JP2018047223A - Arithmetic processing unit for evaluating moisture content of horny cell layer, program, electronic device including arithmetic processing unit, and method for evaluating horny cell layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arithmetic processing unit capable of highly accurately measuring a moisture content of a horny cell layer without changing a state of skin.SOLUTION: An arithmetic processing unit 401 transmits an AC signal emitted from an AC signal generation circuit 410 from an application electrode 201 to skin, and calculates a numerical value representing a moisture content of the horny cell layer on the basis of a skin impedance value of the horny cell layer calculated from the signal detected from the skin and a first variable based on a time difference between the AC signal and a signal transmitting from the application electrode through the skin.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an arithmetic processing device, a program, an electronic device equipped with the arithmetic processing device, and a method for evaluating a stratum corneum moisture amount, and in particular, inputs an AC signal by bringing an electrode into contact with the skin. The present invention relates to an arithmetic processing device for calculating a stratum corneum moisture amount from a measured skin impedance value.

  The configuration of a skin barrier function measuring circuit provided with a conventional arithmetic processing device will be described with reference to FIG. For example, the skin barrier function measuring circuit 800 described in Patent Document 1 includes a display 801, an arithmetic processing device 802, a signal generator 803, an application electrode 804, a detector 805, and a detection electrode 806. Has been. Here, the skin barrier function refers to the action of the skin that prevents foreign substances from entering from the outside of the body, and prevents evaporation of body water and leakage of body fluids. This skin barrier function is thought to mainly affect the water content of the stratum corneum, the thickness of the stratum corneum, and the like.

  The skin barrier function measuring circuit 800 causes the application electrode 804 and the detection electrode 806 to contact the skin, then generates an AC signal with the signal generator 803 and applies the AC signal from the application electrode 804 to the skin. The AC signal generated from the signal generator 803 is detected by the detector 805 via the detection electrode 806 after passing through the skin surface horny layer 807 and the epidermis layer 808 in the skin. The detected signal is subjected to arithmetic processing by the arithmetic processing unit 802 to calculate the skin barrier function and display it on the display 801.

  With reference to FIGS. 13A and 13B, a configuration of an electronic apparatus including a conventional arithmetic processing device will be described. For example, the electronic device 900 described in Patent Literature 2 includes a main body 901 in which an arithmetic processing device is incorporated, a display 902, a probe 903, a detection electrode 904, and an application electrode 905.

  The electronic device 900 generates low-frequency and high-frequency AC signals from the application electrode 905 to pass through the skin, and the passed signal is detected via the detection electrode 904. The detected electrical signal is subjected to predetermined arithmetic processing in the arithmetic processing unit of the electronic device 900, and a susceptance value, an admittance value, and the like are calculated. Based on the calculated susceptance value, admittance value, etc., a characteristic value that can be a skin barrier function is calculated. The characteristic value is displayed on the display unit 902 and used as a numerical value representing the skin barrier function. The conventional electronic device 900 can measure the skin barrier function only by bringing the measurement electrode into contact with the skin for a short time without being affected by the outside air.

  On the other hand, when the stratum corneum moisture content is measured using the above-described conventional electronic device 900 or the like, for example, as described in Patent Document 3, two methods of “capacitance measurement method” and “conductance measurement method” are used. Two methods are known. In any measurement method, an alternating current signal is applied to the skin and the moisture content of the stratum corneum is indirectly measured by paying attention to the electrical characteristics of the stratum corneum.

  Further, since the moisture content of the stratum corneum is deeply related to maintaining skin health, various humectants have been developed for the purpose of maintaining the stratum corneum moisture content. When measuring the moisture content of the stratum corneum in order to measure the sustained effect of the developed moisturizer, measurement is performed using both the “capacitance measurement method” and the “conductance measurement method”. Judging the sustained effect.

  Here, the “capacitance measurement method” is said to be suitable for measurement on relatively dry skin. Further, it is said that the measurement accuracy is high, that is, the variation (σ) between each measurement value is small. The “conductance measurement method” is said to be suitable for measurement on skin with a large amount of moisture, but the measurement accuracy is slightly low, that is, the variation (σ) between each measurement value is said to be large. Yes. “Accuracy” refers to a measure of the degree of variation between measured values when a plurality of measurements are performed.

JP 2003-310567 A JP 2010-172543 A JP 2009-073781 A

  As described above, since there are characteristics of the capacitance measurement method and the conductance measurement method, when measuring the skin condition, both are measured. When measuring using both, for example, after measuring the stratum corneum water content by contacting a capacitance measurement probe with the skin, the conductance measurement probe is brought into contact with the skin to measure the stratum corneum water content. At this time, the capacitance measurement probe is brought into contact with the skin to change the shape of the skin dermis, the moisture retention from the skin between the probe and the skin, the adhesion of the stratum corneum to the probe after the measurement, the probe The skin condition changed due to skin atrophy caused by heat transmitted to the skin. For this reason, in the skin measurement of the conductance measurement method that is measured after the capacitance measurement method, the skin state changes compared to the measurement of the skin of the capacitance measurement method, which is a factor that impedes accurate skin measurement. .

  Also, since the conductance measurement method is used after the capacitance measurement method, the fact that the same location cannot be measured is not consistent with the measurement value obtained by the capacitance measurement method and the measurement value obtained by the conductance measurement method. It was a factor. Furthermore, since the measurement is performed twice by the capacitance measurement method and the conductance measurement method, it takes a lot of time and labor to measure by changing the apparatus.

  This invention is made | formed in view of such a condition, and it aims at providing the arithmetic processing apparatus which can measure a stratum corneum moisture content with high precision, without changing the state of skin.

  In order to solve the above problems, an arithmetic processing apparatus according to an embodiment of the present invention transmits an alternating current signal generated by an alternating current signal generation circuit from an application electrode to the skin, and calculates a stratum corneum calculated from a signal detected from the skin. A numerical value indicating the stratum corneum moisture content is calculated based on the skin impedance value and the first variable based on the time difference between the AC signal and the signal transmitted through the skin from the applied electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the arithmetic processing apparatus which can measure a stratum corneum moisture content with high precision can be provided, without changing the state of skin.

It is a block diagram which shows the electronic device provided with the arithmetic processing apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the probe of the electronic device shown in FIG. (A) is a schematic diagram which shows the cross section of a human skin, (b) is a schematic diagram which shows the cross section of an epidermis in detail. It is a circuit diagram of the stratum corneum moisture content measurement circuit with which the electronic device shown in FIG. 1 is equipped. It is a flowchart which shows operation | movement of the stratum corneum moisture content measuring circuit shown in FIG. It is a graph which shows the 1st implementation result of multiple regression analysis of stratum corneum moisture content. It is a graph which shows the 2nd implementation result of multiple regression analysis of stratum corneum moisture content. It is a graph which shows the 3rd implementation result of the multiple regression analysis of a stratum corneum moisture content. It is a graph which shows the 4th implementation result of the multiple regression analysis of a stratum corneum moisture content. It is a graph which shows the 5th implementation result of the multiple regression analysis of a stratum corneum moisture content. It is a graph which shows the 6th implementation result of the multiple regression analysis of a stratum corneum moisture content. It is a block diagram of the skin barrier function measuring circuit provided with the conventional arithmetic processing unit. (A) is a block diagram which shows the electronic device provided with the conventional arithmetic processing apparatus, (b) is a block diagram which shows the structure of the probe of the conventional electronic device.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the drawings. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly. In the present invention, any one of the following embodiments and modifications thereof may be combined with each other.

(Embodiment 1)
FIG. 1 is a configuration diagram illustrating an electronic apparatus including the arithmetic processing device according to the first embodiment of the present invention. The electronic device 1 illustrated in FIG. 1 includes a main body unit 101, a display unit 102, a probe 103, and a detection electrode 104.

  FIG. 2 is a configuration diagram showing the configuration of the probe 103. A probe 103 shown in FIG. 2 includes a detection electrode 104, an application electrode 201, and a ground electrode 202 in a concentric shape, and is used for evaluating the amount of water in the horny layer in human skin. Here, the ground electrode 202 of the probe 103 prevents external noise from propagating to the detection electrode 104 and the application electrode 201 during measurement, thereby preventing the measurement from being affected by noise. In this embodiment, the electrode interval between the outer diameter of the detection electrode 104 and the inner diameter of the application electrode 201 is 2.2 mm. However, the electrode interval is not limited to this dimension, and the electrode shape is also concentric. Not limited.

  Next, the operation of the electronic device 1 will be described. After turning on the power of the main body 101, the probe 103 on the side surface of the main body 101 is pressed against human skin, and the measurement start switch is turned on so that the detection electrode 104 and the application electrode 201 are in contact with the skin. . Then, the stratum corneum moisture measurement circuit inside the main body 101 is operated, for example, the time difference between the 500 Hz AC signal and the 500 Hz detection signal and the peak value of the 500 Hz detection signal are measured, the phase difference θ, the susceptance value B, An admittance value Y is calculated. Further, for example, the peak value of the 100 kHz detection signal is measured, and the admittance value Y is calculated. Based on the calculated θ, B, and Y, the impedance value of the entire skin is calculated, and the impedance value of the granular layer or less is subtracted from the impedance value of the entire skin to calculate the skin impedance value of the horny layer. The calculation result is displayed on the display unit 102 after being converted into a numerical value representing the stratum corneum moisture content and the like by an arithmetic processing unit described later.

  Here, the skin impedance value of the stratum corneum refers to an impedance value representing the energization characteristics of only the stratum corneum of human skin. Further, when the time difference between the AC signal and the detection signal is Δt and the frequency of the AC signal is f, for example, θ = 2πfΔt can be expressed, and θ is defined as a variable that changes depending on the time difference between the AC signal and the detection signal. (Hereinafter, the relationship between the time difference between the AC signal and the detection signal and θ is the same).

  The configuration of the probe 103 is not limited to the configuration shown in FIG. 2, and any configuration may be used as long as an AC signal can be applied to human skin and a signal passing through the skin can be detected. . Furthermore, the ground electrode 202 need not be used if the influence of external noise during measurement can be reduced. The electronic device 1 is not limited to the above-described configuration, and may be any electronic device such as a mobile phone, a smartphone, or a watch as long as the probe and the stratum corneum moisture measurement circuit can be incorporated.

  FIG. 3A is a schematic diagram showing a cross section of a human skin. The skin 300 is composed of three layers of an epidermis 301, a dermis 302, and a subcutaneous tissue 303 inward from the outer surface of a person. The epidermis 301 is composed of four layers from the upper layer of the outer surface of the person to the horny layer 305, the granular layer 306, the spiny layer 307, and the basal layer 308.

  FIG. 3B is a schematic diagram showing the cross section of the epidermis in detail. The stratum corneum 305 is composed of corneocytes 321 and intercellular lipids 322. The granule layer 306 includes SG1 cells 323, SG2 cells 324, SG3 cells 325, and tight junctions 326 that seal the gaps between the SG2 cells 324.

  Here, the skin barrier function is a function of a living tissue mainly composed of the horny cells 321 in the horny layer 305, the keratinocyte lipid 322, the SG2 cells 324 in the granular layer 306, and the tight junction 326. The skin barrier function restricts the movement of water from the inside to the outside of the skin 300 to prevent the skin from drying. Further, pathogens and allergens are prevented from entering the inside of the skin 300 from outside the skin 300, thereby preventing the skin 300 from being infected. The stratum corneum 305 is responsible for 90% of the skin barrier function, and if the stratum corneum 305 is thinned or the moisture in the stratum corneum 305 is reduced, the skin barrier function is lowered, causing skin dryness or onset of infection. Risk increases.

  As one method for evaluating the skin barrier function, measurement of transdermal water loss (hereinafter sometimes abbreviated as TEWL) has been performed. If TEWL is measured on human skin and it is found that the TEWL value increases, it can be estimated that the stratum corneum is damaged. For this reason, it is thought that the fall of a skin barrier function can be estimated, and measuring TEWL with a human skin is used in order to evaluate a skin barrier function.

  As an example, a procedure for calculating the skin impedance value of the stratum corneum by propagating the AC signal used in this embodiment into the skin 300 will be described. First, the electronic device 1 according to this embodiment is operated, and the measurement start switch is turned on so that the detection electrode 104 and the application electrode 201 of the probe 103 are in contact with the skin 300. Then, for example, the AC signal input to the skin 300 passes through the epidermis 301 and the dermis 302 and reaches the upper layer of the subcutaneous tissue 33, and then returns to the epidermis 301 through the dermis 302. Is detected. Then, based on the detected AC signal, the impedance value of the granular layer 306 and below is subtracted from the impedance value of the entire skin 300 to calculate the skin impedance value of the stratum corneum 305.

  FIG. 4 is a circuit diagram of a stratum corneum moisture content measurement circuit provided in the electronic apparatus 1. A stratum corneum moisture measurement circuit 400 shown in FIG. 4 includes an arithmetic processing unit 401, an AC signal generation circuit 410, a signal detection circuit 420, a determination circuit 430, and a ground terminal 440 connected to the ground electrode 202. Prepare.

  The arithmetic processing device 401 includes output terminals 451, 452, 453, and 465, and input terminals 461, 462, 463, and 464.

  The AC signal generation circuit 410 includes a 500 Hz AC signal generation circuit 411, a 100 kHz AC signal generation circuit 412, and a switching circuit 413. The switching circuit 413 includes input terminals 414 and 415 and an output terminal 416.

  The signal detection circuit 420 includes a 500 Hz output measurement circuit 421, a 100 kHz output measurement circuit 422, a current detection circuit 423, a switching circuit 424, and detection resistors 425 and 426. The 500 Hz output measurement circuit 421 and the 100 kHz output measurement circuit 422 include amplification circuits 471 and 472 and filter circuits 481 and 482, respectively. The switching circuit 424 includes an input terminal 427 and output terminals 428 and 429.

  Next, connection of the stratum corneum moisture measurement circuit 400 will be described. In the arithmetic processing unit 401, the output terminal 451 is connected to the input of the 500 Hz AC signal generation circuit 411, the output terminal 452 is connected to the input of the 100 kHz AC signal generation circuit 412, and the output terminal 453 is connected to the switching circuit 413.

  The output of the 500 Hz AC signal generation circuit 411 is connected to the input terminal 414 of the switching circuit 413, and the output of the 100 kHz AC signal generation circuit 412 is connected to the input terminal 415 of the switching circuit 413. An output terminal 416 of the switching circuit 413 is connected to the application electrode 201.

  In the arithmetic processing unit 401, the input terminal 461 is connected to the output of the amplification circuit 471 in the 500 Hz output measurement circuit 421 and the input of the determination circuit 430, and the input terminal 462 is connected to the output of the determination circuit 430 and the amplification circuit 471. . The input terminal 463 is connected to the output of the amplifier circuit 472 in the 100 kHz output measurement circuit 422 and the input of the determination circuit 430, and the input terminal 464 is connected to the output of the determination circuit 430 and the amplifier circuit 472. The output terminal 465 is connected to the switching circuit 424.

  The input of the amplification circuit 471 in the 500 Hz output measurement circuit 421 is connected to the output of the filter circuit 481, and the input of the amplification circuit 472 in the 100 kHz output measurement circuit 422 is connected to the output of the filter circuit 482. Inputs of the filter circuits 481 and 482 are connected to an output of the current detection circuit 423.

  Further, the detection electrode 104 is connected to the input terminal 427 of the switching circuit 424. An output terminal 428 of the switching circuit 424 is connected to one terminal of the detection resistor 425 and an input of the current detection circuit 423. An output terminal 429 of the switching circuit 424 is connected to one terminal of the detection resistor 426 and an input of the current detection circuit 423. The other terminals of the detection resistors 425 and 426 are connected to the ground terminal 440.

  Next, the operation of the stratum corneum moisture measurement circuit 400 including the arithmetic processing device 401 according to the present embodiment will be described with reference to FIG. When the probe 103 of the electronic device 1 is pressed against the human skin, the operation of the stratum corneum moisture measurement circuit 400 is started.

  First, in step S501, the arithmetic processing unit 401 outputs a control signal, generates a 500 Hz AC signal as a first AC signal from the AC signal generation circuit 410, and applies a 500 Hz AC signal from the application electrode 201 to the skin. To do.

  Next, in step S502, the signal detection circuit 420 measures the 500 Hz detection signal of the detection electrode 104 by the 500 Hz output measurement circuit 421 and converts it into an output signal.

  Next, in step S503, the determination circuit 430 determines whether or not the output signal is a value that can be read by the arithmetic processing unit 401 in the measurement process of the 500 Hz detection signal and the conversion process to the output signal in step S502.

  If the determination circuit 430 determines that the output signal is not readable by the arithmetic processing unit 401, the gain of the amplifier circuit 471 is changed, the process returns to step S501, and measurement is performed again. This remeasurement process is continued until the output signal becomes a value that can be read by the arithmetic processing unit 401. On the other hand, when the output signal becomes a value that can be read by the arithmetic processing unit 401, the process proceeds to step S504.

  In step S504, the arithmetic processing unit 401 obtains, as a result 1, the phase angle θ as the first variable and the first skin impedance based on the time difference between the 500 Hz AC signal and the 500 Hz detection signal and the peak value of the 500 Hz detection signal. A susceptance value B as a value is calculated. Then, the calculated value is stored in a recording medium in the arithmetic processing unit 401.

  Next, in step S505, the arithmetic processing unit 401 outputs a control signal to generate a 100 kHz AC signal, which is a second AC signal, from the AC signal generation circuit 410, and the 100 kHz AC signal from the application electrode 201 to the skin. Apply.

  Next, in step S506, the signal detection circuit 420 measures the 100 kHz detection signal of the detection electrode 104 by the 100 kHz output measurement circuit 422 and converts it into an output signal.

  Next, in step S507, the determination circuit 430 determines whether or not the output signal is a value that can be read by the arithmetic processing unit 401 in the measurement process of the 100 kHz detection signal and the conversion process to the output signal in step S506.

  If the determination circuit 430 determines that the output signal is not readable by the arithmetic processing unit 401, the gain of the amplifier circuit 472 is changed, the process returns to step S505, and measurement is performed again. This remeasurement process is continued until the output signal becomes a value that can be read by the arithmetic processing unit 401. On the other hand, when the output signal becomes a value that can be read by the arithmetic processing unit 401, the process proceeds to step S508.

  In step S508, as a result 2, the arithmetic processing unit 401 calculates an admittance value Y as a second skin impedance value based on the peak value of the 100 kHz detection signal. Then, the calculated value is stored in a recording medium in the arithmetic processing unit 401. Note that either the process from step S501 to S504 or the process from step S505 to S508 may be earlier, and the order can be changed. Further, when calculating the stratum corneum moisture content of the skin surface using the calculation result of only the admittance value Y, the steps from S501 to S504 can be omitted.

  Thereafter, in step S509, the arithmetic processing unit 401 uses the following formula 1 using θ and B stored as the result 1 and Y stored as the result 2 in the case of the region having a large amount of moisture in the stratum corneum. Then, the stratum corneum water content SW (Stratum corneum Water content) 1 is calculated.

[Formula 1]
^{SW1 = a1 × B n / Y} m + a2 × θ + a3 × Y n / B m + a4

  Here, a1, a2, a3, and a4 are predetermined coefficients (constants), and m and n are predetermined variables (constants). Note that a1, a2, a3, a4, m, and n are values appropriately determined by regression analysis. That is, θ, B, and Y are calculated for a plurality of human skins to obtain a plurality of θ, B, and Y. In addition, a product name skin surface horny layer moisture content measuring device (hereinafter referred to as “SKICON”) manufactured by IBS Co., Ltd., which is a device for obtaining the horny layer moisture content by the conventional conductance measurement method for similar skin. To obtain a SKICON value. Regression analysis is performed on a plurality of sets of θ, B, Y, and SKICON values obtained in this way, and predetermined values a1, a2, a3, a4, m, and n used in Equation 1 are determined.

  In the present embodiment, as a result of obtaining θ, B, Y, and SKICON values for the number of people using the skin of a plurality of people, for example, “210522.896” as a1, “1.2726155” as a2, and a3 As “517.176523”, a4 as “−111.04154”, m as “0.5”, and n as “1” (see FIG. 6). By applying these values to Equation 1 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value approximately equivalent to the value measured by the conductance measurement method without measuring the same skin by the conductance measurement method. I can do it.

  According to the above calculation, the correlation R with SKICON has a high value of R = 0.93. The predetermined values a1, a2, a3, a4, m, and n are determined by performing regression analysis on a plurality of sets of θ, B, Y, and SKICON values. A numerical value can be determined.

In Equation 1, B ⁿ / Y ^m and Y ⁿ / B ^m are calculated from the first skin impedance value and the second skin impedance value, and correspond to the second variable of the present invention. It is.

  In step S510, the display unit 102 displays the calculated SW1 value.

  Here, FIG. 6 shows the result of regression analysis of the SW1 value calculated by the above equation 1 and the SKICON value. In FIG. 6, the vertical axis represents the SW1 (calculated SKICON) value, and the horizontal axis represents the SKICON value.

  As can be seen from FIG. 6, a good positive correlation with a correlation R = 0.93 was confirmed between the SW1 value and the SKICON value calculated by Equation 1 above.

  As a modified example, in step S509, the arithmetic processing unit 401 uses the Y stored as the result 2 and stores the stratum corneum moisture amount SW2 using the following equation 2 in the case where the stratum corneum moisture amount is large. Is calculated.

[Formula 2]
SW2 = c1 × (Y) ^c2

  Here, c1 and c2 are predetermined coefficients (constants). Note that c1 and c2 are values appropriately determined by regression analysis. That is, Y is calculated for a plurality of human skins to obtain a plurality of Ys. Further, using the same skin, measurement by SKICON is performed to obtain the SKICON value. Regression analysis is performed on a plurality of sets of Y and SKICON values obtained in this way, and predetermined values c1 and c2 used in Equation 2 are determined.

  In the present embodiment, as a result of obtaining the Y and SKICON values for the number of people using the skin of a plurality of people, for example, numerical values of “11066” as c1 and “0.5863” as c2 are obtained (FIG. 7). By applying these values to Equation 2 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value approximately equivalent to the value measured by the conductance measurement method without measuring the same skin by the conductance measurement method. I can do it.

  According to the above calculation, a high numerical value with a correlation R with SKICON of R = 0.91 was obtained. Since the predetermined values c1 and c2 are determined by performing regression analysis on a plurality of sets of Y and SKICON values, appropriate numerical values can be determined as the number of people increases.

  In step S510, the display unit 102 displays the calculated SW2 value.

  Here, FIG. 7 shows the result of regression analysis of the SW2 value calculated by the above equation 2 and the SKICON value. In FIG. 7, the vertical axis indicates the SKICON value, and the horizontal axis indicates the SW2 (calculated SKICON) value.

  As can be seen from FIG. 7, a good positive correlation with a correlation R = 0.91 was confirmed between the SW2 value and the SKICON value calculated by Equation 2 above.

  As described above, according to the electronic apparatus 1 including the arithmetic processing device 401 according to the present embodiment, the phase angle θ calculated by the arithmetic processing device 401, even in the case where the stratum corneum moisture amount is large, Based on the susceptance value B and the admittance value Y, the SW value having a good correlation with the value measured by the conductance measurement method can be detected.

  Furthermore, since the arithmetic processing unit 401 according to the present embodiment uses the skin impedance value that is a real value in addition to the phase angle θ, the SW value can be calculated more accurately. Therefore, the stratum corneum moisture content on the skin surface can be measured with high accuracy in a wide range of skin conditions such as rough skin where the stratum corneum has been peeled off from a normal state.

  In the electronic apparatus 1 according to the present embodiment, 500 Hz and 100 kHz are used as the frequency of the AC signal, but the frequency of the AC signal is not limited thereto. Furthermore, in the electronic apparatus 1 according to the present embodiment, the 100 kHz AC signal is applied after the 500 Hz AC signal is applied. However, the order in which the AC signal is applied is not particularly limited, and whichever is applied first. Good.

  In the arithmetic processing unit 401 according to the present embodiment, the first susceptance value is used as the first skin impedance value. For example, the admittance value, the conductance value, the susceptance value, the admittance value, and the conductance value are used. An inverse value may be used. Alternatively, as the first skin impedance value, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  Further, in the arithmetic processing unit 401 according to the present embodiment, an admittance value is used as the second skin impedance value. It may be used. Alternatively, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  That is, in the arithmetic processing unit 401 according to the present embodiment, for example, the skin impedance value may be obtained by detecting an admittance value Y from a 500 Hz AC signal and a susceptance value (hereinafter referred to as B100k) from a 100 kHz AC signal. . For example, the skin impedance value may be obtained by detecting a susceptance value (B100k) from a 100 kHz AC signal and a susceptance value from a 500 Hz AC signal.

  In the arithmetic processing device 401 according to the present embodiment, the phase angle θ as the first variable is calculated based on the time difference between the 500 Hz AC signal and the 500 Hz detection signal. Is not particularly limited, and a phase angle θ (hereinafter referred to as θ100k) calculated based on the time difference between the 100 kHz AC signal and the 100 kHz detection signal may be used. In such a case, in Equation 1, θ is changed to θ100k. Then, the SW1 value may be obtained.

  Furthermore, as described above, when the time difference between the AC signal and the detection signal is Δt and the frequency of the AC signal is f, for example, θ = 2πfΔt can be expressed (2π and f are constants). Therefore, θ in Equation 1 can be converted to “Δt”.

(Embodiment 2)
Next, an arithmetic processing apparatus according to the second embodiment of the present invention will be described. The difference between the present embodiment and the first embodiment is that the arithmetic processing apparatus can measure the stratum corneum moisture amount with high accuracy in a region where the stratum corneum moisture amount is small.

  The arithmetic processing apparatus according to the present embodiment has the same configuration as the arithmetic processing apparatus 401 according to the first embodiment, except that the stratum corneum moisture amount is calculated using a mathematical formula different from that of the arithmetic processing apparatus 401 according to the first embodiment. is there. The electronic device according to the present embodiment has the same configuration as the electronic device 1 according to the first embodiment. Therefore, the operation of the stratum corneum moisture measurement circuit including the arithmetic processing apparatus according to the present embodiment will be described using the following Equation 3. In the following description, the same reference numerals as those of the stratum corneum water content measurement circuit 400 according to the first embodiment are used for each configuration of the stratum corneum water content measurement circuit including the arithmetic processing device according to the present embodiment.

  The operation of the stratum corneum moisture content measurement circuit of the present embodiment is the same operation from steps S501 to S508 of the first embodiment shown in FIG. Thereafter, in step S509, the arithmetic processing unit 401 uses the θ, B, and Y stored as the result 1 and the Y stored as the result 2 for the region where the stratum corneum moisture amount is small, and the following formula 3 Is used to calculate the stratum corneum moisture content SW3.

[Formula 3]
^{SW3 = b1 × B n / Y} m + b2 × θ + b3 × Y n / B m + b4

  Here, b1, b2, b3, and b4 are predetermined coefficients (constants), and m and n are predetermined variables (constants). Note that b1, b2, b3, b4, m, and n are values appropriately determined by regression analysis. That is, θ, B, and Y are calculated for a plurality of human skins to obtain a plurality of θ, B, and Y. In addition, for a similar skin, measurement using a portable skin moisture meter (hereinafter referred to as “Mobile Moisture”), a product name of “Courage + Khazaka”, which is a device for obtaining a stratum corneum moisture content by a conventional capacitance measurement method. To obtain the MM value. Regression analysis is performed on a plurality of sets of B, θ, Y, and MM values obtained in this way, and predetermined values b1, b2, b3, b4, m, and n used in Equation 3 are determined. In place of the mobile moisture, measurement using a capacitance measurement method may be performed with a skin moisture meter (hereinafter referred to as “Corneometer”) manufactured by Curage + Khazaka.

  In the present embodiment, as a result of obtaining the θ, B, Y, and MM values for the number of people using the skin of a plurality of people, for example, “−29.25191968” as b1, “0.483169324” as b2, Numerical values of “−5.991675317” as b3, “105.2994447” as b4, “0.25” as m, and “0.125” as n were obtained (see FIG. 8). By applying these values to Equation 3 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value almost equivalent to the value measured by the capacitance measurement method without measuring the same skin by the capacitance measurement method. I can do it.

  According to the above calculation, the correlation R with the MM value was as high as R = 0.89. Note that the predetermined values b1, b2, b3, b4, m, and n are determined by performing regression analysis on a plurality of sets of θ, B, Y, and MM values. A numerical value can be determined.

In Formula 3, B ⁿ / Y ^m and Y ⁿ / B ^m are calculated from the first skin impedance value and the second skin impedance value, and correspond to the second variable of the present invention. It is.

  In step S510, the display unit 102 displays the calculated SW3 value.

  Here, FIG. 8 shows the result of regression analysis of the SW3 value calculated by the above Equation 3 and the MM value. In FIG. 8, the vertical axis indicates the SW3 (calculated mobile moisture) value, and the horizontal axis indicates the MM (Mobile Moisture) value.

  As can be seen from FIG. 8, a good positive correlation with a correlation R = 0.89 was confirmed between the SW3 value calculated by Equation 3 and the MM value.

  As a modification, in step S509, the arithmetic processing unit 401 uses the Y stored as the result 2 and stores the stratum corneum moisture amount SW4 using Y stored as a result 2 in the case where the stratum corneum moisture amount is small. Is calculated.

[Formula 4]
SW4 = d1 × ln (Y) + d2

  Here, d1 and d2 are predetermined coefficients (constants). Note that d1 and d2 are values that are appropriately determined by regression analysis. That is, Y is calculated for a plurality of human skins to obtain a plurality of Ys. In addition, using the same skin, measurement by mobile moisture is performed to obtain an MM value. Regression analysis is performed on the plurality of sets of Y and MM values obtained in this way, and predetermined values d1 and d2 used in Equation 4 are determined. Similarly to the above, instead of the mobile moisture, a measurement by a capacitance measuring method may be performed with a corneometer.

  In this embodiment, as a result of obtaining the Y and MM values for the number of people using the skin of a plurality of people, for example, numerical values of “8.1406” as d1 and “96.509” as d2 were obtained. (See FIG. 9). By applying these values to Equation 4 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value almost equivalent to the value measured by the capacitance measurement method without measuring the same skin by the capacitance measurement method. I can do it.

  According to the above calculation, the correlation R with the mobile moisture has a high value of R = 0.89. Note that the predetermined values d1 and d2 are determined by performing regression analysis on a plurality of sets of Y and MM values, so that appropriate numerical values can be determined according to the increase in the number of people.

  In step S510, the display unit 102 displays the calculated SW4 value.

  Here, FIG. 9 shows the result of regression analysis of the SW4 value calculated by the above equation 4 and the MM value. In FIG. 9, the vertical axis indicates the MM value, and the horizontal axis indicates the SW4 (calculated mobile moisture) value.

  As can be seen from FIG. 9, a good positive correlation with a correlation R = 0.89 was confirmed between the SW4 value calculated by Equation 4 and the MM value.

  As described above, according to the electronic apparatus including the arithmetic processing device according to the present embodiment, the phase angle θ and the susceptance value B calculated by the arithmetic processing device can be obtained even in the region where the stratum corneum moisture amount is small. Based on the admittance value Y, the SW value having a good correlation with the value measured by the capacitance measurement method can be detected.

  According to the electronic apparatus according to the present embodiment, by measuring the skin impedance of the stratum corneum, the SW value having a good correlation with the value measured by the conductance measurement method can be detected in the first embodiment. 2 can detect the SW value having a good correlation with the value measured by the capacitance measuring method. For this reason, the measurement equivalent to both the capacitance measurement method and the conductance measurement method can be performed by one contact with the skin, and the same portion can be measured without changing the skin state. As a result, the stratum corneum moisture content can be measured with high accuracy without changing the skin state by both the capacitance measurement method and the conductance measurement method.

  Further, similarly to the first embodiment, the arithmetic processing apparatus according to the present embodiment uses the skin impedance value that is a real value in addition to the phase angle θ, so that the SW value can be calculated more accurately. Accordingly, the stratum corneum moisture content can be accurately measured in a wide range of skin conditions such as rough skin where the stratum corneum has been peeled off from a normal state.

  In the electronic apparatus according to the present embodiment, 500 Hz and 100 kHz are used as the frequency of the AC signal, but the frequency of the AC signal is not limited to this. Furthermore, in the electronic apparatus according to the present embodiment, the 100 kHz AC signal is applied after the 500 Hz AC signal is applied, but the order in which the AC signal is applied is not particularly limited, and either may be applied first. .

  In the arithmetic processing unit according to the present embodiment, the susceptance value is used as the first skin impedance value. For example, the admittance value, the conductance value, and the susceptance value, the admittance value, and the inverse value of the conductance value are used. May be. Alternatively, as the first skin impedance value, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  Further, in the arithmetic processing device according to the present embodiment, the admittance value is used as the second skin impedance value. For example, the susceptance value, the conductance value, and the susceptance value, the admittance value, and the inverse value of the conductance value are used. May be. Alternatively, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  That is, in the arithmetic processing unit according to the present embodiment, for example, the skin impedance value may be obtained by detecting an admittance value from a 500 Hz AC signal and a susceptance value (hereinafter referred to as B100k) from a 100 kHz AC signal. For example, the skin impedance value may be obtained by detecting a susceptance value (B100k) from a 100 kHz AC signal and a susceptance value from a 500 Hz AC signal.

  In the arithmetic processing device according to the present embodiment, the phase angle θ as the first variable is calculated based on the time difference between the 500 Hz AC signal and the 500 Hz detection signal. The phase angle θ calculated based on the time difference between the 100 kHz AC signal and the 100 kHz detection signal (hereinafter referred to as θ100k) may be used. In such a case, in Equation 3, θ is changed to θ100k. Thus, the SW3 value may be obtained.

  Furthermore, as described above, when the time difference between the AC signal and the detection signal is Δt and the frequency of the AC signal is f, for example, θ = 2πfΔt can be expressed (2π and f are constants). Therefore, θ in Equation 3 can be converted to “Δt”.

(Embodiment 3)
Next, an arithmetic processing apparatus according to Embodiment 3 of the present invention will be described. The difference between the present embodiment and the first embodiment is that the arithmetic processing apparatus can measure the stratum corneum moisture with high accuracy in both the region having a high stratum corneum moisture amount and the region having a small stratum corneum moisture amount. is there.

  The arithmetic processing apparatus according to the present embodiment has the same configuration as the arithmetic processing apparatus 401 according to the first embodiment, except that the stratum corneum moisture amount is calculated using a mathematical formula different from that of the arithmetic processing apparatus 401 according to the first embodiment. is there. The electronic device according to the present embodiment has the same configuration as the electronic device 1 according to the first embodiment. Therefore, the operation of the stratum corneum moisture measurement circuit including the arithmetic processing apparatus according to the present embodiment will be described using Equation 5 below. In the following description, the same reference numerals as those of the stratum corneum water content measurement circuit 400 according to the first embodiment are used for each configuration of the stratum corneum water content measurement circuit including the arithmetic processing device according to the present embodiment.

  The operation of the stratum corneum moisture content measurement circuit of the present embodiment is the same operation from steps S501 to S508 of the first embodiment shown in FIG. After that, in step S509, the arithmetic processing unit 401 stores θ and B stored as the result 1 and 2 as the result 2, regardless of whether the stratum corneum moisture amount is high or low. Using Y, the stratum corneum moisture content SW5 is calculated using the following formula 5.

[Formula 5]
SW5 = a1 × B ⁿ / Y ^m + a2 × θ + a3 × ln (Y) + a4

  Here, a1, a2, a3, and a4 are predetermined coefficients (constants), and m and n are predetermined variables (constants). Note that a1, a2, a3, a4, m, and n are values appropriately determined by regression analysis. That is, θ, B, and Y are calculated for a plurality of human skins to obtain a plurality of θ, B, and Y. In addition, for a similar skin, measurement using a portable skin moisture meter (hereinafter referred to as “Mobile Moisture”), a product name of “Courage + Khazaka”, which is a device for obtaining a stratum corneum moisture content by a conventional capacitance measurement method. To obtain the MM value. Regression analysis is performed on a plurality of sets of B, θ, Y, and MM values obtained in this way, and predetermined values a1, a2, a3, a4, m, and n used in Equation 5 are determined. In place of the mobile moisture, measurement using a capacitance measurement method may be performed with a skin moisture meter (hereinafter referred to as “Corneometer”) manufactured by Curage + Khazaka.

  In the present embodiment, as a result of obtaining θ, B, Y, and MM values for the number of people using a plurality of human skins, for example, “−0.00159” as a1, “0.21592” as a2, Numerical values of “8.74291” as a3, “911.61601” as a4, “1” as m, and “0.125” as n were obtained (see FIG. 10). By applying these values to Equation 5 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value approximately equivalent to the value measured by the capacitance measurement method without measuring the same skin by the capacitance measurement method. I can do it.

  According to the above calculation, the correlation R with the MM value was as high as R = 0.89. Note that the predetermined values a1, a2, a3, a4, m, and n are determined by performing regression analysis on a plurality of sets of θ, B, Y, and MM values. A numerical value can be determined.

In Equation 5, B ⁿ / Y ^m is calculated from the first skin impedance value and the second skin impedance value, and corresponds to the second variable of the present invention.

  In step S510, the display unit 102 displays the calculated SW5 value.

  Here, FIG. 10 shows the result of regression analysis of the SW5 value calculated by the above Equation 5 and the MM value. In FIG. 10, the vertical axis indicates the SW5 (calculated mobile moisture) value, and the horizontal axis indicates the MM value.

  As can be seen from FIG. 10, a good positive correlation with a correlation R = 0.89 was confirmed between the SW5 value and the MM value calculated by Equation 5 above.

  Furthermore, a product name skin surface stratum corneum moisture measuring device (hereinafter referred to as “SKICON”) manufactured by IBS Co., Ltd., which is a device for obtaining the stratum corneum moisture content by the conventional conductance measurement method for similar skin. To obtain a SKICON value. Regression analysis is performed on a plurality of sets of θ, B, Y, and SKICON values obtained in this way, and predetermined values a1, a2, a3, a4, m, and n used in Equation 5 are determined.

  In the present embodiment, as a result of obtaining θ, B, Y, and SKICON values for the number of people using the skin of a plurality of people, for example, “0.034119” as a1, “0.1557” as a2, and a3 "119.4805" as a4, "1086.094" as a4, "1" as m, and "0.125" as n (see FIG. 11). By applying these values to Equation 5 and measuring the skin impedance of the stratum corneum, it is possible to obtain a value approximately equivalent to the value measured by the conductance measurement method without measuring the same skin by the conductance measurement method. I can do it.

  According to the above calculation, the correlation R with SKICON has a high value of R = 0.92. The predetermined values a1, a2, a3, a4, m, and n are determined by performing regression analysis on a plurality of sets of θ, B, Y, and SKICON values. A numerical value can be determined.

  Here, FIG. 11 shows the result of regression analysis of the SW5 value calculated by the above equation 5 and the SKICON value. In FIG. 11, the vertical axis indicates the SW5 (calculated SKICON) value, and the horizontal axis indicates the SKICON value.

  As can be seen from FIG. 11, a good positive correlation with a correlation R = 0.92 was confirmed between the SW5 value and the SKICON value calculated by Equation 5 above.

  As described above, according to the electronic apparatus including the arithmetic processing device according to the present embodiment, even in a region where the stratum corneum moisture amount is large, it is also a case where the stratum corneum moisture amount is small. However, based on the phase angle θ, the susceptance value B, and the admittance value Y calculated by the arithmetic processing device, it is possible to detect the SW value that has a good correlation with the value measured by the capacitance measurement method.

  According to the electronic device according to the present embodiment, by measuring the skin impedance of the stratum corneum, it is possible to detect the SW value having a good correlation with the value measured by the conductance measurement method, and by the capacitance measurement method. It is possible to detect the SW value having a good correlation with the measured value. For this reason, the measurement equivalent to both the capacitance measurement method and the conductance measurement method can be performed by one contact with the skin, and the same portion can be measured without changing the skin state. As a result, the stratum corneum moisture content can be measured with high accuracy without changing the skin state by both the capacitance measurement method and the conductance measurement method.

  Further, similarly to the first and second embodiments, the arithmetic processing apparatus according to the present embodiment uses the skin impedance value that is a real value in addition to the phase angle θ, so that the SW value can be calculated more accurately. it can. Accordingly, the stratum corneum moisture content can be accurately measured in a wide range of skin conditions such as rough skin where the stratum corneum has been peeled off from a normal state.

  In the electronic apparatus according to the present embodiment, 500 Hz and 100 kHz are used as the frequency of the AC signal, but the frequency of the AC signal is not limited to this. Furthermore, in the electronic apparatus according to the present embodiment, the 100 kHz AC signal is applied after the 500 Hz AC signal is applied, but the order in which the AC signal is applied is not particularly limited, and either may be applied first. .

  In the arithmetic processing unit according to the present embodiment, the susceptance value is used as the first skin impedance value. For example, the admittance value, the conductance value, and the susceptance value, the admittance value, and the inverse value of the conductance value are used. May be. Alternatively, as the first skin impedance value, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  Further, in the arithmetic processing device according to the present embodiment, the admittance value is used as the second skin impedance value. For example, the susceptance value, the conductance value, and the susceptance value, the admittance value, and the inverse value of the conductance value are used. May be. Alternatively, a value calculated by selecting two or more values from the group consisting of a susceptance value, an admittance value, a conductance value, and their reciprocal values may be used.

  That is, in the arithmetic processing unit according to the present embodiment, for example, the skin impedance value may be obtained by detecting an admittance value from a 500 Hz AC signal and a susceptance value (hereinafter referred to as B100k) from a 100 kHz AC signal. For example, the skin impedance value may be obtained by detecting a susceptance value (B100k) from a 100 kHz AC signal and a susceptance value from a 500 Hz AC signal.

  In the arithmetic processing device according to the present embodiment, the phase angle θ as the first variable is calculated based on the time difference between the 500 Hz AC signal and the 500 Hz detection signal. The phase angle θ calculated based on the time difference between the 100 kHz AC signal and the 100 kHz detection signal (hereinafter referred to as θ100k) may be used. In such a case, in Equation 3, θ is changed to θ100k. Thus, the SW3 value may be obtained.

  Furthermore, as described above, when the time difference between the AC signal and the detection signal is Δt and the frequency of the AC signal is f, for example, θ = 2πfΔt can be expressed (2π and f are constants). Therefore, θ in Equation 3 can be converted to “Δt”.

  A numerical value or the like indicating the stratum corneum moisture content can also be calculated by installing a program for executing processing in the arithmetic processing device in an electronic device such as a personal computer equipped with the arithmetic processing device according to the present invention.

  The present invention also relates to a method for evaluating the stratum corneum moisture content. In this evaluation method, the AC signal generated by the AC signal generation circuit is transmitted through the skin from the applied electrode, the skin impedance value of the stratum corneum calculated from the signal detected from the skin, and the skin is transmitted from the AC signal and the applied electrode. A first variable based on the time difference of the signal, and a calculation step for evaluating the stratum corneum moisture content.

  Since the evaluation method according to the present invention includes the above-described calculation process, the stratum corneum moisture content can be measured with high accuracy without changing the skin state by a single contact with the skin.

(Example)
An embodiment showing the correlation between the arithmetic processing apparatus to which the present invention is applied, SKICON, and mobile moisture will be described.

  Table 1 shows Examples 1 to 9 in which the correlation between the SKICON and the mobile moisture is calculated in the arithmetic processing apparatus to which the present invention is applied when the range is set to n> m.

  From Table 1, by using Formula 1 in the above arithmetic processing unit, when n> m is set, a very high correlation with the correlation coefficient R = 0.88 or more is obtained with SKICON. I found out that Also, from Table 1, by using Equation 3 in the above arithmetic processing unit, when the value of n is small and when the difference between n and m is small, the correlation coefficient R = 0. It was found to show a very high correlation of 84 or higher.

  Table 2 shows Examples 10 to 15 in which the correlation between the SKICON and the mobile moisture is calculated in the arithmetic processing apparatus to which the present invention is applied when n <m is set.

  From Table 2, by using Equation 3 in the above arithmetic processing unit, when the range of n <m is set, a very high correlation with a correlation coefficient R = 0.80 or more with the mobile moisture It was found that Further, from Table 2, by using Equation 1 in the above arithmetic processing unit, when the difference between n and m is small, the correlation coefficient R = 0.814 or higher with SKICON It was found that

  As shown in the first to fifteenth embodiments, in the arithmetic processing device to which the present invention is applied, the correlation coefficient R = 0.71 or more between SKICON and the mobile moisture by using the mathematical expressions 1 and 3. It was found to show a high correlation. That is, the measured value by the arithmetic processing apparatus to which the present invention is applied can show a high correlation regardless of whether the measured value is measured by either the conductance method or the capacitance method.

  In particular, when n> m is set, or even when n <m is set, if the difference between n and m is small, a very high correlation with SKICON Can be shown. In addition, when n <m is set, or even when n> m is set, if the value of n is small and the difference between n and m is small, the mobile moisture A very high correlation can be shown between them. In addition, since the arithmetic processing apparatus to which this invention is applied has a high correlation with a mobile moisture, it can obtain a high correlation similarly with a corneometer.

DESCRIPTION OF SYMBOLS 1 Electronic device 101 Main body part 102 Display part 103 Probe 104 Detection electrode 201 Applied electrode 202 Ground electrode 300 Skin 301 Epidermis 302 Dermis 303 Subcutaneous tissue 305 Corneal layer 306 Granule layer 307 Spinous layer 308 Basal layer 311 Impedance value 312 of whole skin Impedance value 313 below the stratum corneum skin impedance value 321 corneocytes 322 intercellular lipid 326 tight junction 400 stratum corneum moisture measurement circuit 401 arithmetic processing unit 410 AC signal generation circuit 411 500 Hz AC signal generation circuit 412 100 kHz AC signal generation circuit 413, 424 Switching circuit 414, 415, 427, 461, 462, 463, 464 Input terminal 416, 428, 429, 451, 452, 453, 465 Output terminal 420 Signal detection circuit 421 5 00 Hz output measurement circuit 422 100 kHz output measurement circuit 423 Current detection circuit 425, 426 Detection resistance 430 Determination circuit 440 Ground terminals 471, 472 Amplification circuits 481, 482 Filter circuit

Claims (10)

  The AC signal generated by the AC signal generation circuit is transmitted through the skin from the applied electrode, and the skin impedance value of the stratum corneum calculated from the signal detected from the skin, and the signal transmitted through the skin from the AC signal and the applied electrode And a first variable based on the time difference between the first and second arithmetic processing units for calculating a numerical value indicating the stratum corneum moisture content.   Further, a first skin impedance value based on the first AC signal generated by the AC signal generation circuit and a second skin impedance value based on the second AC signal generated by the AC signal generation circuit are calculated. The arithmetic processing device according to claim 1, wherein a numerical value indicating a stratum corneum moisture content is calculated based on the first variable and the first skin impedance value and / or the second skin impedance value. .   3. The numerical value indicating the stratum corneum moisture content is calculated using the first variable and the second variable calculated from the first skin impedance value and the second skin impedance value. Arithmetic processing unit. The first skin impedance value is one or more values selected from the group consisting of a first susceptance value, a first admittance value, a first conductance value, and their reciprocal values. ,
The second skin impedance value is one or more values selected from the group consisting of a second susceptance value, a second admittance value, a second conductance value, and their reciprocal values. The arithmetic processing device according to claim 2. The first skin impedance value is the first susceptance value,
The second skin impedance value is the second admittance value,
5. The arithmetic processing device calculates a numerical value indicating the stratum corneum moisture content using Equation 1 from the calculated first susceptance value, the first variable, and the second admittance value. The arithmetic processing unit described.
[Equation 1]
Corneum water content ^{= a1 × B n / Y m} + a2 × θ + a3 × Y n / B m + a4
Here, the stratum corneum moisture value is a numerical value indicating the stratum corneum moisture content,
B is the first susceptance value,
Y is the second admittance value,
θ is the first variable,
a1, a2, a3, a4, n, m are constants The first skin impedance value is the first susceptance value,
The second skin impedance value is the second admittance value,
5. The arithmetic processing unit calculates a numerical value indicating the stratum corneum moisture content using Equation 5 from the calculated first susceptance value, the first variable, and the second admittance value. The arithmetic processing unit described.
[Equation 5]
Stratum corneum moisture value = a1 × B ⁿ / Y ^m + a2 × θ + a3 × ln (Y) + a4
Here, the stratum corneum moisture value is a numerical value indicating the stratum corneum moisture content,
B is the first susceptance value,
Y is the second admittance value,
θ is the first variable,
a1, a2, a3, a4, n, m are constants   The arithmetic processing unit according to any one of claims 1 to 6, wherein the numerical value indicating the stratum corneum moisture content is a value measured by a conductance measurement method or a value measured by a capacitance measurement method. An AC signal generation circuit for generating an AC signal;
An application electrode for applying the AC signal;
A detection electrode for detecting a signal transmitted through the skin from the application electrode;
A detection circuit for detecting a signal based on the AC signal and adjusting a waveform;
The arithmetic processing device according to any one of claims 1 to 7,
Electronic equipment comprising.   A program that causes a computer to function as an arithmetic processing unit that calculates a numerical value indicating the stratum corneum moisture content according to any one of claims 1 to 8.   The AC signal generated by the AC signal generation circuit is transmitted through the skin from the applied electrode, and the skin impedance value of the stratum corneum calculated from the signal detected from the skin, and the signal transmitted through the skin from the AC signal and the applied electrode And a first variable based on a time difference between the stratum corneum moisture content.