JP2002085363A - Adipometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adipometer capable of measuring the internal impedance of a subject while accurately determining the condition of the subject himself and the measuring condition of the subject by making it possible to accurately measure at the same time the internal impedance and the impedance of contact between the skin surface of the body and the contact portion of a measuring surface. SOLUTION: The internal impedance is measured with a measuring plate comprising a plurality of contact portions for making contact with the skin surface of the body, and electrically conducting resin plates 1 located between the contact portions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a body fat meter for measuring body fat mass and body fat percentage by measuring impedance in the body.

[0002]

2. Description of the Related Art Conventionally, as this kind of body fat scale, for example, as disclosed in Japanese Patent Publication No. 5-49050,
2. Description of the Related Art There is a known type in which a plurality of electrodes are provided on a measurement plate, and both feet of a subject are placed on the electrodes to measure body fat mass. In such a body fat meter, electrical insulation between the electrodes is a condition for performing a correct measurement. The reason for this is that the conventional body impedance measurement method uses a four-terminal method that can measure only the body impedance to be measured by avoiding the contact impedance between the measurement electrode and the subject ( (Kelvin double bridge method).

Next, a measuring method using the conventional apparatus will be described with reference to FIG. As shown in the figure, in the four-terminal method, for example, electrodes E11 and E12 and electrodes E21 and E22 that are in contact with the skin at two places on the soles of both feet are provided, respectively, and the electrodes E12 and E22 are used as power supply electrodes and the constant current I Is applied, and the voltage signal generated between the electrodes E11 and E21 is measured by a voltage measurement circuit including the AMP11 using the electrodes E11 and E21 as voltage measurement electrodes.

Here, electrodes E11, E12, E21, E
22 and the contact impedance between
1, r12, r21, and r22, and the input impedance of the voltage measurement circuit is set to a sufficiently large value as compared with their contact impedances.
When a constant current flows between the two, the contact impedance r11,
The current that affects the measurement accuracy is substantially prevented from flowing toward r21. In other words, the current I is not split into the contact impedances r11 and r21, but flows through the loop including the in-body impedance r0. To In this way, since the potential drop at the contact impedances r11 and r21 can be ignored, the electrodes E11 and E21
By measuring the voltage between the points, the voltage generated between points P and Q in the body of the subject can be measured.

Since the voltage (potential drop) between the points P and Q is the voltage V11 across the body impedance r0, the voltage V11 is measured and the equation V11 / I
= R0, the in-body impedance r0 can be obtained. That is, the electrodes E11 and E21 function as electrodes capable of measuring only the in-body impedance r0 without being affected by the contact impedance.

By the way, in the measuring method as described above,
As shown in FIG. 16A, if the electrodes E11 and E1
Assuming that there are resistance components R1 and R2 having values that cannot be ignored compared to the magnitudes of the contact impedances r11 and r21 between the electrodes 2 and the electrodes E21 and E22, the currents are r11, r12, R1 and r21, r22, Flows through the loop consisting of R2, the contact impedance r11, r
21 will cause a potential drop.

In this case, the voltage measuring circuit cannot measure the generated voltage of the impedance r0 in the body, which is the voltage between the points P and Q, and the voltage between the points R and S to which the voltage drop of the contact impedances r11 and r21 is added. As a result, the accurate value of the impedance r0 in the body cannot be obtained.

Further, as shown in FIG. 16 (b), if there is a resistance component R3 between the electrodes E12 and E22 which cannot be ignored compared to the impedance r0 in the body,
Since the current i having a magnitude not negligible as compared with the current I flows toward the resistor R3, a large measurement error occurs when the impedance r0 in the body is obtained by the equation r0 = V1 · I.

For these reasons, in the conventional method, the operation of the electrodes is divided into an electrode for applying power and a measuring electrode for measuring voltage, and a constant current (or constant voltage) is applied to the electrode for applying power. By maintaining the insulation between the power supply electrode and the measurement electrode as much as possible, only the accurate body voltage or body impedance is detected and measured from the voltage measurement electrode.

[0010]

However, in the above-mentioned conventional measuring method, particularly when the body fat is measured by placing the foot on the electrode, water or dirt often adheres to the foot. When the measurer performs the measurement, there is a problem that the insulation state between the electrodes is reduced, the electric conductivity is increased, and the above-described measurement error occurs. It should be noted that this type of measuring instrument (particularly, a measuring instrument that functions as both a weight scale and a body fat scale) is often placed in a humid environment such as a bathroom, and it can be said that such a measurement error is highly likely to occur. .

By the way, in the body fat measuring device using the above-mentioned conventional measuring method, the hands and feet of the measurer are wet, the skin surface impedance is lowered, and the measurement error caused by the current flowing on the skin surface is reduced. In fact, no consideration has been given to a function for avoiding the influence and performing a correct measurement, and no consideration has been given to a function for issuing an alarm when such a measurement error occurs.

Note that, in FIG.
2. If the contact state of the measurer with E22 is inappropriate, the load of the constant current circuit increases, the output voltage is saturated, the constant current characteristic cannot be maintained, and a correct measurement value cannot be obtained. However, a device that measures the output voltage of a constant current circuit before such a situation and issues an alarm when the voltage is equal to or higher than a certain value has already been proposed. However, in the case of such a device, the measurement signal source impedance seen from the input terminal of the voltage measurement circuit becomes extremely high as the contact state becomes inappropriate, so that the device is affected by the noise signal from the inductive noise source. And an unpredictable output appears in the output of the voltage measurement circuit. As a result, the measurer may not only mistake the output from the measured value, but also may not be able to make a correct determination as a measurement failure. Further, in this conventional device, no consideration is given to a function of warning which contact portion has a poor contact.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in such a manner that the impedance inside the body and the contact impedance between the electrode and the skin surface of the body can be measured at the same time. It is another object of the present invention to provide a body fat meter capable of accurately measuring impedance in a body while accurately determining a measurement state of a measurer. It is another object of the present invention to provide a body fat meter that allows a measurer to easily determine the location and extent of a problem in the measurement state from various viewpoints.

[0014]

Means for Solving the Problems and Action / Effect To achieve the above object, a body fat meter according to a first aspect of the present invention is a body fat meter for measuring impedance in a body, wherein a contact portion for making contact with a skin surface of a body is provided. A plurality of contact portions including a conductive material.

According to the present invention, since a plurality of contact portions including a contact portion that makes contact with the body skin surface are made of a conductive material, the contact portions that make contact with the body skin surface and the contact portions between the contact portions always remain. An appropriate and measurable current will flow. Therefore, a voltage drop occurs in the contact portions, but a current flows between all the contact portions and between the contact portions, so that the in-body impedance and the contact impedance can be accurately measured. In addition, it is possible to accurately warn of a defective state of the measuring plate having the contact portion or a defective measurement state of the measurer. Furthermore, even if there is moisture adhesion between the contact portions, and the conventional measurement method increases the electrical conductivity between the contact portions so as to cause an error,
By performing the measurement and the calculation in consideration of the equivalent resistance value between the contact portions, it is possible to accurately measure the impedance in the body without lowering the accuracy. Further, since there is no need to provide a special metal electrode, the structure of the measuring plate can be simplified as compared with the conventional one, so that there is an advantage that manufacture is easy.

In the present invention, it is preferable that the mounting table for measuring body fat and the mounting table for measuring body weight are also used so that weight can be measured (second invention). In particular, this body fat meter with a weight scale has a body weight measurement surface that is configured in common with a body fat measurement surface, and is often installed in a bathroom or the like and has many opportunities for moisture to adhere to the measurement surface. Even if it adheres, the impedance in the body can be measured accurately without lowering the accuracy as described above. When the measurement accuracy is affected, an accurate measurement failure alarm can be output.

Next, the body fat meter according to the third aspect of the present invention maintains the impedance in the body and the body skin surface so as to always maintain a measurable electrical conductivity between the contact portions that come into contact with the body skin surface. And the contact impedance of the contact portion of the body fat meter, each of which is independently determined, the determination result of the magnitude of the contact impedance of each part, and the magnitude of the equivalent impedance of each part of the equivalent impedance between each contact. A display means for displaying the determination result is provided.

In the third aspect of the present invention, the result of the determination of the contact impedance is that the contact impedance is measured, and the measured value is too large than a preset reference value, and the measurement is inappropriate. ,
It is preferable that the determination result indicating the degree is displayed by characters, numerals, voices, and the like (a fourth invention). By doing so, even if the measurer takes any contact state with the contact part, the body impedance and the contact impedance are measured without being affected by the induced noise, and the part and the degree of the contact impedance are determined. As a result, an accurate measurement failure alarm can be issued.

The result of the determination of the contact impedance means that the contact impedance is measured, and the measured value is too small than a preset reference value, which means that the measurement is inappropriate, and that the location and the degree of the measurement are inappropriate. It is preferable that the determination result to be performed is displayed by characters, numbers, voices, and the like (fifth invention). In this way, when the measurer affects the measurement accuracy due to the wet skin surface, the operator can judge the part and the extent of the contact impedance including the internal tissue of the skin near the contact part to obtain an accurate measurement failure alarm. Can be issued.

Further, in the third aspect of the present invention, the determination result of the equivalent impedance measures the impedance between the contact portions, and the measurement is inappropriate because the measured value is too small than a predetermined reference value. In addition, it is preferable that the judgment result indicating the position, the position, and the degree be displayed by characters, numbers, voices, and the like (sixth invention). By doing so, it is possible to judge a poor state of the measuring table as in a case where the contact portions are abnormally wet with moisture, and to issue an alarm to the measurer including the position and the degree.

In the third aspect of the invention, it is preferable that the operation of measuring the impedance between the contact portions and the operation of adjusting the zero point when there is no weight load are performed by the same command operation (the seventh invention). . Thus, the measurement operation can be simplified and the burden on the measurer can be reduced.

In the third aspect of the present invention, at least five contact portions between the body skin surface and the conductive measuring plate are provided, and the amount of mental sweating of the measurer is measured from the change in the contact impedance of these contact portions. (8th invention). By doing so, the impedance of many contact portions can be measured at once, and therefore, for example, a minute sweating phenomenon at the fingertip can be accurately detected.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of the body fat meter according to the present invention will be described with reference to the drawings.

FIG. 1 is an equivalent resistance circuit diagram (a) of a body fat meter according to one embodiment of the present invention, and a side view (b) of a conductive plate, and FIG. 2 flows between contact portions at the time of measurement. It is a figure which shows a mode of an electric current.

The present embodiment relates to a measuring instrument capable of measuring body weight together with body fat mass and rate by measuring impedance between both feet. In the present embodiment, a thin conductive resin plate 1 is used for a measurement table on which both feet are placed. In this conductive resin plate 1, the position where the foot is placed on the surface is indicated by a pattern, and the sole of the resin plate 1 where the sole of the foot contacts the resin plate 1 best is electrically connected to a measuring circuit. Terminals E1 and E for exchanging signals
2, E3, and E4 are attached to a total of four places, two places on one foot. Further, these terminals E1 to E4 and the measurement circuit are connected by electric wires.

Since the terminals E1 to E4 of each contact portion are mutually conductive, the terminals E1 to E2, the terminals E2 to E3,
Between terminals E3 and E4, between terminals E1 and E3, terminals E2 and E4
And the equivalent resistance value between the terminals E1 to E4 is r1,
r2, r3, r4, r5, r6. In addition, M is the impedance in the body of the measurer, and X, Y, and X are the contact impedances at two points where the left foot contacts the resin plate 1.
Similarly, assuming that the contact impedance of the two portions of the right foot in contact with the resin plate 1 is Z and U, respectively, at the time of measurement in a state where the constant current circuit for flowing the constant current I is connected to the terminals p1 and p4, The state of the current flowing between the terminals through conductors inside and outside the body is as shown in FIG. Here, since the thickness of the conductive resin plate 1 is small, the impedance value in the thickness direction is small.
The impedance in the thickness direction between the surface and the terminal is included in the contact impedances X, Y, Z, and U. In addition, these impedances include the impedance of the body tissue around the contact portion.

As described above, in the present embodiment, at the time of measurement, a current is applied to all the contact portions by providing conductivity between the contact portions. Therefore, unlike the conventional measuring method, the function performed by each electrode is essentially different, such as a current applying electrode for flowing a current and a voltage measuring electrode for not flowing a current.

By the way, the conductivity between the terminals is not always constant, and the conductivity of the resin plate 1 changes depending on the measurement environment, for example, if moisture adheres. The equivalent resistance value between the contact portions will change. Therefore, in the present embodiment, a function is provided in which the inter-terminal resistance values r1 to r6 are measured and stored in advance before the measurer is placed on the measurement table. When the measuring device also serves as a body weight measurement as in the present embodiment, the inter-terminal resistance values r1 to r6 can be obtained by the same command at the same timing as the zero point measurement of the balance for accurately measuring the weight. It is efficient and convenient.

FIG. 3 shows a state of a current flowing between the terminals p1 and p2 when a constant current circuit having a current value I is connected to the terminals p1 and p2 when the measurer is not on the measuring table. ing. In FIG. 3, the power supply circuit and the voltage measurement circuit are omitted.

As is apparent from FIG. 3, first, the terminal p1
When a constant current I flows between the terminal p2 and the terminal p2, the following equation holds between the voltage between the respective terminals and the current flowing through the terminal-to-terminal equivalent resistance. Between p1 and p2: r1 · i1 = V11 (1) Between p3 and p2: r2 · (i2 + i3) = V12 (2) Between p4 and p3: r3 · i3 = V13 (3) p1−p3 Between: r4 · i2 = V11−V12 (4) Between p4 and p2: r5 · {I− (i1 + i2 + i3)} = V12 + V13 (5) Between p1 and p4: r6 · {I− (i1 + i2)} = V11-V12-V13 (6)

Next, as shown in FIG. 4, the connection points of the constant current circuit are changed to terminals p1 and p3,
When a constant current I flows between 1 and the terminal p3, the following relationship holds between the voltage between the respective terminals and the current flowing through the equivalent resistance between the terminals. Between p1 and p2: r1 · j1 = V21 (7) Between p2 and p3: r2 · (j1−j3) = V22 (8) Between p4 and p3: r3 · {I− (j1 + j2) + j3} = V23 (9) Between p1 and p3: r4 · j2 = V21 + V22 (10) Between p2 and p4: r5 · j3 = V22-V23 (11) Between p1 and p4: r6 · ｛I− (j1 + j2) )｝ = V21 + V22−V23 (12)

As described above, prior to the measurement, when the measurer gives an adjustment instruction from the outside in a state where the measurer is not placed on the resin plate 1 of the measuring table, two types of terminals (p1-p2, p1-p) are provided.
3) is connected to a constant current circuit to perform voltage measurement, and the voltages V11, V12, and V1 shown in Expressions (1) to (12) are obtained.
3, V21, V22, and V23 are obtained.

In these equations (1) to (12), from (1) / (7), i1 / j1 = V11 / V21 = a (13) From (2) / (8), (i2 + i3) / (j1) −j3) = V12 / V22 = b (14) From (3) / (9), i3 / {I− (j1 + j2) + j3} = V13 / V23 = c (15) (4) / (10) From i2 / j2 = (V11−V12) / (V21 + V22) = d (16) (5) / (11) From {I− (i1 + i2 + i3)} / j3 = (V12 + V13) / (V22−V2 3) = e (17) From (6) / (12), {I- (i1 + i2)} / {I- (j1 + j2)} = (V11-V12-V13) / (V21 + V22-V23) = f (18) Here, a, b, c, d, e, and f are divisions of the measured voltage value. Since it is a result, it is a known numerical value.

From Expression (13), i1 = a · j1 (19) From Expression (14), i2 + i3 = b · (j1-j3) (20) From Expression (15), i3 = c · ｛I− ( j1 + j2) + j3｝ (21) From Expression (16), i2 = d · j2 (22) From Expression (17) I− (i1 + i2 + i3) = e · j3 (23) From Expression (18), I− (I1 + i2) = f ｛{I- (j1 + j2)} (24)

By substituting equations (22) and (21) into equation (20), i2 + i3 = d · j2 + c · {I− (j1 + j2) + j3} = b · j1−b · j3 Therefore, (b + c) · j1 + ( (cd) · j2- (b + c) · j3 = c · I (25) By substituting equations (19) and (20) into equation (23), I− (i1 + i2 + i3) = I−a · j1 −b · (j1−j3) = e · j3 Therefore, (a + b) · j1 + (e−b) · j3 = I (26) By substituting equations (19) and (22) into equation (24), , I- (i1 + i2) = I-a.j1-d.j2 = f.If-j.1-f.j2 Therefore, (af) .j1 + (df) .j2 = (1-f)・ I (27) Thus, from equations (25), (26) and (27), j
1, j2, j3 can be represented by the product of a known numerical value of a to f and a known constant current value I. Where j
1, j2, j3 are set as j1 = k1 · Ij2 = k2 · Ij3 = k3 · I, and these values are substituted into equations (7) to (12) to obtain equivalent resistance values r1 to r6. Can be obtained.

It is appropriate that the above-described measurement operation is performed immediately before the measurer measures his or her own body fat and body weight. Therefore, a measurement preparation button is provided separately from the measurement button for measuring the body fat and the command is issued. If the measurer presses the zero-adjustment button, which is also used as the zero-adjustment button normally attached to the weight scale, the zero-adjustment and the above-described equivalent resistance measurement between terminals are performed at the same time. This is convenient because the operation of the measurement work can be saved.

By the way, in order to carry out the above-described measuring method, it is necessary that the electric conductivity between the contact portions is always a certain value or more. For example, if the terminals E1 to E4 are basically kept in an insulated state as in the related art, j1, j2, j3 may be obtained under an environment condition where the measurement surface is normally dry.
Is an extremely small value, and measurement cannot be performed with high accuracy. Therefore, in the measurement method of the present embodiment, even if the measurement surface has an environmental change from a dry state to a moist state, the contact portions are always kept at an appropriate electrical conductivity at all times, and the terminals are in contact with each other. It is a necessary and sufficient condition to measure the impedance in the body without deteriorating the accuracy so that the equivalent resistance value between the parts changes within a measurable range.

When the obtained equivalent resistance value between the terminals is abnormally low, it is considered that the contact portions, that is, the body contact portions of the conductive plate of the measuring table are abnormally wet with moisture. If the measurement surface is abnormally wet as described above, the body skin is also wet, so that an increase in current flowing on the body surface makes it impossible to accurately measure the impedance in the body. Therefore, a certain lower limit is provided for the values of the equivalent resistance values r1 to r6, and if any of these equivalent resistance values becomes lower than the set lower limit, if the value of the measurement table is poor, each of the values is regarded as poor. It is preferable that a warning is given to the measurer including a corresponding part and the degree of the state failure by a display or a sound.

Next, as described above, the electrical conductivity between the contact portions is determined in the form of an equivalent resistance value, and those values are stored in a memory. After that, the measurer places his or her foot on the electrode. The operation of measuring the impedance in the body when an instruction to start measuring the amount of body fat is given will be described. Here, the measurement start may be instructed by the measurer himself with a key switch, or when the measuring device is also used for weight measurement, the measurement is automatically started by detecting a certain weight value or more. You may do it.

As shown in FIG. 2, first, a constant current circuit (not shown) for supplying a current value I between terminals p1 and p4.
Connect. As a result, the current is applied to all the terminals through the equivalent resistance of the resin plate 1, in other words, the current is applied to the body impedance and all the contact impedances present for each terminal, and the potential drop occurs at each portion. Occurs. On the other hand, the voltage between all terminals is measured by a voltage measuring circuit (not shown).

A circuit equation represented by the following equation is established in the body, the contact portion, and the resin plate (conductive plate). Between p1 and p2: X · {I− (i1 + i2 + i3)} + Y · {I− (i1 + i2 + i3 + i4)} = V1 (28) Between p3 and p4: −Z · {I− (i1 + i2 + i4 + i6)} + U · (i4 −i5) = V3− (V1 + V2) (29) Between p1 and p4: X · {I− (i1 + i2 + i3)} + M · i4 + U · (i4-i5) = V3 (30)

A relational expression expressed by the following equation holds between each equivalent resistance and the current. Between p1 and p2: r1 · i3 = V1 (31) Between p1 and p4: r6 · i1 = V3 (32) Between p1 and p3: r4 · i2 = V1 + V2 (33) Between p2 and p4: r5 · i6 = V3-V1 (34) Between p2 and p3: r2 · {I− (i1 + i2 + i4 + i6)} = V2 (35) Between p3 and p4: r3 · {I− (i1 + i4 + i6) + i5} = V3- (V1 + V2) (36) Here, I is a known constant current value, and since r1 to r6 are all known by prior measurement, the equations (31) to (36) are used.
Thus, all the current values i1 to i6 can be obtained.

Next, as shown in FIG. 5, a constant current circuit for supplying a current value I is connected between the terminals p2 and p4.
At this time, a circuit equation represented by the following equation is established at the contact portion. Between p1 and p2: X · j4-Y · j2 = −V4 (37) Between p3 and p4: −Z · j6 + U · (j2 + j4-j6) = V6−V5 (38)

A relational expression expressed by the following equation is established between each equivalent resistance and the current. Between p2 and p3: r2 · j3 = V5 (39) Between p3 and p4: r3 · (j3 + j5 + j6) = V6−V5 (40) Between p1 and p3: r4 · j5 = V5−V4 (41) ) Between p2 and p4: r5 · j1 = V6 (42) Between p1 and p2: r1 ｛{I− (j1 + j2 + j3)} = V4 (43) Between p1 and p4: r6 · ｛I− (j1 + j2 + j3 + j4 + j5) ｝ = V6−V4 (44) Thus, all the current values of j1 to j6 can be obtained from the equations (39) to (44).

The circuit equations (28), (29) and (30)
(37) By solving (38), the contact impedances X, Y, Z, U and the body impedance M become i1
I6 and j1 to j6. Here, i1 to i6 can be represented by r1 to r6 and V1, V2, V3, and j1 to j6 are r1 to r6 and V
4, V5, V6, r1 to r6
Is known in the measurement preparation mode and stored in the memory, so that the values of the impedances X, Y, Z, U, and M can be obtained when the measurement voltages V1 to V6 are obtained. Further, the values of the body fat mass and the body fat percentage can be obtained in the same manner as the conventional body fat meter using the value of the impedance M in the body.

If water adheres to the resin plate (conductive plate) 1 and the conductivity between the contact portions changes, each time,
By executing the step of measuring the resistance between terminals of the contact part,
The values of the inter-terminal resistance values r1 to r6 at each time can be obtained. Therefore, if the body fat measurement step is performed after measuring the inter-terminal resistance values r1 to r6 in advance by the measurement preparation command, it is possible to avoid an error in the process of calculating the impedance M in the body.

According to the measuring method of the present embodiment, the measuring input terminal of the voltage measuring circuit does not have a high resistance regardless of the contact state of the measurer with the contact portion. For example, in the circuit of FIG. 2, since a constant current circuit is connected between the terminals p1 and p4, the impedance between the input terminal and the terminal of the voltage measurement circuit when connected to the voltage measurement circuit at the same time becomes Even in the maximum case (when the measurer is separated from the contact portion), it is a combined resistance value determined by the inter-terminal resistance values r1 to r6, and the impedance seen from the input terminal of this voltage measurement circuit is always a low value. Become. Therefore, unlike the conventional measurement method, the situation where the contact state deteriorates, the signal source impedance at the input terminal becomes extremely high, and erroneous measurement due to the addition of inductive noise does not occur. Thus, since the voltage between the terminals p1 to p4 can always be accurately measured, the contact impedances X, Y, Z, U and the impedance M in the body can be accurately obtained without being affected by noise.

However, between the terminals p1-p2, the terminals p2-p
3 and the voltage between the terminals p3 and p4 are close to the values equivalent to the case where the measurer is not in contact with the contact portion, the contact impedances X, Y, and
Large values are obtained as the values of Z and U. In such a state, since the inflow current into the body is insufficient and the accurate impedance M in the body cannot be obtained, the values of the contact impedances X, Y, Z, and U become larger than a certain value. In this case, it is preferable to output a warning as a contact failure together with a position corresponding to the contact impedance.

When the values of the contact impedances X, Y, Z, and U are large and small, even if the value of the impedance M in the body changes by the same amount, the inter-terminal resistance values r1 to r6
The amount of change in the current flowing to is different. If the amount of change in the current is small, the terminals p1 and p2, the terminals p2 and p3, the terminal p
The amount of change in voltage between 3-p4 is also small. If the amount of voltage change is too small, accurate measurement cannot be performed because the sensitivity of the measurement circuit (resolution of the A / D converter) has an upper limit. As described above, the measurement limit at which the impedance M in the body can be measured with a predetermined accuracy can be determined by design in view of the resolution of the A / D converter. Accordingly, the contact impedances X, Y, Z, and U are correspondingly determined. Can be determined by design. In this way, the alarm of the measurement limit can be accurately transmitted based on the limit determined from the design viewpoint without depending on the contact state of the measurer.

On the contrary, the contact impedances X, Y, Z,
By utilizing the fact that the value of U is too small, it is also possible to warn of a problem in using the body fat scale. For example, in a finger-measurement-type body fat meter that measures body impedance using two fingers of both hands, contact impedance X,
The values of Y, Z, and U include not only the contact impedance between the skin surface of the fingertip and the electrode or conductive plate, but also the impedance from the skin surface to the base of each finger. When dry, it exhibits an impedance of several hundred ohms. However, when measured in the wet state of the hand, the current flowing on the skin surface of the fingertip increases, and the contact impedance X,
The values of Y, Z, and U become extremely small. In this case, not only does the impedance of the contact portion between the skin surface and the electrode portion decrease, but also the bifurcation points P and Q in the measurement of the tissue of the two right and left fingers in FIG. 2 move toward the fingertip. That is, the impedance M in the body increases accordingly, and a problem arises in that the measured value of the impedance in the body is different even for the same individual.

Therefore, in the case of such a finger-measurement-type body fat meter, a lower limit value in consideration of a fingertip impedance value in a standard dry state is set for each type of finger if necessary. In addition, the contact impedances X, Y,
By comparing the values of Z and U with the respective lower limits,
If any of the values of Y, Z, and U is lower than the lower limit, it is determined that measurement that maintains the accuracy cannot be performed, and an alarm is given to the measurer along with words and characters indicating an inappropriate part. Here, the standard value may be obtained by averaging a plurality of normal measurement values for each individual.

As described above, the upper limit values Xu, Yu, Zu, Uu and the lower limit values Xl, Yl, Zl, Ul for maintaining accurate measurement are set in the measuring device in advance for each contact portion. When the measurement results of the contact impedances X, Y, Z, and U satisfy the following formulas, it is determined that the measurement is normal. Emits. Xl <X <Xu Yl <Y <Yu Zl <Z <Zu Ul <U <Uu

If the equivalent resistance values r1 to r6 are too small, a sufficient current may not flow toward the impedance in the body to maintain the measurement accuracy. In this case, the measurement is performed as described above. Judgment is made based on the measurement result of the preparation command. That is, a minimum reference value rl suitable for measurement is set, and when r1 to r6> rl, it is determined that measurement is suitable,
If any one of the equivalent resistance values does not satisfy this inequality, an alarm is issued as measurement inappropriate.

In addition, since the equivalent resistance value of the measurement surface and the impedance value in the vicinity of the contact portion of the measurer can be quantified in this way, it is possible to measure the degree of unsuitability with respect to an inappropriate or abnormal value. It is also possible to show the improvement condition of the measurement condition to the measurer in an easy-to-understand manner.

For example, the current value of the measurement surface equivalent resistance r1 is represented by r1.
When r1> r1p, the measurement is inappropriate if r1> r1p. However, the deviation r1e = r1p−r1 is further compared with a set value rd prepared in advance, and if r1e <rd, it is extremely inappropriate.
If d <r1e <rl, it is considered slightly unsuitable, and if the contents of the meaning indicating the unsuitable stage corresponding to the display are displayed together with words and characters indicating the parts of r1, r2... It can be a convenient index.

The same applies to such a display mode for the above-mentioned display of the wet state of the fingertip. That is,
Evaluating the magnitude of the difference between the current measured value and the lower limit, the display with a gradual meaning of slightly unsuitable, very unsuitable, etc., along with words and letters indicating the part, will be measured. It is convenient for a person to manage and judge his / her skin condition when using the measuring instrument.

[0057]

Next, a specific embodiment of the body fat meter according to the present invention will be described.

FIG. 6 shows the weight / weight according to one embodiment of the present invention.
A plan view (a) of the body fat meter and a cross-sectional view (b) thereof along the line AA are shown.

In the weight / body fat meter 2 of the present embodiment,
As shown in FIG. 6 (a), the display 3 is arranged at the front, and the measuring plate 4 on which the measurer places his / her feet is arranged at the rear.
Is arranged. Here, the display 3 is provided with key switches for displaying measured values such as weight, body fat mass, body fat percentage and the like, and setting values such as age, gender, etc., and for inputting setting data and instructing various operations. ing. Also, measuring plate 4
On the upper side, a picture 5 indicating a position where the front part and the rear part of the soles of both feet are brought into contact with each other is drawn. FIG. 6 (b)
As shown in FIG. 2, a measuring instrument cover 7 is provided on the lower surface of the measuring plate 4 via an insulating sheet 6 and terminals 8 are arranged. Each terminal 8 is connected to a lead wire 9 leading to a measuring circuit. I have.

In this embodiment, the measuring plate 4 is a conductor, and is made of a conductive resin or the like. If the measuring instrument cover 7 is made of resin, the insulating sheet 6 can be omitted. In this case, the measuring surface can be simply formed of a single conductive resin plate. There is also a method in which a thin insulating sheet having a hole in a portion corresponding to the pattern 5 is pasted on the conductivity measuring plate. Further, as a method of attaching a terminal for electrically connecting the measurement plate 4 and the measurement circuit, a method of directly screwing to the back surface of the measurement plate 4, a method of using a screw or a conductive adhesive, a standard foot There are a method of using a terminal based on a thin metal plate having the same size as the contact area, a method of providing a terminal together with a metal film directly sputtered and deposited on a resin, and the like. In addition, since this metal film is formed on the back surface of the resin plate and does not directly touch the measurer, even a thin film does not wear.

FIG. 7 is a block diagram of the weight / body fat meter 2 of the present embodiment, and FIG. 8 is a detailed block diagram of the measurement calculation circuit in FIG.

As shown in FIG. 7, a weight sensor (LC) 11 is supported on the measuring plate 4 via a support fitting 10. In addition, each terminal E1, E2, E3 of the measuring plate 4
The E4, the weight sensor 11, and the display 3 are configured to exchange signals with the measurement operation circuit 12, respectively. Here, it is assumed that the weight sensor 11 is equipped with a strain gauge type load cell in this embodiment.

As shown in FIG. 8, in the measurement operation circuit 12, the contact impedance between the measurement plate 4 and the front and rear skin surfaces of the sole is X, Y, Z, and U, respectively.
And the impedance in the body is M. Also, r
1 to r6 are equivalent resistance values between four terminals attached to the back of the measurement plate 4. Note that the value of the equivalent resistance value changes depending on the surface state of the measurement plate 4.

Each of the terminals E1 to E4 is a terminal p of the circuit.
1, p2, p3, p4, and these terminals p1 to p
Reference numeral 4 denotes an output terminal o1 and an input terminal o of the constant current circuit 13 via analog switches AS3 and AS4 on the internal circuit board.
2 and an analog switch AS
1, AS2, terminals s1, s2 of the voltage measurement circuit 14
You can connect to it. Here, the constant current circuit 1
Reference numeral 3 denotes an operational amplifier AMP1 that receives a voltage signal V0 (known) from a non-inverting input terminal and outputs a constant current I, and a reference resistor Rs that controls a circuit such that the operational amplifier AMP1 outputs a constant current I. (Known), and I =
It is configured to allow a constant current of V0 / Rs to flow into the body and into the accessory resistance. Further, the voltage measurement circuit 14
An operational amplifier AMP2 for outputting a voltage generated between the terminals s1 and s2, and input resistors R1 and R1 of the operational amplifier AMP2.
R2 is provided. Note that these input resistances R
1, 1 and R2 are selected to be large enough so as not to affect the measurement accuracy as compared with the signal source impedance of the measurement signal.

In the measurement operation circuit 12,
A power supply (POW) 15 for exciting the gauge bridge of the load cell LC (gravity sensor 11) and an arithmetic circuit 16 including AMP3 as an amplifier circuit for the load cell signal are provided.

The output signal (AC) from the operational amplifier AMP2 of the voltage measuring circuit 14 is converted into a DC signal by a rectifier circuit (REC) 17 and smoothed by a filter (FIL1) 18. On the other hand, the weight signal output from the AMP3 of the arithmetic circuit 16 is a weight signal filter (FIL).
2) smoothed by 19; An output terminal of each of the filters 18 and 19 has an analog switch AS5.
The A / D converter 20 is connected via the A / D converter 20, and the A / D converter 20 digitizes an analog signal. Further, the output data from the A / D converter 20 is output to the I / O circuit 2
1 and various operations are executed by the CPU 22 based on the data from the I / O circuit 21. Further, the CPU 22 stores RO calculation results, various calculation programs, numerical settings, calculation operations, and the like.
A memory 23 composed of an M / RAM or the like is connected. Further, the I / O circuit 21 has a display (DIS) 3 for displaying data and an operation switch (K) for inputting data.
EY) 24 are connected.

The CPU 22 includes an analog switch AS
The ON / OFF control signals of 1 to AS5 are output through the I / O circuit 21. Here, the analog switch AS5 is
When the impedance is measured, the filter is switched to the filter 18 side, and when the weight value is measured, the filter is switched to the filter 19 side.

Next, the measurement procedure will be described. First,
Prior to the measurement of body weight and body fat, when the measurer presses the measurement preparation button on the measuring instrument, the analog switch AS5 selects the filter 19, and the weight on the measuring plate 4 in the unloaded state is A / D. The digital value of the weight is obtained by inputting to the converter 20. Then, the obtained value is input to the zero weight memory, and the zero adjustment is completed. After this, the analog switch AS
5 is connected to the filter 18 side, and measures the current inter-electrode impedance of the measurement plate 4. This procedure is as described with reference to FIGS.
Thus, the measured values r1 to r6 of the equivalent resistance values between the terminals are stored in the memory 23.

In this embodiment, since the measuring plate 4 is made of a conductive material such as a conductive resin, the resistance between the terminals always has a certain value or less regardless of the surface condition of the measuring plate 4. Therefore, current flows and a potential drop occurs. Thereby, the equivalent resistance value between the terminals can be always measured regardless of the state on the measurement plate 4. If the impedance between the terminals further changes due to adhesion of water or the like, the resistance components due to the water are in parallel with the resistances r1 to r6, and the change in the value can be measured.

Next, when the above-mentioned zero adjustment and the storage of the state on the measuring plate are completed, the measurer performs measurement such that the front part and the rear part of the soles of both feet contact the pattern 5 on the measuring plate 4 respectively. Get on the table. At this time, the weight level is detected and automatically (or by the operator pressing the measurement button)
The analog switch AS5 switches to the filter 19 side again. Thereafter, when the vibration waveform of the weight signal is stabilized, the weight value of the measurer is measured and stored, and at the same time, the analog switch AS5 is again switched to the filter 18 side, and the mode is shifted to the in-body impedance measurement mode. In this case, it is preferable that a signal (display or voice) of “measurement possible” is given to the measurer at the time when the zero point adjustment and the state storage on the measurement plate are completed.

In the body impedance measurement mode, the measurement is performed as described with reference to FIGS. In this way, since the impedance M in the body is obtained using the equivalent resistance value between the terminals according to the state at each time, the impedance value in the body is not affected by external factors as in the related art.

In the present embodiment, the measurement plate is formed of a conductive plate so that a measurable current always flows between the terminals. However, as shown in FIG.
The contact portion with the skin may be constituted by electrodes (metal plates) 8, 8, and these may be fitted into the measurement plate (conductive plate) 4 and attached. Also, as shown in FIG.
By fitting the electrodes (metal plates) 8 and 8 into the insulator plate 6 and connecting the electrodes 8 and 8 with an appropriate value of resistance rn, the electrical conduction between the electrodes is always an appropriate value for the electrodes. The degree may be given.

In this embodiment, the measuring plate is formed in a substantially rectangular shape,
Although a description has been given of a configuration in which appropriate electrical conductivity is provided between all the contact portions, as shown in FIG. 10A, a measurement plate 4 ′ made of a conductive resin is substantially U-shaped in plan view. And between the terminals E1 and E2, between the terminals E2 and E4,
Only between terminals E3 and E4 are equivalent resistance values r1 and r, respectively.
5, r3. FIG. 10B shows an equivalent resistance circuit in this case.

Further, as shown in FIGS. 11 (a) and 11 (b), a metal electrode is formed on each of two separated conductors.
It is also possible to arrange them in pairs so that only between the electrodes E1 and E2 and between the electrodes E3 and E4 have equivalent resistance values r1 and r3, respectively. As an application example of the measuring instrument having such a circuit configuration, as shown in FIG. 11B, there is a body fat meter configured to contact one finger corresponding to each electrode. In the case of such a body fat meter, a sufficient distance is maintained between the set of electrodes E1 and E2 and the set of electrodes E3 and E4 from the electrode arrangement, so that the electric conductivity is extremely small.
The change in electrical conductivity between them does not affect the measurement accuracy. However, since the distance between the electrodes E1 and E2 and the distance between the electrodes E3 and E4, which are adjacent to each other, are extremely short, the electric conductivity easily changes due to environmental changes even if the space between them is made of an insulator. Resulting in. On the other hand, according to the measuring method as in the present embodiment, the electrode E
1 and E2 and between the electrodes E3 and E4 are maintained at an appropriate electric conductivity, and a current flows between the contact portions and the electrodes to cause a potential drop sufficient for measurement. It can be said that the body fat meter is effective to be applied to the measuring method of this embodiment.

In the measuring plate of this embodiment, all of the contact portions have the functions of both current application and voltage measurement at the same time.
When mounting the terminals of each contact part on the back of the measurement plate,
Alternatively, various forms are possible, such as using the contact portion as a metal electrode and disposing the electrode close to the insulating plate. In this case, according to this embodiment, even if the material between the contact portions or between the electrodes is made of a conductor or an insulator, even if the conductivity between adjacent contact portions changes due to an environmental change, compensation is made. The feature is that it can be done.

Further, according to the measuring method of the present embodiment, it is characterized in that the contact impedance of the conductor contact portion or the metal electrode can be obtained independently simultaneously with the impedance in the body.

If the contact impedance is too large, FIG.
, The output of the operational amplifier APM1 for the constant current circuit is saturated and correct measurement cannot be performed. Even before that, if the contact impedance becomes too large, the current applied to the body becomes too small, causing an error. Therefore, as described above, an alarm is issued when any of the contact impedance values becomes too large. More specifically, for example, numbers 1 to 4 are respectively displayed corresponding to the contact portions of the measurement surface shown in FIG. 6A, and the impedance of the contact portion corresponding to the number is equal to or more than a predetermined value. When the value becomes large, the part and the degree are alerted to the measurer by a display or a sound. The measurer can easily know which part has a contact failure by this alarm. If the value of the contact impedance or the stepwise level of the impedance value is displayed, the degree of the contact failure can be easily known. Thus, a highly accurate and reproducible measurement operation can be performed.

On the contrary, considering the impedance of the fingertip tissue, for example, there is a problem even if the contact impedance is too small than a predetermined value. In this case, the range of the tissue measured as the impedance in the body may change. Therefore, in the present embodiment, the measurer is also alerted to the degree and location of the contact impedance that is too small by a display or a sound.

In the above description, during the measurement preparation operation,
Although the description has been given of obtaining the equivalent resistance value between the terminals of the contact portions or the electrodes, the state of the surface of the measuring table can be known from the measured values. Even though the measurement can be performed without error in consideration of the conductive state of the surface of the measurement plate, there is still a limit. If there is too much water, the skin itself gets wet and causes an error. Therefore, similarly to the contact impedance, a boundary value is provided for the equivalent impedance value between the contact portions,
When any one of the equivalent impedance values r1 to r6 is smaller than a predetermined value, it is preferable to display the part and the degree by numerical values, characters, or the like or to issue an alarm by voice.

As described above, according to the present embodiment, it is possible to reliably inform the measurer of the measurement state of the measurer, the quality of the state of the measurement table, and the location. It is possible to grasp the condition of the skin surface of the part and to maintain and manage the surface of the measuring table in a normal state.

According to the measuring method of the present embodiment, since the contact impedance of each finger can be measured simultaneously, a portable (card-type) body fat meter as shown in FIG. Electrode pairs E1, E2 and E
It is preferable to apply the present invention to a body fat meter in which 3, E4 is arranged.

Although the contact impedance changes due to the sweating action of the skin, if the body fat meter shown in FIG.
At the same time, sweating at four places on the skin surface can be measured using only the impedance of the contact portion, which is separated from the impedance in the body, which is convenient for detecting the sweating phenomenon, which is essentially a small change. . Moreover, such measuring instruments must be entertaining and easy to measure,
Being portable and finger-measuring is an important requirement,
Such a configuration is extremely useful.

In the case of the measuring device shown in FIG. 12, since the electrodes are installed on the front and back sides of the measuring device main body, there is little possibility that the electric conductivity between the two electrodes changes due to environmental changes. However, at least as shown in FIG. 11A, a resistor is connected between the electrodes, or the electrodes are made of a material having an appropriate electric conductivity. In this case, it is preferable that the value of the inter-electrode resistance component be known from the time of design, because the prior measurement of electric conductivity can be omitted, and this known value can be used as a constant coefficient for impedance calculation.

Further, as described above, the contact impedance changes due to the sweating action of the skin, and the amount of this change is small, so that the more measurement points, in other words, the more measurement data, the easier the detection and the more accurate the measurement. become. That is, according to the measurement method of the present embodiment, for example, the values of the contact impedances X, Y, Z, and U can be simultaneously collected from, for example, four contact portions, so that the respective changes Δx, Δy, Δ
Even if z and .DELTA.u are small values, and even if they are large and small, by using in the form of an addition value such as .DELTA.x + .DELTA.y + .DELTA.z + .DELTA.u, it is easy to catch a small amount of impedance change, and accurate measurement can be expected. .

FIG. 13A shows a body fat / psychiatric meter in which the number of electrodes is increased to five. In this example, the electrodes E1 and E2 are pressed by two fingers of the right hand and the electrodes E3, E4 and E5 are pressed by three fingers of the left hand during measurement. FIG. 13B is an equivalent circuit diagram of the body fat / psychiatric meter. Note that, in the figure, a power supply circuit and a measurement circuit are omitted. In FIG. 13 (b), M represents the impedance in the body, X and Y represent the combined impedance of the contact portions between the electrodes and the fingers and the finger joints of the two fingers of the right hand, and Z, U, and K represent the left hand. It shows the combined impedance of the contact portions between the electrodes and the fingers and the finger joints for the three fingers.

In this circuit, the same analysis as in the case of four electrodes is possible. For example, a constant current is applied between the terminals p1 and p5 and between the terminals p2 and p3, and the measured voltage of each terminal is measured. From the values of the equivalent resistance values r1, r2, and r3 between the electrodes, six independent circuit equations hold, and the impedances X, Y, Z, U, K, and M can be represented by the measured voltage and the equivalent resistance value between the electrodes. it can. Therefore, in this case, the change in impedance of the five contact portions can be captured.

Similarly, if at least one contact portion is provided between each finger and each electrode, the impedance value of at least 10 contact portions and the amount of change thereof can be detected in body fat and mental sway. Meter can be configured. Further, even when a plurality of electrodes are arranged at one contact portion per finger, more accurate sweat measurement can be expected by detecting from many contact portions.

Of course, the measuring signal detecting section of this measuring instrument is not of the type of pinching with fingers, but gripping both hands grips 25, 25 attached to a portable measuring instrument as shown in FIG. It can also be a method. An equivalent circuit diagram in this case is shown in FIG.

In these systems, in the case of a system in which the electrodes are brought into contact with a plurality of places on the palm, or in the case of a system having a plurality of contact electrodes for the same finger (see FIG. 11), the contact impedance between the electrodes is extremely high. If it is smaller, select a smaller equivalent resistance value r1 or insert a resistor with an appropriate resistance value between the measurement terminal and the electrode by connecting in series with the contact impedance so that the apparent contact impedance is appropriate. It is necessary to increase r1 to a larger value, and to select r1 larger accordingly, so that the current distribution can be balanced.

[Brief description of the drawings]

FIG. 1 is an equivalent resistance circuit diagram of a body fat meter according to an embodiment of the present invention (a), and a side view (b) of a conductive plate.

FIG. 2 is a diagram (1) illustrating a state of a current flowing between contact terminals during measurement.

FIG. 3 is a diagram illustrating a state of a current flowing between respective contact portion terminals when a constant current circuit is connected to terminals p1 and p2 when a measurer is not on the measuring table; .

FIG. 4 is a diagram illustrating a state of a current flowing between the respective contact portion terminals when a constant current circuit is connected to the terminals p1 and p3 when the measurer is not on the measuring table. .

FIG. 5 is a diagram (2) illustrating a state of a current flowing between the contact portion terminals and in the body at the time of measurement.

FIG. 6 is a plan view (a) of a body weight / body fat meter according to one embodiment of the present invention and a sectional view taken along line AA of FIG.

FIG. 7 is a block diagram of a weight / body fat meter according to the present embodiment.

FIG. 8 is a detailed block diagram of a measurement operation circuit in FIG. 7;

FIGS. 9A and 9B are diagrams showing another embodiment of the measuring plate.

FIG. 10 is a plan view (a) and an equivalent circuit diagram (b) showing still another embodiment of the measurement plate.

FIGS. 11A and 11B are diagrams showing another embodiment of the measuring instrument.

FIG. 12 is a diagram showing still another embodiment of the measuring instrument.

FIG. 13 is a diagram (a) showing still another embodiment of the measuring instrument and an equivalent circuit diagram (b) thereof.

FIG. 14 is a diagram (a) showing still another embodiment of the measuring device and an equivalent circuit diagram (b) thereof.

FIG. 15 is an explanatory view (1) of a conventional measuring method.

FIG. 16 is an explanatory view (2) of a conventional measuring method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive resin plate 2 body weight / body fat meter 3 display 4 measuring plate 5 picture 6 insulating sheet 7 measuring instrument cover 8 electrode 9 lead wire 10 support bracket 11 weight sensor 12 measurement arithmetic circuit 13 constant current circuit 14 voltage measurement circuit 15 Power supply 16 Operation circuit 17 Rectifier circuit 18, 19 Filter 20 A / D converter 21 I / O circuit 22 CPU 23 Memory 24 Operation switch AS1-AS5 Analog switch E1-E6 Electrode or terminal

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 1, 2001 (2001.3.1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

A circuit equation represented by the following equation is established in the body, the contact portion, and the resin plate (conductive plate). Between p1 and p2: X ｛{I- (i1 + i2 + i3)} + Y ｛{I- (i1 + i2 + i3 + i4)} = V1 (28) Between p3 and p4: -Z ・i5 + U ・ (i4-i5) = V3- (V1 + V2) (29) Between p1 and p4: X ｛{I- (i1 + i2 + i3)} + M ・ i4 + U ・ (i4-i5) = V3 (30)

Continued on the front page F term (reference) 2G028 AA01 BB10 BC07 CG08 HN00 4C027 AA06 DD03 EE01 EE03 EE05 EE08 FF01 FF02 GG00 HH06 HH11 KK00 KK01 KK03 KK05 KK07

Claims (8)

[Claims] 1. A body fat meter for measuring impedance in a body, wherein a portion between a plurality of contact portions including a contact portion to be brought into contact with a body skin surface is made of a conductive material. 2. The body fat meter according to claim 1, wherein the mounting table for measuring body fat and the mounting table for measuring body weight are also used so that weight can be measured. 3. The impedance in the body and the contact impedance of the contact portion with the body skin surface are maintained so that the contact portions to be brought into contact with the skin surface of the body and the contact portions are always kept at a measurable electrical conductivity. It is a body fat meter to be obtained independently, and a judgment result of the magnitude of each of the parts of the contact impedance,
A body fat meter provided with a display means for displaying the magnitude of the equivalent impedance between each contact portion and the magnitude of the magnitude for each region. 4. The determination result of the contact impedance is:
This contact impedance is measured, and this measurement value is too large than a preset reference value, so that the measurement is inappropriate, and the site, the determination result indicating the degree is displayed by characters, numerals, voices, and the like. The body fat meter according to claim 3, which is a thing. 5. The determination result of the contact impedance is as follows:
This contact impedance is measured, and the measurement result is inappropriate because the measured value is smaller than a preset reference value, and the site, the determination result indicating the degree is displayed by characters, numerals, voice, and the like. The body fat meter according to claim 3, which is a thing. 6. The determination result of the equivalent impedance is:
Measure the impedance between each contact part, determine that the measurement is inappropriate because the measured value is too small than the preset reference value, and determine the location, the determination result indicating the degree, letters, numbers, voice, etc. The body fat meter according to claim 3, wherein the body fat meter is displayed by: 7. The body fat meter according to claim 3, wherein the operation of measuring the impedance between the contact portions and the operation of adjusting the zero point when there is no weight load are performed by the same command operation. 8. The method according to claim 3, wherein at least five contact portions between the body skin surface and the conductive measurement plate are provided, and the amount of mental sweating of the measurer is measured from the change in the contact impedance of these contact portions. Body fat scale.