TW201529041A - Method and system for providing bioimpedance sensor array - Google Patents

Abstract

Exemplary embodiments provide a bioimpedance sensor array for use in fluid flow detection applications, such as heart rate detection. Aspects of the exemplary embodiment include determining an optimal sub-array in a bioimpedance sensor array comprising more than four bioimpedance sensors arranged on a base such that the sensor array straddles or otherwise addresses a blood vessel when worn by a user; passing an electrical signal through at least a first portion of the bioimpedance sensors in the optimal sub-array to the user; measuring one or more bioimpedance values from the electrical signal using a second portion of the bioimpedance sensors in the optimal sub-array; and analyzing at least a fluid bioimpedance contribution from the one or more bioimpedance values.

Description

Bioimpedance sensor array for detecting heart rate efficiency [Reference reference for related applications]

This application is a continuation of the patent application No. 14/103, 717, entitled "Self-Aligning Sensor Array", filed in the United States on December 11, 2013. This application claims patent application No. 61/969,763 entitled "Bioimpedance Square Array Configuration for Heart Rate Detection", filed in the United States on March 24, 2014. The priority of both applications is incorporated herein by reference.

The present invention relates to a bioimpedance sensor array and a method for providing a bioimpedance sensor array.

The heart rate can be measured, for example, by detecting a change in impedance caused by a pulse in the blood flow in a localized region of the human body. Local measurement of heart rate is usually For example, it is performed on the chest, but other parts of the body that contain arteries can also be used for heart rate measurement, such as on the wrist.

Detecting the heart rate via measurement of the electrical properties of the flowing blood can be achieved by measuring the potential generated by the current through the blood, arteries, and surrounding tissue. In an AC power meter, the measured potential will be proportional to the impedance of the area through which the current and current pass. The electrodes are used for this measurement. The electrodes are typically configured in a two-wire configuration where current is passed through and the voltage between the same pair of electrodes is measured. The problem with a two-wire configuration is the introduction of a contact (or lead) resistor that causes the additional resistance term to have an effect on the potential measurement (ie, for DC power measurements, Ohm's law gives V = I*R, where In this case, R = resistance of the sample + resistance of the junction), and can be a substantial portion of the total resistance, and thus the measurement can be blurred, especially in low resistance samples.

A four-wire measurement can be used to overcome the contact resistance problem by passing a current between two dedicated current electrodes and measuring the potential between the two dedicated voltage electrodes, all of which are configured in an in-line configuration. (The current electrode is placed outside the voltage electrode). In a four-wire electrode configuration, the voltage difference between the current electrodes is separated from the voltage measurement itself, thus minimizing its extra action.

In addition to the in-line configuration, the current and voltage electrodes can be configured in a square layout. For film impedance measurements, the four electrodes can be outlined in a square or rectangular shape (ie, each electrode occupies a corner). This configuration is used in the Van der Pauw method of measuring resistivity (or measuring sheet resistance when involving substantially two-dimensional geometries). In one implementation, two current electrodes and two voltage electrodes can be placed at the corners of the square profile, and current can flow along a single edge of the square of the outlined profile. The voltage can then be measured along the edge opposite the edge of the current and used Ohm's law is used to calculate the resistance between the current edge and the voltage edge.

The in-line four-wire bioimpedance measurement (eg, heart rate) on the front side of the user's forearm can be detected using bioelectrical impedance by placing the four electrodes in a column along the radial artery, two voltage electrodes The side is two current electrodes.

However, in a conventional implementation having electrodes placed along the forearm, each of the electrodes is about 0.7 cm ² or greater than 0.7 cm ² such that a fully inline configuration of the electrodes requires up to about 8 cm on the forearm. space. For many applications, the space required by this electrode configuration is, for example, too large, which would limit the type and shape of the device on which the impedance-based heart rate detector can be mounted. For example, if a heart rate detector needs to be placed in a wristwatch type host device, a tighter electrode configuration would be required.

Accordingly, there is a need for bioimpedance measurement devices for use in fluid flow detection applications such as heart rate detection, and bioimpedance methods and host devices using such impedance measurement devices that utilize tight electrodes Configure while maintaining sufficient measurement sensitivity.

The illustrative embodiments provide a bioimpedance sensor array for use in fluid flow detection applications such as heart rate detection. An aspect of an illustrative embodiment includes determining an optimal sub-array in a bio-impedance sensor array comprising four or more bio-impedance sensors, the bio-impedance sensor array on the substrate such that the sensor The array spans or otherwise addresses the blood vessel when worn by the user; transmitting an electrical signal to the user via at least a first portion of the bio-impedance sensor in the optimal sub-array; using the best The second part of the bioimpedance sensor in the array And measuring one or more bioimpedance values from the electrical signal; and analyzing at least the fluid bioimpedance effect from the one or more bioimpedance values.

In accordance with the methods and systems disclosed herein, the illustrative embodiments provide an impedance measuring device that can be used in a wearable device that does not require accurate placement over the wearer's blood vessel.

10A‧‧‧Wearing sensor platform

10B‧‧‧Wearing sensor platform

10'‧‧‧ Wearable Sensor Platform

12A‧‧‧Basic Module

12B‧‧‧Basic Module

14A‧‧‧Sensor Module

14B‧‧‧Sensor Module

14'‧‧‧Sensor Module

16A‧‧‧Strips/Ties

16B‧‧‧Strips/Ties

16'‧‧‧ strips

18A‧‧‧Display/Graphical User Interface (GUI)

18B‧‧‧Display/Graphical User Interface (GUI)

18'‧‧‧ display

20A‧‧‧Basic Computing Unit

20B‧‧‧Basic Computing Unit

22A‧‧‧Battery

22B‧‧‧Battery

24A‧‧‧Sensor unit

24B‧‧‧Sensor unit

24'‧‧‧Sensor unit

26A‧‧‧Sensor board

26B‧‧‧Sensor board

26'‧‧‧Sensor board

28A‧‧‧Sensor calculation unit

28B‧‧‧Sensor calculation unit

28'‧‧‧Sensor calculation unit

30A‧‧‧ buckle

30B‧‧‧ buckle

200‧‧‧Basic Computing Unit

201‧‧‧Battery

202‧‧‧ processor

204‧‧‧Operating System (OS) and Applications

205‧‧‧Communication interface

206‧‧‧ memory

208‧‧‧Input/Output (I/O)

210‧‧‧Communication interface

214‧‧‧ sensor

214A‧‧‧Accelerometer/Gyro

214B‧‧‧ thermometer

220‧‧‧Power Management Unit

222‧‧‧Power interface

308‧‧‧User wrist

310‧‧‧ strips

312‧‧‧Optical sensor array

312A‧‧‧Discrete optical sensor

312B‧‧‧Photodetector

312C‧‧‧Light source

314‧‧‧Skin Electro-Reaction (GSR) Sensor Array

316‧‧‧Bioimpedance (BioZ) sensor array

316'‧‧‧Bioimpedance Sensor

318‧‧‧Electrocardiographic Sensor (ECG)

320‧‧‧ thermometer

Blocks of 400, 402, 404, 406‧‧‧ flowcharts

500‧‧‧Bioimpedance Sensor Array

502, A, B, C, D, E, F, G‧‧ ‧ subarray

504‧‧‧Discrete bioimpedance sensor

510‧‧‧

(1,1), (1,2), (2,1), (2,2) ‧ ‧ index

I‧‧‧ current sensor

LS‧‧‧Photodetector

N‧‧‧Unused sensor

PD‧‧‧ optical sensor

V‧‧‧ voltage sensor

These and/or other features and utilities of the general inventive concept of the present invention will become apparent and more readily apparent from the description of the appended claims.

1A and 1B are diagrams illustrating an embodiment of a modular wearable sensor platform.

2 is a diagram illustrating one embodiment of a modular wearable sensor platform and components including a base module.

3 is a block diagram illustrating an illustrative embodiment of a sensor array system for use in a wearable device such as a modular wearable sensor platform.

4 is a flow diagram illustrating a method of providing a bioimpedance sensor array and a method for using a bioimpedance sensor array to monitor and analyze physiological parameters, such as fluid flow, for use in applications including heart rate detection. Figure.

FIG. 5 is a block diagram depicting an exemplary bioimpedance sensor array.

6A-6D are diagrams illustrating possible configurations of current sensors and voltage sensors in a 2x2 sub-array.

6E illustrates a diagonal sub-array configuration of current sensors and voltage sensors that can be used in a 2x3 bioimpedance sensor.

The embodiments of the present general inventive concept will be described in detail with reference to the accompanying drawings, in which The embodiments are described below in order to explain the general inventive concepts of the invention in the drawings.

Advantages and features of the present invention, as well as methods for achieving the advantages and features of the present invention, may be more readily understood by reference to the accompanying claims. However, the general inventive concept of the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, the embodiments are provided so that this disclosure will be thorough and complete, and the concept of the general inventive concept will be fully conveyed to those skilled in the art, and the general inventive concept of the invention will be The scope of the patent application is defined. In the drawings, the thickness of layers and regions are exaggerated for clarity.

The use of the terms "a", "an" and "the" and "the" Both. Unless otherwise stated, the terms "including", "having", "including" and "including" are understood to mean an open term (ie, meaning "including (but not limited to)".

As used herein, the term "component" or "module" means, but is not limited to, a software or hardware component that performs certain tasks, such as a field programmable gate array (FPGA) or Application specific integrated circuit (ASIC). A component or module may advantageously be configured to reside in an addressable storage medium and configured to operate on one or more processors. Thus, a component or module can contain (as an example) a component, such as Software components, object-oriented software components, category components, and task components, processes, functions, properties, procedures, subroutines, code segments, drivers, firmware, microcode, circuits, Data, databases, data structures, tables, arrays and variables. The functionality provided for components and components or modules may be combined into fewer components and components or modules, or further separated into additional components and components or modules.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning meaning meaning meaning It is to be noted that the use of any and all of the examples or exemplified terms provided herein is intended to clarify the invention and not to limit the scope of the invention. In addition, all terms defined in a common dictionary cannot be over-interpreted unless otherwise defined.

The illustrative embodiments provide a bioimpedance measurement device that can be used in fluid flow detection applications, such as heart rate detection, and describe bioimpedance methods and host devices that use such bioimpedance measurement devices. The bioimpedance sensor array can be configured as an X x Y array having more than four and preferably at least six or eight discrete bioimpedance sensors, including but not limited to electrodes. In one embodiment, at least one pair of electrodes in the bioimpedance sensor array are determined to be current electrodes through which an induced current is passed, and at least another pair of electrodes are selected as voltage electrodes that measure a potential difference or voltage. In one embodiment, the selection or determination of the pair of current and voltage electrodes is fixed. In another embodiment, the selection or determination of the pair of current and voltage electrodes is dynamic such that the bioimpedance sensor array can be scanned to determine which of the current and voltage electrodes to provide the best signal quality.

The bioimpedance measuring device can be used in an electronic device using a bioimpedance measuring device. Such electronic devices may include, but are not limited to, wearable devices as well as other portable and non-portable computing devices such as wristwatches, cellular phones, smart phones, tablets, and laptops.

1A and 1B are diagrams illustrating an embodiment of a modular wearable sensor platform. FIG. 1A depicts a perspective view of one embodiment of a wearable sensor platform 10A, while FIG. 1B depicts an exploded view of another embodiment of a wearable sensor platform 10B. While the components of the wearable sensor platforms 10A and 10B (collectively the wearable sensor platform 10) may be substantially identical, the locations of the modules and/or components may vary. In the discussion of the exact details of Figures 1A and 1B, alphanumeric indications (e.g., 10A and 10B) are used. However, for reference to any one or both of the embodiments depicted in Figures 1A and 1 B, a numerical indication (e.g., 10 for 10A and/or 10B) is used.

In the embodiment illustrated in FIG. 1A, the wearable sensor platform 10A can be implemented as a smart wristwatch or other computing device that fits over the wrist of the user. The wearable sensor platform 10A can include a base module 12A, a strip 16A, a buckle 30A, a battery 22A, and a sensor module 14A coupled to the strip 16A. In some embodiments, the modules and/or components of the wearable sensor platform 10A can be removed by the end user. However, in other embodiments, the modules and/or components of the wearable sensor platform 10A are integrated into the wearable sensor platform 10A by the manufacturer and may not be intended to be removed by the end user.

The sensor module 14A can be positioned within the strip 16A such that the sensor module 14A is located at the bottom of the user's wrist that is in contact with the user's skin to collect physiological data from the user. The base module 12A is attached to the strap 16A such that the base module 12A is positioned on the top of the wrist.

The base module 12A can include a base computing unit 20A, and a display 18A on which a graphical user interface (GUI) can be provided. The base module 12A performs functions including, but not limited to, displaying time, performing calculations, and/or displaying data including sensor data collected by the sensor module 14A. In addition to communicating with the sensor module 14A, the base module 12A can also wirelessly communicate with other sensor modules (not shown) that are worn on different body parts of the user to form a body area network. As will be more fully discussed with respect to FIG. 2, basic computing unit 20A can include a processor, a memory, a communication interface, and a set of sensors, such as an accelerometer and a thermometer.

The sensor module 14A collects physiological data, activity data, sleep statistics, and/or other data from the user, and communicates with the basic module 12A. The sensor module 14A includes a sensor unit 24 housed in the sensor board 26A. The sensor unit 24A may include an optical sensor array, a thermometer, a galvanic skin response (GSR) sensor array, a bio-impedance (BioZ) sensor array, and an electrocardiography sensor (ECG). Sensor, or any combination thereof. Other sensors can also be used.

The sensor module 14A can also include a sensor calculation unit 28A. The sensor calculation unit 28A can analyze the data collected by the sensor unit 24A, perform calculations on the data, and store the data in some embodiments. The data from the sensor unit 24A can also be provided to the basic computing unit 20A for further processing. Since the sensor computing unit 28A can be integrated into the sensor board 26A, the sensor computing unit is illustrated by dashed lines in FIG. 1A. In other embodiments, the sensor computing unit 28A can be omitted. In this embodiment, the basic computing unit 20A may perform functions that would otherwise be performed by the sensor computing unit 28A. Via sensor module 14A and The combination of the basic modules 12A collects, stores, analyzes and presents the data to the user.

The wearable sensor platform 10B depicted in FIG. 1B is similar to the wearable sensor platform 10A depicted in FIG. 1A. Therefore, the wearable sensor platform 10B includes a strip 16B, a battery 22B, a buckle 30B, a basic module 12B including a display/GUI 18B and a basic computing unit 20B, and a sensor unit 24B and a sensor board 26B. And a sensor module 14B of the optional sensor computing unit 28B, which is similar to the strip 16A, the battery 22A, the buckle 30A, the basic module 12A including the display/GUI 18A and the basic computing unit 20A, and includes The sensor unit 24A, the sensor board 26A, and the sensor module 14A of the optional sensor computing unit 28A. However, as can be seen in Figure 1B, the location of some of the modules has changed. For example, buckle 30B is closer to display/GUI 18B than buckle 30A. Similarly, battery 22B is housed by base module 12B. In the embodiment depicted in FIG. 1A, battery 22A is received by strip 16A opposite display 18A. Thus, in various embodiments, the position and/or function of the module can be changed.

In the two embodiments illustrated in Figures 1A and 1B, the strap or strap 16 can be a piece or module. The strip 16 can be made of fabric. For example, a wide range of twistable and expandable elastic mesh/textiles are contemplated. Strip 16 can also be configured as multiple strips or as a modular link configuration. In some implementations, the strap 16 can include a latch or snap mechanism to retain the strap on the user. In some embodiments, the strip 16 will include a connection to the base module 12 and the sensor module 14 plus other wiring (not shown). Individual wireless communication or wireless communication in conjunction with the wiring between the base module 12 and the sensor module 14 is also contemplated.

2 is a diagram showing a modular wearable sensor platform 10' and including a basic mode A diagram of one embodiment of a group of components. The wearable sensor platform 10' is similar to the wearable sensor platform 10 and thus contains similar components with similar indicia. In this embodiment, the wearable sensor platform 10' can include a strap 16' and a sensor module 14' attached to the strap 16'. The snubber sensor module 14' may further include a sensor board 26' attached to the strip 16', and a sensor unit 24' attached to the sensor board 26'. The sensor module 14' can also include a sensor computing unit 28'.

The wearable sensor platform 10' includes a basic computing unit 200 similar to the basic computing unit 20, and one or more batteries 201. For example, a permanent and/or removable battery similar to battery 22 can be provided. In one embodiment, the basic computing unit 200 can communicate with the sensor computing unit 28' via the communication interface 205. In one embodiment, communication interface 205 can include a serial interface. The basic computing unit 200 can include a processor 202, a memory 206, an input/output unit (I/O) 208, a display 18', a communication interface 210, a sensor 214, and a power management unit 220.

Processor 202, memory 206, I/O 208, communication interface 210, and sensor 214 can be coupled together via a system bus (not shown). Processor 202 can include a single processor having one or more cores, or multiple processors having one or more cores. The processor 202 can run an operating system (OS) and various applications 204. Examples of OS may include, but are not limited to, Linux and ^AndroidTM .

According to an exemplary embodiment, processor 202 may run a calibration and data acquisition component (not shown) that may perform sensor calibration and data acquisition functions. In one embodiment, the sensor calibration function can include a program for self-aligning one or more sensor arrays with blood vessels. In one embodiment, sensor calibration may be performed at periodic intervals, either at startup, before receiving data from the sensor, or during operation.

The memory 206 can include one or more memories including different memory types including, for example, DRAM, SRAM, ROM, cache memory, virtual memory, and flash memory. I/O 208 can include a collection of components that input information and output information. Example components including I/O 208 include a microphone and a speaker.

Communication interface 210 can include a wireless network interface controller (or similar component) for wireless communication over a network. In one embodiment, an example type of wireless communication may include Bluetooth Low Energy (BLE) and WLAN (Wireless Local Area Network). However, in another embodiment, an example type of wireless communication may include a WAN (Wide Area Network) interface, or a cellular network, such as 3G, 4G, or LTE (Long Term Evolution).

In one embodiment, display 18' may be integrated with basic computing unit 200, while in another embodiment, display 18' may be external to basic computing unit 200. For example, sensor 214 can include any type of microelectromechanical system (MEMs) sensor, such as accelerometer/gyroscope 214A and thermometer 214B.

The power management unit 220 can be coupled to one or more batteries 201 and can include a microcontroller that governs the power functions of the basic computing unit 200. In one embodiment, the power management unit 220 can also control the supply of battery power via the power interface 222 to the snubber sensor module 14'.

Although not shown in the drawings, depending on the type of sensor unit 24 that is provided on the sensor module 14, the basic computing unit 200 may optionally include an electrocardiogram sensor (ECG) and a bioimpedance (BIOZ) analog front end. (analog front end; AFE), galvanic skin response (GSR) AFE, and optical sensor AFE.

3 is a block diagram illustrating an illustrative embodiment of a sensor array system for use in a wearable device such as a modular wearable sensor platform. The system contains A strip 310 of one or more self-aligned sensor arrays is housed. In one embodiment, the strip 310 corresponds to the strip 16 of the modular wearable sensor platform 10 (with or without the sensor board 26). In another embodiment, the strip 310 can be a single device that is not part of the modular wearable sensor platform 10.

The top portion of Figure 3 shows the strip 310 wrapped around the cross-section of the user's wrist 308, while the bottom portion of Figure 3 shows the strip 310 in the unwound position. According to one embodiment, strip 310 includes a bio-impedance (BioZ) sensor array 316, and optionally an optical sensor array 312, a galvanic skin response (GSR) sensor array 314, an electrocardiogram sensor (ECG), 318 or any combination thereof.

According to an exemplary embodiment, the sensor arrays 316, 314, and 312 each include a discrete sensor array disposed or disposed on the strip 310 such that when the strip 310 is worn over a body part, each sensor The array spans or otherwise localizes a particular blood vessel (ie, a vein, artery, or capillaries) or an area with a higher electrical response regardless of the blood vessel. More specifically, each of the sensor arrays 316, 314, and 312 can be disposed substantially perpendicular to the longitudinal axis of the blood vessel and overlap the vessel width to obtain an optimal signal. In one embodiment, the strips 310 can be worn such that the self-aligned sensor arrays 316, 314, and 312 on the strip 310 contact the skin of the user, but are not tight enough to prevent the strip 310 from being in the body part (such as The extent to which any movement is made above the user's wrist 308).

As used herein, bio-impedance (BioZ) sensor array 316 includes impedance measurement devices that can be used in fluid flow detection applications of living organisms, such as heart rate detection. The BioZ sensor array 316 and bioimpedance method can be used in conjunction with host electronics including, but not limited to, the basic computing unit 200. Other examples of host electronics include, but are not limited to, other types of wearables And portable and non-portable computing devices, such as cellular phones, smart phones, tablets, and laptops.

Conventional bioimpedance sensors typically include a single counter electrode that measures bioelectrical impedance or flow opposite to the flow of current through the tissue: one for the "I" current and the other for the "V" voltage.

However, according to one embodiment, a bio-impedance sensor array 316 is provided that includes more than four bio-impedance sensors 316' and that spans the user's blood vessel when worn. In one embodiment, any pair of bio-impedance sensors 360' can be selected to form a current pair "I" and another pair can be selected to form a voltage pair "V", and as explained below. In one embodiment, the selection is fixed. In another embodiment, the selection is dynamic and performed during operation of the bio-impedance sensor array 316. A multiplexer (not shown) can be used for dynamic selection. In the illustrated embodiment, bioimpedance sensor array 316 is depicted as spanning an artery, such as a radial artery or a ulnar artery. In one embodiment, one or more of the BioZ sensors 316' can be multiplexed with one or more of the GSR sensors 314.

In one embodiment, optical sensor array 312 can include a photoplethysmograph (PPG) sensor array that can measure relative blood flow, pulse, and/or blood oxygen concentration. In this embodiment, optical sensor array 312 can be disposed on strip 310 such that optical sensor array 312 spans or otherwise localizes an artery, such as a radial artery or a ulnar artery. In one embodiment, optical sensor array 312 can include an array of discrete optical sensors 312A, wherein each discrete optical sensor 312A is positioned adjacent to at least one photodetector 12B and adjacent to photodetector 312B. A combination of at least two matching light sources 312C. In one embodiment, each of the discrete optical sensors 312A can be adjacent to the strip 310 The optical sensor separates a predetermined distance of approximately .5 to 2 mm.

In one embodiment, the light sources 12C can each comprise a light emitting diode (LED), wherein the LEDs in each of the discrete optical sensors 312A emit light having different wavelengths. Example light colors emitted by LEDs can include green, red, near infrared, and infrared wavelengths. Each of the photodetectors 312B converts the received light energy into an electrical signal. In one embodiment, the signal can include a reflected light plethysmograph signal. In another embodiment, the signal can include a transmitted light plethysmograph signal. In one embodiment, photodetector 312B can include a photonic crystal. In an alternate embodiment, photodetector 312B can include a charge-coupled device (CCD).

The galvanic skin response (GSR) sensor array 314 can include four or more GSR sensors that can measure the electrical conductivity of the skin as the moisture content changes. Conventionally, two GSR sensors are necessary to measure the electrical resistance along the surface of the skin. According to one aspect of an embodiment, the GSR sensor array 314 is depicted as including four GSR sensors, of which any two of the four sensors can be selected for use. In one embodiment, the GSR sensor 314 can be spaced 2 to 5 millimeters apart on the strip.

In yet another embodiment, the strip 310 can include one or more electrocardiographic sensors (ECG) 318 (one sensor on the skin-facing interior of the strip and another sensor outside the strip) It measures the electrical activity of the user's heart over a period of time. Additionally, strip 310 may also include a thermometer 320 for measuring temperature or temperature gradients.

4 is a flow diagram illustrating a method of providing a bioimpedance sensor array and a method for using a bioimpedance sensor array to monitor and analyze physiological parameters, such as fluid flow, for use in applications including heart rate detection. Figure. In one implementation In one example, the program can be executed by one or more software components (eg, calibration and data acquisition components) running on a processor coupled to the sensor array. The processor may correspond to the sensor computing unit 28, the processor 202 of the basic computing unit 200 (shown in Figure 2), and/or a separate processor.

According to an exemplary embodiment, the program may begin by determining an optimal sub-array in a bio-impedance sensor array comprising four or more bio-impedance sensors, the bio-impedance sensor array being disposed on a substrate The bioimpedance sensor array is caused to span or otherwise address the blood vessel (block 400) when worn by the user. In one embodiment, the optimal sub-array may include any pair of bio-impedance sensors selected to form a current pair "I", and another pair of bio-impedance sensors selected to form a voltage pair "V" .

FIG. 5 is a block diagram depicting an exemplary bioimpedance sensor array. According to one embodiment, the bio-impedance sensor array 500 can be configured as an X x Y array having more than four and preferably at least six or eight discrete bio-impedance sensors 504. The X x Y bio-impedance sensor array 500 can be placed at any suitable measurement site. Where heart rate measurement is used as an example, the sensor can be placed on the underside of the wearer's forearm (ie, on the palm side) or on another body part. The position of the sensor array on the underside of the forearm can be further improved to a position above the artery (such as the radial or ulnar artery), wherein the sensor positioned relative to the artery can cause the artery to be located by bioimpedance sensing Anywhere within the area defined by array 500, as long as the blood pulse travels between the pair of current sensors and the voltage sensor. In the illustrated embodiment, the bioimpedance sensor array 500 is illustrated as being positioned over both the ulnar artery and the iliac artery. However, in another embodiment, the bioimpedance sensor array 500 can be placed over only one of the arteries or over other blood vessels.

According to one aspect of the exemplary embodiment, at least one M x N sub-array 502A-502G (collectively sub-array 502) of the X x Y bio-impedance sensor array 500 is selected as the best sub-array. In this embodiment, the optimal sub-array of the bioimpedance sensor refers to a particular set of discrete bio-impedance sensors 504 that have an optimal position above the blood vessel and thus provide optimal signal quality.

In one embodiment, at least one pair of bio-impedance sensors in the optimal sub-array 502 are selected as current sensors, and at least another pair of bio-impedance sensors are selected as voltage sensors. In addition, the additional bio-impedance sensor 504 in the bio-impedance sensor array 500 can be selected as a current or voltage sensor, or not used. In one embodiment, the selection of the current sensor and voltage sensor does not necessarily require selection of a bio-impedance sensor in an adjacent column or row of the bio-impedance sensor array.

As shown in FIG. 5, one possible configuration of the M x N sub-array 502 can include a 2 x 2 square sensor configuration. In one embodiment, adjacent M x N sub-arrays 502 are electrically joined together to form a complete X x Y bio-impedance sensor 500. In the illustrated example, four 2x2 sub-arrays 502 are shown placed adjacent to each other in a column to form a single 2x8 bio-impedance sensor array 500.

In one embodiment, the configuration and placement of sub-array 502 is fixed, wherein each of sub-arrays 502 includes at least two current sensors and at least two voltage sensors. For example, sub-arrays A, C, E, and G can be fixed, and during operation, one of the sub-arrays is selected as the best sub-array.

In another embodiment, the configuration of sub-array 502 is dynamic. In this embodiment, during calibration, the bioimpedance sensor array 500 is scanned to identify which bioimpedance sensor set provides the best signal and uses the identified bioimpedance The sensor set is the best subarray. In one embodiment, during this procedure, the discrete bio-impedance sensor 504 can be activated in series. In an alternate embodiment, the discrete bio-impedance sensor 504 can be activated in parallel. Thereafter, a first portion of the bioimpedance sensor in the optimal sub-array providing the best signal is selected as the current sensor, and the second portion of the bio-impedance sensor in the optimal sub-array is selected as the voltage sense Detector. For example, in FIG. 5, any of A through G of sub-array 502 can be determined to be the best sub-array. Other subarrays are also possible but are not described. Also, after a predetermined period of time or at regular time intervals, the determination of the best sub-array can be performed again to see if there is a better setting to improve performance.

6A-6D are diagrams illustrating possible configurations of current sensors and voltage sensors in a 2x2 sub-array. For purposes of explanation, FIG. 6A illustrates the illustrated example assuming that the 2×2 sub-array is in columns (x) with indices (1, 1), (1, 2), (2, 1), and (2, 2) and Line (y) format.

6A shows the configuration of the current sensor "I" and the voltage sensor "V" in the 2×2 sub-array as: (1, 1)=I, (1, 2)=V, (2, 1) = V, and (2, 2) = I.

6B illustrates the configuration of the current sensor "I" and the voltage sensor "V" in the 2×2 sub-array as: (1, 1)=I, (1, 2)=V, (2, 1) = I, and (2, 2) = V.

6C shows the configuration of the current sensor "I" and the voltage sensor "V" in the 2×2 sub-array as: (1, 1)=V, (1, 2)=I, (2, 1) = V, and (2, 2) = I.

6D shows the configuration of the current sensor "I" and the voltage sensor "V" in the 2×2 sub-array as: (1, 1)=V, (1, 2)=I, (2, 1) = I, and (2, 2) = V.

6E illustrates a diagonal subarray configuration of current sensors and voltage sensors that can be used, for example, in a 2x3 bioimpedance sensor, where N represents unused in six sensor arrays. Sensor. As shown, the proximity in the first column of the array The voltage and current sensors ("V", "I") are offset by one line from the adjacent current and voltage sensors ("I", "V") in the second column of the array.

Where a heart rate measurement on the wrist is used as an example, the optimal sub-array may be located above the radial or ulnar artery, wherein positioning of the sub-array relative to the artery may allow any artery to be located in the region defined by the optimal sub-array Anywhere within the fluid, as long as the fluid (eg, blood) pulse travels between the pair of current sensors and the voltage sensor. However, placement of the optimal sub-array relative to the brachial artery and/or ulnar artery may not necessarily require the radial artery and/or ulnar artery to be directly between the bioimpedance sensors 500 in the optimal sub-array. However, as long as the outer periphery of the optimal sub-array substantially covers the radial artery and/or the ulnar artery (or other blood vessel), measurements suitable for inferring the heart rate can still be obtained.

Those skilled in the art will readily recognize that additional sensors can be configured using additional sensors and/or in a variety of array type configurations to form different shapes and effectively increase the sensing area covered by the sensor array, thus Allowing greater placement robustness of the sensor device, as long as at least one of the sub-arrays overlaps the blood vessel.

In one embodiment, each of the bioimpedance sensors 504 can include an electrode. The electrodes can be, for example, in the range of about 0.1 to 1.0 cm ² and, for example, separated by a distance of about 0.1 to 1.0 cm. The electrode size is proportional to the required placement distance between the electrodes, so the smaller electrodes should be placed closer together. The electrodes can be constructed from several electrically conductive materials. In one embodiment, the electrode material can include at least one of: a metal material, compound, or alloy comprising gold, stainless steel, nickel, and other metallic elements. In another embodiment, the electrode material can include a coating on a non-conductive material, such as a polymer or ceramic coated with silver/silver chloride (Ag/AgCl). However, additional conductor/non-conductor material combinations (eg, additional precious metal and metal halide combinations) can be used. In another embodiment, a combination of materials can be used, including, for example, a conductive rubber having an Ag/AgCl coating.

Referring again to FIG. 4, the processor can be configured to communicate an electrical signal to the user (block 402) via at least a first portion of the bio-impedance sensor in the optimal sub-array.

In one embodiment, the one or more electrical signals can include a current that passes between the two current sensors. The electrical signal should preferably intersect the path of the fluid flow to be measured. In an embodiment, the electrical signals may be modified, if necessary, by adjusting electrical signal parameters to provide an optimal measurement, the electrical signal parameters including frequency, amplitude, waveform, or any combination thereof. In one embodiment, the electrical signal parameters may change in response to the quality of any of the sensed signals. According to one embodiment, the sensing method may further comprise performing a series of measurements by different electrical signal parameters, and the sensed signals may be compared to select an optimal measurement.

Still referring to FIG. 4, one or more bioimpedance values are measured from the electrical signal using a second portion of the bioimpedance sensor in the optimal sub-array (block 404). In one embodiment, the bioimpedance value can be measured by sensing a potential or voltage between two voltage sensors/electrodes in the bioimpedance sensor array. In one embodiment, this induction of potential preferably intersects the path of the fluid flow to be measured. In yet another embodiment, bioimpedance values from adjacent electrodes can be measured.

Finally, at least the fluid bioimpedance effect is measured from one or more bioimpedance values (block 406). The positively measured fluid bioimpedance can comprise a variety of fluid types including, for example, fluids flowing in the body such as blood flowing through the artery.

Methods and systems for providing bio-impedance sensor arrays for heart rate detection have been disclosed. The invention has been described in terms of the illustrated embodiments, and There may be variations to the embodiments, and any variations are within the spirit and scope of the invention. For example, an embodiment may be implemented using hardware, software, a computer readable medium containing program instructions, or a combination thereof. Software written in accordance with the present invention will be stored in some form of computer readable medium, such as a memory, hard drive or CD/DVD-ROM, and will be executed by the processor. Therefore, many modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

Blocks of 400, 402, 404, 406‧‧‧ flowcharts

Claims (30)

A method for providing a bio-impedance sensor array, comprising: determining an optimal sub-array in a bio-impedance sensor array comprising four or more bio-impedance sensors, the bio-impedance sensor array being configured Having the sensor array straddle or otherwise address a blood vessel when worn by a user; transmitting an electrical signal to at least a first portion of the bioimpedance sensor in the optimal sub-array Using the second portion of the bioimpedance sensor in the optimal sub-array to measure one or more bioimpedance values from the electrical signal; and from the one or more bioimpedance values Analyze at least the fluid bioimpedance effect. The method of claim 1, further comprising: selecting at least one pair of the bio-impedance sensors of the optimal sub-array to form a current sensor, and selecting at least another pair of bio-impedances A sensor to form a voltage sensor. The method of claim 1, wherein the configuration and placement of the optimal sub-array is fixed. The method of claim 1, wherein the configuration and placement of the optimal sub-array is dynamic. The method of claim 4, further comprising: scanning the bioimpedance sensor array to identify which bioimpedance sensor set provides an optimal current signal, and using the identified bioimpedance a sensor set as the optimal sub-array; selecting a first portion of the bio-impedance sensor in the optimal sub-array that provides an optimal current signal as a current sensor; and selecting the best sub- A second portion of the bioimpedance sensor in the array acts as a voltage sensor. The method of claim 5, wherein the optimal sub-array is positioned relative to the blood vessel such that the blood vessel is located anywhere within the region defined by the optimal sub-array, as long as the blood pulse It suffices to travel between the pair of current sensors and the voltage sensor. The method of claim 1, further comprising: multiplexing one or more of the bioimpedance sensors with one or more galvanic skin sensors. The method of claim 1, wherein the bioimpedance sensor comprises an electrode. The method of claim 8, wherein the size of the electrode is proportional to a desired placement distance between the electrodes such that the smaller electrodes are placed closer together. The method of claim 8, wherein the electrode is in a size range of about 0.1 to 1.0 cm ² and is separated by a distance of about 0.1 to 1.0 cm. The method of claim 8, wherein the electrode comprises at least one of a metal material, a compound or an alloy comprising gold, stainless steel, nickel, and other metal elements. The method of claim 8, wherein the electrode comprises a polymer or ceramic coated with silver/silver chloride. The method of claim 8, wherein the electrode comprises a conductive rubber having a silver/silver chloride coating. The method of claim 1, wherein the transmitting the electrical signal further comprises: modifying the electrical signal by adjusting a signal parameter to provide an optimal measurement, The signal parameters include frequency, amplitude, waveform, or any combination thereof. The method of claim 14, further comprising: performing a series of measurements using different signal parameters. A bioimpedance sensor array comprising: an array having four or more bioimpedance sensors disposed on a substrate such that the sensor array spans or otherwise addresses blood vessels when worn by a user; And a processor coupled to the sensor array, the processor configured to: determine an optimal sub-array in the bio-impedance sensor array; via the optimal sub-array At least a first portion of the bio-impedance sensor transmits an electrical signal to the user; using a second portion of the bio-impedance sensor in the optimal sub-array from the electrical signal measurement One or more bioimpedance values; and analyzing at least the fluid bioimpedance effect from the one or more bioimpedance values. The system of claim 16, further comprising: selecting at least one pair of the bio-impedance sensors of the optimal sub-array to form a current sensor, and selecting at least another pair of bio-impedances A sensor to form a voltage sensor. The system of claim 16, wherein the configuration and placement of the sub-array is fixed. The system of claim 18, wherein the configuration and placement of the sub-array is dynamic. The system of claim 19, wherein the processor sweeps Depicting the bioimpedance sensor array to identify which bioimpedance sensor set provides an optimal current signal, and using the identified set of bioimpedance sensors as the optimal subarray; and selecting the The second portion of the bioimpedance sensor in the optimal sub-array acts as a voltage sensor. The system of claim 20, wherein the optimal sub-array is positioned relative to the blood vessel such that the blood vessel is located anywhere within the region defined by the optimal sub-array, as long as the blood pulse It suffices to travel between the pair of current sensors and the voltage sensor. The system of claim 16, wherein one or more of the bioimpedance sensors are multiplexed with one or more galvanic skin sensors. The system of claim 16, wherein the bioimpedance sensor comprises an electrode. The system of claim 23, wherein the size of the electrode is proportional to a desired placement distance between the electrodes such that the smaller electrodes are placed closer together. The system of claim 23, wherein the electrode is in the range of about 0.1 to 1.0 cm ² and is separated by a distance of about 0.1 to 1.0 cm. The system of claim 23, wherein the electrode comprises at least one of: a metal material, compound or alloy comprising gold, stainless steel, nickel, and other metallic elements. The system of claim 23, wherein the electrode comprises a polymer or ceramic coated with silver/silver chloride. The system of claim 23, wherein the electrode comprises Conductive rubber with silver/silver chloride coating. The system of claim 16, wherein the electrical signal is modified to provide an optimal measurement by adjusting a signal parameter comprising a frequency, an amplitude, a waveform, or any combination thereof. The system of claim 29, wherein the series of measurements are performed using different signal parameters.