects to promote the transdermal penetration of active substances. 5) Transdermal delivery of active substances The cosmetic active substances (such as hyaluronic acid, peptides, collagen, niacinamide, etc.) loaded in the hydrogel coupling layer diffuse into the epidermis and dermis through the stratum corneum microchannels under the aforementioned acoustic cavitation-enhanced permeation mechanism, achieving highly efficient delivery. After the ultrasound is discontinued, the stratum corneum microchannels close naturally under the skin's own repair mechanism, without permanent damage.

[0039] In this example, the hydrogel, as an acoustic coupling medium, plays the following roles: (i) filling the microscopic gaps between the patch and the skin, eliminating acoustic impedance mismatch caused by the air layer; (ii) serving as an impedance transition layer for sound waves from the solid (patch) to soft tissue (skin); and (iii) acting as a carrier and release source for active substances. Bubble-induced penetration includes the microjet effect, lipid bilayer perturbation, and acoustic flow effect. The microjet effect refers to the high-speed microjet generated by the asymmetric collapse of bubbles directly impacting the stratum corneum, forming transient microchannels. Lipid bilayer perturbation refers to the periodic pressure perturbation of the lipid bilayer between stratum corneum cells by sound waves, reducing diffusion resistance. The acoustic flow effect refers to the steady-state acoustic flow caused by sound waves in the liquid promoting the convective transport of active substances into the skin. In other words, the oscillation and collapse (inertial cavitation) of bubbles (acoustic cavitation nuclei) produce the following effects to promote the transdermal penetration of active substances. Compared with the 1-5MHz of traditional cosmetic ultrasound and the mid-frequency ultrasound within 220kHz, the ultrasound within 20MHz of this scheme has a greater sound wave attenuation coefficient in the tissue, and the energy deposition is more concentrated within 2mm below the epidermis, matching the targeted delivery depth of cosmetic active substances (from the epidermis to the superficial dermis), while avoiding the excessive heating of deep tissues that may be caused by low-frequency ultrasound.

[0040] Furthermore, after each use, the disposable hydrogel coupling assembly should be removed from the reusable transducer patch and discarded. After cleaning the surface of the transducer patch, a new hydrogel coupling assembly can be attached for the next use. The transducer patch itself can be reused multiple times (e.g., 50-200 times), while the hydrogel assembly is a disposable hygiene consumable.

[0041] Therefore, this application has the following advantages: (1) Pure dielectric electrostatic drive without piezoelectric materials, that is, this scheme adopts an electrostatic drive structure of interdigitated electrodes + flexible dielectric film to replace the traditional piezoelectric ceramic drive, completely getting rid of the dependence on piezoelectric materials such as PZT, ZnO, AlN, etc., reducing the use of rare metals zirconium and titanium, simplifying the preparation process, reducing material costs, and avoiding the limitation of flexibility due to the inherent brittleness of piezoelectric ceramics. At the same time, by adopting a dielectric electrostatic drive mechanism to replace piezoelectric drive, the core structure of interdigitated electrodes + flexible dielectric film (such as polyimide PI) generates MHz-level ultrasonic output, fundamentally eliminating the dependence on piezoelectric materials, so that the thickness of the transducer patch can be controlled within 200μm, with better flexibility and wearability. (2) MHz-level high-frequency ultrasound is suitable for superficial transdermal permeation. That is, compared with the 1-5MHz of traditional cosmetic ultrasound and the ~220kHz of medium-frequency ultrasound, the ~20MHz ultrasound in this scheme has a larger sound wave attenuation coefficient in the tissue and the energy deposition is more concentrated in the 0-2mm range under the epidermis, matching the targeted delivery depth of cosmetic active substances (from the epidermis to the superficial dermis), while avoiding the excessive heating of deep tissues that may be caused by low-frequency ultrasound.

[0042] (3) The reusable transducer patch and disposable hydrogel have a separate structure, which breaks the design paradigm of the integrated transducer and mask substrate in the existing solution, making the core transducer component reusable (effectively reducing the cost per use to the level of hydrogel consumables). At the same time, the hygiene and safety of the skin contact surface are ensured by replacing the hydrogel each time. That is, the separate combination structure of the reusable flexible ultrasonic transducer patch and the disposable replaceable hydrogel component significantly reduces the cost per use while ensuring hygiene and safety, and at the same time reduces the generation of electronic waste.

[0043] (4) Localized design with one policy for each area: This solution actively identifies the differences in skin thickness, curvature, sensitivity and care goals of the three facial areas of nasolabial folds, eye area and forehead. The shape of the patch, IDE density, driving power and action time are independently customized, which achieves more precise and safer local care than the uniform solution for the whole face. In particular, the ultrasound intensity and duration are strictly controlled in the eye area to ensure safe use. Therefore, by designing the patch shape, hydrogel thickness, interdigitated electrode distribution density, effective sound area, driving frequency and power differently for the three different local facial areas of nasolabial folds, eye area and forehead, precise local care with one policy for each area is achieved.

[0044] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance, comprising an ultrasound-enhanced permeation patch, a coupling layer, and a driving circuit module, wherein the ultrasound-enhanced permeation patch comprises a front encapsulation layer, an electrode structure layer, and a back encapsulation layer arranged sequentially, and the coupling layer is adhered to the back encapsulation layer, characterized in that: The thickness of the ultrasonic permeation-enhancing patch is less than 200 mm; the electrode structure layer includes a flexible dielectric film layer, an interdigitated electrode layer formed on the front side of the flexible dielectric film layer, and a ground electrode layer formed on the back side of the flexible dielectric film layer, wherein the ground electrode layer and the interdigitated electrodes constitute a normal electric field component along the piezoelectric layer normal direction, and the interdigitated electrode layer includes a first comb electrode and a second comb electrode arranged along the width direction of the facial application area, wherein the first comb electrode and the second comb electrode are arranged alternately and vertically or horizontally based on the contour of the facial application area. The driving circuit module applies an AC voltage signal between the interdigitated electrode layer and the ground electrode layer to generate a periodic alternating electrostatic field between the two interlaced comb electrodes; and the alternating electrostatic field applies a periodic electrostatic force to the flexible dielectric film layer, driving the flexible dielectric film layer to undergo periodic mechanical vibration at the micron to nanometer scale at a frequency synchronized with the AC signal. The coupling layer is a biocompatible hydrogel coupling layer. The sound waves generated by the vibration of the flexible dielectric film layer are transmitted to the biocompatible hydrogel coupling layer through the back encapsulation layer, and then to the skin through the hydrogel medium. The liquid components in the hydrogel and the intercellular fluid form microbubbles in the negative pressure phase of the sound pressure fluctuation. The bubbles undergo stable volume oscillations or violently collapse under high pressure during the sound wave cycle. The cosmetic active substances loaded in the biocompatible hydrogel coupling layer diffuse into the epidermis and dermis through the microchannels of the stratum corneum under the permeation promotion of the bubbles.

2. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: Bubble-induced penetration includes microjet effect, lipid bilayer perturbation, and acoustic flow effect. The microjet effect refers to the high-speed microjet generated by the asymmetric collapse of bubbles directly impacting the stratum corneum, forming transient microchannels. The lipid bilayer perturbation refers to the periodic pressure perturbation of the lipid bilayer between stratum corneum cells by sound waves, reducing diffusion resistance. The acoustic flow effect refers to the steady-state acoustic flow caused by sound waves in liquids promoting the convective transport of active substances into the skin.

3. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The first comb electrode includes a first comb back arranged along the upper contour of the wide facial application area and multiple first comb teeth arranged side by side on the first comb back; the second comb electrode includes a second comb back arranged along the lower contour of the wide facial application area and multiple second comb teeth arranged side by side on the second comb back; wherein the first comb back and the second comb back are staggered vertically, and the first comb teeth and the second comb teeth alternate and are staggered; and / or, the first comb electrode and the second comb electrode are flexible electrodes, and are respectively deposited or printed on the front side of a flexible dielectric film layer; and / or, the width of the first comb teeth and the second comb teeth is 30-150μm, and the spacing between the first comb teeth and the second comb teeth is 30-150μm.

4. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The flexible dielectric film layer is a polyimide film, a polyvinylidene fluoride film, or other flexible polymer films with low dielectric loss and high breakdown field strength; and / or, The thickness of the flexible dielectric thin film layer is 15-150 μm.

5. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The grounding electrode layer is a full-surface metal layer deposited on the lower surface of a flexible dielectric film.

6. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The biocompatible hydrogel coupling layer is a replaceable disposable component; and / or, the biocompatible hydrogel coupling layer is a polyvinyl alcohol hydrogel, polyacrylamide hydrogel, or chitosan-based hydrogel; and / or, the thickness of the biocompatible hydrogel coupling layer is 0.2-2.0 mm.

7. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The driving circuit module is located on one side edge or the back of the patch in a non-sound-emitting area, and the driving circuit module includes an adjustable duty cycle pulse width modulation controller, a signal generator, a power amplifier and a battery; and / or, the driving circuit module outputs an AC driving signal with a frequency of 10-40MHz and a peak-to-peak voltage of 10-200V to the interdigitated electrodes.

8. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The thickness of the front encapsulation layer is 50-200μm; the front encapsulation layer provides electrical insulation protection and flexible support for the electrode structure layer, and the material is polydimethylsiloxane.

9. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to claim 1, characterized in that: The thickness of the back encapsulation layer is 20-100 μm, and it provides insulation protection for the ground electrode to form a mechanical transition interface at the interface of the biocompatible hydrogel coupling layer.

10. The localized facial ultrasound-enhanced permeation patch structure based on flexible dielectric acoustic resonance according to any one of claims 1 to 9, characterized in that: The facial application areas include the nasolabial fold area, the area around the eyes, and the forehead area. When applying to the nasolabial fold area, the contour of the application area extends along the nasolabial groove. The comb-shaped electrodes alternate between left and right, with an effective sound-emitting area of ​​1.5–4.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–70%, and a single application time of 10–20 min. It is applied to the periorbital area, with the facial application area avoiding direct contact with the eyes. The comb-shaped electrodes are alternately spaced, and the effective sound-generating area is 0.8–2.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.5–2.0 mm, a duty cycle of 30–50%, and a single application time of 5–10 min. It is applied to the forehead area, with the facial application area in a trapezoidal shape. The comb-shaped electrodes are alternately spaced, and the effective sound-generating area is 3.0–8.0 cm². 2 The biocompatible hydrogel coupling layer has a thickness of 0.3–1.0 mm, a duty cycle of 50–80%, and a single interaction time of 10–20 min.

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