KR100963874B1 - Special electrode to compensate error caused by thickness fluctuations at skin impeadence measurement - Google Patents

Abstract

The present invention relates to a special electrode capable of compensating for errors caused by fluctuations in the thickness of the outermost layer when measuring skin impedance by measuring skin impedance, and more specifically, a voltage drop trend on the skin surface. By using array electrodes, arrays of voltage measurement electrodes in the direction of current progression are used to detect changes in the pattern of voltage drop according to the thickness change of the outermost layer of the skin, thereby changing the thickness value of the outermost layer. The present invention relates to an electrode that enables error correction by.

The present invention, MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; An electrode portion comprising a plurality of electrodes for detecting a voltage from these electrodes and emitting a current signal received from the voltage-current converter; An effective value-to-DC converter for converting the effective value of the signal detected from the array electrode to DC; A computer for receiving, displaying and simultaneously storing a DC value from the effective value-DC converter through a data collection board, wherein the electrode unit comprises an array electrode having a form of 3 × 8 rows. Electrodes of all columns of the array electrodes are voltage electrodes for detecting voltage, and electrodes of electrode arrays 2 and 7 of the array electrodes are current electrodes for injecting current while being the voltage electrodes.

Skin impedance, electrode, skin moisture level, array electrode, current, voltage

Description

Special electrode to compensate error caused by thickness fluctuations at skin impeadence measurement}

The present invention relates to a special electrode capable of compensating for errors caused by fluctuations in the thickness of the outermost layer when measuring skin impedance by measuring skin impedance, and more specifically, a voltage drop trend on the skin surface. By using array electrodes, arrays of voltage measurement electrodes in the direction of current progression are used to detect changes in the pattern of voltage drop according to the thickness change of the outermost layer of the skin, thereby changing the thickness value of the outermost layer. The present invention relates to an electrode that enables error correction by.

The condition of the skin is closely related to the moisture level of the stratum corneum, so it is very important to measure the moisture level of the stratum corneum.

Many studies have used the impedance method to measure the moisture level in the stratum corneum. However, Organ G. et al. Said that when measuring the impedance of an object, electrodes with narrow intervals as thin as the thickness of the object to be measured should be used. Recently, MEMS processes have been used for this purpose. The MEMS process has many advantages in manufacturing cost, sensitivity, etc. once it enters the mass production system, but mass production of nanoscale materials is not common at present.

Therefore, the skin moisture measurement method using a conventional impedance (impedance) was used for electrodes of several mm intervals, which is a problem that the spread of the current spreads down the stratum corneum layer as the distance between the electrodes is far, It means that the moisture level of the stratum corneum of the skin causes an error in the measured value.

In some studies, using energy in the low frequency band below 1 kHz, even if the electrodes are made wider at intervals of about 3 mm, the percentage of tissue that is not the stratum corneum contributes to the measured impedance value is less than 10%. However, the impedance component of the glass layer and the subcutaneous fat layer under the stratum corneum is significantly lower than that of the stratum corneum, so even if the effect is about 10%, the effect on the total resistance component is greater.

Therefore, in order to implement a system having better performance while using electrodes having a few mm interval, an electrode capable of correcting an error due to variation in thickness value of the outermost layer during skin impedance measurement is desired.

In general, in order to measure the skin impedance, the current is injected into the object and drawn out to the other side. At this time, the impedance of the object is measured using the voltage difference generated on the skin surface.

 However, the current does not selectively pass only the desired portion, but spreads out in the form of diffusion, so it is necessary to obtain information of the unwanted portion.

Therefore, a special electrode capable of correcting this is desired, and it is also desirable to characterize the pattern of data measured using this special electrode.

The conventional skin impedance measurement method simply measures the voltage difference due to current injection and emission, and thus the voltage measurement part consists of only two parts, such as an active electrode part and a common electrode part.

Accordingly, the present invention provides a special electrode in which a plurality of voltage measuring electrodes are arranged in a current traveling direction to observe a voltage drop trend on the surface.

The special electrode of the present invention consists of a total of eight rows of electrode rows, of which the rows 2 and 7 are electrodes for injecting current, and all the electrodes from rows 1 to 8 are electrodes for measuring voltage. 2 and 7 are electrodes for measuring voltage values simultaneously with current injection. Analyzing the measured data using the special electrode of the present invention, it can be seen that the change in the pattern of the voltage drop according to the thickness change of the outermost layer of the skin.

The problem to be solved by the present invention is to provide a special electrode capable of error correction due to the variation in the thickness value of the outermost layer when measuring skin impedance.

Another problem to be solved by the present invention is to change the thickness of the outermost layer of the skin by arranging a plurality of voltage measuring electrodes in the direction of current progress, using an array electrode (Array Electrdoe) to observe the voltage drop trend on the skin surface According to the present invention, there is provided a special electrode that can correct errors in skin impedance measurement, which can detect a change in a pattern of voltage drop.

Another problem to be solved by the present invention is to characterize the pattern of the data measured by using a special electrode that can correct the error due to the variation in the thickness value of the outermost layer during skin impedance measurement to use the data for error correction, etc. To provide.

Another problem to be solved by the present invention is a special electrode consisting of a total of eight rows of electrodes, of these two rows of electrodes, columns 2 and 7 are the electrodes to inject a current, all the electrodes from 1 to 8 columns The electrodes measure voltages, and the second and seventh columns provide a special electrode capable of error correction when measuring skin impedance, which is an electrode that measures voltage value simultaneously with current injection.

Another problem to be solved by the present invention, the voltage drop in order to further apply the voltage drop trend (SR) factor to the impedance value in order to make a more accurate measurement when measuring the skin moisture using the skin impedance It is to provide a special electrode that can derive the trend of.

According to one embodiment of the present invention for achieving the above object, an array electrode, in an array electrode consisting of a plurality of rows and a plurality of columns,

Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage,

An electrode comprising at least one column of the array electrodes may be the voltage electrode and a current electrode for injecting current.

The current electrode is characterized in that the second column from the start column of the array electrode, and the second column from the end column of the array electrode.

And a second row from the end row of the array electrodes as a reference point (ground).

The array electrode is characterized in that the electrode for measuring skin impedance.

The array electrode is characterized in that the electrode for measuring the skin moisture.

According to another embodiment of the present invention for achieving the above object, in an array electrode of the form of 3 × 8 columns, the electrodes of all the columns of the array electrode is a voltage electrode for detecting a voltage, of the array electrodes The electrode of the second electrode row and the seventh electrode row is characterized in that the voltage electrode and the current electrode for injecting current.

The electrode array No. 7 of the array electrode is characterized in that the reference point (ground).

The array electrode is characterized in that the electrode for measuring skin impedance.

The array electrode is characterized in that the electrode for measuring the skin moisture.

The spacing between the electrode and the electrode in the array electrode is characterized in that about 0.5mm.

The electrode of the array is characterized in that the area of 0.8mm.

The array electrode is characterized in that it is made to sample in a linear direction starting from the electrode for the current injection and voltage detection.

The array electrode is characterized in that the spring is mounted.

According to another embodiment of the present invention for achieving the above object, a skin impedance measurement system, MCU for generating a DDS control signal; DDS for receiving the DDS control signal from the MCU to generate a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sinusoidal wave) received from the DDS into a current signal; an electrode consisting of a plurality of rows and a plurality of columns of electrodes, and all of these (multiple rows and a plurality of columns) of electrodes An array electrode capable of detecting a voltage from the plurality of electrodes, the array electrode emitting a current signal received from a voltage-to-current converter with a current electrode composed of at least one of the columns; an effective value for converting an effective value of a signal detected from the array electrode to DC A data acquisition board receiving a DC value received from the effective value-DC converter; It comprises a; computer for displaying data and stored at the same time.

According to another embodiment of the present invention for achieving the above object, a skin impedance measurement system, MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; An electrode portion comprising a plurality of electrodes for detecting a voltage from these electrodes and emitting a current signal received from the voltage-current converter; An effective value-to-DC converter for converting the effective value of the signal detected from the array electrode to DC; A skin impedance measurement system comprising: a computer for receiving, displaying and simultaneously storing a DC value from the effective value-to-DC converter through a data collection board,

The electrode unit includes an array electrode having a form of 3 × 8 rows,

Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage,

The electrode of the second electrode array and the seventh electrode array of the array electrode is characterized in that the voltage electrode and the current electrode for injecting current.

According to another embodiment of the present invention for achieving the above object, a skin moisture measurement system, MCU for generating a DDS control signal; DDS for receiving the DDS control signal from the MCU to generate a sine wave accordingly A voltage-to-current converter for converting a voltage signal (a voltage signal having a sinusoidal wave) received from the DDS into a current signal; consisting of a plurality of rows and a plurality of columns of electrodes, and all of them (a plurality of rows and a plurality of columns) An array electrode capable of detecting a voltage from the electrodes, the array electrode emitting a current signal received from the voltage-to-current converter with a current electrode composed of at least one of the columns; converting an effective value of the signal detected from the array electrode to DC An effective value-DC converter; a data collection board receiving a DC value received from the effective value-DC converter; It comprises a; displaying an emitter, and a computer to store at the same time.

According to another embodiment of the present invention for achieving the above object, the skin moisture measurement system, MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; An electrode portion comprising a plurality of electrodes for detecting a voltage from these electrodes and emitting a current signal received from the voltage-current converter; An effective value-to-DC converter for converting the effective value of the signal detected from the array electrode to DC; And a computer that receives, displays, and simultaneously stores the DC value from the RMS-to-DC converter through a data acquisition board.

The electrode unit includes an array electrode having a form of 3 × 8 columns, and electrodes of all columns of the array electrode are voltage electrodes for detecting voltage, and electrodes of electrode arrays 2 and 7 of the array electrodes are the voltage electrodes. Characterized in that the current electrode for injecting current.

In the skin impedance measurement system, further comprising a power supply for supplying power to the skin impedance measurement system, the power supply is characterized in that the secondary insulation.

In the skin moisture measurement system, further comprising a power supply for supplying power to the skin moisture measurement system, characterized in that the power supply is secondary insulated.

In the skin impedance measurement system, the electrode unit further comprises a buffer unit.

In the skin moisture measurement system, the electrode unit further comprises a buffer unit.

In the skin impedance measurement system, the array electrode is characterized in that the means for correction of the error due to the variation in the thickness value of the outermost layer of the skin.

In the skin moisture measurement system, the array electrode is characterized in that the means for correction of the error due to the variation in the thickness value of the outermost layer of the skin.

The skin impedance measuring system is characterized in that the array electrode is composed of 8 node array electrodes.

The skin moisture measurement system is characterized in that the array electrode is composed of 8 node array electrodes (8 node Array Electrode).

The skin impedance measuring system is characterized in that the computer displays the transmitted data by LabView 8.2 and simultaneously saves it as a text file.

The skin moisture measurement system is characterized in that the computer displays the transmitted data by LabView8.2 and simultaneously stores it in a text file.

The skin impedance measuring system is configured to correct an error due to a variation in the thickness value of the outermost layer of the skin by using a trend SR of the voltage drop measured from the array electrode.

The skin moisture content measuring system is configured to correct an error due to variation in thickness value of the outermost layer of the skin by using a trend SR of the voltage drop measured from the array electrode.

The present invention provides a special electrode for error correction due to the variation of the thickness value of the outermost layer during skin impedance measurement, it is possible to measure the skin impedance more precise and accurate by excluding the information of the unwanted portion.

The present invention uses an array electrode (Array Electrdoe) to arrange a plurality of voltage measuring electrodes in the direction of current progress, so that the pattern of the voltage drop in accordance with the thickness change of the outermost layer of the skin can be observed. It provides a special electrode for error correction when measuring skin impedance that can detect a change, and characterizes the pattern of data measured by using a special electrode for error correction due to variation in thickness value of the outermost layer when measuring skin impedance. The data can then be used for error correction and the like.

The present invention is a special electrode consisting of a total of eight rows of electrodes, of these two rows of electrodes, columns 2 and 7 are the electrodes for injecting current, all the electrodes 1 to 8 columns are electrodes for measuring voltage, Columns 2 and 7 provide a special electrode for error correction when measuring skin impedance, which is an electrode that measures voltage value simultaneously with current injection.

The simulation was performed before to design the electrode of the present invention. In the simulation, the spreading of the current in the skin model was performed by varying the thickness of each layer of the skin with various settings using Ansys 12.0 Multiphysics, and the impedance value of the stratum corneum to be measured was changed when the electrode was not narrow enough. Even if the thickness of the stratum corneum was not changed, it was confirmed that the measured value was affected.

The special electrode of the present invention is based on the existing electrode manufacturing method of several mm intervals, the electrodes are arranged in an array (array) form a single precision electrode having a thickness of 8mm and a 5mm interval arranged in 3 × 8 This is a special type of electrode with a total of 24 pins.

In other words, in the present invention, the MEMS process is not used to fabricate the skin moisture measurement electrode, but the conventional electrode process is used, but the structure of the electrode is composed of an array of 8 nodes, and the 8 voltage values measured from the array electrode are measured. The trend was read and used as a new factor.

This new factor refers to the trend of voltage drop in the direction of the current in the skin, which is correlated with the structure of the skin with Ansys 12.0 Multiphysics. Even if it is the same, the thinner the stratum corneum, the thinner the thickness of the lower layer is affected by the highly conductive layer (liquid layer), it can be seen that the measurement results tend to be smaller.

Gradient factor (SR) using a special electrode made of the array electrode of the present invention helps to measure the impedance of only the stratum corneum of the target, in the present invention can obtain a better impedance measurement results in the general electrode manufacturing process have.

Hereinafter, with reference to the accompanying drawings will be described in detail a special electrode capable of error correction by the thickness value variation of the outermost layer when measuring the skin impedance of the present invention, a method, and simulation for electrode design.

First, a simulation for designing the electrode of the present invention will be described.

<Simulation>

In order to conduct an efficient study on the current flow in applying the impedance method to the skin model, a simulation using Ansys 12.0 was performed.

Figure 1 shows the mesh state of the skin model to be used for Ansys simulation.

The model used PLANE230 Element. The PLANE230 is a 2-D, 8-node, current-based electric element. This element has 1 degree of freedom (voltage) at each node. The 8-node element is natural to express the shape of the voltage, as shown in FIG. 2, and is suitable for modeling curved areas.

This element is based on an electric scalar potential formulation and is applicable to the following low frequency electric field analysis.

The essential goal to simulate is the skin as a 3D form and PLANE230 is a 2D element, but the only aspect to be observed is the cross section, and the electrical phenomena for the cross section are the same in the 3D and 2D elements.

3 is an explanatory diagram for explaining a section for the efficiency of Ansys simulation.

When the mesh is sparse, the computational speed for electrochemical analysis is fast but the results are sparse. On the contrary, the finer the mesh, the slower the computational speed, but the finer the results. As a result of repeated experiments, it was found that the main pattern appeared in the center part, and the delicateness of the center top was important. The model was divided into five sections and mesh was performed. Since the physical properties of the skin are different depending on the layers, as shown in Figure 3, the first three types of 1, 2, 3, and the upper and middle parts of the center to perform a more delicate mesh again 1-2, 2-2 Divided.

FIG. 4 illustrates voltage distribution generated in a model when a constant current is applied to the model illustrated in FIG. 3.

The current injection node coincides with the point marked MX (MAX) because the highest voltage appears, and the current discharge node coincides with the point marked MN (MIN) because the lowest voltage appears. In FIG. 4, the isoline lines are expressed in 48 steps, and it can be seen that a sudden voltage drop (rapid change of color) occurs near the current electrode.

5 shows a simulation result of a skin model in which the thickness of the skin stratum corneum is set to 10 μm, and FIG. 6 shows a simulation result of a skin model in which the thickness of the skin stratum corneum is set to 20 μm.

5 and 6 are graphs of the result of scanning the voltage on the surface, and the graphs of FIGS. 5 and 6 show the difference in the thickness of the stratum corneum with the same physical properties of each layer of the skin. This is the result of graphing the voltage drop of. The target to be measured is the impedance value of the stratum corneum of the skin. Even if the skin model has the same physical properties, the measured voltage value was observed as a result of changing the thickness value of the stratum corneum. When the thickness of the stratum corneum was changed from 10um to 20um, the measured voltage value changed from 6.291V to 6.532V.

If the conventional skin impedance method is used, only the magnitude (Magnitude), which is the difference between the MAX value and the MIN value, is measured. In the above example, since the values are different from each other, if the conventional method is used, the impedance value of the target is different. There is no choice but to. However, it was recognized that there was a problem with these conclusions, and it was recognized that a method of acquiring information on the variation of skin thickness at the same time as measuring skin impedance value was needed.

As a result of many simulations, it can be seen that the voltage drop pattern on the measurement surface changes as the thickness of the object changes.

7 is an example of a skin model in which the skin thickness is adjusted.

The thicker the stratum corneum, the sharper the slope of the voltage drop in the central portion. On the other hand, the thinner the stratum corneum, the sharper the voltage drop phenomenon around the current injection electrode, but the voltage drop near the center between the current electrode was found to be flat because almost no.

If it is assumed that the stratum corneum is very thick and infinitely thick, it can be assumed that the skin is composed of one resistance component (see FIG. 8).

8 is an explanatory diagram for explaining a surface drop pattern analysis in a medium composed of a single impedance component.

In this case, there is a tendency for a uniform voltage drop from the current inlet point to the discharge point.

9 is an explanatory diagram for explaining a surface drop pattern analysis in a medium composed of different impedance components.

As shown in FIG. 9, the skin tends to have a lower resistive component toward the lower layer, and thus will not show a voltage drop pattern in a uniform medium.

The reason why such a phenomenon occurs is that the current has a property of flowing in search of a low resistance component. Under these conditions, the path with the lowest resistivity that the current can take is the way to approach the glass layer as quickly as possible from the moment it touches the surface, then easily reach the point of current discharge through the skin with the low resistivity glass layer and out of the skin. will be. At this time, the voltage drop is made large by the Ohm's law because only a large resistance component must pass while passing through the stratum corneum, and the slope is low because it does not generate a large voltage drop while passing through the glass layer.

In addition, it should be noted in FIG. 9 that the total voltage value generated by the constant current source is also lowered due to the lower slope in the center portion. Analysis of these simulation results shows that there is a correlation between the slope value and the error of the resulting voltage value.

In order to check whether such a phenomenon occurs in a real environment, a specific object is selected, a constant current is injected into the object, the voltage drop pattern is measured, the skin tissue of the animal is obtained, the thickness of the stratum corneum is observed, and the skin tissue and voltage drop are observed. Animal experiments were needed to confirm the correlation between patterns. It was thought that the factors obtained in this way can be proposed in one way to solve the problems of the existing equipment. In addition, a special type of electrode was needed to fabricate impedance measurement hardware to perform animal experiments and to measure a desired voltage drop pattern. In order to measure the voltage drop pattern of the desired skin surface, it was necessary to arrange the electrodes on the surface of the object so as to measure how the voltage changes in the longitudinal direction.

Next, a description will be given of a special electrode capable of error correction due to variation in the thickness value of the outermost layer of the present invention.

<Electrode>

Based on the results of the FEA simulation, a special electrode was designed to observe the voltage drop on the surface even in the experimental environment. The conventional two-terminal electrode measures only magnitude, so it is impossible to measure the trend of voltage drop on the surface. Therefore, it is necessary to design an electrode that can show a kind of effect of voltage sampling in a linear direction starting from the current injection and discharge electrodes on the surface. A special array electrode is proposed as an electrode capable of such sampling effect.

10 is an explanatory diagram for explaining the structure of a special electrode capable of error correction during skin impedance measurement according to an embodiment of the present invention.

Electrodes 2 and 7 are used as current electrodes, and voltage is measured at all electrodes from columns 1 to 8. Electrodes 2 and 7 are both current electrodes and voltage electrodes.

One electrode column is divided into a total of three electrodes in order to improve adhesion to the surface of the object, and constituted a total of eight rows of electrodes. That is, it became the form of 3x8 rows. The seventh electrode row is the reference point (ground).

Dimensions of the electrodes are shown in Table 1.

The numbers in the column of electrodes, the number of electrode blades, the number of electrode gaps, the number of each electrode, etc. in FIG. 10 and Table 1 are not intended to limit the present invention thereby, and are provided to aid the understanding of the present invention. It is noted that various changes can be made within the scope of the present invention.

11 is an explanatory diagram for explaining the structure and appearance of a special electrode for error correction when measuring skin impedance according to an embodiment of the present invention, Figure 12 is for error correction when measuring the skin impedance of FIG. It is sectional drawing of a special electrode. Fig. 12A is a cross sectional view of the special electrode of the present invention as seen from the vane, and Fig. 12B is a cross sectional view of the special electrode of the present invention.

11 and 12, the special electrode of the present invention is an array electrode having a plurality of rows and a plurality of columns. The tip portion of each electrode of the array electrode is cylindrical.

In the housing of the special electrode of this invention, the spring is provided in the adjacent part of an electrode tip part. In general, the pressure applied by the measurer in measuring skin impedance may affect the measured impedance value. To alleviate this, each of the 24 electrodes was equipped with a fine spring. This has the effect of adapting well to surface irregularities or tilting of the electrode.

13 shows an example of a special electrode for error correction when measuring skin impedance of the present invention.

It can be seen that there is almost no pressure applied by the operator in the tilted state as well as in the normal state.

<Measurement system>

There are two main ways to apply energy to measure the impedance of an object. First, the constant voltage method is very simple in circuit design because most power supplies have a constant voltage. However, if the impedance value of the target is unexpectedly lowered, there is a risk that it may cause overcurrent as indicated by Ohm's law. On the other hand, since the constant current method is a method of fixing the current value, the current value is constant regardless of the impedance value of the target, so as to protect the living body that originally blocked the possibility of overcurrent flowing into the living body unless a problem occurs in the system. It is a safe way to do it.

14 is a block diagram of a system configuration of the present invention, a power supply unit 100, a microcontroller unit (MCU) 210, a direct digital synthesizer (DDS) 230, a voltage to current converting (250), The buffer / electrode unit 300, a true RMS-to-DC converter 270, a data acquisition (DAQ) board 400, a computer 450, and the like.

The power supply unit 100 not only supplies power to the system but also uses current in the living body, and thus, the power supply unit 100 implements secondary insulation.

The MCU 210 controls the overall operation of the system and allows the DDS 230 chip to be programmed to easily implement multi-frequency sine waves. That is, the MCU 210 outputs a DDS control signal to the DDS 230.

The DDS 230 generates a sine wave according to the DDS control signal from the MCU 210 and transmits it to the voltage to current converting 260.

The voltage-to-current converter 250 converts a voltage signal (a voltage signal having a sinusoidal wave) received from the DDS 230 into a current and transmits it to the buffer and the electrode 300. The voltage-current converter 250 may perform a sine wave received from the DDS 230 to perform voltage-to-current conversion using a Howland Current Source and a NIC circuit. The DDS 230 may use an AD9851BRS chip.

The buffer / electrode unit 300 is composed of a buffer unit and an array electrode (that is, a special electrode for error correction due to variation in the thickness value of the outermost layer of the present invention).

The buffer unit buffers a current transmitted to each electrode of the array electrode or buffers a signal detected by each electrode. The buffer part consists of a plurality of buffers.

The array electrode is a special electrode for error correction caused by the variation in the thickness value of the outermost layer of the present invention, and the electrodes are composed of a plurality of rows and a plurality of columns. The array electrode may be composed of eight node array electrodes. The array electrode transmits the constant current received from the voltage-to-current converter 250 through the buffer unit to the subject's skin through an 8 node array electrode, and receives voltage values from all 8 nodes.

At this time, the obtained value is in the form of a sine wave, and there are two methods to know the magnitude of the value. The first method is to perform sampling of a proper frequency, and the second is a RMS converting method.

Sampling at the proper frequency requires an additional sampling ADC in the MCU and proceeds to processing the sampled data in all subsequent processing. If the purpose of taking into account the phase detection of the sinusoidal wave is a method of sampling the appropriate frequency is advantageous.

RMS converting method converts sinusoidal wave into DC value in analog circuit, which is convenient in all subsequent processes, and this method is good in case of needing Magnitude of measured sinusoid.

In the present invention, both of the above two methods can be used, and in the present invention, since only the Magnitude of the measured sine wave is required, the RMS converting method is applied.

The RMS-to-DC converter 270 converts the RMS value of the signal detected from the buffer / electrode unit 300 to DC, and the DC value thus obtained is transmitted to the data collection board 400.

The data collection board 400 transmits the DC value received from the RMS-to-DC converter 270 to the computer 450.

Computer 450 displays and simultaneously stores the transmitted data. For example, computer 450 may display the transmitted data by LabView 8.2 and simultaneously save it as a text file.

15 is an example of an isolation power supply and a system according to an embodiment of the present invention.

The photo on the left of FIG. 15 is the isolation power supply, and the photo on the right of FIG. 15 is the system.

FIG. 16A is an example of a screen displayed on the computer of FIG. 14 by measuring a thick stratum corneum, and FIG. 16B is an example of a screen displayed on the computer of FIG. 14 by measuring a thin stratum corneum.

In FIGS. 16A and 16B, when the computer 450 displays the received data by LabView 8.2, the LabView 8.2 Display / Store screen is configured to display two pieces of information. First, the left screen has the X axis as the time axis and the Y axis as the Magnitude axis. The system of the present invention is a multi-frequency system, by changing the frequency by 200Hz at intervals of 2 seconds to 10 times to a total of 300Hz ~ 2.1kHz.

In general, if the frequency is increased when measuring impedance in a living body, the capacitive reactance of the capacitor is lowered, and the magnitude is lowered. In the left pane, you can observe the magnitude of each node's magnitude drop over time.

The grid shown on the right sets the X axis to the node axis (ie, the skin surface distance) and the Y axis to the Magnitude axis. In this graph, we can intuitively guess the SR, which suggests that it correlates with the skin condition of the subject being measured in real time. In FIG. 16A showing the measurement result of the thick stratum corneum, SR can be seen to be somewhat high, and in FIG. 16B showing the thin stratum corneum, the SR is shown to be low.

As described above, in the present invention, the MEMS process is not used to fabricate the skin moisture measurement electrode, but the conventional electrode process is used, but the structure of the electrode is configured as an array of 8 nodes, and the 8 voltages measured from the array electrode are used. The trend of values was read and used as a new factor.

This new factor refers to the trend of voltage drop in the direction of the current in the skin, which is correlated with the structure of the skin with Ansys 12.0 Multiphysics. Even if it is the same, the thinner the stratum corneum was thinner the higher the conductivity of the underlying layer (glass layer) was affected by the measurement results tended to be smaller.

Gradient factor (SR) using a special electrode made of the array electrode of the present invention helps to measure the impedance of only the stratum corneum of the target, it is possible to obtain a better impedance measurement results in the general electrode manufacturing process.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art to which the present invention pertains, various modifications and variations are possible.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

Figure 1 shows the mesh state of the skin model to be used for Ansys simulation.

2 is an explanatory diagram for explaining a node of the PLANE230.

3 is an explanatory diagram for explaining a section for the efficiency of Ansys simulation.

FIG. 4 illustrates voltage distribution generated in a model when a constant current is applied to the model illustrated in FIG. 3.

5 shows simulation results of a skin model in which the thickness of the stratum corneum is set to 10 μm.

6 shows simulation results of a skin model in which the thickness of the stratum corneum is set to 20 μm.

7 is an example of a skin model in which the skin thickness is adjusted.

8 is an explanatory diagram for explaining a surface drop pattern analysis in a medium composed of a single impedance component.

9 is an explanatory diagram for explaining a surface drop pattern analysis in a medium composed of different impedance components.

10 is an explanatory diagram for explaining the structure of a special electrode for error correction when measuring skin impedance according to an embodiment of the present invention.

11 is a cross-sectional view of a special electrode for error correction when measuring skin impedance according to an embodiment of the present invention.

FIG. 12 is a cross-sectional view of a special electrode for error correction when measuring skin impedance of FIG. 11.

13 shows an example of a special electrode for error correction when measuring skin impedance of the present invention.

14 is a block diagram of a system configuration of the present invention.

15 is an example of an isolation power supply and a system according to an embodiment of the present invention.

16A illustrates an example of a screen displayed by the computer of FIG. 14 by measuring a thick stratum corneum.

16B is an example of a screen displayed by the computer of FIG. 14 by measuring a thin stratum corneum.

<Explanation of symbols for the main parts of the drawings>

100: power supply 210: MCU

230: DDS 250: voltage-to-current converter

270: effective value-DC converter 300: buffer / electrode

400: Data Acquisition (DAQ) Board 450: Computer

Claims (29)

In an array electrode consisting of a plurality of rows and a plurality of columns, Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage, And at least one column of the array electrodes is a voltage electrode and a current electrode for injecting current. The method of claim 1, The current electrode A second row from a starting row of the array electrodes, And a second row from an end row of the array electrodes. The method of claim 2, And a second row from the end row of the array electrodes as a reference point (ground). The method according to any one of claims 1 to 3, The array electrode is an array electrode, characterized in that the electrode for measuring skin impedance. The method according to any one of claims 1 to 3, The array electrode is an array electrode, characterized in that the electrode for measuring the skin moisture. In the array electrode of the form of 3x8 rows, Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage, And the electrode of the electrode array No. 2 and the electrode array No. 7 of the array electrodes are current electrodes for injecting current while being the voltage electrodes. The method of claim 6, An array electrode, characterized in that the electrode array No. 7 of the array electrode is a reference point (ground). The method according to any one of claims 6 to 7, The array electrode is an array electrode, characterized in that the electrode for measuring skin impedance. The method according to any one of claims 6 to 7, The array electrode is an array electrode, characterized in that the electrode for measuring the skin moisture. The method according to any one of claims 1, 2, 3, 6 or 7, And an interval between the electrode and the electrode in the array electrode is 0.5 mm. The method according to any one of claims 1, 2, 3, 6 or 7, And an area of 0.8 square millimeters of the electrode in the array electrode. The method according to any one of claims 1, 2, 3, 6 or 7, The array electrode, characterized in that the array electrode is configured to sample in a linear direction from the electrode for the current injection and voltage detection. The method according to any one of claims 1, 2, 3, 6 or 7, And the spring is mounted to the array electrode. MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; Consisting of electrodes in multiple rows and columns, capable of detecting voltage from all of these electrodes (multiple rows and columns), and from a voltage-to-current converter to a current electrode of at least one of An array electrode for emitting a received current signal; An effective value-to-DC converter for converting the effective value of the signal detected from the array electrode to DC; A data acquisition board receiving a DC value received from the RMS-DC converter; A computer for displaying and simultaneously storing data received from the data collection board; Skin impedance measurement system comprising a. MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; An electrode unit comprising a plurality of electrodes for detecting a voltage from the electrodes and emitting a current signal received from a voltage-to-current converter; An effective value-to-DC converter for converting the effective value of the signal detected from the electrode part into DC; A skin impedance measurement system comprising: a computer for receiving, displaying and simultaneously storing a DC value from the effective value-to-DC converter through a data collection board, The electrode unit includes an array electrode having a form of 3 × 8 rows, Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage, Skin impedance measuring system, characterized in that the electrode of the second electrode array and the seventh electrode array of the array electrode is the voltage electrode and the current electrode for injecting current. MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; Consisting of electrodes in multiple rows and columns, capable of detecting voltage from all of these electrodes (multiple rows and columns), and from a voltage-to-current converter to a current electrode of at least one of An array electrode for emitting a received current signal; An effective value-to-DC converter for converting the effective value of the signal detected from the array electrode to DC; A data acquisition board receiving a DC value received from the RMS-DC converter; A computer for displaying and simultaneously storing data received from the data collection board; Skin moisture measurement system comprising a. MCU for generating a DDS control signal; A DDS receiving the DDS control signal from the MCU and generating a sine wave accordingly; A voltage-to-current converter for converting a voltage signal (a voltage signal having a sine wave) received from the DDS into a current signal; An electrode unit comprising a plurality of electrodes for detecting a voltage from the electrodes and emitting a current signal received from a voltage-to-current converter; An effective value-to-DC converter for converting the effective value of the signal detected from the electrode part into DC; In the skin moisture measurement system consisting of; Computer that receives, displays and simultaneously stores the DC value from the effective value-DC converter through a data collection board, The electrode unit includes an array electrode having a form of 3 × 8 rows, Electrodes in all columns of the array electrodes are voltage electrodes for detecting voltage, Skin moisture measurement system, characterized in that the electrode of the electrode array No. 2 and 7 of the array electrode is a current electrode for injecting a current while the voltage electrode. The method according to any one of claims 14 to 15, Further comprising a power supply for supplying power to the skin impedance measurement system, And said power supply unit is secondary insulated. The method according to any one of claims 16 to 17, Further comprising a power supply for supplying power to the skin moisture measurement system, Skin power measurement system, characterized in that the power supply is second insulated. The method of claim 15, The electrode unit further comprises a buffer unit, characterized in that the skin impedance measurement system. The method of claim 17, The electrode unit further comprises a buffer unit skin moisture measurement system, characterized in that. The method according to any one of claims 14 to 15, The array electrode is a skin impedance measurement system, characterized in that for the correction of the error caused by the thickness value variation of the outermost layer of the skin. The method according to any one of claims 16 to 17, The array electrode is a skin moisture measurement system, characterized in that for the correction of the error due to the thickness value variation of the outermost layer of the skin. The method according to any one of claims 14 to 15, The array electrode is a skin impedance measurement system, characterized in that consisting of 8 node array electrodes (8 node Array Electrode). The method according to any one of claims 16 to 17, The array electrode is a skin moisture measurement system, characterized in that consisting of 8 node array electrodes (8 node Array Electrode). The method according to any one of claims 14 to 15, Said computer displays the transmitted data by LabView8.2 and simultaneously stores it as a text file. The method according to any one of claims 16 to 17, Said computer displays the transmitted data by LabView8.2 and simultaneously stores it as a text file. The method according to any one of claims 14 to 15, Skin impedance measurement system, characterized in that for correcting the error caused by the variation in the thickness value of the outermost layer of the skin using the trend of the voltage drop (SR) measured from the array electrode. The method according to any one of claims 16 to 17, Skin moisture level measurement system, using the voltage drop trend (SR) measured from the array electrode, to correct the error due to the variation in the thickness value of the outermost layer of the skin.

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