HK40102772A - Electrocardiogram measurement apparatus - Google Patents

Description

Electrocardiogram (ECG) measurement equipment

This application is a divisional application of the invention patent with an application date of 2018-12-3, application number 201880077772.1, and title "Electrocardiogram Measurement Device".

Technical Field

This invention provides an easily obtainable electrocardiogram (ECG) containing highly useful information for analyzing a patient's cardiac condition, based on electrical signal waveforms. An ECG consists of an ECG measuring device (measuring sensor) and a computer. In recent years, almost everyone uses a smartphone. A smartphone can be considered a computer with wireless communication and excellent display capabilities. Therefore, the combination of an ECG measuring device (measuring sensor) and a smartphone can provide a good ECG. This invention relates to an ECG measuring device (measuring sensor) that can be used by an individual in conjunction with a smartphone. According to the International Patent Classification (IPC), this invention, as a device for measuring ECGs, is classified as class A61B5/04, which detects, measures, or records bioelectrical signals of the human body.

Background Technology

An electrocardiogram (ECG) is a useful device that can conveniently diagnose a patient's heart condition. ECGs can be categorized into several types depending on their intended use. To obtain as much information as possible, a 12-channel ECG using 10 wet electrodes is used as the standard in hospitals. Patient-sensory devices are used to continuously measure a patient's heart condition using a small number of wet electrodes attached to the patient's body. Holter monitors and event recorders, which are portable and usable by the user, have the following basic functions: a compact, battery-powered storage device for storing measurement data, and a communication device for transmitting data. Holter monitors primarily use 4 to 6 wet electrodes and cables connected to these electrodes, providing a multi-channel ECG. However, a disadvantage of Holter monitors is that the wet electrodes attached to the body via cables can be uncomfortable for the user. Patch-type ECG electrodes also require continuous attachment to the body.

On the other hand, the event recorder is portable, allowing users to measure their ECG promptly when they experience cardiac abnormalities. Therefore, the event recorder is small and primarily lacks cables for connecting electrodes, with dry electrodes on its surface. According to existing technology, the event recorder is a 1-channel electrocardiogram (ECG) that primarily measures an ECG signal by having both hands contact two electrodes respectively.

The electrocardiogram (ECG) measuring device for the purposes of this invention should be user-friendly, provide accurate and comprehensive ECG measurement results, and be compact and portable. For user-friendly operation, the device must be able to transmit data wirelessly with a smartphone. Therefore, the device must be battery-powered. Devices requiring increased battery life and reduced size should not include a display screen, and the ECG should be displayed on the smartphone.

To provide accurate and comprehensive electrocardiogram (ECG) measurements, two limb leads are measured directly in this invention. As described later, in this invention, four leads can be calculated and provided based on the simultaneous measurements of the two limb leads. Generally, in relation to ECG, "channel" and "lead" are used interchangeably to refer to an ECG signal or ECG voltage. The term "simultaneously" should be used very carefully in relation to ECG. The meaning of "simultaneously" is not "sequential." That is, simultaneously measuring two leads actually means measuring two ECG voltages at any given time. Specifically, if Lead I voltage is sampled simultaneously with Lead II during periodic sampling, the time for each sampling of Lead II must be less than the sampling time since Lead I was sampled. Note also the use of the term "measurement." The term "measurement" should only be used when actually measuring a physical quantity. In digital measurements, one measurement should represent one AD conversion. As described later, for example, by measuring Lead I and Lead III in an ECG measurement, Lead II can be calculated according to Kirchhoff's voltage law. In this case, lead II must be stated as "calculated," as stating it as "measured" would cause confusion.

One of the most challenging problems in electrocardiogram (ECG) measurement is eliminating electric line interference (ERI) contained in the ECG signal. A well-known method for eliminating ERI is the driven right leg (DRL) method. In fact, all ECGs use the DRL method to eliminate ERI. A drawback of the DRL method is that one DRL electrode must be attached to the right foot or the lower right part of the torso. Therefore, in order to measure two limb leads using the DRL method, in the prior art, four electrodes, including the DRL electrode, must be in contact with the body. However, a significant problem here is that the DRL electrode must be in contact with the lower right abdomen, thus requiring the use of cables or increasing the size of the device. That is, it is difficult to manufacture an ECG device the size of a credit card that uses DRL electrodes to measure two leads. Moreover, importantly, if the DRL electrode is placed adjacent to another electrode in contact with the body, the voltage of the adjacent electrode will be distorted because the voltage of the DRL electrode includes ECG signal components. Eliminating power line interference without using DRL electrodes is extremely difficult and requires specialized circuitry (In-Duk Hwang and Jhon G. Webster, Direct Interference Elimination of Two-Electrode Biopotential Amplifiers, IEEE Biomedical Engineering Transactions, No. 55, No. 11, pp. 2620-2627, 2008). Eliminating power line interference may require multiple filters with very high quality factors (Q), however, manufacturing and calibrating multiple filters can be challenging.

Dry electrodes have high electrode impedance and generate greater electric field interference. However, in ECG measurements, for user convenience, it is necessary to use dry electrodes attached to the housing surface of the ECG measuring device, rather than wet electrodes connected to cables. Furthermore, for user convenience, it is necessary to reduce the number of dry electrodes. It is also required that the DRL electrodes not come into contact with the right foot or the lower right part of the body. However, it is difficult to provide an ECG measuring device in the prior art that eliminates cables, uses a minimal number of electrodes, and eliminates electric field interference.

To address the aforementioned problems and necessities, this invention, for user convenience, eliminates the use of cables and instead employs dry electrodes. To simultaneously measure two limb leads, it utilizes two amplifiers and three electrodes connected to an electrode drive unit. For user convenience, the electrocardiogram device according to this invention provides a plate-shaped electrocardiogram device having two dry electrodes separated from each other on one surface and one dry electrode on another surface. Furthermore, this invention provides a method for eliminating electric field interference without using DRL electrodes.

As will be described later, an electrocardiogram (ECG) measuring device is disclosed in this invention, characterized by comprising three electrodes, with a concentrated electric field interference current flowing through one electrode connected to the electrode drive unit, and using two amplifiers connected to the other two electrodes besides the three electrodes. Each amplifier amplifies an ECG signal and simultaneously measures two ECG signals. Here, an amplifier means that the signal is amplified, and in a practical configuration, an amplifier may mean multiple amplification stages in series or a collection of active filters.

As described below, the prior art does not provide the technical solution provided by the present invention.

The Righter (US Patent No. 5,191,891,993) is equipped with three electrodes in its phenotypic device to obtain only one ECG signal.

Amluck (DE 201 19965, 2002) disclosed an electrocardiogram with two electrodes at the top and one electrode at the bottom, but measuring only one lead. Moreover, unlike this invention, Amluck has a display and input/output buttons.

Wei et al. (US Patent No. 6,721,591, 2004) used a total of six electrodes, including a ground electrode and an RL electrode. Wei et al. published a method for measuring four leads and calculating the remaining eight leads.

Kazuhiro (JP2007195690, 2007) equipped a device including a display with four electrodes, including a ground electrode.

Tso (US Publication No. 2008/0114221, 2008) discloses an instrument containing three electrodes. However, Tso uses one hand to simultaneously touch two electrodes to measure a limb lead, such as lead I. This allows only one lead to be measured at a time, so three measurements must be performed sequentially to obtain three limb leads. Alternatively, Tso directly measures enhanced limb leads that do not require direct measurement and uses a separate platform for this measurement.

Chan et al. (US Publication No. 2010/0076331, 2010) disclosed a watch comprising three electrodes. However, Cho et al. used three differential amplifiers to measure the three leads. Furthermore, Chan et al. used three filters connected to the respective amplifiers to reduce signal noise.

Bojovic et al. (US Patent No. 7,647,093, 2010) described a method for calculating a 12-lead signal by measuring three special (non-standard) leads. However, to measure three leads, including one limb lead (Lead I) and two special (non-standard) leads from the chest, five electrodes with a ground electrode on each side of a plate-shaped device and three amplifiers were used.

Saldivar (US Publication No. 2011/0306859, 2011) discloses a cellular communication cradle. Saldivar has three electrodes on one side of the cradle. However, Saldivar uses a lead selector to connect two of the three electrodes to a differential amplifier 68 to measure one lead sequentially (Figure 4C and segment [0054]), meaning Saldivar measures leads sequentially in three steps.

Berkner et al. (US Patent No. 8,903,477, 2014) proposed a method for calculating 12-lead signals using three or four electrodes placed on either side of a housing, through sequential measurements performed while the device is moved sequentially. However, the detailed structure and shape of the apparatus, including the internal connections of the respective electrodes, have not been provided. Crucially, Berkner uses an amplifier 316 and a filter module 304. For example, if two leads are measured using an amplifier 316 and a filter module 304, two measurements are performed sequentially. Berkner states, “In a three-electrode system, the reference electrode is different and shifts with each lead measurement. This can be accomplished by specifying software or hardware that includes an optional switch.” (...Therefore, in a system with only three electrodes, the reference electrode is different and changes with each lead measurement. This can be accomplished by specifying software and hardware/or, optionally, hardware that includes a switch.) The above technique indicates that Berkner uses an amplifier 316 and a filter 304 to measure one lead at a time and performs multiple measurements sequentially. That is, compared with the method proposed in this invention, which uses three electrodes and two amplifiers to simultaneously measure two leads, the method of Berkner et al. has many disadvantages.

Amital (US Publication No. 2014/0163349, 2014) generates a common-mode cancellation signal from three electrodes of a device equipped with four electrodes, wherein the common-mode cancellation signal is generated by coupling another electrode (see claim 1) to remove the common-mode signal. This is a prior art DRL method known to Amital.

Thomson et al. (US Publication No. 2015/0018660, 2015) disclosed a smartphone case with three electrodes. Thomson's smartphone case has a hole in the front allowing a view of the smartphone screen. However, no method was proposed for simultaneously measuring two leads using two amplifiers. Furthermore, because Thomson's device uses ultrasonic communication, there is a drawback where communication problems occur even when the smartphone and the device are slightly separated (approximately 1 foot). Additionally, if the user changes their smartphone, Thomson's smartphone case may not be compatible with existing smartphone cases.

Drake (US Publication No. 2016/0135701, 2016) has three electrodes on one side of a mobile device, providing six leads. However, Drake is described as "comprised of one or more amplifiers for amplifying analog signals received from the three electrodes" (paragraph [0025] and claim 4, "comprising one or more amplifiers configured to amplify analog signals received from the three electrodes"). Therefore, Drake is ambiguous regarding the essential part of the invention, namely, how many amplifiers to use and how to connect the amplifiers to the three electrodes. Drake also states that "ECG device 102 includes a signal processor 116 that can be configured to perform one or more signal processing operations on signals received from the right arm electrode 108, the left arm electrode 110, and the left leg electrode 112" (paragraph [0025]). Therefore, Drake receives three signals. Furthermore, it is ambiguous whether Drake receives the three signals simultaneously or sequentially. Additionally, Drake describes that "various embodiments disclosed herein can relate to handheld ECG devices for simultaneously acquiring six leads" (paragraph [0019]). At this point, Drake incorrectly, inappropriately, and ambiguously used the word "simultaneously." The structure of Drake's device is similar to that of the Thomson device. Drake places three electrodes on one side of its device. Therefore, similar to the Thomson device, it is difficult to simultaneously contact both hands and the body with all three electrodes.

The Saldivar (WO 2017/066040, 2017) device uses a lead selection stage 250 to connect three electrodes to an amplifier 210. Furthermore, the Saldivar performs six measurements one by one to obtain six leads. That is, the Saldivar cannot measure multiple leads simultaneously. The Saldivar can also measure three enhanced limb leads sequentially and directly.

Summary of the Invention

Technical problems to be solved

This invention addresses the aforementioned problems and aims to provide an electrocardiogram (ECG) device with three electrodes that simultaneously measures two limb leads using two amplifiers associated with two limb leads. Simultaneous measurement of two limb leads is medically important because sequentially measuring two leads is time-consuming and inconvenient. More importantly, two limb leads measured at different times may not correlate and could confuse detailed arrhythmia differentiation. For user convenience, the ECG device according to the invention includes a plate-shaped ECG device having two separate dry electrodes on one surface and one dry electrode on another surface. Furthermore, the invention provides a method for eliminating power line interference without using DRL electrodes. This invention discloses a convenient ECG measurement method involving contacting two electrodes with both hands and one electrode on the body, as well as an ECG measurement device with a suitable structure.

Technical solution

The electrocardiogram (ECG) device according to the present invention, which addresses the above-mentioned problems, has the following appearance, operating principle, structure, and usage method. The present invention solves the above-mentioned problems through systematic analysis circuit design and software production.

This application discloses an electrocardiogram (ECG) measurement device, comprising:

The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively.

Two amplifiers, respectively receiving the two electrocardiogram voltages from the first electrode and the second electrode;

Electrode drive section for outputting drive voltage;

The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part;

The first current detector is used to generate an output when two of the three electrodes are in contact with both hands;

A second current detector is used to generate an output when one of the remaining electrodes contacts the left leg;

An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals.

A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and

A communication device for transmitting two digital signals.

The microcontroller receives power from the battery, controls the analog-to-digital converter and the communication device, and measures two electrocardiograms when the first current detector and the second current detector generate outputs.

This application also proposes an electrocardiogram (ECG) measuring device, comprising:

The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively.

Two amplifiers receive two electrocardiogram voltages from the first electrode and the second electrode, respectively;

Electrode drive section for outputting drive voltage;

The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part;

The first current detector is used to generate an output when two of the three electrodes are in contact with both hands;

A second current detector is used to generate an output when one of the remaining electrodes contacts the left leg;

An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals.

A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and

A communication device for transmitting the two digital signals.

The microcontroller receives power from the battery, controls the analog-to-digital converter and the communication device, and measures lead I when only the first current detector produces an output.

This application also proposes an electrocardiogram (ECG) measuring device, comprising:

The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively.

Two amplifiers receive two electrocardiogram voltages from the first electrode and the second electrode, respectively;

Electrode drive section for outputting drive voltage;

The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part;

An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals.

A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and

A communication device for transmitting the two digital signals.

The microcontroller receives power from the battery, controls the analog-to-digital converter and the communication device, and measures two electrocardiograms when the 6-lead measurement button (1331) displayed on the smartphone is touched.

Figure 1 illustrates an electrocardiogram (ECG) measuring device 100 according to the present invention. The ECG measuring device 100 includes three electrodes 111, 112, and 113 on its surface. Two electrodes 111 and 112, spaced apart by a predetermined interval, are mounted on one surface of the ECG measuring device 100, and one electrode 113 is mounted on the other surface.

Figure 2 illustrates a method by which a user measures an electrocardiogram (ECG) in six-channel mode using the ECG measuring device 100 according to the present invention. The user touches electrodes 111 and 112, located on one side of the ECG measuring device 100, with both hands, and touches electrode 113, located on the other side, with their left lower abdomen (or left leg). When three electrodes are in contact with the body in this manner, two limb leads can be measured, and four additional leads can be calculated as described below. The measurement method in Figure 2 provides the most convenient method for obtaining a six-channel ECG according to the present invention. Furthermore, the present invention provides a device best suited to the measurement method of Figure 2. The principle of the measurement method is as follows.

The existing 12-lead electrocardiogram (ECG) is described in ANSI/AAMI/IEC 60601-2-25:2011, Medical Electrical Equipment – Part 2-25: Particular requirements for basic safety and basic performance of electrocardiographs. In the existing 12-lead ECG, the three limb leads are defined as follows: Lead I = LA - RA, Lead II = LL - RA, Lead III = LL - LA. In the above formulas, RA, LA, and LL are the voltages of the right arm, left arm, left leg, or body parts near these limbs, respectively. In this case, to eliminate electric field interference, the right leg (DRL) electrode is typically used in the prior art. Based on the aforementioned relationship, one limb lead can be obtained from the other two limb leads. For example, Lead III = Lead II - Lead I. Three enhanced limb leads are defined as follows. aVR = RA - (LA + LL/2), aVL = LA - (RA + LL/2), aVF = LL - (RA + LA/2). Therefore, three enhanced limb leads can be obtained from two limb leads. For example, aVR = -(I + II/2). Therefore, if two limb leads are measured, the remaining four leads can be calculated and obtained. Therefore, this invention discloses a device that uses three electrodes and two amplifiers to simultaneously measure two leads to provide six leads. Here, one amplifier means that the signal is amplified, and in a practical configuration, an amplifier can consist of a collection of multiple amplification terminals or active filters connected in series. A standard 12-lead electrocardiogram consists of 6 leads from V1 to V6 and 6 pre-recorded leads.

The modified chest lead (MCL), similar to the pre-coded lead, is very useful in medicine. On the other hand, in the principle of the invention, the voltage of the electrode not connected to the amplifier is substantially equal to the common circuit in the signal band. Therefore, the electrocardiogram measuring device 100 according to the invention is suitable for measuring one of the six MCLs from MCL1 to MCL6. This is because each MCL is based on the voltage of the body part connected to the left hand at the corresponding recorded lead location.

Figure 3 illustrates a method by which a user measures MCL1 using the electrocardiogram (ECG) device according to the present invention in MCL mode. For example, using the ECG device according to the present invention, to measure MCL1, as shown in Figure 3, the user touches electrodes 111 and 112 disposed on one side of the ECG measuring device 100 with both hands, and contacts electrode 113 disposed on the other surface with the MCL position (e.g., the V1 position when measuring MCL1). In the present invention, in order for the user to measure MCLn, the user needs to contact the electrode 113 with the MCLn position on the user's body, i.e., the Vn position.

Now, embodiments of the electrocardiogram (ECG) measuring device according to the present invention will be described with reference to Figures 4 and 5. Figure 4 is an equivalent circuit model illustrating the principle and embodiment of eliminating electric field interference in the ECG measuring device according to the present invention. Figure 5 is an equivalent circuit model of an embodiment in which two single-ended input amplifiers and an electrode driver are used to simultaneously measure two channels of an ECG in the ECG measuring device according to the present invention.

Referring to Figure 4, current source 450 is used to model power line interference. Additionally, in Figure 4, the human body is labeled 430 and modeled by three electrode resistors 431, 432, and 433 connected to each other at a single point. Furthermore, in Figure 5, an ECG signal is modeled as a voltage source 461 and 462 existing between two electrode resistors. In this invention, since three electrodes are used, two ECG voltage sources 461 and 462 are simulated in the human body in Figure 5. This is because there are three ECG voltages on the three electrodes (since there are three when selecting two electrodes from three), but only two ECG voltages are independent. This simplifies the power line interference modeling in Figure 4 and the ECG signal modeling in Figure 5. However, the model is suitable for clarifying the problem to be solved. Furthermore, the above model clearly suggests what the invention should be designed for. Moreover, the invention can be easily understood by using the above model. The invention is designed based on the above model. Since the prior art does not use the above model, the prior art cannot accurately propose a solution to the problem.

As will be described later, the invention can be expressed in various embodiments. However, the various embodiments of the invention are generally based on the following principles of the invention. The principles of the invention are designed in accordance with the invention. The principles of the invention differ from those used in the prior art in that they do not use DRL electrodes.

A key unresolved issue in existing ECG measurement devices that do not use DRL electrodes is the elimination or reduction of electric field interference. As shown in Figure 4, electric field interference in ECG measurement devices, due to their relatively large output impedance, is generated by a current source with essentially infinite output impedance. (In Figure 4, the electric field interference current source is represented as 45°.) Therefore, to eliminate electric field interference, the impedance from the electric field interference current source to the human body needs to be minimized. The impedance from the electric field interference current source to the human body is the sum of the human body's own impedance and the impedance of the ECG measurement device. Consequently, it is necessary to minimize the impedance of the ECG measurement device as seen through the three electrodes. On the other hand, there is a so-called electrode impedance, or electrode resistance, between the electrodes used to measure the ECG and the human body (431, 432, 433 in Figure 4). Therefore, to minimize the effect of electrode impedance and measure ECG voltage, the ECG measurement device must have high impedance. Thus, the ECG measurement device must satisfy two opposing conditions: it must have low impedance to eliminate electric field interference and it must have high impedance to measure ECG voltage.

To satisfy two opposing conditions, for example, when using three electrodes, three resistors with larger values are connected to each of the three electrodes, the other ends of the three resistors are connected together as a point, and the common-mode signal of the three electrodes is negatively fed back to the point connected to the three resistors. However, this method is practically difficult to use. This is because the impedance of the electric line interference current source is large, so the magnitude of the electric line interference current does not decrease. Therefore, in this case, the electric line interference voltage induced in the three resistors is still large. Otherwise, the amplifier may saturate. In addition, since the magnitude of the electric line interference current does not decrease and the impedances of the respective electrodes can be different, different electric line interference voltages are induced at high levels for each respective electrode. Therefore, even when using a differential amplifier, it is difficult to eliminate the electric line interference induced at the respective electrodes. This is a difficulty of the prior art.

Therefore, in this invention, the electric field interference current is concentrated and flows only to one electrode installed in the electrocardiogram (ECG) measuring device. To this end, while connecting three electrodes to the human body, the electric field interference current source minimizes the impedance of the ECG measuring device entering through one electrode. This then minimizes the electric field interference voltage induced in the human body by the electric field interference current source (denoted as 440ν in Figure 4). Since the induced electric field interference voltage is minimized, the input impedance of the other electrodes in the ECG measuring device can be increased, and the ECG voltage can be measured accurately. Importantly, in the electrode where the electric field interference current is concentrated, the electric field interference voltage is induced to be high; therefore, this electrode should not be used for measurement. Therefore, in this invention, when using three electrodes, measurement is performed using two electrodes and two amplifiers that receive ECG signals from the two electrodes. In particular, it should be noted that since only two electrodes must be used for measurement in an ECG measuring device using three electrodes, two differential amplifiers cannot be used. Furthermore, when negative feedback is used, if negative feedback is performed across all frequency bands, the electrocardiogram signal is generated at the electrode side and fed back, mixing with the electric field interference voltage. Therefore, negative feedback should only be performed at the electric field interference frequency. A detailed description of the invention will be described below with reference to the accompanying drawings.

In Figure 4 and the following figures, for convenience, only a portion of the electrocardiogram (ECG) measuring device 100 according to the invention is shown. In Figure 4, the ECG measuring device 100 according to the invention includes three electrodes 111, 112, and 113, two amplifiers 411 and 412, and an electrode driver (specifically, a bandpass filter) 413. Referring to Figures 4 and 5, the two amplifiers 411 and 412 used in this invention are not differential amplifiers, but single-ended input amplifiers.

A key feature of the embodiment shown in FIG. 4 of the present invention is that the electrocardiogram measuring device 100 according to the present invention includes an electrode driver 413 represented by a bandpass filter. That is, in FIG. 4, the electrode driver 413 may have bandpass frequency characteristics. Therefore, in the present invention, the electrode driver 413 can be described as a bandpass filter. The input of the electrode driver 413 is connected to an electrode 112. The output of the electrode driver 413 drives the electrode 113 (feedback to the electrode 113) through a resistor 423. The resonant frequency or peak frequency of the electrode driving unit (i.e., the bandpass filter 413) is the same as the frequency of the power line interference. In addition, the bandpass filter 413 has a large Q. In FIG. 4, the input impedance of the bandpass filter 413 is large, while the output impedance is small. The element value of the resistor 423 is represented by R0. In the present invention, for convenience, the resistor 423 is regarded as the output impedance of the electrode driver 413.

In this invention, two of the three electrodes are connected to the analog circuit via resistors 421 and 422, with a resistance value of RI. Resistors 421 and 422 are considered to be the input impedances of amplifiers 411 and 412.

In Figure 4, 430 represents a human body model. There is contact resistance between the human body and the electrodes, commonly referred to as electrode impedance. In Figure 4, the electrode impedances (electrode resistances) existing between the human body 430 and the three electrodes 111, 112, and 113 are represented as resistances 431, 432, and 433, respectively. The device values for electrode resistances 431, 432, and 433 are represented by Re1, Re2, and Re3, respectively.

In Figure 4, 450 is a power line interference current source used for modeling power line interference. The current i_n of the power line interference current source 450 flows through the human body 430 and the three electrodes 111, 112, and 113 according to the present invention.

i _n =i _n1 +i _n2 +i _n3 ……………………(Formula 1)

The circuitry of the electrocardiogram device 100. When the electric field interference currents flowing through the three electrodes 111, 112, and 113 are represented by in1, in2, and in3 respectively, the following condition holds according to Kirchhoff's current law.

Equation 1

For circuit analysis, the electric field interference induced in the human body 430 is represented by νbody. In Figure 4, νn1, νn2, and νn3 represent the electric field interference voltages of electrodes 111, 112, and 113, respectively.

In Equation 1, the currents are as follows.

Equation 2

Equation 3

Equation 4

at this time

Equation 5

The transfer function of the bandpass filter 413 is represented by -H(f). Using the above equation, the following equation is obtained.

Equation 6

In this invention, the device values of the circuit in Figure 4 are used to achieve the following approximations (Equations 7 and 8). Equations 7 and 8 are important components of this invention.

Equation 7

R _i >> R _e1 , R _e2 , or R _e3 ……………………………… (Formula 7)

Equation 8

R _i >> R _o ……………………………………………(Equation 8)

Then, the following approximation is established.

Equation 9

From Equation 9 above, we obtain the following equation.

In Equation 10, if there is no feedback, i.e., H(f＝0), then the following holds true.

Equation 11

v _body ≈(R _o +R _e3 )i _n if H(f)＝0…………(Equation 11)

By comparing Equations 10 and 11, we can see that the effect of this invention is to reduce the influence of the power line interference current _{_in_} to the feedback quantity, i.e., (1+H(f)). Therefore, at the resonant frequency of the bandpass filter, when the gain |H( _{f_o} )|>1, _{v_body} ≈0. This proves the principle of eliminating power line interference in this invention.

The following equations are confirmed by using Equations 2 and 10.

For v _{_n3}, the following results are obtained. From the above results, we can use v _{_body} ≈ 0 and i _{_n3} ≈ i_{_n.}

Equation 13

v _n3 ≈v _body -i _n3 R _e3 ≈-i _n R _e3 …………(Equation 13)

From equations 12 and 13, we can confirm the following equations.

|v _n3 |＞＞|v _n1 |……………(Equation 14)

This is the result of feedback |H(f)|. Due to its large size, almost all the electric field interference current flows through the feedback electrode (electrode 113 in Figure 4), thus contaminating the feedback electrode with electric field interference, while the non-feedback electrodes (electrodes 111 and 112 in Figure 4) are electric field lines. This means they are almost unaffected by interference. This implies that for ECG measurements, the feedback electrode should not be used; only the non-feedback electrode should be used. Therefore, the effects of electric field interference cannot be eliminated by using a differential amplifier with inputs connected to electrodes 111 and 113 or a differential amplifier with inputs connected to electrodes 112 and 113. This is one of the significant problems with the prior art.

The principle of obtaining two ECG channel signals using three electrodes according to the present invention will be described below. Figure 5 is the equivalent circuit when measuring an electrocardiogram using the electrocardiogram device according to the present invention.

In Figure 5, ν1, ν2, and ν3 represent the ECG signal voltages of electrodes 111, 112, and 113, respectively. The voltage v2 of electrode 112 was obtained by analyzing the equivalent circuit using the following superposition principle.

In Equation 15, the symbol || represents the value of the parallel resistance. As mentioned above, the conditions of Equations 7 and 8 can be assumed in Equation 15. Then, the voltage ν2 is approximated as follows.

Equation 16

Therefore, under the conditions of equations 7 and 8, the voltage ν1 is as follows.

Equation 17

From the baseband signal above, it can be confirmed that |H(f)| < 1 when _v2 ≈ _vb

Figure 6 shows the frequency response of the bandpass filter used in the electrocardiogram measurement device according to the present invention. In Figure 6, the resonant frequency of the bandpass filter is 60 Hz, the gain at the resonant frequency is 20, and Q = 120. Figure 7 shows that when using the bandpass filter of Figure 6, νb can be obtained with 98% accuracy at frequencies below 40 Hz.

Similarly, the voltage ν1 of electrode 1 is obtained as follows.

Equation 18

When the conditions of Equations 7 and 8 are used, the voltage ν1 is approximately as follows.

Equation 19

v _₁ ≈ +v_{_d} +v _{_b}-v_₂ H(f)

≈v_{_a}+v_₂ …………………………………(Equation 19)

The above equation is obtained using Equation 16. From the above equation, we obtain the following Equation 20, and νa can be obtained through this equation. It can be seen from Equation 20 that νa can be obtained without the influence of the bandpass filter.

Equation 20

v ₁ -v ₂ ≈+v _a ……………………(Equation 20)

Therefore, according to the present invention, the principle of using two single-ended amplifiers to obtain signals from two ECG channels has been described.

Figure 8 is an equivalent circuit model illustrating the principle and embodiment of eliminating electric line interference using a common-mode signal with two electrodes in an electrocardiogram (ECG) measuring device according to the present invention. Naturally, even when using a common-mode signal, the electric line interference current is concentrated and flows through electrode 832, the output of electrode driver 813 is fed back to electrode 832, and the electric line interference voltage exists in electrode 832. Figure 9 is an equivalent circuit model of an embodiment using a differential amplifier 811 and a single-ended input amplifier 812 to simultaneously measure two channels of the ECG when using the method of Figure 8, i.e., using a common-mode signal to remove electric line interference. Similar to the two single-ended input amplifiers previously described, two ECG voltages can be obtained.

For simplicity, the circuit analysis in Figures 8 and 9 is omitted. In the embodiments of Figures 8 and 9, as in the embodiments of Figures 4 and 5, the electrode driving unit, i.e., the bandpass filter 813, is applied by a driving voltage through an output impedance Ro and an electrode 112 in contact with a human body part. That is, the electrode 112 is not connected to an amplifier for measuring ECG voltage, but is connected to the electrode driver 813 through an output impedance 823. In other words, the electrode 112 is not used to measure ECG voltage. When the peak value of the bandpass filter is large, in order to achieve |H(f)| << 1 in the signal band, the transfer function H(f) of the bandpass filter can be corrected or compensated.

In Figure 8, a bandpass filter 813 is used as an electrode driver, but in Figure 10, a constant voltage source 1013 is used as an electrode driver. The constant voltage source 1013 applies a driving voltage to a portion of the human body in contact with electrode 112 via a resistor 1023 with a small resistance value R₀ and electrode 112. Most of the power line interference current flows through electrode 112. To further concentrate the power line interference current, the output impedance 1023 of electrode driver 1013 can be reduced. This method is less effective at eliminating power line interference compared to the previous method using a bandpass filter. In the embodiment of Figure 10, in addition to the electrode where the power line interference current is concentrated and flows, two ECG voltages are simultaneously amplified by using two amplifiers connected to the two electrodes. In the embodiment of Figure 10, a differential amplifier 1011 and a single-ended input amplifier 1012 are used. The output of a single-ended input amplifier 1012 can include a small amount of power line interference, and a bandpass filter 1033 can be used to further reduce power line interference.

In Figures 5, 9, and 10, an electrode driver with low output impedance is typically used to drive one electrode to reduce power line interference. The output of the electrode driver is transmitted to the human body part in contact with the electrode. Once the power line noise is reduced, two single-ended input amplifiers can be used to amplify the two ECG voltages received from the two electrodes, and one single-ended input amplifier and one differential amplifier can be used.

The principle of this invention is summarized as follows. The condition that the input impedance of the electric field interference current source should decrease upon entering the electrocardiogram (ECG) measuring device is satisfied by reducing the output impedance of the electrode driver connected to one electrode, and the condition that the input impedance of the ECG signal voltage must increase upon entering the ECG measuring device is satisfied by increasing the input impedance from the two different electrodes. Through the above method, the ECG measuring device according to the invention can accurately measure the ECG signal voltage while reducing electric field interference. Therefore, the output impedance of the electrode driver in the ECG measuring device according to the invention is less than the respective input impedances of the two amplifiers.

As described above, according to the present invention, an example of simultaneously measuring the two ECG voltages is provided by using two amplifiers with large input impedance to receive two ECG voltages from two electrodes, while eliminating power line interference by applying the output of one electrode driver to one electrode.

Beneficial effects

The electrocardiogram (ECG) measuring device according to the invention provides six ECG leads that can be obtained simultaneously using a minimum number of electrodes (specifically, three electrodes). When the ECG measuring device according to the invention is used in MCL mode, one limb lead (specifically, lead I) and one MCL can be measured.

Since the portable electrocardiogram (ECG) measuring device according to the invention is the size of a credit card, it is easy to carry, and thus allows for the convenient acquisition of multiple ECGs regardless of time and place. Furthermore, since it communicates wirelessly with a smartphone, it can be used conveniently without any substantial limitation on the distance between the ECG measuring device according to the invention and the smartphone.

Furthermore, in the electrocardiogram measuring device according to the present invention, when not in use, all circuits except the current sensor are disconnected, and only the microcontroller enters sleep mode. When in use, only the required circuits are powered, and the microcontroller enters activation mode, thus minimizing the power consumption of the built-in battery of the electrocardiogram measuring device.

Furthermore, the electrocardiogram measuring device according to the present invention does not include a mechanical power switch or selector switch, thereby achieving miniaturization and thinness, eliminating the need for users to use switches unnecessarily, avoiding the possibility of switch failure, limited lifespan, and increased manufacturing costs.

Furthermore, since the electrocardiogram measuring device according to the present invention does not include a display such as an LCD, it can be manufactured in a compact size and is easy to carry without causing display failure and deterioration or an increase in manufacturing cost.

Attached Figure Description

Figure 1 is a perspective view of an electrocardiogram measuring device with three electrodes according to the present invention.

Figure 2 illustrates a method for measuring an electrocardiogram (ECG) in a 6-channel mode using the ECG measuring device according to the present invention.

Figure 3 illustrates a method for measuring an electrocardiogram (ECG) in MCL mode using the ECG measuring device according to the present invention.

Figure 4 is an equivalent circuit model illustrating the principle and embodiment of eliminating electric field interference in the electrocardiogram measurement device according to the present invention.

Figure 5 is an equivalent circuit model of an embodiment of an electrocardiogram measuring device according to the present invention, which uses two single-ended input amplifiers and a bandpass filter (electrode drive unit) to simultaneously measure two channels of an electrocardiogram.

Figure 6 shows the frequency response of a bandpass filter used as an electrode drive unit in an electrocardiogram measuring device according to the present invention.

Figure 7 shows the frequency response of a signal channel in the electrocardiogram measuring device according to the present invention when a bandpass filter is used as an electrode drive unit.

Figure 8 is an equivalent circuit model illustrating the principle and embodiment of using common-mode signals to eliminate power line interference in the electrocardiogram measurement device according to the present invention.

Figure 9 is an equivalent circuit model of an embodiment of the electrocardiogram measurement device according to the present invention, which uses a differential amplifier, a single-ended input amplifier, and a bandpass filter (electrode drive unit) to simultaneously measure two channels of electrocardiogram when using a common-mode signal to eliminate power line interference.

Figure 10 shows another embodiment of the electrocardiogram measuring device according to the present invention, which simultaneously measures two channels of an electrocardiogram using a differential amplifier, a single-ended input amplifier, and a constant voltage generator (electrode drive unit).

Figure 11 is a block diagram of a circuit embedded in an electrocardiogram measuring device according to the present invention.

Figure 12 is an operation flowchart of the electrocardiogram measurement device according to the present invention.

Figure 13 is the initial screen of a smartphone when the smartphone application is executed to use the electrocardiogram measurement device according to the present invention.

Figure 14 is a flowchart of a smartphone application used when using the electrocardiogram measuring device of the present invention.

Figure 15 shows an electrocardiogram measuring device according to the present invention equipped with a blood test strip insertion port.

Figure 16 is an example of an electrocardiogram measuring device according to the present invention implemented in the shape of a smartwatch.

Figure 17 is an example of implementing the electrocardiogram measuring device of the present invention in a ring shape.

Figures 18 and 19 are examples of an electrocardiogram measuring device according to the present invention when measuring an electrocardiogram by connection to trousers.

Figures 20 and 21 show the shapes of watch straps that can be connected to the watch by using two or one sliding guide of the electrocardiogram measuring device, which serves as the electrode according to the invention.

Figure 22 is a perspective view of an electrocardiogram measuring device with four electrodes according to the present invention.

Detailed Implementation

In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In this embodiment, the electrocardiogram (ECG) measuring device is described as comprising three electrodes, but is not limited thereto; the ECG measuring device may be a device comprising more than three electrodes. Important embodiments of the invention have previously been described using Figures 4 through 10 to explain the principles of the invention.

To increase portability, the portable electrocardiogram (ECG) measuring device according to the invention is preferably credit card shaped and has a thickness of 6 mm or less. Since the portable ECG measuring device according to the invention is portable, it uses a battery, and when using a CR2032 type battery, it can be used for approximately 2 years.

Additionally, a mechanical power switch or selector switch can be omitted to miniaturize portable ECG measurement devices and to reduce power consumption by eliminating the need for a display.

The portable electrocardiogram (ECG) measuring device according to the present invention is characterized by the use of a current sensor to eliminate the need for a mechanical power switch or selector switch. The current sensor is always supplied with the power required for operation and waits to generate an output signal when an event occurs. When a user touches multiple electrodes to the human body to measure an ECG, a loop of minute current flows through the body. Therefore, when the human body is electrically connected to the current sensor, the current sensor causes the minute current to flow through the body, and the current sensor senses the minute current and generates an output signal. To increase battery life, when the portable ECG measuring device is not in use, only the current sensor operates, the remaining circuitry is powered off, and the microcontroller waits in sleep mode. At this time, when an event occurs where both hands touch two electrodes and the current sensor generates an output signal, the microcontroller is activated to power the ECG circuitry and perform the ECG measurement. The current sensed by the current sensor is provided by a battery supplied in the portable ECG measuring device and is direct current (DC).

The electrocardiogram (ECG) measuring device 100 according to the present invention may further include the function of measuring blood characteristics such as blood glucose levels, ketone levels, or international normalized ratio (INR). Therefore, in this embodiment, the ECG measuring device 100 will be used as an example to illustrate the simultaneous measurement of ECG and blood characteristics. The blood glucose or ketone levels can be measured using the amperometric method. The INR is a measure of coagulation tendency and can be determined using capillary blood impedance, amperometric, or mechanical methods. A blood test strip for the blood characteristic test is inserted into a blood test strip insertion port, which is located in the housing of the ECG measuring device according to the present invention.

In embodiments of the electrocardiogram (ECG) measuring device 100 according to the present invention, a thermometer function may be included. For the ECG measuring device 100 according to the present invention to include a thermometer function, a suitable shape is a contact type, and a suitable temperature sensor is a thermistor. To measure body temperature using the ECG measuring device 100 according to the present invention, which includes a thermometer function, the user contacts their forehead or armpit with a portion of the ECG measuring device 100 to which the temperature sensor is attached. For accurate body temperature measurement, the skin temperature should not be altered by the location on the ECG measuring device 100 to which the temperature sensor is mounted.

Figure 11 shows a block diagram of the circuitry built into the electrocardiogram (ECG) measuring device 100 according to the present invention. To illustrate the invention, although not shown in Figure 11, the ECG measuring device according to the present invention may include a blood testing circuit, a blood test strip insertion port, etc. The functions and operations of the respective blocks in Figure 11 are as follows. When a user touches a pair of electrodes 111, 112 with both hands, the ECG current sensor 1140 allows a small current to flow through the two hands and detects the flow of the small current. The current sensor 1140 generates a signal to change the microcontroller 1180 from sleep mode to active mode. The microcontroller 1180 then powers on the ECG measuring circuit 1160 and the AD converter 1170. The ECG measuring circuit 1160 amplifies two ECG signals from two amplifiers and generates two outputs. The AD converter 1170 receives the two outputs of the ECG measuring circuit 1160, and the output of the AD converter 1170 is transmitted to the smartphone 210 via the wireless communication device 1190 and antenna 1192. The smartphone 210, which receives the data, displays multiple ECG waveforms. After a certain period of measurement, the microcontroller 1180 enters sleep mode and waits for the next touch from both hands.

If the ECG measuring device of this invention is touched with both hands and the lower left abdomen, six leads can be displayed at once. However, when it is inconvenient to touch the ECG measuring device with the lower left abdomen or when only one lead is being measured, the ECG measuring device automatically determines whether the user intends to measure only one lead or all six leads. When the user touches the ECG measuring device with both hands to measure only one lead, the current sensor 1140 senses only one current. Then, only lead I is displayed on the smartphone. When the user touches the ECG measuring device with both hands and the lower left abdomen to measure six leads, the current sensor 1140 and the current sensor 1150 sense the current together. Then, all six leads are displayed on the smartphone. The separate boxes shown in Figure 11 can be implemented using commercially available components with existing technology.

Figure 12 is an operation flowchart of the electrocardiogram (ECG) measuring device 100 according to the present invention when measuring the ECG. To allow a user to measure the ECG, the pair of electrodes 111 and 112 of the ECG measuring device 100 are respectively touched 1210 by both hands. Then, the current sensor, which senses the minute current flowing through the body between the two hands, generates an output signal 1215. The output signal generates an interrupt in the microcontroller 1180 to activate the microcontroller 1180 (1220). The activated microcontroller 1180 activates the wireless communication device 1190. Hereinafter, the case where the wireless communication device 1190 is a Bluetooth Low Energy device will be described. The wireless communication device 1190 of the ECG measuring device 100 is advertised as a Bluetooth Low Energy peripheral device 1225. At this time, a smartphone scanning as a Bluetooth Low Energy central device discovers the ECG measuring device 100 and attempts to connect. If the ECG measuring device 100 approves the connection, the smartphone and the ECG measuring device 100 are connected to Bluetooth Low Energy 1230. At this point, the ECG measuring device 100 can determine whether the user has actually touched the ECG measurement button on the smartphone to measure an ECG 1235.

When an ECG measurement request is confirmed, the microcontroller 1180 turns on the power supply 1240 of the ECG measurement circuit 1160. This can be done by connecting the output pin of the microcontroller 1180 to the ECG measurement circuit 1160 and setting the voltage of the output pin to High. Next, the current sensor 1245 is used to check whether the pair of electrodes 111, 112 are touched by both hands. This step determines when the microcontroller 1180 starts measuring the ECG, i.e., when the AD conversion begins. Specifically, it checks whether both hands are in continuous contact with the electrodes 111, 112.

Following the above process, the microcontroller 1180 initiates ECG measurement 1250. That is, the microcontroller 1180 performs AD conversion according to a preset AD conversion cycle and produces the AD conversion result. In this invention, two ECG signals are measured. The measured ECG data is sent to the intelligent collector 210 (1255), and when a preset measurement time, for example, 30 seconds has elapsed, the microcontroller 1180 enters sleep mode 1260.

All circuitry in Figure 11 is powered by a built-in battery in the electrocardiogram (ECG) measuring device 100. There may be no mechanical power switch, mechanical selector switch, or display screen in Figure 11. In Figure 11, when the ECG measuring device 100 is not measuring, the ECG current sensor and the microcontroller 1180 each consume approximately 1 µA, and all other modules are completely powered off.

The electrocardiogram (ECG) measuring device 100 according to the present invention is used in conjunction with a smartphone 210. Figure 13 shows the initial screen of the smartphone when the smartphone application according to the present invention is executed. When the smartphone application is executed, touch buttons 1331, 1332, 1334, 1336, 1342, 1344, 1346, and 1350 are displayed on the display 1320 of the smartphone 210. ECG-related buttons 1331, 1332, 1334, and 1336 are configured in the ECG frame 1330. When the ECG measuring device 100 according to the present invention includes a function for measuring blood characteristics, blood characteristic-related buttons 1342, 1344, and 1346 are configured in the blood glucose compartment 1340. To measure ECG, the user selects and touches one of the ECG measurement mode buttons 1331 and 1332. When the user measures ECG in 6-channel mode, button 1331 is touched. When the user measures ECG in MCL mode, button 1332 is touched. Then, when the user touches the pair of electrodes 111, 112 of the ECG measuring device 100 with both hands, the ECG measuring device 100 measures the ECG as described above. The data is displayed in a graph format on the smartphone display 1320 and stored in the smartphone 210. To view previously stored ECG measurement data in a graph format, touch the open button 1334. To send data to a doctor or hospital, touch the send button 1336. The settings button 1350 is used to record the user's name, date of birth, gender, address, etc., or to set options.

Figure 14 shows a flowchart of a smartphone application according to the present invention. For convenience, only the process of measuring an electrocardiogram (ECG) will be described. As shown in Figure 14, the ECG measurement process consists of two main trunks: a central trunk 1422, 1424, 1426, 1428, 1430, 1432 and a Bluetooth Low Energy (BLE) trunk 1452, 1454. After launching the application, various buttons 1410 appear on the smartphone display 1320, and then the BLE trunks 1452, 1454 are activated to perform Bluetooth Low Energy communication. The user who wants to measure an ECG touches one of the ECG measurement buttons 1331, 1332, 1422.

When a user touches touch 1422 of either ECG measurement button 1331 or 1332, an ECG measurement request signal is sent to the BLE levers 1452 and 1454 (1424). Additionally, depending on the ECG measurement mode, a message 1424 to the contact electrodes is displayed on the smartphone display 1320 according to the ECG measurement mode. The BLE levers 1452 and 1454 send the ECG measurement request signal 1454 to the ECG measurement device 100.

The ECG measuring device 100, upon receiving an ECG measurement request signal, performs the ECG measurement task described in FIG12 to retransmit the ECG data measured by BLE stems 1452 and 1454. The BLE stems 1452 and 1454 transmit the ECG data received from the ECG measuring device 100 to the central stems 1422, 1424, 1426, 1428, 1430, and 1432. The central stems 1422, 1424, 1426, 1428, 1430, and 1432 receive the ECG data. The received ECG data is displayed in a chart format on the central stems 1422, 1424, 1426, 1428, 1430, and 1432 of the smartphone display screen 1320. After all ECG measurements are completed, the measured ECG data is stored in a file format on the smartphone storage device. When the measured ECG data is displayed in the form of a graph on the smartphone display 1320, the smartphone application waits for the user to close the application 1432 by pressing the application exit button.

According to the present invention, the user can obtain the desired results without any abnormalities by using the electrocardiogram measuring device 100, which has no mechanical switches or selector switches and a display, and by using a simplified smartphone application, in all possible operating sequences.

As described above, the present invention has been described in detail with respect to the use of a single electrocardiogram measuring device 100 and a smartphone application for measuring electrocardiograms. However, the electrocardiogram measuring device 100 according to the present invention is not limited and can additionally measure a variety of measurement items.

As described above, the electrocardiogram measuring device 100 according to the present invention may further include the function of measuring blood characteristics. In this case, one embodiment of the electrocardiogram measuring device 1500 with the added function of measuring blood characteristics according to the present invention includes a blood characteristic test strip insertion port 1510 into which a blood characteristic test strip 1520 can be inserted, which can be configured, and one of its shapes may be as shown in FIG15.

The electrocardiogram (ECG) measuring device 100 according to the present invention has been described so far as being implemented in a plate-like form. However, the ECG measuring device according to the present invention uses, in principle, a minimal filter and has a simple circuit structure, thus allowing it to be manufactured in a small size. Therefore, the ECG measuring device according to the present invention is characterized by low battery power consumption. Therefore, the ECG measuring device according to the present invention is suitable for implementation in the shape of a watch or a ring. In particular, when the ECG measuring device according to the present invention is implemented as a watch or a ring, it is suitable for the user to wear at all times and has the advantage of being able to be used in conjunction with a photoplethysmography (PPG) device.

Photoplethysmography (PPG) uses LEDs to emit light into the skin and measures the reflected or transmitted light. Recently, PPGs built into smartwatches have been able to provide heart rate, heart rate variability (HRV), and respiratory rate (BR). HRV provides a wealth of information about an individual's health. HRV is used for sleep analysis or stress analysis, and also for detecting arrhythmias such as atrial fibrillation. Typically, HRV analysis is performed using an ECG, but recently, PPGs have also been used for analysis. PPGs included in patient monitoring equipment used in hospitals measure oxygen saturation and issue alerts when oxygen saturation is low. Recently, light signals have been captured using cameras installed in smartphones, and these signals can be used to detect the occurrence of arrhythmia symptoms. Therefore, by mounting a PPG on a watch or watch band, the occurrence of arrhythmia symptoms can be conveniently detected. Therefore, when the photoplethysmography device and the electrocardiogram measuring device according to the invention are mounted together on a watch or ring, the photoplethysmography device generates an alarm signal when an arrhythmia symptom is detected, and the user who receives the alarm signal uses the electrocardiogram measuring device according to the invention to measure an electrocardiogram.

For user convenience and accuracy of electrocardiogram (ECG) measurements, the placement of the ECG electrodes is important. Several examples of implementing the ECG measurement device according to the present invention in a watch will be described with reference to FIG16.

In the first example, three ECG electrodes can be mounted on both sides of the watch band. In Figure 16, one ECG electrode 111 is mounted on the inner surface of the watch band, the surface that contacts the wrist, while two electrodes 112 and 113 are located on the outer surface of the watch band, the surface that does not contact the wrist. In this example, when the user wears the watch on their left wrist, electrode 111 contacts the left wrist, electrode 112 is touched on the left lower abdomen or chest, and the fingers of the right hand are touched on electrode 113 to measure the ECG.

In the second example, an ECG electrode 1610 can be mounted on the bottom of the watch. In this case, electrode 1610 is always in contact with the wrist of the person wearing the watch, and in order to allow the user to measure ECG, electrode 112 is in contact with the lower left abdomen or chest, and electrode 113 is in contact with a finger of the hand without the watch.

In the third example, another part of the body, such as 1640, can be used to replace electrode 113 of Figure 16.

When the electrodes are mounted on a watch or watchband, for convenient and accurate ECG measurement by the user, in all the above cases, if the electrodes are mounted on the watch or watchband, one electrode 112 is mounted on the outer surface of the watchband on the inside of the wrist (not on the back of the hand, but on the palm), that is, the watchband does not contact the surface of the wrist. This is to allow the electrode 112 to comfortably contact the user's lower left abdomen or chest area. Additionally, when all the above electrodes are mounted on the watch or watchband, the capacitance chromatograph 1630 mounted on the bottom of the watch can analyze the optical volumetric signal and generate an alarm for the user.

The electrocardiogram (ECG) measuring device according to the present invention can be implemented in the shape of a ring. In this case, the ring is worn on the thumb or little finger for convenient ECG measurement. Figure 17 shows an example of implementing the ECG measuring device of the present invention in a ring shape. In Figure 17, one of the three electrodes 111 is in contact with the wearing finger, while electrodes 112 and 113 are not in contact with the finger, i.e., located outside the thumb or little finger, and are separated from each other. When the ring is worn on the thumb of the left hand, electrode 111 contacts the left thumb, electrode 112 contacts the lower left abdomen, and electrode 113 can contact the second finger of the right hand. A photoplethysmography (PPG) recorder 1730 mounted on the surface in contact with the ring and skin can analyze the light signal and generate an alarm for the user.

To ensure constant wear of the electrocardiogram (ECG) measuring device according to the invention, it can be designed for easy attachment to other objects. Figures 18 and 19 illustrate an example of the ECG measuring device according to the invention, which allows for immediate ECG measurement when connected to trousers. In Figure 18, two clips 111 and 112, serving as two electrodes, are used to attach the ECG measuring device 100 according to the invention to the inside of the trousers, i.e., between the trousers and the user's body. In use, the ECG measuring device 100 is attached to the lower left abdomen of the trousers using clips 111 and 112, and electrodes 113 and the photoplethysmography (PPG) recorder 1830 automatically contact the user's lower left abdomen. When the PPG recorder 1830 sends an alarm or when an ECG measurement is desired, the user touches clip 111 with the fingers of their left hand and clip 112 with the fingers of their right hand.

The electrocardiogram (ECG) measuring device 100 according to the invention, as shown in Figure 19, is attached to the outside of trousers. The ECG measuring device 100 and a clip 113 inside the trousers press against the trousers, and the ECG measuring device 100 is secured to the trousers. When measuring an ECG, the clip 113 automatically contacts the user's lower left abdomen, and the user touches electrode 111 with their left hand fingers and electrode 112 with their right hand fingers.

Figures 20 and 21 illustrate the shape of an electrocardiogram (ECG) measuring device according to the invention coupled to a watch strap using one or two sliding guides serving as electrodes. In Figure 20, the ECG measuring device 100 is secured to the strap when the strap is inserted between the ECG measuring device 100 according to the invention and the sliding guides 112 and 113 serving as electrodes. When the watch is worn on the left wrist, electrodes 111 and the photoplethysmography (PPG) recorder 2030 automatically come into contact with the left wrist. When the PPG recorder 2030 sends an alarm or when an ECG measurement is desired, the user touches the sliding guide 113 with their lower left abdomen and touches the sliding guide 112 with their right fingers.

In Figure 21, the ECG measuring device 100 is secured to the strap when it is inserted between the watch strap and the sliding guide 111 according to the present invention. When the watch is worn on the left wrist, the electrode 111 automatically contacts the left wrist. To measure ECG, the user touches the lower left abdomen to the electrode 113 and the fingers of the right hand to the electrode 112.

As described above, the electrocardiogram (ECG) measuring device according to the invention, with the addition of photoplethysmography (PPG) recorders 1830 and 2030 of Figures 18 and 20, has the advantage of constantly monitoring the user's heart rhythm. For convenience, no separate images have been added, but the ECG measuring device according to the invention can be attached to a watch strap using the clip shown in Figure 18 or 19 instead of the sliding guide shown in Figures 20 and 21.

In an embodiment of the electrocardiogram (ECG) measuring device according to the invention, the ECG measuring device 100 is described as comprising three electrodes; however, other examples of the ECG measuring device according to the invention comprise four electrodes. The operating principle of the ECG measuring device according to the invention comprising said four electrodes is the same as previously described for the case comprising three electrodes. Importantly, the ECG measuring device according to the invention comprising four electrodes consists of three amplifiers that receive ECG signals from the three electrodes, and said three amplifiers amplify one ECG signal; therefore, the device effectively measures three ECG signals simultaneously.

The four-electrode electrocardiogram (ECG) measuring device can be readily implemented based on the foregoing description. The method of using the four-electrode ECG measuring device according to the present invention is almost identical to the method of using the three-electrode ECG measuring device 100 according to the present invention. The three ECG signals measured by the four-electrode ECG measuring device according to the present invention include, for example, two limb leads and one MCL. Alternatively, the three ECG signals can be one limb lead and two MCLs. Figure 22 illustrates an embodiment of the four-electrode ECG measuring device according to the present invention. In Figure 22, the four electrodes 111, 112, 113, and 114 are arranged in pairs on two wide surfaces of a plate-shaped surface.

As described above, the electrocardiogram measuring device according to the present invention has been described in detail, but the present invention is not limited thereto, and the present invention can be modified in various shapes according to the purposes of the present invention.

Industrial utilization potential

The electrocardiogram (ECG) measuring device according to the present invention is portable, can be easily used anytime and anywhere, and can be used as a portable ECG measuring device capable of acquiring ECG information from multiple channels.

Claims (19)

1. An electrocardiogram (ECG) measuring device, comprising: The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively. Two amplifiers, respectively receiving the two electrocardiogram voltages from the first electrode and the second electrode; Electrode drive section for outputting drive voltage; The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part; The first current detector is used to generate an output when two of the three electrodes are in contact with both hands; A second current detector is used to generate an output when one of the remaining electrodes contacts the left leg; An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals. A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and A communication device for transmitting two digital signals. The microcontroller controls the analog-to-digital converter and the communication device, and measures two electrocardiograms when the first current detector and the second current detector generate outputs. 2. The electrocardiogram (ECG) measuring device according to claim 1, characterized in that the ECG measuring device displays six ECG lead signals on a smartphone. 3. The electrocardiogram measuring device according to claim 1, wherein the communication device supports Bluetooth Low Energy. 4. The electrocardiogram measuring device according to claim 1, characterized in that, when multiple electrodes are in contact with a part of the human body, the first current detector causes a microcurrent to flow and detects the microcurrent to generate an output. 5. The electrocardiogram measuring device according to claim 1, wherein when the first current detector generates an output, the microcontroller enters an active mode and begins measuring the electrocardiogram. 6. The electrocardiogram (ECG) measuring device according to claim 1, characterized in that, after a predetermined measurement time has elapsed, the microcontroller terminates the ECG measurement and enters a sleep mode from the activation mode. 7. The electrocardiogram measuring device according to claim 1, wherein the electrocardiogram measuring device is installed in a watch, ring, or elongated flat case. 8. An electrocardiogram (ECG) measuring device, comprising: The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively. Two amplifiers receive two electrocardiogram voltages from the first electrode and the second electrode, respectively; Electrode drive section for outputting drive voltage; The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part; The first current detector is used to generate an output when two of the three electrodes are in contact with both hands; A second current detector is used to generate an output when one of the remaining electrodes contacts the left leg; An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals. A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and A communication device for transmitting the two digital signals. The microcontroller controls the analog-to-digital converter and the communication device, and measures lead I when only the first current detector produces an output. 9. The electrocardiogram measuring device according to claim 8, characterized in that the electrocardiogram measuring device displays six electrocardiogram lead signals on a smartphone. 10. The electrocardiogram measuring device according to claim 8, wherein the communication device supports Bluetooth Low Energy. 11. The electrocardiogram measuring device according to claim 8, characterized in that, when multiple electrodes are in contact with a part of the human body, a first current detector causes a microcurrent to flow and detects the microcurrent to generate an output. 12. The electrocardiogram measuring device according to claim 8, wherein when the first current detector generates an output, the microcontroller enters an active mode and begins measuring the electrocardiogram. 13. The electrocardiogram measuring device according to claim 8, characterized in that, when a predetermined measurement time has elapsed, the microcontroller ends the electrocardiogram measurement and enters a sleep mode from the active mode. 14. The electrocardiogram measuring device according to claim 8, wherein the electrocardiogram measuring device is installed in a watch, ring, or elongated flat case. 15. An electrocardiogram (ECG) measuring device, comprising: The first and second electrodes are used to receive two electrocardiogram voltages from the contacting body parts, respectively. Two amplifiers receive two electrocardiogram voltages from the first electrode and the second electrode, respectively; Electrode drive section for outputting drive voltage; The third electrode is used to receive the output of the electrode driving unit and transmit the output of the electrode driving unit to the contacting body part; An analog-to-digital converter, connected to each of the two amplifiers, is used to convert the output signals of the two amplifiers into two digital signals. A microcontroller is configured to receive two digital signals from the analog-to-digital converter; and A communication device for transmitting the two digital signals. The microcontroller controls the analog-to-digital converter and the communication device, and measures two electrocardiograms when the user touches the 6-lead measurement button (1331) displayed on the smartphone. 16. The electrocardiogram measuring device according to claim 15, wherein the electrocardiogram measuring device displays six electrocardiogram lead signals on a smartphone. 17. The electrocardiogram measuring device according to claim 15, wherein the communication device supports Bluetooth Low Energy. 18. The electrocardiogram measuring device according to claim 15, wherein the microcontroller terminates the electrocardiogram measurement after a predetermined measurement time has elapsed. 19. The electrocardiogram measuring device according to claim 15, wherein the electrocardiogram measuring device is installed in a watch, ring, or elongated flat case.