Determine the moisture level or lipid level of the skin

Abstract

A system (100) and method for determining skin moisture level or lipid level is provided. The system (100) includes at least two electrodes (108) adapted to contact the skin and a signal generator (106) configured to generate an electrical signal at a frequency across the at least two electrodes (108). The system (100) is configured to measure a dielectric constant between the at least two electrodes (108). The system (100) is further configured to determine the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal.

Description

Technical Field

[0001] The present invention relates to systems and methods for determining the moisture level or lipid level of the skin. Background Art

[0002] Skin surface lipid (e.g., sebum) levels and water (e.g., hydration) levels are considered important factors in determining skin appearance and skin health. The correct balance between these components is an indicator of healthy skin and plays a central role in protecting and maintaining skin integrity. The hydration and lipid retention capacity of the skin is primarily related to the stratum corneum (SC). The SC acts as a barrier to water loss and is composed of a bilayer matrix of corneocytes and intercellular lipids. The water retention properties of the SC depend on (i) the presence of natural hygroscopic agents collectively referred to as natural moisturizing factors (NMFs) and (ii) the SC intercellular lipids that are orderly arranged to form a barrier to prevent transepidermal water loss.

[0003] Typically, when the skin contains 10%-20% moisture, the skin remains flexible, but becomes fragile when it drops below 10%. Skin lipids (e.g., sebum) are a mixture of fatty acids, triglycerides, proteins, and other molecules produced by sebaceous glands in the dermis. Skin lipids keep the skin smooth and flexible by sealing and retaining moisture in the corneal layer and preventing evaporation and bacterial infection. The sebum excretion rate (SER) reflects that the amount of lipid (e.g., sebum) produced is closely related to the physiological activity of the sebaceous glands. This is important information for the pathological occurrence of sebaceous gland disorders and rashes and acne.

[0004] An optimal balance between lipids and water content provides the skin with a radiant, smooth texture and the appearance of natural pigmentation, which is important from a cosmetic standpoint. Excessive lipid production can cause pore clogging, potentially leading to blemishes. Adequate amounts of skin hydration and lipids make the skin appear smooth, soft and supple, while a lack of moisture can cause the skin to appear dull and cracked, appearing older. Reduced efficiency of the skin's barrier and moisturizing functions results in easily dry, rough skin, which may be more susceptible to the risk of infection. Summary of the invention

[0005] As described above, moisture and lipid content are important factors in determining overall skin health, and there are hydration measurement devices that measure, for example, the capacitance or current conductivity of the skin and detect moisture on the skin based on these measurements. However, the inventors have observed that these measurements can actually depend on the level of skin moisture (e.g., hydration) and the level of lipids (e.g., oil), which can cause such devices to be inaccurate. For example, even if two identical pieces of hydrated skin are measured, the hydration level measured using such devices can change depending on the surface lipid level of the skin. Therefore, it is desirable to provide systems and methods for determining the moisture or lipid content level of the skin.

[0006] According to a first aspect, a system for determining the moisture level or lipid level of the skin is provided. The system comprises at least two electrodes adapted to contact the skin and a signal generator configured to generate an electrical signal at a frequency across the at least two electrodes. The system is configured to measure a dielectric constant between the at least two electrodes and to determine the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal.

[0007] In some embodiments, the signal generator can be configured to generate the electrical signal at a first frequency within the first frequency range. In these embodiments, the system can be configured to determine the moisture level of the skin based on the dielectric constant measured when the frequency of the signal is the first frequency.

[0008] In some embodiments, the first frequency range may be a frequency range from 10 Hz to 1000 Hz. In some embodiments, the first frequency range may be a frequency range from 10 Hz to 50 Hz. In some embodiments, the first frequency range may be a frequency range from 150 Hz to 750 Hz.

[0009] In some embodiments, the signal generator can be configured to generate an electrical signal at a second frequency in a second frequency range. In these embodiments, the system can be configured to determine the lipid level of the skin based on the dielectric constant measured when the frequency of the signal is the second frequency.

[0010] In some embodiments, the second frequency range may be different from the first frequency range.

[0011] In some embodiments, the second frequency range may be a frequency range from 1 kHz to 50 kHz. In some embodiments, the second frequency range may be a frequency range from 1 MHz to 100 MHz.

[0012] In some embodiments, the system can be configured to measure the dielectric constant at multiple frequencies to obtain multiple dielectric constant measurements.

[0013] In some embodiments, the system can be configured to determine the moisture level or lipid level of the skin by determining an average moisture level or lipid level of the skin from a plurality of dielectric constant measurements.

[0014] In some embodiments, the system can also be configured to compare the measured dielectric constant to one or more predefined curves that describe how the dielectric constant of the skin changes with frequency, and determine the moisture level or lipid level of the skin based on the comparison of the measured dielectric constant and the frequency of the radio frequency signal.

[0015] In some embodiments, the system may also be configured to determine skin condition based on the determined moisture level or lipid level.

[0016] In some embodiments, the system may also be configured to determine a recommendation for skin treatment based on the determined skin condition.

[0017] According to a second aspect, a method of operating a system to determine the moisture level or lipid level of the skin is provided. The system includes at least two electrodes adapted to contact the skin and a signal generator configured to generate an electrical signal at a frequency across the at least two electrodes. The method includes measuring a dielectric constant between the at least two electrodes, and determining the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal.

[0018] According to a third aspect, there is provided a computer program product comprising a non-transitory computer-readable medium having a computer-readable code embodied in the computer-readable medium, the computer-readable code being configured to, when executed by a suitable computer or processor, cause the computer or processor to perform the method as described above.

[0019] According to the aspects and embodiments described above, by considering the frequency of the electrical signal in determining the moisture level or lipid level from the measured dielectric constant, it is possible to substantially exclude the moisture level of the skin and independently measure the lipid level of the skin and / or substantially exclude the lipid level of the skin and independently measure the moisture level of the skin. More specifically, by determining the moisture level or lipid level based on the measured dielectric constant and the frequency of the electrical signal, the dielectric constant measurement can be performed at a more sensitive frequency for the property being measured (e.g., moisture level or lipid level). In this way, a more accurate measurement of the moisture level or lipid level of the skin can be determined. In addition, a single system (e.g., a single device) can be used to determine the moisture and lipid levels of the skin. The system and corresponding method can be used to achieve an assessment of the balance between the moisture level and the lipid level related to skin health, and therefore can be used to select suitable skin care treatments and products. The system and method can also be used to monitor the progress of such treatment.

[0020] These and other aspects will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments will now be described, by way of example only, with reference to the following drawings, in which:

[0022] Figure 1 is a diagram of a system according to an embodiment of the present invention;

[0023] Figure 2shows a graph of frequency versus skin dielectric constant for different skin types;

[0024] Figure 3 shows the ratio of dielectric constants comparing the dielectric constants of different skin types with respect to frequency;

[0025] Figure 4 A table showing example frequency ranges for determining lipid and water content of skin according to some embodiments;

[0026] Figure 5 shows the relative lipid and water content of different skin types according to one embodiment;

[0027] Figure 6 shows the relative lipid and water content of various skin conditions according to one embodiment; and

[0028] Figure 7 is a flow chart of an example of a method of operating a system for determining moisture level or lipid level of skin according to an embodiment. DETAILED DESCRIPTION

[0029] As described above, systems and methods are provided for determining the moisture (or hydration) or lipid (or sebum or oil) content level of skin.

[0030] Figure 1 A system 100 for determining the moisture level or lipid level of the skin is shown. The system includes at least two (e.g., at least one pair) electrodes 108 suitable for contacting the skin and a signal generator 106, which is configured to generate an electrical signal at a frequency across the at least two electrodes 108. In some embodiments, the system 100 described herein can be an apparatus. In short, the system 100 is configured to measure the dielectric constant between the at least two electrodes 108, and determine the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal. In use, the at least two electrodes and the skin form an electrical circuit. The electrical signal generated between the at least two electrodes 108 therefore passes through the skin between the at least two electrodes 108, so that the dielectric constant of the skin can be measured.

[0031] In some embodiments, at least two electrodes 108 may include at least one active electrode configured to transmit an electrical signal, and at least one corresponding return electrode configured to receive an electrical signal transmitted from at least one active electrode. In some embodiments, the at least two electrodes 108 may include at least two microelectrodes. An electrode in the at least two electrodes 108 may be located at any suitable distance from another electrode in the at least two electrodes 108. For example, in some embodiments, the electrodes may be located at a distance in the range of 0.1 mm to 1 mm from each other. In this way, the sensitivity of the system 100 may be increased, such as measuring the surface layer of the skin.

[0032] As described above, the inventors have observed that dielectric constant measurements of the skin can depend on both moisture and lipid levels, which can lead to inaccuracies in measurements of hydration levels obtained with existing equipment. By determining moisture level or lipid level based on the measured dielectric constant and the frequency of the electrical signal, dielectric constant measurements can be made at frequencies that are more sensitive to the property being measured (e.g., moisture level or lipid level). In this way, a more accurate measurement of the moisture or lipid content of the skin can be determined.

[0033] Those skilled in the art will be familiar with electrodes suitable for contacting the skin. In some embodiments, the pad (or sheet) may include at least two electrodes 108, and the pad may be suitable for contacting the skin. For example, each electrode may be partially embedded in the pad. In some embodiments, the at least two electrodes 108 (or a pad including the at least two electrodes 108) may include an adhesive surface that enables the at least two electrodes 108 (or a pad including the at least two electrodes 108) to adhere to the skin. In some embodiments, the at least two electrodes 108 may include an electrode array. In some embodiments, the at least two electrodes 108 (or electrode array) may be configured (or arranged) to cover an area of ​​interest on the skin. For example, an electrode array may be used to measure the dielectric constant of a larger area of ​​the skin for large-area mapping of skin conditions. In some embodiments, the electrode array may be included in, for example, a fingerprint sensor.

[0034] As previously described, the signal generator 106 of the system 100 is configured to generate an electrical signal at a frequency at at least two electrodes 108. In some embodiments, the signal generator 106 can be configured to generate a frequency pulse. The frequency pulse can be, for example, a fixed frequency pulse or a variable frequency pulse. In some embodiments, the pulse can include a low voltage pulse. In some embodiments, the signal generator 106 can be configured to generate a radio frequency (RF) signal. Therefore, in some embodiments where the signal generator 106 is configured to generate a frequency pulse, the pulse can include a radio frequency pulse.

[0035] As in Figure 1 As shown in FIG. 1 , in some embodiments, the system 100 may further include an amplifier 110 (such as a radio frequency amplifier). In some embodiments, the amplifier 110 may amplify the voltage output by the signal generator 106. Figure 1 As shown in FIG. 1 , in some embodiments, the system 100 may also include a dielectric constant measurement system (such as an impedance measurement system) 112. The dielectric constant measurement system 112 may, for example, measure the voltage across the at least two electrodes 108. When the at least two electrodes 108 are in contact with the skin (e.g., when the system is in use), the dielectric constant measurement system 112 may measure the current flowing through the circuit formed by the at least two electrodes 108 of the system 100 and the skin. The dielectric constant measurement system 112 may be configured to measure the dielectric constant between the electrodes by the measured current. Those skilled in the art will appreciate the manner in which the dielectric constant can be derived from the measured current.

[0036] In some embodiments, the system 100 can be mechanically implemented, for example, the dielectric constant measured between the electrodes can be displayed on an analog display. Such an analog display can be calibrated (for example, the scale can be shifted or scaled) so that the analog display shows the moisture level or lipid level.

[0037] In other embodiments, such as in Figure 1 As shown in , the system 100 may also include a processor 102. The processor 102 may, for example, be configured to control the signal generator 106 to generate an electrical signal at a frequency across at least two electrodes 108. For example, the processor 102 may be adapted to control the signal generator 106 to generate pulses of a desired frequency, voltage, and / or pulse duration. In some embodiments, a dielectric constant measurement system 112 may be controlled by the processor 102. Alternatively or additionally, in some embodiments, the output of the dielectric constant measurement system 112 may be sent to the processor 102 for subsequent processing and / or output (e.g., display to a user).

[0038] In general, in embodiments where the system 100 includes a processor 102, the processor 102 may control the operation of the system 100 to implement the methods described herein. The processor 102 may be implemented in a variety of ways using software and / or hardware to perform the various functions described herein. In a particular embodiment, the processor 102 may include a plurality of software and / or hardware modules, each of which is configured to perform or be used to perform a single or multiple steps of the methods described herein. The processor 102 may include one or more processors (such as one or more microprocessors, one or more multi-core processors, and / or one or more digital signal processors (DSPs)), one or more processing units and / or modules, and / or one or more controllers (such as one or more microcontrollers), which may be configured or programmed (e.g., using software or computer program code) to control or operate the system 100 in the manner described herein.

[0039] In some embodiments, for example, the processor 102 may include multiple (e.g., interoperable) processors, processing units and / or modules, multi-core processors and / or controllers configured for distributed processing. Those skilled in the art will appreciate that such processors, processing units and / or modules, multi-core processors and / or controllers may be located in different locations and may perform different steps and / or different parts of the individual steps of the methods described herein. The processor 102 may be implemented as a combination of dedicated hardware (amplifiers, preamplifiers, analog-to-digital converters (ADCs) and / or digital-to-analog converters (DACs)) to perform some functions and processors (e.g., one or more programmed microprocessors, controllers, DSPs and associated circuits) to perform other functions.

[0040] As in Figure 1 As shown in, in some embodiments, system 100 may include memory 104. Memory 104 may include instruction data representing an instruction set. For example, memory 104 may be configured to store instruction data in the form of program code, which program code may be executed by processor 102 so that system 100 operates in the manner described herein. In some embodiments, instruction data may include multiple software and / or hardware modules that are each configured to perform or are used to perform a single or multiple steps of the method described herein. In some embodiments, memory 104 may be part of a device that also includes one or more other components of system 100 (e.g., processor 102 and / or one or more other components of system 100). In an alternative embodiment, memory 104 may be part of a device that is separated from other components of system 100.

[0041] In some embodiments, the memory 104 may include multiple sub-memories, each of which is capable of storing an instruction data. In some embodiments in which the memory 104 includes multiple sub-memories, the instruction data representing the instruction set may be stored at a single sub-memories. In other embodiments in which the memory 104 includes multiple sub-memories, the instruction data representing the instruction set may be stored in multiple sub-memories. For example, at least one sub-memories may store instruction data representing at least one instruction in the instruction set, and at least one other sub-memories may store instruction data representing at least one other instruction in the instruction set. Therefore, according to some embodiments, instruction data representing different instructions may be stored at one or more different locations in the system 100. In some embodiments, the memory 104 may be used to store information, data, signals (e.g., dielectric constant signals) and measurements (e.g., dielectric constant measurements), which are acquired or manufactured by the system 100 (such as a processor of the system 100 or any other component of the system 100).

[0042] The memory may include any type of non-transitory machine-readable media such as cache or system memory including volatile and non-volatile computer memory such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), and electrically erasable PROM (EEPROM).

[0043] The processor 102 of the system 100 may be configured to communicate with the memory 104 to execute the set of instructions. The set of instructions, when executed by the processor 102, may cause the processor 102 to perform the methods described herein.

[0044] Return to Figure 1 In some embodiments, system 100 may include at least one user interface 114. In some embodiments, user interface 114 may be part of a device that also includes one or more other components of system 100 (e.g., processor 102, memory 104, and / or one or more other components of system 100). In alternative embodiments, user interface 114 may be part of a device that is separate from the other components of system 100.

[0045] The user interface 114 can be used to provide information generated by the method according to the embodiments of the present invention to a user of the system 100 (e.g., a medical professional, a dermatologist, a user in a home setting, or any other user of the system 100). When executed by the processor 102, the instruction set can cause the processor 102 to control one or more user interfaces 114 to provide information generated by the method according to the embodiments of the present invention. For example, according to some embodiments, the user interface 114 can be configured to present (e.g., provide, output or display) the moisture level or lipid level of the skin determined by the system 100. Alternatively or additionally, the user interface 114 can be configured to receive user input. In other words, the user interface 114 can allow the user of the system 100 to manually input instructions, data or information. The instruction set, when executed by the processor 102, can cause the processor 102 to obtain user input from one or more user interfaces 114.

[0046] The user interface 114 may be any user interface that enables information, data, or signals to be presented (or output or displayed) to a user of the system 100. Alternatively or additionally, the user interface 114 may be any user interface that enables a user of the system 100 to provide user input, interact with the system 100, and / or control the system 100. For example, the user interface 114 may include one or more switches, one or more buttons, a keypad, a keyboard, a mouse, a mouse wheel, a touch screen or application (e.g., on a tablet or smart phone), a display screen, a graphical user interface (GUI) or other visual presentation component, one or more speakers, one or more microphones or any other audio component, a component for providing tactile feedback (e.g., a vibration function), or any other user interface, or a combination of user interfaces.

[0047] It should be understood that Figure 1 Only components necessary to illustrate this aspect of the invention are shown, and in an embodiment of actual use, the system 100 may include components in addition to those shown. For example, the system 100 may include a battery or other power source for powering the system 100 or a device for connecting the system 100 to a main power source. The system 100 may also include a communication interface (or circuit system) for enabling the system 100 (or a component of the system 100) to communicate with a component, interface, memory, and / or device that is part of the system 100, or to communicate with a component, interface, memory, and / or device that is external to the system 100 (i.e., separate from the system 100 or remote from the system 100). This communication interface may communicate wirelessly with any component, interface, memory, and device via a wired connection or via any other communication (or data transfer) mechanism. In some wireless embodiments, the communication interface may communicate, for example, using radio frequency (RF), Bluetooth, or any other wireless communication technology.

[0048] As briefly described above, the system 100 is configured to measure the dielectric constant between at least two electrodes 112 and determine the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal.

[0049] In some embodiments, the signal generator 106 can be configured to generate an electrical signal at a first frequency and to generate an electrical signal at a second frequency, and the system 100 can be configured to measure moisture level when the generated electrical signal is at the first frequency and to measure lipid level when the generated electrical signal is at the second frequency.

[0050] Thus, the value of the frequency used to make the determination may depend on whether the system is to determine moisture level or lipid level.As mentioned above, the inventors have experimentally observed that the dielectric constant of skin depends on both the lipid content and the water content of the skin.

[0051] Figure 2 Graphs of dielectric constant versus (or relative to or as) frequency for breast tissue 202 (e.g., high lipid tissue), wet skin 204, and dry skin 206 are shown, respectively. Figure 2 Various ratios of dielectric constants can be determined that can be used to determine frequency ranges (eg, frequency bands) that are most sensitive to (and therefore best suited for measuring) water and lipid levels with improved sensitivity.

[0052] Figure 3 The ratio of dielectric constants at different frequencies is shown. The ratio of dielectric constant to lipid level for wet skin is shown by line 302, the ratio of wet skin to dry skin is shown by line 304, and the ratio of dry skin to lipid level is shown by line 306. Five frequency ranges f1 to f5 can then be defined, each frequency range being more sensitive to moisture level or more sensitive to lipid level (e.g., dielectric constant measurements made within the range are more heavily dependent on moisture level or on lipid level). In other words, within these ranges, the contrast between lipid level and moisture level may be optimal for measuring a particular one of moisture and lipid level. A summary of example frequency ranges suitable for measuring moisture and lipid levels of skin is provided in Figure 4 As shown in the table.

[0053] Thus, in some embodiments, the frequency of the electrical signal generated by the signal generator 106 may determine whether the measured dielectric constant is indicative of the moisture level or lipid level of the skin.

[0054] In some embodiments, the signal generator 106 may be configured to generate an electrical signal at a first frequency in a first frequency range, and the system 100 may be configured to determine the moisture level of the skin based on the dielectric constant measured when the frequency of the signal is the first frequency. In some embodiments, the first frequency range may include frequencies where the contrast between the dielectric constants of wet skin and dry skin is sufficiently high, so that the measured skin dielectric constant is sensitive to the moisture level (or amount of water). In some embodiments, the first frequency range may include frequencies where the contrast between the dielectric constants of lipids and wet or dry skin is low, so that the skin dielectric constant is less sensitive to the lipid level (or amount of lipid). Therefore, in some embodiments, when the frequency of the signal is the first frequency, moisture affects the dielectric constant to a greater extent than lipids. In this way, the value of the dielectric constant at the first frequency depends more on (e.g., more highly on) the moisture content of the skin, and therefore, the dielectric constant at the first frequency (or within the first frequency range) can be used to measure the moisture content more accurately than the dielectric constant at other frequencies (or frequency ranges).

[0055] In some embodiments, the first frequency range may be a frequency range from 10 Hz to 1000 Hz, such as a frequency range from 10 Hz to 900 Hz, such as a frequency range from 10 Hz to 800 Hz, such as a frequency range from 10 Hz to 700 Hz, such as a frequency range from 10 Hz to 600 Hz, such as a frequency range from 10 Hz to 500 Hz, such as a frequency range from 10 Hz to 400 Hz, such as a frequency range from 10 Hz to 300 Hz, such as a frequency range from 10 Hz to 200 Hz. In some examples, the first frequency range may be a frequency range from 10 Hz to 100 Hz, such as a frequency range from 10 Hz to 90 Hz, such as a frequency range from 10 Hz to 80 Hz, such as a frequency range from 10 Hz to 70 Hz, such as a frequency range from 10 Hz to 60 Hz, such as a frequency range from 10 Hz to 50 Hz, such as a frequency range from 15 Hz to 45 Hz, such as a frequency range from 20 Hz to 40 Hz, such as a frequency range from 25 Hz to 35 Hz. In some embodiments, for example, the first frequency may be a frequency selected from 10 Hz, 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz, 70 Hz, 80 Hz, 90 Hz, and 100 Hz. In some examples, the first frequency range may be a frequency range from 100 Hz to 1000 Hz, for example, a frequency range from 150 Hz to 750 Hz, for example, a frequency range from 250 Hz to 650 Hz, for example, a frequency range from 350 Hz to 550 Hz. In some embodiments, for example, the first frequency may be a frequency selected from 100 Hz, 150 Hz, 200 Hz, 250 Hz, 300 Hz, 350 Hz, 400 Hz, 450 Hz, 500 Hz, 500 Hz, 600 Hz, 650 Hz, 700 Hz, 750 Hz, 800 Hz, 850 Hz, 900 Hz, and 1000 Hz.

[0056] Typically, the dielectric constant measured when the frequency of the electrical signal generated by the signal generator 106 is a first frequency can be used to determine the moisture level of the skin using a relationship between the dielectric constant and the moisture level (e.g., water content). In some embodiments, this relationship between the dielectric constant and the moisture level may include an empirical relationship. Typically, a calibration curve or table may be used to convert the dielectric constant measured by the signal generator 106 into a moisture level. Such empirical relationships, calibration curves, and / or tables can be derived by comparing the measured skin dielectric constant with the moisture level. For example, by comparing the measured dielectric constant level with the moisture level measured using a confocal Raman microspectrometer. In some embodiments, the empirical relationship, calibration curve, and / or table may be stored in the memory 104 of the system 100.

[0057] The derivation of empirical relationships, calibration curves and / or tables can be referred to as calibration steps for calibrating the systems described herein. Typically, this calibration step can be performed once for the system and does not need to be repeated. In some embodiments, the calibration step can be performed on a calibration sample (or dotted line). This calibration sample can be, for example, an emulsion made of sebum and moisture. Sebum and moisture can be mixed with known volume fractions, for example using an emulsifier, so as to achieve uniform mixing properties throughout the sample. In some embodiments, the system can be calibrated to other industrial standards, such as to moisture testing (e.g., for moisture levels) and sebum meters (e.g., for lipid levels).

[0058] In some embodiments, signal generator 106 may be configured to generate an electrical signal at a second frequency in a second frequency range, and system 100 may be configured to determine the lipid level of the skin based on the dielectric constant measured when the frequency of the signal is the second frequency.

[0059] In some embodiments, the second frequency range may include frequencies where the contrast between the dielectric constants of wet skin and dry skin is sufficiently low, such that the skin dielectric constant is less sensitive to moisture level (or amount of water). In some embodiments, the second frequency range may include frequencies where the contrast between the dielectric constants of lipids and wet or dry skin is higher, such that the skin dielectric constant is more sensitive to lipid level (or amount of lipid). Therefore, in some embodiments, when the frequency of the signal is the second frequency, lipids have a greater impact on the dielectric constant than moisture. In this way, the dielectric constant value at the second frequency is more dependent on (e.g., more highly dependent on) the lipid content of the skin, and therefore, the dielectric constant at the second frequency (or within the second frequency range) can be used to measure lipid content more accurately than the dielectric constants at other frequencies (or frequency ranges).

[0060] In some embodiments, the second frequency range may be a frequency range from 1kHz to 50kHz, such as a frequency range from 5kHz to 45kHz, such as a frequency range from 10kHz to 40kHz, such as a frequency range from 15kHz to 35kHz, such as a frequency range from 20kHz to 30kHz. For example, in some embodiments, the second frequency range may be a frequency range from 5kHz to 20kHz, such as a frequency range from 5kHz to 25kHz, such as a frequency range from 5kHz to 30kHz, such as a frequency range from 5kHz to 35kHz, such as a frequency range from 5kHz to 40kHz, such as a frequency range from 5kHz to 45kHz, for example, a frequency range from 5kHz to 50kHz. In some embodiments, for example, the second frequency may be a frequency selected from 1kHz, 5kHz, 10kHz, 15kHz, 20kHz, 25kHz, 30kHz, 35kHz, 40kHz, 45kHz, and 50kHz.

[0061] In other embodiments, the second frequency range may be a frequency range from 1 MHz to 100 MHz, such as a frequency range from 1 MHz to 90 MHz, such as a frequency range from 1 MHz to 80 MHz, such as a frequency range from 1 MHz to 70 MHz, such as a frequency range from 1 MHz to 60 MHz, such as a frequency range from 1 MHz to 50 MHz, such as a frequency range from 1 MHz to 40 MHz, such as a frequency range from 1 MHz to 30 MHz, such as a frequency range from 1 MHz to 20 MHz, such as a frequency range from 1 MHz to 10 MHz. In other embodiments, the second frequency range may be, for example, a frequency range from 2 MHz to 10 MHz, such as a frequency range from 2 MHz to 9 MHz, such as a frequency range from 2 MHz to 8 MHz, such as a frequency range from 2 MHz to 7 MHz, such as a frequency range from 2 MHz to 6 MHz, such as a frequency range from 2 MHz to 5 MHz. In other embodiments, the second frequency range may be, for example, a frequency range from 30 MHz to 100 MHz, such as a frequency range from 40 MHz to 90 MHz, such as a frequency range from 50 MHz to 80 MHz. In some embodiments, for example, the second frequency may be a frequency selected from 1 MHz, 2 MHz, 3 MHz, 4 MHz, 5 MHz, 10 MHz, 20 MHz, 30 MHz, 40 MHz, 50 MHz, 60 MHz, 70 MHz, 80 MHz, 90 MHz, and 100 MHz.

[0062] Typically, the dielectric constant measured when the electrical frequency of the signal generated by the signal generator 106 is the second frequency can be used to determine the lipid level of the skin using the relationship between the dielectric constant and the lipid level (e.g., lipid or sebum content). In some embodiments, this relationship between the dielectric constant and the lipid level can include an empirical relationship. Typically, a calibration curve or table can be used to convert the dielectric constant measured by the signal generator 106 into a lipid level. Such empirical relationships, calibration curves and / or tables can be derived by comparing the measured skin dielectric constant with the lipid level. For example, by comparing the measured dielectric constant level with the lipid level measured using a confocal Raman microspectrometer. In some embodiments, the empirical relationship, calibration curve and / or table can be stored in the memory 104 of the system 100.

[0063] The derivation of empirical relationships, calibration curves and / or tables can be referred to as calibration steps for calibrating the systems described herein. Typically, this calibration step can be performed once for the system and does not need to be repeated. In some embodiments, the calibration step can be performed on a calibration sample (or dotted line). This calibration sample can be, for example, an emulsion made of sebum and moisture. Sebum and moisture can be mixed with known volume fractions, for example using an emulsifier, so as to achieve uniform mixing properties throughout the sample. In some embodiments, the system can be calibrated to other industrial standards, such as to moisture testing (e.g., for moisture levels) and sebum meters (e.g., for lipid levels).

[0064] The second frequency range referred to herein is different from the first frequency range (or the first frequency is different from the second frequency). In this way, the system 100 can use different frequencies to determine the moisture level of the skin and the lipid level of the skin, wherein the dielectric constant of the skin is more dependent on (or more affected by) the moisture level or lipid level at the first frequency and the second frequency, respectively, thereby more accurately determining the moisture and lipid levels of the skin. For example, selecting (or selecting) Figure 4 The frequency range shown in , allows one of the components (e.g., lipid or water level) to be determined with less confounding effects of the other components.

[0065] In some embodiments, the system 100 can be configured to measure the dielectric constant at a single frequency to obtain a single dielectric constant measurement. In these embodiments, a single dielectric constant measurement can be used to determine the moisture level or lipid level of the skin. For example, the dielectric constant measurement can be used to determine the moisture level of the skin when the frequency of the generated electrical signal is a first frequency, or the dielectric constant measurement can be used to determine the lipid level of the skin when the frequency of the generated electrical signal is a second frequency. In other embodiments, the system 100 can be configured to measure the dielectric constant at multiple frequencies to obtain multiple dielectric constant measurements. In these embodiments, multiple dielectric constant measurements can be used to determine the moisture level or lipid level of the skin. For example, multiple dielectric constant measurements obtained when the frequency of the generated electrical signal is within a first frequency range can be used to determine the moisture level of the skin, and multiple dielectric constant measurements obtained when the frequency of the generated electrical signal is within a second frequency range can be used to determine the lipid level of the skin.

[0066] In some embodiments where multiple dielectric constant measurements are obtained, system 100 can be configured to determine the moisture level or lipid level of the skin by determining an average moisture level or lipid level of the skin from the multiple dielectric constant measurements. For example, each dielectric constant measurement in the multiple dielectric constant measurements can be used to determine the moisture level or lipid level of the skin (e.g., as described above, depending on whether the frequency of the generated electrical signal is within the first frequency range or the second frequency range). An average of the determined moisture and / or lipid levels can then be determined.

[0067] In some embodiments, the determined lipid level can be used to correct the determined moisture level. Similarly, in some embodiments, the determined moisture level can be used to correct the determined lipid level. For example, if it is known that at a particular frequency, lipids contribute a certain percentage to the value of the measured dielectric constant of the skin, and the lipid level is known, this can be used to determine the amount of dielectric constant that can be attributed to the moisture content of the skin (or vice versa).

[0068] In some embodiments, system 100 can be configured to compare the measured dielectric constant to one or more predefined curves that describe how the dielectric constant of the skin varies with frequency, and determine the moisture level or lipid level of the skin based on the comparison of the measured dielectric constant and the frequency of the radio frequency signal.

[0069] Examples of predefined curves are in Figure 2 Those shown in . Figure 2 The pattern of how the dielectric constant of the skin changes with respect to frequency for different skin characteristics (e.g., high lipid content, high water content, and low water content) is shown. Those skilled in the art will appreciate that Figure 2Only example curves are shown, and the measured dielectric constant level may be compared to a range of curves, for example, to curves representing different moisture levels and lipid levels (eg, combinations of different levels).

[0070] In some embodiments, comparing the measured dielectric constant (e.g., multiple dielectric constant levels) to one or more predefined curves may include comparing the distribution of dielectric constant levels to a shape associated with the predefined curves. For example, the magnitude, slope, or first or second derivative of the dielectric constant measurement may be determined and compared to one or more predefined curves to identify whether the dielectric constant measurement is consistent with the magnitude, slope, or first or second derivative of the predefined curves.

[0071] In some embodiments, the moisture and / or lipid level of the skin can be determined based on a best fit predetermined curve (e.g., a curve representing the best fit of multiple dielectric constant measurements). Those skilled in the art will be familiar with ways to determine the best fit curve for multiple measurements, such as, for example, a least squares fitting method. In this way, multiple dielectric constant measurements can be fit to a known curve to more accurately determine the moisture and / or lipid level of the skin.

[0072] In any embodiments described herein, the system 100 may also be configured to determine a skin condition based on the determined moisture level or lipid level. Figure 5 1 shows how lipid levels (e.g., oiliness) and moisture levels (e.g., hydration levels) can be used to characterize skin as one of several types. For example, dry skin 502 is associated with low lipids and low moisture, dry-oily skin 504 is associated with low hydration and high lipid levels, normal skin 506 is associated with medium moisture levels and lipid levels, hydrated-oily skin 508 is associated with high lipid levels and high moisture levels, and hydrated skin 510 is associated with high moisture levels and low oil levels. In some embodiments, system 100 can determine skin conditions based on the determined combination of moisture and lipids that fall on the graph (or in parameter space), such as in Figure 5 The situation shown in .

[0073] Go to Figure 6According to some embodiments, different combinations of moisture and lipid levels can also be associated with different skin conditions (e.g., dermatological conditions). Skin conditions such as atopic dermatitis show a decrease in skin hydration levels, reflecting a decrease in the skin's ability to retain water, increased transepidermal water loss (TEWL), and defective barrier function. The same symptoms are seen in individuals with psoriasis 606, eczema 614, and ichthyosis vulgaris 604. However, these mentioned conditions show unique skin conditions with respect to the balance between hydration and oiliness. Eczema 614 causes a minor water loss (a few percent) combined with a significant lipid decrease (approximately 25%), while psoriasis 606 shows a significant decrease in hydration (approximately 70%) levels and lipid (approximately 40%-70%) levels. Ichthyosis vulgaris 604 shows a decrease in hydration levels (approximately 63%) without significant changes in the levels of surface skin lipids (approximately ±15%). Skin health is associated with the stability of the function of the skin barrier, which depends on the continuity of the surface lipid structure of the skin. In Figure 6 Other skin conditions indicated in include seborrhea 602 , acne vulgaris 612 , contact dermatitis 608 , and drug rashes (eg, allergies) 610 .

[0074] The lipid phase behavior in the stratum corneum is believed to be critical to the skin barrier function, as it has been found that skin surface lipids act as water regulators in the stratum corneum. Therefore, by determining the moisture and / or lipid levels of the skin in this manner, the system 100 can determine the condition of the skin, and this can be used as an indicator of overall skin health. In some embodiments, the determined skin condition can be presented (or provided, output, or displayed) on a user interface.

[0075] In some embodiments, to further determine the skin condition based on the moisture level or lipid level, the system 100 may also be configured to determine a recommendation for skin treatment based on the determined skin condition. For example, if the system 100 determines that the moisture and / or lipid levels are consistent with a certain skin condition (e.g., eczema), then the system 100 may recommend (or suggest) a topical cream, ointment, or other treatment to improve the skin condition. In some embodiments, the determined recommendation may be presented (or provided, output, or displayed) on a user interface.

[0076] In some embodiments, the system 100 may be connected to a memory (e.g., a data storage device, a database, or a server). For example, the connection may be a wired or wireless connection. In some of these embodiments, after the skin condition has been determined and / or a recommendation for skin treatment has been determined, the system 100 may be configured to send such determinations to the memory. In some embodiments, the system 100 may be configured to determine the lipid and / or moisture levels of the skin at periodic intervals. In some of these embodiments, the system 100 may be configured to store the results at the memory. In this way, the system 100 can track skin conditions and / or determine improvements or changes over time. Therefore, according to some embodiments, the system 100 described herein can quantitatively measure the skin condition before and after treatment by considering changes in skin hydration and lipid levels at different locations and under different climate changes.

[0077] System 100 can provide a non-contact, portable, low-cost and fast solution with the ability to measure both lipid levels and moisture levels of the skin. Thus, system 100 has dual modality. In addition, the measured data storage can enable monitoring and control of skin conditions over time.

[0078] Now go to Figure 7 , a method 700 of operating the system 100 to determine the moisture level or lipid level of the skin is also provided. The system 100 is as previously described. In particular, the system 100 includes at least two electrodes 108 adapted to contact the skin and a signal generator 106 configured to generate an electrical signal at a frequency across the at least two electrodes 108. At box 702, the method 700 includes measuring a dielectric constant between the at least two electrodes 108. At box 704, the method 700 includes determining the moisture level or lipid level of the skin based on the measured dielectric constant and the frequency of the electrical signal. Such steps are described as being performed by the system 100, and the above details will be understood to apply equally to Figure 7 The method at box 702 and box 704 of .

[0079] Also provided is a computer program product comprising a non-transitory computer readable medium having computer readable code embodied therein, the computer readable code being configured such that when executed by a suitable computer or processor, the computer or processor performs any of the methods described herein.

[0080] Therefore, it should be understood that the embodiments described herein are also applicable to computer programs suitable for putting the present invention into practice, especially computer programs on or in a carrier. The program can be in the form of source code, target code, code intermediate source and target code, such as in the form of partial compilation, or in any other form suitable for use in the implementation of the method according to an embodiment of the present invention. It should also be understood that this type of program can have many different architectural designs. For example, the program code that implements the function of the method or system according to the present invention can be subdivided into one or more subroutines. Many different ways of allocating functions between these subroutines will be apparent to those skilled in the art. Subroutines can be stored together in an executable file to form a self-contained program. This type of executable file can include computer executable instructions, for example, processor instructions and / or interpreter instructions (for example, Java interpreter instructions).

[0081] Alternatively, one or more or all of the subroutines may be stored in at least one external library file and linked to the main program statically or dynamically, for example, at runtime. The main program includes at least one call to at least one subroutine. The subroutines may also include function calls to each other. An embodiment relating to a computer program product includes computer executable instructions corresponding to each processing stage of at least one of the methods described herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be linked statically or dynamically. Another embodiment relating to a computer program product includes computer executable instructions corresponding to each device of at least one of the systems and / or products described herein. These instructions may be subdivided into subroutines and / or stored in one or more files that may be linked statically or dynamically.

[0082] The carrier of a computer program may be any entity or device capable of carrying the program. For example, the carrier may include a data storage device, such as a ROM (e.g., a CD ROM or a semiconductor ROM) or a magnetic recording medium (e.g., a hard disk). In addition, the carrier may be a transmissible carrier, such as an electrical or optical signal, which may be transmitted via an electrical or optical cable or by radio or other means. When the program is presented in such a signal, the carrier may be composed of such a cable or other device or apparatus. Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being suitable for executing the relevant method or for use in the execution of the relevant method.

[0083] Those skilled in the art can understand and implement changes in the disclosed embodiments from the study of the drawings, disclosures, and the appended claims when practicing the principles and techniques described herein. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "one" and "an" do not exclude a plurality. A single processor or other unit can implement the functions of several items described in the claims. The fact that certain measures are stated in mutually different dependent claims does not indicate that the combination of these measures cannot be used to advantage. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or solid-state medium provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. Any figure marks in the claims should not be interpreted as limiting the scope.

Claims

1. A system (100) for determining the moisture level or lipid level of skin, the system (100) comprising: at least two electrodes (108) adapted to contact the skin; as well as a signal generator (106) configured to generate an electrical signal across the at least two electrodes (108) at a first frequency in a first frequency range and at a second frequency in a second frequency range, wherein the second frequency range is different from the first frequency range, and the system (100) is configured to: measuring a dielectric constant between the at least two electrodes (108); and determining the moisture level of the skin based on the dielectric constant measured when the frequency of the electrical signal is the first frequency; and / or determining a lipid level of the skin based on a dielectric constant measured when the frequency of the electrical signal is the second frequency; wherein the first frequency range is a frequency range from 10 Hz to 1000 Hz; and Wherein the second frequency range is: A frequency range from 1kHz to 50kHz; or Frequency range from 1MHz to 100MHz.

2. The system (100) of claim 1, wherein the first frequency range is: A frequency range from 10 Hz to 50 Hz; or Frequency range from 150Hz to 750Hz.

3. The system (100) according to any one of claims 1 and 2, wherein the system (100) is configured to measure the dielectric constant at multiple frequencies to obtain multiple dielectric constant measurement values.

4. The system (100) of claim 3, wherein the system (100) is configured to determine the moisture level or lipid level of the skin by determining an average moisture level or lipid level of the skin from the plurality of dielectric constant measurements.

5. The system (100) according to any one of claims 1 and 4, wherein the system (100) is configured to: comparing the measured dielectric constant to one or more predefined curves that describe how the dielectric constant of skin varies with frequency; and The moisture level or lipid level of the skin is determined based on a comparison of the measured dielectric constant to the one or more predefined curves.

6. The system (100) according to any one of claims 1 and 4, wherein the system (100) is further configured to: The skin condition is determined based on the determined moisture level or lipid level.

7. The system (100) according to claim 6, wherein the system (100) is further configured to: Recommendations for skin treatment are determined based on the determined skin condition.

8. A method (700) of determining a moisture level or a lipid level of skin by operating a system (100), the system (100) comprising at least two electrodes (108) adapted to contact the skin and a signal generator (106), the signal generator (106) being configured to generate an electrical signal across the at least two electrodes (108) at a first frequency in a first frequency range and at a second frequency in a second frequency range, wherein the second frequency range is different from the first frequency range, and the method (700) comprising: measuring (702) a dielectric constant between the at least two electrodes; and determining (704) a moisture level of the skin based on the dielectric constant measured when the frequency of the electrical signal is the first frequency; and / or determining (704) a lipid level of the skin based on the dielectric constant measured when the frequency of the electrical signal is the second frequency; wherein the first frequency range is a frequency range from 10 Hz to 1000 Hz; and Wherein the second frequency range is: A frequency range from 1kHz to 50kHz; or Frequency range from 1MHz to 100MHz.

9. A computer program product comprising a computer readable medium having computer readable code embodied in the computer readable medium, the computer readable code being configured to, when executed by a suitable computer or processor, cause the computer or processor to perform the method according to claim 8.

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