Multi-phase radio frequency treatment system for reducing or eliminating radio frequency microneedle pinpoint erythema

Abstract

The present application belongs to the technical field of medical equipment, and discloses a multi-phase radio frequency treatment system for reducing or eliminating radio frequency microneedle punctiform erythema. The system comprises a three-phase radio frequency generator and a microneedle electrode array, the generator outputs three-phase signals, each phase signal has the same frequency and amplitude and a phase difference of 120°; the microneedles of the microneedle electrode array are divided into three phase groups A, B and C, and each group contains at least one microneedle in any local area. When the system works, a rotating electric field is excited under the skin to make the energy uniformly distributed, thereby reducing or eliminating punctiform erythema. Clinical tests show that the present application reduces the incidence of erythema by more than 90% and shortens the duration to within 1 hour.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more specifically, to a multiphase radiofrequency therapy system for reducing or eliminating radiofrequency microneedle erythema. Background Technology

[0002] Radiofrequency microneedling combines microneedle puncture and radiofrequency energy heating. By inserting tiny microneedles into the skin, radiofrequency energy is released in the dermis to stimulate collagen regeneration and remodeling. It is widely used clinically to treat skin problems such as acne scars, enlarged pores, and facial wrinkles.

[0003] However, clinical observations show that radiofrequency microneedling treatment may be accompanied by a series of skin reactions. In addition to common transient erythema and edema, there is also a special type of postoperative reaction: immediately after treatment, punctate erythema or reticular (sieve-like) erythema may appear on the skin surface, consistent with the distribution of the needle holes. This erythema is usually distributed in an array, corresponding to the location of the microneedle puncture.

[0004] Existing research indicates that such punctate erythema is not uncommon. A systematic review of the safety of microneedling treatment clearly states that punctate or reticular (sieve-like) erythema is one of the potentially persistent and serious adverse events following microneedling. Although these reactions are not life-threatening complications, their regular shape and orderly arrangement contrast sharply with the normal skin before treatment, severely affecting the aesthetics of the treated area and potentially lasting for weeks to months, causing significant psychological distress to users. If the user's skin has poor repair capabilities, the erythema may persist for more than 5 days, increasing the risk of post-inflammatory hyperpigmentation (PIH), especially common in people with darker skin tones.

[0005] Regarding its causes, see reference... Figure 7 Existing research indicates that such reactions are closely related to uneven distribution of radiofrequency energy and excessive energy concentration around the needle tip. When energy is concentrated near the needle tip, independent hot spots form around each needle tip, leading to excessive local tissue reaction, ultimately manifesting as punctate erythema corresponding to the needle point location. It is noteworthy that there is currently no standardized treatment for these adverse reactions. Some literature reports the use of combination therapies such as LED phototherapy and salicylic acid peels to treat this problem, but the recovery period is as long as 6 months.

[0006] Therefore, how to change the energy distribution mode from the physical mechanism level, achieve energy uniformity, avoid energy concentration from the root, and realize the intrinsic uniform distribution of radio frequency energy in the action area of ​​the microneedle array, thereby reducing or eliminating the dot-like red spots consistent with the morphology of the microneedle array, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to provide a multiphase radiofrequency therapy system for reducing or eliminating radiofrequency microneedle punctate erythema. This invention utilizes a multiphase radiofrequency generator in synergy with a microneedle electrode array with a specific phase layout to excite a rotating electric field in the subcutaneous tissue, achieving an intrinsically uniform energy distribution. This significantly reduces or eliminates punctate erythema consistent with the microneedle array morphology after radiofrequency microneedle application to the skin.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a multiphase radiofrequency ablation system for reducing or eliminating radiofrequency microneedle erythema, comprising: A multiphase radio frequency generator is configured to output M-phase radio frequency signals, where M=3, and each phase signal has the same frequency and amplitude. The phase difference of the M-phase signals output by the multiphase radio frequency generator is 360° / M. The microneedle electrode array includes multiple microneedles, which are divided into M phase groups. The microneedles in each phase group are electrically connected, and the phase group distribution of the multiple microneedles satisfies the following condition: in any local area composed of adjacent microneedles, there is at least one microneedle containing each phase group. The microneedles of the M phase groups of the microneedle electrode array are connected to the M phase output terminals of the multiphase radio frequency generator. When the multiphase radio frequency generator outputs the M-phase signal, a rotating electric field is excited in the subcutaneous tissue corresponding to the microneedle electrode array, avoiding the formation of an energy concentration area in the skin tissue that is consistent with the shape of the microneedle array, thereby reducing or eliminating the punctate erythema.

[0009] Preferably, when multiple microneedles are arranged in a rectangular pattern, in any 3×3 local area composed of adjacent microneedles, each row and each column of the 3×3 area contains one microneedle of each of the three phases.

[0010] By adopting the above technical solution, any group of four adjacent microneedles includes three microneedles with different phases and one microneedle with the same phase as the diagonal microneedle, thus forming two sets of three-phase local regions. The triangular regions enclosed by the different three-phase microneedles synthesize a single electric field vector from the three signals. This vector has a constant amplitude and rotates uniformly in the plane with time. Compared with other arrangements such as rhombuses and hexagons, the rectangular arrangement makes it easier to achieve a complete, non-overlapping, and fully heated skin treatment effect when applying needles to the user. At the same time, in the isosceles right-angled triangular splicing array, the triangle type of the entire array is consistent, the rotation field shape is uniform (all in the same elliptical direction), the average heating power density of the entire array is equal everywhere, and the temperature rise rate is consistent, forming a macroscopically uniform thermal field. At the unit boundary of the rectangular array, the horizontal components of the electric field cancel each other out, and the vertical components superimpose, so the time-averaged power of the synthesized field is exactly equal to the heating power inside the unit. Therefore, the heating efficiency at the boundary is consistent with that inside the unit, and there is no energy abrupt change caused by splicing. However, the standard treatment head shape in the medical aesthetics field is almost always rectangular or square (due to limitations in skin flatness and scanning path). If rhomboid or regular hexagonal honeycomb arrays are used for rectangular treatment surfaces, the equilateral triangular structure at the boundary must be changed (compressed or stretched), resulting in a circular rotating field in the center of the array and an elliptical rotating field at the boundary. The rotating field morphology of each region is different, and the average heating power density varies. After heating for a certain period of time, temperature differences are generated in different regions, and the uniformity of the macroscopic thermal field decreases.

[0011] Preferably, the multiphase radio frequency generator includes a programmable logic control unit and a programmable multiphase phase modulation module, wherein the programmable multiphase phase modulation module is configured to output a multiphase signal having the 360° / M phase difference according to the instructions of the programmable logic control unit.

[0012] Preferably, the programmable multiphase phase modulation module is implemented using direct digital frequency synthesis technology, and its internal components include a phase accumulator and a phase control word register.

[0013] Preferably, the radio frequency signal output by the multiphase radio frequency generator meets the following operating conditions: the duration of a single output is 20ms to 80ms, and the total output power is 5W to 40W.

[0014] Preferably, the total output power is 12W, and the duration of a single output is 60ms.

[0015] Preferably, the microneedle meets the following condition: the depth of the microneedle penetrating the skin is 0.5 mm to 3.0 mm.

[0016] Preferably, the depth to which the microneedles penetrate the skin is 1.5 mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Preventing energy concentration at the source: This invention achieves intrinsically uniform heating at the electric field level through a rotating electric field, distributing energy evenly across the area surrounded by multiple microneedles, rather than concentrating it around the needle tip. This uniform energy distribution fundamentally avoids overheating of the tissue around a single needle tip, thereby eliminating the physical basis for the formation of punctate erythema.

[0018] 2. Significantly reduced incidence: Preliminary clinical trials show that using this invention, the incidence of punctate erythema consistent with the microneedle array morphology is reduced by more than 90% compared with the traditional monophasic method, and the mild erythema that appears also subsides rapidly within 1 hour.

[0019] 3. Accelerates postoperative recovery: By avoiding local hot spots and excessive inflammatory response, the duration of erythema after application to the skin is significantly shortened, allowing users to resume normal social activities more quickly. Attached Figure Description

[0020] Figure 1 The overall module composition diagram of the multiphase active phase-controlled radio frequency generator of the present invention shows the connection relationship between the programmable logic control unit, the multiphase modulation module, and the multi-channel power module. Figure 2 A schematic diagram of a single RF power channel, showing the sequential connection relationship of the half-bridge MOSFET driver module, RF conversion module, RF power transformer and impedance matching module; Figure 3 : A schematic diagram of the output of a multiphase RF generator in three-phase output mode, showing that the phase difference between the three-phase signals A, B, and C is 120°; Figure 4 The schematic diagram of the phase layout of the 25-pin three-phase microneedle electrode array in Embodiment 1 of the present invention shows the three-phase cyclic arrangement rule in the 5*5 matrix; Figure 5 The schematic diagram of the phase layout of the 49-needle three-phase microneedle electrode array in Embodiment 2 of the present invention shows the three-phase cyclic arrangement rule in the 7*7 matrix; Figure 6 Schematic diagram of a single-phase radio frequency source and bipolar electrodes; Figure 7 : Schematic diagram of current density distribution in subcutaneous tissue using bipolar microneedles, showing that energy is concentrated around the needle tip; Figure 8 : A schematic diagram of the multiphase radiofrequency therapy system of the present invention, showing the connection between the multiphase radiofrequency generator and the microneedle electrode array; Figure 9 The schematic diagram (three-phase) of the principle of the rotating electric field formed in the subcutaneous tissue during the operation of the system of the present invention shows the trajectory of the end of the synthesized vector within the triangular region enclosed by adjacent A, B, and C electrodes; Figure 10: Curves showing the change of punctate erythema scores over time for two groups of users; Figure 11 Bar chart comparing the duration of erythema between two groups of users; Figure 12 Bar chart comparing the user satisfaction scores of the two groups. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In existing technologies, monopolar electrodes require the use of an external negative electrode plate, resulting in a deep but uncontrollable current penetration path. For example... Figure 6 As shown, although bipolar or multipolar electrodes concentrate the electrodes in the treatment head, the current path is limited to between the positive and negative electrodes. However, as... Figure 7 As shown, regardless of the electrode arrangement, since all electrodes are connected to a single-phase radio frequency source, the electric field distribution characteristics determine that the energy is most concentrated in the area near the electrodes. In microneedling therapy, this results in an independent hot spot around each needle tip, while the heating in the inter-needle area is relatively insufficient. The non-uniformity of energy distribution directly affects the controllability and consistency of the treatment effect, and differences in heating intensity may occur within the treatment area, affecting the overall treatment quality and aesthetics.

[0023] Ultimately, the problem stems from the fact that the electric field generated by a single-phase power supply and a combination of monopolar / bipolar electrodes can only vibrate in one direction in space, failing to create uniform volumetric heating. Although there are electrodes on the market that arrange microneedles into a matrix, they are essentially simple replicas of multiple monopolar or bipolar units, without changing the physical characteristic that energy is concentrated near the needle tip, and thus cannot fundamentally solve the problem of uneven heating.

[0024] Example 1: Tri-phase radiofrequency ablation system (25 needles) This embodiment provides a triphase radiofrequency therapy system, including a triphase active phased radiofrequency generator and a 25-needle triphase microneedle electrode array.

[0025] 1. System Composition (1) Multiphase radio frequency generator The three-phase active phase-controlled radio frequency generator used in this embodiment has the following core architecture: Figure 1 As shown, it includes: Programmable Logic Control Unit (CPLD): As the core control component, it employs a CPLD programmable gate array device and is responsible for top-level control logic, parameter configuration, and status monitoring. The CPLD, together with the auxiliary power supply module and the RF detection module, forms a closed loop. Based on the RF electrical parameters fed back by the RF detection module, it adjusts the amplitude of the adjustable DC bus voltage output by the auxiliary power supply module to maintain the consistency of output power in each phase and the stability of the total output power when the load changes.

[0026] Radio frequency bus voltage generation module (DC / DC): Connected to a programmable logic control unit, it provides an adjustable DC bus voltage (VBUS) according to control commands, with a voltage range of DC5-90V; Programmable Frequency Signal Module (DDS): Uses a crystal oscillator as the clock source and internally employs frequency multiplication and phase-locked loop technology and a high-precision frequency divider circuit to generate an RF reference frequency. The programmable logic control unit writes the frequency division coefficients to it through the IIC interface to generate the required reference RF frequency signal (preferably 1MHz in this embodiment).

[0027] Programmable multiphase phase modulation module: Connected to the programmable logic control unit and the programmable frequency signal module. This module is the core of this generator, used to receive a reference RF frequency signal and generate M sets (M=3 in this embodiment) of independent, phase-adjustable complementary control signals. In this embodiment, this module is specifically implemented using digital logic circuits based on DDS (Direct Digital Synthesis) technology. Internally, it includes a phase accumulator, a phase control word register, and a multi-channel waveform generator. The programmable logic control unit writes a phase control word representing the target phase difference to the phase control word register via an internal bus. The phase difference adjustment accuracy can reach within 1°, and the adjustment range is 0° to 180° (for example, to achieve a 120° phase difference, a control word corresponding to 120.0° is written). The phase accumulator uses a reference clock as a reference and generates an address with a corresponding phase offset based on the phase control word, driving the multi-channel waveform generator to simultaneously output M sets of precisely phased complementary control signals. When this embodiment operates in three-phase mode, as... Figure 3 As shown, the programmable multiphase phase modulation module outputs three sets of complementary control signals, corresponding to phase A, phase B and phase C respectively, with a phase difference of 120° (i.e., phase A 0°, phase B 120°, and phase C 240°).

[0028] The programmable logic control unit (PLC) can send a latch enable signal to the phase control word register, placing the register in a locked state. In the locked state, the phase control word register is configured to block write operations to its stored contents. This write blocking function is coupled to the latch enable signal—that is, the register only resumes responding to write operations after the latch enable signal is released. Once the phase control word is written to the phase control word register and locked, it remains constant throughout the entire RF output process, and the phase difference cannot be dynamically adjusted. However, if the phase control word needs to be reset between different treatments or different usage scenarios, the RF output must be stopped, the register unlocked, and a new phase control word rewritten and locked before the next RF output.

[0029] Multiple RF power channels: This includes M (M=3 in this embodiment) independent and structurally identical RF power channels, labeled as phase A, phase B, and phase C power modules, respectively. Each RF power channel is uniquely connected to a set of complementary control signals of a programmable multiphase phase modulation module, used to independently convert the input DC bus voltage into the corresponding phase of RF power output.

[0030] like Figure 2 As shown, each RF power channel contains, in sequence: ① Half-bridge MOS transistor driver module: Receives a pair of complementary drive signals from the programmable multiphase phase modulation module to drive the subsequent RF conversion module.

[0031] ②RF conversion module: It adopts a half-bridge LCC resonant circuit to convert the input rectangular square wave into a sine wave energy output of the same frequency.

[0032] ③RF power transformer and impedance matching module: Increases output voltage, improves RF power output, and provides electrical isolation between secondary circuits and user application circuits, increasing safety.

[0033] ④ Impedance matching module: Composed of an RC network and controlled by a programmable logic control unit, it is used to match the dynamic impedance of human skin (usually tens to hundreds of ohms) so that radio frequency energy can be input into the skin to generate Joule heat to the maximum extent.

[0034] Auxiliary power supply module: connected to the bus voltage input terminal of the programmable logic control unit and each RF power channel, used to uniformly supply power to M RF power channels under an adjustable DC bus voltage (in this embodiment, the voltage range is DC 5-90V, preferably 50V).

[0035] The radio frequency (RF) detection module includes an RF voltage detection module, an RF current detection module, a skin impedance detection module, and an RF energy integration module. It uses high-precision current and voltage transformers to sample the RF voltage and current signals output from each phase channel in real time. The sampled signals are rectified and converted into digital quantities by an ADC, then fed back to the main control module via an SPI interface for software-level PID closed-loop control, energy accumulation calculation, and system operation status monitoring.

[0036] Communication interface module: Connects to the programmable logic control unit and is used for data exchange with external systems.

[0037] The workflow of a multiphase RF generator includes: Initialization: Power on the main control module, configure the programmable clock module, and set the RF base frequency to 1MHz.

[0038] Parameter settings: The main control module writes parameters such as working mode (three-phase) and target phase difference (120°) to the CPLD.

[0039] Energy preparation: The main control module is equipped with an auxiliary power supply module, and the DC bus voltage is set to 50V.

[0040] Synchronous output: The CPLD generates three pairs of complementary drive signals with a phase difference of 120°, which are sent to the three power channels respectively.

[0041] Power conversion: The three channels operate independently, outputting a 1MHz high-voltage sine wave with a phase difference of 120°.

[0042] Real-time monitoring and closed-loop control: The RF detection module provides real-time feedback on the parameters of each channel, and the main control module uses this feedback to perform closed-loop adjustment of the total output voltage of the auxiliary power module to maintain the system's set output power.

[0043] The parameters of the multiphase RF generator are set using the following steps: Step S1: Determine the output parameters Based on treatment needs, determine the target frequency f, number of output phases M, and maximum output power P_max of the radio frequency output.

[0044] Step S2: Configure the programmable frequency signal module The programmable logic control unit calculates the division factor of the programmable frequency signal module based on the target frequency f: division factor = base frequency / f. For example, if the base frequency is 100MHz and the target frequency is 1MHz, then the division factor is 100.

[0045] Step S3: Configure the programmable multiphase phase modulation module The programmable logic control unit determines the number of half-bridge drive groups to be activated and the phase difference based on the target number of phases M, and sets the phase difference according to the treatment requirements. For example, when M=3, three sets of complementary drive signals are activated with a phase difference of 120° to construct a rotating electric field.

[0046] Step S4: Configure RF bus voltage The programmable logic control unit calculates the required RF bus voltage V_bus based on the target maximum output power P_max and the load impedance range. Simultaneously, based on V_bus and the maximum output power, it ensures that the power devices (MOSFETs, transformers, resonant capacitors) of the RF converter module operate within safe limits.

[0047] Step S5: Configure the detection module range The programmable logic control unit calculates the maximum output current I_max and the maximum output voltage V_max based on P_max and the load impedance range, and configures the range of the RF voltage detection module and the RF current detection module to ensure detection accuracy.

[0048] Step S6: Start output After completing the above configuration, the multiphase RF generator begins operation according to the set parameters. The programmable logic control unit performs closed-loop control of the output voltage of the auxiliary power module based on the feedback signal to maintain the stability of the output power of each phase.

[0049] (2) Microneedle electrode array The 25-pin three-phase microneedle electrode array used in this embodiment, such as Figure 4 As shown, the array includes an insulating substrate made of PC-HP2NR material with a thickness of 2mm and an overall size of 11mm*11mm.

[0050] Twenty-five microneedles are fixedly arranged in a 5x5 matrix on an insulating substrate. Each microneedle is made of conductive metal, with a diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.95 mm between adjacent microneedles.

[0051] The 25 microneedles are divided into three phase groups, A, B, and C, and are arranged in a cyclical sequence of "ABC", periodically distributed in both row and column directions, as shown in Table 1. Table 1: Schematic diagram of the phase layout of a 25-needle three-phase microneedle electrode array (and...) Figure 4 correspond)

[0052] With this layout, in any 3*3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases.

[0053] All microneedles marked as phase A are electrically connected to a common phase A input terminal via internal wires. Similarly, phase B and phase C microneedles are connected to their respective phase B and phase C input terminals. These three input terminals (A, B, and C) are the external interfaces of this microneedle electrode array, used to connect one-to-one with the three phase output terminals of an external multiphase RF generator.

[0054] 2. System Connection and Collaborative Working Principle like Figure 8 As shown, the three input terminals (A, B, C) are connected one-to-one to the three phase output terminals of a three-phase active phase-controlled RF generator via a multi-pin connector (e.g., an FPC connector). The RF generator operates in three-phase mode with a phase difference set to 120°. This method allows the multiphase signals output by the generator to be precisely distributed to the corresponding microneedles according to the phase layout of the electrode array.

[0055] When the system is operating, the three-phase RF generator outputs three-phase signals with a frequency of 1MHz, equal amplitude, and a phase difference of 120°. These signals are transmitted to the corresponding phase groups of the microneedle electrode array via connecting lines. Due to the regular phase layout of the electrode array, adjacent A, B, and C phase microneedles are arranged in a triangular pattern in space.

[0056] like Figure 9 As shown, within the triangular region enclosed by adjacent A, B, and C phase microneedles, the three signals synthesize into a rotating electric field vector. This vector has a constant amplitude and rotates uniformly with time. For the local region formed by the three microneedles with different phases, the trajectory is circular when the electrodes are distributed in an equilateral triangle, and elliptical in an isosceles triangular layout.

[0057] The heating of biological tissues (Joule heating) depends on the square of the electric field strength. The average time value.

[0058] Inside the three-phase microneedle unit A, B, and C: the rotational field amplitude remains constant. The time-averaged power is .

[0059] In a rectangular array, adjacent triangular units are joined in a mirror image manner, with their internal rotating electric fields rotating in opposite directions. Therefore, at the shared boundary, the horizontal components of the two electric fields cancel each other out, while their vertical components superimpose. The resulting field becomes... .

[0060] Calculate the time-averaged power:

[0061] Therefore, when multiple triangles are joined together, the time-averaged heating power at the boundary is exactly equal to the heating power inside the unit. In terms of average heating efficiency per unit time, the heating efficiency at the boundary remains consistent with that inside the unit; there is no sudden energy change due to the joining process, and the heat generation at the electric field boundary is consistent with the heat generation in other regions.

[0062] When tri-phase microneedles are arranged in a rectangular array within any 3x3 local area composed of adjacent microneedles, with each row and column containing one microneedle from each of the three phases, compared to other arrangements such as rhombuses and hexagons, it is easier to achieve a complete, non-overlapping, and thorough heating effect on the rectangular treatment area during acupuncture. Furthermore, in an isosceles right-angled triangular array, the entire array has a consistent triangle type and a uniform rotational field shape (all in the same elliptical direction), resulting in a uniform average heating power density and consistent temperature rise rate, forming a macroscopically uniform thermal field. In contrast, if rhombus or regular hexagonal honeycomb arrays are used on a rectangular treatment surface, the equilateral triangular structure at the boundaries must be altered (by compression or stretching), resulting in a circular rotational field at the center and an elliptical rotational field at the boundaries. This leads to different rotational field shapes in different areas, resulting in variations in average heating power density. After a certain heating time, temperature differences arise in different areas, reducing the uniformity of the macroscopic thermal field.

[0063] From a signal flow perspective, the generator's programmable multiphase phase modulation module first generates three pairs of complementary drive signals based on the phase control word set by the programmable logic control unit (corresponding to a 120° phase difference). These three pairs of signals are independently amplified by three structurally identical RF power channels and then transmitted to the A, B, and C phase input terminals of the electrode array via FPC connectors. Since the three power channels share the same adjustable DC bus voltage and have identical structures, the amplitudes of the three output signals naturally remain consistent, requiring no additional amplitude calibration. The phase layout of the electrode array (ABC cyclic arrangement) causes adjacent A, B, and C phase microneedles to be triangularly distributed, matching the 120° time phase difference of the generator output.

[0064] The rotating electric field drives charged particles in the skin tissue to move in eddy currents, generating uniform Joule heating in the area between the microneedles, forming a "radiofrequency eddy current region". The entire treatment surface is seamlessly connected by multiple such microscopic eddy current regions, achieving macroscopically uniform heating.

[0065] Example 2: Tri-phase radiofrequency ablation system (49 needles) This embodiment provides another tri-phase radiofrequency therapy system, whose multi-phase radiofrequency generator is the same as that in Embodiment 1, except that it uses a 49-pin tri-phase microneedle electrode array.

[0066] 1. Microneedle electrode array The 49-pin three-phase microneedle electrode array used in this embodiment, such as Figure 5 As shown, the array includes an insulating substrate made of PC-HP2NR material with a thickness of 2mm and an overall size of 11mm*11mm.

[0067] Forty-nine microneedles are fixedly arranged in a 7x7 matrix on an insulating substrate. Each microneedle is made of a conductive metal (such as stainless steel, titanium alloy, or gold-plated copper alloy), with a needle diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.25 mm between adjacent microneedles.

[0068] The 49 microneedles are divided into three phase groups, A, B, and C, and are arranged in a cyclical sequence of "ABC", periodically distributed in both row and column directions, as shown in Table 2. Table 2: Schematic diagram of the phase layout of the 49-needle three-phase microneedle electrode array

[0069] With this layout, in any 3*3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases.

[0070] 2. System Connection and Collaborative Working Principle Connect the A, B, and C phase input terminals of the 49-pin electrode array to the A, B, and C phase output terminals of the three-phase RF generator, respectively. When the system is working, the generator outputs a 1MHz, 120° phase difference three-phase signal, which excites a rotating electric field in the triangular region formed by the adjacent A, B, and C phase microneedles.

[0071] Compared to a 25-pin array, a 49-pin array creates a denser micro-vortex region, further enhancing the precision of heating.

[0072] Experimental Example 1: Clinical Application Validation To verify the effectiveness of the system of the present invention in reducing punctate erythema, the applicant conducted an exploratory clinical trial.

[0073] 1. Experimental Design Subjects: A total of 60 users aged 30-55 years with facial skin aging and a need for radiofrequency microneedling treatment were enrolled. They included Fitzpatrick skin types II-IV, and the distribution of each type was basically balanced.

[0074] Grouping and Control: A self-controlled half-face design was used, with each subject's face randomly divided into two sides. The experimental side used the tri-phase radiofrequency treatment system (25-needle tri-phase array) described in Example 1 of this invention, while the control side used a traditional mono-phase radiofrequency microneedle system (the same 25-needle array but with a mono-phase signal applied).

[0075] Treatment parameters: Output phase count: Three-phase (test side); Single-phase (control side); Phase difference: The experimental side is set to 120° (i.e., phase A 0°, phase B 120°, phase C 240°); the control side is 0°. Output frequency: 1MHz; Total output power: 12W; Pulse duration: 60ms; Microneedle insertion depth: 1.5mm.

[0076] Treatment plan: 3 treatments per side, with an interval of 1 month.

[0077] Control group parameters: The same number of pins array was used, but a single-phase signal was applied. Other parameters were the same as those of the experimental group.

[0078] Evaluation criteria: Two independent dermatologists clinically scored the punctate erythema immediately after treatment, at 1 hour, 24 hours, and 7 days after treatment (0-3 point scale: 0 = no erythema, 1 = mild punctate, 2 = moderate punctate, 3 = severe punctate).

[0079] Secondary metrics: duration of erythema (hours), user satisfaction score (1-10 points), and safety assessment (pain VAS score, adverse event record).

[0080] Experimental results: 2.1 Punctate erythema score, reference Figure 10 :

[0081] 2.2 Duration of erythema, reference Figure 11 : Experimental group: The average duration of erythema was 0.8 ± 0.3 hours; Control group: The average duration of erythema was 4.2 ± 1.3 days (approximately 100 hours). The duration of erythema in the experimental group was shortened by more than 99% compared with that in the control group.

[0082] 2.3 User satisfaction, reference Figure 12 : Experimental group: The average user satisfaction score was 9.2 / 10; Control group: The average user satisfaction score was 6.1 / 10.

[0083] 2.4 Security Assessment: During the treatment, no serious adverse events such as burns, infections, or blisters occurred in either group of users.

[0084] Experimental group: Users occasionally experienced transient mild pain during treatment (average VAS score 2.1±0.5), and transient uniform erythema appeared immediately after treatment. All of these symptoms subsided spontaneously within 1 hour. No other skin reactions other than punctate erythema were observed.

[0085] Control group: In addition to punctate erythema, mild edema was occasionally observed (12 cases, 20%), all of which subsided spontaneously within 24 hours; some users (8 cases, 13.3%) experienced significant pain during treatment (VAS score average 4.3±0.8).

[0086] All adverse reactions were mild and reversible, requiring no special treatment and not affecting subsequent treatment. 3. Typical cases, Case 1: Female, 42 years old, Fitzpatrick skin type III, with facial skin laxity. The left side of the face was treated with the method of this invention, while the right side was treated with the traditional monophasic method. Immediate post-treatment observation: Left side (side of the invention): The skin is slightly and evenly red, with no visible punctate erythema; Right side (control side): Obvious punctate erythema consistent with the microneedle array morphology appears, distributed in a grid pattern.

[0087] One hour later, at the follow-up visit, the skin on the left side had largely returned to its normal color, while the right side still showed obvious punctate erythema. Twenty-four hours later, at the follow-up visit, the left side had completely recovered, while the right side still showed obvious erythema.

[0088] 4. Experimental Conclusions Clinical trial results show that using the multiphase radiofrequency treatment system described in this invention (especially the triphase 120° configuration, 12W power, 60ms pulse width, and 1.5mm depth) for skin treatment can significantly reduce or eliminate punctate erythema consistent with the microneedle array morphology after radiofrequency microneedling treatment. Compared with traditional monophase systems, this system reduces the incidence of punctate erythema by more than 90% (only 8.3% of patients experience mild punctate erythema), shortens the duration of erythema to less than 1 hour, and significantly improves user satisfaction. This effect is attributed to the fact that this system achieves intrinsically uniform energy distribution through a rotating electric field, fundamentally avoiding energy concentration around the needle tip.

[0089] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multiphase radiofrequency therapy system for reducing or eliminating radiofrequency microneedle erythema, characterized in that, include: A multiphase radio frequency generator is configured to output M-phase radio frequency signals, where M=3, and each phase signal has the same frequency and amplitude. The phase difference of the M-phase signals output by the multiphase radio frequency generator is 360° / M. The microneedle electrode array includes multiple microneedles, which are divided into M phase groups. The microneedles in each phase group are electrically connected, and the phase group distribution of the multiple microneedles satisfies the following condition: in any local area composed of adjacent microneedles, there is at least one microneedle containing each phase group. The microneedles of the M phase groups of the microneedle electrode array are connected to the M phase output terminals of the multiphase radio frequency generator. When the multiphase radio frequency generator outputs the M-phase signal, a rotating electric field is excited in the subcutaneous tissue corresponding to the microneedle electrode array, avoiding the formation of an energy concentration area in the skin tissue that is consistent with the shape of the microneedle array, thereby reducing or eliminating the punctate erythema.

2. The multiphase radiofrequency ablation system according to claim 1, characterized in that, When multiple microneedles are arranged in a rectangular pattern, in any 3×3 local area formed by adjacent microneedles, each row and each column of the 3×3 area contains one microneedle of each of the three phases.

3. The multiphase radiofrequency ablation system according to claim 1, characterized in that, The multiphase RF generator includes a programmable logic control unit and a programmable multiphase phase modulation module. The programmable multiphase phase modulation module is configured to output a multiphase signal with the 360° / M phase difference according to the instructions of the programmable logic control unit.

4. The multiphase radiofrequency ablation system according to claim 3, characterized in that, The programmable multiphase phase modulation module is implemented using direct digital frequency synthesis technology and includes a phase accumulator and a phase control word register.

5. The multiphase radiofrequency ablation system according to claim 1, characterized in that, The radio frequency signal output by the multiphase radio frequency generator meets the following operating conditions: the duration of a single output is 20ms to 80ms, and the total output power is 5W to 40W.

6. The multiphase radiofrequency ablation system according to claim 5, characterized in that, The total output power is 12W, and the duration of a single output is 60ms.

7. The multiphase radiofrequency ablation system according to claim 1, characterized in that, The microneedle meets the following condition: the depth of the microneedle penetrating the skin is 0.5 mm to 3.0 mm.

8. The multiphase radiofrequency ablation system according to claim 7, characterized in that, The microneedles penetrate the skin to a depth of 1.5 mm.

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