RU2519955C1 - Sensor for measuring impedance of human body section - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: sensor 1 for measuring impedance of a human body section includes the first and the second electrodes and electrode holder 2. Electrodes consist of sections. Sections 5 and 6 of the first and the second electrodes are located alternately in one row on the inner surface of the holder. The holder is intended to be fixed around human wrists so that sections of both electrodes can touch the wrist. Each electrode has at least three sections. Contact area of each section is at least 1 cm². The electrode holder is made in the form of a flexible strip or a bracelet having sections that are hinged between themselves, which is fixed on the wrist by means of clasp 7, or in the form of a cuff covering the wrist. A signal converter of the sensor is also arranged in the electrode holder.

EFFECT: use of the invention will allow improving stability of a measurement signal and sensitivity of a sensor owing to improving contact reliability of sensors with human skin and optimising a current passage way between sections of sensors.

7 cl, 7 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the field of measurements for diagnostic purposes, in particular to the design of sensors for measuring the impedance or electrical resistance of the human body, and can be used in monitoring systems for human condition.

BACKGROUND

Known designs of sensors for measuring the electrical resistance of a portion of the human body located around the wrist.

So, in the patent RU 2251156 (publication 04/27/2005, IPC АВВ 5/05) a system for monitoring the operator’s health by the level of wakefulness and precursors of hypoglycemia is described. The system proposes to use sensors that include two pairs of electrodes, in particular for measuring the electrical resistance of the skin. The electrodes of the first pair have a galvanic connection with the inner surface of the skin of the wrist or finger, and the electrodes of the second pair with the back of the hand or wrist. The sensor mounting means may be in the form of a glove or part thereof. However, this design does not provide reliable contact of the electrodes with human skin, especially during the movement of the hand, therefore, does not provide sufficient stability of the measuring signal from the sensors and the sensitivity of the sensors.

International application WO 2010/128500 (publication 11.11.2010, IPC AB 5/00) describes a method and system for measuring glucose concentration in human blood by measuring the impedance of a body part and then registering a pulse wave. In one embodiment of the system, sensors are used that are arranged in rows around the wrist on a flexible holder. Each of the sensors is a separate transmitter, which is connected to the measuring system at regular intervals. At each moment in time, one of the sensors is connected to the measuring system. During the movement of the hand, contact with the skin of each of the sensors may be broken. Since the system takes readings sequentially from each sensor, at some point in time the measurements may be interrupted due to the lack of reliable contact of the sensor with the skin.

SUMMARY OF THE INVENTION

The technical problem to which the present invention is directed is to increase the stability of the measuring signal and increase the sensitivity of the sensor for measuring the impedance of a portion of the human body, which is achieved due to a more reliable contact of the sensor electrodes with the skin, including during movement of the hand on which the sensor is attached .

The sensor for measuring the impedance of a portion of the human body, in accordance with the present invention, includes a first and second electrodes and an electrode holder. Both electrodes are made sectional, and the sections of the first and second electrodes are alternately arranged in the same row on the inner surface of the holder. The holder itself is made with the possibility of fixing around the wrist of a person so that sections of both electrodes are adjacent to the wrist.

Achieving the indicated technical result — increasing the stability of the measuring signal and increasing the sensitivity of the sensor — is achieved by increasing the reliability of the contact of the sensors with human skin and optimizing the current path between the sections of the sensors, which is achieved by:

- perform electrodes sectional;

- placing sections of the electrodes on a holder fixed around the wrist;

- the location of the sections of the electrodes alternately in one row on the inner surface of the holder.

Reliability of the contact is ensured by the fact that each electrode is made of several sections, and the electrode holder ensures that they fit snugly against the wrist. Therefore, when moving the arm, at least one of the sections of each of the electrodes will be constantly in contact with the skin. In addition, due to the alternate arrangement of the electrode sections around the wrist, an electric current flows through the tissues of the wrist, in which there is a large blood supply, while the total electric current passes through a sufficiently large volume of blood-filled tissues, which also increases the sensitivity of the sensor.

The number of sections of each electrode may be at least three.

Each section of both electrodes has a contact area of at least 1 cm ² . Due to the fact that the electrodes are sectional and each of the sections has a sufficiently large area of at least 1 cm ² , the stability of the measuring signal and the sensitivity of the sensor are further increased.

In a particular case, the electrode holder can be made in the form of a flexible tape fixed to the wrist with a fastener, for example, Velcro.

In addition, the electrode holder can be made in the form of a bracelet having sections pivotally connected to each other.

The electrode holder can also be made in the form of a tightened wrist cuff.

In addition, the sensor may further comprise a sensor signal converter located in the electrode holder.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by the following graphic materials.

Figure 1 shows a perspective view of an example implementation of the sensor, in which the holder of the electrodes is made in the form of a flexible tape, in accordance with the present invention.

Figure 2 schematically shows the mounting of the sensor on the wrist.

Figure 3 shows the location of the electrode sections on the holder and the electrical connection of the sections of the first and second electrodes of the sensor depicted in figure 1.

Figure 4 shows a view of the cross-section AA shown in Figure 3 of the holder in the region of one of the electrode sections.

Figure 5 shows another example of a holder design with a cavity for accommodating a sensor signal transducer.

Figure 6 shows a diagram of the electrical connection of the sections of the first and second electrodes with the formation of the first and second sensor electrodes.

Figure 7 illustrates the direction of the currents flowing through a portion of the human body between the sections of the electrodes of the sensor made in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The sensor 1 (FIG. 1) for measuring the impedance of a portion of the human body comprises a holder 2 with a first electrode 3 and a second electrode 4 (FIG. 3) mounted on it, which are made of separate sections 5 and 6, respectively. In this example, the holder 2 of the electrodes is made in the form of a flexible tape with a fastener 7 type fastener, which allows you to fix it tightly around the wrist 9, as shown in Fig.2. The holder 2 of the electrodes can be made of plastic and other materials, ensuring the holder is wrapped around the wrist 9. For a specialist it is clear that the holder of the electrodes can have a different design, for example, can be made in the form of a bracelet having sections pivotally connected to each other, or a cuff tightly worn on the wrist (these options are not shown in the drawings).

The electrodes 3 and 4, made in the form of separate sections 5 and 6, respectively, are placed on the inside of the holder 2, so that when putting the sensor 1 on the wrist 9, sections 5 and 6 of the electrodes 3 and 4 are adjacent to the wrist 9. Sections 5 and 6 of both electrodes 3 and 4 are arranged on the holder 2 in a row alternately. That is: section 5 of electrode 3 is followed by section 6 of electrode 4, then again section 5 of electrode 3, followed by section 6 of electrode 4, etc. In Fig.1, Fig.3, Fig.5 - Fig.7 sections 5 of the electrode 3 are marked with the letter "a", and sections 6 of the electrode 4 are marked with the letter "b".

It has been experimentally established that a near-optimal embodiment of the sensor 1 contains four sections 5 and 6 of each electrode 3 and 4. The contact area of each section 5 and 6 is at least 1 cm ² . The shape of the sections 5 and 6 of the electrodes 3 and 4 may be diverse, for example rectangular, as shown in FIG. 1, or round, as shown in FIG. 5. All sections 5 are electrically interconnected, as shown in FIGS. 3 and 6, forming an electrode 3, similarly, all sections 6 are electrically interconnected, forming an electrode 4.

A flexible printed circuit board 8 (FIG. 4 and FIG. 5) or a printed circuit board in the form of sections connected by flexible conductors can be installed inside the holder 2. On the printed circuit board 8, for example, a sensor signal converter and batteries can be placed which serve to power the sensor and convert the sensor signals to digital form and transfer them to an external processing device. The signal processing device can also be located in the holder, and the sensor can be equipped with a monitor and controls.

A sensor 1 for measuring the impedance of a portion of a human body, in this case, a portion of a body of a hand, operates as follows. Thanks to the holder 2, which is fastened around the wrist 9 with a fastener 7, the contact surfaces of the sections 5 and 6 of the electrodes 3 and 4 fit snugly against the skin of the wrist 9. The execution of the electrodes 3 and 4 sectional ensures constant reliable contact of at least two sections 5 and 6 of the electrodes 3 and 4 with skin during any movements of the hand. Due to the fact that the electrodes 3 and 4 are made sectional, and each of the sections 5, 6 has an area of at least 1 cm ² , the total area of each electrode, for example, in the case when it is made of four sections, is at least 4 cm ² , which increases the reliability of the contact of the electrodes 3 and 4 with the skin and the sensitivity of the sensor 1.

The arrangement of sections 5 and 6 alternately (Fig. 7) ensures the passage of electric current 12 (shown by dashed arrows) through the soft tissue 10 of the wrist 9, while the currents from the individual sections 5, 6 are summed. With this arrangement of sections 5 and 6, the current does not pass through the bones 11 of the arm, which have greater electrical resistance than blood-saturated soft tissues 10, which also affects the sensitivity of the sensor in the direction of its increase.

The design of the sensor provides an increase in the sensitivity of the sensor by increasing the reliability of the contact of the sensor electrodes with human skin, increasing the area of the sensors and optimizing the path of the current through the human body between the sections of the sensors. Based on this design, it is possible to create systems that allow continuous monitoring of various parameters of human life.

Claims (7)

1. A sensor for measuring the impedance of a portion of the human body, including the first and second electrodes and the electrode holder, both electrodes are made sectional, and the sections of the first and second electrodes are arranged alternately in one row on the inner surface of the holder, made with the possibility of fixing around the wrist so so that the sections of both electrodes are adjacent to the wrist. 2. The sensor according to claim 1, characterized in that the number of sections of each electrode is at least three sections. 3. The sensor according to claim 1, characterized in that each section of both electrodes has a contact area of at least 1 cm ² . 4. The sensor according to claim 1, characterized in that the electrode holder is made in the form of a flexible tape fixed to the wrist with a fastener. 5. The sensor according to claim 1, characterized in that the electrode holder is made in the form of a bracelet having sections pivotally connected to each other. 6. The sensor according to claim 1, characterized in that the electrode holder is made in the form of a tightened wrist cuff. 7. The sensor according to claim 1, characterized in that it further comprises a sensor signal transducer located in the electrode holder.

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