KR100834542B1 - A vein measurement device - Google Patents

Abstract

The present invention relates to a vein measuring device, which is attached to the pads of the (+) electrode and (-) electrode to the arm of the human body at regular intervals and is installed on the needle in the state of fixing the patch-shaped reference electrode inside the pad By moving the measuring electrode, it is possible to easily find the vein by using the potential difference according to the difference between the fat and vein medium.

In the present invention, after the system is turned on, the calibration is selected in the measurement / calibration selection menu, and the voltage of the first measurement terminal for which the VR voltage is set to 1K ??, respectively, is checked. Next, after checking the voltage of the second measuring terminal, compare the voltage of the first measuring terminal with the voltage of the second measuring terminal, and if the values match, it is possible to know that the system is operating normally. Calibrate the system by adjusting the menu values.Refer to the voltage value table for standard resistors, select all the items in the calibration selection menu, and then select the measurement from the measurement / calibration selection menu and start the measurement. At this time, the measured value of the VR voltage and the value of the VR amplifier are measured and recorded, and the conductivity is calculated from the measured value.

Description

Vein measurement device

1 is a view showing a state in which a four-electrode pad attached to the arm of the human body in accordance with the present invention.

Figure 2 is a block diagram of the vein measuring device of the present invention.

Figure 3 is a circuit diagram showing the structure of the electrode and the voltage regulation circuit and the offset adjustment unit of the present invention.

4 is a circuit diagram for applying a reference voltage of the present invention.

5 is a front view of the measuring device of the present invention.

Figure 6 is a rear view of the measuring device of the present invention.

<Explanation of symbols for main parts of drawing>

1: power supply part 2: electrode part

3: constant current generating unit 4: offset adjusting unit

5: Government Administration 6: Potential Output

40: display means

The present invention relates to a vein measuring device, and in particular, the pads of the (+) and (-) electrodes are attached to the arm of the human body at regular intervals, and the measuring electrodes are fixed little by little while fixing the patch-shaped reference electrodes inside the pads. While moving, it is possible to easily find veins by using the potential difference according to the difference between the fat and vein medium.

In general, blood pressure is high because arteries are the passage of blood from the heart, while blood pressure is relatively low because veins are blood that is sucked back into the heart by the pumping of the heart.

Therefore, when the artery is damaged, blood pressure is spouted out due to blood pressure, but the vein is lowered than the arterial blood pressure, so it is not pumped out, so when the vein is cut by the knife, there is no severe bleeding unless it is deeply cut.

Usually, when injecting or bleeding in the human body, such a vein to find a needle in the vein and put the medicine directly into the blood vessels or blood through the vein.

Conventionally, in the case of finding a vein in the human body and injecting or drawing blood, when a vein protrudes outward in a state in which a certain portion of the arm is tied using a rubber band, a needle is inserted into the vein to inject or draw blood.

Therefore, in the prior art, when finding a vein, the blood is pulled in a state in which the vein protrudes by tying the arm with a rubber band, thereby making it difficult to find a vein with pressure on the human body.

In addition, conventionally, a method of detecting veins using a two-electrode method has been proposed and used. However, in the two-electrode method, it is difficult to maintain a constant reference potential at a corresponding electrode, thereby causing an electric double layer and polarization phenomenon. There was a problem that (polarization) occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve these conventional drawbacks, and an object of the present invention is to attach a plurality of pads having (+) and (-) electrodes at predetermined positions of an arm of a human body, and between the pads a reference electrode. It is to provide a vein measuring device to easily find a vein by using a potential difference appearing according to the difference of the vein of the human body and the skin of the flesh by moving the measuring electrode installed in the needle little by little.

In other words, the present invention uses a four-electrode method to maintain a constant reference potential at the corresponding electrode, thereby minimizing the effects of electric double layer and polarization in the two-electrode method. To provide a possible vein measuring device.

The present invention for achieving the above object is a pair of pads that are attached to the arm of the human body at a predetermined distance, the reference electrode positioned between the pads, while moving little by little between the pads according to the media of the fat and vein And a potential difference display means for indicating a potential difference between the reference electrode and the measurement electrode.

According to the present invention, the potential difference display means combines a power supply unit capable of supplying a constant power supply and being capable of recharging, and a feedback circuit of a constant potential to a potential measurement method similar to the 4-terminal measurement method used in the conductivity measurement method of a solid sample. The potential difference between the potential sensing electrodes is kept constant, the electrode part providing the potential by the voltage follower, the constant current generator consisting of the JFET and the Zener diode to apply a constant voltage, and the input terminal of the operational amplifier to reduce the error value It includes an offset adjustment unit connected to one side, a calibration unit for adjusting the potential between the reference electrode to 0V and correcting the offset voltage in the op amp of the output stage to perform the overall compensation for various errors, and a potential output unit for outputting the potential It is characterized by.

The present invention is characterized in that the electrode unit comprises an operational amplifier and a potential difference regulator.

The present invention is characterized in that the offset adjustment unit is configured to adjust the potential between the reference electrodes to 0V and to compensate for errors by correcting the offset voltage in the operational amplifier of the output terminal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows an embodiment applied to the arm of the human body of the present invention, the (+) pad 16 and the (-) pad 17 is attached to a predetermined position of the arm 15 of the human body and the reference electrode 2A And a view for explaining the process of finding the vein 25 using the measuring electrode 2B, the reference electrode 2A is attached in the form of a patch, the measuring electrode 2B is installed on the needle, the 4 The electrode is configured to be connected to the display means 40 to exhibit a potential difference.

Fig. 2 is a block diagram showing the configuration of the potential difference display means 40 of the present invention, which is similar to the four-terminal measurement method used in the power supply unit 1, which supplies a constant power supply and is capable of recharging, and the conductivity measurement method of a solid sample. By combining the feedback circuit of a constant potential with the potentiometry method, the potential difference between the potential sensing electrodes R is kept constant, and the electrode portion 2 providing a potential by a voltage follower, JFET and A constant current generator 3 consisting of a zener diode to apply a constant voltage, an offset adjuster 4 connected to an input single side of the operational amplifier 8 to reduce the error value, and a potential between the reference electrode and an output terminal And an electric potential output part 6 for outputting electric potential.

3 is a circuit diagram showing the structure of the electrode, the voltage regulating circuit and the offset adjusting unit of the present invention, in which terminals E1 and E2 of both ends of the electrode 10 are connected to the output terminal of the operational amplifier 8, and the electrode 10 The operational amplifiers 7 and 8 are connected via the resistors R1 and R2 at the center, and the potential difference regulator 9 is connected between the operational amplifiers 7 and 8.

In addition, an offset adjusting unit 4 is connected to the input terminal side of the operational amplifier 8, and the offset adjusting unit 4 is composed of resistors R1-R5, variable resistors VR, diodes D1, D2, and the like. It is configured to adjust the potential between the reference electrodes to 0V and to correct the offset voltage at the operational amplifier 8 of the output stage.

Referring to the operation of the present invention configured as described above is as follows.

In general, electrical conductivity is an inverse of electrical resistance, which indicates an easy flow of electric current in a solution, and is applied to various fields with values that vary depending on the increase or decrease of ions or particles.

The present invention is to easily find the vein of the human body by applying such electrical conductivity, the power supply unit 1 in the vein measuring device of the present invention is configured by using a battery of ㅁ 12V can minimize the power supply noise and potential If it is lowered, it can be recharged.

In addition, the reference electrode 2A and the measurement electrode 2B of the electrode portion 2 positioned as shown in FIG. 1 have a constant potential similar to that of the 4-terminal measurement method used in the conductivity measurement method of the solid sample. By combining the feedback circuit, the potential difference between the potential sensing electrodes R is kept constant, and the potential can be measured more stably and accurately by using a voltage follower (vlotage follower).

The constant current generator 3 of the present invention uses a JFET and a zener diode and can apply a constant voltage as a constant current source.

In addition, the present invention calculates a voltage difference between two potential sensing electrode resistors R1 (R2) in the middle while current flows to the electrode through the terminals E1 and E2 across the electrode 10. It is configured using the amplifier (7) (8) and the potentiometer (9), and fed back to the current strength, the strength of this current can be seen through the potential between the reference electrode.

According to the present invention, a calibration is performed first, and then a measurement is performed, and an error of an internal circuit must be adjusted for accurate calibration.

Here, the operational amplifiers 7 and 8 constituting the circuit do not have ideal characteristics, and the error may include an input bias current and an offset voltage.

Since these errors are different for each operational amplifier, the error value varies depending on which operational amplifier is used, which is related to the measurement range of the circuit.

The present invention is a means for reducing the error value, as shown in Figure 3 has an offset adjuster (4) on one side of the input terminal of the operational amplifier (8), each to correct the error of the internal bias current and the offset voltage Instead of adjusting the operational amplifiers 7 and 8, the potential between the reference electrodes is adjusted to 0 V and the offset voltage is corrected in the operational amplifier 8 of the output stage to perform the overall compensation for various errors.

In addition, as shown in Figure 4, the present invention applies a standard resistance between the reference electrode to compensate for the influence on the measurement environment or temperature to correct the measurement error based on the conductivity of the standard resistance standard resistance configured for this Are 0Ω, 10Ω, 100Ω, 1KΩ and 10KΩ, respectively, and connect 1KΩ resistor across the standard resistor.

And a selector switch 20 for selecting the vein measurement and the calibration. When the measurement is selected, the conductivity of the sample connected to the electrode 10 is measured. When the calibration is selected, the standard resistance (for example, 0Ω, 10Ω, 100Ω) is selected. , 1KΩ, 10KΩ) and measure the conductivity.

However, at the time of selecting the VR voltage, a current of 0.1 mA always flows from the constant current generating unit 3, and the VR Volt switch selects a resistor for applying a voltage across the reference electrode 10, 0Ω-. Apply voltage of 0 V, 1 mV, 10 mV, 100 mV, 1V through 10KΩ resistor selection.

Here, a low voltage must be applied for accurate measurement, but the reliability of the measured value due to an error is low.

On the other hand, in the VR amplifier (Amp) selection menu, the VR amplifier is a switch for selecting a resistance to the voltage drop caused by the current flowing through the actual sample, and selects a resistance value similar to the measured sample in general.

In addition, the first measuring terminal / second measuring terminal in Figure 5 is a terminal for connecting a voltmeter, the first measuring terminal is a terminal for measuring the voltage across the reference electrode, the second measuring terminal for measuring the voltage of the measurement sample Terminal, red terminal represent (+), and black terminal represent (-) respectively.

FIG. 6 shows an on / off switch of the power supply unit 1 and a terminal for charging the battery, and connects the +,-, and GND terminals of the power supply unit 1 during charging. Connect GND to the black terminal and (-) to the blue terminal.

Hereinafter, the calibration and measurement method according to the present invention will be described.

With the system power on, power is supplied from the power supply 1, select calibration from the measurement / calibration selection menu of the selector switch 20, and set the VR voltage to 1KΩ.

In this state, the voltage of the first measurement terminal is checked. At this time, the voltage should be about 100 mV, which is normal.

Next, after confirming the voltage of the second measuring terminal and comparing the voltage of the first measuring terminal and the voltage of the second measuring terminal, it can be seen that the system is operating normally.

In addition, the system is calibrated by adjusting the VR voltage value and the value of the VR amplifier calibration selection menu, and then select all the items in the calibration selection menu by referring to the voltage value table for the standard resistor.

Next, the measurement is selected by the selection switch 20, and the measurement is started. At this time, the selected value of the VR voltage and the value of the VR amplifier are measured and recorded.

Based on the measured values, the conductivity is calculated by the following equation (1).

상기 [수학 1]을 통해 계산된 살갗과 정맥의 매질차에 의한 전위차인 전도도는 통상적으로 표시되는 숫자 형태로 디스플레이수단(미도시)에 표시되며, 이를 보면서 정맥의 위치를 찾게 된다.
즉, 인체의 팔의 소정위치에 (+)와 (-)전극을 가진 복수의 패드를 부착하고, 이들 패드사이에 기준전극을 고정시킨 상태에서 주사바늘에 설치된 측정전극을 조금씩 이동시키면 상기 디스플레이수단에 살갗과 정맥의 매질차에 의한 전도도가 표시되는지를 확인하고, 측정전극의 이동을 계속 수행하다 전도도가 표시되면 현재 위치에 정맥이 있는 것으로 판단한다.

Conductivity, which is the potential difference due to the difference in fat and vein media calculated through Equation 1, is displayed on a display means (not shown) in the form of a number that is normally displayed, and looking for the position of the vein.
That is, when the plurality of pads having (+) and (-) electrodes are attached to a predetermined position of the arm of the human body, and the measurement electrodes installed on the needles are moved little by little while the reference electrodes are fixed between the pads, the display means Check if the conductivity is displayed by the difference between the fat and vein medium, and continue to move the measuring electrode. If the conductivity is displayed, it is determined that there is a vein at the current position.

As described above, the present invention adopts the 4-electrode method in the means for measuring the vein of the human body so that the vein of the human body can be easily found in the state of reducing the measurement error due to polarization or contamination of the electrode surface. There is.

In addition, since the present invention is a four-electrode method, there is no influence by the electrode cord between the electrode and the main body, and the effect of power supply noise can be minimized by the power supply unit using the battery as well as the battery can be recharged.

Claims (4)

A pair of pads attached to the arm of the human body at a predetermined distance, a patch-shaped reference electrode positioned between the pads, and a small distance between the pads are moved little by little to the needle to measure the potential difference according to the difference in the media of the flesh and vein. And a potential difference display means for displaying the potential difference between the reference electrode and the measurement electrode. The method according to claim 1, wherein the potential difference display means includes a power supply unit capable of supplying a constant power supply and a rechargeable power supply circuit, and a feedback circuit of a constant potential in a potential measurement method similar to the four-terminal measurement method used in the conductivity measurement method of a solid sample. Coupled to maintain the potential difference between the potential sensing electrodes (R) and providing a potential by a voltage follower, a constant current generator consisting of a JFET and a Zener diode to apply a constant voltage, and calculated to reduce the error value An offset adjuster connected to the input terminal of the amplifier, a calibration unit for adjusting the potential between the reference electrode to 0V and correcting the offset voltage in the operational amplifier of the output stage to compensate for various errors, and a potential output unit for outputting the potential Vein measuring device, characterized in that configured to include. The vein measuring apparatus according to claim 2, wherein the electrode unit comprises a plurality of operational amplifiers and potentiometers. The vein measuring device according to claim 2, wherein the offset adjusting unit is configured to adjust the potential between the reference electrodes to 0V and compensate for the error by correcting the offset voltage in the operational amplifier of the output terminal.

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