A laser hair removal safety protection method and system based on skin color detection

Abstract

The application discloses a kind of laser hair removal safety protection method and system based on skin color detection, it is related to medical cosmetology technical field;Method includes: before laser emission, the optical reflection data and skin impedance data of target skin area are collected by multimodal sensor;Determine skin color grade according to optical reflection data, and determine skin water content according to skin impedance data;Determine maximum allowable laser energy density according to skin color grade and skin water content;Maximum allowable laser energy density is compared with current set laser energy density, if current set laser energy density exceeds maximum allowable laser energy density, then prohibit laser hair removal equipment to emit pulsed laser;In continuous multiple treatment, the skin temperature of target skin area is detected in real time, and when skin temperature rises and exceeds set value, subsequent pulse interval is extended and / or subsequent pulse energy is reduced.The application can limit laser energy and dynamically manage heat accumulation, to improve laser hair removal safety.

Description

Technical Field

[0001] This invention relates to the field of medical aesthetics technology, and in particular to a method and system for ensuring the safety of laser hair removal based on skin color detection. Background Technology

[0002] Laser hair removal is a widely used medical aesthetic technique. Its principle involves using a specific wavelength of laser light to penetrate the skin's surface, where it is selectively absorbed by the melanin in the hair follicles. This photothermal effect destroys the hair follicles, achieving long-lasting hair removal. With the continuous development of medical device technology, laser hair removal devices are becoming increasingly popular in both medical and home settings, and their treatment safety has become a key focus of the industry.

[0003] However, the degree of laser energy absorption is closely related to the melanin content in the skin, and skin color differences significantly affect treatment effectiveness and safety. During laser hair removal, darker skin absorbs laser energy much more readily than lighter skin. If a person with darker skin receives the same intensity of laser energy as someone with lighter skin, the excess energy will accumulate in the epidermis and convert into thermal damage, easily leading to burns, pigmentation, and other medical accidents. Therefore, it is necessary to strictly limit the laser energy density according to the user's skin color to ensure the safety of the treatment process.

[0004] Currently, traditional laser hair removal devices generally require users to manually select the appropriate skin tone level before treatment, and the device then determines the laser energy output based on the selected level. This method, which relies entirely on manual judgment and operation, has significant drawbacks: Firstly, ordinary users lack professional medical knowledge and find it difficult to accurately judge their own skin tone, making level selection prone to errors; secondly, users may intentionally select excessively high levels to achieve better hair removal results, leading to a high risk of misoperation, and the device itself cannot recognize the true skin tone and automatically intervene, posing a significant safety hazard. Furthermore, in continuous multi-treatment modes, the heat released by each laser pulse accumulates within the skin, and existing devices generally lack mechanisms for effectively monitoring and dynamically responding to changes in skin temperature. This lack of timely control over heat accumulation can easily cause skin burns. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a laser hair removal safety protection method and system based on skin color detection, which can automatically limit laser energy and dynamically manage heat accumulation, thereby improving the safety of laser hair removal.

[0006] To achieve the above objectives, this invention provides a laser hair removal safety protection method based on skin color detection, applied to laser hair removal equipment, comprising: Before laser emission, optical reflection data and skin impedance data of the target skin area are collected using a multimodal sensor; determining a skin color grade according to the optical reflection data, and determining a skin water content according to the skin impedance data; determining a maximum allowed laser energy density according to the skin color grade and the skin water content; comparing the maximum allowed laser energy density with a current set laser energy density, and if the current set laser energy density exceeds the maximum allowed laser energy density, prohibiting the laser hair removal device from emitting pulsed laser; in a continuous multi-shot treatment, detecting a skin temperature of a target skin area in real time, and when the skin temperature rises above a set value, extending a subsequent pulse interval and / or reducing a subsequent pulse energy.

[0007] Optionally, the multi-modal sensor comprises an optical reflection sensor for collecting optical reflection data and a skin impedance sensor for collecting skin impedance data.

[0008] Optionally, the multi-modal sensor further comprises an infrared distance measuring sensor for detecting a distance between a probe of the laser hair removal device and a target skin area; the method further comprises: when the distance is within a preset standard treatment distance threshold, starting the optical reflection sensor to collect optical reflection data, and starting the skin impedance sensor to collect skin impedance data; when the distance is greater than the preset standard treatment distance threshold, prohibiting the laser hair removal device from emitting pulsed laser.

[0009] Optionally, determining a maximum allowed laser energy density according to the skin color grade and the skin water content comprises: determining a basic maximum allowed laser energy density corresponding to the skin color grade according to a preset skin color grade and energy density correspondence relationship; determining an energy density correction coefficient according to the skin water content; correcting the basic maximum allowed laser energy density according to the energy density correction coefficient to obtain the maximum allowed laser energy density.

[0010] Optionally, determining a maximum allowed laser energy density according to the skin color grade and the skin water content comprises: looking up a maximum allowed laser energy density corresponding to the skin color grade and the skin water content together from a preset correspondence table.

[0011] Optionally, extending a subsequent pulse interval and / or reducing a subsequent pulse energy comprises: determining a cumulative thermal effect parameter according to a skin temperature detected in real time in a continuous multi-shot treatment; According to the cumulative thermal effect parameter, a subsequent pulse interval is prolonged and / or a subsequent pulse energy is reduced.

[0012] The application further provides a laser hair removal safety protection system based on skin color detection, applied to a laser hair removal device, comprising: A multi-modal detection unit is configured to collect optical reflection data and skin impedance data of a target skin area by a multi-modal sensor before laser emission; A skin quality parameter determination unit is configured to determine a skin color grade according to the optical reflection data and determine a skin water content according to the skin impedance data; A maximum allowed energy density determination unit is configured to determine a maximum allowed laser energy density according to the skin color grade and the skin water content; A light emission locking unit is configured to compare the maximum allowed laser energy density with a current set laser energy density, and if the current set laser energy density exceeds the maximum allowed laser energy density, the laser hair removal device is prohibited from emitting pulsed laser; A heat accumulation protection unit is configured to detect a skin temperature of the target skin area in real time in continuous multi-shot treatment, and when the skin temperature rises above a set value, a subsequent pulse interval is prolonged and / or a subsequent pulse energy is reduced.

[0013] According to the specific embodiments of the application, the following technical effects are achieved: The laser hair removal safety protection method based on skin color detection provided by the application collects optical reflection data and skin impedance data of a target skin area by a multi-modal sensor before laser emission, and determines a skin color grade and a skin water content accordingly, without the need for a user to manually select a skin color level, thereby reducing the security risks caused by artificial judgment deviation or misoperation.

[0014] Meanwhile, the maximum allowed laser energy density is determined according to the skin color grade and the skin water content, which can automatically limit deep skin color within a safe energy range, thereby avoiding medical accidents such as burns and pigmentation caused by deep skin color absorbing much more laser energy than light skin color. The maximum allowed laser energy density is compared with the current set laser energy density, and if the current set laser energy density exceeds the maximum allowed laser energy density, the laser hair removal device is prohibited from emitting pulsed laser, which can further prevent excessive energy output. In continuous multi-shot treatment, the skin temperature of the target skin area is detected in real time, and when the skin temperature rises above a set value, a subsequent pulse interval is prolonged and / or a subsequent pulse energy is reduced, which helps to control heat accumulation and reduce the risk of skin burns caused by continuous multi-shot treatment. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, exemplary embodiments of the application are shown.

[0016] Figure 1 A method flowchart of the skin color detection-based laser hair removal safety protection method shown in an embodiment of the present application is shown in Figure 1. Figure 2 A module structure diagram of the skin color detection-based laser hair removal safety protection system shown in an embodiment of the present application is shown in Figure 2. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0018] Please refer to Figure 1 , Figure 1 A method flowchart of the skin color detection-based laser hair removal safety protection method is shown in Figure 1.

[0019] The skin color detection-based laser hair removal safety protection method is applied to a laser hair removal device, and the method comprises the following steps. S101: Before laser emission, optical reflection data and skin impedance data of a target skin area are collected by a multi-modal sensor.

[0020] In the working process of the laser hair removal device, the target skin area needs to be detected before laser emission. Since deep skin color skin has much higher absorption of laser energy than light skin color, the traditional device requires the user to manually select the skin color level, which has high risk of misoperation and is easy to cause medical accidents such as burns and pigmentation. Therefore, the skin color level and skin water content of the target skin area need to be detected in real time within milliseconds before laser emission. These information can be collected by a multi-modal sensor, which includes an optical reflection sensor for collecting optical reflection data and a skin impedance sensor for collecting skin impedance data.

[0021] Multimodal sensors can be integrated into the handle of laser hair removal devices and combined with contact skin impedance sensors, ranging and reflection sensors to form a multimodal detection module. This multimodal detection module can form an integrated improved module that combines infrared ranging and positioning, impedance skin verification, NTC closed-loop ice-compression temperature control, pre-operative skin quality detection, and intra-operative dynamic protection, rather than being a purchased standardized product. The multimodal sensor may include a high-transmittance infrared silicone dustproof protective layer, an infrared dToF ranging sensor module, a light-shielding composite isolation rib, a ring-shaped metal impedance electrode contact layer, a semiconductor cooling TEC PAL patch, an NTC miniature temperature measuring resistor, an optical collimating lens, a beam splitter filter, a ring-shaped multi-band LED light source, and a metal optical path separator, etc. The main control PCB board may include an infrared ranging I 2 The system includes a C-sampling circuit, an impedance AC operational amplifier sampling circuit, an NTC-PID temperature control drive circuit, a TEC cooling H-bridge drive, and an embedded computing MCU. A high-transmittance infrared silicone dustproof protective layer is also compatible with ice-applied metal surface bonding. Light-shielding composite isolation ribs physically separate the infrared ranging optical path, the optical detection optical path, and the laser treatment optical path, preventing strong light crosstalk from causing ranging saturation failure. A metal optical path separator isolates the strong light from laser treatment, protecting the optical photosensitive chip. The infrared dToF ranging sensor module can include a 940nm VCSEL emitter and a SPAD single-photon receiver array.

[0022] Optical reflection data can be acquired by an optical reflection sensor. The optical reflection sensor may include a ring-shaped multi-band LED light source, an optical collimating lens, a beam-splitting filter, and an optical photosensitive chip. The ring-shaped multi-band LED light source emits detection light towards the target skin area. The optical collimating lens and beam-splitting filter collimate and split the detection light. The optical photosensitive chip receives the light reflected back from the target skin area, thus obtaining optical reflection data. This optical reflection data reflects the reflection characteristics of the target skin area to the detection light, providing a basis for determining skin tone level. Due to the light-shielding composite isolation ribs and the metal optical path separator, the optical detection optical path is isolated from the laser treatment optical path and the infrared ranging optical path, reducing strong light crosstalk and improving the accuracy of optical reflection data acquisition.

[0023] Skin impedance data can be acquired by a skin impedance sensor. The skin impedance sensor may include a ring-shaped metal impedance electrode contact layer. This layer contacts the target skin area, and an AC signal is applied to the target skin area via an impedance AC operational amplifier sampling circuit to acquire skin impedance data. This skin impedance data reflects the electrical characteristics of the target skin area, providing a basis for determining skin moisture content. Once infrared ranging is complete, the ring-shaped impedance electrode AC sampling can be initiated immediately to complete a secondary verification of the human skin medium. Through multimodal fusion of optical reflectance data and skin impedance data, more comprehensive skin texture information of the target skin area can be obtained before laser emission, avoiding potential errors associated with single detection methods.

[0024] The multimodal sensor completes data acquisition before laser emission, and the acquisition process can be performed within a millisecond-level detection window before laser emission. Because the multimodal sensor is integrated into the handle, it has a fast response speed and can work with the device's main control PCB board to complete real-time sampling, thus enabling the timely acquisition of optical reflection data and skin impedance data before light emission.

[0025] S102: Determine skin tone level based on optical reflectance data and skin moisture content based on skin impedance data.

[0026] Before laser emission, a multimodal sensor acquires optical reflectance and skin impedance data of the target skin area. The embedded MCU in the main control PCB board then processes this data in real time. The main control PCB board may include an impedance AC operational amplifier sampling circuit and an embedded MCU. The impedance AC operational amplifier sampling circuit samples the skin impedance data, while the embedded MCU processes the optical reflectance and skin impedance data, thereby determining the skin color grade and skin moisture content of the target skin area within milliseconds before laser emission.

[0027] For optical reflection data, the optical reflection sensor can include a ring-shaped multi-band LED light source, an optical collimating lens, a beam-splitting filter, and an optical photosensitive chip. The detection light emitted from the ring-shaped multi-band LED light source is collimated by the optical collimating lens and split by the beam-splitting filter before illuminating the target skin area. The light reflected from the target skin area is received by the optical photosensitive chip, forming optical reflection data. Different skin tones have different melanin contents, resulting in different absorption and reflection characteristics of the detection light. Darker skin absorbs laser energy much more than lighter skin, and its reflection characteristics of the detection light also differ from those of lighter skin. Therefore, the skin tone level corresponding to the target skin area can be determined by looking up a table or calculation based on the correspondence between the optical reflection data and a preset skin tone level. This process can be completed within a millisecond-level detection window before laser emission, achieving millisecond-level real-time skin tone detection and avoiding reliance on manual selection of skin tone levels by the user.

[0028] For skin impedance data, a skin impedance sensor may include a ring-shaped metal impedance electrode contact layer. This contact layer contacts the target skin area, and an AC signal is applied to the target skin area via an impedance AC operational amplifier sampling circuit to acquire skin impedance data. Skin impedance data reflects the electrical characteristics of the target skin area. Since skin moisture content affects the skin's conductivity, the skin moisture content of the target skin area can be determined by looking up a table or by calculation based on the skin impedance data and a preset correspondence between skin moisture content and electrical impedance data. Indirectly assessing moisture content through skin impedance can help determine the risk of burns.

[0029] Through the above processing, optical reflectance data and skin impedance data are fused in a multimodal manner, enabling the acquisition of more comprehensive skin texture information of the target skin area before laser emission, avoiding the errors that may exist in a single detection method. This method does not require users to manually select skin tone levels; instead, it determines the skin tone level and skin moisture content based on the actual detection data of the target skin area, providing a basis for subsequently determining the maximum permissible laser energy density.

[0030] S103: The maximum permissible laser energy density is determined based on skin tone grade and skin moisture content.

[0031] After obtaining the skin tone level and skin moisture content of the target skin area, the embedded MCU on the main control PCB board can determine the maximum permissible laser energy density for this treatment based on these two parameters. This maximum permissible laser energy density represents the upper limit of laser energy density that the laser hair removal device can safely output under the current skin conditions. The maximum permissible laser energy density is dynamically limited based on the detection results, automatically reducing it to a safe range for darker skin tones, thereby avoiding medical accidents such as burns and pigmentation caused by excessive laser energy absorption in darker skin.

[0032] In one embodiment, determining the maximum permissible laser energy density based on skin tone grade and skin moisture content includes: Based on the preset correspondence between skin tone level and energy density, determine the basic maximum allowable laser energy density corresponding to the skin tone level; The energy density correction factor is determined based on skin moisture content; The maximum permissible laser energy density is obtained by correcting the basic maximum permissible laser energy density based on the energy density correction factor.

[0033] Because the melanin content varies in target skin areas of different skin tones, the absorption of laser energy also differs significantly, with darker skin absorbing laser energy much more readily than lighter skin. Therefore, a pre-established correspondence between skin tone levels and a baseline maximum permissible laser energy density can be stored in the laser hair removal device's memory. This correspondence can exist in the form of a lookup table, curve, or calculation formula, and its specific values ​​can be pre-calibrated based on clinical or experimental data, ensuring that the baseline maximum permissible laser energy density for darker skin is lower than that for lighter skin. Based on the skin tone level of the target skin area, a baseline maximum permissible laser energy density can be determined from this correspondence. This baseline maximum permissible laser energy density represents the upper limit of laser energy density allowed for that skin tone level, without considering the influence of skin moisture content.

[0034] After obtaining the baseline maximum permissible laser energy density, it needs to be corrected for it based on skin moisture content. Skin moisture content affects the target skin area's tolerance to thermal damage; skin impedance indirectly assesses moisture content and can help determine the risk of burns. An energy density correction factor is determined based on skin moisture content, and this factor is used to adjust the baseline maximum permissible laser energy density. When skin moisture content is low, the target skin area's tolerance to thermal damage may decrease, and the energy density correction factor can appropriately reduce the maximum permissible laser energy density. When skin moisture content is within the normal range, the energy density correction factor can be determined based on a preset relationship. The energy density correction factor can be obtained from a table based on skin moisture content or calculated based on the preset relationship between skin moisture content and the correction factor. Through this correction, the maximum permissible laser energy density reflects not only skin color differences but also skin moisture content differences, thus more accurately matching the current target skin area's tolerance.

[0035] The final maximum permissible laser energy density can be obtained by correcting the base maximum permissible laser energy density using an energy density correction factor. The correction method can employ multiplication, weighting, or other preset calculations. For example, the correction relationship can be expressed as: Maximum permissible laser energy density = Base maximum permissible laser energy density × Energy density correction factor. This correction allows for further adjustment of the safety threshold based on skin moisture content, beyond the basic safety range determined by skin tone level, making the maximum permissible laser energy density more consistent with the actual condition of the target skin area. This automatically reduces the sensitivity of darker skin tones to a safe range, avoiding the risk of accidental operation from manual selection of skin tone levels and reducing the possibility of burns, pigmentation, and other medical accidents.

[0036] In another embodiment, determining the maximum permissible laser energy density based on skin color grade and skin moisture content includes: Find the maximum permissible laser energy density corresponding to both skin tone level and skin moisture content from the preset correspondence table.

[0037] In applications, a preset mapping table can be pre-stored in the laser hair removal device. This table uses skin tone level and skin moisture content as index variables and pre-sets the maximum allowable laser energy density for each combination of skin tone level and skin moisture content. This preset mapping table can be stored in the laser hair removal device's memory and accessed by the embedded MCU in the main control PCB board. The preset mapping table can be in a two-dimensional table format, for example, with skin tone level as the row and skin moisture content as the column, with each cell storing a maximum allowable laser energy density; other data structures that facilitate querying can also be used. The maximum allowable laser energy densities stored in the table represent the upper limit of laser energy density that the laser hair removal device can safely output under the corresponding skin tone level and skin moisture content conditions. The values ​​in the preset correspondence table can be pre-calibrated based on clinical or experimental data, ensuring that the maximum permissible laser energy density for dark skin is lower than that for light skin. Under the same skin tone level, the maximum permissible laser energy density corresponding to low skin moisture content can be appropriately lower than that corresponding to normal skin moisture content, thus more comprehensively reflecting the tolerance of the target skin area to thermal damage.

[0038] Since the lookup process does not require complex real-time calculations, it only needs to read the pre-stored values ​​based on the determined skin color level and skin moisture content. Therefore, the response speed is fast, which can meet the real-time safety judgment requirements within the millisecond-level detection window before laser emission. It is also suitable for implementation in the narrow space and with limited computing resources at the handle end of the laser hair removal device.

[0039] S104: Compare the maximum permissible laser energy density with the currently set laser energy density. If the currently set laser energy density exceeds the maximum permissible laser energy density, then prohibit the laser hair removal device from emitting pulsed laser.

[0040] After determining the maximum permissible laser energy density for the target skin area, the laser hair removal device can compare it with the currently set laser energy density before laser emission. The currently set laser energy density can be the energy density set by the user through the laser hair removal device, or it can be the energy density automatically selected by the device based on the treatment mode. This comparison process can be executed by the embedded computing MCU in the main control PCB board, and the comparison result is used to control the laser hair removal device's light emission permissions. This comparison can be completed within a millisecond-level detection window before laser emission, thus allowing for timely safety judgments before light emission.

[0041] If the currently set laser energy density does not exceed the maximum permissible laser energy density, it indicates that the current treatment parameters are within the safe range that the target skin area can tolerate, and the laser hair removal device can emit pulsed laser according to the currently set laser energy density. If the currently set laser energy density exceeds the maximum permissible laser energy density, it indicates that the current treatment parameters pose a risk of medical accidents such as burns or pigmentation. In this case, the laser hair removal device will automatically trigger a lockout, prohibiting the emission of pulsed laser. Prohibiting the emission of pulsed laser can be achieved through hardware interruption or software control, such as cutting off the laser trigger signal, locking laser trigger permissions, or directly prohibiting light emission. Because this comparison and lockout are completed before laser emission, unsafe laser output can be blocked in time before light emission.

[0042] Through the above methods, the device can dynamically limit the maximum permissible laser energy density based on the detection results. Darker skin tones are automatically reduced to a safe range, and if the energy density exceeds the safety threshold, the device automatically locks off the trigger, preventing light emission and avoiding the risk of misoperation caused by users manually selecting skin tone levels. Even if users lack professional medical knowledge or intentionally select excessively high levels in pursuit of hair removal effects, the device can identify the actual skin condition before laser emission and automatically intervene, preventing pulsed laser emission exceeding the safety threshold, thereby reducing the possibility of medical accidents such as burns and pigmentation.

[0043] S105: During continuous multi-shot treatment, the skin temperature of the target skin area is detected in real time, and when the skin temperature rises above the set value, the interval between subsequent pulses is extended and / or the energy of subsequent pulses is reduced.

[0044] In continuous multi-pulse treatments, laser hair removal devices may emit multiple laser pulses in succession, and the heat released by each laser pulse will continuously accumulate in the target skin area. Without a mechanism for effectively monitoring and dynamically responding to changes in skin temperature, this heat accumulation cannot be controlled in time, easily causing skin burns. Therefore, during continuous multi-pulse treatments, it is necessary to monitor the skin temperature of the target area in real time so that subsequent pulse outputs can be adjusted promptly based on changes in skin temperature, achieving dynamic management of heat accumulation and ensuring safety in multi-pulse scenarios.

[0045] Skin temperature can be detected using an NTC miniature thermocouple. This NTC miniature thermocouple fits snugly against the cooling metal end of the laser hair removal device, simultaneously collecting skin contact temperature. The detected temperature signal is transmitted to the main control PCB board, where it is received and processed by the embedded MCU. The main control PCB board can include an NTC-PID temperature control drive circuit and a TEC cooling H-bridge drive. The cold end of the semiconductor cooling TEC PAL patch connects to the cooling metal head, while the hot end connects to the internal heat dissipation copper foil of the handle, thus forming an NTC closed-loop cooling temperature control system in conjunction with the NTC-PID temperature control drive circuit and the TEC cooling H-bridge drive. This closed-loop cooling temperature control can be synchronized with the laser treatment process, providing cooling buffering and temperature regulation to the target skin area during treatment.

[0046] When the detected skin temperature exceeds a set value, the laser hair removal device can automatically extend the interval between subsequent pulses and / or reduce the energy of subsequent pulses. Extending the interval allows more time for the target skin area to dissipate heat, while reducing the energy of subsequent pulses reduces the heat generated per pulse. Both methods can be used individually or in combination. This reduces the amount of heat injected into the target skin area per unit time, preventing heat accumulation and burns. The set value can be preset based on clinical or experimental data to ensure both hair removal effectiveness and safety. This adjustment process can be continuous and dynamically executed based on real-time detected skin temperature until the skin temperature returns to a safe range.

[0047] Through the above-mentioned dynamic management of heat accumulation, the interval and / or energy of subsequent pulses can be dynamically adjusted according to changes in skin temperature during continuous multi-treatment, avoiding skin burns caused by heat accumulation and improving the safety of the laser hair removal treatment process.

[0048] Specifically, the aforementioned extension of the subsequent pulse interval and / or reduction of the subsequent pulse energy includes: The cumulative thermal effect parameters were determined based on the skin temperature monitored in real time during continuous multiple treatments. Based on the cumulative thermal effect parameters, extend the interval between subsequent pulses and / or reduce the energy of subsequent pulses.

[0049] During continuous multi-pulse treatment, the skin temperature of the target skin area can be monitored in real time, and the cumulative thermal effect parameter can be determined accordingly. The cumulative thermal effect parameter characterizes the degree of heat accumulation caused by multiple consecutive pulses on the target skin area. The larger the cumulative thermal effect parameter, the more severe the heat accumulation in the target skin area, and the higher the risk of heat accumulation burns.

[0050] When determining the cumulative thermal effect parameter, the skin temperature detected each time can be compared with the initial temperature to obtain the temperature rise rate; alternatively, the skin temperature detected each time can be compared with the previously detected skin temperature to obtain the temperature rise rate; or the degree of heat accumulation can be calculated by combining at least one of the following: the number of pulses emitted, the energy of the emitted pulses, the pulse interval, and the trend of skin temperature change. For example, after each pulse is emitted, the cumulative thermal effect parameter can be updated based on the change in skin temperature; or the cumulative thermal effect parameter can be obtained by integrating, weighting, or performing other preset calculations on the skin temperatures detected over a period of time. The specific calculation method can be set according to actual needs, as long as it can characterize the degree of skin heat accumulation during continuous multiple treatments.

[0051] After obtaining the cumulative thermal effect parameters, the interval between subsequent pulses can be extended and / or the energy of subsequent pulses can be reduced based on these parameters. One or more thresholds related to the cumulative thermal effect parameters can be preset. When the cumulative thermal effect parameters reach or exceed the preset thresholds, the laser hair removal device automatically extends the interval between subsequent pulses, allowing more time for the target skin area to dissipate heat; and / or reduces the energy of subsequent pulses, reducing the heat generated per pulse. Extending the interval between subsequent pulses and reducing the energy of subsequent pulses can be performed individually or in combination. The adjustment range can be determined based on the magnitude of the cumulative thermal effect parameters. For example, the larger the cumulative thermal effect parameters, the greater the extension of the interval between subsequent pulses, and / or the greater the reduction in the energy of subsequent pulses. A pre-established correspondence between the cumulative thermal effect parameters and the extension and / or reduction of the pulse interval can be obtained by looking up a table or calculation. When the cumulative thermal effect parameters exceed different preset levels, the interval between subsequent pulses can be gradually extended according to a preset gradient, or the energy of subsequent pulses can be gradually reduced according to a preset gradient, or the interval can be extended and the energy reduced simultaneously.

[0052] The above method enables the determination of cumulative thermal effect parameters based on real-time monitored skin temperature during continuous multi-treatment sessions. This allows for dynamic adjustment of subsequent pulse intervals and / or pulse energy, achieving dynamic management of heat accumulation. This ensures safety in multi-pulse scenarios, preventing skin burns caused by heat accumulation and improving the safety of the laser hair removal treatment process. After adjustment, the skin temperature of the target area can continue to be monitored in real-time, and the cumulative thermal effect parameters can be determined again, thus forming temperature feedback regulation and further improving the safety and reliability of the laser hair removal process.

[0053] In one embodiment, the multimodal sensor further includes an infrared ranging sensor for detecting the distance between the probe of the laser hair removal device and the target skin area; the method further includes: When the distance is within the preset standard treatment distance threshold, the optical reflection sensor is activated to collect optical reflection data, and the skin impedance sensor is activated to collect skin impedance data. When the distance exceeds the preset standard treatment distance threshold, the laser hair removal device is prohibited from emitting pulsed laser.

[0054] In applications, the infrared ranging sensor can be a miniature dToF infrared ranging chip, such as the VL53L0X or MT3801, which has a built-in 940nm invisible infrared VCSEL light source. It directly calculates the straight-line distance between the probe and the skin through photon time of flight, with an effective range of 0~20mm, ranging accuracy of ±0.1mm, and a maximum sampling frame rate of 50Hz. Compared with ultrasonic ranging, infrared ranging does not generate weak analog signals due to acoustic vibration interference, is smaller in size, has a faster response speed, and is free from ranging errors caused by air temperature and humidity, making it suitable for use in small probe spaces on handles.

[0055] During standby, the infrared ranging module can continuously sample at a low power consumption with a 50ms cycle, outputting the distance between the probe and the object in front in real time. The preset standard treatment distance threshold can be 2mm~4mm. Layered judgment is performed based on the ranging value. When the ranging value ∈ [2,4]mm, the embedded computing MCU in the main control PCB board can determine that the handle has reached the standard working position, wake up the entire multimodal detection and cooling function through hardware interrupt, start the optical reflection sensor to collect optical reflection data of the target skin area, and start the skin impedance sensor to collect skin impedance data of the target skin area. After the infrared ranging is in place, the annular metal impedance electrode contact layer can be immediately activated to perform AC sampling and complete the secondary verification of the human skin medium.

[0056] When the distance measured is greater than 4mm, it indicates that the probe is far from the skin, and the semiconductor cooling module can be completely powered off and put into sleep mode. The laser triggering permission is permanently locked, preventing the laser hair removal device from emitting pulsed lasers. Optionally, when the distance measured is less than 2mm, it indicates that the probe is excessively pressing on the skin. A pressure warning can be marked, and the cooling power will be automatically increased by 15% to enhance the ice pack buffer.

[0057] By using the above method, it can be determined whether the probe is in the standard treatment position before the laser is emitted. Only when the distance is within the preset standard treatment distance threshold will the acquisition of optical reflection data and skin impedance data be initiated. Otherwise, the light emission will be prohibited, thereby avoiding accidental laser triggering when the probe is far away from the skin and improving the safety and reliability of the laser hair removal device.

[0058] Corresponding to the aforementioned application function implementation method embodiments, the present invention also provides a laser hair removal safety protection system based on skin color detection and corresponding embodiments.

[0059] Please see Figure 2 , Figure 2This is a schematic diagram of the module structure of a laser hair removal safety protection system based on skin color detection.

[0060] A skin color detection-based safety protection system for laser hair removal, applied to laser hair removal equipment, includes: The multimodal detection unit 21 is used to collect optical reflection data and skin impedance data of the target skin area through a multimodal sensor before laser emission; The skin texture parameter determination unit 22 is used to determine the skin color level based on optical reflection data and to determine the skin moisture content based on skin impedance data. The maximum permissible energy density determination unit 23 is used to determine the maximum permissible laser energy density based on skin color grade and skin moisture content; The light emission interlocking unit 24 is used to compare the maximum allowable laser energy density with the currently set laser energy density. If the currently set laser energy density exceeds the maximum allowable laser energy density, the laser hair removal device is prohibited from emitting pulsed laser. The heat accumulation protection unit 25 is used to detect the skin temperature of the target skin area in real time during continuous multi-treatment, and to extend the subsequent pulse interval and / or reduce the energy of the subsequent pulse when the skin temperature rises above a set value.

[0061] Regarding the system in the above embodiments, the specific manner in which each unit module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated further here.

[0062] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A safety protection method for laser hair removal based on skin color detection, characterized in that, Applications in laser hair removal equipment include: Before laser emission, optical reflection data and skin impedance data of the target skin area are collected using a multimodal sensor; Skin color grade is determined based on the optical reflectance data, and skin moisture content is determined based on the skin impedance data; The maximum permissible laser energy density is determined based on the skin color grade and the skin moisture content. The maximum permissible laser energy density is compared with the currently set laser energy density. If the currently set laser energy density exceeds the maximum permissible laser energy density, the laser hair removal device is prohibited from emitting pulsed laser. During continuous multi-shot treatment, the skin temperature of the target skin area is monitored in real time, and when the skin temperature rises above the set value, the interval between subsequent pulses is extended and / or the energy of subsequent pulses is reduced.

2. The method according to claim 1, characterized in that, The multimodal sensor includes an optical reflection sensor for acquiring optical reflection data and a skin impedance sensor for acquiring skin impedance data.

3. The method according to claim 2, characterized in that, The multimodal sensor further includes an infrared ranging sensor, which is used to detect the distance between the probe of the laser hair removal device and the target skin area; the method further includes: When the distance is within a preset standard treatment distance threshold, the optical reflection sensor is activated to collect optical reflection data, and the skin impedance sensor is activated to collect skin impedance data. When the distance exceeds a preset standard treatment distance threshold, the laser hair removal device is prohibited from emitting pulsed laser.

4. The method according to claim 1, characterized in that, Determining the maximum permissible laser energy density based on the skin color grade and the skin moisture content includes: Based on the preset correspondence between skin color level and energy density, determine the basic maximum allowable laser energy density corresponding to the skin color level; The energy density correction factor is determined based on the skin moisture content. The maximum permissible laser energy density is obtained by correcting the basic maximum permissible laser energy density according to the energy density correction coefficient.

5. The method according to claim 1, characterized in that, Determining the maximum permissible laser energy density based on the skin color grade and the skin moisture content includes: Find the maximum permissible laser energy density that corresponds to both the skin tone level and the skin moisture content from the preset correspondence table.

6. The method according to claim 1, characterized in that, Extending the interval between subsequent pulses and / or reducing the energy of subsequent pulses, including: The cumulative thermal effect parameters were determined based on the skin temperature monitored in real time during continuous multiple treatments. Based on the cumulative thermal effect parameters, the interval between subsequent pulses is extended and / or the energy of subsequent pulses is reduced.

7. A laser hair removal safety protection system based on skin color detection, characterized in that, Applications in laser hair removal equipment include: The multimodal detection unit is used to collect optical reflection data and skin impedance data of the target skin area through multimodal sensors before laser emission; A skin texture parameter determination unit is used to determine skin color level based on the optical reflection data and to determine skin moisture content based on the skin impedance data; A maximum permissible energy density determination unit is used to determine the maximum permissible laser energy density based on the skin color grade and the skin moisture content; The laser emission interlocking unit is used to compare the maximum allowable laser energy density with the currently set laser energy density. If the currently set laser energy density exceeds the maximum allowable laser energy density, the laser hair removal device is prohibited from emitting pulsed laser. The heat accumulation protection unit is used to detect the skin temperature of the target skin area in real time during continuous multi-treatment, and when the skin temperature rises above a set value, it extends the interval between subsequent pulses and / or reduces the energy of subsequent pulses.

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