Patent ID: 12186057

DETAILED DESCRIPTION

As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely examples and that the devices and methods described herein can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the disclosed subject matter in virtually any appropriately detailed structure and function. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description. Additionally, unless otherwise specifically expressed or clearly understood from the context of use, a term as used herein describes the singular and/or the plural of that term.

The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and “having,” as used herein, are defined as comprising i.e., open language. The term “coupled,” as used herein, is defined as “connected,” although not necessarily directly, and not necessarily mechanically.

It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

Reference in the specification to “one embodiment” or “an embodiment” of the present principles, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present principles. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment.

With reference toFIG.1there is shown a ring-shaped wearable device1incorporating apparatus for detecting and recording physiological data. The device is sized to fit over and be retained on the digit of the hand or foot a person whose physiological data is to be captured.

The body of the device may be comprised of metal, plastic or any other material or combination of materials able to provide a suitable support. The choice of materials will depend on the expected purpose and/or the desired aesthetic of the device. For example, in one embodiment the device may be metallic in order to resemble a traditional wedding band. Alternatively, the body of the device may be comprised from an elastic material to allow the device to stretch over a digit or other body part, e.g. around the torso and be retained securely thereto.

Alternatively, device may be adapted to collect physiological data from other types of mammals—e.g. one or more of other primates, equines, canines, felines and bovines—in which case the device will be sized and shaped to be appropriate to the body part it will be retained against.

The device1comprises multiple light emitting diode (LEDs) devices2A-2D that are spaced circumferentially about the inner facing side of the device to irradiate the tissue of the digit from all sides.

The example illustrates four LED devices2though the number may be as few as two or more than four.

Each LED device2comprises multiple LED elements3, each element adapted to emit light within a different non-overlapping band within the infrared and/or visible spectrum, e.g. 400 nm-2600 nm. In the present example each LED device2comprises three LED elements3to emit light in three different non-overlapping bands within the 400 nm-2600 nm range

The following example wavelengths suitable for identifying a variety of different physiological variables:Optical Based Non-invasive Glucose Monitoring Sensor Prototype; Shyqyri Haxha; IEEE Volume 8, Number 6, December 2016;A Novel Art of Continuous Non-invasive Blood Pressure Measurement; Jürgen Fortin NATURE COMMUNICATIONS (2021) 12:1387 https://doi.org/10.1038/s41467-021-21271-8.Pulse Oximetry Optical Sensor Using Oxygen Bound Haemoglobin Z. J. V Cohen, Vol. 24, No. 9; OPTICS EXPRESS 10115 2 May 2016Continuous Non-invasive Hemoglobin Monitoring: The Standard Of Care And Future Impact; Gerald J. Kost Crit Care Med. 2011 October; 39 (10): 2369-2371. doi: 10.1097/CCM.0b013e3182266013A precise non-invasive blood glucose measurement system using NIR spectroscopy and Huber's regression model. Jain, P.; Maddila, R.; Joshi, A. M. Opt. Quantum Electron. 2019, 51, 51.

The device1also comprises multiple photo diode light detectors (PDs)4A-4D spaced circumferentially about the ring. Their detecting apertures are arranged to face inwards towards the digit to detect light emitted from the LEDs2that has transmitted and/or reflected from the tissue of the digit.

With reference also toFIG.2, in addition to the LEDs2and PDs4, the apparatus also includes control and processing circuitry5which includes LED driver circuitry6, a multiplexer7, electrical filter8, amplifier9, analogue to digital converter (ADC)10, and a processor11.

Optionally, the device1may also include a user interface (not shown), e.g. one or more outward facing LEDs, to communicate an operating state of the device to the wearer and/or error codes.

The processor11comprises one or more processors communicatively coupled with computer readable memory adapted to run software to implement the functions of: a control unit12, intensity meter13, pattern detector14, pattern optimizer15including a pattern score generator15A, and a store16.

The store holds minimum and maximum absolute intensity values for different physiological data types; sub range parameters associated with different pattern quality scores for each different physiological data type; and a library of pattern parameters for different physiological signals.

The apparatus is configured to operate according to the algorithm described with reference toFIG.3.

The system is initialized (100). The control unit12selects a first physiological signal type to be measured and recorded from a selection of measurable physiological signals. (101).

Information associated with the first physiological data type is retrieved from the store16(102). The information includes, wavelength, absolute intensity range values; pattern data; and sub-range data associated with pattern quality scores.

The control unit12controls the LED driver6to switch on a first LED element3of first LED device2A to illuminate the tissue of the wearer's finger (103).

Light from the LED element2A is partially transmitted and reflected by the tissue of the digit. Portions of said transmitted or reflected light are received at one or more (possibly all) of the photodiodes4. As the light received at each photodiode4has a different path through the digit, the absolute value of the signal at each photodiode4will differ.

Additionally, because of the different paths, the light received at certain photodiodes may carry a stronger and/or better-quality representation of the selected physiological data than others. This may change over time, for example as a result of relative movement between the device1and the digit.

The control unit12operates the mux7to select one photodiode4A of the multiple photodiodes4from which to receive an output signal (104).

The output signal from the selected photodiode4A is received by the intensity meter13which outputs, to the control unit12, an absolute intensity value indicative of the absolute intensity of light received at the photodiode.

The control unit12is adapted to receive the absolute intensity value, compare this with the absolute intensity value range retrieved from the store16for the selected physiological data type, and in response control the LED driver6to control, i.e. alter where necessary, the intensity of light emitted by the first LED element3of the first LED device2A, until the absolute intensity value as determined by the intensity meter13, falls within the absolute intensity value range (105).

The absolute intensity value is likely to fluctuate, in part because it may include a modulating component attributable to the physiological signal, though this is only likely to cause small fluctuations, but also because of noise, e.g. attributed to the output characteristics of the LED itself but also environmental factors, e.g. because of movement of the wearer, changes in ambient light, temperature. As such the control unit12may be adapted to alter the intensity of the LED2based on an average absolute intensity value.

The output from the mux7is also inputted to a band pass filter8that removes the constant (DC) component of the output signal (106) from the selected photodiode4to leave the varying component indicative of the physiological signals to be measured (108). The variable component output is amplified by amplifier9before being digitized by ADC10and inputted to the pattern detector14(107).

The pattern detector14is adapted to carry out signal processing on the digitized signal received from ADC10to identify the presence of physiological signals of the type selected at101. The output of the pattern detector14may be a portion of the signal that matches or contains a pattern conforming to the selected physiological data or an indicator that no pattern has been detected.

The output from the pattern detector14is received by the pattern optimizer15which performs an optimization algorithm as described below, with reference toFIG.4, to vary the intensity of the LED element3to find a pattern or optimize the quality of an identified pattern (109).

Once a pattern that meets the quality threshold is identified, a sample of the pattern is recorded in store16and/or may be transmitted, e.g. wirelessly, to a remote system. (110)

If illumination with a second wavelength is required to obtain further patterns for the selected physiological data type, the control unit12controls the LED driver6to operate the second LED element3B of the first LED device2A to illuminate the tissue of the wearer's finger with the second wavelength and steps105-110repeated (111).

If applicable, step111may be repeated to operate third element3C, for a third wavelength.

Thereafter, the control unit12operates the mux7to select the second photodiode receiver4B. Steps105-111are repeated to capture physiological signals from the output signals of the second photodiode receiver4B. This is repeated for each of the photodiodes4D.

With reference toFIG.4, the pattern detector14carries out one or more signal processing steps, e.g. cross correlation and/or fast Fourier transform to determine the presence of a signal within the output from the ADC10that matches one or patterns held in the store16that correspond to those having a known association with the selected physiological data type.

With reference to the process illustrated on the right-hand side ofFIG.4, if no pattern is detected by the pattern detector14, a ‘no pattern’ signal is transmitted to the intensity range controller12A. In response, if the controller12is set in an ‘increase intensity state’ and the absolute intensity value of the output signal is not at a maximum value within the range, the controller12A controls the LED driver circuitry6to increase the intensity of the LED3until the absolute signal value increases by an incremental amount and awaits for a further ‘no pattern’ signal from the pattern detector14. This is repeated until the maximum intensity within the range is reached or a pattern is detected. If the maximum absolute intensity value is reached and still no pattern is detected, the control unit12A switches to a ‘decreasing intensity state’ and decreases the absolute intensity value to a set increment below the initial intensity value, and then further decreases the absolute value by the increment until the minimum absolute intensity value of a pattern is reached.

If no pattern is found, the controller unit12operates the mux7to switch to a different photodiode4.

Note that this process assumes that the initial absolute intensity value lies between the max and min values for that range. If the initial absolute value is at the min or max value then only an increasing or decreasing incrementation process needs to be used.

With reference to the left-hand process flow inFIG.4, if a pattern is found, characteristics of the output signal that are determined to match the pattern are passed to the pattern score generator15A which determines from this input, a pattern quality score.

The optimizer15determines whether the pattern score outputted from the pattern score generator15A meets a threshold quality score. If yes, then the output signal from the ADC10is captured, e.g. passed to and recorded in the store16.

If the pattern quality score does not meet the threshold, the optimizer15sets a sub-range of absolute intensity values centered on the current absolute intensity value and having a breadth that is based on the pattern score. The optimizer also sets an interval size for changes in the absolute intensity value within the sub-range. The interval size is dependent on the breadth of the sub-range, a broader sub-range has a larger interval size so that the whole breadth of the sub-range can be scanned quickly.

In response to a lower quality score, the optimizer sets a broader sub-range and a larger interval size, conversely in response to a higher quality score, indicative that only a small change in absolute intensity is needed to reach the threshold, the optimizer sets a narrower sub-range with a smaller interval size.

The sub-range and interval size information determined by the optimizer15is passed to the control unit12, which in response alters the intensity of the LED element3to increase or decrease the absolute intensity value based on received sub-range and interval information from the optimizer15until a threshold pattern score is reached.

The pattern score generator uses a machine learning model adapted to receive the output of the ADC10as an input and that has been trained to identify the sought for physiological signal and to output a confidence level that the input signal comprises all expected features within the physiological signal. Examples of suitable machine learning models for the purpose may use, for example, linear regression, convolutional neural networks and Long short-term memory (LSTM architecture).

The identified physiological signal is processed to determine physiological variable values. The processing steps required will depend on the physiological variable being measured. IoT Health Monitoring Device of Oxygen Saturation (SpO2) and Heart Rate Level; OY Tham; 2020 1st International Conference on Information Technology, Advanced Mechanical and Electrical Engineering (ICITAMEE). https://www.researchgate.net/publication/352264532_IoT_Health_Monitoring_Device of_Oxygen_Saturation_SpO2_and_Heart_Rate_Level describes example processing steps to determine SpO2 and heart rate.

In alternative embodiments, the device may be sized differently and/or take different forms. For example, rather than comprising a metal ring as a mounting structure, the device be comprised from a strip or loop of fabric or elastic material. The device may be sized to fit around another body part, e.g. leg, arm or chest. Alternatively, the device may take, for example, the form of a patch adapted to adhere or otherwise lie against the skin. It is not necessary, in all embodiments, for the device to extend circumferentially around the body part it is mounted against.

The Abstract is provided with the understanding that it is not intended be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description herein has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the examples in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the examples presented or claimed. The disclosed embodiments were chosen and described in order to explain the principles of the embodiments and the practical application, and to enable others of ordinary skill in the art to understand the various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the appended claims below cover any and all such applications, modifications, and variations within the scope of the embodiments.

Although specific embodiments of the subject matter have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing from the scope of the disclosed subject matter. The scope of the disclosure is not to be restricted, therefore, to the specific embodiments, and it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present disclosure.