JPH10118041A - Apparatus for metering skin resistance and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate influence of contact resistance by an apparatus wherein various metering parameters such as skin resistance when skin is brought into contact with are calculated by both ends electric voltage obtd. from a plurality of metering resistances detecting both ends electric voltage of a pair of skin contacting electrodes by switching successively and alternately each resistance and feeding it. SOLUTION: Electrically conductive minerals A and B covering the surfaces of electrically conductive cylindrical rollers (skin contacting electrodes) 1 and 2 and a metering circuit 100 in which an potential difference metering resistance 4 is built are ohmicly connected with conductive wirings 10 and 11 and a shaft mechanism. While a handle part of a box body is handled, the electrically conductive cylindrical rollers 1 and 2 are simultaneously brought into skin-contact with specified sites of the skin 3 of a living body to measure external electric voltage generated between the electrically conductive cylindrical rollers 1 and 2. In this time, an electronic switch 12 is worked to feed potential difference metering resistances 4 by switching successively them one by one from R1 to the metering circuit 100 and on every time, potential difference on both ends of the metering resistance is read out and is transferred to a storing and operating part 7 and the numeral obtd. is digitally displayed on a displaying part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument capable of locally measuring a skin resistance value corresponding to the physiological activity of living skin and a method therefor.

[0002]

2. Description of the Related Art Conventionally, as one of means for measuring skin resistance, a method of obtaining a current value flowing when a DC or AC voltage is externally applied between a pair of electrodes placed at a fixed interval on the skin. There is. Also disclosed is a method called an electrocardiograph, in which an indifferent electrode is gripped, an alternating current is applied while the relevant electrode is slid on the skin, and a low-resistance, high-capacity point (so-called acupoint) is searched from surrounding parts. (Japanese Patent Application No. 37-20831)
issue). These are all methods of applying electricity to the living body using an external power supply, and at this time, the skin constitutes the external impedance of the power supply circuit.

[0003] On the other hand, the present inventors have insulated skins of different kinds of conductive minerals, and when they are electrically connected to each other at a non-skinned portion, the skin exhibits an electrolytic action to constitute a chemical battery. Utilizing the principle, there has been disclosed a sensor for measuring skin resistance having a structure in which the heterogeneous conductive minerals are maintained at a constant interval and connected to a DC potentiometer (Japanese Patent Application No. 62-73334). This sensor utilizes the fact that the theoretical electromotive force value generated between different types of conductive minerals is constant once the combination is determined. Because the magnitude of the internal loss (resistance loss) of the battery varies, the phenomenon that the battery voltage measured outside the battery reflects the physiological activity is captured. In this case, the skin constitutes the internal impedance of the power supply circuit.

In the above-mentioned external power supply system, if the distance between the electrodes in contact with each other is small, a large current flows when the electrodes are short-circuited due to sweating or the like, which is dangerous. Conversely, if the distance between the electrodes in contact with the skin is long, the signal becomes weak. In addition to being susceptible to noise, there is a drawback that errors are increased due to fluctuations in the internal potential caused by unexpected fluctuations in the intracutaneous conduction path. On the other hand, in the internal impedance method using the bioelectrode, even if the electrode interval is narrowed, energization is automatically stopped at the time of a short circuit between the electrodes, so that it is safe.

[0005]

In the above-described conventional skin-resistance measuring apparatus of the electrode-contact type, the skin current-carrying path is formed so as to include not only the genuine skin area and the subcutaneous tissue but also the contact resistance. Have been. In order to suppress the influence of the contact resistance, some measures were required, such as puncturing the electrode into the skin or applying a liquid material having high conductivity between the electrode and the skin for measurement.
However, such a method is a major obstacle to easily measuring the resistance of each part of the skin.

The contact resistance value at the time of skin contact varies greatly depending on the condition of the living skin and the physiological activity, but generally takes a very large value (several to several tens MΩ). Since the skin resistance itself is considerably large in the fat layer and stratum corneum in the epidermis region, if the skin layer is removed and the electrode is exposed to the granular layer or spinous layer, contact can be significantly reduced along with skin resistance (Digit of several tens KΩ). However, if the stratum corneum is artificially removed for measurement, not only will the subject be distressed, but also the risk of virus infection and the like will occur. Therefore, this method cannot be used except in special cases.

The present inventors obtained comparatively reproducible data in the soft skin region of a young subject during a measurement experiment using the above-described skin resistance measurement sensor using a bio-battery. In general, they have experienced low reproducibility in the measurement of affected parts and the elderly.

[0008] In recent years, as women and the elderly have increased their social advancement and going out, interest in skin beauty has significantly increased. To maintain or improve the "freshness" of the skin, it is important to use daily care for moisturizing and use of osmotic agents to improve the moisture content of the epidermal tissue. Generally, skin aging or disease is recognized only when wrinkles, spots, cracks, or pain occur to the extent that they can be discerned by the naked eye. However, from a cosmetic point of view, improvement is difficult without care for the aging phenomenon that progresses in the previous stage.
In this case, identifying the physiological activity of the skin is a powerful weapon as a measure to know the degree of aging and the degree of improvement. In order to easily discriminate them in daily life, it is convenient if the resistance value of the skin reflecting the physiological activity can be known.

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple and reproducible skin resistance measuring apparatus and method which eliminates the above-mentioned disadvantages of the conventional electric skin resistance measuring instrument and eliminates the influence of contact resistance. It is to be.

[0010]

According to the present invention, a pair of skin contact electrodes, each of which is made of a conductive mineral whose skin contact surface has a different standard monopolar potential, is disposed at a fixed distance between the skin contact surfaces, Each of the resistors has a different resistance value, and each resistor is switched alternately and sequentially turned on to detect a voltage between both ends of the pair of skin contact electrodes. A measurement device for measuring various parameters such as skin resistance at the time of skin contact from a voltage between both ends is disclosed.

Further, the present invention provides a skin resistance measuring apparatus in which the conductive mineral constituting at least the skin contact surface of a pair of skin contact electrodes is a combination of an n-type semiconductor and a metal having a higher standard monopolar potential. Disclose.

Further, the present invention discloses an apparatus for measuring skin resistance in which the measurement parameters are at least one of skin resistance, skin contact resistance, skin leakage resistance, skin current value, and skin skin loss voltage.

Further, the present invention provides a method for fixing a pair of skin-contacting electrodes, each of which has a skin-contacting surface made of a conductive mineral having a different standard monopolar potential, at a predetermined interval and simultaneously performing skin-contacting with the pair of skin-contacting electrodes. The voltage values V ₁ , V ₂ , V ₃ ,... Measured when the potential difference measuring resistors R having ohmic junctions between the contact electrodes are sequentially switched to R ₁ , R ₂ , R ₃ ,. The first step of storing, and the generated electromotive voltage of a chemical battery in which the pair of skin contact electrodes (positive and negative electrodes) are formed on the skin of a living body is E, the intracutaneous resistance giving an internal loss of the chemical battery is R _d , When the skin leakage resistance between the pair of skin contact electrodes is R _s and the sum of the skin contact resistances of the pair of skin contact electrodes is R _c , V _i = R _i (R _s + R _c ) E / (R _s ) _{+ R c) (R d +} R c + R i) + (R d + R c) R i, as here i = 1, 2, 3 ... made multiple simultaneous side Solve R _s, and a second step of calculating the specifications such as R _d, R _s, and a third step of selectively displaying specifications, such as R _d, a more composed of skin resistance measurement method Disclose.

When a pair of conductive minerals having different standard unipolar potentials are conductively joined to each other at the non-skin contact portion and the pair of conductive minerals are simultaneously in skin contact with each other, a chemical battery is formed to cause a redox reaction. As a result, an electromotive force (voltage E) is generated. When the distance between the pair of skins contact electrodes made of dissimilar conductive minerals constant, the resistance R _d of intradermal redox reaction occurs is determined by the conductivity and reaction occurs velocity of ions produced primarily by redox, R _d decreases as the physiological activity of the skin increases (the ionic conductivity in the skin and the rate of occurrence of the reaction increase). R _d gives the internal loss of the chemical battery, and when the current flowing between the electrodes (intracutaneous current value) is I, a voltage (E−R _d · I) becomes an external voltage between the pair of skin contact electrodes. Is output. Since E is essentially determined by the combination of materials, this external voltage gives an index corresponding to the bioactivity of the skin.

When a conductive mineral having a lower standard monopolar potential constituting the negative electrode of a chemical battery is formed of an n-type semiconductor, holes generated in the negative electrode by power generation due to the action of a Schottky barrier formed on the skin contact surface. It is quickly drifted to the skin contact surface and released into the skin. This maintains the electrical neutrality of the negative electrode, and prevents the penetration of electrons and negative ions from the skin into the negative electrode by the Schottky barrier. For this reason, the passivation phenomenon of the negative electrode, that is, the phenomenon in which the negative electrode skin contact surface combines with OH ^- ions generated in the skin to form a hydroxide and electrically insulate can be prevented. Therefore, a stable electromotive force can be generated for a long time. R _d and epidermal leakage resistance R _s from simultaneous linear equations by sequentially switching using measuring resistance value incorporated in the measuring circuit, it is possible to obtain the internal loss R _d · I.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle and embodiments of the present invention will be described below in detail. FIG. 2 shows a state in which the hand-held skin resistance measuring device of the present invention is in skin contact. FIG.
(A) is present on the skin-contacting surface and the skin side when a pair of skin-contacting electrodes made of different kinds of conductive minerals (the electromotive force generated as a chemical battery formed on living skin is E) are simultaneously skinned. FIG. 2B is a diagram showing resistance, and FIG. 2B is an equivalent circuit diagram of direct current with respect to FIG. In FIG. 2 (A), R _c1 and R _c2 are skin contact resistance, R _d is intradermal resistance, R _s is skin surface leakage resistance,
100 indicates a measurement circuit. Since R _c1 and R _c2 are components connected in series, it can be expressed as R _c = R _c1 + R _c2 . Measurement circuit 1
00 denotes a plurality of parallel resistors R (R ₁ , R ₂ ,...)
And measurement processing means for performing measurement, storage, calculation, and display. The parallel resistance can be put on the circuit at the time of measurement for each one. FIG. 2 (B) (not illustrated measuring means) showing a case in which charged so as to connect the R ₁ on the circuit of the plurality of potential difference measuring resistor R incorporated in the measuring circuit. In addition, for simplicity, a capacitance component acting during a transient phenomenon is not illustrated. As shown in FIG. 2 (B), the in the state in which a pair of skin contact electrodes are simply pressed onto the skin, Kawase' resistance _{R c (= R c1 + R} c2) is added to the circuit resistance. Further believed to leakage resistance R _s of the skin surface is connected in parallel with the measuring resistor R _1. The same applies to the measuring resistors R ₂ and R ₃ . When the resistors R _{1 to} R ₃ are turned on, the voltages V ₁ , V ₂ ,
V ₃ is measured by the measurement processing means, and the unknowns R _s , R _d , R _c and the intracutaneous current value I are calculated and displayed. Where R _s ,
The calculation formulas for R _d , R _c , and I are as follows. When Kirchhoff's law is applied to the equivalent circuit of FIG.

(Equation 1) The following expression holds. Assuming that the measuring resistors R incorporated in the measuring circuit 100 are switched from R ₁ to R ₂ and R ₃ and are supplied one by one to the circuit, and the measurement potential differences V ₂ and V ₃ are obtained each time,
Similarly to (Equation 1),

(Equation 2)

(Equation 3) The following expression is obtained.

Since E is determined by the combination of materials and is constant, the measurement processing means simultaneously solves (Equation 1) to (Equation 3) to convert the unknowns R _s , R _d and R _c into V ₁ and V _2. ,
Determined as a function of V ₃ , E, R ₁ , R ₂ , R ₃ . The other intradermal current values I of these unknowns are also determined. Particularly important as an index of the physiological activation of the skin is the internal loss voltage R _d · I of the battery at the position where the chemical battery is formed as described above. This value obtained by applying Kirchhoff's law is

(Equation 4) Thus, the calculation can be performed immediately by substituting R _d obtained from (Equation 1) to (Equation 3) into (Equation 4). This is also executed by the measurement processing means.

Hereinafter, embodiments will be described. FIG. 1 (A)
1 shows a main configuration of a skin resistance measuring device according to an embodiment of the present invention. In FIG. 1 (A), reference numerals 1 and 2 denote electrically conductive mineral rollers having different standard monopolar potentials, and electrically conductive cylindrical rollers (skin-contact electrodes) whose surfaces are covered with a second electrode. Measurement circuit 1 with built-in 4
00 means the wires 10, 1 regardless of whether the roller is rotating or stationary.
An ohmic connection is made by a shaft mechanism 1 and a shaft mechanism (not shown). Kooto may use different metals such as gold and chromium, but have a higher standard unipolar potential such as gold and zinc oxide or platinum and germanium, and an n-type semiconductor having a lower standard unipolar potential. Is more preferable from the viewpoint of device stability. In particular, when an oxygen-deficient material such as zinc oxide, tin oxide, manganese oxide, or aluminum oxide is selected as the n-type semiconductor, even if the material is repeatedly used in a humid atmosphere, the thickening of the oxide film only occurs, and the electromotive force is reduced. Often stable.

In FIG. 1 (A), reference numeral 3 denotes a living skin, and 4 denotes a potential difference measuring resistor R composed of different resistors having at least three different resistance values R ₁ , R ₂ , R ₃ ,. . The measuring circuit 100 has, in addition to 4, the measuring processing means 101 including the measuring unit 6, the storage / operation unit 7, the display unit 8, and the electronic switch 12. 9 is a measuring circuit 1
A power supply for 00 (usually a battery), 13 is a housing, and 14 is an external switch. FIG. 1B shows four parallel switches SW.
_Although an example in which _{1 to} SW ₄ are provided is shown, the function is the same as that of FIG. The conductive cylindrical rollers 1 and 2 are simultaneously in contact with a predetermined portion of the living skin 3 while gripping the handle of the housing 13, and the external switch 14 is operated to turn on the power supply 9 to the measuring circuit 100, and the conductive cylinder The external voltage appearing between the rollers 1 and 2 is measured. At this time, the electronic switch 12 is worked measuring circuit is turned by switching one by resistor R 1 month electric potential difference measuring from R _1, the potential difference V _i of each case measured resistance across is read. The measured V _i is immediately sent to the storage / calculation unit 7 and stored, and R _d , R _s , R _c , I, and R _d · I obtained by calculation according to (Equation 1) to (Equation 3). Are stored. These numerical values are selectively digitally displayed on the display unit 8 by operating the external switch 14. FIG. 2 (A)
The skin contact resistances R _c1 and R _c2 of each electrode shown in FIG. 2 are considered to be almost the same in the vertical direction and the horizontal direction of the normal skin, and FIG.
It is sufficient to consider a DC equivalent circuit such as (B) (R
_c = _Rc1 + _Rc2 ). In this case, the potential difference measuring resistor R is 3
(Resistance values R ₁ , R ₂ , R ₃ ). However, depending on the electrode shape and skin condition may have to be taken into account that it has a different value R _cv, R _cH in R _c is the vertical and horizontal directions of skin. In this case, one more resistance (resistance value R ₄ ) must be added as a potential difference measurement resistor to solve the quaternary simultaneous equations for V _{1 to} V ₄ . In addition,
At this time, R _cv connected in series to R _d in FIG.
The skin contact resistance connected in series with R _s is R _cH . When the necessary display is completed, the stored numerical value is reset by operating the external switch 14.

Healthy male and female subjects in their teens, forties, 60
Five subjects were selected for each subject, and the above measurement was performed on the skin of the right back of each subject, and the average intradermal voltage drop (ie, the internal loss of the chemical battery, R _d · I using the display of FIG. 2) was obtained for each group. ) Are shown in Table 1. In the case of this example, gold and zinc oxide were respectively selected as the conductive minerals A and B which constitute the skin-contacting portions of the conductive cylindrical rollers 1 and 2, so that the generated electromotive voltage of the chemical battery is E = 2.3 (V ). The values of the potential difference measuring resistor R are as follows: R ₁ = 150 MΩ, R ₂ = 100 MΩ, R ₃
= 50 MΩ.

[0021]

[Table 1] Table 1 clearly shows that the voltage drop in the skin increases with aging. In the same age group, males have higher voltage drops than females. This may be related to the presence of a subcutaneous fat layer, but the mechanism of action is not clear. Since the subcutaneous voltage drop is affected by the ionic conductivity and the rate of occurrence of the redox reaction in the skin under the electrode, it is considered that the lower the metabolism of the skin, the smaller the subcutaneous voltage drop.

[0022] The physiological activity of the skin varies among individuals besides age.
It is thought that there are seasonal differences and time differences. Of course, even the same solid has a size depending on the skin site, and generally the thicker skin portion has lower bioactivity than the softer portion and the exposed portion has lower bioactivity than the portion covered with clothing. It is easy to estimate the solid skin age by measuring a specific part such as face or hand that is always exposed by the device of the present invention, or to observe the effect of improving the bioactivity by a cosmetic agent. Now you can do it.

Assuming that the skin contact resistance is different between the vertical and horizontal directions of the skin (R _{cv cvR cH} ), FIG.
The R _c are connected in series R _d of (B) to the R _cv, also R _s
In replacing the R _c are connected in series R _cH, further added 1 month as potential difference measuring resistor (R ₄ = 10MΩ), obtains the V ₁ ~V ₄ at the same skin site of Table 1 subject, four R _d · I was calculated by solving the simultaneous equations. When the obtained numerical values (not shown) are compared with the data of Table 1, both values fall within the range of ± 50%, and as long as a relatively flat skin site is measured using the apparatus of FIG. It was confirmed that R _cv = R _cH = R _c may be set. In general, when the contact area was small and the skin contact pressure was increased, _there was a tendency that R _cv ≠ R _cH .

On the other hand, wrinkles and roughness of the skin are considered to be aging of the epidermis, and the main cause is the dissipation of water from the surface layer of the skin. If the water content decreases and the “freshness” is lost, the stratum corneum becomes rough and cracks. Roughness proceeds inward, and when the stimulus reaches the peripheral nerves distributed in the subcutaneous tissue, it is sensed in the cerebrum. However, it is difficult for peripheral nerves to sense the initial "skin roughness" occurring on the very surface of the skin.
When the temperature is low and the metabolism of the skin is low in a dry climate in winter or when the wind is strong, “skin roughness” is particularly remarkable. It is effective to use a skin leakage resistance R _s as an index associated with the surface moisture content of the skin.

Using the measuring device shown in FIG.
0's, 40's, the voltage V ₁ ~V ₃ was measured at a specific point of the skin of the right cheek 60 per Adult Women five, simultaneous equations send it to the storage and computing unit (number 1) through (3) R _s was determined from the solution at. Table 2 shows the results obtained in January in winter and August in summer.
Shown in R _s in the table is an average value of 5 persons in each group.
Table 2 shows that in each age, the water content of the epidermis is significantly higher in summer than in winter. However, at the same time, it is also shown that the water content of the skin surface decreases as the age group increases, indicating that the skin becomes rough.

[Table 2]

[0026] Therefore, the present invention skin resistance measuring device measured using, by calculating Show R _s it is possible to detect the dryness of his skin, immediately humectant if dangerous It is considered that roughening of the skin can be prevented by application or the like. Specifically, V _i in the face or the hands of a certain point immediately after the highest bathing example skin moisture content 1 day
Measured and compared with the values of R _s numerical may be stored in the device as a reference value of, obtained by measuring the V _i at daytime timely same portion R _s obtained by calculating a, accustomed to dangerous levels Additional functions such as issuing an alarm may be incorporated in the apparatus of the present invention. The device of the present invention is considered to be highly convenient because it can be formed into a small, lightweight and highly portable shape.

In the embodiment described above, gold and zinc oxide were used as different kinds of conductive minerals forming the positive and negative electrodes of the chemical battery, and these were arranged on the surface of the cylindrical roller and in contact with each other. However, it is clear that the present invention can be applied to other combinations of two types of conductive minerals having different standard monopolar potentials, and can also be applied to a case where the electrode shape is, for example, a flat plate or a sphere. .

In the skin resistance measuring device of the present invention, the switching of the plurality of measuring resistors R by the electronic switch, the measurement of the potential difference, and the storage / calculation can be instantaneously performed by the CPU, and desired data are selectively displayed. Because things come,
There is no fear that the reliability of the calculated value fluctuates due to changes in the physiological activity or contact resistance of the skin during the measurement.

According to the present invention, it is possible to estimate the physiological activity of living skin easily, safely and accurately locally, which is very useful for "skin management". Since the device of the present invention functions as a chemical battery only when it comes into contact with the skin, it can be used stably for a long time without fear of deterioration due to self-discharge or leaching of built-in electrolyticity unlike a commercial chemical battery. Can be. In addition, when a short circuit occurs between the electrodes due to wet water or the like, power generation is automatically stopped immediately, so that anyone can safely use the device without generating a trap such as a burn.

If the apparatus of the present invention is used, the measurement of the water content of the hair and the distribution of the subcutaneous fat can be performed, which can be used for beauty and health.

[0031]

As described above, according to the present invention,
It is considered possible to physically and easily detect the “health degree” of the skin from outside the skin easily and safely. By devising the shape of the skin contact electrode made of different conductive minerals that constitute the positive and negative electrodes of a chemical battery, it is possible to identify the skin bioactivity in minute areas, so that monitoring of local lesions and conversely It is possible to investigate the distribution of intradermal activity in a large area, and to capture changes in bioactivity over time. Furthermore, since it is considered that the device can be applied not only to the skin region but also to the change in the activity of the subcutaneous shallow tissue, there is a possibility that the device can be widely used for examination of a lesion in a living body.

[Brief description of the drawings]

FIG. 1 is a diagram (longitudinal sectional view) showing main components of a skin resistance measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the principle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 2 Conductive cylindrical roller 3 Skin 4 Potential difference measurement resistance 6 Measuring unit 7 Storage / calculation unit 8 Display unit 9 Power supply 10, 11 Conductive wire 12 Electronic switch 13 Housing 14 External switch 100 Measurement circuit 101 Measurement processing means

Claims (4)

[Claims] A skin contact surface is made of a conductive mineral having a different standard monopolar potential, a pair of skin contact electrodes arranged at a fixed distance between the skin contact surfaces, and having a resistance value different from each other. A plurality of resistances for measurement, which detect the voltage between both ends of the pair of skin-contact electrodes, are sequentially switched alternately and applied, and a voltage between both ends obtained from each of the applied measurement resistances, A measurement device for skin resistance, comprising: a measurement processing means for calculating various measurement parameters such as skin resistance. 2. The skin resistance according to claim 1, wherein the conductive mineral constituting at least the skin contact surface of the pair of skin contact electrodes is a combination of an n-type semiconductor and a metal having a higher standard monopolar potential. Measuring device. 3. The measurement parameter is a resistance in the skin,
The skin resistance measuring device according to claim 1, wherein at least one of skin contact resistance, skin leakage resistance, intracutaneous current value, and intracutaneous loss voltage is used. 4. A pair of skin-contact electrodes, each of which has a skin-contact surface formed by a conductive mineral having a different standard monopolar potential, is fixed at a fixed interval and simultaneously skin-contacted between said pair of skin-contact electrodes. the potential difference measuring resistor R which is ohmic junction to R _1,
A first process of storing voltage values V ₁ , V ₂ , V ₃ ,... Measured when each of them is sequentially switched and sequentially switched to R ₂ , R ₃ ,. The negative voltage) is E, the electromotive voltage generated by the chemical battery formed on the skin of the living body, R _{d is the} intracutaneous resistance that gives an internal loss of the chemical battery, and R _s is the skin leakage resistance between the pair of skin contact electrodes. _{V i = R i (R s} + R c) E / (R s + R c) (R d + R c + R i) + (R d + R c when the skin contact resistance sum of the pair of skin contact electrodes and R _c ) selection R _i, here solves the i = 1, 2, 3 ... made multiple simultaneous equations R _s, and a second step of calculating the specifications such as R _d, R _s, the specifications, such as R _d And a method of measuring skin resistance, the method comprising: