Skin condition estimation device, skin condition estimation method, and program

Abstract

This disclosure proposes a technology for evaluating skin condition by measuring the properties of the living cell layer of the skin. [Solution] A skin condition estimation device comprising a measuring unit that measures the mobility of water molecules in the living cell layer of a subject's skin, and an estimation unit that estimates the condition of the skin based on the measured mobility.

Description

Technical Field

[0001] The present disclosure relates to a skin condition estimation device, a skin condition estimation method, and a program.

Background Art

[0002] Non-Patent Document 1 discloses that the mobility of water molecules (MWM) represents the hydrogen bond state of water molecules, and the mobility of water molecules in the stratum corneum is related to the arrangement state of intercellular lipids and the amount of natural moisturizing factors.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Skin tissue is mainly composed of three layers: the epidermis, the dermis, and the subcutaneous tissue. The epidermis is composed of the stratum corneum and the underlying living cell layer. The keratinocytes that make up the stratum corneum are dead cells that do not have organelles such as nuclei and mitochondria. The living cell layer of the skin is the site of biological reactions and is located inside the stratum corneum, so it is considered to be involved in the formation of the stratum corneum and the like.

[0005] The present disclosure proposes a technique for evaluating the skin condition by measuring the characteristics in the living cell layer of the skin.

Means for Solving the Problems

[0006] This disclosure provides a skin condition estimation device comprising a measuring unit for measuring the mobility of water molecules in the living cell layer of a subject's skin, and an estimation unit for estimating the condition of the skin based on the measured mobility. [Effects of the Invention]

[0007] According to this disclosure, skin condition can be evaluated by measuring the characteristics of the living cell layer of the skin. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an overview of the skin condition estimation device according to this embodiment. [Figure 2] Figure 2 is a diagram illustrating the hardware configuration of the processing unit in the skin condition estimation device according to this embodiment. [Figure 3] Figure 3 is a diagram illustrating the functional configuration of the skin condition estimation device according to this embodiment. [Figure 4] Figure 4 is a diagram illustrating the functional configuration and processing flow of the skin condition estimation device according to this embodiment. [Figure 5] Figure 5 is a flowchart illustrating the processing in the skin condition estimation device according to this embodiment. [Figure 6] Figure 6 shows an example of a Raman spectrum obtained in the skin condition estimation device according to this embodiment. [Figure 7] Figure 7 illustrates the results of measuring the mobility of water molecules using the skin condition estimation device according to this embodiment. [Figure 8] Figure 8 illustrates the relationship between the difference in the mobility of water molecules calculated using the skin condition estimation device according to this embodiment and the amount of water measured by a keratin moisture meter. [Figure 9] Figure 9 illustrates the relationship between the results of calculating the mobility of water molecules using the skin condition estimation device according to this embodiment and the degree of improvement when a drug is applied. [Figure 10]Figure 10 shows a first example of the results obtained by calculating the mobility of water molecules using the skin condition estimation device according to this embodiment. [Figure 11] Figure 11 shows a second example of the results obtained by calculating the mobility of water molecules using the skin condition estimation device according to this embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, each embodiment of this disclosure will be described with reference to the accompanying drawings. In the description and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals, thereby omitting redundant descriptions.

[0010] This embodiment The skin condition estimation device according to this embodiment will now be described. The skin condition estimation device according to this embodiment comprises a measurement unit that measures the mobility of water molecules in the living cell layer of the subject's skin, and an estimation unit that estimates the condition of the skin based on the measured mobility.

[0011] Mobility of water molecule (MWM) refers to the strength of the bond between oxygen and hydrogen that makes up a water molecule. In other words, it indicates how easily a water molecule moves. Mobility of water molecule is sometimes also called water molecule kinetics. For example, when a water molecule is bonded (hydrogen bonded) to surrounding skin molecules, the vibration of the oxygen-hydrogen bond becomes less likely, and the bond strength increases. That is, the mobility of the water molecule decreases. On the other hand, when a water molecule is weakly bonded (hydrogen bonded) to surrounding water molecules, the vibration of the oxygen-hydrogen bond becomes more likely, and the mobility of the water molecule increases. Furthermore, the vibration frequency is also affected by the structure and state of the molecules to which the water molecule is bonded, so the mobility of water molecule changes depending on the various structures and molecular states of the skin.

[0012] The skin condition estimation device according to this embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing an overview of a skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment.

[0013] The skin condition estimation device 1 measures the mobility of water molecules (MWM) in the living cell layer of the skin OBJ of the subject, and estimates the condition of the skin OBJ of the subject based on the measured mobility.

[0014] The skin condition estimation device 1 includes a Raman spectrum measurement unit 10, a processing unit 20, and a display unit 30. Details of each of the Raman spectrum measurement unit 10, the processing unit 20, and the display unit 30 included in the skin condition estimation device 1 will be described.

[0015] [Raman spectrum measurement unit 10] The Raman spectrum measurement unit 10 measures a Raman spectrum for measuring the mobility of water molecules in the skin OBJ of the subject. The Raman spectrum measurement unit 10 irradiates light on the skin OBJ of the subject by so-called Raman scattering spectroscopy, and detects Raman scattered light scattered from the measurement target. The wavelength of the light irradiated by the Raman spectrum measurement unit 10 is, for example, 671 nanometers. Note that the wavelength of the irradiated light is not limited to 671 nanometers, and may be appropriately selected. Specifically, the wavelength of the irradiated light may be, for example, 633 nanometers. Further, the Raman spectrum measurement unit 10 detects Raman scattered light at a predetermined depth in the skin OBJ of the subject. The Raman spectrum measurement unit 10 is, for example, a confocal Raman spectrometer.

[0016] The Raman spectrum is a scattered light spectrum that appears due to the Raman effect. When light is passed through a substance by the Raman effect, strong elastic scattered light (Rayleigh scattering (the brightest emission line)) having the same wavelength as the incident light and weak inelastic scattered light (Raman scattering (other emission lines)) with a slight wavelength shift from the wavelength of the incident light are scattered.

[0017] The Raman spectrum measurement unit 10 measures the Raman spectrum for each depth ΔD. The depth ΔD is, for example, 2 micrometers. Note that the depth ΔD is not limited to 2 micrometers and may be appropriately selected. Specifically, the depth ΔD may be, for example, 1 micrometer. The i-th depth DPT(i) (where i is an integer of 1 or more) is represented by Equation 1.

[0018] [Number]

[0019] The measurement is performed at least in a range including 60 micrometers or less.

[0020] The Raman spectrum at the depth DPT(i) is represented as the Raman spectrum SPR(i). The Raman spectrum intensity at the wave number σ in the Raman spectrum SPR(i) is represented as SPRI(i, σ).

[0021] The wave number σ in the Raman spectrum measurement unit 10 is, for example, in the range from 2400 per centimeter to 4000 per centimeter. The wave number σ may be discretely acquired, for example, within the above range. Note that the wave number σ in the Raman spectrum measurement unit 10 is not limited to the range from 2400 per centimeter to 4000 per centimeter and may be appropriately selected. Specifically, the wave number σ in the Raman spectrum measurement unit 10 may be, for example, in the range from 1 per centimeter to 100 per centimeter.

[0022] The Raman spectrum measurement unit 10 outputs the Raman spectrum SPR(i) to the processing unit 20.

[0023] [Processing Unit 20] The processing unit 20 processes the Raman spectrum at a predetermined depth output from the Raman spectrum measurement unit 10 to calculate the mobility of water molecules in the skin OBJ of the subject. Then, the processing unit 20 estimates the state of the skin OBJ of the subject based on the calculated mobility of water molecules.

[0024] The hardware configuration of the processing unit 20 will now be described. Figure 2 is a diagram illustrating the hardware configuration of the processing unit 20, which is an example of a skin condition estimation device according to this embodiment.

[0025] The processing unit 20 is, for example, a computer. The processing unit 20 includes a CPU (Central Processing Unit) 21, RAM (Random Access Memory) 22, and ROM (Read Only Memory) 23. The processing unit 20 also includes a storage interface 24i, a communication interface 25i, an external interface 26i, and a display interface 27i. The CPU 21, RAM 22, ROM 23, storage interface 24i, communication interface 25i, external interface 26i, and display interface 27i are each connected to a bus. A storage medium 24 is connected to the storage interface 24i, for example. The Raman spectrum measurement unit 10 is connected to the external interface 26i. The display unit 30 is connected to the display interface 27i.

[0026] The CPU 21 is an arithmetic unit that reads programs (applications) from storage devices such as ROM 23 and storage media 24 onto RAM 22 and executes processing.

[0027] RAM22 is a volatile semiconductor memory that temporarily holds programs (applications), for example.

[0028] ROM23 is a non-volatile semiconductor memory that can retain programs (applications), etc., even when the power is turned off. ROM23 stores programs such as the BIOS that are executed at startup, as well as various settings such as OS settings and network settings.

[0029] The storage interface 24i is an interface to an external storage device such as a storage medium 24. The processing unit 20 uses the storage interface 24i to read from and write to the storage medium 24.

[0030] The storage medium 24 is, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0031] The Communication I / F25i is an interface for connecting to external networks such as the Internet. The Communication I / F25i connects to external networks using, for example, a wired communication method.

[0032] External I / F26i is an interface that connects the processing unit 20 to external devices. External I / F26i is, for example, USB (Universal Serial Bus) or GP-IB (General Purpose Interface Bus).

[0033] The display I / F27i is an interface in the processing unit 20 that connects to an external display device. The display I / F27i is, for example, VGA (Video Graphics Array), DVI (Digital Visual Interface), HDMI (registered trademark) (High-Definition Multimedia Interface), or DisplayPort.

[0034] The processing unit 20 performs various processes described later by executing a program (application) in the hardware configuration described above. Details of the processing unit 20's operations will be described later.

[0035] [Display section 30] The display unit 30 displays the results of calculations performed by the processing unit 20. The display unit 30 is, for example, a liquid crystal display or an organic electroluminescent display.

[0036] <Functional Configuration of the Skin Condition Estimation Device According to This Embodiment> The functional configuration of the skin condition estimation device according to this embodiment will now be described. Figure 3 is a diagram illustrating the functional configuration of skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment.

[0037] The skin condition estimation device 1 comprises a measurement unit 1M, an estimation unit 1E, a result display unit 1F, and a storage unit 1S. The measurement unit 1M comprises a Raman spectrum acquisition unit 1A and a mobility calculation unit 1B.

[0038] [Measurement section 1M] The measurement unit 1M measures the mobility of water molecules in the subject's skin OBJ using Raman spectroscopy. The measurement unit 1M comprises a Raman spectrum acquisition unit 1A and a mobility calculation unit 1B.

[0039] [Raman spectrum acquisition unit 1A] The Raman spectrum acquisition unit 1A acquires the Raman spectrum SPR(i) at a predetermined depth DPT(i) measured for the subject's skin OBJ. The Raman spectrum acquisition unit 1A consists of a Raman spectrum measurement unit 10 and a processing unit 20.

[0040] The processing unit 20 controls the Raman spectrum measurement unit 10 to measure the Raman spectrum of the subject's skin OBJ. The processing unit 20 also acquires the Raman spectrum SPR(i) of the subject's skin OBJ at the depth DPT(i) measured by the Raman spectrum measurement unit 10.

[0041] The processing performed by the processing unit 20 in the Raman spectrum acquisition unit 1A is realized by the CPU 21 executing a program.

[0042] [Mobility calculation unit 1B] The mobility calculation unit 1B calculates the mobility MWM(i) at depth DPT(i) based on the Raman spectrum SPR(i) at depth DPT(i). The mobility calculation unit 1B is composed of the processing unit 20.

[0043] The processing performed by the processing unit 20 in the mobility calculation unit 1B is realized by the CPU 21 executing a program.

[0044] [Estimation section 1E] The estimation unit 1E estimates the skin condition of the subject's skin OBJ based on the mobility MWM(i) at the depth DPT(i) calculated by the mobility calculation unit 1B. The estimation unit 1E is composed of the processing unit 20.

[0045] The processing in the estimation unit 1E, which is executed by the processing unit 20, is realized by the CPU 21 executing a program.

[0046] [Result display section 1F] The result display unit 1F displays the results estimated by the estimation unit 1E on the display unit 30. The result display unit 1F consists of a processing unit 20 and a display unit 30.

[0047] The processing performed by the processing unit 20 in the result display unit 1F is realized by the CPU 21 executing a program.

[0048] [Storage section 1S] The storage unit 1S stores information necessary for processing. The storage unit 1S is composed of a ROM 23 or a storage medium 24 in the processing unit 20.

[0049] <Processing by the skin condition estimation device according to this embodiment> The processing flow in the skin condition estimation device according to this embodiment will be described. Figure 4 is a diagram illustrating the functional configuration and processing flow of the skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment.

[0050] The measurement unit 1M measures the mobility MWM of water molecules in the subject's skin OBJ. The measurement unit 1M then outputs the measured mobility MWM to the estimation unit 1E. The estimation unit 1E estimates the condition of the subject's skin OBJ based on the moisture molecule MWM measured by the measurement unit 1M. The estimation unit 1E then outputs the estimated result RES, which indicates the estimated skin condition, to the result display unit 1F.

[0051] The results display unit 1F displays the results based on the estimated result RES output from the estimation unit 1E.

[0052] Next, the details of the processes performed by the skin condition estimation device according to this embodiment will be explained using skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment. By explaining the processes performed by the skin condition estimation device according to this embodiment, the steps included in the skin condition estimation method by the skin condition estimation device according to this embodiment will be explained. Furthermore, by explaining the processes performed by the skin condition estimation device according to this embodiment, the procedures included in the program to be executed by the computer in the skin condition estimation device according to this embodiment will be explained.

[0053] Figure 5 is a flowchart illustrating the processing in the skin condition estimation device 1, which is an example of a skin condition estimation device according to this embodiment.

[0054] (Step S10) When processing begins, the Raman spectrum acquisition unit 1A in the skin condition estimation device 1 acquires the Raman spectrum of the subject's skin OBJ. The processing unit 20 controls the Raman spectrum measurement unit 10 to acquire the Raman spectrum of the subject's skin OBJ. Specifically, the processing unit 20 controls the Raman spectrum measurement unit 10 to measure the Raman spectrum SPR(i) at depth DPT(i). Then, the processing unit 20 acquires the Raman spectrum SPR(i) measured by the Raman spectrum measurement unit 10.

[0055] The number of Raman spectra SPR(i) to be acquired should be determined as appropriate.

[0056] (Step S20) Next, the mobility calculation unit 1B in the skin condition estimation device 1 calculates the mobility of water molecules MWM(i) at depth DPT(i). Figure 6 shows an example of a Raman spectrum obtained in the skin condition estimation device 1, which is an example of a skin condition estimation device according to this embodiment.

[0057] Figure 6 shows an example of a Raman spectrum when the subject's skin OBJ is human skin. In Figure 6, the horizontal axis is wavenumber (unit: per centimeter), and the vertical axis is spectral intensity (unit: arbitrary unit).

[0058] When the Raman spectrum measurement unit 10 is irradiated with light of a wavelength of 671 nanometers, as shown in Figure 6, the Raman spectrum shows high spectral intensity in the wavenumber range of 3000 units per centimeter to 3700 units per centimeter, due to water molecules. For example, if the energy of molecular vibrations in water molecules is high, the wavenumber of the Raman spectrum increases.

[0059] When irradiated with light of a wavelength of 671 nanometers, the wavenumber band Bs, ranging from wavenumber 3100 to wavenumber 3350, is considered to be the wavenumber band of Raman scattered light scattered by water molecules with low vibrational energy. Therefore, the intensity of the Raman spectrum in wavenumber band Bs represents the intensity due to Raman scattered light scattered by water molecules in a strongly bound state.

[0060] On the other hand, when irradiated with light of a wavelength of 671 nanometers, the wavenumber band Bf in the range of wavenumbers 3350 per centimeter to 3550 per centimeter is considered to be the wavenumber band of Raman scattered light scattered by water molecules with high vibrational energy. Therefore, the intensity of the Raman spectrum in wavenumber band Bf indicates the intensity due to Raman scattered light scattered by water molecules in a weakly bonded state.

[0061] Note that the wavenumber bands Bs and Bf can each be any wavenumber range that divides the wavenumber band where the spectral intensity of water molecules is high into two regions, and are not limited to the range described in this embodiment as long as they are wavenumber positions and ranges that divide the band into two.

[0062] For example, the wavenumber range may be divided into two parts, such as dividing the wavenumber band Bs from 3000 wavenumbers per centimeter to 3350 wavenumbers per centimeter and the wavenumber band Bf from 3350 wavenumbers per centimeter to 3600 wavenumbers per centimeter. Alternatively, in this embodiment, a region with less than 100 wavenumbers per centimeter (not shown) may be used as one of the two divisions.

[0063] Therefore, the mobility calculation unit 1B calculates the mobility MWM(i) by determining the ratio of the Raman spectral intensity SPRIs(i) included in the wavenumber band Bs and the Raman spectral intensity SPRIf(i) included in the wavenumber band Bf at the depth DPT(i).

[0064] The processing in the mobility calculation unit 1B will now be explained. The mobility calculation unit 1B calculates the Raman spectral intensity SPRIs(i) at depth DPT(i) based on Equation 2.

[0065]

number

[0066] Furthermore, the mobility calculation unit 1B calculates the Raman spectral intensity SPRIf(i) at depth DPT(i) based on equation 3.

[0067]

number

[0068] Wavenumber σ1 is the first wavenumber, which is the lower limit of the wavenumbers used to determine that the water molecule bonding state is strong. Wavenumber σ2 is the second wavenumber, which is the upper limit of the wavenumbers used to determine that the water molecule bonding state is strong and the lower limit of the wavenumbers used to determine that the water molecule bonding state is weak. Wavenumber σ3 is the third wavenumber, which is the upper limit of the wavenumbers used to determine that the water molecule bonding state is weak.

[0069] For example, the first wave number is 3100 units per centimeter, the second wave number is 3350 units per centimeter, and the third wave number is 3550 units per centimeter. Note that the first, second, and third wave numbers are not limited to the examples above. For example, the first wave number could be 3150 units per centimeter, the second wave number 3300 units per centimeter, and the third wave number 3600 units per centimeter.

[0070] In the example above, the upper limit of the wavenumber used to determine that the water molecule bonding state is strong and the lower limit of the wavenumber used to determine that the water molecule bonding state is weak are set to the same wavenumber, but they may also be set to different wavenumbers.

[0071] Then, the mobility calculation unit 1B calculates the mobility of water molecules MWM(i) at depth DPT(i) based on equation 4.

[0072]

number

[0073] The above example described the case where the Raman spectral intensity is obtained for a continuous wave number σ. However, when obtained for a discrete wave number σ, the calculation in Equations 2 and 3 is performed by summation rather than integration. Alternatively, the same calculation can be performed by band decomposition using methods such as curve fitting.

[0074] Furthermore, the Raman spectral intensities SPRIf(i) and SPRIs(i) may be normalized by the Raman spectral intensity SPRIb(i), which represents the vibration at the carbon-hydrogen bond (CH) in proteins.

[0075] The Raman spectrum showing vibrations in the carbon-hydrogen bond (CH) in proteins appears in the wavenumber band Bb, from wavenumber 2910 centimeters to wavenumber 2965 centimeters. Therefore, the mobility calculation unit 1B calculates the Raman spectral intensity SPRIb(i) based on equation 5.

[0076]

number

[0077] For example, wavenumber σs1 is 2910 units per centimeter, and wavenumber σs2 is 2965 units per centimeter. Note that wavenumbers σs1 and σs2 are not limited to the above example. For example, wavenumber σs1 could be 2920 units per centimeter, and wavenumber σs2 could be 2970 units per centimeter.

[0078] The mobility calculation unit 1B calculates the normalized Raman spectral intensity SPRIs2(i) at depth DPT(i) based on equation 6.

[0079]

number

[0080] Furthermore, the mobility calculation unit 1B calculates the normalized Raman spectral intensity SPRIf2(i) at depth DPT(i) based on Equation 7.

[0081]

number

[0082] The mobility calculation unit 1B may calculate the mobility using normalized Raman spectral intensity.

[0083] As described above, the measurement unit 1M measures the mobility MWM at multiple depths.

[0084] (Step S30) Next, the estimation unit 1E in the skin condition estimation device 1 estimates the skin condition based on the mobility MWM measured in step S20.

[0085] In step S30, the estimation unit 1E may estimate, for example, water content, transepidermal water loss (TEWL) (barrier function), flexibility, elasticity, enzyme activity, and differentiation state.

[0086] Furthermore, in step S30, as a prediction of future skin condition, the state of the stratum corneum that will be formed later (moisture content, transepidermal water loss, intercellular lipids, natural moisturizing factors, etc.) may be predicted by evaluating the living cell layer. Also, in step S30, as a prediction of effect, the degree of improvement (degree of improvement) due to the application of cosmetics, etc., may be predicted.

[0087] The specific processing steps will now be explained. Figure 7 is a diagram illustrating the processing in skin condition estimation device 1, which is an example of a skin condition estimation device according to this embodiment. Specifically, Figure 7 is a graph showing the mobility of water molecules against the depth measured by skin condition estimation device 1. The horizontal axis of Figure 7 is depth (unit: micrometers), and the vertical axis is the mobility of water molecules (unit: arbitrary unit).

[0088] As shown in Figure 7, there is a curve in the mobility of water molecules from the living cell layer to the stratum corneum. The mobility of water molecules increases from the deeper to the shallower parts of the living cell layer, as indicated by arrow A in Figure 7. On the other hand, the mobility of water molecules decreases significantly in the stratum corneum, as indicated by arrow B in Figure 7.

[0089] We will examine the change in water molecule mobility as it increases from deeper to shallower depths in the living cell layer. Measurement unit 1M measures the first mobility MWM1, which is the mobility at a first depth that shows a peak in water molecule mobility as it increases from deeper to shallower depths, for example, in the range of 14 to 18 micrometers (first depth range D1 in Figure 7). Then, measurement unit 1M measures the second mobility MWM2, which is the mobility at a second depth deeper than the first depth in the living cell layer, for example, in the range of 40 to 44 micrometers (second depth range D2 in Figure 7).

[0090] The first mobility may be, for example, the mobility at a specific depth in the first depth range D1, or the average of the mobility at multiple depths included in the first depth range D1. Alternatively, the first mobility may be a representative or average value of the mobility in the region containing the peak of water molecule mobility. Similarly, the second mobility may be, for example, the mobility at a specific depth in the second depth range D2, or the average of the mobility at multiple depths included in the second depth range D2. Furthermore, the first depth may be the depth just before the mobility decreases towards the surface. In other words, the first mobility may be the mobility at the depth just before the mobility decreases towards the surface.

[0091] Next, we will explain the results of the actual measurements. Figure 10 is a diagram showing the first example of the results of calculating the mobility of water molecules using the skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment. Figure 11 is a diagram showing the second example of the results of calculating the mobility of water molecules using the skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment. Specifically, Figures 10 and 11 are graphs showing the mobility of water molecules against depth measured by the skin condition estimation device 1. In Figures 10 and 11, the horizontal axis is depth (unit: micrometers), and the vertical axis is the mobility of water molecules (unit: arbitrary unit).

[0092] In the first example shown in Figure 10, for example, the first depth range D1 is in the range of 6 micrometers to 10 micrometers, and the second depth range D2 is in the range of 40 micrometers to 44 micrometers. In the second example shown in Figure 11, for example, the first depth range D1 is in the range of 20 micrometers to 24 micrometers, and the second depth range D2 is in the range of 42 micrometers to 46 micrometers.

[0093] The first depth range D1 varies depending on the thickness of the subject's stratum corneum. For example, in people with a thin stratum corneum, the peak may appear shallower than 14 micrometers. Therefore, in people with a thin stratum corneum, the first depth range D1 should be set to a depth shallower than 14 micrometers, for example, 6 micrometers or more. Conversely, for example, in people with a thick stratum corneum, the peak may appear deeper than 14 micrometers. Therefore, in people with a thick stratum corneum, the first depth range D1 may be set to a depth deeper than 14 micrometers, for example, in the range of 20 to 24 micrometers.

[0094] Furthermore, the thickness of the stratum corneum varies not only among subjects but also within the same person depending on factors such as unevenness, the presence or absence of pores, and the location of the skin texture. Therefore, the first depth range D1 may be corrected based on the thickness and structure (unevenness, pores, skin texture, etc.) of the stratum corneum and living cell tissue at the measurement site.

[0095] In summary, the first depth should be set according to the subject, for example, within a range of 6 micrometers to 24 micrometers.

[0096] The estimation unit 1E may determine the degree of change in water molecule mobility, which increases from deeper to shallower in the living cell layer, by calculating the difference ΔMWM between the first mobility MWM1 and the second mobility MWM2. Alternatively, the estimation unit 1E may determine the degree of change in water molecule mobility by calculating the slope of the mobility between the first mobility MWM1 and the second mobility MWM2.

[0097] This section explains the relationship between the difference in mobility ΔMWM calculated using the skin condition estimation device 1 and the skin's moisture content. Figure 8 is a diagram illustrating the relationship between the difference in mobility ΔMWM of water molecules calculated using the skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment, and the moisture content measured by a keratin moisture meter. In Figure 8, the horizontal axis represents the moisture content measured by the keratin moisture meter (unit: arbitrary unit), and the vertical axis represents the difference in mobility ΔMWM of water molecules calculated using the skin condition estimation device 1 (unit: arbitrary unit).

[0098] Figure 8 shows the results of measurements taken four times in spring, summer, autumn, and winter for each of the 27 subjects (14 men and 13 women). The measurement site was the cheek.

[0099] As shown in Figure 8, there was a correlation between the difference in water molecule mobility ΔMWM calculated using the skin condition estimation device 1 and the amount of water measured by the keratin moisture meter.

[0100] Therefore, according to the skin condition estimation device of this embodiment, the amount of moisture in the skin can be estimated by calculating the difference in the mobility of water molecules in the estimation unit. For example, in the estimation unit 1E of the skin condition estimation device 1, which is an example of the skin condition estimation device of this embodiment, the difference in the mobility of water molecules ΔMWM may be measured, and the amount of moisture in the skin may be estimated from the measured difference in the mobility of water molecules ΔMWM.

[0101] Furthermore, in the skin condition estimation device according to this embodiment, the mobility of water molecules may be measured to estimate the degree of improvement due to the application of a drug. Figure 9 is a diagram illustrating the relationship between the results of calculating the mobility of water molecules using the skin condition estimation device 1, which is an example of the skin condition estimation device according to this embodiment, and the degree of improvement when a drug is applied. The horizontal axis of Figure 9 represents the degree of improvement in the visual judgment score. On the horizontal axis of Figure 9, the further to the left, the smaller the degree of improvement, and the further to the right, the larger the degree of improvement. The vertical axis of Figure 9 represents the mobility of water molecules MWM (unit: arbitrary unit) calculated using the skin condition estimation device 1. Specifically, the vertical axis of Figure 9 represents the mobility of water molecules at the first depth in the first depth range D1 in Figure 6.

[0102] Figure 9 shows the results for a total of 30 subjects, in which a cream with wrinkle-improving effects was applied daily for 8 weeks to one outer corner of the eye, and a cream without wrinkle-improving agents was applied daily for 8 weeks to the other outer corner of the eye. Visual evaluation was performed by three evaluators who scored the subjects' faces while comparing them with standard photographs of different wrinkle grades. The scores from the three evaluators were then averaged to obtain the visual evaluation result. The degree of improvement in the visual evaluation was then assessed by the difference in scores before and after cream application.

[0103] Figure 9 shows that a high mobility of water molecules results in a small degree of improvement, while a low mobility of water molecules results in a large degree of improvement. In other words, by measuring the mobility of water molecules, it is possible to predict how much improvement can be achieved through drug application.

[0104] Next, the estimation unit 1E outputs the estimated result RES, which estimates the skin condition, to the result display unit 1F.

[0105] (Step S40) Next, the result display unit 1F in the skin condition estimation device 1 displays the result on the display unit 30 based on the estimation result RES estimated by the estimation unit 1E.

[0106] According to the skin condition estimation device of this embodiment, the condition of the skin can be estimated based on the results of measuring the mobility of water molecules in the living cell layer of the subject's skin. By estimating the condition of the skin based on the results of measuring the mobility of water molecules in the living cell layer of the subject's skin, the skin condition estimation device of this embodiment can evaluate the skin condition. The stratum corneum of the epidermis is in contact with the outside and is therefore affected by the external environment. The living cell layer is located inside the stratum corneum and is therefore less affected by the external environment. Since the living cell layer is less affected by the external environment, the skin condition estimation device of this embodiment can evaluate the skin condition by measuring the condition of the living cell layer.

[0107] The skin condition estimation device according to this embodiment can evaluate skin condition using a new indicator called water molecule motility (water molecule mobility). Since water molecule motility (water molecule mobility) is considered to be an indicator that reflects various skin conditions, it is thought to be an indicator that also reflects the amount of natural moisturizing factors and the state of intercellular lipids. Furthermore, water molecule motility (water molecule mobility) in the living cell layer is thought to be involved in various biological reactions. Therefore, it is thought that by evaluating skin condition using a new indicator according to this embodiment, new insights can be gained, utilized in product information, and used in new diagnostic technologies.

[0108] The skin condition estimation device according to this embodiment can provide a comprehensive evaluation index for current and future skin condition. Furthermore, by combining the skin condition estimation device according to this embodiment with near-infrared sensing, for example, simple diagnosis and in-store use are possible. In addition, the skin condition estimation device according to this embodiment can provide feedback on whether one's score is good or bad in relation to the overall average and variance. Moreover, the skin condition estimation device according to this embodiment can calculate a predicted value indicating the degree of improvement that can be expected.

[0109] This disclosure is not limited to the examples given above, but is intended to include all modifications within the meaning and scope of the claims, as shown in the claims. [Explanation of Symbols]

[0110] 1. Skin condition estimation device 1A Raman spectrum acquisition section 1B Mobility calculation section 1E Estimation Unit 1F Result display area 1M measuring section 1S storage section 10. Raman Spectrum Measurement Section 20 Processing Units 30 Display section MWM Mobility OBJ skin RES estimation results SPR Raman Spectrum SPRIb, SPRIf, SPRIs Raman spectral intensity SPRIf2, SPRIs2 Normalized Raman Spectrum Intensity ΔD depth

Claims

1. A measuring unit that measures the mobility of water molecules in the living cell layer of the subject's skin, An estimation unit that estimates the condition of the skin based on the measured degree of mobility, Equipped with, Skin condition estimation device.

2. The measurement unit measures the first mobility, which is the mobility at a first depth in the living cell layer, and the second mobility, which is the mobility at a second depth deeper than the first depth in the living cell layer. The estimation unit estimates the amount of moisture in the skin based on the difference or slope between the first degree of mobility and the second degree of mobility. The skin condition estimation device according to claim 1.

3. The estimation unit estimates that the moisture content is high when the difference or slope is large. The skin condition estimation device according to claim 2.

4. The first depth is the depth just before the degree of mobility decreases toward the surface, or a depth in the range of 6 micrometers to 24 micrometers. The second depth is 18 micrometers or more, or in the range of 40 to 44 micrometers. A skin condition estimation device according to either claim 2 or claim 3.

5. The estimation unit estimates the degree of improvement when the drug is applied, based on the degree of mobility. The skin condition estimation device according to claim 1.

6. The estimation unit estimates that the degree of improvement is large when the degree of mobility is low. The skin condition estimation device according to claim 5.

7. The measurement unit measures the degree of mobility by Raman spectroscopy. The skin condition estimation device according to claim 1.

8. (a) A step of measuring the mobility of water molecules in the living cell layer of the subject's skin, (b) A step of estimating the condition of the skin based on the measured degree of mobility, including, Method for estimating skin condition.

9. In step (a) above, the first mobility, which is the mobility at a first depth in the living cell layer, and the second mobility, which is the mobility at a second depth deeper than the first depth in the living cell layer, are measured. In step (b) above, the amount of moisture in the skin is estimated based on the difference between the first degree of mobility and the second degree of mobility. The method for estimating skin condition according to claim 8.

10. In step (b) above, the degree of improvement when the drug is applied is estimated based on the mobility. The method for estimating skin condition according to claim 8.

11. On the computer, Procedure for obtaining the mobility of water molecules in the living cell layer of the subject's skin, A procedure for estimating the condition of the skin based on the acquired degree of mobility, A program to execute.

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