Adhesion of wearable optical physiological monitoring devices

Abstract

The present invention relates to a non-invasive cardiac monitoring device that records cardiac data to infer physiological characteristics of a human, such as cardiac arrhythmias and other vital signs. Some embodiments of the present invention allow for long-term monitoring of physiological signals. In further embodiments, ECG and PPG data can be processed to calculate pulse arrival times. Some embodiments include a chest-worn cardiac monitoring device that includes both ECG and PPG sensors in close contact with a mammal for long-term detection of cardiovascular signals.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 423,756, filed November 8, 2022, and entitled "ELECTRICAL COMPONENTS FOR PHYSIOLOGICAL MONITORING DEVICE," the disclosure of which is incorporated herein by reference in its entirety for all purposes. All applications for which a foreign or domestic priority claim is identified in the Application Data Sheet filed with this application are hereby incorporated by reference pursuant to 37 CFR 1.57. [Background technology]

[0002] For purposes of this disclosure, certain aspects, advantages, and novel attributes of various embodiments are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, various embodiments may be implemented to achieve one or more advantages taught herein, but may not necessarily achieve other advantages that may be taught or suggested herein. [Technical Field]

[0003] Disclosed herein are materials, devices, methods, and systems for monitoring physiological signals. For example, such physiological signals may include cardiac signals, such as electrocardiogram signals.

[0004] 2. Description of Related Art Abnormal heart rhythms, or arrhythmias, can cause a variety of symptoms, including loss of consciousness, palpitations, dizziness, and even death. Arrhythmias that cause these symptoms are often indicators of serious underlying cardiac disease. Identifying these symptoms as being due to abnormal heart rhythms is important because treatment with various procedures, such as pacemaker implantation or percutaneous catheter ablation, can successfully correct these problems and prevent serious illness or death. For example, monitors such as Holter monitors are currently used to monitor heart rhythm. Summary of the Invention

[0005] The systems, methods, and apparatuses of the present disclosure each have several innovative aspects, no single one of which is solely responsible for all of the desirable attributes disclosed herein. The details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below.

[0006] In some aspects, the technology described herein relates to an electronic device configured to monitor physiological signals of a user, the electronic device including: a housing at least partially enclosing a circuit board configured to process the physiological signals to infer a physiological characteristic of the user; flexible wings extending from the housing and configured to be affixed to a surface of the user; and an optical sensor assembly disposed on the flexible wings and configured to obtain a photoplethysmography signal, the optical sensor assembly including an optical emitter configured to emit light and an optical detector configured to receive the light, wherein at least a portion of the light emitted by the optical emitter is directed towards the skin (e.g., chest) of the user and is received from the skin (e.g., chest) of the user by the optical detector, and the optical sensor assembly includes a first directional layer between the optical emitter and the surface of the user. a first directional layer between the light detector and the surface of the user, the first directional layer directing light from the light emitter toward the surface of the user, and the second directional layer directing light from the surface of the user toward the light detector.

[0007] In some embodiments, the technology described herein relates to an electronic device, wherein the first directional layer comprises a first convex lens and the second directional layer comprises a second convex lens.

[0008] In some aspects, the technology described herein relates to an electronic device in which a first convex lens and a second convex lens are positioned to extend below a flexible wing such that when the electronic device is attached to a user's skin (e.g., chest), the first convex lens and the second convex lens are pressed against the user's skin (e.g., chest).

[0009] In some embodiments, the technology described herein relates to an electronic device, wherein the optical sensor assembly further includes an opaque barrier disposed between the first directional layer and the second directional layer.

[0010] In some embodiments, the technology described herein relates to an electronic device, wherein an opaque barrier prevents at least a portion of light emitted by a light emitter from being received by a light detector without passing through the skin (e.g., chest) of a user.

[0011] In some aspects, the technology described herein relates to an electronic device, wherein an opaque barrier is configured to direct at least a portion of light from a surface of a user to a light detector.

[0012] In some embodiments, the technology described herein relates to an electronic device further comprising a reflective layer disposed between the opaque barrier and the user's skin (eg, chest).

[0013] In some embodiments, the technology described herein relates to an electronic device, wherein the reflective layer reflects light from the first directional layer.

[0014] In some embodiments, the technology described herein relates to an electronic device, wherein a first directional layer and a second directional layer protrude beyond a portion of an opaque barrier and overlap at least a portion of the opaque barrier to increase the contact area with a user's skin (e.g., chest).

[0015] In some embodiments, the technology described herein relates to an electronic device, wherein the first and second directional layers are configured to guide or redirect the passage of light of specific wavelengths.

[0016] In some embodiments, the technology described herein relates to an electronic device, wherein the first directional layer comprises a first concave lens and the second directional layer comprises a second concave lens.

[0017] In some embodiments, the technology described herein relates to an electronic device, wherein a first concave lens and a second concave lens are formed from a high-index material that is index-matched to the stratum corneum of a user's chest.

[0018] In some embodiments, the technology described herein relates to an electronic device, wherein the first directional layer includes a first half-ball lens and the second directional layer includes a second half-ball lens.

[0019] In some embodiments, the technology described herein relates to an electronic device, wherein the first half-ball lens and the second half-ball lens each comprise a sapphire half-ball lens.

[0020] In some embodiments, the technology described herein relates to an electronic device, further including a first adhesive layer configured to affix the first half ball lens to the light emitter and a second adhesive layer configured to affix the second half ball lens to the light detector.

[0021] In some aspects, the technology described herein relates to an electronic device, wherein the circuit board comprises a flex circuit board.

[0022] In some embodiments, the technology described herein relates to an electronic device further including a backing substrate that exerts pressure on the circuit board to increase contact between the light emitter and the user's skin (e.g., chest), to increase contact between the light detector and the user's skin (e.g., chest), or to increase contact between the light emitter and the user's skin (e.g., chest) and between the light detector and the user's skin (e.g., chest).

[0023] In some aspects, the technology described herein relates to an electronic device, wherein the optical sensor assembly includes a plurality of light emitters, including a light emitter, and when the flexible wings are affixed to a surface of a user, the plurality of light emitters pinch the user's skin (e.g., chest skin) such that a portion of the skin (e.g., chest skin) is positioned between the plurality of light emitters, and the plurality of light emitters focus light toward the portion of the skin (e.g., chest skin) positioned between the plurality of light emitters.

[0024] In some aspects, the technology described herein relates to an electronic device, wherein the optical sensor assembly includes a plurality of photodetectors, including a photodetector, and when the flexible wings are attached to a surface of a user, the plurality of photodetectors sandwich the user's skin (e.g., chest skin) such that a portion of the skin (e.g., chest skin) is positioned between the plurality of photodetectors, and the plurality of photodetectors receive light from the portion of the skin (e.g., chest skin) positioned between the plurality of photodetectors.

[0025] In some aspects, the technology described herein relates to an electronic device in which, when the flexible wings are attached to a surface of a user, the light emitter and the light detector sandwich the user's skin (e.g., chest skin), with a portion of the skin (e.g., chest skin) positioned between the light emitter and the light detector, and light from the light emitter is guided through the user's skin (e.g., chest skin) to the light detector.

[0026] In some aspects, the technology described herein relates to an electronic device, wherein the light sensor assembly further includes a fiber optic cable or light guide configured to direct light from the light emitter toward the skin (e.g., chest) of a user.

[0027] In some embodiments, the technology described herein relates to an electronic device, further including a spring configured to exert pressure to increase contact between the light emitter and the skin (e.g., chest) of a user and to increase contact between the light detector and the skin (e.g., chest) of the user.

[0028] In some aspects, the technology described herein relates to an electronic device configured to monitor physiological signals of a user, the electronic device including: a housing at least partially enclosing a circuit board configured to process the physiological signals to infer a physiological characteristic of the user; flexible wings extending from the housing and configured to conform to a surface of the user corresponding to the user's chest; an optical sensor assembly disposed on the flexible wings and configured to obtain a photoplethysmogram signal; and an adhesive layer coupled to the surface of the flexible wings and configured to adhere the electronic device to the surface of the user, wherein the adhesive layer includes an optically transparent adhesive layer.

[0029] In some aspects, the technology described herein relates to an electronic device further including a brightness enhancing film configured to reflect or refract light generated by the light sensor assembly toward the skin (e.g., chest) of a user.

[0030] In some aspects, the technology described herein relates to an electronic device, wherein a brightness enhancing film is disposed between an adhesive layer and a photosensor assembly.

[0031] In some aspects, the technology described herein relates to electronic devices in which a brightness enhancing film is integrated with an adhesive layer.

[0032] In some aspects, the technology described herein relates to an electronic device, wherein the brightness enhancement film is substantially coplanar with the optical elements of the photosensor assembly.

[0033] In some embodiments, the technology described herein relates to an electronic device, where a brightness enhancement film rises toward a circuit board and provides a space for tenting a user's skin (e.g., chest skin).

[0034] In some aspects, the technology described herein relates to an electronic device, wherein the optical sensor assembly includes a photodiode and a light emitting diode.

[0035] In some embodiments, the technology described herein relates to an electronic device in which an optically clear adhesive layer bonds a photodiode and a light emitting diode to the skin (e.g., chest) of a user.

[0036] In some aspects, the technology described herein relates to an electronic device, wherein an optically transparent adhesive layer surrounds a photodiode and a light emitting diode without covering the photodiode and the light emitting diode.

[0037] In some embodiments, the technology described herein relates to an electronic device further comprising a wicking material configured to absorb or evaporate sweat or bodily secretions.

[0038] In some aspects, the technology described herein relates to an electronic device, wherein the moisture-absorbing material comprises a polyester-based material.

[0039] In some aspects, the technology described herein relates to electronic devices in which a moisture-absorbing material is interwoven with an adhesive layer.

[0040] In some aspects, the technology described herein relates to an electronic device in which a moisture-absorbing material is disposed around an optical element of an optical sensor assembly.

[0041] In some aspects, the technology described herein relates to an electronic device further including a channel disposed around the optical element of the optical sensor assembly and configured to allow sweat or bodily secretions to evaporate or escape.

[0042] In some aspects, the technology described herein relates to an electronic device, wherein the channel is in an adhesive layer.

[0043] In some aspects, the technology described herein relates to an electronic device, wherein the circuit board comprises a flexible printed circuit board.

[0044] In some aspects, the technology described herein relates to an electronic device, wherein a flexible printed circuit board includes a backing layer having channels that allow sweat or body secretions to evaporate or escape.

[0045] In some aspects, the technology described herein relates to an electronic device in which an adhesive layer and an optical element of a light sensor assembly are attached to a backing layer.

[0046] In some embodiments, the technology described herein relates to electronic devices that further include a physical barrier between the adhesive layer and the optical element that prevents leaking adhesive from contacting the optical element.

[0047] In some aspects, the technology described herein relates to an electronic device, wherein the physical barrier is sloped toward the adhesive layer.

[0048] In some aspects, the technology described herein relates to an electronic device, wherein the adhesive layer comprises a plurality of adhesives.

[0049] In some embodiments, the technology described herein relates to an electronic device, wherein the plurality of adhesives includes a first adhesive and a second adhesive, the first adhesive being closer to an optical element of the optical sensor assembly than the second adhesive, and the viscosity of the first adhesive being different from the viscosity of the second adhesive.

[0050] In some embodiments, the technology described herein relates to an electronic device, wherein the first adhesive is thinner than the second adhesive.

[0051] In some aspects, the technology described herein relates to an electronic device, further comprising an adhesive layer at least partially surrounding the optical sensor assembly.

[0052] In some aspects, the technology described herein relates to an electronic device, wherein an adhesive layer at least partially surrounding an optical sensor assembly is not optically transparent.

[0053] In some aspects, the technology described herein relates to an electronic device further including a hydrophobic or hydrophilic material at least partially surrounding the optical sensor assembly to direct sweat or bodily secretions away from the optical sensor assembly.

[0054] In some aspects, the technology described herein relates to an electronic device further including perforations disposed around the optical element of the optical sensor assembly and configured to allow sweat or bodily secretions to evaporate or escape.

[0055] The embodiments described herein are directed to physiological monitoring devices that can be continuously and comfortably worn by a human or animal subject for at least one week or longer, and more typically for two to three weeks or longer. In some embodiments, the device is specifically designed to sense and record cardiac (e.g., electrocardiogram, ECG) data, although various alternative embodiments may sense and record one or more additional physiological parameters. Such physiological monitoring devices may include many features to facilitate and / or enhance the patient experience and to provide more accurate and timely diagnosis of cardiac arrhythmias.

[0056] Some embodiments include an electronic device for monitoring a user's physiological signals, the electronic device including: a housing containing a circuit board; wings extending from the housing and configured to conform to a surface of the user, the flexible wings having a bottom surface and a top surface; electrodes coupled to the wings, the electrodes being in electrical communication with the circuit board and configured to be positioned in conformal contact with the surface of the user to detect the physiological signals; a light sensor; and an adhesive layer coupled to the bottom surfaces of the wings to adhere the electronic device to the user. The adhesive layer has a bottom surface and a top surface interfacing with the bottom surfaces of the wings to adhere the electronic device to the user, and has a thickness between the bottom and top surfaces. The light sensor includes a light emitting diode (LED) and at least one photodiode. The wings have a thickness between the bottom and top surfaces. The light sensor includes at least one emitter and at least one detector. The light sensor is coupled to a wing. The light sensor is coupled to another wing. The light sensor includes another LED configured to emit light of a different wavelength than the LED. The LED or another LED is configured to emit green light. The LED or another LED is configured to emit infrared light. The optical sensor includes at least two photodiodes. The first photodiode illuminates the user's body with infrared light, and the second photodiode illuminates the user's body with red light. The distance between the LED and the at least one photodiode depends on the wavelength of the light emitted from the LED. The distance between the LED and the at least one photodiode depends on the desired penetration depth of the light into the user's skin or body. The circuit board is configured to process electrocardiogram (ECG) data from the electrodes and photoplethysmography (PPG) data from the optical sensor to calculate or infer a physiological characteristic of the user. The circuit board is configured to calculate a pulse arrival time (PAT) metric based on the ECG and PPG data. The PAT metric is calculated for each heartbeat. The PAT metric is inversely proportional to the user's blood pressure. The user's blood pressure is calculated based on the relationship between peaks and / or troughs in the PPG data and the ECG data.The electronic device is configured to compare the calculated blood pressure with a baseline blood pressure, which the electronic device receives from a third-party blood pressure measurement device. The circuit board is configured to detect peaks and / or valleys in the ECG and PPG data. The circuit board is configured to determine differences in the peaks and / or valleys in the ECG and PPG data to calculate a PAT metric. The circuit board is configured to calculate a regression trend of the ECG and PPG data. The regression trend is a linear regression trend. The regression trend correlates the ECG data and / or PPG data and / or impedance data with hemodynamics or other characteristics of the user's blood flow or stroke volume. The electronic device of any of the preceding claims herein or other claims, wherein the regression trend further tracks changes in the behavior of the ECG or PPG or impedance data values, blood pressure values, and / or correlation over time. The electronic device of any of the preceding claims herein or other claims, wherein the electronic device applies the regression trend to subsequently estimate blood pressure directly from the ECG and / or PPG and / or impedance sensor data. The circuit board is configured to calculate a difference in wavelength between the light transmitted from the LED and the light received from the photodiode. The circuit board is configured to determine the user's heart quality based on the calculated difference. The electrodes and optical sensor are positioned on at least one of the user's chest, the user's limb, the user's torso, the user's arm, the user's upper arm, the user's torso, the user's chest, the user's shoulder, the user's upper arm, the user's wrist, the user's finger, the user's earlobe, the user's forehead, the user's leg, the user's foot, the user's toe, or the user's blood vessel. The electrodes and optical sensor collect data from the user's blood vessel. The electrodes and optical sensor collect data from the same blood vessel. The electrodes and optical sensor collect data from different blood vessels. The electronic device further includes an impedance sensor configured to reduce noise from the collected signal based on the detected movement. The electronic device further includes an impedance sensor configured to measure hemodynamic information.The electronic device further includes an impedance sensor configured to measure impedance electrocardiography. The measured impedance electrocardiography can be applied to improve the accuracy of PAT metrics when estimating blood pressure. The electronic device further includes an impedance sensor configured to measure impedance between the first electrode and the second electrode. The electronic device further includes an impedance sensor configured to measure impedance between the third electrode and the fourth electrode. The first electrode and the second electrode are closer to the center of the chest than the third electrode and the fourth electrode. The electrodes are located on the chest and aligned with the spine. The electrodes include a first electrode, a second electrode, a third electrode, and a fourth electrode. The impedance sensor senses between two or four electrodes. The device applies a current to the first electrode and the second electrode and records the resulting voltage at the third electrode and the fourth electrode. The first and second electrodes are outer electrodes, and the third and fourth electrodes are inner electrodes. The current is low. The device includes a fifth and sixth electrode, and the third, fourth, fifth, and sixth electrodes measure impedance across the user's chest. The first, second, third, and fourth electrodes are aligned with the spine. The fifth and sixth electrodes are not aligned with the spine. The first, second, third, and fourth electrodes are configured to measure impedance. The fifth and sixth electrodes are configured to measure ECG signals. The device or external computing system is configured to determine atrial fibrillation burden from the detected signals from the electrodes and / or optical sensor. The atrial fibrillation burden includes the amount of time the user spent in atrial fibrillation during a period of time. The atrial fibrillation burden includes the amount of time the user spent in atrial fibrillation during sleep periods and wakefulness periods. The device or external computing system is further configured to provide a report, the report including the likelihood of cardiac arrhythmia. The report includes a graph of the atrial fibrillation burden over time. The report includes an indication of atrial fibrillation. The report includes a monitoring period of at least 3 days, 14 days, or 21 days. The electronic device is configured to transmit detection signals or derivative signals of the electrodes and optical sensor to an external computing device, which is configured to determine the physiological signal of the user. The external computing system is a server or a gateway.The external computing system is a smartphone. The external computing system communicates with the transmitter via a smartphone intermediary device. The electronic device further includes an accelerometer configured to measure user movement. The electronic device is configured to discard the recorded physiological data if data from the accelerometer indicates high user movement. The electronic device is configured to remove noise from the recorded physiological data based on the frequency of the movement data. The device or the external computing system is further configured to determine an atrial fibrillation burden, the atrial fibrillation burden including an amount of time spent in atrial fibrillation during the user's movement. The user's movement includes a first degree of movement and a second degree of movement. The electrodes and optical sensor are housed in a chest strap. The electrodes and optical sensor are housed in a chest patch. The electrodes and optical sensor are built into a watch configured to be worn on a human wrist. The electrodes and optical sensor are built into a wearable fitness band. The electronic device is configured to detect or infer arrhythmia based on signals from the electrodes and optical sensor. The arrhythmia includes an onset of arrhythmia. The arrhythmia includes past occurrences of arrhythmia. The arrhythmia includes at least one of ventricular tachycardia, supraventricular tachycardia, ectopy, ventricular fibrillation, or extended pause. The housing is configured to be detachable from the electronic device and alterable while separate from the electronic device. The electronic device is further configured to track an amount of light reflected back to the detector of the PPG sensor. The amount of light reflected back to the detector of the PPG sensor is modulated by pulsations of blood flow through the user's blood vessels. The amount of reflected back light corresponds to hemodynamic information. The electronic device is configured to measure ECG p-waves, ECG R-peaks, measure PPG valleys and / or troughs, measure inflection points along the systolic rise, and / or determine a weighted center of gravity for each pulse. The electronic device is configured to measure ECG p-waves and infer arrhythmia based on the measured ECG p-waves. The electronic device is configured to measure ECG p-waves and determine PAT based on the measured ECG p-waves.The electronic device is configured to measure a delay between a signal from the electrodes and a signal from the optical sensor. The user's blood pressure is derived based on the measured delay between the signal from the electrodes and the signal from the optical sensor. The electronic device is configured to measure an electrical potential via the electrodes in an electrical pathway of the heart, including the sinoatrial node and / or the atrioventricular node. The electronic device further includes a capacitor configured to filter noise due to other electrical circuits. The electronic device is configured to measure total electrical conductance by passing a current between the electrodes and measuring a voltage between the other electrodes. The electrodes are driven with the same input signal. The electrodes include a first electrode, a second electrode, a third electrode, and a fourth electrode. Impedance can be sensed between two of the four electrodes. The sensed impedance can be collected on a perpendicular vector substantially parallel to the aorta. The sensed impedance can be collected at an angle on the heart. The first electrode and the second electrode are positioned above and below the heart, respectively. The third electrode and the fourth electrode are positioned on the left and right sides of the heart, respectively. The first and second electrodes are positioned on the left and right sides of the heart, respectively.

[0057] Some examples include an electronic device for monitoring a physiological signal of a user, the electronic device including: a housing enclosing a circuit board; electrodes coupled to the housing, the electrodes in electrical communication with the circuit board and configured to be placed in conformal contact with a surface of the user to detect the physiological signal; a light emitting diode (LED) and a detector coupled to the circuit board, the LED configured to emit light and the detector configured to detect the light; and the electronic device also including an adhesive layer for adhering the electronic device to the user.

[0058] Some embodiments include an electronic device for monitoring a physiological signal of a user, the electronic device including: a housing enclosing a circuit board; electrodes coupled to the housing, the electrodes in electrical communication with the circuit board and configured to be positioned in conformal contact with a surface of a user to detect the physiological signal; and an emitter and a detector coupled to the circuit board, the emitter configured to emit light and the detector configured to detect light, the electronic device also including an adhesive layer for adhering the electronic device to the user. The electronic device includes a conformal coating over the LED and the detector. The conformal coating is further applied between the LED and the detector. The conformal coating between the LED and the detector is flush with the coating of the LED or the detector. The conformal coating between the LED and the detector is recessed from the coating of the LED or the detector. The conformal coating is 10 to 1000 micrometers thin. The conformal coating is 50 to 500 micrometers thin. The layer of conformal coating over the LED is substantially the same thickness as the layer of conformal coating over the detector. The electronic device further includes a barrier between the LED and the detector, the barrier configured to reduce or eliminate crosstalk between the LED and the detector, and the conformal coating is also applied on the barrier. The barrier is an opaque barrier. The opaque barrier prevents or mitigates environmental light outside the electronic device from affecting the LED or photodiode. The opaque barrier is at least one of: positioned adjacent to the LED or photodiode; dome-shaped; positioned above the LED or photodiode; donut-shaped and surrounding the LED or photodiode; or washer-shaped and surrounding the LED or photodiode. The electronic device further includes a reflective layer positioned adjacent to the barrier. The reflective barrier is configured to contact the patient's skin and prevent another barrier from contacting the patient's skin. The reflective barrier is configured to reflect light exiting the user's body back into the user's body.The reflective barrier is configured to reflect light exiting the user's body away from the detector active area back toward the detector active area. The LED is configured to indent the user's skin. The detector is configured to indent the user's skin. The electronic device further includes an additional adhesive layer configured to firmly hold the LED and detector on the user's skin. The adhesive layer forms an outer adhesive layer, and the additional adhesive layer forms an inner adhesive layer. The outer adhesive layer has a greater thickness than the inner adhesive layer. The outer adhesive layer has greater adhesion properties than the inner adhesive layer. The outer adhesive layer includes a load-bearing adhesive, and the inner adhesive layer includes an optically clear adhesive. The inner adhesive layer includes a harder material than the outer adhesive layer. The distance between the center of the LED and the edge of the detector proximate the LED is at least one of 2-3, 6-8, or 10-30 micrometers. The housing includes a first mating component, the adhesive layer includes a second mating component, and the housing is configured to be detachable from the adhesive layer via the first and second mating components. The detector detects light emitted from the LED through the user's skin. The detector detects light emitted from the LED reflected from the user's body. The electronic device further includes a first glass lens configured to direct light from the LED to the user's skin. The electronic device further includes a second glass lens configured to direct light from the user's skin to the detector. The electronic device further includes a barrier between the first and second glass lenses configured to block at least a portion of light passing directly from the LED to the detector. The first or second glass lens includes at least one of a dome shape, a spherical shape, a meniscus shape, or a 180-degree curved dome shape. The first or second glass lens includes a dome shape configured to contact the skin surface and another portion that contacts the barrier. The first or second glass lens includes a dome shape configured with the entire curved portion contacting the user's skin. The detector is configured to detect at least a portion of the light emitted from the LED that passes directly from the first glass lens through the user's skin to the second glass lens.The electronic device according to any of the preceding claims or any other claims herein, wherein the detector is configured to detect at least a portion of emitted light from the LED that is transmitted from the first glass lens, modulated by the user's pulsatile blood, and exits the user's body to the second glass lens. The electronic device according to any of the preceding claims or any other claims herein, wherein the electronic device is further configured to combine the transmitted light and the reflected light and combine the signals to make an inference. The electronic device according to any of the preceding claims or any other claims herein, wherein the first glass lens or the second glass lens is configured to indent the user's skin. The first glass lens and the second glass lens are configured to indent the user's skin. The amount of indentation is based on the amount of emitted light transmitted from the first glass lens to the second glass lens. The amount of indentation is based on whether the indentation prevents signal capture of the surface blood vessels, thereby blocking the surface blood vessels. The electronic device further includes a glass lens configured to direct light from the user's skin to the detector. The electronic device is configured to project light onto the user's chest. The electronic device is configured to detect light from the user's chest. Both the LED and the detector are positioned on the user's chest, not on the back. The LED or the detector is configured to indent the user's skin. The electronic device further includes an optically transparent film or adhesive having wavelength-guiding properties configured to redirect light onto the patient's skin at one or more angles proximal to the detector. The detector is configured to indent the user's skin to form a tent in the skin, and the detector is configured to detect light from the LED that passes through the tent in the skin. The detector is positioned on a first rail and the LED is positioned on a second rail, and the detector and the LED are elevated from a substrate via the first and second rails, respectively. The detector is configured to indent one side of the user's skin, and the second detector is configured to indent another side of the user's skin to form a tent in the skin, and the detector and the second detector are configured to detect light from the LED that passes through the tent in the skin.The LED is configured to indent the user's skin, forming a tent-shaped region of the skin, and the detector is configured to detect light irradiated by the LED into the tent-shaped region of the skin. The LED is configured to indent one side of the user's skin and a second LED is configured to indent the other side of the user's skin, forming a tent-shaped region of the skin, and the detector is configured to detect light irradiated by the LED and the second LED into the tent-shaped region of the skin. The LED is configured to directionally irradiate light into the tent-shaped region of the skin. The wearable device further includes light piping configured to channel light from the LED and irradiate light into the tent-shaped region of the skin. The light piping is configured to channel light toward the tent-shaped region of the skin but not in a direction away from the tent-shaped region of the skin. The light piping is configured to provide index matching between at least two of the LED, air, the user's skin, or a lens. The LED is donut-shaped. The LED is an incomplete donut-shaped. The electronic device includes one or more microfluidic channels configured to allow sweat or goop to escape. The one or more microfluidic channels are adjacent to the LED or detector. The electronic device of any preceding claim or any other claim herein, wherein an electronic device further includes one or more microfluidic channels configured to allow sweat or goop to evaporate. The electronic device further includes a contact portion that presses a portion of the LED or detector toward the patient's skin. The electronic device further includes a hygroscopic material on the contact portion that is configured to press against the LED or detector. The electronic device further includes a physical barrier that prevents extrusion of an adhesive layer onto the LED or detector during use of the electronic device over time. At least a portion of the physical barrier is angled toward the adhesive layer. The LED is configured to irradiate light of a first wavelength toward the tented region, and the electronic device further includes a second LED configured to emit light of a second wavelength toward the tented region. The detector is configured to detect light from the LED and the second LED, and the electronics is configured to filter the light from the LED and the light from the second LED.The electronic device further includes filtering the light received by the photodiode. The electronic device is configured to filter light of a certain wavelength or a certain range of wavelengths from the light received by the photodiode. The electronic device is configured to filter the light via a physical filter disposed near or adjacent to the photodiode. The electronic device is configured to filter the light via signal processing. The detector is configured to simultaneously detect light from the LED and the second LED. When the LED emits light of the first wavelength, the second LED is turned off. The second LED is configured to indent the user's skin on a second side of the tented region of the skin, and the detector is configured to detect light emitted from the LED and the second LED into the tented region of the skin. The second LED further forms a second tented region of the skin, and the second detector is configured to detect light emitted by the second LED into the second tented region. The third LED is further configured to indent the user's skin to help form a second tent-shaped region of the skin, and the second detector is configured to detect light emitted by the second LED and the third LED into the second tent-shaped region. The LEDs and the detector are arranged in a circular array. The tent-shaped region of the skin is within an inner region of the circular array. The LEDs are arranged in a linear array. The detectors are arranged in a linear array. The electronic device further includes a lens that directs light from the LEDs toward the tent-shaped region of the skin. The lens has a first surface not adjacent to the tent-shaped region of the skin and a second surface adjacent to the tent-shaped region of the skin, the first surface being more transparent than the second surface such that more light passes through the first surface than the second surface. The electronic device further includes a second adhesive layer, the adhesive layer and the second adhesive layer having different adhesive properties. The adhesive layer includes one or more openings or slits. The electronic device further includes one or more wicking materials configured to evaporate sweat or goop. The one or more wicking materials are woven into the adhesive. The one or more wicking materials are disposed proximate to the adhesive.The electronic device further includes a flexible layer overlying the LED and the detector, the flexible layer configured to apply pressure to the LED and the detector toward the patient's skin when the electronic device is worn by a user. The electronic device further includes an opaque barrier disposed between the LED and the detector. The opaque barrier is disposed closer to the LED than the detector. The electronic device further includes a first set of optical fibers connected to the LED, the first set of optical fibers irradiating light from the LED to the user's skin. The electronic device further includes a photodiode. The electronic device further includes a second set of optical fibers connected to the LED, the second set of optical fibers detecting an optical signal from the user's skin and passing the signal to the photodiode. The electronic device further includes a brightness enhancement film disposed between the LED and the detector. The electronic device further includes an optically clear adhesive layer configured to affix the LED to the user's skin. The electronic device further includes an optically clear adhesive layer configured to affix the detector to the user's skin. The electrodes are disposed on a portion of the body different from the LED or the photodiode. The electrodes are held to the body's skin via a portion of the adhesive different from the LED or the photodiode. The electrodes are held to the body's skin via a portion of the adhesive different from the LED or the photodiode. The electronic device further includes a flexible substrate, the photodiode and the LED are disposed on the flexible substrate. The flexible substrate is curved to have protrusions or depressions such that depressions or indentations are formed on the skin when the electronic device is applied to the patient's skin. The flexible substrate is flexible to conform to the curvature of the skin. The electronic device further includes a rigid substrate, the photodiode and the LED are disposed on the rigid substrate. The electronic device further includes converting light received by the photodiode into an electrical signal and transmitting the electrical signal to the housing. The electronic device further includes circuitry within the housing configured to transmit light received by the photodiode to the housing and convert the light into an electrical signal. The electronic device further includes a film configured to transmit light in one direction but not in another. The film is configured to transmit light from the LED but not the LED. The film is configured to transmit light from the photodiode but not the photodiode. The electronic device further includes a hydrophilic material below or around the LED or photodiode, the hydrophilic material configured to draw fluid away from the LED or photodiode. The electronic device further includes a hydrophobic material between the LED and the photodiode, the hydrophobic material configured to repel fluid from both the LED and the photodiode. The electronic device further includes a hydrophobic material over the LED or photodiode.The electrodes are on a first wing, and the LED and photodiode are on a second wing. The electrodes are on the same wing as the LED and photodiode. The electronic device is configured to be depressed by a user while the LED emits light and the photodiode collects a PPG signal. The electronic device is configured to be depressed by a user while the electrodes collect an ECG signal. The electronic device is configured to determine blood pressure after the user presses down on the electronic device for a certain period of time. At least a portion of the traces for the electrodes extend parallel to at least a portion of the traces for the optical sensor. The electronic device further includes a second electrode and a second adhesive, the first adhesive being configured to hold the electrode on the user's skin, and the second adhesive being configured to hold the second electrode and the one or more optical sensors on the user's skin. The first adhesive and the second adhesive are physically separated. The optical component is configured to be removable from the electronic device. The electronic device is configured to input a signal signature to the LED and apply a match filter to the optical signal received by the photodiode.

[0059] While particular embodiments and examples are disclosed herein, the inventive subject matter extends beyond the specifically disclosed example embodiments to other alternative embodiments and / or uses, and to modifications and equivalents thereof. [Brief explanation of the drawings]

[0060] [Figure 1A] FIG. 1A is a perspective view of one embodiment of a physiological monitoring device. [Figure 1B] FIG. 1B is an exploded view of one embodiment of a physiological monitoring device. [Figure 2A] FIG. 2A is a top perspective view of one embodiment of a physiological monitoring device. [Figure 2B] FIG. 2B is a bottom view of one embodiment of a physiological monitoring device. [Figure 2C] FIG. 2C is a top perspective view of one embodiment of a physiological monitoring device, including a liner. [Figure 2D]FIG. 2D is a bottom view of one embodiment of a physiological monitoring device, including a liner. [Figure 3A] FIG. 3A is a perspective view of one embodiment of a physiological monitoring device. [Figure 3B] FIG. 3B is a top view of one embodiment of a physiological monitoring device. [Figure 3C] FIG. 3C is a bottom view of one embodiment of a physiological monitoring device. [Figure 3D1] FIG. 3D1 is a side view of one embodiment of a physiological monitoring device. [Figure 3D2] FIG. 3D2 shows a side view of ridges configured to seal the top and bottom of the housing of one embodiment of a physiological monitoring device. [Figure 3E] FIG. 3E is a bottom view of the physiological monitoring device, with the layers shown transparent to allow for better understanding of the device's construction. [Figure 3F] FIG. 3F is a top view of the physiological monitoring device, with the layers shown transparent to allow for better understanding of the device's construction. [Figure 3G] FIG. 3G is an exploded view of the components of the physiological monitoring device. [Figure 3H] FIG. 3H is an exploded view of the components of the physiological monitoring device. [Figure 4] FIG. 4 is a schematic diagram of a sensor platform according to one embodiment. [Figure 5A] FIG. 5A is a schematic diagram according to at least one embodiment. [Figure 5B] FIG. 5B is a schematic diagram according to at least one embodiment. [Figure 5C] FIG. 5C is a schematic diagram according to at least one embodiment. [Figure 6] FIG. 6 is a schematic diagram of an apparatus according to one embodiment. [Figure 7] FIG. 7 is a schematic diagram of an apparatus according to one embodiment. [Figure 8] FIG. 8 is a schematic diagram of an optical sensor according to one embodiment. [Figure 9]FIG. 9 is a schematic diagram of a user's blood pressure according to one embodiment. [Figure 10A] FIG. 10A is a graph showing ECG data and PPG data of a user according to one embodiment. [Figure 10B] FIG. 10B is a graph showing ECG and PPG data of a user according to one embodiment. [Figure 11] FIG. 11 is a graph illustrating a user's pulse arrival time (PAT) versus measurement time, according to one embodiment. [Figure 12A] FIG. 12A is an example of electrodes measuring conductivity across the thorax, according to one embodiment. [Figure 12B] FIG. 12B is an example of electrodes and an ECG sensor measuring electrical conductivity across the thorax, according to one embodiment. [Figure 13A] FIG. 13A is a graph of an impedance electrocardiogram, according to one embodiment. [Figure 13B] FIG. 13B is a graph of pulse arrival time determination according to one embodiment. [Figure 14A] FIG. 14A is a side view of an embodiment of an optically clear adhesive under a photodiode and an LED according to some embodiments. [Figure 14B] FIG. 14B is a top view of an optically clear adhesive under a photodiode and an LED according to some embodiments. [Figure 15A] FIG. 15A illustrates an embodiment for indenting the skin of a patient according to some embodiments. [Figure 15B] FIG. 15B illustrates an example of using two extensions of a wearable device to indent the patient's skin according to some embodiments. [Figure 15C] FIG. 15C illustrates an embodiment of applying a fiber optic cable to emit light into a depression in a user's skin according to some embodiments. [Figure 16] FIG. 16 is a top view of an embodiment for removing sweat or other goop from electronic components according to some embodiments. [Figure 17]FIG. 17 illustrates an embodiment with contact portions that apply pressure to the LED and / or photodiode for better bonding with the skin, according to some embodiments. [Figure 18A] FIG. 18A illustrates an embodiment of a physical barrier to prevent adhesive from flooding electronic devices, according to some embodiments. [Figure 18B] FIG. 18B illustrates an embodiment of a single LED in the shape of a donut or ring, according to some embodiments. [Figure 19] FIG. 19 illustrates an embodiment with LEDs that emit light of different wavelengths, according to some embodiments. [Figure 20] FIG. 20 illustrates an embodiment of an LED and photodiode repeater according to some embodiments. [Figure 21] FIG. 21 illustrates examples of different adhesives for wearable devices according to some embodiments. [Figure 22A] FIG. 22A illustrates an embodiment with a single LED and a single photodiode according to some embodiments. [Figure 22B] FIG. 22B illustrates an embodiment having an array of LEDs and an array of photodiodes according to some embodiments. [Figure 22C] FIG. 22C illustrates an embodiment of LEDs and photodiodes distributed in a circular array according to some embodiments. [Figure 23A] FIG. 23A illustrates an example of a protrusion lined with illumination channels according to some embodiments. [Figure 23B] FIG. 23B illustrates an embodiment using rings or light pipes according to some embodiments. [Figure 24] FIG. 24 illustrates an example of a leaf spring compressing certain components of a wearable device, according to some embodiments. [Figure 25] FIG. 25 illustrates an embodiment of a bowl-shaped flexible circuit that is recessed into the skin, according to some embodiments. [Figure 26A] FIG. 26A illustrates an embodiment of an opaque barrier between an LED and a photodiode, according to some embodiments. [Figure 26B] FIG. 26B illustrates an embodiment of direct simulated transmission from an LED through a tented region of skin to a photodiode, according to some embodiments. [Figure 27A] FIG. 27A illustrates a cross-sectional view of an embodiment using a fiber optic bundle for an LED and a photodiode, according to some embodiments. [Figure 27B] FIG. 27B illustrates a side view of an embodiment using a fiber optic bundle, according to some embodiments. [Figure 28A] FIG. 28A shows an example of skin bonding via two doming compounds according to some embodiments. [Figure 28B] FIG. 28B illustrates another example of skin bonding via two doming compounds according to some embodiments. [Figure 28C] FIG. 28C illustrates example circuits 2840, 2860 according to some embodiments. [Figure 28D] FIG. 28D illustrates an example of skin bonding using an inward meniscus shape of a glass lens, according to some embodiments. [Figure 29A] FIG. 29A illustrates the use of high index materials according to some embodiments. [Figure 29B] 29B shows a doming compound protruding beyond an opaque barrier, according to some embodiments. [Figure 29C] FIG. 29C illustrates an example ball lens according to some embodiments. [Figure 30A] FIG. 30A illustrates the use of a waveguide on a surface in some embodiments. [Figure 30B] FIG. 30B illustrates an example of a waveguide flexible circuit 3620 according to some embodiments. [Figure 30C] FIG. 30C illustrates an example of an adhesive used for a dome-shaped glass lens, according to some embodiments. [Figure 30D] FIG. 30D illustrates an example of an adhesive used for an inverted dome shaped glass lens, according to some embodiments. [Figure 31A]FIG. 31A shows an example of a ray trace of LED emitted light according to some embodiments. [Figure 31B] FIG. 31B illustrates an example ray trace of detected light according to some embodiments. [Figure 31C] FIG. 31C illustrates an example of applying a circular pedestal on a flexible substrate below the LED and detector, according to some embodiments. [Figure 31D] FIG. 31D illustrates an example of applying a circular pedestal on a flexible substrate below the LED and detector, according to some embodiments. [Figure 31E] FIG. 31E illustrates an example of applying a circular pedestal on a flexible substrate below the LED and detector, according to some embodiments. [Figure 31F] FIG. 31F illustrates an example of applying a circular pedestal on a flexible substrate below the LED and detector, according to some embodiments. [Figure 31G] FIG. 31G illustrates an example of applying a circular pedestal on a flexible substrate below the LED and detector, according to some embodiments. [Figure 32] FIG. 32 illustrates a mold for a sapphire half-ball glass lens, according to some embodiments. [Figure 33A] FIG. 33A illustrates a clamp capable of clamping an O-ring, according to some embodiments. [Figure 33B] FIG. 33B illustrates a top view of FIG. 33A, according to some embodiments. [Figure 33C] FIG. 33C illustrates a side view and a cross-sectional view of an O-ring, according to some embodiments. [Figure 34A] FIG. 34A shows a prototype of a skin-bonding example according to some embodiments. [Figure 34B] FIG. 34B shows examples of different amounts of light barrier applied, according to some embodiments. [Figure 34C] FIG. 34C shows examples of different amounts of light barrier applied, according to some embodiments. [Figure 34D] FIG. 34D illustrates an example of the operation of a skin coupler according to some embodiments. [Figure 34E] FIG. 34E illustrates an example of the operation of a skin coupler according to some embodiments. [Figure 34F] FIG. 34F shows another example of a skin coupler that allows multiple fingers to be placed over the LED. [Figure 35A] FIG. 35A illustrates an example of skin bonding using a conformal coating, according to some embodiments. [Figure 35B] FIG. 35B illustrates an example of skin bonding using a conformal coating, according to some embodiments. [Figure 36A] FIG. 36A illustrates an example of how light can be emitted from an emitter to a patient's skin, according to some embodiments. [Figure 36B] FIG. 36B illustrates an example of a photodiode, a detector, and an epoxy bridge between them according to some embodiments. [Figure 36C] FIG. 36C shows a thicker bridge than that of FIG. 36A. [Figure 36D] FIG. 36D illustrates an example of a photodiode, a detector, and an epoxy bridge between them according to some embodiments. [Figure 36E] FIG. 36E shows a thicker bridge than that of FIG. 36A. [Figure 37A] FIG. 37A shows a first example of a skin-bonding example. [Figure 37B] FIG. 37B shows a second example of skin bonding. [Figure 37C] FIG. 37C shows a first example of a skin-bonding example. [Figure 37D] FIG. 37D shows a second example of skin bonding. [Figure 38A] FIG. 38A illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 38B] FIG. 38B illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 38C] FIG. 38C illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 39A]FIG. 39A illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 39B] FIG. 39B illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 39C] FIG. 39C illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 39D] FIG. 39D illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 40A] FIG. 40A illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 40B] FIG. 40B illustrates an example of an adhesive portion that mates with an electronic housing, according to some embodiments. [Figure 41] FIG. 41 shows graphs of ECG and PPG signals for determining PPT according to some embodiments. [Figure 42] FIG. 42 illustrates a graph for calculating PPT as an integral using R-peak information, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0061] The following description is directed to numerous different embodiments. However, the described embodiments can be implemented and / or varied in many different ways. For example, the described embodiments can be implemented in any suitable device, apparatus, or system for monitoring any of numerous physiological parameters. For example, the following discussion focuses primarily on long-term patch-type heart rate monitoring devices. In one alternative, the physiological monitoring device can be used, for example, for pulse oximetry or diagnosing obstructive sleep apnea. The manner in which the physiological monitoring device is used also varies. In some cases, the device may be worn for a week or less, while in other cases, the device may be worn for at least seven days and / or for more than seven days, e.g., 14 to 21 days or more. Many other alternatives and applications of the described technology are possible. Therefore, the following description is provided for illustrative purposes only. Throughout this specification, reference may be made to the term "conformal." As used herein, one skilled in the art will understand that the term "conformal" refers to the relationship between surfaces or structures in which a first surface or structure conforms to the contours of a second surface or structure.

[0062] Because abnormal cardiac rhythms and arrhythmias often have other, less serious causes, a key challenge is determining whether any of these symptoms are due to arrhythmias. In many cases, arrhythmias occur infrequently and / or episodically, making a rapid and reliable diagnosis difficult. As mentioned above, cardiac rhythm monitoring is currently achieved primarily through the use of short-term (less than one day) electrodes attached to the chest, such as Holter monitors. The electrodes are connected to a recording device by wires, typically worn on a belt. The electrodes must be replaced daily, and the wires are cumbersome. Additionally, the devices have limited memory and recording time. Wearing the device impedes patient movement, often preventing certain activities while the device is in use, such as bathing. Furthermore, Holter monitors are capital equipment and have limited availability, often leading to supply constraints and associated testing delays. These limitations significantly hinder the device's diagnostic utility, patient compliance with the device, and the ability to capture all important information. Lack of adaptability and device shortcomings often lead to the need for additional devices, follow-up monitoring, or other tests to make a correct diagnosis.

[0063] Current methods for correlating symptoms with the occurrence of arrhythmias, including the use of cardiac rhythm monitoring devices such as Holter monitors and cardiac event recorders, are often insufficient to make an accurate diagnosis. In fact, Holter monitors have been shown to be nondiagnostic 90% of the time (D.E. Ward et al., "Assessment of the Diagnostic Value of 24-Hour Ambulatory Electrocardiographic Monitoring," Biotelemetry Patient Monitoring, vol. 7, published in 1980).

[0064] Furthermore, the medical process of actually obtaining a heart rate monitoring device and initiating monitoring is typically very complicated. There are typically numerous steps involved in ordering, tracking, monitoring, retrieving, and analyzing the data. Currently, heart monitoring devices are almost always ordered by cardiologists or cardiac electrophysiologists (EPs) rather than the patient's primary care physician (PCP). This is important because PCPs are often the first to see a patient and determine whether their symptoms may be due to arrhythmia. After a patient visits a PCP, the PCP schedules an appointment with the cardiologist or EP. This appointment typically occurs several weeks after the initial PCP visit, which can lead to a delayed diagnosis and potentially undiagnosed arrhythmia episodes. When a patient finally sees a cardiologist or EP, a heart rate monitoring device is usually ordered. The monitoring period lasts 24–48 hours (Holter monitor) or up to one month (cardiac event monitor or mobile telemetry device). Once monitoring is completed, the patient must typically return the device to the clinic. After the data is processed by the monitoring company or by technicians at the hospital or office, the report is finally sent to the cardiologist or EP for analysis. This complex process means that fewer patients receive heart rate monitoring than would be ideal.

[0065] To address some of these problems with cardiac monitoring, the assignee of the present application has developed various examples of small, long-term wearable physiological monitoring devices, such as the Zio® Patch developed and sold by iRhythm Technologies, Inc. Various examples of cardiac monitors developed and sold by iRhythm Technologies, Inc. are also disclosed in, for example, U.S. Patent Nos. 8,160,682, 8,244,335, 8,150,502, 8,560,046, 8,538,503, 9,241,649, 10,405,799, 10,517,500, 11,141,091, 10, 271,754, 10,555,683, 11,051,738, D852,965, D854,167, 9,173,670, 9,451,975, 9,597 ,004, 9,955,887, 10,098,559, 10,299,691, 10,667,712, 10,813,565, 11,289,197, 11,3 50,864, 11,350,865, 11,337,632, 11,246,523, 11,399,760, 11,246,524, 11,382,555, 11,083,371, 11,253,185, 11,253,186, and 11,375,941, the entire disclosures of which are incorporated herein by reference. Generally, the physiological patch monitors described in these documents are designed to be comfortably worn on the patient's chest and to be worn for at least one week, typically two to three weeks. The monitor continuously detects and records heart rate signal data while the device is worn, and this heart rate data is then available for processing and analysis.

[0066] These small, long-lasting patch-type physiological monitoring devices offer many advantages over prior art devices. At the same time, further improvements are desirable. One of the most significant improvements would be more timely notification of critical arrhythmias to the managing clinician. A characteristic of these early examples, for performance, compliance, and cost reasons, was that the device recorded information only during the extended wear period, with analysis and reporting occurring after recording ceased. Therefore, a desirable improvement would be to add the ability to analyze collected rhythm information in real time or in a timely manner. While diagnostic monitors with such timely reporting capabilities currently exist, they require periodic recharging or replacement of one or more electrical components of the system. These actions reduce patient compliance and ultimately diagnostic yield. Therefore, a key improvement would be to develop a physiological monitor capable of long-term recording and timely reporting without the need for battery charging or replacement.

[0067] Patient compliance and device adhesion are two factors that affect the duration of ECG recordings and, therefore, diagnostic outcomes. Compliance can be improved by improving patient comfort, which is influenced by wearing comfort, device appearance, and the extent to which the device interferes with normal daily activities. Given that longer ECG recordings increase diagnostic yield and therefore value, improving device wearability and patient compliance is desirable.

[0068] Signal quality is important throughout the wear period, but even more so when patients mark the recording to indicate areas of clinically significant symptoms. Marking the recording is most easily accomplished with a trigger located on the exterior of the device. However, because the trigger may be part of a skin-contact platform with built-in electrodes, significant motion artifacts may occur when the patient feels the trigger. A desirable device improvement would be a symptom trigger that can be activated with minimal motion artifacts.

[0069] Furthermore, it is desirable that the device be simple and cost-effective to manufacture, allowing for scalability in manufacturing and high quality through process reproducibility. Simplicity in manufacturing also translates into ease of disassembly, allowing for efficient recovery of quality-controlled printed circuit boards for reuse in other devices. Efficient recycling of this expensive component is critical to lowering the cost of diagnostic monitors.

[0070] However, there are clinical scenarios in which a longer-term, lower-cost solution would be a valuable addition to ambulatory cardiac monitoring portfolios. Hints at a potential solution to this need can be found in the continuous heart rate detection features increasingly being implemented in various consumer health and fitness products, such as smartwatches and wearable fitness bands. While continuous heart rate data can be used to provide information about a user's general fitness level, using this data to provide meaningful information related to the user's health and wellness is more challenging and valuable. For example, if potential arrhythmias could be detected from continuous heart rate data, consumer devices equipped with heart rate sensing could potentially serve as screening tools for the early detection of cardiac abnormalities. Such an approach could be clinically valuable in providing a long-term, cost-effective screening method for at-risk populations, such as heart failure patients at risk for atrial fibrillation. This monitoring approach could also be useful for adjusting therapeutic drug dosage over time while minimizing side effects in the treatment of paroxysmal atrial fibrillation. In addition to arrhythmia detection, appropriate analysis of heart rate information could potentially be applied to sleep and stress monitoring.

[0071] Long-term ambulatory monitoring using physiological devices such as adhesive patches has many clinical applications, especially if it can provide timely information on the occurrence and duration of arrhythmias observed during the monitoring period. Efficient detection of atrial fibrillation is a critical monitoring need, especially given its prevalence with an aging population. This need extends beyond symptomatic patients, and considering the increased risk of stroke associated with this arrhythmia, it is necessary to monitor asymptomatic atrial fibrillation on a broad population-based basis in individuals at risk due to factors such as advanced age, the presence of chronic conditions such as heart disease, or prior surgical procedures. In the latter case, perioperative and postoperative monitoring can be clinically valuable not only during arrhythmia prevention procedures (e.g., MAZE ablation and hybrid endomyocardial-epicardial therapy, both of which treat atrial fibrillation) but also during general surgery involving anesthesia. The purpose of ambulatory monitoring of atrial fibrillation can sometimes be reduced to a simple binary yes or no question: whether atrial fibrillation occurred during a given period. For example, monitoring patients after ablation procedures typically seeks to confirm success, defined as the complete absence of atrial fibrillation. Similarly, monitoring of patients after stroke is primarily concerned with assessing the presence of atrial fibrillation.

[0072] However, even in such scenarios, if atrial fibrillation occurs, it may be clinically meaningful to assess the daily burden (percentage of time spent in atrial fibrillation per day) and episode duration (e.g., expressed as a histogram of episode duration or as the percentage of episodes exceeding a certain limit, such as 6 minutes) to better characterize its occurrence, either in absolute terms or in comparison with a previous benchmark (e.g., using a baseline pre-procedure monitoring result). Indeed, measuring the daily burden of atrial fibrillation, assessing atrial fibrillation episode duration, considering the occurrence of atrial fibrillation during sleep and waking, and assessing the presence of atrial fibrillation in response to the patient's degree of physical exertion are important in various clinical scenarios, including evaluating the effectiveness of drug-based treatments for this arrhythmia.

[0073] Having this information available in a timely manner during the monitoring period would allow the managing physician to iteratively titrate therapy until management is optimized, for example, by adjusting the dose or frequency of a novel oral anticoagulant (NOAC).A further example of this management paradigm is when patients are notified of asymptomatic AF—either directly from the device via an audible or vibration-based alert, from an application connected to the device, or by communication from the managing clinician via phone, email, or text message—enabling timely application of a “medicine in the pocket” approach for AF management.

[0074] In situations where clinically significant arrhythmias are observed, such as asymptomatic second-degree or complete heart block, prolonged pauses, high-rate supraventricular tachycardia, prolonged ventricular tachycardia, or ventricular fibrillation, the theme of timely management and / or intervention is certainly evident. For example, the clinical scenario in which prolonged pauses or complete heart block precipitate syncope is a particularly important case, where the availability of timely and reliable monitoring methods could reduce or eliminate the need for in-hospital monitoring in at-risk patients. This theme also extends to more subtle morphological changes, such as drug-induced QT prolongation, which has been shown to have significant cardiac safety implications. Timely recognition of such prolongation could, for example, lead to early termination of clinical trials evaluating the safety and efficacy of a drug or to adjustments in dosage or frequency as a means of eliminating the observed prolongation.

[0075] Physiological Monitoring Devices 1A-1B show multiple views of a non-limiting example of a physiological monitoring device 100. Additional details of the physiological monitoring device 100 are disclosed in U.S. Pat. No. 11,337,632, which is incorporated herein by reference in its entirety for all purposes. The physiological monitoring device 100 may include one or more of the components described elsewhere herein. The physiological monitoring device 100 may include a housing 115 including an upper housing 140 and a lower housing 145 configured to fit together, sandwiching a flexible body 110 therebetween. The flexible body 110 may include a trace layer and one or more substrate layers that form wings of the physiological monitoring device 100. The wings may include adhesive layers and electrodes, as described elsewhere herein. The rigid body and / or housing 115 may enclose the PCBA 120 , the flexible upper housing 140 , the battery 160 , the battery terminal connector 150 , a portion of the trace layer, the spring contact spacers 132 , and the springs 165 .

[0076] Figure 1A is a perspective view of an example physiological monitoring device 100. Figure 1B shows an exploded view of physiological monitoring device 100.

[0077] The upper housing 140 and the lower housing 145 can sandwich the flexible body 110, as described elsewhere herein. In some embodiments, the flexible body 110 can include one or more apertures 138 extending through one or more of the substrate layers to provide breathability and moisture management and / or facilitate drug delivery to the surface skin, as described elsewhere herein. Upper and / or lower gasket layers (not shown) can be provided on opposite sides of the flexible body 110. The gasket layers can be adhesive for adhering to the flexible body 110. A compressible seal can be formed above and / or below the flexible body 110. In some embodiments, the compressible seal can be formed in the upper housing 140. The upper housing 140 can be a flexible frame. The battery 160 can be positioned below the flexible body 110, which comprises a trace layer. The PCBA 120 can be positioned above the flexible body 110, which comprises a trace layer. The battery terminal connector 150 may be glued or otherwise coupled to the battery 160 such that first and second battery traces (not shown) are exposed on the outer surface of the battery terminal connector 150 on the upper side of the battery 160. The first and second battery traces may be exposed to the interior volume of the upper housing 140 through a large central opening in the housing area of ​​the trace layer.

[0078] Electrical contact between the PCBA 120 and the first and second battery traces, and / or between the PCBA 120 and the ECG interface portions of the electrical traces 111, 112, may be established by spring contacts. The spring contacts may be coupled to a bottom surface of the PCBA 120. The housing 115 may include a spring contact spacer 132 disposed below the PCBA 120. In some examples, the spring contact spacer 132 may be rigidly affixed (e.g., glued) to the bottom surface of the PCBA 120. In some examples, the spring contact spacer is attached to or integrated with the flexible body 110. In some examples, the spring contact spacer may be integrated into the battery terminal connector. The spring contact spacer 132 may include a flat body and a plurality of downwardly extending legs 133. The legs 133 can be configured to seat against the top and / or sides of the battery 160 so that the spring contact spacer 132 maintains a minimum separation distance between the battery 160 and the PCBA 120 and provides sufficient space for the spring contacts. The spring contact spacer 132 may include one or more holes through which the spring contacts can extend downward from the bottom surface of the PCBA 120. The lower housing 145 can include a spring 165 disposed below the battery 160, as described elsewhere herein. The spring 165 can bias the battery 160 upward, biasing the first and second battery traces into physical and electrical contact with the corresponding spring contacts. The ECG interface portions of the traces 111, 112 can seat against the top surface of the battery 160 so that biasing the battery 160 upward also places the ECG interface portions of the traces 111, 112 in physical and electrical contact with the corresponding spring contacts. The substantially constant spacing between the traces and PCBA 120 provided by springs 165 and spring contact spacers 132 can reduce, minimize, or eliminate noise in the electrical signal caused by variations in the degree of electrical contact between the spring contacts and the traces.The assembly may include at least one spring contact for each of the first battery trace, the second battery trace, the first electrical trace 111, and the second electrical trace 112. The assembly may include multiple spring contacts for some or all of the traces. The spring contacts may be configured to establish an electrical path between each trace and the PCBA 120 under compression induced by the arrangement of various components, including the spring 165. The compressive contact between the spring contact and the trace may be maintained even under small nominal changes in the separation distance between the trace and the PCBA 120 (e.g., caused by movement) because the spring contact extends further downward when the separation distance increases and the biasing force decreases. In some examples, the first and second battery traces may be configured to be located on opposite sides of the housing 115 from the first and second electrical traces 111, 112. In some examples, the spring contacts may be configured to transmit electrical signals or electrocardiogram signals from the battery by contacting electrical traces applied to the upper housing 140 or the lower housing 145. These electrical traces may be applied to the housing through the use of laser direct structuring, plating onto a plateable substrate applied in a secondary forming process, or printing by aerosol jet, inkjet, or screen printing of conductive materials. In some examples, an RF antenna for wireless communications (such as Bluetooth®) may be constructed by using such electrical traces on upper housing 140 or lower housing 145.

[0079] 2A-2D depict multiple views of an example of a physiological monitoring device 200 similar to the physiological monitoring device depicted in FIGS. 1A-1B. Here, the physiological monitoring device includes a central housing 202 including an upper housing 204 and a lower housing 206 sandwiched on a flexible substrate. Those skilled in the art will appreciate that the housing may be constructed from any suitable material disclosed herein, such as a rigid polymer or a soft, flexible polymer. In some examples, the housing may include an indicator 208 that is any suitable shape, such as an oval, circle, square, or rectangle. The indicator may include an LED light source (not shown) or any suitable light source and may be overlaid with a transparent or translucent viewing layer disposed against the inner surface of the upper housing. The viewing layer may be constructed from thermoplastic polyurethane or any suitable material. The indicator may be used to indicate the status of the physiological monitoring device, such as the battery life of the physiological monitoring device. In some examples, the indicator may indicate whether the physiological monitoring device is collecting data, transmitting data, pausing, experiencing an error, analyzing data, etc. The indicator may display any suitable color, such as red, amber, green, etc.

[0080] Extending outwardly from the housing are a plurality of wings 212. While two wings are depicted here, one skilled in the art will understand that some embodiments of the physiological monitoring device 200 may include more than two wings. As described elsewhere herein, the wings may be shaped to improve adhesion to and retention of the physiological monitoring device against the skin. In an example, the wings may be asymmetric, with a majority of one wing (upper lobe) 214 lying above the longitudinal line and a majority of another wing (lower lobe) 216 lying below the longitudinal line, thereby allowing the physiological monitoring device to be positioned at an angle above the heart such that the lower lobe is positioned below the heart when the patient is in a standing position.

[0081] Extending outward from the housing and contained on or within the wings are electrode traces 218, similar to those described elsewhere herein, such as in FIG. 1A . As described elsewhere herein, the electrode traces can be printed directly onto a flexible substrate that is part of a multilayer flexible assembly 220. Additional printed lines 222 can surround the electrode traces 218 to enhance the visual appearance of the physiological monitoring device, but the printed lines 222 can be printed on a different layer of the flexible substrate than the one on which the electrode traces are printed. The printed lines can be printed to match the shape of the electrode traces. As described elsewhere herein, the electrode traces can surround a series of ventilation holes 224 that allow air to pass through to the underlying hydrogel. In examples, there may be one, two, three, four, or more ventilation holes. As described elsewhere herein, openings 232 can extend through one or more layers of the physiological monitoring device to provide breathability and moisture management. In an embodiment, an adhesive boundary layer 228 may extend outward from the wings, thereby improving adhesion. FIG. 2B depicts the underside of the physiological monitoring device 200 depicted in FIG. 2A. Here, the lower housing 206 is clearly visible, as are the electrode traces 218 and printed lines 222 extending outward from the housing. FIGS. 2C and 2D depict the physiological monitoring device 200 of FIGS. 2A-2B, now including an exterior-facing top liner 226 and a skin-facing patient release liner 230 that overlie the wings and surround the central housing 202. Such a release liner serves to protect the physiological monitoring device 200 during storage, particularly the adhesive surface of the physiological monitoring device. In an embodiment, the liner can be shaped so that two sides meet to form an opening for the housing to extend perpendicularly beyond the liner.

[0082] In some embodiments, an abrader can be used to abrade the patient's skin before adhering the physiological monitoring device 200 (as described elsewhere herein) to the patient. The abrader can be used to remove a superficial layer of skin from the patient to improve long-term adhesion of the physiological monitoring device and / or signal quality of the physiological monitoring device.

[0083] In various alternative embodiments, the shape of a particular physiological monitoring device may vary. The shape, footprint, perimeter, or boundary of the device may be, for example, circular, elliptical, triangular, compound curve, etc. In some examples, the compound curve may include one or more concave curves and one or more convex curves. The convex shape may be separated by a concave portion. The concave portion may be between a convex portion on the housing and a convex portion on the electrode. In some examples, the concave portion may correspond at least in part to a hinge, hinge region, or region of reduced thickness between the body and the wing.

[0084] Although described in the context of a cardiac monitor, the device improvements described herein are not so limited. The improvements described herein may be applied to any of a wide variety of physiological data monitoring, recording, and / or transmission devices. The improved adhesive design features may also be applied to devices useful for electronically controlling and / or time-release delivery of pharmacological agents or blood tests, such as glucose monitors and other blood testing devices. As such, the component descriptions, characteristics, and functions described herein may be modified as needed to include specific components for a particular application, such as electronics, antennas, power or charging connections, data ports, or connections for downloading or offloading information from the device, adding or offloading fluids from the device, monitoring or sensing elements such as electrodes, probes, or sensors, or other components or components required for the device's unique functionality. Additionally or alternatively, the devices described herein may be used to detect, record, or transmit signals or information related to signals generated by the body, including, but not limited to, one or more of ECG, EEG, and / or EMG. In certain examples, additional data channels may be included to collect additional data such as, for example, device movement, device flexion or bed, heart rate and / or ambient electrical or acoustic noise.

[0085] The physiological monitors described above and elsewhere herein can be further combined with data processing and transmission methods and systems that improve data collection from the monitor. Additionally, the methods and systems described below can improve monitor performance by enabling timely transmission of clinical information while maintaining the high patient compliance and ease of use of the monitors described above. For example, the data processing and transmission methods and systems described in this section or elsewhere herein can serve to extend the monitor's battery life, improve the monitor's accuracy, and / or provide other improvements and advantages described in this section or elsewhere herein.

[0086] 3A-3H illustrate an example of a physiological monitoring device 300 similar to that depicted in U.S. Pat. No. 11,350,864, which is incorporated by reference in its entirety. FIG. 3A illustrates a perspective view of the physiological monitoring device. The physiological monitoring device 300 may include wings 330, 331, each of which is asymmetrical about a longitudinal axis extending generally between an electrode interface portion 302 that covers an electrode disposed on the underside of the wing. Electrode traces 304 extend from the housing to the electrode, providing electrical communication between the electrode and the central housing. One wing 330 includes a body disproportionately positioned above the longitudinal axis, while the other wing 331 includes a body disproportionately positioned below the longitudinal axis. Thus, wings 330, 331 can make the flexible body asymmetrical about a transverse axis extending through housing 306, perpendicular to the longitudinal axis, which can include patient trigger 307, as well as other patient triggers disclosed in this section or elsewhere herein. As described elsewhere herein, in certain embodiments, the patient trigger occupies 10-30% of the total top area, e.g., about 20% of the total top area or about 23%, such as about 22.8% of the total top area. In certain examples, the patient trigger can encompass about 20% or more, about 30% or more, about 40% or more, about 50% or more, or about 75% or more. In some embodiments, the patient trigger can occupy the entire top surface of the housing. Wings 330, 331 can be comprised of the same shape reversed or inverted about both the longitudinal and transverse axes, as shown in FIGS. 3A-3C. In some embodiments, the wings may be asymmetrical in size or shape, for example, upper wing 330 may be larger than lower wing 331, or vice versa. The shapes of wings 330, 331 may also be different, such that the relative shape of upper wing 330 differs from the relative shape of lower wing 331. In certain examples, upper wing 330 may be subjected to greater tension than lower wing 331, or vice versa, and thus the different size and shape between the two wings may help address unique force vectors during use of the physiological monitoring device.The wing configuration is particularly suited to positioning electrodes diagonally relative to the subject's height, potentially reducing gravity-induced delamination. Those skilled in the art will appreciate that the orientation of the wings may be altered so that, rather than being disproportionately positioned above or below the longitudinal axis, the wings are positioned in a mirror image. Furthermore, those skilled in the art will appreciate that the shape of the wings as described herein may differ from the generally rounded shapes depicted in FIGS. 3A-3H. For example, the wings may be angular, such as square, rectangular, triangular, pentagonal, or any suitable polygonal shape. These polygonal shapes may have rounded corners to reduce the likelihood of delamination at the corners. A liner 308, as depicted elsewhere herein, may be used to cover and protect any adhesive prior to application of the physiological monitoring device to a patient or user. In an example, the liner may be separated into two pieces, one on each wing.

[0087] In certain embodiments, an additional visualization pattern 310 may extend through the wings. The visualization pattern 310 may be any suitable size or shape to outline the electrode traces and frame the shape of the wings. For example, the visualization pattern 310 may be in the form of lines, such as rounded lines, to reflect the outline of the electrode traces and the shape of the wings. In certain examples, the lines may be one, two, three, four, or more. In some embodiments, the visualization pattern may be formed from a pattern of dots, shapes, or other combinations to maintain the visual cleanliness of the device even in situations where an otherwise transparent adhesive layer becomes less visually acceptable to the user over the course of wear (e.g., if the adhesive layer picks up foreign matter and / or becomes cloudy due to moisture absorption). In certain embodiments, the visualization pattern may have another functional purpose of informing the user how long the device has been worn, for example, by changing color over time or with wear. Such a change in appearance can alert the user to remove the device at the appropriate time. FIG. 3B shows a top view, FIG. 3C shows a bottom view, and FIG. 3D1 shows a side view of an example physiological device 300. In FIG. 3C, flexible electrodes 312 are visible. As shown in FIG. 3D1, upper and lower housing 314 and 316 portions of the housing can be positioned above and below a flexible body 318. FIGS. 3E and 3F show the underside and top side of the physiological monitoring device 300, with each layer transparent so that all layers are visible. Each layer is described in more detail below in an exploded view of the physiological monitoring device 300. An opening 320 can be disposed in a substrate layer disposed above the adhesive layer. As described in more detail above, such an opening can provide ventilation through one or more layers and facilitate evaporation of moisture from below the adhesive layer through the layer or layers comprising the opening. In some embodiments, a gasket 319 can be disposed between the upper and lower housings 314 and 316, which are co-molded to one or more of the housings, as shown in FIG. 3D2.The gasket can compress the adhesive assembly and raised interface (shown below in FIG. 3D2) or another gasket on the opposing housing to provide waterproofing to the internal electronic hardware. As depicted in FIG. 3B2, a ridge 321 can be disposed on the upper edge of the lower housing 316, configured to press against the adhesive layer 336. Those skilled in the art will appreciate that the ridge 321 can be any suitable shape, such as a bordered ridge as depicted in FIG. 321. In certain embodiments, the ridge can be rounded, rectangular, and / or polygonal. In certain examples, the ridge height can be about 0.15 mm, such as about 0.01 mm to 0.5 mm, about 0.05 mm to 0.4 mm, about 0.1 mm to 0.3 mm, about 0.1 mm to 0.2 mm, or about 0.13 mm.

[0088] FIG. 3G shows an exploded view of an example flexible body 301 of a physiological monitoring device 300 described herein and elsewhere herein. The housing 306 is not shown. As will be understood by those skilled in the art, the image in FIG. 3G is oriented upside down with respect to positioning on the skin. According to the numbering in FIG. 3G, #7 depicts a release liner protecting the adhesive layer 340 and the hydrogel electrodes 350. Directly above the adhesive layer is a perforated layer 344 (including openings as described herein) and a flap layer 303. In certain examples, the perforated layer and flap layer may be composed of any suitable material, such as polyethylene terephthalate (PET) and / or polyurethane. Directly above the perforated layer may be a lower substrate layer #1, which may be composed of polyurethane. In embodiments, the lower substrate layer may have at least one textured side, which may be positioned so that the textured side faces the flap layer #3. In embodiments, the flap layer #3 may also include at least a textured side. This textured side can be configured to face the bottom substrate layer #1. The conductive electrode traces can be printed on an additional separate substrate (311, 312). Alternatively, in some examples, the conductive electrode traces may be printed directly on substrate layer #1. Located above the conductive electrode traces is a top substrate layer 334. Located above the top substrate layer is an additional carrier layer #10, followed by an adhesive layer #11 and a top rigid liner #9. One skilled in the art will understand that this layer arrangement is applicable to any example of a physiological monitor described herein, such as the examples of Figures 3A-3F.

[0089] FIG. 3H shows an exploded view of an example housing 306 of a physiological monitoring device 300, through which the flexible body 301, described in detail above, passes. An upper housing cover 314 can include a patient trigger 307. Additionally, the upper housing cover 314 can encase a circuit board 322. A spacer 323 disposed on the underside of the circuit board is configured to maintain a constant spacing between the conductive contact springs on the underside of the circuit board and the battery terminal / ECG trace contacts. The spacer can also provide electrical insulation between the circuit board and the battery. The spacer has holes for the conductive contact springs to pass through, and the contact springs are connected to the circuit board. A battery terminal 325 can be disposed below the flexible body 301 and circuit board 322, thereby resting on a wave spring 326. In an embodiment, the battery terminal 325 can be wrapped around and glued to a coin cell battery 328. The battery terminals 325 can be configured as a flex circuit with conductive vias 327, which elevates the bottom positive surface of the coin battery 328 to the top negative surface of the battery, exposing both the negative and positive terminals to the top surface of the battery for mating with contact springs on the circuit board. Alternatively, battery contacts on the bottom housing can elevate the bottom positive surface of the coin battery to the top negative surface for contact with the circuit board. The vent layer 329 can be positioned relative to the bottom housing 316, over the vent holes 332 in the bottom housing. In embodiments, the vent layer can be constructed from a material that allows the passage of gases while preventing the passage of liquids, such as ePTFE or any other suitable material. The combination of the vent holes 332 and the vent layer allows for normalization of air pressure between the exterior and interior of the housing. In embodiments, the vent holes 332 in combination with the vent layer prevent the button and / or trigger 307 from being blown out or sucked in depending on the external air pressure, for example, when a patient is at different altitudes, such as on an airplane. The ventilation layer may be thin and round with a ring of adhesive on the bottom surface. The adhesive-covered area of ​​the ventilation layer may be gas impermeable, while the center portion may be gas permeable but liquid impermeable.A central portion of the vent layer can be positioned over the vent hole, thereby allowing gas to enter and exit the housing while restricting liquid from entering and exiting. In some embodiments, the vent layer can be molded integrally into the bottom housing, ultrasonically welded to the bottom housing, or adhered by any suitable means.

[0090] Physiological Monitoring Devices Referring now to the example of FIG. 4 , an illustrative perspective view of a sensor platform 1050 is provided, according to one embodiment. In some examples, ECG and / or PPG sensor platform components may include hardware 1052 and software 1054 aspects of the sensor platform. In some examples, the hardware aspects of the sensor platform may include an ECG and / or PPG sensor 1056 and a blood pressure reference 1058. In some examples, the blood pressure reference 1058 may measure patient data to be used as a reference for further blood pressure measurements. For example, a patient may measure their blood pressure using a blood pressure device and enter the blood pressure data into a wireless application, which the sensor platform 1050 can access and compare to the currently measured blood pressure for a baseline. Additionally, software components of the sensor platform may be used to perform diagnostic analyses using data collected from the hardware components. In some examples, the software components of the sensor platform may include filtering and peak detection 1060, pulse transit time (PTT) or pulse arrival time (PAT) calculation 1062, and regression analysis 1064. In some examples, a separate third-party system may be used for such calibration.

[0091] In an exemplary embodiment, filtering and peak detection 1060 may be the first step in preprocessing data collected from the sensor platform hardware. For example, filtering may include software-enabled filtering of the data, such as a bandpass filter, a Kalman filter, or another equivalent filtering process. Peak detection may include software-enabled identification of maximum or minimum values ​​from the ECG and / or PPG sensors. PAT calculation 1062 may include peaks identified from the peak detection process and use both the ECG and PPG sensor data to identify an estimated PAT for each heartbeat. Regression analysis 1064 may be a software-enabled trend prediction technique for correlating physiological signals from the sensor platform with hemodynamics and / or other characteristics of the user's blood flow or stroke volume. In some examples, the system may track changes in sensor values, blood pressure values, or the behavior of this correlation over time. The sensor platform may be configured to determine the regression analysis using a regression technique, such as a linear regression model, a nearest-neighbor regression model, a time-based regression, a multivariate regression, or any other suitable regression technique. The example in FIG. 4 is described in a certain order. However, it is understood that a different sequence or configuration of the software and hardware elements may be employed.

[0092] 5A, 5B, and 5C, an exemplary illustration of at least one embodiment is provided. In FIG. 5A, the exemplary diagram 1100 may include an overview of a device including a sensor platform 1102 (e.g., the sensor platform 1050 disclosed in FIG. 4) for collecting data and identifying physical or physiological characteristics of a user wearing the device. In one example, the sensor platform 1102 may be worn on the user's chest, as shown. In other examples, the sensor platform 1102 may be worn on other parts of the user's body. In some examples, the sensor platform 1102 may include at least one ECG sensor 1104 and at least one PPG sensor 1106. In some examples, the at least one ECG sensor 1104 and / or PPG sensor 1106 may be embedded in an adhesive patch that is in physical contact with the user. In some examples, there are multiple ECG sensors 1104 and / or multiple PPG sensors 1106.

[0093] In FIG. 5B , the exemplary diagram 1110 can include an example of the reflectivity of a PPG sensor 1106 on a device. In some examples, the PPG sensor 1106 can include an emitter 1106A and a detector 1106B. For example, the emitter 1106A and the detector 1106B each transmit wavelengths of the electromagnetic spectrum into a user's body and receive reflected wavelengths of the electromagnetic spectrum. In some examples, the system can evaluate the received signals to track the amount of light reflected back to the detector as modulated by pulsating blood flow through the user's blood vessels. The amount of tracked reflected light can correspond to hemodynamic information. In some examples, the difference in the wavelength spectrum between the transmitted and received signals of the electromagnetic spectrum can correspond to the physical properties of blood moving through the user's body and can further correspond to the quality or condition of the user's heart.

[0094] In FIG. 5C , an exemplary diagram 1120 may include an exemplary calculation of PAT, which may be correlated to a user's blood pressure. In some examples, PAT may be calculated based on data collected from the ECG sensor 1104 and the PPG sensor 1106. For example, the sensor platform 1102 may detect peaks from the ECG data from the ECG sensor 1104 and the PPG data from the PPG sensor 1106. The sensor platform 1102 may measure ECG p-waves, PPG valleys and / or troughs, inflection points along the systolic ascent, determine a weighted center of gravity for each pulse, and / or the like. The ECG data may correspond to the electrical signal for the heart to pump, and the PPG data may correspond to the mechanical pumping action of the heart. A measurement of the difference between the peaks from the ECG signal and the PPG signal generally corresponds to the PAT. The value of the PAT may correspond to the user's blood pressure. The PAT may be inversely proportional to the user's blood pressure. In some examples, the sensor platform 1102 may measure the time between peaks identified in the ECG data and the PPG data to calculate the PAT. In some examples, the left axis of the diagram may include ECG values ​​from the ECG measurements 1122, and the right axis may include PPG values ​​from the PPG measurements 1124. The detected peaks for each of the sensors may result in calculating an estimated blood pressure.

[0095] Referring now to the example of FIG. 6 , this example provides a schematic diagram of a device 1200 according to one embodiment. This example may be similar to the example described above in FIGS. 1-5 , including in some aspects. In some examples, the device 1200 may include at least one photoplethysmography (PPG) sensor 1202, flexible optical electrode traces 1204 coupled to a microprocessor 1206, and at least one ECG sensor 1208. In certain examples, such a device may capture one or more ECG signals and one or more PPG signals to provide comprehensive health information. Similar to FIGS. 1-5 above, the wings may be flexible and provide conformal contact with the subject's skin, which may prevent the at least one PPG sensor 1202 from peeling or lifting off the skin, thereby providing strong motion artifact rejection and better signal quality by minimizing the transfer of stress to the at least one PPG sensor 1202. Additionally, in some examples, device 1200 can include a flexible body (e.g., flexible body 110 of FIG. 1A) arranged in a configuration having various features that facilitate comfortable wearing of device 1200 by the patient for 14 days or more without removal.

[0096] In some examples, the PPG sensor 1202 may include at least one light-emitting diode (LED) (such as LED 1202A) and a photodiode (PD) (such as PD 1202B). Thus, the LED 1202A and the PD 1202B may collectively be referred to as the PPG sensor 1202. The at least one LED 1202A may illuminate an area of ​​the user where the device 1200 is placed, such that signals received on the PD provide information regarding physiological characteristics of the user's body or blood flow.

[0097] In some examples, the system may include multiple LEDs. For example, one of the LEDs 1202A may illuminate the user's body with infrared light, and another LED (not shown) may illuminate the user's body with red light, and the PD may be able to sense reflected light from the user's body for both the infrared and red light. In some examples, the system may include one or more LEDs that emit light and one or more photodiodes that detect the light.

[0098] In certain examples, the reflected light (e.g., reflected light from infrared, green, red, or other light) may correspond to the user's oxygen saturation, heart rate, respiration, and / or blood pressure. The user's oxygen saturation can be derived by using dual-wavelength PPG, in which the two wavelengths are in different portions of the hemoglobin absorption spectrum. In some examples, one wavelength of light may be absorbed to a greater extent by oxyhemoglobin compared to deoxyhemoglobin, and another wavelength of light may be absorbed to a greater extent by deoxyhemoglobin than oxyhemoglobin. Additionally, certain wavelengths of light may be absorbed equally by oxyhemoglobin and deoxyhemoglobin. Being able to measure the user's oxygen saturation can be applied to monitoring sleep apnea and other respiratory disorders. In some examples, the ECG sensor 1208, microprocessor 1206, or other processor can convert the reflected light from an analog signal to a digital value. The ECG sensor 1208 can transmit analog or digital values ​​to the microprocessor 1206 via the flexible optical electrode traces 1204. In some examples, the PPG sensor 1202 can convert reflected light from an analog signal to a digital value. The PPG sensor 1202 can transmit analog or digital values ​​to the microprocessor 1206 via the flexible optical electrode traces 1204. In another example, at least one LED 1202A and / or PD 1202B can be subject to power constraints for long-term wear by a user. For example, at least one LED 1202A and / or PD 1202B can be subject to power constraints such that the device 1200 can be worn by a user for 14 days or more without being removed.

[0099] In some examples, the PPG sensor 1202 can maintain contact with the user at all times while collecting data. For example, a PPG sensor 1202 coupled to adhesive wings of a patch (e.g., flexible body 110 of FIG. 1A ) can maintain sufficient contact to obtain PPG data. In some examples, the PPG sensor 1202 can measure data from the user's chest. A PPG sensor 1202 coupled to adhesive wings of a patch can provide sufficient optical coupling to the PPG sensor 1202. In other examples, the device 1200 is agnostic to placement on the user. In some embodiments, the PPG sensor 1202 can be located on the underside of a housing that includes the microprocessor 1206. The PPG sensor 1202 in this embodiment may or may not maintain constant contact with the user's skin. The PPG sensor 1202 and / or the device in this embodiment may or may not include an adhesive coupling component.

[0100] In some examples, the microprocessor 1206 can receive digital values ​​determined by the PPG sensor 1202. In other examples, the microprocessor 1206 can receive an analog signal containing information about reflected light from the user's body via the flexible optical electrode traces 1204. In some examples, the microprocessor 1206 can combine values ​​from the PPG sensor 1202 with values ​​from the ECG sensor 1208. In some examples, the ECG sensor 1208 and the PPG sensor 1202 can collect data simultaneously and simultaneously transmit data values ​​to the microprocessor 1206. When the microprocessor 1206 combines the values, the result can be used to calculate the user's blood pressure. In some examples, the microprocessor 1206 calculates physical parameters from the data. For example, the microprocessor 1206 can calculate blood pressure based on the relationship between the peak values ​​of the PPG digital values ​​and the ECG digital values. The relationship between the peak values ​​may correspond to pulse arrival time (PAT). For example, the microprocessor 1206 can detect peaks from the ECG data from the ECG sensor 1208 and the PPG data from the PPG sensor 1202. The ECG data may correspond to the electrical signal for the heart to pump, and the PPG data may correspond to the mechanical pumping action of the heart. The measured difference between the peaks from the ECG signal and the PPG signal generally corresponds to the PAT. The value of the PAT may correspond to the user's blood pressure. The PAT may be inversely proportional to the user's blood pressure. In some examples, the microprocessor 1206 can measure the time between the identified peaks in the ECG data and the PPG data to calculate the PAT. In another example, the microprocessor 1206 can transmit the data collected from the ECG sensor 1208 and the PPG sensor 1202 to a computer or server for further processing. In another example, the data (and / or derived signals) from the ECG sensor 1208 and the PPG sensor 1202 can be downloaded from the microprocessor 1206 and uploaded to a computer or server for further processing.For example, the microprocessor 1206 can determine the peaks and the computer or server can determine the user's blood pressure.

[0101] In some examples, processing of data from the ECG sensor 1208 and the PPG sensor 1202 may include filtering and peak detection, calculation of PAT, and regression analysis. In one example, the microprocessor 1206 may filter the digital signals from the ECG sensor 1208 and the PPG sensor 1202 using a high-pass filter or another type of filtering method. In another example, the microprocessor 1206 may calculate PAT using the relationship between the data collected from the ECG sensor 1208 and the data collected from the PPG sensor 1202, or using the relationship between multiple PPG sensors. In some examples, the relationship between the PAT metric and blood pressure may be inversely correlated. In another example, the microprocessor 1206, computer, or server may calculate a regression trend of the data collected from the ECG sensor 1208 and the PPG sensor with a physiological metric, such as blood pressure. The regression trend may be calculated based on linear regression or any other regression analysis technique. In some examples, the microprocessor 1206, computer, or server can use regression analysis to later estimate blood pressure values ​​directly from the ECG and / or PPG sensors.

[0102] Typical PAT measurements from ECG and PPG sensors use sensors that are physically separated across a patient's body. For example, an ECG sensor is placed on the patient's chest, and a PPG sensor is placed on a user's finger. This disclosure describes examples that enable PAT measurements from ECG and PPG sensors that are placed in close proximity to one another. For example, the ECG and PPG sensors can both be on a device located on the patient's chest. A wearable device and / or other computing device can determine the delay between the ECG and PPG. Such delay can be correlated to the user's blood pressure. For example, an ECG signal can include an electrical signal that instructs the heart to beat, while a PPG can include a mechanical signal of the physical pumping of blood through blood vessels. There is an inherent delay between these two signals (because electrical signals propagate faster than mechanical signals).

[0103] In some examples, the ECG sensor 1208 and the PPG sensor 1202 can be proximate to each other without one of the sensors being positioned on the user's extremities. For example, the ECG sensor 1208 and the PPG sensor 1202 can be positioned on the user's chest to provide data collection solely from the chest location. In some examples, the ECG sensor 1208 and the PPG sensor 1202 collect data from blood vessels. The wearable device is configured to measure voltage potentials via electrodes in the heart's electrical pathways, including the sinoatrial node and / or the atrioventricular node. Additionally, the PPG sensor 1202 can collect data from arteries, veins, and / or capillaries.

[0104] The example of FIG. 7 provides a schematic diagram of a device 1300 according to one embodiment. In some embodiments, the device 1300 can include a flexible patch 1302 having a PPG sensor 1304 and a flexible optical electrode cable 1306. One advantage is that coupling the PPG sensor 1304 to the flexible patch 1302 increases user comfort. Another advantage of integrating the optics directly into the adhesive is improving the coupling between the optical sensor and the skin, resulting in improved PPG signal quality. In certain embodiments, coupling the PPG sensor 1304 to the flexible patch 1302 can allow the user to wear the device 1300 for extended periods of time without discomfort. In some embodiments, the flexible patch 1302 can include a silicone adhesive material to allow the device 1300 to be coupled to the user's body.

[0105] In some examples, the wearable device may include an impedance sensor (not shown). The impedance sensor may include an electrical sensor. In some examples, the impedance sensor and the ECG sensor may use different electrodes and / or share at least a subset of the electrodes. The impedance sensor may be used to mitigate noise from collected analog signals (e.g., when the impedance sensor is used to detect movement) and improve the accuracy of data collection measurements. The impedance sensor may also, or alternatively, be used in impedance cardiography (ICG) to measure changes in torso electrical conductivity and / or torso activity to derive cardiac parameters, including stroke volume and / or aortic valve opening time. The aortic valve opening time may help improve the accuracy of PAT metrics in estimating blood pressure.

[0106] In some examples, the small size of the PPG sensor 1304 generally helps provide conformal contact with the subject's skin, and the flexible electrode cable 1306 helps prevent the PPG sensor 1304 from peeling or lifting off the skin by keeping the PPG sensor away from the microcontroller and other electronic components (e.g., battery, analog front end), thereby minimizing the transfer of stress to the PPG sensor 1304, which can provide strong motion artifact rejection and better signal quality. Additionally, the device 1300 can include configurations and various features that facilitate comfortable wearing of the device 1300 by the patient for 14 days or more without removal. Elements of the device 1300 further allow the flexible patch 1302 to flex freely. The flexible optical electrode cable 1306 can also be thin and flexible to allow for patient movement without signal distortion.

[0107] Referring now to the embodiment of FIG. 8 , a schematic diagram of an optical sensor 800 according to one embodiment is provided. In some embodiments, the optical sensor 800 can include at least one LED 1402, at least one photodiode (PD) 1404, a capacitor location 802, a flexible printed circuit (FPC) cable 804, and a cable end 806. A significant advantage is reducing the form factor of a device (e.g., device 1300 of FIG. 7 ) while improving the device's functionality. In one embodiment, the at least one LED 1402 can include LEDs of a single color or various colors. For example, the at least one LED 1402 can include a green LED with a wavelength of 525 nanometers. In another example, the PD 1404 can include a commercially available PD capable of detecting changes in visible light. In some examples, the distance between the at least one LED 1402 and the PD 1404 can depend on the wavelength of the at least one LED 1402. For example, the distance between the at least one LED 1402 and the PD 1404 can include less than 10 millimeters. In some examples, the distance between the at least one LED 1402 and the PD 1404 may depend on the desired penetration depth of light into the skin or body. In certain embodiments, the light sensor 800 may include a capacitor at capacitor location 802. The capacitor may be used to isolate noise caused by other electrical circuits that may be picked up along a long FPC cable from the analog signal of interest. In other embodiments, the light sensor 800 does not have a capacitor at capacitor location 802. In some embodiments, the flexible printed circuit cable 804 may be an optical cable that allows electrical signals to travel from the at least one LED 1402 and the PD 1404 to an FPC connector into which the FPC cable end 806 is plugged.

[0108] Referring now to the example of FIG. 9 , an exemplary diagram of a user's blood pressure reference is provided, according to one embodiment. The diagram may further include a blood pressure graph 902 and a heart rate graph 904. Each of the graphs may include a first plurality of segments 906 representing a medium resistance workout. Each of the graphs may include a second plurality of segments 908 representing a difficult resistance workout. In some examples, a user's blood pressure measured using various measurement techniques may correspond to the user's heart rate during exercise. For example, when a user is exercising with a medium resistance band, the user's heart rate and blood pressure may correspond to a baseline for the medium activity. In another example, when a user is exercising with a difficult resistance band, the user's heart rate and blood pressure may correspond to a baseline for the difficult resistance. During each exercise period, the user's heart rate and blood pressure may be greater than the baseline determined when the user was at rest.

[0109] 10A and 10B, illustrations of exemplary graphs of a user's ECG data and PPG data are provided according to one embodiment. In some examples, a user may wear a device (e.g., device 1300 of FIG. 7) including a sensor platform including at least one ECG sensor and at least one PPG sensor. The sensor platform may collect data as the user performs various activities. Referring to the example of FIG. 10A, a first graph 1000 shows data collected from each of the ECG and PPG sensors, which may correspond to the physical properties of the user's heart, such as the electrical signals that pump the heart (i.e., ECG data) and the mechanical pumping action of the heart (i.e., PPG data). Referring to the example of FIG. 10B, a second graph 1010 shows the use of both ECG and PPG data, where the device can identify a first peak in ECG data 1012 and a second peak in PPG data 1014 at each heartbeat of the collected data. The peaks can then be used by the device (or in post-processing) to identify cardiac characteristics such as pulse arrival time (PAT) 1016 and estimate blood pressure.

[0110] Referring now to the example of FIG. 11 , an illustration of an exemplary graph of a user's PAT over time is provided, according to one embodiment. In some examples, PAT can be measured using a device (e.g., device 1300 of FIG. 7 ). In some embodiments, the device (or in post-processing) can cross-reference the PAT with the user's heart rate to determine the accuracy of the measurement. For example, PAT may be greatest when the heart rate is at a trough, and conversely, PAT may be lowest when the heart rate is at a peak.

[0111] Referring now to the example of FIG. 12A, FIG. 12A illustrates an example of electrodes for measuring impedance, i.e., electrical conductivity, across the thorax, according to one embodiment. The device can include a noninvasive sensor that measures electrical signals across the thorax. For example, the device can measure total electrical conductivity using inner measuring electrodes 1222 / 1224 and / or outer electrodes 1226 / 1228. The device can measure total electrical conductivity by driving a current between the outer electrodes 1226 / 1228 and measuring the voltage between the inner electrodes 1222 / 1224. FIG. 12A illustrates two inner electrodes 1222, 1224 and two outer electrodes 1226 / 1228. However, it is understood that the device can have only inner electrodes, only outer electrodes, a different number of electrodes, a different number of inner / outer electrode sets, and / or the like. The device can measure changes in electrical signals, such as total electrical conductivity, over time. The device can apply these measurements to derive cardiac parameters such as stroke volume, cardiac output, and pre-ejection period.

[0112] In some embodiments, a high-frequency, low-amplitude current (I) can be passed between electrodes (e.g., between two electrodes) across the chest. The electrodes can be positioned parallel to the spine. As a result, a voltage signal (V) can be recorded from the two electrodes. Impedance Z can be calculated from the current I and voltage V. For example, impedance Z can be calculated as Z=V / I. Electric currents typically seek the path of least resistance, which primarily includes the blood-filled aorta.

[0113] Referring now to the embodiment of FIG. 12B, FIG. 12B illustrates an example of electrodes and an ECG sensor for measuring electrical conductivity across the thorax, according to one embodiment. The device can include electrodes for impedance (such as two inner electrodes 1222 / 1224 and two outer electrodes 1226 / 1228) as well as for ECG (such as electrodes 1252 and 1254). The device can use sense electrodes that are shared with the ECG electrodes. The sensors can be configured for specific positions, angles, and / or minimum or maximum electrode separation. The signals emitted by the electrodes can be configured for specific amplitudes and / or frequencies.

[0114] In some examples, impedance can be used to utilize drive and sense electrodes. In a four-electrode configuration, there are two outer drive electrodes and two inner sense electrodes. In a two-electrode configuration, signals are driven and sensed from the same set of electrodes. In either configuration, the impedance sense electrode can be shared with the ECG sense electrode. Thus, the electrode configuration can include multiple electrodes, such as two, four, or six electrodes.

[0115] In some examples, impedance can be collected at a perpendicular vector (parallel to the up and down motion of the aorta). ECG can be collected at an angle (e.g., at a 45-degree angle) to measure above the heart. Impedance electrodes can be placed above and / or below the heart. ECG electrodes can be placed on the left and / or right side of the heart. For ECG data, electrodes can be spaced a greater distance above the heart to produce better signal quality. For impedance, a greater separation distance can also be applied while still remaining within the maximum distance at which the wearable device cannot resolve pulsatile waveforms from the heart.

[0116] In some cases, the input signal has preferred amplitude and frequency values ​​(e.g., an impedance drive signal of 32 kHz or higher, and a current of approximately 100 μA to 1.5 mA).

[0117] Referring now to the embodiment of FIG. 13A, FIG. 13A is a graph of an impedance electrocardiogram according to one embodiment. The device can derive impedance based on a baseline component Z and a time-varying component ΔZ. For example, ΔZ is expected to be approximately 0.5% of Z. An impedance electrocardiogram (ICG) can be the first derivative of ΔZ. In FIG. 13A, A is atrial contraction, B is aortic valve opening, C is peak systolic flow, X is aortic valve closure, Y is pulmonary valve closure, O is mitral valve opening, and LVET is left ventricular ejection time.

[0118] Referring now to the example of FIG. 13B, FIG. 13B is a graph of pulse arrival time determination according to one embodiment. PAT is pulse transmission time, PEP is pre-ejection period, and PTT is pulse transit time. PAT includes the time from the electrical onset of systole to the onset of left ventricular ejection (PEP). Impedance cardiography (ICG) is important because it can estimate blood pressure using the propagation characteristics of arteries. ICG can be used to measure blood pressure from the aortic valve opening to the arrival of the pressure pulse in the distal vessels. PEP can change with blood pressure, especially with short-term exercise.

[0119] Examples related to cutaneous bonding FIG. 14A illustrates a cross-sectional view of an embodiment 1440 of an optically clear adhesive under a photodiode and an LED, according to some embodiments. FIG. 14B illustrates a top view 1450 of the optically clear adhesive under a photodiode and an LED, according to some embodiments. The adhesive assembly can be used to adhere a physiological monitoring device to a patient. The embodiment 1440 can include a photodiode 1404, an LED 1402, a flexible circuit 1406 (such as a polyimide flexible circuit), brightness enhancement films 1408A, 1408B, and 1408C (collectively referred to herein as brightness enhancement films 1408), and an optically clear adhesive layer 1410. The optically clear adhesive layer 1410 can engage and adhere to a user's skin. Because the adhesive layer 1410 is optically clear, the optically clear adhesive layer 1410 can be directly bonded to the LED 1402 and the photodiode 1404. Advantageously, the LED and photodiode can bond very well to the user's skin. In some embodiments, the brightness enhancing film 1408 may be disposed within the flexible circuit 1406, overlay part or all of the flexible circuit 1406, extend beyond the flexible circuit 1406, and / or be disposed in other locations such as the like. The brightness enhancing film 1408 may be disposed over the flexible circuit 1406 and integrated with an adhesive that presses the flexible circuit 1406 and brightness enhancing film 1408 against the patient's skin. The brightness enhancing film 1408 and / or the optically clear adhesive layer 1410 may comprise any type of brightness enhancing film and / or adhesive that is biocompatible and skin-friendly. Furthermore, the brightness enhancing film 1408 and / or the optically clear adhesive layer 1410 may comprise any type of brightness enhancing film and / or adhesive that does not interfere with or enhances optical signal transmission.Some non-limiting examples of films or adhesives that may be used with certain embodiments described herein include Vikuiti™ Brightness Enhancing Film (BEF) III, Vikuiti™ Enhanced Specular Reflector (ESR), and Contrast Enhancement Film (CEF) 19XX series optically clear adhesives from 3M™.

[0120] In some examples, the embodiment 1440 includes a brightness enhancement film 1408 that can refract and / or reflect light to increase light output. Thus, light that would otherwise be absorbed by the device and not penetrate the skin can reflect off the brightness enhancement film 1408 and penetrate the skin. Additionally, light that does not reflect off the skin and toward the photodiode can get another chance by reflecting off the brightness enhancement film 1408, interacting with the skin, and reflecting back toward the photodiode. Advantageously, light that might not otherwise be absorbed by an opaque barrier can get another chance to reflect toward the skin or photodiode. The brightness enhancement film 1408 can be positioned between optical components, between the optical components and the skin, under an opaque layer of a flexible substrate, and / or in any location where light can be reflected. The embodiments described herein include a brightness enhancement film 1408. However, it is understood that other reflectors or materials that recycle light photons can be used. For example, the brightness enhancing film 1408 may be integrated with, adjacent to, and / or replace an optically clear adhesive and / or an enhanced specular reflector.

[0121] In some embodiments, the brightness enhancing film 1408 is flush with the photodiode and / or LEDs. In other embodiments, the brightness enhancing film 1408 is elevated toward the circuitry 1406 so that the open space between the photodiode and LEDs provides space for tenting the skin.

[0122] In some examples, the adhesive can surround one or more optical components, such as an LED or a photodiode. The adhesive can be applied between the optical components, such as between an LED and a photodiode. The adhesive can include an optically clear adhesive. The optically clear adhesive can be applied over one or more of the optical components, such as all of the LEDs or photodiodes.

[0123] In some embodiments, one or more moisture-wicking materials can be integrated into the adhesive, added onto the adhesive, placed near the adhesive, or substituted for the adhesive. Moisture-wicking materials can include polyester-type materials that can aid in the absorption and / or evaporation of substances such as goop or sweat. Moisture-wicking materials can be placed around the optic or interwoven with the adhesive.

[0124] In some instances, hydrophilic materials can be placed around the optics to attract fluid and repel fluid away from the optics, and hydrophobic materials can be placed (such as between the LED and PD) to repel fluid away from the optics.

[0125] In some examples, a light emitting component can be used to emit light and a light detecting component can be used to detect light. For example, the light emitting component can include an LED or an electroluminescent panel. The light detecting component can include a photodiode.

[0126] In some instances, the LED and photodiode are separate from the portion holding the electrodes. For example, the LED and photodiode may be held down to the patient's skin with a different adhesive than the adhesive holding down the electrodes. Figure 6 shows how the optical components 1202A, 1202B and the ECG sensor 1208 are positioned on different parts of the body with the same adhesive, but on different portions of the same adhesive.

[0127] In some embodiments, the optical components can be held down by a different portion of the same adhesive or by a different adhesive than for the ECG sensor. Advantageously, the optical components can have better bonding on the skin because the adhesive holds the components of a smaller size (e.g., only the optical components instead of a larger rigid housing that holds the optical components and electrodes).

[0128] In some examples, the optical sensor is on the same flexible wing as the electrodes. Advantageously, the device requires a smaller footprint than a device with separate flexible wings. In some examples, the optical sensor is on a separate flexible wing from the electrodes. Advantageously, having separate flexible wings can improve signal quality by reducing crosstalk between the ECG and PPG signals. Furthermore, having separate flexible wings provides the option of placing the PPG sensor in a better location on the chest (e.g., in a location with more blood vessels) than the optimal location of the ECG sensor.

[0129] In some examples, at least a portion of the traces for the electrodes run parallel to at least a portion of the traces for the light sensor. Advantageously, an electronic device (e.g., a device including flexible wings) can have a smaller footprint by reducing the amount of area that the traces use on the flexible wings, resulting in a much smaller footprint on the flexible wings. For example, the parallel-running trace portions originate from a housing that holds the electrical circuitry and battery.

[0130] In some examples, the electronic device includes a first electrode, a second electrode, a first adhesive, and a second adhesive. The first adhesive is configured to hold the first electrode on the patient's skin. The second adhesive is configured to hold the second electrode and one or more optical sensors on the patient's skin. The first and second adhesives are physically separated to prevent conduction between the two electrodes from creating a short circuit. The first adhesive can hold the first flexible wing on the patient's skin, and the second adhesive can hold the second flexible wing on the patient's skin. In some embodiments, the electronic device can include three adhesives. The first adhesive can hold the first electrode on the skin, the second adhesive can hold the second electrode on the skin, and the third adhesive can hold one or more optical components on the skin. In some embodiments, more adhesives can be used, such as a fourth adhesive for holding other optical components on the skin. In some embodiments, a single adhesive can hold multiple components, such as multiple electrodes.

[0131] In some examples, the electronics are configured to allow the optical sensor to be attached and detached from the device. The optical sensor is disposable and replaceable. The device can be used and modified to operate with only the electrodes, only the optical sensor, or both. For example, the optical sensor and traces can be connected to the electronics by attaching the ends of the traces to connectors on the housing. A detachable optical sensor can include its own adhesive separate from the adhesive for the electrodes.

[0132] FIG. 15A illustrates an embodiment 1500 for indenting a patient's skin according to some embodiments. In embodiment 1500, a wearable device can include one or more LEDs 1504A, 1504B (collectively referred to herein as LEDs 1504) and a photodiode 1502. The LEDs 1504 can indent a user's skin 1506. In embodiment 1500, two LEDs 1504A, 1504B can indent the skin at different locations on the skin. The skin can be tented, such as maintaining a triangular or tented appearance when sandwiched by the LEDs 1504. The LEDs 1504 can emit light into the tented region, and the photodiode 1502 can collect the light emitted from the tented region. The tented region can include a region of well-vascularized tissue. Advantageously, transmitting a signal through the tented region can improve signal quality by completely passing through the region of well-vascularized tissue.

[0133] While certain components are illustrated as being LEDs, electrodes, or photodiodes, it is understood that for FIG. 15A and other figures herein, these components can be switched, inverted, swapped, and / or replaced with other components (e.g., switching an LED for a photodiode and / or vice versa).

[0134] 15A shows a wearable device configured such that the wearable device extends beyond the LED 1504 away from a region configured to form a depression on the skin, such that this extended region is flush with the patient's skin. Thus, the wearable device can include a flush and / or flat surface with a depression in which the detector 1502 resides.

[0135] 15B shows an example 1520 of using two extensions of a wearable device to indent a patient's skin. Example 1520 of FIG. 15B shows a wearable device that does not extend beyond the LED 1504 away from an area configured to form an indentation on the skin so that the wearable device is flush with the patient's skin, but instead recesses from the peak where the LED 1504 is located. The wearable device can include a protrusion where the LED 1504 is located and a depression where the LED 1504 is not located (e.g., where the photodiode is located or at the end of the LED away from the central tent-shaped area).

[0136] In some examples, the wearable device can include multiple LEDs, such as LEDs 1504A and 1504B. Advantageously, more light can be shone onto the tent area for the photodetector to detect. More light can interact with the blood, and therefore more information related to the blood can be received by the photodiode. In other examples, a single LED 1504A can be used. The wearable device can indent the skin on one side via a single LED instead of two sides.

[0137] In some embodiments, the LEDs 1504 can be configured to emit light directionally toward the tented region of the skin. In some embodiments, the LEDs can be directional LEDs that emit light in a particular direction. Advantageously, the LEDs can focus light in a particular direction, minimizing or eliminating light that would otherwise be emitted away from the tented region.

[0138] In other examples, the LED 1504 can emit light in multiple directions, and additional materials can be used to block or redirect the light. For example, an opaque layer can block light emitting in the direction away from the tented region, or a reflective layer can be used to reflect light emitting in the direction away from the tented region, giving it another opportunity to emit toward the tented region of the skin. Additionally, the opaque layer can block external ambient light noise that could affect the LED and / or photodiode.

[0139] In some cases, unidirectional films or materials can be applied that emit light in one direction. For example, this material can be placed on, adjacent to, or near an LED or photodiode. Light emitted from the LED is emitted toward the material, which allows the light to pass through but blocks light coming from the other side of the material. Similarly, for a photodiode, light coming from the body can pass through the photodiode but light coming from the other side of the material can be blocked.

[0140] FIG. 15C illustrates an example 1540 of applying a fiber optic cable to project light onto a user's skin or into a skin depression, according to some embodiments. In some embodiments, the fiber optic cable or light guide can focus light toward the user's skin. The example 1540 can include a backing layer 1510, such as a polyimide backing layer, which can include a flexible or regular PCB substrate. The LEDs 1504 can each be coupled to light pipes 1508A, 1508B (collectively referred to herein as light pipes 1508) to direct light to the sides of the protrusions that form the skin depressions. The LEDs 1504 can be disposed on the backing layer 1510. Advantageously, manufacturing is improved by allowing the LEDs to be disposed on a flat substrate while still allowing light to penetrate into the tented portion, which is elevated from the backing layer.

[0141] In some embodiments, the light pipe may be made of or coated with a material having a particular refractive index, such as an optimal index match between two of the LED, air, skin, lens, and / or the like. For example, a favorable index match can be used for light passing from the LED to the user's skin relative to light transmitted to the skin. The light pipe can allow for a high percentage of light transmission. In some examples, the light pipe can be small in diameter to allow for better flexibility.

[0142] In some examples, the light pipe 1508 can include one or more opaque layers in portions of the light pipe. The opaque layers can prevent light from emitting in certain portions of the light pipe 1508. Portions that emit light into tented areas of the skin can be free of opaque layers. In some examples, the opaque layers can be positioned adjacent to, adjacent to, or between optical components.

[0143] In some examples, a cup or dome made of or covered with an opaque layer can be placed over one or more optical components. In some examples, the opaque layer can be in the form of a washer, donut, hollow-centered cylinder, and / or the like that surrounds the optical sensor. Advantageously, the opaque layer can prevent ambient light and crosstalk from introducing noise into the electrical signal.

[0144] In some embodiments, the backing layer can include a flexible PCB board. The flexible PCB board can be warped with protrusions and / or recesses to form depressions on the skin and / or tented areas of the skin. Advantageously, the LEDs and / or photodiodes can be fabricated to be disposed on the backing layer and positioned closer to the tented areas.

[0145] In some embodiments, the flexible substrate can bend during use to conform to the curvature of a user's skin. Flexible substrates can be thinner than other substrates. Such flexibility can allow for better coupling with the patient's skin.

[0146] In some instances, the LEDs and / or photodiodes are placed on a rigid substrate. Advantageously, this makes the components more stable, as the distance between the optical components is less susceptible to variations. Additionally, a rigid substrate can improve skin indentation.

[0147] 15A, 15B, and 15C are cross-sectional views of an electronic device. In some examples, the LED and / or photodiode can be rectangular. In other examples, the LED and / or photodiode can be circular. For example, the photodiode 1502 can be a sphere, a cylinder, an ellipsoid, and / or the like.

[0148] In some examples, LEDs 1504A, 1504B can be part of a single donut- or ring-shaped LED. The LED shape can consist of a single donut- or ring-shaped LED and / or can consist of multiple LEDs forming a donut or ring shape. In some examples, the LEDs or photodiodes can be incomplete donut- or ring-shaped, where only a percentage or portion of the LED is donut- or ring-shaped. For example, the LEDs can be in a 120-degree, 180-degree, 220-degree, 260-degree, or 300-degree ring shape, with the remaining area not containing any LEDs. Advantageously, this incomplete portion can mitigate some of the pinching that can occur when the LED digs into the skin.

[0149] 16 illustrates a top view of an embodiment 1600 for redirecting, minimizing, or removing sweat or other goop (e.g., dirt, oil, bacteria, or other bodily secretions or spills) from electronic components, according to some embodiments. The embodiment 1600 can include a photodiode 1602, LEDs 1604A, 1604B, 1604C, 1604D, and a channel 1606. The channel 1606 can allow sweat to escape and / or evaporate. The channel 1606 can include a trough, depression, tented area, or microfluidic channel for evaporating and / or evaporating sweat or goop that collects under an optical sensor.

[0150] In some examples, the channel 1606 can be positioned between the LED and the photodiode. The channel 1606 can be positioned in the same plane as the LED and photodiode. In some embodiments, the LED, photodiode, and / or other components can have a coating with a divot immediately adjacent to the component to allow sweat or goop to escape. In some examples, the adhesive that secures the electronic device to the skin can include divots or channels to allow sweat or goop to escape. In some examples, a backing layer, such as a flexible PCB, can include channels fabricated therein to allow sweat or goop to escape. In some examples, the backing layer can be a moisture-wicking and / or breathable material that helps promote sweat evaporation.

[0151] 17 illustrates an embodiment 1700 having a contact portion that applies pressure to an LED and / or photodiode for better bonding with the skin, according to some embodiments. Embodiment 1700 can include a contact portion 1704, which can include a recessed portion and a protruding portion, such as protruding portion 1705, a backing layer 1706, and an LED or photodiode 1702. Protruding portion 1705 can contact the LED or photodiode 1702 at a contact point. In some embodiments, the contact portion can include an opaque barrier material. Advantageously, the contact can serve the dual purpose of applying pressure and blocking light from penetrating the contact.

[0152] In some examples, the device is configured so that the user presses down on the housing and / or other portions of the device while the device is collecting measurements. For example, the user can initiate determination of the physiological characteristic, and / or the device can indicate to the user (e.g., via an LED or sound, or a message on the application) that the device is about to begin determining the physiological characteristic, or suggest to the user that it is about to begin, and the user is then to press down on the device to allow the sensors to obtain better coupling with the skin for measurement of ECG and / or PPG signals.

[0153] In some examples, the contact point can be a single point or area on the LED or photodiode 1702. Advantageously, the force that the contact 1704 applies to the LED or photodiode 1702 can be greater than if the backing layer 1706 were to press directly against the LED or photodiode 1702. The force of the contact 1704 applies more targeted pressure to the contact than if the backing layer were to press against the LED or photodiode 1702, because the backing layer applies pressure to the contact, which is transferred to the optical sensor at the contact. The backing layer 1706 can include a semi-rigid backing layer that applies downward pressure on the electronics indirectly toward the skin 1708.

[0154] In some examples, the electronic device can include a moisture-absorbing material near the contacts where the contacts press against the LED or photodiode. Advantageously, the moisture-absorbing material can prevent sweat from forming or accumulating at the contacts.

[0155] FIG. 18A illustrates an embodiment 1800 that uses a physical barrier to prevent adhesive or goop from flooding electronics, according to some embodiments. The embodiment 1800 can include a backing layer 1802, an optical component 1804 (such as a photodiode), adhesives 1806A and 1806B (collectively referred to herein as adhesive 1806), and physical barriers 1808A and 1808B (collectively referred to herein as physical barrier 1808). With extended use of the wearable device, the adhesive 1806 can begin to leak from underneath and onto other electronic components, such as the optical component 1804. Such goop (e.g., adhesive or a mixture of adhesive and sweat or other bodily exudates or spills) can leak underneath the LED or photodiode and block the optical signal from being emitted or detected. The physical barrier 1808 can block the adhesive from flooding onto electrical components, such as the LED or photodiode. The physical barrier can isolate the sensor from the adhesive or goop. In some instances, adhesives can be used that have properties that prevent or mitigate the formation of goop.

[0156] In some embodiments, the physical barrier 1808 is sloped toward the adhesive to further reduce the potential amount of adhesive leakage toward the electronic components. The physical barrier 1808 also prevents the adhesive from contacting electronic components, such as LEDs or photodiodes, even before the adhesive is applied to a user. The physical barrier 1808 can include a rigid structure next to the adhesive. The physical barrier 1808 can include a thin film adjacent to the adhesive. The physical barrier 1808 can include a non-adhesive surface.

[0157] 18B shows an example 1850 of a single LED and / or multiple LEDs in the shape of a donut or ring, according to some embodiments. The example 1850 can include a donut- or ring-shaped LED 1852. The donut- or ring-shaped LED 1852 can emit light toward the center of the donut or ring, toward a detector 1854. In some examples, the LED can illuminate a donut- or ring-shaped light pipe. The light pipe can emit light toward a photodiode.

[0158] 19 illustrates an embodiment 1900 with LEDs that emit light of different wavelengths, according to some embodiments. The embodiment 1900 includes an LED 1902 that can emit light of one wavelength, such as green light, and another LED 1904 that can emit light of another wavelength, such as red light. The LEDs 1902, 1904 can emit light of different wavelengths in a tented region, and a photodiode 1906 can detect light from both LEDs.

[0159] In some examples, the detector can simultaneously detect light from both LEDs, which emit light at different wavelengths. In some examples, the LEDs can emit light along multiple wavelengths or along a spectrum focused around a particular wavelength. In such cases, the wearable device can be configured to filter light of a first wavelength emitted from the first LED to remove light of a second wavelength corresponding to light emitted from the second LED.

[0160] In some examples, such filtering can be achieved through signal processing, such as a frequency filter, or through a physical filter on the photodiode. For example, if green light is emitted from the left side and red light is emitted from the right side, a first photodiode can include a physical filter on the left side to allow the green light to pass, and a second photodiode (or the same first photodiode) can include a physical filter on the right side to allow the red light to pass.

[0161] In some examples, a first LED can emit light and a detector can detect light from the first LED at a first wavelength, and then a second LED can emit light and a detector can detect light from the second LED at a second wavelength.

[0162] 20 illustrates an example 2000 of an LED and photodiode repeater according to some embodiments. LEDs 2004A and 2004B can emit light to the left and right, and photodiodes 2002A, 2002B, and 2002C can detect the emitted light. LEDs 2004A and 2004B can emit light into a tent-shaped area between the LEDs. The LEDs can include bidirectional LEDs that emit light in two directions, such as a left tent-shaped area and a right tent-shaped area, or omnidirectional LEDs.

[0163] 21 illustrates an example 2100 of different adhesives for a wearable device, according to some examples. This example 2100 can include a photodiode 2104 and LEDs 2102A, 2102B with multiple adhesives, such as a first or inner adhesive 2106 close to the electronics, and a second or outer adhesive 2108 on the outside.

[0164] In some examples, the first and / or second adhesives can include openings or slits that allow flexibility with patient movement. If the slits are along a vertical axis, the adhesive may stretch more horizontally when user movement creates tension along a horizontal axis. The openings or slits can help reduce movement on the housing or components or isolate the sensor from user movement.

[0165] In some examples, different adhesives can have different levels of tackiness. For example, the first adhesive 2106 can be less tacky than the second adhesive 2108, or vice versa. The outer adhesive 2108 can be a thicker, load-bearing adhesive than the inner adhesive 2106. The thicker adhesive may flow better to the body, be moisturizing, and be warmer against the skin, but may have more adhesive goop than the inner adhesive 2106.

[0166] In some examples, the inner adhesive 2106 can be thinner, more optically clearer, less tacky, less goop-forming, harder, and / or the like than the outer adhesive 2108. In some examples, the wearable device can have only the outer adhesive 2108 without the inner adhesive 2106, or vice versa. Advantageously, electrical components can be protected from goop leaking from the adhesive.

[0167] Figure 22A illustrates an embodiment 2200 having a single LED and a single photodiode according to some embodiments. The single LED 2202 can emit light toward a single photodiode 2204. Figure 22B illustrates an embodiment 2220 having an array of LEDs and an array of photodiodes according to some embodiments. The array of LEDs 2202A, 2202B, 2202C, 2202D (collectively referred to herein as array of LEDs 2202) can emit light toward the array of photodiodes 2204A, 2204B, 2204C, 2204D (collectively referred to herein as array of photodiodes 2204).

[0168] FIG. 22C illustrates an example 2240 of LEDs and photodiodes distributed in a circular array according to some examples. LED 2202 can emit light toward the center of the circular array, and photodiode 2204 can detect light coming from the center of the circular array. The structure of example 2240 can be such that a tent-shaped area of ​​skin can be created within the circle for light to penetrate. The LEDs and photodiodes can be alternated around the periphery of the circular array. Advantageously, any photodiode can pick up light coming from all LEDs emitting toward the same tent-shaped area of ​​skin. The wearable device (or other computing device) can sum the signals collected from the photodiodes to generate a stronger signal strength. In some examples, the computing device can time align the received signals before summing the collected signals.

[0169] FIG. 23A shows an example 2300 of a protrusion lined with an illumination channel, according to some embodiments. Example 2300 includes an LED 2302, a photodiode 2304, and illumination channels 2306A, 2306B. The illumination channel or light pipe can capture light emitted from the LED and guide the light through illumination channel 2306A. Illumination channel 2306A can allow light to exit from the LED side to the photodiode side. Illumination channel 2306B on the photodiode side can capture light emitted from the LED side and deliver the light to photodiode 2304. In some embodiments, the LED and / or photodiode include and / or are integrated with the illumination channel. By guiding the light, a greater percentage of the emitted light can be directed through the skin from the LED 2302 to the photodiode 2304 or between the LED 2302 and the photodiode 2304.

[0170] 23B illustrates an embodiment 2350 using a ring or light pipe according to some embodiments. The embodiment 2350 includes multiple LEDs 2302A, 2302B, a photodiode 2304, and light pipes 2306A, 2306B. Each LED can have its own light pipe for directing light from the LED to the patient's skin (e.g., a tent of the skin). The photodiode 2304 can capture light emitted from multiple light pipes 2306A, 2306B, which may be collectively referred to as light pipes 2306.

[0171] FIG. 24 illustrates an example 2400 of a leaf spring pressing against certain components of a wearable device, according to some embodiments. The example 2400 includes a rigid portion 2406 that applies pressure to an LED 2402 and a photodiode 2404. The conformal portion of the wearable device may include flexible portions 2408A, 2408B, which may be non-adhesive, and adhesive layers on both sides 2410A, 2410B. The rigid portion may include a leaf spring for exerting a downward force toward the LED and photodiode. Advantageously, the rigid portion may exert a force on the LED and photodiode to improve coupling with the skin. Improving coupling with the skin may include increasing contact between the LED and / or photodiode and the skin. Furthermore, applying pressure or force to the LED and / or photodiode toward the skin may result in improved signal quality or may be adjusted to achieve better or optimal signal quality. It should be understood that the present disclosure is not limited to leaf springs and that other types of springs or mechanisms can be used to apply a downward force towards the LED and / or photodiode.

[0172] FIG. 25 illustrates an embodiment 2500 of a bowl-shaped flexible circuit that recesses into the skin, according to some embodiments. The embodiment 2500 can include LEDs 2502A, 2502B, a photodiode 2504, adhesive on sides 2508A, 2508B, and a backing substrate 2506. The backing substrate 2506 can be bowl-shaped or recessed to naturally apply pressure to the LEDs and photodiode for better bonding with the skin. In some cases, the backing substrate 2506 is affixed to the flexible circuit and applies pressure to the flexible circuit to improve bonding between the LEDs 2502A, 2502B and photodiode 1504 and the patient's skin. In some embodiments, the backing substrate 2506 can include protrusions that naturally apply pressure in one direction. While pressure can be applied in the opposite direction by skin or user movement, the protrusions can withstand a certain amount of pressure without losing their shape while continuing to apply pressure toward the skin.

[0173] 26A shows an example embodiment 2600 of an opaque barrier between an LED and a photodiode, according to some embodiments. Example 2600 can include LEDs 2602A, 2602B, a photodiode 2604, and opaque barriers 2606A, 2606B (collectively referred to as opaque barrier 2606). When light is emitted from LED 2602 into tented region 2608 of the skin, opaque barrier 2606 can block the light from passing directly from LED 2602 to photodiode 2604. In some embodiments, opaque barrier 2606 is positioned closer to the LED than the photodiode.

[0174] In some embodiments, the LED can include a lens to direct light toward a specific area, such as a tented region of the skin. For example, the lens can have a roughened surface that is not directed toward the tented region of the skin, while the surface that is directed toward the tented region of the skin can be transparent, thus allowing light from the LED to be emitted toward the tented region of the skin. The roughened surface can create a difficult propagation path for light emitted in undesired directions.

[0175] FIG. 26B illustrates an embodiment 2650 of pseudo-transmit from an LED directly through a tented region of skin to a photodiode, according to some embodiments. This embodiment includes an LED 2652 and a photodiode 2654 between tented regions of skin 2656. The skin is tented due to the pressure the LED and photodiode exert on the sides of the skin. The optical signal can be emitted from the LED 2652 and pass directly through the skin to reach the photodiode 2654, resulting in improved signal strength over conventional reflected signals. Additionally, the LED and photodiode can be placed on elevated structures 2658A, 2658B, such as rails, and pressed further into the skin to form a larger tented region.

[0176] Figure 27A shows a cross-sectional view 2700 of an embodiment using fiber optic bundles for LEDs and photodiodes, according to some embodiments. Figure 27B shows a side view 2750 of an embodiment using fiber optic bundles, according to some embodiments. A first bundle 2702 of fiber optics can be attached to one or more LEDs, and a second bundle 2704 of fiber optics can be attached to one or more photodiodes.

[0177] In some embodiments, light emitted from the LED passes through a first bundle of optical fibers 2702 and shines onto the user's skin 2706. The light may be reflected from the skin and received by a second fiber optic bundle 2704 and transmitted to a photodiode. The electronic device is pressed into the skin of the user 2706, creating an indentation in the skin. In some embodiments, the optical fiber presses slightly into the skin. In other examples, the optical fiber is adhered to a flat surface, with the flat surface against the skin. In some examples, the optical fibers are spaced a distance apart, such as a centimeter, a half centimeter, a quarter centimeter, and / or the like.

[0178] In some examples, the LED and photodetector can share the same fiber optic channel. For example, fiber optic bundles can be woven into the same fiber optic channel, with a single bundle in the channel separating at one end to connect to the LED and photodetector and at the other end to the skin-contacting layer 2708. In some examples, the fiber optic channel can have an inner core for the LED and an outer core for the photodetector.

[0179] In some instances, the same channel is used for the LED and the photodetector: for example, when the LED is emitting light, the fiber optic channel is used for the LED, and when the photodetector is detecting light, a switch switches the fiber optic channel to the photodetector.

[0180] In some examples, the electronic device includes an accelerometer to account for movement. For example, if large movements are detected, the electronic device can discard measurements. The electronic device can also filter out noise resulting from movement, such as when the movement is at a specific frequency.

[0181] In some instances, a specific input impulse signal or signal signature can be transmitted to an LED. A photodetector detects the emitted light, and a processor looks for the specific input impulse signal or signal signature input to the LED. Applying a filter, such as a match filter, can significantly improve the signal-to-noise ratio of the received signal.

[0182] In some examples, the ECG sensor and the PPG sensor are placed at different locations, such as one on the chest and one on a finger or toe. The received ECG and PPG sensor data can be received by the same circuitry, which can facilitate time synchronization. This circuitry can estimate a time delay to provide information about blood pressure, as disclosed further herein. The signal travels fast enough so that the time delay is no greater than the length of a pulse.

[0183] Examples of cutaneous bonding FIG. 28A illustrates an example of skin coupling via two doming compounds according to some embodiments. For example, the skin coupling may be between device 1200 and a patient's chest. Additionally, the skin coupling may be between a flexible wing (e.g., wing 330 or wing 331) of a device (e.g., device 300) and a patient's chest. Skin coupling example 2800 may include an LED 2802, a detector 2804, two doming compounds 2806A, 2806B (collectively referred to herein as doming compounds 2806), and / or an opaque barrier 2812. Dominating compound 2806 may be hemispherical in shape. Dominating compound 2806 may extend from LED 2802 and detector 2804 into a patient's skin surface 2810. Dominating compound 2806 may include a glass lens-like compound for transmitting an optical signal. The doming compound 2806A can be shaped like a dome or convex lens to direct light from the LED 2802 towards the skin, and / or the doming compound 2806B can be shaped like a dome to direct light from the skin back towards the detector 2804.

[0184] In some embodiments, skin-coupling embodiment 2800 includes an opaque barrier 2812. One possible drawback of having LED 2802 and detector 2804 in close proximity is the potential for optical signal crosstalk, where at least a portion of the optical signal travels directly from LED 2802 to detector 2804 without passing through the skin. In a crosstalk signal, detector 2804 does not detect a signal containing physiological information. Opaque barrier 2812 may be included to block signals from traveling directly from LED 2802 to detector 2804.

[0185] While the skin-coupling example 2800 includes an opaque barrier 2812, it is understood that other barriers that block the optical signal can be used. For example, one or more barriers that absorb stray light and / or reflect these rays can be applied to limit light from traveling directly from the LED to the photodetector. The one or more barriers can be configured to divert and / or direct oblique light rays to the photodetector. In some examples, the opaque barrier 2812 can extend beyond the LED 2802 and / or detector 2804. In other examples, the opaque barrier 2812 can extend partially beyond the edge of the detector 2804 and / or beyond the LED 2802 closest to the opaque barrier. For example, the dome can include a circular and / or rounded portion that curves inward away from the opaque layer, and the opaque layer can fill gaps that would otherwise not be filled by a rectangular-shaped opaque barrier. In some examples, the opaque barrier 2812 can be of various thicknesses and / or heights. In some examples, the opaque barrier 2812 can be at a height that is lower than the top of the dome so that the opaque barrier rises to different points on the dome.

[0186] In some embodiments, the device can block unwanted signals or frequencies via a doming compound that has specific light-refractive or light-beamforming properties that can redirect or redirect light away from other optical components without a physical barrier corresponding to the specific frequency.

[0187] In some embodiments, the device can block unwanted signals using a specific material, such as silicone doped with a black dye to form a physical barrier. This material can include a type of biocompatible epoxy (e.g., flexible after curing) that is opaque or can be made opaque via dye or other processes.

[0188] In some embodiments, the device can block unwanted signals based on the thickness of the opaque barrier's material in the z-direction. The opaque barrier can be at least as high as the LED and PD, but can also extend beyond the LED and / or PD. If a doming compound is present, the opaque barrier can be at the height of the dome (as in the embodiment shown in FIG. 28A) or along the dome. The opaque barrier does not need to span / bridge the space between the LED and PD. The dome can include a wire (e.g., an electrically insulating material) running between the LED and PD.

[0189] In some examples, the skin-bonded example can include a reflective layer. For example, the reflective layer can be next to the opaque layer. The portion of the opaque barrier 2812 that can contact the skin can have a reflective layer therebetween.

[0190] Advantageously, light transmitted from doming compound 2806A can be reflected from the reflective barrier instead of being absorbed by the opaque barrier 2812. Reflecting light from the reflective barrier can improve signal quality as the light travels from doming compound 2806A to doming compound 2806B.

[0191] FIG. 28B illustrates another example of skin coupling via two doming compounds, according to some embodiments. In the skin coupling example 2820, the two doming compounds 2806 can be positioned lower so that the doming compounds are pressed further into the skin surface. In some embodiments, the two doming compounds 2806 can have a greater length so that the doming compounds are pressed further into the skin surface. In the skin coupling example 2800, the doming compound 2806 can include a curved surface, such as a dome shape. The amount of depression the doming compound presses into the skin surface can depend on various factors. For example, the amount of depression can depend on whether the depression can block small blood vessels close to the surface, preventing these signals from being processed. The amount of depression can depend, at least in part, on the amount of light and associated hemodynamic information that can be transmitted from the LED to the detector via interaction with the blood vessels, which can lead to larger and / or more accurate signals.

[0192] In some examples, the curved surface can be curved a number of degrees, such as 180 degrees. At least a portion of the curved surface can be configured to contact the patient's skin surface 2810. For example, in the skin-coupling example 2800, a portion of the curved surface contacts the skin surface 2810 and another portion of the curved surface contacts the opaque barrier 2812. Advantageously, sweat can be trapped between the doming compound and the opaque barrier and / or opposite side of the doming compound. Other substances, such as sweat, help couple light into and out of the skin.

[0193] In another example, skin coupling example 2820 includes a curved surface, the entire curved surface being configured to contact the patient's skin surface. One side of the cylindrical portion of doming compound 2806 contacts opaque barrier 2812. In this example, the cylindrical portion of doming compound 2806 is flush with opaque barrier 2812. Advantageously, other substances, such as a user's sweat, can be prevented from being trapped between doming compound 2806 and opaque barrier 2812 when this is undesirable, such as for cleanliness reasons (e.g., for a device that is left on a patient for days) or when the substance disperses the signal instead of focusing the light on the skin. Other substances, such as sweat and dirt, can also affect index matching. For example, a mismatch in the refractive index between two materials can result in light being deflected as it enters and / or exits the material. The refractive index of a material can be desirable or undesirable based on the direction of light from the LED to the skin or from the skin to the detector. Generally, a material like sweat with a refractive index close to that of skin helps match the interface and suppress back-reflection from the skin surface that would result from a large mismatch.

[0194] In the skin-coupled example 2820, the doming compound 2806 can be pressed more deeply into the skin than in the skin-coupled example 2800. Advantageously, the skin-coupled example 2820 can direct more of the transmission-mode PPG-type signal from the curved surface of the doming compound 2806A for the LED 2802 directly to the skin surface and through to the doming compound 2806B for the detector 2804. In contrast, the skin-coupled example 2800 can capture more of the reflection-mode PPG-type signal bouncing off tissue components within the patient's body, such as blood vessels. In the skin-coupled example 2820, the transmission-mode PPG signal can be used to capture more of the signal from superficial blood vessels. However, the reflection-mode and / or transmission-mode PPG signal can be used to detect more of the deeper blood vessels. In some examples, both the transmission and reflection signals can be present and used to generate a more accurate optical signal and / or one that provides more information about the different layers of skin tissue.

[0195] In some examples, the skin-bonding example can include an optically transparent film or adhesive that can include wavelength-guiding properties to help redirect light to travel more efficiently from the LED to the detector. Wave-guiding properties can include a polarized lens that allows more light to pass in a specific direction, such as from the LED toward the skin surface toward the detector. Advantageously, less light is lost in the opposite direction of the LED, away from the detector. In some examples, other directional light-emitting technologies can be used, such as phased array optics that control the phase and amplitude of light waves transmitted, reflected, or captured by the surface. Such phase and / or amplitude adjustments can be applied to direct the light beam in a specific direction without moving parts. Advantageously, the light beam can be steered in a direction away from the LED to enhance stronger signal detection at the detector. Furthermore, on the receiving side, the detector can include a phased array photodetector that can extract a stronger signal from the LED.

[0196] FIG. 28C shows example circuits 2840 and 2860 according to some embodiments. The circuits 2840 and 2860 can include two photodiodes 2842 and 2844. In some embodiments, the system can include multiple LEDs or receivers. The circuits include two receivers and one emitter. The system can subtract or reduce noise from the circuits by rejecting common baseline information present on both receivers, which can include electrical noise such as 60 Hz noise. In some examples, one photodiode can act as a reference signal for the amount of optical power delivered to the skin, while the other photodiode acts as the receiver diode. If the bandwidth of the power reference photodiode op-amp circuit is the same as the bandwidth of the receiver photodiode, a technique called autobalance detection can cancel power fluctuations in the LED output down to approximately one-third of the bandwidth by comparing the reference photodiode signal to the receiver photodiode. Autobalance detection is very effective at canceling common-mode noise to very high orders, for example, when the LED output is fluctuating in a way that affects the extraction of the detector signal. The system also captures hemodynamic information from light interacting with blood vessels on either side of a single emitter by adding together the AC components of the signals from both receivers and increasing the area of ​​skin sampled. By varying the receiver and emitter geometry, different regions of the skin can be sampled. Placing the two receivers at different distances from the emitter also allows the signal to interact with different tissue depths, providing information about both superficial and deep vessels. The two receivers can also include different wavelength filters to obtain more complex information about how different wavelengths of light interact with vascular tissue.

[0197] FIG. 28D illustrates an example of skin coupling using an inward-facing meniscus or concave glass lens, according to some embodiments. Skin coupling example 2880 can include an LED 2802, a detector 2804, an opaque barrier 2812, and inward-facing meniscus glass lenses 2882, 2884. Detector 2804 can be a photodiode or other type of photodetector. The inward-facing meniscus glass lenses 2882, 2884 can intentionally trap other substances, such as saline or sweat, that index-match the stratum corneum, the top layer of skin. Advantageously, the meniscus design can allow sufficient moisture on the skin to improve light incidence on the skin. Additionally, the concave lens can tent the skin toward the LED 2802 and detector 2804 (e.g., photodiode) when the device (e.g., device 1200 or device 300) is applied to a user's skin (e.g., chest).

[0198] FIG. 29A illustrates the use of a high index material as a skin-bonding example 2900, according to some embodiments. For example, the material can have a refractive index greater than 1.5, greater than 1.6, between 1.55 and 1.75, greater than 1.75, greater than 1.8, etc. The high index material 2902 can include a meniscus shape and be index-matched to the stratum corneum. For example, the high index material can be selected to have the same refractive index as the stratum corneum. The high index material 2902 can be positioned below the visual target 2904 and can be used, for example, to form a dome represented by a doming compound 2806 or meniscus or concave lenses 2882, 2884. The optical element 2904 can include an optical element such as an LED or photodiode. The high index material 2902 can include the inward-facing meniscus glass lenses 2882 or 2884 of FIG. 28D.

[0199] 29B illustrates a doming compound that laterally overlaps at least a portion of the opaque barrier 2934 and protrudes beyond the opaque barrier 2934, increasing the contact area with the skin, according to some embodiments. Skin-bonding example 2930 includes a doming compound 2932 that protrudes beyond where the opaque barrier begins. Advantageously, sweat is not trapped between the doming compound and the opaque barrier. Additionally, the shape of the doming compound may allow light to be emitted below the opaque barrier, interacting with the skin and increasing the amount of light that can be received by the detector.

[0200] 29C shows an example ball lens, according to some embodiments. In some examples, the example skin coupling 2960 can include a full circle, ball, or sphere 2962. The sphere 2962 can include a sapphire ball lens, which has the advantage of being index-matched to the skin. The adhesive 2964 used to attach the LED or detector to the sphere 2962 can be applied to at least a portion of the curved surface of the sphere 2962.

[0201] 30A shows a basic template of an LED and detector mounted on a flexible circuit from which a waveguide can be constructed on a surface according to some examples. This example 3000 can include an LED 3002, a detector 3004, and a flexible circuit 3006. The flexible circuit 3006 can include a surface portion that can be coupled to a patient's skin.

[0202] 30B shows an example of a waveguide flexible circuit 3620 according to some embodiments. A waveguide 3602A can be attached to the LED 3002 such that light emitted from the LED 3002 can flow throughout the waveguide 3602A. The detector 3004 can include a waveguide 3602B such that light can be captured through various regions of the waveguide 3602B and / or throughout the waveguide 3602B and received by the detector 3004. The waveguide can be made of an adhesive polymer that is adhered to a polyimide backing of the flex circuit that holds the LED and detector.

[0203] In some embodiments, the flexible circuit can include a 2D spread that tracks across a larger area of ​​the skin portion, such as across a larger portion of a user's chest. By using these waveguides, the system can include fewer LEDs and / or detectors, such as one LED and one detector in FIG. 30B, but can have multiple data sources, effectively having three detectors and two LED light sources (DET1-SOURCE1-DET2-SOURCE2-DET3). Furthermore, light shining from Light Source 1 to Detector 1 may have a larger signal than light shining from Light Source 1 to Detector 3, but may penetrate the skin more shallowly. Signals transmitted from various light sources along LED waveguide 3602A and / or signals received from various tracks along detector waveguide 3602B can be combined to create a stronger detection signal or analyzed by separation distance to obtain more detailed information related to tissue depth.

[0204] FIG. 30C illustrates an example of an adhesive used for a dome-shaped glass lens, according to some embodiments. Example 3040 includes adhesive 3042 bonding the LED / detector and the dome-shaped glass lens. FIG. 30D illustrates an example of an adhesive used for an inverted dome-shaped glass lens, according to some embodiments. Example 3060 includes adhesive 3062 bonding the LED / detector and the inverted dome-shaped glass lens. An inverted dome-shaped lens may have the advantage of a flat contact surface to limit skin blanching. The LED and / or detector are bonded to the glass lens via an adhesive. The adhesive can be an optically clear film, an optically clear adhesive, or an assembly including a high refractive index resin or epoxy. An opaque barrier can then be backfilled around the perimeter.

[0205] FIG. 31A shows an example of ray tracing of LED-emitted light, according to some examples. FIG. 31B shows an example of ray tracing of detected light, according to some embodiments. In both examples 3100 and 3120, light can be absorbed by opaque barriers 3104A, 3104B, bounced off a wall and guided, or injected directly. In example 3100, light can be emitted from LED 3102A onto glass lens 3106A. Light can penetrate the skin by being absorbed by opaque barrier 3104A and / or bounced off a surface and guided, and / or injected directly into the skin.

[0206] Light emitted from an LED, such as LED 3102A, and projected onto the skin through a glass lens, such as 3106A, can be scattered, reflected, and absorbed by the patient's body. The reflected light can be received by a detector. In embodiment 3120, the light can be received by glass lens 3106B, absorbed by opaque barrier 3104B, and / or guided by bouncing off the surface and received by detector 3102B, and / or directly incident on detector 3102B. Advantageously, when the LED and detector are positioned on the surface of the chest, the LED can transmit light through the patient's chest, and some of the light can be reflected after interacting with the many surface capillaries that supply and / or vascularize the superficial layers of the skin, allowing the detector to detect these signals. These signals can be used to determine blood pressure and other hemodynamic characteristics.

[0207] Figures 31C, 31D, 31E, 31F, and 31G show steps for creating different types of domes over LEDs and detectors, according to some embodiments. Figure 31C shows an example of a flexible substrate 3146, a circular pedestal 3144, and an LED / detector 3142, according to some embodiments. Figure 31D is a top view of Figure 31C, according to some embodiments. The circular pedestal 3144 can be placed on the flexible substrate 3146. The LED / detector 3142 can be placed on the circular pedestal 3144.

[0208] FIG. 31E illustrates an example of adding a Teflon tube 3145, or a tube of other material, according to some embodiments. The Teflon tube 3145 can absorb and / or reflect the signal coming into the detector and / or the signal emitted from the LED. FIG. 31F illustrates an example of adding or creating a lens 3148 that fits within the Teflon tube 3145 and over the LED / detector 3142, according to some embodiments. The lens 3148 can be created by filling a mold with a UV curable or other optically correct adhesive to form the desired meniscus. The lens 3148 can scatter and / or direct light from the LED or light to the detector 3142. Using this method, the lens 3148 can be made thicker or thinner, depending on, for example, the desired indentation on the patient's skin. FIG. 31G illustrates an opaque barrier 3150 added to the side of the Teflon tube 3145, according to some embodiments. The opaque barrier 3150 can prevent and / or mitigate crosstalk between the LED and the detector.

[0209] FIG. 32 shows a mold for creating an opaque barrier surrounding a sapphire half-ball glass lens, according to some embodiments. In this embodiment 3200, the flexible optical substrate 3202 can include a flexible polyimide substrate. A photodiode (e.g., detector 3206) can be soldered to the flexible optical substrate 3202, and an LED (e.g., LED 3208) can be soldered to the flexible optical substrate 3202. A sapphire half-ball glass lens 3212 can be bonded to the detector 3206 and the LED 3208. A blocker, such as an O-ring 3204, can be placed around the periphery of the flexible optical substrate 3202 to prevent the opaque barrier 3210 from simply flowing to the right when the material used to form the opaque barrier 3210 is injected or otherwise applied around the areas of the LED, detector, and half-ball lens. The amount of opaque barrier 3210 can be filled based on the amount of glass node exposure and / or contact with the patient's skin desired.

[0210] Figure 33A illustrates a clamp 3214 that can clamp an o-ring 3204, according to some embodiments. Figure 33B illustrates a top view of Figure 33A, according to some embodiments. Figure 33C shows a side view and a cross-sectional view of the o-ring 3204, according to some embodiments.

[0211] Figures 34A, 34B, and 34C show example skin-coupling prototypes, according to some embodiments. Example 3400 is an example of a flexible optical substrate that can include a flexible printed circuit (FPC) cable 3402, an LED 3404, and a detector 3406. Figures 34B and 34C show examples of different amounts of applied light barrier, according to some embodiments. Example 3420 in Figure 34B shows an example in which a smaller amount of light barrier is applied than example 3440 in Figure 34C because the light barrier in Figure 34B is thinner, exposing more of the LED and detector.

[0212] Figures 34D and 34E illustrate the operation of a skin coupler according to some embodiments. Figure 34D shows light emitted from an LED, and Figure 34E shows a user's finger over the LED. A detector is on the same side as the LED and detects the signal emitted from the LED, passing through the body, and reflecting back to the detector.

[0213] FIG. 34F shows another example of skin coupling where a flexible optical substrate can be placed directly on the chest surface and an adhesive 3462 can be used to hold a housing 3464 containing the optical components to the patient's skin.

[0214] 35A and 35B illustrate examples of skin coupling using a conformal coating, according to some embodiments. FIG. 35A illustrates the use of a conformal coating of one thickness, and FIG. 35B illustrates the use of a conformal coating of another thickness. However, it is understood that other thicknesses, such as 10, 20, 50, 100, 200, 500, and 1000 μm, can be applied. Because the LEDs and photodiodes protrude from the flexible optical layer, applying a conformal coating to the LEDs and photodiodes can provide electrical insulation between the optical components and the skin and mechanical protection to soften the sharp edges of the optical components. With a thin coating, the LEDs and photodiodes may scratch the patient's skin, such as the skin on the patient's chest.

[0215] Conformal coatings can include optically transparent materials, electrically insulating materials, and / or biocompatible high-finish epoxies. Advantageously, conformal coating approaches enable the use of thinner materials, enabling thinner form factors. Advantageously, thinner form factors can enable better bonding of the optical components to the skin, for example, by seamlessly integrating them with an adhesive assembly. Thinner form factors also require less force to apply the appropriate pressure to the optical components to achieve sufficient bonding to the skin. Furthermore, thinner conformal coatings, in the micrometer thickness range (e.g., 100–200 micrometers thick), significantly reduce crosstalk between the LED and the detector. In contrast to using a large glass lens, a conformal coating does not direct light from the LED to the detector (or significantly reduces the amount of light that is directed). Given the wavelength and lateral propagation of light, a thin layer of conformal coating can prevent (or significantly reduce) crosstalk between the LED and the detector, provided the conformal coating is sufficiently thin. Because the conformal coating is thin, more light can ultimately penetrate the skin, rather than reflecting and then reflecting again to reach the detector directly without physiological contact. In contrast, if the conformal coating is thicker, there is a higher probability that the light will bounce back and travel to the other side of the conformal coating (e.g., right next to the detector).

[0216] FIG. 36A illustrates an example embodiment 3600 of a method by which light can be emitted from an emitter 3602 to a patient's skin, according to some embodiments. FIGS. 36B and 36D illustrate examples of a light emitting diode (LED) 3602, a detector 3604, and an epoxy bridge 3606A therebetween, according to some embodiments. The bridge 3606A in these examples is thicker than the bridge 3606B shown in FIGS. 36C and 36E. The bridge 3606B in FIGS. 36C and 36E illustrates an example in which much of the epoxy in the bridge between the LED 3602 and the detector 3604 has been removed, further reducing the possibility of crosstalk between the LED 3602 and the detector 3604.

[0217] Advantageously, all components are conformally coated to protect the patient by providing a conformal coating on exposed solder and exposed electrical contact pads. Additionally, the epoxy is biocompatible and is a single surface layer, as opposed to multiple layers (such as with an opaque barrier and glass lens). Furthermore, the LED shines light directly onto the skin through a thin lens, allowing for a more concentrated light output than would be possible with a thicker or domed glass lens, which would scatter the light across the skin, reducing the amount of light that could interact with the target tissue and reflect back to the detector.

[0218] In some examples, biocompatible substrates, LEDs, and / or detectors may be used so that the conformal coating does not need to cover the entire surface of the LED, photodiode, and / or substrate, or a thinner coating is required.

[0219] In some instances, conformal coatings can help to uniform the thickness of the device around the LED and photodiode. For example, the LED and photodiode may vary in thickness, and a conformal coating can be applied to bring the LED and photodiode closer together than they would be without the conformal coating. Advantageously, when the device is worn on a patient's body, a smaller thickness variation can avoid or mitigate air gaps that form between the LED / detector and the patient's skin.

[0220] Figures 37A and 37C show a first example of skin coupling, and Figures 37B and 37D show a second example of skin coupling. Figures 37A and 37C can have different components, such as different LEDs or photodiodes, than Figures 37B and 37D. The spacing between the photodiode and LED in Figures 37A and 37C is smaller than that in Figures 37B and 37D. For example, the spacing between the photodiode and LED can be 1 micrometer, 2 micrometers, 5 micrometers, 10 micrometers, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 100 micrometers, 200 micrometers, 500 micrometers, 1 millimeter, 1.5 millimeters, 2 millimeters, 2.5 millimeters, 5 millimeters, 10 millimeters, or spacing between the above distances. The spacing can be from the center of the LED to the edge of the photodiode. The LED can be a red LED, a green LED, an infrared LED, and / or the like. The LED can emit light at a specific wavelength and / or at a variety of wavelengths. Photodiodes can measure light at a specific wavelength and / or at a range of wavelengths.

[0221] 38A-40B illustrate examples of adhesive assemblies that mate with a housing surrounding an electronic device, according to some embodiments. The adhesive assembly can include a portion of a wearable device that adheres to a patient's skin, for example, as shown and described with respect to FIGS. 14A and 14B and elsewhere herein. The adhesive assembly 3802 can include mating components such as 3804A, 3804B, 3804C, 3804D, 3804E, and 3804F (collectively referred to herein as mating components 3804). FIG. 38A illustrates a front view of an electronic component 3806 on the adhesive assembly 3802, and FIG. 38B illustrates a perspective view. FIG. 38C illustrates a perspective view of the electronic component 3806 mating with the adhesive assembly 3802.

[0222] 39A-39D illustrate another example of an adhesive assembly 3902 that mates with an electronics housing 3904, according to some embodiments. The adhesive assembly 3902 can include first mating portions 3906A, 3906B. The first mating portion 3906A can be configured to mate with a second mating portion 3908A on the electronics housing 3904. In some examples, there is a single mating portion on the electronics housing 3904 and / or the adhesive assembly 3902. In some examples, there are multiple first mating portions on the adhesive assembly 3902 and / or multiple second mating portions on the electronics housing 3904. Advantageously, the adhesive can remain on the body, and the electronics housing can be replaced for a number of reasons, such as for ease of application, to replace the battery, to download data from a patch, and / or for other such reasons. Alternatively, the adhesive can be quickly replaced while the same electronics is used.

[0223] 40A and 40B show examples of an electronics housing that mates with an adhesive assembly, according to some embodiments. For example, FIG. 40A and / or FIG. 40B can include one or more of the examples of FIGS. 39A-39D with a top cover on the housing. The electronics housing 4004 can snap onto certain fasteners of the adhesive assembly 4002. The electronics housing 4004 can include an LED for emitting light from, and / or a detector for detecting, the light from, the patient's skin.

[0224] 41 shows graphs of ECG and PPG signals for determining PAT according to some embodiments. PAT can be calculated as an integral according to the following formula:

[0225]

number

[0226] In some embodiments, PAT can be calculated using ECG-R peak to PPG peak information and / or ECG-R peak to PPG foot / trough information. In other embodiments, PAT can be calculated using the integral of the PPG signal by weighting each new sample by its amplitude.

[0227] FIG. 42 shows a graph for calculating PAT as an integral using different integral intervals, according to some examples. In some embodiments, the system can take the integral over each ECG beat 4202 (the time period between ECG-R peaks) or each PPG beat 4206 (using the valleys as the start / stop times). Advantageously, PAT determination is robust for noisy PPG signals because the determination does not depend on accurate determination of PPG peaks. One advantage of using ECG beats is that calculating the integral over each ECG beat provides additional reliability for noisy PPG data that has valleys that are different or difficult to accurately detect.

[0228] Each of the processes, methods, and algorithms described in the preceding sections may be embodied in code modules executed by one or more computer systems or computer processors comprising computer hardware and may be fully or partially automated by the code modules. The code modules may be stored on any type of non-transitory computer-readable medium or computer storage device, such as a hard drive, solid-state memory, optical disk, and / or the like. The systems and modules may also be transmitted as a generated data signal (e.g., as part of a carrier wave or other analog or digital propagated signal) over various computer-readable transmission media, including wireless-based and wired / cable-based media, and may take various forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). The processes and algorithms may be implemented partially or entirely in application-specific circuitry. The results of the disclosed processes and process steps may be stored, persistently or otherwise, in any type of non-transitory computer storage, such as, for example, volatile or non-volatile storage.

[0229] The various features and processes described above can be used independently of one another or can be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of the present disclosure. In addition, in some embodiments, certain method or process blocks can be omitted. Also, the methods and processes described herein are not limited to a particular order, and the blocks or states associated therewith can be executed in other orders as appropriate. For example, the described blocks or states can be executed in an order other than the order specifically disclosed, or multiple blocks or states can be combined into a single block or state. The illustrated blocks or states can be executed serially, in parallel, or in other ways. Blocks or states can be added or deleted from the disclosed embodiments. The example systems and components described herein can be configured differently from those described. For example, elements can be added, deleted, or rearranged compared to the disclosed embodiments.

[0230] In particular, conditional language such as "can," "could," "might," or "might," unless specifically stated otherwise or as understood within the context in which it is used, is intended to generally convey that certain examples include certain features, elements, and / or steps, while other examples do not include certain features, elements, and / or steps. Thus, such conditional language does not generally imply that features, elements, and / or steps are somehow required for one or more examples, or that one or more examples necessarily include logic for determining whether these features, elements, and / or steps are included in or performed in any particular example, with or without user input or prompting. The term "comprises" means "including, but not limited to." The term "or" means "and / or."

[0231] It should be understood that the process descriptions, elements, or blocks in the flow diagrams or block diagrams described herein and / or depicted in the accompanying figures may represent modules, segments, or portions of code that comprise one or more executable instructions for implementing specific logical functions or steps in the process. Also included within the scope of the embodiments described herein are alternative embodiments in which elements or functions are omitted or performed in a different order than that shown or described, including substantially simultaneously or in reverse order, depending on the functionality involved, as would be understood by one skilled in the art.

[0232] All of the methods and processes described above may be at least partially embodied in software code modules executed by one or more computers and may be partially or fully automated. For example, the methods described herein may be executed by a computing system and / or any other suitable computing device. The methods may be executed on a computing device in response to the execution of software instructions or other executable code read from a tangible computer-readable medium. A tangible computer-readable medium is a data storage device capable of storing data readable by a computer system. Examples of computer-readable media include read-only memory, random-access memory, other volatile or non-volatile memory devices, CD-ROMs, magnetic tape, flash drives, optical data storage devices, etc.

[0233] It should be emphasized that many variations and modifications can be made to the above-described embodiments, and that elements thereof are understood to be among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. The foregoing description details particular embodiments. However, no matter how detailed the foregoing may be, it will be understood that the systems and methods can be implemented in many ways. For example, features of one embodiment can be used with features of a different embodiment. Also, as noted above, it should be noted that the use of a particular term when describing a particular feature or aspect of the systems and methods should not be construed as meaning that the term is redefined herein to be limited to include any particular feature of the feature or aspect of the systems and methods with which the term is associated.

[0234] Various embodiments of physiological monitoring devices, methods, and systems are disclosed herein. These various embodiments may be used alone or in combination, and various modifications to individual features of the embodiments may be made without departing from the scope of the present invention. For example, the order of various method steps may be changed in some cases, and / or one or more optional features may be added to or deleted from the described devices. Accordingly, the description of the embodiments provided above should not be construed as unduly limiting the scope of the present invention, which is defined in the appended claims.

[0235] Various modifications can be made to the embodiments described in this disclosure, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the scope of the disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with this disclosure, the principles and novel features disclosed herein.

[0236] Certain features that are described herein in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, while features may be described above as acting in a particular combination, and may even initially be claimed as such, one or more features from a claimed combination can, in some cases, be removed from the combination, and the claimed combination can be directed to a subcombination or a variation of the subcombination.

[0237] Similarly, although operations are depicted in the figures in a particular order, such operations need not be performed in the particular order shown, or sequentially, to achieve desirable results, nor need all of the illustrated operations be performed. Furthermore, the figures may generally depict one or more exemplary steps in the form of a flow diagram. However, other operations not shown may be incorporated into the generally illustrated exemplary steps. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. Furthermore, the separation of various system components in the above-described embodiments should not be construed as requiring such separation in all embodiments. Furthermore, other embodiments are within the scope of the following claims. In some cases, the operations recited in the claims may be performed in a different order and still achieve desirable results.

Claims

1. 1. An electronic device configured to monitor a physiological signal of a user, comprising: The electronic device is a housing at least partially enclosing a circuit board configured to process physiological signals to infer a physiological characteristic of the user; flexible wings extending from the housing and configured to be attached to a surface of the user; an optical sensor assembly disposed on the flexible wing and configured to obtain a photoplethysmogram signal; the optical sensor assembly includes an optical emitter configured to emit light and an optical detector configured to receive light, wherein at least a portion of the light emitted by the optical emitter is directed toward the user's skin and received from the user's skin by the optical detector, and the optical sensor assembly further includes a first directional layer between the optical emitter and the user's surface and a second directional layer between the optical detector and the user's surface, wherein the first directional layer directs light from the optical emitter toward the user's surface and the second directional layer directs light from the user's surface toward the optical detector. electronic equipment.

2. the first directional layer includes a first convex lens, and the second directional layer includes a second convex lens; The electronic device of claim 1 .

3. the first convex lens and the second convex lens are arranged to extend below the flexible wing so that the first convex lens and the second convex lens are pressed against the user's skin when the electronic device is attached to the user's skin.

3. The electronic device of claim 2.

4. the optical sensor assembly further includes an opaque barrier disposed between the first directional layer and the second directional layer; The electronic device according to any one of claims 1 to 3.

5. the opaque barrier prevents at least a portion of the light emitted by the light emitter from being received by the light detector without passing through the user's skin; 5. The electronic device of claim 4.

6. the opaque barrier is configured to direct at least a portion of the light from the surface of the user to the light detector.

6. The electronic device according to claim 4 or 5.

7. further comprising a reflective layer disposed between the opaque barrier and the user's skin. The electronic device according to any one of claims 4 to 6.

8. the reflective layer reflects light from the first directional layer; 8. The electronic device of claim 7.

9. the first directional layer and the second directional layer protrude beyond a portion of the opaque barrier and overlap at least a portion of the opaque barrier to increase the contact area with the user's skin; The electronic device according to any one of claims 4 to 8.

10. the first directional layer and the second directional layer are configured to guide or redirect the passage of light of a particular wavelength; The electronic device according to any one of claims 1 to 9.

11. the first directional layer includes a first concave lens, and the second directional layer includes a second concave lens; The electronic device of claim 1 .

12. the first concave lens and the second concave lens are formed from a high index material that is index-matched to the stratum corneum of the user's chest; 12. The electronic device of claim 11.

13. the first directional layer includes a first half-ball lens, and the second directional layer includes a second half-ball lens; The electronic device of claim 1 .

14. the first half-ball lens and the second half-ball lens each comprise a sapphire half-ball lens; 14. The electronic device of claim 13.

15. a first adhesive layer configured to attach the first half ball lens to the light emitter, and a second adhesive layer configured to attach the second half ball lens to the light detector.

15. An electronic device according to claim 13 or 14.

16. the circuit board comprises a flex circuit board; The electronic device according to any one of claims 1 to 15.

17. a backing substrate that exerts pressure on the circuit board to increase contact between the light emitter and the user's skin, to increase contact between the light detector and the user's skin, or to increase contact between the light emitter and the user's skin and between the light detector and the user's skin; The electronic device according to any one of claims 1 to 16.

18. the optical sensor assembly includes a plurality of light emitters including the light emitter, and when the flexible wing is attached to the surface of the user, the plurality of light emitters sandwich the user's skin such that a portion of the skin is located between the plurality of light emitters, and the plurality of light emitters focus light toward the portion of the skin located between the plurality of light emitters. The electronic device according to any one of claims 1 to 17.

19. the optical sensor assembly includes a plurality of photodetectors including the photodetector, and when the flexible wing is attached to the surface of the user, the plurality of photodetectors sandwich the user's skin, positioning a portion of the skin between the plurality of photodetectors, and the plurality of photodetectors receive light from the portion of the skin positioned between the plurality of photodetectors. The electronic device according to any one of claims 1 to 18.

20. when the flexible wing is attached to the surface of the user, the light emitter and the light detector sandwich the user's skin, with a portion of the skin positioned between the light emitter and the light detector, and light from the light emitter is directed through the user's skin to the light detector. The electronic device according to any one of claims 1 to 19.

21. the optical sensor assembly further includes a fiber optic cable or light guide configured to direct light from the light emitter toward the user's skin. The electronic device according to any one of claims 1 to 20.

22. a spring configured to exert pressure to increase contact between the light emitter and the user's skin and to increase contact between the light detector and the user's skin. An electronic device according to any one of claims 1 to 21.

23. 1. An electronic device configured to monitor a physiological signal of a user, comprising: The electronic device is a housing at least partially enclosing a circuit board configured to process physiological signals to infer a physiological characteristic of the user; flexible wings extending from the housing and configured to conform to a surface of the user corresponding to the user's chest; an optical sensor assembly disposed on the flexible wing and configured to obtain a photoplethysmogram signal; an adhesive layer coupled to a surface of the flexible wing and configured to adhere the electronic device to a surface of the user, the adhesive layer comprising an optically clear adhesive layer; 2. An electronic device comprising:

24. further comprising a brightness enhancement film configured to reflect or refract light generated by the light sensor assembly toward the user's skin.

24. The electronic device of claim 23.

25. the brightness enhancing film is disposed between the adhesive layer and the photosensor assembly.

25. The electronic device of claim 24.

26. the brightness enhancement film is integrated with the adhesive layer; 25. The electronic device of claim 24.

27. the brightness enhancement film is substantially coplanar with the optical elements of the photosensor assembly; 25. The electronic device of claim 24.

28. the brightness enhancement film rises toward the circuit board and provides a space for tenting the user's skin.

25. The electronic device of claim 24.

29. the optical sensor assembly includes a photodiode and a light emitting diode; The electronic device according to any one of claims 23 to 28.

30. an optically clear adhesive layer coupling the photodiode and the light emitting diode to the user's skin; 30. The electronic device of claim 29.

31. the optically transparent adhesive layer surrounds the photodiode and the light emitting diode without covering them; 30. The electronic device of claim 29.

32. further comprising a moisture-wicking material configured to absorb or evaporate sweat or bodily secretions; 24. The electronic device of claim 23.

33. the moisture-wicking material comprises a polyester-based material; 33. The electronic device of claim 32.

34. the moisture-absorbing material is interwoven with the adhesive layer; 34. An electronic device according to claim 32 or 33.

35. the moisture-absorbing material is disposed around an optical element of the optical sensor assembly; The electronic device according to any one of claims 32 to 34.

36. and a channel disposed around an optical element of the optical sensor assembly and configured to allow sweat or bodily secretions to evaporate or escape. The electronic device according to any one of claims 23 to 35.

37. the channel is in the adhesive layer; 37. The electronic device of claim 36.

38. the circuit board comprises a flexible printed circuit board; The electronic device according to any one of claims 23 to 37.

39. The flexible printed circuit board includes a backing layer having channels that allow sweat or body secretions to evaporate or escape.

39. The electronic device of claim 38.

40. the adhesive layer and the optical element of the optical sensor assembly are attached to a backing layer; 40. The electronic device according to any one of claims 23 to 39.

41. further comprising a physical barrier between the adhesive layer and the optical element to prevent adhesive leaks from contacting the optical element.

41. The electronic device of claim 40.

42. the physical barrier slopes toward the adhesive layer; 42. The electronic device of claim 41.

43. the adhesive layer comprises a plurality of adhesives; An electronic device according to any one of claims 23 to 42.

44. the plurality of adhesives include a first adhesive and a second adhesive, the first adhesive being closer to the optical element of the optical sensor assembly than the second adhesive, and the viscosity of the first adhesive being different from the viscosity of the second adhesive; 44. The electronic device of claim 43.

45. the first adhesive is thinner than the second adhesive; 45. The electronic device of claim 44.

46. further comprising an adhesive layer at least partially surrounding the optical sensor assembly. An electronic device according to any one of claims 23 to 45.

47. the adhesive layer at least partially surrounding the optical sensor assembly is not optically transparent; 47. An electronic device according to any one of claims 46 to 48.

48. further comprising a hydrophobic or hydrophilic material at least partially surrounding the optical sensor assembly to direct sweat or body secretions away from the optical sensor assembly; An electronic device according to any one of claims 23 to 47.

49. and further comprising perforations disposed around an optical element of the optical sensor assembly and configured to allow sweat or bodily secretions to evaporate or escape. An electronic device according to any one of claims 23 to 48.

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